Isothermal flashless die forging process of Ti - alloy structural air - frame part with varying thickness rib has been modelled in this paper.The results of present study show that a upside - down trapezoid rib would...Isothermal flashless die forging process of Ti - alloy structural air - frame part with varying thickness rib has been modelled in this paper.The results of present study show that a upside - down trapezoid rib would be formed and buckling would occure as blank is reduced,if the thickness of billet is maller than or equal to the thickness of rib. During modelling process of structural air frame part with E type cross - section rib, the saddle or lap would be formed finally at the middle of transverse rib between ribs with increase in deformation.If metal is allowed to flow out at confluence of longitudinal and transverse rib, the lop defect would be eliminated,, but a pipe cavity is obvious on corresponding loca- tion of blank. of defect formation depends on distance of metal flow ,friction,temperature homoge- neity of the blank and complexity of the part.展开更多
In educational settings,instructors often lead students through hands-on software projects,sometimes engaging two different schools or departments.How can such collaborations be made more efficient,and how can student...In educational settings,instructors often lead students through hands-on software projects,sometimes engaging two different schools or departments.How can such collaborations be made more efficient,and how can students truly experience the importance of teamwork and the impact of organizational structure on project complexity?To answer these questions,we introduce the requirement-driven organization structure(R-DOS)approach,which tightly couples software requirements with the actual development process.By extending problem-frames modeling and focusing on requirements,R-DOS allows educators and students to(1)diagnose structural flaws early,(2)prescribe role-level and communication fixes,and(3)observe-in real time-how poor structure can derail a project while good structure accelerates learning and delivery.展开更多
To resolve the issue regarding inaccurate prediction of the hysteretic behavior by micro-based numerical analysis for partially-restrained（PR）steel frames with solid reinforced concrete（RC）infill walls,an innovati...To resolve the issue regarding inaccurate prediction of the hysteretic behavior by micro-based numerical analysis for partially-restrained（PR）steel frames with solid reinforced concrete（RC）infill walls,an innovative simplified model of composite compression struts is proposed on the basis of experimental observation on the cracking distribution,load transferring mechanism,and failure modes of RC infill walls filled in PR steel frame.The proposed composite compression struts model for the solid RC infill walls is composed ofαinclined struts and main diagonal struts.Theαinclined struts are used to reflect the part of the lateral force resisted by shear connectors along the frame-wall interface,while the main diagonal struts are introduced to take into account the rest of the lateral force transferred along the diagonal direction due to the complicated interaction between the steel frame and RC infill walls.This study derives appropriate formulas for the effective widths of theαinclined strut and main diagonal strut,respectively.An example of PR steel frame with RC infill walls simulating simulated by the composite inclined compression struts model is illustrated.The maximum lateral strength and the hysteresis curve shape obtained from the proposed composite strut model are in good agreement with those from the test results,and the backbone curve of a PR steel frame with RC infill walls can be predicted precisely when the inter-story drift is within 1%.This simplified model can also predict the structural stiffness and the equivalent viscous damping ratio well when the inter-story drift ratio exceeds 0.5%.展开更多
Under the surface peeling of Cu- Fe- P lead frame alloy larger Fe particles were observed by energy dispersive spectroscopy. By using the large strain two-dinension plane strain model and elastic plastic finite elemen...Under the surface peeling of Cu- Fe- P lead frame alloy larger Fe particles were observed by energy dispersive spectroscopy. By using the large strain two-dinension plane strain model and elastic plastic finite element method, the cause for peeling damage of Cu-Fe-P lead frame aUoy was investigated. The results show that when the content of Fe particles is more than 30% at local Fe-rich area the intense stress coacentration in the Fe particle would make the Fe particle broken up. The high equivalent stress mutation and the mismatch of equivalent strain 10% at the two sides of intefrace make it easy to develop the crack and peeling damage on finish rolling. The larger Fe particles in the Cu-Fe-P alloy should be avoided.展开更多
We present a three-party reference frame independent quantum key distribution protocol which can be implemented without any alignment of reference frames between the sender and the receiver.The protocol exploits entan...We present a three-party reference frame independent quantum key distribution protocol which can be implemented without any alignment of reference frames between the sender and the receiver.The protocol exploits entangled states to establish a secret key among three communicating parties.We derive the asymptotic key rate for the proposed protocol against collective attacks and perform a finite-size key security analysis against general attacks in the presence of statistical fluctuations.We investigate the impact of reference frame misalignment on the stability of our protocol,and we obtain a transmission distance of 180 km,200 km,and 230 km for rotation of reference framesβ=π/6,β=π/8 andβ=0,respectively.Remarkably,our results demonstrate that our proposed protocol is not heavily affected by an increase in misalignment of reference frames as the achievable transmission distances are still comparable to the case where there is no misalignment in reference frames(whenβ=0).We also simulate the performance of our protocol for a fixed number of signals.Our results demonstrate that the protocol can achieve an effective key generation rate over a transmission distance of about 120 km with realistic 107 finite data signals and approximately achieve 195 km with 109 signals.Moreover,our proposed protocol is robust against noise in the quantum channel and achieves a threshold error rate of 22.7%.展开更多
