碳泡沫衬底上氮化铝纳米线的生长及其光致发光特性研究

为了简化了AlN/C复合泡沫材料的制备流程, 本文采用复分解反应法制备AlN纳米材料, 并通过800℃退火处理使其在碳泡沫衬底上重结晶为六方相AlN纳米线. 通过形貌表征测试, 纳米线为表面光滑的长直形圆柱体, 直径约50 nm, 长度10 μm以上, 在碳微球表面沿[001]方向生长. 同时, 采用VLS生长机理对纳米线的生长进行了解释. 对样品光致发光谱的研究表明, 中心波长423 nm处存在一尖锐发光峰且随温度升高发生明显的红移现象, 系C替N杂质能级跃迁发光所致. 样品在紫光波段具有良好的光致发光特性, 有望应用于光探测器领域.     

空心微球/网络复合型碳泡沫材料制备与机理分析

在Klett等人于2000年制备的韧带网络型碳泡沫和Bruneten等人在2002年制备了一种空心微球碳泡沫材料结构的基础上,分别经过微观结构优化、碳化、石墨化处理,制备出了一种空心微球/网络复合型碳泡沫材料.扫描电镜和体视显微镜测试结果显示网络韧带和球形空腔呈现明显的空间周期性.X射线衍射(X-ray diffraction,XRD)图谱中,26°处的衍射峰表明该试样具有较高的石墨化特征.同时,对该材料的形成机理进行了分析. 关键词： 碳泡沫 微观结构优化 扫描电镜 X射线衍射     

碳硅共掺杂p型AlN的光电性能研究

在SiC衬底上生长了碳硅共掺杂p型AlN晶体,通过X射线衍射、X射线光电子能谱(XPS)、光致发光(PL)光谱、霍尔测试对碳硅共掺杂p型AlN晶体的结构、光学及电学性能进行了综合研究。通过XPS测试分析(尤其是对样品中Si 2p和C 1s的XPS谱分析)发现,样品中C替代N成为受主,而Si替代Al成为施主。样品的PL谱主要包括两个特征发射峰,分别来自于C、Si在AlN中形成的复合物V N-C N和C N-Si Al。     

多壁碳纳米管束储氢机理的X射线吸收谱研究

采用X射线吸收精细结构光谱探索性地研究了多壁碳纳米管束.在多壁碳纳米管束不同入射角的X射线吸收精细结构光谱中，观察到C—H σ^*共振峰强度随入射角的变化而发生变化.在常温常压下出现C—H键可能与多壁碳纳米管束中存在缺陷有关，缺陷数量越大C—H σ^*共振峰的强度越大.光谱中C—C π^*和C—C σ^*共振峰强度的变化趋势都不同于C—H σ^*共振峰，这有力地证明了在常温常压条件下氢原子是吸附在多壁碳纳米 关键词： X射线吸收精细结构光谱 碳纳米管 储氢 化学吸附     

纯六方相氮化铝泡沫材料的合成

在15 mL的不锈钢反应釜中,利用无水三氯化铝与叠氮化钠在无溶剂的条件下直接反应,合成出了六方结构氮化铝泡沫材料,反应温度650 ℃,反应时间3 h.扫描电子显微镜测试结果显示,该试样呈现泡沫状外貌特征.X射线衍射结果表明该试样为六方结构.不同温度条件下的吸收谱表明在202 nm附近存在尖锐的吸收峰.红外吸收谱中存在1381 cm^-1和730 cm^-1两个吸收峰.同时,提出了六方结构氮化铝泡沫材料的合成机理. 关键词： 六方氮化铝泡沫材料 合成机理 X射线衍射     

紫外光辐照镍系聚丁二烯的NMR研究

用¹H NMR谱,¹³C NMR谱,二维谱,X-射线衍射等方法研究了镍系高顺式聚丁二烯橡胶(NiBR) 在强紫外（UV）光辐照前后的微观结构变化和分子运动情况. 分析表明NiBR样品随着UV光辐照时间的增加,侧链乙烯基端基双键比主链端基双键更易发生氧化反应;并且随着NiBR样品的各基团的半峰宽值逐渐增加,表明NiBR在UV辐照过程中发生了部分交联反应. 样品的X-射线衍射谱图中结晶峰强度随UV光辐照时间的增加逐渐降低,表明样品的晶形无序程度增加了. 自旋-晶格弛豫时间（T₁）和自旋-自旋弛豫时间（T₂）值给出了有关NiBR辐照前后分子运动变化的信息.      

波长色散X射线荧光光谱法测定海带中的碘

采用波长色散X-射线荧光光谱法测定了海带样品中的碘含量,通过加标回收实验和精密度实验,证明该方法具有简便快速,不需要繁琐的样品消解和测定过程,可用于实际样品测定.     

