bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spin transport through metal-dichalcogenides layers: a study from first-principles calculations
Authors: Devaraj Nayana , Tarafder Kartick 
Published: October 2020

Abstract
Spin transport through monolayer and trilayers of molybdenum dichalcogenides were studied considering Co as leads. Detailed investigations of the electronic structure of the Co/MoS2 interface and magnetic tri-junctions are carried out by using density functional theory calculations to understand transport behavior. The study revealed that new spin-polarized hybridized states appeared at the Fermi level due to the formation of Co/MoS2 interface that effectively acted as a spin filter and enhanced the spin injection efficiency of the systems. Spin-polarized current through the system as well as the magnetoresistance (MR) was estimated at different applied bias voltages. Large MR up to 78% was calculated for the trilayer MoS2 system at a relatively high applied bias voltage. The MR values are further improved by tuning the structure of the scattering region. A very large MR of 123% for MoS2/MoSe2/MoS2 trilayer at an applied bias 0.8 V was observed, which is much higher than the previously reported bias dependent MR values in similar systems.
Electric-field-induced spin spiral state in bilayer zigzag graphene nanoribbons
Authors: Prayitno Teguh Budi 
Published: October 2020

Abstract
We investigated the emergence of spin spiral ground state induced by the electric field in the bilayer zigzag graphene nanoribbons for the ferromagnetic edge states. To do that, we employed the generalized Bloch theorem to create flat spiral alignments for all the magnetic moments of carbon atoms at the edges within a constraint scheme approach. While the small ribbon width can preserve the ferromagnetic ground state, the large one shows the spiral ground state starting from a certain value of the electric field. We also pointed out that the spiral ground state is caused by the reduction of spin stiffness. In this case, the energy scale exhibits a subtle nature that can only be considered at the low temperature. For the last discussion, we also revealed that the spin spiral ground state appears more rapidly when the thickness increases. Therefore, we justify that the large ribbon width and large thickness can generate many spiral states induced by the electric field.
On the detection of surface spin freezing in iron oxide nanoparticles and its long-term evolution under ambient oxidation
Authors: Ghoshani M , Sánchez E H , Lee S S , Singh G , Yaacoub N , Peddis D , Mozaffari M , Binns C , De Toro J A , Normile P S 
Published: October 2020

Abstract
Exchange bias (EB) effects linked to surface spin freezing (SSF) are commonly found in iron oxide nanoparticles, while signatures of SSF in low-field temperature-dependent magnetization curves have been much less frequently reported. Here, we present magnetic properties of dense assemblies of similar-sized (∼8 nm diameter) particles synthesized by a magnetite (sample S1) and a maghemite (sample S2) method, and the influence of long-term (4 year) sample aging under ambient conditions on these properties. The size of the EB field of the different sample (fresh or aged) states is found to correlate with (a) whether a low-temperature hump feature signaling the SSF transition is detected in out-of-phase ac susceptibility or zero-field-cooled (ZFC) dc magnetization recorded at low field and with (b) the prominence of irreversibility between FC and ZFC curves recorded at high field. Sample S1 displays a lower magnetization than S2, and it is in S1 where the largest SSF effects are found. These effects are significantly weakened by aging but remain larger than the SSF effects in S2, where the influence of aging is considerably smaller. A non-saturating component due to spin disorder in S1 also weakens with aging, accompanied by, we infer, an increase in the superspin and the radius of the ordered nanoparticle cores. X-ray diffraction and Mössbauer spectroscopy provide indication of maghemite-like stoichiometry in both aged samples as well as thicker disordered particle shells in aged-S1 relative to aged-S2 (crystallographically-disordered and spin-disordered according to diffraction and Mössbauer, respectively). The pronounced diminution in SSF effects with aging in S1 is attributed to a (long-term) transition, caused by ambient oxidation, from magnetite-like to maghemite-like stoichiometry, and a concomitant softening of the spin-disordered shell anisotropy. We assess the impact of this anisotropy on the nature of the blocking of the nanoparticle superspins.
Template-assisted fabrication of Ag-nanoparticles@ZnO-nanorods array as recyclable 3D surface enhanced Raman scattering substrate for rapid detection of trace pesticides
Authors: Huo Dexian , Chen Bin , Li Mingtao , Meng Guowen , Lei Yong , Zhu Chuhong 
Published: October 2020

