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In this study, new types of hybrid gold poly(methyl methacrylate) (PMMA) nanomaterials are synthesized. Both PMMA spheres coated with gold nanoparticles and gold nanoparticles coated with PMMA can be synthesized using different ratios of HAuCl 4 and MMA precursors, by exposing the mixtures to hard X-ray synchrotron radiation without the use of a reducing agent. According to the photochemical mechanism, gold nanoparticles will precipitate from a solution of HAuCl 4 on exposure to synchrotron radiation, followed by the synthesis of PMMA by the polymerization of MMA monomers. These reactions can result in the formation of two different types of new hybrid nanomaterials. When a 1:1 volume ratio of HAuCl 4 to MMA is used, we obtain PMMA spheres coated with gold nanoparticles. When a 10:1 ratio of HAuCl 4 and MMA is used, we obtain gold nanoparticles coated with PMMA. The hybrid gold/PMMA nanostructures are characterized by transmission electron microscopy, elemental analysis, dynamic-light scattering analysis, gel permeation chromatography and Raman spectroscopy. The hybrid nanomaterials have potential application in the fields of biosensors and drug delivery.

In the present study, pure TiO2 and hybrid TiO2/CNTs nanomaterials are prepared by sol gel technique. Post heat treatment is performed at 600, 800, and 1000 degrees C, respectively. The structural characterizations are performed by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction and synchrotron X-ray absorption spectroscopy techniques. Experimental results show that anatase to rutile transformation can be observed for pure TiO2 nanomaterials after heat treatment at 800 degrees C. The anatase to rutile transformation is inhibited by carbon nanotubes, and therefore only anatase phases for TiO2 nanomaterials can be observed in the hybrid nanomaterials. The 600 degrees C hybrid nanomaterials show a microstructure with CNTs covered by continuous TiO2 films of numerous small nanoparticles. After applying heat treatment on the hybrid nanomaterials at 1000 degrees C, only TiO2 nanoparticles adhere individually to the uncovered CNTs. Though all hybrid nanomaterials exhibit anatase TiO2, synchrotron X-ray absorption spectra investigations reveal that hybrid TiO2/CNTs exhibit different electronic properties as compared to those of pure TiO2 nanomaterials.

It is known that palladium-based catalysts are initially very active in direct formic acid oxidation but they suffer from fast deactivation caused by a strongly adsorbed CO intermediate. Reactivation of the catalysts involving application of anodic potential may cause palladium dissolution. The aim of the present study is to increase the stability and performance of palladium-based catalysts in direct formic acid fuel cells (DFAFCs). Preparation and characterization of palladium/multiwalled carbon nanotubes (Pd/MWCNTs) and towards formic acid oxidation via different treatments are described. The catalysts were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry (CV). It was shown that the Pd and Pd–Au MWCNTs supported catalysts after reduction in H2–Ar at 200 °C (R200 treatment) were highly active in formic acid electro-oxidation, whereas the catalysts after heating in argon at 250 °C (C250 treatment) were inactive. The catalysts after hydrogen treatment have smaller metal particles and better contact with MWCNTs support. CV, simulating reactivation of the catalysts, showed that the Pd catalyst suffers from severe Pd dissolution, whereas for the Pd–Au selective leaching of Pd is considerably slower.

Novel multi-wall carbon nanotubes (MWCNTs) supported Pd–Au catalyst for electrooxidation of formic acid was prepared and compared with a similarly prepared Pd/MWCNTs and with a commercial Pt–Ru/Vulcan catalyst. The catalysts were prepared by a two-stage polyol method, followed by H2–Ar annealing and were characterised by using X-ray diffraction, FE-TEM and EDX. Cyclic voltammetry (CV) was used to test their catalytic activity towards formic acid electrooxidation and accessible metal surface in the catalyst layer. In the case of the precursor of Pd–Au/MWCNTs catalyst (before H2–Ar annealing), subsequent deposition of Pd and Au led to a material of the core-shell structure, catalytically inactive. Annealing of the core shell Pd–Au/MWCNTs precursor in H2–Ar resulted in the formation of the novel Pd–Au/MWCNTs catalyst. A highly dispersed Pd–Au solid solution (average XRD particle size 4.8 nm) is formed, and the novel catalyst is more active than the Pd/MWCNTs one. Both the Pd–Au/MWCNTs and the Pd/MWCNTs catalysts turned out to be more active than a commercial, highly dispersed Pt–Ru/Vulcan catalyst.

Externally applied magnetic fields have been used in this study to fabricate bamboo-like iron nanowires with or without a layer of Poly(methyl methacrylate) (PMMA). The hybrid PMMA/Fe nanowires were synthesized via hard X-ray synchrotron radiation polymerization with various treatment parameters. The results of XRD show that an oxide layer formed on the surface of the iron nanowires. The Fe2O3 and Fe3O4 phases coexist in the iron nanowires without X-ray irradiation. After X-ray irradiation, the Fe2O3 phase transformed into Fe3O4, which stabilized the iron nanowires. The results of XAS proved this phase transformation. TGA analysis confirmed the thermal properties and solid contents in these specimens. Their ferromagnetic behaviors were examined by magnetic hysteresis measurement, which indicated that the magnetic and structural properties of the nanowires can be manipulated by irradiation treatment. This may lead to a novel synthesis for iron nanowires that can be used in high thermal efficiency hyperthermia therapy.

