• 한국세라믹학회지
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• 제41권2호
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• pp.158-164
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• 2004

우리 주변에서 쉽게 구할 수 있는 12가지 나무와 참나무잎, 소나무껍질 등을 나무 부위별로 구분하여 나무재를 만들어 한국적 천연 재유의 특성을 연구ㆍ분석한 결과 나무재의 주성분은 CaO이며 소나무껍질재는 $SiO_2$, 참나무잎재의 주성분은 CaO와 $SiO_2$이다. 아카시아나무재, 미루나무재 및 대추나무재는 다른 나무재에 비해 MgO와 Fe$_2$ $O_3$ 성분이 많이 함유되어 있어 노랑색기를 띤 녹색유약으로 나타났으며 UV에 의한 4분류 중 가장 채도가 높아 맑은 색을 지닌 투명유 제조에 적합하다. 포도나무재, 배나무재 및 참나무재는 재 안에 많이 함유된 Fe$_2$ $O_3$, MgO 및 MnO의 영향을 받아 UV 분석결과 노랑색기를 띤 녹색 현상이 나타났으며 다른 나무재보다 P$_2$ $O_{5}$의 함량이 많아 온화하고 안정된 느낌을 주는 유백현상이 강하게 나타나 유백유 제작에 적합하다. 소나무재, 플라타너스나무재 및 느티나무재는 다른 나무재에 비해 CaO 성분과 P$_2$ $O_{5}$ 성분이 많아 12가지 나무재 중 가장 선명하고 푸른색기가 많은 녹색 현상이 나타나 청자유약제조에 적합하다. 자작나무, 참나무, 밤나무는 소량으로 유약의 색상에 많은 영향을 주는 MnO가 가장 많이 함유되어 있고 아카시아나무재, 미루나무재, 대추나무재 보다는 약하지만 노랑색기를 띤 녹색유 현상이 나타나 이라보 유약 제조에 적합하다.

• 한국환경보건학회지
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• 제22권2호
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• pp.124-129
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• 1996

In order to investigate the deposition chara.cteristics of water-soluble ionic components in dustfall in Kwangju city, dustfall samples were collected by deposit jar for one year from December 1992 to November 1993. The depositjon amount of dustfall and water-soluble ionic components ($SO_4^{2-}, NO_3^-, Cl^-, NH_4^+, Na^+, Ca^{2+}, Mg^{2+}, K^+$) were measured. The total deposition amount of dustfall was 10.0 ton/$km^2$/month and showed seasonal trend of Summer and Spring > Fall and Winter. The total deposition amounts of water-soluble components showed 2.41 ton/$km^2$/month and seasonal trend of Summer > Fall > Spring > Winter. Deposition amount of $SO_4^{2-}$ was 0.99 ton/$km^2$/month which makes up 41% of water-soluble components. The deposition amounts of dustfall and watersoluble components according to the sampling points were approximately similar to each other. From this result, it can be estimated that the deposition amounts of dustfall and water-soluble components in dustfall were more influenced by the seasonal variation than the regional emission characteristics of pollution source. The content of each ionic component to the deposition amount of water-soluble components showed in order of $SO_4^{2-} > Cl^- > NH_4^+ > Na^+ > Ca^{2+} = K^+ > NO_3^- > Mg^{2+}$ respectively.

• 한국세라믹학회지
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• 제41권5호
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• pp.417-424
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• 2004

메톡시폴리에틸렌글리콜모노메타크릴레이트(MPEGMAA)와 메타크릴산(MAA)을 공중합시킨 폴리카복실레이트계 고유동화제(PCA)의 그라프트 사슬인 폴리에틸렌옥사이드(PEO)의 길이가 다를 경우, 보통포틀랜드시멘트(OPC)의 수화 반응에 미치는 영향을 Fourier Transform Infrared Spectroscopy(FT-IR), X-Ray Diffraction(XRD)과 Differential Scanning Calorimetry (DSC)를 이용하여 조사하였다. PCA의 그라프트 사슬의 길이에 따라 초기 재령에서 수화 반응에 미치는 영향은 달라지나, 장기 재령에서는 큰 차이가 없었다. 또한 PCA가 첨가된 경우의 Ca(OH)$_2$의 상대 피크 강도의 비(I[001］/I［101］)는 OPC에 비해 감소하였다.

• Mycobiology
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• 제41권4호
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• pp.210-213
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• 2013

The objectives of this study were to evaluate applicability of food waste compost (FWC) as a substrate for cultivation of Ganoderma lucidum, Lentinula edodes, and Pholiota adipose, and to determine contents of Ca, Mg, Na, and K in fruiting bodies (FB). FB yield per substrate in FWC-free controls was $53{\pm}4g/kg$ for G. lucidum, $270{\pm}90g/kg$ for L. edodes, and $1,430{\pm}355g/kg$ for P. adipose. Substrates supplemented with FWC showed the highest FB production at FWC content of 10% for G. lucidum ($64{\pm}6g/kg$), and 13% for L. edodes ($665{\pm}110g/kg$) and P. adipose ($2,345{\pm}395g/kg$), which were 1.2~2.5 times higher than the values for the controls. P. adipose contained higher amounts of mineral elements than the other species. Ca, Mg, Na, and K content in FB did not show a significant relation to FWC content.

