- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Welding of Dissimilar Steel/Al Joints Using Dual-Beam Lasers with Side-by-Side Configuration
摘要： Welding of dissimilar steel/Al lapped joints of 1.5 mm in thickness was carried out by using dual-beam laser welding with side-by-side configuration. The effect of the major process parameters including the dual-beam power ratio of (Rs) and dual-beam distance (d1) on the steel/Al joint characteristics was investigated concerning the weld shape, interface microstructures, tensile resistance and fracture behavior. The results show that dual-beam laser welding with side-by-side configuration produces soundly welded steel/Al lapped joints free of welding defects. The processing parameters of Rs and d1 have a great influence on the weld appearance, the weld penetration in the Al alloy side (P2) and the welding defects. Variation in the depth of the P2 and the locations at the Al/weld interface cause heterogeneous microstructures in the morphology and the thickness of the intermetallic compound (IMC) layers. In addition, electron back scattered diffraction (EBSD) phase mapping reveals that the IMC layer microstructures formed at the Al/weld interface include the needle-like θ-Fe4Al13 phases and compact lath η-Fe2Al5 layers. Some very fine θ-Fe4Al13 and η-Fe2Al5 phases generated along the weld grain boundaries of the steel/Al joints are also confirmed. Finally, there is a matching relationship between the P2 and the tensile resistance of steel/Al joints, and the maximum tensile resistance of 109.2 N/mm is obtained by the steel/Al joints produced at the Rs of 1.50 during dual-beam laser welding with side-by-side configuration. Two fracture path modes have taken place depending on the P2, and relatively high resistance has been achieved for the steel/Al joints with an optimum P2.
关键词： dual-beam laser welding,tensile resistance,side-by-side configuration,EBSD phase mapping,steel/Al joint
更新于2025-11-28 14:24:20
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Analysis of trajectory similarity and configuration similarity in on-the-fly surface-hopping simulation on multi-channel nonadiabatic photoisomerization dynamics
摘要： We propose an “automatic” approach to analyze the results of the on-the-fly trajectory surface hopping simulation on the multi-channel nonadiabatic photoisomerization dynamics by considering the trajectory similarity and the configuration similarity. We choose a representative system phytochromobilin (PΦB) chromophore model to illustrate the analysis protocol. After a large number of trajectories are obtained, it is possible to define the similarity of different trajectories by the Fréchet distance and to employ the trajectory clustering analysis to divide all trajectories into several clusters. Each cluster in principle represents a photoinduced isomerization reaction channel. This idea provides an effective approach to understand the branching ratio of the multi-channel photoisomerization dynamics. For each cluster, the dimensionality reduction is employed to understand the configuration similarity in the trajectory propagation, which provides the understanding of the major geometry evolution features in each reaction channel. The results show that this analysis protocol not only assigns all trajectories into different photoisomerization reaction channels but also extracts the major molecular motion without the requirement of the pre-known knowledge of the active photoisomerization site. As a side product of this analysis tool, it is also easy to find the so-called “typical” or “representative” trajectory for each reaction channel.
关键词： trajectory similarity,multi-channel nonadiabatic photoisomerization dynamics,Fréchet distance,dimensionality reduction,phytochromobilin chromophore,on-the-fly surface-hopping simulation,configuration similarity,clustering analysis
更新于2025-09-23 15:23:52
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A Novel Actuator-Internal Micro/Nano Positioning Stage with an Arch-Shape Bridge Type Amplifier
摘要： This paper presents a novel actuator-internal two degree-of-freedom (2-DOF) micro/nano positioning stage actuated by piezoelectric (PZT) actuators, which can be used as a fine actuation part in dual-stage system. To compensate the positioning error of coarse stage and achieve a large motion stroke, a symmetrical structure with an arch-shape bridge type amplifier based on single notch circular flexure hinges is proposed and utilized in the positioning stage. Due to the compound bridge arm configuration and compact flexure hinge structure, the amplification mechanism can realize high lateral stiffness and compact structure simultaneously, which is of great importance to protect PZT actuators. The amplification mechanism is integrated into the decoupling mechanism to improve compactness, and to produce decoupled motion in X- and Y- axes. An analytical model is established to explore the static and dynamic characteristics, and the geometric parameters are optimized. The performance of the positioning stage is evaluated through finite element analysis (FEA) and experimental test. The results indicate that the stage can implement 2-DOF decoupled motion with a travel range of 55.4×53.2 μm2, and the motion resolution is 8 nm. The stage can be used in probe tip-based micro/nano scratching.
