bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of landscape-level factors on the abundance and diversity of diapausing wetland (lagoon) microinvertebrates
Authors: Growns I. , Frost L. , Hunter J. T. , Mika S.
Published: November 2020

Temporary wetlands are some of the most productive ecosystems available to aquatic and terrestrial organisms. Invertebrates play a critical role in wetlands linking aquatic and terrestrial carbon sources to higher trophic levels such as fish and waterbirds. We assessed the role of large-scale landscape variables (including altitude, longitude and latitude) and wetland size and on the egg-bank structure in 15 wetlands (lagoons) in the North Tableland region of New South Wales. We used microcosms to inundate dry soil from the lagoons and identified the resulting emerged microinvertebrate assemblages. We identified nine microinvertebrate taxa and each lagoon had its own unique microinvertebrate assemblage. The environmental variables did not play a role in determining the assemblages, which emerged from the egg banks of the lagoons, suggesting that each individual lagoon would need to be managed separately for conservation purposes.
Cross-linguistic influence of L2 on L1 in late Chinese-English bilinguals
Authors: Liu Ying , Qi Ruying , Di Biase Bruno
Published: November 2020

Cross-linguistic influence studies usually investigate how the bilingual’s first language (L1) influences the acquisition and use of their second language (L2) within the L2 context. This study, by contrast, investigates how the bilingual’s L2 may influence their L1 within the L1 environment, specifically whether the L2 affects L1 performance in an L1 environment in Chinese (L1)-English (L2) late bilinguals, in the domain of subject realisation. Typologically, Chinese allows pronominal subjects to be optionally null under certain discourse-pragmatic conditions whereas English requires obligatory pronominal subjects under most circumstances. To examine possible L2 effects, 15 Chinese-English bilinguals (Experimental) and 15 Chinese monolinguals (Control) participated in Chinese narrative tasks. Results show that bilingual participants produce significantly lower percentages of null subjects than the control group, indicating that bilinguals prefer overt subjects over null subjects in their L1 Chinese utterances under the influence of L2 English syntactic patterns.
A Fully Symmetrical Quantum Key Distribution System Capable of Preparing and Measuring Quantum States*
Authors: Dou Tianqi , Wang Jipeng , Li Zhenhua , Qu Wenxiu , Yang Shunyu , Sun Zhongqi , Zhou Fen , Han Yanxin , Huang Yuqing , Ma Haiqiang
Published: November 2020

We propose a fully symmetrical QKD system that enables quantum states to be prepared and measured simultaneously without compromising system performance. Over a 25.6 km fiber channel, we demonstrate point-to-point QKD operations with asymmetric Mach–Zehnder interferometer modules. Two interference visibilities of above 99% indicate that the proposed system has excellent stability. Consequently, the scheme not only improves the feasibility of distributing secret keys, but also enables QKD closer to more practical applications.
Possible Candidates for Chirality in the Odd-Odd As Isotopes
Authors: Liu Chen , Wang Shouyu , Qi Bin , Jia Hui
Published: November 2020

The deformations and the corresponding configurations of the odd-odd As isotopes are investigated using the adiabatic and configuration-fixed constrained triaxial relativistic mean field (RMF) theory. Energy minima with triaxial deformations and high-j particle-hole configurations are obtained in 72,74,76,78,80As, where the chiral doublet bands are possible to appear. The existence of multiple chiral doublet (MχD) is demonstrated in 74,76,78As. Based on the calculated single-particle levels, we also find possible coexistence of chiral and pseudospin symmetries in the odd-odd As isotopes.
Universality of the Dynamic Characteristic Relationship of Electron Correlation in the Two-Photon Double Ionization Process of a Helium-Like System
Authors: Li Fei , Yang Yu-Jun , Chen Jing , Liu Xiao-Jun , Wei Zhi-Yi , Wang Bing-Bing
Published: November 2020

Universality of the dynamic characteristic relationship between the characteristic time t
c and the two-electron Coulomb interaction energy

V
¯

12

of the ground state in the two-photon double ionization process is investigated via changing the parameters of the two-electron atomic system and the corresponding laser conditions. The numerical results show that the product

t
c

V
¯

12

keeps constant around 4.1 in the cases of changing the nucleus charge, the electron charge, the electron mass, and changing simultaneously the nucleus charge and the electron charge. These results demonstrate that the dynamic characteristic relationship in the two-photon double ionization process is universal. This work sheds more light on the dynamic characteristic relationship in ultrafast processes and may find its application in measurements of attosecond pulses.
Semi-Ellipsoid Nanoarray for Angle-Independent Plasmonic Color Printing*
Authors: Xue Jiancai , Lin Limin , Zhou Zhang-Kai , Wang Xue-Hua
Published: November 2020

Employing a silver nano semi-ellipsoid nanoarray with high symmetry into applications in plasmonic color printing, we fulfill printing images with colors independent of observing angles. Also, by decreasing the period of a nano semi-ellipsoid array into deep-subwavelength scales, we obtain high reflectivity over 50%, promising high efficiency for imaging generations. A facile technique based on the transfer of anodized aluminum oxide template is developed to fabricate the silver nano semi-ellipsoid nanoarray, realizing plasmonic color printing with features of low cost, scalable, full color and high flexibility. Our approach provides a feasible way to address the angle-dependent issue in the previous practice of plasmonic color printing, and boosts this field on its way to real-world commercial applications.
Tuning the Water Desalination Performance of Graphenic Layered Nanomaterials by Element Doping and Inter-Layer Spacing*
Authors: Wang Fuxin , Zhang Chao , Yang Yanmei , Qu Yuanyuan , Li Yong-Qiang , Man Baoyuan , Li Weifeng
Published: November 2020

