Geode, boudinage, and undulation structures are widely distributed in the siliceous beds of the Upper Cretaceous/Tertiary rocks in Jordan. Their formation was attributed to tectonic forces, syngenetic processes, organ...Geode, boudinage, and undulation structures are widely distributed in the siliceous beds of the Upper Cretaceous/Tertiary rocks in Jordan. Their formation was attributed to tectonic forces, syngenetic processes, organic disintegration processes, subaquatic gliding, compaction and settlement, and meteoritic impacts. In this work, the structural features in the siliceous beds of Jordan are attributed to an interplay of load and directed pressures, and mineralogical transformation processes (opal-A to opal-CT to quartz), governed by pH changes. Tectonic directed pressure was acting in an ESE-WSW direction and is common in the silicified limestone of Upper Cretaceous.展开更多
The geoid undulations in the Northwest Pacific were calculated by usingtheTopex/Poseidon and Geosataltimeter data. Firstly the bias between two types of the altimeter data was removed and the geoid undulations in the...The geoid undulations in the Northwest Pacific were calculated by usingtheTopex/Poseidon and Geosataltimeter data. Firstly the bias between two types of the altimeter data was removed and the geoid undulations in theNorthwest Pacific were acquired by a long wave bias diminishing model with a resolution of 30 km and precision of 14cm. Then an algorithm of inversion of gravity anomalies was derived , and the gravity anomalies in the East China Seawere calculated by using the algorithm and the geoid undulations. The rms of difference between the in situ measure-ments the gravity anomalies from altimeter data was 3 .8× 10-5 m/s2. A method to colculate the gravity anomaliesin a larger area was developed which combined gravity anomalies in four subregions overlapping each other into one data set in a larger region. The error analysys shaws that the model and result of the inversion of gravity anomalies were reliable.展开更多
The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory. In a two-layer fluid with the upper layer having a free surface, there exist two modes of...The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory. In a two-layer fluid with the upper layer having a free surface, there exist two modes of waves propagating at both the free surface of the upper layer and the interface between the two layers. Due to a wave train of a particular mode incident on an obstacle which is bottom-standing on the lower layer, reflected and transmitted waves of both modes are created by the obstacle. For small undulations on the bottom of the lower layer, a perturbation method is employed to obtain first-order reflection and transmission coefficients of both modes for incident wave trains of again both modes in terms of integrals involving the bed-shape fimction. For sinusoidal undulations, numerical results are presented graphically to illustrate the energy transfer between the waves of different modes by the undulating bed.展开更多
The scattering of plane surface waves by bottom undulations in channel flow consisting of two layers is investigated by assuming that the bed of the channel is composed of porous material. The upper surface of the flu...The scattering of plane surface waves by bottom undulations in channel flow consisting of two layers is investigated by assuming that the bed of the channel is composed of porous material. The upper surface of the fluid is bounded by a rigid lid and the channel is unbounded in the horizontal directions. There exists only one wave mode corresponding to an internal wave. For small undulations, a simplified perturbation analysis is used to obtain first order reflection and transmission coefficients in terms of integrals involving the shape function describing the bottom. For sinusoidal bottom undulations and exponentially decaying bottom topography, the first order coefficients are computed. In the case of sinusoidal bottom the first order transmission coefficient is found to vanish identically. The numerical results are depicted graphically in a number of figures.展开更多
In this paper, the complete Bouguer anomaly data from Cameroon and part of the neighboring countries has been examined to compute the topography of the Moho undulations. This work is based on an improved filtering tec...In this paper, the complete Bouguer anomaly data from Cameroon and part of the neighboring countries has been examined to compute the topography of the Moho undulations. This work is based on an improved filtering technique and an appropriate density contrast between the crust and the upper mantle. Comparison with seismic data shows that our Moho map defines better the continuity and morphology of the crust-mantle interface than the scattered seismic data in Cameroon. The present relief map, although may not give real depths at some areas provides a better surface correlation with the surface geology better than seismic techniques. Comparison between the Moho