边缘简支30°-60°-90°三角板的平衡、稳定与振动问题

一.引言 三角形薄板问题已经解决的不多。在边缘简支的情形,截至目前为止,只解决了等腰直角三角板和等边三角板的问题。至于30°—60°—90°三角板的问题,据作者所知,还没有人讨论过。过去研究过简支等腰直角三角板弯曲问题和稳定问题的作者有:伽遼金,纳达埃和赛斯。过去研究过等边三角板弯曲问题和稳定问题的作者有:马科斯,富诺斯基-克里格,孙,赛斯和斯蒂芬生。斯蒂芬生的结果是包含在他用复变函数研究厚板平衡问题的解答中,最近在尚尼津的专著中,也载有简支等边三角板稳定问题的解答。孙,雪弗尔和哈佛斯等作者都研     

360°彩虹全息术

３６０°彩虹全息术周其麟，李智祥，周淑琴（武汉工业大学４３００７０）一、前言大于１８０°的宽视场柱形全息图在本世纪７０年代就已制出，但必须用窄带光源照明，才能获得今人满意的三维全息像１９７７，Ｌ．Ｃｒｏｓｓ［１，２］使用３５ｍｍ。幻灯片对一个物体连续...     

360°反射式全息照相

杰亨与他的学生们已经照出了物体的360°的透射式全息图。我们也成功地造出了360°反射式全息图。并且象DENISYUK类型的平面反射式全息图一样能用白色光源去观察。本文报导了制作优质的360°反射式全息图的两种方法。全息图分为透射式或反射式,取决于图象的重现是用透射光或是用反射光。为     

Righi-Leduc Effect in InSb between 25°C and 300°C

The Righi-Leduc effect has been measured for n-type InSb crystals of various mobilities and was found to increase with temperature in a manner to indicate that the unipolar contribution is prevalent over the bipolar part of the effect. The experimental values measured over the temperature range between 25°C and 300°C agree well withPutley's theory. The Righi-Leduc coefficient was also determined as a function of the magnetic field and the strong decrease observed is explained in terms of the magnetoresistance.     

Electrical conductivity of slightly reduced rutile between 2° and 370°K

Abstract

The electrical resistivity and the Hall coefficient of slightly reduced rutile crystals were measured in the temperature range between about 2 °K and 370 °K. The time of reduction treatments between 900 °C and 1300 °C was usually as long as 300 hrs, which assures the homogeneous reduction of crystals, The conduction mechanisms in three temperature ranges, i. e. 1. 9～3°K, 3～100°K and 100～250°K, were discussed in terms of lattice defects evidenced by ESR studies.     

Ⅰ-Ⅱ-90°-90°合像棱镜的加工

F Ⅱ-90°-90°合像棱镜由三块直角棱镜组成,有几个反射面,并要求有良好的像质和很长的焦距,因此加工比较困难。下面谈谈我们加工这种棱镜的体会。这种棱镜的形状和技术要求如图1所示:     

Two Dimensional 1HNMR Studies on 2′5′-Dideoxyadenosylcobalamin

The ¹HNMR spectrum of 2′,5′-dideoxyadenosylcobalamin, a Coenzyme B₁₂(5′-deoxyadenosylcobalamin) analogue, has been assigned by 2D COSY. Its proton coupling constants have also been measured by J-resolved experiment. The comparison between the analogue and Coenzyme B¹² was made.     

简易180°聚焦β谱仪

本文描述一台简易的180°聚焦β谱仪。谱仪的电子运动轨道平均半径是100mm,谱仪的均匀磁场是由单轭磁铁所产生的。D形真空室高70mm,利用磁极面作为底盖,用橡皮垫圈密封,谱仪的磁场测量采用“零点测磁仪”,测磁仪的心脏部分是一个偏心地安装在张紧的钨丝上的小的测量线圈,要使线圈在磁场中保持某一特定方向,就得使通过线圈的电流随着磁场的变化而作相应的改变,使得电磁作用所产生的力短和作用于线圈的机械力矩相平衡。因为重力矩固定不变,通过线圈电流的大小将和磁场强度成反比,测量所得电流读数可以作为磁场强度的度量,包括磁场测量在内谱仪测量总的线性和重复性都在0.1％左右。经过调整和改进以后,谱仪目前的最好的分辨率是0.7％,那是利用源宽0.8mm的Hg¹⁹⁸K内转换谱线测得的。对于源宽2mm的Ba¹³⁷K内转换谱线我们测得的谱仪分辨率是0.9％。谱仪的主要优点在于它的简易。     

