bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modulation instability of two TE modes in a thin left-handed film on a nonlinear right-handed substrate
Authors: Buller A.S. , Zelenetskaya Yu.V. , Litvinov R.V. , Melikhova N.R. 
Published: November 2021

AbstractThe intramode wave beams in a thin left-handed film on a Kerr substrate are considered at a frequency near zero mode group velocity. Four coupled (1 + 1)-dimensional nonlinear Schrödinger equations, describing the interaction of forward and backward propagating beams with positive and negative group velocities, are derived. It is shown that self- and cross-phase modulation for four simultaneously propagating modes is possible only at strictly matched perturbations of their propagation constants, which is due to the contribution of spatial parametric mixing. The modulation instability of only two waveguide modes is analysed for different versions of their propagation. The specific features of modulation instability, related to the propagation of modes with negative group velocities, are investigated.
Efficiency improvement of the femtosecond laser source of superponderomotive electrons and X-ray radiation due to the use of near-critical density targets
Authors: Andreev N.E. , Popov V.S. , Rosmej O.N. , Kuzmin A.A. , Shaykin A.A. , Khazanov E.A. , Kotov A.V. , Borisenko N.G. , Starodubtsev M.V. , Soloviev A.A. 
Published: November 2021

Abstract
We consider the possibility of improving the superhigh-power laser pulse to superponderomotive electrons energy conversion efficiency by using porous targets of near-critical density. We report the results of numerical simulations based on the typical parameters of laser pulses of the PEARL laser facility built on the principles of parametric chirped pulse amplification (OPCPA). An original scheme for producing a controllable prepulse based on the use of a pump laser switched to a two-pulse regime is discussed. The prepulse is required to homogenise the submicron inhomogeneities of a porous target. Simulations show a significant increase in the laser-to-electron energy conversion efficiency in comparison with solid-state and gas targets. This interaction regime can be used to improve the efficiency of a broad class of laser-driven secondary radiation sources, such as a betatron source, bremsstrahlung, neutron source, etc.
Experimental observation of the origin and structure of elastoinertial turbulence
Authors: Choueiri George H. , Lopez Jose M. , Varshney Atul , Sankar Sarath , Hof Björn 
Published: November 2021

Significance
The motion of viscoelastic fluids often strikingly differs from the Newtonian standard case. Elastic fluid properties tend to give rise to instability and chaotic motion at low inertia yet suppress turbulence at high inertia. In experiments of polymer solutions, we identify the dynamical mode that dominates the onset of the recently discovered state of “elastoinertial turbulence” (EIT), and our observations allow us to discriminate between the various theoretical models attempting to explain the state’s origin. Moreover, we demonstrate that the characteristic EIT structures can be traced across more than three orders of magnitude in Reynolds number, suggesting that EIT plays as dominant a role in high-shear viscoelastic flows as ordinary turbulence does in high-inertia Newtonian flows.
Study of coefficient of discharge through orifices
Authors: Wadhwa Ajay 
Published: November 2021

Abstract
A physical quantity called coefficient of discharge, defined as the ratio of actual discharge to the theoretical discharge, is of keen interest in the liquid flow through an orifice. We have investigated the discharge coefficient of the liquid (water) flow through orifices of two different shapes namely the circular and the square. We use the basic arrangement in which the water contained in a long vertical pipe, after falling through a height, is allowed to flow out of an orifice located at its bottom. For our experiment, we have used an Arduino based technique to dynamically record the position of the falling water level as a function of time. We compare the values of the coefficient of discharge obtained in this work with those reported earlier using conventional methods.
Thermal and plasma enhanced atomic layer deposition of ultrathin TiO2 on silicon from amide and alkoxide precursors: growth chemistry and photoelectrochemical performance
Authors: O’Donnell S , Jose F , Shiel K , Snelgrove M , McFeely C , McGill E , O’Connor R 
Published: November 2021

