Single crystalline hexagonal CdS nanowires were prepared by a solvothermal method using ethylenediamine as a solvent. Pt/CdS nanocomposites were produced by different reduction methods and characterized by X-ray diffr...
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Mg-Al bonded composite materials expand Mg and Al alloys' applications by combining their unique performances together. However, the formation of Mg-Al intermetallic compounds in interface zone of Mg/Al directly-b...
Mg-Al bonded composite materials expand Mg and Al alloys' applications by combining their unique performances together. However, the formation of Mg-Al intermetallic compounds in interface zone of Mg/Al directly-bonded joint seriously obstructs its further development. To solve this problem, Mg-Ag-Al multilayer composite materials have been successfully prepared by diffusion bonding technology. The effect of key process parameter (bonding temperature) on microstructure of this material has been mainly investigated. The results show that Mg and Al were well bonded by using silver interlayer when the bonding temperature exceeded 370°C. But Mg17Al12 and Mg2Al3 compounds were formed in the interface zone at temperatures higher than 420°C. By means of controlling the bonding temperature (380 °C–420 °C), silver interlayer effectively restrained the generation of Mg-Al intermetallic compounds, and Mg-Ag intermetallic compounds (Mg3Ag, MgAg) were formed in the interface zone instead.
Introduction Many studies focused on using lignocellulosic biomass as an ideal feedstock for producing biofuels. By comparison, other bioresources, for example rosin fromthe pine tree, received less attention
Introduction Many studies focused on using lignocellulosic biomass as an ideal feedstock for producing biofuels. By comparison, other bioresources, for example rosin fromthe pine tree, received less attention
The downgraded and upgraded BaZrxTi2−xO5 (x=0, 0.01, 0.02, 0.03 and 0.04) films normal to Pt/Ti/SiO2/Si substrates were prepared by sol-gel method. The microstructure and dielectric properties of the compositionally g...
The downgraded and upgraded BaZrxTi2−xO5 (x=0, 0.01, 0.02, 0.03 and 0.04) films normal to Pt/Ti/SiO2/Si substrates were prepared by sol-gel method. The microstructure and dielectric properties of the compositionally graded BaZrxTi2−xO5 films were investigated. The single-phase downgraded and upgraded films were obtained as the films were annealed at 900 °C for 30 min. The downgraded BaZrxTi2−xO5 film had dense surface, while there were pores in the surface of the upgraded BaZrxTi2−xO5 film. The thicknesses of both upgraded and downgraded BaZrxTi2−xO5 films were about 500 nm. The values of permittivity (r) for the downgraded and upgraded BaZrxTi2−xO5 films were 84 and 100, respectively, at 1 MHz.
Supercritical carbon dioxide (ScCO2) foaming which is inexpensive and environmental friendly has been widely used to prepare polymer-based microporous materials. In this paper, PMMA graded microporous materials were f...
Supercritical carbon dioxide (ScCO2) foaming which is inexpensive and environmental friendly has been widely used to prepare polymer-based microporous materials. In this paper, PMMA graded microporous materials were foamed by PMMA matrix after an unstable saturation process which was done under supercritical condition of 28MPa and 50 °C. The scanning electron microscopy (SEM) was utilized to observe the morphology of the graded foam. A gas adsorption model was proposed to predict the graded gas concentration in the different region of the polymer matrix. The SEM results showed that the solid and foam region of the graded foam can be connected without laminated layers. With the increasing thickness position of the graded microporous foam, the cell size increased from 3.4 to 27.5 μm, while the cell density decreased from 1.04 × 109 to 1.96 × 107 cells/cm3. It also found that the gradient microporous structure of the foam came from graded gas concentration which was obtained in the initial saturation process.
The microstructure deformation and fracture mechanisms of particulate-filled polymer composites were studied based on microstructure observations in this paper. By using in-situ tensile test system under scanning elec...
