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Prediction of two-dimensional topography of laser cladding based on neural network
摘要： The two-dimensional morphology of the cladding layer has an important influence on the quality of the cladding layer and the crack tendency. Using the powerful nonlinear processing ability of the single hidden layer feedforward neural network, a prediction model between the cladding technological parameters and the two-dimensional morphology of the cladding layer is established. Taking the cladding parameters as the input and the two-dimensional morphology of the cladding as the output, the experimental data is used to train the network to achieve a high-level mapping of the input and output. On this basis, the algorithm of extreme learning machine is used to optimize the single hidden layer feedforward neural network to overcome the problems of slow convergence speed, more network training parameters and easy local convergence in back-propagation algorithm. The results show that the relationship between the cladding process parameters and the two-dimensional morphology of the cladding layer can be roughly reflected by the back-propagation algorithm. However, the prediction results are not stable and the error rate is between 10% and 40%. The neural network optimized by the extreme learning machine is utilized to get a better prediction result. The error rate is 10–20%.
关键词： extreme learning machine.,BP neural network,Layer cladding,morphology prediction
更新于2025-11-28 14:24:20
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Microstructural characterization of nanostructured Al2O3-ZrO2 eutectic layer by laser rapid solidification method
摘要： In the present work, nanostructured surface layers of Al2O3-ZrO2 eutectic with a thickness of approximate 1000 μm and free of cracks and pores were produced on the surface of conventionally-sintered Al2O3-ZrO2 ceramic via the laser irradiation rapid solidification process. The molten pool geometry and microstructure were characterized by scanning electron microscopy and Raman spectroscopy. The geometrical evolution of molten pool in response to laser power and laser scanning velocity was established, where the top view of molten pool exhibits a circular shape at low velocities and gradually evolves into an oval-shaped surface at high velocities. Singular Al2O3-ZrO2 eutectic colonies with a size of 100-200 μm, which is formed around a spontaneously nucleated dendritic ZrO2 core, are found on the surface of laser-remelted layer. The eutectic colony has an interphase spacing of 190-280 nm. The variation of eutectic spacing with growth rate is essentially linear on the logarithmic scale as λ=KV-0.4 by binary regression analysis. Predicted by the Jackson-Hunt theory on eutectic solidification (JH theory), the eutectic spacing is consistent with the inverse-square-root dependence on growth rate with a proportionality constant of 3.32. The eutectic colonies consist of α-Al2O3, t-ZrO2 and m-ZrO2 phases, where α-Al2O3 and t-ZrO2 are the dominant phases and the m-ZrO2 phase increases with the decrease of laser scanning velocity.
关键词： Al2O3-ZrO2,Nanoeutectic layer,Laser remelting,Surface nanostructuring
更新于2025-11-28 14:24:20
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Ultrasensitive tantalum oxide nano-coated long-period gratings for detection of various biological targets
摘要： In this work we discussed a label-free biosensing application of long-period gratings (LPGs) optimized in refractive index (RI) sensitivity by deposition of thin tantalum oxide (TaOx) overlays. Comparing to other thin film and materials already applied for maximizing the RI sensitivity, TaOx offers good chemical and mechanical stability during its surface functionalization and other biosensing experiments. It was shown theoretically and experimentally that when RI of the overlay is as high as 2 in IR spectral range, for obtaining LPGs ultrasensitive to RI, the overlay’s thickness must be determined with subnanometer precision. In this experiment the TaOx overlays were deposited using Atomic Layer Deposition method that allowed for achieving overlays with exceptionally well-defined thickness and optical properties. The TaOx nano-coated LPGs show RI sensitivity determined for a single resonance exceeding 11,500 nm/RIU in RI range nD=1.335-1.345 RIU, as expected for label-free biosensing applications. Capability for detection of various in size biological targets, i.e., proteins (avidin) and bacteria (Escherichia coli), with TaOx-coated LPGs was verified using biotin and bacteriophage adhesin as recognition elements, respectively. It has been shown that functionalization process, as well as type of recognition elements and target analyte must be taken into consideration when the LPG sensitivity is optimized. In this work optimized approach made possible detection of small in size biological targets such as proteins with sensitivity reaching 10.21 nm/log(ng/ml).
