基于微球透镜的任选区高分辨光学显微成像新方法研究

提出和发展了基于毛细管-微球组合探针的任选区、 高分辨显微成像新方法. 建立了微球显微成像的物理模型, 利用成像理论,推导出微球成像的放大倍率; 采用3.0, 4.4, 5.6, 7.5, 10.0 μm等不同直径的SiO₂微球, 对未经刻录的DVD光盘进行了微球显微成像实验, 可以观察到DVD光盘的微纳米结构被明显放大且对比度显著提高, 与理论计算结果相符合; 采用毛细管微探针操纵微球的方法, 实现了基于微球透镜阵列的样品微纳米结构的高分辨显微成像; 在此基础上, 进一步将毛细管微探针与微球组合, 制备出毛细管-微球组合型探针, 首次实现了基于微球透镜的样品任意区域高分辨显微成像.     

Zno纳米粒子在PS中空微反应器中的合成与光学性能

通过种子乳液聚合合成核壳结构的聚甲基丙烯酸甲酯/聚苯乙烯(PMMA/PS)复合微球,通过酸碱溶胀法进一步制备出次微米级的PS中空微球. 将此中空微球作为微反应器,使在ZnO纳米粒子前驱体溶液中溶胀, 最终ZnO纳米粒子在PS中空微球中原位生成. 实验表明, 组成ZnO纳米粒子前驱体溶液的两种组 分(CH₃COO)₂Zn和LiOH的滴加顺序不同对最终生成的ZnO纳米粒子的尺寸和负载效率有很大的影响,但并不改变ZnO纳米粒子的晶型. 复合物的光致发光和UV-Vis吸     

六方相纤锌矿硫化锌微球的制备及性能研究

以谷胱甘肽(GSH)为硫源,氯化锌(ZnCl2)为锌源,溴化十六烷基三甲铵(CTAB)为表面活性剂,乙二胺为反应媒介,采用水热法在较低温度(160℃)下成功地合成六方相纤锌矿硫化锌(ZnS)纳米微球。采用扫描电子显微镜观察纳米微球的形貌,利用X射线衍射仪分析其物相,借助荧光光谱仪和紫外分光光度计分析不同条件下合成的硫化锌纳米微球的光学性能。实验结果表明,CTAB能够促进空心微球的形成,以CTAB为致孔剂能够在相对较低的温度条件下得到由纳米粒子组成的微米量级的单分散六方相纤锌矿结构的硫化锌微球。通过改变其他反应参数可以得到不同壳厚的硫化锌微球,测试其发光性能发现空心球的荧光效果明显好于实心球。     

外界环境对微球腔品质因数的影响

光学微腔由于其高品质因子(Q)特性具有广泛的应用前景.本文以光学微球腔为例分析了影响Q的各种因素,并通过实验研究分析了光学微球腔所处环境对Q的影响.选用直径约为260 μm的典型微球腔与锥形光纤进行耦合,通过透射谱的变化来反应Q的变化,结果表明,微球腔周围水蒸气的光吸收损耗和粉尘的散射损耗对微球腔的Q影响较大,能够导致...     

壳核型磁性纳米纤维素微球的超声制备及表征

以纳米级的Fe3 O4液体作为磁核 ,在非水体系的纤维素DMAc(N N二甲基乙酰胺 ) /LiCl溶液中 ,使用包埋法 ,在超声波的辅助下制备得到了纳米尺度的壳核型磁性纤维素微球 .利用FT IR、XRD及AFM/MFM (原子力显微镜 /磁场力显微镜 )对得到的磁性微球进行了表征 ,证实该微球由磁性的核与纤维素的壳组成 ,微球大小为 30～ 5 0nm ,且具有良好的分散性 .并研究了超声条件对磁性微球尺寸的影响 .     

拉曼光谱法研究纳米结构多孔ZnO微球的合成机理

利用拉曼光谱方法,对柠檬酸钠辅助水热合成纳米结构多孔ZnO微球的机理进行了研究。样品的拉曼光谱特征显示,多孔ZnO微球中存在Zn-柠檬酸配合物;分析表明反应溶液中柠檬酸钠水解产生的柠檬酸根与Zn2+结合形成Zn-柠檬酸配合物,该配合物化学吸附在Zn(OH)₂晶核的(204)和(503)晶面,使Zn(OH)₂晶核择优生长形成纳米薄片状结构;水热过程中Zn(OH)₂微晶团聚形成纳米片状结构多孔Zn(OH)₂微球并以沉淀析出。研究发现吸附在薄片表面的Zn-柠檬酸配合物提高了Zn(OH)₂微晶的热稳定性,使得Zn(OH)₂的分解温度高于200 ℃,加热到300 ℃后Zn(OH)₂完全分解获得纳米结构多孔ZnO微球。     

