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Recently, a novel wireless flat-panel detector with auto-exposure control has become available. This study aimed to elucidate the potential advantages of the new detector over conventional detectors through a comprehensive analysis of the physical image quality characteristics. Measurements were conducted on two models: new (720C) and conventional (710C) versions; this assessment was performed by assuming the beam quality for bedside chest radiography, utilizing a portable device for X-ray exposure. The detective quantum efficiency (DQE) was computed based on the presampled modulation transfer function (MTF) and normalized noise power spectrum. The validity of the DQE results was verified through the visualization of the analog blurring components and a detailed analysis of the noise components. The spatial frequency at which the presampled MTF value reached 10% was 5.2 cycles/mm for 720C and 3.9 cycles/mm for 710C. The full width at half-maximum of the spatial spreading of analog components was estimated at 0.09 mm for 720C and 0.14 mm for 710C by the visualization. Regarding the DQE, 720C was superior under low-dose conditions despite no significant differences being observed under high-dose conditions. The new detector demonstrated superior resolution characteristics compared with the conventional detector and an improvement in the DQE under low-dose conditions. However, similar to the conventional detector, a significant dose dependence caused by a structural factor was confirmed for the DQE. These results suggest the existence of an appropriate dose range for maximizing detector performance and provide insights crucial for optimization tasks in the X-ray imaging. [ABSTRACT FROM AUTHOR]

Acoustic emission, AE, belonging to a rubber-like deformation in a martensitic state after the stabilization aging of the stress-induced martensite (SIM aging) of Ni51Fe18Ga27Co4 single crystals in compression, were investigated. AE activity in the plateau regions of the stress–strain loop is due to a massive reorientation from the variants produced by SIM aging to the variants preferred by the compressive stress (perpendicular to the stress used in SIM aging) and vice versa. For unloading, the large AE activity just at the knee point of the stress–stain curve is attributed to the difficulty of the re-nucleation of the SIM aging-stabilized martensite variant. The amplitude, peak energy, and area of signals can be described by power-like distributions and the characteristic exponents are in good agreement with data obtained in other alloys. Power law cross-correlations between the energy, E, and amplitude, A, as well as between the area, S, and the amplitude, A, were also analyzed. It was found that the exponents are given by 3 − φ as well as 2 − φ , respectively, with φ ≅ 0.7. Normalized universal temporal shapes of avalanches (i.e., the U A   versus t A 1 − φ plots, where U is the detected voltage) for a fixed area scale very well together. The tail of the normalized temporal shape decays more slowly than the theoretical prediction, which can be attributed to an intrinsic absorption of AE signals and/or to the overlap of sub-avalanches. [ABSTRACT FROM AUTHOR]

Changes in the surrounding environment, if transmitted to the electron microscope, are frequently perceived as noise that diminishes the quality of the images. However, in fact, 'noises' contain rich information about the environment. This work reports a very rare event where aberration‐corrected HAADF‐STEM images were acquired during the impact of seismic waves, resulted from a mild earthquake. By analysing these images, we found that the drift and vibration of the sample are detectable and quantifiable. Despite many potential challenges, this work demonstrates the utilisation of electron microscopes in detecting and monitoring seismic waves with high spatial resolution, which may lead to unique applications in the low‐frequency regime. LAY DESCRIPTION: Electron microscopes, as precision instruments with high spatial resolution, have proven to be invaluable in areas such as material characterisation and electron beam lithography. However, a crucial prerequisite for achieving optimal performance is placing them in a mechanically and electromagnetically quiet environment, ideally free from vibrations and electromagnetic interference. In other words, electron microscopes are highly sensitive to subtle disturbances in their surroundings. This work presents the first reference to aberration‐corrected scanning transmission electron microscopy, which was expected to achieve sub‐angstrom resolution in imaging or distance measurement, under the influence of seismic waves. These seismic waves were generated by an earthquake of magnitude 4.3 that occurred 193 km away from the electron microscopes. Alongside image simulations, the direction and frequency of the vibrations affecting the images were evaluated, revealing a close relationship with the current anisotropic geometry of the side‐entry sample holder used in this study. Although the seismic waves were dampened before reaching the sample, the image analysis demonstrated the capability to detect vibrations of the sample at frequencies as low as a few hertz with an amplitude of the order of hundreds of picometres. One implication of this work, discussed in the paper, is the potential application of electron microscopes for vibration measurement in the low‐frequency regime, where seismic waves propagate further but traditional seismometers face challenges. [ABSTRACT FROM AUTHOR]

