大功率晶闸管并联的物理级均流研究

针对常规电路级均流分析方法存在实现方式复杂、需要增加装置的不足，本文从场的角度出发，提出了一种物理级均流分析方法。该方法直接使用实物模型仿真，综合分析多物理场间的耦合作用，得到更加真实的均流分析结果。以大容量晶闸管并联实物模型为例，叙述了并联均流的物理级建模和仿真过程，在此基础上对均流母线的结构进行了改造，通过双排布置和不均匀分布两种措施显著提高了均流效果。     

基于等效建模的多尺度电磁计算技术研究进展

随着设计复杂度的提高和工作频率的提升,无线部件与系统的多尺度特性日益显著,它们的电磁仿真与优化均受制于多尺度电磁计算。在多尺度电磁计算中,精细结构的存在导致局部网格过密,这造成了系统矩阵病态和计算效率低下的问题。等效建模技术利用小尺度结构等效模型进行多尺度电磁计算,从而避免局部网格过密导致的系统矩阵病态问题。总结了多尺度电磁计算及等效建模的研究背景与现状,介绍了课题组针对多尺度电磁计算涉及的金属细线结构、低剖面天线等典型小尺度结构提出的等效模型,展示了等效建模技术在多尺度电磁计算中的应用及优势,并讨论了其未来发展趋势。     

基于参数化的防空武器平台系统仿真建模技术

针对防空武器平台仿真系统快速、高效建模需求,从多学科领域功能模型划分角度出发研究其仿真系统建模技术,建立了合理的领域功能模型划分框架及自底向上的系统多层建模结构;在此基础上结合多粒度参数化建模技术研究了通用领域功能模型建立方法。最后通过对某典型防空武器平台仿真系统的建模验证了该建模技术的有效性和可行性。     

脉冲多普勒雷达导引头仿真研究

从信号级仿真角度,介绍了脉冲多普勒雷达导引头仿真建模的基本技术思路和主要仿真模型的实现方法,结合具体仿真场景进行了动态仿真试验,并对试验结果进行了分析,为进一步开展雷达导引头干扰技术研究和雷达导引头抗干扰性能评估奠定了技术实现基础.     

面向卫星移动通信的系统级仿真平台设计与实现

针对卫星移动通信系统中对组网架构、协议体制和关键技术进行仿真论证的需求,设计了系统级仿真平台。首先介绍了系统级仿真平台架构,然后结合架构分析仿真平台的配置管理模型,对卫星、终端、信关站等核心通信节点进行建模,研究仿真平台工作流程,最后,通过多用户并发模式下随机接入过程仿真验证系统级仿真平台有效性。与传统方法相比,该仿真平台可适用于多星、多站、多波束、多链路和多用户自由组网,为卫星移动通信系统协议体制和关键技术的仿真验证提供了一种新的借鉴和参考。     

一种基于SystemC的片上网络辅助设计工具

提出了一种支持NoC建模与仿真的辅助设计工具,该工具基于SystemC设计,采用了混合精度的建模方式,支持周期级的NoC体系结构模型和随机流量模型,并且针对行为级应用建模提供了完善的支持,介绍了工具的实现方式及其支持的配置参数,详细阐述了基于进程网络模型的行为级应用建模、部署和协同仿真机制.     

纳米加工过程的分子动力学模拟技术研究

简要回顾了采用分子动力学方法模拟纳米加工过程的历史,介绍了分子动力学仿真方法的基本原理以及典型单晶体材料纳米切削机理的分子动力学仿真研究成果,并从模型建立、模拟尺度以及工件和刀具的影响等方面分析了纳米加工过程分子动力学模拟研究的最新进展。结果表明,建立三维大规模及多尺度的纳米加工仿真模型已经成为目前研究的主要方向;工件和刀具对纳米加工影响的研究也逐渐深入,涉及工件的晶向、缺陷以及刀具参数和磨损等方面的问题。     

光传送网建模与价值评估

文章针对光传送网的规划与建设中,对光纤通信网络工作原理以及价值评估体系进行分析和建模,从底层物理出发,建立三种调制格式的仿真模型和光传送链路仿真模型,求解不同调制格式的信噪比及误码率容限点的跨段数,并从仿真实验角度验证了理论推导合理性,基于光纤的信息容量和传输距离,建立多目标优化模型,求解得最优网络规划方案,为我国城市群制定光传送网规划,采用约束法,以光纤总距离最短为约束目标,求解其余目标最优的网络规划的非劣解,最后综合考虑了传输距离,传输容量、网络拓扑等各种因素,寻找到最大化网络的价值的光传送网链路设计。     

3G无线网络系统级仿真与网络规划

系统级仿真是3G无线网络规划不可缺少的重要手段。文章首先介绍了系统级仿真的基本概念，然后论述了系统级仿真建模，并将静态系统仿真和动态系统仿真进行了对比。最后，从网络规划应用的角度，对系统级仿真方法的选择进行了讨论。     

基于层次化建模的多粒度电台仿真模型

针对信息化条件下对多粒度通信装备模型的需求,论述了多粒度的有关概念和常用的多粒度建模方法,提出层次化多粒度建模方法和电台模型多粒度的划分方法,构建了信号级和子系统级电台发信机模型,最后通过仿真工具SIMULINK对两种粒度发信机模型产生的信号进行了仿真,对多粒度通信装备模型的研究提供了一种思路。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.     

High-quality single-crystal CdSe nanoribbons and their optical properties

Large-scale synthesis of single-crystal CdSe nanoribbons is achieved by a modified thermal evaporation method, in which two-step-thermal-evaporation is used to control CdSe sources＇ evaporation. The synthesized CdSe nanoribbons are usually several micrometers in width, 50 nm in thickness, and tens to several hundred micrometers in length. Studies have shown that high-quality CdSe nanoribbons with regular shapes can be obtained by this method. Room-temperature photolumines-cence indicates that the lasing emission at 710 nm has been observed under optical pumping （266 nm） at power densities of 25-153 kW/cm^2. The full width half maximum （FWHM） of the lasing mode is 0.67 nm     

Propagation of hermite-cosh-gaussian beams passing through ABCD optical system with an annular aperture

By using the expansion of the aperture function into a finte sum of complex Gaussian functions, the corresponding analytical expressions of Hermite-cosh-Gaussian beams passing through annular apertured paraxially and symmetrically optical systems written in terms of ABCD matrix were derived, and they could reduce to the cases with squared aperture. In a similar way, the corresponding analytical expressions of cosh-Gaussian beams through annular apertured ABCD matrix were also given. The method could save more calculation time than that by using the diffraction integral formula directly.     

Influence of polarization extinction ratio on distributed polarization coupling detection

Distributed polarization coupling in polarization-maintaining fibers can be detected by using a white light Michelson interferometer. This technique usually requires that only one polarization mode is excited. However, in practical measurement, the injection polarization direction could not be exactly aligned to one of the principal axes of the PMF, so the influence of the polarization extinction ratio should be considered. Based on the polarization coupling theory, the influence of the incident polarization extinction on the measurement result is evaluated and analyzed, and a method for distributed polarization coupling detection is developed when both two orthogonal eigenmodes are excited.     

Call for Papers

正Communications—VLSI Researches and industries of telecommunications have been growing rapidly in the last 20 years and will keep their high growing pace in the next decade.The involved researches and developments cover mobile communications,highway and last-mile broadband communication,domain specific communications,and emerging D2D M2M communications.Radio communication steps into its