The acceleration of LMXB 4U 1820-30 derived from its orbital-period derivative P_(b)was supposed to be the evidence for an Intermediate-mass black hole(IMBH)in the Galactic globular cluster(GC)NGC 6624.However,we find...The acceleration of LMXB 4U 1820-30 derived from its orbital-period derivative P_(b)was supposed to be the evidence for an Intermediate-mass black hole(IMBH)in the Galactic globular cluster(GC)NGC 6624.However,we find that the anomalous P_(b)is mainly due to the gravitational wave emission,rather than the acceleration in cluster potential.Using the standard structure models of GCs,we simulate acceleration distributions for pulsars in the central region of the cluster.By fitting the acceleration of J1823-3021 A with the simulated distribution profiles(maximum values),it is suggested that an IMBH with mass M■950_(-350)^(+550)M_(⊙) may reside in the cluster center.We further show that the second period derivative P of J1823-3021 A is probably due to the gravitational perturbation of a nearby star.展开更多
(ZrMg)xY2-2xMo3O12(x=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,and 1)ceramics have been synthesized to obtain less hygroscopicity and negative thermal expansion.With increasing the substitution of(ZrMg)^6+(ion radius 7....(ZrMg)xY2-2xMo3O12(x=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,and 1)ceramics have been synthesized to obtain less hygroscopicity and negative thermal expansion.With increasing the substitution of(ZrMg)^6+(ion radius 7.2×10^-11 m)for Y3+(ion radius 9×10^-11 m),the crystal water are reduced obviously.The linear thermal expansion coefficient is improved with increasing the content of(ZrMg)^6+.The material shows near zero thermal expansion(-0.12×10^-6 K^-1,430-870 K)with x=0.7.Meanwhile,ZrMgMo3O12 shows low non-hygroscopicity and negative thermal expansion,but low softening temperature.After substituting amount of Y^3+for(ZrMg)^6+in ZrMgMo3O12(x=0.8),the softening temperature increases remarkably(750 K to 830 K)and it presents near zero thermal expansion.展开更多
The form of timing residuals due to errors in pulsar spin period P and its derivative P, in positions, as well as in proper motions, has been well presented for decades in the literature. However,the residual patterns...The form of timing residuals due to errors in pulsar spin period P and its derivative P, in positions, as well as in proper motions, has been well presented for decades in the literature. However,the residual patterns due to errors in the pulsar acceleration have not been reported previously, while a pulsar in the Galaxy or a globular cluster(GC) will be unavoidably accelerated. The coupling effect of the pulsar transverse acceleration and the R¨omer delay on timing residuals is simulated in this work. The results demonstrate that the residuals due to the effect can be identified by the oscillation envelopes of the residuals. It is also shown that the amplitude of the residuals due to the effect is usually relatively small,however, it may probably be observable for pulsars distributed in the vicinity of the core of a nearby GC.展开更多
The polymethyl methacrylate （PMMA） film doped with an azo dye ethyl-red （ER） film is employed to demonstrate the properties of an all-optical switch by its photoinduced dichroism and birefringence. We show how to ...The polymethyl methacrylate （PMMA） film doped with an azo dye ethyl-red （ER） film is employed to demonstrate the properties of an all-optical switch by its photoinduced dichroism and birefringence. We show how to enhance remarkably the modulation depth of all-optical switches almost to 100% by using two linear polarization beams： one beam is inclined at 45° with respect to the probing beam and serves as a pumping beam, and the other beam is perpendicular to the probing beam and used as an erasing beam. Furthermore, a maximum-to-minimum output intensity ratio of 2000：1 is achieved in experiment, which is very useful and important for optical storages and image displays.展开更多
A new scheme for fabricating a kind of flexible semiconductor micro-laser is put forward.And the optical properties of this kind of flexible semiconductor laser are investigated by the finite difference time domain(FD...A new scheme for fabricating a kind of flexible semiconductor micro-laser is put forward.And the optical properties of this kind of flexible semiconductor laser are investigated by the finite difference time domain(FDTD) method.The results show that the light should be localized by photonic crystals(PCs),and the interaction between light and gain medium should be enhanced,while the mode of laser should be modulated.These results indicate that the PCs could control the spontaneous emission,and lead the radiation emission to the needed frequency.展开更多
