• 설비공학논문집
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• 제15권12호
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• pp.1007-1017
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• 2003

An experimental study on the air-side pressure drop and heat transfer coefficient of slit fin-tube heat exchanger has been carried out. The data reduction methodology for air-side heat transfer coefficients in the literature is not based on a consistent approach. This paper focuses on new method of data reduction to obtain the air-side performance of fin-tube heat exchanger using R22 and recommends standard procedures for dry and wet surface heat transfer estimation in fin-tube heat exchanger having refrigerant on the tube-side. Results are presented as plots of friction f-factor and Colburn j -factor against Reynolds number based on the fin collar outside diameter and compared with previous studies. The data covers a range of refrigerant mass fluxes of 150∼250 kg/$m^2$s with air flows at velocity ranges from 0.3 m/s to 0.8 m/s.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.42-47
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• 2007

An analytical method for the free vibration of a flexible rectangular plate in contact with water is developed by the Rayleigh.Ritz method. The plate clamped along the edges is partially contacted with water at both sides. It is assumed that the water bounded by rigid walls is incompressible and inviscid. The wet mode shape of the plate is assumed as a combination of the dry mode shapes of a clamped beam. The liquid motion is described by using the liquid displacement potential and determined by using the compatibility conditions along the liquid interface with the plate. Minimizing the Rayleigh quotient based on the energy conservation gives an eigenvalue problem. It is found that the theoretical results can predict excellently the fluid.coupled natural frequencies comparing with the finite element analysis result.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1849-1852
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• 2005

An automatic cap-washing machine is developed for rinse and dry of synthetic resin cap which is used in spring water bottle. This machine should be achieved all processes washing and drying, array, transfer automatically. A cap is washed by an ozonized water and pure water first. Next, a cap is dried by a hot wind drying equipment. In this paper, structural and modal analysis for the cap-washing machine is carried out to check the design criterion of the machine. The analysis is carried out by FEM simulation using the commercial software, CATIA V5. And a fictitious mass properties was used for the analysis of the machine. Finally, the machine performance is shown to be satisfactory.

• Journal of Chest Surgery
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• 제9권1호
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• pp.41-43
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• 1976

Primary tumors of trachea are rather uncommon, and few cases of direct surgical excision were reported in the literature. Recently we had the opportunity to see a patient with a benign obstructing tumor of the trachea which was confirmed as fibroma. The patient has complained of intermittent dyspnea, especially during inspiratory phase, dry cough and wheezing of a strident character for last 8 years. Bronchoscopy or bronchography were not attempted because of severe dyspnea. Trachea tomogram revealed oval mass at the terminal trachea. The right posterolateral thoracotomy was performed. Tumor, $2.5{\times}1.7cm$ in size, was located at terminal trachea and removed through right lateral tracheotomy without difficulty. Postoperatively all the symptoms and signs disappeared.

• 한국해양공학회지
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• 제23권6호
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• pp.7-11
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• 2009

The dynamic responses and drift forces in waves of a floating circular fish cage are analyzed considering hydroelastic effects. The method of generalized mode is used to calculate the hydroelastic responses of the floater of cage. The elastic mode shapes, generalized mass, and stiffness in dry mode are evaluated by using a structural analysis code. The higher-order boundary element method is adopted to analyze the interaction between fluid and deformable structure. Some results of vertical motions and drift forces are shown and compared with those for a rigid body.

• 한국안전학회지
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• 제12권3호
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• pp.147-154
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• 1997

The main purpose of this study is to investigate the failure surface in a soil mass by a excavation of the model ground. The failure mechanism of an earth structure is usually determined from field failure observations or from laboratory model tests at failure. To study the failure surface for the excavated slope, laboratory model tests were performed by changing the angle of the excavated slope and the ground condition. Results of the laboratory model tests were compared with those obtained with theoretical solutions using limit equilibrium analysis method. The results of model tests show that, there is a failure to create a straight line in the low angle of excavated surface and a create a circle as the angle increases. As the angle of excavated surface is increasing, the angle of the failure surface increases too. In the angle of the failure surface, the submerged ground is less than the dry ground at $3.2^{\circ}$.

• 한국미생물·생명공학회지
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• 제17권6호
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• pp.624-628
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• 1989

A study on the citric acid production using Saccharomycopsis lipolytica (NRRL Y7576) was carried out in shake-flasks, air-lift and membrane recycle bioreactors. The cells entrapped in Ca-alginate beads were used in shake-flasks and air-lift reactor. Repeated batch fermentation in shake-flasks was successfully performed for 34 days and resulted in a yield of 54%. Increased yield (63%) was obtained in the air-lift reactor operation using nitrogen deficient medium (NDM). In the membrane recycle bioreactor operation, the maximal dry cell mass concentration was 39 g/1 at a dilution rate of 0.02 h$^{-1}$ and the yield with NDM was higher than that with growth medium. In addition, the yield and volumetric productivity with pure oxygen supply were greatly improved compared with those with air supply.

• 한국진공학회지
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• 제5권2호
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• pp.169-174
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• 1996

The applications of the high density plasma sources to the etching in semiconductor fabrication process are actively studied because of the more strict requirement from the dry etching process due to shrinking down of the critical dimension. But in the oxide etching with the high density plasma sources, abundant fluorine atoms released from the flurocarbon feed gas make it difficult to get the highly selective $SiO_2/Si$ etching. In this study, to improve the $SiO_2/Si$ etch selectivity through the control of the radical loss channels, we propose the wall heating , one of methods of controlling loss mechanisms. With appearance mass spectroscopy(AMS) and actinometric optical emission spectroscopy(OES), the increase of both radicals impinging on the substrate and existing in bulk plasma, and the decrease of the fluorine atom with wall temperature are observed. As a result, a 40% improvement of the selectivity was achieved for the carbon rich feed gas.

• The Korean Journal of Ecology
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• 제21권4호
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• pp.329-335
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• 1998

The growth of Phytolacca L. grown under three light regimes at three nutrient concentrations was analyzed. The effect of shading treatment on plnat growth was greater than that of nutrient treatment. Plant dry mass increased more than 5-fold during 21 days under 33% and 100% irradiances, whereas that was strongly reduced under 8% irradiance. Net assimilation rate decreased with plant growth irrespective of light and nutrient treatments, though the highest net assimilation rate was shown under 100% irradiance. Under 33% irradiance leaf area in plants supplied with nutrient solution increased to such extent as to compensate reduction in net assimilation rate, whic maintains almost identical growth rate with that under 100% irradiance. The relatonship between total plant nitrogen and leaf nitrogen content was dependent on the growth irradiance. Moreover, leaf nitrogen and specific leaf weight were also changed depending on the light and nutrient conditions. Based on these findings, it is suggested that the adaptive characteristics of Pokeberry plant to light and nutrient conditions may contribute to rapid extension of Pokeberry habital in Korea rocently.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2011년도 추계 학술논문 발표대회
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• pp.27-28
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• 2011

This research aims to secure fundamental data for the development offire-retardant wood by soaking dried wood in fire-retardant liquid. To dry wood, optimal drying conditions for softwood usually used as structural material and hardwood usually used as finishing or furniture material were derived by varying the microwave outputs and heating times of microwave wood drying equipment. The research foundthat each specimen needs 8 to 15 minutes of heating time depending on water content and output. For softwood, fire-retardant liquid equivalent to about 10 percent of the total mass of the specimen infiltrated into the dried wood, of which the water content was reduced to 5~6 percent.