비육중인 HOLSTEIN 수소에 있어서 저질 조사료의 에너지 이용성에 관한 연구

한인규,김홍대,하종규,김완영,Yanglian, Feng 한국영양사료학회 1999 韓國營養飼料學會誌 Vol.23 No.5

본 연구는 저질 조사료의 에너지 가치 및 이용성을 평가하기 위해서 평균체중이 400㎏인 비육중인 Holstein 수소 4두를 공시하여 수행하였다. 공시동물은 각각 호흡대사실에서 4가지 사료를 4×4 Latin square 방법으로 공급받았다. 대조구는 농후사료(50%)와 Chinese wildrye hay(50%) 사료를 사용하였으며, 처리구는 저질 조사료구로서 무처리 볏짚(100%). 요소처리 볏짚(100%) 및 Chinese wildrye 건초(100%) 등 3가지 사료를 이용하였다. 처리구간의 에너지소화율에 있어서는 유의적 차이가 나타나지 알았지만, 대조구는 처리구에 비하여 에너지소화율이 유의적으로 높게 나타났다(P<0.05). Chinese wildrye 건초만을 에너지 섭취수준을 달리하여 급여한 결과, 에너지섭취가 증가할수록 에너지소화율은 감소하였다. 또한 같은 시험에서, 조사료 입자가 감소할수록 에너지소화율이 증가하는 경향을 보였다. 메탄과 뇨를 통한 에너지 손실에 있어서 처리구 및 대조구간에 차이는 없었지만, 사료중의 NDF가 증가할수록 메탄생성이 증가하였다. 요소처리 볏짚과 Chinese wildrye 건초 처리구간에 K_m과 K_f 모두 비슷하였으며, 대조구의 K_f가 가장 높게 나타났다. 단백질과 지방의 체내축적은 대조구, Chinese wildrye 건초구, 요소처리 볏짚구 및 무처리 볏짚구 순으로 높았다(P<0.05). 본 연구 결과는 화학처리 볏짚이 에너지소화율과 이용성에 면에서 무처리 볏짚보다 우수하게 나타났으며, 특히 값비싼 Chinese wildrye 건초를 에너지 이용성 면에서 값싼 화학처리 볏짚으로 대체할 수 있는 가능성을 보였다. Four steers weighing average of around 400㎏ were used in a 4 × 4 Latin square design to study energy values of low quality roughages. The energy digestibilities of rice straw, treated rice straw, and Chinese wildrye hay were not significantly different. However, the digestibility of control diet (concentrate + Chinese wildrye hay) was significantly higher (P<0.05) than those of low-quality roughages. The energy digestibility of rice straw was not improved due to the treatment of urea-Ca(OH)₂. The result showed N digestibility tended to be higher in the steer fed treated rice straw. When effects of particle sizes of low quality roughage, Chinese wildrye hay, on energy digestibility were determined, there were no significant differences in GE intakes among the treatments of four particle sizes of the hay. Results also showed that energy digestibility tended to slightly increase as the particle size reduced. Methane production in relation to DE was the highest in the treatment of untreated rice straw, and the lowest with control diet. However, there were no significant differences among four feeding treatments. Urine excretion showed similar trends with methane production. Total energy loss via methane and urine against DE were 12.26, 22.93, 16.35, and 14.88 % in control diet, untreated rice straw, treated rice straw, and Chinese wildrye hay, respectively. The efficiency of utilization of DE was not significantly different among the treatments, but untreated rice straw showed the lowest efficiency. The results also showed that K_m, among untreated rice straw, treated rice straw, and wildrye hay were similar. These data also showed that both the K_m, and K_f from treated rice straw and Chinese wildrye hay were remarkably similar. This similarity clearly showed that treated rice straw had no effect on the efficiency of ME utilization for either K_m and K_f in fattening steers. The K_f of control diet was the highest among the treatment. With regard to body deposition of protein and fat, the results showed the higher values in the order of control diet, Chinese wildrye hay, treated rice straw, and rice straw. Based on these observations, this study regarding energy utilization clearly shows that a portion of expensive forages in the diet could be replaced with low-quality roughages such as treated rice straw.

