Relative Phase Research Articles

Multi-phase transition behavior over a wide temperature range in magnetocaloric (Mn, Fe, Ni)2(P, Si) alloys

This study investigates the magnetocaloric property of MnFe0.95-xNixP0.6Si0.4 (x = 0.02, 0.03, 0.04) alloys over a wide temperature range and their related phase transitions. These P-rich composition alloys, with a P/Si ratio of 1.5, exhibit multi-phase transition behavior across a broad temperature range. In-situ 2D X-ray diffraction reveals overlapping diffraction peaks of the Fe2P-type hexagonal structure throughout the ferromagnetic-paramagnetic transition, rather than a single, drastic transition. This observation suggests the formation of a multi-phase structure within the alloys. Consequently, these alloys exhibit high refrigeration capacity (RC) values ranging from 168.6 to 218.1 J kg−1 under an applied magnetic field of 2 T. Notably, these RC values are superior to those observed in other P/Si ratio compositions without multi-phase transitions or even Gd, a representative magnetocaloric material. This improved performance demonstrates the promising potential of these multi-phase transition alloys as candidates for magnetocaloric refrigeration systems.

Data-driven predictive maintenance framework considering the multi-source information fusion and uncertainty in remaining useful life prediction

The existing equipment maintenance methods mainly separate the two related phases of prediction and predictive maintenance (PdM) by looking at remaining useful life (RUL) prediction without considering maintenance or optimizing maintenance schedules based on the given prediction information. To address this issue, we propose a framework based on a multi-stream attention fusion network with quantile regression model and deep reinforcement learning (DRL). In this novel framework, the multi-stream attention fusion block is used to comprehensively capture the operating status of industrial equipment and eliminate the extracted duplicate information. Quantile regression is employed to obtain the probabilistic RUL prediction results with uncertainty expression. We further formulate the PdM problem for DRL, where maintenance actions are triggered based on the estimates of the RUL distribution. To illustrate the superiority of our framework, we compare it with some state-of-the-art models using a public data and our private data. The experimental results indicate that our method exhibits high accuracy and stability in bearing RUL prediction and predictive replacement.

Generative adversarial networks with deep blind degradation powered terahertz ptychography

Ptychography is an imaging technique that uses the redundancy of information generated by the overlapping of adjacent light regions to calculate the relative phase of adjacent regions and reconstruct the image. In the terahertz domain, in order to make the ptychography technology better serve engineering applications, we propose a set of deep learning terahertz ptychography system that is easier to realize in engineering and plays an outstanding role. To address this issue, we propose to use a powerful deep blind degradation model which uses isotropic and anisotropic Gaussian kernels for random blurring, chooses the downsampling modes from nearest interpolation, bilinear interpolation, bicubic interpolation and down-up-sampling method, and introduces Gaussian noise, JPEG compression noise, and processed detector noise. Additionally, a random shuffle strategy is used to further expand the degradation space of the image. Using paired low/high resolution images generated by the deep blind degradation model, we trained a multi-layer residual network with residual scaling parameters and dense connection structure to achieve the neural network super-resolution of terahertz ptychography for the first time. We use two representative neural networks, SwinIR and RealESRGAN, to compare with our model. Experimental result shows that the proposed method achieved better accuracy and visual improvement than other terahertz ptychographic image super-resolution algorithms. Further quantitative calculation proved that our method has significant advantages in terahertz ptychographic image super-resolution, achieving a resolution of 33.09 dB on the peak signal-to-noise ratio (PSNR) index and 3.05 on the naturalness image quality estimator (NIQE) index. This efficient and engineered approach fills the gap in the improvement of terahertz ptychography by using neural networks.

Deciphering the role of three-color synthesized laser pulse parameters in N2 ionization and attosecond pulse shaping

Photoionization of atoms or molecules is a fundamental process in strong-field physics, essential for generating high-order harmonics and producing attosecond pulses. Here, we investigate how a three-color laser field, consisting of wavelengths at 800 nm and its second and third harmonics, photoionizes N2 molecules and evaluates its effect on the properties of attosecond pulses. It has been discovered that by altering the relative phase, these harmonics periodically influence molecular ionization, increasing the discreteness and strength of the attosecond pulse trains. Three-color field driving dramatically raises the pulse peak while decreasing the width of the strongest peak pulse, whereas two-color field driving just slightly enhances the pulse intensity and duration. Furthermore, the effectiveness of harmonic production is significantly increased by varying the laser intensity ratios. Even though the efficiency and pulse intensity of the three-color field are limited by conversion efficiency, attosecond pulses with higher intensities can be produced with proper parameter tuning at lower ionization rates. These findings offer a significant foundation for precisely controlling attosecond pulse generation. Ocis codes320.7110; 320.7120.

