In a fractal zeta universe of bifurcated, ripped spacetime, the Millikan experiment, the quantum Hall effect, atmospheric clouds and universe clouds are shown to be self-similar with mass ratio of about 1020. Chaotic ...In a fractal zeta universe of bifurcated, ripped spacetime, the Millikan experiment, the quantum Hall effect, atmospheric clouds and universe clouds are shown to be self-similar with mass ratio of about 1020. Chaotic one-dimensional period-doublings as iterated hyperelliptic-elliptic curves are used to explain n-dim Kepler- and Coulomb singularities. The cosmic microwave background and cosmic rays are explained as bifurcated, ripped spacetime tensile forces. First iterated binary tree cloud cycles are related to emissions 1…1000 GHz. An interaction-independent universal vacuum density allows to predict large area correlated cosmic rays in quantum Hall experiments which would generate local nuclear disintegration stars, enhanced damage of layers and enhanced air ionization. A self-similarity between conductivity plateau and atmospheric clouds is extended to correlations in atmospheric layer, global temperature and climate.展开更多
Micro-grinding has been widely used in aerospace and other industry.However,the small diameter of the micro-grinding tool has limited its machining performance and efficiency.In order to solve the above problems,micro...Micro-grinding has been widely used in aerospace and other industry.However,the small diameter of the micro-grinding tool has limited its machining performance and efficiency.In order to solve the above problems,micro-structure has been applied on the micro-grinding tool.A morphology modeling has been established in this study to characterize the surface of microstructured micro-grinding tool,and the grinding performance of micro-structured micro-grinding tool has been analyzed through undeformed chip thickness,abrasive edge width,and effective distance between abrasives.Then deviation analysis,path optimization and parameter optimization of microchannel array precision grinding have been finished to improve processing quality and efficiency,and the deflection angle has the most obvious effects on the rectangular slot depth,micro-structured micro-grinding tool could reduce 10%surface roughness and 20%grinding force compared to original micro-grinding tool.Finally,the microchannel array has been machined with a size deviation of 2μm and surface roughness of 0.2μm.展开更多
Gravitational collapse and bubble evolution in the asymptotic Friedmann–Lemaître–Robertson–Walker(FLRW)Universe is an intriguing and intricate problem.We systematically analyze the dynamics of contact Schwarzs...Gravitational collapse and bubble evolution in the asymptotic Friedmann–Lemaître–Robertson–Walker(FLRW)Universe is an intriguing and intricate problem.We systematically analyze the dynamics of contact Schwarzschild–FLRW(McVittie)spacetimes,focusing on their general junction conditions and introducing a novel function to simplify the extrinsic curvature and surface stress–energy tensor.Both static and dynamic scenarios are explored,including special cases such as Schwarzschild,FLRW,and Einstein–Straus configurations using our general framework.Numerical calculations further investigate the evolution of concentric McVittie spacetimes under various initial conditions,incorporatingΛ-CDM cosmological models to better reflect realistic cosmic backgrounds.These results offer deep insights into the interplay between the McVittie mass parameter,initial peculiar velocity,and the influence of dark energy,providing a unified perspective for understanding gravitational collapse and bubble evolution in cosmology and astrophysics.展开更多
In this work we study gravitational lensing of the wormhole in the Eddington-inspired Born–Infeld(EiBI)spacetime that incorporates with a cosmic string.It is found that the presence of a cosmic string can enhance the...In this work we study gravitational lensing of the wormhole in the Eddington-inspired Born–Infeld(EiBI)spacetime that incorporates with a cosmic string.It is found that the presence of a cosmic string can enhance the light deflection in the strong-field limit,compared to the Ellis–Bronnikov wormhole.The magnification effects of this composite structure could cause some substantial impacts on the angle separation between the first and the rest of the images,and their relative brightness.Furthermore,based on these observables,we model some observable aspects in the strong-and the weak-field limits.The presence of a cosmic string can affect some distinguishable observables compared to the wormhole without cosmic string.This work could deepen our understanding of the spacetime structure of the wormhole in EiBI spacetime with one-dimensional topological defects.展开更多
This research paper seeks to investigate the characteristics of almost Riemann solitons and almost gradient Riemann solitons within the framework of generalized Robertson–Walker(GRW)spacetimes that incorporate imperf...This research paper seeks to investigate the characteristics of almost Riemann solitons and almost gradient Riemann solitons within the framework of generalized Robertson–Walker(GRW)spacetimes that incorporate imperfect fluids.Our study begins by defining specific properties of the potential vector field linked to these solitons.We examine the potential vector field of an almost Riemann soliton on GRW imperfect fluid spacetimes,establishing that it aligns collinearly with a unit timelike torse-forming vector field.This leads us to express the scalar curvature in relation to the structures of soliton and spacetime.Furthermore,we explore the characteristics of an almost gradient Riemann soliton with a potential functionψacross a range of GRW imperfect fluid spacetimes,deriving a formula for the Laplacian ofψ.We also categorize almost Riemann solitons on GRW imperfect fluid spacetimes into three types:shrinking,steady,and expanding,when the potential vector field of the soliton is Killing.We prove that a GRW imperfect fluid spacetime with constant scalar curvature and a Killing vector field admits an almost Riemann soliton.Additionally,we demonstrate that if the potential vector field of the almost Riemann soliton is aν(Ric)-vector,or if the GRW imperfect fluid spacetime is W_2-flat or pseudo-projectively flat,the resulting spacetime is classified as a dark fluid.展开更多
