• 지역사회간호학회지
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• 제15권1호
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• pp.84-94
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• 2004

Purpose: The purpose of this study was to examine the health care management status of preschoolers depending on the children's characteristics. Methods: The sample of this study were 212 mothers of preschoolers attending Child Care Centers in three cities, Seoul, Daejon, and Suwon, in Korea. A self administered questionnaire developed by investigators was used to collect data from September 15 to October 31, 2002. Data was analyzed with SPSS 11.5 Win program. Results: 5.7% of the children had not completed their vaccination programs. Children who were second or later birth order showed less complete vaccination rates than firstborn babies. Children who had working mothers showed less complete vaccination rates than those whose mothers did not work. Among the various vaccinations, the DPT and MMR booster vaccination rates were the lowest. Home safety scores were higher when mothers have younger children. higher monthly incomes and reside in apartment type houses. Forty one(41%) of the preschoolers experienced accidents, and the accident rate was higher in boys and children with easy temperament. The most frequently experienced accident was laceration. Twenty eight point eight percent(28.8%) of the children experienced hospitalization because of various diseases. Most of the mothers perceived their children healthy. However, children who were second or third born were perceived less as healthy. Children in families with less monthly income were perceived as less healthy. Conclusions: This study provided basic data about preschoolers' health care management status focusing on vaccinations and accident rates. More attention should be paid to preschoolers' health and safety. Related factors found in this study should be considered when providing anticipatory guidance for parents.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 춘계 학술대회논문집
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• pp.83-86
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• 2007

Turbulent flow analysis is conducted around the multi-stage launch vehicle including base region and detachment motion of strap-on boosters due to resultant aerodynamic forces and gravity is simulated. Aerodynamic solution procedure is coupled with rigid body dynamics for the prediction of separation behavior. An overset mesh technique is adopted to achieve maximum efficiency in simulating relative motion of bodies and various turbulence models are implemented on the flow solver to predict the aerodynamic forces accurately. At first, some preliminary studies are conducted to show the importance of base flow for the exact prediction of detachment motion and to find the most suitable turbulence model for the simulation of launch vehicle configurations. And then, developed solver is applied to the simulation of KSR-III, a three-stage sounding rocket researched in Korea. From the analyses, after-body flow field strongly affects the separation motions of strap-on boosters. Negative pitching moment at initial stage is gradually recovered and a strap-on finally results in a safe separation, while fore-body analysis shows collision phenomena between core rocket and booster. And a slight variation of motion is observed from the comparison between inviscid and turbulent analyses. Change of separation trajectory based on viscous effects is just a few percent and therefore, inviscid analysis is sufficient for the simulation of separation motion if the study is focused only on the movement of strap-ons.

• 대한기계학회논문집B
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• 제40권4호
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• pp.255-262
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• 2016

철도차량의 안정성과 신뢰성을 위해 상시 자가진단 시스템의 필요성이 높아지고 있다. 통상적으로 이러한 모니터링 시스템에는 유선 센서가 쓰여 왔는데, 설치 장소의 제약이 적은 무선 센서의 활용과 유지보수의 문제를 위해서는 무선 센서의 전원 문제를 해결하여야 한다. 따라서 본 연구에서는 고속으로 주행하는 차량 주변의 에너지를 활용하여 친환경적이면서 반영구적인 자가 발전의 방편으로 열전 발전의 적용성을 검토하였다. 차량의 주행 조건에 따라 열전 발전 모듈이 설치될 차축 베어링 커버의 온도 차이에 대한 측정이 먼저 이루어졌고, 여기에 상용 열전 소자 모듈을 장착하여 그 성능을 테스트 하였다. 주어진 조건에서 출력을 높이기 위해 부하 저항 및 열전 소자 전용 회로를 적용하여 효과를 분석한 결과, 저온부의 효과적인 냉각 및 열손실의 최소화를 통해 열전 발전을 통한 무선 센서 전원 공급이 가능할 것으로 판단된다.

