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Observation of Doppler shift f_(D) modulated by the internal kink mode using conventional reflectometry in the EAST tokamak
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作者 李恭顺 张涛 +18 位作者 耿康宁 文斐 叶凯萱 徐立清 朱翔 张学习 钟富彬 周振 杨书琪 周子强 喻琳 兰婷 王守信 提昂 张寿彪 刘海庆 李国强 高翔 the EAST Team 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第3期1-9,共9页
In this paper we present a new experimental observation using a conventional reflectometry technique,poloidal correlation reflectometry(PCR),in the Experimental Advanced Superconducting Tokamak(EAST).The turbulence sp... In this paper we present a new experimental observation using a conventional reflectometry technique,poloidal correlation reflectometry(PCR),in the Experimental Advanced Superconducting Tokamak(EAST).The turbulence spectrum detected by the PCR system exhibits an asymmetry and induced Doppler shift f_(D)during the internal kink mode(IKM)rotation phase.This Doppler shift f_(D)is the target measurement of Doppler reflectometry,but captured by conventional reflectometry.Results show that the Doppler shift f_(D)is modulated by the periodic changes in the effective angle between the probing wave and cutoff layer normal,but not by plasma turbulence.The fishbone mode and saturated long-lived mode are typical IKMs,and this modulation phenomenon is observed in both cases.Moreover,the value of the Doppler shift f_(D)is positively correlated with the amplitude of the IKM,even when the latter is small.However,the positive and negative frequency components of the Doppler shift f_(D)can be asymmetric,which is related to the plasma configuration.A simulated analysis is performed by ray tracing to verify these observations.These results establish a clear link between f_(D)and IKM rotation,and are helpful for studying the characteristics of IKM and related physical phenomena. 展开更多
关键词 microwave reflectometry doppler shift internal kink mode
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The Difference in Mass between Relativity and Quantum Mechanics, Also Novel Effects of the Axial Doppler Shift
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作者 Samuel Lewis Reich Winston G. Perera 《Journal of High Energy Physics, Gravitation and Cosmology》 2019年第3期629-637,共9页
If a particle has a wave function or is in other ways a moving wave, it should have an axial Doppler shift. Writers on relativity do not give moving particles that. The classic equation of quantum mechanics requires t... If a particle has a wave function or is in other ways a moving wave, it should have an axial Doppler shift. Writers on relativity do not give moving particles that. The classic equation of quantum mechanics requires that frequency and mass have the same distortion from velocity (Doppler shift). But in the common writings on relativity mass always goes up with increases of velocity, and the transverse shift of frequency always goes down with increases of velocity [1] [2] [3] [4]. Most of this is due to simplifications and errors in the Lorentz transformation, some came from being in the aether wind era originally and because accelerators are noisy. It is not valid to say because the aether axial wind averages to zero between reflections so does axial Doppler shifts. After the first reflection in the Lorentz transformation, the light from the Sun is in Earth’s reference frame and there are no more Doppler shifts. Also the Michelson-Morley experiment is not all cases, and light is not the only thing deformed by velocity. The axial shift’s formula has the cosine of the observation angle in it. The implications are not just quantitative but also qualitative because anything with an axial Doppler shift has different values in different directions from an observer. That is the defining property of a vector and that changes its dimensions and the dimensions of the differential relations it is in. This happens with other scalar qualities as well. That means scalars such as mass and charge are now vectors and have additional dimensions. Therefore differential equations with them have additional dimensions. This includes Faraday-Max- well’s equations and Schrodinger’s equations. Also the Doppler blue shift seems to imply additional dimensions of time another way. That is the first Lorentz transformation error;the second is assumption of non-existent symmetry. 展开更多
关键词 WAVE-FUNCTION RELATIVITY doppler MASS De BROGLIE SCHRODINGER Matter-Waves Space-Time
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A Fourier Series Proof That the Axial like the Transverse Optical Doppler Shift Impacts Time and Information Rates
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作者 Samuel Reich 《Journal of High Energy Physics, Gravitation and Cosmology》 2019年第4期992-994,共3页
