• Journal of the Korean Ceramic Society
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• v.41 no.5
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• pp.370-374
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• 2004

Sr$_{l-x}$Ba$_{x}$Al$_2$O$_4$:Eu (x = 0, 0.1, 0.2, and 0.3 mol) phosphor was synthesized by the hydrothermal method and its properties of photoluminescence and long-afterglow were investigated. The mixtures of Sr(NO$_3$)$_2$, Al(NO$_3$)$_3$9$H_2O$, and Eu(NO$_3$)$_3$$.$6$H_2O$ salts dissolved in distilled water, after controlling their pH by NH$_4$OH solution, put into an Autoclave reactor with high temperature and pressure to react. Such synthesized SrAl$_2$O$_4$:Eu powders showed homogeneous and ultra-fine particles of sub-micron size. In order to have the photoluminescence characteristic, powders were heat treated at 1100 -140$0^{\circ}C$ for 2 h in Ar/H$_2$ reduction atmosphere. Photoluminescence spectra showed a excitation along the wide wavelength of 250 ∼ 450 nm, and broaden emission with maxima peak at 520 nm. Also, it showed a good long afterglow with decaying over 1000 sec after excitation illumination for 10 min. In addition, the microstructure and crystal structure of SrAl$_2$O$_4$:Eu powders were investigated by an SEM and XRD, respectively.

• Korean journal of applied entomology
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• v.39 no.4
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• pp.251-258
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• 2000

These studies were conducted to investigate the prey consumption and suppression of cotton aphid and green peach aphid by Chrysopa pallens Ramber as a predator. The 3$^{rd}$ instar of C. pallets fed on 29.8, 77.9, 133.6, and 155.7 individuals of apterous Aphis goussypii Glover a day at 17,22, 27, and 32$^{\circ}C$, respectively. A preovipositing female fed on 73.1 individuals, ovipositing female on 86.6 individuals, and adult male on 69.7 individuals of apterous Myzus persicae (Sulzer) a day at the 27$^{\circ}C$. The functional response curve of the larvae and adults of C. pallens to the densities of A. gossypii indicated Helling’s Type II: the consumption of prey by the C. pallens increased with the prey density but the consumption rate decreased. The attack rate of 3rd instar of C. pallens was the highest among the 2nd instar, 3$^{rd}$ instar, adult male and adult female, and handling time was the shortest. The critical ratio of the predator vs. the prey to effectively suppress the population of A. gossypii by releasing C. pallets eggs was 1 : 4 on red pepper and egg plant, and 1 : 3 on cucumber. Release of second larval stave of C. pallens at the ratio of 1 : 30 of the predator vs. the prey controlled satisfactorily A. gossypii on red pepper, and 1 : 20 on cucumber and tomato. The three-times introduction of the eggs of C. pallens was as effective as four applications of insecticides from mid-June to late September.r.

• The Journal of Society for e-Business Studies
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• v.23 no.1
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• pp.1-22
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• 2018

The value chain has been utilized as a strategic tool to improve competitive advantage, mainly at the enterprise level and at the industrial level. However, in order to conduct value chain analysis at the enterprise level, the client companies of the parent company should be classified according to whether they belong to it's value chain. The establishment of a value chain for a single company can be performed smoothly by experts, but it takes a lot of cost and time to build one which consists of multiple companies. Thus, this study proposes a model that automatically classifies the companies that form a value chain based on actual transaction data. A total of 19 transaction attribute variables were extracted from the transaction data and processed into the form of input data for machine learning method. The proposed model was constructed using the Random Forest algorithm. The experiment was conducted on a automobile parts company. The experimental results demonstrate that the proposed model can classify the client companies of the parent company automatically with 92% of accuracy, 76% of F1-score and 94% of AUC. Also, the empirical study confirm that a few transaction attributes such as transaction concentration, transaction amount and total sales per customer are the main characteristics representing the companies that form a value chain.

