• Title/Summary/Keyword: hot plate methods

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A Study on Effective Relations between China's Cancellation of the Export Rebate of VAT tax and Chinese Steel Export to Korea. (중국의 수출 증치세 환급 취소가 중국산 철강재의 대한국 수출에 미치는 영향)

  • Lee, Seoung Taek
    • International Commerce and Information Review
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    • v.19 no.3
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    • pp.83-105
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    • 2017
  • I tried to analyze export relation of influence in Chinese H beam(common steel), Hot Rolled Steel(common steel), Plate(common steel) which could be influenced immediately by China's cancellation of the export rebate of value added tax in 2010 through the statistic methods such as cointegration, Granger causality, impulse response and variance decomposition. In the first period they mutually influenced each other in export to Korea but in the second period, this relation of influence was lessoned. Due to production expansion of Hot Rolled Steel(common steel), Plate(common steel) in Korea, the change of import trend, the market change of steel users' industries and China's expedient export of boron steel to Korea, mutual influence among these products was greatly declined. Ever since Hyundai Steel's production expansion involving blast furnace facilities, there is need for the industry to concentrate on developing new markets for its facilities' output in Korea. Therefore, Korea's steel industry desperately needs strength of de-jure standards such as unique quality standards and related certifications, efficient distribution management, as well as export promotion strategy through its global trading network to effectively address its structural supply-demand imbalances.

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Screening on Biological Activities of the Extracts from Fruit and Stem of Prickly Pear(Opuntia ficus-indica var. saboten) (손바닥 선인장 열매 및 줄기 추출물의 생리활성(I)-일반약리검색)

  • Lee, Chung-Kyu;Lee, Young-Chul;Moon, Young-In;Park, Hee-Juhn;Han, Yong-Nam;Choi, Jong-Won
    • Korean Journal of Pharmacognosy
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    • v.32 no.4 s.127
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    • pp.330-337
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    • 2001
  • Prickly pear(Opuntia ficus-indica var. saboten Makino, Cactaceae) is a tropical or subtropical plant, which is widely used as folk medicine for burned wound, edema and indigestion. Screening on the biological properties of the fruits(OFS-Fr) and stems(OFS-St) of the plant was carried out to prove the pharmacological significance. By hot plate and acetic acid-inducing writhing methods, significant analgesic effects of OFS-Fr and OFS-St were found in mice and anti-edemic effect was observed in carrageenin-induced inflammatory rats. However, the extracts showed no significant actions on central and autonomic nervous system and blood circulatory system, which imply no toxic effects to animal.

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Characterization of Soldering Property on Heating Condition by Infrared Lamp Soldering Process for C-Si Photovoltaic Modules (적외선 램프 가열방식을 이용한 태양전지 셀의 솔더링 공정 및 열처리 조건 별 특성 평가)

  • Son, Hyoun Jin;Lee, Jung Jin;Kim, Sung Hyun
    • Current Photovoltaic Research
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    • v.4 no.2
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    • pp.59-63
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    • 2016
  • A key point of a soldering process for photovoltaic (PV) modules is to increase an adhesive strength leading a low resistivity between ribbon and cell. In this study, we intended to optimize a heating condition for the soldering process and characterize the soldered joint via physical and chemical analysis methods. For the purpose, the heating conditions were adjusted by IR lamp power, heating time and hot plate temperature for preheating a cell. Since then the peel test for the ribbon and cell was conducted, consequently the peel strength data shows that there is some optimum soldering condition. In here, we observed that the peel strength was modified by increasing the heating condition. Such a soldering property is affected by a various factors of which the soldered joint, flux and bus bar of the cell are changed on the heating condition. Therefore, we tried to reveal causes determining the soldering property through analyzing the soldered interface.

Anti-Rheumatoid Arthritis Effect of the Kochia scoparia Fruits and Activity Comparison of Momordin Ic, its Prosapogenin and Sapogenin

