bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bayesian evaluation of residual production cross sections in proton-induced nuclear spallation reactions
Authors: Peng Dan , Wei Hui-Ling , Chen Xi-Xi , Wei Xiao-Bao , Wang Yu-Ting , Pu Jie , Cheng Kai-Xuan , Ma Chun-Wang 
Published: May 2022

Abstract
Residual production cross sections in spallation reactions are key data for nuclear physics and related applications. Spallation reactions are very complex due to the wide range of incident energies and abundant fragments involved. Therefore, it is challenging to obtain accurate and complete energy-dependent residual cross sections. With the guidance of a simplified EPAX formula (sEPAX), the Bayesian neural network (BNN) technique is applied to form a new machine learning model (BNN + sEPAX) for predicting fragment cross sections in proton-induced nuclear spallation reactions. Three types of sample dataset for measured residual production cross sections in proton-induced nuclear spallation reactions are made, i.e. D1 consists of isotopic cross sections in reactions below 1 GeV/u, D2 consists of fragments excitation functions of reactions up to 2.6 GeV/u, and D3 is a hybrid of D1 and D2. With the constructed BNN and BNN + sEPAX models, the isotopic and mass cross section distributions are compared for the 356 MeV/u 40Ca + p and 1 GeV/u 136Xe + p reactions, and fragment excitation functions in 40Ca + p, 56Fe + p, 138Ba + p and 197Au + p reactions. It is found that the BNN model needs sufficient information to achieve good extrapolations, while the BNN + sEPAX model performs better extrapolations based on less information due to the physical guidance of the sEPAX formulas. It is suggested that the BNN + sEPAX model provides a new approach to predict the energy-dependent residual production cross sections produced in proton-induced nuclear spallation reactions of incident energies from tens of MeV/u up to several GeV/u.
Impurity screening and Friedel oscillations in Floquet-driven two-dimensional metals
Authors: Asmar Mahmoud M , Tse Wang-Kong 
Published: May 2022

Abstract
We develop a theory for the non-equilibrium screening of a charged impurity in a two-dimensional electron system under a strong time-periodic drive. Our analysis of the time-averaged polarization function and dielectric function reveals that Floquet driving modifies the screened impurity potential in two main regimes. In the weak drive regime, the time-averaged screened potential exhibits unconventional Friedel oscillations with multiple spatial periods contributed by a principal period modulated by higher-order periods, which are due to the emergence of additional Kohn anomalies in the polarization function. In the strong drive regime, the time-averaged impurity potential becomes almost unscreened and does not exhibit Friedel oscillations. This tunable Friedel oscillations is a result of the dynamic gating effect of the time-dependent driving field on the two-dimensional electron system.
Metadynamics molecular dynamics and isothermal Brownian-type molecular dynamics simulations for the chiral cluster Au18
Authors: Lim C C , Lai S K 
Published: May 2022

Abstract
In an effort to gain insight into enantiomeric transitions, their transition mechanism, time span of transitions and distribution of time spans etc, we performed molecular dynamics (MD) simulations on chiral clusters Au10, Au15 and Au18, and found that viable reaction coordinates can be deduced from simulation data for enlightening the enantiomeric dynamics for Au10 and Au15, but not so for Au18. The failure in translating the Au18-L ⇌ Au18-R transitions by MD simulations has been chalked up to the thermal energy k
B
T at 300 K being much lower than energy barriers separating the enantiomers of Au18. Two simulation strategies were taken to resolve this simulation impediment. The first one uses the well-tempered metadynamics MD (MMD) simulation, and the second one adeptly applies first a somewhat crude MMD simulation to locate a highly symmetrical isomer Au18S and subsequently employed it as initial configuration in the MD simulation. In both strategies, we work in collective variable space of lower dimensionality. The well-tempered MMD simulation tactic was carried out aiming to offer a direct verification of Au18 enantiomers, while the tactic to conduct MMD/MD simulations in two consecutive simulation steps was intended to provide an indirect evidence of the existence of enantiomers of Au18 given that energy barriers separating them are much higher than ca. k
B
T at 300 K. This second tactic, in addition to confirming indirectly Au18-L and Au18-R starting from the symmetrical cluster Au18S, the simulation results shed light also on the mechanism akin to associative/nonassociative reaction transitions.
Metal nanoparticle arrays via a water-based lift-off scheme using a block copolymer template
Authors: Landeke-Wilsmark Björn , Hägglund Carl 
Published: May 2022

