A New Method for Calculating the Double Beta Decay Probability

A new method of calculating 2υ-2β decay probability ia derived. It is shown that with the present knowledge of nucleon-nucleon force and reasonable nuclear wave functions for the parent and daughter nuclei this method can provide a reliable result without using closure approximation.     

周期场聚焦电子束

引言 自从发现“强聚焦效应”可以应用在粒子加速器内以后,人们知道利用周期磁场能把离子束控制得更细,于是可以减少磁铁的需要量。因此近年来为了改建或新设计各种类型粒子加速器,对周期场聚焦离子束或电子束方面曾进行了很多研究工作。另一方面人们也开始研究用周期电场和磁场聚焦各种电子管内的电子束,例如行波管内电子束的聚焦等。聚焦电子束的主要特点在於必要考虑空间电荷。     

高频红外碳硫仪测定区域地球化学样品中的硫

高频红外碳硫仪由于便捷高效,常应用于区域地球化学样品中硫的分析检测。本文采用高频红外碳硫仪测定低中高含量的硫,以纯铁屑、锡粒和钨粒为助熔剂,对样品称样量、助熔剂的种类、加入顺序和用量等因素进行探讨,确定了最佳分析岩石、土壤和水系沉积物中硫含量的条件,并且用国家一级标准物质验证了该方法的准确度和精密度。结果表明,当样品和助熔剂的加入顺序和质量分别为：0.05 g样品、0.5 g铁助熔剂、1.7 g钨粒时,土壤和水系沉积物中硫的测定结果最稳定,岩石标准样品额外的加入0.5 g锡改善样品流动性,提高分析准确度。该方法的相对标准偏差（RSD）小于6%（n= 12）,相对误差绝对值小于8%。此方法具有操作简单、高效、稳定性好的特点,适合于大批量区域地球化学样品中硫的检测。     

铝单晶体滑移的电子显微镜颧察(二)

金屠的纯度和试样表面的处理等因素能影响品体滑移的形熊.     

核裂变材料核素成份的γ特征谱分析

研究对裂变核材料及有关核装置进行了无损探测与识别的物理可行性。其要点是由测量得到的γ特征能谱出发，通过对γ射线输运过程的物理分析并引入相应的参量描述，以推 论有关核材料的特征信息。数值计算模拟实验的结果表明，据此方法可以在有效的精度范围内由所测量到的裂变核材料的出射γ特征谱推算出其同位素成份等重要信息。研究结果还表明，考虑源区核材料的自吸收修正（称几何自屏蔽修正）是提高计算分析精度的关键因素之一。     

ADDENDUM

Abstract

Experiments have been performed to provide basic heat transfer data for thermal convection in a horizontal concentric annulus partially filled with water. A real-time holographic interferometry was employed to map the temperature distribution and a laser shadowgraph system was used to measure local heat transfer coefficients along the heated inner cylinder. Experimental results demonstrate that a minimum average Nusselt number for the water-wetted portion of the inner cylinder occurs at the air-water interface situated flush with the top of the inner cylinder. Corresponding numerical simulations were conducted for the cases of either fully or half-filled with water and the predictions agree well with the experimental results.     

Optimal Control of the Laplace Equation with Cauchy Data as Control Variables

In this not, we give necessary and sufficient conditions foroptimality of an ill-posed control system governed by the Laplaceequation with Cauchy data as control variables. A duality resultis also presented. This solves an open problem raised by J.L. Lions.     

A New Mechanism for Low Energy Pion Induced Double Charge Exchange Reaction

Using a method developed in theory of double beta decay[1], we propose a new mechanism, namely the two-nucleon pion absorption-emission mechanism for pion double charge exchange reaction at low energies. The calculations are compared with the experimental data of the angular distribution at 50 MeV and the 0° excitation functions of the DCX reactions on ¹⁴C, ¹⁸O with energies < 130 MeV. It is found that the contribution of this new mechanism is very important at low energies.     

QUARKONIUN POTENTIAL MODEL WITH A NON-ZERO GLUON EFFECTIVE MASS

According to Parisi's suggestion, we assume that the gluon possesses a non-zero effective mass μ. From the assumption we derive an effective Hamiltonian up to order β₂ for quarbnium. For μ=0.8GeV and 0.4 GeV, we find the spectra as well as the relative leptonic widths for charmonium upsilon, which are in good agreement with experiment.     

A POSSIBLE FIREBALL THEORY WITH SUPERSYMMETRY BETWEEN QUARK AND ANTIDIQUARK

A fireball theory in the quark level with supersymmetry between quark and antidiquark is suggested. A preliminary study of this model indicates that it can well describe all characteristic phenomena of multiproduction. In particular, the appearance of diquarks will enhance the baryon yield in multiproduction.