bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrafast modulation of a THz metamaterial/graphene array integrated device
Authors: Zaman Abdullah M. , Saito Yuichi , Lu Yuezhen , Kholid Farhan Nur , Almond Nikita W. , Burton Oliver J. , Alexander-Webber Jack , Hofmann Stephan , Mitchell Thomas , Griffiths Jonathan D. P. , Beere Harvey E. , Ritchie David A. , Mikhaylovskiy Rostislav V. , Degl'Innocenti Riccardo
Published: August 2022

We report on the ultrafast modulation of a graphene loaded artificial metasurface realized on a SiO2/Si substrate by near-IR laser pump, detected via terahertz probe at the resonant frequency of ∼0.8 THz. The results have been acquired by setting the Fermi energy of graphene at the Dirac point via electrostatic gating and illuminating the sample with 40 fs pump pulses at different fluences, ranging from 0.9 to 0.018 mJ/cm2. The sub-ps conductivity rising time was attributed to the combined effect of the ultrafast generation of hot carriers in graphene and electron–hole generation in silicon. In correspondence of the resonance, it was possible to clearly distinguish a partial recovery time of ∼2 ps mainly due to carrier-phonon relaxation in graphene, superimposed to the > 1 ns recovery time of silicon. The resonant metasurface yielded ∼6 dB modulation depth in E-field amplitude at 0.8 THz for the range of fluences considered. These measurements set an upper limit for the reconfiguration speed achievable by graphene-based terahertz devices. At the same time, this work represents a great progress toward the realization of an ultrafast THz optoelectronic platform for a plethora of applications, ranging from the investigation of the ultrastrong light-matter regime to the next generation wireless communications.
Structural prediction of anion thiolate protected gold clusters of [Au28+7n(SR)17+3n]− (n = 0–4)
Authors: Wang Endong , Ding Junxia , Han Wenhua , Luan Shixia
Published: August 2022

Structural prediction of thiolate-protected gold nanoclusters (AuNCs) with diverse charge states can enrich the understanding of this species. Untill now, the number of anion AuNCs is still deficient. In this work, a series of gold nanoclusters with negative total charge, including [Au28(SR)17]−, [Au35(SR)20]−, [Au42(SR)23]−, [Au49(SR)26]−, and [Au56(SR)29]−, are designed. Following a crystallized [Au23(SR)16]− prototype structure, the inner core of the newly predicted clusters is obtained through packing crossed Au7. Next, proper protecting thiolate ligands are arranged to fulfill the duet rule to obtain Au3(2e) and Au4(2e). Extensive analysis indicates that these clusters own high stabilities. Molecular orbital analysis shows that the orbitals for the populations of the valence electron locate at each Au3(2e) and Au4(2e), which demonstrates the reliability of the grand unified model. This work should be helpful for enriching the structural diversity of AuNCs.
Magnetic heating enhancement for oxygen evolution reaction on confined CoSe2 nanoparticles by alternating magnetic field
Authors: Ding Yan , Zhou Wenda , Luo Xingfang , Huang Jinli , Peng Dongquan , Chen Mingyue , Zhou Hang , Hu Ce , Yuan Cailei
Published: August 2022

Localized magnetic heating in magnetic nanoparticles caused by an alternating magnetic field (AMF) can facilitate electrocatalytic reactions, which has become an emerging strategy to further enhance overall efficiency of catalysts and frontier in an electrocatalysis field. However, the investigation of AMF-assisted electrocatalysis is still in its infancy, and how to efficiently utilize magnetic heating in magnetic nanoparticles to boost electrocatalysis reactions is in great demand. In this work, a feasible design is proposed by using Néel relaxation, efficient local heating generated in superparamagnetic CoSe2 nanoparticles confined in an amorphous carbon matrix by AMF leading to improved catalytic performance. The rapid oxygen evolution reaction enhancement of CoSe2 nanoparticles responses to switched on/off AMF, indicating that the localized magnetic heating is generated in catalysts by Néel relaxation with magnetic moments of nanoparticles rapidly flipping under AMF. Our work inspires insight to design AMF-assisted electrocatalysts and inject power into the field of electrocatalysis.
Development of efficient computational analysis of difference infrared and Raman spectroscopies
Authors: Hirano Tomonori , Yazawa Naoya , Wang Lin , Morita Akihiro
Published: August 2022

Computational analysis of difference spectra between two analogous systems is a challenging issue, as reliable estimation of a tiny difference spectrum requires an extraordinary precision of the two original spectra. We have developed an alternative new method to calculate the difference spectra under background-free conditions, which greatly improved the efficiency of computation. In this paper, we report further improvement by using efficient parallel implementation and the time correlation formula based on time derivative quantities. As a consequence, the present work achieved further remarkable acceleration in the calculations of difference infrared and Raman spectra in the order of magnitude and thereby allowed us by analyzing these difference spectra at a practical cost of computation.
Polarization-dependent unidirectional reflectionless in non-Hermitian metasurface and its application in near-field grayscale imaging
Authors: Gao Fan , Sun Zhiyu , Yuan Peicheng , Deng Juan , Jin Guoli , Zhou Jian , Liu Hao , Yan Bo
Published: August 2022

