• Journal of the Korean Chemical Society
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• v.33 no.4
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• pp.337-342
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• 1989

Gasless combustion is a vigorous exothermic reaction ignited directly in solid mixture, similar to Thermit reaction. The gasless combustion synthesis has the advantages of rapid processing, energy saving, low processing cost, and high purity of products. The Ti$Si_x$(x = 0.6, 0.8, 1.0, 2.0) systems are prepared by the gasless combustion synthesis without external sintering process. The crystallographic structures of $Ti_5Si_3$, $Ti_5Si_4$ are hexagonal and tetragonal system, respectively. Those of TiSi, $TiSi_2$ are orthorhombic systems. The results of X-ray analysis agree with the JCPDS data. The combustion modes of all combustion reactions are steady state combustions, and the propagation velocities of the combustion waves of $Ti_5Si_3$, $Ti_5Si_4$ and TiSi are greater than 0.6 cm/sec and that of $TiSi_2$ is 0.28 cm/sec.

• Journal of the Korean institute of surface engineering
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• v.47 no.4
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• pp.192-197
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• 2014

Red-emitting nitride phosphors recently attracted considerable attention because of their high thermal stability and high color rendering index properties. For excellent phosphor of white light-emitting-diode, ternary nitride phosphor of $Sr/SmSi_5N_8:Eu^{2+}$ with different $Eu^{2+}$ ion concentration were synthesized by solid state reaction method. In this work, red-emitting nitride $Sr/SmSi_5N_8:Eu^{2+}$ phosphor was successfully synthesized by using multi-step high frequency induction heat treatment. The effects of molar ratio of component and experimental conditions on luminescence property of prepared phosphors have been investigated. The structure and luminescence properties of prepared $Sr/SmSi_5N_8:Eu^{2+}$ phosphors were investigated by XRD and photoluminescence spectroscopy. The excitation spectra of $Sr/SmSi_5N_8:Eu^{2+}$ phosphors indicated broad excitation wavelength range of 300 - 550 nm, namely from UV to visible area with distinct enhanced emission peaks. With an increase of $Eu^{2+}$ ion concentration, the peak position of emission in spectra was red-shifted from 613 to 671 nm. After via multi-step heat treatment, prepared phosphor showed excellent luminescence properties, such as high emission intensity and low thermal quenching, better than commercial phosphor of $Y_3Al_5O_{12}:Ce^{3+}$. Using $Eu_2O_3$ as a raw material for $Eu^{2+}$ dopant with nitrogen gas flowing instead of using commercial EuN chemical for $Sr/SmSi_5N_8:Eu^{2+}$ synthesis is one of characteristic of this work.

• Journal of the Korean Ceramic Society
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• v.48 no.6
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• pp.621-624
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• 2011

In order to deposit a homogeneous and uniform ${\beta}$-SiC films by chemical vapor deposition, we constructed the phase-diagram of ${\beta}$-SiC over graphite and silicon via computational thermodynamic calculation considering pressure(P), temperature(T) and gas composition(C) as variables in $C_3H_8-SiCl_4-H_2$ system. During the calculation, the ratio of Cl/Si and C/Si is maintained to be 4 and 1, respectively, and H/Si ratio is varied from 2.67 to 15,000. The P-T-C diagram showed very steep phase boundary between SiC+C and SiC region perpendicular to H/Si axis and also showed SiC+Si region with very large H/Si value of ~6700. The diagram can be applied not only to the prediction of the deposited phase composition but to compositional variation due to the temperature distribution in the reactor. The P-T-C diagram could provide the better understanding of chemical vapor deposition of silicon carbide.

• Korean Journal of Materials Research
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• v.9 no.8
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• pp.825-830
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• 1999

Characteristics of SiOF films deposited by a FTES/$O_2$-plasma enhanced chemical vapor deposition method have been investigated using Fourier transform infrared spectroscopy, X-ray photoelectro spectroscopy, and ellipsometry. Electrical properties such as dielectric constant, dielectric breakdown and leakage current density are investigated using C-V and I-V measurements with MIS(Au/SiOF/p-Si) capacitor structure. Stepcoverage of the films have been also characterized using scanning electron microscopy and ellipsometry. A high quality SiOF film was formed on that the flow rates of FTES and $O_2$were 300sccm, respectively. The dielectric constant of the deposited SiOF film was about 3.1. This value is lower than that of the oxide films obtained using other method. The dielectric breakdown field and leakage current are more than 10MV/cm and about $8[\times}10^{9}A/\textrm{cm}^2$, respectively. The deposited SiOF film with thickness as $2500{\AA}$ on the $0.3{\mu}{\textrm}{m}$ metal pattern shows a high step-coverage without a void.

