• The KSFM Journal of Fluid Machinery
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• v.10 no.6
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• pp.44-49
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• 2007

In this paper, effects of inlet shape on the performance of a submerged cargo pump were numerically studied using a commercial CFD code CFX. The inlet shape, especially the gap between pump and suction well, is an important parameter in a point of view of performances of submerged cargo pump due to its effects on the residual and also hydraulic performance of the pump, respectively. To know the optimized gap, the overall performance degradations were calculated with the gap. In addition to that, the flow field through the gap was investigated to explain the effect of velocity non-uniformity on the performance of the pump impeller.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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• pp.63-69
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• 2022

Compressor efficiency must be improved to reduce refrigerator power consumption. In this study, the heat dissipation rate through the compressor housing is increased via gap flow passages between the compressor body and housing. Four types of gap flow passages are considered for achieving the maximum heat-dissipation rate. In addition, thermal analysis is performed to examine the effect of increased heat dissipation rate on the energy efficiency ratio (EER). The results show that the heat dissipation rate, compressor superheat, and compressor EER increased by up to approximately 52%, 3 ℃, and approximately 1%, respectively.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.2
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• pp.233-238
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• 2014

Purpose : The Varian's Eclipse radiation treatment planning system is able to correct radiation treatment thought leaf gap which is limitation MLC movement for collision with both MLC. In this study, I'm try to analyze dosimetric effect about the leaf gap in treatment planning system. And then apply to clinical implement. Materials and Methods : The Elclipse version is 10.0. In general, the leaf gap set to 0.05~0.3 mm and must measurement each leaf gap. The leaf gap measured by each LINACs and photons. We applied to measured each leaf gap in IMRT and VMAT. Changing the leaf gap, we evaluated treatment plans by Dmax, CI, etc. Results : When the same plan was evaluated with changing the leaf gap, an increase of 2-5% over the value Dmax, CI increases mm to 0.0~0.50 mm leaf gap. Volumetric modulated and intensity modulated radiation therapy plans all showed the same trend was not found significant between each radiation treatment planning. Conclusion : Generally, the leaf gap setting has a unique measure of the Multileaf collimator. However, the aging of the Multileaf collimator, calibration, and can be changed, after inspection and repair of the lip gap should eventually because these values affect the treatment plan must be applied to the treatment after confirmation. In some cases, may be to maintain the initial setting value of the lip gap, which is undesirable because it can override the influence on the treatment plan.

• Journal of the Korean Data and Information Science Society
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• v.26 no.6
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• pp.1377-1386
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• 2015

GDP gap is closely related with economic activity of a country as a whole, especially with the economic fluctuations which is called business cycle. GDP gap is regarded as an important variable for the monetary policy of the central bank because it provides information on the excess demand pressures and employment matters. However, GDP gap may not provide enough information of the effect of recent economic structural change or the environmental change of domestic and external economic condition. In this paper, the GDP is decomposed by statistical filtering techniques and various models are fitted to estimate the influence of GDP gap on Inflation and see if it has been changed. Analysis results show that the influence of GDP gap on inflation decreased in the 2000s while that of global GDP gap increased. These results also support that recent low inflation rate is due to the change of overseas economic condition, such as a slowdown in exports resulting from the global recession, as well as domestic factors.

• Journal of Korean Society of Steel Construction
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• v.19 no.4
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• pp.345-355
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• 2007

During winter, the CWR (continuous welded rail) may be broken when a temperature drop below the neutral level changes the axial force, causing tensile fracture and creating a rail gap. The passage of a train on a rail with an open gap may lead to very costly derailments. In this paper, the use of a track-and-train-coupled model whose rail has an open gap is proposed for dynamic interaction analysis. Linear track and train systems were coupled in this study by a nonlinear Herzian contact spring, and the complete system matrices of the total track-train system were constructed. Moreover, the interaction phenomenon considering the presence of an open gap in the rail was toughly defined by assigning the irregularity functions between the two sides of the gap. Time history analysis, which has an iteration scheme such as the Newmark-$\beta$ method (based on the Modified Newton-Raphson methods), was conducted to solve the nonlinear equation. .Finally, numerical studies were conducted to assess the effect of the various parameters of the system when applied to various speeds, open-gap sizes, and support stiffnesses of the rail.