Recently, the non-Hermitian optical system draws much attention due to their peculiar optical properties. In this paper, a non-parity-time symmetric muti-layer metasurface is proposed. The polarization-dependent unidirectional reflectionless (UR) effect associated with the exceptional point (EP) is investigated. By adjusting the geometric parameters of the metasurface, the EP based UR phenomenon can be observed at 2360 nm, and the simulation results are in good agreement with the theoretical work. Unlike other isotropic non-Hermitian platforms, the proposed UR phenomenon has a strong dependence on the incident polarization state, which guarantees its great application potential in the fields of near-field imaging and optical encryption, etc.
Franck–Condon spectra of unbound and imaginary-frequency vibrations via correlation functions: A branch-cut free, numerically stable derivation
Authors: Changala P. Bryan , Genossar Nadav , Baraban Joshua H.
Published: August 2022

Molecular electronic spectra can be represented in the time domain as auto-correlation functions of the initial vibrational wavepacket. We present a derivation of the harmonic vibrational auto-correlation function that is valid for both real and imaginary harmonic frequencies. The derivation rests on Lie algebra techniques that map otherwise complicated exponential operator arithmetic to simpler matrix formulas. The expressions for the zero- and finite-temperature harmonic auto-correlation functions have been carefully structured both to be free of branch-cut discontinuities and to remain numerically stable with finite-precision arithmetic. Simple extensions correct the harmonic Franck–Condon approximation for the lowest-order anharmonic and Herzberg–Teller effects. Quantitative simulations are shown for several examples, including the electronic absorption spectra of F2, HOCl, CH2NH, and NO2.
Review of Scientific Instruments New Products
Authors: Mandelis Andreas
Published: August 2022

In order to supplement manufacturers’ information, this department will welcome the submission by our readers of brief communications reporting measurements on the physical properties of materials, which supersede earlier data or suggest new research applications.
Cadmium thiosulfate complexes can be assimilated by a green alga via a sulfate transporter but do not increase Cd toxicity
Authors: Boily Frédéric , Fortin Claude , Campbell Peter G. C.
Published: August 2022

Environmental context Thiosulfate is present in natural waters, especially those influenced by sulfide oxidation, and it has a marked affinity for metals such as cadmium. Normally the binding of cadmium by thiosulfate would be expected to reduce the metal’s bioavailability. However, here we demonstrate that algal uptake of cadmium is enhanced in the presence of thiosulfate, indicating that Cd can enter the alga via a novel route as an intact Cd-thiosulfate complex. Rationale For a given free metal ion activity in the exposure solution, the Biotic Ligand Model assumes that metal uptake will be independent of the various ligands present in solution that are buffering [Mz+]. In this context, we have evaluated cadmium bioavailability in the absence or presence of thiosulfate, using Chlamydomonas reinhardtii as the test alga. Methodology Short-term exposures (≤41 min) were run with a fixed concentration of the free Cd2+ ion (3.0 ± 0.1 nM), buffered with either nitrilotriacetate or thiosulfate, to determine Cd uptake. Subsequent long-term exposures (72 h) over a range of free Cd2+ concentrations were used to determine the effects of Cd on algal growth. Results Contrary to Biotic Ligand Model predictions, Cd uptake was enhanced when Cd2+ was buffered with thiosulfate. Removal of sulfate from this exposure medium increased Cd uptake; conversely, if [SO42−] was increased, Cd uptake decreased. In the absence of thiosulfate, Cd uptake was unaffected by changes in [SO42−]. In the long-term exposures, the cellular Cd quota needed to reduce algal growth by 50% was significantly higher in the presence of thiosulfate than in its absence. Discussion In the presence of thiosulfate, Cd can enter the algal cell not only by cation transport but also by transport of the intact Cd-thiosulfate complex via the anion transporter responsible for sulfate uptake. We speculate that some of the Cd taken up by anion transport remains in complexed form and is less bioavailable than the Cd that enters the cell via cation transport.
Sustaining sexual and reproductive health through COVID-19 pandemic restrictions: qualitative interviews with Australian clinicians
Authors: Newman Christy E. , Fraser Doug , Ong Jason J. , Bourne Christopher , Grulich Andrew E. , Bavinton Benjamin R.
Published: August 2022

Background The sexual and reproductive health care of people with HIV and those at risk of HIV has largely been delivered face-to-face in Australia. These services adapted to the coronavirus disease 2019 (COVID-19) pandemic with a commitment to continued care despite major impacts on existing models and processes. Limited attention has been paid to understanding the perspectives of the sexual and reproductive health care workforce in the research on COVID-19 adaptations. Methods Semi-structured interviews were conducted between June and September 2021 with 15 key informants representing a diverse range of service settings and professional roles in the Australian sexual and reproductive health sector. Inductive themes were generated through a process of reflexive thematic analysis, informed by our deductive interest in clinical adaptations. Results The major adaptations were: triage (rapidly adapting service models to protect the most essential forms of care); teamwork (working together to overcome ongoing threats to service quality and staff wellbeing), and the intwined themes of telehealth and trust (remaining connected to marginalised communities through remote care). Despite impacts on care models and client relationships, there were sustained benefits from the scaleup of remote care, and attention to service safety, teamwork and communication. Conclusions Attending to the experiences of those who worked at the frontline of the COVID-19 response provides essential insights to inform sustained, meaningful system reform over time. The coming years will provide important evidence of longer-term impacts of COVID-19 interruptions on both the users and providers of sexual and reproductive health services.
ITE provision in minority language contexts
Authors: Thomas Enlli M. , Dunne Claire M.
Published: August 2022

