About 300 μm thickness uniform thermal barrier coatings （TBCs） were deposited on the 1Cr18Ni9Ti samples by solution precursor plasma spray （SPPS）.The analysis methods,such as TEM,SEM,and XRD were used to characte...
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About 300 μm thickness uniform thermal barrier coatings （TBCs） were deposited on the 1Cr18Ni9Ti samples by solution precursor plasma spray （SPPS）.The analysis methods,such as TEM,SEM,and XRD were used to characterize the coatings in the aspects of microstructure and phase *** samples were quenched from 1121 ℃ to room temperature by forced-air to measure the thermal cycling *** density were measured by means of water *** experimental results show that grain size of the SPPS TBCs is about 30 nm with desired tetragonal phase ZrO2,and the SPPS TBCs（with 16% porosity） consist of arcuate pores,gelatin and melted *** hardness of the coatings is HR45Y38.5 and bond strength between coatings and substrates is 24.2 *** thermal shock test show the coatings have a average life of 500 cycles which is about 2.5 times than that of conventional air plasma spray （APS） TBCs.
Polycrystalline samples of Sr5PrTi3Ta7O30 （SPTT） and Sr5EuTi3Ta7O30 （SETT） compounds were prepared by high-temperature solid-state reaction method and their formation, structure and dielectric properties were stud...
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Polycrystalline samples of Sr5PrTi3Ta7O30 （SPTT） and Sr5EuTi3Ta7O30 （SETT） compounds were prepared by high-temperature solid-state reaction method and their formation, structure and dielectric properties were studied. They are found to be ferroelectric phase of filled tetragonal tungsten bronze （TB） structure at room temperature and undergoes diffuse type of ferroelectric-paraelectric phase transition around 34 ℃ and 31 ℃, respectively. At 1 MHz SPTT exhibits high dielectric constants of 177 and low dielectric losses of 3.5×10^-4 and SETT has high dielectric constants of 125 and low dielectric losses of 2.4×10^-3.
Graphene was prepared and used as an adsorbent for removal of cationic red X-GRL from aqueous solutions. The physico-chemical properties of graphene were characterized by the transmission electron microscope (TEM), th...
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Graphene was prepared and used as an adsorbent for removal of cationic red X-GRL from aqueous solutions. The physico-chemical properties of graphene were characterized by the transmission electron microscope (TEM), the Brunauer-Emmett-Teller (BET) specific surface area measurement, atomic force microscope (AFM), and Raman microscope. The adsorption properties of cationic red X-GRL onto graphene were studied as a function of pH, adsorbent dosage, contact time, and temperature. Kinetic data were well fitted by a pseudo second-order model. Langmuir and Freundlich adsorption models were applied to describe the isotherms and isotherm constants. Equilibrium data agreed very well with the Langmuir model. Thermodynamic studies showed that the adsorption was a spontaneous and endothermic process.
A facile and large-scale synthesis method to fabricate silver hollow microspheres with controllable morphologies and shell thickness is described using low-cost glass microspheres as templates. The method mainly invol...
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A facile and large-scale synthesis method to fabricate silver hollow microspheres with controllable morphologies and shell thickness is described using low-cost glass microspheres as templates. The method mainly involves two steps of the preparation of silver-coated glass microsphere core–shell particles by a controllable liquid reduced reaction of Ag[（NH3）2]＋ solution, which only produces silver nanoparticles anchored on the surface of the thiolated glass microsphere templates, and the removal of glass microspheres by wet chemical etching with HF solution. The products are well characterized by field emitted scanning electron microscopy （SEM）, transmitted electron microscopy （TEM）, X-ray photoelectron spectra （XPS）, X-ray diffraction （XRD） and energy dispersive X-ray （EDX） etc. The as-prepared core-shell particles and hollow particles have even and compact silver shells. The electromagnetic shielding coatings based on the silver hollow microspheres are demonstrated to have high conductivity, excellent shielding effectiveness and long durability, suggesting that the silver hollow microspheres obtained here are a novel light-weight electromagnetic shielding filler and will have extensive applications in the electromagnetic compatibility fields.
A 3-D finite element model of two-stage thermoelectric generator based on low-temperature thermoelectric material bismuth-telluride and medium-temperature thermoelectric material skutterudites is established. Based on...
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ISBN:
(纸本)9781424480364
A 3-D finite element model of two-stage thermoelectric generator based on low-temperature thermoelectric material bismuth-telluride and medium-temperature thermoelectric material skutterudites is established. Based on the formal model, structural optimization of the two-stage thermoelectric generator is carried out. Results show that, reasonable design of the structure of two-stage thermoelectric generator can take full advantage of the characteristics of thermoelectric materials and effectively improve the performance of power generation. If contact resistance and all heat losses are neglected, the conversion efficiency of the two-stage thermoelectric generator can reach a value of 17.02%.
