• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.162-162
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• 2012

ZnPc and CuPc molecules stacked similar way in the film, but showed different growth modes in thermal evaporation. The distribution of CuPc crystals did not change by the film thickness, whereas the distribution of ZnPc became random as the increase of the film thickness. The disc type nanograins of CuPc were quite regularly distributed at the initial growth regime and the regular distribution of nanograins was kept during the film growth. On the other hand, ZnPc consisted in ellipsoid shaped nanograins and the distribution of nanograins was not regular in the initial growth regime. The irregular distribution of nanograins changed to the regular mode at the later growth regime by showing structure factor in GISAXS measurement. The different initial nanograin distribution in ZnPc and CuPc was related to the different nanostructure in the mixed layer with C60 to form the bulk heterojunction.

• 전기학회논문지
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• 제66권3호
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• pp.587-592
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• 2017

In the three-phase four-wire low-voltage power distribution equipment, single-phase and three-phase load have been used mainly mixed. Also linear and nonlinear loads have been used together in the same conditions. In a three-phase four-wire distribution line, the current distribution of three-phase linear load is almost constant in each phase during driving or stopping, but the single-phase load is different from each other for each phase in accordance with the operation and stop. So that the voltage unbalance is caused by the current difference of each phase. In the three-phase four-wire distribution system, non-linear load is used with linear load. The presence of single-phase nonlinear loads can produce an increase in harmonic currents in three-phase and neutral line. It can also cause voltage unbalance. In the present study, we analyzed for the voltage unbalance fluctuations by the operation pattern of the single and three-phase linear and non-linear load in three-phase four-wire low voltage distribution system.

• 한국지반공학회논문집
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• 제34권10호
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• pp.39-49
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• 2018

본 연구는 심층혼합시료의 탄성계수를 파악하기 위하여 점토, 모래, 자갈의 입도 구성조건에 안정재 혼합비 8%, 10%, 12%, 14%로 혼합하여 총 320개의 공시체를 제작하였다. 이러한 공시체를 사용하여 일축압축시험을 수행하였고, 일축압축강도와 변형률을 분석하여 할선탄성계수와 접선탄성계수를 구하였다. 실내시험 결과 모든 심층혼합시료는 양생기간과 안정재 혼합비가 증가함에 따라 일축압축강도가 증가하였는데, 이에 대한 할선탄성계수와 접선탄성계수도 증가하는 경향이 뚜렷하게 나타났다. 양생기간에 따른 탄성계수 값의 증가는 할선탄성계수보다 접선탄성계수가 크게 나타났지만, 탄성계수의 증분비는 할선탄성계수가 크게 나타났다. 안정재 혼합비 8%에 대한 탄성계수와 안정재 혼합비 10%, 12%, 14%에 대한 탄성계수 값을 비교하여 안정재 혼합비에 따른 탄성계수를 추정할 수 있는 상관관계식을 공시체 조건별로 구하였다. 심층혼합시료의 입경이 굵어지면 각각의 탄성계수가 증가하는 경향이 나타났으며,가장 큰 영향을 미치는 입경의 분포는 모래질의 구성비가 높을 때 나타났다. 한편 탄성계수증가는 공시체 종류별로는 모래질 공시체가 점토질과 자갈질 공시체보다 크게 나타났다. 이러한 결과를 바탕으로 심층혼합시료의 입도 분포와 안정재 혼합비로 현장의 심층혼합지반의 적절한 지반정수를 제안할 수 있을 것으로 판단된다.

• 한국지형학회지
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• 제20권4호
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• pp.1-13
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• 2013

파도리 해빈은 우리나라의 대표적인 혼합해빈으로써 태안해안국립공원에 속하며 다양한 미지형 경관의 변화가 나타나는 해빈이다. 본 연구의 목적은 소산형 저조간석지와 반사형 비치페이스로 이루어진 5~7m의 대조차 혼합해빈인 파도리 해빈의 퇴적물 분포 특성을 미지형과의 관계를 통해 이동 매커니즘을 밝히고 파랑조건과 조석조건에 따른 미지형 경관변화의 양상을 파악하는 것이다. 연구 결과 첫째, 남부에서 북부로 갈수록 퇴적물 입도가 작아지는 경향성을 보였으며 해빈 남부에 넓게 펼쳐진 파식대가 해식애와 함께 주요한 퇴적물의 기원임을 알 수 있다. 파도리 해빈의 비치페이스와 범의 퇴적물 분포와 해빈을 가로지르는 방향과 연안 방향으로 일정한 입도 분포의 경향성을 보이는 것에 대해서는 선별운반작용으로 설명할 수 있다. 둘째, 혼합해빈의 미지형 경관변화의 주요한 원인에는 파랑과 조석이 있으며, 저파랑 환경에서 범이 발달하고 상부비치페이스에 비치 커습이 나타나는 반면 고파랑 환경에서 범의 규모가 작아지고 상부 비치페이스의 퇴적물은 혼합되는 경향을 보인다.

