Mossbauer 分光法과 選擇的 抽出方法에 의한 濟州島 土壤에서의 酸化鐵의 特性 究明

宋寬哲,姜東佑,金斗哲,高正大,洪性樂 濟州大學校 基礎科學硏究所 1997 基礎科學硏究 Vol.10 No.1

濟州島의 8개 代表土壤을 對象으로 하여 X-線 螢光分析, X-線 回折 分析, oxalate와 dithionite-citrate를 사용한 選擇的 抽出方法 및 Mossbauer 分光法으로 一次鑛物, ferrihydrite, 結晶質 酸化鐵의 種類, 含量 및 非磁性 Al이온의 置煥程度에 대하여 考察하였다. 1. X-線 螢光 分析에 의한 濟州島 8개 土壤統의 酸化鐵(Fe₂O₃) 含量은 噴石口 토양인 松岳統에서 18.21%로 가장 높았고 논토양인 大靜統에서 8.03%로 가장 낮았다. 2. X-線 回折 分析 結果 8개 土壤統 모두에서 ferrihydrite와 結晶質 goethite의 回折 피크는 나타나지 않았지만, 結晶質 hematite는 松岳統, 舊巖統 및 黑岳統에서 檢出할 수 있었다. 3. 선택적 침출방법으로 측정한 ferrihydrite 含量은 흑색토인 松堂과 吐坪統, 농암갈색의 분석구 토양인 柑山統 및 갈색삼림토인 黑岳統에서 20.9-35.2g/㎏으로 높았고, 논토양인 大靜統에서 0.85g/㎏으로 가장 낮았다. 結晶質 酸化鐵 含量인 Fed-Feo 含量 松岳統에서 28.7g/㎏으로 가장 높았고 黑岳統에서 7.6g/㎏으로 가장 낮았다. 4. 濟州島 8개 土壤統에 함유되어 있는 常磁性 Fe³+ 鑛物들은 化學造成이 거의 같은 ferrihydrite, 超常磁性 goethite, 층형 硅酸鑒粘土鑛物로서 柑山統에서 그 含量이 가장 높았고 松岳統에서 가장 낮은 것으로 분석되었다. 常磁性 Fe²+ 一次鑛物은 柑山統과 黑岳統에서 olivine, illite의 含量이 優勢하였으나 그 외 土壤에서는 小量의 chlorite, augite, biotite, hornblende 등이 含有되어 있는 것으로 분석되었다. 5. 18K에서 측정된 超微細磁氣場값으로 부터 大靜統에서는 미세한 goethite 만이 含有되어 있는 것으로 確認되었고, 그외 7개 土壤에서는 입자 크기가 작은(∼180Å) 結晶質 hematite와 goethite이 것으로 分析되었다. 6. 濟州島 8개 土壤統에 함유되어 있는 酸化鐵의 구조에서 Fe³+와 非磁性 Al³+이 相堂量 部分 置煥되었음을 確認할 수 있었다. Iron oxide compounds in 8 selected Cheju Island soil samples have been analized by X-ray fluorescence spectrometer(XRF), X-ray diffractometry(XRD), selected chemical techniques, and Mossbauer spectroscopy. The result of this analysis by XRF shows that the rate of quantity of Fe₂O₃ in 8 soil samples was from 8.03wt.%(Daejeong paddy soil ) to 18.21wt.%(Songag soils). Songag, Heugag and Gueom soils were detected to have lower peaks of intensity of hematite by XRD. In addition, these soils were not detected to have hematite and goethite peaks. Ferrihydrite, which is a short-range-order mineral commonly present in volcanic ash soil, was not detected by XRD due to low concentration and/or poor cristallinity. Ferrihydrite contents estimated from Feo values were 8.8∼35.2g/㎏ for volcanic ash soils and 0.85g/㎏ for the Daejeong soil. Most of the soil samples represented by the paramagnetic Fe³+ doublet obtained from Mossbauer spectra at room temperature and 18K were considered to arise from the presence of ferrihydrite, superparamagnetic goethite, and silicate minerals. Also the paramagnetic Fe²+ doublets are attributable to primary minerals such as olivine, illite, chlorite, augite, biotite, and hornblende. Goethite and hematite were identified as the dominant crystalline iron oxides in these soils from Mossbauer spectra obtained at room temperature and 18K. All the soil samples exhibited strong superparamagnetic relaxation. Collapse of the Mossbauer magnetic hyperfine splitting at room temperature was due to the small size(∼180Å) of the oxide particles and/or Al-subsituted goethite.

