• 한국통신학회논문지
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• 제24권9B호
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• pp.1676-1682
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• 1999

본 논문에서는 마이크로스트립 패치 안테나를 이중 원형 배열하였다. 부엽준위를 최소화하기 위하여 내원의 반경은 0.7 $\lambda$0, 외원의 반경은 1.45$\lambda$0로 하여, 내원과 외원에 각각 8개의 소자를 $45^{\circ}$간격으로 배열하였으며, 병렬 급전방식을 사용하여 각 안테나 소자에 도일한 전력과 위상을 공급하였다. 측정결과 설계 제작된 안테나의 복사특성은 이론치에 거의 근접하였으며, 반사손실은 11.75[GHz]에서 -14.5[dB]이며, 주엽을 0[dB]로 할 때, 첫 번째 부엽의 크기는 -18[dB], 두 번째 부엽의 크기는 -26[dB]의 특성을 보였다.

• 한국축산식품학회지
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• 제39권1호
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• pp.23-34
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• 2019

Fat reduction in the formulation of cheese emulsion causes problems in its flowability and functional characteristics during spray-dried cheese powder production. In order to eliminate these problems, the potential of using microparticulated whey protein (MWP) in cheese emulsions was examined in this study. Reduced-fat white-brined cheese emulsions (RF) with different dry-matters (DM) (15%, 20%, and 25% excluding emulsifying salt) were produced using various MWP concentrations (0%-20% based on cheese DM of emulsion). Their key characteristics were compared to full-fat cheese emulsion (FF). MWP addition had no influence on prevention of the phase separation observed in the instable group (RF 15). The most notable effect of using MWP was a reduction in apparent viscosity of RF which significantly increased by fat reduction. Moreover, increasing the amount of MWP led to a decrease in the values of consistency index and an increase in the values of flow behavior index. On the other hand, using high amounts of MWP made the emulsion more liquid-like compared to full-fat counterpart. MWP utilization also resulted in similar lightness and yellowness parameters in RF as their full-fat counterparts. MWP in RF increased glossiness and flowability scores, while decreased mouth coating scores in sensory analyses. Fat reduction caused a more compact network, while a porous structure similar to FF was observed with MWP addition to RF. In conclusion, MWP showed a good potential for formulation of reduced-fat cheese emulsions with rheological and sensorial characteristics suitable to be used as the feeding liquid in the spray drying process.

• 한국정보기술학회논문지
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• 제16권11호
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• pp.77-84
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• 2018

본 논문에서는 T-junction 전력 분배기를 이용한 원형 편파 마이크로스트립 패치 안테나를 제안하였다. 제안된 안테나의 동작 주파수는 2.4GHz의 ISM 대역이며, 패치 안테나의 두 가장자리에 $90^{\circ}$의 위상차를 급전하여 원형 편파를 유도하였다. 안테나의 구조는 일반적인 패치 안테나와 T-junction 전력 분배기로 구성된다. 안테나의 최적화를 위해 반사계수, 축비, 방사패턴 등이 분석된다. 안테나의 임피던스 대역폭은 2.39~2.43GHz 대역에서 40MHz의 대역폭이 관찰되었으며, 축비 대역폭은 2.398~2.410GHz 대역에서 약 12MHz의 대역폭이 관찰되었다. 안테나의 방사패턴은 우회전 원형 편파로 동작하였다. 또한 안테나의 이득은 XZ 및 YZ-평면에서 각각 2.04, 3.4㏈ic가 관찰되었다.

• 농업과학연구
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• 제48권2호
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• pp.265-272
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• 2021

A total of fourteen primiparous sows' (Landrace × Yorkshire) were used to determine the effects of two patterns of feed intake during early gestation on the growth performance and litter characteristics in sows. Daily feed intake from day 5 to 112 of gestation for parity 1 sows was 2.2 kg·d^-1 of feed offered with the exception of seven sows who were offered 3.2 kg·d^-1 from day 90 to 108 of gestation (TRT A) or 2.5 kg·d^-1 (d 5 - 60) and 2 kg·d^-1 (d 60 - 90) of feed with the exception of seven sows who were offered 3.5 kg·d^-1 from day 90 to 108 of gestation (TRT B). The different feed intake patterns in early gestation did not have a significant effect on body weight, backfat thickness, or body condition score during, before, and after farrowing (p > 0.05) respectively. However, initial to d 60, backfat thickness difference was significantly improved by TRT B patterns of feed intake during early gestation. In addition, during the overall experiment, average daily feed intake was significantly enhanced for sows in the dietary TRT B group feed intake pattern (p = 0.0001). The fecal score during day 90 was significantly reduced (p = 0.0132) in sows fed with TRT B feed intake pattern. Litter size, litter survival rate, and initial weight showed no significant differences with different feed efficiency of gestating sows. In summary, the results indicate that the 2.5 kg·d^-1 gestation intake pattern allowed gestating sows to obtain optimal performance.

