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In this paper, we propose a novel compact statistical model for the low-frequency noise (LFN) of MOS devices with halo implants. The compact model is suited for the incorporation in modern models, such as BSIM, PSP, and EKV, and can be used to predict the dependence of the LFN of halo-implanted MOSFETs with bias, temperature, geometry, and technological parameters. This compact model is based on the physics-based random telegraph noise (RTN) model, previously published by our group. The previous model was simplified in analytical expressions dependent on parameters and on physical quantities already calculated in modern compact models. Following the physics-based model, the LFN compact model predicts the large bias dependence of the LFN statistics induced by the halo implants in long-channel devices. Moreover, we show for the first time that the halo implants also induce a large temperature dependence of the LFN statistics for devices operated near the weak inversion or saturation, and the proposed compact model predicts this dependence. [ABSTRACT FROM AUTHOR]

Electrostatically formed nanowire (EFN) transistor is a majority carrier silicon-on-insulator (SOI) device, operated in the depletion mode, with the conducting channel size and position modulated by surrounding gates. When operated in the subthreshold regime, the EFN transistor is an efficient temperature sensor. We present a novel EFN transistor design with a top gate, named gate-all-around EFN (GAA EFN), allowing increased temperature sensitivity. The new design enables the formation of the EFN conductive channel in the volume of the SOI device layer, far from the top and bottom silicon/oxide interfaces, thus reducing the noise level and increasing the temperature sensitivity to 13.3%/K. [ABSTRACT FROM AUTHOR]

The total-ionizing-dose response of few layer MoS2 transistors with ZrO2 or h-BN gate dielectrics is investigated under various bias conditions. Defects in MoS2 and surrounding dielectric layers significantly affect radiation-induced trapping. For devices with ZrO2 dielectrics, much larger negative Vth shifts and peak transconductance degradation are observed for irradiation under negative and ground bias than under positive bias. The h-BN devices exhibit positive threshold voltage shifts under negative-bias irradiation. For both ZrO2 and h-BN passivated devices, the peak transconductance degradation results from charge trapping at the surface of the MoS2 or in nearby oxides. Changes in defect energy distributions of MoS2 FETs during X-ray irradiation are characterized via temperature-dependent low-frequency noise measurements. Density functional theory calculations are performed to provide insight into the pertinent defects. [ABSTRACT FROM AUTHOR]

Low-frequency noise emitted by elevated viaducts in light rail transit lines has considerable adverse effects on inhabitants living nearby. Reliable prediction of the acoustic field radiating from the viaduct using forward numerical models is challenging because the model parameters that influence viaduct vibration are difficult to obtain. To avoid directly quantifying these parameters, such as wheel–rail combined roughness, an inverse method is presented to reconstruct the acoustic field using modal acoustic transfer vectors and the sound pressures at a small number of measurement points. First, a forward numerical method based on the train–track–bridge interaction analysis is performed to predict the structure-borne noise of a concrete box girder viaduct. Then, the calculated sound pressures are treated as virtual measurement results to illustrate the inverse method procedure. Both QR decomposition and singular value decomposition with Tikhonov regularisation are used in the inverse analysis. Third, the proposed inverse method is validated by comparing the sound pressure levels computed using the inverse method with the results simulated using the forward prediction method. Finally, the reliability of the inverse procedure is further validated through field tests of two U-shaped girder viaducts. [ABSTRACT FROM AUTHOR]

High-quality seismic data are the basis for stratigraphic imaging and interpretation, but the existence of random noise can greatly affect the quality of seismic data. At present, most understanding and processing of random noise still stay at the level of Gaussian white noise. With the reduction of resource, the acquired seismic data have lower signal-to-noise ratio and more complex noise natures. In particular, the random noise in the desert area has the characteristics of low frequency, non-Gaussian, nonstationary, high energy, and serious aliasing between effective signal and random noise in the frequency domain, which has brought great difficulties to the recovery of seismic events by conventional denoising methods. To solve this problem, an improved feed-forward denoising convolution neural network (DnCNN) is proposed to suppress random noise in desert seismic data. DnCNN has the characteristics of automatic feature extraction and blind denoising. According to the characteristics of desert noise, we modify the original DnCNN from the aspects of patch size, convolution kernel size, network depth, and training set to make it suitable for low-frequency and non-Gaussian desert noise suppression. Both simulation and practical experiments prove that the improved DnCNN has obvious advantages in terms of desert noise and surface wave suppression as well as effective signal amplitude preservation. In addition, the improved DnCNN, in contrast to existing methods, has considerable potential to benefit from large data sets. Therefore, we believe that it can open a new direction in the area of seismic data processing. [ABSTRACT FROM AUTHOR]

We investigated the effects of in situ silicon carbon nitride (SiCN) cap layer of AlGaN/GaN high-electron mobility transistors (HEMTs) on DC, capacitance-voltage (C-V) and low-frequency noise (LFN). The proposed device with SiCN cap layer exhibited enhanced drain current, reduced gate leakage current, low interface trap density (Dit), and high on/off ratio thanks to the passivation effect, compared to the device without SiCN cap layer. Both devices clearly showed 1/f noise behavior with carrier number fluctuations (CNF), regardless of the existence of SiCN cap layer. The proposed device presented the relative low trap density (Nit) and reduced access noise due to the effective surface passivation in source-drain access region compared to the device without SiCN cap layer. From the improved DC, C-V and noise results of the proposed device, the in situ SiCN cap layer plays an important role in the passivation layer and gate oxide layer in AlGaN/GaN HEMT.

