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- 2019
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- Dual Material Gate (DMG)
- Vertical TFET
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- Band-to-band tunneling (BTBT)
- characterization
- organic light-emitting diode
- mobility
- material parameter
- doping
- Electronic Science and Technology
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- Fluxim AG
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Institute for Applied Physics, Technische Universit?t Dresden
- National Institute of Technology Silchar
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Leaf and wood classification framework for terrestrial LiDAR point clouds
摘要： 1. Leaf and wood separation is a key step to allow a new range of estimates from Terrestrial LiDAR data, such as quantifying above ground biomass, leaf and wood area, and their 3D spatial distributions. We present a new method to separate leaf and wood from single tree point clouds automatically. Our approach combines unsupervised classification of geometric features and shortest path analysis. 2. The automated separation algorithm and its intermediate steps are presented and validated. Validation consisted of using a testing framework with synthetic point clouds, simulated using ray-tracing and 3D tree models, and 10 field scanned tree point clouds. To evaluate results we calculated accuracy, kappa coefficient and F-score. 3. Validation using simulated data resulted in an overall accuracy of 0.83, ranging from 0.71 to 0.94. Per tree average accuracy from synthetic data ranged from 0.77 to 0.89. Field data results presented and overall average accuracy of 0.89. Analysis of each step showed accuracy ranging from 0.75 to 0.98. F-scores from both simulated and field data were similar, with scores from leaf usually higher than for wood. 4. Our separation method showed results similar to others in literature, albeit from a completely automated workflow. Analysis of each separation step suggests that the addition of path analysis improved the robustness of our algorithm. Accuracy can be improved with per tree parameter optimization. The library containing our separation script can be easily installed and applied to single tree point cloud. Average processing times are below 10 minutes for each tree.
关键词： field data,3D point clouds,simulated data,terrestrial LiDAR,material separation,LiDAR,testing framework
更新于2025-09-23 15:22:29
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Novel polyelectrolyte–Al2O3/SiO2 composite nanoabrasives for improved chemical mechanical polishing (CMP) of sapphire
摘要： A new type of polyelectrolyte–Al2O3/SiO2 composite nanoparticle with excellent dispersibility and superior polishing performance was successfully fabricated using a facile method. Silica acted as a bifunctional molecule by attaching to alumina via covalent bond and adsorbing polyelectrolytes by electrostatic interaction. The material removal rate of the polyelectrolyte–Al2O3/SiO2 abrasive was 30% higher than that of the pure Al2O3 abrasive. In addition, the sapphire surface was much smoother. The material removal mechanism was investigated during CMP using the microcontact and wear model. The enhanced removal rate was mainly attributed to the well-dispersed particles, which can accelerate mechanical removal process. The remarkably smooth surface was due to the decrease in penetration depth of the abrasive into the wafer. The results of this study provided a feasible strategy to satisfy the high efficiency and damage-free polishing requirements for sapphire planarization.
关键词： chemical mechanical polishing,composite abrasives,polyelectrolyte,surface roughness,sapphire,material removal rate
更新于2025-09-23 15:22:29
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[IEEE NAECON 2018 - IEEE National Aerospace and Electronics Conference - Dayton, OH, USA (2018.7.23-2018.7.26)] NAECON 2018 - IEEE National Aerospace and Electronics Conference - Impact of dielectric and magnetic losses on the negative index characteristics of a chiral material with first-order sideband dispersion
摘要： Electromagnetic propagation in chiral materials under first-order dispersion is examined for negative indices under non-conductive losses. Three loss scenarios are considered, viz., dielectric (complex permittivity) losses; magnetic (complex permeability) losses; and a combination of both types of losses to investigate the overall impact of the losses on the emergence of negative index bands.