• 농업과학연구
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• 제48권1호
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• pp.133-140
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• 2021

The aim of this study was to evaluate the growth performance between two different crossbred strains of Korean native chickens denoted as 1A and 2A compared to white semi broilers and Ross (RR) from hatching to 40 days. In total, 576 one-day-old chicks were allocated in a completely randomized design to give 18 replicate cages each (eight chicks per cage). The two-phase feeding program consisted of the starter (day 1 - 21: Crude protein [CP] 20% and metabolizable energy [ME], 3,050 kcal·kg^-1) and the grower (day 22 - 40: CP 18%, 3,100 kcal·kg^-1). The results revealed that 1A and 2A had a lower (p < 0.05) body weight (BW) from day 1 to day 40 compared with the other groups. A lower (p < 0.05) average daily gain (ADG) was observed in 1A and 2A during the entire period when compared with the other groups. The 1A and 2A groups had the minimum (p < 0.05) average daily feed intake (ADFI) compared with the other groups for the whole period. The RR had an improved (p < 0.05) FCR compared with the other groups during the whole period. The 1A and 2A groups were observed to have the lowest (p < 0.05) shank length compared with the other groups during the entire period.

• 공업화학
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• 제33권4호
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• pp.335-342
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• 2022

화석연료 사용 비중이 큰 농업분야에서는 최근 불안한 국제정제와 맞물린 에너지 가격 상승과 활발한 스마트팜 보급으로 전력사용량까지 증가하는 에너지 사용 패턴 변화로 새로운 국면을 맞고 있다. 따라서 친환경 분산형 전원으로 연료전지를 이용하며, 바이오매스를 직접 연료로 사용할 수 있는 연료전지 열병합발전 시스템은 농가에 열 및 전기에너지를 동시에 공급할 수 있는 효과적인 에너지시스템으로 인식되고 있다. 본 총설 논문에서는 바이오매스, 특히 농업부산물을 연료로 활용하기 위한 연료전지 기반의 열병합발전 시스템에 대한 공정 구성과 기술적 동향을 제시하고, 통합 연계공정 설계 시 고려해야 할 부분들을 논의하고자 한다.

• Animal Bioscience
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• 제36권5호
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• pp.776-784
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• 2023

Objective: This experiment was conducted to evaluate the inclusion of dietary nontoxic sulfur (NTS) on growth performance, immune response, sulfur amino acid composition and meat characteristics in growing-finishing pigs. Methods: A total of 140 crossbred pigs ([Yorkshire×Landrace]×Duroc) with an average body weight of 34.73±0.66 kg were used for the 12-week feeding trial. Experimental pigs were allotted to one of 5 treatments in 4 replicates of 7 pigs per pen in a randomized complete block (RCB) design. The experimental treatments were as follows (0%, 0.1%, 0.2%, and 0.4% NTS levels): i) Control, corn soybean meal (SBM)-based diet; ii) NTS 0.1, basal diet + NTS 0.1%; iii) NTS 0.2, basal diet + NTS 0.2%; iv) NTS 0.4, basal diet + NTS 0.4%. Results: Body weight increased linearly as dietary NTS levels increased up to 0.2% (linear; p = 0.04) in the early finishing phase (9 weeks). During the whole experimental period, body weight and average daily gain linearly increased as the dietary NTS level increased in the diet (linear; both p = 0.01), but quadratic responses in body weight and average daily gain were observed with the addition of NTS 0.4% (quadratic, both p = 0.01). In the late finishing period, the IgG concentration increased linearly (linear; p = 0.01) as the dietary NTS level increased up to 4%. In the finishing period, a linear response was observed as a dietary NTS level was added (linear; p = 0.03), and supplementation with 0.2% NTS resulted in a higher methionine content than the other treatments (quadratic; p = 0.01). NST 0.2% had a lower value of thiobarbituric acid reactive substances (quadratic; p = 0.01). Conclusion: Consequently, supplementation with dietary NTS up to 0.2% could improve growth performance, amino acid composition in hair and meat antioxidation capacity.

