• 해양환경안전학회지
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• 제25권6호
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• pp.802-808
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• 2019

직류전동기는 속도제어가 간단하고, 출력 토크특성이 우수한 장점으로 윈치나 카고 펌프 모터 등으로 선박에서 많이 사용되었으며, 전기추진선박이 도입된 초기에는 선박용 추진전동기로도 적용되었다. 하지만 브러시와 정류기와 같은 기계적 정류장치의 단점으로 인해 최근에는 직류전동기와 전기적인 특성은 매우 유사하지만 기계적인 정류장치를 설치하지 않고 반도체 소자를 이용한 전자적인 정류장치를 사용하는 브러시리스 직류전동기의 사용이 증가하고 있다. 기존의 브러시리스 직류전동기를 구동하기 위한 인버터 시스템은 2상여자방식을 사용하므로 역기전력파형이 사다리꼴모양으로 되며, 이로인해 전류가 흐르는 권선이 바뀌는 상전류 전환 구간에서 고조파와 토크리플이 발생하게 된다. 이러한 고조파와 토크리플을 저감하기 위한 다양한 방안이 연구되어 발표되었으며, 본 연구에서는 전력분석프로그램을 이용하여 브러시리스 직류전동기의 구동회로에 비례적분 속도전류제어기 알고리즘을 구현한 Cascaded H-Bridge 멀티레벨 인버터를 적용하였다. 모델링한 브러시리스 직류전동기의 시뮬레이션을 통해 제안하는 전동기의 구동방식을 적용하는 경우에 기존의 구동방식에 비해 전동기 입력측 전압파형 개선과 고조파 및 토크리플이 현저히 저감되는 결과를 확인할 수 있었다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 추계학술대회 논문집
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• pp.53-56
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• 2000

This paper discusses the horizontally rotaling wind power generator. Quasi static analysis are applied to performance. Translational velocity. which varies on the distance from the rotating wind power generator is effective in speed. In high rotation. the reverse torque reduces the total effective troque. It is recommended to giver efforts to redutorque for the acceptavle performance of the horizontallv rogatting tvpe generator.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2000년도 KIASC Conference 2000 / 2000년도 학술대회 논문집
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• pp.63-66
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• 2000

A rotating cryogenic system was designed similar to the cooling system for the rotor of a superconducting generator. The experimental rotor has an inner vessel which simulates the winding space of an actual superconducting rotor, and a torque tube of comparable design. This paper describes the evaluation of the total heat leak into the inner vessel that leads to the study of the jheat transfer characteristic of the rotating cryogenic system.

• 재활복지공학회논문지
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• 제7권2호
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• pp.101-107
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• 2013

본 연구는 이중 벨트 트레드밀을 이용하여 좌우 독립적 보행 시 횡축 체중부하 감소 유무에 따른 하지 근력불균형 개선효과에 대해 고찰하고자 한다. 피험자들은 하지의 좌우 근력차이가 20% 이상인 자 20명이며 체중부하 감소 유무에 따라 각각 10명씩 그룹으로 나누었다. 실험은 보행운동을 격일로 40분씩 주 3회, 총 4주간 진행되었으며 2주마다 등속성 관절토크 검사를 실시하여 고관절, 슬관절 및 족관절의 최대근력과 평균일률을 평가하였다. 실험 결과, 고관절에서 가장 큰 하지의 좌우 최대근력 불균형 개선효과(12.51%)를 보였으며 슬관절에서는 근반응성 개선효과(10.66%)가 크게 나타났다. 체중부하 감소방법은 하지의 근력불균형 개선효과에 긍정적인 결과를 기대할 수 있다고 사료된다.

• 한국의류학회지
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• 제41권5호
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• pp.950-965
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• 2017

This present study proposed a newly developed test method to evaluate the dexterity and mobility of a firefighter's protective gloves. The first step evaluated the mobility and dexterity of the current type of fire protective gloves and three new types of protective gloves using Don-doff test, ASTM dexterity, Minnesota dexterity, Bennett hand tool test, and ASTM torque test. Three firefighters ($47.3{\pm}5.0yr$ in age, $178.6{\pm}2.9cm$ in height) participated in a series of experiments. The second step was to design and suggest an integrated test method based on the results of the first experiment. As a result of the first experiment, we concluded that 1) the mobility and dexterity tests for firefighting gloves should include both wet and dry tests, 2) The three kinds of dexterity tests could be integrated into one test, and 3) The don-doff test and the torque test should be independent from the newly developed integrated test. In summary, we suggested a simplified test method that combined ASTM dexterity, Minnesota dexterity, and Bennett hand tool test. The integrated system can reduce total time spent on dexterity tests and improve the validity of the test in terms of firefighters' manual work.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.204-209
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• 2004

