Electromagnetic form factors of3He and3H

The electric and magnetic form factors of³He and³H are calculated with 3-nucleon wave functions obtained from the solution of Schrödinger equation with separable potentials of two different shapes which have already been employed in the coulomb energy calculation. The effect of important meson exchange corrections is evaluated and their dependence on the wave function studied. The form factors can depend rather sensitively on the nucleon form factors as well, and this dependence is studied by using two different parametrisations for the latter.     

Spectroscopic investigations on cometary molecules CO, CH and CH

The experimental potential energy curves for the electronic ground states of molecules like CO⁺, CH and CH⁺ observed in comets are constructed by using the Rydberg-Klein-Rees method as modified by Vanderslice et al. The ground state dissociation energies are determined by curve fitting technique using the five parameter Hulburt-Hirschfelder (H-H) function. The estimated dissociation energies are 8.33±0.19, 3.48±0.903 and for CO⁺, CH and CH⁺, respectively. These values are in good agreement with the literature values. Estimated dissociation energies of CO⁺, CH and CH⁺ are used in the relation given by Gaydon and ionization potentials are evaluated for CO and CH molecules. The estimated ionization potentials are 14.03 and , respectively for CO and CH. The Franck-Condon factors and r-centroids for the band system of - of CO⁺ molecule have been calculated employing an approximate analytical methods of Jarmain and Fraser. The absence of the bands in this system is explained.     

Calculs de facteurs epsilon de paires sur un corps local, II

Let F a locally compact non-Archimedean field, of residue characteristic p, and a nontrivial additive character of F. Let , be irreducible representations of the absolute Weil group of F, each of degree a power of p and not induced from a nontrivial unramified extension of F. We give a formula for the value at , modulo roots of unity in of order a power of p. Via the Langlands correspondence, we get an analogous formula for supercuspidal representations of GL_n(F).     

MRI检查神经根沉降征诊断LSS患者的价值及其危险因素分析

本研究探讨磁共振成像(MRI)检查神经根沉降征(NRS)在腰椎管狭窄症(LSS)患者发生中的相关因素及其诊断学价值。选取接受腰椎MRI检查的262例(511个腰椎节段)患者进行研究,根据MRI结果患者腰椎节段分为狭窄组(172例患者,348个腰椎节段)和非狭窄组(90例患者,163个腰椎节段)。狭窄组硬膜囊面积(CSA)<100 mm²患者占比、椎管正中矢状径(PDA)≤15 mm患者占比、侧隐窝矢状径≤5 mm患者占比、神经根沉降征(NRS)阳性率均显著高于非狭窄组(P<0.05);NRS诊断LSS的曲线下面积(AUC)值为0.714;172例LSS患者,NRS阳性患者108例、NRS阴性患者64例,NRS阳性组的糖尿病率、硬膜囊CSA<100 mm²患者占比、椎管PDA≤15 mm患者占比、侧隐窝矢状径≤5 mm患者占比均高于阴性组患者,差异均具有统计学意义(P<0.05);硬膜囊CSA<100 mm²、椎管PDA≤15 mm、侧隐窝矢状径≤5 mm是LSS患者发生NRS的独立危险因素(P<0.05)。NRS对于诊断LSS具有较高的特异度,但是灵敏度一般,患者椎管狭窄越严重,其NRS发生的风险越高。     

“元素化学实验”中的“异常”现象(一)--Mn元素化学实验中的“异常”现象及其探析

大一学生在“元素化学实验”教学过程中,对反应条件如温度、催化剂、酸度、浓度或试剂用量等因素的影响考虑不周,可能出现某些实验现象和预想的或理论分析的结果不一致的“异常”现象。本文就学生在Mn元素化学实验过程中遇到的一些“异常”现象进行分析和总结,借助生动直观的演示实验,引导学生探究“异常”现象产生的可能原因和直观认识反应条件对反应结果的影响,培养学生的观察、分析、判断、归纳、推理和解决实际问题的能力。     

高职院校课堂教学质量影响因素研究——基于Lasso-logistic回归模型

本文以"大学生课堂学习状态问卷"调查为基础,利用Lasso-logistic回归模型对安徽省某高职学院336位学生成绩的影响因素进行分析。结果表明,影响客观评价结果的因素包括性别、父母亲文化程度等个人、家庭因素及学习勤奋刻苦程度等直接相关因素;而影响主观评价结果的因素则主要为学习勤奋刻苦程度、学习目标等直接相关因素,而不包括个人、家庭因素。     

功能梯度材料的平面断裂力学分析

针对材料参数在厚度方向可能按任意连续变化的梯度材料，给出了一个新的分层模型，利用该模型求解了面内加载下梯度界面层和涂层中的界面裂纹问题，借助Fburier积分技术和传递矩阵方法，将该问题化为一个Cauchy型奇异积分方程，通过数值求解，得到感兴趣的应力强度因子，对不同形式的杨氏模量和泊松比，计算了界面裂纹应力强度因子，结果表明泊松比的变化形式对应力强度因子影响不大，可当作常数处理，而杨氏模量的影响则很大。     

Propagation of an anti-plane moving crack in a functionally graded piezoelectric strip

Summary The propagation of an anti-plane moving crack in a functionally graded piezoelectric strip (FGPS) is studied in this paper. The governing equations for the proposed analysis are solved using Fourier cosine transform. The mixed boundary value problems of the anti-plane moving crack, which is assumed to be either impermeable or permeable, are formulated as dual integral equations. By appropriate transformations, the dual integral equations are reduced to Fredholm integral equations of the second kind. For the impermeable crack, the stress intensity factor (SIF) of the crack in the FGPS depends on both the mechanical and electric loading, whereas, the SIF for the permeable crack depends only on the mechanical loading. The results obtained show that the gradient parameter of the FGPS and the velocity of the crack have significant influence on the dynamic SIF.Support from the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. HKU 7081/00E) is acknowledged. Support from the National Natural Science Foundation of China (Project No. 10072041) is also acknowledged.     

各向异性板应力强度因子的分区广义变分解法

本文以单边边缘裂纹二维应力场与位移场的级数展开式为基础,以分区广义变分原理求解含双边非对称边缘裂纹板的应力强度因子。首先建立精确满足各向异性板基本微分方程和裂纹表面边界条件的应力场和位移场的本征展开式,然后用分区广义变分原理满足其余边界条件与交界连续条件并由此确定应力强度因子。在变分方程中只有沿板边界的线积分。计算程序简单,输入数据很少,结果收敛迅速并与已有结果完全吻合,同时计算节省机时与人力。本文还给出了有关的全新计算曲线。