In this paper,we present the second post-Newtonian solution for the quasi-Keplerian motion of a test particle in the regular Simpson–Visser black-bounce spacetime which has a bounce parameter a.The obtained solution ...In this paper,we present the second post-Newtonian solution for the quasi-Keplerian motion of a test particle in the regular Simpson–Visser black-bounce spacetime which has a bounce parameter a.The obtained solution is formulated in terms of orbital energy,angular momentum,and the bounce parameter of the black hole.We explicitly analyze the leading effects of the bounce parameter which has dimensions of length,on the test particle’s orbit,including the periastron advance and orbital period.Then,we apply this model to the precessing motion of OJ 287 and determine the upper limits of the dimensionless bounce parameter as a/m=3.45±0.01,where m is the mass of the regular black hole.Compared with the bound given by the periastron advance of star S2,our bound on a/m is reduced by one order of magnitude,although our upper limit of a still needs further improvement.展开更多
High-performance 24CrNiMo steel was fabricated using Laser Powder Bed Fusion (LPBF). Subsequent quenching treatment was applied and the influence of quenching temperatures on micro-structure evolution and properties w...High-performance 24CrNiMo steel was fabricated using Laser Powder Bed Fusion (LPBF). Subsequent quenching treatment was applied and the influence of quenching temperatures on micro-structure evolution and properties was systematically characterised and analysed. The micro-structure of the as-built steel consisted of two parts. The first part comprised martensite with twins combined with ω-Fe nano-particles, and the second part consisted of lower bainite in the molten pool, as well as upper bainite, granular bainite and tempered martensite in the heat-affected zone. With the quenching temperatures varying from 800℃ to 950℃, the micro-structure gradually transformed from acicular ferrite + martensite to tempered martensite +θ-Fe3C carbides, and the grain size exhibited noticeable growth. Moreover, quenching treatments could eliminate the anisotropy and inhomogeneity of the micro-structure. The rod-shaped nanosized η-Fe2C and θ-Fe3C precipitates were clearly observed, which were converted from ω-Fe and distributed at multiple angles in the lath. The size and number of nano-precipitates, triggered by the high self-tempering degree of martensite, gradually increased. The relationships among grain size, the twins, dislocation density and nano-precipitation and the dramatically improved performance of quenched samples were analysed using strengthening mechanisms. After quenching at 850℃, the as-built 24CrNiMo steel attained ultra-high mechanical properties including hardness, Ultimate Tensile Strength (UTS), Elongation (El) and impact energy with values of 480.9 HV_(1), 1611.4 MPa, 9.8% and 42.8 J, respectively. Meanwhile, both the wear and thermal fatigue resistance increased by approximately 40%. This study demonstrated that LPBF-fabricated 24CrNiMo steel, with matching good performances, can be achieved using a subsequent one-step quenching process.展开更多
Based on the Many Worlds Interpretation,I describe reality as a multilayer spacetime,where parallel layers play the role of alternative timelines.I link physics to ethics,arguing that one’s moral choices shape one’s...Based on the Many Worlds Interpretation,I describe reality as a multilayer spacetime,where parallel layers play the role of alternative timelines.I link physics to ethics,arguing that one’s moral choices shape one’s course in the multiverse.I consider one’s ethical decisions as decoherence events,leading to movement between alternative timelines,lighter(higher)or heavier(lower)realities.Sometimes in one’s curvilinear path in spacetime,one can even experience falling toward lower layers,slipping through wormholes.This theory supports free will and the simulation hypothesis.With this background,I explore the idea that a new theory of gravity might open new possibilities to shape matter and change our worldview through the invention of new technology,transforming information into waves and then into solid matter,paving the way for a new Multiverse Aeon for humanity.展开更多
In order to investigate a gradient nano/micro-structured surface layer on pure copper produced by severe plasticity roller burnishing （SPRB） and grain refinement mechanism, the microstructure characteristics and mat...In order to investigate a gradient nano/micro-structured surface layer on pure copper produced by severe plasticity roller burnishing （SPRB） and grain refinement mechanism, the microstructure characteristics and material properties of sample at various depths from the topmost surface were investigated by SEM, TEM, XRD, OM etc. The experimental results show that the gradient nano/micro-structure was introduced into the surface layer of over 100μm in thickness. The remarkable increase in hardness near the topmost surface was mainly attributed to the reduced grain size. The equiaxed nano-sized grains were in random orientation and the most of their boundaries were low-angle grain boundaries （LAGBs）. The coarse grains are refined into the few micro-sized grains by dislocation activities;deformation twinning was found to be the primary form for the formation of submicron grains;the formation of nanostructure was dominated by dislocation activities accompanied with rotation of grains in local region.展开更多
