超导薄膜表面电阻测试方法及误差分析

本文介绍一种蓝宝石加载单端短路谐振腔测量高温超导薄膜的方法，并对测量误差进行了较详细的分析．造成测量误差的主要因素有三个：系统无载品质因数Q0的测量误差，超导薄膜以外损耗品质因数Qother的实验误差，以及在谐振腔内超导薄膜的几何参数G的计算误差．大量的实验结果表明，本方法操作简便，重复性好，测量精度高，相对测量误差不超过10％．     

Synthesis of Boron-Rich Cubic B（CxN1-x） Compounds

B2CN precursor is prepared by a mechanical vibration-milling process using amorphous boron, graphite and h-BN powders with mole ratio of 1：1：1. A mixture of precursor and Ca3B2N4 catalyst is treated under high pressure and high temperature. A boron rich cubic B（CxN1-x） phase is obtained after removing the catalyst by acid treatment. The average C content of the boron-rich cubic phase is about 6 at.% detected by energy-dispersive x-ray analysis spectroscopy. It is found that the highest carbon content in the cubic phase is as large as 16 at.%.     

Gumbel分布最大吸引场的次序统计量的精致渐近性

得到一类Gumbel分布最大吸引场的随机容量样本的次序统计量的精致渐近性,揭示了收敛速度、权函数、边界函数及极限状态之间的联系.这类吸引场真包含了全体(γ),γ>0分布族.     

水分对锂离子电池性能的影响

水分对锂离子电池性能的影响;锂离子电池;电池电化学性能;SEI膜     

Icephobic performance on the aluminum foil-based micro-/nanostructured surface

The research of superhydrophobic materials has attracted many researchers' attention due to its application value and prospects.In order to expand the serviceable range,people have investigated various superhydrophobic materials.The simple and easy preparation method has become the focus for superhydrophobic materials.In this paper,we present a program for preparing a rough surface on an aluminum foil,which possesses excellent hydrophobic properties after the treatment with low surface energy materials at high vacuum.The resulting contact angle is larger than 160° and the droplet cannot freeze on the surface above-10 ℃.Meanwhile,the modified aluminum foil with the thickness of less than 100 μm can be used as an ideal flexible applied material for superhydrophobicity/anti-icing.     

“借东风”妙解三角题

诸葛亮认真分析敌我战势及天气变化情况,巧借东风,大败敌军．此故事常激发我的灵感,在解三角题中认真分析题目,适时巧借,常可绽放解题奇花,令人回味无穷!兹举两例,以飨读者．     

ISOLATION AND CHARACTERIZATION OF THE SPECIFIC PEPTIDES FROM RABBIT BLASTOCYST AT PERI-IMPLANTATION STAGE WITH EMPHASIS ON THEIR PHYSIOLOGICAL SIGNIFICANCE RELEVANT TO THE MECHANISM OF IMPLANTATION

The secrctory materials from the uterine flushings of the pregnant, non-pregnant and pseudopreg-nant rabbits were analysed by the method of SDS-polyacrylamide gel electrophoresis. The results demon-strated that there are three specific peptides in the pregnant uterine flushings with molecular weightsof 3000, 4500 and 6000. No correspondent peptides were found in non-pregnant and pseudopregnantuterine flushings. The peptides were also isolated and identified from the blastocystic fluid. At least 4peaks of small peptides were shown by high pressure liquid chromatography. The range of their isoelec-trophoretic points is between pH 4.0-5.5 Concavalin A (Con A) affinitive electrophoresis indicated thatthey are glycopeptides in nature. The LH-RH A is able to exert inhibitory effects on the synthesis ofthese peptides. Their possible physiological function has been discussed.     

长颈管在微型脉冲管制冷机中的应用分析

长径管作为调相器应用于微型脉冲管制冷机系统时存在阻抗不匹配现象,即调相效果好时,往往脉冲管热端阻抗大小,从而使脉冲管中的压力波幅值小,蓄冷器中损失增大,制冷性能降低;用不同管径和长度的长径管作为调相器时,最低制冷温度产生在阻抗匹配区域或热端阻抗最大的区域;对于本实验中的微型脉冲管制冷机,以长颈管作为调相器时最低制冷温度为107.3 K,低于以单纯的小孔阀作为调相器时所获得的最低制冷温度,但还达不到双向进气的水平。     

概率论教学中值得注意的几个问题

<正> 概率论是中专学校唯一的一门研究随机现象统计规律的数学课程。由于随机现象的不确定性,使得学生在学习概率论的过程中,往往感到对某些概念、公式理解不透,从而解题时就不那么得心应手。本文是自己在概率论教学中的一点体会。