In writings on relativity time, the various relations are only changed by the transverse shift. This paper proves that the axial Doppler shift does that as well and gives some impacts of that on common differential re... In writings on relativity time, the various relations are only changed by the transverse shift. This paper proves that the axial Doppler shift does that as well and gives some impacts of that on common differential relations in physics. When a modulated signal lasting a time = T is subjected to an optical Doppler shift K (either axial or transverse or both), where K is shifted frequency/original frequency, the Doppler shifted signal will last T/K. This because all shifted harmonics of its Fourier series (with a fundamental period of T) will last 1/K times the period of the original harmonic. The reader can graph any Fourier series and then graph its shifted series. The reader will see the shifted period is T/K. The Fourier series of the original repeats when time is greater than T and the shifted one when time is greater than T/K, which means the original series only represents the signal from time = 0 to T and the shifted series represents the shifted signal from time = 0 to T/K. Hence, the shifted one has all of the information in T/K as the original has in T. Therefore everything in the series including information is T/K long in the shifted series. Therefore, both the axial and the transverse Doppler shift change time periods in a vacuum, independent of material involved. That has not been obvious for over 100 years the axial shift changes time from the definition of frequency = 1/time. 展开更多
关键词 Space TIME RELATIVITY doppler TIME INFORMATION Rates INFORMATION Transfer MISSING Dimensions
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A new model for Doppler shift of C-band echoes backscattered from sea surface
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作者 Jianbo Cui Yunhua Wang +4 位作者 Yanmin Zhang Huimin Li Wenzheng Jiang Yushi Zhang Xin Li 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第6期100-111,共12页
Within the framework of the two-scale scattering model,the Doppler shift of C-band radar return signals from the nonlinear sea surface are numerically evaluated.As an analytical approximation method,the Bragg resonanc... Within the framework of the two-scale scattering model,the Doppler shift of C-band radar return signals from the nonlinear sea surface are numerically evaluated.As an analytical approximation method,the Bragg resonance scattering method cannot accurately describe the backscattering field from sea surface.Therefore,in the twoscale scattering model,more accurate scattering coefficient(the normalized radar cross section,NRCS)evaluated by the C-band dual-polarized(HH/VV)empirical geophysical model function(CSAR model)is employed to replace the traditional Bragg NRCS to weight the Doppler shift.The numerical results indicate that there are obvious differences between the Doppler shift weighted by the CSAR NRCS and that weighted by the traditional Bragg NRCS.The hydrodynamic modulation of the large-scale waves is one of the important factors that affect the difference between the Doppler shift predicted in upwind and downwind directions.If the relaxation rate in the hydrodynamic modulation is set to be the angular frequency of the dominant water waves,the Doppler shift predicted by the numerical method can fit the results of the empirical model(C-band empirical geophysical model function,CDOP)well at moderate wind speed.Under low wind condition,the comparison shows that the empirical CDOP model appears to overestimate the Doppler shift.In order to facilitate the application,at the end of this paper a semi-empirical CSAR-DOP model,which is a polynomial fitting formula,is developed for evaluating the Doppler shift of C-band signals from time varying sea surface. 展开更多
关键词 doppler shift microwave scattering numerical simulation
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Effect Due to the Particle Nature of the Doppler Shifted Radiation on the Dynamics of the Spherical Light Emitting Source
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作者 Sameer Yadav 《Journal of High Energy Physics, Gravitation and Cosmology》 2023年第3期693-698,共6页
The Doppler effect is a phenomenon of intrinsic kinematic character. This paper analyzes the kinematic Doppler effect for the case where the source is moving and the observer is at rest in the classical limit. The par... The Doppler effect is a phenomenon of intrinsic kinematic character. This paper analyzes the kinematic Doppler effect for the case where the source is moving and the observer is at rest in the classical limit. The particle nature properties of radiation are considered and how it affects the dynamics of the Source has been studied. The dynamical and kinematical equations have been derived by considering this effect. It has been conclusively shown that a moving light-emitting source experiences a finite recoil momentum in the direction opposite to the direction of motion and come to rest in finite time. 展开更多
关键词 doppler Effect Light Emission Frequency shift Recoil Momentum
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Comparative Study of Radiological Changes in Hands and Feet in Patients Suffering from Early Rheumatoid Arthritis by Power Doppler Ultrasound and Direct Digital Radiography
