Login In
2017 Volume 32 Issue 11
2017, 32(11): 1-6
doi: 10.3866/PKU.DXHX201707015
Abstract:
Organic semiconductors are the basis of organic electronics and the introduction of heteroatoms has greatly diversified these materials. BN unit is isoelectric to CC unit, which has attracted much attention of chemists due to its effect on the material properties. This short review summarizes the progress of the synthesis and electronic application of BN-embedded polycyclic aromatic hydrocarbons.
Organic semiconductors are the basis of organic electronics and the introduction of heteroatoms has greatly diversified these materials. BN unit is isoelectric to CC unit, which has attracted much attention of chemists due to its effect on the material properties. This short review summarizes the progress of the synthesis and electronic application of BN-embedded polycyclic aromatic hydrocarbons.
2017, 32(11): 7-11
doi: 10.3866/PKU.DXHX201707011
Abstract:
This paper discusses the application and assessment of "flipped classroom" in general chemistry for the minority class. It is concluded that the flipped classroom teaching mode fully arouses the enthusiasm and initiative of the students. The teaching level of the teachers is also improved. The flipped classroom achieves better teaching results than the normal mode. It provides a successful experience for the adoption of "flipped classroom" teaching mode into general chemistry course for students whose native language is not Chinese.
This paper discusses the application and assessment of "flipped classroom" in general chemistry for the minority class. It is concluded that the flipped classroom teaching mode fully arouses the enthusiasm and initiative of the students. The teaching level of the teachers is also improved. The flipped classroom achieves better teaching results than the normal mode. It provides a successful experience for the adoption of "flipped classroom" teaching mode into general chemistry course for students whose native language is not Chinese.
2017, 32(11): 12-16
doi: 10.3866/PKU.DXHX201706032
Abstract:
Based on the student-centered education concept and training objectives of high-quality talents, the teaching method of students' participation was proposed for organic chemistry. This method could help the students to improve their consciousness of autonomous learning and their comprehensive quality. Detailed process of this method was described combined with the teaching of organic chemistry.
Based on the student-centered education concept and training objectives of high-quality talents, the teaching method of students' participation was proposed for organic chemistry. This method could help the students to improve their consciousness of autonomous learning and their comprehensive quality. Detailed process of this method was described combined with the teaching of organic chemistry.
2017, 32(11): 17-22
doi: 10.3866/PKU.DXHX201707006
Abstract:
Engineering chemistry is a basic disciplinary course for the students majored in energy and environmental systems engineering. The aim of this course is to promote the capacity for independent thinking and solving the practical problems using chemistry knowledge. Herein, a detailed educational analysis and practice of the course set up in our faculty is described. The extracurricular tutorship and the examination of course are also focused. Due to the contradiction between limited lecture hours and overloaded teaching assignment, we revise course content, teaching methods and the curriculum system of engineering chemistry. In addition, experimental teaching is expanded and optimized. This paper proposes a new teaching philosophy. And the teaching quality of engineering chemistry has been improved.
Engineering chemistry is a basic disciplinary course for the students majored in energy and environmental systems engineering. The aim of this course is to promote the capacity for independent thinking and solving the practical problems using chemistry knowledge. Herein, a detailed educational analysis and practice of the course set up in our faculty is described. The extracurricular tutorship and the examination of course are also focused. Due to the contradiction between limited lecture hours and overloaded teaching assignment, we revise course content, teaching methods and the curriculum system of engineering chemistry. In addition, experimental teaching is expanded and optimized. This paper proposes a new teaching philosophy. And the teaching quality of engineering chemistry has been improved.
2017, 32(11): 23-26
doi: 10.3866/PKU.DXHX201706023
Abstract:
Teaching skill is not only a vocational skill for teacher-oriented students, but also an important part of teacher education. A modular practice teaching system is proposed by analyzing the requirements of teachers' vocation. The paper described our practices and explorations on essential teaching skills, such as the linguistic skill, the writing skill, media technologies, the teaching design, chemistry experiments, teaching, and the speaking lesson.
