• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.137-140
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• 2007

We consider the optimum air flow channel design for DMFC's in the present study. The effect of pressure drop across the inlet and outlet of a stack on the performance of a DMFC is the optimization of such geometric parameters is crucial to minimize the parasitic power usage by the auxiliary devices such as fuel pumps and blowers. In this paper, we present how the pressure drop control can optimize the driving point of a DMFC stack. Further, we show how the optimal fuel utilization ratio can be achieved, not degrading the performance of DMFC stacks. Overall, we discuss how the flow channel design affects the selection of balance of plant(BOP) components, the design of DMFC systems and the system efficiency.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.351-353
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• 2002

Up to now the design standard of tower for overhead transmission line in KEPCO was revised four times since 1970. During last year. we had reviewed this design standard. This paper shows the design standard of tower for overhead transmission line in KEPCO. In this standard, a kind of tower was defined as standard tower and special tower. Also we had defined usage range of standard tower, tower height, arrangement of power line, design condition of tower arm and etc. On the wind pressure, we had defined basic velocity pressure per region and maximum wind pressure. For special region, design wind pressure will be considered the receded wind velocity of meteorological observatory and regional condition by this standard.

• 대한조선학회지
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• 제52권2호
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• pp.19-24
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• 2015

A reliable assessment and analysis of the condition of high pressure and temperature steam pipelines requires defining stress state, which will take into consideration not just the impact of internal pressure and temperature but all applied loads. For that, usage of modeling and numerical methods for calculation and analysis of stress state is essential. The main aim of piping stress analysis is to check the design of piping layout, which will allow simple, efficient and economical piping supports and provide flexibility to the piping system for loads and stresses. The piping stress analysis is carried out using CAESER II software. By using this software we can evaluate stresses, stress ratios, flange condition, support loads, element forces and displacements at each node and points. In this paper, only the maximum and minimum displacement results are tabulated, which is also shown in detail by an example of main steam pipelines of UST Main Engine System [1].

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.229-233
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• 2002

This paper presents the results of slamming experiment using air pressure cylinder to increase the repeatability of the experiment. When it comes to the slamming experiment, the traditional way of doing it has been the free fall experiment. By adopting air pressure cylinder almost equal peak pressures were obtained with that of free fall experiment. Therefore, the air pressure cylinder can be an alternative tool in slamming experiment.

• 대한소아치과학회지
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• 제25권3호
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• pp.539-544
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• 1998

저자는 열성형재료와 진공성형기를 이용하여 소아치과 임상에서 사용되는 수 종의 장치를 제작하였다. 전공성형기의 구입에 따른 경제적인 부담은 있으나, 기존의 제작법에 비해 제작이 간편하여 시간이 단축될 뿐 아니라 plate 의 두께가 균일하므로 finishing이 거의 필요하지 않으며 더욱 심미적인 장치를 제작할 수 있다. 또한 조직과 접촉하는 부위는 soft한 열성형재료를 사용하여 치아 이동에 유리할 뿐 아니라, 기존의 resin에 비해 불쾌한 맛이 적다는 장점이 있다. Monomer가 없어 조직에 자극이 적고 mutagenous potential이 없으므로 생체 적합성이 뛰어나 조직의 적응이 용이하다. 복잡하거나 특수한 기능 및 견고성이 필요한 악기능교정 장치 등에서는 그 사용이 제한된다는 한계점이 있으나, 소아치과 임상에서 사용되는 대부분의 장치를 쉽고 간편하게 제작할 수 있어 앞으로 임상에서 널리 이용될 수 있을 것으로 생각된다.

• 한국농공학회논문집
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• 제55권6호
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• pp.31-35
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• 2013

This study was carried out to present the pressure drop for various wind speeds through nine types of screens used in horticultural facilities. The screens have been widely used to prevent harmful insects from being entered into agricultural facilities, to reduce strong wind and to shade a light as well. Whatever the usage of the screens was, it was necessary to have good knowledge of how much the screen caused a pressure drop for wind speeds when analyzing both the inner thermal-flow distribution in the facility and the effect of reducing wind speed by using CFD. Furthermore, as for wind screens, the pressure drop for wind speeds was needed as a design load in evaluating the structural stability of the structures supporting the screens. Therefore, the pressure drop through the screens for wind speeds of 5~30 $m{\cdot}s^{-1}$ at about 5 $m{\cdot}s^{-1}$ interval and inflow angles of $0{\sim}45^{\circ}$ at an interval of $15^{\circ}$ was respectively measured in a subsonic wind tunnel. The relation of the pressure drop for various screens was well fitted as a secondorder polynomial expression.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제47권1호
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• pp.15-19
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• 2021

