• 광물과 암석
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• 제36권4호
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• pp.303-312
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• 2023

망가니즈 단괴를 구성하고 있는 금속 원소의 산화상태의 규명은 단괴의 형성기작 및 성인에 대한 이해를 증진시키고 단괴 형성 당시 수계의 산화-환원 전위 등의 고해양 환경에 대한 단서를 제공한다. 본 연구에서는 상용 X선 광전자 분광분석(X-ray photoelectron spectroscopy; XPS)을 활용하여 자연계 망가니즈 단괴를 구성하는 광물의 결합상태와 금속 원소의 산화상태에 대한 정보를 획득하고자 하였다. 이를 위하여 위하여 광물학적 변동의 영향이 효과적으로 기록된 동시베리아해 천해 단괴를 그 연구의 대상으로 삼았다. XPS Mn 2p 스펙트럼 분석 결과, 단괴의 중심부에서 외곽부로 이동함에 따라 망가니즈 산화 상태에 유의미한 변화가 있음을 확인할 수 있었다. 단괴의 중심부는 Mn⁴⁺가 약 67.9%의 비율을 보이는 반면, 단괴의 최외곽부는 환원된 형태의 Mn³⁺+Mn²⁺의 증가로 인해 Mn⁴⁺의 비율이 약 63%로 감소하였다. 이와 같은 단괴 성장에 따른 망가니즈 산화수의 감소는 단괴가 성장함에 따라 토도로카이트에서 버네사이트로 산화망가니즈 광물종이 변화한다는 기존 연구 결과로 설명된다. 또한 O 1s 스펙트럼 분석 결과 단괴 중심부에 비하여 외곽에서 Mn-O-H 결합이 우세하게 나타나는데, 이는 층상형 버네사이트가 우세한 외곽부에서 보다 해수 혹은 공극수로 인한 수화가 효과적으로 일어났음을 시사한다. 본 연구 결과는 망가니즈 단괴의 성장 중 수계의 산화-환원 양상 등 고해양 조건의 변동에 대해 XPS 방법론이 직접적으로 활용될 수 있음을 제시하며, 향후 보다 높은 분해능의 방사광 X선원을 이용한 실험을 통해 보다 세밀한 단위의 망가니즈 산화수 정보의 획득 및 미량 금속원소의 산화 상태 연구가 가능할 것임을 보여준다.

• 한국토양비료학회지
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• 제12권2호
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• pp.83-89
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• 1979

토양의 이화학적 특성(特性)이 불량(不良)한 사질답(砂質畓)을 개량(改良)코저 규회석(珪灰石), Dolomite, 객토(客土), 퇴비등(堆肥等) 개량제를 병용했을때 이들 개량제가 수도수량에 미치는 영향(影響)을 밝히고저 시험한 결과(結果)는 다음과 같다. 1. 토양중의 무기성분(無機成分) 변화는 개량제 시용(施用)에 의(依)하여 석회(石灰), 고토(苦土), 규산함량(珪酸含量)이 증가되었고 pH도 높게 유지(維持)되었다. 2. 식물체 무기성분(無機成分) 함량중(含量中) 석회(石灰) 규산함량(珪酸含量)은 객토(客土) Dolomite 규회석등(珪灰石等)의 개량제 시용(施用)에 의하여 증가되었다. 3. 규회석(珪灰石)과 Dolomite 시용(施用)에 의(依)하여 식물체중 인산함량(燐酸含量)은 관행(慣行)에 비(比)해 전생육기간(全生育期間)을 통(通)하여 감소(減少)되었고 가리함량(加里含量)도 유수형성기(幼穗形成期) 이후(以後)부터 감소(減少)되었다. 4. 가장 증수된 개량제처리는 객토(客土)+Dolomlte+N 증시처리로서 19% 증수되었으며, 규회석(珪灰石)+유기물처리에서도 10% 증수되었다. 이들 증수요인은 등숙율증가에 기인(基因)되었다.

• Journal of Ginseng Research
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• 제24권3호
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• pp.107-112
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• 2000

