• 한국식품영양학회지
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• 제26권4호
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• pp.753-758
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• 2013

메밀 속성 장 프리믹스의 최적 조건을 확립하고자 품질특성을 조사하였다. 소금량(8, 10, 12%)에 따른 품질특성 결과, 대장균 군수는 소금량 10, 12%(21일), 8%(28일) 이후로 검출되지 않았으며, B. subtilis HJ18-4를 starter로 첨가한 군은 발효 7일부터 검출되지 않았다. 아미노태 질소 함량은 21일까지 급격히 증가하였으며, 그 후로 완만히 증가하였다. 그 결과, 소금 함량 10%, starter 첨가 시 보다 안전한 발효가 이루어졌다. 가수량(1:1, 1:1.5. 1:1.8)의 따른 품질특성 결과, 총균수와 아미노태 질소 함량은 가수량이 적을수록 높았으며, 1:1 혼합(35일)일 때 아미노태 질소 함량은 169.5mg%로 가장 높았고, 발효 28일 이후 대장균 군이 검출되지 않았다. 용기별(항아리, 유리, 플라스틱)의 품질특성 결과, 총균수와 아미노태 질소 함량은 유리 용기 대비 플라스틱과 항아리 용기가 높았으며, 대장균군도 보다 빨리 감소하였다. Batch size(1.25 kg, 2.5 kg)를 달리하여 제조된 메밀 속성 장의 품질특성 결과, 총균수와 아미노태 질소 함량은 batch size에 따른 큰 차이가 없었으며, 대장균 군 측정 결과, 14일째 2.5 kg($3.00{\times}10^2$ CFU/g), 1.25g ($1.25{\times}10^3$ CFU/g)으로 나타났다. 메밀 속성 장 프리믹스의 최적 조건은 가수량 1:1, 소금의 양 10%, B. subtilis HJ-18-4를 starter로 첨가, 항아리 및 플라스틱 용기는 3주, 유리 용기는 4주 발효시키는 것이 바람직하였다.

• Animal Bioscience
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• 제34권4호
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• pp.701-713
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• 2021

Objective: The present work was undertaken to evaluate the effects of storage time, choline chloride, and high concentrations of Cu and Zn on the kinetic behavior of vitamin degradation during storage in two vitamin premixes and four vitamin-trace mineral (VTM) premixes. Methods: Two vitamin premixes (with or without 160,000 mg/kg of choline) were stored at 25℃ and 60% humidity. Besides, four VTM premixes were used to evaluate the effects of choline (0 vs 40,000 mg/kg) and trace minerals (low CuSO4+ZnO vs high CuSO4+ZnO) on vitamin stability in VTM premixes stored in room, and the VTM premixes were stored in room temperature at 22℃. Subsamples from each vitamin and VTM premix were collected at 0, 1, 2, 3, 6, and 12 months. The retention of vitamin A (VA), vitamin D3 (VD3), vitamin E (VE), vitamin K3 (VK3), vitamin B1 (VB1), vitamin B2 (VB2), vitamin B3 (VB3), vitamin B5 (VB5), and vitamin B6 (VB6) in vitamin premixes and VTM premixes during storage was determined. The stability of vitamins in vitamin premixes and VTM premixes was determined and reported as the residual vitamin activity (% of initial) at each sampling point. Results: The effect of choline on VK3 retention was significant in vitamin premixes (p<0.05). The negative effect of storage time was significant for the retentions of VD3, VK3, VB1, VB2, VB5, and VB6 in vitamin premix (p<0.05). For VTM premixes, negative effect of storage time was significant (p<0.05) for the losses of vitamin in VTM premixes. Choline and high concentrations of Cu and Zn significantly increased VA, VK3, VB1, and VB2 loss during storage (p<0.05). The supplementation of high concentrations of Cu and Zn significantly decreased the concentrations of VD3 and VB6 (p<0.05) in VTM premixes at extended storage time. Conclusion: The maximum vitamin stability was detected in vitamin and VTM premixes containing no choline or excess Cu and Zn. The results indicated that extended storage time increased degradation of vitamin in vitamin or VTM premixes. These results may provide useful information for vitamin and VTM premixes to improve the knowledge of vitamin in terms of its stability.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.641-646
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• 1997

Polymer cement mortar which is used as material for aging concrete structures is generally mixed manually and applied on the job site. but, to secure the required quality of the mortar, pre-mixed polymer cement mortar is favored. This study was initiated to four different pre-mixed polymer cement mortars which are produced in Korea. The for pre-mixed mortars were selected and tested with respect to physical and mechanical properties an proved that their qualities were better than those of common cement concrete mortars.

