• The Korean Journal of Ceramics
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• v.1 no.1
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• pp.40-44
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• 1995

Ethylammonium-layered aluminosilicates intercalates were prepared by ion exchange reaction between the layered silicates with different layer changes density of 0.32∼0.41 e per unit formula and ethylammonium chloride. A kinetic study on the thermal deintercalation of the ethylammonium-layered silicate intercalates was carried out by range of 350℃ to 480℃ (heating rate of 10℃/min). Based on the Ozawa's method, the activation energies of the thermal deintercalation reaction were estimated as 171.2∼133.0 kJ/mol, which increase linearly with the layer charge densities.

• Asia pacific journal of information systems
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• v.13 no.4
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• pp.171-189
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• 2003

The three main purposes of this paper are to (1) identify critical success factors(CSFs) for electronic commerce(EC), (2) investigate the explanatory power of these CSFs on firm performance, and (3) compare differences in evaluating CSFs and explaining impact of CSFs on performance among Korea, Japan, and U.S.A. EC firms. Through a literature review and interviews with managers in EC firms, a list of 16 CSFs consisting of 111 items was compiled. In the second stage, questionnaires were administered to managers of EC companies in Seoul, Korea, Tokyo, Japan, and Texas, U.S.A. Survey results show that CSFs have very significant explanatory power for firm performance in Korea, Japan, and U.S.A. While security, privacy, technical expertise, information about goods/services, and variety of goods/services are the most explanatory CSFs in Korea and Japan, evaluation of EC operations, technical expertise, and ease of use show most explanatory power in U.S.A. In general, respondents in Korean and Japan evaluate CSFs quite differently compared to U.S.A counterparts.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.3 s.180
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• pp.171-178
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• 2006

The sonication mettled is widely used with surfactants to suspend individual single-walled carbon nanotubes in solution, and it is well known that sonication-induced tube cutting occurs. Recently, it is found out that ultrasonicated nanotubes yield simultaneous separation by tube length and diameter. Nanotubes that have been cut shortest possess the greatest enrichments of large-diameter species. In this study, single-walled carbon nanotubes are cut using a ball milling method. Similar fracture behavior is observed fur the ball milled nanotubes: i.e., large diameter tubes are cut shorter. The ability to separate carbon nanotubes by diameter and length will contribute to tile development of nanotube-based applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.168-171
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• 2000

Underwater acoustic communications have made considerable advances in the past decade. The purpose of this paper is to achieve the underwater communication by ultrasonic sensors and to investigate conditions of good underwater acoustic communicators. As a result of this experiments, the ultrasonic sensors, MA40E7R/S, made by Nicera can be used as ultrasonic transducers for underwater communication using AM(Amplitude Modulation) signal and Transmission Loss is 17.328[dB] at 65[cm]. To make a good underwater communicator, proper diameter of disk PZT transduers is the one of most important factors, because radiation of acoustic wave depends on proper diameter of transduers and the transmission loss strongly depends on the spreading loss.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.53 no.4
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• pp.171-174
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• 2004

The $Ag_2Te$ crystal was grown by the Bridgman method. The $Ag_2Te$ crystal was an monoclinic structure with lattice constance a = $8.1686{\AA}$, b = $9.0425{\AA}$, c = $8.0065{\AA}$. Hall effect shows a n-type conductivity in the $Ag_2Te$ crystal. The electrical resistivity was 1.080e-$3{\Omega}cm$ and electron mobility was $-5.48{\times}10^3cm^2/V{\cdot}sec$ at room temperature(RT).

