Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. Subjects: Computer Science >> Other Disciplines of Computer Science submitted time 2024-05-14
Abstract： In his 1950 paper cite{Turing1950}, Turing proposed the notion of a thinking machine, namely a machine that can think. But a thinking machine has to follow a certain law of physics, provided it is realized physically. In this paper, we show that Turing’s thinking machine necessrily obeys ’t Hooft’s principle of superposition of states, which was presented by ’t Hooft cite{Hooft2016} in 2016 beyond the usual one as described by Dirac cite{Dirac1958} in the conventional quantum mechanics. Precisely, Turing’s thinking machine must be a quantum machine, while ’t Hooft’s principle characterizes its thinking behavior in a probabilistic way.
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Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2024-04-22
Abstract： The possibility of Lorentz symmetry breaking has been discussed in many models of quantum gravity. In this paper we followed the Lorentz violation model in Ref. 14 to discuss the Doppler frequency shift of photons and the Compton scattering process between photons and electrons, pointing out that following the idea in Ref. 14 we have to modify the usual quantum relation of photons involved in the Doppler effect. But due to the current limited information and knowledge, we couldn’t yet determine the specific expression for the correction coefficient of the quantum relation of photons. However, the phenomenon of spontaneous radiation in a cyclotron maser give us an opportunity to see what the expression for this correction coefficient might look like, as the phenomenon of spontaneous radiation in a cyclotron maser can be explained by the Doppler effect of virtual photons and the Compton scattering process between virtual photons and electrons (or other particles). Therefore, under some restrictive conditions, we construct a very concise expression for this correction coefficient by discussing different cases. And then we used this expression to analyze the wavelength of radiation in the cyclotron maser, which tends to be a limited value at v→c, rather than to be 0 as predicted by the Lorentz model.And we also discussed the inverse Compton scattering phenomenon and found that there is a limit to the maximum
energy that can be obtained by photons in the collision between ultra-high energy particles and low-energy photons, which conclusion is also very different from that obtained from the Lorentz model, in which the energy that can be obtained by the photon tends to be infinite as the velocity of particle is close to c. This paper still inherits the idea in Ref. 14 that the energy and momentum of particles (i.e., any particles, including photons) cannot be infinite, otherwise it will
make some physical scenarios meaningless, and this view is also from the idea in some quantum gravity models. When the parameter Q characterizing the degree of deviation from the Lorentz model is equal to 0, all the results and conclusions in this paper will return to the case as in the Lorentz model, so this paper also provides us with a possible experimental scheme to determine the value of Q in Ref. 14 , although it still requires extremely high experimental energy.
Peer Review Status:Awaiting Review
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2024-04-10
Abstract： Artificial Neural Network (ANN) has become a powerful tool in the field of scientific research with its powerful information encapsulation ability and convenient variational optimization method. In particular, there have been many recent advances in computational physics to solve variational problems. Deep neural network (DNN) is used to represent the wave function to solve quantum many-body problems using variational optimization. In this work we used a new Physics-Informed Neural Network (PINN) to represent the Cumulative Distribution Function (CDF) of some classical problems in quantum mechanics and to obtain their ground state wave function and ground state energy through the CDF. By benchmarking against the exact solution, the error of the results can be controlled at a very low level. This new network architecture and optimization method can provide a new choice for solving quantum many- body problems.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2024-03-09
Abstract： There is a U(4’) times U(4)-bundle on four-dimensional square root Lorentz manifold. Then a Pati-Salam model in curved space-time (Lagrangian) and a gravity theory (Lagrangian) are constructed on square root Lorentz manifold based on self-parallel transportation principle. An explicit formulation of Sheaf quantization on this square root Lorentz manifold is shown. Sheaf quantization is based on superposition principle and construct a linear Sheaf space in curved space-time. The transition amplitude in path integral quantization is given which is consistent with Sheaf quantization. All particles and fields in Standard Model (SM) of particle physics and Einstein gravity are found in square root metric and the connections of bundle. The interactions between particles/fields are described by Lagrangian explicitly. There are few new physics in this model. The gravity theory is Einstein-Cartan kind with torsion. There are new particles, right handed neutrinos, dark photon, Fiona, X^{ pm C} and Y^0,Y^1,Y^2,Y_*^1,Y_*^2.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2024-02-27
Abstract： This paper conducts electromagnetic induction experiments involving relative motion of coils and magnets, and analyses multiple cases of electromagnetic interactions. Both experimental results and analysis indicate the correctness of Weber’s hypothesis on the unipolar induction problem. Moreover, it is demonstrated that compared to the concept of magnetic field, the concept of magnetic field line is equally useful and important in explaining electromagnetic interactions.
