• 한국자기학회:학술대회 개요집
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• 한국자기학회 2009년도 정기총회 및 동계학술연구발표회
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• pp.192-192
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• 2009

Magnetic and magnetotransport properties of (1-x) $La_{0.7}Sr_{0.3}MnO_3-xRE_2O_3$ (RE=La, Nd) (x = 0.025, 0.05, 0.075, 0.1, 0.2, 0.3) composite polycrystalline samples were systematically studied. Samples were prepared using conventional solid-state reaction. LSMO and $RE_2O_3$ react at high temperature and become chemically compatible. The ferromagnetic-paramagnetic transition temperatures ($T_c$) of the LSMO-$Nd_2O_3$ composite samples were decreased 313K~349K with increasing x, while the $T_c$ values of the LSMO-$La_2O_3$ composite samples were almost unaltered in the range of 355K~358K, representing that the ferromagnetism of LSMO might be more seriously degraded by Nd substitution on the ($La_{0.7}Sr_{0.3}$) site. However, LSMO-$RE_2O_3$ composite samples exhibit greatly enhanced low field magnetoresistance (LFMR) and dMR/dH value without an appreciable increase in its resistivity. Remarkably improved LFMR properties are attributed to LSMO grain boundaries acting as effective spin-dependent scattering centers. The relationship among the $RE_2O_3$ addition, microstructure, magnetic and magnetotransport properties will be discussed in this paper.

• 한국식품위생안전성학회지
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• 제14권1호
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• pp.84-89
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• 1999

Octenylscuccinated corn starches prepared by reaction of corn starch with 1-octenylsuccinic anhydride(OSAn) and their degree of substitution (DS), reaction efficiency(RE), residual octenylsuccinic acid (OSA), and physicochemical properties were compared with those of the native corn starch. DS increased with increase of OSAn and RE was much nearly the same regardless of increased of OSAn. The content of residual of residual OSA was significantly lower than that of regulation of food additives. And as washing frequency of dispersion of the reactant was increased, the content of residual OSA of octenylsuccinated starch was decreased. Raid Visco-Analyzer initial pasting temperature and setback of octenylsuccinated starches decreased whereas peak viscosity and breakdown increased. When DS of octenylsuccinated starches increased, temperature of initial gelatinization of octenylscuccinated starches drastically decreased. The octenylsuccinated starches also formed clearer pastes. The solubility was much nearly the same regardless of increase of DS at 7$0^{\circ}C$ but the swelling power increased 1.2~1.7 times higher than that of native corn starch at 7$0^{\circ}C$. The water binding capacity of octenylsuccinated starches also decreased.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.19-20
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• 2018

For this study, a test was conducted on the basic polymer property depending on the replacement amount of polymer. The result showed that the flow of slump was increased with the increase of polymer replacement amount and an amount of air entraining. In addition, with a decrease of unit W/B, an amount of bleeding was reduced, and the first and final time for 6% replacement amount was found to be the fastest. This implies that replacement of more than 6% may affect the hydration of cement.

• ETRI Journal
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• 제37권5호
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• pp.1012-1022
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• 2015

Conventional cryptographic algorithms are not sufficient to protect secret keys and data in white-box environments, where an attacker has full visibility and control over an executing software code. For this reason, cryptographic algorithms have been redesigned to be resistant to white-box attacks. The first white-box AES (WB-AES) implementation was thought to provide reliable security in that all brute force attacks are infeasible even in white-box environments; however, this proved not to be the case. In particular, Billet and others presented a cryptanalysis of WB-AES with 230 time complexity, and Michiels and others generalized it for all substitution-linear transformation ciphers. Recently, a collision-based cryptanalysis was also reported. In this paper, we revisit Chow and others's first WB-AES implementation and present a conditional re-encoding method for cryptanalysis protection. The experimental results show that there is approximately a 57% increase in the memory requirement and a 20% increase in execution speed.

• Plant Breeding and Biotechnology
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• 제6권4호
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• pp.426-433
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• 2018

Plant tissue culture is a technique that has invariably been used for various purposes such as obtaining transgenic plants for crop improvement or functional analysis of genes. However, this process can be associated with a variety of genetic and epigenetic instabilities in regenerated plants, termed as somaclonal variation. In this study, we investigated mutation spectrum, chromosomal distributions of nucleotide substitution types of single-nucleotide polymorphisms (SNPs) and insertions/deletions (InDels) by whole genome re-sequencing between Dongjin and Nipponbare along with regenerated plants of Dongjin from different induction periods. Results indicated that molecular spectrum of mutations in regenerated rice against Dongjin genome ranged from $9.14{\times}10^{-5}$ to $1.37{\times}10^{-4}$ during one- to three-month callus inductions, while natural mutation rate between Dongjin and Nipponbare genomes was $6.97{\times}10^{-4}$. Non-random chromosome distribution of SNP and InDel was observed in both regenerants and Dongjin genomes, with the highest densities on chromosome 11. The transition to transversion ratio was 2.25 in common SNPs of regenerants against Dongjin genome with the highest C/T transition frequency, which was similar to that of Dongjin against Nipponbare genome.

