Spectral relative dispersion of different hydrometeors is vital to accurately describe sedimentation.Here,the Weather Research and Forecasting model with spectral bin microphysics is used to simulate convective clouds...Spectral relative dispersion of different hydrometeors is vital to accurately describe sedimentation.Here,the Weather Research and Forecasting model with spectral bin microphysics is used to simulate convective clouds in Shouxian of Anhui province in China to study the spectral relative dispersion of different hydrometeors.Firstly,regardless of clean or polluted conditions,the relative dispersion of ice crystal spectra and its volume-mean diameter are negatively correlated,while the relative dispersion of other hydrometeor spectra is positively related to their respective volume-mean diameter.The correlations for cloud droplets and raindrops are affected by the process of collision-coalescence;the correlations for ice crystals,graupel particles,and snow particles could be affected by the deposition,riming,and aggregation processes,respectively.Secondly,relative dispersion parameterizations are developed based on a comprehensive consideration of the relationships between the relative dispersion and volume-mean diameter under both polluted and clean conditions.Finally,the relative dispersion parameterizations are applied to terminal velocity parameterizations.The results show that for cloud droplets,ice crystals,graupel particles,and snow particles,assuming the shape parameter in the Gamma distribution is equal to 0 underestimates the shape parameter and overestimates the relative dispersion;and for raindrops,assuming the shape parameter is equal to 0 is close to the relative dispersion parameterizations.The most appropriate constant shape parameters are recommended for different hydrometeors.The relative dispersion parameterizations developed here shed new light for further optimizing the terminal velocity parameterizations in models.展开更多
In this paper, an improved PI （proportional integral） stator resistance estimation for a DTC （direct torque controlled） induction motor is proposed. This estimation method is based on an on-line stator resistance ...In this paper, an improved PI （proportional integral） stator resistance estimation for a DTC （direct torque controlled） induction motor is proposed. This estimation method is based on an on-line stator resistance correction regarding the variations of the stator current estimation error. In fact, the input variable of the P1 estimator is the stator current estimation error. The main idea is to tune accurately the stator resistance value relatively to the evolution of the stator current estimation error gradient to avoid the drive instability and ensure the tracking of the actual value of the stator resistance. But there is an unavoidable steady state error between the filtered stator current modulus and its estimated value from the dq model of the machine which is due to pseudo random commutations of the inverter switches. This may deteriorate the performance of the proposed fuzzy stator resistance estimator. An offset has been introduced in order to overcome this problem, for different speed command values and load torques. Simulation results show that the proposed estimator was able to successfully track the actual value of the stator resistance lbr different operating conditions.展开更多
Intuitionistic fuzzy sets are generalized fuzzy sets which were first introduced by Atanassov in 1986. In this paper, we introduce the concept of intuitionistic fuzzy M-subsemigroups of an M-semigroup M with respect t...Intuitionistic fuzzy sets are generalized fuzzy sets which were first introduced by Atanassov in 1986. In this paper, we introduce the concept of intuitionistic fuzzy M-subsemigroups of an M-semigroup M with respect to an s-norm S and a t-norm T on in-tuitionistic fuzzy sets and study their properties. In particular, intuitionistic （S,T）-direct products of M-semigroups are considered and some recent results of fuzzy M-subsemigroups of M-semigroups obtained by Zhan and Tan^[21] are extended and generalized to intuitionistic （S, T）-fuzzy M-subsemigroups over M-semigroups.展开更多
Soil saturated hydraulic conductivity(K_s) is a predominant input factor when forecasting the vertical transport of contaminants through the soil or when estimating the flood retention capacity of the soil. Displaceme...Soil saturated hydraulic conductivity(K_s) is a predominant input factor when forecasting the vertical transport of contaminants through the soil or when estimating the flood retention capacity of the soil. Displacement of contaminants in the soil over extended periods of time can be attributed mainly to matrix flow, whereas flow through macropores becomes significant under untypically wet conditions, e.g., during spills or rain storms. To obtain matrix conductivities for a soil, the effects of macropores should be excluded.However, the K_s values of a soil profile are unlikely to be reflected solely by pedotransfer tables based on soil texture and bulk density.In this study, we examined five different methods(pedotransfer table, soil core, borehole permeameter, particle-size distribution curve, and instantaneous profile) to determine K_s values for a mercury-contaminated riparian soil for subsequent simulation of longterm mercury displacement toward groundwater. We found that the determined K_s values increased in the following order: borehole permeameter < particle-size distribution curve < pedotransfer table < instantaneous profile < soil core. The instantaneous profile method yielded K_s values of matrix flow, which additionally reflected the structure-related features of K_s values as provided by the soil core method. Despite being labor intensive and requiring expensive field sensors, the instantaneous profile method may provide the best representative in-situ K_s values for the studied site.展开更多
