• Preventive Nutrition and Food Science
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• v.7 no.1
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• pp.5-11
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• 2002

The comparison of the volatile flavor components from Korean and Japanese Satsuma mandarin (C. unshiu Marcov. forma Miyagawa-wase) peel oils, isolated by cold-pressing, was performed by gas chromatography, mass-spectrometry and gas chromatography-olfactometry (GC-O). Eighty-five volatile components were identified in each oil by GC and GC-MS. Forty-three components were detected in each oil by GC-O. The total amount of monoterpene hydrocarbons was 95.88% (Korean mandarin) and 95.29% (Japanese mandarin). Limonene, ${\gamma}$-terpinene, myrcene and $\alpha$-pinene were the main components of the cold-pressed oils from the both samples. The volatile composition of the Japanese mandarin was characterized by a higher content of sesquiterpene hydrocarbons, especially bicyclogermacrene, $\alpha$-humullene and valencene. The volatile composition of two samples can easily be distinguished by the percentages of aldehydes, ketones and esters, which were found at higher levels in the Japanese mandarin. The sweet and fruity flavor was stronger in the Korean mandarin oil while herbaceous flavor was stronger in Japanese sample. From GC-O data it is suggested that the sweet and fruity flavor of the Korean mandarin resulted from terpinolene and linalool, and the herbaceous note of the Japanese mandarin from $\alpha$-humullene, nepal, ι-carvone and perill aldehyde.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.55.2-55
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• 1998

다견정 심리판-거l르마늄(JXlly-SiGe)은 TFT(thin-film transistor)와 갇븐 소자 응용에 있어서 중요한 불칠이다 .. LPCVD (low pressure chemical vapor deposition) 방법으로 비정칠 SiGc (a-SiGe) 박막올 증 착시키고 고상결정화(SPC: solid-phase crystallization)시켜 poly-SiGc옹 얻는 것은 잘 알려져 있다. 그러 나 그러나 PF'||'&'||'pound;VD-SPC 방법올 이용한 poly-SiGc의 제조에 대해서는 아직 두드러지게 연구된 바 없다. 우리단 PF'||'&'||'pound;VD 방법으로 a-SiGc 박막올 증착시키고 고상캘정화시켜 poly-SiGc올 얻었 R며, :~ 결정성, G Gc 농도, 결정핍의 평끌 크기 눔올 XRD (x-ray diffraction) 방법으호 조사하였다. 특히 pr'||'&'||'pound;VD 증착시 가판온도,Gc 함유량 등이 고상화에 미치는 영향에 대해서 조사하였다. P PECVD 장치는 터보펌프콸 사용하여 71저진공이 2xlOlongleftarrow5 Torr에 이르렀다. 가판윤 SiOOO) 웨이퍼륜 사용하고 기판 온도는 약 150- 35()"C 사이에서 변화되었다. 증착가스는 SiH4, GcH4, 112 등흘 썼다. 증착 압력과 r.f 전력용 각각 O.25ToIT와 3W로 일정하게 하였다 .. Gc 함유량(x)은 x x=O.O-O.5 사이에서 변화되었다 .. PECVD모 증착된 SiGc 박막들은 고상결정화를 위해 $\theta$X)"(:: Nz 분위기에서 24시간동안, 혹은 5OO'C에서 4열간 가열되었다. 고상결정화 후 poly-SiGc 박막은 SiGc(Ill), (220), (311) XRD 피크들올 보여주었으며, 각 피 크들은 poly-Si에 비하여 왼쪽으로 Bragg 각이 이동되었고, Vegard’slaw에 의해서 x의 값올 확 인할 수 있었다. 이것온 RBS 결과와 열치하였다. 약 150-350'C 사이에서 변화된 기판온도의 범위 에서 증착온도가 낮올수콕 견정립의 크기는 대체로 증가하는 것으로 나타났다 .. XHD로 추정된 형 균 결정립의 크기는 최대 약 3$\alpha$1m 정도였다. 또한 같끈 샘플뜰에 대해서 기판온도가 낮올수록 증착속도가 증가함옴 확인하였다 .. Gc 함유량이 x=O.1에서 x=O.5로 증가함에 따라서도 결정립의 크기와 SiGc 증착속도는 증가하는 것으로 나타났다 .. Hwang [1] , Kim[2] 둥의 연구자들은 Gc 함유 량이 증가함에 따라 결정 립 크기가 캄소하는 것올 보고하였으냐, Tsai [3] 둥은 반대의 결과플 보 고하고 Ge 힘유량의 증가시 결정립 크기의 증가에 대해 Gc의 Si보다 낮은 융점 (melting point) 올 강조한 바 있다. 결정립 크기의 증가는 대체로 SiGe 중착속도의 증가와도 관련이 있음올 볼 때, poly-SiGc의 경우에도 polv-Si의 고상화에서와 같이 증착속도가 빠를수록 최종적언 결정럽의 크기가 커지는 것으로 이해될 수도 있다 .. PECVD 증착시 증착속도의 증가는 증착된 박딱에서의 무켈서도를 증 가시킬 수 있음올 고려하면, 이라한 결파플온 p이y-SiGc의 고상결정화에서도 ploy-Si의 고상결정 화에서와 마찬가지로 초기 박막에서의 구조직 무절서도가 클수록, 고상결정화 후 결정 립의 크기 가 커칠 수 있음올 보여준다고 생각휠 수 있다,

