• 한국전자파학회논문지
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• 제22권2호
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• pp.140-147
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• 2011

본 논문에서는 차량 후면 유리에 여러 주파수 대역의 안테나를 집적화할 수 있는 유리접지를 이용한 안테나 급전 방법을 제안하였다. 유리접지가 가능하도록 동축 선로를 유리접지면에 직접 연결할 수 있는 어댑터를 설계하였으며, 차체 접지 방식과 반사 손실을 비교 분석하였다. Azimuth 방향에서 높은 복사 이득을 얻기 위해 유리 접지의 크기와 위치를 최적화 하였으며, 도출된 유리접지면을 이용하여 삼각 패치 형상의 WiBro 안테나를 상용세단의 후면 유리에 인쇄하고 반사 손실과 복사 패턴 성능을 측정하였다. 제안된 유리접지를 이용한 급전 방식은 차체 접지를 이용한 급전 방식과 유사한 반사 손실을 보이며, 2 dB 높은 azimuth 복사 이득이 나타내었다. 측정 결과, 제안된 유리접지면을 이용한 안테나 급전 방식을 이용하면 여러 주파수에서 동작하는 다양한 형태의 온-글래스 안테나를 후면 유리에 효과적으로 적용할 수 있음을 확인하였다.

• 전기학회논문지
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• 제62권4호
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• pp.577-583
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• 2013

We have analyzed influence of potential rise in negative bus, which caused by decrease of power feeding line insulation, upon protecting method of DC ground protection device which detecting potential rise between negative bus and ground in order to detect ground fault in the rubber wheel system. For this purpose, we proposed negative potential equation between negative bus and ground and calculated negative potential according to system condition changes by estimating power feeding line insulation changes in steel wheel system and rubber wheel system, and equalizing DC power feeding system when ground fault occurred. Also, in order to estimate negative potential of real system, we modeled the rubber wheel system, and simulated normal status, grounding fault occurrence and power feeding line insulation changes. In normal status, negative potential did not rise significantly regardless of vehicle operation. When ground fault occurred, negative potential rose up over 300V regardless of fault resistance. However, we also observed that negative potential rose when power feeding line insulation dropped down under $1M{\Omega}$. In conclusion, our result shows that in case of rubber wheel system unlike steel wheel system, relay will be prevented maloperation and insulation status observation can be ensured when ground over voltage relay will be set 200V ~ 300V.

• Asian-Australasian Journal of Animal Sciences
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• 제21권2호
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• pp.204-213
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• 2008

Four ruminally cannulated Holstein cows averaging 43 days in milk (DIM) were used in a $4{\times}4$ Latin square to determine the effect of feeding extruded soybean, ground canola seed and whole cottonseed on ruminal fermentation and milk fatty acid profile. One hundred and twenty lactating Holstein cows, 58 (${\pm}31$) DIM, were assigned to four treatments in a completely randomized block design to study the effects of the three types of oilseeds on production parameters and milk fatty acid profile. The four diets were a control diet (CON) and three diets in which 10% extruded soybean (ESB), 5% ground canola seed (GCS) and 10% whole cottonseed (WCS) were included, respectively. Diets consisted of concentrate mix, corn silage and Chinese wild rye and were balanced to similar concentrations of CP, NDF and ADF. Ruminal fermentation results showed that ruminal fermentation parameters, dry matter intake and milk yield were not significantly affected by treatments. However, compared with the control, feeding cows with the three oilseed diets reduced C14:0 and C16:0 and elevated C18:0 and C18:1 concentrations in milk, and feeding ESB increased C18:2 and cis9, trans11 conjugated linoleic acid (CLA). Production results showed that feeding ESB tended to increase actual milk yield (30.85 kg/d vs. 29.29 kg/d) and significantly decreased milk fat percentage (3.53% vs. 4.06%) compared with CON. Milk protein (3.41%) and solid non-fat (13.27%) from cows fed WCS were significantly higher than from cows fed CON (3.24% and 12.63%, respectively). Milk urea N concentrations from cows fed the ESB (164.12 mg/L) and GCS (169.91 mg/L) were higher than cows fed CON (132.31 mg/L). However, intake of DM, 4% fat corrected milk, energy corrected milk, milk fat and protein yields, milk lactose percentage and yield, somatic cell count and body condition score were not affected by different treatments. The proportion of medium-chain fatty acid with 14 to 16 C units in milk was greatly decreased in cows fed ESB, GCS and WCS. Feeding ESB increased the concentration in milk of C18:1, C18:2, C18:3 and cis9, trans11-CLA content by 16.67%, 37.36%, 95.24%, 72.22%, respectively, feeding GCS improved C18:0 and C18:1 by 17.41% and 33.28%, respectively, and feeding WCS increased C18:0 by 31.01% compared with feeding CON. Both ruminal fermentation and production trial results indicated that supplementation of extruded soybean, ground canola seed and whole cottonseed could elevate the desirable poly- and monounsaturated fatty acid and decrease the medium chain fatty acid and saturated fatty acid content of milk fat without negative effects on ruminal fermentation and lactation performance.

• 유기물자원화
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• 제18권4호
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• pp.45-53
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• 2010

여러 가지 방법으로 전처리된 느타리 버섯 폐배지에 대한 줄지렁이 개체군의 섭식률 및 생장률을 조사하였다. 갓 발생한 버섯폐배지의 부숙기간을 달리하여 지렁이에게 급이하였을 경우, 20일 이상 부숙된 버섯 폐배지보다 10일 이하로 부숙된 버섯 폐배지에 대한 지렁이 개체군의 섭식량 및 생장률이 높았다. 분변토를 첨가한 버섯폐배지나 질소영양원으로서 요소비료를 첨가하여 부숙한 버섯폐배지는 지렁이 개체군의 섭식률과 생장률을 증대시키지 못하는 것으로 나타났다. 그러나 버섯폐배지를 분쇄하여 공급하였을 경우에는 섭식량 및 생장률이 증가하였다. 특히 분쇄된 버섯폐배지에 미강을 첨가하였을 경우에는 분쇄하지 않은 단순 버섯폐배지보다 생장률이 1.85배 증가하였다.

