Research on optical computing has recently attracted significant attention due to the transformative advances in machine learning.Among different approaches,diffractive optical networks composed of spatially-engineere...Research on optical computing has recently attracted significant attention due to the transformative advances in machine learning.Among different approaches,diffractive optical networks composed of spatially-engineered transmissive surfaces have been demonstrated for all-optical statistical inference and performing arbitrary linear transformations using passive,free-space optical layers.Here,we introduce a polarization-multiplexed diffractive processor to all-optically perform multiple,arbitrarily-selected linear transformations through a single diffractive network trained using deep learning.In this framework,an array of pre-selected linear polarizers is positioned between trainable transmissive diffractive materials that are isotropic,and different target linear transformations(complex-valued)are uniquely assigned to different combinations of input/output polarization states.The transmission layers of this polarization-multiplexed diffractive network are trained and optimized via deep learning and error-backpropagation by using thousands of examples of the input/output fields corresponding to each one of the complex-valued linear transformations assigned to diffferent input/output polarization combinations.Our results and analysis reveal that a single diffractive network can successfully approximate and all-optically implement a group of arbitrarily-selected target transformations with a negligible error when the number of trainable diffractive features/neurons(N)approaches N_(p)N_(i)N_(o),where Ni and N_(o) represent the number of pixels at the input and output fields-of-view,respectively,and N_(p) refers to the number of unique linear transformations assigned to different input/output polarization combinations.This polarization-multiplexed all-optical diffractive processor can find various applications in optical computing and polarization-based machine vision tasks.展开更多
An ultra-simple and miniaturized spectrometer using an arbitrarily shaped pinhole as diffraction element reconstructs a broadband spectrum from the information of diffraction of monochromatic radiation by clever compu...An ultra-simple and miniaturized spectrometer using an arbitrarily shaped pinhole as diffraction element reconstructs a broadband spectrum from the information of diffraction of monochromatic radiation by clever computational reconstruction algorithms.This circumvents complex calibration procedures and paves the way to cost-effective on-chip spectrometers combining fast acquisition without significant loss in spectral resolution.展开更多
Containing Lorentz invariance violation(LIV),a new form of the fermions dynamic equation under the background of the curved space-time of the arbitrarily accelerating black hole,is studied.Firstly,we consider the new ...Containing Lorentz invariance violation(LIV),a new form of the fermions dynamic equation under the background of the curved space-time of the arbitrarily accelerating black hole,is studied.Firstly,we consider the new form of the fermions dynamic equation with arbitrary spin containing LIV in curved space-time,and research the fermions dynamic equation with spin-1/2containing LIV.On this basis,according to the semi-classical theory and black hole quantum tunneling radiation theory,the quantum tunneling radiation of the arbitrarily accelerating Kinnersly black hole is modified correctly,and the corrected physical quantities such as black hole temperature and quantum tunneling rate are deeply discussed.The fermions dynamic equation with arbitrary spin in the arbitrarily accelerating black hole space-time and its solution are explained in detail.In order to further obtain the correction effect of the Planck scale,this article considers beyond the semi-classical theory and further obtains new expressions of the black hole temperature and tunneling radiation rate.展开更多
Shape memory effect (SME) of polymers refers to their ability to fix temporary shapes and revert to their permanent shapes in an on demand fashion.Whereas the permanent shape is typically determined by the molding pro...Shape memory effect (SME) of polymers refers to their ability to fix temporary shapes and revert to their permanent shapes in an on demand fashion.Whereas the permanent shape is typically determined by the molding processes,the temporary shape(s) can be arbitrarily defined by an external force applied during the programming step(or shape fixing step).This attribute differentiates shape memory polymers (SMP) from many other classes of stimuli-responsive shape-changing polymers,in terms of both the material behaviors and potential applications.展开更多
