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oe1(光电查) - 科学论文

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出版时间
  • 2018
研究主题
  • Signal-to-Noise Ratio (SNR)
  • Infinite Gain Multiple Feedback (IGMF)
  • Visible Light Communications (VLC)
  • LED
  • Trans-Impedance Amplifier (TIA)
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • University of Northumbria
  • University of Huddersfield
221 条数据
?? 中文（中国） ▾

  • Effect of Toxic Metal Ions on Photosensitized Singlet Oxygen Generation for Photodegradation of Polyaromatic Hydrocarbon Derivatives and Inactivation of <i>Escherichia coli</i>

    摘要： Here we report an experimental study of the effect of toxic metal ions on photosensitized singlet oxygen generation for photodegradation of PAH derivatives, Anthracene-9,10-dipropionic acid disodium salt (ADPA) and 1,5-dihydroxynapthalene (DHN) and photoinactivation of E. coli bacteria by using cationic meso-tetra(N-methyl-4-pyridyl)porphine tetrachloride (TMPyP) as a singlet oxygen photosensitizer. Three s-block metals ions, such as Na+, K+, and Ca2+ and five toxic metals such as Cd2+, Cu2+, Hg2+, Zn2+, and Pb2+ were studied. The s-block metal ions showed no change of the rate of photodegradation of ADPA or DHN by TMPyP whereas a dramatic change in the photodegradation of ADPA and DHN were observed in the presence of toxic metals. The maximum photodegradation rate constants of ADPA and DHN were observed for Cd2+ ions [(3.91 ± 0.20) × 10-3 s-1 and (7.18 ± 0.35) × 10-4 s-1, respectively]. Strikingly, the photodegradation of ADPA and DHN was almost completely inhibited in the presence of Hg2+ ions and Cu2+ ions. A complete inhibition of growth of E. coli was observed upon visible irradiation of E. coli solutions with TMPyP and toxic metal ions particularly, Cd2+, Hg2+, Zn2+, and Pb2+ ions, except for Cu2+ ions where a significantly slow inhibition of E. coli’s growth was observed.

    关键词： E. coli,photodegradation,toxic metal ions,photosensitized singlet oxygen generation,PAH derivatives,TMPyP,photoinactivation

    更新于2025-09-23 15:21:01

  • NIR-Based Simultaneous Measurement of Amine Loading and Degree of Neutralization during Flotation Reagent Preparation for Potash Processing

    摘要： A continuous spectroscopy-based monitoring approach of the amine reagent preparation prior to flotation processing was investigated. The process involved the neutralization of a long carbon chain amine, C16-C20, with hydrochloric acid. Current methods of monitoring the degree of neutralization, controlling the HCl addition, and monitoring the amine content were based on pH measurements, with out-of-line sample lab-validation carried out using titration-based methods. Industry feedback indicated this method was prone to error and had resulted in challenges in process control. This work demonstrates a novel method of measuring both amine content and degree of neutralization using a mini-fluidic reactor and FT-NIR system equipped with a flow-through heated transmission cell. Analysis of the spectral response for wavenumbers in the range of 4,258-4,400 cm-1 yielded amine content and degree of neutralization measurements accurately to within ± 0.065 wt%, and ± 6.0% margin of errors, respectively. This led to monitoring intensification to increase KCl recoveries in flotation processing.

    关键词： Millet husk,Zinc ions,Sorption materials,Wastewater,Chitosan

    更新于2025-09-23 15:21:01

  • A luminescent probe for highly selective Cu2+ sensing using a lanthanide-doped metal organic framework with large pores

    摘要： Metal-organic frameworks (MOFs) are a class of porous coordination polymer. Recently, some studies have been focused on the detection of various analytes using luminescent MOFs. In this study, an MOF, Eu@1, is synthesized using ([Zn3(TAPB)2(CH3OH)2]) (1) as a precursor to encapsulate Eu3+. It has large pores and excellent luminescent properties, and the quantum yield is up to 30.2%, which can be used as a luminescent probe for highly selective Cu2+ sensing. It is simple and intuitive to use a lanthanide-doped MOF for highly sensitive sensing of Cu2+ by the change of emitting color (from red to blue). The inductively coupled plasma (ICP) and X-ray photoelectron spectroscopy (XPS) data indicate that Cu2+ can easily be exchanged with Eu3+ in 1D channels and replace a portion of the central ions. The good luminescent properties and visible color detectable to the naked eye demonstrate the potential application of this probe in colorimetric detection.

    关键词： ions exchange,metal organic framework,large pores materials,luminescence,colorimetric sensor

    更新于2025-09-23 15:21:01

  • Influence of Halide Ions on the Structure and Properties of Copper Indium Sulphide Quantum Dots

    摘要： In the synthesis of CuInS2 quantum dots (QDs), the halide ions present in the copper salts influence the QD growth and optical properties. X-ray absorption spectroscopy allowed rationalizing the halide incorporation in the lattice and the dependency of electronic properties of the material on the ion’s polarizability and interaction with hydrophobic moieties.

