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The Lightweight Edge-Side Fault Diagnosis Approach Based on Spiking Neural Network
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作者 Jingting Mei Yang Yang +2 位作者 Zhipeng Gao Lanlan Rui Yijing Lin 《Computers, Materials & Continua》 SCIE EI 2024年第6期4883-4904,共22页
Network fault diagnosis methods play a vital role in maintaining network service quality and enhancing user experience as an integral component of intelligent network management.Considering the unique characteristics ... Network fault diagnosis methods play a vital role in maintaining network service quality and enhancing user experience as an integral component of intelligent network management.Considering the unique characteristics of edge networks,such as limited resources,complex network faults,and the need for high real-time performance,enhancing and optimizing existing network fault diagnosis methods is necessary.Therefore,this paper proposes the lightweight edge-side fault diagnosis approach based on a spiking neural network(LSNN).Firstly,we use the Izhikevich neurons model to replace the Leaky Integrate and Fire(LIF)neurons model in the LSNN model.Izhikevich neurons inherit the simplicity of LIF neurons but also possess richer behavioral characteristics and flexibility to handle diverse data inputs.Inspired by Fast Spiking Interneurons(FSIs)with a high-frequency firing pattern,we use the parameters of FSIs.Secondly,inspired by the connection mode based on spiking dynamics in the basal ganglia(BG)area of the brain,we propose the pruning approach based on the FSIs of the BG in LSNN to improve computational efficiency and reduce the demand for computing resources and energy consumption.Furthermore,we propose a multiple iterative Dynamic Spike Timing Dependent Plasticity(DSTDP)algorithm to enhance the accuracy of the LSNN model.Experiments on two server fault datasets demonstrate significant precision,recall,and F1 improvements across three diagnosis dimensions.Simultaneously,lightweight indicators such as Params and FLOPs significantly reduced,showcasing the LSNN’s advanced performance and model efficiency.To conclude,experiment results on a pair of datasets indicate that the LSNN model surpasses traditional models and achieves cutting-edge outcomes in network fault diagnosis tasks. 展开更多
关键词 Network fault diagnosis edge networks Izhikevich neurons PRUNING dynamic spike timing dependent plasticity learning
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Zeno and the Wrong Understanding of Motion—A Philosophical-Mathematical Inquiry into the Concept of Finitude as a Peculiarity of Infinity
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作者 Andreas Herberg-Rothe 《Journal of Applied Mathematics and Physics》 2024年第3期912-929,共18页
In contrast to the solutions of applied mathematics to Zeno’s paradoxes, I focus on the concept of motion and show that, by distinguishing two different forms of motion, Zeno’s apparent paradoxes are not paradoxical... In contrast to the solutions of applied mathematics to Zeno’s paradoxes, I focus on the concept of motion and show that, by distinguishing two different forms of motion, Zeno’s apparent paradoxes are not paradoxical at all. Zeno’s paradoxes indirectly prove that distances are not composed of extensionless points and, in general, that a higher dimension cannot be completely composed of lower ones. Conversely, lower dimensions can be understood as special cases of higher dimensions. To illustrate this approach, I consider Cantor’s only apparent proof that the real numbers are uncountable. However, his widely accepted indirect proof has the disadvantage that it depends on whether there is another way to make the real numbers countable. Cantor rightly assumes that there can be no smallest number between 0 and 1, and therefore no beginning of counting. For this reason he arbitrarily lists the real numbers in order to show with his diagonal method that this list can never be complete. The situation is different if we start with the largest number between 0 and 1 (0.999…) and use the method of an inverted triangle, which can be understood as a special fractal form. Here we can construct a vertical and a horizontal stratification with which it is actually possible to construct all real numbers between 0 and 1 without exception. Each column is infinite, and each number in that column is the starting point of a new triangle, while each row is finite. Even in a simple sine curve, we experience finiteness with respect to the y-axis and infinity with respect to the x-axis. The first parts of this article show that Zeno’s assumptions contradict the concept of motion as such, so it is not surprising that this misconstruction leads to contradictions. In the last part, I discuss Cantor’s diagonal method and explain the