Catálogo de publicaciones - revistas

<jats:p>We reveal the electronic structure in YbCd<jats:sub>2</jats:sub>Sb<jats:sub>2</jats:sub>, a thermoelectric material, by angle-resolved photoemission spectroscopy (ARPES) and time-resolved ARPES (trARPES). Specifically, three bulk bands at the vicinity of the Fermi level are evidenced near the Brillouin zone center, consistent with the density functional theory (DFT) calculation. It is interesting that the spin-unpolarized bulk bands respond unexpectedly to right- and left-handed circularly polarized probe. In addition, a hole band of surface states, which is not sensitive to the polarization of the probe beam and is not expected from the DFT calculation, is identified. We find that the non-equilibrium quasiparticle recovery rate is much smaller in the surface states than that of the bulk states. Our results demonstrate that the surface states can be distinguished from the bulk ones from a view of time scale in the nonequilibrium physics.</jats:p>

<jats:p>Organic semiconductors, especially polymer semiconductors, have attracted extensive attention as organic thermoelectric materials due to their capabilities for flexibility, low-cost fabrication, solution processability and low thermal conductivity. However, it is challenging to obtain high-performance organic thermoelectric materials because of the low intrinsic carrier concentration of organic semiconductors. The main method to control the carrier concentration of polymers is the chemical doping process by charge transfer between polymer and dopant. Therefore, the deep understanding of doping mechanisms from the point view of chemical structure has been highly desired to overcome the bottlenecks in polymeric thermoelectrics. In this contribution, we will briefly review the recently emerging progress for discovering the structure–property relationship of organic thermoelectric materials with high performance. Highlights include some achievements about doping strategies to effectively modulate the carrier concentration, the design rules of building blocks and side chains to enhance charge transport and improve the doping efficiency. Finally, we will give our viewpoints on the challenges and opportunities in the field of polymer thermoelectric materials.</jats:p>

<jats:p>With the growing need on distributed power supply for portable electronics, energy harvesting from environment becomes a promising solution. Organic thermoelectric (TE) materials have advantages in intrinsic flexibility and low thermal conductivity, thus hold great prospect in applications as a flexible power generator from dissipated heat. Nevertheless, the weak electrical transport behaviors of organic TE materials have severely impeded their development. Moreover, compared with p-type organic TE materials, stable and high-performance n-type counterparts are more difficult to obtain. Here, we developed a n-type polyaniline-based hybrid with core-shell heterostructured Bi<jats:sub>2</jats:sub>S<jats:sub>3</jats:sub>@Bi nanorods as fillers, showing a Seebeck coefficient –159.4 μV/K at room temperature. Further, a couple of n/p legs from the PANI-based hybrids were integrated into an elastomer substrate forming a stretchable thermoelectric generator (TEG), whose function to output stable voltages responding to temperature differences has been demonstrated. The <jats:italic>in situ</jats:italic> output performance of the TEG under stretching could withstand up to 75% elongation, and stability test showed little degradation over a one-month period in the air. This study provides a promising strategy to develop stable and high thermopower organic TEGs harvesting heat from environment as long-term power supply.</jats:p>

<jats:p>The <jats:italic>in vivo</jats:italic> tumor microenvironment is a complex niche that includes heterogeneous physical structures, unique biochemical gradients and multiple cell interactions. Its high-fidelity <jats:italic>in vitro</jats:italic> reconstruction is of fundamental importance to improve current understandings of cell behavior, efficacy predictions and drug safety. In this study, we have developed a high-throughput biochip with hundreds of composite extracellular matrix (ECM) microchambers to co-culture invasive breast cancer cells (MDA-MB-231-RFP) and normal breast epithelial cells (MCF-10A-GFP). The composite ECM is composed of type I collagen and Matrigel which provides a heterogeneous microenvironment that is similar to that of <jats:italic>in vivo</jats:italic> cell growth. Additionally, the growth factors and drug gradients that involve human epidermal growth factor (EGF), discoidin domain receptor 1 (DDR1) inhibitor 7rh and matrix metalloproteinase inhibitor batimastat allow for the mimicking of the complex <jats:italic>in vivo</jats:italic> biochemical microenvironment to investigate their effect on the spatial-temporal dynamics of cell growth. Our results demonstrate that the MDA-MB-231-RFP cells and MCF-10A-GFP cells exhibit different spatial proliferation behaviors under the combination of growth factors and drugs. Basing on the experimental data, we have also developed a cellular automata (CA) model that incorporated drug diffusion to describe the experimental phenomenon, as well as employed Shannon entropy (SE) to explore the effect of the drug diffusion coefficient on the spatial-temporal dynamics of cell growth. The results indicate that the uniform cell growth is related to the drug diffusion coefficient, which reveals that the pore size of the ECM plays a key role in the formation of complex biochemical gradients. Therefore, our integrated, biomimetic and high-throughput co-culture platforms, as well as the computational model can be used as an effective tool for investigating cancer pathogenesis and drug development.</jats:p>