Highly sensitive and selective nanosensor for labile iron pool (LIP) determination, has been designed and prepared by immobilization of Fluoresceine–Desferrioxamine (Fl–DFO), a bifunctional fluoro-siderophore probe ...
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Highly sensitive and selective nanosensor for labile iron pool (LIP) determination, has been designed and prepared by immobilization of Fluoresceine–Desferrioxamine (Fl–DFO), a bifunctional fluoro-siderophore probe molecule with great affinity for iron ions (pK f = 30.7), into highly ordered mesoporous silica structure. Different immobilization methods of Fl–DFO molecules, such as their encapsulation in surfactant micelles used as templating agents for the synthesis of mesoporous silica, direct impregnation into the mesochannels of as-synthesized mesoporous silica and their surface anchoring by covalent binding with propylamine groups implanted by post-synthesis on the internal surface of mesochannels, have been explored. Each nanohybrid has been fully characterized by small angle XRD, TEM, SEM, solid state 29 Si and 13 C MAS NMR and N 2 adsorption–desorption. The fluorescence properties of nanohybrids obtained have been correlated with the immobilization methods, generating interesting information concerning the localization of Fl–DFO molecules in the channels of mesoporous silica. The leaching of Fl–DFO molecules from mesoporous materials has been investigated. The nanosensor prepared by surface anchoring of Fl–DFO at the internal surface of mesochannels showed high performances with no leaching effect and high sensitivity in regards to its responses to ferric ions. Its fluorescence intensity decreased as soon as first Fe III ions are in contact with this nanosensor. A linear relationship between the fluorescence intensity and the ferric ions concentration was observed in low micromolar range. The selectivity of this nanosensor towards other metal ions has also been tested and shown its high affinity to ferric ions. This study can allow the design of a stable, portable, simple, regenerable and cost-effective nanosensor highly sensitive and selective for iron ions with detection limits in the range of cellular LIP in cells, e.g. lower micromolar range.
The performance of composite ceramic armor penetrated by rod projectile was studied by both numerical simulation and *** penetration and damage mechanisms of the projectile-armor after high-speed collision were also o...
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The performance of composite ceramic armor penetrated by rod projectile was studied by both numerical simulation and *** penetration and damage mechanisms of the projectile-armor after high-speed collision were also observed by high-speed *** experimental results showed that the ballistic performance of composite ceramic armor was highly affected by the density,hardness and toughness of bulletproof *** flow stress of the failed bulletproof ceramic is not only related to the pressure but also related to the strain *** phenomenological method based on Bodner-Partom ceramic model was introduced to derive the growth rate of *** simulation results show good agreement with the experimental results.
The effects of activated sintering technology of H2 atmosphere sintering on the microstructure and properties of W-15Cu alloy using ultrafine W-15Cu composite powder fabricated by spray drying calcining-continuous red...
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The effects of activated sintering technology of H2 atmosphere sintering on the microstructure and properties of W-15Cu alloy using ultrafine W-15Cu composite powder fabricated by spray drying calcining-continuous reduction technology were *** experimental results showed that W-15Cu alloy,consolidated by activated sintering technology of H2 atmosphere sintering for 1 h at 1300 ℃,with 98.5 % relative density,transverse rupture strength 1218 MPa,Vickers hardness HV0.5 378,average grain size about 1.2 μm and thermal conductivity 192 W/m·K,was *** comparison to the normal sintering process,activated sintering process to W-15Cu alloy could be achieved at lower sintering ***,better properties in activated sintered compacts were obtained,and activated sintering process resulted in finer microstructure and excellent properties.
Two kinds of azo polysemicarbazides were prepared based on 3,3＇-azobis（benzoylhydrazide）（ABH） and two kinds of diisocyanates via solution *** structures were characterized by Fourier-transform infrared（FT-IR） t...
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Two kinds of azo polysemicarbazides were prepared based on 3,3＇-azobis（benzoylhydrazide）（ABH） and two kinds of diisocyanates via solution *** structures were characterized by Fourier-transform infrared（FT-IR） technique and elemental *** viscosities of the polymers were 0.32 and 0.29 dL/g and both could be dissolved in H2SO4 and polar organic *** gravimetric analysis（TGA） presented a multi-step degradation and a decomposition temperature range of 230-280 ℃.And photoisomerization of the azo polymers in solvent of N,N-dimethyl acetamide（DMAc） was confirmed by Ultraviolet-visible spectroscopy（UV-Vis）,suggested the isomerization appearing under the ultraviolet irradiation at 365 nm and recovering completely by visible light irradiation or kept in the *** electron microscopy（TEM） of polysemicarbazides before and after soaking in bovine serum albumin（BSA） solution confirmed the biocompatibility of azo polymers.
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