Electron microscopy is essential for examining materials and biological samples at microscopic levels, providing detailed insights. Achieving high‐quality imaging is often challenged by the potential damage high‐energy beams can cause to sensitive samples. This study compares scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to evaluate image quality, noise levels, and the ability to preserve delicate specimens. We used a modified SEM system with a transmitted electrons conversion accessory, allowing it to operate like a TEM but at lower voltages, thereby reducing sample damage. Our analysis included quantitative assessments of noise levels and texture characteristics such as entropy, contrast, dissimilarity, homogeneity, energy, and correlation. This comprehensive evaluation directly compared traditional TEM and the adapted SEM system across various images. The results showed that TEM provided images with higher clarity and significantly lower noise levels, reinforcing its status as the preferred method for detailed studies. However, the modified SEM system also produced high‐quality images at very low acceleration voltages, which is crucial for imaging samples sensitive to high‐energy exposure. The texture metrics analysis highlighted the strengths and limitations of each method, with TEM images exhibiting lower entropy and higher homogeneity, indicating smoother and more uniform textures. This study emphasizes the importance of selecting the appropriate electron microscopy method based on research needs, such as sample sensitivity and required detail level. With its conversion accessory, the modified SEM system is a versatile and valuable tool, offering a practical alternative to TEM for various applications. This research enhances our understanding of the capabilities and limitations of SEM and TEM. It paves the way for further innovations in electron microscopy techniques, improving their applicability for studying sensitive materials. Research Highlights: Our study introduces a modified SEM adapter enabling TEM‐like imaging at reduced voltages, effectively minimizing sample damage without compromising image resolution.Through comparative analysis, we found that images from the modified SEM closely match the quality of traditional TEM, showcasing significantly lower noise levels.This advancement underscores the SEM's enhanced capability for detailed structural analysis of sensitive materials, broadening its utility across materials science and biology. [ABSTRACT FROM AUTHOR]

In this study, comprehensive noise analyses and optimization of two different capacitance multiplier structures have been presented. Capacitor multipliers, essential in low frequency applications due to capacitors' significant chip area requirement, play a significant role in high precision analog circuits. Noise impacts such filters by reducing the signal to noise ratio (SNR), increasing phase noise, and potentially causing distortion, which is critical in applications requiring high accuracy and stability, such as biomedical instrumentation, communication systems, and precision measurement devices. Therefore, thorough analysis and optimization of filter noise characteristics are essential for reliable operation in sensitive applications. Two capacitor multiplier structures are analyzed: the Multiple Output Voltage Differencing Transconductance Amplifier (MO-VDTA) based and the Multiple Output Current Differencing Transconductance Amplifier (MO-CDTA) based structures. The multiplication factor of the capacitor multiplier in basis of MO-VDTA varies between 120 and 750, depending on the IB value. This variation allows the cutoff frequency of the applied fi lt er to change between 2 kH z an d 12.4 kHz. The MO-CDTA based structure's multiplication factor varies between 400 and 1250 by changing the VGS voltage of the external PMOS. This structure has been used in a 2nd order low pass filter, with the cutoff frequency varying between 23.6 kHz and 91 kHz in conjunction with multiplication factor changing. In this respect, comprehensive noise analyses of the filter applications of these two structures have been examined to ensure reliable and efficient operation in sensitive applications. [ABSTRACT FROM AUTHOR]

TianQin (TQ) mission, the sole proposed gravitational wave detection project in geocentric orbit at an altitude of approximately 1 0 5 km, traverses diverse geomagnetic regions. This paper employs a hybrid model to simulate the ambient magnetic field along the TQ orbit, investigating magnetically-induced acceleration noise under varying satellite-sun angles (SSA) and solar activity levels. The highest noise level, approximately 1 0 − 16 ms − 2 Hz − 1 / 2 , occurs during transregional periods between the magnetosheath (MSH) and magnetotail (MTL). Noise within the MSH region is an order of magnitude lower than the former, with the MTL region exhibiting the lowest levels, although geomagnetic storms can equalize noise in both regions. Statistical analysis indicates that noise in the MTL region correlates with SSA and solar wind dynamic pressure, displaying a spectral characteristic of f − 1. 03 ± 0. 075 , while the MSH region shows a Kolmogorov turbulence spectrum near the flank and f − 0. 5 at the subsolar region. [Display omitted] • Efficient and accurate hybrid model for simulating ambient magnetic fields in far-Earth orbit. • Identified peak noise levels during transregional periods between the magnetosheath and magnetotail. • Demonstrated significant influence of solar activity and satellite-sun angles on magnetically-induced noise. • Provided essential insights on noise management for future geocentric gravitational wave detectors. [ABSTRACT FROM AUTHOR]

Circuit noise is a critical factor that affects the performances of an MEMS gyroscope. Therefore, it is essential to analyze and suppress the noises in the key analog circuits, which are the main noise sources. This study presents an optimized front-end readout circuit and noise suppression methods. First, the noise analysis of the front-end readout circuit is carried out with theoretical derivation to clarify the main noise contributors. To suppress the output noise, an improved readout circuit based on the T-resistor networks is proposed, and the corresponding noise equation is derived in detail. In addition, the noise analysis of the critical circuits of the detection and control system, such as the inverting amplifiers, the first-order low-pass filters, and the first-order high-pass filters, is carried out, and the noise suppression strategy with the optimization of the resistances and is proposed. Taking the inverting amplifier as an example, the theoretical derivation is verified by measuring and comparing the output noises of different resistance schemes. In addition, the output noises of the gyroscope before and after circuit optimization are measured. Experimental results demonstrate that the output noise with the circuit optimization is reduced from 60 μV/Hz1/2 to 30 μV/Hz1/2 and the bias instability is reduced from 3.8 deg/h to 1.38 deg/h. In addition, the ARW is significantly improved from 0.035 deg/h1/2 to 0.018 deg/h1/2, which indicates that the proposed noise analysis and suppression methods are effective and feasible. [ABSTRACT FROM AUTHOR]

