CO2 capture by hydrate formation is a novel gas separation technology, by which CO2 is selectively engaged in the cages of hydrate and is separated with other gases, based on the differences of phase equilibrium for C...CO2 capture by hydrate formation is a novel gas separation technology, by which CO2 is selectively engaged in the cages of hydrate and is separated with other gases, based on the differences of phase equilibrium for CO2 and other gases. However. rigorous temperature and pressure, high energy cost and industrialized hydration separator dragged the development of the hydrate based CO2 capture. In this paper, the key problems in CO2 capture from the different sources such as shifted synthesis gas, flue gas and sour natural gas or biogas were analyzed. For shifted synthesis gas and flue gas, its high energy consumption is the barrier, and for the sour natural gas or biogas （CO2/CH4 system）, the bottleneck is how to enhance the selectivity of CO2 hydration. For these gases, scale-up is the main difficulty. Also, this paper explored the possibility of separating different gases by selective hydrate formation and reviewed the progress of CO2 separation from shifted synthesis gas, flue gas and sour natural gas or biogas.展开更多
This paper is a continuation of our previous work [Front. Math. China, 2016, 11（6）： 1379-1418] where an efficient algorithm for computing the maximal eigenpalr was introduced first for tridiagonal matrices and then...This paper is a continuation of our previous work [Front. Math. China, 2016, 11（6）： 1379-1418] where an efficient algorithm for computing the maximal eigenpalr was introduced first for tridiagonal matrices and then extended to the irreducible matrices with nonnegative off-diagonal elements. This paper introduces mainly two global algorithms for computing the maximal eigenpair in a rather general setup, including even a class of real （with some negative off-diagonal elements） or complex matrices.展开更多
The decomposition and identification of signals are crucial for flow vector acquisition in a multi-dimensional measurement. Here, we proposed a two-dimensional(2D) flow vector measurement system based on all-fiber las...The decomposition and identification of signals are crucial for flow vector acquisition in a multi-dimensional measurement. Here, we proposed a two-dimensional(2D) flow vector measurement system based on all-fiber laser feedback frequency-shifted multiplexing technology. The reliable performance of the system is characterized by experimental verification and numerical simulation. An orthogonal dual-beam structure is employed to eliminate the impact of an unknown incident angle in the practical application. Meanwhile, the vector velocity signals in 2D can be decomposed into one-dimensional(1D) scalar signals by adopting the frequency-shifted multiplexing,which makes it easy to obtain the vector information and velocity distribution of fluid motion through the self-mixing interference frequency spectrum.展开更多
Aiming at different sensing characteristics on waveform and amplitude of aπ-phase-shifted fiber Bragg grating under axially and vertically incident ultrasonic wave in water, a fiber Bragg grating ultrasonic sensing m...Aiming at different sensing characteristics on waveform and amplitude of aπ-phase-shifted fiber Bragg grating under axially and vertically incident ultrasonic wave in water, a fiber Bragg grating ultrasonic sensing model is established based on transfer matrix method. Inhomogeneous strain fields along grating under axially and vertically incident ultrasonic wave are calculated, which helps analyze sensing characteristics of π-phase-shifted fiber Bragg grating under above two situations by using further wavelength shift results. Experiments are then performed to verify analytical results. Results show that the sensing characteristics of π-phase-shifted fiber Bragg grating are obviously affected by different inhomogeneous strain field distributions under two incident angles. Both sensing waveform and amplitude under vertically incident ultrasonic wave perform better than axially, and π phase shift plays a significant effect on sensing characteristics. With the increase of the distance between incident position and phase shift point, the response under vertically incident ultrasonic significantly declines. The research provides guidance for analyzing ultrasonic sensing mechanism of π-phase-shifted fiber Bragg grating.展开更多
This paper proposes a new set of 3D rotation scaling and translation invariants of 3D radially shifted Legendre moments. We aim to develop two kinds of transformed shifted Legendre moments： a 3D substituted radial sh...This paper proposes a new set of 3D rotation scaling and translation invariants of 3D radially shifted Legendre moments. We aim to develop two kinds of transformed shifted Legendre moments： a 3D substituted radial shifted Legendre moments （3DSRSLMs） and a 3D weighted radial one （3DWRSLMs）. Both are centered on two types of polynomials. In the first case, a new 3D ra- dial complex moment is proposed. In the second case, new 3D substituted/weighted radial shifted Legendremoments （3DSRSLMs/3DWRSLMs） are introduced using a spherical representation of volumetric image. 3D invariants as derived from the sug- gested 3D radial shifted Legendre moments will appear in the third case. To confirm the proposed approach, we have resolved three is- sues. To confirm the proposed approach, we have resolved three issues： rotation, scaling and translation invariants. The result of experi- ments shows that the 3DSRSLMs and 3DWRSLMs have done better than the 3D radial complex moments with and without noise. Sim- ultaneously, the reconstruction converges rapidly to the original image using 3D radial 3DSRSLMs and 3DWRSLMs, and the test of 3D images are clearly recognized from a set of images that are available in Princeton shape benchmark （PSB） database for 3D image.展开更多
