Effects of clouds, sea surface temperature, and its diurnal variation on precipitation efficiency

The effects of clouds, sea surface temperature, and its diurnal variation on precipitation efficiency are investigated using grid-scale data from nine equilibrium sensitivity cloud-resolving model experiments driven without large-scale vertical velocity. The precipitation efficiencies are respectively defined in surface rainfall, cloud, and rain microphysical budgets. We mathematically and physically demonstrate the relationship between these precipitation efficiencies. The 2℃ increases in spatiotemporal invariant sea surface temperature (SST) from 27℃ to 29℃ and from 29℃ to 31℃, and the inclusion of diurnal SST difference 1℃ and the 1℃ increase in diurnal SST difference generate opposite changes in the precipitation efficiency by changing ice cloud-radiation interactions. The radiative and microphysical processes of ice clouds have opposite effects on the precipitation efficiency because of the rainfall increase associated with the reduction in the saturation mixing ratio caused by the exclusion of radiative effects and the decrease in rainfall related to the reduction in net condensation caused by the exclusion of deposition processes. The radiative effects of water clouds on the precipitation efficiency are statistically insensitive to the radiative effects of ice clouds.     

Experimental Verification of Left-Handed Metamaterials Composed of Coplanar Electric and Magnetic Resonators

We verified experimentally left-handed metamaterials （LHM） composed of coplanar electric and magnetic resonators. A typical LHM sample composed of coplanar resonator unit cells was fabricated, investigated and tested. The experimental results show that the tested sample has a left-handed band of width 1.4 GHz in the X band. The experimental results agree quite well with the simulation ones. Moreover, both the simulation and experimental results show that the LHM under study can automatically achieve good impedance-matching in the left-handed band.     

软件实验环境的建立

下面介绍怎样建立软件实验环境，即安装Microchip公司提供的MPLAB开发工具和HITECH公司提供的C编译器。     

数字显示恒流型电子负载机

笔者是从事铅酸电池充电器产品的设计工作的，通常充电器量产后，在出厂时需要进行4～8小时的满载老化实验，以确保产品质量稳定。最初，我们的做法是用实际的铅酸电池进行老化实验，但当出货量大时，需要购买很多颗电池才能满足出货量的要求，这给资金与仓库管理都带来了很大的压力。后来，我们采用大功率电阻来老化电源，     

DIS实验在初中物理教学中的应用初探

尝试将DIS实验引入初中物理课堂,发现初中物理的部分力学、热学、电学实验也可以使用传感器来做,且相对传统实验具有以下一些优点.     

MIT在线实验室

1998年，电子工程学教授热苏斯-德尔·阿拉莫（Jesdsdel Alamo）正在讲授晶体管物理学这门课，而授课过程曾让他倍感沮丧。“我那时教的学生中有大学生，也有研究生，但是他们都接触不到任何实验仪器。”阿拉莫说。“我认为让学生们有机会做实验非常重要，他们需要在简单电路上测试晶体管的特性，评估有多少在课堂上学到的东西能在实验室中真实地感触到。”     

警惕物理实验教育的零功能和负功能

指出了物理实验教育不仅具有正功能,也会出现零功能和负功能,分析了零功能和负功能的表现及其成因,并据此提出了相应的措施.     

一道习题的价值探究

题目已知a〉0，b〉0，求证： （a＋b）（1/a＋1/b）≥4 ① 这是高中数学实验课本北师大版（选修4—5）练习2第1题，此题看似平淡，但内涵丰富，对它进一步探究，可达到培养思维、提高能力之效．     

东南大学物理系南京培中科技开发研究所

计算机应用于物理实验，这是大学物理实验的基本要求之一。目的有三：①加速实验室的现代化建设；②学习计算机在实验中的应用：③在有限的实验时间内，加速对实验数据的采样、计算、作图等。腾出时间，加深对实验内容的探索。如果安排得当，一台计算机可为四个左右实验服务。