• Composites Research
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• v.17 no.5
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• pp.47-53
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• 2004

In this work, two thermal latent catalysts, i.e., N-benzylpyrazinium hexafluoroantimonate (BPH) and benzyl-2,5-dimethylpyrazinium hexafluoroantimonate (BDPH), were synthesized. The cure behaviors and thermal stabilities of diglycidylether of bisphenol A (DCEBA) epoxy resins initiated by 1 wt.% of the catalysts were investigated by DSC, NIR, TCA, and DMA Latent properties of the catalysts were examined by conversion of epoxy resins using NIR from $100^{\circ}C$ to $180^{\circ}C$ From the resultes of near-IR, DGEBA/BPH system showed higher conversion than that of DGEBA/BDPH system. The thermal stabilities of DGEBA/BDPH system based on the initial decomposition temperature (IDT) and integral procedural decomposition (IPDT) were relatively lower than those of DCEBA/BPH system. These could be attributed to the hindered structure of BDPH, resulting in decreasing the thermal stability in the DGEBA/BDPH system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.947-954
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• 2014

In general, Fracture of the material is not occurring of the maximum normal stress or the maximum shear stress failure in the state. Maximum normal stress and maximum shear stress in the state of Critical coupling from being destroyed based on the Mohr-Coulomb theory. Couple of different mixtures, including permeable asphalt pavement, SMA and dense-graded asphalt mixture, were used for compression triaxial test at $45^{\circ}C$ and $60^{\circ}C$. Mohr-Coulomb theory to the analysis of compression triaxial test result of the internal friction angle $38.9^{\circ}{\sim}46.9^{\circ}$ measured somewhat irregularly, but in the case of cohesion, depending on whether the temperature and immersion of the specimen appeared differently. In addition, Indirect tensile test and compression triaxial test of the asphalt mixture to determine the correlation between compression triaxial test results assessed as cohesion and internal friction angle calculated using the theoretical Indirect tensile strength and measured indirectly tensile strength were analyzed. The Measured & Predicted IDT St values tended to be proportional.

• Polymer(Korea)
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• v.26 no.4
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• pp.501-507
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• 2002

In this work, diglycidylether of bisphenol-S (DGEBS) epoxy resin was prepared by alkaline condensation of bisphenol-S (BPS) with epichlorohydrin (ECH) in the presence of NaOH catalyst. The structure of the synthesized DGEBS epoxy resin was confirmed by IR, NMR spectra, and elemental analysis. The curing reaction and glass transition temperature ($T_g$) of DGEBS epoxy resin cured with phthalic anhydride (PA) and tetrahydrophthalic anhydride (THPA) at curing agents were studied by dynamic differential scanning calorimetry (DSC). The thermal stability of the cured specimen was investigated by thermogravimetric analysis (TGA). As a result, the activation energy ($E_a$) of DGEBS/PA system was higher than that of DGEBS/THPA system, whereas $T_g$, initial decomposed temperature (IDT), and decomposition activation energy ($E_t$) of DGEBS/PA were lower than those of DGEBS/THPA. This was probably due to the fact that the crosslinking density of DGEBS/THPA was increased by ring strain of curing agent.

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.2
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• pp.97-116
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• 2004

Recently, e portion of on-line stock brokerage has been rapidly increased to be more than 50%, on the basis of contracted money. The usage of wCTS(Web Based Cyber Trading Systems) has now got into the steady state over the initial diffusion stage, which means wCTS has got more-than-half customer base in on-line service. Therefore, brokerage service providers have their competitive strategic focus on customer retention through the enhancement of customer loyalty. This study provides framework and survey results on explanation of wCTS user's loyalty, what and how factors affect wCTS user's loyalty. We adopt the results of early studies on information technology acceptance and diffusion such as TAM(Technology Acceptance Model) and IDT(Innovation Diffusion Theory). We also referred loyalty theory of marketing area and studios on CTS usage. We categorized explanation factors as three groups characteristics of users, characteristics of system, social environment. And we assumed that these three factors could affect the loyalty through two parameters : customer satisfaction and trust to the system. This study firstly shows that the ease of use and usefulness, the major factors of TAM. can also be applied to the loyalty of wCTS with resulting that the usefulness is more important than the ease of use In wCTS. Secondly, it shows that the innovative and risk-sensitive user has the lower degree of loyalty. Thirdly, it shows that the satisfaction and trust impact the loyalty simultaneously, the trust particularly impacts more strongly than the loyalty, due to the characteristics of monetary transaction in wCTS. This study provides meaningful results to the other on-line EC service fields as a first empirical research regarding the loyalty to wCTS which is a typical on-line EC service.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.2 s.9
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• pp.89-97
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• 2003

Indirect tensile strength(IDT) test and resilient modulus(Mr) test were performed to evaluate experimental performance characteristics for the conventional and crumb rubber-modified(CRM) asphalt concrete using dry and wet processes asphalt. The IDT test was conducted under three temperatures(5, 10, 20$^{\circ}C$). According to the test results, it was shown that indirect tensile strength of CRM asphalt concrete was lower than that of the conventional one. However, toughness and maximum vortical strain of the CRM asphalt concrete were higher than those of the conventional one. The results of Mr test were presented that Mr of CRM asphalt concrete was higher than that of the conventional one. In addition, it was revealed that the overall laboratory performance characteristics of the wet-processed CRM asphalt concrete was better than those of the dry-processed one.

