Snails’ teeth beats spider silk as nature’s strongest material (2015)

蜗牛牙齿击败蜘蛛丝，成为自然界最强材料（2015）

Marine snails, commonly called limpets, cling tenaciously to rocks as waves batter them. They can clamp on with a force of 75 pounds per square inch, using their muscular mollusk “foot” and a chemical secretion. But even that feat isn’t as stunning as their ability to grind down rock as they feed, using a tooth-studded tongue called a radula. 海洋蜗牛（通常被称为帽贝）在海浪拍打时能顽强地吸附在岩石上。它们利用肌肉发达的软体动物“足”和化学分泌物，能以每平方英寸75磅的力紧紧吸附。但即便如此，它们在进食时利用一种长满牙齿的舌头（称为齿舌）磨碎岩石的能力，依然令人惊叹。

Now the snails have upped their tough-guy street cred with help from engineers based in the U.K., who discovered that these snails’ teeth are made of the strongest natural material out there. Spider silk, often compared to kevlar, has wowed with its tough yet flexible powers. But when tested, the tooth material was, on average, about five times stronger than most spider silk, reports BBC News. This makes it the strongest natural material on Earth. 如今，在英国工程师的帮助下，这些蜗牛的“硬汉”名声更上一层楼——研究人员发现，这些蜗牛的牙齿是由目前已知最强的天然材料制成的。蜘蛛丝常被拿来与凯夫拉（Kevlar）纤维相提并论，其坚韧而灵活的特性令人惊叹。但据BBC新闻报道，经测试，这种牙齿材料的强度平均比大多数蜘蛛丝高出约五倍。这使其成为地球上最强的天然材料。

Tests in the lab revealed that it can withstand pressure that would turn carbon into diamond. That’s comparable to a single strand of spaghetti holding up about 3,300 one-pound bags of sugar, the study’s lead author, Asa Barber of the University of Portsmouth, told the BBC. For Science, David Shultz reports: Scientists discovered that the teeth are made of a mixture of goethite (an iron-containing crystal) nanofibers encased in a protein matrix. 实验室测试显示，它能承受足以将碳转化为钻石的压力。该研究的主要作者、朴茨茅斯大学的阿萨·巴伯（Asa Barber）告诉BBC，这相当于一根意大利面条支撑着约3300袋一磅重的糖。大卫·舒尔茨（David Shultz）为《科学》杂志报道称：科学家们发现，这些牙齿是由包裹在蛋白质基质中的针铁矿（一种含铁晶体）纳米纤维混合而成的。

In spite of their amazing strength, the teeth don’t quite best the strongest humanmade materials like graphene, but the new material’s upper range puts it far ahead of Kevlar and on par with the highest quality carbon fibers. The researchers published their findings in the Journal of the Royal Society Interface. 尽管强度惊人，但这些牙齿仍无法超越石墨烯等最强的人造材料，不过这种新材料的上限远超凯夫拉纤维，并与最高质量的碳纤维相当。研究人员已将研究结果发表在《英国皇家学会界面杂志》（Journal of the Royal Society Interface）上。

If you’re looking for the strongest overall material on Earth, diamond is a good guess, but again, man-made nano-materials beat it. And there are also two rare, natural materials that can withstand more stress than diamond, reports New Scientist. One of those—wurtzite boron nitrate—has a diamond-like arrangement at the atomic level. But while diamonds are made only of carbon, wurtzite boron nitrate also contains (as its name suggests) boron and nitrogen. The other—lonsdaleite—is all carbon but has a hexagonal structure. (Diamond’s cubic.) Lonsdaleite can be created when graphite-containing meteorites plummet to Earth, and it can withstand 58 percent more stress than diamond. 如果你在寻找地球上整体最强的材料，钻石是一个不错的猜测，但同样，人造纳米材料已经超越了它。据《新科学家》杂志报道，还有两种罕见的天然材料能承受比钻石更大的压力。其中一种是纤锌矿型氮化硼（wurtzite boron nitrate），它在原子层面上具有类似钻石的排列结构。但钻石仅由碳组成，而纤锌矿型氮化硼（顾名思义）还含有硼和氮。另一种是蓝碳石（lonsdaleite），它完全由碳组成，但具有六方晶体结构（钻石是立方晶体结构）。蓝碳石可以在含石墨的陨石坠落地球时形成，其承受压力的能力比钻石高出58%。

Hard and strong-yet-flexible materials offer attractive properties for engineers looking to build the next generation of materials, structures and even machines. Now they’ll be turning to the snails as the latest potential nature consultants on these projects. 对于那些致力于构建下一代材料、结构甚至机器的工程师来说，这种既坚硬又强韧且灵活的材料具有极具吸引力的特性。现在，他们将把目光投向蜗牛，将其视为这些项目中最新的潜在“自然顾问”。

Editor’s Note April 5, 2017: As pointed out by one of our eagle-eyed readers Tom Tonon, the terminology in this story could cause confusion for some readers. There are many different scientific terms used to describe an object’s capacity to resist bending or breaking apart, each of which has subtle differences. In this article, we use the terms toughness and strength to refer to the object’s tensile strength—the capacity of an object to resist pulling apart. This differs from compressive strength, which describes the amount of squeezing an object could withstand. The above discussion of wurtzite boron nitrate refers to not to tensile strength but the hardness of the material, which is its capacity to resist scratching or cutting. 编者注（2017年4月5日）：正如我们敏锐的读者汤姆·托农（Tom Tonon）所指出的，本文中的术语可能会让一些读者感到困惑。有许多不同的科学术语用于描述物体抵抗弯曲或断裂的能力，每种术语都有细微的差别。在本文中，我们使用“韧性”（toughness）和“强度”（strength）来指代物体的抗拉强度——即物体抵抗被拉开的能力。这与“抗压强度”（compressive strength）不同，后者描述的是物体所能承受的挤压程度。上述关于纤锌矿型氮化硼的讨论指的不是抗拉强度，而是材料的硬度，即其抵抗刮擦或切割的能力。