Zn1-xAlxO粉末样品的制备及结构表征

采用固相反应法制备了Zn1-xAlxO粉末样品。通过X射线衍射(XRD)和红外光谱(IR)对粉体的结构和光学性能进行了表征。结果表明:随着Al掺杂浓度逐渐加大,样品ZnO(101)衍射峰的峰位向高衍射角方向移动,x=0.024样品的晶粒大小随温度的升高而增大;通过FT-IR发现Al掺杂样品在427.78 cm-1和487.39 cm-1附近出现了Zn-O的吸收带,表现出良好的红外吸收特性。     

Modulated structure of solid iodine during its molecular dissociation under high pressure

The application of pressure to solid iodine forces the molecules in the crystal to approach each other until intermolecular distances become comparable to the bond length of iodine; at this point, the molecules lose their identity and are essentially dissociated. According to room-temperature X-ray diffraction studies, this process involves direct dissociation of iodine molecules at about 21 GPa, whereas spectroscopic observations have identified intermediate molecular phases at pressures ranging from 15 to 30 GPa. Here we present quasi-hydrostatic powder X-ray diffraction measurements that clearly reveal an intermediate phase during the pressure-induced dissociation of solid iodine. We find that, similar to the behaviour seen in uranium, the structure of this intermediate phase is incommensurately modulated, with the nearest interatomic distances continuously distributed over the range 2.86-3.11 A. The shortest of these interatomic distances falls between the bond length of iodine in the molecular crystal (2.75 A) and the nearest interatomic distance in the fully dissociated monatomic crystal (2.89 A), implying that the intermediate phase is a transient state during molecular dissociation. We expect that further measurements at different temperatures will help to elucidate the origin and stability of the incommensurate structure, which might lead to a better understanding of the molecular-level mechanism of the pressure-induced dissociation seen here and in the molecular crystals of hydrogen, oxygen and nitrogen.     

PVC稀土热稳定剂结构分析

采用红外光谱和X -射线衍射分析 ,对硬脂酸稀土热稳定剂进行结构研究 .红外光谱分析结果表明 ,固态硬脂酸稀土盐中硬脂酸根离子与稀土离子之间主要以离子键结合 ,区别于硬脂酸通过形成氢键而以二聚体结构存在 .X -射线衍射分析结果显示 ,硬脂酸稀土热稳定剂具有层状晶体结构 ,晶层由处于中间的稀土离子平面层两侧结合两层并行排列的硬脂酸根全伸展锯齿链所构成 ,且晶层中稀土离子轴倾斜于基面 .     

KTa0.4Nb0.6O3铁电陶瓷固相反应中红外吸收光谱的研究

利用红外吸收光谱分析方法，研究固溶体钽铌酸钾铁电陶瓷原料在预烧阶段中的固相反应，观察ＫＴＮ材料的中心离子与氧离子键的特征吸收峰的生成过程，判断固相反应完成的程度，确定ＫＴＮ陶瓷的预烧温度，与Ｘ射线衍射结构分析和预烧温度对瓷体密度的影响结果比较，发现红外吸收光谱分析方法是确定铁电陶瓷预烧温度的别一种可靠方法。     

ZnCr_(2-x)Fe_xO_4系列化合物的合成及其性质表征

采用固相法合成了尖晶石结构的ZnCr2O4以及铁取代的系列尖晶石结构化合物,利用X线衍射、红外光谱和磁性测量对该系列化合物进行了表征.结果表明:这些化合物属于面心立方,空间群为Fd 3m,晶胞参数a=0.832 4～0.835 6nm,并且晶胞参数随着掺铁量增大而增加.红外光谱中出现了四面体和八面体吸收峰,而且这2种多面体的吸收峰的波数随着铁含量增加逐渐向低波数方向线性移动.系列化合物的磁矩随磁场的增大而增加,其饱和磁化强度与各向异性场随着铁掺入量增加呈现相反的变化.自发磁化强度随晶粒增大而近乎线性减小.各向异性场的测定表明ZnCr2O4属于软磁性化合物.     

