• Journal of Environmental Science International
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• v.12 no.1
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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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1785-1796
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• 1998

This paper is concerned with the relationships between optimal number of wavelengths and tuning time in time division multiplexing(TDM) scheduling on wavelength division multiplexing(WDM) optical passive star networks. We assume that the traffic is nonuniform and each node has a tunable transmitter and a fixed receiver. Each node transmits spckets to all other nodes. Most of the earlier protocols on TDM based scheduling for WDM star networks [7, 8, etc.] use whold given wavelength chnnels. But in this paper, we investigate the optimal number of wavelengths that yidels minimum frame length when tuning time exists. It appears within the availble number of wavelengths that yields minimum frame length when tuning time exists. It appears within the available number of wavelengths. We analyze the relationships between optimal number of wavelengths and tuning time by experiments. We analyze the reationships between optimal number of wavelengths and tuning time by experiments. We also discuss on the possibility of reduction of frame length by increasing the number of nodes trans-mitters and receivers.

• Transactions on Electrical and Electronic Materials
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• v.11 no.6
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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%).

• Journal of the Korea Society of Computer and Information
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• v.20 no.1
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• pp.111-118
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• 2015

This paper deals with the routing and wavelength assignment problem (RWAP) that decides the best lightpaths for multiple packet demands for (s,t) in optical communication and assigns the minimum number of wavelengths to given lightpaths. There has been unknown of polynomial-time algorithm to obtain the optimal solution for RWAP. Hence, the RWAP is classified as NP-complete problem and one can obtain the approximate solution in polynomial-time. This paper decides the shortest main and alternate lightpath with same hop count for all (s,t) for given network in advance. When the actual demands of communication for particular multiple packet for (s,t), we decrease the maximum utilized edge into b utilized number using these dual-paths. Then, we put these (s,t) into b-wavelength bins without duplicated edge. This algorithm can be get the optimal solution within O(kn) computational complexity. For two experimental data, the proposed algorithm shows that can be obtain the known optimal solution.

• Journal of the Korean Society of Visualization
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• v.12 no.3
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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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.5
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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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.1051-1058
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• 1998

We propose a bandpass filter using wavelength selectivity as variation of writing beam incident angle in photorefractive crystal. From TWM(Two-Wave Mixing) experiment, optimal diffraction properties are induced, and bandpass filter for selection wavelength transmission bandwidth are taken by change of writing beam incident angle.

• Journal of Veterinary Clinics
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• v.6 no.2
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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.

• Korean Journal of Agricultural Science
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• v.41 no.1
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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.

• Journal of the Korean Operations Research and Management Science Society
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• v.26 no.1
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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.