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Quantum generative adversarial networks based on a readout error mitigation method with fault tolerant mechanism
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作者 赵润盛 马鸿洋 +2 位作者 程涛 王爽 范兴奎 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期285-295,共11页
Readout errors caused by measurement noise are a significant source of errors in quantum circuits,which severely affect the output results and are an urgent problem to be solved in noisy-intermediate scale quantum(NIS... Readout errors caused by measurement noise are a significant source of errors in quantum circuits,which severely affect the output results and are an urgent problem to be solved in noisy-intermediate scale quantum(NISQ)computing.In this paper,we use the bit-flip averaging(BFA)method to mitigate frequent readout errors in quantum generative adversarial networks(QGAN)for image generation,which simplifies the response matrix structure by averaging the qubits for each random bit-flip in advance,successfully solving problems with high cost of measurement for traditional error mitigation methods.Our experiments were simulated in Qiskit using the handwritten digit image recognition dataset under the BFA-based method,the Kullback-Leibler(KL)divergence of the generated images converges to 0.04,0.05,and 0.1 for readout error probabilities of p=0.01,p=0.05,and p=0.1,respectively.Additionally,by evaluating the fidelity of the quantum states representing the images,we observe average fidelity values of 0.97,0.96,and 0.95 for the three readout error probabilities,respectively.These results demonstrate the robustness of the model in mitigating readout errors and provide a highly fault tolerant mechanism for image generation models. 展开更多
关键词 readout errors quantum generative adversarial networks bit-flip averaging method fault tolerant mechanisms
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Unsupervised multi-modal image translation based on the squeeze-and-excitation mechanism and feature attention module
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作者 胡振涛 HU Chonghao +1 位作者 YANG Haoran SHUAI Weiwei 《High Technology Letters》 EI CAS 2024年第1期23-30,共8页
The unsupervised multi-modal image translation is an emerging domain of computer vision whose goal is to transform an image from the source domain into many diverse styles in the target domain.However,the multi-genera... The unsupervised multi-modal image translation is an emerging domain of computer vision whose goal is to transform an image from the source domain into many diverse styles in the target domain.However,the multi-generator mechanism is employed among the advanced approaches available to model different domain mappings,which results in inefficient training of neural networks and pattern collapse,leading to inefficient generation of image diversity.To address this issue,this paper introduces a multi-modal unsupervised image translation framework that uses a generator to perform multi-modal image translation.Specifically,firstly,the domain code is introduced in this paper to explicitly control the different generation tasks.Secondly,this paper brings in the squeeze-and-excitation(SE)mechanism and feature attention(FA)module.Finally,the model integrates multiple optimization objectives to ensure efficient multi-modal translation.This paper performs qualitative and quantitative experiments on multiple non-paired benchmark image translation datasets while demonstrating the benefits of the proposed method over existing technologies.Overall,experimental results have shown that the proposed method is versatile and scalable. 展开更多
关键词 multi-modal image translation generative adversarial network(GAN) squeezeand-excitation(SE)mechanism feature attention(FA)module
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New Approach to Synchronize General Relativity and Quantum Mechanics with Constant “K”-Resulting Dark Matter as a New Fundamental Force Particle
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作者 Siva Prasad Kodukula 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第1期292-302,共11页
