• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.9
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• pp.895-900
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• 2012

This paper aims to examine the effect of nanodroplets on pool-type absorption heat transfer enhancement and to find the relationship between the dispersion stability and the absorption performance. The concentrations of oil and surfactant are considered as the key parameters. $C_{12}E_4$ and Tween20 are used as the surfactants and N-decane oil is added to the $NH_3/H_2O$ solution to make the binary nanoemulsion fluids. Binary nanoemulsion fluids are dispersed by the ultrasonic vibrator and the stirrer under specific conditions. The dispersion stability of binary nanoemulsion fluids for each oil concentrations is evaluated from the droplet size and Tyndall effect analysis. The absorption performance of binary nanoemulsion fluids is compared with the result of dispersion stability. In addition, it is found that the binary nanoemulsion fluid is a strong candidate as a new working fluid for absorption applications.

• Asian Journal of Turfgrass Science
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• v.23 no.1
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• pp.123-132
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• 2009

This study was designed to investigate the effect of the late fall fertilization applied with methyl urea(MU), compound chemical fertilizer(CF), humate(HM), and organic compost fertilizer(NS) on spring greenup of creeping bentgrass at following year. The plots were treated with various snow cover periods before transforming to ski slopes from golf holes during 2007 fall to 2008 spring. The highest visual quality and greenup rate were shown on MU or HM applications at 10 days before snow cover treatment. The CF treatment which had a highest phosphorus rate was most effective with a 13 cm of root length at the reconversion date to golf hole from ski slope of the following spring. However, the application of CF followed by immediate snow cover showed the worst results on visual quality and green color caused by a leaf burning damage from the residual effect of CF. At least 10 days were required to avoid phytotoxicant from undissolved granular of CF before snow cover practise. The application of NS showed the highest result on leaf dry weight at no snow cover plot in next spring, but not on green color and visual quality. Therefore, the proper interval period of snow cover after late fall fertilization should be an important management skill on the spring greenup of creeping bentgrass on following year transforming from ski slope to golf hole.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.334-341
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• 2004

Polysaccharides were prepared from Orostachys japonicus by extration with hot steam water (OJPl). The OIPl fraction was further purified by Sephadex G-50 gel filtration chromatography to produce FI (polysaccharides) and FII (oligosaccharides) fraction. The average molecular masses o fFI and FII fraction were determined to be 3050 kDa and 13 kDa, respectively. The antimicrobial activity of OIPl was tested against 8 strains of bacteria and one strain of yeast by the disc diffusion method, fluorescein diacetate (FDA) method and broth dilution method. The OIPl exhibited a very strong growth inhibition to Candida albicans. The OIPl remarkably sup­pressed the growth of Salmonella typhimurium and Staphylococcus aureus. The OIPl showed higher growth inhibition to Escherichia coli and Pseudomonas aeruginosa than propolis, positive control. When the anticancer activity of the OIPl, FI or FII was examined against human cancer cell lines and the Sarcoma 180 cells, these widely suppressed the proliferation of cell lines in the MTT assay and morphology study. Especially, they remarkably inhibited the growth of A549, HeLa and AGS cells. Also treatment of cancer cells with OJPl, FI or FII induced apoptotic cell death characterized by DNA fragmentation. The OJPl, FI or FII exhibiting various biological activities such as antimicrobial activity and anticancer activity is expected to be developed as new biohealth products.

• Management & Information Systems Review
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• v.34 no.3
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• pp.303-315
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• 2015

The objective of this study was to devise and empirically validate a model in which personal characteristic, infrastructure of business start-up, difficulties of business start-up influence the intention of business start-up. The research model was analyzed by the structural equation modeling(SEM) technique, supported by SAS 9.13 and SMART-PLS 2.0. The results of this study can be summarized as follows. The results of this study can be summarized as follows. Firstly, personal characteristic had a significant impact on intention of business start-up. Secondly, infrastructure of business start-up also had a significant impact on intention of business start-up. Lastly, on the other hand, difficulties of business start-up had no direct impacts on intention of business start-up.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.559-559
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• 2013