The microstructure deformation and fracture mechanisms of particulate-filled polymer composites were studied based on microstructure observations in this paper. By using in-situ tensile test system under scanning electron microscopy, three different composites composed of polymer binder filled by three different types of particles, namely Al particles, AP particles and HMX particles, with the same total filler content were tested. The roles of initial microstructure damage and particle type on the microstructure deformation and damage are highlighted. The results show that microstructure damage starts with the growth of the initial microvoids within the binders or along the binder/particle interfaces. With the increase of strain, the microstructure damages including debonding at the particle/binder interface and tearing of the binder lead to microvoid coalescence, and finally cause an abrupt fracture of the samples. Coarse particles lead to an increase of debonding at the particle/binder interface both in the initial state and during the loading process, and angular particles promote interface debonding during the loading process.
The research on aggregation-induced emission(AIE)has drawn increasing interests in the past *** the efforts scientists paid,a variety of AIE systems have been developed,among which the tetraphenylethelene and silole d...
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The research on aggregation-induced emission(AIE)has drawn increasing interests in the past *** the efforts scientists paid,a variety of AIE systems have been developed,among which the tetraphenylethelene and silole derivatives are the most *** of new AIE systems could further enrich the AIE molecules and promote the development of AIE *** this communication,we prepared a new AIE system based on1,2,4,6-tetraphenylpyridinium ions according to the restriction of intramolecular rotation *** molecules could be facilely synthesized via one-step and one-pot *** ionic AIE-active molecules could find wide application in sensing and optoelectronic areas.
The fabrication of polymeric foams with gradient density is a key to investigate the response of materials in quasi-isentropic loading. In this work, a non-traditional approach was proposed to fabricate the polymeric ...
The fabrication of polymeric foams with gradient density is a key to investigate the response of materials in quasi-isentropic loading. In this work, a non-traditional approach was proposed to fabricate the polymeric foam monolayer with designed density in a fixed volume by using the pre-mixture of expandable and expanded polymeric microballoons. After heating, the expandable microballoons expanded and bonded together to be integrated block with the final density from 0.1 g/cm3 to 0.5 g/cm3. The gradient density foams were fabricated by bonding with different monolayer. The microstructure and mechanical properties of each layer were investigated by SEM and compression strength tests. The results showed that the density of polymeric foams was matched with the design value very well by controlling the ratio of expandable and expanded polymeric microballoons. The uniform closed-cell structure with good bonding interface was shown from the SEM picture. And the mean cell size is less than 35μm. The polymeric foams exhibited ideal compressive behavior with the compressive strength as high as 9MPa. The Young's modulus and compressive strength nearly linear increased with the increasing of density. The extremely wide range of accessible densities should make this technology for broad application prospects.
A vacuum hot-pressed diffusion bonding method was used to prepare an Mg/Cu/Al laminated composite. Both the Mg/Cu and Al/Cu interfaces were investigated by means of scanning electron microscopy, electron probe microan...
A vacuum hot-pressed diffusion bonding method was used to prepare an Mg/Cu/Al laminated composite. Both the Mg/Cu and Al/Cu interfaces were investigated by means of scanning electron microscopy, electron probe microanalysis, X-ray diffraction spectrometer system and Vickers microhardness test. The results showed that two kinds of intermetallic compounds, Al4Cu9 adjacent to the Cu side and Al2Cu adjacent to the Al side, were formed in the interface of Al-Cu. Meanwhile, Mg2Cu was formed at the interface of Mg/Cu. The maximum value of shear strength is 13.1 MPa and the fracture of the joints had taken place at the Mg-Cu interface. The microhardness of the interface increased due to the formation of the intermetallic compounds, which is the main cause leading to poor bond properties.
A novel transparent conducting oxide based on the ATO/graphene multi-layered thin films has been developed to satisfy the application of transparent conductive electrode in solar cells. The ATO thin films are prepared...
A novel transparent conducting oxide based on the ATO/graphene multi-layered thin films has been developed to satisfy the application of transparent conductive electrode in solar cells. The ATO thin films are prepared by pulsed laser deposition method with high quality, namely the sheet resistance of 49.5 Ω/sq and average transmittance of 81.9 %. The prepared graphene sheet is well reduced and shows atomically thin, spotty distributed appearance on the top of the ATO thin films. The XRD and optical micrographs are used to confirm the successfully preparation of the ATO/graphene multi-layered thin films. The Hall measurements and UV-Vis spectrophotometer are conducted to evaluate the sheet resistance and optical transmittance of the innovative structure. It is found that graphene can improve the electrical properties of the ATO thin films with little influence on the optical transmittance.
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