纳米的英文短文

纳米是长度单位，原称毫微米，就是10^-9米（10亿分之一米）。纳米nanotechnology

Based on the metrology legal norm, the basic concept of nanometer measurement is introduced firstly in this paper. It includes nanometer, measurement, nanometer standard, nanometer measurement instrument, nanometer measurement method, nanometer length, etc. Then, the present status of the measurement of nanometer length is described. More attention is paid to the development and the prospect of the microscope technology for measuring nanometer length

Nanotechnology is a highly multidisciplinary field, drawing from fields such as applied physics, materials science, interface and colloid science, device physics, supramolecular chemistry (which refers to the area of chemistry that focuses on the noncovalent bonding interactions of molecules), self-replicating machines and robotics, chemical engineering, mechanical engineering, biological engineering, and electrical engineering. Much speculation exists as to what may result from these lines of research. Nanotechnology can be seen as an extension of existing sciences into the nanoscale, or as a recasting of existing sciences using a newer, more modern term. Grouping of the sciences under the umbrella of "nanotechnology" has been questioned on the basis that there is little actual boundary-crossing between the different sciences that operate on the nano-scale. Instrumentation is the only area of technology common to all disciplines; on the contrary, for example pharmaceutical and semiconductor industries do not "talk with each other". Corporations that call their products "nanotechnology" typically market them only to a certain industrial cluster.Two main approaches are used in nanotechnology. In the "bottom-up" approach, materials and devices are built from molecular components which assemble themselves chemically by principles of molecular recognition. In the "top-down" approach, nano-objects are constructed from larger entities without atomic-level control. The impetus for nanotechnology comes from a renewed interest in Interface and Colloid Science, coupled with a new generation of analytical tools such as the atomic force microscope (AFM), and the scanning tunneling microscope (STM). Combined with refined processes such as electron beam lithography and molecular beam epitaxy, these instruments allow the deliberate manipulation of nanostructures, and lead to the observation of novel phenomena.Examples of nanotechnology in modern use are the manufacture of polymers based on molecular structure, and the design of computer chip layouts based on surface science. Despite the great promise of numerous nanotechnologies such as quantum dots and nanotubes, real commercial applications have mainly used the advantages of colloidal nanoparticles in bulk form, such as suntan lotion, cosmetics, protective coatings, drug delivery, and stain resistant clothing.