The transmission characteristics of the optical label switching system based on the FSK/ASK orthogonal modulation format is investigated. The factors that affect the transmission performance, such as the FSK tone spac...The transmission characteristics of the optical label switching system based on the FSK/ASK orthogonal modulation format is investigated. The factors that affect the transmission performance, such as the FSK tone space, dispersion compensation and coupler split ratio, are studied by numerical simulation. The proposed scheme is also experimentally demonstrated with a transmission of 155 Mbit/s FSK label combined with 10 Gbit/s ASK payload.展开更多
A novel current-source active power filter (APF) based on multi-modular converter with carrier phase-shifted SPWM (CPS-SPWM) technique is proposed. With this technique, the effect of equivalent high switching frequenc...A novel current-source active power filter (APF) based on multi-modular converter with carrier phase-shifted SPWM (CPS-SPWM) technique is proposed. With this technique, the effect of equivalent high switching frequency con-verter is obtained with low switching frequency converter. It is very promising in current-source APF that adopt super-conducting magnetic energy storage component.展开更多
Frequency engineering of whispering-gallery resonances is essential in microcavity nonlinear optics.The key is to control the frequencies of the cavity modes involved in the underlying nonlinear optical process to sat...Frequency engineering of whispering-gallery resonances is essential in microcavity nonlinear optics.The key is to control the frequencies of the cavity modes involved in the underlying nonlinear optical process to satisfy its energy conservation criterion.Compared to the conventional method that tailors dispersion by cross-sectional geometry,thereby impacting all cavity mode frequencies,grating-assisted microring cavities,often termed as photonic crystal microrings,provide more enabling capabilities through mode-selective frequency control.For example,a simple single period grating added to a microring has been used for single frequency engineering in Kerr optical parametric oscillation(OPO)and frequency combs.Recently,this approach has been extended to multifrequency engineering by using multi-period grating functions,but at the cost of increasingly complex grating profiles that require challenging fabrication.Here,we demonstrate a simple approach,which we term as shifted grating multiple mode splitting(SGMMS),where spatial displacement of a single period grating imprinted on the inner boundary of the microring creates a rotational asymmetry that frequency splits multiple adjacent cavity modes.This approach is easy to implement and presents no additional fabrication challenges compared to an unshifted grating,and yet is very powerful in providing multi-frequency engineering functionality for nonlinear optics.We showcase an example where SGMMS enables OPO across a wide range of pump wavelengths in a normal-dispersion device that otherwise would not support OPO.展开更多
Code delay and Doppler shifted frequency could not be captured by using the conventional GPS receiver in strong interference environments because the received GPS signals which traveled a long distance are very weak. ...Code delay and Doppler shifted frequency could not be captured by using the conventional GPS receiver in strong interference environments because the received GPS signals which traveled a long distance are very weak. An anti-jamming GPS receiver is proposed. The interferences in the received signals are can- celled by using subspace projecting technique, and the resulting interference-free signals are processed by a weight vector which maximizes the signal-to-noise ratio. Simulation is conducted, and the results show that the method is valid.展开更多
In this paper we will see the model of Universe according to Dynamic Universe Model of Cosmology by visualizing various processes that are happening in the Universe as per experimental evidences. For simplifying the m...In this paper we will see the model of Universe according to Dynamic Universe Model of Cosmology by visualizing various processes that are happening in the Universe as per experimental evidences. For simplifying the matter here, we will see in part 1: about the Galaxy life cycle, where the birth and death of Galaxies discussed. Probably Universe gives guidance for the movement of Galaxies. We call this Part 1: Thinking and Reproducing Universe or Mindless Universe? (Galaxy life cycle). We see every day Sun, Stars, Galaxies etc., dissipating enormous energy in the form of radiation by the way of fusion of Hydrogen to helium. So after sometime all the Hydrogen