• 한국가축번식학회지
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• 제10권1호
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• pp.49-57
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• 1986

Studies were conducted to investigate the relationship between hormone leveles and nutritional levels for improving performance of Cheju native cattle. In June 1984 a trial was initiated using 8 Cheju native calves after weaning, fed at two su, pp.ementary feeding levels (NRC 100% and 70%). The body weight, breedng performence, change in progesterone level during pregnancy and estrus cycle were evaluated. Mean body weight at 6 months of age was 155kg when fed 100% NRC ration but it was only 137kg when heifers received the 70% NRC ration. At 10, 15 and 20 months of age the body weight was 66, 160 and 115kg, respectively, showing that heifers fed the standard ration gained weight rapidly (P<0.01). Average size of the lefe ovary in the standard group was 2.1${\times}$1.6cm and right ovary was 2.6${\times}$1.8cm. However in the restricted feeding group the ovaries were found to be smaller. Diameter of graffian follicles showed a similar tendency to ovarian size in the two groups. The first oestrus in the standard feeding group a, pp.ared at 14.6 months when body weight was 265kg. Age at first calving was on average 28.9 months at a body weight of 436kg. On the other hand when heifers were fed the restricted ration the first oestrus a, pp.ared at 23.0 months at a body weight of 250kg. Average age at first calving was 38.9 months which was 10 months later than the average in the standard feeding group (P<0.01). In standard feeding group the progesterone level was 2.0ng/ml at two weeks after pregnancy and gradully increased up to 4 weeks and peaked at 18 weeks. This peak (6.4-6.5ng/ml) was maintained up to 24 weeks when progesterone level decreased until it reached 2.1ng/ml at the end of pregnancy. In the restricted group progesterone level up to 16 weeks followed a similar pattern to the standard group but there was a tendency in the restricted group to have lower progesterone levels(P<0.01). The standard and srstricted groups showed similar patterns of progesterone concentration during the oestrus cylce. There were no statistically significant differences in progesterone levels between standard and restricted groups but there was variation between induvidual animals.

• Asian-Australasian Journal of Animal Sciences
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• 제19권4호
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• pp.593-600
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• 2006

The effects of breed and sex on individual growth performance and feeding behaviour were studied between 45 and 90 kg BW in two replicates of forty group-housed pigs. The first and the second replicates were carried out during the warm season (i.e. between February and April 2003) and during the hot season (i.e. between August and October 2003), respectively. During the warm season, ambient temperature and relative humidity averaged $25.3^{\circ}C$ and 86.0%. The corresponding values for the hot season were $27.9^{\circ}C$ and 83.6%. The pigs were grouped in pens of 10 animals on the basis of breed (Creole or Large White) and sex (gilt or castrated male) and given ad libitum access to a grower diet (9.0 MJ/kg net energy and 158 g/kg crude protein) via feed intake recording equipment (Acema 48). An ear-tag transponder was inserted into each pig and this allowed the time, duration, and size of individual visits to be recorded. The growth performance and feeding pattern were significantly affected by breed, sex, and season. The Creole pigs (CR) had a lower average daily gain (ADG) (642 vs. 861 g/d, p<0.01) and carcass lean content ($LC_{90kg}$) (35.4 vs. 54.5%; p<0.01) and a higher backfat thickness at 90 kg BW ($BT_{90kg}$) (23.4 vs. 10.4 mm; p<0.01) than Large White pigs (LW) whereas the average daily feed intake (ADFI) was not affected by breed (2.34 vs. 2.22 kg/d, respectively for CR and LW pigs; p>0.10). Consequently, the food:gain ratio was higher in CR than in LW (3.65 vs. 2.58; p<0.01). CR had less frequent meals but ate more feed per meal than LW (5.9 vs. 8.8 meals/d and 431 vs. 279 g/meal; p<0.01). The rate of feed intake was lower (27.6 vs. 33.9 g/min; p<0.01) and the ingestion time per day and per meal were higher in CR than in LW (87.1 vs. 69.7 min/d and 15.8 vs. 8.4 min/meal; p<0.01). The ADFI and BT90 kg were higher (2.38 vs. 2.17 kg/d and 18.1 vs. 15.9 mm; p<0.05) and LC90 kg was lower (43.5 vs. 46.4%; p<0.01) in castrated males (CM) than in gilts (G) whereas ADG was not affected by sex (p = 0.12). The difference in lean content between CM and G was greater in CR than in LW. The ADFI and ADG were reduced during the hot season (2.18 vs.2.38 kg/d and 726 vs. 777 g/d, respectively; p<0.05) whereas feed conversion and carcass lean content were not affected by season (p>0.05). Average feeding time per meal and meal size decreased during the hot season (10.9 vs. 13.2 min/meal and 316 vs. 396 g/meal; p<0.01) whereas the rate of feed intake was not affected by season (p = 0.83). On average, 0.69 of total feed intake was consumed during the diurnal period. However, this partition of feed intake was significantly affected by breed, sex, and season. In conclusion, the breed, sex and season significantly affect performance and feeding pattern in growing pigs raised in a tropical climate. Moreover, the results obtained in the present study suggest that differences observed in BW composition between CR and LW are associated with difference in feeding behaviour, in particular, the short-term regulation of feed intake.

