• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.400-402
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• 1994

The voltage drop in distribution path of battery-reserved DC power system can affect the total of battery, cable and electricity costs. To determine an optimum voltage drop in distribution path for minimizing the total cost, battery, cable and electricity costs are represented as a function of the voltage drop, respectively, and are summed up to the total cost. An optimum voltage drop is selected as the value giving the minimum total cost. In this paper, a design technique of optimum voltage drop in distribution path of DC power system is proposed to minimize the total of battery, cable and electricity costs. The design procedure is described and design curve for selecting optimum voltage drop is also presented as a function of distribution distance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.118-120
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• 2002

Voltage drop of low voltage distribution line is closely related with proper voltage regulation. It depends on the voltage drop of pole transformer, low voltage distribution line, and low voltage customer entrance line. Using above voltage drop factors, we proposes an estimation method of voltage drop in low voltage distribution line. Proposed method has been applied to a 22.9kV practical distribution system.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권1호
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• pp.27-38
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• 2014

Flow mixing and pressure drop characteristics for marine selective catalytic reduction applications were investigated numerically to develop an efficient static mixer. Two different mixers, line- and swirl-type, were considered. The effect of vane angles on the relative intensity, uniformity index, and pressure drop was investigated in a swirl-type mixer; these parameters are dramatically affected by the mixer geometry. The presence of a mixer, regardless of the mixer type, led to an improvement of approximately 20% in the mixing performance behind the mixer in comparison to not having a mixer. In particular, there was a tradeoff relationship between the uniformity and the pressure drop. Considering the mixing performance and the pressure drop, the swirl-type mixer was more suitable than the line-type mixer in this study.

• Nuclear Engineering and Technology
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• 제53권10호
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• pp.3229-3235
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• 2021

The key process used in nuclear industries for the management of radiotoxicity associated with spent fuel in a closed fuel cycle is solvent extraction. An understanding of hydrodynamics and mass transfer is of primary importance for the design of mass transfer equipment used in solvent extraction processes. Understanding the interfacial phenomenon and the associated hydrodynamics of the liquid drops is essential for model-based design of mass transfer devices. In this work, the phenomenon of drop formation at the tip of a nozzle submerged in quiescent immiscible liquid phase is revisited. Previously reported force balance based models and empirical correlations are analyzed. Experiments are carried out to capture the process of drop formation using high-speed imaging technique. The images are digitally processed to measure the average drop diameter. A correlation based on the force balance model is proposed to estimate drop diameter and jet length. The average drop diameter obtained from the proposed model is in good agreement with experimental data with an average error of 6.3%. The developed model is applicable in both the necking as well as jetting regime and is validated for liquid-liquid systems having low, moderate and high interfacial tension.

• 국제물리치료학회지
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• 제10권4호
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• pp.1903-1906
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• 2019

Background: Foot drop is a common symptom after stroke and causes walking disorders. Therefore, its proper treatment is important for improving the walking ability of patients with foot drop. Objective: This study aimed to investigate the effects of electrostimulation during walking on the walking ability of patients with foot drop after stroke. Design: Quasi-experial study. Methods: The study enrolled 18 patients with foot drop after stroke. All subjects were assigned to the experimental or control group. The experimental group underwent electric stimulation during walking, while the control group used ankle foot orthoses. Both groups received treatment 20 minutes a day 5 times a week for 4 weeks. Outcome measures were assessed for walking and balance ability using the 10-m walking test (10MWT), 6-min walking test (6MWT), and Timed Up and Go test (TUG) Results: After the intervention, both groups showed significant improvements in 6MWT and TUG results. However, the experimental group showed significantly better improvement on all tests than the control group. Conclusion: The foot drop stimulator effectively improved the walking and balance ability of patients with foot drop after stroke.

• Journal of Korean Neurosurgical Society
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• 제53권5호
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• pp.269-273
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• 2013

Objective : Posture induced common peroneal nerve (CPN) palsy is usually produced during the prolonged squatting or habitual leg crossing while seated, especially in Asian culture and is manifested by the onset of foot drop. Because of its similarity to discogenic foot drop, patients may be diagnosed with a lumbar disc disorder, and in some patients, surgeons may perform unnecessary examinations and even spine surgery. The purpose of our study is to establish the clinical characteristics and diagnostic assessment of posture induced CPN palsy. Methods : From June 2008 to June 2012, a retrospective study was performed on 26 patients diagnosed with peroneal nerve palsy in neurophysiologic study among patients experiencing foot drop after maintaining a certain posture for a long time. Results : The inducing postures were squatting (14 patients), sitting cross-legged (6 patients), lying down (4 patients), walking and driving. The mean prolonged neural injury time was 124.2 minutes. The most common clinical presentation was foot drop and the most affected sensory area was dorsum of the foot with tingling sensation (14 patients), numbness (8 patients), and burning sensation (4 patients). The clinical improvement began after a mean 6 weeks, which is not related to neural injury times. Electrophysiology evaluation was performed after 2 weeks later and showed delayed CPN nerve conduction study (NCS) in 24 patients and deep peroneal nerve in 2 patients. Conclusion : We suggest that an awareness of these clinical characteristics and diagnostic assessment methods may help clinicians make a diagnosis of posture induced CPN palsy and preclude unnecessary studies or inappropriate treatment in foot drop patients.

