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81.
如何能够在不破坏纠缠态且能将其辨认区分出来是量子信息处理过程中一个很重要的问题,方案首先利用相干光与腔-原子系统的输入-输出过程构造受控相移门,然后利用受控相移门和零差探测技术构造宇称分析器,最后利用宇称分析器和Hadamard等操作构造非破坏性的原子Bell态分析器和原子GHZ态分析器。方案的优势在于:(1)利用到相干光源和零差探测技术,比以往方案中的单光子源和单光子探测较易实现;(2)构造的原子Bell态分析器和原子GHZ态分析器是非破坏性的。方案用到的所有方法和技术在目前的实验上都是可以实现的。 相似文献
82.
This article proposes a new angle difference of directions arrival (ADOA) estimation algorithm. It can estimate the values of ADOA of incidence signals even under channel incoherence environments. It performs an eigenvalue decomposition of a covariance matrix to obtain signal and noise subspace eigenvectors, then estimates the values of ADOA of signals based on the orthogonality between the noise subspace eigenvectors and steering vectors. Its main advantage is that the performance is not degenerated by array elements channel incoherence. In addition, the system complexity is also reduced. Finally, the numerical simulations have been conducted to verify the performance improvement of this algorithm. 相似文献
83.
Catarina Brites João Ascenso Fernando Pereira 《Signal Processing: Image Communication》2013,28(7):689-726
Video coding technologies have played a major role in the explosion of large market digital video applications and services. In this context, the very popular MPEG-x and H-26x video coding standards adopted a predictive coding paradigm, where complex encoders exploit the data redundancy and irrelevancy to ‘control’ much simpler decoders. This codec paradigm fits well applications and services such as digital television and video storage where the decoder complexity is critical, but does not match well the requirements of emerging applications such as visual sensor networks where the encoder complexity is more critical. The Slepian–Wolf and Wyner–Ziv theorems brought the possibility to develop the so-called Wyner–Ziv video codecs, following a different coding paradigm where it is the task of the decoder, and not anymore of the encoder, to (fully or partly) exploit the video redundancy. Theoretically, Wyner–Ziv video coding does not incur in any compression performance penalty regarding the more traditional predictive coding paradigm (at least for certain conditions). In the context of Wyner–Ziv video codecs, the so-called side information, which is a decoder estimate of the original frame to code, plays a critical role in the overall compression performance. For this reason, much research effort has been invested in the past decade to develop increasingly more efficient side information creation methods. This paper has the main objective to review and evaluate the available side information methods after proposing a classification taxonomy to guide this review, allowing to achieve more solid conclusions and better identify the next relevant research challenges. After classifying the side information creation methods into four classes, notably guess, try, hint and learn, the review of the most important techniques in each class and the evaluation of some of them leads to the important conclusion that the side information creation methods provide better rate-distortion (RD) performance depending on the amount of temporal correlation in each video sequence. It became also clear that the best available Wyner–Ziv video coding solutions are almost systematically based on the learn approach. The best solutions are already able to systematically outperform the H.264/AVC Intra, and also the H.264/AVC zero-motion standard solutions for specific types of content. 相似文献
84.
The Chan–Vese (C–V) model is an ineffective method for processing images in which the intensity is inhomogeneous. This is especially true for multi-object segmentation, in which the target may be missed or excessively segmented. In addition, for images with rich texture information, the processing speed of the C–V is slow. To overcome these problems, this paper proposes an effective multi-object C–V segmentation model based on region division and gradient guide. First, a rapid initial contour search is conducted using Otsu’s method. This contour line becomes the initial contour for our multi-object segmentation C–V model based on a gradient guide. To achieve the multi-object segmentation the image is then converted to a single level set whose evolution is controlled using an adaptive gradient. The feasibility of the proposed model is analyzed theoretically, and a number of simulation experiments are conducted to validate its effectiveness. 相似文献
85.