关键词： protein detection,label-free biosensing,optical fiber sensor,tantalum oxide,bacteria detection,long-period grating,atomic layer deposition
更新于2025-11-28 14:23:57
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2D electric-double-layer phototransistor for photoelectronic and spatiotemporal hybrid neuromorphic integration
摘要： The hardware implementation of neuromorphic computing has attracted growing interest as a promising candidate for confronting the bottleneck of traditional von Neumann computers. However, most previous reports are focused on emulating the synaptic behaviors by a mono-mode using an electric-driving or photo-driving approach, resulting in a big challenge to synchronously handle the natural photoelectric information. Herein, we report a multifunctional photoelectronic hybrid-integrated synaptic device based on the electric-double-layer (EDL) MoS2 phototransistor. Interestingly, the electric MoS2 synapse exhibits a potentiation filtering effect, while the photonic counterpart can implement both potentiation and depression filtering effects. Most importantly, for the first time, photoelectronic and spatio-temporal four-dimensional (4D) hybrid integration was successfully demonstrated by the synergic interplay between photonic and electric stimuli within a single MoS2 synapse. An energy band model is proposed to further understand such a photoelectronic and spatio-temporal 4D hybrid coupling mechanism. These results might provide an alternative solution for the size-scaling and intellectualization campaign of the post-Moore era, and for more sophisticated photoelectronic hybrid computing in the emerging neuromorphic nanoelectronics.
关键词： neuromorphic computing,electric-double-layer,synaptic device,MoS2 phototransistor,photoelectronic hybrid integration
更新于2025-11-25 10:30:42
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Triple-Junction Optoelectronic Sensor with Nanophotonic Layer Integration for Single Molecule Level Decoding
摘要： Interest in developing a rapid and robust DNA sequencing platform has surged over the past decade. Various next-/third-generation sequencing mechanisms have been employed to replace the traditional Sanger sequencing method. In sequencing by synthesis (SBS), a signal is monitored by a scanning charge-coupled device (CCD) to identify thousands to millions of incorporated dNTPs with distinctive fluorophores on a chip. Because one reaction site usually occupies dozens of pixels on a CCD detector, a bottleneck related to the bandwidth of CCD imaging limits the throughputs of the sequencing performance and causes tradeoffs among speed, accuracy, read length, and the numbers of reaction sites in parallel. Thus, current research aims to align one reaction site to a few pixels by directly stacking nanophotonic layers (NPLs) onto a CMOS detector to minimize the size of the sequencing platforms and accelerate the processing procedures. This article reports a custom integrated optoelectronic device based on a triple-junction photodiode (TPD) CMOS sensor in conjunction with NPL integration for real-time illumination and detection of fluorescent molecules.
关键词： planar waveguide,nanophotonic layer,CMOS,triple-junction photodiode (TPD),filter,grating
更新于2025-11-25 10:30:42
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Dual-Functional Long-Term Plasticity Emulated in IGZO-Based Photoelectric Neuromorphic Transistors
摘要： Indium–gallium–zinc-oxide (IGZO) photoelectric neuromorphic transistors with low-temperature atomic layer deposited Al2O3 gate dielectrics are fabricated. Dual-functional long-term plasticity, including long-term depression (LTD) and long-term potentiation (LTP), is emulated. The emulation of LTD is achieved by applying high-electrical pulse trains on the gate electrode. The LTP emulation is realized by applying light pulse trains on the IGZO channel layer. The operation mechanisms of the LTD and the LTP are discussed based on the electron/hole trapping in the Al2O3 gate dielectrics and the persistent photoconductivity of the IGZO channel layer.
关键词： Neuromorphic transistors,long-term plasticity,atomic layer deposition
更新于2025-11-25 10:30:42
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Investigation on the crack fracture mode and edge quality in laser dicing of glass-anisotropic silicon double-layer wafer
摘要： This work puts forward numerical and experimental investigations on laser dicing of glass-anisotropic single-crystal silicon double-layer wafer using laser induced thermal-crack propagation (LITP). A semiconductor continuous wave laser working at the defocusing mode serves as volumetric heat source for glass layer while as surface heat source for silicon layer. Based on the classical fracture theory, a static seam-type crack is introduced under the circumstance of ABAQUS to simulate the crack fracture modes in glass layer as well as silicon layer with crystal planes of (100), (110) and (111) during laser dicing in different dicing directions. In the experiments, processing parameters are kept the same as the simulations and typical dicing directions obtained from simulations are also used. The surface morphologies of crack edges are measured by the optical microscope and surface profiler. Through the comparison of numerical and experimental results it is discovered that for the specific substrate, the evolution of crack edge qualities in different dicing directions and different layers can be interpreted based on the corresponding stress distribution and stress intensity factor (SIF) ratio explicitly. And most important of all, the anisotropy of silicon layer has significant influence on the fracture mode and edge quality of crack in both layers.
