We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)proc...We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.展开更多
For the first time,the linear and nonlinear vibrations of composite rectangular sandwich plates with various geometric patterns of lattice core have been analytically examined in this work.The plate comprises a lattic...For the first time,the linear and nonlinear vibrations of composite rectangular sandwich plates with various geometric patterns of lattice core have been analytically examined in this work.The plate comprises a lattice core located in the middle and several homogeneous orthotropic layers that are symmetrical relative to it.For this purpose,the partial differential equations of motion have been derived based on the first-order shear deformation theory,employing Hamilton’s principle and Von Kármán’s nonlinear displacement-strain relations.Then,the nonlinear partial differential equations of the plate are converted into a time-dependent nonlinear ordinary differential equation(Duffing equation)by applying the Galerkin method.From the solution of this equation,the natural frequencies are extracted.Then,to calculate the non-linear frequencies of the plate,the non-linear equation of the plate has been solved analytically using the method of multiple scales.Finally,the effect of some critical parameters of the system,such as the thickness,height,and different angles of the stiffeners on the linear and nonlinear frequencies,has been analyzed in detail.To confirmthe solution method,the results of this research have been compared with the reported results in the literature and finite elements in ABAQUS,and a perfect match is observed.The results reveal that the geometry and configuration of core ribs strongly affect the natural frequencies of the plate.展开更多
We introduce a novel scheme for achieving quantum entanglement and Einstein–Podolsky–Rosen(EPR) steering between an atomic ensemble and a mechanical oscillator within a hybrid atom–optomechanical system. The system...We introduce a novel scheme for achieving quantum entanglement and Einstein–Podolsky–Rosen(EPR) steering between an atomic ensemble and a mechanical oscillator within a hybrid atom–optomechanical system. The system comprises an optical cavity, a two-level atomic ensemble and a mechanical resonator that possesses Duffing nonlinearity. The interaction between these components is mediated by the cavity mode, which is driven by an external laser. Our findings indicate that optimizing the coupling strengths between photons and phonons, as well as between atoms and the cavity,leads to maximal entanglement and EPR steering. The amplitude of the driving laser plays a pivotal role in enhancing the coupling between photons and phonons, and the system maintains robust entanglement and EPR steering even under high dissipation, thereby mitigating the constraints on initial conditions and parameter precision. Remarkably, the Duffing nonlinearity enhances the system's resistance to thermal noise, ensuring its stability and entanglement protection. Our analysis of EPR steering conditions reveals that the party with lower dissipation exhibits superior stability and a propensity to steer the party with higher dissipation. These discoveries offer novel perspectives for advancing quantum information processing and communication technologies.展开更多
Satellite images are widely used for remote sensing and defence applications,however,they are subject to a variety of threats.To ensure the security and privacy of these images,theymust be watermarked and encrypted be...Satellite images are widely used for remote sensing and defence applications,however,they are subject to a variety of threats.To ensure the security and privacy of these images,theymust be watermarked and encrypted before communication.Therefore,this paper proposes a novel watermarked satellite image encryption scheme based on chaos,Deoxyribonucleic Acid(DNA)sequence,and hash algorithm.The watermark image,DNA sequence,and plaintext image are passed through the Secure Hash Algorithm(SHA-512)to compute the initial condition(keys)for the Tangent-Delay Ellipse Reflecting Cavity Map(TD-ERCS),Henon,and Duffing chaotic maps,respectively.Through bitwise XOR and substitution,the TD-ERCS map encrypts the watermark image.The ciphered watermark image is embedded in the plaintext image.The embedded plaintext image is permuted row-wise and column-wise using the Henon chaotic map.The permuted image is then bitwise XORed with the values obtained from the Duffing map.For additional security,the XORed image is substituted through a dynamic S-Box.To evaluate the efficiency and performance of the proposed algorithm,several tests are performed which prove its resistance to various types of attacks such as brute-force and statistical attacks.展开更多
为了提高在复杂电磁环境中对电力系统谐波幅值的检测灵敏度,本文以保守型混沌系统为理论基础,提出Van der Pol-Duffing保守型强耦合混沌系统。当检测超弱电力信号时,先对混沌系统进行调试,使其达到混沌相态与大周期相态的临界值,再将待...为了提高在复杂电磁环境中对电力系统谐波幅值的检测灵敏度,本文以保守型混沌系统为理论基础,提出Van der Pol-Duffing保守型强耦合混沌系统。当检测超弱电力信号时,先对混沌系统进行调试,使其达到混沌相态与大周期相态的临界值,再将待检测信号输入混沌系统。当系统处于稳定的大周期相态时,可以获得被检测信号的时域、频谱信息,检测各个谐波分量的幅值。通过仿真试验,对Van der Pol-Duffing保守型强耦合混沌系统与单振子Duffing保守型混沌系统的检测误差和灵敏度进行了比较。结果表明,前者的检测误差为0,灵敏度为10-8,比后者误差更低,灵敏度更高。根据研究内容得出结论 :对Duffing振子和Van der Pol振子进行耦合,能明显提升保守型混沌系统对超弱谐波信号的检测灵敏度,并增强检测方法的抗噪能力。展开更多
基金Project supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission(Grant No.KJQN202400624)the Natural Science Foundation of Chongqing CSTC(Grant No.CSTB2022NSCQBHX0020)+3 种基金the China Electronics Technology Group Corporation 44th Research Institute(Grant No.6310001-2)the Project Grant“Noninvasive Sensing Measurement based on Terahertz Technology”from Province and MOE Collaborative Innovation Centre for New Generation Information Networking and Terminalsthe Key Research Program of CQUPT on Interdisciplinary and Emerging Field(A2018-01)the Venture&Innovation Support program for Chongqing Overseas Returnees Year 2022。
文摘We investigate theoretically the enhancement of mechanical squeezing in a multimode optomechanical system by introducing a coherent phonon–photon interaction via the backward stimulated Brillouin scattering(BSBS)process.The coherent photon–phonon interaction where two optical modes couple to a Brillouin acoustic mode with a large decay rate provides an extra channel for the cooling of a Duffing mechanical oscillator.The squeezing degree and the robustness to the thermal noises of the Duffing mechanical mode can be enhanced greatly.When the Duffing nonlinearity is weak,the squeezing degree of the mechanical mode in the presence of BSBS can be improved by more than one order of magnitude compared with that in the absence of BSBS.Our scheme may be extended to other quantum systems to study novel quantum effects.
