• 한국결정성장학회지
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• 제13권1호
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• pp.5-14
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• 2003

Principles of a novel pulse growing method are described. The method realized in the crystal growing on a seed from melts under raw melt feeding provided a more reliable control of the crystallization process when producing large alkali halide crystals. The slow natural convection of the melt in the crucible at a constant melt level is intensified by rotating the crucible, while the crystal rotation favors a more symmetrical distribution of thermal stresses over the crystal cross-section. Optimum rotation parameters for the crucible and crystal have been determined. The spatial position oi the solid/liquid phase interface relatively to the melt surface, heaters and the crucible elements are considered. Basing on that consideration, a novel criterion is stated, that is, the immersion extent of the crystallization front (CF) convex toward the melt. When the crystal grows at a <> CF immersion, the raised CF may tear off from the melt partially or completely due to its weight. This results in avoid formation in the crystal. Experimental data on the radial crystal growth speed are discussed. This speed defines the formation of a gas phase layer at the crystal surface. The layer thickness il a function of time a temperature at specific values of pressure in the furnace and the free melt surface dimensions in the gap between the crystal and crucible wall. Analytical expressions have been derived for the impurity component mass transfer at the steady-state growth stage describing two independent processes, the impurity mass transfer along the <> path and its transit along the <> one. The heater (and thus the melt) temperature variation is inherent in any control system. It has been shown that when random temperature changes occur causing its lowering at a rate exceeding $0.5^{\circ}C/min$, a kind of the CF decoration by foreign impurities or by gas bubbles takes place. Short-term temperature changes at one heater or both result in local (i.e., at the front) redistribution of the preset axial growth speed.

• 생물환경조절학회지
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• 제18권4호
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• pp.341-347
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• 2009

본 연구는 수출과채류 시설원예 재배농가의 에너지 절감을 위한 보온자재의 개발을 목표로 수행되었으며 본 보에서는 시설 온실에 사용되어지는 단일 보온자재와 조합형 다겹보온자재에 대해 보온 특성을 조사하기 위하여 실험과 수치해석을 수행하였다. 실험해석의 경우, 실험모듈을 통해 내부 열원의 보온 효과를 조사하기 위해 내 외부의 온도는 K형 열전대와 데이터 획득 장치로 측정하였고, 측정된 온도를 통해 보온자재의 보온특성을 구명하였다. 수치해석은 상용코드인 CFX-11을 이용하였고 다겹보온자재의 내부 공기층은 고려하지 않고 해석하였으며 해석에서 필요한 다겹보온자재의 물성치인 열전도도는 과도 열선법에 의해 측정되는 QTM-500을 사용하였다. 실험 결과, 조합형 보온자재가 단겹 보온자재에 비해 약 45~55%까지 보온율이 높았고, 조합조건에 따라 보온 효과가 달라지기 때문에 보온성이 우수한 조합 조건을 얻을 수 있을 것으로 예상된다. 수치해석 결과와 실험 결과와의 보온율을 비교해 보면 수치해석의 결과가 실험 결과의 보온율에 비해 다소 저하하는 경향을 나타내었는데 이는 다겹보온자재 내부의 공기층을 무시하여 나타난 오차로서 향후 보온자재 내부의 공기층을 고려할 경우 보다 정확한 수치해석 결과를 얻을 수 있을 것이다.

• 한국환경보건학회지
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• 제41권2호
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• pp.61-70
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• 2015

Objectives: The purpose of this research was to examine radon exposure in terms of the relationship between the living environment and indoor radon concentrations among vulnerable households. Methods: Nationwide, 1,129 subjects were selected using personal questionnaires for adequately understanding the living environment, installation of E-PERM radon gas detectors, and investigation of the structure of the housing. Results: The mean concentration of indoor radon for all subjects was $130.2Bq/m^3$ (GM=101.7), and a total of 438 subjects (38.8%) exceeded the recommended standards ($148Bq/m^3$) for public facilities by the Ministry of the Environment. By location, the highest concentrations ($164.3Bq/m^3$, GM=124.1) were seen in North Chungcheong Province. In the case of the Seoul/Gyeonggi Province metropolitan area, they showed $125.6Bq/m^3$ (GM=105.1) and $118.9Bq/m^3$ (GM=96.5), respectively. By type of housing, indoor radon concentrations in single-family housing were higher than in row/multi-family housing (p<0.01). Although indoor radon concentrations raised in accordance with year of construction (p<0.05), the difference between indoor radon concentrations in underground residences was not observed to be statistically significant (p=0.633). Conclusion: More studies are necessary in the future regarding the difference in indoor radon concentrations that may occur due to different of types of indoor construction, building materials, and the amount of building materials.

