纳米镍粉体的晶格膨胀

采用阳极弧放电等离子体技术成功制备了各种不同晶粒尺寸的纳米镍粉体材料，并利用X射线衍射(XRD)、透射电子显微镜(TEM)和相应选区电子衍射(SAED)等测试手段对所制备的样品的晶体结构、晶格参数、形貌、粒度进行性能表征. 实验结果表明：阳极弧等离子体法制备的镍纳米粉的晶体结构与相应的块物质相同，为fcc结构的晶态. 不同晶粒尺寸的纳米镍粉体的晶格常数均大于完整单晶镍的晶格常数，晶格畸变表现为晶格膨胀. 晶格常数和晶胞体积随着晶粒尺寸的减小而增大，晶格畸变量与晶粒尺寸的倒数成正比. 镍纳米粉体的晶格膨胀主要是由于受到表面能和表面张力的作用而引起的，可以利用纳米晶体的热力学理论作定性解释. 关键词： 镍纳米粉体 晶格常数 晶格膨胀 晶胞体积     

金团簇掺杂镍原子的量子化学研究

利用基于密度泛函理论的量子化学从头计算方法,计算了金掺杂镍原子团簇AunNi2(n=1~4)的稳定结构和对应的电子态,部分稳定结构具有较高的自旋多重性.比较研究AunNi2和Aun的稳定性,结果表明Au-Ni相互作用较强,掺入两个Ni原子提高了纯金团簇的稳定性,而且团簇体积越大,这种影响越小,计算结果还再现了封闭结构高稳定性质的振荡性.     

Determination of Thermal Conductivity of Liquids by a Multi-Point Laser Pump Method

As an advanced optical method, a multi-point pump method is presented for measurements of thermo-physical properties of liquids. Meanwhile, based on the laser-induced thermal grating method, a new theory model is presented and used to analyse the thermal effects caused by the multi-point laser pump, by which the thermal conductivity of liquids can be obtained. The results of some typical liquids, such as water, ethanol and acetone, are presented and are consistent with those of acknowledged values, demonstrating that the multi-point method is simple and useful for characterizing thermal properties of liquids.     

绕Hydronautics水翼空化云流动的实验研究

采用高速全流场显示技术和DPIV对空化水翼近壁处的空化云流动形态和运动机理进行了讨论.结果表明:绕Hydronautics翼型的空化云运动是一个准周期性过程:稳定空泡团初生在翼型前部,向翼型后部发展布满整个翼面,在翼型后缘出现汽泡团旋涡,伴随反向运动,最终向下游脱落.当前条件下空泡团旋涡脱落周期约为74 ms.空化区与主流区的交界面上存在较大的速度梯度,一组对涡出现在翼型尾部处交界面上.此外,采用以空泡为示踪粒子的DPIV能够对空化流动流速分布进行有效测量.     

设计性实验与应用结合的尝试

以应用型设计性实验 《教室的采光及照度的综合评价》为例， 阐述了教改新的设计思想， 并分析总结实施所取得的成果     

并行算法到并行结构的映射

本文以“匹配”法为基础，给出了新的目标函数，并以此设计映射算法，最后给出试验结果。     

A NUMERICAL METHOD FOR OPTIMAL INPUT DESIGN BY FREQUENCY DOMAIN CRITERIA

(1) Introduction Most of the existing literature on input design for identification has been concentrated on the problem of obtaining accurate parameter estimates. Many of them discussed how to determine optimal inputs which minimize a scalar valued function of the inverse Fisher information matrix.The minimization has been performed under certain constraints to prevent the diverge of the input or output amplitude.     

EFFECT OF SIMULATED WEIGHTLESSNESS ON THE RESPONSE CHARACTERISTICS OF HUMAN BRAIN

In order to systematically investigate the effects of simulated weightlessness on thefunction state of human brain, 15° head-down tilt (HDT) was used to simulate weightless-ness, and the response changes of event-related EEG power spectra, medium-frequencysynchronous potentials and slow-waves were examined in the present study. It was foundthat HDT had characteristic effects on the above EEG responses, suggesting that the ef-fects mainly occurred in the brain's regulatory system, therefore, resulting in changes ofthe brain function state.     

核计算技术在核测井中的应用

本文介绍了核计算技术在核测井中的应用概况及其具体应用实例。     

含硫配体在ZnS：Cu水溶胶制备中的应用

体相ＺｎＳＣｕ具有优越的交直流电致发光性能，在屏幕显示领域有着广泛的应用［１］．近年来随着ＺｎＳＭｎ纳米材料研究的深入［２～４］，对于纳米ＺｎＳＣｕ的研究也引起了人们极大的兴趣［５］．但研究进展十分缓慢，主要原因一是由于其中的掺杂元素以Ｃｕ（Ⅰ）的形...