bluuebunny/crossref_metadata_2025 huggingface dataset:
Vanadium dioxide embedded frequency reconfigurable metasurface for multi-dimensional multiplexing of terahertz communication
Authors: Wang Ling , Yang Yang , Deng Li , Hong Weijun , Zhang Chen , Li Shufang
Published: March 2021

Multi-dimensional multiplexing based on the broadband metasurface is a promising candidate for the next generation terahertz (THz) communication system, which has become a research focus for data transmission rate and channel capacity enhancement. This paper proposes a THz frequency-reconfigurable metasurface hybridized with vanadium dioxide (VO2) for communication multiplexing on both dimensions of orbital angular momentum and frequency. Theoretically, 4 × n channel (n can be any positive integer) orthogonal coaxial beams carrying different data flow can be simultaneously generated based on the proposed metasurface in the tunable operating frequency band. The simulation results verify that the THz incident waves can be converted into orthogonal coaxial beams with different topological charges or frequencies, propagating perpendicular to the metasurface, when eight-channel oblique incident plane waves with varying angles or at various frequencies are reflected by the metasurface. The multi-dimensional multiplexing can be achieved in the frequency range of 0.29–0.39 THz and 0.24–0.34 THz with the VO2 switching between its fully insulating and metallic state. The proposed metasurface is expected to enable multi-band and broadband applications and has significant potential in high-speed and high-capacity THz communication.
Gas sensing near exceptional points
Authors: Nie Ping , Sheng Lijuan , Xie Linguo , Chen Zhihao , Zhou Xinxing , Chen Yu , Lin Xiao
Published: March 2021

Here we investigate the possibility of gas sensing with ultrahigh sensitivity by exploiting the exceptional point (EP) in a non-Hermitian system. The underlying mechanism is that the transverse displacement induced by the photonic spin Hall effect (PSHE), which is significantly enhanced near EPs, is ultra-sensitive to the variation of refractive index in gas media. With the application of the weak measurement technique, we find that the sensitivity of the gas sensing can reach

10

−
6

RIU 

μ

m

−
1

. Moreover, if we further reduce the in-plane wavevector component of probe Gaussian light, the sensitivity can be readily improved, up to

10

−
8

RIU 

μ

m

−
1

, which is much better than that of previous PSHE-based gas sensors operating away from the EP. Therefore, our proposed scheme may be favorable for the development of high-performance sensors.
Control of electromagnetic properties during prototyping, fabrication and operation of low-β 325 MHz half-wave resonators
Authors: Bychanok D , Sukhotski A , Huseu S , Vasilevich E , Gurnevich E , Volunets H , Liubetski N , Maksimenko S , Shvedov A , Petrakovski V , Pakrouski A , Yurevich S , Tamashevich Y , Gusarova M , Lalayan M , Polozov S , Butenko A , Syresin E
Published: March 2021

The general steps for the fabrication of a copper prototype of 325 MHz coaxial half-wave resonator (HWR) with β = 0.21 are presented and discussed in this work. The main features for the control of the electromagnetic properties during the manufacturing process of HWR are described in detail. The resonant frequency sensitivity to the accelerating gap and to the cavity height were experimentally estimated. Bead-pull measurements were performed and the electric field distribution along the beam axis of the manufactured cavity was estimated. The features of the cavity’s response in the critical coupling regime are analyzed. The experimental concept of a slow frequency tuning system (FTS) based on the moving plungers is proposed and tested. The tuning sensibility is experimentally estimated. The measured results agree with the simulations quite well, and the sensitivity for a single plunger configuration

Δ
f

/

Δ
L
=
+
13

kHz mm−1 is achieved. The dynamic properties and operation algorithm of the FTS are studied and experimentally investigated.
Multiple pseudo-plateaux states and antiferromagnetic pair selection in the XY model in the highly frustrated honeycomb lattice
Authors: Gómez Albarracín F A , Rosales H D
Published: March 2021

We present a study of the low temperature magnetic phases of the classical XY model with third nearest neighbor interactions on the honeycomb lattice at the maximally frustrated point under an external magnetic field by extensive Monte Carlo simulations. We focus on the characterization of the emergent low temperature phases, which are a direct consequence of the unusually high numbers of spins per plaquette in the model. Specifically, we show that, since thermal fluctuations partially lift the ground-state degeneracy and select the most collinear states, the selected states are those with the highest number of ‘antiferromagnetic pairs’ (AFp) compatible with the external magnetic field. These AFp are formed in such a way that they maximize the degeneracy of the selected submanifold of ground states. Moreover, two collinear pseudoplateaux emerge at M = 1/3 and M = 2/3. To characterize the magnetization process, we employ Monte Carlo simulations and calculate relevant order parameters to construct the complete temperature vs magnetic field phase diagram.
A simple method to calculate solution-phase free energies of charged species in computational electrocatalysis
Authors: Granda-Marulanda Laura P , McCrum Ian T , Koper Marc T M
Published: March 2021

