Unit One
第一单元

Reading Material
阅读材料

Passage 2
第 2 段

Building machines that better understand human goals
构建更能理解人类目标的机器

A new algorithm capable of inferring goals and plans could help machines better adapt to the imperfect nature of human planning.
一种能够推断目标和计划的新算法可以帮助机器更好地适应人类规划的不完美性质。

Rachel Gordon | MIT CSAIL
雷切尔·戈登 |使用 CSAIL

Publication Date:December 14, 2020
出版日期：2020 年 12 月 14 日

1)While there’s been considerable work on inferring the goals and desires of agents, much of this work has assumed that agents act optimally to achieve their goals.
1） 虽然在推断代理人的目标和愿望方面已经做了大量工作，但大部分工作都假设代理人以最佳方式实现他们的目标。

2)However, the team was particularly inspired by a common way of human planning that’s largely sub-optimal: not to plan everything out in advance, but rather to form only partial plans, execute them, and then plan again from there. While this can lead to mistakes from not thinking enough “ahead of time,” it also reduces the cognitive load.
2） 然而，该团队特别受到一种常见的人类规划方式的启发，这种方式在很大程度上是次优的：不是提前规划所有事情，而是只制定部分计划，执行它们，然后从那里再次规划。虽然这可能会导致因没有“提前”思考而出现错误，但它也会减轻认知负荷。

3)For example, imagine you're watching your friend prepare food, and you would like to help by figuring out what they’re cooking. You guess the next few steps your friend might take: maybe preheating the oven, then making dough for an apple pie. You then “keep” only the partial plans that remain consistent with what your friend actually does, and then you repeat the process by planning ahead just a few steps from there.
3） 例如，假设您正在观看您的朋友准备食物，您想通过弄清楚他们在做什么来提供帮助。你猜你的朋友接下来可能会采取的几个步骤：也许是预热烤箱，然后做苹果派的面团。然后，你只 “保留 ”与你的朋友实际所做的保持一致的部分计划，然后你通过提前计划几个步骤来重复这个过程。

4)Once you've seen your friend make the dough, you can restrict the possibilities only to baked goods, and guess that they might slice apples next, or get some pecans for a pie mix. Eventually, you'll have eliminated all the plans for dishes that your friend couldn't possibly be making, keeping only the possible plans (i.e., pie recipes). Once you're sure enough which dish it is, you can offer to help.
4） 一旦你看到你的朋友做面团，你就可以把可能性限制在烘焙食品上，并猜测他们接下来可能会切苹果，或者买一些山核桃来做馅饼混合物。最终，您将消除您的朋友不可能制作的菜肴的所有计划，只保留可能的计划（即馅饼食谱）。一旦你确定这是哪道菜，你就可以提供帮助。

5)The team’s inference algorithm, called “Sequential Inverse Plan Search (SIPS)”, follows this sequence to infer an agent's goals, as it only makes partial plans at each step, and cuts unlikely plans early on. Since the model only plans a few steps ahead each time, it also accounts for the possibility that the agent — your friend — might be doing the same. This includes the possibility of mistakes due to limited planning, such as not realizing you might need two hands free before opening the refrigerator. By detecting these potential failures in advance, the team hopes the model could be used by machines to better offer assistance.
5） 该团队的推理算法称为“顺序逆向计划搜索 （SIPS）”，它遵循此顺序来推断代理的目标，因为它在每个步骤中只制定部分计划，并在早期削减不太可能的计划。由于该模型每次只提前计划几步，因此它还考虑了代理（您的朋友）可能正在执行相同作的可能性。这包括由于计划有限而出错的可能性，例如在打开冰箱之前没有意识到您可能需要解放两只手。通过提前检测这些潜在的故障，该团队希望机器可以使用该模型来更好地提供帮助。

6)“One of our early insights was that if you want to infer someone’s goals, you don’t need to think further ahead than they do. We realized this could be used not just to speed up goal inference, but also to infer intended goals from actions that are too shortsighted to succeed, leading us to shift from scaling up algorithms to exploring ways to resolve more fundamental limitations of current AI systems,” says Vikash Mansinghka, a principal research scientist at MIT and one of Tan Zhi-Xuan's co-advisors, along with Joshua Tenenbaum, MIT professor in brain and cognitive sciences. “This is part of our larger moonshot — to reverse-engineer 18-month-old human common sense.”
6）”我们早期的见解之一是，如果您想推断某人的目标，您不需要比他们想得更远。我们意识到这不仅可以用于加速目标推断，还可以从目光短浅而无法成功的行动中推断出预期目标，从而引导我们从扩展算法转向探索解决当前 AI 系统更基本限制的方法，“麻省理工学院首席研究科学家、Tan Zhi-Xuan 的联合顾问之一 Vikash Mansinghka 说。 以及麻省理工学院大脑和认知科学教授 Joshua Tenenbaum。“这是我们更大的大胆创新计划的一部分 - 对 18 个月大的人类常识进行逆向工程。”

7)The work builds conceptually on earlier cognitive models from Tenenbaum's group, showing how simpler inferences that children and even 10-month-old infants make about others' goals can be modeled quantitatively as a form of Bayesian inverse planning.
7） 这项工作在概念上建立在 Tenenbaum 小组的早期认知模型之上，展示了儿童甚至 10 个月大的婴儿对他人目标所做的简单推断如何被定量建模为贝叶斯逆向规划的一种形式。

8)While to date the researchers have explored inference only in relatively small planning problems over fixed sets of goals, through future work they plan to explore richer hierarchies of human goals and plans. By encoding or learning these hierarchies, machines might be able to infer a much wider variety of goals, as well as the deeper purposes they serve.
8） 虽然迄今为止，研究人员仅在固定目标集上相对较小的规划问题中探索了推理，但通过未来的工作，他们计划探索人类目标和计划的更丰富的层次结构。通过编码或学习这些层次结构，机器可能能够推断出更广泛的目标，以及它们所服务的更深层次的目的。

9)“Though this work represents only a small initial step, my hope is that this research will lay some of the philosophical and conceptual groundwork necessary to build machines that truly understand human goals, plans and values,” says Xuan. “This basic approach of modeling humans as imperfect reasoners feels very promising. It now allows us to infer when plans are mistaken, and perhaps it will eventually allow us to infer when people hold mistaken beliefs, assumptions, and guiding principles as well.”
9）”虽然这项工作只是一小步，但我希望这项研究将为构建真正理解人类目标、计划和价值观的机器奠定一些必要的哲学和概念基础，“Xuan 说。“这种将人类建模为不完美推理者的基本方法感觉非常有前途。它现在使我们能够推断计划何时出错，也许它最终也会让我们推断人们何时持有错误的信念、假设和指导原则。

10)Zhi-Xuan, Mansinghka, and Tenenbaum wrote the paper alongside EECS graduate student Jordyn Mann and PhD student Tom Silver. They virtually presented their work last week at the Conference on Neural Information Processing Systems (NeurIPS 2020).
10）Zhi-Xuan、Mansinghka 和 Tenenbaum 与 EECS 研究生 Jordyn Mann 和博士生 Tom Silver 一起撰写了这篇论文。他们上周在神经信息处理系统会议 （NeurIPS 2020） 上以虚拟方式展示了他们的工作。

Notes:
笔记：

In the quest to capture the social intelligence in machines, researchers from MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) and the Department of Brain and Cognitive Sciences created an algorithm capable of inferring goals and plans, even when those plans might fail. To create their model the team used Gen, a new AI programming platform recently developed at MIT, to combine symbolic AI planning with Bayesian inference. The team’s model performed 20 to 150 times faster than an existing baseline method called Bayesian Inverse Reinforcement Learning (BIRL), which learns an agent’s objectives, values, or rewards by observing its behavior, and attempts to compute full policies or plans in advance.
为了在机器中捕获社交智能，麻省理工学院计算机科学与人工智能实验室 （CSAIL） 和大脑与认知科学系的研究人员创造了一种能够推断目标和计划的算法，即使这些计划可能失败。为了创建他们的模型，该团队使用了  麻省理工学院最近开发的新 AI 编程平台 Gen，将符号 AI 规划与贝叶斯推理相结合。 该团队的模型的执行速度比称为贝叶斯逆强化学习 （BIRL） 的现有基线方法快 20 到 150 倍，后者通过观察代理的行为来学习代理的目标、价值观或奖励。 并尝试提前计算完整的策略或计划。

agent:具有自主性、交互性等特征的活着的计算实体。

Moonshot (para.6): 一个疯狂的想法或不大可能实现的项目

Reverse engineer (para.6)：Reverse engineering is taking apart an object to see how it works in order to duplicate or enhance the object.
逆向工程 （第 6 段）：逆向工程是拆解一个对象，看看它是如何工作的，以便复制或增强该对象。

Bayesian inverse planning(para.7)：a model of rational planning. Inverse planning refers to the problem of learning a probabilistic model of the dynamics of a robot (or a human) by observing her optimal behavior performing a given task.
贝叶斯逆向规划 （para.7）：理性规划模型。逆向规划是指通过观察机器人（或人类）执行给定任务的最佳行为来学习机器人（或人类）动力学的概率模型的问题。

U2 P1

The business of quantum computers
量子计算机的业务

By exploiting the counter-intuitive properties of quantum mechanics, they could perform some calculations (though only some) faster than any conceivable non-quantum machine. For one thing, they would probably be much more rapid than any classical computer at searching a database—an elemental operation with a thousand uses. 
通过利用量子力学的反直觉特性，他们可以比任何可以想象的非量子机器更快地执行一些计算（尽管只是一些）。首先，它们在搜索数据库时可能比任何经典计算机都快得多 — 这是一种具有一千种用途的基本作。

They would be quicker at more specific tasks, too. Precisely simulating all but the simplest chemical reactions is mathematically intractable for any non-quantum computer, no matter how huge. A quantum computer could do this, aiding the development of drugs, catalysts and batteries. 
他们在更具体的任务上也会更快。对于任何非量子计算机来说，精确模拟除最简单的化学反应之外的所有化学反应在数学上都是困难的，无论它有多大。量子计算机可以做到这一点，帮助开发药物、催化剂和电池。

Quantum computers would also speed up the analysis of optimisation problems, which try to find the best way to juggle many variables in order to maximise a particular outcome. That would be a boon to the transport industry (by finding efficient routes) and to finance (by maximising profits given a set of constraints). 
量子计算机还将加快对优化问题的分析，这些问题试图找到   处理许多变量的最佳方法，以最大化特定结果。 这将有利于运输业（通过寻找有效的路线）和金融业（通过在一系列约束条件下实现利润最大化）。 

Boston Consulting Group (BCG), a management consultancy, foresees quantum computers improving the operating income of their users by between $450bn and $850bn a year by 2050.Unfortunately, big, stable quantum computers do not yet exist. But small, ornery, unstable ones do. 
管理咨询公司波士顿咨询集团 （BCG） 预计，到 2050 年，量子计算机每年可为其用户的营业收入提高 4500 亿至 8500 亿美元。但小的、暴躁的、不稳定的可以。

  John Preskill, a quantum-computing researcher at the California Institute of Technology, dubs such machines NISQS—Noisy, Intermediate-Scale Quantum computers. 
加州理工学院的量子计算研究员约翰·普雷斯基尔 （John Preskill） 将这种机器称为 NISQS，即嘈杂的中等规模量子计算机。

Some see NISQS as mere stepping stones towards size and stability, and that is certainly the goal of those working on them. A growing number of companies and investors, however, are hopeful that NISQS themselves will be able to do useful work in the meantime. 
有些人认为 NISQS 只是迈向规模和稳定性的垫脚石，这无疑是从事其工作的人的目标。然而，越来越多的公司和投资者希望 NISQS 本身在此期间能够做有用的工作。

These firms are hunting for "quantum advantage"—a way in which even today's limited machines might have an impact on their bottom lines, or those of their customers. For most of the field's history, quantum-computing research has been backed by governments or big information-technology firms. Increasingly, though, the venture-capital (VC) industry is showing an interest. 
这些公司正在寻找“量子优势”，即即使是当今有限的机器也可能对他们或客户的底线产生影响。在该领域的大部分历史中，量子计算研究一直得到政府或大型信息技术公司的支持。不过，风险投资 （VC） 行业也越来越表现出兴趣。

PitchBook, a research firm based in Seattle,has tracked $495m of vc money that has been invested in quantum computing so far this year—almost double last year's total. Dozens of startups are competing with the incumbent tech giants. 
总部位于西雅图的研究公司 PitchBook 追踪了今年迄今为止投资于量子计算的 $495m 风险投资资金，几乎是去年总额的两倍。数十家初创公司正在与现有的科技巨头竞争。

And established companies, such as Daimler, a carmaker, and Goldman Sachs, a bank, are beginning to experiment with the nascent industry's products, hoping that, if they can master them, they will bestow an advantage over their competitors. Much of the money is going towards building hardware. 
老牌公司，如汽车制造商戴姆勒（Daimler）和银行高盛（Goldman Sachs），开始试验这个 新兴   行业的产品，希望如果他们能够掌握这些产品，就能获得超越竞争对手的优势。 大部分资金都用于制造硬件。 