is spent and Universe will die, is it not? … Dynamic Universe Model says that the energy in the form of electromagnetic radiation passing grazingly near any gravitating mass changes in frequency and finally will convert into neutrinos (mass). Hence Dynamic Universe Model proposes another process where energy will be converted back into matter and the cycle energy to mass to energy continues, sustaining the Universe to maintain this present status for ever in this form something like a Steady state model without any expansion. This we will see in Part 2: Energy - Mass - Energy Cycle. After converting energy into mass “how various elements are formed and where they are formed?” will be next logical question. Dynamic Universe Model says that these various particles change into higher massive particles or may get bombarded into stars or planets and various elements are formed. Here we bifurcate the formation of elements into 6 processes. They are for Elementary particles and elements generated in frequency changing process, By Cosmic rays, By Small stars, By Large Stars, By Super Novae and Manmade elements By Neutron Stars. This we will discuss in Part 3: Nucleosynthesis.展开更多
An additional potential energy distribution function is introduced on the basis of previous D3Q25 model,and the equilibrium distribution function of D3Q25 is obtained by spherical function.A novel three-dimensional(3D...An additional potential energy distribution function is introduced on the basis of previous D3Q25 model,and the equilibrium distribution function of D3Q25 is obtained by spherical function.A novel three-dimensional(3D)shifted lattice model is proposed,therefore a shifted lattice model is introduced into D3Q25.Under the finite volume scheme,several typical compressible calculation examples are used to verify whether the numerical stability of the D3Q25 model can be improved by adding the shifted lattice model.The simulation results show that the numerical stability is indeed improved after adding the shifted lattice model.展开更多
In this manuscript,an algorithm for the computation of numerical solutions to some variable order fractional differential equations(FDEs)subject to the boundary and initial conditions is developed.We use shifted Legen...In this manuscript,an algorithm for the computation of numerical solutions to some variable order fractional differential equations(FDEs)subject to the boundary and initial conditions is developed.We use shifted Legendre polynomials for the required numerical algorithm to develop some operational matrices.Further,operational matrices are constructed using variable order differentiation and integration.We are finding the operationalmatrices of variable order differentiation and integration by omitting the discretization of data.With the help of aforesaid matrices,considered FDEs are converted to algebraic equations of Sylvester type.Finally,the algebraic equations we get are solved with the help of mathematical software like Matlab or Mathematica to compute numerical solutions.Some examples are given to check the proposed method’s accuracy and graphical representations.Exact and numerical solutions are also compared in the paper for some examples.The efficiency of the method can be enhanced further by increasing the scale level.展开更多
A simple criterion is studied for the first time for identifying the discrete energy dissipation of the Crank-Nicolson scheme for Maxwell’s equations in a Cole-Cole dispersive medium.Several numerical formulas that a...A simple criterion is studied for the first time for identifying the discrete energy dissipation of the Crank-Nicolson scheme for Maxwell’s equations in a Cole-Cole dispersive medium.Several numerical formulas that approximate the time fractional derivatives are investigated based on this criterion,including the L1 formula,the fractional BDF-2,and the shifted fractional trapezoidal rule(SFTR).Detailed error analysis is provided within the framework of time domain mixed finite element methods for smooth solutions.The convergence results and discrete energy dissipation law are confirmed by numerical tests.For nonsmooth solutions,the method SFTR can still maintain the optimal convergence order at a positive time on uniform meshes.Authors believe this is the first appearance that a second-order time-stepping method can restore the optimal convergence rate for Maxwell’s equations in a Cole-Cole dispersive medium regardless of the initial singularity of the solution.展开更多
This paper is a continuation of our previous paper[Front.Math.China,2017,12(5):10231043]where global algorithms for computing the maximal cigcnpair were introduced in a rather general setup.The efficiency of the globa...This paper is a continuation of our previous paper[Front.Math.China,2017,12(5):10231043]where global algorithms for computing the maximal cigcnpair were introduced in a rather general setup.The efficiency of the global algorithms is improved in this paper in terms of a good use of power iteration and two quasi-symmetric techniques.Finally,the new algorithms are applied to Hua’s economic optimization model.展开更多
“Do you like the seh-parcha(羊皮纸)?”I said,holding up the kite by the ends of the cross bars.His eyes shifted from the sky to me,to the kite,then back.A few rivulets of rain trickled from his hair,down his face.