undulations and the topography maps reveals that the crust in Cameroon seems to not be in isostatic equilibrium. The Moho in the Central African Shear Zone (CASZ) must be linked with different dextral movements during the opening of the south Atlantic in the Cretaceous time. In the Chad basin, the Moho is associated to the opening of the central and south Atlantic ~130 Ma. In the case of the Congo basin, the Moho undulations are related to the post rift subsidence. The correlation between the Moho undulations map with the surface geology indicates that the actual morphology of the crust mantle interface in Cameroon can be related to the build-up of the West and Central African rift system dating back to the Early Cretaceous to Palaeogene, where the presence of intraplate tensional stresses reactivated previous shear zones of lithospheric weakness during the break up of Gondwana.展开更多
A computational framework was developed to capture the combined fluid-and solid-like behavior of lipid membranes in a unified manner.Specifically,the in-plane diffusion of lipid molecules and the associated evolution ...A computational framework was developed to capture the combined fluid-and solid-like behavior of lipid membranes in a unified manner.Specifically,the in-plane diffusion of lipid molecules and the associated evolution of membrane tension were explicitly taken into account in the model.In addition,the out-of-plane movement induced bending and shearing of membrane,along with its thermal undulations caused by bombardment of medium molecules,were also considered.The capability and validity of this approach were demonstrated by simulating the enforced deformation and shape fluctuations of a lipid vesicle under a variety of testing conditions as well as their comparison with corresponding theoretical predictions.Our model could serve a useful platform for investigating processes such as cell spreading and division where morphology evolution of the membrane and transport of lipids/transmembrane proteins are known to play key roles.展开更多
WHEN Sammia Du took her first step on stage in a Cairo five-star hotel, the public looked a bit ambivalent. Her Asian features were unlike those of any other Egyptian belly dancers who performed that night, But as she...WHEN Sammia Du took her first step on stage in a Cairo five-star hotel, the public looked a bit ambivalent. Her Asian features were unlike those of any other Egyptian belly dancers who performed that night, But as she closed her eyes and began to ripple to the rhythm of the drums, the young Chinese dancer was quick to dispel any doubts.展开更多
In this paper our interest is focussed on the behavior in the transition of the Traveling Wave (TW) convective patterns along the nonlinear branch in a rectangular cell of Γ=12 for ψ=-0.11. Our numerical simulations...In this paper our interest is focussed on the behavior in the transition of the Traveling Wave (TW) convective patterns along the nonlinear branch in a rectangular cell of Γ=12 for ψ=-0.11. Our numerical simulations were performed by solving the two-dimensional hydrodynamic equations using the SIMPLE method. Three types of convection patterns appearing in the nonlinear branch of the bifurcation diagram were observed. In particular, the undulation TW state in the rectangular cell was obtained, and the hysteresis in the transition from the TW State to the Stationary Overturning Convection (SOC) was verified.展开更多
文摘Geode, boudinage, and undulation structures are widely distributed in the siliceous beds of the Upper Cretaceous/Tertiary rocks in Jordan. Their formation was attributed to tectonic forces, syngenetic processes, organic disintegration processes, subaquatic gliding, compaction and settlement, and meteoritic impacts. In this work, the structural features in the siliceous beds of Jordan are attributed to an interplay of load and directed pressures, and mineralogical transformation processes (opal-A to opal-CT to quartz), governed by pH changes. Tectonic directed pressure was acting in an ESE-WSW direction and is common in the silicified limestone of Upper Cretaceous.
文摘The geoid undulations in the Northwest Pacific were calculated by usingtheTopex/Poseidon and Geosataltimeter data. Firstly the bias between two types of the altimeter data was removed and the geoid undulations in theNorthwest Pacific were acquired by a long wave bias diminishing model with a resolution of 30 km and precision of 14cm. Then an algorithm of inversion of gravity anomalies was derived , and the gravity anomalies in the East China Seawere calculated by using the algorithm and the geoid undulations. The rms of difference between the in situ measure-ments the gravity anomalies from altimeter data was 3 .8× 10-5 m/s2. A method to colculate the gravity anomaliesin a larger area was developed which combined gravity anomalies in four subregions overlapping each other into one data set in a larger region. The error analysys shaws that the model and result of the inversion of gravity anomalies were reliable.
