期刊文献+
共找到6篇文章
< 1 >
每页显示 20 50 100
V,Cr掺杂CdSe铁磁半导体的电子能态密度和半金属性质研究 被引量:4
1
作者 周清 张俊峰 陈洪 《西南师范大学学报(自然科学版)》 CAS CSCD 北大核心 2006年第6期68-71,共4页
在共轭梯度近似(GGA)下,采用第一性原理平面波赝势方法,对V和Cr掺杂闪锌矿CdSe半导体的基态电子能态密度和磁性进行了研究.结果表明,掺入磁性过渡金属V和Cr后的CdSe明显具有铁磁性,每个超晶胞的总磁矩为3.0和4.0μB,而且呈现出显著的半... 在共轭梯度近似(GGA)下,采用第一性原理平面波赝势方法,对V和Cr掺杂闪锌矿CdSe半导体的基态电子能态密度和磁性进行了研究.结果表明,掺入磁性过渡金属V和Cr后的CdSe明显具有铁磁性,每个超晶胞的总磁矩为3.0和4.0μB,而且呈现出显著的半金属特征.这对在半导体工业中实现自旋载流子注入具有一定的理论价值. 展开更多
关键词 第一性原理 稀磁导体 电子能态密度 半金属相
下载PDF
V,Cr掺杂AlP稀磁半导体的电子能态密度和磁性研究
2
作者 周清 《西南大学学报(自然科学版)》 CAS CSCD 北大核心 2009年第1期27-31,共5页
在共轭梯度近似(GGA)下,采用基于密度泛函理论的第一性原理平面波赝势方法,对V,Cr掺杂闪锌矿AlP半导体的基态电子能态密度和磁性进行了研究.结果表明,掺入V和Cr后的AlP明显具有铁磁性,每个超晶胞总磁矩为2.0和3.0μB,并具有显著的半金... 在共轭梯度近似(GGA)下,采用基于密度泛函理论的第一性原理平面波赝势方法,对V,Cr掺杂闪锌矿AlP半导体的基态电子能态密度和磁性进行了研究.结果表明,掺入V和Cr后的AlP明显具有铁磁性,每个超晶胞总磁矩为2.0和3.0μB,并具有显著的半金属特征.这对在半导体工业中实现自旋载流子的注入具有一定的理论价值. 展开更多
关键词 第一性原理 稀磁导体 电子能态密度 半金属相 磁性
下载PDF
Conception of tooling adapted to thixoforging of high solid fraction hot-crack-sensitive aluminium alloys 被引量:3
3
作者 G.VANEETVELD A.RASSILI +1 位作者 J.C.PIERRET J.LECOMTE-BECKERS 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第9期1712-1718,共7页
Thixoforging is a type of semi-solid metal processing at high solid fraction (0.7<φs<1), which involves the processing of alloys in the semi-solid state.Tooling has to be adapted to this particular process to b... Thixoforging is a type of semi-solid metal processing at high solid fraction (0.7<φs<1), which involves the processing of alloys in the semi-solid state.Tooling has to be adapted to this particular process to benefit shear thinning and thixotropic behaviour of such semi-solid material.Tooling parameters, such as the forming speed and tool temperature, have to be accurately controlled because of their influence on thermal exchanges between material flow and tool.These thermal exchanges influence the high-cracking tendency and the rheology of the semi-solid material during forming, which affects parts properties and therefore their quality.Extrusion tests show how thermal exchanges influence quality of thixoforged parts made of 7075 aluminium alloys at high solid fraction by modifying process parameters like forming speed, tool temperature and tool thermal protector.Thus an optimum in terms of thermal exchanges has to be found between surface quality and mechanical properties of the part.A direct application is the evaluation of surface quality of thixoforged thin wall parts made of 7075 aluminium alloy. 展开更多
关键词 THIXOFORGING solid fraction near-net-shaping TOOLING 7075 aluminium alloys
下载PDF
Effects of Au nanoparticle size and metal-support interaction on plasmon-induced photocatalytic water oxidation 被引量:1
4
作者 Shengyang Wang Bin Zeng Can Li 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第7期1219-1227,共9页
