Phase Shift Parameter Research Articles

Morphological and Optical Profiling of Melanocytes and SK-MEL-28 Melanoma Cells Via Digital Holographic Microscopy and Quantitative Phase Imaging.

Melanoma, which originates from pigment-producing melanocytes, is an aggressive and deadly skin cancer. Despite extensive research, its mechanisms of progression and metastasis remain unclear. This study uses quantitative phase imaging via digital holographic microscopy, Principal Component Analysis (PCA), and t-distributed Stochastic Neighbor Embedding (t-SNE) to identify the morphological, optical, and behavioral differences between normal melanocytes and SK-MEL-28 melanoma cells. Our findings reveal significant differences in cell shape, size, and internal organization, with SK-MEL-28 cells displaying greater size variability, more polygonal shapes, and higher optical thickness. Phase shift parameters and surface roughness analyses underscore melanoma cells' uniform and predictable textures. Violin plots highlight the dynamic and varied migration of SK-MEL-28 cells, contrasting with the localized movement of melanocytes. Hierarchical clustering of correlation matrices provides further insights into complex morphological and optical relationships. Integrating label-free imaging with robust analytical methods enhances understanding of melanoma's aggressive behavior, supporting targeted therapies and highlighting potential biomarkers for precise melanoma diagnostics and treatment.

Quantum-optimal information encoding using noisy passive linear optics

The amount of information that a noisy channel can transmit has been one of the primary subjects of interest in information theory. In this work we consider a practically-motivated family of optical quantum channels that can be implemented without an external energy source. We optimize the Holevo information over procedures that encode information in attenuations and phase-shifts applied by these channels on a resource state of finite energy. It is shown that for any given input state and environment temperature, the maximum Holevo information can be achieved by an encoding procedure that uniformly distributes the channel's phase-shift parameter. Moreover for large families of input states, any maximizing encoding scheme has a finite number of channel attenuation values, simplifying the codewords to a finite number of rings around the origin in the output phase space. The above results and numerical evidence suggests that this property holds for all resource states. Our results are directly applicable to the quantum reading of an optical memory in the presence of environmental thermal noise.

Theory and Design of High-Efficiency Broadband Class-B/J Power Amplifiers With Active Second Harmonic Injection

In this article, the theory and design of high-efficiency broadband continuous class-B/J power amplifiers (PAs) with active second harmonic injection technique have been presented. By injecting the second harmonic component generated by the auxiliary PA, the optimal phase shift parameter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\alpha $</tex-math> </inline-formula> between the drain voltage and current can be selected properly, leading to an efficiency and power improvement of the conventional class-B/J PA. Detailed design guidelines and step-by-step procedure are also suggested. To verify the feasibility of the proposed circuit, a wideband PA operated from 1.1 to 1.7 GHz (fractional bandwidth of 42.9%) has been designed and fabricated. Experimental results show an output power of 40.9–42.6 dBm, drain efficiency of 70.0%–80.9%, and average efficiency (AE) of 74.4%. To the best of our knowledge, this is the highest AE of class-B/J PAs over such bandwidth.

Improved Triple-Phase-Shift Modulation for Bidirectional CLLC Converters

CLLC resonant converters are an attractive option for battery charging applications due to their bidirectional power flow and high efficiency. Pulse frequency modulation (PFM) is the simple method to drive CLLC converters. However, PFM cannot regulate the output voltage under the light-load condition properly, which leads to high switching and core losses. Phase shift modulation techniques like dual-phase shift (DPS) modulation can overcome this challenge. However, more improvements are demanded due to high circulating currents in phase shift modulations. In this paper, an improved modulation technique based on triple-phase shift (TPS) has been applied in CLLC converters to improve the light-load efficiency. TPS modulation like any other phase-shift modulation, keeps the switching frequency of CLLC converters fixed at the resonant frequency under the light-load condition and regulates the output voltage by its three phase shift parameters. The improved TPS modulation has lower circulating current at the same average output current compared to DPS modulation. Therefore, higher efficiency, smaller peak, and RMS current values can be achieved under the light-load condition. In addition, the proposed TPS modulation has a better flexibility in regulating the output voltage under the light-load condition due to an extra phase shift parameter compared to DPS modulation. The proposed TPS modulation has been analyzed thoroughly in this paper and a proper selection of phase shift values has been explained to improve the efficiency of the converter. Finally, advantages of the improved TPS modulation have been validated by simulation and a 1 kW experimental setup.

