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Effect of elastomer characteristics on fiber optic force sensing performance in biomedical robotics applications
摘要： Miniaturized and “smart” sensors are required for research in biology, physiology, and biomechanics, and they have extremely important clinical applications for diagnostics and minimally invasive surgery. Fiber optic sensors have been proven to provide advantages compared to conventional sensors and high potential for biomechanical and biomedical applications. They are small, easy to operate, minimally invasive with low risk, more accurate, and inexpensive. This paper reports the design and modeling of a fiber optic force sensor that is capable of measuring compliance for a contact force of up to 1 N. The main objective of this study is to design and model a fiber optic sensor capable of measuring the total force applied on an object. A polydimethylsiloxane (PDMS) elastomer film with a thickness of 1.2 mm is placed between an optical fiber tip and an object, and it is used for measuring the force applied on a rigid element. The compliance of the fiber optic force sensor is measured by recording the response of PDMS elastomer films under different load conditions. We use finite element modeling results as a basis for comparing experimental data. The agreement between theoretical predictions and experimental data is reasonable and within an acceptable range.
关键词： Force sensor,FEM analysis,Optical fiber,Elastomer,MATLAB analysis,LabVIEW,ANSYS simulation,Biomedical robotics
更新于2025-09-04 15:30:14
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[Micro/Nano Technologies] Micro and Nano Fabrication Technology Volume 1 || Micro Milling for Functional Surface
摘要： Micro manufacturing has recently increased in the several ?elds that include optics, electronics, medicine, biotechnology, and communications. Then, drastic progresses have been seen in the micro milling with the technologies in micro/nano-scale measurement, control, and tooling. This chapter describes the micro milling for manufacturing of the functional surfaces, which control material behavior with the surface topography. In the introduction, the current technical status in the functional surfaces is reviewed with the micro fabrication processes, and some issues in the micro milling are described to achieve high qualities of the micro elements and structures on the surfaces. Then, the typical micro milling process is discussed in terms of the operations and the removal process. Regarding material behavior, the effect of crystal grain size and orientation on the removal process becomes relatively large. When the grain size reduces, the dynamic components in the cutting force, burr formation, and affected layer can be controlled in micro cutting. Micro milling is applied to manufacture the functional surfaces with the micro dimples at high machining rates. The micro dimples are machined in milling with the inclined spindle at 45(cid:1). The milling with the cutter axis inclination is also applied to machine the micro dimples on the cylinder surfaces. A mechanistic model is applied to control the dimple shape for the cutting parameters, the feed direction, and the tool geometry. The surfaces with the micro dimples are applied to control the surface functions such as optical re?ection and wettability.
关键词： Surface function,Micro milling,Micro dimple,Wettability,Mechanistic model,Fine grained steel,Optical control
更新于2025-09-04 15:30:14
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Broadband terahertz ZnO photonic crystals fabricated by 3D printing
摘要： ZnO has been demonstrated to be a promising material for optoelectronic applications in the terahertz (THz) spectral range. However, there have been no reports regarding the fabrication of ZnO structures to control THz radiation, as photonic crystal (PCs) materials. Here, we focus on the development of a functional ZnO PCs for the THz band. The functionality is provided by the design that is based on a woodpile lattice with the appropriate periodicity for the THz region. Using a three-dimensional (3D) printing technique, we fabricate 3D ZnO based PCs with an e?ective lattice constant to generate a bandgap at the THz region. The functionality of the resulting PC was evaluated using THz time-domain spectroscopy combined with theoretical simulations. The results demonstrate the 3D woodpile lattice structure has good optical properties in the THz frequency region. These results serve as a step for the development of new THz functional devices for optoelectronics applications.
