• Journal of Sensor Science and Technology
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• v.23 no.1
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• pp.51-57
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• 2014

The evaporating materials for $MgGa_2Se_4$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $MgGa_2Se_4$ compounded polycrystal powder was deposited on thoroughly etched semi-insulated GaAs(100) substrate by the hot wall epitaxy (HWE) method system. The source and substrate temperatures of optimized growth conditions, were $610^{\circ}C$ and $400^{\circ}C$, respectively.The source and substrate temperatures were $610^{\circ}C$ and $400^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by double crystal X-ray diffraction (DCXD). The temperature dependence of the energy band gap of the $MgGa_2Se_4$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=2.34\;eV-(8.81{\times}10^{-4}\;eV/K)T^2/(T+251\;K)$. After the as-grown $MgGa_2Se_4$ single crystal thin films was annealed in Mg-, Se-, and Ga-atmospheres, the origin of point defects of $MgGa_2Se_4$ single crystal thin films has been investigated by the photoluminescence (PL) at 10 K. The native defects of $V_{Mg}$, $V_{Se}$ obtained by PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the Se-atmosphere converted $MgGa_2Se_4$ single crystal thin films to an optical n-type. Also, we confirmed that Ga in $MgGa_2Se_4$/GaAs did not form the native defects because Ga in $MgGa_2Se_4$ single crystal thin films existed in the form of stable bonds.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.2
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• pp.117-126
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• 2005

A stoichiometric mixture of evaporating materials for $AgGaS_2$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $AgGaS_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $590^{\circ}C\;and\;440^{\circ}C$, respectively The temperature dependence of the energy band gap of the $AgGaS_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)=2.7284 eV-(8.695{\times}10^{-4}eV/K)T^2/T(T+332K)$. After the as-grown $AgGaS_2$, single crystal thin films was annealed in Ag-, S-, and Ga-atmospheres, the origin of point defects of $AgGaS_2$ single crystal thin films has been investigated by the photoluminescence(PL) at 10K. The native defects of $V_{Ag},\;V_s,\;Ag_{int},\;and\;S_{int}$, obtained by PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the Ag-atmosphere converted $AgGaS_2$ single crystal thin films to an optical n-type. Also, we confirmed that Ga in $AgGaS_2$ crystal thin films did not form the native defects because Ga in $AgGaS_2$ single crystal thin films existed in the form of stable bonds.

• Food Science of Animal Resources
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• v.31 no.6
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• pp.952-959
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• 2011

A new bacteriocin-producing lactic acid bacteria (LAB) which has been isolated from kimchi was identified as Pediococcus damnosus by use of API kit and 16S rDNA sequencing, and designated as P. damnosus JNU 534. The bacteriocin produced by P. damnosus JNU 534 markedly inhibited the growth of some of LAB and Listeria monocytogenes, whereas other pathogens including Gram negative bacteria were not susceptible. The production of bacteriocin started at the beginning of exponential phase and reached maximum activity at the early stationary phase. The bacteriocin was stable on the wide pH range of 2-9 and heat treatment up to $100^{\circ}C$ for 15 min. The antimicrobial compound was inactivated by treatments of proteolytic enzymes indicating its proteinaceous in nature. The bacteriocin was purified by 30% ammonium sulfate precipitation followed by hydrophobic interaction column and $C_{18}$ column chromatography. The estimated molecular weight of the bacteriocin using tricine SDS-PAGE was approximately 3.4 kDa and the identified N-terminal amino acid sequence was $NH_2$-ILLEELNV.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.11
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• pp.1599-1607
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• 2004

This study examined the effects of pre-slaughter fasting, chasing stress and chiller ageing on objective meat quality, and their relations to the proteome profile of longissimus muscle using 20 male Korean native black pigs. Treatments were composed of two levels of pre-slaughter feed withdrawal, two levels of pre-slaughter stress and four chiller ageing times. A 15 min chasing stress immediately prior to slaughter significantly (p<0.05) decreased detectable levels of $\mu$-calpain activity during rigor development and chiller ageing, but did not have any direct effect on objective meat quality. On the other hand, pigs fed until the morning of slaughter resulted in significantly (p<0.05) higher hunter L* value and cooking loss than those which received an 18 h feed withdrawal prior to slaughter. Cooking loss and hunter L* value were constant during 7 d of chiller ageing, followed by significant increases at 14 d. The fed animals showed a significantly (p<0.05) higher hunter a* value at both 3 and 7 d, while the other group maintained a stable redness for 7 d. WB-shear force was not affected by the pre-slaughter treatments, but had significant (p<0.05) linear reduction from 1 to 7 d. A gelbased proteome analysis was performed on selected animals for low and high hunter L* values at 1 d. Ten and five spots had greater than two-fold spot densities for the low and high hunter L* groups, respectively. The ten spots included chain A, deoxyribounclease I complex with actin, heat shock protein 27 kDa, a protein similar to cardiac $Ca^{2+}$ release channel, and myosin heavy chain, while the five spots included chain A aldehyde dehydrogenase, glycerol-3 phosphate dehydrogenase, and hemoglobin alpha chain. In general, feeding until the morning of slaughter resulted in more desirable meat color, but appeared to reduce palatability due to increased cooking loss. Proteome analysis demonstrated that various proteins were concomitantly involved in the determination of final meat color. The most noticeable observation in the current study was that various isoforms for a particular protein differed in degradation and/or expression rate depending on meat quality.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.6
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• pp.688-697
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• 2014

