The thermal compression deformation behavior of Mg-6Li-11Zn-2.5Y alloy was systematically investigated by using the isothermal hot compression tests using the Gleeble-3500 thermal mechanical physical simulation system...
详细信息
The thermal compression deformation behavior of Mg-6Li-11Zn-2.5Y alloy was systematically investigated by using the isothermal hot compression tests using the Gleeble-3500 thermal mechanical physical simulation system with the conditions of the temperature of 513-593 K and the strain rate of *** constitutive model and thermal processing map were *** variation pattern of the unstable region under different strains was analyzed and the safe processing region was *** influence of different power dissipation values and deformation activation energies on the dynamic recrystallization mechanism was *** results demonstrate that the deformation activation energy is 156.08 k J/*** unstable region gradually expands from the low temperature and low strain region to the high temperature and high strain region with the strain *** the unstable region,adiabatic shear band pear in a-Mg phase,of which the main reason is the poor processing formability in the unstable *** dominant nucleation mechanism is discontinuous dynamic recrystallization under the conditions of high power dissipation and low deformation activation ***,under the conditions of low power dissipation and high deformation activation energy,the nucleation mechanism is mainly driven by the particle stimulated nucleation.
In our current study,the impact of pre-creep treatment at 300 ℃ and 560 MPa for 1000 h on the sub-sequent creep behavior and properties at an elevated temperature of 400 ℃ have been *** characterization of the resul...
详细信息
Constructing an effective common latent embedding by aligning the latent spaces of cross-modal variational autoencoders（VAEs） is a popular strategy for generalized zero-shot learning（GZSL）. However, due to the lac...
详细信息
Constructing an effective common latent embedding by aligning the latent spaces of cross-modal variational autoencoders（VAEs） is a popular strategy for generalized zero-shot learning（GZSL）. However, due to the lack of fine-grained instance-wise annotations, existing VAE methods can easily suffer from the posterior collapse problem. In this paper, we propose an innovative asymmetric VAE network by aligning enhanced feature representation（AEFR） for GZSL. Distinguished from general VAE structures, we designed two asymmetric encoders for visual and semantic observations and one decoder for visual reconstruction. Specifically, we propose a simple yet effective gated attention mechanism（GAM） in the visual encoder for enhancing the information interaction between observations and latent variables, alleviating the possible posterior collapse problem effectively. In addition, we propose a novel distributional decoupling-based contrastive learning（D2-CL） to guide learning classification-relevant information while aligning the representations at the taxonomy level in the latent representation space. Extensive experiments on publicly available datasets demonstrate the state-of-the-art performance of our method. The source code is available at https://***/seeyourmind/AEFR.
The optical potential ambiguity is a long-standing problem in the analysis of elastic scattering *** a specific collid-ing system,ambiguous potential families can lead to different behaviors in the nearside and farsid...
详细信息
The optical potential ambiguity is a long-standing problem in the analysis of elastic scattering *** a specific collid-ing system,ambiguous potential families can lead to different behaviors in the nearside and farside scattering *** contrast,the envelope method can decompose the experimental data into two components with negative and positive deflection angles,***,a question arises as to whether the comparison between the calculated nearside(or farside)component and the derived positive-deflection-angle(or negative-deflection-angle)component can help analyze the potential ambiguity *** this study,we conducted a trial application of the envelope method to the potential ambiguity *** envelope method was improved by including uncertainties in the experimental *** colliding systems of 16O+28Si at 215.2 MeV and 12C+12C at 1016 MeV were considered in the *** each colliding system,the angular distribution experimental data were described nearly equally well by two potential sets,one of which is“surface transpar-ent”and the other is *** calculated angular distributions were decomposed into nearside and farside scattering *** the improved envelope method,the experimental data were decomposed into the positive-deflection-angle and negative-deflection-angle components,which were then compared with the calculated nearside and farside *** capability of the envelope method to analyze the potential ambiguities was also discussed.
Over the past few decades, numerous adaptive Kalman filters(AKFs) have been proposed. However, achieving online estimation with both high estimation accuracy and fast convergence speed is challenging, especially when ...
详细信息
Over the past few decades, numerous adaptive Kalman filters(AKFs) have been proposed. However, achieving online estimation with both high estimation accuracy and fast convergence speed is challenging, especially when both the process noise and measurement noise covariance matrices are relatively inaccurate. Maximum likelihood estimation(MLE) possesses the potential to achieve this goal, since its theoretical accuracy is guaranteed by asymptotic optimality and the convergence speed is fast due to weak dependence on accurate state ***, the maximum likelihood cost function is so intricate that the existing MLE methods can only simply ignore all historical measurement information to achieve online estimation,which cannot adequately realize the potential of MLE. In order to design online MLE-based AKFs with high estimation accuracy and fast convergence speed, an online exploratory MLE approach is proposed, based on which a mini-batch coordinate descent noise covariance matrix estimation framework is developed. In this framework, the maximum likelihood cost function is simplified for online estimation with fewer and simpler terms which are selected in a mini-batch and calculated with a backtracking method. This maximum likelihood cost function is sidestepped and solved by exploring possible estimated noise covariance matrices adaptively while the historical measurement information is adequately utilized. Furthermore, four specific algorithms are derived under this framework to meet different practical requirements in terms of convergence speed, estimation accuracy,and calculation load. Abundant simulations and experiments are carried out to verify the validity and superiority of the proposed algorithms as compared with existing state-of-the-art AKFs.
