Breaking Effects Research Articles

Effect of microwave irradiation on the breaking and linear cutting of hard rock

Microwave technology, emerging as a novel approach to rock-breaking, holds significant promise in the realm of auxiliary mechanical pick rock breaking. In view of the problems existing in the hard rock breaking such as low efficiency and difficulty in one-time cutting, this study conducted experimental research using a method combining microwave irradiation and linear cutting with conical picks. The comprehensive temperature distribution of the rock is reproduced by 3D technology after microwave irradiation, defined the high-temperature zone and calculated the surface area. Moreover, analyzing the relationship between temperature and cutting force. And the effect of microwave-assisted conical pick rock breaking was quantified in terms of cutting force, rock breaking effect, and energy consumption. The results indicate that microwave irradiation induces heating in hard rock, leading to the formation of fissures and even partial fragmentation of rocks. The thermal damage effect of microwave is determined by the differences in the physical and mechanical properties of different rocks. In the experiment, basalt has the best heating effect and sandstone has the best fracturing effect. Compared to non-microwave, microwave (6 kW,60 s) irradiation reduces the cutting force, improves the effect of rock breaking, and reduces the work done (E) by the cutting force and the mechanical specific energy (MSE). Microwave irradiation-assisted mechanical rock breaking is better for sandstone, moderate for basalt, and inferior for granite in this study.

Two-Dimensional Superconductivity and Anomalous Vortex Dissipation in Newly Discovered Transition Metal Dichalcogenide-Based Superlattices.

Properties of layered superconductors can vary drastically when thinned down from bulk to monolayer owing to the reduced dimensionality and weakened interlayer coupling. In transition metal dichalcogenides (TMDs), the inherent symmetry breaking effect in atomically thin crystals prompts novel states of matter such as Ising superconductivity with an extraordinary in-plane upper critical field. Here, we demonstrate that two-dimensional (2D) superconductivity resembling those in atomic layers but with more fascinating behaviors can be realized in the bulk crystals of two new TMD-based superconductors Ba0.75ClTaS2 and Ba0.75ClTaSe2 with superconducting transition temperatures 2.75 and 1.75 K, respectively. They comprise an alternating stack of H-type TMD layers and Ba-Cl layers. In both materials, intrinsic 2D superconductivity develops below a Berezinskii-Kosterlitz-Thouless transition. The upper critical field along the ab plane () exceeds the Pauli limit (μ0Hp); in particular, Ba0.75ClTaSe2 exhibits an extremely high ≈ 14 μ0Hp and a colossal superconducting anisotropy (/) of ∼150. Moreover, the temperature-field phase diagram of Ba0.75ClTaSe2 under an in-plane magnetic field contains a large phase regime of vortex dissipation, which can be ascribed to the Josephson vortex motion, signifying an unprecedentedly strong fluctuation effect in TMD-based superconductors. Our results provide a new path toward the establishment of 2D superconductivity and novel exotic quantum phases in bulk crystals of TMD-based superconductors.

Lorentz-violating Yukawa theory at finite temperature

This paper addresses Yukawa theory, focusing on the scattering between two identical fermions mediated by an intermediate scalar boson, considering the effects of thermal contributions and Lorentz symmetry breaking. Temperature is introduced into the theory through the thermofield dynamics formalism, while Lorentz violation arises from a background tensor coupled to the kinetic part of the Klein-Gordon Lagrangian. Two important quantities are calculated: the cross section for the scattering process and the modified Yukawa potential. The main results obtained in this work demonstrate that considering Lorentz symmetry breaking has several implications for changes in symmetries and physical states, while the presence of temperature is strongly related to the strength of the interaction. This interplay between symmetry breaking and temperature effects provides deeper insights into the behavior of the Yukawa theory under different conditions. Published by the American Physical Society 2024

Engineering Two-Dimensional Magnetic Heterostructures: A Theoretical Perspective.

Two-dimensional (2D) magnetic materials have attracted great attention due to their promise for applications in future high-speed, low-energy quantum computing and memory devices. By integrating 2D magnetic materials with other magnetic or nonmagnetic materials to form heterostructures, the synergistic effects of interlayer orbital hybridization, spin-orbit coupling, and symmetry breaking can surpass the performance of single-layer materials and lead to novel physical phenomena. This review provides a comprehensive theoretical analysis of engineering 2D magnetic heterostructures, emphasizing the fundamental physics of interlayer interactions and the resulting enhancements and novel properties. It reviews the mechanisms and progress in tuning the magnetic ordering, enhancing the Curie temperature (Tc) and modulating properties such as topological magnetic structures, spin polarization, electronic band topology, valley polarization, and magnetoelectric coupling through the construction of 2D magnetic heterostructures. Additionally, this review discusses the current challenges faced by 2D magnetic heterostructures, aiming to guide the future design of higher-performance magnetic heterostructures.

