• 유공압시스템학회논문집
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• 제7권1호
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• pp.1-5
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• 2010

This paper presents the experimental results of the radial piston type oil pump with new mechanism for a metal diaphragm hydrogen compressor. Generally, metal diaphragm type hydrogen compressor systems are operated by oil hydraulic power. In this system an oil compensating pump has been demanded to compensate for a leakage oil head chamber. The metal diaphragm type hydrogen compressor consists of an oil compensating pump, commonly used hydraulic piston pump and driven by main crank shaft. The radial piston type oil compensating pump with new rolling contacted piston mechanism is developed and experimented. The developed piston element of the radial piston pump consists of piston, steel ball, return spring, two check valves, eccentric cam and ball racer. In this study, designed 4 type pistons as and orifice hole. Operating characteristics and pressure ripple characteristics are tested under no load to 60bar loaded with every 20bar increasing step and pressure ripple and flow rate are experimentally investigated.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권3호
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• pp.51-64
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• 2015

In the present study, we develop two history matching techniques based on Markov chain Monte Carlo method where radial basis function and Gaussian distribution generated by unconditional geostatistical simulation are employed as the random walk transition kernels. The Bayesian inverse methods for aquifer characterization as the developed models can be effectively applied to the condition even when the targeted information such as hydraulic conductivity is absent and there are transient hydraulic head records due to imposed stress at observation wells. The model which uses unconditional simulation as random walk transition kernel has advantage in that spatial statistics can be directly associated with the predictions. The model using radial basis function network shares the same advantages as the model with unconditional simulation, yet the radial basis function network based the model does not require external geostatistical techniques. Also, by employing radial basis function as transition kernel, multi-scale nested structures can be rigorously addressed. In the validations of the developed models, the overall predictabilities of both models are sound by showing high correlation coefficient between the reference and the predicted. In terms of the model performance, the model with radial basis function network has higher error reduction rate and computational efficiency than with unconditional geostatistical simulation.

• 한국생산제조학회지
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• 제21권4호
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• pp.563-569
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• 2012

In the semiconductor and display device production processes, the handling of sensitive objects needs new carrying technology. Floating carrying motion is a practical alternative solution for non-contact handling of parts and substrates. This paper presents a study of through paths inside the air pressure pick-up head to generate the floating motion. The air motion by conceptual designed paths inside the head gradually develops positive pressure and vacuum between narrow objects. Positive pressure occurs through the head tip before discharging outside of the head. Negative pressure is developed by evacuating the inside head bottom as result of the radial flow connecting the vertical through-holes. The numerical analysis was done to figure out the stable levitation caused by the two acting forces between surfaces. In comparing with the standard case that the levitation gap gets 0.7-0.9 mm, it confirms the suggested head characteristics to show floating capacity in accordance with the head size, number of through-hole, and locations of through-hole in succession of conceptual design for a prototype.

• 정보저장시스템학회논문집
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• 제1권1호
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• pp.29-33
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• 2005

We have developed an optical pickup head for blu-ray disc. We have adopted a liquid crystal panel to compensate thickness difference of cover layer. By disposing DVD/CD compatible objective inside the BD objective in disc radial direction, we could realize a backward compatibility. Furthermore we have inserted a polarization diffractive optical element to reduce the influence from the other layer in BD dual layer.

• Archives of Plastic Surgery
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• 제42권6호
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• pp.769-775
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• 2015

Background The radial forearm flap is a versatile, widely used flap. However, the possibility of donor site complications has led to concern over its use. Some surgeons prefer using other flaps whose donor sites can be closed primarily with less morbidity, including avoiding unpleasant scarring. However, in our experience, donor site stability of the radial forearm flap can be reliably achieved by using well-implemented specific procedures. Here, we present a collection of donor site cases of the radial forearm flap and investigate factors that affect the aesthetic results as the basis for a reference for selecting a radial forearm flap. Methods In this retrospective study, we reviewed 171 cases in which a radial forearm flap was used for free tissue transfer after resecting head and neck cancer. We focused on donor site morbidity rates. Each operation involved a detailed procedure designed to minimize donor site morbidity. Moreover, statistical investigations were conducted for 22 cases to determine factors affecting the scar appearance. Results Only one case developed total skin graft necrosis as a major complication. Scar-related aesthetic results were acceptable, and the body-mass index, body weight, diabetes, and cardiac problems were significant factors related to the appearance of scars. Conclusions Performing the radial forearm flap using a well-implemented detailed technique helps achieve acceptable donor site morbidity results. The aesthetic results were more promising for patients without excess body weight, diabetes, or cardiac problems. Therefore, anxiety about donor site morbidity should not be a reason to avoid selecting the radial forearm flap in suitable patients.