掺杂钙钛矿La0.7Ca0.3MnO3的制备及结构研究

使用高温固相反应法制备了具有钙钛矿结构的锰基氧化物La0.7Ca0.3Mn1-xTixO3,利用X射线衍射、红外光谱等实验技术手段研究其结构和性质。发现在进行掺杂的样品中金属钛离子占据了锰离子的位置,并且所制备的一系列样品均为单相结构。     

磷酸锗铝分子筛GeAPO-5的合成与表征

在弱酸性介质和氟离子存在下,以二乙氨基乙醇为模板剂,采用水热法合成了磷酸锗铝分子筛GeAPO-5。并对其结构和性能进行了表征。研究确证了Ge对AlPO_4-5分子筛骨架的同晶取代。     

碳硫硅酸钙型硫酸盐侵蚀测试方法

碳硫硅酸钙和钙矾石有着很相似的晶体结构及形貌,常规测试中容易将二者混淆.在分析二者物相结构的基础上,介绍和评价了电子显微分析和成分分析、X射线衍射分析、红外和拉曼光谱分析、热分析、核磁共振等测试方法在碳硫硅酸钙型硫酸盐侵蚀研究中的应用特点和不足.电子显微分析和成分分析的结合以及单一的热分析能初步判定腐蚀产物中碳硫硅酸钙的存在,X射线衍射分析很难区分二者,红外、拉曼光谱以及核磁共振能确定硅氧八面体的存在,从而证明存在碳硫硅酸钙,因此研究中宜采用多种测试方法.     

BaCe1-x Yx O3-δ质子导体的制备与性能

采用高温固相合成法制备出掺杂Y³⁺的BaCeO₃电解质BaCe_1-xY_xO_3-δ（x=0.10~0.30). XRD谱分析结果表明,样品均为正交钙钛矿结构;氧空位、 缺陷缔合和固深度均对样品的质子电导率与掺杂浓度有一定影响.     

Neutron and X-ray diffraction study of the broken symmetry phase transition in solid deuterium

The solid hydrogen compounds D2, HD and H2 remain quantum molecular solids up to pressures in the 100 GPa range. A remarkable macroscopic consequence is the existence of a pressure-induced broken symmetry phase transition, in which the molecules go from a spherical rotational state to an anisotropic rotational state. Theoretical understanding of the broken symmetry phase structure remains controversial, despite numerous studies. Some open questions concern the existence of long- or short-range orientational order; whether a strong isotopic shift on the transition pressure should be assigned to the nuclear zero-point motion or to quantum localization; and whether the structures are cubic, hexagonal or orthorhombic. Here we present experimental data on the structure of the broken symmetry phase in solid D2, obtained by a combination of neutron and X-ray diffraction up to 60 GPa. Our data are incompatible with orthorhombic structures predicted by recent theoretical works. We find that the broken symmetry phase structure is incommensurate with local orientational order, being similar to that found in metastable cubic para-D2.     

Variations of optic properties of water under action of static magnetic field

Effects of static magnetic field on optic properties of water are investigated by infrared spectroscopy, ultraviolet spectroscopy and X-ray diffraction, respectively. The ultraviolet spectroscopy experiments show the changes of properties of water under action of static magnetic field, in the region of 191 to 400 nm. The infrared experiment shows that the water exposed in a magnetic field had saturation and memory effects. The magnetized effects increased with increasing exposed time, but were weakened with increasing of time when the magnetic field was removed. In the X-ray experiment, the strength of diffraction increased also, after the water was exposed in magnetic field. Meanwhile, the shift of peak and increase of strength of X-ray diffraction of magnetized water added with nanoFe3O4 occurred as compared with that of pure water added with nano Fe3O4. This result suggests that the magnetized wa- ter has certain magnetism. Finally, these phenomena are simply explained by the molecular structure of water and the theory of magnetization of water.     

