bluuebunny/crossref_metadata_2025 huggingface dataset:
DDX6 modulates P-body and stress granule assembly, composition, and docking
Authors: Ripin Nina , Macedo de Vasconcelos Luisa , Ugay Daniella A. , Parker Roy
Published: March 2024

Stress granules and P-bodies are ribonucleoprotein (RNP) granules that accumulate during the stress response due to the condensation of untranslating mRNPs. Stress granules form in part by intermolecular RNA–RNA interactions and can be limited by components of the RNA chaperone network, which inhibits RNA-driven aggregation. Herein, we demonstrate that the DEAD-box helicase DDX6, a P-body component, can also limit the formation of stress granules, independent of the formation of P-bodies. In an ATPase, RNA-binding dependent manner, DDX6 limits the partitioning of itself and other RNPs into stress granules. When P-bodies are limited, proteins that normally partition between stress granules and P-bodies show increased accumulation within stress granules. Moreover, we show that loss of DDX6, 4E-T, and DCP1A increases P-body docking with stress granules, which depends on CNOT1 and PAT1B. Taken together, these observations identify a new role for DDX6 in limiting stress granules and demonstrate that P-body components can influence stress granule composition and docking with P-bodies.
Pressure-Tuned Intrinsic Anomalous Hall Conductivity in Kagome Magnets RV6Sn6 (R = Gd, Tb)
Authors: Kong 孔 Xiangming 祥明 , Tao 陶 Zicheng 咨成 , Zhang 张 Rui 蕊 , Xia 夏 Wei 威 , Chen 陈 Xu 旭 , Pei 裴 Cuiying 翠颖 , Ying 应 Tianping 天平 , Qi 齐 Yanpeng 彦鹏 , Guo 郭 Yanfeng 艳峰 , Yang 杨 Xiaofan 小帆 , Li 李 Shiyan 世燕
Published: March 2024

Exploration of exotic phenomena in magnetic topological systems is at the frontier of condensed matter physics, holding a significant promise for applications in topological spintronics. However, complex magnetic structures carrying nontrivial topological properties hinder its progresses. Here, we investigate the pressure effect on the novel topological kagome magnets GdV6Sn6 and TbV6Sn6 to dig out the interplay between magnetic Gd/Tb layers and nonmagnetic V-based kagome sublattice. The pressure-tuned magnetic transition temperature T
m in both the compounds exhibit a turning point at the critical pressure P
c, accompanied with a sign reversal in anomalous Hall effect (AHE). The separation of intrinsic and extrinsic contributions using the Tian–Ye–Jin scaling model suggests that the intrinsic mechanism originating from the electronic Berry curvature holds the priority in the competition with extrinsic mechanism in AHE. The above-mentioned findings can be attributed to the combined effect of pressure-tuned band topology and magnetic interaction in segregated layers. Our results provide a practical route to design and manipulate the intrinsic AHE in magnetic topological materials.
The 3d
2
D
5/2−2
D
3/2 magnetic dipole transition in potassium-like ions
Authors: Qian Yuyuan , Zhang Chunyu , Zhang Yizhuo , Chen Jihui , Ding Xiaobin , Huang Liangyu , Yang Yang , Fu Yunqing , Chen Chongyang , Yao Ke
Published: March 2024

Spectral lines of the magnetic-dipole transition between the

3

d
2

D

3

/

2
,

5

/

2

levels of K-like Kr17+, Zr21+, Nb22+, Mo23+, and Ru25+ ions were measured in a compact electron beam ion trap. By means of dedicated calibration methods, the transition wavelengths of Kr17+, Zr21+, and Mo23+ ions reduce uncertainties by at least one order of magnitude and the wavelengths of Nb22+ and Ru25+ ions are measured for the first time at a few ppm level. In addition, the fine-structure energy splittings were systematically calculated using the multiconfiguration Dirac–Hartree–Fock method combined with the relativistic configuration interaction approach. The contributions of the core-valence and core-core electron correlations, the Breit interaction and QED effect were discussed in detail. The results show that it is essential to include deep core-valence correlation of L-shell and core-core valence correlation of 3p subshell to obtain an agreement better than 0.15% with existing experimental values. The calculation model can be performed to predict the wavelength within a high accuracy for a wide range of potassium-like ions.
Polyaniline-graphene based composites electrode materials in supercapacitor: synthesis, performance and prospects
Authors: Guo Zefei , Liu Gengzheng , Hao Huilian , Yang Jun , Lei Huayu , Shi Xuerong , Li Wenyao , Liu Wenfu
Published: March 2024

Supercapacitors (SCs) have become one of the most popular energy-storage devices for high power density and fast charging/discharging capability. Polyaniline is a class of conductive polymer materials with ultra-high specific capacitance, and the excellent mechanical properties will play a key role in the research of flexible SCs. The synergistic effect between polyaniline and graphene is often used to overcome their respective inherent shortcomings, thus the high-performance polyaniline-graphene based nanocomposite electrode materials can be prepared. The development of graphene-polyaniline nanocomposites as electrode materials for SCs depends on their excellent microstructure design. However, it is still difficult to seek a balance between graphene performance and functionalization to improve the weak interfacial interaction between graphene and polyaniline. In this manuscript, the latest preparation methods, research progress and research results of graphene-polyaniline nanocomposites on SCs are reviewed, and the optimization of electrode structures and performances is discussed. Finally, the prospect of graphene-polyaniline composites is expected.
The influence of charge ordering in the microscopic structure of monohydroxy alcohols
Authors: Požar Martina , Lovrinčević Bernarda , Perera Aurélien
Published: March 2024

