• Title/Summary/Keyword: history of chemistry

Search Result 130, Processing Time 0.028 seconds

Development and Application of Teaching·Learning Material Concept of Resonance Using the History of Chemistry (화학사적 교수법을 적용한 공명(共鳴) 개념 교수·학습 자료 개발 및 적용)

  • Kim, Kyung-Im;Lee, Woo-Bung
    • Journal of Science Education
    • /
    • v.34 no.2
    • /
    • pp.342-358
    • /
    • 2010
  • By using the concept of 'Resonance' in benzene which stems from a unit dealing with the carbocyclic compounds which is in a text 'Chemistry I', I developed teaching methods based on the history of science. This study was executed to analyze the effect by applying these methods. Seventy 3rd grade male students, who are attending a high school located in the Pohang area were used in this study. I investigated the level of the relative difficulty and the degree of scholastic achievement from each treatment group and controlled group using the concept of Resonance from the preceeding study. In this study, these 70 students divided into two classes- a traditional lecture group consisting of male 35 student, and a group using the history of chemistry consisting of the remaining 35 student and after a specified period, their scholastic achievement was analyzed. As a result of this study, the treatment group scored much higher (50.143) than the controlled group(25.429) in average score and showed significant difference between two groups. Through this study was based on the history of chemistry, after scientists let them realize the process of improving science attitude, and think like scientists, giving conceptual class can get much more efficiency and durability for learning.

  • PDF

History and current status of vinegar industry development (식초 산업의 발전사와 최근 현황)

  • Kim, Hyeon-Wee
    • Food Science and Industry
    • /
    • v.55 no.1
    • /
    • pp.74-94
    • /
    • 2022
  • With the discovery of metabolic mechanisms of alcohol fermentation and acetic acid fermentation in the 1800s and 1900s, the history of traditional vinegar became a turning point for changing to the history of science and technology. Since then, innovation in vinegar production has occurred, and the era of full-scale mass industrialization has opened. The most modern method, submerged fermentation, has improved the vinegar production process to produce much higher quality vinegar and provide vinegar with high productivity and quality uniformity. Innovative research for vinegar production is underway as various approaches have been developed to increase fermentation efficiency, reduce costs, and shorten fermentation time due to the trend of combining existing technologies and advanced technologies. Now that the development of the vinegar industry is currently focused on vinegar engineering, multidisciplinary approaches in various fields such as microbiology, chemistry, food technology, process engineering, and molecular biology are needed.

Porous Coordination Polymers of Zinc(II)-dicarboxylate-diamine and Their Gas Sorption Properties

  • Chun, Hyung-Phil
    • Korean Journal of Crystallography
    • /
    • v.16 no.2
    • /
    • pp.61-65
    • /
    • 2005
  • Despite a short history, the research on porous coordination polymers is gaining importance in inorganic chemistry thanks to facile synthesis, unambiguous characterization by X-ray diffraction and potentials as high-surface-area materials. Recently, gas sorption properties of various porous materials are under active investigations in order to know whether it is possible to store industrially important gases through physisorption, and porous coordination polymers are one of the most promising candidates for such a purpose. This article reviews two recent papers reporting a series of isomorphous frameworks based on Zn(II), dicarboxylate and diamine ligands and their gas sorption properties.

Overview of Herbal Medicine Practice in the USA

  • Staba, E. John;Staba, Joyce E.
    • Natural Product Sciences
    • /
    • v.4 no.1
    • /
    • pp.1-8
    • /
    • 1998
  • An overview of the history of the evolution of health practice in the United States. The development of selected laws regulating the marketing of botanical commodities and recent efforts to standardize them. Some consideration is given to the clinical testing and clinical use of botanical commodities.

  • PDF

N-tetradecane/Water Emulsion as a Low-cost Phase Change Material for Efficient Packaging and Shipping of Vaccines

  • Dao, Van-Duong;Choi, Ho-Suk
    • Clean Technology
    • /
    • v.23 no.3
    • /
    • pp.325-330
    • /
    • 2017
  • This study presents the preparation of n-tetradecane-in-water emulsions with different weight ratios of n-tetradecane and water, and their potential application in packaging and shipping vaccines. The size and distribution of the n-tetradecane droplets are characterized using optical microscopy and light scattering methods, respectively. The thermal properties of the emulsions are determined using the T-history method. In the results, the emulsions, which are comprised of 17 ~ 30 wt% oil, 3 wt% surfactant, and 67 ~ 80 wt% water, are stable and have droplet sizes in the range of 100 to 800 nm. The thermal properties demonstrate that subcooling is prevented through increasing the droplet size. The results indicate that the n-tetradecane/water emulsions containing 25 ~ 35 wt% n-tetradecane, with a melting point of $2{\sim}8^{\circ}C$ and a latent heat of $227.0{\sim}250.8kJ\;kg^{-1}$, are good candidate materials for packaging and shipping vaccines.

Elemental analysis by neutron induced nuclear reaction - Nuclear track method for the analysis of fissile materials

  • Ha, Yeong-Keong;Pyo, Hyung Yeol;Park, Yong Joon;Jee, Kwang Yong;Kim, Won Ho
    • Analytical Science and Technology
    • /
    • v.18 no.4
    • /
    • pp.263-270
    • /
    • 2005
  • Nuclear track is an useful tool for elemental analysis of radionuclides, such as uranium, plutonium and thorium, etc., and for elements undergoing nuclear reactions with thermal neutrons such as lithium and boron. This method has various application fields such as detecting fissionable radionuelides, measuring the fission rate in nuclear technology, analyzing cosmic radiation from meteorite, calculating the age of minerals as well as their history, etc. Track registration method has been applied to the microscopic analysis of boron and fissionable element such as uranium in KAERI. This report reviews the theoretical background of the nuclear track formation, practical procedures to obtain etched tracks and a perspective of the future.