Abstract
We present a template-assisted fabrication method for a large-scale ordered arrays of ZnO nanorods (ZnO-NRs) modified with Ag nanoparticles (Ag-NPs), which possess high-density three-dimensional (3D) hot spots uniformly dispersed all over the substrate, being beneficial to ultrahigh sensitivity of surface enhanced Raman scattering (SERS) detection. These achieved Ag-NPs@ZnO-NRs arrays show high sensitivity, good spectral uniformity and reproducibility as substrates for SERS detection. Using the arrays, both dye molecules (rhodamine 6G, R6G) and organic pollutants like toxic pesticides (thiram and methyl parathion) are detected, with the detection limits of thiram and methyl parathion being 0.79 × 10−9 M and 1.51 × 10−8 M, respectively. In addition, the Ag-NPs@ZnO-NRs arrays have a self-cleaning function because the analyte molecules can be photocatalytic degraded using ultraviolet irradiation, showing that the 3D recyclable arrays have promising opportunities to be applied in rapid SERS-based detection of toxic organic pesticides.
Linac-integrated kV-cone beam CT polymer gel dosimetry
Authors: Jirasek A , Marshall J , Mantella N , Diaco N , Maynard E , Teke T , Hilts M 
Published: October 2020

Abstract
X-ray CT polymer gel dosimetry (PGD) remains a promising tool for three dimensional verification of high-dose treatment deliveries such as non-coplanar stereotactic irradiations. Recent demonstrations have shown a proof-of-principle application of linac-integrated cone beam CT-imaged (LI-CBCT) PGDs for 3D dose verification. LI-CBCT offers advantages over previous CT based PGD, including close to real-time imaging of the irradiated dosimeter, as well as the ability to maintain the dosimeter in the same physical location for irradiation and imaging, thereby eliminating spatial errors due to dosimeter re-positioning for read-out that may occur for other systems. However the dosimetric characteristics of a LI-CBCT PGD system remain to be established. The work herein determines the dosimetric properties and critical parameters needed to perform cone beam PGD. In particular, we show that imaging the dosimeter 20–30 min post irradiation offers excellent recovery of maximum polymerization yield (

>

90%), averaging with as few as 10 image averages can provide ∼90% gamma pass rates (3%, 3 mm) as compared to treatment planning, and that eliminating outlier averaging points can improve the precision and signal to noise ratio of resultant images. In summary, with appropriate methodology LI-CBCT PGD can provide dosimetric data capable of verification of complex high dose radiation deliveries in three dimensions and may find use in commissioning and validation of novel complex treatments.
Differentiation of pain levels by deploying various electroencephalogram synchronization features and a dynamic ensemble selection mechanism
Authors: Afrasiabi Somayeh , Boostani Reza , Masnadi-Shirazi Mohammad-Ali 
Published: October 2020

Abstract

Objective: The aim of this study was to measure pain intensity in an objective manner by analyzing electroencephalogram (EEG) signals. Although this problem has attracted the attention of researchers, increasing the resolution of this measurement by increasing the number of pain states significantly decreases the accuracy of pain level classification. Approach: To overcome this drawback, we adopt state-of-the-art synchronization schemes to measure the linear, nonlinear and generalized synchronization between different EEG channels. Thirty-two subjects executed the cold pressor task and experienced five defined levels of pain while their EEGs were recorded. Due to the large number of synchronization features from 34 channels, the most discriminative features were selected using the greedy overall relevancy method. The selected features were applied to a dynamic ensemble selection system. Main results: Our experiment provides 85.6% accuracy over the five classes, which significantly improves upon the results of past research. Moreover, we observed that the selected features belong to the channels placed over the ridge of the cortex, the area responsible for processing somatic sensation arising from nociceptive temperature. As expected, we noted that continuation of the painful stimulus for minutes engaged regions beyond the sensorimotor cortex (e.g. the prefrontal cortex). Significance: We conclude that the amount of synchronization between scalp EEG channels is an informative tool in revealing the pain sensation.
MOCVD growth of thick V-pit-free InGaN films on semi-relaxed InGaN substrates
Authors: White Ryan C , Khoury Michel , Wu Feng , Keller Stacia , Rozhavskaia Mariia , Sotta David , Nakamura Shuji , DenBaars Steven P 
Published: October 2020

