• 대한기계학회논문집
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• 제18권6호
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• pp.1551-1558
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• 1994

An experiment was conducted to investigate whether an equation of heat transfer coefficient derived form energy equation of two-phase plug flow can be actually applied to the industrial field. The heat is constantly transfered to the sand beds from the wall of heat exchanger while the sand moves down through cylindrical heat exchanger by gravity from feed hooper. To increase heat transfer, turbulators such as glass ball and steel pipe packings were used. In addition, the experiment in the case of fluidizing the sand beds was also carried out. The temperatures of the sand beds and the wall were measured along the heat exchanger axis. The density and porosity of the sand beds were also measured. The deviations of the mean velocity of sands from the velocity on the wall surface because of the slip conditions on the wall were negligible (within 3%). The heat transfer coefficients when the turbulators were used and when the sand beds were fluidized were found to be much greater than those of the plain plug flow.

• 대한기계학회논문집
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• 제8권6호
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• pp.591-598
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• 1984

본 논문에서는 고체상호간 미끄름접촉에 의해 발생하는 진동과 소음의 특성을 조사하기 위해서 실험과 이론해석을 행하였다. 미끄름접촉과 관련된 소음에는 brake squeal 혹은 wheel screech등과 같이 stick-slip 형태의 동적 불안정 상태와 관련이 있는 squeal noise와, 겉보기로 동적 안정 상태에 있으나 미끄름접촉면간에 내재하는 미끄름접촉 고유의 불규칙한 동특성에 기인하여 발생하는 rubbing noise가 있다. 본 연구의 대상은 보다 기본적인 형태인 후자에 한한다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.154-158
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• 2009

The vortex ventilation system (VV) which uses a rotating finned swirler installed coaxially with the exhaust duct is a very effective local ventilator. VV can enhance the capture depth by a factor of 3-5 compared to the conventional exhaust hood, in the absence of any solid walls nearby. In real situations there may exist ceiling, side wall and floor, all of which can affect the flow field and suction performance by way of the no-slip condition on the walls. 3D CFD simulation was performed in order to see the effect of the floor on the capture performance of the VV. The presence of floor reduced suction flow velocity, and increased the critical rotational speed which is the rotational speed required for stable vortex formation. Flow velocity profile along the axis could be well approximated by a universal functional form when the distance from the exhaust inlet is non-dimensionalized by the distance to the floor. Capture depth, define by the distance from the exhaust inlet to a point of velocity decreased to 10% of that at the inlet, is reduced by about 10% when the floor distance is 6 times the exhaust hood diameter.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1994년도 추계학술대회 논문집
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• pp.266-272
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• 1994

An essential ingredient in precision machining is a positioning system that responds quickly and precisely to very small input signal. In this paper, two different positioning systems were presented fot the precision positioning control. The one is a friction drive system, the other is a ballscrew system. The friction drive system was composed of an air sliding guide and a friction drive. The ballscrew system was made of a ballscrew and a linear guide. Nonlinear behaviors of the given systems tend to make the system inaccurate. The paper looked at the phenomena that has caused the positioning error. These apparently nonlinear phenomena can be attributed mainly to the presence of the nonlinear friction and slip effect plus the dynamic change from the microdynamic to the macrodynamic and form the macrodynamic to the microdynamic. For the control of the positioning system, the control algorithm based on a neural network is suggested. The FEL(Feedback Error Learning) controller can learn the inverse dynamics of a nonlinear system by using the neural network controller, and stabilize the system by a linear controller. In the experiment, PTP control is implemented withen the maximum error of 0.05 .mu.m ~0.1 .mu. m when i .mu.m step reference input is applied and that of maximum 1 .mu. m when 100 .mu.m step reference input is given. Sinusoidal inputs with the amplitude of 1 .mu.m and 100 .mu. m are used for the tracking control of the positioning system. Experimental results of the proposed algorithm are shown to be superior to those of conventional PD controls.