• 대한기계학회논문집B
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• 제37권2호
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• pp.161-170
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• 2013

Double cone 버너를 장착한 스월 예혼합 연소기에 대한 유동 및 연소 특성을 분석하여 swirler 모델을 이용한 수치적 모델링 방법을 제시하였다. 버너 출구에서 형성되는 내부 재순환 영역을 근사적으로 구현하도록 swiler의 내 외경을 각각 56 mm, 152 mm로 결정하였으며 이를 토대로 유량, 반경 반향 속도를 결정하였다. 접선 방향 속도의 설정을 위해 swirl 각도와 재순환 각도를 도입하였으며 40 m/s인 경우 유사한 내부 재순환 영역이 형성되었다. 라이너 출구에서 온도와 속도의 오차는 각각 2.8%, 0%로 작았지만, NOx의 경우 67% 가량 감소한 결과를 보였다. Swirler 모델은 EV 버너의 유동 및 연소 특성을 근사적으로 모사하는 모델의 하나로서 정량적 평가 인자에서 오차를 보이지만, 유동 및 화염, NOx 형성 영역의 경향성이 유사하므로 swirler 모델을 채택하여 복잡한 형상의 발전용 가스터빈 연소기의 효율적인 수치해석이 타당할 것으로 판단된다.

• 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%.

• 한국가금학회지
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• 제34권1호
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• pp.43-52
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• 2007

육계 사료에 허브와 식물체의 추출물의 첨가가 생산능력, 영양소 소화율, 장내 미생물, IgG, 혈액의 조성에 미치는 영향을 구명하고자 2차례의 실험을 수행하였다. 시험 1은 대조구, 항생제($Aviilamix^{(R)}premix-avilliamycin$ 0.02 %) 0.03%구, Herb M (Herb $mix^{(R)}$-지황 10%, 산약 10%, 당귀 20 %, 오미자 5%, 감초 5%, 천궁 10%) 0.2%구, Plant extract B(BIOSTONG $510^{(R)}-Anise$ Extract 20%, Thyme Extract 17%, Quillaja 30%) 0.02%구, Plant Extract A($APEX^{(R)}$ - garlic, anise, cinnamon rosemary, thyme, Talin등 50%) 0.02%구 등 5개 처리구를 두었다. 시험 2는 대조구, 항생제($Aviilamix^{(R)}$premix- avilliamycin 0.02%) 0.03% 구, Plant Extract D($Digestarom^{(R)}$-peppermint oil, gentian, horse-tail herb, saponins, oak bark 50 %) 0.02 %구, Plant extract P($Phellozyme^{(R)}$ -Kilmora lavan extract, bromelain extract, bioflavonoid, propolis 15%) 0.1%구, Plant Extract G($Galicin^{(R)}$-allicin 10%) 0.05%구, Plant Extract C(CRINA $POULTRY^{(R)}$-cinnamon, lemongrase, savory, rosewood, spearmint, tea) 0.05%구 등 6개 처리구를 두었다. 시험 1은 1일령 육계($Ross^{(R)}$종) 1,000수(암 수 각각 500수)를 공시하여 5처리 4반복 반복당 50수(암 수 동수) 씩을 floor pen(가로: 2.0 m, 세로: 2.4 m)에 완전 임의 배치하였다. 시험 2는 1일령 육계($Ross^{(R)}$종) 240수(암 수 각각 120수)를 공시하여 6처리 4반복, 반복당 10수(암 수 동수) 씩을 케이지(가로: 35.5 cm, 세로: 45 cm, 높이: 55 cm)에 완전 임의배치하여 각각 35일간사양 시험을 실시하였다. 시험 1에서 생산지수는 대조구에 비해 첨가구들이 높은 경향이 있었고 herbs M구가 가장 높았다. 시험 2에서 $4{\sim}5$주 사료 섭취량은 대조구에 비해 첨가구들이 유의적으로 높았다(P<0.05) 사료 요구율은 항생제 처리구가 다른 처리구보다 낮았다. 시험 1의 RBC와 적혈구 용적 (HCT 또는 PCV), Hb는 첨가구들이 대조구보다 유의적으로 높았다(P<0.05). 시험 2의 BA는 대조구보다 첨가구들이 유의적으로 낮았다(P<0.05). 시험 1과 시험 2의 혈청 IgG 농도는 대조구에 비해 첨가구들이 유의적으로 높았다(P<0.05). 시험 1과 시험 2의 장내 미생물 균총과 영양소 이용율은 처리간에 통계적 차이가 없었다. 결론적으로 일부 한방제와 생약제제는 육계에서 항생제를 대체하여 사용이 가능하며 특히 혈액의 성분에 유의한 영향을 미치는 것으로 사료된다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
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• pp.247-253
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• 2003