Abstract
The MOCVD growth of InGaN:Si base layers on a semi-relaxed InGaN substrate, where growth is generally difficult due to the presence of V-pits, is examined. These V-pits can propagate through the crystal, causing severe morphological degradation and significantly reducing material quality for device use. Such V-pits may also be a source of leakage current if they extend from the substrate through p-n junction. A wide range of InGaN growth conditions and their impact on V-pit formation and density are investigated. The use of thin GaN interlayers, carrier gas selection, and V/III ratio are found play a critical role in managing V-pit quantity and size. Finally, high temperature GaN interlayers are implemented, fully eliminating V-pit formation in 1200 nm thick InGaN base layers grown coherently on semi-relaxed InGaN substrates.
Predicting task performance from biomarkers of mental fatigue in global brain activity
Authors: Yao Lin , Baker Jonathan L , Schiff Nicholas D , Purpura Keith P , Shoaran Mahsa 
Published: October 2020

Abstract

Objective. Detection and early prediction of mental fatigue (i.e. shifts in vigilance), could be used to adapt neuromodulation strategies to effectively treat patients suffering from brain injury and other indications with prominent chronic mental fatigue. Approach. In this study, we analyzed electrocorticography (ECoG) signals chronically recorded from two healthy non-human primates (NHP) as they performed a sustained attention task over extended periods of time. We employed a set of spectrotemporal and connectivity biomarkers of the ECoG signals to identify periods of mental fatigue and a gradient boosting classifier to predict performance, up to several seconds prior to the behavioral response. Main results. Wavelet entropy and the instantaneous amplitude and frequency were among the best single features across sessions in both NHPs. The classification performance using higher order spectral-temporal (HOST) features was significantly higher than that of conventional spectral power features in both NHPs. Across the 99 sessions analyzed, average F1 scores of 77.5% ± 8.2% and 91.2% ± 3.6%, and accuracy of 79.5% ± 8.9% and 87.6% ± 3.9% for the classifier were obtained for each animal, respectively. Significance. Our results here demonstrate the feasibility of predicting performance and detecting periods of mental fatigue by analyzing ECoG signals, and that this general approach, in principle, could be used for closed-loop control of neuromodulation strategies.
Q-PINE: A quick to implant peripheral intraneural electrode
Authors: Strauss Ivo , Niederhoffer Thomas , Giannotti Alice , Panarese Adele M , Bernini Fabio , Gabisonia Khatia , Ottaviani Matteo M , Petrini Francesco M , Recchia Fabio A , Raspopovic Stanisa , Micera Silvestro 
Published: October 2020

