- 标题
- 摘要
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- 实验方案
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Systematic Optimation of Promoters in Trace SnS2 Coating SnO2 Nano-Heterostructure for High Performance Cr(VI) Photoreduction
摘要： Constructing heterojunction semiconductor materials with a strong interfacial interaction are emerging as a forefront material with excellent photocatalytic performance. Herein, we report a novel SnS2/SnO2 heterojunction material via in-situ trace vulcanization strategy to coating SnS2 on the SnO2. The thickness of the coating layer can be regulated by controlling the content of SnS2. Moreover, The molar ratio of S to Sn, particle size of SnO2 precursor and vulcanization time associated with the SnS2 content of heterojunction catalyst were controlled to optimize photocatalytic performance. SnS2/SnO2 heterojunction catalyst with 19.5% SnS2 content delivered a ultrahigh visible-light activity in Cr(VI) degradation, remarkably superior to the inert SnO2 precursors and full-vulcanized SnS2 under identical testing conditions. Amazingly, the enhanced interfacial interaction can remarkably enhance the separation and transfer of photogenerated charges. The systematic methodology of interface regulation in SnS2/SnO2 system is first reported in this work, which would promote the understanding of nano-heterojunction material for high-performance water treatment application.
关键词： Interfacial Interaction,Photovoltage,Photocatalyst,Nano-heterojunction,In-situ Vulcanization
更新于2025-09-09 09:28:46
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Reference Module in Chemistry, Molecular Sciences and Chemical Engineering || In or Out of Control? Electron Spin Polarization in Spin-Orbit-Influenced Systems
摘要： Spintronics is the key word to motivate studies of spin-polarized electronic states in solids and at surfaces or interfaces. The use of the electron spin in addition to the electron charge as information carrier—that is the goal for spintronics devices. The generation, manipulation, and detection of spin-polarized currents promise applications in information technology. However, in many materials, the electronic states are spin degenerate. The spin degeneracy may be lifted by two interactions: (i) exchange interaction in magnetically ordered materials, where the magnetization direction is the reference for the alignment of the spin magnetic moments. Independent of location and momentum, the electron spin magnetic moment is either aligned parallel to the magnetization direction (majority spin, lower in energy) or antiparallel to it (minority, higher in energy), leading to a spin-dependent energy splitting, called exchange splitting, of the bands; (ii) spin–orbit interaction (SOI), which is present in all materials but becomes relevant in systems with high atomic number. In ferromagnets, SOI enables hybridization between bands of different spin character, leading to spin–orbit-induced energy gaps, sometimes called spin hot spots in the band structure, which are held responsible for demagnetization processes. Furthermore, noncollinear magnetic structures such as skyrmions arise from SOI in ferromagnets. In nonferromagnets, SOI leads to energy splitting of bands with different total angular momentum j but not necessarily to spin-split bands. Only in systems, where inversion symmetry is broken, which is, for example, the case at surfaces, the bands exhibit a spin-dependent energy splitting, which itself depends on the momentum k. This so-called Rashba-type spin splitting was predicted for a two-dimensional electron gas and experimentally observed in surface states on heavy metal surfaces, for example, Au(111) and W(110). The spin-dependent splitting depends on the momentum parallel to the surface kk and reverses its sign upon a sign change of kk. As a consequence, no net magnetic moment is formed. In contrast to Rashba systems, where surface states become spin split by SOI, topological insulators such as Bi2Se3 exhibit so-called topological surface states (TSS), which only appear as a consequence of SOI. SOI is responsible for band inversion and formation of a gap, which is then closed by a surface state with Dirac-cone-like energy dispersion and characteristic spin texture.
关键词： Rashba-type spin splitting,Spin–orbit interaction,Dirac-cone-like energy dispersion,Topological surface state,Spintronics
更新于2025-09-09 09:28:46
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A novel and fast technique for evaluation of plastic rod scintillators as position sensitive gamma-ray detectors using artificial neural networks
摘要： The problem of how to precisely estimate the radiation interaction position is an important parameter in medical and industrial imaging systems. This paper presents a new methodology for prediction of the incident position of the gamma rays based attenuation technique and multilayer perceptron (MLP) neural network system. The detection system is comprised of a gamma-ray source (60Co or 137Cs) and a plastic rod scintillator (BC400) coupled with just one PMT at one side. The experimental setup provides the required data for training and testing the network. Using this proposed method, the radiation interaction position was predicted in plastic rod scintillator with a mean absolute error less than 0.8 and 0.5 for 137Cs and 60Co sources, respectively. The mean relative error percentage was calculated less than 3.9% and 3.5%. Also, the correlation coefficient was measured 0.999 and 0.998, respectively. The results showed that the predicted interaction position using the ANN method is in good agreement with real data. The techniques and set up used in the previous position sensitive detectors were fairly complicated whereas the new set-up and proposed method are really very simple. Also, the radiation safety, cost and shielding, and electronics requirements are minimized and optimized.
关键词： Plastic rod scintillator,Radiation interaction position,Artificial Neural Network,Position sensitive detector
更新于2025-09-09 09:28:46
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Fluorescent Metal-Semiconductor Hybrid Structures by Ultrasound-Assisted In-Situ Growth of Gold Nanoparticles on Silica-Coated CdSe-Dot/CdS-Rod Nanocrystals
摘要： Gold nanocrystals (AuNCs) were grown on the surface of silica coated CdSe-dot/CdS-rod core/shell nanocrystals by reduction of Au3+ ions in polyethylene glycol under ultrasonic irradiation. The polyethylene glycol not only prevents the penetration of gold ions or precursor molecules into the silica shell, but it also acts as the reducing agent for Au3+ ions. The silica shell’s surface promotes the heterogeneous nucleation of gold nanocrystals, while the ultrasonic irradiation accelerates and enhances the gold nucleation on the silica surface, and ensures the formation of AuNCs with a relatively narrow size distribution. The plasmon-exciton interaction in these metal-semiconductor hybrid systems leads to decreased fluorescence lifetimes and strongly reduced fluorescence blinking of individual hybrid structures.