• Journal of the Korean Vacuum Society
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• v.8 no.1
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• pp.51-54
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• 1999

Hydrogenated amorphous silicon (a-Si:H) films are fabricated by Argon radical annealing (ArRA). The deposition rate of continuously deposited a-Si:H film is 1.9 $\AA$/s. As ArRA time are increased to 0.5 and 1 minute, the deposition rate are increased to 2.8 $\AA$/s and 3.3 $\\AA$/s. The deposition rate of a-si:H films with 2 and 3 minutes ArRA time are 3.3 $\AA$/s. As the ArRA time is increased, the optical band gap and the hydrogen contents in the a-Si:H films are increased and slightly decreased. The light-induced degradation of ArRA treated a-Si:H films are less than that of continuously deposited a-Si:H film. The dark conductivity and the conductivity activation energy ($E_a$) of continuously deposited a-Si:H film are decreased to 1/25 in room temperature and increased to 0.09eV By 1 hour light soaking, respectively. The dark conductivity and $E_a$ of ArRA treated a-Si:H film decreased to 1/3 in room temperature and increased to 0.03eV by 1 hour light soaking, respectively. We could improve the stability of a-Si:H films under the light soaking by ArRA technique and discussed the microscopic process of ArRA technique.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.8
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• pp.823-829
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• 2004

In this paper, non-self-aligned SiGe HBTs with ${f}_\tau$ and${f}_max $above 50 GHz have been fabricated using an RPCVD(Reduced Pressure Chemical Vapor Deposition) system for wireless applications. In the proposed structure, in-situ boron doped selective epitaxial growth(BDSEG) and TiSi$_2$ were used for the base electrode to reduce base resistance and in-situ phosphorus doped polysilicon was used for the emitter electrode to reduce emitter resistance. SiGe base profiles and collector design methodology to increase ${f}_\tau$ and${f}_max $ are discussed in detail. Two SiGe HBTs with the collector-emitter breakdown voltages ${BV}_CEO$ of 3 V and 6 V were fabricated using SIC(selective ion-implanted collector) implantation. Fabricated SiGe HBTs have a current gain of 265 ∼ 285 and Early voltage of 102 ∼ 120 V, respectively. For the $1\times{8}_\mu{m}^2$ emitter, a SiGe HBT with ${BV}_CEO$= 6 V shows a cut-off frequency, ${f}_\tau$of 24.3 GHz and a maximum oscillation frequency, ${f}_max $of 47.6 GHz at $I_c$of 3.7 mA and$V_CE$ of 4 V. A SiGe HBT with ${BV}_CEO$ = 3 V shows ${f}_\tau$of 50.8 GHz and ${f}_max $ of 52.2 GHz at $I_c$ of 14.7 mA and $V_CE$ of 2 V.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.8
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• pp.700-704
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• 2003

This paper describes on characteristics of 2" 3C-SiC wafer bonding using PECVD (plasma enhanced chemical vapor deposition) oxide and HF (hydrofluoride acid) for SiCOI (SiC-on-Insulator) structures and MEMS (micro-electro-mechanical system) applications. In this work, insulator layers were formed on a heteroepitaxial 3C-SiC film grown on a Si (001) wafer by thermal wet oxidation and PECVD process, successively. The pre-bonding of two polished PECVD oxide layers made the surface activation in HF and bonded under applied pressure. The bonding characteristics were evaluated by the effect of HF concentration used in the surface treatment on the roughness of the oxide and pre-bonding strength. Hydrophilic character of the oxidized 3C-SiC film surface was investigated by ATR-FTIR (attenuated total reflection Fourier transformed infrared spectroscopy). The root-mean-square suface roughness of the oxidized SiC layers was measured by AFM (atomic force microscope). The strength of the bond was measured by tensile strength meter. The bonded interface was also analyzed by IR camera and SEM (scanning electron microscope), and there are no bubbles or cavities in the bonding interface. The bonding strength initially increases with increasing HF concentration and reaches the maximum value at 2.0 ％ and then decreases. These results indicate that the 3C-SiC wafer direct bonding technique will offers significant advantages in the harsh MEMS applications.ions.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.5
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• pp.814-821
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• 2010

