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2018 Volume 33 Issue 6
2018, 33(6): 1-10
doi: 10.3866/PKU.DXHX201712040
Abstract:
Nitrite is an indispensable part of the environment and the biological cycle, but excessive concentrations of nitrite not only pollute the environment, but also cause cancer. Therefore, it is of scientific and practical significance to realize efficient and rapid determination of nitrite. The analysis and determination of contaminants based on electrochemical sensing technology have become a research hotspot. In particular, the selection and design of working electrodes are very important for the researchers to improve the response speed, sensitivity, detection limit, reduce the cost and simplify the operation attention. For the detection of nitrite, this paper reviews the research progress of electrochemical sensors based on different electrodes including the glassy carbon electrode, carbon paste electrode, metal film, polymer film and carbon cloth electrode. Through the construction method and the comparison of electrocatalytic performance, the authors hope to provide a theoretical and practical guidance for the construction of new sensors.
Nitrite is an indispensable part of the environment and the biological cycle, but excessive concentrations of nitrite not only pollute the environment, but also cause cancer. Therefore, it is of scientific and practical significance to realize efficient and rapid determination of nitrite. The analysis and determination of contaminants based on electrochemical sensing technology have become a research hotspot. In particular, the selection and design of working electrodes are very important for the researchers to improve the response speed, sensitivity, detection limit, reduce the cost and simplify the operation attention. For the detection of nitrite, this paper reviews the research progress of electrochemical sensors based on different electrodes including the glassy carbon electrode, carbon paste electrode, metal film, polymer film and carbon cloth electrode. Through the construction method and the comparison of electrocatalytic performance, the authors hope to provide a theoretical and practical guidance for the construction of new sensors.
2018, 33(6): 11-17
doi: 10.3866/PKU.DXHX201801014
Abstract:
Aiming at improving graduate quality, we carried out a survey of students' training experience in chemistry teacher education. We further analyzed the underlying problems, which can be summarized as the absence of teacher education in different subjects, the long-term problem of subject barrier and management barrier, and the ignorance of student-centered education. We also made efforts to discuss these problems and to propose reform suggestions for future improvement.
Aiming at improving graduate quality, we carried out a survey of students' training experience in chemistry teacher education. We further analyzed the underlying problems, which can be summarized as the absence of teacher education in different subjects, the long-term problem of subject barrier and management barrier, and the ignorance of student-centered education. We also made efforts to discuss these problems and to propose reform suggestions for future improvement.
2018, 33(6): 18-20
doi: 10.3866/PKU.DXHX201801044
Abstract:
Some measures have been proposed to solve the problems found in structural model exercises. By establishing a VRML website, recording videos of model exercise teaching and encouraging students to have discussions with each other during the exercises, the teaching results of molecular and crystal structures have been improved effectively.
Some measures have been proposed to solve the problems found in structural model exercises. By establishing a VRML website, recording videos of model exercise teaching and encouraging students to have discussions with each other during the exercises, the teaching results of molecular and crystal structures have been improved effectively.
2018, 33(6): 21-25
doi: 10.3866/PKU.DXHX201802005
Abstract:
More and more attention is focused on the safety and security of the campus laboratory recently, but safety education is absent in undergraduate chemistry curriculum in most colleges and universities. Herein, the necessity of adding laboratory safety course into the undergraduates' curriculum was discussed from the perspective of humanism. The explorations on the chemical laboratory safety course for undergraduates were carried out by way of patterns, artifice, contents, and evaluation of teaching.
More and more attention is focused on the safety and security of the campus laboratory recently, but safety education is absent in undergraduate chemistry curriculum in most colleges and universities. Herein, the necessity of adding laboratory safety course into the undergraduates' curriculum was discussed from the perspective of humanism. The explorations on the chemical laboratory safety course for undergraduates were carried out by way of patterns, artifice, contents, and evaluation of teaching.
2018, 33(6): 26-32
doi: 10.3866/PKU.DXHX201712027
Abstract:
In this paper, the mechanism, influence factor and application examples for ortho lithiation reaction and lithium-halide exchange reaction of aromatic compounds were introduced. The similarities and differences between these two reaction are discussed, so that readers can well master and apply this two important synthesis methods.
