排序方式: 共有65条查询结果,搜索用时 8 毫秒
31.
吴银忠 《常熟理工学院学报》2001,15(4):16-18
应用改进的有效媒体理论研究了铁电-聚合物颗粒复合材料的热电性质,当颗粒浓度在渗流阈值附近时,界面效应非常重要。因此,在有效媒体理论中,考虑到颗粒的界面效应,得到了铁电颗粒复合材料的热电系数在渗流阈值附近有一陡增,这与实验中观察到的现象一致。 相似文献
32.
Stress equilibrium equations, boundary- and continuity-conditions were used to establish a theoretical model of progressive debonding with friction at the debonded interface. On a basis of the minimum complementary energy principle, an expression for the energy release rate G was derived to explore the interfacial fracture properties. An interfacial debonding criterion G≥Гi was introduced to determine the critical debond length and the bridging law. Numerical calculation results for fiber-reinforced composite SCS-6/Ti-6Al-4V were compared with those obtained by using the shear-lag models. 相似文献
33.
纳米科学技术是一门跨学科、跨行业的高新科学技术,由于纳米材料体系具有许多独特的性质,应用前景广阔,因而近几年来发展迅速。本文对高分子纳米复合材料的制备方法作了简介。 相似文献
34.
基于Lamb波在各向异性材料的波动方程和频散原理,采用斜入射法激发A0模态兰姆波。针对板材的铺层角度、各接收点方向和频厚积等因素对衰减规律和传播速度规律有较大影响,采用有限元软件建立玻璃钢复合材料层合板模型,对各影响因素进行数值模拟研究。研究表明:Lamb波传播特性与纤维铺层方式有关,声速及衰减特性沿纤维方向和非纤维方向传播声速和衰减差异较大,并且呈对称现象,频厚积在0.6~1.8 MHz·mm,对传播声速和衰减影响为线性下降且趋于平稳。 相似文献
35.
为了研究钢筋增强ECC梁受弯性能,进行了钢筋增强ECC梁和普通钢筋混凝土梁受弯的对比研究.结果表明,相比普通钢筋混凝土梁,钢筋增强ECC梁的受弯承载力和延性分别提高了24.8%和187.76%,并且在梁中用ECC代替混凝土可有效延缓裂缝的发展.此外,采用简化的ECC本构模型对钢筋增强ECC及混凝土梁的受弯性能进行了非线性有限元分析,模拟结果与试验结果吻合较好,在服役期间钢筋增强ECC梁的裂缝可以控制在0.4 mm以下.ECC材料的使用可明显提高梁的抗弯承载力、变形能力、延性等受弯性能. 相似文献
36.
为探索新的钨骨架烧结工艺以降低骨架的烧结温度和提高钨铜复合材料的性能,并在工业上实现批量生产,采用添加蓝钨的还原烧结工艺制备钨骨架,并对添加蓝钨烧结钨骨架的机理进行探讨.采用扫描电镜、激光热导仪和化学成分分析仪对钨铜复合材料的组织、热导率、氧含量进行了分析.结果表明:用该方法制备的钨骨架含氧量低,熔渗后W-26Cu组织致密度大于99%,热导率可达231W/(m·K). 相似文献
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38.
Ghinea R Ugarte-Alvan L Yebra A Pecho OE Paravina RD Perez Mdel M 《Journal of Zhejiang University. Science. B》2011,12(7):552-562
This study deals with the influence of surface roughness on the color of resin composites. Ten resin composites (microfilled,
hybrid, and microhybrid) were each polished with 500-grit, 1 200-grit, 2 000-grit, and 4 000-grit SiC papers. The roughness
parameter (R
a) was measured using a Plμ confocal microscope, and field-emission scanning electron microscope (Fe-SEM) images were used
to investigate filler morphology. Color was measured using a spectroradiometer and a D65 standard illuminant (geometry diffuse/0°
specular component excluded (SCE) mode). Surface roughness decreased with grit number and was not influenced by filler size
or size distribution. A significant influence of R
a on lightness (L*) was found. Lightness increased with decreases in roughness, except for specimens that underwent polishing procedure 4 (PP4;
500-grit, 1 200-grit, 2 000-grit, and 4 000-grit SiC papers consecutively). Generally, it was found that surface roughness
influenced the color of resin composites. The composites that underwent PP1 (500-grit SiC paper) exhibited significant differences
in chroma (C*), hue (h°), and lightness (L*) compared to composites that underwent PP3 (500-grit, 1 200-grit, and 2 000-grit SiC papers consecutively) and PP4. Color
difference (ΔE*) between the polishing procedures was within acceptability thresholds in dentistry. 相似文献
39.
FRP复合材料加固混凝土结构新技术研究进展 总被引:13,自引:5,他引:13
近十多年来,国内外对FRP加固(包括改造、修复)混凝土结构这一新技术进行了广泛的试验和理论研究,简要论述了这一新技术的研究进展,着重论述受弯构件加固后的破坏形式和承载力计算方法,包括梁的抗弯加固、梁的抗剪加固和板的抗弯加固等,供实际工程应用参考。 相似文献
40.