An attempt to explain the origin of the vivid red color in precious pink and red corals was undertaken. Raman and IR spectroscopies were applied to characterize white, pink and red corals. The position of the Raman signal near 1500 cm −1 of some corals and pearls was associated by several authors with the presence of the mixture of all-trans-polyenic pigments, containing 6 – 16 conjugated C C bonds or β-carotenoids. This hypothesis was examined theoretically by performing extensive B3LYP-DFT calculations of vibrational spectra of the model polyenic compounds. The B3LYP/6-311++G ∗∗ predicted positions of the dominating Raman mode depend on the number of C Cu nits (Cn parameter) and can be accurately predicted for larger systems from a simple nonlinear fit. The DFT-predicted Raman activities of these modes are extremely sensitive to Cn ,a nd sharply increase with the number of double bonds. This implies a presence of only – two to three polyenes differing slightly in the number of C C units as the source of color in pink and red corals. Copyright c � 2009 John Wiley & Sons, Ltd. Supporting information may be found in the online version of this article.

Au/TiO2 nanocomposite particles were synthesized by a method based on intense X-ray irradiation without adding any reducing agent or stabilizer. The nanocomposite exhibits promising photocatalytic and biological properties at physiologically relevant concentration ([Au] = 0.028 mM, [TiO2] = 0.5 mM). The structure and photocatalysis were examined by X-ray diffraction, electron microscopy and ultraviolet-visible spectroscopy demonstrating that gold nanoparticles of 2-5 nm size were successfully deposited on TiO2 nanoparticle surfaces. The nanocomposite exhibited good colloidal stability within a typical cellular environment and was nontoxic to cancer cell according to evaluations under controlled conditions. The Au/TiO2 nanoparticles were also found to enhance the photocatalytic efficiency of UV radiation and even more that of X-ray radiation. In vitro studies indicated that the cell-killing effect under X-ray irradiation is more pronounced with the addition of Au/TiO2 nanoparticles than of bare TiO2 nanoparticles. (C) 2009 Elsevier B.V. All rights reserved.

Colloidal Ag nanoparticles were formed by X-ray irradiation in the presence of a polymer. This new synthesis method is simple, rapid and leads to a high production yield. Compared to the citrate-reduced Ag colloidal, polymer-protected Ag nanoparticles are smaller in size and more stable—and therefore suitable for biomedical application—as verified by TEM observation, XAFS measurement and optical characterization. Ag nanoparticles so produced were also visualized in solution and in real time by a visible light microscope based on dark field light scattering. The color-derived size and distribution of Ag nanoparticles correlates well with the hydrodynamic size data.

In recent years, research into three-dimensional (3-D) scaffolds for tissue engineering has become an important topic. To avoid biological rejection, there are many biocompatible materials being developed for in vitro cultivation of autologous cells for implantation into the human body. The 3-D structures of scaffolds are not easily observed using traditional optical or electron microscopes, which only allow examination of the surfaces of samples or ultra thin films, and often require complicated pre-treating processes. The high-brilliance synchrotron radiation (SR) hard X-ray is an emerging technique to acquire tomography. This study involves the successful reconstruction of 3-D images and the animation of the structure of a collagen scaffold. The images were obtained using synchrotron radiation hard X-ray images, which eliminates the need for embedding and microtoming. SR hard X-ray imaging is a non-destructive technique, which has demonstrated a high spatial resolution and transmission, enabling the morphology of osteoblasts adhered on the inner surfaces of the collagen scaffolds to be captured. It is a convenient facility to obtain 3-D tomography images for biomaterial studies. This is the first study to observe the 3-D structures of collagen scaffolds and aquire detailed images of osteoblast attachment on the scaffold, by utilization of third-generation SR hard X-ray radiography.

An in situ synthesis of ZnS and CdS quantum dots (QDs) in an aqueous solution of sodium hyaluronate (Hyal) produced foils emitting light on excitation with a UV light. The wavelength of emission was only slightly QDs size and more QDs concentration dependent and reached up to ∼320 nm in the case of ZnS and ∼400–450 nm in the case of CdS. Nanoparticles remained as non-agglomerated 10–20 nm nanoclusters. CdS/Hyal and ZnS/Hyal—QDs biocomposites were characterized using photoluminescence (PL), IR spectrometric techniques, and Transmission Electron Microscopy (TEM). The absolute molecular weights, radii of gyration, R g , and thermodynamic properties of the obtained foils are given. Electric resistivity studies performed for the hyaluronic foil in the 100–1000 V range have revealed that the hyaluronate foil has very weak conducting properties and QDs only insignificantly affect those properties as QDs practically did not interact with the foil. Size exclusion chromatography showed a decrease in the molecular weight of the hyaluronate after generation of QDs in its solution, particularly in the lower molecular fraction of the hyaluronate. The generation of CdS QDs was more destructive for the polysaccharide matrix.

