Browse Articles

Reconfigurable generation of order-controllable acoustic orbital angular momentum beams

Acoustic vortex beams carrying orbital angular momentum (OAM) have attracted a broad research interest in the past 20 years. Due to the orthogonality of OAM beams with different orders, a wealth of interesting applications have been developed, including communications, particle manipulation, and imaging. Although many techniques have been reported to generate acoustic OAM beams, it still remains a formidable challenge to generate reconfigurable and order-controllable OAM beams via a cost-effective manner. In this work, we propose a balanced-ternary-based approach to generate reconfigurable order-controllable acoustic OAM beams in water. We cascade three engineered spiral phase plates and manipulate them in a reconfigurable manner to generate 26 different OAM modes at ultrasonic frequencies. Experimental results demonstrate the good quality and high purity of all the generated OAM beams. According to this method and theory, we can flexibly extend our design to generate acoustic OAM beams with arbitrarily high orders. This work provides a new paradigm for the reconfigurable and order-controllable generation of acoustic OAM beams and may facilitate many OAM-based applications.

Science takes on the world’s most lethal malignancy

Bacillus halotolerans XJ-1 inhibits the fungal pathogen Fusarium asiaticum while promoting the growth of maize

Abstract This study explored the potential of Bacillus halotolerans XJ-1 as a biocontrol agent against Fusarium asiaticum , the pathogen of maize stem base rot. Pot experiments were conducted to determine the morphological and physiological indicators of corn treated with and without strain XJ-1, and the incidence rate, disease index, and relative control efficacy were calculated. The effects of the fermentation filtrate of XJ-1 on the reactive oxygen species content and the activities of related defense enzymes of F. asiaticum were determined. Compared with the treatment of only inoculating F. asiaticum , only inoculating XJ-1 for biological enhancement significantly alleviated the severity of maize stem base rot and reduced the disease incidence. The protective and therapeutic efficacy of XJ-1 against F. asiaticum was 61.7% and 56.3%, respectively. Compared with the control, XJ-1 significantly promoted the growth of corn with an increase of plant height, stem diameter, dry and fresh weight of leaves, leaf length, leaf width, and leaf area by 32.30%, 33.33%, 24.48%, 32.14%, 40.66%, 20.92%, and 28.95%, respectively. The contents of chlorophyll, soluble protein, soluble sugar, nitrate nitrogen, and inorganic phosphorus in the leaves all increased significantly by 1.75, 1.29, 1.07, 1.47, and 1.40 times that of the control, respectively. The fermentation filtrate of XJ-1 significantly increased the contents of hydrogen peroxide and superoxide anion, along with the clearance rate of the hydroxyl radical, whereas the activities of superoxide dismutase, peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase were significantly reduced. Moreover, XJ-1destroyed the hyphae and cell structure of F. asiaticum , leading to depression, dryness, uneven thickness, and leakage of cell contents. Therefore, strain XJ-1 has a significant promoting effect on corn plants suffering from corn stem base rot with potential application value in biological control and agricultural production.

Theoretical-computational modeling of the vibrational chirality of interacting chromophores: VCD signal and equilibrium properties of excitonic <i>clusters</i>

In this work, we extend the perturbed matrix method combined with molecular dynamics simulations, to the modeling of Vibrational Circular Dichroism (VCD) spectra, including non-covalent excitonic coupling among distinct molecular chromophores. The method is applied to (R)-propylene oxide as a benchmark system, comparing infinite-dilution conditions with highly concentrated solutions in water and carbon tetrachloride. The calculated VCD spectra show very good agreement with experimental data and only weak concentration dependence. However, analysis of the excitonic eigenstates reveals the formation of transient, thermally populated excitonic clusters characterized by delocalized vibrational excitations and widely dispersed rotatory strengths. The equilibrium distribution and free-energy profile of these clusters are characterized, providing microscopic insights into excitonic effects in VCD spectra of soft condensed-phase systems.