空心Fe_3O_4纳米微球的制备及超顺磁性

采用水热控制合成法,以六水三氯化铁、柠檬酸三钠和尿素为原料,聚丙烯酰胺为稳定剂, 200?C下反应12 h制备得到了超顺磁性空心Fe_3O_4纳米微球.通过X射线衍射仪、扫描电子显微镜、透射电子显微镜对样品的结构和形貌进行表征,并采用振动样品磁强计测试了样品的磁性能.结果表明:所得样品为具有尖晶石结构的Fe_3O_4纳米微球,尺寸为160 nm左右,呈分等级结构,即整个微球由粒径约18 nm的初级晶粒自组装堆叠而成;室温下表现为典型的超顺磁性,且饱和磁化强度为73.3 emu/g (1 emu/g=1 A·m~2/kg),这种高饱和磁化强度可以由其初级晶粒晶化程度高且粒径较大以及这种特殊的二次自组装结构进行解释.这种Fe_3O_4纳米微球为疏松多孔的空心球状结构,具有粒径分布均匀、分散性良好和超顺磁性的特点,在药物靶向输运和肿瘤热疗中有潜在的应用.     

含丙磺舒高分子药物纳米微球的制备

非甾体抗炎药丙磺舒与甲基丙烯酸 2 羟乙酯 (HEMA)反应制得含丙磺舒单体HP ,此单体在乙醇 /水体系中与甲基丙烯酸甲酯 (MMA)共聚得到含丙磺舒高分子药物纳米微球 ,聚合产物用1H NMR ,FTIR ,GPC和TEM进行了表征。结果表明HP中丙磺舒以酯键连接到甲基丙烯酸 2 羟乙酯上 ,微球由HP和MMA的共聚物构成 ,平均直径为 ( 90± 5 )nm ,含丙磺舒 4 7 4 % ,含药量较高。     

微模塑法制备PMMA/SiO2二氧化硅杂化材料微结构

以摩尔比为 1∶1的甲基丙烯酸甲酯 (MMA)、甲基丙烯酸 (3 三乙氧基硅烷基 )丙酯 (ESMA)单体、0 .2 %(单体总量的质量分数 )的偶氮二异丁腈AIBN引发剂和四氢呋喃 (THF)溶剂 ,及 2 0 % (总质量分数 )的正硅酸乙酯TEOS合成出PMMA/SiO2 有机 无机杂化的杂化溶胶 .将溶胶在洗净的普通光学玻璃基片表面甩膜 .利用软刻蚀中的微模塑法 ,把有机硅弹性印章复制有精细图纹一面轻放在杂化溶胶膜上进行微模塑 ,外加 1N压力于12 0℃下处理 2h使溶胶凝胶化 .印章剥离后在基片表面就形成了PMMA/SiO2 有机 无机杂化材料的微图纹结构 .从微图纹的光学显微镜照片可以看出微模塑方法制备杂化材料复制的图纹精细度高 ,操作简单易行 ,是一类比较理想的微细图纹结构加工的方法 .     

快速响应恢复的PI-SiO2/NiI2比色湿度传感器

有机-无机杂化型比色湿度传感器可通过电学信号和颜色变化获取环境湿度,并因其特征颜色区分度高、稳定性好、制备工艺简单等优点,在湿度监测领域具有广阔的应用前景,但其通常响应恢复时间长,从而不利于湿度实时监测.本文在聚酰亚胺(PI)-碘化镍(NiI₂)有机无机杂化材料中掺杂纳米SiO₂微球制备得到PI-SiO₂/NiI₂复合薄膜及比色湿度传感器,对其表面形貌和湿敏特性进行了研究.结果显示, PI-SiO₂/NiI₂薄膜具有蜂巢状的表面形貌,传感器的特征颜色显著,湿度响应时间小于1.5 s,恢复时间小于18 s.研究表明,纳米SiO₂微球掺杂能够较为显著地改善有机-无机杂化型比色湿度传感器的响应恢复特性,这对于传感器性能的提升具有一定参考意义.     