In the present study, hybrid Pt/TiO 2 /MWCNTs nanomaterials are prepared successfully by a combined sol–gel and polyol process. The as-prepared nanomaterials are characterized by X-ray diffraction, high resolution transmission electron microscopy, and thermogravimetry analysis. In addition, its catalytic performance by converting CO into CO 2 is also evaluated. Experimental results show that the hybrid Pt/TiO 2 /MWCNTs nanomaterials exhibit a mixture of anatase TiO 2 and Pt phases. Multi-wall carbon nanotubes serve as an excellent supporting material where anatase TiO 2 nanoparticles are decorated with well-distributed Pt nanoparticles. Excellent catalytic performance can be revealed for the hybrid Pt/TiO 2 /MWCNTs nanomaterials. When compared with its Pt/TiO 2 counterparts where ∼ 100% CO conversion occurred at 150 °C, almost 100% conversion of CO into CO 2 can be observed at a temperature ranged from 30 °C to 100 °C.

The aim of this research is to investigate the method of white X-ray irradiation (WXI) for forming nano particles or wires mostly inside multi-walled carbon nanotubes (MWCNTs). WXI approach which uses the energy of light to react with MWCNTs in aqueous solution has not yet been found. This study is mainly focusing on white X-ray irradiation technique which illustrates MWCNTs can be used as template for self-assembled nanowires. WXI synthesis technique is compared with the traditional method of heat treatments for various structures of nano hybrid materials. The research indicates that the traditional heat treatment results in nano particles being on the surfaces of MWCNTs; while the WXI keeps them inside MWCNTs. Accordingly, a model of light-heat transformation for MWCNTs is proposed to explain the mechanism of reaction inside MWCNTs. It is also found that the approach of WXI can fill nanoparticles inside MWCNTs in a comparatively shorter time.

In the present study, Ti 50 Cu 28 Ni 15 Sn 7 (at.%) metallic glass and its composite powders reinforced with 4-12 vol.% of added SiC were successfully prepared by mechanical alloying. In the ball-milled composites, an amorphous matrix with a homogeneous dispersion of SiC particles was developed. The metallic glass composite powders were found to exhibit a large supercooled liquid region before crystallization. The presence of SiC particles did not change the glass-formation ability of the amorphous Ti 50 Cu 28 Ni 15 Sn 7 powders. Consolidation of the as-milled Ti 50 Cu 28 Ni 15 Sn 7 composite powders was performed at a temperature slightly higher than the glass-transition temperature under a pressure of ∼1.2 GPa; using this method, the bulk metallic glass composite discs were prepared successfully. However, partial crystallization of the amorphous matrix during the hot-pressing process was noticed. The fracture strength of consolidated composite compacts was increased with SiC additions. The pre-existing particle boundaries may serve as the crack initiation sites which resulted in the brittle failure of the Ti 50 Cu 28 Ni 15 Sn 7 BMG composites.

Formation of surface and inclusion complexes of single-walled carbon nanotubes (SWCNT) with dextrans of M w 6000 to 2 000 000 was proven spectrally, rheologically, and calorimetrically. Band shifts in the Raman spectra, increase in the viscosity of aqueous solutions of particular dextrans after admixture of SWCNT, and enthalpies of melting of those complexes were independent on molecular weight of dextrans. Computational simulations were performed using the HyperChem 7 and Gaussian 03 packages, starting from a model of single, short SWCNT and linear dextran chain made of 12, 18 or 24 β-D-glucose units. The simulation indicated that dextran chains composed of 12 or 18 β-D-glucose units only partly enveloped SWCNT and the intermolecular interactions in both terminals of the chains prevailed. The dextran containing 24 β-D-glucose units fully enveloped SWCNT. However, the role of SWCNT in the envelop formation was limited solely to its hydrophobic interactions with the central part of the dextran chain.

The corrosion behavior of mechanically alloyed Cu60Zr30Ti10 bulk metallic glass (BMG) in four different corrosive media was studied by the potentiodynamic method. The Cu60Zr30Ti10 BMG shows low corrosion current density and uniform corrosion in 1N H2SO4, NaOH and HNO3 solutions. The Cu60Zr30Ti10 BMG specimen (consolidated at 746K under 1.2GPa) specimen exhibits most corrosion resistance in 1N H2SO4. The formation of the oxide films and the nucleation and growth of pitting will be discussed in light of microstructural investigations.

Purification of multi-wall carbon nanotubes (MWCNTs) from the iron catalyst and amorphous carbon and associated with that process, their oxidation with conc. HNO 3 over 100 °C on sonication to carboxylated MWCNTs (CMWCNTs) is presented. A novel way of decoration of CMWCNTs with ZnO and ZnS quantum dots (QDs) is proposed. It involves the use of corresponding ammonium zincates. CNT–COO–Zn–X where X = OH and SH, respectively, provided nucleation for the QDs growth. That approach does not require any non-covalent mediation from either inorganic or organic carriers.

In the present study, amorphous Ni60Nb20Zr20 and Ti50Cu28Ni15Sn7 alloy powders were synthesized separately using a mechanical alloying (MA) technique. The dual-amorphous-phased (Ti50Cu28Ni15Sn7)100−x(Ni60Nb20Zr20)x (x = 0, 10, 20, and 30 vol%) powders were prepared by mixing the corresponding amorphous powders. The dual-amorphous-phased powders were then consolidated into bulk amorphous/amorphous composite (BA/AC) alloy discs. The amorphization status of as-prepared powders and bulk BA/AC composite discs was confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The microstructure of the BA/AC discs showed that the Ni60Nb20Zr20 phase is distributed homogeneously within the Ti50Cu28Ni15Sn7 matrix. The (Ti50Cu28Ni15Sn7)70(Ni60Nb20Zr20)30 BA/AC disc exhibited a relative density of 96.6% and its Vickers microhardness was 726 kg/mm2.

