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Impact of corneal cross-linking combined with photorefractive keratectomy on blurring strength
摘要： The aim of this study was to evaluate the impact of corneal cross-linking combined with photorefractive keratectomy (PRK) on blurring strength. A total of 63 patients with keratoconus were recruited for this study, and two study groups were formed according to the therapeutic intervention: corneal collagen cross-linking (CxL) group (33 patients) received corneal cross-linking according to the Dresden protocol, while the rest additionally received topography-guided photorefractive keratectomy (tCxL). The impact of surgical procedure on blurring strength was assessed by power vector analysis. Potential association between blurring strength and vision-specific quality of life was assessed using the National Eye Institute Visual Function Questionnaire (NEI-VFQ) 25 instrument. Blurring strength presented excellent correlation with NEI-VFQ scores both preoperatively and postoperatively (all P,0.01). Both groups demonstrated nonsignificant changes in best-corrected visual acuity; however, only the tCxL group had significant reduction in blurring strength (13.48+10.86 [preoperative], 4.26+7.99 [postoperative], P=0.042). Only the combined treatment (tCxL) resulted in significant reduction in blurring strength. Moreover, the excellent correlation of blurring strength with NEI-VFQ scores indicates its reliability as an index of self-reported quality of life in keratoconus, since it seems to address the nonsignificant changes in best-corrected visual acuity following CxL treatments that are conceived as subjective improvement by the patient.
关键词： blurring strength,keratoconus,tCxL,cornea crosslinking
更新于2025-09-04 15:30:14
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Enhanced dielectric strength and energy storage density in BaTi0.7Zr0.3O3 ceramics via spark plasma sintering
摘要： Barium zirconate titanate (BaTi0.7Zr0.3O3) ceramics were prepared via spark plasma sintering (SPS) and conventional solid-state sintering (CS). Both samples exhibited single phase nature as confirmed from the X-ray diffraction analysis. Compared with CS sample, more homogeneous microstructure with smaller grain size was observed in the SPS sample, which greatly improved the dielectric strength of BaTi0.7Zr0.3O3 ceramics from 40 (CS) to 170 kV/cm (SPS). Although the polarization of SPS sample was lower than that of CS sample under the same applied electric field, the maximum energy storage density was improved to 0.51 J/cm3, which was about 4.5 times higher than that of the CS sample (0.12 J/cm3). Moreover, finite element simulation on the local dielectric field distribution was carried out, and the effects of microstructure on the dielectric strength were further confirmed.
关键词： BaTi0.7Zr0.3O3,energy storage density,spark plasma sintering,dielectric strength
更新于2025-09-04 15:30:14
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AIP Conference Proceedings [Author(s) 3RD INTERNATIONAL SCIENCES, TECHNOLOGY & ENGINEERING CONFERENCE (ISTEC) 2018 - MATERIAL CHEMISTRY - Penang, Malaysia (17–18 April 2018)] - Durability control of UV radiation in glass fiber reinforced polymer (GFRP) - A review
摘要： Glass Fiber Reinforced Polymer (GFRP) was commonly used as outer layer, and it may expose to the ultraviolet exposure and prone to UV radiation. UV radiation will lead to degradation of the GFRP itself and it will reduce the quality and function of GFRP. This paper is a review of past studies on UV Radiation of Glass Fiber Reinforced Polymer (GFRP) in transmission line tower. A study on UV radiation toward coupling steel laminates of GFRP pultruded show the load carry the capacity of the joint was found to be increase, it was due to polymerization of the adhesives. While, a study of UV radiation on GFRP show during the aging process GFRP show signs of plasticization and after 6 months the tensile strength of GFRP show substantial descending pattern and the tensile modulus were found less affected compared to tensile strength. Glass Fiber Reinforced Polymer (GFRP) has a good potential as a material to resist UV radiation.
关键词： tensile strength,tensile modulus,Ultra Violet radiation,GFRP
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - RSS-Based Direction-of-Arrival Estimation with Increased Accuracy for Arbitrary Elevation Angles Using ESPAR Antennas
摘要： In this paper, we have proposed an improved direction-of-arrival (DoA) estimation algorithm, which uses the power pattern cross-correlation (PPCC) estimator and received signal strength (RSS) values recorded at electronically steerable parasitic array radiator (ESPAR) antenna’s output port, providing more accurate DoA results for unknown signals impinging the antenna. The PPCC estimator in its original form provides accurate DoA estimation results for directions lying within the horizontal plane. However, the estimation accuracy drops for other elevation angles as the estimator relies on ESPAR antenna’s radiation patterns measurements in the horizontal plane only. Our proposed modification allows one to measure ESPAR antenna’s radiation patterns in two different elevation planes during the calibration phase, which improves PPCC-based DoA estimation algorithm’s overall accuracy for signals impinging the antenna from arbitrary elevation angles. The proposed algorithm has been verified during anechoic chamber measurements using our ESPAR antenna prototype.
