Catálogo de publicaciones - revistas

<jats:p>We examine an amorphous oxide semiconductor (AOS) of ZnRhCuO. The <jats:italic>a</jats:italic>-ZnRhCuO films are deposited at room temperature, having a high amorphous quality with smooth surface, uniform thickness and evenly distributed elements, as well as a high visible transmittance above 87% with a wide bandgap of 3.12 eV. Using <jats:italic>a</jats:italic>-ZnRhCuO films as active layers, thin-film transistors (TFTs) and gas sensors are fabricated. The TFT behaviors demonstrate the p-type nature of <jats:italic>a</jats:italic>-ZnRhCuO channel, with an on-to-off current ratio of ∼ 1 × 10<jats:sup>3</jats:sup> and field-effect mobility of 0.079 cm<jats:sup>2</jats:sup>V<jats:sup>–1</jats:sup>s<jats:sup>–1</jats:sup>. The behaviors of gas sensors also prove that the <jats:italic>a</jats:italic>-ZnRhCuO films are of p-type conductivity. Our achievements relating to p-type <jats:italic>a</jats:italic>-ZnRhCuO films at room temperature with TFT devices may pave the way to practical applications of AOSs in transparent flexible electronics.</jats:p>

<jats:p>Physical systems with gain and loss can be described by a non-Hermitian Hamiltonian, which is degenerated at the exceptional points (EPs). Many new and unexpected features have been explored in the non-Hermitian systems with a great deal of recent interest. One of the most fascinating features is that chiral state conversion appears when one EP is encircled dynamically. Here, we propose an easy-controllable levitated microparticle system that carries a pair of EPs and realize slow evolution of the Hamiltonian along loops in the parameter plane. Utilizing the controllable rotation angle, gain and loss coefficients, we can control the structure, size and location of the loops <jats:italic>in situ</jats:italic>. We demonstrate that, under the joint action of topological structure of energy surfaces and nonadiabatic transitions, the chiral behavior emerges both along a loop encircling an EP and even along a straight path away from the EP. This work broadens the range of parameter space for the chiral state conversion, and proposes a useful platform to explore the interesting properties of exceptional points physics.</jats:p>

<jats:p>Traveling wave solutions have been well studied for various nonlinear systems. However, for high order nonlinear physical models, there still exist various open problems. Here, travelling wave solutions to the well-known fifth-order nonlinear physical model, the Sawada–Kotera equation, are revisited. Abundant travelling wave structures including soliton molecules, soliton lattice, kink-antikink molecules, peak-plateau soliton molecules, few-cycle-pulse solitons, double-peaked and triple-peaked solitons are unearthed.</jats:p>

<jats:p>Very recently the LHCb collaboration reported their observation of the first two fully open-flavor tetraquark states, the <jats:italic>X</jats:italic> <jats:sub>0</jats:sub>(2900) of <jats:italic>J<jats:sup>P</jats:sup> </jats:italic> = 0<jats:sup>+</jats:sup> and the <jats:italic>X</jats:italic> <jats:sub>1</jats:sub>(2900) of <jats:italic>J<jats:sup>P</jats:sup> </jats:italic> = 1<jats:sup>−</jats:sup>. We study their possible interpretations using the method of QCD sum rules, paying special attention to an interesting feature of this experiment that the higher resonance <jats:italic>X</jats:italic> <jats:sub>1</jats:sub>(2900) has a width significantly larger than the lower one <jats:italic>X</jats:italic> <jats:sub>0</jats:sub>(2900). Our results suggest that the <jats:italic>X</jats:italic> <jats:sub>0</jats:sub>(2900) can be interpreted as the s-wave <jats:italic>D</jats:italic> <jats:sup>*–</jats:sup> <jats:italic>K</jats:italic> <jats:sup>*+</jats:sup> molecule state of <jats:italic>J<jats:sup>P</jats:sup> </jats:italic> = 0<jats:sup>+</jats:sup>, and the <jats:italic>X</jats:italic> <jats:sub>1</jats:sub>(2900) can be interpreted as the p-wave <jats:inline-formula> <jats:tex-math><?CDATA $\bar{c}\bar{s}ud$?></jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mover accent="true"> <mml:mi>c</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mover accent="true"> <mml:mi>s</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mi>u</mml:mi> <mml:mi>d</mml:mi> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_10_101201_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> compact tetraquark state of <jats:italic>J<jats:sup>P</jats:sup> </jats:italic> = 1<jats:sup>−</jats:sup>. Mass predictions of their bottom partners are also given.</jats:p>

