• The KSFM Journal of Fluid Machinery
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• v.13 no.5
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• pp.17-21
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• 2010

A volumetric gear pump is often used in extensive industrial applications to provide both high pressure and sufficiently high flow rate by physical displacement of finite volume of fluid with each revolution. To better understand the unsteady flow characteristics within the pump, numerical simulations were conducted by using moving dynamic meshing (MDM) techniques in commercially available CFD software, FLUENT. The effects of rotor clearance size and rotational speed of rotor on the flow characteristics, specially the temporal variation of velocity and pressure field, which is a main source of flow noise, was investigated. The results showed that significant reverse flow is developed in the rotor clearance and that its size is one of the most important factors affecting flow characteristics and pressure pulsation.

• Physical Therapy Korea
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• v.16 no.3
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• pp.1-8
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• 2009

It is important to find the effective position for cough and sputum clearance in respiratory physical therapy. The purpose of this study was to compare the changes in peak expiratory flow (PEF), forced expiratory volume in 1 second ($FEV_1$), and peak cough flow (PCF) related to functional level and measurement position in patients with Duchenne muscular dystrophy. Twenty one subjects were classified into three functional levels, and measurements was undertaken in three different measurement positions (upright sitting, $45^{\circ}$ reclining and supine). Vitalograph PEF/FEV DIARY was used to measure PEF and $FEV_1$, and Ferraris Pocket Peak was used to measure PCF. Mixed two-way analysis of variance and Bonferroni post-hoc test were used for statistical analysis. The results of the study were as follows: 1) Significant main effects for measurement position were found. 2) PEF was the highest in upright sitting, followed by $45^{\circ}$ reclining, and supine in order. 3) $FEV_1$ in upright sitting and $45^{\circ}$ reclining were significantly greater compared with that in supine. 4) PCF in upright sitting and $45^{\circ}$ reclining were significantly greater compared with that in supine. 5) No significant main effects for functional level were found in PEF, $FEV_1$, and PCF. 6) No significant functional level by measurement position interactions were found in PEF, $FEV_1$, and PCF. Therefore, it is concluded that upright sitting and $45^{\circ}$ degree reclining positions are recommended for effective cough and sputum clearance.

• Journal of the Economic Geographical Society of Korea
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• v.9 no.2
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• pp.225-242
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• 2006

This study aims to analyze the spatial distribution pattern of international trade. The method is to analyze the principal components by changing interaction attribute matrix of four dimensions (hinterland, gateway, foreland and commodities) into two dimension matrix. The study area is the territory region of Cheongju clearance depot in inland. The result are as follows : Major spatial patterns of regional connections by hinterland, gateway and foreland are, in the case of exports, ten patterns and in the case of imports come to nine. Composition of major export and import commodities in Cheongju clearance depot are similar, but precision instrument manufactured commodity and nonmetal mineral are remarkable in export and mineral manufactured commodity machinery and electronic manufactured commodity are remarkable in import. Gateway are similar to export and import, but Incheon international airport is used more in the case of import. And Cheongiu international airport is used for some commodities and is remarkable as a foreland of import for the areas outside of Chungcheongbuk-do.

• Advances in Computational Design
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• v.3 no.3
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• pp.233-267
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• 2018

Conventional seismic design of concentrically braced frame (CBF) structures suggests that the gusset plate connecting a steel brace to beams and/or columns should be designed as non-dissipative in earthquakes, while the steel brace members should be designed as dissipative elements. These design intentions lead to thicker and larger gusset plates in design on one hand and a potentially under-rated contribution of gusset plates in design, on the other hand. In contrast, research has shown that compact and thinner gusset plates designed in accordance with the elliptical clearance method rather than the conventional standard linear clearance method can enhance system ductility and energy dissipation capacity in concentrically braced steel frames. In order to assess the two design methods, six cyclic push-over tests on full scale models of concentric braced steel frame structures were conducted. Furthermore, a 3D finite element (FE) shell model, incorporating state-of-the-art tools and techniques in numerical simulation, was developed that successfully replicates the response of gusset plate and bracing members under fully reversed cyclic axial loading. Direct measurements from strain gauges applied to the physical models were used primarily to validate FE models, while comparisons of hysteresis load-displacement loops from physical and numerical models were used to highlight the overall performance of the FE models. The study shows the two design methods attain structural response as per the design intentions; however, the elliptical clearance method has a superiority over the standard linear method as a fact of improving detailing of the gusset plates, enhancing resisting capacity and improving deformability of a CBF structure. Considerations were proposed for improvement of guidelines for detailing gusset plates and bracing members in CBF structures.