关键词： complex permittivity and permeability,loss compensation,plane wave polarization,material dispersion,negative index bands,Negative refractive index
更新于2025-09-23 15:22:29
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[IEEE 2018 4th International Conference on Renewable Energies for Developing Countries (REDEC) - Beirut, Lebanon (2018.11.1-2018.11.2)] 2018 4th International Conference on Renewable Energies for Developing Countries (REDEC) - Phase Change Materials in a Domestic Solar Hot Water Storage Tank of the Lebanese Market
摘要： The availability of some kinds of renewable energy resources is un-continuous, for example the solar collectors can only produce heat when the sun is shining. Thermal Energy Storage (TES) is crucial to match between the intermittent solar heat supply and the heat demand. In this paper, a Phase Change Material (PCM) is integrated in the Domestic Solar Hot Water Storage Tank (DSHWST) as a Latent Heat Storage (LHT). Based on the application requirements in Lebanon, a suitable PCM is selected. While this PCM solidifies, it releases its heat and keeps the water inside the DSHWST warmer than 55 oC along 10 hours. The needed mass of PCM was calculated and two types of containers were investigated: the tubes and the spheres. As well as, the comparison between DSHWST integrated with PCM (DSHWST-PCM) and the Conventional Domestic Solar Hot Water Storage Tank (CDSHWST) is introduced, in order to examine the performance of PCM heating against that with an Electrical Resistance (ER). Features are expressed in terms of system payback and CO2 emission. Due to the issue of electrical power availability in Lebanon, the PCM integrated in The DSHWST has the following two advantages: yearly, reducing the primary electricity power by about 6.5 MWh and get rid of about 5.5 tons of CO2.
关键词： Thermal Energy Storage,Phase Change Material,Hot Water Storage Tank,Lebanon
更新于2025-09-23 15:22:29
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Evaluating impact damage to fabric-based personal armor by infrared NDT
摘要： The paper considers the thermo-mechanical mechanism of interaction between the damage agents and armor protection made of polymer fabrics. A simplified mathematical model is proposed to describe the deceleration of a damage agent within an armor fabric due to the dissipation of energy expended on irreversible stretching deformations of fabric fibers, as well as fiber slipping friction and material heating. Woven fabric layers are replaced by solid layers characterized by averaged stiffness and viscosity. A discrete numerical model of a solid material is proposed to reduce a problem with a finite number of degrees of freedom; motion equations are obtained on the basis of the Lagrange equations of the second kind, and for their integration, a stable non-conservative difference scheme is used. The software implementation is based on a functional-object paradigm which allows the modeling of conjugated processes. The parameters of governing equations are identified by using the experimental data. Some illustrative examples of interaction between damage agents and armor barriers with different arrangement of fibers are presented. The proposed model can be used to predict the quality of armor protection with the changing number and location of fibers, as well as to test the armor protection by applying the technique of infrared thermography.
关键词： Armor protection,mathematical model,irreversible deformation,infrared thermography,energy absorption,numerical scheme,composite material,fiber friction
更新于2025-09-23 15:22:29
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Electrochromic Properties of Polyaniline-Based Hybrid Organic/Inorganic Materials
摘要： Hybrid materials based on polyaniline (PAni) were obtained by in situ polymerization of aniline with chitosan and/or organically modified clay (nanomer I-24) in HCl. The samples were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and direct current (DC) electrical conductivity. Thin films of PAni, PAni-clay, PAni-chitosan and PAni-chitosan-clay were prepared by casting a solution of each sample in N-methyl-2-pyrrolidone (NMP) onto indium tin oxide (ITO)/glass electrodes and their electrochromic properties were investigated. It was observed color variation from transparent yellow in the reduced state (E = ?0.2 V vs. Ag/AgCl), green in the intermediate state (E = 0.5 V) and dark blue in the oxidized state (E = 0.8 V) for all samples. The color changes of each material in function of the applied potential were tracked using the Commission Internationale de l’Eclairage (CIE) system of colorimetry, in which the color change was much more significant for PAni-clay film.
关键词： chitosan,organophilic clay,hybrid material,conjugated polymer,polyaniline
更新于2025-09-23 15:22:29
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High-Throughput Combinatorial Synthesis of Stimuli-Responsive Materials
摘要： Stimuli-responsive materials find wide applications in different biological and medical settings. Traditionally, stimuli-responsive materials are synthesized and evaluated individually one-by-one. The drawback of this approach is the scarceness of possible combinations that can be practically tested for the purpose of saving time, consumables, and manpower. High-throughput methods are therefore important to accelerate the discovery of stimuli-responsive materials and to screen for biological interactions of interest in parallel. The objective of this article is to provide an overview of the successful employment of combinatorial high-throughput synthesis and screening of stimuli-responsive materials. In particular, these include thermoresponsive and hydroresponsive materials. Advantages of a combinatorial approach as well as of utilizing high-throughput methodologies in the development of stimuli-responsive materials are reviewed. Possible evolution trends of stimuli-responsive materials, advanced by high-throughput methodologies, are discussed.
