The Effect of Adherends on the Curing of an Epoxy Adhesive

The effect of E-glass, cured vinyl ester resin, and silica gel on the curing of an epoxy-anhydride adhesive was examined. The techniques used were calorimetry in both isothermal and scanning modes and Fourier transform infrared spectroscopy in the attenuated total reflectance (ATR-FTIR) mode. Isothermal calorimetry was used to obtain the exotherm, conversion rate, and curing kinetic parameters, and scanning calorimetry was used to obtain the glass transition temperature. ATR-FTIR was used to study the curing kinetics and chemistry of the adhesive. The results suggest either the immobilization of a layer of the epoxy adhesive adjacent to inert solid surfaces or selective adsorption of the accelerator or both, each of which suppresses the cure reaction. This was reversed by the presence of adsorbed water. At least for this epoxy-anhydride system, adsorbed water seems to have had the beneficial effect of increasing the crosslink density in the interfacial region between the adhesive and adherend. Water seems also to change the overall cure reaction, causing more ether formation and less ester formation than without water. An additional finding was that the cured vinyl ester surface appeared to have a catalytic effect on the reaction, perhaps in conjunction with the accelerator, benzyldimethylamine.     

大时滞不稳定对象的PID控制

对一阶大时滞不稳定对象的控制，普通的PID控制器很难满足要求，有时甚至无法实现系统的稳定。采用了双环控制结构，先构造内环状态反馈以改善对象动态特性，然后按照内模控制原理设计外环的控制器。仿真结果表明了该方法的有效性。     

Effects of Large-Scale Twin Tunnel Excavation on an Existing Pile Group: Three-Dimensional Centrifuge Modeling

Soil Mechanics and Foundation Engineering - Existing piles are commonly encountered during tunnel construction in congested underground areas. Tunnel-soil-pile interaction has recently attracted...     

城市环境敏感地段的“建筑·交通一体化”设计策略初探

城市中的大型建设项目往往处于重要交通节点或多种功能高密度集中的地段,此类地段可称为"环境敏感地段"。在地段内进行建设项目的设计与评价时,需要将"交通"作为内在要素之一纳入建筑设计的范畴综合考虑,实现建筑与步行、轨道、机动车等多种交通系统的整合。以提升城市品质为目标,提出了"建筑·交通一体化"的综合设计策略。     

Design chart for the modified hyperbolic method

The modified hyperbolic method is used in practice to predict the ultimate primary consolidation settlement of compressible ground. This paper presents a new relationship between the average degree of consolidation for combined vertical and horizontal consolidation U_vh and the non-dimensional vertical time factor T_v, with a new parameter, ν_hv, introduced. ν_hv is defined as the ratio of the time factor in the horizontal direction to that in the vertical direction. This relationship is then adopted to calculate the slope of the linear segment of the theoretical hyperbolic plot (T_v/U_vh vs T_v), λ, which is a key factor in the modified hyperbolic observational method presented by Tan (1995). A design chart for λ as a function of ν_hv is proposed. Using this design chart, the determination for λ can be simplified from a procedure involving three parameters to only one, ν_hv. A new procedure for the use of the modified hyperbolic method is proposed. The new procedure is verified using a well-documented case history.     

让建筑回归社会——荷兰女建筑师玛丽丝·罗默尔作品及访谈

玛丽丝·罗默尔是当代荷兰知名女建筑师,其设计作品与理念有着鲜明的特色,善于从社会、环境出发探讨建筑之于城市的意义。同时她将女性建筑师的细腻敏锐以及富有艺术气质的特点注入作品之中。本文通过对玛丽丝·罗默尔的访谈及其代表作品和设计理念的简介诠释,并引发对荷兰建筑师群体特征的评价。     

工字截面50 t吊梁的设计

吊梁是大型设备吊装的专用吊具,吊索与水平面的夹角越小,吊索受力越大,对吊梁的轴向压力也就越大。吊装水平长度大的构件时,为使构件的轴向压力不致过大,同时吊索不占用较大的空间高度,吊索与水平面的夹角应在60°～75°。吊梁结构形式有多种,采用常见的H型钢制造,并依据《钢结构设计规范》（GB50017—2003）推导出工字截面尺寸直接算法,初选截面,然后进行结构强度、刚度和结构稳定性验算,确保吊梁的安全使用。     

山体滑坡成因及治理

文章通过对铜陵市人民医院西侧山体滑坡的成因分析,提出遵循确保安全、施工可行、经济合理、主动防护的设计原则,采取支挡、锚固、排水等综合治理措施,解决了山体滑坡的险情。