Lattice structure on some fuzzy algebraic systems

In this paper, we study the lattice structure of some fuzzy algebraic systems such as (G-)fuzzy groups, some fuzzy ordered algebras and fuzzy hyperstructures. We prove that under suitable conditions, these structures form a distributive or modular lattice. This research partially is supported by the “ Fuzzy Systems and its Applications Center of Excelence, Shahid Bahonar University of Kerman, Iran”.     

Fatigue Behavior and Retrofit Investigation of Distortion-Induced Web Gap Cracking

This paper studies a Kansas Department of Transportation welded plate girder bridge that developed fatigue cracks at small web gaps close to the girder top flange. Repair had been previously performed by softening the connection plate end with a slot retrofit, but cracks were recently found to have reinitiated at some of the repaired details and are again propagating. A comprehensive finite-element method study was performed to investigate the cracking behavior observed in the bridge and to recommend appropriate measures for future bridge retrofit. The analytical results show that stresses developed at the top flange web gaps could exceed yielding under the loading of an HS15 fatigue truck. The current slot repair used in the bridge was found to have introduced higher magnitude fatigue stresses in the web gap. To achieve a permanent repair of the bridge, it is recommended that a welded connection plate to flange attachment be used during future bridge retrofit. The web gap details should be able to withstand unlimited number of load cycles once this additional repair is performed.     

An analysis of the electrical conductivity in BaSO4-added Ag2SO4 solid electrolyte system

The compositions (1 −x)Ag₂SO₄−(x)BaSO₄, wherex=0·01 to 0·6, were prepared by slow cooling of the melt. The extent of the solid solubility of Ba²⁺ in Ag₂SO₄ was determined by X-ray powder diffraction and scanning electron microscopy. The bulk conductivity of each sample was obtained using a detailed impedance analysis. The partial substitution of Ba²⁺ results in the enhancement of conductivity in compliance with the classical aliovalent doping theory. A simplistic model based on lattice distortion (expansion) due to partial substitution of Ag⁺ by the bigger Ba²⁺ has been considered to explain enhanced conductivity. Beyond solid-solubility limit (5·27 mole%) the BaSO₄-dispersed Ag₂SO₄ conductivity follows the usual trend seen in binary systems. An increase in conductivity in this case is discussed in the light of interfacial reactions and surface defect chemistry. The maximum conductivity in 20 mole% BaSO₄ dispersed Ag₂SO₄ is due to percolation threshold.     

几何造型的自由畸变方法

几何造型是计算机图形学的重要研究内容，ＣＡＤ／ＣＡＭ的核心技术，现行的许多造型系统仅限于造型二次曲面及旋转曲面，没有自由曲面造型能力，本文研究的自由畸变为法，很容易扩展这些系统的自由曲面造型功能，该方法已成功地用于扩展ＭＯＶＩＥ．ＢＹＵ系统的自由曲面造型功能。     

预应力混凝土箱梁主要裂缝成因和防治措施的探讨

预应力混凝土连续箱梁的裂缝问题一直以来倍受桥梁界专家及技术人员的关注。本文通过对预应力混凝土连续箱梁主要裂缝产生的原因进行了浅析，并提出了相应的防治的措施。     

Studies on nucleation kinetics of InxGa1−xN/GaN heterostructures

Nucleation kinetics during the growth of In_xGa_1−xN on a GaN substrate have been studied. The behavior of nonequilibrium between the In_xGa_1−xN and the GaN substrate has been analyzed, and hence, the expression derived for the stress-induced supercooling/superheating has been numerically evaluated. The maximum amount of stress-induced supercooling is found to be 1.017 K at x=0.12. These values are incorporated in the classical heterogeneous nucleation theory. Using the regular solution model, the interfacial tension between the nucleus and substrate and, hence, the interfacial tension between nucleus and mother phase and thermodynamical potential of the compounds have been calculated. The amount of driving force available for the nucleation has been determined for different compositions and degrees of supercooling. It has been shown that the value of the interaction parameter of InN-GaN plays a dominant role in nucleation and growth kinetics of In_xGa_1−xN on a GaN substrate. These values have been used to evaluate the nucleation parameters. It is shown that the nucleation barrier for the formation of a In_xGa_1−xN nucleus on a GaN substrate is minimum in the range of x=0.12 to x=0.17, and it has been qualitatively proved that good quality In_xGa_1−xN on GaN can be grown only in the range 0<x≤0.2.     

钢筋混凝土连续曲线箱梁设计探索

以上海市沪闵路高架道路二期工程SW匝道曲线箱梁设计为例 ,对曲线梁的内力特点及调整方法作了初步探索。     

三峡水利枢纽右岸三期工程预应力门机大梁施工工艺

三峡水利枢纽右岸三期工程坝顶预应力门机大梁高度大、跨度长、钢筋密集、结构体型复杂、张拉吨位大、张拉要求高。针对门机大梁以上特点,对梁体模板设计、混凝土浇筑振捣、梁体张拉施工技术难点进行了深入研究。     

非标压力机箱形主梁全约束优化设计

根据非标设备结构优化问题的特点,给出满足《钢结构设计规范》(GBJ17 88)规定的箱形主梁全约束优化设计方 法。将编制的内罚函数法优化程序应用于主梁的设计,计算结果表明,该优化方法可应用于实际设计。