The capturability of an arbitrarily maneuvering target featuring speed superiority over an interceptor is analyzed for Augmented Pure Proportional Navigation(APPN)and RetroAugmented Proportional Navigation(RAPN)guidan...The capturability of an arbitrarily maneuvering target featuring speed superiority over an interceptor is analyzed for Augmented Pure Proportional Navigation(APPN)and RetroAugmented Proportional Navigation(RAPN)guidance.This paper focuses on intercepting arbitrary maneuvers to study more general interception problems.A comparative analysis of the capture region between head-on interception related to APPN and head-pursuit interception related to RAPN is proposed.The results indicate that RAPN performs better than APPN in capturability.It is concluded that increasing the target velocity,which increases the velocity ratio,significantly weakens the capturability of the interceptor,and the average acceleration and relative distance affect the location of the capture region but not its size.The analysis is based on prior knowledge of the target maneuver,which inevitably leads to deviations from actual maneuvers in practical engagement,so a deviation analysis is implemented.The effective capture region shrinks as the absolute value of acceleration deviation increases,and the RAPN has a better deviation fault tolerance compared with the APPN.The results reveal that a larger relative distance can weaken the deviation fault tolerance,and the target velocity has opposite effects on head-on and head-pursuit interception.展开更多
The shape of particles has a significant influence on the behavior of suspensions,as the particle-fluid,particle-particle,and particle-wall interactions depend on it.However,the simultaneous consideration of complex p...The shape of particles has a significant influence on the behavior of suspensions,as the particle-fluid,particle-particle,and particle-wall interactions depend on it.However,the simultaneous consideration of complex particle shapes and four-way coupling remains a major challenge.This is mainly due to a lack of suitable contact models.Contact models for complex shapes have been proposed in literature,and most limit the accuracy of the particle-fluid interaction.For this reason,this paper presents a novel contact model for complex convex particle shapes for use with partially saturated methods,in which we propose to obtain necessary contact properties,such as the indentation depth,by a discretization of the contact area.The goal of the proposed model is to enable comprehensive and accurate studies of particulate flows,especially with high volume fractions,that lead to new insights and contribute to the improvement of existing industrial processes.To ensure correctness and sustainability,we validate the model extensively by studying cases with and without fluid.In the latter case,we use the homogenized lattice Boltzmann method.The provided investigations show a great agreement of the proposed discrete contact model with analytical solutions and the literature.展开更多
In this article, a formulation for a hollow cylinder reinforced with an electroelastic layer is investigated. The hollow cylinder and its electro-elastic coating are under the Saint-Venant torsional loading. First, th...In this article, a formulation for a hollow cylinder reinforced with an electroelastic layer is investigated. The hollow cylinder and its electro-elastic coating are under the Saint-Venant torsional loading. First, the solution to the problem containing a Volterra-type screw dislocation is obtained by using the Fourier transform. The problem is then reduced to a set of Cauchy singular integral equations by the distributed dislocation method. Finally, several examples are presented to show the effect of the electro-elastic coating on the reduction of the stress intensity factors at the crack tips.展开更多