급성췌장염에 의한 췌장가성남종에서 내시경적 배액술후 발생한 췌장가성남종과 십이지장 및 대장에 발생한 내부 췌장루 1예

김연수,이문성,김진오,조영덕,이영홍,봉형근,조주영,이준성,심찬섭,황성규,전기원,변재호,장재영 대한소화기학회 1996 대한소화기학회지 Vol.28 No.1

초기설치비를 고려한 의존적 k-out-of-n:G 시스템의 보전정책 결정

신현재,조성훈,안동규,성혁제 한국산업안전학회 1999 한국안전학회지 Vol.14 No.2

In estimating the system reliability, most widely used method is to estimate the systems reliability from components reliability. In this case, it assumes that components failure is mutually independent, but it may not true in real systems. In this study, the mean cost per unit time is computed as the ratio of mean life to the mean cost. The mean life is obtained by the reliability function under power rule model. The mean cost is obtained by the mathematical model based on the inspection interval. A heuristic method is proposed to determine the optimal number of redundant units and the optimal inspection interval to minimize the mean cost per unit time. The assumptions of this study are as following : First, in the load-sharing k-out-of-n:G system, total loads are applied to the system and shared by the operating components. Secondly, the number of failed components affects the failure rate of surviving components as a function of the total load applied. Finally, the relation between the load and the failure rate of surviving components is set by the power rule model. For the practical application of the above methods, numerical examples are presented.

스펙트럼 분석기(分析器)의 VCO 설계에 관한 연구

차균현,사공석진,최한규 고려대학교 공학기술연구소 1984 고려대학교 생산기술연구소 생기연논문집 Vol.19 No.1

A VCO (Voltage Controlled Oscillator) in the spectrum analyzer is to sweep frequency in order to scan spectra of input signal. The stability and accuracy of the spectrum analyzer depend on the frequency stability and accuracy of its VCO. Both stability and accuracy can be improved by phase locking. It was implemented using the method of modulo PLL with fast acquisition time and many channel to design the VCO which can be applied to spectrum analyzer. The system is simpler than previous modulo PLL because it shows the same result with variable N/2 and constant K.

EPDM/PP/Ionomer 삼원 블렌드로 된 열가소성 가황체의 파괴 인성

김영규,조원제,하창식,고진환 한국고무학회 1996 엘라스토머 및 콤포지트 Vol.31 No.5

The fracture mechanics investigation of the thermoplastic vulcanizates(TPV) from EPDM and PP/Ionomer ternary blends was performed in terms of the J-integral by measuring fracture energy via the locus method. The TPV from ternary blends consisting of EPDM, PP and ionomer were prepared in a laboratory integral mixer by blending and vulcanizing simultaneously. Vulcanization was performed with dicumyl peroxide (DCP) and the composition of EPDM and PP was fixed at 50/50 by weight. Two kinds of polyethylene-co-methacrylic acid)(EMA) Ionomers were used. The J-integral values at crack initiation, Jc, of the dynamically vulcanized EPDM and PP/EMA Ionomer ternary blends were affected by the cavion types (Na^+ or Zn^(2+)) and contents(5-20wt%) of the added EMA Ionomers. The ternary blend containing 20wt% zinc-neutralized EMA ionomer and 1.0phr DCP showed the highest Jc values of the blends.

부생 인산석고(燐酸石膏)에 관한 연구

최한석,김광열 고려대학교 공학기술연구소 1976 고려대학교 생산기술연구소 연구보고 Vol.8 No.1

This study is to make high strength calcined gypsum from by-produced phosphogypsum of wet phosphoric acid process. By-produced phosphogypsum was autoclaved under various vapor pressures and stirring rates. Results of the present experiment are followings: a) Optimum conditions for good wet tensile-strength to autoclaving sample only are 0.5-3 hr, treatment under 1㎏/㎠ pressure. b) Optimum conditions for good wet tensile-strength to autoclaving sample-water slurry are 0.5-4 hr. treatment under l ㎏/㎠ pressure. c) In case of autoclaving sarnple added reagents optimum conditions are 1 hr. under ㎏/㎠ pressure with 90 ml of 0.5-1.0% Al₂ (SO₄)₃ solution and 23 hr. under ㎏/㎠ with 30 ml of 0. 1 N NaOH solution. d) Wet-tensile strengths of calcined phosphogypsum prepared by those described conditions are higher than K.S. special grade value and normal consistencies meet to K.S. value, but setting times are faster than K.S. value. e) Desirable crystal forms of calcined phosphogypsums with high strength are rod-like and board-like forms.