KSTAR (Korea Superconducting Tokamak Advanced Research) 장치는 차세대 에너지원 중의 하나인 핵융합로를 위한 과학기술 기반을 마련하기 위해 개발된 중형급 토카막 실험장치로서 토카막 운전 영역의 확장과 안정성 확보, 정상상태 운전 도달을 위한 방법 연구, 최적화된 플라즈마 상태와 연속 운전 실현 등을 주요 목표로 하고 있다. 이를 위해 핵융합 반응에 의한 점화조건과 가까운 상태로 플라즈마를 가열해주어야 하며, 토카막 장치의 저항가열 이외에도 외부에서 추가 가열이 반드시 필요하다. 중성 입자빔 입사 장치는 현재 토카막에서 사용되고 있는 가열장치 중 가장 신뢰성있는 추가 가열 장치라 할 수 있으며 한국 원자력연구원에서는 1997년부터 KSTAR 토카막 실험 장치에 사용될 중성 입자빔 입사 장치를 개발해왔었다. 중성빔 입사 장치는 크게 이온원, 진공함, 열량계, 진공 펌프, 중성화 장치, 이온덤프와 전자석으로 이루어져 있으며, 이중 이온원은 중성빔의 성능을 좌우하는 핵심적인 장치라 할 수 있다. 최근 한국원자력연구원에서는 2 MW 중성 입자빔 입사장치용 이온원 개발을 완료하여 KSTAR 토카막 장치에 설치하였으며, 2013년 현재 KSTAR에는 총 두 개의 이온원이 장착되어 최대 약 3 MW 이상의 중수소 중성 입자빔을 입사하여 KSTAR 토카막 실험의 H-mode 달성과 운전 시나리오 연구에 많은 기여를 하고 있다. 한국원자력연구원에서 최초로 개발된 이온원은 미국 TFTR 장치에서 사용되었던 US LPIS (Long Pulse Ion Source)를 기본으로 하여 국내 개발을 수행하였다. 이 온원은 크게 플라즈마를 발생시키는 플라즈마 발생부와 발생된 이온을 인출 및 가속시키는 가속부로 구성되는데, 개발과정에서 가장 먼저 KSTAR의 장주기 운전에 적합하도록 플라즈마 방전부와 가속부의 냉각회로를 요구되는 열부하에 맞게 설계 수정하였다. 그 후 플라즈마 방전부는 방전 시간과 안정성, 플라즈마 밀도의 균일도, 정격 운전, 방전 효율 등을 고려하여 수정 보완하며 개발을 진행하여왔다. 가속부의 경우 국내 제작기술의 한계를 극복하기 위해 빔 인출그리드를 TFTR의 US LPIS 모델의 슬릿형 그리드 타입에서 원형 인출구 타입으로 변경하였으며, 이후 가속 전극의 고전압 내전력 문제, 빔 인출 전류와 전력, 인출 빔의 광학적 질(quality), 빔 인출 시간 동안의 안정성 등을 위해 그리드의 크기와 간격, 모양 등을 변경하여 개발을 수 행하여 왔다. 이 논문은 한국원자력연구원에서 개발이 진행되어 왔던 이온원들을 시간적으로 되짚어 보면서 현재까지의 성과와 문제점, 그리고 앞으로의 개발 방향에 대해 논의하고자 한다.

• Journal of Microbiology and Biotechnology
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• v.24 no.7
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• pp.943-953
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• 2014

The XylH gene (1,167-bp) encoding a novel hemicellulase (41,584 Da) was identified from the genome of Microbacterium trichothecenolyticum HY-17, a gastrointestinal bacterium of Gryllotalpa orientalis. The enzyme consisted of a single catalytic domain, which is 74% identical to that of an endo-${\beta}$-1,4-xylanase (GH10) from Isoptericola variabilis 225. Unlike other endo-${\beta}$-1,4-xylanases from invertebrate-symbiotic bacteria, rXylH was an alkali-tolerant multifunctional enzyme possessing endo-${\beta}$-1,4-xylanase activity together with ${\beta}$-1,3/${\beta}$-1,4-glucanase activity, which exhibited its highest xylanolytic activity at pH 9.0 and 60oC, and was relatively stable within a broad pH range of 5.0-10.0. The susceptibilities of different xylosebased polysaccharides to the XylH were assessed to be as follows: oat spelts xylan > beechwood xylan > birchwood xylan > wheat arabinoxylan. rXylH was also able to readily cleave p-nitrophenyl (pNP) cellobioside and pNP-xylopyranoside, but did not hydrolyze other pNP-sugar derivatives, xylobiose, or hexose-based materials. Enzymatic hydrolysis of birchwood xylan resulted in the product composition of xylobiose (71.2%) and xylotriose (28.8%) as end products.