Doug Finke, a physicist who runs the Quantum Computing Report, which focuses on the nascent industry, is aware of 87 organisations, big and small, trying to construct quantum computers. Unlike classical computing, which had settled by the 1970s on silicon transistors as the units of computation, there is, as yet, no consensus on the best way to build a quantum computer. 
物理学家道格·芬克 （Doug Finke） 负责管理专注于新兴行业的量子计算报告，他知道有 87 个大大小小的组织试图构建量子计算机。与 1970 年代以硅晶体管作为计算单位的经典计算不同，到目前为止，对于构建量子计算机的最佳方法尚未达成共识。

IonQ, a firm in Maryland that has raised $84m,uses trapped ytterbium ions, manipulated by lasers, to perform its calculations. Rigetti Computing, a Californian company which announced earlier this month that it would be building a quantum computer for the British government, Rigetti Computing employs microwaves to control pairs of electrons flowing through superconducting circuits. 
马里兰州的一家公司 IonQ 已经筹集了 $84m，它使用由激光纵的捕获镱离子来执行计算。Rigetti Computing 是一家加利福尼亚公司，本月早些时候宣布将为英国政府建造一台量子计算机，Rigetti Computing 使用微波来控制流经超导电路的电子对。

Microsoft, although very much not a startup, is working on a "topological" quantum computer that relies on the interactions of super-cold electrons. One particularly well-financed new firm is Psi Quantum, which does its computing with photons that run along waveguides etched onto ordinary silicon chips. 
Microsoft 虽然不是一家初创公司，但正在开发一种依赖于超冷电子相互作用的“拓扑”量子计算机。Psi Quantum 是一家资金特别雄厚的新公司，它使用沿着蚀刻在普通硅芯片上的波导运行的光子进行计算。

It hopes to leapfrog the NISQ era entirely and produce a fully fledged quantum computer within about five years—though that is far sooner than most experts think feasible. PsiQuantum was founded in 2015 by researchers from Imperial College and the University of Bristol, both in Britain. 
它希望完全跨越 NISQ 时代，并在大约五年内生产出一台成熟的量子计算机——尽管这比大多数专家认为可行的要快得多。PsiQuantum 由来自英国帝国理工学院和布里斯托大学的研究人员于 2015 年创立。

It has raised $215m from backers including Black-Rock, a giant investment firm, and the Founders Fund, an American vc company that was an early investor in Space X and Facebook. 
它已从包括大型投资公司 Black-Rock 和美国风险投资公司 Founders Fund 在内的支持者那里筹集了 $215m，后者是 Space X 和 Facebook 的早期投资者。

Microsoft (whose own topological machines are still at an early stage of development) offers access via Azure, its cloud-computing service, to machines from IonQ, Honeywell and a company called Quantum Circuits. Amazon hosts machines from Rigetti, IonQ and D-Wave, a Canadian company that builds specialised, fixed-purpose computers called quantum annealers. 
Microsoft（其自己的拓扑计算机仍处于开发的早期阶段）通过其云计算服务 Azure 提供对 IonQ、Honeywell 和一家名为 Quantum Circuits 的公司的计算机的访问。亚马逊托管了来自 Rigetti、IonQ 和 D-Wave 的机器，D-Wave 是一家加拿大公司，制造称为量子退火器的专用固定用途计算机。

Rather than have hardware-makers come up with useful algorithms, the hope is that existing businesses, by being given access to the machines in this way, will invent such algorithms for themselves. With that in mind, says Krysta Svore, who leads Microsoft's quantum-computing research, one task is to make those machines as easy as possible to use. 
与其让硬件制造商想出有用的算法，不如希望现有的企业以这种方式获得对机器的访问权限，为自己发明这样的算法。负责 Microsoft 量子计算研究的 Krysta Svore 说，考虑到这一点，一项任务是使这些机器尽可能易于使用。

The firm has developed tools intended to help customers wrap their brains around the counter-intuitive properties of quantum computers. It has also developed software intended to smooth over differences between machines from different makers, so that programmers do not have to worry about whether they are marshalling ions or electrons. 
该公司开发了一些工具，旨在帮助客户了解量子计算机的反直觉特性。它还开发了旨在消除不同制造商机器之间差异的软件，这样程序员就不必担心它们是编组离子还是电子。

She compares this to the early days of classical computing, when the development of compilers and early programming languages freed human beings from the need to think in the ones and zeros of raw machine code. 
她将此与经典计算的早期进行了比较，当时编译器和早期编程语言的发展使人类摆脱了用原始机器代码的 1 和 0 思考的需要。

The big question is what all this is leading up to. Despite the excitement, the industry's commercial pioneers have their work cut out for them. There is plenty of promise, but, as yet, no certainty. Finding algorithms that are both commercially useful and simple enough to work within a NISQ machine's limitations is not easy. 
最大的问题是这一切导致了什么。尽管令人兴奋，但该行业的商业先驱们还有他们的工作要做。前景广阔，但目前尚不确定。找到既商业上有用又足够简单的算法，以便在 NISQ 机器的限制下工作并不容易。

A report published last year by America's National Academy of Sciences reminded readers that no commercial applications are currently known to exist. The first step, then, is to go looking.
美国国家科学院去年发表的一份报告提醒读者，目前尚无已知的商业应用存在。那么，第一步是去寻找。

The industry has been cheered by Google's demonstration last year of "quantumsupremacy", in which it used a NISQ machine to perform, with minutes of computing time, a calculation that would have taken thousands of years on classical hardware. Google's calculation was highly contrived and of little use in the real world. But it proved a point.
谷歌去年演示的“量子霸权”让该行业欢呼雀跃，在该演示中，它使用 NISQ 机器以几分钟的计算时间执行了一项在传统硬件上需要数千年的计算。Google 的计算是高度人为的，在现实世界中几乎没有用处。但事实证明，这是有道理的。

U2 P2

ByteDance
字节跳动

China's first global software company is going from strength to strength. America doesn't like it one bit 
中国第一家全球性软件公司正在不断发展壮大。美国一点也不喜欢

As covid-19 has forced the world's teenagers out of school and into their rooms, they have turned to a familiar digital companion, TikTok. The short-video app was downloaded 115m times in March. 
随着 covid-19 迫使世界各地的青少年走出学校，进入他们的房间，他们转向了熟悉的数字伴侣 TikTok。该短视频应用程序在 3 月份被下载了 115m 次。

Its nearly 1bn regular users enjoy silly clips of dog antics alongside pandemic advice from the World Health Organisation. Collectively, TikTok videos tagged with #coronavirus have been watched 53bn times. 
其近 10 亿的普通用户喜欢狗滑稽动作的愚蠢片段以及世界卫生组织的大流行建议。总的来说，带有 #coronavirus 标签的 TikTok 视频已被观看 530 亿次。

TikTok's popularity over the past two years has shone the spotlight on ByteDance, its Beijing-based developer. Founded by a Chinese computer scientist, Zhang Yiming, in 2011, it is now the world's biggest unlisted technology “unicorn”, recently valued at between $90bn and$100bn. 
TikTok 在过去两年中的受欢迎程度使总部位于北京的开发商字节跳动成为人们关注的焦点。它由中国计算机科学家张一鸣于 2011 年创立，现在是世界上最大的未上市科技“独角兽”，最近的估值在 900 亿至 1000 亿美元之间。

It is also the only technology firm bar Apple with more than 100m users in both China and America, where TikTok has taken on the likes of YouTube and Instagram. 
它也是唯一一家在中国和美国拥有超过 100m 用户的科技公司，TikTok 已经与 YouTube 和 Instagram 等人竞争。

And ByteDance isn't done. The 60,000 people in its buzzy offices—“We are like flies,” says one former employee—crank out one app after another. In the past year it has launched a worldwide corporate-software service (Lark), a music-streaming app in India and Indonesia(Resso) and, in China, a messaging rival to WeChat. 
字节跳动还没有结束。60,000 名员工在热闹的办公室里 — “我们就像苍蝇，”一位前员工说 — 一个接一个地开发应用程序。去年，它推出了一项全球企业软件服务 （Lark），在印度和印度尼西亚推出了一款音乐流媒体应用程序 （Resso），并在中国推出了微信的竞争对手。

As other firms sack workers amid covid-19, ByteDance is hiring 10,000 globally. It plans to employ 30,000 on top of that this year. ByteDance is not the first Chinese firm with foreign ambitions. 
当其他公司在 covid-19 期间解雇员工时，字节跳动正在全球招聘 10,000 名员工。它计划今年在此基础上雇用 30,000 名员工。字节跳动并不是第一家有海外野心的中国公司。

Commodity giants such as CNOOC, an oil firm, have been buying foreign reserves, and rivals, since the 1990s. In the past decade industrial giants have pursued Western competitors from carmaking (as with Geely's purchase of Volvo) to chemicals (ChemChina's of Syngenta). More haphazardly, conglomerates like Fosun and Anbang splurged on trophy assets (including ClubMed and the Waldorf Astoria hotel, respectively). 
自 1990 年代以来，石油公司中海油等大宗商品巨头一直在购买外汇储备和竞争对手。在过去十年中，工业巨头一直在追逐西方竞争对手，从汽车制造（如吉利收购沃尔沃）到化工（先正达的中国化工）。更随意的是，复星和安邦等企业集团在奖杯资产上挥霍（分别包括 ClubMed 和华尔道夫酒店）。

Unlike most of its peripatetic predecessors, though, ByteDance has built its empire by making products that appeal beyond China. It is China's first global software giant. It has also courted foreign investors. 
不过，与大多数四处游荡的前辈不同，字节跳动通过制造吸引中国以外的产品来建立自己的帝国。是中国第一家全球性软件巨头。它还吸引了外国投资者。

Filings in Hong Kong show that it has used an arrangement called the “Sina structure”, which allows it to accept money from abroad, since its founding (many Chinese tech firms turn to this structure only when eyeing a stockmarket listing in America). Around 80% of ByteDance's investors are non-Chinese. So are four of its five board members. The other is Mr Zhang. 
在香港提交的文件显示，自成立以来，它一直使用一种称为“新浪结构”的安排，允许它接受来自国外的资金（许多中国科技公司只有在考虑在美国上市时才会转向这种结构）。字节跳动大约 80% 的投资者是非中国人。其五名董事会成员中的四名也是如此。另一位是张先生。

All this helps ensure ByteDance is not, in contrast to many Chinese tech upstarts, in hock to Alibaba, Baidu and Tencent— which is handy, for Bytedance competes with China's tech titans for ad revenue. It makes most of its money selling ads in its two main Chinese apps: Douyin, a Chinese TikTok, and Toutiao, a multimedia-and-news app akin to Facebook's news feed (itsWeChat rival, Duoshan, disappointed). 
与许多中国科技新贵相比，所有这些都有助于确保字节跳动不会像阿里巴巴、百度和腾讯那样落后于阿里巴巴、百度和腾讯——这很方便，因为字节跳动与中国的科技巨头争夺广告收入。它的大部分收入来自其两个主要的中国应用程序：抖音（中国的 TikTok）和今日头条（类似于 Facebook 的新闻源的多媒体和新闻应用程序）（它的竞争对手多山令人失望）。

How much money it makes, exactly, is unclear: as a private company Bytedance does not publish its accounts. But leaks and statements from investors put last year's revenue at between 104bn yuan and 140bn yuan ($15bn-20bn), more than Uber, Snapchat and Twitter combined. 
它到底赚了多少钱，目前尚不清楚：作为一家私营公司，字节跳动不公布其账目。但泄密事件和投资者的声明显示，去年的收入在 1040 亿元至 1400 亿元人民币（150 亿至 200 亿美元）之间，比优步、Snapchat 和 Twitter 的总和还要多。

Its ad revenues in China surpassed Tencent's and Baidu's and now trail only those of Alibaba. It reportedly turned a profit in June 2019, a feat in the world of loss-making unicorns. If the firm generates $25bn in sales this year, as it is expected to despite covid-19, it will have done so three years faster than Facebook. 
它在中国的广告收入超过了腾讯和百度，现在仅次于阿里巴巴。据报道，它在 2019 年 6 月扭亏为盈，这在亏损的独角兽世界中是一项壮举。如果该公司今年的销售额达到 250 亿美元，正如预期的那样，尽管有 covid-19，它将比 Facebook 快三年。

It is the only big Chinese firm whose share of the domestic advertising market is growing fast, from 9% to 17% in 2019, according to Bernstein, a research firm. A recently launched advertising network, Pangle, which lets advertisers reach consumers across any of its non-Chinese apps, may at last help it monetise TikTok. 
根据研究公司伯恩斯坦（Bernstein）的数据，它是唯一一家在国内广告市场份额快速增长的中国大型公司，2019 年从 9%增长到 17%。最近推出的广告网络 Pangle 让广告商可以通过其任何非中国应用程序触达消费者，最终可能会帮助它通过 TikTok 获利。

No wonder American rivals are trying to clip its wings. Facebook’s TikTok clone, Lasso, has flopped. YouTube is said to be developing another (called Shorts). But the biggest threat has emerged in the form of America’s government, wary of China’s rise in any sphere.
难怪美国的竞争对手正试图剪掉它的翅膀。Facebook 的 TikTok 克隆版 Lasso 已经失败。据说 YouTube 正在开发另一个（称为 Shorts）。但最大的威胁已经以美国政府的形式出现，他们对中国在任何领域的崛起都保持警惕。

