Cumulative Phase Research Articles

Real-time detection algorithm of object motion state based on frequency modulated continuous wave radar

<sec>Real time detection of object motion is widely used in industrial activities and daily life. The contactless measurement is a flexible way, which has no effect on the state of movement of the object. Compared with the optical, ultrasonic and laser sensors, microwave radar has the advantages of high measurement accuracy and being unaffected by the environment such as smoke, dust, fog, and rain. </sec><sec>The frequency modulated continuous wave (FMCW) radar is a widely used radar system, the echo of which contains abundant information, and there is no blind zone in the range because the transmitter and receiver work at the same time. The algorithm of movement detection of FMCW radar is commonly based on the peak estimation of signal spectrum, in order to achieve high accuracy, it is necessary to increase the frequency and bandwidth, resulting in high hardware complexity, a large amount of calculation, poor real-time response and poor anti-jamming ability. The proposed algorithm is based on the discrete Fourier transform with specific frequency of the beat signal. The real part and imaginary part of discrete Fourier transform are superposed in two perpendicular directions, and the resultant trajectory is approximately elliptical. The relative displacement of the object is proportional to the cumulative phase change of the corresponding points on the ellipse, the phase of each trajectory point can be calculated to restore the motion state of the object. The proposed algorithm does not need Fourier transform for the beat signal of each chirp, so the time complexity is low. The beat signal of the static object is processed into a fixed direct-current signal, which has no influence on the measurement of the moving object, therefore the algorithm has the ability to resist the interference of the static object. The measurement is limited to relative motion, because the phase obtained is relative. It has great potential applications in the fields of measuring relative displacement, such as mechanical vibration frequency, vital signal detection, mechanical arm control, etc.. </sec><sec>An experimental setup with a center frequency of 24 GHz, bandwidth of 0.15 GHz and frequency modulation period of 4 ms is used to test the hypothesis. The experimental results are in good agreement with the theoretical results. The displacement measurement accuracy is 0.27 mm, and the linearity is 0.05% with 500 mm as the displacement measurement range. The measurement accuracy of velocity is 1.11 mm/s.</sec>

Comparative Analysis of Systemic and Tumor Microenvironment Proteomes From Children With B-Cell Acute Lymphocytic Leukemia at Diagnosis and After Induction Treatment.

Among the childhood diseases, B-cell acute lymphocytic leukemia (B-ALL) is the most frequent type of cancer. Despite recent advances concerning disease treatment, cytotoxic chemotherapy remains the first line of treatment in several countries, and the modifications induced by such drugs in the organism are still poorly understood. In this context, the present study provided a comparative high-throughput proteomic analysis of the cumulative changes induced by chemotherapeutic drugs used in the induction phase of B-ALL treatment in both peripheral blood (PB) and bone marrow compartment (BM) samples. To reach this goal, PB and BM plasma samples were comparatively analyzed by using label-free proteomics at two endpoints: at diagnosis (D0) and the end of the cumulative induction phase treatment (D28). Proteomic data was available via ProteomeXchange with identifier PXD021584. The resulting differentially expressed proteins were explored by bioinformatics approaches aiming to identify the main gene ontology processes, pathways, and transcription factors altered by chemotherapy, as well as to understand B-ALL biology in each compartment at D0. At D0, PB was characterized as a pro-inflammatory environment, with the involvement of several downregulated coagulation proteins as KNG, plasmin, and plasminogen. D28 was characterized predominantly by immune response-related processes and the super expression of the transcription factor IRF3 and transthyretin. RUNX1 was pointed out as a common transcription factor found in both D0 and D28. We chose to validate the proteins transthyretin and interferon-gamma (IFN-γ) by commercial kits and expressed the results as PB/BM ratios. Transthyretin ratio was augmented after induction chemotherapy, while IFN-γ was reduced at the end of the treatment. Considering that most of these proteins were not yet described in B-ALL literature, these findings added to understanding disease biology at diagnosis and highlighted a possible role for transthyretin and IFN-γ as mechanisms related to disease resolution.

