• 대한수학회보
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• 제23권2호
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• pp.123-132
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• 1986

Let X be a real Banach space with norm vertical bar . vertical bar and let I denote the identity operator. Then an operator A.contnd.X*X with domain D(A) and range R(A) is said to be accretive if vertical bar x$_{1}$-x$_{2}$ vertical bar.leq.vertical bar x$_{1}$-x$_{2}$+r(y$_{1}$-y$_{2}$) vertical bar for all y$_{i}$.mem.Ax$_{i}$, i=1, 2, and r>0. An accretive operator A.contnd.X*X is m-accretive if R(I+rA)=X for all r>0.r>0.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제10권2호
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• pp.119-123
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• 2010

We introduce and investigate the concepts of ($T_i,T_j$)-fuzzy $\beta$-(r, s)-open sets, ($T_i,T_j$)-fuzzy $\beta$-(r, s)-closed sets and fuzzy pairwise $\beta$-(r, s)-continuous mappings in smooth bitopological spaces.

• Journal of Mechanical Science and Technology
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• 제18권3호
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• pp.513-525
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• 2004

This paper reports an experimental study on flow boiling of pure refrigerants R l34a and R l23 and their mixtures in a uniformly heated horizontal tube. The flow pattern was observed through tubular sight glasses with an internal diameter of 10㎜ located at the inlet and outlet of the test section. Tests were run at a pressure of 0.6 MPa in the heat flux ranges of 5-50㎾/㎡, vapor quality 0-100 percent and mass velocity of 150-600㎏/㎡s. Both in the nucleate boiling-dominant region at low quality and in the two-phase convective evaporation region at higher quality where nucleation is supposed to be fully suppressed, the heat transfer coefficient for the mixture was lower than that for an equivalent pure component with the same physical properties as the mixture. The reduction of the heat transfer coefficient in mixture is explained by such mechanisms as mass transfer resistance and non-linear variation in physical properties etc. In this study, the contribution of convective evaporation, which is obtained for pure refrigerants under the suppression of nucleate boiling, is multiplied by the composition factor by Singal et al. (1984). On the basis of Chen's superposition model, a new correlation is presented for heat transfer coefficients of mixture.

• 상하수도학회지
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• 제29권1호
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• pp.123-131
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• 2015

A CCTV inspection method has been widely used to assess sewer condition and performance, but Korea lacks a proper decision support system for prioritizing sewer repair and rehabilitation (R&R). The objective of this paper is to introduce the results that we have developed in the Sewer Condition Assessment and Rehabilitation Decision-making (SCARD) Program using MS-EXCEL. The SCARD-Program is based on a standardized defect score for sewer structural and hydraulic assessment. Priorities are ranked based on risk scores, which are calculated by multiplying the sewer severity scores by the environmental impacts. This program is composed of three parts, which are decision-making for sewer condition and performance assessment, decision-making for sewer R&R priority assessment, and decision-making for optimal budget allocation. The SCARD-Program is useful for decision-makers, as it enables them to assess the sewer condition and to prioritize sewer R&R within the limited annual budget. In the future, this program logic will applied to the GIS-based sewer asset management system in local governments.

• 설비공학논문집
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• 제10권3호
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• pp.303-314
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• 1998

In this study, the performance of a multi-stage condensation heat pump was examined. Computer simulation programs were developed for 1-stage, 2-stage, and 3-stage heat pumps and R11, R123, R141b were tested as working fluids. The results showed that coefficients of performance(COPs) of an optimized 3-stage condensation heat pump are 25∼40% higher than those of a conventional 1-stage heat pump. The increase in COP, however, differed among the fluids tested. The improvement in COP largely stems from the decrease in average LMTD values in the condensers of the multi-stage system. For the 3-stage condensation heat pumps, optimized UA values of three condensers were determined to be 30∼40% of the UA value of the total condenser regardless of the working fluid. When the amount of cooling water entering into the intermediate and high-stage subcoolers is roughly 10% of the total condenser cooling water respectively, the optimum performance was achieved for the 3-stage condensation heat pump.

• International Journal of Air-Conditioning and Refrigeration
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• 제12권2호
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• pp.70-78
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• 2004

An experimental study on the pressure drop during flow boiling for pure refrigerants Rl34a and R123, and their mixture was carried out in a uniformly heated horizontal tube. Tests were run at a pressure of 0.6㎫ and in the ranges of heat flux 5-50㎾/$m^2$, vapor quality 0-100 percent and mass velocity of 150-600 kg/$m^2$s. Generally, the two-phase frictional multiplier is used to predict the frictional pressure drop during the two-phase flow boiling. The obtained results have been compared to the existing various correlations for the two-phase multiplier. Also, the frictional pressure drop was compared to a few available correlations; The Lockhart-Martinelli correlation considerally overpredicted the frictional pressure drop data for mixture as well as pure components in the entire mass velocity ranges employed in the present study, while the Chisholm correlation underpredicted the present data. The Friedel correlation was found to satisfactorily correlate the frictional pressure drop data except for a low quality region.

• 한국농림기상학회지
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• 제11권3호
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• pp.123-125
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• 2009

I thank Kang and Kim (this issue) for their interests and constructive comments on Kwon (2009) in which the objectives were to find the site-specific relationship between net radiation ($R_N$) and solar radiation ($R_S$) in major plant functional types in Korea and to examine its applicability for estimating $R_N$. The authors addressed six major points requesting clarification and suggesting improvement. Below, my replies are provided.

