• 대한기계학회논문집A
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• 제39권9호
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• pp.839-849
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• 2015

본 논문은 밀링가공에서 측정되는 절삭력 진동을 분석함으로써 가공조건을 모니터링하는 실험적 기술을 다룬다. 이 기술은 앞서 보고된 절삭력 진동의 이송속도 및 절삭깊이와의 관계에 근거한다. 측정 시스템은 동적 힘 센서와 신호 증폭기로 구성되고, 분석 시스템은 오실로스코프와 LabVIEW 프로그램을 갖춘 컴퓨터를 포함한다. 가공조건 중 회전속도를 일정하게 하고 이송속도와 절삭깊이를 변화시키며 실험하였다. 절삭날 수와 회전 진동수의 곱에 해당하는 절삭력 진동 성분의 크기가 가공조건과 선형으로 관계되었다. 이로써 이송속도와 절삭깊이 중 한 가지 가공조건을 알 때 절삭력 진동 분석을 통해 다른 한 가지 가공조건을 확인할 수 있다.

• 한국환경과학회지
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• 제3권3호
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• pp.285-296
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• 1994

The objective of this study was to examine and compare to transient response to quantitative and hydraulic shocks which produce equal changes in mass rate of organic feed in aerobic fixed-film process. The general experimental approach was to operate the system at several growth rates under steady-state(pre-shock) conditions, then to apply step changes during day 3 in dilution rate(hydraulic shock) , or feed concentration(Quantitative shock) at the same organic mass loading rate. Performance was assessed in both the transient state and the new steady-state (post- shock). Shock load of different type did not produced equivalent disruptions of effluent quality for equal increases in mass loading rate. Based on effluent concentrations, a hydraulic and a Quantitative shock at the same mass loading caused equal increase in total effluent COD, but the increase was primarily a result of suspended solids the hydraulic shock and COD in the quantitative shock. The time which effluent COD came to peak values were about 32~48 hours at the low organic loads and 52 ~ 72 hours at the high organic loads, respectively A quantitative shock produced a much greater increase in effluent COD than did a hydraulic shock at the same mass loading. Mean and peak values of effluent concentration weve increased in 2.8~4.2 times at low organic loading rate, 5.2~6.6 times at the high organic loading rate, respectively. Key words : Aerobic fixed-film reactor, Quantitative shock, hydraulic shock, mass loading rate.

• 한국재료학회지
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• 제25권9호
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• pp.442-449
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• 2015

The effects of coating parameters were investigated in wear resistance coatings of Diamalloy-406 on Inconel 718 to obtain an optimum coating condition by high velocity oxy-fuel spraying. The coating parameters, the flow rates of source gases (hydrogen and oxygen), the powder feed rate, and the spray distance, were designed by the Taguchi method. The optimal conditions were determined: oxygen flow rate 34 FRM, hydrogen flow rate 57 FRM, powder feed rate 35 g/min, and spray distance 7 inch. Friction coefficients of the coating and the substrate decreased with an increasing sliding surface temperature from $25^{\circ}C$ to $450^{\circ}C$. The friction coefficient of Diamalloy-4006 coating decreased as the sliding surface temperature increased from $0.43{\pm}0.01$ at $25^{\circ}C$ to $0.29{\pm}0.01$ at $450^{\circ}C$. The wear trace and wear depth of the coating were smaller than the substrate at all temperatures tested. The relationship between spray parameters and wear resistance was discussed extensively, based on the measured roughness, hardness, and porosity in each coating.

