站内查询
您现在的位置是:主页 > 澳门威尼斯人手机app下载 > 二维冰存在及生长机制首获证实
二维冰存在及生长机制首获证实
2020-01-08 01:38  www.affilinker.com

???????近百年来,人类发现了冰的18种三维结构,其中最常见的就是六角形的冰相,例如飘落的雪花、解暑的冰块、南极的厚冰层。但自然界是否有稳定存在的二维冰,一直缺乏确切的实验证据。北京大学、美国内布拉斯加大学林肯分校以及中国科学院的研究团队,利用高分辨qPlus型原子力显微镜技术,首次在实验上证实了二维冰的存在,并以原子级分辨率拍到了二维冰的形成过程,揭示了其特殊的生长机制。该成果2日发表于国际顶级学术期刊《自然》。

? ?? ?? ?? In the last century, humans have discovered 18 three-dimensional structures of ice, the most common of which are hexagonal ice phases, such as falling snowflakes, summer ice, and thick Antarctic ice. But whether there is a stable existence of two-dimensional ice in nature has been lack of exact experimental evidence. Using high-resolution qplus atomic force microscopy, the team from peking university, university of nebraska lincoln and the chinese academy of sciences confirmed the existence of two-dimensional ice for the first time, and captured the formation of two-dimensional ice at atomic-level resolution, revealing its special growth mechanism. The results were published in the world's top academic journal Nature on the 2nd.

???????在此次研究中,科研人员精确控制温度和水压,在疏水的金衬底上,首次生长出这种单晶二维冰结构。他们将非侵扰式原子力显微镜成像技术运用于二维冰的亚分子级分辨成像,再结合理论计算确定了其原子结构。

? ?? ?? ?? In this study, researchers precisely controlled the temperature and water pressure, on the hydrophobic gold substrate, the first growth of this single crystal two-dimensional ice structure. They applied non-intrusive atomic force microscopy to submolecular-level resolution imaging of two-dimensional ice and combined with theoretical calculations to determine its atomic structure.

???????“结果表明,二维冰由两层六角冰无旋转堆叠而成,两层之间靠氢键连接,每个水分子与同一层的水分子形成三个氢键,与上下层的水分子形成一个氢键,因此所有的氢键都被饱和,结构非常稳定,是一种可以独立存在的‘自饱和’二维冰。”文章通讯作者之一、北京大学量子材料科学中心教授江颖说,这也是第一种被实验证实的二维冰结构,研究人员将它命名为“二维冰I相”。

? ?? ?? ?? "The results show that the two-dimensional ice is composed of two layers of hexagonal ice without rotating stacking, and the two layers are connected by hydrogen bonds. Each water molecule forms three hydrogen bonds with the water molecule of the same layer and one hydrogen bond with the water molecule of the upper and lower layers. Jiang Ying, a co-author of the article and a professor at the Center for Quantum Materials Science at Peking University, said it was also the first experimentally confirmed two-dimensional ice structure, which researchers named "two-dimensional ice phase I."

???????怎样才能看到二维冰的形成?研究人员将二维冰从零下153摄氏度“速冻”到零下268摄氏度,把冰生长过程中的一系列中间状态冻结下来,并对其进行稳定的成像,提出了二维冰岛锯齿状边界的“搭桥”式生长和扶椅状边界的“播种”式生长机制。

? ?? ?? ?? How can we see the formation of two-dimensional ice? Researchers frozen two-dimensional ice from minus 153 degrees celsius to minus 268 degrees celsius, frozen a series of intermediate states during ice growth, and made a stable imaging of it, proposing a "bridging" growth mechanism for the zigzag boundary of two-dimensional iceland and a "sowing" growth mechanism for the armchair boundary.

???????二维冰的发现不仅挑战了100多年来人们对冰相的传统认识,而且应用前景广阔。“如果有二维冰存在,三维冰会贴着表面生长,非常稳固。但如果没有二维冰,形成的三维冰与表面接触面很小,很容易被风吹走。我们可以根据二维冰的结构更有针对性地设计和研发防结冰材料。”江颖认为,利用二维冰,可以减小材料之间的摩擦。此外,二维冰可以作为一种特殊的二维材料,为高温超导电性、深紫外探测、冷冻电镜成像等研究提供全新平台。(金凤)

? ?? ?? ?? The discovery of two-dimensional ice not only challenges the traditional understanding of ice phase for more than 100 years, but also has a broad application prospect. "If two-dimensional ice exists, three-dimensional ice will grow very firmly against the surface. But if there is no two-dimensional ice, the formed three-dimensional ice and the surface contact surface is very small, it is easy to be blown away by the wind. We can design and develop anti-icing materials based on the structure of two-dimensional ice. Jiang Ying believes that using two-dimensional ice can reduce the friction between materials. In addition, two-dimensional ice can be used as a special two-dimensional material to provide a new platform for the study of high-temperature superconductivity, deep ultraviolet detection, freezing electron microscopy imaging and so on. (Golden Phoenix)