Within the broader contexts of language maintenance, revitalisation and use, schools have an important role to play in the early transmission of minority or minoritized languages. Through effective classroom-based practices, teachers can offer rich, continuous linguistic experiences for the young people they teach that can lead to long-term, sustained engagement with language over time. How effective a given approach or practice may be in delivering a linguistic outcome in different contexts depends to a large extent on the skills and competence of the teacher involved (Fitzpatrick et al., 2018, p. 59), and the skills and competence of the teacher are usually rooted in their early experiences as student teachers. Initial teacher education (ITE) programmes are therefore central to the delivery of effective classroom-based practices and fundamental in generating autonomous teachers who can explore critically the different pedagogical approaches as they pertain to minority language contexts. This paper provides a comparative overview of the current issues and challenges facing ITE for primary education in two distinct minority language settings, namely Wales and Ireland. Both settings provide Welsh-medium or Irish-medium immersion education, as well as English-medium education offering Welsh or Irish as statutory subjects up to age 16. Both contexts also offer ITE programmes through the medium of Welsh or Irish, catering specifically for those student teachers wishing to teach in immersion settings. Both contexts face a number of shared challenges in terms of the content, design and delivery of an effective ITE programme for the context. We therefore highlight areas in which resources and methodologies could be shared amongst all those involved in ITE where minority language maintenance is a key component of education.
Agreeing complementizers may just be moody
Authors: Demirok Ömer , Öztürk Balkız
Published: August 2022

This study investigates two discourse-related particles, ya and şo, in
Laz, an endangered South Caucasian language. We argue that both ya and şo are
indexical shift complementizers which can occur without an overt embedding verb, suggesting root
complementizer behavior. However, when they appear embedded, the mood specification of the embedding verb determines
which of the two will surface, suggestive of complementizer agreement in mood features. We show that, while
ya and şo need to be semantically distinct in their root occurrences, there are
compositionality challenges against the null hypothesis that ya and şo keep their
meanings when embedded. As an alternative to a formal agreement account, we propose to semantically relate the
embedded and root occurrences of these complementizers.
Effect of nonequilibrium order parameter on the optical response of superconductor Sr2RuO4
Authors: Yazdani-Hamid Meghdad
Published: August 2022

The breaking of time reversal symmetry of the superconducting pairings is expected to manifest itself through characteristic transport properties such as a non-zero Kerr angle which provides fingerprint of the quantum anomalous Hall state. In this work, we theoretically study the Kerr effect or the Hall-type response and also consider how this response is modified by the nonequilibrium shape of order parameter of the superconducting state due to the influence of the electromagnetic radiation for the most favorable candidates of chiral superconducting order parameters and of the non-chiral states in strontium ruthenate (Sr2RuO4). The unique sensitivity of the Hall-type response introduced above to different types of pairings can be used to identify the most favored pairing which is a serious doubt on the superconducting state of this material.
A novel dense residual network based on Adam-S optimizer for fault diagnosis of bearings under different working conditions
Authors: Han Fei , Du Wenhua , Zeng Zhiqiang , Wang Zhijian , Li Yanfeng , Wang Junyuan
Published: August 2022

In recent years, the residual network has been widely used in the field of intelligent diagnosis because of its powerful functioning. This paper proposes a novel dense residual network (DRNet) for the efficient fault diagnosis of rolling bearings, which combines the advantages of dense connections and residual learning to prevent the gradient disappearance and network degradation caused by network deepening. First, each sub-block in the dense network (DesNet) is deeply processed so that it has better nonlinear expressive ability to extract deep fault features. Then, the residual learning is embedded into each sub-block of the DesNet, so that each sub-block processed by deepening will not show the phenomenon of network degradation. Finally, an Adam-subtracted momentum optimization algorithm is proposed, which adds the first-order momentum and the second-order momentum of the previous gradient into the expression of the second-order momentum of the current gradient, which enhances the connection between the parameters in the two adjacent gradients in the Adam algorithm. It makes the algorithm more reliable and the gradient prediction more accurate. Without adding additional parameters, the training stability of the algorithm in complex environments is further improved. Experiments on two kinds of data sets under different working conditions are carried out many times, and in comparison with the random forest, support vector machine, dense network, residual network, AlexNet and DRNet-Adam. This proves the effectiveness and feasibility of the proposed model and optimization algorithm.
A transfer-learning fault diagnosis method considering nearest neighbor feature constraints
Authors: Zeng Mengjie , Li Shunming , Li Ranran , Li Jiacheng , Xu Kun , Li Xianglian
Published: August 2022

