Phase Difference Curves Research Articles

Ultrasonic Sensor: A Fast and Non-Destructive System to Measure the Viscosity and Density of Molecular Fluids.

This study presents the design and development of an ultrasonic sensor as a fundamental tool for characterizing the properties of fluids and biofluids. The analysis primarily focuses on measuring the electrical parameters of the system, which correlate with the density and viscosity of the solutions, in sample volumes of microliters and with high temporal resolution (up to 1 data point per second). The use of this sensor allows the fast and non-destructive evaluation of the viscosity and density of fluids deposited on its free surface. The measurements are based on obtaining the impedance versus frequency curve and the phase difference curve (between current and voltage) versus frequency. In this way, characteristic parameters of the transducer, such as the resonance frequency, phase, minimum impedance, and the quality factor of the resonant system, can characterize variations in density and viscosity in the fluid under study. The results obtained revealed the sensor's ability to identify two parameters sensitive to viscosity and two parameters sensitive to density. As a proof of concept, the unfolding of the bovine albumin protein was studied, resulting in a curve that reflects its unfolding kinetics in the presence of urea.

Reservoir water flooding evaluation based on electromagnetic wave logging permittivity and conductivity inversion

Electromagnetic wave logging at the measurement frequency of megahertz provides two kinds of information namely conductivity and permittivity, which is helpful to solve the problem of identifying water flooding situation of oil layers after long-term water displacement development. The electromagnetic wave combination logging tool in Daqing Oilfield measures two phase difference curves at frequencies of 60 MHz and 2 MHz. At present, there is still a lack of permittivity and conductivity inversion methods for this tool that are suitable for the interpretation of water flooding situation. Based on the magnetic dipole theory of uniform medium, the study found that for the combination logging tool, the 60 MHz phase difference is affected by both the permittivity and conductivity of the formation, while the 2 MHz phase difference is mainly affected by the conductivity. The reasonable and conveniently procedure for calculating the permittivity and conductivity from the inversion of the phase difference curves is constructed. Firstly, the shale content and porosity parameters of the layers are calculated from the curves of natural gamma and acoustic time difference, while the permittivity is calculated by a formula linearly constrained by shale content based on the permittivity of mudstone and oil-bearing clean sandstone. Secondly, for 2 MHz phase difference curve, a formula for calculating conductivity with known permittivity is established. Thirdly, set the calculated permittivity as the known parameter, a formula for inversion of the 2 MHz phase difference curve to calculate the conductivity is derived. Fourthly, using the inversion calculation of the conductivity as a known input, establish a formula for inversion of the 60 MHz phase difference curve to calculate the permittivity. In the process, the permittivity calculated by the shale content constraint method is used as the initial value of the iteration, which weakens the influence of mudstone on the permittivity and ensures the accuracy of the iteration. Finally, the permittivity and conductivity calculated by inverse calculation for two sealed coring wells can reflect the flooding situation of layers. The identification standard of flooding levels was established by using the conductivity and permittivity of inversion calculation, and the coincidence rate reached 90.7%, which is suitable for the effective identification of remaining oil in the long-term fresh water displacement layers. At the same time, based on the simplified theoretical model, the inversion of 3 combination of (2 MHz, 20 MHz), (60 MHz, 20 MHz), (2 MHz, 100 MHz) is carried out respectively, and the calculated values of remaining oil saturation are consistent with the injected water sweeping area, so the universality of the research method is verified.

Phase Measurement of Guided-Mode Resonance Device Using Digital Micromirror Device Gratings

This paper reports on the measurement system of the phase difference between s- and p-polarization components of the light passing through a guided-mode resonance (GMR) device using a digital micromirror device (DMD) gratings as a digital phase-shifting device. The phase of the non-zeroth order diffraction beams of the grating pattern displayed on the DMD can exhibit a phase change when the grating pattern is shifted. Two nearest different diffraction orders of p-polarized and s-polarized beams can be used as the reference and measurement beams, respectively, and are combined to implement the phase-shifting interferometry (PSI). The phase difference between the s- and the p-polarization components of the incident light passing through the GMR device can be obtained by applying the four-step phase-shift algorithm to the DMD-based PSI system. Experimental results show that this measurement system has a phase detection limit of 1° and was able to obtain the abrupt phase difference curve of the GMR device versus the incident angle.

