We present a robust （n, n）-threshold scheme for multiparty quantum secret sharing of key over two collectivenoise channels （i.e., the collective dephasing channel and the collective rotating channel） via three-pho...We present a robust （n, n）-threshold scheme for multiparty quantum secret sharing of key over two collectivenoise channels （i.e., the collective dephasing channel and the collective rotating channel） via three-photon mixed states, In our scheme, only if all the sharers collaborate together can they establish a joint key with the message sender and extract the secret message from the sender＇s encrypted message. This scheme can be implemented using only a Bell singlet, a one-qubit state and polarization identification of single photon, so it is completely feasible according to the present-day technique.展开更多
Because of the quantization noise introduced during the compression,super-resolution reconstruction(SRR)techniques are complicated for the compressed images.This paper aims to incorporate the prior knowledge of discre...Because of the quantization noise introduced during the compression,super-resolution reconstruction(SRR)techniques are complicated for the compressed images.This paper aims to incorporate the prior knowledge of discrete cosine transform(DCT)coefficients into modeling the quantization noise.The spatial covariance matrix of the quantization noise is estimated by utilizing the Laplacian distribution of the alternating current(AC)coefficients.After estimating the spatial joint covariance of overall noises for the imaging system,we propose a general Bayesian framework to enhance the resolution for compressed images.Experiments demonstrate the effectiveness of the proposed algorithm and show the superiority to previous methods in objective and subjective aspects.展开更多
A two-dimensional generalized Langevin equation is proposed to describe the protein conformational change, compatible to the electron transfer process governed by atomic packing density model. We assume a fractional G...A two-dimensional generalized Langevin equation is proposed to describe the protein conformational change, compatible to the electron transfer process governed by atomic packing density model. We assume a fractional Gaussian noise and a white noise through bond and through space coordinates respectively, and introduce the coupling effect coming from both fluctuations and equilibrium variances. The general expressions for autocorrelation functions of distance fluctuation and fluorescence lifetime variation are derived, based on which the exact conformational change dynamics can be evaluated with the aid of numerical Laplace inversion technique. We explicitly elaborate the short time and long time approximations. The relationship between the two-diraensional description and the one-dimensional theory is also discussed.展开更多
Spatial correlation of sound pressure and particle velocity of the surface noise in horizontally stratified media was demonstrated, with directional noise sources uniformly distributed on the ocean surface. In the eva...Spatial correlation of sound pressure and particle velocity of the surface noise in horizontally stratified media was demonstrated, with directional noise sources uniformly distributed on the ocean surface. In the evaluation of particle velocity, plane wave approximation was applied to each incident ray. Due to the equivalence of the sound source correlation property and its directivity, solutions for the spatial correlation of the field were transformed into the integration of the coherent function generated by a single directional source. As a typical horizontally stratified media, surface noise in a perfect waveguide was investigated. Correlation coefficients given by normal mode and geometric models show satisfactory agreement. Also, the normalized covariance between sound pressure and the vertical component of particle velocity is proportional to acoustic absorption coefficient, while that of the surface noise in semi-infinitely homogeneous space is zero.展开更多
An inhomogeneously broadened two-mode laser system with cross-correlations between the real and imag- inary parts of quantum noise is considered. The Fokker-Planek equation of the system is derived by the phase-lockin...An inhomogeneously broadened two-mode laser system with cross-correlations between the real and imag- inary parts of quantum noise is considered. The Fokker-Planek equation of the system is derived by the phase-locking method. The steady-state probability distribution, the mean light intensity, the normalization autocorrelation function, and cross correlation function are calculated. The results indicate that： （i） The cross-correlation between the real and imaginary parts of quantum noise can cause the stationary probability distribution from one peak structure to two extrema structure when the laser system is operated above threshold; （ii） The cross-correlation between the real and imaginary parts of quantum noise enhance the light intensity fluctuation and decrease the laser output when the laser system is operated below or near threshold; （iii） The effect of the cross-correlation between the real and imaginary parts of quantum noise is very weak on the stationary properties when the laser system is operated far above threshold.展开更多