• 디지털산업정보학회논문지
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• 제15권1호
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• pp.123-132
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• 2019

As the one-person households with economic power have increased, the consumption culture changed as well. The primary purpose of this study is to investigate the on-line shopping motivation of one-person households in terms of consumer value. Economic value, emotional value, convenience value, social value were identified as affecting factors of satisfaction and intention to re-use of on-line shopping purchasing based on prior studies of on-line shopping behavior. This study tested the hypothesized model targeting 244 one-person households who have purchased products in on-line shopping mall. According to the results of analysis by using R, economic value, emotional value are significantly related to the consumer satisfaction but convenience value, social value are not. Consumer satisfaction of online purchasing was also shown to be related to the intention to re-use. However no difference between men and female was shown in shopping motivations. The research result can provide useful guidelines and strategies for one-person households with online shopping malls.

• 대한핵의학회지
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• 제35권5호
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• pp.324-333
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• 2001

목적: $^{123}I$ 표지된 지방산 유도체는 심근에너지대사를 평가하는데 사용되어 왔다. 본 연구는 $^{123}I$-BMIPP를 지방육종 진단물질로서의 유용성을 평가하기 위하여, 지방육종 세포주와 신경교종 세포주간의 시험관내의 섭취율을 비교하고 지방육종 형성 nude mice 동물모델에서의 생체분포와 생체영상을 확인하였다. 대상 및 방법: Cold-BMIPP에 $^{123}I$의 표지는 $Cu^{2+}$를 촉매로 이용하여 반응 후 Sep-pak으로 분리정제하여 TLC를 이용하여 방사화학적 순도를 확인하였다. 시험관내 섭취율 시험은 $^{123}I$-BMIPP를 지방육종 세포주인 SW872와 신경교종 세포주인 9L에 각각 시간대별로 5분, 15분, 30분, 60분, 120분, 180분씩 처리한 후 섭취율을 비교하였다. 정상 백서에서의 생체분포를 평가하기 위하여 18시간 금식시킨 군(n=6/군)과 식이를 한 군으로하여 $^{123}I$-BMIPP를 꼬리정맥에 주사하고 30분, 2시간, 24시간후의 각 장기별 방사능을 감마카운터로 계측하였다. 지방육종 세포주인 SW872를 왼쪽 대퇴부에 피하접종한후 종양이 형성된 누드마우스(n=5/군)를 18시간 금식시키고 $^{123}I$-BMIPP를 주사한 후 30분, 2시간, 24시간후의 생체분포와 2시간, 24시간의 생체영상을 평가하였다. 결과: $^{123}I$-BMIPP의 표지수율은 95 % 이상이었으며, 방사화학적 순도는 99 % 이상이었다. 지방육종 세포주인 SW872가 신경교종 세포주인 9L보다 180분에서 1.5배 정도의 섭취율의 증가를 나타내었다. 정상 백서에서의 생체분포를 확인한 결과, 24시간에서 금식을 한 경우가 식이를 한 경우보다 방사성표지 지방산의 제거율이 지연됨을 알 수가 있었으며 주요 배출장기는 위장관으로 확인되었다. 지방육종이 형성된 누드마우스에서 각 시간대별로 Tumor/Blood 비율은 0.94, 0.75, 1.38이었고, Tumor/Muscle의 비율은 0.66, 1.53, 1.11을 나타내었다. 24시간의 감마카메라영상에서 지방육종으로의 국소적인 집적이 확인되었다. 결론: 이상의 결과를 종합해볼 때 지방육종에서 $^{123}I$-BMIPP를 지방육종 영상물질로서의 사용 가능성을 확인할 수 있었다.

• Reproductive and Developmental Biology
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• 제29권3호
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• pp.141-144
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• 2005

This experiment was to investigate whether the mitochondria function assessment can be used for the prediction of sperm fertility through examining the correlation between mitochondria fluoromicroscopic frequency of frozen-thawed eight Hanwoo bull semen using rhodamine123 (R123) and in vitro embryo development following fertilization. Individual sperm were stained in 5 ${\mu}g/mL$ R123-added calcium-free Sp-TALP for 30 min at 0 h, 6 h, 12 h and 24 h after thawing and examined their mid-piece under an epifluorescence microscope using 495 nm excitation filter (x1,000). Three replications were taken, and at least 300 sperm per individual were examined. When semen samples were separated into two groups (good and poor) by sperm motility and fluorescent frequencies at just after thawing, average fluorescent frequencies were remarkably reduced as time going (0 h; $53.29{\~}72.94\%$, 6 h; $21.40{\~}58.90\%$, 12 h; $8.26{\~}25.93\%$, 24 h; $1.00{\~}13.78\%$, irrespective of selected group, and there were no differences at 6 h or 12 h after thawing between selected groups but indicated significant difference at 24 h after thawing (p<0.05). In vitro fertilization rates in good and poor groups ranging $70.8{\~}77.8\%$ and $52.1{\~}84.5\%$, respectively, were not significantly different. However, in vitro development rates of the same groups ranging $25.7{\~}40.0\%$ and $12.9{\~}1.8\%$, respectively, were significant different (p<0.05). These results demonstrate that mitochondria fluoromicroscopic assessment of frozen-thawed bovine sperm may be used as a criterion to select more fertile sperm.