<jats:p>Motivated by the recent ATLAS results in terms of the branching ratios <jats:italic>Br</jats:italic>(<jats:italic>t</jats:italic> → <jats:italic>qγ</jats:italic>), we consider the effects of the anomalous <jats:italic>tqγ</jats:italic> couplings on the radiative <jats:italic>B</jats:italic> meson decays <jats:inline-formula> <jats:tex-math> <?CDATA $\bar{B}\to {X}_{D}\gamma $?> </jats:tex-math> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mover accent="true"> <mml:mi>B</mml:mi> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> <mml:mo>→</mml:mo> <mml:msub> <mml:mi>X</mml:mi> <mml:mi>D</mml:mi> </mml:msub> <mml:mi>γ</mml:mi> </mml:mrow> </mml:math> <jats:inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cpl_37_10_101301_ieqn1.gif" xlink:type="simple" /> </jats:inline-formula> and <jats:italic>B</jats:italic> → <jats:italic>Vγ</jats:italic> with <jats:italic>V</jats:italic> being light vector mesons <jats:italic>ρ</jats:italic>, <jats:italic>ω</jats:italic>, <jats:italic>ϕ</jats:italic> and <jats:italic>K</jats:italic> <jats:sup>*</jats:sup>. Comparing with the corresponding experimental measured data, we obtain the constraints on anomalous <jats:italic>tqγ</jats:italic> couplings.</jats:p>

<jats:p>We present a general machine learning based scheme to optimize experimental control. The method utilizes the neural network to learn the relation between the control parameters and the control goal, with which the optimal control parameters can be obtained. The main challenge of this approach is that the labeled data obtained from experiments are not abundant. The central idea of our scheme is to use the active learning to overcome this difficulty. As a demonstration example, we apply our method to control evaporative cooling experiments in cold atoms. We have first tested our method with simulated data and then applied our method to real experiments. It is demonstrated that our method can successfully reach the best performance within hundreds of experimental runs. Our method does not require knowledge of the experimental system as a prior and is universal for experimental control in different systems.</jats:p>

<jats:p>We demonstrate a tunable bandpass optical filter based on a tapered optical fiber (TOF) touched by a hemispherical microfiber tip (MFT). Other than the interference and selective material absorption effects, the filter relies on the controllable and wavelength-dependent mode–mode interactions in TOF. Experimentally, a large range of tunability is realized by controlling the position of the MFT in contact with the TOF for various TOF radii, and two distinct bandpass filter mechanisms are demonstrated. The center wavelength of the bandpass filter can be tuned from 890 nm to 1000 nm, while the FWHM bandwidth can be tuned from 110 nm to 240 nm when the MFT touches the TOF in the radius range from 160 nm to 390 nm. The distinction ratio can reach 28 ± 3 dB experimentally. The combined TOF-MFT is an in-line tunable bandpass optical filter that has great application potential in optical networks and spectroscopy, and the principle could also be generalized to other integrated photonic devices.</jats:p>

<jats:p>The microscopic mechanism of thermal transport in liquids and amorphous solids has been an outstanding problem for a long time. There have been several approaches to explain the thermal conductivities in these systems, for example, Bridgman’s formula for simple liquids, the concept of the minimum thermal conductivity for amorphous solids, and the thermal resistance network model for amorphous polymers. Here, we present a ubiquitous formula to calculate the thermal conductivities of liquids and amorphous solids in a unified way, and compare it with previous ones. The calculated thermal conductivities using this formula without fitting parameters are in excellent agreement with the experimental data. Our formula not only provides a detailed microscopic mechanism of heat transfer in these systems, but also resolves the discrepancies between existing formulae and experimental data.</jats:p>

<jats:p>Molecular dynamics simulations are performed to gain insights into the structural and vibrational properties of interface between porous and fused silica. The Si–O bonds formed in the interface exhibit the same lengths as the bulk material, whereas the coordination defects in the interface are at an intermediate level as compared with the dense and porous structures. Clustered bonds are identified from the interface, which are associated with the reorganization of the silica surface. The bond angle distributions show that the O–Si–O bond angles keep the average value of 109°, whereas the Si–O–Si angles of the interface present in a similar manner to those in porous silica. Despite the slight structural differences, similarities in the vibrations are observed, which could further demonstrate the stability of porous silica films coated on the fused silica.</jats:p>