• Applied Chemistry for Engineering
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• v.29 no.4
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• pp.425-431
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• 2018

Composite particles of porous silica and cerium oxide nanoparticles blocking UV/blue light were prepared through a dry coating process. Various composite particles were prepared by varying conditions such as the mixing ratio of cerium oxide and silica, and the chamber rotating speed of mechano fusion system. The surface morphology of the composite particles was observed with SEM and the composition was analyzed using X-ray fluorescence (XRF). When the cerium oxide/silica composite particles were dispersed in water, the transparency and dispersion stability of the colloidal solution were improved. In addition, the fluidity and spreadability of the particle powder were enhanced by making composite particles. These results show that cerium oxide/silica composite particles can be used as functional cosmetic ingredients for UV/blue light protection.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.11
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• pp.914-920
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• 2000

When the charge-trap type SONOS(polysilicon-oxide-nitride-oxide-semiconductor) cells are used to flash memory, the tunneling program/erase condition to minimize the generation of interface traps was investigated. SONOSFET NVSM(Nonvolatile Semiconductor Memory) cells were fabricated using 0.35 ㎛ standard memory cell embedded logic process including the ONO cell process, based on retrograde twin-well, single-poly, single metal CMOS(Complementary Metal Oxide Semiconductor) process. The thickness of ONO triple-dielectric for the memory cell is tunnel oxide of 24 $\AA$, nitride of 74 $\AA$, blocking oxide of 25 $\AA$, respectively. The program mode(V$\_$g/=7, 8, 9 V, V$\_$s/=V$\_$d/=-3 V, V$\_$b/=floating) and the erase mode(V$\_$g/=-4, -5, -6 V, V$\_$s/=V$\_$d/=floating, V$\_$b/=3 V) by MFN(Modified Fowler-Nordheim) tunneling were used. The proposed programming condition for the flash memory of SONOSFET NVSM cells showed less degradation(ΔV$\_$th/, S, G$\_$m/) characteristics than channel MFN tunneling operation. Also, the program inhibit conditins of unselected cell for separated source lines NOR-type flash memory application were investigated. we demonstrated that the phenomenon of the program disturb did not occur at source/drain voltage of 1 V∼12 V and gate voltage of -8 V∼4 V.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.28 no.4
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• pp.287-294
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• 2006

Vascular thrombosis and ischemic necrosis still remain the most significant threats to the survival of free flaps. To date, neutrophils have been implicated in the pathogenesis of postischemic injury. Several studies have demonstrated that modulating the neutrophil response to ischemia-reperfusion injury can decrease the extent of the injury. In addition, some authors noticed that mast cell counts were also increased in flaps exposed to state of ischemia/reperfusion. So, we designed to evaluate the role of mast cells in ischemia/reperfusion by blocking histamine and to compare the effect of L-arginine, a nitric oxide precursor which is known to prevent neutrophil-mediated tissue injury. Epigastric island skin flaps were elevated in 30 rats and rendered ischemic. Thirty minutes prior to reperfusion, the rats were treated with intraperitoneal saline, diphenhydramine, cimetidine, and L-arginine. The necrosis rate of flap at 7 days, the number of neutrophils and mast cells at 20 hours were evaluated. In conclusion, histamine receptor blockers as well as L-arginine significantly decreased flap necrosis in a rat skin island ischemia-reperfusion flap model, but the protective effect was not significantly different in both agent groups.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.267-270
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• 2001

A new small scaling Lateral Trench Insulated Gate Bipolar Transistor (SSLTIGBT) was proposed to improve the characteristics of the device. The entire electrode of the LTIGBT was replaced with a trench-type electrode. The LTIGBT was designed so that the width of device was no more than 10$\mu\textrm{m}$. The latch-up current densities were improved by 4.5 and 7.6 times, respectively, compared to those of the same sifted conventional LTIGBT and the conventional LTIGBT which has the width of 17$\mu\textrm{m}$. The enhanced latch-up capability of the SSLTIGBT was obtained due to the fact that the hole current in the device reaches the cathode via the p+ cathode layer underneath the n+ cathode layer, directly. The forward blocking voltage of the SSLTIGBT was 125 V. At the same size, those of the conventional LTIGBT and the conventional LTIGBT with the width of 17$\mu\textrm{m}$ were 65 V and 105 V, respectively. Because the proposed device was constructed of trench-type electrodes, the electric field in the device were crowded to trench oxide. Thus, the punch through breakdown of LTEIGBT occurred late.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.338-341
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• 2002

A new small size Lateral Trench Electrode Insulated Gate Bipolar Transistor (LTEIGBT) is proposed and fabricated to improve the characteristics of device. The entire electrode of LTEIGBT is placed to trench type electrode. The LTEIGBT is designed so that the width of device is 19$\mu\textrm{m}$. The latch-up current density of the proposed LTEIGBT is improved by 10 and 2 times with those of the conventional LIGET and LTIGBT The forward blocking voltage of the LTEIGBT is 130V. At the same size, those of conventional LIGBT and LTIGBT are 60V and 100V, respectively. Because that the electrodes of the proposed device is formed of trench type, the electric field in the device are crowded to trench oxide. We fabricated He proposed LTEIGBT after the device and process simulation was finished. When the gate voltage is applied 12V, the forward conduction currents of the proposed LTEIGBT and the conventional LIGBT are 80mA and 70mA, respectively, at the same breakdown voltage of 150V,

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.469.2-469.2
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• 2014