• The position of interface traps along the channel has been evaluated in Junciotnless transistors. • The effect of traps on the low frequency noise depends on the surface potential. • In JNTs, the surface potential varies along the channel with drain/gate biases. • JNTs low frequency noise is more sensitive to trap centers close to the source side. • The lower surface potential close to the source enables traps to be occupied for a longer time. Differently from inversion mode MOS transistors, Junctionless Nanowires surface potential presents a strong dependence on the gate and drain biases, when the devices are biased in partial depletion. For that reason, the position of interface trap centers along the channel could have a significant influence on the electrical characteristics of the devices. Therefore, this work has evaluated how the position of a single interface trap along the channel can affect the low-frequency noise response of Junctionless Nanowire Transistors. It has been shown that the trap centers closer to the source side of the devices are more likely to degrade the noise characteristics than those located closer to the drain, which has been attributed to the lower surface potential in this region, enabling traps to be at the same state (occupied or empty) for a longer time interval. [ABSTRACT FROM AUTHOR]

[Display omitted] • 1. This study aims to elucidate the role of the OrHSF1 in responding to anthropogenic noise. • 2. Silencing of OrHSF1 resulted in suppression of Hsp70 expression. • 3. The HSF1-Hsp70 axis plays a crucial role in mediating anthropogenic noise-induced stress responses. To investigate the regulatory role of heat shock transcription factor 1 of sea slug Onchidium reevesii (OrHSF1) on Hsp70 expression in the sea slug under stress , the OrHSF1 gene was cloned and bioinformatics analysis was performed, then the gene and protein expressions by RNA interference (RNAi) mediated knockdown of OrHSF1 expression were measured to clarify the regulatory relationship between OrHSF1 and Hsp70 under low-frequency noise (LFN) stress. Our study was the first to clone a 1572 bp sequence of the OrHSF1 gene, with the sequence coding for amino acids (CDS) being 729 bp, encoding 243 amino acids. O. reevesii shared a close evolutionary relationship with mollusks such as the Aplysia californica. OrHSF1 gene is widely expressed in different tissues of sea slugs, with the highest expression in the intestine and the lowest in the reproductive glands. Furthermore, we used RNA interference (RNAi) as a tool to silence the OrHSF1 gene in the central nervous system (CNS) and the results indicated that gene silencing was occurring systematically in the CNS and the suppression of OrHSF1 expression by RNAi-mediated gene silencing altered the expression of Hsp70 ; besides, the expression trends of OrHSF1 gene and Hsp70 were consistent in the 3 and 5-day RNAi experiment. Moreover, in sea slugs injected with siHSF1 and exposed to LFN, the mRNA expression and protein expression of Hsp70 in the CNS were significantly decreased compared to the low-frequency noise group (P < 0.05). This study demonstrated that OrHSF1 regulates Hsp70 expression in marine mollusks under low-frequency noise, and HSF1-Hsp70 axis plays a key role in stress response. [ABSTRACT FROM AUTHOR]

[Display omitted] • HEMTs are very attractive candidates for 5G applications. • Low frequency noise were performed on AlGaN/GaN HEMTs with different channel orientation. • LF noise is an important tool for studying reliability of GaN-based HEMTs. • Flicker noise is due to trapping in the AlGaN barrier of High-Electron-Mobility Transistors. • Noise Power Spectral Density of AlGaN/GaN High-Electron-Mobility Transistors. The performance of AlGaN/GaN High-Electron Mobility Transistors (HEMTs) fabricated on 〈1 1 1〉 silicon substrates has been experimentally investigated, aiming to verify the effect of different channel orientations on the main electrical parameters, such as drain current (I D), threshold voltage, transconductance (g m), and Drain-Induced Barrier Lowering (DIBL). Moreover, the noise Power Spectral Density (PSD) with different channel orientations has also been characterized in linear operation. No noticeable differences on the electrical and noise PSD characteristics have been observed between the GaN channel orientations (0°, 90° and 45°). [ABSTRACT FROM AUTHOR]

Objectives: Evaluation of the effect of low-frequency noise (LFN) on the frequency of chromosomal aberrations in the bone marrow cells and on the content of low-molecular-weight DNA (lmwDNA) in the blood plasma of rats. Materials and Methods: A total of 96 male Wistar rats were exposed to either single (17 min session) or multiple (17 min session repeated five times a week for 13 weeks) LFN, with the maximum range below 250 Hz and the sound pressure levels (SPLs) at 120 and 150 dB, respectively. The rats in the control groups were not subjected to any impact. The frequency of chromosomal aberrations in the bone marrow cells and the levels of lmwDNA in the blood plasma were measured afterwards. Results: It has been detected that a single LFN exposure with either corresponding SPLs had a significant increase in the frequency of chromosomal aberrations (more than 10-fold) compared to the controls (0.9 ± 0.3%) and resulted in the appearance of dicentric chromosomes in the aberration spectrum, both of which are evident for the occurrence of deoxyribonucleic acid double strand breaks triggered by the exposure. Furthermore, the lmwDNA levels in the blood plasma measured the following day after a single LFN exposure were significantly higher (7.7- and 7.6-fold, respectively) than that in the control group (11.0 ± 5.4 ng/ml), and such levels were maintained higher (4.8- and 2.1-fold, respectively) in the week after a single LFN exposure for the SPL of 120 and 150 dB, respectively, compared to the control group (18.8 ± 1.6 ng/ml). Similar results were obtained from the group with multiple LFN exposures (36.4- and 22.4-fold, respectively) compared to the control (17.7 ± 1.7 ng/ml) and suggest the enhancement of cellular apoptosis as a result of the LFN impact. Conclusion: Presumably, the LFN may have possible mutagenic effects and cause massive cell death.

