Doppler Effect: A Look from Biology Aging

The Doppler effect can be defined as the frequency shift suffered by a wave phenomenon, when there is a difference in relative speed between the waves generated and their source. We know that it occurs in the case of mechanical and electromagnetic waves. We propose to generalize the Doppler effect to the case of frequency changes of certain oscillatory variables in biology before and after puberty, starting from the basis that a metabolically accelerated system is equivalent to a mechanically accelerated system. We then established the following objectives: To verify if there is an average difference in heart and respiratory rates, before and after puberty. To verify the association of these frequency differences with the metabolic activity estimated as basal metabolic rate or BMR. We studied heart and respiratory rate data from healthy people of both sexes, verifying the frequency distribution before and after puberty. We also study the relationship of the frequency distribution with the evolution of the basal metabolic rate throughout life. Analysis of the results shows that the highest heart and respiratory rates occur before puberty, while the lowest rates occur after puberty. A high correlation of the evolution of the variables studied with the evolution of the metabolic acceleration of the system throughout life is also evident. Taking into account that a mechanically accelerated system is equivalent to a metabolically accelerated system, we can conclude that the frequency distribution found is the expression of a generalization of the Doppler effect in the case of biological physical systems.

Correlation method estimation of the modulation signal in the weak equivalence principle test

In a test of the weak equivalence principle （WEP） with a rotating torsion pendulum, it is important to estimate the amplitude of the modulation signal with high precision. We use a torsional filter to remove the free oscillation signal and employ the correlation method to estimate the amplitude of the modulation signal. The data analysis of an experiment shows that the uncertainties of amplitude components of the modulation signal obtained by the correlation method are in agreement with those due to white noise. The power spectral density of the modulation signal obtained by the correlation method is about one order higher than the thermal noise limit. It indicates that the correlation method is an effective way to estimate the amplitude of the modulation signal and it is instructive to conduct a high-accuracy WEP test.

Systematic error suppression scheme of the weak equivalence principle test by dual atom interferometers in space based on spectral correlation

Systematic error suppression and test data processing are very important in improving the accuracy and sensitivity of the atom interferometer(AI)-based weak-equivalence-principle(WEP) test in space. Here we present a spectrum correlation method to investigate the test data of the AI-based WEP test in space by analyzing the characteristics of systematic errors and noises. The power spectrum of the Eotvos coefficient η, systematic errors, and noises in AI-based WEP test in space are analyzed and calculated in detail. By using the method, the WEP violation signal is modulated from direct current(DC) frequency band to alternating current(AC) frequency band. We find that the signal can be effectively extracted and the influence of systematic errors can be greatly suppressed by analyzing the power spectrum of the test data when the spacecraft is in an inertial pointing mode. Furthermore, the relation between the Eotvos coefficient η and the number of measurements is obtained under certain simulated parameters. This method will be useful for both isotopic and nonisotopic AI-based WEP tests in space.

Effect of gravity gradient in weak equivalence principle test

A high accuracy test of the weak equivalence principle（WEP） is of great scientific significance no matter whether its result is positive. We analyze the gravity gradient effect which is a main systematic error source in the test of WEP.The result shows that the uncompensated gravity gradient effect from the coupling term of the dominated gravity gradient multipole moment component q_（21） and the relative multipole field component Q_（21） contributes to an uncertainty of 1×10^（-11） on the E otv os parameter. We make a Q_（21） compensation to reduce the effect by about 20 times, and the limit of the test precision due to this coupling is improved to a level of a part in 10^（13）.

Suppression of Coriolis error in weak equivalence principle test using ^85Rb-^87Rb dual-species atom interferometer

Coriolis effect is an important error source in the weak equivalence principle(WEP)test using atom interferometer.In this paper,the problem of Coriolis error in WEP test is studied theoretically and experimentally.In theoretical simulation,the Coriolis effect is analyzed by establishing an error model.The measurement errors of Eotvos coefficient(η)in WEP test related to experimental parameters,such as horizontal-velocity difference and horizontal-position difference of atomic clouds,horizontal-position difference of detectors,and rotation compensation of Raman laser’s mirror are calculated.In experimental investigation,the position difference between^85Rb and^87Rb atomic clouds is reduced to 0.1 mm by optimizing the experimental parameters,an alternating detection method is used to suppress the error caused by detection position difference,thus the Coriolis error related to the atomic clouds and detectors is reduced to 1.1 × 10^-9.This Coriolis error is further corrected by com pensating the rotation of Raman laser's mirror,and the total uncertainty o f rj measurement related to the Coriolis effect is reduced as δη=4.4 × 10^-11.

