• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권6호
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• pp.520-530
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• 2006

Undifferentiated mesencymal stem cells(UMSCs) have been thought to be multipotent cells that can replicate as undifferentiated cells and that have the potential to differentiate into lineages of mesenchymal tissue including the bone, cartilage, fat, tendon, muscle, and marrow stroma. It can be used to sinus lifting, Guided bone regeneration, other bone graft in dental part. The purpose of this study is to evaluate the effect of mesencymal stem cells on sinus augmentation with autogenous bone, fibrin glue mixture in a rabbit model. 8 New Zealand white rabbits were divided randomly into 4 groups based on their time of sacrifice(1, 2, 4 and 8 weeks). First, undifferentiated mesenchymal stem cells were isolated from iliac crest marrow of rabbits and expanded in vitro. cell culture was performed in accordance with the technique described by Tsutsumi et al. In the present study, The animals were sacrificed at 1, 2, 4 and 8 weeks after transplantation, and the bone formation ability of each sides was evaluated clinically, radiologically, histologically and histomorphologically. According to the histological observations, Stem cell group showed integrated graft bone with host bone from sinus wall. At 2 and 4weeks, It showed active newly formed bone and neovascularization. At 8 weeks, lamella bone was observed in sinus graft material area. Radiologically, autobone with stem cell showed more radiopaque than autobone without stemcell. there were significant differences in bone volume between 2 and 4 weeks (p<0.05). In summary, the autobone with stem cells had well-formed, newly formed bone and neovasculization, compared with the autobone without stem cells (esp. 2 weeks and 4 weeks) The findings of this experimental study indicate that the use of a mixture of mesenchymal stem cell yielded good results in osteogenesis and bone volume comparable with that achieved by autogenous bone. Therefore, this application of this promising new sinus floor elevation method for implants with tissue engineering technology deserves further study.

• 한국해안·해양공학회논문집
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• 제21권1호
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• pp.30-38
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• 2009

최근에 해안구조물의 시공에 있어 친수성 및 방재 기능을 동시에 갖는 구조물이 검토되는 사례가 증가하고 있다. 본 연구의 목적은 비교적 급한 1:5 사면을 가진 해안구조물 위로 전파하는 파랑변형 및 파의 처오름을 예측하는 것이다. 사면 위의 파랑변형 및 처오름을 해석하기 위하여 비선형 천수방정식을 사용하였으며, 투수층 내의 유체운동에는 확장형 Forchheimer의 저항법칙에 근거한 비선형, 비정상 Darcy법칙을 적용하여 규칙파 및 불규칙파를 대상으로 수행되었고, 계산결과는 PBREAK 수치모델의 적용성 및 한계성을 검토하기 위하여 수리모형실험 결과와 비교검토 되었다. PBREAK 수치모델은 사면 위의 파형의 변화를 잘 예측하였으나 질량 및 운동량의 교환이 많이 발생하는 쇄파대 내에서 수리모형실험 결과와 약간의 차이를 보여주었다. 또한 수심평균된 수립자 유속은 파봉 부근을 제외하고 파곡 아래에서 계측한 실험치와 잘 일치하였다.

• 한국수자원학회논문집
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• 제42권7호
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• pp.559-569
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• 2009

환경 및 경제적 문제 등으로 인해 댐과 같은 대규모 수공구조물의 신설이 점차 어려워짐에 따라, 천변저류지 등과 같은 소규모 수공구조물의 설치가 대안으로 검토되고 있다. 천변저류지와 같은 소규모 수공구조물의 경우 홍수량, 유입수문곡선, 천변저류지 용량 및 월류위어의 월류고 등에 따라 홍수저감효과가 민감하게 반응하므로, 대상 저류지의 제원 결정을 위해 목표하는 설계빈도 결정이 선행되어야 한다. 또한 천변저류지를 이용하여 목표하는 홍수저감효과를 얻기 위해 다수의 천변저류지가 설치되어야 하며, 즉 천변저류지군의 홍수조절효과는 이들 저류지군을 연계한 수문네트워크의 분석에 의해 산정되어야 한다. 본 연구에서는 설계빈도 변화에 따른 천변저류지군의 홍수저감효과를 산정해 보았으며 산정된 홍수저감효과를 분석하여 천변저류지의 최적위치를 선정하기 위한 새로운 지수를 제안하였다. 천변저류지의 최적위치를 결정하기 위해 개발된 기존의 의사결정모형을 보완하여 제안된 지수를 산정하기 위한 모형을 개발하였으며, 개발된 모형을 안성천유역에 적용하여 기존의 연구결과와 비교하고, 적용성을 검토하였다. 그 결과 천변저류지 최적위치를 결정하기 위한 기준으로의 활용이 가능한 것으로 판단되었다.

• 한국농공학회지
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• 제12권4호
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• pp.2078-2083
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• 1970

The purpose of this study is to give the data neccesary for improving the planning of drainage structures, specially inverted siphons, in irrigation channels. With the samples of 15 drainage inlets, one drainage flume, 16 drainage inverted siphons and 6 drainage culverts in the 3 lines of irrigation channel under Chong-Won Irrigation Association, author abtained the following results. 1. It is presumed that design drainage discharge should be determined with some additional reserves, on the basis of the maximum rainfall intensity in local area and the size of drainage area on the topographical map, avoiding the way of eye measure. 2. Location of drainage inlet should be kept away from the place where topography can make lots of wash load, but when unavoidably allowing the inflow into irrigation channel, wash load outlet with even the purpose of drainage, or drainage flume in stead of drainage inlet should be taken account of. 3. It is presumed that drainage flume may be the structure which can perform its function from a structural point of view as far as topography permits. 4. Drainage inverted siphon should be avoided at any place as much as possible; a) In case that location of the siphon would be permitted only at paddy field, drainage area hauing the amount of discharge which requires more than 90cm in diameter could only be allowed. b) In this case, crest elevation of the tank of both inlet and outlet, at least, should not be lower than the surface level of paddy field. c) As far as topography and stratum permit, ratio of depth of outlet tank to head drop should be decreased as much as possible so that discharging efficiency of wash load could increase. d) In case of avoiding the setting of the siphon, irrigation aqueduct, irrigation inverted siphon, or drainage flume should be recommended in accordance with topography. 5. Discharging capability of wash load by drainage culvert appeared to depend hardly upon the diameter of the culvert, but greatly upon the location, specially near village, for there stones and dirts dumped may considerably be piled up. So, a counter plan for that is required.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권1호
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• pp.19-27
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• 2008

Thirty-six sinus grafts were performed in 34 patients with an alveolar crest bone height in the posterior maxilla of 3 to 5 mm before grafting. The sinuses were grafted using Bio-Oss alone or mixed with fibrin glue. Group 1 was the control group and included 25 patients who received a xenograft mixed in saline. Group 2 comprised 9 patients who received a xenograft and fibrin glue. The study was further subdivided at the time of 9 months. This histologic study evaluated by hematoxylin-eosin (H&E) and histomorphometric analysis whether fibrin glue in combination with Bio-Oss enhances bone regeneration in sinus floor elevation in humans. The new bone formation was better in Group 2 than in Group 1, but the difference was not significant. The absorption of the graft material was faster in Group 2 than in Group 1, in the short term, but better in Group 1 over the long term, although the difference was not significant. Lamellar bone was formed earlier in Group 1 compared to Group 2, but the difference was not significant. Overall, the surgery site stabilized earlier with new bone formation in Group 2 than in Group 1, but the difference was not significant. Combining a fibrin sealant and Bio-Oss could lead to improved scaffolds for bone tissue engineering based on the synergistic effects of the biomaterials. Therefore, Bio-Oss or Bio-Oss plus Tisseel may be used depending on the situation.

• 한국해안·해양공학회논문집
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• 제35권3호
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• pp.49-56
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• 2023

해안구조물 설계시 허용평균월파량은 설계요소 중의 하나이며, 구조물의 마루높이는 구조물의 안전, 보행자의 안전 및 운영 등에 요구되는 월파량 이하가 되도록 하여야 한다. 본 연구에서는 경사식구조물의 기하학적 형상을 고려하고, 다양한 수심조건에서 평균월파량 계측을 위한 2차원 수리실험을 수행하였다. 수리실험은 서로 다른 파형경사, 상대여유고, 상대파고 등을 적용하여 수행되었다. 실험결과를 이용하여 경사식구조물의 평균월파량을 산정할 수 있는 경험식을 제안하였다.

• 한국농공학회지
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• 제20권1호
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• pp.4592-4598
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• 1978

The purpose of this research is to find out mathemetically an economical intake water depth in the design of head works through the derivation of some formulas. For the performance of the purpose the following formulas were found out for the design intake water depth in each flow type of intake sluice, such as overflow type and orifice type. (1) The conditional equations of !he economical intake water depth in .case that weir body is placed on permeable soil layer ; (a) in the overflow type of intake sluice, {{{{ { zp}_{1 } { Lh}_{1 }+ { 1} over {2 } { Cp}_{3 }L(0.67 SQRT { q} -0.61) { ( { d}_{0 }+ { h}_{1 }+ { h}_{0 } )}^{- { 1} over {2 } }- { { { 3Q}_{1 } { p}_{5 } { h}_{1 } }^{- { 5} over {2 } } } over { { 2m}_{1 }(1-s) SQRT { 2gs} }+[ LEFT { b+ { 4C TIMES { 0.61}^{2 } } over {3(r-1) }+z( { d}_{0 }+ { h}_{0 } ) RIGHT } { p}_{1 }L+(1+ SQRT { 1+ { z}^{2 } } ) { p}_{2 }L+ { dcp}_{3 }L+ { nkp}_{5 }+( { 2z}_{0 }+m )(1-s) { L}_{d } { p}_{7 } ] =0}}}} (b) in the orifice type of intake sluice, {{{{ { zp}_{1 } { Lh}_{1 }+ { 1} over {2 } C { p}_{3 }L(0.67 SQRT { q} -0.61)}}}} {{{{ { ({d }_{0 }+ { h}_{1 }+ { h}_{0 } )}^{ - { 1} over {2 } }- { { 3Q}_{1 } { p}_{ 6} { { h}_{1 } }^{- { 5} over {2 } } } over { { 2m}_{ 2}m' SQRT { 2gs} }+[ LEFT { b+ { 4C TIMES { 0.61}^{2 } } over {3(r-1) }+z( { d}_{0 }+ { h}_{0 } ) RIGHT } { p}_{1 }L }}}} {{{{+(1+ SQRT { 1+ { z}^{2 } } ) { p}_{2 } L+dC { p}_{4 }L+(2 { z}_{0 }+m )(1-s) { L}_{d } { p}_{7 }]=0 }}}} where, z=outer slope of weir body (value of cotangent), h1=intake water depth (m), L=total length of weir (m), C=Bligh's creep ratio, q=flood discharge overflowing weir crest per unit length of weir (m3/sec/m), d0=average height to intake sill elevation in weir (m), h0=freeboard of weir (m), Q1=design irrigation requirements (m3/sec), m1=coefficient of head loss (0.9∼0.95) s=(h1-h2)/h1, h2=flow water depth outside intake sluice gate (m), b=width of weir crest (m), r=specific weight of weir materials, d=depth of cutting along seepage length under the weir (m), n=number of side contraction, k=coefficient of side contraction loss (0.02∼0.04), m2=coefficient of discharge (0.7∼0.9) m'=h0/h1, h0=open height of gate (m), p1 and p4=unit price of weir body and of excavation of weir site, respectively (won/㎥), p2 and p3=unit price of construction form and of revetment for protection of downstream riverbed, respectively (won/㎡), p5 and p6=average cost per unit width of intake sluice including cost of intake canal having the same one as width of the sluice in case of overflow type and orifice type respectively (won/m), zo : inner slope of section area in intake canal from its beginning point to its changing point to ordinary flow section, m: coefficient concerning the mean width of intak canal site,a : freeboard of intake canal. (2) The conditional equations of the economical intake water depth in case that weir body is built on the foundation of rock bed ; (a) in the overflow type of intake sluice, {{{{ { zp}_{1 } { Lh}_{1 }- { { { 3Q}_{1 } { p}_{5 } { h}_{1 } }^{- {5 } over {2 } } } over { { 2m}_{1 }(1-s) SQRT { 2gs} }+[ LEFT { b+z( { d}_{0 }+ { h}_{0 } )RIGHT } { p}_{1 }L+(1+ SQRT { 1+ { z}^{2 } } ) { p}_{2 }L+ { nkp}_{5 }}}}} {{{{+( { 2z}_{0 }+m )(1-s) { L}_{d } { p}_{7 } ]=0 }}}} (b) in the orifice type of intake sluice, {{{{ { zp}_{1 } { Lh}_{1 }- { { { 3Q}_{1 } { p}_{6 } { h}_{1 } }^{- {5 } over {2 } } } over { { 2m}_{2 }m' SQRT { 2gs} }+[ LEFT { b+z( { d}_{0 }+ { h}_{0 } )RIGHT } { p}_{1 }L+(1+ SQRT { 1+ { z}^{2 } } ) { p}_{2 }L}}}} {{{{+( { 2z}_{0 }+m )(1-s) { L}_{d } { p}_{7 } ]=0}}}} The construction cost of weir cut-off and revetment on outside slope of leeve, and the damages suffered from inundation in upstream area were not included in the process of deriving the above conditional equations, but it is true that magnitude of intake water depth influences somewhat on the cost and damages. Therefore, in applying the above equations the fact that should not be over looked is that the design value of intake water depth to be adopted should not be more largely determined than the value of h1 satisfying the above formulas.