Ultrasonic spray pyrolysis of acetate-based precursors with precisely measured precursor drop size was employed to produce ZrO2 and CeO2 particles. A bimodal size distribution of the product particles indicates a significant influence of the gas-to-particle conversion mechanism in addition to the conventionally accepted one-particle-per-drop mechanism. Due to the differences in solubility of the precursors, ZrO2 particles are spherical in shape and smooth on their surfaces while the CeO2 particles are bowl-like in shape with uneven surfaces. Spherical and monodispersed particles with a peak diameter

The fabrication of gold Fresnel zone plates, by a combination of e-beam lithography and electrodeposition, with a 30 nm outermost zone width and a 450 nm-thick structure is described. The e-beam lithography process was implemented with a careful evaluation of applied dosage, tests of different bake-out temperatures and durations for the photoresist, and the use of a developer without methylisobutylketone. Electrodeposition with a pulsed current mode and with a specially designed apparatus produced the desired high-aspect-ratio nanostructures. The fabricated zone plates were examined by electron microscopy and their performances were assessed using a transmission X-ray microscope. The results specifically demonstrated an image resolution of 40 nm.

Nanocrystalline manganese oxide powders were prepared by spray pyrolysis (SP) from manganese acetate solution at 400 °C. The as-obtained powders were subsequently coated onto graphite substrates via an electrophoretic deposition technique (EPD). The as-prepared powders were examined by transmission electron microscopy (TEM), X-ray diffractometry (XRD), synchrotron X-ray absorption spectroscopy (XAS); the coatings were further examined by cycling voltammetry (CV). Experimental results showed that manganese oxide powders prepared at 400 °C were hollow spherical particles with fractured shells and possessed high surface area. CV examination showed that the as-deposited coatings also exhibited the highest specific capacitance of 275 F/g. After hundreds of CV cycles, the specific capacitance decreased to 234 F/g, which was still comparable to values reported in the literature. Structural investigation by TEM and XRD revealed that the as-deposited coatings exhibited Mn 3 O 4 phase with amorphous-like structure. While synchrotron XAS results showed that the manganese had a valence of + 2.67, it was transited into tetravalent manganese after cyclic voltammetry.

Reductant, stabilizer-free colloidal gold solutions were fabricated by a new room-temperature synchrotron X-ray irradiation method. The influence of process parameters such as the pH value and the exposure time on the structure of gold nanoparticles was investigated. The mechanisms underlying the X-ray-triggered reduction of gold ions and the formation of gold clusters are discussed in detail. The X-ray irradiation derived highly concentrated gold nanoparticles are readily to be re-dispersed and possess suitable colloidal stability within cellular environment. The characterization included a study of the possible cytotoxicity for the EMT-6 tumor cell line: the negative results indicate that the gold clusters produced with our approach are biocompatible.

In the present study, Ti50Cu28Ni15Sn7 metallic glass and its composite powders reinforced with 4~12 vol% of SiC additions were successfully prepared by mechanical alloying. The as-milled Ti50Cu28Ni15Sn7 and composite powders were then consolidated by vacuum hot pressing into disc compacts with a 10 mm diameter and thickness of 2 mm. The structure of the as-milled powders and consolidated compacts was characterized by X-ray diffraction. While the thermal stability was examined by differential scanning calorimeter. In addition, the mechanical property of the consolidated bulk metallic glass and its composite was evaluated by Vickers microhardness tests. In the ball-milled composites, initial SiC particles were homogeneously dispersed in the Ti-based alloy glassy matrix. The presence of SiC particles did not dramatically change the thermal stability of Ti50Cu28Ni15Sn7 glassy powders. BMG composite with submicron SiC particles homogeneously embedded in a highly dense nanocrystalline/amorphous matrix was successfully prepared. A significant hardness increase with SiC additions was noticed for consolidated composite compacts.

The TFTs array fabrication process for large-area TFT-LCD has been continuously developed for simplifying processing steps, improving performance and reducing cost in the process of mass production. In this study, the hydrogenated amorphous silicon (a-Si:H) TFTs with low resistivity electrodes , silver thin films, were prepared by using the selective deposition method that combined lift-off and electroless plated processes. This developed process can direct pattern the electrode of transistor devices without the etching process and provide ease processing steps. The as-deposited Ag films were annealed at 200 oC for 10 minutes under N2 atmosphere. The results shows that the adhesion properties can be enhanced and the resistivity has been improved from 6.0 μ,-cm, significantly decrease by 35%, of as-deposited Ag films by annealed. The thickness of Ag thin film is about 100 nm and the r. m. s roughness value is 1.54 nm. The a-Si:H TFT with Ag thin films as source and drain electrodes had a field effect mobility of 0.18 cm2/Vs, a threshold voltage of 2.65 V, and an on/off ratio of 3×104.

Nanocrystalline iron oxide powders were prepared by an inert gas condensation technique under various oxygen partial pressures. The as-prepared nanocrystalline iron oxide powders were further modified by electroless nickel plating. The as-prepared and modified nanocrystalline powders were characterized by X-ray diffraction, transmission electron microscopy, and synchrotron X-ray absorption techniques. In addition, magnetic properties of the iron oxide nanoparticles before and after electroless nickel plating were evaluated by vibrating sample magnetometer. The experimental results show that the as-prepared nanocrystalline iron oxide powders exhibited a mixture of iron and γ-Fe2O3 phases. TEM observations revealed that oxidation started from the surface of the gas-condensed iron nanoparticles. The amount of iron oxide increased with increasing oxygen partial pressure and was confirmed by synchrotron x-ray absorption examination. A decrease in saturated magnetization and coercivity of the nanocrystalline iron oxide powders was observed after electroless nickel plating.

