Correlation between aggregation structure and tailing mineral crystallinity

Direct reduction is an emerging technology for the utilization of refractory iron ore. With this technology, iron oxides in the ore can be reduced to recoverable elemental iron. The structure of granular aggregates in direct reduction products was investigated by X-ray diffraction (XRD). The results show that iron is mainly generated as a shell in the outer edge of the aggregates. The thermal conductivity of the iron shell is higher than that of other minerals. Thus, minerals close to the iron shell cool faster than those in the inner shells and do not crystallize well. These minerals mainly become stage 2 tailings. Hence the XRD intensity of stage 2 tailings is lower than that of stage 1 tailings. When iron is mainly generated in the interior of the aggregates, the crystallinity of stage 2 tailings will be higher than that of stage 1 tailings. This indicates that the crystallinity of tailings can be used as a marker for the aggregate structure.     

基于核壳荧光纳米颗粒的一种新型纳米pH传感器

改进了一种基于新型的荧光染料——二氧化硅的核壳荧光纳米颗粒的纳米pH传感器，以异硫氰酸荧光素(FITC)标记的羊抗人免疫球蛋白IgG为核材料，采用实验条件简单的油包水的微乳液方法制备荧光纳米颗粒，该方法有效地防止了荧光染料在二氧化硅壳层中的泄露。这种FITC的核壳荧光纳米颗粒对pH敏感，在pH值5．5—7之间呈线性响应，且能被单个小鼠巨噬细胞吞噬，借此用于单细胞中pH的实时监测。     

基于反相微乳液法的尺寸可控性二氧化硅纳米颗粒制备研究

通过考察水与表面活性剂的摩尔比(R),TEOS的量、氨水的量及包壳次数对基于Triton X - 100/环已烷/正已醇/水反相微乳液体系制备二氧化硅纳米颗粒尺寸的影响,开展了基于反相微乳液法的尺寸可控性二氧化硅纳米颗粒制备研究.结果表明:在其他参数都恒定的情况下,通过改变微乳液体系中上述某一组分的量,可以在一定程度上实现二氧化硅纳米颗粒的尺寸可控性合成.首先,水与表面活性剂的摩尔比(R)对二氧化硅纳米颗粒的尺寸影响最大,随着R值的增大,颗粒的粒径逐渐减小,当R值达到18时,二氧化硅纳米颗粒的形貌变得不再是很规则的球形结构,并且分散性降低,团聚现象明显;其次是氨水的量,随着氨水量的增多,颗粒的粒径先减小,之后不再发生明显变化;另外随着包壳次数的增多,颗粒的粒径随之增大,并且颗粒之间的分散性也有所提高;但是TEOS的量对颗粒粒径的影响不明显.     

Synthesis and characterization of bifunctional terbium complex-based nanoparticles

Novel bifunctional terbium complex-based nanoparticles were developed using a modified Stber method and a layer-by-layer assembly process. A magnetic core of Fe3O4 nanoparticles was coated with a silica shell to form the first layer. Then a ternary Tb3+ complex (TESPPA-Tb), which acted as a luminescent marker, was covalently bound to the silica surface by stable Si-O-Si bonds. The TESPPA monomer was synthesized by binding pyridine 2,6-dicarboxylic acid to 3-aminopropyltriethoxysilane, which was used as a ligand for coordination with the Tb3+ ions. An outer shell of silica was applied to the nanoparticles to allow for versatility with surface functionalization. The nanoparticles were characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, ultravioletvisible spectroscopy, vibration sample magnetometer, and photoluminescence spectroscopy. The bifunctional nanoparticles exhibited favorable superparamagnetic behavior and photoluminescence properties of Tb3+. These nanoparticles have potential applications in biolabeling, bioseparation, immunoassays, and pathogenic diagnosis.     

纳米半球壳结构光学调谐特性分析

利用离散偶极近似法,理论研究了颗粒几何结构参数和物理特性对金纳米半球壳颗粒消光特性的影响.结果表明,随着壳层厚度的增大,消光共振波长先发生蓝移而后再红移,共振波长转向时对应的壳层厚度随内核材料及外界环境介电常数和颗粒间距的增大而增大.利用等离激元杂化理论和相位延迟效应对该现象进行了解释.     

