Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>Experimental records in the cerebral cortex indicate that ammonia injection can lead to seizures. Considering that astrocytes play a vital role in mediating the uptake and absorption of ammonium ions in the extracellular space of the cortical circuit, we constructed a new astrocyte neuron coupling model, which is composed of a neuron and its astrocytes connected through the extracellular space, taking into account the influence of extracellular ammonium ions. The numerical results verified the previous experimental observation that obtained epileptic firing modes of neurons and postsynaptic GABA reversal potential depolarization triggered by ammonia injection. In addition, we also determined the concentration-response relationship between the ammonium ion concentration and the time of entering epilepsy and predicted the threshold of the ammonium ion concentration for the onset of epilepsy.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Here, we report the layering and liquid-liquid phase transition of the liquid titanium confined between two parallel panel walls. Abnormal changes in the volume and the potential energy confirm the existence of the liquid-liquid phase transition of the liquid titanium. The typical feature of the liquid-liquid phase transition is layering which is induced by the slit size, pressure and temperature. We highlight that the slit size and pressure would determine the number of the layers. In addition, with the change of the slit size, the density of the confined liquid expresses a fluctuating law. The phase diagram of the layering transition has been drawn to well understand the layering. This study provides insight into the liquid-liquid phase transition of the liquid metal in confined space.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>By using the difference of the band structure for the TE and TM waves in the metal-dielectric photonic crystals beyond the light cone and the birefringence of the anisotropic crystal, a one-dimensional photonic system is constructed to realize the bound states in the continuum (BICs). In addition to the BICs arising from the polarization incompatibility, the Friedrich-Wintgen BICs are also achieved when the leaking TM wave is eliminated due to the destructive interference of its ordinary and extraordinary wave components in the anisotropic crystal. A modified scheme favorable for practical application is also proposed. This scheme for BICs may help to suppress the radiation loss in the metal-dielectric photonic crystal systems.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The transition metal dichalcogenides (TMD) monolayers have shown strong second-harmonic generation (SHG) owing to their lack of inversion symmetry. These ultrathin layers then serve as the frequency converters that can be intergraded on a chip. Here, with MoSSe as an example, we report the first detailed experimental study of the SHG of Janus TMD monolayer, in which the transition metal layer is sandwiched by the two distinct chalcogen layers. We show that the SHG effectively arises from an in-plane second-harmonic polarization under paraxial focusing and detection. Based on this, the orientation-resolved SHG spectroscopy is realized to readily determine the zigzag and armchair axes of the Janus crystal with an accuracy better than ±0.6°. Moreover, the SHG intensity is wavelength-dependent and can be greatly enhanced (~60 times) when the two-photon transition is resonant with the C-exciton state. Our findings uncover the SHG properties of Janus MoSSe monolayer, therefore lay the basis for its integrated frequency-doubling applications.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The peculiar plasmon resonance characteristics of nanostructures based on metal clusters have always been the focus of various plasmon devices and different applications. We have studied the plasmon resonance phenomenon of polyhedral silver clusters under the adsorption of NH<jats:sub>3</jats:sub>, N<jats:sub>2</jats:sub>, H<jats:sub>2</jats:sub> and CH<jats:sub>4</jats:sub> molecules using time-dependent density functional theory. Under the adsorption of NH<jats:sub>3</jats:sub>, the tunneling current of silver clusters changed significantly due to the charge transfer from NH<jats:sub>3</jats:sub> to silver clusters. However, the effects of N<jats:sub>2</jats:sub>, H<jats:sub>2</jats:sub> and CH<jats:sub>4</jats:sub> adsorption on the tunneling current of silver clusters are negligible. Our results indicate that these silver clusters exhibit excellent selectivity and sensitivity for NH<jats:sub>3</jats:sub> detection. These findings confirm that silver clusters are promising NH<jats:sub>3</jats:sub> sensor and provide new avenue for the design of high-performance sensors in the future.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this work, we have systematically performed structure searching for Sr-Ge system under pressure up to 200 GPa and found six stable stoichiometries as Sr<jats:sub>3</jats:sub>Ge, Sr<jats:sub>2</jats:sub>Ge, SrGe, SrGe<jats:sub>2</jats:sub>, SrGe<jats:sub>3</jats:sub> and SrGe<jats:sub>4</jats:sub>. We demonstrated the interesting structure evolution behaviors in Sr-Ge system with increased germanium content, the Ge atoms arranging from isolated anions in Sr<jats:sub>3</jats:sub>Ge, chains in Sr<jats:sub>2</jats:sub>Ge, square units in SrGe, trigonal units and hexahedrons in SrGe<jats:sub>2</jats:sub>, cages in SrGe<jats:sub>3</jats:sub>, hexagons and Ge<jats:sub>8</jats:sub> rings in SrGe<jats:sub>4</jats:sub>. The structural diversity produces various manifestations of electronic structures, which are benefit for electrical transportation. Among them, these novel phases with metallic structures show superconductivity (maximum <jats:italic>T</jats:italic> <jats:sub>c</jats:sub> ~ 8.94 K for <jats:italic>Pmmn</jats:italic> Sr<jats:sub>3</jats:sub>Ge). Notably, the <jats:italic>n</jats:italic>-type semiconducting <jats:italic>Pnma</jats:italic> SrGe<jats:sub>2</jats:sub> structure exhibits high Seebeck coefficient and excellent electrical conductivity along <jats:italic>y</jats:italic> direction, leading to a high ZT value up to 1.55 at 500 K, which can be potential candidates as high-performance thermoelectrics. Our results would enable the development of fundamental science in condensed matter physics and potential applications in novel electronics or thermoelectric materials.