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2017 Volume 32 Issue 7
2017, 32(7): 1-7
doi: 10.3866/PKU.DXHX201703031
Abstract:
As an electrical counterpart to ferromagnets,ferroelectrics are featured by macroscopic spontaneous polarizations which are evidenced by electrical hysteresis loops.Ferroelectrics have been widely used in many fields such as information storage,energy transformation,switching and sensing.Molecule-based ferroelectrics have their advantages over conventional inorganic ferroelectric ceramics and could be used as a complement or an alternative to inorganic ones in many situations.In this paper,we briefly introduced the concept,principle and characteristics of ferroelectrics and summarized the development of molecule-based ferroelectrics.
As an electrical counterpart to ferromagnets,ferroelectrics are featured by macroscopic spontaneous polarizations which are evidenced by electrical hysteresis loops.Ferroelectrics have been widely used in many fields such as information storage,energy transformation,switching and sensing.Molecule-based ferroelectrics have their advantages over conventional inorganic ferroelectric ceramics and could be used as a complement or an alternative to inorganic ones in many situations.In this paper,we briefly introduced the concept,principle and characteristics of ferroelectrics and summarized the development of molecule-based ferroelectrics.
2017, 32(7): 8-11
doi: 10.3866/PKU.DXHX201702019
Abstract:
Practice of small-class teaching in structural chemistry is briefly introduced.Practice of several years demonstrated that small-class teaching was effective to consolidate the foundation of the students and broaden their horizons,the communication between students and teachers was also greatly promoted.We believe that the quality of teaching will be raised.
Practice of small-class teaching in structural chemistry is briefly introduced.Practice of several years demonstrated that small-class teaching was effective to consolidate the foundation of the students and broaden their horizons,the communication between students and teachers was also greatly promoted.We believe that the quality of teaching will be raised.
2017, 32(7): 12-17
doi: 10.3866/PKU.DXHX201612029
Abstract:
The work of graduate teaching assistants can train and cultivate the graduate students' abilities in many aspects,and it is also the supplement to the undergraduate teaching resources.We need to strengthen the training,guidance,management and evaluation of the graduate teaching assistants,to improve the unified management of laboratory teaching and to enhance the supervision and guidance of students' learning.This paper describes the experiences of graduate teaching assistants and also provides some reflections and suggestions for laboratory teaching management and training of graduate teaching assistants in the future.
The work of graduate teaching assistants can train and cultivate the graduate students' abilities in many aspects,and it is also the supplement to the undergraduate teaching resources.We need to strengthen the training,guidance,management and evaluation of the graduate teaching assistants,to improve the unified management of laboratory teaching and to enhance the supervision and guidance of students' learning.This paper describes the experiences of graduate teaching assistants and also provides some reflections and suggestions for laboratory teaching management and training of graduate teaching assistants in the future.
2017, 32(7): 18-22
doi: 10.3866/PKU.DXHX201612025
Abstract:
A virtual experiment "properties and identification of inorganic compounds" was developed in order to solve the problems existing in the laboratory teaching of inorganic qualitative analysis.The virtual experiment was provided simultaneously with the lab experiments so as to train the students' ability of qualitative analysis systematically.
A virtual experiment "properties and identification of inorganic compounds" was developed in order to solve the problems existing in the laboratory teaching of inorganic qualitative analysis.The virtual experiment was provided simultaneously with the lab experiments so as to train the students' ability of qualitative analysis systematically.
2017, 32(7): 23-27
doi: 10.3866/PKU.DXHX201701002
Abstract:
Synthetic methodology has been introduced to organic chemistry laboratory course by taking the preparation of ethyl benzoate as an example.The experiments for each student were carried out by drawing lots,and the reaction conditions such as heating sources (electricity or microwave power),solvents (toluene or cyclohexane) and reaction time were investigated by the undergraduate students.Additionally,the critical review of chemical literatures was added into the teaching and the experiment results were discussed in order to improve the innovative thinking and scientific research ability of the undergraduate students.
Synthetic methodology has been introduced to organic chemistry laboratory course by taking the preparation of ethyl benzoate as an example.The experiments for each student were carried out by drawing lots,and the reaction conditions such as heating sources (electricity or microwave power),solvents (toluene or cyclohexane) and reaction time were investigated by the undergraduate students.Additionally,the critical review of chemical literatures was added into the teaching and the experiment results were discussed in order to improve the innovative thinking and scientific research ability of the undergraduate students.
2017, 32(7): 28-32
doi: 10.3866/PKU.DXHX201612026
Abstract:
The application of inquiry and research type teaching mode in instrumental analysis laboratory teaching was explored.Through exploring the new teaching mode,we inspire students and improve their research and cooperation skills to achieve the goal of enhancing the quality of the laboratory teaching.
The application of inquiry and research type teaching mode in instrumental analysis laboratory teaching was explored.Through exploring the new teaching mode,we inspire students and improve their research and cooperation skills to achieve the goal of enhancing the quality of the laboratory teaching.