Abstract
Metal nanoparticles (NPs) can exhibit unique electronic, magnetic, optical, and catalytic properties. Highly ordered, dense arrays of non-close-packed, surface-supported metal NPs are thus of potential use in a wide range of applications. Implementing such arrays over large surfaces can, however, be both technologically challenging and prohibitively expensive using conventional top-down nanofabrication techniques. Moreover, many existing patterning methods are too harsh for sensitive substrate surfaces and their applications. To address this, we here investigate a fabrication protocol involving a water-based lift-off scheme in which the template pattern generation is rapidly and inexpensively achieved through block copolymer (BCP) self-assembly. A three-layer lift-off stack consisting of, from top to bottom, a poly(styrene-block-2-vinyl pyridine) template, a SiO
x
intermediate hardmask, and a water-soluble poly(vinyl alcohol) sacrificial layer is employed in this endeavor. Solvent-induced surface reconstruction (SISR) is used to generate an initial surface topography in the BCP template which is subsequently transferred to the layers beneath in a sequence of reactive ion etching steps. Through judicious selection of stack materials and dry etch chemistries, a layered, high-aspect-ratio, nanoporous mask is thus implemented. After metal deposition, the mask and excess material are simply removed in a lift-off step by dissolving the bottommost sacrificial layer in water. The incorporation of an intermediate hardmask and a water-soluble sacrificial layer obviates the need for harmful and/or corrosive lift-off solvents and decouples the BCP self-assembly process from the influence of substrate properties. We demonstrate the generation of well-ordered arrays of Au NPs capable of supporting sharp, localized surface plasmon resonances. We also investigate improvements to large-scale uniformity, as this is found sensitive to the SISR termination step in the original protocol. Extensions of the technique to other BCP morphologies and materials deposited ought to be straightforward.
Chemical imaging of oxide confinement layers in

GaAs/AlxGa1−xAs

VCSELs
Authors: Mokhtari Merwan , Pagnod-Rossiaux Philippe , Levallois Christophe , Pofelski Alexandre , Laruelle François , Botton Gianluigi A , Landesman Jean-Pierre 
Published: May 2022

Abstract
The authors have studied the lateral oxidation of

Al

x

Ga

1
−
x

As

layers buried in vertical-cavity surface-emitting lasers using cross-sectional scanning transmission electron microscopy coupled with electron energy loss spectroscopy. Chemical maps and composition profiles of the oxidized AlO
x
layers have been produced. The sensitivity is such that trace compositions of a few % As and Ga can be detected in the AlO
x
with a spatial resolution of a few nanometers on the recorded chemical maps. To demonstrate the performance of the mapping technique, we compare results from an area in the vertical-cavity surface-emitting laser (VCSEL) which is pure

Al

x

Ga

1
−
x

As

to an oxidized area. These measurements are performed on a thin sample prepared by the focused ion beam technique within an actual VCSEL, which makes the mapping technique applicable for degradation investigations in devices at different stages of their lifetime. More generally, this measurement method is effective for detailed evaluation of AlO
x
layers and their fabrication process.
Improvement of thermal resistance in InGaAs/GaAs/AlGaAs microdisk lasers bonded onto silicon
Authors: Zubov F I , Moiseev E I , Nadtochiy A M , Fominykh N A , Ivanov K A , Makhov I S , Dragunova A S , Maximov M V , Vorobyev A A , Mozharov A M , Mintairov S A , Kalyuzhnyy N A , Gordeev N Yu , Kryzhanovskaya N V , Zhukov A E 
Published: May 2022

Abstract
Epi-side down bonding on a silicon substrate of AlGaAs/GaAs microdisk lasers is presented. A heterostructure with coupled large optical cavities enables location of an InGaAs quantum dot active region at a distance of ∼1 µm from the heterostructure surface. The thermal resistance was reduced to 0.2 and 0.1 K mW−1 for disks of 30 and 50 µm in diameter, respectively. The maximum continuous-wave power limited by the thermal rollover is more than doubled after bonding.
A novel multi-channel silicon-based piezoelectric micropump with active piezoelectric valve array
Authors: Peng Yun-Hao , Wang Dai-Hua 
Published: May 2022

