Relaxation mechanism of rotational type in fracture of weld joints for austenic steels

Studied is the mesoscale behavior of plastic deformation and fracture of weld joints for austenic steels. Large-scale rotational modes of deformation in heat affected zones are identified with the first stage of formation of band structures; it is related to the “traveling neck” phenomenon in the base metal. The second stage is connected with crack generation and the state of affairs in the heart-affected zone.     

Determination of ionization constants of saccharides by capillary zone electrophoresis with amperometric detection

Summary A method based on a linear model enabling the efficient determination of the ionization constants (K _a) of saccharides by capillary zone electrophoresis with amperometric detection has been demonstrated. TheK _a values obtained from the plots of the reciprocal effective mobility against the inverse concentration of sodium hydroxide were in agreement with literature values.     

菲涅耳编码孔成象研究

编码孔成象(CAI)是一种高分辨率、高信噪比、高集光效率和大视场的成象技术。可适用的技术领域有:脉冲射线成象、实时图象跟踪、层析摄影术(tomography)等高技术领域本文探讨了CAI技术的一般理论,重点讨论了菲涅耳波带片的编码成象及解码复原的原理、方法、实验及处理结果并指出了实验难点及结果误差。     

Optimization of separations of alkyl-substituted phenolate anions by capillary zone electrophoresis

Anions of alkylphenols have very similar electrophoretic mobilities in CZE owing to their very small differences in size and the narrow range of their pK_a values. By studying electrophoretic mobility as a function both of pH and of the amount of acetonitrile in the electrolyte solution, optimum separation conditions were determined. It was possible to separate a group of methyl-substituted phenols, including several positional isomers. Mixtures containing n-propyl and isopropyl phenols and 1°, 2°, and 3° butylphenols could be resolved.     

Electromigration of ionic micelles by the use of an isotachophoretic apparatus

Electromigration experiments of ionic surfactants were performed by using a capillary tube isotachophoretic apparatus. The zone of the migrated surfactant was collected after separation, and the surfactant concentration of the migrated zone was determined by HPLC analysis. The surfactant concentration of the migrated zone was increased with an increase in electrolyte concentration, and was in accord with the prediction of the Kohlrausch equation. When the electrolyte concentration further increased, the surfactant molecules began to migrate as a micellar state. Moreover, the mixed systems of ionic-non ionic and ionic-ionic surfactants were also examined and revealed the migration as mixed micelle.     

ψ-correct decision for selection and elimination

Summary The selection oft out ofk populations with parameters θ _i (i=1, ...,k) is said to result in an ψ-correct decision provided ψ (minimum selected θ)>maximum non-selected θ where ψ(θ) (>θ) is an increasing function. For the cases of location or scale parameters the minimum probability of ψ-correct decision over the entire parameter space is shown to be no less than the minimum probability of correct selection over a preference zone determined by ψ(θ). For other types of parameters this result is shown to be true under certain conditions linking the distribution function and the ψ function.     

扩展裂纹尖端奇异场的实验研究

用云纹方法测量了 LY12-M 铝材,双边裂纹试件、扩展裂纹沿 x和y方向位移场u_x,u_y。实验的裂纹尖端奇异场与 GH 理论奇异场进行了比较。两者偏差在±10％范围内,得到实验的 GH 奇异场范围与形状。实验证明:扩展裂纹尖端场有(lnA/r)~(α+1)奇异主导区。该主导区形状由腰子形向扁圆、圆形过渡,接近裂纹扩展时形状不规则。在 GH 主导区内,裂纹尖端附近有一个三维贲形,材料损伤区。在该区内 GH 奇异性不存在。