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2020 Volume 35 Issue 2
2020, 35(2): 1-5
doi: 10.3866/PKU.DXHX201905073
Abstract:
This paper introduces the reform measures on the general chemistry principle laboratory, which is provided for the science-majored students by the chemistry laboratory center of Xi'an Jiaotong University after the admissions by categories. The reform involves many aspects, including reforming the laboratory teaching system, adopting the hybrid teaching method, blending in the course ideological element and strengthening the process evaluation, etc. These measures correspondingly enhanced the cultivation to the students' awareness of environmental, active exploration, scientific thinking and practical and realistic scientism. The acquired results were also presented.
This paper introduces the reform measures on the general chemistry principle laboratory, which is provided for the science-majored students by the chemistry laboratory center of Xi'an Jiaotong University after the admissions by categories. The reform involves many aspects, including reforming the laboratory teaching system, adopting the hybrid teaching method, blending in the course ideological element and strengthening the process evaluation, etc. These measures correspondingly enhanced the cultivation to the students' awareness of environmental, active exploration, scientific thinking and practical and realistic scientism. The acquired results were also presented.
2020, 35(2): 6-9
doi: 10.3866/PKU.DXHX201905050
Abstract:
The National Chemical Experiment Teaching Center of Nanjing University reformed the chemistry laboratory teaching based on the "3-to-3" undergraduate talents cultivation mode put forward by Nanjing University. The "academic talent training" laboratory course was reformed, the academic-orientated laboratory course was strengthened, and the "employment talent training" laboratory course was constructed. During the past 10 years, great progress has been made based on these reforms.
The National Chemical Experiment Teaching Center of Nanjing University reformed the chemistry laboratory teaching based on the "3-to-3" undergraduate talents cultivation mode put forward by Nanjing University. The "academic talent training" laboratory course was reformed, the academic-orientated laboratory course was strengthened, and the "employment talent training" laboratory course was constructed. During the past 10 years, great progress has been made based on these reforms.
2020, 35(2): 10-13
doi: 10.3866/PKU.DXHX201906012
Abstract:
This paper introduces the blended teaching practice of flipped classroom based on online course in college chemistry in Tianjin University since 2017, including the organization mode of teaching process, the selection of flipped leaning content, the proportion of flipped learning time in total class hours, the final test scores analysis and teaching reflection. In this study, flipped class hours accounted for 30%-50% of the total class hours and teaching content in which students had already accumulated some basic knowledge during middle school were selected in flipped classroom. The result showed that the teaching effect of flipped classroom was superior to that of traditional parallel class.
This paper introduces the blended teaching practice of flipped classroom based on online course in college chemistry in Tianjin University since 2017, including the organization mode of teaching process, the selection of flipped leaning content, the proportion of flipped learning time in total class hours, the final test scores analysis and teaching reflection. In this study, flipped class hours accounted for 30%-50% of the total class hours and teaching content in which students had already accumulated some basic knowledge during middle school were selected in flipped classroom. The result showed that the teaching effect of flipped classroom was superior to that of traditional parallel class.
2020, 35(2): 14-20
doi: 10.3866/PKU.DXHX201906014
Abstract:
The content of elemental chemistry is diversified, the regularity is not easy to be seen, and the traditional teaching methods are boring. These factors have affected students' interest in learning. In order to solve these problems, based on years of teaching experiences, the authors explore elemental chemistry teaching methods from the aspects of optimizing teaching content and teaching methods.
The content of elemental chemistry is diversified, the regularity is not easy to be seen, and the traditional teaching methods are boring. These factors have affected students' interest in learning. In order to solve these problems, based on years of teaching experiences, the authors explore elemental chemistry teaching methods from the aspects of optimizing teaching content and teaching methods.
2020, 35(2): 21-26
doi: 10.3866/PKU.DXHX201906045
Abstract:
In response to the problems existing in the traditional English for chemistry teaching, a new mode is proposed merging task-based method with rain classroom. The characteristics of the integration of task orientation with rain classroom are analyzed and the teaching procedure, methods and effects in the course are described. Questionnaire survey and qualitative comparison are used to examine the effect of this teaching mode. The results show that the teaching mode can significantly improve the classroom atmosphere, teacher-student interaction and student participation; the integration of rain classroom can significantly improve the effect of task-based teaching; rain classroom can improve the daily teaching management to a certain extent; and the teaching mode can improve students' interest as well as academic performance.
