• Transactions on Electrical and Electronic Materials
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• v.8 no.6
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• pp.241-245
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• 2007

[ $(Ba_{0.9-x}Sr_xCa_{0.10})TiO_3$ ] (x=0.33, 0.36) powders were prepared by sol-gel method. $(Ba,Sr,Ca)TiO_3$(BSCT) thick films, undoped and doped with $MnCO_3$ and $Yb_2O_3(0.1{\sim}0.7mol%)$, were fabricated by the screen printing method on the alumina substrate. The coating and drying procedure was repeated 6-times. The Pt bottom electrode was screen printing method on the alumina substrate. These BSCT thick films were annealed at $1420^{\circ}C$ for 2 hr in atmosphere. The upper electrodes were fabricated by screen printing the Ag paste and then firing at $590^{\circ}C$ for 10 min. And then the structured and dielectric properties as a function of the doping amount of $Yb_2O_3$ were studied. As a result of the TG-DTA, exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All BSCT thick films showed XRD patterns of typical cubic peroveskite structure. The average thickness of BSCT thick films was about $70^{\mu}m$. The curie temperature and the dielectric constant decreased with increasing $Yb_2O_3$ doped content and the relative dielectric constant of the specimen, doped with 0.5 mol% $Yb_2O_3$ at BSCT(54/36/10), showed a best value of 5018 at curie temperature.

• Journal of the Korean Magnetics Society
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• v.25 no.6
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• pp.185-188
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• 2015

We have investigated nuclear magnetic resonance of $^{23}Na$ nucleus in $NaMgCl_3$ single crystal in the temperature range 200 K~410 K using FT-NMR spectrometer. The spin-lattice relaxation times $T_1$ of $^{23}Na$ nucleus residing at cubic symmetry in the host crystal was measured as a function of temperature. The $T_1$ of $^{23}Na$ nucleus decreased with increasing temperature. The nuclear spin-lattice relaxation rate $1/T_1$ of $^{23}Na$ in $NaMgCl_3$ single crystal was proportional to the temperature T. This behavior is explained with the characteristic feature of the direct process between the nuclear spins and single phonon, $1/T_1$ being proportional to the absolute temperature. The activation energy calculated was $E_a=4.82J/mol$.

• Korean Journal of Materials Research
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• v.27 no.1
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• pp.48-52
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• 2017

In this study, we used I-V spectroscopy, photoconductivity (PC) yield and internal photoemission (IPE) yield using IPE spectroscopy to characterize the Schottky barrier heights (SBH) at insulator-semiconductor interfaces of Pt/$HfO_2$/p-type Si metal-insulator-semiconductor (MIS) capacitors. The leakage current characteristics of the MIS capacitor were analyzed according to the J-V and C-V curves. The leakage current behavior of the capacitors, which depends on the applied electric field, can be described using the Poole-Frenkel (P-F) emission, trap assisted tunneling (TAT), and direct tunneling (DT) models. The leakage current transport mechanism is controlled by the trap level energy depth of $HfO_2$. In order to further study the SBH and the electronic tunneling mechanism, the internal photoemission (IPE) yield was measured and analyzed. We obtained the SBH values of the Pt/$HfO_2$/p-type Si for use in Fowler plots in the square and cubic root IPE yield spectra curves. At the Pt/$HfO_2$/p-type Si interface, the SBH difference, which depends on the electrical potential, is related to (1) the work function (WF) difference and between the Pt and p-type Si and (2) the sub-gap defect state features (density and energy) in the given dielectric.