Teaching skill is not only a vocational skill for teacher-oriented students, but also an important part of teacher education. A modular practice teaching system is proposed by analyzing the requirements of teachers' vocation. The paper described our practices and explorations on essential teaching skills, such as the linguistic skill, the writing skill, media technologies, the teaching design, chemistry experiments, teaching, and the speaking lesson.
2017, 32(11): 27-31
doi: 10.3866/PKU.DXHX201707010
Abstract:
This paper briefly states that doing teaching research well is the key to improve the quality of education and teaching, and writing education and teaching papers is a good way to promote teaching research. The purpose and content of writing teaching papers are clarified. Meanwhile, taking the papers written in teaching research as examples, this paper emphasizes that the foundation of good writing comes from solid teaching practice, the skill of good writing derives from scientific research, and the practice of good writing originates from taking teaching research as the scientific research.
This paper briefly states that doing teaching research well is the key to improve the quality of education and teaching, and writing education and teaching papers is a good way to promote teaching research. The purpose and content of writing teaching papers are clarified. Meanwhile, taking the papers written in teaching research as examples, this paper emphasizes that the foundation of good writing comes from solid teaching practice, the skill of good writing derives from scientific research, and the practice of good writing originates from taking teaching research as the scientific research.
2017, 32(11): 32-44
doi: 10.3866/PKU.DXHX201707007
Abstract:
Redox-flow batteries (RFBs) are promising candidates for sustainable energy storage systems. Compared to traditional inorganic RFBs, TEMPO-based RFBs is more advantageous in low cost, high voltage, excellent reversibility and tunable redox-active material structure. In this article, we review the research progress of RFBs using TEMPO and its derivatives as redox-active materials, introduce the related experimental methods and propose the plausible directions for future research.
Redox-flow batteries (RFBs) are promising candidates for sustainable energy storage systems. Compared to traditional inorganic RFBs, TEMPO-based RFBs is more advantageous in low cost, high voltage, excellent reversibility and tunable redox-active material structure. In this article, we review the research progress of RFBs using TEMPO and its derivatives as redox-active materials, introduce the related experimental methods and propose the plausible directions for future research.
2017, 32(11): 45-50
doi: 10.3866/PKU.DXHX201706031
Abstract:
In physical chemistry experiment, straight and U-shaped transfer tubes are often used for determining Cu2+ ion transference number by Hittorf method. When a U-shaped transfer tube is used, the result calculated from the concentration change of cathode chamber solution usually has a significant error. The concentration distributions of CuSO4 solution with height in the straight, U and nshaped transfer tubes after electrolysis were investigated via spectrophotometry, using CuSO4 and Cu hoops as electrolyte and electrodes, respectively. It is found that the shape of transfer tube has a great effect on the concentration of central chamber solution. Because the cathode locates at the bottom of the U-shaped and n-shaped transfer tubes, the concentration of central chamber solution changes a lot after electrolysis due to convection caused by the gravity effect, and the concentration of cathode chamber solution is also affected. It would bring a significant error to the measurement of ion transference number. Contrarily, this effect is ignorable if a straight-shaped transfer tube is used, and thus more accurate result can be obtained.
In physical chemistry experiment, straight and U-shaped transfer tubes are often used for determining Cu2+ ion transference number by Hittorf method. When a U-shaped transfer tube is used, the result calculated from the concentration change of cathode chamber solution usually has a significant error. The concentration distributions of CuSO4 solution with height in the straight, U and nshaped transfer tubes after electrolysis were investigated via spectrophotometry, using CuSO4 and Cu hoops as electrolyte and electrodes, respectively. It is found that the shape of transfer tube has a great effect on the concentration of central chamber solution. Because the cathode locates at the bottom of the U-shaped and n-shaped transfer tubes, the concentration of central chamber solution changes a lot after electrolysis due to convection caused by the gravity effect, and the concentration of cathode chamber solution is also affected. It would bring a significant error to the measurement of ion transference number. Contrarily, this effect is ignorable if a straight-shaped transfer tube is used, and thus more accurate result can be obtained.