• Journal of Korean Neurosurgical Society
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• v.49 no.1
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• pp.13-19
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• 2011

Objective: The purpose of this study is to investigate the combined effects of ginkgo biloba extract, ginkgolide A and B and aspirin on SK-N-MC, human neuroblastoma cell viability and mRNA expression of growth associated protein43 (GAP43), Microtubule-associated protein 2 (MAP2), B-cell lymphoma2 (Bcl2) and protein53 (p53) gene in hypoxia and reperfusion condition. Methods: SK-N-MC cells were cultured with Dulbecco's Modified Eagle's Medium (DMEM) media in $37^{\circ}C$, 5% $CO_2$ incubator. The cells were cultured for 8 hours in non-glucose media and hypoxic condition and for 12 hours in normal media and $O_2$ concentration. Cell survival rate was measured with Cell Counting Kit-8 (CCK-8) reagent assay. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to estimate mRNA levels of GAP43, MAP2, Bcl2, and p53 genes. Results: The ginkgolide A and B increased viable cell number decreased in hypoxic and reperfused condition. The co-treatment of ginkgolide B with aspirin also increased the number of viable cells, however, there was no additive effect. Although there was no increase of mRNA expression of GAP43, MAP2, and Bcl2 in SK-N-MC cells with individual treatment of ginkgolide A, B or aspirin in hypoxic and reperfused condition, the co-treatment of ginkgolide A or B with aspirin significantly increased GAP43 and Bcl2 mRNA levels. In MAP2, only the co-treatment of ginkgolide A and aspirin showed increasing effect. The mRNA expression of p53 had no change in all treating conditions. Conclusion: This study suggests that the combined treatments of Ginkgo biloba extracts and aspirin increase the regeneration of neuroblastoma cells injured by hypoxia and reperfusion.

• Toxicological Research
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• v.26 no.1
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• pp.29-35
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• 2010

The present study was conducted to investigate the antimutagenic potential of the methanolic extract from the leaves of sweet potato (Ipomea batatas, IB) with the SOS chromotest (umu test) and Salmonella typhimurium TA 98 and TA 100. The anticarcinogenic effects were also studied by calculation of the $IC_{50}$ on human cancer cell lines and investigating the function of gap junction in rat liver epithelial cells. The IB extract inhibited dose-dependently the ${\beta}$-galactosidase activity induced spontaneously at concentration of more than 200 mg/ml in S. typhimurium TA 1535/pSK 1002, and decreased significantly (p < 0.01) the ${\beta}$-galactosidase activities induced by mutagen 6-chloro-9-[3-(2-chloroethylamino)proylamino]-2-methoxyacridine dihydrochloride (ICR) at dose of more than 0.4 mg/0.1 ml. The IB extract showed no effect on the spontaneous reversions of S. typhimurium TA 98 and 100 but benzo(${\alpha}$)pyrene (BaP)-stimulated reversions were decreased dose-dependently (p < 0.01) at the concentration of more than 100 mg/ml. The $IC_{50}$ value of stomach cancer cells was lower than that of normal rat liver epithelial cells, but the values of colon and uterine cancer cell lines were similar to those of normal rat liver epithelial cells. The transfer of dye through gap junctions was not affected by treatment of the IB extracts at any concentration during treatment periods. The simultaneously treatment of IB extract and 12-O-tetradecanoylphorbol-13-acetate (TPA) effectively prevented the inhibition of dye transfer induced by TPA 1 hour after treatment at all exposed concentrations. The number of gap junctions was significantly (p < 0.01) increased by the treatment with IB extract at concentrations of more than 40 ${\mu}g$/ml. The inhibition of the expression of gap junction proteins by TPA (0.01 ${\mu}g$/ml) was recovered dose dependently by the simultaneous treatment of IB extracts. Our data suggest that Ipomea batatas has antimutagenic and anticarcionogenic activity in vitro.

