• 한국식품과학회지
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• 제20권2호
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• pp.200-204
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• 1988

생체(生體) 마늘의 영하 조건에서의 저장 가능성을 검토하기 위하여 생체 인편에 대한 내한특성(耐寒特性)을 조사한 결과 마늘 인편의 빙점은 $-4^{\circ}C{\sim}-5^{\circ}C$로 산지별로 차이가 크지 않았으나 수확 후 처리 조건 및 저장 기간의 경과에 따라 다소 차이를 보여 예건전(豫乾前) $-3.5^{\circ}C$, 예건후(豫乾後) $-4.5^{\circ}C$, 저장 5개월 후 $-5.5^{\circ}C$로 나타났다. 그러나 동결치사한 마늘 인편의 빙점(氷點)은 $-2.5^{\circ}C$로 생체조직(生體組織)에 비하여 높았다. 생체(生體)마늘을 $-4^{\circ}C{\sim}-15^{\circ}C$사이의 5개 저장고(貯藏庫)에서 동결치사율(凍結致死率)을 조사(調査)하였던 바 $-4^{\circ}C$구에서는 0%, $-6.5^{\circ}C$구에서는 건전율(率) 80% 치사율(致死率) 20%였으며 $-15^{\circ}C$구에서는 70%의 치사율(致死率)을 나타내고 있어 생체(生體)마늘의 동결치사(凍結致死) 임계온도는 $-6.0^{\circ}C$ 정도로 판단되었다. 저장온도(貯藏溫度) 조건(條件)에 따른 호흡률의 변화는 온도(溫度) 하강($-4^{\circ}C$까지)에 따라 감소하는 경향을 보였고$Q_{10}$값은 $-4.0^{\circ}C{\sim}5.0^{\circ}C$ 범위에서 2, $5^{\circ}C{\sim}15^{\circ}C$에서 3, $15^{\circ}C{\sim}37^{\circ}C$에서 1.2를 보였다. 기존의 저온 저장 조건으로 제시된 ASHRAE의 $0^{\circ}C$, 75% RH, 빙점 $0.8^{\circ}C$는 한국산 마늘의 경우 재검토되어야 할 것으로 사료된다.

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2000년도 추계학술대회
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• pp.49-53
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• 2000

• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2000년도 추계학술대회
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• pp.67-70
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• 2000

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.199-200
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• 2009

This paper describes the electrical properties of polycrystalline (poly) 3C-SiC thin films with different nitrogen doping concentrations. The in-situ-doped poly 3C-SiC thin films were deposited by using atmospheric-pressure chemical vapor deposition (APCVD) at $1200^{\circ}C$ with hexamethyldisilane (HMDS: $Si_2$ $(CH_3)_6)$ as a single precursor and 0 ~ 100 sccm of $N_2$ as the dopant source gas. The peaks of the SiC (111) and the Si-C bonding were observed for the poly 3C-SiC thin films grown on $SiO_2/Si$ substrates by using X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) analyses, respectively. The resistivity of the poly 3C-SiC thin films decreased from $8.35\;{\Omega}{\cdot}cm$ for $N_2$ of 0 sccm to $0.014\;{\Omega}{\cdot}cm$ with $N_2$ of 100 sccm. The carrier concentration of the poly 3C-SiC films increased with doping from $3.0819\;{\times}\;10^{17}$ to $2.2994\;{\times}\;10^{19}\;cm^{-3}$, and their electronic mobilities increased from 2.433 to $29.299\;cm^2/V{\cdot}S$.

• Journal of Nutrition and Health
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• 제29권1호
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• pp.122-133
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• 1996

As ciarette smoking adversely affects vitamin C metabolism in humans, smokers need substantially more vitamin C intake than do non-smokers to achieve similar serum vitamin C concentration. To provide the basic information currently available for the determination of vitamin C requirement for Korean smokers, we investigated the differences the serum vitamin C values between smokers(n=53) and non-smokers(n=62) in relation to their intake of the vitamin through diet in 115 male college students, who had not been using vitamin C supplements. Dietary intakes of vitamin C were determined by a 24-hour recall, and serum vitamin C was determined using the 2, 4-dinitrophenylhydrazine method. The mean vitamin C intakes of smokers and non-smokers were consuming less than 75% of the Koeran RDA for vitamin c in their diet. Smokers consumed yellow and green leafy vegetables more often (P=0.02) and fresh fruits less often(P=0.006) than non-smokers. The mean serum vitamin C concentration of smokers consuming the same amounts of vitamine C as non-smokers, 64.3 umol/1, were 20% lower than for non-smokers, 80.1 umol/l(P<0.05). The risk of low serum vitamin C concentration (LoC) among smokers were 3.8% compared with 1.6% in non-smokers, and the odd ratio for LoC risk was 2.43. There were no correlations between dietary and serum vitamin C for smokers and non-smokers. It was concluded that smokers might require at least 20% more vitamin C to reach the same concentration comparable to non-smokers.