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Van der Waals heterostructures based on two-dimensional (2D) semiconductor materials have attracted increasing attention due to their attractive properties. In this work, we demonstrate a high-sensitive back-gated phototransistor based on vertical HfSe<jats:sub>2</jats:sub>/MoS<jats:sub>2</jats:sub> heterostructure with a broad-spectral response from near-ultraviolet to near-infrared and an efficient gate tunability for photoresponse. Under bias, the phototransistor exhibits high responsivity of up to 1.42 × 10<jats:sup>3</jats:sup> A/W, and ultrahigh specific detectivity of up to 1.39 × 10<jats:sup>15</jats:sup> cmHz<jats:sup>1/2</jats:sup>W<jats:sup>-1</jats:sup>. Moreover, it can also operate under zero bias with remarkable responsivity of 10.2 A/W, relatively high specific detectivity of 1.43 × 10<jats:sup>14</jats:sup> cmHz<jats:sup>1/2</jats:sup>W<jats:sup>-1</jats:sup>, ultralow dark current of 1.22 fA, and high on/off ratio of above 105. These results should be attributed to the fact that the vertical HfSe<jats:sub>2</jats:sub>/MoS<jats:sub>2</jats:sub> heterostructure not only improves the broadband photoresponse of the phototransistor but also greatly enhances its sensitivity. Therefore, the heterostructure provides a promising candidate for next generation high performance phototransistors.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We theoretically studied thermoelectric transport properties through the triangular triple quantum dots (TTQD) structure in the linear response regime using the hierarchical equations of motion approach. We demonstrated that large See-beck coefficient was obtained when properly matching the interdot tunneling strength and magnetic flux at the electronhole symmetry point, as a result of spin chiral interactions in TTQD system. We presented a systematic investigation of the thermopower (the Seebeck coefficient) dependence on the tunneling strength, magnetic flux, and on-site energy. The Seebeck coefficient showed a clear breakdown of electron-hole symmetry in the vicinity of the Kondo regime, accompanied by the deviation from the semiclassical Mott relation in the Kondo and mixed-valence regimes, which resulted from the many-body effects of the Kondo correlated induced resonance together with spin chiral interactions.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>A scheme to improve the quality in ghost imaging (GI) by controlling the bandwidth of light source (BCGI) is proposed. The theoretical and numerical results show that the reconstruction result with high quality can be obtained by adjusting the bandwidth range of the light source appropriately, and the selection criteria of the bandwidth is analyzed by the power distribution of imaging target. A proof-of-principle experiment is implemented to verify the theoretical and numerical results. In addition, BCGI also presents better anti-noise performance when compared with some popular GI methods.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The binary CoSb<jats:sub>3</jats:sub> skutterudite thermoelectric material has high thermal conductivity due to the covalent bond between Co and Sb, and the thermoelectric figure of merit <jats:italic>ZT</jats:italic> is very low. The thermal conductivity of CoSb<jats:sub>3</jats:sub> materials can be significantly reduced through phonon engineering, such as low-dimensional structure, the introduction of nano second phases, nanointerfaces or nanopores, which greatly improves their <jats:italic>ZT</jats:italic> values. The phonon engineering can optimize significantly the thermal transport properties of CoSb<jats:sub>3</jats:sub>-based materials. However, the improvement of the electronic transport properties is not obvious, or even worse. Energy band and charge-carrier engineering can significantly improve the electronic transport properties of CoSb<jats:sub>3</jats:sub>-based materials while optimizing the thermal transport properties. Therefore, the decoupling of thermal and electronic transport properties of CoSb<jats:sub>3</jats:sub>-based materials can be realized by energy band and charge-carrier engineering. This review summarizes some methods of optimizing synergistically the electronic and thermal transport properties of CoSb<jats:sub>3</jats:sub> materials through the energy band and charge-carrier engineering strategies. Energy band engineering strategies include band convergence or resonant energy levels caused by doping/filling. The charge-carrier engineering strategy includes the optimization of carrier concentration and mobility caused by doping/filling, forming modulation doped structures or introducing nano second phase. These strategies are effective means to improve the performance of thermoelectric materials and provide new research ideas of the development of high-efficiency thermoelectric materials.</jats:p>