核桃壳吸附水中铁效能研究

为了研究核桃壳对铁的吸附性能,用云南产普通核桃壳进行除铁的静态吸附试验研究,考察核桃壳对铁的去除效果。结果表明核桃壳对铁有一定的去除效果。得到核桃壳的最佳投加量为500g/L,最佳吸附时间为120min,最佳吸附含铁浓度为0.1g/L,去除率可达94.56%。对铁的吸附规律较好地符合Freundlich吸附等温式。     

新型银-二氧化硅核-壳型复合纳米粒子的合成与表征

利用正四甲氧基硅在微乳液介质中的水解反应合成新型银 -二氧化硅核 -壳型复合纳米粒子 .通过化学反应调控 ,直径为 5～ 1 0 nm的金属银纳米粒子可以以单核或多核形式嵌入并分布于球型二氧化硅粒子中 .透射电子显微镜照片表明 ,该复合粒子具有高度均匀的粒径分布 .     

金/二氧化硅中空核壳纳米球的制备与表征

采用水热反应法和正硅酸乙酯水解法制备出核壳结构的Au/C纳米球颗粒以及夹层结构的Au/C/SiO<,2>纳米球颗粒,在空气中锻烧将Au/C/SiO<,2>夹层结构中的碳层除去,得到内部带有可移动纳米金核、壳层厚度约为20 nM的中空Au/SiO<,2>纳米球颗粒.用透射电子显微镜对所制得的纳米微球的形貌进行表征,并用红...     

Influences of ultrasonic irradiation on the morphology and structure of nanoporous Co nanoparticles during chemical dealloying

The Co-61.8 wt% Al nanoparticles of 45 nm were prepared by hydrogen plasma-metal reaction (HPMR) method. The nanoparticles display core shell structure with Al13Co4 and CoAl core and aluminum oxide shell (about 2 nm). Under ultrasonic irradiation, nanoporous fcc-Co nanoparticles were produced successfully by chemically dealloying the Co-Al nanoparticles at room temperature, whereas, without ultrasonic irradiation CoAl phase could hardly react with sodium hydroxide solution. At 323 K the Co-Al nanoparticles could be dealloyed to fcc-Co and hcp-Co phases even without ultrasonic irradiation. The surface area of the dealloyed nanoparticles under ultrasonic irradiation was larger than that of the dealloyed sample without ultrasonic irradiation at the same temperature. It is believed that the microjet and shock-wave induced by ultrasonic irradiation give rise to particles size reduction, interparticle collision and surface cleaning, and accelerate the dealloying process and the phase transformation.     

硬脂酸修饰铁掺杂TiO2纳米微粒制备及光催化性能

采用微乳法制备了铁掺杂TiO2和硬脂酸修饰铁掺杂TiO2纳米微粒,利用红外光谱、XRD等对结构进行表征.以0#柴油为含油模拟废水,对硬脂酸修饰铁掺杂TiO2的制备条件及光催化降解性能进行研究.结果表明,铁掺杂TiO2的光催化活性大于纯TiO2,铁最佳掺杂量为质量分数0.4％.硬脂酸修饰铁掺杂TiO2纳米微粒最佳修饰条件为,在超声波下温度30℃,时间40 min,硬脂酸与铁掺杂TiO2的质量分数6％.硬脂酸修饰铁掺杂TiO2纳米微粒催化降解含油废水效果最佳.     

CocorePdshell/C核壳型纳米粒子电催化氧还原性能

应用胶体粒子模板法制备不同壳层厚度的CocorePdshell纳米电催化剂。TEM、XRD和EDS证实,CocorePdshell纳米粒子基本为球形,面心立方晶型(fcc)Pd成功包覆在纳米金属Co的表面,其中,Co1Pd2纳米粒子平均直径约10 nm且粒径分布较窄。动电位、交流阻抗、循环伏安及原位傅里叶变换红外反射光谱等电化学测试结果表明:与Pd/C相比,CocorePdshell/C纳米粒子对氧还原反应(ORR)的活性有明显的提高,甚至接近于Pt/C;抗甲醇能力非常优异,对甲醇氧化几乎无活性;不同壳层厚度催化剂中,以Co1Pd2/C催化剂的活性最高,在0.5 mol/L H2SO4中氧还原峰电流密度可达175.5 mA/mg,比Pt/C的要高出20 mA/mg。     

