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Facile Synthesis of Luffa Sponge Activated Carbon Fiber Based Carbon Quantum Dots with Green Fluorescence and Their Application in Cr(VI) Determination
摘要： Carbon quantum dots (CQDs) were prepared by a chemical oxidation method using lu?a sponge based activated carbon ?ber as the raw material. The obtained CQDs were well characterized. The ?uorescence quenching e?ect of Cr(VI) ion on CQDs was investigated. The results show that the addition of Cr(VI) changes the intensity of the ultraviolet characteristic absorption peak of CQDs, and causes static quenching of the ?uorescence of CQDs. With the increase in the Cr(VI) concentration, the ?uorescence of CQDs was gradually extinguished linearly.
关键词： Activated carbon ?ber,Lu?a sponge,Cr(VI) determination,Fluorescence quenching,Carbon quantum dots
更新于2025-11-21 11:01:37
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Broad-band emission and color tuning of Eu3+-doped LiCa2SrMgV3O12 phosphors for warm white light-emitting diodes
摘要： In this study, series of Eu3+-doped LiCa2SrMgV3O12 (LCSMV) phosphors with broad-band emission and color tunable feature were prepared via solid phase reaction. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results presented a pure cubic phase product with micron-sized and homogeneous distribution of element. Their spectroscopic properties were investigated systematically by photoluminescence excitation (PLE) and emission (PL) spectra, temperature-dependent PL spectra and luminescence decay curves. The LCSMV phosphors displayed a strong absorption to ultraviolet light and a broad cyan emission. Moreover, in Eu3+-doped LCSMV phosphors, Eu3+ ion characteristic emissions at 589, 610, 651 and 705 nm, attributing to the 5D0→7F1, 7F2, 7F3 and 7F4 transitions, were observed. Along with Eu3+ ion concentrations increasing, the emission colors could be readily tuned from cyan to orange and the decay lifetimes of (VO4)3- became shorter. Meanwhile, electric dipole-dipole interaction was responsible to energy migration from (VO4)3- groups to Eu3+ ions. Further, the quantum efficiency (QE) values were estimated to be 32.5% for LCSMV host and 39.3% for LCSMV: 0.01Eu3+ sample. Finally, a LED lamp was prepared by integrating the blend of the LCSMV: 0.01Eu3+ phosphors and commercial blue-emitting BaMgAl10O17:Eu2+ phosphors with NUV chip (365 nm) and exhibited warm white light (CCT = 3655 K, Ra = 90), which may be applied in lighting and display field.
关键词： Self-activated luminescence,Color tunable,Light-emitting diode,Vanadate phosphor,Color rendering index,Broad-band emission
更新于2025-11-20 15:33:11
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Synthesis, energy transfer and multicolor luminescent property of Eu3+-doped LiCa2Mg2V3O12 phosphors for warm white light-emitting diodes
摘要： In this study, Eu3+-doped LiCa2Mg2V3O12 (LCMVO) phosphors with multicolor luminescent property were prepared by the solid phase reaction. Their structure, morphology and luminescent property were studied systematically by X-ray diffraction, scanning electron microscope and photoluminescence spectra. The LCMVO phosphors showed pure cubic crystal structure with space group (3Ia d ) and irregular spherical morphology. The excitation spectra showed a strong absorption to ultraviolet light. Under the excitation wavelength at 360 nm, they exhibited a cyan emission with a luminescence center at 520 nm. When Eu3+ ions were doped into LCMVO system, the Eu3+ characteristic emissions were also observed and the emission colors were tuned from cyan to orange via adjusting Eu3+ ion concentration. Further, electric dipole-quadrupole interaction and luminescence decay curves were adopted to explain the energy transfer from (VO4)3- to Eu3+. The emission spectra of as-obtained phosphors at different temperature were measured to evaluate their thermal stability. The quantum efficiency values were measured to be 42.5% for LCMVO host and 38.6% for LCMVO: 0.01Eu3+ sample. The final prepared LED lamp showed easeful warm white light with suitable Ra of 89 and CCT of 3847 K, respectively. These results suggest LCMVO phosphors may be applied in near ultraviolet chip-excited white light-emitting diodes.
