• Journal of Sensor Science and Technology
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• v.7 no.1
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• pp.17-22
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• 1998

A HARP (high-gain avalanche rushing amorphous photoconductor) image pickup tube using $4{\mu}m$ thick a-Se photoconductive film was fabricated and its characteristics were investigated. When the target voltage was increased more than 360 V, the signal current increases rapidly but the dark current of the tube was suppressed less than 3.2 nA up to the voltage of 490 V And the quantum efficiency of the target was about 4.3 at the electric field of $1.1{\times}10^{6}V/cm$ and the wavelength of 440 nm. Also the amplitude response of the HARP tube was 7.5% at 800 TV lines, and the decay lag was 3.4%.

• Plant Biotechnology Reports
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• v.4 no.4
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• pp.269-280
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• 2010

Lilium ${\times}$ formolongi was genetically engineered by Agrobacterium-mediated transformation with the plasmid pCrtZW-N8idi-crtEBIY, which contains seven enzyme genes under the regulation of the CaMV 35S promoter. In the transformants, ketocarotenoids were detected in both calli and leaves, which showed a strong orange color. In transgenic calli, the total amount of carotenoids [133.3 ${\mu}g/g$ fresh weight (FW)] was 26.1-fold higher than in wild-type calli. The chlorophyll content and photosynthetic efficiency in transgenic orange plantlets were significantly lowered; however, after several months of subculture, they had turned into plantlets with green leaves that showed significant increases in chlorophyll and photosynthetic efficiency. The total carotenoid contents in leaves of transgenic orange and green plantlets were quantified at 102.9 and 135.2 ${\mu}g/g$ FW, respectively, corresponding to 5.6- and 7.4-fold increases over the levels in the wild-type. Ketocarotenoids such as echinenone, canthaxanthin, 3'-hydroxyechinenone, 3-hydroxyechinenone, and astaxanthin were detected in both transgenic calli and orange leaves. A significant change in the type and composition of ketocarotenoids was observed during the transition from orange transgenic plantlets to green plantlets. Although 3'-hydroxyechinenone, 3-hydroxyechinenone, astaxanthin, and adonirubin were absent, and echinenone and canthaxanthin were present at lower levels, interestingly, the upregulation of carotenoid biosynthesis led to an increase in the total carotenoid concentration (+31.4%) in leaves of the transgenic green plantlets.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.3
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• pp.232-238
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• 2005

There are growing needs for improving the general performances of the domestic working environment evaluation organizations. For this purpose, introduction of laboratory accreditation program has been suggested. This study was conducted as a part of this effort. With a questionnaire developed in accordance with the ISO/IEC 17025, the current status of industrial hygiene (IH) laboratories in terms of manpower, management and technical aspects. The results of this study were as follows: 1. The average working staffs' number of the working environment evaluation organizations was $6.8{\pm}3.3$ persons. In addition, 49% of all organizations are run by less than 5 persons. This suggests that manpower of Korean IH laboratories is very limited. 2. IH laboratories surveyed in this study obtained 53% of the points by the international standard. And there is significant correlation between the number of staffing and total scores (P<0.05). 3. The period of work experience is one of the most important factors to determine the working capability. The average year of work experience of the laboratories' directors was $13.5{\pm}5.3$ years. Directors with more wok experiences obtained higher scores on the questions that ask to prove the appropriateness of the research methodology (p<0.05). 4. As for academic qualifications of laboratory directors, 14% had Ph.D., 31% with Master's, 29% with Bachelor's, and 4% had Associate degree. There was significant correlation between the total scores and the general managers' academic background (p<0.05). The 27% of laboratory directors have majored in either industrial hygiene or health, 8% majored in medicine, another 8% majored environmental studies, and 6% majored in chemistry. 5. Only 14% of all IH laboratories surveyed employ directors with Certified Industrial Hygienist licence, 41% have general managers with Certified Associate Industrial Hygienist (Level 1) licence, and 45% of all laboratories either employ directors without relevant qualification or did not respond. When the laboratory manger holds relevant qualification, laboratory health and safety management was better (p<0.05). 6. When compared to the general international standard in terms of the management, and 55% in terms of technological level.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.124.1-124.1
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• 2007

• Annual Conference on Human and Language Technology
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• 1996.10a
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• pp.338-345
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• 1996

일본어 특허 문서를 번역하기 위해 개발이 시작된 COBALT-J/K(COllocation - BAsed Language Translator from Japanese to Korea)는 현재 그 번역 대상을 모든 일본어 문서로 확장해 곧, 상용 시스템으로 전환을 바라보고 있다. 이런 시점에서 일반 문서를 대상으로 하는 범용 기계 번역 시스템의 관점에서 시스템을 평가하여 문제점을 찾고, COBALT-J/K가 우선적으로 해결하고자 한 문제들이 올바르게 해결되었는지를 살피고자 한다. 이를 위한 평가 방법으로 문형별로 분류된 다수의 일본어 문장에 대하여 실제 번역을 하여 한국어 번역문과 일본어 원문을 비교하는 방식으로 분석하였으며, 현재 시판되고 있는 J-Seoul에 대해서도 같은 방법으로 실험한 결과를 얻은 후, 이 결과는 평가의 보조 자료로 삼았다.

