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1.
本文根据文献提出的几类可逆反应通用的微分动力学方程,建立了热导式量热计中可逆反应动力学的数学模型和不可逆反应动力学的数学模型,运用听导出的一级反应模型,处理了乙酸乙酯与丙酸乙酯在85%乙醇—水混合溶剂中的皂化反应,计算结果与文献值甚为符合,验证了有关理论公式的正确性。  相似文献   

2.
导出了线粒体体外代谢的热动力学方程,探讨了它和指数模型的关系,将演化计算技术引入生物热化学领域,用MTD方程和演化计算技术,对文献报导的八种鱼肝线粒体体外代谢的热动力学参数进行了全局优化。  相似文献   

3.
甲基丙烯酸甲酯聚合动力学和分子量模型及仿真   总被引:2,自引:0,他引:2  
考虑甲基丙烯酸甲酯聚合过程中体积收缩,反应物和生成物的浓度变化,以及由于凝胶、玻璃化和笼闭等效应对各速率常数和物性参数的影响,从基元反应和物料平衡出发,推导了半间歇,有链转移剂参与情况下的聚合动力学和分子量模型。用模型仿真计算了聚合温度、引发剂、溶剂和链转移剂的种类和浓度等对甲基丙烯酸甲酯聚合动力学和聚合过程中分子量变化的影响规律,并与实验和文献数据进行比较。  相似文献   

4.
为评价不同气化方案对常压流化床气化的影响,从化学动力学角度并结合化学平衡建立了流化床气化模型,该模型考虑了煤热解和气化所经历的各反应过程。模型预测结果与文献报道的试验数据吻合较好,气化组分的平方误差和在10%左右,表明该模型可以用来预测各种气化方案对常压流化床气化的气化过程、生成煤气组分和气化效率等方面的影响。  相似文献   

5.
用绝热测试的压力数据计算分解反应的表观活化能   总被引:1,自引:0,他引:1  
绝热量热技术的广泛应用促进了绝热动力学研究的发展.至今为止,绝热动力学的研究仍是以Townsend 和 Tou在1980年提出的绝热动力学方程为基础.他们利用反应物浓度与温度的关系建立动力学模型,从而求得了反应的活化能.但这种方法在反应体系的温度效应不明显时的应用,就受到很大的限制.因此,本文通过建立用压力表示的动力学方程,充分利用绝热量热中的压力数据,提出了一种计算反应活化能的新方法.同时用这种方法计算了过氧化二叔丁基和2-甲基-5-硝基苯磺酸的绝热分解活化能值,并与文献值和其他计算方法所得结果进行了比较.  相似文献   

6.
甲基环己烷的高温燃烧机理及动力学模拟   总被引:2,自引:0,他引:2  
本文根据高碳链烷烃和环烷烃高温燃烧的反应类型,开发了高温燃烧反应机理的自动生成程序ReaxGen,并据此建立了甲基环己烷的高温燃烧详细机理。采用激波管反应器模型开展了动力学模拟,研究了燃烧点火温度、点火压力、燃料摩尔分数和当量比对点火延时的影响。通过绝热燃烧平衡计算,得到产物浓度和绝热火焰温度。动力学模拟结果与文献实验结果及国际上同类机理的模拟结果进行了比较和讨论。  相似文献   

7.
纳米TiO2光催化降解苯酚的动力学研究   总被引:19,自引:1,他引:18  
以125W高压汞灯为光源,以TiO2为催化剂,对不同初始浓度的苯酚水溶液进行了光催化降解实验。同时,考察了不同溶液pH值时的光催化行为。根据实验结果,提出了与文献报道不同的TiO2光催化降解苯酚的零级反应动力学模型。  相似文献   

8.
 利用转篮式无梯度反应器,在工业Fe-Mn催化剂上,在较宽的工业操作相关的反应条件下进行了F-T合成反应动力学研究. 首次提出了利用转篮式无梯度反应器反应气氛和反应温度均一的优势,将烃生成反应动力学的估算从传统的对烃生成和水煤气变换这两类发生在不同活性中心的反应同时进行估算的方法中分离出来,简化了烃生成动力学模型的计算. 在基于亚甲基插入的亚烷基机理动力学模型基础上,考虑到乙烯与催化剂表面强的相互作用,将乙烯和乙烷的生成动力学参数单独计算. 动力学模型计算的链增长、烷烃和烯烃生成的活化能均与文献报道值具有较好的一致性. 由F-T合成动力学模型计算的合成气消耗速率、甲烷生成速率和C5+的生成速率较好地与实验值吻合. 通过动力学模型并结合实验结果分析发现,未考虑除化学反应之外的非本征因素的烯烃再吸附动力学模型不能够正确预测烃产物分布偏离ASF规律及烯烷比随碳数增加而下降的现象.  相似文献   