Abstract
In order to only use one piezoelectric micropump to simultaneously drive and control multi-channel flow fluids of complex microfluidic systems in biological, chemical and medical applications, and then improve the integration and reduce the size of systems, principle and structure of a multi-channel silicon-based piezoelectric micropump with active piezoelectric valve array are proposed and realized. The micropump is composed of one pumping unit and four active piezoelectric valves with annular boundaries, which form active piezoelectric valve array by uniformly distributing around pumping unit. All valves are connected to pumping unit by corresponding fluid channels and they can realize bidirectional fluid flowing. Therefore, pump can suck fluid from any one or more valves through pumping unit and can discharge fluid to the other one or more valves, which form its six working modes. Silicon-based pump body is processed by photoetching and the micropump is fabricated by fixing circular piezoelectric unimorph actuators on the silicon-based pump body. Flow rate model is established, the flow characteristics under each working mode are experimentally tested. Results show that the micropump can realize simultaneously multi-channel fluid input and output, when it works under three-in and single-out, it has the maximum flow rate and output pressure; the flow rate model can predict its flow rate, the maximum relative error between experimental test result and numerical simulation result is 9.99%; the micropump has high flow control accuracy, when amplitude of driving voltage varies from 35 V to 36 V with step of 0.1 V, it has the minimum change of flow rate of 1 μL min−1, the maximum flow rate deviation of 5 μL min−1 and the maximum relative standard deviation of flow rate control of 0.175%. Therefore, the micropump provide feasible scheme for piezoelectric micropumps to be applied in complex microfluidic systems with multi-channel flow fluids, such as lab-on-chip.
Anderson localization in the Anderson–Hubbard model with site-dependent interactions
Authors: Nguyen T H Y , Le D A , Hoang A T 
Published: May 2022

Abstract
We consider Anderson localization in the half-filled Anderson–Hubbard model in the presence of either random on-site interactions or spatially alternating interactions in the lattice. By using dynamical mean field theory with the equation of motion method as an impurity solver, we calculate the arithmetically and geometrically averaged local density of states and derive the equations determining the critical value for the phase transition between metallic, Anderson and Mott insulating phases. The nonmagnetic ground state phase diagrams are constructed numerically. We figure out that the presence of Coulomb disorder drives the system toward the Anderson localized phase that can occur even in the absence of Anderson structural disorder. For the spatially alternating interactions, we find that the metallic region is reduced and the Anderson insulator one is enlarged with increasing interaction modulation. Our obtained results are relevant to current research in ultracold atoms in disordered optical lattices where metal–insulator transition can be observed experimentally by using ultracold atom techniques.
Cosmological constraints on sub-horizon scales modified gravity theories with MGCLASS II
Authors: Sakr Z. , Martinelli M. 
Published: May 2022

Abstract
In this paper we introduce a new public Einstein-Boltzmann
solver, MGCLASS II, built as a modification of the publicly
available CLASS code, that allows to obtain cosmological
observables in Modified Gravity theories. It implements several
commonly used parameterizations of deviations from General
Relativity, computing their impact on the growth of structure as
well as on the background evolution of the Universe, together with a
subset of available alternative theories, still not completely ruled
out by observations. MGCLASS II is built in such a way to
be compatible with parameter estimation codes such as
MontePython and Cobaya. We exploit this
possibility to constrain the parameterizations used by the Planck
collaboration, in order to validate the predictions of this new
code, and a newly implemented parameterization (z_flex) which has
different features. For the former we find good agreement with the
results existing in the literature, while we present original
constraints on the parameters of the latter, finding no significant
deviation from the standard cosmological model, ΛCDM.
Forward-backward asymmetries in

in the Bethe-Salpeter equation approach *
Authors: Liu Liang-Liang , Cui Su-Jun , Xu Jing , Guo Xin-Heng 
Published: May 2022