Enhancing the bonding strength, optimizing the microstructure and refining the properties represent effective strategies for the fabrication of heterogeneous composite plates. In this study, composite plates of Al/Mg/...
详细信息
Enhancing the bonding strength, optimizing the microstructure and refining the properties represent effective strategies for the fabrication of heterogeneous composite plates. In this study, composite plates of Al/Mg/Al were fabricated through hard plate rolling(HPR) with a reduction in rolling ranging from 40 % to 80 %. The research primarily concentrates on the substrate in the influence of rolling dynamic recrystallization(DRX) behavior on the grain morphology evolution and mechanical properties of AZ31 magnesium alloy sheets during the process. The findings indicate that at a compression amount of 60 %, the composite plate exhibits an ultimate tensile strength(UTS), a maximum elongation(EL) of 12.5 %, and improved interface bonding. Comparative analysis reveals the occurrence of DRX on the Mg side, resulting in the formation of small DRXed grains being generated. With an increase in reduction, DRX is facilitated, leading to an initial rise and subsequent decline in the proportion of DRXed grains. The proliferation of fine grains hinder dislocation movement, thereby reinforcing composite ***, an elevation in the degree of recrystallization enhances the initiation of non-basal slip and enhances the plasticity of sheet metal. This study offers valuable scientific guidance and technical assistance for the production of forming high-quality Mg–Al composite plates.
Due to its decentralized and tamper-proof features, blockchain is frequently employed in the financial, traceability, and distributed storage industries. The agreement algorithm, which is a crucial component of the bl...
详细信息
The corona resistance lifespan of insulating materials is a critical factor in determining the service life of wind turbines. To address this issue, this study used aluminum dihydrogen phosphate (ADP) as binder combin...
详细信息
Inspired by basic circuit connection methods,memristors can also be utilized in the construction of complex discrete chaotic *** investigate the dynamical effects of hybrid memristors,we propose two hybrid tri-memrist...
详细信息
Inspired by basic circuit connection methods,memristors can also be utilized in the construction of complex discrete chaotic *** investigate the dynamical effects of hybrid memristors,we propose two hybrid tri-memristor hyperchaotic(HTMH)mapping structures based on the hybrid parallel/cascade and cascade/parallel operations,*** the HTMH mapping structure with hybrid parallel/cascade operation as an example,this map possesses a spatial invariant set whose stability is closely related to the initial states of the *** distributions and bifurcation behaviours dependent on the control parameters are explored with numerical ***,the memristor initial offset-boosting mechanism is theoretically demonstrated,and memristor initial offset-boosting behaviours are numerically *** results clarify that the HTMH map can exhibit hyperchaotic behaviours and extreme multistability with homogeneous coexisting infinite *** addition,an FPGA hardware platform is fabricated to implement the HTMH map and generate pseudorandom numbers(PRNs)with high ***,the generated PRNs can be applied in Wasserstein generative adversarial nets(WGANs)to enhance training stability and generation capability.
Recently, redactable blockchain has been proposed and leveraged in a wide range of real systems for its unique properties of decentralization, traceability, and transparency while ensuring controllable on-chain data r...
详细信息
Recently, redactable blockchain has been proposed and leveraged in a wide range of real systems for its unique properties of decentralization, traceability, and transparency while ensuring controllable on-chain data redaction. However, the development of redactable blockchain is now obstructed by three limitations, which are data privacy breaches, high communication overhead, and low searching efficiency, respectively. In this paper, we propose PriChain, the first efficient privacy-preserving fine-grained redactable blockchain in decentralized settings. PriChain provides data owners with rights to control who can read and redact on-chain data while maintaining downward compatibility, ensuring the one who can redact will be able to read. Specifically, inspired by the concept of multi-authority attribute-based encryption, we utilize the isomorphism of the access control tree, realizing fine-grained redaction mechanism, downward compatibility, and collusion resistance. With the newly designed structure, PriChain can realize O（n） communication and storage overhead compared to prior O（n2） schemes. Furthermore, we integrate multiple access trees into a tree-based dictionary, optimizing searching efficiency. Theoretical analysis proves that PriChain is secure against the chosen-plaintext attack and has competitive complexity. The experimental evaluations show that PriChain realizes 10× efficiency improvement of searching and 100× lower communication and storage overhead on average compared with existing schemes.
暂无评论