5-(1-甲基-1-甲氧羰基甲氧基)间苯二甲酸二甲酯的合成

研究了5-(1-甲基-1-甲氧羰基甲氧基)间苯二甲酸二甲酯的合成反应,优化了合成的条件。通过对比实验,筛选了制备的最佳合成条件:以5-羟基间苯二甲酸为原料,经过酯化,Williamson反应以60%的产率制备了5-(1-甲基-1-甲氧羰基甲氧基)间苯二甲酸二甲酯。通过对其旋光性的测试,证明了该化合物的外消旋结构,推测该反应经历了SN1反应历程,表征了其结构。     

二乙二醇甲乙醚的合成及其合成条件优化

以二乙二醇单乙醚(DEGME)和氯甲烷为基本原料,氢氧化钠为催化剂、苯为带水剂,通过Williamson反应合成了二乙二醇甲乙醇(DEGMEE);用正效实验法对DEGMEE的合成条件进行了优化,气相色谱法分析了产品中DEGMEE的含量、FT IR和1H NMR法表征了产物结构。实验结果表明适宜的反应条件为:反应温度为60.0°C、醚化时间为4.0 h、n(CHCl)/n(DEGME)=1.15、n(NaOH)∶(DEGME)=1.30;在此条件下二乙二醇甲乙醚的收率可达93%以上。     

聚乙烯醇基质球状疏水吸附树脂的制备及表征

以聚乙烯醇(PVA)为原料,甲醛作交联剂,采用悬浮聚合法制备了球状交联PVA颗粒。并对水溶液中PVA含量、表面活性剂种类、反应温度等影响因素进行了考察,最佳工艺条件为:PVA质量分数15%,表面活性剂V(Span-80):m(油酸钠)为2 mL/g,在88～92℃进行悬浮聚合。以球状交联PVA颗粒为基质,用醇钠溶液预处理后,通过Williamson醚化反应制备了球状疏水吸附树脂,最佳醚化反应条件为:醇钠溶液浓度2.0 mol/L,NaOH浓度4mol/L,醚化温度50～60℃。     

Design and testing of varying magnetic field effect in a pulsatility blood flow of viscoelastic material: Flexibility analysis in a curved channel

This paper attempts to investigate the peristaltic mechanism of Williamson fluid in a pipe flow under the influence of variable radial magnetic field along with slip effects and compliant walls. Viscous dissipation and thermophoresis effects are also considered. The solutions of coupled nonlinear ordinary differential equations are obtained using the perturbation technique and results are graphically represented. The effects on heat, mass, velocity, and heat transfer coefficient are studied under various pertinent parameters. The outcomes of the present model can be applied in various fields of biomedical engineering where smart peristaltic pumps can be engineered to transport the biological fluids without any contamination. The scope of the present article is valuable in explaining the blood transport dynamics in small vessels while considering the important wall features with chemical reaction characteristics.     

均质脂肪醇聚氧乙烯醚羧酸盐的合成及性能研究

以脂肪醇为原料，通过Wiliamson合成法合成了聚氧乙烯醚加成数n=2,3,4的均质醇聚氧乙烯醚，并利用羧甲基化法合成了聚氧乙烯醚加成数n=2,3,4的均质脂肪醇聚氧乙烯醚乙酸钠，经减压蒸馏提纯，薄层色谱显示均为单一班点，综合表面活性测试结果表明，当脂肪基的碳链长度相同时，随着聚氧乙烯醚加成数的增加，均质脂肪醇聚氧乙烯醚羧酸钠盐的表面活性增加，当聚氧乙烯醚加成数相同时，随着脂肪基的碳链长度的增加，均质脂肪醇聚氧乙烯醚羧酸钠盐的表面活性增加。     

