The singularly perturbed elliptic equation boundary value problem with turning point is considered. Using the method of multiple scales and the comparison theorem, the asymptotic behavior of solution for the boundary ...The singularly perturbed elliptic equation boundary value problem with turning point is considered. Using the method of multiple scales and the comparison theorem, the asymptotic behavior of solution for the boundary value problem is studied.展开更多
Departing from an analytical phase transformation model, a new analytical approach to deduce transformed fraction for non-isothermal phase transformation was developed. In the new approach, the effect of the initial t...Departing from an analytical phase transformation model, a new analytical approach to deduce transformed fraction for non-isothermal phase transformation was developed. In the new approach, the effect of the initial transformation temperature and the accurate "temperature integral" approximations are incorporated to obtain an extended analytical model. Numerical approach demonstrated that the extended analytical model prediction for transformed fraction and transformation rate is in good agreement with the exact numerical calculation. The new model can describe more precisely the kinetic behavior than the original analytical model, especially for transformation with relatively high initial transformation temperature. The kinetic parameters obtained from the new model are more accurate and reasonable than those from the original analytical model.展开更多
A capacitor self-calibration circuit used in a successive approximation analog-to-digital converter (SA-ADC) is presented. This capacitor self-calibration circuit can calibrate erroneous data and work with the ADC b...A capacitor self-calibration circuit used in a successive approximation analog-to-digital converter (SA-ADC) is presented. This capacitor self-calibration circuit can calibrate erroneous data and work with the ADC by adding an additional clock period. This circuit is used in a 10 bit 32 Msample/s time-interleaved SA- ADC. The chip is implemented with Chart 0. 25 μm 2. 5 V process and totally occupies an area of 1.4 mm× 1.3 mm. After calibration, the simulated signal-to-noise ratio (SNR) is 59. 586 1 dB and the spurious-free dynamic range (SFDR) is 70. 246 dB at 32 MHz. The measured signal-to-noise and distortion ratio (SINAD) is 44. 82 dB and the SFDR is 63. 760 4 dB when the ADC samples a 5.8 MHz sinusoid wave.展开更多
The atomic inversion dynamics in the mode-mode competing system is studied bymeans of fully quantum theory. A general solution to the Schroedinger equation of this system isobtained. The influence of the relative comp...The atomic inversion dynamics in the mode-mode competing system is studied bymeans of fully quantum theory. A general solution to the Schroedinger equation of this system isobtained. The influence of the relative competing strength between the atom and the two-mode Geld onthe atomic inversion is disccussed. We show that the presence of the mode-mode competition canresult in periodical collapses-revivals of the atomic inversion.展开更多
The corresponding solution for a class of disturbed KdV equation is considered using the analytic method. From the generalized variational iteration theory, the problem of solving soliton for the corresponding equatio...The corresponding solution for a class of disturbed KdV equation is considered using the analytic method. From the generalized variational iteration theory, the problem of solving soliton for the corresponding equation translates into the problem of variational iteration. And then the approximate solution of the soliton for the equation is obtained.展开更多
Comparator offset cancellation and capacitor self-calibration techniques used in a successive approximation analog-to-digital converter (SA-ADC) are described. The calibration circuit works in parallel with the SAAD...Comparator offset cancellation and capacitor self-calibration techniques used in a successive approximation analog-to-digital converter (SA-ADC) are described. The calibration circuit works in parallel with the SAADC by adding additional calibration clock cycles to pursue high accuracy and low power consumption, and the calibrated resolution can be up to 14bit. This circuit is used in a 10bit 3Msps successive approximation ADC. This chip is realized with an SMIC 0. 18μm 1.8V process and occupies 0.25mm^2 . It consumes 3. 1mW when operating at 1.8MHz. The measured SINAD is 55. 9068dB, SFDR is 64. 5767dB, and THD is - 74. 8889dB when sampling a 320kHz sine wave.展开更多
In our previous theoretical study, the theoretical model of thecollision-induced electronic and rotational energy transfer of AB(~1Σ, J) + C(~sl_j) → AB(~1Σ,J′) + C(~sl_(j′)) was presented. To further study the c...In our previous theoretical study, the theoretical model of thecollision-induced electronic and rotational energy transfer of AB(~1Σ, J) + C(~sl_j) → AB(~1Σ,J′) + C(~sl_(j′)) was presented. To further study the collision-induced electronic and rotationalenergy transfer theoretically on AB( ~1Π, J) + C(~sl_j) → AB( ~1Π, J′) + C(~sl_(j′)), atheoretical model is presented, based on the time-dependent first-order Born approximation, takinginto account the anisotropic Lennard-Jones interaction potential and 'straight-line' trajectoryapproximation. The changing tendency of the transitional probabilities with the anisotropicparameter is discussed.展开更多
