• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1853-1856
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• 2003

Multi-layer printed circuit board(PCB) is being used widely for the product with relatively complex circuits such as TV, VTR and FAX. With the rapid enlargement of electronic and IT industry, the hole machining technology on multi-layer PCB is increasingly required to improve. Thus, the micro drilling with ultrasonic vibration can be a good method for hole machining. Unlike conventional drilling, ultrasonic vibration applied drilling introduces less wear and fracture of not only tool but also internal surface of workpiece due to little cutting resistance, thus, machinability can be improved. The experiment is conducted through the comparison between the results of conventional drilling and ultrasonic micro drilling as well as among each results by the variation according to not only feed rate of drill but also amplitude and frequency of ultrasonic vibration. The multi-layer PCB consists of 6 layers and ${\Phi}$0.3 diameter drill was used. As a result, it was found that the state of internal surfaces of holes on multiple layer PCBs is improved by the application of ultrasonic vibration.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.7
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• pp.1051-1056
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• 2002

In vitro binding efficacy of esterified glucomannan (E-GM) (0.1%) on aflatoxin B1 (AF) (300 ppb), ochratoxin A (OA) (2 ppm) and T-2 toxin (T-2) (3 ppm), when present alone or in combination, was evaluated in toxin-contaminated feed at pH 4.5 and 6.5. Esterified glucomannan showed significantly (p<0.01) higher binding with AF (81.6%), whereas those recorded with T-2 (27.8%) and OA (25.6%) were moderate. Binding of each toxin decreased as the number of toxins in feed increased. pH of medium showed no effect on mycotoxin binding ability of E-GM. A $2{\times}2{\times}2{\times}2$ factorial experiment of 5 week duration was conducted to study the effects of two dietary levels each of AF (0 and 300 ppb), OA (0 and 2 ppm), T-2 (0 and 3 ppm ) and E-GM (0 and 0.1%) on the immune competence of a total of 960 day-old commercial broilers. Reductions in size of thymus (by AF and T-2) and bursa (by AF) and antibody titers against Newcastle disease and Infectious Bursal disease (by all the toxins) were noted. Additive and antagonistic interactions were seen among the toxins on certain parameters. Esterified glucomannan significantly (p<0.01) improved antibody titers and weights of bursa ofFabricius and thymus indicating its counteracting efficacy against immunosuppression in mycotoxicosis of multiple origin.

• Journal of electromagnetic engineering and science
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• v.11 no.2
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• pp.97-104
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• 2011

A planar slotted waveguide array antenna has been designed at 9.37 GHz for X-band radar applications. The antenna consists of multiple branchline waveguides with broadwall radiating shunt slots and a main waveguide to feed the branch waveguides through a series of inclined coupling slots. The antenna feed point is located at the center of the main waveguide. Element weights in the array have been calculated bysampling a continuous circular Taylor aperture distribution at the 25 dB sidelobe level in both the E and Hplanes. A commercially available electromagnetic (EM) simulation tool has been used to characterize the individual isolated slot and that data hassubsequently been used to design the planar array. The array is finally analyzed in a CST Microwave studio and the measured and simulated results have been found to be in good agreement.

• The Korean Journal of Food And Nutrition
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• v.30 no.2
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• pp.319-325
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• 2017

In this study, we optimized the coffee extraction conditions for instant coffee production in two stage percolators, which is the most common coffee extractor for instant coffee production. A central composite design was used to build mathematical model equations for response surface methodology (RSM). In these equations, the yield and overall acceptability of the coffee extracts were expressed as second-order functions of three factors, the feed water temperature, draw-off factor (DOF), and extraction time (cycle time). Based on the result of RSM, the optimum conditions were obtained with the use of desirability function approach (DFA) which find the best compromise area among multiple options. The optimum extraction conditions to maximize the yield and overall acceptability over 40% of yield were found with $163^{\circ}C$ of feed water temperature, 4.3 of DOF and 27 minutes of extraction time (cycle time). These results provide a basic data for the coffee extraction conditions for the competitive instant coffee in the industry.