Politicians in Washington fear that data on American users is being handed to Beijing; that Chinese algorithm designers are infecting impressionable Western youngsters with communist propaganda; and that ByteDance content is censored in line with party whims. 
华盛顿的政客们担心美国用户的数据被交给了北京;中国的算法设计者正在用共产主义的宣传感染易受影响的西方年轻人;字节跳动的内容根据派对的奇思妙想进行审查。

In March two Republican senators introduced a bill that would ban TikTok from all government devices. The Committee on Foreign Investment in the United States (CFIUS) is reviewing ByteDance’s acquisition in 2018 of Musical.ly, another app, which had 60m users in America and Europe. 
今年 3 月，两名共和党参议员提出了一项法案，将禁止所有政府设备使用 TikTok。美国外国投资委员会 （CFIUS） 正在审查字节跳动在 2018 年收购另一款应用程序 Musical.ly 一事，该应用程序在美国和欧洲拥有 60m 用户。

In statements, TikTok has said that it stores all American “user data in the United States” and that its American operations are “not influenced by any foreign government, including the Chinese government”. The firm is trying to mollify critics and has hired prominent security and legal experts in America to help it. 
TikTok 在声明中表示，它将所有美国“用户数据都存储在美国”，并且其美国业务“不受任何外国政府的影响，包括中国政府”。该公司正试图平息批评者，并聘请了美国著名的安全和法律专家来帮助它。

Last month it opened a “transparency centre” in Los Angeles, where it promises to share information about its content-moderation, privacy and security controls, and said it would stop using moderators in China to handle content from users outside the country. 
上个月，它在洛杉矶开设了一个“透明中心”，承诺在那里分享有关其内容审核、隐私和安全控制的信息，并表示将停止使用中国的审核员来处理来自国外用户的内容。

That, most lawyers and technologists reckon, may help get CFIUS off its back. Listing ByteDance in Hong Kong, which is under consideration, may also foster trust. So would anointing a non-Chinese successor—though, at 37, Mr Zhang may not be ready to retire. 
大多数律师和技术人员认为，这可能有助于摆脱 CFIUS 的束缚。字节跳动正在考虑在香港上市，这也可能促进信任。任命非中国继任者也是如此——不过，37 岁的张勇可能还没有准备好退休。

As a last resort, he is said to be willing to contemplate spinning TikTok off. That would cement the digital divide between China and the West—until another hit ByteDance app tries to bridge it.
据说，作为最后的手段，他愿意考虑分拆 TikTok。这将巩固中国和西方之间的数字鸿沟——直到另一个热门应用程序字节跳动试图弥合它。

Unit Three
第三单元

Reading Materials
阅读材料

Passage 1
第 1 段

The Transformative Power of 5G
5G 的变革力量

This once-in-a-decade mobile phone network upgrade is expected to place us squarely in the middle of the Internet of Things
这场十年一遇的移动电话网络升级有望使我们直接处于物联网的中间.

by Scientific American Custom Media
作者：Scientific American Custom Media

1 Major carriers are in the process of rolling out ultra-high-speed mobile-phone networks that use fifth-generation (5G) technology, transmitting data up to 50 times faster than current phone networks. But the promise of 5G is that it will provide more than just a boost to our phone service and download speeds. “5G will be one of the more transformative technologies we’ve had so far,” says Karri Kuoppamaki, vice president of radio network technology and strategy at T-Mobile, where he is overseeing the company’s rollout of 5G networks.
1 主要运营商正在推出使用第五代 （5G） 技术的超高速移动电话网络，其数据传输速度比目前的电话网络快 50 倍。但 5G 的承诺在于，它提供的不仅仅是提升我们的电话服务和下载速度。“5G 将成为我们迄今为止拥有的更具变革性的技术之一，”T-Mobile 无线电网络技术和战略副总裁 Karri Kuoppamaki 说 ，他正在监督该公司的 5G 网络部署。

2 There are three differences between 5G and the current 4G: speed, bandwidth and what network specialists call latency, which is the time it takes for data to move from a server on the network to a device. 5G networks are faster, can handle a higher volume of data, and reduce wait times. The new technology is able to shoot data from millions of local sensors or gadgets to distant cloud computers for processing and then return the relevant guidance — all in a fraction of a second. This deluge of data flooding through our society will enable a host of new services, including connecting new devices and equipment.
阿拉伯数字 5G 和当前的 4G 有三个区别：速度、带宽和网络专家所说的延迟，即数据从网络上的服务器移动到设备所需的时间。5G 网络速度更快，可以处理更多的数据，并减少等待时间。这项新技术能够将来自数百万个本地传感器或小工具的数据发射到遥远的云计算机进行处理，然后返回相关指导——所有这些都在几分之一秒内完成。这种数据洪流在我们的社会中将启用许多新服务，包括连接新的设备和设备。

3 Sensors themselves can be tinier, cheaper and more durable because of yet another advantage of 5G: smaller batteries. 5G devices stay connected to the network instead of engaging in the back-and-forth signaling that 4G networks require for connectivity, which saps battery life. 5G will power up our daily lives. “We’ll constantly have the information we need to make decisions,” Kuoppamaki predicts.
3 由于 5G 的另一个优势：电池更小，传感器本身可以更小、更便宜、更耐用。5G 设备保持与网络的连接，而不是参与 4G 网络连接所需的来回信号，这会缩短电池寿命。5G 将为我们的日常生活提供动力。“我们将不断获得做出决策所需的信息，”Kuoppamaki 预测道。

4 The first 5G networks came online in late 2019 in major cities around the world. That’s more or less in keeping with the pattern of major decadal upgrades in phone-network capabilities. To get a sense of how influential these upgrades can be, consider that the last big upgrade — from 3G to 4G networks around 2010 — drove the proliferation of phone apps that are now integral to our connected culture. “The move to 4G created the app economy, and made Google and Facebook what they are today,” says Kuoppamaki.
4 首批 5G 网络于 2019 年底在全球主要城市上线。这或多或少与电话网络功能重大十年升级的模式一致。要了解这些升级的影响力，请考虑一下上一次重大升级（2010 年左右从 3G 到 4G 网络）推动了手机应用程序的激增，这些应用程序现在已成为我们互联文化不可或缺的一部分。“向 4G 的转变创造了应用经济，并使 Google 和 Facebook 成为今天的成就，”Kuoppamaki 说。

5 The first applications to benefit from 5G will likely be those involving live-streaming video — that is, using a phone to record and transmit an event as it is happening. 5G speeds can cope with 8K image resolution, which entails quadruple the amount of information of ultra-high-definition 4K images and beyond even the capabilities of most TVs. The network also has enough extra bandwidth to simultaneously transmit multiple other video streams, allowing users to switch between camera angles at sporting events, for example, or to pan the viewpoint around 360 degrees.
5 首先受益于 5G 的应用可能是那些涉及实时流媒体视频的应用，即使用手机在事件发生时录制和传输事件。5G 速度可以应对 8K 图像分辨率 ，这需要将超高清 4K 图像的信息量增加四倍甚至超越了大多数电视的功能。该网络还有足够的额外带宽来同时传输多个其他视频流，例如，允许用户在体育赛事的摄像机角度之间切换，或者将视点平移 360 度。

6 Other applications certain to get early 5G upgrades include mobile gaming and virtual reality (VR) apps that embed goggle-wearing users in 3D images. These applications will benefit from another aspect of 5G networks. “There’s a misconception that 5G is only about higher speeds,” says Kuoppamaki. “Low latency is a big benefit, too, a more comprehensive, end-to-end measure of data speed than transmission speed.” Gaming and VR apps work best when the images change almost instantly in response to user input, whether it’s swiping on the screen, waving a hand or turning a head. The new 5G networks will reduce latency by 80 percent, providing a near immediate response.
6 其他肯定会获得早期 5G 升级的应用程序包括移动游戏和虚拟现实 （VR） 应用程序，这些应用程序将 佩戴护目镜的用户嵌入 3D 图像中。这些应用将受益于 5G 网络的另一个方面。“人们有一种误解，认为 5G 只是为了更高的速度，”Kuoppamaki 说。“低延迟也是一个很大的好处，它是比传输速度更全面的端到端数据速度衡量标准。”当图像几乎立即响应用户输入而变化时，无论是在屏幕上滑动 、挥手还是转头，游戏和 VR 应用程序都能发挥最佳效果。新的 5G 网络将延迟降低 80%，提供近乎即时的响应。

7 The speed and fast response of 5G networks will also affect the kit: VR goggles, for example, can be sleeker, lighter and less clunky, notes Kuoppamaki. That’s because today those goggles need to provide much of the processing power that turns raw data into actual images. But 5G networks can zip data back and forth quickly enough to mean that much of the processing can move to the cloud.
7 5G 网络的速度和快速响应也会影响套件： 例如，VR 护目镜可以更时尚、 更轻便、更不笨重，Kuoppamaki 指出。这是因为今天这些护目镜需要提供将原始数据转换为实际图像的大部分处理能力。但 5G 网络可以 足够快地来回压缩数据，这意味着大部分处理都可以转移到云端。

8 Closely related to VR is augmented reality (AR), where graphics and text are superimposed on real images. AR, too, will become widespread with 5G, and in many cases essential,  says Kuoppamaki. “Imagine you want to try a little home plumbing to change your faucet,” he says. “You could put on your goggles and let an augmented-reality app walk you through each step under the sink, while you look at your pipes.” 5G-charged VR and AR apps could literally add a new dimension to education and training in almost any domain.
8 与 VR 密切相关的是增强现实 （AR）， 其中图形和文本叠加在真实图像上。Kuoppamaki 说，AR 也将随着 5G 的普及而普及，而且在许多情况下是必不可少的 。“想象一下，你想尝试用一个小小的家用管道来更换你的水龙头，”他说。“你可以戴上护目镜，让增强现实应用程序引导你完成水槽下的每一步，同时你看着你的管道。”5G 驱动的 VR 和 AR 应用程序几乎可以为任何领域的教育和培训增加一个新的维度。

9 And, of course, there is the Internet of Things, which will surround us with many ‘smart’ items. Around the home, that could be tomato plants in the garden that can ask for water, roofs that warn of weaknesses after extreme weather, jackets that keep parents updated on a child’s location, trash cans that ask to be emptied, and milk cartons that point out expiration dates. In the streets, it’s a heads-up on open parking spaces, second-to-second data on surrounding traffic for driverless cars, local air-quality warnings, icy sidewalk alerts, and much more.
9 当然，物联网将用许多“智能”物品围绕着我们。在家里，这可能是花园里可以要求浇水的番茄植物、极端天气后警告弱点的屋顶、让父母了解孩子位置的最新情况的夹克、要求清空的垃圾桶以及指出有效期的牛奶盒。在街道上，它是开放停车位的提醒、无人驾驶汽车周围交通的秒对秒数据、当地空气质量警告、结冰的人行道警报等等。

10 “The Internet of Things will change the way we live and how we interact with the environment around us,” says Kuoppamaki.
10 “物联网将改变我们的生活方式以及我们与周围环境互动的方式，”Kuoppamaki 说。

11 Businesses will benefit, too. Industrial robots, drones and driverless trucks will be more responsive to obstacles and fast-changing conditions. Cables will be redundant, even for the most complex computer-controlled machines, making them easier to move around. Businesses will be free to reconfigure the factory floor in response to product changes or fluctuations in customer orders. “Today, it’s hard for factories to change quickly,” says Kuoppamaki. “If you can make equipment more mobile, you can reduce the time to market.” What’s more, he adds, sensors in the machinery will constantly feed remote AI software with the monitoring data it needs to self-adjust in response to variations in product quality, and to judge when the equipment requires preventive maintenance to avoid down-time and more expensive repairs.
11 企业也将受益。工业机器人、无人机和无人驾驶卡车将对障碍物和快速变化的条件做出更灵活的响应。即使对于最复杂的计算机控制的机器，电缆也将是多余的，这使得它们更容易移动。企业可以自由地重新配置工厂车间，以应对产品变化或客户订单的波动。“今天，工厂很难快速改变，”Kuoppamaki 说。“如果您可以提高设备的移动性，就可以缩短上市时间。”此外，他补充说，机器中的传感器将不断向远程 AI 软件提供所需的监控数据，以便根据产品质量的变化进行自我调整，并判断设备何时需要预防性维护，以避免停机和更昂贵的维修。

12 The 5G transformation won’t happen overnight, warns Kuoppamaki. The first wave of sophisticated applications are likely three or more years away. Cost may be a temporary barrier, too because currently, the only phones that can access 5G networks are top-of-the-line new models.
12 5G 转型不会在一夜之间发生，Kuoppamaki 警告说。第一波复杂应用程序可能在三年或更长时间后出现。成本也可能是一个暂时的障碍，因为目前唯一可以访问 5G 网络的手机是顶级新型号。

13 But the initial benefits, mostly those relating to speeding up existing applications, are already arriving.
13 但最初的好处（主要是与加速现有应用程序有关的好处）已经到来。