Zanidatamab with and without Tislelizumab in HER2-Positive Gastroesophageal Cancer

Effect of Ga composition of a Ga–Na melt on the dislocation density in the coalescence region of GaN crystals grown by the Na-flux multi point seed technique

Low threading dislocation density (TDD) GaN substrates are essential for fabricating vertical GaN power devices. In this study, we fabricated large-diameter, low-TDD GaN wafers using the Na-flux multipoint seed (MPS) method. However, the MPS method leads to regions with high-TDD values (&amp;gt;105 cm−2) at the crystal coalescence regions. We focused on the Ga composition of a Ga–Na melt and investigated TDD reduction by modifying the crystal growth mode. As the Ga composition was reduced from 27 to 19 mol. %, crystal shape uniformity improved, and the maximum TDD above the coalescence regions decreased from 4.41 × 105 to 3.01 × 105 cm−2. This reduction suggests that the improved shape uniformity promotes the efficient concentration of dislocations toward the coalescence boundaries. We also found that reducing the Ga composition effectively suppressed the formation of inclusions in the GaN crystals, contributing to the reduction of inclusion-induced dislocations. At 19 mol. % Ga composition, the mean TDD in regions excluding coalescence boundaries was in the low 104 cm−2 range. These findings are expected to contribute to the fabrication of high-quality GaN substrates using the Na-flux method.

The effects of Rashba spin-orbit and non-linear electron-phonon interactions on impurity-induced bound states in BCS superconductors

Abstract We have theoretically studied the influence of linear, non-linear electron-phonon interactions and Rashba spin orbit interaction on formation of the localized magnetic moment and subgap Yu-Shiba-Rusinov bound state for a single-level quantum impurity embedded in an s-wave Bardeen-Cooper-Schrieffer superconductor, modeled by single-impurity Anderson-Holstein Hamiltonian. We have used time-scale separation approach combined with Bogoliubov transformation and modified Lang-Firsov transformation to decouple quadratic and linear electron-phonon interactions present on impurity. Then we used the Kikuchi-Morita cluster variation method for the calculation of ground state energy of the system. We theoretically studied the influence of Rashba spin-orbit interaction on the correlation effects of magnetic impurity embedded in an s-wave superconductor. Further, we analyze transition from single to bipolaron phase transition at the impurity site as a function external tunable Rashba spin orbit interaction strength.

Dynamically heterogeneous segmental dynamics in poly(vinyl butyral) under plasticization and antiplasticization: The mechanism behind cohesive energy and chain flexibility

Plasticizers and antiplasticizers are essential additives used to tailor the processability and microstructure of polymeric materials, while the complicated effects of chain flexibility and cohesive energy density (CED) on the heterogeneous dynamics remain poorly understood. Here, we compare the segmental dynamics of plasticized and antiplasticized poly(vinyl butyral) (PVB), which exhibits dynamic heterogeneity. It was found that the addition of either a plasticizer or an antiplasticizer leads to a deviation from the empirical inverse correlation between the fragility index m and the stretching exponent βKWW, indicating that changes in βKWW alone cannot reliably reflect variations in m. Although both “fast” and “slow” regions show remarkable reduction in glass transition temperature Tg and m, the “slow” regions with relatively restricted mobility possess a higher Tg while a lower m regardless of plasticization or antiplasticization because of their higher CED. Moreover, plasticized samples exhibit a more pronounced reduction in Tg and m for both “fast” and “slow” regions compared to antiplasticized ones, suggesting that chain flexibility acts as an additional factor reducing fragility. These findings provide strong experimental evidence for the roles of chain flexibility and CED in regulating segmental dynamics in either plasticized or antiplasticized PVB, thus providing new insights into the fabrication of strong polymeric glasses and high-performance materials.

