• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.6
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• pp.21-26
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• 2020

In this paper, we investigated the characteristics of SF-MPAA depend on the structures of radiators when they were embroidered for realizing embroidered SF-MPAA. As increasing pitches by decreasing numbers of grids in length-direction and width-direction of the embroidered radiator the antenna gain and resonance frequency were trendingly decreased. However the characteristics of antenna were affected very much by the pitch in width-direction but affected relatively less by the pitch in length-direction. Therefore it was beneficial to decrease number of grids in length-direction to decrease conductor ratio. SLL was affected by the combination of length-direction pitch and width-direction pitch. The conductor ratio of embroidered radiator was determined by the ratio of pitch to embroidered thread thickness. When the ratio was less than 5 the conductor ratio was decreased rapidly. But when the ratio was larger than 5 the conductor ratio was decreased slowly and saturated.

• Korean Journal of Materials Research
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• v.6 no.2
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• pp.133-137
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• 1996

본연구에서는 n-type 세라믹 초전도체인 Nd2-xCexCuO4상의 산소함량에 따른 \ulcorner기적저항의 변화를 고찰하고자 하였다. 일반적인 소결과 어닐링과정을 결쳐 제조된 Nd1.85Ce0.15CuO4-x 시편을 여러 온도와 산소분압의 분위기하에서 어닐링시킴으로써 산소의 함유량이 다른 시편들을 준비하였고 각각의 시편의 산소함량은 TGA(Thermogravimetric Analysis0에 의해 측정하였다. Nd1.85Ce0.15CuO4-x시편의 전기적 저항 측정은 표준 4-탐침방법을 이용하여 액체헬륨을 주입시켜 상온으로부터 4K까지 측정하였다. Nd1.85Ce0.15CuO4-x시편의 산소함량, 3.96$\leq$4-x$\leq$4.0의 범위에서 전기적저항을 측정한 결과 초전도특성이 나타나기 시작한 임계산소함량은 4-x=3.990이었고 이때의 임계온도 Tc=12K이었다. 또한 임계온도, Tc는 산소함량 4-x=3.96에서 24K로 측정되었다. 특이할 만한 현상은 CuO/Cu2O 열역학적 상전이가 일어나는 조건이 Nd1.85Ce0.15CuO4-x 시편의 초전도가 일어나는 임계와 일치하였다. 즉, Cu2O가 안정한 영역에서는 초전도특성이 나타났고 CuO가 안정한 영역에서는 초전도특성이 나타나지 않았다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.287-287
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• 2008

HTS-케이블은 구리도체 대신 고온초전도도체를 사용하여 저항이 0이 되는 초전도현상을 이용하여 대용량 전력수송이 가능한 전력케이블로서 대도시의 전력부하 집중문제를 해결할 수 있는 환경 친화적 전력케이블이다. 최근 고온초전도선재의 고임계전류밀도화 및 장척화에 힘입어 HTS-케이블의 실용화를 목표로 경제성이 있는 전력케이블을 개발하려는 움직임뿐만 아니라 실증시험 등 활발한 연구가 진행 중이다. 그러나 초전도전력케이블에서 발생되는 교류손실은 케이블의 효율을 저하시킬 뿐만 아니라 냉동기비용 증가로 인한 기존 케이블과의 가격경쟁에서 경제성을 저하시키는 주된 요인으로 작용하기 때문에 이의 상용화에 앞서 교류손실에 대한 정확한 규명이 되어야 하며 또한 실계통 투입 시 중요한 선로임피던스에 대한 정확한 규명도 필요하다. 본 논문에서는 실제 한전 주관으로 고창시험장에 설치된 배전급 22.9 kV, 100 m, 50 MVA급 3 상 HTS-케이블에 대한 통전특성을 규명하기 위하여 먼저 HTS-케이블의 DC 통전특성을 조사하였다. 또한 3상평형운전상태에서 AC 통전특성(인덕턴스 및 교류손실)을 실험적으로 조사하였으며 5m-케이블에서 측정된 결과와 비교 검토하였다.

• Korean Journal of Poultry Science
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• v.39 no.3
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• pp.195-205
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• 2012

The objective of this study was to evaluate the effects of different levels of dietary ME on growth performance and carcass characteristics in two different strains of broiler chicken. A total of one thousand, 1-day-old A strain and R strain male chicks were randomly assigned into 8 treatments in a $2{\times}4$ factorial arrangement. They were fed iso-nitrogenic (CP 21%) crumbled diets formulated to contain metabolizable energy (ME) 2,950 to 3,250 kcal/kg in increment of 100 kcal/kg in the starter phase (1 to 21d) and iso-nitrogenic (CP 19%) pelleted diets containing same ME levels as in the finishing phase (22 to 38d). The body weight (BW) gain of chicks fed the lower ME diets (2,950 or 3,050 kcal/kg) were higher than those of the higher ME groups. The dietary energy level showed significant effects on feed intake and feed conversion rate (FCR) from 1 to 38 days of age (p<0.05). With the increment of dietary energy, feed intake tended to be reduced, whereas FCR was improved in the two strains of broiler chickens. The lowest FCR was observed at 3,250 kcal/kg diet groups in both of the two strains from 1 to 38 days of age. Feed intake and BW gain during 38 days were significantly affected by the strain factor. Increasing dietary energy up to 3,250 kcal/kg had no effect on the relative weights of breast meat and abdominal fat. The dietary energy and strains showed significant effects on the dressing percentage. There were no significant differences in various blood profiles except for GPT activity.

