• 한국미생물·생명공학회지
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• 제14권5호
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• pp.427-432
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• 1986

The regulation of three ammonia assimilatory enzymes, GDH (glutamate dehydrogenase), GS (glutamine synthetase) and GOGAT (glutamate synthase), has been examined in C. glutamicum. Three kinds of arginine auxotrophs blocked in each step of arginine biosynthetic pathway from glutamate were selected as arg 5, arg 6, arg 8. Histidine and tryptophan auxotrophs were also selected because histidine and tryptophan repressed GS biosynthesis in E. coli. These strains were cultured on the media containing nitrogen-excess and limited conditions, to compare the specific activities of ${\alpha}$-ketoglutarate dehydrogenase(${\alpha}-KGDH$), GDH, GS, GOGAT from the cell-free extracts. These results showed that enzyme levels of ${\alpha}-KGDH$ and GDH from 3 kinds of arginine auxotrophs, histidine and tryptophan auxotrophs in nitrogen-excess condition and those of GS and GOGAT in nitrogen limited condition were increased compared with opposite condition. The tryptophan and histidine auxotrophs showed higher level of glutamate and glutamine than parental strains and other mutants. it is assumed that the higher levels of ${\alpha-KGDH}$ and GDH from mutants in nitrogen-excess condition promoted the accumulation of glutamate and glutamine in fermentation broth. The inhibition of GS activities by ADP suggested that GS is regulated by energy charge in C. glutamicum. The results with histidine, tryptophan, glycine, alanine, serine and GMP implied that a system of feedback inhibition were effective. The GDH, GS and GOGAT biosynthesis in culture broth was markedly repressed by the nature and kinds of available nitrogen sources such as tryptophan, proline, glycine, alanine, serine and tyrosine.

• 한국재료학회지
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• 제23권12호
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• pp.680-686
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• 2013

Tungsten oxide films were prepared by an electrochemical deposition method for use as the anode in rechargeable lithium batteries. Continuous potentiostatic deposition of the film led to numerous cracks of the deposits while pulsed deposition significantly suppressed crack generation and film delamination. In particular, a crack-free dense tungsten oxide film with a thickness of ca. 210 nm was successfully created by pulsed deposition. The thickness of tungsten oxide was linearly proportional to deposition time. Compositional and structural analyses revealed that the as-prepared deposit was amorphous tungsten oxide and the heat treatment transformed it into crystalline triclinic tungsten oxide. Both the as-prepared and heat-treated samples reacted reversibly with lithium as the anode for rechargeable lithium batteries. Typical peaks for the conversion processes of tungsten oxides were observed in cyclic voltammograms, and the reversibility of the heat-treated sample exceeded that of the as-prepared one. Consistently, the cycling stability of the heat-treated sample proved to be much better than that of the as-prepared one in a galvanostatic charge/discharge experiment. These results demonstrate the feasibility of using electrolytic tungsten oxide films as the anode in rechargeable lithium batteries. However, further works are still needed to make a dense film with higher thickness and improved cycling stability for its practical use.

• 건설안전기술
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• 통권38호
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• pp.79-87
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• 2006

Formwork is a temporary structure that supports its weight and that of freshly placed concrete as well as construction live loads. In constructions site, pipe supports are usually used as shores which are consisted of the stab formwork. The strength of a pipe support is decreasing as it is frequently being used at the construction site. Among the accidents and failures that occur during concrete construction, there are many formwork failures which usually happen at the time concrete is being placed. The objective of this study is to find out the strength change of used pipe support and unused pipe supports according to aging. In this study, 2857 pipe supports were prepared. Among these pipe supports, 2337 pipe supports were lent to the construction companies free of charge. 520 pipe supports were kept on the outside. Compressive strength was measured by knife edge test and plate test at each 3 month. Test results show that the strength of unused pipe supports as well as used pipe supports was decreasing according to age, use frequency and load carrier, and the strength of used pipe supports was lower than the strength of unused pipe supports at the same age. So, the strength of used pipe supports from 191 days to present day was not satisfied the specification of KSF 8001. In this study, the strength of pipe support according to age, use frequency and load carrier was predicted using SPSS 12.0. It was known that the strength of pipe support using for 5 years was reduced to 42.8%. According to these results, it shows that attention has to be paid to formwork design using used pipe supports. Therefore, the present study results will be able to provide a firm base to prevent formwork collapses.

