This paper reviews the recent research progress in the hetero-nanostructure of silver nanoparticles on MOx (M=Mo, Ti and Si). It describes the general synthesis of hetero-nanostructure of silver nanoparticles on MOx, ...
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This paper reviews the recent research progress in the hetero-nanostructure of silver nanoparticles on MOx (M=Mo, Ti and Si). It describes the general synthesis of hetero-nanostructure of silver nanoparticles on MOx, and then outlines the interesting catalytic and sensing properties found in these hetero-nanostructures of silver nanoparticles on MOx.
In the present work, silicon nitride nanowires (SNNWs) have been synthesized via nitriding cryomilled nanocrystalline silicon powder. The silicon powder exhibits a fine polycrystalline structure after the cryomilling ...
In the present work, silicon nitride nanowires (SNNWs) have been synthesized via nitriding cryomilled nanocrystalline silicon powder. The silicon powder exhibits a fine polycrystalline structure after the cryomilling process, with an average grain size of 25 to 125 nm at various cryomilling times. The SNNWs that form after the nitridation of the cryomilled silicon powder exhibit single crystal structure and are 20 to 100 nm in diameter and ∼10 µm in length. The diameter of the nanowires is in agreement with the grain size of the cryomilled Si powder. Microstructural characterization reveals that the as-synthesized nanowires have a hexagonal structure and their primary growth direction is along the [0001] direction. The formation of the Si–N–Si bond during the cryomilling process, as investigated theoretically with density functional theory, promotes the subsequent synthesis of the α-Si3N4 nanowires. The mechanism for nanowire formation appears to be a vapor-solid (VS) reaction.
Structural characteristics, chemical bonds and thermoelectric properties of Si-doped boron carbides are studied through calculations of various structural unit models by using a self-consistent-field discrete variatio...
Structural characteristics, chemical bonds and thermoelectric properties of Si-doped boron carbides are studied through calculations of various structural unit models by using a self-consistent-field discrete variation Xα method. The calculations show that Si atom doped in boron carbide is in preference to substituting B or C atoms on the end of boron carbide chain, and then may occupy interstitial sites, but it is difficult for Si to substitute B or C atom in the centers of chain or in the icosahedra. A representative structural unit containing a Si atom is [C-B-Si]ε+ [B11C]ε-, while the structural unit without Si is [C-B-B(C)]δ--[B11C]δ+, and the coexistence of these two different structural units makes the electrical conductivity increases. As the covalent bond of Si-B or Si-C is weaker than that of B-B or B-C, the thermal conductivity decreases when Si is added into boron carbides. With the electrical conductivity increases and the thermal conductivity decreases, Si doping has significant effect on thermoelectric properties of boron carbides.
Aluminum oxynitride (AlON) is a nitrogen-stabilized defective spinel phase of alumina (y-Al2O3). Its structure has not been well understood so far. Solid-state27 Al magic-angle spinning nuclear magnetic resonance and ...
Aluminum oxynitride (AlON) is a nitrogen-stabilized defective spinel phase of alumina (y-Al2O3). Its structure has not been well understood so far. Solid-state27 Al magic-angle spinning nuclear magnetic resonance and quantum chemistry calculation are used to characterize y-Al2O3 and AMON ceramics in the present study. The resonance spectra clearly show different units (e.g. [AlN4], [AlO4] and [AlO6]) and vary with composition. The calculation shows that the vacancy located at octahedral site is more stable than that located at the tetrahedral site, and nitrogen atoms preferentially replace oxygen atoms in the tetrahedral site, which is in agreement with the experimental analysis by nuclear magnetic resonance.
Novel CoCrFeNiTiAlx(x:molar ratio, other elements are equimolar) high-entropy alloys were prepared by vacuum arc melting and these alloys were subsequently annealed at 1000°C for 2 h. The annealing effects on str...
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Novel CoCrFeNiTiAlx(x:molar ratio, other elements are equimolar) high-entropy alloys were prepared by vacuum arc melting and these alloys were subsequently annealed at 1000°C for 2 h. The annealing effects on structure and mechanical properties were investigated. Compared with the as-cast alloys, there are many complex intermetallic phases precipitated from the solid solution matrix in the as-annealed alloys with Al content lower than Al1.0. Only simple BCC solid solution structure appears in the as-annealed Al 1.5 and Al2.0 alloys. This kind of alloys exhibit high resistance to anneal softening. Most as-annealed alloys possess even higher Visker hardness than the as-cast ones. The as-annealed Al0.5 alloys shows the highest compressive strength while the Al0 alloy exhibits the best ductility, which is about 2.6 GPa and 13%, respectively. The CoCrFeNiTiAlx high-entropy alloys possess integrated high temperature mechanical property as well.
