• Journal of the Korean Ceramic Society
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• 제28권12호
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• pp.969-974
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• 1991

The influences of A(Cu1/3Nb2/3)O3(A=Pb, Ba and Sr) on the ferroelectric-paraelectric phase transition of BaTiO3 ceramics has been investigated. The tetragonality of crystal structure decreased with increasing A(Cu1/3Nb2/3)O3 content at room temperature. A linear correlation between Curie point and the tetragonality of lattice was not observed. In all three systems the variation of Curie point with the mole fraction showed similar tendency that the Curie point decreased at lower mole fraction but gradually increased in the region of higher mole fractions, Diffuse phase transitions were observed at higher mole fractions. The variation of Curie points could be explained by internal stress and Jahn-Teller distortion of BO6 due to Cu2+, and it was thought that the diffuse character of phase transition was caused by compositional fluctuation.

• International Journal of Internet, Broadcasting and Communication
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• 제10권3호
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• pp.11-25
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• 2018

While being believed that decrypting any RSA ciphertext is as hard as factorizing the RSA modulus, it was also shown that, if additional information is available, breaking the RSA cryptosystem may be much easier than factoring. For example, Coppersmith showed that, given the 1/2 fraction of the least or the most significant bits of one of two RSA primes, one can factorize the RSA modulus very efficiently, using the lattice-based technique. More recently, introducing the so called cold boot attack, Halderman et al. showed that one can recover cryptographic keys from a decayed DRAM image. And, following up this result, Heninger and Shacham presented a polynomial-time attack which, given 0.27-fraction of the RSA private key of the form (p, q, d, $d_p$, $d_q$), can recover the whole key, provided that the given bits are uniformly distributed. And, based on the work of Heninger and Shacham, this paper presents a different approach for recovering RSA private key bits from decayed key information, under the assumption that some random portion of the private key bits is known. More precisely, we present the algorithm of recovering RSA private key bits from erased key material and elaborate the formula of describing the number of partially-recovered RSA private key candidates in terms of the given erasure rate. Then, the result is justified by some extensive experiments.

• Journal of the Korean Ceramic Society
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• 제32권3호
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• pp.289-294
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• 1995

As the results of the study on the effects of mixing time for raw materials to the electric and magnetic properties of Mg-ferrite, the fraction of spinel phase after calcination and the geometry density of sintered Mg-ferrite increased from 30% to 100% and from 2.5g/cc to 4.25g/cc respectively due to mixing-homobenity of raw materials. The AC resistivity of grains decreased and lattice parameter, saturation magnetization increased due to the increase in Fe+2 of sintered body. conclusively the characteristic of powder after calcination had strong influence on the microstructure, electric, and magnetic properties in Mg-ferrite sintered body.

• Food Science and Biotechnology
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• 제17권5호
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• pp.895-898
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• 2008

The mobility of water in set yogurt during fermentation was studied using nuclear magnetic resonance (NMR) relaxometry. The spin-spin relaxation was analyzed using a 2-fraction model, resulting in 2 spin-spin relaxation time constants $T_{21}$ and $T_{22}$. Both $T_{21}$ and $T_{22}$ exhibited rapid changes between 2 and 4 hr of fermentation, coinciding with the drop in pH and the rise in lactic acid bacteria count. The spin-lattice relaxation time $T_1$ increased over the fermentation period. Both $T_1$ and $T_2$ showed an increase in the mobility of water upon gel formation during fermentation. Water redistribution within the gel matrix due to casein aggregation and structure forming may be responsible for the changes in mobility.

• Journal of the Korean Society for Precision Engineering
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• 제22권12호
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• pp.170-174
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• 2005

A numerical system to extract effective elastic properties of polycrystalline thin-films for MEMS devices is developed. In this system, the statistical model based on lattice system is used for modeling the microstructure evolution simulation and the key kinetics parameters of given micrograph, grain distributions and deposition process can be extracted by inverse method proposed in the system. In this work, effects of kinetics parameters on the extraction of effective elastic properties of polycrystalline thin-films are studied by using statistical method. Effects of the fraction of the potential site($f_p$) among the parameters for deposition process of microstructure on the extraction of effective elastic properties of polycrystalline thin-films are investigated. For this research, polysilicon is applied to this system as the polycrystalline thin-films.