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.810-816
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• 2009

The interactions between four Keggin-type POMs (${SiW_{12}O_{40}}^{4-},\;{PW_{12}O_{40}}^{3-},\;{SiMo_{12}O_{40}}^{4-},\;and\;{PMo_{12}O_{40}}^{3-}$) and glassy carbon (GC) and highly oriented pyrolytic graphite (HOPG) surfaces are investigated in a systematic way. Electrochemical results show that molibdate series POMs adsorb relatively stronger than tungstate POMs on GC and HOPG surfaces. Adsorption of POMs on HOPG electrode surfaces is relatively stronger than on GC surfaces. ${SiMo_{12}O_{40}}^{4-}$ species exhibits unique adsorption behaviors on HOPG surfaces. Surface-confined ${SiMo_{12}O_{40}}^{4-}$ species on HOPG surfaces exhibit unique adsorption behaviors and inhibit the electron transfer from the solution phase species. The catalytic activity of the surface-confined POMs for hydrogen peroxide electroreduction is also examined, where ${PW_{12}O_{40}}^{3-}$ species adsorbed on GC surfaces exhibits the highest catalytic efficiency among the investigated POM modified electrode systems.

• The Korea Journal of Herbology
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• v.24 no.2
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• pp.93-98
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• 2009

Objectives : Previously we reported that the roots of Panax ginseng C.A. Meyer (Araliaceae) increased sperm count and motility. also induced spermatogenesis via cAMP-responsive element modulator(CREM) activation in rat testes. In this study, for the first step of spermatogenesis in germ cell lines, the antioxidant activity of Panax ginseng were examined in mouse GC-1 spermatogonia cells. Methods : The extract was studied on diphenyl-picryl-hydrazyl (DPPH) radical scavenging activity, GC-1 cell viability by a modified MIT assay. H202-induced cytotoxicity by MIT assay and lipid peroxidation by malondialdehyde (MDA) formation. respectively. Results: The results showed that the extract scavenged DPPH radical with the IC50 being 0.631 mg/mi. The extract at concentrations of 5, and 10, 50, 100, 250 ${\mu}$g/mi increased GC-1 cell viability significantly(p < 0.05, and p < O.O1). Hydrogen peroxide-induced cytotoxicity (73.8%, p < O.O1) was blocked by the extract at concentrations of 50, and 100, 250, 500 ${\mu}$g/ml significantly (p < 0.05, and p < O.O1). The extract at concentrations of 10. and 50 ${\mu}$g/ml decreased the MDA formation on hydrogen peroxide-induced lipid peroxidation. Conclusions : In conclusion, the extract of Panax ginseng has potent antioxidant activity and increases the survival rate of GC-1 spg cells against $H_20_2$-induced cytotoxicity.

