조사료의 종류가 홀스타인 송아지 유선의 발달 , 반추위 돌기 및 성장률에 미치는 영향

조광근,최윤재,박영우,윤연화,한영근,윤상기,권웅기 한국영양사료학회 1999 韓國營養飼料學會誌 Vol.23 No.6

본 연구는 홀스타인 송아지에 대한 세 종류의 조사료가 유선조직, 반추위 유두, 번식성적 및 성장률에 미치는 영향을 조사하기 위하여 실시하였다. 출생 후 4일된 송아지(42.9±0.9㎏) 24두를 무작위로 선발하여 출생 후 4∼44일까지 전유를 급여하다가 45일에 그룹 1은 볏짚, 그룹 2는 오차드 그래스, 그룹 3은 알괄파를 급여하였다. 또한 유선조직과 반추위의 발달을 측정하기 위하여 3, 9, 18개월령에 도달하였을 때 각 처리구의 송아지를 1마리씩 도살하였다. 알팔파를 급여한 그룹 3은 다른 처리구에 비하여 중체율이 높았으며, 그룹 2는 영양소 이용률과 번식성적이 높은 경향을 나타내었다. 반추위의 무게는 3개월령 도달시에는 그룹 3이 가장 무거웠으나, 9개월과 18개월령 도달시에는 그룹 2에서 가장 무거운 것으로 나타났다. 반추위의 유두 수는 유두의 성장과 함께 일반적으로 감소하는 경향을 나타내어 유두의 길이와 유두 수와는 서로 상대적인 관계를 나타내었다. 유선의 기능적 활성을 나타내는 RNA/DNA 함량은 3개월 시에는 그룹 3이 가장 낮은 경향을 보였으나 9, 18개월 시에는 반대로 가장 높은 경향으로 나타났으며, 유선세포의 크기를 나타내는 protein/DNA 함량은 18개월 시에 그룹 2가 가장 높은 경향을 보였다. 결론적으로 본 연구에서 볏짚은 반추위의 초기 발달을 촉진하고 알팔파와 오차드그래스는 성장과 번식성적을 증가시키며 또한 초기에 유선의 발달을 촉진시키는 것으로 나타났다. Twenty-four Holstein calves were used to evaluate the effects of three different forages on growth and reproductive performances, and ruminal papillary and mammary developments. Four-day-old Holstein calves weighing 42.9±0.9 ㎏ were randomly assigned to three forage groups of rice straw (group 1), orchard grass hay (group 2), and alfalfa (group 3). All calves received whole milk from day 4 through day 44. At 45 days of age, the animals were assigned at random to one of the three dietary treatments. When calves reached the ages of 3, 9, and 18 months, one calf in each group was sacrifced for evaluation of ruminal and mammary tissue developments. Calves of group 3 gained more body weight than those of other groups, while group 2 showed an effective nutrient utilization and reproduction performance. At 3 months, the stomach weight of group 3 was the highest, however, group 2 provided the highest stomach weight at 9 and 18 months. A remarkable reduction in papillae number was observed in the rumens of all 3- to 9-month-old heifers. A decrease in number of these papillae was observed in all groups exhibiting papillary growth. There was a reciprocal relationship between the number and the length of ruminal papillae. Among the 3-month-old calves, the functional activity (RNAI DNA contents) of the mammary glands of group 3 was lower than those of other groups, whereas the trend was opposite for 9- and 18-month-old heifers. The size of mammary cell (protein / DNA contents) was the greatest for group 2 at 18 months of age. The results suggest that rice straw stimulated earlier development of rumen. Alfalfa and orchard grass improved the growth, reproduction performance, and earlier development of mammary glands.

