期刊文献+
共找到7篇文章
< 1 >
每页显示 20 50 100
超音速下梯形复合材料层合板的气动热弹性 被引量:1
1
作者 蒋国庆 李凤明 《科学技术与工程》 北大核心 2017年第28期1-8,共8页
发展了有限元方法,对超音速环境中梯形复合材料层合板的气动热弹性问题进行了研究。考虑可压缩流和斜激波的影响,采用一阶活塞理论表示气动压力。针对复合材料层合板的不规则结构,以及板由于气动加热而产生的复杂温度分布,利用有限单元... 发展了有限元方法,对超音速环境中梯形复合材料层合板的气动热弹性问题进行了研究。考虑可压缩流和斜激波的影响,采用一阶活塞理论表示气动压力。针对复合材料层合板的不规则结构,以及板由于气动加热而产生的复杂温度分布,利用有限单元法,建立梯形复合材料层合板的热传导方程和气动热弹性耦合运动方程。通过热传导方程得到板的温度分布,再结合气动热弹性运动方程分析梯形板的气动热弹性特性。通过数值计算,研究气动加热和铺设角对超音速下梯形板的固有频率和模态的影响。 展开更多
关键词 气动热弹性 梯形复合材料层合板 有限元分析 模态分析 颤振
下载PDF
梯形结构铜氧化合物(Sr,Ca)_(14)Cu_(24)O_(41)空穴分布研究
2
作者 张勃 叶林晖 韩汝珊 《低温与超导》 CAS CSCD 北大核心 1997年第4期35-40,共6页
在离子模型下通过计算单胞的马德隆能,探讨了(Sr,Ca)14C424O41化合物中可能的空穴分布,结果表明空穴集中在CuO2链层,与SACater[1]等的磁化率实验结果一致。类似地我们计算了在施压和氧含量有偏离情况下的空穴分布:没有发现空穴... 在离子模型下通过计算单胞的马德隆能,探讨了(Sr,Ca)14C424O41化合物中可能的空穴分布,结果表明空穴集中在CuO2链层,与SACater[1]等的磁化率实验结果一致。类似地我们计算了在施压和氧含量有偏离情况下的空穴分布:没有发现空穴的转移。 展开更多
关键词 铜氧化物 梯形材料 马德隆起 高温超导 空穴结构
下载PDF
填料协同增强增韧光固化树脂基口腔材料的制备、性能及生物力学评价 被引量:8
3
作者 罗毅 蒋俊强 但洪平 《中国组织工程研究》 CAS 北大核心 2017年第10期1489-1494,共6页
背景:光固化复合树脂由于色泽美观、优良的物理、化学性能及操作简单等在牙科缺损修复中得到应用。但是,复合树脂由于力学性能不足容易引起复合体折断,导致临床使用难以达到预期治疗效果。目的:探讨填料协同增强增韧光固化树脂基口腔材... 背景:光固化复合树脂由于色泽美观、优良的物理、化学性能及操作简单等在牙科缺损修复中得到应用。但是,复合树脂由于力学性能不足容易引起复合体折断,导致临床使用难以达到预期治疗效果。目的:探讨填料协同增强增韧光固化树脂基口腔材料的制备方法、性能及生物力学特征。方法:以原子转移自由基聚合方法对纳米二氧化硅进行表面接枝聚甲基丙烯酸甲酯(SiO_2-PMMA)改性,获得接枝SiO_2-PMMA,利用同轴静电纺丝方法制备聚丙烯腈/聚甲基丙烯酸甲酯核-壳纳米纤维,以铜网作为接收装置获得具备网格结构的二维乳酸-羟基乙酸共聚物纳米纤维膜。以硅烷偶联剂为原乙酯前驱体溶胶-沉淀法制备多尺度、多维度填料,采用硅烷偶联剂进行改性。将接枝SiO_2-PMMA核-壳纳米纤维、梯形聚硅氧烷材料与光固化树脂基体进行复合,比较两种复合树脂材料的力学性能、体积收缩率、毒性、降解性能等。结果与结论:(1)复合树脂断裂形貌的电镜表征:填料接枝SiO_2-PMMA核-壳纳米纤维在光固化树脂基体中能较好的分散,团聚现象相对较少,存在单分散现象;而梯形聚硅氧烷材料在光固化树脂基体中分散不均匀,且在复合树脂中甚至出现团聚现象;(2)弯曲强度、弯曲模量及断裂功:填料接枝SiO_2-PMMA核-壳纳米纤维光固化树脂基口腔材料的弯曲强度、弯曲模量及断裂功显著高于梯形聚硅氧烷材料光固化树脂基口腔材料(P<0.05);(3)体积收缩率:填料接枝Si O2-PMMA核-壳纳米纤维光固化树脂基口腔材料的体积收缩率低于梯形聚硅氧烷材料光固化树脂基口腔材料(P<0.05);(4)性能测定:填料接枝Si O2-PMMA核-壳纳米纤维光固化树脂基口腔材料吸水性及细胞毒性A值高于梯形聚硅氧烷材料光固化树脂基口腔材料(P<0.05),而溶解值低于梯形聚硅氧烷材料光固化树脂基口腔材料(P<0.05);(5)提示制备的填料协同增强增韧光固化树脂基口腔材料具备优良的性能和生物力学特征。 展开更多
关键词 生物材料 口腔生物材料 光固化树脂 生物力学 二氧化硅 聚甲基丙烯酸甲酯 梯形聚硅氧烷材料
下载PDF
Microstructure and mechanical properties of TA15/TC11 graded structural material by wire arc additive manufacturing process 被引量:7
4
作者 He WANG Shu-yuan MA +2 位作者 Jia-chen WANG Tao LU Chang-meng LIU 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第8期2323-2335,共13页
A graded structural material(GSM)with a material transition from TA15 to TC11 was fabricated by wire arc additive manufacturing(WAAM)method.The grain morphology,chemical composition,microstructure and mechanical prope... A graded structural material(GSM)with a material transition from TA15 to TC11 was fabricated by wire arc additive manufacturing(WAAM)method.The grain morphology,chemical composition,microstructure and mechanical properties of the as-deposited GSM were all characterized to investigate their variations along the deposition direction.The results indicate that from TA15 to TC11,the grain size decreases and a transition from columnar grains to equiaxed grains occurs.The content of alloy element alters greatly within a short distance,and the width of the mutation zone is 800μm.Both TA15 and TC11 regions exhibit basketweave microstructure withα-phase andβ-phase.However,during the transition from TA15 to TC11,theα-lath becomes fine,which leads to an increase in microhardness.The tensile test shows that the bonding strength at the interface is higher than the longitudinal strength of TA15,and the lateral elongation at the interface is higher than that of TA15 and TC11. 展开更多
关键词 wire arc additive manufacturing graded structural material grain morphology microstructure mechanical properties
下载PDF
Apparently Negative Electric Polarization in Shaped Graded Dielectric Materials
5
作者 范春珍 高银浩 +1 位作者 高勇 黄吉平 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第5期913-919,共7页
