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Liquid Crystals - Self-Organized Soft Functional Materials for Advanced Applications || Binary Mixture Composed of Nematic Liquid Crystal and Carbon Nanotubes: A Theoretical Description
摘要： Based on the phenomenological model first presented by van der Schoot et al., which predicts the alignment of carbon nanotube (CNT) dispersions in thermotropic nematic liquid crystals, we present the extensive results concerning the phase diagram and the orientational properties of the mixture in this chapter.
关键词： phase transition,liquid crystal,carbon nanotube
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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On-demand CO release for amplification of chemotherapy by MOF functionalized magnetic carbon nanoparticles with NIR irradiation
摘要： Carbon monoxide (CO) gas therapy combined with chemotherapy and photothermal therapy (PTT) is a promising treatment mode for malignant tumor. Herein, we firstly reported doxorubicin (DOX) loaded Mn carbonyl modified Fe (III)-based nanoMOFs (MIL-100) coated PEGylated magnetic carbon nanoparticles (denoted as MCM@PEG-CO-DOX NPs) as theranostics nanoplatforms for near-infrared (NIR)-responded CO-DOX combination therapy. MIL-100 as a good nanocarrier of DOX with high loading capacity can also chelate the Mn carbonyl after a smart modification. Meanwhile, magnetic carbon core possessed photothermal effect, which can convert the NIR light to heat by an 808 nm laser irradiation, resulting in the on-demand release of CO and DOX. As a result, combining with PTT, MCM@PEG-CO-DOX NPs killed tumor efficiently. Moreover, our synthesized MCM@PEG-CO-DOX NPs were capable of realizing tumor dual-mode imaging including magnetic resonance imaging (MRI) and photoacoustic imaging (PAI).
关键词： synergistic treatment,dual-mode imaging,MOFs,CO gas therapy,carbon nanoparticles
更新于2025-09-23 15:23:52
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Insight into the mechanisms for hexavalent chromium reduction and sulfisoxazole degradation catalyzed by graphitic carbon nitride: The Yin and Yang in the photo-assisted processes
摘要： As robust polymeric catalysts, graphitic carbon nitride (g-C3N4) has been known to have great application potential in environmental remediation. However, the mechanisms in the photo-assisted catalytic processes during the reduction or oxidation of pollutants are still difficult to discern and therefore not well studied. In this work, visible-assisted catalytic reduction of hexavalent chromium (Cr(VI)) or oxidation of sulfisoxazole (SIZ) by g-C3N4 with the addition of formic acid (FA) or potassium peroxydisulfate (PS) were systematically investigated. Effects of operation parameters such as g-C3N4 dosage, FA concentration, Cr(VI) concentration, solution pH, PS concentration were studied. The results showed g-C3N4 can be effective and robust catalyst for both the reduction (Yin) and oxidation (Yang) reactions in the environmental remediation. Mechanisms were studied by using electron spin resonance (ESR) spectroscopy. The results revealed the CO2?? is the predominant radical for Cr(VI) reduction in the g-C3N4/FA/Vis system and the SO4?? and ?OH are all the main radicals for the oxidation of SIZ in the g-C3N4/PS/Vis system. The photo-generated carriers by g-C3N4, act as radical initiator, were responsible for the production of the reactive radical species in aqueous solution. This work not only shed a new light on the application of semiconductor polymers for the removal of micropollutants and also will expand the applicability of the polymeric photocatalysts for environmental remediation.
关键词： Micropollutants,Sulfisoxazole,Hexavalent chromium,Mechanisms,Graphitic carbon nitride
更新于2025-09-23 15:23:52
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Ethanothermal synthesis of phenol-derived carbon dots with multiple color emission via a versatile oxidation strategy
摘要： Herein, we report an ethanothermal synthesis of multicolor fluorescent carbon dots (CDs) by using a series of phenols and oxidants as the precursors. The emission colors of CDs are well-controlled at blue, green, yellow or red wavelengths by adjusting the combination of a phenol and an oxidant. And the naphthalenediol with highly reactivity and the oxidant with heavy halogen atom result in CDs exhibiting long wavelength emission. The resulting nanodots are characterized as amorphous aggregates with abundant oxygen species. The phenol-derived CDs can be used as highly processible fillers to fabricate epoxy composites, and a white light-emitting diode (LED) employing the multicolor CDs/epoxy composite as the light converter is also demonstrated.