Peer Review Status:Awaiting Review
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract： With the deepening of interdisciplinary integration,the finite element method has been widely used in biomechanics study of the musculoskeletal system of lower limbs due to its advantages of high efficiency,accuracy and convenience,and has promoted the development of clinical personalized therapy,rehabilitation technical aids,smart wearable and other fields.Therefore,the method has broad prospects.With Web of Science,PubMed and CNKI databases as data sources,“finite element and(lower limb or lower extremity or leg)” as English key words and “finite element,lower limb” as Chinese key words were used to retrieve finite element studies focusing on lower limbs from 2018 to 2022.This study systematically formulated the clinical application of finite element method in fracture prediction and risk assessment,fracture fixation method and mechanical analysis of fixed instruments,and joint replacement evaluation.The study and application of finite element method in bone stress analysis,mechanical analysis of rehabilitation technical aids and mechanical analysis of lower extremity-fabric model were explored.The results show that the finite element method can establish the lower limbs model in accordance with the biomechanical theory,simulate various working conditions,reflect the stress and strain of the internal structure of human tissues,promote the in-depth study of clinical medicine personalized treatment,and promote the intelligent development of lower limb rehabilitation technical aids and smart wearable product.Future research should focus on improving the accuracy of finite element calculation,combining high-precision measurement technology,multi-body dynamic musculoskeletal model with finite element method,and establishing human-fabric finite element model so as to further promote the breadth and depth of biomechanical studies on lower limb musculoskeletal system.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract：
According to the classic Flügge shell theory,the calculation method of the homogenization conversion of the physical properties and mechanical behavior similarity of functionally graded materials(FGM)and homogeneous materials is used to study the prediction method of the critical pressure of FGM cylindrical shells under hydrostatic pressure.Considering the influence of the fluid,the wave method is used to derive the vibration equation of the underwater FGM cylindrical shell coupled system,and the Newton iteration method is used to find the natural frequency of the FGM cylindrical shell under hydrostatic pressure; According to the linear correlation between the critical load and the load level when the natural frequency is zero,the critical pressure of the FGM cylindrical shell under hydrostatic pressure is predicted and analyzed by the fitting curve method and the formula method after homogenization conversion,and the influence of various parameters of FGM cylindrical shell on the critical pressure of FGM cylindrical shell under hydrostatic pressure is discussed.The results show that the total value of the material elastic modulus E of the FGM cylindrical shell,geometric dimensions h/R and L/R of the FGM cylindrical shell,and changes in different boundary conditions have a greater impact on the critical pressure.Through the comparative analysis of multiple sets of calculation examples,the correctness and effectiveness of the method in this paper are verified,and the prediction accuracy is high and the calculation amount is small,which can provide a new exploration approach for the analysis of the mechanical behavior of non-uniform structures.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract： This paper validates the ability of three dimensional rigid-body-spring-method(3D RBSM)to simulate the shear failure behaviors of large crossse-ctional RC deep beams with and without stirrups.The numerical results prove that 3D RBSM not only can accurately reproduce the diagonal cracking load,normalized shear strength and the reinforcing effect of stirrups but also can simulate the deformation process and shear failure mode for RC deep beam.Compared with finite element analysis(FEA),3D RBSM has evident advantages:significantly improve the accuracy of normalized shear strength calculation,visualize the dispersed distribution of crack and quantitatively estimate crack width; has the capacity of reproducing the post-peak softening behavior.Therefore,it is concluded that 3D RBSM can be used to simulate the shear performance of large crossse-ctional RC deep beam,clarify the mechanism of size effect for shear strength and improve the shear design for large size RC members.