The π-tangle is used to study the behavior of entanglement of a nonmaximal tripartite state of both Dirac and scMar fields in accelerated frame. For Dirac fields, the degree of degradation with acceleration of both o...The π-tangle is used to study the behavior of entanglement of a nonmaximal tripartite state of both Dirac and scMar fields in accelerated frame. For Dirac fields, the degree of degradation with acceleration of both one-tangle of accelerated observer and π-tangle, for the same initial entanglement, is different by just interchanging the values of probability amplitudes. A fraction of both one-tangles and the π-tangle always survives for any choice of acceleration and the degree of initial entanglement. For scalar field, the one-tangle of accelerated observer depends on the choice of values of probability amplitudes and it vanishes in the range of infinite acceleration, whereas for 1r-tangle this is not always true. The dependence of π-tangle on probability amplitudes varies with acceleration. In the lower range of acceleration, its behavior changes by switching between the values of probability amplitudes and for larger values of acceleration this dependence on probability amplitudes vanishes. Interestingly, unlike bipartite entanglement, the degradation of π-tangle against acceleration in the case of sca/ar fields is slower than for Dirac fields.展开更多
We present the entanglement measures of a tetrapartite W-class entangled system in a noninertial frame, where the transformation between Minkowski and Rindler coordinates is applied.Two cases are considered.First, whe...We present the entanglement measures of a tetrapartite W-class entangled system in a noninertial frame, where the transformation between Minkowski and Rindler coordinates is applied.Two cases are considered.First, when one qubit has uniform acceleration whilst the other three remain stationary.Second, when two qubits have nonuniform accelerations and the others stay inertial.The 1–1 tangle, 1–3 tangle, and whole entanglement measurements π4 and Π4, are studied and illustrated with graphics through their dependence on the acceleration parameter rd for the first case and rc and rd for the second case.It is found that the negativities(1–1 tangle and 1–3 tangle) and π-tangle decrease when the acceleration parameter rd or in the second case rc and rd increase, remaining a nonzero entanglement in the majority of the results.This means that the system will be always entangled except for special cases.It is shown that only the 1–1 tangle for the first case vanishes at infinite accelerations, but for the second case the 1–1 tangle disappears completely when r > 0.472473.An analytical expression for the von Neumann information entropy of the system is found and we note that it increases with the acceleration parameter.展开更多
Using a single-mode approximation, we carry out the entanglement measures, e.g., the negativity and von Neumann entropy when a tetrapartite generalized GHZ state is treated in a noninertial frame, but only uniform acc...Using a single-mode approximation, we carry out the entanglement measures, e.g., the negativity and von Neumann entropy when a tetrapartite generalized GHZ state is treated in a noninertial frame, but only uniform acceleration is considered for simplicity. In terms of explicit negativity calculated, we notice that the difference between the algebraic average π_(4) and geometric average Π_(4) is very small with the increasing accelerated observers and they are totally equal when all four qubits are accelerated simultaneously. The entanglement properties are discussed from one accelerated observer to all four accelerated observers. It is shown that the entanglement still exists even if the acceleration parameter r goes to infinity. It is interesting to discover that all 1-1 tangles are equal to zero, but 1-3 and 2-2 tangles always decrease when the acceleration parameter γ increases. We also study the von Neumann entropy and find that it increases with the number of the accelerated observers. In addition, we find that the von Neumann entropy S_(ABCDI), S_(ABCIDI), S_(ABICIDI) and S_(AIBICIDI) always decrease with the controllable angle θ, while the entropies S_(3-3 non), S_(3-2 non), S_(3-1 non) and S_(3-0 non) first increase with the angle θ and then decrease with it.展开更多
Considering the spin degree of freedom of the Dirac field, we study the entanglement behavior of a different class of communication channel and teleportation of three-dimensional single particle state in noninertial f...Considering the spin degree of freedom of the Dirac field, we study the entanglement behavior of a different class of communication channel and teleportation of three-dimensional single particle state in noninertial frames. Numerical analysis shows that the communication channel in our scheme can offer enough distillable entanglement for the teleportation protocol. Moreover, the teleportation protocol could work well if Rob＇s acceleration is not very big, but the fidelity of the teleportation is still reduced due to the Unruh effect.展开更多
The paper examines the change of the relativistic kinetic energy of a free particle due to the velocity change of the motion frame in a special case when this reduction leads to the kinetic energy equal to zero. The d...The paper examines the change of the relativistic kinetic energy of a free particle due to the velocity change of the motion frame in a special case when this reduction leads to the kinetic energy equal to zero. The difference of velocities gives a functional dependent solely on the velocity frame and original velocity of the particle. An analysis applied to the functional gives simple formulae for the extremal values of the mentioned velocity parameters. In the next step, solutions of the equation presented with the functional provide us with the velocities necessary for the vanishing property of the kinetic energy. A characteristic point is that a condition of the velocity of the motion frame smaller than the velocity of light is obtained directly in the applied formalism. This property holds with no reference done to the well-known postulate of the dominant value of the light velocity entering the relativity theory.展开更多
