Supercritical flows are ubiquitous in natural environments;however,there is rare 3D anatomy of their deposits.This study uses high-quality 3D seismic datasets from the world’s largest submarine fan,Bengal Fan,to inte...Supercritical flows are ubiquitous in natural environments;however,there is rare 3D anatomy of their deposits.This study uses high-quality 3D seismic datasets from the world’s largest submarine fan,Bengal Fan,to interpret 3D architectures and flow processes of Pliocene undulating bedforms that were related to supercritical flows.Bengal undulating bedforms as documented in this study were developed in unconfined settings,and are seismically imaged as strike-elongated,crescentic bedforms in plan view and as rhythmically undulating,upstream migrating,erosive,discontinuous reflections in section view.Their lee sides are overall 3 to 4 times steeper(0.280 to 1.19°in slope)and 3 to 4 times shorter(117 to 419 m in length)than their stoss flanks and were ascribed to faster(high flow velocities of 2.70 to 3.98 m/s)supercritical flows(Froude numbers of 1.53 to 2.27).Their stoss sides,in contrast,are overall 3 to 4 times gentler(0.120 to 0.270 in slope)and 3 to 4 times longer(410 to 1139 m in length)than their lee flanks and were related to slower(low velocities of 2.35 to 3.05 m/s)subcritical flows(Froude numbers of 0.58 to 0.97).Bengal wave-like features were,thus,created by supercriticalto-subcritical flow transformations through internal hydraulic jumps(i.e.,cyclic steps).They have crests that are positive relative to the surrounding region of the seafloor,suggesting the predominant deposition of draping sediments associated with net-depositional cyclic steps.Turbidity currents forming Bengal wave-like features were,thus,dominated by deposition,resulting in net-depositional cyclic steps.Sandy deposits associated with Bengal net-depositional cyclic steps are imaged themselves as closely spaced,strike-elongated high RMS-attribute patches,thereby showing closely spaced,long and linear,strike-elongated distribution patterns.展开更多
目前对土工格室加筋路堤研究主要集中在静载条件下,动载条件下研究的比较少。为研究分级循环荷载下土工格室加筋路堤的力学性能,采用USTX-2000的动力加载装置进行加载,对土工格室加筋路堤在不同加筋层数、格室高度、格室焊距等工况下进...目前对土工格室加筋路堤研究主要集中在静载条件下,动载条件下研究的比较少。为研究分级循环荷载下土工格室加筋路堤的力学性能,采用USTX-2000的动力加载装置进行加载,对土工格室加筋路堤在不同加筋层数、格室高度、格室焊距等工况下进行一系列模型试验。对分级循环荷载下路堤的竖向变形和坡面法向变形进行研究,并与固定振幅循环荷载及静载作用下的路堤进行对比分析,研究不同加载方案路堤力学性能的差异性。试验结果表明,土工格室加筋能显著提高路堤承受分级循环荷载的能力和减小竖向累积沉降量,在加筋间距一定的情况下,两层及以上加筋效果比单层加筋效果更显著,格室高度增大和格室焊距减小均可不同程度提高路堤承受分级循环荷载能力并减小竖向累积沉降量;加筋可减小路堤分级循环荷载下的坡面法向变形,格室高度增大和格室焊距减小在分级循环荷载幅值相同时均能减小坡顶和坡中处的法向累积变形;分级循环荷载作用下,当振次≥8 000或幅值≥80 k Pa时,路堤竖向累积沉降量超过固定振幅循环荷载,当振次≥9 000或振幅≥90 k Pa时,路堤坡顶法向累积变形超过固定振幅循环荷载;分级循环荷载作用下,路堤竖向和坡面法向累积变形均大于静载,加筋可有效减小分级循环荷载和静载作用下坡面法向累积变形差。展开更多
Adsorption behaviors of Cu2Zn2SOD on mercury electrodes were studied by the electrostatic capillary curve and the relationship between polarographic ultimate current and height of mercury column in the absence of the ...Adsorption behaviors of Cu2Zn2SOD on mercury electrodes were studied by the electrostatic capillary curve and the relationship between polarographic ultimate current and height of mercury column in the absence of the mediators. The effects of impure and denatured SOD on cyclic voltammogram were investigated, confirming that no denaturation was caused during adsorption on mercury electrodes. Double potential step chronocoulometry has confirmed that SOD adsorption on mercury electrode to be the absorption of monomolecular layer.展开更多
