• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.243-245
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• 2013

Topological insulator (TI) has non-trivial metallic surface states and has provoked many studies of property of this metarial. One of TI, $Bi_2Se_3$ is the promising metarial due to application of quantum devices. We investigate the effect of Ag adatom in the $Bi_2Se_3$ (111) surface. The silver atom prefers to locate within the vdW gap between the QLs rather than on the top surface. The effect of Ag adsorption is the rise of the Fermi level implying that the adsorbed Ag atoms behave like electron donors.

• Journal of Powder Materials
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• v.19 no.6
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• pp.442-445
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• 2012

The quantum dots (QD) have unique electrical and optical properties due to quantum dot confinement effect. The optical properties of QDs are decided by various synthesis conditions. In a prior QDs study, a study on the QDs size with synthesis condition such as synthesis time and temperature is being extensively researched. However, the research on QDs size with composition ratio has hitherto received scant attention. In order to evaluate the ratio dependence of CdSe crystal, synthesis ratio of Se precursor is changed from 16.7 mol%Se to 44 mol%Se. As the increasing Se ratio, the band gap was increased. This is caused by red shift of emission. We confirmed optical property of CdSe QDs with composition ratio.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.939-942
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• 2008

Photoelectrochemical deposition of CdZnSe thin films on the Se-modified Au electrode using electrochemical quartz crystal microgravimetry (EQCM) and voltammetry is described. Corrosion of pre-deposited Se electrodes by illumination at a fixed potential resulted in $Se^{2-}$ species, which was manifest from the EQCM frequency changes. $Se^{2-}$ species generated from the photocorrosion reacted with $Cd^{2+}$ and $Zn^{2+}$ ions in the electrolyte to form CdZnSe films on the Au electrode. The effect of electrolyte composition on the composition and band gap of CdZnSe films was studied in detail. Also, photoelectrochemistry, EDX, Raman spectroscopy were used for the characterization of CdZnSe thin films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.352-356
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• 2003

A stoichiometric mixture of evaporating materials for $CuGaSe_2$ single crystal am films was prepared from horizontal electric furnace. Using extrapolation method of X-ray diffraction patterns for the polycrystal $CuGaSe_2$, it was found tetragonal structure whose lattice constant $a_0$ and $c_0$ were $5.615\;{\AA}\;and\;11.025\;{\AA}$, respectively. To obtain the single crystal thin films, $CuGaSe_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $610^{\circ}C$ and $450^{\circ}C$, respectively, The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuGaSe_2$ single crystal thin films measured with Hall effect by van der Pauw method are $9.24{\times}10^{16}\;cm^{-3}$ and $295\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CuGaSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)\;:\;1.7998\;eV\;-\;(8.7489\;{\times}\;10^{-4}\;eV/K)T^2(T\;+\;335\;K)$. After the as-grown $CuGaSe_2$ single crystal thin films was annealed in Cu-, Se-, and Ga-atmospheres, the origin of point defects of $CuGaSe_2$ single crystal thin films has been investigated by the photoluminescence(PL) at 10 K. The native defects of $V_{CU}$, $V_{Se}$, $CU_{int}$, and $Se_{int}$, obtained by PL measurements were classified as a donors or accepters type. And we concluded that the heat-treatment in the Cu-atmosphere converted $CuGaSe_2$ single crystal thin films to an optical n-type. Also, we confirmed that Ga in $CuGaSe_2/GaAs$ did not form the native defects because Ga in $CuGaSe_2$ single crystal thin films existed in the form of stable bonds.

• Journal of the Korean Solar Energy Society
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• v.23 no.2
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• pp.59-70
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• 2003

A stoichiometric mixture of evaporating materials for $CuGaSe_2$ single crystal thin films was prepared from horizontal electric furnace. Using extrapolation method of X-ray diffraction patterns for the polycrystal $CuGaSe_2$, it was found tetragonal structure whose lattice constant $a_0$ and $c_0$ were $5.615{\AA}$ and $11.025{\AA}$, respectively. To obtain the single crystal thin films, $CuGaSe_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $610^{\circ}C$ and $450^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuGaSe_2$ single crystal thin films measured with Hall effect by van der Pauw method are $5.01\times10^{17}cm^{-3}$ and $245cm^2/V{\cdot}s$ at 293K. respectively. The temperature dependence of the energy band gap of the $CuGaSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g$(T)=1.7998 eV-($8.7489\times10^{-4}$ eV/K)$T^2$/(T+335K). After the as-grown $CuGaSe_2$ single crystal thin films was annealed in Cu-, Se-, and Ga-atmospheres, the origin of point defects of $CuGaSe_2$ single crystal thin films has been investigated by the photoluminescence(PL) at 10 K. The native defects of $V_{CU},\;V_{Se},\;Cu_{int}$ and $Se_{int}$ obtained by PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the Cu-atmosphere converted $CuGaSe_2$ single crystal thin films to an optical n-type. Also, we confirmed that Ga in $CuGaSe_2$/GaAs did not form the native defects because Ga in $CuGaSe_2$ single crystal thin films existed in the form of stable bonds.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.1
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• pp.61-66
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• 2006