A mho type phase comparator relay guideline using phase comparison technique for a power system

This paper presents a mho distance relay simulation based on the phase comparison technique using a typical electrical power systems analysis software for two cases: when the operation state is close to the static voltage limit and during a dynamic perturbation in the system. The paper evaluates the impedance variations caused by complex voltage values, the mho polarization, and the comparator operating region into the complex plane. In addition, the paper found the information for the dynamic perturbations from the outputs considering a mid-term stability program. The simulation of the mho-phase comparator in the static voltage proximity limit detects unit distance elements with impedance measured close to reach the threshold in the steady-state. Dynamic mho simulations in the complex plane are successfully tested by plotting time phase difference curves on the comparator input signals. Relay programmers can use these curves to analyze other phase comparators applications and the corresponding models in the complex plane.

Effect of Shoulder Diameter on the Force Generation, Microstructure and Mechanical Properties of Friction Stir-Brazed Aluminium Alloy and Copper with Ultrahigh Rotation Speed

Friction stir brazing with ultrahigh rotation speed was applied to 6061 aluminium alloy–pure copper lap joints with the aid of zinc foil. The effects of different shoulder diameters from 7 to 15 mm on the microstructure and mechanical properties of Al/Cu FSB joints were investigated along with the temperature and resistance of the friction tool. The oscillation of forward resistance and lateral force was related to the flow of the plastic metal and contributed to obtain a good appearance during the welding process. From the appearance of the welded joints, it was obvious that the phase difference between the forward resistance and lateral force had a significant influence on the joint characteristics. Obvious scale-like ripples appeared on the weld area when a sharp angle in the phase difference curve existed. Additionally, with a lower axial force and oscillation assistance, a satisfactory joint could be obtained. The results of the shear strength of the brazed joint showed that the shoulder with a 12 mm diameter yielded the highest shear strength. Meanwhile, the zinc foil in the middle melted completely and formed finely dispersed CuZn5 Al–Zn eutectic structures at the Al–Cu interface.

Adaptive simultaneous algebraic reconstruction technique for retrieving refractive index profiles of optical fiber

An efficient adaptive simultaneous algebraic reconstruction technique (ASART) to calculate optical fiber refractive index profiles is proposed based on phase difference curves obtained by digital holography technique. We develop adaptive relaxation parameter (ARP) on simultaneous algebraic reconstruction technique (SART) to increase the convergence speed and improve the reconstruction accuracy. A formula of ARP is derived mathematically and multilevel scheme (MLS) is used to increase convergence speed in the first iteration. Experimental results show the proposed ASART convergences over 40% faster than SART and achieve significantly higher reconstruction accuracy. Experimental verification shows that ASART is more efficient than SART and filtered back projection in image reconstruction, especially with few projection views. The running time of ASART is much shorter than that of SART, and ASART needs fewer iteration numbers to obtain the same reconstruction effects. In addition, it can be used to measure optical fibers with various diameters that cannot be measured with S14 refractive index profiler (S14).

Sodankylä ionospheric tomography data set 2003–2014

Abstract. Sodankylä Geophysical Observatory has been operating a receiver network for ionospheric tomography and collecting the produced data since 2003. The collected data set consists of phase difference curves measured from COSMOS navigation satellites from the Russian Parus network (Wood and Perry, 1980) and tomographic electron density reconstructions obtained from these measurements. In this study vertical total electron content (VTEC) values are integrated from the reconstructed electron densities to make a qualitative and quantitative analysis to validate the long-term performance of the tomographic system. During the observation period, 2003–2014, there were three to five operational stations at the Fennoscandia sector. Altogether the analysis consists of around 66 000 overflights, but to ensure the quality of the reconstructions, the examination is limited to cases with descending (north to south) overflights and maximum elevation over 60°. These constraints limit the number of overflights to around 10 000. Based on this data set, one solar cycle of ionospheric VTEC estimates is constructed. The measurements are compared against the International Reference Ionosphere (IRI)-2012 model, F10.7 solar flux index and sunspot number data. Qualitatively the tomographic VTEC estimate corresponds to reference data very well, but the IRI-2012 model results are on average 40 % higher than that of the tomographic results.

Effects of order parameter self-consistency in as±−sjunction

The properties of Josephson tunneling between a single band s-wave superconductor and a two band $s_\pm$ superconductor are studied, in relation to recent experiments involving iron-based superconductors. We study a single junction and tune the order parameter (OP) phase difference across the junction. We find a variety of behaviors which are characterized by their energy-phase difference relation. The system is modeled on a lattice and treated in self-consistent mean field approximation. We also study a loop structure made with s-wave and $s_\pm$ parts with two junctions between the parts. The phase of the order parameter is then controlled by a magnetic flux threading the loop. Our analysis suggests four types of junction behaviors which are characterized by the dependence of the junction energy on the phase difference between the s-wave and the $s_\pm$ superconductors. The energy vs. phase difference curve has either one minimum at $\Delta\phi = 0,\pi$ or somewhere in between, or a double minimum structure. This leads to four different behaviors in a loop structure as a function of the flux threaded through the loop.