• Journal of the Korean Geophysical Society
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• v.3 no.2
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• pp.127-138
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• 2000

This study was conducted to examine the differences between dynamic and static elastic constants by use of some laboratory tests of cement mortar specimens which have different water/cement mixing ratios. Specific gravity measurement, ultrasonic velocity estimating and uniaxial compression test were adopted to acquire the dynamic and static elastic constants. Digital data acquisition and processing enhanced the accuracy of estimating the velocities of specimens drastically, Also, the method using the gradient of propagation delay time in according to increment of specimen length more enhanced the accuracy than the method using the only one specimen length over total propagation time. The correlation between density and the P and S wave velocity of specimens shows reliable positive relation and the correlation between density and the strength of uniaxial compression has the similar relationship. The dynamic Young's modulus $(E_D)$ is alway greater than the static Young's modulus $(E_S)$ and there is increasing tendency of the ratio $(E_D/E_S)$ according to the increase of density or strength of the specimens. On the other hand, there is no typical relationship between dynamic Poisson's ratio $({\nu}_D)$ and static Poisson's ratio $({\nu}_S)$ and just the ratio of ${\nu}_D/{\nu}_S$ ranges front 69 to 122 %.

• Journal of Korean Society of Forest Science
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• v.89 no.2
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• pp.145-160
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• 2000

This study is focused to the national park of Korean typical Sea Hally$\check{o}$ Haesang, and its visual resources and practiced inspect course by the way of suppositions and tests, to show the visual resource management objectively, and that of qualitative basic data. Accordingly by measuring the physical amount spatial structure with the visual amount originated from the Mesh Analyzing Method and the Visual Preference from the Scenic Beauty Estimation(S.B.E.) method and analyzed the valuation of the visual resource by Iverson method. Spatial image structure measured by Semantic Differential(S.D.) Scale was shown through the factor analysis algorithm for the analyzing psychological amount and examined the flowing out of decisive factor and the objective importance related to the mutual factors by appling the measurement of the visual quality. As a national Park, the visual factors that have natural landscape harmonized with forest, sky, surface of the water, curious stones and rocks, and temples should be escalated their values affirmatively so as to be the scenery of pointed direction and enjoyable, and it is of more needed for visual resource and its' controlling technique to make artificial structures more intentional planning and systemical setting. When we are viewing the improvement for the national park along with the visual resource management, reasonable level of development is needed, because when men interference surpass plantations and leasts will be damaged and the quality of natural landscape can be lowered, so it is needed to set up a management end, tangibly or clearly; and it is permitted limit coming and going ablably by accounting the suitable number for availing. But the controling end should be set in every level, positive management, very actively within the permissive varcability. It is the main business for the national park to prevent the damage from human for their gay life or to prevent the damage of a land carpet, and to restorate for the visual resource management.

• Korean Journal of Materials Research
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• v.21 no.7
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• pp.357-363
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• 2011

In this paper, high temperature oxidation behavior of newly developed alloys, Ti-6Al-4Fe and Ti-6Al-1Fe, is examined. To understand the effect of Fe on the air oxidation behavior of the Ti-Al-Fe alloy system, thermal oxidation tests are carried out at $700^{\circ}C$ and $800^{\circ}C$ for 96 hours. Ti-6Al-4V alloy is also prepared and tested under the same conditions for comparison with the developed alloys. The oxidation resistance of the Ti-Al-Fe alloy system is superior to that of Ti-6Al-4V alloy. Ti-6Al-4V shows the worst oxidation resistance for all test conditions. This is not a result of the addition of Fe, but rather it is due to the elimination of V, which has deleterious effects on high temperature oxidation. The oxidation of the Ti-Al-Fe alloy system follows the parabolic rate law. At $700^{\circ}C$, Fe addition does not have a noticeable influence on the amount of weight gain of all specimens. However, at $800^{\circ}C$, Ti-6Al-4Fe alloy shows remarkable degradation compared to Ti-6Al-1Fe and Ti-6Al. It is discovered that the formation of $Al_2O_3$, a diffusion resistance layer, is remarkably hindered by a relative decrease of the ${\alpha}$ volume fraction. This is because Fe addition increases the volume fraction of ${\beta}$ phase within the Ti-6Al-xFe alloy system. Activities of Al, Ti, and Fe with respect to the formation of oxide layers are calculated and analyzed to explore the oxidation mechanism.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2006.06a
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• pp.130-137
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• 2006