Topological amplitudes of charmed baryon decays in the SU(3)F limit

Charmed baryon decay plays an important role in studying the weak and strong interactions. Topological diagram is an intuitive tool for analyzing the dynamics of heavy hadron decays. In this work, we investigate the topological diagrams of charmed baryon antitriplet (Bc3¯) decays into a light baryon octet (B8) and a light meson (M). A one-to-one mapping between the topological diagram and the invariant tensor is established. The topological diagrams of the Bc3¯→B8SM modes (where B8S and B8A are the q1↔q2 symmetric and antisymmetric octets) and the diagrams with a quark loop are presented for the first time. The completeness of topologies is confirmed by permutation. The linear relations of topologies are obtained by deriving the relation between the topological amplitudes constructed by the third- and second-rank octet tensors. It is found the topologies contributing to the Bc3¯→B8SM modes can be determined by the topologies contributing to the Bc3¯→B8AM modes, and vice versa. The equations of SU(3) irreducible amplitudes decomposed by topologies are derived through two different intermediate amplitudes. However, the inverse solution does not exist since the number of topologies exceeds number of SU(3) irreducible amplitudes. Applying this framework to the Standard Model, it is found there are thirteen independent SU(3) irreducible amplitudes contributing to the Bc3¯→B8M decays. Among these, four amplitudes associated with three-dimensional operators are significant for CP asymmetries. Considering the suppressions due to small Cabibbo-Kobayashi-Maskawa matrix elements and the Körner-Pati-Woo theorem, the branching fractions of charmed baryon decays are dominated by five SU(3) irreducible amplitudes in the SU(3)F limit. Quark-loop diagrams could enhance the U-spin breaking effects and increase the branching fraction difference of two decay channels. Systematic measurements of branching fractions of the singly Cabibbo-suppressed modes could help identify promising channels for searching for CP asymmetries in the charmed baryon sector. Published by the American Physical Society 2024

The resistivity of rare earth impurities diluted in Lanthanum, Part I

We study the temperature-independent resistivity of rare-earth magnetic impurities (Gd, Tb, Dy) and the non-magnetic impurity (Lu) diluted in double hexagonal close-packed (dhcp) lanthanum. We model the system as a two-band system, where s-electrons perform conduction while d-electrons entirely screen the charge differences induced by impurities. Using the T-matrix formalism derived from the Dyson equation, we obtain an expression for resistivity. Since electronic properties are highly sensitive to band structure, we examine two types: a simplified “parabolic” band structure and a more realistic one obtained through first-principles calculations using VASP. Our results indicate that the exchange parameters, represented as cross products, significantly influence the magnitude of the spin resistivity term. Furthermore, we find that the role of band structure in resonant scattering and the formation of virtual bound states depends on the specific band structure employed. Additionally, our study addresses the effects of translational symmetry breaking and the excess charge introduced by rare-earth impurities on resistivity.

Linear and nonlinear coupling of light in twin-resonators with Kerr nonlinearity

Nonlinear effects in microresonators are efficient building blocks for all-optical computing and telecom systems. With the latest advances in microfabrication, coupled microresonators are used in a rapidly growing number of applications. In this work, we investigate the coupling between twin-resonators in the presence of Kerr nonlinearity. We use an experimental setup with controllable coupling between two high-Q resonators and discuss the effects caused by the simultaneous presence of linear and nonlinear coupling between the optical fields. Linear-coupling-induced mode splitting is observed at low input powers, with the controllable coupling leading to a tunable mode splitting. At high input powers, the hybridized resonances show spontaneous symmetry breaking (SSB) effects, in which the optical power is unevenly distributed between the resonators. Our experimental results are supported by a detailed theoretical model of nonlinear twin-resonators. With the recent interest in coupled resonator systems for neuromorphic computing, quantum systems, and optical frequency comb generation, our work provides important insights into the behavior of these systems at high circulating powers.