Multi-wall carbon nanotubes (MWCNTs) were used as a support for the deposition of highly dispersed platinum. After characterization by several physical techniques, the catalyst was studied in reactions for: hydrodechlorination of carbon tetrachloride and the hydrodechlorination of dichlorodifluoromethane. For the first reaction Pt/MWCNTs were very effective catalysts in terms of both the overall activity and the selectivity to CHCl3; both quantities appeared high and stable. For CCl2F2 hydrodechlorination the catalyst was rather moderate, although very stable, activity and product selectivities were established at a constant level in a relatively short time-on-stream. The MWCNTs-supported Pt particles do not undergo great changes during the reactions, i.e. neither substantial metal sintering occurred nor extensive surface carbonization/chloriding took place.

Amorphous Ti50Cu28Ni15Sn7 alloy powders were synthesized by a mechanical alloying (MA) technique. Differential scanning calorimetry (DSC) results showed that, after 7 hours of exposure to the milling process, amorphous Ti50Cu28Ni15Sn7 alloy powders exhibit a wide supercooled liquid region of 61 K. Consolidation of amorphous powders were performed at a temperature slightly higher than the glass transition temperature under a pressure of ∼1.2 GPa, and bulk metallic glass (BMG) discs can be prepared successfully. However, we noticed partial crystallization during the hot pressing process and were not able to achieve full densification of BMG. The Vickers microhardness of Ti50Cu28Ni15Sn7 BMG was 634 kg/mm2, and the trace of the indentation revealed that pre-existing particle boundaries or interfaces between nanocrystals and amorphous matrix may serve as the crack initiation sites. Thus, typical brittle failure of Ti50Cu28Ni15Sn7 BMG was observed and resulted in relatively low fracture stress compared to that estimated by the microhardness.

A nanohybrid sensor of nanosized TiO2-coated carbon black particles, prepared by sol–gel technology for the detection of NO2 gas, has been developed. The response of the electric resistance of the hybrid sensor to NO2 concentration is investigated, showing that the sensitivity of the hybrid sensor is raised as certain ratio of the TiO2 content in the sensor. Easy and cheap to fabricate, the hybrid TiO2/carbon black promises to be a practical sensor for detecting NO2 gas.

Gold nanoparticles decorating the surface of multiwalled carbon nanotubes (MWCNTs) are prepared by photochemical reduction. The gold clusters form different interesting geometrical faceted shapes in accordance to time duration of synchrotron X-ray irradiation. The shape of nanogold could be spherical, rod-like, or triangular. Carbon nanotubes serve as optimal templates for the heterogeneous nucleation of gold nanocrystals. These nanocrystal structures are characterized by transmission electron microscope (TEM) and element analysis by energy dispersive spectroscopy (EDS).

The purpose of this study is fabrication and characterization of silver nanofluid by the submerged arc nanoparticle synthesis system (SANSS). The silver metal electrodes under the electrical discharge will melt and evaporate rapidly and condense to form the nanoparticles in the lower temperature dielectric liquid and produce the suspended nanoparticle. The results showed that the spherical nanosilver particle formed in the ethylene glycol and the mean particle size is about 12.5 nm. The prepared silver nanofluid was irradiated under the 410 nm visible light, electrons could be excited from the valence band to the conduction band. The silver nanofluid more closely resembles Newtonian fluids.

Gold nanoparticles have been attracting attention due to their extensive application in chemistry, physics, material science, electronics, catalysis and bionanotechnology. Synthesis of gold nanoparticles often involves toxic and expensive physical-chemistry methods. Preparation of gold nanoparticles by arc discharge in water is proposed for the first time. Fabrication of gold nanostructures in deionized water has been successfully established. The evidence of gold particles’ light absorbance reveals a unique surface plasmon resonance for Au nanoparticles suspended in deionized water. Gold nanostructures uniformly dispersed in water, their UV–Vis absorption and crystalline size are shown. Our experimental results demonstrate that fabrication of gold nanoparticles by arc discharge in water is an alternative, cheap, effective and environmentally friendly method.

Agarose, -, K-, and λ-carrageenans, and xanthan gum in aqueous solutions interacted with single-walled carbon nanotubes (SWCNTs) as proven by their wetting in solution and by the microRaman spectroscopy, rheological studies, and differential scanning calorimetry. The investigations provided evidence that the effect of complexation of polysaccharides was independent of the possibility of the formation of helical complexes. Complexation involved, to a certain extent, interactions between hydrophobic surface of nanotubes and hydrophobic sides of the saccharide units of polysaccharides. However, clathration of nanotubes in the polysaccharide matrices was also essential. Formation of the clathrate cages involved intra- and intermolecular hydrogen bonds within polysaccharides.