An asymptotic semi-analytical method for heat transfer in counter-flow honeycomb regenerator is proposed. By introducing a combined heat-transfer coefficient between the gas and solid phase, a heat transfer model is b...An asymptotic semi-analytical method for heat transfer in counter-flow honeycomb regenerator is proposed. By introducing a combined heat-transfer coefficient between the gas and solid phase, a heat transfer model is built based on the thin-walled assumption. The dimensionless thermal equation is deduced by considering solid heat conduction along the passage length. The asymptotic analysis is used for the small parameter of heat conduction term in equation. The first order asymptotic solution to temperature distribution under weak solid heat conduction is achieved after Laplace transformation through the multiple scales method and the symbolic manipulation function in MATLAB. Semi-analytical solutions agree with tests and finite-difference numerical results. It is proved possible for the asymptotic analysis to improve the effectiveness, economics and precision of thermal research on regenerator.展开更多
Nonlinear Rossby waves in a Boussinesq fluid model which includes both the vertical and horizontalcomponents of Coriolis force are studied by using the semi-geostrophic approximation and the method of travelling-waves...Nonlinear Rossby waves in a Boussinesq fluid model which includes both the vertical and horizontalcomponents of Coriolis force are studied by using the semi-geostrophic approximation and the method of travelling-wavesolution.Taylor series expansion has been employed to isolate the characteristics of the linear Rossby waves and identifythe Rossby cnoidal and solitary waves.Qualitative analysis indicates that if the disturbances are independent of latitude,the effect of horizontal components of Coriolis force disappears.展开更多
In this paper, an explicit Bgcklund transformation (BT) of the Burgers equation is obtained by using the further extended tanh method [Phys. Lett. A 307 (2003) 269; Chaos, Solitons & Fractals 17 (2003) 669]. Ba...In this paper, an explicit Bgcklund transformation (BT) of the Burgers equation is obtained by using the further extended tanh method [Phys. Lett. A 307 (2003) 269; Chaos, Solitons & Fractals 17 (2003) 669]. Based on the BT and some newly obtained seed solutions, infinite sequences of exact solutions for the Burgers equation are generated. Further more, this BT of the Burgers equation is applied to solve the variant Boussinesq equations and the approximate equations of long water wave.展开更多
In this paper, the integral-type Stancu operators on a simplex is considered and its inverse theorem of approximation in Lp(1≤ p 〈+∞)has been obtained.
The steady, laminar, incompressible and two dimensional micropolar flow between two porous disks was investigated using optimal homotopy asymptotic method(OHAM) and fourth order Runge–Kutta numerical method. Comparis...The steady, laminar, incompressible and two dimensional micropolar flow between two porous disks was investigated using optimal homotopy asymptotic method(OHAM) and fourth order Runge–Kutta numerical method. Comparison between OHAM and numerical method shows that OHAM is an exact and high efficient method for solving these kinds of problems. The results are presented to study the velocity and rotation profiles for different physical parameters such as Reynolds number, vortex viscosity parameter, spin gradient viscosity and microinertia density parameter. As an important outcome, the magnitude of the microrotation increases with an increase in the values of injection velocity while it decreases by increasing the values of suction velocity.展开更多
The conventional photoelectric detection system requires complex circuitry and spectroscopic systems as well as specialized personnel for its operation.To replace such a system,a method of measuring turbidity using a ...The conventional photoelectric detection system requires complex circuitry and spectroscopic systems as well as specialized personnel for its operation.To replace such a system,a method of measuring turbidity using a camera is proposed by combining the imaging characteristics of a digital camera and the high-speed information processing capability of a computer.Two turbidity measurement devices based on visible and near-infrared(NIR)light cameras and a light source driving circuit with constant light intensity were designed.The RGB data in the turbidity images were acquired using a self-developed image processing software and converted to the CIE Lab color space.Based on the relationship between the luminance,chromatic aberration,and turbidity,the turbidity detection models for luminance and chromatic aberration of visible and NIR light devices exhibiting values from 0-1000 NTU,less than 100 NTU,and more than 100 NTU were established.By comparing and analyzing the proposed models,the two measurement models with the best all-around performance were selected and fused to generate new measurement models.The experimental results prove that the correlation between the three models and the commercial turbidity meter measurements exhibite a significance value higher than 0.999.The error of the fusion model is within 1.05%,with a mean square error of 1.14.The visible light device has less error at low turbidity measurements and is less influenced by the color of the image.The NIR light device is more stable and accurate at full range and high turbidity measurements and is therefore more suitable for such measurements.展开更多
