We investigate the adiabatic enhanced compression of ultrashort pulses from a distributed feedback laser operated at 1550 nm in fibres with slowly decreasing dispersion (FSDD). High-quality pulse compressions from 4.4...We investigate the adiabatic enhanced compression of ultrashort pulses from a distributed feedback laser operated at 1550 nm in fibres with slowly decreasing dispersion (FSDD). High-quality pulse compressions from 4.4 ps down to 1.1ps in a l00m FSDD and from 4.4ps down to 830fs in a 500m FSDD are obtained. The Raman self frequency shift of femtosecond pulses in the compression is observed. Theoretical analyses are in good agreement with experimental results.展开更多
A double perturbation strategy is presented to solve the asymptotic solutions of a Johnson-Segalman （J-S） fluid through a slowly varying pipe. First, a small parameter of the slowly varying angle is taken as the sma...A double perturbation strategy is presented to solve the asymptotic solutions of a Johnson-Segalman （J-S） fluid through a slowly varying pipe. First, a small parameter of the slowly varying angle is taken as the small perturbation parameter, and then the second-order asymptotic solution of the flow of a Newtonian fluid through a slowly varying pipe is obtained in the first perturbation strategy. Second, the viscoelastic parameter is selected as the small perturbation parameter in the second perturbation strategy to solve the asymptotic solution of the flow of a J-S fluid through a slowly varying pipe. Finally, the parameter effects, including the axial distance, the slowly varying angle, and the Reynolds number, on the velocity distributions are analyzed. The results show that the increases in both the axial distance and the slowly varying angle make the axial velocity slow down. However, the radial velocity increases with the slowly varying angle, and decreases with the axial distance. There are two special positions in the distribution curves of the axial velocity and the radial velocity with different Reynolds numbers, and there are different trends on both sides of the special positions. The double perturbation strategy is applicable to such problems with the flow of a non-Newtonian fluid through a slowly varying pipe.展开更多
Using the thin film brick-wall model and WKB approximation, the entropy of the Dirac field in the non-stationary and slowly changing Reissner-Nordstrom (R-N) black hole is calculated. The result shows that the entropy...Using the thin film brick-wall model and WKB approximation, the entropy of the Dirac field in the non-stationary and slowly changing Reissner-Nordstrom (R-N) black hole is calculated. The result shows that the entropy of the R-N black hole is still proportional to its surface area if we choose proper cut-off.展开更多
The evolution of Asian summer monsoon is analyzed by means of decomposition of the atmospheric circulationinto basic current and slowly varying monsoon disturbances. It is seen that the major slowly varying disturbanc...The evolution of Asian summer monsoon is analyzed by means of decomposition of the atmospheric circulationinto basic current and slowly varying monsoon disturbances. It is seen that the major slowly varying disturbances aretwo vortical couples, one located in the indian Ocean and indian Peninsula, and another in the Northern Hemisphericwestern Pacific Ocean and the East Asia. This indicates that the Asian summer monsoon consists of two branches, theIndian monsoon and the East Asian monsoon. Moreover, the analysis shows that the evolutionary processes of thesetwo vortical couples are rather independent each other, and they all can be qualitatively interpreted by the dynamicaltheory of wave packet. The different stages of summer monsoon can be very well characterized by the location and in-tensity of the two vortical couples. Besides, in particular years there exists also some quasistationary wave train andits characteristics should be further analyzed.展开更多
The stabilization problem of systems that switch among a finite set of slowly varying linear systems with arbitrary switching frequency is discussed.It is shown that if the entries of the pointwise stabilizing feedbac...The stabilization problem of systems that switch among a finite set of slowly varying linear systems with arbitrary switching frequency is discussed.It is shown that if the entries of the pointwise stabilizing feedback gain matrix are continuously differentiable functions of the entries of the system coefficient matrices,then the closed-loop system is uniformly asymptotically stable if the rate of time variation of the system coefficient matrices is sufficiently small.展开更多