14 “Like all new technologies, adoption starts in the high end, and then makes its way down,” he says. “It will only take a few years before we see 5G everywhere.”
14 “与所有新技术一样，采用率从高端开始，然后逐渐下降，”他说。“我们只需要几年时间就能看到 5G 无处不在。”

Notes
笔记

Internet of Things (IOT)
物联网 （IOT）

A system of interrelated computing devices, mechanical and digital machines, objects, animals or people that are provided with unique identifiers ( UIDs ) and the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction.
一个由相互关联的计算设备、机械和数字机器、物体、动物或人组成的系统，它们具有唯一标识符 （ UID ），并且能够通过网络传输数据，而无需人与人或人与计算机的交互。

T-Mobile
T-移动

A multinational mobile phone operator. It is a subsidiary of German Telecom and belongs to the Freemove Union. T-Mobile operate GSM networks in Western Europe and the United States and participate in network operations in Eastern Europe and South-East Asia through financial means. The company has 109 million users and is one of the world's largest mobile phone companies.
一家跨国移动电话运营商。它是德国电信的子公司，隶属于 Freemove Union。T-Mobile 在西欧和美国运营 GSM 网络，并通过金融手段参与东欧和东南亚的网络运营。该公司拥有 1.09 亿用户，是世界上最大的手机公司之一。

8K image resolution 8K分辨率
8K 图像分辨率 8K 分辨率

ultra-high-definition 4K images超高清4K图像
ultra-high-definition 4K images 超高清 4K 图像

virtual reality (VR) 虚拟现实
Virtual Reality （VR） 虚拟现实

An artificial environment created with computer hardware and software and presented to the user in such a way that it appears and feels like a real environment.
使用计算机硬件和软件   创建的人工 环境，并以看起来和感觉像真实环境的方式呈现给用户。     

VR goggles VR眼镜即VR头显，虚拟现实头戴式显示设备

augmented reality (AR) 增强现实
增强现实 （AR） 增强现实

A type of virtual reality that aims to duplicate the world’s environment in a computer. An augmented reality system generates a composite view for the user that is the combination of the real scene viewed by the user and a virtual scene generated by the computer that augments the scene with additional information.
  一种旨在在计算机上 复制世界环境的虚拟现实 。增强现实系统为用户生成复合视图，该视图是用户查看的真实场景与计算机生成的虚拟场景的组合，该虚拟场景使用附加信息增强场景。

down-time停机时间；停工期

Unit Three
第三单元

Reading Materials
阅读材料

Passage 2
第 2 段

Qualcomm makes strides in 5G network development: Here’s what it means for you
Qualcomm 在 5G 网络开发方面取得长足进步：这对您意味着什么

By Christian de Looper October 21, 2020
By  克里斯蒂安·德·卢珀 October 21， 2020

1 Qualcomm wants to make 5G more accessible, more common, and faster. The company recently held its annual 5G Day event, where it made a few announcements related to the rollout of 5G, the continued development of 5G tech, and more.
1Qualcomm  希望让 5G 更易访问、更普遍、更快速。该公司最近举行了一年一度的 5G Day 活动，在那里它发布了一些与 5G 推出 、5G 技术的持续发展等相关的公告。

2 Of course, you might be wondering whether any of this really matters to you and how it will benefit the average smartphone user. Here’s a quick rundown of Qualcomm’s new 5G-related announcements, and what they could mean for you.
2 当然，您可能想知道这些 对您来说是否真的 重要，以及它将如何使普通智能手机用户受益。以下是高通与 5G 相关的新公告的简要  概述 ，以及它们对您意味着什么。

Qualcomm wants to help build 5G infrastructure
Qualcomm 希望帮助构建 5G 基础设施

3 Traditionally, Qualcomm has developed and manufactured chipsets and modems that can connect to 5G networks, but now it wants to play a bigger role in the actual infrastructure behind 5G. Specifically, the company is building Radio Access Network (RAN) chips, which are designed to be used in 5G base stations for your phone (or tablet, or computer) to connect.
3 传统上，高通开发和制造了可以连接到 5G 网络的芯片组和调制解调器，但现在它希望在 5G 背后的实际基础设施中发挥更大的作用。具体来说，该公司正在制造无线接入网络 （RAN） 芯片，这些芯片旨在用于  手机（或平板电脑、 或计算机）进行连接。

4 It’s important to note that Qualcomm won’t necessarily be directly competing with the likes of Huawei and Ericsson. Instead, it will supply those companies with the 5G chips and related software to power their infrastructure. That marks a shift for cell infrastructure, which has traditionally been built all by one company. Making 5G networks a little more modular also means that they could be more easily updated and developed without carriers having to deploy all-new infrastructure, but it remains to be seen if that will actually happen.
4 需要注意的是，  高通不一定会与华为和爱立信等公司直接竞争。相反，它将为这些公司提供 5G 芯片和相关软件，以支持他们的基础设施。这标志着蜂窝基础设施的转变，传统上由一家公司构建。使 5G 网络更加模块化也意味着它们可以更轻松地更新和开发，而无需运营商部署全新的基础设施，但这是否真的会发生还有待观察。

5 But what does that mean for you? Well, Qualcomm has been a leader in the 5G world for some time, and it entering this particular business could help make real-world 5G networks faster and more reliable. Unlike other companies, Qualcomm has expertise in the end-user device chipsets, too, so it knows exactly how to make them interoperate for the best performance. Qualcomm’s chips, of course, support the super-fast mmWave (millimeter-wave) networks, and the widespread Sub-6 networks, so if they become widespread, you may get much better mmWave support
5 但这对你有什么意义呢？好吧，高通一直是 5G 领域的领导者已经有一段时间了，它进入这项特定业务可以帮助使现实世界的 5G 网络更快、更可靠。与其他公司不同，Qualcomm 在最终用户设备芯片组方面也拥有专业知识，因此它确切地知道如何使它们互作以获得最佳性能。当然，Qualcomm 的芯片支持超高速 mmWave（毫米波）网络和广泛的 Sub-6 网络，因此如果它们得到广泛应用，您可能会获得更好的 mmWave 支持.

There’s a new record for fastest 5G speeds
最快的 5G 速度创下新纪录

6 Qualcomm also announced that in partnership with Verizon and Ericsson, it achieved a peak 5G speed of a whopping 5.06Gbps. The speed was achieved with a bunch of fancy tech on a mmWave network and using what’s called carrier aggregation, which combines multiple channels to make for faster speeds.
6 高通还宣布，通过与 Verizon 和 Ericsson 合作 ，它实现了  高达 5.06Gbps 的 5G 峰值速度   。这种速度是通过毫米波网络上的一系列花哨技术实现的，并使用了所谓的载波聚合 ，该聚合结合了多个通道以实现更快的速度。

7 According to Qualcomm, 5G will eventually reach speeds of 10Gbps, but that’s just talk right now — we’ll have to wait and see if that happens and if it’s accessible.
7 根据高通的说法，5G 最终将达到 10Gbps 的速度，但这只是现在的谈话——我们将不得不等待，看看这是否会发生，以及它是否可以访问。

8 It’s important to be very clear about how Qualcomm achieved this huge peak speed — in a tightly controlled lab environment. In other words, carriers aren’t going to be able to flick a switch and turn on 5Gbps speeds anytime soon.
8 重要的是要非常清楚 Qualcomm 是如何在严格控制的实验室环境中实现如此巨大的峰值速度的。换句话说，运营商将无法在短期内拨动开关并打开 5Gbps 速度。

9 But that doesn’t mean that it won’t benefit you. As companies like Qualcomm continue to work on 5G development, and as the tech gets better and better it will eventually make its way to the real world. When it does, you likely won’t get 5Gbps, considering things like distance, obstacles, and the number of people using the same cell tower as you. But you should still get faster speeds than you did before, and hopefully, faster speeds than you’ll get on even the best 4G LTE networks.
9 但这并不意味着它不会对你有所益处。随着高通等公司继续致力于 5G 开发，随着技术越来越好，它最终将 进入现实世界。当它出现时，考虑到距离、障碍物和与您使用同一手机信号塔的人数等因素，您可能无法获得 5Gbps。但是您仍然应该获得比以前更快的速度，并且希望比您在最好的 4G LTE 网络上获得的速度更快。

Notes
笔记

Qualcomm高通公司

Founded in 1985 and headquartered in San Diego, California, USA, Qualcomm is the world's leading wireless technology innovator and has changed the way the world connects, computes and communicates. Its invention opened the era of mobile interconnection.
Qualcomm 成立于 1985 年 ， 总部位于美国加利福尼亚州圣地亚哥，是世界领先的无线技术创新者 ，改变了世界连接、计算和通信的方式。 它的发明开启了 移动互联时代 。

Radio Access Network (RAN) 无线电接入网
Radio Access Network （RAN） 无线电接入网

A part of a mobile communication system and the realization of radio access technology. It exists on a device, a mobile phone, a computer, or any remotely controlled machine with a core network and provides a communication connection between the two.
移动通信系统的一部分和无线接入技术的实现。它存在于设备、 手机、 计算机或任何具有核心网络 的遥控机器上， 并在两者之间提供通信连接。

mmWave (millimeter-wave)毫米波
mmWave （millimeter-wave） 毫米波

Millimeter wave is an electromagnetic wave between microwave and light wave. Usually millimeter wave band refers to 30 GHz~300 GHz, corresponding wavelength is 1 mmGHz~10 mm.. The millimeter wave communication refers to the communication with millimeter wave as the carrier of information transmission.
毫米波是介于微波和光波之间的电磁波。通常毫米波段是指 30 GHz~300 GHz，对应的波长为 1 mmGHz~10 mm。 米伊利米波通信是指以毫米波为载体进行信息传输的通信。

Sub-6
6 岁以下

The global 5 G network frequency band is mainly divided into two major ranges: Sub-6GHz and millimeter wave. At present, the main use of this band in China is Sub-6GHz, which has strong signal penetration but slower speed of data transmission than that of millimeter wave
全球 5G 网络频段主要分为 Sub-6GHz 和毫米波两大范围。目前，该频段在国内的主要用途是 Sub-6GHz，信号穿透力强，但数据传输速度比毫米波慢.

Verizon威瑞森电信

The largest local telephone company and the largest wireless communications company in the United States
美国最大的本地电话公司和最大的无线通信公司.

Ericsson爱立信公司

Founded in 1876 in Stockholm, Sweden., Ericsson is the world's largest provider of mobile communications networks
爱立信于 1876 年在瑞典斯德哥尔摩成立，是全球最大的移动通信网络提供商.

carrier aggregation载波聚合
载波聚合

The aggregation of two or more carrier units (Component Carrier) to support a larger transmission bandwidth (up to 100 MHz).
两个或多个载波单元（分量载波）的聚合，以支持更大的传输带宽（高达 100 MHz）。

LTE (Long Term Evolution)长期演进技术
LTE （Long Term Evolution） 长期演进技术

LTE (Long Term Evolution) project is an evolution of 3G, a transition between 3 G and 4 technologies, and a global standard of 3.9 G, which improves and enhances 3G air access technology by using OFDM and MIMO as the sole criteria for its wireless network evolution.
LTE（Long Term Evolution）项目是 3G 的演进，是 3G 和 4 技术之间的过渡，是 3.9 G 的全球标准 ， 以 OFDM 和 MIMO 作为其无线网络演进的唯一标准 ， 改进和增强了 3G 空中接入技术 。

Reading Material (982 words):
阅读材料 （982 字）：

Designing customized “brains” for robots
为机器人设计定制的“大脑”

A new system devises hardware architectures to hasten robots’ response time
新系统设计硬件架构以加快机器人的响应时间

Daniel Ackerman | MIT News Office
丹尼尔·阿克曼  麻省理工学院新闻办公室

Publication Date: January 21, 2021
出版日期：2021 年 1 月 21 日

Contemporary robots can move quickly. “The motors are fast, and they’re powerful,” says Sabrina Neuman.
现代机器人  可以  快速移动。“电机速度快，而且功能强大，”Sabrina Neuman 说。

Yet in complex situations, like interactions with people, robots often don’t move quickly. “The hang up is what’s going on in the robot’s head,” she adds.
然而，在复杂情况下，例如与人的互动，机器人通常  不会  快速移动。“ 挂断是机器人脑子里发生的事情，”她补充道。

Perceiving stimuli and calculating a response takes a “boatload of computation,” which limits reaction time, says Neuman, who recently graduated with a PhD from the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL). Neuman has found a way to fight this mismatch between a robot’s “mind” and body. The method, called robomorphic computing, uses a robot’s physical layout and intended applications to generate a customized computer chip that minimizes the robot’s response time.
最近从麻省理工学院计算机科学与人工智能实验室 （CSAIL） 获得博士学位的 Neuman 说，感知刺激和计算反应需要“ 大量的计算”，这限制了反应时间。Neuman 找到了一种对抗机器人“思想”和身体之间不匹配的方法。这种方法称为机器人拟物计算，它使用机器人的物理布局和预期应用来生成定制的计算机芯片，以最大限度地减少机器人的响应时间。

