我的MySpaceIM我做主

相信朋友们对于MySpace(http://myspace.cn)并不陌生,它是一个全球性的娱乐社区,我们可以在上面广交朋友,写博客日志,发布公告,策划活动等等,面对一个这么大的网络大社区,如何来快速实时地与好友进行联络沟通呢?借助于MySpace的IM即时聊天软件就能轻松实现。     

只聊QQ非诚勿扰

用QQ聊天交流非常方便。但它也有闹心的时候：安装时捆绑的各种附加功能对某些人并不实用．而且聊天窗口还会夹杂广告，这对于仅仅想用它聊天交流的人就多余了，既然不能忍，就只有自己动手将这些烦恼“拒之门外”。本文以最新版的QQ 2009 beta2为例来说明，同样适用于QQ 2008的版本。     

电脑上过把DJ瘾

听惯了的老歌，如果改变一下它的节拍，一曲抒情歌曲没准就会变成澎湃激昂的摇滚乐，在现实生活中可以玩这种音乐魔法的人我们称之为DJ。虽然DJ那昂贵的调音台可不是每个人都有机会触碰的，     

用“剩余物资”造本本散热桌

经过一次装修．家中或多或少都会剩下一些装修材料。它们虽然形同鸡肋，但直接扔掉未免太过可惜。既然是一名Geek，那么就应该利用这些“剩余物质”敲打出一点东西来。比如下面介绍的本本散热桌。虽然看外观它也许不如许多成品本本桌，但除了成本低廉之外，它还拥有出色的散热性能哟!既然能够自己做，那么何必费力去电脑城看着JS（奸商）的脸色杀价呢？下面，我们就把本本散热桌的诞生史和盘托出。     

Microwave imaging using the finite-element method and a sensitivity analysis approach

A method for reconstructing the constitutive parameters of two-dimensional (2-D) penetrable scatterers from scattered field measurements is presented. This method is based on the differential formulation of the forward scattering problem, which is solved by applying the finite-element method (FEM). Given a set of scattered field measurements, the objective is to minimize a cost function which consists of two terms. The first is the standard error term, which is related to the measurements and their estimates, while the second term, which is related to the Tikhonov regularization, is used to heal the ill posedness of the inverse problem. The iterative Polak-Ribière nonlinear conjugate gradient algorithm is applied to the minimization of the cost function. During each iteration of the algorithm, the direction of correction is computed by using a sensitivity analysis approach, which is carried out by an elaborate finite-element scheme. The adoption of the finite-element method results in sparse systems of equations, while the computational burden is further reduced by applying the adjoint state vector methodology. Finally, a microwave medical imaging application, which is related to the detection of proliferated bone marrow, is examined, while the robustness of the proposed technique in the presence of noise and for different regularization levels is investigated.     

Single-mode, singly resonant, pulsed periodically poled lithium niobate optical parametric oscillator

We report single longitudinal mode operation of a pulsed Nd:YAG pumped periodically poled lithium niobate optical parametric oscillator (OPO). The combination of a prism and an etalon provides both coarse and fine spectral resolution, thereby eliminating parasitic resonant oscillation of cascaded signal wavelengths, idler wavelengths, and adjacent longitudinal modes of the signal field. Optical bandwidths of less than 300 MHz have been obtained at signal wavelengths between 1.47 and 1.59 mum. In comparison with broadband operation, the single-mode OPO shows only a 9% reduction in pump depletion with a negligible reduction in extraction efficiency.     

既美观又实用 为墙纸添加漂亮日历

电脑或是PSP、iPhone上都可以用到各种漂亮的墙纸,我们会经常更换,以此获得更好的心情。那么,有没有想过为这些墙纸添加实用的日历功能呢？这样一来,墙纸既能养眼美观,也能直观地看到日历,便于自己安排工作或其他事务。尽管在电脑上可以借助于各类记事日历软件来实现这种功能,但要额外安装软件,比较麻烦。其实,可以直接在线制作一张包含日历的墙纸。     

利用GoogleEarth查看城市的变迁

相信很多朋友都曾听说过Google Earth的大名,目前Google发布了这个软件的5．0测试版本,借助这个版本查看地球某一区域的历史,例如看一看自己城市几十年间的变化,是不是很有趣？     

淘宝购物 包打听

网上购物的便利是毋容置疑的,但有一点是不能回避的,你不能像去商场、超市那样见到实物进行验证,而网上购物通常只能借助于卖家提供的图片和宝贝描述,以及买家对卖家的评价等来决定是否购买。其实不妨先听听别人