In the present study, amorphous Mg 49 Y 15 Cu 36 and Ti 50 Cu 28 Ni 15 Sn 7 alloy powders were synthesized separately by using a mechanical alloying technique. The dual-phase (Mg 49 Y 15 Cu 36 ) 100-x (Ti 50 Cu 28 Ni 15 Sn 7 ), (x = 0, 10, 20, 30, 40, and 50vol%) powders were prepared by mixing the corresponding amorphous powders. The amorphous dual-phase powders were then consolidated into bulk metallic glass (BMG) discs. The amorphization status of as-prepared powders and BMG discs was confirmed by X-ray diffraction and by using a differential scanning calorimeter. The microstructure of the BMG discs showed that the Ti 50 Cu 28 Ni 15 Sn 7 phase is distributed homogeneously within the Mg 49 Y 15 Cu 36 matrix. The (Mg 49 Y 15 Cu 36 ) 50 (Ti 50 Cu 28 Ni 15 Sn 7 ) 50 BMG disc exhibited a relative density of 97.2% and its Vickers microhardness was 526±20 kg/mm 2 .

Novel metal catalysts are easily poisoned by CO adsorption or leaching in oxidation of formic acid that leads to decrease the performances of catalyst. To increase the catalyst activity and poison tolerance in fuel cells, novel metal nanoparticles are usually supported on modified support materials to enhance its performance. In this study, TiO2/MWCNTs are synthesized by sol-gel method. Also, ammonium is used to dope nitrogen into TiO2 to modify its electrical and chemical property. MWCNTs, TiO2/MWCNTs and N-doped TiO2/MWCNTs are three supporters using in this study to examine the effects of supporters on the electrocatalytic performance of Pd and AuPd catalysts. The synthesized metal nanoparticles are uniformly dispersed on the surfaces of MWCNTs, TiO2 and N-doped TiO2 modified MWCNTs. The electrochemical analysis illustrate that Pd/N-doped TiO2/MWCNTs (molar ratio of NH4OH:TiO2=4:1) catalyst exhibits higher activity and better stability than that of Pd/MWCNTs either/or Pd/TiO2/MWCNTs catalyst in formic acid electrooxidation. Same results are observed in AuPd series of catalyts. It indicates that suitable N-doping TiO2 improves dramatically on the performance of Pd or AuPd-based catalysts in electrochemical reaction. Thus, hybrid AuPd/N-doped TiO2/MWCNTs (molar ratio of NH4OH:TiO2=4:1) materials have potentially to be used in the direct formic acid fuel cells (DFAFCs) in the future. Keywords—Fuel cells, Formic Acid, Pd, AuPd, N-doped TiO2, catalyst, MWCNTs

We developed a novel approach to prepare Ni–Au composite nanoparticles using synchrotron radiation X-rays. Ni–Au particles dispersed in aqueous solutions were synthesized with two different irradiation strategies. The first is by exposing to X-rays a mixed electroless solution of Ni and Au at two different temperatures, trying to nucleate Ni nanoparticles homogeneously at room temperature and to deposit Au subsequently on them at the high temperature of 70 °C. The second strategy is to change the pH value of the mixed solution, directly leading to the formation of Ni–Au nanoparticles. In both cases, the Ni–Au composite nanoparticles were successfully formed, as confirmed by the observed ferromagnetic behavior and by the evolution of the Au surface plasmon resonance band.

This paper describes the instrumentation and analysis of the Vehicle suspension's electrical signals. It will measure the Vehicle suspensions' Vertical Displacement, Track Change, Camber Angle, Caster Angle Steer Angle and convert physical quantity into electrical signals in a various vehicle load change. With using electrical signals for computer control, the electrical controlled vehicle has brought great convenience, great safety and thoughtful kindness vehicle system in our daily life. It will measure the Vehicle suspensions' Vertical Displacement, Track Change, Camber Angle, Caster Angle Steer Angle and convert physical quantity into electrical signals in a various vehicle load change. The function of a suspension system in an automobile is to improve ride comfort and stability. Advances in electronic control technology, applied to the automobile, can improve those functions. The results show that the photocell can convert the electrical signals of suspension for peripheral communications link between the vehicle driving and the electronic control unit (ECU) employed for processing.

The behaviour of an elastomeric seal for vehicle brake Tandem master cylinder is measured and analyzed in temperature and brake fluids changed. Working conditions are simulated for different piston rod velocity and cylinder supply pressure, in temperature rising, brakefluid boundary and Nanoaluminum oxide brakefluid oxide brakefluid lubrication. The result shows that Nanoaluminum oxide brakefluid with its ball shape can highly reduce friction coefficient to avoid seal excessive wear and reduce slick slip in brake applications.

Most of the gases detecting metal oxide semiconductors are operated at temperatures above 250oC. It is not energy efficient for MOS gas sensors to operate at such high temperature. To solve this problem, research and investigations are trying to obtain new MOS sensing materials that can operate at ambient temperature. In this study, gas sensing materials consisting of MOS and carbon nanotubes (CNTs) are developed for detecting gases at lower temperature. The hybrid system, MWCNTs/TiO2, demonstrates the possibility of detecting the gases at ambient temperature with high energy efficiency.