• Korean journal of applied entomology
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• v.53 no.4
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• pp.491-495
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• 2014

Mites were collected from organic cultivations of greenhouse cucumbers and identified as Tyrophagus neiswanderi (Acari: caridae). T. neiswanderi (length, $490.1{\mu}m;$ width, $288.1{\mu}m$) is a very small, milky-white, and egg-shaped mite, and it mainly causes damage to the leaves, flowers, and fruits of cucumber plants. In the early growing season of cucumbers, the shoots of seedlings became pale and yellow because of T. neiswanderi, and eventually shrinkage or bud-failing was observed in the plants. In the middle of the growing season, T. neiswanderi caused white spots on the leaves and flowers of the plants, and the spots gradually became holes. T. neiswanderi also caused severe damage to young fruits by feeding on the rinds of the fruits, inducing malformations and lowering the economic value.

• Research in Plant Disease
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• v.15 no.1
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• pp.30-35
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• 2009

This study was carried out to determine the causal agents of soil-borne fungal diseases that pose a threat to the muskmelon production in Cheong Yang, Korea and to investigate the potential effects of hot water drenching and three fumigant (metam sodium, dazomet and methyl bromide) on these diseases. As the agents of the diseases, Monosporascus cannonballus, Didymella sp., Fusarium sp., Phytophthora sp., were detected. Hot water and the fumigants were treated on two successive cropping seasons of melon. Soil temperature was measured at 0, 10, 20 and 30 cm soil depth. In 2005, soil sterilization by hot-water was more effective significantly to control of the diseases than by fumigant. yield was the highest in hot-water sterilized plot as $39\;ton{\cdot}ha^{-1}$. Dazomet ($50\;g/m^2$) treated plot was followed as $23\;ton{\cdot}ha^{-1}$. In 2006, hot water sterilized plot showed higher yields than non-treated plots ($14.8\;ton{\cdot}ha^{-1}$). But the other three fumigant contained Dazomet ($50\;g/m^2$) were no difference (P<0.05) in yield.

• Research in Plant Disease
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• v.26 no.2
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• pp.103-108
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• 2020

Evaluations were made for the effects of cheese whey treatment on infection of pepper plants by cucumber mosaic virus-Vch (CMV-Vch) and pepper mottle virus-Kr (PepMoV-Kr). In a greenhouse, pepper plants sprayed with whey, prior to inoculation by CMV-Vch using aphids, showed a viral infection rate significantly lower (6.6%) than for the control (23.3%). In an open field experiment, in which CMV infection relied on natural transmission by aphids, pepper plants were sprayed with undiluted whey once a week, starting on the transplanting date (May 2) to the end of June. On June 5, these whey-sprayed plants showed a CMV infection rate reduced by 18.9% and 16.7%, compared to untreated and pesticide-treated plants, respectively. In the greenhouse, pepper plants inoculated with PepMoV-Kr mixed with whey showed a viral infection rate decreased by 60% compared to the control. The accumulated amount of PepMoV-Kr coat protein was less than that for the virus-only control at 6 days post inoculation (dpi), but increased up to a similar level as the control at 9 dpi. This study showed that cheese whey is effective in reducing infection of both CMV and PepMoV in pepper plants.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.653-657
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• 2002

The hydrolysis conditions (enzym $e_strate ratio, time and temperature) of the mixture of anchovy sauce residue (ASR) and soy sauce residue (SSR) after fermentation by Flavourzyme 500M $G^{TM}$ were optimized using response surface methodology (RSM) for pretreatment of processing functional enzyme-hydrolyzed sauce. A model equation obtained from RSM was hydrolysis ratio (%) = 28.157+1.929enzym $e_strate ratio+1.818time+2.038temperature-1.093temperatur $e^2$, whose stationary point showed saddle point. From the ridge analysis of the saddle point, the conditions producing the highest hydrolysis ratio was determined as follows: 0.49% enzym $e_strate ratio; 3.55hr hydrolysis time; 62.5$^{\circ}C$ hydrolysis temperature. Adding of SSR to the mixture of water and ASR improved sensory qualities of mixture, so it seemed that SSR has masking effects on off-flavor and taste of ASR.R.of ASR.R.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.4
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• pp.114-131
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• 1992

