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잡초성벼의 superoxide dismutase cDNA cloning과 재배벼로의 형질전환
박상규,박종석,이승인,서석철,김병극,조윤래,서학수 한국환경농학회 2002 한국환경농학회지 Vol.21 No.2
냉해나 한발등의 환경스트레스에 대해 저항성을 유발하는 유전자를 환경스트레스에 강한 잡초성벼로부터 선발하고 이들 유전자를 재배벼에 도입하여 도입유전자 산물의 과량 발현을 통해 냉해나 한발 등에 대한 저항성이 향상된 벼를 선발하고자 하였다. 잡초성벼인 Bhutan 14Ad로부터 냉해 및 한발 저항성 유전자로 알려진 superoxide dismutase (SOD) cDNA를 분리하고자 mRNA를 분리하고 이 분리된 mRNA를 이용해 reverse transcriptase PCR방법으로 SOD cDNA를 cloning 하였다. 그 결과 2종의 SOD cDNA가 cloning되어 SOD-A, SOD-B로 명명하였다. 이들 cDNA의 염기서열을 결정한 결과 이들은 아미노산 서열 상동성이 88.4%를 나타내었으며, SOD-A는 oryza sativa 계열의 Cu/Zn SOD유전자인 GenBank accession No. L36320와 99.3%로 동일하였으며, SOD-B는 accession No. D01000과 100% 동일하였다. 이들 SOD-A와 SOD-B cDNA를 재배벼인 낙동벼에 형질전환하여 형질전환체 벼를 선발하였으며, 이들 형질전환체 벼의 냉해저항성 및 한발저항성 검정을 통해 저항성이 향상된 형질전환체 벼를 선발하고 있다. Two different cDNA clones for superoxide dismutase (SOD) were isolated from an weedy rice variety (Oryza sativa, cv. Bhutanl4Ad) and were introduced into a cultivated rice variety (Oryza sativa, cv. Nakdong) in order to develop the environmental stress-resistant rice plants. Sequence analysis of the cloned cDNAs indicated that the deduced amino acid sequence of SOD-A is 88.4% identical to that of SOD-B. Furthermore, the nucleotide sequence of SOD-A is 99.3% identical to that of a Cu/Zn SOD gene of Oryza sativa (GenBank accession No. L36320). The nucleotide sequence of SOD-B was identical to that of the previously published SOD gene (Accession No. D01000). A cultivated rice variety, Nakdong-byeo, was transformed with chimenc SOD genes containing a actin promoter of rice and pin2 terminator using a particle bombardment technique. Transformed calli were selected on an selection medium containing phosphinothricin (PPT). Transgenic rice plants were regenerated from the PPT-resistant calli. PCR analysis with genomic DNAs from transgenic plants revealed that transgenes are introduced into rice genome.
黃正儀,鄭倧在,車星極 慶北大學校 文理科大學 1978 文理學叢 Vol.5 No.-
The stick antimony electrode has advantage of simplicity in measuring pH. Its field of application has been very wide in industrial and medical part. But its accuracy, sensitivity and reproducibility are somewhat poorer than those of glass electrode. In this study this electrode was applied in determining pH of the solution at various temperatures (15∼30℃) under high pressures (1∼2,500 bars). The emf(E) of the cell, Sb(Sb_2O_3/ HCl(aq.) /AgCl/ Ag, was messured and plotted against pH. In this plot standard emf(E°) of the cell was obtained by extrapolation. The relationship of emf(E) and pH at 25℃ under 1 bar was as follows, E=0.034+0.05918 pH. The slopes were decreased with increasing pressure, and emf(E) was increased. These phenomena may be caused to the activities of water, Cl^-, Sb_2, Sb_2O_3, Ag, and AgCl. In plot of pressure and pH the decrease of pH values was due to the increase of dissociation constant of hydrochoric acid. Even though the stick antimony electrode could be useful to 500 bars at 30℃, it could be useful to 1000 bars below 30℃.
電氣的 開始法에 의한 2-Hydroxyethyl methacrylate의 重合과 이들 膜의 電氣的 性質
黃正儀,鄭倧在,車星極 慶北大學校 1978 論文集 Vol.25-26 No.-
The electroinitiated polymerization of 2-hydroxy ethyl methacrylate (HEMA) has been studied at the various voltages, from 2 to 2500 volts. The rate of polymerization was increased with increasing voltages. It was supposed that the orientation and migration effect of monomer accelerating the rate. The membranes were molded between two separated glass plates. These membranes have been used to measure the membrane potentials and the transport number of Na^+ ion and water. The measured membrane potentials and calculated values, which were related by Scatchard theory, gave satisfactory agreement below 0.1m. This was due to permselectivity of HEMA membranes, which had high fixed-OH group in the pore as a pendent. The main deviations of measured membrane potentials (E_c) and the maximum possible values of electrical potentials (E_max) were due to transport numbers of Cl^-ion and water. Therefore it seems to be make an useful strong hemodialysis HEMA membranes by electroinitiated grafting polymerization.
초격자 고경도 나노 다층막 소재의 복합경도 해석을 통한 계면 강화 효과 분석
김성훈,이윤희,박종극,백영준,권동일 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.12
Multilayer coatings consisting of very thin layers of nitride materials deposited by magnetron sputtering (sometimes called superlattices) exhibit hardnesses over 50 GPa, much higher than that of single layers. Several explanations for this hardness increase have been proposed, including dislocation blocking by layer interfaces, Hall- Petch strengthening, strain effects at layer interfaces, and the supermodulus effect. Among these, dislocation blocking has been generally accepted as a dominant factor in large hardness enhancement. However, the interface between two materials consisting of multilayers is broadened due to interdiffusion. The magnitude of hardness enhancement by the interface has not yet been quantified for real systems. In this study, the concept of composite hardness is introduced to quantify the interface-related hardness enhancement. We suggest a composite hardness equation and quantifythe magnitude of hardness increase by using an equation based on the interface hardness and the interface thickness derived by comparing results derived from this equation and those determined in nanoindentation tests. Three multilayer systems, such as TiN/VN, TiN/NbN and CrN/NbN were used in the equation.
INFERENCING THE NUMBER OF CLUSTERS WITH BAYESIAN INFORMATION CRITERION
Jong-Keuk Lee,Gyeongyong Heo,Soowhan Han,Young Woon Woo 한국멀티미디어학회 2007 한국멀티미디어학회 국제학술대회 Vol.2007 No.-
K-means is one of the simplest unsupervised learning algorithms that solve the clustering problem. However K-means suffers the basic shortcoming: the number of clusters k has to be known in advance. In this paper, we propose an extension of X-means, which is parameter-free and can estimate the number of clusters using Bayesian Information Criterion (BIC). X-means, however, suffers severe over-fitting when the data does not follow a spherical Gaussian distribution due to the diagonal covariance matrix assumption. We introduce two different versions of algorithm; Modified X-means (MX-means) and Generalized X-means (GX-means), which employ one full covariance matrix for one cluster and can estimate the number of clusters efficiently without severe over-fitting and any additional parameters. The algorithms start with one cluster and try to split one cluster iteratively to maximize the BIC score. The former uses the traditional K-means algorithm to find a set of optimal clusters with current k, the number of clusters, which makes it faster than the latter. However it generates incorrectly estimated centers when the clusters are overlapped. The latter uses EM algorithm to estimate the parameters instead of K-means and generates more stable clusters even when the clusters are overlapped. Experiment with synthetic data shows that the proposed methods can provide a robust estimate of the number of clusters and cluster parameters compared to other top-down algorithms.