Determining the adsorption potential of adsorbed ions in the field of computational electrocatalysis is of great interest to study their interaction with the electrode material and the solvent, and to map out surface phase diagrams and reaction pathways. Calculating the adsorption potentials of ions with density functional theory and comparing across various ions requires an accurate reference energy of the ion in solution and electrons at the same electrochemical scale. Here we highlight a previously used method for determining the reference free energy of solution phase ions using a simple electrochemical thermodynamic cycle, which allows this free energy to be calculated from that of a neutral gas-phase or solid species and an experimentally measured equilibrium potential, avoiding the need to model solvent around the solution phase ion in the electronic structure calculations. While this method is not new, we describe its use and utility in detail and show that this same method can be used to find the free energy of any ion from any reaction, as long as the half-cell equilibrium potential is known, even for reactions that do not transfer the same number of protons and electrons. To illustrate its usability, we compare the adsorption potentials obtained with DFT of I*, Br*, Cl*, and SO4
* on Pt(111) and Au(111) and OH* and Ag* on Pt(111) with those measured experimentally and find that this simple and computationally affordable method reproduces the experimental trends.
Novel electric field effects on magneto-optical conductivity in eight-Pmmn borophene
Authors: Li Jing , Sun Yanmei , Wu Meimei , Pan Hui
Published: March 2021

We theoretically study the Landau levels and the magneto-optical conductivity of eight-Pmmn borophene in the presence of a perpendicular magnetic field and an inplane electric field. We find that in the absence of the inplane electric field, the magneto-optical conductivity of eight-Pmmn borophene presents a series of striking single resonance peaks as functions of the frequency ω, and the longitudinal conductivities are found to be anisotropic due to its anisotropic tilted Dirac cones. In the presence of the inplane electric field, some novel effects are predicted on the Landau levels and the magneto-optical conductivity. The Landau level spacings in the two tilted Dirac cones are different, which lifts the degeneracy of the twofold valley, and the magneto-optical conductivity appears a double peak structure. We also discuss the influence of the chemical potential between different Landau levels on the double peak of the magneto-optical response. The valley related magneto-optical properties in the anisotropic structure may make eight-Pmmn borophene a candidate for the new optical devices.
Rehabilitation of the former nuclear test site at Maralinga
Authors: Long Stephen , Cook Megan , Charalambous Fiona , Carpenter Julia
Published: March 2021

Large areas of the former British nuclear test site at Maralinga were contaminated by the explosive dispersal of plutonium. The Australian Government, in consultation with stakeholders, determined that the site should be cleaned-up so that it is fit for unrestricted habitation by the Aboriginal traditional owners (Maralinga Tjarutja). Engagement with the stakeholders, particularly the Maralinga Tjarutja, determined that the specific criterion for rehabilitation was 5 mSv y−1 and that some restrictions on permanent occupancy should remain. Remediation of the site began in 1995, took 5 years and cost AU$106 million. The site was returned to its traditional owners in 2009 and is now the site of a flourishing tourism operation.
A signal quality analysis method for electrocardiosignals in the CS domain
Authors: Liu Jizhong , Xu Wenbin , Zhao Peng , Hua Jing
Published: March 2021

Compressed sensing (CS) is an important cutting-edge low-power technology for wearable health monitoring systems. To solve the problem of how the quality of compressive sampled electrocardiosignal (ECG) affects the subsequent arrhythmia recognition and signal reconstruction, a novel ECG quality evaluation method in the CS domain is proposed. In order to achieve the evaluation effect in the CS domain, a modified bandpass filter method is designed to obtain the approximate frequency band energy and approximate wavelet entropy, which are used as the evaluation index for the support vector machine classifier to realize the CS ECG signal quality evaluation. Based on the simulation results from the MIT-BIH ECG database, this method can reach an accuracy of more than 92% under different compression ratios (2, 4, 8 and 16). Simulation experiments based on data from the PhysioNet/CinC Challenge 2011 database show that the accuracy of this method can reach above 83% under different compression ratios. In evaluation experiments using actual ECG signals, we show that this method can achieve good accuracy when the compression ratio is less than eight. The accuracy of this method needs to be further improved when the compression ratio is 16. When the compression ratio is less than 8 and a sparse matrix is not used as the measurement matrix, the method proposed in this paper can directly evaluate the quality of ECG signals after compression sampling without reconstruction. Compared with the signal quality evaluation algorithm in the uncompressed domain, the experimental results of the proposed method are highly competitive and, under a certain compression ratio, the amount of transmitted data can be reduced while maintaning accuracy. Meanwhile, the proposed method also provides a new idea for signal quality evaluation in the compressed domain.
On the role of excitation pulse duration on luminescence measurements
Authors: Allison Stephen W
Published: March 2021

Described here is an investigation into the effects of excitation pulse duration on the temporal character of luminescence of three characteristic thermographic phosphors: Mg4FGeO6:Mn, La2O2S:Eu, and YAG:Dy. Attention is first given to the build-up of the emission while the excitation pulse is on and its relation to temperature. Next, effects after pulse termination are addressed. For emission comprised of two or more characteristic decays, increasing the pulse duration will enhance the longer components relative to the shorter. For La2O2S:Eu, increasing the duration increases emission of successively longer-lived emitting states; and they display pronounced temperature dependence. For YAG:Dy, as excitation duration is increased, the main decay component used for thermometry is enhanced relative to two shorter components of less interest.
Facile aqueous synthesis of ZnInS quantum dots and its application for selective detection of Co2+ Ions
Authors: Zikalala Nkosingiphile , Parani Sundararajan , Oluwafemi Oluwatobi Samuel
Published: March 2021