  • Choi, Jongwon;Lee, Kyung-Tae;Jung, Hyun-Ju;Park, Hee-Sun;Park, Hee-Juhn
    • Archives of Pharmacal Research
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    • v.25 no.3
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    • pp.336-342
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    • 2002
  • MeOH extract of Kochia scoparia was fractionated into $CHCl_3-$, EtOAc- and BuOH extracts and the last fraction were hydrolyzed by 3%-NaOH ($MeOH-H_2O$) to compare the bioactivities on antinociceptive and anti-inflammatory effects. Silica gel column chromatography of BuOH fraction afforded a large amount of $3-Ο-{\beta}-D-xylopyranosyl {\;}(1{\rightarrow}3)-{\beta}-D-glucuronopyranosyl$ oleanolic acid (momordin Ic, 4) and that of acid hydrolysate of BuOH fraction gave $3-Ο-{\beta}-D-glucuronopyranosyl oleanolic$ acid (momordin Ib, 3), its 6'-Ο-methyl ester (2) and oleanolic acid (1). Silica gel column chromatography of alkaline hydrolysate afforded a large amount of 4. MeOH extract and both EtOAc- and BuOH fractions were active in the rheumatoidal rat induced Freund's complete adjuvant reagent (FCA) whereas $CHCl_3$ fraction was inactive. Compound 1 and 4 showed significant activities in the same assay but oleanolic acid 3-Ο-glucuronopyranoside (3) showed no activity. These fashions were also observed in carrageenan-induced edema of the rat and in the antinociceptive activity tests undertaken in hot plate- and writhing methods. These results suggest that momordin Ic and its aglycone, oleanolic acid, could be active principles for rheumatoid arthritis.

Numerical analysis of steady and transient processes in a directional solidification system

  • Lin, Ting-Kang;Lin, Chung-Hao;Chen, Ching-Yao
    • Coupled systems mechanics
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    • v.5 no.4
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    • pp.341-353
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    • 2016
  • Manufactures of multi-crystalline silicon ingots by means of the directional solidification system (DSS) is important to the solar photovoltaic (PV) cell industry. The quality of the ingots, including the grain size and morphology, is highly related to the shape of the crystal-melt interface during the crystal growth process. We performed numerical simulations to analyze the thermo-fluid field and the shape of the crystal-melt interface both for steady conditions and transient processes. The steady simulations are first validated and then applied to improve the hot zone design in the furnace. The numerical results reveal that, an additional guiding plate weakens the strength of vortex and improves the desired profile of the crystal-melt interface. Based on the steady solutions at an early stage, detailed transient processes of crystal growth can be simulated. Accuracy of the results is supported by comparing the evolutions of crystal heights with the experimental measurements. The excellent agreements demonstrate the applicability of the present numerical methods in simulating a practical and complex system of directional solidification system.

Fabrication of CIGS Thin Film Solar Cell by Non-Vacuum Nanoparticle Deposition Technique (비진공 나노입자 코팅법을 이용한 CIGS 박막 태양전지 제조)

  • Ahn, Se-Jin;Kim, Ki-Hyun;Yoon, Kyung-Hoon
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.06a
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    • pp.222-224
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    • 2006
  • A non-vacuum process for $Cu(In,Ga)Se_2$ (CIGS) thin film solar cells from nanoparticle precursors was described in this work CIGS nanoparticle precursors was prepared by a low temperature colloidal route by reacting the starting materials $(CuI,\;InI_3,\;GaI_3\;and\;Na_2Se)$ in organic solvents, by which fine CIGS nanoparticles of about 20nm in diameter were obtained. The nanoparticle precursors were mixed with organic binder material for the rheology of the mixture to be adjusted for the doctor blade method. After depositing the mixture of CIGS with binder on Mo/glass substrate, the samples were preheated on the hot plate in air to evaporate remaining solvents ud to burn the organic binder material. Subsequently, the resultant (porous) CIGS/Mo/glass simple was selenized in a two-zone Rapid Thermal Process (RTP) furnace in order to get a solar ceil applicable dense CIGS absorber layer. Complete solar cell structure was obtained by depositing. The other layers including CdS buffer layer, ZnO window layer and Al electrodes by conventional methods. The resultant solar cell showed a conversion efficiency of 0.5%.

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Anthelmintic and Analgesic Activities of Trachyspermum Khasianum H. Wolff

