Modulated Phase Research Articles

Fault-Tolerant Control of a Triple Redundant PMA-SynRM for Minimum Torque Ripple

In this paper, a new fault-tolerant control (FTC) strategy based on minimum torque ripple is proposed for a triple redundant permanent magnet assisted synchronous reluctance motor under single-phase and double-phase faults. Different from removing the faulty modules (single six-phase (S6) operation or single three-phase (S3) operation), the proposed strategy makes full use of the healthy phase of the faulty modules. By precisely controlling the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d-q</i> axes currents of each module, the ripple of permanent magnet torque and reluctance torque can be suppressed simultaneously, thus achieving the minimum output torque ripple. Moreover, the ratio ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> ) of the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">d-q</i> axes current to the stator current can be determined under the constraint of minimum copper loss. In addition, by changing the ratio <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</i> , the proposed strategy can be combined with S6 or S3 strategy to achieve the minimum copper loss in a wide torque range. In summary, the proposed FTC strategy not only achieves the minimum torque ripple but also ensures the minimum copper loss. Finally, experiments are carried out to verify the accuracy and validity of the theory.

Synchronized measurement method for urban distribution networks based on proportional-integral control

In the context of the rising prevalence of renewable energy, the need for precise and synchronized measurements in urban distribution networks has become increasingly critical. Conventional synchronization techniques, which predominantly depend on Global Navigation Satellite System (GNSS) timing signals, are often plagued by significant sampling time errors. Addressing this challenge, this study introduces an innovative automatic synchronization measurement method employing proportional-integral (PI) control. This method is composed of three integral components: the monitoring of local clock phases via pulses per second (PPS) signals, modulation of the clock phase through a PI controller, and the estimation of grid phasors from the synchronized sampled data. The test results of this method on a hardware platform demonstrate its capability to significantly reduce the sampling error from 2 × 10−3 V to an impressive 1 × 10−5 V, while also meeting the requirements of the synchronized phasor measurement standards outlined in C37.118.1. These advancements underscore the significant potential of PI-controlled simultaneous sampling in enhancing the operational efficiency and reliability of urban distribution networks, particularly in environments with a high integration of renewable energy sources.

Spatially nonuniformly correlated vortex beams and their arrays

We introduce a class of partially coherent sources with spatially nonuniformly correlation properties and an off-axis helicoidal phase. It is shown that the unique correlation and phase properties of such sources lead to radiated fields with extraordinary propagation characteristics, such as dark hollow with zero central intensity, self-focusing and lateral self-shifting light intensity. Based on such novel random sources, two types of nonuniformly correlated vortex beam arrays with radial and rectangular symmetry are explored. Analytical and numerical investigations for the evolutions of such light fields are made by the model decomposition representation of correlation function and fast Fourier transform method. The results demonstrate new opportunities for modeling off-axis self-focusing vortex beams and other beam shaping applications by joint modulation of coherence and phase.

Mechanical Rippling for Diverse Ferroelectric Topologies in Otherwise Nonferroelectric SrTiO_{3} Nanofilms.

Polar topological structures such as skyrmions and merons have become an emerging research field due to their rich functionalities and promising applications in information storage. Up to now, the obtained polar topological structures are restricted to a few limited ferroelectrics with complex heterostructures, limiting their large-scale practical applications. Here, we circumvent this limitation by utilizing a nanoscale ripple-generated flexoelectric field as a universal means to create rich polar topological configurations in nonpolar nanofilms in a controllable fashion. Our extensive phase-field simulations show that a rippled SrTiO_{3} nanofilm with a single bulge activates polarizations that are stabilized in meron configurations, which further undergo topological transitions to Néel-type and Bloch-type skyrmions upon varying the geometries. The formation of these topologies originates from the curvature-dependent flexoelectric field, which extends beyond the common mechanism of geometric confinement that requires harsh energy conditions and strict temperature ranges. We further demonstrate that the rippled nanofilm with three-dimensional ripple patterns can accommodate other unreported modulated phases of ferroelectric topologies, which provide ferroelectric analogs to the complex spin topologies in magnets. The present study not only unveils the intriguing nanoscale electromechanical properties but also opens exciting opportunities to design various functional topological phenomena in flexible materials.

