• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.5
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• pp.257-264
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• 2016

In this study, experiments for measurements of entrainment rate of fluid mud were carried out using annular flume domestically for the first time. Six entrainment tests using kaolinite sediments were conducted with different initial concentrations of fluid mud. It is shown that sediment settling counteracts the otherwise buoyancy dependent entrainment of fluid mud, and that the settling effect leads to a measurably decreased entrainment rate at higher Richardson numbers in comparison with entrainment of salt water, due to additional dissipation of turbulent kinetic energy in the interfacial layer. Through the comparison with previous other studies, the overall performance of the annular flume, the experimental procedure and the test results in simulating the entrainment of fluid mud are shown to be good enough to verify.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.1
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• pp.26-33
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• 1992

Physical experiments were conducted to investigate the suspension properties of silty mud in combined wave-current flow. Suspension mass when there was opposing current was much higher than that when there was following current. It is due to the fact which strong turbulent flow in the bottom is developed in the opposing current but oscillatory flow effect decreases in the following current. Critical bed shear stress for suspension of silty mud in combined wave-current flow was deduced to be $\tau$$_{c}$～0.045 N/$m^2$. Formulas expressing the relation with initial suspension rate with bed shear stress, and the relation between the former and measured significant wave height were deduced. The relationship of initial suspension rate with bed shear stress was significantly scattered, but the relationship with measured significant wave height was reasonably good. When there is wave only, vertical diffusion coefficients of sediment were calculated from the vertical concentration gradients of suspended sediment when the concentration of suspended sediment approached to nearly equilibrium state. The diffusion coefficient increased exponentially with height from the bottom in the lower half of the flow depth but were nearly constant in the upper half of the flow depth.h.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.126-127
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• 2023

현대사회에 유행처럼 자리잡은 웨이트 트레이닝의 부상률이 높은 것으로 확인되었다. 가장 큰 부상 원인은 '무리한 동작'으로 자신이 수행할 수 있는 운동강도를 인지하지 못하여 근력 유지가 되지 않아 발생한다. 이러한 문제를 해결하기 위하여 근력 유지 실패를 일으키는 원인인 '근피로도'를 검출하여 개인에게 적합한 운동 강도를 찾는 연구를 진행하였다. 그 결과, MNF 기울기 분석을 통해 운동 반복횟수가 증가함에 따라 근피로도가 커지는 것을 확인하였다. 향후, 잡음에 강한 매개변수를 바탕으로 연구가 이어진다면 웨이트 트레이닝의 부상률이 낮아질 것으로 사료된다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.6
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• pp.462-469
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• 2009

This study suggests a general formula of non-cohesive sediment transport rates for waves and currents which is also valid for wave only or current only condition. On-offshore sediment transport rates with the second order Stokes wave in the shallow water are calculated as the pickup rate times the distance. The formula depicts reasonably that high waves move material offshore, and low waves move material onshore. Also the formula, as is the case the waves with long period tend to move material onshore, shows good results.

• Korean Journal of Ichthyology
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• v.21 no.3
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• pp.158-166
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• 2009

To obtain the fundamental data for the mass seedling production of grunt, Hapalogenys nitens, we investigated the influence of salinity and cold water temperature on hatching and survival of eggs and growth and survival of larvae and fry. In regards to salinity, we surveyed the hatching rate and floating rate of fertilized eggs, the floating rate and survival rate of hatching larvae, and the survival and growth of fry. In respect to cold temperature, we investigated the influence of degree of daily temperature decrease, acute temperature shock, and slow temperature decreases on the survival, feeding and swimming activities of fry. In the salinity experiment, the hatching and floating rates of fertilized eggs, and the floating and survival rates of hatching larvae, were shown to be higher in seawater than in brackish water. Growth and survival of larvae and fry were not different between seawater (25~32 psu) and brackish water (5~20 psu), but were significantly lower in freshwater. In the cold-temperature test, three tests showed that rearing of fry in cold water and acutely decreasing water temperature to less than $10^{\circ}C$ reduced the survival, feeding and swimming activities of the fry. Therefore, we concluded that low salinity (less than 32 psu) could reduce the hatching rate and survival of eggs, but the growth and survival of fry were not influenced by salinity, and cold water (less than $10^{\circ}C$) decreased metabolism of grunt. During winter, we found a low-temperature limit at $8^{\circ}C$.

• The Optical Journal
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• s.124
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• pp.33-35
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• 2009

우리나라 디스플레이산업은 수년간 세계시장점유율 1위를 지속하고 있을 뿐만 아니라 수익성 측면에서도 경쟁국을 압도하여 산업내 글로벌 포지션을 후발자에서 선발자로 변화시킨 성과를 달성했다. 우리니라 디스플레이산업은 호황기에는 최고의 수익률을 시현하고 불황기에는 최소 적자로 빠른 흑자전환 모습 을 보임으로써, 세계시장점유율과 수익성의 양 측면에서 경쟁국들을 압도했다. 이러한 디스플레이산업의 경쟁력 강화와 세계시장 지배력의 확대는 경기침체기 혹은 경제위기 극복 이후 우리나라 제조업의 글로벌 경쟁력 강화를 위한 새로운 발전모델로 부상하고 있음을 시사한다. 본 고에서는 산업연구원의 '경기침체기의 디스플레이산업, 제조업의 새로운 발전모델로 부상' 이라는 보고서를 통해 디스플레이산업이 주목받게 된 요인을 살펴보고 국내 제조업이 나아가야 할 방향에 대해 알아본다.