A novel optical return zero differential quadrature phase shifted keying/inverse return zero amplitude shifted keying （RZ-DQPSFUIRZ-ASK） orthogonal modulation format scheme for all-optical label swapping is analyzed...A novel optical return zero differential quadrature phase shifted keying/inverse return zero amplitude shifted keying （RZ-DQPSFUIRZ-ASK） orthogonal modulation format scheme for all-optical label swapping is analyzed theoretically and experimentally. The transmission characteristics of RZ-DQPSK/IRZ-ASK modulation format transmission system are demonstrated. Results show that high extinction ratio is obtained for IRZ-ASK label signal while at the same time the all-optical label swapping, differential quadrature phase shifted keying （DQPSK） payload signal is hardly affected. It requires only 0.9 dB higher power penalty compared to 21.4 Gbit/s RZ-DQPSK modulation format and less than 2 dB transmission penalty after 60 km. The proposed scheme is a practical solution for meeting the data rate and cost-efficiency of the optical links simultaneously in future all-optical label swapping.展开更多
Quantitative precipitation forecasts(QPFs)provided by three operational global ensemble prediction systems(EPSs)from the THORPEX(The Observing System Research and Predictability Experiment)Interactive Grand Global Ens...Quantitative precipitation forecasts(QPFs)provided by three operational global ensemble prediction systems(EPSs)from the THORPEX(The Observing System Research and Predictability Experiment)Interactive Grand Global Ensemble(TIGGE)archive were evaluated over the Qu River basin,China during the plum rain and typhoon seasons of 2009–13.Two post-processing methods,the ensemble model output statistics based on censored shifted gamma distribution(CSGD-EMOS)and quantile mapping(QM),were used to reduce bias and to improve the QPFs.The results were evaluated by using three incremental precipitation thresholds and multiple verification metrics.It is demonstrated that QPFs from NCEP and ECMWF presented similarly skillful forecasts,although the ECMWF QPFs performed more satisfactorily in the typhoon season and the NCEP QPFs were better in the plum rain season.Most of the verification metrics showed evident seasonal discriminations,with more satisfactory behavior in the plum rain season.Lighter precipitation tended to be overestimated,but heavier precipitation was always underestimated.The post-processed QPFs showed a significant improvement from the raw forecasts and the effects of post-processing varied with the lead time,precipitation threshold,and EPS.Precipitation was better corrected at longer lead times and higher thresholds.CSGD-EMOS was more effective for probabilistic metrics and the root-mean-square error.QM had a greater effect on removing bias according to bias and categorical metrics,but was unable to warrant reliabilities.In general,raw forecasts can provide acceptable QPFs eight days in advance.After post-processing,the useful forecasts can be significantly extended beyond 10 days,showing promising prospects for flood forecasting.展开更多
A terahertz metamaterial sensor adopting the metamaterial-based electromagnetically induced transparency（EIT） effect is presented for determining the 1,4-dioxane concentration in its aqueous solution. The metamateri...A terahertz metamaterial sensor adopting the metamaterial-based electromagnetically induced transparency（EIT） effect is presented for determining the 1,4-dioxane concentration in its aqueous solution. The metamaterial sensor, which consists of an EIT element unit with a cut-wire metallic resonator and two split-ring metallic resonators fabricated on a 490-μm thick silicon substrate, operates in a transmission geometry. The EIT peak was red-shifted and decreased with the increase of the water volume. A maximum redshift about 54 GHz of the EIT peak was detected between the 1,4-dioxane and water. The presented linear behavior and high sensitivity of the EIT peak depending on the water concentration pave a novel avenue for sensor applications.展开更多
基金the National Natural Science Foundation of China(Grant No.51176051 and 51106054)the National Basic Research Program of China(973 Program,No.2009CB219504-03)