Generalized Lorenz-Mie theory and simulation software for structured light scattering by particles

Structured light refers to an optical field with modulated phase and amplitude, characterized by distinct spatial patterns. It has applications in optical manipulation, 3D imaging, remote sensing, and communications. The Generalized Lorenz-Mie Theory (GLMT) extends foundational Mie theory to accommodate complex structured lights, enabling precise characterization of structured light-particle interactions. GLMT has emerged as a central theoretical framework for analyzing interactions between spherical particles and arbitrary structured light. This paper introduces ABSphere, simulation software utilizing GLMT to model structured light-spherical particle interactions. It then comprehensively reviews representative structured lights, including Laguerre–Gaussian, Bessel, and Airy beams, elucidating their interactions with spherical particles. Understanding structured light scattering behavior is crucial for elucidating underlying interaction mechanisms with spherical particles. The paper also emphasizes the significance of modeling structured light scattering by particles and discusses future directions for ABSphere software. Through continuous theoretical refinements and advancements, deeper understanding of structured light-particle interaction mechanisms can be achieved, enabling innovations in optical applications and technologies.

Grape seed extract prevents chlorpyrifos-induced toxicity in rat liver through the modulation of phase I detoxification pathway.

Chlorpyrifos (CPF) poisoning is a public health problem for which there is not currently any effective prophylaxis. In this study, we investigated the protective effect of grape seed extract (GSE) against CPF-induced hepatotoxicity. Rats were daily treated either with CPF (2mg/kg) or CPF and GSE (20mg/kg) for 1week, sacrificed, and their livers dissected for biochemical, molecular, and histopathological analyses. CPF generated liver dysfunction by altering carbohydrate, lipid, amino acid, ammonia and urea metabolism, and provoked mitochondrial impairment through disturbing tricarboxylic acid (TCA) cycle, oxidative phosphorylation (OXPHOS), and mitochondrial viability. CPF also induced cholinergic excitotoxicity along with oxidative stress and histopathological alterations. Interestingly, treatment with GSE prevented all the detrimental effects of CPF through the regulation of cytochrome P450 (CYP450) gene expression. Molecular docking analysis indicated that GSE-containing polyphenols acted as epigenetic modulators through inhibiting DNA (cytosine-5)-methyltransferase 1 (DNMT1), thus favoring the CYP2C6 detoxification pathway. Thereby, GSE might be a promising strategy in the protection of the liver against CPF toxicity.

Adaptive Phase or Variant Formation at the Austenite/Twinned Martensite Interface in Modulated Ni–Mn–Ga Martensite

AbstractThe crystal structure and transformation path from austenite to 10M martensite in Ni–Mn–Ga single crystal are examined employing high‐energy synchrotron radiation, scanning, and transmission electron microscopy. Using temperature gradient, an austenite/twinned martensite interface is stabilized revealing the crystal structure and microstructure of both phases and the transformation sequence across the interface. Depending on the distance from the interface, three distinct types of martensite crystal lattice, namely simple tetragonal and two monoclinic modulated ones, that is, 10M′ and 10M are confirmed. In situ measurements show that lattice mismatch formed at the habit plane is compensated by the formation of micro‐twinned and branched martensite along with an elastic change in lattice parameters. It is shown that the characteristics for periodic shuffling twin boundaries, such as modulation twins or inverted stacking faults, are installed in later stages of transformation. In other words, large microstructure elements that most efficiently accommodate the strain are installed first, and then smaller elements are operable. Overall, the experimental results show that the crystal lattice does not adapt modulated phase at the habit plane and cannot be built up from simple non‐modulated tetragonal blocks but rather a specific sequence of phase transformations using shear/shuffling deformation takes place.

Metalens in Improving Imaging Quality: Advancements, Challenges, and Prospects for Future Display

AbstractMetalens, a metasurface with a focusing phase, has been the focus of research due to its immense potential for use in imaging and display technology. Traditional lens and optical imaging systems rely on phase accumulation, however metalens with subwavelength structures provide a disruptive path for miniaturized optical imaging systems by allowing unfettered modulation of incident light's phase and amplitude. Recently, extensive efforts have been devoted to exploring new design strategies, new functionalities, and possible applications. This paper reviews the development, principle, classification, and research status of metalens. In particular, this review focuses on the progress and challenges of improving imaging quality and expanding imaging diversity, including improvements of resolution, enhancement of depth of field, extension of field of view, and achromatism. Lastly, the prospects of metalens in the future display are summarized, and the application potentials of metalens in novel 3D display, intelligent and bionic display, as well as nano‐pixelate light‐emitting display (NLED) are emphasized.