From size, it usually generate significant changes in chemical and physical properties of small particle size in 0.1 microns (note 1 m = 100 centimeters, 1 centimeter = 10,000 microns, 1 micron = 10 nanometers, 1 nano = 10 ella), namely below 100 nanometers. Therefore, particle size in 1 ~ 100 nanometer particles called ultra fime grain materials, is also a kind of nanometer materials. Nano metal material is the middle of 1980s, then the successful development of field contains nano semiconducting film, nano ceramic, nano CiXing materials and nano biomedical materials. Nanoscale structure material referred to as the nanometer material (nano material), is to show its structure unit size between 1 nano ~ 100 nanometer range between. Because of its size is close to electronic coherence length, and its nature because strong coherent brings the self-organization makes properties change greatly. And, its scale has come close to the wavelength of light, plus its surface with large special effect, thus its display properties, such as melting point, magnetic, optical, heat conductivity, conductive properties etc, often is different from the substance in overall state behavior of nature. Nanoparticles material called utrasmall particle materials from the nanoparticles (nano distinguish) composition. Nanoparticles also called utrasmall particle size, generally means within 1 ~ 100nm between particles, is in atom clusters and macro objects at the junction of the transition region, from the macro and micro usually on the viewpoint, this system not only atypical microscopic system also atypical macroscopic systems, is a kind of typical mesoscopic system, has the surface effect, small size effect and the macroscopic quantum tunneling effect. When people put the macro object subdivided into utrasmall particle (nanometer level), it will display a lot of exotic characteristics, namely its optical, heat, electricity, magnetic, mechanical and chemical properties of solid and bulky than when there will be significant different.Nanotechnology generalized range including nano materials technology and nano machining technology, nano measurement technology, nano application technology, etc. One nanometer material technology focuses on nano functional material production (superfine powder, coating, nano modified materials etc), performance testing technology (chemical composition, microstructure and surface morphology and geophysical, geochemical and electric, magnetic and optical properties, such as heat and). Nano machining technology contains precision machining technology (energy beam machining, etc) and scanning probe techniques. Nanomaterials has certain uniqueness, when matter scale small to certain degree, then have to switch to quantum mechanics to replace traditional mechanical view to describe its behavior, when powder particles size by 10 micron drop to 10 nano, its size is changed for 1,000 times, but converted volume is ten nine 4k times the giant, so both behavior will generate obvious difference. Nanoparticles are different from large physical reason is in the surface area of the relative increase, namely utrasmall particle surface was full of ladder shape structure, the structure with high surface can represent the unrest atoms. This kind of atomic extremely easily with foreign atomic adsorption of bonding, at the same time because narrow particle size and provides large surface activity of atoms. It is melting point, nano powder due to each particle constituent atoms less, surface atomic in instability, make its surface lattice vibration amplitude of the bigger, so has the high surface energy, causing utrasmall particle unique thermal property, also is caused by melting down, as nano powder will than traditional powder easy in low temperature sintering and become good sintering promote materials从尺寸大小来说，通常产生物理化学性质显著变化的细小微粒的尺寸在0.1微米以下（注1米＝100厘米，1厘米＝10000微米，1微米＝1000纳米，1纳米＝10埃），即100纳米以下。因此，颗粒尺寸在1～100纳米的微粒称为超微粒材料，也是一种纳米材料。 纳米金属材料是20世纪80年代中期研制成功的，后来相继问世的有纳米半导体薄膜、纳米陶瓷、纳米瓷性材料和纳米生物医学材料等。 纳米级结构材料简称为纳米材料(nano material)，是指其结构单元的尺寸介于1纳米～100纳米范围之间。由于它的尺寸已经接近电子的相干长度，它的性质因为强相干所带来的自组织使得性质发生很大变化。并且，其尺度已接近光的波长，加上其具有大表面的特殊效应，因此其所表现的特性，例如熔点、磁性、光学、导热、导电特性等等，往往不同于该物质在整体状态时所表现的性质。 纳米颗粒材料又称为超微颗粒材料，由纳米粒子(nano particle)组成。纳米粒子也叫超微颗粒，一般是指尺寸在1～100nm间的粒子，是处在原子簇和宏观物体交界的过渡区域，从通常的关于微观和宏观的观点看，这样的系统既非典型的微观系统亦非典型的宏观系统，是一种典型的介观系统，它具有表面效应、小尺寸效应和宏观量子隧道效应。当人们将宏观物体细分成超微颗粒（纳米级）后，它将显示出许多奇异的特性，即它的光学、热学、电学、磁学、力学以及化学方面的性质和大块固体时相比将会有显著的不同。 纳米技术的广义范围可包括纳米材料技术及纳米加工技术、纳米测量技术、纳米应用技术等方面。其中纳米材料技术着重于纳米功能性材料的生产（超微粉、镀膜、纳米改性材料等），性能检测技术（化学组成、微结构、表面形态、物、化、电、磁、热及光学等性能）。纳米加工技术包含精密加工技术（能量束加工等）及扫描探针技术。 纳米材料具有一定的独特性，当物质尺度小到一定程度时，则必须改用量子力学取代传统力学的观点来描述它的行为，当粉末粒子尺寸由10微米降至10纳米时，其粒径虽改变为1000倍，但换算成体积时则将有10的9次方倍之巨，所以二者行为上将产生明显的差异。 纳米粒子异于大块物质的理由是在其表面积相对增大，也就是超微粒子的表面布满了阶梯状结构，此结构代表具有高表面能的不安定原子。这类原子极易与外来原子吸附键结，同时因粒径缩小而提供了大表面的活性原子。 就熔点来说，纳米粉末中由于每一粒子组成原子少，表面原子处于不安定状态，使其表面晶格震动的振幅较大，所以具有较高的表面能量，造成超微粒子特有的热性质，也就是造成熔点下降，同时纳米粉末将比传统粉末容易在较低温度烧结，而成为良好的烧结促进材料。 一般常见的磁性物质均属多磁区之集合体，当粒子尺寸小至无法区分出其磁区时，即形成单磁区之磁性物质。因此磁性材料制作成超微粒子或薄膜时，将成为优异的磁性材料。 纳米粒子的粒径（10纳米～100纳米）小于光波的长，因此将与入射光产生复杂的交互作用。金属在适当的蒸发沉积条件下，可得到易吸收光的黑色金属超微粒子，称为金属黑，这与金属在真空镀膜形成高反射率光泽面成强烈对比。纳米材料因其光吸收率大的特色，可应用于红外线感测器材料。 纳米技术在世界各国尚处于萌芽阶段，美、日、德等少数国家，虽然已经初具基础，但是尚在研究之中，新理论和技术的出现仍然方兴未艾。我国已努力赶上先进国家水平，研究队伍也在日渐壮大。