Abstract:为研究HPFL(High-performance ferrocement laminate)加固RC梁的极限荷载与温度变化之间的关系,对4根三面U形加固(在梁的受拉面和侧面进行加固)RC梁通过自行研制的高温试验炉在常温(20℃),400℃,600℃和800℃温度条件下分别进行恒温加载试验,研究了使用这种技术加固的RC梁的极限荷载与温度之间的关系,并比较了它们的挠度和破坏形式.通过与常温下的对比梁相比,HPFL加固的RC梁的极限荷载随着温度的增加而减小,加固梁破坏时的挠度随着温度增加而增大,且推导出了HPFL加固RC梁的极限荷载与温度之间的关系.

Abstract:An experimental study was conducted on the flexural behavior of reinfoced concrete beam strengthened by Polyvinyl Alcohol-Engineered Cementitious Composite(PVA-ECC) mortar subjected to one-off load and secondary load.Based on the comparison of the test results of six beams reinforced by PVA-ECC steel mesh and one general beams,the effect of tension reinforcement ratio on the flexural strength and deflections capacity was studied.Beams were reinforced with U-shape,and crack distribution,load-max deflection,s...

Abstract:On the basis of a brief review of aluminum alloy bridges decks,the concept model of aluminum alloy bridge deck was obtained with the topologic optimization technology of ANSYS.Considering the strength and the stiffness required and the extrusion production capacity of the aluminum alloy decks,two kinds of aluminum alloy decks were designed and the detailed sizes of the two kinds of aluminum alloy decks were optimized.The results have shown that the stiffness of aluminum alloy decks obtained with the topolog...

Abstract:By using wave function expansion method,the dynamic response analysis of a deep buried cylindrical composite-lining cavity in an elastic space subjected to incident plane SH waves was studied.By compiling programs with the obtained series solution and mathematical application software MathCAD,the main factors affecting the dynamic stress concentration of the surrounding rock and composite-lining structure,such as the frequency of incident waves,the ratio of the size of composite-lining structure and the ela...

Abstract:To minimize thorax-abdomen injuries in side impact and to make sure that HIC meet C-NCAP requirements,an optimization design of head-thorax airbag was conducted by using the validated FE models,the stepwise regression surrogate model and successive optimization method.An L-shape head-thorax airbag model was established and installed on a validated vehicle FE model.The response process of the airbag in side impact was simulated in combination with driver model.The airbag design parameters were analyzed and o...

Abstract:The structural design and optimization method of the octagonal beam with step by step energy absorbing characteristics were introduced.The finite element model of the beam was developed and validated through sled test.Uniform design method was used to set the scheme of the impact simulation of the beams with different thickness.The crashworthiness regression formulations were defined on the basis of the simulation results,and regression analyses were conducted.The Genetic Algorithm(GA) was used in the multi...

Abstract:The grinding temperature and the grinding force were measured by using the thermocouple technique and 3-axis piezoelectric dynamometer in the grinding process of GCr15 harden steel.The residual austenite content,the subgrain size of the martensite and the micro-strain in the grinding surface were analyzed on the basis of X-ray diffraction(XRD) examinations of the microstructure.The contact stress and the plastic strain of the grinding surface were simulated by using the finite element method(FEM).The effect...

Abstract:Considering the limitations when the handling stability research methods of cars are applied to tractor trailer,a new research method and an improved measure for handling the stability of tractor-semitrailer were proposed.A system dynamic model of tractor-semitrailer including saddle damping parameter was established,and computer simulation was done under 'S' lane-change working conditions.The relative change response characteristics of the tractor's motion parameters,such as the rolling angle and lateral a...

Abstract:Four polishing tools with different shapes were designed for the magneto-rheological finishing test of K9 flat glass by using a 3-axis CNC milling machine with developed magneto-rheological fluid.The influence of the shape of polishing tools on the surface roughness was investigated in terms of magnetic intensity,working gap and the rotational speed of magnetic pole.Polishing results have shown that flat polishing tool with crossed grooves is the most effective.Under similar conditions,the flat polishing to...

Abstract:针对在实际的多属性语言群决策问题中属性之间往往具有相互关联作用这一问题,提出了一种考虑属性关联的TOPSIS语言群决策方法.该方法中决策者给出对方案的语言评价信息,并采用二元语义概念对语言评价信息进行处理.在传统理想点法的基础上引入λ模糊测度的概念,根据属性间的关联作用确定每个方案属性的权重并得到加权决策矩阵.然后计算每个方案与正、负理想点间在n维二元语义空间内的二元语义欧氏距离并得到相对贴近度,确定最优方案.该方法有效地避免了决策过程中语言评价信息的扭曲和损失,并能够考虑属性间的关联作用对于属性权重的影响,使得决策结果更加合理可信.通过一个实例验证了方法的有效性和实用性.