Through atomic molecular dynamics simulations, we investigate the performance of two graphenic materials, boron (BC3) and nitrogen doped graphene (C3N), for seawater desalination and salt rejection, and take pristine graphene as a control. Effects of inter-layer separation have been explored. When water is filtered along the transverse directions of three-layered nanomaterials, the optimal inter-layer separation is 0.7–0.9 nm, which results in high water permeability and salt obstruction capability. The water permeability is considerably higher than porous graphene filter, and is about two orders of magnitude higher than commercial reverse osmosis (RO) membrane. By changing the inter-layer spacing, the water permeability of three graphenic layered nanomaterials follows an order of C3N ≥ GRA > BC3 under the same working conditions. Amongst three nanomaterials, BC3 is more sensitive to inter-layer separation which offers a possibility to control the water desalination speed by mechanically changing the membrane thickness. This is caused by the intrinsic charge transfer inside BC3 that results in periodic distributed water clusters around the layer surface. Our present results reveal the high potentiality of multi-layered graphenic materials for controlled water desalination. It is hopeful that the present work can guide design and fabrication of highly efficient and tunable desalination architectures.
Distinct Three-Level Spin–Orbit Control Associated with Electrically Controlled Band Swapping*
Authors: Suo Yu , Yang Hao , Fu Jiyong
Published: November 2020

We investigate the Rashba and Dressehaus spin–orbit (SO) couplings in an ordinary GaAs/AlGaAs asymmetric double well, which favors the electron occupancy of three subbands ν = 1, 2, 3. Resorting to an external gate, which adjusts the electron occupancy and the well symmetry, we demonstrate distinct three-level SO control of both Rashba (αν
) and Dresselhaus (βν
) intraband terms. Remarkably, as the gate varies, the first-subband SO parameters α
1 and β
1 comply with the usual linear behavior, while α
2 (β
2) and α
3 (β
3) respectively for the second and third subbands interchange the values, triggered by a gate controlled band swapping. This provides a pathway towards fascinating selective SO control in spintronic applications. Moreover, we observe that the interband Rashba (ημν
) and Dresselhaus (Γμν
) terms also exhibit contrasting gate dependence. Our results should stimulate experiments probing SO couplings in multi-subband wells and adopting relevant SO features in future spintronic devices.
State-Dependent Topological Invariants and Anomalous Bulk-Boundary Correspondence in Non-Hermitian Topological Systems with Generalized Inversion Symmetry
Authors: Wang Xiao-Ran , Guo Cui-Xian , Du Qian , Kou Su-Peng
Published: November 2020

Breakdown of bulk-boundary correspondence in non-Hermitian (NH) topological systems with generalized inversion symmetries is a controversial issue. The non-Bloch topological invariants determine the existence of edge states, but fail to describe the number and distribution of defective edge states in non-Hermitian topological systems. The state-dependent topological invariants, instead of a global topological invariant, are developed to accurately characterize the bulk-boundary correspondence of the NH systems, which is very different from their Hermitian counterparts. At the same time, we obtain the accurate phase diagram of the one-dimensional non-Hermitian Su–Schrieffer–Heeger model with a generalized inversion symmetry from the state-dependent topological invariants. Therefore, these results will be helpful for understanding the exotic topological properties of various non-Hermitian systems.
Superconductor-Metal Quantum Transition at the EuO/KTaO3 Interface*
Authors: Ma Yang , Niu Jiasen , Xing Wenyu , Yao Yunyan , Cai Ranran , Sun Jirong , Xie X. C. , Lin Xi , Han Wei
Published: November 2020

We report the experimental investigation of the superconductor-metal quantum phase transition of the EuO/KTaO3 interface. Around the transition, a divergence of the dynamical critical exponent is observed, which supports the quantum Griffiths singularity in the EuO/KTaO3 interface. The quantum Griffiths singularity could be attributed to large rare superconducting regions and quenched disorders at the interface. Our results could pave the way for studying the exotic superconducting properties at the EuO/KTaO3 interface.
Comparison of Proton Shower Developments in the BGO Calorimeter of the Dark Matter Particle Explorer between GEANT4 and FLUKA Simulations*
Authors: Jiang Wei , Yue Chuan , Cui Ming-Yang , Li Xiang , Yuan Qiang , Alemanno Francesca , Bernardini Paolo , Catanzani Giovanni , Chen Zhan-Fang , Mitri Ivan De , Dong Tie-Kuang , Donvito Giacinto , Droz David Francois , Fusco Piergiorgio , Gargano Fabio , Guo Dong-Ya , Kyratzis Dimitrios , Lei Shi-Jun , Liu Yang , Loparco Francesco , Ma Peng-Xiong , Marsella Giovanni , Mazziotta Mario Nicola , Pan Xu , Peng Wen-Xi , Surdo Antonio , Tykhonov Andrii , Wei Yi-Yeng , Yu Yu-Hong , Zang Jing-Jing , Zhang Ya-Peng , Zhang Yong-Jie , Zhang Yun-Long
Published: November 2020