Velocity measurements of cylindrical surface waves with a large aperture line-focus acoustic transducer

Acoustic microscopy has been widely applied in the measurements of the mechanical properties. However, the measurement of wave velocity on a curved cylindrical surface by acoustic microscopy was seldom reported. In this paper, we adopted a large aperture line-focus PVDF transducer and a defocusing measurement system to measure the velocity of a cylindrical surface waves. The theoretical model was established to study the relationship among the propagation path of surface waves, the geometric parameters of a transducer, and the diameter of a shaft specimen. Based on theoretical deduction and mathematical modeling, theoretical oscillation curves of phase difference were obtained. According to the improved V(f,z) analysis method, the V(f,z) curves were obtained through analyzing experimental data at different frequencies by Fourier transform. Then the surface wave velocity of the cylindrical tungsten steel specimen (Ø 20mm) could be determined by fitting the V(f,z) curves with the theoretical curves. The measurement results were consistent with the theoretical values, indicating that the measurement method was feasible. This study laid the basis for the ultrasonic measurement of the mechanical properties on the layer-coated cylinders.

New time-space-time optical packet switching node based on nonlinear polarization rotation of a semiconductor optical amplifier.

In this paper, we establish a simple model to analyze the semiconductor optical amplifier's (SOA) nonlinear polarization rotation (NPR) and acquire the variable curves of phase difference between TE and TM modes with bias current, pump power, probe power, and linewidth enhancement factor (LEF). The results indicate that the optical switch based on the SOA's NPR can be realized by changing the pump's optical power and the main operating parameters, such as bias current and hold beam power, and then the pump power can be determined. On this basis, a time-space-time (T-S-T) optical packet switching node is proposed, in which the SOA's NPR switch is the basic element. Then, the T-S and S-T experimental systems are set up, and the experimental results demonstrate that the proposed switch scheme can implement the optical switching function in accordance with the routing requirement. The signal-to-noise ratio (SNR) exceeds 20 dB, and the extinction ratio (ER) is more than 10 dB after being delayed and switched in the node.

Real-Time Dynamic Spectrum Analysis for Plasma Electron Density and Faraday Rotation Angle Measurement on HL-2A**supported by National Natural Science Foundation of China (Nos. 11375195 and 11275059) and the National Magnetic Confinement Fusion Science Program of China (Nos. 2013GB104003, 2014GB109001)

Electron density and Faraday rotation angle are important physical parameters in nuclear fusion research. To measure them simultaneously, the three-wave polarimeter/interferometer diagnostic system is applied. Both the final probe output signal and the reference signal contain three frequency components. The time-varying phase difference curve of each frequency component can be measured by the Real-time Dynamic Spectrum Analysis (RDSA) method based on Field-Programmable Gate Array (FPGA). The phase difference precision is better than 0.1° and the real-time feedback delay is less than 1 ms, which satisfy the requirements of HL-2A.

The Influence of Beam Polarization Degree on SPR Phase Sensor

The influence of incident beams polarization degree on the SPR phase sensor is theoretically and experimentally studied in this paper. The results indicate that the decrease of the polarization degree will lead to the phase difference curves jump decrease near the resonance angle for the ellipsometry method. Besides, the lower the polarization degree, the smaller the jump, which can also lead to reduced sensitivity of the SPR phase sensor. For example, the sensitivity with the polarization degree of 0.9 is 90% that of the polarization degree of 1.

Study on spectral deviations of high-order optical fiber comb filter based on polarization-diversity loop configuration

In this paper, we investigate optical factors that may cause deviations of experimentally observed output spectra from theoretically predicted ones in a high-order optical fiber comb filter based on a polarization-diversity loop configuration. They include the wavelength dependency of half-wave plates (HWPs) contained in the filter for wavelength switching and the weak birefringence of single-mode fibers (SMFs) that connect optical components comprising the filter. The wavelength dependence of the HWPs is considered using the phase difference curve of a commercial HWP, which is a function of the wavelength of an incident light. In order to examine the effect of the SMF birefringence on the spectral characteristics of the high-order comb filter, the SMF is modeled as a low birefringence fiber whose principal axes are arbitrarily oriented with a certain small birefringence value. It is concluded from the calculation results that the SMF birefringence rather than the wavelength dependency of HWPs strongly affects the spectral characteristics of the filter including an extinction ratio, wavelength location, and spectral shape of the filter channel.

