大洋多金属结核与富钴结壳浸出渣的纳米属性

对大洋多金属结核经氨浸提取Co,Ni,Cu后的固体残渣（氨浸渣）以及富钴结壳经酸浸提取Co,Ni,Cu,Zn,Mn后的固体残渣（酸浸渣）的物相、成分和物化性能进行了系统研究.结果表明,氨浸渣和酸浸渣都含有大量纳米矿物,前者以菱锰矿为主,平均粒径为17.9nm;后者以半水石膏为主,平均粒径为9.5nm.半水石膏具有孔道结构,孔体积为1.23×10-2mL/g.氨浸渣和酸浸渣的比表面积较大,对饱和NaCl水蒸气、N_2和SO_2气体的吸附能力强.稀土元素含量都很高,多呈离子吸附态存在.∑FeO含量高,且酸浸渣中P_2O_5明显富集.浸出渣独特的成分和纳米固体属性,预示其在环保及材料领域具有良好的应用前景和潜在价值.

天津蓟县二维纳米级伊利石研究

天津蓟县中元古界串岭沟组上部黑色页岩产有丰富的伊利石,其矿物组合仅为石英和伊利石,是重要的可利用伊利石资源。运用化学成分分析和XRD方法确定出伊利石含量为6 4 %～70 %。由Scherrer方程计算的平均c* 轴方向厚度为12 nm,平均b轴方向长度为16 7nm,结合伊利石的片状生长习性,可确定串岭沟组上部黑色页岩所产伊利石为二维纳米级伊利石,具有重要的纳米属性。化学成分分析表明,黑色页岩所产伊利石具有0 .75的层间电荷和二八面体为主的二八—三八面体的过渡类型八面体结构特点。对数正态粒度大小的分布特征表明黑色页岩中的伊利石经历了由成核→等体积转移→最终长大的Ostwald成熟效应。

碳纳米管定向网络场效应晶体管的制备及特性

目的采用简单易行的方法,制备以碳纳米管定向网络为导电沟道的场效应晶体管。方法采用氧化及酸处理的方法对碳纳米管进行提纯,用高频交流电泳在电极间形成碳纳米管的定向网络,并据碳纳米管的导电特性确定半导体性碳纳米管的耗尽栅压,利用大电流烧蚀法去除金属性碳纳米管。结果制备出背栅型碳纳米管定向网络场效应晶体管,测量了输出特性。结论经过提纯处理的碳纳米管纯度提高,碳纳米管在电极间的定向分布效果随交流电场频率的提高而改善,制备出的碳纳米管场效应晶体管具备一定的场效应特性。

短纤维石棉制备纤维状SiO_2的原理与方法

对纤蛇纹石石棉的化学成分、晶体结构、形态特征和活性进行了研究,探讨了纤蛇纹石石棉制备纤维状纳米S iO2的原理,并对试验产物进行了分析。结果表明:纤蛇纹石石棉是天然产出的纳米管状材料,其内管直径为3.5~24 nm,多数小于11 nm,外管直径为16~56 nm,绝大多数在20~50 nm范围内。纯净的纤蛇纹石石棉样品的化学成分主要为S iO2、MgO和H2O+,其质量分数S iO2约为42%,MgO约为42%,结构水H2O+约为13%。纤蛇纹石具有卷管状结构,化学键特点决定了其具有很好的化学活性和可改造性,为制备纤维状纳米S iO2粉体材料创造了基础。纤蛇纹石石棉纤维经酸处理后,MgO等组分被浸取出来转变为硫酸盐,而残留下非晶质纳米S iO2纤维残骸;经后处理即可获得纤维状S iO2纳米材料。

Fabrication of Poly（y-glutamic acid）-coated Fe3O4 Magnetic Nanoparticles and Their Application in Heavy Metal Removal

In this study, poly（y-glutamic acid）-coated Fe3O4 magnetic nanoparticles （y-PGA/Fe304 MNPs） were successfully fabricated using the co-precipitation method. Fe3O4 MNPs were also prepared for comparison. The av erage size and specific surface area results reveal that 7-PGA/Fe304 MNPs （52.4 nm, 88.41 m2.g-1） have smaller particle size and larger specific surface area_ than Fe3O4 MNPs （62.0 nm, 76.83 mLg-1）. The y-PGA/Fe3O4 MNPs