While radiation scattering data provides insight inside the microstructure of liquids, the Debye relation relating the scattering intensity I(k) to the atom–atom structure factors

S

a
b

(
k
)

shows that, ultimately, it is these individual structure correlation functions which contain the relevant information about the micro-structure. However, these quantities are not observables, except in few cases where one can invert the Debye relation to obtain the structure functions. In the majority of other cases, the need for model dependent computer simulations is unavoidable. The resulting calculations reveal that the scattering pre-peak is the result of cancellations between positive pre-peaks and negative anti-peaks contributions from the atom–atom structure factors. What of systems where this cancellation is such that it entirely suppresses the scattering pre-peak? One would be tempted to falsely conclude that there is no underlying micro-heterogeneity. Hence, the structure functions appear as hidden variables, and it is important to understand the relation between their features and the micro-structure of the system. Through the computer simulation study of various mono-ols, ranging from methanol to 1-nonanol, as well as the branched octanols, we show how the features of the atom–atom pair correlation function

g

a
b

(
r
)

affect that of the structure factors

S

a
b

(
k
)

, and reveal that the micro-structure is ultimately the result of the charge ordering between different atoms in the system.
Guiding infrared electromagnetic waves through TI nanowires with extremely large wavenumber and azimuthal index
Authors: Li Y W , Chen M N , Dai J Y , Zhou Yu
Published: March 2024

In this paper, the dispersion relations of the surface plasmon polaritons (SPPs) in TI nanowires have been investigated. For simplicity, TI nanowire has been modeled as a dielectric cylinder with a conductive surface, the conductivity of which is an anti-symmetric tensor. The off-diagonal terms of the conductivity tensor only slightly change the dispersion relations. Due to small conductivities, these SPPs have extremely large wavenumbers and azimuthal indices; the electric fields are tightly confined near the conductive surface. For high-order modes, cut-off phenomena have been observed. In the end, the effects of losses and much larger bulk permittivities on the dispersion relations of surface plasmons have been discussed. The simple model proposed in this paper can be directly applied to other materials with arbitrary surface conductivity. Our investigations show that TI nanostructures are promising platforms for nanophotonic applications in the future.
Enhanced weak superconductivity in trigonal γ-PtBi2
Authors: Zabala J , Correa V F , Castro F J , Pedrazzini P
Published: March 2024

Electrical resistivity experiments show superconductivity at

T
c

=
1.1

K in a high-quality single crystal of trigonal γ-PtBi2, with an enhanced critical magnetic field

μ
0

H

c
2

(
0
)
≳
1.5

Tesla and a low critical current-density

J
c

(
0
)
≈
40

 A cm−2 at H = 0. Both Tc
and

H

c
2

(
0
)

are the highest reported values for stoichiometric bulk samples at ambient pressure. We found a weak

H

c
2

anisotropy with

Γ
=

H

c
2

a
b

/

H

c
2

c

<
1

, which is unusual among superconductors. Under a magnetic field, the superconducting transition becomes broader and asymmetric. Along with the low critical currents, this observation suggests an inhomogeneous superconducting state. In fact, no trace of superconductivity is observed through field-cooling–zero-field-cooling magnetization experiments.
Robust room temperature perpendicular magnetic anisotropy and anomalous Hall effect of sputtered NiCo2O4 film
Authors: Zheng Biao , Ji Xianghao , Xue Mingzhu , Jia Caihong , Kang Chaoyang , Zhang Weifeng , Yang Jinbo , Tian Mingliang , Chen Xuegang
Published: March 2024

Inverse spinel ferrimagnetic NiCo2O4 (NCO) exhibits volatile physical properties due to the complex ion/valence occupation, which complicates the study its intrinsic properties. In this work, robust room temperature perpendicular magnetic anisotropy (PMA) is distinctly observed in high-quality RF-sputtered NCO film down to 3 uc (2.4 nm), confirmed by the room temperature anomalous Hall effect. The NCO films show a good metallic conductivity with a dimensional driven metal-insulator transition. The scaling relation between anomalous Hall conductivity (

σ

x
y

) and the longitudinal conductivity (

σ

x
x

) reveals the dirty metal behavior in conjunction with the contribution of intrinsic Berry phase or disorder-enhanced electron correlation contribute to the anomalous Hall effect for thick films while the dirty scaling law dominates for the thin films. This work introduces an oxide candidate with robust room temperature PMA as well as massive production ability for the functional spintronic applications.
Radiation levels outside a patient undergoing 177Lu-PSMA radioligand therapy
Authors: Li Huan , Liu Haikuan , Zhang Weiyuan , Lin Xin , Li Zhiling , Zhuo Weihai
Published: March 2024