By using a weakly nonlinear and perturbation method, the generalized inhomogeneous Korteweg de Vries （KdV）- Burgers equation is derived, which governs the evolution of the amplitude of Rossby waves under the influen...By using a weakly nonlinear and perturbation method, the generalized inhomogeneous Korteweg de Vries （KdV）- Burgers equation is derived, which governs the evolution of the amplitude of Rossby waves under the influence of dissipation and slowly varying topography with time. The analysis indicates that dissipation and slowly varying topography with time are important factors in causing variation in the mass and energy of solitary waves.展开更多
In this paper we study the asymptotic expansions of the solutions for a class of second order ordinary differential equations with slowly varying coefficients. The defect of the known works on these problems is noted,...In this paper we study the asymptotic expansions of the solutions for a class of second order ordinary differential equations with slowly varying coefficients. The defect of the known works on these problems is noted, and the results in [1 - 4] are improved and extended by means of the modified method of multiple scales.展开更多
According to CAAM,during the first half year of 2014,the sales of buses have grown slowly.The production and sales of passenger vehicle amount to 274thousand units and 279 thousand units respectively,up by 2.49%and 4....According to CAAM,during the first half year of 2014,the sales of buses have grown slowly.The production and sales of passenger vehicle amount to 274thousand units and 279 thousand units respectively,up by 2.49%and 4.31%.Overall increase of bus sales According to Gasgoo,during the first haft year the sale of buses(whole vehicle)has accumulated sales of 243.1thousand units,up by 7.0%year on year.The first three months have seen展开更多
In this paper we consider polynomial splines S(x) with equidistant nodes which may grow a5 O (|x|~5). We present an integral representation of such splines with a distribution kernel. This repre- sentation is related ...In this paper we consider polynomial splines S(x) with equidistant nodes which may grow a5 O (|x|~5). We present an integral representation of such splines with a distribution kernel. This repre- sentation is related to the Fourier integral of slowly growing functions. The part of the Fourier ex- ponentials herewith play the so called exponential splines by Schoenberg. The integral representation provides a flexible tool for dealing with the growing equidistant splines. First. it allows us to con- struct a rich library of splines possessing the property that translations of any such spline form a ba- sis of corresponding spline space. It is shown that any such spline is associated with a dual spline whose translations form a biorthogonal basis. As examples we present solutions of the problems of projection of a growing function onto spline spaces and of spline interpolation of growing func- tion. We derive formulas for approximate evaluation of splines projecting a function onto the spline space and establish therewith exact estimations of the approximation errors.展开更多
Genomic instability after radiation is the main reason of the increase of malignancy degree and normal tissuetransformation[1]. Previous study indicated that bystander cells show more long-term genomic instability aft...Genomic instability after radiation is the main reason of the increase of malignancy degree and normal tissuetransformation[1]. Previous study indicated that bystander cells show more long-term genomic instability afterradiation[2].In this study, non-small cell lung cancer cell line (A549) was radiated with X-rays (30 kV of 2 Gy), and theconditioned medium was transferred to bystander cells. The fast and slowly proliferating populations in bystandercells were isolated by the colony formation assay. After one month, the chromosome number (Table 1, Fig. 1),drug resistance ability (Fig. 2) and cancer stem-like cell enrichment (Fig. 3) were investigated in fast and slowlyproliferating cells, respectively.展开更多
