• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.128-133
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• 2015

Mushrooms can grow in nature when adequate temperature and humidity are maintained, but such condition can be satisfied for only a short period of time on an annual continuum. Therefore, it can be deemed that a majority of the distributed mushrooms in the current market are produced in an artificially manipulated environment. This study was conducted to resolve the problem of the Oyster mushroom cultivation house's internal temperature and humidity imbalance, where the Oyster mushrooms are cultivated in a multi-layered shelves. The air circulation fans were installed to improve the air uniformity of the Oyster mushroom cultivation house by using multi-layered shelves. During the experiment, the ambient temperature and the ambient relative humidity ranged from $5.2^{\circ}C$ to $20.4^{\circ}C$ and 40% to 100% respectively. Due to the change of the outdoor temperature, the internal temperature of the Oyster mushroom cultivation house also changed, ranging from $13.3^{\circ}C$ to $18.4^{\circ}C$, but the temperature gap between the different internal location of the facility during the conforming recorded time only ranged from $0.2^{\circ}C$ to $1.3^{\circ}C$, being significantly stable. The internal relative humidity, ranging from 82% to 96%, also changed due to the change of the outdoor temperature. Nevertheless, the relative humidity gap between the different internal location during the conforming recorded time only ranged from 2% to 7%. Furthermore, the research staff were able to maintain the concentration of $CO_2$ from 575ppm to 731ppm(below 1,000ppm was the goal) indicating the possibility of an even management of the internal environment by installing the air circulation fan.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.05a
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• pp.361-365
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• 2002

최근 고감성 PET 사를 이용하여 생산한 PET 직물은 고감성 의류용 직물로서 많이 사용되고 있다. 이러한 고감성 의류용 PET 직물은 다양한 공정을 거치면서 장력이나 열 등의 영향을 받으므로서 사의 물성의 변화를 초래하여 감성 의류용도의 PET 직물에 많은 결점을 유발 시키므로서 직물 생산 시 공정조건 설정 등의 어려움에 직면하고 있다. 이러한 고감성 의류에 치명적인 문제를 유발하는 문제점에 관한 감성사 제조 시의 공정조건 변화와 관련된 연구 논문은 많이 발표가 되지 못하고 있다. 따라서 본 연구에서는 국내 7개 원사 Maker의 Denier 별 PET 사의 물성을 균일한 길이의 Layer를 설정하여 분석, 조사하고 Layer 별 물성 차이와 습ㆍ건열 열처리 온도에 따른 사의 수축률 등을 비교하므로서 감성 의류용 직물 생산에 필요한 기초 물성 Data를 제공하고 PET 사의 품질향상을 도모하므로서 최종 감성 의류용 직물 소재 개발에 기여할 수 있는 기초자료를 제공하고자 한다.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.239-242
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• 2002

코드사 재봉기는 커튼, 침장류와 같은 제품에 입체구조의 무의를 발현시키기 위하여 30,000 ~50,000d 굵기의 실을 사용하여 직물표면에 입체 무의를 만드는 특수 재봉기이다. 이 재봉기는 작업자가 방향 전환 핸들을 이용하여 무의를 직접 만들어야 하는 수동방식이기 때문에 숙련공의 의존도가 높다. 그래서 숙련공의 의존도를 낮추고 제품의 질, 균일성, 생산성을 향상시키기 위하여 자동화가 절실히 요구되어 왔다[1]. (중략)

• Journal of Mushroom
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• v.15 no.1
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• pp.14-20
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• 2017

The oyster mushroom cultivation house typically has multiple layers of growing shelves that cause the disturbance of air circulation inside the mushroom house. Due to this instability in the internal environment, growth distinction occurs according to the area of the growing shelves. It is known that minimal air circulation around the mushroom cap facilitates the metabolism of mushrooms and improves their quality. For the purpose of this study, a CFD analysis FLUENT R16 has been carried out to improve the internal environment uniformity of the oyster mushroom cultivation house. It is found that installing a section of the working passage towards the ceiling is to maintain the internal environment uniformity of the oyster mushroom cultivation house. When all the environment control equipment - including a unit cooler, an inlet fan, an outlet fan, an air circulation fan, and a humidifier - were operated simultaneously, the reported Root Mean Square (RMS) valuation the growing shelves were as follows: velocity 23.86%, temperature 6.08%, and humidity 2.72%. However, when only a unit cooler and an air circulation fan operated, improved RMS values on the growing shelves were reported as follows: velocity 23.54%, temperature 0.51%, and humidity 0.41%. Therefore, in order to maintain the internal environment uniformity of the mushroom cultivation house, it is essential to reduce the overall operating time of the inlet fan, outlet fan, and humidifier, while simultaneously appropriately manage the internal environment by using a unit cooler and an air circulation fan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.743-750
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• 2017

