bluuebunny/crossref_metadata_2025 huggingface dataset:
Interface-resolved simulations of particles in active nematics
Authors: Phan-Thien Nhan
Published: June 2023

An accurate coarse-grained simulation of an active fluid is invaluable as a tool to understand its hydrodynamic behaviors. The study on the dynamics of particles immersed in an active fluid also requires accurate resolution of the fluid–particle interaction. In this paper, we propose a robust direct forcing fictitious domain method to study the dynamics of suspended particles in an active fluid modeled by “active nematics.” This method serves as both a coarse-grained approach and an accurate model of fluid–particle interaction. We first validate the method by computing the kinetic energy spectrum for the bulk active nematics and find that it accurately reproduces the scaling laws reported theoretically and experimentally. By utilizing these interface-resolved simulations, we illustrate that the model's activity parameter cannot be simply considered as the concentration of bacterial suspensions. Moreover, we find that the diffusion coefficient DT of an individual disk is relevant to the length scale lc of the active nematics, following a power-law scaling DT ∼ lc−1.5. Regarding collective dynamics, we discover a self-organized length scale of approximately 7.5 times the disk's diameter in the active nematics. Additionally, the disks modify the kinetic energy spectrum of the active nematics at both the self-organized length scale and the individual disk's diameter scale, respectively.
General form of axially symmetric stationary metric: exact solutions and conservation laws in vacuum fields
Authors: Jyoti Divya , Kumar Sachin
Published: June 2023

The invariant non-static solutions of Einstein’s vacuum field equations, corresponding to the most general form of axially symmetric stationary line element that represents a non conformally flat semi-Riemannian spacetime in cylindrical coordinates, are investigated. Lie symmetry method is used for symmetry reduction as well as for obtaining exact solutions in terms of arbitrary functions. The conservation laws are obtained for vacuum equations in axially symmetric gravitational fields. The solutions of Lewis metric and Chandrasekhar metric, are derived from the obtained solutions. By considering the possibilities of arbitrary functions, the graphical behaviour of the solutions is also shown.
A generic instability in clustering dark energy?
Authors: Hassani Farbod , Adamek Julian , Kunz Martin , Shi Pan , Wittwer Peter
Published: June 2023

In this paper, we study the effective field theory (EFT) of dark energy (DE) for the k-essence model beyond linear order. Using particle-mesh N-body simulations that consistently solve the DE evolution on a grid, we find that the next-to-leading order in the EFT expansion, which comprises the terms of the equations of motion that are quadratic in the field variables, gives rise to a generic instability in the regime of low speed of sound (high Mach number). We rule out the possibility of a numerical artefact by considering simplified cases in spherically and plane symmetric situations analytically. If the speed of sound vanishes exactly, the non-linear instability makes the evolution singular in finite time, signalling a breakdown of the EFT framework. The case of finite (but small) speed of sound is subtle, and the local singularity could be replaced by some other type of behaviour with strong non-linearities. While an ultraviolet completion may cure the problem in principle, there is no reason why this should be the case in general. As a result, for a large range of the effective speed of sound cs
, a linear treatment is not adequate.
Observables for cyclic causal set cosmologies
Authors: Dowker Fay , Zalel Stav
Published: June 2023

In causal set theory, cycles of cosmic expansion and collapse are modelled by causal sets with ‘breaks’ and ‘posts’ and a special role is played by cyclic dynamics in which the universe goes through perpetual cycles. We identify and characterise two algebras of observables for cyclic dynamics in which the causal set universe has infinitely many breaks. The first algebra is constructed from the cylinder sets associated with finite causal sets that have a single maximal element and offers a new framework for defining cyclic dynamics as random walks on a novel tree. The second algebra is generated by a collection of stem-sets and offers a physical interpretation of the observables in these models as statements about unlabelled stems with a single maximal element. There are analogous theorems for cyclic dynamics in which the causal set universe has infinitely many posts.
Triple interference, non-linear Talbot effect and gravitization of the quantum
Authors: Berglund Per , Geraci Andrew , Hübsch Tristan , Mattingly David , Minic Djordje
Published: June 2023

Recently we have discussed a new approach to the problem of quantum gravity in which the quantum mechanical structures that are traditionally fixed, such as the Fubini–Study metric in the Hilbert space of states, become dynamical and so implement the idea of gravitizing the quantum. In this paper we elaborate on a specific test of this new approach to quantum gravity using triple interference in a varying gravitational field. Our discussion is driven by a profound analogy with recent triple-path interference experiments performed in the context of non-linear optics. We emphasize that the triple interference experiment in a varying gravitational field would deeply influence the present understanding of the kinematics of quantum gravity and quantum gravity phenomenology. We also discuss the non-linear Talbot effect as another striking phenomenological probe of gravitization of the geometry of quantum theory.
Plasma-enhanced atomic layer deposition of nickel and nickel oxide on silicon for photoelectrochemical applications
Authors: O’Donnell S , O’Neill D , Shiel K , Snelgrove M , Jose F , McFeely C , O’Connor R
Published: June 2023

