Preparation of ZAO film by low-temperature hydrothermal approach and its electrical property

Al-doped ZnO (ZAO) films were successfully deposited on the surface of common glasses by using low-temperature hydrothermal approach. In the reaction solution, the molar ratio of Al3+ to Zn2+ was 1∶100, the annealing temperature and time were 200 ℃ and 2-6 h, respectively. The structure of the thin films was identified by X-ray diffraction (XRD), the surface morphology and thickness of the thin films were observed by scanning electron microscopy (SEM), and the electrical performance of the thin films was measured by four-point probes. It was shown that the films with an average particle size of 27.53 nm had a preferential orientation along (002), Al3+ had replaced the position of Zn2+ in the lattice without forming the Al2O3 phase and its thickness was 20-25 μm. With the increased annealing time, the intensity of diffraction peaks was decreased, the film exhibited irregular surface morphology gradually, and the resistivity of ZAO films was increased. The lowest resistivity obtained in this study was 3.45×10-5Ω·cm.

Studies on the Absorption of NO_2 by Polyethylene Glycol and the Oxidizing Properties of the Resulting Absorbent Product

PEG (Polyethylene glycol average molecular weight 300) is used as absorbent of NO2. The absorption efficiency is found to reach up to 97%. The absorbing product, PEG NO2, can be used to cleave benzyl ethers mildly and selectively to benzaldehyde and corresponding fatty alcohols, showing that PEG is a valuable oxidizing agent of benzyl ethers. As a carrier of NO2.PEG can be recovered and utilized repeatedly after the oxidation.

Electron Donating Property and Catalytic Activity ofPerovskite-type Mixed Oxides (ABO_3) Consisting of Rare Earth and 3d Transition Metals

The catalytic activity of Perovskite-type mixed oxides (LaCoO3, PrCoO3 and SmCoO3) for the reduction of cyclohexanone to cyclohexanol with 2-propanol (Meerwein-PonndorfVerley reduction) has been studied. The data have been correlated with the surface electron donor properties of these mixed oxides

Robust Particle Swarm Optimization Algorithm for Modeling the Effectof Oxides Thermal Properties on AMIG 304L Stainless Steel Welds

There are several advantages to the MIG(Metal Inert Gas)process,which explains its increased use in variouswelding sectors,such as automotive,marine,and construction.A variant of the MIG process,where the sameequipment is employed except for the deposition of a thin layer of flux before the welding operation,is the AMIG(Activated Metal Inert Gas)technique.This study focuses on investigating the impact of physical properties ofindividual metallic oxide fluxes for 304L stainless steel welding joint morphology and to what extent it can helpdetermine a relationship among weld depth penetration,the aspect ratio,and the input physical properties ofthe oxides.Five types of oxides,TiO_(2),SiO_(2),Fe_(2)O_(3),Cr_(2)O_(3),and Mn_(2)O_(3),are tested on butt joint design withoutpreparation of the edges.A robust algorithm based on the particle swarm optimization(PSO)technique is appliedto optimally tune the models’parameters,such as the quadratic error between the actual outputs(depth and aspectratio),and the error estimated by the models’outputs is minimized.The results showed that the proposed PSOmodel is first and foremost robust against uncertainties in measurement devices and modeling errors,and second,that it is capable of accurately representing and quantifying the weld depth penetration and the weld aspect ratioto the oxides’thermal properties.

Carbon monoxide oxidation on copper manganese oxides prepared by selective etching with ammonia

A series of copper manganese oxides were prepared using a selective etching technique with various amounts of ammonia added during the co-precipitation process. The effect of the ammonia etching on the structure and catalytic properties of the copper manganese oxides was investigated using elemental analysis, nitrogen physisorption, X-ray powder diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, H2 temperature-programmed reduc- tion, and Oz temperature-programmed desorption combined with catalytic oxidation of CO. It was found that ammonia can selectively remove copper species from the copper manganese oxides, which correspondingly generates more defects in these oxides. An oxygen spillover from the man- ganese to the copper species was observed by H2 temperature-programmed desorption, indicating that ammonia etching enhanced the mobility of lattice oxygen species in these oxides. The Oz tem- perature-programmed desorption measurements further revealed that ammonia etching improved the ability of these oxides to release lattice oxygen. The improvement in redox properties of the copper manganese oxides following ammonia etching was associated with enhanced catalytic performance for CO oxidation.

