金纳米粒子的图案化组装及表面增强拉曼光谱研究

利用聚苯乙烯纳米粒子有序组装结构为模板,进行了金纳米粒子的图案化组装。金纳米粒子在聚苯乙烯纳米粒子底部自组装聚集,形成规则的“面包圈”结构。表面增强拉曼光谱表明,相对于随机分布的金纳米粒子而言,金纳米粒子组装结构具有聚焦电磁场作用,从而使吸附的对巯基苯甲酸的拉曼散射得以进一步增强。     

种子法制备三角形银纳米粒子及其性能表征

 以十六烷基三甲基溴化胺(CTAB)为软模板剂，采用种子法制备出三角形银纳米粒子，应用透射电镜、能量散射X射线谱仪、紫外 可见分光光度计研究了粒子的性能。结果表明：所得三角形银纳米粒子是面心立方单晶，边长随着种子加入量的减少而递增，可在20～100 nm范围内调节；CTAB以薄膜形式包覆于粒子表面阻止其氧化，粒子胶体的吸收光谱呈现典型的三角形粒子吸收峰。用扫描电镜观测到粒子在硅片上自组装成一定的2维阵列结构。     

纳米Cu/Al_2O_3组装体模板合成与光吸收

以有序的多孔氧化铝为模板,利用交流电在孔洞中沉积金属铜得到纳米Cu粒子/Al2O3组装体系.透射电镜观察显示随着交流电沉积时间的延长,孔洞中纳米Cu粒子数量增加.测量了纳米Cu粒子/Al2O3组装体系的紫外可见光吸收光谱,发现随着孔洞中纳米Cu粒子数量增加,纳米Cu粒子/Al2O3组装体系的吸收带边大幅度红移;根据雷利散射引起的消光增强解释了组装体吸收带边红移的原因.同时发现Cu粒子的表面等离子共振吸收峰消失及组装体在吸收带边区光吸收值满足间接带隙半导体光吸收边的表达式.     

钴纳米粒子自组装有序阵列与磁性

采用高温液相分解法制备出平均粒径不同的单分散的钴纳米粒子.用自组装的方法得到二维和三维的钴纳米粒子有序阵列，用透射电子显微镜研究了粒径、温度、有机溶剂以及浓度对钴纳米粒子的自组装的影响.用超导量子干涉仪研究了钴纳米粒子的超顺磁性.这些研究结果为深入研究磁性纳米粒子的物性和在纳米器件中的应用奠定了良好的基础. 关键词： 钴纳米粒子 自组装 超顺磁性     

金纳米粒子上CdS纳米半导体材料的制备

利用电极表面组装金纳米粒子为模板,通过循环扫描电化学沉积CdS,在电极表面构筑CdS@Au的核-壳纳米结构。结果表明,在实验条件下所得的CdS均属六方相,但CdS的型貌强烈依赖于电化学沉积扫描电位。金纳米粒子表面的CdS包裹层导致其表面等离子体共振红移,这与金属粒子周围介质折射系数的改变以及粒子内部电荷密度分布的变化密切相关。     

单分散“核-卫星”金纳米结构的DNA控制组装：一种新型的纳米分级组装模块

报道了一种单分散“核-卫星”纳米金簇状结构的构造方法,不但可以有效调节卫星粒子的数目,还能实现核与卫星粒子间距离的准确控制. 利用DNA分子高度可控的程序化自组装性能,通过合理控制组装过程中核与卫星粒子表面的DNA修饰密度以及不同金纳米粒子的化学计量比,实现了单分散核-卫星结构的高产率组装,结合使用凝胶电泳这一高效的纳米分离技术实现了目标产物的分离. 该方法保证了卫星粒子表面极低的DNA覆盖率,使其与蛋白分子中的巯基基团具有较强的化学亲和作用,使得金纳米粒子在蛋白功能化石墨烯表面的二维层次化自组装得以实现.     