Once upon a time the statistics of quantal release were fashionable: "n" available vesicles (fusion sites), each with probability "p" of releasing a quantum. The story was not so simple, a nice paradigm to be abandoned. Biophysicists, experimenting with "black films," explained the astonishing rapidity of spike- induced release: calcium can trigger the fusion of lipidic vesicles with a lipid bilayer, by masking the negative charges of the membranes. The idea passed away, buried by the discovery of NSF, SNAPs, SNARE proteins and synaptotagmin, Munc, RIM, complexin. Electrophysiology used to be a field for few adepts. Then came patch clamp, and multielectrode arrays and everybody became electrophysiologists. Now, optogenetics have blossomed, and the whole field has changed again. Nice surprise for me, when Alvarez de Toledo demonstrated that release of transmitters could occur through the transient opening of a pore between the vesicle and the plasma-membrane, no collapse of the vesicle in the membrane needed: my mentor Bruno Ceccarelli had cherished this idea ("kiss and run") and tried to prove it for 20 years. The most impressive developments have probably regarded IT, computers and all their applications; machine learning, AI, and the truly spectacular innovations in brain imaging, especially functional ones, have transformed cognitive neurosciences into a new extraordinarily prolific field, and certainly let us imagine that we may finally understand what is going on in our brains. Cellular neuroscience, on the other hand, though the large public has been much less aware of the incredible amount of information the scientific community has acquired on the cellular aspects of neuronal function, may indeed help us to eventually understand the mechanistic detail of how the brain work. But this is no more in the past, this is the future. [ABSTRACT FROM AUTHOR]

AbstractNoise signals obtained from local power range monitors and average power range monitors are routinely used for extracting stability information for boiling water reactors. The stability parameters of decay ratio (DR) and natural frequency are produced by signal processing algorithms. While theoretically a dynamical system like a reactor core composed of coherently coupled components possesses a unique DR, noise measurements from different detectors have been reported in several published works to produce different DRs, creating the impression that a DR is not unique at a given operating state but rather is space dependent. This paper is an attempt to reconcile theory with measurements and resolve the space-dependent DR paradox that was encountered afresh in the course of designing a new high-fidelity online stability monitor. As such, the issue of space dependence could not be overlooked as attributable to variability within the uncertainty of noise analysis algorithms. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the impact of classical optical communications in quantum key distribution (QKD) over hollow-core fiber (HCF), multi-core fiber (MCF) and single-core fiber (SCF) and propose wavelength allocation schemes to enhance QKD performance. Firstly, we theoretically analyze noise interference in QKD over HCF, MCF and SCF, such as spontaneous Raman scattering (SpRS) and four-wave mixing (FWM). To mitigate these noise types and optimize QKD performance, we propose a joint noise suppression wavelength allocation (JSWA) scheme. FWM noise suppression wavelength allocation and Raman noise suppression wavelength allocation are also proposed for comparison. The JSWA scheme indicates a significant enhancement in extending the simultaneous transmission distance of classical signals and QKD, reaching approximately 100 km in HCF and 165 km in MCF under a classical power per channel of 10 dBm. Therefore, MCF offers a longer secure transmission distance compared with HCF when classical signals and QKD coexist in the C-band. However, when classical signals are in the C-band and QKD operates in the O-band, the performance of QKD in HCF surpasses that in MCF. This research establishes technical foundations for the design and deployment of QKD optical networks. [ABSTRACT FROM AUTHOR]

Traditional automated offset detections on global navigation satellite system (GNSS) station coordinate time series still cannot fully replace manual detections in practical applications due to their high false positive detection rates. We developed preliminary and enhanced offset detection approaches and tested them against the solutions from the International GNSS service 2nd and 3rd data reprocessing campaigns (Repro2 and Repro3). Their manually detected offset recordings in International Terrestrial Reference Frame (ITRF) 2014 and ITRF2020 are used as evaluation criteria. In the preliminary approaches, stochastic models based on covariance matrix, white noise model, and white noise plus flicker noise model of both univariate and multivariate are studied. Although we achieved true positive, false positive, and false negative (TP, FP, FN) rates of (0.44, 0.40, 0.16) for Repro2 and (0.42, 0.44, 0.13) for Repro3, the preliminary automated detections still lead to many false positive detections. Thus, based on the preliminary approaches, and ancillary data, an enhanced detection approach is proposed. Enhanced detections significantly reduce 56% ~ 80% false positive detections compared to preliminary approaches. As a result, for Repro3, the optimal overall performance is attained with (TP, FP, FN) rates of (0.57, 0.25, 0.18), along with a detection rate of 75%; for Repro2, the rates are (0.58, 0.20, 0.22), accompanied by a 73% detection rate. The current enhanced approach may serve as a supplementary or reference to manual detection, although still not being perfect. Furthermore, 20 manually detected unknown offsets in ITRF2020 are found to correspond to some known events (13 earthquakes and 7 equipment changes); 34 automated detections that correspond to known events but are not collected in ITRF2020 are manually checked as offsets (14 earthquakes and 20 equipment changes). [ABSTRACT FROM AUTHOR]

