Preparation of CuS Hollow Microsphere by a Simple Hydrothermal Method and its Catalytic Property

2012 ◽  
Vol 535-537 ◽  
pp. 329-332 ◽  
Author(s):  
Ming Rui Wang ◽  
Wen Jiang Li ◽  
Mei Ling Pan
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Hollow Microsphere ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
Catalytic Material ◽  
Phase Pure ◽  
Scanning Electron

A simple method was applied to fabricate phase-pure hollow CuS microspheres. The obtained product was characterized by X-ray diffraction, scanning electron microscopy, photoluminescence spectra and UV-Vis absorption spectroscopy. Further, the catalytic activity of CuS spheres was evaluated by the decolorization of Rhodamine B in the presence of hydrogen peroxide solution at room temperature. The results indicated that the product showed a good optical propertie, and the hollow sphere CuS could be an effective catalytic material.

ROOM TEMPERATURE PHOTOLUMINESCENCE OF POLYCRYSTALLINE SIC PREPARED FROM CARBON-SATURATED SI MELT

2002 ◽  
Vol 16 (06n07) ◽  
pp. 1047-1051
Author(s):  
JIANPING MA ◽  
ZHIMING CHEN ◽  
GANG LU ◽  
MINGBIN YU ◽  
LIANMAO HANG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Uv Light ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Composition And Structure ◽  
Light Excitation ◽  
Scanning Electron

Intense photoluminescence (PL) has been observed at room temperature from the polycrystalline SiC samples prepared from carbon-saturated Si melt at a temperature ranging from 1500 to 1650°C. Composition and structure of the samples have been confirmed by means of X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. PL measurements with 325 nm UV light excitation revealed that the room temperature PL spectrum of the samples consists of 3 luminescent bands, the peak energies of which are 2.38 eV, 2.77 eV and 3.06 eV, respectively. The 2.38 eV band is much stronger than the others. It is suggested that some extrinsic PL mechanisms associated with defect or interface states would be responsible to the intensive PL observed at room temperature.

Influence of Silicon Nitride on Properties of Corundum Based Castable

2013 ◽  
Vol 634-638 ◽  
pp. 2358-2361
Author(s):  
Jun Cong Wei ◽  
Li Rong Yang
Keyword(s):  
Electron Microscopy ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Cold Strength ◽  
X Ray ◽  
Refractory Castables ◽  
Shock Resistance ◽  
Scanning Electron

The effects of Si3N4 addition on the room temperature physical properties and thermal shock resistance properties of corundum based refractory castables were investigated using brown corundum, white corundum and alumina micropowder as the starting materials and pure calcium aluminate as a binder. The phase composition, microstructure, mechanical properties of corundum based castables were investigated by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that as the increase in Si3N4 addition, the bulk density decreased and apparent porosity increased, the cold strength deduced. However, the residual strength rate increased. That is, the thermal shock resistance was improved. This is because even though the introduction of Si3N4 inhibited the sintering of material and deduced the compactness, microcracks were produced in the materials due to a difference in thermal expansion coefficient. So the thermal shock resistance of corundum based castable was improved.

N-type Ba0.2Co4Sb11.5Te0.5: Optimization of thermoelectric properties by different pressures

2019 ◽  
Vol 33 (03) ◽  
pp. 1950027 ◽  
Author(s):  
Jiaxiang Chen ◽  
Xiaopeng Jia ◽  
Yuewen Zhang ◽  
Haiqiang Liu ◽  
Baomin Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Seebeck Coefficient ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Absolute Value ◽  
X Ray ◽  
Coefficient Increase ◽  
Maximum Power Factor ◽  
Scanning Electron

The polycrystalline skutterudite [Formula: see text] were successfully synthesized from 1.5 GPa to 3.5 GPa by the high pressure and high temperature (HPHT) method. Negative Seebeck coefficient confirmed the n-type conductivity of all samples. The phase compositions of samples were investigated by X-ray diffraction (XRD) and the microstructures were observed by scanning electron microscopy (SEM). It was found that the grains appeared smaller and the grain boundaries became more abundant when pressures were higher. We measured the electrical properties from room temperature to 723 K. Both the electrical resistivity and absolute value of Seebeck coefficient increase with the increasing synthetic pressure. At 723 K, the maximum power factor of [Formula: see text] was obtained for the sample synthesized under 3 GPa. The maximum ZT value of 0.61 was reached by [Formula: see text] synthesized under 3 GPa and measured at 723 K.