• 대한기계학회논문집B
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• 제34권8호
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• pp.775-782
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• 2010

본 연구는 대형 석탄 화력 발전소 탈황설비 내 흡수탑의 성능향상을 위하여 Tray 설치 가능성을 검토하기 위한 연구로 전산 유체역학(CFD) 기법을 이용하여 탈황설비 내 흡수탑의 내부유동을 전산해석 하였다. 흡수탑 내의 Gas와 Slurry의 거동에 대한 사실적 묘사를 위해 Euler-Lagrangian 기법을 이용한 전산해석을 수행하였다. 기존 흡수탑 내에 Tray를 설치함에 따라 탈황설비 내에서 Slurry의 체공시간 증가로 인한 펌프동력 절감과 압력강하 증가로 인한 Fan의 소요동력 증가에 대하여 중점적으로 비교 및 고찰하였다. 그 결과 Tray를 설치함에 따라 흡수탑 내에 Slurry의 체공시간과 배기가스의 압력강하가 증가되는 것을 확인할 수 있었다. 체공시간 증가로 인하여 절약된 동력이 압력강하에 의한 동력 소모량 증가보다 더 큰 것으로 확인되었다.

• 한국수자원학회논문집
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• 제44권12호
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• pp.1001-1013
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• 2011

이웃한 상수도시스템의 공급 가능지역이 중첩될 경우, 이들 시스템을 연계함으로써 경제성과 수질 조건을 만족시키는 조건별 용수공급체계를 구축하는 것이 필요하다. 용수수요 조건별 경제적 급수구역과 최적 펌프운영율을 산정하기 위하여 관망수리해석 모형(EPAnet)과 네트워크 최적화모형(KModSim)을 연계 하는 최적 네트워크모형을 개발하였다. 개발된 최적 네트워크 모형을 사등가압장, 구천댐 그리고 연초댐의 3개 상수원이 존재하는 거제지역 상수도시스템에 적용하고 2007년 운영 결과와 비교하는 방법으로 모형을 검정하였다. 최적 네트워크 모형의 적용성을 검토하기 위하여, 2011년 용수자료를 이용하여경제적급수구역변경에따른펌프운영및 수질의 적정성을평가 하였다. 평가결과본 모형은 수량, 경제성 그리고 수질을 모두 만족하는 최적해를 구하는 것으로 나타나 송배수계통간의 최적 설계 혹은 최적연계운영율을 구하기 위한 모형으로 활용이 가능하다.

• 한국정보통신학회논문지
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• 제17권7호
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• pp.1660-1671
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• 2013

본 논문에서는 빛 에너지 하베스팅 자가발전 시스템을 위한 두 가지 구조의 전력관리 회로를 제안한다. 첫 번째는, 솔라셀이 부하가 동작할 수 있는 충분한 전압을 출력하는 경우, 전력관리회로를 통해 직접 솔라셀의 에너지를 부하로 공급하는 구조이다. 두 번째는 초소형 솔라셀이나 집적화된 솔라셀에서처럼 출력전압이 0.5V 이하로 매우 작아서 부하를 직접 구동할 수 없는 경우, 전압부스터를 사용하여 충분한 전압까지 승압한 후, 이를 전력관리회로를 통해 부하로 공급하는 구조이다. 이 두 가지 구조의 전력관리 회로는 $0.18{\mu}m$ CMOS 공정으로 설계 및 제작되었으며, 측정을 통해 성능을 비교 분석하였다.

• 한국가금학회지
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• 제28권1호
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• pp.55-59
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• 2001

The objective of these experiments gas to investigate the feeding of Powerfeel supplementation on performance and intestinal microflora of broiler chicks. Five treatments were allocated into 0, 0.025, 0.050, 0.075, 0.10% Powerfeel with four replications for five weeks. Diets contained 21.5% CP, 3,100 kcal/kg ME for the first three weeks and 19% CP, 3,100 kcal/kg ME for the rest two weeks. Weight gain, feed intake, feed conversion were weekly measured. E. coli and Salmonella were examined from cecum and ileum at the end of experiment. ND titer were also measured at five weeks old after first and booster vaccination at 14 and 21 days of age. In experiment 1, Weight gain of Powerfeef treatments was significantly higher for five weeks (P〈0.05). Feed intake increased on all Powerfeel treatments. Chicks fed Powerfeel improved feed conversion ratio(FCR) significantly compared to that of control (P〈0.05), but was not shown the consistency. In experiment 2, Weight gain and feed consumption of chicks fed Powerfeel were tended to increase, but were not statistically different from control. Powerfeel treatments showed significantly lower FCR than control(P〈0.05). The number of Salmonella and E. coli of chicks ileum fed Powerfeel were highly decreased, compared to those of control in both experiments. Powerfeel supplementation seemed to decrease the number of both Salmonella and E. coli in illeum, but was not consistency in cecum. Chicks fed Powerfeel showed significantly higher ND titer than control (P〈0.05). These results indicated that the optimum level of Powerfeel to maximize the performance of broiler chicks were estimated from 0.050 to 0.075% in broiler diets.