Planck scale plays a vital role in describing fundamental forces. Space time describes strength of fundamental force. In this paper, Einstein’s general relativity equation has been described in terms of contraction a... Planck scale plays a vital role in describing fundamental forces. Space time describes strength of fundamental force. In this paper, Einstein’s general relativity equation has been described in terms of contraction and expansion forces of space time. According to this, the space time with Planck diameter is a flat space time. This is the only diameter of space time that can be used as signal transformation in special relativity. This space time diameter defines the fundamental force which belongs to that space time. In quantum mechanics, this space time diameter is only the quantum of space which belongs to that particular fundamental force. Einstein’s general relativity equation and Planck parameters of quantum mechanics have been written in terms of equations containing a constant “K”, thus found a new equation for transformation of general relativity space time in to quantum space time. In this process of synchronization, there is a possibility of a new fundamental force between electromagnetic and gravitational forces with Planck length as its space time diameter. It is proposed that dark matter is that fundamental force carrying particle. By grand unification equation with space-time diameter, we found a coupling constant as per standard model “α<sub>s</sub>” for that fundamental force is 1.08 × 10<sup>-23</sup>. Its energy calculated as 113 MeV. A group of experimental scientists reported the energy of dark matter particle as 17 MeV. Thorough review may advance science further. 展开更多
关键词 general Relativity Quantum mechanics Space Time Dark Matter A New Fundamental Constant “K”
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Quantum Chemical Studies on the Mechanism of Producing Oxygenates in Fischer-Tropsch Synthesis on M/SiO2(M = Ni,Ru,Rh,Pd)
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作者 ZHU Tian-wei and HAO Zheng-ping (Department of Chemistry,Inner Mongolia Normal University,Huhehote,010022) Lanzhou Institute of Chemical Physics 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 1995年第2期122-130,共9页
EHMO calculations and orbital analyses of fragment;;have been performed for the formation of oxygenates in Fischer-Tropsch synthesis on the butterfly model for four different metal (Ni,Ru,Rh,Pd) catalysts supported on... EHMO calculations and orbital analyses of fragment;;have been performed for the formation of oxygenates in Fischer-Tropsch synthesis on the butterfly model for four different metal (Ni,Ru,Rh,Pd) catalysts supported on SiO2.Calculations were made for the four processes,i.e.,CO-dissociation;Coupling of CO and H to produce CHO;Insertion of CO to M-CH3;insertion of CH2 to M-CH3 On the basis of comparing the degree of CO bonds activation and the energy barriers of the foregoing processes for these four catalysts,it is concluded that Ni/SiO2 can be used as the methanation catalyst.On Ru/SiO2 and Rh/SiO2 C2-oxygenated compound can be produced (acetaldehyde),especially Rh/SiO2 is the even better catalyst,and Pd/SiO2 is a methanol synthesis catalyst. 展开更多
关键词 EHMO calculation Fischer-Tropsch synthesis mechanism of producing oxygenates Group VIII supported metal catalysts
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Mechanism of generation of large(Ti,Nb,V)(C,N)-type precipitates in H13 + Nb tool steel 被引量:4
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作者 You Xie Guo-guang Cheng +2 位作者 Lie Chen Yan-dong Zhang Qing-zhong Yan 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2016年第11期1264-1274,共11页
The characteristics and generation mechanism of(Ti,Nb,V)(C,N) precipitates larger than 2 μm in Nb-containing H13 bar steel were studied. The results show that two types of(Ti,Nb,V)(C,N) phases exist—a Ti-V-r... The characteristics and generation mechanism of(Ti,Nb,V)(C,N) precipitates larger than 2 μm in Nb-containing H13 bar steel were studied. The results show that two types of(Ti,Nb,V)(C,N) phases exist—a Ti-V-rich one and an Nb-rich one—in the form of single or complex precipitates. The sizes of the single Ti-V-rich(Ti,Nb,V)(C,N) precipitates are mostly within 5 to 10 μm, whereas the sizes of the single Nb-rich precipitates are mostly 2–5 μm. The complex precipitates are larger and contain an inner Ti-V-rich layer and an outer Nb-rich layer. The compositional distribution of(Ti,Nb,V)(C,N) is concentrated. The average composition of the single Ti-V-rich phase is(Ti_(0.511)V_(0.356)Nb_(0.133))(CxNy), whereas that for the single Nb-rich phase is(Ti_(0.061)V_(0.263)Nb_(0.676))(C_xN_y). The calculation results based on the Scheil–Gulliver model in the Thermo-Calc software combining with the thermal stability experiments show that the large phases precipitate during the solidification process. With the development of solidification, the Ti-V-rich phase precipitates first and becomes homogeneous during the subsequent temperature reduction and heat treatment processes. The Nb-rich phase appears later. 展开更多
关键词 precipitates carbonitrides generating mechanism tool steel niobium
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Exploring unbinding mechanism of drugs from SERT via molecular dynamics simulation and its implication in antidepressants
