• 대한환경공학회지
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• 제31권2호
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• pp.147-152
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• 2009

본 연구에서는 톨루엔 계열 화합물로 오염된 환경에 대해 고정화한 유전자 재조합 균주 KG1206의 적용 가능성에 대해 조사하였다. 재조합 균주 KG1206은 직접 유도제인 m-toluate, benzoate 뿐만 아니라 톨루엔, 자일렌 이성질체가 간접 유도제로서 발광 활성을 나타낸다. 연구에 의해 결정된 고정화 프로토콜의 최적 조건은 다음과 같다: 균주 농도(1 : 1 (v/v)), 오염원 용액(인산염 완충액), 발광 측정에 필요한 비드 수(4개), 5가지 오염원에 대한 최대 발광 활성은 일반적으로 m-toluate > p-xylene > 톨루엔 > o-xylene > m-xylene 순으로 나타났다. 생물발광과 오염원 감소는 HPLC로 확인하였으며, 고정 균주에 의해 초기 5 mM m-toluate는 5시간 배양 후 약 48%의 감소율을 나타내었으며 계속 분해되는 경향이 관찰되었다. 알긴산 균주 고정화에 대한 본 연구 결과는 톨루엔 계열 화합물을 함유한 석유계 탄화수소에 오염된 특정 환경을 생물학적 모니터링에 유용한 방법으로 사용할 수 있을 것이다.

• 한국해양환경ㆍ에너지학회지
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• 제5권4호
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• pp.63-73
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• 2002

본 논문은 1988년 2원에 포항 앞바다에서 침몰한 총톤수 995톤의 유조선 경신호에 대한 수중 조사 작업과 그 결과를 다루고 있다. 조사는 경신호에 의한 추가 해양오염가능성을 파악하기 위하여 2001년 9원에 약 10일간의 일정으로 수행되었으며 첨단 해양조사장비인 ROV와 유인잠수정, 초음파 투께 계측장치 등을 이용하여 선체상태와 기름의 유출상황, 선체외판의 부식상태 통을 조사하였다. 조사 결과, 선체에서 계속적으로 소량의 기름이 유출되고 있는 것으로 확인되었으며 선체의 부식 상태 조사를 위해 선체의 일부에서 선체 두께 측정이 이루어졌다. 조사 결과와 기존 사고 보고서의 내용을 바탕으로 잔존유의 양을 추정하였을 때, 조사당시 선체에는 약 600㎘의 기금이 잔존하고 있는 것으로 추정되었으며 향후 선체외판의 부식으로 인해 잔존유가 추가 유출될 가능성이 있는 것으로 판단되었다 이와 함께 유출유 확산 예측시뮬레이션을 통해 특정한 기상상태에서는 유출된 기름이 주변해역을 오염시킬 수 있는 가능성을 확인하였다.

• 한국식품영양과학회지
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• 제18권1호
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• pp.47-52
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• 1989

곰팡중에서 melanoidin의 탈색력이 있는 Aspergillus awamori, B-2을 선별하여 탈색력을 실험하였다. Aspergillus awamori, B-2는 3.0% glucose, 0.5% yeast extract, 0.1% $KH_2PO_4$, 및 0.05% $MgSO_4{\cdot}7H_2O$을 함유하는 melanoidin 용액(pH 7.0) 에서 5일 동안 $37^{\circ}C$에서 배양했을때 가장 높은 탈색력을 나타내었다. 탈색력을 효과적으로 하기 위하여 Ca-alginate로 고정화하여 최적조건에서 계속적으로 탈색하였을때 mycelia 단독보다는 더욱 효과적이었다. Melanoidin 탈색력은 최적 조건에서 10일 동안 반응하였을때 약 70%을 나타내었다. 고정 화한 mycelia의 재사용에 의한 계속적인 탈색을 시도하였던바 15일 동안 연속적으로 반응시켜도 약 60-70%의 탈색력을 계속 유지하였다.

