• 한국태양에너지학회 논문집
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• 제32권4호
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• pp.9-16
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• 2012

Nanofluids using Carbon Nanotubes have a excellent thermal characteristic. In this study, for increasing the efficiency of solar collector, the thermal conductivity and viscosity of Ethanol-Oxidized Multi-walled Carbon Nanofluids were measured. Nanofluids were manufactured by ultra-sonic dispersing Oxidized Multi-walled Carbon Nanotubes(OMWCNTs) in ethanol at the rates of 0.0005 ~ 0.1 vol%. The thermal conductivity and viscosity of manufactured nanofluids were measured at the low temperature($10^{\circ}C$), the room temperature($25^{\circ}C$) and the high temperature($70^{\circ}C$). For measuring thermal conductivity and viscosity, we used transient hot-wire method and rotational digital viscometer, respectively. As a result, under given temperature conditions, thermal conductivity of the 0.1 vol% nanofluids improved 33.74% ($10^{\circ}C$), 33.14% ($25^{\circ}C$) and 32.36% ($70^{\circ}C$), and its viscosity increased by 37.93% ($10^{\circ}C$), 31.92% ($25^{\circ}C$) and 29.42% ($70^{\circ}C$) than the base fluids.

• 한국해양공학회지
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• 제30권6호
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• pp.505-519
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• 2016

If the seabed is exposed to high waves for a long period, the pore water pressure may be excessive, making the seabed subject to liquefaction. As the water pressure change due to wave action is transmitted to the pore water pressure of the seabed, a phase difference will occur because of the fluid resistance from water permeability. Thus, the effective stress of the seabed will be decreased. If a composite breakwater or other structure with large wave reflection is installed over the seabed, a partial standing wave field is formed, and thus larger wave loading is directly transmitted to the seabed, which considerably influences its stability. To analyze the 3-D dynamic response characteristics of the seabed around a composite breakwater, this study performed a numerical simulation by applying LES-WASS-3D to directly analyze the wave-structure-soil interaction. First, the waveform around the composite breakwater and the pore water pressure in the seabed and rubble mound were compared and verified using the results of existing experiments. In addition, the characteristics of the wave field were analyzed around the composite breakwater, where there was an opening under different incident wave conditions. To analyze the effect of the changed wave field on the 3-D dynamic response of the seabed, the correlation between the wave height distribution and pore water pressure distribution of the seabed was investigated. Finally, the numerical results for the perpendicular phase difference of the pore water pressure were aggregated to understand the characteristics of the 3-D dynamic response of the seabed around the composite breakwater in relation to the water-structure-soil interaction.

• 드라이브 ㆍ 컨트롤
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• 제12권1호
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• pp.1-8
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• 2015

The stability of friction characteristics and thermal management for a dry type dual clutch transmission (DCT) are inferior to those of a wet clutch. Too high temperature resulting from frequent engagement of DCT speeds up degradation or serious wear of the pressure plate or burning of the clutch disk lining. Even though it is significantly important to estimate the temperature of a dry double clutch (DDC) in real-time, few meaningful study of the thermal model of DDC has been known yet. This study presented a thermal analytical model of lumped parameters for a DDC by analyzing its each component firstly. Then a series of experimental test was carried out on the test bench with a patented temperature telemetry system to validate the proposed thermal model. The thermal model, whose optimal parameter values were found by optimization algorithm, was also simulated on the experimental test conditions. The simulation results of DDC temperature show consistency with the experiment, which validates the proposed thermal model of DDC.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제29권1호
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• pp.42-49
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• 2007

