Understanding fingering, as a challenge to stable displacement during the immiscible flow, has become a crucial phenomenon for geological carbon sequestration, enhanced oil recovery, and groundwater protection. Typica...Understanding fingering, as a challenge to stable displacement during the immiscible flow, has become a crucial phenomenon for geological carbon sequestration, enhanced oil recovery, and groundwater protection. Typically governed by gravity, viscous and capillary forces, these factors lead invasive fluids to occupy pore space irregularly and incompletely. Previous studies have demonstrated capillary numbers,describing the viscous and capillary forces, to quantificationally induce evolution of invasion patterns.While the evolution mechanisms of invasive patterns have not been deeply elucidated under the constant capillary number and three variable parameters including velocity, viscosity, and interfacial tension.Our research employs two horizontal visualization systems and a two-phase laminar flow simulation to investigate the tendency of invasive pattern transition by various parameters at the pore scale. We showed that increasing invasive viscosity or reducing interfacial tension in a homogeneous pore space significantly enhanced sweep efficiency, under constant capillary number. Additionally, in the fingering crossover pattern, the region near the inlet was prone to capillary fingering with multi-directional invasion, while the viscous fingering with unidirectional invasion was more susceptible occurred in the region near the outlet. Furthermore, increasing invasive viscosity or decreasing invasive velocity and interfacial tension promoted the extension of viscous fingering from the outlet to the inlet, presenting that the subsequent invasive fluid flows toward the outlet. In the case of invasive trunk along a unidirectional path, the invasive flow increased exponentially closer to the outlet, resulting in a significant decrease in the width of the invasive interface. Our work holds promising applications for optimizing invasive patterns in heterogeneous porous media.展开更多
The Fourier series of the 2π-periodic functions tg(x2)and 1sin(x)and some of their relatives (first of their integrals) are investigated and illustrated with respect to their convergence. These functions are Generali...The Fourier series of the 2π-periodic functions tg(x2)and 1sin(x)and some of their relatives (first of their integrals) are investigated and illustrated with respect to their convergence. These functions are Generalized functions and the convergence is weak convergence in the sense of the convergence of continuous linear functionals defining them. The figures show that the approximations of the Fourier series possess oscillations around the function which they represent in a broad band embedding them. This is some analogue to the Gibbs phenomenon. A modification of Fourier series by expansion in powers cosn(x)for the symmetric part of functions and sin(x)cosn−1(x)for the antisymmetric part (analogous to Taylor series) is discussed and illustrated by examples. The Fourier series and their convergence behavior are illustrated also for some 2π-periodic delta-function-like sequences connected with the Poisson theorem showing non-vanishing oscillations around the singularities similar to the Gibbs phenomenon in the neighborhood of discontinuities of functions. .展开更多
At the late stage of solidification with ultrasonic treatment （UST） in Al-Si alloys, a part of semisolid overflows and climbs along the probe. The interesting phenomenon and its influence on the solidification micro...At the late stage of solidification with ultrasonic treatment （UST） in Al-Si alloys, a part of semisolid overflows and climbs along the probe. The interesting phenomenon and its influence on the solidification microstructure were investigated in order to better study the mechanism of UST. It is considered that the overflowing phenomenon occurs due to the changes of vibration and flow in the remaining semisolid. Because the overflowed portion comes from the region with intense UST effect and vibrates with the probe during solidification, great modification of primary and euteetic Si （about 10 pm in length） and refinement of primary a（Al） （about 70 μm in size） are observed in this portion.展开更多
The time evolution of system in two photon Jaynes Cummings (J C) model without rotating waves approximation (RWA) is obtained by using the theory of ordinary differential equations. Based on the evolution, the mean ...The time evolution of system in two photon Jaynes Cummings (J C) model without rotating waves approximation (RWA) is obtained by using the theory of ordinary differential equations. Based on the evolution, the mean value of the atom inversion operator 〈 S 3(t)〉 is gi ven. The influence of the “counter rotating term” on the collapse and revival phenomenon is discussed from the comparison between the cases with RWA and without RWA. It shows that the influence of the virtual photon field makes the quantum fluctuations appear on the collapse and revival phenomenon.展开更多
A class of E1 Niйo atmospheric physics oscillation model is considered. The E1 Niйo atmospheric physics oscillation is an abnormal phenomenon involved in the tropical Pacific ocean-atmosphere interactions. The conce...A class of E1 Niйo atmospheric physics oscillation model is considered. The E1 Niйo atmospheric physics oscillation is an abnormal phenomenon involved in the tropical Pacific ocean-atmosphere interactions. The conceptual oscillator model should consider the variations of both the eastern and western Pacific anomaly patterns. An E1 Niйo atmospheric physics model is proposed using a method for the variational iteration theory. Using the variational iteration method, the approximate expansions of the solution of corresponding problem are constructed. That is, firstly, introducing a set of functional and accounting their variationals, the Lagrange multiplicators are counted, and then the variational iteration is defined, finally, the approximate solution is obtained. From approximate expansions of the solution, the zonal sea surface temperature anomaly in the equatorial eastern Pacific and the thermocline depth anomaly of the sea-air oscillation for E1 Niйo atmospheric physics model can be analyzed. E1 Niйo is a very complicated natural phenomenon. Hence basic models need to be reduced for the sea-air oscillator and are solved. The variational iteration is a simple and valid approximate method.展开更多