The dynamics of different kinds of discrete breathers in three types of one-dimensionai monatomic chains with on-site and inter-site potentiais are investigated. The existence and evolution of symmetric breather, anti...The dynamics of different kinds of discrete breathers in three types of one-dimensionai monatomic chains with on-site and inter-site potentiais are investigated. The existence and evolution of symmetric breather, antisymmetric breather, and multibreather in one-dimensionai models are proved by using rotating wave approximation, local anharmonic approximation, and the numerical method. The linear stability of these breathers is investigated by using Lyapunov stable anaiysis. The localization and stability of breathers in three types of models correlate closely to the system nonlinear parameter β.展开更多
In this paper, the dynamics of coherent laser control of potassium atoms is studied by using the time-dependent multilevel approach (TDMA). The calculation results of population transfer are presented with different...In this paper, the dynamics of coherent laser control of potassium atoms is studied by using the time-dependent multilevel approach (TDMA). The calculation results of population transfer are presented with different laser fields. The results show that the population can be transferred to target state completely by a specially designed laser field.展开更多
In order to study the collisional quantum interference (CQI) on rotational energy transfer in atom-diatom system, we have studied the relation of the integral interference angle and differential interference angle i...In order to study the collisional quantum interference (CQI) on rotational energy transfer in atom-diatom system, we have studied the relation of the integral interference angle and differential interference angle in Naq-Na2 (A1 ∑u^+,v=8-b^3∏0u,v=14) collision system. In this paper, based on the first-Born approximation of timedependent perturbation theory and taking into accounts the anisotropic effect of Lennard-Jones interaction potentials, we present a theoretical model of collisional quantum interference in intramolecular rotational energy transfer, and a relationship between differential and integral interference angles.展开更多
Following Jaynes-Cummings model,the evolution of the field entropy in the system of a two-level atom interacting with the single mode coherent field is investigated under rotating-wave approximation.The typical case &...Following Jaynes-Cummings model,the evolution of the field entropy in the system of a two-level atom interacting with the single mode coherent field is investigated under rotating-wave approximation.The typical case "the field frequency variance with time in the form of sine ω=ω0+usin(wt) has been considered.The influences of the amplitude and angle frequency of the field frequency variance on entropy evolution of the field are discussed by numerical calculations.Calculation results indicate that the field frequency variance influences violently the behavior of field entropy evolution;the larger the amplitude of the field frequency variance is,the stronger the influence of the field frequency variance on the time evolution of field entropy is.展开更多
文摘The singularly perturbed elliptic equation boundary value problem with turning point is considered. Using the method of multiple scales and the comparison theorem, the asymptotic behavior of solution for the boundary value problem is studied.
基金Projects (09-QZ-2008, 24-TZ-2009) supported by the Free Research Fund of State Key Laboratory of Solidification Processing, ChinaProject (B08040) supported by the Program of Introducing Talents of Discipline to Universities, China+3 种基金Projects (51071127, 51134011) supported by the National Natural Science Foundation of ChinaProject (JC200801) supported by the Fundamental Research Fund of Northwestern Polytechnical University, ChinaProject (51125002) supported by the National Science Foundation for Distinguished Young Scholars, ChinaProject (2011CB610403) supported by the National Basic Research Program of China
文摘Departing from an analytical phase transformation model, a new analytical approach to deduce transformed fraction for non-isothermal phase transformation was developed. In the new approach, the effect of the initial transformation temperature and the accurate "temperature integral" approximations are incorporated to obtain an extended analytical model. Numerical approach demonstrated that the extended analytical model prediction for transformed fraction and transformation rate is in good agreement with the exact numerical calculation. The new model can describe more precisely the kinetic behavior than the original analytical model, especially for transformation with relatively high initial transformation temperature. The kinetic parameters obtained from the new model are more accurate and reasonable than those from the original analytical model.
文摘A capacitor self-calibration circuit used in a successive approximation analog-to-digital converter (SA-ADC) is presented. This capacitor self-calibration circuit can calibrate erroneous data and work with the ADC by adding an additional clock period. This circuit is used in a 10 bit 32 Msample/s time-interleaved SA- ADC. The chip is implemented with Chart 0. 25 μm 2. 5 V process and totally occupies an area of 1.4 mm× 1.3 mm. After calibration, the simulated signal-to-noise ratio (SNR) is 59. 586 1 dB and the spurious-free dynamic range (SFDR) is 70. 246 dB at 32 MHz. The measured signal-to-noise and distortion ratio (SINAD) is 44. 82 dB and the SFDR is 63. 760 4 dB when the ADC samples a 5.8 MHz sinusoid wave.