• Journal of Aquaculture
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• v.10 no.4
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• pp.463-472
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• 1997

Floating and hatching rates, size and survival activity index(SAI) of spawned eggs of red spotted grouper, Epinephelus akaara were studied to understand egg qualities during the spawning periods in 1992, 1993 and 1995. The fish spawned from mid-July to mid-August when temperature ranged 23~$28^\circC$. Floating, fertilization and hatching rates were higher in the eggs from early to middle than those from late during the spawning period. SAI ranged 1.8~9.6, and it was closely related to survival rate until mouth operning time (SMOT). Egg diameter decreased gradually with the time of spawning, while diameter of oil globule was constant during the spawning periods. Induced spawnings were carried out with one injection of HCG over 5, 000 IU/kg body weight. Floating, fertilization and hatching rates of the induced spawning eggs were higher than those of untreated ones. Thus, induced spawning method with HCG was recommended for collecting fertilized eggs in bulk. Optimal time for the collection of high quality eggs was supposed to be from early to middle during the spawning periods. Considering that egg qualities were vulnerable within the period, hatchability, incidence of malformed larvae, SMOT and SAI were factors to be considered together to get good quality of eggs.

• 건강소식
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• v.30 no.2 s.327
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• pp.12-13
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• 2006

일반적으로 아이들은 어른보다 활동적인 경향이 있어 적절한 체력수준을 유지한다. 그러나 해부학적, 생리학적, 심리학적으로 미성숙하기 때문에 운동프로그램을 고안할 때 특별한 주의가 필요하다.아이들을 위한 운동프로그램에서 가장 중요한 것이 안정성이다. 아이들은 신체활동 시 부상률이 높고, 지구성운동이 과할 경우 골단성장판을 다칠 수 있기 때문에 더욱 안정에 유의한다. 또한 아이들은 성인에 비해 열자극에 적응하는데 상대적으로 무력하므로 온도가 높은 여름날 야외에서 운동할 경우, 물을 많이 섭취하게 하고 자주 휴식을 취하도록 한다.

• Journal of the Korean Orthopaedic Association
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• v.56 no.5
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• pp.433-439
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• 2021

The definitive and effective method for tetanus prevention has contributed to decreased incidence and mortality of tetanus infections in developed countries. On the other hand, there has been a recent increase in incidence due to the lack of awareness of the disease and lack of adherence to preventive measures. Tetanus infections can be fatal. Therefore, prevention must be the utmost priority, followed by aggressive surgical management along with supportive care. The authors present a case of a 59-year-old male patient diagnosed with a generalized tetanus infection from a foot injury. The patient recovered successfully after aggressive surgical debridement and amputation of the infected toe at the metatarsal level, followed by two months of supportive care.

• Journal of Aquaculture
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• v.20 no.4
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• pp.219-225
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• 2007

This study investigated the correlationship between artificial maturation season and reproduction coefficient of cultured eel Anguilla japonica from May (spring) to next January (winter). The brood stock, female eels ($400{\sim}600\;g$) were artificially matured by weekly intramuscular injections of salmon pituitary extracts (SPE, 20 mg/fish) to induce a completion of vitellogenesis. After completion of vitellogenesis, final oocyte maturation and ovulation was induced by injection of $17{\alpha}$, $20{\beta}-dihydroxyprogesterone$ (DHP) at about $2\;{\mu}g/g$ body weight. Most fish ovulated $15{\sim}18\;h$ following the DHP injection. The ovulated fish were induced to natural spawning or artificial fertilization by the dry method. Males ($200{\sim}350\;g$) were received weekly intramuscular injections of human chorionic gonadotropin (HCG) at a dosage of 1 IU/g body weight to induce testicular maturation and spermiation. Seasonal reproduction coefficient which includes the rate of ovulation, buoyancy, fertilization and hatching of eggs in the artificially matured eel during spring to summer ($May{\sim}July$) were significantly higher than the other season, while there were no significant difference among spring and summer (P<0.05). Furthermore, the number of eggs spawned and larvae hatched in the artificially maturated eel during spring to summer ($May{\sim}July$) were significantly higher than the other season, while there were no significant difference in spring and summer (P<0.05). These results indicate that artificial maturation by hormone treatment of A. japonica was successful only during spring to summer, which is the maturation period in the wild stock in nature. Consequently, it is possible to determine the period of artificially induced sexual maturity by the reproduction coefficient which includes the rate of ovulation, buoyancy, fertilization and hatching of eggs in the cultured eel A. japonica.