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为了保障以粘弹性颗粒驱油剂(PPG)、聚合物、表面活性剂组成的非均相复合驱的方案设计和矿场实施的顺利进行,针对现有的聚合物质量浓度测定方法无法直接、准确测定PPG质量浓度的问题,在室内分别采用超声波和离心萃取对单一PPG溶液及含原油PPG溶液进行预处理,并根据PPG中含氮元素的特性,采用化学发光定氮法对经过预处理的PPG溶液的质量浓度进行了测定,从而建立了PPG质量浓度测定新方法。实验结果表明,在超声波功率为500 W,超声时间为15 min,离心机转速为10 000 r/min,离心时间为3 min,萃取剂为甲苯的条件下,新建立的测定方法能够有效测试PPG质量浓度。测定结果与样品质量浓度的相对误差小于4.0%,最低检测界限为10 mg/L,能够满足矿场监测的需求。 相似文献
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《Food Control》2006,17(11):890-893
In the pectin analysis of foods by visible spectrophotometry using the m-hydroxydiphenyl (MHDP) as the chromogenic reagent, the evolution of the absorbance at 520 nm of the MHDP/5FF chromophore with respect to the elapsed time from the beginning of the reaction for different d-galacturonic acid concentrations was studied.It was observed that after 45 min, the stability of the readings predicted by the different methods was not reached. This evolution depended on the d-galacturonic acid concentration. The need to analyse the samples in sequence was noted, in such a way that after the addition of MHDP, a protocol was established so that the spectrophotometric data measurements taken at the highest absorbance have high reproducibility. 相似文献
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几种水解聚丙烯酰胺及其相似物浓度测定方法分析 总被引:4,自引:0,他引:4
通过检索1975~2002年期间有关HPAM及其相似物浓度测定的研究成果,论述了6种水解聚丙烯酰胺及其相似物浓度测定技术,但其中5种测定技术受水解聚丙烯酰胺及其相似物水解度的影响,要求制作标准曲线的HPAM水解度和待测样品中HPAM的水解度相同.通过对6种测定技术的基本原理、特点、干扰因素和应用范围评价得知,SEC和荧光分光光度法检测灵敏度最高,适用于样品中微量HPAM浓度测定;淀粉-碘化镉比色法干扰因素较少,精确度较高,是较为实用的方法,用于油田室内动态、静态吸附滞留研究和现场采出液聚合物浓度测定;粘度法可用于高浓度HPAM注入液常规质量检测,快速简便;浊度法具有较高的准确度和较少的干扰因素,在油田也有较广泛应用. 相似文献
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张汉沛 《石油与天然气化工》2014,43(5):558-563
综述了我国车用汽油中硫含量的控制指标和测定方法。我国车用汽油标准从1999年开始历经了国Ⅰ标准、国Ⅱ标准、国Ⅲ标准、国Ⅳ标准和国Ⅴ标准5个阶段,目前已全面实施国Ⅳ标准,2018年起将全面实施国Ⅴ标准,硫含量控制指标从2000年以前的不大于1 500mg/kg降低到目前的不大于50mg/kg,2018年起将全面实施不大于10mg/kg的控制指标。对燃灯法、紫外荧光法、氧化微库仑法、能量色散X射线荧光法、波长色散X射线荧光法等硫含量测定的常用方法的特点、测定限值、重复性、采用情况等作了论述,提出今后研究的方向为气相色谱-选择性检测器联用法,并对其进行了论述。 相似文献
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V. N. Zrelov N. G. Postnikova L. V. Krasnaya 《Chemistry and Technology of Fuels and Oils》1994,30(4):183-187
Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 4, pp. 28–30, April, 1994. 相似文献
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《Food Control》2016
Handwashing is relied upon in numerous fields as a primary means to prevent transmission of harmful pathogens. While handwashing is a key step in disease prevention, the factors controlling its effectiveness are not always well understood, and there are extensive variations in the methodology used to assess each of these factors. This review summarizes the various factors that can impact handwashing effectiveness as well as the methods and results of studies evaluating each of these factors related to handwashing. Numerous methods are available to inoculate hands as well as to recover microorganisms from hands, and for a given method, experimental variables can be changed between researchers. These variations amongst methods as well as variations in reporting experimental results can make it difficult to compare studies as well as challenging to accurately interpret the results between studies. Standardization of methods and reporting requirements are necessary to allow for comparison of studies so that more accurate conclusions about the handwashing process can be made. Therefore, the need for 1) the development of more standardized handwashing test methods and 2) the formation of guidelines on the minimal information required for publication of handwashing experiments are considered and discussed. 相似文献
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工业上测定气体中总硫含量的方法甚多,但在油气加工工业中应用较多的是氧化微库仑法和紫外荧光法.由于氧化微库仑法是可以直接溯源至SI制的基准方法,其测量不确定度明显优于属于标准方法的紫外荧光法,故建议采用氧化微库仑法作为仲裁方法.相对于氧化微库仑法,紫外荧光法的操作较简便,分析速度较快,且不使用有毒的电解液,具有环保优势,... 相似文献