• Journal of Applied Tourism Food and Beverage Management and Research
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• v.17 no.2
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• pp.1-26
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• 2006

The life of modern society is going to be more scientific and rationalized. According to these trends, our dietary life was also dramatically changed. Family restaurants grew up by 30% every year was became the place of meeting and relaxation from the place of selling and eating. These demands request to improve an atmosphere, a facility and a service in family restaurants. The objective of the present study is to investigate the effect of the gap of service in family restaurant on customer loyalty based on Oliver's gap theory. These results could be contributed to make the strategy of marketing in family restaurants. The purpose of this study in detail is as below. First, it is determined the difference of its expectation and its outcome regarding on the family restaurant service. Second, it is investigated the relationship of the gap of family restaurant with customer satisfaction. The suggestions of the present study are as below. First, it is necessary to get a novel CI strategy to clean the environment of restaurant and to induce the customer desires for young females as a dominant customers. Second, it is need to improve the interior of restaurant and to develop foods for optimal dietary environments. Third, based on the customer loyalty of the present study, customer satisfaction belongs to optimal dietary environment and utilization, whereas the negative gap of service is commercial dietary goods and employee's service. Therefore, the continuous loyalty along with personal satisfaction intends to improve the maximized atmosphere and utilization on use. The main strategy of marketing could be focused on the improvement of commercial dietary goods and utilization for the satisfaction and demands of customers.

• Applied Science and Convergence Technology
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• v.23 no.5
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• pp.248-253
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• 2014

Air Gap Membrane Distillation (AGMD) is one of several technologies that can be used to solve problems fresh water availability. AGMD exhibits several advantages, including low conductive heat loss and higher thermal efficiency, due to the presence of an air gap between the membrane and condensation wall. A previous study by Bhardwaj found that the condensation surface properties (materials and contact angle) affected the total collected fresh water in the solar distillation process. However, the process condition differences between solar distillation and AGMD might result in different condensation phenomena. In contrast, N. Miljkovic showed that a hydrophobic surface has higher condensation heat transfer. Moreover, to the best of our knowledge, there is no study that investigates the effect of condensation surface properties in AGMD to overall process performance (i.e. flux and thermal efficiency). Thus, in this study, we treated the AGMD condensation surface to make it hydrophobic or hydrophilic. The condensation surface could be made hydrophilic by immersing and boiling plate in deionized (DI) water, which caused the formation of hydrophilic aluminum hydroxide (AlOOH) nanostructures. Afterwards, the treated plate was coated using hexamethyldisiloxane (HMDSO) through plasma-enhanced chemical vapor deposition (PECVD). The result indicated that condensation surface properties do not affect the permeate flux or thermal efficiency significantly. In general, the permeate flux and thermal efficiency for the treated plates were lower than those of the non-treated plate (pristine). However, at a 1 mm and 3 mm air gap, the treated plate outperformed the non-treated plate (pristine) in terms of permeate flux. Therefore, although surface wettability effect was not significant, it still provided a little influence.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.3
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• pp.237-244
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• 2011

An experimental study was carried out to investigate the effect of the inclination angle on the nucleate pool boiling of saturated water at atmospheric pressure. We considered an annulus with a gap of 5 mm and a bottom opening. The inner tube of the annulus was heated, and the outer diameter and the length of the tube were 25.4 mm and 500 mm, respectively. The inclination angle was varied from horizontal to vertical. The results were compared to those for an annulus with a larger gap and a single tube. In the small-gap annulus, the effect of the inclination angle on the heat transfer was not significant. However, an early onset of the critical heat flux was observed at 80 kW/$m^2$ when the annulus was horizontal. Liquid agitation and bubble coalescence were considered to be the major heat-transfer mechanisms.