Photonic hardware implementation of spiking neural networks,regarded as a viable potential paradigm for ultra-high speed and energy efficiency computing,leverages spatiotemporal spike encoding and event-driven dynamic...Photonic hardware implementation of spiking neural networks,regarded as a viable potential paradigm for ultra-high speed and energy efficiency computing,leverages spatiotemporal spike encoding and event-driven dynamics to simulate brain-like parallel information processing.Silicon-based microring resonators(MRRs)offer a power efficiency and ultrahigh flexibility scheme to mimic biological neuron,however,their substantial potential for integrated neuromorphic systems remains limited by insufficient exploration of MRR-based spiking digital and analog computation.Here,an all-optical neural dynamics framework,encompassing both excitatory and inhibitory behaviors based on multi-wavelength auxiliary and competition mechanism in an MRR,is proposed numerically.Leveraging multi-wavelength resonance characteristics and wavelength division multiplexing(WDM)technology,a single MRR implements the five fundamental optical digital logic gates:AND,OR,NOT,XNOR and XOR.Besides,the cascading capabilities of MRR-based spiking neurons are demonstrated through multi-level digital logic gates including NAND,NOR,4-input AND,8-input AND,and a full adder,emphasizing their promise for large-scale digital logic networks.Furthermore,an exemplary binary convolution has been achieved by utilizing the proposed MRR-based digital logic operation,illustrating the potential of all-optical binary convolution to compute image gradient magnitudes for edge detection.Such passive photonic neurons and networks promise access to the high transmission speed and low power consumption inherent to optical systems,thus enabling direct hardware-algorithm co-computation and accelerating artificial intelligence.展开更多
In this article, a finite volume element algorithm is presented and discussed for the numerical solutions of a time-fractional nonlinear fourth-order diffusion equation with time delay. By choosing the second-order sp...In this article, a finite volume element algorithm is presented and discussed for the numerical solutions of a time-fractional nonlinear fourth-order diffusion equation with time delay. By choosing the second-order spatial derivative of the original unknown as an additional variable, the fourth-order problem is transformed into a second-order system. Then the fully discrete finite volume element scheme is formulated by using L1approximation for temporal Caputo derivative and finite volume element method in spatial direction. The unique solvability and stable result of the proposed scheme are proved. A priori estimate of L2-norm with optimal order of convergence O(h2+τ2−α)where τand hare time step length and space mesh parameter, respectively, is obtained. The efficiency of the scheme is supported by some numerical experiments.展开更多
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)nanomaterial...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.展开更多
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 t...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.展开更多
Developing novel nanoparticle-based bioprobes utilized in clinical settings with imaging resolutions ranging from cell to tissue levels is a major challenge for tumor diagnosis and treatment.Herein,an optimized strate...Developing novel nanoparticle-based bioprobes utilized in clinical settings with imaging resolutions ranging from cell to tissue levels is a major challenge for tumor diagnosis and treatment.Herein,an optimized strategy for designing a Fe_(3)O_(4)-based bioprobe for dual-modal cancer imaging based on surface-enhanced Raman scattering(SERS)and magnetic resonance imaging(MRI)is introduced.Excellent SERS activity of ultrasmall Fe_(3)O_(4) nanoparticles(NPs)was discovered,and a 5×10^(-9)M limit of detection for crystal violet molecules was successfully obtained.The high-efficiency interfacial photon-induced charge transfer in Fe_(3)O_(4) NPs was promoted by multiple electronic energy levels ascribed to the multiple valence states of Fe,which was observed using ultraviolet-visible diffuse reflectance spectroscopy.Density functional theory calculations were utilized to reveal that the narrow band gap and high electron density of states of ultrasmall Fe_(3)O_(4) NPs significantly boosted the vibronic coupling resonances in the SERS system upon illumination.The subtypes of cancer cells were accurately recognized via high-resolution SERS imaging in vitro using the prepared Feg Og-based bioprobe with high sensitivity and good specificity.Notably,Fe_(3)O_(4)-based bioprobes simultaneously exhibited T,-weighted MRI contrast enhancement with an active targeting capability for tumors in vivo.To the best of our knowledge,this is the first report on the use of pure semiconductor-based SERS-MRI dual-modal nanoprobes in tumor imaging in vivo and in vitro,which has been previously realized only using semiconductor-metal complex materials.The non-metallic materials with SERS-MRI dual-modal imaging established in this report are a promising cancer diagnostic platform,which not only showed excellent performance in early tumor diagnosis but also possesses great potential for image-guided tumor treatment.展开更多