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《Food Control》2015
Acrylamide (AA), a neurotoxin and potential carcinogen, has been found in various thermally processed foods such as potato chips, biscuits, and coffee. LC–MS/MS and GC–MS as standard detection methods show high sensitivity, selectivity, stability, and repeatability. However, these methods require expensive instruments, skilled technicians in laboratories, and high testing costs, and cannot meet the needs for real-time and on-line detection of AA in foods. Therefore, rapid detection methods with merits of simplicity and portability such as computer vision, ELISA, electrochemical biosensing, and fluorescent biosensing have obtained an increasing amount of attention. Reported research on rapid methods has shown similar sensitivity and selectivity, but requires less time and cost in comparison with standard methods through the use of nanomaterials and biomolecules with high affinity to AA. These improvements show great promise for high-throughput, real-time, and on-line detection of AA. This paper provides a comprehensive overview of rapid detection methods for AA in foods with comparison between rapid and standard methods. Meanwhile, suggestions for further research on rapid methods for detecting AA are also discussed based on technical challenges and industry needs. 相似文献
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对大庆炼化公司腈纶厂聚合牛产装置建设投产及工艺情况进行了介绍,针对长丝及短纤颜色发黄原因进行了细致的研究,其中聚合反应第二单体VA中乙酸甲酯和乙酸乙酯含量高低与纤维颜色有关系,通过国内外VA产品中乙酸甲酯和乙酸乙酯含量进行对比找到了纤维发黄的机理,在形成高聚物的后续生产工序中提出了解决办法。 相似文献
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Current methods for the prediction of the safe shelf life of gun and mortar propellants are evaluated. This is achieved in a four part approach. Firstly, the current picture of the chemical stability of gun propellants is presented. Secondly, the concepts of stability testing and artificial ageing are reviewed. Thirdly, the traditional and fourthly, the modern testing methods are discussed. In this way, it is possible to identify the reasons for replacing traditional with modern methods and to indicate the methods which would be most appropriate to implement in a country's stability surveillance program for its stored propellants. 相似文献
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反Q滤波方法研究综述 总被引:1,自引:0,他引:1
地震波在地下介质中传播会产生吸收衰减现象,从而降低地震资料的信噪比和分辨率。补偿这种吸收衰减最常用的方法是反Q滤波,因此,国内外专家、学者对反Q滤波方法进行了大量研究。反Q滤波方法可以分成用级数展开作近似高频补偿的反Q滤波方法、基于波场延拓的反Q滤波方法和其他反Q滤波方法三大类,对各种反Q滤波方法进行了综述,分析了方法的效率和稳定性,指出了目前反Q滤波方法还存在的一些尚待解决的问题。 相似文献
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反Q滤波方法研究综述 总被引:2,自引:1,他引:1
地震波在地下介质中传播会产生吸收衰减现象,从而降低地震资料的信噪比和分辨率。补偿这种吸收衰减最常用的方法是反Q滤波,因此,国内外专家、学者对反Q滤波方法进行了大量研究。反Q滤波方法可以分成用级数展开作近似高频补偿的反Q滤波方法、基于波场延拓的反Q滤波方法和其他反Q滤波方法三大类,对各种反Q滤波方法进行了综述,分析了方法的效率和稳定性,指出了目前反Q滤波方法还存在的一些尚待解决的问题。 相似文献
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稠油采收率计算方法综述 总被引:1,自引:0,他引:1
总结了国内外稠油油藏常用的采收率确定方法,对各方法进行了分析归类,将稠油油藏采收率确定方法主要划分为经验数值类比法、经验公式法、注采关系曲线法等8种,并将稠油采收率计算动态法分为油汽比极限法、水油比极限法和产量极限法。选取6个典型稠油区块采用经验公式计算其采收率,并采用以上8种方法计算了齐40区块的采收率,通过对各方法的计算结果进行的对比分析得出:蒸汽吞吐采收率主要受地质因素影响,蒸汽驱采收率受操作条件的影响较大,在建立采收率计算方法时,应综合考虑操作条件对蒸汽驱的影响;在计算稠油采收率时,应动态与静态相结合,在稠油油藏开发中后期应选用动态法计算采收率,对采收率进行"动态监控"。 相似文献
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Current methods for the prediction of the safe shelf life of gun and mortar propellants are evaluated. This is achieved in a four part approach. Firstly, the current picture of the chemical stability of gun propellants is presented. Secondly, the concepts of stability testing and artificial ageing are reviewed. Thirdly, the traditional and fourthly, the modern testing methods are discussed. In this way, it is possible to identify the reasons for replacing traditional with modern methods and to indicate the methods which would be most appropriate to implement in a country's stability surveillance program for its stored propellants. 相似文献