Nanostructured ZnO synthesis and its application for effective disinfection of <Emphasis Type="Italic">Escherichia coli</Emphasis> micro organism in water

Nanostructured ZnO photo catalyst was synthesized by precipitation method and was applied in conjunction with 355 nm pulsed laser irradiation for effective disinfection of the water contaminated with Escherichia coli micro organism. The morphological studies using X-Ray Diffractometer (XRD) and Transmission Electron Microscope (TEM) were carried out on the synthesized nano-ZnO, and these studies indicated that the catalyst has the crystallographic structure of hexagonal wurtzite and has the grain size of around 20–40 nm. The bacteria decay rate constants were estimated for nine different concentrations of nano-ZnO in infected water. The parametric optimization was carried out, and we could reach the decay rate constant as high as 0.24 min_,⁻¹ which is higher than micro-structured ZnO and the familiar TiO₂ photo catalysts under similar experimental condition.     

Structural properties of nano 5, 10, 15, 20-Tetraphenyl-21H,23H-porphine nickel (II) thin films

Thin films of 5,10,15,20-Tetraphenyl-21H,23H-porphine-nickel(II) were prepared by thermal evaporation technique onto clean quartz and glass substrates. Thermogravimetric analysis, X-Ray Diffraction, Scanning Electron Microscope, Transmission Electron Microscope and Fourier transforms infrared spectroscopy were used to investigate the structural properties of the as-prepared and annealed 5,10,15,20-Tetraphenyl-21H,23H-porphine-nickel(II) films. Morphology, crystallite size and dislocation density were enhanced by annealing and included within nanometric scale. The crystallite sizes were 98 nm for powder form and 13, 41.4 and 64.7 nm for the annealed films at 373, 473 and 573 K respectively. Fourier transforms infrared spectroscopy studies released that powder, as-prepared and annealed NiTPP films were stoichiometric. The obtained films were characterized by nanostructure property.     

Effect of annealing temperature on optical and magnetic properties of Cr doped ZnS nanoparticles

ZnS:Cr (3 at.%) nanoparticles were synthesized by chemical co-precipitation method using EDTA as capping agent. The samples were annealed in air for 3 h in steps of 100 °C in the temperature range of 200–700 °C. The effect of annealing temperatures on the structural and photoluminescence properties of Cr doped ZnS nanoparticles was investigated using X-ray Diffraction (XRD), a Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDS), Diffuse Reflectance Spectra (DRS), Vibrating Sample Magnetometer (VSM) and Photoluminescence (PL) techniques. EDS spectra confirmed the presence of Cr in the samples with expected stoichiometry. XRD studies confirmed the formation of ZnO above 500 °C. Photoluminescence studies on ZnS:Cr nanoparticles indicated that the emission wavelength is tunable in the range of 440–675 nm as a function of annealing temperature. VSM results indicated a decrease in ferromagnetism with increase in annealing temperature, perhaps due to appreciable variation in structural defects that are sensitive to annealing temperature.     

Synthesis and magnetic properties of cobalt ferrite (CoFe2O4) nanoparticles prepared by wet chemical route

Magnetic nanoparticles of cobalt ferrite have been synthesized by wet chemical method using stable ferric and cobalt salts with oleic acid as the surfactant. X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM) confirmed the formation of single-phase cobalt ferrite nanoparticles in the range 15–48 nm depending on the annealing temperature and time. The size of the particles increases with annealing temperature and time while the coercivity goes through a maximum, peaking at around 28 nm. A very large coercivity (10.5 kOe) is observed on cooling down to 77 K while typical blocking effects are observed below about 260 K. The high field moment is observed to be small for smaller particles and approaches the bulk value for large particles.     

Cadmium sulfide quantum dots stabilized by castor oil and ricinoleic acid

Castor oil and ricinoleic acid (an isolate of castor oil) are environmentally friendly bio-based organic surfactants that have been used as capping agents to prepare nearly spherical cadmium sulfide quantum dots (QDs) at 230, 250 and 280 °C. The prepared quantum dots were characterized by Ultra violet–visible (UV–vis), Photoluminescence (PL), Transmission Electron Microscopy (TEM), High Resolution Transmission Electron Microscopy (HRTEM) and X-ray diffraction (XRD) giving an overall CdS QDs average size of 5.14±0.39 nm. The broad XRD pattern and crystal lattice fringes in the HRTEM images showed a hexagonal phase composition of the CdS QDs. The calculated/estimated average size of the prepared castor oil capped CdS QDs for various techniques were 4.64 nm (TEM), 4.65 nm (EMA), 5.35 nm (UV–vis) and 6.46 nm (XRD). For ricinoleic acid capped CdS QDs, the average sizes were 5.56 nm (TEM), 4.78 nm (EMA), 5.52 nm (UV–vis) and 8.21 nm (XRD). Optical properties of CdS QDs showed a change of band gap energy from its bulk band gap of 2.42–2.82 eV due to quantum size confinement effect for temperature range of 230–280 °C. Similarly, a blue shift was observed in the photoluminescence spectra. Scanning electron microscope (SEM) observations show that the as-synthesized CdS QDs structures are spherical in shape. Fourier transform infra-red (FTIR) studies confirms the formation of castor oil and ricinoleic acid capped CdS QDs.     

