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- 2019
- 2018
- infrared image
- target detection
- lucas–kanade method (LK)
- local contrast method (LCM)
- facet model
- target detection
- zero-crossing point
- Image processing
- Infrared camera
- Eye movement
- Optoelectronic Information Science and Engineering
- Chinese Academy of Sciences
- Gunma University
- University of Chinese Academy of Science
- Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Science
- University of Science and Technology of China
- Space Star Technology Co. LTD
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Zn <sub/>3</sub> Ga <sub/>2</sub> Ge <sub/>2</sub> O <sub/>10</sub> :Cr <sup>3+</sup> Uniform Microspheres: Template-Free Synthesis, Tunable Bandgap/Trap Depth, and <i>In Vivo</i> Rechargeable Near-Infrared-Persistent Luminescence
摘要： Near-infrared (NIR) emitting persistent phosphors of Cr3+-doped zinc gallogermanate have emerged for in vivo bio-imaging with the advantages of no need for in situ excitation. However, it is challenging to synthesize well-dispersed and uniform spherical particles with high brightness, high resolution, and distinguished NIR long afterglow. In this work, Zn3Ga2Ge2O10:Cr3+ (ZGGC) monospheres were directly synthesized by a facile hydrothermal method with the assistance of citric anions (Cit3-), which emit a NIR emission at ~696 nm and exhibit excellent NIR persistent luminescence with rechargeability. Controlled experiments indicated that the shape evolution of ZGGC product is significantly affected by Cit3-, solution pH, and the duration and temperature of hydrothermal reaction. Furthermore, compositional influence on the crystal structure, bandgap, trap depth, and luminescence characteristics of ZnyGa2Ge2O10-δ:Cr3+ (y = 2.8, 3.0, 3.2) were investigated in details, which allows to construct an energy level diagram of the ZGGC host, Cr3+ ions, and electron traps. It was found that the bandgap and conduction-band minimum (CBM) are significantly affected by the Zn content, while the valence-band maximum (VBM) is not. The y = 3.0 sample exhibited the best persistent luminescence, owing to its deepest defects. The ZGGC-NH2 prepared through surface functionalization of ZGGC spheres showed distinguished NIR long afterglow, low toxicity, and great potential for in vitro cell imaging and in vivo bio-imaging in the absence of excitation. Moreover, the persistent-luminescence signal from the ZGGC-NH2 can be repeated in vivo through in situ recharge with external excitation of a red LED lamp, indicating that the ZGGC-NH2 is suitable for applications in long-term in vivo imaging.
关键词： in vivo imaging,Near infrared persistent luminescence,conduction band minimum,monospheres
更新于2025-09-23 15:23:52
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Deeply subwavelength phonon-polaritonic crystal made of a van der Waals material
摘要： Photonic crystals (PCs) are periodically patterned dielectrics providing opportunities to shape and slow down the light for processing of optical signals, lasing and spontaneous emission control. Unit cells of conventional PCs are comparable to the wavelength of light and are not suitable for subwavelength scale applications. We engineer a nanoscale hole array in a van der Waals material (h-BN) supporting ultra-confined phonon polaritons (PhPs)—atomic lattice vibrations coupled to electromagnetic fields. Such a hole array represents a polaritonic crystal for mid-infrared frequencies having a unit cell volume of 10??λ?3 (with λ? being the free-space wavelength), where PhPs form ultra-confined Bloch modes with a remarkably flat dispersion band. The latter leads to both angle- and polarization-independent sharp Bragg resonances, as verified by far-field spectroscopy and near-field optical microscopy. Our findings could lead to novel miniaturized angle- and polarization-independent infrared narrow-band couplers, absorbers and thermal emitters based on van der Waals materials and other thin polar materials.
关键词： van der Waals material,near-field microscopy,phonon-polaritonic crystal,mid-infrared,hexagonal boron nitride,Bragg resonance
更新于2025-09-23 15:23:52
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<i>Spitzer Planck Herschel</i> Infrared Cluster (SPHerIC) survey: Candidate galaxy clusters at 1.3 < <i>z</i> < 3 selected by high star-formation rate
摘要： There is a lack of large samples of spectroscopically confirmed clusters and protoclusters at high redshifts, z > 1.5. Discovering and characterizing distant (proto-)clusters is important for yielding insights into the formation of large-scale structure and on the physical processes responsible for regulating star-formation in galaxies in dense environments. The Spitzer Planck Herschel Infrared Cluster (SPHerIC) survey was initiated to identify these characteristically faint and dust-reddened sources during the epoch of their early assembly. We present Spitzer/IRAC observations of 82 galaxy (proto-)cluster candidates at 1.3 < zp < 3.0 that were vetted in a two step process: (1) using Planck to select by color those sources with the highest star-formation rates, and (2) using Herschel at higher resolution to separate out the individual red sources. The addition of the Spitzer data enables efficient detection of the central and massive brightest red cluster galaxies (BRCGs). We find that BRCGs are associated with highly significant, extended and crowded regions of IRAC sources which are more overdense than the field. This result corroborates our hypothesis that BRCGs within the Planck–Herschel sources trace some of the densest and actively star-forming proto-clusters in the early Universe. On the basis of a richness-mass proxy relation, we obtain an estimate of their mean masses which suggests our sample consists of some of the most massive clusters at z ≈ 2 and are the likely progenitors of the most massive clusters observed today.
