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2015 Volume 30 Issue 6
2015, 30(6): 1-6
doi: 10.3866/pku.DXHX20150601
Abstract:
DNA carries the genetic information for living organisms, but is challenged by both endogenous and exogenous stresses all the time. Chemical structures of DNA may be changed by these stresses and hence DNA damage can be produced. DNA damage may be cytotoxic or mutagenic when left unrepaired. Cells possess several pathways to repair DNA damage and maintain the stability of genome. The Nobel Prize in Chemistry 2015 was awarded jointly to Tomas Lindahl, Paul Modrich and Aziz Sancar "for mechanistic studies of DNA repair". Here we briefly describe the history of DNA repair research and its enormous influence to human health.
DNA carries the genetic information for living organisms, but is challenged by both endogenous and exogenous stresses all the time. Chemical structures of DNA may be changed by these stresses and hence DNA damage can be produced. DNA damage may be cytotoxic or mutagenic when left unrepaired. Cells possess several pathways to repair DNA damage and maintain the stability of genome. The Nobel Prize in Chemistry 2015 was awarded jointly to Tomas Lindahl, Paul Modrich and Aziz Sancar "for mechanistic studies of DNA repair". Here we briefly describe the history of DNA repair research and its enormous influence to human health.
2015, 30(6): 7-12
doi: 10.3866/pku.DXHX20150607
Abstract:
The flipped classroom method has been explored and applied to the University Organic Chemistry teaching using the network popular instant messaging software Tencent QQ group.
The flipped classroom method has been explored and applied to the University Organic Chemistry teaching using the network popular instant messaging software Tencent QQ group.
2015, 30(6): 13-16
doi: 10.3866/pku.DXHX20150613
Abstract:
The case-teaching method have been introduced into Flavors, Fragrances and Cosmetics General Educational Curriculum for about 5 years. It was proved that the case-teaching method not only aroused student's study enthusiasm, deepened their understanding of new knowledge, but also improved their abilities of analyzing and solving practical problems, and benefited teachers as well as students.
The case-teaching method have been introduced into Flavors, Fragrances and Cosmetics General Educational Curriculum for about 5 years. It was proved that the case-teaching method not only aroused student's study enthusiasm, deepened their understanding of new knowledge, but also improved their abilities of analyzing and solving practical problems, and benefited teachers as well as students.
2015, 30(6): 17-20
doi: 10.3866/pku.DXHX20150617
Abstract:
Background and development of the establishment of the association of University Chemistry and Chemical Engineering Experiment Teaching Center of Zhejiang Province(hereinafter as the "Association") and chemistry competition are introduced. Based on the "Association" and competition, the exchanging platform for laboratory teaching research and reform were established. The influence of the laboratory teaching demonstration center was expanded. At the same time, laboratory and course constructions as well as the training of talents were improved.
Background and development of the establishment of the association of University Chemistry and Chemical Engineering Experiment Teaching Center of Zhejiang Province(hereinafter as the "Association") and chemistry competition are introduced. Based on the "Association" and competition, the exchanging platform for laboratory teaching research and reform were established. The influence of the laboratory teaching demonstration center was expanded. At the same time, laboratory and course constructions as well as the training of talents were improved.
2015, 30(6): 21-24
doi: 10.3866/pku.DXHX20150621
Abstract:
In the teaching and management of the experimental curriculums of non-chemistry major undergraduates, including foundational inorganic chemistry and analytical chemistry, research efforts have been put on the teaching, training and cultivating of the teaching personnel, and the students' performance throughout the entire process in the experiment to the facilitate better innovation of the teaching practice.
In the teaching and management of the experimental curriculums of non-chemistry major undergraduates, including foundational inorganic chemistry and analytical chemistry, research efforts have been put on the teaching, training and cultivating of the teaching personnel, and the students' performance throughout the entire process in the experiment to the facilitate better innovation of the teaching practice.
2015, 30(6): 25-28
doi: 10.3866/pku.DXHX20150625
Abstract:
With the development of modern remote education, network course has become an important platform for imparting knowledge. The reform of teaching method in the network environment is the key to improve the quality of network education. This paper introduces teaching methods that embody the self-regulating learning idea.