• 한국수소및신에너지학회논문집
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• 제8권3호
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• pp.137-141
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• 1997

The effects of Ag addition to Zr-based hydrogen storage alloys ($Zr_{0.7}Ti_{0.3}V_{0.4}Ni_{1.2}Mn_{0.4}$, $Zr_{0.7}Ti_{0.3}V_{0.4}Ni_{1.2}Mn_{0.3}Cr_{0.1}$ and $Zr_{0.6}Ti_{0.4}V_{0.4}Ni_{1.2}Mn_{0.3}Fe_{0.1}$) on the electrode properties were examined. Ag-free and Ag-added Ze-based alloys were prepared by arc melting, crushed mechanically, and subjected to the electrochemical measurement. In $Zr_{0.7}Ti_{0.3}V_{0.4}Ni_{1.2}Mn_{0.4}$ alloy, 0.08 wt% Ag addition to the alloy improved the activation rate. Also Ag addition improved both activation property and discharge capacity in $Zr_{0.7}Ti_{0.3}V_{0.4}Ni_{1.2}Mn_{0.3}Cr_{0.1}$. For these Ag-added alloys, discharge capacities with the change of charge-discharge current density(10mA, 15mA and 30mA) are almost constant. Showing very high rate capability, discharge capacity of $Zr_{0.6}Ti_{0.4}V_{0.4}Ni_{1.2}Mn_{0.3}Fe_{0.1}$ alloy increased by Ag addition to the alloy. When the amount of Ag addition in $Zr_{0.7}Ti_{0.3}V_{0.4}Ni_{1.2}Mn_{0.4}$ alloy increased too much, the electrode properties became worse. Unveiling mechanism of effect of Ag addition is now progressing in our laboratory.

• 한국환경생태학회지
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• 제18권4호
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• pp.456-464
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• 2004

KISTI(한국과학기술정보연구원)는 학회 업무 관리, 학술정보 관리를 학회가 어려움 없이 처리하도록 지원하고자, 학회 정보화 사업의 일환으로 학회 학술정보 유통체제 전 과정을 온라인화하고 쉽게 관리할 수 있도록 한 $\boxDr$KISTI-ACOMS(KISTI-Article COntribution Management System: KISTI-학회논문투고관리시스템)$\boxUl$을 개발하여 2001년부터 학회에 무상으로 보급하여 왔다. 최근 KISTI-ACOMS를 이용하고자 하는 학회의 요청이 더욱 확대되고 있어, KISTI는 많은 학회의 특성들을 의견수렴하여, KISTI-ACOMS의 표준화를 목표로 보완해 나가고 있다. 본 연구는 KISTI-ACOMS를 기반으로 구축한 한국환경생태학회의 학회논문투고관리시스템의 기능에 대해 살펴보고, 향후 시스템에 필요한 기능 및 명세를 기술함으로써 한국환경생태학회의 개선된 온라인논문투고관리시스템을 제시한다.

• Advances in materials Research
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• 제5권2호
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• pp.93-105
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• 2016

KNN-based ceramics modified with small amounts of $Bi_4Zr_3O_{12}$ (BiZ) has been synthesized using high-throughput experimentation (HTE). The results from X-ray diffraction show that for samples with base composition $(K_{0.5}Na_{0.5})NbO_3$ (KNN), the phase present changes from orthorhombic to pseudo-cubic with more than 0.2 mol% BiZ addition; for samples with base composition $(K_{0.48}Na_{0.48}Li_{0.04})(Nb_{0.9}Ta_{0.1})O_3$ (KNNLT), the phase present changes from a mixture of orthorhombic and tetragonal symmetry to pseudo-cubic with more than 0.4 mol % while for samples with base composition $(K_{0.48}Na_{0.48}Li_{0.04})(Nb_{0.86}Ta_{0.1}Sb_{0.04})O_3$ (KNNLST), the phase present is tetragonal with <0.3 mol% BiZ addition and transforms to pseudo-cubic with more dopant addition. The microstructures of the samples show that addition of BiZ decreases the average grain size and increases the volume of pores at the grain boundaries. The values of dielectric constant for KNN and KNNLT compositions increase slightly with BiZ addition while that for KNNLST decreases gradually with BiZ addition. The dielectric loss values are between 0.02 and 0.04 for KNNLT and KNNLST compositions while they are ~ 0.05 for KNN samples. The resistivity values increases with BiZ addition and values in the range of $10^{10}{\Omega}cm$ and $10^{12}{\Omega}cm$ are obtained. The piezoelectric charge coefficient ($d{^*}_{33}$) is highest for KNNLST samples and decreases gradually from ~400 pm/V to ~100 pm/V with BiZ addition.