关键词： Crack fracture mode,Laser induced thermal-crack propagation,Glass-anisotropic single-crystal silicon double-layer wafer,Crack edge quality,Static seam-type crack
更新于2025-11-21 11:24:58
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AIP Conference Proceedings [Author(s) PROCEEDINGS OF THE 3RD INTERNATIONAL CONFERENCE ON AUTOMOTIVE INNOVATION GREEN ENERGY VEHICLE: AIGEV 2018 - Kuantan, Malaysia (25–26 July 2018)] - Chemical bath deposition of In2S3 thin films as promising material and buffer layer for solar cells
摘要： The copper(I) and indium thin films are obtained by chemical bath deposition (CBD). Their elemental composition and microstructure were particularly studied by means of the x-ray photoelectron spectroscopy (XPS). The change in the surface microstructure of thin films depending on the temperature and the composition of reaction bath were determined by means of scanning electron microscopy (SEM).
关键词： chemical bath deposition,solar cells,thin films,buffer layer,In2S3
更新于2025-11-21 11:20:48
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Effect of incorporation of sulphur on the structural, morphological and optical studies of CdSe thin films deposited by solution processed spin coating technique
摘要： Ternary compound semiconductor CdSexS1-x (x = 1, 0.8, 0.6, 0.4, 0.2 and 0) thin films were prepared on glass substrates by using simple solution processed spin coating technique. Cadmium acetate, sodium selenosulfate and thiourea were used as source materials for Cd2+, Se2? and S2? ions, while triethanolamine was used as a capping agent. The 25% concentred NH4OH solution was used as a complex reagent and also used to adjust the pH of the final solution ~ 11. The deposition conditions (rotation speed 2000 rpm for 30 s and substrate dried in the air at 120 °C for 2 min) were remain same for all the samples. The as-deposited thin films on glass substrate were annealed at 350 °C for 30 min. The X-ray diffraction pattern shows that all the samples were polycrystalline in the nature with hexagonal structure. The most of prepared thin films were highly textured along (002) plane and peak position for plane (002) is shifted with change in composition ‘x’. The average crystallite size in CdSexS1-x thin films were found between 62.6 nm to 93.4 nm. Scanning electron microscopy images showed uniform deposition morphology with spherical shaped grains distributed over entire glass substrate. Samples CdSe0.8S0.2 and CdSe0.6S0.4 thin films indicated interesting morphological features with the combination of spherical shaped nanoparticles and interconnected nanofibers which form hierarchical flowerlike micro-structure. Energy dispersive X-Ray studies confirmed that thin films were having approximately same stoichiometry of atomic ratio of elements Cd, Se and S as present in volumetric ratio of the reactants in chemical solution. Fourier transform infrared studies confirmed the formation of the Cd(Se,S) bonding in materials. The optical band gap of CdSexS1-x thin films were found as direct band gap in the range of 1.82 eV to 2.32 eV. As the incorporation of sulphur element increases, the band gap of CdSexS1-x thin film also increases. The CdSexS1-x thin films can be used as absorption layer in solar photovoltaic cell which is due to wide and fine tenability of the energy band gap.
关键词： Nanofibers,Spin coating,Absorption layer,cadmium sulfide,Cadmium selenide,Hierarchical flowerlike microstructure,Ternary compound semiconductor
更新于2025-11-21 11:18:25
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Enhanced working efficiency of Si solar cell by water induced nano-porous thermal cooling layer
摘要： Nano-porous thermal cooling layer (TCL) of thickness 14 mm beneath a Si solar cell reduces its working temperature from 82 °C to 68 °C This reduced working temperature increase its absolute working ef?ciency by 0.75%. X-Ray diffraction analysis of the material used in TCL shows its amorphous nature. The SEM images con?rm interconnected carbon particles are forming micro-channels within the TCL. Further FESEM analysis has been done to examine the in-depth structure of the carbon particles and shows the nano-porous topography within the particle. The porosity of used TCL is examined by BET measurement which con?rms the highly porous nature of the TCL having surface area of the order of 798.35 m2 g?1 with average pore size of 2.3 nm. The induced water concentration (0.049 to 0.49 ml cm?3) dependent enhanced cooling ef?ciency of nano-porous TCL has been studied in detail. The use of water saturated (0.49 ml cm?3) TCL (14 mm thick) further decreases the working temperature of the device from 68 °C to 58 °C and the device works below this temperature for around three hours. Further, in order to enhance the effective time duration, the TCL thickness (4 mm to 26 mm) dependent cooling ef?ciency of water saturated TCL has been analyzed in detail. Use of optimized water saturated TCL beneath the solar cell improve its working ef?ciency from 11.4% (at 82 °C) to 12.69% (at 58 °C) which shows an absolute and relative enhancement of 1.29% and 11.32%, respectively in cell ef?ciency. Finally, thermal analyses of TCL and water cooling mechanism in it have been discussed in detail.
关键词： ef?ciency enhancement,Si solar cell,thermal cooling layer,cooling plateau,cooling agent,nano-porous
更新于2025-11-21 11:18:25