Division of high resolution sequence stratigraphy units based on wavelet transform of logging data is found to be good at identifying subtle cycles of geological process in Kongnan area of Dagang Oilfield. The anal- y...Division of high resolution sequence stratigraphy units based on wavelet transform of logging data is found to be good at identifying subtle cycles of geological process in Kongnan area of Dagang Oilfield. The anal- ysis of multi-scales gyre of formation with 1-D continuous Dmey wavelet transform of log curve （GR） and I-D discrete Daubechies wavelet transform of log curve （Rt） all make the division of sequence interfaces more objec- tive and precise, which avoids the artificial influence with core analysis and the uncertainty with seismic data and core analysis.展开更多
Activities by various authors on aerodynamics and control dynamics of rotating stall in axial compressor are first traced. Then, a process of stall cell evolution in a subsonic stage is discussed based on a 2-D CFD. A...Activities by various authors on aerodynamics and control dynamics of rotating stall in axial compressor are first traced. Then, a process of stall cell evolution in a subsonic stage is discussed based on a 2-D CFD. A few numbers of vortices grow ahead of the rotor accumulating vorticity ejected from lightly stalled blades, and eventually organize a cell of circumferentially aligned huge vortices, which merge and recess repeatedly during the rotation. Such stall disturbance is intensified on trailing side of a circumferential inlet distortion and decays on the leading side. Considering these features, a new algorithm for stall warning is developed based on a correlation between pressure waveforms at each passing of a fixed blade. A remarkable change in the correlation level at near-stall provides a warning signal prior to the stall onset with sufficiently large time margin. This scheme is applied to achieve rotating stall prevention by actuating flaps installed on the hub. The last issue is on characteristics of forward swept blade which has much increased throttle margin with decreased tip loss. A 3-D computation shows that a secondary vortex generated in suction surface mid span interacts to reduce the tip leakage vortex that initiates the stall.展开更多
A novel layout has been proposed to reduce the single event upset(SEU) vulnerability of SRAM cells.Extensive 3-D technology computer-aided design(TCAD) simulation analyses show that the proposed layout can recover the...A novel layout has been proposed to reduce the single event upset(SEU) vulnerability of SRAM cells.Extensive 3-D technology computer-aided design(TCAD) simulation analyses show that the proposed layout can recover the upset-state much easier than conventional layout for larger space of PMOS transistors.For the angle incidence,the proposed layout is immune from ion hit in two plans,and is more robust against SEU in other two plans than the conventional one.The ability of anti-SEU is enhanced by at least 33% while the area cost reduced by 47%.Consequently,the layout strategy proposed can gain both reliability and area cost benefit simultaneously.展开更多
Four new 2D donor–acceptor conjugated polymers were designed and synthesized.These new polymers comprised fluorenealt-triphenylamine or carbazole-alt-triphenylamine as the backbones,and pendants with 2,1,3-benzothiad...Four new 2D donor–acceptor conjugated polymers were designed and synthesized.These new polymers comprised fluorenealt-triphenylamine or carbazole-alt-triphenylamine as the backbones,and pendants with 2,1,3-benzothiadiazole(BT)or naphtho[1,2-c:5,6-c]bis[1,2,5]thiadiazole(NT)in a triphenylamine unit as the side groups.By changing the acceptor BT for a stronger electron-withdrawing unit of NT moiety in the side chain,the energy levels,absorption spectra,band gaps,and charge-transport abilities of the resultant polymers could be effectively tuned.Bulk heterojunction solar cells with these polymers as the electron donors and(6,6)-phenyl-C71-butyric acid methyl ester as the electron acceptor exhibited high open-circuit voltage(more than 0.8 e V).The power conversion efficiency can be improved from 1.37%to 3.52%by replacing the BT with an NT moiety,which indicates that introducing NT as the side-chain building block can be an effective strategy to construct efficient 2D conjugated polymers for PSCs.展开更多
文摘Division of high resolution sequence stratigraphy units based on wavelet transform of logging data is found to be good at identifying subtle cycles of geological process in Kongnan area of Dagang Oilfield. The anal- ysis of multi-scales gyre of formation with 1-D continuous Dmey wavelet transform of log curve （GR） and I-D discrete Daubechies wavelet transform of log curve （Rt） all make the division of sequence interfaces more objec- tive and precise, which avoids the artificial influence with core analysis and the uncertainty with seismic data and core analysis.
文摘Activities by various authors on aerodynamics and control dynamics of rotating stall in axial compressor are first traced. Then, a process of stall cell evolution in a subsonic stage is discussed based on a 2-D CFD. A few numbers of vortices grow ahead of the rotor accumulating vorticity ejected from lightly stalled blades, and eventually organize a cell of circumferentially aligned huge vortices, which merge and recess repeatedly during the rotation. Such stall disturbance is intensified on trailing side of a circumferential inlet distortion and decays on the leading side. Considering these features, a new algorithm for stall warning is developed based on a correlation between pressure waveforms at each passing of a fixed blade. A remarkable change in the correlation level at near-stall provides a warning signal prior to the stall onset with sufficiently large time margin. This scheme is applied to achieve rotating stall prevention by actuating flaps installed on the hub. The last issue is on characteristics of forward swept blade which has much increased throttle margin with decreased tip loss. A 3-D computation shows that a secondary vortex generated in suction surface mid span interacts to reduce the tip leakage vortex that initiates the stall.
基金supported by the National Natural Science Foundation of China (Grant Nos. 60836004 and 60906014)Hunan Provincial Innovation Foundation For Postgraduate (Grant No. CX2011B026)
文摘A novel layout has been proposed to reduce the single event upset(SEU) vulnerability of SRAM cells.Extensive 3-D technology computer-aided design(TCAD) simulation analyses show that the proposed layout can recover the upset-state much easier than conventional layout for larger space of PMOS transistors.For the angle incidence,the proposed layout is immune from ion hit in two plans,and is more robust against SEU in other two plans than the conventional one.The ability of anti-SEU is enhanced by at least 33% while the area cost reduced by 47%.Consequently,the layout strategy proposed can gain both reliability and area cost benefit simultaneously.
基金financially supported by the National Basic Research Program of China(2014CB643501)the National Natural Science Foundation of China(21125419 and 51361165301)+1 种基金the Guangdong Natural Science Foundation(S2012030006232)the Research Fund for the Doctoral Program of Higher Education of China(20120172140001)
文摘Four new 2D donor–acceptor conjugated polymers were designed and synthesized.These new polymers comprised fluorenealt-triphenylamine or carbazole-alt-triphenylamine as the backbones,and pendants with 2,1,3-benzothiadiazole(BT)or naphtho[1,2-c:5,6-c]bis[1,2,5]thiadiazole(NT)in a triphenylamine unit as the side groups.By changing the acceptor BT for a stronger electron-withdrawing unit of NT moiety in the side chain,the energy levels,absorption spectra,band gaps,and charge-transport abilities of the resultant polymers could be effectively tuned.Bulk heterojunction solar cells with these polymers as the electron donors and(6,6)-phenyl-C71-butyric acid methyl ester as the electron acceptor exhibited high open-circuit voltage(more than 0.8 e V).The power conversion efficiency can be improved from 1.37%to 3.52%by replacing the BT with an NT moiety,which indicates that introducing NT as the side-chain building block can be an effective strategy to construct efficient 2D conjugated polymers for PSCs.
