大跨度RC天桥施工全过程的力学分析

利用有限单元法,研究澳门某学校建筑的大跨度行人天桥在混凝土施工过程中,出现的不正常挠度,导致天桥底模板支撑发生失稳压弯破坏严重事故,事件的发生并非直接由外来荷载的扰动所引起,而是由于天桥结构内部不同浇灌龄期混凝土强度,刚度的发展,引致桥体发生内力重分布,这种内力重分布使天桥墙体底部某些模板支撑的反力增大,导致原来已因设置数量不足而接近失稳临界状态的天桥底模支撑,发生了屈曲破坏,文中对这种施工暂态结构的力学特性进行了探讨。     

Generalized Riccati equation expansion method and its application to the Bogoyavlenskii's generalized breaking soliton equation

Based on the computerized symbolic system Maple and a Riccati equation, a Riccati equation expansion method is presented by a general ansatz. Compared with most of the existing tanh methods, the extended tanh-function method, the modified extended tanh-function method and generalized hyperbolic-function method, the proposed method is more powerful. By use of the method, we not only can successfully recover the previously known formal solutions but also construct new and more general formal solutions for some nonlinear differential equations. Making use of the method, we study the Bogoyavlenskii's generalized breaking soliton equation and obtain rich new families of the exact solutions, including the non-travelling wave and coefficient functions' soliton-like solutions, singular soliton-like solutions, periodic form solutions.     

二维复空间型的全实曲面

主要利用函数f(x)=maxu,v∈UxM||B(u,u)-B(v,v)||^2研究具有平行平均曲率向量的二维复空间型的全实曲面,并得到关于全脐点子流形的Pinching定理。     

单一弱面控制岩石力学系统特性

在含有面的岩石微元体中,弱面的倾角不同,岩石力学系统的结构形式就不同,其力学特性随着弱面倾角的变化而变化;弱面的力学参数的变化也是控制整个岩石微元体力学性能的主要因素。弱面的粘聚力越大,微元体系统承能力越大,并且承载能力随弱面内摩擦系数的增大而增加。     

反无穷维Hamilton系统的反问题

给出了把守恒定律形式的方程组化成等价的反Ｈａｍｉｌｔｏｎ方程的充要条件,并列举了几个应用的例子。     

相对论性Birkhoff方程的几何理论

定义相对论性Pfaff作用量 ,给出相对论性Pfaff_Birkhoff原理和相对论性Birkhoff方程 ,研究相对论性Birkhoff方程的几何描述 ,给出相对论性Birkhoff方程的恰当特性以及相对论性Birkhoff方程在R×T M上的形式 .研究相对论性Birkhoff方程的全局处理 ,给出自治形式、半自治形式以及一般形式的相对论性Birkhoff方程的全局特性 ,并给出相对论性Birkhoff方程的能量变化的几何特性 .     

一种近似恒力弹簧装置的设计

为消除弹簧装置中应力随应变不断变化而产生的多余应力 ,在卷簧结构中 ,采用螺旋变径输出轮 ,用半径的变化抵消力矩的变化 ,获得近似恒定的输出力 .在精度要求不高的场合 ,采用此方式可形成简便可靠的近似恒力的弹簧装置 .     

钴的添加形式对氢氧化镍电极性能的影响

研究了钴元素分别以Co ,CoO ,Co +CoO三种形式作为添加剂并分别以与Ni(OH) 2 用机械混合的方式添加到电极活性物质中时对镍电极性能的影响 ,用循环伏安法和电化学交流阻抗法对实验结果进行分析 .结果表明 :对于机械混合的添加方式 ,Co ,CoO和Co +CoO三种形式的钴添加剂均可在一定程度上改善镍电极的性能 .其中 ,当钴以CoO的形式添加时镍电极的性能最好 .这是因为三种形式的添加剂均在一定程度上改善了活性物质Ni(OH) 2 的结构、增强了电极中质子的传输能力 ,从而提高了镍电极反应的可逆性 ,强化了镍电极的析氧极化 ,并提高了镍电极的充电效率 ,其中CoO的作用效果最明显 .     

Thermogravimetric Study of Carbonization Processes for Industrial Porous Co-polymers of Spherical Granules

The industrial porous co-polymers and resins in the form of spherical granules include three main matrices which serve as the basis of the large-scale production of ion-exchange materials: styrene/divinylbenzene, vinylpyridine/divinylbenzene and acrylonitrile/divinylbenzene. Complex thermal methods (TG, DTG and DTA) were used to study the carbonization processes of various industrial products utilized as starting materials for the preparation of synthetic active carbons. The DTG results, the thermal effects observed during the programmed heating of samples, and the mass-spectrometric and IR-spectroscopic data up to 800°C provided a picture of a multi-stage carbonization process. This includes the removal of moisture from the polymer matrices, the primary cross-linking of the chains, their aromatization and condensation due to the cross-linking of polynuclear structures, and the removal of ‘excess carbon’ as simple molecules and free radicals of hydrocarbon type. The results promoted the choice of the optimal regimes in which to carryout the isothermal pyrolysis of various polymer matrices and preliminary chemical modifications to increase the yields on carbon and to prepare synthetic active carbons such as those of SCN, SCAN and SCS types. General schemes were proposed for the chemical reactions accompanying the carbonization process for these polymer matrices. This revised version was published online in August 2006 with corrections to the Cover Date.     

Metacyclic groups and modular forms

In the paper we find the metacyclic groups of the form 〈a, b:a ^m=e, b ^s=e, b ⁻¹ ab=a ^r〉, wherem=3, 4, 5, 7, 11, 23, such that the modular forms associated with all elements of these groups by some faithful representation are multiplicative η-products. Translated fromMatematicheskie Zametki, Vol. 67, No. 2, pp. 163–173, February, 2000.