Abstract
Using the Bethe-Salpeter equation (BSE), we investigate the forward-backward asymmetries

in

in the quark-diquark model. This approach provides precise form factors that are different from those of quantum chromodynamics (QCD) sum rules. We calculate the rare decay form factors for

b and investigate the (integrated) forward-backward asymmetries in these decay channels. We observe the integrated

,

,

, and

; the hadron side asymmetries

; the lepton-hadron side asymmetries

; and the longitudinal polarization fractions

.
A Comparative Research of Thrust Simulation and Practice for the Small Solid Rocket Motor
Authors: Qin Xiaoyu , Shi Haoming , Wen Chunyu , Liu Shiyu 
Published: May 2022

Abstract
In practice, it is found that the simulation method applicable to the conventional size rocket motor cannot be directly applied to the design of the small rocket motor. Due to the change of size, the simulated thrust results differ greatly from the actual thrust results. In this paper, the tube grain and star grain are taken as examples to compare the simulated results with the actual experimental results. First, we determine a group of independent variables that can well reflect the changes of the main variables as a pretreatment and then use the zero dimensional interior ballistic algorithm for simulation. Finally, we design and conduct control experiments to draw a conclusion. The theoretical thrust was obtained by simulation and calculation, and the actual thrust was obtained by a lot of experiments. It was found that there were large offsets between the two types of grains, and the specific offsets corresponding to the two types of grains were obtained. The results show that there is a great difference between the simulated result and the actual result, which has a certain guiding significance for the design and research of small solid rocket motor.
Numerical simulations of sympathetic detonation of solid rocket motors
Authors: Pang Songlin , Chen Xiong , Xu Jinsheng 
Published: May 2022

Abstract
According to the numerical simulation, the sympathetic detonation of fiber composite shelled propellant was analyzed. Comparing the effects of fragments and reaction products shows that the impacting effect of fiber composite shell fragments is limited and can not lead the sympathetic detonation. The reason for sympathetic detonation in the closer distance is mainly reaction products.
Investigation into The Influences of Turbulence Models on Heating Prediction of Hypersonic Inflatable Aerodynamic Decelerator
Authors: Yang Hua , Ji Yi-min , Lin Jie , Chen Shu-sheng , Gao Zheng-hong 
Published: May 2022

Abstract
With the increasing demand for larger payloads for manned spaceflight and planetary exploration missions, hypersonic inflatable aerodynamic decelerator has gradually great application potentiality. The work presents the numerical simulations of hypersonic inflatable aerodynamic decelerator by the compressible Reynolds averaged Navier-Stokes equations with different turbulence models (such as SA, BSL, wilcox1988, SST). The pressure, eddy viscosity and heat flux under three Reynolds numbers (6.89E+6, 9.94E+6, 12.73E+6) are analyzed. The results demonstrate that the surface pressure distributions have slight difference, whereas the surface heating distributions appear remarkable diversity. In addition, compared with one equation turbulence model, two-equation turbulence models maybe more suitable for hypersonic heating predictions.
Iterative Guidance Algorithm for Lunar Soft Landing
Authors: Bojun Zhang , Zhanchao Liu 
Published: May 2022

Abstract
A closed-form explicit guidance algorithm for the deceleration, attitude adjustment and final landing phases before lunar probe soft landing is presented in this paper. Guidance with a variable-thrust engine is extended from the iterative guidance mode (IGM) to satisfy the terminal velocity, position, and attitude constraints. The closed form expression, obtained by integrating the acceleration and shutdown time, is analysed to obtain an explicit ex-pression for the velocity and position requirements and vertical touchdown of the spacecraft toward a designated landing site with high terminal accuracy. The influence of the attitude constraint on the motion equation is analysed to calculate the attitude, which is the physical control variable for the guidance loop. The variable thrust IGM formulation ensures the least switch of the thrust magnitude profile based on the analysis result of the residual flight altitude. The simulation results demonstrate that the proposed multi-constrained iterative guidance method can help accomplish an accurate lunar soft landing and that employed the algorithm is simple and easy to implement in engineering practice.
Continuous Integral Robust Roll Control for Single Moving- mass Controlled Reentry Vehicle
Authors: Zheng Jingzhong , Sergeevna Selezneva Maria 
Published: May 2022

