n型BayNixCo4-xSb12化合物的热电性能

系统地研究了Ba填充分数及Ni含量对n型BayNixCo4-xSb12(x=0—0.1,y=0—0.4)化合物热性能及电性能的影响规律.n型BayNixCo4-xSb12的热导率随Ba填充分数的增加而显著下降,当Ba填充分数为0.3时,热导率随Ni含量的增加而降低,在x=0.05时,热导率达到最小值,晶格热导率随Ni含量的增加单调降低.电子浓度和电导率随Ba填充分数及Ni含量的增加而增加,塞贝克系数则随Ba填充分数及Ni含量的增加而减小.对于Ba0.3Ni0.05Co3.95Sb12试样,得到了1.2最大 关键词： n型方钴矿 填充 置换 热电性能     

改性小麦秸秆粉/聚丙烯复合材料的性能研究

研究了碱处理(AT)、苯甲酸(BA)或/和硬脂酸(SA)改性对小麦秸秆粉(WSP)/聚丙烯(PP)复合材料(WSP/PP-CM)力学性能、热稳定性能、流变性能、润湿性能和吸水性能的影响.结果表明:碱处理可提高WSP/PP-CM的拉伸强度(TS)、弯曲强度(FS)、冲击强度(IS)、起始热分解温度(Ti)和接触角(θ),...     

单线法测量横向阻抗系统设计与模拟计算

 介绍了单线法测量横向阻抗的基本原理、系统设计和初步模拟计算结果。单线法横向阻抗测量系统由待测元件/参考元件、内置导线、导线偏移调节机构、阻抗匹配段和测量仪器构成。调节机构可以精确调整内置导线的横向位置以激励偶极模式。利用微波工作室软件模拟计算待测元件（2 856 MHz“凸型”腔）的偶极模。“凸型”腔横向阻抗的幅值和偶极模频率的计算结果与ABCI程序数值计算的结果基本相符,说明了单线法横向阻抗测量系统理论上的可行性。     

Origin of the metallic to insulating transition of an epitaxial Bi(111) film grown on Si(111)

Transport characteristics of single crystal bismuth films on Si(111)-7×7 are found to be metallic or insulating at temperatures below or above T_C, respectively. The transition temperature T_C decreases as the film thickness increases. By combining thickness dependence of the films resistivity, we find the insulating behaviour results from the states inside film, while the metallic behaviour originates from the interface states. We show that quantum size effect in a Bi film, such as the semimetal-to-semiconductor transition, is only observable at a temperature higher than T_C.     

纳米金属催化在偶联反应中的应用*

在过去的一二十年里,纳米材料科学的发展主要集中在纳米材料的合成,结构的修饰与表征以及相应的物理性质,而纳米材料在有机反应中的催化还未受到应用的重视。最近具有大的表面积和高反应活性的纳米形态受到广泛的关注。利用晶型的纳米金属粒子作为催化剂在有机合成领域得到了越来越多的应用,本综述主要概括了各种金属纳米粒子在偶联反应中的应用,包括C-C键、C-N键、C-O键和C-S键的形成。     

Modulation instability of femtosecond pulses in fibres with slowly decreasing dispersion

In this paper,we investigate the modulation instability for generating femtosecond pulses in fibres with slowly decreasing dispersion.Higher-order dispersion and higher-order nonlinear effects are taken into account when the continuous wave or quasi-continuous wave evolves into sub-picosecond and femtosecond pulses by modulation instability in the optical fibres.Our research results show that the gain spectrum of the dispersion-decreasing fibres is much wider than that in conventional fibres.The third-order dispersion effect has no contribution to gain spectrum,while the self-steepening effect reduces the maximum value and gain bandwidth,and the Raman self-scattering effect widens the extent to which the modulation instability occurs.     

Study of surface cell Madelung constant and surface free energy of nanosized crystal grain

Surface cell Madelung constant is firstly defined for calculating the surface free energy of nanosized crystal grains, which explains the physical performance of small crystals and may be greatly beneficial to the analysis of surface states and the study of the dynamics of crystal nucleation and growth. A new approximative expression of the surface energy and relevant thermodynamic data are used in this calculation. New formula and computing method for calculating the Madelung constant α of any complex crystals are proposed, and the surface free energies and surface electrostatic energies of nanosized crystal grains and the Madelung constant of some complex crystals are theoretically calculated in this paper. The surface free energy of nanosized-crystal-grain TiO₂ and the surface electrostatic energy(absolute value) of nanosized-crystal-grain α -Al₂O₃ are found to be the biggest among all the crystal grains including those of other species.     

Tb（Ⅲ）—ARS—CTMAB络合物的极谱吸附波研究

研究了在 p H9.4的氨 -氯化铵缓冲溶液中 ,Tb( )与茜素红 (ARS)、溴化十六烷基三甲铵 (CTMAB)三元络合物的极谱波 ,该极谱波峰电位在 - 0 .74V(vs.SCE) ,峰高与铽的浓度在6.0× 1 0 -8～ 8.0× 1 0 -6mol· L-1之间呈线性关系 ,检出限为 4.0× 1 0 -8mol· L-1,结合萃取柱色谱分离方法测定了稀土矿石中的重稀土元素铽。     

乙酰丙酮分光光度法测定水性涂料及胶粘剂中的甲醛含量

建立测定水性涂料和胶粘剂中甲醛含量的乙酰丙酮分光光度法。测定甲醛的线性范围为0．00～80.29μg,相关系数为0．9999,水性涂料和胶粘剂样品中甲醛含量测定结果的相对标准偏差分别为3．2％、2.8％,回收率分别为89％～93％、90％～96％。     

Approximate solution to a class of multivalued nonlinear mixed variational inclusions

IntroductionIn recent years,the theory of variational inclusion has appeared as an elegant andfascinating branch of pure and applied mathematics.This theory provides us with a convenientmathematical apparatus for uniformly studying a wide range of problem…