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Behaviour of nitrided layers subjected to influence of hydrogen
Corrosion Plasma nitriding Hydrogen permeation and uptake Hydrogen embrittlement
2010/5/1
High-strength steels may exhibit severe loss of ductility, toughness and strength due to hydrogen embrittlement (HE), resulting in sudden fracture or delayed failure. The susceptibility of steels to H...
Nanomechanical properties of silicon surfaces nanostructured by excimer laser
Nanomechanical properties silicon surfaces nanostructured excimer laser
2010/4/30
Excimer laser irradiation at ambient temperature has been employed to produce nanostructured silicon surfaces. Nanoindentation was used to investigate the nanomechanical properties of the deformed sur...
以稀土氧化物、硝酸铝和硼酸为原料, 用高温球磨法制备红色荧光粉YAl3(BO3)4:Eu3+, 研究其结构、形貌和发光性能。结果表明, 在700℃高温球磨制备YAl3(BO3)4:Eu3+荧光粉, 煅烧温度比硝酸盐分解法降低200℃, 比高温固相法降低500℃; 制备出的荧光粉粒度分布均匀, 晶粒近似呈球状, 尺寸为纳米级; 在394 nm的紫外光激发下YAl3(BO3)4:Eu3+荧光粉具有较好...
以硅胶(SiO2) 和聚苯乙烯--丙烯酸(PSA)为原料制备SiO2/PSA核壳结构型复合粒子。在相转化法制备聚合物薄膜的基础上, 为避免粒子团聚提出以蒸汽方式代替传统的液滴方式, 将非溶剂缓慢而均匀地加入SiO2与PSA溶液的混合物中。采用红外光谱、扫描电子显微镜、激光粒度分析仪、热重分析、压汞仪和氮气吸附/脱附等方法对粒子的化学组成、形貌、粒径分布以及多孔结构特性作了分析和表征。结果表明, S...
机械合金化和放电等离子烧结制备AgPbSbTe热电材料
无机非金属材料 热电材料 机械合金化 放电等离子烧结
2010/4/25
采用机械合金化和放电等离子烧结方法制备高性能AgPbSbTe热电材料, 研究了制备工艺对材料热电性能的影响。结果表明, 材料的物相组成和热电性能都受到机械合金化时间的影响; 适当地控制放电等离子烧结工艺可以抑制晶粒长大, 增加晶界散射, 降低热导率。实验中得到AgPbSbTe热电材料的最大功率因子为18 μW/K2cm, 最小热导率为1.1 W/m K。机械合金化(球磨4 h、转速350 r/m)...
用元素分析、X射线衍射和拉曼光谱等手段对不同结构成分的石墨纤维进行表征, 研究了石墨结构与纤维中氮的关系。结果表明：在高温石墨化过程中, 随着氮的减少, 石墨微晶堆叠厚度和宽度不断增大, 纤维的晶区取向度和石墨化度提高。 氮含量大于0.08%时, 石墨片层中有氮原子的位置会扭曲变形, 不利于石墨微晶的生长, 石墨微晶大小、晶区取向度及石墨化度增长比较缓慢； 当氮元素含量小于0.08%时, 由氮引起...
建立三个Cr掺杂TiO2模型并计算了其电子结构。根据这些模型得到了相似的计算结果：掺杂Cr在TiO2的禁带中引入带宽约为1.0 eV的中间能级，使其具有可见光响应特性。但是过多的Cr会成为光生电子--空穴对的复合中心，使掺杂TiO2的光催化性能下降。在此基础上采用水热法制备了具有不同名义Cr掺杂浓度的纳米TiO2粉体。结果表明，所制备的Cr掺杂纳米TiO2均为锐钛矿型，比表面积为178--221 ...
采用纳米压痕技术研究了不同龄期水泥硬化浆体中水化硅酸钙(C--S--H)凝胶的微观弹塑性和徐变特性。结果表明, 随着龄期的增长, C--S--H凝胶在相同荷载作用下的弹性能逐渐减小, 并趋于稳定值, 且低密度C--S--H凝胶的弹性能均高于同龄期的高密度C--S--H凝胶。对于相同的荷载和持荷时间, 高密度C--S--H凝胶的徐变显著低于同龄期低密度C--S--H凝胶。应用纳米压痕技术从微观层面测...
A comparative approach to modelling of hard tissues
CAD Modelling Manufacturing Customized Implant
2010/4/2
In recent years biomedical engineering has opened a new window to CAD and this technology has been extensively used in many application areas. Among these, modelling hard tissues has been of interest ...
在乙醇—水溶液体系中，在无模板剂的情况下，水热合成由纳米棒自组装成的独特海胆状薄水铝石(AlOOH)超结构。采用XRD、SEM、TEM和SAED对其物相结构和形貌进行了分析，讨论了铝盐前驱体、醇水比例和反应温度对产物形貌的影响。研究结果表明：当铝盐前驱体为AlCl3•6H2O，醇水体积比为1:2，反应温度为200 ℃时，得到形貌规则、分散均匀的三维海胆状薄水铝石超结构，该海胆状超结构是...
Trend report on international and Japanese standardization activities for bioceramics and tissue engineered medical products
Trend report international Japanese standardization activities for bioceramics tissue engineered medical products
2010/2/28
Since porous and injectable bioceramics have recently been utilized often as scaffolds for bone regenerative medicine, the need for their standardization has increased. One of the standard proposals i...
Stem cell technology using bioceramics: hard tissue regeneration towards clinical application
Stem cell technology bioceramics hard tissue regeneration towards clinical application
2010/2/28
Mesenchymal stem cells (MSCs) are adult stem cells which show differentiation capabilities toward various cell lineages. We have already used MSCs for treatments of osteoarthritis, bone necrosis and b...
Structure, thermal and magnetic properties of Fe43Co14Ni14B20Si5Nb4 bulk metallic glass
Structure thermal magnetic properties Fe43Co14Ni14B20Si5Nb4 bulk metallic glass
2010/2/12
Iron-based metallic glasses have received great attention of researchers, because of their good magnetic, mechanical properties and corrosion resistance. Moreover, these alloys are potential candidate...
FEM applications to model friction processes in plastic strain conditions
Analysis and modelling CAD/CAM Process Systems Design FEM analysis Tribo-meter
2010/2/2
One of the basic problems in different aspects of movement is the determination of frictional resistance occurring in the analyzed friction node. Plastic working processes are also included in such ge...
Dielectric spectroscopy study of Ba0.98Na0.02Ti0.98Nb0.02O3 ceramic
Ceramics Phase transitions Ferroelectrics
2010/1/11
The dielectric spectroscopy method was applied to measure frequency and temperature dependence of complex dielectric permittivity, complex admittance, phase angle. The frequency dependence of ac condu...