Formation mechanisms of dynamic capabilities based on relational capital of enterprises in emerging economies under institutional change: a multiple case study in the context of China’s reform and opening-up

ABSTRACT This study analyzes how Chinese enterprises build and enhance dynamic capabilities during the reform and opening-up period, illustrating the transition from reliance on personal and political relationships in the startup phase to dependence on technology and global market information in the maturity phase. The research indicates that changes in the policy environment are key drivers for the formation of dynamic capabilities. Enterprises must continuously adjust their strategies and relational capital to swiftly adapt to policy changes and maintain competitiveness. This study not only deepens the understanding of the process-oriented theory of dynamic capabilities but also offers new perspectives on the strategic behavior of enterprises in emerging markets, particularly regarding how the dynamics of the institutional environment influence the formation and utilization of dynamic capabilities. The research emphasizes the strategic importance of relational capital and explores how enterprises continuously adjust relational capital to build and enhance dynamic capabilities. The findings provide concrete operational strategies and deep insights for enterprise managers and policymakers, helping them more effectively grasp the key factors of enterprise growth and environmental adaptation.

Dance of two brains: Interval subdivision in alternated condition enhances resistance to interference by others

The accomplishment of interpersonal sensorimotor synchronization is a challenging endeavor because it requires the achievement of a balance between accurate temporal control within individuals and smooth communication between them. This raises a critical question: How does the brain comprehend and process the perceptual information of others to guarantee accurate temporal control of action goals in a social context? A joint synchronization - continuation tapping task was conducted together with varying relative phases (0°/180°) and intervals of tempos (400 ms/800 ms/1600 ms) while neural data was collected using fNIRS (functional near-infrared spectroscopy). Individuals showed better behavioral performance and greater interpersonal brain synchronization(IBS) in the left dorsolateral prefrontal cortex at alternated condition (180° relative phase) compared to symmetric condition (0° relative phase), suggesting that the individual can better maintain behavioral performance and show improved IBS when the partner taps between the individual's gaps. Meanwhile, in most levels of alternated condition, IBS is inversely proportional to interference from partner, implying the counteraction of IBS against interference from others. In addition, when the interval of tempo was 1600 ms, behavioral performance showed a sharp decline, accompanied by a decrease in IBS, reflecting that IBS in SMS reflects effective information exchange between individuals rather than ineffective interference with each other. This study provides insight into the mechanisms underlying sensorimotor synchronization between individuals.

Loss-induced quantum nonreciprocity

Attribute to their robustness against loss and external noise, nonreciprocal photonic devices hold great promise for applications in quantum information processing. Recent advancements have demonstrated that nonreciprocal optical transmission in linear systems can be achieved through the strategic introduction of loss. However, a crucial question remains unanswered: can loss be harnessed as a resource for generating nonreciprocal quantum correlations? Here, we take a counterintuitive stance by engineering loss to generate a vital form of nonreciprocal quantum correlations, termed nonreciprocal photon blockade. We examine a dissipative three-cavity system comprising two nonlinear cavities and a linear cavity. The interplay of loss and nonlinearity leads to a robust nonreciprocal single- and two-photon blockade, facilitated by destructive quantum interference. Furthermore, we demonstrate the tunability of this nonreciprocal photon blockade by manipulating the relative phase between the two nonlinear cavities. Remarkably, this allows for the reversal of the direction of nonreciprocity. Our study not only sheds a light on the concept of loss-engineered quantum nonreciprocity but also opens up a pathway for the design of quantum nonreciprocal photonic devices.