关键词： electronically steerable parasitic array radiator (ESPAR) antenna,direction-of-arrival (DoA),received signal strength (RSS),Switched-beam antenna
更新于2025-09-04 15:30:14
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Effect of the anchoring strength on the phase behaviour of discotic liquid crystals under face-on confinement
摘要： In this study we have performed molecular dynamics simulations to study a Gay-Berne discotic fluid confined in a slab geometry for a fixed confinement length. Four different anchoring strengths with a homeotropic (face-on) configuration were studied. We found that changing the anchoring strength changes the normal component of the stress tensor, which in turn changes the density of the system’s bulk. This phenomenon leads to a shift in the isotropic-nematic transition temperature. We observe that the temperature regions where the nematic phase is present diminishes as the anchoring strength increases. The anchoring strength also affects the nematic-columnar coexistence temperature-region: it spans over more temperatures at higher anchoring strengths.
关键词： molecular dynamics simulations,discotic liquid crystals,anchoring strength,phase behaviour,face-on confinement
更新于2025-09-04 15:30:14
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Optical bonding of tellurite glass film on silicate glass
摘要： Tellurite glass thin film was successfully bonded on a silicate glass substrate by the direct bonding (DB) method. Glass film (thickness 1-3 μm) was fabricated by the glass blowing technique and the DB process was performed at room temperature at relative humidity (RH) of 62% or 15%. The surface adhesive strengths of the glass films bonded at 15% and 62% RH were measured as 250 and 96 mJ/m2 respectively by the Obreimoff-Metsik method. The hydroxyl (-OH) functional groups on the interface between the film and silicate glass were analyzed by Fourier transform infrared spectroscopy. The major bonding forces between the tellurite thin film and silicate glass were hydrogen bonds at 62% RH and bonds between Te on the tellurite glass and O on the silicate glass were concerned at 15% RH. These forces, contributed by Si-OH, were important for bond formation at 62%. The large amounts of water and OH groups on the silicate glass, determined by thermogravimetric analysis, indicated a weaker bonding process at 62% RH. This work will contribute toward reliable, high-integrity components for integrated optical circuits, which are increasingly needed for high-throughput data transfer.
关键词： glass thin film,tellurite glass,hydroxyl group,adhesive strength,direct bonding
更新于2025-09-04 15:30:14
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Consequences of Ultra-Violet Irradiation on the Mechanical Properties of Spider Silk
摘要： The outstanding combination of high tensile strength and extensibility of spider silk is believed to contribute to the material’s toughness. Thus, there is great interest in engineering silk for biomedical products such as suture or implants. Additionally, over the years, many studies have also sought to enhance the mechanical properties of spider silk for wider applicability, e.g., by irradiating the material using ultra-violet radiation. However, the limitations surrounding the use of ultra-violet radiation for enhancing the mechanical properties of spider silk are not well-understood. Here, we have analyzed the mechanical properties of spider silk at short ultra-violet irradiation duration. Specimens of spider silk were subjected to ultra-violet irradiation (254-nm wavelength, i.e. UVC) for 10, 20, and 30 min, respectively, followed by tensile test to rupture to determine the strength (maximum stress), extensibility (rupture strain), and toughness (strain energy density to rupture). Controls, i.e., specimens that did not received UVC, were also subjected to tensile test to rupture to determine the respective mechanical properties. One-way analysis of variance reveals that these properties decrease significantly (p < 0.05) with increasing irradiation duration. Among the three mechanical parameters, the strength of the spider silk degrades most rapidly; the extensibility of the spider silk degrades the slowest. Overall, these changes correspond to the observed surface modifications as well as the bond rupture between the peptide chains of the treated silk. Altogether, this simple but comprehensive study provides some key insights into the dependence of the mechanical properties on ultra-violet irradiation duration.
关键词： bond crosslinks,bond scission,extensibility,toughness,strength
更新于2025-09-04 15:30:14