The production of hydrogen fuel through sunlight-driven water splitting has the potential to harness and store large quantities of solar energy in a clean and scalable chemical state, suitable for later use in a range of energy applications. Silicon (Si) possesses many of the required properties to be used effectively as a photoelectrochemical (PEC) water-splitting photoanode. However, its sensitivity to corrosion during the oxygen evolution reaction limits its performance in photoanode applications, thus requiring additional overlayer materials to protect the underlying Si substrate. Nickel oxide (NiO) is one material that acts as an effective protective layer, being transparent, suitably conductive and stable. In this work, we present NiO deposition via state-of-the-art atomic layer deposition and photoemission studies to grow and characterize NiO and Ni–metal protective films. Early-stage nucleation of deposited thin films is illustrated along with the effects of post-deposition annealing and argon milling on depth profile information. Previous reports on the effects of slow argon milling are explored and counter arguments are proposed. Protective films are subjected to PEC testing, which shows enhancement of stability and photocurrent output as a result of the deposited films and plasma annealing on these thin films.
DFT investigation of structural and optoelectronic properties of glassy chalcogenide CuXY2 (X = Sb, Bi; Y = S, Se, Te) molecules
Authors: Ranjan Prabhat , Balasubramanian Krishnan , Chakraborty Tanmoy
Published: June 2023

The structural, electronic, spectral and optical properties of the ternary semiconducting material CuXY2 (X = Sb, Bi; Y = S, Se, Te) are computed using the density functional theory (DFT) technique. The ground-state configurations show that these systems have distorted rhomboidal structures in singlet states. It is found that CuSbY2 possesses higher highest occupied molecular orbital (HOMO) – lowest unoccupied molecular orbital (LUMO) energy gap than CuBiY2. We have employed three different levels of theory (B3LYP/LANL2DZ, relativistic effective—core potentials—CRENBL++, LANL08+) to study the electronic states. The energy gaps of these materials vary from 1.926–2.183 eV and 1.862–2.340 eV, respectively, at different levels of theory, suggesting their suitability as solar cell absorbents. DFT-based global structural descriptors are computed and analyzed with the help of vertical ionization energy and vertical electron affinity. The optical properties, such as optical electronegativity, refractive index, dielectric constant and IR and Raman activity, are studied. Our results show that the optical electronegativity of CuSbY2 is higher than that of CuBiY2 whereas the refractive index of CuSbY2 is smaller than that of CuBiY2. The computed harmonic frequencies and maximum intensities of IR and Raman spectra decline from S to Se to Te for systems CuSbY2 and CuBiY2. Our computed electrostatic potentials and other electronic properties show that CuBiY2 systems differ substantially from CuSbY2 due to relativistic effects on Bi.
Characteristic excitonic absorption of MoSi2N4 and WSi2N4 monolayers
Authors: Liu Hongling , Huang Baibiao , Dai Ying , Wei Wei
Published: June 2023

As new members of the two-dimensional materials family, MoSi2N4 and WSi2N4 exhibit unique physical properties. However, their optical properties in consideration of spin–orbit coupling (SOC) have not been discussed. In this work, the excited-state properties of MoSi2N4 and WSi2N4 monolayers are studied by means of many-body perturbation theory in combination with first-principles calculations. We find that the quasiparticle correction leads to a large band gap renormalization of more than 1 eV for MoSi2N4 and WSi2N4 monolayers. Because of the SOC, characteristic A and B excitons form with large binding energies of about 1 eV. The excitation energy difference of A and B excitons can be used to well address the spin–valley splitting. MoSi2N4 shows more abundant excitons (A′, B′ and C excitons), turning out to be a promising candidate to explore intra- and inter-exciton transitions. The exciton wave function indicates that the low-energy excitons in MoSi2N4 and WSi2N4 monolayers are confined in the middle MoN2/WN2 layer, which is unfavorable for excitonic photocatalysis. On the other hand, the valley states based on excitons can be protected by SiN layers from both sides.
Structure and magnetism of the triangular lattice material YbBO3
Authors: Sala G , Stone Matthew B , Do Seung-Hwan , Taddei Keith M , Zhang Qiang , Halász Gábor B , Lumsden M D , May Andrew F , Christianson Andrew D
Published: June 2023

YbBO3 is a member of the orthoborate family of materials which contains a triangular arrangement of Yb3+ ions. Here we study the physical properties of YbBO3 with neutron diffraction, inelastic neutron scattering, specific heat, and ac susceptibility measurements. The neutron diffraction measurements confirm that our samples of YbBO3 crystallize in the monoclinic space group

C
2

/

c

(#15) which contains two crystallographically distinct Yb3+ sites decorating a slightly distorted triangular lattice. Heat capacity and ac susceptibility measurements indicate a potential transition to magnetic order at 0.4 K. In agreement with these observations, neutron diffraction measurements at 0.044 K observe magnetic Bragg peaks which can be indexed by a propagation vector of (0 0 1). Although determining a unique spin configuration corresponding to the observed magnetic Bragg peaks is not possible, model refinements indicate that the ordered moments are likely in the range of 0.4–0.9 

μ
B

and, notably, require moments on both Yb sites. In addition to the magnetic Bragg peaks, diffuse scattering at low Q is observed indicating that the transition does not correspond to complete long range magnetic order. The two-site picture for YbBO3 is further evidenced by the number of crystal field excitations observed by inelastic neutron scattering measurements. Together these results show that YbBO3 is a two-site triangular lattice material with signatures of long-range order as well as shorter ranged spin correlations.
Electrochemical testosterone biosensor based on pencil graphite electrode electrodeposited with copper oxide nanoparticles
Authors: Bozdoğan Betül
Published: June 2023