Anisotropic gold nanoparticles: Preparation and applications in catalysis

Despite the high amount of scientific work dedicated to the gold nanoparticles in catalysis, most of the research has been performed utilising supported nanoparticles obtained by traditional impreg‐nation of gold salts onto a support, co‐precipitation or deposition‐precipitation methods which do not benefit from the recent advances in nanotechnologies. Only more recently, gold catalyst scien‐tists have been exploiting the potential of preforming the metal nanoparticles in a colloidal suspen‐sion before immobilisation with great results in terms of catalytic activity and the morphology con‐trol of mono‐and bimetallic catalysts. On the other hand, the last decade has seen the emergence of more advanced control in gold metal nanoparticle synthesis, resulting in a variety of anisotropic gold nanoparticles with easily accessible new morphologies that offer control over the coordination of surface atoms and the optical properties of the nanoparticles （tunable plasmon band） with im‐mense relevance for catalysis. Such morphologies include nanorods, nanostars, nanoflowers, den‐dritic nanostructures or polyhedral nanoparticles to mention a few. In addition to highlighting newly developed methods and properties of anisotropic gold nanoparticles, in this review we ex‐amine the emerging literature that clearly indicates the often superior catalytic performance and amazing potential of these nanoparticles to transform the field of heterogeneous catalysis by gold by offering potentially higher catalytic performance, control over exposed active sites, robustness and tunability for thermal‐, electro‐and photocatalysis.

Coating for Nano Super Soil-repellency of Cashmere Fabric

The nano-size metal oxide was prepared by the single-disperse technique on liquid phase, and formed sol dusters, its uniform film was covered on the surface of cashmere fibers by coating, and it had good oil repellency and water repellency. The results of IR（infrared） Spectrometer analysis revealed： The nano material combines through the strong bonds with the surface of cashmere fibers by the live groups. These analyses by SEM techniques showed that the nano material was distributed on the fiber surface even, and the nano material formed the strong peak of the regular crystal phase structure using the X-Ray Diffractometry （XRD） to analysis the fabric. The optimum techniques were selected by a series of experiments, coated cashmere fabric not only has preserved original properties of softness and comfort, but also has good properties of Bi-repellency function. Therefore, the technique will have potential appfication in engineers.

Protein Templated Au-CuO Bimetallic Nanoclusters toward Neutral Glucose Sensing

In this study,the application of bovine serum albumin(BSA)as a carrier to glucose-sensitive materials for the detection of glucose was proposed.Au-Cu O bimetallic nanoclusters(Au-Cu O/BSA)were prepared using BSA as a template,the new sensing material(Au-Cu O/BSA/MWCNTs)was synthesized by mixing with multi-walled carbon nanotubes(MWCNT)and applied to non-enzymatic electrochemical sensors to detect glucose stably and effectively under neutral condition.The scanning electron microscopy was used to investigate the morphology of the synthesized nanocomposite.The electrochemical properties of the sensor were studied by cyclic voltammetry.Glucose detection experiments show that Au-Cu O/BSA/MWCNTs/Au electrode has good glucose detection ability,stability,accuracy,repeatability,and high selectivity in neutral environment.Unlike existing glucose-sensitive materials,due to the use of BSA,the composite material is firmly fixed to the electrode surface without a Nafion solution,which reduces the current blocking effect on the modified electrode.The composite materials can be effectively preserved for extremely long periods,higher than 80%activity is maintained at room temperature in a closed environment for 3 to 4 months,due to the special effects of BSA.In addition,the feasibility of using BSA in glucose-sensitive materials is confirmed.

Comparative study on photocatalytic properties of TiO_2 nanoparticles prepared in acidic medium and basic medium by hydrothermal method

In order to investigate the difference of phtotocatalytic properties of TiO2 samples prepared in different pH conditions, TiO2 nanopartieles were prepared in acidic medium and basic medium by a hydrothermal process, respectively. The samples were characterized using XRD, TEM, BET, XPS, surface photovoltage spectroscopy （SPS） and field-induced surface photovohage spectroscopy （FISPS）. Effects of temperature and pH in the hydrothermal process on particle sizes, specific surface areas, and photoeatalytic properties of the TiO2 nanoerystalline were investigated. The experimental results indicate that the photocatalysis activity of TiO2 nanoparticles prepared in basic medium （ B-TiO2 ） is superior to that in acidic medium （ A-TiO2 ）, which is ascribed to the difference of surface state between A-TiO2 and B-TiO2.