关键词： ZnO,Sintering,Extrusion,Optical properties
更新于2025-09-04 15:30:14
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Influence of rare earth material (Sm3+) doping on the properties of electrodeposited Cu2O films for optoelectronics
摘要： Herein, we report samarium (Sm) dopant concentration effect on Cu2O films characteristics prepared by electrodeposition method. XRD patterns of the films indicated that pristine and Sm:Cu2O films have polycrystalline cubic structure with (111) preferred orientation. It was seen from the SEM photographs pinhole free dense triangle shaped grains for undoped Cu2O thin films and the grain size was decreased as concentration of samarium was increased. Raman spectroscopy showed peaks at 108, 146, 217, 413 and 637 cm?1 which conformed the Cu2O phase formation and intensity of the peaks was decreased with a increase in dopant concentration. UV–Vis spectra exhibited that the absorption value of Cu2O films is increased gradually with reduction in band gap value for the increase of samarium content. Photoluminescence (PL) spectra revealed that all films display a visible light emissions and its intensity was reduced due to increase in doping concentration. Photosensitivity observation study indicated that the photocurrent of deposited Cu2O films was increased along with the increase in dopant material concentration.
关键词： Electrodeposition,Cu2O films,Optoelectronics,Structural properties,Samarium doping,Optical properties,Photosensitivity
更新于2025-09-04 15:30:14
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State Primary Standard GET 156-2015 of Units of Spectral Coefficients of Directional Transmission, Diffuse and Specular Reflections in the Wavelength Range from 0.2 to 20.0 μm
摘要： We present the composition of the State Primary Standard GET 156-2015 of units of the spectral coefficients of directional transmission, diffuse and specular reflections in the wavelength range from 0.2 to 20.0 μm. Metrological characteristics of the standard are given.
关键词： specular reflection,diffuse reflection,directional transmission,key comparisons,spectrophotometry,optical properties of materials
更新于2025-09-04 15:30:14
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Nonlinear absorption and Optical limiting of Ag–CdSe nano-hybrids of different growth times
摘要： Metal-semiconductor Nano-composites have enormous applications due to Plasmon –exciton coupling. Open aperture Z-scan is investigated for Ag–CdSe hybrid nanostructure, a toggle from saturable absorption process SA to reverse saturable absorption RSA is observed upon laser power increment. Proofs of crystal and morphological structure are given by selected area electron diffraction (SAED) and high resolution transmission electron microscope (HRTEM). Red shifting in photoluminescence spectra PL is observed which is ascribed to the particle size increment. Intriguing nonlinear findings can be used to engineer optical switching devices and optical limiters.
关键词： Photoluminescence,Open aperture Z scan,Ag:CdSe,Metal semiconductor nanohyrid structure,Optical limiting,Nonlinear absorption coefficient
更新于2025-09-04 15:30:14
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Enhancing the Secrecy Performance of the Spatial Modulation Aided VLC Systems with Optical Jamming
摘要： In order to enhance the secrecy performance of the spatial modulation (SM) aided visible light communication (VLC) system, an optical jamming aided secrecy enhancement scheme is proposed in this paper, in which transmitter (Alice) sends the optical jamming signals and the con?dential signals simultaneously with amplitude and power constraints, wherein the truncated Gaussian distribution is adopted by the optical jamming signals for the considered constraints. Additionally, with ?nite discrete support set of the channel inputs’ distribution, the corresponding secrecy performance is systematically analyzed for the optical jamming aided SM-VLC system, which includes the average mutual information (AMI), the lower bound on AMI and its closed-form expression approximation and the achievable secrecy rate. Furthermore, the power allocation problem for the proposed SM-VLC systems with optical jamming is considered. Finally, extensive simulation results are presented to validate our analytical results and the secrecy versus bit error ratio (BER) trade-off is characterized.