Accurately monitoring the blood levels of testosterone (TST) in a sensitive, simple, and rapid manner is of paramount importance for the diagnosis and treatment of various medical conditions, as well as for controlling pharmaceutical quality and facilitating doping detection. TST, the primary male sex hormone, plays a crucial role in facilitating human physical performance, protein synthesis, and the development of muscle mass. Consequently, TST and its analogues are frequently abused by athletes as performance-enhancing steroid in order to increase muscle mass and enhance their performance. The use of such steroids is strictly prohibited to guarantee fair play. In this study, we employed a pencil graphite electrode that was electrochemically modified with CuO nanoparticles (CuONPs) for determination of TST. The electrode response was significantly enhanced by approximately fourfold compared to the unmodified pencil graphite electrode (PGE) when electrodeposition CuONPs onto PGE surface was performed at a potential of −0.6 V for 200 s. The success of modification was confirmed through morphological analysis using scanning electron microscopy and energy-dispersive x-ray spectroscopy. Using square wave adsorptive stripping voltammetry analysis in Britton–Robinson buffer at pH 6.0, we demonstrated that the proposed sensor exhibited sensitivity to detect TST within a linear range of 5–200 nM. The detection limit of sensor was calculated 4.6 nM (1.32 ng ml−1). The sensor platform developed for the accurate, sensitive, and specific determination of TST holds tremendous potential for the development of point-of-care devices and their integration into lab-on-a-chip research.
Study of the pH effect on the optical and morphological properties of S, N self-doped carbon dots applied as fluorescent anti-counterfeiting ink and pH sensor
Authors: Nascimento Sendy Melissa Santos do , Sonsin Artur Falqueto , Barbosa Cintya D’ Angeles do E S , Fonseca Eduardo Jorge S
Published: June 2023

The pH value is an important parameter as it is part of several processes, whether environmental or biological. In this report, S, N self-doped carbon dots (CDs) were synthesized by a simple hydrothermal method using cysteine (cys) and citric acid as precursors for a detailed investigation of size, morphological, photoluminescent, and structural changes at different pH values and its use as pH sensor and fluorescent ink. The fluorescence intensity of cys-CDs was dependent on the pH, presenting a linear relationship with pH values in the range of 2.0–9.0. Using spectroscopic techniques, a mechanism for the pH-dependent fluorescence is proposed, based on the aggregation of cys-CDs and also protonation/deprotonation of surface functional groups that change the excited state. The cys-CDs were found to be efficient as fluorescent pH sensors using real samples (distilled water and tap water). Furthermore, the pH changes in cys-CDs can be used for the visual enhancement of anti-counterfeiting technologies. Thus, the results of this study show that cys-CDs can act as an efficient and pH sensitive fluorescent sensor, which can be used to measure the pH value of water samples, due to its high fluorescence intensity, and can be applied successfully as a fluorescent ink.
Determining the effect of cardiac blood volume on accuracy of uptake rate constants by simulation
Authors: Johnson L C , Guerraty M A , Moore S C , Metzler S D
Published: June 2023

Objective. There is great interest in better understanding coronary microvascular disease using mouse models. Typical quantification requires dynamic imaging to estimate the rate constant K
1 of the tracer moving from the blood into the myocardium. In addition to K
1, it is also desirable to determine blood volume fraction V, which if known allows for more accurate fitting of K
1. Our previously published kinetic modeling software did not consider the effect of V. To ensure a better fit of experimental data to the model for myocardial

μ

SPECT imaging, in this work we updated our kinetic modeling software to include a blood volume fraction V, which adds a fraction of the arterial activity concentration into the tissue concentration. Approach. The tissue and blood time-activity curves (TACs) used for fit input were generated using ideal equations with known values in MATLAB. This allowed post-fit results to be compared to known values to determine fit errors. Parameters that were varied in generating the TACs included blood volume fraction (0, 0.05, 0.1, 0.2 and 0.3), K
1 (0.5, 1.5, 2.5 ml min−1 g−1), frame length (1, 2, 5, 10, 15, 20 s), FWHM of the input Gaussian (10, 20, 40 s), and time of the injection peak relative to frame duration. Blood volume-fraction results have low error when blood volume is lowest, but results worsen as frame length and K
1 increase. Main results. We demonstrated that blood volume can be accurately determined, and also show how fit accuracy varies across TACs with different input properties. Significance. This information allows for robust use of the fitting algorithm and aids in understanding fit performance when used in animal studies.
Improvement of the hybrid approach between Monte Carlo simulation and analytical function for calculating microdosimetric probability densities in macroscopic matter
Authors: Sato Tatsuhiko , Matsuya Yusuke , Ogawa Tatsuhiko , Kai Takeshi , Hirata Yuho , Tsuda Shuichi , Parisi Alessio
Published: June 2023