Abstract:Al-20Si/SiCp composite was fabricated by spray deposition.The thermal fatigue behavior of Al-20Si/SiCp composite was investigated in the water-quench method.Optical microscopy(OM) and scanning electron microscopy(SEM) were used to examine the damage mechanisms of thermal fatigue.Almost all the primary fatigue cracks at an elevated temperature initiated at V-notch.After several thermal cycles,the speed rate of crack propagation decreased with the relative density of composite increase.Because-Al matrix could...

Abstract:Zn0.9Ni0.1O nanorods were fabricated by sol-gel method.The XRD results showed that there was not any pure nickel or nickel-oxide in the samples,and the majority of Ni atoms was incorporated at Zn substitutional sites.The calcined temperature was the key factor of the formation of nanorods indicated by SEM images.The sample turned to the punctate grains from pillars with the tempareture raised.The measurement of magnetism was carried out by a vibrating samples magnetometer(VSM),and it was found that the samp...

Abstract:2-取代苯胺与巴豆醛反应合成了5种8-取代喹哪啶.讨论了反应因素对反应的影响,得到了较好的结果.8-取代喹哪啶的结构经1HNMR和MS分析确证,并用单晶X-射线衍射测定了化合物Ⅰa和Ⅰb的晶体结构.化合物Ⅰa晶体属正交晶系,空间群为Pca21,晶胞参数为:a=1.279 61(9)nm,b=0.506 60(4)nm,c=1.311 81(9)nm,Z=4,V=0.850 38(11)nm3,Dc=1.387 g/cm3,F(000)=368,R1=0.028 8,wR2=0.073 1,S=1.01;化合物Ⅰb晶体属单斜晶系,空间群为P21/c晶胞参数为:a=0.504 40(17)nm,b=1.346 7(4)nm,c=1.339 1(4)nm,β=97.678(4)°;Z=4,V=0.901 4(5)nm3,Dc=1.636 g/cm3,F(000)=440,R1=0.071 1,wR2=0.195 1,S=1.09.选择合适溶剂和添加剂,反应收率较文献值有较大提高.

Abstract:采用5%Pd/C作为转移氢催化剂,4-异丙基环己烯酮为氢给予剂,工业双戊烯为氢接受剂和溶剂进行反应,合成了对异丙基苯酚.考察了催化剂用量、反应时间和反应温度对反应的影响,确定了合成对异丙基苯酚的最佳反应条件:原料与5%Pd/C的配比为10∶0.7(质量比)、反应时间为30 min,在174℃回流温度下,对异丙基苯酚的产率可达87%.对催化剂的重复使用次数进行了考察,使用5次后催化剂活性是原来的89.7%.

Abstract:A yttrium layer was electrodeposited on the surface of PAN-based carbon fibers in yttrium nitrate ethanol solution,and the corresponding morphology of the yttrium layer was investigated through scan electron microscopy.The loading mass of the yttrium on the surface of PAN-based carbon fibers was controlled by the charge during the electrochemical deposition.The effect of yttrium on catalytic graphitization of PAN-based carbon fibers was investigated by X-ray diffraction(XRD).The mean crystallite size(Lc) an...

Abstract:The physiological and ecological effects on Vetiveria zizanioides(V.zizanioides)grown in hydroponic culture under the stresses at different concentration of Cadmium(Cd)were studied.The experiment results showed that Cd mainly cumulated in the root.The highest Bioconentration factor(BF) was 34%.of Cd with a positive correlation with Cd cumulation in the root(r=0.987 4),while the concentration had a negative correlation with a tolerance index of the root(r=-0.943 6).The root activity and nitrate reductase(NR)...

Abstract:Power quality transients can cause heavy loss to sensitive loads.By adopting multi-resolution analysis idea of wavelet transform,fractal theory was used to classify and analyze the power quality transients from the point of view of graphic pattern recognition.The simple box dimension was used for primary analysis,the waveform was segmented according to the distribution of the box,and the key segmentations containing transients were abstracted for further analysis through fractal and wavelet transform.The re...

Abstract:A set of unstructured data analysis and retrieval system designs were proposed.Distributed technology in the windows platform was used to establish a set of task-distribution servers for the central task of computing the terminal processing unit,with feedback sand fault-tolerant mechanisms for the distributed data retrieval system.Based on the given system model and the idea of design,the modular design of the various functional components was done and the failure of each module was tested.The results have ...

Abstract:A study of the portfolio selection using CVaR strategy with data uncertainty was conducted.Ways to formulate and solve robust portfolio selection problems based on recent progress in robust optimization were proposed.By using statistic theory and time series techniques,we constructed an ellipsoidal uncertainty set which contained the most possible realizations of uncertain parameters.Then the original problem was converted to a deterministic problem which could obtain a solution good for the most possible r...