• 한국안광학회지
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• 제10권3호
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• pp.159-164
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• 2005

조절과 폭주기능은 밀접하게 연관된 합동운동으로 폭주와 조절 어느 한 쪽이 자극되면 양기능이 동시에 일어난다. 이 중 조절자극에 의해 일어나는 폭주를 조절성 폭주라고 하며, 눈의 굴절상태에 따라 과부족이 있다. 본 연구는 조절성 폭주비와 사위와의 관계를 규명하기 위해 그래디앤트(Gradient)법과 헤트로포리아(Heterophoria)법 둘 다 모두 사용하여 안과적 질환이 없는 성인 남녀 41명을 대상으로 검사하였다. 1. 원거리 사위분포를 조사한 결과, 정위 5명, 외사위 32명, 내사위 4명으로 외사위가 가장 많은 비율을 차지하고 있었다. 근거리 사위분포도는 원거리보다 넓게 퍼져서 분포하고 있었다. 2. 수정체의 조절력을 이완시킨 상태에서 수평사위량 측정시, 38명이 외사위량이 증가하였다. 3. 정상 AC/A ratio에 해당하는 $4{\sim}6{\Delta}/D$를 갖는 사람이 Heterophoria법에서는 27명으로 약 66%를, Gradient 법에서는 16명으로 39%를 각각 차지하고 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.354-356
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• 2001

The demand of the power and gas energy have been rapidly increasing with the industralization, therefore, the area where buried pipelines run parallel with the adjacent power lines and cross them increases in Seoul as well as other cities. These situation cause AC interference from the power lines. However, there aren't any standards to preserve the pipelines from AC interference in Korea. We just use other country's criteria directly. Other developed countries have used the various AC interference mitigation methods such as lumped grounding. cancellation wires and gradient control wires etc.. This paper introduces the steel plate method which is using for AC interference mitigation method in Korea and investigates the effects of mitigation methods through case study by computer simulation.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.185-186
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• 2000

For the quantitative investigation of the erosion of MgO layers in real ac-PDP cells, we constructed a microscopic spectrophotometer which is capable of measuring transmission spectra from the area as small as 20 ${\times}$ 20 ${\mu}m^2$. In the test on the sputtered MgO films with a thickness gradient, we were able to probe the thickness variation of 1000 nm over $1000-{\mu}m$ distance. Using this instrument, we were able to determine not only the erosion rate at the particular position of ac-PDP cells but also the relative erosion rate at different positions in a single ac-PDP cell.

• 한국안광학회지
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• 제19권3호
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• pp.345-351
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• 2014

목적: 각 사위 그룹에서 가입렌즈에 따른 조절반응량과 근거리 수평사위도의 변화를 측정하여 자극 AC/A비와 반응 AC/A비를 조사하였다. 이에 자극 AC/A비와 반응 AC/A비를 비교 분석하여 임상에서의 양안시 검사 및 처방시에 유용한 자료로 제시하고자 한다. 방법: 평균 만 $20.89{\pm}1.92$세, 81명을 대상으로 주시거리 40 cm에서 개방형 자동굴절계(Nvision-K 5001, Shin nippon)와 수정된 토링톤 시표(MIM card; Muscle Imbalance Measure card, Bernell)를 이용하여 양안시 상태에서 조절반응량과 근거리 수평사위도를 측정하였다. 그리고 측정된 값을 토대로 자극 AC/A비와 반응 AC/A비를 경사 AC/A법으로 계산하였다. 결과: 주시거리 40 cm에서 조절반응량은 외사위 그룹이 $1.92{\pm}0.26$ D로 가장 크고, 정위 그룹 $1.72{\pm}0.26$ D, 내사위 그룹 $1.62{\pm}0.42$ D 순으로 작아졌고, 근거리 수평사위도의 변화폭은 내사위 그룹이 $23.24{\Delta}$로 가장 크고, 정위 그룹 $19.76{\Delta}$, 외사위 그룹 $15.14{\Delta}$ 순으로 작게 나타났다. 가입렌즈에 따른 자극 AC/A비와 반응 AC/A비의 차이는 외사위 그룹에서는 -2.00 D 렌즈를 가입하였을 때, $1.72{\Delta}/D$로 가장 컸고 내사위 그룹에서는 +1.00 D 렌즈를 가입하였을 때 $3.43{\Delta}/D$로 가장 크게 나타났다. 외사위 그룹에서 -2.00 D, -1.00 D 렌즈를 가입하였을 때, 내사위 그룹에서는 +3.00 D, +2.00 D, +1.00 D, -1.00 D 렌즈를 가입하였을 때 각각 통계적으로 유의한 차이를 보였다. 결론: 자극 AC/A비와 반응 AC/A비를 비교하였을 때, 외사위 그룹에서는 (-) 렌즈를 가입하였을 때의 차이가 더 크고, 내사위 그룹에서는 (+) 렌즈를 가입하였을 때의 차이가 더 크게 나타났다. 또한 내사위 그룹의 자극 AC/A비와 반응 AC/A비의 차이가 외사위 그룹의 차이보다 더 크게 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.296-298
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• 1995

This paper proposes a new filter topology that suppresses the high voltage gradient(dv/dt) in ac motor terminals. The high voltage gradient(dv/dt) causes over voltages on the motor windings, the degradation or motor insulation, and the bearing failure. Moreover surge voltage with high voltage gradient(dv/dt) in the PWM inverter red drive system where long line cables are required causes more serious problem to the motor. Thus, the most advisable method is attaching output filter to the inverter output terminals. The conventional output filters have several problems such as bulky size, difficulty or parameter tuning. The proposed filter can be relatively smaller than the conventional filters. By the proposed filter, the shaping or PWM waveform can considerably suppress high dv/dt in motor feeding cable from the inverter. The effectiveness or the proposed filter is compared with that or the conventional one and is verified by the computer simulation.