Fe_3O_4@SiO_2@CdTe磁性荧光复合微球的制备与表征

采用水热合成法和Stber法制备了氨基功能化SiO2包覆的Fe3O4磁性纳米微球Fe3O4@SiO2-NH2,它与巯基乙酸修饰的CdTe量子点通过酰胺缩合反应,将量子点键合到磁性微球上,制备出单分散性的Fe3O4@SiO2@CdTe磁性荧光双功能微球.用透射电子显微镜、X-射线衍射仪、荧光分光光度计、振动样品磁强计表征了该纳米复合微球的结构和性能.结果表明:Fe3O4@SiO2@CdTe磁性荧光复合微球单分散性好,平均粒径为470nm,饱和磁化强度为37.9emu/g,具有良好的超顺磁性和较高的荧光发光效率.     

用同步辐射X射线衍射技术分析GaN/Si外延膜的结构与应变

选用有AlN和AlGaN缓冲层的GaN/Si作为测试样品,采用同步辐射X射线衍射(SRXRD)技术对样品外延膜(GaN)的几何结构、晶格常量及其应变进行了分析.结果表明,同步辐射X射线衍射实验可以作为一种有效的技术手段,测试固体结构及应变.     

多孔碳纳米球的制备及其电化学性能

以三嵌段共聚物F108为软模板,通过水热法合成酚醛树脂球并在氮气氛围下碳化、KOH活化处理,最终得到多孔碳纳米球材料.通过扫描电子显微镜、透射电子显微镜和氮气吸附分析仪对样品进行表征,结果表明样品的平均粒径为120 nm,球形度高,比表面积达到1403 m~2/g,孔径分布广.通过X射线衍射研究样品的结晶度,傅里叶红外光谱分析样品表面官能团的情况,结果表明KOH处理和高温处理使得样品的微晶结构有序度提高,表面官能团含量降低.以多孔碳纳米球作为超级电容器电极的活性物质,电化学特性测试结果表明,多孔碳纳米球材料的比电容能够达到132 F/g(0.2 A/g),在10 A/g的电流密度下,经过10000次循环充放电后,电容量保留率为97.5%.本文采用水热法制备的多孔碳纳米球电化学性能良好,适用于超级电容器电极材料,研究结果表明,比表面积大、孔径分布合适(具有一定介孔含量)、结晶度高和含有少量表面官能团的理化特性的电极材料,其电化学性能更加优越.     

利用TEM对Si基片与MgO基片上生长的薄膜特性的研究

对生长在Si和MgO单晶基片上的不同厚度的单层NbN薄膜、双层薄膜AlN/NbN以及三层薄膜NbN/AlN/NbN应用透射电子显微镜(Transmission Electron Microscope,TEM)技术进行了分析研究,对这几种薄膜样品的微观结构、薄膜厚度以及各个边界的一些直观细节给出了较为清晰的图像。由透射电子显微镜的电子衍射图案计算了薄膜和单晶衬底的晶格常数,并与我们以前采用X射线衍射技术分析的结果进行了比较,结果有很好的吻合。     

Preparation and Characterization of Polyacrylonitrile and Polyacrylonitrile/β-cyclodextrins Microspheres

Polyacrylonitrile (PAN) and PAN/β-cyclodextrin (β-CD) microspheres were prepared via an electrospinning method. The PAN microspheres could be successfully obtained in a suitable range of concentrations of electrospun PAN solutions. When β-CD was added to the PAN solutions, electrospun PAN/β-CD composite spheres were prepared. The morphology of the spheres was characterized by scanning electron microscopy (SEM); it showed that the spheres had uniform diameter and a smooth surface. The composition of the composite microspheres was studied by Fourier transform infrared spectroscopy (FTIR). The results showed that the β-CD was incorporated in the polymer microspheres.     

Comparison of catalytic activities for photocatalytic and sonocatalytic degradation of methylene blue in present of anatase TiO2-CNT catalysts

Anatase TiO(2)-CNT catalysts with high specific surface areas were prepared by depositing TiO(2) particles on the surface of carbon nanotubes (CNTs) using a modified sol-gel technique. These catalysts prepared with different amounts of CNTs were characterized by nitrogen adsorption, Fourier Transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD), Raman spectroscopy, energy dispersive X-ray (EDX) and ultraviolet-visible (UV-Vis) spectroscopy. The catalytic activity of the anatase TiO(2)-CNT catalysts was assessed by examining the degradation of methylene blue (MB) from model aqueous solutions as a probe reaction under visible light and ultrasonic irradiation. The synergistic effect of the greater surface area and catalytic activities of the composite catalysts was examined in terms of the strong adsorption ability and interphase interaction by comparing the different amounts and roles of CNTs in the catalysts.     