• Molecules and Cells
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• v.39 no.3
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• pp.195-203
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• 2016

Copper is an essential element required for a variety of functions exerted by cuproproteins. An alteration of the copper level is associated with multiple pathological conditions including chronic ischemia, atherosclerosis and cancers. Therefore, copper homeostasis, maintained by a combination of two copper ions ($Cu^+$ and $Cu^{2+}$), is critical for health. However, less is known about which of the two copper ions is more toxic or functional in endothelial cells. Cubic-shaped $Cu_2O$ and CuO crystals were prepared to test the role of the two different ions, $Cu^+$ and $Cu^{2+}$, respectively. The $Cu_2O$ crystal was found to have an effect on cell death in endothelial cells whereas CuO had no effect. The $Cu_2O$ crystals appeared to induce p62 degradation, LC3 processing and an elevation of LC3 puncta, important processes for autophagy, but had no effect on apoptosis and necrosis. $Cu_2O$ crystals promote endothelial cell death via autophagy, elevate the level of reactive oxygen species such as superoxide and nitric oxide, and subsequently activate AMP-activated protein kinase (AMPK) through superoxide rather than nitric oxide. Consistently, the AMPK inhibitor Compound C was found to inhibit $Cu_2O$-induced AMPK activation, p62 degradation, and LC3 processing. This study provides insight on the pathophysiologic function of $Cu^+$ ions in the vascular system, where $Cu^+$ induces autophagy while $Cu^{2+}$ has no detected effect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.347-350
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• 1998

We studied relation of X-ray diffraction and charge/discharge capacity of LiMn$_2$O$_4$ cathode. LiMn$_2$O$_4$ is prepared by reacting stoichiometric mixture of LiOH.$H_2O$ and MnO$_2$ (mole ratio 1 : 2) and heating at $700^{\circ}C$, 80$0^{\circ}C$ for 24hr, 36hr, 48hr, 60hr and 72hr. Through X-ray diffraction pattern, it is analyzed that crystal structure and lattice parameter and peak ratio so on. We obtained X-ray diffraction pattern that varied lattice parameter and peak intensity by function of calcining temperature and time. Cathode active materials calcined at 80$0^{\circ}C$ for 36hr shown that (111)/(311) Peak ratio at X-ray diffraction pattern was 0.37. It means that crystal structure is formed very well in this temperature and time. In the result of charge/discharge test, cathode active material calcined at 80$0^{\circ}C$ for 36hr displayed excellent charge/discharge properties than that of cathode active materials calcined at other temperature and title. In this study, we certified that spinel structure basied cubic is formed very well at 80$0^{\circ}C$ for 36hr. In this case, (111)/(311) peak ratio at X-ray diffraction is 0.37, and charge/discharge properties is excellent than others.

• Journal of Haehwa Medicine
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• v.9 no.1
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• pp.105-112
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• 2000

Three burning space concentrating mainly on the text of ${\ll}NeiChing{\gg}$, we got this conclusion by looking at a longitudial perspective of three burning space function, nutrient & defensive qi creation, movement and numbers. 1. Longitudial movement is the law of the universe, by looking at oriental medicine by the thought of heaven and man unity we can tell that longitudial movement concept is used to analyze the physiology of our body. And we can look at our body in a cubic movement suck as top and bottom, left and right, outside and inside, internal and external, upward and downward movement. 2. In Nei Ching the concept of three burning space is seperated in to four different types of three burning space which are three burning space as a fu, three burning space as a water metabolism and excretion organ, and three burning space by its position. 3. nutrient & defensive qi's movement in the channel is the same as the twelve regular channels movement in our body, nutrient qi circulates the yang part twenty five during the day and circulates the ying part twenty five times during the night. Since channel functions corresponds with the sun, moon, and the stars the ups and downs of nutrient & defensive qi's property varies with the difference of the periods. 4. By comparing nutrient & defensive qi's production and property with three burning space's positional property, we can see that three burning space's positional property comes out from the longitudial movement of nutrient & defensive qi.