• Journal of Microbiology
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• 제42권1호
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• pp.9-13
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• 2004

Culture-independent approaches, based on 16S rDNA sequences, are extensively used in modern microbial ecology. Sequencing of the clone library generated from environmental DNA has advantages over fingerprint-based methods, such as denaturing gradient gel electrophoresis, as it provides precise identification and quantification of the phylotypes present in samples. However, to date, no method exists for comparing multiple bacterial community structures using clone library sequences. In this study, an automated method to achieve this has been developed, by applying pair wise alignment, hierarchical clustering and principle component analysis. The method has been demonstrated to be successful in comparing samples from various environments. The program, named CommCluster, was written in JAVA, and is now freely available, at http://chunlab.snu.ac.kr/commcluster/.

• 전기학회논문지
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• 제58권1호
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• pp.77-85
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• 2009

With the advent of power semiconductor switching devices, power electronics relating to high frequency electromagnetic eddy current based induction heating technology have become more suitable and acceptable. This paper presents high-frequency induction heating cooking appliance circuit based on the zero current switching-PWM single ended push-pull(ZCS-PWM SEPP) resonant inverter added AC-DC converter. This inverter uses pulse-width-modulation(PWM) control method with active auxiliary quasi-resonant lossless inductor snubbers and a switched capacitor. To improved the transient performance, the PI controller is applied for this system. For the systematic parameter optimization of the PI controller, the gradient-based optimization algorithm is applied. The performance of optimized parameters is evaluated using simulation and experimental test. These results show that the proposed systematic optimal tuning method improve the transient performances of this system.

• 한국정밀공학회지
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• 제16권6호
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• pp.133-140
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• 1999

In this study, a monitoring method to detect chip disposal state in drilling system based on neural network was proposed and its performance was evaluated. If chip flow is bad during drilling, not only the static component but also the fluctuation of dynamic component of drilling. Drilling torque is indirectly measured by sensing spindle motor power through a AC spindle motor drive system. Spindle motor power being measured drilling, four quantities such as variance/mean, mean absolute deviation, gradient, event count were calculated as feature vectors and then presented to the neural network to make a decision on chip disposal state. The selected features are sensitive to the change of chip disposal state but comparatively insensitive to the change of drilling condition. The 3 layerd neural network with error back propagation algorithm has been used. Experimental results show that the proposed monitoring system can successfully recognize the chip disposal state over a wide range of drilling condition even though it is trained under a certain drilling condition.

• 디지털융복합연구
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• 제11권11호
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• pp.661-666
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• 2013

본 연구의 목적은 전북지역 성인들의 사위와 융합여력의 특성을 알아보자 하였다. 사시안, 안질환이 없는 20세에서 44세까지의 근시안을 가진 성인 116명을 대상으로 교정시력, 교정굴절력, 사위검사, 융합여력검사를 실시하였다. 프리즘분리법에 의한 수평사위검사에서 정위(26.7%) 외사위 (52.5%),내사위(20.7%)명이었다. 38.8%는 근거리에서 정상으로 간주되는 0-6${\Delta}$의 외사위를 가지고 있었고, 61.2%는 정상범위를 벗어난 사위를 가지고 있었다. 융합여력의 크기는 사위량이 많을수록 적어졌다. 사위안의 융합여력이 안정피로에 연관성이 있음을 알 수 있었고, 사위 처방시 융합여력을 검사하여야 할 것으로 생각된다. 또한 그래디앤트법으로 AC/A비를 측정한 결과 4.03이었으며, 굴절 이상과는 특별한 관계를 발견할 수 없었다.

• Journal of Pharmaceutical Investigation
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• 제38권1호
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• pp.57-61
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• 2008

A HPLC-ELSD method was developed to determine saikosaponin derivatives from Bupleuri Radix. Eight saikosaponins, saikosaponin c, i, h, a, $b_2$, g, $b_1$ and d, were analyzed under optimized HPLC conditions [column: Eclipse XDB $C_{18}$ ($150{\times}4.6mm$ i.d., $5{\mu}m$; mobile phase: $H_2O$ with 0.1% $CH_3$COOH (v/v) for solvent A and AcCN with 0.1% $CH_3$COOH (v/v) for solvent B, gradient elution; flow rate: 1mL/min; injection volume: $20{\mu}L$]. Good linearity was achieved in the range from 62.5 to $250{\mu}g/mL$ for each compound, and intra-day precision and accuracy at each concentration level varied between 0.05 and 5.45% and between 93.9 and 109.6%, respectively, whereas those for inter-day variations were between 0.91 to 2.73% and 94.3 to 106.1%. This HPLC-ELSD method was applied for the determination of sakosaponins from Bupleuri Radix samples, and saikosaponin a $(0.79{\pm}0.20mg/g)$, c $(0.33{\pm}0.06mg/g)$ and d $(0.48{\pm}0.15mg/g)$ were observed as major compounds. The other saikosaponins were shown under limit of quantification level thus couldn't be quantified. The present study suggested that the introduced HPLC-ELSD method is selective and reliable, and not only saikosaponin a, but also saikosaponin c and d should be employed as the standard markers for Bupleuri Radix.