In this study, electrode bonding technology needed for high density of rechargeable battery is studied, which is recently researched for electric vehicle, the small leisure vessel. For the alternative overcoming the limit of stacking amount able to be stacked by conventional ultrasonic welding, the low temperature bonding method, eligible for minimum of degeneration of chemical activator on the electrode surface which is generated by thermal effect as well as the increase of conductivity and tension strength caused by electrode bonding using filler metal, not using conventional direct heating on the electrode material method, is studied. Specifically to say, recently used more generally the ultrasonic welding and spot welding method are not usable for satisfying stable electric conductivity and bonding strength when much electrode is stacking bonded. If the electrical power is unreasonably increased for the welding, due to the effect of welding temperature, deformation of electrode and activating material degeneration are caused, and after the last packaging, decline of electrical output and generating heat cause to reduce stability of battery. Therefore, in this study, induction heating system bonding method using high frequency heating and differentiated electrode method using filler metal pre-treatment of hot dipping are introduced.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.298-308
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• 1994

The properties of polygalacturonase by Ganoderma lucidum in liquid culture were investigated. The enzyme was composed of an endo- and an exo-polygalacturonase. The endo- and exo-polygalacturonase were purified approximately 56 and 9.2-fold, respectively, through ammonium sulfate fractionation, gel filtration on Biogel P-100, anion exchange chromatography on DEAE-cellulose, gel chromatography on Sephadex G-150 and re-gel chromatography on Sephadex G-150. The endo- and exo-polygalacturonase had higher affinity for apple pectin than for citrus pectin or pectic acid. The Km values of the endo- and exo-polygalacturonase for apple pectin, determined on the Lineweaver-Burk plot, were 1.44 and 10.6 mg $ml^{-1}$ for apple pectin, respectively. Purified endo-polygalacturonase was found to be homogeneous electrophoretically and had a molecular weight of 54,000 estimated on SDS polyacrylamide gel. The optimal pH for the activity of the enzymes was 4.0. The endo- and exo-polygalacturonase were stable in the pH range of 4.0 to 6.0 and 3.5 to 5.5, respectively. The optimal temperatures of the endo- and exo-polygalacturonase were 40 and $60^{\circ}C$, respectively. The exo-polygalacturonase was more resistant to heat than the endo-polygalacturonase, requiring heating for 40 min at $80^{\circ}C$ for complete inactivation. The activity of the endo-polygalacturonase was increased by $Ca^{++}$ and $Mn^{++}\;ions$, while that of the exo-polygalacturonase was increased by $Ca^{++}\;ion$ only, and was not affected by $Mn^{++}\;ion$.

• Polymer(Korea)
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• v.26 no.2
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• pp.237-244
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• 2002

Mechanical properties, flow characteristics and chemical resistance of polycarbonate (PC)/polybutylene terephthalate (PBT) /impact modifier (IM) blends were investigated over the various composition ranges of PC and PBT. Mechanical properties of the PC/PBT/IM blends for different IMs, butadiene based IM and butyl acrylate based IM, were studied for various compositions of the IMs. Impact strength at low temperature was also observed. For the study of chemical resistance of the PC/PBT/IM blends, the blonds were dipped in organic solvent, thinner, and then variations of mechanical properties were analyzed. Tensile and flexural strengths were increased linearly and heat distortion temperature (HDT) also increased as PC content in the blends increased. Impact strength increased drastically as PC content increased up to 50 wt% and stayed stable value. Flowability decreased as PC content increased. Impact strengths of the blend were various for different IMs. Butyl acrylate based IM showed slightly higher impact strength than butadiene based IM for the temperature above $0^{\circ}C$. However, butadiene based IM showed remarkably higher impact strength than butyl acrylate based IM for the temperature below $0^{\circ}C$. Through the experiment of chemical resistance it was observed that tensile and flexural strengths decreased, and impact strength increased as PC content in the blends increased. PC in the blend would become mild and ductile when it contacted with organic solvent. Thus the impact strength increased while tensile and flexural strength decreased.