  • Sutnga, Innocent;Marbaniang, Balari;Hazarika, Gautom;Goswami, Priyanka;Choudhury, Ananta
    • Journal of Pharmacopuncture
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    • v.23 no.4
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    • pp.230-236
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    • 2020
  • Objectives: Trachyspermum khasianum H. Wolff is a rare medicinal plant characteristically used by the traditional healers in traditional medicine for the treatment of throat-pain, toothache, and stomach ache. The study was designed to determine the anthelmintic and analgesic properties of the aerial parts of Trachyspermum khasianum H. Wolff (Family: Apiaceae). The aqueous and ethanol extract of T. khasianum H. Wolff was prepared and subjected for evaluation to determine the possible therapeutic effects. Methods: Anthelmintic activities of the extracts were determined by observing the time taken to paralyze and the time taken for the death of earthworms (Eisenia foetida) as compared to the standard drug-Albendazole (20 mg/ml) and control. Analgesic potential of the extracts was evaluated using Eddy's hot plate method to understand the analgesic activity in rats (Wistar rats) at 100 mg/kg and 200 mg/kg body weight doses and compared with the standard reference (Diclofenac sodium: 10 mg/kg of animals). Results: The extracts showed a significant dose-dependent anthelmintic effect at the different concentrations (10, 20, and 40) mg/ml, compared to that of the standard drug (20 mg/ml). Also, the results suggested that the plant extracts possess significantly analgesic activity in rats. Conclusion: The studies indicate that Trachyspermum khasianum shows anthelmintic and potent analgesic activities. Further research should be carried out to identify the specific phytoconstituents responsible for both analgesic and anthelmintic activities and its possible mechanism of action.

Pasteurization Efficiency and Physico-chemical Changes of Soymilk HTST Pasteurized Using Microwaves (두유의 마이크로파 고온단시간 살균시 살균효과 및 이화학적 성분 변화)

  • Kim, Suk-Shin;Lee, Joo-Hee
    • Korean Journal of Food Science and Technology
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    • v.31 no.5
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    • pp.1196-1202
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    • 1999
  • This work was to determine the microbial and physico-chemical changes of HTST-pasteurized soymilk using microwave energy. Soymilk was HTST pasteurized$(at\;90^{\circ}C\;for\;20\;sec)$ by three methods: by heating in a stainless steel tube immersed in a hot water bath(MP0), by heating in a microwave cavity to a defiled temperature and then holding in a hot water bath(MP1), and by both heating and holding in a microwave cavity(MP2). The microbial quality based on the total plate count was in the order of MP0, MP2 and MP1. The three samples pasteurized by different methods showed the similar microbial quality with respect to the coliform count, psychrotrophic bacterial count and phosphatase activity. The destruction of trypsin inhibitor was in the order of MP0, MP1 and MP2. There were no significant differences in pH, titratable acidity, viscosity and vitamin $B_2$ content before and after pasteurization and among the different pasteurization methods. The similar or higher quality retention of the MP1 or MP2 supports the possibility of using microwave energy for the HTST pasteurization of soymilk and other fluid food products.

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Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016 (설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

Development on New Laser Tabbing Process for Modulation of Thin Solar Cell (박형 태양 전지 모듈화를 위한 레이져 태빙 자동화 공정(장비) 개발)

  • No, Donghun;Choi, Chul-June;Cho, Hyun Young;Yu, Jae Min;Kim, JungKeun
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.58.1-58.1
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    • 2010
  • In solar cell module manufacturing, single solar cells has to be joined electrically to strings. Copper stripes coated with tin-silver-copper alloy are joined on screen printed silver of solar cells which is called busbar. The bus bar collects the electrons generated in solar cell and it is connected to the next cell in the conventional module manufacturing by a metal stringer using conventional hot air or infrared lamp soldering systems. For thin solar cells, both soldering methods have disadvantages, which heats up the whole cell to high temperatures. Because of the different thermal expansion coefficient, mechanical stresses are induced in the solar cell. Recently, the trend of solar cell is toward thinner thickness below 180um and thus the risk of breakage of solar cells is increasing. This has led to the demand for new joining processes with high productivity and reduced error rates. In our project, we have developed a new method to solder solar cells with a laser heating source. The soldering process using diode laser with wavelength of 980nm was examined. The diode laser used has a maximum power of 60W and a scanner system is used to solder dimension of 6" solar cell and the beam travel speed is optimized. For clamping copper stripe to solar cell, zirconia(ZrO)coated iron pin-spring system is used to clamp both joining parts during a scanner system is traveled. The hot plate temperature that solar cell is positioned during lasersoldering process is optimized. Also, conventional solder joints after $180^{\circ}C$ peel tests are compared to the laser soldering methods. Microstructures in welded zone shows that the diffusion zone between solar cell and metal stripes is better formed than inIR soldering method. It is analyzed that the laser solder joints show no damages to the silicon wafer and no cracks beneath the contact. Peel strength between 4N and 5N are measured, with much shorter joining time than IR solder joints and it is shown that the use of laser soldering reduced the degree of bending of solar cell much less than IR soldering.

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