• 한국환경과학회지
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• 제12권1호
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• pp.87-92
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• 2003

Synchronous spectrofluorimetry was carried out for the simultaneous determination of various polycyclic aromatic hydrocarbons(PAHs) in aqueous solution by fluorescence spectrometry have been studied. The optimal wavelength interval(${\triangle}{\lambda}$) for synchronous spectra of acenaphthene, anthracene, benzo[a]anthracene, fluorene and pyrene were investigated in the presence of surfactants. The great enhancement of the fluorescence of these PAHs in Triton X-100 was obtained and optimal wavelength was 50 nm. The calibration curves in synthetic mixture solution of 5 PAHs were linear over the range from $1.0{\times}10^{-8}M$ to $1.0{\tiems}10^{-4}M$. Under the optimal experimental conditions, the detection limits were $4.9{\tiems}10^{-9}M$,\;7.0{\times}10^{-9}M,\;4.7{\tiems}10^{-9}M,\;1.6{\tiems}10^{-9}M$ and $3.2{\tiems}10^{-9}M$ for acenaphthene, anthracene, benzo[a]anthracene, fluorene and pyrene, respectively.

• 한국통신학회논문지
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• 제23권7호
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• pp.1785-1796
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• 1998

본 논문에서는 WDM(wavelength division multiplexing) 수동 성형망(passive star network) 환경에서 TDM(time d division multiplexing) 방법을 기반으로 한 타임슬롯 스케률링시의 최적파장수와 파장조정시간{tuning time)과의 관계에 대해 분석한다. 여기서는 각 노드들이 한 개 씩의 파장조정 송신기(tunable transmitter)와 파장고정 수신기(fixed receiver)를 갖추고 있고, 전송 트래픽은 비균등(nonuniform)이며, 각 노드들은 자신을 제외한 나머지 모든 노드들로 패킷을 전솜함을 가정한다. 기존의 스케률링 방법[7, 8, etc.]에서는 주어진 파장수를 전부 이용하였으나, 본 논문에 서는 부하균형(load balancing)을 포함한 순서 스케줄링(list scheduing) 사용시 프레임 길이를 최소로 하는 '최적 파 장수'가 이용 가능한 파장수 이하의 범위에서 존재함을 실험을 통해 보이고, 파장조정시간과의 관계를 분석한다. 또한 각 노드의 송신기(transmitter)와 수신기(receiver) 수의 증가에 의한 프레임 길이 단축 가능성에 대해 분석한다.

• Transactions on Electrical and Electronic Materials
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• 제11권6호
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• pp.279-284
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• 2010

This study has been carried out to determine the optimal process conditions of $AZO:H_2$ thin films for the maximization of the transmittance of a blue GaN light-emitting diode (LED) with a wavelength of 470 nm. The Al-doped zinc oxide $(AZO):H_2$ thin films were deposited on a sapphire substrate by radio-frequency magnetron sputtering system with varying substrate temperatures, working pressures and annealing temperatures temperature, working pressure and annealing imposed on a AZO (2wt% $Al_2O_3$) ceramic target. The effect of these variables was investigated in order to improve the light extraction efficiency of the LED. As a result, the (002)-oriented peak was found in all the $AZO:H_2$ thin films. The lowest resistivity and the best transmittance at a wavelength of 470 nm was found to be $4.774\;{\times}\;10^{-4}\;{\Omega}cm$ and 92% at a substrate temperature of $500^{\circ}C$, working pressure of 7 mTorr and annealing temperature of $400^{\circ}C$. The transmittance of the $AZO:H_2$ thin film for the Blue GaN LED was improved by approximately 13% relative to that of a ITO thin film (T = 79%).