In response to the problems existing in the traditional English for chemistry teaching, a new mode is proposed merging task-based method with rain classroom. The characteristics of the integration of task orientation with rain classroom are analyzed and the teaching procedure, methods and effects in the course are described. Questionnaire survey and qualitative comparison are used to examine the effect of this teaching mode. The results show that the teaching mode can significantly improve the classroom atmosphere, teacher-student interaction and student participation; the integration of rain classroom can significantly improve the effect of task-based teaching; rain classroom can improve the daily teaching management to a certain extent; and the teaching mode can improve students' interest as well as academic performance.
2020, 35(2): 27-32
doi: 10.3866/PKU.DXHX201906035
Abstract:
Instrumental analysis laboratory is one of the important courses in chemistry and related profession. Combining with the course characteristic and training objective, comparative teaching method has been brought into the classroom teaching. The meaning and function of the comparative teaching method have been pointed out. The practice and application of comparing in laboratory teaching have been introduced. The method has enhanced students' knowledge to all kinds of instruments functions and the features stimulated students' interest in experiment and the innovation spirit. Their cognitive abilities have been continuously built, enriched, improved and developed in the process of comparing. Good teaching results have been achieved.
Instrumental analysis laboratory is one of the important courses in chemistry and related profession. Combining with the course characteristic and training objective, comparative teaching method has been brought into the classroom teaching. The meaning and function of the comparative teaching method have been pointed out. The practice and application of comparing in laboratory teaching have been introduced. The method has enhanced students' knowledge to all kinds of instruments functions and the features stimulated students' interest in experiment and the innovation spirit. Their cognitive abilities have been continuously built, enriched, improved and developed in the process of comparing. Good teaching results have been achieved.
2020, 35(2): 33-42
doi: 10.3866/PKU.DXHX201905052
Abstract:
A comprehensive exploratory experiment, preparation of calcium alginate microcapsules and nano-Fe3O4 is introduced to explore the effect of adsorbing organic matter and metal ions in water. This experiment is in line with the cutting-edge science development, which can fully stimulate students' interest in learning, and change passive learning into active learning. It is very conducive to improving students' comprehensive inquiry ability.
A comprehensive exploratory experiment, preparation of calcium alginate microcapsules and nano-Fe3O4 is introduced to explore the effect of adsorbing organic matter and metal ions in water. This experiment is in line with the cutting-edge science development, which can fully stimulate students' interest in learning, and change passive learning into active learning. It is very conducive to improving students' comprehensive inquiry ability.
2020, 35(2): 43-45
doi: 10.3866/PKU.DXHX201905048
Abstract:
The methodic error of reaction between acetone and iodine was investigated using a simple and novel method. The relative error was calculated to as low as 10-4. We also give a discussion on the reason causing this error.
The methodic error of reaction between acetone and iodine was investigated using a simple and novel method. The relative error was calculated to as low as 10-4. We also give a discussion on the reason causing this error.
2020, 35(2): 46-49
doi: 10.3866/PKU.DXHX201906028
Abstract:
The "comprehensive utilization of ilmenite" experiment in the comprehensive chemistry laboratory is divided into several modules and thus more experimental contents can be extended. The modules can be freely selected according to different specialties, different teaching levels and different lab time, so as to serve the teaching purposes.
The "comprehensive utilization of ilmenite" experiment in the comprehensive chemistry laboratory is divided into several modules and thus more experimental contents can be extended. The modules can be freely selected according to different specialties, different teaching levels and different lab time, so as to serve the teaching purposes.
2020, 35(2): 50-57
doi: 10.3866/PKU.DXHX201905084
Abstract:
An experiment "Doping and Photocatalytic Performance of TiO2 Nanopowder" was performed in inorganic comprehensive laboratory for Boling Class of Nankai University. After the dopant precursors and corresponding contents were determined by the students, different elements doped TiO2 powders were prepared by sol-gel method, and characterized by scanning electronic microscopy, transmittance electronic microscopy, powder X-ray diffraction and UV-Vis diffuse reflectance spectroscopy. The photocatalytic performances of the prepared catalysts were monitored by the degradation of methyl orange as the simulated wastewater to select the superior ones for photocatalytic water splitting test. Through this comprehensive experiment related to research frontier, the students in Boling Class can obtain basic research training and their scientific literacy can be improved.