Design and Evaluation of a Differential Accelerometer for Drop-Tower Equivalence Principle Test with Rotating Masses

A differential accelerometer comprising of two rotating masses made of the same material is proposed for drop tower-based free-fall testing of the spin-spin force between the rotating mass and the Earth. The measurement is performed by placing the two concentric masses of very different momenta in a vacuum drop capsule which is falling freely in the Earth＇s gravitational field. A nonzero output of the differential aeeelerometer is an indication of possible violation of new equivalence principle （NEP）. We present the conceptual design of a modified free-fall NEP experiment which can be performed at the Belting drop tower. Design and evaluation of the differential accelerometer with a hybrid electrostatic/magnetic suspension system are presented to accommodate for operation on ground and drop-tower tests. Details specific to the measurement uncertainty are discussed to yield an NEP test accuracy of 7.2×10^-9.

Determination of the thermal noise limit in test of weak equivalence principle with a rotating torsion pendulum

Thermal noise is one of the most fundamental limits to the sensitivity in weak equivalence principle test with a rotating torsion pendulum. Velocity damping and internal damping are two of many contributions at the thermal noise, and which one mainly limits the torsion pendulum in low frequency is difficult to be verified by experiment. Based on the conventional method of fast Fourier transform, we propose a developed method to determine the thermal noise limit and then obtain the precise power spectrum density of the pendulum motion signal. The experiment result verifies that the thermal noise is mainly contributed by the internal damping in the fiber in the low frequency torsion pendulum experiment with a high vacuum. Quantitative data analysis shows that the basic noise level in the experiment is about one to two times of the theoretical value of internal damping thermal noise.

Effect of aperture field distribution on the maximum radiated power at atmospheric pressure

The air breakdown in the high-power antenna near-field region limits the enhancement of the radiated power. A model coupling the field equivalent principle and the electron number density equation is presented to study the breakdown process in the near-field region of the circular aperture antenna at atmospheric pressure. Simulation results show that, although the electric field in the near-field region is nonuniform, the electron diffusion has small influence on the breakdown process when the initial electron number density is uniform in space. The field magnitude distribution on the aperture plays an important role in the maximum radiated power above which the air breakdown occurs. The maximum radiated power also depends on the phase difference of the fields at the center and edge of the aperture, especially for the uniform field magnitude distribution.

TIME-TEMPERATURE-STRESS EQUIVALENCE AND ITS APPLICATION TO NONLINEAR VISCOELASTIC MATERIALS

Stress-dependence of the intrinsic time of viscoelastic materialsis investigated. The influence of stress level on the intrinsic timeis considered to be similar to that of temperature, pressure, solventcon- centration, damage and physical aging. Thetime-temperature-stress equivalence principle is proposed, byemploying which, the creep curves at different temperatures andstress level can be shifted into a master curve at referencetemperature and stress level.

Remarks on interpretations of the Eotvos experiment and misinterpretation of E=mc^2

The Eotvos experiment on the verification of equivalence between inertial mass and gravitational mass of a body is famous for its accuracy. A question is, however, can these experimental results be applied to the case of a physical space in general relativity, where the space coordinates could be arbitrary？ It is pointed out that it can be validly applied because it has been proven that Einstein＇s equivalence principle for a physical space must have a frame of reference with the Euclidean-like structure. Will claimed further that such an overall accuracy can be translated into an accuracy of the equivalence between inertial mass and each type of energy. It is shown that, according to general relativity, such a claim is incorrect. The root of this problem is due to an inadequate understanding of special relativity that produced the famous equation E=mc^2, which must be understood in terms of energy conservation. Concurrently, it is pointed out that this error is a problem in Will＇s book, ‘Theory and Experiment in Gravitational Physics＇.

Encoding Energy-Density as Geometry

Physicists possess an intuitive awareness of Euclidian space and time and Galilean transformation, and are then challenged with Minkowski space-time and Einstein’s curved space-time. Relativistic experiments support the “time-dilation” interpretation and others support “curved space-time” interpretation. In this, and related work, we investigate the key issues in terms of the intuitive space-time frame. In particular, we provide alternative approaches to explain “time dilation” and to explain the energy density for gravity systems. We approach the latter problem from an information perspective.

