~(187)Pt的高自旋态能级结构

利用在束γ谱学技术和173Yb(18O,4n)熔合蒸发反应研究了187Pt的高自旋态能级结构.实验观测到基于νi13/2,ν7/2-[503],νi213/2νj,ν3/2-[512]和ν1/2-[521]组态的转动带,并且利用推转壳模型对这些转动带的性质进行了解释.总Routhian面计算表明:νi13/2转动带具有显著的负γ形变;负宇称带具有近似长椭球的形变.通过比较带内B(M1)/B(E2)比率的实验值和由Dnau和Frauendorf半经典公式得到的理论值,发现ν7/2-[503]转动带在低转动频率下的带交叉是由一对h9/2质子顺排引起的.

~(187)Pt的转动带性质研究

利用在束γ谱学技术和173Yb(18O,4n)熔合蒸发反应研究了187Pt的高自旋态能级结构．建立了包括3个转动带的187Pt高自旋态能级纲图．基于187Pt周围核结构的系统学和比较带内B(M1)／B(E2)比率的实验值和理论值,建议上述3个转动带的组态分别为11／2+[615],7／2-[503]和1／2-[521]．对各转动带的带交叉频率、顺排增益、旋称劈裂等进行了讨论．

High-spin structure in Pt-187

High-spin states in Pt-187 were studied via the Yb-173(O-18, 4n) reaction. Rotational bands based on the vi(13/2), v7/2(-)[503], vi(13/2)(2)vj, v3/2(-)[512] and v1/2(-)[521] configurations were observed, and interpreted within the framework of the cranked shell model. The TRS calculations show that the vi(13/2) band has an appreciable negative gamma deformation, and the negative-parity bands tend to have a near prolate shape with small positive gamma values. Experimental values of B(M1)/B(E2) ratios have been extracted and compared with theoretical values from the semi-classical Donau and Frauendof approach, strongly suggesting a low frequency pi h(9/2) alignment in the v7/2(-)[503] band.

Band properties of the transitional nucleus Pt-187

High-spin states in Pt-187 have been studied experimentally using the Yb-173(O-18, 4n) reaction at beam energies of 78 and 85 MeV. The previously known bands based on the nu i(13/2),nu 7/2(-)[503], and nu i(13/2)(2)nu j configurations have been extended to high-spin states, and new rotational bands associated with the nu 3/2(-)[512] and nu 1/2(-)[521] Nilsson orbits have been identified. The total Routhian surface calculations indicate that the transitional nucleus Pt-187 is very soft with respect to beta and gamma deformations. The band properties, such as level spacings, band crossing frequencies, alignment gains, and signature splittings, have been compared with the systematics observed in neighboring nuclei and have been interpreted within the framework of the cranked shell model. The rotational bands show different band crossing frequencies, which can be explained by the alignment either of i(13/2) neutrons or of h(9/2) protons. Importantly, evidence is presented for a pi h(9/2) alignment at very low frequency in the nu 7/2(-)[503] band. The proton nature of the band crossing is strongly suggested by comparing the measured B(M1;I -> I-1)/B(E2;I -> I-2) ratios with the theoretical values from the semiclassical Donau and Frauendof approach.

Quasiparticle nature of rotational bands in Pt-187

The high-spin states in Pt-187 have been studied experimentally by means of in-beam gamma-ray spectroscopy techniques via the Yb-173(O-18, 4n) fusion-evaporation reaction. The high-spin level scheme of Pt-187 has been established, including three rotational bands. Based on the systematics of level structure in neighboring nuclei and by comparing the experimental and theoretical B(M1)/B(E2) ratios, configurations of 11/2+ [615], 7/2(-)[5031 and 1/2(-)[521] have been proposed for the three rotational bands, respectively. Band properties of band crossing frequency, alignment gain and signature splitting have been discussed.

The effect of nucleation time on the growth of a microvoid in a viscoelastic material

In this paper, discussions are focused on the growth of a nucleated void in a viscoelastic material. The in situ tensile tests of specimens made of high-density polyethylene, filled with spherical glass beads (HDPE/GB) are carried out under SEM. The experimental result indicates that the microvoid nucleation is induced by the partially interfacial debonding of particles. By means of the Laplace transform and the Eshelby's equivalent inclusion method, a new analytical expression of the void strain at different nucleation times is derived. It can be seen that the strain of the nucleated void depends not only on the remote strain history, but also on the nucleation time. This expression is also illustrated by numerical examples, and is found to be of great usefulness in the study of damage evolution in viscoelastic materials.

大庆RP-3航空煤油热物性分析

针对广泛应用于超燃冲压发动机的吸热碳氢燃料,简要介绍了用于模拟燃料热物理特性的替代燃料方法和广义对应状态法则.以大庆RP-3航空煤油为例,选择了一个由49%（摩尔比）正十烷,44%1,3,5-三甲基环己烷以及7%正丙基苯组成的替代煤油用来模拟RP-3航空煤油进行热物理特性研究,并采用广义对应状态法则对替代煤油热力学和输运特性进行了数值研究.在此基础上,提出了预测超临界态流体通过音速喷管流量的新方法并得到了实验验证.

Electrothermal stress in conductive body with collinear cracks

The temperature and stress field in a thin plate with collinear cracks interrupting an electric current field are determined. This is accomplished by using a complex function method that allows a direct means of finding the distribution of the electric current, the temperature and stress field. Temperature dependency for the heat-transfer coefficient, coefficient of linear expansion and the elastic modulus are considered. As an example, temperature distribution is calculated for an alloy (No. GH2132) plate with two collinear cracks under high temperature. Relationships between the stress, temperature, electric density and crack length are obtained. Crack trajectories emanating from existing crack are predicted by application of the strain energy density criterion which can also be used for finding the load carrying capacity of the cracked plate. (C) 2003 Elsevier Ltd. All rights reserved.

