• Journal of the Optical Society of Korea
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• 제18권1호
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• pp.65-70
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• 2014

This paper presents the simulation and design of an all-optical subtractor using a quantum-dot semiconductor optical amplifier Mach-Zehnder interferometer (QD-SOA MZI) structure consisting of two cascaded switches, the first of which produces the differential bit. Then the second switch produces the borrow bit by using the output of the first switch and the subtrahend data stream. Simulation results were obtained by solving the rate equations of the QD-SOA. The effects of QD-SOA length, peak power and current density have been investigated. The designed gate can operate at speeds of over 250 Gb/s. The simulation results demonstrate a high extinction ratio and a clear and wide-opening eye diagram.

• Journal of the Optical Society of Korea
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• 제17권1호
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• pp.38-43
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• 2013

In this study, we propose a simple and indirect method to determine the optical constants of Mo and ITO thin films in the extreme ultraviolet (EUV) wavelength region by using X-ray reflectometry (XRR) and Rutherford backscattering spectrometry (RBS). Mo and ITO films were deposited on silicon substrates by using an RF magnetron sputtering method. The density and the composition of the deposited films were evaluated from the XRR and RBS analysis, respectively and then the optical constants of the Mo and ITO films were determined by an indirect optical method. The results suggest that the indirect method by using the XRR and RBS analysis will be useful to search for suitable high absorbing EUVL mask material quickly.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제34권3호
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• pp.325-340
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• 2008

The purpose of this study was to evaluate the artificial dental plaque by Streptococcus mutans on 4 different implant surfaces. In this study, the specimens were divided into 4 groups according to implant surface treatment. Uncoated implant group(n=5) which has an uncoated, smooth surfaced implant(Osstem, Korea), SLA implant group(n=5) which has an sandblasted large grit and acid-etched surface implant(Bicon, USA). Oxidized implant group(n=5) which has an oxidized surfaced implant (Osstem, Korea), and RBM implant group(n=5) which has resorbable blasting media(RBM) surfaced implant(Osstem, Korea). Acquired pellicle by human saliva and dental plaque by Streptococcus mutans were made on each implant surface. To analyze the plaque condition on implants surfaces, cell count and optical density were taken as a microbiologic method, and SEM(Scanning Electronic Microscope) findings was also taken for evaluation of surface condition. The following results were obtained. 1. Cell counting results of artificial dental plaque were Uncoated group($658.0{\pm}102.0$), RBM group($878.0{\pm}170.0$), SLA group ($946.0{\pm}42.0$), Oxidized group($992.0{\pm}40.0$), and there was difference between Oxidized group and Uncoated implant group(p<0.05). In case of modified cell counting results by v/w% were RBM group($197.8{\pm}45.2$), Oxidized group($207.04{\pm}8.34$), Uncoated group($261.6{\pm}40.6$), SLA group($315.4{\pm}14.0$), and there was difference between RBM group and SLA group(p<0.05). 2. Optical density results of artificial dental plaque after ultrasonic treatment was that there was difference among groups, and optical density of RBM group was higher than that of Uncoated group(p<0.05). In case of modified optical density results by v/w%, there was difference among groups, and the modified optical density of Uncoated group and SLA group was higher than those of Oxidized group and RBM group(P>0.05). 3. SEM findings of artificial dental plaque on the surfaces of implant as follows; there were artificial dental plaque on the surfaces of all test implants. Streptococcus mutans and by-product were observed at 10,000 times magnified condition on all test implants. Adhesion area of artificial dental plaque was about 1/2 of total surface after 24 hours incubate at $37^{\circ}C$. These results showed that there were differences among implant surfaces on the growth of Streptococcus mutans, and bacteria and by-product were covered about 1/2 area of total implant surfaces at 24 hours incubate at $37^{\circ}C$.

