激光全息干涉法测量甘氨酸、L-丙氨酸、L-缬氨酸和异亮氨酸液相扩散系数的研究

The diffusion coefficients of aqueous solutions ofglycine, L-alanine, L-valine and L-isoleucine at 298.15 K were determined by holographic interferometry with accuracy and promptness while without disturbance. The density and viscosity of these solutions were also determined. According to original Gordon model, a model for correlating the diffusion coefficients of amino acids in aqueous solutions was developed and applied. The results showed that this model provided significant convenience in correlation of diffusion coefficients for amino acids system.     

L-精氨酸在非牛顿流体中的扩散系数

L-Arginine is an important component of amino acid injection. Its diffusion in body fluid and blood is of key importance to understand drug diffusion and drug release. As a fundamental demand for study and being a considerably valuable reference for application, in this study, the diffusion coefficients of L-arginine in polyacrylamide（PAM） aqueous solution used as non-Newtonian fluid similar to blood and body fluid were measured using a holographic interferometer. The effects of interaction among molecules and solution concentration on diffusion were analyzed and discussed, respectively. Based on the obstruction-scaling model, a novel modified model was presented for predicting diffusivity of solute in non-Newtonian fluid. Good agreement was achieved between the calculated value and the experimental data.     

氨基酸在水溶液中的扩散系数

There are still limited experimental data of liquid diffusion coefficients in literature. Therefore, the experimental investigation and prediction model are of practical and theoretical significance. The diffusion coefficients of L-serine, L-threonine, L-arginine, in aqueous solution at 298. 15 K were measured respectively by holographic interferometer. The affecting factors of molecular structure and polarity were analyzed and discussed. Finally, a modified semi-empirical model for correlating the diffusion coefficients of solid organic compounds in aqueous solutions at 298. 15 K was proposed with an adjustable parameter added. The average deviation between model prediction values and experimental ones is less than 0.2%, which shows a considerably satisfactory accuracy.     

苏氨酸水溶液在298.15K到328.15K区间液相扩散系数的测定和关联

The diffusion coefficients of aqueous L-threonine solutions were determined from 298.15K to 328.15K by the metallic diaphragm cell method with accuracy, promptness and convenience. Meanwhile, the densities and viscosities of the solutions were also determined and correlated. Based on a seml-empirical model for correlating the diffusion coefficients of some amino acids in their aqueous solutions, a new semi-empirical model for correlating the diffusion coefficients involving temperature was provided, which is more comprehensive and less experiment dependent compared to the previous model. The fitting results are satisfactory. Compared to a former model for correlating the diffusion coefficients of solid organic salts in their aqueous solutions, this model provides significant improvement in correlation of diffusion coefficients with different temperatures avoiding arduous work.     

在同心和偏心圆环中有屈服应力的黏塑性流体流动的模型和数值模拟(英文)

Numerical solution of yield viscoplastic fluid flow is hindered by the singularity inherent to the Herschel-Bulkley model.A finite difference method over the boundary-fitted orthogonal coordinate system is util-ized to investigate numerically the fully developed steady flow of non-Newtonian yield viscoplastic fluid through concentric and eccentric annuli.The fluid rheology is described with the Herschel-Bulkley model.The numerical simulation based on a continuous viscoplastic approach to the Herschel-Bulkley model is found in poor accordance with the experimental data on volumetric flow rate of a bentonite suspension.A strict mathematical model for Herschel-Bulkley fluid flow is established and the corresponding numerical procedures are proposed.However,only the case of flow of a Herschel-Bulkley fluid in a concentric annulus is resolved based on the presumed flow structure by using the common optimization technique.Possible flow structures in an eccentric annulus are pre-sumed,and further challenges in numerical simulation of the Herschel-Bulkley fluid flow are suggested.     

