基于规范指标的一种模糊综合评判法

本文提出了一种基于规范指标的模糊综合评判法。这种方法以评判对象的种种规范指标为基本的评判标准。主要步骤是:(1)获取评判参数(即决定评判对象主要性能的各种参数),建立评判参数矩阵;(2)确定各参数的满意程度,建立满意度矩阵;(3)确定各参数的权重,建立权重集;(4)进行综合评判,得山评判结果。编制了通用程序,给出了具体算例。     

设计平底直动从动件凸轮机构的一种方法

从凸轮机构接触疲劳破坏这一主要失效形式出发,并考虑从动件预期运动规律对凸轮轮廓曲线最小曲率半径的基本要求,借助于极值和数值计算的理论,提出一种同时满足接触疲劳强度与实现预期运动双重约束条件的平底直动从动件凸轮机构基本尺寸——凸轮最小基圆半径的选择依据,从而扩展了此类凸轮机构的设计计算方法。     

S-饱和集的特征及其应用

引入并系统地研究了一般拓扑空间(X,τ)的非标准扩张(~*X,~*τ)的S-饱和集,证明了标准Souslin集与Loeb可测集的关系定理,得到了~*μ_L-零集在标准部分映射下是μ-零集的充分条件。     

心理健康的衡量标准探析

世界卫生组织认为,健康不仅是指肌体的强健和没有疾病,而且是指心理上的和谐完善,即个体的健康包括躯体健康和心理健康两方面。从某种意义上讲,心理健康更为重要。那么,怎样衡量个体的心理是否健康呢？笔者认为,对个体的心理是否健康可以从个体的学习、人际关系、自我意识、情绪状况、对生活和工作的态度等五个方面来进行衡量。     

Determination of arsenic,selenium and mercury in an estuarine sediment standard reference material using flow injection and atomic absorption spectrometry

A flow-injection analysis atomic absorption spectrometric (FIA-AAS) method was developed for the determination of trace amounts of arsenic, selenium and mercury in a proposed estuarine sediment standard reference material (SRM 1646a). The samples were prepared in two manners: a) A wet digestion procedure with HNO₃, H₂SO₄, and HClO₄ using a reflux column and b) A microwave-oven digestion procedure utilizing HNO₃, H₂SO₄, and HCl for As and Se, and HNO₃ for Hg. Microwave-oven digestion provides results comparable to those found by reflux column digestion and reduces the sample preparation time by a factor of 10. The proposed method employing the microwave-oven digestion procedure coupled with FIA-AAS for As and Se, and FIA-CVAAS for Hg, has detection limits of 0.15 ng As/ml, O.17 ng Se/ml and 0.15 ng Hg/ml.On leave from the Defense Metallurgical Research Laboratory, Hyderabad, India     

Application of an on-line preconcentration system in simultaneous ICP-AES

A PC-controlled on-line preconcentration system (TRACECON) developed by Knapp et al. [11], was connected to a JY-70 Plus simultaneous ICP spectrometer to preconcentrate on-line seven trace elements (Cu, Fe, Zn, Cr, Ni, Mn, V) in biological and environmental samples. EDTrA-cellulose was used as column material. The elemental concentrations were determined by simultaneous ICP-AES. The effect of pH of the sample solution on the enrichment was studied. It was found that the recoveries of chromium and iron depend strongly on the pH of the sample solution. All the elements mentioned were recovered quantitatively at pH 4.0±0.1. The flow rates of sample solution and element solution were optimized. The enrichment factors for seven elements at 5 ml loading volume range from 3.9 for Cu to 7.9 for Zn. The detection limits of all seven elements were improved. The accuracy of the method was tested by the analysis of a number of CRMs of NIST, BCR and NIES. Most results are in good agreement with the certified values.On leave from Shanghai Institute of Metallurgy, Academia Sinica, Shanghai 200050, People's Republic of China     

X-射线荧光光谱背景和基体效应综合校正公式

本文根据散射内标和公共背景法的有关理论,导出了两个X-射线荧光光谱分析校正方程,将背景、基体吸收和重叠干扰校正,以及校正曲线定量分析等多种运算合并进行,因而应用起来十分简便,两个方程在数学形式上与目前使用的X-射线光谱仪计算机程序中通用的数学模型相似,便于推广应用。     

镧与L-酪氨酸和甘氨酸三元固态配合物的热化学研究

由于稀土元素镧与氨基酸形成的配合物具有抗癌、抗肿瘤活性 ,人们对稀土氨基酸配合物的研究产生了浓厚兴趣。有关这类配合物的制备和表征的研究较多[1～ 4] ,而对其热化学性质的研究较少。我们按文献[5] 方法合成了配合物Ｌａ(Ｔｙｒ)(Ｇｌｙ) 3Ｃｌ3·3Ｈ2 Ｏ(ｓ) ,在自行研制的具有恒定温度环境反应热量计上 ,分别测定了Ｌａ2 Ｏ3(ｓ)、氨基酸 [Ｌ 酪氨酸 (Ｌｙｒ) +甘氨酸 (Ｇｌｙ) ]和配合物在2ｍｏｌ·Ｌ- 1 ＨＣｌ溶液中的溶解焓 ,通过设计的热化学循环得出配合反应焓 ,进而计算出Ｌａ(Ｔｙｒ)(Ｇｌｙ) 3Ｃｌ3·3Ｈ2 Ｏ(ｓ)的标准摩尔…     

紫外分光光度计标准溶液的制备及使用

介绍了紫外分光光度计标准溶液的特性及其用于检定紫外分光光度计准确度的优点和正确的使用方法。     

Micellization of dodecyldimethylethyl- ammonium bromide in aqueous solution

Specific conductivity of aqueous solutions of dodecyldimethylethylammonium bromide has been determined in the temperature range of 15-40°C. The critical micelle concentration (cmc) and ionization degree of the micelles, b, were determined from the data. Thermodynamic functions, such as standard Gibbs free energy, ΔG _m°, enthalpy, ΔG _m°, and entropy, ΔG _m°, of micellization, were estimated by assuming that the system conforms to the mass action model. The change in heat capacity upon micellization, ΔG _m°, was estimated from the temperature dependence of ΔG _m°. An enthalpy-entropy compensation phenomenom for the studied system has been found. This revised version was published online in July 2006 with corrections to the Cover Date.