The synthesis of ZnInS (ZIS) quantum dots (QDs) in aqueous medium using thioglycolic acid (TGA) and sodium citrate as dual capping agents has been reported. The as-synthesized ZIS QDs were water soluble, emitting at 512 nm and nearly spherical in shape with average particle size of 8.9 ± 1.4 nm. The as-synthesized ZIS QDs were tested for its fluorescence response against different metal ions and the results revealed that ZIS QDs were selectively quenched by Co2+ ions compared to other ions. The fluorescence sensing experiment showed that ZIS QDs has a linear response against the concentration of Co2+ ions (0.1–100 μM ) with the detection limit of 0.099 μM. Based on the transmission electron microscope and absorption spectroscopy analyzes, the fluorescence quenching is attributed to the formation of surface ligand-metal complex (TGA-Co2+ ions) which caused aggregation of the QDs. The present method explores the synthesis of zero-dimentional ZIS QDs and its potential in the selective detection of Co2+ ions in aqueous solution.
Flexible FeS@Fe2O3/CNT composite films as self-supporting anodes for high-performance lithium-ion batteries
Authors: Zhang Yaling , Chang Shulong , Zhang Ding , Zhang Sen , Han Lei , Ye Li , Pang Rui , Shang Yuanyuan , Cao Anyuan
Published: March 2021

The transition metal sulfides/oxides have been considered as promising anode materials for lithium ion batteries due to their high theoretical capacities but have suffered limits from the unsatisfactory electronic conductivity and limited lifespan. Here, FeS micro-flowers are synthesized by hydrothermal treatment and are wared and grafted into layer-by-layer carbon nanotubes (CNT). Subsequently, FeS@Fe2O3/CNT composite films are obtained by annealing, during which the FeS micro-flowers are partially oxidized to core–shell FeS@Fe2O3 micro-flowers. The FeS@Fe2O3/CNT composite electrodes exhibited high reversible capacity of 1722.4 mAh g−1 (at a current density of 0.2 A g−1 after 100 cycles) and excellent cycling stability (545.1 mAh g−1 at a current density of 2 A g−1 after 600 cycles) as self-supporting anodes. The prominent electrochemical performances are attributed to the unique reciprocal overlap architecture. This structure serves as a cushion to buffer large volume expansion during discharge/charge cycles, and ameliorates electrical conductivity. Due to their good specific capacity and cycle stability, these FeS@Fe2O3/CNT films have high potential application value to be used as high-performance anodes for lithium-ion, lithium sulfur and flexible packaging batteries.
Simulation tool for predicting and optimizing the performance of nanoparticle based strain sensors
Authors: Aslanidis Evangelos , Skotadis Evangelos , Tsoukalas Dimitris
Published: March 2021

In this work a Monte-Carlo tool simulating platinum nanoparticle (NP) based strain-sensors, on flexible substrates, is presented. The tool begins by randomly placing the NPs on the simulation area, with the ability to tune the NP surface coverage. After the calculation of the conductive paths that were generated in the previous step, the whole system is represented with an equivalent circuit; the NPs and the NP clusters act as nodes and the inter-particle gaps as resistances. The effective resistance is then calculated with the use of a Laplacian Matrix, which has proven extremely effective in significantly reducing the overall computational time. The simulation results are then benchmarked with experimental measurements from actual strain-sensing devices. The software is capable of predicting the strain-sensitivity for different NP sizes as well as surface coverages, emerging as a powerful computational tool for design-optimization of NP based devices in polymeric substrates, while it could well be extended to other nanocomposite materials used in flexible or stretchable electronic applications.
Self-organization of random copolymers to nanopatterns by localized e-beam dosing
Authors: Pandey Ankur , Maity Surjendu , Murmu Kaniska , Middya Sagnik , Bandyopadhyay Dipankar , Gooh Pattader Partho Sarathi
Published: March 2021

Strategic electron beam (e-beam) irradiation on the surface of an ultrathin (<100 nm) film of polystyrene–poly(methyl methacrylate) (PS-PMMA) random copolymer followed by solvent annealing stimulates a special variety of dewetting, leading to large-area hierarchical nanoscale patterns. For this purpose, initially, a negative (positive) tone of resist PS (PMMA) under weak e-beam exposure is exploited to produce an array of sites composed of cross-linked PS (chain-scissioned PMMA). Subsequently, annealing with the help of a developer solvent engenders dewetted patterns in the exposed zones where PMMA blocks are confined by the blocks of cross-linked PS. The e-beam dosage was systematically varied from 180 μC cm−2 to 10 000 μC cm−2 to explore the tone reversal behavior of PMMA on the dewetted patterns. Remarkably, at relatively higher e-beam dosing, both PMMA and PS blocks act as negative tones in the exposed zone. In contrast, the chain scission of PMMA in the periphery of the exposed regions due to scattered secondary electrons caused confined dewetting upon solvent annealing. Such occurrences eventually lead to pattern miniaturization an order of magnitude greater than with conventional thermal or solvent vapor annealed dewetting. Selective removal of PMMA blocks of RCP using a suitable solvent provided an additional 50% reduction in the size of the dewetted features.
Sparse channel sampling for ultrasound localization microscopy (SPARSE-ULM)
Authors: Hardy Erwan , Porée Jonathan , Belgharbi Hatim , Bourquin Chloé , Lesage Frédéric , Provost Jean
Published: March 2021

