Suspended Carbon Nanotube Quantum Wires with Two Gates

美,日电冰箱CFCs替代技术进展情况
钱祯祺
【期刊名称】《电机电器技术》
【年(卷),期】1994(000)001
【摘要】美、日电冰箱ＣＦＣｓ替代技术进展情况钱祯祺受ＵＮＥＰ的邀请，中国电冰箱制冷剂替代技术考察组，于９３年８月１４—２８日对美国、日本当前的电冰箱ＣＦＣｓ替代技术进行了考察。

这次考察是“中国消耗臭氧层物质逐步淘汰国家方案”实施计划中的重要步骤之一，得到ＵＮ...
【总页数】4页(P9-12)
【作者】钱祯祺
【作者单位】无
【正文语种】中文
【中图分类】TM925.2
【相关文献】
1.家用电冰箱CFCs替代技术最新发展动态 [J], 赵先美
2.CFC替代技术在电冰箱和冷柜维修中的应用 [J], 梁勇
3.电冰箱、冷柜、空调器CFC替代技术研究现状 [J], 王天鸿
4.电冰箱CFCs替代技术应用及发展 [J], 俞钟奇
5.日本电冰箱CFC替代技术 [J], 李颂德
因版权原因，仅展示原文概要，查看原文内容请购买。

湖南大学打破纳米线激光器调谐范围世界纪录
佚名
【期刊名称】《《光机电信息》》
【年(卷),期】2009(026)003
【摘要】近日从湖南大学传来喜讯：该校邹炳锁教授领衔的纳米光子学小组与美国亚利桑那州立大学宁存政教授领衔的纳米光子学小组合作，将半导体激光芯片调谐范围（即发光波长所能调节的范围1扩大。

成功地演示出500nm绿光直至700nm红光，创下纳米线激光器调谐范围的世界记录．与原来调谐范围最长仅几十纳米相比。

发光波长调节范围扩大约10倍。

反映这一成果的论文发表在最近一期国际最权威纳米专业杂志《纳米快报》上。

【总页数】1页(P50)
【正文语种】中文
【中图分类】TN248
【相关文献】
1.我国成功改写纳米线激光器调谐范围的世界纪录 [J], 谌立新
2.我国科研人员改写纳米线激光器调谐范围世界纪录 [J],
3.湖南大学改写纳米线激光器调谐范围世界纪录 [J],
4.国内外专家合作改写纳米线激光器调谐范围世界纪录 [J],
5.中美合作纳米线激光器研究获进展打破半导体激光器调谐范围世界纪录 [J],
因版权原因，仅展示原文概要，查看原文内容请购买。

碳纳米管天梯作文100英文回答：Exploring the Potential of Carbon Nanotube Space Elevators.Carbon nanotubes (CNTs), since their discovery in 1991, have captivated the scientific community with their extraordinary properties. Their exceptional strength, low density, and electrical conductivity make them ideal candidates as the building blocks for a multitude of futuristic technologies, including space elevators.A space elevator is a proposed structure that would connect the surface of the Earth to a geostationary orbit 35,786 kilometers above sea level. As it ascends, the elevator would be supported by a series of carbon nanotubes, forming a continuous cable from the ground to space.The concept of a space elevator has been around forover a century, but it was not until the advent of carbon nanotubes that it became a realistic possibility. CNTs possess the strength and lightness necessary to withstand the immense gravitational forces acting on the cable.One of the primary advantages of a space elevator isits cost-effectiveness. Traditional rocket launches can be prohibitively expensive, costing billions of dollars per launch. A space elevator, on the other hand, would providea much more affordable way to transport cargo and personnel into space.The construction of a space elevator would also have significant environmental benefits. Rockets emit large amounts of greenhouse gases and other pollutants into the atmosphere, contributing to global warming and air pollution. A space elevator would eliminate these emissions, making it an environmentally friendly alternative to rocket launches.While the concept of a space elevator is exciting,there are still many challenges that need to be overcomebefore it can become a reality. One of the major obstaclesis the production of carbon nanotubes on a large scale. Currently, CNT production is expensive and time-consuming, making it difficult to produce the vast amount of material required for a space elevator.Another challenge is the need to develop materials that can withstand the harsh conditions of space. The space elevator cable would be exposed to extreme temperatures, radiation, and micrometeoroids, all of which could damagethe material.Despite these challenges, the potential benefits of a space elevator are so great that research and development efforts are ongoing. With continued progress in materials science and engineering, it is possible that a spaceelevator could become a reality within the next few decades.中文回答：碳纳米管太空电梯。