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 meth...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).展开更多
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 ...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.展开更多
Surface-enhanced Raman scattering(SERS)is a non-invasive spectroscopic technique that provides specific chemical fingerprint information for biomarkers in cancer and pathogen diagnosis.However,the SERS strategies are ...Surface-enhanced Raman scattering(SERS)is a non-invasive spectroscopic technique that provides specific chemical fingerprint information for biomarkers in cancer and pathogen diagnosis.However,the SERS strategies are limited by the non-specific interactions between substrates and co-existing substances in biological matrices and the challenges of obtaining molecular fingerprint information from the complex vibrational spectrum.In recent years,the rapid development of novel substrates with high SERS activity has opened up new opportunities for their applications in cancer and pathogen diagnosis.The aim of this review is to present the recent progress and perspectives of novel SERS-based substrates for cancer and pathogen diagnostic applications.First,we will introduce recently developed SERS-active nanomaterials and discuss the influencing factors of the SERS signals.Second,the advantages of SERS in the diagnosis of cancer and pathogens will be given.Third,we will review the latest breakthroughs in cancer and pathogen detection research with SERS technology,as well as the new opportunities for SERS applications brought about by artificial intelligence(Al)technology.In addition,the novel microfluidic-SERS platforms for cancer and pathogens diagnosis will also be discussed.Finally,we will summarize the challenges and future perspectives of SERS technology in the field of early cancer diagnosis and rapid pathogen detection.It is highly expected that this review could benefit a comprehensive understanding of the research status of the SERS-active nanomaterials and arouse the research enthusiasm for them,leading to accelerated clinical translation of SERS technology in cancer and pathogen diagnosis.展开更多
Finding more specific subcategories within a larger category is the goal of fine-grained image classification(FGIC),and the key is to find local discriminative regions of visual features.Most existing methods use trad...Finding more specific subcategories within a larger category is the goal of fine-grained image classification(FGIC),and the key is to find local discriminative regions of visual features.Most existing methods use traditional convolutional operations to achieve fine-grained image classification.However,traditional convolution cannot extract multi-scale features of an image and existing methods are susceptible to interference from image background information.Therefore,to address the above problems,this paper proposes an FGIC model(Attention-PCNN)based on hybrid attention mechanism and pyramidal convolution.The model feeds the multi-scale features extracted by the pyramidal convolutional neural network into two branches capturing global and local information respectively.In particular,a hybrid attention mechanism is added to the branch capturing global information in order to reduce the interference of image background information and make the model pay more attention to the target region with fine-grained features.In addition,the mutual-channel loss(MC-LOSS)is introduced in the local information branch to capture fine-grained features.We evaluated the model on three publicly available datasets CUB-200-2011,Stanford Cars,FGVCAircraft,etc.Compared to the state-of-the-art methods,the results show that Attention-PCNN performs better.展开更多
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 ...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.展开更多
Morphological and structural control of amorphous nanomaterials is challenging due to the long-range disordered atomic arrangements. Herein, we firstly propose a controllable self-hydrolyzing etching-precipitating (SH...Morphological and structural control of amorphous nanomaterials is challenging due to the long-range disordered atomic arrangements. Herein, we firstly propose a controllable self-hydrolyzing etching-precipitating (SHEP) method to fabricate the regular-shaped amorphous Cu2MoS4 nanocages (a-Cu2MoS4 NCs) with hollow porous structures under ambient conditions. Benefitting from the hollow porous structures and the amorphous characteristics with copious sulfur vacancies, the a-Cu2MoS4 NCs possess more enhanced activity toward hydrogen evolution reaction (HER) than their crystalline counterparts. The octahedral a-Cu2MoS4 NCs with a shell thickness of 20 nm, which balance the appropriate surface porosity and good structural stability, exhibit the best HER activity with a low overpotential of 96 mV at 10 mA cm^-2 and a small tafel slope of 61 mV decade^-1 in alkaline environment. Moreover, this method is very versatile and can be extended to synthesize other ternary nanocages. Our current work may shed light on the precise controllable synthesis of various ternary nanocages and open a new frontier for developing highly active amorphous catalysts.展开更多
基金supports from National Natural Science Foundation of China(62171087,62475036).