The present paper is basically a synthesis resulting from incorporating Kerr spinning black hole geometry into E-infinity topology, then letting the result bares on the vacuum zero point Casimir effect as well as the ...The present paper is basically a synthesis resulting from incorporating Kerr spinning black hole geometry into E-infinity topology, then letting the result bares on the vacuum zero point Casimir effect as well as the cosmic dark energy and dark matter density. In E-infinity theory a quantum particle is represented by a Hausdorff dimension Φ where Φ =2/(√5+1) . The quantum wave on the other hand is represented by Φ2 . To be wave and a particle simultaneously intersection theory leads us to?(Φ) (Φ)2= Φ3 which will be shown here to be twice the value of the famous Casimir force of the vacuum for a massless scalar field. Thus in the present work a basically topological interpretation of the Casimir effect is given as a natural intrinsic property of the geometrical topological structure of the quantum-Cantorian micro spacetime. This new interpretation compliments the earlier conventional interpretation as vacuum fluctuation or as a Schwinger source and links the Casimir energy to the so called missing dark energy density of the cosmos. From the view point of the present work Casimir pressure is a local effect acting on the Casimir plates constituting the local boundary condition while dark energy is nothing but the global combined effect of infinitely many quantum waves acting on the Möbius-like boundary of the holographic boundary of the entire universe. Since this higher dimensional Möbius-like boundary is one sided, there is no outside to balance the internal collective Casimir pressure which then manifests itself as the force behind cosmic expansion, that is to say, dark energy. Thus analogous to the exact irrational value of ordinary energy density of spacetime E(O)=(Φ5/2) mc2 we now have P (Casimir) = (Φ3/2)(ch/d2) where c is the speed of light, m is the mass, h is the Planck constant and d is the plate separation. In addition the new emerging geometry combined with the topology of E-infinity theory leads directly to identifying dark matter with the quasi matter of the ergosphere. As a direct consequence of this new insight E=mc2 which can be written as E = E (O) + E (D)?where the exact rational approximation is E (O)=mc2/22 is?the ordinary energy density of the cosmos and the exact rational approximation E (D)=mc2/(21/22) is the corresponding dark energy which could be subdivided once more albeit truly approximately into E(D)=mc2/(5/22)?+mc2/(16/22)??where 5 is the Kaluza Klein spacetime dimension, 16 are the bosonic extra dimensions of Heterotic superstrings and 5/22 □?22% is approximately the density of the dark matter-like energy of the ergosphere of the Kerr geometry. As for the actual design of our nano reactor, this is closely related to branching clusters of polymer, frequently called lattice animals. In other words we will have Casimir spheres instead of Casimir plates and these spheres will be basically nano particles modelling lattice animals. Here D=?4 will be regarded as spacetime dimensionality while D=6 of percolations are the compactified super string dimensions and D=8 is the dimension of a corresponding super space.展开更多
The paper presents a very simple and straight forward yet pure mathematical derivation of the structure of actual spacetime from quantum set theory. This is achieved by utilizing elements of the topological theory of ...The paper presents a very simple and straight forward yet pure mathematical derivation of the structure of actual spacetime from quantum set theory. This is achieved by utilizing elements of the topological theory of cobordism and the Menger-Urysohn dimensional theory in conjunction with von Neumann-Connes dimensional function of Klein-Penrose modular holographic boundary of the E8E8 exceptional Lie group bulk of our universe. The final result is a lucid sharp mental picture, namely that the quantum wave is an empty set representing the surface, i.e. boundary of the zero set quantum particle and in turn quantum spacetime is simply the boundary or the surface of the quantum wave empty set. The essential difference of the quantum wave and quantum spacetime is that the wave is a simple empty set while spacetime is a multi-fractal type of infinitely many empty sets with increasing degrees of emptiness.展开更多
We provide a new class of interior solution of a(2+1)-dimensional anisotropic star in Finch and Skea spacetime corresponding to the BTZ black hole. We develop the model by considering the MIT bag model EOS and a parti...We provide a new class of interior solution of a(2+1)-dimensional anisotropic star in Finch and Skea spacetime corresponding to the BTZ black hole. We develop the model by considering the MIT bag model EOS and a particular ansatz for the metric function grrproposed by Finch and Skea [M.R. Finch and J.E.F. Skea, Class. Quantum.Grav. 6(1989) 467]. Our model is free from central singularity and satisfies all the physical requirements for the acceptability of the model.展开更多
Some properties related to the NUT-Taub-like spacetime, such as the surface of infinite red-shift, horizon, singularity and the area of the NUT-Taub-like black hole are discussed. Furthermore, the geodesics in the NUT...Some properties related to the NUT-Taub-like spacetime, such as the surface of infinite red-shift, horizon, singularity and the area of the NUT-Taub-like black hole are discussed. Furthermore, the geodesics in the NUT-Taub-like spacetime are obtained in some special cases. Specifically, the circular orbits for a massive particle are derived, which can reduce to the cases of the Schwarzschild spacetime and the NUT-Taub spacetime when m^＊ = 0 and m^＊ 〈〈 M, respectively.展开更多