Ultrasound localization microscopy (ULM) has recently enabled the mapping of the cerebral vasculature in vivo with a resolution ten times smaller than the wavelength used, down to ten microns. However, with frame rates up to 20000 frames per second, this method requires large amount of data to be acquired, transmitted, stored, and processed. The transfer rate is, as of today, one of the main limiting factors of this technology. Herein, we introduce a novel reconstruction framework to decrease this quantity of data to be acquired and the complexity of the required hardware by randomly subsampling the channels of a linear probe. Method performance evaluation as well as parameters optimization were conducted in silico using the SIMUS simulation software in an anatomically realistic phantom and then compared to in vivo acquisitions in a rat brain after craniotomy. Results show that reducing the number of active elements deteriorates the signal-to-noise ratio and could lead to false microbubbles detections but has limited effect on localization accuracy. In simulation, the false positive rate on microbubble detection deteriorates from 3.7% for 128 channels in receive and 7 steered angles to 11% for 16 channels and 7 angles. The average localization accuracy ranges from 10.6 μm and 9.93 μm for 16 channels/3 angles and 128 channels/13 angles respectively. These results suggest that a compromise can be found between the number of channels and the quality of the reconstructed vascular network and demonstrate feasibility of performing ULM with a reduced number of channels in receive, paving the way for low-cost devices enabling high-resolution vascular mapping.
A feature invariant generative adversarial network for head and neck MRI/CT image synthesis
Authors: Touati Redha , Le William Trung , Kadoury Samuel
Published: March 2021

With the emergence of online MRI radiotherapy treatments, MR-based workflows have increased in importance in the clinical workflow. However proper dose planning still requires CT images to calculate dose attenuation due to bony structures. In this paper, we present a novel deep image synthesis model that generates in an unsupervised manner CT images from diagnostic MRI for radiotherapy planning. The proposed model based on a generative adversarial network (GAN) consists of learning a new invariant representation to generate synthetic CT (sCT) images based on high frequency and appearance patterns. This new representation encodes each convolutional feature map of the convolutional GAN discriminator, leading the training of the proposed model to be particularly robust in terms of image synthesis quality. Our model includes an analysis of common histogram features in the training process, thus reinforcing the generator such that the output sCT image exhibits a histogram matching that of the ground-truth CT. This CT-matched histogram is embedded then in a multi-resolution framework by assessing the evaluation over all layers of the discriminator network, which then allows the model to robustly classify the output synthetic image. Experiments were conducted on head and neck images of 56 cancer patients with a wide range of shape sizes and spatial image resolutions. The obtained results confirm the efficiency of the proposed model compared to other generative models, where the mean absolute error yielded by our model was 26.44(0.62), with a Hounsfield unit error of 45.3(1.87), and an overall Dice coefficient of 0.74(0.05), demonstrating the potential of the synthesis model for radiotherapy planning applications.
Scalable electronic readout design for a 100 ps coincidence time resolution TOF-PET system
Authors: Pourashraf Shirin , Gonzalez-Montoro Andrea , Won Jun Yeon , Lee Min Sun , Cates Joshua W , Zhao Zhixiang , Lee Jae Sung , Levin Craig S
Published: March 2021

We have developed a scalable detector readout design for a 100 ps coincidence time resolution (CTR) time of flight (TOF) positron emission tomography (PET) detector technology. The basic scintillation detectors studied in this paper are based on 2 × 4 arrays of 3 × 3 × 10 mm3 ‘fast-LGSO:Ce’ scintillation crystals side-coupled to 6 × 4 arrays of 3 × 3 mm2 silicon photomultipliers (SiPMs). We employed a novel mixed-signal front-end electronic configuration and a low timing jitter Field Programming Gate Array-based time to digital converter for data acquisition. Using a 22Na point source, >10 000 coincidence events were experimentally acquired for several SiPM bias voltages, leading edge time-pickoff thresholds, and timing channels. CTR of 102.03 ± 1.9 ps full-width-at-half-maximum (FWHM) was achieved using single 3 × 3 × 10 mm3 ‘fast-LGSO’ crystal elements, wrapped in Teflon tape and side coupled to a linear array of 3 SiPMs. In addition, the measured average CTR was 113.4 ± 0.7 ps for the side-coupled 2 × 4 crystal array. The readout architecture presented in this work is designed to be scalable to large area module detectors with a goal to create the first TOF-PET system with 100 ps FWHM CTR.
Comparative optic and dosimetric characterization of the HYPERSCINT scintillation dosimetry research platform for multipoint applications
Authors: Jean Emilie , Therriault-Proulx François , Beaulieu Luc
Published: March 2021

This study introduces the HYPERSCINT research platform (HYPERSCINT-RP100, Medscint Inc., Quebec, Canada), the first commercially available scintillation dosimetry platform capable of multi-point dosimetry through the hyperspectral approach. Optic and dosimetric performances of the system were investigated through comparison with another commercially available solution, the Ocean Optics QE65Pro spectrometer. The optical characterization was accomplished by measuring the linearity of the signal as a function of integration time, photon detection efficiency and spectral resolution for both systems under the same conditions. Dosimetric performances were then evaluated with a 3-point plastic scintillator detector (mPSD) in terms of signal to noise ratio (SNR) and signal to background ratio (SBR) associated with each scintillator. The latter were subsequently compared with those found in the literature for the Exradin W1, a single-point plastic scintillator detector. Finally, various beam measurements were realized with the HYPERSCINT platform to evaluate its ability to perform clinical photon beam dosimetry. Both systems were found to be comparable in terms of linearity of the signal as a function of the intensity. Although the QE65Pro possesses a higher spectral resolution, the detection efficiency of the HYPERSCINT is up to 1000 time greater. Dosimetric measurements shows that the latter also offers a better SNR and SBR, surpassing even the SNR of the Exradin W1 single-point PSD. While doses ranging from 1 to 600 cGy were accurately measured within 2.1% of the predicted dose using the HYPERSCINT platform coupled to the mPSD, the Ocean optics spectrometer shows discrepancies up to 86% under 50cGy. Similarly, depth dose, full width at half maximum region of the beam profile and output factors were all accurately measured within 2.3% of the predicted dose using the HYPERSCINT platform and exhibit an average difference of 0.5%, 1.6% and 0.6%, respectively.
What recording duration is required to provide physiologically valid and reliable dynamic cerebral autoregulation transfer functional analysis estimates?
Authors: Burma Joel S , Miutz Lauren N , Newel Kailey T , Labrecque Lawrence , Drapeau Audrey , Brassard Patrice , Copeland Paige , Macaulay Alannah , Smirl Jonathan D
Published: March 2021