Abstract
Due to its low cost and suitable band gap, silicon has been studied as a photoanode material for some time. However, as a result of poor stability during the oxygen evolution reaction (OER), Si still remains unsuitable for any extended use. Ultra-thin titanium dioxide (TiO2) films have been used as protective coatings and are shown to enhance Si photoanode lifetime with added solar to hydrogen performance improvements through distancing the oxidation reaction away from the Si photoanode surface and improved charge transport through the anode. This study details the nucleation, growth chemistry, and performance of TiO2 thin films prepared via thermal and plasma enhanced atomic layer deposition (ALD) using both titanium isopropoxide and tetrakis(dimethylamido)titanium as the precursor material. The effect of post ALD treatments of plasma and air annealing was also studied. Films were investigated using photoelectrochemical cell testing to evaluate photoelectrochemical performance, and in-vacuum cycle-by-cycle x-ray photoelectron spectroscopy was used as the primary characterisation technique to study nucleation mechanisms and film properties contributing to improvements in cell performance. TiO2 grown by plasma enhanced ALD results in cleaner films with reduced carbon incorporation. However, despite increased carbon incorporation, thermally grown films showed improved photocurrent as a result of oxygen vacancies in these films. Post deposition annealing in a H2 ambient is shown to further improve photocurrent in all cases, while annealing in atmosphere leads to uniform film chemistry and enhanced photocurrent stability in all cases.
Reactive force field-based molecular dynamics simulation of the interaction between plasma reactive oxygen species and the receptor-binding domain of the spike protein in the capsid protein of SARS-CoV-2
Authors: Wang Huichao , Zhao Tong , Yang Shuhui , Zou Liang , Wang Xiaolong , Zhang Yuantao 
Published: November 2021

Abstract
Under the pressures of the current global pandemic, researchers have been working hard to find a reliable way to suppress infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and prevent the spread of COVID-19. Studies have shown that the recognition and binding of human angiotensin-converting enzyme 2 by the receptor-binding domain (RBD) of the spike protein on the surface of SARS-CoV-2 is a crucial step in viral invasion of human receptor cells, and blocking this process could inhibit the virus from invading normal human cells. Plasma treatment can disrupt the structure of the RBD and effectively block the binding process. However, the mechanism by which plasma blocks recognition and binding is not clear. In this study, the reaction between reactive oxygen species (ROS) in plasma and a molecular model of the RBD was simulated using a reactive molecular dynamics method. The results showed that the destruction of the RBD by ROS was triggered by hydrogen abstraction reactions: O and OH abstracted H atoms from the RBD, while the H atoms of H2O2 and HO2 were abstracted by the RBD. This hydrogen abstraction resulted in the breakage of C–H, N–H, O–H and C=O bonds and the formation of C=C and C=N bonds. The addition reaction of OH increased the number of O–H bonds and caused the formation of C–O, N–O and O–H bonds. The dissociation of N–H bonds led to the destruction of the original peptide bond structure and amino acid residues, changed the type of amino acid residues and caused the conversion of N–C and N=C and C=O and C–O. The simulation partially elucidated the microscopic mechanism of the interaction between ROS in plasma and the capsid protein of SARS-CoV-2, providing theoretical support for the control of SARS-CoV-2 infection by plasma, a contribution to overcoming the global pandemic.
Multiplicative modified Rodrigues-parameters-based strong tracking unscented Kalman filter for satellite attitude estimation
Authors: Ma Haining , Lu Zhengliang , Zhang Xiang , Liao Wenhe 
Published: November 2021

Abstract
In this paper, an improved strong tracking unscented Kalman filter based on multiplicative modified Rodrigues parameters (MRPs) is proposed for satellite attitude estimation. The multiplicative MRPs are superior to additive MRPs in terms of attitude representation, especially when attitude angles are large. By minimizing the loss function in Wahba’s problem, a novel method of weighted average for MRPs is derived to replace the simple procedure. The generation of Sigma points, update of state variables, and calculation of covariance matrices are all different from the existing literature to maintain the multiplicative property of MRPs. Simulation results by raw telemetry data from the on-orbit CubeSat Enlai-1 demonstrate the excellent performance of the proposed filter under large attitude angles.
Scale adaptive subdomain matching network for bearing fault diagnosis
Authors: Zhang Di , Wei Yuan , Wang Baoqiang , Liu Shulin 
Published: November 2021