• Journal of Korean Clinical Nursing Research
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• v.14 no.3
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• pp.141-151
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• 2008

Purpose: This study aimed at applying a standardized nursing process to adult surgery patients of post anesthetic care unit, and examining the validity of linkages in the measuring index of nursing outcome by which nursing outcome was applied. Method: The subjects were 184 surgery adult patients admitted at the post anesthetic care unit of Y university hospital. This study was used the measured tool developed by Choi et al.(2004) and by Lee (2004) who had already verified a validity based on Johnson and Bulechek's study(2001). Results: The nursing diagnosis of an acute pain, an urinary retention, a nausea, a decreased cardiac output, an ineffective airway clearance and an ineffective airway clearance were used in taking care for patients. The related factors according to the main nursing diagnosis were as the following: an injurious physical factor in an acute pain, reflex are inhibition in an urinary retention, post surgical anesthesia in a nausea, stroke volume change in a decreased cardiac output, secretory stasis in an ineffective airway clearance, pain in an ineffective breathing pattern. Conclusion: The study results could be facilitated in nursing process application for nurses at post anesthetic care unit. Also this study would provide basic data to develop a computerized program for the improvement of nursing process application.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.83-85
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• 2010

A hydraulic gear pump is widely used in many industrial applications to provide both high pressure and high flow rate by physical displacement of finite volume of fluid with each revolution. In this study, two dimensional fluid-structure interaction simulation of gear pump flow was carried out to examine detailed complex flow patterns and structural stress distribution on rotors by using a commercial software ADINA. The effect of rotor clearance size on the flow characteristics, specially the temporal variation of velocity and pressure field, which is a main source of flow noise, also was investigated.

• 한국전산유체공학회:학술대회논문집
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• 1998.05a
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• pp.181-189
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• 1998

A numerical study based on the three-dimensional Reynolds averaged Navier-Stokes equations is presented to analyze the transonic flowfield through two-stage axial compressor. Explicit four-step Runge-Kutta scheme is used for solution algorithm, and local time step and implicit residual averaging are introduced for enhancing the convergency. Artificial dissipation model is adopted to assure the stability of solution. The solver is coupled with Baldwin-Lomax model to describe turbulence. To avoid calculating the unsteady flow, a mixing process is modeled at a station between rotating and stationary blade rows. Results show a variety of important physical phenomena. Comparison of the flowfields with and without tip clearance shows that the effect is considerable in this flowfield. Comparisons with experimental data carried out to validate the calculational results show reasonable agreements. Some remedies are also suggested to improve the revealed problems.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.04a
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• pp.81-85
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• 2000

The present study investigated the processes of selecting and modeling of design variables based on HIEs for developing the evaluational model on the physical suitability of office chairs. Evaluational model can be used for development of the new products or improvement of the old products. For the best utilization of the evaluational model, the process of scrutinizing the variables and the complex interactions among the variables is indispensible. Also, for this, it is necessary to select only the right HIEs which influence the physical suitability of products greatly.The present study suggested analytical processes for making the evaluational model on the physical suitability (Comfortability, Suitability, Stability, Adjustability, Clearance) of office chairs.

• Korean Journal of Ecology and Environment
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• v.39 no.3 s.117
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• pp.390-401
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• 2006

This study was conducted to understand the phytoplankton-zooplankton trophic linkage in Lake Paldang ecosystems (Paldang Dam and Kyungan Stream) from April to December 2005. Zooplankton were filtered as two size groups (microzooplankton (MICZ): 60{\sim}20\;{\mu}m$, macrozooplankton (MACZ): >$200\;{\mu}m$), and their clearance rates and C-fluxes on phytoplankton were measured. Grazing experiments were performed in the laboratory with the different zooplankton densities (0, 2, 4, 8x of ambient density, n=2). Diatoms, such as Aulacoseira and Cyclotella were dominant phytoplankton taxa at both sites. Among phytoplankton communities, total carbon biomass of phyflagellates was much higher than others at both sites. Rotifers numerically dominated zooplankton community, while cladocerans dominated carbon biomass. Both phytoplankton and zooplankton density and biomass were high in spring, but decreased markedly after summer monsoon season. plankton biomass at Kyungan Stream was significantly higher than that of Paldang Dam. Zooplankton clearance rate and amount of C-flux were relatively high in the spring and then decreased after summer at both sites. Seasonal change of C-flux was similar to that of zooplankton biomass (P<0.001, n=7). MACZ clearance rate and C-flux were higher than those of MICZ. Water residence time and physical disturbance in summer appeared to affect zooplankton grazing on phytoplankton at the study sites. Our results indicate phytoplankton were an important energy source for zooplankton in Lake Paldang ecosystem. Furthermore, C-flux of plankton food web is affected by not only biological components but also physical parameters.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1B
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• pp.83-90
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• 2009

This study describes the characteristics of distribution of lift-force acting under pier deck through physical experiment. The shape of peak wave pressure was sharp when compressed air existed but was not sharp without that. Values of lift-force was different between edge point and center point in the same block. Distribution of lift-force was expressed differently owing to dimensionless of deck length (l/L), wave steepness (H/L), clearance height per wave height (D/H). The dimensionless factor of D/H affected on the lift-force the clearance between still water surface and decks. This decided the maximum of lift-force. In the case of the same values of D/H, the lift-force are changed by the wave steepness (H/L). Because (D/H) become smaller as the wave steepness (H/L) is increased the height of decks must be decided with the condition which don't have the clearance with $D_{max}$ for the stable design of deck of pier. Effect of reducing lift force was greater in the on-shore than the off-shore according to compressed air existence. This researches points out that design of deck should retain compressed air in order to reduce wave lift force.