• Asian-Australasian Journal of Animal Sciences
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• 제22권11호
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• pp.1594-1608
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• 2009

Research on barley as an animal feed started some decades ago but its utilization in animal production has been limited to countries that grow the crop extensively. Corn has been the most popular energy feed in cattle rations, but the high price of corn and the decreased supply of the grain in the international market have shifted the focus of the animal industry to other cereal crops like barley. Studies have indicated that growth performance of cattle fed barley-based diets has been generally comparable with that of those fed corn-based diets, while results for cattle fed whole-crop barley silage have been more variable. Beef from cattle fed barley-based diets has proved to be as tender and as acceptable for taste as that from animals fed other finishing diets when compared at similar growth rates and degree of finish. The barley crop contains good amounts of antioxidants like 2"O-GIV isovitexin, so from the meat science point of view, a desirable influence of these components on meat quality traits such as meat color, oxidative stability and sensory characteristics might be expected. Furthermore, the effect of the distinctive fatty acid profile of beef fed from whole-crop barley silage on sensory traits is also an important subject to be elucidated. A lot of studies have been made over past decades on the effect of barley, and especially whole crop barley, on beef cattle production and meat quality, but these data have not been collectively documented in a review. The current review re-visits previous literature to underline the effects of barley in the diet on beef quality traits and to identify areas for further studies.

• Asian-Australasian Journal of Animal Sciences
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• 제22권3호
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• pp.448-458
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• 2009

It has been well documented from animal and human studies that conjugated linoleic acid (CLA) has numerous beneficial effects on health. In chickens, CLA exerts many effects on performance ranging from egg quality and yolk lipids to meat quality. Although there are several CLA isomers available, not all CLA isomers have the same incorporation rates into egg yolk: cis-9,trans-11 and trans-10,cis-12 CLA isomers are more favorably deposited into egg yolk than other isomers investigated, but of the two isomers, the former has a higher incorporation rate than the latter. CLA alters the amounts and profiles of lipids in plasma, muscles and liver. Furthermore, increased liver weight was reported in chickens fed dietary CLA. As observed in egg yolk, marked reduction in intramuscular lipids as well as increased protein content was observed in different studies, leading to elevation in protein-to-fat ratio. Inconsistency exists for parameters such as body weight gain, feed intake, feed conversion ratio, egg production rate and mortality, depending upon experimental conditions. One setback is that hard-cooked yolks from CLA-consuming hens have higher firmness as refrigeration time and CLA are increased, perhaps owing to alterations in physico-chemistry of yolk. Another is that CLA can be detrimental to hatchability when provided to breeders: eggs from these breeders have impaired development in embryonic and neonatal stages, and have increased and decreased amounts of saturated fatty acids and monounsaturated fatty acids (MUFAs), respectively. Thus, both problems can be fully resolved if dietary sources rich in MUFAs are provided together with CLA. Emerging evidence suggests that CLA exerts a critical impact on stress and immune functions as it can completely nullify some of the adverse effects produced by immune challenges and reduce mortality in a dose-dependent manner. Finally, CLA is a key regulator of genes that may be responsible for lipid metabolism in chickens. CLA down-regulates both expression of the gene encoding stearoyl-CoA desaturase-1 and its protein activity in the chicken liver while up-regulating mRNA of sterol regulatory element-binding protein-l.

• Asian-Australasian Journal of Animal Sciences
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• 제25권7호
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• pp.945-949
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• 2012

Yerba Mate (Ilex paraguariensis), a tea known for its high antioxidant content, was supplemented to 30 of 60 ewes for 13 wks to assess its effect on their productive performance. A 2.5% inclusion rate of Yerba Mate (YM) in a pelleted concentrate diet decreased feed intake and live weight (LW) during the first few weeks post partum (p<0.001). Overall, the YM group ate less ($2,092{\pm}78g/d$) pellet than the control (CTRL) one ($2,434{\pm}83g/d$); similarly, LW was lower in the YM group compared to the CTRL one, $64.9{\pm}1.6kg$ and $67.3{\pm}1.4kg$, respectively. Lambs' birth weight and growth rates were not affected. At birth, lambs' LW were similar between the Yerba Mate and control groups ($4.2{\pm}0.5kg$ and $4.1{\pm}0.4kg$, respectively. At the end of the trial, Yerba Mate lambs weighed $15.7{\pm}0.4kg$ while CTRL lambs weighed $16.1{\pm}0.4kg$. Average daily growth rate was similar between the two groups and ranged from $176{\pm}19$ to $234{\pm}24g/d$. The inclusion of Yerba Mate in a pelleted diet increased milk fat, protein and total solids content while it decreased milk lactose content. Further work is required to investigate the mechanisms by which Yerba Mate supplementation affects feed intake and milk composition.

