修车大队一品楼qm论坛51一品茶楼论坛,栖凤楼品茶全国楼凤app软件 ,栖凤阁全国论坛入口,广州百花丛bhc论坛杭州百花坊妃子阁

oe1(光电查) - 科学论文

过滤筛选

出版时间
  • 2019
  • 2018
研究主题
  • infrared image
  • target detection
  • lucas–kanade method (LK)
  • local contrast method (LCM)
  • facet model
  • target detection
  • zero-crossing point
  • Sulfurization
  • CVD
  • MoS2
应用领域
  • Optoelectronic Information Science and Engineering
  • Nanomaterials and Technology
机构单位
  • Chinese Academy of Sciences
  • Indian Institute of Technology Jodhpur
  • 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
208 条数据
?? 中文（中国） ▾

  • Color Tunable Pigments with high NIR reflectance in Terbium doped Cerate systems for Sustainable Energy Saving Applications

    摘要： Color tunable pigments from yellow to red hues were developed in Tb doped A2CeO4 (A = Sr and Ba) system by the conventional ceramic route. The developed pigments were analysed for their phase purity, chemical oxidation state, elemental analysis, morphology and optical properties by various advanced techniques. The Ba substitution in Sr2-xCe0.6Tb0.4O4 gently shifts the absorption edge to higher wavelengths producing bright yellows to reddish orange colors whereas, the Tb substitution in Ba2Ce1-xTbxO4 allows abrupt shift in the absorption edge to longer wavelengths leading to intense red hues. The chemical oxidation state analysis indicates the modifications of Tb3+ concentrations in both the environments due to metal to metal charge transfer transitions induced by lattice expansion. Typically the compositions SrBaCe0.6Tb0.4O4 (yellow; b* = 75.36, R = 91%) and Ba2Ce0.4Tb0.6O4 (red; a* = 30.09, R = 89%) exhibit brilliant coloristic and reflectance properties. The applicability studies revealed good coloring performance in the polymer matrix and on concrete slab with high solar reflectance. Further, the pigments are proven to be weather resistant in acid/alkali/moisture atmospheres with good thermal stability. These color characteristics with high solar reflectance of sustainable and eco-friendly compositions make them promising colorants for exterior coating formulations to mitigate the cooling energy consumption.

    关键词： Yellow and Red pigments,Cerium,Terbium,Solar reflectance

    更新于2025-11-21 11:18:25

  • Development of naphthalimide-functionalized thermochromic conjugated polydiacetylenes and their reversible green-to-red chromatic transition in the solid state

    摘要： Development of PDAs has received great attention in many fields due to their optical and chromatic properties towards external stimuli. In this article, two novel PDAs (NPI-PDA1 and NPI-PDA2) containing naphthalimide as a head group are designed and synthesized through self-assembly followed by topochemical polymerization, and these compounds show a reversible green-to-red colorimetric transition upon heating. PEO-embedded films are fabricated to facilitate the investigation of the thermochromic properties, and the surface morphologies of the films are observed by SEM analysis. The thermochromic behavior and color transitions are observed using photography and electronic absorption spectroscopy. The changes in the extended ene-yne conjugated system of the polymer during heat treatment are successfully monitored by Raman spectrometry. Moreover, PDA-embedded crayon wax-based hand-writable pens are fabricated and used efficiently on a solid substrate. NPI-PDA1 and NPI-PDA2 display excellent reversibility in the temperature ranges of 25–120 °C and 25–160 °C, respectively in the PEO polymer and paraffin wax matrices.

    关键词： Thermochromism,PEO films,Green-to-red color transition,Polydiacetylene,Crayon pen

    更新于2025-11-21 10:59:37

  • Highly efficient rare-earth-free deep red emitting phosphor La <sub/>2</sub> Li <sub/>1?y</sub> Sb <sub/>1?x</sub> O <sub/>6</sub> : <i>x</i> Mn <sup>4+</sup> , <i>y</i> Mg <sup>2+</sup> : application in high-power warm w-LEDs