Objective. Currently, a recording of 300 s is recommended to obtain accurate dynamic cerebral autoregulation estimates using transfer function analysis (TFA). Therefore, this investigation sought to explore the concurrent validity and the within- and between-day reliability of TFA estimates derived from shorter recording durations from squat-stand maneuvers.Approach. Retrospective analyses were performed on 70 young, recreationally active or endurance-trained participants (17 females; age: 26 ± 5 years, [range: 20–39 years]; body mass index: 24 ± 3 kg m−2). Participants performed 300 s of squat-stands at frequencies of 0.05 and 0.10 Hz, where shorter recordings of 60, 120, 180, and 240 s were extracted. Continuous transcranial Doppler ultrasound recordings were taken within the middle and posterior cerebral arteries. Coherence, phase, gain, and normalized gain metrics were derived. Bland–Altman plots with 95% limits of agreement (LOA), repeated measures ANOVA’s, two-tailed paired t-tests, coefficient of variation, Cronbach’s alpha, intraclass correlation coefficients, and linear regressions were conducted.Main results. When examining the concurrent validity across different recording durations, group differences were noted within coherence (F(4155) > 11.6,p < 0.001) but not phase (F(4155) < 0.27,p > 0.611), gain (F(4155) < 0.61,p > 0.440), or normalized gain (F(4155) < 0.85,p > 0.359) parameters. The Bland–Altman 95% LOA measuring the concurrent validity, trended to narrow as recording duration increased (60 s: < ±0.4, 120 s: < ±0.3, 180 s  < ±0.3, 240 s: < ±0.1). The validity of the 180 and 240 s recordings further increased when physiological covariates were included within regression models.Significance. Future studies examining autoregulation should seek to have participants perform 300 s of squat-stand maneuvers. However, valid and reliable TFA estimates can be drawn from 240 s or 180 s recordings if physiological covariates are controlled.
Schottky barrier heights in two-dimensional field-effect transistors: from theory to experiment
Authors: Wang Yangyang , Liu Shiqi , Li Qiuhui , Quhe Ruge , Yang Chen , Guo Ying , Zhang Xiuying , Pan Yuanyuan , Li Jingzhen , Zhang Han , Xu Lin , Shi Bowen , Tang Hao , Li Ying , Yang Jinbo , Zhang Zhiyong , Xiao Lin , Pan Feng , Lu Jing
Published: March 2021

Over the past decade, two-dimensional semiconductors (2DSCs) have aroused wide interest due to their extraordinary electronic, magnetic, optical, mechanical, and thermal properties, which hold potential in electronic, optoelectronic, thermoelectric applications, and so forth. The field-effect transistor (FET), a semiconductor gated with at least three terminals, is pervasively exploited as the device geometry for these applications. For lack of effective and stable substitutional doping techniques, direct metal contact is often used in 2DSC FETs to inject carriers. A Schottky barrier (SB) generally exists in the metal–2DSC junction, which significantly affects and even dominates the performance of most 2DSC FETs. Therefore, low SB or Ohmic contact is highly preferred for approaching the intrinsic characteristics of the 2DSC channel. In this review, we systematically introduce the recent progress made in theoretical prediction of the SB height (SBH) in the 2DSC FETs and the efforts made both in theory and experiments to achieve low SB contacts. From the comparison between the theoretical and experimentally observed SBHs, the emerging first-principles quantum transport simulation turns out to be the most powerful theoretical tool to calculate the SBH of a 2DSC FET. Finally, we conclude this review from the viewpoints of state-of-the-art electrode designs for 2DSC FETs.
Constructing quantum circuits with global gates
Authors: van de Wetering John
Published: March 2021

There are various gate sets that can be used to describe a quantum computation. A particularly popular gate set in the literature on quantum computing consists of arbitrary single-qubit gates and two-qubit CNOT gates. A CNOT gate is however not always the natural multi-qubit interaction that can be implemented on a given physical quantum computer, necessitating a compilation step that transforms these CNOT gates to the native gate set. An especially interesting case where compilation is necessary is for ion trap quantum computers, where the natural entangling operation can act on more than two qubits and can even act globally on all qubits at once. This calls for an entirely different approach to constructing efficient circuits. In this paper we study the problem of converting a given circuit that uses two-qubit gates to one that uses global gates. Our three main contributions are as follows. First, we find an efficient algorithm for transforming an arbitrary circuit consisting of Clifford gates and arbitrary phase gates into a circuit consisting of single-qubit gates and a number of global interactions proportional to the number of non-Clifford phases present in the original circuit. Second, we find a general strategy to transform a global gate that targets all qubits into one that targets only a subset of the qubits. This approach scales linearly with the number of qubits that are not targeted, in contrast to the exponential scaling reported in (Maslov and Nam 2018 New J. Phys.
20 033018). Third, we improve on the number of global gates required to synthesise an arbitrary n-qubit Clifford circuit from the 12n − 18 reported in (Maslov and Nam 2018 New J. Phys.
20 033018) to 6n − 8.
Ultimate quantum limit for amplification: a single atom in front of a mirror
Authors: Wiegand Emely , Wen Ping-Yi , Delsing Per , Hoi Io-Chun , Kockum Anton Frisk
Published: March 2021