• Korean Journal of Poultry Science
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• v.28 no.1
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• pp.41-47
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• 2001

Two experiments were conducted to investigate the effents of feeding single or combined probiltics on performance and intestinal micreflora of broiler chicks for five weeks. Diets based on corn and soybean meal contained 21.50, 19% CP and 3,100, 3,150kcal/kg ME for starting and finishing period, respectively. Lactobacillus salvarius isolated from chicks intestine(LSC), Lactobacillus salvarius isolated from piglet(LSP), Bacillus polyfermenticus(BP) were fed with alone and mixed ones at the level of 0.21 and 0.1% in experiment 1 and 2, respectively. Three hundred eighty four chicks were randomly assigned to eight treatments with four replicates of 12 chicks each per treatment. Weight gain, feed consumption, feed conversion ratio(FCR) were weekly measured for 5 weeks. The number of intestinal micreflora was examined at the end of experiment. In both experiments, weight gain of chicks fed probiltics tended to be similar or higher than control, but was not in LSC+LSP treatment. Feed intake was not consistent among treatments. In experiment 1, FCR of chicks fed LSC alone was the lowest of all treatments, whereas it was significantly higher in LSC+LSP treatments than control(P〈0.05). In experiment 2, LSP supplemental groups tended to increase FCR compared to the control. The number of ileal E. coli was the lowest in LSP alone treatment of experiment 1, whereas cecal E. coli was higher concentration in probiotics supplemental groups than control. Total Lactobacillus of chicks fed probiotics was decreased in ileum, but was no consestency in cecum. In experiment 2, ileal total yeast tended to be higher in probiotics supplemental groups except LSP alone supplement than control. Total Lactobacillus of chicks fed LSC or LSP alone treatments was significantly higher than control(P〈0.05).

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.3
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• pp.395-404
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• 2019

Objective: Wheat bran (WB) and rice bran (RB) are the agricultural by-products used as poultry feed in many developing countries. However, their use for poultry feed is limited due to high fiber and the presence of anti-nutritional substances (e.g. ${\beta}-glucans$). The objective of this study was to develop a method to improve the quality of those brans by reducing the fiber content. Methods: A two-step fermentation method was developed where the second fermentation of first fermented dry bran was carried out. Fermentation was performed at a controlled environment for 3 h and 6 h (n = 6). The composition of brans, buffer solution and rumen liquor was maintained in a ratio of 1:2:3, respectively. Brans were analyzed for dry matter, crude fiber (CF), acid detergent fiber (ADF), neutral detergent fiber (NDF), and acid detergent lignin (ADL) content. Celluloses and hemicelluloses were calculated from the difference of ADF-ADL and NDF-ADF, respectively. Samples were compared by two-factor analysis of variance followed by Tukey's multiple comparison tests (p<0.05). Results: CF %, ADF % and cellulose tended to decrease and NDF % and hemicellulose content was reduced significantly (p<0.05). After the 1st fermentation step, NDF decreased $10.7%{\pm}0.55%$ after 3 h vs $17.0%{\pm}0.78%$ after 6 h in case of WB. Whereas, these values were $2.3%{\pm}0.30%$ (3 h) and $7.5%{\pm}0.69%$ (6 h) in case of RB. However, after the 2nd fermentation step, the decrease in the NDF content amounted to $9.1%{\pm}0.72%$ (3 h), $17.4%{\pm}1.13%$ (6 h) and $9.3%{\pm}0.46%$ (3 h), $10.0%{\pm}0.68%$ (6 h) in WB and RB, respectively. Cellulose and hemicellulose content was reduced up to $15.6%{\pm}0.85%$ (WB), $15.8%{\pm}2.20%$ (RB) and $36.6%{\pm}2.42%$ (WB), $15.9%{\pm}3.53%$ (RB), respectively after 2nd fermentation of 6 h. Conclusion: Two-step fermentation process improved the quality of the brans for their use in poultry feed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.6A
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• pp.414-424
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• 2003

