• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.5
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• pp.295-299
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• 2015

In this paper to improve the ionic conduction properties, lanthanum silicate apatite $La_{9.33}(SiO_4)_6O_2$ ceramic, which substituted by V ions at Si-site, were fabricated by the mixed-oxide method. And we investigated the structural and electrical properties of $La_{9.33}(Si_{6-x}V_x)O_{26}$ specimens with variation of dopants for the application of solid oxide fuel cells. The sintering temperature of $La_{9.33}(Si_{6-x}V_x)O_{26}$ specimens decreased from $1,600^{\circ}C$ to $1,400^{\circ}C$. As results of X-ray diffraction patterns, all $La_{9.33}(Si_{6-x}V_x)O_{26}$ specimens showed the formation of a complete solid solution in a apatite polycrystallin structure. But the specimens doped with more than 1.5mol% showed the second phase, $La_2SiO_5$ and $SiO_2$. The specimen dopants with 1.0 mol% showed the maximum ion conductivity. Ion conducting and activation energy of the $La_{9.33}(Si_5V_1)O_26$ specimens were about $7.8{\times}10^{-4}S/cm$ 1.62 eV at $600^{\circ}C$, respectively.

• Journal of Yeungnam Medical Science
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• v.6 no.1
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• pp.151-163
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• 1989

Nerve conduction studies help delineate the extent and distribution of the neural lesion. The nerve conduction was studied on upper(median, ulnar and radial nerves) and lower(personal, posterior tibial and sural nerves) extremities in 83 healthy subjects 23 to 66 years of age. and normal values were established(Table 1). The mean motor terminal latency (TL) were : median. 3.6(${\pm}0.6$)milliseconds ; ulnar. 2.9(${\pm}0.5$) milliseconds ; radial nerve. 2.3(${\pm}0.4$) milliseconds. Mean motor nerve conduction velocity(MNCV) along distal and proximal segments: median. 61.2(${\pm}9.1$) (W-E) and 57.8(${\pm}13.2$) (E-Ax) meters per second ; ulnar. 63.7(${\pm}9.1$) (W-E) and 50.(${\pm}10.0$) meters per second. Mean sensory nerve conduction velocity(SNCV) : median. 34.7(${\pm}6.7$) (F-W), 63.7(${\pm}7.1$) (W-E) and 62.8(${\pm}12.3$) (E-Ax)meters per second ; ulnar. 38.0(${\pm}6.7$)(F-W), 63.4(${\pm}7.5$) (W-E) and 57.0(${\pm}10.1$) (E-Ax)meters per second ; radial, 45.3(${\pm}6.8$) (F-W) and 64.2(${\pm}11.0$) (W-E) meters per second ; sural nerve, 43.4(${\pm}6.1$) meters per second. The amplitudes of action potential and H-reflex were also standardized. Mean H latency was 28.4(${\pm}3.2$) milliseconds. And. the fundamental principles, several factors altering the rate of nerve conduction and clinical application of nerve stimulation techniques were reviewed.

• Korean Journal of Materials Research
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• v.12 no.6
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• pp.464-469
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• 2002

$SrBi_2Nb_2O_9(SBN)$ thin films were grown on Pt/Ti/Si and p-type Si(100) substrates by rf-magnetron co-sputtering method using two ceramic targets, $SrNb_2O_6\; and \;Bi_2O_3$. The structural and electrical characteristics have been investigated to confirm the possibility of the SBN thin films for the applications to destructive and nondestructive read out ferroelectric random access memory(FRAM). For the optimum growth condition X-ray diffraction patterns showed that SBN films had well crystallized Bi-layered perovskite structure after $700^{\circ}C$ heat-treatment in furnace. From this specimen we got remnant polarization $(2P_r)$ of about 6 uC/$\textrm{cm}^2$ and coercive voltage $(V_c)$ of about 1.5 V at an applied voltage of 5 V. The leakage current density was $7.6{\times}10^{-7}$/A/$\textrm{cm}^2$ at an applied voltage of 5V. And for the NDRO-FRAM application, properties of SBN films on Si substrate has been investigated. From transmission electron microscopy (TEM) analysis, we found the furnace treated sample had a native oxide about 2 times thicker than the RTA treated sample and this thick native oxide layer had a bad effect on C-V characteristics of SBN/Si thin film. After $650^{\circ}C$ RTA process, we got the improved memory window of 1.3 V at an applied voltage of 5 V.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.12
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• pp.1743-1748
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• 2003

