bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonlinear and thermo-optical characterisation of bare imidazolium ionic liquids
Authors: Ferreira Vinícius C , Marin Graciane , Dupont Jairton , Correia Ricardo R B 
Published: November 2020

Abstract
Nonlinear optical (NLO) and thermo-optical properties of two pure ionic liquids, BMIOMe.NTf2 and BMIOMe.N(CN)2, were examined in this study. This was the first nonlinear refractive index determination of a pristine ionic liquid by a standard self-refraction experiment. The NLO characterisations were performed using Z-scan and EZ-scan techniques in the thermally managed approach, with a mode-locked femtosecond laser source. Thermal properties were analysed concomitantly, and the thermo-optical coefficient, thermal characteristic time, and lens strength were characterised. These results define the parameters to be adopted in the method of nanoparticles formation by laser ablation in an ionic liquid solution and indicate that BMIOMe.NTf2 is a prominent material to be engineered for photonics applications.
Enhanced valleytronic properties in germanene by direct proximity to heavy metal layer
Authors: Qu Jinfeng , Luo Chaobo , Peng Xiangyang , Chen Guoxiang , Guo Shaoli , Zhong Jianxin 
Published: November 2020

Abstract
Germanene, though with Dirac valleys, is not deemed as a good valleytronic material due to its minute band gap, negligible spin–orbit coupling and spatial inversion symmetry. In comparison of interfacing germanene with MoS2, we proposed that forming heterostructure with Tl2S, an anti-MoS2 material with two outer heavy metal layers, could be more effective in raising spin–orbit coupling and band gap in germanene due to the direct Ge-metal contact. By carrying out first-principles calculations, we studied the valleytronic properties of germanene enhanced by monolayer Tl2S. It is found that the Ge–Tl direct interaction is strong to a proper extent so that the valleys of germanene still persist and simultaneously the valley gap is drastically increased from 23 to 370 meV. The valley spin splitting, being zero in pristine germanene, become 45 meV, which is opposite at inequivalent valleys owing to the time reversal symmetry. The inversion symmetry of germanene is broken by Tl2S, resulting in large Berry curvature near the valleys and hence laying the ground for Berry phase physics in germanene, e.g., valley spin Hall effect and valley–spin locking, as revealed in our study. The calculations found a perfect valley-selective circular dichroism, by which the valley and spin degrees of freedom can be manipulated selectively and correlatively.
Mn substitution effect on the local structure of La(Fe1−x
Mn
x
)AsO studied by temperature dependent x-ray absorption measurements
Authors: Hacisalihoglu M Y , Simonelli L , Marini C , Provino A , Martinelli A , Manfrinetti P , Putti M , Saini N L 
Published: November 2020

Abstract
The local structure of La(Fe1−x
Mn
x
)AsO has been investigated using temperature dependent Fe K-edge extended x-ray absorption fine structure (EXAFS) measurements. The EXAFS data reveal distinct behavior of Fe–As and Fe–Fe atomic displacements with a clear boundary between x ⩽ 0.02 and x > 0.02. The Fe–As bondlength shows a gradual thermal expansion while the Fe–Fe bond manifests a temperature dependent anomaly at ∼180 K for x > 0.02. It is interesting to find characteristically different nature of Fe–As and Fe–Fe bondlengths shown by the temperature dependent mean square relative displacements. Indeed, the Fe–As bond, stiffer than that of the Fe–Fe, gets softer for x ⩽ 0.02 and hardly shows any change for x > 0.02. On the other hand, Fe–Fe bond tends to be stiffer for x ⩽ 0.02 followed by a substantial softening for x > 0.02. Such a distinction has been seen also in the As K-edge x-ray absorption near edge structure, probing local geometry around As atom together with the valence electronic structure. The results suggest that local atomic displacements by Mn substitution inducing increased iron local magnetic moment that should be the main reason for its dramatic effect in iron-based superconductors.
Optical design of InGaN/GaN nanoLED arrays on a chip: toward: highly resolved illumination
Authors: Kluczyk-Korch K , Palazzo D , Waag A , Diéguez A , Prades J D , Di Carlo A , der Maur M Auf 
Published: November 2020

