电磁场中载流薄板的弯曲行为分析

在建立载流薄板的非线性磁弹性运动方程、电动力学方程和Lorentz力表达式的基础上,通过变量代换,将描述薄板的磁弹性状态方程整理成含有10个基本函数的标准Cauchy型.采用差分法及准线性化方法,将标准Cauchy型非线性偏微分方程组,变换成为能够用离散正交法求解的准线性微分方程组.通过算例,得到了电磁场与机械载荷联合...     

Collision efficiency of two nanoparticles with different diameters in Brownian coagulation

The collision efficiency of two nanoparticles with different diameters in the Brownian coagulation is investigated. The collision equations are solved to obtain the collision efficiency for the dioctyl phthalate nanoparticle with the diameter changing from 100 nm to 750 nm in the presence of the van der Waals force and the elastic deformation force. It is found that the collision efficiency decreases as a whole with the increase of both the particle diameter and the radius ratio of two particles. There exists an abrupt increase in the collision efficiency when the particle diameter is equal to 550 nm. Finally, a new expression is presented for the collision efficiency of two nanoparticles with different diameters.     

Orientation distribution of fibres in a channel flow of fibre suspension

The orientation and concentration distributions of fibres in laminar and turbulent channel flows are investigated numerically. The obtained results are in good agreement with the experimental data. In the laminar flow regime, more fibres orient to the flow direction as the Reynolds number increases. The shear rate of fluid around a fibre plays an important role in determining the orientation distribution of fibres, while the fibre density and the fibre aspect-ratio have marginal influence on the orientation distribution. In the turbulent regime, the orientation distribution of fibres becomes more homogeneous with the increase of Reynolds number, and the concentration profile is flatter than that in the laminar regime. The fluctuating intensity of fibre velocity in the downstream direction is larger than that in the lateral directions.     

Optical and mechanical properties of hollow-core fibers with cobweb cladding structure

This paper explores the possibility of realizing a hollow-core optical fiber, whose cladding is composed of cylindrical alternating layers of air and high-index material with supporting structure. The optical properties and the design criteria of the proposed fiber are evaluated by the compact two-dimensional (2D) finite-difference time-domain (FDTD) method. In particular, the influence of the number and width of supporting strips on the leakage loss of the fiber is investigated. Furthermore, the mechanical performances of the fiber are estimated by finite-element method, confirming that hollow-core fibers with a reasonable size and number of supporting strips are reliable.     

过模介质O-波导的传播特性

本文详细分析了过模介质O-波导的全部模式,提出一种简单准确的模式分类法,导出了各本征模分离的特征方程,避免了直接求解复杂的特征方程。讨论了按场分布划分的三类正规模:表面模、界面模和泄漏模以及它们的传播特性,给出了相应的近似解。几个极限结果与文献十分吻合。研究表明,适当选择过模介质O-波导的材料参数和波导尺寸,它的传播特性很容易控制。     

低能氘分子团（d^＋3）与固体靶原子相互作用过程中的团簇 …

通过对三个氘原子组成的氘分子团与三个分立的氘原子在轰击固体靶原子时所激发以Ｘ射线产额的差别的研究，进而揭示氘分了团在以库仑激发方式与靶原子相互作和中所体现出的团簇优势，实验结果显示，在１０－１００ｋｅＶ／ｄ能区，每个分子团中的氘核所激发的Ｘ射线产额平均为相同能量的普通氘核所估激发的Ｘ射线产额的２．５倍，而且该比值具有较高很弱的能量相关性，基于原子库仑相互作用规律对实验现象做了初步解释和简要估算，提     

从1/2+1/3=2/5引发的思考

我国的一位学者有一次到国外去考察,听了一堂洋教师的分数加法课.在课堂上,老师首先提问学生21 13等于多少?不一会儿,许多学生纷纷站起来回答:12 31=25.然后,老师又问其余的学生,你们有不同意见吗?其余学生都说没有.这时老师便说:“那好!就让21 13等于52吧!这就是分数的加法,…     

零温物态方程输入参数B0K、B′0K和ρ0K的确定

在对Grtineisen系数高温高压下演化特性不作任何假设的前提下，建立了一种不依赖于等温物态方程具体形式，通过Hugoniot实验数据直接确定0K零压等温体积模量B0K及其对压力的一阶导数B′0k。和初始密度ρ0K等0K物态方程输入参数的方法。通过与实验和理论数据的分析和比较，表明用这一方法确定的．B0K和B′0k不仅合理，而且具有很高的精度，特别是B′0k的精度，要优于目前传统超声实验的测量精度。此外，这一方法所确定的ρ0K不仅在Grtineisen物态方程的框架内与相应的室温零压特性参数相适配，而且与低温热膨胀实验数据所确定的近0K初始密度ρ0E非常吻合。     

TWO POSITIVE SOLUTIONS FOR A CLASS OF SINGULAR BOUNDARY VALUE PROBLEMS

An existence theorem of two positive solutions of the singular BVP1/(p(t))(p(t)y′(t))′+λα(t)f(y(t))=0,t∈(0,1),αy(0)-βp(t)y′(t)=0=γy(1)+δp(t)y′(t)was established by using topological degree theory.     

扭秤周期法测量万有引力常数G

在华中理工大学引力实验中心的山洞实验室进行了扭秤周期法测量万有引力常数G的实验 .初步的实验结果为G =( 6 .6 6 90± 0 .0 0 1 6 )× 1 0 ^-11m³ ·kg^-1·s^-2 ,其相对精度为 240× 1 0 ^-6.这一结果在3σ范围内与1986年Cohen和Taylor给出的平均值相吻合 .