Infections in oral and maxillofacial region are relativley common and self-limiting, but in some cases, infections spread to adjacent hard and soft tissue and to cause any complication, even threaten life. So we made retrospective study of patients with interfascial infection who had been hospitalized and been treated by surgical treatment in Dankook university about 10 years. We reviewed the charts of patient with interfascial infection from 1995 to 2005. The result were as follows: 1. In gender & age distribution, male(54.2%) & fouth decade were most frequently. 2. The most common cause of infection was dental caries(55.2%) and the most of involving teeth was lower posterior teeth(44.1%). 3. Submandibular space is most frequently involving space and most infection involved mainly one space. 4. The patients with systemic disease were 38.2%. Diabetic mellitus was 87.2% of systemic diease. The admission period was 19.5 days in systemic disease. 5. The most microorganism in culture was Streptococcus Viridans(36.2%) in all patient. Klebsiella Pneumoniae was found most in Diabetic Mellitus. 6. The patient were mainly treated I&D on admission day. Of them 5(1.1%) patients were received tracheostomy. 7. Serum albumin, CRP and body weight are associated with Nutritional Risk Index(NRI). High risk patient group according to NRI classification showed higher rate of complications & mortality. 8. The patients with complication were 28(6.7%) persons. 4(0.9%) patients were expired. Nutritional Risk Index was helpful to predict the prognosis. When interfascial infection starts to spread, we must pay attention to airway management. Fluid therapy with nutritional may support to healing of wound.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제41권4호
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• pp.181-189
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• 2015

Objectives: The purpose of this study was to compare the microbial and clinical effects of mechanical debridement (MD) alone or in combination with the application of enamel matrix derivative (EMD) and sustained-release micro-spherical minocycline (MSM) for treatment of peri-implant mucosal inflammation (PIMI). Materials and Methods: Subjects with at least one implant with PIMI were included and divided into control and two different test groups. In all three groups, MD was performed. In the MSM group, following MD, MSM was placed subgingivally around the implants. In the EMD group, after MD, EMD was placed in the sulcus around the implants. Sampling of peri-implant crevicular fluid for microbial analysis with real-time polymerase chain reaction and recording of probing depth (PD) and bleeding on probing (BOP) were performed prior to as well as two weeks and three months after treatment. Median values and interquartile range were estimated for each variable during the various assessment intervals of the study. Results: In all groups, at two weeks and three months, the counts of Porphyromonas gingivalis decreased significantly compared to baseline. Levels of P. gingivalis were significantly reduced in MSM (P<0.001) and EMD (P=0.026) groups compared to the control group. Also, clinical parameters improved significantly at two weeks and three months. Reduction of PD was significant in MSM (P<0.001) and EMD (P<0.001) groups. The decrease in BOP in the MSM, EMD, and control groups was 60%, 50%, and 20%, respectively. Conclusion: The use of MSM and EMD can be an adjunctive treatment for management of PIMI and improves clinical parameters and reduces P. gingivalis burden three months after treatment.

• 대한영양사협회학술지
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• 제23권1호
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• pp.27-38
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• 2017

Maintaining adequate fluid balance is essential for all biological functions in the body. The purpose of this study was to evaluate vulnerability to dehydration by analyzing age, gender, body mass index (BMI), and blood lipid parameters in health checkup examinees who visited Sahmyook Seoul Hospital for comprehensive health checkups. In a binary logistic regression analysis stratified by age and body mass index the odd ratio for dehydration was as high as 3.317 (95% CI: 1.666~6.605) in the 50s age group, 4.224 (95% CI: 2.038~ 8.755) in the 60s age group, and 4.610 (95% CI: 1.943~10.940) in the above 70s age group compared to 20s reference age group. Aged females showed greater vulnerability to dehydration with significance levels of P<0.01 and P<0.001. Compared to a normal weight (BMI: 18.5~22.9) the odd ratio was higher in males with an under weight (BMI: less than 18.5) (5.130 [95% CI: 1.631~16.132]) and in females with an over weight (BMI: 23.0~24.9) (1.500 [95% CI: 1.065~2.114]). In conclusion, our results showed that vulnerability to dehydration increased with age and was higher in under weight males and over weight females than that in normal weight.

• Wind and Structures
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• 제14권4호
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• pp.285-300
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• 2011

Researchers at the International Hurricane Research Center (IHRC), Florida International University (FIU), are working in stages on the construction of a large state-of-the-art Wall of Wind (WoW) facility to support research in the area of Wind Engineering. In this paper, the challenges of simulating hurricane winds for the WoW are presented and investigated based on a scale model study. Three wind profiles were simulated using airfoils, and/or adjustable planks mechanism with and without grids. Evaluations of flow characteristics were performed in order to enhance the WoW's flow simulation capabilities. Characteristics of the simulated wind fields are compared to the results obtained from a study using computational fluid dynamics (CFD) and also validated via pressure measurements on small-scale models of the Silsoe cube building. Optimal scale of the test model and its optimal distance from the WoW contraction exit are determined - which are two important aspects for testing using an open jet facility such as the WoW. The main objective of this study is to further the understanding of the WoW capabilities and the characteristics of its test section by means of intensive tests and validations at small scale in order to apply this knowledge to the design of the full-scale WoW and for future wind engineering testing.

