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- 实验方案
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Growth of Large-Area, Uniform, Few-Layer Tungsten Disulphide by Thermal Decomposition of Ammonium Tetrathiotungstate
摘要： Two-dimensional transition metal dichalcogenides (2D-TMDCs) such as molybdenum disulphide (2D-MoS2) and tungsten disulphide (2D-WS2) are now established as a class of nanomaterials that can be used in numerous applications due to their tuneable physical and chemical properties [1]. However, in terms of electrical characteristics and photoluminescence efficiency, WS2 typically exhibits superior performance compared with the molybdenum analogue [2,3]. Nevertheless, synthesis of continuous, uniform and thickness controllable 2D-WS2 films for (opto)electronic device fabrication is more challenging compared with better established 2D-MoS2 growth protocols. Therefore, the search for alternative precursors and synthesis approaches of 2D-WS2 that can provide mass production with excellent quality at low cost is highly desirable [1]. In this work, we tackle this issue by refining the solvents recipe with n-methylpyrrolidone, n-butylamine and 2-aminoethanol, which significantly improves the continuity, uniformity and thickness controllability for the spin-coated precursor films. This enables the large-area growth of few-layer WS2 films using thermal decomposition via two-step high temperature annealing without sulphurisation. The few-layer WS2 films were characterised by optical and atomic force microscopy to confirm the continuity and two-dimensional nature of the deposited WS2 films. Raman, photoluminescence and x-ray photoelectron spectroscopy indicate growth of highly crystalline films with an optimum composition of WS2. The electrical response of the WS2 films grown by this method was investigated by interrogating a back-gate thin film transistor utilising a WS2 channel as shown in Figure 1.
关键词： ammonium tetrathiotungstate,Tungsten disulphide,few-layer,large-area growth,thermal decomposition
更新于2025-09-16 10:30:52
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Accurate, Fast and Robust Beam Characterization for Fiber Beams Based on Deep Learning
摘要： Fiber beam characterization based on deep learning, including mode decomposition and M2 evaluation, has been simulation and experiment. Deep learning enables not only high accuracy and speed but also high anti-noise ability.
关键词： Beam Quality,Mode Decomposition,Beam Characterization,Deep Learning
更新于2025-09-16 10:30:52
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Synthesis and characterization of Mono-disperse Carbon Quantum Dots from Fennel Seeds: Photoluminescence analysis using Machine Learning
摘要： Herein, we present the synthesis of mono-dispersed c-QDs via single-step thermal decomposition process using the fennel seeds (Foeniculum vulgare). As synthesized c-QDs have excellent colloidal, photo-stability, environmental stability (pH) and do not require any additional surface passivation step to improve the fluorescence. The C-QDs show excellent PL activity and excitation-independent emission. Synthesis of excitation-independent c-QDs, to the best of our knowledge, using natural carbon source via pyrolysis process has never been achieved before. The effect of reaction time and temperature on pyrolysis provides insight into the synthesis of c-QDs. We used Machine-learning techniques (ML) such as pcA, McR-ALS, and nMf-ARD-So in order to provide a plausible explanation for the origin of the pL mechanism of as-synthesized c-QDs. ML techniques are capable of handling and analyzing the large pL data-set, and institutively recommend the best excitation wavelength for pL analysis. Mono-disperse c-QDs are highly desirable and have a range of potential applications in bio-sensing, cellular imaging, LeD, solar cell, supercapacitor, printing, and sensors.
关键词： Machine learning,Fennel seeds,Thermal decomposition,Photoluminescence,Carbon quantum dots
更新于2025-09-16 10:30:52
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[IEEE 2019 IEEE International Electron Devices Meeting (IEDM) - San Francisco, CA, USA (2019.12.7-2019.12.11)] 2019 IEEE International Electron Devices Meeting (IEDM) - First Demonstration of Waveguide-Integrated Black Phosphorus Electro-Optic Modulator for Mid-Infrared Beyond 4 ??m
摘要： Matrix inversion is a fundamental operation for solving linear equations for many computational applications, especially for various emerging big data applications. However, it is a challenging task to invert large-scale matrices of extremely high order (several thousands or millions), which are common in most Web-scale systems, such as social networks and recommendation systems. In this paper, we present a lower upper decomposition-based block-recursive algorithm for large-scale matrix inversion. We present its well-designed implementation with optimized data structure, reduction of space complexity, and effective matrix multiplication on the Spark parallel computing platform. The experimental evaluation results show that the proposed algorithm is efficient to invert large-scale matrices on a cluster composed of commodity servers and is scalable for inverting even larger matrices. The proposed algorithm and implementation will become a solid foundation for building a high-performance linear algebra library on Spark for big data processing and applications.