method of an inverted triangle that is internally structured like a fractal by repeating this inverted triangle at each column. The consequence is that we encounter two very different methods of counting. Vertically it is continuous, horizontally it is discrete. While Frege, Tarski, Cantor, Gödel and the Vienna Circle tried to derive the higher dimension from the lower, a procedure that always leads to new contradictions and antinomies (Tarski, Russell), I take the opposite approach here, in which I derive the lower dimension from the higher. This perspective seems to fail because Tarski, Russell, Wittgenstein, and especially the Vienna Circle have shown that the completeness of the absolute itself is logically contradictory. For this reason, we agree with Hegel in assuming that we can never fully comprehend the Absolute, but only its particular manifestations—otherwise we would be putting ourselves in the place of the Absolute, or even God. Nevertheless, we can understand the Absolute in its particular expressions, as I will show with the modest example of the triangle proof of the combined horizontal and vertical countability of the real numbers, which I developed in rejection of Cantor’s diagonal proof. . 展开更多
关键词 Zeno False Assumptions about Motion Finitude INFINITY Cantor’s Diagonal Method Inverted Triangle as a Different Method Vertical and Horizontal Dimensions Quantum Theory Relativity of Space and Time Depending on Velocity
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Modelling of Time Dependency of Chloride Diffusion Coefficient in Cement Paste
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作者 张明中 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2010年第4期687-691,共5页
A computer-based model and method was presented to predict the time dependency of chloride diffusion coefficients in cement paste. The HYMOSTRUC3D model was applied to generate a 3D representative elementary volume (... A computer-based model and method was presented to predict the time dependency of chloride diffusion coefficients in cement paste. The HYMOSTRUC3D model was applied to generate a 3D representative elementary volume (REV) of cement paste. In the simulation of microstructure, both of cement hydration and chloride binding were considered. With the simulated microstructure of cement paste, the finite element method was applied to simulate the diffusion process of chloride through the saturated cement paste. Based on the Fick’s first law, the chloride diffusion coefficient can be calculated. In this method, the influences of age and w/c ratio on the chloride diffusion coefficient were evaluated. The simulated chloride diffusivities with various w/c at different time were compared to experimental data obtained from the literature. The experimental results indicate that the chloride diffusion coefficient decreases with the increase of time and the decrease of w/c ratio. The trend of simulated relationship (diffusion coefficient vs time, diffusion coefficient vs w/c ratio) fits very well with the experiments. 展开更多
关键词 cement paste time dependency chloride diffusion coefficient chloride binding HYMOSTRUC3D
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A Theoretical Study of Tris-(o-benzoquinonediimine)-First-Row Divalent Transition Metal Complexes
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作者 Mohammad Abdul Matin Samiran Bhattacharjee Anwar Hossain 《Advances in Chemical Engineering and Science》 CAS 2023年第2期172-188,共17页
The ligand o-phenylenediamine (opda) and its oxidized form, o-benzoquinonediimine (bqdi), act as a fascinating candidate coordinating toward transition metal ions leading to the photochemical hydrogen production in ab... The ligand o-phenylenediamine (opda) and its oxidized form, o-benzoquinonediimine (bqdi), act as a fascinating candidate coordinating toward transition metal ions leading to the photochemical hydrogen production in absence of photosensitizers. Herein, we report the systematic study of the interaction between the oxidized form bqdi ligand, tris-(o-benzoquinonediimine) with divalent first-row transition metal series using DFT calculations. The lowest energy structures, bond length, binding energies, frontier molecular orbital analysis, natural bond orbitals, and global reactivity descriptor were calculated using B3LYP/6-311G(d,P) level of theory. The time dependent-DFT at the CAM-B3LYP/6-311+G(d,p) level of theory was applied to determine the electronic structures and the optical spectra. The theoretical binding trend of the divalent first-row transition metal series is decreasing as follows: Cu >Ti > V > Co > Ni > Fe > Cr > Zn >Mn. Among them, the binding potency of iron (II) by the bqdi ligand was not predominantly sturdy as compared to other first-row divalent transition metal ions. The origin of strong coordination with Fe(II) is attributed to its extra capability to induce covalent coordination of bqdi ligands. The complex exhibited two strong peaks at 370 nm and 452 nm, due to the HOMO-3 to LUMO+1 and HOMO-1 to LUMO transitions, respectively. Natural bond orbital analysis showed that the major interaction happens between the N lone pair electrons of the ligand with an anti-bonding orbital of metal ions, in which Ti showed the highest interaction energy than other metal ions. The present systemic DFT study of bqdi ligands with the first-row transition metals strongly encourages the future establishment of photochemical hydrogen production in absence of photosensitizers. 展开更多
关键词 DFT O-PHENYLENEDIAMINE o-benzoquinodiimine First-Row Divalent Transition Metals Time Dependent–DFT Coordination Complexes
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Exploration of Traversable Wormholes Sustained by an Extra Spatial Dimension
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作者 Peter K. F. Kuhfittig 《International Journal of Astronomy and Astrophysics》 2023年第3期141-153,共13页
The main goal of this paper is to determine the effect of an extra dimension on a traversable wormhole. Here an earlier study by the author [Phys. Rev. D 98, 064041 (2018)] is extended in several significant ways. To ... The main goal of this paper is to determine the effect of an extra dimension on a traversable wormhole. Here an earlier study by the author [Phys. Rev. D 98, 064041 (2018)] is extended in several significant ways. To begin with, the extra spatial dimension is assumed to be time dependent, while the redshift and shape functions, as well as the extra dimension, are functions of both r and l, the respective radial and extra coordinates;the last of these is therefore a function of r, l, and t. The main objective is to determine the conditions that allow the throat of the wormhole to be threaded with ordinary matter (by respecting the null energy condition) and that the same conditions lead to a violation of the null energy condition in the fifth dimension, which is therefore responsible for sustaining the wormhole. The dependence of the extra dimension on l and t is subject to additional conditions that are subsequently analyzed in this paper. Finally, the extra dimension may be extremely small or even curled up. 展开更多
关键词 Traversable Wormholes Extra Spatial Dimension Time Dependence
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The Time and Regime Dependencies of Sensitive Areas for Tropical Cyclone Prediction Using the CNOP Method 被引量:11
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作者 周菲凡 穆穆 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2012年第4期705-716,共12页
This study examines the time and regime dependencies of sensitive areas identified by the conditional nonlinear optiflml perturbation (CNOP) method for forecasts of two typhoons. Typhoon Meari (2004) was weakly no... This study examines the time and regime dependencies of sensitive areas identified by the conditional nonlinear optiflml perturbation (CNOP) method for forecasts of two typhoons. Typhoon Meari (2004) was weakly nonlinear and is herein referred to as the linear case, while Typhoon Matsa (2005) was strongly nonlinear and is herein referred to as the nonlinear case. In the linear case, the sensitive areas identified for special forecast times when the initial time was fixed resembled those identified for other forecast times. Targeted observations deployed to improve a special time forecast would thus also benefit forecasts at other times. In the nonlinear case, the similarities among the sensitive areas identified for different forecast times were more limited. The deployment of targeted observations in the nonlinear case would therefore need to be adapted to achieve large improvements for different targeted forecasts. For both cases, the closer the forecast time, the higher the similarities of the sensitive areas. When the forecast time was fixed, the sensitive areas in the linear case diverged continuously from the verification area as the forecast period lengthened, while those in the nonlinear case were always located around the initial cyclones. The deployment of targeted observations to improve a special forecast depends strongly on the time of deployment. An examination of the efficiency gained by reducing initial errors within the identified sensitive areas confirmed these results. In general, the greatest improvement in a special time forecast was obtained by identifying the sensitive areas for the corresponding forecast time period. 展开更多
关键词 time dependence CNOP sensitive area TYPHOON targeted observations
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Multi-type ant system algorithm for the time dependent vehicle routing problem with time windows 被引量:14