Objective. Estimation of the probability density of the microdosimetric quantities in macroscopic matter is indispensable for applying the concept of microdosimetry to medical physics and radiological protection. The Particle and Heavy Ion Transport code System (PHITS) enables estimating the microdosimetric probability densities due to its unique hybrid modality between the Monte Carlo and analytical approaches called the microdosimetric function. It can convert the deposition energies calculated by the macroscopic Monte Carlo radiation transport simulation to microdosimetric probability densities in water using an analytical function based on the track-structure simulations. Approach. In this study, we improved this function using the latest track-structure simulation codes implemented in PHITS. The improved function is capable of calculating the probability densities of not only the conventional microdosimetric quantities such as lineal energy but also the number of ionization events occurring in a target site, the so-called ionization cluster size distribution, for arbitrary site diameters from 3 nm to 1 μm. Main results. The accuracy of the improved function was well verified by comparing the microdosimetric probability densities measured by tissue-equivalent proportional counters with the corresponding data calculated in this study. Test calculations for clonogenic cell survival using the improved function coupled with the modified microdosimetric kinetic model suggested a slight increase of its relative biological effectiveness compared with our previous estimations. As a new application of the improved function, we calculated the relative biological effectiveness of the single-strand break and double-strand break yields for proton irradiations using the updated PHITS coupled with the simplified DNA damage estimation model, and confirmed its equivalence in accuracy and its superiority in computational time compared to our previously proposed method based on the track-structure simulation. Significance. From these features, we concluded that the improved function could expand the application fields of PHITS by bridging the gap between microdosimetry and macrodosimetry.
Validity of ActivPAL CREA software detection of sitting and lying during free-living conditions
Authors: Shivgulam Madeline E , Frayne Ryan J , Schwartz Beverly D , Wu Yanlin , Daley W Seth , Kimmerly Derek S , O’Brien Myles W
Published: June 2023

Objective. Approaches to differentiate sitting and lying are available within the default activPAL software from a single thigh-worn monitor. Dual-monitor methods use multiple monitors positioned on the thigh and torso to characterize sitting versus lying. We evaluated the validity between these two methods to measure waking, sitting, and lying time in free-living conditions. We also examined if the degree-threshold distinguishing sitting/lying for the dual-monitor (<30° and <45°) impacted results. Approach. Thirty-five young adults (24 ± 3 years, 16 females) wore an activPAL 24 h per day on their thigh and torso during free-living conditions (average: 6.8 ± 1.0 d, 239 total). Data were processed using the default activPAL software (thigh-only) or a custom MATLAB program (dual-monitor). Main results. The single-monitor recorded less lying time (59 ± 99 min d−1) and more sitting time (514 ± 203 min d−1) than the dual-monitor method regardless of 30° (lying: 85 ± 94 min d−1; sitting: 488 ± 166 min d−1) or 45° lying threshold (lying: 170 ± 142, sitting: 403 ± 164 min d−1; all, p < 0.001). The single monitor lying time was weakly correlated to the dual-monitor (30°: ρ = 0.25, 45°: ρ = 0.21; both, p < 0.001), whereas sitting was moderate-strong (30°: ρ = 0.76, 45°: ρ = 0.58; both, p < 0.001). However, the mean absolute error was 81 min d−1 (30°) and 132 min d−1 (45°) for both lying and sitting. Significance. The method of differentiating sitting/lying from a single thigh-worn activPAL records more sitting time and less lying time compared to a dual-monitor configuration (regardless of degree-threshold) that considered the position of the torso. A further refinement of algorithms or implementation of multiple-monitor methods may be needed for researchers to derive detailed sedentary positions.
Critical assessment of the applicability of the Child-Langmuir law to plasma ion source extraction systems
Authors: Kosonen S T , Kalvas T , Toivanen V , Tarvainen O , Faircloth D
Published: June 2023

Applicability of the classical one-dimensional and the recently developed multi-dimensional Child-Langmuir (CL) laws to plasma ion source extraction systems is studied. Experiments with a filament-driven multicusp ion source using a simplified extraction system, and comprehensive simulations with two different software packages, suggest that ion beams, which are typically assumed to be space charge or CL limited, are actually divergence-limited. In addition, it was observed that the dynamic plasma meniscus and geometric effects of the extraction system have a greater impact on the ion beam behavior than the effects predicted by the multi-dimensional CL law. Nevertheless, it was found that ion beams produced by the ion source exhibit space charge limited behavior, the beam current scaling with the extraction voltage as

I
∝

V

3

/

2

, provided that the entire beam is measured and its divergence is kept small and constant for each extraction voltage. This implies that the applicability of the CL law on a specific extraction system cannot be resolved by a straightforward voltage sweep and beam current measurement but instead, the plasma parameters must be adjusted for each extraction voltage. By shifting the focus from the CL limited framework to the divergence-limited framework, a clearer interpretation of the beam current–voltage characteristics of extraction systems can be achieved. This shift in perspective may also lead to the development of new design paradigms that can further enhance the performance of plasma ion source extraction systems.
Detection of hydrated electrons in water-jet immersed in low-pressure plasma by laser-induced desolvation
Authors: Inagaki Yoshinobu , Sasaki Koichi
Published: June 2023

