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摘要： Seven derivatives of 2-(4-aminophenyl)naphtho-1,4-quinone were prepared by oxidative coupling of secondary and tertiary anilines, or carbazole, with naphtho-1,4-quinone. The substituted quinone derivatives displayed photophysical properties that were dependent upon the nature of the substituents bonded to the amino group (secondary or tertiary, alkyl or aryl) and to an extent upon the rotational freedom of the substituted amino group. All compounds displayed a low energy intramolecular charge transfer (ICT) band in the visible region of the absorption spectrum and in a general manner a positive, although complex, solvatochromic behavior. The solvent effect was analyzed in terms of the solvent polarity scale E_T (30) and by multi-parametric analyses (Kamlet-Abboud-Taft and Catálan). The solvent polarizability (SP) was an important parameter for all dyes, whilst the hydrogen bond donor basicity (SB) was also important for secondary amino substituents. Binary solvent mixtures (hexane/EtOH) revealed a linear change in λ_max of the ICT band at low EtOH concentration (up to about 15% V/V depending upon the dye) and non-linear behavior at higher concentrations of EtOH. Additionally, compounds 1–4 displayed molecular switch acidochromic behavior in the presence of trifluoroacetic acid where the ICT band was extinguished but restored after addition of Et₃N. The corresponding pK_a values relative to TFA for the equilibrium dye/dye-H⁺ were determined by calculation of ΔpK_a. The use of triflic acid had a similar effect to that of TFA upon the absorption spectrum of 3, but for compound 6 a large bathochromic shift of the ICT band was observed. The use of TD-DFT calculations, with an implicit solvation model, gave results consistent with the photo-excitation experimental observations and provided further insight into the und

摘要： This paper presents an experimental study of self-broadening and self-shift coefficients for 115 water vapor absorption lines in the 3900–4310 cm^–1 spectral range. Ten high-resolution absorption spectra of H₂O were recorded at room temperature using a Bruker IFS 125 HR Fourier transform spectrometer at the V.E. Zuev Institute of Atmospheric Optics (Tomsk). A multispectrum fitting procedure, employing a quadratic speed-dependent Voigt (qSDV) line profile, was applied to retrieve line parameters: positions, intensities, broadening and shift coefficients, and speed-dependent terms. The retrieved parameters are compared with existing data from the HITRAN2024 database and previous studies. For the broadening coefficients, the best agreement is observed with the results of Loos et al.

关键词： Façade fires   Upward fire spread   Building integrated photovoltaic material   Building electrification  

摘要： This study examines the upward fire spread characteristics of photovoltaic (PV) façade claddings in comparison to conventional building materials, to improve the understanding of fire safety implications for Building-Integrated Photovoltaics (BIPV). Through mid-scale experimental testing, the upward fire spread over PV claddings was measured using Long-wave infrared (LWIR) thermography, effectively tracking pyrolysis fronts and thermal damage. Bifacial dual-glass (GG) modules demonstrated slower fire spread than monofacial glass-plastic (GP) modules due to enhanced material resilience and encapsulation. Cavity conditions also affected the upward fire spread rates, with open cavities promoting rapid flame propagation and closed or channelled cavities delaying cavity ignition until glass breakage occurred at temperatures between 400 and 550 °C. Energized modules exhibited increased fire spread rates, approximately 17% for GP and 40% for GG modules, highlighting the impact of PV operational temperatures. Fire spread rates varied widely, with GG modules ranging from 1.1 to 2.9 mm/s and GP modules accelerating from 0.8 to 0.9 mm/s to 28–47 mm/s under dual-sided heating. Notably, GP modules surpassed the fire spread rates of conventional materials such as plywood and PMMA under similar conditions.