Modeling infrared radiative properties of nanoscale metallic complex slit arrays

The radiative properties(absorptance, reflectance, and transmittance) of deep slits with five nanoscale slit profile variations at the transverse magnetic wave incidence were numerically investigated by employing the finite difference time domain method. For slits with attached features, their radiative properties can be much different due to the modified cavity geometry and dangled structures, even at wavelengths between 3 and 15 μm. The shifts of cavity resonance excitation result in higher transmittance through narrower slits at specific wavelengths and resonance modes are confirmed with the electromagnetic fields. Opposite roles possibly played by features in increasing or decreasing absorptance are determined by the feature position and demonstrated by Poynting vectors. Correlations among all properties of a representative slit array and the slit density are also comprehensively studied. When multiple slit types coexist in an array(complex slits), a wide-band transmittance or absorptance enhancement is feasible by merging spectral peaks contributed from each type of slits distinctively. Discrepancy among infrared properties of four selected slit combinations is explained while effects of slit density are also discussed.

Electrical properties of carbon nanotubes in flowing vapor

Electric potentials were generated from carbon nanotubes immersed in flowing vapors. The nanomaterials used in this study were multiwall carbon nanotubes（MWCNTs） and silver nanopowders. These nanomaterials were dispersed and densely packed on a substrate and immersed in flowing vapors generated from solution such as water, ethanol and KCI. The potentials generated from these samples were measured by a voltmeter. Experimental results showed that the electric potentials were produced at the surface of the MWCNT samlpes, and strongly dependent on the pretreatment of MWCNT and properties of the flowing vapors. The mechanism of vapor-flow induced potentials may be ascribed to ions in the flowing vapors. This property of MWCNTs can advantage their application to nanoscale sensors, detectors and power cells.

Studies on Preparation and Properties of Proton Exchange Membranes Based on Phosphotungstic Acid/Silica and Polysulfonamide

Membranes formed by polysulfonamide(PSA)and phosphotungstic acid(PWA)supported on nano-silica have been prepared.Fourier transform infrared spectra(FTIR)and thermogravimetric analysis(TGA)were used to characterize the structure and thermal properties of obtained membranes.The analyses of water uptake,proton conductivity and mechanical properties of the membranes revealed that PWA and silica produced a beneficial effect on proton conduction of the membranes.The membranes with 50 wt% of PWA-SiO2 /PSA were mechanically stable and gave proton conductivity of 2.57×10-2 S·cm-1 at 90℃ and 100% relative humidity.According to the obtained results,PWA and SiO2 doped PSA is a promising material for proton exchange membrane.

Facile and Efficient Method for the Adsorption and Separation of Lanthanum Rare Earth Metal Oxide Using Iron（Ⅱ） Sulfide Nanoparticles Coated on Magnetite

A novel iron sulphide adsorbent using magnetite embedded with nanosized Fe3O4 was prepared and applied to separation lanthanum （Ⅲ） from aqueous solution. This adsorbent combines the advantages of magnetic nanoparticle with magnetic separability and high affinity toward rare earth metals, which provides distinctive merits including easy preparation, high adsorption capacity, easy isolation from sample solutions by the application of an external magnetic field. The adsorption behaviors of lanthanum （Ⅲ） from an aqueous medium, using iron sulphide magnetite nanoparticles were studied using equilibrium batch and column flow techniques. The effect ofpH, contents of loaded iron sulphide nanoparticles, ionic strength, adsorbent dose, contact time, and temperature on adsorption capacity of the magnetic beads was investigated. All of the results suggested that the FeS/Fe3O4 Nanoparticles could be excellent adsorbents for La（Ⅲ） contaminated water treatment.