Evolution of inspiralling neutron star binaries: Effects of tidal interactions and orbital eccentricities

Neutron star (NS) binaries formed dynamically may have significant eccentricities while emitting gravitational waves (GWs) in the LIGO/VIRGO band. We study tidal effects in such eccentric inspiralling NS binaries using a set of hybrid equations. The NS is modelled as a compressible ellipsoid, which can deform nonlinearly due to tidal forces, while the orbit evolution is treated with the post-Newtonian (PN) theory up to 2.5-PN order. We find that in general, the tidal interaction can accelerate the inspiral, and cause orbital frequency and phase shifts. For circular inspirals, our calculations reproduce previous linear result at large binary separations, but incorporate the dynamical response of the NS at small separations. For eccentric inspirals, the frequency and phase shifts oscillate considerably near pericenter passages, and the oscillating amplitudes increase with eccentricities. As a result, the GW phase is also significantly influenced by the tidal effect. At merger, the cumulative GW phase shift can reach more than 10 radians (for typical NS mass $1.4M_\odot$ and radius 11.6 km), much larger than the circular inspiral case. Although the event rate of eccentric NS mergers is likely low, the detection of such mergers could provide a useful constraint on the NS equation of state.

Effects of treated sugar mill effluent and rice straw on substrate properties under milky mushroom (Calocybe indica P&C) production: Nutrient utilization and growth kinetics studies

Abstract In this work, we evaluated the potential of treated sugar mill effluent (SME) as a moistener of rice straw substrate for laboratory cultivation of milky mushroom (Calocybe indica P&C). Five different concentrations of SME including, 0% (control using normal water supply) 25, 50, 75, and 100% were tested to enrich the rice straw substrate. Laboratory experiments were performed under controlled temperature (32.5 °C) and humidity (74.0%). The results showed that substrate enrichment with SME significantly increased the nutrient composition of rice straw substrate which further enhanced the C. indica production. After cultivation of C. indica, the maximum removal of substrate nutrients including, organic carbon (36.05%), NO 3 − -N (37.41%), Na + (26.19%), K + (9.80%), PO 4 3 − -P (9.33%), SO 4 2 − (38.65%), Ca 2 + (28.19%), Mg 2 + (37.50%), Cu 2 + (43.70%), Fe 3 + (36.41%), Mn 2 + (35.62%), and Zn 2 + (36.13%) was observed using 50% SME enrichment. The maximum flush yield and bioefficiency were 127.2 g/kg substrate and 75.3% with maximum nutrient uptake rates, respectively within the same treatment. The modified Gompertz model gave the best predicted cumulative mushroom biomass production (y: 148.7 g/kg) and lag phase (0.1070 days) with a good coefficient of determination (R2 ≥ 0.9900), respectively. This work represented the sustainable utilization of treated SME for enhanced production of C. indica while reducing freshwater and fertilizer inputs.

Subretinal Fibrosis Detection Using Polarization Sensitive Optical Coherence Tomography.

PurposeSubretinal fibrosis (SRFib) is an important cause of permanent loss-of-vision diseases with submacular neovascularization, but a reliable diagnostic method is currently missing. This study uses polarization-sensitive optical coherence tomography (PS-OCT) to detect SRFib within retinal lesions by measurement of its birefringent collagen fibers.MethodsTwenty-five patients were enrolled with retinal pathology in one or both eyes containing (1) suspected SRFib, (2) lesions suspected not to be fibrotic, or (3) lesions with doubtful presence of SRFib. All eyes were evaluated for SRFIb using conventional diagnostics by three retinal specialists. PS-OCT images were visually evaluated for SRFib based on cumulative phase retardation, local birefringence, and optic axis uniformity.ResultsTwenty-nine eyes from 22 patients were scanned successfully. In 13 eyes, SRFib was diagnosed by all retinal specialists; of these, 12 were confirmed by PS-OCT and one was inconclusive. In nine eyes, the retinal specialists expected no SRFib, which was confirmed by PS-OCT in all cases. In seven eyes, the retinal specialists’ evaluations were inconsistent with regard to the presence of SRFib. PS-OCT confirmed the presence of SRFib in four of these eyes and the absence of SRFib in two eyes and was inconclusive in one eye.ConclusionsIn 21 out of 22 eyes, PS-OCT confirmed the evaluation of retinal specialists regarding the presence of SRFib. PS-OCT provided additional information to distinguish SRFib from other tissues within subretinal neovascular lesions in 6 out of 7 eyes.Translational RelevancePS-OCT can identify and quantify SRFib in doubtful cases for which a reliable diagnosis is currently lacking.

