Measurement and Correlation of Isobaric Vapor-Liquid Equilibrium of Three Binary Systems Containing Chlorobenzene at 50.00 and 101.33 kPa

Isobaric vapor-liquid equilibrium(VLE) data for three binary systems, chlorobenzene + N,N-dimethylformamide, chlorobenzene + furfural, and chlorobenzene + benzaldehyde, were measured at 50.00 and 101.33 kPa using a modified Rose-Williams still. Gas chromatography was used to analyze the compositions of the samples and no azeotropic behavior was found. All of the measured VLE values were checked by the semi-empirical method proposed by Herington and the point-to-point Van Ness test method modified by Fredenslund. The experimental data were correlated by using the Wilson, the non-random two-liquid and universal quasi-chemical activity coefficient models. The corresponding parameters for the three models were obtained.     

光催化降解甲基橙过程的评价方法研究

以300W汞灯为光源,纳米TiO2为光催化剂,甲基橙为目标降解物,以分光光度法测定其脱色率,以重铬酸钾法测定其COD降解率,研究了在不同溶液pH值、甲基橙初始浓度及TiO2投加量等条件下的甲基橙光催化降解效率．结果表明,甲基橙溶液脱色率和COD降解率并不一致,脱色比COD降解更容易发生;将脱色率、COD降解率等指标的变化综合考虑,才能更全面准确地判断光催化反应的效率．     

基于高职“化工生产技术”赛项的乙醇浓度定量方法

用气相色谱归一化法和外标法相结合的定量分析方法,分别测定化工生产技术竞赛原料和蒸馏产品中乙醇的含量。结果表明,原料测定的乙醇线性范围为10%~15%(质量浓度),相关系数达到0.9997。蒸馏产品测定的乙醇线性范围为80%~92%(质量浓度),相关系数达到0.99995。线性关系良好,精密度高,而且测定结果的相对误差小,准确度高。此复合型的定量方法具有简单、快速、准确的优点,尤其适合竞赛,可确保竞赛成绩的公正性。     

Excess Molar Volumes and Viscosities of Binary Mixture of Diethyl Carbonate ＋ Ethanol at Different Temperatures

Densitiesandviscositiesofliquidmixturesareimportantbothinpracticeandtheory.Inpractice,densitiesarenecessaryinalotofchemicalengineer ingcalculations(i.e.dimensionofstoragedeposits,designofcondensersandboilers,etc.)andalsoin determiningthedynamicviscosity.Thelatterisre quiredintheresolutionofmanyengineeringproblemsinvolvingheattransfer,masstransferandfluidflow.Intheory,density,excessvolumeandviscositycanbeusedtostudytheinteractionspresentinmixtures,suchasdispersionforces,hydrogenbondinginterac t…     

Isobaric vapor-liquid equilibrium for toluene, 3-methylthiophene and N-formylmorpholine at 101.33 kPa

Isobaric vapor-liquid equilibrium(VLE)data were measured for binary mixtures of toluene+N-formylmorpholine,toluene+3-methylthiophene and 3-methylthiophene+N-formylmorpholine at 101.33 kPa.The VLE data ...     

Mo掺杂纳米TiO_2光降解甲基橙的动力学模型

通过溶胶-凝胶法制备了Mo不同掺杂量的纳米TiO2光催化剂,进行了UV-Vis分析,并在紫外光源下对降解甲基橙光催化活性进行了测定.最后建立L-H模型和GM(1,1)模型,考查了Mo/TiO2对甲基橙的降解动力学,并对模型进行了比较.结果表明,纳米TiO2当煅烧温度为500℃时,Mo的最佳掺杂量为0.05 mol%.L-H模型对有些Mo掺杂纳米TiO2光催化降解甲基橙存在偏差,且Andrews型稳健回归优于最小二乘算法的模拟结果.而GM(1,1)模型对Mo掺杂纳米TiO2光催化降解甲基橙能进行很好的实验模拟.     

