The objective of the present paper is to develop nonlinear finite element method models for predicting the weld-induced initial deflection and residual stress of plating in steel stiffened-plate structures. For this p...The objective of the present paper is to develop nonlinear finite element method models for predicting the weld-induced initial deflection and residual stress of plating in steel stiffened-plate structures. For this purpose, three-dimensional thermo-elastic-plastic finite element method computations are performed with varying plate thickness and weld bead length (leg length) in welded plate panels, the latter being associated with weld heat input. The finite element models are verified by a comparison with experimental database which was obtained by the authors in separate studies with full scale measurements. It is concluded that the nonlinear finite element method models developed in the present paper are very accurate in terms of predicting the weld-induced initial imperfections of steel stiffened plate structures. Details of the numerical computations together with test database are documented.展开更多
The present paper has investigated the development of mesoscale and microscale disturbance superimposed on three-dimensional nonuniform flow, which extends the work of Zeng et al. The separating effect of the variatio...The present paper has investigated the development of mesoscale and microscale disturbance superimposed on three-dimensional nonuniform flow, which extends the work of Zeng et al. The separating effect of the variation of the horizontal and vertical scale of the disturbances has been found. Moreover, the propagating paths of the disturbances have also been discussed qualitatively.展开更多
A three-dimensional meso-γ,scale elastic atmospheric numerical model has been established and used to simulate a severe storm case.The important characteristics of the modeled storm are close to those of the observed...A three-dimensional meso-γ,scale elastic atmospheric numerical model has been established and used to simulate a severe storm case.The important characteristics of the modeled storm are close to those of the observed case.展开更多
Phase-change line memory cells with different line widths are fabricated using focused-ion-beam deposited C-Pt as a hard mask. The electrical performance of these memory devices was characterized. The current^oltage ...Phase-change line memory cells with different line widths are fabricated using focused-ion-beam deposited C-Pt as a hard mask. The electrical performance of these memory devices was characterized. The current^oltage （I-V） and resistance-voltage （RV） characteristics demonstrate that the power consumption decreases with the width of the phase-change line. A three-dimensional simulation is carried out to further study the scaling properties of the phase- change line memory. The results show that the resistive amorphous （RESET） power consumption is proportional to the cross-sectional area of the phase-change line, but increases as the line length decreases.展开更多
Numerical simulation of a heavy rainfall case in Henan area during 16-17 July 2004 is performed using the LASG （State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics） me...Numerical simulation of a heavy rainfall case in Henan area during 16-17 July 2004 is performed using the LASG （State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics） mesoscale model AREM （Advanced Regional Eta Model） developed by Yu （1989） and Yu et al. （1994）. The results are shown： the air in the middle part of troposphere within the horizontal range of meso-β scale convective system is heated by condensation latent heat. The isobaric surface in the middle and upper part of troposphere is rising, and thus meso-β scale high is formed; the isobaric surface in the lower part of troposphere is depressed, and thus meso-β high and low layer flow promotes the strong development scale low is formed. The interaction between the of the vertical motion. While the rising motion is developing strongly, obvious compensation sinking motion appears around it. In the south of rising motion region, the divergence current in the upper part of troposphere backflows towards south, which leads to the vertical circulation appearing in the upper part of troposphere. The sinking branch of the circulation integrates in the compensation sinking air current in the south of rising motion region and takes the horizontal momentum of upper air to the lower part of troposphere and forms a new meso-β scale jet. In the north of the rising motion region, a mesoscale vertical circulation develops in the low layer of troposphere. The divergence current of the sinking branch of the circulation, which flows southward, converges with warm and humid air current in the low layer of troposphere which flows from southwest, and forms a meso-β scale convergence line. Then it strengthens the convergence over the low level of heavy rain area. In the east of the rising motion region, a mesoscale vertical circulation also develops in low layer of troposphere. The divergence current of the sinking branch of the circulation, which flows westward, causes originally more consistent southwest air current in this region to the east deflection, and thus forms the cyclone curve in the southwest air current. The convergence is further strengthened in the meso-β scale convergence line. The strong development of ageostrophic vorticity in the lower part of troposphere is the important factor of the formation of the meso-β scale cyclone. At last the three-dimensional structure chart of development of heavy rain meso-β scale stream filed is given.展开更多
文摘The objective of the present paper is to develop nonlinear finite element method models for predicting the weld-induced initial deflection and residual stress of plating in steel stiffened-plate structures. For this purpose, three-dimensional thermo-elastic-plastic finite element method computations are performed with varying plate thickness and weld bead length (leg length) in welded plate panels, the latter being associated with weld heat input. The finite element models are verified by a comparison with experimental database which was obtained by the authors in separate studies with full scale measurements. It is concluded that the nonlinear finite element method models developed in the present paper are very accurate in terms of predicting the weld-induced initial imperfections of steel stiffened plate structures. Details of the numerical computations together with test database are documented.