Plasmonic photocatalysis with tunable light absorption has aroused significant attention in so-lar-to-chemical energy conversion.However,the energy conversion efficiency of plasmonic photo-catalysts is impeded by inef... Plasmonic photocatalysis with tunable light absorption has aroused significant attention in so-lar-to-chemical energy conversion.However,the energy conversion efficiency of plasmonic photo-catalysts is impeded by ineffective charge separation and the lack of highly active sites for redox reactions.In this work,the Au nanoparticle size and Au-TiO2 interaction of the Au/TiO2 plasmonic photocatalyst were adjusted simultaneously using a post-calcination treatment.The visi-ble-ight-induced water oxidation activity exhibited a volcano-like relationship with the calcination temperature;the treated photocatalyst at 600°C manifested the highest activity.Characterization with UV-visible spectra,XRD,SEM,and XPS revealed that the effect of the Au nanoparticle size and Au-TiO2 interaction were both responsible for the increase in plasmon-induced water oxidation activity. 展开更多
关键词 AU/TIO2 Water oxidation Plasmonic photocatalysis Size effect Metal-semiconductor interaction
下载PDF
组分调制Cu_3 NPd_x的大温区恒定电阻率
5
作者 纪爱玲 杜允 +2 位作者 黄娆 李超荣 曹则贤 《物理》 CAS 北大核心 2006年第11期924-926,共3页
单一固体材料的电阻率是关于温度的复杂函数.目前尚未见关于相当大的温度范围内恒定电阻率的报道;对恒电阻的需求仍然是通过材料结构组合或电路设计实现的.Cu3NPdx随组份的变化会经历半导体-半金属相变,在Cu3NPd0.238中可以在240K的温... 单一固体材料的电阻率是关于温度的复杂函数.目前尚未见关于相当大的温度范围内恒定电阻率的报道;对恒电阻的需求仍然是通过材料结构组合或电路设计实现的.Cu3NPdx随组份的变化会经历半导体-半金属相变,在Cu3NPd0.238中可以在240K的温度范围内测得不变的电阻率.这一发现至少表明大温区内恒电阻是可以在单一材料内实现的,它对固体物理的理解本身以及诸多应用都有重要的意义. 展开更多
关键词 温阻系数 Cu3NPdx 导体-半金属相 组份调制
原文传递
Fabrication of Noble metal-semiconductor hybrid nanostructures using phase transfer 被引量:3
6
作者 Tanushree Bala Ajay Singh +4 位作者 Ambarish Sanyal Catriona O'Sullivan Fathima Laffir Claudia Coughlan Kevin M. Ryan 《Nano Research》 SCIE EI CAS CSCD 2013年第2期121-130,共10页
An easy and effective solution based procedure for the synthesis of noble metal (both Au and Ag) tipped semiconductor nanomaterials is demonstrated where the metal precursors are taken in water and the semiconductor... An easy and effective solution based procedure for the synthesis of noble metal (both Au and Ag) tipped semiconductor nanomaterials is demonstrated where the metal precursors are taken in water and the semiconductors in organic medium, exploiting the phase transfer and reducing capability of suitably chosen ligands. The phase tranfer route is a generalised approach to form either Ag or Au tips on cadmium chalcogenide nanoparticles and nanorods. While multiple dots of noble metals are formed on the semiconductor nanomaterials initiall~ these coalesce into larger islands with time. The hybrids are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), photoluminescence (PL), ultraviolet-visible spectroscopy (UV-vis) and X-ray photoelectron spectroscopy (XPS). A detailed FTIR analysis was also carried out to delineate the role of the ligands in the synthesis. 展开更多
关键词 semiconductor-metalhybrids Ag tips Au tips phase transfer
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部