• 패션비즈니스
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• 제12권1호
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• pp.16-29
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• 2008

The purpose of this essay is to know the expressed form and color and also to examine the inner symbolic meaning of the movie "Sympathy for Lady Vengeance" by producer Chan-Wook Park. In the movie, the main character Geumja has double personality, having both images of a wicked woman and a woman saint, and she showed the clothing of both good and evil. For example, while she was in prison, her prisoner uniform while she was taking care of her inmates, her pajama which is the symbol of innocence when she was atoning and praying, Geumja's appearance wasn't fabulous when she was wearing baker's cloth that symbolize pure inside. But in contrast, Geumja who was released from prison planned and execute vengeance, dress colorful dress and primary color make-ups. Blue color coat with gloomy mood, black leather coat with the image of female warrior, and the slip with intensive image and etc express Geumja's will of revenge. Like this, depend on the psychology of main character Geumja, it's easy to recognize the change of clothing and color, and it's possible to understand the symbolic meaning in it.

• Safety and Health at Work
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• 제7권2호
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• pp.138-142
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• 2016

Background: Household waste collectors (HWCs) are exposed to hazardous conditions. This study investigates the patterns of workplace injuries and work-related illnesses of HWCs. Methods: This study uses cases of workplace injuries and work-related illnesses of HWCs that occurred between 2010 and 2011. We analyzed 325 cases of injuries and 36 cases of illnesses according to the workers' age, length of employment, size of workplace, injured part of body, day and month of injury, type of accident, agency of accident, and collection process. Results: There were significant differences in the effect of workers' length of employment, injured part of body, type of accident, agency of accident, and collection process. Results show that most injuries occur in workers in their 50s and older. This study also shows that 51.4% of injuries occur at businesses with 49 employees or fewer. Injuries to waste collectors happen most often when workers are electrocuted after slipping on the ground. The second most prevalent form of injury is falling, which usually happens when workers hang from the rear of the truck during transportation or otherwise slip and fall from the truck. Work-related illnesses amongst waste collectors are mostly musculoskeletal conditions due to damaging postures. Conclusion: These findings will be instructive in devising policies and guidelines for preventing workplace injuries and work-related illnesses of HWCs.

• 한국의상디자인학회지
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• 제23권2호
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• pp.155-163
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• 2021

This design proposal research is meaningful as Jogakbo can retain the traditional value of the it's design as it becomes a contemporary design proposal. As a specific method of research, history was been investigated to find meaning and formative characteristics defined through prior research under the theme of Jogakbo. Ideas, such as silhouettes, details for design, and the making domestic and foreign designer examples were obtained. The fabric used for the works were recycled from past leather works. All materials are sheep skin. There were various processed surfaces used to avoid monotony. Jogakbo's cotton composition focused on free and radial patterns. The pattern was manufactured using a flat and 3D combination, and the selection of items was mainly made with a simple and light silhouette, so that Jogakbo's details, such as dresses, slip dress, and vests could stand out. Color is an important factor in Jogakbo. However, traditions which are relics of the times, do not need to be preserved in their original form. If changes are inherited with reasonable grounds and directions in line with the changing times, the significance and values are retained are sufficient. It is hoped that these design development studies will continue in the future so that our precious cultural heritage can continue to change and develop positively.

• Steel and Composite Structures
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• 제38권6호
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• pp.739-749
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• 2021

This paper introduces an improved design equation to evaluate the resisting capacity of circular reinforced concrete (RC) columns partially strengthened with outer steel tube. When RC column members are required to be strengthened according to the change in the loadings considered and/or the deterioration progress in columns, wrapping up RC column with steel circular tube, which takes the form of concrete filled steel tube (CFST), has been popularly considered because of its structural advantage induced from the confinement effect. However, the relatively high construction cost of steel tube is restricting its use to the required region, while deriving the shape of a partial CFST column. To evaluate the resisting capacity of a partial CFST column, numerical analyses need to be performed, and a numerical model proposed in the previous study for the numerical analysis of full CFST columns is used to conduct parametric studies for the introduction of a design equation. The bond-slip effect developed along the interface between the in-filled concrete and the exterior steel tube is taken into consideration and the validity of the numerical model has been established through correlation studies between experimental data and numerical results for partial CFST circular columns. Moreover, parametric studies make it possible to introduce a design equation for determining the optimum length of outer steel tube which produces partial CFST circular columns.