• Journal of Chest Surgery
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• v.16 no.1
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• pp.171-175
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• 1983

The authors made a clinical study of 107 cases of empyema who were treated at Department of Thoracic Surgery of Chungnam National University Hospital during the period of Jan. 1976 through Aug. 1982 and compared the empyema of infant and children with that of adults. Following was the remits: 1. Male was predominant to female with the ratio of 2.5 to 1 and adult to infant was 2.6 to 1. 2. The cardinal symptoms were dyspnea, coughing, chest pain and fever. 3. Positive remit of bacteriological culture study was reported in 57% and the most common causative organism was staphylococcus in infant and childhood, E. coil in adult. 4. Most frequent predisposing factors of thoracic empyema in infant and childhood was pneumonia [53%], and in adult was pulmonary tuberculosis [40%]. 5. Treatment were combined with antibiotics therapy and several surgical procedures for empyema. 24 cases [22.4%] required open thoracotomy. 6. The mortality rate was 7.4% [8/107]. 86 cases [80.4%] were discharged with recovery and improvement.

• Journal of the Korean Operations Research and Management Science Society
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• v.23 no.4
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• pp.171-186
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• 1998

While one main stream of research in GDSS (Group Decision Support System) is to investigate how GDSS affects decision-making performances of groups according to task types, support features, meeting facilitation modes and meeting environments. little study h3s been done about how group characteristics affect group decision processes and outcomes depending upon GDSS is provided or not. So far, most GDSS research has considered group characteristics (e.g. personality homogeneity) as given and did not include it as control variables in experiments. Therefore, the objective of this study is to investigate how members of two different groups perceive the use of GDSS in group meetings through lab experiments. The two groups are homogeneous and heterogeneous groups in terms of members' personality mix. This research found that the effect of GDSS is a function of groups' personality homogeneity in regards of the satisfaction on decision process and the communication thoroughness. The support of GDSS and the group homogeneity are proved to influence participant's perception about some dependent variables such as satisfaction on decision process.

• Steel and Composite Structures
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• v.14 no.2
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• pp.155-171
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• 2013

This study analytically evaluated the seismic performance of wind-designed diagrid tall steel buildings in regions of moderate/low seismicity and strong winds. To this end, diagrid tall steel buildings with varying wind exposure and slenderness ratio (building height-to-width ratio) conditions were designed to satisfy the wind serviceability criteria specified in the Korean Building Code and the National Building Code of Canada. A series of seismic analyses were then performed for earthquakes having 43- and 2475- year return periods utilizing the design guidelines of tall buildings. The analyses demonstrated the good seismic performance of these wind-designed diagrid tall steel buildings, which arises because significant overstrength of the diagrid system occurs in the wind design procedure. Also, analysis showed that the elastic seismic design process of diagrid tall steel buildings might be accepted based on some wind exposures and slenderness ratios.

• Proceedings of the Korean Society for Information Management Conference
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• 2010.08a
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• pp.171-176
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• 2010

이 연구는 그동안 밝혀지지 않았던 꼴레쥬드 프랑스에 소장된 한국 고문헌을 실사(實事)하여 소장본의 규모와 전래경위, 자료적 특징을 살피는 것을 목적으로 하였다. 특히, 구한말 한국 고문헌의 현황과 프랑스 내 한국 고문헌 소재파악의 중요한 참고문헌인 "한국서지(Bibliographie Coreenne)"를 저술한 모리스 꾸랑(Maurice Courant, 1865-1935) 개인 소장본과 꼴레쥬드 프랑스 소장본과의 관계를 규명하였다. 이를 통하여 국외 한국 문화재의 기초조사에 일조를 하고자 하며 향후 활용방안을 모색해 보고자 한다.

• Journal of Korea Technology Innovation Society
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• v.4 no.2
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• pp.157-171
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• 2001

This paper discusses the economics of local loop architecture focusing on existing technologies, ADSL, HFC, and new one, PLC, and suggests a new modeling approach of access network system and the numerical equations. To modelize access network system and drive the numerical equations, we consider the double star and the tree & branch architecture and made block diagram of each access system. In addition, we introduce the density of subscriber as a variable and the equation of seeking the optimal number of cell in a service area. The economics of local loop architecture is analyzed in two ways, i.e. with and without consideration of the cost of cable and infrastructure. From the numerical analysis, we find that in case of not including the cost of cable and infrastructure, there is no much difference in the cost per one subscriber, while, in case of including it, there is remarkable difference among technologies. Therefore we conclude that the economics of local loop architecture is depend on the density of subscriber and existing network infrastructures.