The low-pressure control methods for an arc-submerged nanoparicle synthesis system (ASNSS) was proposed and developed for brake nanofluids. In the process, a copper bar is melted and vaporized in insulating liquid for core formation with crystallization suppressed to derive nanofluid that contains nanometer copper particles in DOT3 brake fluid. Two technical advances associated with nanoparticle synthesis were achieved. One is the novel pressure control technique developed for nanoparticle fabrication. The other is the verification that the constant low-operating pressure. Pressure operating plays important role in determining the characteristics of the prepared nanoparticles in brake fluids. From the experimental processes, pressure control of the ASNSS was identified as crucial to success of nanoparticles synthesis. To achieve the desired pressure control, a vacuum chamber was developed as a nanoparticle accumulator and low-pressure reservoir. The chamber was controlled by the proposed flow –valve feedback control system and integrated with the ASNSS. The pressure control equipment of the ASNSS was effectively developed to prepare desired copper-oxide brake nanofluids with well-controlled size.

This article presents the development of an automatic on-line measurement system for characterizing a nanoparticle manufacturing process known as Arc Spray Nanoparticle Synthesis System (ASNSS). The ASNSS has been developed to generate metal nanoparticles and to explore the optimum system parameters for producing the desired nanopowders. Preliminary experimental results indicate that the size of nanoparticles, widely ranging from 10nm to 300nm, is significantly affected by the process parameters such as operating pressure, temperature, electrical current and type of dielectric liquid used. The on-line measurement system was developed to provide an effective multi-solution for characterizing the nanoparticle synthesis process and for monitoring the manufacturing quality of the ASNSS. Experiments were conducted to identify the optimum sampling period and volume of the particle suspension for accurate sampling and data acquisition. Experimental results revealed that a sampling duration of 20 minutes and a dielectric volume of 40 c.c. can achieve effective data representation while maximizing the sampling efficiency.

This study proposes a new method: the combined arc-submerged nanoparticle synthesis system (ASNSS) for preparing TiO2 nanofluid. In addition to the influence of the various process variables such as breakdown voltage, peak current and dielectric liquid temperature on nanoparticles, this study will also discuss the photocatalytic activity of the prepared TiO2 nanoparticle suspension. To examine the photocatalytic activity of the TiO2, the photodecomposition of salicylic acid was carried out. Experimental results show that the proposed method can successfully prepare anatase TiO2 and this nanofluid can be stabilised for longer than six months. The rate constant of photocatalytic reaction of TiO2 nanoparticles for salicylic acid is 0·0035. Experimental results indicate that the TiO2 nanoparticle fluid possesses excellent photocatalytic activity in photodegradation of salicylic acid.

The optimal parameters are found for preparing nanofluid in our submerged arc nanoparticle synthesis system (SANSS) using a copper electrode. A suspended copper oxide nanofluid is thus produced at the current of 8.5–10 A, voltage of 220 V, pulse duration of 12 μs, and dielectric liquid temperature of 2°C. The CuO nanoparticle are characterized by transmission electron microscopy (TEM), field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), electron diffraction pattern (SAD) and electron spectroscopy for chemical analysis (ESCA). The equality volume spherical diameter of the obtained copper oxide particle is 49.1 nm, regular shape and narrow size distribution.

An effective procedure for obtaining healthy shoots from nodal segments of Scrophularia yoshimurae is described. Nodal segments cultured on Murashige and Skoog's (MS) basal medium supplemented with 1.0 mg L(-1) benzyladenine (BA) and 0.2 mg L(-1) alpha-naphthaleneacetic acid (NAA) induced multiple shoots in conical flasks that differed in the way they were closed and sealed. Hermitically sealed culture vessels resulted in high hyperhydricity/vitrification. High concentrations of ethylene and CO2 were found to accumulate in these vessels. The hyperhydricity of the shoot cultures could be decreased by progressively ventilating the vessels. Exchange of gases was achieved by removing the Parafilm sealing without affecting sterility. This reduced the hyperhydricity rate and gave a good recovery of vitrified shoots, but resulted in decreased proliferation and a dehydration of proliferating nodal segments and the culture medium. The best number of normal shoots was observed when the parafilm was removed for gaseous exchange after four weeks of culture incubation. The results show that hyperhydricity in shoot cultures of S. yoshimurae could be prevented by sufficient gas exchange during culture.

This article presents the development of an innovative approach using the vacuum submerged arc machining with aid of enhanced ultrasonic vibration to manufacture nanoparticles. The Arc Spray Nanoparticle Synthesis System (ASNSS) previously designed by the NTUT’s Nano Laboratory has been successfully developed to generate nanoparticles. In this proposed process, a titanium bar, as the electrode, is melted and vaporized in distilled water, used as an insulating liquid. Meanwhile, the ultrasonic vibration is applied to the electrode to remove the vaporized metal powders rapidly from the melting zone. The vaporized metal particles are then rapidly quenched by the designed cooling system, thus nanocrystalline particles nucleated and formed. This study discusses the the influence of the ultrasonic amplitude and various process variables such as pulse duration, peak current, and dielectric liquid temperature on TiO2nanoparticles suspension.

This article presents the development of an innovative technology to manufacture TiO2 nanoparticles. Manufacturing nanoparticles is considered as a crucial step towards product and process innovation. In our proposed process, a titanium rod, as the electrode, is melted and vaporised in deionised water, which is used as an insulating liquid. The vaporised metal particles are then rapidly quenched by the designed cooling system, and thus nanocrystalline powders are nucleated and formed. By implementing the system, we have successfully developed the processing equipment of the arc spray nanoparticle synthesis system (ASNSS). The experimental results indicate that uniformly distributed and well-controlled TiO2 nanoparticle size can be manufactured by ASNSS.

