福建省带壳牡蛎中副溶血性弧菌的市场调查

为了解零售带壳牡蛎中副溶血性弧菌(VP)的污染情况，2003年4月～2004年3月每月在福建省福州和厦门两地收集带壳牡蛎，样品共252份，分别来自水产品批发市场(11％)、零售市场(50％)和饭店(39％)。采用Vitek鉴定系统和最可能数(MPN)法进行VP的定性和定量分析。结果显示，带壳牡蛎VP几何平均密度为46MPN，100g，46％的试样VP密度低于30MPN/100g的最低检出限，仅厦门2个试样菌量超过104MPIN/100g。两个地区、不同采样点和不同季节之间试样vP平均密度差别均有显性。厦门试样菌量高于福州；批发市场试样菌量最高；春季试样菌量(93MPN/100g)高于其它季节(约为40MPN/100g)。研究结果可以用于估计生食牡蛎人群VP的暴露量。     

Quantitative trait loci for meat quality traits in pigs considering imprinting and epistatic effects

The aim of the research was to gain a better understanding of the genomic regulation of meat quality by investigating individual and epistatic QTL in a three-generation full-sib population (Pietrain x crossbred dam line). In total, 386 animals were genotyped for 96 markers. Analysed traits included pH, reflectance value, conductivity, and meat colour. Thirteen significant individual QTL were identified. The most significant QTL were detected on SSC1 and SSC9 for pH, on SSC4 for meat colour, and on SSC8 for conductivity, accounting for 3.4% to 4.7% of the phenotypic variance. Nine significant epistatic QTL pairs were detected accounting for between 5.7% and 10.9% of the phenotypic variance. Epistatic QTL pairs showing the largest effects were for reflectance value between two locations of SSC4, and for pH between SSC10 and SSC13, explaining 9.5% and 10.9% of the phenotypic variance, respectively. This study indicates that meat quality traits are influenced by numerous QTL as well as a complex network of interactions.     

无机氢酸强度的定量计算

提出了定量计算无机氢酸H_mX强度的两个公式,尝试从无机氢酸H_mX的分子结构及非金属原子X的结构参数(X~(m-)的离子半径r及其电荷Z,或X的原子实半径r~*及其有效核电荷Z~*)定量预测无机氢酸的强度。计算值与文献值的平均误差分别为0.82和0.40。     

Statistical simulation and the distribution of distances between identical elements in a random sequence

We study the distributions of distances between identical elements of a random sequence (e.g. a sequence of coin tosses or die tosses). We provide methods to generate observations by means of a statistical simulation and show in particular that distributions of multiple distances obey a linear or geometric (mixture) probability model, respectively. The results are useful to discover certain structures in texts or other information strings.     

复合激光诱导荧光定量标定技术及其对喷雾特性研究的应用Ⅰ:燃油喷雾当量比定量标定方法

应用复合激光诱导荧光技术建立了定容燃烧弹中荧光强度和喷雾浓度间关系的定量标定方法,获得柴油喷雾气相、液相浓度量化数值,并针对影响定量标定的各种环境因素开展了深入的量化研究。试验中分析了荧光强度和气相喷雾浓度间的系数(Kvapor)随环境条件改变时的变化情况并发现:系数Kvapor随环境压力升高而降低;环境气体成分的变化对系数Kvapor并没有明显影响;环境温度升高使得系数Kvapor呈现先上升后下降的趋势,600K左右是拐点位置,600K以前随温度升高而升高,600K以后随温度升高而快速下降。最终,根据试验结果建立了系数Kvapor随环境温度和环境压力变化的三维Map图,并应用其获得喷雾气相当量比浓度数值和液相浓度数值的定量结果。     

A Low-Shear Titration Viscometer Suitable for Investigation of DNA and Other Polymers

SUMMARY

The viscosity of linear high-molecular-weight substances should be measured at sufficiently low shear gradients, e.g., with the aid of the ingenious Zimm-Crothers rotating-cylinder viscometer [1]. To investigate properties of nucleic acids or other polymers and their interaction with substances such as certain ions, dyes, etc., it proves useful to follow changes in polymer viscosity with increasing concentrations of the added interacting substance.     

Hydroxylamine production: will a QRA help you decide?

The recent publication by the US Chemical Safety Board (CSB) concerning its findings on the Concept Sciences Inc. (CSI) incident involving hydroxylamine (HA) has raised issues with regard to safe production of HA. This CSI incident was followed by another incident that destroyed the Nissin Chemical HA plant in Japan, and today BASF is the sole commercial producer of HA. HA is an important solvent in the pharmaceutical industry and is used as an etching agent in the semi-conductor industry.This paper discusses a Quantitative Risk Assessment of a generic HA production plant, which integrates the findings of the CSB report and the knowledge of potential HA reactivity hazards based on research at the Mary Kay O'Connor Process Safety Center. The intent is to highlight safety concerns and major risk factors in the production and handling of HA and to provide risk assessment guidelines for potential manufacturers. These guidelines are also applicable to the production strategies for other hazardous chemicals.     

定量荧光录井识别真假油气显示方法探讨

针对定量荧光录井中存在的有机物荧光干扰问题,文章通过室内消除干扰的模拟实验,提出了消除干扰的两种方法,一种是直接采用荧光谱图的差异区分混入的有机物与地层含油荧光的干扰,另一种是利用荧光差谱及相当油含量的变化落实显示。经过实例应用得到了较好的效果。有利于定量荧光录井技术在现场的油气解释和评价。     

断块油田防砂效果研究方法

我国的第三系出砂油层在构造特征上大多呈现多断、多阶、垒、暂相间的面貌，且由于陆相沉积地层非均匀性严重，使防砂工艺必须结合断块油田的具体地质情况才能发挥良好的效果。文中结合断块油田的实际，分析了影响防砂效果的因素和判断依据，提出利用物理建模－数据采集－数据处理的研究方法在断块油田进行防砂效果研究，对防砂效果由定性评价转换为定量评价。