文摘CO2 capture by hydrate formation is a novel gas separation technology, by which CO2 is selectively engaged in the cages of hydrate and is separated with other gases, based on the differences of phase equilibrium for CO2 and other gases. However. rigorous temperature and pressure, high energy cost and industrialized hydration separator dragged the development of the hydrate based CO2 capture. In this paper, the key problems in CO2 capture from the different sources such as shifted synthesis gas, flue gas and sour natural gas or biogas were analyzed. For shifted synthesis gas and flue gas, its high energy consumption is the barrier, and for the sour natural gas or biogas （CO2/CH4 system）, the bottleneck is how to enhance the selectivity of CO2 hydration. For these gases, scale-up is the main difficulty. Also, this paper explored the possibility of separating different gases by selective hydrate formation and reviewed the progress of CO2 separation from shifted synthesis gas, flue gas and sour natural gas or biogas.
文摘This paper is a continuation of our previous work [Front. Math. China, 2016, 11（6）： 1379-1418] where an efficient algorithm for computing the maximal eigenpalr was introduced first for tridiagonal matrices and then extended to the irreducible matrices with nonnegative off-diagonal elements. This paper introduces mainly two global algorithms for computing the maximal eigenpair in a rather general setup, including even a class of real （with some negative off-diagonal elements） or complex matrices.
基金National Natural Science Foundation of China(62275001, 62105001, 62205001)。
文摘The decomposition and identification of signals are crucial for flow vector acquisition in a multi-dimensional measurement. Here, we proposed a two-dimensional(2D) flow vector measurement system based on all-fiber laser feedback frequency-shifted multiplexing technology. The reliable performance of the system is characterized by experimental verification and numerical simulation. An orthogonal dual-beam structure is employed to eliminate the impact of an unknown incident angle in the practical application. Meanwhile, the vector velocity signals in 2D can be decomposed into one-dimensional(1D) scalar signals by adopting the frequency-shifted multiplexing,which makes it easy to obtain the vector information and velocity distribution of fluid motion through the self-mixing interference frequency spectrum.
基金supported by the National Natural Science Foundation of China (11674351)。
文摘Aiming at different sensing characteristics on waveform and amplitude of aπ-phase-shifted fiber Bragg grating under axially and vertically incident ultrasonic wave in water, a fiber Bragg grating ultrasonic sensing model is established based on transfer matrix method. Inhomogeneous strain fields along grating under axially and vertically incident ultrasonic wave are calculated, which helps analyze sensing characteristics of π-phase-shifted fiber Bragg grating under above two situations by using further wavelength shift results. Experiments are then performed to verify analytical results. Results show that the sensing characteristics of π-phase-shifted fiber Bragg grating are obviously affected by different inhomogeneous strain field distributions under two incident angles. Both sensing waveform and amplitude under vertically incident ultrasonic wave perform better than axially, and π phase shift plays a significant effect on sensing characteristics. With the increase of the distance between incident position and phase shift point, the response under vertically incident ultrasonic significantly declines. The research provides guidance for analyzing ultrasonic sensing mechanism of π-phase-shifted fiber Bragg grating.
文摘This paper proposes a new set of 3D rotation scaling and translation invariants of 3D radially shifted Legendre moments. We aim to develop two kinds of transformed shifted Legendre moments： a 3D substituted radial shifted Legendre moments （3DSRSLMs） and a 3D weighted radial one （3DWRSLMs）. Both are centered on two types of polynomials. In the first case, a new 3D ra- dial complex moment is proposed. In the second case, new 3D substituted/weighted radial shifted Legendremoments （3DSRSLMs/3DWRSLMs） are introduced using a spherical representation of volumetric image. 3D invariants as derived from the sug- gested 3D radial shifted Legendre moments will appear in the third case. To confirm the proposed approach, we have resolved three is- sues. To confirm the proposed approach, we have resolved three issues： rotation, scaling and translation invariants. The result of experi- ments shows that the 3DSRSLMs and 3DWRSLMs have done better than the 3D radial complex moments with and without noise. Sim- ultaneously, the reconstruction converges rapidly to the original image using 3D radial 3DSRSLMs and 3DWRSLMs, and the test of 3D images are clearly recognized from a set of images that are available in Princeton shape benchmark （PSB） database for 3D image.