An experiment "Doping and Photocatalytic Performance of TiO2 Nanopowder" was performed in inorganic comprehensive laboratory for Boling Class of Nankai University. After the dopant precursors and corresponding contents were determined by the students, different elements doped TiO2 powders were prepared by sol-gel method, and characterized by scanning electronic microscopy, transmittance electronic microscopy, powder X-ray diffraction and UV-Vis diffuse reflectance spectroscopy. The photocatalytic performances of the prepared catalysts were monitored by the degradation of methyl orange as the simulated wastewater to select the superior ones for photocatalytic water splitting test. Through this comprehensive experiment related to research frontier, the students in Boling Class can obtain basic research training and their scientific literacy can be improved.
2020, 35(2): 58-63
doi: 10.3866/PKU.DXHX201906017
Abstract:
In the magnetic susceptibility measurement experiment, the traditional method is to use the Gouy magnetic balance, an instrument which is cumbersome and complicated to operate. This paper provides a new type of benchtop magnetic balance for the determination of the magnetic susceptibility of complexes. The basic principle, method, operation steps and data analysis of this magnetic balance are introduced by measuring the magnetic susceptibility of three commonly used complexes. By comparing the measured values with standards, it is apparent that this portable instrument has smaller measurement error and higher precision, which is suitable for experimental teaching and scientific research.
In the magnetic susceptibility measurement experiment, the traditional method is to use the Gouy magnetic balance, an instrument which is cumbersome and complicated to operate. This paper provides a new type of benchtop magnetic balance for the determination of the magnetic susceptibility of complexes. The basic principle, method, operation steps and data analysis of this magnetic balance are introduced by measuring the magnetic susceptibility of three commonly used complexes. By comparing the measured values with standards, it is apparent that this portable instrument has smaller measurement error and higher precision, which is suitable for experimental teaching and scientific research.
2020, 35(2): 64-69
doi: 10.3866/PKU.DXHX201906046
Abstract:
An instrumental analysis experiment "Diversified assembly and application of optic fiber spectrometer" is recommended for undergraduates. UV-Vis spectrometer, molecular fluorescence spectrometer, near-infrared spectrometer, Raman spectrometer, and laser-induced fluorescence spectrometer can be assembled using light source, fiber, and charge-coupled devices detector, etc. Through the practice of this experiment, the traditional optical experiment is extended. It is helpful for students to cultivate the professional skills and abilities comprehensively by hands-on assembling the optical instruments.
An instrumental analysis experiment "Diversified assembly and application of optic fiber spectrometer" is recommended for undergraduates. UV-Vis spectrometer, molecular fluorescence spectrometer, near-infrared spectrometer, Raman spectrometer, and laser-induced fluorescence spectrometer can be assembled using light source, fiber, and charge-coupled devices detector, etc. Through the practice of this experiment, the traditional optical experiment is extended. It is helpful for students to cultivate the professional skills and abilities comprehensively by hands-on assembling the optical instruments.
2020, 35(2): 70-74
doi: 10.3866/PKU.DXHX201906008
Abstract:
In this paper, a new experiment named "synthesis and characterization of a fluorescent molecule based on Schiff-base" is introduced. It contains the synthesis and characterization of organic compounds, the determination of fluorescence, and the detection of metal ions. This experiment is helpful for students to better understand inorganic chemistry, organic chemistry and analytical chemistry. Moreover, it gives students an opportunity to know the study of organic fluorescent probes. This will stimulate students' interest in scientific research and cultivate their research ability. Thus, this experiment can be introduced to senior undergraduates.
In this paper, a new experiment named "synthesis and characterization of a fluorescent molecule based on Schiff-base" is introduced. It contains the synthesis and characterization of organic compounds, the determination of fluorescence, and the detection of metal ions. This experiment is helpful for students to better understand inorganic chemistry, organic chemistry and analytical chemistry. Moreover, it gives students an opportunity to know the study of organic fluorescent probes. This will stimulate students' interest in scientific research and cultivate their research ability. Thus, this experiment can be introduced to senior undergraduates.