The effect of pH on the fermentation characteristics and the formation of cis-9, trans-11 conjugated linoleic acid (CLA) and trans-11 octadecenoic acid by mixed ruminal bacteria was examined in vitro when incubated with linseed or rapeseed. Concentrate (1%, w/v) with ground linseed (0.6%, w/v) or rapeseed (0.5%, w/v) was added to 600 ml mixed solution of strained rumen fluid with artificial saliva (1:1, v/v), and was incubated anaerobically for 12 h at $39^{\circ}C$. The pH of culture solution was maintained at level close to 4.5, 5.3, 6.1 and 6.9 with 30% $H_2SO_4$ or 30% NaOH solution. pH increment resulted in increases of ammonia and total volatile fatty acid (VFA) concentration in culture solutions containing both oilseeds. Fermentation did not proceeded at pH 4.5. Molar proportion of acetate decreased but that of propionate increased as pH increased when incubated with oilseeds. While the hydrogenating process was very slow at the pH range of 4.5 to 5.3, rapid hydrogenation was found from the culture solutions of pH 6.1 and 6.9 when incubated with linseed or rapeseed. As pH in culture solution of linseed or rapeseed increases proportions of oleic acid (cis-9 $C_{18:1}$) and trans-11 octadecenoic acid increased but those of linoleic acid and linolenic acid decreased. The CLA proportion increased with pH in culture solution containing rapeseed but CLA was mostly not detected from the incubation of linseed.

• Journal of Technologic Dentistry
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• v.30 no.1
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• pp.25-31
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• 2008

Cp-Ti and Ti-6Al-4V alloys commonly used dental implant materials, particularly for orthopaedic and osteosynthesis because of its suitable mechanical properties and excellent biocompatibility. This alloys have excellent corrosion behavior in the clinical environment. The first factor to decide the success of dental implantation is sufficient osseointegration and high corrosion resistance between on implant fixture and its surrounding bone tissue. In this study, in order to increase corrosion resistance and biocompatibility of Cp-Ti and Ti-6Al-4V alloy that surface of manufactured alloy was coated with TiN by RF-magnetron sputtering method. The electrochemical behavior of TiN coated Cp-Ti and Ti-6Al-4V alloy were investigated using potentiodynamic (EG&G Co, PARSTAT 2273. USA) and potentiostatic test (250mV) in 0.9% NaCl solution at 36.5 $\pm$ 1$^{\circ}C$. These results are as follows : 1. From the microstructure analysis, Cp-Ti showed the acicular structure of $\alpha$-phase and Ti-6Al-4V showed the micro-acicular structure of ${\alpha}+{\beta}$ phase. 2. From the potentiodynamic test, Ecorr value of Cp-Ti and Ti-6Al-4V alloys showed -702.48mV and -319.87mV, respectively. Ti-6Al-4V alloy value was higher than Cp-Ti alloy. 3. From the analysis of TiN and coated layer, TIN coated surface showed columnar structure with 800 nm thickness. 4. The corrosion resistance of TiN coated Cp-Ti and Ti-6Al-4V alloys were higher than those of the non-coated Ti alloys in 0.9% NaCl solution from potentiodynamic test, indicating better protective effect. 5. The passivation current density of TiN coated Cp-Ti and Ti-6Al-4V alloys were smaller than that of the noncoated implant fixture in 0.9% NaCl solution, indicating the good protective effect resulting from more compact and homogeneous layer formation.

• Bulletin of the Korean Chemical Society
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• v.21 no.9
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• pp.913-918
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• 2000

Vanadium oxide catalyst supported on TiO2-ZrO2 has been prepared by adding Ti(OH)4-Zr(OH)4 powder to an aqueous solution of ammonium metavanadate followed by drying and calcining at high temperatures. The char-acterization ofthe prepared catalysts was performed using solid-state 51V NMR and FTIR.In thecase ofcalci-nation temperature at 773 K, vanadium oxide was in a highly dispersed state for the samples containing low loading V2O5 below 25 wt %, but for samplescontaining high loading V2O5 equal to or above 25 wt %, vana-dium oxidewas well crystallized due to the V2O5 loading exceeding the formation of monolayer on the surface of TiO2-ZrO2.The ZrV2O7 compound was formed through the reactionof V2O5 and ZrO2 at 773-973 K, where-as the V3Ti6O17 compound was formedthrough the reaction of V2O5 and TiO2 at 973-1073 K. The V3Ti6O17 compound decomposed to V2O5 and TiO2 at 1173 K, which were confirmed by FTIR and 51V NMR.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.449-455
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• 1993

