热红外遥感中大气透过率的研究(二): 大气透过率模式的应用

大气透过率是热红外遥感中的一个重要参数。针对前文构建的大气透过率模式, 以我国环境灾害卫星HJ-1B红外相机IRS第4通道的大气透过率模式为例, 利用辐射传输模型MODTRAN模拟水体辐亮度, 对模式中的变量引入不同的误差, 将模拟的辐亮度反演水温, 分析不同气溶胶模型、水汽量、能见度和观测天顶角对反演水温的敏感性。并将该大气透过率模式用于HJ-1B/IRS热红外图像中, 反演了2009年4月17日、21日、22日和25日太湖水温。研究结果表明: 同一波段、不同气溶胶模型的大气透过率模式在反演温度时会产生不同的误差, 以气溶胶模型为平流雾的最大、对流型的最小;大气透过率模式中3个变量的误差与温度反演的误差呈线性关系, 即变量的误差越大, 温度反演的误差也越大;以水汽量对温度反演最敏感, 观测天顶角其次, 能见度最弱。该大气透过率模式用于4天遥感图像反演中, 除4月17日反演的误差稍高, 均方根误差和平均相对误差分别为1.127 ℃和5.75%, 其他3天的均方根误差都小于1 ℃、平均相对误差在5%以下, 说明所建的大气透过率模式在热红外遥感中具有较高的应用精度。     

英巴卡迪诺:优化数据库性能,扩展IT基础架构

随着企业的业务发展,将会有更多的应用系统增加到企业的业务系统基础架构中来.企业的各种系统随着业务扩大和信息化程度加深而不断发展,而且这些系统和应用大多是以数据为中心,都将导致业务系统基础架构的数据量激增和复杂度加大.     

ILM在at&t的应用

at&t的统一数据库平台解决方案让其IT工作人员能够同步管理多个Oracle数据库或其他主流数据库,并能轻松地将数据库架构整合在一起.     

From Discreteness to Continuity： Dislocation Equation for Two-Dimensional Triangular Lattice

A systematic method from the discreteness to the continuity is presented for the dislocation equation of the triangular lattice. A modification of the Peierls equation has been derived strictly. The modified equation includes the higher order corrections of the discrete effect which are important for the core structure of dislocation. It is observed that the modified equation possesses a universal form which is model-independent except the factors. The factors, which depend on the detail of the model, are related to the derivatives of the kernel at its zero point in the wave-vector space. The results open a way to deal with the complicated models because what one needs to do is to investigate the behaviour near the zero point of the kernel in the wave-vector space instead of calculating the kernel completely.     

盘活企业资金 服务通信建设——谈谈辩证法在资金运行中的应用

运用辩证法盘活企业资金,正确处理各种关系,从而有限的资金发挥了最大的作用..     

电荷屏蔽对快中子俘获过程的影响

本文计算在初生中子星中微子驱动的星风环境中弱电荷屏蔽对质子电子俘获反应的影响.结果表明电荷屏蔽对星风中核子的比加热率、熵等物理参量基本没有影响.但是可以明显提高电子丰度,而这种提高有力地支持了最新的快中子俘获核合成结果.     

英巴卡迪诺：优化数据库性能，扩展IT基础燃

随着企业的业务发展,将会有更多的应用系统增加到企业的业务系统基础架构中来。企业的各种系统随着业务扩大和信息化程度加深而不断发展,而且这些系统和应用大多是以数据为中心,都将导致业务系统基础架构的数据量激增和复杂度加大。企业的IT部门面临前所未有的复杂性挑战,需要确保业务系统的可用性、高性能、可靠性、可扩充性,提高IT服务质量。     

锯齿型单壁碳纳米管的广义层错能计算

基于密度泛函理论的第一性原理方法,计算了两种不同半径的锯齿型单壁碳纳米管以及单层石墨的广义层错能曲线。对小位移处广义层错能曲线进行斜率拟合所得切变模量与其它文献值一致。对三条广义层错能曲线的对比可知,锯齿型碳纳米管与单层石墨的广义层错能曲线相近,锯齿型单壁碳纳米管的曲率效应不明显。     

On the core structure and mobility of the 〈100〉{010} and 〈100〉{01^-1} dislocations in B2 structure YAg and YCu

Dislocations are thought to be the principal mechanism of high ductility of the novel B2 structure intermetallic compounds YAg and YCu.In this paper,the edge dislocation core structures of two primary slip systems 〈100 〉{010} and 〈100 〉 {011} for YAg and YCu are presented theoretically within the lattice theory of dislocation.The governing dislocation equation is a nonlinear integro-differential equation and the variational method is applied to solve the equation.Peierls stresses for 〈100 〉 {010} and 〈100 〉 {011} slip systems are calculated taking into consideration the contribution of the elastic strain energy.The core width and Peierls stress of a typical transition-metal aluminide NiAl is also reported for the purpose of verification and comparison.The Peierls stress of NiAl obtained here is in agreement with numerical results,which verifies the correctness of the results obtained for YAg and YCu.Peierls stresses of the 〈100 〉 {011} slip system are smaller than those of〈100 〉 {010} for the same intermetallic compounds originating from the smaller unstable stacking fault energy.The obvious high unstable stacking fault energy of NiAl results in a larger Peierls stress than those of YAg and YCu although they have the same B2 structure.The results show that the core structure and Peierls stress depend monotonically on the unstable stacking fault energy.     

Dislocation energy and calculation from Peierls stress： a rigorous the lattice theory

In the classical Peierls--Nabarro (P-N) theory of dislocation, there is a long-standing contradiction that the stable configuration of dislocation has maximum energy rather than minimum energy. In this paper, the dislocation energy is calculated rigorously in the context of the full lattice theory. It is found that besides the misfit energy considered in the classical P-N theory, there is an extra elastic strain energy that is also associated with the discreteness of lattice. The contradiction can be automatically removed provided that the elastic strain energy associated with the discreteness is taken into account. This elastic strain energy is very important because its magnitude is larger than the misfit energy, its sign is opposite to the misfit energy. Since the elastic strain energy and misfit energy associated with discreteness cancel each other, and the width of dislocation becomes wide in the lattice theory, the Peierls energy, which measures the height of the effective potential barrier, becomes much smaller than that given in the classical P-N theory. The results calculated here agree with experimental data. Furthermore, based on the results obtained, a useful formula of the Peierls stress is proposed to fully include the discreteness effects.