基于等离激元的全光逻辑和半加器研究取得新进展

中科院物理所/北京凝聚态物理国家实验室（筹）徐红星研究组将几条银纳米线组装在一起形成具有输入端和输出端的简单网络结构,通过控制输入光的偏振和相位,可以在微观尺度上控制等离激元的传播方向,从而可以控制输出端的光强。     

科研进展

我国重离子径迹中金纳米线研究获重要进展近代物理所刘杰研究员主持的“西部之光”项目“重离子径迹中纳米微针的形成和制备”取得重要进展,金纳米线阵列的相关研究成果发表在《纳米技术》(N anotechnology)上。由于金纳米线拥有良好的电、热、机械等特性,在纳米电子学领域具有     

中空管状氧化锌纳米线阵列的制备

基于水热法在三维柔性碳布表面集成了有序ZnO纳米线阵列,之后将集成结构置于石英管式炉中,空气气氛中退火。高温条件下,碳布与空气中的氧发生反应生成气态二氧化碳挥发出去,剩下中空的管状ZnO纳米线阵列。碳布可置换成其他形式的碳基底,如碳毡、碳颗粒、平面石墨等,从而得到空心管状、空心球状、平面状的ZnO纳米线阵列。该方法为大批量制备有序ZnO纳米线提供了新的思路,在光伏、压电、传感等应用ZnO纳米线的领域具有深远意义。     

科研进展

基于等离激元的全光逻辑和半加器研究取得新进展中科院物理所/北京凝聚态物理国家实验室(筹)徐红星研究组将几条银纳米线组装在一起形成具有输入端和输出端的简单网络结构,通过控制输入光的偏振和相位,可以在微观尺度上控制等离激元的传播方向,     

大学物理教学中对光偏振现象的量子论解释

对大学物理课程中没有涉及的部分--用量子力学理论解释光偏振现象进行了讨论.运用量子态叠加的基本原理和方法,以尽量不超出大二学生知识范围的方式分析光偏振状态和光子自旋角动量的对应关系,并简单介绍了光偏振在工程技术领域的多种应用.     

基于等离激元的逻辑运算的可扩展性研究取得新进展

中科院物理所／北京凝聚态物理国家实验室（筹）徐红星研究组在金属纳米线的等离激元性质研究方面做出了一系列的工作,包括远程激发的拉曼散射、与激子的相互作用、发射方向、发射偏振、分光特性、衬底效应、在弯曲纳米线中的传播等。     

磁性镍纳米线的生长演化

利用交流电沉积在有序多孔氧化铝膜内制备了镍磁性纳米线。采用EFSEM、TEM等方法对镍纳米线阵列进行表征,并用VSM对样品的磁性能进行测试。结果显示,镍纳米线在生长过程中发生晶体演化现象,出现多晶→单晶→多晶→单晶的生长模式。     

宽带分路器中双折射现像引起偏振相关损耗(PDL)变化的研究

本文分析了宽带分路器中双折射现像对偏振相关损耗(PDL Polarizationdependentloss)的影响,结果发现:1)分路器的直通臂和耦合臂的偏振相关损耗相同;2)随制备分路器的拉伸速度的增大,1310nm波长的偏振相关损耗与1550nm波长的偏振相关损耗的变化曲线有一交叉点;3) 在小于交叉点的范围内,由于双折射效应,使1310nm光的偏振相关损耗小于1550nm光的偏振相关损耗.4)在大于交叉点范围内,由于分路器内的拉伸应力做用,1310nm光的偏振相关损耗明显增大,1550nm光的偏振相关损耗平稳减小;5)发现在交叉点处偏振相关损耗最小,我们从大量的实验数据得出制备50%分光单模双窗分路器的最佳熔融拉伸速度为0.25±0.05mm/s.     

