• Title/Summary/Keyword: X-ray diffractometry

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Degree of Gelatinization During Cooking of Rice by X-ray Diffractometry (X-ray 회절법에 의한 쌀의 취반시 호화도 측정)

  • Kim, Sung-Kon;Park, Hong-Hyun;Chung, Hye-Min;Kim, Kwan
    • Applied Biological Chemistry
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    • v.26 no.4
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    • pp.266-268
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    • 1983
  • Dergree of gelatinization during cooking of Akibare(Janponica) and Milyang 23(Indica) rice was determined by X-ray diffractometry using a buit-in internal standard approach. The metod had a total coefficient of Variation of 99.9%. Milyang 23 showed slightly higher degree of gelatinization than Akibare during cooking at $100^{\circ}C$. Both rice was completely gelatinized after 20 minute cooking.

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Pharmaceutical studies on the polymorphism of hydrochlorothiazide

  • Kim, Bong-Hee;Kim, Johng-Kap
    • Archives of Pharmacal Research
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    • v.7 no.1
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    • pp.47-52
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    • 1984
  • 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.

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Crystallization of $K_2O-SiO_2-TiO_2$ Glasses ($K_2O-SiO_2-TiO_2$ 계 유리의 결정화)

  • 김성식;박현수
    • Journal of the Korean Ceramic Society
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    • v.22 no.2
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    • pp.44-50
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    • 1985
  • The crystallization behavior of $K_2O-SiO_2$ glasses with added $TiO_2$ and the effect of $TiO_2$ on internal nuleation at temperature in the range of 875 to 121$0^{\circ}C$ have been investigated by means of X-ray diffractometry optical microscopy and scanning electron microscopy. The crystalline phase of these glasses identified by X-ray diffractometry is cristbalite. The scanning electron microspcopy reveals a two-phase layer of dendritic crystals and intersitial melt which grow from the surface at a constant rate, The observed crystallization rates are consistent with a diffusion-controlled mechanism. An equation relating viscosity and undercooling to growth rate is presented.

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Dissolution Enhancement of Fenticonazole Nitrate from Hydrophilic Polymer Solid Dispersions (친수성 고분자와의 고체분산체로부터 질산펜티코나졸의 용출 증가)

  • Kim, Young-Il;Kim, Seung-In;Choi, Jae-Yoon
    • Journal of Pharmaceutical Investigation
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    • v.19 no.2
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    • pp.109-116
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    • 1989
  • Solid dispersion of fenticonazole nitrate (FN) with poloxamer 407, polyethylene glycol 6000, povidone (K-90) were prepared by the solvent method. To characterize the state of the drug in solid dispersions, the x-ray diffractometry and differential scanning calorimetry were carried out. The identification of these systems suggested that FN in the poloxamer 407 system remained in crystalline state, and the drug in the PVP system was amorphous. A marked increase in the dissolution rate of FN was attained by dispersing the drug in the hydrophilic polymers used, and the dispersion with poloxamer 407 was superior to the other two carriers in releasing the drug into solution.

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A study on the crystallinity of AlN single crystals by heat treatment (열처리에 따른 AlN 단결정의 결정성에 관한 연구)

  • Kang, Seung-Min
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.27 no.3
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    • pp.105-109
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    • 2017
  • AlN single crystal was thermally treated at $1200^{\circ}C$ and $1500^{\circ}C$ in the ambient gas of nitrogen. AlN single crystal was obtained by sublimation growth process using by a facility having a growth part which was heated by RF (Radio Frequency) induction heating. In this report, the optical microscopic results taken from thermally treated AlN single crystal and FWHM (Full width of half maximum) measured by DCXRD (Double crystal X-ray Diffractometry) were reported.

Solubilization and Dissolution Enhancement of Benzimidazole Antnelmintic Drugs by Cyclodextrin Complexation (시클로덱스트린류와의 복합체 형성에 의한 벤즈이미다졸계 구충 약물의 용해성 및 용출 증가)

  • 전인구;박인숙
    • YAKHAK HOEJI
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    • v.37 no.3
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    • pp.216-227
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    • 1993
  • 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 $\gamma$-cyclodextrins(CyDs) in duffered solutions were investigated by solubility method. $A_{L}$ type phase solubility diagrams were obtained in all cases except for the complexation (B$_{s}$, type) of FBZ with $\gamma$-CyD. The highest stability constants were obtained with DM-$\beta$-CyD, followed by $\alpha$-CyD > $\beta$-CyD > HP-$\beta$-CyD > $\gamma$-CyD for ABZ, and HP-$\beta$-CyD > $\gamma$-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-$\beta$-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 (23.9 $\mu\textrm{g}$/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.

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A Study on Iron Compounds of Scoria in The Northern Area of Jeju (제주 북부지역 스코리아의 철 화합물에 관한 연구)

  • Choi, Won-Jun;Ko, Jeong-Dae
    • Journal of the Korean Magnetics Society
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    • v.18 no.5
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    • pp.168-173
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    • 2008
  • Fe compounds of scoria distributed in northern area of Jeju island are investigated using X-ray fluorescence spectroscopy, X-ray diffractometry, and $^{57}Fe$ Mossbauer spectroscopy. The samples were prepared from four parasite volcanos. These samples consist of the typical basalt comprised of $SiO_2,\;Al_2O_3$, Fe compounds, and silicate minerals. The $M{\ddot{o}}ssbauer$ 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.

Effects of Crystal Forms on Dissolution of Cephradin (세프라딘의 용출에 미치는 결정형의 영향)

  • Sohn, Young-Taek;Kim, Ji-Seon
    • Journal of Pharmaceutical Investigation
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    • v.28 no.2
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    • pp.115-119
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    • 1998
  • Five polymorphic modifications of Cephradin were prepared by recrystallization from organic solvents. The isolated crystal forms were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X-ray crystallography powder diffractometry. Modificaition 1 was the most stable form and decomposed at $201.3^{\circ}C$. Modification 3 and 4 were metastable. The dissolution of modification 3 and 4 was faster than that of marketed form.

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Quantitative Analysis of Metallographic Characteristics with Austenitizing Temperature in STD 11 Steel (STD 11 강의 오스테나이트화 온도에 따른 제 특성의 정량 분석)

  • Kim, J.E.;Ju, Y.H.;Jang, W.Y.
    • Journal of the Korean Society for Heat Treatment
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    • v.30 no.5
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    • pp.215-221
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    • 2017
  • 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 $300^{\circ}C$.