    关键词： optical properties,halide ions,CuInS2 quantum dots,X-ray absorption spectroscopy

    更新于2025-09-23 15:19:57

  • InP Quantum Dots-Based Electroluminescent Devices

    摘要： A metal-free, intermolecular syn-addition of hexamethyldisilane across simple alkenes is reported. The catalytic cycle is initiated and propagated by the transfer of a methyl group from the disilane to a silylium-ion-like intermediate, corresponding to the (re)generation of the silylium-ion catalyst. The key feature of the reaction sequence is the cleavage of the Si–Si bond in a 1,3-silyl shift from silicon to carbon. A central intermediate of the catalysis was structurally characterized by X-ray diffraction, and the computed reaction mechanism is fully consistent with the experimental findings.

    关键词： silylium ions,density functional calculations,homogeneous catalysis,alkenes,Si–Si activation

    更新于2025-09-23 15:19:57

  • Novel highly luminescent double-perovskite Ca2GdSbO6:Eu3+ red phosphors with high color purity for white LEDs: Synthesis, crystal structure, and photoluminescence properties

    摘要： High-efficiency red-emitting phosphors are required to fabricate high-performance white light-emitting diodes (LEDs). Herein, the novel highly efficient Eu3+-activated Ca2GdSbO6 double-perovskite red phosphors with good thermal stability toward warm-white LEDs were reported. A series of Ca2Gd(1-x)EuxSbO6 red phosphors with different Eu3+ doping concentrations (x = 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8) were synthesized by using high-temperature solid-state reaction method. Under the excitation of 396 nm near-ultraviolet light, these Ca2Gd(1-x)EuxSbO6 phosphors showed intense red emissions peaking at 612 nm due to the 5D0→7F2 transition of Eu3+ ions. The strongest luminescence intensity reached when Eu3+ doping concentration was x = 0.5, and the critical distance between Eu3+ activators was calculated to be 7.97 ?. The concentration quenching mechanism was due to the dipole-dipole interaction of Eu3+ ions. The CIE color coordinates of the optimal Ca2Gd0.5Eu0.5SbO6 phosphors were determined to be (0.6629, 0.3367), and the corresponding color purity reached about 94.9%. Importantly, the Ca2Gd0.5Eu0.5SbO6 phosphors revealed outstanding internal quantum efficiency of 73% and good thermal stability. The emission intensity of Ca2Gd0.5Eu0.5SbO6 phosphors at 423 K still remained about 73% of its initial value at 303 K. Finally, a prototype white LED device was fabricated by coating the phosphor blend of commercial blue-emitting BaMgAl10O17:Eu2+ and our as-prepared red-emitting Ca2Gd0.5Eu0.5SbO6 on a 395 nm LED chip. Under 20 mA driven current, the device showed bright warm-white light with CIE color coordinates of (0.3888, 0.3943), correlated color temperature of 3911 K, and color rendering index of 88.4. The results demonstrated that the developed novel red-emitting Ca2Gd0.5Eu0.5SbO6 phosphors could be used as potential color converters in white LEDs.

    关键词： White LEDs,Photoluminescence,Ca2GdSbO6,Double-perovskite,Eu3+ ions,Red-emitting phosphors

    更新于2025-09-23 15:19:57

  • The Tvs of Tomorrow: How RCA's Flat-Screen Dreams Led to the First Lcds

    摘要： The Optimized Energy Degrading Optics (OEDO) beamline is an upgrade of the High-resolution beamline at the RI Beam Factory at RIKEN. Its purpose is to measure nuclear reactions induced by radioactive ions at 10–50 MeV/u. The main components of the OEDO beamline are two superconducting quadrupole triplet magnets and one radio-frequency deflector, which were recently installed. This setup produces slowed-down, well-focused radioactive-isotope beams by using a degree of freedom in the longitudinal phase space of the beam. This paper describes the OEDO beamline in detail, discusses the unique concept of its ion optics, and demonstrates its feasibility by conducting measurements with medium-mass radioactive-isotope beams.

    关键词： RI Beam Factory,radioactive ions,superconducting quadrupole triplet magnets,OEDO,nuclear reactions,radio-frequency deflector

    更新于2025-09-23 15:19:57

  • [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) - Fabrication and Characterization of New Phosphate Glasses and Glass-Ceramics Suitable for Drawing Optical and Biophotonic Libers