The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave...The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave infrared wavelengths as beacon light can reduce atmospheric absorption and signal attenuation.However,there are strong non-uniformity and blind pixels in the short-wave infrared image,which makes the image distorted and leads to the decrease of spot centroid positioning accuracy.Therefore,the high-precision localization of the spot centroid of the short-wave infrared images is of great research significance.A high-precision spot centroid positioning model for short-wave infrared is proposed to correct for non-uniformity and blind pixels in short-wave infrared images and quantify the localization errors caused by the two,further model-based localization error simulations are performed,and a novel spot centroid positioning payload for satellite laser communications has been designed using the latest 640×512 planar array InGaAs shortwave infrared detector.The experimental results show that the non-uniformity of the corrected image is reduced from 7%to 0.6%,the blind pixels rejection rate reaches 100%,the frame rate can be up to 2000 Hz,and the spot centroid localization accuracy is as high as 0.1 pixel point,which realizes high-precision spot centroid localization of high-frame-frequency short-wave infrared images.展开更多
Stepping out of Danyang Railway Station,the large sign reading“China Danyang Optical City”immediately comes into view across the road.Inside the bustling marketplace,a dazzling array of eyeglass frames and lenses is...Stepping out of Danyang Railway Station,the large sign reading“China Danyang Optical City”immediately comes into view across the road.Inside the bustling marketplace,a dazzling array of eyeglass frames and lenses is neatly displayed in rows of shops,attracting consumers from across the country.展开更多
Ensuring the secure transmission of secret messages,particularly through video—one of the most widely used media formats—is a critical challenge in the field of information security.Relying on a single-layered secur...Ensuring the secure transmission of secret messages,particularly through video—one of the most widely used media formats—is a critical challenge in the field of information security.Relying on a single-layered security approach is often insufficient for safeguarding sensitive data.This study proposes a triple-lightweight cryptographic and steganographic model that integrates the Hill Cipher Technique(HCT),Rotation Left Digits(RLD),and Discrete Wavelet Transform(DWT)to embed secret messages within video frames securely.The approach begins with encrypting the secret text using a private key matrix(PK^(1))of size 2×2 up to 6×6 via HCT.A second encryption layer is applied using a dynamic private key(PK2)derived from the RGB pixel values of the video frame,resulting in a rotated cipher.The doubly encrypted message is then embedded into the video frames using the DWT method.Upon transmission,the concealed message is extracted using inverse DWT and decrypted in two steps—first with PK2 and then with the inverse of PK^(1).Experiments conducted using MPEG video sequences and message lengths ranging from 10 to 300 bytes demonstrate strong performance in terms of Mean Square Error(MSE),Peak Signal-to-Noise Ratio(PSNR),and Correlation Coefficient(CC)between original and encrypted messages.The similarity between original and stego frames is further validated using Structural Similarity Index(SSIM),Mean Absolute Error(MAE),Number of Pixel Change Rate(NPCR),and Unified Average Changing Intensity(UACI).Results confirm that utilizing video frames to generate PK2 offers superior security compared to static key images.Moreover,the indistinguishability between original and stego frames highlights the method’s robustness against visual and statistical attacks.展开更多
We connect magic(non-stabilizer)states,symmetric informationally complete positive operator valued measures(SIC-POVMs),and mutually unbiased bases(MUBs)in the context of group frames,and study their interplay.Magic st...We connect magic(non-stabilizer)states,symmetric informationally complete positive operator valued measures(SIC-POVMs),and mutually unbiased bases(MUBs)in the context of group frames,and study their interplay.Magic states are quantum resources in the stabilizer formalism of quantum computation.SIC-POVMs and MUBs are fundamental structures in quantum information theory with many applications in quantum foundations,quantum state tomography,and quantum cryptography,etc.In this work,we study group frames constructed from some prominent magic states,and further investigate their applications.Our method exploits the orbit of discrete Heisenberg-Weyl group acting on an initial fiducial state.We quantify the distance of the group frames from SIC-POVMs and MUBs,respectively.As a simple corollary,we reproduce a complete family of MUBs of any prime dimensional system by introducing the concept of MUB fiducial states,analogous to the well-known SIC-POVM fiducial states.We present an intuitive and direct construction of MUB fiducial states via quantum T-gates,and demonstrate that for the qubit system,there are twelve MUB fiducial states,which coincide with the H-type magic states.We compare MUB fiducial states and SIC-POVM fiducial states from the perspective of magic resource for stabilizer quantum computation.We further pose the challenging issue of identifying all MUB fiducial states in general dimensions.展开更多
This study presents the development of a Magnesium Alloy Seat Frame(MASF),supported by case studies from automotive original equipment manufacturers.The process covers integrated design,simulation,manufacturing,and te...This study presents the development of a Magnesium Alloy Seat Frame(MASF),supported by case studies from automotive original equipment manufacturers.The process covers integrated design,simulation,manufacturing,and testing,aiming to boost industry confidence in Mg alloy applications.A novel structural design is developed that integrates the headrest with the backrest,achieving a balance between lightweight performance and safety.Structural optimization is guided by stress–strain simulations under diverse conditions within a complete forward development process.Casting simulations are conducted to analyze process characteristics,resulting in a verified MASF yield rate exceeding 90%.The final 9.88 kg MASF represents a 24.6%(3.23 kg)weight reduction versus a steel seat.This research contributes to advancements in defect control technology for large die casting magnesium alloy parts and has broad implications for their application in automotive manufacturing.展开更多