9.
考虑了烯烃、醇与酸的再吸附及其非本征效应(烯烃、醇与酸在催化剂孔道中的扩散作用、物理吸附及溶解度效应)对产物分布的影响,推导了基于详细反应机理的亚甲基插入的烷基机理F-T合成校正综合动力学模型.利用文献数据对动力学模型进行了回归,获得了与文献报道结果相一致的动力学参数.由校正动力学模型计算的烷烃、烯烃、醇与酸产物分布及烯烃比、醇烃比及酸烃比与实验数据较好地吻合.动力学计算结果表明,在铁锰催化剂上,烷烃、烯烃、醇与酸生成的反应是平行竞争反应,烯烃、醇与酸在催化剂表面的再吸附及二次反应导致产物分布偏离了ASF分布.动力学研究还表明,相同碳数的醇与酸产物在催化剂表面上再吸附及二次反应的机会比相同碳数的烯烃大.通过比较相同碳数的烯烃、醇与酸的分子体积及沸点,指出了在铁锰催化剂上,低碳数的烯烃、醇与酸的再吸附及二次反应对产物分布影响的非本征效应中,烯烃、醇与酸的扩散阻力不是主导效应.  相似文献   

10.
聚丙烯腈热结构化研究进展   总被引:4,自引:0,他引:4  
唐建国 《高分子通报》1995,(4):227-233,216
本文概述了近年来,特别是90年代以来,国内外文献中对聚丙烯腈热结构化反应的原理、产物结构、热结构化动力学模型和产物的机械性能、阻燃性能、电性能和电化学性质学的研究结果。  相似文献   

11.
Simultaneous measurements of zeta-potential for two standard latex suspensions were carried out so as to assess the reliability of each of these measurement techniques and find means for their improvement. Furthermore, syntheses of a reference particle dispersion stabilized sterically in an aqueous medium without any electrostatic effects and measurements of zeta-potential using the reference dispersion as a standard were performed under various experimental conditions. It became apparent that the dense adsorption layer of hydroxypropylcellulose (HPC), with a lower critical solution temperature (LCST), formed on latex particles with a low surface charge density at temperatures higher than the LCST, plays a role in completely shielding the electrostatic effect arising from the surface charge on the bare particles. Such reference particles with zero zeta-potential allow us to determine the electrophoretic mobility of unknown samples at the one-half depth in the electrophoretic cell by subtracting the mobility of the reference sample at the same level. Furthermore, the zeta-potential of the cell wall can be easily determined from the mobility of the reference sample, because the apparent velocity profile of the reference sample indicates the liquid flow velocity in the cell.  相似文献   

12.
定量校准策略是激光剥蚀电感耦合等离子体质谱(AICP-MS)分析技术的重要组成部分,直接影响分析数据的质量.本研究评估了现有玻璃标准物质定值不确定度的相对大小,并探究了NIST、MPI-DING和USGS系列玻璃标准物质之间的基体效应.结果表明,NIST610的定值不确定度优于其它玻璃标准物质,在本实验条件下,NIST、MPI-DING和USGS系列玻璃标准物质之间的基体效应可忽略不计.在此基础上提出了双外标结合基体归一定量校准策略,外标分别为NIST610和StHs6/80-G.此策略克服了由于NIST610主量成分与地质样品差别大而造成的主量元素准确度差以及StHs6/80-G中某些微量元素含量低、定值不确定度较大等缺点.对比采用3种定量校准策略(单外标NSIT610基体归一法、单外标StHs6/80G基体归一法和双外标基体归一法)校准的ML3B-G数据可知,双外标基体归一法有效避免了单外标基体归一法的不足,并提高了分析数据的准确度.采用双外标结合基体归一定量校准策略校准了BCR-2G、CGSG-2和KL-2G中的主量元素和微量元素.结果表明,绝大多数分析数据在定值不确定度范围内,验证了此校准策略的实用性.同时,本研究得到的主量微量元素数据进一步补充了BCR-2G、CGSG-2和KL-2G的定值数据库.  相似文献   