Aiming at the problem of low diagnostic accuracy of fault diagnosis models due to changes in actual operating conditions, a novel fault diagnosis method based on transfer learning considering nearest neighbor feature constraints is proposed. First, nearest neighbor samples are considered to measure data features. In addition, a nearest neighbor feature constraint strategy is designed to improve the feature extraction performance of the network. Second, a multiple-alignment strategy of nearest neighbor samples is proposed to enhance the domain adaptation performance of the network model utilizing multiple alignments. Then, a loss function dynamic weight strategy is used to improve the convergence of the loss function during model training. Finally, the experimental verification is carried out on the public data set of the Western Reserve University and the private data set. The experimental results show that the proposed method exhibits superior transfer performance with reliability and stability compared to the existing methods.
Wind turbine blade icing detection using a novel bidirectional gated recurrent unit with temporal pattern attention and improved coot optimization algorithm
Authors: Chen Wenhe , Cheng Longsheng , Chang Zhipeng , Wen Buyu , Li Ping
Published: August 2022

Blade icing detection is significant for the safe operation of wind turbines and to reduce power generation losses. Traditional additional sensor methods for monitoring are limited due to the high cost and damage to the original mechanical structure. The deep learning model shows a good performance for icing detection. This paper proposes a temporal pattern attention-based bidirectional gated recurrent unit (BiGRU-TPA). This novel deep learning framework incorporates the TPA module into the BiGRU module to determine the relationship between multiple sensors at different time steps, extracting features from the raw sensor data for discrimination. Meanwhile, its hyperparameters are optimized using an improved coot optimization algorithm (ICOOT) to further enhance its recognition performance. To alleviate the severe imbalance in the dataset, adaptive synthesis and the sliding window upsampling method are imported to oversample and sliding window the icing state samples, which belong to the minority class. ICOOT-BiGRU-TPA illustrates its advantages compared with other state-of-the-art baseline methods, widely used optimization algorithms, and attention mechanisms applied to the real icing dataset. The ablation study and sensitivity analysis also demonstrate the performance of crucial components in the proposed model. Furthermore, its feasibility and practicality are demonstrated by real-time icing detection.
Nucleus and nuclear fission-some interesting calculations
Authors: Khan F A
Published: August 2022

A number of useful and interesting exercises regarding nucleus and nuclear fission are performed to make these concepts more understandable to high school or even college students.
Dosimetric impact of intrafraction motion under abdominal compression during MR-guided SBRT for (Peri-) pancreatic tumors
Authors: Grimbergen Guus , Eijkelenkamp Hidde , Heerkens Hanne D , Raaymakers Bas W , Intven Martijn P W , Meijer Gert J
Published: August 2022

Objective. Intrafraction motion is a major concern for the safety and effectiveness of high dose stereotactic body radiotherapy (SBRT) in the upper abdomen. In this study, the impact of the intrafraction motion on the delivered dose was assessed in a patient group that underwent MR-guided radiotherapy for upper abdominal malignancies with an abdominal corset. Approach. Fast online 2D cine MRI was used to extract tumor motion during beam-on time. These tumor motion profiles were combined with linac log files to reconstruct the delivered dose in 89 fractions of MR-guided SBRT in twenty patients. Aside the measured tumor motion, motion profiles were also simulated for a wide range of respiratory amplitudes and drifts, and their subsequent dosimetric impact was calculated in every fraction. Main results. The average (SD) D
99% of the gross tumor volume (GTV), relative to the planned D
99%, was 0.98 (0.03). The average (SD) relative D
0.5cc
of the duodenum, small bowel and stomach was 0.99 (0.03), 1.00 (0.03), and 0.97 (0.05), respectively. No correlation of respiratory amplitude with dosimetric impact was observed. Fractions with larger baseline drifts generally led to a larger uncertainty of dosimetric impact on the GTV and organs at risk (OAR). The simulations yielded that the delivered dose is highly dependent on the direction of on baseline drift. Especially in anatomies where the OARs are closely abutting the GTV, even modest LR or AP drifts can lead to substantial deviations from the planned dose. Significance. The vast majority of the fractions was only modestly impacted by intrafraction motion, increasing our confidence that MR-guided SBRT with abdominal compression can be safely executed for patients with abdominal tumors, without the use of gating or tracking strategies.
Study of the radiation temperature on ablator by using the shock wave technique
Authors: Li Liling , Ren Guoli , Zhang Huan , Jing Longfei , Peng Xiaoshi , Chen Yaohua , Hu Xin , Zhang Lu , Li Jin , Yang Zhiwen , Hou Lifei , Zhang Wenhai , Cao Hui , Huo Wenyi , Li Hang , Zheng Jianhua , Lin Zhiwei , Shang Wanli , Lan Ke , Kuang Longyu , Yang Jiamin
Published: August 2022

A new diagnostic platform for more accurate diagnosis of the peak radiation temperature on ablator has been proposed. A nearly constant radiation temperature was obtained by two laser entrance holes spherical hohlraum. The peak radiation temperature on ablator was determined by the shock wave technique. A high-quality burn-through image of a two-step-shaped Au ablator was obtained in the experiment. The simulated mass ablation rate agrees well with the experimental result, while the peak radiation temperature measured by flat-response x-ray detectors outside the hohlraum was of ∼20 eV’s lower than that obtained by the shock wave technique. This deviation results in ∼20%’s decrease in the mass ablation rate in the simulation. Thus, the new diagnostic platform can provide more accurate peak radiation temperature diagnosis. This can greatly support the inertial confinement fusion ignition target design.
Gyrokinetic particle-in-cell simulations of electromagnetic turbulence in the presence of fast particles and global modes
Authors: Mishchenko A , Bottino A , Hayward-Schneider T , Poli E , Wang X , Kleiber R , Borchardt M , Nührenberg C , Biancalani A , Könies A , Lanti E , Lauber Ph , Hatzky R , Vannini F , Villard L , Widmer F
Published: August 2022