Carbon nanotubeCarbon nanotubes(CNTs) are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1,[1]significantly larger than for any other material. These cylindrical carbon molecules have unusual properties, which are valuable for nanotechnology, electronics, optics and other fields of materials science and technology. In particular, owing to their extraordinary thermal conductivity and mechanical and electrical properties, carbon nanotubes find applications as additives to various structural materials. For instance, nanotubes form a tiny portion of the material(s) in some (primarily carbon fiber) baseball bats, golf clubs, or car parts.[2]Nanotubes are members of the fullerene structural family. Their name is derived from their long, hollow structure with the walls formed by one-atom-thick sheets of carbon, called graphene. These sheets are rolled at specific and discrete ("chiral") angles, and the combination of the rolling angle and radius decides the nanotube properties; for example, whether the individual nanotube shell is a metal or semiconductor. Nanotubes are categorized as single-walled nanotubes (SWNTs) and multi-walled nanotubes(MWNTs). Individual nanotubes naturally align themselves into "ropes" held together by van der Waals forces, more specifically, pi-stacking.Applied quantum chemistry, specifically, orbital hybridization best describes chemical bonding in nanotubes. The chemical bonding of nanotubes is composed entirely of sp2 bonds, similar to those of graphite. These bonds, which are stronger than the sp3bonds found in alkanes and diamond, provide nanotubes with their unique strength.TerminologyThere is no consensus on some terms describing carbon nanotubes in scientific literature: both "-wall" and "-walled" are being used in combination with "single", "double", "triple" or "multi", and the letter C is often omitted in the abbreviation; for example, multi-walled carbon nanotube (MWNT).Single-walledMost single-walled nanotubes (SWNT) have a diameter of close to 1 nanometer, with a tube length that can be many millions of times longer. The structure of a SWNT can be conceptualized by wrapping a one-atom-thick layer of graphite called graphene into a seamless cylinder. The way the graphene sheet is wrapped is represented by a pair of indices (n,m). The integers n and m denote the number of unit vectors along two directions in the honeycomb crystal lattice of graphene. If m= 0, the nanotubes are called zigzag nanotubes, and if n= m, the nanotubes are called armchair nanotubes. Otherwise, they are called chiral. The diameter of an ideal nanotube can be calculated from its (n,m) indices as followswhere a = 0.246 nm.SWNTs are an important variety of carbon nanotube because most of their properties change significantly with the (n,m) values, and this dependence is non-monotonic (see Kataura plot). In particular, their band gap can vary from zero to about 2 eV and their electrical conductivity can show metallic or semiconducting behavior. Single-walled nanotubes are likely candidates for miniaturizing electronics. The most basic building block of these systems is the electric wire, and SWNTs with diameters of an order of a nanometer can be excellent conductors.[3][4] One useful application of SWNTs is in the development of the first intermolecular field-effect transistors(FET). The first intermolecular logic gate using SWCNT FETs was made in 2001.[5] A logic gate requires both a p-FET and an n-FET. Because SWNTs are p-FETs when exposed to oxygen and n-FETs otherwise, it is possible to protect half of an SWNT from oxygen exposure, while exposing the other half to oxygen. This results in a single SWNT that acts as a NOT logic gate with both p and n-type FETs within the same molecule.Single-walled nanotubes are dropping precipitously in price, from around $1500 per gram as of 2000 to retail prices of around $50 per gram of as-produced 40–60% by weight SWNTs as of March 2010Multi-walledMulti-walled nanotubes (MWNT) consist of multiple rolled layers (concentric tubes) of graphene. There are two models that can be used to describe the structures of multi-walled nanotubes. In the Russian Doll model, sheets of graphite are arranged in concentric cylinders, e.g., a (0,8) single-walled nanotube (SWNT) within a larger (0,17) single-walled nanotube. In the Parchment model, a single sheet of graphite is rolled in around itself, resembling a scroll of parchment or a rolled newspaper. The interlayer distance in multi-walled nanotubes is close to the distance between graphene layers in graphite, approximately 3.4 Å. The Russian Doll structure is observed more commonly. Its individual shells can be described as SWNTs, which can be metallic or semiconducting. Because of statistical probability and restrictions on the relative diameters of the individual tubes, one of the shells, and thus the whole MWNT, is usually a zero-gap metal.Double-walled carbon nanotubes (DWNT) form a special class of nanotubes because their morphology and properties are similar to those of SWNT but their resistance to chemicals is significantly improved. This is especially important when functionalization is required (this means grafting of chemical functions at the surface of the nanotubes) to add new properties to the CNT. In the case of SWNT, covalent functionalization will break some C=C double bonds, leaving "holes" in the structure on the nanotube and, thus, modifying both its mechanical and electrical properties. In the case of DWNT, only the outer wall is modified. DWNT synthesis on the gram-scale was first proposed in 2003[6]by the CCVD technique, from the selective reduction of oxide solutions in methane and hydrogen.The telescopic motion ability of inner shells[7] and their unique mechanical properties[8] permit to use multi-walled nanotubes as main movable arms in comingnanomechanical devices. Retraction force that occurs to telescopic motion caused by the Lennard-Jones interaction between shells and its value is about 1.5 nN.