祁连山玉石沟橄榄岩中非生物成因甲烷‒石墨流体包裹体及其形成条件

研究北祁连造山带玉石沟橄榄岩中富甲烷流体包裹体。激光拉曼光谱原位分析结果显示, 这些流体包裹体主要由液态或气态 CH₄+C(石墨)组成, 次要成分为N₂, H₂O, C₂H₆和C₃H₈, 代表还原性的C-H流体形式。根据石墨的拉曼特征谱峰, 利用石墨化碳质拉曼光谱(RSCM)温度计计算石墨形成温度, 结果指示石墨在流体中沉淀的最低温度介于430~590°C之间, 表明CH₄+C是非生物成因的, 并形成于地幔环境。     

Dielectric relaxation and conduction mechanism in Aurivillius ceramic Bi5Ti3FeO15

For this study, we synthesized Aurivillius Bi5Ti3FeO15 ceramic using the generic solid-state reaction route and then performed room-temperature X-ray diffraction to confirm that the compound had a single phase with no impurities. The surface morphology of the prepared sample was observed to contain microstructural grains approximately 0.2–2 μm in size. The dielectric properties of the sample were determ-ined as a function of frequency in a range of approximately 100 Hz to 1 MHz at various temperatures (303 K ≤ T ≤ 773 K). Nyquist plots of the impedance data were found to exhibit a semi-circular arc in the high-temperature region, which is explained by the equivalent electrical circuit (R1C1)(R2QC2), where R1 and R2 represent the resistances associated with the grains and grain boundaries, respectively, C1 and C2 are the re-spective capacitances, and Q is the constant phase element (CPE), which accounts for non-Debye type of behavior. Our results indicate that both the resistance and capacitance of the grain boundaries are more prominent than those of the grains. The alternating current (ac) conductiv-ity data were analyzed based on the Jonscher universal power law, which indicated that the conduction process is dominated by the hopping mechanism. The calculated activation energies of the relaxation and conduction processes were very similar (0.32 to 0.53 eV), from which we conclude that the same type of charge carriers are involved in both processes.     

Effect of Co substitution on the structural,dielectric and optical properties of KBiFe2O5

Cobalt (Co)-modified brownmillerite KBiFe2O5 (KBFO; [KBiFe2(1?x)Co2xO5 (x = 0, 0.05)]) polycrystalline is synthesized following the solid-state reaction route. Rietveld refinement of X-ray diffraction data confirmed the phase purity of KBFO and KBiFe1.9Co0.1O5 (KBFCO). The optical bandgap energy (Eg) of KBFO decreased from 1.59 to 1.51 eV because of Co substitution. The decrease in bandgap can be attributed to the tilting of the Fe–O tetrahedral structure of KBFCO. The observed room-temperature Raman peaks of KBFCO shifted by 3 cm?1 toward a lower wavenumber than that of KBFO. The shift in Raman active modes can be attributed to the change in the bond angles and bond lengths of the Fe–O tetrahedral structure and modification in response to oxygen deficiency in KBFO because of Co doping. Compared with that of KBFO, the frequency-dependent dielectric constant and dielectric loss of KBFCO decrease at room temperature, which is a con-sequence of the reduction in oxygen migration and modification in response to vibrational modes present in the sample.     

Interaction of Co, Mn, Mg and Al with d(GCCCATGGC) and d(CCGGGCCCGG): a spectroscopic study

Spectroscopic study of the interactions of metal ions, Co, Mn, Mg and Al with d(GCCCATGGGC) and d(CCGGGCCCGG) revealed the following. Metal ions Mn, Al and Mg at the lowest concentrations enhanced the t _m of oligomers, whereas Mn and Mg at higher concentrations decreased the t _m . Co enhanced the t _m of oligomers at higher concentrations. The studies have also indicated that Mn at lower concentrations displaced EtBr fluorescence, Mg and Co at moderate concentrations and Al only at higher concentrations. Addition of Co, Mn, Mg and Al altered the bands of the circulars dichroism (CD) spectra of the oligomers in a concentration-dependent manner. The CD spectra of d(GCCCATGGGC) and d(CCGGGCCCGG) indicated B and Z forms of DNA, respectively, in contrast to the A form observed in the crystal structures. Mg and Co at different ionic strength induced Z–B transition in d(CCGGGCCCGG), while Al at higher concentrations induced a Z–A transition. Mn did not induce any transition. This is the first report to show that Al causes structural transitions in sequence-specific oligomers and has strong binding ability with GC-rich euchromatin oligomers. Received 22 December 1997; received after revision 16 March 1998; accepted 16 March 1998     

