Sweetness, a kind of flavors that is related to happiness. Sweeteners interact with sweet taste receptors, which activate the reward area of the brain to releases dopamine. According to the different molecular structures, sweet molecules can be divided into sugars(sugar, sugar derivatives、sugar alcohols、glycosides), amino acids(dipeptides、proteins), sulfonamides and so on. This article will explain sweet molecules and their sweetness from the molecular structure level.

An English teaching course, General Chemistry Laboratory, is presented to the students in the School of the Gifted Youth, University of Science and Technology of China. The teaching content of the course is comprehensive and novel, taking full advantage of students' talent for calculation and inference. The flipped classroom is adopted so as to get students more engaged in science and develop the spirit of discovery. Intense practices in English language.as well as communication with foreign experts or TA are implemented in the course. Both professional English and the creativity of the students are enhanced through the course.

This paper introduces the definite measures to implement the problem-based Learning (PBL) mode in inorganic chemistry teaching, including the reorganization of teaching content, the adoption of interactive teaching methods, and the design of innovative practical work. We expect, with introducing these strategies into the traditional inorganic chemistry teaching, that the students' abilities of autonomic learning, innovative thinking, summarization, cooperation and expression can be cultivated, improved or strengthened effectively. And the teaching efficiency and quality can be promoted dramatically.

The differences between traditional education and innovative education are compared, and the necessity of using problem-driven teaching method is also analyzed in this paper. The implementation process and some problems of problem-driven teaching method are introduced by example of colloid chemistry. Problem-driven teaching method can effectively mobilize students' interest and enthusiasm in self-learning and self-exploration. Classroom discussion atmosphere is active, and teaching objectives can be effectively achieved.

According to the characteristics and teaching practice of general chemistry, this article analysed the current problems in the traditional teacher-centered teaching mode and presented the necessities of practicing student-centered teaching mode. Some measures for creating student-centered teaching mode in general chemistry course teaching were presented from four aspects, which including teaching concepts, teaching contents, teaching processes and evaluation methods. The integration of the teaching contents should be based on the principle of conciseness, the principle of modules, the principle of practical life, and the principle of openness. The four-links and six-steps teaching patterns were put forward to optimize the teaching process. The open and multiple interactive evaluation systems were set up to evaluate the effectiveness of education inside classroom.

Aiming at the cultivation of innovative talents in universities, a research-oriented comprehensive chemical experiment was designed. Using citric acid and urea as raw materials, carbon quantum dots with blue emission were prepared by hydrothermal method. And their ultraviolet-visible absorption and fluorescence spectra were characterized. The application of carbon quantum dots in folic acid detection was further studied. The experiment involves the preparation, characterization and applications of nanomaterials, which is suitable for senior undergraduates as a research-oriented comprehensive chemical experiment. And the experiment may be helpful to stimulate students' interests in research and cultivate students' scientific research thinking.

The exploration for the tandem synthesis of (poly)sulfonates by organic base in one pot was utilized as an innovative experiment. In this project, cyanosilylation reaction of aldehyde and Sulfur(Ⅵ) Fluoride Exchange reaction were studied separately, including the effects of the substrate structure and organic base as catalyst on the reaction activity. In addition, the feasibility of connecting the two reactions in one pot was preliminarily explored. Through the innovation training program, it was benefit for students to understand the knowledge of organic chemistry and analytical chemistry in class, hence to achieve the combination of theory with practice.

In this experiment, Pickering emulsions were stabilized by nanoparticles functionalized through absorption of surfactant molecules. By investigating the double phase inversion of emulsions, we explored the adsorption mode of surfactant molecules on the surface of nanoparticles, deepened students' understanding of the relevant principles of surface and interface chemistry, and cultivated students' comprehensive experimental ability and analytical reasoning ability.

This paper introduces a scalable analytical chemistry teaching experiment:coordination titration method for the determination of calcium ion in rape. This experiment involves the knowledge and operation of the coordination titration method in the field of analytical chemistry, which is helpful for students' theoretical knowledge learning and experimental skills mastering. It is recommended as a basic experiment for freshmen. Because calcium ions participate in the metabolic process of rape, it plays a key role in the growth and development of rape. Therefore, it is necessary to accurately determine the calcium content in rape to facilitate timely detection of problems, so the experiment itself has very important application value. In this experiment, under the condition of pH=12~13, direct titration was carried out with EDTA standard solution. Calcium carboxylic acid was used as indicator, the interference of iron and manganese ions was eliminated by triethanolamine, and the interference of magnesium ion and phosphate ion was inhibited by dextrin. Comparing this method with the national standard method (flame atomic absorption method), there is no significant difference between the data obtained by the two methods. It is reliable and accurate to determine the calcium ion content in rape by this method.

A typical comprehensive chemical experiment was designed for undergraduates, in which metal nanoparticles were prepared by colloid chemistry method and were used to catalyze a redox reaction to study the reaction kinetics. First, sphere or flake-like silver nanoparticles with different size were prepared via seed-growth method and subsequently purified by centrifugation. Then, the purified silver samples were employed as heterogeneous catalysts in the reduction of 4-nitrophenol by sodium borohydride. Moreover, the catalytic reaction kinetics was investigated to analyze the apparent reaction rate constants and the activity of silver nanoparticle catalysts. This experiment can train the student ability for the preparation of nanomaterials and the process tracking of reaction kinetics, and also promote students to further understand the mechanism of heterogeneous catalysis and familiarize the operation of spectral instruments.

