• Title/Summary/Keyword: Valuable material

Search Result 503, Processing Time 0.029 seconds

Development and Validation of the Korean Traditional Music Ability Test for Young Children (유아국악능력 검사도구 개발 및 양호도 검증)

  • Park, Hyoung-Shin;Kim, Young-Ok
    • Korean Journal of Child Studies
    • /
    • v.28 no.1
    • /
    • pp.37-54
    • /
    • 2007
  • The purpose of this study was the development and validation of a test of young children's understanding and their ability to represent the elements of traditional Korean music. The test was reviewed by professional groups and modified by preliminary testing. In its final form, the Korean Traditional Music Ability Test(KTMAT) for 4- to 6-year-old children consists of 43 items covering understanding and ability to represent Changdan(Changdanhyung, Bak, Bbareugi and Semyeorim) and Garak(Eumjeong and Sikimshae). Item analysis, reliability and validity tests were statistically significant. The KTMAT is an evaluation tool that can be used as basic material for developing children's musical ability, and it can provide valuable information showing direction for children's Korean traditional music education.

  • PDF

Electrochemically Fabricated Alloys and Semiconductors Containing Indium

  • Chung, Yonghwa;Lee, Chi-Woo
    • Journal of Electrochemical Science and Technology
    • /
    • v.3 no.3
    • /
    • pp.95-115
    • /
    • 2012
  • Although indium (In) is not an abundant element, the use of indium is expected to grow, especially as applied to copper-indium-(gallium)-selenide (CI(G)S) solar cells. In future when CIGS solar cells will be used extensively, the available amount of indium could be a limiting factor, unless a synthetic technique of efficiently utilizing the element is developed. Current vacuum techniques inherently produce a significant loss of In during the synthetic process, while electrodeposition exploits nearly 100% of the In, with little loss of the material. Thus, an electrochemical process will be the method of choice to produce alloys of In once the proper conditions are designed. In this review, we examine the electrochemical processes of electrodeposition in the synthesis of indium alloys. We focus on the conditions under which alloys are electrodeposited and on the factors that can affect the composition or properties of alloys. The knowledge is to facilitate the development of electrochemical means of efficiently using this relatively rare element to synthesize valuable materials, for applications such as solar cells and light-emitting devices.

Exploratory Study on Causality of Foreign Exchange Exposure and Hedge Strategy: Systems Thinking Approach (환노출과 환노출 완화 전략의 인과관계에 관한 탐색적 연구 : 시스템 사고에 의한 접근)

  • Eom, Jae-Gun;Chung, Chang-Kwon;Sul, Wonsik
    • Korean System Dynamics Review
    • /
    • v.15 no.2
    • /
    • pp.97-131
    • /
    • 2014
  • The purpose of this study is to analyze Foreign Exchange(FX) exposure and FX hedge strategy based on the systems thinking perspective using causal loop diagrams. FX exposure has been a critical issue on a business management. Many studies in Korea have researches on variables which make effects to the company value. This study displays causal loop diagrams(CLDs) on these issues. In order to make CLD more objective, most causalities are articulated from recent 72 studies (1998~2013) of domestic top journals. This approach is valuable in that it is the first try to draw all the causalities from various literature review regarding FX exposure and FX hedge strategy. This study is expected to make a useful and basic material to research the financial issues of corporate, as the first research to dynamically understand FX exposure and FX hedge strategy.

  • PDF

A Study on Manufacturing of Paper Plastics Based on Biomass and Their Applications (바이오매스 기반 종이 플라스틱의 제조 및 응용에 대한 고찰)

  • Yoon, KwangSik;Lee, Dong-Eun;Cho, Daemyeong
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
    • /
    • v.26 no.1
    • /
    • pp.25-31
    • /
    • 2020
  • Recently, applications of biomass-based plastics have increased according to the eco-friendly policy of the reduction of carbon dioxide emissions in domestic and foreign government. In this study, a paper plastic composite was produced by compounding polypropylene and micronized paper powder that was prepared using dry pulverization technology. Subsequently, the specimen of paper plastic was verified with mechanical properties, formability and product safety test to confirm the suitable packaging materials for food packaging. Paper plastics showed slightly lower mechanical properties than currently commercialized PP composites. However, paper plastics are valuable materials as environmentally friendly carbon-reducing material because of high biocarbon content, light weight features and applicability of existing manufacturing machines or system.

Finite Element Analysis of the Non-axisymmetric Extrusion Process (비축대칭 압출 공정의 유한 요소 해석)

  • 신현우
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 1992.03a
    • /
    • pp.27-46
    • /
    • 1992
  • In this study a new simplified three-dimensional numerical method and the associated computer program have been developed to simulate the non-axisymmetric extrusion processes. The two-dimensional rigid-plastic finite element method under the generalized plane-strain condition, is combined with the slab method. To define the die geometry for non-axisymmetric extrusion, area mapping technique was used. Streamlined die surface was used to miniminze the total extrusion pressure. Extrusion of square, hexagonal and "T" section from round billet have been simulated and experimented with a model material. The computed results were in good agreement with the experiments in cross-sectional grid distortion. Computational results will be valuable for designing tool geometries and corresponding processes.