• Food Science of Animal Resources
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• v.31 no.2
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• pp.257-265
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• 2011

The current study was conducted to compare the growth performance and physico-chemical characteristics of Hanwoo bulls and steers of different slaughtering ages. Thirty-six Hanwoo (average age, 13-mon) were allocated into either a bull or steer group (18 animals/group). Each group was sub-divided into 26-, 28-, and 30-mon-old age groups (six animals/group). Surgical castration was performed in the steer group immediately after the experimental groups were assigned. Growth performance of the animals, as well as carcass characteristics and fatty acid composition of M. longissimus dorsi were determined. Cold carcass weights increased as carcass slaughtering age increased in both Hanwoo bulls and steers (p<0.05). Backfat thickness was thickest (p<0.05) in 28-mon-old Hanwoo bulls and 30-mon-old steer, and the M. longissimus dorsi area was widest (p< 0.05) in 28-mon-old Hanwoo bulls and steers. Marbling score, cooking loss, and water holding capacity (WHC) were higher (p<0.05) in 30-mon-old Hanwoo bulls and steers as slaughtering age increased. The shear force value was highest in 30-mon-old Hanwoo bulls and 26-mon-old Hanwoo steers compared to that in other groups. The unsaturated fatty acid composition in M. longissimus dorsi was significantly (p<0.05) higher in 28- and 30-mon-old Hanwoo bulls and steers than that in other groups. The results suggest that castration, even at late stages of Hanwoo development, improved beef carcass quality grade, and that no difference in beef quality grade had occurred (marbling score and WHC) in 28- and 30-mon-old slaughtering age Hanwoo steers.

• Journal of Animal Science and Technology
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• v.44 no.5
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• pp.599-606
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• 2002

This study was carried out to determine the physico-chemical components and to examine it the consumers can tell the difference in eating quality of loins of Hanwoo with grade and sex. Loins of 36 carcasses were selected and their intramuscular fat, color, pH, water holding capacity, shear force, the amount of myoglobin and moisture content were measured. The result was that only intramuscular fat was significantly different with grades. In Pearson correlation coefficients among quality factors, moisture content increased significantly with the amount of myoglobin(0.514) and shear force(0.503) and decreased as intramuscular fat(－0.957) and water holding capacity(－0.491) increased. Also, content of intramuscular fat decreased as shear force(－0.565) increased. According to descriptive analysis, aroma and acceptability in the 2nd grade steer showed the highest score. Aroma, juiciness and tenderness may affect acceptability of cooked meat. Also, juiciness, tenderness and acceptability had a negative correlation with moisture content and the intramuscular fat did not affect tenderness directly.

• Food Science of Animal Resources
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• v.31 no.3
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• pp.451-459
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• 2011

We investigated melting points and sensory characteristics by adding rice bran and roasted soybean to the finishing diet of Hanwoo steers. Thirty-six Hanwoo steers (average age, 20.92 mon-old; average weight, 599.89 kg) were assigned to either Control, Treatment 1 (rice bran) or Treatment 2 (roasted soybean) groups (12 steers/group), considering body weight and age. Supplementation levels of rice bran and roasted soybean were determined to meet total 5% crude fat in the concentrates, and the experimental animals were fed for 314 d until they reached 31.2 mon old. No significant differences were found in the moisture and crude fat content among groups. Melting points of lipid extracted from M. longissimus dorsi, subcutaneous fat, and perirenal fats were 25.83-26.17, 17.26-18.53 and $32.40-33.15^{\circ}C$, respectively, resulting in remarkable differences depending on fat depots. Contents of free amino acids in M. longissimus dorsi related to sweet taste were 39.48 mg/100 g for Treatment 1, which was significantly (p<0.05) higher than those for Control (32.24 mg/100 g), whereas those related to bitter taste were 25.93 mg/100 g for Treatment 2, which was the lowest (p<0.05) among the groups. Fatty acid composition, such as $C_{14:0}$, $C_{16:0}$, $C_{16:1}$, $C_{18:0}$, and $C_{18:1}$, in M. longissimus dorsi was not different among the groups. Results of a panel test on M. longissimus dorsi showed that Treatment 1 scored the highest (p<0.05) in juiciness, and both Treatments 1 and 2 scored higher (p< 0.05) in overall palatability than the Control group. $C_{18:1}$ showed a positive (+) relationship with tenderness (r = 0.650; p<0.05), and $C_{18:0}$ with flavor (0.698; p<0.05). The results suggest that rice bran and roasted soybean are beneficial for improving M. longissimus dorsi sensory characteristics, whereas no significant differences were found in the physico-chemical characteristics among the groups.