13.
Health-associated reference values are universally needed in clinical chemistry. The aim of this study was to establish the reference intervals of two populations from data obtained by the mass screening of newborn babies and to demonstrate how to determine 95% confidence intervals around the lower and upper limits of reference values from values that are not normally distributed. Biotinidase activities from Belgian (n=260) and Turkish (n=328) populations were measured by fluorometric assay and expressed as 1 IU (1 nmol/(dl min). Neonatal thyroid-stimulating hormone (nTSH) values from Belgian (n=4186) and Turkish (n=1663) populations were also measured by the solid phase two-site fluoroimmunometric assay, the results were given as μU/ml blood. Transformation of data was performed for each parameter. A parametric method was used for determination of reference values of biotinidase activity and the Belgian population was significantly higher than the Turkish population. nTSH reference values were evaluated by an exact non-parametric method, but approximate calculation based on the central limit theorem was also performed for confidence intervals around the reference limits. nTSH values of the Turkish population were found to be significantly higher than for the Belgian population. Rank numbers were found by an exact non-parametric method based upon the assumption of a binomial distribution. This study shows a procedure to define the rank numbers for n>1000 and to obtain reference values with 95% confidence intervals for lower and upper reference limits. Received: 20 July 2002 Accepted: 27 July 2002 Acknowledgements We are grateful to Professor Per Hyloft Peterson, Clinical Biochemist, Odense University Hospital, for his valuable advice and criticism. Also we would like to thank John Pezzullo Associate Professor for Pharmacology and Biostatistics, at Georgetown University Medical Center, for his binomial and approximate calculations. We also want to thank Professor Fatma Kutay, Clinical Chemist, Ege University Medical School and Hospital, for her contributions. This investigation was supported in part by a short term FEBS (Federation European Biochemical Society) fellowship grant. Presented at the European Conference on Quality in the Spotlight in Medical Laboratories, 7–9 October 2001, Antwerp, Belgium Correspondence to T. Tanyal?ın  相似文献   

14.
正确使用标准物质/标准样品   总被引:2,自引:0,他引:2  
介绍了标准物质与标准样品、有证与非有证标准物质/标准样品的区别与联系,国內外有证标准物质/标准样品的判断依据,标准物质/标准样品及其证书的科学使用。对正确理解和使用标准物质/标准样品提出了一些建议。  相似文献   

15.
建立了小麦粉中细交链孢菌酮酸(TeA)和腾毒素(TEN)标准物质的研制和定值方法,为开展粮食中交链孢霉毒素基体标准物质的研制提供重要方法学借鉴。该标准物质样品为天然污染交链孢霉毒素的小麦籽粒,定值目标物为TeA和TEN,采用同位素稀释-液相色谱-串联质谱法(ID-LC-MS/MS)进行定值测量,多个实验室合作定值。所研制的标准物质具有常温避光保存、定值不确定度小等特点。该标准物质是目前国际上唯一一种天然污染TeA和TEN的小麦粉标准物质,可用于食品安全风险监测、产品质量检测等领域相关分析方法的评价和测量质量控制等。  相似文献   

16.
An alternative calibration procedure for use when performing carbon isotope ratio measurements by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) has been developed. This calibration procedure does not rely on the corrections in-built in the instrument software, as the carbon isotope ratios of a sample are calculated from the measured raw peak areas. The method was developed for the certification of a urine reference material for sports drug testing, as the estimation of measurement uncertainty is greatly simplified. To ensure that the method is free from bias arising from the choice of calibration material and instrument, the carbon isotope ratios of steroids in urine extracts were measured using two different instruments in different laboratories, and three different reference materials (CU/USADA steroid standards from Brenna Laboratory, Cornell University; NIST RM8539 mineral oil; methane calibrated against NIST RM8560 natural gas). The measurements were performed at LGC and the Australian National Measurement Institute (NMI). It was found that there was no significant difference in measurement results when different instruments and reference materials were used to measure the carbon isotope ratio of the major testosterone metabolites androsterone and etiocholanolone, or the endogenous reference compounds pregnanediol, 11- ketoetiocholanolone and 11β-hydroxyandrosterone. Expanded measurement uncertainties at the 95% coverage probability ranged from 0.21‰ to 1.4‰, depending on analyte, instrument and reference material. The measurement results of this comparison were used to estimate a measurement uncertainty of δ(13)C for the certification of the urine reference material being performed on a single instrument using a single reference material at NMI.  相似文献   