顶角60°棱镜的测定方法

我们改革了一种建立在已知折射率,井在测定不同波长最小偏角基础之上,测量顶角60°棱镜的方法。发现顶角测定误差小于3％,用该方法补充光学实验室中所使用的其它测量方法。     

The decays of theρ′1 andω′1 mesons

New measurements of the reactione ⁺ e ^– confirm previous evidence for the decay₁ and provide a strong constraint on the mass of the₁. The results from a detailed analysis of these data are compared with those from a corresponding analysis of new data on the reactione ⁺ e ^–. It is shown that in accord with expectation. This identification of a strong₁ decay supports a previous claim that the₁ and theC(1480), observed in the channel, cannot be different manifestations of the same particle.     

In-Medium η′ Mass Reduction

In this talk, we present the reduction of the mass of η′-meson at finite temperature which leads to the enhancement of η′ contributions to the dilepton spectra from relativistic heavy ion collisions. QCD low energy theorem, together with the Witten–Veneziano formula, provides the relation of the η′ mass with gluon condensates.     

Pulsed ESR on the organic ion radical salt: 3,3′-diethyl-4,4′-dimethyl-2,2′-thiazolocyanine-[TCNQ]2

We present firstT _1e ^?1 andT _2e ^?1 measurements on the organic ion radical salt 3,3′-diethyl-4,4′-dimethyl-2,2′-thiazolocyanine-(TCNQ)₂ as function of temperature and of orientation. The electronic spin diffusion constant could be determined directly by the electron spin echo field gradient technique:D (300 K)=0.03±0.02 cm²/sec. Pulsed ESR experiments have — in comparison to conventional cw-ESR — the advantage to monitor viaT _1e ^?1 andT _2e ^?1 the spectral density of dynamical processes at different frequencies. This is shown in a general manner on 3,3′-diethyl-4,4′-dimethyl-2,2′-thiazolocyanine-(TCNQ)₂. Between 300 and 60 K,T _1e ^?1 andT _2e ^?1 are close in amplitude and have a similar temperature dependence. At 60 K their degeneracy is lifted, yielding a quantitative value for the effective spin exchange between localized spinsτ _ex ^?1 sec^?1 and via the absolute value of the relaxation an average distance of the localized centers of about 12 Å. The dynamical data as evaluated above cannot be correlated with the conductivity, clearly indicating that the conduction electrons are a minority, not being monitored by the ESR-experiments.     

CEBAF和质子G°实验研究

本文简单介绍了美国ＣＥＢＡＦ（连续电子束流加速器）的近况和研究方向,以及Ｃ厅将展开的研究核子内Ｓ夸克成分的极化电子与质子散射宇称破坏不对称性测量的实验,即质子味单态电形状因子Ｇ°实验． The current status and scientific goal of CEBAF (The continuous Electron Beam Accelerator Facility ) are briefly presented. The project of the measurement of the flavor Singlet form factor G°of proton at C hall is outlined. A precise measurement of Parity violating asymmetry in the scattering of polarized electron from a proton target enables one to explore the Strange quark content in the proton.     

为什么要小于45°角推铅球

中专物理教材中谈及,若抛射体的初速较小,空气阻力可以忽略,抛射角约为45°的射程最大,若抛出点的位置较高,取得最大射程的抛射角并不是45°,一般小于45°,例如中学生投铅球、掷标枪等,抛射角应为40°左右,这是为什么?     

ВОСТОЧНО-ЗАПАДНАЯ АС ИММЕТРИЯ НА 48 °N ГЕОМАТ НИТНОЙ ШИРОТЫ

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East-West Asymmetry on the 48 °N of the Geomagnetic Latitude