bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vapor deposition rate modifies anisotropic glassy structure of an anthracene-based organic semiconductor
Authors: Bishop Camille , Bagchi Kushal , Toney Michael F. , Ediger M. D. 
Published: December 2021

We control the anisotropic molecular packing of vapor-deposited glasses of ABH113, a deuterated anthracene derivative with promise for future organic light emitting diode materials, by changing the deposition rate and substrate temperature at which they are prepared. We find that at substrate temperatures from 0.65 Tg to 0.92 Tg, the deposition rate significantly modifies the orientational order in the vapor-deposited glasses as characterized by x-ray scattering and birefringence. Both measures of anisotropic order can be described by a single deposition rate–substrate temperature superposition (RTS). This supports the applicability of the surface equilibration mechanism and generalizes the RTS principle from previous model systems with liquid crystalline order to non-mesogenic organic semiconductors. We find that vapor-deposited glasses of ABH113 have significantly enhanced density and thermal stability compared to their counterparts prepared by liquid-cooling. For organic semiconductors, the results of this study provide an efficient guide for using the deposition rate to prepare stable glasses with controlled molecular packing.
Bifurcations changing the homotopy type of the closure of an invariant saddle manifold of a surface diffeomorphism
Authors: Nozdrinova E. V. , Pochinka O. V. 
Published: December 2021

Abstract
It is well known from the homotopy theory of surfaces that an ambient isotopy does not change the homotopy type of a closed curve. Using the language of dynamical systems, this means that an arc in the space of diffeomorphisms that joins two isotopic diffeomorphisms with invariant closed curves in distinct homotopy classes must go through bifurcations. A scenario is described which changes the homotopy type of the closure of the invariant manifold of a saddle point of a polar diffeomorphism of a 2-torus to any prescribed homotopically nontrivial type. The arc constructed in the process is stable and does not change the topological conjugacy class of the original diffeomorphism. The ideas that are proposed here for constructing such an arc for a 2-torus can naturally be generalized to surfaces of greater genus.
Bibliography: 32 titles.
Disguised electromagnetic connections in classical electron theory
Authors: Boyer Timothy H 
Published: December 2021

Abstract
In the first quarter of the 20th century, physicists were not aware of the existence of classical electromagnetic zero-point radiation nor of the importance of special relativity. Inclusion of these aspects allows classical electron theory to be extended beyond its 19th century successes. Here we review spherical electromagnetic radiation modes in a conducting-walled spherical cavity and connect these modes to classical electromagnetic zero-point radiation and to electromagnetic scale invariance. Then we turn to the scattering of radiation in classical electron theory within a simple approximation. We emphasize that, in steady-state, the interaction between matter and radiation is disguised so that the mechanical motion appears to occur without the emission of radiation, even though the particle motion is actually driven by classical electromagnetic radiation. It is pointed out that, for nonrelativistic particles, only the harmonic oscillator potential taken in the low-velocity limit allows a consistent equilibrium with classical electromagnetic zero-point radiation. For relativistic particles, only the Coulomb potential is consistent with electrodynamics. The classical analysis places restrictions on the value of e
2/ℏc.
Study of notched MEMS specimen: elasto-plastic modeling and experimental testing
Authors: Somà Aurelio , Pistorio Francesca , Mubasher Saleem Muhammad 
Published: December 2021

Abstract
This paper investigates the effect of stress and strains concentration, due to the notch presence, on the elasto-plastic behavior of gold microstructures subjected to tensile loading under electrostatic actuation. A kinematic model for the test microstructure which relates the experimentally measured deflection to the induced stress in the central specimen with applied electrostatic load is developed. The local maximum stress and strains at the notch root are analytically estimated using the Neuber’s rule and verified through a detailed non-linear coupled-field electric-structural finite element method (FEM)-based analysis. Several experimental tests are carried out to analyze the accumulation of plastic strain and the consequent development of plastic hinges induced in the central notched specimen due to repeated cyclic tensile loading by measuring the corresponding deflection with each loading cycle. The comparison between the failure condition observed experimentally in the test notched specimens and the FEM-based simulation results shows that the notch acts as stress and strains raiser fostering the initiation and expansion of plastic hinges in the thin film gold specimen which can lead to the specimen breakdown.
Soft x-ray spectra of cerium laser-produced plasmas
Authors: White Elgiva , O’Sullivan Gerry , Dunne Padraig 
Published: December 2021