Abstract
The physical laws of diffraction limit the spatial resolution of optical systems. In contrary to most superresolution microscopy approaches used today, in our novel idea we are aiming to overcome this limit by developing a spatially resolved illumination source based on semiconductor nanoscale light emitting diode (nanoLED) arrays with individual pixel control. We present and discuss the results of optical simulations performed for such nanoLED emitter arrays and analyze the theoretical limits of this approach. As possible designs we study arrays of GaN nanofins and nanorods (obtained by etching nanofin arrays), with InGaN/GaN multi quantum wells embedded as active regions. We find that a suitable choice of the array dimensions leads to a reasonably directed light output and concentration of the optical power in the near field around an activated pixel. As a consequence, the spatial resolution for this type of microscopy should only be limited by the pixel pitch, and no longer by the optical diffraction. Realization of optimized nanoLED arrays has a potential to open new field of chip based superresolution microscopy, making super-high spatial resolution ubiquitously available.
Construction of Z-scheme Ag/In2S3/ZnO nanorods composite photocatalysts for degradation of 4-nitrophenol
Authors: Wei Junwei , Wei Shuoming , Chang Na , Wang Haitao , Zhang Jimei 
Published: November 2020

Abstract
Herein, Ag/In2S3/ZnO nanorods (NRs) composite photocatalysts were successfully prepared via simple methods. Significantly, hydroxyl radical active substances were found in the electron spin resonance tests of In2S3/ZnO NRs and Ag/In2S3/ZnO NRs, which indicates that the oxidation reaction that oxidizes water or hydroxide ions into hydroxyl radicals occurs on the valence band of ZnO NRs. It suggests that Z-scheme heterojunction was successfully constructed. In the photocatalytic experiments of degrading 4-nitrophenol (PNP), the Ag/In2S3/ZnO NRs composite exhibits higher photocatalytic activity than ZnO NRs, In2S3, Ag/ZnO NRs and In2S3/ZnO NRs. The characteristic peak of PNP disappears completely in 50 min. The enhanced photocatalytic performance can be attributed to the formation of Z-scheme heterojunction between ZnO NRs and In2S3. In addition, local surface plasmon resonance of Ag and Schottky junction formed between Ag and In2S3 also promote the photocatalytic activity.
High-performance mid-infrared photodetection based on Bi2Se3 maze and free-standing nanoplates
Authors: Luo Shi , Li JiaLu , Sun Tai , Liu Xiangzhi , Wei Dacheng , Zhou Dahua , Shen Jun , Wei Dapeng 
Published: November 2020

Abstract
The pursuit of optoelectronic devices operating in mid-infrared regime is driven by both fundamental interests and commercial applications. The narrow bandgap (0.3 eV) of layered Bi2Se3 makes it a promising material for mid-infrared photodetection. However, the weak absorption of mid-infrared optical power and high dark current level restrict its performance. Here, a supply-control technique is applied to modulate the growth mode of Bi2Se3 crystal, and Bi2Se3 crystals with various morphologies are obtained. The nanoplates pattern transits from maze to freestanding when source mass was tuned. Due to the strong infrared absorption and photoelectric conversion efficiency of vertical Bi2Se3 nanoplates, the as-prepared vertical Bi2Se3 nanoplates/Si heterojunction shows excellent photoresponse and extremely low dark current. Among these devices based on different Bi2Se3 morphologies, freestanding nanoplates show the optimal mid-infrared characteristics, namely a photo-to-dark ratio of 2.0 × 104, a dark current of 0.21 pA, a response time of 23 ms, a specific detectivity of 6.1 × 1010 Jones (calculated) and 1.2 × 1010 Jones (measured) under 2.7 μm illumination and at room temperature. Notably, the specific detectivity of our devices are comparable to commercial InGaAs photodetectors. With the tunable- morphology growing technique and excellent photoresponding characteristics, Bi2Se3 nanomaterials are worth attention in optoelectronic field.
Growth dynamics and compositional structure in periodic InAsSb nanowire arrays on Si (111) grown by selective area molecular beam epitaxy
Authors: Ruhstorfer Daniel , Lang Armin , Matich Sonja , Döblinger Markus , Riedl Hubert , Finley Jonathan J , Koblmüller Gregor 
Published: November 2020