Nowadays, compact and reliable electronic devices including up-to-date ceramic micro-electro-mechanical systems require thick-film resistors with significantly reduced dimensions and stable and precise resistance values. For that reason, instead of standard laser trimming method, high voltage pulse trimming of thick-film resistors is being introduced. This method allows controlled and reliable resistance adjustment regardless of resistor position or dimensions and without the presence of cuts. However, it causes irreversible structural changes in the pseudorandom network formed during sintering causing the changes in conducting mechanisms. In this paper results of the experimental investigation of high voltage pulse trimming of thick-film resistors are presented. Obtained results are analyzed and correlations between resistance and low-frequency noise changes and changes in conducting mechanisms in resistors due to high voltage pulse trimming are observed. Sources of measured fluctuations are identified and it is shown that this type of trimming is a valid alternative trimming method to the dominant laser trimming. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III44003 and III45007]

AlxGa1−xN/GaN heterostructures with two kinds of Al composition were grown by metal organic chemical vapor deposition (MOCVD) on sapphire substrates. The Al compositions in the AlGaN barrier layer were confirmed to be 13% and 28% using high resolution X-ray diffraction (HRXRD). AlxGa1−xN/GaN high-electron mobility transistors (HEMTs) with different Al compositions were fabricated, characterized, and compared using the Hall effect, direct current (DC), and low-frequency noise (LFN). The device with high Al composition (28%) showed improved sheet resistance (Rsh) due to enhanced carrier confinement and reduced gate leakage currents caused by increased Schottky barrier height (SBH). On the other hand, the reduced noise level and the low trap density (Nt) for the device of 13% of Al composition were obtained, which is attributed to the mitigated carrier density and decreased dislocation density in the AlxGa1−xN barrier layer according to the declined Al composition. In spite of the Al composition, the fabricated devices exhibited 1/ƒ noise behavior with the carrier number fluctuation (CNF) model, which is proved by the curves of both (SId/Id2) versus (gm/Id)2 and (SId/Id2) versus (Vgs–Vth). Although low Al composition is favorable to the reduced noise, it causes some problems like low Rsh and high gate leakage current. Therefore, the optimized Al composition in AlGaN/GaN HEMT is required to improve both noise and DC properties.

We investigated the effects of GaN buffer resistance of AlGaN/GaN high-electron-mobility transistors (HEMTs) on direct current (DC), low-frequency noise (LFN), and pulsed I-V characterization performances. The devices with the highest GaN buffer resistance were grown on sapphire substrate using two-step growth temperature method without additional compensation doping. The proposed device exhibited the degraded off-state leakage current due to the improved GaN buffer quality compared to the reference devices with relative low buffer resistance, which is confirmed by high resolution X-ray diffraction (HRXRD). However, the proposed device with deep-level defects in GaN buffer layer showed the reduced hysteresis (∆Vth), increased breakdown voltage (BV), and enhanced pulse I-V characteristics. Regardless of GaN buffer resistance, all devices clearly showed 1/f behavior with carrier number fluctuations (CNF) at on-state but followed 1/f2 characteristic at off-state. From the 1/f2 noise characteristics, the extracted trap time constant (τi) of the proposed device can be obtained to be 10 ms, which is shorter than those of the reference devices because of the full compensation of deep-level defects in the GaN buffer layer.

The paper proposes a method of automatic detection of parameters of a distribution transformer (model, type, and power) from a distance, based on its low-frequency noise spectra. The spectra are registered by sensors and processed by a method based on evolutionary algorithms and machine learning. The method, as input data, uses the frequency spectra of sound pressure levels generated during operation by transformers in the real environment. The model also uses the background characteristic to take under consideration the changing working conditions of the transformers. The method searches for frequency intervals and its resolution using both a classic genetic algorithm and particle swarm optimization. The interval selection was verified using five state-of-the-art machine learning algorithms. The research was conducted on 16 different distribution transformers. As a result, a method was proposed that allows the detection of a specific transformer model, its type, and its power with an accuracy greater than 84%, 99%, and 87%, respectively. The proposed optimization process using the genetic algorithm increased the accuracy by up to 5%, at the same time reducing the input data set significantly (from 80% up to 98%). The machine learning algorithms were selected, which were proven efficient for this task.

This paper summarizes the presently available knowledge about the association between low-frequency noise and its effects on health. A database was constructed with a total of 142 articles published between 2016 and 2019 regarding low-frequency noise exposure and its effects on health. A total of 39 articles were analysed in depth. The articles were divided into categories according to the effects on human health addressed. Regarding the emitting source, there was a greater number of articles addressing issues related to sources of environmental noise and noise from wind turbines. As for the effects generated on human health, there was a greater number of articles referring to the effects on sleep disorders, discomfort, sensitivity to and irritability from noise, annoyance, hearing loss, and cardiovascular diseases, and these effects are analysed in more detail in the present article.