양극수소 충전이 Al 8092 합금의 파괴특성에 미치는 영향

김상식,장우길,신광선 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.11

Effects of cathodic hydrogen charging on fracture behavior of Al 8090 alloy were examined as functions of charging time, displacement rate, aging condition, applied potential and specimen orientations. Fatigue precracked SEN(single edge notch) specimens with various orientations were cathodically hydrogen charged in 0.1N HCl solution for 12 to 48 hours at an applied potential of -1800 and -2000mV vs. SCE, respectively. It was found that the cathodic hydrogen charging substantially reduced the initial fracture toughness value, K_(th), of Al 8090, while the reduction in K_(th) value was linearly proportional to (charging time)½. The dominant fracture mode of Al 8090 was intergranular dimpled rupture, and the plasticity around the dimples on the intergranular facets appeared to be reduced with hydrogen charging. The sensitivity to hydrogen assisted fracture of Al 8090 was greatly affected by specimen orientation, applied potential and aging condition. Like other high-strength Al alloys, the resistance to hydrogen assisted fracture was increased with increasing aging time. The reason for the improved resistance with prolonged aging in Al 8090 is believed to be related to the precipitate free zone formed along the grain boundaries.

슬래그중 고체철의 산화거동에 관한 속도론적 고찰

백종문,이홍기,고정호,민동준 대한금속재료학회(대한금속학회) 1998 대한금속·재료학회지 Vol.36 No.12

The kinetic experiments have been made on iron oxidation in slag by oxidizing gases at 1387∼1500℃. The effect of temperature, FeO content and oxygen potential of gas on the reaction rate have been examined. The iron oxidizing rate is considerably increased with increasing temperature and FeO content in slag. It was also found that the rate controlling step of reaction have been depended on the temperature, FeO content in slag and (P_(co₂)/P_(co) as an oxygen potential at gas/slag interface. The dependence of the overall reaction rate constant on temperature and initial FeO content in slag at 1450℃ could be expressed as follows; log k_(overall) = -0.36-10,820/T[㏖/㎠·sec·atm] k_(overall) = 1.04×10^(-7)(wt%FeO)^(0.75)[㏖/㎠·sec·atm] In condition of high oxygen potential such as high FeO content and (P_(co₂)/P_(co)), the chemical reaction at interface between slag and gas might play a important role as a rate controlling step of overall reaction, which is controlled by the dissociation of CO₂ at slag/gas interface. But in case of low (P_(co₂)/P_(co)), mass transfer and chemical reaction at interface between slag and iron become important as a rate controlling step. The reaction mechanism of iron oxidization in slag by gas have been discussed in terms of rate constant for elementary reactions.

극한조건하 강구조 부재 이음부의 파괴거동해석

김두환,한석규,안세희 한국산업안전학회 1998 한국안전학회지 Vol.13 No.4

Welding structures will be occurred sudden crack or failure by reduced fracture toughness in case of low temperature. To protect these unstable fracture is very important. Because fracture of welding part come from welding faults or residual stress, critical stress intensity factors are acquired at temperatures between 22℃ and -70℃ from base metal, welding metal and H.A.Z. It was studied effectiveness of annealing and affection of residual stress under low temperatures. In case of fracture toughness test, it showed that fracture toughness value decreased, according to the decrease of temperature. Expecially In case that compressive residual stress was existed, K_c increased.

방사성 의약품 합성에 관한 연구(Ⅵ) : Auflatoxine-B1의 방사성 요오드 표지와 그 생리작용

박경배,유용운,성호경,김유선 대한핵의학회 1978 핵의학 분자영상 Vol.12 No.1

Carcinogen으로 알려져 있는 auflatoxine계통 화합물의 방사성 표지 반응을 연구하였다. Auflatoxine 계통 약품중에서 그 함유량이 가장 큰 auflatoxin-B1을 초산 촉매하에 chloroamine-T를 사용하여 125I로 표지한 결과 표지화합물을 방사화학적 수율 63.6%로 얻을 수 있었다. 생성물의 화학구조를 I.R. 및 N.M.R.로 검사한 결과 auflatoxine의 benzene고리에 표지되었음을 확인하였다. 쥐를 시험동물로 삼아 경구 투여후의 대사과정을 부검으로 조사한 결과 간 및 혈액에 방사능이 축적되고 요오드이온은 분리되지 않았음을 확인하였다. Labelling auflatoxines, the potential carcinogenic compounds, by radioactive iodine has been studied. The aufiatoxine-B1, which is known to be the most abundant components of auflatoxines in the nature, was labelled by radioactive iodine-125 through an acid catalyst chloroamine-T procedure. The radiochemical yield was amounted to 63.6%. The chemical structure of the labelled product was proved to be 6-iodo 5-methoxy coumarine structure of auflatoxine-B1 molecule by means of I.R. and N.M.R. spectroscopy. The labelled product was orally administered in a test animal (Rat) and examined the accumnulation of radioactivity in the body at the definite time interval. The accumnulation of the radioactivity was pronounced at the blood and the liver. There was no indication of the decomposition of auflatcxine-B1-125I in the organs of the test animal. $quot;