• Journal of Environmental Health Sciences
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• v.31 no.4 s.85
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• pp.322-326
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• 2005

연속반응조에서의 수소생산에 대한 수리학적체류시간(희석율, D)의 영향을 $1\%$ sucrose를 함유한 $37{\pm}1^{\circ}C$ 조건에서 조사하였다. 실험결과 수리학적체류시간(희석율)의 각각의 조건에 따라 생성된 가스중 수소성분은 $50~71\%$의 범위로 발생되었다. $H_2/CO_2$ 비율은 희석율이 증가할 때 $H_2/CO_2$ 비율도 증가하였다. 최대수소생성 수율은 희석율 0.14 l/h까지는 증가하다가 이후에는 감소하였고, 수소생성 수율은 0.81 l/g sucrose이었다. Acetate 생성 수율은 butyrate생성 수율 보다 희석율 조건변화에 민감하게 변화하였다. propionate 및 solvents는 희석율 변화에 영향을 받지 않았다 biomass 수율은 희석율이 0.2 l/h 까지는 증가하였으나, 그 이상의 조건에서는 감소하였다.

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.4
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• pp.105-113
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• 2003

Successful operation of a reactor can be accomplished when it is operated at proper D depending on the state of degradation. Operation at high D leads to the washout of biomass in the reactor while operation at low D leads to product inhibition due to the accumulation of excess VFA. These appear to limit the production of hydrogen to reach a higher level. Operation by D control was performed to improve the efficiency of hydrogen fermentation of food waste. Although simple organic matters were rapidly degraded in the early stage (day 1-2), proper VFA concentration and pH values were kept in the reactor at D of $4.5d^{-1}$, which was previously reported to be optimum initial D. High butyrate/acetate (B/A) ratios over 3.2 were obtained. Without D control, the reduction of simple organic matters after day 2 caused the decrease of VFA production and the increase of pH. Hydrogen production also decreased, as microbial proliferation was less than microbial loss by washout. However, the reactor performance was dramatically improved at D control from 4.5 to $2.3d^{-1}$. It showed the highest B/A ratios over 2.0 among the reactors on day 4-7. The second hydrogen peak appeared on day 4, resulting in the highest fermentation efficiency (70.8%) among the reactors. It was caused by the enhanced degradation of slowly degradable matters. The COD removed was converted to hydrogen (19.3%), VFA (36.5%), and ethanol (15.0%). Therefore, the strategy using D control, depending on the state of degradation, was effective in improving the efficiency of hydrogen fermentation.

• Proceedings of the Korean Society of Tobacco Science Conference
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• 1998.10a
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• pp.13-13
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• 1998

• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.3
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• pp.87-95
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• 2003

Although extensive studies were conduced on hydrogen fermentation of organic wastewaters, little is known about biohydrogen production from organic solid wastes. The leaching-bed reactor treating food waste by heat-shocked anaerobic sludge was, therefore, operated at D of 2.1, 3.6, 4.5 and $5.5d^{-1}$ to find optimal D for hydrogen production. Successful operation of a reactor can be accomplished when it is operated at proper dilution rate (D). Operation at high D leads to the washout of biomass in the reactor while operation at low D leads to product inhibition due to the accumulation of excess VFA. These appear to limit the production of hydrogen to reach a higher level. All the reactors showed that, on day 1-3, hydrogen production was dominant and VFA concentration was higher than ethanol. Butyrate and acetate were major components of VFAs over the whole operation, though lactate was very high on day 1-2. Compared with other D values, D of $4.5d^{-1}$, resulted in higher butyrate/acetae (B/A) ratios during the fermentation. The trend of B/A ratios was similar to the hydrogen production, suggesting that butyrate formation favored hydrogen production. Ethanol increased significantly from day 4 when hydrogen Production stopped. It indicated that heat-shocked sludge was able to induce a metabolic flow from hydrogen-and acid-producing pathway to solvent-producing pathway. Operation at D of $4.5d^{-1}$ led to higher fermentation efficiency (58%) than those (51.5, 55.3 and 53.7%) at 2.1, 3.6 and $5.5d^{-1}$. The COD removed was convened to hydrogen (10.1%), VFA (30.9%), and ethanol (17.0%).

