• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.729-736
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• 1997

For the recovery of industrial waste heat, a chemical heat transformer based on the reversible reaction between metal chlorides and ammonia gas was designed and a pilot scale unit of 1 kW-1hr was developed. A static calculation, which determined the amount of reacting materials and operating condition of system, and dynamic simulations were performed for the optimal design. The temperature and output power of generator in the system were varying with the amount of salt and heat exchange area. Optimum conditions such as the amount of salt-graphite, apparent density and size of mechanical unit were determined by the dynamic simulation for the system. According to the operating cycle of 4 stages, experimental results of temperature and output power were well agreed with the simulation values. This chemical heat transformer is turned out to be a very promising system for recovery of industrial waste heat because of its effective feature of lifting temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4341-4348
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• 2012

This paper presents a web-based real-time monitoring system for a photobioreactor using an WiFi wireless network. An WiFi interface can support high speed data transfer, up to 11Mbps and it can be compatible with commercial wireless LAN environment. Thus, the proposed cell culture based on WiFi network can be easily applied to the reconfigurable system and real-time monitoring system. In this paper, we integrate the commercial WiFi module to the various bio-sensors and sensor control board to configure the wireless network. After we evaluate application S/W for monitoring the environment within incubator, we verify the proposed sensor networks for a cell culture system and its monitoring system. This result can be applicable for various bio-applications that require the network configuration and real-time monitoring system.

• Journal of Energy Engineering
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• v.12 no.4
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• pp.289-301
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• 2003

To develop a chemical-looping combustion technology, conceptual design of 50 kW thermal chemical-looping combustor, which is composed of two interconnected pressurized circulating fluidized beds, was performed by means of mass and energy balance calculations. A riser type fast fluidized bed was selected as an oxidizer and a bubbling fluidized bed was selected as a reducer by mass balance for the chemical-looping combustor. Calculated values of bed mass, solid circulation flux, and reactor dimension by mass and energy balance calculations were suitable for construction and operation of chemical-looping combustor. It is concluded from the comparison of the design results and operating values of commercial circulating fluidized bed that the process outline is realistic. Moreover, the previous results support that oxygen carrier particle, NiO/bentonite, fulfills the conversion rates needed for the proposed design. The effects of system capacity, metal oxide content in a oxygen carrier particle, amount of steam input, gas velocity, and solid depth on design values were investigated and the changes in the system performance can be estimated by proposed design tool.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.1
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• pp.1-9
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• 2013

In this study of Eccentric Braced Frames have identified the following target eccentricity on the length of the inelastic behavior of the reaction by calculating the correction factor by comparing it to the value suggested by the earthquake provided material for the rational design aims to There are. As a variable-length V-braced frame analysis model stations were set up. Eccentricity faults in the model according to the length stiffness ratio, the maximum amount of energy dissipation were analyzed base shear and multi-layered model of the reaction from the eccentricity correction factor calculated on the length of the building standards proposed by KBC 2009 in response eccentricity correction factor calculated from The length varies. does not have the same response modification factor was confirmed.

• Clean Technology
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• v.21 no.4
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• pp.229-234
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• 2015

Recently, there are increasing numbers of study regarding hydrogen fuels but researches on desulfurization of diesel are rare. In this study, we performed diesel desulfurization reactor design by computation fluid dynamics simulation. By analyzing the change in flow and sulfur concentration at the outlet according to the changes in flow rate, reactor length, and reactor diameter, we have found the minimum catalyst performance for the given flow rate condition and the relation between the reactor performance and the reactor size and shape. We also studied the effects of permeability of the packed bed on the flow and sulfur concentration distribution. The present work can be utilized to design a diesel desulfurization reactor for a fuel cell used in ships. Furthermore, the present work also can be used to design low sulfur diesel supply in oil refineries and therefore contribute to the development of clean petrochemical technology.

• Korean Journal of Food Science and Technology
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• v.54 no.1
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• pp.1-7
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• 2022

Riboflavin (Rb), in the presence of methionine (Met) under light, generates superoxide radicals that can reduce nitro blue tetrazolium (NBT) to its corresponding formazan. The Rb-Met/NBT system has been used to measure the superoxide dismutase (SOD)-like activities of various antioxidants. However, the reaction mechanisms have not been clearly defined, and the assay conditions are not consistent. In this study, the effects of different photosensitizers and amino acids on NBT reduction in different solvents were investigated. NBT reduction in the Rb-Met/NBT system was more pronounced in phosphate-buffered saline, compared to distilled water or Tris (pH 7.5); histidine (His) instead of Met also led to considerable Rb-induced NBT reduction. Among the photosensitizers, methylene blue with His caused potent NBT reduction in Tris. Rb-induced NBT reduction combined with Met or His was quantitatively inhibited by SOD or gallic acid, but did not affect MB-induced reduction sensitively.