The advance could fuel a variety of robotics applications, including, potentially, frontline medical care of contagious patients. “It would be fantastic if we could have robots that could help reduce risk for patients and hospital workers,” says Neuman.
这一进步可能会推动各种机器人应用，包括潜在的传染性患者的一线医疗护理 。“如果我们能拥有可以帮助降低患者和医院工作人员风险的机器人，那就太棒了，”Neuman 说。

Neuman will present the research at this April’s International Conference on Architectural Support for Programming Languages and Operating Systems. MIT co-authors include graduate student Thomas Bourgeat and Srini Devadas, the Edwin Sibley Webster Professor of Electrical Engineering and Neuman’s PhD advisor. Other co-authors include Brian Plancher, Thierry Tambe, and Vijay Janapa Reddi, all of Harvard University. Neuman is now a postdoctoral NSF Computing Innovation Fellow at Harvard’s School of Engineering and Applied Sciences.
Neuman 将在今年 4 月的编程语言和作系统架构支持国际会议上展示这项研究。麻省理工学院的合著者包括研究生 Thomas Bourgeat 和 Srini Devadas，后者是 Edwin Sibley Webster 电气工程教授和 Neuman 的博士生导师。其他合著者包括哈佛大学的 Brian Plancher、Thierry Tambe 和 Vijay Janapa Reddi。Neuman 现在是 哈佛大学工程与应用科学学院的 NSF 计算创新博士后研究员 。

There are three main steps in a robot’s operation, according to Neuman. The first is perception, which includes gathering data using sensors or cameras. The second is mapping and localization: “Based on what they’ve seen, they have to construct a map of the world around them and then localize themselves within that map,” says Neuman. The third step is motion planning and control — in other words, plotting a course of action.
根据 Neuman 的说法，机器人的作有三个主要步骤。首先是感知，包括使用传感器或摄像头收集数据。第二个是地图绘制和定位：“根据他们所看到的，他们必须构建一张周围世界的地图，然后在该地图中定位自己，”Neuman 说。第三步是运动规划和控制 — 换句话说，绘制一个行动方案。

These steps can take time and an awful lot of computing power. “For robots to be deployed into the field and safely operate in dynamic environments around humans, they need to be able to think and react very quickly,” says Plancher. “Current algorithms cannot be run on current CPU hardware fast enough.”
这些步骤可能需要时间和大量的计算能力。“为了让机器人部署到现场并在人类周围的动态环境中安全运行，它们需要能够非常快速地思考和反应，”Plancher 说。“当前的算法无法在当前的 CPU 硬件上运行得足够快。”

Neuman adds that researchers have been investigating better algorithms, but she thinks software improvements alone aren’t the answer. “What’s relatively new is the idea that you might also explore better hardware.” That means moving beyond a standard-issue CPU processing chip that comprises a robot’s brain — with the help of hardware acceleration.
Neuman 补充说，研究人员一直在研究更好的算法，但她认为仅靠软件改进并不是答案。“相对较新的想法是，你也可以探索更好的硬件。”这意味着在 硬件加速的帮助下，超越了构成机器人大脑的标准 CPU 处理芯片。

Hardware acceleration refers to the use of a specialized hardware unit to perform certain computing tasks more efficiently. A commonly used hardware accelerator is the graphics processing unit (GPU), a chip specialized for parallel processing. These devices are handy for graphics because their parallel structure allows them to simultaneously process thousands of pixels. “A GPU is not the best at everything, but it’s the best at what it’s built for,” says Neuman. “You get higher performance for a particular application.” Most robots are designed with an intended set of applications and could therefore benefit from hardware acceleration. That’s why Neuman’s team developed robomorphic computing.
硬件加速是指使用专用硬件单元来更高效地执行某些计算任务。常用的硬件加速器是图形处理单元 （GPU），这是一种专门用于并行处理的芯片。这些设备对于图形来说很方便 ， 因为它们的并行结构允许它们同时处理数千个像素 。“GPU 并非在所有方面都是最好的，但它在它的构建目的方面是最好的，”Neuman 说。“您可以为特定应用程序获得更高的性能。”大多数机器人都是为一组预期的应用程序而设计的，因此可以从硬件加速中受益。这就是 Neuman 的团队开发机器人拟人计算的原因。

The system creates a customized hardware design to best serve a particular robot’s computing needs. The user inputs the parameters of a robot, like its limb layout and how its various joints can move. Neuman’s system translates these physical properties into mathematical matrices. These matrices are “sparse,” meaning they contain many zero values that roughly correspond to movements that are impossible given a robot’s particular anatomy. (Similarly, your arm’s movements are limited because it can only bend at certain joints — it’s not an infinitely pliable spaghetti noodle.)
该系统会创建一个定制的硬件设计，以最好地满足特定机器人的计算需求。用户输入机器人的参数，例如其肢体布局以及各种关节的移动方式。Neuman 的系统将这些物理性质转换为数学矩阵。这些矩阵是“ 稀疏的 ”，这意味着它们包含许多零值，这些值大致对应于给定机器人特定解剖结构不可能的运动。（同样，你的手臂的运动是有限的，因为它只能在某些关节处弯曲——它不是无限的 柔韧的意大利面条。

The system then designs a hardware architecture specialized to run calculations only on the non-zero values in the matrices. The resulting chip design is therefore tailored to maximize efficiency for the robot’s computing needs. And that customization paid off in testing.
然后，系统设计一个硬件架构，专门用于仅对矩阵中的非零值运行计算。因此，由此产生的芯片设计经过定制 ，可以最大限度地提高机器人计算需求的效率。这种定制 在测试中得到了回报 。

Hardware architecture designed using this method for a particular application outperformed off-the-shelf CPU and GPU units. While Neuman’s team didn’t fabricate a specialized chip from scratch, they programmed a customizable field-programmable gate array (FPGA) chip according to their system’s suggestions. Despite operating at a slower clock rate, that chip performed eight times faster than the CPU and 86 times faster than the GPU.
使用此方法为特定应用程序设计的硬件架构优于现成的 CPU 和 GPU 单元。虽然 Neuman 的团队没有从头开始制造专用芯片，但他们根据系统的建议对可定制的现场可编程门阵列 （FPGA） 芯片进行了编程。尽管以较慢的时钟速率运行 ，但该芯片的性能比 CPU 快 8 倍，比 GPU 快 86 倍。

“I was thrilled with those results,” says Neuman. “Even though we were hamstrung by the lower clock speed, we made up for it by just being more efficient.”
“我对这些结果感到非常兴奋，”Neuman 说。“尽管我们 受到较低时钟速度的阻碍，但我们通过提高效率来弥补。”

Plancher sees widespread potential for robomorphic computing. “Ideally we can eventually fabricate a custom motion-planning chip for every robot, allowing them to quickly compute safe and efficient motions,” he says. “I wouldn’t be surprised if 20 years from now every robot had a handful of custom computer chips powering it, and this could be one of them.” Neuman adds that robomorphic computing might allow robots to relieve humans of risk in a range of settings, such as caring for covid-19 patients or manipulating heavy objects.
Plancher 看到了机器人计算的广泛潜力。“理想情况下，我们最终可以为每个机器人制造一个定制的运动规划芯片，使它们能够快速计算出安全高效的运动，”他说。“如果 20 年后每个机器人都有少量定制计算机芯片为其提供动力，我不会感到惊讶，这可能是其中之一。”Neuman 补充说，机器人拟物计算可能允许机器人在各种环境中减轻人类的风险，例如照顾 covid-19 患者或纵重物。

“This work is exciting because it shows how specialized circuit designs can be used to accelerate a core component of robot control,” says Robin Deits, a robotics engineer at Boston Dynamics who was not involved in the research. “Software performance is crucial for robotics because the real world never waits around for the robot to finish thinking.” He adds that Neuman’s advance could enable robots to think faster, “unlocking exciting behaviors that previously would be too computationally difficult.”
“这项工作令人兴奋，因为它展示了如何使用专门的电路设计来加速机器人控制的核心组件，”波士顿动力公司（Boston Dynamics）的机器人工程师罗宾·戴茨（Robin Deits）说，他没有参与这项研究。“软件性能对于机器人技术至关重要，因为现实世界永远不会等待机器人完成思考。”“他补充说，Neuman 的进步可以使机器人更快地思考，” 解锁以前计算难度太大的令人兴奋的行为”。

Neuman next plans to automate the entire system of robomorphic computing. Users will simply drag and drop their robot’s parameters, and “out the other end comes the hardware description. I think that’s the thing that’ll push it over the edge and make it really useful.”
Neuman 接下来计划实现整个机器人拟态计算系统的自动化。用户只需拖放机器人的参数，“另一端是硬件描述。我认为这就是将它推向边缘并使其真正有用的东西。

This research was funded by the National Science Foundation, the Computing Research Agency, the CIFellows Project, and the Defense Advanced Research Projects Agency.
这项研究由美国国家科学基金会、计算研究局、CIFellows 项目和国防高级研究计划局资助。

Words and expressions:
单词和表达式：

hang up：搁置；悬挂

stimuli：刺激
刺激 ：刺激

boatload：一条船的货物；大量

robomorphic：机器人形态的

contagious：传染的

fellow：研究员

algorithms ['ælɡərɪðəm]：算法
algorithms ['ælɡərɪðəm]： 算法

standard-issue：[军]常规的
standard-issue：[ 军 ] 常规的

graphics processing unit, GPU：图形处理器
图形处理单元， GPU： 图形处理器

handy：方便的；手边的

pixels：像素
像素 ： 像素

sparse：稀少的；稀疏的

pliable：易曲折的；柔软的

tailored：特制的；合身的

paid off：付清； 得到好处/回报

off-the-shelf：成品的；现成的

gate array：门数组，门阵列

clock rate：时钟速率

hamstrung：残废的；做不了的（hamstring的过去式和过去分词形式）

custom motion-planning： 定做的/定制的移动规划

unlock：开锁；开启；揭开

drag and drop：拖放
拖放 ： 拖放

CIFellows Project：Computing Innovation Fellows Project，计算创新研究员项目

Reading comprehension questions
阅读理解题

1. What slows down the response time of robots in complex situations?
1. 在复杂情况下 ， 什么会减慢机器人的响应时间 ？

2. What is the way Neuman has found to fight the mismatch between a robot’s “mind” and body?
2. Neuman 发现有什么方法可以对抗机器人的“思想”和身体之间的不匹配 ？

3. What are major steps in a robot’s operation?
3. 机器人作的主要步骤有哪些？

4. What could be widespread potential for robomorphic computing?
4. 机器人计算的广泛潜力是什么 ？

Passage 1
第 1 段

Researchers in the labs of Christopher Bates, an assistant professor of materials at UC Santa Barbara, and Michael Chabinyc, a professor of materials and chair of the department, have teamed to develop the first 3D-printable "bottlebrush" elastomer[¹] . The new material results in printed objects that have unusual softness and elasticity -- mechanical properties that closely resemble those of human tissue.
加州大学圣巴巴拉分校材料助理教授 Christopher Bates 和材料教授兼系主任 Michael Chabinyc 实验室的研究人员合作开发了第一个可 3D 打印的“bottlebrush” 弹性体 [¹]。 这种新材料使打印物体具有不寻常的柔软度和弹性——机械特性与人体组织的机械特性非常相似。

Conventional elastomers, i.e. rubbers, are stiffer than many biological tissues. That's due to the size and shape of their constituent polymers[²] , which are long, linear molecules that easily entangle like cooked spaghetti. In contrast, bottlebrush polymers have additional polymers attached to the linear backbone, leading to a structure more akin to a bottle brush you might find in your kitchen. The bottlebrush polymer structure imparts the ability to form extremely soft elastomers.
传统的弹性体，即橡胶，比许多生物组织更坚硬。这是由于它们的组成聚合物的大小和形状 [²] ，这些聚合物是长而线性的分子，很容易像煮熟的意大利面一样缠结。相比之下，bottlebrush 聚合物具有连接到线性主链的额外聚合物，导致其结构更类似于您在厨房中可能找到的瓶刷。瓶刷聚合物结构赋予了形成极其柔软的弹性体的能力。

The ability to 3D-print bottlebrush elastomers makes it possible to leverage these unique mechanical properties in applications that require careful control over the dimensions of objects ranging from biomimetic[³] tissue to high-sensitivity electronic devices, such as touch pads, sensors and actuators.
3D 打印瓶刷弹性体的能力使其能够在需要仔细控制物体尺寸的应用中利用这些独特的机械特性，从仿生[3] 组织到高灵敏度电子设备，如触摸板、传感器和执行器。

Two postdoctoral researchers -- Renxuan Xie and Sanjoy Mukherjee -- played key roles in developing the new material. Their findings were published in the journal Science Advances.
两名博士后研究人员 Renxuan Xie 和 Sanjoy Mukherjee 在开发这种新材料方面发挥了关键作用。他们的研究结果发表在《科学进展》（Science Advances）杂志 上 。