• Advances in Energy Research
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• v.3 no.2
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• pp.117-124
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• 2015

In this paper, we have reported an enhancement in thermoelectric properties of un-doped zinc oxide (ZnO) grown by molecular beam epitaxy (MBE) on silicon (001) substrate by annealing treatment. The grown ZnO thin films were annealed in oxygen environment at $500^{\circ}C-800^{\circ}C$, keeping a step of $100^{\circ}C$ for one hour. Room temperature Seekbeck measurements showed that Seebeck coefficient and power factor increased from 222 to $510{\mu}V/K$ and $8.8{\times}10^{-6}$ to $2.6{\times}10^{-4}Wm^{-1}K^{-2}$ as annealing temperature increased from 500 to $800^{\circ}C$ respectively. This observation was related with the improvement of crystal structure of grown films with annealing temperature. X-ray diffraction (XRD) results demonstrated that full width half maximum (FWHM) of ZnO (002) plane decreased and crystalline size increased as the annealing temperature increased. Photoluminescence study revealed that the intensity of band edge emission increased and defect emission decreased as annealing temperature increased because the density of oxygen vacancy related donor defects decreased with annealing temperature. This argument was further justified by the Hall measurements which showed a decreasing trend of carrier concentration with annealing temperature.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.12
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• pp.2002-2010
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• 2009

The degradation behavior of berberine is examined using GC-MS to select the fingerprint products that can be used to identify berberine dye in badly faded archaeological textiles. A total of $100^{\circ}C$ thermal and $H_2O_2/UV/O_2$ degradation systems were used to degrade berberine chloride 0.1% solution up to 408 hours. The samples were analyzed using the GC-MS. Dihydroberberine, 2-pteridinamine, 6,7-dimethyl-N-[(trimethylsilyl) oxy]-, and 8-methoxy-11-[3-methylbutyl]-11H-indolo[3,2-c]-quinoline, 5-oxide were detected as the major products of thermal degradation and identified as the fingerprint products for berberine dye at the early stage of degradation. Isobenzofuran-1,3-dione,4,5-dimethoxy-, 9H-fluorene,3,6-bis(2-hydroxyethyl)-,1,3-dioxolo[4,5-g]isoquinolin-5(6H)-one,7,8-dihydro-, and 3-tert-butyl-4-hydroxyanisole were detected as the major products generated by the $H_2O_2/UV/O_2$ degradation and identified as the fingerprint products for berberine dye under severe degradation conditions.

• Bulletin of the Korean Chemical Society
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• v.19 no.4
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• pp.417-422
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• 1998

The electrocatalytic reduction of molecular oxygen was investigated with a Co(II)-glyoxal bis(2-hydroxyanil) complex coated-glassy carbon (GC) electrode in aqueous media. The reduction of $O_2$ at the modified electrode was an irreversible and diffusion-controlled reaction. The complex coated-GC electrode demonstrated an excellent electrocatalytic effect for $O_2$ reduction in an acetate buffer solution of pH 3.2. The coated electrode made the $O_2$ reduction potential shift of 60-510 mV in a positive direction compared to the bare GC electrode depending on pH. The Co(II)-glyoxal bis(2-hydroxyanil) coated electrode converted about 51% of the $O_2$ to $H_2O_2$ via a two-electron reduction pathway, with the balance converted to H_2O$.