We investigate pulsar timing residuals due to the coupling effect of the pulsar transverse acceleration and the Romer delay.The effect is relatively small and usually negligible.Only for pulsars in globular clusters,i...We investigate pulsar timing residuals due to the coupling effect of the pulsar transverse acceleration and the Romer delay.The effect is relatively small and usually negligible.Only for pulsars in globular clusters,it is possibly important.The maximum residual amplitude,which is from the pulsar near the surface of the core of the cluster,is about tens of nanoseconds,and may hardly be identified for most globular clusters currently.However,an intermediate-mass black hole in the center of a cluster can apparently increase the timing residual magnitudes.Particularly for pulsars in the innermost core region,their residual magnitudes may be significant.The high-magnitude residuals,which are above critical lines of each cluster,are strong evidence for the presence of a black hole or dark remnants of comparable total mass in the center of the cluster.We also explored the timing effects of line-of-sight accelerations for the pulsars.The distribution of measured line-of-sight accelerations are simulated with a Monte Carlo method.Two-dimensional Kolmogorov-Smirnov tests are performed to reexamine the consistency of distributions of the simulated and reported data for various values of parameters of the clusters.It is shown that the structure parameters of Terzan 5 can be constrained well by comparing the distribution of measured lineof-sight accelerations with the distributions from Monte Carlo simulations.We find that the cluster has an upper limit on the central black hole/dark remnant mass of~6000 M⊙.展开更多
We investigate the behavior of two-dimensional atom localization in an inverted-Y system driven by one coherent field and two standing-wave fields.The position probability distribution of the atom passing through the ...We investigate the behavior of two-dimensional atom localization in an inverted-Y system driven by one coherent field and two standing-wave fields.The position probability distribution of the atom passing through the spatial-position-dependent standing-wave fields can be determined by measuring the spontaneously emitted photon.It is found that high-precision two-dimensional atom localization can be obtained by choosing appropriate system parameters.展开更多
基金supported by the National Natural Science Foundation of China under Grant Nos.11803009 and 11603009the Natural Science Foundation of Fujian Province under Grant Nos.2018J05006,2018J01416 and 2016J05013。
文摘The acceleration of LMXB 4U 1820-30 derived from its orbital-period derivative P_(b)was supposed to be the evidence for an Intermediate-mass black hole(IMBH)in the Galactic globular cluster(GC)NGC 6624.However,we find that the anomalous P_(b)is mainly due to the gravitational wave emission,rather than the acceleration in cluster potential.Using the standard structure models of GCs,we simulate acceleration distributions for pulsars in the central region of the cluster.By fitting the acceleration of J1823-3021 A with the simulated distribution profiles(maximum values),it is suggested that an IMBH with mass M■950_(-350)^(+550)M_(⊙) may reside in the cluster center.We further show that the second period derivative P of J1823-3021 A is probably due to the gravitational perturbation of a nearby star.
基金Funded by National Natural Science Foundation of China(Nos.61704156,11847099 and 10974183).
文摘(ZrMg)xY2-2xMo3O12(x=0.0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8,0.9,and 1)ceramics have been synthesized to obtain less hygroscopicity and negative thermal expansion.With increasing the substitution of(ZrMg)^6+(ion radius 7.2×10^-11 m)for Y3+(ion radius 9×10^-11 m),the crystal water are reduced obviously.The linear thermal expansion coefficient is improved with increasing the content of(ZrMg)^6+.The material shows near zero thermal expansion(-0.12×10^-6 K^-1,430-870 K)with x=0.7.Meanwhile,ZrMgMo3O12 shows low non-hygroscopicity and negative thermal expansion,but low softening temperature.After substituting amount of Y^3+for(ZrMg)^6+in ZrMgMo3O12(x=0.8),the softening temperature increases remarkably(750 K to 830 K)and it presents near zero thermal expansion.