Effect of substrate texture on the growth of hematite nanowires

The effect of texture of iron foil substrate on the growth of hematite nanowires by annealing method has been investigated in detail. Three substrates of different textures were prepared from a [2 0 0] oriented iron foil by some simple processes. The hematite nanowires on these substrates were synthesized by annealing iron foil at 700 °C in moist oxygen. The growth pattern of nanowires on these substrates showed that the growth of hematite nanowires depends strongly on the iron substrate texture and [1 1 0] oriented iron grains are necessary for their growth. The samples were characterized by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD), Electron Back Scatter Diffraction (EBSD) and Raman Spectroscopy. We have also tried to explain the various observations on the mechanism of growth. Mainly, the presence of water vapor significantly enhanced the formation of hematite nanowires which resulted in a very dense and aligned growth of nanowires on the substrate areas of favorable texture. Finally, the study proved the substrate texture to be a powerful tool to control growth of nanowires and can be used efficiently for patterning and large scale synthesis of the nanowires.     

Polishing behavior of PS/CeO2 hybrid microspheres with controlled shell thickness on silicon dioxide CMP

Organic-inorganic composite microspheres with PS as a core and CeO₂ nanoparticles as a shell were synthesized by in situ decomposition reaction of Ce(NO₃)₃ on the surfaces of PS microspheres prepared through soap-free emulsion polymerization. The shell thickness of the composite microspheres could be turned by varying the concentration of Ce(NO₃)₃ in the reaction solution. The whole process required neither surface treatment for PS microspheres nor additional surfactant or stabilizer. The as-synthesized PS/CeO₂ composite microsphere samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Oxide chemical mechanical polishing (CMP) performance of the PS/CeO₂ composite abrasives with different shell thickness was characterized by atomic force microscopy (AFM). The results indicated that the as-prepared core-shell structured composite microspheres (220-260 nm in diameter) possessed thin shell (10-30 nm) composed of CeO₂ nanoparticles (particle diameter of 5-10 nm), and the final CeO₂ contents of the composite microspheres ranged from 10 to 50 wt%. A possible mechanism for the formation of PS/CeO₂ composite microspheres was discussed also. The CMP test results confirmed that the novel core-shell structured composite abrasives are useful to improve oxide CMP performance. In addition, there is an obvious effect of shell thickness of the composite abrasives on oxide CMP performance.     

Fe_3O_4@SiO_2@TiO_2复合纳米结构的尺寸与磁性调控

采用共沉淀法和溶剂热法制备了不同尺寸的Fe_3O_4纳米粒子,通过Stber法和溶胶-凝胶法在Fe_3O_4磁核上包覆SiO_2和Ti O2壳层获得不同尺寸的Fe_3O_4@SiO_2@Ti O2复合纳米结构.采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和振动样品磁强计(VSM)等对其结构、形貌和磁性进行了研究.结果表明,大尺寸复合纳米粒子包覆均匀,分散性好,饱和磁化强度较大,有利于TiO_2光催化剂的磁回收与再利用.     

Fe3O4@SiO2@TiO2复合纳米结构的尺寸与磁性调控

采用共沉淀法和溶剂热法制备了不同尺寸的Fe3O4纳米粒子,通过Stöber法和溶胶-凝胶法在Fe3O4磁核上包覆SiO2和TiO2壳层获得不同尺寸的Fe3O4@SiO2@TiO2复合纳米结构．采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和振动样品磁强计(VSM)等对其结构、形貌和磁性进行了研究．结果表明,大尺寸复合纳米粒子包覆均匀,分散性好,饱和磁化强度较大,有利于TiO2光催化剂的磁回收与再利用．     

纳米ZnO颗粒在阳极Al2O3模板中的强光致发光研究

用金属醇盐水解法在阳极Al2O3模板的有序孔洞中生长了纳米量级的ZnO颗粒,并用扫描电子显微镜（SEM）和高分辨电子显微镜（HRTEM）对其形貌进行观察。对纳米ZnO/多孔阳极Al2O3模板组装体的光致发光谱进行测量,将组装体中ZnO颗粒的发光强度与常规方法制备的纳米ZnO颗粒发光强度做了比较,就发光强度提高的原因进行了讨论。     

Polystyrene/multi-wall carbon nanotube composites prepared by suspension polymerization and their electrorheological behavior

Polystyrene and polystyrene/multi-wall carbon nanotube composites, PS/MWNT, with MWNT content up to 1 wt.% were prepared in the form of microspheres through in situ suspension polymerization. The morphology of the fraction of 32–64 μm was examined by SEM and TEM microscopy. On the surface of the spheres the presence of MWNT was not observed. The microspheres intersections showed the structure of aggregates of sintered beads a few micrometers in size with heterogeneous interface. No MWNT material was observed inside the beads; it seemed to be situated in the heterogeneous phase of microspheres. Suspensions of PS/MWNT in silicone oil show electrorheological effect, whose intensity strongly depends on MWNT content in composite microspheres.