• Journal of Nutrition and Health
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• 제24권1호
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• pp.48-57
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• 1991

The longitudinal changes on human milk volume per day and lactational performance of Korean primiparae(n=9) and multiparae(n=6) from 0.5 month to 5 months after parturition have been studied by test-weighing method. The human milk volume per day tended to increase during lactation. The mean volume to the 3rd month of lactation was 643m1 for primiparae and 654m1 for multiparae, and it was 647 $\pm$ 182m1 for both of them. The mean volume to the 5th month of lactation was 648m1 for primiparae and 668m1 for multiparae, and it was 658$\pm$186$m\ell$ for both of them. The peak volume was observed at the 1st month of lactation in 8 women of 15 lactating women, that is, 53.3% . The high distributions of the individual mean volume to the 5th month were found 550~650$m\ell$(40.0% ) and 650~750$m\ell$(26.7% ). and 13 women of 15 lactating women(86.6% ) were observed below 750m1. The number of feeding per day was 7.7~9.3 to the 5th month and the mean volume per feeding was 65~101$m\ell$. While the former tended to decreased, the latter increased during lactation. The human milk volume was correlated with the peak volume. but not with maternal age. weight before delivery. maternal height and birth weight. As mentioned above, the human milk volume of Koreans was about 658$\pm$ 186$m\ell$ and 86.6% of it was below 750$m\ell$. So the human milk volume, referred to as 800$m\ell$ in recommended dietary allowances for Koreans might be estimated over real amount. It is necessary to study according to regions. socioeconomic levels. maternal nutritional status and the early stage of lactation.

• 한국전자통신학회논문지
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• 제17권6호
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• pp.1033-1038
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• 2022

본 논문에서는 3.5GHz 대역에 대해 측면 결합 선로(BCS:Broadside Coupled Striplines)에 의해 공급되는 프린트 다이폴 안테나의 설계 제작에 대해 연구하였다. 프린트 다이폴 안테나의 두 Arm(암)은 각각 기판의 양면에 있습니다. 1×2배열 안테나에 적용된 공급 균형 라인은 BCS입니다. 프린트 다이폴 안테나의 여러 파라미터 연구를 하였고, 시뮬레이션 결과는 최종 실험 데이터와 일치하였다. 실험 결과 원하는 주파수 대역에서 가장 넓은 대역폭을 나타내며 VSWR < 2.0:1 대해 28%의 대역폭을 보였다. 기존 프린트 다이폴 안테나의 단점인 협대역과 배열 시 급전선 특성을 개선할 수 있음을 알 수 있었다. 수평면 방사패턴은 전방향 특성을 보였고 최대 이득은 4.4dBi를 보였다.

• 한국전자파학회지:전자파기술
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• 제3권1호
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• pp.20-27
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• 1992

$\lambda$/2 다이폴 안테나 3개판 x,y,z축상에 서로 직교되도록 배열하여 각 소자의 수신 출력을 합성하므로써 등방성 패턴 안테나가 실현되었다. 각 소자는 H20MHz-895MHz익 서례 주파수 대역에서 임피먼스 정합플 양호하게 하고, 소자간의 상호 결합 효과를 최소로하기 위하여 슬리브 형태의 $\lambda$/2 다이폴 안테나를 사용하였다. 설계된 등방성 패턴 얀테나로 부터 복사된 충 전계의 세기는 원방계에서 각 촉상의 다이폴에 의해 발생 되는 Magnetic Vector Potential을 이용하여 계산하였다. 계산결과, 총 전계의 세기는 원점으포 부터의 거리에는 반비례하였고, 패턴상수 차이는 2.1dB이하이었다. 또한, x,y,z 축상에 배열된 안테나에서 수산된 합성전계의 편차는 2.8dB이하로 이론적 계산치와 O.7dB 정도의 차이가 있었다.

• 한국양식학회지
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• 제15권1호
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• pp.43-48
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• 2002

We investigated the gonadosomatic index (GSI), germ cell development, reproductive cycle of the Afriean lungfish Protorierus annecteus (Owen) by histological observations and morphometric data. Samples were collected from the river Orie and its flood of Nigeria, from January to December 2000. The fish is dioecious and oviparous. Monthly changes in the gonadosomatic index (GSI) showed a similar pattern to change in the mean oocyte diameter and the reproductive cycle. The reproductive period occurred from March to July-August; the spawning period was once a year between truly and August, and the main spawning occurred in August when active and voracious feeding occurred during the rainy season. In the resting (dormant) stage after spawning, fish stopped feeding and aestivated during the dry season from December to February. The reproductive cycle of the species can be divided into five successive stages, quiescent stage (March to April), developing/maturing stage (April to lune), ripe/spawning stage (July to August), post-spawning stage (September to November), and resting (dormant) stage (December to February).