We detected hydrated electrons in a micrometer-size water jet immersed in a low-pressure plasma by laser-induced desolvation. When we irradiated the 2nd, 3rd, and 4th harmonics of Nd:YAG laser pulses to the water jet, we detected the pulsed current which indicated the transport of electrons from the water jet to the plasma. We observed a proportional relationship between the amplitude of the pulsed current and the laser energy, which is consistent with the conversion from hydrated to free electrons by laser-induced desolvation. The amplitude of the pulsed current increased with the negative bias voltage between the plasma and the water jet. The most remarkable result was found in the relationship between the photon energy and the quantum yield of the electron transport. The experimental quantum yield was orders of magnitude higher than that predicted by a Monte Carlo simulation in a low photon energy region, suggesting the possibility that hydrated electrons we detected in the present experiment have much lower hydration energies than well-known hydrated electrons.
On-demand tuning of mechanical stiffness and stability of Kresling origami harnessing its nonrigid folding characteristics
Authors: Li Zhen , Agarwal Vipin , Wang Liangmo , Wang K W
Published: June 2023

Being adaptive with respect to changing operating conditions and the environment is an imperative demand for advanced engineering structures. In this research, two Kresling origami units are stacked together to form an online and on-demand tunable dual-Kresling origami structure (D-KOS), allowing easy and significant change in the multistability profile and apparent stiffness without redesign. Specifically, by harnessing its nonrigid folding nature together with geometric characteristics, the D-KOS can be programmed to follow distinct paths of its strain energy contour as varying

ϕ
p

(rotational angle of the top plate of the D-KOS), which can be utilized to explicitly derive different mechanical properties. The D-KOS with identical Kresling origami units can exhibit various symmetric bistable behaviors with different energy barriers via adjusting

ϕ
p

. Such a structure becomes a monostable system as the tuning variable reaches a critical value. This change in the energy landscape and stability profile gives rise to a change in stiffness at its stable equilibria, which, as a result, creates a wide range of stiffness value one can achieve, including quasi-zero stiffness. Such tuning of

ϕ
p

 

does not require redesign of the structure and thus can achieve online and on-demand tailoring. To verify the concept, proof-of-concept prototypes are developed and utilized to validate the D-KOS’s mechanical tunability experimentally. Moreover, the different design parameters of the D-KOS can change its tunability. For example, the D-KOS with nonidentical Kresling origami units can possess even richer stability properties (being asymmetric bistable, symmetric bistable, and monostable) with various energy landscapes. In addition, one can also tailor the range of the adjustable stiffness by changing the design parameters, such as the ratio of the angle between the polygon side and the valley crease of the triangular facets, and the height of the Kresling origami unit.
Non-Markovianity in the time evolution of open quantum systems assessed by means of quantum state distance
Authors: Mouloudakis G , Stergou I , Lambropoulos P
Published: June 2023

We provide a quantitative evaluation of non-Markovianity (NM) for an XX chain of interacting qubits with one end coupled to a reservoir. The NM of several non-Markovian spectral densities is assessed in terms of various quantum state distance (QSD) measures. Our approach is based on the construction of the density matrix of the open chain, without the necessity of a master equation. For the quantification of NM we calculate the dynamics of the QSD measures between the Markovian-damped and various types of non-Markovian-damped cases. Since in the literature several QSD measures, appear in forms that imply trace preserving density matrices, we introduced appropriate modifications so as to render them applicable to the case of decaying traces. The results produce remarkable consistency between the various QSD measures. They also reveal a subtle and potentially useful interplay between qubit–qubit interaction and non-Markovian damping. Our calculations have also uncovered a surprisingly dramatic slowing-down of dissipation by the squared Lorentzian reservoir.
Condensation phases in a non-Hermitian optical lattices system
Authors: Zhang Xiao-Ru , Yang Shi-Jie
Published: June 2023

We explore the condensate phase of single-species bosons in an optical lattice through the use of dissipative Bose–Hubbard models. The ground state of system possesses a real-energy, which corresponds to non-Hermitian Hamiltonians with non-reciprocal hopping phase factors. Through the application of inhomogeneous dynamical Gutzwiller mean-field theory (DGMFT), we predict a fascinating phenomenon: the ground state displays a periodic arrangement of superfluid islands amidst a Mott insulator sea. Additionally, the number of superfluid islands is proportional to the spatial period squared.
Multiple silicon dangling-bond charge qubits for quantum computing: a Hilbert-space analysis of the Hamiltonian
Authors: Shaterzadeh-Yazdi Zahra , Kazemikhah Payman
Published: June 2023

Silicon-based dangling-bond charge qubit is one of the auspicious models for universal fault-tolerant solid-state quantum computing. In universal quantum computing, it is crucial to evaluate and characterize the computational Hilbert space and reduce the complexity and size of the computational space. Here, we recognize this problem to understand the complexity and characteristics of the Hilbert space in our dangling-bond qubit model. The size of the desired Hilbert space can prominently be reduced by considering assumptions regarding the qubit loss. Moreover, the dimension of the desired subsets in the space shrinks by a factor of two due to the spin preservation property. Finally, the required classical memory for storage of the qubit information, Hamiltonian and Hilbert space is analysed when the number of qubits grows.
Effect of rare earth oxide (Y2O3) addition on wear characteristic of TiB2 ceramic reinforced Mo-based composite coating fabricated by Argon shielded Arc cladding
Authors: Kumar Ravi , Das Anil Kumar
Published: June 2023

