• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.04a
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• pp.24-24
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• 1999

This study addresses the effectiveness of TEC(Thermoelectric cooler) application for spacecraft thermal control. The required radiator area and power consumption characteristics of active thermal control using TEC are compared with the passive control at BOL and EOL through unsteady thermal analyses by calculating external heat fluxes. When the component operating temperature is low enough in TEC active control, the required radiator area can be smaller than the passive thermal control. TEC also needs less power consumption than the passive control under the condition that the temperature of cooling pars is low enough and/or the design temperature margin of the components is narrow enough.

• Advances in Energy Research
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• v.8 no.4
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• pp.253-264
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• 2022

This paper deals with the effects of design (active area, current density, membrane conductivity) and operating parameters (temperature, relative humidity) on the performance of hydrogen-fuelled proton exchange membrane (PEM) fuel cell. The design parameter of a PEM fuel cell with the active area of the single cell considered in this study is 25 cm² (5 × 5). The operating voltage and current density of the fuel cell were 0.7 V and 0.5 A/cm² respectively. The variations of activation voltage, ohmic voltage, and concentration voltage with respect to current density are analyzed in detail. The membrane conductivity with variable relative humidity is also analyzed. The results show that the maximum activation overpotential of the fuel cell was 0.4358 V at 0.21 A/cm² due to slow reaction kinetics. The calculated ohmic and concentrated overpotential in the fuel cell was 0.01395 V at 0.76 A/cm² and 0.027 V at 1.46 A/cm² respectively.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.337-342
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• 2004

Since 1992, Philips has been developing polymer OLEDs resulting in a first commercial monochrome display just 10 years later. Philips is now focusing on the technology development required to mass-produce full-color polymer OLDE displays, based on passive and active-matrix addressing. High precision inkjet printing has been chosen as the deposition technology for the OLED material. In this paper, we give an overview of the activities of Philips in the area of mobile OLED applications and explore the route towards large screen OLED television.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11a
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• pp.230-235
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• 1996

The new concept of dry area formation based on Poisson distribution of active nucleation sites and the concept of the critical active site density is presented. A simple statistical model is developed to predict the change of slope of the boiling curve up to critical heat flux (CHF) quantitatively. The predictions by the present model are in good agreement with the experimental data. Also it turns out that the present model well explains the mechanism on how the surface wettability influences CHF.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.250-252
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• 2002

Since DAS(Distribution Automation System) has been typically managed for feeder automation in passive manner, it has to be managed by operator when feeder over loadings are detected therefore it may be possible for propagating the over loaded area by operator's mistake. To overcome the defect, The author proposed the feeder switch automation using active database.

• Journal of the Korean Chemical Society
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• v.66 no.2
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• pp.78-85
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• 2022

Natural white clay was treated with 6 M of H₂SO₄ and heated at 80℃ for 6 h under mechanical stirring and the resulting acid active clay was used as an adsorbent for the removal of Cs⁺ in water. The physicochemical changes of natural white clay and acid active clay were observed by X-ray Fluorescence Spectrometry (XRF), BET Surface Area Analyser and Energy Dispersive X-line Spectrometer (EDX). While activating natural white clay with acid, the part of Al₂O₃, CaO, MgO, SO₃ and Fe₂O₃ was dissolved firstly from the crystal lattice, which bring about the increase in the specific surface area and the pore volume as well as active sites. The specific surface area and the pore volume of acid active clay were roughly twice as high compared with natural white clay. The adsorption of Cs⁺ on acid active clay was increased rapidly within 1 min and reached equilibrium at 60 min. At 25 mg L^- of Cs⁺ concentration, 96.88% of adsorption capacity was accomplished by acid active clay. The adsorption data of Cs⁺ were fitted to the adsorption isotherm and kinetic models. It was found that Langmuir isotherm was described well to the adsorption behavior of Cs⁺ on acid active clay rather than Freundlich isotherm. For adsorption Cs⁺ on acid active clay, the Langmuir isotherm coefficients, Q, was found to be 10.52 mg g^-1. In acid active clay/water system, the pseudo-second-order kinetic model was more suitable for adsorption of Cs⁺ than the pseudo-first-order kinetic model owing to the higher correlation coefficient R² and the more proximity value of the experimental value q_e,exp and the calculated value q_e,cal. The overall results of study showed that acid active clay could be used as an efficient adsorbent for the removal of Cs⁺ from water.

