에폭시 수지의 경화 거동에 미치는 반응성 희석제의 영향

김완영,이대수,김형순,김정기 ( Wan Young Kim,Dai Soo Lee,Hyung Soon Kim,Jung Gee Kim ) 한국공업화학회 1994 공업화학 Vol.5 No.6

에폭시 수지의 성형 가공성을 조절하기 위해 반응성 희석제를 사용했을 때의 경화특성 및 경화 후 유리 전이온도의 변화를 조사하였다. 반응성 희석제로 사용한 Butyl gilcidyl ether(BGE) 및 Phenyl glycidyl ether(PGE)함량의 증가에 따라 경화에 따른 발열량과 경화 후 유리 전이온도는 낮아지는 특성이 관찰되었다. 에폭시 수지는 BGE를 사용한 경우 PGE를 사용한 경우보다 더 낮은 유리 전이온도를 보였으며, 희석제의 첨가에 따른 유리 전이온도 변화는 가교점 사이의 분자량 증가 때문으로 해석하였다. 에폭시 수지의 경화 거동을 자촉매 반응에 대한 속도론식으로 해석한 결과 속도상수 k₁, k₂는 희석제의 양에 따라 감소하였다. Curing behavior and glass transition temperatures of epoxy resins into which reactive diluents were added to control processability were investigated. Heat of cure generated of the epoxy resin was reduced with butyl glycidyl ether(BGE) and phenyl glycidyl ether(PGE) contents. T_g of the resin was decreased with the amount of reactive diluents and it was attributed to increased molecular weight between crosslink points. Cure kinetics of the resins was studied employing autocatalytic reaction model and found that reaction constants decreased as the contents of reactive diluent was increased.

황 및 가황 촉진제의 함량에 따른 NR / BR 블렌드의 가황과 물리적 , 기계적 특성의 변화

김완영,이대수,김윤섭,김형순,라창운 ( Wan Young Kim,Dai Soo Lee,Youn Sop Kim,Hyung Soon Kim,Chang Woon Nah ) 한국공업화학회 1991 공업화학 Vol.2 No.4

가황계에 따른 NR/BR 블렌드의 물리적 · 기계적 특성의 변화를 가교밀도의 차이로 해석하였다. 경화제의 비율 및 함량이 증가함에 따라 가황속도 및 최대 토오크는 증가를 보였으며, 가교밀도도 증가하였다. 가교밀도의 증가에 따라 경도, 300% 모듈러스, 반발탄성 및 마모특성은 증가를 보인 반면에 발열에 의한 온도 상승 및 60 ℃ 에서의 tan δ는 감소를 보였다. 따라서 높은 하중이 가해지는 트럭/버스 타이어의 트레드 부위에 사용하는 경우 회전저항이 적은 semi-EV 가황계가 가장 적절한 가황 시스템으로 판단되었다. The physico-mechanical properties of NR/BR blend were measured, and the results were interpreted in terms of the crosslink density with cure system. The cure rate, maximum torque and crosslink density increase with the content and ratio of curative for cure system. Hardness, 300% tensile modulus, rebound and wear resistance increase with crosslink density of the vulcanizate but heat build-up and tan δat 60 ℃ decrease. It is expected that semi-EV(efficient vulcanization) cure system is appropriate for application in tire tread of truck/bus in which load bearing property is impotant.

Hexamethoxymethylmelamine 이 고무 - 황동피복코드간의 접착에 미치는 영향

김완영,김윤섭,육경창,김형순,이정용,최상원 ( Wan Young Kim,Youn Sop Kim,Gyeong Chang Yug,Hyung Soon Kim,Jeong Yong Lee,Sang Won Choi ) 한국공업화학회 1992 공업화학 Vol.3 No.3

