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51.
The elasto-plastic-damage behavior of anisotropic aluminum alloys is investigated under finite deformation using a physical mechanism based constitutive model. With an application to the structural calculation, the present model is used to describe and analyze the mechanical response of anisotropic 6260-T6 aluminum alloy extrusions. For the tensile specimens extracted along three different material orientations from the extruded aluminum profile, twelve simulations are carried out covering four different specimen geometries. The simulation results in force-displacement response and central logarithmic axial strain evolution are compared with experimental results. From the comparisons, it can be concluded that the present model has the capacity to describe the behavior of anisotropic material. From the force-displacement curves, the anisotropy is observed in different material orientations, and the physical mechanism of anisotropy is analyzed. 相似文献
52.
离子交换法分离乳酸的连续流动板模型 总被引:3,自引:0,他引:3
本文对乳酸在D354树脂上的离子交换行为进行了详细的研究,并在乳酸的超摩尔离子交换等温线方程的基础上,进一步采用简单的连续流动板模型对乳酸的固定床离子交换行为进行描述,模型拟合结果与实验值能较好的符合。 相似文献
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55.
多级孔ZSM-5分子筛的制备及催化噻吩烷基化性能研究 总被引:1,自引:0,他引:1
多级孔ZSM分子筛的制备及催化噻吩烷基化性能研究 《燃料化学学报》2013,41(10):1256-1261
用不同浓度的Na2CO3溶液处理ZSM-5分子筛,采用XRD、XRF、SEM、N2吸附脱附及NH3-TPD方法对处理前后的ZSM-5分子筛进行表征,并考察了Na2CO3溶液处理对ZSM-5分子筛孔结构、酸性以及噻吩烷基化性能的影响。结果表明,Na2CO3溶液处理在保持ZSM-5分子筛微孔骨架结构的同时,增加了ZSM-5分子筛的比表面积、外表面积和介孔体积,并调变了酸性。Na2CO3溶液处理提高了ZSM-5分子筛催化剂的噻吩烷基化活性和噻吩选择性。一定反应条件下,随着Na2CO3溶液浓度增加,多级孔ZSM-5分子筛的噻吩烷基化性能逐渐提高,而噻吩选择性先增加后下降。当Na2CO3溶液浓度为2 mol/L时,分子筛的噻吩转化率和噻吩选择性分别为81.26 %和73.15%。当Na2CO3溶液浓度为3 mol/L时,噻吩转化率和选择性分别为90.57 %和72.59%。 相似文献
56.
A group G is said to satisfy the maximal permutizer condition if the permutizer of any maximal subgroup M of G in G, PG(M), is G. In this paper, we characterize the supersolubility of finite groups by using the maximal permutizer condition. We also get some results for when both G/N and N are supersoluble, which implies that G is supersoluble. Our results unify or generalize some known results. 相似文献
57.
Fei Wang Dong Liu Ke-fa Cen Jian-hua Yan Qun-xing Huang Yong Chi 《Journal of Quantitative Spectroscopy & Radiative Transfer》2008,109(12-13):2171-2181
An efficient numerical inverse radiation analysis based on the backward Monte Carlo (BMC) method is presented to determine the three-dimensional (3-D) temperature distribution in a large rectangular enclosure containing the participating medium, using radiative intensities in the visible range received by charge-coupled device (CCD) cameras. For large radiative sources and small detectors, when the radiation onto a small spot and onto a small direction cone is desired, the BMC method is more efficient than the forward Monte Carlo (FMC) method. Because the temperature reconstruction from the measured radiative intensities is an ill-posed inverse problem, least-square QR decomposition (LSQR) method is introduced to determine the meaningful temperature distribution. In order to gain insight into the effects on the accuracy of temperature distribution reconstruction, the detailed analyses are made using numerical simulations. The results show that the temperature distribution can be reconstructed accurately for the exact and noisy data. 相似文献
58.
Recently, a 4-node quadrilateral membrane element AGQ6-I, has been successfully developed for analysis of linear plane problems. Since this model is formulated by the quadrilateral area coordinate method (QACM), a new natural coordinate system for developing quadrilateral finite element models, it is much less sensitive to mesh distortion than other 4-node isoparametric elements and free of various locking problems that arise from irregular mesh geometries. In order to extend these advantages of QACM to nonlinear applications, the total Lagrangian (TL) formulations of element AGQ6-I was established in this paper, which is also the first time that a plane QACM element being applied in the implicit geometrically nonlinear analysis. Numerical examples of geometrically nonlinear analysis show that the presented formulations can prevent loss of accuracy in severely distorted meshes, and therefore, are superior to those of other 4-node isoparametric elements. The efficiency of QACM for developing simple, effective and reliable serendipity plane membrane elements in geometrically nonlinear analysis is demonstrated clearly. 相似文献
59.
In this paper we consider a singularly perturbed quasilinear boundary value problem depending on a parameter. The problem is discretized using a hybrid difference scheme on Shishkin-type meshes. We show that the scheme is second-order convergent, in the discrete maximum norm, independent of singular perturbation parameter. Numerical experiments support these theoretical results. 相似文献
60.
研究了DNA与铜(Ⅱ)-L丝氨酸-二吡啶并[3,2-a:2',3'-c]吩嗪配合物[Cu(DPPZ)(L-Ser)-]+相互作用的共振光散射光谱和紫外可见吸收光谱,通过研究体系与溴化乙啶相互作用的荧光光谱特征,证明其作用方式为插入作用.在pH 7.2的缓冲溶液中,[Cu(DPPZ)(L-Ser)]+由于插入作用而在DNA表面聚集,使体系的共振光散射强度增强,最大敞射峰在400 nm处.在最佳实验条件下,共振光散射增强的强度与浓度在0.42~4.20 ng·mL1范围的DNA具有良好的线性关系.方法的检出限为0.29 ng·mL-1.该法用于DNA样品的测定,回收率在97.8%~106.0%之间. 相似文献