Nowadays,the superior detection performance of semiconductor neutron detectors is a challenging task.In this paper,we deal with a novel GaN micro-structured neutron detector(GaN-MSND)and compare three different method...Nowadays,the superior detection performance of semiconductor neutron detectors is a challenging task.In this paper,we deal with a novel GaN micro-structured neutron detector(GaN-MSND)and compare three different methods such as the method of modulating the trench depth,the method of introducing dielectric layer and p-type inversion region to improve the width of depletion region(W).It is observed that the intensity of electric field can be modulated by scaling the trench depth.On the other hand,the electron blocking region is formed in the detector enveloped with a dielectric layer.Furthermore,the introducing of p-type inversion region produces new p/n junction,which not only promotes the further expansion of the depletion region but also reduces the intensity of electric field produced by main junction.It can be realized that all these methods can considerably enhance the working voltage as well as W.Of them,the improvement on W of GaN-MSND with the p-type inversion region is the most significant and the value of W could reach 12.8μm when the carrier concentration of p-type inversion region is 10^17 cm^-3.Consequently,the value of W is observed to improve 200%for the designed GaN-MSND as compared with that without additional design.This work ensures to the researchers and scientific community the fabrication of GaN-MSND having superior detection limit in the field of intense radiation.展开更多
We use a dual Einstein-Kaluza spacetime to calculate the exact energy density of dark energy and dark matter using a novel topological computation method. Starting from the said spacetime and ‘tHooft’s topological r...We use a dual Einstein-Kaluza spacetime to calculate the exact energy density of dark energy and dark matter using a novel topological computation method. Starting from the said spacetime and ‘tHooft’s topological renormalon as well as the corresponding symmetry group, we show how the zero set quantum particle and the empty set quantum wave interact with the vacuum and give rise to pure dark energy and pure dark matter all along with ordinary energy density of the cosmos. The consistency of the exact calculation and the accurate observations attests to the reality of ‘tHooft’s renormalon dark matter, pure dark energy and accelerated cosmic expansion.展开更多
In this paper,we report the study of the process of fabricating a multi-layermetal micro-structure using UV-LIGA overlay technology,includingmask fabrication,substrate treatment,and UV-LIGA overlay processes.To solve ...In this paper,we report the study of the process of fabricating a multi-layermetal micro-structure using UV-LIGA overlay technology,includingmask fabrication,substrate treatment,and UV-LIGA overlay processes.To solve the process problems in the masking procedure,the swelling problemof the first layer of SU-8 thick photoresist was studied experimentally.The 5μmline-width compensation and closed 20μmand 30μmisolation strips were designed and fabricated around the micro-structure pattern.The pore problemin the Ni micro-electroforming layer was analyzed and the electroforming parameters were improved.The pH value of the electroforming solution should be controlled between 3.8 and 4.4 and the current density should be below 3 A/dm^2.To solve the problems of high inner stress and incomplete development of the micro-cylinder hole array with a diameter of 30μm,the lithography process was optimized.The pre-baking temperature was increased via gradient heating and rose every 5℃ from 65℃ to 85℃ and then remained at 85℃ for 50 min–1 h.In addition,the full contact exposure was used.Finally,a multi-layer metal micro-structure with high precision and good quality of microelectroforming layer was fabricated using UV-LIGA overlay technology.展开更多
A low-power CO_2 laser is used to deposit Fe powder and mixture of Fe andcarbon powder on substrates respectively, and the macro and micro-structure of the formed samplesare investigated. It is demonstrated that most ...A low-power CO_2 laser is used to deposit Fe powder and mixture of Fe andcarbon powder on substrates respectively, and the macro and micro-structure of the formed samplesare investigated. It is demonstrated that most grains of these samples are equi-axed. This isderived from the high nucleation velocity in the shallow melt pool besides rapid solidification ofthe liquid-state alloy or metal. Bainitic structure, combination of pearlite and ferrite structureand ferrite structure are seen respectively in the samples involving various amounts of carbon owingto no martensitic transformation in these small samples.展开更多
Looped light in a recent sophisticated real three-slit experiment is interpreted as a strong justification of the old theoretical Peano-Hilbert spacetime model of Ord and El Naschie. This in turn entails the existence...Looped light in a recent sophisticated real three-slit experiment is interpreted as a strong justification of the old theoretical Peano-Hilbert spacetime model of Ord and El Naschie. This in turn entails the existence of extra fractal dimensions and consequently of real dark energy density in full agreement with previous analysis as well as accurate measurements and observations of COBE, WMAP, and the type 1a supernova.展开更多
Abstract： This paper concerns space-like submanifolds in a pseudo-Riemannianspace-time Sp^m＋p∪→Ep^m＋p＋1 （P ≥ 1）, and proves that connected compact maximalsuace-like submanifolds in a pseudo-Riemannian spaceti...Abstract： This paper concerns space-like submanifolds in a pseudo-Riemannianspace-time Sp^m＋p∪→Ep^m＋p＋1 （P ≥ 1）, and proves that connected compact maximalsuace-like submanifolds in a pseudo-Riemannian spacetime Sp^m＋p∪→Ep^m＋p＋1 （P ≥ 1） must be totally umbilical, and also totally geodesic. Particularly, when p = 1, our result is just Montiel＇s in case of H = 0.展开更多