적변삼 표피조직의 적갈색의 침적물은 강력한 산화제에 의해서만 산화(탈색)되는 chelation power가 매우 큰 화학결합을 형성하고 있었다. CLSM으로 관찰한 결과, 적변삼 조직의바깥쪽으로 두껍게 침적물이 형성되어 있음이 확인되었으며, 조직의 형광강도를 이용하여 두께를 측정한 결과 약 120rm의 침적물이 축적되어 있음이 확인되었다. 또한 Spectrum분석 결과 적변삼 표피의 물질은 건강삼의 표피조직과는 다른 functional group을 포함하는 것으로 확인되었다. 건강삼과 적변삼의 표피조직을 강산과 강염으로 가수분해 하여도 조직에 침적되어 있는 적색의 물질은 용출되지 않았다. 적변삼과 건강삼의 표피조직과 뿌리의 각 부위별 총 페놀성화합물의 함량을 측정한 결과, 건강삼의 표피조직에서 가장 높게 나타났다. 이러한 결과는 페놀성 물질이 적변물질의 원인이 된다는 보고와 차이가 있는 것으로 페놀성 물질은 적변현상 유발의 직접적인 원인물질이 아님이 확인되었다. 따라서 인삼의 적변물질은 인삼뿌리의 유기성분(세포벽 분해산물, 세포내용물, azodicarbonamide 등)과 철이온 복합체로 추론되며, 이물질에 대한 계속적인 추적을 진행하고 있다.

• 한국재료학회지
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• 제7권2호
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• pp.102-106
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• 1997

박막형 접촉연소식을 포함한 마이크로 가스센서에서 membrane은 Si식각시 식각정지용으로서 또 센서 소자를 지지하는 층으로서 응력이 없어야 하며 이는 응력이 membrane파괴의 주 원인으로 작용하기 때문이다. 이에 따라 본 연구에서는 증착조건이 low pressure chemical vapor deposition(LPCVD)법과 sputtering법으로 제작된 $SiN_{x}$과 $SiN_{x}/SiO_{x}/(NON)$막의 응력고 굴절율 변화에 미치는 효과에 대한 실험을 행하였다. LPCVD의 경우 단일막인 $SiN_{x}$의 압축응력 및 굴절율을 나타내었다. Sputtering의 경우 $SiN_{x}$는 공정압력이 1mtorr에서 30torr까지 증가할수록 인가전력밀도가 $2.74W/cm^2$에서 $1.10W/cm^2$으로 감소할수록 응력값은 압축에서 인장으로 전환되었으며 본 실험에서 응력이 가장 낮게 나온 시편의경우 압축응력으로 $1.2{\times}10^{9}dyne/cm^2$가 공정압력 10mtorr, 인가전력밀도 $1.37W/cm^2$에서 얻어졌다. 굴절율은 공정압력이 1motorr에서 30motorr까지 증가할수혹 인가전력밀도가 $2.74W/cm^2$에서 $1.10W/cm^2$으로 감소할수록 감소하여 2.05에서 1.89의 변화를 보였다. LPCVD와 sputtering으로 증착된 막들은 모두 온도가 증가함에 따라 응력이 감소하였으며 온도감소시 소성적인 특성을 나타내었다.

• 한국토양비료학회지
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• 제43권3호
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• pp.322-328
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• 2010

This study was initiated to investigate the physical and chemical properties of the clay mineral illite and its effect on the growth of cherry tomato (Hongjak) as affected by the forms and concentrations of illite using the bed soil in the glass house. The composition of illite was analyzed by SEM(scanning electron microscope). The cherry tomato was cultivated in the bed soil in the glass house at Chungbuk National University for 10 weeks of total duration. The application rates of illite used as particulate and powder forms were standard 1:20 (w/w), two times 1:10 (w/w), four times 1:5 (w/w) of standard application, respectively. The surface of illite used in the study appeared to be hexagonal sheet and it included K and the variety of other elements. The growth lengths of cherry tomato were 11-23% greater in the pots treated than in the untreated pots. Based on the analyses of the major cations, K, Ca, and Mg from the cherry tomato the amounts of K taken in the leaf and stem of the cherry tomato were 8-45% and 3-30% greater than untreated pots, respectively. The amount of Ca in the leaf and stem taken up by the cherry tomato were 6-39% and 11-40% greater than untreated pots, respectively. The amounts of Mg in the leaf and stem taken up by the cherry tomato were 17-62% and 19-54% greater than untreated pots, respectively. Based on the analysis for the amount of cations, such as K, Ca, and Mg taken up by cherry tomato in treated and untreated bed soil, it appears that the illite treatment enhanced the early growth of cherry tomato.