Understanding the spatial distribution of radiation levels outside of a patient undergoing 177Lu radioligand therapy is not only helpful for conducting correct tests for patient release, but also useful for estimation of its potential exposure to healthcare workers, caregivers, family members, and the general public. In this study, by mimicking the 177Lu-labeled prostate-specific membrane antigen radioligand therapy for prostate cancers in an adult male, the spatial distribution of radiation levels outside of the phantom was simulated based on the Monte Carlo software of Particle and Heavy Ion Transport System, and verified by a series of measurements. Moreover, the normalized dose rates were further formulized on the three transverse planes representing the heights of pelvis, abdomen and chest. The results showed that the distributions of radiation levels were quite complex. Multi-directional and multi-height measurements are needed to ensure the external dose rate to meet the release criteria. In general, the radiation level was higher at the horizontal plane where the source was located, and the levels in front and behind of the body were higher than those of the left and right sides at the same height. The ratio of simulated dose rates to measured ones ranged from 0.82 to 1.19 within 1 m away from the body surface in all directions. Based on the established functions, the relative root mean square deviation between the calculated and simulated values were 0.21, 0.25 and 0.23 within a radius of 1 m on the pelvis, abdomen and chest transverse planes, respectively. It is expected that the results of this study would be helpful for guiding the test of extracorporeal radiation to determine the patient’s release, and of benefit to estimate the radiation exposure to others.
Towards the establishment of national diagnostic reference levels for abdomen, KUB, and lumbar spine x-ray examinations in Sri Lanka: a multi-centric study
Authors: Welarathna Sachith , Velautham Sivakumar , Sarasanandarajah Sivananthan
Published: March 2024

Diagnostic reference levels (DRLs) and achievable doses (ADs) provide guidance to optimise radiation doses for patients undergoing medical imaging procedures. This multi-centre study aimed to compare institutional DRLs (IDRLs) across hospitals, propose ADs and multi-centric DRLs (MCDRLs) for four common x-ray examinations in Sri Lanka, and assess the potential for dose reduction. A prospective cross-sectional study of 894 adult patients referred for abdomen anteroposterior (AP), kidney-ureter-bladder (KUB) AP, lumbar spine AP, and lumbar spine lateral (LAT) x-ray examinations was conducted. Patient demographic information (age, sex, weight, BMI) and exposure parameters (tube voltage, tube current-exposure time product) were collected. Patient dose indicators were measured in terms of kerma-area product (PKA) using a PKA meter. IDRLs, ADs, and MCDRLs were calculated following the International Commission on Radiological Protection guidelines, with ADs and MCDRLs defined as the 50th and 75th percentiles of the median PKA distributions, respectively. IDRL ranges varied considerably across hospitals: 1.42–2.42 Gy cm2 for abdomen AP, 1.51–2.86 Gy cm2 for KUB AP, 0.83–1.65 Gy cm2 for lumbar spine AP, and 1.76–4.10 Gy cm2 for lumbar spine LAT. The proposed ADs were 1.82 Gy cm2 (abdomen AP), 2.03 Gy cm2 (KUB AP), 1.27 Gy cm2 (lumbar spine AP), and 2.21 Gy cm2 (lumbar spine LAT). MCDRLs were 2.24 Gy cm2 (abdomen AP), 2.40 Gy cm2 (KUB AP), 1.43 Gy cm2 (lumbar spine AP), and 2.38 Gy cm2 (lumbar spine LAT). Substantial intra- and inter-hospital variations in PKA were observed for all four examinations. Although ADs and MCDRLs in Sri Lanka were comparable to those in the existing literature, the identified intra- and inter-hospital variations underscore the need for dose reduction without compromising diagnostic information. Hospitals with high IDRLs are recommended to review and optimise their practices. These MCDRLs serve as preliminary national DRLs, guiding dose optimisation efforts by medical professionals and policymakers.
The pioneer of intelligent and sustainable construction in tunnel shotcrete applications: a comprehensive experimental and numerical study on a self-sensing and self-heating green cement-based composite
Authors: Abedi Mohammadmahdi , Gulisano Federico , Han Baoguo , Fangueiro Raul , Correia António Gomes
Published: March 2024

In this study, a self-sensing and self-heating natural fibre-reinforced cementitious composite for the shotcrete technique was developed using Kenaf fibres. For this purpose, a series of Kenaf fibre concentrations were subjected to initial chemical treatment, followed by integration into the cement-based composite containing hybrid carbon nanotubes (CNT) and graphene nanoplatelets (GNP). The investigation encompassed an examination of mechanical, microstructural, sensing, and joule heating performances of the environmentally friendly shotcrete mixture, with subsequent comparisons drawn against a counterpart blend featuring a conventionally synthesized polypropylene (PP) fibre. Following the experimental phase, a comprehensive 3D nonlinear finite difference (3D NLFD) model of an urban twin road tunnel, completed with all relevant components, was meticulously formulated using the FLAC3D (fast lagrangian analysis of continua in 3 dimensions) code. This model was subjected to rigorous validation procedures. The performances of this green shotcrete mixture as the lining of the inner shell of the tunnel were assessed comparatively using this 3D numerical model under static and dynamic loading. The twin tunnel was subjected to a harmonic seismic load as a dynamic load with a duration of 15 s. The laboratory findings showed a reduction in the composite sensing and heating potentials in both cases of Kenaf and PP fibre reinforcement. Incorporating a specific quantity of fibre yields a substantial enhancement in both the mechanical characteristics and microstructural attributes of the composite. An analysis of digital image correlation demonstrated that Kenaf fibres were highly effective in controlling cracks in cement-based composites. Furthermore, based on the static and dynamic 3DNLFD analysis, this green cement-based composite demonstrated its potential for shotcrete applications as the lining of the inner shell of the tunnel. This study opens an appropriate perspective on the extensive and competent contribution of natural fibres for multifunctional sustainable, reliable and affordable cement-based composite developments for today’s world.
Photon correlations in the collective emission of hybrid gold-(CdSe/CdS/CdZnS) nanocrystal supraparticles
Authors: Blondot V , Gérard D , Quibeuf G , Arnold C , Delteil A , Bogicevic A , Pons T , Lequeux N , Buil S , Hermier J-P
Published: March 2024