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作者 Gargy Mondal Biswadip Ghosh +1 位作者 Manoranjan Ghosh Pampa Halder 《Open Journal of Rheumatology and Autoimmune Diseases》 2014年第1期39-42,共4页
Rheumatoid arthritis is a chronic multisystem disease of unknown cause. The characteristic feature of RA is persistent inflammatory synovitis. The natural history of disease is such that the early months of the diseas... Rheumatoid arthritis is a chronic multisystem disease of unknown cause. The characteristic feature of RA is persistent inflammatory synovitis. The natural history of disease is such that the early months of the disease are critical period during which reversible joint damage occurs. So early diagnosis of RA and appropriate drug application is the only way to save a patient from this crippling disease. In India, the cost of investigations is a significant factor for most of the patients. Ultrasonography or Power Doppler Ultra Sound (PDUS) has the advantage of being economic in spite of its sensitivity in assessing both inflammatory and destructive changes. The aim of the present study was to evaluate the diagnostic efficiency of PDUS in early rheumatoid arthritis. The study was performed with the patients attending Rheumatology Clinic. A total number of 106 patients of clinically suspected rheumatoid arthritis were studied as per selection criteria. Radiological examinations of hands were done by digital radiography and PDUS in a group of 53 patients, assessment of foot changes by PDUS and Digital Radiography were done in another similar group of 53 patients. Final diagnosis by ACR EULAR-2010 criteria is done for all the patients. The comparative study reveals that synovial vascularity as demonstrated by PDUS is much more effective in diagnosing early rheumatoid arthritis, both in hand and in feet than digital radiograph. PDUS of feet may yield earlier and better findings than hands, which is conventionally used in patients suffering from early rheumatoid arthritis. 展开更多
关键词 R.A.Rheumatoid Arthritis PDUSPower doppler Ultrasound D.R.Digital Radiography ACR-EULARAmerican College of RHEUMATOLOGY (ACR) and the European LEAGUE against RHEUMATISM (EULAR) RFRheumatoid Factor CRPc-Reactive Protein MRIMagnetic Resonance Imaging
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A Single Doppler Shift of Laser Doppler for Measured Average Velocity
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作者 Adnan Salih Ali shukur Mahmood Mariam Mohammed Abud 《材料科学与工程(中英文B版)》 2013年第4期256-261,共6页
关键词
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High-Precision Doppler Frequency Estimation Based Positioning Using OTFS Modulations by Red and Blue Frequency Shift Discriminator 被引量:1
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作者 Shaojing Wang Xiaomei Tang +3 位作者 Jing Lei Chunjiang Ma Chao Wen Guangfu Sun 《China Communications》 SCIE CSCD 2024年第2期17-31,共15页
Orthogonal Time Frequency and Space(OTFS) modulation is expected to provide high-speed and ultra-reliable communications for emerging mobile applications, including low-orbit satellite communications. Using the Dopple... Orthogonal Time Frequency and Space(OTFS) modulation is expected to provide high-speed and ultra-reliable communications for emerging mobile applications, including low-orbit satellite communications. Using the Doppler frequency for positioning is a promising research direction on communication and navigation integration. To tackle the high Doppler frequency and low signal-to-noise ratio(SNR) in satellite communication, this paper proposes a Red and Blue Frequency Shift Discriminator(RBFSD) based on the pseudo-noise(PN) sequence.The paper derives that the cross-correlation function on the Doppler domain exhibits the characteristic of a Sinc function. Therefore, it applies modulation onto the Delay-Doppler domain using PN sequence and adjusts Doppler frequency estimation by red-shifting or blue-shifting. Simulation results show that the performance of Doppler frequency estimation is close to the Cramér-Rao Lower Bound when the SNR is greater than -15dB. The proposed algorithm is about 1/D times less complex than the existing PN pilot sequence algorithm, where D is the resolution of the fractional Doppler. 展开更多
关键词 channel estimation communication and navigation integration Orthogonal Time Frequency and Space pseudo-noise sequence red-blue frequency shift discriminator
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An Orbit Determination Using SGP4 Propagator and Doppler Shifts for CubeSats 被引量:2
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作者 Wesam M.Elmahy Zhang Xiang +1 位作者 Lu Zhengliang Liao Wenhe 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2018年第3期472-482,共11页