TiAlN 保护膜的制备及结构研究

用反应磁控溅射方法制备了ＴｉＡｌＮ薄膜,结构分析表明,当Ｔｉ的含量小于０．２５时,ＴｉＡｌＮ薄膜是Ａｌ基氮化物的闪锌矿结构,但晶格常数随Ｔｉ原子含量的增加而增大．Ｘ射线光电子能谱分析表明,ＴｉＡｌＮ薄膜有与ＡｌＮ和ＴｉＮ不同的电子结构特征．     

用椭圆偏振光谱法研究Ga_xIn_(1-x)P的光学性质(Ⅰ)

用变入射角椭圆偏振技术测量了用金属有机气相沉积（ＭＯＣＶＤ）方法在ＧａＡｓ衬底上生长的ＧａｘＩｎ１－ｘＰ以及掺Ｓｉ和掺Ｚｎ样品在可见光区室温下的光学常数．对其结果进行了讨论,给出了带隙Ｅｇ和跃迁Ｅｇ＋Δ０的能量值,Δ０的实验值与计算值符合的很好．     

电弧等离子体成分和温度同时测量的光谱多线解析法及实验装置(英)

根据等离子体物理学和光谱学理论,建立了一种新的电弧等离子体的测试方法─—光谱多线解析法,可对未知配比的混合电弧等离子体的成分、温度甚至压力的空间分布作同时测定。文中阐明了这一方法和相应的实验装置的原理。测定了氩氢混合电弧等离子体中的氩氢含量及对应的温度、压力分布。对实验结果作了误差分析和验证。     

基于短波近红外光谱盐酸氟桂利嗪粉末药品质量比的估算方法

基于短波近红外(SW-NIR)漫反射光谱,提出一种非破坏定量预测盐酸氟桂利嗪粉末药品质量比的新方法.以高效液相色谱法(HPLC)分析值为参考值,将遗传算法(GA)和神经网络相结合,建立盐酸氟桂利嗪粉末药品的光谱特性与质量比间的定量分析模型.应用GA自动构建神经网络拓扑结构,选择最优的网络参数和光谱波段;讨论不同光谱预处理方法对神经网络预报能力的影响,并对测试集样品质量比进行预测.结果表明,一阶导数数据预处理方法为最优预处理建模方法,其测试集的均方根误差RMSE=0.198 7%,相关系数R=0.986 3.     

拉曼光谱和近红外光谱在小麦粉品质定量分析中的应用

应用拉曼光谱分析技术结合最小二乘法,应用近红外光谱技术结合偏最小二乘法,以及现有的小麦粉光谱数据,对小麦粉进行采集光谱信息,选择最优的光谱预处理方法,分别建立了水分、灰分、面筋的定量模型,并验证了模型的可行性.实验分析表明,近红外光谱技术建立的模型比拉曼光谱分析技术建立的模型效果要好.     

Ce1-xLaxO2-δ（x=0.05-0.50）固溶体的合成与性质研究

利用溶胶-凝胶法合成了固溶体Ce1-xLaxO2-δ,通过粉末X射线衍射（XRD）、原子力显微镜（AFM）、Raman谱和交流阻抗谱系统研究了固溶体Ce1-xLaxO2-δ的结构和输运性质.X射线衍射表明,在0.05≤x≤0.50时,形成了单相立方萤石结构固溶体;Raman光谱测试表明,固溶体中氧缺位含量随掺杂量增加而增大;阻抗谱分析表明,低价稀土离子掺杂使固溶体Ce1-xLaxO2-δ的导电率得到很大提高,x=0.10时导电率达到最大值σ700℃=3.84×10^-2S/cm,σ800℃=8.21×10^-2S/cm,导电活化能为Ea=0.73 eV.