• Toxicological Research
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• v.18 no.1
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• pp.87-98
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• 2002

This study was conducted to evaluate the safety of a recombinant human Factor VIII(GC-$\gamma$ AHF) manufactured by Korea Green Cross Company with different technology according to the Regulation of Korean Food and Drug Administration (l 998. 12. 3). In acute toxicity test, both genders of Sprague-Dawley rats and Beagle dogs were administered intravenously with GC-$\gamma$ AHF of three doses (3,125, 625 and 125 IU/kg), and single dose of 3,125 IU/kg, respectively. No dead animal and abnormal autopsy findings were found in Control and GC-$\gamma$ AHF treated group. Therefore, the 50% lethal dose ($LD_{50}$) of GC-$\gamma$ AHF was conidered to be higher than 3,125 IU/kg in rats and dogs. In the four weeks repeated intravenous toxicity study, GC-$\gamma$ AHF was administrated intravenosly to both genders of rats and dogs with 3 doses (500, 150, 50 IU/kg). There were neither dead animals nor significant changes of body weights during the experimental Period. In addition, no significant GC-$\gamma$ AHF related changes were found in clinical sign, urinalysis and other finding. Statistically changes were observed in hematological, biochemical and organ weight parameters of treated groups: however these changes were not dose dependent. No histopathological lesion were observed in both control and treated animals. Above data suggest that no observed adverse effect level of test materials in rats and dogs might be over 500 IU/kg/day in this study. In ocular irritation test, any injury on iris, conjunctiva and cornea in rabbits were not observed. The acute ocular irritation index (A.O.I.), mean ocular irritation index (M.O.I.) and Day-7 individual ocular irritation Index (I.O.I.) of GC-$\gamma$ AHF were 0. In the primary skin Irritation test, the primary irritation index (P.I.I.) oj GC-$\gamma$ AHF were 0. Therefore, the GC-$\gamma$ AHF is considered not to have the primary skin and eye toxicity in rabbits. In active systemic anaphylaxis (ASA) test, GC-$\gamma$ AHF and GC-$\gamma$ AHF emulsified with Freund's complete adjuvant (FCA) did not induce any symptom of anaphylactic shock in guinea pigs. In passive cutaneous anaphylxis (PCA) test, after sensitization with antisera of GC-$\gamma$ AHF sensitized mice, blue spots were observed on the hypodermis of back of rats, but diameter of each spot was smaller than 5 mm in each test groups except the positive control group. Based on the results of this study, GC-$\gamma$ AHF is not conidered to have any antigenic potential. In conclusion, at levels of up to 500 IU/kg, GC-$\gamma$ AHF did not produce treatment-related toxicity under the conditions of these acute-, four week repeated-toxicity, primary skin and eye toxicity, and antigenicity test.

• Journal of the Korean Electrochemical Society
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• v.12 no.1
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• pp.75-80
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• 2009

The effect of polyoxometalate monolayers on the electrodeposition of Au nanoparticles (AuNPs) on glassy carbon (GC) surfaces was examined by electrochemical and scanning electron microscope techniques. The presence of $SiMo_{12}O^{4-}_{40}$-layers resulted in average particle sizes of ca. 60 nm, which is larger than AuNPs deposited on bare GC surfaces. AuNPs electrodeposited on $SiMo_{12}O^{4-}_{40}$-modified GC surfaces for 20 s exhibited the best electrocatalytic activity for oxygen reduction. This system exhibited similar or slightly better efficiency for oxygen reduction than a bare Au electrode. Rotating disk electrode experiments were also performed and revealed that the catalytic reduction of oxygen on AuNPs deposited on $SiMo_{12}O^{4-}_{40}$-modified GC electrodes is a two-electron process.

• Journal of the Korean Applied Science and Technology
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• v.29 no.2
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• pp.268-277
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• 2012

The thermal decomposition characteristic of waste PVC wires has been studied by using TGA and fixed-bed reactor. The experimental conditions of decomposition temperatures, air flow rates and weight ratio of CaO/PVC were considered in this work. To verify the effectiveness of CaO addition to remove HCl and toxic gases generated from thermal decomposition of PVC wire, the gaseous products obtained from the thermal decomposition of PVC were analyzed by GC/MS(Gas Chromatograph and Mass Spectrometry). To investigate the effect of CaO in thermal decomposition of PVC, liquid products were also analyzed by GC/MS. And the effect of decomposition temperature, air flow rate and CaO/ PVC weight ratio on the yield of liquid, gas and residue fraction have been also studied. From this work, it was found that the removal amount of HCl generated from thermal decomposition of PVC increased with increase of CaO addition.