In the present work, a two-dimensional boundary-value problem for a large amplitude motion is treated as an initial-value problem by satisfying the exact body-boundary and nonlinear free-surface boundary conditions. The present nonlinear numerical scheme is similar to that described by Vinje and Brevig(1981) who utilized the Cauchy's theorem and assumed the periodicity in the horizontal coordinate. In the present thesis, however, the periodicity in the horizontal coordinate is not assumed. Thus the present method can treat more realistic problems, which allow radiating waves to infinities. In the present method of solution, the original infinite fluid domain, is divided into two subdomains ; ie the inner and outer subdomains which are a local nonlinear subdomain and the truncated infinite linear subdomain, respectively. By imposing an appropriate matching condition, the computation is carried out only in the inner domain which includes the body. Here we adopt the nonlinear scheme of Vinje & Brevig only in the inner domain and respresent the solution in the truncated infinite subdomains by distributing the time-dependent Green function on the matching boundaries. The matching condition is that the velocity potential and stream function are required to be continuous across the matching boundary. In the computations we used, if necessary, a regriding algorithm on the free surface which could give converged stable solutions successfully even for the breaking waves. In harmonic oscillation problem, each harmonic component and time-mean force are obtained by the Fourier transform of the computed forces in the time domain. The numerical calculations are made for the following problems. $\cdot$ Forced harmonic large-amplitude oscillation(${\omega}{\neq}0,\;U=0$) $\cdot$ Translation with a uniform speed(${\omega}=0,\;U{\neq}0$) The computed results are compared with available experimental data and other analytical results.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.394-399
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• 2005

Near Infrared Spectroscopy (NIRS) has been used as a tool for the rapid, accurate and nondestructive assay of the fresh rice leaf in nitrogen content. NIRS used in this study was visible and near infrared spectroscopy type instrument, Foss model 6500. To obtain a useful calibration equation, standard regression between the data was analyzed by chemical analysis and by NIRS method. Accuracy of calibration equation for nitrogen content on fresh leaf of rice were 0.879, 0.858 and 0.819, respectively. Accuracy of calibration equation after outlier treatment increased as 0.017, 0.02 and 0.061 improved each with 0.896, 0.878 and 0.880, respectively. Calibration equation combined using merge function after accuracy of calibration equation more increased by 0.911. Difference analysis value between calibration equation and lab value by kjeldahl showed $0.001\%$. With this as same result is the possibility of closing the deterioration of the sample in order to omit a construction and pulverization process it is judged with the fact that the nitrogen content measurement of the fresh rice leaf which the possibility of reducing an hour and an expense is by a near infrared spectroscopy technique will be possible.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.3
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• pp.217-222
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• 1996

The moving behaviour of anchovy schools(There were small schools of sardine and round-herring in this anchovy schools} in the bag - net of a large scale set - net was investigated using a scanning sonar, in the Kishihata set - net fishing ground located in Nanao city Ishigawa prefecture, Japan from Dec. 1st to Dec. 4th, 1992. The results obtained are summarized as follows ; 1. Moving behaviour of fish schools between two bag - nets was more in the daytime than in the nighttime. 2. The rate of entering fish schools from the first bag -- net to the second bag - net were 78% when the fish school in the second bag -- net existed. The result suggest that fish school existence in the second bag - net affected the rate of entering fish schools from the first bag - net to the second- bag - net. However, the time of stay of fish school that entered the second bag -- net was very short when the fish school in the second bag - net existed densely. The result suggest that a high fish density in the second bag - net might enlarge the escape rate 3. The majority of fish schools moved to the center and off shore side of the bag - net when fish schools entered the bag - net.