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The restoration of the friction surfaces by laser cladding
摘要： The paper deals with laser cladding of wear-resistant coatings for restoring friction surfaces. It describes the modes of cladding technological process, and presents the results of wear tests. Wear-resistant coating based on the Ni-Cr-B-Si and alumina system, which exceeds 30HGSA steel by 11.5 times by wear resistance.
关键词： wear-resistant coatings,alumina,friction surfaces,Ni-Cr-B-Si,laser cladding
更新于2025-09-23 15:19:57
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[Laser Institute of America ICALEO?? 2017: 36th International Congress on Applications of Lasers & Electro-Optics - Atlanta, Georgia, USA (October 22a??26, 2017)] International Congress on Applications of Lasers & Electro-Optics - Laser direct writing lithography for rapid fabrication on non-planar surfaces
摘要： A modified laser direct writing lithography system with dynamic focusing is presented. This improved system can realize rapid fabrication on non-planar surfaces with large curvature and it offers new possibilities for fabricating micro-patterns on curved surfaces in an easy and fast way. A dynamic focusing lens group which is driven by a linear voice coil motor is introduced and it can rapidly control the laser spot to focus on the curved surface when processing in real-time. The focus range is almost 10 mm and it can be larger when working with the z-stage. The mathematic expression of dynamic focusing is deduced and the corresponding experiment results agree with the numerical analysis, which shows the practicability of the system. The effects of slopes with different tilted angles on exposure linewidth are studied. Finally, a concentric-circle grating is fabricated on a convex substrate with a diameter of 30 mm and a radius of curvature of 19.918 mm. The grating has homogeneous linewidth of 10 μm and line space of 20 μm, and the total processing time is within 40s. This technique can greatly improve the efficiency and has great potentials, such as rapid fabrication of diffractive optical elements (DOEs) or microelectromechanical systems (MEMS) on arbitrary 3D curved surfaces.
关键词： non-planar surfaces,dynamic focusing,micro-patterns,rapid fabrication,laser direct writing lithography
更新于2025-09-23 15:19:57
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Enhanced Goos-H?¤nchen shift of graphene coated on one-dimensional photonic crystal
摘要： The enhancement of Goos-H?nchen shift of graphene coated on a truncated one-dimensional photonic crystal is proposed and theoretically investigated. The proposed band-gap con?guration featuring highly electric ?eld enhancement and con?nement on the graphene surface enables the excitation of Bloch surface wave mode. By taking full advantages of the remarkable optical properties of the excited optical surface wave mode, a large phase variation appears near the band-gap of the proposed structure, leading to a dramatically enhanced Goos-H?nchen shift. Leveraging this giant Goos-H?nchen shift, the sensing capability of this proposed structure is discussed, implicating a superior performance in Goos-H?nchen shift sensing applications.
关键词： Graphene,Optical instruments,Optics at surfaces,One-dimensional photonic crystal
更新于2025-09-23 15:19:57
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[IEEE 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Saint Petersburg, Russia (2018.10.22-2018.10.23)] 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Optical Method for Evaluation of Articular Surface After Chondroplasty in Rabbits
摘要： The paper presents the results of studies of samples of the articular surface of rabbits using the method of Raman spectroscopy. It was found that the values of the optical coefficients are characterized by changes in the intensity of the peaks at the wave numbers 956 cm-1 (PO4 3- (Symmetrical valence oscillations of phosphate)) and 1069 cm-1 (CO3 2- (C-o planar valence)) and relatively constant values of the coefficients at the wave numbers 1250 cm-1 (Amide III) and 1660 cm-1 (Amide I).
关键词： Raman spectroscopy,chondroplasty,articular surfaces
更新于2025-09-23 15:19:57
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All-optical and dynamic manipulation of surface plasmon polaritons by tailoring the polarization state of incident light
摘要： A hybridly polarized vector beam comprising linear, elliptical, and circular polarizations at the beam cross-section is investigated for the manipulation of surface plasmon polaritons (SPPs). Unlike the well-known radially- or azimuthally-polarized beam that only includes linear polarization, this hybridly polarized beam provides increased optical degrees of freedom, which assist in controlling the excitation, orientation, and distribution of the focused SPPs excited in a high-numerical-aperture microscopic configuration. Many fascinating SPP patterns can be easily obtained, such as sharp peaks, multi-foci, donuts, and dark polygons. Those novel properties might be of great value in applications such as plasmonic tweezers.
关键词： electromagnetic wave propagation,polarization,interference,optical properties of surfaces
更新于2025-09-23 15:19:57
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The Rotating Glass Illusion: Material Appearance Is Bound to Perceived Shape and Motion
摘要： We report a novel illusion in which a rotating transparent and refractive triangular prism (glass object) is perceived as being made of a specular reflective material (mirror), and simultaneously, its direction of rotation (clockwise or anticlockwise) is also misperceived. Our findings suggest that physical motion strongly influences viewers’ judgements of material in some situations.
