• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.174-174
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• 2010

Gallium Nitride(GaN) attracts great attention due to their wide band gap energy (3.4eV), high thermal stability to the solid state lighting devices like LED, Laser diode, UV photo detector, spintronic devices, solar cells, sensors etc. Recently, researchers are interested in synthesis of polycrystalline and amorphous GaN which has also attracted towards optoelectronic device applications significantly. One of the alternatives to deposit GaN at low temperature is to use Single Source Molecular Percursor (SSP) which provides preformed Ga-N bonding. Moreover, our group succeeds in hybridization of SSP synthesized GaN with Single wall carbon nanotube which could be applicable in field emitting devices, hybrid LEDs and sensors. In this work, the GaN thin films were deposited on c-axis oriented sapphire substrate by MBE (Molecular Beam Epitaxy) using novel single source precursor of dimethyl gallium azido-tert-butylamine($Me_2Ga(N_3)NH_2C(CH_3)_3$) with additional source of ammonia. The surface morphology, structural and optical properties of GaN thin films were analyzed for the deposition in the temperature range of $600^{\circ}C$ to $750^{\circ}C$. Electrical properties of deposited thin films were carried out by four point probe technique and home made Hall effect measurement. The effect of ammonia on the crystallinity, microstructure and optical properties of as-deposited thin films are discussed briefly. The crystalline quality of GaN thin film was improved with substrate temperature as indicated by XRD rocking curve measurement. Photoluminescence measurement shows broad emission around 350nm-650nm which could be related to impurities or defects.

• The Korean Journal of Physiology and Pharmacology
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• v.11 no.5
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• pp.175-182
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• 2007

Members of prostaglandin(PG) E-series elicit cellular effects mainly through adenylyl cyclase-cAMP signaling. The role of $PGE_2$-induced increase in cAMP has been shown to be compartmentalized in the cardiac myocytes: $PGE_2$-induced increase of cAMP is not involved in the control of cardiomyocytic contraction. The purpose of the present study was to define the effect of $PGE_1$ on the cGMP levels and the role of $PGE_1$ in the atrial secretory function. Experiments were performed in perfused beating rabbit atria and atrial contractile responses, cGMP and cAMP efflux, and atrial natriuretic peptide(ANP) secretion were measured. $PGE_1$ increased cGMP as well as cAMP efflux concentration in a concentration-dependent manner, however, no significant changes in atrial secretory responses were observed(with $1.0{\mu}M\;PGE_1$; for cGMP, $144.76{\pm}37.5%$, n=11 versus $-16.81{\pm}4.76%$, n=6, control, p<0.01; for cAMP, $187.60{\pm}41.52%$, n=11 versus $7.38{\pm}19.44%$, n=6, control, p<0.01). $PGE_1$ decreased atrial dynamics slightly but transiently, whereas $PGE_2$ showed similar effects but with lower potency. Isoproterenol increased atrial cAMP efflux(with 2.0 nM; $145.71{\pm}41.89$, n=5 versus $7.38{\pm}19.44%$, n=6, control, p<0.05) and mechanical dynamics and decreased ANP secretion. The $PGE_1$-induced increase in cGMP efflux showed a bell-shaped concentration-response curve. $PGE_1$-induced increase of cGMP efflux was not observed in the presence of L-NAME, an inhibitor of nitric oxide(NO) synthase, or ODQ, an inhibitor of NO-sensitive guanylyl cyclase. L-NAME and ODQ showed no significant effect on the $PGE_1$-induced transient decrease of atrial dynamics. These data indicate that $PGE_1$ increases cGMP levels via NO-soluble GC signaling in the cardiac atrium and also show that $PGE_1$-induced increases in cGMP and cAMP levels are not involved in the regulation of atrial secretory and contractile functions.