Small storage space for photographs in formal documents is increasingly necessary in today＇s needs for huge amounts of data communication and storage. Traditional compression algorithms do not sufficiently utilize th...Small storage space for photographs in formal documents is increasingly necessary in today＇s needs for huge amounts of data communication and storage. Traditional compression algorithms do not sufficiently utilize the distinctness of formal photographs. That is, the object is an image of the human head, and the background is in unicolor. Therefore, the compression is of low efficiency and the image after compression is still space-consuming. This paper presents an image compression algorithm based on object segmentation for practical high-efficiency applications. To achieve high coding efficiency, shape-adaptive discrete wavelet transforms are used to transformation arbitrarily shaped objects. The areas of the human head and its background are compressed separately to reduce the coding redundancy of the background. Two methods, lossless image contour coding based on differential chain, and modified set partitioning in hierarchical trees （SPIHT） algorithm of arbitrary shape, are discussed in detail. The results of experiments show that when bit per pixel （bpp）is equal to 0.078, peak signal-to-noise ratio （PSNR） of reconstructed photograph will exceed the standard of SPIHT by nearly 4dB.展开更多
The effect of correlated fading reduces the performance gain in multi-antenna communications. Diversity combining is a well-known technique to reduce the effect of correlation. But still, it is an open problem to quan...The effect of correlated fading reduces the performance gain in multi-antenna communications. Diversity combining is a well-known technique to reduce the effect of correlation. But still, it is an open problem to quantify as the diversity scheme is more efficient in enhancing the security of cellular multicast network mitigating the effects of correlation. Motivated by this issue, this paper considers a secure wireless multicasting scenario through correlated cellular networks in the presence of multiple eavesdroppers. The selection combining (SC) and switch and stay combining (SSC) techniques are considered in dual arbitrarily correlated Nakagami-m fading channels. The closed-form analytical expressions for the probability of non-zero secrecy multicast capacity and the secure outage probability for multicasting are derived to understand the insight into the effects of correlation on the SC and SSC diversity schemes and to quantify which diversity scheme is more efficient in enhancing the security of correlated multicast networks. The results show that, although the diversity gain reduces the effect of correlation, the diversity gain provided by the SC diversity scheme is more significant in mitigating the effect of correlation compared to the SSC diversity scheme. Due to the selection mechanism of SC diversity, it is more sensitive to the change of SNR of the eavesdropper’s channel compared to the case of the SSC diversity scheme.展开更多
Based on the high order nonlinear and dispersive wave equation with a dissipative term, a numerical model for nonlinear waves is developed, It is suitable to calculate wave propagation in water areas with an arbitrari...Based on the high order nonlinear and dispersive wave equation with a dissipative term, a numerical model for nonlinear waves is developed, It is suitable to calculate wave propagation in water areas with an arbitrarily varying bottom slope and a relative depth h/L(0)less than or equal to1. By the application of the completely implicit stagger grid and central difference algorithm, discrete governing equations are obtained. Although the central difference algorithm of second-order accuracy both in time and space domains is used to yield the difference equations, the order of truncation error in the difference equation is the same as that of the third-order derivatives of the Boussinesq equation. In this paper, the correction to the first-order derivative is made, and the accuracy of the difference equation is improved. The verifications of accuracy show that the results of the numerical model are in good agreement with those of analytical Solutions and physical models.展开更多
Hypothesis testing for arbitrarily varying source (AVS), which is to decide between the two hypotheses for the varying behavior of the distribution of AVS, is considered in this paper. We determine the best asymptotic...Hypothesis testing for arbitrarily varying source (AVS), which is to decide between the two hypotheses for the varying behavior of the distribution of AVS, is considered in this paper. We determine the best asymptotic exponent of the second kind of error probability when the first kind of error probability is fixed. This result generalizes the well-known lemma of Stein in statistics. As a corollary, Strassen’s coding theorem for AVS is obtained.展开更多
Csiszar's strong coding theorem for discrete memoryless scarce is generalized to arbitrarily varying source.We also determine the asymptotic error exponent for arbitrarily wrying source.