文摘The atomic inversion dynamics in the mode-mode competing system is studied bymeans of fully quantum theory. A general solution to the Schroedinger equation of this system isobtained. The influence of the relative competing strength between the atom and the two-mode Geld onthe atomic inversion is disccussed. We show that the presence of the mode-mode competition canresult in periodical collapses-revivals of the atomic inversion.
基金Supported by the National Natural Science Foundation of China under Grant No. 40876010the Knowledge Innovation Project of Chinese Academy of Sciences under Grant No. KZCX2-YW-Q03-08+3 种基金the R & D Special Fund for Public Welfare Industry (meteorology) under Grant No. GYHY200806010the LASG State Key Laboratory Special Fundthe E-Institutes of Shanghai Municipal Education Commission under Grant No. E03004the Natural Science Foundation of Zhejiang Province under Grant No. Y6090164
文摘The corresponding solution for a class of disturbed KdV equation is considered using the analytic method. From the generalized variational iteration theory, the problem of solving soliton for the corresponding equation translates into the problem of variational iteration. And then the approximate solution of the soliton for the equation is obtained.
文摘Comparator offset cancellation and capacitor self-calibration techniques used in a successive approximation analog-to-digital converter (SA-ADC) are described. The calibration circuit works in parallel with the SAADC by adding additional calibration clock cycles to pursue high accuracy and low power consumption, and the calibrated resolution can be up to 14bit. This circuit is used in a 10bit 3Msps successive approximation ADC. This chip is realized with an SMIC 0. 18μm 1.8V process and occupies 0.25mm^2 . It consumes 3. 1mW when operating at 1.8MHz. The measured SINAD is 55. 9068dB, SFDR is 64. 5767dB, and THD is - 74. 8889dB when sampling a 320kHz sine wave.
文摘In our previous theoretical study, the theoretical model of thecollision-induced electronic and rotational energy transfer of AB(~1Σ, J) + C(~sl_j) → AB(~1Σ,J′) + C(~sl_(j′)) was presented. To further study the collision-induced electronic and rotationalenergy transfer theoretically on AB( ~1Π, J) + C(~sl_j) → AB( ~1Π, J′) + C(~sl_(j′)), atheoretical model is presented, based on the time-dependent first-order Born approximation, takinginto account the anisotropic Lennard-Jones interaction potential and 'straight-line' trajectoryapproximation. The changing tendency of the transitional probabilities with the anisotropicparameter is discussed.
基金Supported by Chinese National Programs for High Technology Research and Development (No. 2001AA514013)
文摘An asymptotic semi-analytical method for heat transfer in counter-flow honeycomb regenerator is proposed. By introducing a combined heat-transfer coefficient between the gas and solid phase, a heat transfer model is built based on the thin-walled assumption. The dimensionless thermal equation is deduced by considering solid heat conduction along the passage length. The asymptotic analysis is used for the small parameter of heat conduction term in equation. The first order asymptotic solution to temperature distribution under weak solid heat conduction is achieved after Laplace transformation through the multiple scales method and the symbolic manipulation function in MATLAB. Semi-analytical solutions agree with tests and finite-difference numerical results. It is proved possible for the asymptotic analysis to improve the effectiveness, economics and precision of thermal research on regenerator.
基金Supported by National Natural Science Foundation of China under Grant No.40475023
文摘Nonlinear Rossby waves in a Boussinesq fluid model which includes both the vertical and horizontalcomponents of Coriolis force are studied by using the semi-geostrophic approximation and the method of travelling-wavesolution.Taylor series expansion has been employed to isolate the characteristics of the linear Rossby waves and identifythe Rossby cnoidal and solitary waves.Qualitative analysis indicates that if the disturbances are independent of latitude,the effect of horizontal components of Coriolis force disappears.
基金中国博士后科学基金,国家重点基础研究发展计划(973计划),the National Key Basic Research Project of China under
文摘In this paper, an explicit Bgcklund transformation (BT) of the Burgers equation is obtained by using the further extended tanh method [Phys. Lett. A 307 (2003) 269; Chaos, Solitons & Fractals 17 (2003) 669]. Based on the BT and some newly obtained seed solutions, infinite sequences of exact solutions for the Burgers equation are generated. Further more, this BT of the Burgers equation is applied to solve the variant Boussinesq equations and the approximate equations of long water wave.