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract： Algorithms with numerical dissipation have attracted much attention because of their ability to effectively filter the effects of false high-frequency responses.Based on the Z-transform of discrete control theory,a class of explicit time-history integral algorithm with numerical dissipation for structural dynamics is proposed.The speed and displacement recursion of CR algorithm are used in this new algorithm,which can meet the zero amplitude decay rate.It is unconditionally stable for linear systems and nonlinear stiffness softening systems,and is conditionally stable for stiffness hardening systems.A single parameter ρ is used to control the existence of numerical dissipation and the size of the dissipation capacity.Theoretical analysis of amplitude attenuation and period extension shows that the accuracy and nonlinear stability interval of the algorithm can be adjusted by the coefficient a,and the coefficient value is given when the accuracy is optimal.And the new algorithm reduces to CR method for specific coefficients.Numerical examples of linear and nonlinear systems show that the new algorithm has good accuracy,stability and numerical dissipation,indicating that the new algorithm is correct and effective.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract： “Wind-induced snow drift” may cause the collapse of buildings,thus affecting people’s property and personal safety.Therefore,the combined effect of wind and snow can not be ignored in the design of long-span structures.This paper is based on the mixture multiphase flow model and k-kl-ω model,using Euler-Euler method.Four kinds of large span hyperbolic roof structures with projection shapes of square,rectangular,circular and elliptical are selected as the model structures.When the wind direction angle is different,the curve of wind-induced snow pressure coefficient and snow distribution coefficient cloud map on the roof surface of the four structures under the combined action of wind and snow are studied.In addition,they are compared and analyzed.The results show that the wind-induced snow pressure coefficient of four roof structures under wind-induced snow drift is larger than that under single wind.The position of the maximum wind-induced snow pressure coefficient on the surface of the four roof structures is different.When the wind direction angle is different,the order of pressure on the roof surface from large to small is rectangular,elliptical,square and circular roof.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract： Considering that the mechanical properties of the compression zone of plastic steel fiber reinforced lightweight aggregate concrete beams in the mid span are the key factor in improving the overall bending mechanical properties of the beams,six compression zone reinforced plastic steel fiber reinforced lightweight aggregate concrete beams were tested under bending loading using three strengthening methods:steel fiber reinforcement,spiral stirrups,and rectangular stirrups as the basic parameters for the local compression zone in the mid span.The effects of reinforcement methods,longitudinal reinforcement ratio,and concrete strength in the reinforcement zone on the flexural mechanical properties of plastic steel fiber reinforced lightweight aggregate concrete reinforced beams were discussed.The results show that plastic steel fibers have the effect of toughening,cracking resistance,and delaying crack development on lightweight aggregate concrete beams,and the phenomenon of super-reinforced failure of plastic steel fiber lightweight aggregate concrete beams has been significantly improved after mid span strengthening in the compression zone.The bearing capacity and ductility of the specimens reinforced with spiral stirrups in the mid span of the compression zone are the best,while the ultimate compressive strain of the concrete reinforced with steel fibers in the mid span of the compression zone is the highest,while the ductility of the concrete specimens reinforced with rectangular stirrups in the mid span of the compression zone is the worst.By increasing the longitudinal reinforcement ratio,the bearing capacity of the specimens strengthened with steel fibers in the mid span of the compression zone has been significantly improved,but the ductility has decreased.By increasing the concrete strength in the strengthened zone,the bearing capacity of the specimens strengthened with steel fibers in the mid span of the compression zone has been improved to a certain extent,with little change in ductility.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract：
From a mesoscopic point of view,lightweight aggregate concrete(LWAC)is regarded as a composite material composed of light coarse aggregate(LCA),mortar matrix,and the interface transition zone(ITZ)between aggregates and mortar matrix.Meso-scale numerical model of LWAC composed of lightweight aggregates with three different equivalent dimensions was established and the behavior of LWAC under uniaxial compression load using plastic damage constitutive law was carried out.The uniaxial compression behavior in the form of damage distribution and the corresponding macro stress-strain relationship were investigated numerically.The effects of different light coarse aggregate content,apparent density,maximum size and random distribution on the damage distribution and macro stress-strain relationship were studied.Results show that the compression failure of LWAC causes the fracture of LCA.The content and apparent density of LCA have a great impact on the mechanical properties of LWAC.The maximum size of LCA has a mild effect on the uniaxial compressive strength of LWAC.The random distribution of LCA affects the nonlinear section of the uniaxial compressive stress-strain curve of LWAC and has obvious influence on the damage distribution.