본 연구는 고무와 황동피복 코드간의 접착력 향상을 위하여 사용되는 resorcinol formaldehyde(RF) resin과 hexamethoxymethylmelamine(HMMM)이 고무 컴파운드내에서 나타내는 morphology와 접착특성에 대하여 고찰하였다. 가황후 resin은 구형의 형태로 시편 전체에 고르게 분포되어 있었고 그의 입경은 약 2000Å정도였다. 코드와 함께 가황시킨 시편에서 코드 주위에 존재하는 resin함락이 감소한 것으로 보아 resin이 코드쪽으로 이동이 있었던 것으로 생각된다. 또한 모듈러스는 methylene donor인 HMMM의 양이 많을수록 증가하였으며, 접착층이 더 두껍게 형성되었다. 접착력은 열노화에 의하여 상실되며 이는 대부분 초기에 발생함을 알 수 있었다. 접착컴파운드에서 가장 유리한 RF resin과 HMMM의 비는 물성, 접착층의 안정성, 열노화특성 등을 고려할 때 1 : 0.9이었다. The morphology and adhesion properties of rubber compounds containing resorcinol formaldehyde(RF) resin and hexamethoxymethylmelamine (HMMM) used in adhesion of rubber to brass-plated steel cord was investigated. The resins were spherical particles about 2000Å diameter and distributed in rubber compounds homogeneously, and the cured compound with steel cord showed migration of resin to steel cord. Also, modulus was increased with increasing HMMM contents. The loss of adhesion between rubber and steel cord was likely to be at initial stages by thermal aging. Considering the physical properties, stability of adhesion layer and thermal aging property, optimum ratio of RF resin and HMMM was 1 : 0.9.

비타민 A와 D의 공급제한이 거세 한우의 육질등급에 미치는 영향

김완영,박진기,조성용,남기택,여준모,Kim, W.Y.,Park, J.K.,Cho, S.Y.,Nam, K.T.,Yeo, J.M. 국립한국농수산대학교 교육개발센터 2016 현장농업연구지 = Journal of practical agricultural resear Vol.18 No.1

Sixty Hanwoo steers(15 months of age; 409±29.2 kg of BW) were used to evaluate the effects of dietary vitamins A and D restriction on carcass characteristics. Steers were allotted randomly to 1 of 4 treatments: Control(diet supplemented with vitamins A, D and E), -A (diet supplemented with vitamins D and E), -D(diet supplemented with vitamins A and E) and -AD(diet supplemented with vitamin E only). Steers were fed the experimental diet for a period of 8 months(until 23 months of age), and then supplemented with vitamins A and D at 0.05% of the diet(as fed-basis) from 24 to 26 months of age, and at 0.1% of the diet from 27 to 31 months of age(harvesting time). Dietary restriction of vitamins A and D did not affect DM intake, daily gain and feed conversion ratio. But the concentration of serum retinol was significantly(P<0.05) decreased by vitamin A restriction with the lowest concentration being seen at 23 months of age(345.0 ㎍/L and 326.7㎍/L for control and -D treatment versus 169.3 ㎍/L and 175.4 ㎍/L for -A and -AD treatments). The serum concentration of 25(OH)D₃ was also decreased significantly(P<0.05) by vitamin D restriction and the lowest concentration was seen at 18 months of age(53.7ng/ml and 61.8ng/ml for control and - A treatment versus 24.0 ng/ml and 24.5 ng/ml for -D and -AD treatments). After the restriction period of vitamins A and D, the concentrations of retinol and 25(OH)D₃ for - A, -D and -AD treatments were recovered at those of control. Dietary restriction of vitamins A and D did not affect carcass weight, backfat thickness, ribeye area, quality grade and yield grade. But marbling score was significantly increased by vitamin A restriction compared with control(6.73, 6.87 and 5.73 for -A, -AD and control, respectively). The results of the present study suggested that dietary vitamin A restriction could improve marbling score in Hanwoo steers.

