Instability Parameters of Optical Oscillation Frequency in Plasma Central Discharge and Periphery Region

We have observed relaxation oscillations in a capacitive discharge in Ar gas, connected to a peripheral ground chamber. The plasma oscillations observed from time-varying optical emission from the main discharge chamber show, for example, a high frequency （75.37kHz） relaxation oscillation, at lOOmTorr and 8 W absorbed power, and a low frequency （2.72Hz） relaxation oscillation, lOO mTorr and 325 W absorbed power. Time-varying optical emission intensity and plasma density are also detected with a Langmuir probe. The theoretical result agrees well with experiments.     

暗物质寻找实验中CsI（T1）晶体反符合探测器实验研究

一个正在建设的位于韩国Y2L地下实验室的低能暗物质探测实验中,采用了CsI（T1）晶体反符合探测器作为主动屏蔽体.本工作对CsI（T1）晶体反符合探测器的实验性能进行了研究.通过FADC系统记录的脉冲波形数据,研究了探测器的能量分辨率和波形甄别的能力;研究相同能量γ射线入射到反符合探测器不同位置的相对光输出将有助于选择探测器的工作参数;为了解晶体自身放射性对暗物质测量的影响,利用低本底HPGe探测器对CsI（T1）晶体内部的放射性进行了测量,得到晶体内部Cs同位素的放射性活度.探测器系统进行了约18d的试运行取数.实验数据表明,CsI（T1）晶体探测器的反符合效率约为31%,HPGe探测器的本底计数率水平约为133cpd.为了进行暗物质探测研究,需要采取有效的方法进一步降低探测器的本底水平.     

YP1xVxO4∶Eu3+在真空紫外区发光的优化

系统地考查了Eu3 + 在YPO4 YVO4 固溶体中的发光。当V5+ 的浓度低于 0 3 ,出现VO4 3 -离子团的蓝色发射 ;直到V5+ 的浓度等于或大于 0 3时 ,VO4 3 -离子团的蓝色发射才被Eu3 + 离子的红色发射所猝灭 ,发射主波长在 61 9nm。在真空紫外线的激发下 ,Eu3 + 在YPO4 YVO4 固溶体有较强发光 ,并随着P5+ 浓度的增加 ,Eu3 + 离子的发光增强。经过优化的组成为YP0 7V0 3 O4 ∶Eu3 + 的荧光粉在真空紫外激发下既具有较强的发光 ,又具有优良的色纯度 ,将是一种新型的良好的等离子体平板显示用荧光粉。     

STUDY OF THE IMPINGEMENT OF IMPULSE WAVE UPON A FLAT PLATE

The impulse wave is made by the weak normal shock discharge from an open end of a shock tube. In order to understand the dynamic characteristics of the impulse wave impinging upon a flat plate, experiments are performed over the shock Mach number range from 1·01 to 1·20. A flat plate is placed downstream, normal to the axis of the shock tube, to simulate the impulse wave impingement on an object. The distance between the exit of the shock tube and flat plate is changed. The baffle plate is installed at the exit of the shock tube. The sizes of the baffle plate and impinging flat plate are varied to investigate the magnitude of the impulse wave impinging upon the flat plate. Computational analysis is applied to model the flow field subject to unsteady, axisymmetric, inviscid, compressible, equations. Computational results well predict the experimented dynamic behavior of the impinging impulse wave. The impulse wave impinging upon the flat plate has a sharp peak of very short rising time and its magnitude decreases with distance from the center of the flat plate. The magnitude of the impulse wave impinging upon the flat plate can be predicted by the empirical equations that are developed in the present study.     

DESIGN SENSITIVITY ANALYSIS AND OPTIMIZATION OF AN ENGINE MOUNT SYSTEM USING AN FRF-BASED SUBSTRUCTURING METHOD

The FRF-based substructuring method is one of the most powerful methods in analyzing the responses of complex built-up structures with high modal density. In this paper, a general procedure for the design sensitivity analysis of a vibro-acoustic system has been presented using the FRF-based substructuring formulation. For an acoustic response function, the proposed method gives a parametric design sensitivity expression in terms of the partial derivatives of the connection element properties and the transfer functions of the substructures. The derived noise sensitivity formula is combined with a non-linear programming module to obtain the optimal design for the engine mount system of a passenger car. The objective function is defined as the area of the interior noise graph integrated over a concerned r.p.m. range. The interior noise variations with respect to the dynamic characteristics of the engine mounts and bushings have been calculated using the proposed sensitivity formulation and transferred to a non-linear optimization software. To obtain the FRFs, a finite element analysis was used for the engine mount structures and experimental techniques were used for the trimmed body including the cabin cavity. The optimization based on the sensitivity analysis gives the ideal stiffness of the engine mount and bushings. The resultant interior noise in the passenger car shows that the proposed method is efficient and accurate.     