• Clinics in Shoulder and Elbow
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• 제13권2호
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• pp.230-236
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• 2010

목적: Mason 분류 제 2형 및 일부의 3형 요골 두 및 경부 골절에 대하여 제한적 피부절개 및 경피적 도수 정복술 시행 후 기능 및 방사선학적 평가를 통해 임상적 결과를 분석하고자 하였다. 대상 및 방법: 2001년 5월부터 2007년 2월까지 Mason 분류 제 2형 또는 3형의 요골 두 및 경부 골절로 경피적 도수 정복술을 시행받은 13명의 환자 (요골 경부 골절: 9예, 요골 두 및 경부골절: 4예)를 대상으로 하였으며, 환자의 평균 연령은 29세 (11세~59세)였고 남자는 8명, 여자는 5명 이었다. 평균 추시 기간은 1년 6개월 (12개월~2년 9개월)이었다. 요골 두 및 경부의 도수 정복술은 방사선 투시기를 사용하여 골절부위를 확인 후, 골절부위 2~3 cm 원위부에서 1 cm 정도의 피부절개 후 경막 거상기를 이용하여 압박이나 감입 (impacted)형태의 요골 경부골절 및 두부의 부분 함몰된 관절면 골편의 정복을 시행하였다. 정복 후 불안정한 3예에 대해 1예에서 골절부의 경피적 핀고정술을 시행하였고, 2예에서 근위 요척골 간에 경피적 횡 핀고정을 추가 하였으며, 나머지 10예에서는 석고 부목 고정술만 시행하였다. 결과: 방사선학적 평가상 전 예에서 골유합이 관찰되었다. 평균 골유합 기간은 6.2주였다. 요골두의 각형성은 수술 전 평균 33.2도 (30도~42도)에서 수술 후 평균 7.8도 (4도~15도)로 감소하였다. 수술 직후에서 최종 추시시까지의 각변형은 0.7도 (-1도~2도) 였다. 수술 후 주관절의 운동 범위는 굴곡 평균 133.1도 (120도~140도), 신전 평균 7.3도 (0도~25도), 회내전은 80도(72도~90도), 회외전은 84.3도 (78도~90도)였다. Mayo Elbow Performance Index는 평균 96.2점 (80점~100점), American Shoulder and Elbow Surgeons elbow score는 평균 97점 (83점~100점), Disabilities of the Arm, Shoulder and Hand score는 평균 1.2점 (0점~5.8점) 으로 우수한 결과를 얻었다. 합병증으로 각각 한 예에서 일시적인 후골간 요골 신경 마비 증상과 경도의 주관절 외반 변형이 발생하였다. 결론: 경피적 도수 정복술은 관절내 독립적인 감입이 없는 Mason 분류 제 2형 및 일부의 3형 요골 두 골절 및 경부 골절의 치료에 있어서 간단하고 합병증 발생이 적으면서 만족할 만한 결과를 얻을 수 있는 유용한 방법 중의 한가지로 생각된다.

• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 2008년도 제16차 학술대회
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• pp.117-117
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• 2008

• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 2009년도 제17차 학술대회
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• pp.193-193
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• 2009

• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 2002년도 아시아견관절학술대회
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• pp.169-173
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• 2002

• 한국분무공학회지
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• 제28권2호
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• pp.97-104
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• 2023

A sprinkler is a fire suppression system that extinguishes combustible materials in the early stages of a fire, creating a spray. However, spray formation method of the sprinkler can result in an uneven distribution of water spray on the surface of combustible materials. It is necessary to ensure a consistent water flux density regardless of the spray direction and angle. In this study, the water flux distribution was analyzed for the various types of sprinkler head: circular, flush, pendent, and upright types. All sprinkler heads have a K-factor of 80 LPM/(0.1MPa)^0.5. In this study, water collection cubes were used to examine the water flux distribution. The upright type sprinkler head showed a low standard deviation in total sprayed area, indicating a high level of uniformity. The upright type head showed the lowest standard deviation in the radial direction, and also showed the lowest standard deviation in the azimuthal direction. Upright sprinkler head has no obstructing structure along the path of droplets after they are generated. For this reason, upright sprinkler head showed the most uniform water flux distribution on the floor.