Vibrio vulnificus is a recentry recognized halophilic organism that may cause human infections. Patients infected with Vibrio vulnificus often have a history of exposure to the sea, suggesting that the organism may be common inhabitant of marine environment. In this studies 314 samples were collected from 9 sites of Chonnam coastal area, from April to Jun, 1993. Isolation rates of V. vulnificus were 7.1% in total samples, 33.3% in sea water, 55.5% in sediment, 1.7% in fish and shellfish, 6.3% in kitchen environment. In each areas of Chunnam V. vunificus were isolated from 3.6% to 11.4%. The isolation rates of V. vulnificus was correlated positively with organic matter and COD in sea warer and sediment. In sea water, Microorganism population were $4.5{\times}10^3{\sim}3.5{\times}10^5\;CFU/ml$, Vibrio strains were $1.8{\times}10^l4.6{\times}10^3\;CFU/ml$, Coliform bacteria were $1.9{\times}10^1{\times}3.7{\times}10^2\;CFU/100ml$. In sediment, Microorganism population were $4.8{\times}10^3{\sim}5.2{\times}10^5\;CFU/ml$. Vibrio strains were $1.9{\times}10^2{\sim}8.4{\times}10^4\;CFU/ml$, Coliform bacteria were $7.2{\times}10^1{\sim}9.9{\times}10^2\;CFU/100ml$.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1053-1058
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• 2021

This paper presents the multi-band mixer which converts a X-, K- and Ka-band adaptively by adjusting the gate-bias voltage of an active device. The proposed mixer presented a conversion loss of -10 dB at -0.8 V gate-bias voltage for X-band, a conversion loss of -9 dB at -0.3 V gate-bias voltage for K-band and for Ka-band, a conversion loss of -7 dB at -0.2 V gate-bias voltage under the LO power of +6.0 dBm. The 1dB compression point (P1dB) is +0.5 dBm for all band.

• Journal of Microbiology and Biotechnology
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• v.4 no.4
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• pp.316-321
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• 1994

We investigated the possibility of industrial application and economit process of high temperature fermentation by thermotolerant alcohol producing yeasts as previously reported. From the 20% glucose media, the RA-74-2 produced 11.8% (v/v) ethanol at $32^{\circ}C$ (0.5% inoculum) and 10.6% (v/v) ethanol at $40^{\circ}C$ (3% inoculum), respectively. Also, 11.3% (v/v) ethanol was produced for 96 hours in the temperature-gradient fermentation. These results suggest that the RA-74-2 could isuccessfully be applied to save the cooling water and energy in industrial scale without re-investment or modification of established fermentation systems. When potato starch was used as the substrate for the RA-74-2, high temperature fermentation above $40^{\circ}C$ was more appropriate for industrial utilization because organic nitrogen was not necessary to economical fermentation. As the naked barley media just prior to industrial inoculation, taken from the Poongkuk alcohol industry Co., were used, 9.6% (v/v) ethanol was produced at $40^{\circ}C$ for 48 hours in jar-fermentor scale (actually, 9.5-9.8% (v/v) ethanol was produced at 30~$32^{\circ}C$ for 100 hours in industrial scale). The ethanol productivity was increased by the high glucoamylase activity as well as the high metabolic ratio at $40^{\circ}C$ Therefore, if the thermotolerant yeast RA-74-2 would be used in industrial scale, we could obtain a high productivity and saving of the cooling water and energy. Meanwhile, the RA-912 produced 6%(v/v) ethanol in 10% glucose media at $45^{\circ}C$ and showed the less ethanol-tolerance compared with industrial strains. As the produced alcohol was recovered by the vacuum evaporator at $45^{\circ}C$ in 15% glucose media, the final fermentation ratio was enhanced (76% of theoretical yields). This suggest that a hyperproductive process could be achieved by a continuous input of the substrate and continuous recovery of the product under vacuum in high cell-density culture.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.239-240
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• 2008

The $V_{1.9}W_{0.1}O_5$ thin films deposited on Pt/Ti/$SiO_2$/Si substrates by RF sputtering method exhibited fairly good TCR and dielectric properties. It was found that film crystallinity, dielectric properties, and TCR properties were strongly dependent upon the annealing temperature. The dielectric constants of the $V_{1.9}W_{0.1}O_5$ thin films annealed at $400^{\circ}C$ were 39.6, with a dielectric loss of 0.255, respectively. Also, the TCR values of the $V_{1.9}W_{0.1}O_5$ thin films annealed at $400^{\circ}C$ were about -3.15%/K.