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81.
LiFePO4 is a potential candidate for the cathode material of the lithium secondary batteries. A co-precipitation method was adopted to prepare LiFePO4 because it is simple and cheap. Nitrogen gas was needed to prevent oxidation of Fe2+ in the aqueous solution. The co-precipitated precursor shows the high reactivity with the reductive gas, and the single phase of LiFePO4 is successfully synthesized with the aid of carbon under less reductive conditions. LiFePO4 fine powder prepared by co-precipitation method shows high rate capability, impressive specific capacity and cycle property. 相似文献
82.
Human facial gestures often exhibit such natural stochastic variations as how often the eyes blink, how often the eyebrows and the nose twitch, and how the head moves while speaking. The stochastic movements of facial features are key ingredients for generating convincing facial expressions. Although such small variations have been simulated using noise functions in many graphics applications, modulating noise functions to match natural variations induced from the affective states and the personality of characters is difficult and not intuitive. We present a technique for generating subtle expressive facial gestures (facial expressions and head motion) semi‐automatically from motion capture data. Our approach is based on Markov random fields that are simulated in two levels. In the lower level, the coordinated movements of facial features are captured, parameterized, and transferred to synthetic faces using basis shapes. The upper level represents independent stochastic behavior of facial features. The experimental results show that our system generates expressive facial gestures synchronized with input speech. 相似文献
83.
基于网络环境的计算机资料室工作 总被引:1,自引:0,他引:1
随着信息技术的迅速发展,基于网络的信息资源共享已成为信息化社会的基本特征。数字化图书馆和电子期刊网的出现,正在改变着人们的阅读习惯,丰富的信息资源和跨时空的浏览方式彻底颠覆了传统的图书馆、资料室的服务模式。同时,数字化图书馆也给资料室管理模式创新带来了新的契机。分析了院系资料室面临的挑战与机遇,探讨了新形势下计算机资料室工作,提出了利用信息技术,改革服务方式,拓展服务内容,提高服务水平,提供有特色的专业服务。 相似文献
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F Javier Benítez Ana I Leal Francisco J Real Juan L Acero Gloria Roldán 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(3):309-316
BACKGROUND: The first stage of the cork industrial process generates great volumes of wastewater with moderate to high organic pollutant content that must be purified using different procedures, such as filtration by membranes. RESULTS: The tangential filtration of these wastewaters was studied using two different laboratory equipments. In the first one, three ultrafiltration (UF) membranes were tested, with molecular weight cut‐off (MWCO) 100 kDa and 30 kDa, and two operating modes were used: total recycling of permeate and retentate streams, and in continuous mode, without recycling both streams. In the total recycling UF experiments, the influence of the operating variables on the permeate flux was first established. The effectiveness of the different membranes was determined by evaluating the rejection coefficients for several parameters that measure the global pollutant content of the effluent. The values found for these rejection coefficients were in the following order: ellagic acid and color > absorbance at 254 nm > tannic content > COD (chemical oxygen demand). In the continuous mode experiments, the fouling mechanism for each membrane was established by fitting the experimental data to various filtration fouling models given in the literature. The operating mode in the second equipment was batch concentration, and additional experiments were carried out with an UF membrane (2 kDa), and with a NF membrane (with MWCO in the range 150–300 Da). CONCLUSIONS: The three operating modes tested provided different rejection levels of organic matter; among them, the most effective procedure tested was batch concentration mode using a NF membrane. Copyright © 2007 Society of Chemical Industry 相似文献
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VPN技术在企业中的应用 总被引:2,自引:0,他引:2
阐述了VPN的概念、特点,提出了VPN技术在企业中的一些应用方法,并给出了具体创建、实现过程。 相似文献
90.
提出了基于压电技术的微操作系统的自动标定方法,采用混合式步进电机直接驱动的宏动平台,实现系统大行程宏动定位,安装在宏动平台上的压电陶瓷驱动的微动平台和精密光栅,实现亚微米级的分辨率和定位精度,通过以上两部分实现定位机构的全闭环反馈控制,采用显微视觉反馈获取微动台操作器在图像中的位置信息进行标定。实验结果表明:系统的动态和稳定性能良好,自动标定运算速度快,运行速度达到11 frame/s,实现了对系统的精确标定,标定精度达到0.1μm。 相似文献