To obtain the form error of micro-structured surfaces robustly and accurately, a form er- ror evaluation method was developed based on the real coded genetic algorithm （RCGA）. The meth- od employed the average squar...To obtain the form error of micro-structured surfaces robustly and accurately, a form er- ror evaluation method was developed based on the real coded genetic algorithm （RCGA）. The meth- od employed the average squared distance as the matching criterion. The point to surface distance was achieved by use of iterative method and the modeling of RCGA for the surface matching was also presented in detail. Parameter selection for RCGA including the crossover rate and population size was discussed. Evaluation results of series simulated surfaces without form error show that this method can achieve the accuracy of root mean square deviation （ Sq ） less than 1 nm and surface pro- file error （ St ） less than 4 nm. Evaluation of the surfaces with different simulated errors illustrates that the proposed method can also robustly obtain the form error with nano-meter precision. The e- valuation of actual measured surfaces further indicates that the proposed method is capable of pre- cisely evaluating micro-structured surfaces.展开更多
文摘In a fractal zeta universe of bifurcated, ripped spacetime, the Millikan experiment, the quantum Hall effect, atmospheric clouds and universe clouds are shown to be self-similar with mass ratio of about 1020. Chaotic one-dimensional period-doublings as iterated hyperelliptic-elliptic curves are used to explain n-dim Kepler- and Coulomb singularities. The cosmic microwave background and cosmic rays are explained as bifurcated, ripped spacetime tensile forces. First iterated binary tree cloud cycles are related to emissions 1…1000 GHz. An interaction-independent universal vacuum density allows to predict large area correlated cosmic rays in quantum Hall experiments which would generate local nuclear disintegration stars, enhanced damage of layers and enhanced air ionization. A self-similarity between conductivity plateau and atmospheric clouds is extended to correlations in atmospheric layer, global temperature and climate.
基金co-supported by the Enterprise Innovation and Development Joint Program of the National Natural Science Foundation of China(No.U20B2032)Open Project Funding of State Key Laboratory for High Performance Tools(GXNGJSKL-2024-08)+1 种基金Open Foundation of the State Key Laboratory of Intelligent Manufacturing Equipment and Technology(IMETKF2023005)Introduced Innovative Scientific Research Team Project of Zhongshan(the tenth batch)(CXTD2023008)。
文摘Micro-grinding has been widely used in aerospace and other industry.However,the small diameter of the micro-grinding tool has limited its machining performance and efficiency.In order to solve the above problems,micro-structure has been applied on the micro-grinding tool.A morphology modeling has been established in this study to characterize the surface of microstructured micro-grinding tool,and the grinding performance of micro-structured micro-grinding tool has been analyzed through undeformed chip thickness,abrasive edge width,and effective distance between abrasives.Then deviation analysis,path optimization and parameter optimization of microchannel array precision grinding have been finished to improve processing quality and efficiency,and the deflection angle has the most obvious effects on the rectangular slot depth,micro-structured micro-grinding tool could reduce 10%surface roughness and 20%grinding force compared to original micro-grinding tool.Finally,the microchannel array has been machined with a size deviation of 2μm and surface roughness of 0.2μm.
基金supported by the National Natural Science Foundation of China(NSFC)under Grant Nos.12275106 and12235019。
文摘Gravitational collapse and bubble evolution in the asymptotic Friedmann–Lemaître–Robertson–Walker(FLRW)Universe is an intriguing and intricate problem.We systematically analyze the dynamics of contact Schwarzschild–FLRW(McVittie)spacetimes,focusing on their general junction conditions and introducing a novel function to simplify the extrinsic curvature and surface stress–energy tensor.Both static and dynamic scenarios are explored,including special cases such as Schwarzschild,FLRW,and Einstein–Straus configurations using our general framework.Numerical calculations further investigate the evolution of concentric McVittie spacetimes under various initial conditions,incorporatingΛ-CDM cosmological models to better reflect realistic cosmic backgrounds.These results offer deep insights into the interplay between the McVittie mass parameter,initial peculiar velocity,and the influence of dark energy,providing a unified perspective for understanding gravitational collapse and bubble evolution in cosmology and astrophysics.
基金supported by the Youth Program of the Natural Science Foundation of Guangxi(Grant No.2021GXNSFBA075049)the Doctor Start-up Foundation of Guangxi University of Science and Technology(Grant No.19Z21)+3 种基金supported by the National Natural Science Foundation of China(Grant No.12165009)supported by the National Natural Science Foundation of China(Grant No.11865005)Hunan Natural Provincial Science Foundation(Grant No.2023JJ30487)supported by the starting Foundation of Guangxi University of Science and Technology(Grant No.24Z17)。
文摘In this work we study gravitational lensing of the wormhole in the Eddington-inspired Born–Infeld(EiBI)spacetime that incorporates with a cosmic string.It is found that the presence of a cosmic string can enhance the light deflection in the strong-field limit,compared to the Ellis–Bronnikov wormhole.The magnification effects of this composite structure could cause some substantial impacts on the angle separation between the first and the rest of the images,and their relative brightness.Furthermore,based on these observables,we model some observable aspects in the strong-and the weak-field limits.The presence of a cosmic string can affect some distinguishable observables compared to the wormhole without cosmic string.This work could deepen our understanding of the spacetime structure of the wormhole in EiBI spacetime with one-dimensional topological defects.