Jiangsu Niupai Machinery&Elecronics Co,ltd.is National Specialized and New"Little Giant"Enterprise,National High&New Technological Enterprise,Jiangsu Provincial Research Center of Loom Shedding Engin...Jiangsu Niupai Machinery&Elecronics Co,ltd.is National Specialized and New"Little Giant"Enterprise,National High&New Technological Enterprise,Jiangsu Provincial Research Center of Loom Shedding Engineering Technology and Jiangsu Provincial Enterprise Technology Center.The company has obtained SGS-certified ISO9001 quality management system,a globally recognized standard.Niupai specializes in the R&D and manufacturing of cam shedding device,dobby shedding device,jacquard shedding device and heald frames for water-jet looms,air-jet looms as well as rapier looms.展开更多
Based on the Etihad Railway Station Project,this study selects a single-span frame bridge with a clear span of 7.3 meters as the research object.A comprehensive structural design process was conducted following the AR...Based on the Etihad Railway Station Project,this study selects a single-span frame bridge with a clear span of 7.3 meters as the research object.A comprehensive structural design process was conducted following the AREMA(2023),Manual for Railway Engineering-Volume 2-Structures,with systematic comparisons of techno-economic differences between the Chinese and American codes through recalculation verification and equivalent-precision design methods.The findings reveal:Recalculation using the Chinese code for identical structural dimensions and reinforcement layouts demonstrates that AREMA code exhibits greater conservatism in both strength requirements and crack control;Under equivalent precision design principles,the Chinese code solution reduces reinforcement by 4.128 t tons and a 19.5%reduction in reinforcement at critical sections compared to the AREMA code,indicating slightly reduced economic efficiency of the AREMA code.This research provides quantitative references for standardized design and specification integration in cross-border railway engineering projects.展开更多
Frame blades were used to replace traditional propeller blades to enhance the leaching step efficiency of Becher process.A combined approach of leaching,electrochemical experiments,and numerical simulations was employ...Frame blades were used to replace traditional propeller blades to enhance the leaching step efficiency of Becher process.A combined approach of leaching,electrochemical experiments,and numerical simulations was employed.Results demonstrate a significant improvement in leaching efficiency using frame blades compared to propellers,reducing reaction time from 15 to 10 h.Even at a stirring speed of 300 r/min,frame blades perform better than propellers at 500 r/min.Kinetics analysis indicates that the leaching process is controlled by surface chemical reactions.CFD-PBM simulations reveal that frame blades at 300 r/min generate larger bubbles and higher turbulent kinetic energy than propeller blades at 500 r/min.Frame blades enhance leaching efficiency by refining bubble size to improve oxygen mass transfer and by increasing turbulent kinetic energy for better mixing.展开更多
To evaluate the dynamic interactions between debris flows,entrained material sources,and infrastructure in the Naojiao Gully watershed of Beijing,and to develop a predictive framework for mitigating geohazard risks th...To evaluate the dynamic interactions between debris flows,entrained material sources,and infrastructure in the Naojiao Gully watershed of Beijing,and to develop a predictive framework for mitigating geohazard risks through energy-based strategies,debris flow dynamics are investigated,a coupled SPH-DEM-FEM multiscale model integrating fluid dynamics(SPH),granular mechanics(DEM),and structural mechanics(FEM)is developed to simulate debris flow propagation,material source behavior,and frame structure responses,and to capture cross-scale failure mechanisms.Key findings include the identification of a critical flow velocity threshold of 12 m/s,beyond which solid-phase kinetic energy dominates,inducing 60%-75%capacity loss in central columns via through-cracking.Furthermore,a novel compound failure criterion is proposed based on the solid-liquid energy proportion.The model achieves a boulder impact force prediction error of only 5.47%,significantly outperforming empirical methods in cross-scale accuracy.An optimized 0.3 m layered configuration experimentally reduces impact pulse peaks by 57%through directed energy redistribution,thereby shifting mitigation strategies from structural reinforcement to media modulation.These results establish a robust framework for quantifying failure thresholds,enhancing predictive precision,and innovating energy-based mitigation.By bridging multiscale modeling gaps in geohazard analysis,this study provides actionable insights for infrastructure resilience in debris flow-prone regions through energycentric design principles.展开更多
文摘Isothermal flashless die forging process of Ti - alloy structural air - frame part with varying thickness rib has been modelled in this paper.The results of present study show that a upside - down trapezoid rib would be formed and buckling would occure as blank is reduced,if the thickness of billet is maller than or equal to the thickness of rib. During modelling process of structural air frame part with E type cross - section rib, the saddle or lap would be formed finally at the middle of transverse rib between ribs with increase in deformation.If metal is allowed to flow out at confluence of longitudinal and transverse rib, the lop defect would be eliminated,, but a pipe cavity is obvious on corresponding loca- tion of blank. of defect formation depends on distance of metal flow ,friction,temperature homoge- neity of the blank and complexity of the part.
