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Surface Pretreatment of Fiber-Reinforced Plastics via VUV Radiation
摘要： Fiber-reinforced plastics (FRP) are of great importance for the transport sector, the aerospace industry, for wind power plants, in the building sector and in the field of sports and leisure applications. Optimization of the adhesive bonding process for FRP structures, especially the surface preparation prior to bonding, will be of a central importance in forthcoming expansion of FRP use. In this connection the key problem depends on the FRP polymer matrix. In the case of duroplastic matrix the main problem is the presence of release agent on the surface of joining components. For the thermoplastic matrix such as polypropylene (PP), the main problems are the low surface energy and the inertness of its surface. Conventional pretreatment methods, such as manual grinding, shall be replaced by energetic radiation technics like VUV lamps (vacuum ultraviolet spectral range: 100 – 200 nm). This approach is a non-contact method, characterized by high treatment homogeneity and material-saving properties, combined with no further fibers to be released. The surface of the thermoplastics is activated by the incorporation of oxygen, release agent contamination on the thermoset is cleaned or modified [1 - 8]. The results of the VUV surface activation of PP and CFRP with regard to the incorporation of functional groups, increase of surface energy, matrix degradation and the adhesion increase of adhesive bonds are presented. In addition, studies on the release agent coating and the release agent modification by VUV radiation are presented. The work is completed by considerations concerning possibilities to accelerate the process (in particular, wavelength dependence, influence of an inert gas or the moisture content). Finally, an evaluation of the VUV pretreatment is carried out on the basis of two specific applications.
关键词： VUV,irradiation,excimer,release agent,surface pretreatment,CFRP,FRP,GRP
更新于2025-09-23 15:22:29
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Exfoliation of graphite as flexible SERS substrate with high dye adsorption capacity for Rhodamine 6G
摘要： Adsorption is one of the most important processes in wastewater treatment, especially for dye removal. In addition to adsorption, there must be a vigilant technique, such as Surface Enhanced Raman spectroscopy (SERS), for detection of low concentration of dye molecules to detect water foiling. Herein, we report a simple, low cost, rapid and e?cient technique for the production of exfoliated graphite (EG) under microwave irradiation at 800 W in 1 min, as excellent adsorption material for Rhodamine 6G (R6G) dye. The e?ect of adsorption process parameters such as pH, contact time, isotherm models (Langmuir and Freundlich) and kinetic models (pseudo-?rst and pseudo-second-order) on dye removal under aqueous solutions, were investigated. The maximum adsorption capacity for R6G dye is 212.72 ( ± 5.3) mg/g. Meanwhile compressing of EG, into a ?exible graphite sheet (FGS) demonstrates responsive SERS for R6G molecules up to detection limit of 10?7 mol/L. However, with silver nanoparticle incorporation, the detection limit increases up to 10?12 mol/L. Performance of ?exible sheet checked over a month by rubbing sheet through paper and cloth doesn’t have any impact on the synthesis of exfoliated graphite. Aging factor of the sheet also shows reproducible SERS spectra after a month. These are the highest reported values till today, for adsorption of R6G dye on Exfoliated graphite, with reasonable SERS detection.
关键词： Microwave irradiation,Flexible graphite sheet,Exfoliated graphite,SERS,Adsorption
更新于2025-09-23 15:22:29
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Ultraviolet response of reduced graphene oxide/natural cellulose yarns with high flexibility
摘要： We prepared graphene yarn comprising reduced graphene oxide flakes and natural cellulose yarn by simple dip-coating and chemical reduction, and characterized its ultraviolet (UV) response under bending deformation. The as-prepared reduced graphene oxide cellulose yarns showed good basic properties including electrical conductivity (~1.0 S/cm) and mechanical stability (1,000 cycles), as well as a UV photoresponsivity of 1.31 mA/W (flat) and 1.0 mA/W (bent) and response times of 5 s/6 s (flat) and 6 s/7 s (bent). Our approach provides a path to realizing enhanced functional capabilities in natural cellulose textiles and their use in advanced smart textiles and wearable electronic/optoelectronic applications.