Online measurement of birefringence of sensing fibers in the AFOCT system

AbstractThis paper presents a novel scheme to online measure the birefringence of the sensing fiber in all‐fiber optic current transformer (AFOCT) system, which monitors the current on direct current (DC) transmission lines using the Faraday magneto‐optic effect in sensing fibers. In this scheme, by purposefully varying the difference of square‐wave modulated phases via the phase modulator in the AFOCT system, different system transmittances can be obtained. On the basis of the relationship between the system transmittance and linear and circular birefringences, an online measurement scheme of both the linear and circular birefringences of the sensing fibers can be established. In this scheme, the AFOCT system is described by the transmission model based on the Jones matrices, with which the current on DC transmission lines can be measured from the phase shift caused by the Faraday effect. Then, under different square‐wave modulated phases, the system transmittance models are constructed with respect to the linear and circular birefringences of the sensing fiber. For a given sensing fiber with certain linear and circular birefringences, the specific system transmittances are determined and are the curves in space in the respective system transmittance models. Subsequently, these curves in space can be projected onto the coordinate plane composed of the linear and circular birefringence coordinate axes, where the intersection point of the projected plane curves gives the to‐be‐measured values of the linear and circular birefringences of the sensing fiber. The proposed scheme is validated by the preset linear and circular birefringences of the sensing fiber, with different linear birefringences of the polarization‐maintaining fiber. The measurement results show the values consistent with the preset ones.

Environmental Product Declarations as a Data Source for the Assessment of Environmental Impacts during the Use Phase of Photovoltaic Modules: Critical Issues and Potential

In the context of policies promoting renewable energies for decarbonization, energy transition and the development of energy communities, photovoltaic systems require special attention. Even for these systems, it is legitimate to inquire about the correlation, currently carried out through life cycle analysis, between benefits and environmental impacts. To maintain long-term productivity levels and ensure the proper functioning of the system, maintenance interventions are necessary. While these interventions guarantee performance, they also have repercussions for the environment. This study aims to assess the environmental impacts caused by ordinary and extraordinary maintenance interventions, taking into account specific factors, during the 30-year operational phase. To evaluate these impacts, this study verifies the feasibility of using data from Environmental Product Declaration (EPD) and the Product Category Rules (PCR) as reference. The initial results highlight, on the one hand, among the main issues, the importance that all EPDs attribute to the impacts caused by water consumption during the use phase of the PV modules, and on the other hand, some critical issues mainly due to the lack of data relating to the installation site necessary for the correct planning of maintenance activities. Finally, the study presents some reflections for a potential recalibration of the PCR and their associated EPDs.

High-Performance Blue Perovskite Light-Emitting Diodes Enabled by Synergistic Effect of Additives.

While quasi-two-dimensional (quasi-2D) perovskites have good properties of cascade energy transfer, high exciton binding energy, and high quantum efficiency, which will benefit high-efficiency blue PeLEDs, inefficient domain distribution management and unbalanced carrier transport impede device performance improvement. Herein, (2-(9H-carbazol-9-yl)ethyl)phosphonic acid (2PACz) and methyl 2-aminopyridine-4-carboxylate (MAC) were simultaneously introduced to a blue quasi-2D perovskite film. Relying on the synergistic effect of 2PACz and MAC, it not only modulates the phase distribution inhibiting the n = 2 phase but also greatly improves the electrical property of the quasi-2D perovskite film. As a result, the as-modified blue quasi-2D PeLED demonstrated an external quantum efficiency (EQE) of 17.08% and a luminance of 10142 cd m-2. This study exemplifies the synergistic effect among dual additives and offers a new effective additive strategy modulating phase distribution and building balanced carrier transport, which paves the way for the fabrication of highly efficient blue PeLEDs.

Self-Assembled Preparation of Porous Nickel Phosphide Superparticles with Tunable Phase and Porosity for Efficient Hydrogen Evolution.