“The Questionnaire of Teacher Beliefs of Science Normal Students” was used to investigate the teacher beliefs held by 92 chemistry normal students in a university in Guangzhou after educational practice. It was found that chemistry normal students were mainly expressing constructive type in the belief of science teaching and the belief of science learning, and they mainly expressed traditional type in the belief of nature of science. There were 16 ways in which chemistry normal students' science teaching, science learning and nature of science belief orientation were combined. Among them, the way, the belief of science teaching expressed constructive type and the belief of science learning expressed constructive type and the nature of science belief expressed traditional type, was the main combination way. The relationship between the science teaching, the science learning and the nature of science belief of the chemistry normal students was mainly characterized by the contact, and rarely appeared to be divided.

According to the requirement of combining basic courses with professional training, the comprehensive research-oriented experiment on the synthesis, characterization of acrylate terpolymer and evaluation of pour point reduction performanceis is designed. The experiment includes the investigation of synthesis conditions, the infrared spectrum characterization of products, the determination of lowering pour point effect, and the observation by polarizing microscope and so on. Through the four steps of “synthesis-characterization-performance-mechanism”, this experiment enables students to have an overall understanding of the research and development of pour point depressant, and guides students from the study of theoretical knowledge to the solution of practical problems and then scientific research step by step. Teaching practice shows that this experiment can fully mobilize students' interests and enthusiasm, and cultivate students' ability of comprehensive application of knowledge and practical innovation.

It is difficult for students to learn basic chemistry because of its abstruse theory and complicated calculation. In this procedure, the ability of active learning of students are been promoted. The students are easy to accept chemical knowledge. It has improved the teaching quality and effect greatly. This paper takes the teaching design of “Buffer Solution and Its Mechanism” as an example, expounds the application of theblendedteaching mode in classroom teaching.

Based on the deficiency situation of knowledge and ability of master students,in order to strengthen the practical ability of the academic chemistry master students, we put forward the theory education mode with the cultivation of students' scientific research ideas as a center and constructing “Synergy 1+3” training mode. In particular, emphasize the influence of the humanistic education ideas of the research group on the development of students' practical ability.

In order to combat shallow learning in online study,virtual role-based dialogue was innovatively applied for the construction of online course materials in this research. Taking the case of analytical chemistry experiment as an example, the development of the online course materials, the design of different dialogue types and the qualitive evaluation based on sample interview were presented. According to this research, the online course with virtual role-based dialogue can notably improve positive emotional factors, help to attract learners' interests, maintain their attention and decompose their cognitive load. The sense of immersion and cognitive conflict can induce deep learning process of “conflict-reflection-construction” and thus strengthen higher-order thinking skills of the learners. It is also found that beginners showed a significant preference for online course resources with virtual role-based dialogue, which reveals its value in the application in introductory courses and flip classes. The above conclusions were further verified in its preliminary application via a questionnaire. In addition, more challenging dialogues between students and teachers should be developed, for the inspiration of innovative thinking and creativity in the further improvement of the online course.

In order to investigate the real effect of safety education in chemistry related majors in university, a questionnaire survey was conducted towards 670 undergraduates in the college of chemistry and chemical engineering, Tianjin university of Technology. The items of the questionnaire included the students' attitude and interests towards chemistry, safety awareness, safety experience and safety practice. The results showed that safety awareness was significant different in grade; lab anxiety and safety practice was significant different in gender. The regression analysis demonstrated that the safety awareness and chemistry interests was positively correlated with the safety practice. According to the results of statistical analysis,some improvement suggestions were proposed. The continuity of safety education should be focused on; more attention should be paid to students' psychology security; and subjective initiative should be strengthened in the future.

This paper discusses tense usages in scientific papers under the theoretical framework of Swales' move analysis and Kanoksilapatham's structure of moves and steps. First, 60 papers were selected from the top international journals in material and chemistry fields. Then, a move analysis of the sample papers was conducted, finding a structure of 9 moves and 14 steps in the sample papers. Finally, tense usage rules were generalized through the means of communicative motives analysis of each moves and steps. Meanwhile, we also have the following findings: (1) the results of moves and steps in sample papers are basically in agreement with J. Swales and Kanoksilapatham's framework; (2) the use of tense should be decided not only by its grammatical functions of tenses but by the communicative functions of each step and move as well.

Working curve has an important role in scientific quantitative analysis. However, the question about how to utilize existing data for the most accurate result remains unsolved and debatable. Especially when we use the data from the working curve for further calculation, different methods can lead to different errors. Thispaper introduced and contrasted the accuracy of four calculation methods: direct average, weighed average, quadratic regression, and co-regression, through theoretical analysis and experiments. Futhermore, their advantages and disadvantages were summarized as well as the range of application, in order to bring some inspiration to the lecturing and research by scientific workers.

The essential purposes for organizing and conducting various undergraduate chemistry contests are to develop students with well rounded lab skills and promote their motivations towards innovative thinking. Focusing on these objectives there are some significant reforms being carried out on Zhejiang Province Undergraduate College Chemistry Contest in recent years with the emphasis on assessing the participant's innovative and comprehensive capabilities. Such reforms have enhanced the contest with broader benefits and positive impacts. Taking the 11th Zhejiang Province Undergraduate College Chemistry Contest in 2019 as a case study, this paper provides an in-depth analysis on the various aspects of the contest, including the competition rules, the contest layouts, research topics selected, and the scoring guidelines. The issues observed in the contest are also investigated with recommendations for future improvement.