Abstract
We report a comprehensive study of the growth dynamics in highly periodic, composition tunable InAsSb nanowire (NW) arrays using catalyst-free selective area molecular beam epitaxy. Employing periodically patterned SiO2-masks on Si (111) with various mask opening sizes (20–150 nm) and pitches (0.25–2 μm), high NW yield of >90% (irrespective of the InAsSb alloy composition) is realized by the creation of an As-terminated 1 × 1-Si(111) surface prior to NW nucleation. While the NW aspect ratio decreases continually with increasing Sb content (x
Sb from 0% to 30%), we find a remarkable dependence of the aspect ratio on the mask opening size yielding up to ∼8-fold increase for openings decreasing from 150 to 20 nm. The effects of the interwire separation (pitch) on the NW aspect ratio are strongest for pure InAs NWs and gradually vanish for increasing Sb content, suggesting that growth of InAsSb NW arrays is governed by an In surface diffusion limited regime even for the smallest investigated pitches. Compositional analysis using high-resolution x-ray diffraction reveals a substantial impact of the pitch on the alloy composition in homogeneous InAsSb NW arrays, leading to much larger x
Sb as the pitch increases due to decreasing competition for Sb adatoms. Scanning transmission electron microscopy and associated energy-dispersive x-ray spectroscopy performed on the cross-sections of individual NWs reveal an interesting growth-axis dependent core–shell like structure with a discontinuous few-nm thick Sb-deficient coaxial boundary layer and six Sb-deficient corner bands. Further analysis evidences the presence of a nanoscale facet at the truncation of the (111)B growth front and {1-10} sidewall surfaces that is found responsible for the formation of the characteristic core–shell structure.
Denoising non-steady state dynamic PET data using a feed-forward neural network
Authors: Angelis G I , Fuller O K , Gillam J E , Meikle S R 
Published: November 2020

Abstract
The quality of reconstructed dynamic PET images, as well as the statistical reliability of the estimated pharmacokinetic parameters is often compromised by high levels of statistical noise, particularly at the voxel level. Many denoising strategies have been proposed, both in the temporal and spatial domain, which substantially improve the signal to noise ratio of the reconstructed dynamic images. However, although most filtering approaches are fairly successful in reducing the spatio-temporal inter-voxel variability, they may also average out or completely eradicate the critically important temporal signature of a transient neurotransmitter activation response that may be present in a non-steady state dynamic PET study. In this work, we explore an approach towards temporal denoising of non-steady state dynamic PET images using an artificial neural network, which was trained to identify the temporal profile of a time-activity curve, while preserving any potential activation response. We evaluated the performance of a feed-forward perceptron neural network to improve the signal to noise ratio of dynamic [11C]raclopride activation studies and compared it with the widely used highly constrained back projection (HYPR) filter. Results on both simulated Geant4 Application for Tomographic Emission data of a realistic rat brain phantom and experimental animal data of a freely moving animal study showed that the proposed neural network can efficiently improve the noise characteristics of dynamic data in the temporal domain, while it can lead to a more reliable estimation of voxel-wise activation response in target region. In addition, improvements in signal-to-noise ratio achieved by denoising the dynamic data using the proposed neural network led to improved accuracy and precision of the estimated model parameters of the lp-ntPET model, compared to the HYPR filter. The performance of the proposed denoising approach strongly depends on the amount of noise in the dynamic PET data, with higher noise leading to substantially higher variability in the estimated parameters of the activation response. Overall, the feed-forward network led to a similar performance as the HYPR filter in terms of spatial denoising, but led to notable improvements in terms of temporal denoising, which in turn improved the estimation activation parameters.
Correlation between maximal radial muscle displacement and stiffness in gastrocnemius muscle
Authors: Labata-Lezaun Noé , López-de-Celis Carlos , Llurda-Almuzara Luis , González-Rueda Vanessa , Cadellans-Arróniz Aida , Pérez-Bellmunt Albert 
Published: November 2020