基金supported by the National Natural Science Foundation of China(No.62362006)Guangxi Science and Technology Project(Key Research&Development)(No.GuiKeAB24010343)+1 种基金Guangxi“Bagui Scholar”Teams for Innovation and Research,Innovation Project of Guangxi Graduate Education(No.YCSW2025193)Guangxi Collaborative Innovation Center of Multi-source Information Integration and Intelligent Processing.
文摘In educational settings,instructors often lead students through hands-on software projects,sometimes engaging two different schools or departments.How can such collaborations be made more efficient,and how can students truly experience the importance of teamwork and the impact of organizational structure on project complexity?To answer these questions,we introduce the requirement-driven organization structure(R-DOS)approach,which tightly couples software requirements with the actual development process.By extending problem-frames modeling and focusing on requirements,R-DOS allows educators and students to(1)diagnose structural flaws early,(2)prescribe role-level and communication fixes,and(3)observe-in real time-how poor structure can derail a project while good structure accelerates learning and delivery.
基金National Science Foundation of China under Grant No.51108292,and Qing Lan Project of Jiangsu Province
文摘To resolve the issue regarding inaccurate prediction of the hysteretic behavior by micro-based numerical analysis for partially-restrained（PR）steel frames with solid reinforced concrete（RC）infill walls,an innovative simplified model of composite compression struts is proposed on the basis of experimental observation on the cracking distribution,load transferring mechanism,and failure modes of RC infill walls filled in PR steel frame.The proposed composite compression struts model for the solid RC infill walls is composed ofαinclined struts and main diagonal struts.Theαinclined struts are used to reflect the part of the lateral force resisted by shear connectors along the frame-wall interface,while the main diagonal struts are introduced to take into account the rest of the lateral force transferred along the diagonal direction due to the complicated interaction between the steel frame and RC infill walls.This study derives appropriate formulas for the effective widths of theαinclined strut and main diagonal strut,respectively.An example of PR steel frame with RC infill walls simulating simulated by the composite inclined compression struts model is illustrated.The maximum lateral strength and the hysteresis curve shape obtained from the proposed composite strut model are in good agreement with those from the test results,and the backbone curve of a PR steel frame with RC infill walls can be predicted precisely when the inter-story drift is within 1%.This simplified model can also predict the structural stiffness and the equivalent viscous damping ratio well when the inter-story drift ratio exceeds 0.5%.
基金Funded by the National "863" Plan of China ( No.2002AA331112) ,the Doctorate Foundation of Northwestern Poly-technical University,andthe Science Research Foundation of HenanUniversity of Science and Technology(No.2006ZY041)
文摘Under the surface peeling of Cu- Fe- P lead frame alloy larger Fe particles were observed by energy dispersive spectroscopy. By using the large strain two-dinension plane strain model and elastic plastic finite element method, the cause for peeling damage of Cu-Fe-P lead frame aUoy was investigated. The results show that when the content of Fe particles is more than 30% at local Fe-rich area the intense stress coacentration in the Fe particle would make the Fe particle broken up. The high equivalent stress mutation and the mismatch of equivalent strain 10% at the two sides of intefrace make it easy to develop the crack and peeling damage on finish rolling. The larger Fe particles in the Cu-Fe-P alloy should be avoided.