육성돈에서 Phytase 첨가가 Extrusion 한 쌀겨의 P 이용성에 미치는 영향

김영길,김인호,손중천,김은주,권기범,문태현 한국영양사료학회 1999 韓國營養飼料學會誌 Vol.23 No.3

본 시험은 육성돈에 있어 extrusion된 쌀겨에 대한 P의 이용성과 extrusion된 쌀겨에 phytase를 첨가하므로서 P의 이용성에 미치는 영향을 구명하고자 영양소 소화 시험을 실시하였다. Extrusion된 쌀겨와 extrusion된 쌀겨에 phytase을 첨가한 구간의 비교는 phytase의 첨가에 의해 건물 소화율이 약간 증가하는 경향을 보였다(P<0.04). N 소화율은 쌀겨구 보다는 extrusion된 쌀겨구에서 약간의 증가를 보였다(P<0.07). Ca(P<0.06)과 P(P<0.01)의 소화율은 모두 extrusion된 쌀겨에 phytase의 첨가수준이 다를 경우 500 unit보다는 1,000 mini에서 더 좋은 효과를 보였다. 분 중 P 배설량(2.72g/d vs 3.89g/d)은 extrusion된 쌀겨보다는 extrusion된 쌀겨에 phytase을 첨가하므로서 줄어들었다(P<0.08). 또한 phytase의 첨가수준이 증가할수록 P의 축적량이 증가함을 알 수 있었다(P<0.04). 한편 Ca 섭취량, 배설량 및 축적량은 모든 처리구 간에 통계적인 유의성을 찾아볼 수 없었다. 그러나 최종 Ca 축적량은 쌀겨에 비해 extrusion된 쌀겨의 경우 15%가 향상되었다(6.64g/d vs 5.77g/d). An experiment was conducted to determine the effects of microbial phytase and feed processing on production and phytate P utilization of pigs. Four crossbred barrows with average initial body weight of 30㎏ were used in 24-d metabolism experiment(4 x 4 latin square) to determine the effect of extruded rice bran and phytase supplementation on nutrient utilization. Digestibility of DM in pigs fed extruded rice bran with phytase improved compared to that in pigs fed extruded rice bran(P<0.04). N digestibility was greater for extruded rice bran than rice bran(P<0.07). However, there was no effect of phytase supplementation to extruded rice bran. Digeshbilities of Ca(P<0.06) and P(P<0.01) were greatest for extruded rice bran with phytase 1,000 unit. Fecal excretion of P(2.72g/d vs 3.89g/d) was less for extruded rice bran with phytase than without phytase(P<0.08). Also, when phytase supplementation was increased in diet, there was increased P retention(P<0.04). There were no treatment effects intake, excretion and retention of Ca. However, Ca retention improved by 15% in extruded rice bran compared to rice bran(6.44g/d vs 5.77g/d).

지하철의 사상사고 및 운전장애 분석에 관한 연구

이동훈,목연수,장성록,권혁무,윤원영,옥영석,최용석,배동철 한국산업안전학회 1999 한국안전학회지 Vol.14 No.3

The purpose of this study is to analyze death injuries and operation troubles of urban transit. No difference was shown in death rates between Line 1 of Pusan urban transit and Line 5, 7, and 8 of Seoul metropolitan transit. And relief time by another train did not depend upon the number of crews. We concluded that thorough inspection and preventive maintenance of trains and facilities are necessary for safe and timely service of urban transit.

RTCVD 법으로 성장한 Si1-xGex 에피막의 특성

김광일,배영호,강봉구,정욱진,군영규,손병기 한국센서학회 1996 센서학회지 Vol.5 No.2

The growth and characterization of heteroepitaxial Si_(l-x)Ge_x films grown by the RTCVD (Rapid Thermal Chemical Vapor Deposition) method were described. For the growth of Si_(l-x)Ge_x heteroepitaxial layers, SiH₄/ GeH₄ / H₂ gas mixtures were used. The growth conditions were varied to investigate their effects on the Si / Ge composition ratios, the interface abruptness and crystalline properties. The experimental data shows that the misfit threading dislocation in Si_(l-x)Ge_x / Si heteroepitaxial film of about 400 A thickness was not observed at the growth temperature of as low as 650℃, and the composition ratios of Si / Ge changed linearly with SiH₄ / GeH₄ gas mixing ratios in our experimental ranges. In the in-situ boron doping experiments, the doping abruptness would be controlled within several hundreds Å/decade.

RTCVD 법으로 성장한 실리콘 에피막의 특성

김광일,손병기,정욱진,권영규,배영호,강봉구 한국센서학회 1996 센서학회지 Vol.5 No.1

Silicon epitaxial films of submicron level were successfully grown by the RTCVD method. For the growth of silicon epitaxial layers, SiH₂Cl₂/ H₂ gas mixtures and various process parameters including Hz prebake process were used. The growth conditions were varied to investigate their effects on the interface abruptness of doping profile, the film growth rates and crystalline properties. The crystallinity of the undoped silicon was excellent at the growth temperature of 900℃. The doping profiles were measured by SIMS technique. The abruptness of doping profile would be controlled within about 200A /decade in the structure of undoped Si / n^+ -Si substrate.

다공질 실리콘 산화법을 이용한 MMIC 기판의 제조 및 그 특성

김기완,권오준,이종현,이정희,김경재,이재승,최현철 한국센서학회 1999 센서학회지 Vol.8 No.2

Microstrip line was fabricated on the oxidized porous silicon layer which has nearly electrically and chemically identical properties with thermally oxidized silicon layer. Thick oxidized porous silicon layer of few tenth of micrometers was prepared by thermal oxidation of porous silicon layer on silicon substrate. Multi-step thermal oxidation process warm used obtain high quality arid thick oxidised silicon layer and to release thermal stress. Microstrip line warm fabricated on the oxidized porous silicon layer. Its microwave characteristics were measured and the availability for MMIC substrate was investigated.