• Tribology and Lubricants
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• 제23권6호
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• pp.255-260
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• 2007

This paper presents the contact pressure distribution of pin bushing bearings for various lubrication friction modes such as oil film and elastohydrodynamic lubrication contacts, a mixed lubrication contact, a boundary contact, and a dry contact. During a sliding contact of a plain bearing, the boundary and dry rubbing contacts are dominated between a piston pin and a pin bushing bearing. This may come from a micro-scale clearance, an explosive impact pressures from the piston head, and an oscillatory motion of a pin bearing. The computed results show that as the oil film parameter $h/{\sigma}$ is increased from the dry rubbing contact to the oil film lubrication friction, the maximum oil film pressure is radically increased due to an increased viscous friction with a thin oil film thickness and the maximum asperity contact pressure is reduced due to a decreased asperity contact of the rubbing surfaces.

• 대한기계학회논문집B
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• 제21권1호
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• pp.99-112
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• 1997

Mixing process of impinging jets of liquid oxidizer and liquid fuel is simulated by using water and sodium carbonate (Na$_{2}$CO$_{3}$) solution. The shapes of liquid sheets are visualized and flowrate distributions are measured by collecting droplets using measuring cells. Mixing charateristics are studied by using acid-base titration. Stable liquid sheets are formed and two liquid jets are well mixed for symmetric impinging jets. Similarity in flowrate distribution for various measuring heights is observed. For asymmetric impinging jets, liquid sheets become unstable as the difference in the velocities of jets increases. In some extreme cases, liquid sheets are not formed and the jets are separated. Dimensionless variables are adopted demonstrating similarly in flowrate distribution. Mixing characteristics vary significantly with experiment conditions.

• Journal of Yeungnam Medical Science
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• 제28권2호
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• pp.145-152
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• 2011

Background: To evaluate the changes in the radiation dose and temperature distribution on irradiated egg albumin and nanoparticle ($Fe_3O_4$) powder mixed egg albumin. Methods: A new type of phantom was designed by fabricating a $30{\times}30{\times}30cm$ acryl square inside a $3{\times}3{\times}3cm$ small square and dividing it into two parts. In the control group, only egg albumin was irradiated, and in the test group, 25 nm 20 mg/cc, 25 nm 40 mg/cc, and 1 um 40mg/cc nanoparticles with egg albumin were irradiated. The radiation isodose distributions and temperature changes were then observed. Results: No significant changes were observed in the radiation dose and temperature distribution. Conclusion: The nanoparticles were considered not to have had any effect on the radiation dose and temperature distribution under the experimental conditions. Further studies can be conducted based on the changes in the mixture material.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.137-141
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• 2000

This paper presents an application of a new Adaptive Genetic Algorithms(AGA) to solve the Optimal Routing problem(ORP) for distribution system planning. In general, since the ORP is modeled as a mixed integer problem with some various mathematical constraints, it is hard to solve the problem. In this paper, we proposed a new adaptive strategy in GA to overcome the premature convergence and improve the convergence efficiency. And for these purposes, we proposed a fitness function suited for the ORP. In the proposed AGA, we used specially designed adaptive probabilities for genetic operators to consider the characteristics of distribution systems that are operated under radial configuration. The proposed algorithm has been tested in sample networks and the results are presented.

• 한국세라믹학회지
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• 제52권6호
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• pp.403-409
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• 2015

Porous alumina ceramics are involved in many industrial applications due to the exceptional properties of these products. This study addresses the preparation of porous alumina ceramics using hollow microspheres as a pore-forming agent and slip casting as a green-body-forming technique. A uniform distribution of pores is a basic requirement of a porous material. This study investigates three different slurry systems, i.e., as-prepared alumina slurry, alumina slurry electrostatically dispersed by hydrochloric acid (HCl), and slurry dispersed by the commercial dispersant 'Darvan C-N'. At a low viscosity, the hollow microspheres in the slurry tend to float, which causes a non-uniform pore distribution. To avoid this phenomenon, the viscosity of the slurry was increased to the extent that the movement of hollow microspheres ceased in the slurry. As a result, a uniform pore distribution was achieved.

• Management Science and Financial Engineering
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• 제17권2호
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• pp.1-21
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• 2011

This paper considers an integrated inventory-distribution system with a fleet of heterogeneous vehicles employed where a single warehouse distributes a single type of products to many spatially distributed retailers to satisfy their dynamic demands. The problem is to determine order planning at the warehouse, and also vehicle schedules and delivery quantities for the retailers with the objective of minimizing the sum of ordering cost at the warehouse, inventory holding cost at both the warehouse and retailers, and transportation cost. For the problem, we give a Mixed Integer Programming formulation and develop a Lagrangean heuristic procedure for computing lower and upper bounds on the optimal solution value. The Lagrangean dual problem of finding the best Lagrangrean lower bound is solved by subgradient optimization. Computational experiments on randomly generated test problems showed that the suggested algorithm gives relatively good solutions in a reasonable amount of computation time.