• 한국컴퓨터정보학회논문지
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• 제20권1호
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• pp.111-118
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• 2015

본 논문은 광통신망에서 (s,t)에 대한 다중 패킷 통신 요구에 대해 최적의 광 경로를 설정하고, 최소 파장 수를 배정하는 경로설정과 파장 배정 문제 (RWAP)를 다룬다. RWAP는 지금까지 다항시간으로 최적 해를 구하는 알고리즘이 알려져 있지 않은 NP-완전으로 근사 해를 다항시간으로 구하고 있다. 본 논문은 주어진 망의 모든 (s,t)에 대해 최단 광 경로로 동일한 홉 수를 갖는 주경로와 대체경로를 사전에 결정하고, (s,t)에 대한 실제 특정 다중 패킷 통신이 요구될 때 이들 이중 경로를 이용하여 최대로 이용되는 간선의 이용횟수를 b개로 줄이고, b개의 파장 수 상자에 중복 간선 없이 담는 방법으로 O(kn) 계산 복잡도로 최적 해를 구할 수 있었다. 2개의 실험 데이터 망에 적용한 결과, 제안된 알고리즘은 기존에 알려진 최적 해를 얻을 수 있음을 보였다.

• 한국가시화정보학회지
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• 제12권3호
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• pp.9-14
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• 2014

Two-photon microscopy (TPM) has been used in plant research as a high-resolution high-depth 3D imaging modality. However, TPM is known to induce photo-damage to the plant in case of long time exposure, and optimal excitation wavelength for plant imaging has not been investigated. Longer excitation wavelength may be appropriate for in vivo two-photon imaging of Arabidopsis thaliana leaves, and effects of longer excitation wavelength were investigated in terms of imaging depth, emission spectrum. Changes of emission spectrum as a function of exposure time at longer excitation wavelength were measured for in vivo longitudinal imaging. Imaging depth was not changed much probably because photon scattering at the cell wall was a limiting factor. Chloroplast emission spectrum showed its intensity peak shift by 20 nm with transition of excitation wavelength from 849 nm or below to 850 nm or higher. Emission spectrum showed different change patterns with excitation wavelengths in longitudinal imaging. Longer excitation wavelengths appeared to interact with chloroplasts differently in comparison with 780 nm excitation wavelength, and may be good for in vivo imaging.

• 한국기계가공학회지
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• 제13권5호
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• pp.98-106
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• 2014

This study was carried out to evaluate the plant growth rate according to the wavelength characteristics of LED light sources. In order to achieve this, red, green, blue and white LEDs were arrayed in a rectangle array consisting of LED modules which can be combined with each other.. This can facilitate the selection of the optimal characteristics of the light from monochromatic red, green, blue and white LEDs or mixed LEDs for plant growth. Experiments to evaluate the growth rate according to the wavelength characteristics of the LEDs with several plants, in this case ice plants, lettuce, barley, broccoli and chives, were performed.

• 한국통신학회논문지
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• 제23권4호
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• pp.1051-1058
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• 1998

광굴절결정에서 두 기록빔의 입사각에 따른 파장선택성을 이용해 원하는 통과대역과 중심파장을 갖는 대역통과필터로의 응용을 제안하였다. 2광파결합을 통해 Fe가 0.02Wt.% 도핑된 $LiNbO_3$ 결정의 회절특성을 실험함으로써, 가장 우수한 회절효율을 갖는 조건을 도출하고, 이러한 조건에서 원하는 대역 및 파장을 선택해 낼 수 있는 대역통과필터를 전광학적으로 구현하였다. 또한, 기록빔의 입사각을 변화시킴으로써, 임의의 원하는 필터 특성을 얻을 수 있음을 실험적으로 증명하였다.