We investigate the photon statistics of the light emitted by single self-assembled hybrid gold-CdSe/CdS/CdZnS colloidal nanocrystal supraparticles through the detailed analysis of the intensity autocorrelation function g
(2)(τ). We first reveal that, despite the large number of nanocrystals involved in the supraparticle emission, antibunching can be observed. We then present a model based on non-coherent Förster energy transfer and Auger recombination that well captures photon antibunching. Finally, we demonstrate that some supraparticles exhibit a bunching effect at short time scales corresponding to coherent collective emission.
The impact of motion on onboard MRI-guided pencil beam scanned proton therapy treatments
Authors: Duetschler Alisha , Safai Sairos , Weber Damien C , Lomax Antony J , Zhang Ye
Published: March 2024

Objective. Online magnetic resonance imaging (MRI) guidance could be especially beneficial for pencil beam scanned (PBS) proton therapy of tumours affected by respiratory motion. For the first time to our knowledge, we investigate the dosimetric impact of respiratory motion on MRI-guided proton therapy compared to the scenario without magnetic field. Approach. A previously developed analytical proton dose calculation algorithm accounting for perpendicular magnetic fields was extended to enable 4D dose calculations. For two geometrical phantoms and three liver and two lung patient cases, static treatment plans were optimised with and without magnetic field (0, 0.5 and 1.5 T). Furthermore, plans were optimised using gantry angle corrections (0.5 T +5° and 1.5 T +15°) to reproduce similar beam trajectories compared to the 0 T reference plans. The effect of motion was then considered using 4D dose calculations without any motion mitigation and simulating 8-times volumetric rescanning, with motion for the patient cases provided by 4DCT(MRI) data sets. Each 4D dose calculation was performed for different starting phases and the CTV dose coverage V
95% and homogeneity D
5%–D
95% were analysed. Main results. For the geometrical phantoms with rigid motion perpendicular to the beam and parallel to the magnetic field, a comparable dosimetric effect was observed independent of the magnetic field. Also for the five 4DCT(MRI) cases, the influence of motion was comparable for all magnetic field strengths with and without gantry angle correction. On average, the motion-induced decrease in CTV V
95% from the static plan was 17.0% and 18.9% for 1.5 T and 0.5 T, respectively, and 19.9% without magnetic field. Significance. For the first time, this study investigates the combined impact of magnetic fields and respiratory motion on MR-guided proton therapy. The comparable dosimetric effects irrespective of magnetic field strength indicate that the effects of motion for future MR-guided proton therapy may not be worse than for conventional PBS proton therapy.
SAPPHIRE —establishment of small animal proton and photon image-guided radiation experiments
Authors: Schneider Moritz , Schilz Joshua D , Schürer Michael , Gantz Sebastian , Dreyer Anne , Rothe Gert , Tillner Falk , Bodenstein Elisabeth , Horst Felix , Beyreuther Elke
Published: March 2024

The in vivo evolution of radiotherapy necessitates innovative platforms for preclinical investigation, bridging the gap between bench research and clinical applications. Understanding the nuances of radiation response, specifically tailored to proton and photon therapies, is critical for optimizing treatment outcomes. Within this context, preclinical in vivo experimental setups incorporating image guidance for both photon and proton therapies are pivotal, enabling the translation of findings from small animal models to clinical settings. The SAPPHIRE project represents a milestone in this pursuit, presenting the installation of the small animal radiation therapy integrated beamline (SmART+ IB, Precision X-Ray Inc., Madison, Connecticut, USA) designed for preclinical image-guided proton and photon therapy experiments at University Proton Therapy Dresden. Through Monte Carlo simulations, low-dose on-site cone beam computed tomography imaging and quality assurance alignment protocols, the project ensures the safe and precise application of radiation, crucial for replicating clinical scenarios in small animal models. The creation of Hounsfield lookup tables and comprehensive proton and photon beam characterizations within this system enable accurate dose calculations, allowing for targeted and controlled comparison experiments. By integrating these capabilities, SAPPHIRE bridges preclinical investigations and potential clinical applications, offering a platform for translational radiobiology research and cancer therapy advancements.
Three-row MRI receive array with remote circuitry to preserve radiation transparency
Authors: Lakshmanan Karthik , Wang Bili , Walczyk Jerzy , Collins Christopher M , Brown Ryan
Published: March 2024

