• 대한기계학회논문집
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• 제19권10호
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• pp.2637-2646
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• 1995

Combustion instability in solid-propellant rocket motors depends on the balance between acoustic energy gains and losses of the system. The objective of this paper is to demonstrate the capability of the program which predicts the standard longitudinal stability using acoustic modes based on linear stability analysis and T-burner test results of propellants. Commercial ANSYS 5.0A program can be used to calculate the acoustic characteristic of a rocket motor. The linear stability prediction was compared with the static firing test results of rocket motors.

• 유공압시스템학회논문집
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• 제7권4호
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• pp.23-31
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• 2010

As the analysis and design technologies for electro-magnetic actuation has advanced over the years, proportional solenoid valve is gaining acceptance in wide range of industrial and commercial applications because of its superior characteristics over the conventional AOV or MOV, such as improved performance, reduced maintenance costs. This research deals with the position controller design of two-stage flow control solenoid valve. Investigation of steady-state characteristics and dynamic model identification for pilot disc is performed. Least square method to minimize the error magnitude of frequency response between the closed-loop and target system is applied to the design of PI-controller gains. From the experiments of step and frequency response, it is concluded that the controller meets the performance specification of target system, which verifies the usefulness of controller design method for proportional solenoid valve.

• 한국양식학회지
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• 제3권1호
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• pp.39-48
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• 1990

인공사료의 단백질 함량이 옐로우$\cdot$퍼치(Percidae)의 성장에 미치는 영향을 조사하였다. 단백질 함량 50, 40 및 $27\%$의 정제된 사료를 20주간 투여한 결과 사육초기에는 $50\%$ 및 $40\%$ 단백질 사료 투여군이 $27\%$ 사료투여군 보다 성장이 빨랐으나 10주 이후부터는 성장이나 사료 전환효율이 거의 동일하였고 3개 실험군 간에 통계적으로 유의성이 있는 차이를 찾아 볼 수 없었다. 옐로우$\cdot$퍼치의 치어(체중 약 6g)는 사육개시후 약 10주 이후 혹은 체중이 약 12g에 달했을 때부터는 단백질 요구량이 철저하게 감소하는 경향을 나타내어 $27\%$ 단백질 사료로서 정상적인 성장을 보여 주었다. 이는 자연계에서 매우 강한 육식성으로 고단백 식성 어류인 퍼치를 일반상업용 사료($50-56\%$ 단백질)보다 약 $23\%$ 이상의 단백질이 절감된 $27\%$ 단백질 사료로 실내에서 사육할 수 있음을 의미한다.

• Asian-Australasian Journal of Animal Sciences
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• 제14권12호
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• pp.1741-1746
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• 2001

An experiment was conducted at the experimental duck farm of Cantho University to determine the effects of feeding duckweed (Lemna minor) that completely replaced commercial protein supplements in diets for crossbred meat ducks. The experiment included five treatments, with four replicates and ten crossbred ducks per replicate (pen). The five diets were based on broken rice offered ad libitum, supplemented with either 27 (control, SB100), 19 (SB70), 15 (SB55), 12 (SB40) or zero (SB0) g/day of ground, roasted soya beans, with fresh duckweed supplied ad libitum, except for the control (SB0) treatment. A vitamin / mineral premix and salt were included in the control (SB100) diet, but not in the diets with duckweed. These diets were fed to growing crossbred meat ducks (Czechoslovak Cherry Valley hybrids) from 28 to 63 days of age, when two birds (one male and one female) per pen were slaughtered for carcass evaluation. Total daily intakes were 95, 108, 108, 105 and 107 g of dry matter (DM) (p<0.001) and daily live weight gains 26.1, 29.1, 28.3, 27.1 and 27.6 g (p<0.001) for the SB100, SB70, SB55, SB40 and SB0 diets, respectively. Corresponding feed conversion ratios (FCR, dry matter basis) were 3.63, 3.71, 3.82, 3.89 and 3.88 kg feed/kg gain, respectively. There were no significant differences in carcass yields, chest and thigh muscle weights, and internal organ weights between the ducks fed the control diet and those fed duckweed diets. Fresh duckweed can completely replace roasted soya beans and a vitamin-mineral premix in broken rice based diets for growing crossbred ducks without reduction in growth performance or carcass traits. If the duckweed is grown on farm, and managed and harvested by household labour, the saving over purchased protein supplements is up to 48%.