The DArk Matter Particle Explorer (DAMPE) is a satellite-borne detector for high-energy cosmic rays andγ-rays. To fully understand the detector performance and obtain reliable physical results, extensive simulations of the detector are necessary. The simulations are particularly important for the data analysis of cosmic ray nuclei, which relies closely on the hadronic and nuclear interactions of particles in the detector material. Widely adopted simulation softwares include the GEANT4 and FLUKA, both of which have been implemented for the DAMPE simulation tool. Here we describe the simulation tool of DAMPE and compare the results of proton shower properties in the calorimeter from the two simulation softwares. Such a comparison gives an estimate of the most significant uncertainties of our proton spectral analysis.
Reply to the Comment on ‘Improving series convergence: the simple pendulum and beyond’
Authors: Duki Solomon F , Doerr T P , Yu Yi-Kuo
Published: November 2020

We correct an error pointed out by a reader in an example included in a previous article about a method for improving series convergence. After the correction, the conclusion of the previous article, that the method reduces the number of terms needed to achieve a desired accuracy, remains true. We clarify that when the evaluation of an integral requires a series expansion, we measure the speed of convergence by the inverse of the number of terms required to achieve a certain accuracy. In most cases, fewer terms will mean less computational expense. We provide an additional example to emphasize the generality of the method in the previous article.
Tikhonov regularization for polynomial approximation problems in Gauss quadrature points
Authors: An Congpei , Wu Hao-Ning
Published: November 2020

This paper is concerned with the introduction of Tikhonov regularization into least squares approximation scheme on [−1, 1] by orthonormal polynomials, in order to handle noisy data. This scheme includes interpolation and hyperinterpolation as special cases. With Gauss quadrature points employed as nodes, coefficients of the approximation polynomial with respect to given basis are derived in an entry-wise closed form. Under interpolatory conditions, the solution to the regularized approximation problem is rewritten in forms of two kinds of barycentric interpolation formulae, by introducing only a multiplicative correction factor into both classical barycentric formulae. An L
2 error bound and a uniform error bound are derived, providing similar information that Tikhonov regularization is able to reduce the operator norm (Lebesgue constant) and the error term related to the level of noise, both by multiplying a correction factor which is less than one. Numerical examples show the benefits of Tikhonov regularization when data is noisy or data size is relatively small.
Two-dimensional correlation analysis for x-ray photoelectron spectroscopy
Authors: Li S , Driver T , Al Haddad A , Champenois E G , Agåker M , Alexander O , Barillot T , Bostedt C , Garratt D , Kjellsson L , Lutman A A , Rubensson J-E , Sathe C , Marinelli A , Marangos J P , Cryan J P
Published: November 2020

X-ray photoelectron spectroscopy (XPS) measures the binding energy of core-level electrons, which are well-localised to specific atomic sites in a molecular system, providing valuable information on the local chemical environment. The technique relies on measuring the photoelectron spectrum upon x-ray photoionisation, and the resolution is often limited by the bandwidth of the ionising x-ray pulse. This is particularly problematic for time-resolved XPS, where the desired time resolution enforces a fundamental lower limit on the bandwidth of the x-ray source. In this work, we report a novel correlation analysis which exploits the correlation between the x-ray and photoelectron spectra to improve the resolution of XPS measurements. We show that with this correlation-based spectral-domain ghost imaging method we can achieve sub-bandwidth resolution in XPS measurements. This analysis method enables XPS for sources with large bandwidth or spectral jitter, previously considered unfeasible for XPS measurements.
Label-free characterization of ischemic cerebral injury using intravital two-photon excitation fluorescence lifetime imaging microscopy
Authors: Li Hui , Yin Yixuan , Xiang Feng , Yu Jia , Wu Ting , Liu Lina , Liao Jiuling , Zheng Wei
Published: November 2020

Characterizing an ischemic brain injury at its early stage is critical to biological research and the clinical diagnosis of cerebral ischemia-related diseases. However, approaches with intravital, label-free, and real-time characterization capabilities are scarce. Two-photon excitation fluorescence lifetime imaging microscopy (FLIM) can detect variations in energy metabolism based on the autofluorescence of reduced nicotinamide adenine dinucleotide (NADH). Using this unique feature, we proposed a novel approach for cerebral ischemia characterization. From investigating cell and animal models, the cerebral NADH fluorescence lifetime was observed to be sensitive to metabolic changes caused by ischemia and consistent with ischemic time. A comparison with standard blood flow imaging and neuronal injury assessment further suggests that, the two-photon FLIM, using NADH as an indicator, can characterize degrees of cerebral ischemia and related injuries, particularly at the early stage. These findings demonstrate that NADH FLIM is promising for providing intravital, label-free, and real-time assessment of cerebral ischemia and ischemic brain injury that will be significant to the study and diagnosis of related diseases.
Atmospheric dielectric barrier discharge containing helium–air mixtures: the effect of dry air impurities on the spatial discharge behavior
Authors: Wang Qiao , Dai Dong , Ning Wenjun , Zhang Yuhui
Published: November 2020