Acute Esophageal Necrosis

THz near-field spatial mapping of dipole–dipole interactions in free space and near interfaces

Dipole–dipole interactions are central to energy-transfer processes. Understanding the interaction dynamics is essential across diverse fields, including solar energy harvesting, organic light-emitting diodes, long-range energy transport, and molecular biosensing. Such interactions are fully described by the photonic Green function, which defines the electromagnetic response of a point dipole source. However, direct experimental access to the individual components of Green’s function at the single-dipole level remains challenging. Here, we employ a double-probe terahertz (THz) near-field microscope to directly map the dipole–dipole interactions in free space and near a resonant dielectric interface formed by a pellet of α-lactose and air. In free space, we observe highly anisotropic energy-transfer dynamics arising from the non-radiative near-field contribution of Green’s function, including the pronounced suppression associated with the magic-angle condition. Near the air/α–lactose interface, we reveal strong modifications of Green’s function along both the in-plane and out-of-plane directions: a reduction in the energy-transfer rate near the vibrational resonance of the medium and pronounced oscillations in intensity and phase due to interference between the direct dipole–dipole interaction and the surface-mediated contribution. Our results provide direct access to the non-radiative components of Green’s function and establish a powerful framework for probing and engineering dipole–dipole interactions in complex and resonant photonic media.

Modeling the impact of rural infrastructure on the population of rural settlements: a case study of Saqqez County, Iran

Quantum interference in ring-structured molecular junctions: Effects of electron–phonon coupling and lattice dynamics

We investigate the quantum interference (QI) effects in molecular junctions with ring geometry, focusing on the role of electron–phonon (e–ph) coupling and lattice dynamics, using the extended Su–Schrieffer–Heeger model combined with the hierarchical equations of motion approach. In an ideal uniform lattice without e–ph coupling, the current exhibits a clear even–odd dependence on the atom number difference Δ between the two branches, with constructive quantum interference (CQI) for even Δ/2 and destructive quantum interference (DQI) for odd Δ/2. Under frozen-lattice conditions, slight lattice reconstruction induced by the e–ph coupling weakens both CQI and DQI by modifying the phase accumulation along the transport pathways. In contrast, dynamical lattice evolution leads to a pronounced suppression of DQI by continuously disrupting the phase relation between interfering pathways. Moreover, lattice dynamics facilitate the formation of excitonic states, providing additional assisted transport channels and enhancing the current in both CQI and DQI regimes. Our results demonstrate that QI in molecular junctions is governed not only by pathway geometry but also by e–ph coupling and lattice dynamics, highlighting the crucial role of vibronic effects in nanoscale transport.

Ultrasound-Facilitated, Catheter-Directed Fibrinolysis for Acute Pulmonary Embolism

High-pressure sintering driven defect modulation for enhanced thermoelectric performance in Li+/S2− co-doped Cu2Se

As a typical ionic crystal exhibiting liquid-like behavior, p-type semiconductor Cu2Se has been a research hotspot in thermoelectric materials due to its low thermal conductivity. In this work, by varying the temperature and pressure conditions during synthesis, different morphologies and quantities of microstructural defects were introduced in Li+ and S2− co-doped copper selenide samples. The influence of these defects on the thermoelectric performance of the samples was subsequently investigated. The synthesized samples were characterized for their phase composition, microstructure, electrical transport properties, thermal transport properties, and thermoelectric performance. The results indicate that cracks are the primary defects in samples sintered at high temperature and atmospheric pressure, while impurity phases and micron-sized pores are the main defects in samples sintered under high pressure and low temperature. These defects significantly affect the electrical and thermal transport properties of the doped Cu2Se samples. The presence of residual Cu3Se2 and elemental Cu in the sample sintered at 5 GPa/room temperature leads to anomalous electrical transport behavior. When the pressure and temperature exceed 5 GPa and 1200 °C, the shape of pore defects is markedly altered, their number is reduced, and the propagation of crack defects is simultaneously suppressed. By employing Li+ and S2− co-doping combined with high-temperature and high-pressure sintering, the ZT value of the doped Cu2Se material was enhanced from 2.1 to a maximum of approximately 2.4.

