各向异性材料的表面张力

本文提出一种能够统一处理各向异性表面张力的张量描述方法。通过引入表面张力张量,导出表面有关物理量和表面平衡条件,并根据材料对称性,分别对单轴液晶、双轴液晶和晶态固体的表面张力作了讨论,还给出了单轴液晶自由表面平衡的完整条件。     

圆柱形非互易旋电手征波导中模色散和衰减特性

本文研究了圆柱形非互易旋电手征波导中混合模的传输特性。在这种复杂导波结构中，由于各向异性、非互易和手征参数的引入，使得它具有某种新奇的特性。用数值方法分析了低阶和高阶混合模的模分裂和衰减特性，并且考虑了非互易和手征参数对截止频率的影响。     

磁组构与花岗岩基的形变

用花岗岩基的磁组构特征研究了滇西临沧岩石的形变特征，研究表明，临沧花岗岩基从西向东由磁化率各向同性向各向异性过渡，且各向异性度逐渐增大，磁组构的ａ轴和ａｂ面走向从西向东由近东西向逐渐转变为近南北向。磁组构具有研究花岗岩构造的可行性，可以反映花岗岩基整体构造的形变特征，由此揭示了岩基中西部弱变形的东西向构造与东部边界强变形剪切带的近南北向构造。     

含有椭圆孔的各向异性体平面问题的通解

应用复变函数方法,给出了在椭圆孔外任一点作用任意一个集中力和集中力偶时的Green应力函数,即应力函数基本解.通过基本解的迭加,首次得到了在椭圆孔周围作用任意集中载荷或分布载荷时表达简洁的通解.为了验证该解的正确性并说明其应用,给出了当孔周作用一对平衡的集中力或均匀的分布力时的解,其结果与前人所得的结果一致.     

Anisotropy of nickel-based superalloy K418 fabricated by selective laser melting

Selective laser melting (SLM) is a promising additive manufacturing (AM) technology for fabricating the near net-shaped parts by selectively melting and solidifying a thin powder layer with a high-intensity laser beam according to the CAD data for arbitrary components. In this work, Ni-based superalloy K418 samples were fabricated by selective laser melting (SLM). To evaluate the anisotropic mechanical behavior of the SLM processed K418 samples with layer-by-layer melting, the samples were manufactured parallel (transverse specimens) and vertical (longitudinal specimens) to the building direction on the substrate. The microstructural anisotropy analysis was performed by optical microscopy (OM) and scanning electron microscopy (SEM). Electron backscatter diffraction (EBSD) analysis was used to identify their crystallographic preferred orientation (texture) and to correlate the anisotropy of the mechanical strength with the texture of the material. The results showed that the transverse specimens had slightly higher yield strength, but much significantly higher ductility than that of the transverse specimens with the elongated columnar grains along the building direction.     

各向异性层合阻尼材料的模态应变能分析

将大型有限元软件ANSYS10．0引入到各向异性层合阻尼材料的结构分析中,应用基于应变能的模态分析方法研究了各向异性层合阻尼材料的固有频率和总应变能分布随材料主控参数的变化情况,为进一步分析各向异性层合阻尼结构的阻尼性能奠定基础。分析结果表明：主控层第5层的纤维铺设角度和第2层的铺层厚度分别取90°和0．5mm时试件的结构损耗性能最优。     

磁晶各向异性下铁磁体的线性与非线性磁化和磁化率

铁磁体的磁化率是研究铁磁体系动力学的基础．研究磁晶的各向异性对磁化率,尤其是非线性磁化率的影响有重要意义．本文首次推导了磁晶各向异性下铁磁体的线性与非线性磁化和磁化率,讨论了立方各向异性和单轴各向异性两种典型情况,结果表明磁晶各向异性对铁磁体的磁化和磁化率有贡献,对三阶非线性磁化和磁化率影响明显．     

向异性材料弹性矩阵的变换矩阵

本文给出了各向异性材料弹性性质的变换矩阵的一般形式，成为对各向异性材料有限元分析不可缺少的工具     

How to tell causes from effects: Kant’s causal theory of time and modern approaches

I attempt a reconstruction of Kant’s version of the causal theory of time that makes it appear coherent. Two problems are at issue. The first concerns Kant’s reference to reciprocal causal influence for characterizing simultaneity. This approach is criticized by pointing out that Kant’s procedure involves simultaneous counterdirected processes—which seems to run into circularity. The problem can be defused by drawing on instantaneous processes such as the propagation of gravitation in Newtonian mechanics. Another charge of circularity against Kant’s causal theory was leveled by Schopenhauer. His objection was that Kant’s approach is invalidated by the failure to deliver non-temporal criteria for distinguishing between causes and effects. I try to show that the modern causal account has made important progress toward a successful resolution of this difficulty. The fork asymmetry, as based on Reichenbach’s principle of the common cause, provides a means for the distinction between cause and effect that is not based on temporal order (if some preconditions are realized).     

2,3-二氯对苯二酚酯类负性液晶的合成和性能研究

设计合成了新的负性液晶双—(对烷基苯甲酸)—2,3—二氯—1,4—苯二酚酯类化合物,其结构为这里R·CH_3,C_2H_3,n—C_4H_9和n—C_7H_(15).合成了相应的一些中间体,测定了液晶的相变温度和相态,通过磁场法,测定了R=CH2的介电各向异性.