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oe1(光电查) - 科学论文

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出版时间
  • 2019
研究主题
  • fan-in/out devices
  • polymer optical waveguide
  • the Mosquito method
  • space division multiplexing
应用领域
  • Optoelectronic Information Science and Engineering
机构单位
  • Keio University
830 条数据
?? 中文（中国） ▾

  • Assembly of shell/core CDs@CaF2 nanocomposites to endow polymer with multifunctional properties

    摘要： Assembly of shell/core CDs@CaF2 nanocomposites to endow polymer with multifunctional properties. The shell/core structure of CDs@CaF2 nanocomposites (CCNCs) were prepared by assembling fluorescent carbon dots (CDs) inside the inorganic CaF2 substrates using co-precipitation interaction. CDs endow the CaF2 with the properties of good UV-absorbing behavior and efficient blue light emission instead of rare earth such as Eu that is expensive and susceptible to polluting environment during the mining process. Due to nanometer size and surface effect of nano CaF2, and approximate refractive index between CaF2 and polyethylene (PE), CCNCs/PE film exhibits better elongation at break than pure PE film while maintaining high transparency and visible light transmittance. Simultaneously, the CCNCs/PE film was experimentally demonstrated to have outstanding performance of anti-UV and blue light conversion, which decide that CCNCs can be a novel and promising multifunctional additive applied in polymers especially for greenhouse film.

    关键词： CaF2,Carbon dots,Polymer,Light conversion,Anti-UV,Nano-toughening

    更新于2025-09-23 15:23:52

  • Controlling Chain Coupling and Single Chain Ligation by Two Colours of Visible Light

    摘要： While photochemical synthesis offers access to spatiotemporal reaction control, its potential to selectively address specific reactions by the colour of light is usually limited by ubiquitous spectral absorption overlaps of the reactive groups. Inhere, a new concept is introduced that actively suppresses one ligation reaction by triggering the cycloreversion of the [2+2] cycloaddition of styrylpyrene. Combination of the photoreversible styrylpyrene chemistry with the [4+4] cycloaddition of 9-triazolylanthracene allows to initially induce chain coupling using UV light and to subsequently ligate the formed single chain nanoparticle (SCNP) with a second polymer chain using blue light. Seizing upon the first sequence independent λ-orthogonal reactivity established in here, the same macromolecular architecture was obtained in reverse irradiation sequence, by blue and subsequent violet light irradiation – completely foregoing high energy UV-light.

    关键词： Polymer Ligation,Orthogonal Reactions,RAFT polymerization,Photochemistry,Single Chain Nanoparticles

    更新于2025-09-23 15:23:52

  • Comprehensive investigation of surface quality and mechanical properties in CO2 laser drilling of GFRP composites

    摘要： The present paper aims to study different laser drilling/cutting parameters including laser intensity, cutting speed, and gas pressure in order to achieve minimum surface roughness (Ra), heat-affected zone (HAZ), taper angle (TA), and maximum tensile strength (TS) of the laser-drilled glass fiber-reinforced plastic (GFRP) laminate. Full factorial design of experiment method and analysis of variance were adopted to investigate the effect of each parameter on the responses, and in addition, the surface roughness and tensile strength were compared with that of conventional drilling. The morphology of the laser-drilled holes was studied through the scanning electron microscopy (SEM). It was found that optimum laser drilling parameters can yield higher tensile strength and lower surface roughness in drilled GFRP laminate compared to the conventional drilling. Moreover, multi-response optimization was carried out on the results in order to obtain maximum tensile strength, minimum HAZ, minimum surface roughness, and minimum taper angle. The results revealed that the laser intensity, cutting speed, and assist gas pressure should be set at 2.04 W/cm2, 8 mm/s, and 4 bar, respectively, to obtain higher tensile strength and surface integrity. The results drawn from this study can be applied to improve the surface quality and mechanical properties of laser drilling of FRP materials especially in aircraft part manufacturing.