Squeezed quantum vacua seems to violate the averaged null energy conditions (ANEC’s), because they have a negative energy density. When treated as a perfect fluid, rapidly rotating Casimir plates will create vorticit...Squeezed quantum vacua seems to violate the averaged null energy conditions (ANEC’s), because they have a negative energy density. When treated as a perfect fluid, rapidly rotating Casimir plates will create vorticity in the vacuum bounded by them. The geometry resulting from an arbitrarily extended Casimir plates along their axis of rotation is similar to van Stockum spacetime. We observe closed timelike curves (CTC’s) forming in the exterior of the system resulting from frame dragging. The exterior geometry of this system is similar to Kerr geometry, but because of violation of ANEC, the Cauchy horizon lies outside the system unlike Kerr blackholes, giving more emphasis on whether spacetime is multiply connected at the microscopic level.展开更多
A simplified equation for the axisymmetry problems of ring shells of elliptical cross section under arbitrarily distributed loads in complex form has been obtained. The equation is equivalent to the exact equations wi...A simplified equation for the axisymmetry problems of ring shells of elliptical cross section under arbitrarily distributed loads in complex form has been obtained. The equation is equivalent to the exact equations within the error range of the thin shell theory, with the singularities at the points of meridional extreme values eliminated. The equivalent integral equations and the numerical solutions are given. Three examples of expansion joints, ring shells under hydro-pressure and sealing ring of semi-elliptical cross section are calculated and compared with the exact solutions and the experimental results.展开更多
When the error probability is less than 2--"", the minimum compression rate(r-optimal rate) of arbitrarily varying source with a fidelity criterion is determined. Thisgeneralizes the result of Arutyunyan and...When the error probability is less than 2--"", the minimum compression rate(r-optimal rate) of arbitrarily varying source with a fidelity criterion is determined. Thisgeneralizes the result of Arutyunyan and Mekaushll] for discrete memoryless source witha fidelity criterion, and is called strong coding theorem of arbitrarily varying source witha fidelity criterion. We also determine the asymptotic error exponellt for arbitrarily varying source with a fidelity criterion. This generalizes Marton’s result in [2] for discretememoryless source with a fidelity criterion.展开更多
Gene expression studies are important for revealing gene functions putatively involved in biological processes. We were interested in identifying differentially expressed genes during leaf development in rice. We comb...Gene expression studies are important for revealing gene functions putatively involved in biological processes. We were interested in identifying differentially expressed genes during leaf development in rice. We combined the RNA arbitrarily primed-polymerase chain reaction （RAP.PCR） and dot blot hybridization methods to screen a rice leaf primordium cDNA library. Three developmental stages during vegetative growth were examined. The cDNA clones showing different hybridization patterns were further analyzed and verified. Here we demonstrate that the combination of RAP-PCR and dot blot hybridization could provide an efficient and relatively low-cost cDNA library screening approach to discover genes not previously known to be associated with leaf development in rice, We believe that the findings described here will help to elucidate the molecular mechanism（s） underlying the developmental processes of rice leaf展开更多
For reliability analysis the Boolean variable, which is discrete, is used to represent the failure or success of a system or a component. And the calculation of occurrence probability of 0/1 event, which is continous ...For reliability analysis the Boolean variable, which is discrete, is used to represent the failure or success of a system or a component. And the calculation of occurrence probability of 0/1 event, which is continous real variable in [0, 1], is required. The system failure (success) probability may be derived from those of components. In展开更多
An approximation approach is proposed for realizing an arbitrarily shaped acoustic cloak.Based on the effective medium theory,the designed cloak is a discrete layered structure using homogeneous isotropic materials.Th...An approximation approach is proposed for realizing an arbitrarily shaped acoustic cloak.Based on the effective medium theory,the designed cloak is a discrete layered structure using homogeneous isotropic materials.The performance of the cloak is simulated,and the results demonstrate that the cloak possesses properties of low-reflection outside the cloak and wavefront-bending in the cloak shell.This work proves the feasibility of realizing an arbitrarily shaped acoustic cloak using normal materials.展开更多
文摘Research on optical computing has recently attracted significant attention due to the transformative advances in machine learning.Among different approaches,diffractive optical networks composed of spatially-engineered transmissive surfaces have been demonstrated for all-optical statistical inference and performing arbitrary linear transformations using passive,free-space optical layers.Here,we introduce a polarization-multiplexed diffractive processor to all-optically perform multiple,arbitrarily-selected linear transformations through a single diffractive network trained using deep learning.In this framework,an array of pre-selected linear polarizers is positioned between trainable transmissive diffractive materials that are isotropic,and different target linear transformations(complex-valued)are uniquely assigned to different combinations of input/output polarization states.The transmission layers of this polarization-multiplexed diffractive network are trained and optimized via deep learning and error-backpropagation by using thousands of examples of the input/output fields corresponding to each one of the complex-valued linear transformations assigned to diffferent input/output polarization combinations.Our results and analysis reveal that a single diffractive network can successfully approximate and all-optically implement a group of arbitrarily-selected target transformations with a negligible error when the number of trainable diffractive features/neurons(N)approaches N_(p)N_(i)N_(o),where Ni and N_(o) represent the number of pixels at the input and output fields-of-view,respectively,and N_(p) refers to the number of unique linear transformations assigned to different input/output polarization combinations.This polarization-multiplexed all-optical diffractive processor can find various applications in optical computing and polarization-based machine vision tasks.