The Pearl River Mouth Basin （PRMB） covers an area of approximately 20× 104 km2.However,oil-gas fields detected in this area thus far are highly concentrated and controlled predominantly by second-order structur...The Pearl River Mouth Basin （PRMB） covers an area of approximately 20× 104 km2.However,oil-gas fields detected in this area thus far are highly concentrated and controlled predominantly by second-order structural belts,the seven largest of which aggregate proved oil reserves of 7.7× 108 m3,accounting for 86％ of the total discovered reserve in the basin.These second-order structures have one common phenomenon：oil is contained in all traps present in them.In other words,they are all belt-wide petroliferous reservoirs.Research has identified eight types of second-order structural belts under two categories in the eastern PRMB.Their petroliferous properties are subject to three typical constraints：petroliferous properties of subsags hosting these structural belts,locations of these belts in the petroleum system,and availability of traps prior to the hydrocarbon expulsion and migration.The formation and distribution of oil reservoirs in these belts are characterized by subsag-belt integration and ＂three-in-one＂.The former indicates that sags and the second-order structural belts within the supply range of the sags constitute the basic units of hydrocarbon accumulations and are therefore inseparable.The latter indicates that a belt-wide petroliferous second-order structural belt always contains three important elements：hydrocarbon richness,effective pathway and pre-existing traps.展开更多
Researchers reported that intravenously injected PEGylated colloidal drug carriers lose their long-circulating characteristic and accumulated extensively in liver when they are administrated twice in the same animal w...Researchers reported that intravenously injected PEGylated colloidal drug carriers lose their long-circulating characteristic and accumulated extensively in liver when they are administrated twice in the same animal with certain intervals. This phenomenon was referred to as the 'accelerated blood clearance(ABC) phenomenon'. Some former studies had found that complement-mediated phagocytosis, activated by antigen–antibody complex, was responsible for inducing the phenomenon. According to the theory, we have used cobra venom factor to deplete complement in vivo and to investigate the effect of complement inhibition on the ABC phenomenon. Rats were administered by injection of cobra venom factor solution to build up the model of complement exhaustion/inhibition, and the effect of the inhibition of complement on ABC phenomenon was carried out. It seemed that inhibition of complement didn’t affect the pharmacokinetic of the first infection. By contrast, in rats of which complement had been depleted, the second dose of PEGylated nanoemulsions showed enhanced circulation time compared with normal rats in a complement inhibition-independent manner, but the ABC phenomenon was not completely eliminated. It indicated that complement inhibition could certainly weaken the accelerated clearance;meanwhile, there were other factors causing the ABC effect.These findings provide novel insights into the attenuating of ABC phenomenon and lay foundation for further study of immune mechanism.展开更多
基金supported by the National Natural Science Foundation of China Joint Fund Project (Grant/Award Number: U20B6003)National Natural Science Foundation of China (Grant/Award Number: 52304054)。
文摘Understanding fingering, as a challenge to stable displacement during the immiscible flow, has become a crucial phenomenon for geological carbon sequestration, enhanced oil recovery, and groundwater protection. Typically governed by gravity, viscous and capillary forces, these factors lead invasive fluids to occupy pore space irregularly and incompletely. Previous studies have demonstrated capillary numbers,describing the viscous and capillary forces, to quantificationally induce evolution of invasion patterns.While the evolution mechanisms of invasive patterns have not been deeply elucidated under the constant capillary number and three variable parameters including velocity, viscosity, and interfacial tension.Our research employs two horizontal visualization systems and a two-phase laminar flow simulation to investigate the tendency of invasive pattern transition by various parameters at the pore scale. We showed that increasing invasive viscosity or reducing interfacial tension in a homogeneous pore space significantly enhanced sweep efficiency, under constant capillary number. Additionally, in the fingering crossover pattern, the region near the inlet was prone to capillary fingering with multi-directional invasion, while the viscous fingering with unidirectional invasion was more susceptible occurred in the region near the outlet. Furthermore, increasing invasive viscosity or decreasing invasive velocity and interfacial tension promoted the extension of viscous fingering from the outlet to the inlet, presenting that the subsequent invasive fluid flows toward the outlet. In the case of invasive trunk along a unidirectional path, the invasive flow increased exponentially closer to the outlet, resulting in a significant decrease in the width of the invasive interface. Our work holds promising applications for optimizing invasive patterns in heterogeneous porous media.