The two line elements(TLEs),released by the North American Aerospace Defense Command(NORAD),are chosen for CubeSats' mission operators.Unfortunately,they have errors and other accompanied problems,which cause larg... The two line elements(TLEs),released by the North American Aerospace Defense Command(NORAD),are chosen for CubeSats' mission operators.Unfortunately,they have errors and other accompanied problems,which cause large deviations in the in-track component.When a TLE value is available at a certain epoch,the dominant error is the angular error.It is proposed to correct the angular error by solving-for the mean argument of latitude at the desired epoch.A batch least squares technique and range rate measurements are used for the correction process.With the assistance of satellite tool kit(STK)software and Matlab,a simulation to verify the orbit determination(OD)technique is implemented.This paper provides an angular correction low cost OD method and presents a complete analysis for various test cases.This approach maintains high accuracy in cross-track and radial and makes great improvement in in-track at the same time,but it is exclusive for circular orbits.When it is applied to an elliptical orbit,the error will be unacceptable.Therefore,the angular error is corrected using the longitude of periapsis which totally mitigates the error at the epoch under consideration.For inclinations less than 20 o,the mean longitude is preferred for the angular correction as it provides more accuracy compared with the mean argument of latitude. 展开更多
关键词 CUBESAT low earth orbit(LEO) orbit determination doppler shift two line elements(TLEs)
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Transcranial Doppler ultrasonography: From methodology to major clinical applications 被引量:10
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作者 Antonello D'Andrea Marianna Conte +11 位作者 Massimo Cavallaro Raffaella Scarafile Lucia Riegler Rosangela Cocchia Enrica Pezzullo Andreina Carbone Francesco Natale Giuseppe Santoro Pio Caso Maria Giovanna Russo Eduardo Bossone Raffaele Calabrò 《World Journal of Cardiology》 CAS 2016年第7期383-400,共18页
Non-invasive Doppler ultrasonographic study of cerebral arteries [transcranial Doppler(TCD)] has been extensively applied on both outpatient and inpatient settings. It is performed placing a low-frequency(≤ 2 MHz) tr... Non-invasive Doppler ultrasonographic study of cerebral arteries [transcranial Doppler(TCD)] has been extensively applied on both outpatient and inpatient settings. It is performed placing a low-frequency(≤ 2 MHz) transducer on the scalp of the patient over specific acoustic windows, in order to visualize the intracranial arterial vessels and to evaluate the cerebral blood flow velocity and its alteration in many different conditions. Nowadays the most widespread indication for TCD in outpatient setting is the research of right to left shunting, responsable of so called "paradoxical embolism", most often due to patency of foramen ovale which is responsable of the majority of cryptogenic strokes occuring in patients younger than 55 years old. TCD also allows to classify the grade of severity of such shunts using the so called "microembolic signal grading score". In addition TCD has found many useful applications in neurocritical care practice. It is useful on both adults and children for day-to-day bedside assessment of critical conditions including vasospasm in subarachnoidal haemorrhage(caused by aneurysm rupture or traumatic injury), traumatic brain injury, brain stem death. It is used also to evaluate cerebral hemodynamic changes after stroke. It also allows to investigate cerebral pressure autoregulation and for the clinical evaluation of cerebral autoregulatory reserve. 展开更多
关键词 Transcranial doppler ultrasonography Lindegaard ratio PARADOXICAL EMBOLISM Microembolic signals Middle cerebral artery Patent foramen ovale CRYPTOGENIC STROKE VASOSPASM Acute SUBARACHNOID hemorrhage Ischemic STROKE
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Model of Universe as Described by Dynamic Universe Model
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作者 Satyavarapu Naga Parameswara Gupta 《Open Journal of Modelling and Simulation》 2019年第1期41-78,共38页
In this paper we will see the model of Universe according to Dynamic Universe Model of Cosmology by visualizing various processes that are happening in the Universe as per experimental evidences. For simplifying the m... In this paper we will see the model of Universe according to Dynamic Universe Model of Cosmology by visualizing various processes that are happening in the Universe as per experimental evidences. For simplifying the matter here, we will see in part 1: about the Galaxy life cycle, where the birth and death of Galaxies discussed. Probably Universe gives guidance for the movement of Galaxies. We call this Part 1: Thinking and Reproducing Universe or Mindless Universe? (Galaxy life cycle). We see every day Sun, Stars, Galaxies etc., dissipating enormous energy in the form of radiation by the way of fusion of Hydrogen to helium. So after sometime all the Hydrogen is spent and Universe will die, is it not? … Dynamic Universe Model says that the energy in the form of electromagnetic radiation passing grazingly near any gravitating mass changes in frequency and finally will convert into neutrinos (mass). Hence Dynamic Universe Model