关键词： Flexibility,UV irradiation,Natural cellulose yarn,Reduced graphene oxide
更新于2025-09-23 15:22:29
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Prussian blue-encapsulated Fe3O4 nanoparticles for reusable photothermal sterilization of water
摘要： Waterborne health issues continue to grow despite the large number of available solutions. Current sterilization techniques to fight with waterborne diseases struggle to meet the demands on cost, efficiency and reach. Effective alternatives are pressingly required. Here we introduce Prussian blue coated ferroferric oxide (Fe3O4@PB) composites for water sterilization. The composites exhibit superior photothermal inactivation of bacteria under solar-light irradiation, with nearly complete inactivation of bacterial cells in only 15 min. Even for the mixed bacteria in authentic water matrices, the composites show excellent bacterial inactivation performance. Moreover, the highly magnetized iron core of the Fe3O4@PB enables magnetic separation and recycling. Multiple cycle runs reveal that Fe3O4@PB composites have exceptional stability and reusability. This work demonstrates a scalable, low-cost, high-efficiency and reusable sterilization method to improve water quality and safety.
关键词： Solar-light irradiation,Prussian blue,Recyclability,Water security,Photothermal sterilization
更新于2025-09-23 15:22:29
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CVD diamond film detectors for α particles with a new electrode structure of reduced graphene oxide/Au
摘要： (111)-oriented poly-crystalline diamond ?lms (PCDs) have been deposited on Si substrates by MPCVD technology. The new electrode structure of reduced graphene oxide (RGO)/Au was successfully fabricated onto PCDs. Using the circular transmission line model (CTLM), the contact resistance of 6.6 Ω cm?2 was obtained for RGO/Au electrode on PCD surface, which was notably lower than that of 97.4 Ω cm?2 for Ti/Pt/Au electrode. Furthermore, two detectors with these two type electrodes were made respectively. The dark current, photocurrent and energy resolution of these two detectors under 5.5 MeV α particles irradiation from a 241Am source were observed. The results demonstrated that the fabrication of RGO/Au electrode onto PCD can realize a ?ne ohmic contact. The photocurrent of 58.7 nA for the detector with RGO/Au electrode had higher values than that of 8.8 nA for the detector with Ti/Pt/Au electrode at the bias voltage of 100 V respectively. Due to the realization of good contact on PCD surface with RGO/Au electrode, the energy resolution of 11.9% for the detector with RGO/Au electrode better than that of 24% for the detector with Ti/Pt/Au electrode can be obtained. Fabrication of the RGO/Au electrode on PCD may provide a feasible way to improve its detection performance under α particles irradiation.
关键词： α particle irradiation,Diamond ?lm,Ohmic contact,RGO/Au electrode,Raman spectroscopy
更新于2025-09-23 15:22:29
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Single photon detection with SiPMs irradiated up to 1014?cm?2 1-MeV-equivalent neutron fluence
摘要： Silicon photomultipliers (SiPM) are solid state light detectors with sensitivity to single photons. Their use in high energy physics experiments, and in particular in ring imaging Cherenkov (RICH) detectors, is hindered by their poor tolerance to radiation. At room temperature the large increase in dark count rate makes single photon detection practically impossible already at 1011 cm?2 1-MeV-equivalent neutron fluence. The neutron fluences foreseen by many subdetectors to be operated at the high luminosity LHC range up to 1014 cm?2 1-MeV-equivalent. In this paper we present the effects of such high neutron fluences on Hamamatsu and SensL SiPMs of different cell size. The advantage of annealing at high temperature (up to 175?C) is discussed. We demonstrate that, after annealing, operation at the single photon level with a SiPM irradiated up to 1014 cm?2 1-MeV-equivalent neutron fluence is possible at cryogenic temperature (77 K) with a dark count rate below 1 kHz.
关键词： Cryogenic temperature,Radiation damage,Single photon detection,SiPM,Neutron irradiation,Annealing
更新于2025-09-23 15:22:29
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Perforating Freestanding Molybdenum Disulfide Monolayers with Highly Charged Ions
摘要： Porous single layer molybdenum disulfide (MoS2) is a promising material for applications such as DNA sequencing and water desalination. In this work, we introduce irradiation with highly charged ions (HCIs) as a new technique to fabricate well-defined pores in MoS2. Surprisingly, we find a linear increase of the pore creation efficiency over a broad range of potential energies. Comparison to atomistic simulations reveals the critical role of energy deposition from the ion to the material through electronic excitation in the defect creation process, and suggests an enrichment in molybdenum in the vicinity of the pore edges at least for ions with low potential energies. Analysis of the irradiated samples with atomic resolution scanning transmission electron microscopy reveals a clear dependence of the pore size on the potential energy of the projectiles, establishing irradiation with highly charged ions as an effective method to create pores with narrow size distributions and radii between ca. 0.3 and 3 nm.