• 한국수자원학회논문집
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• 제44권6호
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• pp.439-447
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• 2011

This study aims to test the feasibility of combined use of EFDC (Environmental Fluid Dynamics Code) hydrodynamic model and WASP7.3 (Water Quality Analysis Program) model to improve accuracy of water quality predictions of the Yongdam Lake, Korea. The orthogonal curvilinear grid system was used for EFDC model to represent riverine shape of the study area. Relationship between volume, surface and elevation results were checked to verify if the grid system represents morphology of the lake properly. Monthly average boundary water quality conditions were estimated using the monthly monitored water quality data from Korean Ministry of Environment DB system. Monthly tributary flow rates were back-routed using dam discharge data and allocated in proportion to each basin area as direct measurements were not available. The optimum number of grid system was determined to be 372 horizontal cells and 10 vertical layers of the site for 1 year simulation of hydrodynamics and water quality out of iterative trials. Monthly observed BOD, TN, TP and Chl-a concentrations inside the lake were used for calibration of WASP7.3 model. This study shows that EFDC and WASP can be used in series successfully to improve accuracy in water quality modeling. However, it was observed that the amount of data to develop inflow water quality and flow rate boundary conditions and water quality data inside lake for calibration were not enough for accurate modeling. It is suggested that object-oriented data collection systems would be necessary to ensure accuracy of EFDC-WASP model application and thus for efficient lake water quality management strategy development.

• 대한약침학회지
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• 제12권2호
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• pp.67-75
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• 2009

Objectives : This study was performed to developing orally administered analgesics and locally injected pharmacopuncture analgesics like opioids. Methods : Literary investigation on the origin of poppy (Papaver somniferum L) and other narcotics was conducted to examine the potential of developing orally administered analgesics and locally injected pharmacopuncture analgesics. Opium is a gum-like mass derived from air-dried white fluid of immature fruit of the poppy. Opium contains approximately 20 types of alkaloids including morphine, codeine, thebaine, papaverine and others. Natural opioids and synthetic alkaloid derivatives are the constituents of opioid analgesics and their effects and side-effects depend on the peculiarities of receptors. An extreme caution is required in the selection of proper dosage, proper analgesic types, and indications for successful pain management. Results and Discussion : With the enactment of "Narcotic control protocol", herbs such as cannibis and poppy are no longer available for use by Korean medicine doctors, and these doctors are faced with difficulty in managing severe pain in the clinical environment. A systematic consideration is inevitable for overcoming the limitation on these analgesics.

• 한국산학기술학회논문지
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• 제14권3호
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• pp.1519-1526
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• 2013

본 연구에서는 현장조사를 통해 주물 제조 사업장의 일부 용해공정에 적용되고 있는 캐노피 후드(canopy hood)의 흡인 성능을 검토하였다. 또한, CFD model을 이용하여 유해대기오염물질 포집 능력을 향상시킬 수 있는 방안들을 대한 유동장 및 압력장을 비교 및 평가하였다. Case-2(플랜지 부착+이중 후드)의 경우 포집 성능 측면에서는 개선이 가능하지만 후드 정압이 기존 구조보다 약 70% 이상 증가할 것으로 예측되어 현장 적용성이 좋지 않을 것으로 나타났다. 흡인효율을 개선하기 위해서는 case-3(플랜지 부착+이중 콘 부착)의 형상이 가장 적합할 것으로 판단된다. 이는 개구부 중앙에 이중 콘(cone)이 설치되어 후드 가장자리로 유량을 집중시킬 수 있으며, 또한 후드 중앙으로 상승되는 흄(hume)은 콘의 기울기에 의해 정압 상승의 요인 없이 제어할 수 있기 때문이다.