반추가축에 있어서 옥수수 알곡의 가공이 영양소 이용에 미치는 영향에 관한 고찰

김완영,김홍욱,이기종,Kim, W.Y.,Kim, H.W.,Lee, K.J. 국립한국농수산대학교 교육개발센터 2001 현장농업연구지 = Journal of practical agricultural resear Vol.3 No.1

Through out the last few decades, processing methods for ingredients of feed grains, such as grinding, flaking, extrusion, soaking, cracking etc., have been adopted in order to improve the nutrient digestibility in ruminants. Among feed grains, processing methods for whole corns have been the most frequently studied since corns are utilized as the thumb ingredients in formulating feeds. In these days, flaking of whole corns is the most incessantly used in formulation feeds, resulting in enhancing the performance of ruminants. Recently formulating non-forage feed for beef cattle, especially Holsteins, without processing whole corns is carrying out through various feed companies with expectations of whole corns acting like forages. However, it can not be ruled out that whole corns might possibly result in decreasing the productivity due to the depression of nutrient utilizations. Therefore, one must reevaluate the non-forage feeds as well as makes an effort to develop the rational and effective methodology in processing whole corns with the consideration of rumen eco-system.

옥수수 알곡의 가공처리에 의한 영양소 이용성 향상에 관한 연구 II. 한우에 있어서 옥수수 알곡의 가공처리가 반추위 미생물의 부착양상에 미치는 영향

김완영,김홍욱,강충민,Kim, W.Y.,Kim, H.W.,Kang, C.M. 국립한국농수산대학교 교육개발센터 2001 현장농업연구지 = Journal of practical agricultural resear Vol.3 No.1

This study was conducted to determine effects of whole and processed corns on attachment characteristics of rumen microbes in Hanwoo. Whole corn(WC) was processed into four different types; ground corn(GC), cracked corn(CC), flaked corn(FC), and soaked corn(SC). After each processed corns was incubated in the rumen of Hanwoo for 12 h and 24 h, attachment characteristics of rumen microbes and morphological changes of feed substrates was examined by utilizing scanning electron microscopy(SEM). In this study, the treatment group of GC and CC showed the highest in the attachment of rumen microbes. On the other hand, microbial attachments to the starch particle of WC and SC were hardly detected. However, with the increase of incubation time the surface of WC and SC was covered by many microbes, resulting in enhancing the surface degradation.

셀레늄강화 버섯폐배지에 대한 사료 셀레늄공급원으로의 평가 연구

김완영,민정기,Kim, W.Y.,Min, J.K. 국립한국농수산대학교 교육개발센터 2005 현장농업연구지 = Journal of practical agricultural resear Vol.7 No.1

This study was conducted to evaluate the spent composts of selenium-enriched mushrooms as a feed selenium Source. Total selenium (Se) contents and Se profiles in the spent mushroom composts (SMC) were determined. In addtion, we also investigated the metabolism in relation to Se accumulation in the mushroom. Mushrooms used in this study were Flammulina velutipes and Se enriched mushrooms were grown for 60 days by adding 2 mg of inorganic Se (Na₂SeO₃) per kg of mushroom composts (MC) on as-fed basis and it was compared with mushrooms not to add Se to the MC. Total Se contents for Se-treated mushrooms were significantly increased (P<0.0001) by 20-fold (4.51 ㎍/g of dry) compared to Se-untreated (0.23 ㎍/g of dry). On the contrary, organic Se proportion was significantly lower (P<0.0001) in the Se-treated mushroom (72.3%) than Se-untreated (100%, not analytically detected of inorganic Se). Se distribution upon a length in the Se-treated mushrooms was the highest in the bottom part (6.86 ㎍/g of dry) near to MC, and top and middle parts were significantly lower (3.71 and 3.01 ㎍/g of dry, respectively) than the bottom (P<0.001). In the SMC from Se-treated mushrooms, a high concentration of Se (5.04 ㎍/g of dry) was still remained, but that from Se-untreated mushrooms was significantly low (P<0.0001) as 0.08 ㎍/g of dry. Se-treated SMC showed a high rate of organic Se (65.67%), suggesting that most of inorganic Se in the SMC was converted to organic Se by mushroom mycelia, and Se-untreated SMC showed 100% of organic Se, not being detected of inorganic Se. Prior to mycelia inoculation in the mushroom culture, the sterilization of MC brought approximately 18% of Se loss in the MC. This result is in accordance with facts generally known that Se is weak in the high temperature and it is consequently volatilized under that condition. Apparent and net accumulation rates (%) for Se into mushrooms were 14.81 and 10.14%, respectively and their difference (4.67%) is considered that it is due to the volatilization into the air via metabolic process of mushroom itself. From the result of this study, inorganic Se addition to MC for mushroom improved the Se content in the mushroom and SMC from Se-enriched mushrooms contained a high concentration of Se. Mycelium and fruiting body from mushrooms converted inorganic Se in MC to organic Se, indicating a high proportion of organic Se in the mushroom and SMC. Therefore, Se in Se-enriched mushroom and SMC was recognized as Se sources of food for human as well as feed for livestock.