Big data technology application and carbon emission efficiency of manufacturing enterprises

The coherent-state transformation in quantum electrodynamics coupled cluster theory

We analyze the coherent-state (CS) transformation in quantum electrodynamics coupled cluster (QED-CC) theory from the perspective of its non-vanishing commutator with the polaritonic cluster operator. In particular, we show that a QED Hartree–Fock (QED-HF) reference state parameterized by the CS transformation leads to a QED-CC Lagrangian formally determined by CS-representations of polaritonic Hamiltonian, polaritonic cluster, and polaritonic de-excitation operators. The approach proposed herein differs from the original formulation of QED-CC theory in the definition of the photon state basis and exploits photon-added coherent states in contrast to previously considered displaced number states. We find a renormalization of both QED-CC correlation energy and QED-CC ground state induced by the CS transformation, which depends on the mean-field expectation value of the molecular dipole operator and, therefore, breaks origin invariance for charged systems. Electronic contributions to correlation energy and QED-CC ground state are renormalized by CS-transformed mixed excitation and de-excitation operators. In contrast, the CS-transformed single-photon excitation affects only the QED-CC ground state but not directly the correlation energy. The renormalized QED-CC ansatz becomes similar to the original QED-CC formulation for large cavity frequencies, leading to small renormalization corrections. A divergent renormalization energy for molecules with a non-vanishing molecular dipole moment is found in the low-frequency limit, which we discuss with respect to multi-photon excitations in the polaritonic cluster operator and the relevance of the cavity-Born–Oppenheimer framework.

When Race Matters

On mechanism of phase stabilization in ferroelectric and high- <i>k</i> HfO2

We present a systematic first-principles study of dopant-induced phase stabilization in HfO2 across ferroelectric (FE) and non-ferroelectric polymorphs for a large set of dopants. To overcome the strong configuration dependence of defect energetics, we develop a multi-stage screening workflow that identifies low-energy dopant–vacancy configurations. In an equilibrated-solution [“PVD” (physical vapor deposition)] model, bulk T = 0 K energetics indicate that ionically compensated doping alone is insufficient to stabilize the orthorhombic-ferroelectric phase over the monoclinic phase; certain dopants even increase its relative energy. Configurational-entropy corrections are small at device-relevant temperatures, and vibrational contributions—benchmarked against explicit phonon calculations—primarily stabilize the tetragonal phase, remaining inadequate to reverse bulk phase ordering at moderate anneal temperatures. We further observe that many rhombohedral-FE supercells lose phase identity upon relaxation, typically collapsing toward orthorhombic-FE motifs, underscoring sensitivity to local defect arrangements. To assess deposition effects, we introduce a planar (“atomic layer deposition”) model that mimics dopant layering; it amplifies dopant-identity sensitivity and can reshape phase competition compared to the equilibrated-solution limit. Overall, our results suggest that experimentally observed ferroelectric stabilization in thin films arises from a combination of interfacial/finite-size terms and deposition-induced dopant distributions, rather than bulk thermodynamics alone.

Protective effects of BPC 157 in rats with experimentally induced lower extremity ischemia-reperfusion injury

Evidence of orbital mixing upon ionization via Cooper minimum photoelectron dynamics in epichlorohydrin. Experiment and theory

A peculiar electron correlation effect, leading to orbital rotation upon ionization, theoretically predicted long ago, was never experimentally characterized. The effect is expected to appear prominently in the photoionization of chiral molecules, due to the lack of symmetry constraints on wave-function mixing. This is observed to have a profound effect on the photoelectron dynamics, as here demonstrated by investigating the β asymmetry parameter and partial cross-section observables in the Cl 3p Cooper minimum region of epichlorohydrin, a chiral prototype system. Angle-resolved photoelectron spectroscopy with tunable synchrotron radiation allowed measuring Cooper minimum β oscillations, which were observed for solely two valence photoionization channels. The nature and number of channels exhibiting such dynamical behavior, along with the extent of the observed oscillation amplitudes, could not be accounted for by predictions based on Hartree–Fock and density functional theory. These features could only be explained by incorporating correlation effects, which mix single-hole configurations of identical symmetry, in the characterization of the four lowest-lying molecular cation states via equation-of-motion coupled-cluster-singles-and-doubles Dyson orbitals.