Superparamagnetic FePt nanoparticles (NPs) have attracted considerable attention due to their extremely promising potentials as the diagnostic and therapeutic reagent in biomedical *** the present study, we developed ...
Superparamagnetic FePt nanoparticles (NPs) have attracted considerable attention due to their extremely promising potentials as the diagnostic and therapeutic reagent in biomedical *** the present study, we developed a facile route to synthesize water-soluble FePtNPsabout 4 nm in diameter and oil-soluble FePtNPs about 6 nm in diameter using amino acids and oleic acid/oleylamine as the capping reagent, *** component, size and magnetic property of FePt NPs were tuned through adjusting the reactant molar ***, the anticancer activities of FePt NPs were evaluated using different brain tumor cell lines (such as U251, U87, H4) as the *** growth prohibition of tumor cells by NPs was measured through MTT assay, while the interaction of NPs and tumor cells was observed through transmission electron microscopy (TEM).The results show that FePt NPs synthesize by oleic acid/oleylamine shows better cytotoxicity toward brain tumor cells than L-cysteine-synthesized FePt *** cellular uptake, intracellular trafficking, and uptake pathways of FePt NRs in three cells were *** conclusion,we developed a facile synthesis of water-soluble superparamagnetic FePt NPs with the different component and the different anticancer activity of FePt NPs on Human brain tumor cells were *** results provide a promising potential of superparamagnetic FePt NPs as the multifunctional diagnostic and therapeutic reagent in biomedical fields.
作者：
Hongtao YuHua HaoHanxing LiuZhongqing Tianyuhongtao2001@***
Wuhan University of Technology State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Luoshi Road 122# Wuhan 430070 China People's Republic of 86-27-87864681 86-27-87651779 haohuayang@***
Wuhan University of Technology State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan 430070 China People's Republic of lhxhp@***
Wuhan University of Technology State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan 430070 China People's Republic of tzqmail@***
Chongqing Institute of Technology Chongqing 400050 China People's Republic of
The effect of CuO on the microstructure and microwave dielectric properties of the CaTiO3-Ca(Zn1/3Nb2/3)O3 ceramics prepared by the conventional solid-method has been investigated. Doped with the 0.5∼1.25wt% CuO powd...
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The effect of CuO on the microstructure and microwave dielectric properties of the CaTiO3-Ca(Zn1/3Nb2/3)O3 ceramics prepared by the conventional solid-method has been investigated. Doped with the 0.5∼1.25wt% CuO powder, the system of which the sintering temperatures were lowered exhibited the orthorhombic perovskite. It can effectively promote the microwave dielectric properties of the 0.3CaTiO3-0.7Ca(Zn1/3Nb2/3)O3 system at lower sintering temperature at the level of 1.0wt% CuO additive. The quality factor increases from 10860 to 13900GHz and not any significant change was observed in the TCF value with fixed CuO additive at different sintering temperature.
Spark plasma sintering (SPS) and Self-propagating High-temperature synthesis/ quick pressing (SHS/QP) methods were used to fabricate nanotubes reinforced alumina. The difference in microstructure was discussed. In the...
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Spark plasma sintering (SPS) and Self-propagating High-temperature synthesis/ quick pressing (SHS/QP) methods were used to fabricate nanotubes reinforced alumina. The difference in microstructure was discussed. In the SHS/QP process, the maximum densification temperature is 1660°C and the heating rate is about 1600°C /min. The whole densification process in SHS/QP is very short, which is much beneficial to protect the nanotubes and restrain the growing of grains. The fracture toughness of the sample prepared by SHS/QP is up to 4.9MPam1/2 for 1mass% CNTs/Al2O3 composites, which shows excellent toughening effects of nanotubes.
Graphene is considered to be an excellent fast saturable absorber (SA) with a broad operation bandwidth due to its ultrafast carrier dynamics and linear energy-momentum relation near the Dirac point [1]. Since Bao, Zh...
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ISBN:
(纸本)9781457705328
Graphene is considered to be an excellent fast saturable absorber (SA) with a broad operation bandwidth due to its ultrafast carrier dynamics and linear energy-momentum relation near the Dirac point [1]. Since Bao, Zhang, et al. employed it to successfully mode-lock a fiber laser for the first time [2], extensive efforts [3] have been devoted to developing this popular field, i.e., graphene-based ultrafast photonics.
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