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원형 Cavity를 이용한 펄스형 Nb:YAG 레이저의 출력특성 및 병렬메쉬 회로의 최적화
홍정환,송금영,양동민,김휘영,김희제 부산대학교 생산기술연구소 2001 生産技術硏究所論文集 Vol.60 No.-
본 연구에서는 기존의 타원형 cavity가 아닌 원형 cavity를 설계 및 제작하여 그 동작특성에 관하여 연구하였다. 그 결과 타원형 cavity 보다 다소 적은 레이저 출력 효율 2.1%를 얻었다. 원형 cavity는 타원형 cavity 보다 컴팩트하며 제작하기가 용이하고, 제작 단가가 저렴하다는 장점이 있다. 입력에너지, 입력전압 및 펄스 폭을 동일하게 했을 경우 주회로 병렬 메쉬회로수를 최적화하고자 한다. PFN 회로를 1단에서 8단까지 PSPICE로 모의시험한 전류파형과 실제 실험한 전류파형이 거의 일치하였다. 그 결과 500㎲이상의 펄스 폭에서 6단 메쉬가 최적의 병렬 메쉬라는 결론을 얻었다. In this study, we have deigned and manufactured not only a present elliptic cavity but also a circular cavity, and experimented the operational characteristics. As a result, we obtained the maximum efficiency of 2.1% that was not less than that of an elliptic cavity. A circular cavity is much more compact and is easier to be manufactured than an elliptic cavity. And it can be made at a low cost. When the input energy, input voltage, and pulse width were in the same condition, we tried to decide the optimization of the mesh number of a parallel-mesh circuit which was connected with main power supply. The PSPICE simulation waveform of PFP(Pulse Forming network) circuit ranging from 1-mesh to 8-mesh nearly corresponded with the real current waveform obtained through a practical experiment. From these experimental results, we obtained the result that 6-mesh was the optimal parallel-mesh circuit in case that the pulse width was more than 500㎲.
( Dong-min Kum ),( Won-seob Shin ) 물리치료재활과학회 2017 Physical therapy rehabilitation science Vol.6 No.3
Objective: The purpose of this study was to investigate the effects of backward treadmill gait training between underwater and ground environments on strength, proprioception, and walking ability in persons with stroke. Design: Randomized control trial. Methods: Twenty eight subjects participated in the study in which they were randomly assigned to either the underwater backward treadmill training (UBTT) group (n=13) or the BTT group (n=15). In both groups, forward gait training was performed for 20 minutes on the ground treadmill. The UBTT group performed backward gait on an underwater treadmill for 20 minutes while the BTT group performed backward gait on a ground treadmill for 20 minutes. The gait training in each group was performed twice a week for a total of six weeks. Muscle strength, proprioception, and gait ability was assessed using a digital power meter, joint angle recurrence method using the smartphone protractor application, the Figure-of-Eight walk test (F8W) and the functional gait assessment (FGA) respectively. Results: Both groups showed significant improvement in strength, F8W and FGA scores after training (p<0.05). However, there was no statistically significant difference between the two groups. Both groups showed significant improvement in proprioception after training (p<0.05). In the comparison between the two groups, there was a greater significant change in the UBTT group for joint proprioception (p<0.05). Conclusions: In this study, it was found that both backward treadmill gait training programs were effective on strength, proprioception, and gait ability, and that underwater training was particularly effective on proprioception compared to ground training.
Kum, Dong-Min,Shin, Won-Seob korean Academy of Physical Therapy Rehabilitation 2017 Physical therapy rehabilitation science Vol.6 No.3
Objective: The purpose of this study was to investigate the effects of backward treadmill gait training between underwater and ground environments on strength, proprioception, and walking ability in persons with stroke. Design: Randomized control trial. Methods: Twenty eight subjects participated in the study in which they were randomly assigned to either the underwater backward treadmill training (UBTT) group (n=13) or the BTT group (n=15). In both groups, forward gait training was performed for 20 minutes on the ground treadmill. The UBTT group performed backward gait on an underwater treadmill for 20 minutes while the BTT group performed backward gait on a ground treadmill for 20 minutes. The gait training in each group was performed twice a week for a total of six weeks. Muscle strength, proprioception, and gait ability was assessed using a digital power meter, joint angle recurrence method using the smartphone protractor application, the Figure-of-Eight walk test (F8W) and the functional gait assessment (FGA) respectively. Results: Both groups showed significant improvement in strength, F8W and FGA scores after training (p<0.05). However, there was no statistically significant difference between the two groups. Both groups showed significant improvement in proprioception after training (p<0.05). In the comparison between the two groups, there was a greater significant change in the UBTT group for joint proprioception (p<0.05). Conclusions: In this study, it was found that both backward treadmill gait training programs were effective on strength, proprioception, and gait ability, and that underwater training was particularly effective on proprioception compared to ground training.