• 한국지진공학회논문집
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• 제20권7_spc호
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• pp.435-441
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• 2016

The Korean peninsula has known as a minor-to-moderate seismic region. However, some recent studies had shown that the maximum possible earthquake magnitude in the region is approximately 6.3-6.5. Therefore, a seismic vulnerability assessment of the existing infrastructures considering ground motions in Korea is necessary. In this study, we developed seismic fragility curves for a continuous steel box girder bridge and two typical transmission towers, in which a set of seven artificial and natural ground motions recorded in South Korea is used. A finite element simulation framework, OpenSees, is utilized to perform nonlinear time history analyses of the bridge and a commercial software, SAP2000, is used to perform time history analyses of the transmission towers. The fragility curves based on Korean ground motions were then compared with the fragility curves generated using worldwide ground motions to evaluate the effect of the two ground motion groups on the seismic fragility curves of the structures. The results show that both non-isolated and base-isolated bridges are less vulnerable to the Korean ground motions than to worldwide earthquakes. Similarly to the bridge case, the transmission towers are safer during Korean motions than that under worldwide earthquakes in terms of fragility functions.

• 한국건강관리협회지
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• 제2권2호
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• pp.187-197
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• 2004

Owing to continuous economic growth, an increased standard of living, and improvements to health care in Korea, the life expectancy of Koreans rose from 69.0 years in 1985 to 71.3years in 1990. It continued to rise throughout the 1990s, and, by 2002, had reached 76.5years for the general population and 80.0 years for Korean females. Similarly, the percentage of the Korean population that is 65 years of age or older increased from 3.1 in 1970 to 7.1in 2000, and is expected to reach approximately 14,0 in 2019. Thus, according to this estimate, Korea will have evolved from an "aging society" to an "aged society" in only 19years. In the case of other countries, this same transformation has generally taken 2 to 5times longer. One of the major issues related to Korea's rapidly aging population relates to the health problems of the elderly. According to the 2002 National Health Survey Report, 87,6 percent of the elderly were reported to Have at least one chronic disease. In other words, almost 9out of every 10 elderly persons in Korea were suffering from a chronic illness, This, clearly, places a significant economic burden on Korean society in the form of increased health care Costs. This paper examines the increasing prevalence of chronic diseases within Korea's rapidlv aging population and offers some possible short- and long-term solutions to cope with the increased burden being placed on Korea's health care system. These include the basic services at local health centers for the elderly and the national life-long health promotion programs that aim to correct unhealthy behavior, such as smoking, the excessive use of alcohol, and poor eating and exercise habits.

• 조명전기설비학회논문지
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• 제29권12호
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• pp.61-67
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• 2015

Certainly, we are living in a true mobile society. At the end of 2014, approximately 40million 560thousand people are subscribed to smartphone services in Korea, using more than 2000MB of mobile data per a person. The use of smartphone is expected to increase. Moreover, smartphone moves toward becoming a requisite for modern people. Under the circumstances, high-speed communication services such as LTE provide high quality services anywhere and anytime and, furthermore, the development of high performances of the application makes the life patterns of modern people link directly to smartphone. Almost every day, new creative services are being introduced and the demands of on-line streaming services such as high-performance game and YouTube are increasing day after day. However, although smartphones are getting smarter and high quality services are rapidly growing, consumers still complain about the insufficient usage time caused by the capacity of batteries. In order to solve this problem, this thesis suggests EDLC(Electric Double-Layer Capacitor) uses as a supplemental power supply to keep the continuity of work while switching batteries. Through this approach, the running time of smartphone becomes longer as the number of batteries without power off and the purpose of this study is to maximize the convenience of using smartphone by eliminating the initialization of memories and the loss of time of rebooting while batteries are switched.