Nanopore is an ultra-sensitive electrochemical technique for single molecular detection in confined space. To suppress the noise in detection of the weak current of nanopore, we investigated the influence of membrane ...Nanopore is an ultra-sensitive electrochemical technique for single molecular detection in confined space. To suppress the noise in detection of the weak current of nanopore, we investigated the influence of membrane capacitance and applied voltage on the noise of the current signal by model analysis, simulation and experiment. The obtained results demonstrated that membrane capacitance affects the noise by amplifying the noise of the applied voltage. Therefore, suppression of applied voltage noise is an efficient approach for reducing the noise in nanopore detection. Here, we developed an ultra-low noise instrument system for detecting the single molecule signal in nanopores. As demonstrated by nanopore experiments, the p-p noise of the developed system during the recording is reduced to 3.2B pA using the filter of 5 kHz. Therefore, the developed system could be applied in highly sensitive nanopore detection.展开更多
The conversion efficiency and noise figure (NF) of the silicon-on-insulator (SOI) waveguide-based wavelength converter are investigated with the coupled equations. The effects of the pump power, the nonlinear absorpti...The conversion efficiency and noise figure (NF) of the silicon-on-insulator (SOI) waveguide-based wavelength converter are investigated with the coupled equations. The effects of the pump power, the nonlinear absorption and the waveguide length on the conversion efficiency and noise figure are discussed. The conversion efficiency decreases with the increasing pump power and the noise figure is degraded due to the two-photon absorption (TPA) and the TPA-induced free-carrier absorption (FCA) at the higher pump power. With the increasing of the free carrier lifetime, the conversion efficiency will decrease and the noise figure will increase accordingly. The optimal waveguide length depends on the pump power and the free carrier lifetime. In practical applications, the high conversion efficiency and low noise figure can be achieved by choosing suitable parameters of the silicon waveguide.展开更多
Many interacting biomolecular components in cells form different positive or negative feedback loops. When biological signals transduce through cascades consisting of various loops they will be affected or even distor...Many interacting biomolecular components in cells form different positive or negative feedback loops. When biological signals transduce through cascades consisting of various loops they will be affected or even distorted. Especially, how to process various signals buried in various intrinsic and extrinsic noises is an important issue. This paper analyzes how the response time influences noise filtering ability and how to enhance the ability by coupling different feedback loops. A parameter to measure the response time of the signal transduction, i.e., τ0.9, and its relationship between the response time and noise filtering will be discussed. The authors show clearly that the longer the response time is, the better the ability to filter noises will be. Therefore, to enhance the ability to filter noises, the authors can prolong the response time by coupling different positive or negative feedback loops. The results provide a possible approach to enhance the ability to filter noises in larger biomolecular networks.展开更多
基金The project supported by National Natural Science Foundation of China under Grant No. 10304022, the Science-Technology Fund of Anhui Province for 0utstanding Youth under Grant No. 06042087, the General Fund of the Educational Committee of Anhui Province under Grant No. 2006KJ260B, and the Key Fund of the Ministry of Education of China under Grant No. 206063. We are very grateful to Prof. ZHANG Zhan-Jun for his detailed instructions and help.
文摘We present a robust （n, n）-threshold scheme for multiparty quantum secret sharing of key over two collectivenoise channels （i.e., the collective dephasing channel and the collective rotating channel） via three-photon mixed states, In our scheme, only if all the sharers collaborate together can they establish a joint key with the message sender and extract the secret message from the sender＇s encrypted message. This scheme can be implemented using only a Bell singlet, a one-qubit state and polarization identification of single photon, so it is completely feasible according to the present-day technique.
基金The Advanced Research of Shanghai Technical Committee(No.03DZ05020)
文摘Because of the quantization noise introduced during the compression,super-resolution reconstruction(SRR)techniques are complicated for the compressed images.This paper aims to incorporate the prior knowledge of discrete cosine transform(DCT)coefficients into modeling the quantization noise.The spatial covariance matrix of the quantization noise is estimated by utilizing the Laplacian distribution of the alternating current(AC)coefficients.After estimating the spatial joint covariance of overall noises for the imaging system,we propose a general Bayesian framework to enhance the resolution for compressed images.Experiments demonstrate the effectiveness of the proposed algorithm and show the superiority to previous methods in objective and subjective aspects.
基金This work was supported by the National Natural Science Foundation of China （No.20973119 and No.21033008）.
文摘A two-dimensional generalized Langevin equation is proposed to describe the protein conformational change, compatible to the electron transfer process governed by atomic packing density model. We assume a fractional Gaussian noise and a white noise through bond and through space coordinates respectively, and introduce the coupling effect coming from both fluctuations and equilibrium variances. The general expressions for autocorrelation functions of distance fluctuation and fluorescence lifetime variation are derived, based on which the exact conformational change dynamics can be evaluated with the aid of numerical Laplace inversion technique. We explicitly elaborate the short time and long time approximations. The relationship between the two-diraensional description and the one-dimensional theory is also discussed.
