基于双延迟工作台的泵浦-探测光测量技术的改进

为了提高飞秒激光瞬态热反射测量技术的测量精度并增加测试的可靠性,延长了泵浦光和探测光的相对光程差,以提高实验数据与理论模型间的拟合精度．通过在泵浦光路中放置一个和探测光路中同样的机械位移平台,搭建了一个新的测试实验台,将两光束的光程差由4ns提高到8ns．测量结果表明,当后4ns的测量数据与前4ns的数据平滑连接后,泵浦光和探测光束间由于发散和飘移所引起的测量误差可忽略不计．对Al／Si和Cr／Si样品界面热导的测量结果表明,实验测得值和现有文献报道数据非常吻合,证实了改进系统的可靠性．     

电导法测定弱电解质醋酸的电离平衡常数

采用DDS— 12A型电导率仪和HS— 4精密恒温浴槽 ,用电导法测定了 2 5℃条件下弱电解质醋酸的电离平衡常数Kc为 1.6 6× 10 -5,与理论值 1.75× 10 -5相比 ,略为偏小 ,可能是系统误差造成的     

电解质稀溶液电导的预测方法

根据Debye-Hueckel理论和Onsager理论，发展了一种强电解质稀溶液电导的预测方法，该方法适宜用于极限摩尔电导已知或未知的条件下电解质溶液摩尔电导的计算。对大量电解质溶液的计算结果表明，电导预测值与实验值的一致性令人满意，平均误差1．32％。     

Transmission Modulated by QuantumGatein AharonovCasher Ring

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Verification of the stomatal conductance of Nebbiolo grapevine

Wine is one of the most important Italian export products, and Nebbiolo is one of the most respected Italian grapes. In the summer of 2007, a measurement campaign was carried out in a Nebbiolo vineyard located in Vezza d＇Alba, near Cuneo, Italy. Using a gauge of trade gases and some other instruments, we recorded the stomatal conductance and also some physiological parameters useful for estimating the dependence of stomatal conductance on environmental variables. The goal of this experiment was improving the parameterization of grapevine evapotranspiration through the assessment of the stomatal conductance and, in particular, of the functional dependence of the stomatal conductance on the following variables： the photosynthetically active radiation, the atmospheric temperature, the atmospheric moisture deficit, and the carbon dioxide concentration. The observations allowed us to check and, in some cases, to adapt the existing general parameterizations found in literature. The results showed some significant differences with the existing parameterizations concerning the atmospheric temperature, the atmospheric moisture deficit, and the carbon dioxide concentration. The parameterizations obtained in this experiment, although referring to a specific plant and site （namely the Nebbiolo at Vezza d＇Alba）, could allow assessment of the best environmental conditions under which the Nebbiolo grapevine production is the best, and in future could be tested for other grapevines or climates.     

TiO2掺杂Ag/SnO2电接触材料物理性能的研究

采用机械混合法、溶胶-凝胶法制备TiO2掺杂Ag/SnO2电接触材料。实验结果表明,在机械混合法中,Ti4 不能进入SnO2的晶格,也没有提高SnO2的电导率;在溶胶-凝胶法中,Ti4 能够很好地进入SnO2的晶格,从而改善触头的电性能。微观组织分析表明:纳米触头中SnO2的分布要比非纳米触头中SnO2分布均匀,可以避免因SnO2的富集而降低电导率,从而提高Ag/SnO2触头的电性能和电寿命。     

弱电解质溶液无限稀时的摩尔电导测定

通常认为 ,弱电解质溶液无限稀时的摩尔电导Λ0 不能直接测定 ,它只能通过相关强电解质溶液无限稀时的摩尔电导及离子独立移动定律计算得出 .事实上 ,通过弱电解质溶液的电导率测定 ,不仅可以确定弱电解质的电离平衡常数 ,而且可以确定弱电解质无限稀时的摩尔电导 .与此同时 ,也发现了弱电解质溶液的浓度与其电导率之间的关系方程     

通过带有量子门的Aharonov-Casher环的自旋极化电导振荡

1 Introduction Since some experi ments made by Yacoby,et al.[1],and Schuster ,et al.[2],that first measured electrontransmission phase through a quantum dot ( QD) ,phase sensitive transports in open mesoscopic ringwith a QD have been extensively investiga…     

关于磁水性质的实验研究

水在磁场中流动或静止处理，其理化性质都会发生变化，但２种处理方式生产的磁水性质有显著差异．磁水的表面张力系数随磁处理时间的延长先增大、再减小、再增大，煮沸后冷却不影响磁水效应     

基于区域的四阶偏微分方程去噪方法

由于四阶偏微分方程的图像去噪方法在有效降噪的同时能很好地保持特征并避免二阶偏微分方程处理图像常出现的块状效应,提出了一种基于区域的四阶偏微分方程的图像去噪方法.首先,该方法根据斑点噪声在拉普拉斯域中所具有的统计特性,将图像区域分为斑点区域和非斑点区域;然后,针对不同的区域采用不同的传导系数.此外,采用频域法来确定迭代停...