Ni掺杂ZnO的结构、光学和磁学性质

利用溶胶-凝胶法制备了Zn1-xNixO(x=0.1 %,0.4 %,0.7 %,1.0 %)粉末,研究了样品的结构、光学和磁学性质.X射线衍射表明所有样品都具有纤锌矿结构,没有发现第2相.随着掺杂量的增加c轴晶格常数变小.X射线光电子能谱显示样品中的Ni离子处于+2价态.由紫外可见光吸收谱发现,随着掺杂量的增加能隙逐渐变小,证实了Ni2+对Zn2+的替代.由光致发光谱发现,在390 nm附近出现了由于近带边自由激子复合引起的紫外峰和以467 nm为中心宽带深能级发光带组成的由缺陷引起的较宽的蓝光.磁化强度测量表明,样品具有室温铁磁性,且随着掺杂浓度的增加,饱和磁化强度增加.当掺杂量为1.0 %时饱和磁化强度最大为0.076 μB/Ni.     

钙钛矿La0.7Pb0.3MnO3的结构和磁性研究

采用固相反应烧结法成功制备了单相多晶样品La0．7Pb0.3MnO3，用X射线衍射和超导量子干涉仪及振动样品磁强计对其结构和磁性进行了研究。结果表明，样品呈菱面相晶体结构，空间群为R-3C，居里温度Tc=348K，在居里温度附近，发生铁磁一顺磁转变。此材料呈现出一种典型的团簇玻璃特性，其阻截温度为336K，并且对零场冷却和场冷却曲线给出了合理的解释。室温下，其矫顽力只有40Oe。     

a-Si∶H薄膜的毫微秒脉冲激光退火

本文报道用电子显微镜观察、X-射线衍射和红外吸收谱等方法研究 a-Si:H 薄膜的毫微秒(ns)脉冲激光退火的结果。从红外吸收谱发现了退火后薄膜中H相关振动吸收的增强现象;通过电子显微镜观察到了厚度≥3μm 的薄膜退火后具有多层结构。讨论了 H 在产生以上现象的机理中的作用。     

制备参数对YBaCo_4O_(7+δ)中低温氧储存能力的影响

利用固相反应法和溶胶凝胶法在不同制备参数下制备了载氧体YBaCo_4O_(7+δ)(Y114相),利用XRD检测了样品的物相组成,使用热重分析仪研究了制备参数对Y114相中低温条件下氧储存能力的影响.结果表明:以固相反应法制备的Y114相样品的中低温氧储存能力强于溶胶凝胶法;二次煅烧20 h样品的中低温氧储存能力更强;以固相反应法制备,在1 150℃二次煅烧20 h、炉冷冷却样品的非化学计量氧δ值为0.89;以溶胶凝胶法制备,在1 050℃下二次煅烧20 h、空冷冷却样品的δ值为0.83.     

Influence of microwave treatment on grinding and dissociation characteristics of vanadium titano-magnetite

The effect of microwave treatment on the grinding and dissociation characteristics of vanadium titano-magnetite(VTM) ore were investigated using scanning electron microscopy(SEM), nitrogen absorption measurements, particle size distribution measurements, X-ray diffraction(XRD) analysis, Fourier transform infrared(FT-IR) spectroscopic analysis, and magnetic separation. SEM analysis showed that microfractures appeared in the microwave-treated VTM, which is attributed to the microwaves' selective heating characteristic and the differential expansion between minerals and gangues. Nitrogen absorption showed that the microfractures were more pronounced when the microwave heating time was increased. Particle size distribution analysis showed that microwave treatment could improve the grindability of the VTM, thus increasing the weight percent of the fine-ground product. The increase in grindability was more significant with prolonged heating time. Moreover, the particle size distribution of the fine-ground product changed only slightly after the microwave treatment. XRD analysis showed that the crystallinity of the microwave-treated VTM increased with increasing microwave heating time. The magnetic separation tests revealed that the separation efficiency increased as a result of the intergranular fractures generated by microwave treatment. The Fe grade of the magnetic fraction of microwave-treated VTM was 1.72% higher than that of the raw ore. We concluded that the microwave treatment was beneficial, especially for the mineral processing characteristics.     