Self-assembly of colloidal nanoparticles enables the easy building of assembly units into higher-order structures and the bottom-up preparation of functional materials. Nickel phosphides represent an important group of catalysts for hydrogen evolution reaction (HER) from water splitting. In this paper, the preparation of porous nickel phosphide superparticles and their HER efficiencies are reported. Ni and Ni2P nanoparticles are self-assembled into binary superparticles via an oil-in-water emulsion method. After annealing and acid etching, the as-prepared Ni-Ni2P binary superparticles change into porous nickel phosphide superparticles. The porosity and crystalline phase of the superparticles can be tuned by adjusting the ratio of Ni and Ni2P nanoparticles. The resulting porous superparticles are effective in driving HER under acidic conditions, and the modulation of porosity and phase further optimize the electrochemical performance. The prepared Ni3P porous superparticles not only possess a significantly enhanced specific surface area compared to solid Ni-Ni2P superparticles but also exhibit an excellent HER efficiency. The calculations based on the density functional theories show that the (110) crystal facet exhibits a relatively lower Gibbs free energy of hydrogen adsorption. This work provides a self-assembly approach for the construction of porous metal phosphide nanomaterials with tunable crystalline phase and porosity.

Nonlinear edge enhancement imaging based on Laguerre-Gaussian superimposed vortex filters.

Nonlinear reconstruction, which is based on the principle of cross correlation, is a commonly employed reconstruction technique in incoherent correlated digital holography systems. However, the modulation of phase masks in these systems is suppressed during the reconstruction process, resulting in an inability to express the characteristics of the phase masks. Consequently, achieving edge enhancement within these systems is constrained. We propose a nonlinear reconstruction method utilizing Laguerre-Gaussian superimposed vortex filters, which modulates the spectrum of the target during the reconstruction process. Experimental results demonstrate that this method performs well in reconstructing image edges for various phase-masked incoherent imaging systems and effectively suppresses noise. Additionally, this method enables directional edge enhancement.

Tunable and super-wide angle defocusing lens large phase modulator

Traditional terahertz wavefront modulators exhibit significant limitations in controlling optical wavefronts. In order to address the adjustability issues of terahertz wavefront modulators, we have developed a novel optical device based on the tunability of Fermi energy levels. Structurally, we find the ability to modulate the Fermi energy levels of graphene by modulating the carrier concentration. We can also change the phase of the light, causing the transmission path of the light as it passes through the graphene array to change, affecting the position of the backfocusing focal point, thus realizing a dynamically adjustable backfocusing effect. Theoretically, employing Dirac notation and Matrix analyze, reveals the corresponding relationship between Fermi level and phase shift. Specifically, one group Fermi levels induces a set of modulated phase changes. Experimental results demonstrate that the proposed modulator offers a large phase modulation range, enabling 2π phase adjustments. Moreover, it accurately focuses on a predefined focal point located at 400 um, with a numerical aperture of 0.882, a resolution of 30.39, and a full-width at half-maximum of 38. The substantial numerical aperture and small full-width at half-maximum imply that the lens can focus more light while maintaining high resolution, enhanced optical efficiency, and concentrated light focusing. At the same time, by adjusting the position of the Fermi energy level, we have succeeded in realizing a wide-angle focusing effect up to 90°. This capability extends the terahertz wave’s focusing within a wide range, expanding the application scope of traditional focusing devices.

Monolayer Chiral Metasurface for Generation of Arbitrary Cylindrical Vector Beams

The cylindrical vector beam (CVB) has been widely studied and applied in recent years. However, many CVB generation methods suffer from complex systems, and large-size devices are required. Here, we propose a monolayer chiral metasurface composed of spin-sensitive unit cells which can generate different holograms for left- and right-circular polarization based on the combined modulation of geometric phase and detour phase. With a linearly polarized incident beam, the metasurface can generate CVBs with controllable polarization angles and orders, and even more complex vector beams. This work provides a new idea for the design of miniaturized optical devices for generating arbitrary vector beams.