HVOF 용사법으로 제조된 TiC-Fe 합금 코팅층의 내마모 특성에 미치는 열처리 영향

김문철,박찬경,진현우,김현민,최상준,권순주 대한금속재료학회(대한금속학회) 2000 대한금속·재료학회지 Vol.38 No.1

The physical soundness, microhardness and wear properties of the thermally sprayed TiC-Fe wear-resistant coatings have been investigated. Thermally sprayed coatings were fabricated by HVOF and the subsequent heat-treatments were carried out at temperatures ranging from 800℃ to 1000℃ in either vacuum or air for 30 minutes. The wear resistance of the as-sprayed TiC-Fe alloy coatings was found to be better than that of Cr₃C₂-NiCr alloy coatings and similar to that of WC-Co coatings. In addition, the wear resistance and hardness of the coating were improved by the following heat-treatment in vacuum(∼10^(-3)torr). The maximum improvement in wear resistance and microhardness was about 20 and 30%, respectively by the heat-treatment performed at 900℃ in vacuum, while the heat-treatment in air deteriorated the wear property due to oxidation. It has been revealed, from TEM and Mo¨ssbauer studies, that the improved wear resistance in the heat treated coating was mainly caused by the hardness increase associated with martensitic transformation. However, no improvement in the wear resistance of the TiC-Fe coatings heat-treated in air seemed to be caused by the residual stress due to the oxidation of Fe matrix.

무가압 침투법에 의해 제조된 Al/BN 복합재료의 미세조직과 인장성질

조수연,이건배,심호섭,허성우,유황룡,권훈 대한금속재료학회(대한금속학회) 2000 대한금속·재료학회지 Vol.38 No.12

Spontaneous infiltration and strengthening behaviors were analyzed in terms of microstructures and tensile properties of Al/BN composite fabricated by pressureless infiltration technique, compared with control alloy without BN fabricated by the same method. The Mg₃N₂ formed by the reaction of Mg vapor and nitrogen gas, which coated the particles in the powder bed, is believed to induce spontaneous infiltration through a great enhancement of wetting via the following reaction, Mg₃N₂+ 2Al→2AlN + 3Mg. This was identified by the finding of AlN particle layers on the surfaces of old Al particles in the powder bed, which contacted with the infiltrating melt. In addition, unreacted Mg₃N₂ was observed outside the composite, where the Al melt directly did not come into contact. Fine AlN particles formed in-situ resulted in a significant strengthening even in the control alloy with no addition of BN. In the composite reinforced with BN, additional AlN was formed by the interfacial reaction of the BN and Al melt as well as AlN by the in-situ reaction. Consequently, both the BN particles and the additional AlN particles formed by the interfacial reaction led to a further strengthening in the composite, as compared to control alloy strengthened by the AlN particles formed in-situ.

실리콘고무의 가교제 변화에 의한 유전특성

권병휘,이성일,홍진웅,이준웅,이원재 한국고무학회 1987 엘라스토머 및 콤포지트 Vol.22 No.1

The characteristic of the dielectric relaxation in silicone rubbers were studied in the frequency range of 1×10²∼3×10^6 ㎐ at the temperature range of 30℃∼170℃. As the results of the study, it has been confirmed that the silicone rubber containing the cross-linking agents of 2,5-bis(tert-butylperoxy)-2,5-dimethyl hexane exhibit the dissipation spectra of two kind(α, β dissipation) due to the siloxane and methyl groups. Particularly, the maximum value of dielectric loss spectra of silicone rubber combinning the cross-linking agents of 0.7phr to 1.0phr are on the increasing in high frequency region, but the specimen of above 1.0phr become smaller again The energy and the entropy of activation on the molicular motion obtained 18.32㎉/mole and 1.48㎈/mole·deg in measuring condition respectively.

교류-직류 변환오차 자동 측정시스템

권성원,박영태,조용명,강전홍,김규태 한국센서학회 1998 센서학회지 Vol.7 No.6

A dual-channel automatic ac-do voltage transfer error measurement system in which the output voltages of two thermal voltage converters which are ac voltage standard are directly measured at the same time to reduce the output voltage drift is described. Forward-reverse measurement method by using a two-channel scanner is used to cancel the offset voltage of the voltmeters. The agreements of the 4-V TVC comparison results between other national standards institute and Korea Research Institute of Standards and Science were less than about ±2 ppm in the frequency range of 40 Hz∼100 kHz, and were less than about ±4 ppm at 200 kHz∼1 MHz. Measurement uncertainty is reduced significantly from ?5 ppm of manual system to ±3 ppm of new system(up to 100 kHz) typically and great increase in comparison efficiency has been achieved by this system.