• 한국전자파학회논문지
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• 제16권12호
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• pp.1206-1212
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• 2005

본 논문에서는 전기 전류와 자기 전류를 동시에 생성하여 인식 음영 구역을 제거할 수 있는 새로운 형태의 RFID 태그 안테나를 설계하였다. 변형된 이중 T 매칭 네트워크를 이용하여 상용 태그 칩을 안테나에 공액 정합을 시켜, 848${\~}$926 MHz의 넓은 대역폭($S_{11}< -10 dB$)과 $90\%$ 이상의 높은 복사 효율을 얻었다. 제안한 안테나는 동작 주파수 부근에서 최대 이득과 최소 이득의 차이가 약 4 dB로 유사 등방성 복사 패턴을 가지며, 상용 태그칩을 장착하여 인식 거리를 측정한 결과 태그의 방향과 무관하게 1.7${\~}$2.4 m의 고른 인식 능력을 보였다.

• 한국콘텐츠학회논문지
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• 제14권10호
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• pp.527-538
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• 2014

수요 예측은 영화 산업에서 매우 중요한 문제이다. 최근 들어 트위터(Twitter), 페이스북(Facebook)과 같은 소셜미디어의 비정형 텍스트 데이터를 이용하여 영화 흥행을 예측하고 분석하는 시도들이 활발하게 이루어지고 있다. 기존에는 주로 데이터의 주기별 변화량을 측정하여 데이터 양과 영화 흥행간의 상관성을 분석하거나 데이터에 대해 감성의 극성 값을 부여하는 오피니언 마이닝을 통해 영화의 흥행 추이를 예측하였다. 하지만 이러한 정량적 접근만으로는 관객들이 영화를 선택하게 된 근거나 영화의 어떤 속성을 선호하는지를 알 수 없기 때문에 영화의 흥행 요인을 밝히는데 한계가 있었다. 따라서 본 연구는 트위터 데이터를 수집한 후 빈도수 측정을 통해 트윗의 내용을 대표하는 토픽(topic) 키워드를 추출하여 관객들의 관심을 반영하는 영화적 속성들이 무엇인지를 밝히고, 그 속성들에 대한 관객들의 반응을 분석함으로써 영화의 흥행에 영향을 미친 요인들을 제시한다.

• Asian-Australasian Journal of Animal Sciences
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• 제18권4호
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• pp.516-523
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• 2005

The experiment was conducted to study the effect of dietary combinations of vitamin A (VA), vitamin E (VE) and methionine (Met) on growth performance, meat quality and immunity in commercial broilers. Ross chicks (n=3,630) were allocated to five experimental treatments with three replicates per diet. The dietary treatments were: VA 8,000 IU, VE 10 IU (diet 1); VA 12,000 IU, VE 10 IU (diet 2); VA 8,000 IU, VE 100 IU (diet 3); VA 12,000 IU, VE 100 IU (diet 4) and; VA 12,000 IU, VE 100 IU/kg diet and 20% Met higher than other groups (diet 5). The Met content in diet 1 to diet 4 were as per the requirement suggested by NRC. Separate vitamin premixes were prepared for each treatment diet as per the requirement of study. The 35 d study revealed significantly (p<0.0001) higher weight gains in broilers fed diet 3 and diet 5, than in the rest of the groups during starter phase (0-3 weeks) only. The feed intake did not vary significantly at all phases of study, but feed efficiency was significantly (p<0.05) lower in diet 1 during starter and overall phase (4-5 weeks). The bone strength and bone composition, except bone calcium, remained unaffected due to experimental diets studied after 35 d of experimental feeding. The thio-barbituric acid reactive substances (TBARS) were significantly (p=0.0013) lower in the breast meat in group 5, followed by group 3, than in the rest of the groups. The immune studies conducted, antibody titers to sheep red blood cells, thickness index to phytohaemagglutinin-P, and heterophil: lymphocyte ratio, did not show any significant difference among treatments. It could be concluded that supplementation of VA, VE and Met at higher levels could be beneficial to broilers only during the starter phase.