• 천문학회지
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• 제41권4호
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• pp.83-98
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• 2008

In an attempt of clarifying the connection between the photospheric abundance anomalies and the stellar rotation as well as of exploring the nature of "normal A" stars, the abundances of seven elements (C, O, Si, Ca, Ti, Fe, and Ba) and the projected rotational velocity for 46 A-type field stars were determined by applying the spectrum-fitting method to the high-dispersion spectral data obtained with BOES at BOAO. We found that the peculiarities(underabundances of C, O, and Ca; an overabundance of Ba) seen in slow rotators efficiently decrease with an increase of rotation, which almost disappear at $v_esin\;i{\gtrsim}100km\;s^{-1}$. This further suggests that stars with sufficiently large rotational velocity may retain the original composition at the surface without being altered. Considering the subsolar tendency(by several tenths dex below) exhibited by the elemental abundances of such rapidly-rotating (supposedly normal) A stars, we suspect that the gas metallicity may have decreased since our Sun was born, contrary to the common picture of galactic chemical evolution.

• 대한의생명과학회지
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• 제29권1호
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• pp.41-47
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• 2023

Discovery of new substance that can regulate platelet aggregation or suppress aggregation will aid in the prevention and treatment of cardiovascular diseases. Artesunate is a compound from plant roots of Artemisia or Scopolia, and its effects have shown to be promising in areas of anticancer and Alzheimer's disease. However, the role and mechanisms by which artesunate affects the aggregation of platelets, and the formation of a thrombus are currently not understood. This study examined the ways artesunate affects platelets activation and thrombus formation induced by collagen. As a result, cAMP and cGMP production were increased significantly by artesunate relative to the doses, as well as phosphorylated VASP and IP₃R, substrates to cAMP-dependent kinase and cGMP-dependent kinase, in a significant manner. The Ca²⁺ normally mobilized from the dense tubular system was inhibited due to IP₃R, phosphorylation from artesunate, and phosphorylated VASP aided in inhibiting platelet activity via αIIb/β₃ platelet membrane inactivation and inhibiting fibrinogen binding. Finally, artesunate inhibited thrombin-induced thrombus formation. Therefore, we suggest that artesunate has importance with cardiovascular diseases stemming from the abnormal platelets activation and thrombus formation by acting as an effective prophylactic and therapeutic agent.

• 한국토양비료학회지
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• 제4권1호
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• pp.41-48
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• 1971

관비농법(灌肥農法)에 의한 사질계농지(砂質系農地)자원 개발을 목표로 동 농법에 의한 모래재배를 실시하고 본 농법의 생산성(生産性)을 높이기 위한 기초적 문제로써 칼슘 기타 양(陽)"이온"이 이십일(二十日)무의 생육(生育)과 근권환경(根圈環境)에 관련하여 하나의 생산성요인(生産性要因)을 이루고 있는 것으로 보이는 근계(根系)와 매지(媒地)의 상호작용(相互作用)(응립성(凝粒性))에 어떠한 영향(影響)을 미치는가를 실험하였다. 1. 고수준의 칼슘 및 고수준의 양이온(가리, 칼슘, 마그네슘)을 가진 관비(灌肥)는 모래에서 재배한 그 이일(二日)무우의 생육(生育) 특히 지하부(地下部) 생육(生育)을 촉진하고 수량(收量)을 증대하였다. 2. 고수준 칼슘 공급 및 고수준양이온 공급은 근계(根系)에 모래알을 응립(凝粒)케 하는 응립성을 현저히 증대시키고 있다. 3. 고수준칼슘 및 고수준양이온구에서 응립된모래와 세근(細根)의 Ca함량이 타(他)기관 및 재배상(栽培床)에 비하여 증대되고 있어 응립성에 Ca의 관여를 시사한다. 4. 일반적으로 지상부(地上部)의 Ca, Mg, Mn 함량은 지하부(地下部)보다 높으나 N.P.K는 양기관 사이 큰 차이가 없다. 5. 관비농법하 모래재배가 고도의 생산성을 나타내고 특히 고수준 칼슘 및 양이온공급이 생체중(生體重)과 수량(收量)을 증대하고 있는 것은 칼슘이 관여하는 근계(根系)와 매지(媒地)와의 상호작용 즉 응립성에 의하여 조성된 근권환경(根圈環境)에 연유하는 것으로 보았다.