Effective Approach for the Synthesis of Monodisperse Magnetic Nanocrystals and M-Fe3O4 （M = Ag, Au, Pt, Pd） Heterostructures

Monodisperse and size-tunable magnetic iron oxide nanoparticles （NPs） have been synthesized by thermal decomposition of an iron oleate complex at 310 ℃ in the presence of oleylamine and oleic acid. The diameters of the as-synthesized iron oxide NPs decrease with increasing concentrations of iron oleate complex and oleic acid/oleylamine. In addition, the size-dependent crystallinity and magnetic properties of iron oxide NPs are presented. It is found that larger iron oxide NPs have a higher degree of crystallinity and saturation magnetization. More importantly, various M-iron oxide heterostructures （M = Au, Ag, Pt, Pd） have been successfully fabricated by using the same synthesis procedure. The iron oxide NPs are grown over the pre-made metal seeds through a seed-mediated growth process. The physicochemical properties of Au-Fe3O4 heterostructures have been characterized by X-ray diffraction （XRD）, superconducting quantum interference device （SQUID） magnetometry and UV-vis spectroscopy. The as-synthesized Au-Fe3O4 heterostructures show a red-shift in surface plasmon resonance peak compared with Au NPs and similar magnetic properties to Fe3O4 NPs. The heterojunction effects present in such nanostructures offer the opportunity to tune the irphysicochemical properties. Therefore, this synthesis process can be regarded as an efficient way to fabricate a series of heterostructures for a variety of applications.

Ultrasmall Ag^＋-rich nanoclusters as highly efficient nanoreservoirs for bacterial killing

Metallic silver （Ag） and its ability to combat infection have been known since ancient history. In the wake of nanotechnology advancement, silver＇s efficacy to fight broad spectrum bacterial infections is further improved in the form of Ag nanoparticles （NPs）. Recent studies have ascribed the broad spectrum antimicrobial properties of Ag NPs to dissociation of Ag＊ ions from the NPs, which may not be entirely applicable when the size of Ag NPs decreases to the sub-2 nm range [denoted Ag nanoclusters （NCs）]. In this paper we report that ultrasmall glutathione （GSH）-protected Ag^＋-rich NCs （Ag^＋-R NCs for short, with a predominance of Ag＋ species in the NCs） have much higher antimicrobial activities towards both gram-negative and gram-positive bacteria than the reference NC, GSH-Ag^＋-R NCs. They have the same size and surface ligand, but with different oxidation states of the core silver. This interesting finding suggests that the undissociated Ag^＋-R NCs armed with abundant Ag^＋ ions on the surface are highly active in bacterial killing, which was not observed in the system of their larger counterpart, Ag NPs.

Conditions for magnetic and electronic properties of ultrathin Ni–Fe hydroxide nanosheets as catalysts:a DFT+U study

The effects of cation ordering and surface compensating anions on the magnetic structure and catalytic properties of unilamellar Ni-Fe hydroxide nanosheets are studied by using the density functional theory （DFT） plus U method. Fe-segregation in the nanosheets yields magnetic domains with different spin alignments, while the surface compensating anions affect the local moments and valence states of the Fe atoms. The two conditions do not radically change the super-exchange nature of interactions between the paramagnetic metal centers, hut facilitate the formation of various magnetic superlattices in the nanosheets. The calculated free energy change of the intermediates shows that the most stable magnetic structure of Ni-Fe hydrox- ide nanosheets exhibits superior catalytic activity towards oxygen reduction/evolution reactions, which is indicative of magnetic catalyst. This is due to the cycle transition between Fe2＋ and Fe~~ ions in the reactions, which determines the sequence of cleavage of the O-H bond and the release of the OH group, controlling the rate-limiting steps of the reaction. The relationship of magnetism and catalytic activity of Ni-Fe hydroxide nanosheets is established by the valence state change of the Fe ions, which will be helpful to open the way for the design of hydroxide/layered double hydroxides （LDHs）-based magnetic catalysts.

