The preparation of La0.4Sr0.6TiO3 （LSTO） buffer layer and YBa2Cu3O7-δ（YBCO） superconducting thick film by a low cost technology was studied. The crystal orientation of LSTO and YBCO films was detected by X-ray di...The preparation of La0.4Sr0.6TiO3 （LSTO） buffer layer and YBa2Cu3O7-δ（YBCO） superconducting thick film by a low cost technology was studied. The crystal orientation of LSTO and YBCO films was detected by X-ray diffraction, the conductivity of LSTO film and superconductivity of YBCO coating were investigated by standard four-probe method. Excellent in-plane alignment, smooth and dense LSTO buffer layer was successfully prepared on textured Ni-W taps by metal organic deposition （MOD）. YBCO thick film was fabricated by electrophoretic deposition （EPD）. The effects of applied voltage and deposition time on the YBCO coatings properties were studied. The results show that the critical current density of the YBCO coating deposited under 138 V for 35 min was about 600 A/cm2 （0 T, 77 K）.展开更多
Background To report quality control methods and baseline reproducibility data of the ultrasound measurements of carotid artery intima-media thickness in the project of Establishment of an Integrated System for Corona...Background To report quality control methods and baseline reproducibility data of the ultrasound measurements of carotid artery intima-media thickness in the project of Establishment of an Integrated System for Coronary Heart Disease Prevention and Treatment. Methods Standard ultrasound scanning and measuring protocols were established by the study group. All sonographers and readers were trained by the carotid ultrasound core lab and all digital ultrasound images were centrally read. Ten subjects were scanned twice （with 1 week interval） by 2 sonographers independently and images were read by a single reader to evaluate the sonographer variability. Twenty subjects＇ images were read twice （with 1 week interval） by a single reader to assess the reader variability and the reproducibility of IMT measured at different carotid segments. Results The intraclass correlation （ICC） of intra- and inter-sonographer and intra- reader for mean IMT measurements was 0.99, 0.98 and 0.97 respectively; while for max IMT, it was 0.97, 0.99 and 0.95 respectively. Among different carotid segments and sites, ICC for mean 1MT measurements of common carotid （CCA）, carotid artery bulb （Bulb）, internal carotid artery （ICA）, overall near wall and overall far wall was 0.97, 0.99, 0.89, 0.93 and 0.98 respectively. Conclusion The reproducibility of IMT measurements according to our protocol is acceptable, although better reproducibility is found when measuring the mean IMT than max IMT, CCA and Bulb IMT than ICA IMT, and far wall IMT than near wall IMT.展开更多
The surface quality of the substrate is a crucial factor in building ＂clean＂ quantum-dimensional systems. There are a number of micro-nano metric methods for the analysis state of surface： the atomic force microsco...The surface quality of the substrate is a crucial factor in building ＂clean＂ quantum-dimensional systems. There are a number of micro-nano metric methods for the analysis state of surface： the atomic force microscopy, the scanning tunneling microscopy and others. The SE （surface electron） over substrate has a ＂soft＂ hydrogen-like spectrum in the normal direction and the SEs mobility along is sensitive to the inhomogeneities of the substrate and this is analyzed in work. The values of electron mobility and energy of thermal activation are basic parameters of transport process which essentially depend on the helium film thickness. For analysis of nano-size inhomogeneities of substrate here we apply a new method providing a uniformity of the film thickness on substrate and fixing of measuring cell with supply wires. The plunger with electro-mechanic driver into a hermetic chamber is used for variation the helium level and consequently the film thickness. Considering values the conductivity and the variation of potential along surface is estimated the effective size of roughness from several nanometers （for non-saturated helium film） to 10^2 nm （for saturated film）.展开更多
We review recent studies by different experimental means of ultrathin films,exhibiting thickness-driven spin reorientation transitions(SRTs).The stage is set by determining,via phenomenological thermodynamic descripti...We review recent studies by different experimental means of ultrathin films,exhibiting thickness-driven spin reorientation transitions(SRTs).The stage is set by determining,via phenomenological thermodynamic description,of the relevant phase diagrams for the possible types of SRT with and without applied magnetic field.Suitable representation may be chosen such that best use is made of the linear character(under thickness variation) of the system's path in anisotropy space.The latter involves higher-order bulk and surface anisotropies in a substantial way.We examine sensitive experimental techniques for the detection and quantification of SRTs,such as hysteresis measurements with magneto-optical Kerr effect(MOKE),micromagnetic studies utilizing scanning electron microscopy with polarization analysis(SEMPA),photoemission electron microscopy(PEEM) and spin-polarized low-energy electron microscopy(SPLEEM) as well as ac magnetic susceptibility measurements via MOKE.Key issues are conclusively discussed including the identification of reliable experimental fingerprints about whether a given SRT proceeds via a phase of coexistence or via a cone(canted) phase.We demonstrate how the application of the general theoretical ideas to carefully designed measurements leads to the determination of the most important material parameters in any ultrathin-film SRT,namely,the surface(interface) magnetic anisotropy constants.The review concludes by our personal outline for future promising work on SRTs.展开更多
基金Project(N100602010)supported by the Fundamental Research Funds for the Central Universities of China
文摘The preparation of La0.4Sr0.6TiO3 （LSTO） buffer layer and YBa2Cu3O7-δ（YBCO） superconducting thick film by a low cost technology was studied. The crystal orientation of LSTO and YBCO films was detected by X-ray diffraction, the conductivity of LSTO film and superconductivity of YBCO coating were investigated by standard four-probe method. Excellent in-plane alignment, smooth and dense LSTO buffer layer was successfully prepared on textured Ni-W taps by metal organic deposition （MOD）. YBCO thick film was fabricated by electrophoretic deposition （EPD）. The effects of applied voltage and deposition time on the YBCO coatings properties were studied. The results show that the critical current density of the YBCO coating deposited under 138 V for 35 min was about 600 A/cm2 （0 T, 77 K）.