基金Supported by the National Natural Science Foundation of China under Grant No.（50909028）.
文摘Spatial correlation of sound pressure and particle velocity of the surface noise in horizontally stratified media was demonstrated, with directional noise sources uniformly distributed on the ocean surface. In the evaluation of particle velocity, plane wave approximation was applied to each incident ray. Due to the equivalence of the sound source correlation property and its directivity, solutions for the spatial correlation of the field were transformed into the integration of the coherent function generated by a single directional source. As a typical horizontally stratified media, surface noise in a perfect waveguide was investigated. Correlation coefficients given by normal mode and geometric models show satisfactory agreement. Also, the normalized covariance between sound pressure and the vertical component of particle velocity is proportional to acoustic absorption coefficient, while that of the surface noise in semi-infinitely homogeneous space is zero.
基金Supported by the National Natural Science Foundation of China under Grant No.10865006
文摘An inhomogeneously broadened two-mode laser system with cross-correlations between the real and imag- inary parts of quantum noise is considered. The Fokker-Planek equation of the system is derived by the phase-locking method. The steady-state probability distribution, the mean light intensity, the normalization autocorrelation function, and cross correlation function are calculated. The results indicate that： （i） The cross-correlation between the real and imaginary parts of quantum noise can cause the stationary probability distribution from one peak structure to two extrema structure when the laser system is operated above threshold; （ii） The cross-correlation between the real and imaginary parts of quantum noise enhance the light intensity fluctuation and decrease the laser output when the laser system is operated below or near threshold; （iii） The effect of the cross-correlation between the real and imaginary parts of quantum noise is very weak on the stationary properties when the laser system is operated far above threshold.
基金supported by the National Natural Science Foundation of China (21327807, 21421004)Innovation Program of Shanghai Municipal Education Commission (2017-01-07-00-02E00023)the Fundamental Research Funds for the Central Universities (222201718001, 222201717003)
文摘Nanopore is an ultra-sensitive electrochemical technique for single molecular detection in confined space. To suppress the noise in detection of the weak current of nanopore, we investigated the influence of membrane capacitance and applied voltage on the noise of the current signal by model analysis, simulation and experiment. The obtained results demonstrated that membrane capacitance affects the noise by amplifying the noise of the applied voltage. Therefore, suppression of applied voltage noise is an efficient approach for reducing the noise in nanopore detection. Here, we developed an ultra-low noise instrument system for detecting the single molecule signal in nanopores. As demonstrated by nanopore experiments, the p-p noise of the developed system during the recording is reduced to 3.2B pA using the filter of 5 kHz. Therefore, the developed system could be applied in highly sensitive nanopore detection.
基金supported by the Major State Basic Research Development Program of China (No.2010CB328304)the National Natural Science Foundation of China (No.60807022)the Discipline Co-construction Project of Beijing Munnicipal Commission of Education (No.YB20081001301)
文摘The conversion efficiency and noise figure (NF) of the silicon-on-insulator (SOI) waveguide-based wavelength converter are investigated with the coupled equations. The effects of the pump power, the nonlinear absorption and the waveguide length on the conversion efficiency and noise figure are discussed. The conversion efficiency decreases with the increasing pump power and the noise figure is degraded due to the two-photon absorption (TPA) and the TPA-induced free-carrier absorption (FCA) at the higher pump power. With the increasing of the free carrier lifetime, the conversion efficiency will decrease and the noise figure will increase accordingly. The optimal waveguide length depends on the pump power and the free carrier lifetime. In practical applications, the high conversion efficiency and low noise figure can be achieved by choosing suitable parameters of the silicon waveguide.
基金This research is supported by the National Natural Science Foundation of China under Grant No. 10832006, Youth Research under Grant No. 10701052, and Shanghai Pujiang Program.
文摘Many interacting biomolecular components in cells form different positive or negative feedback loops. When biological signals transduce through cascades consisting of various loops they will be affected or even distorted. Especially, how to process various signals buried in various intrinsic and extrinsic noises is an important issue. This paper analyzes how the response time influences noise filtering ability and how to enhance the ability by coupling different feedback loops. A parameter to measure the response time of the signal transduction, i.e., τ0.9, and its relationship between the response time and noise filtering will be discussed. The authors show clearly that the longer the response time is, the better the ability to filter noises will be. Therefore, to enhance the ability to filter noises, the authors can prolong the response time by coupling different positive or negative feedback loops. The results provide a possible approach to enhance the ability to filter noises in larger biomolecular networks.