Objective. Up to this point, 1.5 T linac-compatible coil array layouts have been restricted to one or two rows of coils because of the desire to place radiation-opaque circuitry adjacent to the coils and outside the window through which the linac beam travels. Such layouts can limit parallel imaging performance. The purpose of this work was to design and build a three-row array in which remotely located circuits permitted a central row of coils while preserving the radiolucent window. Approach. The remote circuits consisted of a phase shifter to cancel the phase introduced by the coaxial link between the circuit and coil, followed by standard components for tuning, matching, detuning, and preamplifier decoupling. Tests were performed to compare prototype single-channel coils with remote or local circuits, which were followed by tests comparing two and three-row arrays . Main results. The single-channel coil with the remote circuit maintained 85% SNR at depths of 30 mm or more as compared to a coil with local circuit. The three-row array provided similar SNR as the two-row array, along with geometry factor advantages for parallel imaging acceleration in the head–foot direction. Significance. The remote circuit strategy could potentially support future MR-linac arrays by allowing greater flexibility in array layout compared to those confined by local circuits, which can be leveraged for parallel imaging acceleration.
Spatio-temporal analysis of power deposition and vibrational excitation in pulsed N2 microwave discharges from 1D fluid modelling and experiments
Authors: Altin M , Viegas P , Vialetto L , van Rooij G J , Diomede P
Published: March 2024

Vibrational excitation of N2 beyond thermodynamic equilibrium enhances the reactivity of this molecule and the production of radicals. Experimentally measured temporal and spatial profiles of gas and vibrational temperature show that strong vibrational non-equilibrium is found in a pulsed microwave discharges at moderate pressure (25 mbar) in pure N2 outside the plasma core and as an effect of power pulsing. A one dimensional radial time-resolved self-consistent fluid model has been developed to study the mechanism of formation of vibrationally excited N2. In addition to the temperature maps, time-resolved measurements of spontaneous optical emission, electron density and electron temperature are used to validate the model and the choice of input power density. The model reveals two regions in the plasma: a core where chemistry is dominated by power deposition and where vibrational excitation starts within the first ∼10 µs and an outer region reliant on radial transport, where vibrational excitation is activated slowly during the whole length of the pulse (200 µs). The two regions are separated by a sharp gradient in the estimated deposited power density, which is revealed to be wider than the emission intensity profile used to estimate the plasma size. The low concentration of excited species outside the core prevents the gas from heating and the reduced quenching rates prevent the destruction of vibrationally excited N2, thereby maintaining the observed high non-equilibrium.
Electrical characteristics of the GEC reference cell at low pressure: a two-dimensional PIC/MCC modeling study
Authors: Chen Zili , Wang Hongyu , Yu Shimin , Wang Yu , Chen Zhipeng , Jiang Wei , Schulze Julian , Zhang Ya
Published: March 2024

The electrical characteristics of the Gaseous Electronics Conference reference cell at low pressures are investigated using a two-dimensional electrostatic implicit particle-in-cell/Monte Carlo collision model in cylindrical coordinates. The coupling between the complex reactor geometry and the external circuit is included via an equivalent capacitance calculated from the electric energy density and the charge conservation equation. The results of this model are compared with experimental measurements and other model calculations and show agreement. The plasma series resonance effect, closely related to electron heating, is observed in this numerical simulation of a strongly asymmetric reactor at low pressures. The plasma kinetics of the capacitively coupled discharge and details of the external circuit response, including electrical waveforms and higher-order harmonics, are discussed at different pressures, which provides important insights for understanding the power coupling mechanisms in capacitively coupled discharges.
A novel MOSFET with lateral–vertical charge coupling for extremely low C
gd
Authors: Wang Tongyang , Li Zehong , Li Luping , Yang Yang , Zhao Yishang , Xia Ziming , Zheng Yige , Ye Jun , Xiao Xuan
Published: March 2024

A novel MOSFET with lateral–vertical charge coupling (LVCC-MOSFET) is proposed in this paper. Lateral charge coupling is enabled by a metal field plate, lightly doped drain and P-Epi layer to reduce the C
gd. Vertical charge coupling is enabled by a shield gate, sinker and P-Epi layer to support a high breakdown voltage (BV) and further reduce the C
gd. By combining both lateral charge coupling and vertical charge coupling, which is first proposed in low-voltage power MOSFETs, the trade-off relationship between BV, R
on and C
gd can be significantly improved. It is verified by both small-signal analysis and transient capacitance simulation that the gate-to-drain capacitance of the proposed LVCC-MOSFET can be reduced by more than 99% without deterioration of BV and R
on. The LVCC-MOSFET achieves 93.7% reduction in Q
gd, and R
on × Q
gd is only 0.81 mΩ·nC, which is reduced by 93.9%. Furthermore, E
on and E
off can be reduced by 73.6% and 53.8%, respectively. The hot carrier injection reliability can be enhanced by reducing the electric field and the impact ionization generation rate near the drain-side gate oxide. Moreover, the LVCC-MOSFET can be feasibly manufactured with compatible fabrication process flow, and only three extra steps are needed.
Dual-band filtering and enhanced directional via tunable acoustic metamaterial antennas
Authors: Xiao Jiawei , Ding Xiaoxi , Pan Huafei , Zhang Ying , He Qingbo , Shao Yimin
Published: March 2024