A New Fracability Evaluation Approach for Shale Reservoirs Based on Multivariate Analysis: A Case Study in Zhaotong Shale Gas Demonstration Zone in Sichuan, China

Fracability characterizes the effectiveness of hydraulic fracturing.The existing assessment methods cannot reflect the actual value of the effectiveness due to a lack of comprehensive consideration and neglect of the influences of engineering factors.This study aims to solve this problem by implementing geological static data and production dynamic data in multivariate analysis in Zhaotong shale gas demonstration zone.First,the reservoir quality index(RQI)was introduced to evaluate the exploration potential by integrating the geological parameters with gray relational analysis.Moreover,the differences in fracturing fluid types and proppant sizes were considered,and the operating parameters were normalized on the basis of the equivalence principle.Finally,the general reservoir fracability index(GRFI)was proposed based on a dimensioned processing of the various parameters.A case study was conducted to verify the accuracy and feasibility of this new approach.The results demonstrate that(1)the organic carbon and gas content are adjusted to contribute the most to the calculation of the RQI,while the effective porosity contributes the least;(2)the fracturing scale is the main operating parameter determining the fracability,which has the strongest correlation with the effectiveness of fracking;and(3)the GRFI has a positive correlation with shale gas production,and the lower limit of the GRFI of 2,000 corresponds to a daily production of 50,000 m3/d;this value is defined as the threshold value of a stripper well.The GRFI is consistent with the productivity trend of shale gas wells in the research block,which suggests that the new model is accurate and practical for well candidate selection.

Common-mode noise rejection using fringe-locking method in WEP test by simultaneous dual-species atom interferometers

We theoretically investigate the application of the fringe-locking method（FLM） in the dual-species quantum test of the weak equivalence principle（WEP）.With the FLM,the measurement is performed invariably at the midfringe,and the extraction of the phase shift for atom interferometers is linearized.For the simultaneous interferometers,this linearization enables a good common-mode rejection of vibration noise,which is usually the main limit for high precision WEP tests of the dual-species kind.We note that this method also allows for an unbiased determination of the gravity accelerations difference,which meanwhile is ready to be implemented.

EM Scattering from Conducting Flat Plates Coated with Thin RAM

According to the equivalence principles, high frequency approximation and boundary conditions, a method has been developed to deal with the EM scattering by a rectangular conducting flat plate coated with uniaxial anisotropic radar absorbing material (RAM). The simple and effective method is available to the system of RCS prediction in which the large complex targets modeled by facets and wedges. Numerical results show some properties of EM scattering by conducting plate coated with thin uniaxial anisotropic RAM.

Gravitational Time Dilation inside the Solid Sphere

Gravitational time dilation directly reflects the difference between gravitational potentials at different altitudes in the gravitational field. At the same time this phenomenon is expected to obey the Einstein’s equivalence principle, one of two pillars (apart from general covariance) of general relativity. The experiments aimed at detecting the gravitational time dilation are therefore described as the tests of general relativity or, alternatively, the tests of equivalence principle. When applied to the exterior of a solid sphere, these two interpretations are fully compatible both theoretically and experimentally. However, when applied to the interior of a solid sphere (e.g., to the interior of Earth), they seem to contradict each other. Namely, a strict dependence of the gravitational time dilation on the gravitational potential inside the sphere proves to be at odds with the equivalence principle. This paper reveals this problem and provides solution to it. As a consequence, it is concluded that, contrary to the current belief, the Earth’s center is older, not younger, than the Earth’s surface. Since all the previous experiments have been performed either on or above the Earth’s surface, an experiment performed below the Earth’s surface is proposed.