Mixed aromatic-aliphatic organic nanoparticles as carriers of unidentified infrared emission features

Unidentified infrared emission bands at wavelengths of 3-20 micrometres are widely observed in a range of environments in our Galaxy and in others. Some features have been identified as the stretching and bending modes of aromatic compounds, and are commonly attributed to polycyclic aromatic hydrocarbon molecules. The central argument supporting this attribution is that single-photon excitation of the molecule can account for the unidentified infrared emission features observed in 'cirrus' clouds in the diffuse interstellar medium. Of the more than 160 molecules identified in the circumstellar and interstellar environments, however, not one is a polycyclic aromatic hydrocarbon molecule. The detections of discrete and broad aliphatic spectral features suggest that the carrier of the unidentified infrared emission features cannot be a pure aromatic compound. Here we report an analysis of archival spectroscopic observations and demonstrate that the data are most consistent with the carriers being amorphous organic solids with a mixed aromatic-aliphatic structure. This structure is similar to that of the organic materials found in meteorites, as would be expected if the Solar System had inherited these organic materials from interstellar sources.     

基于固/气反应的氧化石墨烯水热还原研究

【目的】对氧化石墨烯的水热还原过程进行系统研究。【方法】采用改进的水热装置,以乙醇为还原剂,通过固/气反应成功实现了水热条件下氧化石墨烯的还原,制备得到石墨烯。通过透射电子显微镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、X射线近边吸收谱(XANES)和热重分析(TGA)对石墨烯材料的结构和性质进行了测试,探讨水热条件下乙醇蒸汽对氧化石墨烯的还原效果。【结果】研究结果表明,水热环境下的固/气反应还原能够有效地去除氧化石墨烯上的含氧基团,石墨烯的π网格结构得到很好的恢复。还原后的石墨烯材料比氧化石墨烯具有更为优异的热稳定性。【结论】该方法低成本、高效、环保,可用于石墨烯的大规模制备。     

Sm2Fe17化合物的吸氮反应研究

通过X-射线衍射、差热-热重（DTA-TG）联用仪以及磁测量等手段,研究了Sm2Fe17化合物吸氮后的相结构及居里温度的变化行为.X-射线衍射表明,吸氮后Sm2Fe17化合物的衍射峰向小角度方向偏移,并且出现了α-Fe的衍射峰,这说明吸氮后化合物的晶胞有所膨胀,并且化合物有一定的分解,产生了α-Fe.差热-热重分析表明,在温度为700 K左右时Sm2Fe17化合物的吸氮反应最剧烈,吸氮以后化合物的居里温度TC有显著的提高;而且随着温度的继续升高,在吸氮反应的同时,Sm2Fe17Nx化合物不稳定,部分分解为SmN化合物和α-Fe.实验结果分析表明,该化合物在1 473 K以下时,只存在Th2Zn17型结构,不存在Th2Ni17型结构.     

La_(0.67)Sr_xMnO_(3-δ)的制备及表征

利用固态反应法制得名义组份为La0 .67SrxMnO3-δ(x=0 .33,0 .2 8,0 .2 3,0 .1 8和 0 .1 3)的多晶样品。X射线衍射表明当 0 .1 8≤x≤ 0 .33时样品是单相的钙钛矿型结构 ,这表明A位可以存在较多的空位。红外吸收光谱显示 ,随着A位空位增多 ,MnO6 八面体基团的伸缩振动模 (波数约为 60 0cm- 1 )的红外活性增强 ,同时电声子散射也随之增强。