• Korean Journal of Crystallography
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• v.7 no.2
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• pp.175-182
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• 1996

ZnO thin films were deposited on Corning 7059 glass substrates to study fundamental properties of films. According to the experimental results, (002) preferred ZnO thin films were grown by purging Ar/O2 mixed gas, but not without oxygen gas. The structure and the orientation of ZnO thin films were much affected by the substrate temperature and rf power. High quality ZnO films were obtained by increasing their values. Optimum deposition parameters were : 300W rf power, 300℃ substrate temperature, Ar/O2=70/30. To characterize SAW propagation properties, IDT was fabricated by etching Al films deposited on diamond/Si wafer with RIE. Measured λ(wavelength) was 24μm and experimental results were well matched with simulation. Center frequency was 250MHz, and the calculated phase velocity of ZnO/ diamond structure was about 6000m/s.

• Polymer(Korea)
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• v.27 no.1
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• pp.33-39
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• 2003

In this study, the bisphenol-based DGEBA/GEBS blend systems were studied in cure kinetics, thermal stabilities, and fracture toughness of the casting specimen. The content of DGEBA/DCEBS was varied in 100 : 0, 90 : 10, 80 : 20, 70 : 30, and 60 : 40 wt%. The cure activation energies ($E_a$) of the blend systems were determined by Ozawa's equation. The thermal stabilities, including initial decomposed temperature (IDT), temperatures of maximum rate of degradation ($T_{max}$), and integral procedural decomposition temperature (IPDT) of the cured specimen were investigated by thermogravimetric analysis (TGA). For the mechanical interfacial properties of the specimens, the critical stress intensity factor ($K_{IC}$) test was performed and their fractured surfaces were examined by using a scanning electron microscope (SEM). As a result, $E_a$, IPDT, and $K_{IC}$ show maximum values in the 20 wt% DGEBS content compared with the neat DGEBA resins. This was probably due to the fact that the elevated networks were farmed by the introduction of sulfonyl groups of the DCEBS resin.

• The KIPS Transactions:PartC
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• v.18C no.3
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• pp.157-166
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• 2011

The virtualization layer is executed in higher authority layer than kernel layer and suitable for monitoring operating systems. However, existing virtualization monitoring systems provide simple information about the usage rate of CPU or memory. In this paper, the monitoring system using full virtualization technique is proposed, which can monitor virtual machine's dynamic kernel object as memory, register, GDT, IDT and system call table. To verify the monitoring system, the proposed system was implemented based on KVM(Kernel-based Virtual Machine) with full virtualization that is directly applied to linux kernel without any modification. The proposed system consists of KvmAccess module to access KVM's internal object and API to provide other external modules with monitoring result. In experiments, the CPU utilization for monitoring operations in the proposed monitering system is 0.35% when the system is monitored with 1-second period. The proposed monitoring system has a little performance degradation.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.64.3-65
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• 2021

인공지능 기계학습에 의한 한문고전 자동번역기는 승정원일기 뿐만 아니라, 한국 고문헌 중 천문 기록에 특화되어 한자로 된 천문 고전을 한글로 번역해 서비스하고 있다. 한국천문연구원은 한국지능정보사회진흥원이 주관하는 2019년도 Information and Communication Technology 기반 공공서비스 촉진사업에 한국고전번역원과 공동 참여하여 이 자동 번역기 개발을 완료한 것이다. 이 번역기의 개발 목적은 초벌 번역 수준일지라도 문장 형태의 한문을 한글로 자동 번역하는 것이며, 이 연구는 현재 번역기 운용 현황을 서비스 별로 분석하고자 한다. 자동 번역관련 서비스는 크게 3가지이다. 첫째, 누구나 웹 접속을 통해 사용 가능한 한문고전 자동번역 대국민 서비스이다. 1년간 자체 시험을 거쳐 2021년 1월 12일 시험판을 오픈하여 운용 중에 있다. 둘째, 기관별로 구축된 코퍼스와 도메인 특화된 번역 모델 등을 관리할 수 있는 한문고전 자동번역 확산 플랫폼 서비스이다. 대국민 서비스와 함께 클라우드 기반으로 서비스되며, 한국고전번역원이 관리를 담당한다. 셋째, 자동번역 Applied Programmable Interface를 활용한 한국천문연구원 내 자체 활용이 가능한 천문고전 자동번역 서비스이다. 서비스 현황 분석은 기관별 관리 서비스에 해당되는 한문고전 자동번역 확산 플랫폼에서 집계하여 제공하는 대시보드의 통계 기능을 활용한다. 각 서비스별 문장과 파일 번역 이용 건수, 번역 속도, 평균 자수 뿐만 아니라, 번역 모델 프로필에 따른 이용률 분석이 가능하다. 이에 따른 주요 분석 중 하나인 올해 전체 번역 이용 건수는 한 해 각 기관의 평균 방문자수 대비 87% 성과 목표에 해당되는 약 38만 건에 근접할 것으로 예측된다. 이 자동 번역기는 원문 해독 시간을 단축시키는 효과와 함께 미번역 천문 고문헌의 활용성을 높여 다양한 연구에 기여할 것이다.

• Korean Journal of Materials Research
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• v.6 no.3
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• pp.341-346
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• 1996

R-sapphire 기판위에 rf magnetron 스퍼터 방법으로 ZnO 박막을 증착하여 박막의 증착변수에 따른 결정성장방향과 SAW 특성을 분석하였다. 증착온도, 압력, rf 전력에 의해 박막 성장면이 (002)에서 (110)으로의 전이가 관찰되었다. 5mTorr, 40$0^{\circ}C$, 250W의 rf 전력에서 가장 우수한 (110)방향의 에피 ZnO 압전 박막의 SAW 특성을 분석하기 위하여 제작된 마스크를 사용하여 IDT를 구성한 후 SAW 특성을 분석한 결과 h/λ=0.08의 조건에서 전단속도가 약 5232m/s로서 고주파용 SAW 필터의 제조에 적합한 특성을 보이고 있다.