[9]TorusIn theory, a nanotorus is a carbon nanotube bent into a torus (doughnut shape). Nanotori are predicted to have many unique properties, such as magnetic moments 1000 times larger than previously expected for certain specific radii.[10]Properties such as magnetic moment, thermal stability, etc. vary widely depending on radius of the torus and radius of the tube.NanobudCarbon nanobuds are a newly created material combining two previously discovered allotropes of carbon: carbon nanotubes and fullerenes. In this new material, fullerene-like "buds" are covalently bonded to the outer sidewalls of the underlying carbon nanotube. This hybrid material has useful properties of both fullerenes and carbon nanotubes. In particular, they have been found to be exceptionally good field emitters. In composite materials, the attached fullerene molecules may function as molecular anchors preventing slipping of the nanotubes, thus improving the composite’s mechanic al properties.Graphenated carbon nanotubesGraphenated CNTs are a relatively new hybrid that combines graphitic foliates grown along the sidewalls of multiwalled or bamboo style CNTs. Yu et al.[12] reported on "chemically bonded graphene leaves" growing along the sidewalls of CNTs. Stoner et al.[13] described these structures as "graphenated CNTs" and reported in their use for enhanced supercapacitor performance. Hsu et al. further reported on similar structures formed on carbon fiber paper, also for use in supercapacitor applications.[14]The foliate density can vary as a function of deposition conditions (e.g. temperature and time) with their structure ranging from few layers of graphene (< 10) to thicker, more graphite-like.[15]The fundamental advantage of an integrated graphene-CNT structure is the high surface area three-dimensional framework of the CNTs coupled with the high edge density of graphene. Graphene edges provide significantly higher charge density and reactivity than the basal plane, but they are difficult to arrange in a three-dimensional, high volume-density geometry. CNTs are readily aligned in a high density geometry (i.e., a vertically aligned forest)[16] but lack high charge density surfaces—the sidewalls of the CNTs are similar to the basal plane of graphene and exhibit low charge density except where edge defects exist. Depositing a high density of graphene foliates along the length of aligned CNTs can significantly increase the total charge capacity per unit of nominal area as compared to other carbon nanostructures.[Nitrogen Doped Carbon NanotubesNitrogen doped carbon nanotubes (N-CNT's), can be produced through 5 main methods, Chemical Vapor Deposition,[18][19]high-temperature and high pressure reactions,gas-solid reaction of amorphous carbon with NHat high temeprature,[20]solid3reaction,[21] and solvothermal synthesis.[22]N-CNTs can also be prepared by a CVD method of pyrolysizing melamine under Ar at elevated temperatures of 800o C - 980o C. However synthesis via CVD and melamine results in the formation of bamboo structured CNTs. XPS spectra of grown N-CNT's reveals nitrogen in five main components, pyridinic nitrogen, pyrrolic nitrogen, quaternanry nitrogen, and nitrogen oxides. Furthermore synthesis temperature affects the type of nitrogen configuration.[23]Nitrogen doping plays a pivotal role in Lithium storage. N-doping provides defects in the walls of CNT's allowing for Li ions to diffuse into interwall space. It also increases capacity by providing more favorable bind of N-doped sites. N-CNT's are also much more reactive to metal oxide nanoparticle deposition which can further enhance storage capacity, especially in anode materials for Li-ion batteries. PeapodA Carbon peapod is a novel hybrid carbon material which traps fullerene inside a carbon nanotube. It can possess interesting magnetic properties with heating and irradiating. It can also be applied as an oscillator during theoretical investigations and predictions.Cup-stacked carbon nanotubesCup-stacked carbon nanotubes (CSCNTs) differ from other quasi-1D carbon structures, which normally behave as quasi-metallic conductors of electrons. CSCNTs exhibit semiconducting behaviors due to the stacking microstructure of graphene layers.[Extreme carbon nanotubesThe observation of the longest carbon nanotubes (18.5 cm long) was reported in 2009. These nanotubes were grown on Si substrates using an improved chemical vapor deposition (CVD) method and represent electrically uniform arrays of single-walled carbon nanotubes.[1]The shortest carbon nanotube is the organic compound cycloparaphenylene, which was synthesized in early 2009.[30][31][32]The thinnest carbon nanotube is armchair (2,2) CNT with a diameter of 3 Å. This nanotube was grown inside a multi-walled carbon nanotube. Assigning of carbon nanotube type was done by combination of high-resolution transmission electron microscopy(HRTEM), Raman spectroscopy and density functional theory(DFT) calculations.[33]The thinnest freestanding single-walled carbon nanotube is about 4.3 Å in diameter. Researchers suggested that it can be either (5,1) or (4,2) SWCNT, but exact type of carbon nanotube remains questionable.[34](3,3), (4,3) and (5,1) carbon nanotubes (all about 4 Å in diameter) were unambiguously identified using more precise aberration-corrected high-resolution transmission electron microscopy. However,they were found inside of double-walled carbon nanotubes.[碳纳米管碳纳米管(碳)是同素异形体的碳是圆柱形奈米结构。