文摘Photonic hardware implementation of spiking neural networks,regarded as a viable potential paradigm for ultra-high speed and energy efficiency computing,leverages spatiotemporal spike encoding and event-driven dynamics to simulate brain-like parallel information processing.Silicon-based microring resonators(MRRs)offer a power efficiency and ultrahigh flexibility scheme to mimic biological neuron,however,their substantial potential for integrated neuromorphic systems remains limited by insufficient exploration of MRR-based spiking digital and analog computation.Here,an all-optical neural dynamics framework,encompassing both excitatory and inhibitory behaviors based on multi-wavelength auxiliary and competition mechanism in an MRR,is proposed numerically.Leveraging multi-wavelength resonance characteristics and wavelength division multiplexing(WDM)technology,a single MRR implements the five fundamental optical digital logic gates:AND,OR,NOT,XNOR and XOR.Besides,the cascading capabilities of MRR-based spiking neurons are demonstrated through multi-level digital logic gates including NAND,NOR,4-input AND,8-input AND,and a full adder,emphasizing their promise for large-scale digital logic networks.Furthermore,an exemplary binary convolution has been achieved by utilizing the proposed MRR-based digital logic operation,illustrating the potential of all-optical binary convolution to compute image gradient magnitudes for edge detection.Such passive photonic neurons and networks promise access to the high transmission speed and low power consumption inherent to optical systems,thus enabling direct hardware-algorithm co-computation and accelerating artificial intelligence.
文摘In this article, a finite volume element algorithm is presented and discussed for the numerical solutions of a time-fractional nonlinear fourth-order diffusion equation with time delay. By choosing the second-order spatial derivative of the original unknown as an additional variable, the fourth-order problem is transformed into a second-order system. Then the fully discrete finite volume element scheme is formulated by using L1approximation for temporal Caputo derivative and finite volume element method in spatial direction. The unique solvability and stable result of the proposed scheme are proved. A priori estimate of L2-norm with optimal order of convergence O(h2+τ2−α)where τand hare time step length and space mesh parameter, respectively, is obtained. The efficiency of the scheme is supported by some numerical experiments.
基金supported by the National Natural Science Foundationof China(NSFC,Nos.21971007,21521005,51902012)Beijing Natural Science Foundation(No.2212044)the Fundamental Research Funds for the Central Universities(Nos.XK1802-6,XK1803-05)。
文摘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.
基金Project supported by the 2021 Innovation capability enhancement project of small and medium-sized technologybased enterprises in Shandong Province of China (Grant No. 2021TSGC1043)。
文摘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.
文摘Developing novel nanoparticle-based bioprobes utilized in clinical settings with imaging resolutions ranging from cell to tissue levels is a major challenge for tumor diagnosis and treatment.Herein,an optimized strategy for designing a Fe_(3)O_(4)-based bioprobe for dual-modal cancer imaging based on surface-enhanced Raman scattering(SERS)and magnetic resonance imaging(MRI)is introduced.Excellent SERS activity of ultrasmall Fe_(3)O_(4) nanoparticles(NPs)was discovered,and a 5×10^(-9)M limit of detection for crystal violet molecules was successfully obtained.The high-efficiency interfacial photon-induced charge transfer in Fe_(3)O_(4) NPs was promoted by multiple electronic energy levels ascribed to the multiple valence states of Fe,which was observed using ultraviolet-visible diffuse reflectance spectroscopy.Density functional theory calculations were utilized to reveal that the narrow band gap and high electron density of states of ultrasmall Fe_(3)O_(4) NPs significantly boosted the vibronic coupling resonances in the SERS system upon illumination.The subtypes of cancer cells were accurately recognized via high-resolution SERS imaging in vitro using the prepared Feg Og-based bioprobe with high sensitivity and good specificity.Notably,Fe_(3)O_(4)-based bioprobes simultaneously exhibited T,-weighted MRI contrast enhancement with an active targeting capability for tumors in vivo.To the best of our knowledge,this is the first report on the use of pure semiconductor-based SERS-MRI dual-modal nanoprobes in tumor imaging in vivo and in vitro,which has been previously realized only using semiconductor-metal complex materials.The non-metallic materials with SERS-MRI dual-modal imaging established in this report are a promising cancer diagnostic platform,which not only showed excellent performance in early tumor diagnosis but also possesses great potential for image-guided tumor treatment.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.11701346,11671239,11801338)the Natural Science Foundation of Shanxi Province(Grant No.201801D211001)+1 种基金the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(Grant No.2019L0024)the Research Project Supported by Shanxi Scholarship Council of China(Grant No.2020-005).
文摘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).
基金This paper is the result of a major project of the National Social Science Foundation(21VMZ001)on"Research on General Secretary Xi Jinping's Important Discourse on Forging the Consciousness of the Chinese National Community"and a major project of the Minzu University of China(2021)on"Forging the Consciousness of the Chinese National Community"."The research results of the major project""Research on the connotation,logic and structure of forging a sense of Chinese national community"(2021MDZL02)of the Central University for Nationalities.
