High quality GdBa2Cu307-y （Gd123） textured bulks with Nd2BaCuO5 （Nd211） nanoparticle precipitations have been fabricated by a nanoparticle-powders-assisted MTG （melt-textured-growth） technique. The high density ...High quality GdBa2Cu307-y （Gd123） textured bulks with Nd2BaCuO5 （Nd211） nanoparticle precipitations have been fabricated by a nanoparticle-powders-assisted MTG （melt-textured-growth） technique. The high density nanoscale flux pinning sites were introduced into Gd123 by mixing Nd211 nanoparticle powders （about 20-50 nm） with Gd123 nano-precursors before the MTG process. Microstructural analyses reveal that a large number of Nd211 nanoparticles with a size around 50-150 nm were inserted in the Gd123 matrix, forming a kind of superconducting nanocomposites. The critical current density at 77 K is systematically increased and the flux pinning behavior is significantly improved. The scaling behavior of the flux pinning force shows a magnetic field dependent feature with a peak located at hp≈0.4. This may be the fingerprint of melt-textured 123 compounds, which cannot be interpreted by the simple superposition of different types of elementary pinning sources.展开更多
It was found that silver nanoparticles could strongly enhance the chemiluminescence (CL) of the luminol-KIO4 system in the presence of Co2+. The most intensive CL signals were obtained with silver nanoparticles in dia...It was found that silver nanoparticles could strongly enhance the chemiluminescence (CL) of the luminol-KIO4 system in the presence of Co2+. The most intensive CL signals were obtained with silver nanoparticles in diameter of 22 nm. The studies of UV-visible spectra and CL spectra were carried out to explore the possible CL enhancement mechanism. Moreover, the influences of 17 amino acids and 25 organic compounds on the luminol-KIO4-Co2+-Ag NPs CL system were studied by a flow injection procedure, which led to an effective method to detect these compounds.展开更多
The effect of magnetic field on the growth behavior of compound layer was examined at the interface between the solid Cu and liquid AI during reactive diffusion. It was found that the thickness of compound layer was r...The effect of magnetic field on the growth behavior of compound layer was examined at the interface between the solid Cu and liquid AI during reactive diffusion. It was found that the thickness of compound layer was reduced by the high magnetic field. The growth activation energy in β, γ1 and ε2 layers under a high magnetic field was larger than those in non magnetic circumstances, the increment percentage being 4.8%, 13.3% and 5.5%, respectively.展开更多
基金supported in part by the National Natural Science Foundation of China (No. 50872116)the Fundamental Research Funds for the Central Universities of China (No. SWJTU09ZT24)+1 种基金the PCSIRT of the Ministry of Education of China (No.IRT0751)the Specialized Research Fund for the Doctoral Program of Higher Education of China (No. 200806130023)
文摘High quality GdBa2Cu307-y （Gd123） textured bulks with Nd2BaCuO5 （Nd211） nanoparticle precipitations have been fabricated by a nanoparticle-powders-assisted MTG （melt-textured-growth） technique. The high density nanoscale flux pinning sites were introduced into Gd123 by mixing Nd211 nanoparticle powders （about 20-50 nm） with Gd123 nano-precursors before the MTG process. Microstructural analyses reveal that a large number of Nd211 nanoparticles with a size around 50-150 nm were inserted in the Gd123 matrix, forming a kind of superconducting nanocomposites. The critical current density at 77 K is systematically increased and the flux pinning behavior is significantly improved. The scaling behavior of the flux pinning force shows a magnetic field dependent feature with a peak located at hp≈0.4. This may be the fingerprint of melt-textured 123 compounds, which cannot be interpreted by the simple superposition of different types of elementary pinning sources.
文摘It was found that silver nanoparticles could strongly enhance the chemiluminescence (CL) of the luminol-KIO4 system in the presence of Co2+. The most intensive CL signals were obtained with silver nanoparticles in diameter of 22 nm. The studies of UV-visible spectra and CL spectra were carried out to explore the possible CL enhancement mechanism. Moreover, the influences of 17 amino acids and 25 organic compounds on the luminol-KIO4-Co2+-Ag NPs CL system were studied by a flow injection procedure, which led to an effective method to detect these compounds.
基金supported by the National Natural Science Foundation of China (No. 50871026)the 111 Project(B07015)+2 种基金Foundation for the Author of National Excellent Doctoral Dissertation of China (No. 200745)Program for New Century Excellent Talents in University (NCET-06-0288)the Fundamental Research Funds for the Central Universities (N090109001)
文摘The effect of magnetic field on the growth behavior of compound layer was examined at the interface between the solid Cu and liquid AI during reactive diffusion. It was found that the thickness of compound layer was reduced by the high magnetic field. The growth activation energy in β, γ1 and ε2 layers under a high magnetic field was larger than those in non magnetic circumstances, the increment percentage being 4.8%, 13.3% and 5.5%, respectively.