Air is a typical and arguably unavoidable impurity in atmospheric pressure dielectric barrier discharges (DBDs). The introduction of air may bring rich plasma chemical effects on DBDs and lead to a significant change of discharge characteristics. Here we implement a two-dimensional fluid model to study the spatial discharge behavior in a helium–dry-air DBD under the air impurity level (N
air) of 10–200 ppm. The simulation results reveal that under low impurity content (less than 30 ppm), the gas gap cannot be ignited due to the feeble Penning ionization during the breakdown. However, with an elevation in the impurity level, the progressively enhanced Penning ionization makes the DBD experience three different spatial modes, namely uniform, columnar, and complementary quasi-uniform modes. Of particular note is that the improvement of discharge uniformity observed after the second mode transition is not directly controlled by seed electron level—a previously reported qualitative indicator of the discharge uniformity concluded by helium DBDs with only nitrogen traces. And the main contributor to this phenomenon is the complementary spatial structure appearing in successive two discharges induced by the further reinforced Penning ionization with extra oxygen doped. The result suggests the necessity of considering oxygen in helium–air DBDs when the impurity effect of air is concerned.
Influence of triaxial deformation on wobbling motion in even–even nuclei
Authors: Qi B , Zhang H , Wang S Y , Chen Q B
Published: November 2020

The influence of triaxial deformation γ on the purely collective form of wobbling motion in even–even nuclei is discussed based on the triaxial rotor model. It is found that the harmonic approximation is realized well when the value γ = 30° is adopted for the properties of energy spectra and electric quadrupole transition probabilities, while this approximation gets worse when γ gradually deviates from 30°. Recent data from a Coulomb excitation experiment, namely

3

1

+

and

2

2

+

for 110Ru, are studied and might be suggested as the bandhead of the wobbling bands. In addition, two types of angular momentum geometries for wobbling motion, stemming from different γ values, are exhibited by the azimuthal plots.
The effect of iron doping on the structural, optical, surface morphological, and temperature-dependent magnetic properties of ZnO nanoparticles
Authors: Anbuselvan D , Nilavazhagan S , Santhanam A , Chidhambaram N , Kanimozhi G , Ahamad Tansir , Alshehri Saad M
Published: November 2020

This study reports the role of temperature on the magnetic properties of the Fe-doped (0, 1, 3, and 5 wt%) ZnO nanoparticles (NPs) synthesized using the facile co-precipitation procedure. Powder x-ray diffraction analysis revealed the crystallinity deterioration of the ZnO matrix on trivalent cationic doping and the shifting of peak position due to the mismatch in ionic radius between the Zn2+ and Fe3+. A clear redshift in the bandgap of the iron-doped ZnO samples is observed from the UV–vis diffused reflectance spectroscopic studies. The existence of lattice defects including the zinc interstitials, zinc vacancies, and oxygen vacancies are confirmed by the room temperature photoluminescence analysis. Scanning electron microscopic investigations showed the synthesized NPs possesses agglomerated spherical morphology. The role of temperature on the magnetization of the iron-doped ZnO nanoparticles has been examined at 300 and 100 K. A 3-fold enhancement of magnetization value perceived for the 5% iron-doped ZnO nanoparticles at 100 K compared to the magnetization value of such sample at 300 K.
The spin-polarized edge states of blue phosphorene nanoribbons induced by electric field and electron doping
Authors: Zhang Shidong , Li Yun , Wang Yun-Peng , Li Jialin , Li Mingjun , Long Mengqiu
Published: November 2020

Edge states of various two-dimensional materials such as graphene are intrinsically spin-polarized. In other materials, electric field and charge doping are required for introducing magnetism to their edges. In this work, by using first-principles calculations, we studied the effects of transverse electric field on the edge states of the armchair blue phosphorene nanoribbon (ABPNR), and found that a transverse electric field drives the edge electronic state occupied and at the same time spin-polarized. We also doped electrons to the ABPNR and found that these additional electrons occupy and spin-polarize the electronic states of both edges of the nanoribbon.
Powder diffraction computed tomography: a combined synchrotron and neutron study
Authors: Kochetov Vladislav , Mühlbauer Martin J , Schökel Alexander , Fischer Torben , Müller Timo , Hofmann Michael , Staron Peter , Lienert Ulrich , Petry Winfried , Senyshyn Anatoliy
Published: November 2020

Diffraction and imaging using x-rays and neutrons are widely utilized in different fields of engineering, biology, chemistry and/or materials science. The additional information gained from the diffraction signal by x-ray diffraction and computed tomography (XRD-CT) can give this method a distinct advantage in materials science applications compared to classical tomography. Its active development over the last decade revealed structural details in a non-destructive way with unprecedented sensitivity. In the current contribution an attempt to adopt the well-established XRD-CT technique for neutron diffraction computed tomography (ND-CT) is reported. A specially designed ‘phantom’, an object displaying adaptable contrast sufficient for both XRD-CT and ND-CT, was used for method validation. The feasibility of ND-CT is demonstrated, and it is also shown that the ND-CT technique is capable to provide a non-destructive view into the interior of the ‘phantom’ delivering structural information consistent with a reference XRD-CT experiment.
Studies on magnetocaloric effect of Tb2Ni0.90Si2.94 compound
Authors: Pakhira Santanu , Kundu Mily , Ranganathan R , Mazumdar Chandan
Published: November 2020