• 한국임상수의학회지
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• 제6권2호
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• pp.291-305
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• 1989

Present experiment was performed to establish the optimal reaction conditions for measurement of urinary gamma-glutamyltranspeptidase(${\gamma}$-GTP), N-acetyl-${\beta}$-D-glucosaminidase (AGS) and alanine aminopeptidase(AAP) activities in bovine and to investigate in vitro stability of the enzymes, within-run imprecision of the methods, and normal ranges. 1. The optimal wavelength for measurement of ${\gamma}$-GTP activity was 545nm. 2. The optimal pH of Tris-HCI buffer containing glycylglycine for measurement of urinary ${\gamma}$-GTP activity was 7.6～7.8(37$^{\circ}C$). 3. Coefficient of variance for within-run imprecision of urinary ${\gamma}$-GTP activity ranged from 4.8 to 7.2% and there was no significant difference among replications, 4. The optimal wavelength for measurement of urinary AGS activity was 405nm. 5. The optimal pH of citrate buffer for measurement urinary of AGS activity was 4.0(37$^{\circ}C$). 6. Coefficient of variance for within-run imprecision of urinary AGS activity ranged from 3.9 to 6.1％ and there was no significant difference among replications. 7. The optimal wavelength for measurement of urinary AAP activity was 400nm. 8. The optimal pH of phosphate buffer for measurement of urinary AAP was 7.8. 9. Coefficient of variance for within-run imprecision of urinary AAP activity ranged from 2.5 to 4.8% and there was no significant difference among replications. 10. ${\gamma}$-GTP and AGS activities were increased significantly by gel-filtration. 11. Turbidity interfered with measurement of urinary AAP activity in bovine unless the specimen was gel-filterated. 12. Preservation of the specimen at 5$^{\circ}C$ or -20$^{\circ}C$ did not affect the AGS activity at least for 7 days after collection. 13. Preservation of the specimen at 5$^{\circ}C$ or 20$^{\circ}C$ did not affect the ${\gamma}$-GTP and AAP activities statistically, but some individual specimens revealed fluctuation during preservation. 14. ${\gamma}$-GTP, AGS and AAP activities revealed fluctuation by the tine of the day when the specimen was collected. 15. The normal ranges of urinary ${\gamma}$ -GTP, AGS and AAP activities were 6.60${\pm}$3.26(2.36-14.50), 1.31 ${\pm}$ 0.81(0.33-3.78), and 1.73 ${\pm}$ 0.55(0.77-3.03)U/l. respectively.

• 농업과학연구
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• 제41권1호
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• pp.59-63
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• 2014

Precision farming aims at reduced environmental impacts with increased productivity. Soils are multi-functional media in which air, water and biota occur together and form an essential part of the landscape with a fundamental role in the environment. The requirement for herbicides and fertilizers can vary within a field in response to spatial differences in soil properties. Near infrared (NIR) spectroscopy is widely used today as a nondestructive analytical technique which is capable of determining a number of physio-chemical parameters. The objectives of this study were to develop optimal models to predict chemical properties of paddy soils by visible and NIR reflectance spectra. Total of 60 soil samples were collected in spring from 20 paddy fields within central regions in Korea. Reflectance spectra, moisture contents, pH, total nitrogen (N), organic matter, available phosphate ($P_2O_5$) of soil samples were measured. The reflectance spectra were measured in wavelength ranges of 400-2,500 nm with 2 nm interval. The method of partial least square (PLS) analysis was used to determine the soil properties. The PLS analyses showed good correlation between predicted and measured chemical properties of paddy soils in the wavelength range of 1,800-2,400 nm. Especially, it showed better performance than the previous results which used the entire wavelength range of the spectrophotometer, without considering the optimal wavelength of each soil properties.

• 한국경영과학회지
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• 제26권1호
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• pp.33-44
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• 2001

In this paper, we address a problem of traffic grooming and wavelength routing in all optical WDM ring networks. Given a traffic demand for each node pair, we should aggregate the traffic onto lightpaths between pairs of nodes to transport the demand, and set up the routing path for each lightpath with minimum number of wavelengths to be assigned to lightpaths. In this paper, we formulate our problem as a mixed Integer Programming model. Owing to the problem complexity, it is hard to find an optimal solution for our problem. hence, we develop a heuristic algorithm to solve our problem efficiently. From the computational experiments, we can find the proposed heuristic is very satisfactory in both the computation time and the solution quality generated.