关键词： linear algebra,parallel algorithm,distributed computing,Matrix inversion,LU decomposition,Spark
更新于2025-09-16 10:30:52
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400 Gb/s Silicon Photonic Transmitter and Routing WDM technologies for glueless 8-socket Chip-to-Chip interconnects
摘要： A novel frequency-based classification framework and new wavelet algorithm (Wave-CLASS) is proposed using an overcomplete decomposition procedure. This approach omits the downsampling procedure and produces four-texture information with the same dimension of the original image or window at infinite scale. Three image subsets of QuickBird data (i.e., park, commercial, and rural) over a central region in the city of Phoenix were used to examine the effectiveness of the new wavelet overcomplete algorithm in comparison with a widely used classical approach (i.e., maximum likelihood). While the maximum-likelihood classifier produced < 78.29% overall accuracies for all three image subsets, the Wave-CLASS algorithm achieved high overall accuracies—95.05% for the commercial subset (Kappa = 0.94), 93.71% for the park subset (Kappa = 0.93), and 89.33% for the rural subset (Kappa = 0.86). Results from this study demonstrate that the proposed method is effective in identifying detailed urban land cover types in high spatial resolution data.
关键词： overcomplete decomposition,high spatial resolution,infinite scale,urban land cover,Classification,wavelet transforms
更新于2025-09-16 10:30:52
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Nonlocal Coupled Tensor CP Decomposition for Hyperspectral and Multispectral Image Fusion
摘要： Hyperspectral (HS) super-resolution, which aims at enhancing the spatial resolution of hyperspectral images (HSIs), has recently attracted considerable attention. A common way of HS super-resolution is to fuse the HSI with a higher spatial-resolution multispectral image (MSI). Various approaches have been proposed to solve this problem by establishing the degradation model of low spatial-resolution HSIs and MSIs based on matrix factorization methods, e.g., unmixing and sparse representation. However, this category of approaches cannot well construct the relationship between the high-spatial-resolution (HR) HSI and MSI. In fact, since the HSI and the MSI capture the same scene, these two image sources must have common factors. In this paper, a nonlocal tensor decomposition model for hyperspectral and multispectral image fusion (HSI-MSI fusion) is proposed. First, the nonlocal similar patch tensors of the HSI are constructed according to the MSI for the purpose of calculating the smooth order of all the patches for clustering. Then, the relationship between the HR HSI and the MSI is explored through coupled tensor canonical polyadic (CP) decomposition. The fundamental idea of the proposed model is that the factor matrices in the CP decomposition of the HR HSI’s nonlocal tensor can be shared with the matrices factorized by the MSI’s nonlocal tensor. Alternating direction method of multipliers is used to solve the proposed model. Through this method, the spatial structure of the MSI can be successfully transferred to the HSI. Experimental results on three synthetic data sets and one real data set suggest that the proposed method substantially outperforms the existing state-of-the-art HSI-MSI fusion methods.
关键词： nonlocal tensor,multispectral images (MSIs),Coupled canonical polyadic (CP) decomposition,data fusion,hyperspectral images (HSIs)
更新于2025-09-16 10:30:52
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Formation Thermodynamics, Stability, and Decomposition Pathways of CsPbX <sub/>3</sub> (X = Cl, Br, I) Photovoltaic Materials
摘要： Standard enthalpies of formation of CsPbX3 (X = Cl, Br, I) perovskites from halides and from elements at 298 K were measured using solution calorimetry. Intrinsic and extrinsic stabilities of CsPbX3 halides were analyzed and compared with those of CH3NH3PbX3. The main difference between the stabilities of CsPbX3 and CH3NH3PbX3 halides was found to stem from the different chemical nature of cesium and methylammonium cations. Indeed, the enthalpies of formation of CsPbX3 from binary constituent halides, ?fH○hal, are only slightly more negative than those of CH3NH3PbX3. Small values of ?fH○hal imply that the entropic contribution to the Gibbs free energy of formation of CsPbX3 and CH3NH3PbX3 is significant and, hence, of utmost importance for understanding the intrinsic stability of these compounds and their analogs. Regarding the extrinsic stability, the presence of gaseous O2, H2O, and CO2 was shown to be crucial for the stability of the iodide, CsPbI3, for which several decomposition reactions, exergonic at 298 K, were identified. At the same time, chloride, CsPbCl3, and bromide, CsPbBr3, are much less sensitive to these chemical agents. However, liquid water should degrade all the CsPbX3 halides.