文摘Background To report quality control methods and baseline reproducibility data of the ultrasound measurements of carotid artery intima-media thickness in the project of Establishment of an Integrated System for Coronary Heart Disease Prevention and Treatment. Methods Standard ultrasound scanning and measuring protocols were established by the study group. All sonographers and readers were trained by the carotid ultrasound core lab and all digital ultrasound images were centrally read. Ten subjects were scanned twice （with 1 week interval） by 2 sonographers independently and images were read by a single reader to evaluate the sonographer variability. Twenty subjects＇ images were read twice （with 1 week interval） by a single reader to assess the reader variability and the reproducibility of IMT measured at different carotid segments. Results The intraclass correlation （ICC） of intra- and inter-sonographer and intra- reader for mean IMT measurements was 0.99, 0.98 and 0.97 respectively; while for max IMT, it was 0.97, 0.99 and 0.95 respectively. Among different carotid segments and sites, ICC for mean 1MT measurements of common carotid （CCA）, carotid artery bulb （Bulb）, internal carotid artery （ICA）, overall near wall and overall far wall was 0.97, 0.99, 0.89, 0.93 and 0.98 respectively. Conclusion The reproducibility of IMT measurements according to our protocol is acceptable, although better reproducibility is found when measuring the mean IMT than max IMT, CCA and Bulb IMT than ICA IMT, and far wall IMT than near wall IMT.
文摘The surface quality of the substrate is a crucial factor in building ＂clean＂ quantum-dimensional systems. There are a number of micro-nano metric methods for the analysis state of surface： the atomic force microscopy, the scanning tunneling microscopy and others. The SE （surface electron） over substrate has a ＂soft＂ hydrogen-like spectrum in the normal direction and the SEs mobility along is sensitive to the inhomogeneities of the substrate and this is analyzed in work. The values of electron mobility and energy of thermal activation are basic parameters of transport process which essentially depend on the helium film thickness. For analysis of nano-size inhomogeneities of substrate here we apply a new method providing a uniformity of the film thickness on substrate and fixing of measuring cell with supply wires. The plunger with electro-mechanic driver into a hermetic chamber is used for variation the helium level and consequently the film thickness. Considering values the conductivity and the variation of potential along surface is estimated the effective size of roughness from several nanometers （for non-saturated helium film） to 10^2 nm （for saturated film）.
基金supported by the State Key Programme for Basic Research of China (Grant No. 2010CB923401)National Natural Science Foundation of China (Grant Nos. 10834001,10974087 and 11023002)Natural Science Foundation of Jiangsu (Grant No. BK2012300)
文摘We review recent studies by different experimental means of ultrathin films,exhibiting thickness-driven spin reorientation transitions(SRTs).The stage is set by determining,via phenomenological thermodynamic description,of the relevant phase diagrams for the possible types of SRT with and without applied magnetic field.Suitable representation may be chosen such that best use is made of the linear character(under thickness variation) of the system's path in anisotropy space.The latter involves higher-order bulk and surface anisotropies in a substantial way.We examine sensitive experimental techniques for the detection and quantification of SRTs,such as hysteresis measurements with magneto-optical Kerr effect(MOKE),micromagnetic studies utilizing scanning electron microscopy with polarization analysis(SEMPA),photoemission electron microscopy(PEEM) and spin-polarized low-energy electron microscopy(SPLEEM) as well as ac magnetic susceptibility measurements via MOKE.Key issues are conclusively discussed including the identification of reliable experimental fingerprints about whether a given SRT proceeds via a phase of coexistence or via a cone(canted) phase.We demonstrate how the application of the general theoretical ideas to carefully designed measurements leads to the determination of the most important material parameters in any ultrathin-film SRT,namely,the surface(interface) magnetic anisotropy constants.The review concludes by our personal outline for future promising work on SRTs.