Measurement and correlation of solubility of diosmin in four pure solvents and β-cyclodextrin solution at 298.15 K to 333.15 K

The aim of present study was to measure and correlate the solubility of poorly water-soluble flavonoid diosmin in water, ethanol, isopropyl alcohol (IPA), polyethylene glycol-400 (PEG-400) andβ-cyclodextrin (β-CD) aqueous solution (0.02 mol·L-1). The solubility of diosmin was measured using the shake flask method from (298.15 to 333.15) K at atmospheric pressure. The experimental solubilities of diosmin were regressed by the modified Apelblat model with a relative deviation in the range of 0.048%to 5.940%. The correlation coefficients were observed in the range of 0.9957 to 0.9995. The solubility of diosmin was found to be increased with temperature in all sample matrices investigated. The mole fraction solubility of diosmin was found to be higher inβ-CD aqueous solution and PEG-400 as compared to water, ethanol and IPA. Based on solubility data of present study, diosmin was considered as practical y insoluble in water, insoluble in ethanol&IPA and soluble in PEG-400 andβ-CD aqueous solution.     

Prediction of Swelling Behavior of AT-Isopropylacrylamide Hydrogels in Aqueous Solution of Sodium Chloride

In this paper, a model is presented to correlate and predict the swelling behavior of hydrogels in aqueous solutions of electrolytes. The model is a combination of VERS-model, "phantom network" theory and "free-volume" contribution. The VERS-model is used to calculate Gibbs excess energy; "phantom network" theory to describe the elastic properties of polymer network, and "free-volume" contribution to account for additional difference in the size of the species. To test the model, a series of N-isopropylacrylamide based hydrogels are synthesized by free radical polymerization in oxygen-free, deionized water at 25℃ under nitrogen atmosphere. Then, the degree of swelling of all investigated gels as well as the partition of the solute between the gel phase and the surrounding coexisting liquid phase are measured in aqueous solution of sodium chloride. The model test demonstrates that the swelling behavior correlated and predicted by the model agrees with the experimental data within the experimental uncert     

288.15K-308.15K(Poloxamerl88+乙醇/丙酮+水)三元体系的密度和黏度

The densities and viscosities of ternary systems(Poloxamer 188+ethanol/acetone+water)were meas- ured at 288.15,293.15,298.15,303.15,308.15 K and atmospheric pressure for different mass fractions of Poloxamer 188(0 to 0.02)in aqueous solution and different solvent volume fractions of ethanol/acetone(0 to 0.3)in Poloxamer 188 aqueous solution.The densities were measured by a pycnometer,while the viscosities were measured using two Ubbelohde capillary viscometers.The correlations of density and viscosity of these ternary systems are obtained by fitting the experimental data at different temperatures,mass fractions and volume fractions.     

1,3-二甲基咪唑四氟硼酸盐的合成及其水溶液的蒸气压测定

In absorption cycles,ionic liquid(IL)1,3-dimethylimidazolium tetrafluoroborate([Dmim]BF4)may be a promising absorbent of working pair using water as refrigerant.The vapor pressures of[Dmim]BF4 aqueous solution were measured with the boiling-point method in the temperature range from 312.25 to 403.60 K and in the mass concentration range of 65%to 90%of[Dmim]BF4.The experimental data were correlated with an Antoine-type equation and the Non-Random Two-Liquid(NRTL)model,and the average absolute deviations between the experimental and calculated values were 1.06%and 1.15%,respectively.For the[Dmim]BF4 aqueous solution,the experimental vapor pressures show negative deviations from the calculated data with Raoult’s law.For higher mass concentration of the IL,the deviation is more negative.In addition,the vapor pressures,the hydrophilicity and the solubility of[Dmim]BF4 aqueous solutions were compared with those of[Dmim]Cl aqueous solutions and [Bmim]BF4 aqueous solutions at IL-mole fraction of 0.20.     

Modified DIX model for ion-exchange equilibrium of L-phenylalanine on a strong cation-exchange resin☆

L-phenylalanine, one of the nine essential amino acids for the human body, is extensively used as an ingredient in food, pharmaceutical and nutrition industries. A suitable equilibrium model is required for purification of L-phenylalanine based on ion-exchange chromatography. In this work, the equilibrium uptake of L-phenylalanine on a strong acid-cation exchanger SH11 was investigated experimental y and theoretical y. A modified Donnan ion-exchange (DIX) model, which takes the activity into account, was established to predict the uptake of L-phenyl-alanine at various solution pH values. The model parameters including selectivity and mean activity coefficient in the resin phase are presented. The modified DIX model is in good agreement with the experimental data. The optimum operating pH value of 2.0, with the highest L-phenylalanine uptake on the resin, is predicted by the model. This basic information combined with the general mass transfer model wil lay the foundation for the prediction of dynamic behavior of fixed bed separation process.     