• Proceedings of the Korean Nuclear Society Conference
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• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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• pp.45-50
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• 1997

The conventional MOX fuel shows adverse controllability in view of its neutronic characteristics such as decreased soluble boron worth and effective delayed-neutron fraction compared to the UO$_2$ fuel. In order to mitigate these disadvantages, we devised a new concept of the hybrid UO$_2$-MOX fuel pellet with dual structure such that its outer annular section contains. UO$_2$ fuel and its inner cylindrical bar contains MOX fuel. The lattice physics code HELIOS was used to evaluate the neutronic characteristics of three different types of fuel pellets ; UO$_2$ fuel pellet, MOX fuel pellet, and hybrid UO$_2$-MOX fuel pellet. Results show that the hybrid UO$_2$-MOX fuel pellet generally has intermediate neutronic tendency between UO$_2$ fuel and MOX which could diminish the problems arising from the use of the conventional MOX fuel.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.50-54
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• 2004

A numerical system to extract effective elastic properties of polycrystalline thin-films for MEMS devices is already developed. In this system, the statistical model based on lattice system is used for modeling the microstructure evolution simulation and the key kinetics parameters of given micrograph, grain distributions and deposition process can be extracted by inverse method proposed in the system. In this work, the effects of kinetics parameters on the extraction of effective elastic properties of polycrystalline thin-films are studied by using statistical method. The effects of the fraction of the potential site( $f_{P}$ ) and the nucleation probability( $P_{N}$ ) among the parameters for deposition process of microstructure on the extraction of effective elastic properties of polycrystalline thin-films are studied.d.d.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제26권6호
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• pp.434-440
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• 2013

With polymer properties and ceramic volume fraction as design variables, the optimal structure of 1-3 piezocomposites has been determined to maximize the thickness mode electromechanical coupling factor. When the piezocomposite vibrates in a thickness mode, inter-pillar resonant modes are likely to occur between lattice-structured piezoceramic pillars and polymer matrix, which significantly deteriorates the performance of the piezocomposite. In this work, a new method to design the structure of the 1-3 type piezocomposite is proposed to maximize the thickness mode electromechanical coupling factor while preventing the occurrence of the inter-pillar modes. Genetic algorithm was used for the optimal design, and the finite element analysis method was used for the analysis of the inter-pillar mode.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제14권1호
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• pp.48-53
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• 2001

The crystal structure of ZnS fabricated by gas-liquid phase reaction was refined by the Rietveld program using X-ray diffraction data. The R-weighted pattern (R$\sub$wp/) of ZnS powder was 10.85%. The fraction of HCP phase was closely related with extra amount of H$_2$S gas. The lattice parameters and crystalline size were changed by the relative ratio of multi-phase. The luminescence property of ZnS:Cu, Al green phosphors prepared by conventional methods was good in the range of 91∼94% and 150∼190${\AA}$, respectively. According to the maximum entropy electron density(MEED) methods, any defects in (001) plane of cubic phase were not found. We suggest that both the Rietveld and maximum entropy density methods may be useful tools for studying luminescence mechanism of other phosphors materials.

• Proceedings of the Korean Society For Composite Materials Conference
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• 한국복합재료학회 2004년도 추계학술발표대회 논문집
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• pp.19-22
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• 2004

A numerical system to extract effective elastic properties of polycrystalline thin-films for MEMS devices is already developed. In this system, the statistical model based on lattice system is used for modeling the microstructure evolution simulation and the key kinetics parameters of given micrograph, grain distributions and deposition process can be extracted by inverse method proposed in the system. In this work, the effective elastic properties of polysilicon, $BaTiO_3\;and\;ZrTiO_4$ are extracted using this system and by employing the fraction of the potential site($f_P$) as a kinetics parameter for the microstructure evolution, the statistical tendency of these materials is studied.