Release studies of corrosion inhibitors from cerium titanium oxide nanocontainers

Cerium titanium oxide nanocontainers were synthesized through a two-step process and then loaded with corrosion inhibitors 2-mercaptobenzothiazole (2-MB) and 8-hydroxyquinoline (8-HQ). First, polystyrene nanospheres (PS) were produced using polymerization in suspension. Second, the PS spheres were coated via the sol–gel method to form a cerium titanium oxide layer. Finally, the nanocontainers were made by calcination of the coated PS nanospheres. The size of the containers was 180 ± 10 nm as determined by Scanning Electron Microscopy (SEM). X-Ray Diffraction Analysis (XRD) showed that the nanocontainers consist of anatase and cerianite crystalline phases. The presence and loading of the inhibitors in the nanocontainers was confirmed with Fourier Transform Infrared Spectroscopy (FT–IR) and Thermo Gravimetric Analysis (TGA), respectively. TGA revealed the amount of 10.43 and 4.61% w/w for 2-MB and 8-HQ in the nanocontainers, respectively. Furthermore, the release kinetics of the inhibitors from the nanocontainers was studied in corrosive environment using electrochemical impedance spectroscopy (EIS) in the presence of aluminum alloys 2024-T3 (AA2024-T3).     

Magnetic properties of xNi0.53Cu0.12Zn0.35Fe1.88O4+(1−x)BaTiO3 nanocomposites

The nanocrystalline Ni_0.53Cu_0.12Zn_0.35Fe_1.88O₄ and BaTiO₃ powders were prepared using Microwave-Hydrothermal (M-H) method at 160 °C/45 min. The as synthesized powders were characterized using the X-ray diffraction (XRD) and Transmission Electron Microscope (TEM). The size of the powders that were synthesized using M-H system was found to be ∼30 and ∼50 nm for ferrite phase and ferroelectric phases, respectively. The powders were densified using microwave sintering method at 900 °C/30 min. The ferrite and ferroelectric phases were observed from XRD and morphology of the composites was observed with the Scanning Electron Microscope (SEM).The magnetic hysteresis loops were recorded using the Vibrating Sample Magnetometer (VSM).The frequency dependence of real (μ′) and imaginary (μ″) parts of permeability was measured in the range of 1 MHz-1.8 GHz. The permeability decreases with an increase of BaTiO₃ content at 1 MHz. The transition temperature (T_C) of ferrite was found to be 245 °C. The T_C of composite materials decreases with an increase in BaTiO₃ content.     

Investigation of different liquid media and ablation times on pulsed laser ablation synthesis of aluminum nanoparticles

Aluminum nanoparticles were synthesized by pulsed laser ablation of Al targets in ethanol, acetone, and ethylene glycol. Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) images, Particle size distribution diagram from Laser Particle Size Analyzer (LPSA), UV-visible absorption spectra, and weight changes of targets were used for the characterization and comparison of products. The experiments demonstrated that ablation efficiency in ethylene glycol is too low, in ethanol is higher, and in acetone is highest. Comparison between ethanol and acetone clarified that acetone medium leads to finer nanoparticles (mean diameter of 30 nm) with narrower size distribution (from 10 to 100 nm). However, thin carbon layer coats some of them, which was not observed in ethanol medium. It was also revealed that higher ablation time resulted in higher ablated mass, but lower ablation rate. Finer nanoparticles, moreover, were synthesized in higher ablation times.     

Poly(amidehydroxyurethane) template magnetite nanoparticles electrosynthesis: I. Electrochemical aspects and identification

A new method for the electrochemical synthesis and surface-functionalization of magnetite nanoparticles (NPs) with poly(amidehydroxyurethane) (PAmHU) is presented. Transmission Electron Microscopy shows the formation of NPs PAmHU cluster systems with individual NPs ranging in size from 6 to 42 nm. Electron Spectroscopy for Chemical Analysis, Electron Paramagnetic Resonance measurements, and X-ray Diffraction show that the electrochemically synthesized product contains NPs formed by a core-coating polymer system with an inner-core consisting of magnetite entities with crystallites dimensions within 6 to 11 nm. The resulting functionalized NPs are water-soluble and stable for months.     