文摘An ultra-simple and miniaturized spectrometer using an arbitrarily shaped pinhole as diffraction element reconstructs a broadband spectrum from the information of diffraction of monochromatic radiation by clever computational reconstruction algorithms.This circumvents complex calibration procedures and paves the way to cost-effective on-chip spectrometers combining fast acquisition without significant loss in spectral resolution.
基金Supported by the National Natural Science Foundation of China under Grant No.U2031121.
文摘Containing Lorentz invariance violation(LIV),a new form of the fermions dynamic equation under the background of the curved space-time of the arbitrarily accelerating black hole,is studied.Firstly,we consider the new form of the fermions dynamic equation with arbitrary spin containing LIV in curved space-time,and research the fermions dynamic equation with spin-1/2containing LIV.On this basis,according to the semi-classical theory and black hole quantum tunneling radiation theory,the quantum tunneling radiation of the arbitrarily accelerating Kinnersly black hole is modified correctly,and the corrected physical quantities such as black hole temperature and quantum tunneling rate are deeply discussed.The fermions dynamic equation with arbitrary spin in the arbitrarily accelerating black hole space-time and its solution are explained in detail.In order to further obtain the correction effect of the Planck scale,this article considers beyond the semi-classical theory and further obtains new expressions of the black hole temperature and tunneling radiation rate.
文摘Shape memory effect (SME) of polymers refers to their ability to fix temporary shapes and revert to their permanent shapes in an on demand fashion.Whereas the permanent shape is typically determined by the molding processes,the temporary shape(s) can be arbitrarily defined by an external force applied during the programming step(or shape fixing step).This attribute differentiates shape memory polymers (SMP) from many other classes of stimuli-responsive shape-changing polymers,in terms of both the material behaviors and potential applications.
基金the National Natural Science Foundation of China(No.62073335)the Science Fund for Distinguished Young People in Shaanxi Province,China(No.2022JC-42)the China Postdoctoral Science Foundation(Nos.2017M613201,2019T120944 and 2020M683737).
文摘The capturability of an arbitrarily maneuvering target featuring speed superiority over an interceptor is analyzed for Augmented Pure Proportional Navigation(APPN)and RetroAugmented Proportional Navigation(RAPN)guidance.This paper focuses on intercepting arbitrary maneuvers to study more general interception problems.A comparative analysis of the capture region between head-on interception related to APPN and head-pursuit interception related to RAPN is proposed.The results indicate that RAPN performs better than APPN in capturability.It is concluded that increasing the target velocity,which increases the velocity ratio,significantly weakens the capturability of the interceptor,and the average acceleration and relative distance affect the location of the capture region but not its size.The analysis is based on prior knowledge of the target maneuver,which inevitably leads to deviations from actual maneuvers in practical engagement,so a deviation analysis is implemented.The effective capture region shrinks as the absolute value of acceleration deviation increases,and the RAPN has a better deviation fault tolerance compared with the APPN.The results reveal that a larger relative distance can weaken the deviation fault tolerance,and the target velocity has opposite effects on head-on and head-pursuit interception.
基金The research leading to these results was conducted during the IGF Project AiF 21096 N of the FEI that has been supported via AiF within the programme for promoting the Industrial Collective Research(IGF)of the Federal Ministry of Economic Affairs and Climate Action(BMWK)based on a resolution of the German Parliament.