Tribological Properties of Few-layer Graphene Oxide Sheets as Oil-Based Lubricant Additives

The performance of a lubricant largely depends on the additives it involves. However, currently used additives cause severe pollution if they are burned and exhausted. Therefore, it is necessary to develop a new generation of green additives. Graphene oxide（GO） consists of only C, H and O and thus is considered to be environmentally friendly. So the tribological properties of the few-layer GO sheet as an additive in hydrocarbon base oil are investigated systematically. It is found that, with the addition of GO sheets, both the coefficient of friction（COF） and wear are decreased and the working temperature range of the lubricant is expanded in the positive direction. Moreover, GO sheets has better performance under higher sliding speed and the optimized concentration of GO sheets is determined to be 0.5wt%. After rubbing, GO is detected on the wear scars through Raman spectroscopy. And it is believed that, during the rubbing, GO sheets adhere to the sliding surfaces, behaving like protective films and preventing the sliding surfaces from contacting with each other directly. This paper proves that the GO sheet is an effective lubricant additive, illuminates the lubrication mechanism, and provides some critical parameters for the practical application of GO sheets in lubrication.

Structural and optical properties of thermally reduced graphene oxide for energy devices

Natural intercalation of the graphite oxide, obtained as a product of Hummer＇s method, via ultra-sonication of water dispersed graphite oxide has been carried out to obtain graphene oxide（GO） and thermally reduced graphene oxide（RGO）.Here we report the effect of metallic nitrate on the oxidation properties of graphite and then formation of metallic oxide（MO） composites with GO and RGO for the first time. We observed a change in the efficiency of the oxidation process as we replaced the conventionally used sodium nitrate with that of nickel nitrate Ni（NO_3）_2, cadmium nitrate Cd（NO_3）_2,and zinc nitrate Zn（NO_3）_2. The structural properties were investigated by x-ray diffraction and observed the successful formation of composite of MO–GO and MO–RGO（M = Zn, Cd, Ni）. We sought to study the effect on the oxidation process through optical characterization via UV-Vis spectroscopy and Fourier Transform Infrared（FTIR） spectroscopy.Moreover, Thermo Gravimetric Analysis（TGA） was carried out to confirm 〉 90% weight loss in each process thus proving the reliability of the oxidation cycles. We have found that the nature of the oxidation process of graphite powder and its optical and electrochemical characteristics can be tuned by replacing the sodium nitrate（NaNO_3） by other metallic nitrates as Cd（NO_3）_2, Ni（NO_3）_2, and Zn（NO_3）_2. On the basis of obtained results, the synthesized GO and RGO may be expected as a promising material in antibacterial activity and in electrodes fabrication for energy devices such as solar cell, fuel cell,and super capacitors.

Preparation and performance of oxidative poly-silicon-ferric coagulant PSFN

A new polymer, poly-silicon-ferric with oxidization （PSFN） coagulant was produced by adding KMnO4 and stabilizer M to poly-silicon-ferric （PSF） coagulant. The micro properties of PSFN was investigated with optical microscope, transmission electron microscope（TEM）, ultraviolet/visible absorption（UVA） scanning, infrared（IR） spectrometer and oxidation-reduction potential （ORP） meter respectively, compared to that of PSE The coagulation behavior by PSFN was investigated compared to that by PSF. The results show that the micro properties of PSF have been changed greatly due to the addition of KMnO4, and there exists KMnO4 unattached in PSFN. A kind of tetrahedron structure somewhat like the connection of Si-O-Si bonds may be formed by the complexation of Mn （maybe in various valence） with PSE PSFN has lower turbidity removal than PSF at lower dose and achieves the same when the dose reaches a definite amount, while the removal of UV254 by PSFN is higher than that by PSF almost over entire dose range with the largest difference of about 17%. PSFN has more oxidization function at acidic condition than that at basic condition, and gives stronger ability of application for treating various waters than that by PSE.