AbstractThe wide application of transfer learning technology can effectively solve the problem of the difference between data collection and actual application equipment of traditional intelligent fault diagnosis methods in the practical application process. However, the difference in subdomain space and the serious imbalance of data samples in the process of simultaneous transfer restricts the deep transfer learning technology to the engineering application of high-precision diagnosis. In order to solve the problem of subdomain matching with different subspaces and unbalanced data samples, in this paper we study the subdomain adaptive method and propose a scale adaptive subdomain matching (SASM) method. The SASM method divides the global feature space according to the sample labels, and features with the same label will be divided into the same sub-feature space. Using the edge distribution of the sample and the category weight of the label, the SASM method can effectively optimize the feature distribution of the same subdomain and the weight distribution of different subdomains. Based on the establishment of a clearer internal structure of features, the field adaptation effect is improved, and the matching ability is enhanced when the sample is unevenly distributed. At the same time, the SASM network (SASMN) method for unsupervised bearing fault diagnosis is constructed and validated by experiments. The results indicate that SASMN can effectively optimize the subdomain adaptive effect, and the diagnostic accuracy of the target domain data set is significantly higher than the other three currently popular domain adaptive fault diagnosis methods.
Editorial for focus on nanophase materials for next-generation lithium-ion batteries and beyond
Authors: Meng Xiangbo , Chen Zonghai , Li Jianlin , Harrison Katharine L , Lu Wenquan , Sun Xueliang 
Published: November 2021

Abstract
Lithium-ion batteries (LIBs) have revolutionized our society in many respects, and we are expecting even more favorable changes in our lifestyles with newer battery technologies. In pursuing such eligible batteries, nanophase materials play some important roles in LIBs and beyond technologies. Stimulated by their beneficial effects of nanophase materials, we initiated this Focus. Excitingly, this Focus collects 13 excellent original research and review articles related to the applications of nanophase materials in various rechargeable batteries, ranging from nanostructured electrode materials, nanoscale interface tailoring, novel separators, computational calculations, and advanced characterizations.
Ideal magnetohydrodynamic stability in stellarators with subsonic equilibrium flow
Authors: Nührenberg C 
Published: November 2021

AbstractThe effect of a subsonic flow, inherent to most stellarators because of a radial electric field, on their ideal magnetohydrodynamic (MHD) stability properties is studied employing the quasi-Lagrangian picture developed by Frieman and Rotenberg (1960Rev. Mod. Phys.32898). The Mach number of the perpendicularE × Bflow in stellarators is of order 0.01 and, therefore, admits the usage of a subsonic approximation in form of a static equilibrium. A mathematical formulation of the weak form of the stability equation with flow has been implemented in the ideal-MHD stability code CAS3D. This formulation uses magnetic coordinates and does not involve any derivatives across magnetic surfaces. In addition to the expected Doppler shift of frequencies, properties of the spectrum of the ideal MHD force operator, which are already known for tokamaks, but now also shown in the stellarator case, are: firstly, the appearance of unstable flow-induced continua stemming from the coupling of sound and Alfvén continuum branches with equal mode numbers; and, secondly, the existence of flow-induced, global, stable modes near extrema of sound continuum branches, the extrema, in turn, being generated by the influence of a sheared flow on the static sound continua.
Systematic oxygen impurity reduction in smooth N-polar GaN by chemical potential control
Authors: Szymanski Dennis , Wang Ke , Kaess Felix , Kirste Ronny , Mita Seiji , Reddy Pramod , Sitar Zlatko , Collazo Ramon 
Published: November 2021

Abstract
Process chemical potential control and dislocation reduction were implemented to control oxygen concentration in N-polar GaN layers grown on sapphire substrates via metal organic chemical vapor deposition (MOCVD). As process supersaturation was changed from ∼30 to 3400, the formation energy of the oxygen point defect increased, which resulted in a 25-fold decrease in oxygen incorporation. Reducing dislocations by approximately a factor of 4 (to ∼109 cm−3) allowed for further reduction of oxygen incorporation to the low-1017 cm−3 range. Smooth N-polar GaN layers with low oxygen content were achieved by a two-step process, whereas first a 1 µm thick smooth N-polar layer with high oxygen concentration was grown, followed by low oxygen concentration layer grown at high supersaturation.
Six-fold symmetry origin of Dirac cone formation in two-dimensional materials
Authors: Qin Xuming , Liu Yi , Li Xiaowu , Yang Gui , Zhao Dongqiu , Ju Lin 
Published: November 2021

