• 한국철도학회논문집
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• 제15권2호
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• pp.141-146
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• 2012

차륜과 레일의 반복적인 구름접촉은 레일 표면결함을 유발하고, 레일 표면결함은 충격하중을 유발하여 소음 진동, 레일파단, 궤도파괴로 이어지고 심할 경우 열차사고(탈선)를 발생할 수 있다. 이러한 레일 표면결함을 제어하기 위한 방법으로 레일연마가 시행되고 있다. 본 연구는 KTX차륜과 UIC레일에서 발생하는 최대 접촉압력을 유한요소해석을 통해 산정하였고, 일반레일 및 열처리레일에 대한 구름접촉피로시험을 수행하여 접촉압력 및 반복횟수에 따른 레일표면 경화층 형성 경향을 분석하였으며, 누적통과톤수에 따라 고속철도 레일에서 발생하는 표면 경화층을 제거하여 건전한 레일표면을 유지하기 위해 0.2mm/2천만톤의 적정 레일연마량을 제안하였다.

• International Journal of Railway
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• 제8권2호
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• pp.50-54
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• 2015

The primary function of the trackbed in a conventional railway track system is to decrease the stresses in the subgrade to be in an acceptable level. A properly designed trackbed layer performs this task adequately. Many design procedures have used assumed and/or are based on critical stiffness values of the layers obtained mostly in the field to calculate an appropriate thickness of the sublayers of the trackbed foundation. However, those stiffness values do not consider strain levels clearly and precisely in the layers. This study proposes a method of computation of stiffness that can handle with strain level in the layers of the trackbed foundation in order to provide properly selected design values of the stiffness of the layers. The shear modulus values are dependent on shear strain level so that the strain levels generated in the subgrade in the trackbed under wheel loading and below plate of Repeated Plate Bearing Test (RPBT) are investigated by finite element analysis program ABAQUS and PLAXIS programs. The strain levels generated in the subgrade from RPBT are compared to those values from RC (Resonant Column) test after some consideration of strain levels and stress consideration. For comparison of shear modulus G obtained from RC test and stiffness moduli $E_{v2}$ obtained from RPBT in the field, many numbers of mid-size RC tests in laboratory and RPBT in field were performed extensively. It was found in this study that there is a big difference in stiffness modulus when the converted $E_{v2}$ values were compared to those values of RC test. It is verified in this study that it is necessary to use precise and increased loading steps to construct nonlinear curves from RPBT in order to get correct $E_{v2}$ values in proper strain levels.

• 반도체디스플레이기술학회지
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• 제20권2호
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• pp.92-97
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• 2021

The importance of processes in cryogenic environments is increasing in a way to address problems such as critical dimension (CD) narrow and bottlenecks in micro-processing. Accordingly, in this paper, we proceed with the design and analysis of Electrostatic Chuck(ESC) and Coolant in cryogenic environments, and present optimal model conditions to provide the temperature distribution analysis of ESC in these environments and the appropriate optimal design. The wafer temperature uniformity was selected as the reference model that the operating conditions of the refrigerant of the liquid nitrogen in the doubled aluminum path were excellent. Design of simulation (DOS) was carried out based on the wheel settings within the selected reference model and the classification of three mass flow and diameter case, respectively. The comparison between factors with p-value less than 0.05 indicates that the optimal design point is when five turns of coolant have a flow rate of 0.3 kg/s and a diameter of 12 mm. ANOVA determines the interactions between the above factor, indicating that mass flow is the most significant among the parameters of interests. In variable selection procedure, Case 2 was also determined to be superior through the two-Sample T-Test of the mean and variance values by dividing five coolant wheels into two (Case 1 : 2+3, Case 2: 3+2). Finally, heat transfer analysis processes such as final difference method (FDM) and heat transfer were also performed to demonstrate the feasibility and adequacy of the analysis process.