• 한국습지학회지
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• 제15권4호
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• pp.573-583
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• 2013

기후변화에 의한 홍수 특성의 변화에 적극적으로 대처하기 위한 대규모 댐 건설의 추진이 환경성, 경제성 등과 같은 문제로 난해해 짐에 따라 강변저류지 또는 유수지 시설이 유역내 홍수 분담 측면에서 포함되기 시작하였다. 강변저류지는 주하도에 인접되고 제방으로 둘러쌓인 공간으로 홍수기에 월류구조물을 통하여 인위적으로 범람시키는 지역이다. 강변저류지 직하류에서의 홍수저감효과는 설계홍수수문곡선의 형상, 강변저류지의 저류용량 등에 추가하여 월류부 구조물의 형식, 길이 및 월류턱 표고에 따라 영향을 받는다. 본 연구는 표본지구인 청미천에서 주어진 수문곡선에 관하여 월류제 형식과 수문 형식에 따른 홍수저감효과를 비교코자 하였다. 월류부에서 수문형식이 월류제 형식보다 홍수저감효과가 더 크지만 수문형식에 의한 홍수저감율은 공학적 견지에서 보면 의미있는 수치가 아니기 때문에 수문형식을 선정할 때는 초기사업비, 운영 관리 비용 등을 신중히 고려해야 하는 것으로 분석되었다.

• 한국수자원학회논문집
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• 제43권2호
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• pp.139-151
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• 2010

횡월류식 강변저류지를 포함하는 하천수계의 흐름 모의를 위한 준2차원 부정류 계산모형을 수립하였다. 수립된 모형은 횡월류 흐름에 대해서는 수량보존에 관한 연속방정식 및 월류형 수위-유량 관계식을, 하도에 대해서는 1차원 St. Venant 방정식을 각각 지배방정식으로 하여 흐름을 모의하는 폐합형 계산모형이다. 수립된 모형을 현재 계획 중인 군남 홍수조절지부터 한강 합류 지점까지의 임진강 구간에 대하여 적용하였다. 횡월류 위어의 유량계수에 대한 민감도 분석 결과, 최대유량 및 수위의 저감효과는 유량계수에 관계없이 거의 일정한 것으로 나타났다. 수계 하류 측에 위치한 강변저류지일수록 배수영향이 커지므로 첨두 홍수위의 감소효과는 줄어드는 것으로 모의되었다. 강변저류지의 홍수저감 효과는 조도계수에 따라 크게 달라지며 횡월류 위어의 정부표고가 높을수록 조도계수에 따른 홍수조절 효과의 불확실성이 커지는 것을 알 수 있었다. 강변저류지의 설계를 위해서는 조도계수의 적절한 추정과정이 선행되어야 함은 물론이고, 추정된 조도계수의 불확실성을 감안하여 횡월류 위어의 정부표고를 결정하기 위한 방법의 개발이 필요할 것으로 판단된다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권5호
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• pp.405-418
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• 2007

Mesenchymal stem cells(MSCs) have been though to be multipotent cells that can replicate that have the potential to differentiate into lineages of mesenchymal tissue including the bone, cartilage, fat, tendon, muscle, and marrow stroma. Especially, scaffolds to support cell-based tissue engineering are critical determinants of clinical efforts to regenerate and repair the body. Selection of a matrix carrier imvolves consideration of the matrix's role as a scaffold for physical support and host tissue integration as well as its ability to support of synergize the osteoinductive program of the implanted mesenchymal stem cell. The aim of this study is to evaluate the effect of autobone and Bio-$Oss^{(R)}$ to adherent mesenchymal stem cells as scaffolds on sinus augmentation with fibrin glue mixture in a rabbit model. 16 New Zealand White rabbits were divided randomly into 4 groups based on their time of sacrifice(1, 2, 4 and 8 weeks). First, mesenchymal stem cells were isolated from iliac crest marrow of rabbits and expanded in vitro. Cell culture was performed in accordance with the technique described by Tsutsumi et al. In the present study, the animals were sacrificed at 1, 2, 4 and 8 weeks after transplantation, and the bone formation ability of each sides was evaluated clinically, radiologically, histologically and histomorphologically. According to the histological observations, autobone scaffolds group showed integrated graft bone with host bone from sinus wall. At 2 and 4 weeks, it showed active newly formed bone and neovascularization. At 8 weeks, lamellae bone was observed in sinus graft material area. Radiologically, autobone with stem cell showed more radiopaque than Bio-$Oss^{(R)}$ scaffolds group. there were significant differences in bone volume between 4 and 8 weeks(p<0.05).