Abstract

Objective: Tensiomyography (TMG) and myotonometry (MMT) are two novel technologies that measure neuromuscular properties. These two devices measure the stiffness of the soft tissue as well as other variables. The aim of this study is to analyze if there is any correlation between maximal radial displacement (Dm) and Stiffness in the medial and lateral gastrocnemius muscles. Approach: An observational study was carried out in both of the limbs of 154 young adults (n = 154). The TMG and MMT neuromuscular response was measured in gastrocnemius medial and lateral muscles. Correlation coefficients were calculated to observe if there were any relationships between Dm and Stiffness. Differences between the dominant and the non-dominant sides and gender were assessed. Main results: Negative correlations between Dm versus Stiffness were found for the lateral (r = −0.278 and rho = −0.248) and medial gastrocnemius (r = −0.207 and rho = −0.163) in both dominant and non-dominant limbs respectively. Significance: A weak correlation between Dm and Stiffness may indicate that they assess different aspects of neuromuscular function. The MMT and TMG are independent tools, and their values cannot be extrapolated when assessing muscular stiffness. There might be some other factors that influence in this relationship; therefore, more studies are needed in order to better understand the correlation.
Effect of temperature on morphologies and optical study of ZnO thin films deposited by aerosol assisted chemical vapor deposition technique
Authors: Palve Anil M , Garje Shivram S 
Published: November 2020

Abstract
ZnO thin films were deposited on glass substrates by an aerosol assisted chemical vapor deposition method using Zn(II) semicarbazone complexes, ZnCl2(LH)2, (where LH = semicarbazones of cinnamaldehyde, 4-flouroacetophenone, benzaldehyde and 4-chlorobenzaldehyde) as precursors. X-ray diffraction patterns of as-deposited thin films show the formation of hexagonal ZnO (ICDD: 79-2205) at all the deposition temperatures, i.e. 350 °C, 400 °C and 450 °C. The UV–visible spectra show that the thin films are transparent in the visible range. The presence of the high intensity phonon mode at 438 cm−1 in the Raman spectra indicates the wurtzite phase of the ZnO thin films. Scanning electron microscopy images reveal the formation of different morphologies, hexagonal plates, nearly spherical particles and tetrapods at different temperatures. The roughnesses of the thin films were determined using atomic force microscopy.
SESAM-based mode-locked vortex Ti:sapphire laser using spot-defect spatial filter for intra-cavity mode selection
Authors: Tang Fanchun , Shi Biran , Zhang Quan , Zhou Changhe , Bu Yang , Li Jianlang 
Published: November 2020

Abstract
In virtue of the significance of ultrashort vortex pulses, a mode-locked LG01-mode vortex Ti:sapphire laser is first realized. In the study, an intra-cavity spot-defect spatial filter was used to suppress the TEM00 mode’s oscillation and a semiconductor saturable absorber mirror was used as the mode-locked device. As a result, the mode-locked laser emitted LG01-mode vortex pulses of 186 ps at 804.4 nm with a repetition rate of 78.95 MHz and a maximum average output power of 176 mW. The phase of the LG01 mode was measured by a Mach–Zehnder interferometer and both right- and left-handed helical wavefronts were obtained.
Positivity in electron-positron scattering: testing the axiomatic quantum field theory principles and probing the existence of UV states *
Authors: Fuks Benjamin , Liu Yiming , Zhang Cen , Zhou Shuang-Yong 
Published: November 2020

Abstract
We consider the positivity bounds on dimension-8 four-electron operators and study two related phenomenological aspects at future lepton colliders. First, if positivity is violated, probing such violations will revolutionize our understanding of the fundamental pillars of quantum field theory and the S-matrix theory. We observe that positivity violation at scales of 1-10 TeV can potentially be probed at future lepton colliders even if one assumes that dimension-6 operators are also present. Second, the positive nature of the dimension-8 parameter space often allows us to either directly infer the existence of UV-scale particles together with their quantum numbers or exclude them up to certain scales in a model-independent way. In particular, dimension-8 positivity plays an important role in the test of the Standard Model. If no deviations from the Standard Model are observed, it allows for simultaneous exclusion limits on all kinds of potential UV-complete models. Unlike the dimension-6 case, these limits apply regardless of the UV model setup and cannot be removed by possible cancellations among various UV contributions. This thus consists of a novel and universal test to confirm the Standard Model. We demonstrate with realistic examples how all the previously mentioned possibilities, including the test of positivity violation, can be achieved. Hence, we provide an important motivation for studying dimension-8 operators more comprehensively.
Impact of LHCb 13 TeV W and Z pseudo-data on the parton distribution functions *
Authors: Deng Qilin , Han Qundong , Yin Hang , Dulat Sayipjamal , Hou Tie-Jiun , Yuan C.–P. 
Published: November 2020