The A-weight sound level is difficult to evaluate the annoyed noise of the inverter air conditioner,so it is necessary to establish the sound quality and give objective evaluate parameters,such as loudness,sharpness,roughness,psychoacoustic annoyance etc. The sound quality software is developed to analyze outdoor noise of MIDEA inverter air conditioner and the competitive product; the main difference is low-frequency noise. Then,the"rock"noise and periodic"buzz"noise are analyzed in detail,and system dynamic balance and beat are main reasons. Some methods are obtained to eliminate the lowfrequency noise and can improve the sound quality. These methods can potentially become a powerful air conditioner sound evaluation tool in inverter air conditioner field.

Hardware neuromorphic systems are crucial for the energy-efficient processing of massive amounts of data. Among various candidates, hafnium oxide ferroelectric tunnel junctions (FTJs) are highly promising for artificial synaptic devices. However, FTJs exhibit non-ideal characteristics that introduce variations in synaptic weights, presenting a considerable challenge in achieving high-performance neuromorphic systems. The primary objective of this study is to analyze the origin and impact of these variations in neuromorphic systems. The analysis reveals that the major bottleneck in achieving a high-performance neuromorphic system is the dynamic variation, primarily caused by the intrinsic 1/f noise of the device. As the device area is reduced and the read bias (V Read ) is lowered, the intrinsic noise of the FTJs increases, presenting an inherent limitation for implementing area- and power-efficient neuromorphic systems. To overcome this limitation, an adaptive read-biasing (ARB) scheme is proposed that applies a different V Read to each layer of the neuromorphic system. By exploiting the different noise sensitivities of each layer, the ARB method demonstrates significant power savings of 61.3% and a scaling effect of 91.9% compared with conventional biasing methods. These findings contribute significantly to the development of more accurate, efficient, and scalable neuromorphic systems., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Two-dimensional (2D) transistors are promising for potential applications in next-generation semiconductor chips. Owing to the atomically thin thickness of 2D materials, the carrier scattering from interfacial Coulomb scatterers greatly suppresses the carrier mobility and hampers transistor performance. However, a feasible method to quantitatively determine relevant Coulomb scattering parameters from interfacial long-range scatterers is largely lacking. Here, we demonstrate a method to determine the Coulomb scattering strength and the density of Coulomb scattering centers in InSe transistors by comprehensively analyzing the low-frequency noise and transport characteristics. Moreover, the relative contributions from long-range and short-range scattering in the InSe transistors can be distinguished. This method is employed to make InSe transistors consisting of various interfaces a model system, revealing the profound effects of different scattering sources on transport characteristics and low-frequency noise. Quantitatively accessing the scattering parameters of 2D transistors provides valuable insight into engineering the interfaces of a wide spectrum of ultrathin-body transistors for high-performance electronics.

Background: Low-frequency noise may cause changes in cognitive function. However, there is no established consensus on the effect of low-frequency noise on cognitive function. Therefore, this systematic review and meta-analysis aimed to explore the relationship between low-frequency noise exposure and cognitive function., Methods: We conducted a systematic review and identified original studies written in English on low-frequency noise and cognition published before December 2022 using the PsycINFO, PubMed, Medline, and Web of Science databases. The risk of bias was evaluated according to established guidelines. A random-effects meta-analysis was performed where appropriate. To explore the association between low-frequency noise exposure and cognitive function, we reviewed eight relevant studies. These studies covered cognitive functions grouped into four domains: attention, executive function, memory, and higher-order cognitive functions. The data extraction process was followed by a random-effects meta-analysis for each domain, which allowed us to quantify the overall effect., Results: Our analysis of the selected studies suggested that interventions involving low-frequency noise only had a negative impact on higher-order cognitive functions (Z = 2.42, p = 0.02), with a standardized mean difference of -0.37 (95% confidence interval: -0.67, -0.07). A moderate level of heterogeneity was observed among studies (p = 0.24, I 2  = 29%, Tau 2  = 0.03)., Conclusions: Our study findings suggest that low-frequency noise can negatively impact higher-order cognitive functions, such as logical reasoning, mathematical calculation, and data processing. Therefore, it becomes important to consider the potential negative consequences of low-frequency noise in everyday situations, and proactive measures should be taken to address this issue and mitigate the associated potential adverse outcomes., (© 2024. The Author(s).)

Exposure to intense low-frequency sounds, for example inside tanks and armoured vehicles, can lead to noise-induced hearing loss (NIHL) with a variable audiometric pattern, including low- and mid-frequency hearing loss. It is not known how well existing methods for diagnosing NIHL apply in such cases. Here, the audiograms of 68 military personnel (mostly veterans) who had been exposed to intense low-frequency noise (together with other types of noise) and who had low-frequency hearing loss (defined as a pure-tone average loss at 0.25, 0.5 and 1 kHz ≥20 dB) were used to assess the sensitivity of three diagnostic methods: the method of Coles, Lutman and Buffin, denoted CLB, which depends on the identification of a notch or bulge in the audiogram near 4 kHz, and two methods specifically intended for diagnosing NIHL sustained during military service, the rM-NIHL method, which depends on the identification of a notch or bulge in the audiogram near 4 kHz and/or a hearing loss at high frequencies greater than expected from age alone, and the MLP(18) method based on a multi-layer perceptron. The proportion of individuals receiving a positive diagnosis for either or both ears, which provides an approximate measure of sensitivity, was 0.40 for the CLB method, 0.79 for the rM-NIHL method and 1.0 for the MLP(18) method. It is concluded that the MLP(18) method is suitable for diagnosing NIHL sustained during military service whether or not the exposure includes intense low-frequency sounds., Competing Interests: Declaration of Conflicting InterestsAuthors Moore and Cox write reports in relation to claims for compensation for NIHL.