By using a first-principles approach, we investigate the pathway of electric displacement fields in shaped graded dielectric materials existing in the form of cloaks with various shapes. We reveal a type of apparently... By using a first-principles approach, we investigate the pathway of electric displacement fields in shaped graded dielectric materials existing in the form of cloaks with various shapes. We reveal a type of apparently negative electric polarization (ANEP), which is due to a symmetric oscillation of the paired electric permittivities, satisfying a sum rule. The ANEP does not occur for a spherical cloak, but appears up to maximum as a/b (the ratio between the long and short principal axis of the spheroidal cloak) is about 5/2, and eventually disappears as a/b becomes large enough corresponding to a rod-like shape. Further, the cloaking efficiency is calculated for different geometrical shapes and demonstrated to closely relate to the ANEP. The possibility of experiments is discussed. This work has relevance to dielectric shielding based on shaped graded dielectric materials. 展开更多
关键词 shaped graded materials negative electric polarization electric displacement fields
下载PDF
Analysis of the Deformation of Composite Materials of Scrapes of Tire and Latex with Temperature Variation
6
作者 Elmo Thiago Lins Coeuras Ford Rubens Maribondo do Nascimento +2 位作者 Jose Ubiragi de Lima Mendes Antonio Torres Marques Celeste Margarida Correia Pereira 《Journal of Chemistry and Chemical Engineering》 2012年第1期39-47,共9页
The great major applications of thermal isolation are in the strip of drops and averages temperatures (up to 180 ℃), which is used from aggressive materials to the nature, such as glass wool, rock wool, polystyrene... The great major applications of thermal isolation are in the strip of drops and averages temperatures (up to 180 ℃), which is used from aggressive materials to the nature, such as glass wool, rock wool, polystyrene, EPS among others. In spite of the effectiveness in the retention of the flow of heat, such materials possess considerable cost and they are discarded for long years to be decomposed. In that context, to adapt to the world politics about the preservation of the environment, a study began with intention of developing a material composite with thermal properties, originating from insulating industrial residues. In this research, the behavior of this composite was analyzed, when it submitted traction efforts. For this, a term-mechanic was used (DMA), where the composite was differentiated under variation temperatures. It was also certain that the gradient temperature of the composite was the source of heat, the conductivity and thermal diffusion. Consequently, the function of the answers of the system was possible to be observed with the deformation of the composite with the tension and temperature variation, as well as the temperature gradient for each proportion of the composite. 展开更多
关键词 COMPOSITE LATEX deformation.
下载PDF
Study on the Manufacturing Technology of Directly Metal Forming based on Overlay Welding
7
作者 Limin Zhang 《International Journal of Technology Management》 2014年第7期16-17,共2页
Rapid prototyping technology can greatly improve the actual processing industrial prototype; this paper introduces the main principle, characteristics and technology of rapid prototype manufacturing. The current rapid... Rapid prototyping technology can greatly improve the actual processing industrial prototype; this paper introduces the main principle, characteristics and technology of rapid prototype manufacturing. The current rapid prototype manufacturing products and production problems are analyzed. Because of the direct metal forming process have the characteristic of point by point, surfacing with stack molding manufacturing layer by layer, so it is suitable for complex shape parts two-dimensional or three-dimensional functionally gradient materials manufacturing. 展开更多
关键词 Layer accumulation model gradient material direct metal forming
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部