• Korean Journal of Poultry Science
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• v.44 no.1
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• pp.59-65
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• 2017

This study examined factors affecting the analysis of motility of chicken semen. The viability of spermatozoa was estimated using varying dilution ratios and supplementation with BSA or fatty acid free (FAF)-BSA as protein sources in semen diluent. Fresh semen was examined after preparing dilutions in beltsvile poultry semen extender (BPSE) of 1/8, 1/16 and 1/32 at $25^{\circ}C$. The motility of incubated semen at each dilution was observed at 3 min (89.9%, 69.9% and 53.2%), 30 min (86.7%, 71.4% and 51.7%), 1 h (89.5%, 74.0% and 53.5%) and 3 h (78.5%, 66.5% and 45.7%), respectively. The addition of BSA or FAF-BSA to BPSE diluent significantly increased the viability of semen in 1/32 dilution with results of 53.2% (control), 84.8% (BSA) and 92.9% (FAF-BSA) (p<0.05). This phenomenon was also observed in the dilution of frozen semen, where FAF-BSA treatment increased the viability of thawed semen from 17.6% to 34.0% in a 1/8 dilution (p<0.05). When the protein sources were used in the dilution, the survival rates of diluted chicken semen were also increased with time lapse. These results show that FAF-BSA may act to protect chicken semen and is suitable as a basic component of chicken semen diluent for the method of analyzing rooster semen after freezing.

• KSBB Journal
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• v.4 no.3
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• pp.253-258
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• 1989

It was investigated that the influent sugar concentration and the dilution rate have an influence on the ethanol fermentation characteristics at steady state in a chemostat culture of K. fragilis using Jerusalem Artichoke juice as substrate. And also the optimum condition of high ethanol productivity and low residual sugar output in the ethanol production by K. fragilis, was clarified to be given at a dilution rate of 0.22/hr and at an influent sugar concentration of 85g/l.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2001.05a
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• pp.307-310
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• 2001

• Journal of Embryo Transfer
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• v.20 no.1
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• pp.43-48
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• 2005

This experiment was carried out to investigate the extender, cooling rate and concentration of glycerol for freezing of boar semen. The result obtained were summarized as follows: 1. Optimal cooling rate was $0.17\~022^{\circ}C/min$ from 25 to $5^{\circ}C$ in LEY extender on the viability and normal acrosome after thawed. 2. The LEY extender was effective in protecting frozen boar semen from cold shock among the extenders(p<0.001, respectively). 3. The sperm viability and normal acrosome rates after thawing was showed greater in the 3 or $4\%$ of glycerol concentration than $2\%$ in LEY extender. 4. Viability of sperm was higher when both 15mM of fructose and 3 or $4\%$ glycerol were added to the LEY extender compared with other concentrations of fructose and glycerol were added it(p<0.001).

• Journal of the Korea Organic Resources Recycling Association
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• v.15 no.3
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• pp.97-105
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• 2007

This study was conducted to compare the performances of acidogenic fermentation and hydrogen fermentation using bench-scale leaching-bed reactors for organic solid waste. Acidogenic fermenters were operated with dilution rates (D) of 2.0, 3.0 and $4.0d^{-1}$ after employing anaerobic sludge and hydrogen fermenters were operated with D of 2.0, 4.0 and $6.0d^{-1}$ after employing heat-treated anaerobic sludge. The highest chemical oxygen demand (COD) conversion efficiency (56.2%) was obtained in acidogenic fermentation with D of $3.0d^{-1}$. Only volatile fatty acid (VFA) was produced as a metabolite. On the other hand, hydrogen fermentation did not show higher COD conversion efficiency (49.3%) than acidogenic fermentation, but it produced hydrogen gas (5.1% of total COD) which was a clean and environmentally friendly fuel with a high energy yield. Therefore, either acidogenic fermentation or hydrogen fermentation could be applied to organic solid waste depending on the purpose of treatment, which could maximize the economics of anaerobic treatment.

• Development and Reproduction
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• v.7 no.1
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• pp.9-13
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• 2003

A series of experiments were conducted to compare the effects of various diluents in cold storage on the sea urchin, Hemicentrotus pulcherimus sperm. Various diluents of glucose solutions, artificial sea water(ASW) and 50% ASW were used to store the sperm at 4$^{\circ}C$. The storage effect was evaluated using sperm activity index(SAI), survival rate of sperm and fertilization rate to egg. ASW and 1.2 M glucose were found to be better diluents which maintained high motility and survival rate of sperm f3r a storage period of 30 days. Optimal pH of diluent to store the sperm at 4$^{\circ}C$ is 7.0∼8.0. In order to keep high SAI and survival rate of sperm, addition of 400 ppm neomycin into the diluent revealed the best storage results.