• 한국식품위생안전성학회지
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• 제26권3호
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• pp.214-221
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• 2011

2010년 유통사료 113점에 대하여 곰팡이독소 오염도 조사를 실시하였다. 면역친화컬럼(IAC)을 이용하여 각각 정제하였으며, HPLC/DAD와 FLD를 연결하여 동시분석하였다. DON은 200과 1,000 ${\mu}g/kg$수준에서 각각 95.40과 88.76%의 회수율과 4.03과 1.40%의 상대표준편차(%RSD)를 나타내었다. ZEN은 100과 500 ${\mu}g/kg$ 수준에서 각각 87.09과 98.40%의 회수율과 9.01과 2.81%의 상대표준편차(%RSD)를 나타내었다. 배합사료인 닭사료, 돼지사료, 소사료에서 DON과 ZEN이 각각 372.1, 324.0, 990.9 ${\mu}g/kg$와 76.1, 43.7, 196.2 ${\mu}g/kg$의 평균오염도를 보여 2009년도 조사결과보다 높은 오염수준을 나타내었다. 옥수수, 단백피, 주정박, 옥수수배아박, 옥수수글루텐에서는 DON과 ZEN이 각각 224.6, 3150.4, 721.5, 37.8, 207.3 ${\mu}g/kg$와 77.8, 308.5, 163.1, 116.9, 510.8 ${\mu}g/kg$로 나타남에 따라 역시 배합사료에 곰팡이독소를 오염시키는 주 원인물질로 확인되었다.

• 한국축산시설환경학회지
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• 제18권3호
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• pp.137-144
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• 2012

본 연구는 유산균과 효모로 구성된 혼합 생균제를 양돈 사료에 첨가하여 양돈용 발효사료를 제조하기 위한 최적 발효조건 구명 및 발효사료 급여에 의한 돼지 장내 환경변화를 평가하고, 원료사료별 발효능을 측정하기 위해 수행되었다. 1. 양돈 발효사료의 유산균과 효모 수를 측정하였을 때 사료 내 혼합 생균제 첨가수준은 0.25%, 수분 함량은 40~50% 정도가 적정하였다. 2. 비육돈에 발효사료를 급여하였을 때가 발효되지 않은 사료를 급여하였을 때보다 소화율은 유의적인 차이가 없었지만 분 중 휘발성지방산의 농도가 높게 나타났다. 3. 양돈용 단미사료의 발효특성을 확인하기 위하여 휘발성지방산의 농도를 측정한 결과, 비트펄프와 타피오카가 우수한 발효기질로 확인되었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.20-23
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• 2002

In silicon wafer manufacturing process, the grinding process has been adopted to improve the quality of wafer such as flatness, roughness and so on. This paper describes the effect of grinding process on the surface quality of wafer. The experiments are carried out by high precision in fred grinder with air bearing spindle. The relationship between the inclination of chuck table and the flatness of wafer is investigated, and the effect of grinding conditions including wheel speed, table speed, and feed rate on damage depth and roughness of wafer is also investigated. The experimental results show that there is close relationship between the inclination of the chuck table and the flatness of wafer, and the grinding conditions within this paper little affect the flatness of wafer and relatively high affect the damage depth of wafer.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.89-92
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• 2000

Laser claddmg 1s thc deposition of material on the surface of a part or workpiece. Cladding of metals produces a 100% dense metallurgically-bonded coating with minimal dilution for enhanced corrosion, abrasion and wear resistance. Despite of minimal heat Input and reduced processing time, cladding quality 1s affected by various process condition such as laser power and feed rate. Therefore, it is necessary to develop the momtoring and control methods of laser cladding process for the best cladding quality. In this paper, laser cladding monitoring system using CCD camera for measuring cladding pool shape, and photo-diode sensor for detecting optical signal emitted from the cladding front is introduced The variables extracted using this system can be apphed to control the laser cladding system to achieve the best claddmg results..

• Journal of Welding and Joining
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• 제31권1호
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• pp.26-32
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• 2013

Recently, welding technology of nonferrous metals which were difficult to implement by arc welder has become available through digitalization of arc welding machine. Among them, the welding quality improvement of aluminum welding is very noticeable. These results increase the arc stability by controlling arc current and voltage waveform precisely, and control wire feed speed by synchronizing with arc current which the feed rate of filler wire is controlled by a precise motor control of servomotor and not by a simple constant speed feeding. Not only through the hardware digitalization of arc welding machine but also through advance of software of arc welding, it became possible to implement a certain level of welding quality by a simple operation. These led to CMT welding process implementation which requires low heat input than current arc welding and highly increased the applicability of the aluminum welding.

• 한국정밀공학회지
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• 제13권1호
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• pp.78-83
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• 1996

This paper presents the characteristics of surface roughness and cutting force in ultraprecision cutting of aluminium alloy using natural diamond tools whose edge radii are smaller than those of tools made of other materials. The feed rate and depth of engagement were set to be a micrometer order. After measuring the surface roughness of machined surface and cutting force for each cutting condition, the relations between the surface quality and its condition were investigated qualitatively. If the feed rate was under a certain limit, the machined surface quality was deteriorated unexpectedly. This is supposed to have happened due to vibration leading its condition to abnormal one. In a certain situation the machined surface roughness by a natural diamond tool was inferior to that made by a carbide tool whose cutting edge radius is larger. This is supposed to be caused by not normal machining but burnishing effect.