• 대한물리치료과학회지
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• 제3권2호
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• pp.1011-1019
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• 1996

The incidence of spinal cord injury increase due to traffic accident, industrial accident and leisure sports. Spinal cord injury damages motor and sensory function below the injury level, also affects autonomic functions associated with voiding and defecation. Sexual dysfunction and psychosocial, vocational maladaptations are also some of the unwanted consequences of injury. The purpose of this study is look for means to prevent and to manage complications in spinal cord injury through investigation and analysis. The subjects of this study in spinal cord injured patients were admitted to the department of physical therapy, Kwangju christian Hospital, Nam Kwang Hospital, Chun Nam university Hospital and Cho Sun university Hospital, from April, 1, 1995 to March, 31, 1996. The results are as follows: 1. The subjects comprised 96 cases of spinal cord injury, ranging from 17 to 85(mean-40.8 yrs) and included 72 males and 24 females. Among these patients, 58 were cervical injury, 20 were thoracic injury and 18 were lumbar injury. 2. As for a major causative of spinal cord injury were traffic accident(59.4%), fall down (27.1 %), and motocycle(4.2%).. 3. The bladder control were taken by indwelling cathetar(41.7%), Crede maneuver(37.5%) and self voiding(16.7%). The bowel control were taken by all aid(61.5%), assitance(32.3%) and self defecation(6.2%). 4. Possible of sexual function were 35 cases (47.9%). 5. The device of transfer used wheel chair(69.8%) and bed(16.7%). 6. The patients with higher cord lesion got more serious pain than lower cord lesion. Also the patients with higher cord lesion got a serious spasticity. 7. The incidence of decubitus ulcer among 96 patients were in case 46(47.9%). The largest group of the pressure sore sites were sacral portion(82.0%), less than 1 month of onset occured a large numbers(50%). Incidence of pressure sore by spasticity occured many patients in case of mild or moderate. Incidence of pressure sore by pain occured many patients in case of severe pain.

• 천문학회보
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• 제35권1호
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• pp.36.2-36.2
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• 2010

The CQUEAN (Camera for QUasars in EArly uNiverse) is an optical CCD camera optimized for observation of high redshift objects. It is going to be attached to the cassegrain focus of 2.1m telescope at McDonald Observatory, USA. We are making a focal reducer for CQUEAN to secure a larger field of view. The focal reducer is composed of four spherical lens, and it reduces the focal length of telescope by one third. We designed the lens configuration, performed tolerance analysis, and estimated the optical performance with ZEMAX. The differences in optical performace with/without filters were also investigated. The result from ZEMAX shows that the system has ample margin of errors for median seeing of 1.2" at McDonald observatory. Even with aberration and alignment tolerance, the performance is better than the original requirement. The lenses are now being made, and the lens barrel and an adapter for assembly of the Andor CCD camera and the filter wheel is now under designing process. We expect that the manufacturing of the focal reducer system as well as its optical test will be finished by April 2010.

• 한국식품영양과학회지
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• 제14권4호
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• pp.353-358
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• 1985

본(本) 연구(硏究)에서는 3종(種)의 잎담배 추출액(抽出液)을 시료(試料)로 하여 동결농축(凍結濃縮)에 관(關)한 기초실험(基礎實驗)으로서 시료용액(試料溶液)의 농도(濃度)와 빙점(氷點)과의 관계(關係), 점도(粘度)와 농도(濃度)와 온도(溫度)와의 관계(關係) 및 빙결정(氷結晶)의 형상(形狀)을 측정(測定)한 결과, 다음과 같은 결론(結論)을 얻었다. 1. 빙점(氷點) $t_m(^{\circ}C)$과 농도(濃度) X(wt%)와의 관계식(關係式)은 아래와 같다. $t_m=-{\frac{18.6X}{170-{\frac{X}{100}}(170+18)}}$ 2. 점도(粘度) ${\mu}(c{\cdot}p)$와 온도(溫度) T(K)와 농도(濃度) X(wt%)의 관계(關係)는 아래식과 같다. $log_{10{\mu}}={\frac{1585}{T}}+2.11{\frac{X}{100-X}}-5.50$ 3. 고농도(高濃度)의 용액(溶液)에서 얇은 수지상형(樹枝狀形)의 빙결정(氷結晶), 저농도용액(低濃度溶液)에서 두꺼운 판상형(板狀形)의 빙결정(氷結晶)이 생성(生成)되었다.

• 대한전기학회논문지:전력기술부문A
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• 제48권2호
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• pp.127-135
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• 1999

Multivarialbe Boiler-Turbine H_\infty Control System Genetic Algorithm Weighting Functions $W_1$(s), $W_2$(s), and design parameter $\gamma$ that are given by Glover-Doyle algorithm, to optimally follow the output of reference model. The first method to do this is that the gains of weighting functions $W_1$(s), $W_2$(s), and design parameter are optimized simultaneously by genetic algorithm with the tournament method that can search more diversely, in the search domain which guarantees the robust stability of system. And the second method is that not only by genetic algorithm with the roulette-wheel method that can search more fast, in that search domain. The boiler-turbine H_\infty control system designed by theabove second method has not only the robust stability to a modeling error but also the the better command tracking preformance than those of the H_\infty control system designed by trial-and-error method and the above first method. Also, this boiler-turbine H_\infty control system has the better performance than that of the LQG/LTR contro lsystem. The effectiveness of this boiler-turbineH_\infty control system is verified by computer simulation.