The detection of acoustic signals in strong background noise plays a crucial role in industrial non-destructive, mechanical equipment health monitoring and acoustic communication. The major bottleneck of this technology lies in the limited high-sensitivity and high-directivity of acoustic sensors. Here, this study proposes a tunable acoustic metamaterial antenna (TAMAA) with a double bandgap and near-zero refractive index. Different from the traditional geometric scatterer, a gear-shaped structure is introduced to enhance the controllability of the acoustic system. We theoretically demonstrate the physical properties of the structure with a double bandgap and near-zero refractive index. Remarkably, the gear-shaped honeycomb lattice structure exhibits an adjustable bandgap region, which enables the multiplexing of both acoustic shielding and acoustic enhancement functions by controlling the rotation angle of the scatterer. Furthermore, through numerical computational and experimental studies, we demonstrate that the proposed TAMAA exhibits dual-band filtering capabilities and provides excellent acoustic directional enhancement. Moreover, it allows for the recovery of weak acoustic signals even in the presence of extremely low signal-to-noise ratio and strong spatial noise interference. This work breaks through the detection limits of conventional acoustic sensing systems and provides new ideas for the development of acoustic sensing detection.
A novel adjustable magnetorheological fluid gradient material of low frequency vibration isolation: a theoretical and experimental study
Authors: Sun Zebang , Zhao Dan , Dong Liqiang , Qi Jinming , Guo Chang , Liu Shaogang
Published: March 2024

In this paper, a novel adjustable magnetorheological fluid (MRF) gradient material for low-frequency control is proposed, and the vibration isolation performance of this gradient material is investigated theoretically and experimentally. The gradient material has an excellent ability to control the sound waves and vibrations. However, the currently prepared gradient material does not have the parameter adjustability. At the same time, the MRF can change its material parameters according to the external magnetic field. After applying the traveling magnetic field (TMF) to the MRF with continuously varying and adjustable magnetic induction strength, its material parameters will also be continuously varying and adjustable to constitute an adjustable gradient material. In order to investigate the vibration transfer characteristics of this adjustable gradient material, this paper establishes a micro-mechanical model of MRF and theoretically investigates and numerically calculates the mechanical impedance and vibration transfer characteristics of the adjustable gradient material through the machine-electric analogy theory. At the same time, experimental research was conducted by building an experimental platform to conduct experiments. The results show that the novel adjustable gradient material composed of a TMF and MRF has a good vibration suppression effect in the low-frequency range (10 ∼ 60 Hz) with the vibration level difference of up to 30 dB or more, which has a broad application prospect in the field of vibration control.
Design and analysis of an extended buckled beam piezoelectric energy harvester subjected to different axial preload
Authors: Sun Wen-Po , Su Wei-Jiun
Published: March 2024

In this paper, a piezoelectric energy harvester composed of a buckled beam and an extended beam with a tip mass is proposed. This study develops a mathematical model and a prototype of the energy harvester. The performance of the energy harvester is influenced by the axial load applied at the end of the buckled beam. Under an axial force below the critical load, the energy harvester exhibits a pre-buckling state with a hardening nonlinear characteristic. Conversely, when the axial force exceeds the critical load, a post-buckling state with a softening nonlinear characteristic is observed. Simulation results are validated through experiments, and the relationship between axial displacement and axial force is obtained through experimental data. Moreover, increasing the tip mass enhances the output voltage under the same acceleration. The energy harvester demonstrates superior performance in terms of output power and strain distribution compared to a cantilever counterpart.
An invertible hysteresis model for magnetorheological damper with improved adaption capability in frequency and amplitude
Authors: Xing Xudong , Chen Zhaobo , Yu Dong , Feng Zhongqiang , Liu Yuechen
Published: March 2024

It is found during the tests that the damping characteristics of the magnetorheological (MR) damper vary with the excitation amplitude and frequency. However, the existing MR damper models are not able to accommodate the change of excitation amplitude and frequency, which will lead to significant modeling errors. To deal with this problem, this paper analyzes the experimental data and obtains the regularity of the damping characteristics varying with the excitation. Subsequently, an excitation-adaptive MR damper model is constructed based on the hyperbolic tangent function. The proposed model is not only able to adapt to the change of excitation amplitude and frequency but also able to inverse, which is essential for MR damper controller construction. The fitting results show that compared with the existing models, the three normalized errors of the proposed model are improved from 22.61%, 13.96%, and 19.42%–6.30%, 3.81%, and 6.97%, respectively, indicating that the model excitation adaptivity is significantly improved. Furthermore, this study also proposed a damper controller based on the new model, and the simulation results verify the effectiveness of the controller. The proposed model brings the acceleration signal into the model to improve the model adaptivity, which introduces a novel approach to enhance the adaptivity of MR damper models.
Experimental bounds on linear-friction dissipative collapse models from levitated optomechanics
Authors: Di Bartolomeo Giovanni , Carlesso Matteo
Published: March 2024

Collapse models constitute an alternative to quantum mechanics that solve the well-know quantum measurement problem. In this framework, a novel approach to include dissipation in collapse models has been recently proposed, and awaits experimental scrutiny. Our work establishes experimental bounds on the so-constructed linear-friction dissipative Diósi-Penrose (dDP) and Continuous Spontaneous localisation (dCSL) models by exploiting experiments in the field of levitated optomechanics. Our results in the dDP case exclude collapse temperatures below 10−13 K and