关键词： Carbon dots,Photoluminescence,Phenols
更新于2025-09-23 15:23:52
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Low-cost effective photocatalytic activity under visible light of pitch-based porous carbon nanofiber composites aided by zinc oxide
摘要： To explore and develop an economical, novel, and effective photocatalyst for the degradation of methylene blue (MB) under visible-light irradiation, polyacrylonitrile (PAN)/pitch-based carbon nanofibers (CNFs) with ZnO (PPZn) are successfully produced by one-step electrospinning of PAN, pitch, and zinc acetate in dimethylformamide (DMF) solution. The charge separation rate, adsorption capacity, and visible-light harvesting effects are all enhanced by the synergistic effect of PAN/pitch-based CNFs and ZnO coupling. The resulting PPZn photocatalysts exhibit excellent removal capacity of 100% of MB within 30 min and a kinetic rate constant of 0.018 min?1 under visible light. PPZn also exhibits a consistent and stable photocatalytic performance by maintaining nearly 100% removal of 15 ppm MB over 8 regeneration cycles. The PP-based CNFs in PPZn act as a charge reservoir to afford fast transport for suppressing the e?–h? recombination and high electrical conductivity induced by the pitch, thereby expanding the visible-light response. The PP(3)Zn composites demonstrate a promising potential as a low-cost photocatalyst material offering excellent photocatalytic efficiency in the visible-light spectrum.
关键词： Carbon nanofiber,ZnO,Methylene blue,Pitch,Visible light,Photocatalytic activity
更新于2025-09-23 15:23:52
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Photoluminescence carbon dot as a sensor for detecting of Pseudomonas aeruginosa bacteria: Hydrothermal synthesis of magnetic hollow NiFe2O4-carbon dots nanocomposite material
摘要： The purpose of this research is synthesis of photoluminescence nanoparticles for detection of Pseudomonas aeruginosa that is feasible for bio medial applications. Carbon nano-templates were prepared from soot by burning of almond as a green precursor. Then NiFe2O4 nanoparticles were synthesized on the carbon templates. For preparation of hollow structures, the product was calcinated for removing of carbon templates. Finally, carbon dots were synthesized on the hollow nickel ferrite cores by applying ethylene diamine and citric acid. Phase of the products was approved by X-ray diffraction (XRD), scanning electron microscopy (SEM) depict the morphology and transmission electron microscopy (TEM) probe the grain size and hollow structures of the nickel ferrite, carbon dot and nanocomposites. Fourier transform infrared (FT-IR) spectroscopy approved the purity of the nanostructures. Ultraviolet-visible (UV-Vis) absorption and photo-luminescence (PL) spectroscopy confirmed appropriate photo-luminescence under ultraviolet irradiation. Vibrating sample magnetometer (VSM) shows ferromagnetic property of the both hollow NiFe2O4 and nickel ferrite-carbon nanocomposite. This work presents a new nanostructure as green prepared photoluminescence sensor for detecting of Pseudomonas aeruginosa bacteria, lead and mercury ions. Outcomes confirm decreasing in photoluminescence intensity of the nanocomposite by enhancing of Pseudomonas aeruginosa, Pb(II) and Hg(II) ions. Antibacterial effect of NiFe2O4-carbon dot on the degradation of Pseudomonas aeruginosa bacteria was also examined.
