The bonding of solid steel plate to liquid aluminum was studied using rapidsolidification. The surface of solid steel plate was defatted, descaled, immersed (in K_2ZrF_6 fluxaqueous solution) and stoved. In order to d...The bonding of solid steel plate to liquid aluminum was studied using rapidsolidification. The surface of solid steel plate was defatted, descaled, immersed (in K_2ZrF_6 fluxaqueous solution) and stoved. In order to determine the thickness of Fe-Al compound layer at theinterface of steel-aluminum solid to liquid bonding under rapid solidification, the interface ofbonding plate was investigated by SEM (Scanning Electron Microscope) experiment. The relationshipbetween bonding parameters (such as preheat temperature of steel plate, temperature of aluminumliquid and bonding time) and thickness of Fe-Al compound layer at the interface was established byartificial neural networks (ANN) perfectly. The maximum of relative error between the output and thedesired output of the ANN is only 5.4%. From the bonding parameters for the largest interfacialshear strength of bonding plate (226℃ for preheat temperature of steel plate, 723℃ for temperatureof aluminum liquid and 15.8 s for bonding time), the reasonable thickness of Fe-Al compound layer10.8 μm was got.展开更多
The non-axisymmetrical vibration of elastic circular plate resting on a layered transversely isotropic saturated ground was studied. First, the 3-d dynamic equations in cylindrical coordinate for transversely isotropi...The non-axisymmetrical vibration of elastic circular plate resting on a layered transversely isotropic saturated ground was studied. First, the 3-d dynamic equations in cylindrical coordinate for transversely isotropic saturated soils were transformed into a group of governing differential equations with 1-order by the technique of Fourier expanding with respect to azimuth, and the state equation is established by Hankel integral transform method, furthermore the transfer matrixes within layered media are derived based on the solutions of the state equation. Secondly, by the transfer matrixes, the general solutions of dynamic response for layered transversely isotropic saturated ground excited by an arbitrary harmonic force were established under the boundary conditions, drainage conditions on the surface of ground as well as the contact conditions. Thirdly, the problem was led to a pair of dual integral equations describing the mixed boundaryvalue problem which can be reduced to the Fredholm integral equations of the second kind solved by numerical procedure easily. At the end of this paper, a numerical result concerning vertical and radical displacements both the surface of saturated ground and plate is evaluated.展开更多
Examining the retinal tissue has the potential to provide a unique method and technique to quantify Alzheimer’s disease-related changes in participants at various stages of the disease.In this metaanalysis,we aimed t...Examining the retinal tissue has the potential to provide a unique method and technique to quantify Alzheimer’s disease-related changes in participants at various stages of the disease.In this metaanalysis,we aimed to investigate the association of various optical coherence tomography parameters with Alzheimer’s disease and whether retinal measurements can be used to diffe rentiate between Alzheimer’s disease and control subjects.Scientific databases including Google Schola r,Web of Science,and PubMed were systematically searched for published articles that evaluated retinal nerve fiber layer thickness and retinal microvascular network in Alzheimer’s disease and control subjects.Seventy-three studies(5850 participants,including 2249 Alzheimer’s disease patients and 3601controls) were included in this meta-analysis.Relative to controls,Alzheimer’s disease patients had a significantly lower global retinal nerve fiber layer thickness(standardized mean difference [SMD]=-0.79,95% confidence intervals [CI]:-1.03 to-0.54,P <0.00001) as well as each quadrant being thinner in Alzheimer’s disease versus controls.Regarding macular paramete rs,values measured by optical coherence tomography were significantly lower in Alzheimer’s disease than controls for macular thickness(pooled SMD:-0.44,95% CI:-0.67 to-0.20,P=0.0003),foveal thickness(pooled SMD=-0.39,95% CI:-0.58 to-0.19,P <0.0001),ganglion cell inner plexiform layer(SMD=-1.26,95% CI:-2.24 to-0.27,P=0.01) and macular volume(pooled SMD=-0.41,95% CI-0.76 to-0.07,P=0.02).Analysis using optical coherence tomography angiography parameters revealed mixed results between Alzheimer’s disease and controls.Superficial vessel density(pooled SMD=-0.42,95% CI:-0.68 to-0.17,P=0.0001) and deep vessel density(pooled SMD=-0.46,95% CI:-0.75 to-0.18,P=0.001) were found to be thinner in Alzheimer’s disease patients whereas the foveal avascular zone(SMD=0.84,95% CI:0.17-1.51,P=0.01) was larger in controls.Vascular density and thickness of various retinal laye rs were decreased in Alzheimer’s disease patients compared to controls.Our results provide evidence for optical coherence tomography technology having the potential to detect retinal and microvascular changes in patients diagnosed with Alzheimer’s disease and aid in monito ring and early diagnosis methods.展开更多
In this study, CrN/Cr2O3 double-layered coatings with various thickness ratios of CrN vs Cr2O3 layer were prepared by arc ion plating technology. The influences of the thickness ratio of CrN vs Cr2O3 layer on the micr...In this study, CrN/Cr2O3 double-layered coatings with various thickness ratios of CrN vs Cr2O3 layer were prepared by arc ion plating technology. The influences of the thickness ratio of CrN vs Cr2O3 layer on the microstructural characteristics as well as the mechanical and tribological properties of the CrN/Cr2O3 doublelayered coatings were investigated. The corresponding mechanisms were also discussed. The results indicated that the insertion of CrN layer between the Cr2O3 layer and substrate can effectively decrease the internal stress level of the coating. With increasing the thickness ratio of CrN vs Cr2O3 layer, the surface roughness of double-layered coatings decreased gradually, which had a certain influence on the friction coefficient. In addition, the microhardness also declined gradually, the adhesive strength almost increased linearly, whereas the wear rate declined firstly and then increased slightly. As the thickness ratio was 2：1, the double-layered coating exhibited the best wear resistance.展开更多
基金This project is financially supported by National Natural Science Foundation of China (No.50274047) and Advanced Technical Committee of China(No. 715-009-060)
文摘The bonding of solid steel plate to liquid aluminum was studied using rapidsolidification. The surface of solid steel plate was defatted, descaled, immersed (in K_2ZrF_6 fluxaqueous solution) and stoved. In order to determine the thickness of Fe-Al compound layer at theinterface of steel-aluminum solid to liquid bonding under rapid solidification, the interface ofbonding plate was investigated by SEM (Scanning Electron Microscope) experiment. The relationshipbetween bonding parameters (such as preheat temperature of steel plate, temperature of aluminumliquid and bonding time) and thickness of Fe-Al compound layer at the interface was established byartificial neural networks (ANN) perfectly. The maximum of relative error between the output and thedesired output of the ANN is only 5.4%. From the bonding parameters for the largest interfacialshear strength of bonding plate (226℃ for preheat temperature of steel plate, 723℃ for temperatureof aluminum liquid and 15.8 s for bonding time), the reasonable thickness of Fe-Al compound layer10.8 μm was got.