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract： The susceptibility of shipborne helicopter to external maneuvering load fluctuation leads to deviation of shaft angle connecting horizontal drive shaft and oblique tail shaft,which leads to excessive vibration of tail drive system,and even catastrophic accidents such as fracture of tail drive shaft in serious cases.This paper first deduces the vibration equation of the tail drive system containing shaft angle parameter,gets the relationship between shaft angle deviation and meshing stiffness,and explores the internal connection between the deviation and tail inclined shaft vibration amplitude.Taking one type of helicopter tail slanting transmission system as the research object,this paper sets up the tail drive system dynamics model and reveals the law of tail shaft angle parameters’ influence on inclined shaft vibration characteristics:The vibration response trend of tail-drive systems with different design angles is basically the same when the shaft angle deviation occurs,and the vibration amplitude of tail-inclined shaft increases with the increase of design angle.When the shaft angle deviation occurs in the range of 0-2 degrees,the vibration amplitude of the tail-inclined axis increases first and then decreases.When the deviation is about 1.5 degrees,the amplitude of the tail-inclined axis reaches the maximum.When the shaft angle deviation is the same,the vibration amplitude at the middle reducer on the aft oblique shaft is 3.6 times that at the aft reducer.The research results can provide reference for dynamic design and vibration fault analysis of helicopter tail transmission system.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract： Most of the research on cantilever beam is based on deterministic analysis or the assumed Gaussian excitation,non-Gaussian excitation is rarely involved.Stochastic responses of cantilever beam with lumped mass subjected to non-Gaussian random excitation are studied in this paper.Motion equation of the structure is established by the Lagrange’s equation which considers curvature nonlinearity,approximate transient solutions of responses of structure are obtained by exponential polynomial closure(EPC)method.Effects of average arrival rate,excitation intensity and lumped mass on the structural response are analyzed.Meanwhile,the influence of nonlinear structural parameters on structural response under non-stationary and non-Gaussian excitation is also analyzed.Numerical results show that results obtained by the EPC method agree well with simulation solution.With the increase of the average arrival rate,the probabi-lity density function curve of structural response presents centralization.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract： Aiming at the impact of wind and sand on tempered laminated glass in engineering materials,using the double Fourier series,the deflection function of a rectangular elastic sandwich sheet with four edges simply supported under impact load is constructed.The coefficient of the deflection function is solved based on the integral transformation method.The stress and strain functions of the rectangular thin plate of laminated glass under the condition of simple support on four sides were obtained,and its distribution law was calculated by programming to analyze the dynamic characteristics of the laminated glass under impact.The results show that the impact force and displacement response first increase and then decrease at different impact heights,and the displacement response is divided into contact loading period,contact unloading period,and disengagement period due to the impact inertia effect.In the glass,the stress wave is symmetrical propagation and continuous attenuation cause the displacement field,strain field,and stress field to be symmetrically distributed,and the impact load has the greatest impact on the impact point; the lower surface of the impact point area of the laminated glass sheet is stretched to cause tensile failure,and the boundary area is compressed to cause compression failure,but the opposite is true for the upper surface.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract： The operational deflection shapes(ODS)under high frequency dynamic response analysis method was proposed to detect the debonding welding defects in lattice sandwich structure.The ODS contains the overall dynamic response characteristics of the structure,especially the local vibration information of the damaged area under high-frequency excitation.First,the characteristic frequency of the damaged local area is calculated by simulation,and the appropriate high-frequency and wide-band excitation damage structure is selected.Then,the PZT is combined with a scanning laser vibrometer to detect the dynamic response of the damaged structure under high-frequency steady-state signal excitation,and comprehensively consider the ODS at multiple frequencies in the frequency band to directly locate the damage.Both simulation and experiment verify the effectiveness of the method in identifying damage.