• 한국환경보건학회지
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• 제46권1호
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• pp.11-21
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• 2020

Objectives: The purpose of this study was to assess the association between pet ownership and asthma symptoms in Korean children. Methods: This study used data from the 8th Panel Study on Korean Children in 2015. For the final study, 1598 cases were used. Wheezing as an asthma symptom was self-reported as an outcome variable. Whether children had owned dogs or cats or not was used as an independent variable. Results: A total of 6.8% of children lived with dogs and 2.1% of children lived with cats in their homes. There were 4.0% of children who had asthma symptoms in the past year. When comparing 'children who had owned dogs for more than 12 months' with 'children who had not owned dogs', the adjusted odds ratio (OR) for 'asthma symptoms' were 1.20 (95% confidence interval (CI), 1.10-1.30) among male children and 2.19 (95% CI, 1.94-2.46) among female children. When comparing 'children who had owned cats for more than 12 months' with 'children who had not owned cats', the adjusted ORs for 'asthma symptoms' were 38.94 (95% CI, 35.55-42.65) among male children and 5.32 (95% CI, 4.60-6.16) among female children. When comparing 'children who had owned both dogs and cats for more than 12 months' with 'children who had not owned at all', the adjusted OR for 'asthma symptoms' was 13.22 (95% CI, 11.93-14.65), and when comparing 'children who had owned cats only' with 'children who had not owned at all', the adjusted OR for 'asthma symptoms' was 9.25 (95% CI, 8.50-10.08). Conclusions: As a result, children's asthma symptoms were higher in the case of cats than with dogs, and in the case of cats, boys were more at risk than girls. In the analysis for the risk of asthma symptoms when a dog and a cat are raised at the same time, it was statistically confirmed that the children in the home were more at risk than with single animal ownership. The results of this study can be considered to be of great importance in policy-making and for the use of educational materials in the field of environmental health.

• 한국강구조학회 논문집
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• 제25권4호
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• pp.431-440
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• 2013

본 연구에서는 HSA800 후판 강재에 적합한 용접재를 선정하고자 표준인장실험을 수행하였다. 본 연구 수행 당시 HSA800 강재에 적용가능한 용접재로 GMAW 용접재(외국산)와 FCAW 용접재(국내산) 두 가지가 추천되어 이들을 사용하였다. 맞댐용접상세와 루트간격을 주요 실험변수로하여 표준인장실험을 통해 용접부의 성능을 평가하였다. 강도에 대한 설계요구조건은 두 용접재 모두 만족하였으나 연성능력 측면에서 GMAW 용접재 보다는 FCAW 용접재가 일관되고 우수한 거동을 보임이 실험적으로 확인되었다. 특히 GMAW 용접재는 용접효율과 작업성의 문제로 현장에서의 상향용접이 어려운 것으로 파악되었다. 같은 완전용입용접이라도 Single bevel보다는 V-groove가 안정적인 구조거동을 보이는 것으로 나타났다. 또한 현행 용접기준의 표준루트 간격을 벗어날 경우 용착의 어려움으로 비정상 파단면이 형성되고 접합성능도 저하됨이 확인되었다. 부분용입용접 접합부의 실험결과에 의할 때 현행 AISC 기준의 부분용입용접부 강도규정은 매우 보수적임이 확인되었다.

• 동의신경정신과학회지
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• 제16권2호
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• pp.13-24
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• 2005

