滤膜法检验水中总大肠菌群方法中一些问题的探讨

建立滤膜法在检测总大肠菌群的关键步骤。要使大肠杆菌的检验结果比较能正确反映被检水中的大肠杆菌群得数量,应选取适量水量,并应作两份平行检验     

浅议滤膜法检验水中总大肠菌群方法有关问题

水质细菌学检测是水质分析中的重要指标,其对于保障居民饮用水安全具有关键指导意义。本文作者基于多年水质检验的实践工作经验,从理论依据、操作步骤及注意事项等方面对滤膜法检验水中总大肠菌群方法有关问题进行探讨,以期在实践工作中具有借鉴作用。     

水环境中两种大肠菌群标准检测方法的对比研究

大肠杆菌是人及各种动物肠道中的正常寄居菌,食物或水中大肠杆菌的检出即意味着直接或间接的近期粪便污染。在检测原理和步骤、适用范围以及检测结果等方面对两种常规的大肠菌群检测方法作了对比研究。     

饮用水中大肠杆菌标准检验方法及仪器化进展

大肠杆菌是饮用水重要的微生物指标细菌,目前的标准检验方法有多管发酵法、膜过滤法、酶底物法。由于饮用水的测试量迅速上升,以及对现场快速检验方法的需求,为降低分析人员劳动强度,减少人为误差,提高分析效率,市场开始研制和生产基于酶底物法的大肠杆菌检测仪器。     

松北湿地水质中粪大肠菌群的测定

湿地被为"自然之肾",具有独立特殊功能的生态系统。它是自然界最富生物多样性的生态景观和人类最重要的生存环境之一,不但具有丰富的资源,还具有巨大的环境调节功能和环境效益。粪大肠菌群是判定水体水质要指标之一,水中的病原菌多数来源于病人和病畜的粪便。本文介绍了利用多管发酵法检测哈尔滨松北湿地内的粪大肠菌群数的实验。     

粪大肠菌群的测定——多管发酵法

对地表水和废水中粪大肠菌群目前通用的多管发酵检测方法进行优化。本文结合作者多年的工作实践对粪大肠菌群的测定方法（多管发酵法）进行分析探讨。     

沙门氏菌检测方法的探讨

本文提出了一种检验沙门氏菌的方法-酶底物法．应用β-萘酚辛酯酶为底物,经沙门氏菌酶解,释放出β-萘酚,与固兰作用出现的紫色,能够在短时间内得到检验结果,反应在纸片上进行。通过一定的实验,确定了酶底物法适用于基层小实验室使用。经过与三种现有的沙门氏菌检验方法比较,证明该方法是快速且有效的。     

检测耐热大肠菌群培养基的质量控制方法探讨

培养基的质量是微生物检测工作的基础,直接影响检测结果的可靠性。本文结合实际情况,从外观、pH值、无菌检查及灵敏度检查等几个方面,对检测耐热大肠菌群所用EC培养基的质量控制进行讨论,以便微生物实验室不断完善和提高培养基的质控水平,从而保证检验结果的准确性。     

三种检测微囊藻毒素的ELISA方法比较研究

建立了抗原抗体复合物酶联免疫法(anti-immune complex ELISA,ICELISA)、间接竞争酶联免疫法(Indirect cELISA)、直接竞争酶联免疫法(Direct cELISA)三种检测微囊藻毒素的酶联免疫方法,确定了每种方法的检测限、线性范围以及重现性。以三种方法分别对标准品、藻样、水样及水产品中微囊藻毒素进行了测定,并对三种分析方法进行了较为系统的比较研究,为微囊藻毒素ELISA试剂盒的研制奠定了基础。     

酶底物法和国标法测定饮用水中菌落总数的比较

本文使用酶底物法和国标法对地下水、水源水、饮用水中菌落总数进行了监测,结果经统计学检验,两种方法监测结果的P值小于0.5,无显著性差异。酶底物法可以替代国标法用于评价饮用水中微生物。     

A study on open shop scheduling to minimise total tardiness

This paper deals with open shop scheduling to minimise total tardiness. Contrary to other scheduling problems (i.e., flow and job shops), the formulation of the open shop is given far less attention in the literature. Therefore, we intend to fulfil this gap by the presentation of four different mixed integer linear programming models. We compare the models on the basis of their complexity sizes. Furthermore, we propose two metaheuristics based on genetic algorithm and variable neighbourhood search. We exhaustively explore the effect of different operators and parameters on the performance of genetic algorithm by means of Taguchi method. Two computational experiments are conducted to evaluate the models and algorithms for performance. The first one includes small-sized instances by which the models and general performance of the algorithms are examined. The second one consists of three well-known benchmarks by which we further evaluate the algorithms. The results show the effectiveness of the proposed models and algorithms.     

