Studies on the Purity of 51Cr Labelled Human Serum Albumin

Different methods reported for the purification of Chromium-51 labelled human serum albumin have been studied in detail. It has been found that purification by ion exchange or dialysis does not remove some of the impurities such as complexed chromium and hydrated chromic oxide. Purification over DEAE cellulose or Sephadex (A-50) gives a product which is free from these impurities. It has been confirmed that chromium labelling leads to the formation of labelled protein aggregates and the specific activity of the labelled aggregates is greater than that of the non-aggregated fraction. These aggregates can be separated from the labelled monomer by column chromatography of Gel filtration.     

The use of high-throughput synthesis and purification in the preparation of a directed library of adrenergic agents

A library of potential agonists and antagonists for adrenergic receptors was prepared using high-throughput solution-phase parallel synthesis. Traditional solution-phase reductive amination reactions followed by rapid purification by ion exchange chromatography yielded products with near-analytical purity. An array of ketones and amines, arranged in an 8 × 12 matrix, were combined to form 96 individual compounds. This revised version was published online in August 2006 with corrections to the Cover Date.     

The Influence of Scattering Phenomena on the Performances of a 1/r axially symmetric Field Prism electromagnetic Separator

The elastic scattering in an electromagnetic separator with, 1/r axially symmetric magnetic field prism is treated by consideration of three sections on the ion path. Also some observations on the charge – exchange scattering in a device of this kind are given. Two numerical examples show that 1/r prisms compare favourably with the usual homogeneous and nonhomogeneous field separators also from the point of view of scattering phenomena.     

基于D-T紧凑型中子源的快中子照相准直屏蔽体设计及中子束特性模拟研究

中子照相是一种重要的无损检测技术,它能用于火工产品、毒品和核燃料元件等的检测。基于紧凑型D-T中子发生器,完成了一个用于快中子照相的准直屏蔽体系统（BSA）的物理设计。根据D-T中子源的能谱和角分布建立了中子源模型,采用MCNP4C蒙特卡罗程序,模拟了准直屏蔽体系统中中子和γ射线的输运,准直中子束相对于单位源中子的中子注量可以达到9.30×10-6 cm-2,准直中子束中主要是能量大于10 MeV的快中子;在设置的样品平面直径14 cm的照射视野范围,准直束中子注量的不均匀度为4.30%,准直束中中子注量与γ注量的比值为17.20,中子通量和中子注量比值J/Φ为0.992,说明准直中子束有好的平行性;准直屏蔽体外的泄露中子注量率与准直束中子注量率相比降低了2个量级。所设计的准直屏蔽体能满足快中子照相的要求。Neutron radiography is an important nondestructive testing technique. It can be used to detect the explosive devices, drug and the nuclear fuel element, etc. A beam-shaping-assembly (BSA) based on a compact D-T neutron generator is designed for fast neutron radiography in this paper. D-T neutron source model is constructed based on the neutron energy spectrum and angular distribution data. The transportation of neutron and γ-ray in the BSA is simulated using MCNP4C code. The neutron fluence of the collimated neutron beam with respect to the neutron source of the unit source is 9.30×10-6 cm-2. The collimated neutron beams is mainly fast neutrons with energies greater than 10 MeV. In the irradiation field range with a diameter of 14 cm, the neutron fluence uniformity of the collimated beam is 4.3%, the ratio of the neutron fluence to the gamma fluence in the collimated beam is 17.20, and the neutron flux and the neutron fluence ratio (J/Φ) is 0.992 which indicates that the collimated neutron beam has good parallelism. The leakage neutron fluence in outside of BSA is two orders of magnitude lower than that of the collimated neutron beam. The designed BSA can meet the need of fast neutron radiography.     

In vitro Studies on the Ability of Natural Zeolites to sorb some Radionuclides

The aim of our work was to study sorption and sorption kinetics of ⁸⁵Sr, ¹³⁷Cs and ¹³¹I from rumen liquid after application of zeolite (clinoptilolite) under laboratory conditions. Zeolite dump corresponded with usual (3%) and high (9%) dose of zeolite in feed. We have ascertained that zeolite is characterized with a high sorption ability for ⁸⁵Sr and ¹³⁷Cs from rumen liquid. 84% of ⁸⁵Sr and 98% of ¹³⁷Cs was bound after 24 hours.     

A Simple Method of the Flow Rate Determination of Fluids on the Basis of Diagrams obtained by a Radioactive Tracer Measurement

The simpliest and most convenient in a practical use method of the flow rate measurement, based on the tracer technique, is a such one, in which the passing time of the “tracer wave” is determined. The results are then obtained as a diagram of radiation intensity in the chosen points of the pipeline. The passing of the tracer over these points is marked on a recording tape in a form of the characteristic peaks. Depending on the kind of flow, the recorded peaks take the different shapes. In the first order they depend on the velocity profile in the pipe cross section. This differentiation of velocities causes that, when the distance between the detecting probe and the injecting unit increases, the tracer wave becomes more diluted, involving consequently a corresponding lengthening and flattening of peaks.     

"RLC串联电路暂态过程的研究"实验中电容系统误差的测量与修正

在"RLC串联电路暂态过程的研究"实验中,由于示波器两测量探头间电容和电容箱"零电容"的存在,导致阻尼振荡周期的理论计算值与实验值之间可能产生非常大的误差.本文通过测量上述两类电容,对周期的理论计算值进行了修正,使之与实验值的相对误差明显减小.