• Food Science of Animal Resources
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• v.32 no.2
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• pp.228-233
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• 2012

This study was conducted to determine the effects of stevia (Stevia rebaudiana bertoni) and charcoal supplementation on growth performance, immune response and carcass characteristics of finishing pigs. A total of 420 pigs (LYD) were randomly allocated into 7 treatments with 3 replications. Dietary treatments were 1) T1 (basal diet), 2) T2 (basal diet+0.3% stevia), 3) T3 (basal diet+0.6% stevia), 4) T4 (basal diet+0.3% charcoal), 5) T5 (basal diet+0.6% charcoal), 6) T6 (basal diet+0.3% stevia+0.3% charcoal) and 7) T7 (basal diet+0.6% stevia+0.6% charcoal). During the experimental period, average daily gain (ADG) was higher in T2 and T6 groups than the other treatments (p<0.05). Feed conversion ratio (FCR) was higher in T6 group compared to the others (p<0.05). There were no significant differences in total cholesterol level and glutamic pyruvic transaminase (GPT) activity of blood among treatments. In glutamic oxaloacetic transaminase (GOT) activity, T3, T5, T6 and T7 groups showed lower values (p<0.05) compared to T1. Insulin-like growth factor-1 concentration was higher in T2 and T6 groups than the others (p<0.05), but there were no significant differences in immunoglobulin G, lymphocyte, eosinophil, basophil and atypical lymph levels among treatments. In neutrophil, T6 showed higher level compared to the others (p<0.05). In the carcass characteristics, T6 showed higher level of a carcass grade compared to the other treatments. However, carcass length did not show any significant difference among treatments. As a result, dietary supplementation of 0.3% stevia and 0.3% charcoal showed higher ADG, higher FCR and better immune response resulting in better growth performance and carcass characteristics of finishing pigs.

• Food Science of Animal Resources
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• v.29 no.2
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• pp.188-193
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• 2009

This study was conducted to determine the effect of mugwort powder on meat composition and sensory characteristics in finishing gilts $(LY{\times}D)$. Twenty pigs (75kg) were randomly allotted to four treatments. Mugwort powder was added to final concentrations of 0(C), 0.5(T1), 1.0(T2), and 1.5%(T3) in the basal diet. Pigs were fed with the specified diet for 50 days. Carcass characteristics and cooking loss were not significantly affected by mugwort powder supplementation. The WHC and cooking loss of T2 and T3 were not significantly different than the control. However, the pH values for meat from gilts fed the T1 and T3 diets were significantly lower than the control (p<0.05). Shear force values of fresh meat were highest with the T3 diet (p<0.05), while the shear force values of cooked meat were significantly lower than the control with the T2 and T3 diets. Texture values of hardness, brittleness, gumminess, chewiness, and adhesiveness were significantly higher with the T3 diet (p<0.05), however values for cohesiveness and springiness were not significantly affected by mugwort powder supplementation. These results indicate that the feeding of mugwort powder improves the shear force of cooked meat from gilts fed the T3 diet, however the carcass, WHC and cooking loss characteristics in gilts are not affected by mugwort powder supplementation.

• Food Science of Animal Resources
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• v.23 no.2
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• pp.109-114
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• 2003

This study was conducted to investigate the effect of sarcomere length, carcass and quality traits on tenderness of Hanwoo beef at 24 hr postmortem. Immediately after slaughter, a total number of 30 carcasses(Hanwoo bull) selected, and sarcomere length was determined during rigor development(1, 3, 6, 12 and 24 hr). Tenderness group of longissimus dorsi muscle classified into tender group($\leq$7.5 kg/$\textrm{cm}^2$, n=9), or tough group($\geq$9.0 kg/$\textrm{cm}^2$, n=9) by shear force value at 24 hr postmortem, and estimated carcass traits, meat color, connective tissue and sensory property at 24 hr postmortem. Results showed that tender group had heavier carcass weight, thicker back fat, higher marbling score, lighter meat color, more white fat color and lower texture score(p<0.05). The change of sarcomere length was linearly decreased(p<0.05) from 3 hr postmortem, and the sarcomere length of tender group was significantly(p<0.05) longer than that of tough group at 3, 6 and 24 hr postmortem. The tender group showed significantly lower(p<0.05) shear force value of intramuscular connective tissue(IMCT), better(p<0.05) tenderness and overall acceptability compared to the tough group. Results indicated that tenderness of beef longissimus dorsi muscle could be improved by thicker back fat, higher marbling score and lower texture score, and predicted by sarcomere length of pre-rigor(3 and 6 hr postmortem). Also, the tenderness of beef longissimus dorsi muscle could be closely related to shear force value of IMCT, compared to total collagen and soluble collagen content in the same age.