Multi-frequency point supported LLRF front-end for CiADS wide-bandwidth application

The China initiative Accelerator Driven System, CiADS, physics design adopts $162.5 \,\mathrm{MHz}$, $325 \,\mathrm{MHz}$, and $650 \,\mathrm{MHz}$ cavities, which are driven by the corresponding radio frequency (RF) power system, requiring frequency translation front-end for the RF station. For that application, a general-purpose design front-end prototype has been developed to evaluate the multi-frequency point supported design feasibility. The difficult parts to achieve the requirements of the general-purpose design are reasonable device selection and balanced design. With a carefully selected low-noise wide-band RF mixer and amplifier to balance the performance of multi-frequency supported down-conversion, specially designed local oscillator (LO) distribution net to increase isolation between adjacent channels, and external band-pass filter to realize expected up-conversion frequencies, high maintenance and modular front-end general-purpose design has been implemented. Results of standard parameters show an $R^2$ value of at least $99.991\%$ in the range of $-60 \sim 10\,\mathrm{dBm}$ for linearity, up to $18\,\mathrm{dBm}$ for P1dB, and up to $89\,\mathrm{dBc}$ for crosstalk between adjacent channels. The phase noise spectrum is lower than $80\,\mathrm{dBc}$ in the range of $0 \sim 1\,\mathrm{MHz}$, and cumulative phase noise is $0.006^\circ$; amplitude and phase stability are $0.022\%$ and $0.034^\circ$, respectively.

Phase effects in coherently stimulated down-conversion with a quantized pump field

We investigate the effect of the cumulative phase on the photon statistics of the three-mode state whose evolution is described by the trilinear Hamiltonian $\hat{H}_{I}=i\hbar\kappa\big(\hat{a}\hat{b}\hat{c}^{\dagger}-\hat{a}^{\dagger}\hat{b}^{\dagger}c\big)$, wherein the pump is taken to be quantized (and prepared in a coherent state) and the signal and idler modes are initially seeded with coherent states. We provide a brief review of the two-mode squeezed coherent states generated by non-degenerate coherently-stimulated parametric down-conversion, whereby the nonlinear crystal is driven by a strong classical field. The statistics of the resulting two mode state have been shown to depend greatly on the cumulative phase $\Phi=\theta_{s}+\theta_{i}-2\phi$ where $\theta_{s\left(i\right)}$ are the signal(idler) coherent state phases and $2\phi$ is the classical pump phase. Using perturbation theory, we analytically show for short times how the photon statistics and entanglement properties of the resultant state depends strictly on this phase combination. We also present numerical results of the relevant quantities to show the evolution of the three modes and provide a qualitative analysis of the steady state valid for long times.

Tidal effects in eccentric coalescing neutron star binaries

Dynamically formed compact object binaries may still be eccentric while in the LIGO/Virgo band. For a neutron star (NS) in an eccentric binary, the fundamental modes (f-modes) are excited at pericenter, transferring energy from the orbit to oscillations in the NS. We model this system by coupling the evolution of the NS f-modes to the orbital evolution of the binary as it circularizes and moves toward coalescence. NS f-mode excitation generally speeds up the orbital decay and advances the phase of the gravitational wave signal from the system. We calculate how this effect changes the timing of pericenter passages and examine how the cumulative phase shift before merger depends on the initial eccentricity of the system. This phase shift can be much larger for highly eccentric mergers than for circular mergers, and can be used to probe the NS equation of state.

Inductive measurement and encoding of k-space trajectories in MR raw data.

The objective of this study was to concurrently acquire an inductive k-space trajectory measure and corresponding imaging data by an MR scanner. 1D gradient measures were obtained by digital integration, regularized using measured gradient coil currents and recorded individually by the scanner concurrently with raw MR data. Gradient measures were frequency modulated into an RF signal receivable by the scanner, yielding a k-space trajectory measure from the cumulative phase of the acquired data. Generation of the gradient measure and frequency modulation was performed by previously developed custom, versatile circuitry. For a normal echo planar imaging (EPI) sequence, the acquired k-space trajectory measure yielded slightly improved image quality compared to that obtained from using the scanner's estimated eddy current-compensated k-space trajectory. For a spiral trajectory, the regularized inductive k-space trajectory measure lead to a 76% decrease in the root-mean-square error of the reconstructed image. While the proof-of-concept experiments show potential for further improvement, the feasibility of inductively measuring k-space trajectories and increasing the precision through regularization was demonstrated. The approach may offer an inexpensive method to acquire k-space trajectories concurrently with scanning.