    摘要： Phosphor-in-glass (PiG), which serves as both a luminescent convertor and organic encapsulation material in high-power white light-emitting diodes (w-LEDs), has become a prospective research hotspot owing to its high transparency and thermal stability. However, YAG:Ce3+ PiG-based LED devices still suffer from a lack of a red component. Therefore, the development of red phosphors with excellent quantum efficiency and superior thermal stability is urgent. Herein, a highly efficient La2Li1?ySb1?xO6:xMn4+,yMg2+ red phosphor with a broadband emission ranging from 670 to 720 nm was fabricated via a conventional solid-state reaction. By co-doping Mg2+ in La2LiSbO6:Mn4+, the emission intensity was enhanced significantly, which reaches as high as 10 times that of the single-doped La2LiSbO6:Mn4+. It is proposed that the Mg2+ dopant can compensate imbalanced charges for the substitution of Sb5+ by Mn4+ and interrupt adverse energy transfer among the Mn4+ activators. Impressively, a maximum quantum yield of up to 80.3% is achieved and about 80% emission intensity is retained at the temperature of 423 K. Furthermore, the crystal field strength (Dq) and Racah parameters (B and C) together with the nephelauxetic ratio (b1) were calculated based on the obtained spectroscopic data. By embedding the red-emitting La2LiSbO6:Mn4+,Mg2+ phosphor and yellow-emitting YAG:Ce3+ phosphor into TeO2-based glass, an inorganic PiG composite as a color converter to replace organic silicone was acquired. The excellent optical parameters and tunable chromaticity feature of the fabricated w-LEDs were achieved by adjusting the mass ratio of La2LiSbO6:Mn4+,Mg2+ to YAG:Ce3+ in the PiG plate, where the correlated color temperature changed from cool white (6555 K) to warm (4130 K) and the color rendering index increased from 73.7 to 86.6 under an operating current of 300 mA.

    关键词： Phosphor-in-glass,quantum yield,red phosphor,Mg2+,thermal stability,w-LEDs,Mn4+

    更新于2025-11-20 15:33:11

  • Novel Ca2GdTaO6:Mn4+,M (M = Li+, Na+, K+, and Mg2+) red phosphors for plant cultivation light-emitting diodes: Synthesis and luminescence properties

    摘要： Recently, Mn4+-activated red phosphors are becoming potential color converters for application in indoor plant cultivation light-emitting diodes, owing to their satisfactory luminescence properties as well as low cost. Herein, novel Mn4+-activated double perovskite-type Ca2GdTaO6 phosphors have been synthesized by a high-temperature solid-state reaction method in air, which exhibited a broad excitation band with two peaks locating at 355 nm and 496 nm in range of 250-600 nm and had an intense red emission peaking at 676 nm due to Mn4+:2Eg→4A2g spin-forbidden transition ranging from 650 to 750 nm under 355 nm excitation. Concentration-dependent luminescence properties were studied. The optimal Mn4+ doping concentration in Ca2GdTaO6 host was 0.004, and the concentration quenching mechanism was determined to be a dipole-dipole interaction among Mn4+ ions. Furthermore, the Ca2GdTaO6:0.004Mn4+ phosphor possessed the internal quantum efficiency up to 33% when excited at 355 nm. Besides, the decay lifetimes of Ca2GdTaO6:Mn4+ presented a reasonable downward trend with increasing Mn4+ concentration. In addition, the effect of charge compensation (co-doping of Li+, Na+, K+, and Mg2+ ions) on the luminescent properties of Ca2GdTaO6:Mn4+ phosphors was also investigated.

    关键词： Indoor plant cultivation,Ca2GdTaO6,Mn4+,Double perovskite,Luminescence properties,Red phosphor

    更新于2025-11-20 15:33:11

  • Novel BODIPY-based fluorescent probes with large Stokes shift for imaging hydrogen sulfide

    摘要： Hydrogen sulfide has important biomedical significance because it plays a regulatory role in a variety of physiological processes. In our previous work, we investigated the effect of substituents on Stokes shift of BODIPY and found that methoxy groups on phenyl substituents at 3,5-positions could expand the Stokes shift of BODIPY-based probes. In this study, taking hydrogen sulfide (H2S) as analyte, we designed and synthesized 4,4-difluoro-8-{4-(2,4-dinitrophenoxy)phenyl}-3,5-bis(2,4-dimethoxyphenyl)-4-bora-3a,4a-diaza-s-indancene (DMOEPB) and 4,4-difluoro-8-(4-nitrophenyl)-3,5-bis(2,4-dimethoxyphenyl)-4-bora-3a,4a-diaza-s-indancene (DMONPB) according to the same strategy. As expected, Stokes shifts of 49 nm and 51 nm were obtained respectively, which demonstrate the feasibility of the strategy in the synthesis of other fluorescent probes for the detection of small biomolecules. DMONPB can react with H2S to form the derivative with a fluorescence quantum yield of 0.13. An excellent linear relationship was observed in the range of H2S concentrations from 0 μM to 800 μM and the detection limit was 1.3 μM. Furthermore, it can be successfully applied to imaging of H2S in cells and tissues. For DMOEPB, the presence of m-dinitrophenyl did not cause the expected fluorescence quenching, which makes it impossible to perform bioimaging. We speculate that the strong electron-withdrawing property of nitro group is obviously weaker when the two benzene rings are separated at 8-position and are not conjugated with the fluorophore. It provides experience and lessons for designing the same type of turn-on probe.