• 한국전기전자재료학회논문지
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• 제21권6호
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• pp.493-498
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• 2008

This Paper describes the Raman scattering characteristics of polycrystalline (Poly) 3C-SiC thin films, in which they were deposited on AlN buffer layer by APCVD using hexamethyldisilane (MHDS) and carrier gases (Ar+$H_2$). When the Raman spectra of SiC films deposited on the AlN layer of before and after annealing were worked according to growth temperature, D and G bands of graphite were measured. It can be explained that poly 3C-SiC films admixe with nanoparticle graphite and its C/Si rate is higher than ($C/Si\;{\approx}\;3$) that of the conventional SiC, which has no D and G bands related to graphite. From the Raman shifts of 3C-SiC films deposited at $1180^{\circ}C$ on the AlN layer of after annealing, the biaxial stress of poly 3C-SiC films was obtained as 896 MPa.

• Journal of Ginseng Research
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• 제6권1호
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• pp.11-16
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• 1982

New shoot growth of Panax ginseng root was investigated comparing with burley and soybean from l0$^{\circ}C$ to 30$^{\circ}C$ under dark. Shoot growth ceased by 12days at 30$^{\circ}C$ and optimum temperature appeared to be 15$^{\circ}C$/20$^{\circ}C$ (15hrs/9 hrs) , and 15$^{\circ}C$/15$^{\circ}C$ for ginseng. Shoot growth seems to be Poor below l0$^{\circ}C$. Temperature for maximum growth 20$^{\circ}C$/20$^{\circ}C$ for barley and 20$^{\circ}C$ /25$^{\circ}C$ for soybean. Barley did not germinate above 25$^{\circ}C$/25$^{\circ}C$, but grow better than soybean below 15$^{\circ}C$/25$^{\circ}C$. Fresh weight of 2 weeks suggesting cessation of water uptake at higher temporal use. Ginseng showed greater root ply s shoot of ginseng was linearly increased at 15$^{\circ}C$ but did not increased at 25$^{\circ}C$ after occurence of die-back of new shoot or root rot above 25$^{\circ}C$.

• 한국세라믹학회지
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• 제32권10호
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• pp.1194-1202
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• 1995

The influences of TiC additions to the α-SiC on microstructural, mechanical, and electrical properties were investigated. Electrical discharge machinability of SiC-TiC composites was also studied. Samples were prepared by adding 30, 45, 60 wt.% TiC particles as a second phase to a SiC matrix. Sintering of SiC-TiC composites was done by hot pressing under a vacuum atmospehre from 1000 to 2000℃ with a pressure of 32 MPa and held for 90 minutes at 2000℃. Samples obtained by hot pressing were fully dense with the relative densities over 99% except 60wt.% TiC samples. Flexural strength and fracture toughness of the samples were increased with the TiC content. In case of SiC samples containing 45 wt.% TiC, the fracture toughness showed 90% increase compared to that of monolithic SiC sample. The crack propagation and crack deflection were observed with a SEM for etched samples after Vicker's indentation. The electrical resistivities of SiC-TiC composites were measured utilizing the four-point probe. The electrical dischage machining of composites was also conducted to evaluate the machinability.

• 한국전기전자재료학회논문지
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• 제20권3호
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• pp.234-239
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• 2007

This paper describes the TiW ohmic contact characteristics under the surface treatment of the polycrystalline 3C-SiC thin film grown on $SiO_2/Si(100)$ wafers by APCVD. The poly 3C-SiC surface was polished by using CMP(chemical mechanical polishing) process and then oxidized by wet-oxidation process, and finally removed SiC oxide layers. A TiW thin film as a metalization process was deposited on the surface treated poly 3C-SiC layer and was annealed through a RTA(rapid thermal annealing) process. TiW/poly 3C-SiC was investigated to get mechanical, physical, and electrical characteristics using SEM, XRD, XPS, AFM, optical microscope, I-V characteristic, and four-point probe, respectively. Contact resistivity of the surface treated 3C-SiC was measured as the lowest $1.2{\times}10^{-5}{\Omega}cm^2$ at $900^{\circ}C$ for 45 sec. Therefore, the surface treatments of poly 3C-SiC are necessary to get better contact resistance for extreme environment MEMS applications.

• 한국분말재료학회지
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• 제21권6호
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• pp.415-421
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• 2014

W-10vol.%ZrC composites reinforced by micrometric and nanosized ZrC particles were prepared by hot-pressing of 25 MPa for 2 h at $1900^{\circ}C$. The effect of ZrC particle size on microstructure and mechanical properties at room temperature and elevated temperatures was investigated by X-ray diffraction analysis, scanning electron microscope and transmission electron microscope observations and the flexural strength test of the W-ZrC composite. Microstructural analysis of the W-ZrC composite revealed that nanosized ZrC particles were homogeneously dispersed in the W matrix inhibiting W grain growth compared to W specimen with micrometric ZrC particle. As a result, its flexural strength was significantly improved. The flexural strength at room temperature for W-ZrC composite using nanosized ZrC particle being 740 MPa increased by around 2 times than that of specimen using micrometric ZrC particle which was 377 MPa. The maximum strength of 935 MPa was tested at $1200^{\circ}C$ on the W composite specimen containing nanosized ZrC particle.