Global simulations of electromagnetic turbulence in circular-flux-surface tokamak and ASDEX-Upgrade geometry, tearing instabilities and their combination with the electromagnetic turbulence, nonlinear Alfvénic modes in the presence of fast particles and their combination with the electromagnetic turbulence and global electromagnetic turbulence in Wendelstein 7-X stellarator geometry are carried out using the gyrokinetic particle-in-cell code ORB5 (Lanti et al 2020 Comp. Phys. Comm.
251 107072) and EUTERPE (Kornilov et al 2004 Phys. Plasmas
11 3196). Computational feasibility of simulating such complex coupled systems is demonstrated. For simplicity, the reduced mass ratio is used throughout the paper.
Experimental study of the effect of argon on the restrike characteristics of nitrogen arc
Authors: Shao Ke , Sun Su-Rong , Meng Xian , Huang He-Ji , Hu Ya-Hao , Wang Hai-Xing
Published: August 2022

The arc restrike process is a typical mode of operation within a direct current arc plasma torch. By using a transfer arc device with a planar anode parallel to the gas flow direction, the effect of argon addition on the disappearance of downstream old arc roots, the overall arc downstream movement process and the generation of upstream new arc roots of the nitrogen arc restrike process is experimentally investigated. The experimental results show that for pure nitrogen arc, the restrike frequency is very high and the old arc root disappears very quickly. The addition of argon will significantly decrease the temperature of the arc root and prolong the coexistence time of the old and new arc roots. This phenomenon is caused by the rapid decay of charged particle density in the nitrogen arc, because the recombination process of charged particles in the nitrogen arc is faster than that in the argon arc. The breakdown field strength at the upstream location where the new arc root occurs is calculated by combining the measurements of arc voltage, arc grayscale image and temperature. The results show that as the percentage of argon increases, the boundary layer thickness becomes thinner and the critical electric field strength required for arc breakdown decreases, leading to the generation of new arc roots more likely to occur toward the upstream location. This study improves the understanding of the effect of argon on the nitrogen arc restrike process.
Low-power double-gate MoS2 negative capacitance transistors with near-zero DIBL
Authors: Hu Taiqi , Cheng Tiedong , Lin Yuan , Zhang Tianfu
Published: August 2022

Negative capacitance (NC) devices hold great promise for improving subthreshold slope (SS). However, the theoretical exploration of the short-channel effect in NC and two-dimensional (2D) materials remains an ongoing challenge in device scaling. The present work demonstrates a double-gate MoS2 negative capacitance field-effect transistor (MoS2 DG-NCFET) with low power and near-zero drain-induced barrier lowering (DIBL) by exploring its design space considering the impact of various MoS2 layers, with the aid of the developed 2D short-channel model containing the NC effect and numerical simulation. The proposed monolayer MoS2 DG-NCFET model is solved by unifying the long and short channel models coupled with the one-dimensional Landau-Khalatnikov equation. The study indicates that a lower SS, considerable voltage saving (

V

s
a
v
i
n
g

), and even the ability to achieve zero DIBL are seen in monolayer MoS2 devices when compared with those of non-2D MoS2, due to the combination of the atomic-scale thickness of channels and the double-gate structure. This study provides an insight for further reducing the feature size of ultralow power transistors.
Phonon heat capacity and self-heating normal domains in NbTiN nanostrips
Authors: Sidorova M , Semenov A D , Hübers H-W , Gyger S , Steinhauer S
Published: August 2022

Self-heating normal domains in thin superconducting NbTiN nanostrips with the granular structure were characterized via steady-state hysteretic current–voltage characteristics measured at different substrate temperatures. The temperature dependence and the magnitude of the current, which sustains a domain in equilibrium at different voltages, can only be explained with a phonon heat capacity noticeably less than expected for 3D Debye phonons. This reduced heat capacity coincides with the value obtained earlier from magnetoconductance and photoresponse studies of the same films. The rate of heat flow from electrons at a temperature

T

e

to phonons in the substrate at a temperature

T

B

is proportional to

(

T

e

p

−

T

B

p

)

with the exponent p ≈ 3, which differs from the exponents for heat flows mediated by the electron–phonon interaction or by escaping of 3D Debye phonons via the film/substrate interface. We attribute both findings to the effect of grains on the phonon spectrum of thin NbTiN films. Our findings are significant for understanding the thermal transport in superconducting devices exploiting thin granular films.
Electron capture and β-decay rates for nuclei with A = 65–80
Authors: Ullah Asim , Nabi Jameel-Un
Published: August 2022

Recently a list of top 50 most important electron capture (ec) and β-decay (bd) nuclei, averaged throughout the stellar trajectory for 0.500 > Y

e
> 0.400, was published. The current study presents the calculation of ec and bd rates, from the published list with A = 65–80, on a detailed temperature-density grid. The ec and bd rates were calculated using the proton-neutron quasiparticle random phase approximation model (pn-QRPA). Our calculation did not employ the Brink-Axel hypothesis. A systematic comparison of the current calculation with the previous pn-QRPA and independent particle model (IPM) results is presented for the first time. The reported ec rates are almost the same when compared with the previous pn-QRPA calculation. On the other hand, the reported bd rates are generally smaller up to an order of magnitude. Comparison with IPM results show that our calculated rates are bigger, by two orders of magnitude. The current calculation may contribute to a more realistic simulation of late phases of stellar evolution and modeling of x-ray bursts.
Neutrino point source searches for dark matter spikes
Authors: Freese Katherine , Galstyan Irina , Sandick Pearl , Stengel Patrick
Published: August 2022

