• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.2
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• pp.18-25
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• 1994

In this papaer, the input impedance of the rectangular microstrip patch antennas with the multilayered structure is analysed by using the moment method technique in the spectral domain. The analysis is carried out for two different feeding structures : directfeeding structure and electromagnetic-feeding structure. In order to obtain the accurate input impedance, the current distribution on the microstrip feed line is modeled by the quasi-TEM travelling wave and the PWS(piecewise sinusoidal) mode. The input impedances of the designed microstrip antennas are measured and compared with the calculation. which shows a good agreement.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.11-15
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• 2002

This paper presents the thermal characteristic analysis of a high-speed HMC with spindle speed of 50,000rpm. The spindle is supported by two radial and axial magnetic bearings. and the built-in motor is located between the axial and rear radial magnetic bearings. The X-axis and Y-axis feeding systems are composed of linear motor and linear motion guides, and the Z-axis feeding system is composed of servo-motor, ballscrew and linear motion guide. The thermal analysis model of high-speed HMC is constructed by the finite element method, and the thermal characteristics in the design stage are estimated based on the temperature distribution and thermal deformation under the conditions related to the heat generation of built-in motor, magnetic bearings, linear motors, servo-motor, ballscrew, and so on.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.4
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• pp.7-14
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• 2003

Recently, LPG has been considered as more environmental friendly fuel than liquid fuels for vehicles. However because LPLi engine has the strong point that not only increases the volumetric efficiency and cold startability, but also decreases unburned hydrocarbon exhaust emission in warm-up condition, much attention has moved to development of the Liquid Phase LPG injection (LPLi) system from the mixer type LPG engine. To reduce exhaust NOx, this study investigated the effect of EGR with LPLi engine and determined optimized EGR feeding position and distribution. In addition, engine stability, performance, and exhaust emission level were evaluated.

• Korean Journal of Poultry Science
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• v.15 no.2
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• pp.73-79
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• 1988

In order to study the effects of feeding time (08：00 and 14：00 hours) and frequency (once a day, twice a day and once every other day) on the performances of broiler breeder hens, two experiments were conducted with 1, 248 hens of Maniker strain during 24－2 weeks (Experiment 1) and 42－60 weeks (Experiment 2) of age. The results obtained are summarized as follows ： 1. No significant differences were observed in hen－day egg production and feed conversion rate between feeding times or among feeding frequencies through the entire experimental period. 2. Mean egg weight during the age of 24－42 weeks was significantly increased by feeding in the afternoon (p＜0.01). But it was not significantly affected by feeding time or frequency during 42－60 weeks of age. 3. Fertility and hatchability of eggs at 36 weeks and 60 weeks of age were not significantly different among treatments. 4. By feeding in the afternoon egg breaking strength at 60 weeks of age was significantly improved (p＜0.05), but not at 36 weeks of age. 5. In diurnal distribution of egg production, hens fed in the afternoon produced more eggs in the afternoon than hens fed during the morning (p＜0.01).

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.1958-1964
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• 2016

AC railway feeding system use single phase to supply power to the railway vehicles. And the system use the rail track as a return current path, so that current flows in the rail. In this situation inductive interference on communication system and unsafe environment can appear on railway system. Therefore knowing the current distribution of catenary system and analysing the return current is required. In this study detail return current distribution was analyzed by modeling the catenary system as 4-conductors group. The distribution characteristics and trends of return current were studied by using the PSCAD/EMTDC and FDTD method that based on Maxwell equation was used to calculate the induced voltage. Simulation code was made by MATLAB. Using this study result data, we can suggest the proper installation location of digital device and these data can be used for additional studies related to return current or induced voltage as a base data.

• Journal of Environmental Science International
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• v.31 no.2
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• pp.149-169
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• 2022

Hwapocheon stream is located in Gimhae-si, Gyeongsangnam-do, and a part was declared a protected wetland area in 2017. In 2020 and 2021, we investigated the community structure of benthic macroinvertebrates of the Hwapocheon stream to provide ecological information for the management of the wetland. As a result, 4 phyla, 6 classes, 20 orders, 51 families, 83 species, and 2,621 individuals of benthic macroinvertebrates were identified. The average indices of diversity, richness, and evenness were the highest in the midstream area, whereas the highest average index of dominance was observed upstream. Seven biological water quality evaluations based on the distribution of benthic macroinvertebrates showed that the Biological Monitoring Working Party was an extremely suitable method for environmental evaluation of the Hwapocheon stream. Regarding functional feeding groups, the number of species of predators and gathering-collectors was the highest, and considering habitual dwelling groups, the number of species of clingers and sprawlers was the highest. The species number of Odonata, Hemiptera, and Coleoptera increased toward the downstream area, whereas the community loss index was the highest upstream. We also investigated relative resistance and resilience based on the distribution of aquatic insects and found that community stability was the highest downstream, whereas the lowest upstream.