In this paper,we first propose a hidden rule among the secure message,the initial tensor product of two Bell states and the final tensor product when respectively applying local unitary transformations to the first pa...In this paper,we first propose a hidden rule among the secure message,the initial tensor product of two Bell states and the final tensor product when respectively applying local unitary transformations to the first particle of the two initial Bell states,and then present a high-efficiency quantum steganography protocol under the control of the hidden rule.In the proposed quantum steganography scheme,a hidden channel is established to transfer a secret message within any quantum secure direct communication(QSDC) scheme that is based on 2-level quantum states and unitary transformations.The secret message hiding/unhiding process is linked with the QSDC process only by unitary transformations.To accurately describe the capacity of a steganography scheme,a quantitative measure,named embedding efficiency,is introduced in this paper.The performance analysis shows that the proposed steganography scheme achieves a high efficiency as well as a good imperceptibility.Moreover,it is shown that this scheme can resist all serious attacks including the intercept-resend attack,measurement-resend attack,auxiliary particle attack and even the Denial of Service attack.To improve the efficiency of the proposed scheme,the hidden rule is extended based on the tensor product of multiple Bell states.展开更多
The vertical structure of neutrino-dominated accretion flows （NDAFs） in spherical coordinates is revisited. We define the ratio of the neutrino cooling rate to the viscous heating rate per unit volume, f=-qJqvis. Th...The vertical structure of neutrino-dominated accretion flows （NDAFs） in spherical coordinates is revisited. We define the ratio of the neutrino cooling rate to the viscous heating rate per unit volume, f=-qJqvis. The ignition region is presented when f〉0.5. The solutions show that NDAF is significantly thick. The ignition region is determined by the mass accretion rate and the vis- cosity parameter, which can be considered as the neutrino radiation-dominated region.展开更多
基金supported by the National Natural Science Foundation of China[Grant Nos.41822504,41775131,42027804,42075073,41975181,and 41775136].
文摘Spectral relative dispersion of different hydrometeors is vital to accurately describe sedimentation.Here,the Weather Research and Forecasting model with spectral bin microphysics is used to simulate convective clouds in Shouxian of Anhui province in China to study the spectral relative dispersion of different hydrometeors.Firstly,regardless of clean or polluted conditions,the relative dispersion of ice crystal spectra and its volume-mean diameter are negatively correlated,while the relative dispersion of other hydrometeor spectra is positively related to their respective volume-mean diameter.The correlations for cloud droplets and raindrops are affected by the process of collision-coalescence;the correlations for ice crystals,graupel particles,and snow particles could be affected by the deposition,riming,and aggregation processes,respectively.Secondly,relative dispersion parameterizations are developed based on a comprehensive consideration of the relationships between the relative dispersion and volume-mean diameter under both polluted and clean conditions.Finally,the relative dispersion parameterizations are applied to terminal velocity parameterizations.The results show that for cloud droplets,ice crystals,graupel particles,and snow particles,assuming the shape parameter in the Gamma distribution is equal to 0 underestimates the shape parameter and overestimates the relative dispersion;and for raindrops,assuming the shape parameter is equal to 0 is close to the relative dispersion parameterizations.The most appropriate constant shape parameters are recommended for different hydrometeors.The relative dispersion parameterizations developed here shed new light for further optimizing the terminal velocity parameterizations in models.
文摘In this paper, an improved PI （proportional integral） stator resistance estimation for a DTC （direct torque controlled） induction motor is proposed. This estimation method is based on an on-line stator resistance correction regarding the variations of the stator current estimation error. In fact, the input variable of the P1 estimator is the stator current estimation error. The main idea is to tune accurately the stator resistance value relatively to the evolution of the stator current estimation error gradient to avoid the drive instability and ensure the tracking of the actual value of the stator resistance. But there is an unavoidable steady state error between the filtered stator current modulus and its estimated value from the dq model of the machine which is due to pseudo random commutations of the inverter switches. This may deteriorate the performance of the proposed fuzzy stator resistance estimator. An offset has been introduced in order to overcome this problem, for different speed command values and load torques. Simulation results show that the proposed estimator was able to successfully track the actual value of the stator resistance lbr different operating conditions.