Background and Objectives : Acupuncture as a therapeutic intervention is widely used for the treatment of many functional disorders such as substance abuse and mental dysfunction. Clinical trials are currently underway to determine the effectiveness of acupuncture in the treatment of drug addiction. Yet, there are still many unanswered questions about the basic mechanism of acupuncture. Studies have shown that both the psychomotor stimulant effects and rewarding properties of addictive drugs, including morphine, are sensitized by repeated drug administration and raised the possibility that both of these effects may be linked to the same or closely overlapping the mesolimbic dopamine systems. Neiguan (PC6) point on the pericardium channel which is associated with the brain and its mental function, has been used to treat mental, psychosomatic disorders and gastroenterological disorders. The present study was designed to investigate the effect of acupuncture on repeated morphine-induced changes in extracellular dopamine levels using in vivo microdialysis and to measure the effect of acupuncture on Fos-like immunoreactivity. Methods : Male Sprague-Dawley rats were treated twice a day for three days with increasing doses of morphine (10, 20 and 40 mg/kg, s.c.) or with saline. After 15 days of withdrawal, rats were challenged with morphine hydrochloride (5 mg/kg, s.c.). Acupuncture was applied at bilateral Neiguan (PC6) points for 1 min after the morphine challenge. Results showed that acupuncture at the specific acupoint PC6, but not at control points (tail and HE8) significantly decreased Fos-like immunoreactivity induced by a systemic morphine challenge or a single s.c. morphine injection in the morphine-repeated animals. Results and Conclusions : These results suggest that reduction in sensitization may be one mechanism whereby acupuncture alleviates morphine craving in addicts. Moreover, in a more general sense these results suggest that acupuncture can be used as a therapeutic intervention for correcting reversible malfunction of the body by direction of brain pathway and thus acupuncture can contribute to the biochemical balance in the central nervous system by regulating neurotransmitters.

• KEPCO Journal on Electric Power and Energy
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• 제5권4호
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• pp.257-262
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• 2019

Lattice steel towers for overhead transmission lines have been replaced by tubular steel poles due to the visual impact of large and complex shape of truss type. Demand for tubular steel poles consisting of a single frame member continues to grow because of its advantages such as visual minimization, architectural appeal and minimal site consumptions. However, there are some constraints on the transportation and construction. As the diameter of tower base has been enlarged, it may exceed minimum height limit required to pass the tunnel in case of land transportation. Also, in a narrow place where it is not easy to secure the installation areas such as mountainous places, there might be some areas wherein it must secure a wide working space so that large vehicles and working cranes will be allowed to enter. In this paper, we presented a vertical separated tubular steel pole, which is a new type of support that can be implemented for general purpose such as mountainous areas or narrow areas to improve the issues raised by breaking away from the conventional design and fabrication methods. Technical approaches for overcoming the limit of the cross-sectional size is to separate and modularize the cross-section of the tubular steel pole designed with a size that cannot be carried or assembled, and to lighten it with a weight capable of being transported and assembled in a narrow space or mountainous area. As a result of this research, it will be possible to enter small and medium sized vehicles in locations where it is restricted to transport by large-sized vehicles. In the case of mountainous areas, it will be possible to divide it into a weight capable of being carried by a helicopter and it will be easy to adjust and fabricate it with individual modules. Furthermore, in order to break away from the traditional construction method, we proposed the equipment that can be applied to the assembly of Tubular Steel Pole without using a large crane in locations where there is no accessible road or in locations wherein large cranes cannot enter. In particular, this paper shows the movable assembling equipment and some methods that are specialized for vertical separated tubular steel pole consisting of members with reduced weight. The proposed assembly equipment is a device for assembling the body of the Tubular Steel Poles. It will be installed inside the support and the modules can be lifted by using the support itself.

• 한국의사학회지
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• 제24권2호
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• pp.25-55
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• 2011

The currently existing "Bonchojeonghwa (本草精華)" is a manuscript without the preface and the epilogue, composed of 2 books in 2 volumes. This book is a quintessence of knowledge on science of medicinal ingredients (medicinal phytology I herbal science) as well as an trial of new development in Chosun medical science. I.e. this book includes surprising change representing medical science in Chosun dynasty as a single publication on science of medicinal ingredients. It holds a value essential to clinician as a specialized book in medicinal ingredients, and Includes richer content on medicinal ingredients than any other books published before. In addition, it is away from boring list-up of superfluous knowledge as seen in "Bonchokangmok(本草綱目)" published in China, and well summarizes essential knowledge which can be used within a range of medicines available in Korea. This book has an outstanding structure that can be even used in today's textbook on science of medicinal ingredients, as it has clear theory, system and classification. Because it handles essential learning points prior to prescription to disease, it is possible to configure new prescription and adjustment of medicinal materials. Moreover, this book can play a good role for linguistic study at the time of publication, because it describes many drugs in Hangul in many parts of the book. "Bonchojeonghwa" includes a variety of animals, plants and mineral resources in Korea, like "Bonchokangmok" which was recently listed in UNESCO. As such, it has a significance in natural history as well as pharmacy in Korean Medicine. It has various academic relationships all in biologic & abiologic aspects. It has importance in sharing future biological resources, building up international potential, setting up the standard for biologic species under IMF system, and becoming a base for resource diplomacy. We should not only see it as a book on medicinal ingredients in terms of Oriental Medicine, but also make an prudent approach to it in terms of study strengthening Korea's national competitiveness. After bibliographical reviewing on the features & characteristics of the only existing copy of "Bonchojeonghwa" housed in Kyujanggak(奎章閣) of Seoul National University, the followings are noted. First, "Bonchojeonghwa" is a specialized book on medicinal ingredients voluntarily made by private hands to distribute knowledge on drugs in the desolate situation after Imjinoeran (Japanese Invasion in 1592), without waiting for governmental help. Second, it raised accessibility and practicality by new editing. Third, it classified 990 different kinds of drugs into plant, animal, and mineral at large, and dassified more in detail into 15 'Bu' and 48 'Ryu' at 258 pages. Fourth, the publication of this book is estimated to be around 1625~1633, at the time of Injo's reign in 17th century. Fifth, it contains the existing & up-to-date knowledge at the time of publication, and it is possible to see the supply-demand situation by Hangul descriptions in 149 places in the book. By the fact that there are many linguistic evidences of 17th century, explains well when the book was published.