  • PDF

American Ginseng: Research Developments, Opportunities, and Challenges

  • Punja, Zamir K.
    • Journal of Ginseng Research
    • /
    • v.35 no.3
    • /
    • pp.368-374
    • /
    • 2011
  • American ginseng (Panax quinquefolius L.) is grown in some regions of the USA and Canada and marketed for its health promoting attributes. While cultivation of this plant species has taken place in North America for over 100 years, there are many challenges that need to be addressed. In this article, the current production method used by growers is described and the challenges and opportunities for research on this valuable plant are discussed. These include studies on pharmacological activity, genetic diversity within the species, genetic improvement of currently grown plants, molecular characterization of gene expression, and management of diseases affecting plant productivity. The current research developments in these areas are reviewed and areas requiring further work are summarized. Additional research should shed light on the nature of the bioactive compounds and their clinical effects, and the molecular basis of active ingredient biosynthesis, and provide more uniform genetic material as well as improved plant growth, and potentially reduce losses due to pathogens.

와이어 인발가공에 있어서 AE법의 적용에 관한 연구

  • 박준서;최만용;한응교;삼경언
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 1991.11a
    • /
    • pp.95-100
    • /
    • 1991
  • From a manufacturing standpoint it would be desirable to monitor the degradation of drawing die, that is essential for the maintenance of quality, the evaluation of product integrity and the reducing scrap. Acoustic emission is powerful method in monitoring fine wire drawing process, especially in detecting the die fracture at early stage. Experiments at so suggested that acoustic emission signals contained valuable information regarding the stage of a drawing process such as the surface appearance of products and the condition of lubrication. Using these informations makes AE monitoring techniques a possible tool in monitoring the drawing process operation. In order to approach this, this paper discusses the nature of acoustic emission signals produced in drawing process under various conditions. Experimental results are presented which illustrate the effects of wire and die material, lubricants, and drawing speed on the generation and the mean voltage level of acoustic emission signals. The results from these tests give controlling factors of acoustic emission generation.

  • PDF

Measurement of III-V Compound Semiconductor Characteristics using the Contactless Electroreflectance Method

  • Yu, Jae-In;Choi, Soon-Don;Chang, Ho-Gyeong
    • Journal of Electrical Engineering and Technology
    • /
    • v.6 no.4
    • /
    • pp.535-538
    • /
    • 2011
  • The electromodulation methods of photoreflectanceand the related technique of contactless electroreflectance(CER) are valuable tools in the evaluation of important device parameters for structures such as heterojunction bipolar transistors, pseudomorphic high electron mobility transistors, and quantum dots(QDs). CER is a very general principle of experimental physics. Instead of measuring the optical reflectance of the material, the derivative with respect to a modulating electric field is evaluated. This procedure generates sharp, differential-like spectra in the region of interband (intersubband) transitions. We conduct electric-optical studies of both GaAs layers and InAs selfassembled QDs grown by molecular beam epitaxy. Strong GaAsbandgap energy is measured in both structures. In the case of lnAs monolayers in GaAs matrices, the strong GaAsbandgap energy is caused by the lateral quantum confinement.

Methods of Evaluating Efficacy of Hair Growth Following Treatment for Alopecia in Oriental Medicine (한의학적 탈모 치료효과의 객관적 평가 방법)

  • Moon Jung-Bae;Kim Young-Jin;Yi Tae-Hoo
    • The Journal of Korean Medicine
    • /
    • v.27 no.2 s.66
    • /
    • pp.57-69
    • /
    • 2006
  • For decades, scientists and clinicians have examined methods of measuring scalp hair growth. There has been a greater need for reliable, economical and minimally invasive means of measuring hair growth and, specifically, response to Oriental medicine therapy. We review the various methods of measurement described to date, their limitations and value to the clinician. In our opinion, the potential of computer-assisted technology in this field is yet to be maximized and the currently available tools are less than ideal. The most valuable means of measurement at the present time are global photography and phototrichogram-based techniques (with digital image analysis). Subjective scoring systems are also of value in the overall assessment of response to therapy and these are under-utilized and merit further refinement.

  • PDF

The use of topology optimization in the design of truss and frame bridge girders

  • Kutylowski, Ryszard;Rasiak, Bartosz
    • Structural Engineering and Mechanics
    • /
    • v.51 no.1
    • /
    • pp.67-88
    • /
    • 2014
  • It is shown that topology optimization is a valuable tool for the design of bridge girders. This paper is a follow-up to (Kuty${\l}$owski and Rasiak 2014) and it includes an analysis of truss members' outer dimensions dictated by the standards. Moreover, a frame bridge girder mapped from a selected topology is compared with a typical frame girder on the basis of (Kuty${\l}$owski and Rasiak 2014). The analysis shows that topology optimization by means of the proposed algorithm yields a topology from which one can map a frame bridge girder requiring less material for its construction than the typical frame girder currently used in bridge construction.