TiNi形状记忆合金的线性回复行为及其稀土渗入改性

提出了TiNi形状记忆合金线性回复行为的新概念，采用稀土表面渗入化学热处理的方法，研究了对其线性回复性能的影响。实验结果表明：对TiNi形状记忆合金弹簧渗铈(Ce)或渗钐(Sm)，可以显著改善其线性回复性能。线性回复温度范围Tw从4℃拓宽到11℃，线性回复率η从54％提高到78％，线性回复程度PL从56％提高到70％，非线性回复程度Ps从44％减小至8％，但总回复程度PT有所下降。这些结果是由于TiNi合金弹簧渗层中金属问化合物的强化效果所致。     

装饰用铝箔的质量控制

简要介绍了我公司生产的3种装饰用铝箔的质量控制措施，使3种铝箔的力学性能、表面质量、板形等满足用户的使用要求。     

Cu-Al-Be形状记忆合金的应力腐蚀性能

用恒载荷法和慢应变速率法及SEM研究了Cu-Al-Be形 状记忆合金在甘油、海水和氨介质中的应力腐蚀性能.结果表明，Cu-Al-Be合金具有良 好的抗海水应力腐蚀性能和较低的氨介质应力腐蚀倾向.单相马氏体有较 好的耐海水腐蚀能力，可减少腐蚀引起的裂纹源；外应力下马氏体的孪晶变形和变体间的界 面迁移，则有利于松弛应力集中，阻碍和延缓腐蚀裂纹源的扩展，从而提高Cu-Al-Be合金的 应力腐蚀能力.     

A distribution kinetics model for chromatography of block-like molecules

We develop the theory for chromatographic separation of isomers such as polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dioxins, steroids, and carotenoids based on shape-selective mechanisms for either exclusion or adsorption. Block-like solute transport and retention on oriented stationary phases are modeled by a dispersed-flow chromatographic equation combined with simultaneous exclusion partitioning and shaped-based adsorption. Molecules to be separated are considered distributed continuously with respect to the shape and sorption parameters. The population balance equations of distribution kinetics provide the governing differential equations that are solved for the temporal moments of the concentration in a chromatographic column. By including dispersive mass transport effects, the model allows estimation of peak variance and HETP and is thus an improvement over theories that focus solely on retention time. The model predictions are compared with experimental data from the literature for gas chromatography.     

Detecting symmetries of rational plane and space curves

This paper addresses the problem of determining the symmetries of a plane or space curve defined by a rational parametrization. We provide effective methods to compute the involution and rotation symmetries for the planar case. As for space curves, our method finds the involutions in all cases, and all the rotation symmetries in the particular case of Pythagorean-hodograph curves. Our algorithms solve these problems without converting to implicit form. Instead, we make use of a relationship between two proper parametrizations of the same curve, which leads to algorithms that involve only univariate polynomials. These algorithms have been implemented and tested in the Sage system.     

Rheological properties of bitumen in water emulsions with added solids

Experimental work was carried out to investigate the rheological properties of bitumen in water emulsions containing solids of different shape and size. The bitumen volumetric concentration was varied up to 60%, solids free basis, and the solids volume fraction (total volume basis) was varied up to 0.2. Irregular-shaped silica sand (average diameter: 9 and 33 μm) and smooth spherical glass beads (average diameter: 27 and 44 μm) were used as the added solids. In the low shear stress range, shear thinning behavior was observed for bitumen in water emulsions. At high shear stress, the viscosity of the emulsions became fairly independent of the shear stress. The addition of solids to the bitumen emulsions increased the mixture viscosity. The addition of irregular-shaped silica sand gave a higher viscosity than a similar addition of the spherical glass beads. The viscosity of the emulsion/solids mixtures was influenced by the solids size as well; the smaller size particles gave a higher viscosity. The addition of solids to the bitumen emulsions also induced shear thickening (dilatancy) behavior at high solids volume fraction. The degree of the shear thickening increased with the oil concentration.     

Pickup (critical) velocity of particles

This work presents experimental results on pickup velocity (critical velocity) measurements for a variety of particulate solids. The present experiments together with previously published experiments of a number of researchers encompass about 100 measurements of 24 materials for a wide range of particle sizes, shapes and densities. Based on the experimental results, three zones are defined by establishing simple relationships between the Reynolds and Archimedes numbers. The empirical relationships were further modified by taking into account the pipe diameter and particle shape (sphericity). The three-zone model was shown to reasonably correlate to Geldart's classification groups.     

基于概念设计阶段的解耦模式车门截面形状优化方法

为了提高车门静态刚度, 采用基于HDMR理论的多参数解耦优化方法与Morph技术结合, 对一款处于概念设计阶段车门的主截面形状进行优化。这种建模方法的特点在于通过少量的样本点识别形状变量之间的耦合关系, 进而将高维问题进行分解, 在保证精度的前提下提高计算效率。采用Kriging插值方法对Cut-HDMR的各项进行构造, 得到车门各刚度下的考察点位移和质量的近似模型, 进而利用非支配排序多目标遗传算法（NSGA-Ⅱ）对近似模型进行优化, 在车门静态刚度均达到设计要求的前提下合理进行减重, 使垂直刚度和扭转刚度得到了很大的提高。     

Measurement of the size, shape and orientation of convex bodies

Different types of solid bodies (particles) with specific shape and size are needed for industrial processes. For spherical particles, ‘sizer’ measurements are usually reported as sphere diameters. For non-spherical particles, particle shape and especially orientation must be taken into account. Particles of a specific shape will present different views when looked at from different directions.We have employed a Camsizer^® instrument to measure the distribution of projected area under different physical conditions for solid cylindrical particles:

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Under ‘ideal’ conditions, corresponding to a uniform distribution of particle orientation, measurements agreed with predictions. The celebrated theorem of Cauchy applies only to this case.

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For two other situations, measured and predicted results differed. However, from the experimental data it was possible to infer the particle orientations and hence theoretically predict the projected area distribution. Excellent agreement between theory and practice was then restored.

     

基于环形微热板的ZnO微气体传感器设计

提出一种新型的设有环形结构微热板的硅基ZnO微气体传感器。利用ANSYS软件,将环形电极结构与传统的蛇形结构进行温度分布的模拟仿真,发现该结构能供给传感器更高的温度且中心温度分布均匀,进而解决了现有传感器功耗大的缺点。通过对RF磁控溅射ZnO薄膜的工艺摸索,得出了适宜作气敏薄膜的制备参数。该传感器在250℃下对（200-1000）×10-6CH4气体有很好的响应。