2020, 35(2): 75-81
doi: 10.3866/PKU.DXHX201911038
Abstract:
Peking University, striving to be a top university in world, has made rapid progress in research and teaching, resulting in the subsequent increase in the production of hazardous waste in laboratories. How to ensure the safety and temporary storage of these hazardous wastes during campus hours has become an important part of the laboratory safety management and environmental protection work. We manage the hazardous waste by classification according to its different natures. We have also optimized the structure of the cabinet for temporary storage of hazardous chemical waste. The VOCs volatilized in the temporary storage environment were monitored, and the purification test of the polluted gas was carried out by using the titanium dioxide nanowire photocatalyst. It was found that all detected pollutants could be degraded by the catalyst, which showed that photocatalytic technology is a promising method used to solve the complex VOCs pollution problem in campus hazardous waste temporary storage.
Peking University, striving to be a top university in world, has made rapid progress in research and teaching, resulting in the subsequent increase in the production of hazardous waste in laboratories. How to ensure the safety and temporary storage of these hazardous wastes during campus hours has become an important part of the laboratory safety management and environmental protection work. We manage the hazardous waste by classification according to its different natures. We have also optimized the structure of the cabinet for temporary storage of hazardous chemical waste. The VOCs volatilized in the temporary storage environment were monitored, and the purification test of the polluted gas was carried out by using the titanium dioxide nanowire photocatalyst. It was found that all detected pollutants could be degraded by the catalyst, which showed that photocatalytic technology is a promising method used to solve the complex VOCs pollution problem in campus hazardous waste temporary storage.
2020, 35(2): 82-87
doi: 10.3866/PKU.DXHX201905062
Abstract:
Packed tower and plate tower were common equipment in the operation of chemical units. The calculation of the height of the packing layer in the packed tower and the determination of the number of theoretical plates in the tray tower were the key. The calculation of the height of the packing layer in the textbook was based on the mass transfer unit, and the determination of the theoretical plate in the plate tower was determined by the McCable-Thiele method, and the relationship between the number of mass transfer units and the theoretical plate was less. In this paper, The mass transfer unit number and the theoretical plate number were respectively calculated by the absorption factor method in detail, and the quantitative relationship between them was established. It could be used for the comparison of the two type towers, which had a certain guiding role for the analysis and design of the tower, and helped students to learn and understand the process of absorption and rectification unit operations.
Packed tower and plate tower were common equipment in the operation of chemical units. The calculation of the height of the packing layer in the packed tower and the determination of the number of theoretical plates in the tray tower were the key. The calculation of the height of the packing layer in the textbook was based on the mass transfer unit, and the determination of the theoretical plate in the plate tower was determined by the McCable-Thiele method, and the relationship between the number of mass transfer units and the theoretical plate was less. In this paper, The mass transfer unit number and the theoretical plate number were respectively calculated by the absorption factor method in detail, and the quantitative relationship between them was established. It could be used for the comparison of the two type towers, which had a certain guiding role for the analysis and design of the tower, and helped students to learn and understand the process of absorption and rectification unit operations.
2020, 35(2): 88-91
doi: 10.3866/PKU.DXHX201905035
Abstract:
The shape of an atomic orbital not only depends on the azimuthal quantum number l, but also associates with the magnetic quantum number m. We discussed about how to derive the shape of an atomic orbital from the numbers and shapes of the angular nodal planes, and the symmetries of distribution of all angular nodal planes when l and|m|are known. According to the|m|, the compatibility of the symmetry of an atomic orbitals have also been also discussed.
The shape of an atomic orbital not only depends on the azimuthal quantum number l, but also associates with the magnetic quantum number m. We discussed about how to derive the shape of an atomic orbital from the numbers and shapes of the angular nodal planes, and the symmetries of distribution of all angular nodal planes when l and|m|are known. According to the|m|, the compatibility of the symmetry of an atomic orbitals have also been also discussed.
2020, 35(2): 92-97
doi: 10.3866/PKU.DXHX201906020
Abstract:
Mass spectrometric analysis is a key and difficult issue in teaching of spectroscopic analysis course. Moreover, fragmentation patterns are the key points for mass spectrometric analysis. Understanding the dissociation rules of organic compounds will help the students to analyze the chemical structures. From the viewpoint of teaching practice, we review in this paper the fragmentation patterns of some common isomers such as acids-esters, alcoholsethers, and straight-chain and branched-chain alkyl groups. In addition, some classic examples were presented to help the students to grasp the fragmentation patterns as well as to improve their ability of mass spectrometric analysis.