The paper presents the noise analysis of a MEMS and ASIC readout integrated circuit (ROIC) constituting the accelerometer developed in the frame of the InnoReh project, aiming at the development of methods for monitoring patients with imbalance disorders. Several experiments were performed at different temperatures and in different configurations: ROIC alone, ROIC with emulated parasitic capacitances, MEMS and ROIC in separate packages, and MEMS and ROIC in a single package. Many noise/interference sources were considered. The results obtained experimentally were compared to the results of theoretical investigations and were within the same order of magnitude, although in practice, the observed noise was always greater than the theoretical estimation. The paper also includes an in-depth analysis to explain these differences. Moreover, it is argued that, in terms of noise, the MEMS sensing element, and not the ROIC, is the quality-limiting factor. [ABSTRACT FROM AUTHOR]

A new network of 16 broadband seismic stations is operational in the northern Chhattisgarh region to monitor the seismicity arising in the otherwise seismically quiescent zone. Ambient noise is comprehensively analyzed to evaluate station performance and validate the data quality. Power spectral densities are computed for all stations, comparing ambient noise levels against global limits for data from November 2022 to December 2023. Results indicate that noise levels consistently fall within global noise limits. The study emphasizes the pronounced effect of instrumental tilt on the horizontal components of broadband seismometers. Spatial variation of ambient noise levels across various period bands of the noise spectrum highlights the contribution of diverse noise sources such as anthropogenic activities, surface waves, body waves, and barometric effects. Seasonal variations in short-period, microseism, and long-period bands reveal temporal variation of noise levels. Diurnal variation in the short-period band indicates a prominent effect of cultural noise. Furthermore, the proximity of seismic stations to major mining areas induces high noise levels in the very short-period band during blasting activities compared to non-blasting periods. Our study thus explores the variability of the ambient noise environment while validating the robustness and stability of the seismic installation across the study region.

Acoustic emission, AE, belonging to a rubber-like deformation in a martensitic state after the stabilization aging of the stress-induced martensite (SIM aging) of Ni51Fe18Ga27Co4 single crystals in compression, were investigated. AE activity in the plateau regions of the stress–strain loop is due to a massive reorientation from the variants produced by SIM aging to the variants preferred by the compressive stress (perpendicular to the stress used in SIM aging) and vice versa. For unloading, the large AE activity just at the knee point of the stress–stain curve is attributed to the difficulty of the re-nucleation of the SIM aging-stabilized martensite variant. The amplitude, peak energy, and area of signals can be described by power-like distributions and the characteristic exponents are in good agreement with data obtained in other alloys. Power law cross-correlations between the energy, E, and amplitude, A, as well as between the area, S, and the amplitude, A, were also analyzed. It was found that the exponents are given by 3−φ as well as 2−φ, respectively, with φ≅0.7. Normalized universal temporal shapes of avalanches (i.e., the UA versus tA1−φ plots, where U is the detected voltage) for a fixed area scale very well together. The tail of the normalized temporal shape decays more slowly than the theoretical prediction, which can be attributed to an intrinsic absorption of AE signals and/or to the overlap of sub-avalanches.

The Taiji program is dedicated to the detection of middle and low-frequency gravitational waves, targeting the 0.1 mHz to 1 Hz frequency band. The project requires an acceleration residual sensitivity of 3 × 10−15 ms−2/Hz1/2, which necessitates a capacitance sensing resolution of 1 aF/Hz1/2 for the capacitive sensing system within the specified frequency range. The noise level of the resonant bridge significantly influences the resolution. Addressing the challenges in enhancing transformer performance parameters in existing resonant capacitance bridges and the constraints on improving the characteristics of resonant capacitance bridges, this study introduces a novel approach to reduce bridge thermal noise without optimizing existing parameters. The simulation results demonstrate that this scheme can reduce the noise to 0.7 times the original level and further reduce bridge thermal noise when other parameters affecting noise are optimized. This not only mitigates the demands for other performance parameters but also increases the range of maximum acceptable resonant frequency deviations and reduces its sensitivity to such variations. Experimental validation confirms that the proposed scheme effectively reduces noise by 0.7 times and improves the resolution of capacitance sensing to 0.6 aF/Hz1/2, thereby advancing the Taiji program gravitational wave detection capabilities. [ABSTRACT FROM AUTHOR]

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Once upon a time the statistics of quantal release were fashionable: “n” available vesicles (fusion sites), each with probability “p” of releasing a quantum. The story was not so simple, a nice paradigm to be abandoned. Biophysicists, experimenting with “black films,” explained the astonishing rapidity of spike-induced release: calcium can trigger the fusion of lipidic vesicles with a lipid bilayer, by masking the negative charges of the membranes. The idea passed away, buried by the discovery of NSF, SNAPs, SNARE proteins and synaptotagmin, Munc, RIM, complexin. Electrophysiology used to be a field for few adepts. Then came patch clamp, and multielectrode arrays and everybody became electrophysiologists. Now, optogenetics have blossomed, and the whole field has changed again. Nice surprise for me, when Alvarez de Toledo demonstrated that release of transmitters could occur through the transient opening of a pore between the vesicle and the plasma-membrane, no collapse of the vesicle in the membrane needed: my mentor Bruno Ceccarelli had cherished this idea (“kiss and run”) and tried to prove it for 20 years. The most impressive developments have probably regarded IT, computers and all their applications; machine learning, AI, and the truly spectacular innovations in brain imaging, especially functional ones, have transformed cognitive neurosciences into a new extraordinarily prolific field, and certainly let us imagine that we may finally understand what is going on in our brains. Cellular neuroscience, on the other hand, though the large public has been much less aware of the incredible amount of information the scientific community has acquired on the cellular aspects of neuronal function, may indeed help us to eventually understand the mechanistic detail of how the brain work. But this is no more in the past, this is the future.