In this study, Mo-based composite coatings with 1 wt.% of rare Earth oxide (Y2O3) contents were successfully manufactured on AISI SS304 (stainless steel) by argon shielded arc (ASAC) cladding method. The effect of Y2O3 on phase composition, microstructure, mechanical and tribological properties of Mo-based coatings were investigated by x-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM) with energy dispersive x-ray spectrometer (EDS), micro-Vickers hardness apparatus and pin-on-disc type wear tester. The result demonstrates that the upper surface of composite coating with and without addition of Y2O3 were mainly comprised of TiB2, Ni3Ti, Fe3Mo, MoNi4, NiTi, Mo2B, Y2TiO7, Cr2Ti, Fe3B, Y2O3, and MoNi4 appeared. The constituent phase components in the coated layer were found to be beneficial for the enhancement of the microhardness and wear resistance. The maximum value of average micro-hardness and wear resistance was observed in samples having 1 wt.% of Y2O3 as a precursor. The average microhardness of Mo-based coatings with Y2O3 addition was in the range of 1599 to 2170.4 HV0.1 and wear resistance increases from 1.41 to 6.36 × 10−8 g/N-m. The pronounced effect of Y2O3 addition on microhardness and wear resistance of coatings were consistent with the calculation results of applied multivariate statistical analysis. Thus, it can be concluded that the addition of Y2O3 is effective and achievable way to solidate hardness and wear resistance of Mo-based coatings.
How Cr doping influences on the properties of ZnO nanoparticles obtained by aqueous synthesis: Exploring at low Cr concentrations
Authors: Iribarren A , González-Hurtado M , George Ponce de León G , Durán-Sosa I , Castro-Rodríguez R
Published: June 2023

A detailed physico-chemical study of Cr3+-doped ZnO nanoparticles (NPs) obtained via aqueous synthesis was carried out. The NPs acquire greenish tonality as the Cr concentration increased. High efficiency of Cr incorporation into the ZnO lattice was found up to approximately 1 at% Cr. The ZnO:Cr NPs show wurtzite hexagonal phase with a lattice compressed for low Cr concentration and tensed for higher concentrations. Structural, chemical and optical analyses indicate that for low Cr concentration Cr occupies the Zn vacancy sites, owing to the reduction in acceptor compensation by passivating the Zn vacancies and the contribution of the unpaired electron of Cr3+, which induces an increase of electron concentration, changes in the conductivity, transport of carriers, optical properties and ferromagnetic properties, among others. At higher Cr concentrations, the passivation of Zn vacancies by Cr atoms reduces the acceptor contribution, and substantial substitution of Zn atoms by Cr atoms in the ZnO lattice strengthens the retention of O atoms in the Cr-O bonds. This results in a reduction in O vacancy concentration, donor contribution, strain, electron concentration, and luminescence intensity.
Reconstruction algorithm for the runaway electron energy distribution function of the ITER hard x-ray monitor
Authors: Patel Ansh , Pandya Santosh P , Shevelev Alexander E , Khilkevitch E M , Iliasova Margarita , O’Connor Richard , Tieulent Raphael , Barnsley Robin , Mokeev Alexander N
Published: June 2023

Hard x-ray (HXR) spectrometry in ITER can provide information about Runaway Electrons (REs) in tokamak plasmas. Non-trivial reconstruction techniques must be applied to study the Energy distribution of REs in tokamaks since the diagnostic signals are convoluted with the emission of bremsstrahlung radiation from REs reaching the detector and the detector response function. A developed tool, coupled with the PREDICT code, has been described in this report for reconstructing the Runaway Electron energy distribution function (REDF) from HXR spectrum. Bremsstrahlung emission spectra and the detector response function are utilized in a forward modelling process to generate synthetic HXR spectra for different test REDF to which artificial noise is added. These HXR spectra are utilized to reconstruct the REDFs that can provide information about the REs in the plasma. The reconstruction process has been applied to the ITER HXR Monitor configuration for the first time. The effect of reduced optical transmission efficiency is studied on the reconstruction process and the accuracy of the extracted RE parameters. The performance of the reconstruction process is also tested for different amount of photon counts to identify the minimum number of photon counts required for optimal reconstruction. Preliminary results of RE-current estimation using the reconstruction process are also presented.
Structural and optical properties of lithium borate glasses under extreme conditions of ion irradiation
Authors: Karthika S , Asokan K , Marimuthu K , Teresa P Evangelin , Meena Ramcharan , Durairajan A , Valente MA , Meena P , Sankaran Shanmuga Sundari
Published: June 2023

Lithium borate (LBO) glasses of the composition 10LiO2.90B2O3 were prepared by melt quenching technique and characterized for morphological, structural, and optical properties before and after the exposure to the extreme conditions of 100 MeV Ni ion irradiation. Both the morphological images and structural properties confirm the transformation of LBO glasses from amorphous to polycrystalline nature. This Ni irradiation provides thermal energy that causes the ceramization of glass. The beam interacts with the material where the top layer of the glass remelts, and ultrafast re-solidification occurs after the termination of the ion beams. The Rietveld refinement using the x-ray diffraction data shows that the irradiated LBO possesses a monoclinic crystal structure of lithium pentaborate pentahydrate (B5H10LiO13). The FTIR spectra of Ni ion irradiated glasses show the creation of non-bridging oxygens (NBO) by the formation of BO4 units at the expense of BO3 units. The direct band gap and the Urbach energy of the glasses are affected by the nickel ion irradiation and are in the range 2.73 to 2.55 eV and 0.59 to 0.42 eV. The refractive index also reveals a minor change (1.66 to 1.63). The molar electronic polarizability, metallization criteria, and transmission coefficient were estimated. The coexistence of crystalline and amorphous phases leads to a multiscale phase structure that has multilevel relaxation processes. This is a suitable condition for the improvement of the rheological properties of glass and glass ceramics. Future work involves optimization of the coexistence of these two phases during irradiation.
Improving the efficiency of ZnO/WS2/CZTS1 solar cells using CZTS2 as BSF layer by SCAPS-1D numerical simulation
Authors: Dakua Pratap Kumar , Panda Deepak Kumar
Published: June 2023