SiO_xN_y纳米线在碳微结构上的集成特性研究

基于光刻、热解工艺制备了碳微结构阵列,在光刻胶碳化的过程中,利用化学气相沉积法在碳微结构表面一体集成了SiO_xN_y纳米线结构。通过对工艺过程分析,探究了SiO_xN_y纳米线在碳微结构表面的选择性生长现象,揭示了热解和纳米线生长一体化的微纳集成原理,实现了纳米线在三维碳微结构上的定域、有效集成。对该结构进行接触角实验,发现其具有良好的疏水性能。     

讨论光入射界面时反射光和入射光的偏振态

本文对菲涅耳公式进行了推导,并深入地研究了光入射界面时放射光和折射光的偏振态.     

An Empirical Study of Nanowire Technological Trends

This paper follows a bibliometric method for nanowire case to make evident the technological trends; to present the relationship between patents; to help the researchers to discover relatively significant patents and to analyse important relationships between patents to identify those with most commercial potential and those which are critical technologies. This research focuses on the nanowire case study due to fact that this field is one of the most mature nanostructures and is one of the highly invested fields in nanotechnology. In terms of methodological approach, this study uses a different patent collection method than previous studies. This new method offers a new taxonomy that could make a significant impact on accurate patent data quests and increase the reliability of the patent analyses. As patent data are valuable sources of technology innovation and for forecasting technical change, this study utilises nanowire patent documents to pick out the technological trends, to identify nanowire technologies which both have the most commercial potential and which are critical at the organisational, national and international levels.     

金属DNA纳米线的制作方法

DNA分子的独特的双螺旋结构,使得DNA具有热力学上的稳定性、线性的分子结构及机械性等特征,是作为制备金属纳米线的理想模板。通过以DNA为模板形成金属纳米线,提高了DNA导电性,使得DNA分子作为纳米导线构筑纳米器件成为可能,在构筑生物纳米器件的领域会有广阔的应用前景。     

In situ growth of large-area and self-aligned graphene nanoribbon arrays on liquid metal

Intrinsic graphene features semi-metallic characteristics that limit its applications in electronic devices, whereas graphene nanoribbons (GNRs) are promising semiconductors because of their bandgap-opening feature. However, the controllable mass-fabrication of high-quality GNR arrays remains a major challenge. In particular, the in situ growth of GNR arrays through template-free chemical vapor deposition (CVD) has not been realized. Herein, we report a template-free CVD strategy to grow large-area, high-quality and self-aligned GNR arrays on liquid copper surface. The width of as-grown GNR could be optimized to sub-10 nm with aspect ratio up to 387, which is higher than those of reported CVD-GNRs. The study of the growth mechanism indicates that a unique comb-like etching-regulated growth process caused by a trace hydrogen flow guides the formation of the mass-produced self-aligned GNR arrays. Our approach is operationally simple and efficient, offering an assurance for the use of GNR arrays in integrated circuits.     

A cell electrofusion microfluidic device integrated with 3D thin-film microelectrode arrays

A microfluidic device integrated with 3D thin film microelectrode arrays wrapped around serpentine-shaped microchannel walls has been designed, fabricated and tested for cell electrofusion. Each microelectrode array has 1015 discrete microelectrodes patterned on each side wall, and the adjacent microelectrodes are separated by coplanar dielectric channel wall. The device was tested to electrofuse K562 cells under a relatively low voltage. Under an AC electric field applied between the pair of the microelectrode arrays, cells are paired at the edge of each discrete microelectrode due to the induced positive dielectrophoresis. Subsequently, electric pulse signals are sequentially applied between the microelectrode arrays to induce electroporation and electrofusion. Compared to the design with thin film microelectrode arrays deposited at the bottom of the side walls, the 3D thin film microelectrode array could induce electroporation and electrofusion under a lower voltage. The staggered electrode arrays on opposing side walls induce inhomogeneous electric field distribution, which could avoid multi-cell fusion. The alignment and pairing efficiencies of K562 cells in this device were 99% and 70.7%, respectively. The electric pulse of low voltage (～9 V) could induce electrofusion of these cells, and the fusion efficiency was about 43.1% of total cells loaded into the device, which is much higher than that of the convectional and most existing microfluidics-based electrofusion devices.     

