浅谈高层建筑结构位移控制

介绍了规范对高层建筑结构设计位移控制的规定,论述了高层建筑层间位移角、剪切变形等的相互关系,以使高层建筑结构层间位移控制满足规范要求,保证高层建筑必要的刚度。     

Preparation and functional properties of protein coprecipitate from sheep milk

The optimum conditions for the production of coprecipitate from sheep milk were studied. The best percentage of calcium chloride added to milk was 0.2%, which resulted in a recovery of 97.5% of milk proteins. At low pH (4.5–5), the recovery of protein was low, but it increased at higher pH values (5.5–6.5); recovery was greatest at pH 6.5. The optimum heating temperature to obtain coprecipitate from sheep milk was 85–95°C. The functional properties of the sheep milk coprecipitate were studied. At pH values higher than 6, there were no differences between the solubility of sheep milk coprecipitate and sheep milk sodium caseinate, but the solubility of coprecipitate at pH values lower than 5 was relatively higher than those of the caseinate. At pH ≥6, the emulsion activity index (EAI) for emulsions of sheep milk coprecipitate and caseinate increased as pH increased; at all pH values, the EAI of the coprecipitate was higher than that of the caseinate. Sheep milk coprecipitate showed higher foaming ability and stability than sheep milk sodium caseinate.     

新型剪断撑顶二合一破障装置的设计

现有的剪断撑顶二合一破障装置大都过于笨重,适用范围较小。新型剪断支顶二合一破障器小巧轻盈,便于携带,能轻易对单根、多根钢筋进行剪断,并能将障碍物进行扩张,扩张行程20～800 mm,大大提高了破障效率。介绍了该新型破障装置的原理和结构特点,并对关键零件活塞杆、刀具和钢筒进行了强度校核。     

INFLUENCES OF HEAT-TREATING PROCESS ON DUCTILE FRACTURE MECHANISM UNDER MIXED MODE LOADINGS

１ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｅｎｇｉｎｅｅｒｉｎｇｐｒａｃｔｉｃｅ，ａｌｏｔｏｆｃｒａｃｋｐｒｏｂｌｅｍｓｃａｎｂｅｉｎｃｌｕｄｅｄｉｎｄｉｆｅｒｅｎｔｃｏｍｂｉｎａｔｉｏｎｓｏｆｔｈｒｅｅｂａｓｉｃｆｒａｃｔｕｒｅｍｏｄｅｓ，ｉ．ｅ．ｍｉｘｅｄ...     

Increased Prostaglandin Response to Oxytocin in Ewes Fed a Diet High in Omega-6 Polyunsaturated Fatty Acids

Diets high in omega-6 polyunsaturated fatty acids (n-6) are associated with increased prostaglandin F_2α (PGF_2α) synthesis in cattle, however, the specific effects on the potential prostaglandin response to an oxytocin challenge in sheep have not been reported. The aim of the current study was to determine whether oxytocin-stimulated PGF_2α was significantly increased when ewes were fed a diet high in n-6 compared with a control diet low in n-6. Merino x Border Leicester ewes (n = 30) received one of two dietary treatments, either high in n-6 (70 % oat grain) or low in n-6 (control diet, 100 % cereal/legume silage). Ewes consumed the diets for 44 days prior to two consecutive oxytocin challenges. Plasma n-6 and PGF_2α metabolite (PGFM) concentrations following oxytocin challenge were greater (P < 0.05) when ewes were fed a diet high in n-6 compared with the control diet. A higher availability of n-6 may have lead to an increased in vivo synthesis of PGF_2α, however, further research is required to determine the exact mechanisms involved.     

细粒尾矿砂加筋增强效果实验研究

以四川某矿山企业在选矿过程中产生的细粒尾矿为材料，通过室内实验对其加筋增强效果进行了研究，并根据实验结果提出了影响细粒尾矿力学特性的最优加筋密度，研究成果对细粒尾矿加筋力学性能分析具有重要的参考价值。     

承受k/r型剪应力作用楔形体问题的应力解

对非对称楔形体在楔面承受各种不同荷载作用下的弹性应力解进行了比较系统的研究．首先利用应力函数及其导数在楔形体边界上的力学意义和海维赛（Ｈｅａｖｉｓｉｄｅ）函数，求出了在楔面下部承受ｋ／ｒ型剪应力作用下非对称楔形体问题的弹性应力的一般解，然后，令楔面角α和β取不同的值，可以得到各种不同问题的弹性应力解，如边坡问题和１／４平面问题的弹性应力解．其结果可为实际工程问题提供理论依据．     

弹性约束半空间内浅埋圆孔对SH波的散射

利用复变函数法和多极坐标移动技术求解讨论弹性约束边界半空间内浅埋圆孔对稳态入射平面SH(shearing horizontal,反平面剪切)波的散射问题.为了克服直接构造波函数场的困难,采用一个半径很大的圆孔边界来拟合半空间的直边界,因而原来问题即转化为无限大空间内大圆孔和小圆孔对入射平面SH波的散射问题.文中具体讨论小圆孔边界处的动应力集中系数随无量纲波数、入射波入射角的变化情况,算例结果表明文中处理方法是合理的.     

Measurement of interfacial fracture parameters using coherent gradient sensing (CGS)

An optical interferometry called coherent gradient sensing (CGS) has been extended for mapping interface crack tip fields and for evaluating fracture parameters. The optical technique is a double grating shearing interferometer with an on line spatial filtering arrangement. The method offers real time full field measurements and can be used both in transmission made and reflection mode. The interferometer measures small angular deflections of light rays which can be further related to in plane gradients of _x + _y in transmission through elasto-optic relations. Direct interfacial crack tip measurements in a high stiffness mismatch PMMA-aluminium bimaterial system are performed. A variety of crack tip mode mixities are studied using asymmetric four point bend specimens subjected to different far field mechanical loads. The. complex stress intensity factors and the associated phase angles are measured from CGS patterns using an asymptotic expansion field. The measurements are compared with finite element results.     

工业厂房中混凝土吊车梁的设计

通过实例,分析在旧有厂房中增设混凝土吊车梁的可行性和解决途径,探讨带混凝土吊车梁结构在设计时应控制的因素;介绍了利用现有的电算程序与通用文献,进行吊车梁快速设计的方法。