Fe_3O_4@Au核壳结构的制备及在苯乙烯环氧化中的研究

以FeCl3·6H2O为铁源,乙二醇为还原剂,聚乙二醇为表面活性剂,在200℃水热条件下制备平均粒径约为300 nm的介孔Fe3O4.以3-氨丙基三乙氧基硅烷(APTES)为偶联剂对Fe3O4进行改性,室温超声下用柠檬酸钠将Au3+还原为Au0,制备了Fe3O4@Au核壳材料.利用扫描电镜(SEM),N2-吸附-脱附等温线,X射线衍射(XRD),傅里叶变换红外对核壳材料进行表征,结果表明,比表面为95.56 m2/g、孔径为5.67 nm,Fe3O4表面被金均匀涂层,其具有较好的光催化环氧化选择性.     

以PS-P2VP嵌段共聚物为模板获得金-氧化铁复合纳米粒子有序排列

采用具有两亲性的嵌段共聚物聚苯乙烯-b-聚二乙烯基吡啶嵌段物(PS-P2VP),与无机前躯体FeCl3和HAuCl4.xH2O在选择性溶剂甲苯中自组装,得到以P2VP/FeCl3/HAuCl4为核、PS为壳的球形胶束;硅片上的胶束经磞氢化钠水溶液还原后用紫外灯降解除去PS-P2VP后得到复合粒子。经场发射扫描电镜、扫描探针显微镜、X射线光电子能谱分析仪等表征及检测,结果表明:在2.2 keV和6.4 keV处分别检测出金和铁元素的信号峰,得到有序排列的金-氧化铁复合纳米粒子。     

Non-symmetric hybrids of noble metal-semiconductor: Interplay of nanoparticles and nanostructures in formation dynamics and plasmonic applications

Noble metal-semiconductor hybrids have been employed as fundamental structures in modern technologies. In these hybrids, their cooperative multiple functions attract much attention in recent years because of the interplay of nanoparticles and nanostructures. In this review, we summarize the interplay of nanoparticles and nanostructures in specific kinds of noble metal-semiconductor hybrids, termed as non-symmetric hybrids of noble metal-semiconductor. It particularly refers to metal nanoparticles (or semiconducting quantum dots) at 1-dimensinal (1D) and 2-dimensional (2D) semiconductor (or metal) nanostructures, in contrast to the core/shell and heterodimer nanostructures. First, we discuss the formation dynamics, especially in chemical growth and assembly as well as physical coating and deposition, of non-symmetric noble metal-semiconductor hybrids with nanoparticles on nanostructures. Second, we introduce the plasmon-related applications of these hybrids in heterogeneous catalysis, optoelectronic or photovoltaic devices, all-optical devices, and surface detection or modulation. This review not only provides a comprehensive understanding of the formation mechanisms of the non-symmetric metal-semiconductor hybrid nanostructures, but also may inspire new ideas of novel functional devices and applications based on these systems.     

Preparation of luminescent CdTe quantum dots doped core-shell nanoparticles and their application in cell recognition

Quantum dots (QDs), often referring to “semiconductor nanocrystals”, have gained increasing attention in the past decade due to their unique optical properties compared with conventional organic fluorophore[1]. In the fields of biochemistry, cell biology and molecular biology, water- soluble QDs have played many important roles[2 - 8]. However, luminescent QDs are usually prepared in or-ganic solvents and the products are not water soluble, which make them unsuitable for biological applica…     

Development and application of tumor-targeting magnetic nanoparticles FA-StNP@Fe2O3 for hyperthermia

Modified magnetic starch nanoparticles （FA-StNP@Fe2O3） were synthesized by conjugating folic acid （FA-PEG-NH2） onto the surface of magnetic starch nanoparticles （StNP@Fe2O3） prepared by reverse microemulsion method. The synthesized FA-StNP@Fe2O3 was investigated by transmission electron microscopy and zeta potential analysis. The average size of its well dispersed particles was 250 nm. The iron concentration of 2 mg/g was detected by phenanthroline method. Placing FA-StNP@Fe2O3 nanoparticles in the alternating magnetic field for 30 min resulted in an increase in the suspension temperature from ambient temperature （37℃） to a value between 42℃ and 43℃. Co-cultured nanoparticles and Hela cell line or normal HUEC-12 cell line, and the biological effects at the cellular level were investigated in the alternating magnetic field using MTT assay, Hochest-PI double staining and flow cytometry analysis. Experimental results showed that FA-StNP@Fe2O3 within acertain concentration range has no obvious effect on cell proliferation. When treated in the magnetic field, apoptosis rate on Hela induced by FA-StNP@Fe2O3 was 13.4%. Prussian blue staining analysis confirmed that the nanoparticles modified with folic acid had improved ability in tumor cell-targeting, and therefore, potential applications in biomedical and magnetocaloric areas. It is expected be applied in tumor targeting therapy in the near future.     