Any dark matter spikes surrounding black holes in our Galaxy are sites of significant dark matter annihilation, leading to a potentially detectable neutrino signal. In this paper we examine 10 - 105
M
⊙ black holes associated with dark matter spikes that formed in early minihalos and still exist in our Milky Way Galaxy today, in light of neutrino data from the ANTARES [1] and IceCube [2] detectors. In various regions of the sky, we determine the minimum distance away from the solar system that a dark matter spike must be in order to have not been detected as a neutrino point source for a variety of representative dark matter annihilation channels. Given these constraints on the distribution of dark matter spikes in the Galaxy, we place significant limits on the formation of the first generation of stars in early minihalos — stronger than previous limits from gamma-ray searches in Fermi Gamma-Ray Space Telescope data. The larger black holes considered in this paper may arise as the remnants of Dark Stars after the dark matter fuel is exhausted; thus neutrino observations may be used to constrain the properties of Dark Stars. The limits are particularly strong for heavier WIMPs. For WIMP masses ∼ 5TeV, we show that ≲ 10 % of minihalos can host first stars that collapse into BHs larger than 103
M
⊙.
Timing and multi-channel:
novel method for determining the neutrino mass ordering from supernovae
Authors: Brdar Vedran , Xu Xun-Jie
Published: August 2022

One of the few remaining unknowns in the standard three-flavor neutrino oscillation paradigm is the ordering of neutrino masses. In this work we propose a novel method for determining neutrino mass ordering using the time information on early supernova neutrino events. In a core-collapse supernova, neutrinos are produced earlier than antineutrinos and, depending on the mass ordering which affects the adiabatic flavor evolution, may cause earlier observable signals in νe
detection channels than in others. Hence, the time differences are sensitive to the mass ordering. We find that using the time information on the detection of the first galactic supernova events at future detectors like DUNE, JUNO and Hyper-Kamiokande, the mass ordering can already be determined at
∼ 2σ CL, while 𝒪(10) events suffice for the discovery. Our method does not require high statistics and could be used within the supernova early warning system (SNEWS) which will have access to the time information on early supernova neutrino events recorded in a number of detectors. The method proposed in this paper also implies a crucial interplay between the mass ordering and the triangulation method for locating supernovae.
The tunneling wavefunction in Kantowski-Sachs quantum cosmology
Authors: Fanaras Georgios , Vilenkin Alexander
Published: August 2022

We use a path-integral approach to study the tunneling wave function in quantum cosmology with spatial topology S
1 × S
2 and positive cosmological constant (the Kantowski-Sachs model). If the initial scale factors of both S
1 and S
2 are set equal to zero, the wave function describes (semiclassically) a universe originating at a singularity. This may be interpreted as indicating that an S
1 × S
2 universe cannot nucleate out of nothing in a non-singular way. Here we explore an alternative suggestion by Halliwell and Louko that creation from nothing corresponds in this model to setting the initial volume to zero. We find that the only acceptable version of this proposal is to fix the radius of S
1 to zero, supplementing this with the condition of smooth closure (absence of a conical singularity). The resulting wave function predicts an inflating universe of high anisotropy, which however becomes locally isotropic at late times. Unlike the de Sitter model, the total nucleation probability is not exponentially suppressed, unless a Gauss-Bonnet term is added to the action.
Technologies and applications of silicon-based micro-optical electromechanical systems: A brief review
Authors: Chen Shanshan , Zhang Yongyue , Hong Xiaorong , Li Jiafang
Published: August 2022

Micro-optical electromechanical systems (MOEMS) combine the merits of micro-electromechanical systems (MEMS) and micro-optics to enable unique optical functions for a wide range of advanced applications. Using simple external electromechanical control methods, such as electrostatic, magnetic or thermal effects, Si-based MOEMS can achieve precise dynamic optical modulation. In this paper, we will briefly review the technologies and applications of Si-based MOEMS. Their basic working principles, advantages, general materials and micromachining fabrication technologies are introduced concisely, followed by research progress of advanced Si-based MOEMS devices, including micromirrors/micromirror arrays, micro-spectrometers, and optical/photonic switches. Owing to the unique advantages of Si-based MOEMS in spatial light modulation and high-speed signal processing, they have several promising applications in optical communications, digital light processing, and optical sensing. Finally, future research and development prospects of Si-based MOEMS are discussed.
Simulation of MoS2 stacked nanosheet field effect transistor
Authors: Shen Yang , Tian He , Ren Tianling
Published: August 2022

