• The Journal of Korean Physical Therapy
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• 제10권1호
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• pp.127-138
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• 1998

This study was carried out tn invstigate and compare biomechanical characteristics during free speed gait in hemiplegic patients after stroke who took therapeutic exercise by analyzing kinematic and kinetic data in the sagital plane and electromyographic data. Six patients($41\~69$ years old) and age-matched six volunteers in good health(51-61 years old) wire studied. The patients were sorted into two groups, depending on their self-speed of walking : fast speed group(3 patients) and slow speed group(3 patients). The results were as fellows. : 1. In spatio-temparal parameters, affected and unaffected side of fast group showed symetry but blew group showed asymetry of single limb support, opposite foot contact and stance phase (p<0.05). Compared with normal group, patient group showed slower velocity, shoter stride length and longer double limb support (p<0.05). 2. In the pelvic anterior tilt, patient group showed lower valued than normal group. It. In the ground reaction force-vertical force, fast group showed similar double peak gragh compared with normal group, butvslow group showed lower values without double peak (p<0.05).

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 추계학술대회 논문집
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• pp.247-252
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• 2001

Recently the steel parts used at automobiles are required to be used under high stress more than ever before in need of the weight down. To achieve this requirement of a high strength steel, it must be necessary to decrease inclusion content and surface defect as like decarburization, surface roughness etc.. In this study, the surface conditions are measured to know the influence on fatigue properties by two cases of shot peening of two-stage shot peening and single-stage shot peening. And for this study, two kinds of spring steel (SUP7, 50CrV4) are used. This study shows the outstanding improvement of fatigue properties at the case of two-stage shot peening in the rotary bending fatigue test and this is assumed to be from on low stress condition, the 1st stage shot peening is not affected by nonmetallic inclusion under metal. it is possible that the 2nd stage shot peening increases the fatigue life and the high stress but that is affected by nonmetallic inclusion under metal. so far beeasily 50CrV4 have made high stress. But, results also show fatigue failures originated at inclusion near surface, and this inclusion type is turned out to be a alumina of high hardness.

• 한국전자파학회논문지
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• 제14권1호
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• pp.54-61
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• 2003

본 논문은 중 전압 전력선(22.9 kV)에서 방사되는 전자파 특성결과를 보여주고 있다. 측정은 주파수범위 9 kHz∼30 MHz의 통신 신호를 중 전압 전력선로에 인가하였을 때 측정을 하였다. 측정결과 단일 반송신호보다 다중 반송신호에서 방사되는 전자파의 특성이 우수하며 다중반송신호의 세기가 20 dBm일 때 전력선 통신 신호는 1.8 km까지 전송 가능함을 알 수가 있었다. 전기장의 세기는 10 m 법으로 측정하였을 때 30 MHz에서 40 dBuV/m이하의 값을 볼 수가 있었다.

• 한국가시화정보학회지
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• 제1권2호
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• pp.29-37
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• 2003

During the past five decades or so, the characteristics of turbulent swirling flow have been studied extensively because of its great technological and scientific importance. It is well known that the swirling flow improves heat transfer in duct flow. The reason for this is due to the effect of streamline curvature associated with the tangential velocity component. Although many studies have been carried out to investigate the characteristics of the swirling flow in a circular tube. The experimental methods for measuring the velocity components are by hot-wire or LDV (Laser-Doppler-Velocimetry) measuring single point velocity so far. The present study was aimed to analyse the flow characteristics of swirling flow such as time-mean velocity vector, local velocity turbulence intensity and turbulence kinetic energy by using PIV(Particle-Image Velocimetry). The experiment was carried out for four Reynold numbers $1.0\times10^{4}$, $1.5\times10^{4}$, $2.0\times10^{4}$ and $2.5\times10^{4}$ of the measuring area.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.357-360
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• 2009

The present study focused on the segmented cell which has the similar performance to unaltered (not segmented) cell in real operating condition. Many literatures have been made the segmented cell to observe the behavior of local current density distribution in the single cell. However, it has been lack of scheme to segment the cell in that the detailed interpretation of segmenting in analytic point of view was insufficient. Hence, the basic idea of segmenting was introduced to determine the component to be segmented in anode side of unit cell. The electrical contact/bulk resistance was measured by using four wire/probe method through each part of cell components including MEA, GDL, Bipolar Plate and Current Collector. Electron transport mechanism was predicted by comparing resistance values which were obtained from the experiment. As a result, this offered a great benefit to segment the cell efficiently. With this method further experiments would be conducted in research areas which require current density distribution at the same operating condition as unaltered cell.