    关键词： hydrogen sulfide,BODIPY,red fluorescence,bioimaging,large Stokes shift

    更新于2025-11-19 16:46:39

  • Alcohol-Guided Growth of Two-Dimensional Narrow-Band Red-Emitting K2TiF6:Mn4+ for White Light-Emitting Diodes

    摘要： The use of red phosphors with low light-scattering loss could improve the luminous efficacy and color rendering of white light-emitting diodes (LEDs). Thus, the discovery of such phosphors is highly desired. In this work, high-efficiency two-dimensional red-emitting K2TiF6:Mn4+ (KTFM) were synthesized via an alcohol-assisted coprecipitation route. The synergistic effects of 1-propanol and hydrofluoric acid (HF) on the growth of KTFM microsheets (MSs) were studied through the first-principles calculations, which revealed that 1-propanol promoted the growth of KTFM MSs by preferentially adsorbing on the H-terminated K2TiF6 (001) surface. The photoluminescence quantum efficiency (QE) of Mn4+-activated K2TiF6 MSs was highly related to their size and thickness. The morphology-optimal KTFM MSs presented high internal QE (> 90 %), external QE (> 71%), and thermal quenching temperature (102% at 150 °C relative to that at 25 °C). A prototype phosphor-converted LED with KTFM as the red-emitting component showed an excellent color rendition (Ra = 91, R9 = 79) and high luminous efficacy (LE =156 lm/w).

    关键词： light emitting diode,two-dimensional material,Narrow band,K2TiF6:Mn4+,backlight,red emission

    更新于2025-11-14 17:04:02

  • Simultaneous enhancement of red upconversion luminescence and CT contrast of NaGdF <sub/>4</sub> :Yb,Er nanoparticles <i>via</i> Lu <sup>3+</sup> doping

    摘要： To date, lanthanide-doped upconversion nanoparticles (UCNPs) have been widely reported as a promising CT contrast agent because they have high atomic numbers and big X-ray attenuation coefficient values. However, it is still a challenge to fabricate a simple multimodal imaging probe with improved image quality for early cancer diagnosis in clinical medicine. Herein, ultra-small, uniform and monodisperse β-NaGdF4:Yb,Er,X% Lu (X = 0, 1, 2.5, 4, 6, 7.5) UCNPs were prepared through a solvothermal method with high-level modulation of both the phase and morphology. Meanwhile, a remarkably enhanced red upconversion luminescence (UCL) in the β-NaGdF4:Yb,Er,X% Lu NPs was successfully realized via Lu3+ doping. It is found that as the content of Lu3+ increases from 0 to 7.5 mol%, the UCL intensity of the red emission first increases and then decreases, with the optimum doping content of Lu3+ ions of 2.5 mol%. The red UCL enhancement is ascribed to the change of the Yb–Er interionic distance controlling the Yb–Er energy transfer rate and the distortion of the local environment of Er3+ ions influencing the 4f–4f transition rates of Er3+ ions, which has been further confirmed by the experimental check of the crystallographic phase and by photoluminescence spectroscopy employing Eu3+ as the structural probe, respectively. More importantly, after being modified with the HS-PEG2000-NH2 ligand, the NH2-PEGylated-NaGdF4:Yb,Er,X% Lu NPs exhibited low cytotoxicity, high biocompatibility, and remarkably enhanced contrast performance in in vitro UCL and in vivo CT imaging. On the basis of our findings, the as-obtained functionalized UCNPs could be considered as a promising versatile dual-mode imaging probe for bioimaging, tumor diagnosis, and cancer therapy.

    关键词： red luminescence enhancement,Lu3+ doping,upconversion nanoparticles,multimodal imaging,CT contrast

    更新于2025-11-14 17:04:02

  • Self-assembling Non-conjugated Poly(amide-imide) into Thermoresponsive Nanovesicles with Unexpected Red fluorescence for Bioimaging

    摘要： Non-conjugated red fluorescent polymers have been increasingly studied to improve the biocompatibility and penetration depth over conventional fluorescent materials. However, the accessibility of such polymers remains challenging due to the scarcity of non-conjugated fluorophores and lacking relevant mechanism of red-shifted fluorescence. Herein, we discovered that the combination of hydrogen bonding and π-π stacking interactions provides non-conjugated poly(amide-imide) with a large bathochromic shift (> 100 nm) from blue-green fluorescence to red emission. The amphiphilic PEGylated poly(amide-imide) derived from in-situ PEGylation self-assembled into nanovesicles in water, which isolated the aminosuccinimide fluorophore from the solvents and suppressed the hydrogen bonds formation between aminosuccinimide fluorophores and water. Therefore, the fluorescence of PEGylated poly(amide-imide) in water was soundly retained. Furthermore, the strong hydrogen bonding and hydrophobic interactions with water provided PEGylated poly(amide-imide) with a reversible thermoresponsiveness and presented a concentration-dependent behavior. Finally, accompanied with the excellent biostability and photostability, PEGylated poly(amide-imide) exhibited as a good candidate for cell imaging.