Abstract
Spectra of laser-produced plasmas of cerium have been recorded in the 1.5 to 15.5 nm spectral region. The plasmas were formed using the frequency doubled pulsed output of a neodymium-doped yttrium aluminium garnet (Nd:YAG) laser at 532 nm. At the power densities incident on-target, ranging from 8.6 × 109–2.1 × 1013 W cm−2, Ce4+ to Ce27+ ions gave rise to emission from Δn = 0, 1 transitions to final states where n = 4. The spectra are dominated by an intense unresolved transition array (UTA) in the 8–10 nm region arising from n = 4 to n = 4 transitions. Two distinct components of this UTA are observed whose appearance is strongly dependent on laser power density, corresponding to transitions involving ions with open 4d and open 4f subshells, the latter at longer wavelengths. Multiple other transition arrays are identified and UTA statistics are given. The analysis was aided by atomic structure calculations and the use of a steady state collisional-radiative model.
Calculated electron impact ionisation fragmentation patterns
Authors: Graves Vincent , Cooper Bridgette , Tennyson Jonathan 
Published: December 2021

Abstract
There are many measurements and calculations of total electron impact ionisation cross sections. However, many applications, particularly in plasma physics, also require fragmentation patterns. Approximate methods of deducing partial cross sections are tested based on the use of total cross section computed within the well-used binary encounter Bethe approximation. Partial ionisation cross sections for three series of molecules including CH4, CF4 and CCl4; SiH4 and SiCl4; NH3 and PH3, were estimated using two methods. Method one is semi-empirical and uses mass spectroscopy data to fix the partial cross sections at a single electron energy. The second is a fully computational method proposed by Huber et al (2019 J. Chem. Phys.
150 024306). Comparisons with experimental results suggest that the mass spectroscopy method is more accurate. However, as Huber’s method requires no experimental input, this method could be used as a first approximation when no experimental data is available. As mass spectroscopy sometimes provides incomplete datasets, a hybrid method based on the use of both methods is also explored.
Dynamics and 2D temperature distribution of plasma obtained by femtosecond laser-induced breakdown
Authors: Hossain Afaque M , Ehrhardt Martin , Rudolph Martin , Kalanov Dmitry , Lorenz Pierre , Zimmer Klaus , Anders André 
Published: December 2021

Abstract
Recently, plasma produced by focusing femtosecond laser in gases has been introduced as an etching tool in materials processing. Proper control of the plasma in this application necessitates the apt understanding of the different morphological features of the plasma. In this contribution we show that, the plasma produced in air goes through several stages of morphological development–from ellipsoidal to spherical to toroidal plasma, whereas in argon, axial compression of an ellipsoidal plasma is observed. To explain this dissimilarity, we have quantified the temperature by emission spectroscopy (Planck analysis with Wien’s approximation). The evolution of temperature shows a triple exponential dependence in time which can be correlated with different stages of morphological changes of the plasma. Open Source Field Operation and Manipulation simulations using experimentally determined temperature values show that—(i) the reverse pressure gradient propagates radially inwards and compresses the plasma in both air and argon and forms a localized high pressure zone at the center that generates a secondary pressure wave in air, but not in argon, and (ii) the baroclinic torque that is generated because of the Richtmyer–Meshkov instability, dominates the rate of vorticity in air, whereas effects of flow compressibility and velocity gradients dominate the vortices in argon. Knowledge of the initial state and the dynamics of the subsequent stages of the plasma formation can be utilized for control and optimization of laser-induced plasma applications.
A nonlinear magneto-elastoplastic coupling model based on Jiles–Atherton theory of ferromagnetic materials
Authors: Hu Xiangyi , Bu Yang , Zhang Jianhua 
Published: December 2021

