• 산업융합연구
• /
• 제18권4호
• /
• pp.51-59
• /
• 2020

본 연구는 만성 뇌졸중 환자를 대상으로 저항운동이 포함된 거울치료 시 tDCS(transcranial direct current stimulation)의 융합 자극을 통해 마비측 다리의 근력과 보행 능력의 개선을 알아보고자 하였다. 12명의 뇌졸중 환자는 실험군 당 6명씩 무작위로 할당하였다. 실험군I(n=6)은 NDT(neurodevelopmental treatment)와 거울치료 시 sham tDCS의 융합자극군, 실험군II는 NDT와 거울치료 시 tDCS의 융합자극군으로 나누어 각각 30분씩, 주5회, 총4주 동안 실험을 실시하였다. 모든 평가는 중재 전과 중재 4주 후에 실시하였다. 다리근력은 측정한 모든 근육에서 실험군I에 비해 실험군II에서 유의한 차이를 나타냈고(p<.05), 변화량을 통한 군 간 비교에서는 quadriceps(p<.01)와 tibialis anterior(p<.01)에서 유의한 차이를 나타냈다. 보행능력은 실험군I과 실험군II 모두에서 유의한 차이를 나타냈고(p<.05), 변화량을 통한 군 간 비교에서 유의한 차이를 나타냈다(p<.01). 거울치료와 tDCS의 융합자극은 마비측 다리 근력 및 보행능력 향상에 중첩효과를 통한 긍정적인 개선 효과를 주는 것을 알 수 있었다.

• 한국광학회:학술대회논문집
• /
• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
• /
• pp.32-35
• /
• 1989

A 150W industrial Nd:YAG laser was developed. The thermal lensing effect was examined and the radius and position of rear mirror were optimized for higher efficiency. The efficiency of 2.5% was achieved. Also, the performance of laser welding in fine thermocouples and between high-temperature-melting dissimilar metals were investigated.

• 한국광학회지
• /
• 제17권5호
• /
• pp.447-454
• /
• 2006

Brewster 각으로 양면이 가공된 $Cr^{4+}$ : YAG 결정이 장치된 Z자형 공진기의 안정영역에 대하여 열 렌즈 효과를 고려하지 않았을 때와, 고려하였을 때의 경계값의 해석적 해를 구하였다. 또한 수차 변환 행렬들을 사용하여 공진기의 안정성, 빔 허리, 그리고 비점수차 보상에 대한 열 렌즈 효과가 미치는 영향도 알아보았다. 결정이 오목거울 사이의 중간 위치에 놓이고, 오목거울과 반사거울 및 출력거울의 거리가 같을 때에는 공진기의 안정영역에 미치는 열 렌즈 효과의 영향은 적으나, 빔 허리는 반사거울에서 구결면보다 자오면에서의 영향이 더 크므로 열 렌즈 효과가 있을 때의 비점수차 보상은 더 어려워진다. 이러한 결과는 Kerr 렌즈 모드 잠금에서도 열 렌즈 효과가 고려되어야 함을 보인다.

• Journal of the Optical Society of Korea
• /
• 제2권2호
• /
• pp.64-73
• /
• 1998

We have theoretically analyzed and experimentally observed the effects of wavelength dependent birefringence inside a laser cavity on the output characteristics of fiber lasers with a figure eight geometry. The spectral and polarization characteristics of fiber lasers are found to be very susceptible to the resultant birefringence composed of the intrinsically existing wavelength dependent birefringence and the externally induced birefringences inside the fiber. For the variation of twist-induced birefringence inside the nonlinear amplifying loop mirror, the laser output power and center wave-length of continuous wave lasers change periodically, but the polarization characteristics remains nearly unchanged. The changes of the birefringence inside the linear loop has little effect on the spectral characteristics but changes the polarization properties such as the polarization direction.