All-solid-state solar cell based on Chloride doped organometallic halide perovskite, (CH3NH3)PbIxCl3-x, has achieved a highly power conversion efficiency (PCE) to over 15% [1] and further improvements are expected up to 20% [2]. In this way, solar cells using novel light absorbing perovskite material are actively being studied as a next generation solar cells. However, making solution-process require high temperature up to $500^{\circ}C$ to form compact hole blocking layer and sinter the mesoporous oxide scaffold layer. Because of this high temperature process, fabrication of flexible solar cells on plastic substrate is still troubleshooting. In this study, we fabricated highly efficient flexible perovskite solar cells with PCE in excess of 11%. Atomic layer deposition (ALD) is used to deposit dense $TiO_2$ as hole blocking layer on ITO/PEN substrate. The all fabrication process is done at low temperature below $150^{\circ}C$. This work shows that one of the important blueprint for commercial use of perovskite solar cells.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.9
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• pp.758-763
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• 2002

A new small size Lateral Trench Electrode Insulated Gate Bipolar Transistor (LTEIGBT) is proposed and fabricated to improve the characteristics of device. The entire electrode of LTEIGBT is placed to trench type electrode. The LTEIGBT is designed so that the width of device is 19w. The latch-up current density of the proposed LTEIGBT is improved by 10 and 2 times with those of the conventional LIGBT and LTIGBT. The forward blocking voltage of the LTEIGBT is 130V. At the same size, those of conventional LIGBT and TIGBT are 60V and 100V, respectively. Because the electrodes of the proposed device is formed of trench type, the electric field in the device are crowded to trench oxide. When the gate voltage is applied 12V, the forward conduction currents of the proposed LTEIGBT and the conventional LIGBT are 80mA and 70mA, respectively, at the same breakdown voltage of 150V.

• Transactions on Electrical and Electronic Materials
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• v.2 no.4
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• pp.15-18
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• 2001

A new small scaling Lateral Trench Insulated Gate Bipolar Transistor (SSLTIGBT) was proposed to improve the characteristics of the device. The entire electrode of the LTIGBT was replaced with a trench-type electrode. The LTIGBT was designed so that the width of device was no more than 10 ${\mu}{\textrm}{m}$. The latch-up current densities were improved by 4.5 and 7.6 times, respectively, compared to those of the same sized conventional LTIGBT arid the conventional LTIGBT which has the width of 17 ${\mu}{\textrm}{m}$. The enhanced latch-up capability of the SSLTIGBT was obtained due to the fact that the hole current in the device reaches the cathode via the p+ cathode layer underneath the n+ cathode layer, directly. The forward blocking voltage of the SSLTIGBT was 125 V. At the same size, those of the conventional LTIGBT and the conventional LTIGBT with the width of 17 ${\mu}{\textrm}{m}$ were 65 V and 105 V, respectively. Because the proposed device was constructed of trench-type electrodes, the electric field In the device were crowded to trench oxide. Thus, the punch through breakdown of LTEIGBT occurred late.

• Journal of Powder Materials
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• v.25 no.1
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• pp.1-6
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• 2018

Uniform $TiO_2$ blocking layers (BLs) are fabricated using ultrasonic spray pyrolysis deposition (USPD) method. To improve the photovoltaic performance of dye-sensitized solar cells (DSSCs), the BL thickness is controlled by using USPD times of 0, 20, 60, and 100 min, creating $TiO_2$ BLs of 0, 40, 70, and 100 nm, respectively, in average thickness on fluorine-doped tin oxide (FTO) glass. Compared to the other samples, the DSSC containing the uniform $TiO_2$ BL of 70 nm in thickness shows a superior power conversion efficiency of $7.58{\pm}0.20%$ because of the suppression of electron recombination by the effect of the optimized thickness. The performance improvement is mainly attributed to the increased open-circuit voltage ($0.77{\pm}0.02V$) achieved by the increased Fermi energy levels of the working electrodes and the improved short-circuit current density ($15.67{\pm}0.43mA/cm^2$) by efficient electron transfer pathways. Therefore, optimized $TiO_2$ BLs fabricated by USPD may allow performance improvements in DSSCs.

• Archives of Pharmacal Research
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• v.29 no.11
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• pp.990-997
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• 2006

Sarcococca saligna is a shrub that is traditionally used for its medicinal properties in Pakistan. In this study we report the cardio-suppressant, vasodilator and tracheal relaxant activities of the aqueous-methanolic extract (Ss.Cr) of the plant. Ss.Cr, that tested positive for the presence of saponins, flavonoids, tannins, phenols, and alkaloids, exhibited a dose-dependent (0.3-5 mg/mL) negative inotropic and chronotropic effect on the isolated guinea-pig atrium which was resistant to atropine ($1\;{\mu}M$) and aminophylline ($10\;{\mu}M$) pretreatment. In rabbit thoracic aorta, Ss.Cr dose-dependently (0.1-3 mg/mL) relaxed the high $K^{+}$ (80 mM) and phenylephrine ($PE,\;1\;{\mu}M$)-induced contractions, indicating a possible $Ca^{++}$ channel blocking (CCB) effect. When tested against PE ($1\;{\mu}M$) control peaks in normal $Ca^{++}\;and\;Ca^{++}$-free Kreb's solution, Ss.Cr exhibited dose-dependent (0.1-3 mg/mL) inhibition, being more potent in relaxing the PE responses in $Ca^{++}$-free Kreb's solution, thus indicating specific blockade of $Ca^{++}$ release from the intracellular stores. Ss.Cr also relaxed the agonist-induced contractions in: a) rat aorta irrespective of the presence of endothelium or nitric oxide synthase inhibitor L-NAME and b) rabbit and guinea-pig tracheal strips. The data shows that Ss.Cr possesses possible $Ca^{++}$ channel blocking activity which might be responsible for its observed cardio-suppressant, vasodilator and tracheal relaxant effects though more tests are required to confirm this $Ca^{++}$ channel blocking effect.