Abstract
As seen in the Jiles–Atherton (J–A) model and its modified form, the linear relationship between the magnetization coefficient and the stress deviates significantly from the experimental results. It is necessary to introduce many parameters that are difficult to obtain or unknown to describe the effect of elastoplastic deformation on magnetization or hysteresis, such as shape coefficient, pinning coefficient, and molecular field coefficient. In this paper, a new nonlinear magneto-elastoplastic model for ferromagnetic materials is established based on the magneto-mechanical coupling effect, and both the sixth-order term of magnetization and the nonlinear equation of the magnetization coefficient are introduced into the magnetostriction equation. In the models established in this paper, the elastoplastic deformation equivalent magnetic field is introduced into the effective magnetic field, and the Frohlich–Kennelly equation is used to describe the anhysteretic magnetization. After comparing the prediction results of different models with the available experimental results, it is observed that the proposed model in this paper exhibits superior prediction ability for magnetostrictive strain, magnetization, and hysteresis phenomena under different stresses. This paper has also analyzed the mechanism of the effect of elasto-plastic loading and residual stress on the hysteresis in different models as well as the differences between them. The determination coefficient of the proposed model in this paper is closer to 1, which is better than the existing models, indicating that it has a better fitting effect and is of great significance to the development of quantitative non-destructive testing technology.
Continuous and discrete symmetries of renormalization group equations for neutrino oscillations in matter
Authors: Zhou Shun 
Published: December 2021

Abstract
Three-flavor neutrino oscillations in matter can be described by three effective neutrino masses

m

~

i

(for i = 1, 2, 3) and the effective mixing matrix V

αi
(for α = e,μ, τ and i = 1, 2, 3). When the matter parameter

a
≡
2

2

G

F

N

e

E

is taken as an independent variable, a complete set of first-order ordinary differential equations for

m

~

i

2

and |V

αi
|2 have been derived in the previous works. In the present paper, we point out that such a system of differential equations possesses both the continuous symmetries characterized by one-parameter Lie groups and the discrete symmetry associated with the permutations of three neutrino mass eigenstates. The implications of these symmetries for solving the differential equations and looking for differential invariants are discussed.
Assessment of secondary neutrons in particle therapy by Monte Carlo simulations
Authors: Vedelago José , Geser Federico A , Muñoz Iván D , Stabilini Alberto , Yukihara Eduardo G , Jäkel Oliver 
Published: December 2021

Abstract

Objective. The purpose of this study is to estimate the energy and angular distribution of secondary neutrons inside a phantom in hadron therapy, which will support decisions on detector choice and experimental setup design for in-phantom secondary neutron measurements. Approach. Dedicated Monte Carlo simulations were implemented, considering clinically relevant energies of protons, helium and carbon ions. Since scored quantities can vary from different radiation transport models, the codes FLUKA, TOPAS and MCNP were used. The geometry of an active scanning beam delivery system for heavy ion treatment was implemented, and simulations of pristine and spread-out Bragg peaks were carried out. Previous studies, focused on specific ion types or single energies, are qualitatively in agreement with the obtained results. Main results. The secondary neutrons energy distributions present a continuous spectrum with two peaks, one centred on the thermal/epithermal region, and one on the high-energy region, with the most probable energy ranging from 19 up to 240 MeV, depending on the ion type and its initial energy. The simulations show that the secondary neutron energies may exceed 400 MeV and, therefore, suitable neutron detectors for this energy range shall be needed. Additionally, the angular distribution of the low energy neutrons is quite isotropic, whereas the fast/relativistic neutrons are mainly scattered in the down-stream direction. Significance. It would be possible to minimize the influence of the heavy ions when measuring the neutron-generated recoil protons by selecting appropriate measurement positions within the phantom. Although there are discrepancies among the three Monte Carlo codes, the results agree qualitatively and in order of magnitude, being sufficient to support further investigations with the ultimate goal of mapping the secondary neutron doses both in- and out-of-field in hadrontherapy. The obtained secondary neutron spectra are available as supplementary material.
Dynamics of ultrafast heated radiative plasmas driven by petawatt laser light
Authors: Sugimoto K , Iwata N , Sunahara A , Sano T , Sentoku Y 
Published: December 2021