文摘For the first time,the linear and nonlinear vibrations of composite rectangular sandwich plates with various geometric patterns of lattice core have been analytically examined in this work.The plate comprises a lattice core located in the middle and several homogeneous orthotropic layers that are symmetrical relative to it.For this purpose,the partial differential equations of motion have been derived based on the first-order shear deformation theory,employing Hamilton’s principle and Von Kármán’s nonlinear displacement-strain relations.Then,the nonlinear partial differential equations of the plate are converted into a time-dependent nonlinear ordinary differential equation(Duffing equation)by applying the Galerkin method.From the solution of this equation,the natural frequencies are extracted.Then,to calculate the non-linear frequencies of the plate,the non-linear equation of the plate has been solved analytically using the method of multiple scales.Finally,the effect of some critical parameters of the system,such as the thickness,height,and different angles of the stiffeners on the linear and nonlinear frequencies,has been analyzed in detail.To confirmthe solution method,the results of this research have been compared with the reported results in the literature and finite elements in ABAQUS,and a perfect match is observed.The results reveal that the geometry and configuration of core ribs strongly affect the natural frequencies of the plate.
基金Project supported by the National Natural Science Foundation of China (Grant No. 12204440)Fundamental Research Program of Shanxi Province (Grant Nos. 20210302123063 and 202103021223184)。
文摘We introduce a novel scheme for achieving quantum entanglement and Einstein–Podolsky–Rosen(EPR) steering between an atomic ensemble and a mechanical oscillator within a hybrid atom–optomechanical system. The system comprises an optical cavity, a two-level atomic ensemble and a mechanical resonator that possesses Duffing nonlinearity. The interaction between these components is mediated by the cavity mode, which is driven by an external laser. Our findings indicate that optimizing the coupling strengths between photons and phonons, as well as between atoms and the cavity,leads to maximal entanglement and EPR steering. The amplitude of the driving laser plays a pivotal role in enhancing the coupling between photons and phonons, and the system maintains robust entanglement and EPR steering even under high dissipation, thereby mitigating the constraints on initial conditions and parameter precision. Remarkably, the Duffing nonlinearity enhances the system's resistance to thermal noise, ensuring its stability and entanglement protection. Our analysis of EPR steering conditions reveals that the party with lower dissipation exhibits superior stability and a propensity to steer the party with higher dissipation. These discoveries offer novel perspectives for advancing quantum information processing and communication technologies.
基金supported by the Deanship of Scientific Research at King Khalid University for funding this work through the large group research project under grant number RGP2/461/45the Deanship of Scientific Researchat Northern Border University,Arar,Saudi Arabia for funding this research work through the project number NBU-FFR-2025-3030-05.
文摘Satellite images are widely used for remote sensing and defence applications,however,they are subject to a variety of threats.To ensure the security and privacy of these images,theymust be watermarked and encrypted before communication.Therefore,this paper proposes a novel watermarked satellite image encryption scheme based on chaos,Deoxyribonucleic Acid(DNA)sequence,and hash algorithm.The watermark image,DNA sequence,and plaintext image are passed through the Secure Hash Algorithm(SHA-512)to compute the initial condition(keys)for the Tangent-Delay Ellipse Reflecting Cavity Map(TD-ERCS),Henon,and Duffing chaotic maps,respectively.Through bitwise XOR and substitution,the TD-ERCS map encrypts the watermark image.The ciphered watermark image is embedded in the plaintext image.The embedded plaintext image is permuted row-wise and column-wise using the Henon chaotic map.The permuted image is then bitwise XORed with the values obtained from the Duffing map.For additional security,the XORed image is substituted through a dynamic S-Box.To evaluate the efficiency and performance of the proposed algorithm,several tests are performed which prove its resistance to various types of attacks such as brute-force and statistical attacks.
文摘为了提高在复杂电磁环境中对电力系统谐波幅值的检测灵敏度,本文以保守型混沌系统为理论基础,提出Van der Pol-Duffing保守型强耦合混沌系统。当检测超弱电力信号时,先对混沌系统进行调试,使其达到混沌相态与大周期相态的临界值,再将待检测信号输入混沌系统。当系统处于稳定的大周期相态时,可以获得被检测信号的时域、频谱信息,检测各个谐波分量的幅值。通过仿真试验,对Van der Pol-Duffing保守型强耦合混沌系统与单振子Duffing保守型混沌系统的检测误差和灵敏度进行了比较。结果表明,前者的检测误差为0,灵敏度为10-8,比后者误差更低,灵敏度更高。根据研究内容得出结论 :对Duffing振子和Van der Pol振子进行耦合,能明显提升保守型混沌系统对超弱谐波信号的检测灵敏度,并增强检测方法的抗噪能力。