    关键词： poly(amide-imide),red-shifted fluorescence,self-assembly,bioimaging,nanovesicles

    更新于2025-11-14 17:04:02

  • Far-Red Spectrum of Second Emerson Effect: A Study Using Dual-Wavelength Pulse Amplitude Modulation Fluorometry

    摘要： Non-additive enhancement of the photosynthesis excited by simultaneous illumination with far-red light and light of shorter wavelengths is called as “second Emerson effect”. Its action spectra are well-known as a photosynthetic yield’s dependence on light wavelength in red (630-690 nm) spectral region at a constant-wavelength far-red illumination near 700-715 nm. However, the opposite dependence of the photosynthetic yield’s of shorter constant-wavelength light (red or blue) on light wavelength in far-red (690-760 nm) spectral region was never studied. In this study the action spectrum of second Emerson effect was studied using a fast-Fourier dual-wavelength Pulse Amplitude Modulation (PAM) fluorometry. Chlorophyll fluorescence in ailanthus (Ailanthus altissima Mill.) leaves was excited with blue modulated light. Far-red induced decrease of fluorescence (fluorescence shift-FRIFS) was studied in response to illumination of leaves with a background light from 690 to 760 nm (10 nm step), calculating FRIFS = (F0-Fs)/F0, where F0-fluorescence measured without and Fs-with far-red light. Maximum FRIFS was observed at 720 nm (11.8%), but it still remained considerable at 740, 750 nm and a low FRIFS values were revealed at 690 and even at 760 nm. Measurements carried out with blue saturating flashes during and after far-red illumination showed the increase of quantum yield of Photosystem II (PSII), calculated as Fv/Fm at 720 nm background light. FRIFS had lower values under excitation with red modulating light. It is concluded that FRIFS is a result of a photochemical quenching caused by an additional selective far-red excitation of PSI in conditions when PSII is preferably excited by blue light thus leading the PSI to limit non-cyclic electron flow. The contradiction between the known absorption spectra of PSI-light harvesting complex I and the observed action spectrum of second Emerson effect (FRIFS spectrum) is discussed.

    关键词： Photosystem II,Ailanthus Altissima,Photosystem I,Second Emerson Effect,Fast-Fourier PAM-Fluorometry,Far-Red Light,Thylakoid Electron Transport

    更新于2025-11-14 15:30:11

  • Upconversion fluorescent nanoparticles based-sensor array for discrimination of the same variety red grape wines

    摘要： In this research, a novel fluorescent sensor array based on upconversion nanomaterials (UCNPs) for the discrimination of the same variety red grape wines from different manufacturers was developed. The sensor array was composed of six elements: one positively charged UCNPs modified with guanidine groups (UCNPs@GDN), two negatively charged UCNPs modified with sulfonic acid groups (UCNPs@SO3H) and phosphonic acid groups (UCNPs@PO(OH)2), respectively, and their mixture 1 (UCNPs@GDN + UCNPs@SO3H), mixture 2 (UCNPs@GDN + UCNPs@PO(OH)2) and mixture 3 {UCNPs@GDN + UCNPs@SO3H + UCNPs@PO(OH)2}. The discrimination mechanism is mainly attributed to the emission of those upconversion fluorescent nanoparticles being quenched by organic ingredients that usually exist in red grape wines. The discrimination of red grape wines was carried out by employing UCNPs@GDN, UCNPs@SO3H and UCNPs@PO(OH)2 in pH = 7.0 HEPES buffer, the mixture 1 and mixture 2 in pH = 9.0 PBS buffer, and mixture 3 in pH = 6.0 Tris–HCl buffer. Principal component analysis (PCA) of the data obtained from our established array showed obvious distinction among the nine red grape wines from different manufacturers. The present work is expected to inspire more marvellous research in the fields of UCNPs and red grape wines identification.

    关键词： red grape wines,fluorescence quenching,sensor array,upconversion nanoparticles,discrimination

    更新于2025-11-14 15:18:02