碳纳米管对重金属吸附研究的英文文献Research on Heavy Metal Adsorption Using Carbon NanotubesCarbon nanotubes (CNTs) have attracted significant attention for their potential applications in environmental remediation due to their unique properties, such as high surface area, large aspect ratio, and outstanding mechanical and electrical properties. Among various environmental pollutants, heavy metals play an important role due to their toxicity, persistence, and the potential risk to human health and the ecosystem. CNTs have been reported to be effective in removing heavy metals from aqueous solutions.In recent years, researchers have explored the use of CNTs as adsorbents for various heavy metals, including lead, cadmium, chromium, mercury, and arsenic. The adsorption of heavy metals by CNTs is mainly governed by physical and chemical interactions, such as electrostatic attraction, van der Waals forces, and chemisorption. The efficiency of heavy metal removal is influenced by several factors, such as the pH of the solution, the concentration of heavy metals, the surface functionalization of CNTs, and the presence of other ions.The adsorption capacity of CNTs for heavy metals is dependent on their surface properties, such as the presence of functional groups. For example, carboxylic acid groups on CNTs can enhance the adsorption capacity for heavy metals through ion exchange and electrostatic interactions. Inaddition, the modification of CNTs with other materials, such as polymers and nanoparticles, can improve the selectivity and efficiency of heavy metal adsorption.CNTs have been demonstrated to be effective in removing heavy metals from contaminated water and soil. However, further research is needed to optimize their performance and understand the mechanisms of heavy metal adsorption. The use of CNTs for heavy metal remediation holds great promise, and may provide a cost-effective and sustainable solution for environmental cleanup.。