文摘The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory. In a two-layer fluid with the upper layer having a free surface, there exist two modes of waves propagating at both the free surface of the upper layer and the interface between the two layers. Due to a wave train of a particular mode incident on an obstacle which is bottom-standing on the lower layer, reflected and transmitted waves of both modes are created by the obstacle. For small undulations on the bottom of the lower layer, a perturbation method is employed to obtain first-order reflection and transmission coefficients of both modes for incident wave trains of again both modes in terms of integrals involving the bed-shape fimction. For sinusoidal undulations, numerical results are presented graphically to illustrate the energy transfer between the waves of different modes by the undulating bed.
文摘The scattering of plane surface waves by bottom undulations in channel flow consisting of two layers is investigated by assuming that the bed of the channel is composed of porous material. The upper surface of the fluid is bounded by a rigid lid and the channel is unbounded in the horizontal directions. There exists only one wave mode corresponding to an internal wave. For small undulations, a simplified perturbation analysis is used to obtain first order reflection and transmission coefficients in terms of integrals involving the shape function describing the bottom. For sinusoidal bottom undulations and exponentially decaying bottom topography, the first order coefficients are computed. In the case of sinusoidal bottom the first order transmission coefficient is found to vanish identically. The numerical results are depicted graphically in a number of figures.
文摘In this paper, the complete Bouguer anomaly data from Cameroon and part of the neighboring countries has been examined to compute the topography of the Moho undulations. This work is based on an improved filtering technique and an appropriate density contrast between the crust and the upper mantle. Comparison with seismic data shows that our Moho map defines better the continuity and morphology of the crust-mantle interface than the scattered seismic data in Cameroon. The present relief map, although may not give real depths at some areas provides a better surface correlation with the surface geology better than seismic techniques. Comparison between the Moho undulations and the topography maps reveals that the crust in Cameroon seems to not be in isostatic equilibrium. The Moho in the Central African Shear Zone (CASZ) must be linked with different dextral movements during the opening of the south Atlantic in the Cretaceous time. In the Chad basin, the Moho is associated to the opening of the central and south Atlantic ~130 Ma. In the case of the Congo basin, the Moho undulations are related to the post rift subsidence. The correlation between the Moho undulations map with the surface geology indicates that the actual morphology of the crust mantle interface in Cameroon can be related to the build-up of the West and Central African rift system dating back to the Early Cretaceous to Palaeogene, where the presence of intraplate tensional stresses reactivated previous shear zones of lithospheric weakness during the break up of Gondwana.
基金funded by the Research Grants Council of the Hong Kong Special Administration Region(Grants GRF/17257016 and GRF/17210618)the National Natural Science Foundation of China(Grant 11872325).
文摘A computational framework was developed to capture the combined fluid-and solid-like behavior of lipid membranes in a unified manner.Specifically,the in-plane diffusion of lipid molecules and the associated evolution of membrane tension were explicitly taken into account in the model.In addition,the out-of-plane movement induced bending and shearing of membrane,along with its thermal undulations caused by bombardment of medium molecules,were also considered.The capability and validity of this approach were demonstrated by simulating the enforced deformation and shape fluctuations of a lipid vesicle under a variety of testing conditions as well as their comparison with corresponding theoretical predictions.Our model could serve a useful platform for investigating processes such as cell spreading and division where morphology evolution of the membrane and transport of lipids/transmembrane proteins are known to play key roles.
文摘WHEN Sammia Du took her first step on stage in a Cairo five-star hotel, the public looked a bit ambivalent. Her Asian features were unlike those of any other Egyptian belly dancers who performed that night, But as she closed her eyes and began to ripple to the rhythm of the drums, the young Chinese dancer was quick to dispel any doubts.
文摘In this paper our interest is focussed on the behavior in the transition of the Traveling Wave (TW) convective patterns along the nonlinear branch in a rectangular cell of Γ=12 for ψ=-0.11. Our numerical simulations were performed by solving the two-dimensional hydrodynamic equations using the SIMPLE method. Three types of convection patterns appearing in the nonlinear branch of the bifurcation diagram were observed. In particular, the undulation TW state in the rectangular cell was obtained, and the hysteresis in the transition from the TW State to the Stationary Overturning Convection (SOC) was verified.