Effects of MgO and TiO_2 on the viscous behaviors and phase compositions of titanium-bearing slag

The effects of MgO and TiO_2 on the viscosity, activation energy for viscous flow, and break-point temperature of titanium-bearing slag were studied. The correlation between viscosity and slag structure was analyzed by Fourier transform infrared（FTIR） spectroscopy. Subsequently, main phases in the slag and their content changes were investigated by X-ray diffraction and Factsage 6.4 software package. The results show that the viscosity decreases when the MgO content increases from 10.00wt% to 14.00wt%. Moreover, the break-point temperature increases, and the activation energy for viscous flow initially increases and subsequently decreases. In addition, with increasing TiO_2 content from 5.00wt% to 9.00wt%, the viscosity decreases, and the break-point temperature and activation energy for viscous flow initially decrease and subsequently increase. FTIR analyses reveal that the polymerization degree of complex viscous units in titanium-bearing slag decreases with increasing MgO and TiO_2 contents. The mechanism of viscosity variation was elucidated. The basic phase in experimental slags is melilite. Besides, as the MgO content increases, the amount of magnesia–alumina spinel in the slag increases. Similarly, the sum of pyroxene and perovskite phases in the slag increases with increasing TiO_2 content.

Effects of SiC amount on phase compositions and properties of Ti_3SiC_2-based composites

The phase compositions and properties of Ti3SiC2-based composites with SiC addition of 5%-30% in mass fraction fabricated by in-situ reaction and hot pressing sintering were studied. SiC addition effectively prevented TiC synthesis but facilitated SiC synthesis. The Ti3SiC2/Ti C-SiC composite had better oxidation resistance when SiC added quantity reached 20% but poorer oxidation resistance with SiC addition under 15% than Ti3SiC2/TiC composite at higher temperatures. There were more than half of the original SiC and a few Ti3SiC2 remaining in Ti3SiC2/Ti C-SiC with 20% SiC addition, but all constituents in Ti3Si2/TiC composite were oxidized after 12 h in air at 1500 °C. The oxidation scale thickness of TS30, 1505.78 μm, was near a half of that of T,2715 μm, at 1500 °C for 20 h. Ti3SiC2/Ti C composite had a flexural strength of 474 MPa, which was surpassed by Ti3SiC2/TiC-SiC composites when SiC added amount reached 15%. The strength reached the peak of 518 MPa at 20% SiC added amount.

Effects of structures of molybdenum catalysts on selectivity in gas-phase propylene oxidation

Molybdenum-based catalysts for the gas-phase oxidation of propylene with air were investigated. Various types of silica-supported molybdenum oxide and molybdenum-bismuth mixed oxide cata- lysts were prepared from inorganic and organometallic molybdenum precursors using wet impregnation and physical vapor deposition methods. The epoxidation activities of the prepared cata- lysts showed direct correlations with their nanostructures, which were identified using transmission electron microscopy. The appearance of a partly or fully crystalline molybdenum oxide phase, which interacted poorly with the silica support, decreased the selectivity for propylene oxide for- mation to below 10%; non-crystalline octahedrally coordinated molybdenum species anchored on the support gave propylene oxide formations greater than 55%, with 11% propylene conversion. Electrochemical characterization of molybdenum oxides with various morphologies showed the importance of structural defects. Direct promotion by bismuth of the epoxidation reactivities over molybdenum oxides is disputed.

Influence of Deposition Pressure on Properties of ZnO：Al Films Fabricated by RF Magnetron Sputtering

Transparent conductive aluminum doped zinc oxide（ZnO：Al,AZO） films were prepared on glass substrates by rf（radio frequency） magnetron sputtering from ZnO： 3wt% Al_2O_3 ceramic target. The effect of argon gas pressure（PAr） was investigated with small variations to understand the influence on the electrical, optical and structural properties of the films. Structural examinations using X-ray diffraction（XRD） and scanning electron microscopy（SEM） showed that the ZnO：Al thin films were（002） oriented. The resistivity values were measured by four-point probe with the lowest resistivity of 5.76×10^（-4） Ω？cm（sheet resistance=9.6 Ω/sq. for a thickness=600 nm） obtained at the PAr of 0.3 Pa. The transmittance was achieved from ultravioletvisible（UV-VIS） spectrophotometer, 84% higher than that in the visible region for all AZO thin films. The properties of deposited thin films showed a significant dependence on the PAr.