关键词： shapes/objects,surfaces/materials,motion,object recognition
更新于2025-09-19 17:15:36
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Photoluminescence in <i>m</i> -carborane–anthracene triads: a combined experimental and computational study
摘要： New hybrids synthesized by linking two anthracenyl units to the Ccluster atoms of a non- (4), a mono- (5) and a di-iodinated (6) m-carborane fragment through CH2 spacers, along with their full characterization, are reported. Noticeably, bonding the m-carborane fragment to the anthracene moieties produces a significant increase of more than two-fold in the intrinsic fluorescence quantum yield (fF) of the anthracene itself, with values of fF 4 60% in THF and fF 4 48% in toluene, although it does not alter the absorption and emission patterns of the fluorophore in solution. A red-shift of the emission maximum with respect to the solution is observed in the aggregate state (THF/H2O, 1 : 99 v/v), along with moderate quantum yields; compounds 4 and 5 show fF = 22 and 19%, respectively, whereas 6 has a lower value (fF = 8%). The di?erence between the fF values in the aggregate state has been attributed to the arrangement of dimers for each compound in the solid state structures. X-ray crystal structures of compounds 4 and 5 show the anthracene units to be roughly parallel, whereas such an arrangement is clearly disrupted in compound 6. Such di?erences have been analyzed by Hirshfeld surfaces, decomposed fingerprint plots for the three compounds and DFT calculations. The combined results from the supramolecular analyses and DFT studies support the idea that a less delocalized system in the case of 6 can be explained by the di?erent packing in the aggregate or solid state for this di-iodo-derivative. The observed arrangement of molecules of 6 seems to be related to a larger number of H(cid:2) (cid:2) (cid:2)I contacts, with respect to the non-iodinated or mono-iodinated compounds, 4 or 5. According to this assumption, there is a direct relationship between the structure in the solid state and the PL properties; in the m-carborane derivatives, small changes in their structures have caused variations in the photophysical properties, especially in the quantum e?ciency.
关键词： X-ray diffraction,anthracene,m-carborane,Hirshfeld surfaces,photoluminescence,DFT calculations,fluorescence quantum yield
更新于2025-09-19 17:15:36
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A novel miniaturized frequency selective surface
摘要： A novel single layer miniaturized frequency selective surface made of circular unit cell elements is presented in this article. The frequency selective surface (FSS) unit cell measures 0.055λ0 × 0.055λ0, where λ0 corresponds to its free space wavelength. The proposed FSS offers band stop characteristics with bandwidth of 137.5 MHz centered at 1.39 GHz. The symmetrical structure of the unit cell elements provides polarization independency. The miniaturized unit cell elements help achieving angular independency for both TE and TM mode of polarization. The miniaturized design provides excellent angular independency with negligible frequency shift for varying incident angles. A prototype of the FSS is fabricated and its simulation results are validated using measurements.
关键词： polarization,frequency selective surfaces (FSS),miniaturization
更新于2025-09-19 17:15:36
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Polarization-sensitive photoresponse of the CuSe/Se nanocomposite prepared by vacuum thermal deposition
摘要： We report on the generation of the polarization-sensitive photocurrent in the thin film of the CuSe/Se nanocomposite irradiated by femtosecond pulses of Ti:S laser. CuSe/Se bilayer consisting of nanocrystalline CuSe and amorphous Se films was obtained using successive deposition of Cu and Se on a glass substrate in the course of vacuum thermal evaporation. Synthesized bilayers were characterized using optical transmittance and Raman spectroscopy, optical, atomic force and scanning electron microscopy and X-ray diffractometry. It is demonstrated that in the longitudinal configuration, the photocurrent propagating along the plane of incidence is maximum for the p- and vanishes for the s-polarized excitation beam. In the transverse configuration, the photocurrent propagating perpendicular to the plane of incidence is an odd function of the polarization azimuth of the linearly polarized excitation beam and vanishes when it is either p- or s-polarized. We show that for an elliptically polarized excitation beam the polarity of the transverse photocurrent reverses when rotation direction of the electric field vector changes. Both longitudinal and transverse photocurrents are odd functions of the angle of incidence and can be explained in terms of the surface photogalvanic effect.
关键词： CuSe,Surfaces and interfaces,Spin dynamics,Electromotive force,Thin film
更新于2025-09-19 17:13:59
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Wetting angle stability of steel surface structures after laser treatment
摘要： In this work, we have used a nanosecond pulsed fiber laser to modify the wettability characteristics of AISI 430 steel. For this, various surface morphologies were created on the samples by laser irradiation with different overlapping and intensity parameters. Immediately upon laser treatment, all the structured samples acquired either hydrophilic or superhydrophilic wetting angles. All the samples were also analyzed with XRD. Then, laser-treated samples were kept in ambient air and/or low-temperature annealing was applied to reach hydrophobic surface properties. Interestingly, these surfaces returned back practically to their initial wetting state by cleaning in an ultrasonic bath. The obtained results are analyzed based on the existing wettability models.
关键词： Nanosecond laser structuring,Hydrophobic and hydrophilic surfaces,Wettability transition,Wetting angle stability
更新于2025-09-19 17:13:59