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Synthesis, Crystal Structure and Fluorescent Property of a Onedimensional Coordination Polymer Constructed By 1,3-Bis(1,2,4-Triazol-1-Ylmethyl)- Benzene And 4,4′-Oxydiphthalic Acid
摘要： A one-dimensional Cd(II) complex [Cd(H3ODPT)2(MBTZ)2?2H2O]n (1) (MBTZ = 1,3-bis(1,2,4-triazol-1-yl-methyl)benzene, H4ODPT = 4,4′-oxydiphthalic acid) is synthesized and characterized using single crystal X-ray diffraction, IR spectroscopy, and elemental analysis. Single crystal X-ray diffraction analysis reveals that complex 1 is a one-dimensional double chain polymer containing 24-membered rings with MBTZ ligands as the bridges arranged parallel to the b crystal direction, while the singly deprotonated H4ODPT ligands are extended on both sides of such double chains. In addition, the luminescence measurements reveal that complex 1 exhibits strong fluorescent emission in the solid state at room temperature.
关键词： 4,4′-oxydiphthalic acid,1,3-bis(1,2,4-triazol-1-ylmethyl)benzene,fluorescent property,Cd(II) complex,crystal structure
更新于2025-09-23 15:23:52
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Glint Removal Assessment to Estimate the Remote Sensing Reflectance in Inland Waters with Widely Differing Optical Properties
摘要： The quality control of remote sensing reflectance (Rrs) is a challenging task in remote sensing applications, mainly in the retrieval of accurate in situ measurements carried out in optically complex aquatic systems. One of the main challenges is related to glint effect into the in situ measurements. Our study evaluates four different methods to reduce the glint effect from the Rrs spectra collected in cascade reservoirs with widely differing optical properties. The first (i) method adopts a constant coefficient for skylight correction (ρ) for any geometry viewing of in situ measurements and wind speed lower than 5 m·s?1; (ii) the second uses a look-up-table with variable ρ values accordingly to viewing geometry acquisition and wind speed; (iii) the third method is based on hyperspectral optimization to produce a spectral glint correction, and (iv) computes ρ as a function of wind speed. The glint effect corrected Rrs spectra were assessed using HydroLight simulations. The results showed that using the glint correction with spectral ρ achieved the lowest errors, however, in a Colored Dissolved Organic Matter (CDOM) dominated environment with no remarkable chlorophyll-a concentrations, the best method was the second. Besides, the results with spectral glint correction reduced almost 30% of errors.
关键词： remote sensing accuracy,inland waters,optically complex systems
更新于2025-09-23 15:23:52
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Electron-phonon interactions in subband excited photoluminescence of hexagonal boron nitride
摘要： The h-BN microcrystalline powder with carbon and oxygen impurities have been studied at 83 and 296 K using Raman and photoluminescence (PL) spectroscopies. The observed blue shift of Raman peaks with temperature decreasing have been discussed allowing for the enhanced role of the optical vibrational modes. Two series of phonon replicas in PL emission spectra with a zero-phonon line at 4.08 eV have been registered under 4.28 eV excitation. The energy levels model of the impurity (CN-ON)-complex responsible for observe luminescence was proposed. It was shown that the optically active center retains its electroneutrality in the processes of radiative recombination under subband (in 4.28 eV) or band-to-band excitation. Possible mechanisms of electron-phonon scattering and phonon replicas forming under subband excitation of (CN-ON)-complex were analyzed. It was substantiated that the longitudinal optical (?ωLO = 174 meV) and transverse acoustic (?ωTA = 60 meV) phonons at the middle points of high symmetry in the first Brillouin zone participate in the processes of intravalley (M- and Κ-scattering) and intervalley (Κ → Μ)-scattering, respectively.