Effect of Marangoni Convection on Mass Transfer in Liquid Phase

Marangoni effectis of interestto the chemical en-gineers from both scientific and practical points ofview[1—6]. The Marangoni convection contributes tothe renewal of the interfacial surface and is capable ofincreasing the mass transfer rate, resulting in intensi-fication of separation processes such as distillation,extraction, absorption, and desorption. The theoretical studies of Marangoni instability inthe past were focused on determining the critical tran-sition point. The critical condit…     

Mo掺杂纳米TiO2光降解甲基橙的动力学模型

通过溶胶-凝胶法制备了Mo不同掺杂量的纳米TiO2光催化剂,进行了UV—Vis分析,并在紫外光源下对降解甲基橙光催化活性进行了测定．最后建立L-H模型和GM（1,1）模型,考查了Mo／TiO2对甲基橙的降解动力学,并对模型进行了比较．结果表明,纳米TiO2当煅烧温度为500℃时,Mo的最佳掺杂量为0．05mol％,L-H模型对有些Mo掺杂纳米TiO2光催化降解甲基橙存在偏差,且Andrews型稳健回归优于最小二乘算法的模拟结果．而GM（1,1）模型对Mo掺杂纳米TiO2光催化降解甲基橙能进行很好的实验模拟．     

径向基函数神经网络与稀土卤化物标准生成焓的研究

研究并应用径向基函数神经网络(RBF-network)对稀土卤化物标准生成焓进行定量建模,相关系数r达到0.9985,样本误差较小,显现了神经网络方法在该领域的优势.交互预测结果证明模型具有好的稳定性和泛化性能,对7个未知样本所作的预测有一定参考价值.     

十全大补汤的高效液相色谱指纹谱图研究

基于HPLC方法,本文研究了十全大补处方乙醚萃取液的HPLC指纹谱图和提取工艺稳定性的表征指标。发现了5个色谱峰能够较为稳定地出现在所测样本的色谱图中,它们表现出了相同或极其相近的相对保留时间,因此可以作为指纹谱图的良好的定性特征。对全光谱分别以均值光谱和中位数光谱为标准进行相似性评价,其相关系数和相合系数均具有较强的相似性,大多数表现出85%以上的相似度。表明本文方法可以较为理想地用于复方提取物的质量评价和工艺过程的质量控制。     

不同检测系统总胆固醇、甘油三酯测定的对比分析

通过对不同检测系统进行方法对比分析,探讨各系统之间检测总胆固醇(TCHOL)、甘油三酯(TG)结果是否具有可比性。参照NCCLS《EP9-A文件》的要求,以可溯源的检测系统为目标检测系统,均采用酶法测定TCHOL、TG,对本院3个不同检测系统进行朗道质控物(水平2和水平3)各测定21次和测定新鲜血清标本40份。朗道质控物和新鲜血清标本TCHOL、TG测定经随机区组设计资料的方差分析,各检测系统间的差异均有显著性(P<0.001)。各检测系统测定新鲜血清标本TCHOL、TG可靠性系数α分别为0.9977、0.9990,各系统间的相关系数均大于0.975。各检测系统测定TCHOL、TG的精密度CV均小于5%,以可溯源的检测系统1为目标检测系统,临床可接受性能评价TG检测系统2和系统3均未超出临床接受范围,而TCHOL均超出临床接受范围。3个不同检测系统测定TG结果具有可比性;而TCHOL结果不具有可比性,需采取整改措施。当同一实验室同一检验项目存在二个以上的检测系统时,应进行方法比对和偏倚评估。     

H_2O_2-抗坏血酸均相催化氧化法处理甲基橙

采用一种新的均相催化氧化体系——H2O2-抗坏血酸体系处理高浓度甲基橙模拟偶氮染料废水。通过改变过氧化氢、抗坏血酸投加量及溶液pH值、反应温度、时间等影响因素的实验与分析,研究了该体系对甲基橙脱色率的影响,并初步探讨了氧化降解的机理。结果表明,该体系能有效地使高浓度(1900mg/L)甲基橙溶液脱色,脱色率大于98%。     

应用量化参数研究CCK受体拮抗剂的结构与活性的相关性

应用MM+分子力学法对24个CCK受体拮抗剂类似物进行结构优化,然后应用量子化学AM1法计算了24个CCK受体拮抗剂类似物的部分量化参数,并通过逐步回归分析方法建立了量化指数与CCK受体拮抗剂活性之间的定量相关模型,取得了良好的结果,其模型相关系数为R=0.886;继以留一法(Leave-one-out,LOO)进行交互检验,复相关系数为R2cv=0.539,说明定量相关模型具有良好的稳定性和预测能力.发现CCK受体拮抗剂的活性部位主要在分子的A、B环及其支链C21和N20上.     