Mass spectrometric analysis is a key and difficult issue in teaching of spectroscopic analysis course. Moreover, fragmentation patterns are the key points for mass spectrometric analysis. Understanding the dissociation rules of organic compounds will help the students to analyze the chemical structures. From the viewpoint of teaching practice, we review in this paper the fragmentation patterns of some common isomers such as acids-esters, alcoholsethers, and straight-chain and branched-chain alkyl groups. In addition, some classic examples were presented to help the students to grasp the fragmentation patterns as well as to improve their ability of mass spectrometric analysis.
2020, 35(2): 98-106
doi: 10.3866/PKU.DXHX201906022
Abstract:
This paper introduces the geometric assumptions and neglects of the pore size distribution calculated by BJH method, the arithmetic approximation for simplified calculation, the derivation process of each parameter, the calculation steps and key points of the pore size distribution. This paper also introduces the application scope of BJH method at the current instrument level, and how to further integrate the data. In order to get the required analysis and test report, references are provided for the subsequent adjustment of test parameters and improvement of test methods. Some problems often encountered in reading experimental reports are also discussed.
This paper introduces the geometric assumptions and neglects of the pore size distribution calculated by BJH method, the arithmetic approximation for simplified calculation, the derivation process of each parameter, the calculation steps and key points of the pore size distribution. This paper also introduces the application scope of BJH method at the current instrument level, and how to further integrate the data. In order to get the required analysis and test report, references are provided for the subsequent adjustment of test parameters and improvement of test methods. Some problems often encountered in reading experimental reports are also discussed.
2020, 35(2): 107-113
doi: 10.3866/PKU.DXHX201905031
Abstract:
A statistical software package is developed for the course of chemical analysis. The software calculates cumulative distribution functions and inverse cumulative distribution functions of normal, t, χ2, and F distributions; it also provides critical values for tests of statistical significance. The software is designed to substitute for traditional data tables that are insufficient and obscure. Statistical problems can be solved more efficiently with the software than with traditional data tables, which enables students to focus on understanding statistical principles and interpreting results. The software provides information through an intuitive interface, a graph, and natural interactions. Both Matlab and Android versions are presented, and free of charge.
A statistical software package is developed for the course of chemical analysis. The software calculates cumulative distribution functions and inverse cumulative distribution functions of normal, t, χ2, and F distributions; it also provides critical values for tests of statistical significance. The software is designed to substitute for traditional data tables that are insufficient and obscure. Statistical problems can be solved more efficiently with the software than with traditional data tables, which enables students to focus on understanding statistical principles and interpreting results. The software provides information through an intuitive interface, a graph, and natural interactions. Both Matlab and Android versions are presented, and free of charge.
2020, 35(2): 114-134
doi: 10.3866/PKU.DXHX201906016
Abstract:
Molecular machines have attracted significant attentions as one of the most promising aspects of chemistry for their potential applications ever since receiving the 2016 Nobel Prize in Chemistry. The molecular assembler, also called the nanofactory, is a novel type of molecular machines that are capable of controlling the chemical reactions precisely at the microscopic level. As an analog to the macroscopic factories, nanofactories are comprised of a "transporting" part, the molecular walkers, and an "assembling" part, the molecular robotic arms. In this review, we provide a brief introduction of the research progress in recent years together with analysis on the principles of designing, constructing and operating molecular assemblers. We also summarize the prospects and challenges in the research area of molecular assemblers.
Molecular machines have attracted significant attentions as one of the most promising aspects of chemistry for their potential applications ever since receiving the 2016 Nobel Prize in Chemistry. The molecular assembler, also called the nanofactory, is a novel type of molecular machines that are capable of controlling the chemical reactions precisely at the microscopic level. As an analog to the macroscopic factories, nanofactories are comprised of a "transporting" part, the molecular walkers, and an "assembling" part, the molecular robotic arms. In this review, we provide a brief introduction of the research progress in recent years together with analysis on the principles of designing, constructing and operating molecular assemblers. We also summarize the prospects and challenges in the research area of molecular assemblers.
2020, 35(2): 135-139
doi: 10.3866/PKU.DXHX201906027
Abstract:
Through the analysis of several valuable chemical contest problems, the students' spatial visualization and divergent thinking abilities were improved, and the teaching's advice was provided.
Through the analysis of several valuable chemical contest problems, the students' spatial visualization and divergent thinking abilities were improved, and the teaching's advice was provided.
2020, 35(2): 140-154
doi: 10.3866/PKU.DXHX201908044
Abstract:
