Experimental Investigation on Buckling Behaviors of Irregularly Shaped Aluminum Alloy Structural Components Under Axial Compression Load

The experimental and numerical investigations on buckling behaviors of aluminum alloy components with different irregularly shaped sections were carried out. The buckling load carrying capacity obtained through experiments, numerical simulations, and equations described in the design code were compared. Results obtained through experiments and numerical simulations in good agreement, which shows the validation of the numerical model. And the validated FEM model will be used for parametric analysis of buckling behavior of irregularly shaped aluminum alloy structural component. Equations in the design code do not include effects of the buckling type and need to be improved further.     

Wind Power Utilization Efficiency on Roof of Rectangular Buildings

Installing small wind turbines on the roof of buildings is a new way of wind power utilization in recently years. Based on the annual mean wind speed, the efficiency of wind power utilization on roofs of buildings was studied and the evaluation indexes for the utilization efficiency were proposed. With the help of CFD numerical analysis, the analysis on wind power utilization efficiency on flat roofs of rectangular buildings was carried out. The performance indexes of reference points under different windward angles were investigated. The best position and arrangement of wind turbines on the roof were also discussed. Furthermore, the utilization efficiency of four roofs with different shapes were analyzed and compared with that of flat roof.     

Effect of surface defects on anodic oxidation coating of7075 aluminum alloy

The interface interaction between geogrid and soil is one of the key issues on geosynthetic reinforced soil structures. Comparative analysis of properties of geogrid clay interface under the different normal stresses and water contents of clay were conducted by medium sized pullout tests. The results show that ultimate pullout force of geogrid, interfacial cohesion and frictional coefficient are significantly affected by water content of clay. Ultimate pullout force of geogrid tends to be remarkably different when subjecting to different normal stresses at a lower water content. And frictional coefficient of interface decreases with the increase of water content, and interfacial cohesion has a tendency to increase followed by decrease with the increase of water content. Moreover, aforementioned three parameters can keep constant when water content is close to value at plasticity limit. The curves of load and displacement possess three stages: linear increase, non linear increase and ultimate pullout. As water content increases, the interval nonlinear changing stage is not conspicuous. Furthermore, it is found that geogrid strains in transversal ribs tend to increase but to reduce in longitudinal ribs when last level load is kept for given hours and then followed by unloading pullout force.     

Flow Stress Behavior of 3104 Aluminum Alloy

According to different deformation conditions required in working process for manufacturing of 3104 aluminum alloy, the authors design the simulation experiments of hot rolling process at different deformation temperature and strain rates, analyze the relationships of deformation resistance, flow stress and strain rate, deformation temperature when alloy deformation. Based on experimental data analysis, it was concluded that the dominant factors affecting flow stress were the strain rate and deformation temperature, and the two parameters were also important for deforming process control.     

Review on the Research of High-strength Wrought Magnesium Alloy ZK60

ZK60 magnesium alloy is one of high-strength wrought magnesium alloys. Owing to its high strength and low density, it has nearly the highest strength to density ratio among existing materials. Because its strength approximates to high-strength aluminum alloy 7075, it has promising application future. The history of magnesium alloy ZK60 and researches on its microstructure, mechanical properties, surface treatment, and the effects of alloy elements and microelements are reviewed . Further more, the authors put forward methods to improve its microstructure and mechanical properties and prospected the development future of this alloy in the aspects of surface treatment and application.     

Numerical Simulation of Eelastoplastic Multi-scales Model for Casting Magnesium Alloy

To realize the transforms of stress and strain and obtain the multi-scale constitutive equation across micro/meso/macro scales.strain-stress curves for magnesium alloy(AM60) and magnesium matrix are carried out with the machine MTS.By means of mixture law,mechanical property of particle is obtained.Based on the character of magnesium alloy structure,the finite element model of unit-cell included complex micro-structures is carried out.Via finite element numerical simulation of magnesium alloy unit-cell,the methodology overcome the limitation of present analytical method.Finally the multi-scale constitutive equation has been used for the analysis of the tensile stress vs. strain curve for magnesium alloy.Results show satisfactory agreement between the stress vs strain curve by the present methodology and the experimental data for AM60.     

Advance in Spray Forming Technology and Its Prospect

Spray Forming technology gets involved with new materials preparation techniques in multiple domains such as powder metallurgy, fluent metal atomization, rapid cooling and non-equilibrium solidification. High performance alloy and metal matrix composite with high density, low oxygen content and microstructure featuring rapid solidification can be fabricated by spray forming. Spray forming, which is of short process flow, low cost, high deposition efficiency, flexible manufacture system, becomes a kind of near shape forming and rapid solidification technology with great prospect. Therefore the developing process history of spray forming technology is introduced and the current research and development status of spray forming technology in the fields of aluminum alloy, steel material, magnesium alloy, copper alloy and high temperature alloy and metal matrix composite is described. Multi-layer spray forming and in-situ reaction atomization spray forming are also discussed. In addition, evaluation and prospect for the technology are presented.     

深部大跨度切眼顶板分区控制技术

针对深部大跨度切眼顶板自稳能力差、变形剧烈、支护困难等问题,以赵固二矿1105大采高工作面切眼支护为工程背景,综合现场调研、理论分析、顶板探测等方法,分析了深部大跨度切眼冒顶机理和不同顶板的控制关键,提出了以接长锚杆支护为主导的顶板分区控制技术,阐明了不同顶板分区的控制原理。据此,对赵固二矿1105切眼二次成巷进行了支护设计,并进行了顶板下沉量和顶板失稳垮落规律监测,结果表明：接长锚杆与中部层位顶板共同形成的“锚固体岩梁”呈现出较好的稳定性,各层位顶板均得到了有效控制,保证了切眼顶板安全与正常服务。     

Thermal Inertia of Extensive Green Roof

Thermal performance of the green roof is an important basis for energy-efficient design and evaluation. However, the current studies on the thermal performance of the green roof seldom involve thermal inertia of the green roof. Based on a long-term experiment of an extensive green roof in natural ventilation state and a five-month ongoing measured data in summer, thermal inertia of the extensive green roof was studied by statistical analysis method. The results show that thermal decay to outdoor climate effect through green roof was increased by more than 100% and delay time of thermal response to outdoor climate on internal surface of the green roof was reduced in comparison with that of the bare roof.     

Evaluation of Ecological Effect of Roof Greening

To evaluate ecological effect of roof greening, AHP and Delphi Technique were adopted to collect qualitative data of roof greening, RS and GIS to collect quantitative data. These techniques greatly promote the rate and precision of data collection and processing, and lay a foundation for quantitative analysis of roof greening analysis. Moreover, weights of all indexes were specified. Exponential weighting statistical evaluation was applied for quantification of single index. On this basis, the collected data were standardized and their role and interaction were analyzed by using multivariate method, integrated and evaluated. Evaluation objects of roof greening ecological effect were appraised comprehensively through qualitative analysis (dominant) and quantitative analysis (secondary).     

52份豌豆种质萌发期耐铝毒性的综合评价与筛选

随着土壤酸化的日益加重,铝毒成为影响作物种子萌发质量以及产量的重要胁迫因子之一。本研究采用单项耐铝毒系数(AC值)、综合耐铝毒系数(CAC值)、平均隶属函数值(ASF值)、耐性综合评价值(A值)等指标及相关分析、主成分分析、聚类分析和逐步回归分析等方法,综合评价豌豆种质萌发期铝毒耐性,建立综合筛选评价体系,并筛选萌发期耐铝毒豌豆种质。利用筛选出的适宜浓度40 mg L–1Al3+处理52份豌豆品种(系)种子,结果显示,萌发期8个相关性状在处理组及对照组品种间均存在显著差异,遗传多样性指数分别介于1.43～2.03和1.51～2.06之间。基于AC值聚类分析, 52份豌豆种质可被分为3个耐性级别,其中,第I级含2份,为耐铝毒品种(系);第II级含19份,为敏感品种(系);第III级含31份,为铝毒极敏感性品种(系)。利用豌豆种子发芽率、发芽势、发芽指数、芽长、根长、芽干重、根干重7项指标,结合最优回归方程可初步鉴定豌豆萌发期耐铝毒特性。通过综合评价和聚类分析,筛选出萌发期铝毒耐性极强的种质C175和C145,可作为豌豆铝毒耐性育种和耐性机制研究的重要资源。     

Heat Transfer Simulation and Experiment of Highly Efficient Regenerator

On the base of regenerator configuration character, the heat transfer mathematics models are set up. The relevant relations of regenerator medium, exchange time, temperature efficiency and thermal efficiency are analyzed by numerical simulation. The results are anastomotic by numerical simulation and by experiments after exchanging 7 - 10 s. And it indicts reliability by simulation. The authors study effects of exhaust gas temperature and air preheat temperature influenced by regenerator medium, exchange time etc. , by numerical simulation and experiment. On the case, the suitable exchange time of corundum globule is about 60s, the suitabe exchange time of high aluminum and clay ceramic ball is 20 -30 s. Temperature efficiency is up more than 80%, thermal efficiency is up more than 70%.     