In-X(X=Pb, Sn) 합금의 마르텐사이트변태거동 특성에 관한 연구

한창석 ( Chang Suk Han ),한승오 ( Seung Oh Han ) 한국열처리공학회 2010 熱處理工學會誌 Vol.23 No.5

The phase transformations and the shape memory effect in In-rich Pb alloys and In rich-Sn alloys have been studied by means of X-ray diffractometry supplemented by metallographic observations. The alloys containing 12~15 at.%Pb transform from the α2 (fct) phase to the α1 (fct) phase by way of an intermediate phase (m phase) on cooling. The results of X-ray diffraction show that the metastable intermediate phase is observed both on cooling and heating, and has a face-centered orthorhombic (fco) structure. It is concluded that the α1 →/← α2 transformation is expressed by the α1 →/← m →/← α2 transformation both on usual cooling and heating with the rate more than 8 × 10(-3) K/s. The m →/← a2 transformation takes place with a mechanism involving macroscopic shear and are of diffusionless (martensitic) type. The temperature hysteresis in the two transformations is 10~13 K between the heating and cooling transformations. The alloys containing 0~11 at.%Sn are -phase solid solutions with a face centered tetragonal structure (c/a> 1) at room temperature, the axial ratio increasing continuously with tin content. The In-(11~15) at.%Sn alloys are mixtures of α and β phases, the β phase having a f. c. tetragonal structure (c/a < 1). The alloys containing more than 15 at.%Sn are β-phase solid solutions. The In-(12.9~15.0) at.%Sn alloys show a shape memory effect only when quenched to the temperature of liquid nitrogen, although their effect becomes weak and finally disappears after keeping at room temperature for a long time. The β → α` phase transformation is of the diffusionless (martensitic) type, and takes place between 330 K at 12.9 at.%Sn and 150 K at 14.5 at.%Sn. The hysteresis of transformation temperatures on heating and cooling is considerably large (29~40 K), depending on the composition. Both In-Pb and In-Sn alloys showed distinct the shape memory effects.

Ingredients and cytotoxicity of MTA and 3 kinds of portland cements

Chang, Seok-Woo,Yoo, Hyun-Mi,Park, Dong Sung,Oh, Tae-Seok,Bae, Kwang-Shik 大韓齒科保存學會 2008 Restorative Dentistry & Endodontics Vol.33 No.4

이 연구의 목적은 3 종의 포틀랜드 시멘트 (포틀랜드 시멘트, 백색 포틀랜드 시멘트, 초속경 시멘트)와 white MTA의 성분 및 세포독성을 비교하는 것이다. 성분비교를 위해서 X선 회절기 (XRD), X선 형광분석기 (XRF), 유도결합플라즈마 원자방출분광 분석기 (ICP-AES)를 사용하였으며 , 세포독성비교를 위해서는 우무확산법 (agar diffusion test)을 사용하였다. 분석 결과, white MTA와 백색 포틀랜드 시멘트는 포틀랜드 시멘트나 초속경 시멘트에 비해 적은 양의 마그네슘 (mg),철 (Fe), 아연 (Zn),그리고 망간 (Mn)을 함유하고 있었다. 또한 초속경 시멘트는 다른 시멘트 및 white MTA에 비해 많은 산화 알루미늄 (Al₂O₃)을 함유하고 있었다. MTA와 포틀랜드 시멘트의 주된 성분은 tricalcicium silicate (3CaO · SiO₂), dicalcium silicate (2Ca0 · SiO₂), tricalcium aluminate (3CaO · Al₂O₃), 그리고 tetracalcium aluminoferrite (4CaO · Al₂O₃ · Fe₂O₃)등이었다. 세포독성 실험결과를 Kruskal-Wallis Exact test와 Bonferroni 사후 겁정법을 사용하여 분석한 결과 white MTA와 3 종의 포틀랜드 시멘트 군 사이에서 통계적으로 유의성 있는 차이를 보이지 않았다 (p > 0.05). White MTA와 3종의 포틀랜드 시멘트의 주성분은 유사하였으나 알루미늄 (Al), 마그네슘 (mg),철 (Fe), 아연 (Zn), 그리고 망간 (Mn) 등의 함량에서는 차이를 보였으며 이러한 차이들은 물리적 성질에 영향을 미칠 것으로 보인다. The aim of this study was to compare the compositions and cytotoxicity of white ProRoot MTA (white mineral trioxide aggregate) and 3 kinds of Portland cements. The elements, simple oxides and phase compositions of white MTA (WMTA), gray Portland cement (GPC), white Portland cement (WPC) and fast setting cement (FSC) were measured by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray fluorescence spectrometry (XRF) and X-ray diffractometry (XRD). Agar diffusion test was carried out to evaluate the cytotoxicity of WMTA and 3 kinds of Portland cements. The results showed that WMTA and WPC contained far less magnesium (Mg), iron (Fe), manganese (Mn), and zinc (Zn) than GPC and FSC. FSC contained far more aluminum oxide (Al₂O₃) than WMTA, GPC, and WPC, WMTA, GPC, WPC and FSC were composed of main phases, such as tricalcicium silicate (3CaO · SiO₂), dicalcium silicate (2Ca0 · SiO₂), tricalcium aluminate (3CaO · Al₂O₃), and tetracalcium aluminoferrite (4CaO · Al₂O₃ · Fe₂O₃). The significance of the differences in cellular response between WMTA, GPC, WPC and FSC was statistically analyzed by Kruskal-Wallis Exact test with Bonferroni' s correction. The result showed no statistically significant difference (p > 0.05) . WMTA, GPC, WPC and FSC showed similar compositions. However there were notable differences in the content of minor elements, such as aluminum (Al), magnesium, iron, manganese , and zinc. These differences might influence the physical properties of cements.

