Contact creep as the principal source of the losses associated with the rolling of a plastic ball

An engineering method is proposed for calculating the contact creep of plastic balls used in rolling bearings. The method is based on empirical expressions relating the relative creep strain with the specific load and its duration of action. The complex contact-creep characteristics of the material are obtained by means of simple laboratory tests.Moscow Bauman Higher Technical College. Translated from Mekhanika Polimerov, No. 3, pp. 498–504, May–June, 1969.     

Electronic structure of the pyrimidine and purine components of nucleic acids in their ground and lower excited singlet and triplet states

Quantum-chemical calculation of the energies of the electronic transitions and the electronic structures of the neutral and ionic species of the nucleic acids components in their ground and lower excited singlet and triplet ππ* and nπ* states has been carried out in the all-valence-electron approximation CNDO /S . The results of the calculation allow one to identify the most photoreactive sites of the molecules and to consider the dependence of the location of these sites on the ionic state of the molecules. The calculated data are compared with our previous results obtained in a π-electron approximation. The individual absorption spectra of various ionic and tautomeric species of the nucleic acids components obtained by us earlier have been decomposed into bands corresponding to separate electronic transitions. As a rule, there is a good agreement between the calculated data in the two approximations and the experimental results.     

各种U1规范理论和具有一标量泛函的U1主丛的Riemann几何

本文利用包含一个规范不变的标量函数或泛函的U₁主丛的Riemann几何,重新考查了包括Maxwell理论、Born-Infeld理论、Johnson型禁闭理论和有质U₁规范理论等各种U₁规范理论,并提出了一种“电子泡”模型的规范场作用量,所有这些理论可以表示为某种Minkowski时空上的Kaluza型理论。文中还提出了一种标量-矢量规范理论的作用量,其中的标量场作为独立的动力学变量表征真空的性质。 基于检验粒子沿丛上测地线运动的假定,我们得到了在这些场中运动的粒子的荷质比守恒方程和运动方程。     

类氖锗的X射线激光增益及其传输特性研究

在神光(10¹²W)装置上,用1.06μm激光加热片状锗靶,用袖珍式掠入射光栅谱仪测量了类氖锗离子的3S—3P激光跃迁线的增益系数和X射线激光的传输特性,得到的结果为:波长为19.638,23.224,23.627,24.743和28.643nm的5条激光跃迁线的增益系数分别为3.06,3.99,3.72,2.36和4.59cm^-1;当等离子体长度为18mm时,相应的X射线激光的发散角约为12mrad,发射X射线激光的等离子体厚度约为200μm,X射线激光峰值强 关键词：