Xie's and Mukherjee's key discovery involves the self-assembly of bottlebrush polymers at the nanometer length scale, which causes a solid-to-liquid transition in response to applied pressure. This material is categorized as a yield-stress fluid[⁴], meaning it begins as a semi-soft solid that holds its shape, like butter or toothpaste, but when sufficient pressure is applied, it liquefies and can be squeezed through a syringe. The team exploits this property to create inks in a 3D-printing process called direct ink writing (DIW).
Xie 和 Mukherjee 的关键发现涉及纳米级瓶刷聚合物的自组装，这会响应施加的压力导致固液转变 。这种材料被归类为屈服应力流体[⁴]，这意味着它最初是一种半软固体，可以保持其形状 ，就像黄油或牙膏一样，但当施加足够的压力时，它会液化并可以通过注射器挤压。 该团队利用这一特性，在称为直接墨水写入 （DIW） 的 3D 打印过程中创建墨水。

The researchers can tune the material to flow under various amounts of pressure to match the desired processing conditions. "For instance, maybe you want the polymer to hold its shape under a different level of stress, such as when vibration is present," says Xie. "Our material can hold its shape for hours. That's important, because if the material sags[⁵] during printing, the printed part will have poor structural stability."
研究人员可以调整材料在不同压力下的流动，以匹配所需的加工条件。“例如，也许您希望聚合物在不同水平的应力下保持其形状，例如当存在振动时，”Xie 说。“我们的材料可以保持其形状数小时。这很重要，因为如果材料在打印过程中下垂 [⁵]，打印部件的结构稳定性会很差。

Once the object is printed, UV light is shined onto it to activate crosslinkers[⁶] that Mukherjee synthesized and included as a part of the ink formulation. The crosslinkers can link up nearby bottlebrush polymers, resulting in a super-soft elastomer. At that point, the material becomes a permanent solid -- it will no longer liquefy[⁷] under pressure -- and exhibits extraordinary properties.
打印物体后，紫外线照射到其上以激活交联剂 [⁶]，Mukherjee 合成并作为油墨配方的一部分。交联剂可以连接附近的 bottlebrush 聚合物， 从而产生超柔软的弹性体。此时，材料会变成永久性固体 -- 它将不再在压力下液化 [⁷] -- 并表现出非凡的特性 。

"We start with long polymers that are not crosslinked," said Xie. "That allows them to flow like a fluid. But, after you shine the light on them, the small molecules between the polymer chains react and are linked together into a network, so you have a solid, an elastomer that, when stretched, will return to its original shape."
“我们从不交联的长聚合物开始，”Xie 说。“这使它们能够像流体一样流动。但是，在你把光照射到它们身上后，聚合物链之间的小分子会发生反应并连接在一起形成一个网络，所以你就得到了一个固体，一种弹性体，当拉伸时，它会恢复到原来的形状。

The softness of a material is measured in terms of its modulus[⁸] , and for most elastomers, it is rather high, meaning their stiffness and elasticity are similar to those of a rubber band. "The modulus of our material is a thousand times smaller than that of a rubber band," Xie notes. "It is super-soft -- it feels very much like human tissue -- and very stretchy. It can stretch about three to four times its length."
材料的柔软度是用模量来衡量的 [⁸] ，对于大多数弹性体来说，它相当高，这意味着它们的刚度和弹性与橡皮筋相似。“我们材料的模量比橡皮筋的模量小一千倍，”Xie 指出。“它超级柔软——感觉很像人体组织——而且非常有弹性。它可以伸展大约是其长度的三到四倍。

An Accidental Ink (how this material is developed)
意外墨水（这种材料是如何开发的）

Mukherjee discovered the material by accident, while trying to develop a material for a different project, one that would increase the amount of charge that can be stored by an actuator[⁹]. When the elastomer came to Xie for characterization, he knew immediately that it was special. "I could see right away that it was different, because it could hold its shape so well," he recalled.
Mukherjee 在尝试为另一个项目开发一种材料时偶然发现了这种材料，这种材料会增加执行器可以存储的电荷量 [⁹]。 当弹性体找到 Xie 进行表征时，他立即知道它很特别。“我立刻就看出它不同了，因为它可以很好地保持形状，”他回忆道。

"When we saw this really well-defined yield stress, it dawned on everyone collectively that we could 3D-print it," Bates said, "and that would be cool, because none of the 3D-printable materials we know of have this super-soft property."
“当我们看到这种真正明确的屈服应力时， 每个人都意识到我们可以 3D 打印它，”Bates 说，“那会很酷，因为我们所知道的 3D 打印材料都没有这种超软的特性。

Bottlebrush polymers have been around for more than twenty years. But, Bates said, "The field has exploded in the past ten years thanks to advances in synthetic chemistry that provide exquisite control over the size and shape of these unique molecules.
Bottlebrush 聚合物已经存在了 20 多年。但是，Bates 说：“由于合成化学的进步，该领域在过去十年中呈爆炸式增长，这些化学可以精确控制这些独特分子的大小和形状。

"These super-soft elastomers might be applicable as implants[¹⁰]," he added. "You may be able to reduce inflammation and rejection by the body if the mechanical properties of an implant match native tissue."
“这些超柔软的弹性体可能适用于植入物 [¹⁰]，”他补充道。“如果植入物的机械特性与天然组织相匹配，您也许能够减少身体的炎症和排斥反应。”

Another important element of the new material is that it is pure polymer, Chabinyc noted.
Chabinyc 指出 ，新材料的另一个重要元素是它是纯聚合物 。

"There's no water or other solvent in them to artificially make them softer," he said.
“它们中没有水或其他溶剂来人为地使它们变软，”他说。

To understand the importance of having no water in the polymer, it's helpful to think of Jell-O, which is mostly water and can hold its shape, but only as long as the water remains inside. "If the water went away, then you'd just have a shapeless pile of material," said Chabinyc. "With a conventional polymer, you must figure out how to keep the right amount of water in it to maintain its structure, but this new material is all solid, so it will never change."
要了解聚合物中没有水的重要性，考虑一下果冻会很有帮助，它主要是水并且可以保持其形状，但前提是水留在内部。“如果水消失了，那么你就会得到一堆无形的材料，”Chabinyc 说。“使用传统聚合物时，必须弄清楚如何在其中保持适量的水以保持其结构 ，但这种新材料是全固体，因此永远不会改变。”

Moreover, the new material can be 3D-printed and processed without solvent, which is also unusual. "People often add solvent to liquify a solid so that it can be squeezed out of a nozzle," said Xie, "but if you add solvent, it has to evaporate after printing causing the object to change its shape or crack."
此外， 这种新材料可以在没有溶剂的情况下进行 3D 打印和加工，这也是不寻常的。“人们经常添加溶剂来液化固体，以便它可以从喷嘴中挤出，”Xie 说，“但如果你添加溶剂，它在打印后必须蒸发，导致物体改变形状或破裂。

Mukherjee added, "We wanted the material and the printing process to be as clean and as easy as possible, so we played a chemistry trick with solubility and self-assembly, which enabled the solvent-free process. The fact that we don't use solvent is a tremendous advantage."
Mukherjee 补充道：“ 我们希望材料和打印过程尽可能干净和简单，因此我们在溶解性和自组装方面玩了个化学技巧 ，从而实现了无溶剂工艺。我们不使用溶剂这一事实是一个巨大的优势。

Story Source:
故事来源：

Materials provided by University of California - Santa Barbara. Original written by James Badham. Note: Content may be edited for style and length.
材料  由  加州大学圣巴巴拉分校提供 。原文由 James Badham 撰写。  注意：内容可能会因风格和长度而进行编辑。

Journal Reference:
期刊参考 ：

Renxuan Xie, Sanjoy Mukherjee, Adam E. Levi, Veronica G. Reynolds, Hengbin Wang, Michael L. Chabinyc, Christopher M. Bates. Room temperature 3D printing of super-soft and solvent-free elastomers. Science Advances, 2020; 6 (46): eabc6900 DOI: 10.1126/sciadv.abc6900
Renxuan Xie， Sanjoy Mukherjee， Adam E. Levi， Veronica G. Reynolds， Hengbin Wang， Michael L. Chabinyc， Christopher M. Bates.  超柔软和无溶剂弹性体的室温 3D 打印 。  科学进展 ， 2020;6 （46）： eabc6900 DOI： 10.1126/sciadv.abc6900

Passage2

CHEMISTRY
化学

Chemists are reimagining recycling to keep plastics out of landfills
化学家正在重新构想回收利用，以防止塑料进入垃圾填埋场

Too much of today's plastic is impossible to recycle
当今太多的塑料是无法回收的

A lot of plastic goes to landfills because the material is too difficult to recycle into useful new products.
许多塑料被送往垃圾填埋场，因为这种材料太难回收成有用的新产品。

ABDUL RAHEEM MOHAMED/EYEEM/GETTY IMAGES
阿卜杜勒·拉希姆·穆罕默德/EYEEM/盖蒂图片社

By Maria Temming
作者 ：Maria Temming

JANUARY 27, 2021 AT 10:19 AM
1月 27， 2021 10：19 上午

It feels good to recycle. There’s a certain sense of accomplishment that comes from dutifully sorting soda bottles, plastic bags and yogurt cups from the rest of the garbage. The more plastic you put in that blue bin, the more you’re keeping out of landfills and the oceans, right?
回收的感觉很好。尽职尽责地将汽水瓶、塑料袋和酸奶杯从其余垃圾中分类，会带来一定的成就感。你放入蓝色垃圾桶的塑料越多，你就越能远离垃圾填埋场和海洋，对吧？

Wrong. No matter how meticulous you are in cleaning and separating your plastics, most end up in the trash heap anyway.
错。无论您在清洁和分离塑料方面多么细致，大多数塑料最终都会被扔进垃圾堆。

Take flexible food packages. Those films contain several layers of different plastics. Because each plastic has to be recycled separately, those films are not recyclable. Grocery bags and shrink wrap are too flimsy, prone to getting tangled up with other materials on a conveyor belt. The polypropylene[¹¹]in yogurt cups and other items doesn’t usually get recycled either; recycling a hodgepodge[¹²] of polypropylene produces a dark, smelly plastic that few manufacturers will use.
以灵活的食品包装为例。这些薄膜包含几层不同的塑料。由于每种塑料都必须单独回收，因此这些薄膜不可回收。购物袋和收缩包装太脆弱， 容易与传送带上的其他材料缠结。 酸奶杯和其他物品中的聚丙烯 [¹¹] 通常也不会被回收;回收大杂烩 [¹²] 的聚丙烯会产生一种深色、有臭味的塑料，很少有制造商会使用。

Only two kinds of plastic are commonly recycled in the United States: the kind in plastic soda bottles, polyethylene terephthalate [¹³], or PET[¹⁴]; and the plastic found in milk jugs and detergent containers — high-density polyethylene, or HDPE.
在美国，通常只回收两种塑料 ：塑料汽水瓶中的塑料， 聚对苯二甲酸乙二醇酯 [¹³]，或 PET[¹⁴];以及牛奶罐和洗涤剂容器中的塑料——高密度聚乙烯，或 HDPE。

Together, those plastics make up only about a quarter of the world’s plastic trash, researchers reported in 2017 in Science Advances. And when those plastics are recycled, they aren’t good for much. Melting plastic down to recycle changes its consistency, so PET from bottles has to be mixed with brand-new plastic to make a sturdy final product. Recycling a mix of multicolored HDPE pieces creates a dark plastic good only for making products like park benches and waste bins, in which properties like color don’t matter much.
研究人员在 2017 年发表在《 科学进展》（Science Advances） 杂志上 报告说 ， 这些塑料加起来仅占全球塑料垃圾的四分之一左右。  当这些塑料被回收时，它们并没有多大用处。将塑料熔化以回收会改变其稠度，因此瓶子中的 PET 必须与全新的塑料混合，才能制成坚固的最终产品。 回收五颜六色的 HDPE 碎片混合物会产生一种深色塑料，仅用于制造公园长椅和垃圾桶等产品，在这些产品中，颜色等特性并不重要。

The difficulties of recycling plastic into anything manufacturers want to use is a big reason why the world is littered with so much plastic waste, says Eric Beckman, a chemical engineer at the University of Pittsburgh. In 2018 alone, the United States landfilled 27 million tons of plastic and recycled a mere 3 million, according to the U.S. Environmental Protection Agency. Low recycling rates aren’t just a problem in the United States. Of the 6.3 billion tons of plastic that have been discarded around the world, only about 9 percent has gotten recycled. Another 12 percent has been burned, and almost 80 percent has piled up on land or in waterways.
匹兹堡大学（University of Pittsburgh）的化学工程师埃里克·贝克曼（Eric Beckman）说 ， 将塑料回收成制造商想要使用的任何东西的困难是全世界到处都是塑料垃圾的一个重要原因。根据美国环境保护署的数据， 仅在 2018 年，美国  就填埋了 2700 万吨塑料 ，回收了仅 300 万吨塑料 。低回收率不仅仅是美国的问题。在全球丢弃的 63 亿吨塑料中，只有大约 9 % 得到了回收利用。另有 12% 的垃圾被烧毁，近 80% 的垃圾堆积在陆地或水道中。

Good news/bad news 
好消息/坏消息

The amount of plastic recycled in the United States has increased over the last few decades — but those levels still pale in comparison with the amount of plastic that goes into landfills.
在过去的几十年里，美国的塑料回收量有所增加，但与进入垃圾填埋场的塑料数量相比 ，这些水平仍然相形见绌 。