The study evaluates Bangladesh–China relations through the ‘win-win cooperation’ lens and concludes with a ‘NOISE’ (Needs-Opportunities-Improvements-Strengths-Exceptions) analysis. Bangladesh, a South Asian developing nation, has maintained a strategic partnership with Beijing since the establishment of their diplomatic ties. However, the relationship gained exceptional momentum after Bangladesh’s inclusion in the Belt and Road Initiative (BRI). Bangladesh’s need for growth-necessary financing and China’s massive foreign investment outlook have contributed to the growth of their economic engagements. The analysis suggests that the Bangladesh–China relationship exhibits ‘win-win cooperation’ dynamics. The study identified the significant trade gap, loan agreements, and disbursement delays, along with others, challenging the solid Bangladesh–China bilateral economic interactions. The Rohingya refugee crisis resolve and geopolitical competition among major powers are two non-bilateral issues that could potentially impact future Dhaka–Beijing relations. Overcoming the existing barriers could position Bangladesh–China relations as a model for smaller-major power bilateral relations, particularly for developing nations. It is a desk research by design. The findings of this study may provide insights to policymakers in addressing the existing barriers to meet future needs.

• White noise domains in VLBI position time series. • White and flicker noise amplitudes show a pattern that depends on latitude. • Colored noise significantly impacts the estimation of velocity and its uncertainty. Identification of the optimal noise model for space geodetic time series is crucial for various studies in geodynamics and geodesy. However, the position time series of Very Long Baseline Interferometry (VLBI) are typically irregularly sampled. There is no clear evidence from previous studies to support that the Maximum Likelihood Estimate (MLE) method can allow for stable and reliable noise estimates for irregularly sampled data. To address this issue, we first conducted simulation studies. Results indicate that when the number of data points in the VLBI position time series reaches 300, reliable noise estimations result can be obtained using the MLE. We also found that the higher proportion of white noise a station has, the less influences the data gaps would be on noise estimations. Second, we apply the MLE to investigate the noise properties in the 32 VLBI position time series. About 12 (37.5%) stations exhibit pure white noise, and 15 (46.9%) stations display a combination of white noise and flicker noise. For these stations, the median amplitudes of white noise in the East, North, and Up components are 3.9, 4.6, and 11.9 mm, respectively. Moreover, white and flicker noise amplitudes show a latitude-dependent pattern, with stations located in the southern hemisphere and low latitudes (0-30°N) in the northern hemisphere exhibiting higher noise amplitudes. The remaining approximately 5 stations (15.6%) have the optimal noise model of power law noise with the mean spectral index of −0.32, −0.36, and −0.53 for the East, North, and Up components, respectively. Simply assuming pure white noise can significantly affect velocity uncertainty estimates when compared to using a noise model that includes colored noise. The velocity uncertainty will be underestimated by a factor of 2.9 on average. The effects of a small proportion of colored noise in VLBI data on velocity uncertainty estimation can be ignored only when the time series length exceeds 32.6 years. Additionally, the choice of different noise model can lead to a maximum difference of 0.84 mm for the annual signal of the Up component. [ABSTRACT FROM AUTHOR]

This study presents two quantum broadcast protocols for the transmission of two qubits utilizing cluster states as the quantum channel to two receivers. In the first simplified case of the protocol, two-qubit cluster states are transmitted using an eight-qubit quantum channel. In the generalized scheme, users receive 2n-qubit cluster states via 8n-qubits quantum channel. The mathematical description of both protocols are described in details. Furthermore, we investigate and analyze the effect of amplitude-damping, phase-damping and bit-flip noisy channels on the proposed protocol. [ABSTRACT FROM AUTHOR]

We propose a method that enables the precise determination of the number of atoms in a Dick-noise-free optical lattice clock, by effectively addressing quantum projection noise. Our approach relies on conducting stability measurements at three distinct parameter sets, allowing us to differentiate between quantum projection noise, photon shot noise, and technical noise. Importantly, it enables accurate extraction of the atom number, even in the presence of photon shot noise and technical noise. We utilize numerical simulations to validate our approach, optimize the modulation parameters for minimal uncertainty, and investigate the impact of atom number fluctuations on the determinacy of our results. The numerical results show the validity of our method and demonstrate an estimated uncertainty in the atom number that is below 4% with 6.7 h measurement, provided that the standard deviation of atom number fluctuation is kept below 0.14 times the average atom number. [ABSTRACT FROM AUTHOR]

In recent years, micromachined microphones have evolved into versatile transducers for gas-sensing applications in the fields of both direct and indirect photoacoustics. However, their noise properties have not yet caught much attention. In this contribution, we present an analysis of the noise spectrum of a MEMS microphone and show how it may be employed as a gas-sensing tool and to characterize photoacoustic detectors. The results highlight the potential to determine the speed of sound, ambient temperature, and gas composition via Fourier analysis of the microphone noise. [ABSTRACT FROM AUTHOR]