基于正交表的准均匀设计

给出了利用正交表经过适当的几体旋转变换构造准均匀设计表的方法，准均匀设计基本上保持了正交设计的均匀分散和整齐可比性，而且每个因素的每个水平只做一次试验，因而特别适合地多水平的试验设计。     

Growth propagation of yeast in linear arrays of microfluidic chambers over many generations

The growth of microorganisms is often confined in restricting geometries. In this work, we designed a device to study the growth propagation of budding yeast along linear arrays of microfluidic chambers. Vacuum assisted cell loading was used to seed cells of limited numbers in the up-most chambers of each linear array. Once loaded, cells grow until confluent and then overgrow, pushing some of the newborns into the neighboring downstream chamber through connection channels. Such a scenario repeats sequentially along the whole linear chamber arrays. We observed that the propagation speed of yeast population along the linear arrays was strongly channel geometry dependent. When the connection channel is narrow and long, the amount of cells delivered into the downstream chamber is small so that cells grow over several generations in the same chamber before passing into the next chamber. Consequently, a population growth of more than 50 generations could be observed along a single linear array. We also provided a mathematical model to quantitatively interpret the observed growth dynamics.     

Cell structure minimization for incompletely specified cellular arrays of ROMs

Two new reduction techniques are presented for detecting equivalencies and redundancies in a given cellular array of ROMs and simplifying the cell structure. One of these techniques is related to the procedures for minimizing states in incompletely specified sequential machines.The first new procedure is developed as an extension of Biswas' procedure for minimizing the number of equivalent states and lateral signals. This generalized procedure applies to all classes of cellular arrays. The second reduction technique provides methods of detecting co-redundant states or lateral signals. This procedure is also generalized to apply to the more complex classes of cellular arrays. An illustrative example of each is included.     

完全有序的全同金属纳米点阵列的生长与研究

利用“幻数稳定团簇 模板”方法在半导体Si(111)衬底上第一次成功地外延生长出了尺寸相同、空间分布均匀的金属纳米团簇阵列。这种方法适用于不同的金属,制备出的纳米团簇阵列热稳定性非常高。用扫描隧道显微镜(STM)原位分析结合第一性原理计算确定了纳米团簇的原子结构以及阵列的形成机理。     

Simulation of single DNA molecule stretching and immobilization in a de-wetting two-phase flow over micropillar-patterned surface

We investigate single DNA stretching dynamics in a de-wetting flow over micropillars using Brownian dynamics simulation. The Brownian dynamics simulation is coupled with transient flow field computation through a numerical particle tracking algorithm. The droplet formation on the top of the micropillar during the de-wetting process creates a flow pattern that allows DNA to stretch across the micropillars. It is found that DNA nanowire forms if DNA molecules could extend across the stagnation point inside the connecting water filament before its breakup. It also shows that DNA locates closer to the top wall of the micropillar has higher chance to enter the flow pattern of droplet formation and thus has higher chance to be stretched across the micropillars. Our simulation tool has the potential to become a design tool for DNA manipulation in complex biomicrofluidic devices.     

Geometrical optimization of microstripe arrays for microbead magnetophoresis

Manipulation of magnetic beads plays an increasingly important role in molecular diagnostics. Magnetophoresis is a promising technique for selective transportation of magnetic beads in lab-on-a-chip systems. We investigate periodic arrays of exchange-biased permalloy microstripes fabricated using a single lithography step. Magnetic beads can be continuously moved across such arrays by combining the spatially periodic magnetic field from microstripes with a rotating external magnetic field. By measuring and modeling the magnetophoresis properties of thirteen different stripe designs, we study the effect of the stripe geometry on the magnetophoretic transport properties of the magnetic microbeads between the stripes. We show that a symmetric geometry with equal width of and spacing between the microstripes facilitates faster transportation and that the optimal period of the periodic stripe array is approximately three times the height of the bead center over the microstripes.