关键词： Decoupling mechanism,Micro/nano positioning,Actuator-internal configuration,Arch-shape bridge type amplifier
更新于2025-09-23 15:23:52
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Optical memory characteristics of solution-processed organic transistors with self-organized organic floating gates for printable multi-level storage devices
摘要： Exploring optical memory functions in nonvolatile organic field-effect transistor (OFET) memories with top-gate/bottom-contact (TG/BC) configurations can offer effective routes for developing printable, high-density organic memory circuits capable of multi-level data storage. Here, we use a solution process to fabricate TG/BC OFET devices with organic floating-gate structures and investigate their memory characteristics under light illumination. A solution-processable organic composite of 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) and poly(methylmethacrylate) is employed to self-organize organic floating-gate structures on a solution-processed semiconductor layer composed of poly(3-hexylthiophene) (P3HT). The floating-gate OFET devices programmed with blue, green, and red light exhibit large threshold voltage (Vth) shifts of approximately 30 V and stable charge retention characteristics even under light illumination. The devices also exhibit high sensitivity to incident light during programming, and the degree of Vth shift and the on-state current can be tuned using light and programming voltage to facilitate distinct storage and readout of multi-level data.
关键词： floating-gate memory,organic field-effect transistor,top-gate/bottom-contact configuration,multi-level data storage,solution-processable organic material
更新于2025-09-23 15:23:52
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How doping configuration affects electron transport in monolayer zigzag graphene nanoribbon
摘要： The electrical conductance of hybrid monolayer graphene/h-BN ribbon with zigzag edges is numerically investigated using density functional theory. Our findings reveal that transmission of graphene/h-BN hybrid structure is sensitive to the arrangement of its component. The result also shows that replacing carbon atoms with boron and nitrogen totally reduces the transmission. Three different arrangement of BN domains have been investigated: replacing carbon atoms with boron and nitrogen in the transport direction, perpendicular to the transport direction and diagonal direction. We find that combination of many factors such as edge effect, additional charge carrier, interface of BN and carbon domains can alter transmission significantly.
关键词： Density functional theory,Doping configuration,Graphene/h-BN hybrid,Electronic transport
更新于2025-09-23 15:23:52
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Enhanced Photocatalytic Activity by the Combined Influence of Ferroelectric Domain and Au Nanoparticles for BaTiO <sub/>3</sub> Fibers
摘要： Ferroelectric particles have been applied in the photocatalytic field because the spontaneous polarization results in the internal electric field, which can accelerate the separation and migration of photogenerated carriers. In this study, the BaTiO3 (BT) fibers are synthesized by electrospinning. The BT fibers calcined above 800 °C exhibit a strong ferroelectric property, which is verified by a typical butterfly-shaped displacement-voltage loop. It is found that the BT fibers with the single-domain structure exhibit better photocatalytic performance than that with the multi-domain configuration. When the single-domain transforms into multi-domain, the integrated internal electric field correspondingly breaks up, inducing that the internal electric field might cancel each other out and diminish the separation of photogenerated carriers. Also, the Au nanoparticles can improve the photocatalytic activity further on account of the surface plasmon resonance. Therefore, it is suggested that Au nanoparticles decorated on ferroelectric BT nanomaterials are promising photocatalysts.
关键词： photocatalytic performance,Ferroelectric property,domain configuration,internal electric field
更新于2025-09-23 15:23:52
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A Simplified Approach for Obtaining Optical Properties of VO <sub/>2</sub> Thin Films, and Demonstration of Infrared Shape-Shifting Devices
摘要： Micrometer-sized VO2-based devices with integrated resistive heaters of different configurations are fabricated. Quality of the VO2 films is confirmed by measuring the characteristic drop in transmittance and negative differential emissivity for these films. A two-interface model for optical transmittance, reflectance, and absorbance is presented. This method and analytic model presents an advantage over most typically used approaches in that it does not require direct measurements of the material’s optical constants to estimate transmittance. By combining the substrate and the VO2 film into one layer with a reduced optical admittance, the two-interface model is reduced to a single-layer model. Moreover, the present work demonstrates the implementation of the developed VO2-based devices in adaptive camouflage and shape-converting applications. Electrical pulses are used to program different emissivity states to convert geometric shapes inside a fully integrated VO2-based electro-optical window. This results in the reconfiguring of thermal images to either create new shapes, or shift from one to another.
