• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.51.2-51.2
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• 2010

We have carried out an extensive statistical analysis based on the results of simultaneous observations of SiO and $H_2O$ masers toward 166 known SiO and $H_2O$ maser sources using KVN_Yonsei radio telescope (Kim et al.2010, ApJS submitted). We investigate the distributions of the mean velocities and the intensity ratios between SiO and $H_2O$ maser emission including those between SiO v=1 and v=2,J=1-0 transitions according to type of evolved stars. We also investigate mutual relations between SiO and $H_2O$ maser properties(total flux densities and velocity structures etc.) according to stellar pulsation phases. Most of SiO masers appear around the stellar velocity (80 % within ${\pm}5km\;s^{-1}$), while $H_2O$ masers show a different characteristic compared with SiO masers (69% within ${\pm}5km\;s^{-1}$). In addition, we investigate a correlation between $SiO/H_2O$ maser emission and AKARIFIS flux density as well as the AKARI color characteristics of SiO and $H_2O$ observational results in the AKARIFIS two-color diagram.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3133-3139
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• 2023

Neutron imaging technology as a means of non-destructive detection of materials is complementary to X-ray imaging. Silicon photomultiplier (SiPM), a new type of optical readout device, has overcome some shortcomings of traditional photomultiplier tube (PMT), such as high-power consumption, large volume, high price, uneven gain response, and inability to work in strong magnetic fields. Its application in the field of neutron detection will be an irresistible general trend. In this paper, a thermal neutron imaging detector based on ⁶LiF/ZnS scintillation screen and SiPM array readout was developed. The design of the detector geometry was optimized by geant4 Monte Carlo simulation software. The optimized detector was evaluated with a step wedge sample. The results show that the detector prototype with a 48 mm × 48 mm sensitive area can achieve about 38% detection efficiency and 0.26 mm position resolution when using a 300 ㎛ thick ⁶LiF/ZnS scintillation screen and a 2 mm thick Bk7 optical guide coupled with SiPM array, and has good neutron imaging capability. It provides effective data support for developing high-performance imaging detectors applied to the China Spallation Neutron Source (CSNS).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.70-73
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• 2001

MFIS(Metal-ferroelectric-insulator- semiconductor) structures using silicon oxynitride(SiON) buffer layers were fabricatied and demonstrated nonvolatile memory operations. Oxynitride(SiON) films have been formed on p-Si(100) by RTP(rapid thermal process) in O$_2$+N$_2$ ambient at 1100$^{\circ}C$. The gate leakage current density of Al/SiON/Si(100) capacitor was about the order of 10$\^$-8/ A/cm$^2$ at the range of ${\pm}$ 2.5 MV/cm. The C-V characteristics of Al/LiNbO$_3$/SiON/Si(100) capacitor showed a hysteresis loop due to the ferroelectric nature of the LiNbO$_3$ thin films. Typical dielectric constant value of LiNbO$_3$ film of MFIS device was about 24. The memory window width was about 1.2V at the electric field of ${\pm}$300 kV/cm ranges.

• Journal of Ocean Engineering and Technology
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• v.27 no.2
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• pp.8-12
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• 2013

Four kinds of silicon nitride composites with tri-laminate structure were prepared by stacking tapes with aligned ${\beta}-Si_3N_4$ whisker seeds. The composites were fabricated using a modified tape casting method for enhanced alignment of the whisker seeds. The relative densities of all four samples reached 99% at room temperature. The three-point flexural strengths of the samples according to the stacking sequences were measured at both room temperature and 1723 K. The high temperature strength of sample WWW was $457{\pm}14$ MPa. The fracture of sample WWW occurred mainly along the grain boundary. The room temperature strengths of samples OOO, OWO, WOW, and WWW were $430{\pm}32$ MPa, $470{\pm}19$ MPa, $700{\pm}14$MPa, and $940{\pm}14$ MPa, respectively.

• Journal of the Korean Ceramic Society
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• v.35 no.4
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• pp.364-370
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• 1998

Boron-phoshor-silicate glass was fabricated on Si substrates by FHD(Flame Hydrolysis Deposition) The microstructrue of silica soot deposited at various conditon such as composition and substrate temperature was analysed by SEM. After consolidation the refractive index and composition of the silica layer were in-vestigated. For refractive index control B, P and Ge were used as additive elements while B and Ge oxides are easily mixed into $SiO_2$, P oxide($B_2O_3$) doping is difficult because of the volatile property due to low melt-ing point. Boron-phosphorous-silicate glass (BPSG) layer were fabricated using bertical torch and optimized flame temperature substrate temperature and distance of torch and substrate. P concentration of BPSG lay-er measured 3.3 Wt% and the consolidation temperature was lower than $1180^{\circ}C$. The measured refractive index of BPSG silica layer in $1.55\;\mu\textrm{m}$ wavelength was $1.4480{\pm}1{\times}10^{-1}$ and the thickness was $22{\pm}1\;\mu\textrm{m}$.