proposes another process where energy will be converted back into matter and the cycle energy to mass to energy continues, sustaining the Universe to maintain this present status for ever in this form something like a Steady state model without any expansion. This we will see in Part 2: Energy - Mass - Energy Cycle. After converting energy into mass “how various elements are formed and where they are formed?” will be next logical question. Dynamic Universe Model says that these various particles change into higher massive particles or may get bombarded into stars or planets and various elements are formed. Here we bifurcate the formation of elements into 6 processes. They are for Elementary particles and elements generated in frequency changing process, By Cosmic rays, By Small stars, By Large Stars, By Super Novae and Manmade elements By Neutron Stars. This we will discuss in Part 3: Nucleosynthesis. 展开更多
关键词 DYNAMIC UNIVERSE MODEL Hubble Space Telescope (HST) SITA Simulations (SITA-Simulation of Inter Intra Tautness Attraction Forces Used by DYNAMIC UNIVERSE Model) Singularity-Free COSMOLOGY Blue shifted GALAXIES Red shifted GALAXIES Grazing Radiation Frequency Changes Formation of Elements Nucleosynthesis DYNAMIC UNIVERSE MODEL Energy to Mass Conversion Methods: N-Body Simulations-Gravitation-Cosmology
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Joint Doppler Shift and Channel Estimation for UAV mmWave System with Massive ULA 被引量:5
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作者 Yanan Li Yue Zhu +1 位作者 Tiankui Zhang Dian Fan 《China Communications》 SCIE CSCD 2022年第4期67-82,共16页
A joint Doppler shift and channel estimation method for the millimeter-wave communication system of an unmanned aerial vehicle(UAV) equipped with a large-scale uniform linear antenna(ULA) array has been proposed. Sinc... A joint Doppler shift and channel estimation method for the millimeter-wave communication system of an unmanned aerial vehicle(UAV) equipped with a large-scale uniform linear antenna(ULA) array has been proposed. Since Doppler shift induces intercarrier interference, the parameters of the channel paths have been decomposed into the Doppler shift and the channel information. In order to obtain the Doppler shift, a new estimation algorithm based on a combination of discrete Fourier transform and phase rotation has been proposed, which can determine the appropriate number of antennas. In addition to estimating the channel information, a low-complexity joint Doppler shift and channel estimation method has been designed that can quickly obtain accurate estimates. Furthermore, the achievable sum rate, the theoretical bounds of the mean squared errors, and the Cram?er-Rao lower bounds of the estimation method have been derived. The analysis and simulation results prove that the performance of the proposed approach is close to the theoretical inference. 展开更多
关键词 ULA doppler shift estimation channel estimation achievable sum rate
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Analysis of Commuting Modal Shift in Consideration of Social Interaction of Consciousness for Environment
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作者 Masashi Okushima 《Journal of Traffic and Transportation Engineering》 2024年第2期63-80,共18页
It is the matter for achievement of the low carbon transport system that the excessive use of private vehicles can be controlled appropriately.Not only improvement of service level of modes except private vehicle,but ... It is the matter for achievement of the low carbon transport system that the excessive use of private vehicles can be controlled appropriately.Not only improvement of service level of modes except private vehicle,but also consciousness for environmental problem of individual trip maker is important for eco-commuting promotion.On the other hand,consciousness for environment would be changed by influence of other person.Accordingly,it is aimed in the study that the structure of decision-making process for modal shift to the eco-commuting mode in the local city is described considering environmental consciousness and social interaction.For the purpose,the consciousness for the environment problem and the travel behavior of the commuter at the suburban area in the local city are investigated by the questionnaire survey.The covariance structure about the eco-consciousness is analyzed with the database of the questionnaire survey by structural equation modeling.As the result,it can be confirmed with the structural equation model that the individual environmental consciousness is strongly related with the intention of self-sacrifice and is influenced with the local interaction of the individual connections.On the other hand,the intention of modal shift for the commuting mode is analyzed with the database of the questionnaire survey.It can be found out that the environmental consciousness is not statistically significant for commuting mode choice with the present poor level of service of public transport.However,the intention of self-sacrifice for the prevention of the