This paper describes the design of a low-noise, high-speed readout-integrated circuit for use in InGaAs infrared focal plane arrays, and analyzes the working principle and noise index of the pixel circuit in detail. The design fully considers the dynamic range, noise, and power consumption of the pixel circuit in which a capacitance transimpedance amplifier structure is adopted as the input stage circuit, and chip fabrication via an XFAB 0.18 µm CMOS process is successfully realized. The ROIC adopts monolithic integration and implements various functions, such as windowing, subsampling, and different integration and readout modes. The ROIC reached an array scale of 32 × 32, a frame rate of 100 Hz, and a readout rate of 20 Mbps with an analog power consumption of less than 52 mW. The measurement results show that the input reference noise can be reduced to 143 e- via the CDS, and the fully customized scheme has certain advantages in the research of high-performance ROICs. [ABSTRACT FROM AUTHOR]

High‐speed and highly sensitive infrared photodetectors are regarded as one of the most essential components in modern photonic devices and technology because of constantly emerging application scenarios. In this paper, an ultrafast and extremely low noise mid‐infrared (MIR) photodetector is reported at both room and cryogenic temperatures by leveraging the high‐mobility 2D electron gas (2DEG) at the polar CdTe/PbTe heterostructure interface. The detector simultaneously exhibits a peak detectivity of ≈4.2 × 1011 Jones with rapid response in the order of 10 ns, which is substantially superior to the state‐of‐the‐art 2DEG MIR detectors made of 2D layered materials. The ultrafast response with extremely low noise of the 2DEG photodetector is attributed to the unique band alignment at the interface. The practical infrared imaging application is further showcased using the 2DEG MIR detector by revealing the fine features of a MIR radiation target. This work highlights the promising prospect of utilizing the unique 2DEG interface in the field of high‐speed and highly sensitive MIR detection. [ABSTRACT FROM AUTHOR]

The Fourier transform infrared (FTIR) spectrometer is widely used for spectrum analysis and radiation intensity measurement. In this work, a pyrometer with the temperature measurement range of 800°C to 1200°C is developed based on the FTIR spectrometer, and the calibration of the instrument coefficients using a standard radiation source is performed. On this basis, the readout noise and shot noise in the spectral signal are analyzed, and a detailed quantitative evaluation of the influences of two kinds of noise on the temperature measurement accuracy is also carried out in this work. Experimental results show that the temperature deviation caused by the two kinds of noise is less than 1°C when the wavelength is within the range of 2.0 to 5.4 μm. However, when the wavelength is greater than 5.4 μm, the maximum temperature deviation caused by the readout noise and shot noise can reach about 12°C and 18°C, respectively. In view of this, a Kalman filter method is introduced in this work to reduce temperature fluctuations caused by these noises, where the maximum fluctuation can be reduced from 83.9°C to 6.1°C with this filter method. These experimental results can provide a valuable guidance for the general-purpose calibration and assessment of the FTIR-based pyrometer. [ABSTRACT FROM AUTHOR]

In this paper, the influence of classical signals on quantum key distribution (QKD) is studied over multi-core fiber (MCF) when optical amplifiers exist. Firstly, the long-distance simultaneous transmission architectures of QKD and classical signals are proposed based on advanced asymmetric sending or not sending QKD (SNS-QKD) and classical Bennett–Brassard 1984-QKD (BB84-QKD), and the segment length between optical amplifiers can be adjusted according to requirement. Then, theoretical models of spontaneous Raman scattering noise and four-wave mixing noise are established based on the proposed architectures. Next, the calculation models of the secure key rate under the influence of noises from classical signals are derived. Finally, the experimental results show that the theoretical models match well with the experimental photons, and the maximum difference between experimental and simulated noise photons is less than 2.6 dB. Simulation results show that the performance of asymmetric SNS-QKD is better than that of BB84-QKD architecture when classical signals and quantum signals are transmitted in different cores of MCF.

Interior permanent magnet synchronous motors (IPMSMs) are widely utilized due to their high power density. However, noise and vibration issues are often encountered in these motors. While researchers have extensively investigated individual aspects such as noise, vibration, and heat generation in PMSMs, there has been a lack of comprehensive studies examining the interrelationships among these factors. In this paper, a novel approach is proposed for predicting vibration by considering the radial force in the air gap as the exciting force, while also accounting for the changes in the permanent magnet (PM) characteristics caused by heat generation during motor operation. The method involves decomposing and identifying vibration components associated with each vibration mode and predicting noise based on the sound radiation efficiency of each mode. By constructing a vibration map based on current and temperature at a specific frequency, the components most affected by current variations and PM characteristics can be identified. This allows for the proposal of design improvements aimed at reducing vibration. Furthermore, by comparing the vibration map with the noise map, it is confirmed that vibration serves as a source of noise and influences its generation. However, it is found that vibration and noise are not strictly proportional. Overall, a comprehensive analysis of the correlations between vibration, noise, and other factors in IPMSMs is presented in this study. The proposed method and findings contribute to the understanding of the complex dynamics involved and provide valuable insights for the design of quieter and more efficient motor systems. [ABSTRACT FROM AUTHOR]