(Invited) Towards an Expanded Palette of Materials and Mechanisms for Neuromorphic Computing

The metal-insulator transitions of electron correlated transition metal oxides provide an attractive vector for achieving large conductance switching with minimal energy dissipation. However, given the sparse and disconnected current knowledge of neuromorphic materials, a fundamental understanding of descriptors of neuromorphic function formulated in terms of intrinsic material properties, and the influence of atomistic defects on mesoscale domain evolution in the presence of external applied fields is currently lacking. Using VO2 and M x V2O5 compounds as model systems, I will detail our efforts to develop a systematic understanding of how compositional modifications through substitutional or interstitial doping alter transformation characteristics such as the transition temperature, magnitude of switching, energy dissipation, and hysteresis.The inclusion of dopant atoms strongly modifies the free energy landscapes in terms of relative phase stabilities, transformation barriers, and pathways; thereby profoundly altering the coupling of lattice, electronic, and spin degrees of freedom in a non-trivial manner. I will particularly focus on the three distinct mechanisms: (a) discovery of diffusive dopants that provide a distinctive new way to alter the dynamics of electronic transitions; (b) cation shuttling and polaron oscillation as a means of engendering metal—insulator transitions; and (c) lattice-anharmonicity-driven mechanisms in compounds with stereochemically active lone pairs. Acknowledgements: Research supported as part of REMIND, an Energy Frontier Research Center funded by the U.S. Department of Energy (DOE), Office of Science, Basic Energy Sciences (BES), under DE-SC0023353

Efficient Control of Electron Localization and Probability Modulation with Synthesized Two-Color Intense Laser Pulses.

A coupled electron-nuclear dynamical study at attosecond time scale is performed on the HD+ and H2+ molecular ions under the influence of synthesized intense two-color electric fields. We have employed ω - 2ω and also, ω - 3ω two-color fields in the infrared/mid-infrared regime to study the different fragmentation processes originating from the interference of n - (n + i) (i = 1, 2) photon absorption pathways. The branching ratios corresponding to different photofragments are controlled by tuning the relative phase as well as intensity of the two-color pulses, while the effect of the initial nuclear wave function is also studied by taking an individual vibrational eigenstate or a coherent superposition of several eigenstates of HD+ and H2+. By comprehensive analysis, the efficacy of the two different types of synthesized two-color pulses (ω - 2ω and ω - 3ω) are analyzed with respect to one-color intense pulses in terms of controlling the probability modulation and electron localization asymmetry and compared with previous theoretical calculations and experimental findings. Through the detailed investigation, we have addressed which one is the major controlling knob to have better electron localization as well as probability modulation.

Towards a Warm Holographic Equation of State by an Einstein–Maxwell-Dilaton Model

The holographic Einstein–Maxwell-dilaton model is employed to map state-of-the-art lattice QCD thermodynamics data from the temperature (T) axis towards the baryon–chemical potential (μB) axis and aims to gain a warm equation of state (EoS) of deconfined QCD matter which can be supplemented with a cool and confined part suitable for subsequent compact (neutron) star (merger) investigations. The model exhibits a critical end point (CEP) at TCEP=O(100) MeV and μBCEP=500…700 MeV with an emerging first-order phase transition (FOPT) curve which extends to large values of μB without approaching the μB axis. We consider the impact and peculiarities of the related phase structure on the EoS for the employed dilaton potential and dynamical coupling parameterizations. These seem to prevent the design of an overall trustable EoS without recourse to hybrid constructions.

Photoelectron momentum distributions of triatomic CO2 molecules by circularly polarized attosecond pulses

Abstract Molecular-frame photoelectron momentum distributions (MF-PMDs) have been studied for imaging molecular structures. We investigate the MF-PMDs of CO2 molecules exposed to circularly polarized (CP) attosecond laser pulses by solving the time-dependent Schrödinger equations based on the single-active-electron approximation frames. Results show that high-frequency photons lead to photoelectron diffraction patterns, indicating molecular orbitals, these diffraction patterns can be illustrated by the ultrafast photoionization models. However, for the driving pulses with 30 nm, a deviation between MF-PMDs and theoretically predicted results of the ultrafast photoionization models is produced because the Coulomb effect strongly influences the molecular photoionization. Meanwhile, the MF-PMDs rotates in the same direction as the helicity of driving laser pulses. Our results also demonstrate that the MF-PMDs in a CP laser pulse are the superposition of those in the parallel and perpendicular linearly polarized cases. The simulations efficiently visualize molecular orbital geometries and structures by ultrafast photoelectron imaging. Furthermore, we determine the contribution of HOMO and HOMO-1 orbitals to ionization by varying the relative phase and the ratio of these two orbitals.