关键词： energy transfer,multicolor luminescent,self-activated luminescence,excitation and emission spectra,vanadate phosphor,UV-LED
更新于2025-11-20 15:33:11
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Effective synthesis of nanoscale anatase TiO <sub/>2</sub> single crystals using activated carbon template to enhance the photodegradation of crystal violet
摘要： Nanoscale anatase TiO2 single crystals were successfully synthesized using three kinds of activated carbon (AC) templates through a simple sol–gel method. The optimal photocatalyst (T‐WOAC) was obtained using wood‐based AC template. X‐ray diffraction, transmission electron microscopy and Brunauer–Emmett–Teller analyses revealed that T‐WOAC possessed a small crystallite size of 8.7 nm and a clear mesoporous structure. The photocatalytic properties of samples were then evaluated through photodegradation of crystal violet (CV). Results implied that the photocatalysts prepared using the AC templates exhibited superior photocatalytic activity to that of the original TiO2. This enhancement may be due to the small crystallite size, large specific surface area and pore volume of the catalysts prepared with ACs. T‐WOAC showed high photocatalytic activity, CV degradation of 99.01% after 120 min of irradiation and k = 0.03914 min?1, which is 3.9 times higher than that of the original TiO2 (k = 0.00994 min?1). This result can be mainly attributed to the application of WOAC with moderate specific surface area and pore volume to produce T‐WOAC. Alkaline conditions benefitted the photodegradation of CV over photocatalysts. This work proposes a possible degradation mechanism of CV and indicates that the fabricated photocatalysts can be used to effectively remove CV from aqueous solutions.
关键词： photocatalyst,anatase TiO2 single crystals,sol–gel,crystal violet,activated carbon
更新于2025-11-14 17:04:02
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Facile color tuning of thermally activated delayed fluorescence by substituted ortho-carbazole-appended triarylboron emitters
摘要： We report the facile tuning of the emission color of thermally-activated delayed fluorescent (TADF) emitters based on an ortho-carbazole-appended triarylboron. A series of ortho-carbazole-appended triarylboron compounds (2-7) are prepared by introducing various electron-accepting substituents, such as phenyl, pyridyl, pyrimidyl, diphenylphosphine oxide, cyano, and dimesitylboryl groups, to the phenylene ring of the dimesitylphenylboryl (PhBMes2) acceptor moiety in the parent ortho-carbazole-appended triarylboron (CzoB, 1). The X-ray crystal structure of the cyano-substituted compound 6 confirms the twisted connectivity between the Cz and phenylene rings. All the compounds exhibit strong TADF (ΦPL = 48-93% in toluene) with large delayed portions. In particular, the emission bands gradually undergo bathochromic shifts from blue (l PL = 463 nm for 1) to greenish yellow (l PL = 532 nm for 7) depending on the electron-accepting substituents. Electrochemical studies show that the greater stabilization of the LUMO level compared to the HOMO is responsible for the red shifts of the emission. Theoretical studies further support the observed bathochromic shifts in the emission, as well as the small energy splittings (D EST) between the excited singlet and triplet states that afford the efficient TADF.
关键词： Ortho donor-acceptor,Color tuning,Triarylboron,Thermally activated delayed fluorescence
更新于2025-11-14 15:28:36
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Enhancing Reverse Intersystem Crossing via Secondary Acceptors: towards Sky-Blue Fluorescent Diodes with Tenfold-Improved Exter-nal Quantum Efficiency
摘要： How to simply but effectively facilitate reverse intersystem crossing (RISC) transition is always the key issue for developing high-performance thermally activated delayed fluorescence (TADF) dyes. In this work, as a proof of concept, a feasible strategy named 'acceptor enhancement' is demonstrated with a series of ternary blue emitters (xCzmPOnTPTZ) using diphenylphosphine oxide (PO) as secondary acceptors. Compared with its PO-free binary analogue, such simple introduction of PO groups in pCzPO2TPTZ dramatically enhances its RISC rate constant (kRISC) by 10 times to the level of ~105 s-1, accompanied by RISC efficiency (ηRISC) of 92%, which further improves the triplet-to-singlet upconversion for effective triplet harvesting in its devices. As the result, on the basis of a trilayer device structure, pCzPO2TPTZ realized a state-of-the-art external quantum efficiency (EQE) beyond 20% with tenfold improvement.