<jats:p>Taking the advantage of “parity kicks” pulses, we investigate the non-classical correlation dynamics and quantum state transfer in an atom–cavity–fiber system, which consists of two identical subsystems, each subsystem comprising of multiple two-level atoms trapped in two remote single-model optical cavities that are linked by an optical fiber. It is found that the non-classical correlations and the fidelity of quantum state transfer (between the atoms) can be greatly improved by the parity kicks pulses. In particular, with decrease of the time intervals between two consecutive pulses, perfect non-classical correlation transfer and entangled state transfer can be achieved.</jats:p>

<jats:p>We study the traveling wave and other solutions of the perturbed Kaup–Newell Schrödinger dynamical equation that signifies long waves parallel to the magnetic field. The wave solutions such as bright-dark (solitons), solitary waves, periodic and other wave solutions of the perturbed Kaup–Newell Schrödinger equation in mathematical physics are achieved by utilizing two mathematical techniques, namely, the extended F-expansion technique and the proposed exp(–<jats:italic>ϕ</jats:italic>(<jats:italic>ζ</jats:italic>))-expansion technique. This dynamical model describes propagation of pluses in optical fibers and can be observed as a special case of the generalized higher order nonlinear Schrödinger equation. In engineering and applied physics, these wave results have key applications. Graphically, the structures of some solutions are presented by giving specific values to parameters. By using modulation instability analysis, the stability of the model is tested, which shows that the model is stable and the solutions are exact. These techniques can be fruitfully employed to further sculpt models that arise in mathematical physics.</jats:p>

<jats:p>A local refinement hybrid scheme (LRCSPH-FDM) is proposed to solve the two-dimensional (2D) time fractional nonlinear Schrödinger equation (TF-NLSE) in regularly or irregularly shaped domains, and extends the scheme to predict the quantum mechanical properties governed by the time fractional Gross–Pitaevskii equation (TF-GPE) with the rotating Bose–Einstein condensate. It is the first application of the purely meshless method to the TF-NLSE to the author’s knowledge. The proposed LRCSPH-FDM (which is based on a local refinement corrected SPH method combined with FDM) is derived by using the finite difference scheme (FDM) to discretize the Caputo TF term, followed by using a corrected smoothed particle hydrodynamics (CSPH) scheme continuously without using the kernel derivative to approximate the spatial derivatives. Meanwhile, the local refinement technique is adopted to reduce the numerical error. In numerical simulations, the complex irregular geometry is considered to show the flexibility of the purely meshless particle method and its advantages over the grid-based method. The numerical convergence rate and merits of the proposed LRCSPH-FDM are illustrated by solving several 1D/2D (where 1D stands for one-dimensional) analytical TF-NLSEs in a rectangular region (with regular or irregular particle distribution) or in a region with irregular geometry. The proposed method is then used to predict the complex nonlinear dynamic characters of 2D TF-NLSE/TF-GPE in a complex irregular domain, and the results from the posed method are compared with those from the FDM. All the numerical results show that the present method has a good accuracy and flexible application capacity for the TF-NLSE/GPE in regions of a complex shape.</jats:p>

<jats:p>We investigate properties of the ponderomotive squeezing in an optomechanical system with two coupled resonators, where the tunable two-mode squeezing spectrum can be observed from the output field. It is realized that the squeezing orientation can be controlled by the detuning between the left cavity and pump laser. Especially, both cavity decay and environment temperature play a positive role in generating better pondermotive squeezing light. Strong squeezing spectra with a wide squeezing frequency range can be obtained by appropriate choice of parameters present in our optomechanical system.</jats:p>

<jats:p>Perfect state transfer (PST) has great significance due to its applications in quantum information processing and quantum computation. The main problem we study in this paper is to determine whether the two-fold Cayley tree, an extension of the Cayley tree, admits perfect state transfer between two roots using quantum walks. We show that PST can be achieved by means of the so-called nonrepeating quantum walk [<jats:italic>Phys. Rev. A</jats:italic> <jats:bold>89</jats:bold> 042332 (2014)] within time steps that are the distance between the two roots; while both the continuous-time quantum walk and the typical discrete-time quantum walk with Grover coin approaches fail. Our results suggest that in some cases the dynamics of a discrete-time quantum walk may be much richer than that of the continuous-time quantum walk.</jats:p>

<jats:p>Quantum information processing based on Rydberg atoms emerged as a promising direction two decades ago. Recent experimental and theoretical progresses have shined exciting light on this avenue. In this concise review, we will briefly introduce the basics of Rydberg atoms and their recent applications in associated areas of neutral atom quantum computation and simulation. We shall also include related discussions on quantum optics with Rydberg atomic ensembles, which are increasingly used to explore quantum computation and quantum simulation with photons.</jats:p>