Burning velocities of conventional methane flame and oxygen-enriched methane flame were determined by experimentally and numerically at atmospheric pressure in order to examine the validity of various detailed reaction mechanisms in oxygen-enriched flame. The schlieren system was adopted to obtain the burning velocity of flame stabilized on a circular nozzle. Premix code was employed to compute the burning velocity. Three reaction mechnisms were tested at several oxygen enrichment level, whose names are GRI 3.0, MB(Miller and Bowman) and LKY(Lee Ki Yong) reaction mechanism. Sensitivity analysis was also performed to discriminate dominantly affecting reaction on burning velociy. The results showed that conventional reaction mechanisms originally based on methane-air flame were underpredict the burning velocity at high oxygen-enrichment level. The modified GRI 3.0 reaction mechanism based on our experimental results was suggested and shows a good agreement in estimating the burning velocity and the NO number density of oxygen-enriched flame.

• 한국산업융합학회 논문집
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• 제9권1호
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• pp.21-27
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• 2006

The laminar burning velocity was measured using a spherical combustion bomb with central ignition. Mixtures with equivalence ratio between 0.6 and 1.2, were tested. The computation was carried out for the burning velocity using premix code of Chemkin program under the unburned gas pressure of 0.5bar-30bar and temperature of 300K-700K at ${\Phi}1.0$. The results showed little difference between these two methods. The burning velocity was decreased by increasing the pressure and increased by increasing the temperature. The burning velocity was predicted by using the following equations $$S_L(m/s) = S_{st}(T/300)^{1.85}(P)^{-0.45}$$ $$(0.5bar{\leq}P{\leq}30bar,\;300K{\leq}T{\leq}700K)$$).

• 한국연소학회지
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• 제17권2호
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• pp.1-8
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• 2012

Laminar flame speeds of Methane at elevated temperatures and pressures were investigated using constant volume spherical chamber. Pressure trace during combustion was measured in each test and this was used in calculating laminar flame speed of Methane. To have large amount of data, experimental apparatus was fabricated with fully automatically controlled feature. A calculating code which calculates laminar flame speeds at various temperatures and pressures with one experimental result was used to calculate laminar flame speeds. The experimental and calculating methods were verified using the calculated laminar flame speed result with PREMIX code.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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• pp.133-139
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• 2002

The lean premixed technique has been proven very efficient in reducing NOx emissions from gas turbine combustors. However combustion instability is susceptible to occur in lean premixed combustor. So laboratory-scale dump combustor was used to understanding the underlying mechanisms causing combustion instabilities. In this study, tests were conducted at atmospheric pressure and inlet air was up to $360^{\circ}C$ with natural gas. The observed instability was a longitudinal mode with a frequency of ${\sim}341.8Hz$. At selected unstable conditions, phase-resolved OH chemiluminescence images were captured to investigate flame structure with various equivalence ratio. Combustion instability was observed to occur at higher value of equivalence ratio(>0.69). This study was performed to investigate the effects of equivalence ratio and fuel split measuring NOx and acoustic wave. The results reveal the effect of fuel-air unmixedness on lean premixed combustor.