Abstract
A relativistic petawatt laser light can heat a high Z metal above keV temperatures isochorically and ionize it almost fully. Copious hard x-rays are emitted from a high-Z hot plasma, which acts as an x-ray source, while x-ray emissions serve as an energy sink for the plasma. The isochoric heating of a solid silver foil irradiated by a relativistic laser light is studied with the help of 1D and 2D particle-in-cell simulations including Coulomb collisions, ionizations, and radiation processes. We find that the radiation power from the keV silver plasma is comparable to the incident laser power when the laser intensity is less than 1019 W cm−2. Thus, the plasma formation and particle acceleration are affected by the radiation, e.g. a highly compressed shock formation. Once the laser heating is over, the silver plasma loses its energy on a timescale of picoseconds, during which hard x-rays flash. The radiation spectra of the keV silver plasma are also presented.
The physics of empty liquids: from patchy particles to water
Authors: Russo John , Leoni Fabio , Martelli Fausto , Sciortino Francesco 
Published: December 2021

Abstract
Empty liquids represent a wide class of materials whose constituents arrange in a random network through reversible bonds. Many key insights on the physical properties of empty liquids have originated almost independently from the study of colloidal patchy particles on one side, and a large body of theoretical and experimental research on water on the other side. Patchy particles represent a family of coarse-grained potentials that allows for a precise control of both the geometric and the energetic aspects of bonding, while water has arguably the most complex phase diagram of any pure substance, and a puzzling amorphous phase behavior. It was only recently that the exchange of ideas from both fields has made it possible to solve long-standing problems and shed new light on the behavior of empty liquids. Here we highlight the connections between patchy particles and water, focusing on the modelling principles that make an empty liquid behave like water, including the factors that control the appearance of thermodynamic and dynamic anomalies, the possibility of liquid–liquid phase transitions, and the crystallization of open crystalline structures.
Theoretical study of highly efficient CH3NH3SnI3 based perovskite solar cell with CuInS2 quantum dot
Authors: Gagandeep  , Singh Mukhtiyar , Kumar Ramesh , Singh Vinamrita , Srivastava Sunita 
Published: December 2021

Abstract
Simulation studies have been carried out for the n–i–p perovskite solar cell (PSC) structure i.e. ITO/SnO2/CH3NH3PbI3/CuInS2/Au. We have considered this cell as our primary structure and is simulated using solar cell capacitance simulator-1D software. Here, the CuInS2 quantum dot (CIS QD) acts as an inorganic hole transporting layer. Further, the use of the CIS QD in PSCs has been explored by simulating 20 different cell structures. These PSCs are based on recently used absorber layers, i.e. MASnI3, FAPbI3, and (FAPbI3)0.97 (MAPbBr1.5Cl1.5)0.03, and electron transporting layers, i.e. SnO2, TiO2, ZnO, C60, and IGZO. The performance of all structures has been optimized by varying the thickness of the absorber layers and electron transporting layers. The cell structure, ITO/SnO2/CH3NH3SnI3/CuInS2/Au, has been found to exhibit the highest power conversion efficiency of 21.79% as compared to other cells. Investigations have also been carried out to analyze the effect of defect density in the absorber layer and the interface of the cell structure. In addition, the cell performance has been ascertained by examining the impact of operating temperature, metal contact work function and that of resistance in series as well as in parallel. The simulation results of our primary cell structure are found to be in good agreement with the recent experimental study.
On the shear test of a MR elastomer under magnetic field applied at various angles
Authors: Dohmen Eike , Borin Dmitry 
Published: December 2021

Abstract
In this paper the influence of the angle between the applied external magnetic field and the mechanical shear direction on the measured elasticity of a magnetorheological (MR) elastomer is addressed. The whole range of magnetic field angles from 0∘ to 90∘ is analyzed in steps of 5∘. Though this dependence is of highest importance for practical applications this issue is rather neglected in previous studies. The work uses MR elastomer specimens based on a silicone rubber matrix containing iron powder in weight fractions of 82 and 89 wt.%. It has been shown that the measured modulus of elasticity of such composites decreases as the angle between an external magnetic field and applied shear deformation increases. As the framework for the discussion of the findings a macroscopic explanation associated with the magneto-deformation effect as well as an influence of the demagnetizing factor are considered.
Characterization of slide ring materials for dielectric elastomer actuators
Authors: Shintake Jun , Matsuno Koya , Kumegawa Shohei , Baba Kazumasa , Takeuchi Hiromitsu 
Published: December 2021