This experiment was conducted to evaluate the effects of different selenium (Se) products (inorganic, organic A, organic B) added at two supplemental dietary Se levels (0.1 and 0.3 mg/kg) on growth performance, nutrient digestibility and Se retention in growing-finishing pigs. A $3{\times}2$ factorial arrangement of treatments was used in a RCB design, with a non-Se-fortified basal diet serving as the negative control. A total of 56 crossbred pigs (28 male and 28 female pigs) initially weighing an average $28.45{\pm}0.53kg$ BW were allotted to each treatment with four pigs per pen on the basis of sex and weight. Two pigs per pen were selected and bled from the anterior vena cava at 3- weekly intervals to analyze Se concentration. In the growing phase (0-6 weeks), increased ADFI was observed when pigs were fed organic Se compared to those fed the control diet or inorganic Se treatment (p<0.05). Pigs fed inorganic Se had a great ADFI than pigs fed organic Se (p<0.05) in the late finishing phase (7-12 weeks), although there were no differences in whole period ADFI between organic or inorganic Se products. During 12 weeks of the whole experimental period, serum Se concentration increased linearly when dietary Se level increased regardless of Se products (p<0.05). Both dietary Se source (p<0.05) and Se level (p<0.01) influenced the Se concentration of various pig tissues at end of this experiment and Se content was the highest in the kidney. For the determination of nutrient digestibility, a metabolic trial was conducted in 3 replicates in randomized complete block (RCB) design. A total of 21 barrows ($50.21{\pm}0.62kg$ of average BW) were used in the metabolic study. Selenium supplementation had no effect on nutrient digestibility except for crude protein. Crude protein digestibility increased with dietary supplementation of organic Se (A) compared with other forms of Se products or control diet (p<0.05). Consequently, this experiment indicated that dietary Se products and levels had no effect on growth performance of pigs. Se concentration in tissues and serum was increased in proportion to dietary Se level, especially when organic Se was provided. Although pigs were fed organic forms of Se, bioavailability of organic forms varied among products, consequently bioactivity of organic products to the animals should be evaluated before practical application in animal feed.

• Journal of the Korean Applied Science and Technology
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• v.40 no.4
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• pp.589-605
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• 2023

Soy isoflavones are attracting attention from postmenopausal women because of their beneficial effects on menopausal symptoms. This study was investigated whether a combination of soy isoflavone genistein and swimming exercise (Gen+SE) would have a beneficial synergistic effect on obesity and improvement of liver function compared to the genistein only (Gen) and swimming exercise only (SE) in ovariectomized mice. Ovariectomized mice were randomly divided into control group (Con), Gen, SE, and Gen+SE, and were fed a high-fat diet for 8 weeks. As a result of examining the body weight, weight of white adipose tissue, lipid accumulation of liver, and serum ALT and AST levels, both Gen and SE decreased compared to Con, and Gen+SE decreased more than compared to Gen and SE. The expression of inflammatory cytokines MCP-1, IL-6 and TNF-𝛼 genes in liver decreased in both Gen and SE compared to Con, and were further decreased in Gen+SE compared to Gen and SE. But The expression of adiponectin showed opposite results. The expression of fatty acid oxidation related genes in liver increased in both Gen and SE compared to Con, and were more effectively than increased in Gen+SE compared to Gen and SE. Therefore this study suggests that the interaction between soy isoflavone and swimming exercise is very effective controlling obesity and recovering decreased liver function, and this is caused by promoting fatty acid oxidation in the liver in ovariectomized mice.

• The Journal of Korean Obstetrics and Gynecology
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• v.20 no.2
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• pp.205-213
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• 2007

Purpose: The purpose of this study is to report the effect of Korean Medicine therapy to chronic pelvic inflammatory disease. Methods: A 34 years old woman, who suffered from chronic pelvic inflammatory disease was admitted to the OBGY department of Se-Myung University, Je-Cheon. In the beginning of treatment, she had pain and cold in the lower abdomen, dysuria, displeasure of sexual intercourse, etc. She received Korean Medicine therapies such as herbal medicine, moxibustion, acupuncture and got good result from them. Results: As a result, symptoms are remarkably alleviated. Conclusion: The present study suggests that Korean Medicine therapies have significant effect on chronic pelvic inflammatory disease.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.12
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• pp.71-79
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• 1994

In this paper, $As_{40}Se_{50-x}S_[x}Ge_{10}$(x=0, 25, 35, at.%) bulk and thin films, to develope device of reversible hologram, proved amorphous by X-RD analysis. On the thin films with composition rate, as Se-doped-quantity increased, absorption edge shifted to long wavelength, and we found that reversible photodarkening effect occurred when thin films are exposed and annealed. Optical energy gap was larger when thin films are annealed than exposed. In this effect thin films structurally stabilized by annealing. It is to formed grating hologram by the bragg method on the $As_{40}Se_{15}S_[35}Ge_{10}$ thisn films with the best transmittance properties As polariging angle grew larger, we found that maximum diffraction efficiency became smaller, and obtained it of 4.5% on the thin fim thicknesss of 0.6 m, polarizing angle of 40$^[\circ}$ and exposing for 20sec.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.6
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• pp.199-204
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• 1983

In this paper, we investigated that the Al-Amorphous Se-Al structure had a large photovoltage and a Dark EMF (DEMF). This DEMF phenomena did not show just after the fabrication of a sample. However, it was shown after a few days, and it was increased with time, and was saturated after 30 days. Just after the fabrication of a sample, by appling the positive voltage on a sample for 100mins, we observed almost the same effect as had shown in a aging experiment. As the results, we found that Al3+ ions has related to a DEMF by migrating into amorphous Se, and form a trap in amorphous Se. We have also observed the photocapacitance effect to identify this trap formation.