• Structural Engineering and Mechanics
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• v.40 no.1
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• pp.65-84
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• 2011

In this paper a simple mathematical model for approximate static analysis of combined system of framed tube, shear core and two outrigger-belt truss structures subjected to lateral loads is presented. In the proposed methodology, framed tube is modeled as a cantilevered beam with a box section and interaction between shear core and outrigger-belt truss system with framed tube is modeled using torsional springs placed at location of outrigger-belt truss; these torsional springs act in a direction opposite to rotation generated by lateral loads. The effect of shear lag on axial deformation in flange is quadratic and in web it is a cubic function of geometry. Here the total energy of the combined system is minimized with respect to lateral deflection and rotation in plane section. Solution of the resulting equilibrium equations yields the unknown coefficients of shear lag along with the stress and displacement distributions. The results of a numerical example, 50 storey building subjected to three different types of lateral loading obtained from SAP2000 are compared to those of the proposed method and the differences are found to be reasonable. The proposed method can be used during the preliminary design stages of a tall building and can provide a better understanding of the effects of various parameters on the overall structural behavior.

• Journal of the Korean Vacuum Society
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• v.19 no.3
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• pp.177-183
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• 2010

We report on the deposition of ZnO films using a metal organic chemical vapor deposition (MOCVD) as a function of pushing pressure and kind of reactant such as oxygen gas and water A diethylzinc (DEZ) is supplied and controlled by Ar pushing pressure through bubbling system. Oxygen gas and water are used as reactant in order to form oxidation. We knew that the surface roughness is related in the process conditions such as reactant kind and DEZ flow rate. A substrate temperature has little role of surface roughness with $O_2$ reactant. However, $H_2O$ reactant makes it to increase over the 20 times. We could get the maximum roughness of 39.16 nm at the 90 sccm of DEZ Ar flow rate, the 8 Pa of $H_2O$ vapor pressure, and the $140^{\circ}C$ of substrate temperature. In this paper, we investigated the ZnO films for the application to the light absorption layer of solar cell layer.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.7
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• pp.581-586
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• 2007

[ $(Ba_{0.57}Sr_{0.33}Ca_{0.10})TiO_3$ ] (BSCT) powders, prepared by sol-gel method, were mixed with organic vehicle and the BSCT thick films were fabricated by the screen printing method. The structural and dielectric properties were investigated as a function of the $Yb_2O_3$ doping contents. As a result of the TG-DTA, exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All BSCT thick films showed the typical XRD patterns of a cubic polycrystalline structure. The average thickness of all BSCT thick films was about $70{\mu}m$. The grain size of the BSCT thick film doped with 0.7 mol% $Yb_2O_3$ was approximately $6.2{\mu}m$. The Curie temperature and relative dielectric constant at room temperature decreased with increasing $Yb_2O_3$ amount. Relative dielectric constant and dielectric loss of the specimen doped with 0.1 mol% $Yb_2O_3$ were 4637 and 19 % at Curie temperature, respectively.

• Journal of the Korean Applied Science and Technology
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• v.14 no.3
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• pp.23-28
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• 1997

The phase diagram for the surfactant mixture system of N-dodecanocyl-N-methyl amido polyolcarboxyl alkyl ether(DGC)/N-dodecanocyl-N-alkyl glucamine(DG)/water was studied usingpolarized microscopy, differential scanning calorimetry(DSC) and rheological measurements respectively. Using polarized microscopy, the textures of liquid crystal phases obtained at various surfactantconcentrations were investigated as a function of surfactant concentration and temperature, and phasetransitions between anisotropic liquid crystal phases and isotropic liquid phase were examined usingDSC measurements. Viscoelastic properties of surfactant solutions determined between hexagonal andlamellar liquid crystal phase by rheological measurements were approximately consistent with the resultsobtained by polarized microscopy and DSC. In the study for the phase of DGC/DG(5:5 mol ratio)/water system. It could be found that the hexagonal liquid crystal phase appeared at 25${\sim}$60wt％ ofsurfactant, the cubic liquid crystal phase at 50${\sim}$65wt％ and the lamellar crystal phase at above 70wt％.