A comparative study has been carried out on the magnetocaloric properties of as-cast and annealed Tb2Ni0.90Si2.94 intermetallic compound. While the as-cast material exhibits ferromagnetic cluster-glass behaviour below 9.9 K coexisting with antiferromagnetic (AFM) interaction, the annealed system shows AFM ordering below 13.5 K and spin freezing occurs below 4 K. The compound exhibits moderate magnetocaloric performance with maximum isothermal entropy changes (−ΔS
M) 8.8 and 10.9 J kg−1 K−1, relative cooling power (RCP) 306 and 365 J kg−1, along with adiabatic temperature change (ΔT
ad) 5.5 and 8.15 K for 70 kOe magnetic field change in as-cast and annealed forms, respectively. The estimated magnetic entropy change is found to be larger for annealed sample in comparison to that of as-cast analogue. However, the full width at half maxima (FWHM) of −ΔS
M(T) behaviour is larger in as-cast compound due to the presence of inherent structural disorder which reduces with thermal annealing. A positive isothermal entropy change (−ΔS
M) and adiabatic temperature change (ΔT
ad) is observed for the as-cast compound in the measured field and temperature region. In contrast, the annealed system exhibits inverse magnetocaloric effect in the low field and temperature region where AFM interactions dominate. Magnetocaloric effect (MCE) is used as a tool to establish a subtle correlation between the observed magnetocaloric effect and the reported magnetic properties of the system.
Adaptive quaternion particle filter using generalized likelihood ratio test for aircraft attitude estimation in the presence of anomalous measurement
Authors: Zhou Zhaihe , Zhang Qianyun , Liu Qiqi , Zeng Qingxi , Tian Xiangrui
Published: November 2020

An adaptive quaternion particle filter (QPF) based on the generalized likelihood ratio test (GLRT) is proposed for aircraft attitude estimation in the presence of an anomalous measurement. The framework of the QPF is employed to guarantee quaternion normalization. To cope with an anomalous measurement when interference occurs, the proposed algorithm uses the GLRT to detect an anomalous measurement and determine the interference source. An adaptation scheme is used to tune the measurement noise covariance matrix after the interference source has been determined so that the algorithm can remain robust against interference. Numerical simulations are carried out to evaluate the performance of the proposed algorithm and compare it with the QPF algorithm. The results show that the proposed algorithm outperforms the standard one in attitude estimation accuracy under anomalous measurement conditions.
LeXtender: a software package for advanced MOKE acquisition and analysis
Authors: Gräfe Joachim , Groß Felix , Ilse Sven E , Boltje Daan B , Muralidhar Shreyas , Goering Eberhard J
Published: November 2020

Contemporary scanning laser Kerr magnetometers are very efficient measurement devices that achieve very good signal to noise ratios and spatial resolution for magnetization measurements. When going beyond simple hysteresis loop measurements, large amounts of data can be acquired quickly and, thus, control software and automated processing becomes necessary to go beyond these simple measurements. Here, we present an open source software that realizes first-order reversal curves and magnetic property mapping based on scanning laser Kerr magnetometry. The modular software is easily extensible and provides a convenient user interface to make these more complex measurements accessible to a broader user base.
Weighted kurtosis-based VMD and improved frequency-weighted energy operator low-speed bearing-fault diagnosis
Authors: Song Xuewei , Wang Hongfeng , Chen Peng
Published: November 2020

The diagnosis of low-speed bearing faults remains a challenging issue because background noise is often present and the impulse signal is prone to being masked. In this paper, we propose a low-speed bearing-fault diagnosis method using weighted-kurtosis variational-mode decomposition and an improved frequency-weighted energy operator (IFWEO). First, the raw signal is decomposed using VMD, and WK is employed to select the optimum intrinsic mode function to reconstruct the signal. The reconstructed signal carries abundant fault information. Second, a third-order cumulant method is introduced to improve the FWEO, and this method is able to strengthen the signal impulse and enhance the fault features. The IFWEO is able to effectively reduce the effects of noise. Third, the effectiveness of the proposed method is validated by simulation and engineering experiments, and the results show that the method presented here is able to accurately diagnose low-speed bearing faults.
PIV measurements using refraction at a solid–fluid interface
Authors: Cabut Damien , Michard Marc , Simoëns Serge , Todoroff Violaine , Hermange Corentin , Le-Chenadec Yohan
Published: November 2020

Laser light sheet refraction at the fluid flow–window interface is proposed to perform fluorescent particle image velocimetry (PIV) measurements, in particular for cases in which optical access limits the possibilities of illuminating a flow with a planar collimated light sheet. The study of laser sheet propagation in the present measurement method is led by ray tracing to quantify the illumination intensity. To describe the limitations of this developed PIV version (refracted PIV (R-PIV)), we proposed a cross-correlation model (CCM) for analyzing image pairs that is an extension of the models used in the cases of µ-PIV or planar PIV (P-PIV) techniques. This CCM accounts for the R-PIV optical constraints of (1) in-depth and longitudinal inhomogeneities of the light sheet refraction at the location of the object plane or (2) integration in depth of the fluorescence from seeding particles. This R-PIV and the P-PIV techniques are further compared in the case of an academic pipe flow for which the analytic solution is known. Our extended CCM function is finally applied, given the theoretical flow velocity, the flow illumination and the seeding flow parameters, to analyze error levels in determining the real flow velocity field.
Hypoxia-responsive nanogel as IL-12 carrier for anti-cancer therapy
Authors: Zhang Changhuan , Li Qinghua , Wu Chenghu , Wang Jilong , Su Ming , Deng Junjie
Published: November 2020