2017, 32(11): 51-56
doi: 10.3866/PKU.DXHX201706014
Abstract:
A research-type comprehensive experiment was introduced:a facile microwavehydrothermal synthesis and characterization of CuInS2/ZnS composite quantum dots (QDs). In the experiment, water-soluble CuInS2/ZnS composite QDs were synthesized by a two-step microwavehydrothermal method using reagents of Cu2+, In3+, Zn2+ and S2- with glutathione as the stabilizer. The structure of the prepared composite QDs was characterized by X-ray diffraction (XRD) and transmittance electronic microscopy (TEM), and optical properties were characterized by UV-Visible absorption spectroscopy, photoluminescence spectroscopy, fluorescence lifetime and fluorescence imaging. The effects of temperature, time and the component in the precursors on the fluorescent properties were explored. Scientific research methods and thinking ability of students are trained by designing and accomplishing the experiment.
A research-type comprehensive experiment was introduced:a facile microwavehydrothermal synthesis and characterization of CuInS2/ZnS composite quantum dots (QDs). In the experiment, water-soluble CuInS2/ZnS composite QDs were synthesized by a two-step microwavehydrothermal method using reagents of Cu2+, In3+, Zn2+ and S2- with glutathione as the stabilizer. The structure of the prepared composite QDs was characterized by X-ray diffraction (XRD) and transmittance electronic microscopy (TEM), and optical properties were characterized by UV-Visible absorption spectroscopy, photoluminescence spectroscopy, fluorescence lifetime and fluorescence imaging. The effects of temperature, time and the component in the precursors on the fluorescent properties were explored. Scientific research methods and thinking ability of students are trained by designing and accomplishing the experiment.
2017, 32(11): 57-64
doi: 10.3866/PKU.DXHX201707003
Abstract:
A new comprehensive chemical experiment for college students is introduced, including the synthesis and characterization of a fluorescent probe based on BODIPY, as well as its application in detection of Cu2+ ions. This experiment is from the achievements of scientific research. It includes the synthesis of 3,5-dichloro-8-(4-tolyl)BODIPY, the synthesis of a fluorescent probe based on BODIPY, and the detection of metal ions by UV-Vis spectrometer and Fluorescence spectrometer. Students' interest in fluorescent sensor based on BODIPY research can be stimulated and cultivated by this experiment. Furthermore, the experiment involves the knowledge of organic chemistry, instrumental analysis and applied spectroscopy, which can be used to improve students' experimental skills, comprehensive and innovative abilities. Thus, it is recommended to be included in the advanced comprehensive chemical experiment course.
A new comprehensive chemical experiment for college students is introduced, including the synthesis and characterization of a fluorescent probe based on BODIPY, as well as its application in detection of Cu2+ ions. This experiment is from the achievements of scientific research. It includes the synthesis of 3,5-dichloro-8-(4-tolyl)BODIPY, the synthesis of a fluorescent probe based on BODIPY, and the detection of metal ions by UV-Vis spectrometer and Fluorescence spectrometer. Students' interest in fluorescent sensor based on BODIPY research can be stimulated and cultivated by this experiment. Furthermore, the experiment involves the knowledge of organic chemistry, instrumental analysis and applied spectroscopy, which can be used to improve students' experimental skills, comprehensive and innovative abilities. Thus, it is recommended to be included in the advanced comprehensive chemical experiment course.
2017, 32(11): 65-68
doi: 10.3866/PKU.DXHX201706024
Abstract:
Taking copper plated on the surface of iron nail as an example, the problems of uneven copper coating and easy falling off from the iron surface were discovered based on the direct redox reaction of Cu2+ and Fe. On the basis of these problems, the students reviewed literatures, analyzed the problems, designed related experimental schemes, and performed experimental operations under the guidance of tutors, the problems were resolved and a uniform copper coating surface was obtained. Via the considerations of the problem discovery, problem analysis, literature review, experimental design, and problem resolving, junior students' scientific research thinking were cultivated.