We investigate three types of amplification processes for light fields coupling to an atom near the end of a one-dimensional (1D) semi-infinite waveguide. We consider two setups where a drive creates population inversion in the bare or dressed basis of a three-level atom and one setup where the amplification is due to higher-order processes in a driven two-level atom. In all cases, the end of the waveguide acts as a mirror for the light. We find that this enhances the amplification in two ways compared to the same setups in an open waveguide. Firstly, the mirror forces all output from the atom to travel in one direction instead of being split up into two output channels. Secondly, interference due to the mirror enables tuning of the ratio of relaxation rates for different transitions in the atom to increase population inversion. We quantify the enhancement in amplification due to these factors and show that it can be demonstrated for standard parameters in experiments with superconducting quantum circuits.
Exploring the fusion hindrance phenomenon: the case of 32,34S + 89Y
Authors: Gharaei R , Fuji A , Azadegan B , Mowlavi A A
Published: March 2021

The sub-barrier fusion data of 32,34S + 89Y colliding systems are analyzed using the coupled-channels (CC) calculations, including couplings to the low-lying 2+ and 3− states in reacting nuclei as well as mutual and multi-phonon excitations of these states, based on the proximity potential model. In this scheme, we focus upon the the effect of surface energy coefficient γ and also thermal properties of liquids and hot nuclei on the inner part of the nuclear potential and thus on the fusion cross sections at bombarding energies far below the Coulomb barrier. As expected, our primary calculations using the original proximity potential 1977 show that this model underestimates the measured fusion cross sections at the whole energy region. It is shown that the mentioned physical effects bring significant cross sections enhancements for both reactions. The indications of the fusion hindrance phenomenon in the fusion cross sections at energies far below the Coulomb barrier show up. The observed S factors for the above-mentioned systems develop a maximum at low energies which can also be predicted by the phenomenological extrapolations. Our results within the framework of the modified form of the proximity potential reveal that the calculated fusion cross sections, S factors, and logarithmic slopes for the two systems are in good agreement with the corresponding experimental data even at the lowest energies.
Properties of superdeformed bands in A < 100 mass region within the variable moment of inertia model
Authors: Devi Vidya , Matharu Jagjit Singh
Published: March 2021

The variable moment of inertia (VMI) model has been used to study the properties of superdeformed (SD) bands in A < 100 mass region. The experimental γ-ray (E

γ
) transitions energies are least square fitted to obtain the model parameters such as band head moment of inertia, (J
0), and stiffness constant, (C). The observed E

γ
transition energies obtained using the VMI formula are in excellent agreement with the experimental values. In the paper, we have studied the dynamic moment of inertia (J
(2)) and its variation with rotational frequency (ℏ
ω). We also studied the ΔI = 2 staggering phenomena in SD bands of 61Zn(SD), 62Zn(SD1), 80Sr(SD1), 81Sr(SD1), 82Sr(SD), 83Sr(SD), 84Zr(SD), 86Zr(SD1), 86Zr(SD4), 87Nb(SD2), 89Tc(SD) and 91Tc(SD) nuclei. The VMI model brings very comprehensive interpretation for spin assignment and to study the properties of SD bands in light mass region nuclei.
Cascaded semiconductor optical amplifiers-based all-optical OR logic gate
Authors: Kotb Amer , Zoiros Kyriakos E , Li Wei
Published: March 2021

We present a novel study of the ultrafast performance of an all-optical OR logic gate using two-cascaded semiconductor optical amplifiers (SOAs) at a data rate of 80 Gb s−1. The variation of the gate’s quality factor (Q-factor) against various key operating parameters, such as the continuous wave input power and wavelength, the operating data rate and the equivalent pseudorandom binary sequence length, is examined and assessed, taking into account the effects of SOAs amplified spontaneous emission and operating temperature to obtain results that are closer to reality. The simulation results indicate that the OR logic gate can be realized using the proposed two-cascaded SOAs scheme at 80 Gb s−1 with logical correctness and a Q-factor = 23.7, which is higher than that previously reported with other SOA-based schemes.
Precise Photometric Measurements from a 1903 Photographic Plate Using a Commercial Scanner
Authors: Cerny William , Chapman Alexis , Glusman Rowen , Kron Richard G. , Liang Yingyi , Lin Jason J. , Martinez Michael N. , Medina Elisabeth , Muratore Amanda , Ogonor Buduka , Sanchez Jorge A.
Published: March 2021

We demonstrate the feasibility of determining magnitudes of stars on archival photographic plates using a commercially available scanner. We describe one photometric approach that could serve as a useful example for other studies. In particular, we measure and calibrate stellar magnitudes from a 1903 photographic plate from the Yerkes Observatory collection, and demonstrate that the overall precision from our methods is better than 0.10 mag. Notably, these measurements are dominated by intrinsic plate noise, rather than noise introduced through the scanning/digitization process. The low expense of this approach expands the scientific potential to study variable stars in the archives of observatory plate collections. We use the serendipitous discovery of a candidate transient at photographic magnitude pg = 16.60 in the spiral galaxy NGC 7331 to illustrate our photometric methods. If this unknown source is a supernova, it would represent the fourth known supernova in NGC 7331.
Ab-initio calculations of bandgap tuning of In1–x
Ga
xy (y = N, P)alloys for optoelectronic applications
Authors: Rashid Muhammad , M Jamil , Q Mahmood , Ramay Shahid M , Mahmood A Asif , H M Ghaithan
Published: March 2021