文摘This research paper seeks to investigate the characteristics of almost Riemann solitons and almost gradient Riemann solitons within the framework of generalized Robertson–Walker(GRW)spacetimes that incorporate imperfect fluids.Our study begins by defining specific properties of the potential vector field linked to these solitons.We examine the potential vector field of an almost Riemann soliton on GRW imperfect fluid spacetimes,establishing that it aligns collinearly with a unit timelike torse-forming vector field.This leads us to express the scalar curvature in relation to the structures of soliton and spacetime.Furthermore,we explore the characteristics of an almost gradient Riemann soliton with a potential functionψacross a range of GRW imperfect fluid spacetimes,deriving a formula for the Laplacian ofψ.We also categorize almost Riemann solitons on GRW imperfect fluid spacetimes into three types:shrinking,steady,and expanding,when the potential vector field of the soliton is Killing.We prove that a GRW imperfect fluid spacetime with constant scalar curvature and a Killing vector field admits an almost Riemann soliton.Additionally,we demonstrate that if the potential vector field of the almost Riemann soliton is aν(Ric)-vector,or if the GRW imperfect fluid spacetime is W_2-flat or pseudo-projectively flat,the resulting spacetime is classified as a dark fluid.
基金supported by the National Natural Science Foundation of China(Grant Nos.12303079,12481540180 and 12475057)the support of the postdoctoral program of purple Mountain Observatory,Chinese Academy of Sciences。
文摘In this paper,we present the second post-Newtonian solution for the quasi-Keplerian motion of a test particle in the regular Simpson–Visser black-bounce spacetime which has a bounce parameter a.The obtained solution is formulated in terms of orbital energy,angular momentum,and the bounce parameter of the black hole.We explicitly analyze the leading effects of the bounce parameter which has dimensions of length,on the test particle’s orbit,including the periastron advance and orbital period.Then,we apply this model to the precessing motion of OJ 287 and determine the upper limits of the dimensionless bounce parameter as a/m=3.45±0.01,where m is the mass of the regular black hole.Compared with the bound given by the periastron advance of star S2,our bound on a/m is reduced by one order of magnitude,although our upper limit of a still needs further improvement.
基金co-supported by the National Key Research and Development Program of China (No. 2022YFB4600500)the National Natural Science Foundation of China (No. 52235006)
文摘High-performance 24CrNiMo steel was fabricated using Laser Powder Bed Fusion (LPBF). Subsequent quenching treatment was applied and the influence of quenching temperatures on micro-structure evolution and properties was systematically characterised and analysed. The micro-structure of the as-built steel consisted of two parts. The first part comprised martensite with twins combined with ω-Fe nano-particles, and the second part consisted of lower bainite in the molten pool, as well as upper bainite, granular bainite and tempered martensite in the heat-affected zone. With the quenching temperatures varying from 800℃ to 950℃, the micro-structure gradually transformed from acicular ferrite + martensite to tempered martensite +θ-Fe3C carbides, and the grain size exhibited noticeable growth. Moreover, quenching treatments could eliminate the anisotropy and inhomogeneity of the micro-structure. The rod-shaped nanosized η-Fe2C and θ-Fe3C precipitates were clearly observed, which were converted from ω-Fe and distributed at multiple angles in the lath. The size and number of nano-precipitates, triggered by the high self-tempering degree of martensite, gradually increased. The relationships among grain size, the twins, dislocation density and nano-precipitation and the dramatically improved performance of quenched samples were analysed using strengthening mechanisms. After quenching at 850℃, the as-built 24CrNiMo steel attained ultra-high mechanical properties including hardness, Ultimate Tensile Strength (UTS), Elongation (El) and impact energy with values of 480.9 HV_(1), 1611.4 MPa, 9.8% and 42.8 J, respectively. Meanwhile, both the wear and thermal fatigue resistance increased by approximately 40%. This study demonstrated that LPBF-fabricated 24CrNiMo steel, with matching good performances, can be achieved using a subsequent one-step quenching process.
文摘Based on the Many Worlds Interpretation,I describe reality as a multilayer spacetime,where parallel layers play the role of alternative timelines.I link physics to ethics,arguing that one’s moral choices shape one’s course in the multiverse.I consider one’s ethical decisions as decoherence events,leading to movement between alternative timelines,lighter(higher)or heavier(lower)realities.Sometimes in one’s curvilinear path in spacetime,one can even experience falling toward lower layers,slipping through wormholes.This theory supports free will and the simulation hypothesis.With this background,I explore the idea that a new theory of gravity might open new possibilities to shape matter and change our worldview through the invention of new technology,transforming information into waves and then into solid matter,paving the way for a new Multiverse Aeon for humanity.
基金Project(50975095)supported by the National Natural Science Foundation of ChinaProject(2012ZM0048)supported by the Fundamental Research Funds for the Central Universities,China
文摘In order to investigate a gradient nano/micro-structured surface layer on pure copper produced by severe plasticity roller burnishing （SPRB） and grain refinement mechanism, the microstructure characteristics and material properties of sample at various depths from the topmost surface were investigated by SEM, TEM, XRD, OM etc. The experimental results show that the gradient nano/micro-structure was introduced into the surface layer of over 100μm in thickness. The remarkable increase in hardness near the topmost surface was mainly attributed to the reduced grain size. The equiaxed nano-sized grains were in random orientation and the most of their boundaries were low-angle grain boundaries （LAGBs）. The coarse grains are refined into the few micro-sized grains by dislocation activities;deformation twinning was found to be the primary form for the formation of submicron grains;the formation of nanostructure was dominated by dislocation activities accompanied with rotation of grains in local region.