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作者 谭新官 刘雪峰 +2 位作者 庞铭慧 王雨晴 赵蕴杰 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第8期510-519,共10页
The human serotonin transporter(SERT)terminates neurotransmission by removing serotonin from the synaptic cleft,which is an essential process that plays an important role in depression.In addition to natural substrate... The human serotonin transporter(SERT)terminates neurotransmission by removing serotonin from the synaptic cleft,which is an essential process that plays an important role in depression.In addition to natural substrate serotonin,SERT is also the target of the abused drug cocaine and,clinically used antidepressants,escitalopram,and paroxetine.To date,few studies have attempted to investigate the unbinding mechanism underlying the orthosteric and allosteric modulation of SERT.In this article,the conserved property of the orthosteric and allosteric sites(S1 and S2)of SERT was revealed by combining the high resolutions of x-ray crystal structures and molecular dynamics(MD)simulations.The residues Tyr95 and Ser438 located within the S1 site,and Arg104 located within the S2 site in SERT illustrate conserved interactions(hydrogen bonds and hydrophobic interactions),as responses to selective serotonin reuptake inhibitors.Van der Waals interactions were keys to designing effective drugs inhibiting SERT and further,electrostatic interactions highlighted escitalopram as a potent antidepressant.We found that cocaine,escitalopram,and paroxetine,whether the S1 site or the S2 site,were more competitive.According to this potential of mean force(PMF)simulations,the new insights reveal the principles of competitive inhibitors that lengths of trails from central SERT to an opening were~18A for serotonin and~22 A for the above-mentioned three drugs.Furthermore,the distance between the natural substrate serotonin and cocaine(or escitalopram)at the allosteric site was~3A.Thus,it can be inferred that the potent antidepressants tended to bind at deeper positions of the S1 or the S2 site of SERT in comparison to the substrate.Continuing exploring the processes of unbinding four ligands against the two target pockets of SERT,this study observed a broad pathway in which serotonin,cocaine,escitalopram(at the S1 site),and paroxetine all were pulled out to an opening between MT1b and MT6a,which may be helpful to understand the dissociation mechanism of antidepressants. 展开更多
关键词 human serotonin transporter(SERT) comprehensive molecular dynamics(MD)simulation drug design molecular mechanics/generalized Born surface area(MM/GBSA)method
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Novel Mobility Formula for Parallel Mechanisms Expressed with Mobility of General Link Group 被引量:14
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作者 ZHANG Yitong LU Wenjuan +3 位作者 MU Dejun YANG Yandong ZHANG Lijie ZENG Daxing 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第6期1082-1090,共9页
The determination of virtual constraints is always one of the key and difficult problems in traditional mobility calculation. To make mobility calculation simple, considering avoiding virtual constraints, some new for... The determination of virtual constraints is always one of the key and difficult problems in traditional mobility calculation. To make mobility calculation simple, considering avoiding virtual constraints, some new formulae have been presented, however these formulae can hardly intuitively reflect general link group's restrictions on output member and its influences on independence of output parameters, which is premise to the judgment of the properties of mobility. Towards the problem to reveal the intrinsic relationship between the degree of freedom(DOF) of a mechanism, the link group, and the dimension of output parameters, also to avoid determination of virtual constraint, based on the new concepts of the "DOF of general link group" and "node parameters", a new formula in the calculation of the mobility of mechanisms is presented that is expressed with DOFs of the general link groups and rank of motion parameters of base point of the output link. It is named GOM(mobility of groups and output parameter) formula. On the basis of new concepts of"effective parameters" and "invalid parameters", a rule is put forward for solving the DOF of mechanisms with invalid parameters by GOM formula, that is, the base point parameters are the subset of effective parameters of link group. Thereafter, several examples are enumerated and the results coincide with the prototype data, which proves the validity of the proposed formula. Meanwhile, it is obtained that the necessary and sufficient condition for the judgment of output parameters independence is that each of the DOF of the link group is not less than zero. The proposed formula which is simple in calculation provides theoretical basis for the judgment of independence of output parameters and provides references for type synthesis of novel parallel mechanisms with independence requirements of their output parameters. 展开更多
关键词 parallel mechanism degree of freedom general link group output parameters
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Analysis on produce mechanism and influence factor of CO gas on the coal exploitation working face 被引量:1
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作者 邓军 蒋志刚 肖蕾 《Journal of Coal Science & Engineering(China)》 2008年第3期432-435,共4页
Summarized the four main sources of CO gas on the working face based on investigation and local observation: firstly,it analyzed the mechanism that CO gas was produced by spontaneous combustion and oxygenation of gob ... Summarized the four main sources of CO gas on the working face based on investigation and local observation: firstly,it analyzed the mechanism that CO gas was produced by spontaneous combustion and oxygenation of gob residual coal;next,it illus- trated the theory that special coal seam deposits natural CO gas,and provided correlative experiment data;and then,it illustrated the reason of the CO gas in working face in- creased relatively in the course of coal cutter's shearing,according to the translation be- tween mechanism energy and inner energy and the rupture of carbon molecule side chain during coal exploitation;lastly,illustrated the reason of CO gas appearance and the rela- tively release quantity during coal mine blasting underground.We find out the source of CO gas on the working face accurately,and provide advantages for appropriate prevention and practical management measures. 展开更多
关键词 煤炭开采面 一氧化碳 矿山安全 机械故障
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Multi-distortion suppression for neutron radiographic images based on generative adversarial network
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作者 Cheng-Bo Meng Wang-Wei Zhu +4 位作者 Zhen Zhang Zi-Tong Wang Chen-Yi Zhao Shuang Qiao Tian Zhang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第4期176-188,共13页
Neutron radiography is a crucial nondestructive testing technology widely used in the aerospace,military,and nuclear industries.However,because of the physical limitations of neutron sources and collimators,the result... Neutron radiography is a crucial nondestructive testing technology widely used in the aerospace,military,and nuclear industries.However,because of the physical limitations of neutron sources and collimators,the resulting neutron radiographic images inevitably exhibit multiple distortions,including noise,geometric unsharpness,and white spots.Furthermore,these distortions are particularly significant in compact neutron radiography systems with low neutron fluxes.Therefore,in this study,we devised a multi-distortion suppression network that employs a modified generative adversarial network to improve the quality of degraded neutron radiographic images.Real neutron radiographic image datasets with various types and levels of distortion were built for the first time as multi-distortion suppression datasets.Thereafter,the coordinate attention mechanism was incorporated into the backbone network to augment the capability of the proposed network to learn the abstract relationship between ideally clear and degraded images.Extensive experiments were performed;the results show that the proposed method can effectively suppress multiple distortions in real neutron radiographic images and achieve state-of-theart perceptual visual quality,thus demonstrating its application potential in neutron radiography. 展开更多
关键词 Neutron radiography Multi-distortion suppression generative adversarial network Coordinate attention mechanism
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Generating Electricity from Mechanical Vibrations:Optimization of Linear a Generator 被引量:2
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作者 MAA KARUNARATHNA KAM DHANURANGA 《Instrumentation》 2021年第2期34-39,共6页
Energy preservation is one of the key components in developing eco-friendly machines.In industry,the majority of machines lose a considerable amount of energy through mechanical vibrations.However,the wasted energy th... Energy preservation is one of the key components in developing eco-friendly machines.In industry,the majority of machines lose a considerable amount of energy through mechanical vibrations.However,the wasted energy through vibration can be utilized as a renewable energy source to compensate for the overall energy loss.The research work presented in this paper discusses the ability to design a linear power generator utilizing Nd Fe-B magnets,which can generate energy through mechanical vibrations.A pilot model was developed and simulated to understand the efficiency and limitation.The results showed that the model could reduce 14% rotor bulk with a marginal impact on the current generation. 展开更多
关键词 mechanical Vibrations Linear generator Sustainable Energy Energy production
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EXPERIMENTAL INVESTIGATION ON GENERATION MECHANISM OF EXPLOSIVE STRESS WAVES 被引量:2
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作者 Xu, Guoyuan Gu, Desheng 《中国有色金属学会会刊:英文版》 EI CSCD 1999年第2期229-232,共4页
1INTRODUCTIONExplosivestresswavesarequiteimportantinrockfragmentationproces.Manyscholarshaveinvestigatedtheg... 1INTRODUCTIONExplosivestresswavesarequiteimportantinrockfragmentationproces.Manyscholarshaveinvestigatedthegenerationandpropa... 展开更多
关键词 generATION mechanism of EXPLOSIVE STRESS wavesshock energybubble energy
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RELIABILITY-BASED ANALYSIS AND SYNTHESIS OF MECHANICAL ERROR FOR PATH GENERATING LINKAGES 被引量:15
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作者 Shi Zhongxiu ,Li FengqiangQingdao University 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 1997年第2期130-135,共3页
A reliability-based analysis approach to mechanical error in path generating linkages is pre- sented . The reliability index is taken as a measure for the deviation of the actual path of a coupler point from the desir... A reliability-based analysis approach to mechanical error in path generating linkages is pre- sented . The reliability index is taken as a measure for the deviation of the actual path of a coupler point from the desired one. A reliability-based synthesis procedure of the mechanical error for path generating linkages to allocate optimal tolerances and clearances is developed. A four-bar path generating mechanism is considered for numerical illustration. 展开更多
关键词 Four-bar mechanism Path generating mechanism RELIABILITY SYNTHESIS
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Status of research on biogenic coalbed gas generation mechanisms 被引量:7
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作者 WANG, Aikuan QIN, Yong +1 位作者 WU, Yanyan WANG, Baowen 《Mining Science and Technology》 EI CAS 2010年第2期271-275,共5页
Biogenic coalbed gas,how it is generated and the geochemical characteristics of the gas are gaining global attention.The ways coalbed gas is generated,the status of research on the generation mechanism and the methods... Biogenic coalbed gas,how it is generated and the geochemical characteristics of the gas are gaining global attention.The ways coalbed gas is generated,the status of research on the generation mechanism and the methods of differentiating between biogenic gasses are discussed.The generation of biogenic coalbed methane is consistent with anaerobic fermentation theory.Commercial biogenic coalbed gas reservoirs are mainly generated by the process of CO2 reduction.The substrates used by the microbes living in the coal include organic compounds,CO2,H2 and acetate.The production ratio and quantity of biogenic coalbed methane depend on the exposed surface area,the solubility and permeability of the coal and the microbial concentration in the coal seam.It is generally believed that biogenic coalbed gas has a value for δ13C1<-5.5%,C1/C1+>0.95.The H isotope ratio is controlled by both the environment and the generation mechanism:typically δD1<-20%.Biogenic methane formed by CO2 reduction has more δD1 than that formed by acetate fermentation. 展开更多
关键词 coalbed gas biogenic coalbed gas secondary biogenic coalbed gas generation mechanism DISCRIMINATION
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STUDY OF REGULARITY OF GENERAL-LINEAR-COMPLEX SINGULARITY OF 3/6-STEWART MECHANISM 被引量:1
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作者 Li Yanwen Huang ZhenRobotics research Center,Yanshan University,Qinhuangdao 066004, China 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2003年第3期325-328,共4页