    关键词： FRP,HAZ,Laser machining,Mechanical properties,Fiber-reinforced polymer composite

    更新于2025-09-23 15:23:52

  • [IEEE 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Vladivostok, Russia (2018.10.3-2018.10.4)] 2018 International Multi-Conference on Industrial Engineering and Modern Technologies (FarEastCon) - Experimental Study of the Stress-Strain State Features of Outlet Guide Vane Made From Polymer Composite Material Using Fiber Optic Sensors

    摘要： An estimation technique for the stress-strain state of the outlet guide vane design of an aircraft propulsion system made of polymer composite materials (PCM) using fiber-optic sensors is proposed. Fiber-optic sensors allow creating details with the possibility of self-diagnosis and forecasting the resource of work. This issue is particularly relevant when using PCM in highly loaded aircraft engine elements. The object of the study is the outlet guide vane (OGV) made of an equally strong carbon cloth on an epoxy binder. The tests were carried out on a universal servo-hydraulic machine. The data from fiber-optic sensors was carried out using an interrogator ASTRO X327. The comparison of the experiment and the numerical calculation were performed using the software package ANSYS.

    关键词： polymer composite material,fiber optic sensors,numerical calculations,stress-strain state

    更新于2025-09-23 15:23:52

  • Side chain dynamics in semiconducting polymer MEH‐PPV

    摘要： The characteristic nanoscale dynamics of the alkyl side groups in the light-emitting polymer poly[2-methoxy-5-(20-ethyl-hexyloxy)-1,4-phenylene vinylene] have been investigated using quasi-elastic neutron scattering (QENS). The measurements were taken below the polymer’s glass transition (T ≤ Tg ’ 353 K), where the main backbone is in a rigid state and does not contribute to the broadening of the QENS signal. An analytical diffusion model consisting of a static term and two dynamical components, characterizing the flexible side groups, provide an excellent fit to the experimental data. The two observed dynamical processes are all localized in character, with no meaningful dependence on temperature. The faster process, with characteristic timescale of (cid:2)18 ps at room temperature (RT), can be linked to the average mobility of the terminal protons of the alkyl chain, while the slower process, with characteristic timescale of (cid:2)170 ps at RT, to those protons at the other end of the alkyl chain, closest to the backbone. While the fraction of mobile protons contributing to the QENS signal increases with increasing temperature, the characteristic timescale and confining volume within which the protons are able to move locally depend chiefly on the polymer conformational state. ? 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47394.

    关键词： quasi-elastic neutron scattering,semi-conducting polymer,optical and photovoltaic applications,polymer dynamics,spectroscopy

    更新于2025-09-23 15:22:29

  • Fluorinated and Bio-Based Polyamides with High Transparencies and Low Yellowness Index

    摘要： Bio-based polyamides with high transparency and low yellowness were synthesized using 4,4'-bis(trifluoroacetamido)-α-truxillic acid (ATA-F1) and 4,4'-bis(pentafluoropropionamido)-α-truxillic acid (ATA-F2) as a fluoroalkylated aromatic dicarboxylic acid, and various aromatic diamines. The introduction of fluorine side chains improved the transparency of the polyamide film, and suppressed its yellowness. On the other hand, water repellency, which should be a general characteristic of the fluorinated polymers, was not observed. By using ATA-F1 and various aromatic diamines, aromatic and fluorinated polyamides were obtained. In addition, these also demonstrated a high transparency and a low yellowness index. The heat resistance properties of all the obtained polyamides was over 250 °C, and the characteristics of the bio-based polyamides from 4-aminocinnamic acid derivatives were retained.

    关键词： bio-based polymer,polyamides,transparent materials,fluorinated polymer

    更新于2025-09-23 15:22:29

  • Preparation and Characterization of Polymer Composite Materials Based on PLA/TiO2 for Antibacterial Packaging

