基于CFD软件的电力电子设备强制风冷散热的数值模拟

随着电力电子技术的发展,对电力电子设备散热问题的研究日益重要。该文运用CFD软件对电力电子设备的强制风冷散热进行数值模拟研究,得出简单可行的散热方案,为设备的散热设计提供一定的依据,提高设备的可靠性。     

船载高频分系统的热设计

由于电子元器件的小型化、集成化,其热流密度越来越高,对电子设备进行合理的热设计也越来越重要。而工程实际应用中可供选择的散热方法有很多,每种散热方法都有各自的优点与不足。针对以往设计中的不足,经过认真分析,设计了全新的结构形式与散热方式,使其在满足使用要求的前提下,简化了散热系统,提高了设备的可靠性。     

一种新型无机传热元件

随着电子设备的结构越来越紧凑,组装密度越来越高,功耗越来越大,设备的散热问题越来越严重,传统的热设计技术已很难满足其要求,应积极跟踪并应用新的热设计技术,以满足现代电子设备的发展需要.对一种新型无机传热元件的工作原理进行了详细说明,对其传热效果进行了验证,给出了应用实例,可供从事军用电子设备研制的设计人员参考.该传热元件能有效解决大功率设备和密封设备的散热问题,从而确保设备工作的稳定性,提高其可靠性.     

BGA热性能仿真优化分析方法研究

随着科技的进步,电子设备也向着集成度更高、功率更大、可靠性要求更严格的方向发展。高温引起的电子设备失效作为最常见的失效原因之一,也越来越引起设计者的重视。通过常规的制备样品反复试验的方法耗时耗力,而采用仿真模拟的办法就能很好地解决问题。文章从使用高导热封装材料、添加散热盖和改善封装结构等方面,应用仿真模拟的手段来比较各种优化设计的改善程度,在散热优化方面为今后的BGA设计提供了参考。     

机载电子设备DDS模块散热工艺设计

首先简要介绍了电子设备内部印制电路四种散热结构设计：冲击式、冷板式、平板热管式、空心板式。根据机载的要求一质量轻、体积小、耐振动冲击、可靠性高以及器件局部发热大等实际要求，结合发热器件AD9854ASQ的封装形式，提出3-D散热工艺设计，即采用导热柱、印制电路布线设计、SMT焊接等，使发热器件AD9854ASQ的发热有效散逸。     

电磁干扰与电子通信设备机箱机柜的结构设计研究

由于电子通信设备的电磁兼容和散热问题,给电子设备机柜机箱的设计提出了不同一般机电产品的要求,加强研究电子设备机箱机柜的结构,解决机柜内电子器件的良好散热,防止电路模块间的电磁干扰,是保证电子设备正常稳定连续运行的重要手段.     

某电子设备热控系统的设计

为解决电子设备的散热问题,对某电子设备的热控系统进行了设计,采取了加导热片、填充导热填料等高可靠性导热方式进行散热,并在HyperMesh软件中建立了有限元模型,通过Patran/Nastran软件进行了仿真计算。计算结果表明,采取热控措施后印制板及元器件温度降低,且分布更加均匀,验证了热控系统设计的合理性。     

便携式密封电子设备的自然散热设计

对便携式密封电子设备的自然散热设计进行了介绍,分析了影响设备温度的因素,阐述了密封电子设备自然散热设计的要点,使用热分析软件ANSYS-Icepak进行仿真,提出的利用隔热板分隔散热区域的设计思路,设计了铝板嵌铜的底板,平衡了散热能力与重量的矛盾,优化了机箱外壳结构参数,对散热肋片进行了减重设计。仿真和实验表明,某便携式超短波设备功耗146 W,在环境温度55℃条件下的满足散热要求,同时将整机重量控制在15 kg以内。     

基于Solidworks的负载器热设计与分析

不同功率大小的电子设备集成化机箱在工作时,元器件工作温度上升最高可达130℃,器件根本无法工作。基于此问题,提出了一种叠加散热方案,设计了负载器功率器件的散热结构,详述了仿真模型的边界条件设定等操作。结果表明,在结合改进结构与风机的散热方式下,能保证功率元器件的最高温度处于规定的温度范围内,满足了其对可靠工作的温度要求。增加散热条件以后,元器件工作温度能稳定在55°左右,保证了设计的可靠性与可行性。     

DC/DC电源模块散热器的设计及热分析

温度是影响DC/DC电源电路可靠性的重要因素之一。高、低温及其循环会对大多数电子元器件产生严重影响。它会导致电子元器件的失效,进而造成电源整机的失效。多芯片模块(MCM)和高密度三维组装技术的出现使得电子设备的热流密度越来越高。科学合理地设计电子设备以满足其热性能的要求在电源模块设计中至关重要。热管具有一种高效的传热能力,配以合理散热鳍片,将提高散热器的散热效果。本文以数值传热理论为基础,通过3D设计软件Solidworks建立一套DC/DC电源模块的散热器模型,并利用热流分析软EFD.Pro对电源模块进行热分析仿真技术研究。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first