• Journal of Information Science Theory and Practice
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• 제11권1호
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• pp.14-30
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• 2023

The purpose of this study is to compare research trends in the information and communication technology (ICT) field between North and South Korea and analyze the differences by using data mining. Frequency analysis, clustering, and network analysis were performed using keywords from seven South Korean and two North Korean ICT academic journals published for five years (2015-2019). In the case of South Korea (S. Korea), the frequency of research on image processing and wireless communication was high at 16.7% and 16.3%, respectively. North Korea (N. Korea) had a high frequency of research, in the order of 18.2% for image processing, 16.9% for computer/Internet applications/security, and 16.4% for industrial technology. N. Korea's natural language processing (NLP) sector was 11.9%, far higher than S. Korea's 0.7 percent. Student education is a unique subject that is not clustered in S. Korea. In order to promote exchanges between the two Koreas in the ICT field, the following specific policies are proposed. Joint research will be easily possible in the image processing sector, with the highest research rate in both Koreas. Technical cooperation of medical images is required. If S. Korea's high-quality image source is provided free of charge to N. Korea, research materials can be enriched. In the field of NLP, it calls for proposing exchanges such as holding a Korean language information conference, developing a Korean computer operating system. The field of student education encourages support for remote education contents and management know-how, as well as joint research on student remote evaluation.

• 한국지형학회지
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• 제28권1호
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• pp.101-114
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• 2021

Junior Ranger is a self-directed interpretation program for young visitors at national parks in the United States. The success of this program can be largely attributed to the role of an activity book which is given an applicant free of charge at a visitor center. This study aims to analyze the main characteristics of activity books for 14 national parks' Junior Ranger and to draw some implications for Korean geomorphological education. Although the activity books are varied in size, volume and printing, all of them offer diverse activities which are composed of different contents related to park resources in four fields and are performed in different ways such as Q&A, picture and word game, and creative activity. The time-consuming activities including attendance at a ranger-led program prevent the participant from making a superficial visit to be a junior ranger. The implications of the study are as follows: Firstly, the geomorphological education for children is needed to be strongly based on field experience learning and to be more carried out using a way of game rather than conventional Q&A, suggesting that it encourages students not to lose their interest for learning. Secondly, it is also necessary for the learning contents to be focused on various resources related to landform as well as landform itself. In addition, a creative activity such as writing verse or drawing feeling should be more applied to the geomorphological education in order to enhance their effects on affective domain beyond cognitive one. It is likely to be an alternative approach to understand landform by internalizing a sense of landform.

• 한국문헌정보학회지
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• 제48권2호
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• pp.89-107
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• 2014

본 연구의 목적은 공공도서관에서 이루어지고 있는 어린이 대상 독서프로그램의 효과를 정성적으로 분석하고 이를 바탕으로 독서프로그램의 성과 측정 영역을 개발하는 것이다. 이를 위해 '2013 도서관과 함께 책읽기' 사업에 참여하는 도서관의 독서프로그램 어린이들, 프로그램 담당자들과 면담 및 관찰을 하였고 독서프로그램의 효과를 분석하였다. 연구 결과 '도서관과 함께 책읽기' 프로그램에 참가한 어린이들은 대체로 긍정적인 변화를 보였으며 독서프로그램의 효과 측정 영역이 책 읽기와 책에 대한 태도, 도서관과 사서에 대한 인식, 독서프로그램의 참여도, 소리 내어 읽는 능력, 이야기를 듣고 이해하는 능력, 공격성, 자신의 감정표현 능력, 발표력, 집중력, 잠재력으로 나타났다. 또한 독서프로그램의 효과에 영향을 주는 요소로 사서의 적극적인 노력, 지역아동센터의 환경, 학년 구성, 강사의 수업 구성 방식, 독서프로그램에서 사용하는 책의 선정, 독서프로그램 참가 어린이의 독서능력 및 독서에 대한 관심, 자유시간의 제공 여부를 들 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.127-130
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• 2004

For the quality control of the industrial products, an automatic hole measuring system has been developed. The measurement device allows X-Y movement due to contact forces between a hole and its own circular cone and the device is attached to an industrial robot. Its measurement accuracy is about 0.04mm. This movement of the plate is measured by two LVDT sensor system. But this system using the LVDT sensors is restricted by high cost and precision of measurement and correspondence of environment so particularly, a vision system with CCD-Camera is discussed in this paper for the above mentioned purpose. The device consists of two of two links jointed with hinge pins basically and, they guarantee free movement of the touch prove attached on the second link in the same plane. These links are returned to home position by the spring plungers automatically after each process for the next one. On the surface of the touch prove, it has a circular white mark for camera recognition. The system detect and notify the center coordinate of capture mark image through the image processing. Its measuring accuracy has been proved to be about $\pm$0.01mm through the repeated implementation over 200 times. This technique will shows the advantage of touch-indirect image capture idea using cone-shaped touch prove in various symmetrical shaped holes particulary, like tapped holes, chamfered holes, etc As a result, we attained our object in a view of the accuracy, economical efficiency, and functionality