• 한국군사과학기술학회지
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• 제11권6호
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• pp.135-141
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• 2008

본 논문에서는 다중 편파 및 3:1 이하의 대역폭을 갖는 광대역 혼 안테나 설계 기법을 제시하였다. 급전단은 다중 편파 및 광대역 구현을 위하여 4중 릿지(Quadruple Ridge) 형태의 도파관을 적용하였으며, 반구(Semi­sphere) 형태의 백 쇼(Back Short)를 갖는 캐비티 구조내에 쇼팅 바(Shorting Bar)를 삽입함으로써 반사손실을 최소화하였다. 안테나 개구면에서의 위상보정을 통해 안테나 범 패턴을 개선시키기 위하여 주름진 형태의 유전체 렌즈를 설계하였다. 설계 기법을 기반으로 제작된 얀테나의 측정결과를 제시함으로써 설계 방법의 타당성을 겸증하였다.

• Journal of Nutrition and Health
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• 제27권9호
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• pp.949-956
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• 1994

The effect of zinc deficiency on certain immunological parameters was investigated using intragastric tube feeding to obviate decreased food intake and altered eating pattern. Male, Fischer 344 rats were bilaterally adrenalectomized(ADX) or sham operated(SHAM). ADX rats received 0.9% NaCl in their drinking water and corticosterone injections at the dose of 1mg/kg of body weight three times per day. After recovery, one half of ADX and SHAM animals were tube-fed a purified, liquid diet containing either two ppm of zinc(zinc-deficient, force-fed ; ZDF) or 50ppm(zinc-replete, force-fed ; ZRF) for 19 days. They received identical amounts of diet based on the intake of ad libitum-fed, zinc-replete rats. Although they received identical amounts of food, ZDF rats grew at a slower rate compared to ZRF rats in both SHAM and ADX rats. Regardless of surgery, force-feeding rats the zinc-deficient diet resulted in a substantial decrease in serum zinc levels. The weights of the thymus, lymph node, and spleen were lower in SHAM-ZRF rats compared to SHAM-ARF rats. Marginal zinc deficiency caused lymphopenia in SHAM animals. However, these differences in lymphoid tissues and cells between SHAM-ZDF and SHAM-ZRF rats disappeared in ADX rats. These results indicate that the impaired growth of lymphoid tissues observed in zinc-deficient, sham-operated animals can be attributed to elevated serum corticosterone levels under the conditions of our experiments.

• 한국전자파학회논문지
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• 제14권8호
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• pp.878-883
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• 2003

본 논문에서는 평판형 마이크로스트립 공진기를 위한 선형 및 지수형 테이퍼 라인을 이용한 급전선 구조를 제안하였다. 제안된 테이퍼 급전선(Tapered Feedline: TFL)은 결합 효율 증가에 의해 공진기 설계시 발생하는 결합 손실과 임피던스 부정합의 문제를 해결하였다. 제안된 구조의 급전각에 따른 삽입 손실 및 대역폭 변화에 대한 특성이 평가되었으며, ${\lambda}_{g}$/2의 최적 급전선 길이가 제시되었다. 제안된 테이퍼 급전선 구조를 마이크로스트립 링 공진기/여파기와 패치 안테나에 적용하였으며, 공진기/여파기 구조에서는 약 7 dB의 삽입 손실 이득을 얻었으며, 패치 안테나에서는 우수한 정합 특성과 왜곡 없는 방사 패턴 등을 나타내었다.

• Journal of Magnetics
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• 제14권2호
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• pp.75-79
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• 2009

Nickel (Ni) and ferrite ($Fe_3O_4$, $NiFe_2O_4$) nanoparticles were synthesized by LGC using both wire feeding (WF) and micron powder feeding (MPF) systems. Phase evolution and magnetic properties were then investigated. The Ni nanopowder included magnetic-ordered phases. The LGC synthesis yielded spherical particles with large coercivity while the abnormal initial magnetization curve for Ni indicated a non-collinear magnetic structure between the core and surface layer of the particles. Since the XRD pattern cannot actually distinguish between magnetite ($Fe_3O_4$) and maghemite (${\gamma}-Fe_2O_3$) as they have a spinel type structure, the phase of the iron oxide in the samples was unveiled by $M{\ddot{o}}ssbauer$ spectroscopy. The synthesized Ni-ferrite consisted of single domain particles, including an unusual ionic state. The synthesized nanopowder bore an active surface due to the defects that affected abnormal magnetic properties.