On the basis of the wave energy balance equation, the response model of mean directions of locally wind-generated waves in slowly turning wind fields has been derived. The results show that in a homogeneous field, the...On the basis of the wave energy balance equation, the response model of mean directions of locally wind-generated waves in slowly turning wind fields has been derived. The results show that in a homogeneous field, the time scale of the response is not only related to the rate of wave growth, but also to the directional energy distribution and the angle between the wind direction and the mean wave direction. Furthermore, the law of change in the mean wave direction has been derived. The numerical computations show that the response of wave directions to slowly turning wind directions can be treated as the superposition of the responses of wave directions to a series of sudden small-angle changes of wind directions and the turning rate of the mean wave direction depends on the turning rate and the total turning angles of the wind direction. The response of wave directions is in agreement with the response for a sudden change of wind directions if the change in wind directions is very fast. Based on the normalized rates of wave growth under local winds presented by Wen et al. (1989), a quantitative estimate of the time scale of the response shows that the relationships between the dimensionless time scale and both the dimensionless total wave energy and the dimensionless peak frequency agree fairly well with the observations in comparison with other models.展开更多
Under the condition that any perfeetly plastic stress components at a crack tip are nothing but the Junctions of 0 only, making use of equilibriumequations,Hill ani.sutropic yield condition and unloading stress-strain...Under the condition that any perfeetly plastic stress components at a crack tip are nothing but the Junctions of 0 only, making use of equilibriumequations,Hill ani.sutropic yield condition and unloading stress-strain relations, in this paper, we derive the general analytical expressions of anisotropic plastiestress Jields at the slowly steadyhe slowly steady propagatin tips of plane and anti-phane strain,Applying these general analytical expressions to the concrete cracks the attchvtical expressions of anisotropie plastic stress fields at the slowly steady propagating tips of Motle I and Motle III cracks are obtained. For the isolropic plastic material, the anisotropic plastic stress fields at a slowly propagating crack tip become the perfeeby plastic mress fields展开更多
在现代英语中,slow与slowly都可以用作副词,表示“缓慢地;慢慢地”的意思,有时可互换作用。例如: How slow(ly)the time passes.时间过得多慢啊. You should go slow(ly)through the bridge. 过桥时你应缓行。但是,在实际使用过程中,还...在现代英语中,slow与slowly都可以用作副词,表示“缓慢地;慢慢地”的意思,有时可互换作用。例如: How slow(ly)the time passes.时间过得多慢啊. You should go slow(ly)through the bridge. 过桥时你应缓行。但是,在实际使用过程中,还应注意以下各点: 一、在口语中,特别是在美国英语中,slow往往比slowly常用,且语气强。例如:展开更多
The nonlinear waves in a stratified fluid of slowly varying depth are investigated in this paper.The model considered here consists of a two-layer incompressible constant-density inviscid fluid confined by a slightly ...The nonlinear waves in a stratified fluid of slowly varying depth are investigated in this paper.The model considered here consists of a two-layer incompressible constant-density inviscid fluid confined by a slightly uneven bottom and a horizontal rigid wall.The Korteweg-de Vries(KdV)equation with varying coefficients is derived with the aid of the reductive perturbation method.By using the method of multiple scales,the approximate solutions of this equation are obtained.It is found that the unevenness of bottom may lead to the generation of socalled quasi-periodic waves and quasi-solitary waves,whose periods,propagation velocities and wave profiles vary slowly.The relations of the period of quasi-periodic waves and of the amplitude,propagation velocity of quasi-solitary waves varying with the depth of fluid are also presented.The models with two horizontal rigid walls or single-layer fluid can be regarded as particular cases of those in this paper.展开更多
基金Supported by the Natural Science Foundation of the Guangdong Education Department(200019)the Natural Science Foundation of Guangdong Province(980030).
文摘We investigate the adiabatic enhanced compression of ultrashort pulses from a distributed feedback laser operated at 1550 nm in fibres with slowly decreasing dispersion (FSDD). High-quality pulse compressions from 4.4 ps down to 1.1ps in a l00m FSDD and from 4.4ps down to 830fs in a 500m FSDD are obtained. The Raman self frequency shift of femtosecond pulses in the compression is observed. Theoretical analyses are in good agreement with experimental results.