The formation mechanism of air pollution episodes in Beijing city: Insights into the measured feedback between aerosol radiative forcing and the atmospheric boundary layer stability.

Based on the high-resolution observation of meteorological factors profiles, particulate matter concentration and aerosol radiative forcing (ARF) from 25 August to 17 November 2018 in Beijing, the feedback between ARF and the atmospheric boundary layer (ABL) stability was systematically investigated during air pollution episodes. There was the initial explosive growth in particulate matter (PM) concentration that PM2.5 sharply increased from ~8μgm-3 to ~100μgm-3, with aerosol optical depth (AOD) increasing from ~0.25 to ~0.58. This was the transport phase dominated by the southerly winds. As PM increased, the high aerosol loading scattered more solar radiation cooling the earth-atmosphere system (ARF at the top of the atmospheric column (TOA): from ~5Wm-2 to ~-52Wm-2). Meanwhile, high aerosol loading absorbed more solar radiation and heated the atmospheric layer with ARF at the interior of the atmospheric column (ATM) increasing from ~21Wm-2 to ~42Wm-2. The absorption and scattering effects of aerosol together cooled the surface (ARF at the surface of the atmospheric column (SFC): from ~-16Wm-2 to ~-90Wm-2). Thus, the ABL stability rapidly increased in the following cumulative phase and heavy pollution phase with a strong temperature inversion (inversion depth of ~300-1000m) occurring. In turn, the persistent temperature inversion caused the significant accumulation of moisture (water vapor density of ~5-10gm-3) and pollutants, and PM were prone to physicochemical reactions in the high-humidity environment, further increasing PM. It was the constant feedback effect between ARF and the ABL stability that continually reduced atmospheric environmental capacity and aggravated air pollution (PM2.5 and AOD reaching ~95-125μgm-3 and ~1.38-1.75, respectively). Finally, the feedback was broken by dry, clean and strong north winds appearing in Beijing in the dissipation phase.

Impact of acetic acid in methane production from glycerol/acetic acid co-fermentation

Co-fermentation of glycerol and acetic acid in anaerobic digestion was set up to generate biogas in batch reactors under mesophilic condition, pH 7. The experiments were varied COD ratios of glycerol and acetic acid were varied with the total combined COD of 5,20 0 mg/L. The maximum methane yield was obtained from glycerol/acetic acid ratio of 6:4. The cumulative methane, production rate and lag phase were 240 mL, 14 mL hr−1, and 11 hr. The research indicated acetic acid boosted methane production when it was co-fermented with glycerol.

Quasi single-frame measurements with phase-stepped ESPI

Phase-stepped ESPI measurement techniques typically require the acquisition of sets of speckle images before and after specimen deformation. This process limits the use of the technique to quasi-static specimens. A novel technique is proposed here where speckle images are measured in a continuous phase-stepped sequence and where interpolation of nearby images is used to infer all four phase-stepped images corresponding to each measured image. This process effectively creates a single-frame ESPI measurement technique that is suitable for observing moving objects. Small phase changes measured by a high-speed camera are observed incrementally between successive images, with cumulative phase changes determined by summation. This approach avoids the need for phase unwrapping, and so retains an absolute zero phase datum. The sequence of small phase changes also preserves good correlation between successive measurements, thus enabling successful cumulative phase measurements over large specimen displacements, even into the mm range. The phase visibility at each pixel is available within every measured image, thereby enabling the use of pixel repair strategies if desired.

Depth-resolved birefringence imaging of collagen fiber organization in the human oral mucosa in vivo.