关键词： ultraviolet luminescence,intravalley scattering,point defect,intervalley scattering,phonon replicas,h-BN,carbon-oxygen complex
更新于2025-09-23 15:23:52
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An isogeometric analysis to identify the full flexoelectric complex material properties based on electrical impedance curve
摘要： In this paper, we present a new approach to identify all material parameters of flexoelectric materials based on electrical impedance curves. This approach combines an Isogeometric Analysis (IGA) formulation with a gradient-based optimization algorithm using the Method of Moving Asymptotes (MMA). The IGA formulation allows for efficient modeling of flexoelectricity taking advantage of the higher order continuity of IGA. The proposed methodology starts with determining preliminary real parts based on resonant modes in order to avoid local minima which gives the numerical impedance curves close to the experimental impedance curve. The results in the preliminary step are used as initial parameters of the refinement step to simultaneously determine both real and imaginary part by minimizing the difference between pseudo-experimental and numerical impedance curve. Some numerical examples are illustrated to show the good agreement between the numerical and pseudo-experimental impedance curves.
关键词： Complex parameters,Piezoelectric material,Flexoelectric material,Isogeometric analysis
更新于2025-09-23 15:23:52
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New blue phosphorescence from trifluorosulfonyl-substituted iridium complexes
摘要： For color-pure phosphorescence organic light emitting diodes (PHOLEDs), we synthesized the trifluoromethyl sulfonyl substituted ligand and two new blue Iridium complexes with perfluoro-sulfonyl group (SOCF3pic and SOCF3mpic). The both iridium complexes showed similar photophysical and thermal properties while the HOMO energy leves of two Iridium complexes slightly differnet to be -5.84 eV for SOCF3pic and -5.74 eV for SOCF3mpic, respectively. The device with the SOCF3mpic dopant exhibited higher device efficiencies of 7.17 cd/A and 3.7 % compared to that with the SOCF3pic dopant (4.03 cd/A and 2.78 %). Two-dimensional GIXD images of scattered X-ray intensity from surface to full depth for SOCF3pic-doped and SOCF3mpic-doped TCTA:4PTPS films were characterized for preferential orientation along the out-of-plane direction.
关键词： preferential orientation along the out-of-plane direction,blue phosphorescence,iridium complex,grazing incidence wide-angle X-ray diffraction,organic light emitting diodes
更新于2025-09-23 15:23:52
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Improved reflection technique for the permittivity measurement of ferrites using slotted coaxial samples
摘要： This paper presents the effect of magnetic permeability on the permittivity measurement using coaxial line reflection technique. It discusses in detail about the design aspects, analysis and simulation of the slotted co-axial sample and fixture for dielectric characterization of the ferrites and garnets possessing both dielectric and magnetic properties. This technique makes use of improved coaxial fixture and APC 07 compatible slotted coaxial sample geometry to measure the complex permittivity of the ferrite material. Permittivity is calculated from the impedance of sample loaded fixture, which is independent of magnetic permeability, because of air slot cut in the coaxial hollow cylindrical sample along the length. Characterization data of dielectrics and ferrites is used in design of ferrite circulators, and pulse magnets for particle accelerator applications. This is also used in many other RF applications including design of dielectric resonator for spin wave line width measurement of ferrites. Design work is aimed at accurate measurement of complex permittivity; using reflection measurement in coaxial fixture over a wide frequency range of 20 kHz to 1 GHz. Reflection measurement technique is further explored for accurate measurement of complex permittivity.
关键词： Complex permittivity,Network analyzer,Coaxial open ended fixture,Wide band measurement technique
更新于2025-09-23 15:23:52
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Structural, optical, electrical and thermal characteristics of La{CS(NH2)2CO(NH2)2}Cl3 : A novel hybrid complex for optoelectronic applications
摘要： A hybrid complex of lanthanum chloride with urea and thiourea is crystallized at room temperature by conventional solution method. The structural investigations by single crystal X-ray diffraction confirmed the orthorhombic system with cell dimensions a = 7.676 ?, b = 8.564 ?, c = 5.498 ?, α = β = γ = 90°. The optical studies by UV–VIS absorption spectroscopy shows the complex exhibits transmittance about 96%. The complex is characterized as the wide band gap crystals with value greater than 4 eV. The dielectric properties were studied in frequency range 10 kHz–1 MHz in temperature range 303–453 K. The ac conductivity was found to obey the universal power law and suggests the correlated barrier hoping mechanism dominating the conduction process. The thermal stability and the decomposition mechanism were confirmed by thermo gravimetric and differential thermo analytical (TG/DTA) techniques.