With a high absorption coefficient and tunable bandgap CZTS (Copper Zinc Tin Sulfide) makes it suitable for photovoltaic applications. Present paper deals with the simulation and modeling of CZTS-based solar cells using tungsten disulfide (WS2) as the buffer layer and CZTS2 as the back surface field (BSF) layer to study the performance of the solar cell. Considering different physical and geometrical parameters such as thickness, acceptor density, interfacial defect density, and metal contact work functions the device calibration has been done. The temperature is varied from 300 K to 400 K to study the impact on device performance. The C-V and 1/C2 plot is presented to calculate the built-in voltage for the device. The series (Rs) and shunt (Rsh) resistance of 1 and 106 ohm.cm2 were kept throughout the simulation. The optimized thickness for the absorber, BSF, buffer, and window layers are 800 nm, 140 nm, 30 nm, and 90 nm respectively. The obtained results are validated using the experimental results available in the literature. Varying the values of different parameters, the optimal efficiency of 26% was reported in this work. Contrary to conventional solar cells, which contain expensive and toxic elements, WS2 may be a good option as a buffer layer in CZTS solar cells.
Plus-shaped dielectric grating for seven-channel transmission
Authors: Zhou Yongchun , Wang Bo
Published: June 2023

A new seven-channel transmission grating with plus-shaped array under normal incidence is proposed and discussed in this paper. Through the simulated annealing (SA) algorithm and rigorous coupled-wave analysis (RCWA), the novel microstructure can split the incident energy into 0-th/±1-st/±2-nd/±3-rd orders evenly. The influence of incident angle, period, incident wavelength, and other parameters on the diffraction efficiency are also analyzed in this paper. For transverse magnetic (TM) polarization, the range of period is 3062–3246 nm and the bandwidth of incident angle and wavelength is 1.96° and 32.3 nm, respectively. It can be concluded that the TM-polarized light of the designed grating has a good performance in incident bandwidth and fabrication tolerance. In addition, the efficiency of transverse electric (TE) polarization has the satisfactory uniformity of 2.40%. Therefore, the proposed grating has a certain significance for the research of multi-port beam splitter, especially for the seven-channel polarization-independent beam splitter.
A path to precision cosmology: synergy between four promising late-universe cosmological probes
Authors: Wu Peng-Ju , Shao Yue , Jin Shang-Jie , Zhang Xin
Published: June 2023

In the next decades, it is necessary to forge new late-universe cosmological probes to precisely measure the Hubble constant and the equation of state of dark energy simultaneously. In this work, we show that the four novel late-universe cosmological probes, 21 cm intensity mapping (IM), fast radio burst (FRB), gravitational wave (GW) standard siren, and strong gravitational lensing (SGL), are expected to be forged into useful tools in solving the Hubble tension and exploring dark energy. We propose that the synergy of them is rather important in cosmology. We simulate the 21 cm IM, FRB, GW, and SGL data based on the hypothetical observations of the Hydrogen Intensity and Real-time Analysis eXperiment, the Square Kilometre Array, the Einstein Telescope, and the Large Synoptic Survey Telescope, respectively. We find that the four probes have different parameter dependencies in cosmological constraints, so any combination of them can break the degeneracies and thus significantly improve the constraint precision. The joint 21 cm IM+FRB+GW+SGL data can provide the constraint errors of σ(Ωm) = 0.0022 and σ(H
0) = 0.16 km s-1 Mpc-1 in the ΛCDM model, which meet the standard of precision cosmology, i.e., the constraint precision of parameters is better than 1%. In addition, the joint data give σ(w) = 0.020 in the wCDM model, and σ(w
0) = 0.066 and σ(wa
) = 0.25 in the w
0
wa
CDM model, which are better than the constraints obtained by the CMB+BAO+SN data. We show that the synergy between the four late-universe cosmological probes has magnificent prospects.
Hypersonic target interception based on short-range damage estimation
Authors: Wang Y Z , Chen K
Published: June 2023

Aiming at the interception problem of hypersonic target end phase, the flight interception simulation based on semi-active radar guidance is firstly established, and a warhead based on fragment damage is designed. Secondly, research proposes an effective method of target damage and verifies the interception effect by simulation. AUTODYN was used to establish the 3D finite element model based on the nonlinear flight dynamics model, to simulate the damage process and fragmentation dispersion. In this paper, the probability of success of missile interception is estimated by using conditional probability and the distribution of fragment field combined with the miss distance in the interception process and the fragment explosive dispersion law of the steel ball, so as to ensure the destruction of the terminal hypersonic incoming weapon within the safe range.
Simulation Environment of Unmanned Group Reconnaissance System Based on RVIZ and GYM
Authors: Weidong Huang , Fulun Peng , Jie Liu , Peng He , Yuan Qi , Bing Yang
Published: June 2023

