冷轧薄宽带钢局部型中浪瓢曲变形行为研究

针对薄宽带钢冷轧过程中易发多发的局部型中浪瓢曲缺陷,引入非均匀载荷宽度、弹性约束系数及平均张应力建立了屈曲变形的解析计算模型。应用能量最低原理对屈曲变形区域进行搜索求解,得到了局部型中浪屈曲临界条件(包括临界应力、屈曲波长和屈曲波宽),获得了其与非均匀载荷宽度、弹性约束系数、平均张应力的关系,并发现平均张应力是产生局部型中浪的重要影响因素。应用样条有限元方法对局部型中浪进行数值仿真分析,验证了屈曲解析计算方法的正确性。在实验轧机上进行了轧制研究,通过轧制获得了局部型中浪屈曲模态,对实验结果分析得到了相对应的屈曲临界条件,与解析法和样条有限元法结果基本吻合,证明了样条有限元计算方法与解析计算方法的正确性及其工程应用价值。     

INFLUENCE OF DAMPING MODELS ON DYNAMIC ANALYSES OF A BASE-ISOLATED COMPOSITE STRUCTURE UNDER EARTHQUAKES AND ENVIRONMENTAL VIBRATIONS

Structural design simultaneously governed by earthquakes and environmental vibrations has received a lot of attention in recent years.Base-isolated composite structures are typically used in the above-mentioned structural design.The corresponding analysis involves validating structural safety under earthquakes and human comfort under environmental vibrations through a time-history analysis.Thus,a reasonable damping model is essential.In this work,the representatives of viscous damping model and rate-independent damping model,namely the Rayleigh damping model and uniform damping model,were adopted to investigate the influence of damping models on the time-history analysis of such structural designs.The energy dissipation characteristics of the above-mentioned damping models were illustrated via a dynamic test of recycled aggregate concrete specimens.A case study was performed on a base-isolated steelconcrete composite structure.The dynamic responses under the excitation of earthquakes and environmental vibrations were compared using different damping models.The uniform damping model was found to be more flexible than the Rayleigh damping model in dealing with excitations with different frequency components.The uniform damping model is both theoretically advantageous and easy to use,demonstrating its potential in dynamic analysis of structures designed simultaneously governed by earthquakes and environmental vibrations.     

A VIBRATION RECOGNITION METHOD BASED ON DEEP LEARNING AND SIGNAL PROCESSING

Effective vibration recognition can improve the performance of vibration control and structural damage detection and is in high demand for signal processing and advanced classification.Signal-processing methods can extract the potent time-frequency-domain characteristics of signals;however,the performance of conventional characteristics-based classification needs to be improved.Widely used deep learning algorithms(e.g.,convolutional neural networks(CNNs))can conduct classification by extracting high-dimensional data features,with outstanding performance.Hence,combining the advantages of signal processing and deep-learning algorithms can significantly enhance vibration recognition performance.A novel vibration recognition method based on signal processing and deep neural networks is proposed herein.First,environmental vibration signals are collected;then,signal processing is conducted to obtain the coefficient matrices of the time-frequency-domain characteristics using three typical algorithms:the wavelet transform,Hilbert-Huang transform,and Mel frequency cepstral coefficient extraction method.Subsequently,CNNs,long short-term memory(LSTM)networks,and combined deep CNN-LSTM networks are trained for vibration recognition,according to the time-frequencydomain characteristics.Finally,the performance of the trained deep neural networks is evaluated and validated.The results confirm the effectiveness of the proposed vibration recognition method combining signal preprocessing and deep learning.     

有限宽度和椭圆孔形状对缺口层合板强度预测的影响

本文采用有限元方法对正交各向异性材料含有不同椭圆孔形状的有限宽度板作了分析,给出了有限宽度和椭圆孔形状对应力集中因子K₁和孔边应力分布σ_y(x,0)的影响公式。数值结果表明:正交各向异性板的有限宽度和椭圆孔形状对K_r和σ_y(x,0)的影响均与各向同性材料不同,所以有限宽度和椭圆孔形状将对缺口层合板强度的预测产生影响。      

复合材料加筋板的动力分析

本文构造了九自由度三角形拟协调罚函数复合材料板单元与六自由度复合材料梁单元,考虑了剪切变形与转动惯量的影响。用这两种单元对复合材料加筋板的自由振动、阻尼特性和瞬态响应问题进行了研究,给出一些有益结果。      

数字3D电影最新动向

全球数字3D电影领域的领头羊Real D公司于10月17日与欧洲投资商Terra Firma公司旗下在泛西欧拥有1600块银幕的Odeon院线以及UCI院线签署协议,将于未来2年中在英国、爱尔兰、德国、奥地利以及葡萄牙合作安装500块数字3D银幕.     

第十二届中国建筑企业高峰论坛在绍兴市举行王治安主持会议并致辞

<正>本刊讯2014年12月23日,由中国建设报社、浙江省住房和城乡建设厅、绍兴市人民政府主办的第十二届中国建筑企业高峰论坛在绍兴市举行。来自全国各地的建筑行业主管部门、行业协会负责人,专家学者及企业代表等300余人齐聚一堂,围绕"创新融合,开放共赢"主题,共同分享了一场建筑行业思想盛宴。中国建设报社党委书记杜久才、社长翟建和中国建筑装饰协会会长李秉仁、中国土木工程协会副理事长刘     

9.3大阅兵:高标准让军魂荡气回肠

<正>阅兵是展示辉煌的时刻,而为这一辉煌采取的所有的标准,不啻也是宝贵的财富,应当成为践行标准的榜样……这个月最令人难忘、最引人自豪、最提振国威的事情,当属"9.3"大阅兵,它有着以往没有的多重的亮点:首次以纪念抗日战争暨世界反法西斯战争胜利为阅兵主题,彰显维护和平是全世界人民共同的愿望。首次邀请外国军队代表参加分列式,体现纪念大会的国际性。首次组织抗战老兵包括国民党老兵参加,体现了对历史的尊重,体现全民族抗战的特色。首次编组英模部队方队受阅,展示中国共产党在抗战中定海     

车类影视广告拍摄——光线表现篇

汽车能满足人们生活、娱乐、工作的各种需求,为生活添加乐趣.商务车、房车、越野车或轿车,不管是驰骋还是安静地停放,都具有他们独特的气质,外型、轮廓、结构、颜色、车漆的纹理及其光泽度各有特点.拍摄广告就是要把汽车的这些独到之处提炼、表达出来,在观赏者印象中建立一个全方位的立体形象,激发消费者的购买愿望,这里就必须用到一个非凡的摄影手段--光线.     

CIG前驱膜叠层方式对CIGS膜成分和结构的影响

采用中频交流磁控溅射方法制备了三种不同叠层方式的CuInGa（CIG）前驱膜。采用固态法硒化,获得了CIGS吸收层。采用SEM和XRD观察和分析了薄膜的成分、组织结构和表面形貌。着重分析不同叠层方式的CIG前驱膜对CIGs吸收层薄膜成分、晶体结构的影响。结果表明,三种叠层方式的前驱膜都可以获得成分均匀、结构一致的CIGS吸收层薄膜。Ga可以有效抑制In2Se挥发相生成,保持成分的稳定性。以CuGa（top）／CuIn（bottom）形式的前驱膜有利于形成紧密晶粒排列的CIGS。     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

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