• 제목/요약/키워드: X-ray diffractometry

검색결과 307건 처리시간 0.025초

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

  • 김성곤;박홍연;정혜민;김관
    • Applied Biological Chemistry
    • /
    • 제26권4호
    • /
    • pp.266-268
    • /
    • 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.

  • PDF

Pharmaceutical studies on the polymorphism of hydrochlorothiazide

  • Kim, Bong-Hee;Kim, Johng-Kap
    • Archives of Pharmacal Research
    • /
    • 제7권1호
    • /
    • pp.47-52
    • /
    • 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.

  • PDF

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

  • 김성식;박현수
    • 한국세라믹학회지
    • /
    • 제22권2호
    • /
    • pp.44-50
    • /
    • 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.

  • PDF

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

  • 김영일;김승인;최재윤
    • Journal of Pharmaceutical Investigation
    • /
    • 제19권2호
    • /
    • pp.109-116
    • /
    • 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.

  • PDF

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

  • 강승민
    • 한국결정성장학회지
    • /
    • 제27권3호
    • /
    • pp.105-109
    • /
    • 2017
  • 고주파 유도 가열 장치를 이용하여 승화법으로 성장된 AlN 단결정을 질소 분위기 하에서 $1200^{\circ}C$$1500^{\circ}C$에서 열처리하였다. 열처리 후 단결정 시편들의 표면을 광학현미경으로 관찰하였으며, DCXRD(Double crystal X-ray Diffractometry)를 이용하여 FWHM(Full width of half maximum) 값을 측정하여 결정성의 변화를 평가하였다.

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

  • 전인구;박인숙
    • 약학회지
    • /
    • 제37권3호
    • /
    • pp.216-227
    • /
    • 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.

  • PDF

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

  • 최원준;고정대
    • 한국자기학회지
    • /
    • 제18권5호
    • /
    • pp.168-173
    • /
    • 2008
  • 제주도 북부 지역 오름의 주성분인 스코리아에 대한 화학적 조성, 산화철의 원자가 상태와 자기적 성질을 조사하였다. X-선 형 광분석을 통해서 철 함유량은 $14.08{\sim}20.08\;wt%$ 임을 확인하였고, X-선 회절법을 이용하여 분석한 결과, $SiO_2$와 같은 규산염 외에 소량의 철산화물이 확인되었다. $M{\ddot{o}}ssbauer$ 분광법을 통해서 시료들 내부의 광물 중, 철 성분들이 어떤 형태를 이루는지 알아보았다. 측정한 결과 olivine인 규산염과 pyroxene, ilmenite와 같은 상자성 철산화물 및 상온에서 반강자성 및 강자성 물질인 hematite와 magnetite 산화철 광물들이 확인되었다. 그리고 철 화합물의 원자가 상태는 $Fe^{2+}$인 olivine, pyroxene 그리고 ilmenite 와 $Fe^{3+}$인 hematite, magnetite 등을 포함하고 있다. 주성분으로 볼 수 있는 hematite의 총 면적비는 평균 57.88 wt%이었고 스코리아 내에 존재하는 철의 주 원자가 상태는 대부분 $Fe^{3+}$임을 알 수 있었으며, 이 결과는 다른 제주 중산간 지역의 스코리아와 동 일한 지구화학적 특성을 보이고 있음을 알 수 있다.

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

  • 손영택;김지선
    • Journal of Pharmaceutical Investigation
    • /
    • 제28권2호
    • /
    • pp.115-119
    • /
    • 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.

  • PDF

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

  • 김조은;주용후;장우양
    • 열처리공학회지
    • /
    • 제30권5호
    • /
    • pp.215-221
    • /
    • 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 $300^{\circ}C$.