Permeability Effects of Turbulent Flow Through a Porous Insert in a Backward-Facing-Step Channel

In the present work, a k–v011035g54170869/xxlarge949.gif" alt="epsi" align="BASELINE" BORDER="0"> model, based on the work of Lee and Howell (Proceedings of the ASME-JSME Thermal Engineering Hawaii, 1987), is rigorously derived based on time average of spatially averaged Navier–Stokes equations. The model is then employed to solve for a flow in a backward-facing step channel with a porous insert. The numerical solver is modified from the STREAM code (Lien and Leschziner, Comput. Meth. Appl. Mech. Eng. 114 (1994a) 123–148), and it has been validated against the experimental data of Seegmiller and Driver (AIAA Journal 23 (1985) 163–171). The code is then used to perform simulation for cases with a porous insert. The resistance of the porous insert can be altered by changing its permeability (v011035g54170869/xxlarge954.gif" alt="kappa" align="BASELINE" BORDER="0">), Forchheimerv011035g54170869/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">s constant (F), or thickness (b). The goal is to examine the influence of each parameter on the resulting flow and turbulent kinetic energy (k) distributions. It is discovered that, by increasing the resistance of the insert, flow eventually enters a transitional regime towards relaminarization. This is due to the contribution of Darcyv011035g54170869/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">s and Forchheimerv011035g54170869/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">s terms in the governing equations, and modifying these two terms changes the levels of P_k and, hence, k and . Generally speaking, lowering v011035g54170869/xxlarge954.gif" alt="kappa" align="BASELINE" BORDER="0"> or raising F results in a greater suppression of P_k than v011035g54170869/xxlarge949.gif" alt="epsi" align="BASELINE" BORDER="0">, causing the flow to relaminarize. Meanwhile, if the pore size is reasonably large to sustain turbulence within the porous media, increasing b reduces but does not eliminate the turbulent activity in the porous insert.     

Design of a Beam with Controllable Force Elements

A method for solving the problem of design of an v4127/xxlarge8220.gif" alt="ldquo" align="MIDDLE" BORDER="0">intellectualv4127/xxlarge8221.gif" alt="rdquo" align="MIDDLE" BORDER="0"> structure formulated for the pair optimal position of actuators, optimal control of actuators is developed. In the method proposed, physical and logical objects are treated as v4127/xxlarge8220.gif" alt="ldquo" align="MIDDLE" BORDER="0">equivalent.v4127/xxlarge8221.gif" alt="rdquo" align="MIDDLE" BORDER="0">     

Optical and electrical properties of different oriented CVD diamond films

Due to different oriented diamond films having different properties, in this paper optical and electrical properties of different oriented diamond films have been investigated. The measured results indicate diamond films are of high quality and the properties of the (0 0 1)-oriented diamond film are better than those of the (1 1 1)-oriented one. Refractive index and extinction coefficient of (0 0 1)-oriented diamond film in the wavelength range of 2.5-12.5 μm is 2.391 and in the order of 10⁻⁵, respectively. And for the (1 1 1)-oriented one it is 2.375 and in the order of 10⁻⁴. The dark current of the (0 0 1)-oriented diamond film is 33.7 nA under an applied electric field of 100 kV/cm. The resistivity of the (0 0 1)-oriented diamond film obtained is about 2.33 × 10¹⁰ Ω cm. The current of (0 0 1)-oriented diamond film is almost no change with the time testing.     

Fixed points of approximable maps

We present a simple proof of the Leray-Schauder type theorem for approximable multimaps given recently by Ben-El-Mechaiekh and Idzik. We apply this theorem to obtain a Schaefer type theorem, the Birkhoff-Kellogg type theorems, a Penot type theorem for non-self-maps, and quasi-variational inequalities, all related to compact closed approximable maps.

     

Pr值逻辑函数相关免疫的等价判别条件

本文首先基于环Zpr中的元的padic分解并结合概率论的思想,给出了pr值随机变量的分解性质及pr值随机变量独立性的等价描述,然后在对pr值逻辑函数及其变元都进行padic分解的基础上,直接通过p值逻辑函数的Chrestenson谱给出了padic分解意义下pr值逻辑函数k阶相关免疫的线性组合引理和谱判别定理.     

ESR investigation of paramagnetic derivatives of [6-<Emphasis Type="Italic">tert</Emphasis>-butyl-4-(5-<Emphasis Type="Italic">tert</Emphasis>-butyl-2-methyl-3,4-dioxocyclohexa-1,5-dien-1-yl)-3-methylcatecholato]triphenylantimony(V)

A number of paramagnetic derivatives of [6-tert-butyl-4-(5-tert-butyl-2-methyl-3,4-dioxocyclohexa-1,5-dien-1-yl)-3-methylcatecholato]triphenylantimony(v) were investigated by ESR spectroscopy. The reactions of this complex with Cp₂Co or LiCl in the presence of Hg_metal. lead to the formation of free (nonchelated) radical anion semiquiones. Chelated complexes are formed in the case of Tl(Hg), Mn₂(CO)₁₀, Re₂(CO)₁₀, Sn₂Ph₆, Cu(met.), and CuCl + dppfc (dppfc is bis-diphenylphosphinoferrocene). Dedicated to Academician A. L. Buchachenko on the occasion of his 70th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2004–2009, September, 2005.     

飞秒激光-固体靶相互作用中渡越辐射的测量

 为了探索超热电子的加热机制，利用光学CCD相机和OMA光学多道分析仪，分别在靶背法线方向测量了光学渡越辐射（OTR）积分成像图案和光谱。实验在100 TW掺钛蓝宝石激光器上进行，飞秒激光与铜膜靶作用后，靶表面发光信号由空间分辨装置聚焦成像并引到CCD或OMA谱仪的狭缝上。测得的积分成像图案呈圆环状，光斑形成区域直径约为225 μm，在圆环边缘附近出现局部化明亮光信号，该现象表明，超热电子在传输的过程中存在成丝效应，其分布也不均匀。光谱在300～500 nm之间出现一系列非周期锐利尖峰，在400 nm（2ω0）附近出现的尖峰应归因于v×B加热机制产生的超热电子引起的相干渡越辐射（CTR）。     

Reaction of acrichin with hexachloroantimonic acid and its analytic application

The fluorometric reaction of acrichin (quinacrine hydrochloride) with hexachloroantimonic acid has been studied. The formation of a water-insoluble product has been shown. The precipitate contains equimolar quantities of acrichin and acid. The optimal conditions of formation, extraction, and determination were found. Acrichin was used for the extraction-fluorometry determination of nanogram amounts of antimony(v). Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 606–608, March, 1997.     

LiNbO_3晶体中Pr~(3+)离子的配位场能级计算

在C3v点群对称场中,运用双层点电荷配位场(DSCPCF)模型计算了LiNbO3晶体中Pr3+离子的40个配位场能级,与实验值相比,其均方根偏差为19.94 cm-1,优于文献值(44.22 cm-1).所得晶体场参数也明显好于文献值,说明双层点电荷模型能更好地拟合实验结果,对于研究C3v对称场中稀土离子的光谱特性具有非常重要的意义.