Experimental studies of in-medium modification of [formula omitted] meson mass through [formula omitted] decays

ϕ meson is an ideal probe to explore mass modification inside the nucleus due to partial restoration of chiral symmetry with its narrow width. The modification of ϕ mass is related to the strange-quark condensate 〈s̄s〉 in a finite density. J-PARC E88 has been proposed as an experiment to study the modification of ϕ mass inside nuclei in proton–nucleus collisions. Complementary to ϕ→e+e− decay measurements at J-PARC E16, E88 will measure high-statistics ϕ→K+K− decays of about 1 M in p+C, p+Cu, and p+Pb collisions by deploying kaon identification detectors at forward angles in the E16 spectrometer. Utilizing the high-statistics data, the momentum and polarization dependence of mass modification will be studied to evaluate the strange quark condensate in nucleons, and Lorentz-symmetry breaking effects. In this paper, we will discuss physics goals, the experimental design and feasibility, the performance of kaon identification detectors, and the timeline of the E88.

Tailored Regulation of Graphite Microcrystals via Tandem Catalytic Carbonization for Enhanced Electrochemical Performance of Hard Carbon in the Low‐Voltage Plateau

AbstractThe sodium storage behavior in the plateau region is crucial for determining the capacity and rate capability of hard carbon (HC) anodes in sodium‐ion batteries (SIBs). Key structural features for achieving excellent plateau performance include extended graphite domains and increased interlayer spacing. However, synchronously optimizing these two structures is challenging due to their inherent trade‐off. Herein, a tandem catalytic carbonization strategy is developed to construct HC with long graphite domains (La = 5.31 nm) and large interlayer spacing (d002 = 0.389 nm) simultaneously. Comprehensive in situ and ex situ tests unravel the catalytic selective bond breaking and aromatization effects of ZnCl2, the catalytic graphitic layers enlargement and occupied effects of formed ZnO and Zn in different temperature stages, leading to the formation of the unique structure. The optimal HCZ‐0.1 exhibits a high reversible capacity of 346.9 mAh g−1 with a plateau capacity of 249.4 mAh g−1, and high‐rate performance (114.0 mAh g−1 at 5 A g−1). In addition, the sodium storage mechanism and origin of enhanced Na+ kinetics of HCZ‐0.1 are also revealed. This work offers a precise method to engineer the graphite microcrystal structure in HC for superior sodium storage in the plateau region.

Keeping dark modes dark: Reducing the effects of symmetry breaking at oblique incidence

Dark modes are defined by their lack of radiative coupling to the far field. However, the modes can be made to couple to far field radiation by symmetry breaking. For a resonant dimer, obliquely incident waves can create a phase difference in the currents between the elements, resulting in symmetry breaking. This work reduces symmetry breaking effects by minimizing the size of a dimer of dipolar elements with respect to its resonant wavelength. We obtain a mode that can experimentally be excited from the near field but has negligible excitation in the far field for obliquely incident waves. Such a mode could have use in wireless security applications.

Accretion of Vlasov gas onto a black hole in the Kalb–Ramond field

Abstract We investigate the accretion of Vlasov gas onto a static, spherically symmetric black hole (BH) influenced by the Kalb–Ramond (KR) field, focusing on the effects of Lorentz symmetry breaking (LSB) parameters. We employ the Maxwell–Jüttner distribution to model the gas at infinity and derive key quantities such as the particle current density and mass accretion rate. Our findings reveal that an increase in the LSB parameter results in a decrease in the mass accretion rate. We also present explicit formulations of the accretion rate in the high-temperature limit and find the result is quite different from the result in Bumblebee model.

Constraint of d = 8 Lorentz Invariance Violation with New Experimental Design

Short-range gravity experiments are more suitable for the testing of high-order Lorentz symmetry breaking effects. In our previous work, we proposed a new experimental design based on precision torsion balance technology to test the Lorentz violation force effect that varies inversely with the fourth power of distance (corresponding to mass dimension d = 6 term), and the corresponding experiment is currently underway. In this paper, we focus on analyzing the potential of this experimental scheme to test the Lorentz violation force that varies inversely with the sixth power of distance (corresponding to mass dimension d = 8 term). The results show that, compared with the current best limit, the new experimental scheme can improve the constraints on the Lorentz violation coefficients with d = 8 by at least one order of magnitude.