• 한국수정란이식학회지
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• 제27권2호
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• pp.107-111
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• 2012

Miniature pig sperm cryopreservation is continually researched in biotechnology for breed conservation and reproduction. It is important to control the temperature at each stage of cryopreservation and cryoprotectant. It is also necessary to find the optimal cryoprotectant concentration and chemical elements of the extender. Recently, many studies have used various cryoprotectant materials, such as dimethyl sulphoxide (DMSO), ethylene glycol (EG), antifreeze protein (AFP), amides, and glycerol. Glycerol is a commonly used cryoprotectant. However, glycerol has critical cytotoxic properties, including osmotic pressure and it can cause irreversible damage to live cells. Therefore, We focused on membrane fluidity modifications can reduce cell damage from freezing and thawing procedures and evaluated on the positive effects of trehalose to the viability, chromatin integrity, and motility of boar sperm. Miniature pig sperm was separated from semen by washing with modified- Modena B (mMB) extender. After centrifugation, the pellet was diluted with the prepared first extender. This experiment was designed to compare the effects that sperm cryopreservation using two different extenders has on sperm chromatin. The control group used the glycerol only and it was compared with the glycerol and glycerol plus trehalose extender. Sperm viability and motility were evaluated using WST1 assays and computer-assisted semen assays (CASA). Chromatin structure was examined using acridine orange staining. For the motility descriptors, trehalose caused a significant (p<0.01) increase in total motility ($57.80{\pm}4.60%$ in glycerol vs. $75.50{\pm}6.14%$ in glycerol + trehalose) and progressive ($51.20{\pm}5.45%$ in glycerol vs. $70.74{\pm}8.06%$ in glycerol + trehalose). A significant (p<0.05) increase in VAP ($42.70{\pm}5.73{\mu}m/s$ vs. $59.65{\pm}9.47{\mu}m/s$), VSL ($23.06{\pm}3.27{\mu}m/s$ vs. $34.60{\pm}6.58{\mu}m/s$), VCL ($75.36{\pm}11.36{\mu}m/s$ vs. $99.55{\pm}12.91{\mu}m/s$), STR ($54.4{\pm}2.19%$ vs. $58.0{\pm}1.63%$), and LIN ($32.2{\pm}2.05%$ vs. $36.0{\pm}2.45%$) were also detected, respectively. The sperm DNA fragmentation index was 48.8% to glycerol only and 30.6% to glycerol plus trehalose. Trehalose added group showed higher percentages of sperm motility, stability of chromatin structure than glycerol only. In this study, we suggest that trehalose is effective in reducing freezing damage to miniature pig sperm and can reduce chromatin damage during cryopreservation.

• 환경영향평가
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• 제22권2호
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• pp.135-145
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• 2013

The recycling of coal bottom ash generated from coal power plants in Korea has been limited due to heterogenous characteristics of the materials. The most common management option for the ash is disposal in landfills (i.e. ash pond) near ocean. The presence of large coarse and fine materials in the ash has prompted the desire to beneficially use it in an application such as fill materials. Prior to reuse application as fill materials, the potential risks to the environment must be assessed with regard to the impacts. In this study, a total of nine test cells with bottom ash samples collected from pretreated bottom ash piles and coal ash pond in a coal-fired power plant were constructed and operated under the field conditions to evaluate the leachability over a period of 210 days. Leachate samples from the test cells were analyzed for a number of chemical parameters (e.g., pH, salinity, electrical conductance, anions, and metals). The concentrations of chemicals detected in the leachate were compared to appropriate standards (drinking water standard) with dilution attenuation factor, if possible, to assess potential leaching risks to the surrounding area. Based on the leachate analysis, most of the samples showed slightly high pH values for the coal ash contained test cells, and contained several ions such as sodium, potassium, calcium, magnesium, chloride, sulfate, and nitrate in relatively large quantities. Three elements (aluminum, boron, and barium) were commonly detected above their respective detection limits in a number of leachate samples, especially in the early leaching period of time. The results of the test cell study indicate that the pollutants in the leachate from the coal ash test cells were not of a major concern in terms of leaching risk to surface water and groundwater under field conditions as fill materials. However, care must be taken in extending these results to actual applications because the results presented in this study are based on the limited field test settings and time frame. Structural characteristics and analysis for coal bottom ash may be warranted to apply the materials to actual field conditions.

• 펄프종이기술
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• 제47권4호
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• pp.177-186
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• 2015