Objectives: The aim of this study was to evaluate correlations between anxiety and preoperative pressure pain assessments and postoperative pain and analgesic requirements in impacted lower third molar tooth surgery. Materials and Methods: This prospective study enrolled 60 patients who underwent impacted lower third molar surgery. The preoperative State-Trait Anxiety Inventory-I (STAI-I), pressure pain threshold, and pressure pain tolerance scores were measured. At 2, 4, 6, 12, and 24 hours, and at 6 days following surgery, the patients scored their pain on the visual analogue scale and recorded their analgesic drug usage. The data were evaluated, and the results were statistically analyzed. Results: Of the 60 patients, 38 were female. Mean age was 24.62±7.42 years. The study found no relationship between preoperative pressure pain assessments and postoperative pain (P>0.05). There was also no relationship observed between preoperative STAI-I scores and postoperative pain (P>0.05). However, there was a positive correlation between operation time and total medication taken (P<0.05). Conclusion: Preoperative pressure pain threshold, pressure pain tolerance, and anxiety level had no significant effects on postoperative pain and analgesic requirements in impacted lower third molar surgery.

• 한국정보시스템학회지:정보시스템연구
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• 제22권3호
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• pp.1-24
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• 2013

SNS(Social Network Services) is being recognized as an important part in our society, individual lives and corporate business aspects, and the influence of SNS is growing explosively as expansion and supply of infrastructures that support mobile environments increase. Previous studies related to SNS were focused on user acceptance of new technology, based on Technology Acceptance Model(TAM). However, they had a limitation to focus on technology acceptance, without the consideration of personal and behavioral factors in SNS use. However, above all, successful SNS requires the understanding of users who are active on the network. Therefore, from the user's perspective, this study attempted a multi-dimensional approach by reflecting characteristics that come from SNS usage. This study considered user innovation, virtual skill, self-efficacy, social pressure and network effect as independent variables, and perceived ease-of-use, perceived usefulness and perceived value as mediating variables, and intention-to-use as dependent variable. The result showed that user innovation, self-efficacy, social pressure and network effect had a significant effect on the mediating variables. The practical contribution of this study is to suggest useful decision alternatives concerned to marketing strategy for acquiring and retaining lone-term customers related to SNS business.

• 한국CDE학회논문집
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• 제19권1호
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• pp.19-28
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• 2014

The filament winding method is widely used to manufacture products of fiber reinforced plastics (FRP), such as high pressure vessels, launch tubes and pipes. For reducing winding time, the method of winding by filament band which consists of several filament fibers is used. NC winding machine is used for precise winding and NC path is needed. Before filament winding, users should verify that winding path which presented by a line is appropriate by filament winding simulation. Also, the used length of each filament is different. So, if the peak filament exhausted, it causes to stop manufacturing. In this research, we developed software which visualizes 3D graphic of filament band winding path and simulates winding process on real time. And we proposed algorithm about calculation of each filament usage. We use geodesic equation for generating filament band surface and calculating the usage length of each filament.

• 한국임상약학회지
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• 제30권4호
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• pp.259-263
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• 2020

Background: Dual-type calcium channel blockers (CCBs), such as efonidipine and cilnidipine, are renoprotective drugs that reportedly reduce proteinuria by dilating afferent and efferent arterioles of the glomerulus. However, studies comparing the effect of dual-type CCB on proteinuria have not been conducted. Therefore, we aimed to compare the effect of dual-type CCB (efonidipine and cilnidipine) usage patterns in hypertensive patients with chronic kidney disease (CKD). Methods: This single-center, retrospective study included 53 patients with CKD who 1) initiated efonidipine or cilnidipine treatment while on a renin-angiotensin system inhibitor and 2) had received efonidipine or cilnidipine for at least one year. We compared usage patterns between the efonidipine and cilnidipine groups during the one-year period and analyzed the following outcomes: urinary protein-to-creatinine ratio, blood pressure, and serum creatinine. Results: The study included 25 patients in the efonidipine group and 28 patients in the cilnidipine group. In both groups, blood pressure and urinary protein-to-creatinine ratios tended to decrease; however, the change during each interval was not significant. Conclusions: In patients with CKD who were on renin-angiotensin system inhibitor therapy, the addition of a dual-type CCB (i.e., efonidipine or cilnidipine) tended to reduce proteinuria; however, the change during each interval was not significant.