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作者 DENG Ye ZHU Wanhong +1 位作者 LI Hongwei ZHENG Yonghui 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第3期625-638,共14页
The time dependent vehicle routing problem with time windows(TDVRPTW) is considered. A multi-type ant system(MTAS) algorithm hybridized with the ant colony system(ACS)and the max-min ant system(MMAS) algorithm... The time dependent vehicle routing problem with time windows(TDVRPTW) is considered. A multi-type ant system(MTAS) algorithm hybridized with the ant colony system(ACS)and the max-min ant system(MMAS) algorithms is proposed. This combination absorbs the merits of the two algorithms in solutions construction and optimization separately. In order to improve the efficiency of the insertion procedure, a nearest neighbor selection(NNS) mechanism, an insertion local search procedure and a local optimization procedure are specified in detail. And in order to find a balance between good scouting performance and fast convergence rate, an adaptive pheromone updating strategy is proposed in the MTAS. Computational results confirm the MTAS algorithm's good performance with all these strategies on classic vehicle routing problem with time windows(VRPTW) benchmark instances and the TDVRPTW instances, and some better results especially for the number of vehicles and travel times of the best solutions are obtained in comparison with the previous research. 展开更多
关键词 multi-type ant system(MTAS) time dependent vehicle routing problem with time windows(VRPTW) nearest neighbor selection(NNS)
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Numerical Simulation for Refraction-Diffraction of Waves in Water of Slowly Varying Current and Topography 被引量:5
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作者 Hong, GW Feng, WB +1 位作者 Xia, QY Pan, SH 《China Ocean Engineering》 SCIE EI 1997年第4期373-386,共14页
A new numerical finite difference iteration method for refraction-diffraction of waves ia water of slowly varying current and topography is developed in this paper. And corresponding theoretical model including the di... A new numerical finite difference iteration method for refraction-diffraction of waves ia water of slowly varying current and topography is developed in this paper. And corresponding theoretical model including the dissipation term is briefly described, together with some analysis and comparison of computational results of the model with measurements in a hydraulic scale model (Berkhoff et al., 1982). An example of practical use of the method is given, showing that the present model is useful to engineering practice. 展开更多
关键词 refraction-diffraction of waves on current wave number conservation wave action conservation Eikonal equation time dependent mild slope equation on current energy dissipation
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The Transport Properties of Concrete under the Simultaneous Coupling of Fatigue Load and Environment Factors 被引量:4
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作者 王彩辉 孙伟 +2 位作者 JING Jinyang HAN Jiande R0NG Hui 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2012年第1期181-186,共6页
A set of coupling experimental instrument was designed to study the transport properties of chloride ion in concrete under simultaneous coupling action of fatigue load and environmental factors. Firstly the water-satu... A set of coupling experimental instrument was designed to study the transport properties of chloride ion in concrete under simultaneous coupling action of fatigue load and environmental factors. Firstly the water-saturated performance of modem concrete was investigated, then diffusion performance of chloride ion under different stress levels and different temperature were studied respectively; meanwhile, the time- dependent behavior of the chloride ion diffusion in concrete was also researched. The results showed that the saturation degree of concrete can reach as high as 99%. Besides, diffusion coefficient of chloride ion increased with increasing of the stress level and temperature, and when the stress level and temperature are at 0.6 and 60 ℃ respectively, the diffusion coefficient is 6.3 ×10 -14 m2/s, moreover the diffusion coefficient of chloride ion in concrete decreased with time under the simultaneous coupling action of fatigue load and environment factors. 展开更多
关键词 chloride diffusion fatigue load CONCRETE stress level TEMPERATURE time dependent
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Uniaxial Time-Dependent Ratcheting of SS304 Stainless Steel at High Temperatures 被引量:4
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作者 KANG Guo-zheng ZHANG Juan SUN Ya-fang KAN Qian-hua 《Journal of Iron and Steel Research(International)》 SCIE EI CAS CSCD 2007年第1期53-59,共7页
The uniaxial time-dependent strain cyclic behaviors and ratcheting of SS304 stainless steel were studied at high temperatures (350 ℃ and 700 ℃). The effects of straining and stressing rates, holding time at the pe... The uniaxial time-dependent strain cyclic behaviors and ratcheting of SS304 stainless steel were studied at high temperatures (350 ℃ and 700 ℃). The effects of straining and stressing rates, holding time at the peak and/or valley of each cycle in addition to ambient temperature on the cyclic softening/hardening behavior and ratcheting of the material were discussed. It can be seen from experimental results that the material presents remarkable time dependence at 700 ℃, and the ratcheting strain depends greatly on the stressing rate, holding time and ambient temperature. Some significant conclusions are obtained, which are useful to build a constitutive model describiog the time-dependent cyclic deformation of the material. 展开更多
关键词 SS304 stainless steel time dependence RATCHETING high temperature
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Time Dependent Chloride Diffusion Coefficient in Concrete 被引量:4
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作者 宋鲁光 孙伟 GAO Jianming 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2013年第2期314-319,共6页
In order to study how to correctly apply the two different time dependencies to service life prediction models, the definition of parameters in the time dependent equation using the long-term test method and the short... In order to study how to correctly apply the two different time dependencies to service life prediction models, the definition of parameters in the time dependent equation using the long-term test method and the short-term test method, and its relationship were discussed. The experimental results show that, as the two time dependencies have different meanings, they have different manners when handled in service life prediction models. Time dependency of chloride diffusion coefficients in concrete was obtained by fitting experimental data. A large number of accurate experimental data were required to fit the formula of time dependency to ensure the accuracy of service life prediction model. 展开更多
关键词 CONCRETE time dependency chloride diffusion coefficient
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Pressure and Time Dependences of the Supercooled Liquid-to-Liquid Transition in Sulfur 被引量:1
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作者 张豆豆 刘秀茹 +1 位作者 何竹 洪时明 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第2期83-86,共4页
Thermal behavior of bulk amorphous sulfur is investigated by in situ temperature measurements at high pressures of 0.9, 1.4 and 2.1 GPa, and under different heating rates of 8, 10 and 12K/min at 0.9 GPa. The results s... Thermal behavior of bulk amorphous sulfur is investigated by in situ temperature measurements at high pressures of 0.9, 1.4 and 2.1 GPa, and under different heating rates of 8, 10 and 12K/min at 0.9 GPa. The results show that the onset temperature of the transition from the supercooled Hquid to the liquid state for sulfur increases with the pressure and the heating rate. It is deduced that the transition does not follow the Clapeyron equation, indicating considerable coupling of the molecular structure change in the transition. Along with the data at ambient pressure and high pressure, we present a dynamic diagram to demonstrate the relationship between the amorphous solid, supercooled liquid, liquid, and crystal phases of sulfur, and suggest an experimental approach to establish pressure-temperature-time transition diagrams for supercooled liquid and liquid. 展开更多
关键词 of on IT Pressure and Time Dependences of the Supercooled Liquid-to-Liquid Transition in Sulfur in that for IS
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A time-dependent measuring system for welding deformation 被引量:2
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作者 蔡志鹏 赵海燕 +2 位作者 鹿安理 史清宇 施光凯 《China Welding》 EI CAS 2002年第1期25-28,共4页
In this paper the establishment and application of a time dependent measuring system for welding deformation are presented which is established with high quality sensors shielded from strong welding interference. By ... In this paper the establishment and application of a time dependent measuring system for welding deformation are presented which is established with high quality sensors shielded from strong welding interference. By using this system, vertical and horizontal displacements of the high temperature area are surveyed at the same time. And this system is also used for monitoring and controlling the deformation of real welded structures. 展开更多
关键词 time dependent measuring system welding deformation
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Spectral Method for Solving Time Dependent Flow of Upper-Convected Maxwell Fluid in Tube 被引量:1
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作者 付强 张春雨 韩式方 《Journal of Modern Transportation》 2001年第2期130-137,共8页
