• 해양환경안전학회지
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• 제20권3호
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• pp.259-269
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• 2014

The objectives of this study to determine seasonal changes in species composition and abundance of fish and decapod assemblage, and the relationships between environmental factors and their abundance in an eelgrass bed of Jindong Bay. A total of 26 fish species and 29 decapod species were collected by a small beam trawl from an eelgrass bed in Jindong Bay in 2002. The dominant fish species were Hexagrammos otakii, Pholis neulosa and P. fangi and these accounted for 48.4 % in the total number of individuals. Dominant decapod taxa were Palaemon macrodactylus, Charybdis japonica, Pagurus minutus and C. bimaculata. These were primarily small species or early juveniles of larger species. Species composition and abundance varied greatly showing a peak in the number of individuals in April and May, and peak biomass in fish in July and decapods in August. Catch rate was low in winter months both in fish and in decapod. Seasonal changes in the abundance of fishes and decapods corresponded with eelgrass biomass and abundance of food organisms indirectly.

• 청정기술
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• 제12권4호
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• pp.224-231
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• 2006

현탁액중의 부유입자를 제거하는 입상여과공정을 Network 모델을 이용하여 여과효율과 압력손실에 대해 예측하였다. 구형 여재로 구성되어 있는 여재 층을 node와 원통형 bond로 구성된 network로 가정하였으며 여과 공정을 통해 부유입자는 bond 표면에 포집된다. 원통형 bond에서의 여과효율은 bond의 세공부피를 단위 cell의 유체 막 부피로 가정하여 입자의 경로 분석을 이용하여 구하였으며, 포집된 부유입자가 추가적인 여재로서의 역할은 bond 세공이 좁아짐에 따른 효율 증가로 나타내었다. 또한 세공이 좁아짐에 따른 압력손실도 예측하였다. 본 network 모델의 세공 분포를 부여하는 과정의 stochastic한 성질로 인하여 많은 전산모사가 필요하지만, 본 모델을 이용하여 여과효율과 압력손실을 동시에 예측할 수 있었다.

• 물과 미래
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• 제28권4호
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• pp.147-154
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• 1995

본 연구에서는 특별한 에너지 감세를 위한 수공구조물이 설치되지 않은 중 소규모 단락부 하류부에서 자유낙하하는 수맥으로 인하여 발생되는 비점착성 하상재료의 세굴특성을 수리모형실험을 통하여 분석하였다. 단락수맥 하류부에서의 세굴특성을 분석하기 위하여 먼저 직사각형 단락수맥의 흐름특성을 조사하였으며, 하상재료, 유량, 하류수심을 변화시키면서 세굴공의 직하류부에 생성되는 둔덕(mound)의 유무로 인한 세굴특성을 비교 분석하였다. 평형세굴심 뿐만 아니라 둔덕의 높이도 밀도 후르드수의 함수로 표시되며, 밀도 후르드수는 다른 무차원량 보다 평형세굴심과 비교적 깊은 관계가 있는 것을 확인하였다. 단락부 하류부 하상 보호공의 설계시 둔덕의 영향을 고려해야 한다는 결론을 얻었다.

• 수산해양교육연구
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• 제18권3호
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• pp.236-243
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• 2006

A series of surveys are performed to evaluate the abundance, composition and distribution of marine debris on the sea bed around the Busan port. In order to set up a master plan for the marine environmental pollution the relevant maritime authority must understand how many and w㏊t kinds of marine litters are distributed on the sea bed. At first we planed to survey areas divided regularly according to the coast line but there were many sea going vessels and fishing boats. So we selected and surveyed the around area where there were no sea going vessels or fishing boats.The obtained results are as follows: 1. The mean values of litters in number and weight are 5.8 pieces/㏊. and 3.5㎏/㏊. respectively. 2. The highest density in terms of number are vinyl and plastic item, and in weight are fishing gear and ship articles. 3. The nearer to the shore we surveyed the more we collected in terms of the density of marine litters in number and in weight per hectare. 4. Eel pot, oiled waste, rope, others, other pot and net of fishing gear litters in number were 59.9, 22.7, 7.9, 4.5, 3.1 and 1.9% respectively. 5. There is no relationship between the amount of fish caught and the amount of marine debris.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.244-249
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• 2005