• Journal of Microbiology
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• v.40 no.2
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• pp.119-124
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• 2002

Experiments for the characterization of inactivation were performed in a series of batch processes with the total coliform used as a general indicator organism based on the chlorine residuals as a disinfectant. The water samples were taken from the outlet of a settling basin in a conventional surface water treat- ment system that is provided with the raw water drawn from the mid-stream of the Han River, The inactivation of total coliform was experimentally analysed for the dose of disinfectants contact time, filtration and mixing intensity. The curves obtained from a series of batch processes were shaped with a general tailing-off and biphasic mode of inactivation, i.e. a sharp loss of bacterial viability within 15 min followed by an extended phase. In order to observe the effect of carry-over suspended solids on chlorine consumption and disinfection efficiency, the water samples were filtered, prior to inoculation with coliforms, with membranes of both 2.5$\mu$m and 11.0 $\mu$m pore size, and with a sand tilter of 1.0 mm in effective size and of 1.4 in uniformity coefficient. As far as the disinfection efficiency is concerned, there were no significant differences. The parameters estimated by the models of Chick-Wat-son, Hom and Selleck from our experimental data obtained within 120 min are: log(N/N$\_$0/)=-0.16CT with n=1, leg(N/N$\_$0/)=-0.71C$\^$0.87/ with n 1 for the Chick-Watson model, log (N/N$\_$0/)=-1.87C$\^$0.47/ T$\^$0.36/ for the Hom model, log (MHo)=-2.13log (1+CT/0.11) for the Selleck model. It is notable that among the models reviewed with regard to the experimental data obtained, the Selleck model appeared to most closely resemble the total coliform survival curve.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.9
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• pp.73-84
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• 2004

This paper suggests a new scalar multiplication algerian to resist SPA which threatens the security of cryptographic primitive on the hardware recently, and discusses how to apply this algerian Our algorithm is better than other SPA countermeasure algorithms aspect to computational efficiency. Since known SPA countermeasure algorithms have dependency of computation. these are difficult to construct parallel architecture efficiently. To solve this problem our algorithm removes dependency and computes a multiplication and a squaring during inversion with parallel architecture in order to minimize loss of performance. We implement hardware logic with VHDL(VHSIC Hardware Description Language) to verify performance. Synthesis tool is Synplify Pro 7.0 and target chip is Xillinx VirtexE XCV2000EFGl156. Total equivalent gate is 60,508 and maximum frequency is 30Mhz. Our scalar multiplier can be applied to digital signature, encryption and decryption, key exchange, etc. It is applied to a embedded-micom it protects SPA and provides efficient computation.

• Korean Journal of Environmental Agriculture
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• v.30 no.2
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• pp.196-201
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• 2011

BACKGROUND: Bioavailability enhancement by solubilization of lipophilic drugs in nano-emulsion has been reported and it may be useful in pharmaceutical and nutraceutical products. This study was performed to compare in vivo bioavailability of nano-emulsion formulation with that of the general product as control. METHODS AND RESULTS: The pharmacokinetics assessment of Vitamin A, D and E complex of nanoemulsion formulation (LaVita), in comparison to the general product, was performed in the male rat plasma by a single oral dose at 20 mL/kg body weight (n=3/group). For nano-emulsion formulation (LaVita), $C_{max}$ of vitamin A and E in plasma were much higher and the area under the curve (AUC) of vitamin A, D and E were 14-63% higher, and the half-life of vitamin E was 2-fold longer than the general product. According to statistical analysis, each $C_{max}$ of vitamin A, D & E was significantly higher (p<0.01, 0.05 and 0.01, respectively) than that of general product. Half-life of vitamin A was significantly higher (p<0.01) and AUC of vitamin A and D were also significantly higher than the general product. CONCLUSION(s): Considering significant increment of $C_{max}$ and AUC, LaVita made of nano-emulsion could be more effective the absorption rate and extent for bioavailability of vitamin A, D & E than those of general product.

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.2
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• pp.1-12
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• 1989

This paper presents a method of minimizing the wave resistance components, due to the linear wave propagating to the far field and the breaking wave in the vicinity of the hull. This method consists of the linear optimization method for the linear wave resistance and the statistical optimization method for the breaking wave resistance through the analysis of the experimental data. For the purpose of the application, a wall-sided model with parabolic waterplane shape was selected as a basic hull form, and two modified hull forms with varied $C_p-curve$ of the fore-body were derived from the linear wave optimization method and the empirical method. The correlation between the linear wave resistance and the breaking wave resistance according to the $C_p-curve$ variation of the fore-body was investigated through the experimental and analytical results for the three hull forms. The fore-body shape optimized by the present method shows the reduction of the wave resistance by 47% comparing to the basic hull form at the design speed($F_n=0.26$).