关键词： shape-configuration,hysteresis,programming states,phase-change materials,smart materials
更新于2025-09-23 15:23:52
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - A Fast Sparse Representation Method for SAR Target Configuration Recognition
摘要： Focusing on the problem of the real-time implementation in sparse representation (SR) based recognition algorithm, a fast sparse representation (FSR) algorithm is presented in this paper to improve the efficiency of synthetic aperture radar (SAR) target configuration recognition. Taking the inertia variance characteristic of SAR target images over a small range of azimuth angles into consideration, training samples of each configuration are averaged. Instead of using all the training samples to establish the dictionary in SR, the average samples are utilized to construct the dictionary in FSR. A small dictionary accelerates the speed of the proposed algorithm.
关键词： sparse representation (SR),Synthetic aperture radar (SAR) images,target configuration recognition
更新于2025-09-23 15:22:29
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Improvement of the Beam-Wave Interaction Efficiency Based on the Coupling-Slot Configuration in an Extended Interaction Oscillator
摘要： A method aimed at improving the beam-wave interaction efficiency by changing the coupling slot configuration has been proposed in the study of extended interaction oscillators (EIOs). The dispersion characteristics, coupling coefficient and interaction impedance of the high-frequency structure based on different types of coupling slots have been investigated. Four types of coupled cavity structures with different layouts of the coupling slots have been compared to improve the beam-wave interaction efficiency, so as to analyze the beam-wave interaction and practical applications. In order to determine the improvement of the coupling slot to a coupled cavity circuit in an EIO, we designed four nine-gap EIOs based on the coupled cavity structure with different coupling slot configurations. With different operating frequencies and voltages takes into consideration, beam voltages from 27 to 33 kV have been simulated to achieve the best beam-wave interaction efficiency so that the EIOs are able to work in the 2π mode. The influence of the Rb and the ds on the output power is also taken into consideration. The Rb is the radius of the electron beam, and the ds is the width of the coupling slot. The simulation results indicate that a single-slot-type EIO has the best beam-wave interaction efficiency. Its maximum output power is 2.8 kW and the efficiency is 18% when the operating voltage is 31 kV and electric current is 0.5 A. The output powers of these four EIOs that were designed for comparison are not less than 1.7 kW. The improved coupling-slot configurations enables the extended interaction oscillator to meet the different engineering requirements better.
关键词： Output power,Coupling slot configuration,Extended interaction oscillator,Beam-wave interaction efficiency
更新于2025-09-23 15:22:29
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The effect of machining on domain configuration in [001]-oriented tetragonal Pb(Mg <sub/>1/3</sub> Nb <sub/>2/3</sub> )O <sub/>3</sub> –PbTiO <sub/>3</sub> single crystals
摘要： Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN–PT) single crystals have attracted increasing attention in electro-optic and nonlinear optical applications. In this paper, it was found that the domain configuration of PMN–PT single crystals was influenced by machining and electric process, such as cutting, grinding, polishing, and electrical field poling. The ordered herringbone/stripe domain pattern can be changed into an unexpected disordered domain state in tetragonal PMN–PT crystals which was observed in some crystal samples. Those chaotic structures can decrease transmittance and increase possibility of cracking during poling. However, the disordered domain pattern can be eliminated by a temperature cycling process. Crack-free single-domain crystals were successfully obtained by electric field poling, exhibiting complete optical extinction in an orthogonal polarized light microscope. The results suggest that the domain configuration of PMN–PT single crystals is sensitive to machining process and can be controlled by proper temperature and electric field.
关键词： domain configuration,optical properties,electric field poling,PMN–PT single crystals,temperature cycling,machining
更新于2025-09-23 15:21:21