• The Journal of Korean Medicine
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• v.23 no.3
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• pp.96-103
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• 2002

Objectives : Dyspnea is one of the most common symptoms that we meet, but so far there has been no research about the effects of acupuncture therapy on it. This study was performed in order to evaluate the effect of acupuncture therapy on dyspnea by means of using objective indexes. Methods : The effect of acupuncture therapy was assessed by analyzing the pulmonary function test (PFT) in 10 patients, who had suffered from dyspnea and had pain at the acupuncture point Tian-zong (SI11) when it was compressed by a finger, at our outpatient department. Each patient was treated with acupuncture therapy at both sides of Tian-zong. We compared the results of pre-treatment and post-treatment PFTs, including forced vital capacity (FVC), forced expiratory volume in one second (FEV 1.0), and peak expiratory flow rate (PEFR). Results : FVCs of pre-treatment and post-treatment PFTs were $2.23{\pm}0.34(L)$ and $2.40{\pm}0.36(L)$ respectively (P<0.01). FEV1.0s of pre-treatment and post-treatment PFTs were $1.54{\pm}0.37(L)$ and $1.65{\pm}0.41(L)$ respectively (p<0.05). PEFRs of pre-treatment and post-treatment PFTs were $3.41{\pm}1.26(L)$ and $3.93{\pm}1.42(L)$ respectively (p<0.05). Conclusions From the above data, we conclude that FVC, FEV1.0, and PEFR in dyspneic patients have been improved after acupuncture therapy of Tian-zong, so acupuncture therapy of Tian-zong may relieve the dyspnea symptom.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.16 no.5
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• pp.83-92
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• 2013

The present study documented the characteristics of habitats and nests of Goshawk [Northern goshawk] Accipiter gentilis breeding in Gongju-si, Chungcheongnam-do and Haepyung, Kyungsangbuk-do, Eumsung-gun, Chungju-si, Chungcheongbuk-do from April 2007 to August 2011. Breeding habitat includes of mixes and deciduous trees and ravine forest, ranging from small to large areas and it used make a new nest and fix up the old nest at Goshawk. Goshawk make nests on Japanese larch Larix leptolepis, Japanese red pine Pinus densiflora and Pitch pine Pinus rigidae of $15.8{\pm}2.36m$ (range=7.4~18.7m) in height and $34.6{\pm}7.38cm$ (range=20.8~47.4cm) in diameter-at-breast height (DBH). It has $135.8{\pm}3.37cm$ in outer diameter of nest, $26.2{\pm}2.39cm$ in inner diameter, $7.1{\pm}1.41cm$ of depth, and $3.1{\pm}0.40Kg$ of weight. Breeding habitat (n=13) has 5~7 nests. It has 7 (53.8%) nest in fix up the old nest and 4 (30.8%)nests in make a new nest.

• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.319-324
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• 2019

A depth-encoding detector module with silicon photomultipliers(SiPMs) using two layers of scintillation crystal array was designed, and the position measurement capability was verified using DETECT2000. The depth of interaction of the crystal pixels with the gamma rays was tracked through the image acquired with the combination of surface treatment of the crystal pixels and reflectors. The bottom layer was treated as a reflector except for the optically coupled surfaces, and the crystals of top layer were optically coupled each other except for the outer surfaces so that the light sharing was made easier than the bottom layer. Flood images were obtained through the combination of specular reflectors and random reflectors, grounded and polished surfaces of crystal pixels, and the positions at which layer images were generated were measured and analyzed. The images were reconstructed using the Anger algorithm, whose the SiPM signals were reduced as the 16-channels to 4-channels. In the combination of the grounded surface and all reflectors, the depth positions were discriminated into two layers, whereas it was impossible to separate the two layers in the all polished surface combinations. Therefore, using the combination of grounded surface crystal pixels and reflectors could improve the spatial resolution at the outside of the field of view by measuring the depth position in preclinical positron emission tomography.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2001.11a
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• pp.40-40
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• 2001

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.295-298
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• 1989

Using the anisotropic etching characteristics or $N_2H_4-H_2O$ solution, Si diaphragm was fabricated for the integrated sensor. The optimal composition and temperature of the solution in Si etching process was established to be 50mol% $N_2H_4$ in water at $105{\pm}2^{\circ}C$ for both higher etch rate(=$2.6{\mu}m/min$) and better surface quality of etched {100} planes. Under the optimal etching condition, the electrochemical etch stop technique was employed to form Si diaphragm for pressure sensor and diaphragm thickness was exactly controlled to $20{\pm}2{\mu}m$.