Plastic waste management, 1960–2018
塑料废物管理，1960-2018 年

SOURCE: EPA
来源：EPA

With plastic collecting everywhere from the top of Mount Everest [¹⁵]to the bottom of the Mariana Trench[¹⁶], there’s an urgent need to reduce the amount of plastic that gets thrown away (SN: 1/16/21, p. 5). Some people propose replacing plastics with biodegradable materials, but those replacements are generally not as strong or cheap to make as plastics (SN: 6/22/19, p. 18). Since, realistically, plastic is not going away any time soon, chemists who understand the ins and outs of all this pesky [¹⁷]plastic are working to make it easier to recycle and turn into higher-quality material that’s useful for more things.
从珠穆朗玛峰的顶部 [¹⁵] 到马里亚纳海沟 [¹⁶] 的底部 ，到处都是塑料 ，  迫切需要减少被丢弃的塑料  数量（SN：1/16/21，第 5 页 ）。有些人提议  用可生物降解的材料代替塑料 ，但这些替代品通常不如塑料坚固或制造成本低（SN：6/22/19，第 18 页 ）。 由于实际上，塑料不会很快消失，因此了解所有这些讨厌的 [¹⁷] 塑料的来龙去脉的化学家正在努力使其更容易回收并转化为可用于更多事物的更高质量的材料。

“There’s not going to be a single technology that’s going to be the answer,” says Ed Daniels, senior project manager at the REMADE Institute in West Henrietta, N.Y., which funds research into new recycling techniques. Some projects are on the brink of breaking into industry; others are still just promising lab experiments. But all are focused on designing a future where any plastic that ends up in the recycling bin can have a second and third life in a new product.
“不会有单一的技术会成为答案，”纽约州西亨利埃塔的 REMADE 研究所的高级项目经理 Ed Daniels 说，该研究所为新回收技术的研究提供资金。一些项目即将进入工业界;其他项目仍然只是有前途的实验室实验。但所有公司都专注于设计一个未来，让任何最终进入回收箱的塑料都可以在新产品中获得第二次和第三次生命。

窗体底端

Picking plastics apart
将塑料分开

One of the biggest bottlenecks in plastic recycling is that every material has to get processed separately. “Most plastics are like oil and water,” says chemist Geoffrey Coates of Cornell University. They just don’t mix. Take, for example, a polyethylene detergent jug and its polypropylene cap. “If you melt those down, and I make a bottle out of that, and I squeeze it, it would basically crack down the side,” Coates says. “It’s crazy brittle. Totally worthless.”
塑料回收的最大瓶颈之一是每种材料都必须单独加工。“ 大多数塑料就像油和水一样，”康奈尔大学的化学家杰弗里·科茨 （Geoffrey Coates） 说。他们就是不混在一起。以聚乙烯洗涤剂壶及其聚丙烯瓶盖为例。“如果你把它们融化，我用它做一个瓶子，然后挤压它，它基本上会从侧面破裂，”Coates 说。“它太脆弱了。完全一文不值。

That’s why the first destination for plastic recyclables is a material recovery facility, where people and machines do the sorting. Separated plastics can then be washed, shredded, melted and remolded. The system works well for simple items like soda bottles and milk jugs. But not for items like deodorant [¹⁸]containers — where the bottle, crank and cap could all be made of different kinds of plastic. Food packaging films that contain several layers of different plastic are particularly tricky to take apart. Every year, 100 million tons of these multilayer films are produced worldwide. When thrown away, those plastics go to landfills, says chemical engineer George Huber of the University of Wisconsin–Madison.
这就是为什么塑料可回收物的第一个目的地是材料回收设施，人员和机器在那里进行分拣。然后，分离出的塑料可以清洗、切碎、熔化和重新成型。该系统适用于苏打水瓶和牛奶罐等简单物品。但不适用于除臭剂 [¹⁸] 容器之类的物品 ——瓶子、曲柄和瓶盖都可以由不同种类的塑料制成。包含几层不同塑料的食品包装薄膜特别难以拆卸 。每年，全球生产 1 亿吨这种多层薄膜。这些塑料被扔掉后会被送往垃圾填埋场，威斯康星大学麦迪逊分校的化学工程师乔治·胡伯 （George Huber） 说。

To tackle that problem, Huber and colleagues devised a strategy for dealing with complex mixtures of plastics. The process uses a series of liquid solvents to dissolve individual plastic components off a product. The trick is choosing the right solvents to dissolve only one kind of plastic at a time, Huber says.
为了解决这个问题，Huber 和同事设计了一种处理复杂塑料混合物的策略。该工艺使用一系列液体溶剂将产品上的单个塑料成分溶解 。Huber 说，诀窍是选择合适的溶剂，一次只溶解一种塑料。

The team tested the technique on a packaging film that contained polyethylene and PET, as well as a plastic oxygen barrier made of ethylene vinyl alcohol[¹⁹], or EVOH, that keeps food fresh.
该团队在含有聚乙烯和 PET 的包装薄膜以及由乙烯乙烯醇制成的塑料氧气阻隔层[¹⁹]（EVOH） 上测试了这项技术，以保持食物新鲜。

Stirring the film into a toluene[²⁰] solvent first dissolved the polyethylene layer. Dunking the remaining EVOH-PET film in a solvent called DMSO[²¹] stripped off the EVOH. The researchers then plucked out the remaining PET film and recovered the other two plastics from their separate solvents by mixing in “antisolvent” chemicals. Those chemicals caused the plastic molecules that were dispersed in the liquids to bunch together into solid clumps that could be fished out.
将薄膜搅拌成甲苯 [²⁰] 溶剂，首先溶解聚乙烯层。将剩余的 EVOH-PET 薄膜浸入一种称为 DMSO[²¹] 的溶剂中，去除 EVOH。然后，研究人员取出剩余的 PET 薄膜，并通过混合“反溶剂”化学品从各自的溶剂中回收另外两种塑料。这些化学物质导致分散在液体中的塑料分子聚在一起，形成可以捞出的固体团块 。

This process recovered practically all of the plastic from the original film, the researchers reported last November in Science Advances. When tested on a jumble of polyethylene, PET and EVOH beads, the solvent washes recovered more than 95 percent of each material — hinting that these solvents could be used to strip plastic components off bulkier items than packaging films. So in theory, recovery facilities could use this technique to disassemble multiplastic deodorant containers and other products of various shapes and sizes.
研究人员去年 11 月在 《科学进展》（Science Advances） 上 报告说 ， 这个过程  几乎从原始薄膜中回收了所有塑料 。当对一堆聚乙烯 、PET 和 EVOH 珠子进行测试时，溶剂清洗回收了每种材料 95% 以上的成分——这意味着这些溶剂可用于从 比包装薄膜更笨重的物品上剥离塑料部件。因此，从理论上讲，回收设施可以使用这种技术来拆卸多塑料除臭剂容器和其他各种形状和大小的产品。

Huber and colleagues next plan to look for solvents to dissolve more kinds of plastic, such as the polystyrene [²²]in Styrofoam[²³] . But it will take a lot more work to make this strategy efficient at sorting all the intricate plastic combinations in real-world recyclables.
Huber 及其同事接下来计划寻找溶剂来溶解更多种类的塑料，例如聚苯乙烯泡沫塑料中的聚苯乙烯 [²²][²³] 。但是，要使这种策略有效地对现实世界中的可回收物中的所有复杂塑料组合进行分类，还需要做更多的工作。

False advertising 
虚假广告

Many plastic products are labeled with a number inside a triangle that symbolizes recycling. Yet, only plastics with 1 (polyethylene terephthalate) or 2 (high-density polyethylene) are widely recycled in the United States. The rest typically go to the landfill. 
许多塑料产品在三角形内标有数字，象征着回收。然而，在美国，只有含有 1（聚对苯二甲酸乙二醇酯）或 2（高密度聚乙烯）的塑料被广泛回收。其余的通常被送往垃圾填埋场。

Water and soft drink bottles, salad domes, cookie trays, salad dressing and peanut butter containers
水和软饮料瓶、沙拉圆顶、饼干托盘、沙拉酱和花生酱容器

Cosmetic containers, commercial cling wrap保鲜膜
化妆品容器、商用保鲜膜

Squeeze bottles, cling wrap, trash bags
挤压瓶子、保鲜膜、垃圾袋

CD cases, plastic disposable cups, plastic cutlery, video cases
CD 盒、塑料一次性杯子、塑料餐具、视频盒

Foam polystyrene hot drink cups, food takeaway trays, protective packaging for fragile items
泡沫聚苯乙烯热饮杯、食品外卖托盘、易碎物品的保护性包装

SOURCE: ELLEN MACARTHUR FOUNDATION 2017
来源：艾伦·麦克阿瑟基金会 2017 年

Making plastics mix
制作塑料混合物

There may also be chemical shortcuts that allow multilayer films and other mixtures of plastics to be recycled as they are. Additives called compatibilizers[²⁴] help different melted-down plastics blend, so that unsorted materials can be treated as one. But there is no universal compatibilizer that allows every kind of plastic to be mixed together. And existing compatibilizers are not widely used because they are not very potent — and adding a lot of compatibilizer to a plastic blend gets expensive.
也可能存在化学捷径，允许多层薄膜和其他塑料混合物按原样回收。称为增容剂 [²⁴] 的添加剂有助于不同的熔融塑料混合，因此可以将未分类的材料视为一种材料。但是没有通用的增容剂可以将各种塑料混合在一起。现有的增容剂没有得到广泛使用，因为它们不是很有效 ——而且在塑料混合物中添加大量增容剂会很昂贵。

To boost viability, Coates and colleagues created a highly potent compatibilizer for polyethylene and polypropylene. Together, those two plastics make up more than half of the world’s plastic. The new compatibilizer molecule contains two segments of polyethylene, interspersed with two segments of polypropylene. Those alternating segments latch onto plastic molecules of the same kind in a mixture, bringing polyethylene and polypropylene together. It’s as if polyethylene were made of Legos, and polypropylene were made of Duplos, and the researchers made a special building block with connectors that fit both types of blocks.
为了提高活性，Coates 及其同事创造了一种 用于聚乙烯和聚丙烯的高效增容剂。这两种塑料加起来占世界塑料的一半以上。新的增容剂分子包含两段聚乙烯，其中穿插着两段聚丙烯。这些交替的片段锁定在混合物中同类塑料分子上，将聚乙烯和聚丙烯结合在一起。就好像聚乙烯是由乐高积木制成的 ，聚丙烯是由 Duplos 制成的 ，研究人员制作了一个特殊的积木，其连接器适合这两种类型的积木。

Having two polyethylene and two polypropylene connectors for each compatibilizer molecule, rather than one, made this compatibilizer stronger than previous versions, Coates and colleagues reported in 2017 in Science. The first test of the new compatibilizer involved welding together strips of polyethylene and polypropylene. Ordinarily, the two materials easily peel apart. But with a layer of compatibilizer between them, the plastic strips broke, rather than the compatibilizer seal, when pulled apart.
Coates 及其同事在 2017 年发表在《科学》杂志上 报告说， 每个增容剂分子有两个聚乙烯和两个聚丙烯连接器，而不是一个，  这使得这种增容剂比以前的版本更强大 。新型增容剂的第一次测试是将 聚乙烯和聚丙烯条焊接在一起。通常，这两种材料很容易剥落。但是，由于它们之间有一层相容剂，当拉开时，塑料条会破裂，而不是相容剂密封件。

In a second test, the researchers mixed the compatibilizer into a melted blend of polyethylene and polypropylene. It took only 1 percent compatibilizer to create a tough new plastic.
在第二次测试中，研究人员将增容剂混合成聚乙烯和聚丙烯的熔融混合物。只需 1% 的增容剂即可制造出一种坚韧的新型塑料。

“These are crazy potent additives,” Coates says. Other compatibilizers had to be added at concentrations up to 10 percent to hold these two plastics together. The new compatibilizer is now the basis for Coates’ start-up, Intermix Performance Materials, based in Ithaca, N.Y.
“这些是疯狂的强效添加剂，”Coates 说。必须以高达 10% 的浓度添加其他增容剂，才能将这两种塑料固定在一起。新的增容剂现在是高茨位于纽约州伊萨卡的初创公司 Intermix Performance Materials 的基础。

Good as new
完好如新

Even if every piece of plastic trash could easily be recycled, that still wouldn’t solve the world’s plastic problem. There are a couple major issues with how recycling currently works that severely limit the usability of recycled materials.
即使每块塑料垃圾都可以轻松回收，那仍然无法解决世界的塑料问题。目前回收的运作方式存在几个主要问题，严重限制了回收材料的可用性。

For one thing, recycled plastics inherit all the dyes, flame retardants and other additives that gave each original plastic piece its distinctive look and feel. “The plastic that you actually recover at the end of all this is really a very complex mixture,” says chemist Susannah Scott of the University of California, Santa Barbara. Few manufacturers can use plastic with a random mishmash [²⁵]of properties to make something new.
首先，回收塑料继承了所有染料、阻燃剂和其他添加剂，这些添加剂赋予了每个原始塑料件独特的外观和感觉。“在这一切结束时，你实际上回收的塑料实际上是一个非常复杂的混合物，”加州大学圣巴巴拉分校的化学家苏珊娜·斯科特说。很少有制造商可以使用具有随机混合 [²⁵] 特性的塑料来制造新的东西。

