3,476 research outputs found
Implementing the External Credit Assessment Institution of the Basel II Accord in Korea
No full textCHAPTER 11. Implementing the External Credit Assessment Institution of the Basel II Accord in Korea
(Kyung-Mook Lim and Hyeon-Wook Kim)
1 Introduction
2 BASEL II and the Role of the External Credit Rating Institutions
3 Credit Rating Agencies in Korea
4 Issues on the Recognition of the ECAI in Korea
5 Concluding Remarks
Comments(Chang Ho Han)TRU
Synthesis of new nanoporous carbon materials using nanostructured silica materials as templates
No full textIn this review, we summarize recent reports on the synthesis of various nanoporous carbon materials. Many nanoporous carbon materials having variable pore sizes and pore structures have been synthesized using appropriate nanostructured silica materials as templates. Nanoporous carbons with high pore volumes and uniform pore sizes have been produced using silica sol and silica gel as templates. Mesoporous carbons with several different pore structures have been synthesized using mesoporous silica materials such as MCM-48, HMS, SBA-15, MSU, and MCF as templates. Some of these nanoporous carbon materials were successfully used as adsorbents for bulky pollutants and electrodes for, supercapacitors and fuel cells.Y
Spin-coupling-induced Improper Polarizations and Latent Magnetization in Multiferroic BiFeO3
No full textMultiferroic BiFeO3 (BFO) that exhibits a gigantic off-centering polarization (OCP) is the most extensively studied material among all multiferroics. In addition to this gigantic OCP, the BFO having R3c structural symmetry is expected to exhibit a couple of parasitic improper polarizations owing to coexisting spin-polarization coupling mechanisms. However, these improper polarizations are not yet theoretically quantified. Herein, we show that there exist two distinct spin-coupling-induced improper polarizations in the R3c BFO on the basis of the Landau-Lifshitz-Ginzburg theory: Delta P-LF arising from the Lifshitz gradient coupling in a cycloidal spin-density wave, and Delta P-ms originating from the biquadratic magnetostrictive interaction. With the help of ab initio calculations, we have numerically evaluated magnitudes of these improper polarizations, in addition to the estimate of all three relevant coupling constants. We further predict that the magnetic susceptibility increases substantially upon the transition from the bulk R3c BFO to the homogeneous canted spin state in a constrained epitaxial film, which satisfactorily accounts for the experimental observation. The present study will help us understand the magnetoelectric coupling and shed light on design of BFO-based materials with improved multiferroic properties.11Ysciescopu
스틸렌계 블럭 공중합체를 이용한 IPN의 합성 및 특성에 관한 연구
No full text학위논문(박사) - 한국과학기술원 : 신소재공학과, 1997.2, [ xiii, 158 p. ]In the present work, synthesis and characteristics of the interpenetrating polymer networks(IPN``s) based on styrenic triblock copolymer has been studied. For the preparation of IPN, styrenic copolymers, polystyrene-polybutadiene-polystyrene(SBS) and polystyrene-poly(ethylene buthylene)-polystyrene(SEBS), were dissolved into the mixture of methyl methacrylate(MMA) and n-butyl acrylate(n-BA), or styrene monomer respectively. 3 mol\% of ethylene glycol dimethacrylate(EGDMA) or 1.5 mol% divinyl benzene(DVB)was used as a crosslinking agent and 1 wt% 2,2``-azobisisobutyronitrile(AIBN) was used as a initiator. Reaction temperature was kept at 60℃. Common solvent was used to know the influence of the presence of cosolvent during reaction, and toluene was selected as a cosolvent via swelling test. Corresponding semi-IPN, synthesized without crosslinking agent, of the same polymer composition was also evaluated for comparison. To characterize the IPN``s, phase separation behavior, dynamic mechanical and tensile properties were examined as well as the investigation of morphology by TEM.
The conversion of P(MMA-co-nBA) during the synthesis of IPN decreased by the presence of cosolvent in reaction medium and by increasing SBS concentration. Cloud conversion at the onset of phase separation was found to be higher in IPN than in semi-IPN and increased by the cosolvent. The phase separation mechanism during reaction was thought to be the spinodal decomposition through the light scattering measurement and morphology investigation using TEM. For the SBS/P(MMA-co-nBA) IPN, SBS appeared to be more continuous because of the low concentration of polyacrylate when the phase separation begins. Domain size increased by the presence of cosolvent and by decreasing of SBS content. From the dynamic mechanical behavior, two Tg peaks moved toward each other depending on the SBS concentration, which implied the improved intermixing. For the SEBS/P(MMA-co-nBA) IPN, spinodal structure was o...한국과학기술원 : 신소재공학과
A Decision Model for Investment Timing Using Real Options Approach
No full textThis article is confirmed to be submitted through the review and edition of the Korean Operations Research and Management Science Society. Please enter the title (Journal/Proceedings), volume, number, and pages properly when citing the article.Real options approach has recently received growing attentions in the research on business and technology management. Despite the applicability of the approach, it gained much momentum in practice. This paper addresses a problem of deciding the optimal investment time as the uncertainty resolves over time. The optimal timing for investment decisions was formulated, and the characteristics of the optimal decision were identified
Comprehensive Understanding of the HZO-based n/pFeFET Operation and Device Performance Enhancement Strategy
No full textWe report a comprehensive understanding of HZO-based n/pFeFET operation using (double-pulsed) quasi-static CV and pulsed IV techniques, providing the true nonvolatile polarization and excess trap density, which has not been reported yet. Also, we conceived new insight into the trapped charge and polarization switching by the method, based on the asymmetry of electron/hole trapping in n/pFeFET. Through the analysis, we propose a new erasing operation, resulting in enhanced performance (ex. endurance > 10^{10} cycles), and also proposed physical models of the n/pFeFET operation
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