AFM study for morphological characteristics and biomechanical properties of human cataract anterior lens capsules

The aim of this study was to quantitatively investigate the morphologies (surface roughness) and biomechanical properties (Young's modulus) of human anterior lens capsules (ALCs) for noncataract and cataract groups using atomic force microscopy. Eight human ALCs obtained during phacoemulsification from patients with senile cataracts (72 ± 13 years) were investigated in both the hydrated and dehydrated conditions. The cataract group showed clearly the proliferated lens epithelial cells (LECs) with a monomorphic cell structure, a diameter of 12.54 ± 4.31 μm, and a height of 0.23 ± 0.04 μm, whereas the control group showed no LECs. A substantial amount of false-positive calcification was observed caused by the deposition of remnants of dried salt solution. Cataract group showed significantly higher surface roughness (382.06 nm, p ≤ 0.001) than control group in the anterior side of ALCs, whereas cataract group showed significantly lower surface roughness (353.79 nm, p ≤ 0.001) than control group in their posterior side. Cataract group showed significantly higher Young's modulus (69.52 kPa, p ≤ 0.001) compared to the control group, regardless of the ALC side. Therefore, it is significant that this study provides a new method to examine the nanostructural characteristic and biomechanical property of human ALCs through a nanometer-scale resolution microscopy technique.     

超弹性蒙皮蜂窝芯的设计及等效模量研究

可变形机翼的蒙皮需要有很高的各向异性,在特定方向具有较低的弹性模量而在其他方向具有较高的气动承载能力,为此设计了一种柔韧性较好、特定方向模量低且承载能力较强的新型超弹性蒙皮结构,对其蜂窝芯单元的力学性能进行了理论计算和有限元分析,并对不同几何参数单个蜂窝芯单元体和多个蜂窝芯单元体进行了轴向刚度测定试验,最后通过理论仿真和试验的对比分析,得到了该超弹性蒙皮蜂窝芯结构轴向刚度的等效模量近似工程计算公式。
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油液体积弹性模量的测量

液压油的体积弹性模量是影响液压统动态分析、建模与仿真正确性的主要参数之一。本文对油中含气量、油压、油液温度、容器刚度以及油与空气的接触情况等因素的分析,对油液体积弹性模量的测量进行了研究。     

原子力显微镜测量双光子成型点的弹性模量

提出了一种飞秒激光双光子成型点弹性模量的测量及结果分析方法.借助于原子力显微镜,选用无针尖探针对成型点的力学性能进行了测试,建立了椭球-平面接触的弹性力学模型.考虑了成型点剩余部分形变对结果分析的影响,在标定微探针弹性系数和对粘附力进行分析的基础上,提取了力曲线中所包含的力学信息,推算出了成型点的弹性模量,得到了成型点的弹性模量低于宏观材料弹性模量的结论.     

A multiscale mechanics approach for modeling textured polycrystalline thin films with nanothickness

A multiscale method is proposed for calculating elastic constants of textured polycrystalline thin films of nanothicknesses. In this method the molecular simulation and finite element method are hierarchically employed. The elastic constants for each single crystal are first calculated through the simulations of on- and off-axis tension tests of the single crystal using molecular statics. Subsequently, the constitutive relations for the single crystal are used in conjunction with a finite element code to study the macro-mechanical deformation and stresses in textured polycrystalline nanofilms. The result indicates that both film thickness and grain size influence the macro-Young's modulus and Poisson's ratio of the nanofilm. Specifically, for nickel, the value of the macro-Young's modulus decreases as film thickness decreases and increases as grain size decreases. The value of the macro-in-plane Poisson's ratio increases as the thickness decreases or grain size increases.     

溶胶—凝胶工艺制备Al2O3-ZrO2涂层对工程陶瓷表面改性的研究

采用溶胶－凝胶工艺在SG4氧化铝基工程陶瓷上成功制备了Al2O3-ZrO2 涂层。利用差热分析（DTA）、扫描电子显微镜（SEM）、X射线衍射（XRD）等分析手段对Al2O3-ZrO2涂层的物相组成、表面和断面形貌进行了表征。分别对精磨、热处理、Al2O3-ZrO2涂层试样的抗弯强度和Weibull模数进行了比较。结果表明：Al2O3-ZrO2涂层可明显改善工程陶瓷的表面质量;涂层与基体结合紧密,无明显界面层;涂层试样的抗弯强度和Weibull模数均比未涂层试样显著提高。     

一种硬盘基板用新材料——微晶玻璃

微晶玻璃是一种在计算机硬盘基板应用方面很有潜力的新型材料,对某厂研制的Li2O·2SiO系硬盘基板用微晶玻璃的力学性能进行了测试,对结果的分布状况进行了统计分析。结果表明:与传统的铝合金材料相比,该材料具有较高的抗弯强度、弯曲弹性模量和维氏硬度;其结果均符合Weibull分布,Weibull模数的最小二乘估计值较高,表明该材料强度分布的离散性小,使用安全可靠性高。     

高分子材料弹性模量、泊松系数、切变模的测试

本文报道了以应变电测原理和技术测试某公司新研制的高分子材料的弹性模量、泊松比、切变模量的结果。并对试验方法及电阻应变片的迭取及贴片工艺进行了分析和讨论。     

Shear Strength of Pressure Sensitive Adhesives and its Correlation to Mechanical Properties

Correlations between shear resistance and the mechanical properties of pressure sensitive adhesives are studied by measuring the deformation behaviour in the static and the dynamic shear test and determining the dynamic shear modulus of the adhesive. For polymers with low or moderate viscosities, the shear strain vs. time characteristics in a static shear test and, accordingly, the static shear strength, can be evaluated from the master curves of the dynamic shear modulus or the dynamic viscosity. The dynamic shear strength also can be calculated. These exact calculations cannot be applied to highly viscous or slightly crosslinked polymers. On the basis of the model experiments, empirical correlations between shear strength and the dynamic shear modulus are established which seem to be generally valid.     

旋转机组的基于变权重神经网络组合预测模型

面向旋转机组工作状态的趋势预测，结合组合预测模型和人工神经网络预测模型的各自优点，提出了一种变权重神经网络组合预测模型的新方法。该方法是变权重神经网络的非线性映射能力，依据各单项预测模型对预测结果的不同影响。动态确定组合预测模型的权系数。在大型旋转机组工业现场应用中，采用这种模型进行预测提高了预测精度，获得较好的预测效果。