关键词： 1,8-Naphthyridines   Imidazoles   Imidazo[1,2-a]naphthyridines   Mercury(II) sensor  

摘要： Two novel 2,8-phenyl(thienyl)-4-(trifluoromethyl)-imidazo[1,2-a][1,8]naphthyridines (6a and 6b) were synthesized in 30–40% yields. In these compounds, the 2,8-phenyl(thienyl) substituents are C₆H₅ and 2-thienyl, respectively. The target molecules were obtained via an intermolecular and regioselective [3 + 2] cyclocondensation reaction of a series of designed 7-aryl-2-amino-5-(trifluoromethyl)-[1,8]naphthyridines (3) with 1-aryl(thienyl)-2-bromoethanones (5). The amino naphthyridines 3 were prepared from the reaction of 2,6-diaminopyridine (2) with 4-aryl-4-methoxy-1,1,1-trifluorobut-3-en-2-ones (1). The α-brominated ethanones 5 were synthesized from acetophenone or methyl heteroaryl ketones (4) and elemental bromine. The new compounds 6a–b were fully characterized by ¹H and ¹³C NMR, FTIR spectroscopy, and HRMS. TGA experiments showed that compounds 6a–b exhibit good thermal stability, with decomposition in the 293–321 °C range. The optical and electrochemical properties of the derivatives 6 were determined by UV-Vis, steady-state and time-resolved fluorescence emission (in solution and in the solid state), TD-DFT calculations, and redox potential measurements. In addition, the compounds 6 show good performance for the detection of mercury(II) ions in solution and in real samples (cosmetics).

摘要： Imposing an electric field could intensify reactions under mild conditions. This study proposed to enhance alkane cracking for light olefins production, one typical process requiring harsh conditions, by electric field in the catalysis by Zr-doped CeO₂ (Ce_xZr_1−xO₂). It was found that Zr incorporation significantly enhanced oxygen storage/release capacity of CeO₂. Spectroscopic analysis revealed that electric field induced lattice distortion in the (2 0 0) plane, and the resulting elongated Ce-O bonds facilitated lattice oxygen release. Under the reaction conditions of electric power of 10 W with external heating at 400 °C, n-hexane conversion reached 59.3% and light olefins selectivity was 67.4% over Ce_0.50Zr_0.50O₂. These results markedly outperformed the values obtained in the conventional thermal mode (n-hexane conversion of 0.5% and light olefins selectivity of 13.1% at 450 °C). And it was found that the n-hexane conversion increased linearly with the increase of migrated lattice oxygen content in the catalyst. DFT calculations show that the electric field optimized the d-p orbital hybridization between Ce_0.50Zr_0.50O₂ and n-hexane, enhanced the adsorption of reactant on the catalyst, and accelerated the charge transfer between the catalyst and reactant. In situ synchrotron radiation vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) demonstrated that the electric field could accelerate n-hexane dehydrogenation to form more hexene and trigger the formation of free radicals (e.g., C₂H₅·) under 400 °C. All the above led to efficient n-hexane cracking to light olefins, especially ethylene, under an electric field at mild conditions. This work provides an alternative strategy for the low-carbon transformation of the petrochemical industry.

摘要： The reconstruction of the runaway electron (RE) energy distribution is critical for understanding RE dynamics and mitigation in tokamak plasmas. In this work, the energy distribution of runaway electrons in a low-density Ohmic discharge of the Thailand Tokamak-1 (TT-1) was determined by unfolding hard X-ray (HXR) spectra measured using a LaBr${}_3$(Ce) scintillation detector. To address the ill-posed inverse problem caused by the complex detector response, a comprehensive response function matrix was constructed using FLUKA Monte Carlo simulations, incorporating the detailed TT-1 geometry and the detector. Two statistical unfolding algorithms, the iterative Bayesian method and Maximum Likelihood Estimation (MLE), were applied to experimental data from a representative low-density discharge. The reconstructed spectra from both methods showed excellent agreement, with a relative difference on the order of $10^{-4}$ %. The results suggest the energy distribution of runaway electrons centered around 6.5 MeV. This study establishes a robust methodology for RE energy diagnostics in TT-1, providing a necessary framework for future transport and loss mechanism studies.