利用静电纺碳纳米纤维网制作锂离子二次电池的正极材料Chan Kim;刘呈坤
【期刊名称】《合成纤维》
【年(卷),期】2008(37)12
【摘要】利用聚合物溶液,通过静电纺以及热处理,制备了碳纳米纤维电极。

这种电极具有较大的可及表面积(纤维尺寸处于纳米级范围)、高碳纯度(无粘结剂)、相对较高的电导率、结构完整性、薄纤维网外观形态、较大的可逆容量(约450mAh.g-)1以及基本呈线性的电压分布。

可以想象,由于锂离子在这种活性材料里显著减小的扩散通道,该种新型碳材料将会成为制作大功率锂离子电池阳极材料(需要较高的电流)的理想候选材料。

【总页数】5页(P43-46)
【关键词】锂离子二次电池;碳纳米纤维;正极材料;纤维网;静电纺;制作;聚合物溶液;结构完整性
【作者】Chan Kim;刘呈坤
【作者单位】西安交大
【正文语种】中文
【中图分类】TQ342.742;TM912
【相关文献】
1.静电纺制备二氧化锡/碳纳米纤维锂离子电池负极材料的研究进展 [J], 周惠敏;李智勇;牛潇;夏鑫
2.静电纺丝法制备尖晶石型LiMn2O4纳米纤维锂离子电池正极材料 [J], 戴剑锋;闫兴山;田西光;李维学;王青
3.电纺自支撑空穴硅碳纳米纤维在高性能锂离子电池阳极材料中的应用 [J], 赵丹;刘书武;彭信文;胡唤;侯豪情
4.静电纺纳米材料在锂离子电池中的应用 [J], 张子浩
5.静电纺纳米纤维锂离子电池隔膜研究进展 [J], 张妍;于宾;翟梦真;王晓涵
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气体扩散层纤维烧结钛
最近，科学家们发现了一种新型的气体扩散层材料——纤维烧结钛。

这种材料具有优异的气体扩散性能和高温稳定性，可广泛应用于太阳能电池、氢燃料电池等领域。

纤维烧结钛的制备过程相对简单，通过高温下的烧结和压缩等工艺，可以将钛粉末烧结成纤维状的材料。

这种材料具有均匀的孔隙分布和高度连通的气体通道，可实现优异的气体扩散性能。

此外，纤维烧结钛还具有良好的高温稳定性，能耐受高达1000℃的温度，并且具有较强的机械强度和韧性。

这些特性使得纤维烧结钛在太阳能电池和氢燃料电池等高温环境下的应用具有广阔的前景。

当前，科学家们正在进一步研究纤维烧结钛的制备工艺和性能优化，希望能够进一步扩大其在能源领域的应用。

- 1 -。

单壁碳纳米管（Single-Walled Carbon Nanotubes，SWCNTs）的扭曲形变可以显著影响其氢吸附性能。

以下是扭曲形变对氢吸附的一些影响：
表面积增加：扭曲形变可以导致SWCNTs的表面积增加，从而提供更多的吸附位点，增加氢气吸附的机会。

扭曲应力：扭曲形变引入了SWCNTs内部的应力，这可能会影响氢分子在纳米管表面的吸附和解离过程。

扭曲应力可能会改变氢分子与纳米管之间的相互作用，从而影响吸附能力。

孔径变化：扭曲形变可能导致SWCNTs的孔径发生变化。

由于氢分子的尺寸较小，孔径的变化可能会影响氢分子的进入和离开纳米管的能力。

极性变化：扭曲形变可以引起SWCNTs表面的极性变化。

由于氢分子是非极性分子，SWCNTs 表面的极性变化可能会影响氢分子与纳米管之间的相互作用，从而影响氢吸附能力。

碳纳米管天梯作文200字英文回答：Carbon nanotubes (CNTs) are a fascinating and innovative material with a wide range of applications. These cylindrical structures, composed of carbon atoms, have a unique set of properties that make them highly desirable in various fields.One of the most notable characteristics of CNTs istheir exceptional strength. They are about 100 times stronger than steel, yet much lighter. This makes themideal for applications where strength and lightweight are crucial, such as in aerospace engineering. For example, CNTs can be used to develop lighter and more fuel-efficient aircraft, reducing both cost and environmental impact.In addition to their strength, CNTs also possess excellent electrical conductivity. This property makes them valuable in electronics and electrical engineering. Forinstance, CNTs can be used to create faster and more efficient computer processors, leading to improved performance in various electronic devices. Furthermore, their electrical conductivity also makes them suitable for energy storage applications, such as in batteries and supercapacitors.Moreover, CNTs have a high aspect ratio, meaning their length is much greater than their diameter. This unique shape allows them to act as excellent reinforcements in composite materials. By incorporating CNTs into composites, the overall strength and stiffness of the material can be significantly enhanced. This has implications in the automotive industry, where lightweight and strong materials are essential for improving fuel efficiency and safety.Furthermore, CNTs have shown promise in the field of medicine. Their small size and high surface area-to-volume ratio make them ideal for drug delivery systems. CNTs can be functionalized with specific molecules to targetspecific cells or tissues, allowing for more precise and effective drug delivery. This has the potential torevolutionize the way we treat diseases and improve patient outcomes.Overall, carbon nanotubes are a remarkable material with a wide range of applications. Their exceptional strength, electrical conductivity, shape, and potential in medicine make them highly sought after in various industries.中文回答：碳纳米管（CNTs）是一种迷人且创新的材料，具有广泛的应用领域。