文摘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.
基金This work was supported by National Natural Science Foundation of China(Nos.62401053 and 12374390)the Fundamental Research Funds for the Central Universities,the member of Youth Innovation Promotion Association Foundation of CAS,China(No.2023310)the Key Scientific and Technological Special Project of Ningbo City(No.2023Z209).
文摘Surface-enhanced Raman scattering(SERS)is a non-invasive spectroscopic technique that provides specific chemical fingerprint information for biomarkers in cancer and pathogen diagnosis.However,the SERS strategies are limited by the non-specific interactions between substrates and co-existing substances in biological matrices and the challenges of obtaining molecular fingerprint information from the complex vibrational spectrum.In recent years,the rapid development of novel substrates with high SERS activity has opened up new opportunities for their applications in cancer and pathogen diagnosis.The aim of this review is to present the recent progress and perspectives of novel SERS-based substrates for cancer and pathogen diagnostic applications.First,we will introduce recently developed SERS-active nanomaterials and discuss the influencing factors of the SERS signals.Second,the advantages of SERS in the diagnosis of cancer and pathogens will be given.Third,we will review the latest breakthroughs in cancer and pathogen detection research with SERS technology,as well as the new opportunities for SERS applications brought about by artificial intelligence(Al)technology.In addition,the novel microfluidic-SERS platforms for cancer and pathogens diagnosis will also be discussed.Finally,we will summarize the challenges and future perspectives of SERS technology in the field of early cancer diagnosis and rapid pathogen detection.It is highly expected that this review could benefit a comprehensive understanding of the research status of the SERS-active nanomaterials and arouse the research enthusiasm for them,leading to accelerated clinical translation of SERS technology in cancer and pathogen diagnosis.
基金supported by the National Natural Science Foundation of China(Nos.62372266,61832012,12271295,and 62072273)the Natural Science Foundation of Shandong Province(Nos.ZR2020MF149,ZR2022MF304,ZR2021MF075,ZR2021QF050,and ZR2019ZD10)the Key Research and Development Program Project of Shandong Province(No.2022CXPT055).
文摘Finding more specific subcategories within a larger category is the goal of fine-grained image classification(FGIC),and the key is to find local discriminative regions of visual features.Most existing methods use traditional convolutional operations to achieve fine-grained image classification.However,traditional convolution cannot extract multi-scale features of an image and existing methods are susceptible to interference from image background information.Therefore,to address the above problems,this paper proposes an FGIC model(Attention-PCNN)based on hybrid attention mechanism and pyramidal convolution.The model feeds the multi-scale features extracted by the pyramidal convolutional neural network into two branches capturing global and local information respectively.In particular,a hybrid attention mechanism is added to the branch capturing global information in order to reduce the interference of image background information and make the model pay more attention to the target region with fine-grained features.In addition,the mutual-channel loss(MC-LOSS)is introduced in the local information branch to capture fine-grained features.We evaluated the model on three publicly available datasets CUB-200-2011,Stanford Cars,FGVCAircraft,etc.Compared to the state-of-the-art methods,the results show that Attention-PCNN performs better.
基金National Natural Science Foundation of China(62171087)Sichuan Science and Technology Program(2021JDJQ0023)Fundamental Research Funds for the Central Universities (ZYGX2019J003)。
文摘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.
基金financially supported by the National Natural Science Foundation of China(51532001)
文摘Morphological and structural control of amorphous nanomaterials is challenging due to the long-range disordered atomic arrangements. Herein, we firstly propose a controllable self-hydrolyzing etching-precipitating (SHEP) method to fabricate the regular-shaped amorphous Cu2MoS4 nanocages (a-Cu2MoS4 NCs) with hollow porous structures under ambient conditions. Benefitting from the hollow porous structures and the amorphous characteristics with copious sulfur vacancies, the a-Cu2MoS4 NCs possess more enhanced activity toward hydrogen evolution reaction (HER) than their crystalline counterparts. The octahedral a-Cu2MoS4 NCs with a shell thickness of 20 nm, which balance the appropriate surface porosity and good structural stability, exhibit the best HER activity with a low overpotential of 96 mV at 10 mA cm^-2 and a small tafel slope of 61 mV decade^-1 in alkaline environment. Moreover, this method is very versatile and can be extended to synthesize other ternary nanocages. Our current work may shed light on the precise controllable synthesis of various ternary nanocages and open a new frontier for developing highly active amorphous catalysts.