关键词： Morphing Wings   Spanwise Travelling Waves   Turbulence   Shear Layers   High-Fidelity numerical simulations   Aerodynamic Performance  

摘要： The effect of spanwise travelling wave (STW) morphing applied in the near trailing edge region of wings is investigated through High-Fidelity numerical simulations. This concept is part of the bioinspired electroactive morphing wings studies conducted in the context of the European research project HORIZON 2023–2027 PATHFINDER N°101129952 BEALIVE (“Bioinspired Electroactive Aeronautical multiscale LIVE-skin”). The numerical simulations were performed with the Navier-Stokes Multi Block (NSMB) solver, using the Arbitrary Lagrangian Eulerian (ALE) method to account for the moving and deforming grid. The Organised Eddy Simulation (OES) turbulence modelling was employed to capture the dynamics of coherent structures. The configuration studied corresponds to an A320 wing in the low subsonic regime, with a chord of $\mathit{70 cm}$, a span of $\mathit{60 cm}$, a Mach number of $\mathit{0.063}$, an incidence of

来源 ScienceDirectJournal 详细信息

摘要： Ba(Mg_1/3Ta_2/3)O₃ (BMT) is a promising microwave dielectric material for 5 G resonator applications owing to its exceptionally high Q×f value exceeding 300 THz. In this study, the temperature dependence of the dielectric loss (tan δ) previously reported for BMT, was reanalyzed using inelastic neutron scattering data, the temperature dependence of thermal conductivity, and microstructural observations of domain boundaries. The temperature dependence of tan δ was separated into a temperature‑proportional term and a Debye‑type relaxation term. The former analysis revealed that BMT possesses an exceptionally small third‑order lattice‑energy term. Electron‑density distributions derived from synchrotron radiation X-ray diffraction and maximum-entropy-method analysis indicate a highly localized electron distribution around Ta ions, which is inferred to suppress lattice anharmonicity and thereby reduce dielectric loss. The latter analysis showed that the Debye relaxation originates from structural motifs associated with domain boundaries. This interpretation is further supported by the absence of relaxation behavior in BMT ceramics sintered in a nitrogen atmosphere, in which domain boundaries are significantly reduced and relaxation behavior is absent. These results clarify the intrinsic mechanisms governing dielectric loss in BMT and provide guidance for further loss reduction through microstructural control.

关键词： WN   Phase composition   XPS   Peak fitting   Chemical bonding  

摘要： The reliability of XPS spectra interpretation of heterogeneous materials exhibiting compositionally-driven phase transformations is shown to improve by a comprehensive sample analysis including characterization of microstructure, elemental composition, impurity level, and phase constitution. This approach is demonstrated here for a series of W_1-xN_x films with N content varying in the range 0 ≤ x ≤ 0.65, which results in a complex evolution of W 4f spectra. The reliability of peak models is further enhanced by performing self-consistent XPS analysis from all major core level spectra (W 4f, N 1s, O 1s, and C 1s) in liaison with XRD (for crystalline phase content, lattice parameters, preferred orientation), ToF-ERDA (elemental composition, impurity levels), SEM and TEM (micro- and nano-structural analysis), and SAED (crystalline content down to the nm-level). It is thus found that a phase transformation occurs as x increases from bcc α-W(N) with x = 0.06 to bcc α-W(N) + cubic β-W_yN (0.08 ≲ x ≲ 0.27), cubic β-W_yN + hexagonal W₂N₃ (0.36 ≲ x ≲ 0.56), and finally to cubic β-W_yN + amorphous WN₂ (0.62 ≲ x ≲0.65). The comparison of spectra recorded before and after Ar⁺ etching reveals that sensitivity to sputter damage varies greatly between different phases. This integrated methodology is particularly valuable for transition metal nitrides, carbides, and related compounds exhibiting continuous structural evolution with overlapping XPS signatures.