- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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BaV2O6·H2O: A nonlinear optical crystal with a large bandgap
摘要： The first Ba-containing hydrated vanadate as nonlinear optical (NLO) material, BaV2O6·H2O, was synthesized by facile hydrothermal method. The single-crystal X-ray diffraction result shows that this compound crystallizes in the acentric orthorhombic space group of P212121 with cell parameters a = 7.3993(6) ?, b = 8.9934(7) ?, and c = 9.7206(8) ?. UV–vis-IR diffuse reflectance spectrum shows that the compound has a large bandgap of 4.60 eV and moderate transparency range. The title compound shows second-harmonic generation (SHG) efficiency about 0.5 times of KH2PO4 (KDP). The structure-property relationship of BaV2O6·H2O was clarified by the first-principles studies.
关键词： Vanadate,Nonlinear optical material,Large bandgap,Hydrothermal method
更新于2025-09-23 15:22:29
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Perforating Freestanding Molybdenum Disulfide Monolayers with Highly Charged Ions
摘要： Porous single layer molybdenum disulfide (MoS2) is a promising material for applications such as DNA sequencing and water desalination. In this work, we introduce irradiation with highly charged ions (HCIs) as a new technique to fabricate well-defined pores in MoS2. Surprisingly, we find a linear increase of the pore creation efficiency over a broad range of potential energies. Comparison to atomistic simulations reveals the critical role of energy deposition from the ion to the material through electronic excitation in the defect creation process, and suggests an enrichment in molybdenum in the vicinity of the pore edges at least for ions with low potential energies. Analysis of the irradiated samples with atomic resolution scanning transmission electron microscopy reveals a clear dependence of the pore size on the potential energy of the projectiles, establishing irradiation with highly charged ions as an effective method to create pores with narrow size distributions and radii between ca. 0.3 and 3 nm.
关键词： 2D material,perforation,ion irradiation,MD simulation,molybdenum disulfide,highly charged ions,STEM
更新于2025-09-23 15:22:29
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Single-Layer Ag <sub/>2</sub> S: A Two-Dimensional Bidirectional Auxetic Semiconductor
摘要： Two-dimensional auxetic materials have attracted considerable attention due to their potential applications in medicine, tougher composites, defense and so on. However, they are scare especially at low dimension, as auxetic materials are mainly realized in engineered materials and structures. Here using first-principles calculations, we identify a compelling two-dimensional auxetic material, single-layer Ag2S, which possesses large negative Poisson’s ratios in both in-plane and out-of-plane directions, but anisotropic ultra-low Young’s modulus. Such a coexistence of simultaneous negative Poisson’s ratios in two directions is extremely rare, which is mainly originated from its particular zigzag-shaped buckling structure. In addition, contrary to the previously known metal-shrouded single-layer M2X (M = metal, X = nonmetal), single-layer Ag2S is the first nonmetal-shrouded M2X. Electronic calculations show that it is an indirect-gap semiconductor with gap value of 2.83 eV, and it can be turned to be direct with strain. These intriguing properties make single-layer Ag2S a promising auxetic material in electronics and mechanics.
关键词： ultra-low Young’s modulus,two-dimensional,buckling structure,auxetic material
更新于2025-09-23 15:22:29
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Self-Floating Carbonized Tissue Membrane Derived from Commercial Facial Tissue for Highly Efficient Solar Steam Generation
摘要： Solar steam generation holds a great promise for practically utilizing solar energy in sea water desalination and sewage purification on a large scale. It has been proven that local heating of the superficial water can maximize the energy efficiency for steam generation. So the photothermal materials are required to float on water while working. However, the fabrication of a photothermal material with self-floating ability, low cost and easy-preparation for solar steam generation is highly challenged. Herein, self-floating carbonized tissue membrane for high efficiency solar steam generation is prepared via the carbonization of the commercial facial tissue. The low-cost and scalable carbonized tissue membrane can float on water without any assistance, and can effectively generate water steam at the rate of 4.45 kg m-2 h-1 with photothermal conversion efficiency of as high as 95 % under 3-sun illumination. The self-floating ability, high solar steam generation performance and low cost make the carbonized tissue membrane to be potential alternative for practical application in the future.
关键词： Self-floating,Membrane,One-step synthesis,Carbon material,Solar steam generation
更新于2025-09-23 15:22:29
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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 - An Approach for Road Material Identification By Dual-Stage Convolutional Networks
摘要： The automatic extraction of road network information from satellite images is a meaningful and challenging task. Particularly, the analysis of road surface materials is very important during transport construction and maintenance. This paper proposes a method to extract road area and identify its corresponding materials. The approach is based on two different convolutional neural network structures. Firstly, we use encoder-decoder symmetric network structure to extract the candidate road area. Then the former outputs is processed by atrous convolutional network with very deep layers, in order to classify the covered substances through their representative spectral features. We also utilize the physical characteristics of road network to design morphology approach to enhance the completeness and formation of the road network. Experiential results on various satellite images show that the method can yields better accuracy and adaptability than other convolutional network based methods.