典型阴离子对纳米二氧化钛在载铁石英砂 多孔介质中迁移行为的影响

以纳米二氧化钛为研究对象,考察系列环境相关条件下(不同pH、离子类型与离子强度)纳米二氧化钛在载铁石英砂多孔介质中的迁移规律。结果表明,纳米二氧化钛在NaCl,NaNO_3和Na_2SO_4 3种溶液中的穿透曲线和滞留曲线没有显著差异,但与其他溶液相比,在NaH_2PO_4溶液中的穿透曲线和滞留曲线分别有明显的升高和降低;磷酸根离子会促进纳米二氧化钛在载铁石英砂多孔介质中的迁移行为。机理探究发现,由于PO_4~(3-)会被吸附至纳米二氧化钛和载铁石英砂多孔介质的表面上,增大纳米二氧化钛和多孔介质的表面Zeta电位,导致纳米二氧化钛与介质表面之间静电斥力的增加,从而加大纳米二氧化钛被吸附于多孔介质表面位点的难度,减少沉积;同时,纳米二氧化钛Zeta电位的增加会减少纳米二氧化钛颗粒间的碰撞团聚,导致其水力学粒径变小,从而促进其迁移行为。此外,PO_4~(3-)会与纳米二氧化钛竞争多孔介质表面的吸附位点,导致纳米二氧化钛可沉积位点的减少,增加迁移能力。     

二氧化钛包裹竹红菌素纳米粒的制备和表征

采用溶胶-凝胶法合成二氧化钛包裹竹红菌素纳米粒,并利用透射电镜和粒度分析仪对其形貌和粒子大小进行测定,证明粒子呈球形,平均直径在100 nm左右;采用紫外和荧光光谱研究二氧化钛包裹竹红菌素纳米粒的光谱性质,并与未包裹的竹红菌素在水溶液中的光谱性质进行了比较,结果表明,竹红菌素被成功地包裹于二氧化钛纳米粒中;包裹后竹红菌素的光谱吸收峰红移,强度增加.由此,将有利于竹红菌素在光动力疗法中的应用.     

核壳型Ni-Pt纳米微粒的氧还原电催化性能

应用化学还原两步法制备了壳层厚度不同的Ni-Pt核壳型纳米粒子,并用XRD,XPS,TEM,SEM技术表征了微粒的表面元素组成和物理结构,用动电位扫描法考察了该纳米粒子对氧还原反应的电催化活性。实验结果表明,合成的Ni-Pt微粒为球形核壳结构纳米粒子,外直径平均值约30 nm,Ni核直径约17 nm,Pt壳层厚度约8 nm;核壳Ni-Pt/C相对Pt/C具有更高的电催化氧还原活性和抗甲醇性,电催化氧还原活性和抗甲醇能力随Pt壳层厚度改变有明显变化,变化的规律呈火山形,核壳Ni-Pt/C催化性能随Pt壳层厚度改变的机理符合"d电子调变效应"机理。     

阿昔洛韦/赖氨酸壳聚糖纳米粒的理化性质考察

考察阿昔洛韦/赖氨酸壳聚糖纳米粒的理化性质。利用激光粒度分析仪、透射电镜、扫描电镜、高效液相色谱仪等测定载药纳米粒的形态、粒径、包封率和载药量,并考察载药纳米粒的体外释放行为。考察结果,微球呈类圆形,具有明显的核壳;载药的粒子平均粒径大小为107.96 nm;包封率为(61.24±0.68)%;载药量为(15.36±0.65)%;体外释放符合Higuchi模型。结论:阿昔洛韦/赖氨酸壳聚糖纳米粒理化性能具有良好的稳定性,符合实验设计要求。