2017, 32(7): 33-36
doi: 10.3866/PKU.DXHX201701020
Abstract:
This paper introduces the recent practice of teaching experimental design in physical chemistry laboratory in the Chemical Experimental Teaching Center of Nanjing University.The design of experiment is organized in four parts:selecting main instruments,submitting a preliminary proposal,making a presentation of the detailed project,and carrying out the designed experiment.The teaching practice proves that it is an effective route to cultivate the comprehensive quality and the independent innovation ability of students.
This paper introduces the recent practice of teaching experimental design in physical chemistry laboratory in the Chemical Experimental Teaching Center of Nanjing University.The design of experiment is organized in four parts:selecting main instruments,submitting a preliminary proposal,making a presentation of the detailed project,and carrying out the designed experiment.The teaching practice proves that it is an effective route to cultivate the comprehensive quality and the independent innovation ability of students.
2017, 32(7): 37-43
doi: 10.3866/PKU.DXHX201701006
Abstract:
This paper put forward a new design for information instruction teaching,based on the concept and characteristics of information instruction.Taking the determination of COD in water as an example,the complete instructional design scheme was constructed and implemented according to the new teaching model.The application of the new model was discussed,and the influence of information technology on the curriculum teaching was analyzed.The results suggested an improved master of the experiment and a shortened experimental time of the experimental implementation with the new teaching mode.
This paper put forward a new design for information instruction teaching,based on the concept and characteristics of information instruction.Taking the determination of COD in water as an example,the complete instructional design scheme was constructed and implemented according to the new teaching model.The application of the new model was discussed,and the influence of information technology on the curriculum teaching was analyzed.The results suggested an improved master of the experiment and a shortened experimental time of the experimental implementation with the new teaching mode.
2017, 32(7): 44-47
doi: 10.3866/PKU.DXHX201701011
Abstract:
The research-oriented teaching mode was introduced to the course of chemistry experiment and scientific research method and the"classroom learning-independent experiment-scientific guidance"teaching system was constructed and applied.The research-oriented experiments were designed including literature investigation,experiment design,experiment implementation,and results analysis process.A diversified assessment system was also established to stimulate students' enthusiasm for scientific research and consciousness for innovation.
The research-oriented teaching mode was introduced to the course of chemistry experiment and scientific research method and the"classroom learning-independent experiment-scientific guidance"teaching system was constructed and applied.The research-oriented experiments were designed including literature investigation,experiment design,experiment implementation,and results analysis process.A diversified assessment system was also established to stimulate students' enthusiasm for scientific research and consciousness for innovation.
2017, 32(7): 48-53
doi: 10.3866/PKU.DXHX201701013
Abstract:
With the innovation and entrepreneurship education reform in the higher education,the approaches to enhance students' innovation ability and autonomous learning ability in the theoretical teaching of chemical engineering principles of bio-engineering specialty are discussed in this article,including how to change the carrier of teaching contents,improve the teaching methods and carry out the multidimensional assessment.
With the innovation and entrepreneurship education reform in the higher education,the approaches to enhance students' innovation ability and autonomous learning ability in the theoretical teaching of chemical engineering principles of bio-engineering specialty are discussed in this article,including how to change the carrier of teaching contents,improve the teaching methods and carry out the multidimensional assessment.
2017, 32(7): 54-59
doi: 10.3866/PKU.DXHX201702017
Abstract:
The discussion on the stability of different carbocations is one of the key topics in the teaching of organic chemistry at university.However,the results in one text or document often disagreed with those of the others.In this paper,we present the reasonable comparison and explanation about the different kinds of carbocations based on the comprehensive analysis of references,data and theory.
The discussion on the stability of different carbocations is one of the key topics in the teaching of organic chemistry at university.However,the results in one text or document often disagreed with those of the others.In this paper,we present the reasonable comparison and explanation about the different kinds of carbocations based on the comprehensive analysis of references,data and theory.
2017, 32(7): 60-67
doi: 10.3866/PKU.DXHX201612017
Abstract:
Using the home-made adsorption device,a method for quick measurement of solid specific surface area was established based on the BET adsorption theory.A contrast experiment designed by multipoint method was also carried out with the automatic adsorption apparatus.The experimental results show that the presented method is convenient.We hope that peers who devote in physical chemistry laboratory teaching can use this characteristic experiment.
Using the home-made adsorption device,a method for quick measurement of solid specific surface area was established based on the BET adsorption theory.A contrast experiment designed by multipoint method was also carried out with the automatic adsorption apparatus.The experimental results show that the presented method is convenient.We hope that peers who devote in physical chemistry laboratory teaching can use this characteristic experiment.