Stromal collagen organization has been identified as a potential prognostic indicator in a variety of cancers and other diseases accompanied by fibrosis. Changes in the connective tissue are increasingly considered for grading dysplasia and progress of oral squamous cell carcinoma, investigated mainly ex vivo by histopathology. In this study, polarization-sensitive optical coherence tomography (PS-OCT) with local phase retardation imaging is used for the first time to visualize depth-resolved (i.e., local) birefringence of healthy human oral mucosa in vivo. Depth-resolved birefringence is shown to reveal the expected local collagen organization. To demonstrate proof-of-principle, 3D image stacks were acquired at labial and lingual locations of the oral mucosa, chosen as those most commonly affected by cancerous alterations. To enable an intuitive evaluation of the birefringence images suitable for clinical application, color depth-encoded en-face projections were generated. Compared to en-face views of intensity or conventional cumulative phase retardation, we show that this novel approach offers improved visualization of the mucosal connective tissue layer in general, and reveals the collagen fiber architecture in particular. This study provides the basis for future prospective pathological and comparative in vivo studies non-invasively assessing stromal changes in conspicuous and cancerous oral lesions at different stages.

Large-Scale Genome Comparison Based on Cumulative Fourier Power and Phase Spectra: Central Moment and Covariance Vector

Genome comparison is a vital research area of bioinformatics. For large-scale genome comparisons, the Multiple Sequence Alignment (MSA) methods have been impractical to use due to its algorithmic complexity. In this study, we propose a novel alignment-free method based on the one-to-one correspondence between a DNA sequence and its complete central moment vector of the cumulative Fourier power and phase spectra. In addition, the covariance between the four nucleotides in the power and phase spectra is included. We use the cumulative Fourier power and phase spectra to define a 28-dimensional vector for each DNA sequence. Euclidean distances between the vectors can measure the dissimilarity between DNA sequences. We perform testing with datasets of different sizes and types including simulated DNA sequences, exon-intron and complete genomes. The results show that our method is more accurate and efficient for performing hierarchical clustering than other alignment-free methods and MSA methods.

Performance analysis of distributed transmit beamforming in presence of oscillator phase noise

This paper analyses the performance of distributed transmit beamforming in presence of oscillator phase noise. Average beampattern of arbitrary array is adopted here as performance index. In the analysis, the phase noise process of each node oscillator is described by a stationary model taking into account 1/f3 and 1/f2 shape single-sideband (SSB) spectrum. By using non-parametric kernel method, the average beampattern in presence of phase noise is derived and corresponding beampattern characteristics are evaluated. Theoretical analysis and simulation results show that the accumulated PN can result in the degradation of DTBF performance, which are also reflected in the change of beampattern characteristics, such as 3db width, 3db sidelobe region and average directivity. With the increase of time duration, the cumulative phase noise becomes greater and the degradation is more obvious.

Performance analysis of distributed transmit beamforming in presence of oscillator phase noise

This paper analyses the performance of distributed transmit beamforming in presence of oscillator phase noise. Average beampattern of arbitrary array is adopted here as performance index. In the analysis, the phase noise process of each node oscillator is described by a stationary model taking into account 1/f3 and 1/f2 shape single-sideband (SSB) spectrum. By using non-parametric kernel method, the average beampattern in presence of phase noise is derived and corresponding beampattern characteristics are evaluated. Theoretical analysis and simulation results show that the accumulated PN can result in the degradation of DTBF performance, which are also reflected in the change of beampattern characteristics, such as 3db width, 3db sidelobe region and average directivity. With the increase of time duration, the cumulative phase noise becomes greater and the degradation is more obvious.

Effects of Air Flowrate on the Combustion and Emissions of Blended Corn Straw and Pinewood Wastes

This research investigated the effects of the specific primary (under-fire) air flowrate (m˙air) on the combustion behavior of a 50–50 wt % blend of raw corn straw (CS) and raw pinewood wastes in a fixed-bed reactor. This parameter was varied in the range of 0.079–0.226 kg m−2 s−1, which changed the overall combustion stoichiometry from air-lean (excess air coefficient λ = 0.73) to air-rich (excess air coefficient λ = 1.25) and affected the combustion efficiency and stability as well as the emissions of hazardous pollutants. It was observed that by increasing m˙air, the ignition delay time first increased and then decreased, the average bed temperatures increased, both the average flame propagation rates and the fuel burning rates increased, and the combustion efficiencies also increased. The emissions of CO as well as those of cumulative gas phase nitrogen compounds increased, the latter mostly because of increasing HCN, while those of NO were rather constant. The emissions of HCl decreased but those of other chlorine-containing species increased. The effect of m˙air on the conversion of sulfur to SO2 was minor. By considering all of the aforesaid factors, a mildly overall air-rich (fuel-lean) (λ = 1.04) operating condition can be suggested for corn-straw/pinewood burning fixed-bed grate-fired reactors.