scholarly journals Layer-by-Layer Self-Assembled Ferrite Multilayer Nanofilms for Microwave Absorption

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Jiwoong Heo ◽  
Daheui Choi ◽  
Jinkee Hong
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Precursor Solution ◽  
Ferrite Nanoparticles ◽  
Energy Dispersive ◽  
Layer By Layer ◽  
X Ray Diffraction ◽  
Simple Method ◽  
X Ray ◽  
Scanning Electron

We demonstrate a simple method for fabricating multilayer thin films containing ferrite (Co0.5Zn0.5Fe2O4) nanoparticles, using layer-by-layer (LbL) self-assembly. These films have microwave absorbing properties for possible radar absorbing and stealth applications. To demonstrate incorporation of inorganic ferrite nanoparticles into an electrostatic-interaction-based LbL self-assembly, we fabricated two types of films: (1) a blended three-component LbL film consisting of a sequential poly(acrylic acid)/oleic acid-ferrite blend layer and a poly(allylamine hydrochloride) layer and (2) a tetralayer LbL film consisting of sequential poly(diallyldimethylammonium chloride), poly(sodium-4-sulfonate), bPEI-ferrite, and poly(sodium-4-sulfonate) layers. We compared surface morphologies, thicknesses, and packing density of the two types of ferrite multilayer film. Ferrite nanoparticles (Co0.5Zn0.5Fe2O4) were prepared via a coprecipitation method from an aqueous precursor solution. The structure and composition of the ferrite nanoparticles were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy, and scanning electron microscopy. X-ray diffraction patterns of ferrite nanoparticles indicated a cubic spinel structure, and energy dispersive X-ray spectroscopy revealed their composition. Thickness growth and surface morphology were measured using a profilometer, atomic force microscope, and scanning electron microscope.

scholarly journals Properties of Nanostructure Bismuth Telluride Thin Films Using Thermal Evaporation

2017 ◽  
Vol 2017 ◽  
pp. 1-4 ◽  
Author(s):  
Swati Arora ◽  
Vivek Jaimini ◽  
Subodh Srivastava ◽  
Y. K. Vijay
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Bismuth Telluride ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Thermal Evaporation Method ◽  
X Ray ◽  
Scanning Electron

Bismuth telluride has high thermoelectric performance at room temperature; in present work, various nanostructure thin films of bismuth telluride were fabricated on silicon substrates at room temperature using thermal evaporation method. Tellurium (Te) and bismuth (Bi) were deposited on silicon substrate in different ratio of thickness. These films were annealed at 50°C and 100°C. After heat treatment, the thin films attained the semiconductor nature. Samples were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to show granular growth.

A Simple Method for Controlling the Morphology of CuO Nanostructures by Droplet

2012 ◽  
Vol 535-537 ◽  
pp. 280-283 ◽  
Author(s):  
Hao Ran An ◽  
Feng Shi Cai ◽  
Xue Wei Wang ◽  
Zhi Hao Yuan
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscope ◽  
Growth Mechanisms ◽  
X Ray Diffraction ◽  
Simple Method ◽  
Hydrophobic Substrate ◽  
X Ray ◽  
Shape Selective ◽  
Scanning Electron

Different morphology CuO nanostructures, including platelets, flower-like were simply synthesized at 350 °C controlled by droplet on hydrophobic substrate. This is a simple method which does not require any template, catalyst, or surfactant but can control the morphology of CuO from platelets to flowerlike. The morphologies are strongly dependent on the volume of droplet. Scanning electron microscopy (SEM), Optical microscope and X-ray diffraction (XRD) were used to observe the morphology, crystallinity, and chemical composition of the CuO structures. Growth mechanisms for shape selective CuO synthesis were proposed based on these results.

Effect of Au on the Performance of Porous Silicon/V2O5 Nanorods Heterojunctions to NO2 Gas

NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650079 ◽  
Author(s):  
Wenjun Yan ◽  
Ming Hu ◽  
Jiran Liang ◽  
Dengfeng Wang ◽  
Yulong Wei ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Porous Silicon ◽  
Room Temperature ◽  
Au Nanoparticles ◽  
Analytical Techniques ◽  
Heating Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

A novel composite of Au-functionalized porous silicon (PS)/V2O5 nanorods (PS/V2O5:Au) was prepared to detect NO2 gas. PS/V2O5 nanorods were synthesized by a heating process of pure vanadium film on PS, and then the obtained PS/V2O5 nanorods were functionalized with dispersed Au nanoparticles. Various analytical techniques, such as field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), have been employed to investigate the properties of PS/V2O5:Au. Herein, the PS/V2O5:Au sample exhibited improved NO2-sensing performances in response, stability and selectivity at room temperature (25[Formula: see text]C), compared with the pure PS/V2O5 nanorods. These phenomena were closely related to not only the dispersed Au nanoparticles acting as a catalyst but also the p-n heterojunctions between PS and V2O5 nanorods. Whereas, more Au nanoparticles suppressed the improvement of response to NO2 gas.