基金Supported by the NNSF of China(10371080)Supported by the Educational Committee Foundation of Beijing(01KJ-101)
文摘In this paper, the integral-type Stancu operators on a simplex is considered and its inverse theorem of approximation in Lp(1≤ p 〈+∞)has been obtained.
文摘The steady, laminar, incompressible and two dimensional micropolar flow between two porous disks was investigated using optimal homotopy asymptotic method(OHAM) and fourth order Runge–Kutta numerical method. Comparison between OHAM and numerical method shows that OHAM is an exact and high efficient method for solving these kinds of problems. The results are presented to study the velocity and rotation profiles for different physical parameters such as Reynolds number, vortex viscosity parameter, spin gradient viscosity and microinertia density parameter. As an important outcome, the magnitude of the microrotation increases with an increase in the values of injection velocity while it decreases by increasing the values of suction velocity.
基金National Natural Science Foundation of China(No.61671434)Key Projects of Provincial Natural Science Foundation of Anhui Universities(Nos.KJ2019A0952,KJ2017ZD32)。
文摘The conventional photoelectric detection system requires complex circuitry and spectroscopic systems as well as specialized personnel for its operation.To replace such a system,a method of measuring turbidity using a camera is proposed by combining the imaging characteristics of a digital camera and the high-speed information processing capability of a computer.Two turbidity measurement devices based on visible and near-infrared(NIR)light cameras and a light source driving circuit with constant light intensity were designed.The RGB data in the turbidity images were acquired using a self-developed image processing software and converted to the CIE Lab color space.Based on the relationship between the luminance,chromatic aberration,and turbidity,the turbidity detection models for luminance and chromatic aberration of visible and NIR light devices exhibiting values from 0-1000 NTU,less than 100 NTU,and more than 100 NTU were established.By comparing and analyzing the proposed models,the two measurement models with the best all-around performance were selected and fused to generate new measurement models.The experimental results prove that the correlation between the three models and the commercial turbidity meter measurements exhibite a significance value higher than 0.999.The error of the fusion model is within 1.05%,with a mean square error of 1.14.The visible light device has less error at low turbidity measurements and is less influenced by the color of the image.The NIR light device is more stable and accurate at full range and high turbidity measurements and is therefore more suitable for such measurements.
基金Supported by the National Natural Science Foundation of China under Grant No.1057411 the Foundation for Researching Group by Beijing Normal University
文摘The dynamics of different kinds of discrete breathers in three types of one-dimensionai monatomic chains with on-site and inter-site potentiais are investigated. The existence and evolution of symmetric breather, antisymmetric breather, and multibreather in one-dimensionai models are proved by using rotating wave approximation, local anharmonic approximation, and the numerical method. The linear stability of these breathers is investigated by using Lyapunov stable anaiysis. The localization and stability of breathers in three types of models correlate closely to the system nonlinear parameter β.
基金Project supported by the Natural Science Foundation of Henan province, China (Grant No 0411011900).
文摘In this paper, the dynamics of coherent laser control of potassium atoms is studied by using the time-dependent multilevel approach (TDMA). The calculation results of population transfer are presented with different laser fields. The results show that the population can be transferred to target state completely by a specially designed laser field.
基金Supported by the National Natural Science Foundation of China under Grant No.10374040the Foundation of the Educational Department of Liaoning Province under Grant Nos.2008290 and 20060347
文摘In order to study the collisional quantum interference (CQI) on rotational energy transfer in atom-diatom system, we have studied the relation of the integral interference angle and differential interference angle in Naq-Na2 (A1 ∑u^+,v=8-b^3∏0u,v=14) collision system. In this paper, based on the first-Born approximation of timedependent perturbation theory and taking into accounts the anisotropic effect of Lennard-Jones interaction potentials, we present a theoretical model of collisional quantum interference in intramolecular rotational energy transfer, and a relationship between differential and integral interference angles.
基金Natural Science Foundation of Fujian Province under Grant(No.2008J0217)
文摘Following Jaynes-Cummings model,the evolution of the field entropy in the system of a two-level atom interacting with the single mode coherent field is investigated under rotating-wave approximation.The typical case "the field frequency variance with time in the form of sine ω=ω0+usin(wt) has been considered.The influences of the amplitude and angle frequency of the field frequency variance on entropy evolution of the field are discussed by numerical calculations.Calculation results indicate that the field frequency variance influences violently the behavior of field entropy evolution;the larger the amplitude of the field frequency variance is,the stronger the influence of the field frequency variance on the time evolution of field entropy is.