The influence of boundary scattering phase shift on melting behavior of nanoparticles

Based on the Lindemann melting criterion and the lattice dynamical approach, we analytically estimated the melting temperature of nanoparticles with emphasis on the influence of the boundary scattering phase shift parameter α . With the decrease of size, the estimated relation shows that the melting temperature of free standing like nanoparticles will decrease, and the melting temperature of embedded nanoparticles will increase. The increase or decrease of the melting temperature depends on the boundary scattering phase shift parameter. The gradual change of parameter α from − 1 to 1 corresponds to the transition of the surface or environment of nanoparticles from the free boundary condition to the fixed boundary condition. Our analytical estimation qualitatively explains the experimental data, and its predictive capability will help the design of nanoparticles. • Based on the Lindemann criterion, An analytical estimation for size-dependent melting temperature of nanoparticles by lattice dynamical method will be given. • Our theoretical result can fit experimental data of nanoparticles in different environments qualitatively. • A simple boundary scattering phase shift is used to characterize the environment of nanoparticles.

Secure computation offloading assisted by intelligent reflection surface for mobile edge computing network

As an novel paradigm, computation offloading in the mobile edge computing (MEC) system can effectively support the resource-intensive applications for the mobile devices (MD) equipped with limited computing capability. However, the hostile radio transmission and data leakage during the offloading process may erode the MEC system’s potential. To tackle these hindrances, we investigate an IRS-assisted secure MEC system with eavesdroppers, where the intelligent reflecting surface (IRS) is deployed to enhance the communication between the MD and the AP equipped with edge servers and the malicious eavesdroppers may attack the wireless data offloaded by MD. The MD opt for offloading part of the tasks to the edge server for execution to support the computation-intensive applications. Moreover, the relevant latency minimization problem is formulated by optimizing the offloading ratio, the allocation of edge server computing capability, the multiple-user-detection (MUD) matrix and the IRS phase shift parameters, subject to the constraints of edge computation resource and practical IRS phase shifts. Then, the original problem is decouple into two subproblem, and the computing and communication subproblems are alternatively optimized by block coordinate descent (BCD) method with low complexity. Finally, simulation results demonstrate that the proposed scheme can significantly enhance the performance of secure offloading in the MEC system.

Constraining the particle-scale diversity of black carbon light absorption using a unified framework

Abstract. Atmospheric black carbon (BC), the strongest absorber of visible solar radiation in the atmosphere, manifests across a wide spectrum of morphologies and compositional heterogeneity. Phenomenologically, the distribution of BC among diverse particles of varied composition gives rise to enhancement of its light absorption capabilities by over twofold in comparison to that of nascent or unmixed homogeneous BC. This situation has challenged the modeling community to consider the full complexity and diversity of BC on a per-particle basis for accurate estimation of its light absorption. The conventionally adopted core–shell approximation, although computationally inexpensive, is inadequate not only in estimating but also capturing absorption trends for ambient BC. Here we develop a unified framework that encompasses the complex diversity in BC morphology and composition using a single metric, the phase shift parameter (ρBC), which quantifies how much phase shift the incoming light waves encounter across a particle compared to that in its absence. We systematically investigate variations in ρBC across the multi-space distribution of BC morphology, mixing state, mass, and composition as reported by field and laboratory observations. We find that ρBC&gt;1 leads to decreased absorption by BC, which explains the weaker absorption enhancements observed in certain regional BC compared to laboratory results of similar mixing state. We formulate universal scaling laws centered on ρBC and provide physics-based insights regarding core–shell approximation overestimating BC light absorption. We conclude by packaging our framework in an open-source Python application to facilitate community-level use in future BC-related research. The package has two main functionalities. The first functionality is for forward problems, wherein experimentally measured BC mixing state and assumed BC morphology are input, and the aerosol absorption properties are output. The second functionality is for inverse problems, wherein experimentally measured BC mixing state and absorption are input, and the morphology of BC is returned. Further, if absorption is measured at multiple wavelengths, the package facilitates the estimation of the imaginary refractive index of coating materials by combining the forward and inverse procedures. Our framework thus provides a computationally inexpensive source for calculation of absorption by BC and can be used to constrain light absorption throughout the atmospheric lifetime of BC.

Adaptive Confidence Verification for Analysis of BPSK Signals

The existing extreme statistic-based confidence test approaches for the analysis results of binary phase-shift keying (BPSK) signals, i.e., modulation recognition and parameter estimation, do not perform well under transmission impairments, partly due to their insufficient use of extreme samples. This article proposes a copula-based algorithm for the confidence test of BPSK signal analysis by combining the block maxima-based and peak-over-the-threshold-based extreme statistics. The test statistic is developed relying on the one-class detector using the copula probability density function under the null hypothesis, and the threshold is obtained adaptively through the bootstrap algorithm. The proposed statistic is proved to be asymptotically Gaussian distributed. By comparing the statistic with such a threshold, the confidence test is performed. Extensive simulations validate the effectiveness of the proposed algorithm.

A framework for optimal quantum spatial search using alternating phase-walks

We present a novel methodological framework for quantum spatial search, generalising the Childs & Goldstone () algorithm via alternating applications of marked-vertex phase shifts and continuous-time quantum walks. We determine closed form expressions for the optimal walk time and phase shift parameters for periodic graphs. These parameters are chosen to rotate the system about subsets of the graph Laplacian eigenstates, amplifying the probability of measuring the marked vertex. The state evolution is asymptotically optimal for any class of periodic graphs having a fixed number of unique eigenvalues. We demonstrate the effectiveness of the algorithm by applying it to obtain search on a variety of graphs. One important class is the n × n 3 rook graph, which has N = n 4 vertices. On this class of graphs the algorithm performs suboptimally, achieving only overlap after time . Using the new alternating phase-walk framework, we show that overlap is obtained in phase-walk iterations.

Waves in the cochlea and in acoustic rainbow sensors

A WKB solution to the cochlear wave equation is derived, which results from the interaction between the passive dynamics of the basilar membrane and the 1D fluid coupling in the scalae, including both fluid viscosity and compressibility. The effect of various nondimensional parameters on the form of this solution is discussed. A nondimensional damping parameter and a nondimensional phase-shift parameter are shown to have the greatest influence on the response under normal conditions in the cochlea, with the fluid viscosity and compressibility only playing a minor role. It is then shown that in the case of an acoustic rainbow sensor, comprised of a discrete series of Helmholtz resonators in a duct, the governing wave equation in the continuous limit has the same form as the cochlear wave equation. The nondimensional compressibility parameter in this case is governed by the ratio of the Helmholtz resonator volume to that of the connecting duct and this parameter can be much larger than in the cochlea, and so plays a more dominant role in determining the response.

Power optimization for target localization with reconfigurable intelligent surfaces

Target localization plays an indispensable role in wireless network and array signal processing. Generally, the traditional methods are restricted to the line of sight (LOS) transmission link assumption, and may fail in the non line of sight (NLOS) scenario. As a promising technology, reconfigurable intelligent surface (RIS) can customize the wireless channel and then overcome the performance degradation due to the lack of LOS. In this paper, we consider the power optimization problem of RIS localization, which is crucial for localization accuracy and energy consumption. In order to minimize the transmit power, we investigate several power optimization problems of the RIS localization under the constraints of the localization accuracy and the phase shift parameters of the RIS. Specifically, aiming at the RIS system with an anchor node (AN) and an target node (TN), we derive the Cramér-Rao bound (CRB) in terms of the location parameters of the TN, and prove the theoretic result of the relation between the optimal power and the phase parameters of the RIS. Based on these results, we formulate the corresponding power optimization problem, and derive the analytical solution of the optimization problem. Next, we obtain the convex form of the power optimization problem for the second scenario, that is, the RIS system with multiple TNs and single AN. Lastly, for the multiple ANs scenario with single TN, we solve the power optimization problem by using semidefinite release (SDR) method. Simulation results verify the feasibility of the proposed methods.

A Broadband High-Efficiency Hybrid Continuous Inverse Power Amplifier Based on Extended Admittance Space

A novel hybrid continuous inverse power amplifier (PA) that is constituted by a continuum of PA modes from the continuous inverse class-F to the continuous inverse class-B/J is proposed, and a detailed mathematical analysis is presented. The fundamental and second harmonic admittance spaces of the hybrid PA proposed in this article are analyzed mathematically. By introducing the phase shift parameter into the current waveform formula of the hybrid continuous inverse PA, the design space of the fundamental and second harmonic admittance is expanded, further increasing the operating bandwidth. The efficiency of the amplifier under different parameter conditions is calculated. In order to verify this method, a broadband high-efficiency PA is designed and fabricated. The drain voltage and current waveforms of the amplifier are extracted for analysis. The experimental measured results show a 60.7–71.5% drain efficiency across the frequency band of 0.5–2.5 GHz (133% bandwidth), and the designed PA can obtain an 11.8–13.9 dB gain in the interesting frequency range. The measured results are confirmed to be in good agreement with theory and simulations.

Supersensitivity of Patients With Bipolar I Disorder to Light-Induced Phase Delay by Narrow Bandwidth Blue Light

BackgroundBipolar disorder is a severe chronic mental disorder. There is a bidirectional relationship between disease course and circadian phase. Significant circadian phase shifts occur during transitions between episodes, but episodes can also be elicited during euthymia by forced rapid changes in circadian phase. Although an instability of circadian phase has been described in multiple observational reports, no studies quantifying the propensity to phase shift following an experimental standardized stimulus have been published. This study therefore aimed to assess whether patients with bipolar I disorder (BDI) are more prone to phase delay following blue light exposure in the evening than healthy control subjects. MethodsEuthymic participants with BDI confirmed by Structured Clinical Interview for DSM-IV Axis I (n = 32) and healthy control subjects (n = 55) underwent a 3-day phase shift protocol involving exposure to a standardized dose of homogeneous, constant, narrow bandwidth blue light (478 nm, half bandwidth = 18 nm, photon flux = 1.29 × 1015 photons/cm2/s) for 2 hours at 9:00 pm via a ganzfeld dome on day 2. On days 1 and 3, serial serum melatonin assessments during total darkness were performed to determine the dim light melatonin onset. ResultsSignificant differences in the light-induced phase shift between BDI and healthy control subjects were detected (F1,82 = 4.110; p = .046), with patients with bipolar disorder exhibiting an enhanced phase delay (η2 = 0.49). There were no significant associations between the magnitude of the phase shift and clinical parameters. ConclusionsSupersensitivity of patients with BDI to light-induced phase delay may contribute to the observed phase instability and vulnerability to forced phase shifts associated with the disorder.

Research on phase shift characteristics of electromagnetic wave in plasma

The phase shift characteristics reflect the state change of electromagnetic wave in plasma sheath and can be used to reveal deeply the action mechanism between electromagnetic wave and plasma sheath. In this paper, the phase shift characteristics of electromagnetic wave propagation in plasma were investigated. Firstly, the impact factors of phase shift including electron density, collision frequency and incident frequency were discussed. Then, the plasma with different electron density distribution profiles were employed to investigate the influence on the phase shift characteristics. In a real case, the plasma sheath around the hypersonic vehicle will affect and even break down the communication. Based on the hypersonic vehicle model, we studied the electromagnetic wave phase shift under different flight altitude, speed, and attack angle. The results indicate that the phase shift is inversely proportional to the flight altitude and positively proportional to the flight speed and attack angle. Our work provides a theoretical guidance for the further research of phase shift characteristics and parameters inversion in plasma.

Estimation of Ferroelectric Material Properties and Phase-Shifter Design Key Parameters Influence on Its Figure of Merit for Optimization of Development Process

A model of the estimation of the ferroelectric-based phase-shifter figure of merit concerning the material properties and phase-shifter design parameters is presented. The influence of ferroelectric material tunability and losses on phase-shifter characteristics are analyzed. Two approaches to phase-shifter design (transmission line and band-pass filter) are considered. The review of the published results on the ferroelectric phase-shifter design was performed to approve the method proposed. Recommendations to optimize the phase-shifter development process are suggested on the basis of the elaborated model and analysis performed.

Verification of Phase Shifter Measurements of a Reflective Array Antenna

Introduction. Large-size phased antenna arrays (PAA) frequently incorporate optical excitation schemes, whose main elements include the feed and the reflective aperture. In turn, the reflective aperture consists of several tens of thousands of radiators and phase shifters. Major distortions of the radiation pattern in reflective arrays occur due to phase errors, leading to a decrease in the gain and an increase in the side lobes of the radiation pattern. In the millimeter wavelength range, ferrite phase shifters can have an initial phase from 0 to 360 °, thus requiring measurements of the array elements following their assembly.Aim. To develop a method for evaluating errors in measurements of the parameters of phase shifters incorporated in an antenna array by comparing theoretical and experimental data.Materials and methods. A convenient method for determining the parameters of phase shifters is probing, in which a movable probe is connected in series with each array element. In cases where a PAA element represents a single structure consisting of a ferrite segment and a dielectric radiator, measurements are carried out using a probe in the form of a segment of a round waveguide moving towards the radiator. In order to evaluate the measurement error of such a scheme, a mechanically controlled reference phase shifter was used.Results. Measurement errors for the probe structure used were calculated based on the assumption of the phase error arising from the vector addition of the controlled and uncontrolled reflected signals at the input of the PAA element, in the section of the reference plane at the input of the probe. In addition, the S-parameters of the superposition section were calculated. The extrema of the error function were used to determine the maximum errors in measuring the phase and amplitude.Conclusion. The performed analysis confirmed the validity of the proposed method for measuring the parameters of phase shifters using a waveguide probe. The measurement error of the PAA elements according to the proposed scheme was found to be about 3 o, which is commensurate with that of recording devices.

Distribution Network Hierarchically Partitioned Optimization Considering Electric Vehicle Orderly Charging with Isolated Bidirectional DC-DC Converter Optimal Efficiency Model

The access of large-scale electric vehicles (EVs) will increase the network loss of medium voltage distribution network, which can be alleviated by adjusting the network structure and orderly charging for EVs. However, it is difficult to accurately evaluate the charging efficiency in the orderly charging of electric vehicle (EV), which will cause the scheduling model to be insufficiently accurate. Therefore, this paper proposes an EV double-layer scheduling model based on the isolated bidirectional DC–DC (IBDC) converter optimal efficiency model, and establishes the hierarchical and partitioned optimization model with feeder–branch–load layer. Firstly, based on the actual topology of medium voltage distribution network, a dynamic reconfiguration model between switching stations is established with the goal of load balancing. Secondly, with the goal of minimizing the branch layer network loss, a dynamic reconstruction model under the switch station is established, and the chaotic niche particle swarm optimization is proposed to improve the global search capability and iteration speed. Finally, the power transmission loss model of IBDC converter is established, and the optimal phase shift parameter is determined to formulate the double-layer collaborative optimization operation strategy of electric vehicles. The example verifies that the above model can improve the system load balancing degree and reduce the operation loss of medium voltage distribution network.