Taking copper plated on the surface of iron nail as an example, the problems of uneven copper coating and easy falling off from the iron surface were discovered based on the direct redox reaction of Cu2+ and Fe. On the basis of these problems, the students reviewed literatures, analyzed the problems, designed related experimental schemes, and performed experimental operations under the guidance of tutors, the problems were resolved and a uniform copper coating surface was obtained. Via the considerations of the problem discovery, problem analysis, literature review, experimental design, and problem resolving, junior students' scientific research thinking were cultivated.
2017, 32(11): 69-74
doi: 10.3866/PKU.DXHX201707008
Abstract:
Mass balance equation (MBE), charge balance equation (CBE), and proton balance equation (PBE) are commonly used in computations of chemical equilibria. This paper presented a proof that CBE can be derived from MBE, so it is not an independent equation. Although CBE is not a necessary condition, it is more efficient than MBE in chemical equilibria involving acid and base. The higher efficiency of CBE in this regard was found to be a variety of H+ sources. The conclusions are consistent with practical computations that MBE is the primary equation in computations of complexation, redox and precipitation equilibrium, whereas CBE is the primary equation in those of acid-base equilibrium. PBE is neither an independent equation, and only applicable in acid-base equilibrium; its function is completely and more efficiently implemented by CBE. So it is unnecessary to keep PBE in the textbook of quantitative analytical chemistry. This research clarifies the independent equation in chemical equilibria, which not only increases computation efficiency, but also makes the theoretical framework concise and clear.
Mass balance equation (MBE), charge balance equation (CBE), and proton balance equation (PBE) are commonly used in computations of chemical equilibria. This paper presented a proof that CBE can be derived from MBE, so it is not an independent equation. Although CBE is not a necessary condition, it is more efficient than MBE in chemical equilibria involving acid and base. The higher efficiency of CBE in this regard was found to be a variety of H+ sources. The conclusions are consistent with practical computations that MBE is the primary equation in computations of complexation, redox and precipitation equilibrium, whereas CBE is the primary equation in those of acid-base equilibrium. PBE is neither an independent equation, and only applicable in acid-base equilibrium; its function is completely and more efficiently implemented by CBE. So it is unnecessary to keep PBE in the textbook of quantitative analytical chemistry. This research clarifies the independent equation in chemical equilibria, which not only increases computation efficiency, but also makes the theoretical framework concise and clear.
2017, 32(11): 75-80
doi: 10.3866/PKU.DXHX201707026
Abstract:
The experimental test and design ideals of organic experiment for the 1st chemistry experiment tournament of Fujian undergraduates were introduced. The evaluation standards of the contest, the summary of the results, and the problems found in the competition were also illustrated.
The experimental test and design ideals of organic experiment for the 1st chemistry experiment tournament of Fujian undergraduates were introduced. The evaluation standards of the contest, the summary of the results, and the problems found in the competition were also illustrated.
2017, 32(11): 81-85
doi: 10.3866/PKU.DXHX201704028
Abstract:
The essay focuses on the detailed analysis and solutions of the two questions in the 30th Chemistry Olympiad and conducts further discussion on the subjects. First, the scientific background of the Nierate test was introduced and the analysis of the information of the magnetic moment was discussed in depth; second, the background and solution of the "methanol to hydrogen" problem in the final competition were elucidated. The author aims to broaden the research background and relevant knowledge of the two questions, thus encouraging readers to understand comprehensively the scientific thought behind the questions and enjoy the learning of chemistry.
The essay focuses on the detailed analysis and solutions of the two questions in the 30th Chemistry Olympiad and conducts further discussion on the subjects. First, the scientific background of the Nierate test was introduced and the analysis of the information of the magnetic moment was discussed in depth; second, the background and solution of the "methanol to hydrogen" problem in the final competition were elucidated. The author aims to broaden the research background and relevant knowledge of the two questions, thus encouraging readers to understand comprehensively the scientific thought behind the questions and enjoy the learning of chemistry.
2017, 32(11): 86-96
doi: 10.3866/PKU.DXHX2017070312
Abstract:
