• 순환기질환의공학회:학술대회논문집
• /
• 2005.12a
• /
• pp.25-26
• /
• 2005

동맥경화의 재발생 위치는 속도와 전단응력 등과 같은 혈류역학의 인자들의 영향을 많이 받는 혈관형태를 가진 영역이다. 이러한 결과는 관상동맥에 동맥경화의 발생빈도를 조사한 결과와 일치하고 있으며, 즉 좌전 하행지, 회선지, 및 우관동맥 등의 동맥경화성 병변 발생빈도에서 좌전하행지가 가장 많은 빈도를 나타낸다. 따라서 동맥경화의 발생 및 재형성은 혈관의 동맥경화성 위험지역의 형태적 특징, 즉, 분지부의 위치, 길이, 각도의 변화 등에 따라 달라질 수 있음을 시사한다. 동일한 관상동맥이더라도 동맥경화의 발생이 용이한 형태가 있는데, 혈관의 형태학적 특성에 따란 혈류역학적 특성이 달라지고 동맥경화가 발생할 수 있는 가능성이나 진행과정이 차이가 날 수 있음을 말한다. 특히 임계치를 넘는 고전단응력은 혈관내피세포를 파괴하거나 손상을 주며, 반대로 임계치 미만의 저전단응력은 혈류의 정체시간을 길게 하여 양쪽 모두 동맥경화성 생물학적 반응을 유발 할 수 있며, 고전단응력과 저전단응력의 빈번한 맥동성 변화작용으로 혈관이 손상될 수 있는 한계범위를 넘어서게 될 때 내피세포의 방어체계를 파괴시키거나 혈관성형술후의 신내포세포 형성과정에서 생물학적 활성반응을 촉진하게 되는 환경을 제공하게 되어 동맥경화를 촉진한다고 할 수 있다. 즉 임계치 이상의 고전단응력이 나타나는 형태와 입구경계조건이 발생되면 내피세포 손상에 따른 혈전 현상의 발생가능성이 높아지며, 임계치 미만의 저전단응력이 발생되면 동맥경화성 죽상반 재형성에 영향을 미치게 한다. 결론적으로 동맥경화의 재발생의 기전은 변형된 혈관의 형태학적인 차이와 위치에 따라 서로 다른 혈류역학적 유발할 수 있는 물리적 환경을 제공하는 데에서 출발한다고 할 수 있다.$8.0{\sim}8.3$으로 알카리 쪽으로 이동하였다. 파일롯트 규모로 본 고정화 효소 충전탑(내경 30cm, 높이 85cm)에 의한 이성화당의 생산을 시도하였던바, 고정화 효소(350 IXIU/ml-R) 1리터가 30일동안에 약 293리터의 이성화당을 생산할 수 있는 것으로 나타났다.l plane에서 선수군(選手群)이 $62.7{\pm}7.36^{\circ}$로서 비선수군(非選手群)과 별(別) 차이(差異)가 없었고, horizontalplane에서는 선수군(選手群)이 $-23.5{\pm}7.2^{\circ}$로서 비선수군(非選手群)의 $-38.8{\pm}8.2^{\circ}$에 비(比)해 유의(有意)하게 높았으며 운동후(運動後) 양군(兩群) 모두 유의(有意)하게 높았다. QRS vector 길이에서 Frontal plane에서 선수군(選手群)이 $13.86{\pm}1.44\;mm$로서 비선수군(非選手群)의 $9.62{\pm}0.97\;mm$에 비(比)해 유의(有意)하게 높았으며 운동후(運動後)에도 유의(有意)하게 높았다. Horizontal plane에서도 선수군(選手群)이 $19.82{\pm}2.10\;mm$로서 비선수군(非選手群)의 $16.90{\pm}1.39\;mm$에 비(比)해 유의(有意)하게 높았고 운동후(運動後)에도 선수군(選手群)이 유의(有意)하게 높았다. 이상(以上)을 종합(綜合)해 보면 선수군(選手群)의 R파고(波高)가 비선수군(非選手群)에 비(比)해 운동후(運動後) 계속(繼續) 유의(有意)하게 높았고, $Rv_5$

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.2 no.3
• /
• pp.255-264
• /
• 2014

This study analyzes the cause and the repairing method of water leak by parts of basement parking lot which is recorded to have a high defect frequency in apartment buildings. It has been assessed that the cause of water leakage on the first floor upper substrate is due to such factors as landscaping and weights. During construction or through other cases, it has been determined that cracks were produced in the apartment structure because the structure was weak and exposed to the effects of the substrate movement. The base floor and underground external walls are areas that are exposed to water pressure (uplife pressure), thus in normal cases the rear surface repair of the structure using sythetic rubberized polymer gel should be considered as an effective method. However, in cases where application of waterproofing layer is required in the structure due to high water pressure, using asystolic cement milk grout to form the waterproofing layer and applying water-swelling acrylic material into the cracked areas is considered to be highly effective.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.36 no.1
• /
• pp.114-118
• /
• 2009