Solitons in [formula omitted] symmetric Manakov system

Parity-time (PT)-symmetric Manakov system including four cases are discussed in this paper, which is used to depict the nonlinear waves in optical fibers. Via constructing the generalized Manakov system, soliton/soliton-like solutions of PT-symmetric Manakov system are attained: First and second cases are the solitons and periodic solutions, respectively; Third and fourth cases are the soliton-like solutions. Loss and gain of the soliton-like propagation is not balanced in the third and fourth cases, which is consistent with the experimental result. Time frequency-spectrum of the fourth case are analyzed: Phase spectrum of the one-order soliton-like and amplitude spectrum of the two-order soliton-like both have periodic perturbation. Besides, bilinear forms of the M(M>2)-coupled PT-symmetric Manakov system are also attained, which can help us to obtain the M-dimension vector solitons and discuss the nonlinear waves in multi-mode optical fibers. At the end of this paper, we display the rogue waves of generalized Manakov system and discuss the relations between the linear turbulence and rogue-wave's shape. Amplitude of the rogue wave is increased with a phase-shift parameter (δ1). Time frequency-spectrum of the rogue wave are analyzed.

Achievable Rate Optimization for Aerial Intelligent Reflecting Surface-Aided Cell-Free Massive MIMO System

The intelligent reflecting surface (IRS) is considered a core technology of next-generation mobile communication. It has significant advantages in enhancing network coverage, spectrum efficiency, energy efficiency, and deployment cost. Compared with the conventional massive multiple-input-multiple-output (MIMO) system, cell-free massive MIMO overcomes the limitation imposed by inter-cell interference in traditional cellular mobile networks and realizes coherent transmission centered on users. In this article, we consider a new application scenario for the IRS — an aerial IRS (AIRS)-aided cell-free massive MIMO system where multiple APs serve several users through an AIRS. The users are in a “shadow area” where we cannot provide good quality of service (QoS) due to the remote location and the shelter of tall buildings. Our goal is to optimize the power allocation and beamforming of each AP, the placement and reflection phase shift parameters of the AIRS to maximize the user’s achievable rate. Firstly, we consider the optimization for fixed placement of the AIRS, where we propose a joint optimization strategy to maximize the achievable rate of the user. Then, we propose a fast optimal location search algorithm base on the path loss model to determine the optimal location of the AIRS and decrease the computational complexity. The simulation results show that the proposed methods can improve the performance for the achievable rate of the system. To the best of our knowledge, this article is the first to study the application scenario for the combination of IRS technology and a cell-free massive MIMO system.

Spectral approach to recognize spherical particles among non-spherical ones by angle-resolved light scattering

Most of known light-scattering technologies, which allow one to separate spherical from non-spherical single particles, utilize either analysis of 2D light-scattering pattern or depolarization of light scattered. Both approaches force one to use high-sensitive detectors to provide a suitable signal to noise ratio for two-dimensionless photo matrix or for optical system with crossed polarizers. In this study, we introduce the method for discrimination of spherical and non-spherical single particles. The approach is based on measurement of leading, most intensive, element S11 of light-scattering matrix. To provide maximal signal to noise ratio we specified the light-scattering profile (LSP) in terms of integrated over azimuthal angle S11 as a function of polar scattering angle. The shape-sensitive vector-invariant for individual spherical particles was constructed from the parameters of LSP spectrum. The vector-invariant plays a role of the numerical criterion to identify spherical particles from LSPs. It can be applied to find a sphere with characteristics ranging from 16.5 to 70 and from 0.5 to 7.0 for size and phase-shift parameters respectively (size parameter α = πdn0/λ, where d – sphere diameter, λ – wavelength of the incident light, and n0 – medium refractive index, RI, phase-shift parameter ρ = 2α(m − 1), where relative RI m = n/n0 and n is the sphere RI). These ranges cover all possible characteristics of blood cells within the visible region of wavelengths. The ability of the vector-invariant to recognize spherical cells among non-spherical ones was tested theoretically by LSP databases of optical models of platelets and mature red blood cells. Moreover, experimentally the vector-invariant demonstrated good performance in searching of near-perfect spheres among milk fat globules, isolated nuclei of mononuclear cells, and completely spherized cells in a course of red blood cell lysis.