Studies of noise properties of thick-film conducting lines from Au or PdAg conductive pastes on LTCC or alumina substrates are reported. Experiments have been carried out at the room temperature on samples prepared in the form of meanders by traditional screen-printing or laser-shaping technique. Due to a low resistance of the devices under test (DUTs), low-frequency noise spectra have been measured for the dc-biased samples arranged in a bridge configuration, transformer-coupled to a low-noise amplifier. The detailed analysis of noise sources in the signal path and its transfer function, including the transformer, has been carried out, and a procedure for measurement setup self-calibration has been described. The 1/f noise component originating from resistance fluctuations has been found to be dominant in all DUTs. The analysis of experimental data leads to the conclusion that noise is produced in the bends of meanders rather than in their straight segments. It occurs that noise of Au-based laser-shaped lines is significantly smaller than screen-printed ones. PdAg lines have been found more resistive but simultaneously less noisy than Au-based lines.

Low-frequency noise is used to estimate the quality of the gate stack for planar Ge nMOSFETs with different effective work function metals and cap layers. It is shown that replacing TiN by a TiAl-based metal gate will induce a significant decline of the threshold voltage ${V}_{T}$ and noise power spectral density, indicating the introduction of Al will induce an advantageous effect on the trap density in the underlying HfO2. Meanwhile, the application of a LaOx cap tends to reduce ${V}_{T}$ and the trap density in the gate oxide, which could attribute to the La in-diffusion in the gate stack. The 1/f noise analysis shows that the noise could mainly be associated with number fluctuations and correlated mobility fluctuations. [ABSTRACT FROM AUTHOR]

Ferromagnetic-core loop antennas with high-permeability core materials are typically used in size-constrained applications requiring the detection and reception of weak very low frequency and extremely low frequency signals. However, high-permeability materials are susceptible to saturation in the presence of strong magnetic fields such as those generated by power lines, in research laboratories, or through natural phenomena. Here, a system is presented that actively controls the magnetic flux in the core of the antenna by applying a control signal to an independent set of windings on the same core. This control signal is phase locked to the offending signal and the two signals destructively combine in the core. Our results show that it is possible to actively cancel the fundamental component of a strong interferer in the core of a high sensitivity ferromagnetic-core loop antenna and prevent core saturation. This approach eliminates signal distortion caused by magnetic saturation that passive signal cancellation or signal processing in the receiver do not. Thus, high-sensitivity ferromagnetic-core antennas can be used in applications where they were previously thought unsuitable. [ABSTRACT FROM AUTHOR]

In this study, a multifunctional acoustic metastructure is proposed to achieve both effective low-frequency sound isolation and acoustic energy harvesting. A metallic substrate with proof mass is adopted to generate the local resonant phenomenon for the purpose of overcoming the drawbacks of the previous rubber film-based acoustic metastructure; the latter usually requires an elaborate tension process. Numerical simulations show that the proposed structure exhibits excellent noise isolation performance in the low-frequency band. Meanwhile, the incident sound energy can be converted into electrical energy with the help of an added piezoelectric patch. Numerical simulation results indicate that the harvested energy can reach the mW level. The parameters' influence on the metastructure's vibro-acoustic and energy harvesting performance are discussed in detail. An optimized configuration is selected and used for experimental study. It is demonstrated that 0.21 mW electrical power at 155 Hz can be harvested by the proposed metastructure under 114 dB sound pressure excitation. [ABSTRACT FROM AUTHOR]

A new mechanism of low-frequency (LF) (<2 GHz) thermal noise generation in magnetoresistive readers is described and confirmed experimentally. A mechanical model of a bi-harmonic oscillator is simulated at finite temperature by a numerical analysis of the Langevin equation in order to illustrate the concept. Filtered LF waveforms strongly correlate with resonance amplitude fluctuations and expose 1/ $f$ -like spectra. We apply this learning to reader output waveforms, proving the presence of the phenomenon for both free layer and synthetic antiferromagnet resonance lines. The impact of spin-momentum transfer is also seen by virtue of different correlation coefficients at positive and negative bias current values. [ABSTRACT FROM AUTHOR]

