圆孔边缘裂纹扩展过程中裂纹周围的动态塑性应变测量

本文用面内云纹法和影象云纹法结合高速摄影技术,对带孔铝板在突加载荷作用下孔边裂纹扩展过程中裂纹周围的应变场进行分析。用等应变线表达断裂过程中相应时刻的应变场,最大动应变可达0.9。本试验也得到了材料的裂纹扩展速度和撕裂模量。     

On nonconservativeness of Eringen’s nonlocal elasticity in beam mechanics: correction from a discrete-based approach

In this paper, the self-adjointness of Eringen’s nonlocal elasticity is investigated based on simple one-dimensional beam models. It is shown that Eringen’s model may be nonself-adjoint and that it can result in an unexpected stiffening effect for a cantilever’s fundamental vibration frequency with respect to increasing Eringen’s small length scale coefficient. This is clearly inconsistent with the softening results of all other boundary conditions as well as the higher vibration modes of a cantilever beam. By using a (discrete) microstructured beam model, we demonstrate that the vibration frequencies obtained decrease with respect to an increase in the small length scale parameter. Furthermore, the microstructured beam model is consistently approximated by Eringen’s nonlocal model for an equivalent set of beam equations in conjunction with variationally based boundary conditions (conservative elastic model). An equivalence principle is shown between the Hamiltonian of the microstructured system and the one of the nonlocal continuous beam system. We then offer a remedy for the special case of the cantilever beam by tweaking the boundary condition for the bending moment of a free end based on the microstructured model.     

冷蒸气原子吸收光谱法测定铜精矿中的汞

本文研究了一种用冷蒸气原子吸收光谱测定铜精矿中汞的方法。铜精矿用逆王水或硫酸-高锰酸钾(固)消化后用测汞仪测定其中的汞含量。测定结果的相对标准偏差小于5%;回收率在92-107%之间。     

Reduction of ketones to corresponding alcohols with magnesium metal in absolute alcohols

Various aliphatic and aromatic ketones are treated with 10 equiv of magnesium metal in absolute methanol or ethanol to afford corresponding alcohols in very high yields at room temperature within 12 h.     

火焰原子吸收光谱法测定水中铁,锰,镉

本文研究了用火焰原子吸收光谱法进行水分析的条件。而且还找到了水分析中质量控制实验的方法。用这些方法对IEHM9202WT1标样中铁、锰和镉三种元素进行分析的结果能很好的符合技术条件所规定的值。     

富稀土元素合金中镧,铈,镨,钕,钐测定方法的研究

本文用美国Jarrell-Ash 9000型多道光量计,采用无基体匹配法对富稀土元素合金中镧、铈、镨、钕、钐进行了测定分析。对稀土元素较复杂的光谱干扰运用元素间干扰系数和自身干扰系数校正法进行校正。对其非光谱干扰采取加入内参比进行补偿。通过人工合成样分析和实际富稀土元素合金样品加标准回收实验,表明干扰系数内参比法是一种有前途的无基体匹配的定量分析法。     

百焦耳KrF激光器腔体的设计和激光实验

1990年原子能科学研究院建成一台百焦耳KrF激光器,最大能量输出达106焦耳。本文介绍激光器腔体主要结构参数的选定和激光实验。     

Minoration du volume de grosses boules des groupes de Lie semi-simples

SoitG un groupe de Lie semi-simple, muni d’une distance invariante à guache. On s’intéresse au comportement, du volume des boules quand le rayon tend vers l’infini. On en déduira des estimations de la fonction maximale.     

Une variante de l’inegalite de Hardy

On prouve une version de l’inégalité de Hardy pour les groupes.     

Study on the Formation of Urea or Salt Induced Vesicles in Built-system Surfactant

The spontaneous formation of vesicles in the aqueous of cationic surfactant phosphate (PTA) and anionic surfactant sodium dodecyl sulfate (SDS) at certain mixing ratios have obtained^1. The addition of urea or Nal will expand the range of spontaneous vesicle formation. The fact is demonstrated by negative-staining transmission electron microscope(TEM) and dynamic light scattering(DLS) methods. The phenomenon especially in the part of urea is reported by us at first. Mechanism of urea/Nal-induced vesicles formation is discussed from the viewpoint of the molecular geometry packing parameter f, conformation and interaction.