Optimization of Operating Parameters for Straw Returning Machine Based on Vibration Characteristic Analysis

For the mechanized technical mode of total wheat straw returning to field, there are problems such as large vibration during the operation of the straw returning machine that, in turn, affect the effect of stubble breaking. This study took the Tongtian 1-JHY-220 straw returning machine as the research object to conduct field experiments, with wheat stubble height, forward velocity, and PTO speed as experimental parameters. And the vibration characteristics at different positions of the machine and the final stubble breaking rate were used as evaluation indicators. Combined with the orthogonal experiment and response surface analysis method, this article analyzes and discusses the influence of various parameters on vibration characteristics and operational effectiveness. The results show that PTO speed and wheat stubble height were the main factors affecting the vibration and operation quality of the straw returning machine. Low PTO speed and high stubble height can improve the stubble breaking rate of the straw returning machine and reduce its operation vibration. Furthermore, the multi-objective optimization results show that when the forward velocity in the range of 8.5–9 km/h, the PTO speed is 540 r/min, and the stubble height is in the range of 200–250 mm, the stubble breaking rate of the straw returning machine is greater than 86%. At this time, the total vibration of the straw returning machine and tractor rear axle is relatively small. This study can lay a foundation for further studying the impact of the vibration of the straw returning machine on the stubble breaking effect and provide a reference for the preparation of high-quality seedbed under conservation tillage.

Symmetry Breaking and Modal Localization in a System of Parametrically Excited Microbeam Resonators

In this work, we study the nonlinear dynamics of parametrically excited bending vibrations of two weakly coupled beam microresonators under electrothermal excitation. A steady-state harmonic temperature distribution in the volume of the resonators in the frequency domain was obtained. A system of equations for mechanically coupled beam resonators is derived, considering the deposited particle on one of them. Using asymptotic methods of nonlinear dynamics, equations in slow variables were obtained, which were studied by methods of the theory of bifurcations. It is shown that in a perfectly symmetrical system in a certain frequency range, the effect of symmetry breaking is observed – the emergence of a mode with different amplitudes of oscillations of two beam resonators, which can be the basis for a new principle of high-precision measurements of weak disturbances of various physical natures, in particular – measurements of ultra-low masses of deposited particles.

Experimental study on the rock breaking effect of different tooth shapes of inserted teeth in a hobbing-cone hybrid PDC bit under complex stress environment

The hobbing-cone hybrid PDC bit has emerged with the increasing exploitation of deep oil and gas resources. As an important component of new bits, studying the mechanism of toothed fracturing of deep rocks is crucial for improving rock-breaking efficiency. In this paper, the spherical teeth and conical teeth were used to intrude sandstone under different confining pressures, and the brittleness index (BIm), specific energy (SE), and average fragment size (dm) were used to analyze the rock-breaking effect. The 3D contour scanner quantitatively analyzed the crushing pit area. Finally, the in-situ CT scanning and discrete element numerical simulation were used to summarize the crack propagation law. The results show that with the increase of confining pressure, the BIm of inserted teeth increases continuously, and the growth rate of conical teeth increases, while that of spherical teeth decreases. The SE and dm exhibit a symmetrical distribution with a confining pressure of 10MPa as the axis of symmetry. When the difference in principal stress is 5MPa, the SE is the lowest point, the rock-breaking efficiency is the highest, and the corresponding dm is at the highest point, but the curve trend is the opposite. When the stress difference is 5MPa, it is conducive to propagating surface cracks, thus forming a larger crushing area and the highest rock-breaking efficiency. Based on CT results, the dense particle core is formed near the inserted teeth, and that of the spherical teeth is located below. In contrast, that of the conical teeth is located on the side, which is also the reason for the difference in crack propagation between different tooth shapes.

Topological diagram analysis of [formula omitted] decays in the SU(3)F limit and beyond

Charm baryon decay plays an important role in studying non-perturbative baryonic transitions. Compared to other hadron multiplets, the flavor symmetry of baryon decuplet is more simple and attractive. In this work, we study the topological amplitudes of charmed baryon decays into decuplet baryon in the flavor symmetry and the linear SU(3)F breaking. It is found most of topological diagrams are suppressed by the Körner-Pati-Woo theorem in the SU(3)F limit. Only two independent amplitudes contributing to the Bc3‾→B10M decays, with one dominating the branching fractions. The Lee-Yang parameters of all Bc3‾→B10M modes are the same in the SU(3)F limit, and there are only four possible values for the CP asymmetries. After including the first-order SU(3)F breaking effects, the Ξc+→Σ⁎+K‾0 and Ξc+→Ξ⁎0π+ decays have non-zero branching fractions. The number of free parameter contributing to the Bc3‾→B10M decays in the linear SU(3)F breaking is smaller than the available data. The SU(3)F breaking part of the quark loop diagram can be extracted by global fitting of branching fractions, which could help us understand the CP violation in charm sector. Additionally, some new isospin equations are proposed to test the Körner-Pati-Woo theorem.

