• Nuclear Engineering and Technology
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• 제49권8호
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• pp.1748-1751
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• 2017

Reduced activation ferritic/martensitic (RAFM) steels are widely applied as structural materials in the nuclear industry. To investigate hydrogen's effect on RAFM steels' elastic properties and the mechanism of that effect, a procedure of first principles simulation combined with experiment was designed. Density functional theory models were established to simulate RAFM steels' elastic status before and after hydrogen's insertion. Also, experiment was designed to measure the Young's modulus of RAFM steel samples with and without hydrogen charging. Both simulation and experiment showed that the solubility of hydrogen in RAFM steels would decrease the Young's modulus. The effect of hydrogen on RAFM steels' Young's modulus was more significant in water-quenched steels than it was in tempering steels. This indicated that defects inside martensite, considered to be hydrogen traps, could decrease the cohesive energy of the matrix and lead to a decrease of the Young's modulus after hydrogen insertion.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.593-597
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• 2002

The paper introduces a research on the W-band Millimeter Wave Radiometer(RADW92) through an airborne experiment. Microwave remote sensing images of part of the Yellow River and the WeiHe River are of fared. Analysis of factors influencing the image qualities as well as the resolutions to them are also included. The RADW92 is the first generation of Millimeter Wave Radiometer in China, which works with operating frequency 92 GHz, the bandwidth 2 GHz, the integration time 60ms, the system sensitivity 0.6k and the linearity better than 0.999. Cassegrain Antenna is designed for imaging by conically scanning. The result of the experiment suggested that RADW92 had been adequate for space use.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• 제22권1호
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• pp.1.2-5
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• 1994

Ionospheric sounding experiments have been conducted at RRL (Radio Research Laboratory), Ministry of Communications, using Digisonde 256 since its installation in 1990. Routine observations of the vertical sounding are carried out 48 times (or 39 times) a day, at every 24 hour. In addition, we also made oblique sounding experiments to obtain the real time data of Maximum Usable Frequency (MUF) and detect the anomalous HF propagation, as a part of the joint study between RRL and CRL (Communications Research Laboratory) of Japan. The two stations involved in the study were Anyang (RRL, Korea) and Kokubunji (CRL, Japan). The ionosondes used in both stations were Digisonde 256, developed by ULCAR (University of Lowell, Center for Atmospheric Research), U. S. A. , and the synchronization of time was accomplished with the help of GPS receiver. During most part of the experiments RRL transmitted non-modulated pulses, and CRL received them. The experiment was scheduled from October 25 through October 29, 1993. However, the ionosphere was not developed well enough to conduct the experiment with pre-set operation parameters. The experiment became successful (from 0500 UT to 0800 UT, October 29) only after the operation parameters had been changed, and the continuous ionograms were obtained by CRL at 0718 UT and 0733 UT in October 29, 1993. We believe this type of experiment will ensure the qualitative enhancement of solar-terrestrial physics research and a routine observation of the oblique ionospheric sounding. In this report, we present the results of the fore-mentioned oblique sounding as well as the vertical sounding results obtained by Digisonde 256 at Anyang station of RRL.

• 한국산학기술학회논문지
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• 제8권2호
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• pp.324-332
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• 2007

본 연구에서는 원격 실험실에서 사용될 수동소자인 저항, 인덕터, 캐패시터의 소자값을 원격으로 제어할 수 있는 소자를 개발하였으며, 이 소자를 이용한 회로이론 원격 실험실을 구현하였으며, 원격제어용 수동소자 R, L, C를 사용한 RLC 직렬회로 원격실험실의 예로 실험의 효용성을 보였다. 따라서 제안한 원격 실험실을 통해 학생들은 원격으로 다양한 소자값을 변경시켜가면서 실제 실험을 수행할 수 있게 되므로, 가상실험실이 안고 있는 실제 실험값을 얻을 수 없는 문제점을 해결할 수 있으며, 특히 학생 개개인이 실험할 수 없는 어떤 환경에서도 실험을 할 수 있는 환경을 제시하였다.