基金supported by the National Natural Science Foundation of China(Nos.11572203 and11332006)
文摘A double perturbation strategy is presented to solve the asymptotic solutions of a Johnson-Segalman （J-S） fluid through a slowly varying pipe. First, a small parameter of the slowly varying angle is taken as the small perturbation parameter, and then the second-order asymptotic solution of the flow of a Newtonian fluid through a slowly varying pipe is obtained in the first perturbation strategy. Second, the viscoelastic parameter is selected as the small perturbation parameter in the second perturbation strategy to solve the asymptotic solution of the flow of a J-S fluid through a slowly varying pipe. Finally, the parameter effects, including the axial distance, the slowly varying angle, and the Reynolds number, on the velocity distributions are analyzed. The results show that the increases in both the axial distance and the slowly varying angle make the axial velocity slow down. However, the radial velocity increases with the slowly varying angle, and decreases with the axial distance. There are two special positions in the distribution curves of the axial velocity and the radial velocity with different Reynolds numbers, and there are different trends on both sides of the special positions. The double perturbation strategy is applicable to such problems with the flow of a non-Newtonian fluid through a slowly varying pipe.
文摘Using the thin film brick-wall model and WKB approximation, the entropy of the Dirac field in the non-stationary and slowly changing Reissner-Nordstrom (R-N) black hole is calculated. The result shows that the entropy of the R-N black hole is still proportional to its surface area if we choose proper cut-off.
文摘The evolution of Asian summer monsoon is analyzed by means of decomposition of the atmospheric circulationinto basic current and slowly varying monsoon disturbances. It is seen that the major slowly varying disturbances aretwo vortical couples, one located in the indian Ocean and indian Peninsula, and another in the Northern Hemisphericwestern Pacific Ocean and the East Asia. This indicates that the Asian summer monsoon consists of two branches, theIndian monsoon and the East Asian monsoon. Moreover, the analysis shows that the evolutionary processes of thesetwo vortical couples are rather independent each other, and they all can be qualitatively interpreted by the dynamicaltheory of wave packet. The different stages of summer monsoon can be very well characterized by the location and in-tensity of the two vortical couples. Besides, in particular years there exists also some quasistationary wave train andits characteristics should be further analyzed.
文摘The stabilization problem of systems that switch among a finite set of slowly varying linear systems with arbitrary switching frequency is discussed.It is shown that if the entries of the pointwise stabilizing feedback gain matrix are continuously differentiable functions of the entries of the system coefficient matrices,then the closed-loop system is uniformly asymptotically stable if the rate of time variation of the system coefficient matrices is sufficiently small.
基金supported by the Knowledge Innovation Key Program of the Chinese Academy of Sciences (Grant No. KZCX1-YW-12)the National Key Science Foundation of China (Grant No. 41030855)
文摘By using a weakly nonlinear and perturbation method, the generalized inhomogeneous Korteweg de Vries （KdV）- Burgers equation is derived, which governs the evolution of the amplitude of Rossby waves under the influence of dissipation and slowly varying topography with time. The analysis indicates that dissipation and slowly varying topography with time are important factors in causing variation in the mass and energy of solitary waves.
基金The Project Supported by the National Natural Science Foundation of China
文摘In this paper we study the asymptotic expansions of the solutions for a class of second order ordinary differential equations with slowly varying coefficients. The defect of the known works on these problems is noted, and the results in [1 - 4] are improved and extended by means of the modified method of multiple scales.
文摘According to CAAM,during the first half year of 2014,the sales of buses have grown slowly.The production and sales of passenger vehicle amount to 274thousand units and 279 thousand units respectively,up by 2.49%and 4.31%.Overall increase of bus sales According to Gasgoo,during the first haft year the sale of buses(whole vehicle)has accumulated sales of 243.1thousand units,up by 7.0%year on year.The first three months have seen
文摘In this paper we consider polynomial splines S(x) with equidistant nodes which may grow a5 O (|x|~5). We present an integral representation of such splines with a distribution kernel. This repre- sentation is related to the Fourier integral of slowly growing functions. The part of the Fourier ex- ponentials herewith play the so called exponential splines by Schoenberg. The integral representation provides a flexible tool for dealing with the growing equidistant splines. First. it allows us to con- struct a rich library of splines possessing the property that translations of any such spline form a ba- sis of corresponding spline space. It is shown that any such spline is associated with a dual spline whose translations form a biorthogonal basis. As examples we present solutions of the problems of projection of a growing function onto spline spaces and of spline interpolation of growing func- tion. We derive formulas for approximate evaluation of splines projecting a function onto the spline space and establish therewith exact estimations of the approximation errors.