基金supported by the National Natural Science Foundation of China(Grant No 60677004)the National High Technology Research and Development Program of China(Grant No 2007AA01Z260)+4 种基金The project is also supported by the Key Project of Chinese Ministry of Education(Grant No 107011)the Key Laboratory of Broadband Optical Fiber Transmission and Communication Networks(UESTC)(Ministry of Education of China)Teaching and Scientific Research Foundation for the Returned Overseas Chinese Scholars(State Education Ministry of China)the Corporative Building Project of Beijing Educational Committee(Grant No XK100130737)the Program for New Century Excellent Talents in University of China(Grant No NECT-07-0111)
文摘The transmission characteristics of the optical label switching system based on the FSK/ASK orthogonal modulation format is investigated. The factors that affect the transmission performance, such as the FSK tone space, dispersion compensation and coupler split ratio, are studied by numerical simulation. The proposed scheme is also experimentally demonstrated with a transmission of 155 Mbit/s FSK label combined with 10 Gbit/s ASK payload.
文摘A novel current-source active power filter (APF) based on multi-modular converter with carrier phase-shifted SPWM (CPS-SPWM) technique is proposed. With this technique, the effect of equivalent high switching frequency con-verter is obtained with low switching frequency converter. It is very promising in current-source APF that adopt super-conducting magnetic energy storage component.
基金Maryland Innovation InitiativeNational Institute of Standards and Technology(NIST-on-a-chip)Defense Advanced Research Projects Agency(LUMOS)。
文摘Frequency engineering of whispering-gallery resonances is essential in microcavity nonlinear optics.The key is to control the frequencies of the cavity modes involved in the underlying nonlinear optical process to satisfy its energy conservation criterion.Compared to the conventional method that tailors dispersion by cross-sectional geometry,thereby impacting all cavity mode frequencies,grating-assisted microring cavities,often termed as photonic crystal microrings,provide more enabling capabilities through mode-selective frequency control.For example,a simple single period grating added to a microring has been used for single frequency engineering in Kerr optical parametric oscillation(OPO)and frequency combs.Recently,this approach has been extended to multifrequency engineering by using multi-period grating functions,but at the cost of increasingly complex grating profiles that require challenging fabrication.Here,we demonstrate a simple approach,which we term as shifted grating multiple mode splitting(SGMMS),where spatial displacement of a single period grating imprinted on the inner boundary of the microring creates a rotational asymmetry that frequency splits multiple adjacent cavity modes.This approach is easy to implement and presents no additional fabrication challenges compared to an unshifted grating,and yet is very powerful in providing multi-frequency engineering functionality for nonlinear optics.We showcase an example where SGMMS enables OPO across a wide range of pump wavelengths in a normal-dispersion device that otherwise would not support OPO.
基金supported by the National Natural Science Foundation of China (60472052 10577007)+1 种基金the Program for New Century Excellent Talents in University (2004)the National Key Lab Foundation of National Anti-Interference Communication Technology Laboratory
文摘Code delay and Doppler shifted frequency could not be captured by using the conventional GPS receiver in strong interference environments because the received GPS signals which traveled a long distance are very weak. An anti-jamming GPS receiver is proposed. The interferences in the received signals are can- celled by using subspace projecting technique, and the resulting interference-free signals are processed by a weight vector which maximizes the signal-to-noise ratio. Simulation is conducted, and the results show that the method is valid.