文摘The shape of particles has a significant influence on the behavior of suspensions,as the particle-fluid,particle-particle,and particle-wall interactions depend on it.However,the simultaneous consideration of complex particle shapes and four-way coupling remains a major challenge.This is mainly due to a lack of suitable contact models.Contact models for complex shapes have been proposed in literature,and most limit the accuracy of the particle-fluid interaction.For this reason,this paper presents a novel contact model for complex convex particle shapes for use with partially saturated methods,in which we propose to obtain necessary contact properties,such as the indentation depth,by a discretization of the contact area.The goal of the proposed model is to enable comprehensive and accurate studies of particulate flows,especially with high volume fractions,that lead to new insights and contribute to the improvement of existing industrial processes.To ensure correctness and sustainability,we validate the model extensively by studying cases with and without fluid.In the latter case,we use the homogenized lattice Boltzmann method.The provided investigations show a great agreement of the proposed discrete contact model with analytical solutions and the literature.
文摘In this article, a formulation for a hollow cylinder reinforced with an electroelastic layer is investigated. The hollow cylinder and its electro-elastic coating are under the Saint-Venant torsional loading. First, the solution to the problem containing a Volterra-type screw dislocation is obtained by using the Fourier transform. The problem is then reduced to a set of Cauchy singular integral equations by the distributed dislocation method. Finally, several examples are presented to show the effect of the electro-elastic coating on the reduction of the stress intensity factors at the crack tips.
基金This work was supported by National Natural Science Foundation of China (No.60372066)
文摘Small storage space for photographs in formal documents is increasingly necessary in today＇s needs for huge amounts of data communication and storage. Traditional compression algorithms do not sufficiently utilize the distinctness of formal photographs. That is, the object is an image of the human head, and the background is in unicolor. Therefore, the compression is of low efficiency and the image after compression is still space-consuming. This paper presents an image compression algorithm based on object segmentation for practical high-efficiency applications. To achieve high coding efficiency, shape-adaptive discrete wavelet transforms are used to transformation arbitrarily shaped objects. The areas of the human head and its background are compressed separately to reduce the coding redundancy of the background. Two methods, lossless image contour coding based on differential chain, and modified set partitioning in hierarchical trees （SPIHT） algorithm of arbitrary shape, are discussed in detail. The results of experiments show that when bit per pixel （bpp）is equal to 0.078, peak signal-to-noise ratio （PSNR） of reconstructed photograph will exceed the standard of SPIHT by nearly 4dB.
文摘The effect of correlated fading reduces the performance gain in multi-antenna communications. Diversity combining is a well-known technique to reduce the effect of correlation. But still, it is an open problem to quantify as the diversity scheme is more efficient in enhancing the security of cellular multicast network mitigating the effects of correlation. Motivated by this issue, this paper considers a secure wireless multicasting scenario through correlated cellular networks in the presence of multiple eavesdroppers. The selection combining (SC) and switch and stay combining (SSC) techniques are considered in dual arbitrarily correlated Nakagami-m fading channels. The closed-form analytical expressions for the probability of non-zero secrecy multicast capacity and the secure outage probability for multicasting are derived to understand the insight into the effects of correlation on the SC and SSC diversity schemes and to quantify which diversity scheme is more efficient in enhancing the security of correlated multicast networks. The results show that, although the diversity gain reduces the effect of correlation, the diversity gain provided by the SC diversity scheme is more significant in mitigating the effect of correlation compared to the SSC diversity scheme. Due to the selection mechanism of SC diversity, it is more sensitive to the change of SNR of the eavesdropper’s channel compared to the case of the SSC diversity scheme.
基金This research was financially supported by China National Key Basic Research Project "Circulation Principal and Mathematic Model" (Grant No. 1999043810) Guangdong Science and Technology Innovation Project: "Disaster Diagnoses of Sea Walls" (99B07102G)
文摘Based on the high order nonlinear and dispersive wave equation with a dissipative term, a numerical model for nonlinear waves is developed, It is suitable to calculate wave propagation in water areas with an arbitrarily varying bottom slope and a relative depth h/L(0)less than or equal to1. By the application of the completely implicit stagger grid and central difference algorithm, discrete governing equations are obtained. Although the central difference algorithm of second-order accuracy both in time and space domains is used to yield the difference equations, the order of truncation error in the difference equation is the same as that of the third-order derivatives of the Boussinesq equation. In this paper, the correction to the first-order derivative is made, and the accuracy of the difference equation is improved. The verifications of accuracy show that the results of the numerical model are in good agreement with those of analytical Solutions and physical models.