Plus, recycling breaks some of the chemical bonds in plastic molecules, affecting the strength and consistency of the material. Melting down and remolding plastic is sort of like reheating pizza in the microwave — you get out basically what you put in, just not as good. That limits the number of times plastic can be recycled before it has to be landfilled.
此外，回收会破坏塑料分子中的一些化学键，从而影响材料的强度和一致性。 熔化和重塑塑料有点像在微波炉中重新加热披萨——你基本上得到的是你放入的东西，只是没有那么好。 这限制了塑料在必须被填埋之前可以回收的次数。

The solution to both problems could lie in a new kind of recycling process, called chemical recycling, which promises to make pure new plastic an infinite number of times. Chemical recycling involves taking plastics apart on the molecular level.
这两个问题的解决方案可能在于一种称为化学回收的新型回收工艺，它有望无限次地制造纯新塑料。化学回收涉及在分子水平上分解塑料。

The molecules that make up plastics are called polymers, which are made of smaller monomers[²⁶]. Using heat and chemicals, it is possible to disassemble polymers into monomers, separate those building blocks from dyes and other contaminants, and piece the monomers back together into good-as-new plastic.
构成塑料的分子称为聚合物，由较小的单体制成 [²⁶]。 利用热量和化学品，可以将聚合物分解成单体，将这些构建单元与染料和其他污染物分离，然后将单体重新组装成完好无损的塑料。

“Chemical recycling has really started to emerge as a force, I would say, within the last three or four years,” says University of Pittsburgh’s Beckman. But most chemical recycling techniques are too expensive or energy intensive for commercial use. “It’s not ready for prime time,” he says.
“我想说，在过去的三四年里，化学回收确实开始成为一股力量，”匹兹堡大学的 Beckman 说。但大多数化学回收技术对于商业用途来说过于昂贵或能源密集。“它还没有准备好迎接黄金时段 ，”他说。

Different plastics require different chemical recycling processes, and some break down more easily than others. “The one that’s farthest along is PET,” Beckman says. “That polymer happens to be easy to take apart.” Several companies are developing methods to chemically recycle PET, including the French company Carbios.
不同的塑料需要不同的化学回收工艺，有些塑料比其他塑料更容易分解。“走得最远的是 PET，”贝克曼说。“那种聚合物恰好很容易拆开。”几家公司正在开发化学回收 PET 的方法，包括法国公司 Carbios。

Carbios is testing enzymes produced by microorganisms to break down PET. Researchers at the company described their work on one such enzyme last April in Nature. Microbes normally use the enzyme, called leaf-branch compost[²⁷] cutinase[²⁸], to decompose the waxy coating on plant leaves. But the cutinase is also good at breaking PET down into its monomers: ethylene glycol[²⁹] and terephthalic acid[³⁰] .
Carbios 正在测试微生物产生的酶以分解 PET。该公司 的研究人员去年 4 月在 《自然》 杂志上 描述了他们对一种此类酶的研究 。微生物通常使用一种称为叶枝堆肥 [²⁷] 角质酶 [²⁸] 的酶来分解植物叶子上的蜡质涂层。但角质酶也擅长将 PET 分解成单体： 乙二醇 [²⁹] 和对苯二甲酸 [³⁰]。

Microbial help 
微生物帮助

An enzyme naturally produced by microbes broke down about 50 percent of polyethylene terephthalate, or PET (blue line). A tweaked version of the enzyme broke down more than 80 percent of the plastic (black dotted line). Increasing the amount of the enzyme from 1 milligram per gram of PET to 3 milligrams made it even more efficient — breaking down about 90 percent of PET. 
微生物自然产生的一种酶分解了大约 50% 的聚对苯二甲酸乙二醇酯或 PET（蓝线）。这种酶的调整版本分解了 80% 以上的塑料（黑色虚线）。将酶的量从每克 PET 1 毫克增加到 3 毫克，使其效率更高——分解约 90% 的 PET。

PET breakdown by an enzyme
酶对 PET 的分解

SOURCE: V. TOURNIER ET AL/NATURE 2020
资料来源：V. TOURNIER ET ALNATURE 2020

“The enzyme is like a molecular scissor,” says Alain Marty, chief scientific officer at Carbios. But because it evolved to decompose plant matter, not plastic, it’s not perfect. To make the enzyme better at snipping apart PET, “we redesigned what we call the active site of the enzyme,” Marty says. This involved swapping out some of the amino acids[³¹]along that PET docking site for others.
“这种酶就像一把分子剪刀，”Carbios 首席科学官 Alain Marty 说。但是，因为它进化来分解植物物质，而不是塑料，所以它并不完美。为了使酶更好地剪断 PET，“我们重新设计了我们所谓的酶活性位点，”Marty 说。这涉及将 PET 对接位点的一些氨基酸 [³¹] 换成其他氨基酸。

When the researchers tested their mutant enzyme on colored plastic flakes from PET bottles, applying 3 milligrams of the enzyme per gram of PET, about 90 percent of the plastic broke down in about 10 hours. The original enzyme had maxed out at about 50 percent. Using the terephthalic acid monomers produced in that process, the researchers made new plastic bottles that were just as strong as the originals.
当研究人员在 PET 瓶的彩色塑料片上测试他们的突变酶时，每克 PET 涂抹 3 毫克酶，大约 90% 的塑料在大约 10 小时内分解。原来的酶最高达到了 50% 左右。使用该工艺中产生的对苯二甲酸单体，研究人员制造了与原件一样坚固的新塑料瓶。

Carbios is now building a plant near Lyon, France, to start chemically recycling PET later this year.
Carbios 目前正在法国里昂附近建造一家工厂，将于今年晚些时候开始对 PET 进行化学回收。

Milder conditions
较温和的条件

But other plastics, like polyethylene and polypropylene, are much harder to break down via chemical recycling. Taking apart polyethylene molecules, for instance, requires temperatures over 400° Celsius. At such high heat, the chemistry is chaotic. Plastic molecules break down randomly, generating a complex mixture of compounds that can be burned as fuel but not used to make new materials.
但其他塑料，如聚乙烯和聚丙烯，更难通过化学回收分解。 例如，拆解聚乙烯分子需要超过 400 摄氏度的温度。在如此高的温度下，化学成分是混乱的。塑料分子随机分解，产生复杂的化合物混合物，这些化合物可以作为燃料燃烧，但不能用于制造新材料。

Scott, the UC Santa Barbara chemist, proposes partially breaking down these sturdy plastics in a more controlled way, under milder conditions, to make other kinds of useful molecules. She and colleagues recently came up with a way to transform polyethylene into alkylaromatic[³²]compounds, which can be used as biodegradable ingredients in shampoos, detergents and other products. The process involves placing polyethylene inside a reaction chamber set to 280° C, with a catalyst powder containing platinum nanoparticles[³³].
加州大学圣巴巴拉分校的化学家斯科特提议，在更温和的条件下，以更可控的方式部分分解这些坚固的塑料，以制造其他种类的有用分子。她和同事最近想出了一种将聚乙烯转化为烷基芳烃 [³²] 化合物的方法，这种化合物可以用作洗发水、洗涤剂和其他产品的可生物降解成分。该工艺包括将聚乙烯放入设置为 280°C 的反应室中，并使用含有铂纳米颗粒的催化剂粉末 [³³]。

.

Polyethylene is a long molecule, in which hydrogen atoms are connected to a carbon backbone that can be thousands of carbon atoms long. The platinum is good at breaking carbon-hydrogen bonds, Scott says. “When you do that, you generate hydrogen in the reactor, and the platinum catalyst can use the hydrogen to break the carbon-carbon bonds [in the molecule backbone]. So it actually chops the chain into smaller pieces.”
聚乙烯是一种长分子，其中氢原子连接到可以有数千个碳原子长的碳主链。Scott 说，铂擅长破坏碳氢键。“当你这样做时，你会在反应器中产生氢气，铂催化剂可以使用氢气来破坏 [分子骨架] 中的碳-碳键。所以它实际上是将链条切成更小的块。

Since this reaction takes place at a relatively mild 280° C, it happens in an orderly fashion, snapping long polyethylene molecules into shorter chains that are each about 30 carbons long. Those fragments then arrange themselves into the six-sided ring structures characteristic of alkylaromatic compounds.
由于该反应在相对温和的 280°C 下发生，因此它以有序的方式发生， 将长聚乙烯分子折断成较短的链，每条链长约 30 个碳原子。然后，这些片段排列成烷基芳香族化合物特有的六边环结构。

After 24 hours in the reaction chamber, “most of the products are liquids, and most of the liquids are alkylaromatics,” Scott says. In experiments, about 69 percent of the plastic in a low-density polyethylene bag was converted into liquid. About 55 percent of a high-density polyethylene bottle cap was transformed. The process produces hydrocarbon gases too, which could be used to generate heat to run the reaction at a recycling plant, Scott says.
在反应室中放置 24 小时后，“大多数产物是液体，大多数液体是烷基芳烃，”Scott 说。在实验中，低密度聚乙烯袋 中约 69% 的塑料转化为液体 。大约 55% 的高密度聚乙烯瓶盖被改造。Scott 说，该过程还会产生碳氢化合物气体，这些气体可用于产生热量，以便在回收厂运行反应。

For now, this is just a lab demo, and like many new recycling strategies, it’s still a long way off from commercialization. And no single upgrade to the recycling pipeline will rid the world of its growing mountains of plastic trash. “We’re going to need a suite of technologies to meet this challenge,” says Daniels, of the REMADE Institute. But each new technology — whether it’s focused on making plastics easier to recycle, or transforming them into more useful materials — could help.
目前，这只是一个实验室演示，与许多新的回收策略一样，它距离商业化还有很长的路要走。再一次对回收管道的升级都无法消除世界上堆积如山的塑料垃圾。“我们需要一套技术来应对这一挑战，”REMADE Institute 的 Daniels 说。但每一项新技术——无论是专注于使塑料更容易回收，还是将其转化为更有用的材料——都可以提供帮助。

Built to last
经久耐用

The plastics produced today were never designed to be used more than once. That’s why recycling plastics — particularly into material that is as good as new — is so difficult. But researchers are going back to the drawing board to ask themselves, “What does the next generation of materials look like? How do you design a material specifically so that it never has to go into a landfill?” says Eric Beckman, a chemical engineer at the University of Pittsburgh. “Chemists are looking at whether you can design a polymer that falls apart on command.”
今天生产的塑料从来没有被设计为可以多次使用。这就是为什么回收塑料（尤其是回收成与新塑料一样好的材料）如此困难的原因。 但研究人员正在重新开始问自己，“下一代材料是什么样子的？如何专门设计一种材料，使其永远不必进入垃圾填埋场？“化学家们正在研究你是否可以设计出一种随命令而分崩离析的聚合物。”

The development of a class of next-gen polymers, called PDKs, for poly(diketoenamine)s[³⁴], was reported in Nature Chemistry in 2019. “PDKs have the ability to break their bonds under relatively mild conditions — certainly with much lower energy intensity than any of the plastics that are currently used today,” says study coauthor Brett Helms, a chemist at the Lawrence Berkeley National Laboratory in California. Simply dunking the plastic in an acid solution with a pH of 1 or 2 is enough to break the bonds between its monomer building blocks.
 2019 年 ， 《 自然化学  》杂志报道了一类用于聚（二酮烯胺）的下一代聚合物的开发，称为 PDK[34]。“PDK 能够在相对温和的条件下打破它们的键——当然，其能量强度比目前使用的任何塑料都要低得多，”该研究的合著者、加利福尼亚州劳伦斯伯克利国家实验室的化学家 Brett Helms 说。只需将塑料浸入 pH 值为 1 或 2 的酸溶液中，就足以破坏其单体结构单元之间的键。

“Materials don’t usually encounter a pH that’s that low, so it’s not like if you put PDKs in vinegar, the polymer is going to start breaking down,” Helms says. But it could make for easy recycling. The PDK monomers can then be used to make pristine new plastic, again and again.
“材料通常不会遇到这么低的 pH 值，所以如果你把 PDK 放在醋里，聚合物不会开始分解，”Helms 说。但它可以很容易地回收利用。然后，PDK 单体可以一次又一次地用于制造原始的新塑料。

Widespread plastics like polyethylene terephthalate, or PET, and polyethylene are so cheap to make that any breakout polymer would have a tough time entering the market, Beckman says. So for now, inherently recyclable plastic is just an academic curiosity. But maybe, decades from now, plastics made to be recyclable from the get-go will help solve the world’s plastic waste problem. — Maria Temming
Beckman 说，聚对苯二甲酸乙二醇酯 （PET） 和聚乙烯等广泛使用的塑料制造成本非常低，以至于任何突破性的聚合物都很难进入市场。因此，就目前而言，本质上可回收的塑料只是一种学术上的好奇心。但也许几十年后，从一开始就可回收的塑料将有助于解决世界塑料垃圾问题。 — 玛丽亚·特明

A version of this article appears in the January 30, 2021 issue of Science News.
本文的一个版本发表在 2021 年 1 月 30 日的《科学新闻》杂志上。