global warming is statistically confirmed as the factor of modal shift with the operation of eco-commuting bus service with the RP/SP integrated estimation method.As the result,the multi-agent simulation system with social interaction model for eco consciousness is developed to measure the effect of the eco-commuting promotion.For the purpose,the carbon dioxide emission is estimated based on traffic demand and road network condition in the traffic environment model.On the other hand,the relation between agents is defined based on the small world network.The proposed multi-agent simulation is applied to measure the effect of the eco-commuting promotion such as improvement of level of service on the public transport or education of eco-consciousness.The effect of the promotion plan can be observed with the proposed multi-agent system.Finally,it can be concluded that the proposed multi-agent simulation with social interaction for eco-consciousness is useful for planning of eco-commuting promotion. 展开更多
关键词 Greenhouse gas emission modal shift structural equation model RP/SP combined estimation multi-agent simulation local interaction small world network consciousness for environment commuting shuttle bus local city
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Two Strong Simple Proofs That All Doppler Shifts (including the Axial) Impact Observed Time, and All the Transverse Does
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作者 Samuel Lewis Reich 《Journal of High Energy Physics, Gravitation and Cosmology》 2020年第4期765-773,共9页
The first proof (Sections 2 - 4), applies Doppler shifts to the Fourier time sine series. It shows if <i>K</i> = <i>f'/f</i> (frequency ratio of the shift, <i>f'</i> the shi... The first proof (Sections 2 - 4), applies Doppler shifts to the Fourier time sine series. It shows if <i>K</i> = <i>f'/f</i> (frequency ratio of the shift, <i>f'</i> the shifted frequency), then the value of the series at time = t occurs in the shifted series at time = <i>t/K</i>. That is because in each harmonic the sin(<i>f't</i>) and cos(<i>f't</i>) became sin(<i>Kft</i>) and cos(<i>Kft</i>). The original series could be the number of photons in area of a beam with encoded information. Therefore the number of observed photons and information has the same resultant Doppler shift as frequency. Resultant is total effect of axial, transverse and gravitational shifts. Mass and energy of light do not have the same Doppler shift which may indicate missing parts that Doppler shift and that mass traveling at the speed of light is different from other mass and energy. The second proof (Section 5) the vector equations of space time require observed time to have 3 dimensions if the speed of light is constant in all directions, but the Doppler shift in each direction is not the same. The blue shift (compression) of time has paradoxes. If time has many dimensions, that would solve the paradoxes, but break conservation laws. No solution of that is given here. It is not expected that radical a solution will have any followers. 展开更多
关键词 doppler RELATIVITY Aether Fourier Series Time Travel Paradox INVARIANTS
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Doppler shift of a laser pulse beam scattered by a rotating cone and cylinder
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作者 王保平 王明军 +2 位作者 吴振森 李应乐 向宁静 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第5期60-65,共6页
Based on laser radar equations, a Doppler shift model of a laser pulse beam scattered by a rotating arbitrary convex target is reported in this paper. The boundary relations between an incident pulse beam and the dete... Based on laser radar equations, a Doppler shift model of a laser pulse beam scattered by a rotating arbitrary convex target is reported in this paper. The boundary relations between an incident pulse beam and the detected area elements are analyzed by geometric methods. The Doppler shift characteristics of the rotating cone and cylinder are discussed and the difference between the laser pulse beam and the plane wave scattered from the same rotating target is compared accordingly. Numerical simulations show that the Doppler shift is tightly relevant to their dimensions, speeds, and so on. In the same incidence conditions, the pulse beam and plane wave have difference peak values and the same Doppler shift bandwidth. If the waist radius of the pulse beam is larger, the peak value is higher, and the Doppler shifts are proportional to the speed of the rotating target. By virtue of our theoretical model, we probe into the scattered characteristics of the Doppler shifts of a laser pulse beam, which would benefit target identification in national defense. 展开更多
关键词 scattered characteristics of laser pulse beams doppler shift laser radar target identification
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Investigation on the Doppler shifts induced by 1-D ocean surface wave displacements by the first order small slope approximation theory:comparison of hydrodynamic models