This article explores the Hardware-Efficient Quantum Search Algorithm and compares it with other well-known counterparts. Escalating the count of qubits may elevate susceptibility to errors, particularly in iterative algorithms such as Grover’s. Conversely, Noisy-Intermediate-Scale-Quantum (NISQ) computers encounter limitation in the number of gates necessary for excecution of any quantum queries. Thus, we utilize hardware-efficient quantum search algorithm for further investigation due to its optimized circuit depth. Moreover, the Qiskit library and Matlab are used for validation of the analysis. Furthermore, the noise effects, encompassing phase-damping (PD) and amplitude-damping (AD) noises, are explored to present a comparative analsysis of various search algorithms. [ABSTRACT FROM AUTHOR]

Observations from permanent GNSS stations are actively used for the research and monitoring of geodynamic processes. Today, with the use of modern scientific programs and IGS products, it is possible to determine GNSS station coordinates and velocities at the level of a few millimeters. However, the scientific community constantly faces the question of increasing the accuracy of coordinate definitions to obtain more reliable data in the study of geodynamic phenomena. One of the main sources of errors is systematic measurement errors. To date, the procedure for their removal is still incomplete and imperfect. Also, during the processing of long-term GNSS measurements, it was found that the coordinate time series, after the removal of trend effects, are also characterized by seasonal variations, mainly of annual and semi-annual periods. We estimated the daily coordinate time series of 10 permanent GNSS stations in the central-eastern part of Europe from 2001 to 2019 and calculated the seasonal variation coefficients for these stations. The average value of the coefficients for the annual cycle for the N, E, and H components is −0.7, −0.2, and −0.7 mm, and for the semi-annual cycle the average value is 0.3, 0.4, and −0.5 mm. The obtained coefficients are less than 1 mm, which is why it can be argued that there is no seasonal component in the coordinate time series or that it is so small that it is a problematic task to calculate it. This practical absence of a seasonal component in long-term time series of GNSS coordinates, in our opinion, is partly compensated by the use of modern models of mapping functions (such as VMF3) for zenith tropospheric delays instead of the empirical GMF. To test the obtained results, we calculated the coefficients of seasonal variations for the sub-network of GNSS stations included in the category of the best EPN stations—C0 and C1. The values of the coefficients for the stations of this network are also less than 1 mm, which confirms the previous statement about the absence of a seasonal component in the long-term time series of coordinates. We also checked the presence of seasonal changes in the time series using the well-known decomposition procedure, which showed that the seasonal component is not observed because the content does not exceed 10% for additive decomposition and 20% for multiplicative decomposition. [ABSTRACT FROM AUTHOR]

We use quantum computers to test the foundations of quantum mechanics through quantum algorithms that implement some of the experimental tests as the basis of the theory's postulates. These algorithms can be used as a test of the physical theory under the premise of perfect hardware or as a test of the hardware under the premise that quantum theory is correct. In this work, we show how the algorithms can be used to test the efficacy of a quantum computer in obeying the postulates of quantum mechanics. We study the effect of different types of noise on the results of experimental tests of the postulates. A salient feature of this noise analysis is that it is deeply rooted in the fundamentals of quantum mechanics as it highlights how systematic errors affect the quantumness of the quantum computer. [ABSTRACT FROM AUTHOR]

In this paper, a new approach for capacitance measurement for electrical capacitance tomography (ECT) sensors is proposed. The method is based on the digital processing of the time-domain voltage measurements at the sensor electrodes. Furthermore, a robust capacitance estimation algorithm is developed to convert the measured voltage time-series to inter-electrode capacitances. The proposed measurement technique simplifies the electronic design of the ECT sensor and is suitable for use in applications requiring a compact device with a fast scan time. The accuracy and sensitivity of the method are investigated numerically and experimentally using a prototype sensor. In particular, the sensitivity of the estimated capacitance to measurement noise levels is analyzed in detail. Additionally, an analysis of the parameters that affect the accuracy of estimated capacitances is carried out from which we are able to demonstrate that the method is immune to effects such as stray capacitances between the electrodes and the ground. A prototype sensor with an open curved geometry on a millimeter scale is used to test the method empirically. Experimental results obtained for measurements with mineral oil and water are shown and compared against capacitances obtained using a physics-based forward model of the sensor. The inter-electrode capacitances in the range of tens of femtofarads to a few picofarads are estimated and a close match with the forward model results is obtained. [ABSTRACT FROM AUTHOR]

This article introduces two controlled quantum broadcast protocols which they utilize 6-qubit and 6n-qubit (generalized scheme) cluster states as the quantum channel, respectively. The proposed protocols involve Alice broadcasting a defined transition state to the recipients under Charlie's control. Simulations conducted on the IBMQ platform and Qiskit library demonstrate the efficacy of the proposed protocols for random input states and various measurement shots. The impact of different types of quantum noises on the protocol are analyzed, and the fidelity metric is employed to evaluate the quality of broadcasted states over a noisy channel. Furthermore, suggestions regarding security risks and the robustness of the proposed protocols under various attack scenarios are presented in this article. [ABSTRACT FROM AUTHOR]