• 대한영양사협회학술지
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• 제22권3호
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• pp.163-178
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• 2016

This study was designed to examine the level of milk consumption and perception of the school milk programs among elementary, middle and high school students, which provides the information to improve the school milk program. Using a self-administered questionnaire survey, the data collected from 1,725 students nationwide were analyzed. The results showed that whole milk was the type of milk most frequently drunk by the students, although flavored milk and yogurt products were also highly preferred. When asked whether they wanted the school milk program or not, approximately 30% of the students in the schools presently participating in the school milk program and 50% of the students in the schools not participating the school milk program answered "yes". However, all of the respondents preferred to have a choice for the school milk program. The elementary school students showed a higher level of satisfaction with the school milk program than the middle and high school students. Especially, the level of satisfaction with the taste and flavor of the milk was the lowest among the various satisfaction items. However, the students were reported to believe that milk is highly nutritious and good for their health in the present study. Our results suggest that providing a choice of dairy products would improve the students' satisfaction with the school milk program, and that continuous education about the benefits of drinking milk would also encourage them to participate in the school milk program.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.72-76
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• 2010

초저온 추진제를 사용하는 액체로켓용 인젝터의 개발을 위해서는 수류시험과 더불어, 연소시험을 통한 성능검증, 점화 cyclogram의 최적화 및 내부연소 유동장에 대한 열-유체역학적 특성에 대한 연구가 필요하다. 본 연구에서는 대학실험실 급에서 운용할 수 있는 범위의 가압식 초저온 추진제 공급 및 제어장치를 이용하여, LOX-$GCH_4$를 추진제로 하는 동축형 스월 인젝터의 연소시험을 수행하였다. 점화 cyclogram 최적화를 통해 O/F ratio 약 2.80, 총질량유량 약 0.19 kg/s의 LOX-$GCH_4$ 추진제를 점화 및 연소시켰고, 연소실 압력은 1.43 MPa, 추력은 38.7kgf으로 측정되었다.

• 한국재료학회지
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• 제18권3호
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• pp.148-152
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• 2008

A new cost-effective atomic layer deposition (ALD) technique, known as Proximity-Scan ALD (PS-ALD) was developed and its benefits were demonstrated by depositing $Al_2O_3$ and $HfO_2$ thin films using TMA and TEMAHf, respectively, as precursors. The system is consisted of two separate injectors for precursors and reactants that are placed near a heated substrate at a proximity of less than 1 cm. The bell-shaped injector chamber separated but close to the substrate forms a local chamber, maintaining higher pressure compared to the rest of chamber. Therefore, a system configuration with a rotating substrate gives the typical sequential deposition process of ALD under a continuous source flow without the need for gas switching. As the pressure required for the deposition is achieved in a small local volume, the need for an expensive metal organic (MO) source is reduced by a factor of approximately 100 concerning the volume ratio of local to total chambers. Under an optimized deposition condition, the deposition rates of $Al_2O_3$ and $HfO_2$ were $1.3\;{\AA}/cycle$ and $0.75\;{\AA}/cycle$, respectively, with dielectric constants of 9.4 and 23. A relatively short cycle time ($5{\sim}10\;sec$) due to the lack of the time-consuming "purging and pumping" process and the capability of multi-wafer processing of the proposed technology offer a very high through-put in addition to a lower cost.

• 융합신호처리학회논문지
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• 제3권4호
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• pp.35-41
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• 2002

복잡한 문제들의 근사해를 구하기 위하여 최근 다양한 방법들이 소개되고 있다. 이러한 방법들은 주로 금속의 서랭(Annealing)에 의해 금속분자의 에너지가 최저점에 도달하는 과정을 모의실험한 최적화 기법(Simulated Annealing), 생물의 적자생존(Survival of Fittest)과정을 이용한 최적화 기법인 유전적 알고리즘(Genetic Algorithm)등 물리적 현상이나 생물 ?생명에 관련된 모의를 최적화 문제에 응용한 방법들이다. 최근에 소개된 Particle Swarm Optimization(PSO)는 주로 조류나 어류등의 생물의 무리가 각각의 개체가 가지고 있는 정보를 공유해가며 먹이를 찾아가는 과정을 모의한 기법이다. 하지만, 이 기법의 탐색과정이 명확하게 밝혀져 있지 않다. 본 논문에서는 PSO의 탐색과정을 가시화 하는 것을 목적으로 한다. 탐색과정을 가시화 하는 작업을 통해 그 탐색 능력을 시각적으로 파악하는 것이 가능하며 기법에 관한 이해를 돕고 교육적 효과도 기대 가능하다.