基于培养学生实践能力的分析化学实验教学方法研究

分析化学实验作为一门培养学生实践能力的课程,目前存在对学生基本操作训练不足、学生缺乏参与实验主动性、学生的数据处理和结果分析能力较差等问题。通过对障碍性实践教学法、任务型教学法、分析比较教学法等实验教学新方法的不断探索和尝试,解决教学中存在的问题,以达到培养学生综合实践能力的目标。     

素质培养在化工过程分析与合成课程教学中的实践

介绍了化工过程分析与合成课程教学实践和经验,通过对在高等院校化工类本科生教学采用了案例结合理论分析的启发式方法,阐述了教学过程中引导学生思考问题,指导学生研究问题,帮助学生解决问题的教学方法.教学实践显示,新教学模式对学生掌握基础知识,培养专业能力,提高素质具有较好的效果.     

通过本科创新实践活动提高学生综合素质和能力

本文通过在本科生培养过程中开展创新实践活动的教学实践,对创新实践活动的宗旨、选题及条件保障等方面问题进行了探讨.总结了创新实践活动对树立学生科研精神,培养学生科研意识,提升学生信息素养,提高毕业设计质量以及造就综合和应用型人才等方面的积极效果和意义.     

大学俄语写作的教学与实践

大学俄语写作教学是大学俄语教学中值得深入探讨的客观体现.作者结合多年的教学实践与经验阐述了如何在有限的时间内,分阶段对学生的俄语写作进行训练和培养,循序渐进地采取各种有效的教学措施,培养学生综合运用语言的能力.     

《化工原理课程设计》创新教学研究

论述了化工原理课程设计作为实践性教学环节的重要性，结合多年的教学实践，介绍了组织学生进行化工原理课程设计的具体思路和方法，通过这种方法的系统训练，较好的培养了学生的处理工程问题的能力。     

职业教育实践性教学的作用和特点

学生的技能是经过学习而逐步形成的,而实践是形成心智技能和动作技能的基本途径。实践教学担负着培养学生综合运用所学理论知识和实践技能去解决工作中实际问题的能力。实践教学是实现职业技术教育等人才培养目标的重要途径和手段。本文主要介绍实践性教学的作用、教学的特点及其教学的种类。     

工程训练中指导操作实训教学法的探索与研究

工程训练是培养学生创新精神、工程意识和操作技能的重要实践环节。工程训练的教学方法有很多种,其中指导操作实训法是工程训练教学过程中培养学生理论联系实际掌握操作技能、提高工程实践能力的基本方法。本文对指导操作实训法进行了深入的探讨和研究,为工程训练指导教师运用该法指导教学时提供了参考和借鉴,对学生操作技能、实践水平能力的提高起到了很大的促进作用。     

工程教育专业认证背景下化学工程与工艺专业学生实践能力培养研究

实践教学是工程教育专业认证中的重要内容,是学生创新能力培养的基本保障。通过对实践教学中实验课程教学、专业实习、双创训练、二课堂活动等进行改革,学生的实验技能、创新能力和解决化工实际问题的能力得到了提高。     

基于反应机理和案例教学的制药工艺学教学探索与实践

对目前变革中的制药工艺学教学中存在的问题进行了分析。结合该课程厚基础和强实践的特点,用反应机理培养学生解决工艺问题的思维方式,用案例教学培养学生综合解决问题的能力,改善了理论和实践教学模式和手段,对学生学习效果及能力培养等方面进行了有益的探索和实践。     

提高生化反应工程教学效果的探索

在生化反应工程教学中,我们重点讲授理论处理方法,培养科学思维方式;通过互动式教学提高学生学习的积极性和参与意识;补充介绍一些数值计算方法,克服学生对复杂数学问题的畏难情绪.     