文摘The present paper has investigated the development of mesoscale and microscale disturbance superimposed on three-dimensional nonuniform flow, which extends the work of Zeng et al. The separating effect of the variation of the horizontal and vertical scale of the disturbances has been found. Moreover, the propagating paths of the disturbances have also been discussed qualitatively.
文摘A three-dimensional meso-γ,scale elastic atmospheric numerical model has been established and used to simulate a severe storm case.The important characteristics of the modeled storm are close to those of the observed case.
基金Project supported by the National Integrate Circuit Research Program of China (Grant No. 2009ZX02023-003)the National Key Basic Research Program of China (Grant Nos. 2010CB934300, 2011CBA00602, and 2011CB932800)+1 种基金the National Natural Science Foundation of China (Grant Nos. 60906003, 60906004, 61006087, and 61076121)the Science and Technology Council of Shanghai of China (Grant No. 1052nm07000)
文摘Phase-change line memory cells with different line widths are fabricated using focused-ion-beam deposited C-Pt as a hard mask. The electrical performance of these memory devices was characterized. The current^oltage （I-V） and resistance-voltage （RV） characteristics demonstrate that the power consumption decreases with the width of the phase-change line. A three-dimensional simulation is carried out to further study the scaling properties of the phase- change line memory. The results show that the resistive amorphous （RESET） power consumption is proportional to the cross-sectional area of the phase-change line, but increases as the line length decreases.
基金Supported by the National Natural Science Foundation of China under Grant No.40575029the Commonweal Special Project "Study of flood-leading rainstorm forecast and warning system in South China" of the Ministry of Science and Technology.
文摘Numerical simulation of a heavy rainfall case in Henan area during 16-17 July 2004 is performed using the LASG （State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics） mesoscale model AREM （Advanced Regional Eta Model） developed by Yu （1989） and Yu et al. （1994）. The results are shown： the air in the middle part of troposphere within the horizontal range of meso-β scale convective system is heated by condensation latent heat. The isobaric surface in the middle and upper part of troposphere is rising, and thus meso-β scale high is formed; the isobaric surface in the lower part of troposphere is depressed, and thus meso-β high and low layer flow promotes the strong development scale low is formed. The interaction between the of the vertical motion. While the rising motion is developing strongly, obvious compensation sinking motion appears around it. In the south of rising motion region, the divergence current in the upper part of troposphere backflows towards south, which leads to the vertical circulation appearing in the upper part of troposphere. The sinking branch of the circulation integrates in the compensation sinking air current in the south of rising motion region and takes the horizontal momentum of upper air to the lower part of troposphere and forms a new meso-β scale jet. In the north of the rising motion region, a mesoscale vertical circulation develops in the low layer of troposphere. The divergence current of the sinking branch of the circulation, which flows southward, converges with warm and humid air current in the low layer of troposphere which flows from southwest, and forms a meso-β scale convergence line. Then it strengthens the convergence over the low level of heavy rain area. In the east of the rising motion region, a mesoscale vertical circulation also develops in low layer of troposphere. The divergence current of the sinking branch of the circulation, which flows westward, causes originally more consistent southwest air current in this region to the east deflection, and thus forms the cyclone curve in the southwest air current. The convergence is further strengthened in the meso-β scale convergence line. The strong development of ageostrophic vorticity in the lower part of troposphere is the important factor of the formation of the meso-β scale cyclone. At last the three-dimensional structure chart of development of heavy rain meso-β scale stream filed is given.