关键词： combinatorial libraries,material microarrays,smart materials,stimuli-responsive,high-throughput synthesis
更新于2025-09-23 15:22:29
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Microwave transmission performance of fused silica ceramics in microwave high-temperature heating
摘要： Compared with traditional heating methods, microwave heating is widely used in many industrial heating fields because of its advantages, such as material-selective heating, volumetric heating and high-efficiency heating. However, previous studies have shown that the heating mode depends on the transmission performance of refractory insulation materials. In this study, a commonly used refractory material (fused silica ceramics) for microwave heating was studied, according to the law of electromagnetic wave propagation in a single-layer plate, the power transmission coefficient (PTC) of the material at different thickness, temperature and frequency (915 MHz and 2360 MHz) was calculated and analysed, in order to design the refractory structure which has good microwave transmission performance in the whole microwave heating process. The results show that the transmission performance of fused silica ceramics fluctuates regularly with increasing thickness, and there are several microwave transmission peaks in the PTC patterns, the thicknesses corresponding to the transmission peaks at frequency 2360 MHz are in order 0.033 m, 0.065 m and 0.098 m; as the temperature increases, the position of the transmission peaks will shift to a smaller thickness, the transmission performance of fused silica ceramics decreases slightly with increasing temperature. Comparing the transmission performance of mullite, alumina (Al2O3) and fused silica ceramics, it was found that the fused silica ceramics have excellent transmission properties; especially it is at high temperature. The results of this study can provide guidance for the selection of refractory structure materials and sizes as well as the optimization of heating process parameters in high-temperature microwave heating.
关键词： A. Microwave heating,D. Transmission performance,B. Fused silica ceramic,C. High temperature wave transmitting material
更新于2025-09-23 15:22:29
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Constituent substitution in hot wall deposition of Bi2S3 films by reaction with substrates
摘要： Replacement of a constituent in the overgrown layers with the materials provided by the substrates is investigated when Bi2S3 films are deposited on III-V compound semiconductors and transition metals using a hot wall epitaxy method. The substitution caused by the S atoms is stronger than that by the Se and Te atoms in deposition of Bi2Se3 and Bi2Te3 films. Mere exposure to Bi2S3 vapor of In-containing compounds (InP and InAs) and Ga-containing compounds (GaAs and GaSb) at epitaxial growth temperatures results in a capping of their surfaces by In2S3 and GaS, respectively. A temperature window is revealed to exist for the GaAs case where growth of Bi2S3 microcrystals occurs within the temperature range for the sulfide formation. The sulfurization by the material substitution is thus demonstrated to be not always identical with that using elemental sulphur. We examine furthermore the sulfides synthesized on the surfaces of Cu, Ag, Ni, Mo, and W. The sulfides produced on Cu and Ag undergo material alterations when they are irradiated by a laser light.
关键词： X-ray crystallography,Hot wall epitaxy,Material substitution,Raman spectroscopy,Bi2S3,Sulfides
更新于2025-09-23 15:22:29
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Optimization of formaldehyde detection performance based on Ni2+ sensitized monodisperse amorphous zinc tin oxide microcubes
摘要： The pure and Ni2+ sensitized monodisperse amorphous zinc tin oxide (a-ZTO) microcubes were synthesized via an in-situ precipitation method and subsequent wet impregnation. XPS results revealed that Ni2+ sensitization increased the relative content of chemisorbed oxygen and oxygen vacancies on the surface of a-ZTO microcubes. Compared to pure a-ZTO microcubes, 0.75 at% Ni2+ sensitized a-ZTO microcubes can significantly improve the gas sensing performance to formaldehyde at 200 °C, which may be attributed to its uniform morphology and modification of Ni2+ on the surface of a-ZTO microcubes. Further, the gas sensing mechanism is briefly discussed.
关键词： Surface sensitization,Zinc tin oxide,Monodisperse,Amorphous material,Sensors
更新于2025-09-23 15:22:29