Feeding Time Entrains the Olfactory Bulb Circadian Clock in Anosmic PER2::LUC Mice

Circadian rhythms in many brain regions and peripheral organs can be entrained by daily feeding schedules. The set of feeding-related signals that entrain peripheral clocks are tissue specific and include nutrients, metabolic hormones and temperature. Signals that entrain neural circadian clocks to mealtime have yet to be established for any brain region. The olfactory bulb (OB) contains a robust circadian clock that can cycle independently of the suprachiasmatic nucleus (SCN) master pacemaker. We used PER2::LUC mice to evaluate the suitability of the OB for analysis of inputs that mediate entrainment of neural clocks by feeding schedules. Explants of SCN and OB from mice fed ad-libitum exhibited robust circadian rhythms of bioluminescence for three or more days in vitro, with rhythm peaks occurring late in the day and night, respectively. Mice restricted to a 4 h meal/day in the light period exhibited food anticipatory activity and a 6.3 h advance of the OB PER2::LUC rhythm. The cumulative phase shift of the OB rhythm increased gradually in OB explants harvested after 2–7 days of restricted feeding. In mice anosmic after nasal irrigation with zinc sulfate and fed ad-libitum for one week, OB phases were desynchronized. Group synchrony in anosmic mice was restored by restricted feeding. The OB circadian clock is food-entrainable, entrains gradually to a mid-day meal, and requires neither olfaction nor circadian signaling from olfactory sensory neurons. The OB can be used as a model system for analysis of input pathways by which circadian clocks in the brain entrain to daily mealtimes.

Vector Modulation by Laser and Electroabsorption Modulator With Digital Pre-Coding and Pre-Compensation

We present a method to achieve vector modulation of lightwave using an electroabsorption modulator intregrated laser. The laser section is used for direct phase modulation followed by an amplitude modulation of the electroabsorption modulator section in a cascade manner, which is an alternative method to conventional IQ modulator. To allow an improved phase demodulation, we propose a digital pre-compensation technique for a transmitter in optical coherent system for the first time, which includes a phase-balanced differential phase shift keying encoding and a digital domain pre-equalization filtering. The phase-balanced encoding technique applies parallel DC-balance coding with a phase-balanced symbol mapping, which results in a bounded cumulative phase and a constant statistical characteristic of the modulating signal in differential M-ary phase shift keying and M-ary quadrature amplitude modulation formats. The digital pre-equalization filter also compensates for the phase response of the laser section. Experimental results show that the pre-digital compensation technique allows the improved complex signal demodulation compared to conventional DQPSK modulation in a back-to-back setup.

Three-dimensional modelling and simulation of vibration marks on surface generation in ultra-precision grinding

Nowadays, most modelling work for ground surface topography is based on either abrasive kinematics (micro-level) or high-frequency vibration of the grinding wheel (macro-level) to predict surface quality or grinding performance, but there is a lack of a correlation model to relate these two levels together. In this research work, wheel shape with two radii and wheel synchronous vibration are modelled first for the interference of the tool edge in 3D space to reveal the evolution mechanism of surface waviness under different vibration conditions (phase shift from 0.0 to 1.0). Hence, a multi-scale model is established considering the diverse protrusion heights of the grits and incorporating the wheel shape and micro-vibration of the tool so as to explain the mechanism of the generation of the surface marks on the ground surface. The result shows that four principal residual marks are formed on the ground surface including spirals, tool feed marks, cumulative phase marks and abrasive grain scratches. The amount of surface waviness resulting from the tool unbalance is equal to the ratio of the rotating speed of the grinding wheel and the workpiece. The feed mark representing the tool locus and tool nose geometry is a spiral pattern from edge area to the machined center. The phase shift marks are caused by the phase accumulation effect. The grit scratches are related to the wheel geometry, kinematics and distribution of protrusion heights. In addition, the phase shift tends to increase the density of grinding marks, with a significant decrease when the phase shift is equal to 0.5. The surface generation model is further verified by a closed surface matching method, which shows the simulation results agree reasonably well with the grinding experiments.