Abstract
This paper investigates the characteristics of sliding ring materials (SRMs), which are promising elastomeric materials for dielectric elastomer actuators (DEAs). Two different types of SRMs with Young’s modulus of 0.8 MPa and 3.3 MPa, respectively, are prepared, and their material and mechanical properties and electro-mechanical performances at electric fields of up to 30 V µm−1 are characterized. For comparison, the same tests are also performed on several commercially available elastomers: Elastosil 2030, Ecoflex 00-30, CF19-2186, and VHB 4905. The results reveal that SRMs demonstrate negligible Mullins effect and hysteresis, while their dielectric strength (62.4–112.4 V µm−1) and viscoelasticity (

tan
δ

0.07–0.24 at 10 Hz) are comparable or even superior to those of other elastomers. In addition, elongation at break is found to be 163.8%–172.1%. SRMs exhibit excellent electro-mechanical performance; for instance, one of the two types has an actuation force 293.2 mN at 24.9 V µm−1 and a strain of 5.2% at 22.3 V µm−1. These values are the largest or larger than most of the tested elastomers. The high performance of SRMs results from their dielectric constant, which ranges from 10.3 to 13.4, leading to an electro-mechanical sensitivity of up to 15.3 MPa−1. These results illustrate SRMs as attractive material options for DEAs.
Field-induced tricritical phenomenon and magnetic structures in magnetic Weyl semimetal candidate NdAlGe
Authors: Zhao Jun , Liu Wei , Rahman Azizur , Meng Fanying , Ling Langsheng , Xi Chuanying , Tong Wei , Bai Yuming , Tian Zhaoming , Zhong Yunbo , Hu Ying , Pi Li , Zhang Lei , Zhang Yuheng 
Published: December 2021

Abstract
Non-centrosymmetric NdAlGe is considered to be a candidate for magnetic Weyl semimetal in which the Weyl nodes can be moved by magnetization. Clarification of the magnetic structures and couplings in this system is thus crucial to understand its magnetic topological properties. In this work, we conduct a systematical study of magnetic properties and critical behaviors of single-crystal NdAlGe. Angle-dependent magnetization exhibits strong magnetic anisotropy along the c-axis and absolute isotropy in the ab-plane. The study of critical behavior with H∥c gives critical exponents β = 0.236(2), γ = 0.920(1), and δ = 4.966(1) at critical temperature T
C = 5.2(2) K. Under the framework of the universality principle, M(T, H) curves are scaled into universality curves using these critical exponents, demonstrating reliability and self-consistency of the obtained exponents. The critical exponents of NdAlGe are close to the theoretical prediction of a tricritical mean-field model, indicating a field-induced tricritical behavior. Based on the scaling analysis, a H–T phase diagram for NdAlGe with H∥c is constructed, revealing a ground state with an up-up-down spin configuration. The phase diagram unveils multiple phases including up-up-down domains, up-up-down ordering state, polarized ferromagnetic (PFM), and paramagnetic (PM) phases, with a tricritical point (TCP) located at the intersection [T
TCP = 5.27(1) K, H
TCP = 30.1(3) kOe] of up-up-down, PFM, and PM phases. The multiple phases and magnetic structures imply a delicate competition and balance between variable interactions and couplings, laying a solid foundation for unveiling topological properties and critical phenomena in this system.
Nonlinear dynamics in the jupiter magnetosphere: implications of dust-acoustic cnoidal mode
Authors: Tolba R E , Yahia M E , Moslem W M 
Published: December 2021

Abstract
Different types of waves and their nature in the Jovian middle magnetosphere are still not clear or specified. For this purpose, a generalized hydrodynamic model for an arbitrary amplitude dust-acoustic waves is built for true Jovian magnetosphere. The plasma system consists of positive dust grains, Maxwellian ions and electrons. An evolution equation containing a Sagdeev potential is derived, and its numerical analysis is presented. Unexpectedly, the given data yielded cnoidal waves only with positive potential. The effect of the external magnetic field, Mach number, and directional cosine parameters are studied and manipulated. We think that the present results are important in realizing the main waves in the Jovian magnetosphere, and the possible correlation to its particles’ stability and pole acoustic waves.