Preparation of new sunscreen materials Ce_(1-x)Zn_xO_(2-x) via solid-state reaction at room temperature and study on their properties

Superfine cerium-zinc oxides Ce1-xZnxO2-x with x = 0, 0.1, 0.3, 0.5, and 1.0 were obtained by grinding Ce（SO4）2·4H2O, ZnSO4·7H2O and NH4HCO3 under the condition of surfactant PEG-400 being present at room temperature, washing the mixture with water to remove soluble inorganic salts, drying at 80°C, and calcining.The precursor and its calcined samples were characterized using thermogravimetry and differential thermal analyses（TG/DTA）, UV-vis absorption spectroscopy, X-ray powder diffraction（XRD）, and scanning electron microscopy（SEM）.The results showed that superfine Ce1-xZnxO2-x behaved as an excellent UV-shielding material.The ZnO-doped CeO2 can facilitate the formation of crystalline state CeO2.The catalytic ability of products used in air oxidation of castor oil was investigated.The results showed that the catalytic abilities of products decreased with increasing zinc amount.

Ordered Mesoporous Carbon/SnO_2 Composites as the Electrode Material for Supercapacitors

A series of composites as electrode materials for supercapacitors were prepared via incipient wetness impregnation method utilizing ordered mesoporous carbon （OMC） and tin （IV） oxide （SnO2） with different ratio.The structure and electrochemical properties of the OMC/SnO2 composites were characterized by XRD,TEM and cyclic voltammetry （CV）.Pore characteristics were measured by nitrogen adsorption and desorption isotherms.The results show that the structure and electrochemical properties of the composites depend mainly on the loading amount of SnO2 in the ordered mesoporous carbon.The optimum amount of SnCl4 added is found to be 40 % （1.54 g ethanol-based SnCl4·5H2O added to 1 g OMC） of the saturated solution.The specific capacitance of the composite of optimum amount of SnCl4 （200 F g-1） is nearly three times of that of the pristine SnO2 （72 F g-1） at the scan rate of 5 mV s-1,and its specific capacitance is almost equal to that of the ordered mesoporous carbon （126 F g-1） at the scan rate of 200 mV s-1.Meanwhile,it has better specific volumetric energy density than OMC due to its higher density.Besides,in the potential range of 0-0.9 V the composite electrode material exhibits a stable cycle life after 500 cycles.

Characterization of structural and electrical properties of ZnO tetrapods

ZnO tetrapods were synthesized by a typical thermal vapor-solid deposition method in a horizontal tube furnace.Structural characterization was carried out by transmission electron microscopy （TEM） and select-area electron diffraction （SAED）,which shows the presence of zinc blende nucleus in the center of tetrapods while the four branches taking hexagonal wurtzite structure.The electrical transport property of ZnO tetrapods was investigated through an in-situ nanoprobe system.The three branches of a tetrapod serve as source,drain,and ＂gate＂,respectively;while the fourth branch pointing upward works as the force trigger by vertically applying external force downward.The conductivity of each branch of ZnO-tetrapods increases 3-4 times under pressure.In such situation,the electrical current through the branches of ZnO tetrapods can be tuned by external force,and therefore a simple force sensor based on ZnO tetrapods has been demonstrated for the first time.

Enhanced oxidation and overheating resistance of the extruded Mg–Zn–Al–Mn magnesium alloy by Calcium addition

The effects of Ca addition on the microstructure and oxidation properties of a new Mg alloy were studied.The oxidation behavior of the alloys was analyzed by thermal analysis and material characterization of the alloys exposed in flame environment;and both electrical and induction furnaces.Moreover,the surface layers were characterized using field emission scanning electron microscopy,and X-ray diffraction technique.It was found that increasing the Ca addition reduces the grain size and increases the fraction of the secondary phases,and enhances the mechanical properties.Moreover,increasing the Ca contents resulted in the formation of a dense CaO/MgO layer on the surface prohibited the oxygen diffusion and assisted in protection of the substrate against further oxidation.Therefore,ignition temperature was increased from 680℃ to 890℃ after addition of the Ca element.The mechanical properties and ignition behavior of the current materials was compared with the literature which it showed an excellent combination of the properties in the developed alloys.