• 대한수의학회지
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• 제42권1호
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• pp.65-71
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• 2002

We have utilized the PCR-RFLP method to detect the ryanodine receptor(RYR1) gene mutation and to estimate the genotype frequencies of the RYR1 gene in commercial crossbred pig population. The exon region(659bp) including point mutation(C ${\rightarrow}$T; Arg ${\rightarrow}$Cys) in the porcine ryanodine receptor gene, which is a causal mutation for PSS, was amplified by PCR and digested with Cfo I restriction enzyme. The RYR1 gene was classified into three genotypes by agarose gel electrophoresis. The normal homozygous(NN) individuals showed two DNA fragments consisted of 493 and 166bp. The mutant homozygous(nn) individuals showed only one DNA fragment of 659bp. Also, all three fragments(659, 493 and 166bp) were showed in heterozygous(Nn) carrier animals. The proportions of normal, carrier and PSS pigs within crossbred population of pigs were 81%, 15% and 4%, respectively. According to the results of analysis of variance for the association of genotypes of RYR1 of pigs at 30kg, day age at 90kg and average daily gains, the RYR1 nn genotype was very higher than RYR1 NN genotype for day age at 30kg with 5% level of significant difference, but no significant difference for association of any other genotypes with day age at 90kg and average daily gain in crossbred pigs. Therefore, DNA diagnosis by using PCR-RFLP analysis for the PSS gene was useful for large-scale screening of commercial pigs in the swine industry.

• 멤브레인
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• 제23권1호
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• pp.24-44
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• 2013

MBR 기술은 지난 20여 년 동안 처리성능과 효율성 그리고 비용절감 측면에서 빠른 속도로 발전하고 있다. 또한 안정적인 하수처리와 하수재이용관점에서 핵심기술로 널리 인식되고 있다. 본고에서는 MBR 기술의 개발과 상업적 응용에 관한 발전과정을 재조명하고 세계 시장의 전망을 제시하고자 한다. 주요 적용기술에 대해 다음 5가지 측면에서 검토하여 제시하였는데 1) MBR 기술의 진화, 2) MRBs의 상업용 기술, 3) 대용량 MBR 플랜트 설치 사례, 4) MBR 시장의 성장, 5) 기술의 발전방향 순으로 제시하였다. 마지막으로 MBRs에 대한 경제적, 환경적, 그리고 기술적 측면에서 향후 발전방향을 1) 초기투자비, 2) 처리 수질, 3) 분리막 소재/모듈, 4) MBR 장비와 공정, 5) 운영비용, 향후 6) 혐기성 MBRs 공정과 같은 차세대 기술 분야로 나누어 제시하였다.

• 한국수산과학회지
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• 제45권2호
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• pp.139-145
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• 2012

Two feeding trials were conducted to evaluate the effects of experimental extruded pellets (EEPs) and commercial EPs (CEPs) on Far Eastern catfish $Silurus$ $asotus$ in pilot- (experiment I) and commercial-scale (experiment II) tanks. Four diets were prepared: three EEPs (EEP1, EEP2 and EEP3) that contained different amounts of tuna fish meal, soybean meal, and squid liver oil, and one CEP diet. In experiment I, three replicate groups of juveniles were fed one of the four EPs in pilot-scale tanks for 19 weeks. The weight gains (WGs) of fish fed EEP1 and CEP were significantly higher than those of fish fed EEP2 or EEP3. The highest feed efficiency (FE) was observed in fish fed the CEP diet ($P$<0.05), and the FE of fish fed EEP1 and EEP3 were significantly higher than that with EEP2 ($P$<0.05). In experiment II, juveniles were fed one of four EPs in commercial-scale tanks for 19 weeks. WG and FE values of fish fed EEP1 and CEP were higher than those of fish fed EEP2 and EEP3. The results of this study indicate that the dietary formulation used in EEP1 could be used as a practical feed for Far Eastern catfish.