Abstract
We study the potential of the LHCb 13 TeV single W
± and Z boson pseudo-data for constraining the parton distribution functions (PDFs) of the proton. As an example, we demonstrate the sensitivity of the LHCb 13 TeV data, collected with integrated luminosities of 5

and 300

, to reducing the PDF uncertainty bands of the CT14HERA2 PDFs, using the error PDF updating package EPUMP. The sensitivities of various experimental observables are compared. Generally, sizable reductions in PDF uncertainties can be observed in the 300

data sample, particularly in the small-x region. The double-differential cross section measurement of Z boson p
T and rapidity can greatly reduce the uncertainty bands of u and d quarks in almost the whole x range, as compared to various single observable measurements.
Solar image deconvolution by generative adversarial network
Authors: Xu Long , Sun Wen-Qing , Yan Yi-Hua , Zhang Wei-Qiang 
Published: November 2020

Abstract
With aperture synthesis (AS) technique, a number of small antennas can be assembled to form a large telescope whose spatial resolution is determined by the distance of two farthest antennas instead of the diameter of a single-dish antenna. In contrast from a direct imaging system, an AS telescope captures the Fourier coefficients of a spatial object, and then implement inverse Fourier transform to reconstruct the spatial image. Due to the limited number of antennas, the Fourier coefficients are extremely sparse in practice, resulting in a very blurry image. To remove/reduce blur, “CLEAN” deconvolution has been widely used in the literature. However, it was initially designed for a point source. For an extended source, like the Sun, its efficiency is unsatisfactory. In this study, a deep neural network, referring to Generative Adversarial Network (GAN), is proposed for solar image deconvolution. The experimental results demonstrate that the proposed model is markedly better than traditional CLEAN on solar images. The main purpose of this work is visual inspection instead of quantitative scientific computation. We believe that this will also help scientists to better understand solar phenomena with high quality images.
The effect of hydrodynamics alone on the subhalo population in a ΛCDM rich cluster sized dark matter halo
Authors: Jia Jun-Yi , Gao Liang , Qu Yan 
Published: November 2020

Abstract
We perform a set of non-radiative hydro-dynamical (NHD) simulations of a rich cluster sized dark matter halo from the Phoenix Project with three different numerical resolutions, to investigate the effect of hydrodynamics alone on the subhalo population in the halo. Compared to dark matter only (DMO) simulations of the same halo, subhaloes are less abundant for relatively massive subhaloes (M
sub > 2.5 × 109
h
−1
M
⊙, or V
max > 70 km s−1) but more abundant for less massive subhaloes in the NHD simulations. This results in different shapes in the subhalo mass/V
max function in two different sets of simulations. At given subhalo mass, the subhaloes less massive than 1010
h
−1
M
⊙ have larger V
max in the NHD than DMO simulations, while V
max is similar for the subhaloes more massive than the mass value. This is mainly because the progenitors of present day low mass subhaloes have larger concentration parameters in the NHD than DMO simulations. The survival number fraction of the accreted low mass progenitors of the main halo at redshift 2 is about 50 percent higher in the NHD than DMO simulations.
Accretion flow properties of XTE J1118+480 during its 2005 outburst
Authors: Debnath Dipak , Chatterjee Debjit , Jana Arghajit , Chakrabarti Sandip K. , Chatterjee Kaushik 
Published: November 2020

Abstract
We study spectral and temporal properties of Galactic short orbital period transient black hole XTE J1118+480 during its 2005 outburst using archival data of RXTE PCA and HEXTE instruments in the combined energy range of 3 – 100 keV. Spectral analysis with the physical two component advective flow (TCAF) model allows us to understand the accretion flow properties of the source. We found that this outburst of XTE J1118+480 is an unconventional outburst as the source was only in the hard state (HS). Our spectral analysis suggests that during the entire outburst, the source was highly dominated by the low angular momentum sub-Keplerian halo rate. Since the source was active in radio throughout the outburst, we make an effort to estimate X-ray contribution of jets to total observed X-ray emissions from the spectral analysis with the TCAF model. The total X-ray intensity shows a similar nature of evolution as that of radio and jet X-ray fluxes. This allowed us to define this ‘outburst’ also as a jet dominated ‘outburst’. Total X-ray flux is also found to subside when jet activity disappears. Our detailed spectral analysis also indicated that although the source was only in the HS during the outburst, in the late declining phase the spectrum became slightly softer due to the slow rise in the Keplerian disk rate.