In the past two decades, protein drugs have evolved to become the most successful and important strategy in cancer therapy. However, systematical administration of protein drugs may cause serious side effects. In order to prepare a new promising hydrophilic drugs carrier, we constructed a PEGylated hyaluronic acid nanogel (NI-MAHA-PEG nanogel) with hypoxia and enzymatic responsiveness, which can selectively release hydrophilic drugs interleukin-12 (IL-12) on demand in a tumor microenvironment. We observed that release of IL-12 from nanogels by hypoxia-responsive stimulation, nanogels have anti-tumor effects on melanoma. Compared with physiological conditions, the IL-12 release rate has achieved remarkable growth under hypoxic conditions. Similarly, the drug release rate increased significantly with the addition of 500 U ml−1 hyaluronidase. We provide a novel strategy to allow efficient delivery, on-demand release, and enhanced access of proteins to hypoxic tumor regions. The rational design of this nanogels drug delivery system can further explore the use of various drugs to treat many cancers.
Selective synthesis of DC carbon arc-generated carbon nanotube and layered-graphene and the associated mechanism
Authors: Karmakar Soumen
Published: November 2020

Herein we report how an anode is eroded and the eroded mass is deposited on the cathode surface at different arc currents (

I

a
r
c

) in a DC carbon arc discharge using roughly oriented graphite (ROG) as electrodes. It was found that the nature of anode erosion critically depends on

I

a
r
c

,

and has profound effects on the morphology of the as-synthesized cathode deposits (CDs), the conversion efficiency of the system to form the CDs and their compositions. By characterizing the as-synthesized CDs in their totality by transmission electron microscopy, Raman spectroscopy, and x-ray diffraction it was found that there exists a critical value of

I

a
r
c

,

below which the arc remains constricted, and above which the arc becomes intense. It was further found that the system can selectively generate both carbon nanotubes (CNTs) and layered-graphene sheets (LGs) when the carbon arc runs in constricted and intense modes, respectively. By the suitable adjustment of

I

a
r
c

,

it is possible to switchover between the aforementioned arc-modes. Based on the experimental results, a semi-empirical model encompassing the plausible effects of rapid and random movement of the anode spot on the used ROG anode surface was developed to provide new insights into the growth mechanism of arc-generated CNTs and LGs. The state-of-the-art presented in this paper could facilitate the carbon arc discharge route for the tailored synthesis of highly crystalline CNTs and LGs.
Coefficient of restitution for an obliquely bouncing ball
Authors: Cross Rod
Published: November 2020

A simple experiment for students is to measure the coefficient of restitution (COR) for a vertical bounce on a horizontal surface. In this paper, measurements are presented of the COR for a tennis ball bouncing at an oblique angle on a horizontal surface. Changes in the horizontal and rotation speeds were also measured, by filming the bounce with a video camera. A measurement of this type involves a more extensive examination of basic mechanics, since the friction force acting at the bottom of the ball acts to change both the horizontal speed of the ball and its rotational velocity. The COR for an oblique bounce was found to be larger than that for a vertical bounce and was also found to depend on the incident spin of the ball.
Enhancing digital tomosynthesis (DTS) for lung radiotherapy guidance using patient-specific deep learning model
Authors: Jiang Zhuoran , Yin Fang-Fang , Ge Yun , Ren Lei
Published: November 2020

Digital tomosynthesis (DTS) has been proposed as a fast low-dose imaging technique for image-guided radiation therapy (IGRT). However, due to the limited scanning angle, DTS reconstructed by the conventional FDK method suffers from significant distortions and poor plane-to-plane resolutions without full volumetric information, which severely limits its capability for image guidance. Although existing deep learning-based methods showed feasibilities in restoring volumetric information in DTS, they ignored the inter-patient variabilities by training the model using group patients. Consequently, the restored images still suffered from blurred and inaccurate edges. In this study, we presented a DTS enhancement method based on a patient-specific deep learning model to recover the volumetric information in DTS images. The main idea is to use the patient-specific prior knowledge to train the model to learn the patient-specific correlation between DTS and the ground truth volumetric images. To validate the performance of the proposed method, we enrolled both simulated and real on-board projections from lung cancer patient data. Results demonstrated the benefits of the proposed method: (1) qualitatively, DTS enhanced by the proposed method shows CT-like high image quality with accurate and clear edges; (2) quantitatively, the enhanced DTS has low-intensity errors and high structural similarity with respect to the ground truth CT images; (3) in the tumor localization study, compared to the ground truth CT-CBCT registration, the enhanced DTS shows 3D localization errors of ≤0.7 mm and ≤1.6 mm for studies using simulated and real projections, respectively; and (4), the DTS enhancement is nearly real-time. Overall, the proposed method is effective and efficient in enhancing DTS to make it a valuable tool for IGRT applications.
Patient’s body composition can significantly affect RF power deposition in the tissue around DBS implants: ramifications for lead management strategies and MRI field-shaping techniques
Authors: Bhusal Bhumi , Keil Boris , Rosenow Joshua , Kazemivalipour Ehsan , Golestanirad Laleh
Published: November 2020