• Journal of Welding and Joining
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• v.29 no.6
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• pp.56-64
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• 2011

Friction stir spot welding between 5454 aluminum alloy sheets with the different thicknesses of 1.4 and 1.0 mm was performed. In the welding process, the tool for welding was rotated ranging from 500 to 2500, and plunged to the depth of 1.8 mm under a constant tool plunge speed of 100 mm/min. And then, the rotating tool was maintained at the plunge depth during the dwell time ranging from 0 to 7 sec. The pull-out speed of the rotating tool was 100 mm/min. The increase of tool rotation speed resulted in the change of the macrostructure of friction-stir-spot-welded zone, especially the geometry of welding interface. The results of the tensile shear test showed that the total displacement and toughness of the welds were increased with the increase of the tool rotation speed, although the maximum tensile shear load was decreased. However, the change in the dwell time at the plunge depth of the tool did not produce the remarkable variation in the macrostructure and mechanical properties of the welds. In all cases, the average hardness in friction-stir-spot-welded zone was higher than that of the base metal zone. By the friction stir spot welding technique, the welds with the excellent mechanical properties than the mechanically-clinched joints could be obtained.

• Korean Journal of Metals and Materials
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• v.50 no.4
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• pp.263-270
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• 2012

This study investigates the effect of heat treatment on the mechanical properties of a forged Ni-based superalloy called Nimonic 80A. Nimonic 80A ingot samples were fabricated by vacuum spray casting to achieve a fine and homogenized microstructure. The ingot samples were subsequently hot-forged with the diameter of 220 mm at 1373 K. From the center to the surface of the forged Nimonic 80A, its average grain size decreased and its micro-Vickers hardness increased slightly. Solution treatment was carried out at 1353 K with 8 hours of air cooling followed by aging treatment, which was carried out in the range of 873-1073 K with various times from 0.5 to 256 hours. To set the optimum aging conditions, micro-Vickers hardness tests were performed. The maximum hardness value of 388.0 Hv was obtained by aging at 973 K for 32 hours. Also, tensile tests were performed for optimum aging conditions at room temperature and 873 K. The results can be used effectively to perform reasonable heat treatment of Nimonic 80A superalloy.

• Journal of the Korean Institute of Gas
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• v.26 no.6
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• pp.1-8
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• 2022

With the development of the chemical industry, related accidents frequently occur, and fire and explosion accidents account for a large proportion. In order to prevent fire and explosion accidents, places that handle flammable liquids are classified according to the Korean Industrial Standards (KSC IEC60079-10-1) in accordance with the relevant laws. The same applies to laboratories dealing with flammable liquids. This paper verified the applicability of the procedure for classifying explosion hazard areas according to the Korean Industrial Standards when flammable liquid release from the laboratory to form an evaporative pool, and also verified the effect of a change in ventilation speed on the release characteristics. Through this, it was found that it was difficult to apply the criteria for the classification of places at risk of explosion according to the Korean Industrial Standards, and special safety measures should be prepared.

• Journal of Engineering Education Research
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• v.21 no.3
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• pp.38-45
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• 2018

The purpose of this study is to analyze the change of perceptions and images of teachers about engineering, according to practical training in laboratories of engineering research institutes. For this purpose, 149 elementary and secondary school teachers were surveyed before and after visiting the engineering research institutes and examined the perception of engineers and engineering. Through this teacher training program, perceptions and images of most teachers are changed positively and they can understand practically about engineering, and related fields. The results of this study can be used as basic data for the development, operation, and expansion of teacher training using advanced science and technology research institutes with excellent human and material resources.

• Korean Journal of Metals and Materials
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• v.46 no.11
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• pp.713-724
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• 2008

The need to lower the weights of automotive vehicle and to improve the safety of cars has resulted in the development of high strength steels such as TRIP(Transformation Induced Plasticity) and DP (Dual Phase) steel. It is well known that the higher strength of steel shows the poorer press formability. Among the high strength steels, DP steel shows several good characteristics such as low yield ratio, high initial n value, high elongation, high bake hardenability and anti-aging property. However, there's a certain limit in application of DP steels to the automotive panel parts because their poor deep drawbility caused by martensite. In this study, the effect of alloying elements on the deep drawability and recrystallization texture in TS 440MPa grade DP steel with 0.015~0.02% carbon has been investigated on the base of SEM, TEM, XRD and EBSD analysis.