Abstract

Objective. The implantation of intraneural electrodes in amputees has been observed to be effective in providing subjects with sensory feedback. However, this implantation is challenging and time consuming. Surgeons must be especially trained to execute the implantation. Therefore, we aimed at developing a novel peripheral intraneural electrode and insertion mechanism, which could drastically reduce the overall implantation time while achieving a high neural selectivity. Approach. A new insertion method based on hollow microneedles was developed to realize the prompt and effective simultaneous implantation of up to 14 active sites in a transversal manner. Each needle guided two Pt/Ir microwires through the nervous tissue. After the insertion, the microneedles were released, leaving behind the microwires. Each microwire had one active site, which was coated with poly-3,4-ethylenedioxythiophene (PEDOT) to enhance the electrochemical properties. The active sites were characterized by evaluating the impedance, charge storage capacity, and maximum injectable charge. Twelve quick to implant peripheral intraneural electrodes (Q-PINEs) were implanted in four pig sciatic nerves to evaluate the implantation time and neural selectivity. We compared the stimulation of the sciatic nerve with that of its branches. Main results. The average surgical access time was 23 min. The insertion time for 12 electrodes was 6.7 min (std. ±1.6 min). The overall implantation time was reduced by 40.3 min compared to the previously reported values. The Q-PINE system demonstrated a satisfactory performance during in vitro and in vivo characterization. The electrochemical results showed that the PEDOT coating successfully increased the electrochemical parameters of the active sites. Significance. With an average impedance of 1.7 kΩ, a maximum charge level of 76.2 nC could be achieved per active site. EMG recruitment curves showed that 46% of the active sites exhibited selective stimulation of four out of six muscles. The histological analysis indicated that the microwires successfully penetrated the nerve and single fascicles.
Decoding network-mediated retinal response to electrical stimulation: implications for fidelity of prosthetic vision
Authors: Ho Elton , Shmakov Alex , Palanker Daniel 
Published: October 2020

Abstract

Objective. Patients with photovoltaic subretinal implant PRIMA demonstrated letter acuity ∼0.1 logMAR worse than sampling limit for 100 μm pixels (1.3 logMAR) and performed slower than healthy subjects tested with equivalently pixelated images. To explore the underlying differences between natural and prosthetic vision, we compare the fidelity of retinal response to visual and subretinal electrical stimulation through single-cell modeling and ensemble decoding. Approach. Responses of retinal ganglion cells (RGCs) to optical or electrical white noise stimulation in healthy and degenerate rat retinas were recorded via multi-electrode array. Each RGC was fit with linear–nonlinear and convolutional neural network models. To characterize RGC noise, we compared statistics of spike-triggered averages (STAs) in RGCs responding to electrical or visual stimulation of healthy and degenerate retinas. At the population level, we constructed a linear decoder to determine the accuracy of the ensemble of RGCs on N-way discrimination tasks. Main results. Although computational models can match natural visual responses well (correlation ∼0.6), they fit significantly worse to spike timings elicited by electrical stimulation of the healthy retina (correlation ∼0.15). In the degenerate retina, response to electrical stimulation is equally bad. The signal-to-noise ratio of electrical STAs in degenerate retinas matched that of the natural responses when 78 ± 6.5% of the spikes were replaced with random timing. However, the noise in RGC responses contributed minimally to errors in ensemble decoding. The determining factor in accuracy of decoding was the number of responding cells. To compensate for fewer responding cells under electrical stimulation than in natural vision, more presentations of the same stimulus are required to deliver sufficient information for image decoding. Significance. Slower-than-natural pattern identification by patients with the PRIMA implant may be explained by the lower number of electrically activated cells than in natural vision, which is compensated by a larger number of the stimulus presentations.
Quantum interference via nonradiative transitions between energy levels of atoms in one-dimensional photonic crystals
Authors: Kh Gainutdinov R , Garifullin A I , Khamadeev M A , Kh Salakhov M 
Published: October 2020

Abstract
The self-energy correction to the mass of an atomic electron placed into a void of the photonic crystal medium is investigated. In this study the one-dimensional photonic crystal made from gallium arsenide and vacuum layers is considered. We show that the electron mass change gives rise not only to the shifts of the atomic energies but also to the nonradiative transitions between atomic levels. These transitions add new channels to a decay of an atomic state that leads to a quantum interference between these channels.
FTIR spectroscopic study of enthalpy differences of conformers of substituted ethanes in PVB plasticized by PEGs
Authors: Kamalova D I , Abdrazakova L R 
Published: October 2020

Abstract
In present investigation, the enthalpy differences of conformers for substituted ethanes in PVB/PEG 200, PVB/PEG 400 and PVB/PEG600 blended systems with the compositions of 80:20, 70:30, 60:40 and 50:50 have been determined by FTIR spectroscopy. The influence of the plasticizer content and molecular weight of poly(ethylene glycol) on the enthalpy difference of the conformers has been studied.
Partially coherent photon echo in the presence of pulsed and static magnetic fields
Authors: Lisin Valery , Shegeda Anatoly , Samartsev Vitaly 
Published: October 2020