• Animal Bioscience
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• 제36권7호
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• pp.1059-1066
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• 2023

Objective: Present study was designed to evaluate the efficacy of Acacia nilotica bark extract as an alternative to antibiotic growth promoters in broilers. Methods: Six hundred, day-old broiler chicks were randomly divided into six groups (NC, without any supplementation; AB, NC+Zinc Bacitracin; PB, NC+Safmannan; ANBE1, NC+A. nilotica bark extract 0.1%; ANBE3, NC+A. nilotica bark extract 0.3%; ANBE5, NC+A. nilotica bark extract 0.5%), with ten replicates per group (10 chicks/replicate) and feeding trial was lasted for 35 days. Results: Results showed that weight gain (1,296.63 g) and feed conversion ratio (FCR, 1.59) of AB was better than NC, during the finisher phase. Overall FCR of AB (1.53), PB (1.54), and ANBE5 (1.54) was significantly (p<0.05) better than NC. From carcass parameters relative weight of wing and heart were highest in ANBE3 (2.5% and 1.51%, respectively). Significantly (p<0.05) highest blood glucose level was observed in NC (264.5 mg/dL) and highest albumin concentration was found in AB (1.46 mg/dL). In addition, antibody titer levels against ND and IBD were higher in ANBE5 than NC, while higher relative weight of bursa was observed in ANBE3 than NC. The villus height to crypt depth ratio in all experimental groups was better than NC. Conclusion: Acacia nilotica bark extract could be a suitable alternative to antibiotic growth promoters to support the growth in broilers.

• Nuclear Engineering and Technology
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• 제54권11호
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• pp.4329-4337
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• 2022

Jet impinging device is designed for decay heat removal on horizontal fuel rods in a low temperature heating reactor. An experimental system with a fuel rod simulator is established and experiments are performed to evaluate water film covering capacity, within 0.0287-0.0444 kg/ms mass flow rate, 0-164.1 kW/m² heating flux and 13.8-91.4℃ feeding water temperature. An effective method to obtain the film coverage rate by infrared equipment is proposed. Water film flowing patterns are recoded and the film coverage rates at different circumference angles are measured. It is found the film coverage rate decreases with heating flux during single-phase convection, while increases after onset of nucleate boiling. Besides, film coverage rate is found affected by Marangoni effect and film accelerating effect, and surface wetting is significantly facilitated by bubble behavior. Based on the observed phenomenon and physical mechanism, dry-out depth and initial dry-out rate are proposed to evaluate film covering potential on a heating surface. A model to predict film coverage rate is proposed based on the data. The findings would have reliable guide and important implications for further evaluation and design of decay heat removal system of new reactors, and could be helpful for passive containment cooling research.

• Journal of Animal Science and Technology
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• 제66권1호
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• pp.93-102
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• 2024

This study investigated the effect of dietary supplementation with phytase on growth performance, fecal excretion, and compost nutrition on broilers fed available phosphorus (avP)- and calcium (Ca)-deficient diets. A total of 750 one-day-old broiler chicks were randomly divided into five dietary groups having ten replications in a floor house. Diets of the groups were formulated with positive control (PC), negative control (NC; low avP and Ca), and NC supplemented with phytase levels; 500 (NC500), 1,000 (NC1000), and 1,500 FTU/kg (NC1500). A three-phase feeding program was used in the trial. Average daily gain (ADG) and average daily feed intake (ADFI) in the groups fed diets supplemented with phytase were significantly (p < 0.05) higher than those fed NC and the increase was equivalent to those fed PC. Serum levels of Ca and phosphorus (P) were higher (p < 0.05) in broilers fed NC1000 and NC1500 than in those fed NC. Interleukin (IL) level was the lowest in the group fed NC. Plasma myo-inositol (INS) concentrations in the NC1500 group were higher (p < 0.05) than PC, NC, and NC500 groups. Crude protein (CP) excretion was notably (p < 0.05) lower in the NC1500 group than in PC and NC groups. A lower (p < 0.05) concentration of P₂O₅ was observed in compost from the group fed NC1500 than the groups fed PC and NC. Accordingly, we suggest that phytase supplementation in lower avP and Ca levels of broiler diet can improve their productive performance and reduce environmental pollution.