• 한국압력기기공학회 논문집
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• 제14권1호
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• pp.58-65
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• 2018

The purpose of this study is to develop a Half Nozzle Repair(HNR) process to prevent the leakage from welds on small bore piping in Reactor Coolant System. The Codes & Standards of tempered bead and design requirements of J-Groove welds are reviewed. Automatic machine GTAW welding and machining equipments are developed to perform HNR process. Single pass welding and overlay welding equipments are conducted in order to obtain the optimal temper bead welding process parameters with Alloy 52M filler wire. Coarse grain heat affected zone(CGHAZ) is formed by rapid cooling rate in heat affected zone after welding. Accordingly, a proper temper bead technique is required to reduce CGHAZ in 1-Layer of welds by 2- and 3-Layers. Mock-up tests show that the developed HNR process is possible to meet ASME Code & Standard requirements without any defect.

• 방사성폐기물학회지
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• 제18권2호
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• pp.143-155
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• 2020

A reference electrode is important for controlling electrochemical reactions. Evaluating properties such as the reduction potential of the elements is necessary to optimize the electrochemical processes in pyroprocessing, especially in a multicomponent environment. In molten chloride systems, which are widely used in pyroprocessing, a reference electrode is made by enclosing the silver wire and molten salt solution containing silver chloride into the membranes. However, owing to the high temperature of the molten salt, the choice of the membrane for the reference electrode is limited. In this study, three types of electroceramic, mullite, Pyrex, and quartz, were compared as reference electrode membranes. They are widely used in molten salt electrochemical processes. The potential measurements between the two reference electrode systems showed that the mullite membrane has potential deviations of approximately 50 mV or less at temperatures higher than 650℃, Pyrex at temperatures lower than 500℃, and quartz at temperatures higher than 800℃. Cyclic voltammograms with different membranes showed a significant potential shift when different membranes were utilized. This research demonstrated the uncertainties of potential measurement by a single membrane and the potential shift that occurs because of the use of different membranes.

• 한국수산과학회지
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• 제14권1호
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• pp.37-42
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• 1981

무지개송어의 자어기에 Ichthyophonus sp.인 곰팡이가 감염되어 있는 것을 발견하고 그 후 계속 사육된 어군을 6개월마다 채집하여 병리조직학적으로 관찰하였다. 1. 무지개송어의 치어에는 Ichthyophonus sp.가 전신적으로 감염되어 있었으며, 2년생인 어류에는 Ichthyophonus sp.를 둘러싼 육아종이 많이 발생되고 있었다. 2. 각 조직내에 보이는 Ichthyophonus sp.는 다핵구상체가 가장 많았으며, 때로는 발아중인것과 계장체도 나타났다. 3. Ichthyophonus sp.의 cyst 주변에는 대단핵세포가 모인 번식성 염증를 볼 수 있었다.

• Computers and Concrete
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• 제12권2호
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• pp.187-209
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• 2013

This paper presents a study on the prediction of transfer length of 13 mm seven-wire prestressing steel strand in pretensioned prestressed concrete members with rectangular cross-section including several material properties and design and manufacture parameters. To this end, a carefully selected database consisting of 207 different cases coming from 18 different sources spanning a variety of practical transfer length prediction situations was compiled. 16 single input features and 5 combined input features are analyzed. A widely used feedforward neural regression model was considered as a representative of several machine learning methods that have already been used in the engineering field. Classical multiple linear regression was also considered in order to comparatively assess performance and robustness in this context. The results show that the implemented model has good prediction and generalization capacity when it is used on large input data sets of practical interest from the engineering point of view. In particular, a neural model is proposed -using only 4 hidden units and 10 input variables-which significantly reduces in 30% and 60% the errors in transfer length prediction when using standard linear regression or fixed formulas, respectively.

• 한국항공우주학회지
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• 제38권4호
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• pp.389-394
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• 2010

본 연구에서는 과학기술위성 2호와 비교 했을 때 고속의 데이터를 처리하고 대용량의 메모리를 관리해야하는 요구사항을 만족하기 위한 과학기술위성 3호 대용량 메모리 유닛의 설계 내용에 대해서 나타내었다. 이러한 요구사항을 만족하기 위해서, 두 개의 탑재체에서 각각 최대 100Mbps로 수신되는 데이터와 32Gb의 대용량 메모리를 처리하고 관리하는 역할을 FPGA가 직접 담당 하도록 설계하였다. 사용된 FPGA는 동작 속도가 빠르고 게이트 수가 많은 SRAM 기반의 Xilinx FPGA로써 우주 환경에서의 SEU를 극복하기 위해서 TMR 기법과 스크러빙 기법을 적용하고자 한다.