The III–V alloys and doping to tune the bandgap for solar cells and other optoelectronic devices has remained a hot topic of research for the last few decades. In the present article, the bandgap tuning and its influence on optical properties of In1–x
Ga
x
N/P, where (x = 0.0, 0.25, 0.50, 0.75, and 1.0) alloys are comprehensively analyzed by density functional theory based on full-potential linearized augmented plane wave method (FP-LAPW) and modified Becke and Johnson potentials (TB-mBJ). The direct bandgaps turn from 0.7 eV to 3.44 eV, and 1.41 eV to 2.32 eV for In1–x
Ga
x
N/P alloys, which increases their potentials for optoelectronic devices. The optical properties are discussed such as dielectric constants, refraction, absorption, optical conductivity, and reflection. The light is polarized in the low energy region with minimum reflection. The absorption and optical conduction are maxima in the visible region, and they are shifted into the ultraviolet region by Ga doping. Moreover, static dielectric constant ε
1(0) is in line with the bandgap from Penn’s model.
Stationary response of colored noise excited vibro-impact system*
Authors: Wang Jian-Long , Leng Xiao-Lei , Liu Xian-Bin
Published: March 2021

The generalized cell mapping (GCM) method is used to obtain the stationary response of a single-degree-of-freedom. Vibro-impact system under a colored noise excitation. In order to show the advantage of the GCM method, the stochastic averaging method is also presented. Both of the two methods are tested through concrete examples and verified by the direct numerical simulation. It is shown that the GCM method can well predict the stationary response of this noise-perturbed system no matter whether the noise is wide-band or narrow-band, while the stochastic averaging method is valid only for the wide-band noise.
Search for topological defect of axionlike model with cesium atomic comagnetometer*
Authors: Yang Yucheng , Wu Teng , Zhang Jianwei , Guo Hong
Published: March 2021

Many terrestrial experiments have been designed to detect domain walls composed of axions or axionlike particles (ALPs), which are promising candidates of dark matter. When the domain wall crosses over the Earth, the pseudoscalar field of ALPs could couple to the atomic spins. Such exotic spin-dependent couplings can be searched for by monitoring the transient-in-time change of the atomic spin precession frequency in the presence of a magnetic field. We propose here a single-species cesium atomic comagnetometer, which measures the spin precession frequencies of atoms in different ground-state hyperfine levels, to eliminate the common-mode magnetic-field variations and search for the exotic non-magnetic couplings solely between protons and ALPs. With the single-species atomic comagnetometer, we experimentally rule out the possibility that the decay constant of the linear pseudoscalar couplings of ALPs to protons is f
p ≲ 3.71 × 107 GeV. The advanced system has the potential to constrain the constant to be f
p ≲ 10.7 × 109 GeV, promising to improve astrophysical constraint level by at least one order of magnitude. Our system could provide a sensitive detection method for the global network of optical magnetometers to search for exotic physics.
Measurement of differential cross sections of neutron-induced deuteron production reactions on carbon from 25 to 52 MeV *
Authors: Cui Zengqi , Jiang Haoyu , Sun Kang , Zhang Guohui , Fan Ruirui , Jiang Wei , Bai Huaiyong , Hu Yiwei , Liu Jie , Yi Han , Ning Changjun , Sun Zhijia , Tang Jingyu , An Qi , Bao Jie , Bao Yu , Cao Ping , Chen Haolei , Chen Qiping , Chen Yonghao , Chen Yukai , Chen Zhen , Feng Changqing , Gao Keqing , Gu Minhao , Han Changcai , Han Zijie , He Guozhu , He Yongcheng , Hong Yang , Huang Hanxiong , Huang Weiling , Huang Xiru , Ji Xiaolu , Ji Xuyang , Jiang Zhijie , Jing Hantao , Kang Ling , Kang Mingtao , Li Bo , Li Chao , Li Jiawen , Li Lun , Li Qiang , Li Xiao , Li Yang , Liu Rong , Liu Shubin , Liu Xingyan , Luan Guangyuan , Mu Qili , Qi Binbin , Ren Jie , Ren Zhizhou , Ruan Xichao , Song Zhaohui , Song Yingpeng , Sun Hong , Sun Xiaoyang , Tan Zhixin , Tang Hongqing , Tang Xinyi , Tian Binbin , Wang Lijiao , Wang Pengcheng , Wang Qi , Wang Taofeng , Wang Zhaohui , Wen Jie , Wen Zhongwei , Wu Qingbiao , Wu Xiaoguang , Wu Xuan , Xie Likun , Yang Yiwei , Yu Li , Yu Tao , Yu Yongji , Zhang Linhao , Zhang Qiwei , Zhang Xianpeng , Zhang Yuliang , Zhang Zhiyong , Zhao Yubin , Zhou Luping , Zhou Zuying , Zhu Danyang , Zhu Kejun , Zhu Peng
Published: March 2021