基金Supported by the Young Teacher Foundation of Chinese Educational Ministry and by the National Natural Science Foundation of China.
文摘Hypothesis testing for arbitrarily varying source (AVS), which is to decide between the two hypotheses for the varying behavior of the distribution of AVS, is considered in this paper. We determine the best asymptotic exponent of the second kind of error probability when the first kind of error probability is fixed. This result generalizes the well-known lemma of Stein in statistics. As a corollary, Strassen’s coding theorem for AVS is obtained.
文摘Csiszar's strong coding theorem for discrete memoryless scarce is generalized to arbitrarily varying source.We also determine the asymptotic error exponent for arbitrarily wrying source.
文摘Squeezed quantum vacua seems to violate the averaged null energy conditions (ANEC’s), because they have a negative energy density. When treated as a perfect fluid, rapidly rotating Casimir plates will create vorticity in the vacuum bounded by them. The geometry resulting from an arbitrarily extended Casimir plates along their axis of rotation is similar to van Stockum spacetime. We observe closed timelike curves (CTC’s) forming in the exterior of the system resulting from frame dragging. The exterior geometry of this system is similar to Kerr geometry, but because of violation of ANEC, the Cauchy horizon lies outside the system unlike Kerr blackholes, giving more emphasis on whether spacetime is multiply connected at the microscopic level.
基金Project supported by the National Natural Science Foundation of China.
文摘A simplified equation for the axisymmetry problems of ring shells of elliptical cross section under arbitrarily distributed loads in complex form has been obtained. The equation is equivalent to the exact equations within the error range of the thin shell theory, with the singularities at the points of meridional extreme values eliminated. The equivalent integral equations and the numerical solutions are given. Three examples of expansion joints, ring shells under hydro-pressure and sealing ring of semi-elliptical cross section are calculated and compared with the exact solutions and the experimental results.
文摘When the error probability is less than 2--"", the minimum compression rate(r-optimal rate) of arbitrarily varying source with a fidelity criterion is determined. Thisgeneralizes the result of Arutyunyan and Mekaushll] for discrete memoryless source witha fidelity criterion, and is called strong coding theorem of arbitrarily varying source witha fidelity criterion. We also determine the asymptotic error exponellt for arbitrarily varying source with a fidelity criterion. This generalizes Marton’s result in [2] for discretememoryless source with a fidelity criterion.
基金Supported by the Area of Excellence Grant on Plant and Fungal Biotechnologyfrom the University Grants Committee of the Hong Kong SAR Government
文摘Gene expression studies are important for revealing gene functions putatively involved in biological processes. We were interested in identifying differentially expressed genes during leaf development in rice. We combined the RNA arbitrarily primed-polymerase chain reaction （RAP.PCR） and dot blot hybridization methods to screen a rice leaf primordium cDNA library. Three developmental stages during vegetative growth were examined. The cDNA clones showing different hybridization patterns were further analyzed and verified. Here we demonstrate that the combination of RAP-PCR and dot blot hybridization could provide an efficient and relatively low-cost cDNA library screening approach to discover genes not previously known to be associated with leaf development in rice, We believe that the findings described here will help to elucidate the molecular mechanism（s） underlying the developmental processes of rice leaf
文摘For reliability analysis the Boolean variable, which is discrete, is used to represent the failure or success of a system or a component. And the calculation of occurrence probability of 0/1 event, which is continous real variable in [0, 1], is required. The system failure (success) probability may be derived from those of components. In
文摘An approximation approach is proposed for realizing an arbitrarily shaped acoustic cloak.Based on the effective medium theory,the designed cloak is a discrete layered structure using homogeneous isotropic materials.The performance of the cloak is simulated,and the results demonstrate that the cloak possesses properties of low-reflection outside the cloak and wavefront-bending in the cloak shell.This work proves the feasibility of realizing an arbitrarily shaped acoustic cloak using normal materials.