Objectives: Real time precise point positioning(RT-PPP) technology can realize one-way timing with sub-nanosecond precision and daily stability of 1×10-14 level. Clock steering affects the stability of the receiver's output time-frequency signal, however, inappropriate clock steering parameters can degrade the short-term stability of the receiver's oscillator. Methods: To combine the short-term stability of the oscillator and the long-term stability of the RT-PPP, we propose a phase-locked loop clock steering model for the RT-PPP time-frequency receiver. The noises of the system are analyzed. And the parameter design method of the second-order phase-locked loop is proposed. Experiments were carried out with the clock steering model and designed parameters used in the RT-PPP time-frequency receiver. Results: Experimental results show that the frequency stability of the RT-PPP time-frequency receiver is 4.344 4×10-12 at 1 s, 1.102 9×10-14 at 1 d, the frequency stability of the time intervals shorter than 300 s can get close to the free-running Rubidium clock, the frequency stability of the time intervals longer than 300 s can get close to the RT-PPP. Conclusions: The proposed clock steering model and parameter design method can well realize the combination of the oscillator's short-term stability and the RT-PPP's long-term stability. [ABSTRACT FROM AUTHOR]

To develop a generalized formulation for multi-echo gradient-echo-based chemical species separation for all MR signal models described by a weighted sum of complex exponentials with phases linear in the echo time. Constraints between estimation parameters in the signal model were abstracted into a matrix formulation of a generic parameter gradient. The signal model gradient was used in a parameter estimation algorithm and the Fisher information matrix. The general formulation was tested in numerical simulations and against literature and in vivo results. The proposed gradient-based parameter estimation and experimental design framework is universally applicable over the whole class of signal models using the matrix abstraction of the signal model-specific parameter constraints as input. Several previous results in magnetic-field mapping and water-fat imaging with different models could successfully be replicated with the same framework and only different input matrices. A framework for generalized parameter estimation in multi-echo gradient-echo MR signal models of multiple chemical species was developed and validated and its software version is freely available online.

Cellular Ca2+ signals are often constrained to cytosolic micro- or nano-domains where stochastic openings of Ca2+ channels cause large fluctuations in local Ca2+ concentration (Ca2+ 'noise'). With the advent of TIRF microscopy to image the fluorescence of Ca2+-sensitive probes from attoliter volumes it has become possible to directly monitor these signals, which closely track the gating of plasmalemmal and ER Ca2+-permeable channels. Nevertheless, it is likely that many physiologically important Ca2+ signals are too small to resolve as discrete events in fluorescence recordings. By analogy with noise analysis of electrophysiological data, we explore here the use of statistical approaches to detect and analyze such Ca2+ noise in images obtained using Ca2+-sensitive indicator dyes. We describe two techniques - power spectrum analysis and spatio-temporal correlation - and demonstrate that both effectively identify discrete, spatially localized calcium release events (Ca2+ puffs). Moreover, we show they are able to detect localized noise fluctuations in a case where discrete events cannot directly be resolved.

INTRODUCTION: Power grid blackouts occur frequently, which significantly impacts social impact. Because these accidents are dynamic and random, predicting and evaluating them is challenging. OBJECTIVES: To explore the complexity of the power grid itself, analyzes the critical changes of the self-organizing model during power grid fault, extracts the data characteristics related to the steady-state maintenance of abnormal systems, and puts forward an effective outage prediction model. METHODS: Starting with cluster analysis, The authors can reduce data fluctuation and eliminate noise interference to optimize data. The evaluation indexes of initial fault occurrence possibility and fault propagation speed in the power grid are constructed. RESULTS: The validation of the outage forecasting model has produced promising results, achieving 96.4% forecasting accuracy and a meager error rate. In addition, the evaluation index developed in this study accurately reflects the possibility and spread speed of power outage accidents. CONCLUSION: The research proves the feasibility of establishing an outage prediction model based on the power grid system data characteristics. The model has high accuracy and reliability and is a valuable tool for power outage research and judgment.

This study includes the properties and installation stages of the microseismic network planned to be installed in a geothermal field in Turkey, which is currently producing electricity, in order to monitor the induced seismicity that will occur due to production and re-injection wells. The results of how the optimum microseismic monitoring network should be installed, the installation studies and the noise analysis of the station locations are given for this and similar geothermal fields. 7 borehole type seismometers were placed in wells drilled 65 meters deep and microseismic records of the field were obtained. The leading field equipment is SARA-SS10BHV three-component (3C) borehole type short-period velocity seismometers, and the analog data were digitized with 24-bit SL06 brand recorders. In data analysis, high frequency, low energy and small amplitude microseismic events were dealt within passive seismic records. Therefore, noise analysis is the most important step of the network installation. In the noise analysis studies, the background noise at the locations where the microseismic network stations will be deployed was determined by measurements from both on the surface and through the well, and then the results were compared with each other. According to the results, it has been determined that the noise level in the well is very low compared to the surface and this is at a suitable level for microseismic monitoring networks. [ABSTRACT FROM AUTHOR]

We propose a method that enables the precise determination of the number of atoms in a Dick-noise-free optical lattice clock, by effectively addressing quantum projection noise. Our approach relies on conducting stability measurements at three distinct parameter sets, allowing us to differentiate between quantum projection noise, photon shot noise, and technical noise. Importantly, it enables accurate extraction of the atom number, even in the presence of photon shot noise and technical noise. We utilize numerical simulations to validate our approach, optimize the modulation parameters for minimal uncertainty, and investigate the impact of atom number fluctuations on the determinacy of our results. The numerical results show the validity of our method and demonstrate an estimated uncertainty in the atom number that is below 4% with 6.7 h measurement, provided that the standard deviation of atom number fluctuation is kept below 0.14 times the average atom number.