A simple, facile surface sol–gel method is introduced for the fabrication of zirconium oxide films for use as a dielectric layer of a solution-processed polymer field effect transistor (PFET). High dielectric strength is demonstrated for a zirconium oxide layer under room-temperature fabrication conditions using a surface sol–gel method without any post-treatments, which are typically needed in general sol–gel methods. X-ray photoemission spectroscopy showed that the fabricated zirconium oxide layer consists of inorganic ZrO2 and organic alkoxide groups, which can explain its marginal dielectric constant (∼9) and continuous film properties. In addition, by finishing the surface sol–gel synthesis at the stage of chemisorption, the hydrophobic nature of the final surface was retained, leading to a trap-free semiconductor/dielectric interface. As a result, the PFET made with a conventional polymeric semiconductor rendered nearly hysteresis-free and high mobility (0.3 cm2/V) characteristics at low voltage (<2 V). 相似文献
86.
The recombination dynamics of singlet and triplet oppositely charged polarons under the influence of electron–electron (e–e) interactions in coupled polymer chains are investigated using a multi-configurational time-dependent Hartree–Fock (MCTDHF) method. During recombination processes, singlet and triplet intrachain excitons are important products. By calculating the yields of the singlet and triplet intrachain excitons as a function of the on-site and long-range e–e interactions, it is found that the yields of the singlet and triplet intrachain excitons both decrease with increasing on-site e–e interactions. On the other hand, as the long-range e–e interactions increase, the yields of singlet intrachain excitons initially increase and then maintain a constant value, while the yields of the triplet intrachain excitons decrease. Our results show that the long-range e–e interaction is of fundamental importance and improves the luminescence efficiency in coupled polymer chains. Finally, the influence of the polymer chain length on the yields of singlet and triplet intrachain excitons is discussed. 相似文献
87.
88.
《Mechatronics》2015
For a piezoelectric tube scanner (PTS), this paper proposes an improved direct inverse tracking control algorithm and apply it to an atomic force microscope (AFM) to accomplish high-speed scanning tasks. That is, to enhance the high-speed tracking control performance of a PTS, an improved direct inverse rate-dependent Prandtl–Ishlinskii (P–I) model is firstly constructed, which includes a polynomial module to eliminate the structure nonlinearity. Based on the model, a practical feedforward control law is then designed to implement high-speed tracking control for a high-frequency trajectory with strong robustness, which presents the advantages of high-speed response, simple structure and convenient implementation. Subsequently, the designed feedforward law is combined with a feedback component, and the combined control strategy is employed in an AFM to accomplish fast imaging tasks. Numerous experimental results are then collected, which convincingly demonstrate the superior performance of the proposed practical model/control scheme. 相似文献
89.
Combining the Su–Schrieffer–Heeger and Pariser–Parr–Pople model (SSH+PPP), we have studied the influence of electron–electron interactions on the motion and dissociation of a polaron in the presence of an electric field, with emphasis on the long-range Coulomb interactions. The multiconfigurational time-dependent Hartree–Fock (MCTDHF) formalism was used to compute the electron–electron interactions. How the saturated velocity and the critical dissociation electric field of the polaron are related to the on-site Coulomb repulsion and long-range Coulomb interactions has been investigated. It was found that the on-site Coulomb interaction does not favor the motion of a polaron. There is a critical strength of the long-range Coulomb interaction for which the polaron takes on the most localized configuration. Comparing with the results obtained using the extended Hubbard model, we found that competition between the long-range Coulomb interactions and the on-site Coulomb interaction leads to a non-monotonic dependence of both the saturated velocity and the critical dissociation electric field on the long-range Coulomb interactions. 相似文献
90.
《Mechatronics》2022
A large-scale high-precision scan stage is important equipment in the industrial productions of micro-fabrication such as flat panel display (FPD) lithography systems. Designing controllers for multi-input multi-output (MIMO) systems is time-consuming and needs experience because of the interaction between each axis and many controller tuning parameters. The aim of this study is to develop a peak filter design method based on frequency response data to reduce repetitive disturbance. This data-based approach does not use the model and only uses the frequency response data of the controlled system and the disturbance spectrum calculated from the scanning error data (Contribution 1). The peak filter is designed by convex optimization and satisfies robust stability conditions for six-degree-of-freedom systems (Contribution 2). The control performance of the designed peak filter is experimentally demonstrated with an industrial MIMO large-scale high-precision scan stage in reducing the scanning error of the main stroke of the translation along the -axis (Contribution 3). 相似文献