基金supported by the National Natural Science Foundation of China(Grant Nos.11803009 and 11603009)the Natural Science Foundation of Fujian Province(Grant Nos.2018J05006,2018J01416 and 2016J05013)。
文摘The form of timing residuals due to errors in pulsar spin period P and its derivative P, in positions, as well as in proper motions, has been well presented for decades in the literature. However,the residual patterns due to errors in the pulsar acceleration have not been reported previously, while a pulsar in the Galaxy or a globular cluster(GC) will be unavoidably accelerated. The coupling effect of the pulsar transverse acceleration and the R¨omer delay on timing residuals is simulated in this work. The results demonstrate that the residuals due to the effect can be identified by the oscillation envelopes of the residuals. It is also shown that the amplitude of the residuals due to the effect is usually relatively small,however, it may probably be observable for pulsars distributed in the vicinity of the core of a nearby GC.
基金Project supported by the National Natural Science Foundation of China(Grant No.10774152)the Science and Technology Foundation of Guangzhou City,China(Grant No.2008J1-C021) the Research Fund for the Doctoral Program of Higher Education of China(Grant No.20070055103)
文摘The polymethyl methacrylate （PMMA） film doped with an azo dye ethyl-red （ER） film is employed to demonstrate the properties of an all-optical switch by its photoinduced dichroism and birefringence. We show how to enhance remarkably the modulation depth of all-optical switches almost to 100% by using two linear polarization beams： one beam is inclined at 45° with respect to the probing beam and serves as a pumping beam, and the other beam is perpendicular to the probing beam and used as an erasing beam. Furthermore, a maximum-to-minimum output intensity ratio of 2000：1 is achieved in experiment, which is very useful and important for optical storages and image displays.
基金supported by the National Natural Science Foundation of China (Nos.60768001 and 60808019)the Natural Science Foundation of Jiangxi Province (No. 2010gzw0045)
文摘A new scheme for fabricating a kind of flexible semiconductor micro-laser is put forward.And the optical properties of this kind of flexible semiconductor laser are investigated by the finite difference time domain(FDTD) method.The results show that the light should be localized by photonic crystals(PCs),and the interaction between light and gain medium should be enhanced,while the mode of laser should be modulated.These results indicate that the PCs could control the spontaneous emission,and lead the radiation emission to the needed frequency.
基金the National Natural Science Foundation of China(Grant Nos.11803009 and 11603009)the Natural Science Foundation of Fujian Province(Grant Nos.2018J05006,2018J01416 and 2016J05013).
文摘We investigate pulsar timing residuals due to the coupling effect of the pulsar transverse acceleration and the Romer delay.The effect is relatively small and usually negligible.Only for pulsars in globular clusters,it is possibly important.The maximum residual amplitude,which is from the pulsar near the surface of the core of the cluster,is about tens of nanoseconds,and may hardly be identified for most globular clusters currently.However,an intermediate-mass black hole in the center of a cluster can apparently increase the timing residual magnitudes.Particularly for pulsars in the innermost core region,their residual magnitudes may be significant.The high-magnitude residuals,which are above critical lines of each cluster,are strong evidence for the presence of a black hole or dark remnants of comparable total mass in the center of the cluster.We also explored the timing effects of line-of-sight accelerations for the pulsars.The distribution of measured line-of-sight accelerations are simulated with a Monte Carlo method.Two-dimensional Kolmogorov-Smirnov tests are performed to reexamine the consistency of distributions of the simulated and reported data for various values of parameters of the clusters.It is shown that the structure parameters of Terzan 5 can be constrained well by comparing the distribution of measured lineof-sight accelerations with the distributions from Monte Carlo simulations.We find that the cluster has an upper limit on the central black hole/dark remnant mass of~6000 M⊙.
基金Supported by the National Natural Science Foundation of China under Grant Nos 60768001,10464002,61168001。
文摘We investigate the behavior of two-dimensional atom localization in an inverted-Y system driven by one coherent field and two standing-wave fields.The position probability distribution of the atom passing through the spatial-position-dependent standing-wave fields can be determined by measuring the spontaneously emitted photon.It is found that high-precision two-dimensional atom localization can be obtained by choosing appropriate system parameters.
