• Journal of Advanced Marine Engineering and Technology
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• v.24 no.3
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• pp.113-120
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• 2000

On the absorber of absorption chiller/heater, LiBr solution at high concentration is sprinkled on a bundle of horizontal tube cooled by cooling water. In this case, the conditions of LiBr solution and cooling water have an influence on heat/mass transfer coefficient in this system. Therefor it is important to find optimal operation conditions of absorption chiller/heater to save energy. Heat and mass transfer coefficient increased with the increase of solution flow rate, and also heat and mass transfer rate increased but overall heat and mass transfer coefficient decreased by increasing the solution concentration within the experimental range. The superheating of the solution resulted in superior heat transfer character to a state of equilibrium from the point of heat flux and overall heat transfer coefficient.

• Proceedings of the KSME Conference
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• 2000.04b
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• pp.328-334
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• 2000

This research was concerned with the enhancement of heat transfer by surfactant added to the aqueous solution of LiBr. Different horizontal tubes were tested with and without an additive of normal octyl alcohol. The test tubes were a bare tube, floral tube, hydrophilic tube. The additive concentration was about $0.05{\sim}5.5mass%$. The heat transfer coefficient was measured as a function of solution flow rate in the range of $0.01{\sim}0.034 kg/ms$. The experimental result were compared with cases without surfactant. The enhancement of heat transfer by Marangoni convection effect which was generated by addition of the surfactant is observed in each test tube.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.5
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• pp.581-588
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• 1998

An experimental study of the absorption process of water vapor into Lithium Bromide solution was performed. For the purpose of development of high performance absorption chiller-heater utilizing Lithium Bromide solution as working fluid, the absorber is the most effective to improve the performance of an absorber because it requires the largest heat transfer area in an absorption chiller-heater system. This paper introduces bare tube and floral tube for the absorber of absorption chiller-heaters. floral tube has higher heat and mass transfer performance than bare tube conventionally used in absorbers and the it is expected to perform high heat and mass transfer. This paper will provide important information on the selection of absorber tubes in commercial absorption chiller -heaters.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.4
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• pp.478-485
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• 2000

An experimental study of the absorption process of water vapor into lithium bromide solution was performed. For the purpose of development of high performance absorption chiller-heater utilizing Lithium Bromide solution as working fluid, the absorber is the most effective to improve the performance of an absorber because it requires the largest heat transfer area in an absorption chiller-heater system. This paper introduces bare tube and inner ribbed notched fin tube for the absorber of absorption chiller-heaters. Inner ribbed notched fin tube has about 10∼20% higher heat and mass transfer performance than bare tube conventionally used in absorbers and the it is expected to perform high heat and mass transfer. This paper will provide important information on the selection of absorber tubes in commercial absorption chill-heaters.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2003.05a
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• pp.277-286
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• 2003

첨단기술 분야의 발전 및 기술개발 촉진을 위해서는 개발된 기술의 기업간 이전거래활동이 활발히 이루어져 기술의 상업화와 고도화가 촉진되어야 한다. 이를 위해서는 기술중개기관이나 거래소와 같은 제도적 기반을 갖추는 것뿐만 아니라 특정 기술이 가지는 가치를 중립적 관점에서 평가할 수 있는 방법론의 개발이 요구된다. 기술 구매자와 기술 판매자 사이의 가격협상을 위해서는 특정 기술이 보유한 중립적이고 객관적인 가치가 우선적으로 제시되어야 하기 때문이다. 본 논문은 기술이전거래 촉진을 위한 기술가치평가 모형의 개발과 평가모형에 따른 평가과정을 지원하는 기술가치평가시스템의 개발을 목적으로 차고 있다. 기술가치평가시스템은 웹 기반으로 개발되어, 관심 있는 사용자는 웹 브라우저를 통해 기술적 가치를 실시간으로 신속하고 효율적으로 평가할 수 있도록 구현되어 있다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.3
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• pp.24-35
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• 2014

This paper examines, from the perspective of the structure-conduct-performance (S-C-P) paradigm, the structural factors that determine R&D concentration in industries. The results are as follows. First, an industry's R&D concentration is directly related to its market concentration, R&D intensity, capital intensity, and technological opportunities. In contrast, the higher an industry's performance, the more likely the diffusion of R&D investment is for firms belonging to that industry. Second, an industry's R&D concentration has a positive effect on its market concentration but a negative effect on its performance, suggesting that governments should adopt R&D policies that would induce more firms to invest in R&D instead of focusing only on a few firms to enhance industry performance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.8
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• pp.1097-1103
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• 2000

This research was concerned with the enhancement of heat transfer by surfactant added to the aqueous solution of LiBr. Different horizontal tubes were tested with and without an additive of normal octyl alcohol. The test tubes were a bare tube, floral tube and hydrophilic tube. The additive mass concentration was about 0.05${\sim}$5.5%. The heat transfer coefficient was measured as a function of solution flow rate for the range of 0.01${\sim}$0.034 kg/ms. The experimental results were compared with cases without surfactant. The enhancement of heat transfer by Marangoni convection effect generated by the addition of the surfactant is observed in each test tube. The increase of heat transfer coefficient by surfactant addition is about 35${\sim}$90% for bare tube, 40${\sim}$70% for the floral tube, 30${\sim}$50% for the hydrophilic tube and was higher for the cases with smaller a little solution flow rates.

• Journal of Power System Engineering
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• v.14 no.1
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• pp.22-26
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• 2010

Generally, it is a method to remove the fouling cleaning the plate heat exchanger with chemicals or polishing with a brush or cloth after stopping the equipment and disassembling heat exchanger. However, the equipment must be stopped and taken apart when using this method, which causes an unnecessary work to assemble again after cleaning it. In this study, it has developed and tested the equipment which can automatically clean the fouling on plate heat exchanger at regular intervals with air bubbles. It indicated that the overall heat transfer coefficient had decreased without significant differences similar to that calculated without air bubbles until after 72 hours when making air bubbles to remove fouling ingredient on the surface of heat transfer area every 10 minutes per 2 hours. However, it showed that there was a 10% higher of heat transfer effect compared to the case without air bubbles of after 192 hours.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.183-184
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• 2005

In this paper. a new small size Lateral Trench Electrode Power IGBT is proposed. The entire electrode of proposed LIGBT is placed in trench oxide. The forward blocking voltage of the proposed LIGBT is improved by 1.6 times with that of the conventional LIGBT. The forward blocking voltage of proposed LIGBT is 500V. At the same size. a increase of the forward blocking voltage of about 1.6 times relative to the conventional LIGBT is observed by using TMA-MEDICI which is used for analyzing device characteristics. Because the electrodes of the proposed device are formed in trench oxide. the electric field in the device are crowded to trench oxide. We observed that the characteristics of i the proposed device was improved by using TMA-MEDICI and that the fabrication of the proposed device is possible by using TMA-TSUPREM4.

• Journal of Convergence for Information Technology
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• v.8 no.5
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• pp.205-210
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• 2018

We will investigate in depth the reasons why companies have a negative mindset and produce complaints about the internship system itself. On the other hand, we try to find out the success factors of domestic companies that have introduced and operate the exemplary internship system, and prepare policies to disseminate them. In order to do this, I would like to diagnose the problems related to the internship system in the current industry through questionnaires or interviews with existing internship students. It is hoped that this will help the participating students to have a positive mindset about the company and further contribute to the career search and adaptation to the firm from the university to the firm.