2017, 32(7): 68-71
doi: 10.3866/PKU.DXHX201701022
Abstract:
Chemical biology is one cutting-edge interdisciplinary subject,which utilizes chemical tools or compounds to answer biological questions.In this paper,we mainly introduce the laboratory course platform of the chemical biology laboratory course,which is designed for top-notch chemistry-majored students in Tsinghua University,including its curriculum implementation,teaching experience and safety management.
Chemical biology is one cutting-edge interdisciplinary subject,which utilizes chemical tools or compounds to answer biological questions.In this paper,we mainly introduce the laboratory course platform of the chemical biology laboratory course,which is designed for top-notch chemistry-majored students in Tsinghua University,including its curriculum implementation,teaching experience and safety management.
2017, 32(7): 72-76
doi: 10.3866/PKU.DXHX201701018
Abstract:
The entire chemical history is about a history that scientists devote themselves to science and consciously or unconsciously practice materialist and dialectics.Therefore,rich material can be found in chemistry for moral and scientific methodology education.Chemistry teachers should take opportunities to conduct moral education,including Marxist dialectical view of nature,patriotism,volition and character,scientific spirits of seeking truth from facts for promotion of the quality of teaching and learning.
The entire chemical history is about a history that scientists devote themselves to science and consciously or unconsciously practice materialist and dialectics.Therefore,rich material can be found in chemistry for moral and scientific methodology education.Chemistry teachers should take opportunities to conduct moral education,including Marxist dialectical view of nature,patriotism,volition and character,scientific spirits of seeking truth from facts for promotion of the quality of teaching and learning.
2017, 32(7): 77-82
doi: 10.3866/PKU.DXHX201612035
Abstract:
In this paper,the quantitative relationship between the bond energy,bond length,the acidity of the H-C bond and the electronegativity of valence orbital of carbon atom were studied.The research shows that the bond energies of X-C bonds increase linearly with the increase of the electronegativity of valence orbital of carbon atom;the bond lengths of H-C and C-C bonds decrease linearly with the increase of the electronegativity of valence orbital of carbon atom;the acidities of H-C bonds increase linearly with the increase of the electronegativity of valence orbital of carbon atom.Therefore,whether the experimental result of property of a chemical bond is correct or not can be judged by means of plotting the experimental result versus the electronegativity of valence orbital of carbon atom for these organic compounds with similar molecule structure.
In this paper,the quantitative relationship between the bond energy,bond length,the acidity of the H-C bond and the electronegativity of valence orbital of carbon atom were studied.The research shows that the bond energies of X-C bonds increase linearly with the increase of the electronegativity of valence orbital of carbon atom;the bond lengths of H-C and C-C bonds decrease linearly with the increase of the electronegativity of valence orbital of carbon atom;the acidities of H-C bonds increase linearly with the increase of the electronegativity of valence orbital of carbon atom.Therefore,whether the experimental result of property of a chemical bond is correct or not can be judged by means of plotting the experimental result versus the electronegativity of valence orbital of carbon atom for these organic compounds with similar molecule structure.
2017, 32(7): 83-87
doi: 10.3866/PKU.DXHX201612036
Abstract:
Physical chemistry course is one of the basic theories of chemical science and chemical technology.The main contents of physical chemistry include two parts,the basic theories and scientific methods.The Taylor series expansion is one of the commonly used mathematical formulas.It is useful when dealing with complex problems.In this paper,the Taylor series expansion is introduced in the derivation of the Clapeyron equation,the freezing-point depression formula and the Kelvin formula.The basic idea of using Taylor series expansion to obtain the relationship between thermodynamic functions is summarized.This work provides a reference for the use of Taylor series expansion in physical chemistry.
Physical chemistry course is one of the basic theories of chemical science and chemical technology.The main contents of physical chemistry include two parts,the basic theories and scientific methods.The Taylor series expansion is one of the commonly used mathematical formulas.It is useful when dealing with complex problems.In this paper,the Taylor series expansion is introduced in the derivation of the Clapeyron equation,the freezing-point depression formula and the Kelvin formula.The basic idea of using Taylor series expansion to obtain the relationship between thermodynamic functions is summarized.This work provides a reference for the use of Taylor series expansion in physical chemistry.
2017, 32(7): 88-92
doi: 10.3866/PKU.DXHX201701001
Abstract:
The buffer,composed of 6 weak acids with the different pKa(citric acid,phosphoric acid,boric acid,hydrazine,dimethylamine cation and diethylamine cation),can work well in the pH range of 2-12.By manipulating the combination of the concentrations of the weak acids,a constant buffer capacity of 0.7C average can be obtained in the entire pH range.All the precise calculations and plottings were conducted via the Sigmaplot software.
The buffer,composed of 6 weak acids with the different pKa(citric acid,phosphoric acid,boric acid,hydrazine,dimethylamine cation and diethylamine cation),can work well in the pH range of 2-12.By manipulating the combination of the concentrations of the weak acids,a constant buffer capacity of 0.7C average can be obtained in the entire pH range.All the precise calculations and plottings were conducted via the Sigmaplot software.