The effect of symmetry breaking in coupled cavity photonic crystal waveguide on dispersion characteristics

The effect of symmetry breaking in coupled cavity photonic crystal waveguide on dispersion characteristics

Study on the influence of slit pipe wall thickness on the rock breaking effect of slit charge explosion

AbstractIn this study, the influence of slit pipe wall thickness on shaped charge blasting efficiency was investigated. The influence of different slit pipe wall thicknesses on the dynamic behavior of slotted charge blasting was analyzed by a combination of experimental observations and numerical simulations. Polymethyl methacrylate (PMMA) was used as a rock simulation material to prepare slit pipes with different slit pipe wall thicknesses (0.5, 1.0, and 1.5 mm). A dynamic caustics system is used to capture the crack propagation process. ANSYS/LS‐DYNA was used for the numerical simulation analysis. The experimental results show that there is a positive correlation between the slit pipe wall thickness and the crack propagation length, velocity, and dynamic stress intensity factor. With increasing slit pipe wall thickness, the directional propagation and energy concentration ability of cracks are significantly improved, but an increase in the slit pipe wall thickness will also promote the propagation of secondary cracks. In addition, the numerical simulation results support the experimental observations and reveal the existence of an optimal slit pipe wall thickness that can maximize the blasting efficiency while maintaining structural integrity. This study not only deepens the understanding of the physical laws of the blasting process but also provides a practical reference for the optimal design of slotted charges in engineering applications.

Imitating pangolin scale structure for reducing adhesion and resistance of rotary tillage in wet-adhesive soil

The bionic design of soil-engaging components has recently received much attention in conservation tillage and is extremely important for reducing tillage resistance and increasing implement passability in wet-adhesive rice paddy soil. In this paper, to reduce adhesion and resistance of rotary tillage in wet-adhesive soil, a novel imitating pangolin scale structure is first proposed, and the bionic non-smooth surface parameters affecting the soil adhesion effect is clarified. Afterwards, based on the JKR attached Bonding contact model, an accurate discrete element interaction model of the designed rotary tillage blade -wet adhesive soil is established, and the effect of spindle speed, bump size and bump distance on the tillage resistance and soil disturbance is analyzed using the proposed model. Finally, the proposed imitating pangolin scale structure is optimized to improve the anti-adhesive and drag reduction properties using response surface method, furthermore, the corresponding model validation experiments and field tests are also conducted. Results reveal that the relative errors between the simulated and experimental values of the bionic blade rotary torque and soil adhesion mass are only respectively 4.4 % and 8.3 %. In addition, the optimal parameter combinations of anti-adhesion and drag reduction are also determined: the spindle speed is 180 rpm, the bump width is 10.6 mm and the bump distance is 17.9 mm, respectively, at the time, the effect of soil breaking of the designed blade is reduced by 9.95 % compared to that of the traditional blades but the effect of anti-adhesion and drag reduction is improved by 18.81 %.

Ab initio calculations of anomalous seniority breaking in the πg9/2 shell for the N = 50 isotones

We performed ab initio valence-space in-medium similarity renormalization group (VS-IMSRG) calculations based on chiral two-nucleon and three-nucleon interactions to investigate the anomalous seniority breaking in the neutron number N=50 isotones: 92Mo, 94Ru, 96Pd, and 98Cd. Our calculations well reproduced the measured low-lying spectra and electromagnetic E2 transitions in these nuclei, supporting partial seniority conservation in the first πg9/2 shell. Recent experiments have revealed that, compared to the symmetric patterns predicted under the conserved seniority symmetry, the 41+→21+E2 transition strength in 94Ru is significantly enhanced and that in 96Pd is suppressed. In contrast, the 61+→41+ and 81+→61+ transitions exhibit the opposite trend. We found that this anomalous asymmetry is sensitive to subtle seniority breaking effects, providing a stringent test for state-of-the-art nucleon-nucleon interactions and nuclear models. We analyzed the anomalous asymmetry using VS-IMSRG calculations across various valence spaces. Our ab initio results suggest that core excitations of both proton and neutron across the Z=50 shell are ascribed to the observed anomalous seniority breaking in the N=50 isotones.