CdS纳米粒子的自组装单分子膜制备研究

利用疏基乙酸与草酸的混合自组装单分子膜成功制备了粒径分布均匀的CdS纳米粒子，并用SEM，XRD，XPS，PL对样品进行了表征。SEM表明形成在自组装单分子膜表面上的CdS纳米粒子的平均粒径约为45nm。XPS表明在自组装单分子膜表面形成了CdS纳米粒子。PL谱表明CdS纳米粒子在675nm有一峰值波长，我们认为这一发光是由表面缺陷造成的。     

十八胺LB膜吸附组装金纳米颗粒研究

制备了十八胺单层、多层LB膜及粒径为几个纳米的金纳米粒子。pH值小于10.3时十八胺带正电荷,将其置于金纳米溶胶(pH值10.3)中,带负电荷的金纳米粒子与带正电荷的十八胺之间通过静电作用,金纳米颗粒被成功地吸附组装到十八胺LB膜中,形成纳米薄膜。紫外-可见光谱、红外光谱及扫描电镜显示:金纳米颗粒通过这种方法能够很好的组装在十八胺LB膜上,且其组装层整齐有序,同时也受十八胺LB膜层数及组装时间的影响。     

桑色素修饰金纳米粒子自组装膜的制备及其性能研究

采用水相硅烷化方法,将γ-氨基丙基三乙氧基硅烷[H2N(CH2)3Si(OC2H5)3](APES)组装在石英表面,在基底表面修饰上氨基为末端的单层膜,并进一步在这种功能化的单层膜基底上组装金纳米粒子得到金纳米粒子/APES/石英的纳米复合结构.以制备的金纳米粒子自组装膜修饰石英为基底及DL-半胱胺酸为中介,利用桑色素(Morin)和DL-半胱胺酸的化学吸附作用,将桑色素间接组装在金纳米粒子自组装膜修饰石英基底表面,所构建的桑色素修饰金纳米粒子自组装膜对三苯基锡有灵敏的荧光识别作用.文章着重研究了桑色素修饰金纳米粒子自组装膜的制备以及组装条件对其荧光行为的影响,探讨了膜的响应特性及响应机理.     

纳米结构的制备及单电子器件研究

建立了单电子器件的制备工艺和单电子器件的分析、测量系统,研究了有潜在应用价值的纳米结构加工技术,制备了适合光电集成的多种纳米结构,发展了常规光刻法制备单电子器件的多种技术,其中,在生命科学和信息领域有着广泛应用的“纳米电极对”引起了国内外专家的重视,发展以“纳米电极对”为基础的单电子器件及其应用是我们目前的主要研究方向,目前我们正在探索这种单电子器件在生命芯片、微电子系统集成方面的应用。     

Scalable bottom‐up assembly of suspended carbon nanotube and graphene devices by dielectrophoresis

Bottom‐up assembly by dielectrophoresis (DEP) has emerged in recent years as a viable alternative to conventional top–down fabrication of electronic devices from nanomaterials, particularly carbon nanotubes and graphene. Here, we demonstrate how this technique can be extended to fabricate devices containing carbon nanotubes and graphene suspended between two electrodes over a back‐gate electrode. The suspended device geometry is critical for the development of nano‐electromechanical devices and to extract maximum performance out of electronic and optoelectronic devices. This technique allows for parallel assembly of devices over large scale. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Invited Review: DNA-mediated artificial nanobiostructures: state of the art and future directions

DNA (deoxyribonucleic acid)-mediated assembly of nanometer and micrometer scale structures can have a profound impact in the fields of nanoelectronics and nanotechnology. Such structures can also find applications in microelectromechanical systems, hybrid bio-sensors, and the potential to continue the scaling of Moore’s law beyond the 50 nm node. While engineers and scientists have been long aspiring to controllably and specifically manipulate structures at the micrometer and nanometer scale, nature has been performing these tasks and assembling structures with great accuracy and high efficiency using highly specific biological molecules such as DNA and proteins. This paper describes the motivations and fundamentals behind these assembly concepts, with a focus on DNA hybridization-mediated assembly, and presents the state of the art in this field. In addition, new ideas and directions for future research on DNA-mediated assembly of active devices and DNA-based molecular devices are also presented.     

金纳米棒的飞秒激光组装研究

金属纳米粒子对于研究表面等离子体共振具有非常重要的意义,其自组装形成的功能组装体能够展现出更加优异的整体协同性能.本文通过飞秒激光加工对金纳米棒直接进行组装,不引入其它的修饰剂,过程简单、快速(约1 min),不仅保留了金纳米棒表面等离子特性,且可以实现金纳米棒的任意精细图案化.将组装的微纳结构用于微流控芯片表面增强拉曼散射探测,可以得到很好的增强效果,为等离子体器件的制备提供了新的方法.     