关键词： galaxies: star formation,submillimeter: galaxies,infrared: galaxies,galaxies: evolution,galaxies: clusters: general,galaxies: high-redshift
更新于2025-09-23 15:23:52
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Transparent wood bearing a shielding effect to infrared heat and ultraviolet via incorporation of modified antimony-doped tin oxide nanoparticles
摘要： Optically transparent wood (TW) is an emerging candidate for applications in energy efficient buildings. In this study, anti-ultraviolet and infrared heat shielding TW was prepared based on the delignification of the wood's substrate. This was followed by infiltration of pre-polymerized methyl methacrylate (PMMA) with modified antimony-doped tin oxide (ATO) nanoparticles. The ATO addition enhanced the interfacial bonding among the compounds, which improved the fracture strength, leading to a high fracture strength of 96.4 MPa and modulus of 4.27 GPa with addition of 0.3% ATO. Furthermore, the obtained ATO/TW exhibited high transparency, excellent near infrared (NIR) heat shielding performance, and ultraviolet (UV) shielding properties according to the ultraviolet–visible spectrophotometer measurement, the infrared heat shielding simulation test, and the UV-shielding test. The TW treated with 0.3% ATO still maintained a very low thermal conductivity of around 0.2 W m?1 K?1. After addition of 0.7% ATO, the obtained TW had a quite low UV transmittance of ＜20%. The Aspergillus niger maintained high viability after UV irradiation treatment when shielded with TW treated with 0.7% ATO. The findings indicate that the multifunctional and durable ATO/TW has a potential to be used as energy-saving building material.
关键词： A. Nano composites,A. Wood,B. Ultraviolet shielding,B. Infrared heat shielding
更新于2025-09-23 15:23:52
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A Novel Multilayer Sandwich Fabric-based Composite Material for Infrared Stealth and Super Thermal Insulation Protection
摘要： At present, infrared stealth materials for advanced detection and stealth technology is usually prepared with low emissivity coating on the surface, but there are very few efficient infrared stealth materials based on textiles with lightweight and flexible features. In this paper, we designed a carbon nanotube-doped aerogel (CNTAs) sandwich structure on polyimide (PI) fabric by hot pressing and then coated with a low emissivity Al-doped ZnO (ZAO) on the outer surface. The surface emissivity lower than 0.5 due to the existence of ZAO and the thermal conductivity of the intermediate interlayer aerogels as low as 0.013 W/(m?K). Additionally, through experiments, theoretical derivation and simulation analysis, we found the resultant composite demonstrated a high infrared stealth performance with super insulation effect, implying it will have a fine prospect in infrared stealth and thermal insulation protection fields with its unique structure and excellent properties.
关键词： Carbon Nanotube-doped Aerogel,Sandwich Structure,Infrared Stealth,Polyimide Fabric,Thermal Insulation,Al-doped ZnO
更新于2025-09-23 15:23:52
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Silver Nanostructures on Graphene Oxide as the Substrate for Surface-Enhanced Raman Scattering (SERS)
摘要： Nanosized surface-enhanced Raman scattering (SERS) substrates fabricated by the controlled growth of metal nanostructures on water-dispersed two-dimensional nanomaterials can open a new avenue for SERS analysis of liquid samples in biological fields. In this work, regular and uniform Ag nanostructures were grown on the surface of graphene oxide (GO) through a microwave-assisted hydrothermal method. Polyamidoamine (PAMAM) dendrimers were assembled on the surface of GO to form GO/PAMAM templates for growing Ag nanostructures, which are primarily comprised of Ag dimers and trimers. The prepared Ag/GO nanocomposites are highly dispersed and stable in aqueous solution and may be used as substrates for enhanced Raman detection of rhodamine 6 G (R6G) in aqueous solution. This special substrate provides high-performance SERS and suppresses R6G fluorescence in aqueous solution and is promising as a nanosized material for the enhanced Raman detection of liquid samples in biological diagnostics.