Abstract
Dirac materials possess many excellent electrical properties, resulting that the search and design of Dirac materials have become a hot research area. Revealing the formation conditions of Dirac cone (DC) can provide theoretical guidance for the search and design of Dirac materials. To obtain the necessary conditions for the formation of DC of two-dimensional (2D) materials with six-fold symmetry (SFS), the DC formation mechanism was analyzed by the ‘divide-and-couple’ approach in the framework of tight-binding theory, confirmed by the subsequent density functional theory calculations. The simple ‘6n + 2’ rule was proposed to determine whether the 2D materials with SFS have DCs, i.e. when the number of atoms in a unit cell is 6n + 2, the systems would possess DCs at the vertex of Brillouin zone for the 2D materials composed of the elements of the IV main group. Moreover, the ‘3n + 1’ rule was derived as the condition for the DC formation in graphene-like silagraphene with SFS and used to design a silagraphene Si6C8 with DCs. Understanding the DC formation mechanism of 2D materials with SFS not only provides theoretical guidance for designing novel Dirac materials but also sheds light on the symmetry origin of the formation mechanism of DC.
Theoretical aspects of radium-containing molecules amenable to assembly from laser-cooled atoms for new physics searches
Authors: Fleig Timo , DeMille David 
Published: November 2021

Abstract
We explore the possibilities for a next-generation electron-electric-dipole-moment experiment using ultracold heteronuclear diatomic molecules assembled from a combination of radium and another laser-coolable atom. In particular, we calculate their ground state structure and their sensitivity to parity- and time-reversal (

P
,
T

) violating physics arising from flavor-diagonal charge-parity (

CP

) violation. Among these species, the largest

P
,
T

-violating molecular interaction constants—associated for example with the electron electric dipole moment—are obtained for the combination of radium (Ra) and silver (Ag) atoms. A mechanism for explaining this finding is proposed. We go on to discuss the prospects for an electron EDM search using ultracold, assembled, optically trapped RaAg molecules, and argue that this system is particularly promising for rapid future progress in the search for new sources of

CP

violation.
Calculation of flow separation in a retarded boundary-layer over a moving continuous sheet
Authors: Mehmood Ahmer , Shah Babar Hussain , Usman Muhammad , Raza Iqrar 
Published: November 2021

Abstract
Theoretical investigations of fundamental boundary-layer flows are always given prime importance in the field of boundary-layer theory. In particular, among the boundary-layer flows occurring on planner geometries, importance had been given to the flows occurring over the surfaces of finite length. The boundary-layer flows due to moving continuous surfaces were introduced about half a century later to the famous Blasius flow. Unfortunately, no significant attention had been given to these flows with regard to the investigation of boundary-layer properties in these flows. Consequently, a great gap has been created between these two important categories of boundary-layer flows. It is a matter of fact that the flows due to moving continuous surfaces are richer in physics; offer favorable impact, and involve interesting technological applications. One of the important hallmarks of these flows is that they offer a significantly increased wall skin-friction as compared to the flows over surfaces of finite length. Therefore these flows appear to be profitable in situations that are more vulnerable to flow separation. To explore this fact the current study considers a variety of retarded wall velocities to calculate the delay in flow separation for the flows due to moving continuous surfaces in comparison to those occurring on a surface of finite length. It is observed that in the flows due to a moving continuous surface the flow separation is greatly delayed in comparison to the flows over surfaces of finite length. Moreover, the role of wall suction velocity, in this regard, is to be further amplified in these flows. Overall, it is concluded that the continuous surfaces are more useful in order to delay flow separation as compared to the surfaces of finite length.
Effect of point defects and nanopores on the fracture behaviors in single-layer MoS2 nanosheets
Authors: Bao Hongwei , Miao Yaping , Ma Fei 
Published: November 2021