关键词： Plasmonics,Stability,Decomposition Pathways,Hybrid Materials,Thermodynamics,Magnetic,Photovoltaic Materials,CsPbX3,Optical
更新于2025-09-16 10:30:52
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Eliminating Phase Drift for Distributed Optical Fiber Acoustic Sensing System with Empirical Mode Decomposition
摘要： Phase-drift elimination is crucial to vibration recovery in the coherent detection phase-sensitive optical time domain re?ectometry system. The phase drift drives the whole phase signal ?uctuation as a baseline, and its negative e?ect is obvious when the detection time is long. In this paper, empirical mode decomposition (EMD) is presented to extract and eliminate the phase drift adaptively. It decomposes the signal by utilizing the characteristic time scale of the data, and the baseline is eventually obtained. It is validated by theory and experiment that the phase drift deteriorates seriously when the length of the vibration region increases. In an experiment, the phase drift was eliminated under the conditions of di?erent vibration frequencies of 1 Hz, 5 Hz, and 10 Hz. The phase drift was also eliminated with di?erent vibration intensities. Furthermore, the linear relationship between phase and vibration intensity is demonstrated with a correlation coe?cient of 99.99%. The vibrations at 0.5 Hz and 0.3 Hz were detected with signal-to-noise ratios (SNRs) of 55.58 dB and 64.44 dB. With this method, when the vibration frequency is at the level of Hz or sub-Hz, the phase drift can be eliminated. This contributes to the detection and recovery of low-frequency perturbation events in practical applications.
关键词： phase drift elimination,phase recovery,phase-sensitive optical time domain re?ectometry,distributed acoustic sensing system,empirical mode decomposition
更新于2025-09-12 10:27:22
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[IEEE 2019 3rd International Symposium on Multidisciplinary Studies and Innovative Technologies (ISMSIT) - Ankara, Turkey (2019.10.11-2019.10.13)] 2019 3rd International Symposium on Multidisciplinary Studies and Innovative Technologies (ISMSIT) - Manufacturing Graphene via Laser Heating
摘要： This study focuses on the investigation of an alternative method for graphene production. There are various ways of manufacturing graphene sheets. Each method has it is own advantages and disadvantages. However, the common problem is about the cost and time associated with these particular routes. In this study, we have developed an alternative mechanism that utilizes laser beam as heating source to help thermal decomposition of silicon carbide in order to obtain graphene sheets. The manufactured samples were compared with graphene sheets that were prepared with traditional thermal decomposition method using a high temperature furnace. The results showed that the alternative way of manufacturing has promise for graphene formation since Raman spectrum showed graphene peaks in corresponding locations with satisfactory shapes. This could lead to potentially single layer graphene on a large scale after optimizing the manufacturing setup and, consequently, could either reduce the fabrication costs or reduce the time required for epitaxial growth process. Few rearrangements such as laser power, flow rate of the gas or pressurizing the chamber could make the process an applicable approach.
关键词： epitaxial growth,laser-heating,thermal decomposition,graphene
更新于2025-09-12 10:27:22
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Synthesis and characterization of size controlled alloy nanoparticles
摘要： Bimetallic and multimetallic alloy nanoparticles are emerging as a class of critical nanomaterials in electronic, optical and magnetic fields due to their unique physic-chemical properties. In particular, precise control of the nanoparticle size can endow them with broad versatility and high selectivity. This chapter reviews some tremendous achievements in the development of size controlled bimetallic and multimetallic alloy nanoparticles, with special emphasis on general preparation methods, characterization methodologies and instrumentation techniques. Some key factors and future perspectives on the development of size-controlled bimetallic and multimetallic alloy nanoparticles are also discussed.
关键词： Thermal decomposition,Bimetallic and multimetallic alloy nanoparticles,Chemical reduction,Electrochemical deposition,Controlled size
更新于2025-09-12 10:27:22