3种不同前处理方法测定卤粉中铅含量的比较研究

比较3种不同前处理方法对卤粉中铅含量测定结果的影响。分别采用微波消解、湿法消解、干法灰化对样品进行前处理,采用石墨炉原子吸收法测定。微波消解耗时短,酸用量小,回收率较好。湿法消解耗时长,酸用量比较多,回收率较高。干法灰化耗时较长,酸用量小,由于灰化温度较高,元素有一定损失,回收率偏低。3种前处理方法均适用于卤粉中铅含量的测定。其中微波消解耗时短,酸用量小,回收率较好,是一种比较好的方法。     

连续流动法测定烟草水溶性糖的影响因素

为提高RFA-300连续流动分析仪测定烟草及烟草制品中水溶性糖含量的准确性.依据行业标准YC/ T159—2002对各种影响因素进行了考察,发现标准样品的种类、纯度及反应时间是主要影响因素,并根据试验结果和测试原理的要求对仪器管路进行了适当的加长。确定了以葡萄糖为标样.采用校正标样和加长仪器管路的连续流动法测定烟草制品中的水溶性糖。结果表明,改进后方法的回收率为98.8%-107.9%,变异系数为1.63%. 测定结果与芒森·沃克法的基本一致。     

三个国标中甲醛测定方法的比较和探讨

对GB 18582-2001、GB 18583-2001、GB/T 15516-1995三个国家标准中甲醛含量测定方法进行了比较,指出了其异同点,并提出了笔者对标准的一些理解和看法。     

全热交换器交换效率影响因素的试验研究

试验研究全热交换器的交换效率的影响因素。试验表明,全热交换器的风量、风压的变化对全热交换器的交换效率有较大的影响。     

A comparative numerical study of combined cold expansion and local torsion on fastener holes

Cold expansion and local torsion processes provide controllable strengthening mechanisms for a fastener hole and therefore have engineering significance. They rely on the residual stress and the accumulated shearing strain, respectively, which are difficult to measure. Due to the complex closed form solutions for these mechanisms, their numerical study is of great importance. In this work, a combination of the cold expansion and the local torsion on a fastener hole has been investigated numerically to evaluate the amount and nature of the total accumulated residual stresses around a fastener hole. Different cases of the cold expansion and the local torsion processes were modelled and studied by finite element simulation to investigate the existence of a loading case which produces a beneficial compressive residual stress field in the vicinity of a hole. Sensitivity of the final residual stress with respect to a range of process parameters including adequate diametral interference and angle of rotation was investigated.     

A study of the dissipative properties of homogeneous materials deposited as coatings. Part 1. Method for the determination of the amplitude dependence of the true vibration decrement of the coating material

A method is proposed for the determination of the amplitude dependence of the true vibration decrement of homogeneous materials deposited as coatings on a substrate of rectangular cross section. The method is based on the self-consistent calculation of energy loss factors for the substrate and coating materials using experimental amplitude dependences of vibration decrement for coated substrate, obtained under the conditions of cantilever specimens of rectangular cross section. The applicability of the method is illustrated by the determination of values of the true vibration decrement of Co-20 wt.% Fe alloy deposited as a coating on VT1-0 titanium alloy. __________ Translated from Problemy Prochnosti, No. 6, pp. 134–143, November–December, 2007.     

几种照相加工用化学品的制法探讨

本文报导了苯骈三氮唑及其衍生物、苯骈噻唑鎓盐、4—甲基—1—苯基—3—吡唑烷酮、过—硫酸复盐、EDTA铁铵盐以及硫代硫酸铵等数种照相冲洗用化学品的制备方法,并对其中某些方法作了简单的比较。     

渗透汽化丁酮甲苯混合溶剂脱水研究

用自制的PVA／PAN复合膜进行了渗透汽化丁酮甲苯混合溶剂脱水试验,并与模型预测脱水极限值进行了比较,取得了一些有意义的结果。     

大型空分设备循环冷却水处理方法的对比研究

武钢氧气公司在大型空分设备循环冷却水系统中,采用化学法和物理法进行水处理效果的实践探索,从原理和监测数据上进行了对比、分析研究,确认物理法具有高效除垢、防垢、杀菌灭藻、缓蚀以及净化等功能,可以取代化学法进行循环水处理。