제주 북부지역 스코리아의 철 화합물에 관한 연구

최원준(Won Jun Choi),고정대(Jeong Dae Ko) 한국자기학회 2008 韓國磁氣學會誌 Vol.18 No.5

Fe compounds of scoria distributed in northern area of Jeju island are investigated using X-ray fluorescence spectroscopy, X-ray diffractometry, and ??Fe Mossbauer spectroscopy. The samples were prepared from four parasite volcanos. These samples consist of the typical basalt comprised of SiO₂, Al₂O₃, Fe compounds, and silicate minerals. The Mossbauer spectra showed doublets for olivine, pyroxene, and ilmenite as well as sextets for hematite and magnetite. The valence state of Fe is chiefly a 3+ charge state with a little 2+ charge state. It is expected that this results will add to the body of information related to the information mechanism of Jeju island. The geochemistry for these samples is the same results to mid-mountain's samples in Jeju Island.

양이온성 계면활성제로 표면개질된 몬모릴로나이트의 탈수 특성

이승엽 ( Seung Yeop Lee ),김수진 ( Soo Jin Kim ) 한국광물학회 2002 광물과 암석 (J.Miner.Soc.Korea) Vol.15 No.4

The dehydration of hexadecyltrimethylammonium (HDTMA)- exchanged montmorillonite has been studied using X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). The dehydration in HDTMA-montmorillonite seems to influence the swelling behavior of the organo-clay during heating. The basal d(001) spacing vs temperature curve of the HDTMA-montmorillonite has one broad swelling edge with a shoulder on the low-temperature side. We believe that the shoulder at 100℃ for the HDTMA-montmorillonite is due to interlayer swelling induced by the initial rearrangement of surfactants, and the second edge at 200℃ is caused by interlayer swelling resulting from the secondary vertical reorientation of alkyl chains. It seems that the dehydration of organo-clay induces a reorientation of the alkyl chains by transition to more vertical position relative to the silicate sheets. allowing instantly greater d-spacing.

Pharmaceutical studies on the polymorphism of hydrochlorothiazide

Kim, Bong-Hee,Kim, Johng-Kap The Pharmaceutical Society of Korea 1984 Archives of Pharmacal Research Vol.7 No.1

Four polymorphic forms (I, II, III and IV) of hydrochlorothiazide have been characterized on the basis of x-ray diffractometry and differential thermal analysis. Form I was obtained by crystallization from N, N-dimethylformamide and Form II was crystallized from hot methanol. Form III was precipitated from sodium hydroxide aqueous solution by treatment with hydrochloric acid and Form IV was crystallized from 50% methanol. The metastable form I was a most stable form among four polymorphs, which was stable more than ten months at room temperature. The thermodynamic parameters such as heat of solution, enthalpy, entropy, free energy difference and transition temperature were determined by the measurement of intrinsic dissolution rate. The transition temperature and the heat of transition between the metastable Form I an Form II were determined to be $299.15^{\circ}$K and 5.03 Kcal/mole, respectively and free energy difference ($\delta$ F) was 302. 13 cal/mole. Diuretic action of these four polymorphic forms was also evaluated by monitoring the difference in urinary excretion of sodium, potassium and magnesium in rats.