Abstract Background Chronic exposure to industrial noise is known to affect biological systems, namely, by inducing fibrosis in the absence of inflammatory cells. In rat hearts exposed to this environmental hazard, we have previously found myocardial and perivascular fibrosis. The acoustic spectrum of industrial environments is particularly rich in high-intensity infrasound (<20 Hz), whose effects on the heart are unknown. We evaluated the morphological changes induced by IFS in rat coronaries in the presence and absence of dexamethasone. Methods Adult Wistar rats were divided into three groups: group A (GA)—IFS (<20 Hz, 120 dB)-exposed rats for 28 days treated with dexamethasone; group B (GB)—IFS-exposed rats; group C (GC)—age-matched controls. The midventricle was prepared for observation with an optical microscope using 100× magnification. Thirty-one arterial vessels were selected (GA 8, GB 10, GC 13). The vessel caliber, thickness of the wall, and perivascular dimensions were quantified using image J software. Mann–Whitney and Kruskal–Wallis tests were used to compare the groups for lumen-to-vessel wall (L/W) and vessel wall-to-perivascular tissue (W/P) ratios. Results IFS-exposed rats exhibited a prominent perivascular tissue. The median L/W and median W/P ratios were 0.54 and 0.48, 0.66 and 0.49, and 0.71 and 0.68, respectively, in GA, GB, and GC. The W/P ratio was significantly higher in GC compared with IFS-exposed animals (P =.001). The difference was significant between GC and GB (P =.008) but not between GC and GA. Conclusion IFS induces coronary perivascular fibrosis that differs under treatment with corticosteroid. Highlights • This study evaluated the morphological changes in rat coronary arteries induced by pure infrasound, created in a laboratory-controlled electroacoustic experiment. • It is the first study assessing the influence of an anti-inflammatory agent on these changes. • The results show that infrasound induces coronary perivascular fibrosis in rats and raise the possibility that an underlying inflammatory mechanism exists. [ABSTRACT FROM AUTHOR]

Since the discovery of graphene in 2004, which proved the existence of 2-D crystals in nature, layered materials also known as van der Waals solids have received extensive reexamination, especially in the single-layer and multilayer forms because of their van der Waals type structure and unique properties that not only benefit many existing electronic components but also enable novel device concepts and design architectures. Numerous research efforts have been invested in these materials, and enormous quantities of results have been generated during the past 14 years. This paper provides an overview of the key physics and technology issues along with the most promising nanoelectronic applications of these materials and also identifies the challenges in this rapidly evolving field. [ABSTRACT FROM AUTHOR]

In0.08Al0.92N/GaN fin-type high-electron mobility transistors (fin-HEMTs) with different gate-to-drain lengths (${L} _{\text {gd}}$) are fabricated and characterized by dc and low-frequency noise (LFN) measurements. The fabricated device with the largest ${L} _{\text {gd}}$ exhibits the degradation of the maximum drain current and transconductance with a positive shift of the threshold voltage. LFN measurements of the In0.08Al0.92N/GaN fin-HEMTs reveal clear 1/ ${f}$ behavior of the noise spectra, and the minimum value is observed in the device at ${L} _{\text {gd}} = {20}\,\,\mu \text{m}$. The devices with smaller ${L} _{\text {gd}}$ follow a carrier number fluctuation noise model owing to electron trapping/detrapping into the In0.08Al0.92N barrier layer from the 2-D electron gas (2DEG) channel. In contrast, the device with the largest ${L} _{\text {gd}}$ shows correlated mobility fluctuations due to the large 2DEG mobility fluctuations in the large access area. [ABSTRACT FROM AUTHOR]

Infrared focal plane arrays imaging system tend to be affected by the interior thermal radiation that drifts slowly over the time, resulting in the continuous spatial low-frequency nonuniformity noise in the image. In this paper, a scene-based nonuniformity correction method for interior thermal radiation is proposed. The gradient domain least mean square (LMS) algorithm is used to estimate the gradient caused by the interior radiation noise according to the fixed spatial low-frequency information in multiframe images. After that, the calibration parameters are obtained by fitting the derivatives of the polynomial-based correction model with the calculated gradient image. The performance of the proposed method is thoroughly studied with infrared image sequences with simulated nonuniformity and real nonuniformity. The results show that the proposed algorithm can remove interior radiation noise more completely without ghosting artifacts than the state-of-art algorithms and is more robust to different scenarios. [ABSTRACT FROM AUTHOR]

It is shown that replacing a TiN effective work function metal by TaN results in a pronounced reduction of the low-frequency noise power spectral density (PSD) of thick-SiO2 input/output (I/O) DRAM peripheral pMOSFETs. The 1/ $f$ noise is originating from carrier number fluctuations, suggesting that the observed reduction results from a decrease of the oxide trap density in the SiO2. On the other hand, I/O pMOSFETs with a TiN gate deposited by different methods or used as a sacrificial gate in a gate replacement integration scheme yield a similar high 1/ $f$ noise PSD and corresponding oxide trap density. [ABSTRACT FROM AUTHOR]