• Journal of Acupuncture Research
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• 제19권3호
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• pp.95-106
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• 2002

The present study was designed to investigate the effects of various electroacupuncture(EA) stimulation on NADPH-diaphorase and Neuropeptide Y(NPY) in the cerebral cortex of Sprague-Dawley Rats. We evaluated the changes of NADPH-d-positive neurons using a histochemical method and the changes of NPY-positive neurons using a double labeling immunohistochemical method. The staining intensities of NADPH-d-positive neuron and NPY-positive neurons were assessed in a quantitative fashion using a microdensitometrical method based on optical density by means of an image analyzer. As to frequency, the optical density of NADPH-d-positive neurons of 2Hz-1 time EA group was significantly higher than that of 100Hz-1 time EA group in M1, Cg, and that of 100Hz-3 times EA group was significantly higher than that of 2Hz-3 times EA group in Vi, Au, Cg and Ins. As to treatment-time, the optical density of NADPH-d-positive neurons of 2Hz-1 time EA group was higher than 2Hz-3 times EA group in Vi, Au, Cg and Ins. And in Vi 100Hz-1 time EA group and in M1 100Hz-3 times EA group was more efficient. As to frequency, the optical density of NPY-positive neurons of 2Hz-1 time was significantly higher in Vi, and that of 100Hz-1 EA group was higher in M1. And that of 2Hz-3 times EA group was higher than 100Hz-3 times EA group in Cg. As to treatment-time, the optical density of NPY-positive neurons of 2Hz-1 time EA group was significantly higer than 2Hz-3 times EA in S1, Vi, Au. And that of 100Hz-1 time EA group was significantly higher than that of 100Hz-3 time EA in Cg. The present results demonstrated that EA changes the activity in NO and NPY system in the cerebral cortex of SHR and EA stimulation, like frequency and treatment-time, is of importance for this effect.

• 디지털융복합연구
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• 제17권12호
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• pp.393-398
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• 2019

본 연구에서는 잇솔질 후 헹굼 횟수에 따른 흡광도 및 pH 변화를 조사하여 구강 내 잔여 치약의 양을 확인하고 이를 통하여 적정 헹굼 횟수를 제시하고자 하였다. 연구대상자는 대전, K대학 대학생 중 일생생활에 지장이 없는 건강한 신체를 가진 학생 총 14명을 선정하였으며, 연구대상자는 잇솔질 후 0회부터 12회까지 40ml의 물로 입울 헹구었다. 각 헹굼액은 수거하여 흡광도 및 pH를 측정하였다. 헹굼액의 흡광도 값을 측정한 결과, 잇솔질 후 6 ~ 7회의 헹굼액부터 흡광도 값이 일정한 수치를 보이며 통계적으로 유의한 결과가 나타났다(p<0.05). 1g, 1.5g, 2g으로 달리한 치약의 양에 따라서는 차이가 없었다. 향후 이러한 결과를 바탕으로 세치제 사용에 관한 교육과 구강 내 잔여 세치제가 구강에 미치는 영향에 대한 다양한 연구가 필요할 것으로 사료된다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2007년도 The 1st International Symposium on Advanced Magnetic Materials
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• pp.309.2-309.2
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• 2007

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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• pp.276.1-277
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• 2000

Absorptive bistable laser diode was analyzed by using traveling wave model in conjunction with the finite-difference method. Carrier and photon density distributions were calculated and the output characteristics were obtained. The results for both the steady-state and transient (switching) cases were compared with those of the rate equation approach.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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• pp.54-55
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• 2000

매질의 성능이 이상적이라 가정하고, 여러 가지 시스템 파라미터로 2진 홀로그램을 저장하는 경우에 있어서, 얻을 수 있는 면적 저장밀도와 다중화 횟수를 산출하고 비교하였다. 이 논문의 결과들은 새로운 디스크형 3차원 홀로그래픽 메모리[1-3]를 연구하거나 매질을 개발함에 있어서 비교 지표로 사용될 수 있다.(중략)

• 한국광학회:학술대회논문집
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• 한국광학회 2007년도 동계학술발표회 논문집
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• pp.251-252
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• 2007

• 한국광학회:학술대회논문집
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• 한국광학회 2005년도 하계학술발표회
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• pp.278-279
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• 2005