Indoor Thermal Environment for Green Roof

Roof planting is widely recognized as a ecological thermal insulation for roof. A lightweight green roof in climatic conditions of shanghai was investigated as a case study by applying PMV index to calculate thermal comfort compared with that with traditional roof in air conditioning. It is found that the PMV value of green roof is 0.2 lower than that of traditional roof, while the fluctuating range of green roof was only 1/4 of that of traditional roof. And the equivalent thermal insulating roof of green roof was obtained by computing. Furthermore, it is shown that green roof has lower interior surface temperature than equivalent insulating roof in the condition of higher indoor temperature.     

Structural Design on Guangzhou Gymnasium Roof

In this paper the monolithic structural design and joint design of Guangzhou Gymnasium steel roof are introduced. The calculation analyses, including static analysis, dynamic analysis and buckling analysis are introduced as well.     

铝胁迫条件下小麦根系特异表达基因的研究

利用尼龙膜点阵杂交技术,由耐铝胁迫小麦品系OK91G106根系构建的cDNA差减杂交文库中,鉴定出29个铝胁迫特异诱导基因,包括20个已知生物学功能的基因和9个功能未知基因。这20个已知功能基因归属于植物体内细胞信号转导、活性氧清除、维持膜结构稳定、苹果酸分泌和细胞保护等等类别。表明在铝胁迫下,植株体内在短时间内发生了感受铝胁迫逆境信号并进行了信号转导,调控了植株对铝胁迫逆境响应的复杂分子生物学过程。Northern印迹对5个铝诱导基因转录本的检测结果与尼龙膜点阵技术获得的结果相一致。本研究鉴定出的铝诱导基因中含有1个苹果酸转运蛋白基因,表明苹果酸分泌量的增加可能是供试小麦响应和抵御铝胁迫逆境的重要机制之一。     

The Building and Roof Garden

The roof garden has great functioning of smoothing the shortage of land resource in the city and making use of the land resource diversity and efficiently. It is an efficient and reasonable way to exploit the open space the roof of the building. From the classic roof garden of the world, we can find out that roof garden has close relationship with the building. Roof garden is different with other kind landscape in the city, it needed cooperation of landscape architect and architect from at the stages of design, construction, upholding and management. We should attach importance to roof garden in the construction of building.     

Dynamic Heat Transfer Analysis of a Water Storage Roof

On the basis of analyzing the complicate heat and humid exchange between the outdoor air and the water layer of the roof,the authors obtained a heat transfer model and it's transmit matrix. The temperature and heat flux responses of the internal roof surface is greatly lowered than that of non-water layer roof. It can be concluded that the maintenance of a water layer on the roof is a good way to resist the fluctuation of outdoor temperature and significantly reduce the cooling load of a building.     

Research on Assembly Construction, Positioning Control and its Detecting Technology for Retractable Roof Structure of Glass Skylight in Guiyang Southwest International Trade City

The retractable roof structures are developing technology for commercial buildings. The charecteristics of retractable roof structure of glass skylight, which is defferent with other retractable roof structure were introduced through an actual project in     

屋顶绿化的简史、现状与发展对策

屋顶绿化、屋顶花园虽然发展较早,但人们对它的要求日益迫切,通过对全国一些地方特别是 湖南长沙市的屋顶绿化和屋顶花园建植过程进行研究后发现,各项相关的科研、政策、法律法规发展 相对较慢,从而引发了诸多矛盾和不良后果,在调查研究的基础上,通过科学分析得出,为了使屋顶 绿化和屋顶花园健康持续地发展,从而充分发挥其应有的生态、环境、社会效益,应采取以下几个策 略:(1)加大施工队伍的设计、施工等技术培训,(2)加大政府监管,(3)加大政策和法律指导,(4)加强科 学实验。     

彩钢板屋顶高大平房仓仓顶喷涂反射隔热涂料的应用效果

分析了彩钢板屋顶高大平房仓喷涂太阳热反射隔热涂料对仓顶温度、仓温、粮温的影响,为彩钢板屋顶高大平房仓控温储粮寻找一种有效方法。试验结果表明,喷涂太阳热反射隔热涂料对控制彩钢板屋顶高大平房仓仓温效果明显,同时可以达到延缓仓顶彩钢板老化、改善仓内工作环境和节能减排的目的。