It is important to ensure a uniform temperature distribution in greenhouses for the mushroom cultivation. The air temperature of the mushroom cultivation greenhouse is made uniform by supplying a constant air temperature with the underground air. The mushroom cultivation array in a greenhouse in seven columns and four rows can make smooth air flows between the rows and prevent air differences between the top and bottom. The buoyancy effect in the entering air of 0.5m/s based on following density difference depending on initial internal temperature needs to be considered. The locations of the Fan Coil Unit (FCU) and fan were defined through flow analysis in a greenhouse to distribute the optimal uniform temperature. In this study, the air conditioning system of a greenhouse with a sandwich heat insulting panel shape which is composed of a FCU and fan was designed by flow analysis. A relatively uniform temperature distribution can be formed because the circulation path of air becomes longer in the different locations of the FCU (inlet) and fan (outlet) through the internal temperature and flow analysis. The cultivation and quality uniformity of the mushrooms could be promoted through these environmental improvements.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.29-33
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• 2011

Background and Purpose: Uniformity is the one of the important quality control features with respect to gamma cameras. To maintain adequate uniformity, we must acquire suitable flood table (=flood map) data because the flood table effects energy, and the type or dose of input radiation. Therefore, in this study we evaluated the difference in uniformity when uniformity does not match between the type of input radiation and the flood table data or collimator type. Subjects and Methods: For input radiation, we prepared 370 MBq of $^{57}Co$, $^{99m}Tc$, and $^{201}Tl$. Using SKYLight (Philips) and Infinia gamma cameras (GE), we acquired nine uniformity data that were corrected by technetium, cobalt flood table and did not corrected image for the three sources. Additionally, we acquired two uniformity images with a collimator that were corrected by intrinsic and extrinsic flood tables. Using this data, we evaluated and compared the uniformity values. Results: In the case of the SKYLight gamma camera, the uniformities of the images that matched between the input radiation and flood table with respect to $^{99m}Tc$ and $^{57}Co$ were better than the unmatched uniformity (3.96% vs. 5.69% ; 4.9% vs. 5.91%). However, because there was no thallium flood table, the uniformities of images at Tl were significantly incorrect (7.49%, 7.03%). The uniformities of the Infinia gamma camera had the same pattern as the SKYLight gamma camera (3.7% vs. 4.5%). Moreover, the uniformity of the $^{99m}Tc$ image acquired with a collimator and corrected by an extrinsic flood table was better than the intrinsic flood table (3.96% vs. 6.28%). Conclusion: Correcting an image by a suitable flood table can help achieve better uniformity for a gamma camera. Therefore, we have to acquire images with suitable uniformity correction, and update the flood table periodically. Whenever we acquire a nuclear medicine image, we always have to check the appropriate flood table according to the acquired condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.2
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• pp.32-42
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• 1998

Lean burn gasoline engine is recognized as a promising way to meet better fuel economy. Lean burn engine is classified into port injection and direct injection(DI), DI is more active technique for improving fuel economy with ultra-lean operation, Nowadays, port injected lean burn engine has been produced by many Japan maker. Also, DI engine is also possible for production owing to improvement in control technique of spray, flow air fuel ratio. DI engine uses either homogeneous stoichiometric mixture or stratified mixture by controlling injection timing to be early or late respectively. HM(homogeneous mixture) is worse than SM(stratified mixture) in view of ultra-lean operation in partical load and Nox reducion by using EGR control. But, HM has advanteges in cold starting and emission reduction during transient operation, This paper describes experimental variables and bench test results of HM GDI engine.

• Journal of Korea Water Resources Association
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• v.54 no.8
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• pp.607-616
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• 2021

The purpose of this study is to simulate the transport of nonuniform sediment considering the hiding-exposure effect numerically. In order to calculate the transport of multi-disperse suspended sediment mixtures, the set of advection-diffusion equations for each particle class is solved. The applicability of the numerical model is examined by comparing the simulation results with experimental data. In this study, we calculate the vertical distribution of total concentration of sediment particles using two approaches: (1) by considering the mixture as represented by a single size; and (2) by combining the concentration of the sediment corresponding to several particle size classes; From the simulation results, it is shown that both approaches calculate reasonable results due to the narrow range of size distribution. Under the condition of nonuniform sediment, the critical shear stress of the sediment particle is influenced by the size-selective entrainment, i.e., hiding-exposure effect. It is shown in this study that the effect of hiding-exposure effect on the erosion rates of fine sand is negligibly small.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.122-125
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• 2003

Easy-care성을 장점으로 하여 천연섬유 대체용으로 점차 차별화가 진행되며 개발된 PET 섬유는 범용적인 섬유특성으로 인해 의류ㆍ비의류용 분야에서 광범위한 소재로 많이 사용되고 있다. 고부가가치의 직물을 생산하기 위해서는 원사의 특성뿐만 아니라 원사 이후의 공정 특히 사가공공정에서의 각공정에 따른 絲의 물성을 파악하는 것이 중요하다. 원사를 가연하는 공정 중 최근 disk spindle과 큰축을 이루고 있는 belt 가연기구는 높은 생산속도와 균일한 가공사를 생산할 수 있어 많이 사용하고 있다. (중략)

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.3
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• pp.319-326
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• 1985

본 연구에서는 준 3차원 유한요소법(quasi 3-D finite element method)을 사 용하여 균일한 변위하중뿐 아니라 적층판의 제작 공정상 필연적인 열하중(thermal loading)의 영향을 동시에 고려하여 층간균열의 발생 및 성장에 대한 특성을 밝히고자 한다. 끝으로 층간 균열이 인장강도에 미치는 영향을 혼합법칙(rule of mixtures)의 개념을 사용하여 평가하고자 한다.