Frequency combinations in the magnetoresistance oscillations spectrum of a linear chain of coupled orbits with a high scattering rate

The oscillatory magnetoresistance spectrum of the organic metal (BEDO)₅Ni(CN)₄. 3C₂H₄(OH)₂ has been studied up to 50 T, in the temperature range from 1.5 K to 4.2 K. In high magnetic field, its Fermi surface corresponds to a linear chain of quasi-two-dimensional orbits coupled by magnetic breakdown (MB). The scattering rate consistently deduced from the data relevant to the basic α and the MB-induced β orbits is very large which points to a significant reduction of the chemical potential oscillation. Despite of this feature, the oscillations spectrum exhibits many frequency combinations. Their effective masses and (or) Dingle temperature are not in agreement with either the predictions of the quantum interference model or the semiclassical model of Falicov and Stachowiak.     

碳黑颗粒生长模型的初步研究

本文利用反应类(Reaction Class)概念和矩(Moment)方法,研究了层流预混甲烷火焰中碳黑颗粒的成核与长大过程。模型综合考虑了颗粒的成核、颗粒间由于碰撞的聚合、以及气态组分在颗粒表面的生长。通过数值计算预报了碳黑颗粒平均粒径、总表面积、体积分数和数密度,以及萘(A4)和乙炔(C2H2)在颗粒表面的增长速率。     

拉脱法测液体表面张力系数的改进

对拉脱法测定液体表面张力系数的实验作了改进．减小Ⅱ形框横丝长度L,减短Ⅱ形框侧丝长度b,对由此引出的自升现象、α的计算公式等问题进行了相应的分析和处理,使实验用液量由原来的100mL减为5mL,并且提高了测量准确度。     

Improving lithographic masks with the assistance of indentations

Indentations etched on the output surface of a metallic mask are proposed to produce fine lithographic patterns with a resolution of 500 nm using the finite-difference time domain(FDTD) method.Such a designed mask is capable of enhancing near field lithography(NFL) resolution more than three times compared with the structure without indentations.The simulation results show that the interference disturbance between the adjacent lithographic channels can be eliminated efficiently by employing the indentations.As a straightforward consequence,the channel-to-channel interspaces can be shortened significantly,maintaining a uniform field distribution and high contrast.     

Total Routhian Surface Calculations on Hf Isotopes

The two-dimensional total routhian surface calculations have been carried out to stud）, the triaxial superdeformed structure of a neutron-rich nucleus ^173 Hf firstly. In particular the effects of the rotational frequency ω and pairing-energy gap parameter A are discussed in detail in the course of shaping its triaxial superdeformation; additionally the neutron-shell correction energy is analyzed with emphasis in the confirmed triaxial superdeformed nucleus ^173Hf. Finally, more systematical results have been investigated for some confirmed superdeformed nuclei experimentally and a few predicted triaxial superdeformed nuclei theoretically with quadropole deformation ε2 ≈0.4 and triaxial deformation γ≈20° or 30° in the Z = 72 region.     

Flexible and accurate implementation of a binocular structured light system

This paper presents a practical implementation of a binocular system for three-dimensional (3D) surface measurement. Manufacturing procedures are easy to implement because this system does not require that the optical axes of two cameras’ lenses be coplanar and the structured light sheets be perpendicular to that plane. The method of structured light calibration is proposed to obtain the parameters of the structured light sheets. This calibration method can tolerate the surface condition of the calibration board. To eliminate the effect caused by the distortion of projector lens, each structured light sheet is fitted to a conicoid. Meanwhile, data acquired from two cameras are transformed into a unique coordinate system to avoid 3D data matching. Experiments are conducted to validate the flexibility, accuracy, and desirability of our system.     

壁面反应对微小通道内燃烧影响的数值模拟

对微小通道内氢气／空气预混火焰进行了数值模拟。通过对比考虑壁面反应和不考虑壁面反应的微通道内燃烧特性的差异,考察了壁面反应对微通道内燃烧状况的影响,揭示了壁面附近自由基行为和壁面反应、气相反应的相互关系,并探讨了不同尺度下壁面反应效应的程度。结果表明,壁面反应改变了微火焰结构,近壁面附近的自由基被吸附,在径向上出现了明...     

一种精确测量光学球面曲率半径的方法

在简要总结各种检测光学球面曲率半径方法优缺点的基础上,提出了利用激光跟踪仪和激光干涉仪测量光学球面曲率半径的新方法。首先,通过激光跟踪仪精确定位测量干涉仪出射球面波前的焦点和待测球面镜的曲率中心点坐标,再调整待测球面镜与干涉仪的相对位置,使待测球面镜达到零条纹干涉状态,用激光跟踪仪测定此时待测球面镜上多点的位置坐标,通过计算分析即可得到待测球面镜的曲率半径。研究和分析了这种测量光学球面曲率半径方法的基本原理,并提出了针对凸球面镜曲率半径的多区域测定平均综合优化的方法。结合实例对一口径为400mm的球面透镜进行了曲率半径的测量,测量得到其两面曲率半径分别为1022.283mm(凸面)和4069.568mm(凹面),并将该透镜进行了轮廓法测量对比,其相对误差都小于0.05%。     

纳米结构电学性质的静电力显微镜研究方法

纳米尺度的材料具有许多不同于宏观体材料的奇特的物理和化学特性.了解纳米结构的物性随材料尺寸及形状的变化关系,对于设计和合成具有特定功能的纳米材料有重要的指导意义.静电力显微镜技术为研究微纳米尺度下材料的电学特性提供了强有力的工具.文章介绍了这种测量技术的基本原理,并列举了几种在静电力显微镜基础上发展起来的纳米材料电学性...     

Adsorption kinetics of alkanes on TiO2 nanotubesarray - structure-activity relationship

Presented are thermal desorption spectroscopy (TDS) measurements of iso-/n-butane adsorption on a variety of TiO₂ nanotubes (TiNTs) samples which are characterized by different crystal structures. The results are compared with a prior study on anatase(0 0 1) thin films grown on SrTiO₃(0 0 1). A distinct kinetic structure-activity relationship was present, i.e., the binding energies of the alkanes depend on the polymorph (anatase vs. mixed anatase/rutile) of TiO₂. A direct-fitting procedure of the TDS data has been applied to extract the kinetics parameters. The binding energies in the limit of zero coverage decrease as anatase thin film > amorphous-TiNTs ∼ polycrystalline anatase TiNTs > polycrystalline mixed anatase/rutile TiNTs.