17.
研制4,9-脱水河豚毒素国家标准样品。以河豚鱼卵巢为原料,提取制备4,9-脱水河豚毒素,采用红外光谱(IR)、高分辨质谱和核磁共振谱(NMR)进行结构确证。样品分装成140瓶后,采用柱后衍生–高效液相荧光法进行均匀性、稳定性检验和定值分析。从样品中随机抽取15瓶进行均匀性检验,经F检验表明在95%的置信区间范围内样品均匀性良好;稳定性考察按照40℃加速试验稳定性(6个月)进行,结果表明在考察期间内样品稳定性良好;标准样品经国内8家具有分析资质的实验室进行协同定值,并评定了定值结果的不确定度,4,9-脱水河豚毒素标准样品定值结果为97.77%,相对扩展不确定度为0.4%(k=1.96)。该标准样品达到国家标准样品的技术要求,可用于有关脱水河豚毒素的方法校正和质量控制。  相似文献   

18.
Nine coppery alloys and five basaltic glasses have been quantitatively evaluated as the reference materials to employ in electron probe X-ray microanalysis. The optimum conditions for measurements were selected considering the dependence of intensity and detection limit on the conditions of the X-ray radiation excitation and analytical signal recording. The homogeneity of basaltic glasses and coppery alloys has been examined. The dependence of electron probe X-ray microanalysis accuracy on the homogeneity of reference materials was studied in the reference materials of coppery alloys.Six data sets comprising the average concentrations, standard deviations, relative standard deviations, confidence interval and the z-score of data quality were calculated for 50 control samples: 10 alloys, 14 glasses, 2 metals, 24 minerals and oxides. The average compositions of every control sample were derived in 8–16 analyses. The measured values were corrected for matrix effects applying the original program. These series of concentrations have been compared with each other and with the certified/recommended values using 2-pair selective Student's t-test.The results gained from both laboratory reference materials and certified glass reference materials show comparable accuracy. The quality of all available results complies with the “applied geochemistry” category of performance (2nd category). The laboratory reference materials give comparable accuracy to certified reference materials and can be used for calibrating microprobe techniques, as well as data quality control. The application of laboratory reference materials in microanalysis of silicate minerals and coppery alloys allows reliable analytical data to be acquired. The applications in mineralogy and metallurgy can be extended successfully to the targets when certified reference materials are not available.  相似文献   

19.
In this work the possibility to use a simple and easily available laboratory device—routine ultrasonic bath—has been evaluated for total metal determination in sediments from different origin. The investigated instrumental parameters were time and temperature, whereas power was maintained constant set at 100% of nominal power. Four different sets of parameters were applied on a lake sediment reference material (RM), the results obtained for five elements—Cd, Cr, Cu, Ni and Zn—were statistically compared with those obtained by a previously optimised microwave acid digestion procedure on the same material. The optimal set of parameters—30 min sonication at ambient temperature—was chosen, and then applied to other five sediment RMs from different origin. In this case four additional elements—As, Pb, V and Fe—were also determined and the results were compared with reference and microwave values.The results obtained by the ultrasound digestion procedure were higher than 80% of the reference and/or microwave values in 40 out of 44 cases. In any case, the results obtained by ultrasonic procedure were statistically comparable to reference values (mean of means of interlaboratory exercises or certified values) in the 84% of the cases.  相似文献   

20.
This inter-laboratory comparison study was arranged for 28 laboratories from different public and private sector organizations in Pakistan having wastewater testing capabilities aimed at improving the quality and comparability of test results. This national inter-laboratory study was started in December 2003 and completed in July 2004. Laboratories were invited to analyze the wastewater collected from printed circuit board (PCB) industry for lead and copper contamination. The samples fulfill the criteria for homogeneity and stability as done by the reference laboratory. The results obtained from participating laboratories were analyzed in terms of Hampel Test for outliers, while the performance evaluation of the participating laboratories was done on the basis of Z-score. An assigned value derived from the participant's results was compared with a reference value provided by a reference laboratory. Overall >50% of the participating laboratories have shown good performance in this PT-program  相似文献   

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