• 조명전기설비학회논문지
• /
• 제18권2호
• /
• pp.135-141
• /
• 2004

보호계전 시스템의 전류센서로 사용할 목적으로 편광분석형 광섬유 전류센서를 개발하였다. 광섬유의 선형복굴절에 의한 출력의 왜곡을 최소화하기 위하여 단일모드 광섬유를 미터 당 20회 이상 비틀고 그 끝단에 FRM(Faraday rotator mirror)을 부착하여 센서코일을 제작하였다. 광섬유 센서코일의 비틀림 정도를 달리하며 다양한 환경에서의 전류측정 실험을 행하였다. 실험결과로부터 광섬유 센서코일이 진동 등의 환경적 노이즈를 효율적으로 차단함을 알 수 있었으며 $\pm$3% 이내의 시스템 출력안정도를 얻었다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 추계학술대회 논문집
• /
• pp.951-954
• /
• 2000

This paper presents a new cutting method, i.e. diamond cutting, aided by electrolysis, in order to cut ferrous materials with diamond tools. Diamond cutting is widely applied in manufacturing ultraprecision parts such as magnetic disk, polygon mirror, spherical/non-spherical mirror and copier drum, etc. because of the diamond tool edge sharpness. In general, however, diamond cutting cannot be applied to cutting steels, because diamond tools wear excessively in cutting iron based materials like steel due to their high chemical interaction with iron in high temperature. In order to suppress the diffusion of carbon from the diamond tool and to reduce increase of cutting force due to size effect, we attempt to change chemically the compositions of iron based materials using electrolysis in a limited part which will be soon cut. Through experiments under several micro-machining and electrolysis conditions, cutting using electrolysis, compared to conventional cutting, was found to result in a great decrease of the cutting force, a better surface and much less wear tool.

• 전자공학회논문지A
• /
• 제31A권12호
• /
• pp.91-99
• /
• 1994

We used CMOS current mirror and differenial amplifier to find out how the degradation of each devices in circuit affect total circuit performance. The devices in circuit wer degraded by hot-carrier generated during circuit operation and total circuit performance were changed according to the change of each device parameters. To examine the circuit performance phenomena of current mirror, we analyzed three diffent kinds of current mirrors and made correlation model between circuit performance and stressed device parameters, and compare hot-carrier immunity of these circuits. Also we analyzed how the performance of differential amplifier degraded from the initial value after hot-carrier stress incircuit operations.

• 한국공작기계학회논문집
• /
• 제12권6호
• /
• pp.44-49
• /
• 2003

To obtain the surface roughness with range from 10nm to 1nm we need the study of ultra-precision machine, cutting condition, and materials. In this paper, the optimal cutting conditions for getting mirror surface of aluminum alloy have been examined experimentally by using ultra-precision turning machine and sing1e crystal diamond tool. In generally, the cutting conditions such as feed rate and depth of cut have effect on the surface roughness in ultra-precision turning. The result of surface roughness was measured by the ZYGO New View 200. Therefore, The surface roughness and cutting conditions has been clarified. The smooth surface of aluminum alloy less than 1nm RMS, 1nm Rmax can be obtained by the ultra-precision cutting.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2003년도 춘계학술대회 논문집
• /
• pp.416-421
• /
• 2003

To obtain the surface roughness with range from l0nm to In n need a ultra-Precision machine, cutting condition and the study of materials. And n have to also consider the chip and vibration of diamond tool during processing. In this paper, the cutting conditions for getting mirror surface of aluminum alloy have been examined experimentally by using ultra-precision turning and single crystal diamond tool. In generally, the cutting conditions have effect on the surface roughness in ultra-precision turning. The result of surface roughness was measured by the ZYGO New View 200.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제3권3호
• /
• pp.139-144
• /
• 2003

We report the results of extensive mixed mode simulations and theoretical analysis to quantify the contribution of the edge direct tunneling (EDT) current on the total gate leakage current of 80nm NMOSFET with SiO2 gate dielectric. It is shown that EDT has a profound impact on basic analog circuit building blocks such as sample-hold (S/H) circuit and the current mirror circuit. A transistor design methodology with zero gate-source/drain overlap is proposed to mitigate the EDT effect. This results in lower voltage droop in S/H application and better current matching in current mirror application. It is demonstrated that decreasing the overlap length also improves the basic analog circuit performance metrics of the transistor. The transistor with zero gate-source/drain overlap, results in better transconductance, input resistance, output resistance, intrinsic gain and unity gain transition frequency.