关键词： Nanostructures,Carbon Dots,Magnetic,Photoluminescence,P. Aeruginosa Bacteria
更新于2025-09-23 15:23:52
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Mass Production of High-Purity Semiconducting Carbon Nanotubes by Hydrochloric Acid-assisted Gel Chromatography
摘要： Mass production of high-purity semiconducting single-wall carbon nanotubes (s-SWCNTs) is critical for their application in the electronic and optoelectronic devices. Here we reported a method for the high-efficiency separation of high-purity s-SWCNTs with the acid-assisted gel chromatography, in which hydrochloric acid (HCl) was used to selectively oxidize metallic SWCNTs (m-SWCNTs) and enhance the difference in the interaction of metallic and semiconducting nanotubes with gel. Specifically, the concentration of HCl in the eluent was gradually increased to elute the carbon nanotubes adsorbed in the gel column step by step. The m-SWCNTs were firstly eluted at a low HCl concentration, and high-purity s-SWCNTs were selectively eluted at a higher HCl concentration. The final residues containing a relatively high content of m-SWCNTs and amorphous carbon impurities were left in the gel columns. Optical and electrical characterizations confirmed that the purity of the s-SWCNTs extracted from various raw SWCNT materials, especially CoMoCAT (7, 6), was improved greatly. Moreover, multiple single-chirality SWCNTs were firstly separated from the purified semiconducting CoMoCAT (7, 6) nanotubes. Our present work provides a simple and controllable way for the mass separation of high-purity s-SWCNTs and single-chirality species, which would accelerate their application in the field of electronics, optoelectronics and bio-imaging.
关键词： hydrochloric acid,separation,gel chromatography,Semiconducting carbon nanotubes,single-chirality
更新于2025-09-23 15:23:52
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Low-power-consumption Fiber-optic Anemometer based on Long-period Grating with SWCNT Coating
摘要： We report a low-power-consumption fiber-optic 'hot wire' anemometer (HWA) based on long-period grating (LPG) with single-wall carbon nanotubes (SWCNTs) coating. A uniform SWCNT film is deposited on a bare LPG acting as both light coupling and sensing element. By carefully selecting the order of the cladding mode and operating wavelength, the LPG shows a much higher temperature sensitivity than that of a regular fiber Bragg grating (FBG). Besides, SWCNT is a single-wall cylindrical nanostructure material with excellent absorption in the infrared range and high thermal conductivity. Due to these two features, the proposed sensor has extremely low power consumption and simple operation by utilizing a broadband light source (BBS) as both heating source and probing light source. A sensitivity of 102.5 pm/(m/s) at the wind speed of 1 m/s was obtained experimentally with 1.6-μm-thick SWCNT film.
关键词： Temperature.,Fiber-optic anemometer,long-period fiber grating,Carbon nanotube
更新于2025-09-23 15:23:52
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Fracture behavior of carbon fiber reinforced polymer composites: An optical study of loading rate effects
摘要： Crack initiation and growth in single-edge notched unidirectional T800s/3900-2 CFRP laminates are studied under stress wave and quasi-static loading conditions. An optical technique called reflection-mode Digital Gradient Sensing is also extended to study fracture mechanics of CFRP by using it in conjunction with ultrahigh-speed photography to perform full-field measurement of crack-tip deformations in the pre- and post-crack initiation regimes. DGS is capable of measuring two orthogonal surface slopes in the crack-tip vicinity as angular deflection of light rays. A method for extracting crack-tip parameters - the instantaneous crack speed and stress intensity factor (SIFs) histories - associated with the stationary and propagating cracks using measured surface slopes is presented. The effect of fiber orientation in the range 0°-60° relative to the initial notch and two loading rates are investigated. Nominally mode-I fracture occurs when the fiber orientation is 0° whereas mixed-mode fractures ensue in others. Besides crack initiation occurrence at higher loads as fiber orientation increases, the SIF histories imply strong fiber bridging at low fiber orientations under quasi-static conditions. Furthermore, this CFRP shows significant loading rate dependence during crack growth. Unlike stress wave loading conditions, an increasing crack growth resistance immediately after crack initiation is seen under quasi-static conditions.
关键词： Carbon fiber reinforced plastics,Loading rate effects,Crack growth behavior,Dynamic fracture,Digital Gradient Sensing
更新于2025-09-23 15:23:52