6
×

10

−
12

 K respectively for values of the localisation length smaller than 10−6 m and 10−8 m. In the dCSL case the entire parameter space is excluded for values of the temperature lower than

6
×

10

−
9

 K.
Exploring the synergistic potential of mixed metal sulfides in hybrid supercapacitors
Authors: Iqbal Muhammad Zahir , Abbasi Usman , Khizar Asma , Wabaidur Saikh Mohammad , Alam Shahid , Iqbal Muhammad Javaid , Faisal Mian Muhammad
Published: March 2024

In energy reservoirs, hybrid supercapacitors (HSCs) have gained incredible recognition owing to their exceptional specific energy (Es), Specific power (Ps), and high cyclic stability. However, electroactive electrode materials with flashing electrochemical features and high storage ability are still required. In this regard, nickel-cobalt binary sulfide composites need further exploration as an electrode material owing to their high electrochemical properties, better conductivity, excellent redox reversibility, and high-rate capability. Here, we account the electrochemical activities and synthesis of composites including (nickel and cobalt sulfides). The composites were analyzed for structural and morphological analysis using XRD and SEM techniques, respectively. Amidst all other compositions, Ni0.75Co0.25S exhibited the optimum electrochemical performance measured in half-cell assembly with specific capacity (Qs) of 1147.6 Cg−1 and 900 Cg−1 at lowest scan rate and current density respectively. This electroactive electrode material together with activated carbon (AC) was further utilized in two cell assembly. This Hybrid device revealed ES of 50.21 Whkg−1 and Ps of 9350 Wkg−1 with capacity retention of 80.30% after consecutive charge discharge. The performance analysis of the actual device was further examined using a simulation approach, focusing on both capacitive and diffusive contributions by comparing the results of both linear and quadratic models. These attractive results revealed by Ni0.75Co0.25S signify it as favorable electrode material for hybrid supercapacitor applications.
Ion implantation induced p-type conductivity in FeS2 thin film
Authors: Chakraborty Rudra Narayan , Mahanta Dipta Suryya , Mazumder Santu , Senthilkumar Kasilingam
Published: March 2024

In pursuing sustainable energy solutions, thin-film solar cells based on the Copper zinc tin sulfide (CZTS) absorber material have garnered significant attention due to their earth-abundant and non-toxic composition. However, the modest efficiency demonstrated by CZTS solar cells has prompted researchers to investigate novel approaches to improve their performance. An area of potential advancement entails the integration of appropriate hole transport layers (HTLs). In this simulation-based study, we focused on FeS2 as a highly promising candidate for use as an HTL in CZTS-based solar cells. FeS2, traditionally considered n-type, was tailored to achieve p-type conductivity through the negative ion implantation (O, P, and As) process. 40 keV ion beam was utilized, with three doses (105, 1010, 1015 cm−2) applied for each ion beam. We demonstrate successful p-type doping of FeS2 with a hole concentration of ∼1020 cm−3 in case of 1015 cm−2 dose, paving the way for its integration as an effective HTL within the CZTS solar cell structure.
Edge-dependent electronic transport and diode effect in C3N nanoribbons
Authors: Berdiyorov G R
Published: March 2024

Quantum transport calculations are conducted for C3N nanoribbons with different edge terminations within the nonequilibrium Green’s function formalism in combination with density functional theory. The electronic transport in the system strongly depends on the properties of the edge states. For example, the current in metallic carbon-terminated nanoribbons is several orders of magnitude higher than the current in nitrogen-terminated nanoribbons with a semiconducting nature. In addition, C-terminated nanoribbons show very pronounced negative differential resistance. A diode structure with a rectification ratio of 10 is proposed, consisting of a heterojunction of C- and N-terminated nanoribbons. These findings can be of practical importance in creating functional device structures from this 2D material.
Synthesis of PANI@Ce-doped ZnO (PCZ) heterojunction: A UV-Driven photocatalyst for reduction of methylene blue and study of their structural, optical and electrical properties
Authors: Dhanda Ekta , Nain Aditi , Dahiya Sanjay
Published: March 2024

To address the significant issue of wastewater treatment, this research focused on synthesizing PANI@Ce-doped ZnO (PCZ) nanocomposites, a heterojunction with varying dopant concentrations. This heterojunction was prepared using an ultrasonic-assisted wet impregnation technique and underwent comprehensive analysis through several techniques, including XRD, UV-DRS, Photoluminescence, FE-SEM, EDAX, and Impedance Analyzer. The XRD study was done to analyse the crystalline nature of as synthesized nanocomposites, while FESEM with EDX confirm the nanoflower morphology and presence of each element respectively. The optical band gap energy (Eg) of the samples has been estimated using UV-DRS and is found in the visible region. The synergy between the organic and inorganic frameworks resulted in an additive effect on the photocatalyst’s degradation efficiency. In the photocatalytic degradation process, reactive oxygen species (ROSs), including O2, OH, and h+, played a crucial role in breaking down MB (Methylene Blue) using the PANI@Ce-doped ZnO nanocomposites. PCZ1 exhibited significantly elevated dye degradation efficiency (86.80%) in comparison to bare PANI (40.80%). This enhancement can be attributed to the improved transfer and separation of photogenerated charge carriers in prepared heterojunction.
Quasi-three-level laser pumped Yb:GdCOB tunable laser from 1030 to 1036 nm
Authors: Wang Jiarui , Zhang Yaoyu , Li Yongliang
Published: March 2024

