Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>We investigate few-photons scattering properties in two one-dimensional waveguides chirally coupled to a nonlinear cavity. The quantum states of scattered few-photons are solved analytically via a real-space approach, and the solution indicates the few-photons reflection and transmission properties. When inputing two photons of equal energy to resonate with the cavity, the propagation characteristics of the two photons will be interesting, which is different from the previous anti-bunching effects with a quantum emitter. More importantly, when the total energy of the two incident photons equals the energy of a nonlinear cavity accommodating two photons, the bound state will become larger influence resulting in the disappearance of the antibunching effect. However, the bound state have no effect the probability of routing to another waveguide.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Light absorption and radiation process is one of the fundamental processes in optical science and engineering. Materials with perfect absorption properties play an important role in numerous optical applications. Following the meteoric rise of MoS<jats:sub>2</jats:sub> material, global opportunities and challenges coexisted since its extremely weak light-matter interaction capability beyond its energy band. In this work, we designed a kind of sandwich resonance structure and expressed MoS<jats:sub>2</jats:sub> first as a perfect absorber in infrared spectrum that should be transparent according to optical band theory. The infrared absorption properties of W or Au/MoS<jats:sub>2</jats:sub>/Au models in 800–2400 nm were systematic simulated. By optimizing the structural parameters, the resonant wavelength of perfect absorption can be modulated from 830 to 1700 nm with angle-insensitivity and polar-independence. Moreover, we discovered the bandwidth of absorption exceeding 50% of W-top model reaches 500 nm, while that of Au-top model is less than 100 nm, indicating the top metal material used have a great influence on the resonance absorption spectrum. Our works provide a practical route to enhance and manipulate the light-matter interactions of low-dimensional materials beyond their own band gaps, which will be critical in the future design and implementation of optoelectronic devices and systems.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Novel electromagnetic wave modulation by programmable dynamic metasurface promotes the device design freedom, while multibeam antennas have sparked tremendous interest in wireless communications. A programmable coding antenna based on active metasurface elements (AMSEs) is proposed in this study, allowing scanning and state switching of multiple beams in real time. To obtain the planar array phase distribution in quick response, the aperture field superposition and discretization procedures are investigated. Without the need for a massive algorithm or elaborate design, this electronically controlled antenna with integrated radiation and phase-shift functions can flexibly manipulate the scattering state of multiple beams under field-programmable gate array (FPGA) control. Simulation and experimental results show that the multiple directional beams dynamically generated in the metasurface upper half space have good radiation performance, with the main lobe directions closely matching the predesigned angles. This metasurface antenna has great potential for future applications in multitarget radar, satellite navigation, and reconfigurable intelligent metasurfaces.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Acoustic characteristics of the detonation sound wave generated by a pulse detonation engine with an annular nozzle, including peak sound pressure, directivity, and A duration, are experimentally investigated while utilizing gasoline as fuel and air as oxidizer. Three annular nozzle geometries are evaluated by varying the ratio of inner cone diameter to detonation tube exit diameter from 0.36 to 0.68. The experimental results show that the annular nozzles have a significant effect on the acoustic characteristics of the detonation sound wave. The annular nozzles can amplify the peak sound pressure of the detonation sound wave at 90 deg while reducing it at 0 deg and 30 deg. The directivity angle of the detonation sound wave is changed by annular nozzles from 30 deg to 90 deg. The A duration of the detonation sound wave at 90 deg is also increased by the annular nozzles. These changes indicate that the annular nozzles have an important influence on the acoustic energy distribution of the detonation sound wave, which amplify the acoustic energy in a direction perpendicular to the tube axis and weaken it along the direction of the tube axis.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Inspired by the activity-based sensing methods, the hydrazine-modified naphthalene derivative (Naph1) was synthesized and used as a fluorescent probe to detect formaldehyde (FA) in living cells. Through the condensation reaction between the probe Naph1 and analyte FA, researchers observed a ~14 folds enhancement of fluorescent signal around 510 nm in an experiment, realizing the high selectivity and sensitivity detection of FA. However, a theoretical understanding of the sensing mechanism was not provided in the experimental work. Given this, the light-up fluorescent detecting mechanism was in-depth unveiled by performing the timedependent density functional theory (TDDFT) and the complete active space selfconsistent field (CASSCF) theoretical calculations on excited-state intramolecular proton transfer (ESIPT) and non-adiabatic excited-state dynamics simulation. The deactivation channel of S<jats:sub>1</jats:sub>/T<jats:sub>2</jats:sub> intersystem crossing (ISC) was turned off to successfully recognize FA. Insight into the ESIPT-based fluorescent detecting mechanism indicated that ESIPT was essential to light-up fluorescent probes. This work would provide a new viewpoint to develop ESIPT-based fluorescent probes for detecting reactive carbon species in vivo or vitio.