• Journal of Mechanical Science and Technology
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• 제20권4호
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• pp.473-481
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• 2006

Predicting fatigue life by numerical methods was almost impossible in the field of rubber materials. One of the reasons is that there is not obvious fracture criteria caused by nonstandardization of material and excessively various way of mixing process. But, tearing energy as fracture factor can be applied to a rubber-like material regardless of different types of fillers, relative to other fracture factors and the crack growth process of rubber could be considered as the whole fatigue failure process by the existence of potential defects in industrial rubber components. This characteristic of fatigue failure could make it possible to predict the fatigue life of rubber components in theoretical way. FESEM photographs of the surface of industrial rubber components were analyzed for verifying the existence and distribution of potential defects. For the prediction of fatigue life, theoretical way of evaluating tearing energy for the general shape of test-piece was proposed. Also, algebraic expression for the prediction of fatigue life was derived from the rough cut growth rate equation and verified by comparing with experimental fatigue lives of dumbbell fatigue specimen in various loading condition.

• Asian-Australasian Journal of Animal Sciences
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• 제18권12호
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• pp.1775-1779
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• 2005

Seventy-two crossbred gilts of approximately 33 kg initial weight were used in this study. The gilts were randomly assigned into three groups. The three dietary treatments were basal diet only (control group), basal diet+10 mg/kg lead, and basal diet+10 mg/kg lead+0.5% particulate montmorillonite (PM). The results showed that the addition of lead to the diet decreased significantly the body weight and feed efficiency, but PM could restore body weight and feed efficiency of gilts compared to the Pb exposure group. There were no significant differences in weights of ovaries and uteri with addition of either lead or PM to the diet. Supplementing the lead in the diet of gilts also significantly increased the concentration of lead in blood, decreased circulating lutenizing hormone (LH) and estradiol (E$_2$) levels in serum, the addition of PM to the diet effectively adsorbed and lowered lead concentration in the blood. These data suggested that lead disrupts the signals between the hypothalamus and pituitary gland in gilts, and possibly suppressed the secretion of relative growth hormone and sex hormone. On the other hand, PM may ameliorate Pb toxicity in pigs.

• 한국결정성장학회지
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• 제7권4호
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• pp.610-618
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• 1997

반응용침법으로 제조된 $Al_2O_3$/Al 복합재료는 900-$1200^{\circ}C$의 온도범위에서 $Al_2O_3$ 분말성형체에 용융Al을 침투시켜 제조하였다. 용융침투는 각 온도에서 잠복기를 거친후 발생하였으며, 복합재료의 성장속도는 시간에 따라 선형적으로 비례하였다. 제조된 복합재료의 주성분은 $Al_2$O$_3$와 Al이었고 소량의 Si이 탐지되었다. 복합재료의 상대밀도는 $Al_2O_3$ 입자크기가 증가함에 따라 증가하였고 용융 침투온도가 높을수록 감소하였다.

• 한국결정성장학회지
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• 제7권4호
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• pp.632-639
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• 1997

단일상으로서는 치밀한 소결이 힘든 TiC 와 $TiB_2$ 혼합조성을 상압소결하여 얻어진 TiC-$TiB_2$ 고온복합체의 소결밀도와 미세구조를 연구하였다. 소성조제의 임계첨가량은 1 wt% Fe 및 3 wt% Ni으로 최대 소결밀도는 약 95%이었다. TiC-$TiB_2$ 복합체의 미세구조에서 TiC상은 matrix로서 $TiB_2$입자성장을 저지하였고, wave 흑은 계단식 상계면의 존재는 석출된 Ni-rich phases가 소결중 액상으로 존재하다가 냉각시 고화한 것으로 TEM분석결과 확인할 수 있었다. 또한, 이들 Ni-rich phases는 matrix grain안에서 dislocation형성 요인으로 작용하고 있음이 확인되었다.

• 한국작물학회지
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• 제50권5호
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• pp.332-335
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• 2005

The three Korean wheat cultivars with different plant types; the erect, the middle and the creeping growth habit, were studied for their utilization to solar radiation, temperature changes on the furrow and to provide optimum planting space for producing the high yield in 2003. The average solar radiation rate was lowest for creeping type ($39.2\%$) and highest for erect type ($75.8\%$) The correlation coefficient between the coverage rate and the solar transmission rate was r = 0.8624 which was significant at $5\%$ level. The relative growth of the plant, tiller rate and leaf size was increased in the erect and the middle type at lower plant density, while no change on plant growth at creeping type regardless of plant density. The increase of leaf size in the lower plant density was due to longer flag and the first leaf than those of other plant types. The temperature on the furrow of growing plants was changed by the canopy. The changes in temperature pattern on the furrow according to plant types during winter season was different compared to the non plant ground. The temperature of the nonplant ground was the lowest due to solar reduction increasing the amount of cool air flowing in the furrow.