PdPb bimetallic nanowires as electrocatalysts for enhanced ethanol electrooxidation

Less-expensive but efficient electrocatalysts are essential to accelerate the commercialization of fuel cells.Herein,ultrathin PdPb nanowires(PdPb NWs)with a diameter of around 3.5 nm were prepared by using a one-step hydrothermal method.The introduction of Pb in Pd-based bimetallic nanostructures produced high differences in the morphology from Pd nanoparticles(NPs)to various PdPb NWs.All the as-prepared PdPb NWs exhibited better electrocatalytic activity and durability than Pd NPs due to the synergistic effect.Especially,Pd65Pb35 possessed the highest current density of about 3460 mA mgPd^−1 for the ethanol electrooxidation which was around 6.3 times higher than commercial Pd/C.The high-performance of Pd65Pb35 is attributed to the defect-rich and stable nanowire structure with optimized surface atomic arrangement,as evidenced by high resolution transmission electron microscopy measurements and long-time treatment in an acidic media.The differences in the morphologies and electrocatalytic activities of PdPb NWs with varied Pb contents have also been discussed and analyzed.

Highly reactive, flexible yet green Se precursor for metal selenide nanocrystals： Se-octadecene suspension （Se-SUS）

A suspension of fine selenium （Se） powder （100 or 200 mesh） in octadecene （Se-SUS） has proven to be a high-performance, versatile, convenient, reproducible, yet green Se precursor. The advantages of Se-SUS arise from its highly reactive chemical nature and flexibility. These two features made it possible to carry out the synthesis of high quality metal selenide nanocrystals with diverse compositions and structures, including binary, core/shelL transition metal doped, and complex composition nanocrystals. These successes further demonstrated that Se-SUS is a powerful Se precursor for solving a few long- standing challenges in the synthesis of high quality selenide nanocrystals. For instance, Se-SUS was successfully employed as a Se precursor for shell growth in high quality core/shell nanocrystals to replace expensive and highly toxic precursors, such as Se-phosphine and bis-trimethylsilyl selenide, with greatly lowered epitaxial temperatures （as low as 150℃） to avoid alloying. As another example, Se-SUS enabled ＂co-nucleation doping＂ as a means of preparing high quality Mn doped ZnSe nanocrystals with pure, stable, and highly efficient dopant fluorescence.

The influence of the crystalline nature of nano-metal oxides on their antibacterial and toxicity properties

The antibacterial properties of nano-metal oxides （ZnO, CuO） are based on the formation of reactive oxygen species （ROS）. This work reveals that the antibacterial properties of these nano-metal oxides are strongly dependent on their crystalline structure. The antibacterial activity of the nanooxides was tested against four types of bacteria that commonly cause nosocomial infections. The sonochemical method was applied not only for synthesis of nanooxides but also to their coating on textiles. The antibacterial properties of textiles coated with commercial and sonochemically prepared nano-metal oxides were evaluated and compared. The toxicity was evaluated on human lung cells and amphibian embryos, as representative models for inhalation and aquatic toxicology. The sonochemically prepared metal nanooxides are better antimicrobials than commercially available metal oxides with the same particle size range. It was found that the crystallites which have more defects and less organized structure are more toxic. The formation of ROS was studied by electron spin resonance （ESR） measurements for both the sonochemically prepared and commercial samples of ZnO/CuO nanoparticles. A significant increase in the production of radical species was found in the more defective, sonochemically prepared samples, as compared to the commercial ones. Since modulation of the nanoparticle defects influenced their toxicity, the possibility of engineering safer nano-antibacterials is indicated.

Optical properties of dyes with/without metal nanoparticles doped in a highly ordered nanostructure

Highly ordered nanocomposite arrays of Rh6G-Au-AAO are formed by filling anodized aluminum oxide （AAO） with Rhodamine 6G （Rh6G） and gold nanoparticles. The optical properties of Rh6G-Au-AAO are studied by visible absorptive and fluorescent spectroscopy. Compared with the fluorescence spectra of Rh6G-Au in the solution environment, the fluo- rescence peak intensities of Rh6G-Au-AAO are significantly enhanced, the maximum enhancement rate is 5.5, and a constant blue shift of-12 nm of peak positions is presented. The effects come from the spatial confinement of AAO and the inhibition of the fluorescence quenching effect induced by gold nanoparticles. The results show that the nanocomposite structures of fluorescence molecules-metal nanoparticles-AAO have a considerable potential in engineering molecular assemblies and creating functional materials of superior properties for future nanoDhotonics.