Theoretical research on the transverse spin of structured optical fields inside a waveguide

Structured optical fields inside a waveguide possess the transverse spin, i.e., the spin angular momentum perpendicular to the direction of the waveguide. The physical origin of the transverse spin can be attributed to the presence of an effective rest mass of photons in guided waves, or equivalently, to the existence of a longitudinal field component, such that the transverse and longitudinal fields together form an elliptical polarization plane. In contrary to the traditional viewpoint, the transverse spin of photons in guided waves is also quantized, and its quantization form is related to the ellipticity of the polarization ellipse. The direction of the transverse spin depends on the propagation direction of electromagnetic waves along the waveguide, such a spin-momentum locking may have important applications in spin-dependent unidirectional optical interfaces. By means of a coupling between the transverse spin of guided waves and some physical degrees of freedom, one can develop an optical analogy of spintronics, i.e., spinoptics.

Establish and Highlight the Chinese Cultural Symbols and the Image of the Chinese Nation Shared by All Ethnic Groups

Establishing and highlighting Chinese cultural symbols and the image of the Chinese nation shared by all ethnic groups is necessary to foster a sense of community for the Chinese nation and to comprehensively build a modern socialist state.The article explains the understanding of the connotation of establishing and highlighting Chinese cultural symbols and the image of the Chinese nation shared by all ethnic groups,analyzes the practical problems in its practice,and proposes to strengthen Chinese cultural integration and national narratives,build a new era cultural symbol system led by the core socialist values,and creatively transform and innovatively develop Chinese cultural symbols and the image of the Chinese nation shared by all ethnic groups.

On-chip spiking neural networks based on add-drop ring microresonators and electrically reconfigurable phase-change material photonic switches

We propose and numerically demonstrate a photonic computing primitive designed for integrated spiking neural networks (SNNs) based on add-drop ring microresonators (ADRMRs) and electrically reconfigurable phasechange material (PCM) photonic switches. In this neuromorphic system, the passive silicon-based ADRMR,equipped with a power-tunable auxiliary light, effectively demonstrates nonlinearity-induced dual neural dynamics encompassing spiking response and synaptic plasticity that can generate single-wavelength optical neural spikes with synaptic weight. By cascading these ADRMRs with different resonant wavelengths, weighted multiple-wavelength spikes can be feasibly output from the ADRMR-based hardware arrays when external wavelengthaddressable optical pulses are injected;subsequently, the cumulative power of these weighted output spikes is utilized to ascertain the activation status of the reconfigurable PCM photonic switches. Moreover, the reconfigurable mechanism driving the interconversion of the PCMs between the resonant-bonded crystalline states and the covalent-bonded amorphous states is achieved through precise thermal modulation. Drawing from the thermal properties, an innovative thermodynamic leaky integrate-and-firing (TLIF) neuron system is proposed. With the TLIF neuron system as the fundamental unit, a fully connected SNN is constructed to complete a classic deep learning task:the recognition of handwritten digit patterns. The simulation results reveal that the exemplary SNN can effectively recognize 10 numbers directly in the optical domain by employing the surrogate gradient algorithm. The theoretical verification of our architecture paves a whole new path for integrated photonic SNNs, with the potential to advance the field of neuromorphic photonic systems and enable more efficient spiking information processing.

Multiplicity of nontrivial solutions for Kirchhoff type equations with zero mass and a critical term

In this paper,a class of Kirchhoff type equations in R^(N)(N≥3)with zero mass and a critical term is studied.Under some appropriate conditions,the existence of multiple solutions is obtained by using variational methods and a variant of Symmetric Mountain Pass theorem.The Second Concentration Compactness lemma is used to overcome the lack of compactness in critical problem.Compared to the usual Kirchhoff-type problems,we only require the nonlinearity to satisfy the classical superquadratic condition(Ambrosetti-Rabinowitz condition).

非晶Cu2MoS4纳米笼的形貌和结构工程用于高效电解水产氢（英文）

非晶纳米材料因长程无序的原子排列,其形貌和结构的调控极具挑战性.本文首次报道了一种可控自水解蚀刻-沉淀(SHEP)法,在常温常压下即可合成出空心多孔且形貌规则的非晶Cu2MoS4纳米笼(a-Cu2MoS4).得益于其空心多孔结构和非晶的丰富硫缺陷,a-CsMoS,表现出比晶体相对物更强的析氢反应(HER)活性.其中,壳厚度为20nm的八面体a-Cu2MoS4表现出最好的HER活性:在10mAcm^-2电流密度下,过电位仅为96mV,塔菲尔斜率低至61mVdecade^-1;这主要是因为a-Cu2MoS4合适的厚度既保证了其表面的多孔性,又确保了其结构的稳定性.本文提出的合成方法具有普适性,可扩展到更多的三元纳米笼材料的合成,为各种三元纳米笼的精确可控制备提供了新视角,并为开发高活性非晶催化剂开辟了新的途径.

Two-dimensional transition metal chalcogenide nanomaterials for cancer diagnosis and treatment

For more than a decade,the exfoliation of graphene and other layered materials has led to a tremendous amount of research in two-dimensional(2D)materials,among which 2D transition metal chalcogenides(TMCs)nanomaterials have attracted much attention in a wide range of applications including photoelectric devices,lithium-ion batteries,catalysis,and energy conversion and storage owing to their unique photoelectric physical properties.With such large specific surface area,strong near-infrared(NIR)absorption and abundant chemical element composition,2D TMCs nanomaterials have become good candidates in biomedical imaging and cancer treatment.This review systematically summarizes recent progress on 2D TMCs nanomaterials,which includes their synthesis methods and applications in cancer treatment.At the end of this review,we also highlight the future prospects and challenges of 2D TMCs nanomaterials.It is expected that this work can provide the readers with a detailed overview of the synthesis of 2D TMCs and inspire more novel functional biomaterials based on 2D TMCs for cancer treatment in the future.