• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1752-1757
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• 2008

Simple and highly efficient droplet merging method is proposed, which enables two nanoliter or picoliter droplets to merge regularly in a straight microchannel. We observe that two droplets of the same size but of different viscosities are merged by velocity difference induced as they are transported with the carrier fluid. To make viscosity difference, the mass ratio of water and glycerol is varied. Two droplets of the same size or of different sizes are generated alternatingly in the cross channel by controlling flowrates. This droplet merging method can be used to mix or encapsulate one target sample with another material, so that it can be applied to cell lysis, particle synthesis, drug discovery, hydrogel-bead production, and so on.

• 한국구조물진단유지관리공학회 논문집
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• 제5권1호
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• pp.131-140
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• 2001

In general, the deterioration induced by the freezing and thawing cyclic in concrete structures often leads to the reduction in concrete durability by the cracking or surface spalling. If it can prediction of concrete deterioration subjected to cyclic freezing and thawing, we can rationally do the design of mix proportion in view of concrete durability and the maintenance management of concrete structures. Therefore in this study a prediction method of deterioration for concrete structures subjected to the irregular freezing and thawing is proposed from the results of accelerated laboratory freezing and thawing test using the constant temperature condition and the in-situ weathering data. Furthermore, to accurately predict the concrete deterioration, a method of modification for the effect of hydration increasing during rapid freezing and thawing test is investigated.

• Bulletin of the Korean Chemical Society
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• 제30권5호
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• pp.1077-1079
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• 2009

To minimize the variance in the quantification of solid-state phases in powder samples, gently placing polycrystalline samples one next to another directly in a sample holder is better than trying to mix them homogeneously prior to transferring to a sample holder. However, the solid-state cross polarization-magic angle spinning (CP-MAS) nuclear magnetic resonance (NMR) spectroscopy results demonstrated that it is essential in this sampling method to place all the samples in the location of consistent signal sensitivity. The same sampling method may be employed in other spectroscopic quantification techniques of solid-state phases if the method to limit the sample to the location with uniform signal sensitivity in the sample holder is adapted to each technique.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 가을 학술발표회 논문집
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• pp.24-30
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• 1996

Nowadays, Government is modifying envioronment regulatons, but PC factories, having been constructed in 1990, are running out heavy cost in disposal of waste concrete, and hardly studying how accelerator curing method affects in compressive strength. In this study, possibility that waste concrete, produced in PC factory, can be used in PC products, is reviewed, and them captures strength characteristics by curing method. The results can be summed as follows. In order to recycle concrete the mix ratio of recycled aggregate to 50 percent of less than must decrease also in summer of four seasons strength gap by curing method is very small.

• 한국산학기술학회논문지
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• 제3권2호
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• pp.89-93
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• 2002

PbO 함유 다성분계유리 및 파이버를 제조하였으며, PbO함유 유리는 이중도가니법(double crucible methodo에 의한 높은 개구수를 갖는(high-numerical aperture : N.A.) 광파이버(optical fiber) 제조에 적합하였다. 본 실험에 있어서는 SiO₂, PbO를 주성분으로 하고 K₂O, Na₂O, B₂O₃, A1₂O₃등의 산화물을 적량 배합하였으며, 또한 double crucible method에 의해 제조된 파이버의 광학적, 기계적 및 구조적 특성을 관찰하였다.

• 한국구조물진단유지관리공학회 논문집
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• 제7권1호
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• pp.279-288
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• 2003

This study is the development of method on repairing concrete structure for progressing the durability of reinforced concrete. This method is wet spray method which compress and conduct mortar pre-mixed with polymer powder to hose by high pressure pump and spray it on the section of concrete structure through nozzle made specially. Characters of this method are that materials are selected with the sort of structure and the cause of deterioration and macro pores are removed in repaired section by conducting with high pressure and spraying with high velocity for progressing the durability of concrete structure. This study has carried out that the minimum capacity of rebound was measured with various condition and physical properties of sample made by spray method were estimated in comparing with sample made by previous hand method. Also, properties of long-term have carried out after this method was applied on site. According to experimental study, the capacity of rebound showed below 5% and physical properties of sample made by spray method were superior to that of sample made by hand method and physical and durable properties of long-term showed excellence.