• Parasites, Hosts and Diseases
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• 제36권2호
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• pp.121-126
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• 1998

닭와포자충 감염이 다른 병원체에 대한 닭의 체액성 면역에 미치는 영향을 규명하기 위한 연구의 일환으로 2일령 SPF 병아리에 $5{\;}{\times}10^5$의 닭와포자충 오오시스트를 한 번에 경구투여한 다음 4일과 21일 두 번에 걸척 뉴캣슬병 불활화 (사독) 백신을 접종하였다. 오오시스트 접종 후 2주부터 1주 간격으로 13주까지 채혈하여 혈구응집억제반응으로 ND HI $log_2$ 역가를 경시적으로 측정하여 대조군과 비교, 검토하였다. 일반적으로 뉴캣슬병 바이러스에 대한 Hl가는 전 실험기간을 통하여 대조군에 비하여 실험군이 상당히 낮았으며 (p<0.01), 보다 빨리 음전하는 경향이었다. 백신의 보강주사 후 역가는 점점 높아져서 2주 ($5.00(\;}{\pm}{\;}0$; 비감염 대조군)와 4주 ($3.88{\;}{\pm}{\;}0.6658$; 감염 실험군)에 최고치에 이른 다음 점점 낮아졌다. 한편, 분변 내의 오오시스트 배설 양상은 통상적인 감염례와 같았다. 이로 미루어 보아 병아리가 닭와포자충에 감염되면 건강한 병아리에 비하여 뉴캣슬병 바이러스에 대한 면역억제 현상이 일어나 감수성이 증가할 수 있을 것으로 생각된다.

• Biomolecules & Therapeutics
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• 제21권4호
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• pp.290-298
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• 2013

This study examined the effects of calcium (Ca) gluconate on collagen-induced DBA mouse rheumatoid arthritis (CIA). A single daily dose of 200, 100 or 50 mg/kg Ca gluconate was administered orally to male DBA/1J mice for 40 days after initial collagen immunization. To ascertain the effects administering the collagen booster, CIA-related features (including body weight, poly-arthritis, knee and paw thickness, and paw weight increase) were measured from histopathological changes in the spleen, left popliteal lymph node, third digit and the knee joint regions. CIA-related bone and cartilage damage improved significantly in the Ca gluconate-administered CIA mice. Additionally, myeloperoxidase (MPO) levels in the paw were reduced in Ca gluconate-treated CIA mice compared to CIA control groups. The level of malondialdehyde (MDA), an indicator of oxidative stress, decreased in a dose-dependent manner in the Ca gluconate group. Finally, the production of IL-6 and TNF-${\alpha}$, involved in rheumatoid arthritis pathogenesis, were suppressed by treatment with Ca gluconate. Taken together, these results suggest that Ca gluconate is a promising candidate anti-rheumatoid arthritis agent, exerting anti-inflammatory, anti-oxidative and immunomodulatory effects in CIA mice.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.71-74
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• 2005

In manufacturing automotive parts, such as engine cradles, frame rails, subframes, cross-members, and other parts from circular tubes, pre-bending and pre-forming operations are often required prior to the subsequent tubular hydroforming process. During some pre-forming operations, the cross section of a bent circular tube is crushed into an oval-like shape to ensure proper geometry and sufficient clearance in the hydroforming dies. For such applications, the use of oval Instead of circular tubes could be an effective means of eliminating the pre-forming step. The oval tube could also be produced with less thinning and with less strain on the outside of the bend when controlled by a booster system without the use of mandrel. Hence, the understanding of the issues that occur in the bending of oval tubes is worthy of Investigation. This paper presents parametric studies on the bending of oval tubes without a mandrel. The finite element modeling technique is used to examine the deformation characteristics for both circular and oval tubes. In the simulations, the bending process parameters of bend radius, aspect ratio of the tube ovalness, and tube wall thickness are varied. Observations are made to obtain a hoop-buckle limit diagram in terms of a non-dimensional shape degradation factor. Suggestions based upon developed criteria are made on the acceptability of bend tubes suitable for hydroforming applications without the need ofa pre-forming step or the used of a mandrel.