Evaluation of an Nd doping effect on characteristic properties of tin oxide

In the present work, transparent and conductive Nd doped SnO₂ thin films were deposited via spray pyrolysis. Crystallographic, morphological, optical and electrical characterizations of SnO₂ were researched as a function of Nd doping. The XRD analysis indicated the films had tetragonal cassiterite tin oxide structure and (211) preferential direction for NdTO-0, NdTO-1, NdTO-2 and NdTO-3 samples changed to (110) plane for NdTO-4 and NdTO-5 samples. The crystalline size and strain analysis were made by using a Williamson–Hall method. The SEM micrographs showed that all films had homogenously scattered pyramidal and small densely nanoparticles. The optical analysis indicated optical band gap value of undoped film increased with 1 at% Nd doping and then it decreased with more Nd content. The Hall measurements indicated that the highest electrical conductivity was obtained for 2 at% Nd doping content.     

Entropy analysis of unsteady MHD three-dimensional flow of Williamson nanofluid over a convectively heated stretching sheet

This article addresses an investigation of the entropy analysis of Williamson nanofluid flow in the presence of gyrotactic microorganisms by considering variable viscosity and thermal conductivity over a convectively heated bidirectionally stretchable surface. Heat and mass transfer phenomena have been incorporated by taking into account the thermal radiation, heat source or sink, viscous dissipation, Brownian motion, and thermophoretic effects. The representing equations are nonlinear coupled partial differential equations and these equations are shaped into a set of ordinary differential equations via a suitable similarity transformation. The arising set of ordinary differential equations was then worked out by adopting a well-known scheme, namely the shooting method along with the Runge-Kutta-Felberge integration technique. The effects of flow and heat transfer controlling parameters on the solution variables are depicted and analyzed through the graphical presentation. The survey finds that magnifying viscosity parameter, Weissenberg number representing the non-Newtonian Williamson parameter cause to retard the velocity field in both the directions and thermal conductivity parameter causes to reduce fluid temperature. The study also recognizes that enhancing magnetic parameters and thermal conductivity parameters slow down the heat transfer rate. The entropy production of the system is estimated through the Bejan number. It is noticeable that the Bejan number is eminently dependent on the heat generation parameter, thermal radiation parameter, viscosity parameter, thermal conductivity parameter, and Biot number. The skillful accomplishment of the present heat and mass transfer system is achieved through the exteriorized choice of the pertinent parameters.     

Effects of nonlinear thermal radiation over magnetized stagnation point flow of Williamson fluid in porous media driven by stretching sheet

In this study, the stagnation point flow of a magnetized Williamson fluid past a stretching sheet in the presence of nonlinear thermal radiation and buoyancy effect is studied. The present situation is remodeled using similarity transformation that transforms the flow model of partial differential equations into the set of nonlinear ordinary differential equations. The fourth-order Runge-Kutta scheme and shooting method are employed to solve these reduced equations. The effects of various associated parameters over the velocity and temperature profiles are plotted and the outcome of each associated parameter is discussed through graphs. The key findings are noted as follows: the velocity profile declines with an increase in the magnetic force number, and an increment in buoyancy parameter leads to the increase in the boundary layer thickness and decrease in the thickness of the thermal boundary layer.     

A comparative analysis of unsteady and steady Buongiorno's Williamson nanoliquid flow over a wedge with slip effects

Comparison between unsteady and steady MHD Buongiorno's model Williamson nanoliquid flow through a wedge with slip effects, chemical reaction and radiation is made in this analysis. Thermophoresis and Brownian motion are also considered in this study. Appropriate similarity variables are presented to transmute the governing PDEs into the set of non-linear ODEs. The most widely authenticated finite element method is implemented to analyze these set of ODEs numerically. The behavior of concentration, temperature and velocity sketches for varied values of relevant parameters is numerically calculated and the outcomes are plotted through graphs. The numerical values of dimensionless rates of mass transfer, heat and velocity are also evaluated and depicted through tables. It is noted that with upsurging values of angle of wedge parameter, the distributions of temperature of the liquid intensify in both steady and unsteady cases.