• 한국산학기술학회논문지
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• 제15권6호
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• pp.3813-3820
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• 2014

최근 전기 사용량이 증가하면서 전력수요와 공급능력의 불균형으로 인하여 전력예비율은 점차 감소되고 있으며, 전력 공급의 신뢰성도 떨어지고 있다. 이러한 배경 하에 전기저장장치(Battery Energy Storage System)는 수요관리의 유력한 수단 가운데 하나로써 중요성이 점차 부각되고 있다. 하지만, 이차전지를 이용한 전기저장장치는 아직 고가이므로 전력계통에 도입하여 운용하기 위해서는 경제성 평가가 필수적이다. 따라서, 본 논문에서는 전력회사용 BESS의 경제성평가를 위하여 BESS를 고려한 전원베스트믹스와 축사근사법을 이용하여, BESS의 도입 전 연간 운용비용과 BESS의 도입 후 연간 운용비용을 비교하여 최적의 BESS 도입용량과 도입비용을 산정하는 알고리즘을 제안하였다. 또한, 수용가용 BESS의 경제성평가에서는 피크세이빙 및 부하평준화 기능을 통하여 수용가의 기본전기요금과 사용량전기요금을 감소시켜 최대한의 메리트를 추구하는 경제성평가 알고리즘을 제시하였다. 제안한 알고리즘을 이용하여, 모델 전력계통과 수용가(교육기관)를 대상으로 BESS의 경제성을 분석하여, 본 논문에서 제시한 알고리즘의 유용성을 확인하였다.

• 한국식품영양학회지
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• 제33권1호
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• pp.111-115
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• 2020

The purpose of this study is an application of Lee's Menu Engineering (LME) method for menu analysis on the eight kinds of pizza selected from 17 kinds of pizza served by an Italian restaurant near by the Keimyung College University campus. The eliminated nine items were in the third quadrant or below the trend line. The LME method is more efficient than generally used methods such as the Miller, Kasavana & Smith, Uman, Pavesic and Merricks & Jones method. The LME method comprises reference lines and four quadrants created by x, y axes and its average values. The x and y axes comprise the sales ratio (MM%, percentage of the Menu Mix) and the weighted contribution margin (WCM%, percentage of the Weighted Contribution Margin) respectively. The obtained results are such that total sales increased by 1.59% from 58,747,200 won to 59,684,000 won, despite the decrease in sales volume. Total contribution margin also increased from 35,248,320 won to 35,810,400 won. The trend line also shows from y=0.9147x (R²=0.703) to y=0.9944x (R²=0.9893). These results indicate that the LME method is superior in practical applications.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.695-702
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• 2002

Shotcrete (or Sprayed concrete) has been used as an important support material in New Austrian Tunnelling Method (NATM). Since the mid of 1990, permanent shotcrete tunnel linings such as Single-shell, NMT (Norwegian Method of Tunnelling) has been constructed in many countries for reducing the construction time and lowing construction costs instead of conventional in-situ concrete linings. Among essential technologies for successful application of permanent shotcrcte linings, high performance shotcrete providing high strength, high durability, better pumpability has to be developed in advance as an integral component. This paper presents the Ideas and first experimental attempts to increase early strength and bond strength of wet-mixed Steel Fiber Reinforced Shotcrete(SFRS) in sump water condition. In order to increase early strength, a new approach using high-early strength cement with liquid alkali-free accelerator has been investigated From the results, wet-mix SFRS with high-early strength cement and alkali-free accelerator exhibited excellent early strength improvement compared to the ordinary portland content and good bond strength even under sump water condition.

• Journal of the Korean Statistical Society
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• 제21권2호
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• pp.187-200
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• 1992

Samples are often found to be too heterogeneous to be explained by a one-parameter family of models in the sense that the implicit mean-variance relationship in such a family is violated by the data. This phenomenon is often called over-dispersion. The most frequently used method in dealing with over-dispersion is to mix a one-parameter family creating a two parameter marginal mixture family for the data. In this paper, we investigate performance of estimators such as maximum likelihood estimator, method of moment estimator, and maximum quasi-likelihood estimator in negative binomial and beta-binomial distribution. Simulations are done for various mean parameter and dispersion parameter in both distributions, and we conclude that the moment estimators are very superior in the sense of bias and asymptotic relative efficiency.