• 반도체디스플레이기술학회지
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• 제16권1호
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• pp.59-64
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• 2017

The general manufacturing problem can be described as the achievement of a predefined product quality with given equipment, cost and time constraints. Unfortunately, for some quality characteristics of a product such as surface roughness it is hard to ensure that these requirements will be met. Stainless steels STS 304 is frequently used as shaft materials in small fiber reinforced polymer(FRP) fishing boats. In this work, the dry turning parameters of STS 304 are optimized by using Taguchi method. The experiments were conducted at three different cutting speeds with three different feed and three different depth of cut. The cutting parameters are optimized using signal to noise ratio and the analysis of variance. The effects of cutting speed and feed on surface roughness was analyzed. The results revealed that the spindle speed is the more significant parameter influencing the surface roughness.

• 분석과학
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• 제37권2호
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• pp.79-86
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• 2024

Among the nutrients in feed, amino acids and minerals are important for the growth and development of pets. In particular, interest in nutritional components related to the health of pets is increasing as pet-raising households and pet food markets have recently grown. Therefore, in this study, 55 pet food products distributed in South Korea were purchased, and the content of 3 essential and conditionally essential amino acids (taurine, lysine, arginine) and 4 minerals (Ca, P, Na, K) was investigated. Among the three amino acids, arginine was found to have the highest content, and the average content was 1.79 and 1.37 % in cat and dog foods, respectively. On the other hand, the taurine content was the lowest, but it was found to be higher than the minimum requirement of 0.10 % for cats set by the American Association for Feed Control (AAFCO) and the European Federation of Pet Food Industries (FEDIAF). As a result of the four-component analysis of minerals, the content of Ca was found to be the highest, and the average content was confirmed to be 1.64 and 1.25 % in cat and dog food, respectively. On the other hand, Na was the lowest, but it was higher than the AAFCO minimum requirement and FEDIAF minimum requirement for young cat and dog food. Among all 55 samples examined, the content of the three amino acids and the four inorganic components was confirmed to be suitable for the recommended minimum intake and maximum allowable intake presented by AAFCO and FEDIAF.

• Journal of Power Electronics
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• 제8권2호
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• pp.109-120
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• 2008

In this paper, a novel delta/double-fork transformer based 18-pulse full-wave AC-DC converter is designed, modeled, simulated and developed to feed isolated DC varying loads. The proposed AC-DC converter is used for low voltage and large current DC loads in applications such as electrowinning, where isolation is required mainly for stepping down the supply voltage. The proposed converter improves power quality at AC mains and meets IEEE-519 standard requirements at varying loads.

• 한국가금학회지
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• 제14권1호
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• pp.39-53
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• 1987

본시험은 산란계사료의 에너지 및 단백질수준이 산란성적, 생존율, 란질, 영양소이용율 및 복강지방 축적율 등에 미치는 효과를 구명하기 위하여 대사에너지 3수준(2,500, 2,700, 2,900 kcal/kg)과 단백질 3수준(13, 15, 17%)을 조합한 9개처리에 720수씩 2회에 걸쳐 1,440수를 공시하였으며, 1차시험은 1982년 5월 5일부터 1983년 5월 3일까지, 2차시험은 1983년 12월 28일부터 1984년 12월 26일까지 각각 52주간에 걸쳐 시험을 실시하였던 바 그 결과를 요약하면 다음과 같다. 1. 산란율은 대사에너지수준이 증가할수록 점차 감소하였고 단백질 수준이 증가할수록 점차 증가하였지만 (P〈0.05), 단백질 15%와 17%수준간에는 큰 차이가 없었다. 2. 란중은 에너지 수준에 따라서 차이가 없었으나 단백질수준이 증가할수록 증가하였지만 15%와 17%수준간에는 차이가 없었다. 3. 사료섭취량은 에너지 수준이 증가할수록 점차 감소하였다. 4. 사료요구율은 에너지 수준간에는 큰 차이가 없었지만 단백질 수준이 증가할수록 점차 개선되었다. 5. 산란 kg당 사료비는 에너지수준이 증가할수록 점차 증가하였으며 단백질수준간에는 차이가 없었다. 6. 증체량은 대시에너지 2,500kcal/kg 수준에 비하여 2,700 및 2,900kcal/kg 수준에서 증가하였고, 단백질 13%수준에 비하여 15 및 17%수준에서 증가하였다. 7. 생존율은 에너지수준이나 단백질수준에 따라 차이가 없었다. 8. 란각질은 에너지수준이 증가함에 따라 점차 떨어지는 경향이었으나 단백질수준간에는 차이가 없었다. 9. 란황차색도는 에너지수준에 따라서는 차이가 없었지만 단백질수준이 증가함에 따라 점차 증가하는 경향이었다. 10. 단백질을 제외한 모든 영양소의 이용율은 에너지 수준이 증가함에 따라 증가하였지만, 단백질수준에 따라서는 건물의 이용율만 감소하는 경향이었고 다른 영양소의 이용율은 차이가 없었다. 11. 복강지방축적율은 에너지수준이 증가할수록 점차 증가하는 경향이었다. 이상의 결과를 종합하여 볼 때 우리나라의 사료적 여건이나 환경적 여건하에서 산란계사료의 대사에너지 수준은 2,500kcal/kg, 단백질수준은 15%가 적합할 것으로 사료된다.