Abstract
This paper concerns high-accuracy roll control for single moving-mass controlled reentry vehicle. Considering the simultaneous existence of matched and mismatched uncertainties in the reentry vehicle system, a continuous integral robust control strategy is proposed based on the backstepping design framework. The controller uses the error transformation method to transfer the mismatched modeling uncertainty to the control input channel, and then a robust structure constructed in the controller can handle it together with the matched modeling uncertainty. The final control input is continuously differentiable, which is benefit for tracking performance improvement and practical controller implementation. The proposed controller theoretically guarantees asymptotic tracking performance via Lyapunov analysis. Finally, simulation results are given to illustrate the efficiency of the proposed approach.
Influence of contact friction on static characteristics of multileaf bump foil bearing
Authors: Xu Ben , Zhang Jingyang 
Published: May 2022

Abstract
In order to reveal the influence mechanism of foil contact friction on the multi-leaf bump foil bearing performance, a deformation simulation model is established under the contact constraint of multi top foils and bump foils, and the analysis of the fluid-structure interaction is realized by combining with the Reynolds equation of compressible gas. The influence of the nonlinear variation of foil stiffness caused by contact friction on the static characteristics of the bearing under different bearing numbers is numerically analyzed. The results show: the foil stiffness increases nonlinearly with the foil deformation and presents the characteristic of circumferential non-uniformity. With the increase of the deformation of foil, the influence of friction coefficient on the foil stiffness is more significant. Within the parameters studied in this paper, the friction coefficient increases from 0 to 0.5, the bearing capacity increases first and then decreases when the bearing numbers is small; the bearing capacity increases monotonically when the bearing numbers is large, the higher the bearing numbers, the more significant the growth rate. The attitude angle increases with the increase of friction coefficient, and the bearing becomes more and more unstable. When the bearing numbers is large, we should pay more attention to the influence of friction on bearing performance. The computed model emphasizing nonlinear stiffness in this paper is close to the realities, and the results can provide guidance in the design of multi-leaf bump foil bearing.
Integrated Optimization of Aerodynamic and Electromagnetic Characteristics for Nozzle Central Cone
Authors: Zhang Saile , Yang Qingzhen , Wang Rui , Wang Xufei , Yang Haoqi 
Published: May 2022

Abstract
With the development and enhancement of anti-stealth technology and airborne radar, fighter jets will increasingly be threatened by the detection of airborne radar and ground-based radar. The exhaust system is a major radar scattering source in the backward direction of the aircraft due to its large open-ended property. A Radial-Based Function Neural Network Multi-Objective Particle Swarm Optimization (RBFNN-MOPSO) method is presented to reduce the nozzle’s radar cross section (RCS). Considering the geometric constraints and aerodynamic characteristics of the nozzle, 21 nozzle models with different types of cones are established by using uniform design (UD). The electromagnetic scattering characteristics of all the nozzles are simulated by Forward-Backward Iterative Physical Optics (FBIPO) method, and the Computational Fluid Dynamics (CFD) simulations have been conducted to obtain the flow field in the nozzle. After comprehensive evaluation and design by RBFNN-MOPSO, the mean value of RCS and thrust coefficient of the model have achieved good results. The process of optimization and design is proved to be effective and efficient for nozzle aerodynamic/electromagnetic integrated stealth design.
Primary research on influence of workpiece cooling on efficiency of Inconel’s 625 alloy elecrodischarge milling in carbon dioxide
Authors: Żyra A , Skoczypiec S 
Published: May 2022

Abstract
Inconel alloys one of the most cost intensive materials to machine with conventional machining methods. It is connected with its mechanical properties, as well as low thermal conductivity and also high material losses during machining. An alternative to conventional machining is electrodischarge machining (EDM), which enables to machine all the materials which are conductors or semi-conductors regardless its chemical composition and mechanical properties. There are three main dielectric types which can be used for EDM machining. The eco-friendly are gaseous ones. It is still hard to use gaseous dielectrics in the industrial applications, however it seems that this dielectrics are the future. The main aim of this research was to determine an influence of EDM milling in carbon dioxide used as dielectric in two configurations – with and without external workpiece cooling with deionized water on the EDM technological parameters (material removal rate, electrode wear) as well as technological surface integrity and surface structure.