New inverse method for identification of constitutive parameters

A new inverse method by coupling iSIGHT and ABAQUS was proposed to determine the constitutive parameters of Al2O3sf/LY12 composite deforming at elevated temperature. It combined the merits of the f＇mite element simulation and optimization technique. The direct model was simulated with finite element code ABAQUS. The inverse problem associated with the identification of the constitutive parameters was expressed as a least square optimization problem. The direct simulation and the parameters optimization were implemented in iSIGHT integrated environment. The aim was to match the output of the direct simulation with the experiment data. The capability of the proposed inverse method was demonstrated through the identification of constitutive parameters of Al2O3sf/LY12 composite. The proposed new inverse method is also applicable to other parameters identification which is hardly determined through experiments or direct analytical method.     

深冲汽车簿钢板织构的表述方法

利用晶体学性质,将深冲汽车薄板的两种主要特征织构表述于反极图之中,再利用织构定量技术便能简捷地分析深冲钢板的织构与深冲性能的关系。经验证,此法与ODF定量分析所得的结果一致。     

The internal nitriding behavior of Co-3Cr,Co-3Al,and Co-3Ti (a/o) over the range of 700–1100°C

Internal nitridation of Co containing 3 a/o of either Cr, Al, or Ti was studied over the range of 700–1100° C in NH₃/H₂ (694 ratio). The kinetics of thickening of the reaction zone followed the parabolic rate law, suggesting that solidstate diffusion was rate controlling. Activation energies obtained were 51.2 Kcal/molfor Co-3Cr, 46.6 Kcal/mol for Co-3Ti, and 27.9 Kcal/mol for Co-3Al. XRD showed only CrN, AlN, and TiN. Deep etching revealed that AlN formed hexagonal plates near the surface when formed at high temperature, the precipitates becoming more massive (blocky morphology) near the reaction front. TiN formed elongated dendritic precipitates, whereas CrN tended to form spheroids. The precipitate size varied with temperature, decreasing with decreasing temperature. In some cases, nitriding formed a case but no visible precipitates even at very high magnifications in the SEM. The solubility of nitrogen in cobalt was determined by long-time equilibration and subsequent chemical analyses. The diffusivity of nitrogen in cobalt was determined from measured permeabilities and the experimentally determined solubilities. Mechanisms are discussed, and the behavior of internal nitridation is compared with internal carburization and oxidation in cobalt alloys.     

尖山铁矿破碎机硐室围岩位移反分析及稳定性评价

推导了非均匀应力场下硐室（或隧道）的位移反分析公式，并利用尖山铁矿破碎机硐室围岩位移监测结果反演了围岩的力学参数。计算了硐室周围应力并对其稳定性作了分析评价。     

Determination of the solubility parameter of poly(ethylene oxide) at 25°C by gas-liquid chromatography

The solubility parameter of poly(ethylene oxide) at 25°C has been determined using the method developed by DiPaola-Baranyi and Guillet, by the extrapolation of the values of the interaction parameter χ, at high temperatures, ranging from 70°–90°, 90°–110° and 110°–130°C down to 25°C. The values of the solubility parameter obtained, depending on the temperature ranges employed, are 9.8, 9.9 and 10.1, respectively.     

Selective solvation of polystyrene in tetralin/cyclohexane mixtures

Refractive index increments and density increments have been measured at 307.6K for polystyrene in binary solvents of 1,2,3,4-tetrahydronaphthalene (tetralin, TET) and cyclohexane over the whole range of solvent composition. Comparison of these increments with the corresponding values obtained at dialysis equilibrium (i.e. at constant chemical potential of low molecular weight species) yielded the coefficients of selective adsorption (γ₁) of TET by the polymer. Positive values of γ₁ were exhibited at solvent compositions up to 78% (v/v) of the thermodynamically better solvent, TET. Theoretical curves of γ₁ vs. composition were calculated on the basis of, firstly, relevant interaction parameters and, secondly, interaction parameters in conjunction with solubility parameters. Both procedures afforded self-consistent results, which were, however, uniformly lower than the experimental values of γ₁.     

5’-单磷酸腺苷在乙醇-水中介稳区性质研究

针对5’-单磷酸腺苷(5’-AMP)在溶析结晶中易出现爆发结晶的问题,分别采用静态法和激光法测定了293—323 K下5’-AMP在纯水以及溶剂体积比为0.3—2.0的乙醇-水体系中的溶解度和超溶解度,以指数经验关联式建立了超溶解度关联式,并在试验条件下考察了温度、乙醇流速、pH值和搅拌速率对介稳区宽度的影响。运用中心复合设计预测了5’-AMP在本溶析结晶体系中介稳区间,并用扫描电镜观察了5’-AMP在结晶条件优化前后晶体形态的变化情况,为工业生产中提高结晶产品质量提供了理论指导。     

Effect of ortho- and pyrophosphates on dissolution of Fe,Al, Si,Ca, and organic C in three soils

Phosphate application changes chemical properties of surface soils, consequently influencing crop nutrient availability and pedological process. Sodium ortho- (OP) or pyrophosphate (PP) was equilibrated with three Quebec soils: an Uplands sand (Orthic-Podzol), a St. Bernard loam (Eutric-Cambisol), and a Dalhousie clay (Humic Gleysol) in 0.03 M KClO₄ solution at an initial pH 6.0. Both autoclaved and nonautoclaved soils were used, and dissolution of Fe, Al, Si, Ca and organic C was studied.Concentrations of Fe and Al in OP equilibrated solutions were not detectable. Ca solubility was reduced while dissolution of Si and organic C was increased in the presence of OP. These changes were possibly due to P—Ca precipitates or increased Ca sorption by P, and competition between OP and Si or organic materials for sorption sites. PP enhanced dissolution of Fe, Al, Si and organic C but reduced solubility of Ca. Comparisons showed that PP added to autoclaved soils had greater effects on increasing dissolutions of Fe, Al, Si and organic C and on reducing Ca solubility than OP in both autoclaved and nonautoclaved soils. Autoclaving resulted in greater dissolution of organic C. Dissolved Si with added OP was greater with nonautoclaved soils probably due to more P sorption in the nonautoclaved system, compared with autoclaved soil. Added PP dissolved Fe and Al ions which may ultimately enhance P precipitation by forming less soluble compounds upon hydrolysis of PP to OP.     

数字皮影动画脚本的研究与应用

为简化数字皮影动画的制作流程,提高数字皮影作品的交互性,降低数字皮影实时表演的难度,对皮影常见角色及动作进行了抽象、分类,提出一种针对特定类型的通用的骨骼模型。基于反向动力学,设计了一套描述皮影骨骼动画的脚本。该脚本通过对骨骼位置与旋转属性的控制定义皮影角色的基本动作,并通过对基本动作的叠加实现复杂动作。脚本对动作的定义基于骨骼模型而非具体角色,具有通用性。最后通过实验证明了脚本的有效性。     

SOLUBILITY OF CO2 AND H2S IN A HINDERED AMINE SOLUTION

The solubility of H₂S and CO₂ in aqueous solutions of the sterically hindered amine, 2-amino-2-methyl-1-propanol (AMP), was determined at 40 and 100°C. Partial pressures of C)₂ ranged from approximately 2 to 6000 kPa and of H₂S from 2 to 2200 kPa. The solubility results were compared with previously reported acid gas solubilities in aqueous monoethanolamine (MEA) solutions.