STD 11 강의 오스테나이트화 온도에 따른 제 특성의 정량 분석

김조은,주용후,장우양,Kim, J.E.,Ju, Y.H.,Jang, W.Y. 한국열처리공학회 2017 熱處理工學會誌 Vol.30 No.5

The effect of austenitizing temperature on the degree of carbides re-solutionizing, mean graine size, hardness and the volume fraction of retaind austenite ($V_{\gamma}$) etc., has been studied by means of metallography, X-ray diffractometry and hardness measurement in STD 11 tool steel. As austenitizing temperature increases, the amount of alloying elements which is re-dissolved into matrix increases, resulting in increase of $V_{\gamma}$, due to the chemical stabilization of austenite. The Vickers hardness value decreases with increasing austenitizing temperature, which is attributed to grain size as well the volume fractions of $V_{\gamma}$ and carbides. Theoretical diffraction intensity of (200) ${\alpha}^{\prime}$, (211) ${\alpha}^{\prime}$ (200) ${\gamma}$ and (220) ${\gamma}$ peaks obtained by $CuK_{\alpha}$ chracteristics X-ray (${\lambda}=0.15429nm$) was calculated, and quantitative analysis of $V_{\gamma}$ could be carried out by X-ray diffraction method. The resultant value is well coincided with the value obtained by image analysis method. When the quenched specimen is tempered above $200{\sim}400^{\circ}C$ for 30 min, the transition carbides i.e., MC and $M_2C$ in the size of about 20 nm begin to precipitate at $300^{\circ}C$.

Crystal Forms of SK-3530

Hyun-Ok Song,손영택 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.12

The objective of this work was to investigate the existence of polymorphs of SK-3530 and the transformation of crystal forms. Two crystal forms of SK-3530 have been isolated by recrystallization and characterized by differential scanning calorimetry, powder X-ray diffractometry and thermogravimetric analysis. The differential scanning calorimetry and powder X-ray diffractometry patterns of two crystal forms were different respectively. After storage of 1 month at 0% RH (silica gel, 20oC), 52% RH (saturated solution of Na2Cr2O7.2H2O/20oC) and 95% RH (saturated solution of Na2HPO4/20oC), Form 2 was not transformed to Form 1 and two forms were shown to have a good physical stability at room temperature for 1 month. In the dissolution studies in pH 6.8 buffer at 37 ± 0.5oC, the dissolution rate of Form 2 was significantly higher than that of Form 1 under 30 min.

시클로덱스트린류와의 복합체 형성에 의한 벤즈이미다졸계 구충 약물의 용해성 및 용출 증가

전인구(In Koo Chun),박인숙(In Sook Park) 대한약학회 1993 약학회지 Vol.37 No.3

Complex formations of practically insoluble antelmintic drugs such as mebendazole (MBZ), albendazole (ABZ) and flubendazole (FBZ) with dimethyl-beta-cyclodextrin (DM-beta-CyD) and 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) together with alpha-, beta- and gammar-cyclodextrins (CyDs) in buffered solutions were investigated by solubility method. AL type phase solubility diagrams were obtained in all cases except for the complexation (BS type) of FBZ with gammar-CyD. The highest stability constants were obtained with DM-P-CyD, followed by allpha-CyD > beta-CYD > HP-beta-CyD > gammar-CyD for ABZ, and HP-beta-CyD > gammar-CyD > beta-CyD > alpha-CyD for FBZ at pH 1.2. On the other hand, solid dispersion systems of ABZ and FBZ with beta- and DM-beta-CyDs were prepared by solvent evaporation method and evaluated by dissolution, differential thermal analysis and powder x-ray diffractometry. The dissolution rates of ABZ- and FBZ-DM-P-CyD solid dispersions were much faster than those of drugs alone, corresponding physical mixtures and tablets on market both at pH 1.2 and 6.8. Although dissolution rates of all samples at pH 6.8 were by far lower than those obtained at pH 1.2, as explained by pH-solubility profiles for ABZ and FBZ, the dissolution rates at pH 6.8 of ABZ from beta- and DM-beta-CyD solid dispersions exceeded the respective equilibrium solubility (23.9mcg/ml). Fast dissolution of ABZ from solid dispersions with CyDs was attributed to the reduction of drug crystallinity and particle size which was supported by DTA and powder x-ray diffractometry. Consequently these results suggest that solid dispersion systems with CyDs may provide useful means to markedly enhance the solubility and dissolution of benzimidazole antelmintic drugs.

재활시스템 구동을 위한 수소저장합금의 제조 특성 분석

신미연,권대규,유창호 제어로봇시스템학회 2019 제어로봇시스템학회 각 지부별 자료집 Vol.2019 No.1

In this paper, Zr0.9Ti0.1Cr0.6Fe1.4 and Zr0.9Ti0.1Cr0.7Fe1.3 were selected as Metal-Hydride(MH) alloys for driving the rehabilitative system. The MH alloys were fabricated by Arc-melting and the compositions of its were analyzed by Field Emission Scaning Electron Microscope(FE-SEM), Energy Dispersive X-ray Spectroscopy(EDS), X-Ray Diffractometry(XRD) and Inductively Coupled Plasma(ICP). As a result of the analysis, the alloys were nonuniform in composition although it was prepared as a single phase of hexagonal structure. In the future, the hydrogen storage capacity of the MH alloys will be evaluated by producing P-C-T diagram of each MH alloys. And MH alloys will be used at driving actuation system for confirming its actual performance.