• 자원환경지질
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• 제52권3호
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• pp.251-258
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• 2019

양산단층 남부 지역을 대상으로 한 정밀 지질조사 수행 중에 울산광역시 두서면 미호리 신우목장 절개사면에서 미고결퇴적층을 자르고 있는 단층이 확인되었으며, 이는 양산단층 남부 인근 이서 지역에서 최초로 발견된 제4기 단층노두이다. 본 연구에서는 신우지점 주변의 지형, 수계 및 선형구조 분석 결과를 바탕으로 신우지점에서 관찰되는 단층의 기하학적 특성 및 미고결퇴적층의 특징 등의 정보를 제공하고자 한다. 단층이 발달하고 있는 지형은 침식 산록 완사면으로 보이나 저위면의 두꺼운 퇴적층과 중위면의 부채꼴(Fan) 양상은 충적선상지 지형 특징을 보인다. 수계는 3차 수계까지 발달하여 1차 수계와 2차 수계가 서로 직각으로 만나면서 방사상 형태를 보인다. 또한 하천의 휘어짐과 지형면의 단차를 통해 본 지점을 통과하는 북동-남서 방향의 선형구조들이 인지되었다. 신우지점의 단층은 $N30-35^{\circ}E/79-82^{\circ}SE$ 의 자세를 보이며, 약 5.8 m 의 겉보기 수직 변위가 관찰되는 역단층의 기하를 보인다. 단층면에서 확인된 단층조선과 단층 하반의 최상부 미고결퇴적층 내 역들의 방향성도 전형적인 역단층 운동감각을 지시한다. 하지만 단층의 하반 내 일부 단층대를 따라 불연속적인 퇴적물이 관찰되며, 이는 주향이동운동에 의한 열극구조를 상위의 미고결퇴적물이 채운 것으로 판단된다. 현재 절대연령 측정 및 추가적인 조사가 수행 중이며, 추후 이러한 다학제적 조사결과가 도출된다면 본 신우지점 제4기 단층노두에 대한 정확한 단층의 형성 및 발달사가 규명될 수 있을 것으로 사료된다.

• 대한영양사협회학술지
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• 제22권2호
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• pp.118-130
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• 2016

The objectives of this study were to analyze the operational characteristics and to explore the substantiality plan of inpatient diets for foreigners in hospitals. Questionnaires were mail-delivered to 128 hospitals, and a total of 62 questionnaires were usable with a response rate of 48.4 percent. Statistical data analysis was completed using SPSS Win 11.0 for descriptive analysis, independent t-test, and ${\chi}^2$ test. Results can be summarized as follows. The average number of inpatient meals for foreigners in the last 6 months were 405 and 53 for general therapeutic diets and special therapeutic diets, respectively. The rates of hospitals with an exclusive department and exclusive staff for foreign inpatients were 48.4% and 53.2%, respectively. Major nationalities of foreign inpatients were China (37.5%) and Russia (31.3%), and their major medical departments were internal medicine (43.9%) and surgery (39.0%). The number of hospitals that provided inpatient diet only for foreigners was 42 (72.4%) and influencing factors were number of permitted beds (P<0.05), an exclusive department (P<0.001), and exclusive staff (P<0.01). The main type of menu was USA European style (61.1%), and the price of inpatient meals for foreigners was mostly \10,000~\25,000 (62.0%). As 75.9% of hospitals did not possess dietary slip manuals for foreigners, the case of preparing inpatient meals for foreigners in the form of a general therapeutic diet partially-modified according to disease was the majority (55.4%). Dietitians felt the need for nutrition management guidelines and dietary slip manuals (47.3%) as a substantiality plan of inpatient diets for foreigners. There is a need for exclusive foodservice standards for foreign inpatients in the changing medical environment.