Effects of physical parameter range on dimensionless variable sensitivity in water flooding reservoirs

The similarity criterion for water flooding reservoir flows is concerned with in the present paper. When finding out all the dimensionless variables governing this kind of flow, their physical meanings are subsequently elucidated. Then, a numerical approach of sensitivity analysis is adopted to quantify their corresponding dominance degree among the similarity parameters. In this way, we may finally identify major scaling law in different parameter range and demonstrate the respective effects of viscosity, permeability and injection rate.

CSM玻璃钢层间剪切断裂

本文对CSM-GRP层间剪切断裂用实验与分析方法进行了研究。用英国标准BS4994规定的双槽试件拉剪法测量了层间剪切强度(ILSS)。用有限元法计算了应力分布、损伤扩展和复合型应力强度因子。并讨论了BS4994规定的这一试验方法的可靠性。

热网管道热损失现场测试方法探讨

<正> 国外热网管道热损失测试多半采用热流计、红外测温仪、点温计等测试手段来实现。但现场测试时往往受到风、日照等非稳态影响。为探讨现场测试方法的可行性,采用了热流计法、表面温度法、温差法和焓降法来测量热网管道热损失。a.热流计法:用热流计直接测量管道保温层外表面热损失。b.表面温度法:测量管道保温层外表面温度、环境温度和风速,按对流换热和辐射换热公式来计算管道热损失。c.温差法:根据管道保温层内、外表面温度,内、外径以及实验室测得的保温材料导热系数,按径向一维导热计

假想分子与化学平衡

为了简化在求算有化学反应的气态物质的宏观热力学性质时所用到的概念和方法,本文引进“假想分子”的概念,导出了其化学势μ和绝对活度z=e~(μ/kT)的表达式。这样即可对化学平衡作出全新的物理解释,证明了化学平衡时,反应物的假想分子与生成物的假想分子可用统一的玻尔兹曼分布来表示,从而把有化学反应与无化学反应的体系统一了起来,并且简化了化学平衡时各能态上粒子数的计算方法。

Numerical study of bifurcation solutions of spherical Taylor-Couette flow

The steady bifurcation flows in a spherical gap (gap ratio sigma=0.18) with rotating inner and stationary outer spheres are simulated numerically for Re(c1)less than or equal to Re less than or equal to 1 500 by solving steady axisymmetric incompressible Navier-Stokes equations using a finite difference method. The simulation shows that there exist two steady stable flows with 1 or 2 vortices per hemisphere for 775 less than or equal to Re less than or equal to 1 220 and three steady stable flows with 0, 1, or 2 vortices for 1 220

Cauchy singular integral equation method for transient antiplane dynamic problems

In this paper, by use of the boundary integral equation method and the techniques of Green basic solution and singularity analysis, the dynamic problem of antiplane is investigated. The problem is reduced to solving a Cauchy singular integral equation in Laplace transform space. This equation is strictly proved to be equivalent to the dual integral equations obtained by Sih [Mechanics of Fracture, Vol. 4. Noordhoff, Leyden (1977)]. On this basis, the dynamic influence between two parallel cracks is also investigated. By use of the high precision numerical method for the singular integral equation and Laplace numerical inversion, the dynamic stress intensity factors of several typical problems are calculated in this paper. The related numerical results are compared to be consistent with those of Sih. It shows that the method of this paper is successful and can be used to solve more complicated problems. Copyright (C) 1996 Elsevier Science Ltd

Fusion energy-production from a deuterium-tritium plasma in the jet tokamak

Describes a series of experiments in the Joint European Torus (JET), culminating in the first tokamak discharges in deuterium-tritium fuelled mixture. The experiments were undertaken within limits imposed by restrictions on vessel activation and tritium usage. The objectives were: (i) to produce more than one megawatt of fusion power in a controlled way; (ii) to validate transport codes and provide a basis for accurately predicting the performance of deuterium-tritium plasmas from measurements made in deuterium plasmas; (iii) to determine tritium retention in the torus systems and to establish the effectiveness of discharge cleaning techniques for tritium removal; (iv) to demonstrate the technology related to tritium usage; and (v) to establish safe procedures for handling tritium in compliance with the regulatory requirements. A single-null X-point magnetic configuration, diverted onto the upper carbon target, with reversed toroidal magnetic field was chosen. Deuterium plasmas were heated by high power, long duration deuterium neutral beams from fourteen sources and fuelled also by up to two neutral beam sources injecting tritium. The results from three of these high performance hot ion H-mode discharges are described: a high performance pure deuterium discharge; a deuterium-tritium discharge with a 1% mixture of tritium fed to one neutral beam source; and a deuterium-tritium discharge with 100% tritium fed to two neutral beam sources. The TRANSP code was used to check the internal consistency of the measured data and to determine the origin of the measured neutron fluxes. In the best deuterium-tritium discharge, the tritium concentration was about 11% at the time of peak performance, when the total neutron emission rate was 6.0 × 10¹⁷ neutrons/s. The integrated total neutron yield over the high power phase, which lasted about 2 s, was 7.2 × 10¹⁷ neutrons, with an accuracy of ±7%. The actual fusion amplification factor, Q_DT was about 0.15