Light field (LF) cameras provide perspective information of scenes by taking directional measurements of the focusing light rays. The raw outputs are usually dark with additive camera noise, which impedes subsequent processing and applications. We propose a novel LF denoising framework based on anisotropic parallax analysis (APA). Two convolutional neural networks are jointly designed for the task: first, the structural parallax synthesis network predicts the parallax details for the entire LF based on a set of anisotropic parallax features. These novel features can efficiently capture the high-frequency perspective components of a LF from noisy observations. Second, the view-dependent detail compensation network restores non-Lambertian variation to each LF view by involving view-specific spatial energies. Extensive experiments show that the proposed APA LF denoiser provides a much better denoising performance than state-of-the-art methods in terms of visual quality and in preservation of parallax details. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the physiological and mental health effects caused by exposure to low-frequency noise in typical control rooms and office-like areas. The participants were 35 male students who were exposed to noise at levels of 55, 65, 70, and 75 dBA. The N-back test was used at three cognitive performance loads (low workload (n = 1), medium workload (n = 2), and high workload (n = 3) to evaluate working memory simultaneously in an air conditioning chamber in four sessions with a constant level. The electroencephalography, electrocardiogram, and electrooculography were measured using Nexus 4 by Bio traces software (Mind Media Co.). For evaluation of mental fatigue, fatigue visual analog scale, and psycho-physiological indices were also used. The results showed that the losses of physiological and mental health were rapidly increased with exposure to noise levels of 65–75 dBA. The results showed that mental fatigue significantly affected heart rate, low- to high-frequency ratios, and electroencephalogram indices such as theta, alpha, as well as eye activities and working memory. The findings confirmed that the mental fatigue caused by low-frequency noise significantly impacted the employees’ psycho-physiological and working memory responses. Implementation of the effective interventions to overcome employees’ mental fatigue in typical control rooms and office-like areas can improve the health and acoustic comfort and, consequently, the cognitive performance. [ABSTRACT FROM AUTHOR]

This paper is about low-frequency noise correlation in current-mode magnetic field transducers. The analysis methodology specifically focuses on the chopper-stabilized MAGFET (CHOPFET), a magnetotransistor that is compatible with the spinning current technique for low-frequency noise and offset cancelation. Experiments performed on a prototype circuit fabricated in the Austria Mikro Systeme 0.35 $\mu \text{m}$ CMOS process show a minimum value of 0.75 noise correlation between the two consecutive switching phases on an arbitrary-chosen terminal and whatever the operation region of the CHOPFET. This includes the contributions of uncorrelated sources, which cannot be separated from the correlated ones in the analysis process. [ABSTRACT FROM AUTHOR]

The temperature-dependent current-voltage ( I-V ) characteristics of permalloy (Ni 0.8 Fe 0.2 ) Schottky contacts to n-type GaN have been investigated. Magnetization measurements revealed the ferromagnetic behavior of Ni 0.8 Fe 0.2 film on n-type GaN. The Schottky barrier parameters, such as the barrier height and ideality factor, determined by thermionic emission depended on the measurement temperature, suggesting the presence of lateral inhomogeneity in the Schottky barrier. The experimental data modified by the thermionic emission model along with a Gaussian distribution of the barrier heights indicated the presence of a double Gaussian barrier distribution in the Ni 0.8 Fe 0.2 /n-type GaN Schottky contact. The mean barrier heights and standard deviations for each Gaussian distribution were 0.84 & 1.32 eV and 0.10 & 0.17 eV over temperature range of 125–200 K and 225–400 K, respectively. The noise spectral density of the current fluctuations measured as a function of frequency ( f ) at room temperature followed a 1/ f γ dependence with a γ value close to unity, irrespective of the applied forward bias. The 1/ f- type noise was attributed to the barrier inhomogeneity existing at the Ni 0.8 Fe 0.2 /n-type GaN Schottky interface as revealed from the temperature-dependent I – V characteristics. [ABSTRACT FROM AUTHOR]

The accuracy of long-term position detection in dual-fiber optical trap is limited by low-frequency noise. We propose a technique that can reduce such noise. A position detection system for dual-fiber optical trap using a quadrant photodiode is built. The transmission light from the trapped particle is detected by two photodiodes. The normalized differential signal of transmission lights is demonstrated to carry the noise caused by asymmetric laser power fluctuation irradiating the microsphere, which is proved to dominate low-frequency noise. By subtracting this normalized difference from the position signal, the noise-reduction capability of this technique is remarkably 67% depending on detection bandwidth. It is expected to be applied to integrated and microfluidic fiber-optic trap system. [ABSTRACT FROM AUTHOR]

Chronic occupational exposure to carbon disulfide (CS2) has debilitating motor and sensory effects in humans, which can increase the risk of falls. Although no mention of vestibulotoxic effects is contained in the literature, epidemiological and experimental data suggest that CS2 could cause low-frequency hearing loss when associated with noise exposure. Low-frequency noise might also perturb the peripheral balance receptor through an as-yet unclear mechanism. Here, we studied how exposure to a low-frequency noise combined with 250-ppm CS2 affected balance in rats. Vestibular function was tested based on post-rotary nystagmus recorded by a video-oculography system. These measurements were completed by behavioral tests and analysis of the cerebellum to measure expression levels for gene expression associated with neurotoxicity. Assays were performed prior to and following a 4-week exposure, and again after a 4-week recovery period. Functional measurements were completed by histological analyses of the peripheral organs.Nystagmus was unaltered by exposure to noise alone, while CS2 alone caused a moderate 19% decrease of the saccade number. In contrast, coexposure to 250-ppm CS2 and low-frequency noise decreased both saccade number and duration by 33% and 34%, respectively. After four weeks, recovery was only partial but measures were not significantly different from pre-exposure values. Real-time quantitative polymerase chain reaction (RT-qPCR) analysis of cerebellar tissue revealed a slight but significant modification in expression levels for two genes linked to neurotoxicity in CS2-exposed animals. However, neither histopathological changes to the peripheral receptor nor behavioral differences were observed. Based on all these results, we propose that the effects of CS2 were due to reversible neurochemical disturbance of the efferent pathways managing post-rotatory nystagmus. Because the nervous structures involving the vestibular function appear particularly sensitive to CS2, post-rotary nystagmus could be used as an early, non-invasive measurement to diagnose CS2 intoxication as part of an occupational conservation program. [ABSTRACT FROM AUTHOR]