In this paper, a multiple U-shaped slot antenna for 5.25㎓~5.35㎓ is designed, fabricated, and measured. The prototype consists of U-slot and two invert U-slot. To obtain enough bandwidth, the foam layer is inserted between ground plane and substrate. Important parameters in the design are U-slot length, width, position, airgap length, and feed point. From these parameters optimized, a multiple U-shaped slot antenna is fabricated and measured. The measured results of the antenna are compared with its simulated results. The resonant frequency of the fabricated multiple U-shaped slot antenna is 5.25㎓ the bandwidth for approximately 7.4%(VSWR<1.5) and the gain is 2.9~5.3dBi. The experimental far-field patterns are stable across the pass band. The 3dB bandwidth in H-Plane and I-Plane are 62$^{\circ}$ and 50$^{\circ}$, respectively.

• Bulletin of the Korean Chemical Society
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• v.33 no.5
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• pp.1703-1706
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• 2012

Rice blast is the most serious disease of rice due to its harmfulness and its world wide distribution. $Magnaporthe$ $grisea$ is the cause of rice blast disease and destroys rice enough to feed several tens of millions of people each year. Fungicides are commonly used to control rice blast. But $M.$ $grisea$ acquires resistance to chemical treatments by genetic mutations. 2-Phenylimino-1,3-thiazolines were proposed as a novel class of fungicides against $M.$ $grisea$ in the previous study. To develop compounds with a higher biological activity, a new series of 2-phenylimino-1,3-thiazolines was synthesized and its fungicidal activity was determined against $M.$ $grisea$. The QSAR analysis was carried out on a series of 2-phenylimino-1,3-thiazolines. The QSAR results showed the dependence of fungicidal activity on the structural and physicochemical features of 2-phenylimino-1,3-thiazolines. Our results could be used as guidelines for the study of the mode of action and further design of optimal fungicides.

• Water Engineering Research
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• v.4 no.2
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• pp.59-68
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• 2003

The applicabilities and validities of two methodologies fur the prediction of THM (trihalomethane) formation in a water pipeline system were proposed and discussed. One is the multiple regression technique and the other is an artificial neural network technique. There are many factors which influence water quality, especially THMs formations in water pipeline systems. In this study, the prediction models of THM formation in water pipeline systems are developed based on the independent variables proposed by American Water Works Association(AWWA). Multiple linear/nonlinear regression models are estimated and three layer feed-forward artificial neural networks have been used to predict the THM formation in a water pipeline system. Input parameters of the models consist of organic compounds measured in water pipeline systems such as TOC, DOC and UV254. Also, the reaction time to each measuring site along pipeline is used as input parameter calculated by a hydraulic analysis. Using these variables as model parameters, four models are developed. And the predicted results from the four developed models are compared statistically to the measured THMs data set. It is shown that the artificial neural network approaches are much superior to the conventional regression approaches and that the developed models by neural network can be used more efficiently and reproduce more accurately the THMs formation in water pipeline systems, than the conventional regression methods proposed by AWWA.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.6
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• pp.769-775
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• 2008

This study was on the relative net income (RNI) for 18,286 Iranian Holstein cows from 799 herds, with first freshening between 1991 and 2000. Two kinds of production system, which differed mainly in milk pricing system and feed cost, were considered. Four different models adopted from the literature were examined to find the optimum model. They differed by the cost of rearing and growth after first calving and they needed different amounts of economic data at the farm level. Results showed that four measures of RNI were highly correlated (>0.96) and could be used equally to measure lifetime profitability of cows. Therefore, in herds without a regular system for recording economic and management data, use of the simplest model is recommended. Multiple regression analysis revealed that RNI was affected by age at first freshening, milk yield and days of productive life (DPL), regardless of production system, and a similar breeding goal could be defined for the two systems. Multiple regression analysis of RNI showed that in order to obtain an unbiased estimate of economic value for DPL, the per day milk yield, not total lifetime milk yield, should be included in the regression model along with DPL. Regression analysis suggested that it is possible to predict RNI using information on age at first freshening along with the length of first lactation and per day milk yield with a coefficient of determination ranging from 0.44 to 0.47.