• 한국과학교육학회지
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• 제27권1호
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• pp.59-69
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• 2007

이 연구에서는 과학실험의 새로운 방법으로 학교현장에서 도입 단계에 있는 컴퓨터를 기반으로 하는 MBL실험에 대하여 초 중 고 교사들의 인식을 조사하였다. 이를 위해 초 중 고등학교의 과학교과서에 나오는 실험 주제 중 MBL(microcomputer based laboratory) 실험으로 대체할 수 있는 실험주제를 세 가지씩 선정 하여 초 중 고등학교 과학 교사들에게 연수를 실시한 후 MBL실험 연수 내용 MBL실험기대효과 연수 후 MBL실험 적용 의지에 대하여 설문조사를 실시하였다 연구 결과, 초 중 고등학교 교사 모두 MBL실험 연수가 매우 유익하고 유용하다고 생각하였으나 연수내용 수준에 대하여 약간 높게 생각하였다. 또한 MBL실험에 대한 기대효과로는 컴퓨터를 이용하는 MBL실험은 정확하고 빠르게 데이터를 수집하고 처리 할 수 있어 실험 시간을 단축할 수 있으며, 단축된 실험시간을 실험결과를 분석하고 토론하는 활동에 활용할 수 있어서 올바른 개념 형성과 그래프 해석 능력 및 탐구력 신장에 효과적일 것이라고 생각하였다. 그러나 실험기구 조작 능력 향상에는 효과적이라고 생각하지 않았다. 또한 대부분의 교사들은 연수 후에 과학실험 수업에 바로 이용하려는 의지가 높게 나타났으나, 새로운 교육과정에 도입하기 위해서는 MBL실험을 위한 도구 구입과 낙후된 실험실 여건, 교사 연수 기회 부족 등이 장애라고 지적하였다. MBL실험의 확장 적용을 위해서는 MBL실험 도구의 단가를 낮추기 위한 기술 개발 및 각종 센서의 제작 보급과 함께 MBL실험 자료 개발과 교사연수가 확대되어야 할 것이다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권7호
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• pp.1003-1011
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• 2013

Two experiments were conducted to determine the effects of different dietary lysine levels on the apparent nutrient digestibility, the serum amino acid (AA) concentration, and the biochemical parameters of the precaval and portal vein blood in growing pigs. In Experiment 1, 15 noncannulated pigs received diets with different lysine densities (0.65%, 0.95%, and 1.25% lysine) for 13 d. A total collection digestion test was performed, and blood samples were collected from the precaval vein at the end of the experiment. In Experiment 2, four cannulated pigs were fed the same diets of Experiment 1. The experiment used a self-control experimental design and was divided into three periods. On d 5 of each period, at 0.5 h before feeding and hourly up to 8 h after feeding, single blood samples were collected from catheters placed in the portal vein. In Experiment 1, some serum AAs (including lysine), serum urinary nitrogen (SUN), and total protein (TP) concentrations were significantly affected by the dietary lysine levels (p<0.05). Moreover, the 0.65% lysine treatment showed a significant lower apparent digestibility of gross energy, dry matter, crude protein, and phosphorus than the other treatments (p<0.05). In Experiment 2, serum lysine, histidine, phenylalanine, threonine, valine, isoleucine (p = 0.0588), triglyceride, and SUN (p = 0.0572) concentrations were significantly affected by the dietary lysine levels (p<0.05). Additionally, almost all of the determined serum AA and total AA concentrations reached their lowest values at 0.5 h before feeding and their highest values at 2 h after feeding (p<0.05). These findings indicate that the greatest absorption of AA occurred at 2 h after feeding and that the dynamic profile of serum AA is affected by the dietary lysine levels. Moreover, when the dietary lysine content was 0.95%, the growing pigs achieved a better nutrient digestibility and serum metabolites levels.