Study on morphology and photoluminescence of Au/SiO2 nanocomposite films

Au/SiO₂ nanocomposite films were fabricated on Si (111) substrates by radio frequency (RF) magnetron sputtering technique and annealing at different temperature for 20 min (mode A) and at 1000 °C for different annealing time (mode B). The nanocomposite films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoluminescence (PL). SEM results demonstrate that the size of Au crystallites in mode A first increases and then decreases, on increasing annealing temperature, according to the results of XRD spectra. Analysis of PL spectra in mode B shows that the intensity of the emission peak at 440 nm and 523 nm early increases and late decreases, with increasing annealing time at 1000 °C. The origin of the emission peak at around 440 nm was related to the size and quantity of Au particles and one of the emission peak at around 523 nm was related to the nanostructure of films in agreement with SEM imagines. Experimental results indicated that morphology, microstructure and luminescence of Au/SiO₂ nanocomposite films showed close affinity with annealing temperature and annealing time.     

Photochemical synthesis of copper nanoparticles incorporated in poly(vinyl pyrrolidone)

The effect of the presence of poly(vinyl pyrrolidone) (PVP) on the copper nanoparticle formation, obtained by UV irradiation of ethanol solution of Cu(acac)₂ (acac = 2,4-pentanedionato), was investigated. At 254 nm, in conditions of light completely absorbed by complex, the PVP exhibited protective and stabilizing effects, as shown by the formation of a colloidal copper solution and by a block of the heterogeneous process, which leads to thin film formation on the quartz walls. The colloidal solution was tested for several months by plasmon position and it was found that it remained unaltered in inert atmosphere, but returned to the starting complex on contact with air. The PVP ability to control the particle size was investigated by carrying out photoreduction sensitized by Hacac at 254 and 300 nm, in the presence of PVP concentration varying from 0 to 0.2 M. In this range it was possible to obtain copper nanoparticles of dimensions decreasing from 30 to 4 nm. Besides this, the PVP (0.005–0.05 M) role as sensitizer was investigated by irradiating solutions of Cu(acac)₂ at 300 nm which is an inactive wavelength for copper reduction by direct light absorption. It was found that the PVP was an efficient sensitizer of the copper photoreduction. The nanoparticles were characterized by plasmon band, Trasmission Electron Microscope (TEM) as well as Dynamic Light Scattering (DSL) analysis. The overall results evidence the advantages of the PVP use in the nanoparticle copper formation through the photochemical technique such as the exclusive formation of colloidal copper, their size control, stable colloidal solution and complete return to the starting complex.     

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．     

Synthesis of ZnO nanowires on aluminum flake by aqueous method

ZnO nanowires are grown on aluminum flake at low temperature by using a simple aqueous solution method. X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscope (TEM) are applied to determine the as-grown ZnO nanowires morphology and crystal structures. The results show that the ZnO nanowires have wurtzite structure, and the diameter and length of the nanowire are 30 nm and more than 1.5 μm, respectively. Photoluminescence spectroscopy (PL) and Raman spectrum reveal the nanowires have good optical properties with low tensile stress. Meanwhile, photoelectrochemical cell (PEC) study verifies that ZnO nanowires as photoanodes are relatively stable in the photo-oxidation process, which could be a promising technique for practical applications.     

Quantitative evaluation of process induced strain in MOS transistors by Convergent Beam Electron Diffraction

Convergent Beam Electron Diffraction (CBED) experiments and simulations associated with Finite Element calculations were performed in order to measure strain and stress in a complex device such as periodic MOS transistors with a spatial resolution of about 2 nm and a sensitivity that could reach 50 MPa. A lamella of a thickness of about 475 nm was extracted from the wafer with the transistors by Focus Ion Beam (FIB) and was observed in cross-section in a Transmission Electron Microscope (TEM). When approaching the transistors, the HOLZ lines of the CBED patterns acquired in the silicon substrate, become broader and broader. This HOLZ line broadening, which is due to the stress relaxation in the thin foil, was used to determine quantitatively the strain and stress in the lamella and then in the bulk device. We showed that this procedure could be applied to a complex device. Two parameters, the intrinsic material strains – or equivalently the intrinsic material stresses – in the nickel silicide (NiSi) and nitride (Si₃N₄) layers on the top of the transistors gate, were successfully fitted by trial and error, in the procedure.     

