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采用水解－插层复合法, 以TiOSO 4 ·2H 2 O为TiO 2 的前驱体, 蒙脱石为复合基体, 通过控制蒙脱石悬浊液pH值, 制备了不同的蒙脱石复合结构样品. 采用XRD研究了样品的结构、物相、晶粒大小等属性的变化. 结果表明, 蒙脱石悬浊液的pH值对TiOSO 4 ·2H 2 O水解属性有较大的影响, 从而影响水合氧化钛/蒙脱石的复合结构特性, 当蒙脱石悬浊液pH为0.5时, 电价较低且聚合度较小的聚合钛离子易于进入蒙脱石层间域, 对蒙脱石结构层的分散剥离作用最好; 经700℃热处理的TiO 2 /蒙脱石复合结构样品中, 锐钛矿晶粒尺寸最小达到13.4 nm; 经1100℃热处理后, 复合结构中锐钛矿相对含量达到35%; 与纯纳米TiO 2 样品相比, TiO 2 /蒙脱石复合结构中的TiO 2 具有更高的锐钛矿相向金红石相转变的温度及更小的晶粒尺寸. 蒙脱石结构层对TiO 2 的相转变和晶粒长大都具有明显的阻滞作用.

The molecular vibrational modes of graphene were analyzed theoretically by factor group analysis.The molecular vibrational modes of graphene and the spectral characteristics of each vibrational mode were calculated successfully.The molecular vibrational frequency and mode of graphene were also calculated by first-principles density functional theory based on establishment of the graphene Bravais crystal unit cell.The number of vibrational modes and corresponding vibrational frequency spectral properties calculated were consistent with the results obtained using factor group analysis.The above calculations and systematic comparison between the infrared and Raman spectra of graphene and graphite were used to determine why the infrared active vibrational modes A 2u and E 1u with D 6h point group did not appear on the experimental infrared spectrum of graphene.

A stable hydrosol of graphene was synthesized by oxidation reduction and then a flow assembly of this graphene was used to form a graphene-based membrane by vacuum extraction filtering method. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, particle size analysis, and scanning probe microscopy (SPM) were used to characterize the crystal structure, granularity, and characteristic change of the molecular spectrum of the samples in the reaction. FTIR tests show that the structural layer of graphite during the oxidation process bonds to a large number of functional groups and parts of these stable functional groups remain on the reduced structural layer of graphene. X-ray diffraction results show that the peaks of the graphite oxide shift to lower angles, become broader and the original graphite peak disappears. Suspensions of graphene oxide form condensed matter and graphene flocculating constituent during film deposition. Particle size analysis and SPM tests show that the particle sizes of the graphene oxide sheets that are dispersed in water show a tailing peak and a broad distribution while the graphene sheets show a singlet, narrower distribution, and smaller dimensions. Raman results show that during oxidation and reduction, the D peak and G peak of the samples gradually extend, ID/IG increases gradually and the degree of sample disorder increases. On the basis of the above analyses, the structural characteristics of the samples in the reaction are summarized.

The Nangqen basin is one of the Tertiary pull-apart basins situated in the east of the Qiangtang block. Similar to the adjacent Dengqen basin and Baxoi basin, there occurred a series of potassic volcanic and sub-volcanic rocks, ranging from basic, intermediate to intermediate-acid in lithology. Based on the study of petrology, mineralogy and geochemistry, including REEs, trace elements, isotopic elements and chronology, the authors concluded that the Cenozoic potassic volcanic rocks in the Nangqen basin were formed in the post-collisional intraplate tectonic settings. The relations between the basic, intermediate and intermediate-acid rocks are neither differentiation nor evolution, but instead the geochemical variability is mainly attributable to the different partial melting degrees of the mantle sources formed at depths of 50–80 km. The sources of the potassic rocks are enriched metasomatic mantle that has experienced multiple mixing of components mainly derived from the crust. The recycling model can be described as follows: after they had subducted to the mantle wedge, the crust-derived rocks were metasomatized with the mantle materials. In view of the fact that the ratio of crust-derived rocks increases by the age of volcanism, it can be concluded that the sources of the potassic rocks moved upwards progressively with time. The underplating of small scattered magmas upwelling from the asthenosphere may have induced partial melting of the sources of the volcanic rocks in some pull-apart basins in the Hengduanshan area and the intense tectonic movements of large-scale strike-slip belts provided conduits for the ascending melts.

As precursors exfoliated from graphite oxide gels, graphene oxide thin films are annealed in a temperature range of 100 ℃ to 350 ℃ to obtain a series of reduced graphene oxide samples with different reduction degrees. For the gas sensing experiments, the reduced graphene oxide thin film gas sensing element is prepared by spin coating with Ag-Pd integrated electronic device (Ag-Pd IED). The functional groups, structures, and gas sensing performance of all the samples are investigated by X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, and gas sensing measurement. The results show that the structure of the graphene oxide samples are transformed to the graphitic structure after reduction at different thermal treatment temperatures. When the reduction temperature is lower than 150 ℃, materials exhibit features of graphite oxide. When the reduction temperature reaches about 200 ℃, the samples show characteristics transformed from graphite oxide to reduced graphite oxide gradually. When the temperature is higher than 250 ℃, materials show features of reduced graphite oxide. During the reduction process, the disorder degree increases from 0.85 to 1.59, and then decreases slightly to 1.41 with the rise of temperature. Additionally, the oxygen containing functional groups are removed with the increasing reduction temperature, and these functional groups can be removed at specific temperatures. In the lower temperature stage (100-200 ℃), the first kind of oxygen containing functional group removed is the hydroxyl group (C-OH) and the epoxy group (C-O-C) is the second. In the higher temperature stage (250-350 ℃), the main removed oxygen containing functional groups are the epoxy group (C-O-C) and the carbonyl group (C=O). The materials treated at 150, 200, 350 ℃ exhibit n-type, ambipolar, and p-type behaviors, respectively, while rGO-200 exhibits considerable increase in resistance upon exposure to hydrogen gas. rGO-200 exhibits very small decrease of resistance at room temperature and moderate increase of resistance at elevated temperatures upon exposure to hydrogen gas, while rGO-350 exhibits considerable decrease of resistance at room temperature upon exposure to hydrogen gas. These results indicate that the reduction temperature affects the distribution of density of states (DOS) in the band gap as well as the band gap size. The graphene oxide and the reduced products at low temperature show good sensitivity to hydrogen gas. With the increasing reduction temperature, the sensitivity fades while the response time and recovery time increases. The gas sensor exhibits high sensitivity (88.56%) and short response time (30 s) when exposed to the 10-4 hydrogen gas at room temperature.

Based on CIE 1976 L*a*b* uniform color space, L*, a*, b* of jadeite-jade, emerald and turquoise were considered as independent variable, then color green of Jadeite-Jade could be distinguished from other two gemstones with discriminant analysis. Three gemstones discriminant functions were given by the fisher analysis. But in order to reduce false rate 22.9% from turquoise and 7.4% from emerald, green color of three gemstones were reclassified into 6 species by K-Means cluster analysis, and then 6 new discriminant functions were calculated to examine the validity of cluster analysis, finally the linear discriminant function model with high accuracy rate 98.8% were erected from fisher discriminant analysis.