文摘Genomic instability after radiation is the main reason of the increase of malignancy degree and normal tissuetransformation[1]. Previous study indicated that bystander cells show more long-term genomic instability afterradiation[2].In this study, non-small cell lung cancer cell line (A549) was radiated with X-rays (30 kV of 2 Gy), and theconditioned medium was transferred to bystander cells. The fast and slowly proliferating populations in bystandercells were isolated by the colony formation assay. After one month, the chromosome number (Table 1, Fig. 1),drug resistance ability (Fig. 2) and cancer stem-like cell enrichment (Fig. 3) were investigated in fast and slowlyproliferating cells, respectively.
文摘On the basis of the wave energy balance equation, the response model of mean directions of locally wind-generated waves in slowly turning wind fields has been derived. The results show that in a homogeneous field, the time scale of the response is not only related to the rate of wave growth, but also to the directional energy distribution and the angle between the wind direction and the mean wave direction. Furthermore, the law of change in the mean wave direction has been derived. The numerical computations show that the response of wave directions to slowly turning wind directions can be treated as the superposition of the responses of wave directions to a series of sudden small-angle changes of wind directions and the turning rate of the mean wave direction depends on the turning rate and the total turning angles of the wind direction. The response of wave directions is in agreement with the response for a sudden change of wind directions if the change in wind directions is very fast. Based on the normalized rates of wave growth under local winds presented by Wen et al. (1989), a quantitative estimate of the time scale of the response shows that the relationships between the dimensionless time scale and both the dimensionless total wave energy and the dimensionless peak frequency agree fairly well with the observations in comparison with other models.
文摘Under the condition that any perfeetly plastic stress components at a crack tip are nothing but the Junctions of 0 only, making use of equilibriumequations,Hill ani.sutropic yield condition and unloading stress-strain relations, in this paper, we derive the general analytical expressions of anisotropic plastiestress Jields at the slowly steadyhe slowly steady propagatin tips of plane and anti-phane strain,Applying these general analytical expressions to the concrete cracks the attchvtical expressions of anisotropie plastic stress fields at the slowly steady propagating tips of Motle I and Motle III cracks are obtained. For the isolropic plastic material, the anisotropic plastic stress fields at a slowly propagating crack tip become the perfeeby plastic mress fields
文摘在现代英语中,slow与slowly都可以用作副词,表示“缓慢地;慢慢地”的意思,有时可互换作用。例如: How slow(ly)the time passes.时间过得多慢啊. You should go slow(ly)through the bridge. 过桥时你应缓行。但是,在实际使用过程中,还应注意以下各点: 一、在口语中,特别是在美国英语中,slow往往比slowly常用,且语气强。例如:
基金Project Supported by National Natural Science Foundation of China
文摘The nonlinear waves in a stratified fluid of slowly varying depth are investigated in this paper.The model considered here consists of a two-layer incompressible constant-density inviscid fluid confined by a slightly uneven bottom and a horizontal rigid wall.The Korteweg-de Vries(KdV)equation with varying coefficients is derived with the aid of the reductive perturbation method.By using the method of multiple scales,the approximate solutions of this equation are obtained.It is found that the unevenness of bottom may lead to the generation of socalled quasi-periodic waves and quasi-solitary waves,whose periods,propagation velocities and wave profiles vary slowly.The relations of the period of quasi-periodic waves and of the amplitude,propagation velocity of quasi-solitary waves varying with the depth of fluid are also presented.The models with two horizontal rigid walls or single-layer fluid can be regarded as particular cases of those in this paper.