浦项中子装置上209Bi中子全截面测量(英文)

在浦项中子装置(PNF) 的100 MeV电子直线加速器上利用透射法和飞行时间法测量了209Bi 的0.1~100 eV的中子全截面。文中对于实验装置特点、用吸收片法拟合本底、拟合中子飞行距离和时间零点的处理过程做了较为详细的描述。测量结果与以前发表的实验数据以及评价数据ENDF/B-VII.1 做了比较,比较结果符合得较好。     

Atomic Diffusion in Cu/Si （111） and Cu/SiO2/Si （111） Systems by Neutral Cluster Beam Deposition

The Cu films are deposited on two kinds of p-type Si （111） substrates by ionized duster beam （ICB） technique. The interface reaction and atomic diffusion of Cu/Si （111） and Cu/SiO2/Si （111） systems are studied at different annealing temperatures by x-ray diffraction （XRD） and Rutherford backscattering spectrometry （RBS）. Some significant results are obtained： For the Cu/Si （111） samples prepared by neutral dusters, the interdiffusion of Cu and Si atoms occurs when annealed at 230℃. The diffusion coefficients of the samples annealed at 230℃ and 500℃ are 8.5 ×10^-15 cm^2.s^-1 and 3.0 ×10^-14 cm^2.s^-1, respectively. The formation of the copper-silicide phase is observed by XRD, and its intensity becomes stronger with the increase of annealing temperature. For the Cu/SiO2//Si （111） samples prepared by neutral dusters, the interdiffusion of Cu and Si atoms occurs and copper silicides are formed when annealed at 450℃. The diffusion coefficients of Cu in Si are calculated to be 6.0 ×10^-16 cm^2.s^-1 at 450℃, due to the fact that the existence of the SiO2 layer suppresses the interdiffusion of Cu and Si.     

表面含磺酸基的介孔分子筛催化剂SBA-15-SO3H的制备及其催化性能

采用直接和后合成两种方法制备出含磺酸基的介孔分子筛SBA-15-SO₃H,用XRD和红外光谱分析制备过程中催化剂结构和组成的变化.结果表明,两种方法制备出的含磺酸基的催化剂都保持了SBA-15分子筛的完整晶体结构,并含有质子酸中心-SO₃H;固体核磁共振表征结果证明,两种方法都使MPTMS存在于分子筛的表面;用N₂吸附-脱附测定了它们的比表面积、孔径和孔容;TGA分析认为,MPTMS在分子筛表面的热稳定性大于300℃,酸碱滴定结果说明,直接法获得的催化剂的酸中心多于后合成法.酯化反应结果表明,直接法合成的催化剂比后合成法具有更高的稳定性,且简便、快捷、高效.     

Purification and Characterization of Cyclic AMP-Binding Protein from Ganoderma lucidum

Cyclic AMP-binding protein was purified 30 fold from the mycelia of Ganoderma lucidum by the methods of ammonium sulfate precipitation, DEAE-cellulose, phospho-cellulose ion exchange chromatography and Sephacryl S-100 gel filtration. The molecular mass of the purified protein is 34.5 kDa and 17 kDa by Sephacryl S-100 gel filtration and SDS-ployacrylamide gel electrophoresis, respectively. From these results it is suggested that the protein has a homometric dimmer structure. The pI of the purified protein is pH 8.2 by native isoelectric focusing gel. The half-life of the protein activity in 10% glycerol at 4 ℃ is 7 d in crude extract, but its half-life is only 3 d under purifying conditions. The optimal conditions of the protein activity are at 1 ℃ and pH 7.5. Its activity is increased 6 times by 1 mmol/L Zn^2 and is slightly inhibited by cGMP,Cu^2 and Mn^2 .