基金Project supported by the National Natural Science Foundation of China(No.50678108)the Natural Science Foundation of Zhejiang Province(No.Y106264 )
文摘The non-axisymmetrical vibration of elastic circular plate resting on a layered transversely isotropic saturated ground was studied. First, the 3-d dynamic equations in cylindrical coordinate for transversely isotropic saturated soils were transformed into a group of governing differential equations with 1-order by the technique of Fourier expanding with respect to azimuth, and the state equation is established by Hankel integral transform method, furthermore the transfer matrixes within layered media are derived based on the solutions of the state equation. Secondly, by the transfer matrixes, the general solutions of dynamic response for layered transversely isotropic saturated ground excited by an arbitrary harmonic force were established under the boundary conditions, drainage conditions on the surface of ground as well as the contact conditions. Thirdly, the problem was led to a pair of dual integral equations describing the mixed boundaryvalue problem which can be reduced to the Fredholm integral equations of the second kind solved by numerical procedure easily. At the end of this paper, a numerical result concerning vertical and radical displacements both the surface of saturated ground and plate is evaluated.
基金National Health and Medical Research Council (NHMRC) Australia (to VG)。
文摘Examining the retinal tissue has the potential to provide a unique method and technique to quantify Alzheimer’s disease-related changes in participants at various stages of the disease.In this metaanalysis,we aimed to investigate the association of various optical coherence tomography parameters with Alzheimer’s disease and whether retinal measurements can be used to diffe rentiate between Alzheimer’s disease and control subjects.Scientific databases including Google Schola r,Web of Science,and PubMed were systematically searched for published articles that evaluated retinal nerve fiber layer thickness and retinal microvascular network in Alzheimer’s disease and control subjects.Seventy-three studies(5850 participants,including 2249 Alzheimer’s disease patients and 3601controls) were included in this meta-analysis.Relative to controls,Alzheimer’s disease patients had a significantly lower global retinal nerve fiber layer thickness(standardized mean difference [SMD]=-0.79,95% confidence intervals [CI]:-1.03 to-0.54,P <0.00001) as well as each quadrant being thinner in Alzheimer’s disease versus controls.Regarding macular paramete rs,values measured by optical coherence tomography were significantly lower in Alzheimer’s disease than controls for macular thickness(pooled SMD:-0.44,95% CI:-0.67 to-0.20,P=0.0003),foveal thickness(pooled SMD=-0.39,95% CI:-0.58 to-0.19,P <0.0001),ganglion cell inner plexiform layer(SMD=-1.26,95% CI:-2.24 to-0.27,P=0.01) and macular volume(pooled SMD=-0.41,95% CI-0.76 to-0.07,P=0.02).Analysis using optical coherence tomography angiography parameters revealed mixed results between Alzheimer’s disease and controls.Superficial vessel density(pooled SMD=-0.42,95% CI:-0.68 to-0.17,P=0.0001) and deep vessel density(pooled SMD=-0.46,95% CI:-0.75 to-0.18,P=0.001) were found to be thinner in Alzheimer’s disease patients whereas the foveal avascular zone(SMD=0.84,95% CI:0.17-1.51,P=0.01) was larger in controls.Vascular density and thickness of various retinal laye rs were decreased in Alzheimer’s disease patients compared to controls.Our results provide evidence for optical coherence tomography technology having the potential to detect retinal and microvascular changes in patients diagnosed with Alzheimer’s disease and aid in monito ring and early diagnosis methods.
基金the National Key Basic Research Program of China("973 Program",No.2012CB625100)the National Natural Science Foundation of China(No.51001106&No.51301181)the Doctoral Starting up Foundation of Liaoning Province Science and Technology Agency,China(No.20131118)
文摘In this study, CrN/Cr2O3 double-layered coatings with various thickness ratios of CrN vs Cr2O3 layer were prepared by arc ion plating technology. The influences of the thickness ratio of CrN vs Cr2O3 layer on the microstructural characteristics as well as the mechanical and tribological properties of the CrN/Cr2O3 doublelayered coatings were investigated. The corresponding mechanisms were also discussed. The results indicated that the insertion of CrN layer between the Cr2O3 layer and substrate can effectively decrease the internal stress level of the coating. With increasing the thickness ratio of CrN vs Cr2O3 layer, the surface roughness of double-layered coatings decreased gradually, which had a certain influence on the friction coefficient. In addition, the microhardness also declined gradually, the adhesive strength almost increased linearly, whereas the wear rate declined firstly and then increased slightly. As the thickness ratio was 2：1, the double-layered coating exhibited the best wear resistance.
