钛铁矿固溶体分解结构和磁性研究

攀西钒钛磁铁矿床中,钛铁矿固溶体分解生成数量各不相同的钛磁铁矿,导致矿物化学成分和磁性变化。本文通过不同矿石钛铁矿和脉石矿物磁性分布研究,预测选矿工艺技术指标,并为制定适应矿石性质的选矿工艺流程提供依据。

Preparation,physicochemical characterization and cyctotoxicity of solid dispersion of paclitaxel and polyvinylpyrrolidone

The objective of this study was to prepare and characterize paclitaxel-polyvinylpyrrolidone （PTX-PVP） solid dispersions with the intention of improving its solubility and dissolution properties. The PTX-PVP solid dispersion systems were prepared by solvent method. The release rate ofpaclitaxel was determined from dissolution studies and the physicochemical properties of solid dispersion were investigated by differential scanning calorimetry （DSC）, powder X-ray diffraction （PXRD） and scanning electron microscopy （SEM）. The cytotoxicities ofpaclitaxel in solid dispersion to the SKOV-3 cells were assayed by a SRB staining method. The results showed that the solubility and dissolution rate of paclitaxel were significantly improved in solid dispersion system compared with that of the pure drug and physical mixture. The results of DSC and PXRD showed that the paclitaxel in solid dispersion was amorphous form. No paclitaxel crystals in the solid dispersions was found during SEM analysis. Cytotoxicity study suggested that the inhibitory rates of PTX-PVP solid dispersion to SKOV-3 cells were higher than that of pure paclitaxel. The solubility and dissolution of paclitaxel were improved by solid dispersion technique. In vitro cytotoxicity of paclitaxel in solid dispersion was higher than that of pure drug.

Enhancing an internal electric field by a solid solution strategy for steering bulk-charge flow and boosting photocatalytic activity of Bi_(24)O_(31)Cl_(x)Br_(10-x)

Constructing bismuth oxyhalide solid solutions with a single homogeneous phase have intrigued the research community;however,a deeper understanding of the intrinsic origin for improved bulk-charge separation is still unclear.Herein,a series of Bi_(24)O_(31)Cl_(x)Br_(10-x) solid solutions with the same structural characteristics were synthesized by crystal structure regulation.Combining density functional theory calculation,Kelvin probe force microscopy,and zeta potential testing results,an enhanced internal electric field(IEF)intensity between[Bi_(24)O_(31)]and[X]layers was achieved by changing halogen types and ratios.This greatly facilitated bulk-charge separation and transfer efficiency,which is significant for the degradation of phenolic organic pollutants.Owing to the enhanced IEF intensity,the charge carrier density of Bi_(24)O_(31)Cl_(4)Br_(6) was 33.1 and 4.7 times stronger than that of Bi_(24)O_(31)Cl_(10) and Bi_(24)O_(31)Br_(10),respectively.Therefore,Bi24O31Cl4Br6 had an optimal photoactivity for the degradation of bisphenol A,which was 6.21 and 2.71 times higher than those of Bi_(24)O_(31)Cl_(10) and Bi_(24)O_(31)Br_(10),respectively.Thus,this study revealed the intrinsic mechanism of the solid solution strategy for photocatalytic performance enhancement with respect to an IEF.

Physicochemical Characterization and Solubility Enhancement Studies of Mebendazole Solid Dispersions in Solvent Mixtures

Abstract： The objective was to obtain solid dispersion to improve the dissolution rate, solubility and oral absorption of MB （mebendazole）, poor water-soluble drugs. The new formulation was characterized by DSC （differential scanning calorimetry）, PXRD （powder X-ray diffraction）, FT-1R （fourier transform infrared spectroscopy） and STEM （scanning transmission electron microscopy） methods. Solid dispersions of MB with polyvinylpyrrolidone K-30 （PVP K30） were prepared by solvent evaporation method. The solubility of MB （original powder） and that of the solid dispersions was measured at 25℃ in ethanol-water. The aqueous solubility of MB was favoured by the presence of the polymer in solvent mixtures. Combination of solid dispersions with co-solvents increased the water solubility of MB in a larger extent that each method separately. Solubility parameter （o） was used to relate to solubility profiles. MB and the solid dispersions show a solubility curve with a single peak at 51 = 30.78 MPav2. Solid state characterizations indicated that the solid dispersion exist an amorphous material entrapped in polymer matrix getting highest improvement in wettability and solubility.

固态相变法制备纳米复合氧化物陶瓷的研究进展

氧化物陶瓷具有较高的机械强度、电绝缘性能、化学稳定性等,是用途最宽、应用最广、产量最大的陶瓷材料,已经应用于航空航天、军事国防、工业生产等领域。然而,氧化物陶瓷的脆性,严重制约了其在尖端领域的更广泛应用。针对这一难题,近几十年来,国内外学者开始探索固态相变法制备精细纳米结构的氧化物复合陶瓷。通过固态相变法构筑纳米复合氧化物陶瓷的纳米/亚微米/微米尺度的结构,以提高纳米复合氧化物陶瓷的力学性能。本文系统综述了固态相变法对纳米复合氧化物陶瓷结构和性能的影响,旨在阐明相关的原理及工艺,为高性能纳米复合氧化物陶瓷的制备提供参考与借鉴。

Fe^(3+)、Fe^(2+)对C_3S晶体稳定性的影响

用分析纯试剂配制了C_3S的含Fe^(3+)或Fe^(2+)的两个系列固溶体样品。电子探针分析表明,Fe^(3+)或Fe^(2+)均优先溶解于C_2S中。固溶体分解实验表明,Fe^(3+)和Fe^(2+)进入C_3S晶格均能明显促进其分解;含Fe^(3+)以及少量Fe^(2+)的C_3S固溶体比含纯粹Fe^(2+)的固溶体更容易分解。并比较Fe^(3+)和Fe^(2+)对C_3S晶体化性能的影响。

The preparation and characteristics of febuxostat SiO2 solid dispersions

In the present research, we selected Sylysia as a porous material and febuxostat（FBT） as model drug to prepare the FBT SiO2 solid dispersions using a solvent evaporation method. We firstly established an HPLC method for determining FBT in our prepared FBT SiO2 solid dispersions. And then, the characteristics of FBT SiO2 solid dispersions were investigated, including differential scanning calorimetry（DSC）, powder X-ray diffraction（PXRD）, scanning electron microscope（SEM）, particle size and distribution. The solubility and dissolution of FBT SiO2 solid dispersion were also evaluated. The results of DSC and PXRD showed that the FBT existed in an amorphous state in FBT SiO2 solid dispersions. The SEM and particle size results indicated that the shape and average particle size of FBT SiO2 solid dispersions was similar to the Sylysia. The solubility and dissolution of FBT in FBT SiO2 solid dispersions were significantly enhanced compared with the pure FBT. In conclusion, we successfully prepared FBT SiO2 solid dispersions to increase the solubility and dissolution rate of the poorly water-soluble FBT.