Patients with active implants such as deep brain stimulation (DBS) devices have limited access to magnetic resonance imaging (MRI) due to risks associated with RF heating of implants in MRI environment. With an aging population and increased prevalence of neurodegenerative disease, the indication for MRI exams in patients with such implants increases as well. In response to this growing need, many groups have investigated strategies to mitigate RF heating of DBS implants during MRI. These efforts fall into two main categories: MRI field-shaping methods, where the electric field of the MRI RF coil is modified to reduce the interaction with implanted leads, and lead management techniques where surgical modifications in the trajectory reduces the coupling with RF fields. Studies that characterize these techniques, however, have relied either on simulations with homogenous body models, or experiments with box-shaped single-material phantoms. It is well established, however, that the shape and heterogeneity of human body affects the distribution of RF electric fields, which by proxy, alters the heating of an implant inside the body. In this contribution, we applied numerical simulations and phantom experiments to examine the degree to which variations in patient’s body composition affects RF power deposition. We then assessed effectiveness of RF-heating mitigation strategies under variant patient body compositions. Our results demonstrated that patient’s body composition substantially alters RF power deposition in the tissue around implanted leads. However, both techniques based on MRI field-shaping and DBS lead management performed well under variant body types.
Actual delivered dose calculation on intra-irradiation cone-beam computed tomography images: a phantom study
Authors: Iramina Hiraku , Nakamura Mitsuhiro , Mizowaki Takashi
Published: November 2020

Cone-beam computed tomography (CBCT) images acquired during volumetric modulated arc therapy (VMAT; ii-CBCT) can be used to calculate actual delivered doses (ADDs). However, such ii-CBCT images are degraded by scattered megavoltage x-rays (MV-scatters). We aimed to evaluate the dose calculation accuracy of the MV-scatter uncorrected or corrected ii-CBCT images acquired during VMAT deliveries. For MV-scatter correction on concurrent kilovoltage projections (P
MVkV), projections consisting only of MV-scatters (P
MVS) were acquired under the same MV beam parameters and gantry angles and subtracted from P
MVkV (P
MVScorr). In addition, the projections by kilovoltage beams were acquired for reference (P
kV). The corresponding CBCT images were reconstructed using the Feldkamp–Davis–Kress algorithm (CBCTMVkV, CBCTMVScorr, and CBCTkV as reference). A multi-energy phantom with rods of various relative electron densities (REDs) was used to generate a CBCT-number-to-RED conversion table. First, CBCTkV was reconstructed. Then, the mean CBCT-numbers within each rod were extracted, and a reference table was generated. Concurrent kilovoltage imaging with various field sizes was also demonstrated, and CBCTMVkV and CBCTMVScorr were reconstructed. The extracted CBCT-numbers of each ii-CBCT image were converted into REDs using the reference table. Next, the absolute differences of RED between the ii-CBCT image and CBCTkV were calculated. Ten VMAT plans using a 10 MV flattening-filter-free beam were used for concurrent imaging of an anthropomorphic torso phantom. Moreover, an iterative reconstruction algorithm (IRA) was used for CBCTMVScorr. The plans were recalculated for the corresponding CBCTMVkV, CBCTMVScorr, CBCTMVScorr+IRA, and CBCTkV with the reference table. Finally, the doses were evaluated using 3D gamma analysis (1%/1 mm). The median difference ranges between CBCTMVkV/CBCTMVScorr and the reference values were −0.58 to −0.10/−0.03 to 0.00. The median gamma pass rates of the doses on CBCTMVkV, CBCTMVScorr, and CBCTMVScorr+IRA to the rate on CBCTkV were 70.4, 99.5, and 98.2%, respectively. CBCTMVScorr were comparable with CBCTkV for calculating the ADD from VMAT.
Age- and gender-associated differences in the sleepy brain’s electroencephalogram
Authors: Putilov Arcady A , Donskaya Olga G , Poluektov Mikhail G , Dorokhov Vladimir B
Published: November 2020

Background. With the eyes closed, an increase in sleepiness is associated with a decrease of spectral electroencephalographic (EEG) power in the high-frequency rage (i.e. alpha activity) and an increase of the power in the low-frequency range (i.e. theta activity). It has been suggested that the changes in the high- and low-frequency ranges might determine the two (earlier and later) drowsiness stages that precede sleep onset, respectively. Objective. We tested whether such spectral EEG signatures of sleepiness vary with age or gender. Approach. The EEG signal was recorded at 2 h intervals in 48 volunteers (15–67 years, 27 females) deprived of sleep between Friday evening and Sunday evening. The EEG signatures of sleepiness were calculated by expressing each EEG spectrum as a deviation from the initial (Friday evening) EEG spectrum. Main results. An age- and gender-specific variation was found in the signatures. Only the pattern of age-associated variation changed with an increase in the sleepiness level. A two-stage response to the increase of sleepiness was confirmed, but only in younger study participants. Subjective sleepiness was associated with neither age nor gender. Significance. In sleep-deprivation research, accounting for age- and gender-specific variations in the spectral EEG measures of drowsiness might be recommended. The results did not reveal any disturbance of the motivational function of subjective sleepiness in older study participants.
Understanding asymmetries using integrated simulations of capsule implosions in low gas-fill hohlraums at the National Ignition Facility
Authors: Milovich J L , Casey D C , MacGowan B , Clark D , Mariscal D , Ma T , Baker K , Bionta R , Hahn K , Moore A , Schlossberg D , Hartouni E , Sepke S , Landen O
Published: November 2020

Current capsule implosions at the National Ignition Facility (NIF) using high-density-carbon ablators and laser energies close to 2 MJ have shown neutron yields in excess of 50 kJ. Improving on this performance requires understanding of the different degradation mechanisms. For many NIF implosions, nuclear diagnostic signatures have inferred residual hot-spot velocities that correlate with fuel areal density variations consistent with a low-order mode-1 asymmetry. A current working hypothesis attributes these asymmetries to a combination of beam to beam variations in the laser delivery and possibly coupling to target features, such as the diagnostic holes needed for x-ray imaging. Recently, a new source has been identified, thickness variation in the ablator shell. To gain better understanding and eventually mitigate the causes of