본 논문은 디지털홈서비스의 실제 이용자들에 대한 실증분석을 통해 수용에 영향을 미치는 요인들을 밝히기 위한 연구이다. 디지털홈서비스의 특성에 맞게 기술수용모형(TAM)을 확장, 수정된 연구모형을 개발, 가설을 설정하여 분석하였다. 외부변수로 이용자의 특성을 채택하였으며, 디지털홈서비스가 가정 내 기술임을 고려하여 신념변수로 '지각된 이용용이성'과 '시각된 즐거움'외에 '지각된 편의성', '지각된 안전성', '지각된 삶의 질 향상'이라는 변수를 추가하였고 종속변수로는 '이용행동'을 설정하였다. 205명의 실제 이용자를 대상으로 한 설물조사 중 201개의 유효표본을 분석하였고, 신뢰성과 타당성 모두 통계적으로 적합한 것으로 나타났다. AMOS 4를 이용한 구조방정식 모형분석을 통해 24개의 가설검증 결과, 13개의 가설이 채택되었다. 이용자 개인의 특성 중 경험과 교육훈련은 지각된 이용용이성에 정(+)의 영향을 미쳤으며 혁신성은 지각된 즐거움, 지각된 편의성, 지각된 안전성, 지각된 삼의 질 향상에 대하여 정(+)의 영향을 미치고 있었다. 또한 지각된 이용용이성이 다른 신념변수인 지각된 즐거움, 지각된 편의성, 지각된 안전성, 지각된 삶의 질 향상에 정의 영향을 미치고 있었다. 종속변수인 이용행동에는 지각된 즐거움과 지각된 편의성, 지각된 삶의 질 향상이 긍정적인 영향을 미치나, 지각된 이용용이성과 지각된 안전성은 영향을 미치지 않았다. 가정에서 쉽게 이용할 수 있다는 것만으로는 적극적인 이용 행동을 기대할 수 없으며, 즐거움 및 실용적인 효익들의 제공 및 이를 위한 다양한 컨텐츠와 프로그램 개발등이 매우 중요하다는 것을 시사하고 있다.3-25%까지 감소하였다. 하지만 산간지역에서는 발육속도가 빨라지고 수량이 증가하거나 큰 변화가 없는 곳도 많아 온난화조건에서도 지역별 정밀기후 추정과 이에 근거한 최적품종의 선택, 이앙기 및 수확기 등 생육기간의 조절이 온난화 대응기술로서 유효할 것으로 기대된다.결과를 분석한 데이터를 차기 메일 발송에 꾸준히 적용함으로써 성공적인 이메일 마케팅 결과를 얻을 수 있을 것으로 기대된다.여 수평적인 의견도출과 각자 역할의 확대 및 변화를 시도할 수 있는 제작흐름이 되도록 고안된 제작구조이다.성을 환기시켜 객관적이고 비판적인 의식을 환기시키는 브레히트의 '소격화'의 효과가 소비자의 관심을 환기시켜 특정한 목적을 달성하려는 광고에 효율적으로 적용된 예 인 것이다. 재미, 기타 독특한 체험을 통해 소비자에게 유희라는 쾌락적 경험을 제공하고자 한다.고도로 통계적 유의차(p<0.001)가 있었다. 즐기는 음료로는 ${\ulcorner}$콜라${\lrcorner}$가 가장 많았으며(46.8%), 그 다음은 사이다, 주스 등의 순으로 나타났으나, 남 여 대학생간에는 유의성있는 차이는 없었다. 음식의 먹는 시기는 점심과 저녁사이의 ${\ulcorner}$간식${\lrcorner}$이 가장 많았으며(42.2%), 남 여 대학생간에는 유의한 차이는 없었다. 패스트푸드는 많은 사람들이 ${\ulcorner}$맛${\lrcorner}$이 좋기 때문에 이용하며(62.8%), 남 여 대학생간에는 통계적 유의성(p<0.05)이 인정되었다. 5. ${\u