Spherical Fiber Research Articles

An elementary approach to local combinatorial formulae for the Euler class of a PL spherical fibre bundle

We present an elementary approach to local combinatorial formulae for the Euler class of a fibre-oriented triangulated spherical fibre bundle. This approach is based on sections averaging technique and very basic knowledge of simplicial (co)homology theory. Our formulae are close relatives of those due to Mnëv. Bibliography: 9 titles.

An elementary approach to local combinatorial formulae for the Euler class of a PL spherical fibre bundle

Описан элементарный подход к локальным комбинаторным формулам для класса Эйлера послойно ориентированного триангулированного сферического расслоения. Подход основан на технике усреднения сечений и требует лишь базовых знаний теории симплициальных (ко)гомологий. Наши формулы родственны формуле Н. Мнeва. Библиография: 9 названий.

A Note on a Local Combinatorial Formula for the Euler Class of a PL Spherical Fiber Bundle

We present a local combinatorial formula for the Euler class of a $n$-dimen\-si\-onal PL spherical fiber bundle as a rational number $e_{\it CH}$ associated to a chain of $n+1$ abstract subdivisions of abstract $n$-spherical PL cell complexes. The number $e_{\it CH}$ is a combinatorial (or matrix) Hodge theory twisting cochain in Guy Hirsch's homology model of the bundle associated with PL combinatorics of the bundle.

Silicone Rubber Fabry-Perot Pressure Sensor Based on a Spherical Optical Fiber End Face.

To improve the fringe contrast and the sensitivity of Fabry-Perot (FP) pressure sensors, a silicone rubber FP pressure sensor based on a spherical optical fiber end face is proposed. The ratio of silicone rubber ingredients and the diameter and thickness of silicone rubber diaphragm were optimized by a simulation based on experimental tests that analyzed elastic parameters, and the influence of the radius of a spherical optical fiber and the initial cavity length of the sensor on the fringe contrast was investigated and optimized. Pressure sensor samples were fabricated for pressure test and temperature cross-influence test. Gas pressure experimental results within a pressure range of 0~40 kPa show the average sensitivity of the sensor is −154.56 nm/kPa and repeatability error is less than 0.71%. Long-term pressure experimental results show it has good repeatability and stability. Temperature experimental results show its temperature cross-sensitivity is 0.143 kPa/°C. The good performance of the proposed FP pressure sensor will expand its applications in biochemical applications, especially in human body pressure monitoring.

Label-free fiber-optic spherical tip biosensor to enable picomolar-level detection of CD44 protein

Increased level of CD44 protein in serum is observed in several cancers and is associated with tumor burden and metastasis. Current clinically used detection methods of this protein are time-consuming and use labeled reagents for analysis. Therefore exploring new label-free and fast methods for its quantification including its detection in situ is of importance. This study reports the first optical fiber biosensor for CD44 protein detection, based on a spherical fiber optic tip device. The sensor is easily fabricated from an inexpensive material (single-mode fiber widely used in telecommunication) in a fast and robust manner through a CO2 laser splicer. The fabricated sensor responded to refractive index change with a sensitivity of 95.76 dB/RIU. The spherical tip was further functionalized with anti-CD44 antibodies to develop a biosensor and each step of functionalization was verified by an atomic force microscope. The biosensor detected a target of interest with an achieved limit of detection of 17 pM with only minor signal change to two control proteins. Most importantly, concentrations tested in this work are very broad and are within the clinically relevant concentration range. Moreover, the configuration of the proposed biosensor allows its potential incorporation into an in situ system for quantitative detection of this biomarker in a clinical setting.