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asymmetries, 3D integrated simulations using the actual delivered laser powers are needed. To capture the effect of the diagnostic holes (DHs) using direct numerical simulation would require significantly large computational resources. Instead, our 3D simulations make use of a subgrid model developed using highly-resolved 2D simulations that include several details of the DH engineering complexity. Simulations of NIF shots using hohlraums without DHs, to isolate the effect of beam-to-beam variations, reproduce fairly well the observed nuclear diagnostic signatures. Similarly, reasonable agreement between data and simulations is also obtained in the presence of diagnostic holes. To account for the remaining discrepancies a sensitivity study of ablator thickness variation showed that 1% thickness asymmetries are comparable in effect to 1% peak drive mode-1 asymmetries. Additionally, this study identified sensitivity to variations in the imbedded doped layer (needed to shield the DT ice from the high energy x-rays generated in the hohlraum) thickness even when the inner and outer surface of the ablator are perfectly spherical.
Fast species ranking for iterative species-oriented skeletal reduction of chemistry sets
Authors: Hanicinec Martin , Mohr Sebastian , Tennyson Jonathan
Published: November 2020

A fast algorithm is developed for ranking the species in a chemistry set according to their importance to the modeled densities of user-specified species of interest. The species ranking can be constructed for any set of user-specified plasma conditions, but here we focus predominantly on low-temperature plasmas, with gas temperatures between 300 and 1500 K covering the typical range of ICP and CCP plasma sources. This ranking scheme can be used to acquire insight into complex chemistry sets for modeling plasma phenomena or for a species-oriented reduction of the given chemistry set. The species-ranking method presented is based on a graph-theoretical representation of the detailed chemistry set and establishing indirect asymmetric coupling coefficients between pairs of species by the means of widely used graph search algorithms. Several alternative species-ranking schemes are proposed, all building on the theory behind different flavors of the directed relation graph method. The best-performing ranking method is identified statistically, by performing and evaluating a species-oriented iterative skeletal reduction on six, previously available, test chemistry sets (including O2–He and N2–H2) with varying plasma conditions. The species-ranking method presented leads to reductions of between 10 and 75% in the number of species compared to the original detailed chemistry set, depending on the specific test chemistry set and plasma conditions.
Design of a triple pocket multi-gate material TFET structure for low-power applications
Authors: Ahmad Syed Afzal , Alam Naushad
Published: November 2020

In this paper we propose a triple-pocket multi-gate material TFET (TP-TFET) device structure for a low-power and high-performance circuit design. The proposed device structure integrates the good features of both the conventional MOSFET and tunnel FET. This is achieved through three doped pockets and dual work-function gate material on near the source–channel junction. In the proposed device, the ON state conduction mechanism is dominated by an over-the-barrier thermal diffusion of carriers, thereby offering a high-value drive current. On the other hand, the subthreshold conduction mechanism is dominated by the tunnelling of carriers, thereby incurring a very small leakage current and offering a small subthreshold slope. We use 2D TCAD device simulations for the analysis of the TP-TFET and its comparison with the existing pocketed-heterogate TFET (PHG-TFET). We observe that the proposed TFET offers the average subthreshold slope (SSavg) of 2.85 mV dec−1 and ON current of ∼230 µA µm−1 as compared to the existing PHG-TFET, which offers SSavg of 44.91 mV dec−1 and I
ON = ∼62 µA µm−1. Further, some benchmark circuits are implemented using these devices. A ring oscillator designed using the TP-TFET shows approximately a 6× higher frequency as compared to that designed using the PHG-TFET. The power delay product of the NAND gate and NOR gate obtained using these devices differ by approximately 3× to 20× as the supply voltage is decreased from 1.0 to 0.5 V.
Time-reversal symmetry violations and entropy production in field theories of polar active matter
Authors: Borthne Øyvind L , Fodor Étienne , Cates Michael E
Published: November 2020

We investigate the steady-state entropy production rate (EPR) in the hydrodynamic Vicsek model (HVM) and diffusive flocking model (DFM). Both models display a transition from an isotropic gas to a polar liquid (flocking) phase, in addition to travelling polar clusters and microphase-separation in the miscibility gap. The phase diagram of the DFM, which may be considered an extension of the HVM, contains additional structure at low densities where we find a novel crystal phase in which a stationary hexagonal lattice of high-density ridges surround low density valleys. From an assessment of the scaling of the EPR at low noise, we uncover that the dynamics in this limit may be organised into three main classes based on the dominant contribution. Truly nonequilibrium dynamics is characterised by a divergent EPR in this limit, and sustains global time-reversal symmetry (TRS) violating currents at zero noise. On the other hand, marginally nonequilibrium and effectively equilibrium dynamics have a finite EPR in this limit, and TRS is broken only at the level of fluctuations. For the latter of these two cases, detailed balance is restored in the small noise limit and we recover effective Boltzmann statistics to lowest nontrivial order. We further demonstrate that the scaling of the EPR may change depending on the dynamical variables that are tracked when it is computed, and the protocol chosen for time-reversal. Results acquired from numerical simulations of the dynamics confirm both the asymptotic scaling relations we derive and our quantitative predictions.