关键词： graphene oxide (GO),Surface-enhanced Raman scattering (SERS),polyamidoamine (PAMAM) dendrimers,transmission electron microscopy (TEM),Fourier transform infrared (FTIR) spectroscopy,rhodamine 6G (R6G)
更新于2025-09-23 15:23:52
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Local spatial correlation-based stripe non-uniformity correction algorithm for single infrared images
摘要： Stripe non-uniformity typically exists in infrared images and affects the visual effect; thus, eliminating stripe non-uniformity is essential to improve image quality. In this paper, a correction model with higher accuracy is developed. Unlike some other stripe non-uniformity correction methods using the same gain coefficient and offset parameters for the pixels of each column, different deviations of the correction parameters in the same column resulted by unsatisfactory preliminary non-uniformity correction are considered and are thought to be small and still relevant in space. The proposed method calculates the correction parameters for each pixel respectively based on the intrinsic spatial correlation between adjacent pixels in a column. What is more, an edge detection method is included. The experimental results indicate that the proposed algorithm effectively eliminates stripe noise of images of different scenes and it also works well in terms of preserving details. Furthermore, the algorithm exhibits high real-time performance.
关键词： De-striping,Spatial correlation,Non-uniformity correction,Stripe noise,Infrared imaging
更新于2025-09-23 15:23:52
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Graphene electrode diagnostic with IR imaging of Joule heat emission
摘要： Conductive graphene electrode of large area is required for some applications like for example photovoltaics or touch screens. Such large area graphene membrane needs specific test methods to assess defects which may obstacle its performance. In this work the infrared imaging of Joule heated graphene was proposed to estimate its uniformity and mechanical continuity. Thermal signatures of the typical mechanical defects like scratches and local resistivity inhomogeneity were identified. Distribution of the heat emission around such defects were simulated using finite elements method and then experimentally verified by recording of thermal landscape around the corresponding real graphene defects. Proposed method gives micrometric resolution and ability to inspection of large area electrodes depending on applied optics. Presented results give suggestions how graphene imperfections generate observed hot points related to graphene layer defects.
关键词： Finite elements,Joule heat,Defect,Graphene,Infrared
更新于2025-09-23 15:23:52
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Evolution of the infrared emissivity of Ni during thermal oxidation until oxide layer opacity
摘要： The mid-infrared (3–22 μm) emissivity of high-purity Ni has been studied in its pure state, during an isothermal oxidation in air at 730 °C and in the fully oxidized state. Measurements in pure Ni were performed in Ar between 200 and 800 °C and a change of slope in the temperature dependence of the total normal emissivity around its Curie temperature (354 °C) was observed. An oxidation process was carried out at 730 °C for 33 days, when the emissivity stopped evolving and the results were representative of NiO. During the ?rst stages, the emissivity evolved forming the usual interference patterns of semi-transparent ?lms. A mixture of oscillatory and monotonic behaviours of the emissivity as a function of wavelength and oxide layer thickness was found, which manifests as a non-trivial evolution of the total normal emissivity, di?erent than that reported in previous studies. Finally, the emissivity of NiO was measured from below its Néel temperature (252 °C) to 850 °C. It showed the typical shape of a ceramic material with an extra vibrational mode due to two-phonon processes and an additional absorption band around 5 μm in the antiferromagnetic phase produced by magnons. The temperature dependence of its total normal emissivity di?ers signi?cantly from that of a lightly oxidized nickel sample from the literature. Overall, the in?uence of the surface characteristics on the thermal radiative properties of oxidized Ni is thoroughly discussed and highlights the importance of accounting for all possible sources of infrared emissivity evolution in order to make accurate radiative heat transfer calculations.
关键词： Nickel oxide,Infrared emissivity,Radiometry,Radiative heat transfer,Magnetic phase transition,Nickel,Oxidation
更新于2025-09-23 15:23:52
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The near-to-mid infrared spectrum of quasars
摘要： We analyse a sample of 85 luminous (log (νLν(3 μm)/erg s?1) > 45.5) quasars with rest frame ～2–11 μm spectroscopy from AKARI and Spitzer. Their high luminosity allows a direct determination of the near-infrared quasar spectrum free from host galaxy emission. A semi-empirical model consisting of a single template for the accretion disc and two blackbodies for the dust emission successfully reproduces the 0.1–10 μm spectral energy distributions (SEDs). Excess emission at 1–2 μm over the best-fitting model suggests that hotter dust is necessary in addition to the ～1200 K blackbody and the disc to reproduce the entire near-infrared spectrum. Variation in the extinction affecting the disc and in the relative strength of the disc and dust components accounts for the diversity of individual SEDs. Quasars with higher dust-to-disc luminosity ratios show slightly redder infrared continua and less prominent silicate emission. We find no luminosity dependence in the shape of the average infrared quasar spectrum. We generate a new quasar template that covers the rest-frame range 0.1–11 μm, and separate templates for the disc and dust components. Comparison with other infrared quasar composites suggests that previous ones are less reliable in the 2–4 μm range. Our template is the first one to provide a detailed view of the infrared emission on both sides of the 4 μm bump.
关键词： infrared: galaxies,galaxies: active,quasars: emission lines,quasars: general
更新于2025-09-23 15:23:52