With the development of modern remote education, network course has become an important platform for imparting knowledge. The reform of teaching method in the network environment is the key to improve the quality of network education. This paper introduces teaching methods that embody the self-regulating learning idea.
2015, 30(6): 29-31
doi: 10.3866/pku.DXHX20150629
Abstract:
In this paper, the importance for the teachers to conduct the experiment prior to the course was emphasized based on years of teaching on chemical analysis laboratory.
In this paper, the importance for the teachers to conduct the experiment prior to the course was emphasized based on years of teaching on chemical analysis laboratory.
2015, 30(6): 32-32
doi: 10.3866/pku.DXHX20150632
Abstract:
2015, 30(6): 33-44
doi: 10.3866/pku.DXHX20150633
Abstract:
This paper discusses the stability of the nitrogen molecule based on the chemical bond, and then introduces researches related to the nitrogen chemical bond activation from the industrial ammonia synthesis. The authors desire to explore a new approach for teaching elemental chemistry. The aim is to lead students to study and use the knowledge to learn the natural world, and improve the ability to analyze and solve problems.
This paper discusses the stability of the nitrogen molecule based on the chemical bond, and then introduces researches related to the nitrogen chemical bond activation from the industrial ammonia synthesis. The authors desire to explore a new approach for teaching elemental chemistry. The aim is to lead students to study and use the knowledge to learn the natural world, and improve the ability to analyze and solve problems.
2015, 30(6): 45-52
doi: 10.3866/pku.DXHX20150645
Abstract:
As a typical member of the zeolite family, zeolite A has been mentioned in inorganic chemistry, physical chemistry, and colloid chemistry. However,it often lose its charm in a class with so many students as well as in the ocean of knowledge. In the comprehensive experiment class for college seniors, exploring the effects of the alkalinity, temperature and time of crystallization in synthesizing zeolite has been added to guide the students to analyze and solve problems.
As a typical member of the zeolite family, zeolite A has been mentioned in inorganic chemistry, physical chemistry, and colloid chemistry. However,it often lose its charm in a class with so many students as well as in the ocean of knowledge. In the comprehensive experiment class for college seniors, exploring the effects of the alkalinity, temperature and time of crystallization in synthesizing zeolite has been added to guide the students to analyze and solve problems.
2015, 30(6): 53-56
doi: 10.3866/pku.DXHX20150653
Abstract:
Analysis of drinking water, including a few steps of measurements, is offered to the elective Chemical Experiments in Life course for non-chemistry majored undergraduates. The creative design, practice-based procedure was introduced to improve the scientific literacy of the undergraduates.
Analysis of drinking water, including a few steps of measurements, is offered to the elective Chemical Experiments in Life course for non-chemistry majored undergraduates. The creative design, practice-based procedure was introduced to improve the scientific literacy of the undergraduates.
2015, 30(6): 57-62
doi: 10.3866/pku.DXHX20150657
Abstract:
The preparation and characterization of chitosan was set up as a research-oriented comprehensive experiment in the course of Primary Training of Chemical Research in the summer semester of USTC. With the local lobster shell as the raw material, we inquired into the preparation of chitosan after a series of reactions such as deproteinization, desalination, decoloration and deacetylation. The physicochemical properties of chitosan were characterized by FT-IR, 1H-NMR, viscosity measurement and titrametry.
The preparation and characterization of chitosan was set up as a research-oriented comprehensive experiment in the course of Primary Training of Chemical Research in the summer semester of USTC. With the local lobster shell as the raw material, we inquired into the preparation of chitosan after a series of reactions such as deproteinization, desalination, decoloration and deacetylation. The physicochemical properties of chitosan were characterized by FT-IR, 1H-NMR, viscosity measurement and titrametry.
