Polymeric Tubular Aromatic Amide Helices

Conjugated polymers may be induced by intra‐ and/or intermolecular non‐covalent forces to fold into helical conformations. Helices formed by aromatic amide, hydrazide, and urea polymers possess a well‐organized cavity and depth, which is defined by their degree of polymerization. Driving forces may be intramolecular hydrogen bonding and/or solvophobicity, or guest induction. The resulting long helices represent a new class of unimacromolecular dynamic tubular architectures that exhibit unique properties or functions in, for example, molecular recognition, chirality transfer, and ion transporting. The recent advances are highlighted here.

     

Thermal-mechanical behavior of styrene-based shape memory polymer tubes

Styrene-based shape memory polymer (SMP) tubes were fabricated and their basic mechanical properties in different deformation states were investigated. The tensile, compression, bending and twisting shape memory properties of the tubes were analyzed and discussed, and the results indicated that SMP tubes exhibit good shape fixity ratio and shape recovery ratio. In addition, the shape recovery behavior was investigated at different heating rates. These experimental results will provide guidance for future applications of SMP tube structures.     

PLASTIC BUCKLING OF STIFFENED TORISPHERICAL SHELL

ＰＬＡＳＴＩＣＢＵＣＫＬＩＮＧＯＦＳＴＩＦＦＥＮＥＤＴＯＲＩＳＰＨＥＲＩＣＡＬＳＨＥＬＬＨａｏＧａｎｇ（郝刚）ＺｅｎｇＧｕａｎｇｗｕ（曾广武）ＨａｏＱｉａｎｇ（郝强）（ＲｅｃｅｉｖｅｄＤｅｃ．３０，１９９４．ＣｏｍｍｕｎｉｃａｔｅｄｂｙＰａｎＬｉｚｈ...     

剪切载荷下肋板的屈曲分析与优化

利用ANSYS有限元方法分析了一系列的肋板，研究了加强肋的作用，提出了 优化肋设计的限制条件. 结果表明，由横向肋板产生的栅格数目不能小于肋板的长宽比. 换 句话说，横向加强肋必须把平板的长度划分为小于等于宽度的段. 结果还显示，加强肋的优 化几何特性与板的屈曲从整体模态到局部模态转变点相应. 而且，所有具有相似长宽比和肋 数的肋板，具有一个特定的比值$EI_{s}/aD$, 此时抗剪应力最佳.     

后负荷对心室压力—容积关系的影响

本文利用一种心室分析模型，对心室后负荷，用更符合循环生理实际的非对称Ｔ型管模型替代三元件的Ｗｅｓｔｅｒｈｏｆ模型，在此基础上研究心室压力－容积关系随后负荷的变化情况发现收缩末期的心室压力－容积关系基本上不随后负荷的改变而改变。     

Turbulent flow of mildly elastic fluids through rotating straight circular tubes

The turbulent flow of mildly elastic drag reducing fluids through a straight tube rotating around an axis perpendicular to its own is analysed using boundary layer approximations. The momentum integral approach is used and the governing equations have been solved numerically using the Runge-Kutta-Merson method. The influence of the Deborah number on the velocity distribution and the boundary layer thickness has been exemplified through the analysis. NCL Communication No. 3354.     

Improved general correlation for critical heat flux during upflow in uniformly heated vertical tubes

An improved version of the author's earlier correlation for CHF in vertical tubes is presented. It is compared with data that include 23 fluids (water, refrigerants, cryogens, chemicals, and liquid metals), tube diameters 0.315 to 37.5 mm, tube length 1.3 to 940 times diameter, mass flux 4 to 29051 kg/m²s, reduced pressures 0.0014 to 0.96, inlet quality −4 to +0.85, and critical quality −2.6 to +1. These data, from 62 independent sources, are also compared with Katto's general correlation and those of Bowring for water and Subbotin for helium. The present correlation shows much better agreement with data.     

软管流量调节器调节特性分析及设计准则

分析了大雷诺数下软管的流量调节行为；导出了流量随下游压力的函数关系，即流量调节特性曲线；提出了以软管作为能动元件的流量调节器设计准则．     

投影云纹法在研究加劲板后屈曲平衡路径及后屈曲模态转化过程的应用

本文应用投影云纹法研究受压加劲板的大挠度非线性问题。用投影云纹法测量加劲板后屈曲平衡路径,记录了随着载荷的增加,加劲板后屈曲模态变化的全过程。将云纹图输入微型计算机处理,获得了加劲板的全场位移和全场应力的分布情况。用投影云纹法所测得的结果同理论计算值基本吻合。