• Proceedings of the Korean Information Science Society Conference
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• 2007.10d
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• pp.589-592
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• 2007

CoSlide 협업 시스템은 웹데브 기반의 CoSlide 서버와 윈도우즈 응용프로그램인 CoSpace 클라이언트로 구성된다. CoSlide 서버는 Jakarta Slide 서버의 확장으로 협업시스템 구성원간의 자원 공유를 위한 다양한 종류의 작업장을 지원하며, CoSpace 클라이언트는 CoSlide 서버의 다양한 기술 지원을 사용자 중심의 인터페이스로 제공한다. 협업을 동적으로 지원하기 위해서는 워크플로우 시스템이 필요하다. 워크플로우 시스템은 협업시스템에 등록된 사용자가 워크플로우가 정의된 작업장에 자원을 등록하였을 때 정의된 워크플로우에 따라서 자원의 이동, 복사 그리고 메시지전송 등의 과정을 자동적으로 수행한다. 워크플로우 정의는 XML 파일 형식으로 워크플로우 작업장에 생성되어 존재하며 반응적 워크플로우가 발생하였을 때 XML 파일의 정의에 따라 자동적으로 이뤄진다. 협업 시스템에 워크플로우 시스템을 적용시키면 협업 시스템에 등록된 자원을 수동으로 분류하거나 협업에 필요한 다른 그룹의 특정 사용자에게 수동으로 전송해야 하는 불편함을 없앨 수 있다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.179-179
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• 2012

국내에는 나노 분말 제조를 위한 RF 열플라즈마 시스템 제조 기술이 확보되어 있지 않고, 또한 나노 파우더 제조를 위한 공정 기술 역시 외국 업체에 전적으로 의존하고 있다. 본 연구에서는 나노 분말 제조를 위한 RF 열 플라즈마 토치 시스템 개발과 고품질의 나노 파우더 합성 공정 기술을 확립하여 필요 기관에 제공하는데 있다. 80 kW RF Plasma torch system의 설계 및 제작을 위해 플라즈마 Simulator인 CFD-ACE+를 이용하여 플라즈마 토치 및 반응로 내의 온도 분포, 유체 유동, 열전달 등의 해석을 통해 플라즈마 토치 및 반응로의 반경 및 길이, 구조의 설계 값을 도출하여 반응로를 설계하여 RF 파워, RF 플라즈마 토치(Torch), 반응기(Reactor), 사이클론(Cyclone), 포집부(Collector), 열교환기 및 진공배기 시스템으로 구성하였다. Si 나노 소재의 경우, 이차전지 음극재에 적용이 가능한 대표적인 소재로서 높음 비용량과 충/방전시 부피팽창을 감소시킬 수 있어 이차전지의 고용량 구현을 위해서는 가장 중요한 소재중 하나로 많은 관심 재료로 평가 받고 있다. 따라서 본 연구에서는 상용화된 Si 원료 powder를 사용하여 고상 분체 공급 장치를 통하여 고온의 플라즈마를 통과시켜 기상화 및 결정화과정을 통해 Si 나노분말을 제조하였다. 공정 변수로서 공정압력 및 플라즈마 power, Gas의 변화량에 따른 나노 분말의 제조 특성에 대한 실험을 진행한 후 제조된 나노 분말을 비표면적측정(BET) 및 SEM 측정 결과 분석을 통하여 시스템 특성을 파악하였으며 제조된 Si 나노 파우더는 이차전지 음극재로서 770 mAh/g의 용량과 93%@50 cycle 수준의 유지율을 나타내었다.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1055-1060
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• 2009

In this paper, we design an e-Learning system for the Driver's License Teste studying through the Internet. The proposed system make users to be arrived at the goal for the license in a shorter time by offering learning contents and items according to the item-responses made by the users based on the Item Response Theory. Moreover we design the scheme to give the optimum items and the most necessary content to the user during the learning procedure in the form of concept-based objects. All the items in the problem bank DB maintain their difficulties, discriminations, and guessing parameters as is the case of 3-parameter logistic model. In addition user profile DB stores users' status informations, item responses, and ability parameters. Using these structures and combining agents, we can offer the optimum learning process or dynamic personalized studying structure to the user. We can construct interface agent and content selection and feedback agent with the DB's described above. User can study without any awareness of system operations or personal fitting scheme.

• Journal of The Korean Association of Information Education
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• v.5 no.2
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• pp.268-278
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• 2001

This study is design and implementation of diagnosis module using item response theory to assess level of student's knowledge in web-based instruction systems. Item response theory uses responses to items on a test or survey questionnaire to simultaneously locate both the items on the latent trait defined by the set of items while simultaneously scaling each item on the very same dimension. Existing method of measurement in web-based instruction system provided dichromatic learning after to be assess just with the total scores of exam. This measurement has an error that do not consider the level of student's knowledge. Moreover, this method can't perform an exact diagnosis of student knowledge and make student modeling to construct intelligent tutoring system. In this study, we present that design and implement a diagnosis module using item response theory to assess level of student's knowledge in web-based instruction systems