• 시멘트
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• 통권92호
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• pp.41-54
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• 1983

Calcium Silicate의 생성 및 분해에 미치는 $K_2SO_4$와 $MgSO_4$의 영향을 비교 검토하였으며 Calcium Silicate의 생성을 최대로 하는 $SO_3$, MgO와 $K_2O$의 최적비를 반응표면분석기법으로 조사하였다. $K_2SO_4$의 혼합비 증감에 따라 $C_3S$의 생성촉진에 미치는 영향은 없었다. $C_3S$의 조합원료에 $CaSO_4$를 4.0wt$\%$이상 첨가시 $CaSO_4$는 $C_2S$주위에 Sulphate reaction rim을 형성함으로써 $C_2S$와 CaO의 반응을 방해해 $C_3S$의 생성을 억제하였으나 적당량의 MgO가 첨가되면 $CaSO_4$가 4.0wt$/%$이상이라도 $C_3S$의 생성은 억제되지 않았다. $C_3S$의 생성을 최대로 하기 위한 $SO_3$, MgO와 $K_2O$의 최적비를 반응표면분석기법을 이용하여 다음과 같은 결론을 얻었다. 1. $K_2SO_4$는 $K_2O$에 비해 소결에 미치는 영향이 적으므로 크링카에 고용되고 남은 $K_2O$는 전량 $K_2SO_4$로 전환시켜야한다. 2. $SO_3$와 $K_2O$의 최적비율은 1.5이다. 3. $CaSO_4$와 MgO의 최적비율을 유지하기 위해서는 $CaSO_4$중의 wt$\%SO_3$=0.7의 수준으로 Sulphate의 함량을 조절하여야 한다. 4. $SO_3$와 결합하고 남은 $K_2O$가 0wt$\%$인 경우는 $K_2SO_4$=2.3wt$\%$, MgO=1.5wt$\%$일때 $C_3S$의 생성이 최대로 된다. 5. $SO_3$와 결합하고 남은 $K_2O$가 2.0wt$\%$인 경우는 $K_2$$SO_4$=4.5wt$\%$, MgO=3.0wt$\%$일때 $C_3S$의 생성이 최대로 된다.

• 한국자동차공학회논문집
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• 제14권5호
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• pp.73-78
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• 2006

In this paper, creep tests of Mg-Zn-Mn and Mg-Zn-Mn-Ca alloys, which were casted by mold with Mg-3%Zn-1%Mn and Mg-3%Zn-1%Mn-0.2%Ca, were done under the temperature range of 473-573K and the stress range of 23.42-78.00Mpa. The activation energies and the stress exponents were measured to investigate the creep plastic deformation of those alloys, and the rupture lifes of Mg-Zn-Mn alloy were also measured to investigate the fracture behavior. From the results, the activation energy of Mg-Zn-Mn and Mg-Zn-Mn-Ca alloys under the temperature range of 473-493K were measured as 149.87, 145.98KJ/mol, respectively, and the stress exponent were measured as 5.13, 6.06 respectively. Also the activation energies Mg-Zn-Mn and Mg-Zn-Mn-Ca alloys under the temperature range of 553-573K were obtained as 134.41, 129.22KJ/mol, respectively, and tress exponent were obtained as 3.48, 4.63, respectively. Finally stress dependence of rupture life and the activation energy of rupture life of Mg-Zn-Mn under the temperature range of 473-493K was measured as 8.05, 170.0(KJ/mol), respectively, which were a little higher than the results of steady state creep.

• 한국환경보건학회지
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• 제41권2호
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• pp.90-101
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• 2015

Objective: This study was conducted to develop a chemical oxygen demand (COD) regression model using water quality monitoring data (January, 2014) obtained from the Han River auto-monitoring stations. Methods: Surface water quality data at 198 sampling stations along the six major areas were assembled and analyzed to determine the spatial distribution and clustering of monitoring stations based on 18 WQPs and regression modeling using selected parameters. Statistical techniques, including combined genetic algorithm-multiple linear regression (GA-MLR), cluster analysis (CA) and principal component analysis (PCA) were used to build a COD model using water quality data. Results: A best GA-MLR model facilitated computing the WQPs for a 5-descriptor COD model with satisfactory statistical results ($r^2=92.64$,$Q{^2}_{LOO}=91.45$,$Q{^2}_{Ext}=88.17$). This approach includes variable selection of the WQPs in order to find the most important factors affecting water quality. Additionally, ordination techniques like PCA and CA were used to classify monitoring stations. The biplot based on the first two principal components (PCs) of the PCA model identified three distinct groups of stations, but also differs with respect to the correlation with WQPs, which enables better interpretation of the water quality characteristics at particular stations as of January 2014. Conclusion: This data analysis procedure appears to provide an efficient means of modelling water quality by interpreting and defining its most essential variables, such as TOC and BOD. The water parameters selected in a COD model as most important in contributing to environmental health and water pollution can be utilized for the application of water quality management strategies. At present, the river is under threat of anthropogenic disturbances during festival periods, especially at upstream areas.