关键词： road region extraction,convolutional networks,image segmentation,Remote sensing,road material classification
更新于2025-09-23 15:22:29
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Electromagnetic wave cloaking and scattering around an antiresonance-resonance symmetrical pair in the frequency domain
摘要： Cloaking and scattering cancellation of electromagnetic waves have attracted much attention since they allow control of rf and light waves and are of scientific interest. The analytical results demonstrated in this paper reveal that plasmonic cloaking, which is one of the schemes for scattering cancellation, occurs in the vicinity of Tonks-Dattner resonances in the frequency domain, where resonances enhance wave scattering. This antiresonance-resonance pair for cloaking and scattering is cross-correlated by the symmetrical locations above and below the electron plasma frequency, respectively. However, the cloaking effect is almost independent of electron collisions with neutral particles, whereas scattering at resonance is fairly sensitive to them, leading to unclear resonance. An experimental verification of this analytical prediction is performed for the cloaking effect on working points passing through the cloaking condition and approaching resonance, which is dynamically controlled by changing the electron density. Numerical calculations based on a model configuration similar to the experimental setup confirm scattering cancellation and an increase in scattering as the points get close to the resonance condition. These results are direct evidence of scattering cancellation with a uniform epsilon-near-zero material and demonstrate the effectiveness of plasma as a cloaking material.
关键词： plasma,electromagnetic cloaking,scattering cancellation,Tonks-Dattner resonances,epsilon-near-zero material
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE 8th International Conference on Consumer Electronics - Berlin - Berlin (2018.9.2-2018.9.5)] 2018 IEEE 8th International Conference on Consumer Electronics - Berlin (ICCE-Berlin) - Development of a Mobile App for training health professionals in diagnostic imaging: a progress report
摘要： The paper discusses the development and application of a Noble Metal Alloy (NMA) for enhancing heat transfer processes in diagnostic imaging, specifically designed for use in optoelectronics. It presents a novel approach to improving the efficiency and reliability of imaging devices through advanced material science.
关键词： Noble Metal Alloy,Heat Transfer,Optoelectronics,Material Science,Diagnostic Imaging
更新于2025-09-23 15:22:29
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Preparation of a Photoactive 3D Polymer Pillared with Metalloporphyrin
摘要： Among the very few efforts for the preparation of stable pillared graphene nanostructures, there is no report of tin porphyrin intercalated between TiO2-graphene (TG) nanosheets. In this study, a nanostructure material of pillared graphene made of tin porphyrin functionalized graphene-TiO2 composite (TG) was successfully synthesized. The prepared compound showed high activity in the photodegradation reaction under irradiation of visible light. Photocatalytic results showed that the composite of graphene-TiO2 containing 3% graphene had the highest photoactivity. The photoactivity of TG (3%) was about 1.5 times higher than that of the pure TiO2. Besides, tin porphyrin-pillared TG composite (TGSP) material exhibited an excellent visible light photocatalytic performance in degradation of methyl orange dye. This compound could destruct 100% of methyl orange dye in 180 min. Such pillared carbon nanostructure exhibited unique photoactivity due to the synergistic effect between the graphene sheets and the SnTCPP pillars. It is found that the highly efficient light-harvesting structure of the SnTCPP pillared TG composite can be attributed to densely embedded porphyrin chromophores with high visible absorptivity within the framework. The investigation of photocatalytic mechanism determined that hydroxyl radical is a main species in photodegradation process of methyl orange over TGSP compound.
关键词： Semiconductors,Nanostructure,Material,Photocatalytic
更新于2025-09-23 15:22:29
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Guided wave inspection of dissimilar material joints using time reversal techniques
摘要： Dissimilar material bonding has recently gained a lot of attention in automotive, marine and defense applications. Nevertheless, a major hurdle limiting the full acceptance of such structural components is the lack of non-destructive evaluation (NDE) technique to evaluate their strength, which depends on the integrity of the bonding layer. In this work, guided wave (GW) inspection with surface-mounted piezoelectric sensors (PZT) was employed along with time reversal for Structural Health Monitoring (SHM) of dissimilar material lap-joints. Baseline-free probability imaging was used to identify the location of artificial disbond. The results of GW inspection were further validated with ultrasonic C-scan. Overall, the technique shows great potential in detection of defects in bonded joints.
关键词： guided waves,time reversal,diagnostic imaging,SHM,Dissimilar material joints
更新于2025-09-23 15:22:29
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Production of industry-specific quartz raw material using Sri Lankan vein quartz
摘要： High-purity quartz is a major raw material in many high-tech applications. Sri Lanka is rich in quartz mineralization, with an abundance of major vein quartz deposits with purity levels exceeding 99.5% SiO2. Developing high-tech products requires considerable capital investment, expertise, and advanced processing technologies which are lacking in developing countries like Sri Lanka. In most developing countries raw quartz with limited added value is exported to industrialized countries in grit and powder forms only after size reduction of run-of quarry quartz. We here examine an alternative approach, in which value addition is achieved by production of semi-processed and processed industry-specific quartz raw material for export. Chemical compositions of major types of vein quartz from seven vein quartz deposits and products of mass scale quartz processing at a plant located in the Badulla district of Uva Province, Sri Lanka were determined in study. Critical step evaluation in mining, transport and processing activities was carried out with reference to Fe and other critical trace elements, from data determined using inductively coupled plasma optical emission spectroscopy and atomic absorption spectroscopy. The results show that industrially critical trace element contents vary with type of quartz, association of accessory minerals, physical separation methods, transport practices, and comminution methods. We conclude that industry-specific quartz raw material can be produced through a combination of selective mining and exercising quality control during mining, transportation and processing activities.
关键词： Quartz,High-quality quartz,Quartz purification,Quartz raw material
更新于2025-09-23 15:22:29