• Journal of computational fluids engineering
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• v.20 no.3
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• pp.35-40
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• 2015

Centrifugal pumps consume considerable amounts of energy in various industrial applications. Therefore, improving the efficiency of pumps machine is a crucial challenge in industrial world. This paper presents numerical investigation of flow characteristics in volutes of centrifugal pumps in order to compare the energy consumption. A wide range of volumetric flow rate has been investigated for each case. The standard k-${\varepsilon}$ is adopted as the turbulence model. The impeller rotation is simulated employing the Multi Reference Frames(MRF) method. First, two different conventional design methods, i.e., the constant angular momentum(CAM) and the constant mean velocity (CMV) are studied and compared to a baseline volute model. The CAM volute profile is a logarithmic spiral. The CMV volute profile shape is an Archimedes spiral curve. The modified volute models show lower head value than baseline volute model, but in case of efficiency graph, CAM curve has higher values than others. Finally for this part, CAM curve is selected to be used in the simulation of different cross-section shape. Two different types of cross-section are generated. One is a simple rectangular shape, and the other one is fan shape. In terms of different cross-section shape, simple rectangular geometry generated higher head and efficiency. Overall, simulation results showed that the volute designed using constant angular momentum(CAM) method has higher characteristic performances than one by CMV volute.

• Biomolecules & Therapeutics
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• v.2 no.2
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• pp.114-119
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• 1994

[$^3$H]Ouabain binding parameters ( $K_{D}$ and $B_{max}$) to control rat ventricular strips and Langendorff preparations which were not previously exposed to ouabain were compared with those to both preparations that had been first exposed to a complete ouabain dose range of dose-response curve (10$^{-8}$ to 10$^{4}$M). In rat ventricular strips and Langendorff perfused heart preparations, cumulative dose-response curves of ouabain revealed biphasic positive inotropic effects, a "low-dose" effect and a "high-dose" effect with E $d_{50}$ values of 0.5 $\mu$M and 35 $\mu$M ouabain, respectively. The "low-dose" effect in ventricular strip disappeared or was diminished significantly when the ouabain dose-response curve was repeated after the washout of the effects of the first dose-response curve, whereas there were no significant differences in the maximal "high-dose"effect in both exposures to oubain. However, both of the control and ouabain-preexposed Langendorff perfused hearts revealed the same low-dose effects. The $K_{D}$ value for [$^3$H] ouabain binding and the ouabain binding site concentration ( $B_{max}$) estimated by [$^3$H]ouabain displacement assay in control preparations were 230 nM and 2 pmol/mg protein, respectively. [$^3$H]Ouabain binding parameters were not changed by repeated exposure to high concentrations of ouabain. These results suggest that digitalis receptor desensitization in the rat ventricular strip may due to the change of post-receptor events induced by ouabain binding to a high affinity site ($\alpha$$_2$isoform).).).).).

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.460-463
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• 2005

Gear is an important machine element to be used transmission in case short between axis. We drew gear using automatic design program to solve problem when it draw gear. We manufactured gears that it have different pressure angles using W-EDM. And we got a 2D profile of manufactured gear using reverse engineering. So we got to manufacturing error in comparison with CAD data and measured data. In result we could manufacture precise gear through improvement of manufacturing processes.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.842-847
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• 2005

Although there are many applications of Euclidean Voronoi diagram for spheres in a 3D space in various disciplines from sciences and engineering, it has not been studied as much as it deserves. In this paper, we present an edge-tracing algorithm to compute the Euclidean Voronoi diagram of 3-dimensional spheres in O(mn) in the worst-case, where m is the number of edges of Voronoi diagram and n is the number of spheres. After building blocks for the algorithm, we show an example of Voronoi diagram for atoms using actual protein data and discuss its applications for protein analysis.