关键词： physical layer security (PLS),Visible light communication (VLC),spatial modulation (SM),power allocation,achievable secrecy rate,optical jamming
更新于2025-09-04 15:30:14
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Controllable competitive nanocrystallization of La3+-based fluorides in aluminosilicate glasses and optical spectroscopy
摘要： Glass ceramic has been regarded as an alternative to traditional bulk materials such as single crystal and transparent ceramic. The nucleation/growth behavior of glass ceramic via crystallization is an important topic but is seldom studied so far. In the present work, a series of La3+-based oxyfluoride aluminosilicate glasses are designed to understand their nanocrystallization processes upon heating. Impressively, controllable LaF3, α-NaLaF4 and β-NaLaF4 phase-competitive crystallization in glasses is achieved and structural/spectroscopic characterizations confirm the key role of Al/Si ratio to determine the release of Na+ ions from glass network to participate in crystallization and phase transformation. Furthermore, the developed glass ceramics are evidenced to be ideal hosts for lanthanide dopants (such as Eu3+ and Yb3+/Er3+), which can effectively incorporate into the precipitated fluoride crystal lattices by substituting La3+ ions. As a consequence, incoherent LED-excitable upconverting devices are constructed to demonstrate their promising application as emitting media in display.
关键词： Luminescence,Glass ceramics,NaLaF4,Optical materials,Upconversion
更新于2025-09-04 15:30:14
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Systematic analysis of the fine structure of energy level structures and spin-Hamiltonian parameters of V3+ ion in corundum with dynamic Jahn-Teller effect
摘要： Systematic analysis of fine structure of the whole energy levels and spin-Hamiltonian parameters ( zero-field splitting (ZFS) parameter D and g-factors g// and g?) for the ground state 3A2 ( 3T1 ) of V3+ ion in corundum are presented in detail with complete diagonalization method (CDM) of 45×45 energy matrix, in which the full configuration interactions are taken in account . The reduction of the splittings of excited electronic 3T2 ( t2ge ) term with orbital triplet degenerate caused by spin-orbit (SO) and lower trigonal crystal field (CF) is studied by T2?e model dynamic Jahn-Teller theory, and Ham deduction factor , the Jahn-Teller energy EJT and Huang-Rhys factor S are estimated. The studies are performed within the strong-field scheme with molecular orbit (MO) approximation, in which the two SO coupling parameter model is used and the SO contributions from both the central 3d ion and ligands are taken in account.The calculated results are in good agreement with the experimental data, and the local structure of [VO6]9- cluster with C3 point group symmetry are determined quantitatively.
关键词： Dynamic Jahn-Teller effect,Electron paramagnetic resonance,V3+ ion,Optical spectrum,Complete diagonalization method
更新于2025-09-04 15:30:14
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Y2(CO3)3?H2O and (NH4)2Ca2Y4(CO3)9?H2O: Partial Aliovalent Cation Substitution Enabling Evolution from Centrosymmetry to Noncentrosymmetry for Nonlinear Optical Response
摘要： An effective approach, the partial aliovalent cation substitution (PACS), was successfully employed to develop nonlinear optical (NLO) material. Two novel rare earth carbonates, Y2(CO3)3·H2O (YC) and (NH4)2Ca2Y4(CO3)9·H2O (CYC), were synthesized, which feature the same honeycomb-like framework structure. From YC to CYC, the partial substitution of Y3+ with Ca2+ led to the evolution of space group from centrosymmetric P63/mcm to noncentrosymmetric P63mc. The CYC exhibited a second harmonic generation (SHG) effect of 2.1 × KH2PO4 (KDP) and a deep-UV cut-off edge (<200 nm). It was concluded that the SHG effect originates from the ordered arrangement of (CO3)2- groups and the dipole polarization enhancement of [Ca0.33Y0.67O9] polyhedra. Specifically, the long-range ordered electric field of channels induced the ordered arrangement of (CO3)2- groups. This synthetic approach and SHG-activated induction mechanism may afford new strategies for the design and synthesis of NLO materials.
关键词： nonlinear optical materials,partial aliovalent cation substitution,rare earth carbonates,deep-UV cut-off edge,second harmonic generation
更新于2025-09-04 15:30:14