• 한국산업보건학회지
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• 제20권4호
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• pp.248-255
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• 2010

Airborne nanoparticle concentrations in three metrics (particle surface area concentration, particle number concentration, and particle mass concentrations) were measured by task in a laboratory making carbon nanotubes (CNTs) films using three direct reading instruments. Because of the conducted other researcher's experiment before the tasks, airborne nanoparticle surface area and number concentrations are the highest at the first time conducted weighing and mixing by sonication task, respectively. Because of the mist generated during mixing by sonication, the highest airborne nanoparticle surface area and PM1 concentrations were measured in the task among the total. Nanoparticle surface area concentrations at the researchers' breathing zones had high correlation (r=0.93, p<0.01) with those measured at an area in the laboratory. This result indicates that nanoparticles generated during the experiment contaminated the whole room air. When the experiment performed all the fume hoods weren't operated and making CNTs films task were conducted in the out of the fume hoods. In conclusion, researchers performing making CNTs film experiments were exposed to airborne nanoparticles generated during the experiment without adequate controls. We recommend that adequate controls should be implemented so that workers' exposures to airborne nanoparticle are limited to minimum levels.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1343-1345
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• 2003

An internal wave observation experiment by SAR in South China Sea is described. Two scenes of Radarsat ScanSAR images were acquired. Internal solitary waves are found in all the two images. It is concluded that these internal waves are generated in Bashi channel. Relationship between internal wave generation and tide is studied based on analyzing of tidal data of Legaspi in Philippine. Using ocean environmental data of this sea area internal waves’ amplitude and wave speed are detected by SAR images.

• 대한안전경영과학회지
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• 제19권4호
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• pp.133-140
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• 2017

The Ministry of Science, ICT and Future Planning made law for Pre-Hazard Risk Analysis in December 31, 2014 to protect researchers from continuing accidents in laboratory. Conducted before an experiment, Pre-Hazard Risk Analysis finds hazards of the experiment and rules to manage the hazards.So the Pre-Hazard Risk Analysis can support laboratory safety system by prevent accidents in laboratory. Pre-Hazards Risk Analysis is newly created system so that executors need Guidelines to perform this analysis properly. This study is to develop guide tool for Pre-Hazard Risk Analysis by analyzing other risk assessment systems; PSM, Off-site Consequence Assessment, laboratory safety system. Also, this study suggested how to establish database for Pre-Hazard Risk Assessment by analyse KRAS.

• Asian-Australasian Journal of Animal Sciences
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• 제33권5호
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• pp.802-811
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• 2020

Objective: Two experiments were conducted to investigate the effects of dietary sucralose on diet preference and growth performance of weaned piglets, and a third experiment was a 28-d safety study to examine if high-dose sucralose could affect the health state of weaned piglets. Methods: In experiment one, 48 piglets had free access to a corn-soybean based diet and the same diet supplemented with 150 mg/kg sucralose for 15 d. In experiment two, 180 piglets were blocked into 5 treatments with 6 replications. They were fed basal diets supplemented with 0, 75, 150, 225, and 300 mg/kg sucralose for 28 days. In experiment three, 108 piglets were randomly assigned to 3 treatments and fed diets supplemented with 0, 150 (suitable level), and 1,500 (ten-fold suitable level) mg/kg sucralose for 28 d. Results: The experiment 1 showed that piglets preferred (p<0.05) diets containing sucralose during experimental period. In experiment 2, piglets fed a diet supplemented with 150 mg/kg sucralose had a higher average daily gain (ADG) and average daily feed intake (ADFI) than pigs in the control group and other treatment groups during the experiment period. The concentrations of sucralose over 150 mg/kg may decrease feed intake. However, no difference in feed conversion ratio was observed. In experiment 3, piglets fed diet supplemented with 150 mg/kg sucralose had a higher ADG and ADFI than that of pigs in the control group and 1,500 mg/kg treatment groups during the experiment period. Clinical blood metabolites, organ index and histological morphology were not significantly different between sucralose treatments. Conclusion: Sucralose can promote feed intake and thereby improve growth performance of weaned piglets. Moreover, inclusion of 1,500 mg/kg sucralose was demonstrated to have no observed adverse effects. Supplementing 150 mg/kg sucralose for weaned piglets is recommended in this study.