Massively parallel low-cost pick-and-place of optoelectronic devices by electrochemical fluidic processing

We describe a novel electrochemical technique for the nonlithographic, fluidic pick-and-place assembly of optoelectronic devices by electrical and optical addressing. An electrochemical cell was developed that consists of indium tin oxide (ITO) and n -type silicon substrates as the two electrode materials and deionized water (R = 18 MOmega) as the electrolytic medium between the two electrodes. 0.8-20-microm-diameter negatively charged polystyrene beads, 50-100-microm-diameter SiO(2) pucks, and 50-microm LED's were successfully integrated upon a patterned silicon substrate by electrical addressing. In addition, 0.8-microm-diameter beads were integrated upon a homogeneous silicon substrate by optical addressing. This method can be applied to massively parallel assembly (>1000 x 1000 arrays) of multiple types of devices (of a wide size range) with very fast (a few seconds) and accurate positioning.     

用分子自组装技术制备的单电子器件的Monte Carlo模拟

用分子自组装技术制备出纳米金单电子器件,并测量了其伏安特性,根据单电子系统的半经典理论,用MonteCarlo法对其结果进行了模拟.结果表明,模拟出的伏安曲线与实测的伏安曲线有较好的一致性,反映了模拟方法用于单电子器件研究的合理性,此外发现,虽然单电子器件两电极间含有众多的纳米粒子,但在低压区,其伏安特性只与少数纳米粒子有关 关键词： 单电子器件 MonteCarlo模拟 分子自组装     

Physical limits on computation by assemblies of allosteric proteins

Assemblies of allosteric proteins are the principle information processing devices in biology. Using the Ca2+-sensitive cardiac regulatory assembly as a paradigm for Brownian computation, I examine how system complexity and system resetting impose physical limits on computation. Nearest-neighbor-limited interactions among assembly components constrain the topology of the system's macrostate free energy landscape and produce degenerate transition probabilities. As a result, signaling fidelity and deactivation kinetics cannot be simultaneously optimized. This imposes an upper limit on the rate of information processing by assemblies of allosteric proteins that couple to a single ligand type.     

Miniature liquid-crystal-on-silicon display assembly

A novel integrated assembly process for miniature liquid-crystal-on-silicon displays using photodefinable benzocyclobutene resin is presented. Spin coating speed defines the cell gap, photolithography defines the cell perimeter and spacers, and thermocompression bonding provides the adhesion. The photodefined adhesive spacers provide thin liquid-crystal cell gap control (<2.5 microm) with excellent uniformity (+/-100 nm) for glass-on-glass and glass-on-silicon assemblies. The resin is compatible with common liquid-crystal alignment films and exhibits a bonding shear strength of 22+/-3.2 MPa The assembly process flow and characterization of demonstration devices are described.     

光锥与CCD耦合效率的理论分析

光锥与CCD的耦合技术是研制ICCD图像传感器的关键技术,本文主要从理论上分析并讨论了光锥与CCD耦合器件的耦合效率及其影响因素,进一步分析讨论了耦合效率对耦合器件信噪比的影响.证明了光锥与CCD的耦合效率不仅降低ICCD探测效率而且降低ICCD信噪比,并提出了提高光锥与CCD耦合效率的方法和途径.     

HL-2M 装置集成安装进度控制研究

大型托卡马克装置集成安装工程子项多、接口繁多、工作空间狭小、系统复杂、参与人员众多,如 何做好装置集成安装的进度控制至关重要。基于工程进度风险管理思维,详细分析了 HL-2M 装置集成安装进度 控制风险因素,并探索了进度控制体系有效运行方式,为安装进度风险可控且实现进度控制目标提供了保障,也 为我国大型磁约束核聚变装置集成安装标准化和规模化发展积累了经验。     

The application of semiconductor diode lasers to the soldering of electronic components

Work being carried out at the University of Hull into the application of high power laser diodes to the soldering process is described. The commercial availability of semiconductor diode lasers has brought an exciting new soldering tool to the manufacturers of electronics assemblies: trends in electronics assembly are to increasingly high-density interconnections and increasing device functionality. Packages are reducing in size and pin-out counts are increasing. Currently 0.010–0.016 inch lead pitch devices are being introduced by many manufacturers. Lasers can be used with advantage in the soldering of such fine and precise devices and high-power semiconductor laser diodes can be used to build compact, flexible and controllable soldering units. With computer control of the power and duration of the laser energy it is possible to ensure consistent and reliable soldering. To achieve this, however, the various parameters involved in the laser beam-solder assembly interaction need to be carefully defined. This paper reports on our identification of these parameters and the salient design features of an automated diode laser soldering system.