    摘要： Rare earth doped phosphate glasses are attractive materials for the engineering of photonic devices, due to their easy processing, good thermal stability, excellent optical properties and high rare-earth ions solubility [1]. Besides, phosphate glasses with a P2O5 content of 50 mol% have been shown to be suitable for fiber drawing. It is well known that if the rare-earth ions are located in crystalline phase of desired nature and structure, the spectroscopic properties of the glasses can be enhanced [2]. Therefore, efforts have been focused on the development of new glass-ceramics (GCS) obtained from the heat treatment of glasses, as these engineered materials possess some of the glass properties (large flexibility of composition and geometry) but also some advantages of the RE-doped single crystals (high absorption and emission as well as long lifetimes). In this presentation, we will first discuss how new active phosphate glasses can be prepared with a bioactivity functionality and their composition tailored to enhance their spectroscopic properties. We will show that the heat treatment does not necessarily lead to the bulk precipitation of rare-earth doped crystals (see figure 1). Therefore, we will present a new route to prepare rare-earth doped crystals containing glasses using the direct doping method (schematic presented in Figure 2). We will review the main challenge with this novel route of preparing glasses, related to the survival and dispersion of the particles in the glasses. Finally, we will demonstrate that some of the promising glasses can be drawn into optical fibers with broad luminescence over 70 nm of bandwidth and also into biophotonic fiber in the prospect of developing an innovative biosensor.

    关键词： glass-ceramics,biophotonic fibers,phosphate glasses,rare-earth ions,optical fibers

    更新于2025-09-23 15:19:57

  • Quantum Dot-Based Hybrid Coacervate Nanodroplets for Ultrasensitive Detection of Hg2+

    摘要： Multifunctional organic-inorganic hybrid materials with inherent optical, electrical and/or magnetic properties find tremendous importance in various fields such as sensing, photovoltaics, therapeutics, bio-imaging, and light-emitting devices. Herein, we have fabricated membrane-free organic-inorganic hybrid luminescent coacervate nanodroplets and utilized them towards ultrasensitive detection and efficient removal of mercuric ions (Hg2+) simultaneously. The self-assembly of negatively charged mercaptosuccinic acid (MSA)-capped CdTe quantum dots (QDs) in the presence of positively charged poly(diallyldimethylammonium chloride) (PDADMAC) leads to the formation of luminescent nanodroplets with average size of 430 ± 20 nm. Selective luminescence quenching of these nanodroplets has been observed only in the presence of Hg2+. It has also been observed that the presence of other metal ions does not interfere in the sensing process. Our findings reveal that Hg2+ ions specifically associate with the porous structure of these nanodroplets via electrostatic interactions with the free carboxylate groups of MSA ligands at the surface of CdTe QDs and undergo photoinduced electron transfer (PET) with photoexcited QDs. The limit of detection (LOD) for Hg2+ sensing with our present system is estimated to be 1.32 nM (0.26 ppb), which is significantly lower than most of the earlier reported self-assembled materials. Moreover, these hybrid nanodroplets efficiently sequester trace quantity of Hg2+ from contaminated water. The overall performance of our present system towards Hg2+ remediation is superior over most of the earlier reported hybrid nanocomposites in terms of fast uptake kinetics (within 15 min), ultrasensitive detection (LOD: 0.26 ppb), and high sequestration efficiency (98.3%). Our present findings in particular, the tailorability of surface ligands and inorganic nanoparticles in hybrid nanodroplets provide great advantage for the development of multifunctional nanomaterials for diverse range of applications.

    关键词： membrane-free nanodroplets,detection of mercuric ions,sensing,LOD,hybrid nanodroplets

    更新于2025-09-23 15:19:57

  • DNA enzyme mediated ratiometric fluorescence assay for Pb(II) ion using magnetic nanosphere-loaded gold nanoparticles and CdSe/ZnS quantum dots

    摘要： Based on the inner filter effect mechanism of quantum dots, a ratiometric fluorescence nanoprobe was constructed for the determination of Pb(II) ion. Green emitting quantum dots conjugated with DNA substrate (DNA2) acted as donors providing green fluorescence, while gold nanoparticles coupled with DNA enzyme (DNA1) as acceptors quench the green fluorescence. Meanwhile, Fe3O4 nanosphere served as magnetic substrates to facilitate separation process and red fluorescence as an “inner rule” to eliminate the background signal. In the presence of Pb(II) ion, the DNA1 specifically recognize and capture Pb(II) ion with enhanced catalytic activity, which can cleave DNA2 and “turn on” the green fluorescence (I540), while the red fluorescence (I630) remained unchanged. In this way, the ratio of I540/I630 reflects the Pb(II) ion in the system, enabling the quantitative and selective determination of Pb(II) ion over nine different metal ions. Under optimal conditions, the ratiometric fluorescence assay showed good linearity (R2 = 0.98) within the range 10 to 100 ng mL?1. The limit of detection (LOD) was calculated to be 1.79 pg mL?1 (S/N = 3, n = 3, ±3.8%). The proposed fluorescence nanoprobe provides better sensitivity and accuracy than non-ratiometric signal evaluation for Pb(II) ion determination.

    关键词： Fluorescence nanoprobe,Inner rule,Magnetic separation,Tea sample,Metal ions,Inner filter effect

    更新于2025-09-23 15:19:57