In this paper, the mechanism, influence factor and application examples for ortho lithiation reaction and lithium-halide exchange reaction of aromatic compounds were introduced. The similarities and differences between these two reaction are discussed, so that readers can well master and apply this two important synthesis methods.
2018, 33(6): 33-37
doi: 10.3866/PKU.DXHX201801033
Abstract:
This paper recommended the experiment of "Determination of the content of dexamethasone acetate in mixed cream by high performance liquid chromatography", in this experiment several experimental skills such as weighing, hot water bath, vortex, ice bath, filtration, liquid transfer and other sample pretreatment skills are included, and UV spectrophotometer and HPLC are used, as well as the methods of quantitative measurement and data processing are requested to get. This experiment can fully promote the students' experimental skills, enhance the ability for practical application, and raise the preliminary scientific research thinking.
This paper recommended the experiment of "Determination of the content of dexamethasone acetate in mixed cream by high performance liquid chromatography", in this experiment several experimental skills such as weighing, hot water bath, vortex, ice bath, filtration, liquid transfer and other sample pretreatment skills are included, and UV spectrophotometer and HPLC are used, as well as the methods of quantitative measurement and data processing are requested to get. This experiment can fully promote the students' experimental skills, enhance the ability for practical application, and raise the preliminary scientific research thinking.
2018, 33(6): 38-44
doi: 10.3866/PKU.DXHX201712009
Abstract:
In this paper, a new chemical comprehensive experiment-synthesis of aniline tetramer and its application of electrochromic device, was developed. It includes the synthesis of aniline tetramer, the fabrication of electrochromic device and the measurement of the related properties. With the practice of this experiment, students can broaden their chemistry knowledge, improve their comprehensive experimental operation skills and professional qualities. In addition, students can have access to the frontier science and technology, which would greatly stimulate and cultivate their interest in scientific research.
In this paper, a new chemical comprehensive experiment-synthesis of aniline tetramer and its application of electrochromic device, was developed. It includes the synthesis of aniline tetramer, the fabrication of electrochromic device and the measurement of the related properties. With the practice of this experiment, students can broaden their chemistry knowledge, improve their comprehensive experimental operation skills and professional qualities. In addition, students can have access to the frontier science and technology, which would greatly stimulate and cultivate their interest in scientific research.
2018, 33(6): 45-47
doi: 10.3866/PKU.DXHX201801048
Abstract:
Based on the concept of student-centered and problem-oriented, the experimental content, experimental principle and phenomenon explanation on the change of direction of redox reaction induced by precipitation formation were discussed with the aim of guiding students to better understand and apply the Nernst equation.
Based on the concept of student-centered and problem-oriented, the experimental content, experimental principle and phenomenon explanation on the change of direction of redox reaction induced by precipitation formation were discussed with the aim of guiding students to better understand and apply the Nernst equation.
2018, 33(6): 48-52
doi: 10.3866/PKU.DXHX201801037
Abstract:
During the teaching process of 6s2 inert pair effect in the course of inorganic chemistry, three teaching principles, "theorization, intuition and regularity", have been proposed accordingly. By using these principles, students can understand and master the concept of 6s2 inertia pair effect in a relatively relax atmosphere. In addition, the gap between the widely spread knowledge points as well as the difficulty of learning and the understanding ability of the students is reduced successfully. Meanwhile, the use of these principles is very helpful to cultivate students' abilities of comprehensive induction, and finding and solving problems, which can make the students feel the importance of systematicness of knowledge, methodology of solving problems and the ability training.
During the teaching process of 6s2 inert pair effect in the course of inorganic chemistry, three teaching principles, "theorization, intuition and regularity", have been proposed accordingly. By using these principles, students can understand and master the concept of 6s2 inertia pair effect in a relatively relax atmosphere. In addition, the gap between the widely spread knowledge points as well as the difficulty of learning and the understanding ability of the students is reduced successfully. Meanwhile, the use of these principles is very helpful to cultivate students' abilities of comprehensive induction, and finding and solving problems, which can make the students feel the importance of systematicness of knowledge, methodology of solving problems and the ability training.