    摘要： Polymer composite materials based on polylactic acid (PLA) filled with titanium dioxide (TiO2) nanoparticles were prepared. The aim of this work was to investigate the antibacterial action of TiO2 against a strain of E. coli (DH5α) to obtain information on their potential uses in food and agro-alimentary industry. PLA/TiO2 systems were prepared by a two-step process: Solvent casting followed by a hot-pressing step. Characterization was done as a function of particle size (21 nm and <100 nm) and particle content (0%, 1%, 5%, 10%, and 20%, wt %). Structural characterization carried out by X-ray diffraction (XRD) and Fourier Transformed Infrared spectroscopy (FTIR) did not reveal significant changes in polymer structure due to the presence of TiO2 nanoparticles. Thermal characterization indicated that thermal transitions, measured by differential scanning calorimetry (DSC), did not vary, irrespective of size or content, whereas thermogravimetric analysis (TGA) revealed a slight increase in the temperature of degradation with particle content. Bacterial growth and biofilm formation on the surface of the composites against DH5α Escherichia coli was studied. Results suggested that the presence of TiO2 nanoparticles decreases the amount of extracellular polymeric substance (EPS) and limits bacterial growth. The inhibition distances estimated with the Kirby-Bauer were doubled when 1% TiO2 nanoparticles were introduced in PLA, though no significant differences were obtained for higher contents in TiO2 NPs.

    关键词： antibacterial packaging,polylactic acid (PLA),polymer nanocomposites,TiO2 nanoparticles

    更新于2025-09-23 15:22:29

  • Tailorable and Flexible Conducting Films via Interfacial Modification of Polymer Fibers

    摘要： Portable devices have become lightweight, flexible, and even stretchable such that skin-like electronics are widely applicable, including in biomedical devices, soft robotics, and human/machine interfaces. Rendering these devices soft and flexible is highly desirable, as this would enable them to interact seamlessly with human skin and improve their wearing comfort. We demonstrate a convenient but effective method to fabricate flexible conducting films. These films consist of electrospun polyurethane (PU) fibers as the flexible substrate onto which copper was deposited. These Cu-PU films have excellent conductivity, and their resistance only increases slightly after extensive folding, even when folded into a paper crane with a resistance of 1.8 Ω. Furthermore, Cu-PU films can sense tension strength and exhibit stable Joule electrothermal performance. The Cu-PU-based heating glove could be heated to 40 °C in 30 s by applying 2 V. The simple but effective procedure presented here is suitable to fabricate flexible conducting film and may also promote the development of portable and flexible electronic products.

    关键词： flexible,polymer fiber,strain sensor,conductive,interfacial modification

    更新于2025-09-23 15:22:29

  • Sharp phase-separated interface of 6,13-bis(triisopropylsilylethynyl) pentacene/polystyrene blend films prepared by electrostatic spray deposition

    摘要： In this study, organic field-effect transistors (OFETs) based on blend films comprising 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) and polystyrene (PS) were fabricated. The blend films were prepared by electrostatic spray deposition (ESD). A vertically phase-separated structure (TIPS pentacene (top)/PS (bottom)) can be spontaneously formed without additional treatments such as solvent-vapor annealing, which is significantly different from the blend with poly(methyl methacrylate) (PMMA). Due to the sharp phase-separated interface, OFETs based on the TIPS pentacene/PS blend films exhibited superior characteristics and operational stability.

    关键词： Organic field-effect transistor,Small molecule/polymer blend,Electrostatic spray deposition,Vertical phase separation

    更新于2025-09-23 15:22:29

  • [IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Influence of Composition and Preparation on Crystalline Phases and Morphology in Poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) Relaxor-Ferroelectric Terpolymer

    摘要： The influence of chemical composition and crystallisation conditions on the ferroelectric and paraelectric phases and the resulting morphology in Poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE)) terpolymer films with 55.4/37.2/7.3 mol% or with 62.2/29.4/8.4 mol% of VDF/TrFE/CFE was studied. Poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) with 75/25 mol% VDF/TrFE was employed as reference material. Fourier-Transform Infrared Spectroscopy (FTIR) was used to determine the fractions of the relevant terpolymer phases, and X-Ray Diffraction (XRD) was employed to assess the crystalline morphology. The FTIR results show an increase of the fraction of paraelectric phases after annealing. On the other hand, XRD results indicate a more stable paraelectric phase in the terpolymer with higher CFE content.

    关键词： P(VDF-TrFE-CFE) terpolymer,Curie transition,relaxor-ferroelectric polymer,ferroelectric and paraelectric phases

    更新于2025-09-23 15:22:29