激光等离子体声波及应用

本文简要介绍了激光等离子体声波的产生机理、特性应用前景。     

FPGA实现的电子内窥镜与计算机接口

介绍了一种新型的可编程逻辑器件ＦＰＧＡ及其开发工具ＭＡＸ＋ＰＬＵＳⅡ,并使用ＦＬＥＸ１０Ｋ３０开发了电子内窥镜系统与计算机ＩＳＡ总线的接口系统,并说明系统的结构和工作原理。     

一种基于交换机的彩铃业务实现方案

首先介绍了在GSM移动网络中实现彩铃业务的原理，然后提出一种基于交换机实现彩铃业务的技术方案，分析了此方案中媒体设备的物理结构和内部信令的交互过程，最后将该方案与基于智能网的方案进行了对比。     

Phenoxazine-based organic dyes with different chromophores for dye-sensitized solar cells

A series of organic dyes (POZ-2, POZ-3, POZ-4 and POZ-5) involving phenoxazine were synthesized as sensitizers for application in dye-sensitized solar cells (DSSCs). For comparison, three different electron donors namely 10-phenyl-10H-phe-nothiazine, 10-phenyl-10H-phenoxazine and triphenylamine were separately appended onto the 7-position of the model dye (POZ-2). The obtained four dyes exhibit considerably high values of conversion efficiencies of 6.6%, 7.8%, 7.1% and 6.4%, respectively, under the simulated AM1.5G conditions. The geometries of the dyes were optimized to gain insight into the molecular structure and electron distribution, and then the charge extraction and transient photovoltage decay measurements were further performed to understand the influence of electron donors on the photovoltaic behaviors.     

Temperature dependence of lasing characteristics forlong-wavelength (1.3-μm) GaAs-based quantum-dot lasers

Data are presented on the temperature dependence of 1.3-μm wavelength quantum-dot (QD) lasers. A low-threshold current density of 90 A/cm² is achieved at room temperature using high reflectivity coatings. Despite the low-threshold current density, lasing at the higher temperatures is limited by nonradiative recombination with a rapid increase in threshold current occurring above ~225 K. Our results suggest that very low threshold current density (⩽20 A/cm ²) can be achieved at room temperature from 1.3-μm QD lasers, once nonradiative recombination is eliminated     

具有零相关窗互补地址码的设计

该文给出并证明了构造零相关窗(ZCW)互补码的二叉树方法,当码字足够长时这种方法构造的码字数与理论上界的数目最多仅相差1。为了增加可用的码字,采用互补码与扩展矩阵直积的方法,将一个互补码构造成一组码,组内码字的相关特性取决于扩展矩阵,但不同组之间的码字仍有ZCW。     

Self‐Assembly of Nanostructured,Complex, Multication Films via Spontaneous Phase Separation and Strain‐Driven Ordering

Spontaneous self‐assembly of a multication nanophase in another multication matrix phase is a promising bottom‐up approach to fabricate novel, nanocomposite structures for a range of applications. In an effort to understand the mechanisms for such self‐assembly, complimentary experimental and theoretical studies are reported to first understand and then control or guide the self‐assembly of insulating BaZrO₃ (BZO) nanodots within REBa₂Cu₃O_7–δ (RE = rare earth elements including Y, REBCO) superconducting films. The strain field developed around BZO nanodots embedded in the REBCO matrix is a key driving force dictating the self‐assembly of BZO nanodots along REBCO c‐axis. The size selection and spatial ordering of BZO self‐assembly are simulated using thermodynamic and kinetic models. The BZO self‐assembly is controllable by tuning the interphase strain field. REBCO superconducting films with BZO defect arrays self‐assembled to align in both vertical (REBCO c‐axis) and horizontal (REBCO ab‐planes) directions result in the maximized pinning and J_c performance for all field angles with smaller angular J_c anisotropy. The work has broad implications for the fabrication of controlled self‐assembled nanostructures for a range of applications via strain‐tuning.     

Versatile Graphene‐Promoting Photocatalytic Performance of Semiconductors: Basic Principles,Synthesis, Solar Energy Conversion,and Environmental Applications

Graphene‐semiconductor nanocomposites, considered as a kind of most promising photocatalysts, have shown remarkable performance and drawn significant attention in the field of photo‐driven chemical conversion using solar energy, due to the unique physicochemical properties of graphene. The photocatalytic enhancement of graphene‐based nanocomposites is caused by the reduction of the recombination of electron‐hole pairs, the extension of the light absorption range, increase of absorption of light intensity, enhancement of surface active sites, and improvement of chemical stability of photocatalysts. Recent progress in the photocatalysis development of graphene‐based nanocomposites is highlighted and evaluated, focusing on the mechanism of graphene‐enhanced photocatalytic activity, the understanding of electron transport, and the applications of graphene‐based photocatalysts on water splitting, degradation or oxidization of organic contaminants, photoreduction of CO₂ into renewable fuels, toxic elimination of heavy metal ions, and antibacterial applications.     

光子晶体调制半导体激光器侧模

为了实现半导体激光器的单侧模稳定工作,提出了一种在激光器的脊条两侧引入光子晶体结构滤除半导体激光器高阶侧模的方法。通过调整激光器上表面的刻蚀深度、光子晶体区域的条宽和间隔来改变激光器内部的模场分布,同时结合选择性的载流子注入来增强基模的激射优势,进而减少侧模的数量。实验上制作了主脊条宽度为6 m,光子晶体周期5 m,波长1 550 nm的半导体激光器。测试结果表明:在连续工作的情况下,电流300 mA的时候,高阶侧模受到抑制,水平发散角变为10.2,证实了光子晶体结构调制激光器侧模的可行性。     

Co3O4 Nanoparticles as Robust Water Oxidation Catalysts Towards Remarkably Enhanced Photostability of a Ta3N5 Photoanode

Despite the fact that Ta₃N₅ absorbs a major fraction of the visible spectrum, the rapid decrease of photocurrent encountered in water photoelectrolysis over time remains a serious hurdle for the practical application of Ta₃N₅ photoelectrodes. Here, by employing a Co₃O₄ nanoparticle water oxidation catalyst (WOC) as well as an alkaline electrolyte, the photostability of Ta₃N₅ electrode is significantly improved. Co₃O₄/Ta₃N₅ photoanode exhibits the best durability against photocorrosion to date, when compared with Co(OH)_x/Ta₃N₅ and IrO₂/Ta₃N₅ photoanodes. Specifically, about 75% of the initial stable photocurrent remains after 2 h irradiation at 1.2 V vs. RHE (reversible hydrogen electrode). Meanwhile, a photocurrent density of 3.1 mA cm^?2 has been achieved on Co₃O₄/Ta₃N₅ photoanode at 1.2 V vs. RHE with backside illumination under 1 sun AM 1.5 G simulated sunlight. The reason for the relatively high stability is discussed on the basis of electron microscopic observations and photoelectrochemical measurements, and the surface nitrogen content is monitored by X‐ray photoelectron spectroscopic analysis.