Sol–gel synthesis of pure nano sized β-tricalcium phosphate crystalline powders

β-Tricalcium phosphate (β-TCP) nano powders (80 nm) were synthesized using a simple sol–gel route with calcium nitrate and potassium dihydrogenphosphate as calcium and phosphorus precursors, respectively. Double distilled water was used as a diluting media for β-TCP sol preparation and ammonia was used to adjust the pH. After aging, the β-TCP gel was dried at 40 °C and calcined to different temperatures ranging from 200 to 800 °C. The dried and calcined powders were characterized for phase composition using X-ray diffractrometry (XRD) and Fourier transform-infrared spectroscopy (FT-IR). The particle size and morphology was studied using Transmission electron microscopy (TEM). Calcination revealed that with increase in temperature, both the crystallinity and crystallite size of β-TCP particles increased. Particle size distribution analysis of the calcined β-TCP at 800 °C showed a narrow skewed distribution plot centered between 70 and 80 nm. This value was in closed agreement with particle size values obtained from XRD analysis (83 ± 6 nm). The present study showed that narrowly distributed, high crystalline, pure β-TCP could be obtained using this simple technique for biomedical applications.     

Analysis of chemical property for Cu–Cr complex surface by laser irradiation with different wavelength and laser mode

Modification of the metal complexes by the laser irradiation with different wavelength and beam quality is investigated. After irradiation, the structure of macromolecular metal complexes are changed, and the reducing metal crystal nucleus emerges.. In this paper, the surface of the metal complexes is irradiated by laser scanning with wavelengths of 532 nm, 1064 nm and 10.6 μm.The 1064nm laser performs the most favorably by using Scanning Electron Microscope and X-ray Photoelectron Spectroscopy. Because the change of chemical composition percentage and variation of metal chemical valence state is most evident. Furthermore, mode selection of laser cavity by adding a pinhole aperture further improves the surface topography, fineness of modification and reducing ability. The appropriate wavelength and mode selection should be utilized together with other influencing laser parameters to achieve the most favorable consequence of metal complexes surface modification.     

Photoconducting nanocrystalline lead sulphide thin films obtained by chemical bath deposition

A chemical bath deposition method of preparing photoconducting nanocrystalline lead sulphide (PbS) thin films at room temperature (RT) is described. The aqueous bath of lead acetate, thiourea, and ammonium hydroxide produce films of about 100?nm thicknesses in 45?minutes. X-ray diffraction (XRD) studies show that these films are nanocrystalline cubic PbS with 10?nm crystallite size. Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM) revealed that the films consist of spherical grains of sizes 100 to 200?nm. The transmission spectra of the films show onset of absorption edge around 850?nm and the bandgap is around 1.65?eV. The films are p-type with dark conductivity of 2.5×10^?3?S/cm and mobility of 0.07?cm²/V?s. The photosensitivity is 6–7 for an illumination of 80?mW/cm² from a halogen lamp (50?W, 12?V). Transient photoconductivity measurements reveal short and long life times of minority carriers. Thermoelectric and photothermoelectric studies show that photoconductivity in these films is mainly due to photogenerated majority carriers.     

氮自掺杂Ta_2O_5微球制备及其光催化性能研究

我们采用水热法合成了具有可见光吸收的非金属自掺杂N-Ta_2O_5多孔微球光催化剂.并通过X射线粉末衍射仪(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、紫外可见分光光度计(UV-vis)等多种表征手段对自掺杂N-Ta_2O_5的晶体结构、形貌、组分等进行了测试分析.XRD结果表明,Ta N可以在HF溶液中完全氧化为Ta_2O_5,N掺杂可以通过N与O原子的轨道杂化使Ta_2O_5的带隙从4.0 eV降低为2.2 eV,从而增强其可见光吸收.高催化活性的N-Ta_2O_5可通过调控其结晶度来实现.     

Peroxide-based route assisted with inverse microemulsion process to well-dispersed Bi<Subscript>4</Subscript>Ti<Subscript>3</Subscript>O<Subscript>12</Subscript> nanocrystals

Well-dispersed bismuth titanate (BIT) nanocrystals with an average size ranged from 3 to 60 nm were synthesized via a peroxide-based route assisted with an inverse microemulsion process. The crystallite size and lattice parameter of BIT upon variable-temperature were determined by X-ray diffraction (XRD). The particle size was confirmed by transmission electron microscopy (TEM). Thermal decomposition behaviour of Ti-peroxy and BIT gel and crystallization kinetics of BIT nanocrystals were investigated by differential scanning calorimetry/thermogravimetry (DSC/TG) and Fourier-Transform infrared spectroscopy (FTIR). Analysis of nonisothermal DSC data yielded a value of 220.84 ± 2.73 KJ/mol and 2.25 ± 0.26 for the activation energy of crystallization (E _a) and the Avrami exponent (n), respectively.