It is shown that the free charge carrier capture-emission process causes both the charge carrier density and mobility fluctuations. In this report we present the calculation results in order to find how the capture-emission process affects the free charge carrier mobility and mobility fluctuations. The carrier mobility dependence on phonon, impurity and carrier-carrier scatterings, and the mobility dependence on the electric field and the energy gap variation due to the doping level were taken into account. It is also shown that fluctuations of the charge carrier density and mobility due to the capture-emission process are completely correlated, and that their relaxation times are the same as for the charge capture-emission process. The general expression for estimation of active capture centre density in the volume of a homogeneous sample from the low-frequency noise measurements is presented. [ABSTRACT FROM AUTHOR]

Electrocardiograph (ECG) denoising is the most important step in diagnosis of heart-related diseases, as the diagnosis gets influenced with noises. In this paper, a new method for ECG denoising is proposed, which incorporates empirical mode decomposition algorithm with Riegmann Liouvelle (RL) fractional integral filtering and Savitzky–Golay (SG) filtering. In the proposed method, noisy ECG signal is decomposed into its intrinsic mode functions (IMFs), from which noisy IMFs, corrupted with high-frequency (HF) and low-frequency (LF) noises, are identified by proposed noisy-IMFs identification methodologies. To denoise the signal, RL fractional integral filtering and SG filtering are applied on noisy IMFs corrupted with HF and LF noises, respectively; ECG signal is reconstructed with denoised IMFs and remaining signal dominant IMFs to obtain noise-free ECG signal. Proposed methodology is tested with MIT-BIH arrhythmia database. Its performance, in terms of signal-to-noise ratio and mean square error, is compared with other related ECG denoising methods based on fractional integral, empirical mode decomposition, and ensemble empirical mode decomposition. The obtained results by proposed method prove that the proposed method gives efficient noise removal performance. [ABSTRACT FROM AUTHOR]

We investigated low-frequency noise in two-dimensional (2D) charge density wave (CDW) systems, 1T-TaS2 thin films, as they were driven from the nearly commensurate (NC) to incommensurate (IC) CDW phases by voltage and temperature stimuli. This study revealed that noise in 1T-TaS2 has two pronounced maxima at the bias voltages, which correspond to the onset of CDW sliding and the NC-to-IC phase transition. We observed unusual Lorentzian features and exceptionally strong noise dependence on electric bias and temperature, leading to the conclusion that electronic noise in 2D CDW systems has a unique physical origin different from known fundamental noise types. We argue that noise spectroscopy can serve as a useful tool for understanding electronic transport phenomena in 2D CDW materials characterized by coexistence of different phases and strong pinning. [ABSTRACT FROM AUTHOR]

This study presents an image denoising technique using multiscale non‐local means (NLM) filtering combined with hard thresholding in curvelet domain. The inevitable ringing artefacts in the reconstructed image – due to thresholding – is further processed using a guided image filter for better preservation of local structures like edges, textures and small details. The authors decomposed the image into three different curvelet scales including the approximation and the fine scale. The low‐frequency noise in the approximation sub‐band and the edges with small textural details in the fine scale are processed independently using a multiscale NLM filter. On the other hand, the hard thresholding in the remaining coarser scale is applied to separate the signal and the noise subspace. Experimental results on both greyscale and colour images indicate that the proposed approach is competitive at lower noise strength with respect to peak signal to noise ratio and structural similarity index measure and excels in performance at higher noise strength compared with several state‐of‐the‐art algorithms. [ABSTRACT FROM AUTHOR]

We have evaluated radiation-induced charge trapping and low-frequency noise in passivated black phosphorus (BP) MOSFETs with HfO2 gate dielectrics. Thinning the gate dielectric reduces total ionizing dose-induced threshold voltage shifts. The defect-energy distribution estimated from low-frequency noise measurements performed as a function of temperature decreases with increasing energy in as-processed devices. Local maxima in noise magnitude are observed in irradiated devices at activation energies of ~0.2 and ~0.5 eV. Larger defect-related peaks in noise magnitude in the range of 0.35–0.5 eV are observed after biased post-irradiation annealing, and/or vacuum storage of the devices after irradiation and annealing. Density functional theory calculations strongly support significant roles for O vacancies in HfO2 and H+ transport and reactions near the BP/HfO2 interface in the observed radiation response and low-frequency noise. [ABSTRACT FROM AUTHOR]

We demonstrate technological improvements in phonon sector tests of the Lorentz invariance that implement quartz bulk acoustic wave oscillators. In this experiment, room temperature oscillators with state-of-the-art phase noise are continuously compared on a platform that rotates at a rate of order of a cycle per second. The discussion is focused on improvements in noise measurement techniques, data acquisition, and data processing. Preliminary results of the second generation of such tests are given, and indicate that standard model extension coefficients in the matter sector can be measured at a precision of order 10−16 GeV after taking a year’s worth of data. This is equivalent to an improvement of two orders of magnitude over the prior acoustic phonon sector experiment. [ABSTRACT FROM AUTHOR]