The general-linear-complex singularity of Stewart mechanism is a veryimportant problem in the parallel manipulator. Its general regularity is not found yet during thepast two decades. St-Onge and Gosselin pointed Out ... The general-linear-complex singularity of Stewart mechanism is a veryimportant problem in the parallel manipulator. Its general regularity is not found yet during thepast two decades. St-Onge and Gosselin pointed Out that the singularity locus of the Stewartmechanism at some given orientations of the moving platform should be polynomial expressions withvaried degrees in 2000, but they didn't formulate the expression. Based on the kinematicssingularity principle and the geometry condition proposed by Huang Zhen in 1999, firstly thesingularity equation in degree two is derived. It is a hyperbola when the orientation of the movingplatform is given. This result is also proved using screw theory. Then some singularity surfaces aregotten in three-dimensional space. This result is of important significance. 展开更多
关键词 Stewart mechanism general-linear-complex Singular configuration
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AN INVESTIGATION ON THE INTERACTION MECHANISM OF β-CAROTENE WITH HALOGEN ATOM PRODUCED IN HALOBENZENE BY UV IRRADIATION
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作者 Yong LI Bing SHI Qing Gui SHA Department of Chemistry,Tsinghua University,Beijing,100084 《Chinese Chemical Letters》 SCIE CAS CSCD 1990年第3期197-200,共4页
ESR measurements using spin trapping technique were carried out for β-carotene-halobenzene system under UV light irradiation.The ESR spectra observed in the presence and in the absence of β-carotene are markedly dif... ESR measurements using spin trapping technique were carried out for β-carotene-halobenzene system under UV light irradiation.The ESR spectra observed in the presence and in the absence of β-carotene are markedly different.The possible scheme of β-carotene interacting with halogen atom was proposed. 展开更多
关键词 ESR AN INVESTIGATION ON THE INTERACTION mechanism OF CAROTENE WITH HALOGEN ATOM producED IN HALOBENZENE BY UV IRRADIATION UV
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Algebraic Solution for the Forward Displacement Analysis of the General 6-6 Stewart Mechanism 被引量:8
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作者 WEI Feng WEI Shimin +1 位作者 ZHANG Ying LIAO Qizheng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第1期56-62,共7页
The solution for the forward displacement analysis(FDA) of the general 6-6 Stewart mechanism(i.e., the connection points of the moving and fixed platforms are not restricted to lying in a plane) has been extensive... The solution for the forward displacement analysis(FDA) of the general 6-6 Stewart mechanism(i.e., the connection points of the moving and fixed platforms are not restricted to lying in a plane) has been extensively studied, but the efficiency of the solution remains to be effectively addressed. To this end, an algebraic elimination method is proposed for the FDA of the general 6-6 Stewart mechanism. The kinematic constraint equations are built using conformal geometric algebra(CGA). The kinematic constraint equations are transformed by a substitution of variables into seven equations with seven unknown variables. According to the characteristic of anti-symmetric matrices, the aforementioned seven equations can be further transformed into seven equations with four unknown variables by a substitution of variables using the Grobner basis. Its elimination weight is increased through changing the degree of one variable, and sixteen equations with four unknown variables can be obtained using the Grobner basis. A 40th-degree univariate polynomial equation is derived by constructing a relatively small-sized 9 × 9 Sylvester resultant matrix. Finally, two numerical examples are employed to verify the proposed method. The results indicate that the proposed method can effectively improve the efficiency of solution and reduce the computational burden because of the small-sized resultant matrix. 展开更多
关键词 general 6-6 Stewart mechanism forward displacement analysis (FDA) conformal geometric algebra (CGA) Gr6bner basis Sylvester resultant
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Plasma Simulation of Dielectric-lined Multiwave Cerenkov Generators Producing High Power Millimeter Waves
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作者 舒挺 刘永贵 《Plasma Science and Technology》 SCIE EI CAS CSCD 2000年第2期181-186,共6页
This paper presents the concept of a Dielectric-lined Multiwave Cerenkov Generator producing high power millimeter waves, which has been investigated with a two and onehalf dimensional electromagnetic relativistic Par... This paper presents the concept of a Dielectric-lined Multiwave Cerenkov Generator producing high power millimeter waves, which has been investigated with a two and onehalf dimensional electromagnetic relativistic Particle-in-Cell (PIC) plasma simulation code. Themodified device can operate in a lower diode-voltage regime with much higher radiation efficiencyand slight downshift of operation frequency. There exist the optima for the permittivity of thedielectric liner and for the magnitude of the guiding magnetic field. The required intensity of theguiding field is reduced by the introduction of the liner. The enhanced propagation of the electronbeam is studied in the presence of the liner. 展开更多