Transition metal dichalcogenides are nowadays appealing to researchers for their excellent electronic properties. Vertical stacked nanosheet FET (NSFET) based on MoS2 are proposed and studied by Poisson equation solver coupled with semi-classical quantum correction model implemented in Sentaurus workbench. It is found that, the 2D stacked NSFET can largely suppress short channel effects with improved subthreshold swing and drain induced barrier lowering, due to the excellent electrostatics of 2D MoS2. In addition, small-signal capacitance is extracted and analyzed. The MoS2 based NSFET shows great potential to enable next generation electronics.
Research on quantum well intermixing of 680 nm AlGaInP/GaInP semiconductor lasers induced by composited Si–Si3N4 dielectric layer
Authors: He Tianjiang , Liu Suping , Li Wei , Xiong Cong , Lin Nan , Zhong Li , Ma Xiaoyu
Published: August 2022

The optical catastrophic damage that usually occurs at the cavity surface of semiconductor lasers has become the main bottleneck affecting the improvement of laser output power and long-term reliability. To improve the output power of 680 nm AlGaInP/GaInP quantum well red semiconductor lasers, Si–Si3N4 composited dielectric layers are used to induce its quantum wells to be intermixed at the cavity surface to make a non-absorption window. Si with a thickness of 100 nm and Si3N4 with a thickness of 100 nm were grown on the surface of the epitaxial wafer by magnetron sputtering and PECVD as diffusion source and driving source, respectively. Compared with traditional Si impurity induced quantum well intermixing, this paper realizes the blue shift of 54.8 nm in the nonabsorbent window region at a lower annealing temperature of 600 °C and annealing time of 10 min. Under this annealing condition, the wavelength of the gain luminescence region basically does not shift to short wavelength, and the surface morphology of the whole epitaxial wafer remains fine after annealing. The application of this process condition can reduce the difficulty of production and save cost, which provides an effective method for upcoming fabrication.
A low-power high-quality CMOS image sensor using 1.5 V 4T pinned photodiode and dual-CDS column-parallel single-slope ADC
Authors: Xu Wenjing , Chen Jie , Kuang Zhangqu , Zhou Li , Chen Ming , Zhang Chengbin
Published: August 2022

This paper presents a low-power high-quality CMOS image sensor (CIS) using 1.5 V 4T pinned photodiode (4T-PPD) and dual correlated double sampling (dual-CDS) column-parallel single-slope ADC. A five-finger shaped pixel layer is proposed to solve image lag caused by low-voltage 4T-PPD. Dual-CDS is used to reduce random noise and the nonuniformity between columns. Dual-mode counting method is proposed to improve circuit robustness. A prototype sensor was fabricated using a 0.11 µm CMOS process. Measurement results show that the lag of the five-finger shaped pixel is reduced by 80% compared with the conventional rectangular pixel, the chip power consumption is only 36 mW, the dynamic range is 67.3 dB, the random noise is only 1.55 e–
rms, and the figure-of-merit is only 1.98 e–·nJ, thus realizing low-power and high-quality imaging.
Interlocked MXene/rGO aerogel with excellent mechanical stability for a health-monitoring device
Authors: Zhao Shufang , Ran Wenhao , Wang Lili , Shen Guozhen
Published: August 2022

Two-dimensional (2D) materials have attracted considerable interest thanks to their unique electronic/physical–chemical characteristics and their potential for use in a large variety of sensing applications. However, few-layered nanosheets tend to agglomerate owing to van der Waals forces, which obstruct internal nanoscale transport channels, resulting in low electrochemical activity and restricting their use for sensing purposes. Here, a hybrid MXene/rGO aerogel with a three-dimensional (3D) interlocked network was fabricated via a freeze-drying method. The porous MXene/rGO aerogel has a lightweight and hierarchical porous architecture, which can be compressed and expanded several times without breaking. Additionally, a flexible pressure sensor that uses the aerogel as the sensitive layer has a wide response range of approximately 0–40 kPa and a considerable response within this range, averaging approximately 61.49 kPa–1. The excellent sensing performance endows it with a broad range of applications, including human-computer interfaces and human health monitoring.
Wireless networks of injectable microelectronic stimulators based on rectification of volume conducted high frequency currents
Authors: García-Moreno Aracelys , Comerma-Montells Albert , Tudela-Pi Marc , Minguillon Jesus , Becerra-Fajardo Laura , Ivorra Antoni
Published: August 2022

Objective. To develop and in vivo demonstrate threadlike wireless implantable neuromuscular microstimulators that are digitally addressable. Approach. These devices perform, through its two electrodes, electronic rectification of innocuous high frequency current bursts delivered by volume conduction via epidermal textile electrodes. By avoiding the need of large components to obtain electrical energy, this approach allows the development of thin devices that can be intramuscularly implanted by minimally invasive procedures such as injection. For compliance with electrical safety standards, this approach requires a minimum distance, in the order of millimeters or a very few centimeters, between the implant electrodes. Additionally, the devices must cause minimal mechanical damage to tissues, avoid dislocation and be adequate for long-term implantation. Considering these requirements, the implants were conceived as tubular and flexible devices with two electrodes at opposite ends and, at the middle section, a hermetic metallic capsule housing the electronics. Main results. The developed implants have a submillimetric diameter (0.97 mm diameter, 35 mm length) and consist of a microcircuit, which contains a single custom-developed integrated circuit, housed within a titanium capsule (0.7 mm diameter, 6.5 mm length), and two platinum–iridium coils that form two electrodes (3 mm length) located at opposite ends of a silicone body. These neuromuscular stimulators are addressable, allowing to establish a network of microstimulators that can be controlled independently. Their operation was demonstrated in an acute study by injecting a few of them in the hind limb of anesthetized rabbits and inducing controlled and independent contractions. Significance. These results show the feasibility of manufacturing threadlike wireless addressable neuromuscular stimulators by using fabrication techniques and materials well established for chronic electronic implants. Although long-term operation still must be demonstrated, the obtained results pave the way to the clinical development of advanced motor neuroprostheses formed by dense networks of such wireless devices.
Mode structure measurements of ion cyclotron emission and sub-cyclotron modes on DIII-D
Authors: DeGrandchamp G.H. , Lestz J.B. , Van Zeeland M.A. , Du X.D. , Heidbrink W.W. , Thome K.E. , Crocker N.A. , Pinsker R.I.
Published: August 2022