Sialolithiasis is the formation of calcific concretions within the ductal system of major or minor salivary glands. The submandibular gland is most involved because of its high viscosity of the saliva and the long, curved duct. It may occur at any age but, it is most common in middle-aged adults and rare in childhood. Clinical symptoms in sialolithiasis are variable but, swelling is the most common, followed by the pain. Clinical examination and radiographic examination(panoramic and mandibular occlusal radiographs, sialography, intraoral-, extraoral- ultrasound, CT scan, MRI and sialoendoscopy) can help to confirm a diagnosis and localize a stone. The treatment is surgical intervention, either removal of the sialolith or sialoadenectomy. However, non-invasive techniques including shock-wave lithotripsy, $CO_2$ laser and endoscopic treatment used in selected cases. A 5-Year-old girl referred from private practice for evaluation of a yellowish mass on the floor of the mouth. She complained that it had became three times bigger than four months ago when it was found for the first time and she had some pain on submandibular gland area occasionally. On physical examination, a firm and yellowish mass could be seen at the orifice of the submandibular duct. Diagnosis is the submandibular sialolithiasis in the anterior Wharton`s duct. Under local anesthesia, stone was removed.

• Journal of the Korean Electrochemical Society
• /
• v.8 no.4
• /
• pp.155-161
• /
• 2005

In this paper, commercial CFD program FLUENT v5.3 is used for simulation of MCFC stack. Besides using conservation equations included in FLUENT by default, mass change, mole fraction change and heat added or removed due to electrochemical reactions and water gas shift reaction are considered by adding several equations using user defined function. The stacks calculated are 6 and 25 kW class coflow stack which are composed of 20 and 40 unit cells respectively. Simulation results showed that pressure drop took place in the direction of gas flow, and the pressure drop of cathode side is more larger than that of anode side. And the velocity of cathode gas decreased along with the gas flow direction, but the velocity of anode gas increased because of the mass and volume changes by the chemical reactions in each electrodes. Simulated temperature profile of the stack tended to increase along with the gas flow direction and it showed similar results with the experimental data. Water gas shift reaction was endothermic at the gas inlet side but it was exothermic at the outlet side of electrode respectively. Therefore water gas shift reaction played a role in increasing temperature difference between inlet and outlet side of stack. This results suggests that the simulation of large scale commercial stacks need to consider water gas shift reaction.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.13 no.3
• /
• pp.209-229
• /
• 2001

Simultaneous field measurements of short-period and long-period waves were made at five stations inside or outside Okkye Harbor, which is located in the east coast of Korea. Based on the measured data, spacial and temporal variations of the long-period wave energy were examined. Three smoothing methods were examined for the spectral estimates: fixed interval averaging method, incremental interval averaging method, and moving averaging method. It was shown that a proper smoothing method should be chosen depending on the period of first resonant mode and the length of data being used. By comparing the results obtained using the long-term data with those obtained using two-day data, we showed that it is necessary to analyze the data of calm seas and storm seas separately. The Helmholtz resonant period in Okkye Harbor was found to be about 9.6 minutes with its relative amplification ratio of 9 to 10, and local amplifications were apparent at the periods of 1.2 to 1.3 minutes and 0.7 minute. During calm seas, both at the harbor entrance and inside the harbor the energy of the waves of 9 minutes or longer period was larger than the infra-gravity wave energy by more than 100 times. However, during storm seas the energy level was very high all over the period band, and local amplification was larger than that during calm seas by more than 100 times, especially inside the harbor, Finally it was shown that the energies of the Helmholtz resonant mode and the infra-gravity waves of 1 to 2 minutes are proportional to the storm wave height.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.28 no.1
• /
• pp.7-14
• /
• 1995

As a part of the multidisciplinary oceanographic study for the productivity enhancement in Deukryang Bay, temperature and salinity were observed from 1992 through 1993. From the results, only the data in summer of two years are compared. Owing to the contrary meteorolgical conditions in both summers both of temperature and salinity had the patterns of horizontal distributions quite different from each other. In 1992 with low precipitation, there was a tendency of temperature increase and salinity decrease from the bay mouth towards the bay head. In 1993 when the air temperature was abnormally low, isotherms and isotherms tended to be parallel to the local u3s of the bay where the warmer and less saline water distributed along the western coast. Reduced solar radiation and increase in the relative importance of the distribution of properties along the current that was parallel to the axis of the bay could be responsible for this result. Vertical structures of both temperature and salinity were dependent on the stirring effect of tidal current. Stratification was destroyed during the spring tide while it was formed during the neap tide.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.1
• /
• pp.762-768
• /
• 2015

This study examined the integration value of a low level pilotis space, a component that has been often selected as an essential planning element of the recent high-rise apartment complex, and compared the main outdoor unit spaces with that of an average integration value of the individual complexes. Furthermore, this study provided the preliminary data for the next level of research, which is the observation of the pilotis space usage behaviors and the frequency of utilization. The results of this present research are as follows. First, from the main outdoor unit spaces of the high-rise apartment complexes including the pilotis space, a 'complex entrance' or a 'plaza' space showed the highest integration value. Second, the spatial integration value of a pilotis space in a high-rise apartment complex was generally lower that of the integration value of other main outdoor units. Third, from the pilotis spaces of the high-rise apartment complex, those with a 'projecting entry access + pilotis addition type' that did not provide an access to the individual units, had the lowest space utilization rate by the inhabitants; thus, had a high likelihood of the spaces becoming used for illegitimate activities or becoming vacant.

• Journal of Chest Surgery
• /
• v.30 no.3
• /
• pp.263-269
• /
• 1997

From April 1987 to May 1996, 13 infants underwent a Norwood operation for complex congenital heart diseases including hypoplastic left heart syndrome (n : 7), mitral stenosis with small VSD and subaortic stenosis (n : 1), mitral atresia with ventricular septal defect, coarctation of aorta, and subaortic stenosis (n = 1), interrupted aortic arch with ventricular septal defect and subaortic stenosis (n : 1), tricuspid atresia with transposition of the great arteries (n = 1), and complex double-inlet left ventricle (n : 2). All patients without hypoplastic left heart syndrome were associated wit hypoplasia of ascending aorta and arch. Age at operation ranged from 3 days to 8.7 months (mean 60.6 $\pm$ 71.6 days, median 39 days). The operative mortality( < 30 days) was 46% (6 patients). Late mortality was 15% (2 patients). All operative deaths occured during the Erst 24 hours after the operation as a result of cardiopulmonary bypass weaning failure (5 patients) and sudden hemodynamic instability postoperatively (1 patient). Late death was due to aspiration pneumonia in two cases. There are 5 long-term survivals (39%). Three of them have undergone a two-stage repair with a modified Fontan operation in two and total cavopulmonary shunt in one at 12, 17, 4.5 months after Norwood procedure with no mortality. Two patients have entered a three-stage repair strategy by undergoing a bidirectional cavopulmonary shunt at 3 and 5.5 months after initial operation with 1 operative death. The actuarial survival rate for all patients at the first-stage operation, including hospital deaths and ate death was 30.8% at 1 year. In conclusion, the operative mortality of Norwood operation was relatively high compared to other operation for major cardiac anomalies, continuing experience will lead to an improvement in result.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.17 no.1
• /
• pp.68-80
• /
• 1984

Garolim Bay is not only important fishing ground but also expected area for the tidal power plant. The construction and operation of tidal power plant will make change the ecosystem of this bay. Therefore, the actual fisheries stocks should be precisely understood for the effect estimation and overall utilization of the bay after the construction of the tidal power plant. During the study period from January through December in 1981, forty-six adult fishes species, 3 species of fish egg and 25 fishes larvae species have occurred in the bay. Considering the result on monthly distribution of eggs and larvae, the inner area of the bay seems to be important as nursing ground of larvae spawned at the outside bay in winter, e. g., Ammodytes personatus, and Enedrias sp. This inner bay is also major spawning ground for many species spawning in spring and summer, e. g., Gobiidae, Konosirus punctatus, Engraulis japonica, etc. Taking into consideration the annual mean production for three years($1978{\sim}1980$), there are two major fishing seasons. The one is in May-June for Enedrias larvae stock, and the another in October-November for big eyed herring stock. For the mariculture stocks, short necked clam, oyster and laver are important species. After construction of the tidal power plant, the migratory species, i. e., larvae of Enedrias and Ammodytes personatus, Mugil cephalus, Konosirus punctatus, etc. will be directly damaged by the interuption of migration route. On the otter hand, the change of physico-chemical factors of seawater will also affect the ecosystem of the bay. Consequently, for the overall utilization of the bay after construction, the actual ecosystem including the fisheries stocks, must bs precisely revealed, and the mechanical designs, e. g., sluice position and its demension, should be also considered with these biological characters of the bay.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.4
• /
• pp.270-274
• /
• 2016

The effect of the rib angle-of-attack on heat transfer in the convergent channel with ${\vee}/{\wedge}$-shaped ribs was examined experimentally. Four differently angled ribs (a = $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, and $90^{\circ}$) were placed to only the one sided wall. The ribbed wall was manufactured with a fixed rib height (e) of 10 mm and rib spacing (p)-to-height (e) ratio of 10. The convergent channel had a length of 1,000 mm and a cross-sectional areas of $100mm{\times}100mm$ at inlet and $50mm{\times}100mm$ at exit. The measurement was conducted for the Reynolds numbers ranging from 22,000 to 75,000. The results show that the Nusselt number is generally higher at higher Reynolds number and that an angle-of-attack of $45^{\circ}$ at the ${\wedge}$-shaped rib produces the greatest Nusselt number.