• 유통과학연구
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• 제16권6호
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• pp.37-53
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• 2018

Purpose - There have been not enough studies on the ways customer Moment of Truth(MOT) activities are structured along with consumption chain and their influences as well as the relative influences of service quality at Moment of Truth on customer performance. Therefore, customer service needs needed at Moment of Truth may differ depending on whether these distribution services are at introduction-growth stages or maturity-decline stage already, but there is no study which illustrates this. Research design, data, and methodology - This study selects VoIP and IPTV as the household telecommunication and distribution services at introduction-growth stages as well as high speed internet and wire telephone as those at maturity-decline stages. Then it identifies which experiences that customers have at Moment of Truth by each service as well as the influences related to what the customers consider as important. Results - As the result of demonstration with the target of 858 respondents, customers' experiences and requests differ at Moment of Truth. For service quality, what takes the positive roles in customer performance includes corporeality and certainty for the services at introduction-growth stages as well as reliability, sympathy, and mutuality for those at maturity-decline stages. Conclusions - Implications of these results as well as further directions for study are suggested.

• 한국미생물·생명공학회지
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• 제22권4호
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• pp.423-429
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• 1994

A bacterial strain which formed a distinct colony on agar plate containing naphthalene as a vapor phase and grew well ina liquid minimal medium was isolated and identified as Alcaligenes sp. A111. Optimum temperature and pH for the cultivation of Alcaligenes sp. A111 were 30$\cir$C and 7.0, respectively. Cell growth increased dramatically from 12 hours after inoculation and revealed a stationary phase at about 48 hours. Relative growth rate ($\mu$')increased hyperbolically depending on the conceration of naphthalene up to 500 ppm and reached to the maximum value pf 2.8/day, but $\mu$' didn't change within a range of 500~4000 ppm naphthalene. NH$_{4}$Cl or NH$_{4}$NO$_{3}$ was preferrd as a nitrogen source and a P : N ratio by weight og 6 : 1 was favorable to cell growth. Alcaligenes sp. A111 utilized the intermediates of degradation of naphthalene and showed tolerance to benzene, toluene, and octane. therefore, it is suggested that Alcaligenes sp. A111 could be effectively used for the biological treatment of wastewater containing naphthalene in the presence of some aromatic compounds.

• The Korean Journal of Ecology
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• 제11권2호
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• pp.55-64
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• 1988

The seasonal pattern of pool size and withdrawal from senescing or stroage organ, and the annual magintude of internal-and plant-soil cycles for nitrogen and phosphorus in a Glyceria leptolepis Ohwi population in a marsh of the Mt. Geumoh were investigared. The population pool changed from initial size of 6.8 to the maximum of 16.1gN$m^{-2}$ for N and from 1.7 to 3.9g Pm$m^{-2}$ for P, maintaining far higher relative pool size during the first half of the growth period as compared with that for biomass. A sharp increase in N and P pool was noticed in early spring before the biomass growth was recognized, The major process supplying the demand for N and P changed as the growth progressed showing the order; absorption-withdrwal-absorption-with-drawal. The annual magnitude of plant-soil cycle for N and P was 18.0-19.1 and 2.9-3.3gm$m^{-2}$, accounting for 3 and 5% of each nutrient pool in 0-20 cm humus layer, respectively. The higher exent of internal cycle and the lower rate of annual turnover for P(1.08) as compared with those for N may suggest that this population conserves and reuses P more efficiently than N.

• 한국토양비료학회지
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• 제22권2호
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• pp.127-130
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• 1989

Perlite에 묘삼을 심고 14일간 여러농도의 $CO_2$를 근권에 처리하고 인삼의 생육상태를 조사하였다. 6~8%에서 완전 출아소요 일수가 3일간 단축 되었으며 13%이상에서 출아가 지연되었다. 14일처리후 경장은 $CO_2$농도가 높을수록 적었다. 64일후의 생육량의 증가율은 8%를 장점으로 증가한 후 감소하는 경향을 보였으나 유의성은 없었다. 22%의 64일간 처리는 65% 출아 되었으나 경장은 60% 감소되었고 35%의 처리는 모두 면삼(眠蔘)이 되었다. 이상의 결과는 인삼의 생육조절 및 저장에 $CO_2$가 활용될 수 있음을 시사한다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제11권2호
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• pp.164-167
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• 2006

The influence of temperature and agitation on the growth of Escherichia coli expressing hepatitis B core antigen (HBcAg) in stirred tank bioreactor were investigated. The highest specific growth rate for E. coli$(0.844 h^{-1})$ was achieved at a temperature of $37^{\circ}C$ and an agitation speed of 250 rpm. The activation energy for the growth of the E. coli strain W3110lQ in the stirred tank bioreactor was estimated to be 11 kcal/mol. The highest protein yield was achieved at a temperature of $44^{\circ}C$ and an agitation speed of 250 rpm. The relative protein concentration at $44^{\circ}C$ is 30 and 6% higher compared to that at 30 and $37^{\circ}C$, respectively.