• Asian-Australasian Journal of Animal Sciences
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• 제25권5호
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• pp.738-748
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• 2012

One of the main goals of small, medium and large farms is to improve the reproductive performance of rabbit does. Stocks of lower productivity can be improved by crossing with intensive breeds. A better nutritional status of both foetuses and suckling kits has a positive effect on their later productivity. Overfeeding young females before first mating can lead to conditions of fattiness. Using restricted feeding or higher fibre content in the feed and changing it for a higher level ad libitum feeding about one week prior to first mating leads to longer lifespan and higher productive level. Intensive reproductive rhythm creates a negative energy balance in does : they are unable to consume enough feed (energy) for the nutritional requirements of foetus and lactation, and therefore lose most of their fat reserves. Furthermore, primiparous does also expend energy because they are still growing. Under intensive conditions, the 42-d reproductive rhythm (re-mating 11 days after parturition) is recommended. Under extensive conditions, the 18 or 25-d mating interval with 35 to 42-d weaning could be suitable. On small farms, natural mating is favoured; on large farms AI is commonly employed. The main advantage of AI is the all-in, all-out system. Hormonal (PMSG) treatment is used with AI to increase receptivity on d 11. Frequent and high level PMSG use can lead to higher anti-PMSG antibody rates. Lower level (max. 20 IU) and less frequent PMSG injection or non-hormonal alternative methods (short dam-litter separation, changing nursing method or lighting programs) are recommended for this reason.

• International Journal of Industrial Entomology and Biomaterials
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• 제15권2호
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• pp.157-160
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• 2007

Nymph of the emma field cricket, Teleogryllus emma, were reared on several types of artificial diets. The development period of nymphs were 55.4 days when only a single food, wheat bran, was provided, and it did not show a significant difference compared to the rearing results of the Danong diet and mixed diet. The supplying period of fish meal as the animal feed, the high emergence rates were obtained at 3rd instar with 90% and 4th instar with 100%. For the added amount test, when more than 40% of the diet was added, it confirmed that the insect weight increased. The characteristics of development according to each added amount of the vegetable food (dry bean-curd residue and corn powder) were investigated to minimize the dangers of the degeneration of diet when rearing with a single feed during the $1st{\sim}3rd$ instar period. First, as the added amount of bean-curd residue increased, nymphal development period became longer and the emergence rate became low. With corn powder as the single diet, all died before becoming adult. However, when corn powder was added up to 30%, no difference existed in the breeding results.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.256-259
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• 2000

혐기성 박테리아균인 Zymomonas mobilis을 이용한 에탄올 발효에서 사용한 균주가 pH변화에 대하여 강한 내성을 지니고 있으므로 pH 변화에 대한 생산성의 변화는 나타나지 않았다. 다만 주입 기질의 농도가 증가함에 따라 생성되는 알코올의 농도도 증가함을 알 수 있으나 생산성을 고려하여 glucose의 농도가 10%일 때 가장 경제성이 있음을 알 수 있었다. 연속발효에서 glucose의 농도를 10%로 하고 CSL을 1.2%로 하여 실험한 결과 Maximum Productivity는 14.06g EtOH/L/hr을 나타냈으며 glucose의 전환율은 0.47g EtOH / g glucose을 나타냈다. 알코올의 분리 농축을 위한 투과증발 실험에서는 공급액의 유속이 482ml/min이고 공급액의 농도가 8%, 온도가 $70^{\circ}C$에서 투과물의 Flux는 $0.04kg/m^2/hr$ 이었으며 Selesctivity는 7.5로 나타났다. 5{\sim}8%$의 희석된 에탄올 수용액을 투과증발실험을 한 결과 7배 이상 농축되었다.