• Journal of the Korean Institute of Telematics and Electronics
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• v.11 no.4
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• pp.30-38
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• 1974

This paper presents a method, which finds the current distribution and input impedance at the arbitrary feeding point of bended linear antenna in arbitrary shape in accordance with the MOMENT method. Practically the method of analysis is applied to the sinusoidal-shaped antenna, and the results of the calculation of current distribution and input impedance consist with the theoretical values. The method can be extensively used for the analysis of any of type antenna problems.

• Journal of Food Hygiene and Safety
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• v.12 no.4
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• pp.346-353
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• 1997

This study was undertaken to find out distribution and contamination sources of hazardous microbes through microbial hazard analysis on the processing steps of surimi-based imitation crab (SBIC). As a results of ananlysis of 9 hazardous microbes for 16 raw materials and 8 processing steps, no Samonella spp. and Escherichia coli were detected in all samples. Level and distribution of hazardous microbes in mixed color were similar to those of surimi. Changes of aerobic plate counts (APC), psychrotropic bacteria, coliforms, Staphylococcus aureus and Vibrio parahaemolyticus showed similar trends at different processing steps. Thermotrophic bacteria and aerobic sporeformers were not detected until mixing step and feeding step, respectively and not reduced after cooking step. According to the comparison of APC at each step, it was suggested that surimi, workers and silent cutter at mixing step, and mixed color, workers and bundler at packaging step were the major contamination sources of bacteria.

• Journal of the korean society of oceanography
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• v.32 no.2
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• pp.85-92
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• 1997

Seasonality in abundance and egg production was investigated for Calanus sinicus in Asan Bay, Korea, and feeding effort was measured in the laboratory condition. Although abundances of this species in this bay showed only one Peak in spring, egg Production showed two peaks, spring and fall, in this bay. Potential of year-round egg Production was also found. Food availability judged by the particulate organic carbon (POC) concentration was usually more than enough in this bay. High egg Production in fall resulted in spring Peak in abundance. But high egg Production in spring did not result in summer or fall Peak in abundance. Low abundances in summer and fall were believed to be the result of long range horizontal migration out to the central Part of the Yellow Sea. The highest average egg Production by the Population of this species was 16.3 eggs female-'day-'. Maximum e99 Production by an individual was 39.0 e99s female$^{-1}$ day$^{-1}$, which yielded 30.7% of specific egg Production rate in terms of body carbon content with the carbon contents of 44.44$^{\mu}$gC and 0.35 $^{\mu}$gC for individual adult female and egg, respectively. Clearance rate (F) measured in the laboratory condition decreased exponentially with the increase of food concentrations, as expected. The asymptote of F was 3.17 ml copepod$^{-1}$ h$^{-1}$. When this value and the minimum concentration of POC measured in the field were applied under the assumption of continuous feeding in the nature, the calculated gross efficient of egg production was 41.6% in case of average egg production of the population. Violation of the assumption of diurnal feeding rhythm and application of the minimum concentration of POC may offset the influence on calculation each other.

• Parasites, Hosts and Diseases
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• v.52 no.2
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• pp.169-175
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• 2014

There are 60 species of blood-feeding land leeches, 50 species belonging to the family Haemadipsidae and 10 species belonging to the family Xerobdellidae. Despite recent papers on the land leeches, their taxonomic identification is not fully understood, especially at a species level. In Korea, there have been no historical records of the terrestrial leeches, but recently an unrecorded blood-feeding land leech was discovered at Gageo-do (Island), Korea. Molecular analysis was used to identify the species of 29 leeches collected from Mt. Dock-Sil in Gageo-do. Conventional PCR was conducted using nuclear 18S rRNA and mitochondrial cytochrome c oxidase subunit 1 (CO1) genetic marker. The 18S rRNA sequences revealed that the leeches share 99.9% identity with Haemadipsa rjukjuana (inhabiting Taiwan), and the CO1 sequences revealed that the leeches are very close to H. rjukjuana (inhabiting Taiwan). The CO1 sequences were separated into 2 categories, 1 with 94.6% and the other with 94.3% similarity to the H. rjukjuana L00115A (inhabiting Taiwan). This new finding of the land leech is the first record in Korea. In addition, the north range of the distribution of the blood-feeding leech (Hirudiniformes: Haemadipisidae) should be reconsidered including Korea.