Catálogo de publicaciones - revistas

<jats:p>The vertical GaN-on-GaN Schottky barrier diode with boron-implanted termination was fabricated and characterized. Compared with the Schottky barrier diode (SBD) without boron-implanted termination, this SBD effectively improved the breakdown voltage from 189 V to 585 V and significantly reduced the reverse leakage current by 10<jats:sup>5</jats:sup> times. In addition, a high <jats:italic>I</jats:italic> <jats:sub>on</jats:sub>/<jats:italic>I</jats:italic> <jats:sub>off</jats:sub> ratio of ∼10<jats:sup>8</jats:sup> was achieved by the boron-implanted technology. We used Technology Computer Aided Design (TCAD) to analyze reasons for the improved performance of the SBD with boron-implanted termination. The improved performance of diodes may be attributed to that B<jats:sup>+</jats:sup> could confine free carriers to suppress electron field crowding at the edge of the diode, which could improve the breakdown voltage and suppress the reverse leakage current.</jats:p>

<jats:p>High resolution Fresnel zone plates for nanoscale three-dimensional imaging of materials by both soft and hard x-rays are increasingly needed by the broad applications in nanoscience and nanotechnology. When the outmost zone-width is shrinking down to 50 nm or even below, patterning the zone plates with high aspect ratio by electron beam lithography still remains a challenge because of the proximity effect. The uneven charge distribution in the exposed resist is still frequently observed even after standard proximity effect correction (PEC), because of the large variety in the line width. This work develops a new strategy, nicknamed as local proximity effect correction (LPEC), efficiently modifying the deposited energy over the whole zone plate on the top of proximity effect correction. By this way, 50 nm zone plates with the aspect ratio from 4 : 1 up to 15 : 1 and the duty cycle close to 0.5 have been fabricated. Their imaging capability in soft (1.3 keV) and hard (9 keV) x-ray, respectively, has been demonstrated in Shanghai Synchrotron Radiation Facility (SSRF) with the resolution of 50 nm. The local proximity effect correction developed in this work should also be generally significant for the generation of zone plates with high resolutions beyond 50 nm.</jats:p>

<jats:p>Developing moisture-sensitive artificial muscles from industrialized natural fibers with large abundance is highly desired for smart textiles that can respond to humidity or temperature change. However, currently most of fiber artificial muscles are based on non-common industrial textile materials or of a small portion of global textile fiber market. In this paper, we developed moisture-sensitive torsional artificial muscles and textiles based on cotton yarns. It was prepared by twisting the cotton yarn followed by folding in the middle point to form a self-balanced structure. The cotton yarn muscle showed a torsional stroke of 42.55 °/mm and a rotational speed of 720 rpm upon exposure to water moisture. Good reversibility and retention of stroke during cyclic exposure and removal of water moisture were obtained. A moisture-sensitive smart window that can close when it rains was demonstrated based on the torsional cotton yarn muscles. This twist-based technique combining natural textile fibers provides a new insight for construction of smart textile materials.</jats:p>

<jats:p>Safety requirements stimulate Na-based batteries to evolve from high-temperature Na–S batteries to room-temperature Na-ion batteries (NIBs). Even so, NIBs may still cause thermal runaway due to the external unexpected accidents and internal high activity of electrodes or electrolytes, which has not been comprehensively summarized yet. In this review, we summarize the significant advances about the failure mechanisms and related strategies to build safer NIBs from the selection of electrodes, electrolytes and the construction of electrode/electrolyte interfaces. Considering the safety risk, the thermal behaviors are emphasized which will deepen the understanding of thermal stability of different NIBs and accelerate the exploitation of safe NIBs.</jats:p>