基金Project supported by the Botswana International University of Science and Technology Research Initiation(Grant Nos.R00015 and S00100)。
文摘We present a three-party reference frame independent quantum key distribution protocol which can be implemented without any alignment of reference frames between the sender and the receiver.The protocol exploits entangled states to establish a secret key among three communicating parties.We derive the asymptotic key rate for the proposed protocol against collective attacks and perform a finite-size key security analysis against general attacks in the presence of statistical fluctuations.We investigate the impact of reference frame misalignment on the stability of our protocol,and we obtain a transmission distance of 180 km,200 km,and 230 km for rotation of reference framesβ=π/6,β=π/8 andβ=0,respectively.Remarkably,our results demonstrate that our proposed protocol is not heavily affected by an increase in misalignment of reference frames as the achievable transmission distances are still comparable to the case where there is no misalignment in reference frames(whenβ=0).We also simulate the performance of our protocol for a fixed number of signals.Our results demonstrate that the protocol can achieve an effective key generation rate over a transmission distance of about 120 km with realistic 107 finite data signals and approximately achieve 195 km with 109 signals.Moreover,our proposed protocol is robust against noise in the quantum channel and achieves a threshold error rate of 22.7%.
文摘The π-tangle is used to study the behavior of entanglement of a nonmaximal tripartite state of both Dirac and scMar fields in accelerated frame. For Dirac fields, the degree of degradation with acceleration of both one-tangle of accelerated observer and π-tangle, for the same initial entanglement, is different by just interchanging the values of probability amplitudes. A fraction of both one-tangles and the π-tangle always survives for any choice of acceleration and the degree of initial entanglement. For scalar field, the one-tangle of accelerated observer depends on the choice of values of probability amplitudes and it vanishes in the range of infinite acceleration, whereas for 1r-tangle this is not always true. The dependence of π-tangle on probability amplitudes varies with acceleration. In the lower range of acceleration, its behavior changes by switching between the values of probability amplitudes and for larger values of acceleration this dependence on probability amplitudes vanishes. Interestingly, unlike bipartite entanglement, the degradation of π-tangle against acceleration in the case of sca/ar fields is slower than for Dirac fields.
基金Project partially supported by the CONACYT,Mexico under the Grant No.288856-CB-2016partially by 20190234-SIP-IPN,Mexicopartially by the program XXVIII Verano de la Investigación Científica 2018 supported by the Academia Mexicana de Ciencias
文摘We present the entanglement measures of a tetrapartite W-class entangled system in a noninertial frame, where the transformation between Minkowski and Rindler coordinates is applied.Two cases are considered.First, when one qubit has uniform acceleration whilst the other three remain stationary.Second, when two qubits have nonuniform accelerations and the others stay inertial.The 1–1 tangle, 1–3 tangle, and whole entanglement measurements π4 and Π4, are studied and illustrated with graphics through their dependence on the acceleration parameter rd for the first case and rc and rd for the second case.It is found that the negativities(1–1 tangle and 1–3 tangle) and π-tangle decrease when the acceleration parameter rd or in the second case rc and rd increase, remaining a nonzero entanglement in the majority of the results.This means that the system will be always entangled except for special cases.It is shown that only the 1–1 tangle for the first case vanishes at infinite accelerations, but for the second case the 1–1 tangle disappears completely when r > 0.472473.An analytical expression for the von Neumann information entropy of the system is found and we note that it increases with the acceleration parameter.
基金partially supported by the 20210414-SIPIPN, Mexico。
文摘Using a single-mode approximation, we carry out the entanglement measures, e.g., the negativity and von Neumann entropy when a tetrapartite generalized GHZ state is treated in a noninertial frame, but only uniform acceleration is considered for simplicity. In terms of explicit negativity calculated, we notice that the difference between the algebraic average π_(4) and geometric average Π_(4) is very small with the increasing accelerated observers and they are totally equal when all four qubits are accelerated simultaneously. The entanglement properties are discussed from one accelerated observer to all four accelerated observers. It is shown that the entanglement still exists even if the acceleration parameter r goes to infinity. It is interesting to discover that all 1-1 tangles are equal to zero, but 1-3 and 2-2 tangles always decrease when the acceleration parameter γ increases. We also study the von Neumann entropy and find that it increases with the number of the accelerated observers. In addition, we find that the von Neumann entropy S_(ABCDI), S_(ABCIDI), S_(ABICIDI) and S_(AIBICIDI) always decrease with the controllable angle θ, while the entropies S_(3-3 non), S_(3-2 non), S_(3-1 non) and S_(3-0 non) first increase with the angle θ and then decrease with it.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11064016 and 61068001)
文摘Considering the spin degree of freedom of the Dirac field, we study the entanglement behavior of a different class of communication channel and teleportation of three-dimensional single particle state in noninertial frames. Numerical analysis shows that the communication channel in our scheme can offer enough distillable entanglement for the teleportation protocol. Moreover, the teleportation protocol could work well if Rob＇s acceleration is not very big, but the fidelity of the teleportation is still reduced due to the Unruh effect.