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract： The suspended cable is a typical flexible mechanical system with large span and low damping.The system has quadratic and cubic nonlinearities,which leads to it including rich nonlinear behaviors,especially the coupling resonance between different modes.In addition,due to the influence of temperature,solar radiation,wind and other factors,the surrounding temperature field of cable changes obviously,and linear and nonlinear vibration characteristics of suspension cables are sensitive to temperature changes.In this paper,the suspension cable simultaneously has the primary resonance and the three-to-one internal resonance as an example,the single degree of freedom model which ignores modal coupling was extended to multi-degree of freedom model.The average equations of polar and Lagrange coordinates are obtained by multiscale method.Based on the various response curves of the system,the modal coupling vibration characteristics of the suspension cable under different temperature are discussed in detail.The numerical example results show that:when the temperature drops(rises),the suspension cables with larger(smaller)Irvine parameters are prone to the three-to-one internal resonance.In the region of internal resonance,the influence of temperature changes on the response amplitude of low-order mode is greater than that of high-order mode.The sensitivity of Hopf bifurcation to temperature change is higher than that of saddle bifurcation.In the resonance region,the periodic motion of the system is sensitive to temperature changes,and the periodic motion of the system may become aperiodic motion when the temperature changes.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract： Taking the first phase of the integrated pipe gallery in Jishou City as the background,based on the prototype observation test during the backfilling process of the prefabricated pipe gallery and the “life and death unit” function in ABAQUS,a three-dimensional dynamic numerical model of the pipe gallery backfilling process was established and the construction was studied.Force and deformation characteristics of fabricated pipe gallery during backfilling.The results show that the stress and deformation of the pipe gallery structure in the backfilling stage show a “two-stage” change.When the pipe gallery cover soil depth is less than 2 m,the pipe gallery structure as a whole bears less force and deformation.When the pipe gallery cover soil depth is greater than 2 m,the pipe gallery structure is stressed.The deformation is basically linear elastic growth; the longitudinal stress and deformation of the pipe gallery structure at the three different cross-sections of the precast section,the cast-in-situ section,the precast section and the cast-in-situ section caused by the covering soil load is generally greater than the horizontal deformation.The force and deformation are obvious at the mid-span position of the bottom plate; in terms of the difference in section deformation,the transverse force and deformation at the overlap of the precast section and the cast-in-situ section are obvious.Considering the stress and deformation characteristics of the pipe gallery during the construction process,when designing the pipe gallery structure,special measures should be taken for the mid-span,precast section sockets of the top and bottom plates of the pipe gallery structure,especially the overlap between the precast section and the cast-in-place section.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract： The buckling and post-buckling behaviors of an elastic rod subjected to both axial force and transverse cylindrical constraints are studied.The axial critical forces of sinusoidal buckling and spiral buckling of slender rod are analyzed by finite element simulation,and the discrimination method for critical point of sinusoidal and spiral buckling is proposed,which is verified by comparison with literature results.The influence of slenderness ratio and boundary conditions on the critical force is also investigated.The results show that the critical forces of sinusoidal buckling and spiral buckling increase with the decrease of the slenderness ratio of the rod.In a certain range of rod length,the influence of end constraint conditions on critical load and buckling mode is not negligible.While the influence of boundary conditions on the critical load can be ignored as the length of the rod is long enough.
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc. submitted time 2023-11-10 Cooperative journals: 《应用力学学报》
Abstract：
The damage of concrete is affected by its internal defects.In order to study the influence of the porosity content on the mechanical properties of RCC and discuss the mechanical properties of roller compacted concrete and size effect as the rule of variation of porosity,the pore of roller compacted concrete is simulated by using pore method for mechanical properties test.We analyze three-dimensional C20 roller compacted concrete specimen under the condition of four different porosity of compressive strength and splitting tensile strength of the changes.The results show that at the same size,the compressive strength and splitting strength of C20 RCC decrease gradually with the increase of porosity,and the increase of pore content has a negative effect on the strength.RCC has an obvious size effect:with the increase of porosity,the size effect of RCC strength becomes more significant.
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