We report mode structure measurements of coherent ion cyclotron emission (ICE) and sub-cyclotron modes on DIII-D. Through a dedicated experiment, we aimed to characterize a variety of modes via the upgraded ICE diagnostic in both L- and H-mode plasmas. In the L-mode plasmas, autopower spectrum peaks at harmonics of the ion cyclotron frequency f
ci were observed and are localized in the core of the plasma. Sub-cyclotron modes (f ∼ 0.5f
ci) were also observed in L-mode plasmas when the toroidal magnetic field strength was lowered from B
T = 2.17 T. In H-mode plasmas, many ICE harmonics localized to the plasma edge were observed, with some exceeding the nominal ICE diagnostic bandwidth of f ∈ [0, 100] MHz. Polarization estimates made using an orthogonal pair of vertical and horizontal magnetic pickup loops on the outer wall of the machine indicate that ICE and sub-cyclotron modes have compressional polarization at the plasma edge, the latter being consistent with simulation efforts for comparable DIII-D plasmas. For all modes, the same harmonics are observed on both the centerpost and outer wall loops, indicating that ICE is poloidally extended. Finally, toroidal mode numbers were calculated using three outer wall loops for both core ICE and sub-cyclotron modes in L-mode plasmas. The sub-cyclotron case served as a benchmark for our calculation method, with measured numbers of n ∈ [−24, −18] roughly agreeing with heuristic estimates of n ∈ [−20, −13]. Core ICE mode numbers were measured to be n ∈ [−10, 5], which is comparable to measurements made on other machines.
Using Simulation to Estimate Parameters and Reliability for Alpha Power Rayleigh Distribution
Authors: Eidi Jaafer Hmood , Abdulsahib Ali Adnan
Published: August 2022

In this research, the parameters and reliability of the Alpha Power Rayleigh distribution were estimated by each of the moments method, the modification moment method, the percentile method and the maximum likelihood estimation method. The simulation technique was used to generate the data required for estimation and for different sample sizes and its replicate to 1000. The mean square error criterion was used to compare the obtained results. In general, the results of the estimators show that maximum likelihood estimation method is the best in estimating each of the parameters and the reliability function.
Adomian Decomposition Tarig Transform Method
Authors: Shaheed N H , Muhammad Y
Published: August 2022

Adomian decomposition Tarig transform technique (ADTTM) is a new variant of the A domian decomposition method for solving various models of partial differential equations. The Adomian decomposition method and the Tarig transform are combined in the ADTTM. The research makes extensive use of concrete instances. For many linear and nonlinear models, the new modification provides a useful tool.
Space-Time Petrov-Discontinuous Galerkin Finite Element Method for Solving Linear Convection-Diffusion Problems
Authors: AbdulRidha Mohammed Waleed , Kashkool Hashim A
Published: August 2022

The paper presents the theory of the space-time Petrov-discontinuous Galerkin finite element (PDGFE) method for the discretization of the nonstationary linear convection-diffusion problems. The PDGFE method is modified for the discontinuous Galerkin finite element (DGFE) method in the case of the symmetric interior penalty Galerkin (SIPG) scheme. PDGFE method is applied separately in space using different space gride on different time levels. We prove the properties of the bilinear form aPD, m
(u, ν) (V − elliptic and continuity) stability and prove the approximate solution converges with the error of order o (h
2 + τ
3). A numerical experiment is carried out to confirm the theoretical conclusions.
Using Fuzzy Aboodh Transform to Solve A System of First Order Fuzzy Linear Differential Equations
Authors: Alshibley Samer Thaaban Abaas , Albukhuttar Athraa Neamah , Alkiffai Ameera Nema
Published: August 2022

In this paper, fuzzy Aboodh transform used to solve system of fuzzy linear differential equations of first order in dimension two. Moreover, support work with an applied example in one of the institution.
Dominant cell method for the best linear assignment
Authors: Alhussein Sabah F Abd
Published: August 2022

This research aims to present a new method for best solution (B.S) of assignment problem (A.P) in linear programming (L.P). It is like the method by which one can find the (B.S) of transportation problem (T.P) using the dominant cells (D.C) that was called (D.C.T) method.Since the (A.P) is different from (T.P) in some features, the researcher has made changes in the conditions of (D.C.T) in order to determine the dominant cell for assignment (D.C.A). At last, the researcher has applied his method of (D.C.A) beside Hungarian method on several (A.P) and found it to be the best.