文摘The Fourier series of the 2π-periodic functions tg(x2)and 1sin(x)and some of their relatives (first of their integrals) are investigated and illustrated with respect to their convergence. These functions are Generalized functions and the convergence is weak convergence in the sense of the convergence of continuous linear functionals defining them. The figures show that the approximations of the Fourier series possess oscillations around the function which they represent in a broad band embedding them. This is some analogue to the Gibbs phenomenon. A modification of Fourier series by expansion in powers cosn(x)for the symmetric part of functions and sin(x)cosn−1(x)for the antisymmetric part (analogous to Taylor series) is discussed and illustrated by examples. The Fourier series and their convergence behavior are illustrated also for some 2π-periodic delta-function-like sequences connected with the Poisson theorem showing non-vanishing oscillations around the singularities similar to the Gibbs phenomenon in the neighborhood of discontinuities of functions. .
基金Project(50874022)supported by the National Natural Science Foundation of China
文摘At the late stage of solidification with ultrasonic treatment （UST） in Al-Si alloys, a part of semisolid overflows and climbs along the probe. The interesting phenomenon and its influence on the solidification microstructure were investigated in order to better study the mechanism of UST. It is considered that the overflowing phenomenon occurs due to the changes of vibration and flow in the remaining semisolid. Because the overflowed portion comes from the region with intense UST effect and vibrates with the probe during solidification, great modification of primary and euteetic Si （about 10 pm in length） and refinement of primary a（Al） （about 70 μm in size） are observed in this portion.
文摘The time evolution of system in two photon Jaynes Cummings (J C) model without rotating waves approximation (RWA) is obtained by using the theory of ordinary differential equations. Based on the evolution, the mean value of the atom inversion operator 〈 S 3(t)〉 is gi ven. The influence of the “counter rotating term” on the collapse and revival phenomenon is discussed from the comparison between the cases with RWA and without RWA. It shows that the influence of the virtual photon field makes the quantum fluctuations appear on the collapse and revival phenomenon.
文摘A class of E1 Niйo atmospheric physics oscillation model is considered. The E1 Niйo atmospheric physics oscillation is an abnormal phenomenon involved in the tropical Pacific ocean-atmosphere interactions. The conceptual oscillator model should consider the variations of both the eastern and western Pacific anomaly patterns. An E1 Niйo atmospheric physics model is proposed using a method for the variational iteration theory. Using the variational iteration method, the approximate expansions of the solution of corresponding problem are constructed. That is, firstly, introducing a set of functional and accounting their variationals, the Lagrange multiplicators are counted, and then the variational iteration is defined, finally, the approximate solution is obtained. From approximate expansions of the solution, the zonal sea surface temperature anomaly in the equatorial eastern Pacific and the thermocline depth anomaly of the sea-air oscillation for E1 Niйo atmospheric physics model can be analyzed. E1 Niйo is a very complicated natural phenomenon. Hence basic models need to be reduced for the sea-air oscillator and are solved. The variational iteration is a simple and valid approximate method.
文摘The Pearl River Mouth Basin （PRMB） covers an area of approximately 20× 104 km2.However,oil-gas fields detected in this area thus far are highly concentrated and controlled predominantly by second-order structural belts,the seven largest of which aggregate proved oil reserves of 7.7× 108 m3,accounting for 86％ of the total discovered reserve in the basin.These second-order structures have one common phenomenon：oil is contained in all traps present in them.In other words,they are all belt-wide petroliferous reservoirs.Research has identified eight types of second-order structural belts under two categories in the eastern PRMB.Their petroliferous properties are subject to three typical constraints：petroliferous properties of subsags hosting these structural belts,locations of these belts in the petroleum system,and availability of traps prior to the hydrocarbon expulsion and migration.The formation and distribution of oil reservoirs in these belts are characterized by subsag-belt integration and ＂three-in-one＂.The former indicates that sags and the second-order structural belts within the supply range of the sags constitute the basic units of hydrocarbon accumulations and are therefore inseparable.The latter indicates that a belt-wide petroliferous second-order structural belt always contains three important elements：hydrocarbon richness,effective pathway and pre-existing traps.
基金supported by the National Natural Science Foundation of China(Grant No.81373334)
文摘Researchers reported that intravenously injected PEGylated colloidal drug carriers lose their long-circulating characteristic and accumulated extensively in liver when they are administrated twice in the same animal with certain intervals. This phenomenon was referred to as the 'accelerated blood clearance(ABC) phenomenon'. Some former studies had found that complement-mediated phagocytosis, activated by antigen–antibody complex, was responsible for inducing the phenomenon. According to the theory, we have used cobra venom factor to deplete complement in vivo and to investigate the effect of complement inhibition on the ABC phenomenon. Rats were administered by injection of cobra venom factor solution to build up the model of complement exhaustion/inhibition, and the effect of the inhibition of complement on ABC phenomenon was carried out. It seemed that inhibition of complement didn’t affect the pharmacokinetic of the first infection. By contrast, in rats of which complement had been depleted, the second dose of PEGylated nanoemulsions showed enhanced circulation time compared with normal rats in a complement inhibition-independent manner, but the ABC phenomenon was not completely eliminated. It indicated that complement inhibition could certainly weaken the accelerated clearance;meanwhile, there were other factors causing the ABC effect.These findings provide novel insights into the attenuating of ABC phenomenon and lay foundation for further study of immune mechanism.
