两相颗粒多孔材料导热系数研究

对固-气两相颗粒多孔材料导热系数的预测,尚未见以实验数据对其各预测模型进行分析及验证其准确度的相关文献。本文利用断电热线法测定石英砂、碳化硅、工程沙以及煤灰的导热系数;将模型预测结果与实验数据进行对比分析,结果表明,Kunii and Smith模型误差小;考虑孔隙率的影响,利用实测数据对Kunii and Smith模型进行修正,给出新的预测模型;通过与国外学者给出的实测导热系数的对比,验证了本文给出的修正模型的准确性。     

Conduction of Strongly Coupled Electrons Through Narrow Channels on Liquid Helium Surface: Simulation

The conduction of electrons through narrow channels formed on the surface of liquid helium is analyzed by numerical simulations. It is shown that, when electrons are strongly coupled, we have nonlinear and even negative dependence of conductance on the width of the constriction which is controlled by the gate voltage (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Intermodulation of transverse magnetoresistance oscillations in structures with strong intersubband interaction

In the Shubnikov–de Haas oscillation spectrum of doped InAs/AlSb structures, high-amplitude peaks are established at combination frequencies. It is demonstrated that they are caused by a significant contribution of intersubband scattering to the processes of electron-electron interaction. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 32–38, December, 2008.     

Hot carrier relaxation in InP and GaAs on a subpicosecond time scale

Hot carrier relaxation in InP and GaAs is investigated in a comparative study using three different time resolved optical techniques. At carrier densities between 10¹⁷ to 10¹⁸ cm⁻³ in both materials the relaxation is strongly influenced by carrier-carrier-scattering. Internal thermalization of electrons and holes occurs on a femtosecond time scale comparable to the duration of the excitation. The temperatures of electrons and holes, however, remain different on a time scale of picoseconds.     

基于微处理器的遥控水热毯控制系统设计

介绍了一种水热毯的新型控制系统,以AT89C52单片机为核心,配合ADC0809芯片,用双向可控硅控制加热片的工作.系统软件用C语言编制,实现了温度在一定范围内连续可调、定时启/闭、被窝预热等功能.实现了温度智能控制,其温度和定时时间均可在液晶屏上显示.红外遥控电路主芯片采用PT262/PT2272遥控编解码芯片.遥控器的引入实现了系统的远距离控制.     

Acoustic timescale characterisation of symmetric and asymmetric multidimensional hot spots

In this work, two-dimensional hot spots are modelled by combining a linear temperature gradient with a constant temperature plateau. This approach retains the simplicity of a linear temperature gradient, but captures the effects of a local temperature maximum of finite size. Symmetric and asymmetric plateau regions are modelled using both rectangular and elliptical geometries. A one-step Arrhenius reaction for H₂–air is used to model the reactive mixture. Plateaus with different ratios of excitation to acoustic timescales, spanning two orders of magnitude, are simulated. Even with clear differences in behaviour between one and two dimensions, the a priori prescribed hot spot timescale ratio is shown to characterise the 2-D gasdynamic response. The relationship between one and two dimensions is explored using asymmetric plateau regions. It is shown that 1-D behaviour is recovered over a finite time. Furthermore, the duration of this 1-D behaviour is directly related to the asymmetry of the plateau.     

陶瓷过滤器高温除尘技术的研究进展

对陶瓷过滤元件及结构、滤饼的作用和架桥、过滤器故障安全（CPP）系统及陶瓷过滤器高温气体净化一体化技术等几个方面进行了评述，总结了陶瓷过滤器存在着过滤管破裂、清灰效率下降、管板和器壁的连接及脉冲阀的长期稳定性等几个问题，指出新型陶瓷材料的研究和陶瓷过滤器高温气体净化一体化技术是陶瓷过滤器今后的研究方向．     

开态热载流子应力下的n-MOSFETs的氧化层厚度效应

在最大衬底电流条件下(Vg=Vd/2),研究了不同氧化层厚度的表面沟道n-MOSFETs在热载流子应力下的退化.结果表明, Hu的寿命预测模型的两个关键参数m与n氧化层厚度有着密切关系.此外,和有着线性关系,尽管不同的氧化层厚度会引起不同的模型参数,但是如果对于不同厚度的氧化层,采用不同的m与n,Hu的模型仍然成立.在这个结果的基础上,Hu的寿命预测模型能用于更薄的氧化层.     

Theory of non-linear transport in quantum waveguides

The equations for quantum ballistic transport in inhomogeneous quantum wire structures are transformed into a set of one-dimensional coupled mode equations where the coupling parameters are explicitly dependent on the shape parameters for the confinement potential. In the adiabatic approximation or in the extreme quantum limit the resulting motion is governed by an effective Hamiltonian which contains the influence of quasi-electric fields and quasi-momentum dependent forces which arise from the inhomogeneous shape parameter variation along the quantum waveguide. The subsequent transport may be described by a Boltzmann-like kinetic equation and hot-electron effects arising from variations in the waveguide profile are predicted. It is shown that transport through a wide region of an otherwise narrow wire leads to multiply-connected electron paths which will produce Aharonov-Bohm resonances. The analytical formalism is underpinned by a new numerical method suitable for 3-D studies based on representing the inhomogeneous waveguide by an equivalent network of one-dimensional wires.