Low-Cost Fiber Optic Cantilever Accelerometer With a Spherical Tip Based on Gaussian Beam Focusing

We propose and demonstrate a low-cost and simple fiber optic cantilever accelerometer with a spherical tip based on Gaussian beam focusing. The accelerometer consists of ceramic ferrule, ceramic sleeve, receiving fiber and emitting fiber, where both fibers are single mode fiber, the ferrule and sleeve have characteristics of high precision, which reduce the difficulty of optical alignment. The end of the emitting fiber is made into a spherical tip for focusing the Gaussian beam to improve sensitivity. When the accelerometer is in operation, the emitting fiber acts as a cantilever beam, the acceleration can be measured by detecting the transmission power. Further, our experimental results show that the spherical fiber tip can improve the acceleration sensitivity by 67% over 10 Hz-1000 Hz without reducing the working bandwidth. In addition, it is found that the fiber accelerometer has a high signal-to-noise ratio (SNR) up to 60 dB, and a low harmonic distortion of better than -30 dB, rendering a quasi-8-shaped directionality at the working frequency ranging from 10 Hz to 1200 Hz. This clever sensor structure may have potentials for developing high-performance and cost-effective accelerometers and hydrophones.

Performance of Topological Perception in the Myopic Population

ABSTRACT Purpose: Discriminating objects’ topological property (TP) is a primitive function of visual representation, which is reported to be associated with magnocellular (M) visual pathway, temporal lobe (TL), and superior colliculus (SC)-pulvinar subcortical pathway. Previous studies have shown that M pathway and TL were affected in high myopia (HM) subjects. The study was accordingly designed to explore whether topological perception performance was abnormal in HM subjects. Methods: 30 mildly myopic, 25 moderately myopic, 35 highly myopic, and 20 emmetropic subjects were enrolled. All participants underwent a comprehensive ophthalmological assessment including automated refraction, intraocular pressure, Humphrey 10–2 standard automated perimetry, ocular fundus photography and swept-source optical coherence tomography. Defined by differences in hole, TP and non-TP discrimination with letters “E”, “S”, “P”, “d” as stimuli in the central and peripheral regions was performed using the MATLAB 2017 software. d-primes extracted from the software were analyzed within each group. The correlation of peripheral TP/non-TP deficit with spherical equivalent (SE), axial length (AL) and average peripapillary retinal nerve fiber layer (RNFL) thickness was performed. Results: The patterns of topological perception performance were similar among the groups. TP discrimination peripherally was significantly better than that centrally in the mild myopia (P < .001), moderate myopia (P < .001), high myopia (P < .001) and emmetropia groups (P = .001). In the peripheral region, TP d-prime scores were significantly better than non-TP d-prime scores (all P < .001). The main and interaction effects of eccentricity and stimulus type were statistically significant(P < .05). There was no statistically significant correlation between peripheral TP/non-TP deficit and SE, AL or average RNFL thickness (P > .05). Conclusions: The current study first showed that patterns of topological perception among the myopic population were similar and not affected by the severity of myopia.

球形端面光纤与黑体光源耦合效率分析

球形端面光纤与黑体光源耦合效率分析

Differential Incremental Equilibrium Geometry-Effects of Cerebral Groove and Protein Granule Motion on Thinking Space and Mental Activity

The research direction of this paper is to construct brain-like spatial structure and brain, nervous system and neurotransmitters from molecular cytobiology to construct mental acquisition from the influence of neuron and genome expression on brain, especially the material suspension caused by mental collapse to the neuron-like topological spatial structure and fluid topological structure of neurotransmitters. The spatial construction of acquired immunity and fluid morphology of neurotransmitters in the field of psychiatry (Carrying schizophrenia and other factors) also has brain-like mental activity traits. Stable traceability of neurotransmitter structure of series signal in schizophrenics with advanced intelligence. The high-end hyperspherical convex spherical fiber bundles with reduced dimension in 3+1 dimension system, special light field with radiation, and the collapse of mental force cause the suspension of substance in stationary state, the similar solution of solitary wavelet of petal-like micro-fibers in superimposed bundles. That is to say, the intelligent information particles carrying special image fragments in the form of mental energy in Psychological Acquired Immunity. Including primitive and innovative mathematical models of neuronal cell modification. Therefore, on the basis of original mathematical "differential incremental equilibrium geometry". The geometric models of spatial geometry and fluid structure of neurotransmitters of all neurons in life sciences are solved at the molecular level. Even using the nonlinearity of 4-dimensional super-high-end super-spherical convex fiber plexus "redundancy, petal-like micro-fibers" Sex-like solitary wavelet, which truly establishes the internal structure and law of molecular cell biology model. Reflects the new field of human brain research. It provides the basis and precondition of theory and application for the establishment of hybrid artificial intelligence of life and machine. and has far-reaching influence and important development prospects for the development of artificial intelligence, especially in brain-like artificial intelligence.

