桥梁美学设计及其进展

阐述在桥梁设计中进行美学考虑的必要性和重要性,指出现代桥梁设计应把强化桥梁技术品质与体现桥梁美学价值相统一,同时还要与其周围的环境相协调融合。介绍桥梁美学理论及美学设计的实现,结合生态审美的理念分析展望了桥梁美学设计的未来发展趋势。     

大块金属玻璃的热稳定性

通过差动热分析（ＤＳＣ）试验测定了Ｚｒ－１０６合金的玻璃转变温度Ｔｇ和初始晶化温度Ｔｘ,利用Ｘ射线和透射电子显微镜（ＴＥＭ）对该合金在Ｔｇ－Ｔｘ温度区间经不同温度和不同时间热处理后试样的显微结构进行了分析,并在Ｔｇ－Ｔｘ温度区间对该合金进行热锻变形,结果表明,该合金的Ｔｇ－Ｔｘ分别为３２５℃和４７０℃,在低于晶化温度Ｔｘ以下热处理几科下不发生晶化,其厚度方向的变形量可达２００％,由此得出Ｚｒ－１０     

一种基于SEA方法的舰艇防空作战电子对抗作战效能评估模型研究

文章运用SEA方法对舰载电子对抗作战构建了一个效能评估模型,并对评估参数提供了量化分析工具。利用实例计算对评估参数进行了分析,对电子对抗作战提出了参考意见。     

基于变权重的多因子来袭导弹威胁评估

为了能有效地对复杂战场态势进行估计,确定导弹阵地面临的威胁等级,文章提出了变权重的多因子来袭导弹威胁评估。能很好地反映战场的真实情况,为决策者提供有效快速的防护决策依据。通过仿真实例验证了该算法的有效性。     

预制沉箱表面缺陷的成因分析及其改善对策

沉箱预制是重力式码头的主要分项工程,其预制质量直接影响码头的整体质量。结合汕头港广澳一期工程沉箱重力式码头的施工监理实践,分析大型沉箱预制表观质量缺陷常出现的位置;实际使用的材料、施工环境、人员操作等因素对表观质量缺陷成因的影响;并介绍采取的对策和取得的效果。     

Numerical solutions for a two-dimensional airfoil undergoing unsteady motion

Continuous vorticity panels are used to model general unsteady inviscid, incompressible, and two-dimensional flows. The geometry of the airfoil is approximated by series of short straight segments having endpoints that lie on the actual surface. A piecewise linear, continuous distribution of vorticity over the airfoil surface is used to generate disturbance flow. The no-penetration condition is imposed at the midpoint of each segment and at discrete times. The wake is simulated by a system of point vortices, which move at local fluid velocity. At each time step, a new wake panel with uniform vorticity distribution is attached to the trailing edge, and the condition of constant circulation around the airfoil and wake is imposed. A new expression for Kutta condition is developed to study (i) the effect of thickness on the lift build-up of an impulsively started airfoil, (ii) the effects of reduced frequency and heave amplitude on the thrust production of flapping airfoils, and (iii) the vortex-airfoil interaction. This work presents some hydrodynamic results for tidalstream turbine.     

Time-fuel synthetic optimal control of ship-borne special crane based on predictive average dynamic

Ship-bome special crane, a multi-joints and foldaway one, is important to study the most effective energy-saving ( i. e. synthetic time-fuel optimal) operation control mode. In this paper, by introducing weighted parameters, a time-fuel synthetic optimal criterion is obtained, and configuration of the optimal controller is verified. Furthermore, a predictive average dynamic method is put forward, and applied to treat nonlinearity and coupling of the crane. Finally, an optimal controller with feedback is designed. The validity of this approach is verified by simulation results.     

基于路堤设计荷载的软基固结度分析及应用

在已有软土地基固结度计算理论的基础上,对某高速公路软土地基试验段监测资料进行分析,提出了基于路堤设计荷载下的软土地基固结度计算方法,工程实例表明理论计算与实测结果符合程度较好,为路堤超载设计、卸载时机的计算确定提供了依据。     

Fluctuation velocity correlation closure model for dense gas-particle turbulent flow

Turbulence model of kg-εg-kp-εp-kpg-θ is proposed.In the model,the two-phase velocity correlation turbulent kinetic energy k pg is modeled by transport equation.To close this turbulence model,algebraic expressions of two-phase Reynolds stresses and two-phase velocity correlation variable are established by considering both gas-particle interaction and anisotropy.This turbulence model is used to simulate dense gas-particle flow in a riser and in a downer.The predicted results show the core-annulus flow structure observed in the riser and the skin effect of particle concentration in the downer.The present model gives simulation results in much better agreement with the experimental results than those obtained by kg-εg-kp-εp-θmodel which is simply closed using a semi-empirical dimensional analysis.     

姜黄素对沙土鼠脑缺血再灌注后海马CAl区及CA3区Bcl-2、Bax表达的影响及意义

目的探讨姜黄素对沙土鼠脑缺血再灌注后凋亡相关基因Bcl-2、Bax在海马CA1区、CA3区表达的影响及意义。方法制作沙土鼠双侧颈总动脉阻断缺血再灌注损伤模型。随机分为假手术组（SH）．脑缺血再灌注组（IR）、姜黄素组（CU）、对照组（SC），每组据再灌注时间点不同又分为1、3、5、7d4个亚组，每组6只动物。在预定时间点行开阔法行为学检查，TUNEL法检测海马CA1区、CA3区细胞凋亡，免疫组织化学染色测定Bcl-2、Bax蛋白在海马CA1区、CA3区的表达变化。结果姜黄素可显著减少沙土鼠探索活动及海马CA1、CA3区凋亡锥体细胞数量（与IR组相比，P〈0．01），诱导Bcl-2蛋白及抑制Bax蛋白表达（与IR组相比，P〈0．01）。结论姜黄素有脑保护作用，调控凋亡相关基因Bcl-2、Bax蛋白的表达可能是其作用机制之一。