Electric vehicle and supply equipment adoption dynamics in the United States

In the present era of climate change concerns, plug-in electric vehicles (PEV) and their associated infrastructure are strategic investments by many governments. Investment discussions often include the dynamic supply-demand relationship between PEV adoption and charging station deployment, but rarely is it given an empirical treatment. We make use of publicly available charging station installation and PEV vehicle registration data by U.S. County between the years 2012 and 2021 to examine the phasing and causal relationship between adoption trends in these two markets. Non-linear Granger causality tests suggest a feedback relationship between PEV vehicle adoption and charging station installations. It can be further explained that when individuals adopt PEV, the demand for the charging infrastructure increases to meet the demand for PEV. Conversely, when more charging station installations become available, it encourages adoption of this technology making it convenient for individuals to have access to these charging facilities. It is observed in aggregate that PEVs are penetrating across the U.S., but the penetration rate differs across states and counties. We examine this interaction using a generalized propensity score (GPS) identification strategy for the effect of charging station installations on PEV registrations, coupled with a generalized additive model (GAM) to construct a causal dose-response curve. We observe statistically significant effects on per capita charging station rates for income and total population. We suggest a policy package that includes charging infrastructure investments but also provides wider adoption of subsidies for low-income households across all states.

The Nd-Fe-Rh system: Phase relations determination at 600 ℃ and magnetic property measurement of related compounds

The isothermal section of the Nd-Fe-Rh system at 600 ℃ was constructed based on the phase identification and analysis results from annealed alloys using X-ray diffraction and Scanning electron microscopy equipped with Energy dispersive spectroscopy. Two previously reported binary compounds, Nd4Rh and Fe2Nd, could not be confirmed. No new ternary compounds were found in the isothermal section. In the present work, the homogeneity ranges of the Fe-Rh binary system were redefined using phase disappear method, which were determined to be about 70–100 Fe at%, 51–69 Fe at%, 0–45 Fe at% for the single-phase region α-Fe, FeRh and γ-(Rh, Fe), respectively. It was confirmed that the maximum solid solubility of Fe in NdRh2, Nd3Rh and Nd7Rh3 is about 15.6 at% Fe, 4.0 at% Fe and 3.1 at% Fe, respectively, while no appreciable solubility was observed for the other binary compounds in the Nd-Fe-Rh system. The isothermal section of the Nd-Fe-Rh ternary system at 600 ℃ consists of 13 single-phase regions, 23 two-phase regions, and 11 three-phase regions. It suggests the presence of predominant antiferromagnetic exchange interaction in the NdRh compound. For the 38Nd-8Fe-54Rh sample, two magnetic entropy change peaks originate from the combined contribution from two magnetic phase transitions, an antiferromagnetic-paramagnetic transition and a ferromagnetic-paramagnetic transition for NdRh and NdRh2 phase, respectively.

Point-contact spectroscopy of Leggett modes in superconducting compounds with unconventional pairing

Proximity-coupled nanostructures of conventional superconductors (SCs) and half-metallic ferromagnets (hmFs) are promising candidates as materials with unconventional superconductivity. The interrelated superposition of spin singlet-triplet and frequency even-odd superconducting condensates characterizes the superconducting state in such heterostructures. In a multi-band SC, the collective modes associated with the excitations of the relative phase between superconducting bands without perturbation of the Cooper pairs symmetry (Leggett modes) are allowed. In this report, we present the results of experimental investigations via the point-contact transport measurements of the Leggett-like collective excitations in the superconducting state of the nanocomposite of s-wave two-band superconductor MgB2 and half-metallic ferromagnet (La,Sr)MnO3. Two types of point contacts (PCs) have been used: the nanocomposite-nonmagnetic metal PCs and the nanocomposite–hmF PCs. The conductance equidistant peaks against the background of the gap structure were observed in both types of high-quality point junctions. Their distinctive feature was their period: two times shorter for the nanocomposite–hmF contacts compared to the nonmagnetic metal PCs. We attribute these spin-selective conductance periodic peaks to the relative phase Leggett’s excitations between “parents” MgB2 even-frequency singlet condensates and proximity-induced triplet superconducting condensates. The data obtained on the hmF PCs also demonstrate the features that may indicate a dynamic coupling between even-frequency condensates and odd-frequency gapless superconducting condensates.