Until Mandelbrot introduced the concept of fractal geometry and fractal dimension in early 1970s, it has been generally considered that the geometry of nature should be too complex and irregular to describe analytically or mathematically. Here fractal dimension indicates a non-integer number such as 0.5, 1.5, or 2.5 instead of only integers used in the traditional Euclidean geometry, i.e., 0 for point, 1 for line, 2 for area, and 3 for volume. Since his pioneering work on fractal geometry, the geometry of nature has been found fractal. Mandelbrot introduced the concept of fractal geometry. For example, fractal geometry has been found in mountains, coastlines, clouds, lightning, earthquakes, turbulence, trees and plants. Even human organs are found to be fractal. This suggests that the fractal geometry should be the law for Nature rather than the exception. Fractal geometry has a hierarchical structure consisting of the elements having the same shape, but the different sizes from the largest to the smallest. Thus, fractal geometry can be characterized by the similarity and hierarchical structure. A process requires driving energy to proceed. Otherwise, the process would stop. A hierarchical structure is considered ideal to generate such driving force. This explains why natural process or phenomena such as lightning, thunderstorm, earth quakes, and turbulence has fractal geometry. It would not be surprising to find that even the human organs such as the brain, the lung, and the circulatory system have fractal geometry. Until now, a normal frequency distribution (or Gaussian frequency distribution) has been commonly used to describe frequencies of an object. However, a log-normal frequency distribution has been most frequently found in natural phenomena and chemical processes such as corrosion and coagulation. It can be mathematically shown that if an object has a log-normal frequency distribution, it has fractal geometry. In other words, these two go hand in hand. Lastly, applying fractal principles is discussed, focusing on pulp and paper industry. The principles should be applicable to characterizing surface roughness, particle size distributions, and formation. They should be also applicable to wet-end chemistry for ideal mixing, felt and fabric design for papermaking process, dewatering, drying, creping, and post-converting such as laminating, embossing, and printing.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.287.1-287.1
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• 2016

Three-dimensional (3-D) semiconductor nanoarchitectures, including nano- and micro- rods, pyramids, and disks, are emerging as one of the most promising elements for future optoelectronic devices. Since these 3-D semiconductor nanoarchitectures have many interesting unconventional properties, including the use of large light-emitting surface area and semipolar/nonpolar nano- or micro-facets, numerous studies reported on novel device applications of these 3-D nanoarchitectures. In particular, 3-D nanoarchitecture devices can have noticeably different current spreading characteristics compared with conventional thin film devices, due to their elaborate 3-D geometry. Utilizing this feature in a highly controlled manner, color-tunable light-emitting diodes (LEDs) were demonstrated by controlling the spatial distribution of current density over the multifaceted GaN LEDs. Meanwhile, for the fabrication of high brightness, single color emitting LEDs or laser diodes, uniform and high density of electrical current must be injected into the entire active layers of the nanoarchitecture devices. Here, we report on a new device structure to inject uniform and high density of electrical current through the 3-D semiconductor nanoarchitecture LEDs using metal core inside microtube LEDs. In this work, we report the fabrications and characteristics of metal-cored coaxial $GaN/In_xGa_{1-x}N$ microtube LEDs. For the fabrication of metal-cored microtube LEDs, $GaN/In_xGa_{1-x}N/ZnO$ coaxial microtube LED arrays grown on an n-GaN/c-Al2O3 substrate were lifted-off from the substrate by wet chemical etching of sacrificial ZnO microtubes and $SiO_2$ layer. The chemically lifted-off layer of LEDs were then stamped upside down on another supporting substrates. Subsequently, Ti/Au and indium tin oxide were deposited on the inner shells of microtubes, forming n-type electrodes of the metal-cored LEDs. The device characteristics were investigated measuring electroluminescence and current-voltage characteristic curves and analyzed by computational modeling of current spreading characteristics.

• 한국식품위생안전성학회지
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• 제34권6호
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• pp.551-556
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• 2019

세척수에 포함된 무기물질의 함량이 먹는 물의 수질기준을 초과하여, 참외 GAP 인증을 받지 못하는 사례가 최근 들어 종종 발생하고 있다. 이에 농업현장에서는 껍질을 제거하여 먹는 참외의 소비특성을 감안하여 세척수 수질기준의 일부를 완화해 줄 것을 요청하고 있다. 이에, 본 연구에서는 성주 지역에서 2017-2019년 GAP 인증 참외의 세척에 이용되는 지하수 142건의 수질자료를 근거로 무기물질 4종(불소, 비소, 철, 망간)의 인체 위해성을 평가하였다. 연구 결과, 성주 지역 GAP 참외의 세척에 사용되는 지하수를 음용수 수준으로 섭취하는 우리나라 국민의 4종 무기물질에 대한 HQ는 모두 평균 0.10 이하로 안전한 수준이었다. 특히, 심미적 영향물질인 철, 망간의 경우 성주 지역 지하수를 음용수 수준으로 섭취하는 경우 HQ가 평균 0.00. 과다노출군의 경우 0.01나타났는데, 일반 참외를 섭취하는 국민의 HQ(평균 0.01, 과다노출군 0.03)보다 낮은 수준이었다. 따라서, 성주 지역 지하수를 GAP 농산물의 세척에 활용하더라도 철, 망간을 포함한 4종 무기물질이 인체에 미치는 영향은 미미할 것으로 생각된다.