Determination of effective complex refractive index of a turbid liquid with surface plasmon resonance phase detection

The dependence of the surface plasmon resonance (SPR) phase difference curve on the complex refractive index of a sample in Kretschmann configuration is discussed comprehensively, based on which a new method is proposed to measure the complex refractive index of turbid liquid. A corresponding experiment setup was constructed to measure the SPR phase difference curve, and the complex refractive index of turbid liquid was determined. By using the setup, the complex refractive indices of Intralipid solutions with concentrations of 5%, 10%, 15%, and 20% are obtained to be 1.3377+0.0005 i, 1.3427+0.0028 i, 1.3476+0.0034 i, and 1.3496+0.0038 i, respectively. Furthermore, the error analysis indicates that the root-mean-square errors of both the real and the imaginary parts of the measured complex refractive index are less than 5x10(-5).

Study on the Two‐Dimension Full‐Parameter Inverse Method of the Electromagnetic Propagation Resistivity Logging

AbstractThe multiple propagation resistivity (MPR) tool of the Baker‐Hughes INTEQ is the widely used electromagnetic propagation resistivity logging tool. It has four phase difference curves and four amplitude ratio curves. With it as an example, the application of the two‐dimension inverse method to the electromagnetic propagation resistivity logging data in vertical well is presented. Because the sensitivity of logging response to layer's boundary is much higher than that to other formation parameters, so how to accurately pick up layer's boundary is important. With the method described in this paper, we begin by picking the layer's boundaries from the highest resolution curve with the characteristic recognition method, and perform vertical one‐dimension inversion for the shallow and deep detection phase difference curves. Utilizing this result to construct the initial model for two‐dimension inversion, we carried out the full‐parameter inversion of MPR data by using an improved damping regularized Gauss‐Newton optimization algorithm. The satisfying inversion result is obtained for the two typical 23‐layer models. The inversion result can significantly improve the quality of MPR interpretation. In addition, it is found that the inversion results from only five curves are nearly the same to the results from eight curves.

Plane-parallel biaxial plates as polarization interferometers

Plane-parallel biaxial plates as polarization interferometers. Knowing the refractive indices and the directions of the rays inside a birefringent crystal, it is possible to calculate the positions of the images formed, when a non-parallel light beam incides on it. We part from general expressions for images in plane-parallel plates of any type of medium and we use vectorial expressions for the incident and refractive rays and waves in both interfaces. From them, we obtained the interference patterns which are observed when the plate is placed between two crossed polarizers. This experimental device constitutes a polarization interferometer. In order to find the shape of the interference patterns, we superposed the wave's fronts emerging from the images determining, in this way, the phase difference curves of phase constant on a screen.

Theoretical study of harmonic injection locking of millimeter wave harmonic gunn oscillators

Harmonic injection locking behavior of millimeter wave second harmonic Gunn oscillators is studied based on an equivalent circuit model. A large signal model of Gunn device in harmonic mode operation is employed. Injection locking curves of voltage amplitude and phase difference between injected current and harmonic voltage are calculated by means of describing function technique. Stability of the locked harmonic oscillators is also investigated. It is revealed that the harmonic locking bandwidth is much smaller than that of fundamental wave oscillators and is closely related to the susceptance slope parameter of fundamental wave circuit. It is also found that the stable region is smaller than that of fundamental wave oscillators. Some conclusions have been made for the application of harmonic injection locking technique.

Multiple Frequency Tympanometry

Three methods for compensating multiple frequency acoustic admittance measurements for ear canal volume were studied in 26 men with normal middle ear transmission systems. Peak compensated static acoustic admittance (magnitude of y) and phase angle (phi) were calculated from sweep frequency tympanograms (226-1243 Hz in 113 Hz increments). Of the procedures used to compensate for volume in rectangular form, the ear canal pressure used to estimate volume had the largest effect on the estimate of middle ear resonance. Median resonance was 800 Hz for admittance measurements compensated at 200 daPa versus 1100 Hz for measurements compensated at -350 daPa. The remaining two methods, compensation of susceptance only versus both susceptance and conductance and compensation using the minimum volume versus separate volumes at each frequency, did not affect estimates of middle ear resonance. Estimates of middle ear resonance from compensated phase angle measurements also were compared with estimates of resonance from admittance and phase difference curves. Although resonance could not be estimated from the phase difference curve, resonance estimated from the admittance difference curve agreed with the estimate from compensated phase angle.