Universal Targeted Haplotyping by Droplet Digital PCR Sequencing and Its Applications in Noninvasive Prenatal Testing and Pharmacogenetics Analysis.

The analysis of haplotypes of variants is important for pharmacogenomics analysis and noninvasive prenatal testing for monogenic diseases. However, there is a lack of robust methods for targeted haplotyping. We developed digital PCR haplotype sequencing (dHapSeq) for targeted haplotyping of variants, which is a method that compartmentalizes long DNA molecules into droplets. Within one droplet, 2 target regions are PCR amplified from one template molecule, and their amplicons are fused together. The fused products are then sequenced to determine the phase relationship of the single nucleotide polymorphism (SNP) alleles. The entire haplotype of 10s of SNPs can be deduced after the phase relationship of individual SNPs are determined in a pairwise manner. We applied dHapSeq to noninvasive prenatal testing in 4 families at risk for thalassemia and utilized it to detect NUDT15 diplotypes for predicting drug tolerance in pediatric acute lymphoblastic leukemia (72 cases and 506 controls). For SNPs within 40 kb, phase relation can be determined with 100% accuracy. In 7 trio families, the haplotyping results for 97 SNPs spanning 185 kb determined by dHapSeq were concordant with the results deduced from the genotypes of both parents and the fetus. In 4 thalassemia families, a 19.3-kb Southeast Asian deletion was successfully phased with 97 downstream SNPs, enabling noninvasive determination of fetal inheritance using relative haplotype dosage analysis. In the NUDT15 analysis, the variant status and phase of the variants were successfully determined in all cases and controls. The dHapSeq represents a robust and scalable haplotyping approach with numerous clinical and research applications.

Pore-scale investigation of injectivity impairment caused by oil droplets during produced water reinjection using volume of fluid method

Produced water from subsurface may often contain oil droplets, even when not directly extracted from oil wells. Oil droplets can migrate into water-bearing stratigraphic layers, leading to the generation of oily water. This study evaluates the dynamic clogging behavior of oil droplets concerning various injection fluid properties, including injection velocity, interfacial tension, oil droplet size, concentration, viscosity, and medium wettability. The primary objective is to validate common clogging mechanisms associated with oil droplets and quantitatively assess the impact of these parameters on injectivity impairment within porous media. To achieve this, a volume of fluid approach is employed, integrating fluid interfacial properties to account for coalescence and surface adherence. The results are then compared to similar findings in existing literature. Our study reveals that increasing the capillary number enhances injectivity, up to a critical point where the flow regime attains optimal stability, contingent upon relative permeability and phase mobility. Investigation into system wettability demonstrates that while contact angle significantly affects the injectivity index, the impact on injectivity diminishes when altering it beyond 90°. Aligning droplet viscosity with that of the displacing fluid proves to be an effective solution for minimizing injectivity impairment, nearly eliminating damage. This research provides valuable insights into commonly studied emulsion parameters, like Jamin Ratio and oil concentration, and underlines the importance of investigating less-explored factors, such as wettability and oil viscosity, particularly in scenarios involving unstabilized droplets and coalescence dynamics.

Cross-Scale Phase Relationship of the Ca II K Index with Solar Wind Parameters: A Space Climate Focus

The solar wind, representing one of the most impacting phenomena in the circum-terrestrial space, constitutes one of the several manifestations of the magnetic activity of the Sun. With the aim of shedding light on the scales beyond the rotational period of the Sun (i.e., Space Climate scales), this study investigates the phase relationship of a solar activity physical proxy, the Ca II K index, with solar wind properties measured near the Earth, over the whole space era (last five solar cycles). Using a powerful tool such as the Hilbert–Huang transform, we investigate the dependence of their phase coherence on the obtained time scale components. Phase coherence at the same time scales is found between all the components and is also preserved between adjacent components with time scales ≳ 2 yrs. Finally, given the availability of the intrinsic modes of oscillation, we explore how the relationship of Ca II K index with solar wind parameters depends on the time scale considered. According to our results, we hypothesize the presence of a bifurcation in the phase-space Ca II K index vs. solar wind speed (dynamic pressure), where the time scale seems to act as a bifurcation parameter. This concept may be pivotal for unraveling the complex interplay between solar activity and solar wind, bearing implications from the prediction and the interpretation point of view in Space Climate studies.