Charge distributions and coagulation of radioactive aerosols

The self-charging of radioactive aerosols will be reduced by background ions, such as those produced by radioactive gases. The sources of these background ions and their production rates are specified for a reactor containment atmosphere during a possible nuclear accident. Previous theory is extended to calculate the charging of a polydisperse radioactive aerosol. Gaussian approximations to charge distributions on an aerosol of a given size, and are shown to give a good representation of the exact numerical charge distributions of a Cs aerosol at normal temperatures, and also for highly radioactive aerosol containing ¹³¹I in a containment atmosphere.

Extensive calculations are performed for charge-induced modifications to Brownian coagulation rates between steady-state size distributions of these radioactive aerosols, and also between small-sized radioactive aerosol and larger (non-radioactive) aerosol. The results show considerable enhancements of the coagulation rates between large and small-sized aerosol, but also a strong suppression of coagulation between large particles. Rate modifications calculated using the Gaussian approximations are generally close to the exact values. Time-dependent calculations for a monodisperse -decaying aerosol reveal enhancements in coagulation rates even when the average charge on the aerosol is positive. Our results are relevant to behaviour in a dusty plasma.     

Multiplicity and stability of oscillatory states in a continuous stirred tank reactor with exothermic consecutive reactions A → B → C

We study the dimensionless heat and mass balance equations describing a continuous stirred tank reactor in which there is occurring consecutive first order exothermic reactions. Analytical asymptotic calculations and numerical calculations are presented for both steady states and oscillatory states. A formal perturbation theory, via multitime scale techniques, is derived to account for limit cycles in phase space. The theory produces formulas which are immediately interpretable physically and from which the stability of the oscillations is immediately resolved without recourse to further techniques. Furthermore, numerical calculations via our theory are performed which are far cheaper and easier than a direct numerical search and computation involving the long time study of the basic differential equations.     

Resin Velocity and Temperature in Screw Processing

To analyze the effects of forces that affect the resin and its movement while it is processed in a screw, a simulation method is proposed based on finite element. The method includes mainly two series of equations and their numerical calculations. The movement equation of the resin in a screw represents the stress, the strain, and the relationship between velocity and stress of the cells. A discretized differential equation is used to express the exchange of shearing heat. Combined with the displacement and temperature boundary, the equations are solved by the numerical calculation procedure, and velocity and temperature distribution are worked out. The computation sample has illustrated the validity of the proposed method. And the results have shown its importance in an industrial application with aspects such as redesigning a screw or improving the quality of the plastic products.     

Collisional energy transfer in polyatomic molecules in the gas phase

This paper is an attempt to present an overall view of energy transfer between excited polyatomic molecules and polyatomic and monatomic bath, based on results obtained by classical trajectory calculations. It is not a general review of the subject but a summary based on work done by us in the last few years. We report average energies transferred in a collision and collisional energy transfer probability density functions for various collision partners as a function of various system parameters: temperature, vibrational and rotational energies of the hot and cold molecule, and relative translational energies. Various mechanisms for energy transfer are proposed, their dependence on the system parameters is explored, and the relevance of empirical numerical models to computational results is discussed.     

Prediction of flow–induced process variables based on similarity analysis in the liquid molding process

In general, a numerical scheme is a widely accepted technique for estimating resin flow in the liquid molding process. A numerical mold filling analysis is essential to optimize the manufacturing process of a composite. However, finding an optimal condition from the numerical analysis requires many numerical calculations. The efforts can be greatly reduced if a similarity solution replaces the repeated numerical calculations. In this study, similarity relations are proposed to predict the flow‐induced process variables. such as resin pressure, resin velocity, and flow front evolution time, during mold filling. Numerical simulations are performed for two cases where a material property, an injection condition or a part shape is different. The model is verified by applying the similarity relation for two numerical results obtained from the thin shell structure.     

Brände und Explosionen im Rahmen der Risikoermittlung

The procedure of assessing risks is treated by analyzing an event sequence following the puff release of gaseous propylene. The models for fireball, flash fire and explosion required for this purpose are presented. Their uncertainties and sensitivities are discussed and illustrated by numerical examples. Modeling and data uncertainties in assessing the probabilities of event sequences are characterized; their mathematical treatment is shown. Deterministic as well as probabilistic calculations are performed and their results are compared.     