文摘The present paper is basically a synthesis resulting from incorporating Kerr spinning black hole geometry into E-infinity topology, then letting the result bares on the vacuum zero point Casimir effect as well as the cosmic dark energy and dark matter density. In E-infinity theory a quantum particle is represented by a Hausdorff dimension Φ where Φ =2/(√5+1) . The quantum wave on the other hand is represented by Φ2 . To be wave and a particle simultaneously intersection theory leads us to?(Φ) (Φ)2= Φ3 which will be shown here to be twice the value of the famous Casimir force of the vacuum for a massless scalar field. Thus in the present work a basically topological interpretation of the Casimir effect is given as a natural intrinsic property of the geometrical topological structure of the quantum-Cantorian micro spacetime. This new interpretation compliments the earlier conventional interpretation as vacuum fluctuation or as a Schwinger source and links the Casimir energy to the so called missing dark energy density of the cosmos. From the view point of the present work Casimir pressure is a local effect acting on the Casimir plates constituting the local boundary condition while dark energy is nothing but the global combined effect of infinitely many quantum waves acting on the Möbius-like boundary of the holographic boundary of the entire universe. Since this higher dimensional Möbius-like boundary is one sided, there is no outside to balance the internal collective Casimir pressure which then manifests itself as the force behind cosmic expansion, that is to say, dark energy. Thus analogous to the exact irrational value of ordinary energy density of spacetime E(O)=(Φ5/2) mc2 we now have P (Casimir) = (Φ3/2)(ch/d2) where c is the speed of light, m is the mass, h is the Planck constant and d is the plate separation. In addition the new emerging geometry combined with the topology of E-infinity theory leads directly to identifying dark matter with the quasi matter of the ergosphere. As a direct consequence of this new insight E=mc2 which can be written as E = E (O) + E (D)?where the exact rational approximation is E (O)=mc2/22 is?the ordinary energy density of the cosmos and the exact rational approximation E (D)=mc2/(21/22) is the corresponding dark energy which could be subdivided once more albeit truly approximately into E(D)=mc2/(5/22)?+mc2/(16/22)??where 5 is the Kaluza Klein spacetime dimension, 16 are the bosonic extra dimensions of Heterotic superstrings and 5/22 □?22% is approximately the density of the dark matter-like energy of the ergosphere of the Kerr geometry. As for the actual design of our nano reactor, this is closely related to branching clusters of polymer, frequently called lattice animals. In other words we will have Casimir spheres instead of Casimir plates and these spheres will be basically nano particles modelling lattice animals. Here D=?4 will be regarded as spacetime dimensionality while D=6 of percolations are the compactified super string dimensions and D=8 is the dimension of a corresponding super space.
文摘The paper presents a very simple and straight forward yet pure mathematical derivation of the structure of actual spacetime from quantum set theory. This is achieved by utilizing elements of the topological theory of cobordism and the Menger-Urysohn dimensional theory in conjunction with von Neumann-Connes dimensional function of Klein-Penrose modular holographic boundary of the E8E8 exceptional Lie group bulk of our universe. The final result is a lucid sharp mental picture, namely that the quantum wave is an empty set representing the surface, i.e. boundary of the zero set quantum particle and in turn quantum spacetime is simply the boundary or the surface of the quantum wave empty set. The essential difference of the quantum wave and quantum spacetime is that the wave is a simple empty set while spacetime is a multi-fractal type of infinitely many empty sets with increasing degrees of emptiness.
文摘We provide a new class of interior solution of a(2+1)-dimensional anisotropic star in Finch and Skea spacetime corresponding to the BTZ black hole. We develop the model by considering the MIT bag model EOS and a particular ansatz for the metric function grrproposed by Finch and Skea [M.R. Finch and J.E.F. Skea, Class. Quantum.Grav. 6(1989) 467]. Our model is free from central singularity and satisfies all the physical requirements for the acceptability of the model.
基金Project supported by the National Natural Science Foundation of China （Grant No 10475036）, the Natural Science Foundation of Liaoning Province, China （Grant No 20032012） and the Scientific Research Foundation of the Higher Education Institute of Liaoning Province, China （Grant No 05L215）.
文摘Some properties related to the NUT-Taub-like spacetime, such as the surface of infinite red-shift, horizon, singularity and the area of the NUT-Taub-like black hole are discussed. Furthermore, the geodesics in the NUT-Taub-like spacetime are obtained in some special cases. Specifically, the circular orbits for a massive particle are derived, which can reduce to the cases of the Schwarzschild spacetime and the NUT-Taub spacetime when m^＊ = 0 and m^＊ 〈〈 M, respectively.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11675198,11875097,11975257,61774072,61574026,and 61971090)the National Key Research and Development Program of China(Grant Nos.2016YFB0400600 and2016YFB0400601)+2 种基金the Fundamental Research Funds for the Central Universities,China(Grant No.DUT19LK45)the China Postdoctoral Science Foundation(Grant No.2016M591434)the Science and Technology Plan of Dalian City,China(Grant No.2018J12GX060).