甲基橙褪色光度法测定加碘盐中微量碘

基于硫酸介质中,在溴化钾催化作用下,碘酸根氧化甲基橙褪色作用,据此建立了测定碘的动力学光度法.结果表明,最大吸收波长为507 nm时,碘酸钾浓度在0~1.6 mg/L内呈线性关系,表观摩尔吸收系数为9.17×104L.mol-1cm-1.方法用于加碘盐中碘(V)的测定,结果令人满意.     

Experimental adsorption equilibrium study and comparison of zeolite with water and ethanol for cooling systems

INTRODUCTION In the past few decades, adsorption processes have been used exclusively for gas separation and purification purposes. It is only recently that this phenomenon has been exploited to produce cooling and heating. As regulations aiming at phasing out the CFCs are being implemented, thermally driven sorp-tion refrigeration machines are emerging as an at-tractive alternative to electrical vapor compression machines that produce no harmful effect on the en-vironment since their w…     

Measurement of soluble solids content in watermelon by Vis/NIR diffuse transmittance technique

INTRODUCTION Determination of fruit and vegetable quality is very important for both producers and processors. Watermelon as a delicious fruit has been widely ac-cepted in the world and its internal quality is impor-tant for consumers and merchants. The current fa-vorite way for checking a watermelon is to sense sound or vibration by slapping or rapping it. It is time consuming, tedious, and subject to error. Several studies on assessing the quality of watermelon based on its acoustic o…     

取代苯胺和苯酚类化合物的结构表征与结构-活性定量相关关系研究

为了评估和测定有机污染物取代苯胺和苯酚类化合物的生物毒性 ,在分子电性距离矢量的基础上引入正辛醇 水分配系数对这类化合物进行了结构表征 ,建立了取代苯胺和苯酚类化合物的结构 -与毒性之间的定量数学模型 (R =0 96 0 ) ,并通过逐步回归分析选出 4个参数建立一新的QSAR方程 (R =0 95 8) ,这些方程可以用来进行该类化合物危害性的定量评估和预测     

甲基异丁基甲酮在水-正辛醇中分配系数的测定

实验以绿色化学理念为主导思想，在测有机污染物的正辛醇-水分配系数的实验中用毒性小的甲基异丁基甲酮（4-甲基-2-戊酮）代替常规实验中使用的对环境和人类有害的对二甲苯，从而减少污染，避免危害，而且取得了很好的教学效果。     

Estimating the Coefficient of Cross-Validity in Multiple Regression: A Comparison of Analytical and Empirical Methods

In predictive applications of multiple regression, interest centers on the estimation of the population coefficient of cross-validation rather than the population multiple correlation. The accuracy of 3 analytical formulas for shrinkage estimation (Ezekiel, Browne, & Darlington) and 4 empirical techniques (simple cross-validation, multicross-validation, jackknife, and bootstrap) were investigated in a Monte Carlo study. Random samples of size 20 to 200 were drawn from a pseudopopulation of actual field data. Regression models were investigated with population coefficients of determination ranging from .04 to .50 and with numbers of regressors ranging from 2 to 10. For all techniques except the Browne formula and multicross-validation, substantial statistical bias was evident when the shrunken R ² values were used to estimate the coefficient of cross-validation. In addition, none of the techniques examined provided unbiased estimates with sample sizes smaller than 100, regardless of the number of regressors.     

固体碱催化固定床法生产生物柴油的工艺研究(英文)

对固体碱催化剂催化固定床法工业化生产生物柴油进行了模拟.顺利进行了小试实验,并建立了生物柴油合成的酯交换反应的动力学模型,该模型能较为准确地描述酯交换反应.通过对文献中的气液平衡数据的回归得到了生物柴油的安托因方程.选择NRTL模型对脂肪酸甲酯(FAME)-甲醇-甘油体系进行描述,得到了体系NRTL的二组分参数,利用Aspen Plus对该体系液液平衡数据(LLE)的回归得到了三组分相图.为了预测固定床工艺生产在工业规模放大1 000倍后的效果,Aspen Plus对2个流程进行了仿真模拟,预测物料和能量消耗.模拟结果表明,与先前文献报道的数据相比,每小时生产每吨生物柴油至少可以减少350.42 kW的能量消耗.