• Journal of Fisheries and Marine Sciences Education
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• v.28 no.5
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• pp.1417-1434
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• 2016

Starting from the February 2008 till the end of November 2014, abundance of phytoplankton and their composition living in the coastal waters of Kyoungju city were investigated. Environmental and biological properties were also observed at 10 different stations on a seasonal basis. Due to the environmental variables, fluctuating pattern was appeared during the entire period of observation with different degree, as compared to those found in other costal waters in the East Sea. The concentration of phosphate was turned out to be very low which was even less than threshold level in the study area. Phytoplankton community structure was dominated by diatoms (both micro- and nanoplankton fractions) for several years and seasonal succession was also relied on the diatoms. The importance of dinoflagellates in the community was relatively low. Abundance of phytoplankton was heavily affected by physical factors in the surface water, however, affected more by chemical factors including nutrients in the deep water. For periods of this study, the phosphate concentrations was observed in an extremely low, which indicates that the main limiting factor affecting phytoplankton growth could be phosphate.

• Proceedings of the Ginseng society Conference
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• 1978.09a
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• pp.85-92
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• 1978

The aim of the double blind test was to assess the prophylactic and therapeutic efficacy of the preparation GINSANA, containing the standardized ginseng extract PHARMATON G115,. The determination was carried out with special emphasis on the following features : general physical condition, physical performance, mental performance, enjoyment of life/mood, concentration and memory, as well as sleeping habits. Sixty test persons took part in the study, men and women between the ages of 22 and 80. The 90-day test was carried out in the form of a double blind experiment. Experimental measurements were made and the persons were also questioned. The reaction time, the optical merging threshold, the coordination of both hands and the recovery quotients, as well as the recovery rates were analyzed. The results for the serum group were clearly better than those for the placebo group, particularly for the characteristics: general physical condition, physical performance and sleeping habits. The results of the test methods used, especially with regard to the reaction time, the coordination of both hands, the recovery quotient and the recovery period, permit the following conclusion to be drawn: when administered for several weeks, GINSANA has a positive action, in the sense of an activation of the entire personality by the ginseng glycosides contained in the standardized Extracts G115.

• ETRI Journal
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• v.26 no.1
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• pp.7-13
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• 2004

To improve the characteristics of breakdown voltage and specific on-resistance, we propose a new structure for a LDMOSFET for a PDP scan driver IC based on silicon-on-insulator with a trench under the gate in the drift region. The trench reduces the electric field at the silicon surface under the gate edge in the drift region when the concentration of the drift region is high, and thereby increases the breakdown voltage and reduces the specific on-resistance. The breakdown voltage and the specific on-resistance of the fabricated device is 352 V and $18.8 m{\Omega}{\cdot}cm^2$ with a threshold voltage of 1.0 V. The breakdown voltage of the device in the on-state is over 200 V and the saturation current at $V_{gs}=5V$ and $V_{ds}$=20V is 16 mA with a gate width of $150{\mu}m$.

• Macromolecular Research
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• v.12 no.1
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• pp.53-62
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• 2004

We have prepared polymer composites of low-density polyethylene (LDPE) and ionomers (Surlyn 8940) containing polar segments and metal ions by melt blending with carbon black (CB) as a conductive filler. The resistivity and positive temperature coefficient (PTC) of the ionomer/LDPE/CB composites were investigated with respect to the CB content. The ionomer content has an effect on the resistivity and percolation threshold of the polymer composites; the percolation curve exhibits a plateau at low CB content. The PTC intensity of the crosslinked ionomer/LDPE/CB composite decreased slightly at low ionomer content, and increased significantly above a critical concentration of the ionomer. Irradiation-induced crosslinking could increase the PTC intensity and decrease the NTC effect of the polymer composites. The minimum switching current (Ι$\sub$trip/) of the polymer composites decreased with temperature; the ratio of Ι$\sub$trip/ for the ionomer/LDPE/CB composite decreased to a greater extent than that of the LDPE/CB composite. The average temperature coefficient of resistance (${\alpha}$$\sub$T/) for the polymer composites increased in the low-temperature region.

• Korean Journal of Optics and Photonics
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• v.6 no.3
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• pp.228-232
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• 1995

We have made modulation doped SMQW-PBH-DFB-LD for high speed optical communications. The waveguide and barrier layers were doped by Zn with the concentration of $1.2 \times 10^{18}cm^{-1}$. Mean threshold current and slope efficiency were 24.88 mA (minimum 16 mA) and 0.197 mW/mA (maximum 0.275 mW/mA) respectively. Linewidth enhancement factor ($\alpha$) of MD-SMQW-PBH-DFB-LD was reduced than that of SMQW-PBH-DFB-LD. Linewidth enhancement factor of 1.8 owes to the large gain coefficient of modulation doped active layer. The resonance frequency was linearly increased with the square root of optical power. The resonance frequency in small signal modulation was measured as 8 GHz and -3 dB modulation bandwidth was 10 GHzat $46mA(I_{th}+30mA)$..