Coherent polarization control of terahertz emission from graphene under excitation of two-color co-circularly polarized laser fields.

Coherent polarization control of terahertz (THz) emission is crucial for applications in the THz field. Here, we demonstrate that the polarization of THz waves emitted from graphene through quantum interference can be coherently controlled by varying the relative phase between the co-circularly polarized laser fields. The polarization state of the THz wave emitted from graphene remains linearly polarized, while its direction can be arbitrarily changed by varying the relative phase. This work not only achieves the coherent polarization control of the THz waves emitted from graphene but also promotes the fundamental research of THz photonics in graphene.

Dolostone-barite-phosphorite sequence in the basal Doushantuo Formation: Origin and implications for post-Marinoan ocean chemistry and phosphogenesis

Barite (BaSO4) represents a major component of many post-Marinoan cap dolostones worldwide, recording important information on climate upheavals during the terminal Neoproterozoic. However, its origins and relations with other lithofacies remain to be explored. Here we report new occurrences of barite in the basal Ediacaran Doushantuo Formation at a major phosphate mine in Weng'an, South China, and present results of detailed petrographic and geochemical investigations on the barites and related phases. At the outcrop scale, barite is mainly present as a 1–2 cm-thick layer at the contact of the cap dolostones and overlying phosphorites. Detailed petrographic observations reveal a lithofacies transition from dolostone through a mixture of barite, dolomite and apatite to barite and finally to granular phosphorite. The barites can be categorized into three generations in stratigraphic order, which are present as loose, randomly-oriented blades (B1), dense aggregates (B2), and radially aligned crystal fans (B3), respectively. B1 is dispersed in a matrix of apatite and dolomite, which has an average δ13Ccarb of −0.61‰. This, along with the common presence of organic matter (OM) in this barite, point to a possible source of Ba from organic degradation. B3 forms a centimeter-scale layer of barite fans that laterally extends over the entire mining pit, whereas B2 is locally distributed between B1 and B3, and occurs as relatively unoriented aggregates. δ34S values of B3 show a narrow range between +25.9‰ and +30.9‰, which is similar to that of contemporaneous seawater and indicate a seawater source of sulfate in barite. Based on the present investigation and a compilation of published data, we propose that B1 is diagenetic barite with a main source of Ba from degradation of organic matter and possibly also from dissolution of previous pelagic barite, whereas B2 and B3 represent seafloor precipitates that resulted from interactions between deep, anoxic Ba-rich waters and oxic, sulfate-rich surface waters during the post-glacial transgression. This episode of barite precipitation was immediately followed by massive accumulations of phosphorites in Weng'an and many areas of South China. The consecutive deposition of cap dolostone, barite and phosphorite signifies the transition from an alkalinity-rich, stagnant anoxic ocean to a dynamic marine regime featuring oxygenated surface waters and upwelling currents. These pH and redox changes likely facilitated the cycling and enrichment of phosphate in the shallow waters that was necessitated by the unprecedented accumulation of Ediacaran phosphorites in South China.

Programmable generation of counterrotating bicircular light pulses in the multi-terahertz frequency range

The manipulation of solid states using intense infrared or terahertz light fields is a pivotal area in contemporary ultrafast photonics research. While conventional circular polarization has been well explored, the potential of counterrotating bicircular light remains widely underexplored, despite growing interest in theory. In the mid-infrared or multi-terahertz region, experimental challenges lie in difficulties in stabilizing the relative phase between two-color lights and the lack of available polarization elements. Here, we successfully generated phase-stable counterrotating bicircular light pulses in the 14–39 THz frequency range circumventing the above problems. Employing spectral broadening, polarization pulse shaping with a spatial light modulator, and intra-pulse difference frequency generation leveraging a distinctive angular-momentum selection rule within the nonlinear crystal, we achieved direct conversion from near-infrared pulses into the designed counterrotating bicircular multi-terahertz pulses. Use of the spatial light modulator enables programmable control over the shape, orientation, rotational symmetry, and helicity of the bicircular light field trajectory. This advancement provides a novel pathway for the programmable manipulation of light fields, and marks a significant step toward understanding and harnessing the impact of tailored light fields on matter, particularly in the context of topological semimetals.