이유 전 농후사료(무조사료) 급여가 한우 송아지의 장관발달 및 근육 성분에 미치는 영향

김완영,이성훈,김성기,이장형,노환국,황진호,이성실,여준모,Kim, W.Y.,Lee, S.H.,Kim, S.K.,Lee, J.H.,Nho, W.G.,Hwang, J.H.,Lee, S.S.,Yeo, J.M. 국립한국농수산대학교 교육개발센터 2013 현장농업연구지 = Journal of practical agricultural resear Vol.15 No.1

The present study was conducted to investigate effects of feeding concentrate on development of intestinal tract and composition of muscle in suckling Hanwoo calves before weaning(60 days of age). Twenty-four Hanwoo calves(12 heifers and 12 bulls) at six days of age were randomly assigned to one of three dietary treatments[hay and two levels(low and high) of concentrate feeding] and given each diet with free access to their dams for suckling until 60 days of age. At 60 days of age, two calves from each treatment were used for post-mortem examination of intestine development and chemical analysis of muscle. Feed intake between 31 and 60 days of age was significantly(P<0.05) higher for the high concentrate treatment(532.4g/d) than for other treatments(78.9 and 108.9g/d for hay and low concentrate treatments, respectively). Although feed intake showed a large difference between the low and high concentrate treatments, body weights at birth and 60 days of age were similar between the treatments, suggesting that calves in the low concentrate feeding were supplied more milk from their dams than those in the high concentrate feeding. The ratio of intestine weight to body weight at 60 days of age was increased in the high concentrate(3.35%), compared with those in the hay(2.93%) and low concentrate(3.03%) treatments. The chemical composition of muscle in sirloin and hind leg was not affected by the treatments. In conclusions, the results of the present study showed that feeding concentrate to Hanwoo calves before weaning might stimulate intestine development relative to feeding hay.

Cordycepin 강화 한우고기 생산에 관한 연구 II. 곡립기주 동충하초 균사체 급여가 한우고기내 cordycepin 축적에 미치는 영향

김완영,이성훈,김도형,이장형,노환국,황진호,여준모,Kim, W.Y.,Lee, S.H.,Kim, D.H.,Lee, J.H.,Nho, W.G.,Hwang, J.H.,Yeo, J.M. 국립한국농수산대학교 교육개발센터 2009 현장농업연구지 = Journal of practical agricultural resear Vol.11 No.1

The present experiment was conducted to examine the effects of mycelia of Cordyceps militaris cultured from grains on cordycepin deposition in muscles and plasma glutathione peroxidase activity in finishing Hanwoo steers. Four steers were divided into two groups. Control group received no supplement whereas treatment group received 1 % mycelia of C. militaris of their feed intake for 80 days prior to slaughtering. Final body weight, average daily gain, dry matter intake were not affected by the treatment. But the activity of plasma glutathione peroxidase was numerically higher for the treatment group than for the control group (15.70 vs 9.23 unit). Furthermore, cordycepin deposition in muscles on the treatment group was identified with thin layer chromatography. The results of the present experiment show that cordycepin could be deposited in muscles of Hanwoo beef by feeding mycelia of Cordyceps militaris cultured from grains.

댐 시설물 수중구조체 보수용 패칭재료의 적용 가능성 평가

김완영,Kim, Wan-Young 한국농공학회 2009 한국농공학회논문집 Vol.51 No.6

This study was performed to evaluate applicability of patching materials for underwater dam concrete structure. Two kinds of patching materials was investigated. Laboratory experimentals were conducted by workability, compressive strength, bond strength, chloride ion penetration, abrasion resistance. Test results showed that the most performances are relatively good except chloride ion penetration.