关键词： ultrasonic irradiation,Gold nanocrystals,CdSe-dot/CdS-rod nanocrystals,plasmon-exciton interaction,polyethylene glycol
更新于2025-09-09 09:28:46
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Diffractive scattering: problems in theory and practice
摘要： We give a retrospective overview of the conceptual content of the strong interaction scattering at high energies with account of the latest experimental findings made at the LHC.
关键词： high energies,strong interaction,Standard Model,diffractive scattering,LHC
更新于2025-09-09 09:28:46
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Direct interaction along light cones at the quantum level
摘要： Here, we point out that interactions with time delay can be described at the quantum level using a multi-time wave function ψ(x1, ..., xN), i.e. a wave function depending on one spacetime variable xi = (ti, xi) per particle. In particular, such a wave function makes it possible to implement direct interaction along light cones (not mediated by fields), as in the Wheeler–Feynman formulation of electrodynamics. Our results are as follows. (1) We derive a covariant two-particle integral equation and discuss it in detail. (2) It is shown how this integral equation (or equivalently, a system of two integro-differential equations) can be understood as defining the time evolution of ψ in a consistent way. (3) We demonstrate that the equation has strong analogies with Wheeler–Feynman electrodynamics and therefore suggests a possible new quantization of that theory. (4) We propose two natural ways how the two-particle equation can be extended to N particles. It is shown that exactly one of them leads to the usual Schr?dinger equation with Coulomb-type pair potentials if time delay effects are neglected.
关键词： quantization of Wheeler–Feynman electrodynamics,integral equations,relativistic quantum theory,integro-differential equations,interaction with time delay,multi-time wave functions,Bethe–Salpeter equation
更新于2025-09-09 09:28:46
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Conditions for optical parametric oscillation with a structured light pump
摘要： We investigate the transverse mode structure of the down-converted beams generated by a type-II optical parametric oscillator (OPO) driven by a structured pump. Our analysis focuses on the selection rules imposed by the spatial overlap between the transverse modes of the three fields involved in the nonlinear interaction. These rules imply a hierarchy of oscillation thresholds that determine the possible transverse modes generated by the OPO, as remarkably confirmed with experimental results.
关键词： structured pump,transverse mode structure,optical parametric oscillator,nonlinear interaction,oscillation thresholds
更新于2025-09-09 09:28:46
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Design of Dual-Band Bandpass Filter With Multiple Transmission Zeros Using Transversal Signal Interaction Concepts
摘要： In this letter, a compact dual-band bandpass ?lter (BPF) based on the transversal signal interaction concepts is presented. The center frequencies of dual-band BPF are centered at 3.8 and 4.8 GHz with 3-dB fraction bandwidths of 11.3% and 10.7%, respectively. Transversal ?ltering structure is introduced in the proposed dual-band BPF, which provides two signal propagation paths from input to output. Thus, a dozen of transmission zeros are yielded to obtain wide stopband suppression ranging from 5.2 to 16 GHz. To validate the design scheme, a dual-band BPF with high selectivity, compact size, independently controllable bandwidth, and wide stopband suppression is fabricated and measured.
关键词： Bandpass ?lter (BPF),transmission zeros,dual band,transversal signal interaction (TSI)
更新于2025-09-09 09:28:46
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The Correlation between the Energy Gap and the Pseudogap Temperature in Cuprates: The YCBCZO and LSHCO Case
摘要： The paper analyzes the influence of the hole density, the out-of-plane or in-plane disorder, and the isotopic oxygen mass on the zero temperature energy gap (2Δ(0)) Y1???Ca??Ba2(Cu1???Zn??)3O7??? (YCBCZO) and La1.96???Sr??Ho0.04CuO4 (LSHCO) superconductors. It has been found that the energy gap is visibly correlated with the value of the pseudogap temperature (???). On the other hand, no correlation between 2Δ(0) and the critical temperature (????) has been found. The above results mean that the value of the dimensionless ratio 2Δ(0)/???????? can vary very strongly together with the chemical composition, while the parameter 2Δ(0)/??????? does not change significantly. In the paper, the analytical formula which binds the zero temperature energy gap and the pseudogap temperature has been also presented.
关键词： energy gap,pseudogap temperature,superconductors,cuprates,electron-phonon interaction,electron-electron correlations
更新于2025-09-09 09:28:46
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Two-photon self-Kerr nonlinearities for quantum computing and quantum optics
摘要： The self-Kerr interaction is an optical nonlinearity that produces a phase shift proportional to the square of the number of photons in the field. At present, many proposals use nonlinearities to generate photon-photon interactions. For propagating fields these interactions result in undesirable features such as spectral correlation between the photons. Here we engineer a discrete network composed of cross-Kerr interaction regions to simulate a self-Kerr medium. The medium has effective long-range interactions implemented in a physically local way. We compute the one- and two-photon S matrices for fields propagating in this medium. From these scattering matrices we show that our proposal leads to a high-fidelity photon-photon gate. In the limit where the number of nodes in the network tends to infinity, the medium approximates a perfect self-Kerr interaction in the one- and two-photon regime.
关键词： quantum computing,quantum optics,photon-photon gate,cross-Kerr interaction,self-Kerr interaction
更新于2025-09-04 15:30:14