• Journal of the Economic Geographical Society of Korea
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• v.7 no.1
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• pp.29-43
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• 2004

In this paper, we tries to investigate whether there are some differences of the characteristics between venture business in the metropolitan area and in the local area. We set up some hypotheses on the regional characteristics of venture business and test those using the raw data of Small and Medium Business Administration (SMBA) survey on the management of venture business. Our main findings are as follows: First, we analyze the industrial composition of ventures by region and find that in the metropolitan area high-technology venture business which is belong to software, or information, or communication industries is given much weight. But in the provinces, ventures belong to traditional manufacturing industries is given much weight. Second, we compared the characteristics of business network by region and find that the ventures in the metropolitan area are active in technical cooperation among companies and want strategic tie-ups in marketing field, whereas the ventures in the provinces are active in technical cooperation with university and want strategic tie-ups in technical development field. Third, ventures in the metropolitan area are more excellent in technical development and management than ventures in the provinces.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.552-556
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• 2016

Obstacle detection is a key feature in the safe driving control of electric wheelchairs. The suggested obstacle detection algorithm was designed to provide obstacle avoidance direction and detect the existence of cliffs. By means of this information, the wheelchair can determine where to steer and whether to stop or go. A 3D depth camera (Microsoft KINECT) is used to scan the 3D point data of the scene, extract information on obstacles, and produce a steering direction for obstacle avoidance. To be specific, ground detection is applied to extract the obstacle candidates from the scanned data and the candidates are projected onto a 2D map. The 2D map provides discretized information of the extracted obstacles to decide on the avoidance direction (left or right) of the wheelchair. As an additional function, cliff detection is developed. By defining the "cliffband," the ratio of the predefined band area and the detected area within the band area, the cliff detection algorithm can decide if a cliff is in front of the wheelchair. Vehicle tests were carried out by applying the algorithm to the electric wheelchair. Additionally, detailed functions of obstacle detection, such as providing avoidance direction and detecting the existence of cliffs, were demonstrated.

• Current Photovoltaic Research
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• v.5 no.3
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• pp.95-99
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• 2017

The interconnecting shingled solar cells method shows extremely high ratio active area per total area and has the excellent potential for high power PV (photovoltaic). Compared to the conventional module, it can have much more active area due to busbar-free structure. The properties of ECA (electrically conductive adhesives) are significant to fabricate the shingled array PV since it should be used in terms of electric and structural connection. Various ECA were tried and characterized to optimize the soldiering conditions. The open circuit voltage of shingled array cells showed a three-fold increase and efficiency was also increased by 1.63%. The shingled array cells used in CE3103WLV showed the highest power and in CA3556HF the lowest curing temperature and very fast curing time.

• The Korean Journal of Ecology
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• v.23 no.4
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• pp.339-345
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• 2000

Heilongjiang Province has set up 104 nature reserves, with a total area of 2,641,700 ha, or 5.88% of the total area of the province. These constitute a network of nature reserves comprising most important types of nature reserves. and play an active role for improving the protection of the ecological environment and for the continuous economic and social development of the province. But in the management of these nature reserves, there are still some problems with people's idea, with educating the public, and with capital investment. These problems should be treated seriously. To preserve our natural heritage and biodiversity and to promote the sustainable development of our society and economy, it is projected that by the year 2000. the number of nature reserves in Heilongjiang is to reach 109, covering 6.17% of the total land area of the province. This percentage will be further increased to 8.62% by 2010, at which time the network of nature reserves is to have a proper distribution and comprehend all the important types of nature reserves. This will ensure the healthy development of the cause of nature conservation. with systematic planning, active protection. and sustainable use, so that ecological and social benefits can be developed hand in hand with economic benefits.