• 동굴
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• 제78호
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• pp.1-8
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• 2007

The combination of mechano-chemical activation (MCA)and Self-propagating High-temperature Synthesis (SHS) has widened the technical possibilities for both methods. For YBCO systems the investigation showed that a short-term MCA of initial powders before SHS leads to single-phase and ultra-fine products. A new technique for preparation ultra-fine high-temperature superconductors (HTS) of YBCO composition with a grain size d <1m is developed using combination of MCA and SHS. The specific feature of the technique is formation of the $YBa_2Cu_3O_7-$ crystalline lattice directly from an X-ray amorphous state arising as a result of mechanical activation of the original oxide mixture. The technique allows the stage of formation of any intermediate reaction products to be ruled out. X-ray and magnetic studies of ultra-fine high temperature superconductors are carried out. Dimension effects associated with the microstructure peculiarities are revealed. A considerable enhancement of inter-grain critical currents is found to take place in the ultra-fine samples.

• 한국분말재료학회지
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• 제7권3호
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• pp.123-130
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• 2000

The simulated DUPIC fuel provides a convenient way to investigate fuel properties and behaviours such as thermal conductivity, thermal expansion, fission gas release, leaching and so on. Several pellets simulating the composition and microstructure of the DUPIC fuel were fabricated from resintering powder through the OREOX process of the simulated spent fuel pellets, which were prepared from the mixture of stable forms of constituent nuclides. This study describes the powder treatment, OREOX, compaction and sintering to fabricate simulated DUPIC fuel using the simulated spent fuel. The homogeneity of additives in the powder was observed after attrition milling. The microstructure of the simulated spent fuel was in agreement with the previous studies. The densities and the grain size of simulated DUPIC fuel was pellets are higher than those of simulated spent fuel pellets. Small metallic precipitates and oxide precipitates were observed on matrix grain boundaries.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 SMICS 2004 International Symposium on Maritime and Communication Sciences
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• pp.96-99
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• 2004

The combination of mechano-chemical activation and Self-propagating High-temperature Synthesis (SHS) has widened the possibilities for both methods. For YBCO systems the investigation showed that a short-term mechano-chemical activation of initial powders before SHS leads to single-phase and ultra-fine products. A new technique for preparation ultra-fine high-temperature superconductors of YBCO composition with a grain size d ＜1 ${\mu}{\textrm}{m}$ is developed. The specific feature of the technique is formation of the YBa$_2$Cu$_3$O$_{7-{\delta}}$ crystalline lattice directly from an X-ray amorphous state arising as a result of mechanical activation of the original oxide mixture. The technique allows the stage of formation of any intermediate reaction products to be ruled out. X-ray and magnetic studies of ultra-fine high temperature superconductors (HTS) are carried out. Dimension effects associated with the microstructure peculiarities are revealed. A considerable enhancement of inter-grain critical currents is found to take place in the ultra-fine samples.fine samples.

• 천문학회보
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• 제46권1호
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• pp.57.1-57.1
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• 2021

The icy mantles of interstellar grains are developed by the freeze-out of interstellar molecules and atoms onto grain surfaces. The ice molecules become more complex by surface chemistry induced directly by high energy photons or by the thermal energy diffused over heated grain surface. Therefore, the ice composition is an important tracer of physical conditions where the ices form. Ices have been studied via their absorption features against continuum sources, such as young stellar objects or evolved background stars, in infrared wavelengths. The Spitzer IRS was the most sensitive spectrometer for the observations of infrared ice absorption features. We has been developing an automated analysis tool for the Spitzer IRS spectra, especially for the 15 ㎛ CO₂ bending mode. The 15 ㎛ CO₂ absorption feature is very useful for the study of accretion process in star formation since its spectral shape varies with thermal condition of the dust grains. Eventually, this tool will cover the whole range of the Spitzer IRS spectrum (5~20 ㎛).

• Advances in materials Research
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• 제13권2호
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• pp.141-151
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• 2024

The aim of this work was to determine the behavior of alloy elements and compounds formed during solidification in the manufacturing process of the CuAgZrCr alloy under an oxidizing environment. Bulk and surface analysis techniques, such as Scanning Electron Microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), Raman and X-ray diffraction (XRD) were used to characterize the phases obtained in the solidification process. In order to focus the analysis on the on grain boundary interface, partial removal of the matrix phase by acid attack was performed. The compositional differences obtained by SEM-EDX, Raman and XPS on post-manufacturing materials allowed us to conclude that the composition of grain boundaries of the alloy is directly influenced by the oxidizing environment of alloy manufacturing.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.290-290
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• 2017

