Influence of Samarium on Learning and Memory Function of Rats

Sixty-four Spraque-Dawley(SD)big rats with weaning weight of (195±15) g were randomly divided into 4 groups with 8 males and 8 females each group. One group drunk with de-ionized water served as control and was also used for analysis of the background. The other three groups rats were raised by de-ionized water containing low, middle and high concentrations of Sm for four months, then learning and memory tests were carried out in Y-electric maze. Compared with the control rats, the learning and memory of rats in low and middle groups shows a deterioration trend, exhibiting the function degradation of rats' brain. It may results from the rare earth elements through blood-brain barrier affecting the normal physiological functions of rats' brain. In addition, the activity of superoxide dismutase (SOD) in rats' brain decreases, while the content of malondialdehyde (MDA) concentration increases. The decreased SOD activity and the increased MDA mean the degeneration the ability of anti-oxidation in rats' brain, which are accordance with the degradation of learning and memory function of rats in low and middle Sm groups.     

Red Emitting Phosphor (Y,Gd)BO3:Eu3+ for PDP Prepared by Complex Method

Red phosphor (Y, Gd)BO3:Eu3+ with grain shape, small size, non-agglomerate, high crystallinity and good photoluminescence (PL) intensity was prepared by a complex method that the precursor of the phosphor was prepared by co-precipitation method and the phosphor was prepared by combustion method. The SEM photos and the photoluminescence spectrum excited under VUV show that the morphology and luminescent properties of this phosphor are satisfied when an appropriate amount of urea was adopted as the combustion agent in the preparation procedure.     

应用加权最小二乘法辨识水下推进电机参数

建立数学模型，采用ＭＣＳ－５１系列单片机数据采集系统记录电枢绕组中电流变化过程以及电机的转角速度．应用加权最小二乘的系统辨识法对永磁直流伺服电动机的参数测定进行了探讨，并编制了这种电机参数变识的计算机程序．所得结果经计算机仿真验证，其暂态过程与实测过程比较吻合，证明了该方法的可行性．     

信息时代的全球制造策略--兼议我国制造业的发展

根据当前国际制造业的发展和因特网的广泛应用，论述发展全球制造的必然趋势，讨论全球制造企业发展的条件和方式，提出我国机械制造业应如何在竞争中求生存的建议，并着重阐述开发应用CAD系统、建立企业信息管理系统的重要性，以及提出在产品设计和制造过程中的创新是企业在市场竞争中取得成功和创建全球化制造企业的必要条件。     

TA1板材对角拉伸试验及数值模拟研究

为了测试钛合金材料的抗皱性能,以及验证塑性成形仿真软件对起皱问题的预测精度,选取了钛合金TA1材料进行方板对角拉伸试验,同时对试验过程进行数值模拟分析,对比试验结果和模拟结果,验证了数值模拟的准确性。在方板对角拉伸试验的数值模拟过程中,通过设置不同的扰动类型来替代外界影响因素,以及不同的单元阶次、算法等模拟参数,来分析各类模拟参数对数值模拟结果的影响规律。结果表明,不同的扰动类型对模拟结果产生的影响很小,采用二次单元和静态算法的数值模拟结果与试验结果基本一致,因此能够有效预测由不均匀拉应力引起的板材起皱现象。     

La基高k栅介质的研究进展

SiO2作为栅介质已无法满足MOSFET器件高集成度的需求,高k栅介质材料成为当前研究的热点。综述了高k栅介质材料应当满足的各项性能指标和研究意义,总结了La基高k栅介质材料的最新研究进展,以及在改正自身缺点时使用的一些实验方法,指出了有可能成为下一代MOSFET栅介质的几种La基高k材料。La基高k材料的研究为替代SiO2的芯片制造工艺提供优异的候选材料及理论指导,这是一项当务之急且浩大的工程。     

Optical and electrical characterization of GaAs-based high-speed and high-sensitivity delta-doped resonant cavity-enhanced HMSM photodetector

We have previously reported an AlGaAs-GaAs-based delta modulation doped resonant cavity-enhanced, heterostructure metal-semiconductor-metal (HMSM) photodetector design with wavelength selectivity, high sensitivity, and high-speed properties. In this paper, the influences of the resonant cavity and the delta modulation-doped layer on the optical and electrical performances of HMSM photodetectors have been studied by using the transmission line model and Ramo's theorem, respectively. The microcavity offers narrow spectral bandwidth detection accompanied by a drastic increase of the optical field at the resonant wavelength, solving the tradeoff between high efficiency and high speed with the thinner absorption regions. The top AlGaAs delta modulation-doped layer presents an enhanced barrier height associated with the vertically oriented two-dimensional potential and field profiles rather than the horizontally oriented ones, providing very low dark current values and an increase in device responsivity and speed of the response. Optimizing the optical and electric field simultaneously results in high-performance photodetection without further scaling down the devices. Two separate groups of photodetectors with various geometries have been fabricated, characterized, and simulated: One with a delta modulation-doped structure, the other without this doped layer. Delta-doped photodetectors show wavelength selectivity at 850 nm with about a 30-nm full width at half-maximum (FWHM), 9.2 fA//spl mu/m/sup 2/ dark current, less than 30 fF capacitance, 10.6-ps FWHM, and 18.4-ps fall time. Photocurrent spectral response, dark current, time response, and capacitance-voltage measurements consistently show that the delta-doped detectors have the better optical and electrical performances over the undoped ones.     

四川白玉铜铅锌共生矿清洁分离技术研究

四川白玉铜铅锌共生矿矿石性质复杂,铜铅矿物嵌布粒度极细,铜锌矿物致密共生,分离较为困难。采用铜铅部分混合优先浮选-选铅-选锌-铜铅混合精矿加压浸出分离工艺流程,以EM-WB-12为铜矿物捕收剂进行选矿试验,并在选铅时进行了粗精矿再磨,实验室试验可获得Cu+Pb品位28.09%,铜、铅回收率分别为85.00%、53.38%的铜铅混合精矿,铅品位和回收率分别为52.68%、30.13%的铅精矿以及锌品位和回收率分别为52.72%、73.62%的锌精矿,同时伴生银得到了有效回收。对铜铅混合精矿进行加压浸出,取得了Zn浸出率94.36%,Cu浸出率91.21%的优良指标,渣中Pb脱硫后品位达到40%。在此基础上进行了选矿扩大试验,其试验指标较好地验证了实验室试验结果。     

Behavioral patterns of drop impingement onto rigid substrates with a wide range of wettability and different surface temperatures

This article concerns behavioral patterns of droplet impingement onto solid substrates covering a wide range of wettability from hydrophilic to superhydrophobic surfaces heated at different temperatures. For droplet impingement onto partial hydrophobic surfaces (mirror‐polished Cu substrate), the maximum heights of receding droplet undergoing a consecutive increment with surface temperature can be explained taking account of Marangoni flow. Also, the relation to predict the increment of droplet heights with surface temperature was manifested in the light of lubrication approximation combined with energy conservation. However, this relation is only valid for droplet impacts onto partial hydrophobic surface, because the recoiling droplet height was observed to be independent of surface temperature for both hydrophilic and superhydrophobic targets. This phenomenon was attributed to inherent wettability accompanying larger contact angle hysteresis for the hydrophilic substrate and to the presence of an adiabatic gas layer between the composite surface and impacting droplet, for the superhydrophobic target. © 2009 American Institute of Chemical Engineers AIChE J, 2009