基金jointly funded by PetroChina Hangzhou Research Institute of Geology(No.2019D-4309)。
文摘Supercritical flows are ubiquitous in natural environments;however,there is rare 3D anatomy of their deposits.This study uses high-quality 3D seismic datasets from the world’s largest submarine fan,Bengal Fan,to interpret 3D architectures and flow processes of Pliocene undulating bedforms that were related to supercritical flows.Bengal undulating bedforms as documented in this study were developed in unconfined settings,and are seismically imaged as strike-elongated,crescentic bedforms in plan view and as rhythmically undulating,upstream migrating,erosive,discontinuous reflections in section view.Their lee sides are overall 3 to 4 times steeper(0.280 to 1.19°in slope)and 3 to 4 times shorter(117 to 419 m in length)than their stoss flanks and were ascribed to faster(high flow velocities of 2.70 to 3.98 m/s)supercritical flows(Froude numbers of 1.53 to 2.27).Their stoss sides,in contrast,are overall 3 to 4 times gentler(0.120 to 0.270 in slope)and 3 to 4 times longer(410 to 1139 m in length)than their lee flanks and were related to slower(low velocities of 2.35 to 3.05 m/s)subcritical flows(Froude numbers of 0.58 to 0.97).Bengal wave-like features were,thus,created by supercriticalto-subcritical flow transformations through internal hydraulic jumps(i.e.,cyclic steps).They have crests that are positive relative to the surrounding region of the seafloor,suggesting the predominant deposition of draping sediments associated with net-depositional cyclic steps.Turbidity currents forming Bengal wave-like features were,thus,dominated by deposition,resulting in net-depositional cyclic steps.Sandy deposits associated with Bengal net-depositional cyclic steps are imaged themselves as closely spaced,strike-elongated high RMS-attribute patches,thereby showing closely spaced,long and linear,strike-elongated distribution patterns.
文摘目前对土工格室加筋路堤研究主要集中在静载条件下,动载条件下研究的比较少。为研究分级循环荷载下土工格室加筋路堤的力学性能,采用USTX-2000的动力加载装置进行加载,对土工格室加筋路堤在不同加筋层数、格室高度、格室焊距等工况下进行一系列模型试验。对分级循环荷载下路堤的竖向变形和坡面法向变形进行研究,并与固定振幅循环荷载及静载作用下的路堤进行对比分析,研究不同加载方案路堤力学性能的差异性。试验结果表明,土工格室加筋能显著提高路堤承受分级循环荷载的能力和减小竖向累积沉降量,在加筋间距一定的情况下,两层及以上加筋效果比单层加筋效果更显著,格室高度增大和格室焊距减小均可不同程度提高路堤承受分级循环荷载能力并减小竖向累积沉降量;加筋可减小路堤分级循环荷载下的坡面法向变形,格室高度增大和格室焊距减小在分级循环荷载幅值相同时均能减小坡顶和坡中处的法向累积变形;分级循环荷载作用下,当振次≥8 000或幅值≥80 k Pa时,路堤竖向累积沉降量超过固定振幅循环荷载,当振次≥9 000或振幅≥90 k Pa时,路堤坡顶法向累积变形超过固定振幅循环荷载;分级循环荷载作用下,路堤竖向和坡面法向累积变形均大于静载,加筋可有效减小分级循环荷载和静载作用下坡面法向累积变形差。
文摘Adsorption behaviors of Cu2Zn2SOD on mercury electrodes were studied by the electrostatic capillary curve and the relationship between polarographic ultimate current and height of mercury column in the absence of the mediators. The effects of impure and denatured SOD on cyclic voltammogram were investigated, confirming that no denaturation was caused during adsorption on mercury electrodes. Double potential step chronocoulometry has confirmed that SOD adsorption on mercury electrode to be the absorption of monomolecular layer.