基金the National Natural Science Foundation of China(60474022)the Key Science Foundation of Education Committee of Hubei Province(2004Z002D200529001).
文摘Intuitionistic fuzzy sets are generalized fuzzy sets which were first introduced by Atanassov in 1986. In this paper, we introduce the concept of intuitionistic fuzzy M-subsemigroups of an M-semigroup M with respect to an s-norm S and a t-norm T on in-tuitionistic fuzzy sets and study their properties. In particular, intuitionistic （S,T）-direct products of M-semigroups are considered and some recent results of fuzzy M-subsemigroups of M-semigroups obtained by Zhan and Tan^[21] are extended and generalized to intuitionistic （S, T）-fuzzy M-subsemigroups over M-semigroups.
文摘Soil saturated hydraulic conductivity(K_s) is a predominant input factor when forecasting the vertical transport of contaminants through the soil or when estimating the flood retention capacity of the soil. Displacement of contaminants in the soil over extended periods of time can be attributed mainly to matrix flow, whereas flow through macropores becomes significant under untypically wet conditions, e.g., during spills or rain storms. To obtain matrix conductivities for a soil, the effects of macropores should be excluded.However, the K_s values of a soil profile are unlikely to be reflected solely by pedotransfer tables based on soil texture and bulk density.In this study, we examined five different methods(pedotransfer table, soil core, borehole permeameter, particle-size distribution curve, and instantaneous profile) to determine K_s values for a mercury-contaminated riparian soil for subsequent simulation of longterm mercury displacement toward groundwater. We found that the determined K_s values increased in the following order: borehole permeameter < particle-size distribution curve < pedotransfer table < instantaneous profile < soil core. The instantaneous profile method yielded K_s values of matrix flow, which additionally reflected the structure-related features of K_s values as provided by the soil core method. Despite being labor intensive and requiring expensive field sensors, the instantaneous profile method may provide the best representative in-situ K_s values for the studied site.
基金supported by the National Natural Science Foundation of China (Grant Nos.61170272,61272514,61003287 and 61070163)the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No.20100005120002)+3 种基金the Fok Ying Tong Education Foundation (Grant No.131067)the Shandong Provincial Natural Science Foundation,China (Grant Nos.ZR2011FM023 and ZR2009GM036)the Shandong Province Outstanding Research Award Fund for Young Scientists of China (Grant No.BS2011DX034)the Fundamental Research Funds for the Central Universities (Grant No.BUPT2012RC0221)
文摘In this paper,we first propose a hidden rule among the secure message,the initial tensor product of two Bell states and the final tensor product when respectively applying local unitary transformations to the first particle of the two initial Bell states,and then present a high-efficiency quantum steganography protocol under the control of the hidden rule.In the proposed quantum steganography scheme,a hidden channel is established to transfer a secret message within any quantum secure direct communication(QSDC) scheme that is based on 2-level quantum states and unitary transformations.The secret message hiding/unhiding process is linked with the QSDC process only by unitary transformations.To accurately describe the capacity of a steganography scheme,a quantitative measure,named embedding efficiency,is introduced in this paper.The performance analysis shows that the proposed steganography scheme achieves a high efficiency as well as a good imperceptibility.Moreover,it is shown that this scheme can resist all serious attacks including the intercept-resend attack,measurement-resend attack,auxiliary particle attack and even the Denial of Service attack.To improve the efficiency of the proposed scheme,the hidden rule is extended based on the tensor product of multiple Bell states.
基金supported by the National Basic Research Program of China (Grant No.2009CB824800)the National Natural Science Foundation of China (Grant Nos.10833002,11003016,11073015 and 11103015)the Natural Science Foundation of Fujian Province of China (Grant No.2010J01017)
文摘The vertical structure of neutrino-dominated accretion flows （NDAFs） in spherical coordinates is revisited. We define the ratio of the neutrino cooling rate to the viscous heating rate per unit volume, f=-qJqvis. The ignition region is presented when f〉0.5. The solutions show that NDAF is significantly thick. The ignition region is determined by the mass accretion rate and the vis- cosity parameter, which can be considered as the neutrino radiation-dominated region.