文摘The paper examines the change of the relativistic kinetic energy of a free particle due to the velocity change of the motion frame in a special case when this reduction leads to the kinetic energy equal to zero. The difference of velocities gives a functional dependent solely on the velocity frame and original velocity of the particle. An analysis applied to the functional gives simple formulae for the extremal values of the mentioned velocity parameters. In the next step, solutions of the equation presented with the functional provide us with the velocities necessary for the vanishing property of the kinetic energy. A characteristic point is that a condition of the velocity of the motion frame smaller than the velocity of light is obtained directly in the applied formalism. This property holds with no reference done to the well-known postulate of the dominant value of the light velocity entering the relativity theory.
基金Supported by the Short-wave Infrared Camera Systems(B025F40622024)。
文摘The accuracy of spot centroid positioning has a significant impact on the tracking accuracy of the system and the stability of the laser link construction.In satellite laser communication systems,the use of short-wave infrared wavelengths as beacon light can reduce atmospheric absorption and signal attenuation.However,there are strong non-uniformity and blind pixels in the short-wave infrared image,which makes the image distorted and leads to the decrease of spot centroid positioning accuracy.Therefore,the high-precision localization of the spot centroid of the short-wave infrared images is of great research significance.A high-precision spot centroid positioning model for short-wave infrared is proposed to correct for non-uniformity and blind pixels in short-wave infrared images and quantify the localization errors caused by the two,further model-based localization error simulations are performed,and a novel spot centroid positioning payload for satellite laser communications has been designed using the latest 640×512 planar array InGaAs shortwave infrared detector.The experimental results show that the non-uniformity of the corrected image is reduced from 7%to 0.6%,the blind pixels rejection rate reaches 100%,the frame rate can be up to 2000 Hz,and the spot centroid localization accuracy is as high as 0.1 pixel point,which realizes high-precision spot centroid localization of high-frame-frequency short-wave infrared images.
文摘Stepping out of Danyang Railway Station,the large sign reading“China Danyang Optical City”immediately comes into view across the road.Inside the bustling marketplace,a dazzling array of eyeglass frames and lenses is neatly displayed in rows of shops,attracting consumers from across the country.
文摘Ensuring the secure transmission of secret messages,particularly through video—one of the most widely used media formats—is a critical challenge in the field of information security.Relying on a single-layered security approach is often insufficient for safeguarding sensitive data.This study proposes a triple-lightweight cryptographic and steganographic model that integrates the Hill Cipher Technique(HCT),Rotation Left Digits(RLD),and Discrete Wavelet Transform(DWT)to embed secret messages within video frames securely.The approach begins with encrypting the secret text using a private key matrix(PK^(1))of size 2×2 up to 6×6 via HCT.A second encryption layer is applied using a dynamic private key(PK2)derived from the RGB pixel values of the video frame,resulting in a rotated cipher.The doubly encrypted message is then embedded into the video frames using the DWT method.Upon transmission,the concealed message is extracted using inverse DWT and decrypted in two steps—first with PK2 and then with the inverse of PK^(1).Experiments conducted using MPEG video sequences and message lengths ranging from 10 to 300 bytes demonstrate strong performance in terms of Mean Square Error(MSE),Peak Signal-to-Noise Ratio(PSNR),and Correlation Coefficient(CC)between original and encrypted messages.The similarity between original and stego frames is further validated using Structural Similarity Index(SSIM),Mean Absolute Error(MAE),Number of Pixel Change Rate(NPCR),and Unified Average Changing Intensity(UACI).Results confirm that utilizing video frames to generate PK2 offers superior security compared to static key images.Moreover,the indistinguishability between original and stego frames highlights the method’s robustness against visual and statistical attacks.
基金supported by the National Key R&D Program of China,Grant No.2020YFA0712700the National Natural Science Foundation of China‘Mathematical Basic Theory of Quantum Computing’special project,Grant No.12341103。
文摘We connect magic(non-stabilizer)states,symmetric informationally complete positive operator valued measures(SIC-POVMs),and mutually unbiased bases(MUBs)in the context of group frames,and study their interplay.Magic states are quantum resources in the stabilizer formalism of quantum computation.SIC-POVMs and MUBs are fundamental structures in quantum information theory with many applications in quantum foundations,quantum state tomography,and quantum cryptography,etc.In this work,we study group frames constructed from some prominent magic states,and further investigate their applications.Our method exploits the orbit of discrete Heisenberg-Weyl group acting on an initial fiducial state.We quantify the distance of the group frames from SIC-POVMs and MUBs,respectively.As a simple corollary,we reproduce a complete family of MUBs of any prime dimensional system by introducing the concept of MUB fiducial states,analogous to the well-known SIC-POVM fiducial states.We present an intuitive and direct construction of MUB fiducial states via quantum T-gates,and demonstrate that for the qubit system,there are twelve MUB fiducial states,which coincide with the H-type magic states.We compare MUB fiducial states and SIC-POVM fiducial states from the perspective of magic resource for stabilizer quantum computation.We further pose the challenging issue of identifying all MUB fiducial states in general dimensions.