• Journal of Ecology and Environment
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• 제43권3호
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• pp.297-304
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• 2019

Background: The growing wild boar population has become a social issue and its feeding characteristics could affect the physical condition and the plant species composition in the South Korean forests. We aimed to reveal the preference of the wild boar on forest type and site condition as feeding grounds in two cool-temperate forested national parks, Odaesan and Seoraksan, in order to provide information to manage the growing population. Results: The 75 plots (53.6%) out of 140 plots were used as feeding grounds by the wild boar, implying a considerably large population. Especially, the observation frequency as feeding ground was the highest in Quercus forests (73.3%), and it was significantly more preferred than deciduous forest type (44.2%) and coniferous forest type (32.4%) (${\chi}^2=17.591$, p < 0.001). Significantly more and deeper pits were found in Quercus forests. Moreover, high elevation and gentle slope ridge were relatively preferred regardless of forest distribution. Conclusions: South Korean forests are growing qualitatively and quantitatively. Particularly, Quercus forest area has increased markedly, while coniferous forest area has decreased. Since the Quercus forest provides rich food sources for the wild boar, the enlargement of this forest type is expected to increase the wild boar population. The forests located at high elevations have high species diversity, and it is expected that these forests will be greatly affected by the increase in the wild boar population as preferred feeding grounds.

• 한국전자파학회논문지
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• 제28권6호
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• pp.497-500
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• 2017

본 논문은 I-모양의 슬롯 섭동과 수직한 급전구조를 이용한 원형 편파 마이크로스트립 안테나를 제안하였다. 제안한 안테나는 대칭 및 수직한 급전구조와 접지면의 I-모양 슬롯 섭동이 구비된 방사체로 구성된다. 수직한 급전구조와 접지면의 슬롯 섭동 구조로 인하여 90도 위상 차이를 가지는 모드가 형성되어 좌회전 편파(left-handed circular polarization)가 발생한다. 제작한 안테나는 위성통신시스템을 위한 S-대역 2.2 GHz로 설계하였으며, 측정 결과 91 MHz의 -10 dB 대역폭이 관찰되었다. 대역폭 내에서 측정된 안테나의 이득, 원거리 방사패턴 그리고 축비는 이론적인 실험 결과와 잘 일치함을 확인하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권12호
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• pp.1758-1762
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• 2001

Equal number of red jungle fowl (JF) and commercial broiler chickens (CB), raised in battery cages, were provided a single complete diet (control) or a choice of a complete diet, ground corn and ground soybean from 21 to 56 days of age. There were significant genotype ${\times}$ feeding regimen interactions for several traits measured suggesting CB and JF responded differently to the two feeding regimens. The single fed CB had better growth and feed conversion ratios (FCR) than those under choice feeding. However, the body weight and FCR of JF were not affected by feeding regimen. While the single fed and choice-fed JF consumed similar amount of protein during days 21 to 55, the protein intake of the choice-fed CB was lower than the control. From days 21 to 55, irrespective of genotype, choice-fed chicks consumed less energy than their single fed counterparts. Regardless of genotype, the trend in the proportion of each feed consumed was similar with complete diet>corn>soybean. In conclusion, while choice-fed JF were capable to select nutrient necessary for maximum growth, choice feeding was detrimental to growth and feed conversion ratio in CB.

• 항공우주기술
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• 제2권1호
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• pp.117-123
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• 2003

본 논문에서는 3단형 과학로켓 KSR-III의 발사에 사용된 지상 추진제 공급설비를 소개하고 설비의 구성, 개발현황에 대하여 기술하고자 한다. 발사장 내의 추진제 공급설비는 KSR-III의 비행시험을 위해 발사 시나리오에 따라 발사체에 추진제 및 가압제를 각 요구조건에 부합하게 공급하는 설비이다. 구현된 공급설비는 크게 추진제 및 가압제 저장/공급 설비와 제어계측 설비로 구성되며 각종 입증시험과 연계시험을 통하여 그 성능 검증을 마친 후 KSR-III 비행시험에 성공적으로 사용되었다.

• Journal of electromagnetic engineering and science
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• 제18권4호
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• pp.261-266
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• 2018

This paper reports on the proposed design of a low profile broadband array antenna for home repeater applications. The proposed antenna consists of $1{\times}4$ patch elements and two ground planes, one of which is slitted. By using the gap feeding method, the impedance matching of the antenna is improved by a multi-resonance phenomenon. The proposed antenna provides a wide -10 dB reflection coefficient bandwidth simultaneously covering the Global System for Mobile communications (GSM-1800), Personal Communications Service (PCS), and the Universal Mobile Telecommunication System (UMTS) bands (1.67-2.32 GHz). In order to reduce the mutual coupling between adjacent patch elements, slits are embedded in the ground plane. An isolation level of -20 dB is realized over the entire operating frequency band.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.344-351
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• 1999

The safe operation of electro railways is greatly dependant on its protective systems. The system so-called Fault Protection Wire(FW) is now widely adapted to protect in AT feeding systems. It is connected between the feeder and trolley circuit to return the fault current to autotransfonmers at substation. This paper computed the distribution of fault currents at FW in the system and also evaluated the safety from electric shock when ground fault or flashover occur in the feeding system. The results show FW is useful to protect power supply network from fault in electric railways