• Korean Journal of Microbiology
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• v.17 no.4
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• pp.165-178
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• 1979

Phages of Lactobaciilus casei (PLC) isolated from plant drainage were classified and characterized. The results are as follows : 1. On the basis of host range pattern, phages could be divided into 2 groups (PLC-B and PLC-C). PLC-B group phages could be further divided into 5 sub-groups $(B_1, \;B_2, \;B_3, \;B_4, \;and\;B_5)$. Although PLC-C group phages had the same host range, they could be also divided into 2 sub-groups $(C_1\;and\;C_2)$ by morphlogical type. 2. It was $B_3$ group phages that represented a major proportion (44.4%) of phages tested. However, $B_1$ group phages were shown to have the widest host range. 3. Electron micrographs revealed that the phages fell into three different morphological types. $(B_1, \;B_2, \;and\;B_3)$ group phages hd a hexagonal head (52nm in diameter) and a sheathless noncontractile (245 nm in length). $B_4\;and\;C_2$ group phages had a hexagonal head (56 nm) and a short flexible tail (169nm) having no sheath. $B_5\;and\;C_1$ group phages were shown to have a hexagonal head (81 nm) and a contractile tail (140 nm) having a sheath, a base plate and tail fibers. 4. The inactivation of the phages by antisera indicated that serological relationships correlated completely with morphological types. 5. $B_1, \;C_1\;and\;C_2$ group phages produced a large (1, 2 mm in diameter) plaque with a clear ring. The morphology of plaques of $B_3\;and\;B_5$ group phages was the same as those produced by the above, but the average plaque sizes for $B_3\;and\;B_5$ were 0.8 mm abd 0.5 mm, respectively. $B_2\;and\;B_4$ group phages produced a small (0.5 mm) turbid plaque with an irregular edge. 6. The latent period and the average burst size of $B_1\;and\;B_3$ group phages were 90 min and 100, respectively. These phages reuqired calcium ions for their miltiplication. 7. $B_3$ group phages could not be absrobed to R-variant $KC_1$. 8. The order of resistance of phages to heat was $B_2\;>\;B_1, B_4\;and\;B_5\;>\;B_3\;and\;C_2, \;B_5$ group phages were more stable than $B_3$ in various pH values. $C_2$ group phages were more sensitive to UV irradiation than $B_1\;and\;B_3$ group phages. 9. Strains YIT9018 and IAM 1043 were induced by mitomycin C treatment. Phage particles detected in the lysates had a hexagonal head (38 and 49 nm, respectively), but no tail. Any sensitive indicator strain could not be isolated in spite of repaeated trials.

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.700-708
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• 2013

Pyroprocessing has been developed for the purpose of resolving the current spent nuclear fuel management issue and enhancing the recycle of valuable resources. Pyroprocessing has been developed with the dry technologies which are performed under high temperature conditions excluding any aqueous processes. Pyro-processes which are based on the electrochemical principles require pretreatment processes and a voloxidation process is considered as a pretreatment step for an electrolytic reduction process. Various kinds of gas conditions are applicable to the voloxidation process and the understanding of Cs behavior during the process is of importance for the analyses of waste characteristics and heat load on the overall pyroprocessing. In this study, the changes of chemical compounds with the gas conditions were calculated by analyzing gas-solid reaction behavior based on the chemical equilibria on a Cs-Te-O system. $Cs_2TeO_3$ and $Cs_2TeO_4$ were selected after a Tpp diagram analysis and it was confirmed that they are relatively stable under oxidizing atmospheres while it was shown that Cs and Te would be removed by volatilization under reducing atmosphere at a high temperature. This work provided basic data for predicting Cs behavior during the voloxidation process at which compounds are chemically distributed as the first stage in the pyroprocessing and it is expected that the results would be used for setting up material balances and related purposes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.6
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• pp.840-845
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• 2012

This research was done to verify the inhibitory activity of water extracts from Ecklonia cava (WE-EC) against trypsin and the effects on various temperature and pH conditions. The WE-EC showed high trypsin inhibitory activity of 76, 62 and 60% at concentrations of 5, 2.5 and 1 mg/mL, respectively. In all heat treatments excepted for two conditions, such as $100^{\circ}C$ for 20 min and $121^{\circ}C$ for 15 min, the inhibitory activity was stable compared with the untreated group. With regard to pH stability, the WE-EC showed no significant changes at pH 2~8, but somewhat decreased inhibitory activity was revealed at pH 10. Therefore, the WE-EC could be used in the food industry as a natural trypsin inhibitor.