基金supported in part by the project is supported partly by National Key Research and Development Program of China(no.2022YFB2503504)Chongqing Technology Innovation and Application Development Project(no.CSTB2022TIAD-DEX0011)China Scholarship Council.
文摘This study presents the development of a Magnesium Alloy Seat Frame(MASF),supported by case studies from automotive original equipment manufacturers.The process covers integrated design,simulation,manufacturing,and testing,aiming to boost industry confidence in Mg alloy applications.A novel structural design is developed that integrates the headrest with the backrest,achieving a balance between lightweight performance and safety.Structural optimization is guided by stress–strain simulations under diverse conditions within a complete forward development process.Casting simulations are conducted to analyze process characteristics,resulting in a verified MASF yield rate exceeding 90%.The final 9.88 kg MASF represents a 24.6%(3.23 kg)weight reduction versus a steel seat.This research contributes to advancements in defect control technology for large die casting magnesium alloy parts and has broad implications for their application in automotive manufacturing.
文摘Jiangsu Niupai Machinery&Elecronics Co,ltd.is National Specialized and New"Little Giant"Enterprise,National High&New Technological Enterprise,Jiangsu Provincial Research Center of Loom Shedding Engineering Technology and Jiangsu Provincial Enterprise Technology Center.The company has obtained SGS-certified ISO9001 quality management system,a globally recognized standard.Niupai specializes in the R&D and manufacturing of cam shedding device,dobby shedding device,jacquard shedding device and heald frames for water-jet looms,air-jet looms as well as rapier looms.
文摘Based on the Etihad Railway Station Project,this study selects a single-span frame bridge with a clear span of 7.3 meters as the research object.A comprehensive structural design process was conducted following the AREMA(2023),Manual for Railway Engineering-Volume 2-Structures,with systematic comparisons of techno-economic differences between the Chinese and American codes through recalculation verification and equivalent-precision design methods.The findings reveal:Recalculation using the Chinese code for identical structural dimensions and reinforcement layouts demonstrates that AREMA code exhibits greater conservatism in both strength requirements and crack control;Under equivalent precision design principles,the Chinese code solution reduces reinforcement by 4.128 t tons and a 19.5%reduction in reinforcement at critical sections compared to the AREMA code,indicating slightly reduced economic efficiency of the AREMA code.This research provides quantitative references for standardized design and specification integration in cross-border railway engineering projects.
基金supported by the National Natural Science Foundation of China(No.U1908225)the Cross-Integration and Collaborative Development Project of Northeastern University,China(No.N2225013).
文摘Frame blades were used to replace traditional propeller blades to enhance the leaching step efficiency of Becher process.A combined approach of leaching,electrochemical experiments,and numerical simulations was employed.Results demonstrate a significant improvement in leaching efficiency using frame blades compared to propellers,reducing reaction time from 15 to 10 h.Even at a stirring speed of 300 r/min,frame blades perform better than propellers at 500 r/min.Kinetics analysis indicates that the leaching process is controlled by surface chemical reactions.CFD-PBM simulations reveal that frame blades at 300 r/min generate larger bubbles and higher turbulent kinetic energy than propeller blades at 500 r/min.Frame blades enhance leaching efficiency by refining bubble size to improve oxygen mass transfer and by increasing turbulent kinetic energy for better mixing.
基金funded by the Natural Science Foundation of Hebei Province(D2025201012)Highlevel Innovative Talents Program of Hebei University(Grant No.521100222055)President's Fund of Hebei University(Grant No.XZJJ202205)。
文摘To evaluate the dynamic interactions between debris flows,entrained material sources,and infrastructure in the Naojiao Gully watershed of Beijing,and to develop a predictive framework for mitigating geohazard risks through energy-based strategies,debris flow dynamics are investigated,a coupled SPH-DEM-FEM multiscale model integrating fluid dynamics(SPH),granular mechanics(DEM),and structural mechanics(FEM)is developed to simulate debris flow propagation,material source behavior,and frame structure responses,and to capture cross-scale failure mechanisms.Key findings include the identification of a critical flow velocity threshold of 12 m/s,beyond which solid-phase kinetic energy dominates,inducing 60%-75%capacity loss in central columns via through-cracking.Furthermore,a novel compound failure criterion is proposed based on the solid-liquid energy proportion.The model achieves a boulder impact force prediction error of only 5.47%,significantly outperforming empirical methods in cross-scale accuracy.An optimized 0.3 m layered configuration experimentally reduces impact pulse peaks by 57%through directed energy redistribution,thereby shifting mitigation strategies from structural reinforcement to media modulation.These results establish a robust framework for quantifying failure thresholds,enhancing predictive precision,and innovating energy-based mitigation.By bridging multiscale modeling gaps in geohazard analysis,this study provides actionable insights for infrastructure resilience in debris flow-prone regions through energycentric design principles.