The ti me dependent flow of upper-convected Maxwell fluid in a horizontal circular pip e is studied by spectral method. The time dependent problem is mathematically re duced to a partial differential equation of seco... The ti me dependent flow of upper-convected Maxwell fluid in a horizontal circular pip e is studied by spectral method. The time dependent problem is mathematically re duced to a partial differential equation of second order. By using spectral meth od the partial differential equation can be reduced to a system of ordinary diff erential equations for different terms of Chebyshev polynomials approximations. The ordinary differential equations are solved by Laplace transform and the eige nvalue method that leads to an analytical form of the solutions. 展开更多
关键词 spectral method time dependent flow Chebyshev polynomial
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A Path Integral Generalization of Bell Local Hidden Variable Models for Unstable Particles 被引量:2
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作者 Gianpaolo Bei 《Journal of Applied Mathematics and Physics》 2021年第10期2430-2438,共9页
We discuss the problem of the generalization of Bell local hidden variable models for unstable particles as nucleons or decaying quantum bound states. We propose to extend the formalism of real deterministic hidden va... We discuss the problem of the generalization of Bell local hidden variable models for unstable particles as nucleons or decaying quantum bound states. We propose to extend the formalism of real deterministic hidden variables in the complex domain, in analogy with the quantum Gamow ket formalism, and we introduce a time dependent classical probability density distribution by which we implement hidden time dependence in the quantum expectation values. We suggest therefore a classical framework which may recover by asymptotic temporal limits the standard Bell stationary quantum statistical averages. Endly we discuss the possible relevance of our proposal for general non-isolated quantum systems in noninertial frames and the consequent dynamic effects of vacuum instabilities on E.P.R tests and Q.M. ensemble statistical averages. 展开更多
关键词 Entangled Unstable Particles Complex Hidden Variables Path Dependent Expectation Values Time Dependent Bell Inequalities
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Alternative Approach to Time Evaluation of Schrodinger Wave Functions 被引量:1
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作者 Mustafa Erol 《Journal of Modern Physics》 2012年第11期1716-1721,共6页
Time evaluation of wave functions for any quantum mechanical system/particle is essential nevertheless quantum mechanical counterpart of the time dependant classical wave equation does simply not appear. Epistemologic... Time evaluation of wave functions for any quantum mechanical system/particle is essential nevertheless quantum mechanical counterpart of the time dependant classical wave equation does simply not appear. Epistemologically and ontologically considered time dependant momentum operator is initially defined and an Alternative Time Dependant Schrodinger Wave Equation (ATDSWE) is plainly derived. Consequent equation is primarily solved for the free particles, in a closed system, signifying a good agreement with the outcomes of the ordinary TDSWE. Free particle solution interestingly goes further possibly tracing some signs of new pathways to resolve the mysterious quantum world. 展开更多
关键词 Time Dependant Schrodinger Wave Equation Wave Function Evolution Quantum Theory Quantum Philosophy
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APPLICATION OF Ct-PARAMETER FOR CREEP-FATIGUE CRACK GROWTH WITH SLOW LOAD RISING CONDITION
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作者 Lee, J.H. Yoon, K.B. +1 位作者 Kim, Y.J. Back, U.B. 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1999年第1期22-30,共9页
Most of the assessment equations for Ct which is a wellknown fracture parameter characterizing high temperature crack growth rates, have limited applicability to constant load conditions after sudden loading. However... Most of the assessment equations for Ct which is a wellknown fracture parameter characterizing high temperature crack growth rates, have limited applicability to constant load conditions after sudden loading. However, crack growth due to creep can also occur under load varying conditions when load rising time is so long that accumulated creep deformation near the crack tip is not negligible.In this paper, the estimation equation of the Ctparameter which can be applied to the case of slow load rising, i.e., (Ct)r, is explained. And the correlation between (Ct)r at the end of the load increasing period and Ct at the beginning of the succeeding load hold period is discussed. Finite element analyses of several cases with various loading conditions were performed and results were presented to show the effectiveness of the proposed Ct estimation scheme. The general applicability of the equation is also discussed. 展开更多