2018, 33(6): 53-59
doi: 10.3866/PKU.DXHX201712030
Abstract:
There is a variety of Marx's philosophic thinking in analytical chemistry experiment, such as laws of unity of opposites and mutual change of quality and quantity, etc. If tutors pay attention to analyzing problems from the perspective of dialectical materialism and infiltrate the philosophic thinking in daily teaching, it will help students to grasp scientific knowledge, to train scientific thinking, to foster Marx's philosophical view, and to improve the comprehensive quality. In the present paper, the authors make a tentative analysis of using Marx's philosophy principles in analytical chemistry laboratory teaching based on their teaching experience.
There is a variety of Marx's philosophic thinking in analytical chemistry experiment, such as laws of unity of opposites and mutual change of quality and quantity, etc. If tutors pay attention to analyzing problems from the perspective of dialectical materialism and infiltrate the philosophic thinking in daily teaching, it will help students to grasp scientific knowledge, to train scientific thinking, to foster Marx's philosophical view, and to improve the comprehensive quality. In the present paper, the authors make a tentative analysis of using Marx's philosophy principles in analytical chemistry laboratory teaching based on their teaching experience.
2018, 33(6): 60-64
doi: 10.3866/PKU.DXHX201801009
Abstract:
This paper will integrate the theoretical teaching with the laboratory teaching by modular constructing of the knowledge content. Because the core task of quantitative analytical chemistry is the analysis of quantity, it is divided into condition controlling and quantitative calculation. The condition control is the premise for the quantitative analysis. This part is divided into theoretical study and practical techniques. The ultimate goal of the quantitative analysis is to obtain the results. The quantitative calculation is divided into two parts, results calculation and evaluation. After modularization according to the function, the knowledge structure of analytical chemistry is made clear, and has vertical hierarchical and horizontal comparability, which will foster students' ability to make a summary of knowledge, analyze and solve problems. In such a way, students can not only grasp knowledge content, but also improve autonomous learning ability, and finally realize learning for life.
This paper will integrate the theoretical teaching with the laboratory teaching by modular constructing of the knowledge content. Because the core task of quantitative analytical chemistry is the analysis of quantity, it is divided into condition controlling and quantitative calculation. The condition control is the premise for the quantitative analysis. This part is divided into theoretical study and practical techniques. The ultimate goal of the quantitative analysis is to obtain the results. The quantitative calculation is divided into two parts, results calculation and evaluation. After modularization according to the function, the knowledge structure of analytical chemistry is made clear, and has vertical hierarchical and horizontal comparability, which will foster students' ability to make a summary of knowledge, analyze and solve problems. In such a way, students can not only grasp knowledge content, but also improve autonomous learning ability, and finally realize learning for life.
2018, 33(6): 65-70
doi: 10.3866/PKU.DXHX201712045
Abstract:
Comparing with integral and differential means, the half-life mean derived from nth order reaction to confirm reaction order is more reliable and universal. However, the derivation processes in textbooks are not clear. In this paper, we discussed the derivation processes of nth order reaction and its half-life in details using four different ways. It is beneficial for students to deepen the understanding of derivation processes about nth order reaction and its half-life.
Comparing with integral and differential means, the half-life mean derived from nth order reaction to confirm reaction order is more reliable and universal. However, the derivation processes in textbooks are not clear. In this paper, we discussed the derivation processes of nth order reaction and its half-life in details using four different ways. It is beneficial for students to deepen the understanding of derivation processes about nth order reaction and its half-life.
2018, 33(6): 71-76
doi: 10.3866/PKU.DXHX201801047
Abstract:
In order to reduce the educational difference and promote the international study in a convenient way, this article discussed the difference of undergraduate course system between Hebei University of Technology and City College of New York. By comparing their lecture system, we pointed out the problems for undergraduate students and proposed the distributed teaching method, which is efficient and needs to be applied to our educational system.
In order to reduce the educational difference and promote the international study in a convenient way, this article discussed the difference of undergraduate course system between Hebei University of Technology and City College of New York. By comparing their lecture system, we pointed out the problems for undergraduate students and proposed the distributed teaching method, which is efficient and needs to be applied to our educational system.
2018, 33(6): 77-90
doi: 10.3866/PKU.DXHX2017100041
Abstract:
The problems in the second International Metropolis Chemistry Olympiad were resolved, in which the test process, rules, and the problem solving skills as well as calculations were included.
The problems in the second International Metropolis Chemistry Olympiad were resolved, in which the test process, rules, and the problem solving skills as well as calculations were included.