시강우량을 이용한 필지별 유출-유사 평가 시스템 및 BMPs 평가 모듈 개발 및 적용성 평가
금동혁 ( Dong Hyuk Kum ),류지철 ( Ji Chul Ryu ),최재완 ( Jae Wan Choi ),신민환 ( Min Hwan Shin ),신동석 ( Dong Suk Shin ),천세억 ( Se Uk Cheon ),최중대 ( Joong Dae Choi ),임경재 ( Kyoung Jae Kim ) 한국물환경학회 ( 구 한국수질보전학회 ) 2012 한국물환경학회지 Vol.28 No.3
Soil erosion has been emphasized as serious environmental problem affecting water quality in the receiving waterbodies. Recently, Best Management Practices (BMPs) have been applied at a field to reduce soil erosion and its effectiveness in soil erosion reduction has been monitored with various methods. Although monitoring at fields/watershed outlets would be accurate way for these ends, it is not possible at some fields/watersheds due to various limitations in direct monitoring. Thus modeling has been suggested as an alternative way to evaluate effects of the BMPs. Most models, which have been used in evaluating hydrology and water quality at a watershed, could not reflect rainfall intensity in runoff generation and soil erosion processes. In addition, source codes of these models are not always public for modification/enhancement. Thus, runoff- sediment evaluation system using hourly rainfall data and vegetated filter strip (VFS) evaluation module at field level were developed using open source MapWindow GIS component in this study. This evaluation system was applied to Bangdongri, Chuncheonsi to evaluate its prediction ability and VFS module in this study. The NSE and R2 values for runoff estimation were 0.86 and 0.91, respectively, and measured and simulated sediment yield were 15.2 kg and 16.5 kg indicating this system, developed in this study, can be used to simulate runoff and sediment yield with acceptable accuracies. Nine VFS scenarios were evaluated for effectiveness of soil erosion reduction. Reduction efficiency of the VFS was high when sediment inflow was small. As shown in this study, this evaluation system can be used for evaluation BMPs with local rainfall intensity and variations considered with ease-of-use GIS interface.
( Dong Min Cha ),( Kyeong Hwan Kim ),( Hyuk Jin Choi ),( Mee Kum Kim ),( Won Ryang Wee ) 대한안과학회 2012 Korean Journal of Ophthalmology Vol.26 No.6
Purpose: To compare the effect of using fibrin glue or 10-0 nylon sutures on the clinical outcome of patients undergoing pterygium excision and conjunctival autografting. Methods: We retrospectively reviewed the medical records of 52 eyes from 46 patients who underwent pterygium excision and conjunctival autografting and were followed up for more than 3 months. The operation duration, postoperative inflammation, complications, and recurrence rates were compared between groups of 20 patients (22 eyes) for whom fibrin glue was used (fibrin glue group) and 26 patients (30 eyes) for whom suturing was performed with 10-0 nylon (suture group) in pterygium excision and conjunctival autografting. Results: The operation duration was 27.71 (5.22) minutes in the fibrin glue group and 43.30 (8.18) minutes in the suture group ( p = 0.000). Seven days after the operation, the fibrin glue group showed milder conjunctival inflammation than the suture group ( p = 0.000). Postoperative complications and corneal recurrence rates were not statistically different between the two groups. Conclusions: The use of fibrin glue in pterygium excision with conjunctival autografting is likely to be a more effective, safer procedure than suturing.
토양유실 저감을 위한 지표피복 저감효과 변수 결정 및 SWAT 모형 유역단위 효과 분석
금동혁 ( Dong Hyuk Kum ),장춘화 ( Chun Hwa Jang ),신민환 ( Min Hwan Shin ),최중대 ( Joong Dae Choi ),김범철 ( Bom Chul Kim ),정교철 ( Gyo Cheol Jeong ),원철희 ( Chul Hee Won ),임경재 ( Kyoung Jae Lim ) 한국물환경학회 2012 한국물환경학회지 Vol.28 No.6
The purpose of this study was to determine parameters of surface cover materials and evaluation the effects on runoff and sediment reductions with rice straw mat with PAM at watershed scale using the SWAT model. In this study, 1) regression equation of CN for rice straw mat +PAM using SCS curve number method was developed, 2) the USLE P factor, being able to reflect simulation of rice straw mat+PAM in the agricultural field, was estimated for various slope scenarios with VFSMOD-w. Then regression equation for CN and USLE P factor were used as input data in the SWAT model. Assuming rice straw mat+PAM is applied to radish and potato fields, occupying 24% of agricultural fields at the study watershed. Result of direct runoff without rice straw mat+PAM was 65,964,368 m3, with rice straw mat+PAM, direct runoff was 65,637,336 m3 327,031.8 m3 reductions compared without it. Also, result of sediment without rice straw mat+PAM was 163,531 ton, with rice straw mat+PAM, sediment was 84,779 ton, 78,752 ton reduction compared without it. This analysis showed that about 48% sediment reductions would be expected with rice straw mat+PAM. As shown in this study, rice straw mat+PAM would be used as an efficient site-specific BMPs to reduce runoff and sediment discharge from field.