Rice (Oryza sativa L.) is one of the most consumed staple food crop which is energy source as carbohydrate and also is considered as the important antioxidant sources including various phenolic compounds. According to the increasing demand of healthy life, the concern to antioxidant also is increasing because of its health-promoting effect. Phenolic compounds are one of the plant secondary metabolites class, which shows various benefits to preventing or treating chronic diseases. In this study, we have measured the total phenol content from total 647 rice samples using the Floin-Ciocalteau method, and then were selected 30 rice genetic resources classified with high, middle, and low group on the basis of total phenol content. The average of the total phenol content of each group was high-group ($6892.9{\pm}488.5{\mu}g\;GAE/g$) > middle-group ($1428.1{\pm}76.0{\mu}g\;GAE/g$) > low-group ($97.6{\pm}11.4{\mu}g\;GAE/g$). The selected rice samples were analyzed with LC-MS/MS to find the composition and concentration of individual phenolic in rice grain. High-group and middle-group contained large amounts of protocatechuic acid and (+)-catechin whereas low-group showed limited amount. Among high-group samples, rice samples with black pericarp color (IT 174089, IT 220079, and IT 259958) had high content of peonidin-3-O-glucoside. Further, these black rice samples were special since polydatin, rarely found stilbenoid in rice grain, was detected. Overall, both the sum of phenolic acid and the sum of flavonoid were high-group > middle-group > low-group. Also, each group exhibited different phenolic compositions; high-group consisted of flavonoid more than phenolic acid, middle-group and low-group was comprised of phenolic acid rather than flavonoid, and non-pigmented rice was composed by fully phenolic acid. The total phenol content had positive relationships with the sum of phenolic compound (r = 0.64), the sum of flavonoid (r = 0.74) at the significance level of p < 0.0001. In addition, protocatechuic acid and quercetin showed positive correlation with above phenolic composition parameters; in order, r = 0.98, 0.65 for protocatechuic acid and r = 0.73, 0.78 for quercetin (p < 0.0001). In conclusion, the total phenol content assay showed the possibility of utilization as a phenolic composition indicator in rice grain. Also, this result was suggested study pigment on other material.

• Asian-Australasian Journal of Animal Sciences
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• 제24권11호
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• pp.1547-1551
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• 2011

Bakery waste (BW) is much cheaper than barley (20 to 40% the price of barley). Bakery waste and barley grain have similar chemical composition; they contain 99 and 97% organic matter (OM), 1.1 and 1.8% fat, 18 and 15% neutral detergent fibre (NDF) and 14.0 and 14.5% crude protein (CP), respectively (DM basis). The objectives of this study were to determine the effect of substituting BW for barley grain in high concentrate fattening diets for lambs on nutrient intake, growth and carcass characteristics. Forty Awassi lambs (21.75${\pm}$1 kg) weaned at the age of 65 days were assigned randomly to four experimental fattening diets differing in BW ratio in a completely randomized design. The control diet (CON) contained 20, 60, 11, 7, and 2% (DM basis) wheat straw, barley grain, soybean meal, corn grain, and minerals and vitamin mix, respectively. Bakery waste substituted barley grain by 10, 20 and 30% of the diet DM in the LBW, MBW and HBW diets, respectively. The experiment lasted for 56 days. Dry matter intake (DMI) decreased (p<0.05) in LBW diet compared to the CON diet by approximately 10%. No further reduction in DMI was observed with the higher substitution levels. Metabolizable energy intake for the CON diet (3.6 Mcal/d) was also reduced (p<0.05) compared with LBW, MBW and HBW diets (3.4, 3.4 and 3.3 Mcal/d, respectively). Final body weight for lambs fed the CON diet (34.8 kg) was higher (p<0.05) compared with lambs fed the LBW, MBW and HBW diets (30.6, 32.0 and 31.1 kg, respectively). Growth rate for lambs fed the CON diet (232 g/d) was also higher (p<0.05) compared to lambs fed the LBW, MBW and HBW diets (170, 189, and 167 g/d, respectively). Feed to gain ratio was higher (p<0.05) for lambs fed the LBW, MBW and HBW diets (7.2, 6.6 and 7.3, respectively) compared with lambs that consumed the CON diet (5.7). Body weight gain cost was reduced by approximately 8% by the MBW and HBW diets as compared with the CON diet. Dressing percentage, full gut weight, empty gut weight and liver weights were all unaffected by the BW addition to the diets and averaged 48.9%, 6.8 kg, 2.8 kg and 0.444 kg, respectively. However, fat tail weight was increased (p<0.05) with the higher levels of the BW inclusion. In conclusion, substituting BW for barley grain reduced DMI and growth performance. However, when BW substituted barley grain at the 20 and 30% of the diet DM, body weight gain cost was reduced by approximately 8%.