文摘Nowadays,the superior detection performance of semiconductor neutron detectors is a challenging task.In this paper,we deal with a novel GaN micro-structured neutron detector(GaN-MSND)and compare three different methods such as the method of modulating the trench depth,the method of introducing dielectric layer and p-type inversion region to improve the width of depletion region(W).It is observed that the intensity of electric field can be modulated by scaling the trench depth.On the other hand,the electron blocking region is formed in the detector enveloped with a dielectric layer.Furthermore,the introducing of p-type inversion region produces new p/n junction,which not only promotes the further expansion of the depletion region but also reduces the intensity of electric field produced by main junction.It can be realized that all these methods can considerably enhance the working voltage as well as W.Of them,the improvement on W of GaN-MSND with the p-type inversion region is the most significant and the value of W could reach 12.8μm when the carrier concentration of p-type inversion region is 10^17 cm^-3.Consequently,the value of W is observed to improve 200%for the designed GaN-MSND as compared with that without additional design.This work ensures to the researchers and scientific community the fabrication of GaN-MSND having superior detection limit in the field of intense radiation.
文摘We use a dual Einstein-Kaluza spacetime to calculate the exact energy density of dark energy and dark matter using a novel topological computation method. Starting from the said spacetime and ‘tHooft’s topological renormalon as well as the corresponding symmetry group, we show how the zero set quantum particle and the empty set quantum wave interact with the vacuum and give rise to pure dark energy and pure dark matter all along with ordinary energy density of the cosmos. The consistency of the exact calculation and the accurate observations attests to the reality of ‘tHooft’s renormalon dark matter, pure dark energy and accelerated cosmic expansion.
文摘In this paper,we report the study of the process of fabricating a multi-layermetal micro-structure using UV-LIGA overlay technology,includingmask fabrication,substrate treatment,and UV-LIGA overlay processes.To solve the process problems in the masking procedure,the swelling problemof the first layer of SU-8 thick photoresist was studied experimentally.The 5μmline-width compensation and closed 20μmand 30μmisolation strips were designed and fabricated around the micro-structure pattern.The pore problemin the Ni micro-electroforming layer was analyzed and the electroforming parameters were improved.The pH value of the electroforming solution should be controlled between 3.8 and 4.4 and the current density should be below 3 A/dm^2.To solve the problems of high inner stress and incomplete development of the micro-cylinder hole array with a diameter of 30μm,the lithography process was optimized.The pre-baking temperature was increased via gradient heating and rose every 5℃ from 65℃ to 85℃ and then remained at 85℃ for 50 min–1 h.In addition,the full contact exposure was used.Finally,a multi-layer metal micro-structure with high precision and good quality of microelectroforming layer was fabricated using UV-LIGA overlay technology.
文摘A low-power CO_2 laser is used to deposit Fe powder and mixture of Fe andcarbon powder on substrates respectively, and the macro and micro-structure of the formed samplesare investigated. It is demonstrated that most grains of these samples are equi-axed. This isderived from the high nucleation velocity in the shallow melt pool besides rapid solidification ofthe liquid-state alloy or metal. Bainitic structure, combination of pearlite and ferrite structureand ferrite structure are seen respectively in the samples involving various amounts of carbon owingto no martensitic transformation in these small samples.
文摘Looped light in a recent sophisticated real three-slit experiment is interpreted as a strong justification of the old theoretical Peano-Hilbert spacetime model of Ord and El Naschie. This in turn entails the existence of extra fractal dimensions and consequently of real dark energy density in full agreement with previous analysis as well as accurate measurements and observations of COBE, WMAP, and the type 1a supernova.
文摘Abstract： This paper concerns space-like submanifolds in a pseudo-Riemannianspace-time Sp^m＋p∪→Ep^m＋p＋1 （P ≥ 1）, and proves that connected compact maximalsuace-like submanifolds in a pseudo-Riemannian spacetime Sp^m＋p∪→Ep^m＋p＋1 （P ≥ 1） must be totally umbilical, and also totally geodesic. Particularly, when p = 1, our result is just Montiel＇s in case of H = 0.
基金Supported by the Programme of Introducing Talents of Discipline to Universities (B07018)
文摘To obtain the form error of micro-structured surfaces robustly and accurately, a form er- ror evaluation method was developed based on the real coded genetic algorithm （RCGA）. The meth- od employed the average squared distance as the matching criterion. The point to surface distance was achieved by use of iterative method and the modeling of RCGA for the surface matching was also presented in detail. Parameter selection for RCGA including the crossover rate and population size was discussed. Evaluation results of series simulated surfaces without form error show that this method can achieve the accuracy of root mean square deviation （ Sq ） less than 1 nm and surface pro- file error （ St ） less than 4 nm. Evaluation of the surfaces with different simulated errors illustrates that the proposed method can also robustly obtain the form error with nano-meter precision. The e- valuation of actual measured surfaces further indicates that the proposed method is capable of pre- cisely evaluating micro-structured surfaces.