Equivalent inclusion approach and approximations for conductivity of isotropic matrix composites with sphere-like, platelet, and fibrous fillers

The construction starts from certain typical effective medium approximations for conductivity of idealistic isotropic matrix composites with randomly oriented inclusions of perfect spherical, platelet, and circular fiber forms, which obey Hashin–Shtrikman bounds over all the ranges of volume proportions of the component materials. Equivalent inclusion approach is then developed to account for possible diversions, such as non-idealistic geometric forms of the inhomogeneities, imperfect matrix-inclusion contacts, filler dispersions, and when the particular values of the fillers’ properties are unspecified, using available numerical or experimental reference conductivity data for particular composites. Illustrating applications involving experimental data from the literature show the usefulness of the approach.

Analysis of a novel design of uniformly illumination for Fresnel lens-based optical fiber daylighting system

Recently, advanced daylighting has become an important part of sustainable architecture design to increase visual comfort and illuminate deep interior spaces. Daylighting systems based on solar concentrators and fiber optical transmission have attracted a lot of research attention. In this paper, the authors propose a daylight collection and transmission design to transmit the concentrated light more uniformly into the optical fibers employing two optical elements: an eight-fold Fresnel lens as the primary optical element (POE) and an octagonal spherical fiber connector as the secondary optical element (SOE). In addition, a bi-layer prismatic optical panel acting as a diffuser is proposed in order to distribute light more uniformly in the interior space. The proposed designs of those optical elements are verified by ray-tracing simulation for achieving the required illumination level. The simulation results have shown that the combination of the proposed POE and SOE transmits light more uniformly into the bundle of optical fibers, and meanwhile the light diffuser provides relatively even illuminance distribution on a working plane. This shows a considerable advancement to the optical fiber daylighting designs. A case study shows the transmission efficiency of the proposed design is about 10% better than other common designs.

Simultaneous measurement of trace organic vapors and temperature by use of zeolite thin film-coated fiber spherical end face and fiber Bragg grating

Simultaneous measurement of trace organic vapors and temperature by use of zeolite thin film-coated fiber spherical end face and fiber Bragg grating

Fiber‐Optic Probes for Small‐Scale Measurements of Scalar Irradiance

A new method for producing fiber-optic microprobes for scalar irradiance (=fluence rate) measurements is described. Such fine-scale measurements are important in many photobiological disciplines. With the new method, it is possible to cast spherical 30-600 μm wide light integrating sensor tips onto tapered or untapered optical fibers. The sensor tip is constructed by first casting a clear polymethyl methacrylate (PMMA) sphere (~80% of the size of the final probe tip diameter) onto the optical fiber via dip-coating. Subsequently, the clear sphere is covered with light diffusing layers of PMMA mixed with TiO2 until the fiber probe exhibits a satisfactory isotropic response (typically ±5-10%). We also present an experimental setup for measuring the isotropic response of fiber-optic scalar irradiance probes in air and water. The fiber probes can be mounted in a syringe equipped with a needle, facilitating retraction of the spherical fiber tip. This makes it, e.g. possible to cut a hole in cohesive tissue with the needle before inserting the probe. The light-collecting properties of differently sized scalar irradiance probes (30, 40, 100, 300 and 470 μm) produced by this new method were compared to probes produced with previously published methods. The new scalar irradiance probes showed both higher throughput of light, especially for blue light, as well as a better isotropic light collection over a wide spectral range. The new method also allowed manufacturing of significantly smaller scalar irradiance microprobes (down to 30 μm tip diameter) than hitherto possible, and such sensors allow minimally invasive high-resolution scalar irradiance measurements in thin biofilms, leaves and animal tissues.

Singularimetry of local phase gradients using vortex lattices and in-line holography

We have developed a differential form of singularimetry, which utilizes phase vortices or intensity gradient singularities as topological fiducial markers in a structured illumination context. This approach analytically measures phase gradients imparted by refracting specimens, yielding quantitative information that is both local and deterministic. We have quantified our phase gradient experiments to demonstrate that lattices of wave field singularities can be used to detect subtle phase gradients imparted by a spherical specimen and fiber optic cylinders.