Flow distribution and pressure drop analysis for an inlet plenum of a Pebble Bed Modular Reactor (PBMR) have been performed using Computational Fluid Dynamics. Three-dimensional Navier-Stokes equations have been solved in conjunction with $k-{\epsilon}$ model as a turbulence closure. Non-uniformity in flow distribution is assessed for the reference case and parametric studies have been performed for rising channels diameter, Reynolds number and angle between the inlet ports. Also, two different shapes of the inlet plenum namely, rectangular shape and oval shape, have been analysed. The relative flow mal-distribution parameter shows that the flow distribution in the rising channels for the reference case is strongly non-uniform. As the rising channels diameter decreases, the uniformity in the flow distribution as well as the pressure drop inside the inlet plenum increases. Reynolds number is found to have no effect on the flow distribution in the rising channels for both the shapes of the inlet plenum. The increase in angle between the inlet ports makes the flow distribution in the rising channels more uniform.

• Korean Journal of Hydrosciences
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• 제1권
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• pp.49-60
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• 1990

Manning's roughness factor to flow in sand-bed channels may be divided into the grain roughness factor nd the form roughness factor. The grain roughness factor may be dedermined by using Keulegan's formula. By using available experimental data, it was found there is a unique relationship between the form roughness and the hydraulic radius to sediment particle size ratio for a given value of the Froude number. The form roughness and the bed form may be determined by using this unique relationship. The technique for engineering applications of the results appears to be quite simple.

• KSBB Journal
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• 제16권2호
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• pp.146-152
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• 2001

rhGH-GST 융합단백질을 사용하여 재조합 대장균 세포 파쇄액으로부터 직접적으로 내포체의 solid-phase 재접힘을 수행할 수 있는 새로운 공정을 개발하였다. 그것은 고체 업자를 제거하는 동시에 초기에 목적딴백질을 흡착 포집할 수 있 는 expanded bed adsorption 크로마토그래피의 장점을 이용한 것이다. 세포 파쇄액 내 용해훤 내포체로부터의 풀린 융합단백질은 expanded bed adsorption 원리에 의해 STREAMLINE DEAE resin에 흡착되고 세포 찌꺼기 등 고체 입자물들은 위 방향 흐름에 의해 효과적으로 제거된다. Urea를 접차적으로 제거함으로써 융합단백질은 고체 matrix 표면에서 재접힘 된 후 염 놓도 구배에 의해 용출된다. 이 새로운 EBA-mediat$\xi$d 재접힘 방법은 응집현상을 획기적으로 줄이고 공정수율윤 향상시킬 뿐 아나라 공정단계 수를 줄일 수 있다. 이 공정은 우리가 알고 있는 한 세계에서 최초로 개발된 공정이며, 현재 single-chain polypeptide, affinity-tagged protein 등과 갈은 다른 행태의 단백질에 EBA를 사용한 재접힘 공정올 적용시키가 위한 연구가 진행되고 있다.

• 한국병원경영학회지
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• 제11권3호
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• pp.73-93
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• 2006

This study aims at providing necessary informations for management decision-making to the hospital manager, such as ratios of fixed and variable cost to total operating expense, and variable cost ratio to operating revenues, and determinant factors affecting cost behavior. A study model and related hypotheses were established, data were collected from 41 private university hospitals for the 6years from 1998 to 2003, and regression analyses were performed to test the hypotheses. The results of the analyses and conclusions are as follows; First, labor cost and administration cost within the same number of beds have not only fixed quality of the cost, but variable quality of that. Also, the ratio of the variable costs to operating revenue of the metropolitan was estimated 76.9% and that of other area hospitals was 80.1%. Second, the major factors affecting the increase rate of the operating expense were the increase rates of the number of inpatients, the number of employee, and the number of hospital operating bed. This result implies that maintaining a optimal hospital bed size and efficient operation of the beds are important strategic factors of hospital management.