• 한국잡초학회지
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• 제32권3호
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• pp.174-179
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• 2012

한국잔디로 조성된 국내 골프코스에서 한지형잔디의 사용증가로 이종잔디의 혼입이 증가하고 있다. 본 연구에서는 전국 50곳의 골프코스들을 조사하여 이종잔디 식재와 혼입 현황을 파악하였다. 조사한 골프코스들 중에서 이종잔디가 1 종류 이상 혼입된 곳은 47곳으로 나타났으므로, 이종잔디의 혼입 문제는 전국 거의 모든 골프코스에서 발생하는 것으로 사료되었다. 이종잔디의 혼입은 한국잔디에서 크리핑벤트그래스와 켄터키블루그래스의 혼입 가능성이 있는 37곳 중 각각 25곳과 33곳, 켄터키블루그래스에서 크리핑벤트그래스의 혼입 가능성이 있는 47곳 중 43곳에서 발생하였다. 한편, 이종잔디의 혼입(한국잔디에 크리핑벤트그래스의 혼입, 한국잔디에 켄터키블루그래스의 혼입, 또는 켄터키블루그래스에 크리핑벤트그래스의 혼입)이 발생한 골프클럽 중 한 종류의 혼입이 나타난 곳은 14곳, 두 종류가 나타난 곳은 12곳, 세 종류 모두가 나타난 곳은 21곳이었다.

• Asian-Australasian Journal of Animal Sciences
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• 제29권9호
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• pp.1215-1221
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• 2016

The prediction of carcass composition in Hanwoo steers is very important for value-based marketing, and the improvement of prediction accuracy and precision can be achieved through the analyses of independent variables using a prediction equation with a sufficient dataset. The present study was conducted to develop a prediction equation for Hanwoo carcass composition for which data was collected from 7,907 Hanwoo steers raised at a private farm in Gangwon Province, South Korea, and slaughtered in the period between January 2009 and September 2014. Carcass traits such as carcass weight (CWT), back fat thickness (BFT), eye-muscle area (EMA), and marbling score (MAR) were used as independent variables for the development of a prediction equation for carcass composition, such as retail cut weight and percentage (RC, and %RC, respectively), trimmed fat weight and percentage (FAT, and %FAT, respectively), and separated bone weight and percentage (BONE, and %BONE), and its feasibility for practical use was evaluated using the estimated retail yield percentage (ELP) currently used in Korea. The equations were functions of all the variables, and the significance was estimated via stepwise regression analyses. Further, the model equations were verified by means of the residual standard deviation and the coefficient of determination ($R^2$) between the predicted and observed values. As the results of stepwise analyses, CWT was the most important single variable in the equation for RC and FAT, and BFT was the most important variable for the equation of %RC and %FAT. The precision and accuracy of three variable equation consisting CWT, BFT, and EMA were very similar to those of four variable equation that included all for independent variables (CWT, BFT, EMA, and MAR) in RC and FAT, while the three variable equations provided a more accurate prediction for %RC. Consequently, the three-variable equation might be more appropriate for practical use than the four-variable equation based on its easy and cost-effective measurement. However, a relatively high average difference for the ELP in absolute value implies a revision of the official equation may be required, although the current official equation for predicting RC with three variables is still valid.