Oxidation Properties of Silver Alloy Powders and Microstructures of Oxidized Powders for Making Electrical Contact Composites

The oxidation properties of silver alloy powders and microstructures of oxidized powders have been investigated by thermo gravity analysis(TGA), scanning electron microscopy(SEM) and wave dispersive X ray spectroscopy(WDEX). Ag Sn RE alloy powders have been oxidized completely at 610 ℃ within 60 min, with an external pure silver scale forming around each oxidized particle. It is useful to produce electrical contact composites. The excellent oxidation properties of Ag Sn RE alloy powders are attributed to the ideal microstructure of the oxidized powders.

Apparent activation energy of mineral in open pit mine based upon the evolution of active functional groups

This study aimed to investigate the mechanism of mineral spontaneous combustion in an open pit. On the study of coal and mineral mixture in open pit mines, as well as through the specifc surface area and Search Engine Marketing (SEM) experiments, the specifc surface area and aperture characteristics of distribution of open pit coal sample and pit mineral mixture samples were analyzed. Thermal analysis experiments were used to divide the oxidation process was divided into three stages, and the thermal behavior characteristics of experimental samples were characterized. On the basis of the stage division, we explored the transfer law of the key active functional groups of the experimental samples. The apparent activation energy calculation of the key active groups, performed by combining the Achar diferential method with the Coats–Redfern integral method, microstructural and oxidation kinetic properties were revealed. The resulted showed that the mixed sample had high ash, the fxed carbon content was reduced, the specifc surface area was far lower than the raw coal, the large aperture distribution was slightly higher than the medium hole, the micropore was exceptionally low, the gas adsorption capacity was weaker than the raw coal, the pit coal sample had the exceedingly more active functional groups, easy to react with oxygen, more likely to occur naturally, and its harm was relatively large. The mixed sample contained the highest C–O–C functional group absorbance. The functional groups were mainly infuenced by the self-OH content, alkyl side chain, and fatty hydrocarbon in the sample. The main functional groups of the four-like mixture had the highest apparent activation energy, and the two reactions were higher in the low-temperature oxidation phase.

Effects of Scale Composition on Oxidation Kinetics of Fe-based Superalloy

By oxidation weight gain method, four groups of Fe-based superalloys with different content of chromium, aluminium and silicon were tested at 1 200 ℃ for 500 hours. According to the oxidation weight gains, the oxidation kinetic curves were plotted, and the equations were regressed by least square method and non-linear curve fitting. The effects of different scale compositions on the morphology and oxidation kinetic law were studied further by analysis of X-ray diffraction （XRD） and scanning electron microscope （SEM）. It is found that the compounded scale is composed of Cr2O3, Al2O3, SiO2 and FeCr2O4, with compact structure and fine grains, possessing complete oxidation resistance at 1 200 ℃, and the oxidation kinetic curve follows the power function of y=axb （a0, 0b1）. When the compounded scale lacks Al2O3 or SiO2, it becomes weak in oxidation resistance, but the oxidation kinetic curve still follows the power function with bigger parameter b. When Cr2O3 is absent, the kinetic curve shows two parts： the slow adding of oxidation weight gains at the beginning and the ascending line in the end. Such scale loses oxidation resistance completely.

Structural,Morphological and Electrical Properties of In-Doped Zinc Oxide Nanostructure Thin Films Grown on p-Type Gallium Nitride by Simultaneous Radio-Frequency Direct-Current Magnetron Co-Sputtering

Zinc oxide （ZnO） is one of the most promising and frequently used semiconductor materials. In-doped nanos- tructure ZnO thin films are grown on p-type gallium nitride substrates by employing the simultaneous rf and dc magnetron co-sputtering technique. The effect of In-doping on structural, morphological and electrical properties is studied. The different dopant concentrations are accomplished by varying the direct current power of the In target while keeping the fixed radio frequency power of the ZnO target through the co-sputtering deposition technique by using argon as the sputtering gas at ambient temperature. The structural analysis confirms that all the grown thin films preferentially orientate along the c-axis with the wurtzite hexagonal crystal structure without having any kind of In oxide phases. The presenting Zn, 0 and In elements＇ chemical compositions are identified with EDX mapping analysis of the deposited thin films and the calculated M ratio has been found to decrease with the increasing In power. The surface topographies of the grown thin films are examined with the atomic force microscope technique. The obtained results reveal that the grown film roughness increases with the In power. The Hall measurements ascertain that all the grown films have n-type conductivity and also the other electrical parameters such as resistivity,mobility and carrier concentration are analyzed.