The purpose of this study was to investigate effects of moxibustion at combined acupoints on sex and age in rats. This study measured the effects of moxibustion on small intestinal motility in rats. Cauterizing with moxa was applied 5 times to the acupoints on SI8, LI11 SP9 and ST36 under enflurane anesthesia in the groups divided with sex and age. In single acupoint groups, cauterizing with moxa on ST36 increased in all of sex and age groups. The SP9 group with 5, 6 weeks in female and 5, 8 weeks in male, the SI8 group with 5, 7 weeks in female and only 7 weeks in male, the LI11 group with only 5, 6, 7 weeks in female and only 7 weeks in male showed increasing on small intestinal motility. In combined acupoints groups, the SI8+SP9 group with 7 weeks in female and 5, 6, 8 weeks in male, the SI8+ST36 group with 5, 6 weeks in female and 8 weeks in male, the LI11+SP9 group with 5, 6 weeks in female and 6 weeks in male, the LI11+ST36 group with 5 weeks in female and 5, 6, 7 weeks in male showed increasing respectively. Although these different according to the sex and age in rats do not have a established tendency, the results suggested that the effects of combined acupoints of cauterizing with moxa have relation with individuality.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.15
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• pp.6391-6395
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• 2014

Overexpression of aquaporins (AQPs) has been reported in several human cancers. Epidermal growth factor receptor (EGFR)-extracellular signal-regulated kinases 1/2 (Erk1/2) are associated with tumorigenesis and cancer progression and may upregulate AQP expression. In this study, we demonstrated that EGF (epidermal growth factor) induces SiHa cells migration and AQP8 expression. Wound healing results showed that cell migration was increased by 2.79-1.50-fold at 24h and 48h after EGF treatment. AQP8 expression was significantly increased (3.33-fold) at 48h after EGF treatment in SiHa cells. An EGFR kinase inhibitor, PD153035, blocked EGF-induced AQP8 expression and cell migration and AQP8 expression was decreased from 1.59-fold (EGF-treated) to 0.43-fold (PD153035-treated) in SiHa. Furthermore, the MEK (MAPK (mitogen-activated protein kinase)/Erk (extracellular signal regulated kinase)/Erk inhibitor U0126 also inhibited EGF-induced AQP8 expression and cell migration. AQP8 expression was decreased from 1.21-fold (EGF-treated) to 0.43-fold (U0126-treated). Immunofluorescence microscopy further confirmed the results. Collectively, our findings show that EGF induces AQP8 expression and cell migration in human cervical cancer SiHa cells via the EGFR/Erk1/2 signal transduction pathway.

• Journal of the Korean Ceramic Society
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• v.31 no.6
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• pp.629-636
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• 1994

The ferrimagnetic glass-ceramics in the system Fe2O3-CaO-SiO2 for hyperthermia were investigated. Glasses could be prepared up to the content of 40 wt% of Fe2O3 and below the weight ratio of 1.0 of CaO/SiO2. The maximum saturation magnetization and the maximum coercive force were 29.85 emu/g and 340.1 Oe respectively, for a glass 40Fe2O3.20CaO.40SiO2 composition heat-treated at 95$0^{\circ}C$ for 8 hours. And for a glass 40Fe2O3.30CaO.30SiO2 composition the maximum saturation magnetization and the maximum coercive force were 18.47 emu/g and 374.4 Oe heat-treated at 1,00$0^{\circ}C$ and 90$0^{\circ}C$ for 8 hours respectively. The maximum hysteresis loss was 1,726.3 cal/g for a glass 40Fe2O3.20CaO.40SiO2 composition heat-treated at 95$0^{\circ}C$ for 8 hours. It was found that the ferrimagnetic Fe2O3.CaO.SiO2 glass-ceramics was little injurious to human body as results of biocompatibility test and biotoxicity test.