Modulation of the Differential Phase in Atom Gravity Gradiometer via a Bias Magnetic Field

Modulation of the Differential Phase in Atom Gravity Gradiometer via a Bias Magnetic Field

Optically controlled chiral metasurface: Towards controllable bessel beams and holographic logic operation

Chiral metasurfaces have expanded the control dimensions of traditional two-dimensional materials for manipulating beams, allowing for joint modulation of amplitude, phase, and polarization. As a result, they have attracted significant attention. This paper focuses on the tunable chiral metasurface applied in the THz regime. We propose an Ω-shaped metallic structure with an embedded photosensitive semiconductor material that allows for differential absorption of THz incident waves with various spins. The circular dichroic response of the designed chiral unit can be tuned by controlling the frequency and intensity of the pump light. The introduction of the PB (Pancharatnam-Berry) phase grants the chiral unit the ability to control the phase. In conclusion, the chiral unit achieves perfect control over the amplitude and phase of co-polarized reflected beams in the 7THz-9.7THz frequency range. In this paper, the aforementioned metasurface units are arranged into an array to achieve intensity-controllable Bessel beam and holographic logic operation. This proves the excellent performance of the designed chiral units in the THz regime. The optically controlled chiral metasurface proposed in this paper not only has application value in molecular control and optical computing but also provides a new approach for the THz chiral metasurface design.

Generation of high radial node vector vortex beams based on digital micromirror device

The modulation of amplitude, phase, and polarization to generate complex vector light fields with spatially variant polarization distribution has become a hot research topic in recent years. We propose a new method for generating high radial node vector vortex beams (VVB) based on a digital micromirror device (DMD). Firstly, we propose a multiplexed binary hologram with varying ellipticity, which can significantly optimize the vortex beam generated by DMD while the mode purity of the scalar vortex beam after optimization can reach 97.23%. Secondly, a novel interference experimental setup is proposed based on the Wollaston prism, which can realize arbitrary control of VVBs. Based on this, the high radial node VVBs with p=10 and high polarization order VVBs with polarization order up to 25 are generated experimentally. Finally, we reconstruct the State of Polarization (SoP) of the vector beam l=4,m=-4,p=4 based on the Stokes parameter S1,S2,S3, and the variation of vector quality factor (VQF) on the high-order Poincaré sphere (HOPS) is analyzed. Our technology provides a high-quality vector beam generation scheme with important applications in laser detection, optical communication, and optical micro-manipulation.

Glycan-Driven Formation of Raft-Like Domains with Hierarchical Periodic Nanoarrays on Dendrimersome Synthetic Cells.

The accurate spatial segregation into distinct phases within cell membranes coordinates vital biochemical processes and functionalities in living organisms. One of nature's strategies to localize reactivity is the formation of dynamic raft domains. Most raft models rely on liquid-ordered L0 phases in a liquid-disordered Ld phase lacking correlation and remaining static, often necessitating external agents for phase separation. Here, we introduce a synthetic system of bicomponent glycodendrimersomes coassembled from Janus dendrimers and Janus glycodendrimers (JGDs), where lactose-lactose interactions exclusively drive lateral organization. This mechanism results in modulated phases across two length scales, yielding raft-like microdomains featuring nanoarrays at the nanoscale. By varying the density of lactose and molecular architecture of JGDs, the nanoarray type and size, shape, and spacing of the domains were controlled. Our findings offer insight into the potential primordial origins of rudimentary raft domains and highlight the crucial role of glycans within the glycocalyx.

Study of the Blazhko Type RRc stars in the Stripe 82 Region Using SDSS and ZTF

RR Lyrae stars (RRLs) are pulsating stars, many of which also show a long-term variation called the Blazhko effect which is a modulation of amplitude and phase of the lightcurve. In this work, we searched for the incidence rate of the Blazhko effect in the first-overtone pulsating RR Lyrae (RRc) stars of the Galactic halo. The focus was on the Stripe 82 region in the Galactic halo which was studied by Sesar et al. using the Sloan Digital Sky Survey (SDSS) data. In their work, 104 RRLs were classified as RRc type. We combined their SDSS light curves with Zwicky Transient Facility (ZTF) data, and used them to document the Blazhko properties of these RRc stars. Our analysis showed that among the 104 RRc stars, eight were rather RRd stars, and were excluded from the study. Out of the remaining 96, 34 were Blazhko type, 62 were non-Blazhko type, giving the incidence rate of 35.42% for Blazhko RRc stars. The shortest Blazhko period found was 12.808 ± 0.001 days for SDSS 747380, while the longest was 3088 ± 126 days for SDSS 3585856. Combining SDSS and ZTF data sets increased the probability of detecting the small variations due to the Blazhko effect, and thus provided a unique opportunity to find longer Blazhko periods. We found that 85% of RRc stars had the Blazhko period longer than 200 days.