关键词 CM Plasma Simulation of Dielectric-lined Multiwave Cerenkov generators producing High Power Millimeter Waves
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Analysis on Physical Mechanism of Sound Generation inside Cavities Based on Acoustic Analogy Method 被引量:6
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作者 Dangguo Yang Jianqiang Li +2 位作者 Jun Liu Yi Zhang Yaohua Li 《Open Journal of Fluid Dynamics》 2013年第1期23-31,共9页
Analysis of coupling aerodynamics and acoustics are performed to investigate the self-sustained oscillation and aerodynamic noise in two-dimensional flow past a cavity with length to depth ratio of 2 at subsonic speed... Analysis of coupling aerodynamics and acoustics are performed to investigate the self-sustained oscillation and aerodynamic noise in two-dimensional flow past a cavity with length to depth ratio of 2 at subsonic speeds. The large eddy simulation (LES) equations and integral formulation of Ffowcs-Williams and Hawings (FW-H) are solved for the cavity with same conditions as experiments. The obtained density-field agrees well with Krishnamurty’s experimental schlieren photograph, which simulates flow-field distributions and the direction of sound wave radiation. The simulated self-sustained oscillation modes inside the cavity agree with Rossiter’s and Heller’s predicated results, which indicate frequency characteristics are obtained. Moreover, the results indicate that the feedback mechanism that new shedding-vortexes induced by propagation of sound wave created by the impingement of the shedding-vortexes in the shear-layer and rear cavity face leads to self-sustained oscillation and high noise inside the cavity. The peak acoustic pressure occurs in the first oscillation mode and the most of sound energy focuses on the low-frequency region. 展开更多
关键词 CAVITY Physical mechanism SOUND generation Aerodynamic Noise SOUND PRESSURE Level SOUND PRESSURE Frequency SPECTRUM
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Continuum Mechanics of Space Seen from the Aspect of General Relativity An Interpretation of the Gravity Mechanism 被引量:1
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作者 Yoshinari Minami 《Journal of Earth Science and Engineering》 2015年第3期188-202,共15页
关键词 连续介质力学 假设空间 广义相对论 Riemann几何 机械结构 精细结构 几何结构 压力场
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Mathematical Model and Geometrical Model of Double Pitch ZN-type Worm Gear Set Based on Generation Mechanism 被引量:2
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作者 SHU Linsen CAO Huajun +2 位作者 LI Xianchong ZHANG Chenglong LI Yuxia 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第3期549-555,共7页
The current researches on the tooth surface mathematical equations and the theory of gearing mainly pay attention to the ordinary type worm gear set(e.g., ZN, ZA, or ZK). The research of forming mechanism and three-... The current researches on the tooth surface mathematical equations and the theory of gearing mainly pay attention to the ordinary type worm gear set(e.g., ZN, ZA, or ZK). The research of forming mechanism and three-dimensional modeling method for the double pitch worm gear set is not enough. So there are some difficulties in mathematical model deducing and geometry modeling of double pitch ZN-type worm gear set based on generation mechanism. In order to establish the mathematical model and the precise geometric model of double pitch ZN-type worm gear set, the structural characteristics and generation mechanism of the double pitch ZN-type worm gear set are investigated. Mathematical model of the ZN-type worm gear set is derived based on its generation mechanism and the theory of gearing. According to the mathematical model of the worm gear set which has been developed, a geometry modeling method of the double pitch ZN-type worm and worm gear is presented. Furthermore, a geometrical precision calculate method is proposed to evaluate the geometrical quality of the double pitch worm gear set. As a result, the maximum error is less than 6′10–4 mm in magnitude, thus the model of the double pitch ZN-type worm gear set is available to meet the requirements of finite element analysis and engineering application. The derived mathematical model and the proposed geometrical modeling method are helpful to guiding the design, manufacture and contact analysis of the worm gear set. 展开更多
关键词 double pitch ZN-type worm gear set generation mechanism mathematical model geometrical model
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