关键词： 2D material,perforation,ion irradiation,MD simulation,molybdenum disulfide,highly charged ions,STEM
更新于2025-09-23 15:22:29
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Effects of flux pinning on the DC characteristics of meander-shaped superconducting quantum interference filters with flux concentrator
摘要： Superconducting quantum interference filters, or SQIFs, are a promising class of highly sensitive magnetometers benefiting from a highly peaked and symmetric magnetic response at zero-input flux. They can be used in magnetometry, e.g., in wideband applications. A simple solution to increase further their sensitivity is to add a superconducting flux concentrator (SFC) to their design. Using the ion irradiation process, we designed a meander-shaped SQIF enhanced with an SFC. The SFC improved the SQIF transfer factor by a factor of 8.4. However, high temperature superconducting (HTSc) devices are vulnerable to flux pinning, which can severely hinder their response. On the one hand, HTSc technologies alleviate the burden of cryogenics. On the other hand, applications that use SFCs in noisy and unshielded environments will become possible only if a better understanding of how this flux impacts the device's properties is achieved. We studied the relationship between the field present during the cooling process of the SQIF antenna (thereafter called 'cooling field') and the evolution of its DC response. We developed a simple and phenomenological model and were able to reproduce the degradation of the SQIF response. This work demonstrates the usability of SFC-enhanced SQIFs based on ion irradiated junctions in rather harsh conditions, in particular, an unshielded environment, and also gives an insight into the implications that such conditions cause on the application of SFCs in general.
关键词： ion irradiation,flux pinning,magnetometry,flux concentrator,superconducting quantum interference filters
更新于2025-09-23 15:22:29
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Study of Proton Irradiation Effects on p- and n-Type GaN Based-on Two-Terminal Resistance Dependence on 380keV Proton Fluence
摘要： 380 keV proton irradiation effects are investigated on p-GaN and n-GaN layers in GaN-based light emitting diode (LED) by characterizing current-voltage (I–V) characteristics of p-n junction, and two-terminal resistance of p- and n-GaN on both type of layers in LED wafer. Two-terminal resistance on n-GaN kept its initial value after the 1 × 10^14 cm^?2 fluence, and was remained the same order after the 1 × 10^15 cm^?2 fluence. On the other hand, p-GaN showed sensitive increase in two-terminal resistance after the 1 × 10^14 cm^?2, and six orders of increase after the 1 × 10^15 cm^?2 fluence. Observed sensitive increase of resistivity in p-GaN is explained as a lower initial hole density in p-GaN than the initial electron density in n-GaN layer.
关键词： proton irradiation effects,LED,GaN
更新于2025-09-23 15:22:29
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Photocatalytic Degradation of Estriol Using Iron-Doped TiO2 under High and Low UV Irradiation
摘要： Iron-doped TiO2 nanoparticles (Fe-TiO2) were synthesized and photocatalitically investigated under high and low ?uence values of UV radiation. The Fe-TiO2 physical characterization was performed using X-ray Powder Diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area analysis, Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Diffuse Re?ectance Spectroscopy (DRS), and X-ray Photoelectron Spectroscopy (XPS). The XPS evidenced that the ferric ion (Fe3+) was in the TiO2 lattice and unintentionally added co-dopants were also present because of the precursors of the synthetic method. The Fe3+ concentration played a key role in the photocatalytic generation of hydroxyl radicals (?OH) and estriol (E3) degradation. Fe-TiO2 accomplished E3 degradation, and it was found that the catalyst with 0.3 at.% content of Fe (0.3 Fe-TiO2) enhanced the photocatalytic activity under low UV irradiation compared with TiO2 without intentionally added Fe (zero-iron TiO2) and Aeroxide? TiO2 P25. Furthermore, the enhanced photocatalytic activity of 0.3 Fe-TiO2 under low UV irradiation may have applications when radiation intensity must be controlled, as in medical applications, or when strong UV absorbing species are present in water.
关键词： hydroxyl radical,estriol,iron-doped TiO2,photocatalytic activity,low UV irradiation
更新于2025-09-23 15:22:29