Temperature Dependence of Thermal Emission Rate in Cr:GaAs

The new method of measuring the ratio of thermal emission rate to the photoexcitation constant os presented.The temperature dependence of the ratio for Cr:GaAs is calculated by using the previously published data of two- wave mixing,Results show that the calculating data and previous phenmenological theoretic ones coincide with each other very well.     

Photons in the Non－uniform Optical Waveguide Propagate along z－axis in Spiral Form

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VECTOR WAVE FUNCTION EXPANSION FOR SOLVING ELECTROMAGNETIC SCATTERING BY BURIED OBJECTS

An analysis of solving the electromagnetic scattering by buried objects using vectorwave function expansion is presented.For expanding the boundary conditions both on the planarair-earth interface and on the spherical surface,the conversion relations between the cylindricaland spherical vector wave functions are derived.Hence the vector wave function expansion isconveniently applied to solve this complex boundary-value problem.For the excitation of the in-cident plane wave and the dipole above the earth,the scatterlng patterns of the buried conductingand dielectric spheres are presented and discussed.     

采用边界元法研究槽形波导的色散特性

本文提出了用边界元法分析槽形波导的方法。推导出了有关表达式,并对一典型例子进行了研究,计算了其色散特性;得到的数据均与其它方法的结果相吻合。由于本文方法推导简单,计算省时,所以是研究此类问题的有效途径。     

新型烟花药粉称重混合机的研制

目前,烟花药粉的称重混合工序主要以手工操作为主,是长期制约烟花爆竹安全生产的高危工序。针对这一工序,研发了一种专门用于烟花爆竹各配料称重、混合,并保证一定的称重精度及混合均匀度的混合称重机。基于粉体混合的定量计算及分析法,得出了混合度随时间变化的曲线,确定了粉体最佳的混合时间,并验算了药粉主要成分在混合前后的最大比例误差,结果完全满足烟花生产要求。     

Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.     

Nonhomogeneos Boundary-Value Problem for Semilinear Hyperbolic Equation. Stability

We discuss the solvability of the nonhomogeneous boundary-value problem for the semilinear equation of the vibrating string x _tt (t, y) − Δx(t, y) + f(t, y, x(t, y)) = 0 in a bounded domain and a certain type of superlinear nonlinearity. To this end, we deduce new dual variational method. Next, we discuss the stability of solutions with respect to the boundary control and initial conditions.      

A linearized model for estimating the performance of submerged resonant wave energy converters

A realistic performance analysis of oscillating water column wave energy converters (WECs) addresses to a set of non-linear differential equations that need to be integrated in time, by using a stochastic approach, under the hypothesis of random wind-generated sea waves, for all the sea states which characterize the location of the system. Non-linearities of the differential equations have several origins:

• minor and major losses of the unsteady flow of water and air;

• compressibility of air and heat exchange with the walls of the air chamber;

• non-linear characteristics of the turbine.

Under the hypothesis of random sea waves with Gaussian distribution, the authors propose an original methodology for linearizing the differential equations that describe the flow motion inside a wholly submerged WEC. Under such hypothesis, the linearized model can be used for predicting the power output by means of the calculations in the frequency domain and for control design. The developed methodology has been applied to the estimation of the performance of the new “resonant sea wave energy converters”, called REWEC, patented by Boccotti in 1998, and consisting of several caissons, characterized by a structure similar to the caissons of the traditional breakwaters and placed on the seabed, close one to each other, to form a submerged breakwater. Each caisson is connected to a vertical duct wholly beneath the sea level, where a hydraulic Wells turbine is placed.The matching between turbine and resonance characteristic of the system is carefully analysed in order to maximize the energy conversion efficiency.Some results, given for a small installation in the Mediterranean sea, confirm that the REWEC system is able to absorb a large share of the incident wave energy due to a very simple regulation system which permits the tuning on sea states with different significant heights.     

露天矿垂直与斜深孔爆破特征分析

根据永平铜矿实际爆破情况,运用爆轰理论,对露天矿垂直与倾斜两种中深孔的爆破特征进行了分析.分析从底盘抵抗线、孔网参数、大块与粮底、钻孔效率与作业成本和爆破地震效应五个方面入手,阐述了两种不同类型钻孔的不同爆破作用机制及其爆玻效果,肯定了倾斜孔在露天台阶爆破中所具有的独特优越性.