文摘In this paper we will see the model of Universe according to Dynamic Universe Model of Cosmology by visualizing various processes that are happening in the Universe as per experimental evidences. For simplifying the matter here, we will see in part 1: about the Galaxy life cycle, where the birth and death of Galaxies discussed. Probably Universe gives guidance for the movement of Galaxies. We call this Part 1: Thinking and Reproducing Universe or Mindless Universe? (Galaxy life cycle). We see every day Sun, Stars, Galaxies etc., dissipating enormous energy in the form of radiation by the way of fusion of Hydrogen to helium. So after sometime all the Hydrogen is spent and Universe will die, is it not? … Dynamic Universe Model says that the energy in the form of electromagnetic radiation passing grazingly near any gravitating mass changes in frequency and finally will convert into neutrinos (mass). Hence Dynamic Universe Model proposes another process where energy will be converted back into matter and the cycle energy to mass to energy continues, sustaining the Universe to maintain this present status for ever in this form something like a Steady state model without any expansion. This we will see in Part 2: Energy - Mass - Energy Cycle. After converting energy into mass “how various elements are formed and where they are formed?” will be next logical question. Dynamic Universe Model says that these various particles change into higher massive particles or may get bombarded into stars or planets and various elements are formed. Here we bifurcate the formation of elements into 6 processes. They are for Elementary particles and elements generated in frequency changing process, By Cosmic rays, By Small stars, By Large Stars, By Super Novae and Manmade elements By Neutron Stars. This we will discuss in Part 3: Nucleosynthesis.
基金the Youth Program of the National Natural Science Foundation of China(Grant Nos.11972272,12072246,and 12202331)the National Key Project,China(Grant No.GJXM92579)the Natural Science Basic Research Program of Shaanxi Province,China(Program No.2022JQ-028)。
文摘An additional potential energy distribution function is introduced on the basis of previous D3Q25 model,and the equilibrium distribution function of D3Q25 is obtained by spherical function.A novel three-dimensional(3D)shifted lattice model is proposed,therefore a shifted lattice model is introduced into D3Q25.Under the finite volume scheme,several typical compressible calculation examples are used to verify whether the numerical stability of the D3Q25 model can be improved by adding the shifted lattice model.The simulation results show that the numerical stability is indeed improved after adding the shifted lattice model.
基金Supporting Project No.(PNURSP2022R 14),Princess Nourah bint A bdurahman University,Riyadh,Saudi Arabia.
文摘In this manuscript,an algorithm for the computation of numerical solutions to some variable order fractional differential equations(FDEs)subject to the boundary and initial conditions is developed.We use shifted Legendre polynomials for the required numerical algorithm to develop some operational matrices.Further,operational matrices are constructed using variable order differentiation and integration.We are finding the operationalmatrices of variable order differentiation and integration by omitting the discretization of data.With the help of aforesaid matrices,considered FDEs are converted to algebraic equations of Sylvester type.Finally,the algebraic equations we get are solved with the help of mathematical software like Matlab or Mathematica to compute numerical solutions.Some examples are given to check the proposed method’s accuracy and graphical representations.Exact and numerical solutions are also compared in the paper for some examples.The efficiency of the method can be enhanced further by increasing the scale level.
基金supported in part by the Grant No.NSFC 12201322supported in part by Grant No.NSFC 12061053+1 种基金supported in part by the Grant Nos.NSFC 12161063 and the NSF of Inner Mongolia 2021MS01018supported in part by Grant Nos.NSFC 11871092 and NSAF U1930402.
文摘A simple criterion is studied for the first time for identifying the discrete energy dissipation of the Crank-Nicolson scheme for Maxwell’s equations in a Cole-Cole dispersive medium.Several numerical formulas that approximate the time fractional derivatives are investigated based on this criterion,including the L1 formula,the fractional BDF-2,and the shifted fractional trapezoidal rule(SFTR).Detailed error analysis is provided within the framework of time domain mixed finite element methods for smooth solutions.The convergence results and discrete energy dissipation law are confirmed by numerical tests.For nonsmooth solutions,the method SFTR can still maintain the optimal convergence order at a positive time on uniform meshes.Authors believe this is the first appearance that a second-order time-stepping method can restore the optimal convergence rate for Maxwell’s equations in a Cole-Cole dispersive medium regardless of the initial singularity of the solution.