• 한국콘텐츠학회논문지
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• 제18권12호
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• pp.197-207
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• 2018

본 연구는 일시청소년쉼터 이용 가출청소년의 사회적 지지, 진로태도성숙이 자립준비에 미치는 영향을 분석한 연구이다. 본 연구 결과 사회적 지지 중 친구 지지가 실무자 지지보다 자립준비에 좀 더 많은 영향을 미치고 있었으며 진로태도성숙은 자립준비의 하위변인 모두에 매우 큰 영향을 미치고 있었다. 곧 가출청소년의 진로태도성숙 수준은 일반청소년들과 마찬가지로 가출청소년이 자립을 준비하는데 있어 매우 중요한 역할을 담당하고 있었다. 이러한 결과를 토대로 본 연구에서는 가출청소년 자립준비를 위한 지원체계 마련, 일시청소년쉼터 실무자의 역량강화, 자립지원을 위한 일시청소년쉼터 역할 정립에 대한 정책을 제언하였다.

• Journal of Welding and Joining
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• 제20권4호
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• pp.491-497
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• 2002

Dynamic behavior of the molten drop during the peak period in the pulsed-GMAW is simulated in this work using the VOF(volume of the fluid) algerian. The dynamic characteristics of molten drop such as minimum radius, average velocity and displacement of mass center were computed as well as the internal pressure and velocity. The minimum and maximum peak durations for detaching a drop were calculated.. The result of Analysis reveals that peak current and volume of pendant drop are important factors which affecting drop detachment. A simplified model of constant acceleration is proposed to describe the behavior of molten drop during peak current, and its results agree with the experimental results.

• 대한전자공학회논문지SD
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• 제37권8호
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• pp.57-66
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• 2000

비대칭 광섬유 커플러 ADF(add/drop filter)의 필터링 특성을 새로운 연산자 분리 시영역 모델을 이용해서 해석하였다. 연산자 분리 시영역 모델은 방향성 결합기와 브래그 격자를 포함하는 구조의 소자를 전산모사 할 때 미우 유용하다. 먼저 이 모델을 이용하여 대칭구조의 고아섬유 커플러 ADF의 특성을 해석하여 연산자 분리 알고리듬의 정확도를 확인 한 후에, 비대칭 구조 ADF의 특성을 해석하여 필터링 성능의 최적화에 필요한 파라미터 값들을 도출하였다.

• 기본간호학회지
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• 제7권3호
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• pp.391-400
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• 2000

A long-term bed rest results in an inevitable foot drop. Yet preventive device such as a foot board and high-neck tennis shoes, are not widely used. This study was conducted to compare the effects of a pillow-type foot board with that of the band-type device. The band-type device of a resonable price is designed for an effective prevention of foot drop, and the convenience for it use. Among the non-equivalent control group design, foot drop preventive effects, usefulness of the device, as well as its cost effectiveness were examined. The study was carried out for four months from December 1999, and its subject had been patients and nurses of two intensive care units at K medical center in Seoul. According to the study purpose, the data collected were analyzed by $x^2-test$ and t-test. The results are as follow : 1. The ROM of ankle joint is promoted in the experimental group with a band-type device comparing the control group with a pillow type one. Dorsiflexion is particularly increased in the experimental group as compared with the control group, while planterflexion hardly shows any change. 2. The usefulness score of the experimental group nurses using the band-type device (23.97) is higher than that of the control group nurses (18.88). 3. In an aspect of the unit production cost, band-type devices are low-priced compare with pillow-type or other foot board (wooden) or high-neck tennis shoes. In summary, the newly developed band-type device is both useful and preventive for a foot drop. It is also desirable regarding to the production cost and the cost effectiveness. This fact proves that the new anti-foot drop device could be practical both for clinical care and home care. Yet the results were obtained by some subjects, it should be used after a further examination. More effective nursing intervention could be observed throughout general studies, including proper positioning and foot and ankle exercises which are the important variables of the foot drop prevention.