• 대한원격탐사학회지
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• 제19권2호
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• pp.117-133
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• 2003

이 연구에서는 곰소만 조간대에서 현장 시료채취와 동시에 얻어진 Landsat ETM+ 자료를 이용하여 조간대 환경요인들이 ETM+에 의해 관측된 반사도와 어떤 관계를 가지고 있는 지 밝히고, 광학위성영상을 이용한 조간대 표층퇴적물의 분류의 적용 가능한 기준입도를 제시하고자 하였다. 일반적인 퇴적학적 분류 기준이 되는 4 $\Phi$ 입도를 기준으로 했을 때 입도와 영상의 반사도 간의 상관관계는 매우 낮은 것으로 나타났으나, 2 $\Phi$ 이상의 입자를 기준으로 하였을 때는 상부조간대의 천주변에 작은 입자로 구성된 지역의 자료들을 제외하면 ETM+ 밴드 4번과 0.699의 높은 상관계수를 보인다. 즉, 입도 2 $\Phi$ 곰소만 조간대에서의 광학위성 자료에 의한 표층퇴적물 분류를 위한 기준입도로 사용하는 것이 타당하다. 입도와 함수율은 비교적 높은 음의 상관관계를 보이며 특히 입도 2 $\Phi$ 기준과는 -0.811로서 뚜렷하게 음의 상관관계를 보인다 위성자료의 Factor analysis 결과는 지형요소에 의해 크게 영향을 받는 독일의 조간대와는 다른 특성을 보이며, 이는 곰소만의 경우는 입자가 세립하여 지형보다는 함수율에 더 큰 영향을 받는 것으로 나타났다. 결국 조간대 원격탐사에서는 입도뿐만 아니라 함수율과 지형 등의 환경요소가 함께 고려하여야만 한다.

• 자원환경지질
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• 제18권3호
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• pp.277-288
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• 1985

초기 쥬라기 대동층군(大同層群)의 사암(砂岩)을 대상으로 광물성분분석(鑛物成分分析)과 입도분석(粒度分析)을 퇴적물(堆積物) 공급지(供給地)와 퇴적환경(堆積環境)을 유추하기 위하여 대동층군(大同層群)의 분포지인 문경(聞慶), 대천(大川), 김포(金浦), 연천(漣川) 지성(地城)에 대해 실시하였다. 사암(砂岩)의 광물(鑛物) 및 입도분석(粒度分析)은 문경지역(聞慶地域)을 중점적으로 하여 대천(大川), 김포(金浦), 연천지성(漣川地城)의 일차적 결과를 첨부하였다. 연구지역(硏究地域)의 사암(砂岩)은 59.8~87.2%의 높은 함량의 석영(石英)을 포함하는 특징이 있다. 석영(石英)중 많은 수가 풍성층(風成層)에서 생성되어지는 원마도가 좋은 dust ring을 나타낸다. 장석(長石)은 극히 드물게 함유되어 있다. 허나 대천지성(大川地城)의 사암(砂岩)은 타지역보다 높은수치인 1.8~10.0%를 함유하고 있다. 연구지역(硏究地域)의 사암(砂岩)의 특성으로부터 대동층군(大同層群)의 공급지(供給地)는 석영질사암(石英質砂岩) 내지 규암(硅岩)이었을 가능성이 매우 높다. 사암(砂岩)은 quartz 내지 quartzose arenite 및 wacke로 분류되며 단, 대천(大川)의 사암(砂岩)은 quartzose 내지 lithic arenite 및 wacke로 분류된다. C-M과 sorting-skewness 그림표의 결과는 하천성환경(河川性環境)을, 누적곡선의 양상은 호수성환경(湖水性環境)을 시사하고 있어 퇴적환경(堆積環境)에 관한 타증거가 필요하다.

• 한국지형학회지
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• 제18권4호
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• pp.223-233
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• 2011

본 연구는 함평만의 간석지 해안지형의 분포특징과 그 변화과정이다. 함평만은 하천의 유입이 없는 분지형태와 같은 반폐쇄형 만으로, 외해 만 입구는 좁고, 내해로 가면서 넓어지는 형태이다. 이곳의 퇴적물 공급원은 조류와 연안사면에서 이동된 물질이다. 연구지역의 주요 지형요소는 간석지, 갯골, 조간대사주, 해식애, 해안단구 등이다. 간석지형은 입도조성에 따라 뻘 간석지, 사질혼성 간석지로 분류되었다. 뻘 간석지는 갯벌이 간석지와 연속성을 보이며 완만히 이어지는 해안지역에, 그리고 사질혼성 간석지는 해식애와 해안단구 기저 지역에 발달하였다. 일부 해안 지형에서는 신생대 4기 해수면 변동으로 퇴적된 지층이 확인되었다. 10년간 간석지 입도조성 변화 분석에서 모래는 2%, 실트는 6% 증가하였고, 점토는 9% 감소하였다. 오목형 간석지에는 염생식물이 정착해 있다. 염생식물의 분포 면적 변화는 2001년에 2.4km²에서 2009년에는 9.3km²로 약 4배 확대되었다. 같은 시기 염생식물 분포 지역에서 평균입도는 6.5φ에서 4.5φ로 조립화되는 경향을 보였다.