This paper studies the simulation environment of the current cluster unmanned system, analyzes the shortcomings of the cluster unmanned system, and designs a cluster robot simulation system based on RVIZ and GYM, which has both the fast training algorithm and the physical attributes of the simulation environment, and uses DDS to transmit robot control instructions and state information. After the GYM fast training algorithm, Control the cluster robots to verify the algorithm and collect the state information of the robots in the physical simulation environment of RVIZ. After the whole simulation is passed, the algorithm can be directly used for the path planning of cluster robots. The results show that the simulation environment can effectively simulate the unmanned group reconnaissance system.
Research on Adaptive Flexible Wing with Variable Trailing Edge
Authors: Li Kang , Ba Weitao , Liu Yang , Lv ShuiYan , Yang Yang , Xie LinQing
Published: June 2023

The trailing edge deformable wing is one of the main development directions of future aircraft design. The technology of active camber of wing trailing edge can significantly improve the aerodynamic performance of aircraft. In this paper, the motor drives the parabolic crankshaft and the distributed crankshaft drives the flexible skin of the trailing edge of the wing, which can realize the deflection of the trailing edge of the wing at a large angle of 0~30 degrees. At the same time, the surface of the wing is continuous and smooth. Moreover, the aerodynamic simulation results of the deformed wing show that the trailing edge deflection is beneficial to increase the lift. It can increase the maximum lift coefficient by 2 times and the maximum lift drag ratio by 18%. Adaptive flexible wing technology is applied to rocket sleds with side wings. This technology can increase the downward pressure of the side wing of the rocket block and improve the operation safety.
A fast calculation model for interior ballistics simulation of a recoilless launch system with high chamber pressure
Authors: Xie Wenkui , Sun Yuxin
Published: June 2023

Recoilless launch system is economical and convenient. This paper provided a recoilless launch system with high chamber pressure based on the theory of recoilless gun. A program for interior ballistics simulation of the launch system based on the mixed propellent was designed. The curves of chamber pressure and projectile velocity on time and projectile travels were provided by the program. And the phenomena of different combustion stages presented by the curve are discussed. The simulation results reached the set indicators, and it was consistent with the actual interior ballistics. The designed model has certain reference value for real-time simulation and fast computation.
Study on Damage Effectiveness of Single Projectile of Small Caliber Anti-aircraft Gun Under Multi-error Constraints
Authors: He B , Ren J , Jiang Z J , Fan X , Tang C F , Li X Z , Yang T Q , Feng H Z
Published: June 2023

In this paper, the damage effectiveness of a single projectile of small caliber (30-35 mm) anti-aircraft gun under multi-error constraints is studied. Based on the known prior information of target motion and the dispersion mathematical model of prefabricated fragment warhead, under the constraints of fragment effective killing radius and target equivalent size, the fuze starting characteristic factor is introduced to establish the integrated model of fuze and warhead. Based on the Monte-Carlo method, the variation law of the damage effectiveness of a single projectile under the joint constraints of the gun firing angle error and the fuze fixed range error is analyzed. The simulated annealing (SA) algorithm is used to find the global optimal solution of the model. The optimal damage effectiveness of a single projectile under multi-error constraints is found. The results show that the damage effectiveness of single projectile is increased by 26.91% without changing the state of existing weapon and equipment.
Experimental investigation of ethylene-fueled ramjet rotating detonation engine with an annular combustor
Authors: Feng Wenkang , Zheng Quan , Xiao Qiang , Han Xinpei , Cao Qi , Huang Hanli , Wu Bowen , Weng Chunsheng
Published: June 2023

A ramjet-mode rotating detonation engine fueled by ethylene is designed to demonstrate the feasibility of rotating detonation organization in annular combustor under high-speed incoming flow condition. The incoming flow with the design total temperature of 860 K and Mach number of 2 at the isolator inlet is provided by an air-heater, and the total mass flow is about 1.0 kg/s. The results show that the ramjet rotating detonation engine can operate in detonation mode when the equivalence ratio (ER) is no less than 0.54. By high-frequency pressure analysis and optical observation, two propagation modes of detonation wave are observed: rotating detonation in the ER range of 0.54-0.71 and longitudinally pulsating detonation in the ER range of 0.82-0.97. In rotating detonation mode, the wave velocity increases as ER increases, and the detonation velocities are about 60% of the CJ value. In longitudinally pulsating detonation mode, the propagation frequencies of the detonation wave are in the range of 1010 Hz-1017 Hz, which is much lower than that in rotating detonation mode, and the upstream propagation velocity of the detonation wave is estimated as 964 m/s. In addition, the maximum static pressure in the combustor increases with the ER from 0.54 to 0.97, and reaches 0.24 MPa when ER is 0.97. When ER is no more than 0.58, the isolator can effectively suppress the back pressure in the combustor, while ER is no less than 0.71, the back pressure in the combustor affects the flow at the isolator inlet, which implies that the isolator design needs to be optimized.