数模转换器的EWB仿真分析与研究

为解决实际电子产品设计和开发过程中的问题,以EWB仿真软件为例,详细讨论了D/A数模转换电路和集成DAC芯片的仿真。根据仿真结果得知:温度的影响:当温度从0℃升高到100℃的过程中,输出电压快速升高,最后波动幅度逐渐减小,趋于恒定;电路参数的影响:当R1从1kΩ线性增大到10kΩ,初始输出线性升高,后由于非线性失真趋于恒定,因此设计倒T形电路网络D/A转换器时需注意电阻的精确度。对于集成DAC,当数字输入值较高时转换精度下降。     

A mathematical model to analyze heat and mass transfer characteristics of a CPL evaporator porous wick

A capillary pumped loop (CPL), because of its high power thermal transport character, has been developed as an attractive system for the thermal discharge of electronic chips with high power loads, especially on spacecrafts. A working fluid having relatively larger heat of evaporation, methanol for example, may transfer significant heat flux. In this paper a new mathematic model is constructed, in which the most important character is the treatment or the unsaturated region of the evaporator porous wick. Numerical simulation of heat and mass transfer in the evaporator porous wick is carried out with a new three‐layer model. The importance of unsaturated layer to simulate the present problem is clear. © 2005 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(4): 209–218, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20066     

Probing the electromagnetic field distribution within a metallic nanodisk

A Co nanolayer is used as a local probe to evaluate the vertical inhomogeneous distribution of the electromagnetic (EM) field within a resonant metallic nanodisk. Taking advantage of the direct relation between the magneto-optical activity and the electromagnetic field intensity in the Co layer, it is shown that the nonuniform EM distribution within the nanodisk under plasmon resonant conditions has maximum values close to the upper and lower flat faces, and a minimum value in the middle.     

Synthesis and electrophoretic deposition of hydrothermally synthesized multilayer TiO2 nanotubes on conductive filters

TiO₂ nanotubes were synthesized by the decomposition of titanium isopropoxide in water and the calcination at 450 °C for 2 h to form TiO₂ nanoparticles. The synthesized TiO₂ in anatase form nanoparticles were processed hydrothermally in 10 M NaOH solution at 130 °C for 24 h to obtain multilayer TiO₂ nanotubes. TEM analysis revealed that the diameters of the tubes were around 10 nm and they are in the length of 100 nm. Subsequently, colloidal suspensions containing 1% wt. Of TiO2 nanotubes were prepared with TEA and butanol and electrophoretic deposition (EPD) experiments were conducted in order to obtain coatings on Ni and carbon filters using a deposition time of 10 min. and an applied voltage of 65 V. It is also shown that multilayer TiO₂ nanotubes having outer diameter around 10 nm and inner diameters of 4.3 nm can be produced using the described technique. EPD is also shown to be an effective technique to coat three dimensional components, such as Ni and C filters for various applications including water and air purification systems.     

Virtual community-based video resource sharing solution in MANETs

The virtual community has emerged as a state-of-the-art technology, grouping the user with the common interest and providing a feasible solution for large-scale deployment of resource sharing services. Efficient sharing for video resources and low maintenance cost of overlay topology are key factors in MP2P video on demand systems. In this paper, a novel virtual community-based video resource sharing (VCVRS) solution in MANETs is proposed. VCVRS design a virtual community construction strategy to group the nodes with the common playback behavior and a flexible community maintenance mechanism so as to obtain the fast supplier discovery and low maintenance overhead. Simulation results show how VCVRS achieves higher lookup success rate, lower server stress, lower node load and less overlay maintenance overhead, in comparison with another state of the art solution.     

SED-A9C主板PS/2接口的实现

本文介绍基于EP9315处理器开发的SED-A9C主板PS/2键盘接口的实现方法,对Cirrus Logic公司发布的在Linux操作系统下的PS/2键盘驱动程序进行分析,找出相应的漏洞,并给予解决。