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Fraction of Rare-Earth (Sm/Nd)-Lanthanum Ferrite-Based Perovskite Ferroelectric and Magnetic Nanopowders
摘要： Multiferroic compound, especially LaFeO3-based perovskite nanopowders that exhibit robust simultaneous ferromagnetism and ferroelectricity, are widely investigated and applied in different applications. In this work, we report the synthesis and characterization pertaining to fraction of rare-earth (Sm/Nd)-substituted lanthanum ferrite based perovskite nanopowders via solid-state technique. The multiferroic phenomenon is the fundamental approach to combine both the ferromagnetic and ferroelectric properties in a single system. Reduction in crystallite size, as well as some lattice distortion effects, are included to show the possibilities of tuning the lattice structure, electrical, optical as well as the magnetic properties which are closely connected to the ferroelectric behavior and magnetism. At room temperature, the ferroelectric behavior of La0.9(Sm/Nd)0.1FeO3 exhibiting a P-E hysteresis loop became more and more pronounced, indicating the electrical leakage is greatly reduced. The canted antiferromagnetic hysteresis loop shows that the rare-earth (Sm/Nd) ion can significantly affect the magnetic parameters of the materials.
关键词： Lanthanum ferrite,x-ray diffraction,optical and magnetic properties,solid-state reaction,ferroelectric,UV–Vis spectroscopy
更新于2025-09-23 15:23:52
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low-coherent optical diffraction tomography by angle-scanning illumination
摘要： Temporally low-coherent optical diffraction tomography (ODT) is proposed and demonstrated based on angle-scanning Mach–Zehnder interferometry. Using a digital micromirror device based on diffractive tilting, the full-field interference of incoherent light is successfully maintained during every angle scanning sequences. Further, current ODT reconstruction principles for temporally incoherent illuminations are thoroughly reviewed and developed. Several limitations of incoherent illumination are also discussed, such as the nondispersive assumption, optical sectioning capacity, and illumination angle limitation. Using the proposed setup and reconstruction algorithms, low-coherent ODT imaging of plastic microspheres, human red blood cells, and rat pheochromocytoma cells is experimentally demonstrated.
关键词： quantitative phase imaging,low-coherent,optical diffraction tomography,coherent noise
更新于2025-09-23 15:23:52
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Designing bacterial chemotactic receptors guided by photonic femtoliter well arrays for quantifiable, label-free measurement of bacterial chemotaxis
摘要： Whole cell bioreporters, such as bacterial cells, can be used for environmental and clinical sensing of specific analytes. However, the current methods implemented to observe such bioreporters in the form of chemotactic responses heavily rely on microscope analysis, fluorescent labels, and hard-to-scale microfluidic devices. Herein, we demonstrate that chemotaxis can be detected within minutes using intrinsic optical measurements of silicon femtoliter well arrays (FMAs). This is done via phase-shift reflectometric interference spectroscopic measurements (PRISM) of the wells, which act as silicon diffraction gratings, enabling label-free, real-time quantification of the number of trapped bacteria cells in the optical readout. By generating unsteady chemical gradients over the wells, we first demonstrate that chemotaxis towards attractants and away from repellents can be easily differentiated based on the signal response of PRISM. The lowest concentration of chemorepellent to elicit an observed bacterial response was 50 mM, while the lowest concentration of chemoattractant to elicit a response was 10 mM. Second, we employed PRISM, in combination with a computational approach, to rapidly scan for and identify a novel synthetic histamine chemoreceptor strain. Consequently, we show that by using a combined computational design approach, together with a quantitative, real-time, and label-free detection method, it is possible to manufacture and characterize novel synthetic chemoreceptors in Escherichia coli (E. coli).
关键词： diffraction,synthetic biology,optical biosensor,chemotaxis,microstructures
更新于2025-09-23 15:23:52
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Structural, morphological, composition and optical properties of undoped zinc oxide thin films prepared by spray pyrolysis method: effect of solution concentrations
摘要： The aim of this paper is the study of transparent undoped zinc oxide thin films obtained by spray pyrolysis technique on glass substrates heated at 350 °C from 0.1 to 0.4 mol solution concentrations using zinc acetate dehydrate as precursor. The X-ray diffraction patterns and Raman spectrometry with respect to Urbach energy and wurtzite structure, show that the maximum value of the high frequency intensity E2 and the optimal value of the optical gap are obtained at 0.2 mol concentration. Furthermore, an appropriate transparency is obtained and that makes these films suitable for photovoltaic windows layer cells.
关键词： X-ray diffraction,ultraviolet transmission spectroscopy,Raman spectroscopy,spray pyrolysis,undoped zinc oxide
更新于2025-09-23 15:23:52
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Scattering of electromagnetic waves by a perfect electromagnetic conductor half-screen
摘要： The diffraction of plane electromagnetic waves by a perfect electromagnetic conductor half-screen is investigated. The total geometrical optics fields are obtained by using the boundary conditions of a perfect electromagnetic conductor surface. A general relation is defined for the scattered fields in terms of waves by soft and hard surfaces. The total scattered field is derived by using this relation. Some numerical simulations are also given.