基金This work was supported in part by the National Natural Science Foundation of China(Grant No.11771046)the Project from the Ministry of Education in China,and the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘This paper is a continuation of our previous paper[Front.Math.China,2017,12(5):10231043]where global algorithms for computing the maximal cigcnpair were introduced in a rather general setup.The efficiency of the global algorithms is improved in this paper in terms of a good use of power iteration and two quasi-symmetric techniques.Finally,the new algorithms are applied to Hua’s economic optimization model.
文摘“Do you like the seh-parcha(羊皮纸)?”I said,holding up the kite by the ends of the cross bars.His eyes shifted from the sky to me,to the kite,then back.A few rivulets of rain trickled from his hair,down his face.
基金supported by the National Basic Research Program of China (2003CB314901)the Hi-Tech Research and Development Project of China (2006AA03Z416,2007AA03Z418)+2 种基金the National Natural Science Foundation of China (60576018)the 111 Project (B07005)the Program for Changjiang Scholars and Innovative Research Team in University,MOE
文摘A novel optical return zero differential quadrature phase shifted keying/inverse return zero amplitude shifted keying （RZ-DQPSFUIRZ-ASK） orthogonal modulation format scheme for all-optical label swapping is analyzed theoretically and experimentally. The transmission characteristics of RZ-DQPSK/IRZ-ASK modulation format transmission system are demonstrated. Results show that high extinction ratio is obtained for IRZ-ASK label signal while at the same time the all-optical label swapping, differential quadrature phase shifted keying （DQPSK） payload signal is hardly affected. It requires only 0.9 dB higher power penalty compared to 21.4 Gbit/s RZ-DQPSK modulation format and less than 2 dB transmission penalty after 60 km. The proposed scheme is a practical solution for meeting the data rate and cost-efficiency of the optical links simultaneously in future all-optical label swapping.
基金Supported by the National Key Research and Development Program(2016YFE0122100)National Natural Science Foundation of China(91547106)
文摘Quantitative precipitation forecasts(QPFs)provided by three operational global ensemble prediction systems(EPSs)from the THORPEX(The Observing System Research and Predictability Experiment)Interactive Grand Global Ensemble(TIGGE)archive were evaluated over the Qu River basin,China during the plum rain and typhoon seasons of 2009–13.Two post-processing methods,the ensemble model output statistics based on censored shifted gamma distribution(CSGD-EMOS)and quantile mapping(QM),were used to reduce bias and to improve the QPFs.The results were evaluated by using three incremental precipitation thresholds and multiple verification metrics.It is demonstrated that QPFs from NCEP and ECMWF presented similarly skillful forecasts,although the ECMWF QPFs performed more satisfactorily in the typhoon season and the NCEP QPFs were better in the plum rain season.Most of the verification metrics showed evident seasonal discriminations,with more satisfactory behavior in the plum rain season.Lighter precipitation tended to be overestimated,but heavier precipitation was always underestimated.The post-processed QPFs showed a significant improvement from the raw forecasts and the effects of post-processing varied with the lead time,precipitation threshold,and EPS.Precipitation was better corrected at longer lead times and higher thresholds.CSGD-EMOS was more effective for probabilistic metrics and the root-mean-square error.QM had a greater effect on removing bias according to bias and categorical metrics,but was unable to warrant reliabilities.In general,raw forecasts can provide acceptable QPFs eight days in advance.After post-processing,the useful forecasts can be significantly extended beyond 10 days,showing promising prospects for flood forecasting.
基金supported by the National Basic Research Program of China under Grant No.2014CB339800
文摘A terahertz metamaterial sensor adopting the metamaterial-based electromagnetically induced transparency（EIT） effect is presented for determining the 1,4-dioxane concentration in its aqueous solution. The metamaterial sensor, which consists of an EIT element unit with a cut-wire metallic resonator and two split-ring metallic resonators fabricated on a 490-μm thick silicon substrate, operates in a transmission geometry. The EIT peak was red-shifted and decreased with the increase of the water volume. A maximum redshift about 54 GHz of the EIT peak was detected between the 1,4-dioxane and water. The presented linear behavior and high sensitivity of the EIT peak depending on the water concentration pave a novel avenue for sensor applications.