PREPARATION OF LUMINESCENT PbWO4 MICROCRYSTALS WITH HIERARCHICAL STRUCTURES BY USING MICROWAVE IRRADIATION HEATING METHOD

2010 ◽  
Vol 24 (32) ◽  
pp. 3081-3087 ◽  
Author(s):  
GENGPING WAN ◽  
GUIZHEN WANG
Keyword(s):  
Electron Microscopy ◽  
Microwave Irradiation ◽  
Room Temperature ◽  
Hierarchical Structures ◽  
X Ray Diffraction ◽  
Lead Tungstate ◽  
Heating Method ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Scanning Electron

Lead tungstate ( PbWO 4) microcrystals with hierarchical structures have been successfully synthesized via a facile microwave irradiation heating method. The cetyltrimethylammonium bromine (CTAB) and microwave-heated power were found to play an important role in the morphological control of resulting PbWO 4 mirocrystals. The products were characterized by the techniques of powder X-ray diffraction and field-emission scanning electron microscopy. A growth mechanism of PbWO 4 microstructures was proposed. The luminescence properties of the final products were investigated and the as-prepared PbWO 4 microcrystals displayed a very unique room-temperature photoluminescence compared to the reported results.

scholarly journals Metal Injection Moulding of Superelastic TiNi Parts

2016 ◽  
Vol 704 ◽  
pp. 173-182 ◽  
Author(s):  
J. Eric Bidaux ◽  
Alexandra Amherd Hidalgo ◽  
Hervé Girard ◽  
Mikel Rodriguez-Arbaizar ◽  
Lionel Reynard ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Injection Moulding ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metal Injection Moulding ◽  
Shape Memory Properties ◽  
Production Techniques ◽  
Near Net Shape ◽  
Scanning Electron

TiNi shape-memory properties are successfully used today for the fabrication of various technical devices. The limited machinability and high cost of TiNi encourage the use of near-net shape production techniques such as metal injection moulding. In this work TiNi alloys tensile test specimens are produced by metal injection moulding from pre-alloyed powders. A binder based on a mixture of polyethylene, paraffin wax and stearic acid is used. Parts with a density of about 96.6% of theoretical density are obtained. Scanning electron microscopy coupled with EDX measurements reveals a microstructure consisting of a TiNi matrix with small Ti4Ni2Ox and TiC inclusions. DSC and X-ray diffraction observations indicate the presence of additional Ni4Ti3 precipitates. The parts exhibit full superelasticity at room temperature even for strains of up to 4%, without the need for additional thermal post-treatments. Ultimate tensile strengths up to 980 MPa are obtained.

Effects of V2O5 on the synthesis of Ba2Ti9O20 powders

2005 ◽  
Vol 20 (10) ◽  
pp. 2741-2744 ◽  
Author(s):  
Huixing Lin ◽  
Wei Chen ◽  
Lan Luo
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Scanning Electron Microscopy ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Eutectic Liquid ◽  
X Ray ◽  
Intermediate Phases ◽  
Phase Pure ◽  
Scanning Electron

Phase-pure Ba2Ti9O20 powders were made by doping 3 wt% of V2O5 to a Ba:Ti = 2:9 molar composition, and the effects of the dopant on the phase formation were investigated. The study shows that BaTiO3, BaTi2O5, and BaTi4O9 were the intermediate phases before the formation of Ba2Ti9O20 for samples with or without V2O5. However, with V2O5 doping, the temperature at which Ba2Ti9O20 occurred were lowered from 1150 to 1050 °C and single phase Ba2Ti9O20 powders was easily obtained at 1150 °C for 2 h. Microstructure of the powders was examined by field emission scanning electron microscopy. No evidence of V2O5–Ba2Ti9O20 solid-solution was found by x-ray diffraction and energy-dispersive spectroscopy. The benefit of V2O5 to facilitate the Ba2Ti9O20 synthesis is most probably due to a vanadium-containing eutectic liquid phase which accelerates the migration of reactant species.

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