关键词： Dielectric analysis,ac conductivity,Hybrid complex,X-ray diffraction,UV–Vis spectrum
更新于2025-09-23 15:23:52
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Strong Emission Enhancement in pH-Responsive 2:2 Cucurbit[8]uril Complexes
摘要： Organic fluorophores, particularly stimuli-responsive molecules, are very interesting for biological and material sciences applications, but limited by aggregation- and rotation-caused photoluminescence quenching. A series of easily accessible bipyridinium fluorophores is reported, whose emission is quenched by a twisted intramolecular charge transfer (TICT) mechanism. Encapsulation in a cucurbit[7]uril host yields a 1:1 complex exhibiting a moderate emission increase due to destabilization of the TICT state inside the apolar cucurbituril cavity. A much stronger fluorescence enhancement is observed in 2:2 complexes with the larger cucurbit[8]uril, which is caused by additional conformational restriction of rotations around the aryl-aryl bonds. As the cucurbituril complexes are pH switchable, this system represents an efficient supramolecular ON/OFF fluorescence switch.
关键词： restriction of intramolecular motion,luminescence,host-guest complex,fluorescence enhancement,Cucurbituril
更新于2025-09-23 15:23:52
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Construction of a Noncentrosymmetric Luminescent Coordination Polymer from [BaL <sub/>3</sub> ] Unit (L = Pyridine-2,6-dicarboxylate Acid) and Li(I) Ion
摘要： This work presents the synthesis, crystal structure and properties of a novel noncentrosymmetric (NCS) coordination polymer (CP), namely, (Me2NH2)3[BaLi(2,6-PyDC)3(H2O)] (1) (2,6-PyDC = pyridine-2,6-dicarboxylate acid), which represents the first example of BaLi-CPs with 2,6-PyDC ligand. Single-crystal X-ray structural analysis reveals that the compound features a two-dimensional (2D) layered structure. The simplified structure of each layer belongs to the hcb topology. The second harmonic generation (SHG) response of 1 is about 0.5 times that of KH2PO4 (KDP) marker. What is more, 1 emits bright blue light upon the excitation of 365 nm UV light with the quantum yield (QY, Φ) of 1.63%. The successful construction of this compound convinces the feasibility of constructing NCS CPs via the combination of [BaL3] unit and Li(I) ion.
关键词： noncentrosymmetric,heterometallic complex,luminescence,nonlinear optics
更新于2025-09-23 15:23:52
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On the Double Nano-Coned Graphite Metasurface-Based Multiband CIC Absorber
摘要： Spectral characteristics of nano-engineered absorber comprised of nano-cone-shaped multi-layered (or cascaded) graphene metasurface (that results in graphite medium) were investigated under different chemical potentials and incidence conditions. The configuration of the proposed absorber is of the conductor-insulator-conductor (CIC) kind, wherein the top and bottom metasurfaces are identical in a pattern having the array of graphite-cones. Such three-layer CIC absorber hosts relatively thick dielectric substrate sandwiched between graphite nano-cone-based metasurfaces, in order to trap incidence electromagnetic fields. The results in respect of absorbance revealed usefulness of the proposed structure in spectral filtering in the visible and far-infrared regimes. Also, the tuning feature of absorber through altering the chemical potential of metasurfaces was highlighted.
关键词： Nano-engineered mediums,Complex mediums,Metamaterial absorbers,Graphene structures
更新于2025-09-23 15:23:52