嵌入式处理器和嵌入式操作系统研究概述

随着计算机技术和通讯技术的快速发展,嵌入式系统已经广泛渗入到工业控制、移动通信、电子商务、信息家电等多个应用领域,应用日益广泛。因此,该文从嵌入式系统处理器和嵌入式操作系统两方面研究了嵌入式系统特点。     

盐水杂质对隔膜氯碱电槽性能的影响

具有沉积石棉隔膜的实验电槽使用不纯盐水来研究硬度对电槽性能的影响。氢氧化钠在隔膜中的浓度分布状态是由扩散、迁移和湍流三种因素来确定的;应该指出的是:在隔膜电槽的操作条件下,迁移流比扩散流要大得多。生产氯气和纯净烧碱用汞齐法水银电槽是最好的生产方法。可是,目前几乎没有再听到汞齐法水银新电槽的建设,尤其是日本,由于汞法污染环境的关系,倒是有许多水银电槽工厂正在转化为隔膜电槽,估计当今世界的硬度。     

滴流床反应器:综述(Ⅲ)

<正> 反应器设计:液体分布 对吸收塔中的液体分布已有广泛的研究。这些资料用于滴流床中具有其局限性,因为操作条件通常不同。因此,以下讨论只限于滴流床研究。     

Meeting approval

Each of the five conference centers featured here displays the best its parent organization has to offer. Take a tour through Herman Miller, Inc.'s Marigold Lodge; UCLA Conference Center/Bruin Woods Family Resort, S.C. Johnson & Son, Inc.'s The Council House; Aetna Institute for Corporate Education; & Eastwood (Medical Center) Conference Center & discover conference dining's multifaceted mission.     

A new technique to study transient conductivity under pulsed monochromatic light in Cr-doped GaAs using acoustoelectric voltage measurement

The transient conductivity of high-resistivity, Bridgman grown, Cr-doped GaAs under pulsed monochromatic light is monitored using transverse acoustoelectric voltage (TAV) at 83 K. Keeping the photon flux constant, the height and transient time constant at the TAV are used to calculate the energy dependence of the trap density and its cross section, respectively. Two prominent trap profiles with peak trap densities of approximately 10(17) cm(-3) eV(-1 ) near the valence and the conduction bands are detected. These traps have very small capture cross sections in the range of 10(-23 )-10(-21 )cm(2). A phenomenon similar to the persistent photoconductivity with transient time constants in excess of a few seconds (in some cases, a few hundred seconds) in high-resistivity GaAs at T=83 K is also detected using this technique. These long relaxation times are readily explained by the spatial separation of the photo-excited electron-hole pairs and the small capture cross section and large density of trap distribution near the conduction band. The technique is nondestructive and, because of the dependence of the polarity of the acoustoelectric voltage on the carrier type, it yields information about the charge of the transient carriers and the type of deep traps involved in the release or trapping of these carriers.     

Electric cadavers, 'metiphor,' and other medical software marvels

"Grateful Med," "Fluids," "Metiphor," virtual reality, and electric cadavers are just some of the programs and buzzwords in the futuristic world of medical software affecting many areas of health care.     

Characterization of piezoceramics

A 3-D approach to piezoelectric material characterization, based on the assumption that the coordinate axes are pure mode propagation directions, is described. In this case the general equations simplify and an analytical solution can be achieved. For two geometrical shapes (rectangular and cylindrical), stress and strain tensor components and the electrical impedance of the sample are obtained. These 3-D equations show that the wave velocities and permittivity are intrinsic parameters of the medium and do not depend on either the sample geometry or the mode that is considered. This was not true for the 1-D models where the wave velocities and permittivity are different for each of the modes or geometries.     

Lifecare

Foodservice has become a major attraction in lifecare communities, the fastest growing segment of the senior citizens housing market.     

Polybrominated Diphenyl Ethers in Surface Sediment from Songhua River Basin, Northeast of China

Sixty sediment samples were collected from the main Songhua River in three years. Twelve polybrominated diphenyl ether ( PBDE) congeners ( BDE17, 28, 47, 66, 99, 100, 153, 154, 138, 183, and BDE?209) w...