• 한국정보통신학회논문지
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• 제9권1호
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• pp.128-133
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• 2005

클라이언트/서버 환경에서 컴퓨터의 성능을 측정하는 척도로써 주어진 작업에 대한 응답시간과 단위 시간 내의 얼마나 많은 작업들을 수행 완료할 수 있는가를 나타내는 처리율이 컴퓨터의 성능을 판단하는 지표로 사용되고 있다. 본 논문에서는 멀티미디어 서버에서 제한된 버퍼의 이용을 극대화하기 위해 상대적으로 작은 시간 간격으로 나누어 하나의 미디어 스트림을 버퍼에 할당/회수하는 윈도우 기반 버퍼 관리 기법을 제안하였다. 또한, 한번 사용된 데이터 블록에 대해 재 참조 시간을 계산하고 후속 스트림이 재사용할 수 있게 하여 멀티미디어 서버의 입출력 횟수를 줄일 수 있는 버퍼 교체 기법을 제안하였다.

• 한국동물학회지
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• 제35권1호
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• pp.80-86
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• 1992

The nucleotide sequences of 185 rRNAs of the five Korean decapods were partially determined by the direct sequencing method using the reverse transcriptase. ne average GC content of five species was 51.1% which is higher than that of yeast(45.0%) and lower than those of frog (53.0%) and rat (55.6%). This result follows the general patterns of the GC content in the nucleotides of the nucleic acid shown among the various phylogenetic groups. The average ratio of transrional/transversional nucleotide substitution of pairwise comparison among six species (including Anemia salina) was 1.200 $\pm$ 0.310 when whole region alas examined. However, the ratio showed some differences when the conservative regions and variable regions frere separatelv examined. The molecular phylogenies of the five species were constructed by using two different tree making methods. In general the results support the previously reported molecular phylogeny of the decapod crustaceans. However, our results indicate thats in the analysis of the sequence dat3, the UPGMA clustering method of the distance matrix method should be carefully employed after considering the rate of nucneotide substitution in the different regions of the molecule.

• 정보보호학회논문지
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• 제18권4호
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• pp.53-68
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• 2008

실용적인 프라이버시 보호 기술 중의 하나인 행렬 기반 랜덤화 기법에 대하여 세밀한 분석을 실시한다. 최적의 변환 행렬을 찾기 위한 프라이버시 손상 관점의 요구조건 및 정확성 측도로 제안된 행렬의 조건수 개념과 연관된 파라미터들간의 관계를 이론적으로 규명한다. 행렬 기반의 대표적 알고리즘인 랜덤 대치 기법의 효율적인 구현을 위하여 데이터 재구축 과정에서 필요한 역행렬을 간단히 구하는 공식을 제시하고, 행렬의 노름에 따른 변환 행렬의 조건수와 변환된 분포의 기댓값 및 분산을 계산함으로써 표준오차와 파라미터들 간의 관계식을 도출한다. 또한, 랜덤 대치 기법을 구현하여 다양한 시뮬레이션을 실시함으로써 이론적으로 얻은 결과를 실험적으로 검증한다.

• KSBB Journal
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• 제15권3호
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• pp.299-306
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• 2000

발광미생물 (luminescent bacteria)인 P. phosphoreum을 이용한 수계의 환경독성물질로 지정된 ethane, benzene, phenol류에 chlorine이 치환된 l47~의 독성강도를 생체발광의 50%저하시키 는 독성농도인 ECso값을 통한 생물학적 정량을 하였을 때 phenol) benzene) ethane 의 순서로 독성깅도가 높게 산출되 어졌으며, 특히 지환된 chlo괴ne의 수가 증가할수록 독성강도가 강하다는 것을 알 수 있었다. 또한 산출된 ECso값을 이용허여 독성물질들의 물려화학적 parameter특성인 octan이(water 분할계 수 (log P), 용해도 (log S) 및 solvatochromic parameter의 떤관쟁 을 QSAR 모탤링하였으며 실힘을 통하지 않고, 독성의 독성강도 를 예측할 수 있는 회기식을 다음과 같이 산출하였다. $log EC_{50} =2.48 + 0.914 log S(n=9 R2=85.5% RE=0.378) log EC_{50}=0.35 - 4.48 Vi/100 + 2.84 \pi^* +9.46{\beta}m-4.48am (n =14 R2=98.2% RE=0.012) log EC_{50} =2.64 -1.66 log P(n=5, R2=98.8% RE=0.16) log EC_{50}=3.44 -1.09 log P(n=9 R2= 80.8% Re=0.207)$. QSAR 모델은 QSAR 검증식을 통하여 확인된 다중회기식을 이용함으로 실험하지 않은 독성물 질이 갖는 물리화학적인 특성을 대입하여 log Eeso값을 예측할 수 있으므로 경제적, 시간적으로 이익을 얻을 수 있는 모델이다.

• 한국재료학회지
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• 제31권8호
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• pp.445-449
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• 2021

Zintl compound Mg₃Sb₂ is a promising candidate for efficient thermoelectric material due to its small band gap energy and characteristic electron-crystal phonon-glass behavior. Furthermore, this compound enables fine tuning of carrier concentration via chemical doping for optimizing thermoelectric performance. In this study, nominal compositions of Mg_3.8Sb_2-xTe_x (0 ≤ x ≤ 0.03) are synthesized through controlled melting and subsequent vacuum hot pressing method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) are carried out to investigate phase development and surface morphology during the process. It should be noted that 16 at. % of excessive Mg must be added to the system to compensate for the loss of Mg during melting process. Herein, thermoelectric properties such as Seebeck coefficient, electrical conductivity, and thermal conductivity are evaluated from low to high temperature regimes. The results show that Te substitution at Sb sites effectively tunes the majority carriers from holes to electrons, resulting in a transition from p to n-type. At 873 K, a peak ZT value of 0.27 is found for the specimen Mg_3.8Sb_1.99Te_0.01, indicating an improved ZT value over the intrinsic value.