• Journal of Biosystems Engineering
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• 제37권3호
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• pp.155-165
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• 2012

This study was performed to offer the data for design of the seedling bed transfer equipment to make the automation of working process in a plant factory. The seedling bed transfer equipment pushing the seedling bed with bearing wheels on the rail for interconnecting each working process by a pneumatic cylinder was made and examined. The examined transfer force to push the seedling bed with a weight of 178.9 N by the pneumatic cylinder with length of 60 cm and section area of 5 $cm^2$ was measured by experiments. The examined transfer forces was compared with theoretical ones calculated by the theoretical formula derived from dynamic system analysis according to the number of the seedling bed and pushing speed of the pneumatic cylinder head at no load. The transfer function of the equipment with the input variable as the pushing speed $V_{h0}$(m/s) and the output variable as the transfer force f(t)(N) was represented as $F(s)=(V_{h0}/k)(s+B/M)/(s(s^2+Bs/M+1/(kM))$ where M(kg), k(m/N) and B(Ns/m) are the mass of the bed, the compression coefficient of the pneumatic cylinder and the dynamic friction coefficient between the seedling bed and the rail, respectively. The examined transfer force curves and the theoretical ones were represented similar wave forms as to use the theoretical formular to design the device for the seedling bed transfer. The condition of no vibration of the transfer force curve was $kB^2>4M$. The condition of transferring the bed by the repeatable impact and vibration force according to difference of transfer distance of the pneumatic cylinder head from that of the bed was as $Ce^{-\frac{3{\pi}D}{2\omega}}<-1$, where ${\omega}=\sqrt{\frac{1}{kM}-\frac{B^2}{4M^2}}$, $C=\{\frac{\frac{B}{2M}-\frac{1}{kB}}{\omega}\}$, $D=\frac{B}{2M}$. The examined mean peak transfer force represented 4 times of the stead state transfer force. Therefore it seemed that the transfer force of the pneumatic cylinder required for design of the push device was 4Bv where v is the pushing speed.

• 농업과학연구
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• 제5권2호
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• pp.49-55
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• 1978

수도(水稻)의 성묘기계이앙(成苗機械移秧)에 알맞은 건묘(健苗)를 육성(育成)해 내고자 산파식(散播式)인 mat묘(苗)와 조파식(條播式)인 단책묘(短冊苗)의 우열(優劣)을 여러 파종량하(播種量下)에서 비교검토(比較檢討)한 바 다음과 같은 결과(結果)를 얻었다. 1. 20일묘(日苗)에서는 파종양식간(播種樣式間)에 생육상(生育相)과 묘소질(苗素質)의 차이(差異)를 별반 인정(認定)할 수 없었으나 30일묘(日苗)에서는 단책묘(短冊苗)가 mat묘(苗)보다 평균생장속도(平均生長速度)와 상대생장율(相對生長率)이 다같이 크고 묘(苗)의 건물중(乾物重), 탄수화함량(炭水化含量) 및 건물중대초장비율(乾物重對草長比率)도 무겁고 커서 건묘(健苗)의 소질(素質)을 가지고 있었다. 그러나 40일묘(日苗)에서는 그차이(差異)는 축소(縮小)되었으며 묘령(苗令)의 진전(進展)은 거의 인정(認定)할 수 없었다. 2. 묘(苗)의 생장량(生長量)은 박파(薄播)일수록 많고 밀파(密播)와의 차이(差異)는 육묘일수(育苗日數)가 연장(延長)됨에 따라 커졌으며 밀파(密播)의 한계(限界)는 단책묘(短冊苗)에서는 묘상자당(苗箱子當) 200cc이고, mat묘(苗)에서는 250cc 정도(程度)였었다. 3. 단책묘(短冊苗)는 mat묘(苗)보다 초장(草長)과 엽령(葉令)등의 변이계수(變異係數)가 큰 것으로 보아 묘(苗)의 균일성(均一性)은 mat묘(苗)보다 결여(缺如)되는 것 같으며 앞으로 검토(檢討)를 요(要)할 것으로 사료(思料)된다.