A Conceptual Deficiency for the Use of Christoffel Connection in Gravity Theories

Christoffel connection (or Levi-Civita affine connection) did not enter gravity as an axiom of minimal length for the free fall of particles (where anyway length action is not defined for massless particles), nor out of economy, but from the weak equivalence principle (gravitational force is equivalent to acceleration according to Einstein) together with the identification of the local inertial frame with the local Lorentz one. This identification implies that the orbits of all particles are given by the geodesics of the Christoffel connection. Here, we show that in the presence of only massless particles (absence of massive particles), the above identification is inconsistent and does not lead to any connection. The proof is based on the existence of projectively equivalent connections and the absence of proper time for null particles. If a connection derived by some kinematical principles for the particles is to be applied in the world, it is better for these principles to be valid in all relevant spacetime rather than different principles to give different connections in different spacetime regions. Therefore, our result stated above may imply a conceptual insufficiency of the use of the Christoffel connection in the early universe where only massless particles are expected to be present (whenever at least some notions, like orbits, are meaningful), and thus of the total use of this connection. If in the early universe, the notion of a massive particle, which appears latter in time, cannot be used, in an analogous way in a causally disconnected high-energy region (maybe deep interior of astrophysical objects or black holes), the same conclusions could be extracted if only massless particles are present.

Discussion on Nida's Translation Theory and Applications Through MuLAN

Eugene Nida's Translation Theory has a profound influence both on global and Chinese translation circle.Although this theory is widely used,it also become a controversial topic in a certain extent.Through the movie MuLAN and some applications in useful areas to discuss whether Nida's Translation Theory is still applicable within translating field.

An improved equivalent beam model of large periodic beam-like space truss structures

Space truss structures are essential components for space-based remote sensing loads with high spatial and temporal resolutions.To achieve high-precision vibration control,an accurate and efficient dynamics model is essential.In addition to the current equivalent beam model(EBM)based on the classical continuum theory,an improved equivalent beam model(IEBM)is proposed that considers the impact of the distinction between trusses and beams on torsional and shear deformations,as well as the impact of shear deformation on flexural rigidity.According to the displacement expressions of spatial beams,torsional,shear,and bending correction coefficients are introduced to derive expressions of strain energy and kinetic energy.The energy equivalence principle is then utilized to calculate the elasticity and inertia matrices,and dynamics equations are established using the finite element method.Subsequently,an IEBM is constructed by employing the particle swarm optimization approach to determine the correction coefficients with the truss natural frequency as the optimization target.The natural vibration characteristics of the structure are estimated for various material properties.Compared with the full-scale finite element model,the EBM reaches a maximum error of 80%for a low modulus of elasticity,while the maximum error of the IEBM is less than 2%for any given parameters,indicating its superior accuracy to the EBM.

Determination of the Uniaxial Stress-Strain Relations of Ductile Materials by Small Disk Specimens

In this work,the small lateral-compression testing based on energy equivalent(SLTEE)method is put forward to determine the stress-strain curves of materials utilizing small disk specimens.Numerical simulations of small lateral-compression testing with imaginary materials are conducted to examine the validity of the SLT-EE method.The results demonstrate that the stress-strain curves determined by the SLT-EE method coincide with the curves input by finite element analysis.In order to predict the stress-strain curves of materials with different dimensions,a modified SLT-EE method is successfully proposed by introducing a correction factor/.Finally,the small disk compression experiments of Q345B,304,7075 and 6061 are performed.The stress-strain curves of the four materials predicted by the SLT-EE method show agreement with the tension results.Furthermore,the mechanical properties of in-service hollow components are also determined utilizing the same method successfully.

Compliance-based testing method for fatigue crack propagation rates of mixed-modeⅠ-Ⅱcracks

Mixed-mode I-II crack-based fatigue crack propagation(FCPⅠ-Ⅱ)usually occurs in engineering structures;however,no theoretical formula or effective compliance test methods have been established for FCPI-IIto date.For mixed-mode I-II flawed components,based on the principle of mean-value energy equivalence,we propose a theoretical method to describe the relationship between material elastic parameters,geometrical dimensions,load(or displacement),and energy.Based on the maximum circumferential stress criterion,we propose a uniform compliance model for compact tensile shear(CTS)specimens with horizontal cracks deflecting and propagating(flat-folding propagation)under different loading angles,geometries,and materials.Along with an innovative design of the fixture of CTS specimens used for FCPI-IItests,we develop a new compliancebased testing method for FCPⅠ-Ⅱ.For the 30Cr2Ni4MoV rotor steel,the FCP rates of modeⅠ,modeⅡ,and mixed-modeⅠ-Ⅱcracks were obtained via FCP tests using compact tension,Arcan,and CTS specimens,respectively.The obtained da/d N versusΔJ curves of the FCP rates are close.The loading angleαand dimensionless initial crack length a0/W demonstrated negligible effects on the FCP rates.Hence,the FCP rates of mode I crack can be used to predict the residual life of structural crack propagation.