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作者 王运华 张彦敏 郭立新 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第7期230-237,共8页
Based on the first order small slope approximation theory (SSA-I) for oceanic surface electromagnetic scattering, this paper predicts the Doppler shifts induced by wave displacements. Theoretical results from three ... Based on the first order small slope approximation theory (SSA-I) for oceanic surface electromagnetic scattering, this paper predicts the Doppler shifts induced by wave displacements. Theoretical results from three distinct hydrody- namic models are compared: a linear model, the nonlinear Barrick model, and the nonlinear Creamer model. Meanwhile, the predicted Doppler shifts are also compared with the results associated to the resonant Bragg waves and the so-called long waves in the framework of the two-scale model. The dependences of the predicted Doppler shifts on the incident angle, the radar frequency, and the wind speed are discussed. At large incident angles, the predicted Doppler shifts for the linear and nonlinear Barrick models are found to be insensitive to the wind speed and this phenomenon is not coincident with the experimental data. The conclusions obtained in this paper are promising for better understanding the properties of time dependent radar echoes from oceanic surfaces. 展开更多
关键词 doppler shifts sea surface model SSA-I electromagnetic scattering
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Doppler shift based stable clustering scheme for mobile ad hoc networks
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作者 Ni Minming Zhong Zhangdui +1 位作者 Chen Ruifeng Zhao Dongmei 《High Technology Letters》 EI CAS 2011年第4期414-420,共7页
This paper addresses the clustering problem for mobile ad hoc networks. In the proposed scheme, Doppler shift associated with received signals is used to estimate the relative speed between aelnster head and its membe... This paper addresses the clustering problem for mobile ad hoc networks. In the proposed scheme, Doppler shift associated with received signals is used to estimate the relative speed between aelnster head and its members. With the estimated speed, a node can predict its stay time in every nearby cluster. In the initial clustering stage, a node joins a duster that can provide it with the longest stay time in order to reduce the number of re-affiliations. In the cluster maintaining stage, strategies are designed to help node cope with connection break caused by channel fading and node mobility. Simulation results show that the proposed clustering scheme can reduce the number of re-affiliations and the average disconnection time compared with previous schemes. 展开更多
关键词 mobile ad hoc network CLUSTERING doppler shift relative speed estimation
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Measurement and analysis of Doppler shift for high-speed rail scenario
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作者 丁建文 Jiang Wenyi +2 位作者 Zhong Zhangdui Guan Ke Ai Bo 《High Technology Letters》 EI CAS 2015年第2期192-199,共8页
Based on the analysis of the impact of Doppler shift to the railway dedicated mobile communication quality under the condition of high-speed mobility,this paper presents a Doppler shift measurement approach based on t... Based on the analysis of the impact of Doppler shift to the railway dedicated mobile communication quality under the condition of high-speed mobility,this paper presents a Doppler shift measurement approach based on the phase estimation of frequency correction channel(FCCH) which correctly reflects the time-varying characteristic of the channel with a testing system developed.The Doppler shift data under the high-speed condition is collected,processed,analyzed,and compared with the simulation results.The scientific laws of the Doppler shift distribution of radio channel under high-speed condition are obtained.These data and analysis are essential for the establishment of high-speed railway Doppler power spectrum model and the development of the key technology of antiDoppler shift. 展开更多
关键词 doppler shift high-speed railway HSR phase estimation software radio
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光学薄膜中界面层和表面吸附层对相位延迟的影响 被引量:2
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作者 黄建兵 邵建达 范正修 《红外与毫米波学报》 SCIE EI CAS CSCD 北大核心 2005年第2期105-108,共4页
多层介质反射镜在非正入射的时候,两个不同的偏振态之间会产生不同的相移.根据空气与膜层、膜层之间的实际情况,建立了界面层和表面吸附层模型,并运用它分析相位延迟产生误差的原因.通过优化设计,入射角为54°,在1285~1345nm之间p,... 多层介质反射镜在非正入射的时候,两个不同的偏振态之间会产生不同的相移.根据空气与膜层、膜层之间的实际情况,建立了界面层和表面吸附层模型,并运用它分析相位延迟产生误差的原因.通过优化设计,入射角为54°,在1285~1345nm之间p,s波获得了270±1°的相移,同时也使反射率在99.5%以上.用离子束溅射技术制备相位延迟膜,用分光光度计测试了光谱特性和用椭偏仪测试了相位特性,在相应波段获得了262.4±1.8°的相移,同时也使反射率在99.6%以上.误差的主要来源是离子源工作特性会产生不均匀的过渡层和最外层会吸收一些水汽、灰尘等也产生表面过渡层.由误差分析得出了制备中过渡层的物理厚度和折射率的变化情况,最外层的厚度误差和折射率偏差是发生相移偏小的主要因素. 展开更多
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The New Doppler Shift-and-Range Positioning Algorithm for the Global Navigation Satellite System 被引量:2
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作者 季海福 《天文研究与技术》 CSCD 2014年第1期13-18,共6页
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