关键词： Organic Light-Emitting Diode,Thermally Activated Delayed Fluorescence,Excited State Transition,Blue Emission,Reverse Intersystem Crossing,Phosphine Oxide Acceptor
更新于2025-09-23 15:23:52
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Photocatalytic Degradation of Methylene Blue and Phenol Using TiO2/Activated-Carbon Composite Catalysts
摘要： Photocatalytic degradation of methylene blue and phenol were conducted separately in aqueous solutions using titania-activated carbon composites. Activated carbon composites of different textural features and light of different wavelength or energy were used in order explore their effects on the performance of titania-activated carbon catalysts. The catalysts (TiAC1, TiAC2 and TiAC3) were prepared by impregnating activated carbon supports with an aqueous suspension of titanium precursor (TiO2). The catalysts were characterized using BET, XRD and FTIR. The diffraction pattern showed strong peaks that are assigned to titanium anatase phase and weaker peaks that indicated low rutile phase. The FTIR showed broad peaks of Ti-O-Ti linkages in TiO2 particles. The photocatalytic degradation of methylene blue and phenol was performed separately in visible light and UV irradiation of different wavelengths. Adsorption was dominant in the case of methylene blue removal while photodecomposition was more pronounced in the case of phenol removal.
关键词： Photocatalysis,Phenol,Methylene blue,Titania,Activated carbon,Precursors
更新于2025-09-23 15:23:52
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Linear complex susceptibility of long-range interacting dipoles with thermal agitation and weak external ac fields
摘要： An analytical formula for the linear complex susceptibility of dipolar assemblies subjected to thermal agitation, long-range interactions, and an externally applied uniform sinusoidal field of weak amplitude is derived using the forced rotational diffusion equation of Cugliandolo et al. [Phys. Rev. E 91, 032139 (2015)] in the virial approximation. If the Kirkwood correlation factor of the dipolar assembly gK exceeds unity, a thermally activated process arising from the interaction-specific component arises, while for gK < 1 the susceptibility spectrum normalized by its static value is practically unaltered with respect to that of the ideal gas phase.
关键词： long-range interactions,thermally activated process,dipolar assemblies,thermal agitation,Kirkwood correlation factor,linear complex susceptibility
更新于2025-09-23 15:23:52
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Activated carbons with adsorbed cations as photocatalysts for pollutants degradation in aqueous medium
摘要： Oxidized activated carbon (AC) based on commercial coconut-shell carbon Aquacarb 607C has been prepared. This AC has micro-mesoporous structure and contains surface carboxyl and phenol/enol groups. Cu- and Co-containing ACs have been synthesized via ion-exchange in acid medium. According to potentiometric titration and XPS data, cation-exchanged forms of AC contain about 0.5% of metal ions. Such cation-containing ACs possess narrowed band gap compared oxidized AC as it is observed for doped oxides. Oxidized and cation-containing ACs have been tested as catalysts in photodegradation of dyes and phenol under UV- and visible irradiation. Initial oxidized AC is photoactive toward rhodamine B and methyl orange under UV illumination but inactive under visible light. For the first time it is shown that cation-exchanged forms of AC have enhanced activity towards rhodamine B, methyl orange and phenol in both UV and visible region. Therefore, the principal possibility of improving the photocatalytic properties of AC by introducing a minimal amount of copper and cobalt cations is shown.
关键词： Cation-exchanged forms,Decolourisation and mineralization,UV and visible irradiation,Activated carbon,Photocatalytic degradation
更新于2025-09-23 15:23:52
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Aberrant Activity of TAK1 is Associated with Retinal Pathology
摘要： Transforming growth factor-β-activated kinase-1 (TAK1) is a mitogen activated protein kinase kinase kinase that is involved in diverse biological roles across species. Functioning downstream of TGF-β, TAK1 mediates the activation of the c-Jun N-terminal kinase (JNK) signaling pathway, serves as the target of pro-inflammatory cytokines, such as TNF-α, mediates NF-κβ activation, and plays a role in Wnt signaling in mesenchymal stem cells. Still, the expression of TAK1 in the retina has not been defined. In our study, pathological and immunohistochemical assessments indicate a link between retinal pathology and TAK1 phosphorylation. We observed similar TAK1 expression both in non-obvious and obvious retinal pathologies. However, the phosphorylated form of TAK1 in the segments of retina with obvious pathology was hardly detected compared to its expression in the segments with non-obvious pathology. This finding indicates, for the first time, a possible involvement of TAK1 in human retinal pathologies. Better understanding the expression pattern of TAK1 may serve as a new therapeutic avenue for retinal pathologies.
关键词： Phosphorylation,Retinal pigment epithelium (RPE),Transforming growth factor-β-activated kinase 1 (TAK1)
更新于2025-09-23 15:23:52