Small Deflection Problem of Polar Material Spiral Laminates

This paper discusses the effect of spiral laminae of polar materials on the stiffness of laminates and gives out the relation between spiral angle and equivalent elastic constants of the spiral laminates including asymmetric stresses and coupled stresses.It is concluded that the appropriate choice of the spiral angle of laminae can greatly enhance the stiffness of laminates.     

从应变能导出刚度矩阵

结构矩阵分析(Matrix Structufal Analysis)是随着电子计算机的出现而发展起来的一种结构分析方法,其特点是在分析计算时将各类型载荷时结构的作用以不向的刚度矩阵(Stiffness Matrices)来表示.刚度矩阵可用 FORTRAN 语言编成电算程序并储存起来,对结构分析带来极大的方便。刚度矩阵的计算方法一般采用微分方程的近似解、Castigliano 法和虚位移原理等。本文作者提出“从应变能导出刚度矩阵”,推导过程严谨,易于理解和接受。     

葡萄与番茄宏观力学特性参数的确定

通过对葡萄与番茄的压缩试验，测得其力—位移曲线，得出在相同加载速率下，不同硬度的葡萄与番茄在横、纵向压缩时的力学特性及刚度与变形之间的关系。并对果皮进行了横、纵向的拉伸试验，得到了皮的弹性模量与应变之间的关系，确定了以果品表皮破裂作为机械损伤的形式，用果皮的破坏强度衡量葡萄与番茄的损伤,为建立葡萄与番茄的力学模型及设计有关的机械设备提供力学参数。     

高层主楼与裙房间基础处理

本文主要论述了在高层建筑中不设沉降缝而对高层主体与裙房之间进行的设计与构造处理。     

Correlation of serum uric acid level with carotid plaques and arterial stiffness in patients with essential hypertension

AIM：To study the correlation of serum uric acid (UA) level with carotid plaques and arterial stiffness in the patients with essential hypertension (EH), and to explore the predictive value of serum UA for evaluating EH preclinically. METHODS：A total of 92 patients with EH and 30 healthy individuals were enrolled. The value of UA and other indicators were detected. B-mode ultrasound examination was performed to measure the common carotid artery intima-media thickness (IMT) and the sites of plaque in the internal carotid-artery, external carotid artery and carotid bifurcations. Carotid-femoral arterial pulse wave velocity (CFPWV) was assessed by Complior atherosclerosis measurement instrument. RESULTS：The serum level of UA in the patients with EH was higher than that in control group ［(361.51±83.81） μmol/L vs (317.03±62.22) μmol/L, P<0.05］. The mean value and abnormal rate of IMT between hypertension group and control group were significant difference ［(0.69±0.14) mm vs (0.60±0.12) mm, 42.39% vs 10.00%, P<0.05］. In 92 EH patients, 45 cases had carotid plaques. These 45 cases were divided into 3 groups according to the plaque severity, among which the serum UA level had statistically significant differences ［(285.25±78.41） μmol/L, （341.19±63.99） μmol/L and （401.33±88.49） μmol/L, P< 0.05］. Compared with rigid plaque group (n=34), the serum UA level in soft plaque group (n=11) was significantly higher ［(389.00±69.45) μmol/L vs （323.03±72.71） μmol/L, P<0.05］. A stepwise multiple linear regression analysis demonstrated that age (r=0.414), systolic blood pressure (r=0.224), pulse pressure (r=0.270) and uric acid (r=0.219) were predisposed factors for higher CFPWV (P<0.05). CONCLUSION：UA is one of the risk factors causing hypertension. Serum UA level may reflect the severity and stability of carotid plaques. The increased arterial stiffness is closely related to the increased serum UA level in EH.     

A novel movement disorder in related male Labrador Retrievers characterized by extreme generalized muscular stiffness

Objectives: To describe the clinical phenotype of a new motor disorder in Labrador Retrievers. Animals and Methods: Case series study. Seven young male Labrador Retrievers presented for evaluation of stiff gait. Results: All affected dogs had generalized muscular stiffness, persistent at rest and resulting in restricted joint movements. They showed a forward flexed posture, festinating gait, and bradykinesia. Signs developed between 2 and 16 months of age and tended to stabilize in adulthood. Needle electromyogram in the conscious state showed continuous motor unit activity in resting epaxial and proximal limb muscles. This activity was abolished by general anesthesia. Muscle and nerve histopathology was normal. In 2 dogs necropsied, astrocytosis was evident throughout the spinal cord gray matter, reticular formation and caudate nuclei. Decreased neuronal counts were selectively found in the spinal cord Rexed's lamina VII, but not in VIII and IX. Pedigree analysis showed that the affected dogs were from 5 related litters. Conclusions and Clinical Importance: This new hypertonicity syndrome in Labrador Retrievers is unique because of the selective distribution of the histological lesions, the lack of progression in adulthood, and its exclusive occurrence in male dogs. Pedigree analysis suggests an X‐linked hereditary disease, although other modes of inheritance cannot be ruled out with certainty. We hypothesize that altered output from basal nuclei and reticular formation together with motor neuron disinhibition caused by a decreased number of spinal cord interneurons leads to the muscular stiffness.     

隔震结构复位弹簧刚度的敏感性分析

摩擦滑移隔震技术是开发应用最早的基底隔震技术之一。本文通过一个算例，对复位弹簧的刚度对隔震结构的隔震效果的影响作了定量分析，并给出了复位弹簧刚度选取的参考性建议。     

Simple Shear Test of Interface between Sand and Structure under High Stress

By using a simple shear apparatus that is developed from RMT-150B,a series of simple shear tests of interface between saturated sand and structure under high normal stress were carried out to study constitutive law and shearing stiffness of interface to provide some theoretical evidences for design and calculation of projects concerned with mechanical problem of interface.In test,sand was consolidated in upper shearing box firstly,then,shear was started and testing data was recorded under high and constant normal stress.During the process,sand can deform relatively freely.It is shown that the relation curve between shear stress and shear displacement under high normal stress in simple shear tests is different from that in direct shear tests,and the complete shearing deformation process of interface under high stress can be described as a nonlinear elastic-perfect plastic form;Weibull distribution with three parameters can overcome the mathematical deficiencies of hyperbola in NEPP.The new model which is established by substituting Weibull distribution for the hyperbola of NEPP better agrees with the testing data.The regressive results of the initial shearing stiffness demonstrate that the linear function is slightly better than power function to express the relation between the initial shearing stiffness and normal stress.Based on the new interface model,the formula of tangential shearing stiffness is proposed,meantime,the change trend of tangential shearing stiffness of the new model is compared with that of NEPP.     

Experimental Analysis of Rotational Behavior of Timber Beam-column Connection of Ancient Tibetan Architecture

Static experiment was carried out to study rotation behavior of timber beam-column connection. The influence of length of Gongmu and position of dowel on the initial rotational stiffness of the joint was analyzed. Rules of stiffness degradation under cyclic loading were studied as well. The results show that: the moment-rotation curve of typical timber beam-column connection can be simplified as bilinear model; the initial rotational stiffness of the joint is enhanced with the increase of the length of Gongmu, and it is decreased with the inward movement of dowel; under the same conditions, the influence of the inward movement of Gongmu-beam dowel on the initial rotational stiffness of the joint is smaller than that of Dianmu-Gongmu dowel; and stiffness degrades under cyclic loading and there exists obvious transition phenomenon.