We report a quasi-three-level laser pumped Ca4GdO(BO3)3 (Yb:GdCOB) tunable laser based on the transition from the 2
F
5/2 level to the 2
F
7/2 level. By adjusting the 902 nm pump power, a continuous waves Yb:GdCOB laser was obtained with the near-infrared wavelengths shifting from 1030 nm to 1036 nm. The highest tuning power of 2.5 W was achieved with a slope efficiency of 19.9%. To our knowledge, it is the first tunable Yb:GdCOB laser to be realized by adjusting the pump power. This work provides a novel method to generate tunable solid-state lasers with a compact and simple structure.
Quasi-classical theory of cyclotron resonance with accounting for dissipation
Authors: Sazonov S V
Published: March 2024

Based on the quasi-classical version of the canonical Caldirola–Kanai quantization, non-relativistic cyclotron resonance in a dissipative medium is studied. The corresponding particle propagator in the coordinate representation is found. It is shown that the combined effect of dissipation and a constant magnetic field reduces to the suppression of the quantum properties of a charged particle. In turn, a time-varying electric field that causes cyclotron resonance does not exhibit similar properties and does not affect the uncertainties of the particle coordinates.
Activation and depression of neural and hemodynamic responses induced by the intracortical microstimulation and visual stimulation in the mouse visual cortex
Authors: Suematsu Naofumi , Vazquez Alberto L , Kozai Takashi D Y
Published: March 2024

Objective. Intracortical microstimulation (ICMS) can be an effective method for restoring sensory perception in contemporary brain–machine interfaces. However, the mechanisms underlying better control of neuronal responses remain poorly understood, as well as the relationship between neuronal activity and other concomitant phenomena occurring around the stimulation site. Approach. Different microstimulation frequencies were investigated in vivo on Thy1-GCaMP6s mice using widefield and two-photon imaging to evaluate the evoked excitatory neural responses across multiple spatial scales as well as the induced hemodynamic responses. Specifically, we quantified stimulation-induced neuronal activation and depression in the mouse visual cortex and measured hemodynamic oxyhemoglobin and deoxyhemoglobin signals using mesoscopic-scale widefield imaging. Main results. Our calcium imaging findings revealed a preference for lower-frequency stimulation in driving stronger neuronal activation. A depressive response following the neural activation preferred a slightly higher frequency stimulation compared to the activation. Hemodynamic signals exhibited a comparable spatial spread to neural calcium signals. Oxyhemoglobin concentration around the stimulation site remained elevated during the post-activation (depression) period. Somatic and neuropil calcium responses measured by two-photon microscopy showed similar dependence on stimulation parameters, although the magnitudes measured in soma was greater than in neuropil. Furthermore, higher-frequency stimulation induced a more pronounced activation in soma compared to neuropil, while depression was predominantly induced in soma irrespective of stimulation frequencies. Significance. These results suggest that the mechanism underlying depression differs from activation, requiring ample oxygen supply, and affecting neurons. Our findings provide a novel understanding of evoked excitatory neuronal activity induced by ICMS and offer insights into neuro-devices that utilize both activation and depression phenomena to achieve desired neural responses.
Correlation of source parameters and beam properties in the early operation of the full size ITER negative ion beam source
Authors: Ugoletti M. , Agostini M. , Poggi C. , Sartori E. , Serianni G. , Zaniol B.
Published: March 2024

One of the requirements of Heating and current drive Neutral Beam injectors for ITER is a beam homogeneity greater than 90%, to achieve an optimal beam transmission while keeping the heat load consistently low on the acceleration electrodes. The large size and complexity of ITER negative ion source play a key role in determining the homogeneity of the negative ion current of each of the 1280 beamlets and their divergence, and it is studied in the full-scale prototype source SPIDER. In this work the plasma properties are studied by spectroscopic and electrostatic measurements in the drivers, where the plasma is generated, and in the expansion region, where the plasma drifts and negative ions are produced, and they are correlated with the properties of the beam. The non-homogeneous plasma density profile is related to the non-homogeneous availability of negative ions along the beam vertical profile, with and without cesium evaporation. Visible tomography, a technique capable of characterizing isolated beamlet properties, is used to study the beam’s dependence on plasma uniformity along the entire beam profile. Using these tools, it has been demonstrated how an increase in plasma density is linked to an improvement in beam homogeneity. The latter has been directly correlated with plasma homogeneity. The magnetic filter field and biases of the plasma grid and bias plate are responsible for the variation in plasma density and its homogeneity. Non-uniformities in the plasma’s top/bottom and left/right distributions have been studied and partially addressed experimentally. The first issue was resolved by adjusting the radio-frequency power supplied to the plasma in different vertical regions, while the second issue was addressed by reversing the direction of the magnetic filter field and increasing the plasma density.