Concepts for the Simulation of Wall‐Catalyzed Reactions in Microchannel Reactors with Mesopores in the Wall Region

The realization of reactions in microchannel reactors demands apart from optimal process conditions also a useful geometric layout of the apparatus. Information about the usefulness of the geometry is available through the simulation of the concentrations and the temperature field and their evaluation. Although the mesopores used in microchannel reactors are very regular, the discrepancies between channel and pore dimensions are very large and so, a simultaneous numerical calculation of the entire reactor is neither meaningful nor possible. Therefore, in this paper, an effective kinetics for isothermal reactions considering the diffusional mass flow through the pore mouth is introduced. Still, numerical calculations are very expensive and have the disadvantage that the influence of the individual parameters is seen only by a lot of calculations with changed parameters. That's why a survey of cases with analytical solutions and with other concepts (using mass transfer coefficients, effectiveness factors, etc.) is given, too.     

THE EXACT PENETRATION MODEL OF DIFFUSION IN MULTICOMPONENT IDEAL GAS MIXTURES. ANALYTICAL AND NUMERICAL SOLUTIONS

An exact analytical solution is derived for the penetration model of diffusion in multicomponent ideal gas mixtures at constant pressure and temperature. It takes the form of a matrizant solution to the continuity and Maxwell-Stefan equations transformed by introduction of a similarity variable, and includes as special cases the corresponding binary and linearized theory solutions

Direct numerical implementation of the analytical solution is computationally inefficient, but an alternative finite-difference algorithm is developed in which the transformed equations are solved by Euler's method with a simple shooting technique. Sample calculations are reported for two ternary diffusion problems

It is concluded on the basis of the theoretical and numerical results that the linearized theory predictions should provide an excellent approximation to the exact solution of the penetration model.     

THE EXACT PENETRATION MODEL OF DIFFUSION IN MULTICOMPONENT IDEAL GAS MIXTURES. ANALYTICAL AND NUMERICAL SOLUTIONS

An exact analytical solution is derived for the penetration model of diffusion in multicomponent ideal gas mixtures at constant pressure and temperature. It takes the form of a matrizant solution to the continuity and Maxwell-Stefan equations transformed by introduction of a similarity variable, and includes as special cases the corresponding binary and linearized theory solutions

Direct numerical implementation of the analytical solution is computationally inefficient, but an alternative finite-difference algorithm is developed in which the transformed equations are solved by Euler's method with a simple shooting technique. Sample calculations are reported for two ternary diffusion problems

It is concluded on the basis of the theoretical and numerical results that the linearized theory predictions should provide an excellent approximation to the exact solution of the penetration model.     

Lagrangian particle calculations of distributive mixing: Limitations and applications

A popular computational scheme to assess distributive mixing is to advect Lagrangian particles from one or more small initial clusters, divide the mixing domain into bins, and count the number of particles in each bin. Either the variance among bin counts, or an entropy associated with the bin counts, measures the progress of mixing. We analyze the numerical and physical limitations of such measures, and examines their behavior in chaotic laminar mixing flows. In a time-periodic flow each mixing measure reaches a limiting value, which is either controlled by the number of Lagrangian particles and the number of bins (a numerical limit), or by the presence of islands in the flow (a physical limit). We provide analytical expressions for both limits. The same statistical concepts are used to analyze Poincaré sections of chaotic flows, resulting in a calculation that will detect all islands that cover one or more bins. This provides a way to search for protocols that are highly chaotic (i.e., contain very small islands), and are thus very effective at mixing. These concepts are applied in sample calculations of the sine flow. The T=1.6 sine flow, known to be highly chaotic, has small but easily detected islands. Among highly chaotic flows, the location of the initial cluster of Lagrangian particles is as important to the rate of distributive mixing as the choice of flow protocol.