The angle-differential cross sections of neutron-induced deuteron production from carbon were measured at six neutron energies from 25 to 52 MeV relative to those of n-p elastic scattering at the China Spallation Neutron Source (CSNS) Back-n white neutron source. By employing the Δ
E-E telescopes of the Light-charged Particle Detector Array (LPDA) system at 15.1° to 55.0° in the laboratory system, ratios of the angle-differential cross sections of the 12C(n, xd) reactions to those of the n-p scattering were measured, and then, the angle-differential cross sections of the 12C(n, xd) reactions were obtained using the angle-differential cross sections of the n-p elastic scattering from the JENDL-4.0/HE-2015 library as the standard. The obtained results are compared with data from previous measurements, all of which are based on mono-energic neutrons, the evaluated data from the JENDL-4.0/ HE-2015 library and the ENDF-B/VIII.0 library, and those from theoretical calculations based on INCA code and Talys-1.9 code. Being the first white-neutron-source-based systematic measurement of the angle-differential cross sections of neutron-induced deuteron production reactions on carbon in several tens of MeV, the present work can provide a reference to the data library considering the lack of experimental data.
Strongly enhanced quadrupole deformation in a class of N≈ Z nuclei driven by large-scale clustering? *
Authors: Petkov P. , Müller-Gatermann C.
Published: March 2021

The formation of large size clusters, and/or their relative motion as a possible excitation mode, are suggested to be closely related to the origin of deformation in specific cases, namely the case of two doubly-magic clusters or two clusters with nearby characterization. New lifetime data in N = Z
76Sr and 80Zr leading to large B(E2) values are reproduced consistently and well within this approach, along with data for a few neighboring N

Z nuclei. These results are compared to previous studies of 32S and 20Ne and all of them support the ideas of the large-scale cluster approach.
A novel method to test particle ordering and final state alignment in helicity formalism *
Authors: Wang Mengzhen , Jiang Yi , Liu Yinrui , Qian Wenbin , Lyu Xiao-Rui , Zhang Liming
Published: March 2021

In this study, the non-trival effect of the selection of reference particles for decay angle definitions is demonstrated when constructing the partial-wave amplitude of multi-body decays using helicity formalism. This issue is often ignored in the standard use case of helicity formalism. A new technique is proposed to test the selection of the particle ordering, and it can also be used as a generalized method to calculate the rotation operators that are used for the final-state alignment between different decay chains. Moreover, numerical validations are performed to support the arguments and to verify the effectiveness of the proposed technique.
Hadronic coupling constants of the lowest hidden-charm pentaquark state, using QCD sum rules with rigorous quark-hadron duality *
Authors: Wang Zhigang , Wang Huijuan , Xin Qi
Published: March 2021

In this article, we illustrate how to calculate the hadronic coupling constants of the pentaquark states with QCD sum rules based on rigorous quark-hadron quality. We then study the hadronic coupling constants of the lowest diquark-diquark-antiquark type hidden-charm pentaquark state with spin-parity

in detail, and calculate the partial decay widths. The total width

is compatible with the experimental value

from the LHCb collaboration, and favors assigning the

to be the

pentaquark state with

. The hadronic coupling constants have the relation

, and favor the hadronic dressing mechanism. The

may have a diquark-diquark-antiquark type pentaquark core with the typical size of the

-type baryon states. The strong couplings to the meson-baryon pairs

lead to some pentaquark molecule components, and the

may spend a rather large time as the

molecular state.
Predicting the critical gradient of ITG turbulence in fusion plasmas
Authors: Pueschel M.J. , Li P.-Y. , Terry P.W.
Published: March 2021

The quasilinear mixing-length approach to efficient prediction of transport in fusion devices is improved to account for the ‘Dimits’ upshift between linear and nonlinear critical pressure gradients in zonal-flow-saturated turbulence regimes. This modification uses the frequency mismatch between modes interacting turbulently to track changes in saturation efficiency. Near criticality, energy is transferred exclusively to stable eigenmodes, rapidly increasing the efficacy of the nonlinearity. The modified quasilinear model is able to predict below-threshold turbulent ion-temperature-gradient-driven transport accurately and also yields significantly improved predictions for trapped-electron-mode transport.
Carbon Nanotubes as a Multifunctional additive and its Impact in Oil Based Mud System drilling Hydraulics
Authors: Okoro Emmanuel E. , Sanni Samuel E. , Obomanu Tamunotonjo , Okafor Ikechukwu S. , Emetere Moses E.
Published: March 2021

The drilling fluids should exhibit shear thinning characteristics to have less resistance at high shear rates. Nanoparticles can enhance the rheological properties of drilling fluids using different mechanisms. Nanomaterials are engineered materials with at least one dimension in the range of 1–100 nm. Carbon nanotubes were chosen in this study due to their unique physio-chemical properties, thus, a good candidate for smart oil based mud formulation. This study investigates the multifunctional ability of carbon nanotubes in oil based mud system and its impact on the drilling hydraulics. Application of carbon nanoparticles in literature have mostly been on water based mud systems and mostly at weight less than 2 g. Effect of carbon nanotubes on flow properties of oil based mud systems within the range of 1 to 3 g weight was analysed. The result shows that the carbon nanotubes improved the flow properties of the formulated oil based mud systems into an acceptable and desirable range required for optimal hole cleaning. The flow behaviour index (n) for the oil based mud systems for drilling hydraulics calculations were between zero and one, thus, they behaved like pseudo plastic fluids (Non-Newtonian fluids) both in the drill pipe and the annulus. It was also observed that, there was increase in the ratio of flow behaviour index to consistency index (n/K) and this will help reduce cuttings bed height in the wellbore.