Tb(Asprin)_3Phen/SiO_2壳/核型纳米材料的合成和光学性质

利用W/O微乳液方法合成了直径为40 nm的具有类壳/核结构的Tb(Asprin)3Phen/SiO2纳米球.透射电子显微镜(TEM)证实了该纳米球具有尺寸均一,分散性好的特点.另外,通过TEOS与APS在微乳液中同时水解,在材料的表面引入了大量的氨基,为材料的生物应用提供了有利的条件.红外光谱(FT-IR)和光致发光光谱分析也显示了这种材料在生物领域中有着潜在的应用前景.     

SiO_2/Ag核壳结构纳米粒子的制备及其表面荧光增强

以罗丹明B掺杂的SiO2球为核,通过化学还原的方法制备了二氧化硅/银核壳结构复合纳米粒子。采用透射电镜(TEM)、紫外-可见-近红外(UV-Vis-NIR)分光光度计和荧光分光光度计对二氧化硅/银核壳结构纳米粒子的表面形貌、表面等离子共振和表面荧光增强特性进行了研究和表征。结果表明,二氧化硅/银核壳结构纳米粒子的表面等离子共振峰具有明显的可调谐性,且其表面荧光增强强烈依赖于银壳层的表面等离子共振,随银壳层厚度的增大而增强。     

Preparation and photocatalytic properties of hybrid core–shell reusable CoFe2O4–ZnO nanospheres

Magnetically separable and reusable core–shell CoFe₂O₄–ZnO photocatalyst nanospheres were prepared by the hydrothermal synthesis technique using glucose derived carbon nanospheres as the template. The morphology and the phase of core–shell hybrid structure of CoFe₂O₄–ZnO were assessed via TEM, SEM and XRD. The magnetic composite showed high UV photocatalytic activity for the degradation of methylene blue in water. The photocatalytic activity was found to be ZnO shell thickness dependent. Thicker ZnO shells lead to higher rate of photocatalytic activity. Hybrid nanospheres recovered using an external magnetic field demonstrated good repeatability of photocatalytic activity. These results promise the reusability of the hybrid nanospheres for photocatalytic activity.     

Preparation of novel magnetic fluorescent nanospheres by sonochemical method

This study focuses on the preparation and characterization of magnetic fluorescent nanospheres (MFNs). MFNs are prepared using a sonochemical method in the presence of hydrophobic Fe₃O₄ nanopaticles, and then the nanospheres are modified with Rhodamine B through an electrostatic interaction. The properties of MFNs are characterized using transmission electron microscopy, Fourier-transform infrared, thermogravimetric analysis, vibration sample magnetometry, and fluorescence emission spectrum. The results indicate that the superparamagnetic nanospheres have a particle size of 160 nm, high saturation magnetization of 54 emu/g, and significant fluorescence. MFNs possess potential in medical imaging, drug targeting, and catalysis. The possible formation mechanism of MFNs is discussed.     

氧等离子体处理对GaAs表面单层自组装SiO2纳米球薄膜的影响

二维纳米阵列结构因其重要的光学性能被广泛应用于各类光电子器件。本文对自组装单层SiO2纳米球掩模刻蚀法制备GaAs纳米柱二维阵列结构的关键工艺技术进行了研究。采用旋涂法在GaAs表面制备自组装单层SiO2纳米球,重点研究了GaAs表面氧等离子体亲水处理工艺对纳米球排列特性的影响,获得最佳工艺条件为功率配比100 W+80 W、腔室压力4 Pa、氧气流量20 mL/min、处理时间1200 s,并最终得到排列紧密的大面积单层纳米球薄膜。以单层纳米球为掩模,采用感应耦合等离子体刻蚀技术在GaAs表面制备了纳米柱阵列并测试了其表面光反射谱。测试结果表明,GaAs纳米柱阵列在特定波段的反射率降低至5%,远低于表面无纳米结构的薄膜材料表面高达40%的光反射。分析表明纳米柱可以激发米氏散射共振效应,从而有效降低反射率并提升光吸收。     

Graphene-CdS composite, synthesis and enhanced photocatalytic activity

Graphene-CdS (G-CdS) composites were synthesized through a simple solvothermal method. The formed CdS nanospheres were homogeneously scattered on the surface of graphene sheets. Fluorescence quenching effect of the G-CdS composites indicated effective transfer of photo-excited electrons from CdS to graphene, suppressed the recombination of photo-generated electron-hole pairs, so that the enhanced visible light induced photodegradation activity for Rhodamine B (RhB) was achieved. Based on the high photocatalytic activity and well stability, the G-CdS composite containing 70% CdS can be expected to be a practical visible light photocatalyst.     