关键词： Perfect electromagnetic conductor,Geometric optics,Diffraction theory
更新于2025-09-23 15:23:52
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Determination of diffraction time and influence of strip moving speeds on texture measurement using X-ray area detector
摘要： In this study, the two most important factors, diffraction time and the influence of the strip moving speed on diffraction accuracy, are analyzed using a laboratory two-dimensional X-ray diffraction system. The results indicate that 2 s is a diffraction time that satisfies both requirements of detection speed and accuracy. The strip moving speed has a certain influence on the detection accuracy, but the influence of the strip moving speed on the diffraction accuracy can be neglected within a strip moving speed of 0.65 m/s. The measurement of online texture and mechanical properties, combined with the fast texture detection theory and mechanical properties calculation model, can be realized in a steel production factory.
关键词： fast texture detection,diffraction time,X-ray area detector,strip moving speeds
更新于2025-09-23 15:23:52
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Dielectric and Transport Properties of Strontium Modified Calcium Copper Titanate
摘要： The present article provides the detailed study of the effect of strontium on the structural, microstructural, dielectric and electrical characteristics of strontium modified calcium copper titanate (i.e. Ca0.95Sr0.05Cu3Ti4O12, referred as CSCTO further) synthesized by a cost-effective ceramic processing technology. The structural analysis carried out suggests a cubic symmetry in the prepared sample. The dielectric relaxation and electrical conduction mechanism of CSCTO were studied using various powerful spectroscopic tools (i.e dielectric and impedance). Study of temperature dependence of dielectric permittivity exhibits very high (giant) dielectric permittivity (5 (cid:1) 103) and low loss factor at low frequency (1 kHz) at an intermediate temperature (315 (cid:3)C). Structure–properties relationship and conduction mechanism have been studied in a wide frequency (103–106 Hz) and temperature (25–315 (cid:3)C) range. At region of low frequency and high temperatures, there is a dominant role of the interface and Maxwell–Wagner dielectric relaxation mechanism in CSCTO bulk ceramic. The grain, grain boundary and electrode contributes towards the capacitive and resistive property of the sample are discerned from Nyquist plot. The ferroelectric (P–E) loop of the sintered CSCTO bulk sample at room temperature showed a lossy hysteresis loop. These findings further promote the capabilities of CSCTO as a base for supercapacitor.
关键词： X-Ray diffraction,supercapacitor,ferroelectric phase,microstructure,dielectric properties
更新于2025-09-23 15:23:52
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Stimuli responsive diffraction gratings in soft-composite materials
摘要： Diffraction gratings (DGs) are unique optical components with the capability to control and address a travelling light wave because of their micro/nanoscale periodicity. Nowadays, DGs are used in several sophisticated and high-tech applications such as spectrometers, memories, as well as in bioengineering and telecommunications. Advanced micro and nano fabrication processes enable the realization of DGs with excellent morphological and optical properties. However, realizing DGs with on-demand optical parameters is still a challenge because of the absence of reliable and cost-effective smart materials. Herein, we discuss the unique and compelling opportunities obtained by bridging materials with intrinsic flexibility (soft polymers) and re-configurability (liquid crystals (LCs)), as well as emerging fabrication procedures. Further, we present several stimuli responsive DGs used in various research fields such as sensing, biotechnology and solar energy. Lastly, in the light of flexible and reconfigurable DGs applications, we report different examples of light responsive and electro-activated, LCs based, DGs.
关键词： photolithography,liquid crystals,diffraction gratings,optics
更新于2025-09-23 15:23:52
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Synthesis of Bismuth Ferrite BiFeO <sub/>3</sub> by solution combustion method
摘要： In this work we describe the synthesis of bismuth ferrite BiFeO3 (BFO) by the method of combustion in solution. Using the techniques of X-ray diffraction (XRD) together with its refinement Rietveld reveals the existence of a distorted rhombohedral perovskite structure (Space group-R3c). The average size of the BFO crystallite was estimated from the half-height width of the X-ray diffraction peaks using the Scherrer’s equation. The morphology of the prepared sample was determined by scanning electron microscopy (SEM) and stoichiometry ratio of BFO was determined by energy dispersive spectroscopy (EDS)
关键词： BFO,X-Ray Diffraction (XRD),Combustion synthesis,Multiferroics
更新于2025-09-23 15:23:52
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Mastering Lateral Radiation Losses in Tunable VCSELs
摘要： This paper deals with the loss mechanisms in tunable vertical-cavity surface-emitting lasers (VCSELs). The strong increase of the threshold gain at the tuning range edges motivates the investigation of the degradation mechanisms presented in this paper. A campaign of simulations performed with our in-house VCSEL ELectroMagnetic (VELM) simulation code, combined with a novel approach based on the study of the Poynting vector, allowed to identify significant lateral radiation losses. The proposal of technology-affordable countermeasures rests on the proper understanding of these phenomena.
关键词： lateral radiation losses,scattering losses,Tunable VCSELs,diffraction
更新于2025-09-23 15:23:52