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>One-dimensional (1D) micro/nanowires of wide band gap semiconductors have become one of the most promising blocks of high-performance photodetectors. However, in the axial direction of micro/nanowires, the carriers can transport freely driven by external electric field, which usually produces large dark current and low detectivity. Here, an UV photodetector built from three cross-intersecting ZnO microwires with double homo-interfaces is demonstrated by the chemical vapor deposition and physical transfer techniques. Compared with the reference device without interface, the dark current of this ZnO double-interface photodetector is significantly reduced by nearly 5 orders of magnitude, while the responsivity decreases slightly, thereby greatly improving the normalized photocurrent-to-dark current ratio. In addition, ZnO double-interface photodetector exhibits a much faster response speed (~0.65 s) than the no-interface device (~95 s). The improved performance is attributed to the potential barriers at the microwire-microwire homo-interfaces, which can regulate the carrier transport. Our findings in this work provide a promising approach for the design and development of high-performance photodetectors.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Glide dislocations with periodic pentagon-heptagon pairs are investigated within the theory of 1D misfit dislocations in the framework of an improved Peierls–Nabarro (P–N) equation in which the lattice discreteness is fully considered. We find an approximate solution to handle misfit dislocations, where the second-order derivative appears in the improved P–N equation. This result is practical for periodic glide dislocations with narrow width, and those in the BN/AlN heterojunction are studied. The structure of the misfit dislocations and adhesion work are obtained explicitly and verified by first-principles calculations. Compared with shuffle dislocations, the compression force in the tangential direction of glide dislocations has a greater impact on the normal direction, and the contributions of the normal displacement to the interfacial energy cannot simply be ignored.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The single-file movement experiment offers a convenient way to investigate the one-dimensional leader-follower behavior of pedestrians. This study investigated the time delays of children pedestrians in the leader-follower behavior by introducing a time-dependent delayed speed correlation. A total of 118 German students from the fifth grade (aged 11-12 years old) and the 11th grade (aged 17-18 years old) participated the single-file experiment. The characteristic delay time for each pedestrian was identified by optimising the time-dependent delayed speed correlation. The influences of the curvature of the experimental scenario, density, age, and gender on the delay time were statistically examined. The results suggested that to a large extent, the revealed characteristic delay time was a density-dependent variable, and none of the curvatures, the age and gender of the individual, and the age and gender of the leader have a significant influence on it. The findings from this study are variable resources to understand the leader-follower behavior among children pedestrians and to build related simulation models.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The on-surface synthesis method allows the fabrication of atomically precise narrow graphene nanoribbons(GNRs), which bears great potential in electronic applications. Here, we synthetic armchair graphene nanoribbons (AGNRs) and chevron-type graphene nanoribbons (CGNRs) array on a vicinal Au (11 11 12) surface using 10,10′-dibromo-9,9′-bianthracene(DBBA) and 6,12-dibromochrysene(DBCh) as precursors, respectively. This process creates spatially well-aligned GNRs, as characterized by scanning tunneling microscopy. AGNRs show strong Raman linear polarizability for application in optical modulation devices. Different from the distinct polarization of AGNRs, only weak polarization exists in CGNRs polarized Raman spectrum, which suggests the presence of the zigzag boundary in the nanoribbon attenuates the polarization rate as an important factor affecting the polarization. We analyzed the Raman activation mode of CGNRs using the peak polarization to expand the application of polarization Raman spectroscopy in nanoarray analysis.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>A novel Silicon Carbide gate-controlled bipolar field effect composite transistor with polysilicon region (SiC GCBTP) is proposed. Different from the traditional electrode connection mode of SiC VDMOS, the P+ region of P-well is connected with the gate in SiC GCBTP, and the polysilicon region is added between the P+ region and the gate. By this method, additional minority carriers can be injected into the drift region in on-state, and the distribution of minority carriers in the drift region will be optimized, so the on-state current is increased. In terms of static characteristics, it has the same high breakdown voltage (811V) as SiC VDMOS which length of drift is 5.5 μm. The on-state current of SiC GCBTP is 2.47×10<jats:sup>-3</jats:sup> A/μm (<jats:italic>V</jats:italic> <jats:sub>G</jats:sub>=10V, <jats:italic>V</jats:italic> <jats:sub>D</jats:sub>=10V) which is 5.7 times that of SiC IGBT and 36.4 times that of SiC VDMOS. In terms of dynamic characteristics, the turn-on time of SiC GCBTP is only 0.425ns. And the turn-off time of SiC GCBTP is similar to SIC IGBT, which is 114.72ns.</jats:p>