Only Ku-band microwave absorption by Fe3O4/ferrocenyl-CuPc hybrid nanospheres

A novel kind of hybrid nanospheres made of Fe₃O₄ and ferrocenyl-CuPc (FCP) was prepared via effective solvothermal method and performed microwave absorptivity only in Ku-band with minimum reflection loss of −25 dB at 16.0 GHz corresponding to absorbing about 99.7% content of microwave. Scanning electron microscopy images indicated that the nanospheres with uniform particle size distribution have the average diameter of 135 nm. Due to the synergistic reaction between magnetic ferrocenyl-CuPc and Fe₃O₄, the hybrid nanospheres showed novel electromagnetic properties. The real part of complex permittivity of hybrid nanospheres remains stable in the range of 0.5–12.0 GHz and has a large fluctuation at 16.5 GHz. Moreover, the dielectric loss of hybrid nanospheres also appeared a sharp peak at 16.3 GHz with the value of 2.7. The specific gravity of hybrid nanospheres is about 2.08. On the basis of these results, the novel hybrids are believed to have potential applications in the microwave absorbing area in Ku-band.     

Solvothermal synthesis and characterization of CdSe nanocrystals with controllable phase and morphology

Zinc blende (ZB) CdSe hollow nanospheres were solvothermally synthesized from the reaction of Cd(NO₃)₂·4H₂O with a homogeneously secondary Se source, which was first prepared by dissolving Se powder in the mixture of ethanol and oleic acid at 205 °C. As Se power directly reacted with Cd(NO₃)₂·4H₂O in the above mixed solvents, wurtzite (W) CdSe solid nanoparticles were produced. Time-dependent experiments suggested that the formation of CdSe hollow nanospheres was attributed to an inside-out Ostwald ripening process. The influences of reaction time, temperature and ethanol/oleic acid volume ratio on the morphology, phase and size of the hollow nanospheres were also studied. Infrared (IR) spectroscopy investigations revealed that oleic acid with long alkene chains behaved as a reducing agent to reduce Se powder to Se²⁻ in the synthesis. Photoluminescence (PL) measurements showed that the ZB CdSe hollow nanospheres presented an obvious blue-shifted emission by 42 nm, and the W CdSe solid nanoparticles exhibited a band gap emission of bulk counterpart.     

ZnS∶Cu-罗丹明B的荧光共振能量转移性质

为了解决现有的基于量子点荧光共振能量转移体系的生物毒性问题,选用无毒的ZnS∶Cu量子点与罗丹明B构建新型荧光共振能量转移体系。通过共沉淀法成功制备了形貌均一的ZnS∶Cu纳米晶量子点。在此基础上,测试了不同掺杂浓度的ZnS∶Cu量子点及罗丹明B的荧光光谱。然后,通过对ZnS∶Cu量子点的表面修饰构建了以ZnS∶Cu量子点为供体、罗丹明B为受体的荧光共振能量转移体系。实验结果表明:ZnS∶2%Cu量子点的发光光谱与罗丹明B的吸收光谱在481 nm处有较大重合,说明构建荧光共振能量转移的最佳铜掺杂摩尔分数为2%。通过计算发现以ZnS∶2%Cu量子点为供体、罗丹明B为受体的荧光共振能量转移体系的能量转移效率为25.8%。进一步实验结果表明,罗丹明B浓度也能够影响能量转移。     

Synthesis of hollow silica-sulfur composite nanospheres towards stable lithium-sulfur battery

Herein, porous hollow silica nanospheres were prepared via a facile sol-gel process in an inverse microemulsion, using self-assemblies of chiral amphiphile as a soft template and fine water droplets as a hard template. The shells of the hollow silica nanospheres are composed of flake-like nanoparticles with dense big holes on the surface. After covering a layer of sulfur on the silica nanospheres, followed by hydrothermal treatment in a D-glucose aqueous solution, silica-sulfur and silica-sulfur-carbon nanospheres were successfully fabricated. The silica-sulfur composites exhibit a stable capacity of 454 mAh g^?1 at current density of 335 mA g^?1 after 100 cycles with capacity retention of 85%, demonstrating a promising cathode material for rechargeable lithium-sulfur batteries. We believe that the approach for synthesis of porous hollow silica nanospheres and its carbon spheroidal shell can also be applicable for designing other electrode materials for energy storage.