十二烷基苯磺酸钠-乙醇-水体系固液相平衡

引　言烷基苯磺酸盐是目前已发现的高效廉价驱油用表面活性剂[1,2 ] ,在用于三元 (表面活性剂、碱和聚合物 )复合驱技术时[1,2 ] ,体系中常加入醇类助剂 ,以进一步降低油水界面张力和扩大体系的均相区[3,4 ] .在进行驱油体系配方筛选时 ,急需相平衡知识的理论指导 .本文实验测定了 2 98.15～318.15Ｋ十二烷基苯磺酸钠 (ＳＤＢＳ)在乙醇 -水混合溶剂中的溶解度 ,实验结果用溶解度模型关联 .1　实验测定用浊度法测定溶解度 ,实验装置和操作步骤见文献 [5 ],测定时控温精度为± 0 .1Ｋ .样品为 :①ＳＤＢＳ ,分析纯 ;②无水乙醇 ,分析纯 ;③氢…     

激光全息干涉法测量液相质扩散系数数字图像处理的研究

用He-Ne激光器、CCD和图像采集系统等仪器设备,搭建了数字激光全息干涉法测量液相质扩散系数的实验系统,并测试获得了浓度为0.33 mol/l KCl水溶液在298.15 K温度下的全息干涉图像,采用了图像增强、全息干涉条纹图再现及相位展开等数字图像处理过程的关键技术对全息干涉图进行处理,得到了相位展开后物光相位差,经换算后获得了该溶液的质扩散系数.为化工工程上研究替代制冷荆急需的质扩散系数测量提供了有效的方法.     

The activity coefficients of glycine,DL‐Serine and DL‐Valine in aqueous solutions containing nitrates at 298.15 K

An electrochemical method was used to measure the mean activity coefficients of amino acids in water‐electrolyte‐amino acid systems. The amino acids were glycine, DL‐serine and DL‐valine and the electrolytes were KNO₃ and NaNO₃. The activity coefficients of the electrolytes were obtained from the e.m.f measurements in an electrochemical cell with an anion and a cation ion‐selective electrodes, each measured versus a double junction reference electrode at 298.15 K. The activity coefficients of the amino acids in the ternary systems were obtained from those of the electrolyte according to the cross differential relation. A simple semi‐empirical model based on a modification of a more complex form, derived from perturbation theory, was used to correlate the activity coefficients in binary aqueous solutions and in ternary systems.     

数字全息干涉法测量液相质扩散系数的研究

介绍数字全息干涉法测量原理.设计并搭建基于数字全息干涉法和新的扩散槽测量质扩散系数的实验系统,并使用此系统测量了浓度为0.33 mol/l的KCl水溶液在温度为291.8、294.7、298.8、299.8、305.4、308.5、315.2 K条件下的质扩散系数,实验结果表明实验值和文献参考值之间相对偏差绝对值的平均数为1.3%,验证了试验系统的精确性和可靠性.最后,在此系统上测量了浓度为0.1 mol/1的蔗糖水溶液在288.15～338.15 K温度范围内的质扩散系数.为测量工程上急需新型燃料替代工质和新型制冷剂替代工质的质扩散系数提供了一种新的有效方法.     

鼓泡反应器中幂律型流体流动与传质特性

很多废水处理装置涉及非牛顿型流体中的多相流动和传质问题,研究其中的气液传质过程有助于实现装置的优化设计和高效节能运行。以鼓泡反应器内清水和不同质量分数的羧甲基纤维素钠（CMC）水溶液为实验对象,分别研究气相表观气速和液相流变特性对气泡尺寸分布、全局气含率和体积氧传质系数的影响。实验结果表明,液相的流变特性对其传质特性参数均有较大影响。与清水相比,CMC水溶液中气泡平均直径和分布范围更大;清水和CMC水溶液的全局气含率均随表观气速的增加而增大;CMC水溶液的体积氧传质系数随CMC水溶液质量分数的增加而减小。基于实验研究,得出修正的体积氧传质系数公式和适用于幂律型非牛顿流体流动体系氧传递过程的无量纲关联式,可很好地实现非牛顿流体流动的废水处理装置中气液传质参数的计算。