• Journal of the Korea Concrete Institute
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• v.17 no.2 s.86
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• pp.303-309
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• 2005

This study aims the evaluation of the corrosion of steel bar embedded in antiwashout underwater concrete, which has rather been neglected to date. To that goal, accelerated steel bar corrosion tests have been performed on three series of steel bar-reinforced antiwashout underwater concrete specimens manufactured with different admixtures. The three series of antiwashout underwater concrete were: concrete constituted exclusively with ordinary portland cement (OPC), concrete composed of ordinary portland cement mixed with fly-ash in $20\%$ ratio (FA20), and concrete with ground granulated blast furnace slag mixed in $50\%$ ratio (BFS50). The environment of manufacture was in artificial seawater. Measurement results using half-cell potential surveyor showed that, among all the specimens, steel bar in OPC was the first one that exceeded the threshold value proposed by ASTM C 876 with a potential value below -350mv after 14 cycles. And, the corresponding corrosion current density and concentration of water soluble chloride were measured as $30{\mu}A/mm^2$ and $0.258\%$. On the other hand, for the other specimens that are FA20 and BFS50, potential values below -350mV were observed later at 18 and 20 cycles, respectively. Results confirmed the hypothesis that mineral admixtures may be more effective on delay the development of steel bar corrosion in antiwashout underwater concrete.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.5
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• pp.241-246
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• 2002

We studied the excitatory action of morphine on the responses of dorsal horn neuron to iontophoretic application of excitatory amino acid and C-fiber stimulation by using the in vivo electrophysiological technique in the rat. In 137 of the 232 wide dynamic range (WDR) neurons tested, iontophoretic application of morphine enhanced the WDR neuron responses to N-methyl-D-aspartate (NMDA), kainate, and graded electrical stimulation of C-fibers. Morphine did not have any excitatory effects on the responses of low threshold cells. Morphine-induced excitatory effect at low ejection current was naloxone-reversible and reversed to an inhibitory action at high ejection current. NMDA receptor, calcium channel and intracellular $Ca^{2+}$ antagonists strongly antagonized the morphine-induced excitatory effect. These results suggest that changes in intracellular ionic concentration, especially $Ca^{2+},$ play an important role in the induction of excitatory effect of morphine in the rat dorsal horn neurons.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.1
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• pp.9-14
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• 2000

$K^+$ currents play multiple roles in the excitability of dorsal root ganglion (DRG) neurons. Influences on these currents change the shape of the action potential, its firing threshold and the resting membrane potential. In this study, whole cell configuration of patch clamp technique had been applied to record the blocking effect of capsaicin, a lipophilic alkaloid, on the delayed rectifier $K^+$ current in cultured small diameter DRG neurons of adult rat. Capsaicin reduced the amplitude of $K^+$ current in dose dependent manner, and the concentration-dependence curve was well described by the Hill equation with $K_D$ value of $19.1{\mu}M.$ The blocking effect of capsaicin was reversible. Capsaicin $(10 {\mu}M)$ shifted the steady-state inactivation curve in the hyperpolarizing direction by about 15 mV and increased the rate of inactivation. The voltage dependence of activation was not affected by capsaicin. These multiple effects of capsaicin may suggest that capsaicin bind to the region of $K^+$ channel, participating in inactivation process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.348-349
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• 2007

This paper describes the electrical characteristics of polycrystalline (poly) 3C-SiC thin film diodes, in which poly 3C-SiC thin films on n-type and p-type Si wafers, respectively, were deposited by APCVD using HMDS, Hz, and Ar gas at $1180^{\circ}C$ for 3 hr. The schottky diode with Au/poly 3C-SiC/Si(n-type) structure was fabricated. Its threshold voltage ($V_d$), breakdown voltage, thickness of depletion layer, and doping concentration ($N_D$) values were measured as 0.84 V, over 140 V, 61nm, and $2.7\;{\times}\;10^{19}\;cm^3$, respectively. The p-n junction diodes fabricated on the poly 3C-SiC/Si(p-type) were obtained like characteristics of single 3C-SiC p-n junction diodes. Therefore, poly 3C-SiC thin film diodes will be suitable microsensors in conjunction with Si fabrication technology.

• Korean Journal of Metals and Materials
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• v.47 no.1
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• pp.38-43
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• 2009

To investigate the effect of RF power on the structural, optical and electrical properties of amorphous InGaZnO (a-IGZO), its thin films and TFTs were prepared by RF magnetron sputtering method with different RF power conditions of 40, 80 and 120 W at room temperature. In this study, as RF power during the deposition process increases, the RMS roughness of a-IGZO films increased from 0.26 nm to 1.09 nm, while the optical band-gap decreased from 3.28 eV to 3.04 eV. In the case of the electrical characteristics of a-IGZO TFTs, the saturation mobility increased from $7.3cm^2/Vs$ to $17.0cm^2/Vs$, but the threshold voltage decreased from 5.9 V to 3.9 V with increasing RF power. It is regarded that the increment of RF power increases the carrier concentration of the a-IGZO semiconductor layer due to the higher generation of oxygen vacancies.