• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2007.11a
• /
• pp.126-127
• /
• 2007

Sn-filled and Fe-doped $CoSb_3$ skutterudites were synthesized by encapsulated induction melting. Single ${\delta}$-phase was successfully obtained by subsequent annealing and confirmed by X-ray diffraction analysis. Temperature dependences of Seebeck coefficient, electrical resistivity and thermal conductivity were examined from 300 K to 700 K. The positive Seebeck coefficient confirmed the p-type conduction. Electrical resistivity increased with increasing temperature, which shows that the $Sn_zCo_3FeSb_{12}$ skutterudite is highly degenerate. Thermal conductivity was reduced by Sn-filling because the filler atoms acted as phonon scattering centers in the skutterudite lattice. Thermoelectric figure of merit was enhanced by Sn filling and its optimum filling content was considered to be z=0.3 in the $Sn_zCo_3FeSb_{12}$ system.

• Microbiology and Biotechnology Letters
• /
• v.44 no.3
• /
• pp.317-323
• /
• 2016

An isoflavone glucosidase that catalyzes the hydrolysis of isoflavone glucosides into glucose and corresponding aglycones was purified from Candida fermentati SI. The N-terminal sequence was determined to be GLNCDYCN. We designed degenerate primers on the basis of these amino acid sequences and successfully cloned the full structural gene sequence of the isoflavone glucosidase using inverse PCR. The exo-β-(1,3)-glucanase gene consists of 1227 base-pair nucleotides, encoding a 408-amino-acid sequence that shares 41–96% amino acid homology with other yeast exo-β-(1,3)-glucanases belonging to glycoside hydrolase family 5. The recombinant exo-β-(1,3)-glucanase was expressed in Pichia pastoris X-33, using a pPICZA vector system, and further characterized. The molecular mass of the purified exo-β-(1,3)-glucanase was estimated by SDS-PAGE to be 47 kDa. The optimal pH and temperature were pH 4.5 and 40℃, respectively. The K_m values of the purified exo-β-(1,3)-glucanase for daidzin and genistin were 0.12 mM and 0.14 mM, respectively. The V_max values of the purified isoflavone glucosidase were 945.03 U/mg for daidzin and 835.92 U/mg and for genistin.

• Journal of the Korean Chemical Society
• /
• v.34 no.1
• /
• pp.37-43
• /
• 1990

An effect of the spin-orbit coupling interaction of ligand orbitals and the intermixing │3d 〉and│4p > transition metal atomic orbitals on the ground state for a 3$d^9$ system in a strong crystal field of tetragonally distorted tetrahedral symmetry that belongs to the $D_{2d}$ point group has been investigated in this work, applying the degenerate perturbation theory. An LCAO-MO analysis in terms of the known energies of the d-d transitions for the tetragonally distorted $CuCl_4^{2-}$ ion in a single crystal of$Cs_2CuCl_4$shows that the covalent mixing of Cu 3d and ligand Cl 3p orbitals decreases dramatically with increasing Cu 4p contribution. The extent of effect on the energy level splitting for the ground state by the spin-orbit coupling interaction of ligand orbitals decreases significantly in orderTEX>$\Gamma_7(E)\;\to\;\Gamma_6(E)\; >\;\Gamma_7(B_2)\;\to\;\Gamma_6(E)\; >\;\Gamma_7(B_2)\;\to\;\Gamma_7(E)$.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.3 no.1
• /
• pp.28-30
• /
• 1978

Communication actions as a social band or Human community stick (fast) to human being ceaselessly w without stopping everywhere. All of comm. actions can be kept up and developed by the education of its own. Comm. actions have to include a character of social process, and so for it the social science should t to be some essential part of it. Therefore, Comm. education have to be schemed for achieving with a point of view of synthetical s science including technical and social factor. However, recentry Comm. education be suffered to lose of itowns essential attribute and individual i independence becausing to reduce social weight recklessly in their education It is a prindiple that Comm. science is an integrate science being composed of human, social and t technical subdepartments and so comm. education have to obey for Comm. constuctional theory, i international and social claim. Originally in Korea a educational idea and genealogy forming by the comm. scientific theory has I inherited on orthodoxy. But in 1961, communication college that is only the orthodox model of Comm. education, was f forced to close by some reckless policy and then the national administration for the Comm. education h have been weakened, and so recently it’s education became to degenerate as out of genealogy or n nonsystem alike some scattering Family. On the other side, today comm. science make to it’s modern scientific factor and to keep its l integrate level, therefore, all of educational provisions and administration for the telecomm. should t to be supplement to be fit for their plural chatacters. Comm. education have to occupy an individual educational system through the comm. theory, and t then it can be coexisted with neighbour scientific field equally and can include, connect coordinate o or effect its inference in each subfactor organically. Finally, educational system for telecommunication should to be requested as preeedence that i independent field including pluralism must be formed and sufficient autonomy be guarenteed, and s so Comm. education must be to restored its orthodox genealogy and be recovered individual system a and seIfrestraint field, and then it can be accomplished its own duty for nation and society.

• Journal of Embryo Transfer
• /
• v.17 no.2
• /
• pp.145-151
• /
• 2002

The aim of these experiments was to investigate in vitro nuclear maturation of canine oocyte collected from various stages of estrus cycles, Ovaries were obtained from 1 to 4 year-old mongrel bitch and minced for oocyte collection in phosphate buffered saline with 100 iu penicillin-G $m\ell$／sup -1／, 50 $\mu\textrm{g}$ streptomycin sulphate $m\ell$／sup -1／ and 0.1％ (w／v) polyvinyl alcohol. Cumulus-oocyte-complexes (COCs) were washed in HEPES buffered tissue culture medium (TCM)199 and in vitro matured in TCM-199 culture medium supplemented with sodium pyruvate 0.028mg/$m\ell$, L-glutamine 0.146mg／$m\ell$, penicillin G 10,000 IU／$m\ell$, streptomycin 0.031mg／$m\ell$ and 10％ (v／v) fatal calf serum. COCs were in vitro matured for 48～72 hrs at 39$^{\circ}C$ in humidified 5％ $CO_2$ in air atmosphere. In vitro matured oocytes were remove the cumulus cells using 0.2％ (v／v) hyaluronidase. After denuding, oocyte were placed in acetic acid : methanol : chlorform solusion (3:6 : 1.5 v／v) for 30 sec and acetic acid: ethanol(1:3 v／v) for 48hrs fixation. Nuclear maturation was classified to GV, GVBD, MI, MII and degenerate oocyte under microscopy after 1％ aceto-orcein stain. In vitro maturation rates at 48hrs were not significantly difference among the oocytes collected from different stage of estrus at 15.9％, 16.3％, 23.7％ and 18.2％ for anestrus, proestrus, estrus and diestrus. However, the oocytes maturation(36.6％) of collected from estrus ovaries were significantly different from oocytes derived from proesturs, diestrus and anestrus ovaries(30.8％, 17.5％ and 22.1％; p＜0.05). The overall in vitro maturation rates were significantly higher (p＜0.05) in 72hrs culture than 48hrs culture system. In summary, there was a tendency for higher in vitro maturation rates with the oocyte collected from estrus ovary than other stages of estrus. Also, for nuclear maturation, in vitro culture of oocyte for 72hrs was better than 48hrs culture.