• 수산해양기술연구
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• 제36권1호
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• pp.25-32
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• 2000

A combination steering system was designed to provide the flexibility in controlling the steering wheel in fishing operations of the inshore and coastal fishing vessels. The designed steering system basically is consisted of three driving units, such as a electrically driven hydraulic pump unit with a solenoid control valve, a DC motor driven hydraulic pump unit and a manually driven hydraulic pump unit, and two controllers to provide remote steering on the deck, respectively. The steering torque was measured and analyzed to investigate the dynamic performance of the developed steering system. The steering system showed excellent linearity between the working pressure of cylinder and the torque of rudder post in case of increasing in rudder angle from $5^{\circ} to 35^{\circ}$ that is, the steering torque increased from $10.4 kgf{\cdot}m$ to $105.3 kgf{\cdot}m$ and then the working pressure of cylinder fluctuated from 6.3 kgf/cm super(2) to 16.4 kgf/cm super(2). The steering time of 3.2 sec in remote hydraulic steering by the on/off solenoid valve control was much faster than 13.2 sec in the manual steering by the helmsman and 11.6 sec in the electric steering by a DC motor, and then it was verified that operation of one unit does not affect other units in combination steering system in any way. Furthermore, the developed steering system can be remotely controlled in multiple stations of the deck during the fishing operation and the automatic pilot steering unit can be used to add hydraulic steering.

• 패션비즈니스
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• 제16권2호
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• pp.44-61
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• 2012

The 21st century directs designomics to achieve wealth by designing old beyond a simple recognition of the importance of culture. One of the representative local cultures of Gyeongnam is Gaya culture. The Gaya period had over 600 years history with rich and excellent iron manufacturing skill and advanced pottery culture. It is the very time to reevaluate the importance of Gaya equivalent to the Three Kingdoms in our ancient history which was has been so far ignored and isolated. In order to develop unique and excellent culture of Gaya as local fashion cutural goods, questionnaire survey on the recognition of Gaya culture and cultural goods purchasing status had been conducted to target visitors of Representative National Museum. Data Analysis Using SPSS 18.0 Win was performed with frequency analysis and t-test. As to the questionnaire survey, important criteria for purchasing in case of buying cultural goods could be found and the residents in Gyeongnam had higher recognition of developing cultural goods by the motif of Gaya relics. 'Mounted vessel in the shape of warrior on horseback(12.4%)' and 'Chariot wheel-shaped Pottery(10.8%)' were selected the most suitable motif, 'Cellphone strap(11.0%)' and 'key holder(10.2%), 'cup (7.2%)'were selected the most suitable item of cutural goods. These will be actively reflected in the development of fashion cultural goods design applying Gaya relics.

• 한국철도학회논문집
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• 제10권5호
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• pp.619-625
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• 2007

본 논문은 인천국제공항철도에서 운행하고 있는 전동차의 동적특성시험을 수행한 결과이다. 인천국제공항철도의 직통형 전동차는 국내 처음으로 120km/h로 주행한 차량으로 탈선계수를 공차와 만차로 구분하여 측정하였다. 탈선계수측정결과 탈선에 대한 안전성을 판단할 때 가장 기본적인 지표로 사용하는 탈선계수는 공차 때가 만차 때보다 높게 나타났으며, 공차와 만차 모두 0.8 미만이었다. 속도에 따른 탈선계수는 80km/h를 전후한 속도 대역으로 운행하는 구간이 선로상태가 좋지 않은 구간으로서 탈선계수도 증가하는 것으로 나타났다. 횡압은 공차 때에는 2.1톤 미만이었으며, 만차 때에는 2.4톤 미만으로 발생하였다. 인천국제공항철도 전동차가 120km/h 주행에서도 안전함을 탈선계수 실측에 의해 확인하였다. 그러나 본 논문에서 적용된 평가방법의 경우 시험방법이 복잡하고, 측정장치 설치의 어려움이 있으며, 비용이 많이 드는 단점이 있었다. 따라서 측정이 간단한 방법으로 영업운전에서도 차량의 안전성을 확인할 수 있는 방안이 연구되어야 할 것이다.