Abstract
Point defects and nanopores are inevitable and particularly noticeable in single-layer (SL) MoS2. Molecular dynamics (MD) simulations have been done to comprehensively study the influences of point defects and nanopores on tensile deformation behaviors of SLMoS2 nanosheets, and the dependences of fracture properties on defect type and concentration, pore size, temperature and strain rate are discussed. The formation energy of S vacancy (VS) is the lowest one, but that of VMoS6 is the highest one, corresponding to the highest and lowest fracture stress, respectively. The local stress concentration around point defects and nanopores might lead to the early bond breaking and subsequent nucleation of cracks and brittle fracture upon tensile loading. A modified Griffith criterion is proposed to describe the defect concentration and pore size dependent fracture stress and strain. These findings provide us an important guideline for the structural design of 2D materials in future applications.
SAMBA controls cell division rate during maize development
Authors: Gong Pan , Bontinck Michiel , Demuynck Kirin , De Block Jolien , Gevaert Kris , Eeckhout Dominique , Persiau Geert , Aesaert Stijn , Coussens Griet , Van Lijsebettens Mieke , Pauwels Laurens , De Jaeger Geert , Inzé Dirk , Nelissen Hilde 
Published: November 2021

Abstract
SAMBA has been identified as a plant-specific regulator of the anaphase-promoting complex/cyclosome (APC/C) that controls unidirectional cell cycle progression in Arabidopsis (Arabidopsis thaliana), but so far its role has not been studied in monocots. Here, we show the association of SAMBA with the APC/C is conserved in maize (Zea mays). Two samba genome edited mutants showed growth defects, such as reduced internode length, shortened upper leaves with erect leaf architecture, and reduced leaf size due to an altered cell division rate and cell expansion, which aggravated with plant age. The two mutants differed in the severity and developmental onset of the phenotypes, because samba-1 represented a knockout allele, while translation re-initiation in samba-3 resulted in a truncated protein that was still able to interact with the APC/C and regulate its function, albeit with altered APC/C activity and efficiency. Our data are consistent with a dosage-dependent role for SAMBA to control developmental processes for which a change in growth rate is pivotal.
How Decompression Surgery Improves the Lower Back Pain in Patient with Lumbar Degenerative Stenosis
Authors: Yagi Mitsuru , Suzuki Satoshi , Nori Satoshi , Takahashi Yohei , Tsuji Osahiko , Nagoshi Narihito , Nakamura Masaya , Matsumoto Morio , Watanabe Kota 
Published: November 2021

Study Design.
Multicenter retrospective case series of patients treated surgically for lumbar spinal stenosis (LSS)

Objective.
We investigated how laminectomy improves lower back pain (LBP) and the factors associated with poor improvement.

Summary of Background Data.
Lumbar laminectomy is effective for alleviating neurological symptoms caused by LSS, whereas its effect on LBP is still controversial.

Methods.
A retrospective review of prospectively collected data from 436 patients (age 72 yrs, 69% males) who underwent laminectomy for LSS with 2 years of follow-up. We analyzed the following risk factors for residual LBP by uni- and multivariate analyses: age, sex, smoking, occupation, comorbidities, frailty, joint replacement, vertebral fracture, DISH, HRQOL, complications, and the presence of spinal instability. The LBP of male and female patients was analyzed after propensity score matching of known confounders. Patient-reported outcomes (JOABPEQ and VAS scores) were obtained at baseline and the 2-year postoperative follow-up.

Results.
LBP was significantly improved at 2 years post operation (VAS change 2.3 [95% CI 2.0–2.6], P < 0.01). Fifty-five percent of the patients achieved an MCID, with 67% having no or mild LBP. In the multivariate analysis, sex and baseline LBP were independent risk factors (female: OR 1.9 [1.2–3.0], baseline LBP [VAS≥7.5]: OR 1.9 [1.2–3.1]). Furthermore, the independent risk factors for severe baseline LBP were sex and mental status (female: OR 1.7 [1.1–2.7], P = 0.03, mental status: OR 3.8 [2.4–6.0], P < 0.01). However, an analysis of 102 pairs of propensity-score-matched male and female patients showed no difference in the improvement of LBP (male vs. female: VAS 3.8 ± 2.8 vs. 4.0 ± 2.9, P = 0.61, VAS change 3.1 ± 2.9 vs. 2.7 ± 3.0, P = 0.38).

Conclusion.
Decompression surgery for LSS significantly improved LBP. Sex and baseline LBP were risk factors for residual LBP. However, when males and females were matched by confounders, no difference was found in the LBP after surgery. Patients with severe baseline LBP may need further evaluation for their mental status because these patients are likely to have mental problems that potentially contribute to persistent LBP.

Level of Evidence: 4