<jats:p>The eight-band <jats:bold> <jats:italic>k</jats:italic> </jats:bold>⋅<jats:bold> <jats:italic>p</jats:italic> </jats:bold> model is used to establish the energy band structure model of the type-II InAs/GaSb superlattice detectors with a cut-off wavelength of 10.5 μm, and the best composition of M-structure in this type of device is calculated theoretically. In addition, we have also experimented on the devices designed with the best performance to investigate the effect of the active region p-type doping temperature on the quantum efficiency of the device. The results show that the modest active region doping temperature (Be: 760 °C) can improve the quantum efficiency of the device with the best performance, while excessive doping (Be: &gt; 760 °C) is not conducive to improving the photo response. With the best designed structure and an appropriate doping concentration, a maximum quantum efficiency of 45% is achieved with a resistance–area product of 688 Ω ⋅cm<jats:sup>2</jats:sup>, corresponding to a maximum detectivity of 7.35 × 10<jats:sup>11</jats:sup>cm ⋅ Hz<jats:sup>1/2</jats:sup>/W.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We study the dynamics of the entropic uncertainty for three types of three-level atomic systems coupled to an environment modeled by random matrices. The results show that the entropic uncertainty in the Ξ type atomic system is lower than that in the <jats:italic>V</jats:italic> type atomic system which is exactly the same as that in the Λ type atomic system. In addition, the effect of relative coupling strength on entropic uncertainty is opposite in Markov region and non-Markov region, and the influence of a common environment and independent environments in Markov region and non-Markov region is also opposite. One can reduce the entropic uncertainty by decreasing relative coupling strength or placing the system in two separate environments in the Markov case. In the non-Markov case, the entropic uncertainty can be reduced by increasing the relative coupling strength or by placing the system in a common environment.</jats:p>

<jats:p>The nonlocal symmetries are derived for the Korteweg–de Vries–negative-order Korteweg–de Vries equation from the Painlevé truncation method. The nonlocal symmetries are localized to the classical Lie point symmetries for the enlarged system by introducing new dependent variables. The corresponding similarity reduction equations are obtained with different constant selections. Many explicit solutions for the integrable equation can be presented from the similarity reduction.</jats:p>

<jats:p>The finite-time Mittag–Leffler synchronization is investigated for fractional-order delayed memristive neural networks (FDMNN) with parameters uncertainty and discontinuous activation functions. The relevant results are obtained under the framework of Filippov for such systems. Firstly, the novel feedback controller, which includes the discontinuous functions and time delays, is proposed to investigate such systems. Secondly, the conditions on finite-time Mittag–Leffler synchronization of FDMNN are established according to the properties of fractional-order calculus and inequality analysis technique. At the same time, the upper bound of the settling time for Mittag–Leffler synchronization is accurately estimated. In addition, by selecting the appropriate parameters of the designed controller and utilizing the comparison theorem for fractional-order systems, the global asymptotic synchronization is achieved as a corollary. Finally, a numerical example is given to indicate the correctness of the obtained conclusions.</jats:p>

<jats:p>Reconciliation is a necessary step in postprocessing of continuous-variable quantum key distribution (CV-QKD) system. We use globally coupled low-density parity-check (GC-LDPC) codes in reconciliation to extract a precise secret key from the raw keys over the authenticated classical public channel between two users. GC-LDPC codes have excellent performance over both the additive Gaussian white noise and binary-erasure channels. The reconciliation based on GC-LDPC codes can improve the reconciliation efficiency to 95.42% and reduce the frame error rate to 3.25 × 10<jats:sup>–3</jats:sup>. Using distillation, the decoding speed can achieve 23.8 Mbits/s and decrease the cost of memory. Given decoding speed and low memory usage, this makes the proposed reconciliation method viable approach for high-speed CV-QKD system.</jats:p>

<jats:p>Kerr nonlinearity is an important resource for creating squeezing and entanglement in quantum technology. Here we propose a scheme for generating Kerr nonlinearity originated from an engineered non-Markovian environment, which is different from the previous efforts using nonlinear media or quantum systems with special energy structures. In the present work, the generation of Kerr nonlinearity depends on the system–environment interaction time, the energy spectrum of the environment, and the system–environment coupling strength, regardless of the environmental initial state. The scheme can be realized in systems originally containing no Kerr interaction, such as superconducting circuit systems, optomechanical systems, and cavity arrays connected by transmission lines.</jats:p>