This paper describes dynamic manipulability analysis of robotic arms moving in viscous fluid. The Manipulability is a functionality of manipulator system in a given configuration and under the limits of joint ability with respect to the tasks required to bt performed. To investigate the manipulability of underwater robotic arms, a modeling and analysis method are presented. The dynamic equation of motion of underwater manipulator is derived from the Lagrange - Euler equation considering with the hydraulic forces caused by added mass, buoyancy and hydraulic drag. The hydraulic drag term in the equation: is established as analytical form using Denavit - Hartenberg (D-H) link coordination of manipulator. Two analytical approaches based on Manipulability Ellipsoid are presented to visualize the manipulability of robotic arm moving in viscous fluid. The one is scaled ellipsoid which transforms the boundary of joint torque to acceleration boundary of end-effector by normalizing the torque in joint space while the other is shifted ellipsoid which depicts total acceleration boundary of end-effector by shifting the ellipsoid in work space. An analysis example of 2-link manipulator with proposed analysis scheme is presented to validate the method.

• 한국전문물리치료학회지
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• 제24권3호
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• pp.21-29
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• 2017

Background: The measurement of the strength of the shoulder muscles is an important element of the overall assessment of patients with various shoulder disorders. However, the clinical utilization of this measurement is dependent on its reproducibility. Objects: To explore the reproducibility of the measurements derived from testing of the isokinetic strength of shoulder muscles in patients with tendinitis of the rotator cuff. Methods: A total of 20 patients with tendinitis of the rotator cuff participated in this study and were assessed twice in 1 week. Isokinetic testing was performed concentrically for shoulder flexors, abductors, and external rotators and eccentrically for the shoulder extensors, adductors, and internal rotators. The relative and absolute reproducibility of the peak torque (PT) and ratios were assessed using intra-class correlation coefficients (ICC), standard error of measurement (SEM), and minimal clinically important difference (MCID), respectively. Results: Overall, high to excellent ICC, clinically acceptable SEM and MCID values were obtained for the PT (ICC: .83-.95, SEM: 1.2%-9%, MCID: 3.4%-25%) and ratios (ICC: .85-.93, SEM: 5.1%-10%, MCID: 14.2%-27.6%). Conclusion: These findings suggest that isokinetic tests may be effectively utilized for the determination of shoulder strength profiles and appropriate position are recommended to perform test without pain in patients with tendinitis of the rotator cuff.

• 한국소음진동공학회논문집
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• 제27권1호
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• pp.14-19
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• 2017

Fuel oil consumption cost varies depending on every ship operation and this roughly amounts to 70 % of shipping companies' total revenue. As such, efforts towards improved fuel economy are being pursued. An annual 1 % reduction in fuel consumption is perceived to result in saving tens million US dollars on the global fleet operation. One approach is the application of power take-off configurations which are seen to increase fuel oil economy and are suitable for power generation. In this study, the dynamic properties of a shaft generator coupled on a 10S90ME main engine of an 18 600 TEU container vessel is presented. The vibratory torque and angular velocity variation was examined through theoretical analysis and actual vibration measurement. The result of the study suggests a review on existing classification rules for generator design and the lowering of vibratory torque and angular velocity variation guideline.

• 대한물리치료과학회지
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• 제2권1호
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• pp.367-373
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• 1995

The purpose of this studied was the comparison with shoulder girdle muscles of isokinetic evaluation in the spinal cord injury group, and adults normal group. Data was collected from 20 cases spinal cord injury from January 10. 1994 to February 10, 1995 in a Chungnam University hospital and adults normal group to 20 cases. The results were as follows; 1. Low speeds peak torque was higher spinal cord group than normal group shoulder girdle muscles of flexor, extensor, external rotator showed statistically significant in spinal cord injury group(p<0.05). Against normal groups shoulder girdle muscles of internal rotator showed statistically significant in normal group(p<0.05). 2. High speeds peak torque was higher spinal cord group than normal group shoulder girdle muscles of flexor, extensor, showed statistically significant in spinal cord injury group(p<0.05). 3. High speeds total work was higher spinal cord group than normal group shoulder girdle muscles of flexor, extensor, external rotator showed statistically significant in spinal cord injury group(p<0.05).(p<0.01). Against normal group shoulder girdle muscles of internal rotator showed statistically significant in normal group(p<0.05).

• Elastomers and Composites
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• 제36권1호
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• pp.37-43
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• 2001

실리카와 카본블랙으로 보강된 SBR 배합물의 가황 특성과 bound rubber 함량 그리고 가황물의 물성에 보강제의 조성비가 미치는 영향을 연구하였다. 고무 배합물의 보강제 총 함량은 80.0 phr 이다. Bound rubber 함량은 실리카 함랑비가 증가할수록 증가하였고 점도 역시 증가하였는데, 특히 실리카 함량이 60.0 phr 이상일 때는 점도의 증가폭이 두드러지게 높아졌다. 가황시간은 실리카 함량이 증가할수록 느려졌고 가황 속도도 느려졌다. 실리카 함량비가 증가할수록 델타 토크가 증가함에도 불구하고 모둘러스는 감소하는 경향을 보였다. $60^{\circ}C$에서의 tan ${\delta}$ 값은 실리카 함량이 증가할수록 감소하였다.