关键词 creep fatigue CRACK time dependent fracture mechanics Ctparameter C*integral
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Influence of Neodymium on Amorphizability of RS Al-Fe-V-Si-Nd Alloys:An Investigation Using Time Dependent Nucleation Theory
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作者 庞华 郑立净 +1 位作者 张宝金 曾梅光 《Journal of Rare Earths》 SCIE EI CAS CSCD 2000年第4期293-297,共5页
Time dependent nucleation theory was applied to calculate the incubation time required for α Al nucleation in rapid solidified (RS) Al Fe V Si Nd alloys. The nucleation rates were calculated as a function of tem... Time dependent nucleation theory was applied to calculate the incubation time required for α Al nucleation in rapid solidified (RS) Al Fe V Si Nd alloys. The nucleation rates were calculated as a function of temperature, and the critical cooling rates required for the formation of amorphous α Al at different neodymium concentrations were calculated too. The addition of neodymium increases the amorphizablity of α Al by increasing the incubation time and decreasing the nucleation rate and the critical cooling rate. The calculations are fitted to experimental results when liquidus temperatures are estimated from an approximation, which treats Al Fe V Si Nd as quasi binary Al Fe system. 展开更多
关键词 rare earths NEODYMIUM amorphizablity Al Fe V Si Nd alloys time dependent nucleation theory rapid solidified processi?
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Numerical Simulation of ATPS Parachute Transient Dynamics Using Fluid-Structure Interaction Method
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作者 Fan Yuxin Xia Jian 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2017年第5期535-542,共8页
In order to simulate and analyze the dynamic characteristics of the parachute from advanced tactical parachute system(ATPS),a nonlinear finite element algorithm and a preconditioning finite volume method are employed ... In order to simulate and analyze the dynamic characteristics of the parachute from advanced tactical parachute system(ATPS),a nonlinear finite element algorithm and a preconditioning finite volume method are employed and developed to construct three dimensional parachute fluid-structure interaction(FSI)model.Parachute fabric material is represented by membrane-cable elements,and geometrical nonlinear algorithm is employed with wrinkling technique embedded to simulate the large deformations of parachute structure by applying the NewtonRaphson iteration method.On the other hand,the time-dependent flow surrounding parachute canopy is simulated using preconditioned lower-upper symmetric Gauss-Seidel(LU-SGS)method.The pseudo solid dynamic mesh algorithm is employed to update the flow-field mesh based on the complex and arbitrary motion of parachute canopy.Due to the large amount of computation during the FSI simulation,massage passing interface(MPI)parallel computation technique is used for all those three modules to improve the performance of the FSI code.The FSI method is tested to simulate one kind of ATPS parachutes to predict the parachute configuration and anticipate the parachute descent speeds.The comparison of results between the proposed method and those in literatures demonstrates the method to be a useful tool for parachute designers. 展开更多
关键词 parachute dynamics fluid-structure interaction nonlinear structure dynamics time dependent flow parallel computation technique
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Electron localization of H_2^+ in a dc electric field
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作者 贾正茂 曾志男 +1 位作者 唐文涛 李儒新 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第1期170-175,共6页
A dc electric field is utilized to steer the electron motion after the molecular ion H2-+ is excited by an ultrashort ultraviolet laser pulse. The numerical simulation shows that the electron localization distributio... A dc electric field is utilized to steer the electron motion after the molecular ion H2-+ is excited by an ultrashort ultraviolet laser pulse. The numerical simulation shows that the electron localization distribution and the dissociation control ratio are dependent on the polarization direction and amplitude of the dc electric field. Most electrons of the dissociation state move opposite to the dc electric field and stabilize at the dressed-up potential well, for the dressed-down well is occupied by the electrons of the 1 sσg state. 展开更多
关键词 dissociation localization time dependent Schrdinger equation Coulomb potential ultraviolet laser pulse
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