Abstract
The theory of a partially coherent photon echo in a static magnetic field at the presence of a pulsed magnetic field, causing oscillations of the echo intensity, is constructed. It is shown that the coherence time can be found by the dependence of the echo intensity on the laser frequency. The theory is compared with the experiment in LuLiF4:Er3+ (transition 4I15/2 -4F9/2) and in YLiF4:Er3+ at the same transition.
Localized waves in the nonlinear rhombic waveguide array
Authors: Maimistov A I , Lyashko E I , Elyutin E O 
Published: October 2020

Abstract
Solitary electromagnetic waves propagating along the waveguides forming a rhombic one-dimensional lattice are considered. Two waveguides that are part of the unit cell are assumed to be made of an optical linear material, while the third waveguide from the same array is composed of material with the cubic nonlinearity. The equations of the coupled waves spreading in each waveguide are solved under some approximation. These solutions represent the breather like solitary waves, which are akin to three component soliton.
Two-color vortex solitons in the quadratic nonlinear waveguide
Authors: Sazonov S V 
Published: October 2020

Abstract
Based on the averaged Lagrangian method, the possibility of forming a spatiotemporal soliton of the type of a two-frequency optical vortex in a waveguide with quadratic nonlinearity is investigated. In the approximation of the diffraction limit the corresponding analytical solutions are obtained.
Digital Assistance in the Maintenance of Offshore Wind Parks
Authors: Eggert Martin , Stepputat Marten , Fluegge Wilko 
Published: October 2020

Abstract
Harsh environmental conditions, time pressure due to tightly calculated maintenance windows, complex technical systems and high quality standards determine the working environment for the maintenance and repair of offshore wind farms. Despite good qualifications and diverse training courses, maintenance technicians are reliant on information from manuals and checklists when performing their tasks and must document their work results in protocols. Both the supply of information and the data acquisition show a multitude of media disruptions. Hence, the processes on site and in the postprocessing are carried out slowly and uncertainly. The assistance system presented is intended to contribute to a consistently digital information flow and to support the technicians in a task-specific manner. Augmented Reality (AR) offers a way of presenting information and interacting with the assistance system during work execution. Using the example of the maintenance of crane systems used in a variety of ways in offshore wind farms, this article shows which potential can be tapped through digital assistance systems and AR applications.
Friction coefficients for steel to steel contact surfaces in air and seawater
Authors: Pijpers R.J.M. , Slot H.M. 
Published: October 2020

Abstract
Through a series of laboratory friction tests on small scale specimens an understanding of the physical behaviour is gained. The test program of the friction tests contained 12 test specimen variants, with a combination of dry air and seawater environment and various surface conditions and contact pressures.
Comparison of Weather Window Statistics and Time Series Based Methods Considering Risk Measures
Authors: Lübsen J , Wolken-Möhlmann G 
Published: October 2020

Abstract
Offshore projects, like the installation of offshore wind farms, consist of a number of different and often weather dependent activities. These tasks and their relations are defined in project schedules, which have to be assessed for weather effects before the project realization. Here, often Weather Window Statistics are used to calculate probable weather delay times using relative frequencies of weather windows. Another possible approach is the Weather Time Series Scheduling (WaTSS) method which combines the given project schedule, weather restrictions and historical weather time series data for several decades. The aim of this paper is a comparison of the two approaches especially when it comes to risk analysis for project schedules using percentile values or related risk measures. The same ERA5 model data is used both as basis for the Weather Window Statistics and the WaTSS method. We calculate weather downtimes for each task, as well as for the total project, and apply the risk measures Value at Risk (VaR), Conditional Value at Risk (cVaR) and Upper Partial Moments (UPM). This is followed by an analysis of the results from Weather Window Statistics and the WaTSS method considering their applicability and consistence. We obtain that risk measurement for project schedules under use of Weather Window Statistics is not always practicable because certain risk values tend to overestimation. WaTSS method provides project adjusted modeling and leads to more realistic risk measurement for complex project schedules.