2015, 30(6): 63-66
doi: 10.3866/pku.DXHX20150663
Abstract:
To improve the catalyst activity measurements in the laboratory course, Raney-Cu and Ag/Raney-Cu, an Ag-modified Raney-Cu which was synthesized by the galvanic replacement method, were tested in the methanol decomposition reaction. Results showed that both Ag/Raney-Cu and Raney-Cu are more active than the conventional ZnO/Al2O3 catalyst for methanol decomposition at a large range of reaction temperatures, and Raney-Cu is more active at the lower temperature of 250℃. However, the catalytic activity of Ag/Raney-Cu increased remarkably with the increase of reaction temperature, and became more active than Raney-Cu at 350℃. This study suggests that both Raney-Cu and Ag/Raney-Cu are ideal low temperature catalysts for the catalytic activity measurements in the laboratory course.
To improve the catalyst activity measurements in the laboratory course, Raney-Cu and Ag/Raney-Cu, an Ag-modified Raney-Cu which was synthesized by the galvanic replacement method, were tested in the methanol decomposition reaction. Results showed that both Ag/Raney-Cu and Raney-Cu are more active than the conventional ZnO/Al2O3 catalyst for methanol decomposition at a large range of reaction temperatures, and Raney-Cu is more active at the lower temperature of 250℃. However, the catalytic activity of Ag/Raney-Cu increased remarkably with the increase of reaction temperature, and became more active than Raney-Cu at 350℃. This study suggests that both Raney-Cu and Ag/Raney-Cu are ideal low temperature catalysts for the catalytic activity measurements in the laboratory course.
2015, 30(6): 67-74
doi: 10.3866/pku.DXHX20150667
Abstract:
In this paper, a new comprehensive and design experiment of the physical chemistry laboratory was introduced. And the principle, apparatus setup and the experimental procedure were discussed in detail. The effects of the current density, time of electrolysis, the concentration of the supporting electrolyte, and other technical parameters on the cell voltage and the conversion rate of organic matter were explored. In addition, the teaching mode and practice of the experiment were introduced.
In this paper, a new comprehensive and design experiment of the physical chemistry laboratory was introduced. And the principle, apparatus setup and the experimental procedure were discussed in detail. The effects of the current density, time of electrolysis, the concentration of the supporting electrolyte, and other technical parameters on the cell voltage and the conversion rate of organic matter were explored. In addition, the teaching mode and practice of the experiment were introduced.
2015, 30(6): 75-78
doi: 10.3866/pku.DXHX20150675
Abstract:
By introducing the exceptions to the octet-rule, VSEPR theory and the related problems about octet-rule were discussed in the Structural Chemistry course, helping students understand the related theory and applications.
By introducing the exceptions to the octet-rule, VSEPR theory and the related problems about octet-rule were discussed in the Structural Chemistry course, helping students understand the related theory and applications.
2015, 30(6): 79-82
doi: 10.3866/pku.DXHX20150679
Abstract:
Discussion on the influences of the indicators in acid-base titration had been made based on theoretical calculations and experiments. The pH changes using general expression of acid-base titration were calculated when bromothymol blue and phenolphthalein were used as the indictors in the titration of HCl with NaOH. The results showed that too high or low concentration of the indicators did not help identify the end point. A proper concentration of indicator is the guarantee of sensitive color change, and thus the accuracy of the titration.
Discussion on the influences of the indicators in acid-base titration had been made based on theoretical calculations and experiments. The pH changes using general expression of acid-base titration were calculated when bromothymol blue and phenolphthalein were used as the indictors in the titration of HCl with NaOH. The results showed that too high or low concentration of the indicators did not help identify the end point. A proper concentration of indicator is the guarantee of sensitive color change, and thus the accuracy of the titration.
2015, 30(6): 83-88
doi: 10.3866/pku.DXHX20150683
Abstract:
Taking binomial distribution as an illustration, we elaborated the relationship between equilibrium distribution and the most probable distribution. According to the statistical mechanics, the binomial distribution approximates to the normal distribution when the number is large enough, and the relative fluctuation is inversely proportional to the square root of the number, we illustrated that the equilibrium distribution of a thermodynamic system could be described by the most probable distribution.
Taking binomial distribution as an illustration, we elaborated the relationship between equilibrium distribution and the most probable distribution. According to the statistical mechanics, the binomial distribution approximates to the normal distribution when the number is large enough, and the relative fluctuation is inversely proportional to the square root of the number, we illustrated that the equilibrium distribution of a thermodynamic system could be described by the most probable distribution.