This study aims to investigate the use of a new nanoparticle preparation method, i.e., the arc spray nanoparticle synthesis system (ASNSS) combined with ultrasonic vibration and rotating electrode, to prepare TiO2 nanoparticle suspension. For the proposed new method of nanoparticle suspension preparation, this study has designed four different process modes of experimentation for comparison, in order to obtain suspended nanoparticles with smaller particle size and relatively good dispersion. This study discusses the process modes with different settings of variables including peak current, pulse duration, breakdown voltage, temperature of the dielectric fluid and amplitude of ultrasonic vibration, in order to determine the better conditions for the preparation of TiO2 nanoparticles suspension. The Transition Electron Microscope (TEM) image of the experiment result shows that TiO2 nanoparticles prepared by the ultrasonic vibration assisted vacuum arc spray process has an average particle size of less than 10 nm.

This article presents new findings regarding the effects of precursor drop size and precursor concentration on product particle size and morphology in ultrasonic spray pyrolysis. Large precursor drops (diameter > 30 μm) generated by ultrasonic atomization at 120 kHz yielded particles with holes due to high solvent evaporation rate, as predicted by the conventional one particle per drop mechanism. Precursor drops 6–9 μm in diameter, generated by an ultrasonic nebulizer at 1.65 MHz and 23.5 W electric drive power, yielded uniform spherical particles 90 nm in diameter with proper control of precursor concentration and residence time. Moreover, air-assisted ultrasonic spray pyrolysis at 120 kHz and 2.3 W yielded spherical particles about 70% of which were smaller than those produced by the ultrasonic spray pyrolysis of the 6–9 μm precursor drops, despite much larger precursor drop size (28 μm peak diameter versus 7 μm mean diameter). These particles are much smaller than predicted by the conventional one particle per drop mechanism, suggesting that a gas-to-particle conversion mechanism may also be involved in spray pyrolysis.

Tungsten oxide nanoparticles are prepared by evaporating and oxidizing the tungsten boat in helium and oxygen atmosphere and then quenched to the liquid nitrogen temperature. The as-prepared tungsten oxide nanoparticles are porous-free with uniform size. The morphology and particle size distribution of the as-prepared and after sinter treatments tungsten oxide nanoparticles are revealed by TEM and AFM. The long-range order of these nanoparticles can be examined by X-ray diffraction technique. The as-prepared nanoparticles exhibit a mixture structure of monoclinic and hexagonal crystals. Preliminary X-ray diffraction results indicate that the hexagonal structure is transformed to monoclinic structure after annealing to above 600°C. In order to better distinguish the structural properties of the tungsten oxide (WO3− x) nanoparticles before and after annealing, the X-ray absorption spectrum technique is utilized; thus, the detailed local atomic arrangement of oxygen and/or tungsten can be determined. According to the XAS result, the shape of the W L3-edge undergoes no considerable changes. This infers that structural transformation of tungsten oxide nanoparticle may be caused by the migration of oxygen after sintering. From the O K-edge of absorption spectrum, it suggests that a mixture phase structure is obtained when sintered below 300°C. And this result indicates that heat treatment to approximately 600°C produces a stable structure of a monoclinic crystal of WO3.

A new hybrid SWCNTs/SnO 2 gas sensor is developed by adding single-walled carbon nanotubes (SWCNTs) into a SnO 2 substrate. The fabrication involved heat-treating the SWCNTs/SnO 2 layer, which was fabricated by spin coating using an organometallic solution of dispersed with SWCNTs. The hybrid sensor is utilized to detect NO 2 concentrations in flowing air or N 2 , by considering alterations in electrical properties. The tests are performed at room temperature. Two hybrid sensors with different concentrations of SWCNTs are examined to elucidate the effect of a concentration of SWCNTs on the sensing properties of the sensors. A SnO 2 sensor without SWCNTs, a blank sample, is also examined for comparison. Comparative gas sensing results reveal that the prepared hybrid SWCNTs/SnO 2 sensors exhibit much higher sensing sensitivity and recovery property in detecting NO 2 gas at room temperature than the blank SnO 2 sensor. This finding shows that doping with SWCNTs improves the sensitivity of hybrid sensors. Microstructural observations revealed that SWCNT bundles are embedded in the SnO 2 matrix. Therefore, a model is presented to relate potential barriers to electronic conduction in the hybrid material. This model suggests that the high sensitivity is associated with the stretching of the depletion layers at the grain boundaries of SnO 2 and the SWCNTs/SnO 2 interfaces when detected gases are adsorbed.

Structure of nano-domes formed by Ga + ion irradiation with a focused ion beam (FIB) apparatus onto GaN nanowires (NWs) was examined with conventional transmission electron microscopy (CTEM), electron energy-loss spectroscopy (EELS) and energy-filtering TEM (EF-TEM). The nano-dome consisted of metallic gallium, covered by a GaN layer, the structure of which is amorphous or liquid. It is considered that the dome structure is formed by preferential displacement of lighter element (N) and agglomeration of heavier one (Ga). 1 MeV electron irradiation onto the sample pre-irradiated by Ga + ions at a dose below the threshold for the dome formation induced the N 2 bubble formation without segregating Ga atoms, which suggests the radiation-enhanced diffusion (RED) of heavy atoms plays an important role in the nano-dome formation.