Plasma in-liquid method for reduction of zinc oxide in zinc nanoparticle synthesis

Metal air-batteries with high-energy density are expected to be increasingly applied in electric vehicles. This will require a method of recycling air batteries, and reduction of metal oxide by generating plasma in liquid has been proposed as a possible method. Microwave-induced plasma is generated in ethanol as a reducing agent in which zinc oxide is dispersed. Analysis by energy-dispersive x-ray spectrometry (EDS) and x-ray diffraction (XRD) reveals the reduction of zinc oxide. According to images by transmission electron microscopy (TEM), cubic and hexagonal metallic zinc particles are formed in sizes of 30 to 200 nm. Additionally, spherical fiber flocculates approximately 180 nm in diameter are present.

Analysis of orientation and tensor properties of airborne fibrous particle flow

Purpose – The purpose of this paper is to study the effect of particle shapes (spherical particle and nonspherical fiber) on their orientation distributions in indoor environment. Design/methodology/approach – This paper adopted a particle model to predict the fibrous particle flow and distribution, and analyzed the orientation distributions of nonspherical fiber particles and spherical particles in airflows like indoor places. Fokker-Planck model was employed to solve the orientation behavior of nonspherical fiber particles. Findings – The simulation results discover that the nonspherical airborne fiber particles have very different characteristics and behaviors and their orientation distributions are totally different from the uniform distribution of spherical particles. The investigation of the particle orientation tensor and orientation strength indicates that the airflow field becomes more anisotropic due to the suspended fibers. The airborne fiber particles increase the viscosity of the room airflow due to the fiber induced additional viscosity. Originality/value – Orientation tensor, strength and additional viscosity in fibrous flow are seldom investigated indoor. This research reveals that the particle shape has to be considered in the analysis of particle transport and distribution in indoor places as most suspended indoor particles are nonspherical.

A general exact solution for heat conduction in multilayer spherical composite laminates

In this study, an exact analytical solution for steady conductive heat transfer in multilayer spherical fiber reinforced composite laminates is presented as the first time. Here, the orthotropic temperature distribution of laminate is obtained under the general linear boundary conditions that are suitable for various conditions including combinations of conduction, convection, and radiation both inside and outside of the sphere. The temperature and heat flux continuity is applied between the laminas. In order to obtain the exact solution, the separation of variables method is used and the set of equations related to the coefficient of Fourier–Legendre series of temperature distribution is solved using the recursive Thomas algorithm. The capability of the present solution is examined by applying it on two industrial applications for different fiber arrangements of multilayer spherical laminates.

球形光纤传输三维电场传感器

球形光纤传输三维电场传感器

Theoretical Treatments for the Butt-Coupling Characteristics of Fibers

For the butt-joint coupling between a single mode fiber (SMF) and a single mode dielectric slab waveguide (SMDSW) with a spherical fiber micro-lens (SFML), the influence of aberration on the propagation characteristics and coupling efficiencies of the coupler are investigated using the Monte Carlo simulation. The simulation results show that because of the spherical aberration effects, the location of the waist of the focused beam is nearer to the geometrical focus than that of the aberration free fiber micro-lens (AFFML), and so the coupling efficiencies are less and the curves are platter with respect to the AFFML.

Monte Carlo simulation for coupling between single-mode fiber and slab waveguide with spherical fiber microlenses

For the butt-joint coupling between a single mode fiber (SMF) and a single mode dielectric slab waveguide (SMDSW) with a spherical fiber microlens (SFML), because the SMF and the rectangular-section SMDSW have different symmetry, it is difficult to calculate the coupling efficiencies using the traditional analytic method. In this paper, a Monte Carlo model of the coupler is proposed. This model incorporates the geometrical surface of both the SFML and the SMDSW, the relative position of the SMF and the SMDSW, and both the aberration and diffraction effects into consideration. The propagation characteristics of the coupler are simulated. And the coupling efficiencies and misalignment loss are investigated.