bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermally stable photoluminescence centers at 1240 nm in silicon obtained by irradiation of the SiO2/Si system
Authors: Nikolskaya Alena , Korolev Dmitry , Mikhaylov Alexey , Pavlov Dmitrii , Sushkov Artem , Okulich Evgenia , Chizhova Anastasia , Konakov Anton , Yunin Pavel , Okhapkin Andrey , Kraev Stanislav , Yablonskiy Artem , Yurasov Dmitry , Zakharov Vsevolod , Andreev Boris , Tetelbaum David
Published: June 2024

The study of light-emitting defects in silicon created by ion implantation has gained renewed interest with the development of quantum optical devices. Improving techniques for creating and optimizing these defects remains a major focus. This work presents a comprehensive analysis of a photoluminescence line at a wavelength of 1240 nm (1 eV) caused by defects arising from the ion irradiation of the SiO2/Si system and subsequent thermal annealing. It is assumed that this emission is due to the formation of defect complexes WM with trigonal symmetry similar to the well-known W-centers. A distinctive feature of these defects is their thermal resistance up to temperatures of 800 °C and less pronounced temperature quenching compared to the W-line. The difference in the properties of these defect centers and W-centers can be explained by their different defect environments, resulting from the larger spatial separation between vacancies and interstitial atoms diffusing from the irradiated layer. This, in turn, is associated with the difference in the distribution of primary radiation defects during irradiation of the SiO2/Si system and silicon not covered with a SiO2 film. The patterns of changes in the WM line depending on various factors, such as the thickness of the SiO2 film, type of conductivity and impurity concentration in the original silicon, irradiation parameters, and annealing regimes, is studied and explained in detail. These findings demonstrate the benefits of this new approach when compared to previous methods.
Latent-to-sensible heat conversion kinetics during nanoparticle coalescence
Authors: Ojha Abhilash , Tamadate Tomoya , Hogan, Christopher J.
Published: June 2024

Coagulational growth in an aerosol is a multistep process; first particles collide, and then they coalesce with one another. Coalescence kinetics have been investigated in numerous prior studies, largely through atomistic simulations of nanoclusters (102–104 atoms). However, with a few exceptions, they have either assumed the process is completely isothermal or is a constant energy process. During coalescence, there is the formation of new bonds, decreasing potential energy, and correspondingly increasing internal kinetic (thermal) energy. Internal kinetic energy evolution is dependent not only on coalescence kinetics but also on heat transfer to the surrounding gas. Here, we develop and test a model of internal kinetic energy evolution in collisionally formed nanoclusters in the presence of a background gas. We find that internal kinetic energy dynamics hinge upon a power law relationship describing latent-to-sensible heat release as well as a modified thermal accommodation coefficient. The model is tested against atomistic models of 1.5–3.0 nm embedded-atom gold nanocluster sintering in argon and helium environments. The model results are in excellent agreement with the simulation results for all tested conditions. Results show that nanocluster effective temperatures can increase by hundreds of Kelvin due to coalescence, but that the rise and re-equilibration of the internal kinetic energy is strongly dependent on the background gas environment. Interestingly, internal kinetic energy change kinetics are also found to be distinct from surface area change kinetics, suggesting that modeling coalescence heat release solely due to surface area change is inaccurate.
Modeling of periodical shearing flow in a fibrous space with applications in shear-induced brain injury
Authors: Lang Ji , Wang Liyun , Wu Qianhong
Published: June 2024

This paper presents a theoretical model examining the interaction between a fibrous network and viscous fluid flow driven by an oscillating boundary. The aim is to understand how oscillating impacts are transmitted from the skull, through the arachnoid trabeculae network filled with cerebrospinal fluid, as observed in shaken baby syndrome. The model uses an effective medium approach to determine the fluid velocity field while each fiber is treated as a soft string undergoing deformation. Results indicate that the frequency of oscillation, fiber stiffness, and porous structure resistance significantly influence the oscillating shearing flow, as indicated by the Womersley (Wo), Brinkman (α), and Bingham (Bm) numbers. Application of the model to shaken baby syndrome suggests that oscillations in the cerebrospinal fluid and arachnoid trabeculae can significantly surpass those on the skull, leading to intense shear stress penetration to the brain. This model is the first study to integrate the dynamic response of string-like fibrous networks in fluid flows with oscillating boundaries and offers a quantitative framework for predicting the transmission of shearing forces from the skull to the brain matter.
Experimental investigation on key parameters influencing unsteady aerodynamics of a 3:2 rectangular prism in accelerating flow
Authors: Chen Xiu-Yu , Zhu Le-Dong , Tan Zhong-Xu
Published: June 2024

This study investigates the unsteady aerodynamic characteristics of a 3:2 rectangular prism under accelerating flow. Wind tunnel tests were primarily conducted in the steady flow to establish a baseline for assessing the unsteady effects induced by flow acceleration on the aerodynamic forces. Aerodynamic parameters in the time and frequency domains were compared across different accelerating flow cases to analyze the influence of accelerating flow characteristics on the unsteadiness of aerodynamic forces. The results demonstrate that the lift force exhibits more pronounced unsteady characteristics compared to drag and moment. The unsteady behavior is primarily influenced by the wind attack angle, starting wind velocity, and maximum acceleration. For wind attack angles of 0° or 90°, the accelerating flow primarily reduces the amplitude of lift fluctuations. In contrast, for other wind attack angles, the accelerating flow causes a deviation in the time-varying mean of lift from the quasi-steady value, accompanied by an amplification of lift fluctuations. Furthermore, the increase in the starting wind velocity leads to a decrease in the deviation of aerodynamic lifts, indicating that higher starting wind velocities weaken the unsteady aerodynamic characteristics induced by accelerating flow. On the other hand, the increase in flow acceleration enhances the unsteady effect on aerodynamic lift, especially for accelerating flow with higher starting wind velocities. Moreover, the Strouhal number during the accelerating process is lower than that in the steady flow, and the degree of reduction is also influenced by starting wind velocity and maximum acceleration.
Divergence of the energy-losing rate of charged particles in plasmas
Authors: Du Bao , Kang Dongguo , Li Kai , Zhang Wenshuai , Zou Shiyang , Deng Luan , Cai Hongbo , Zhu Shaoping
Published: June 2024

In modeling the charged alpha particle transport in hot-spot plasmas of inertial confinement fusion, the energy-losing rate is a major concern in the Monte Carlo simulations of alpha particle transport of a radiative-hydrodynamic code. However, the traditionally used energy stopping-power only describes the averaged energy-losing rate of the incident charged particles, whereas the variance of the energy exchange with the background particles is generally ignored. In this paper, the variance of charged particle collisions is studied by both analytical derivation and Monte Carlo simulations. An expression of the divergence of the charged particle energy-losing rate is given for the first time, which can be directly used for practical estimations. It indicates that when the areal density of the target particles along the incident particle path length is low, the divergence of the lost energy would be much larger than the average value, and the traditionally used energy stopping-power would be no longer sufficient to describe the charged particle Coulomb collisions. It helps to obtain a more comprehensive understanding about the charged particle transport in plasmas.
Large-bipolaron liquids in cuprate superconductors
Authors: Emin David
Published: June 2024

Uniquely, large-bipolarons’ self-trapped holes occupy superoxygens, each comprising four oxygens circumscribed by four coppers in a CuO2 plane, formed as oxygens relax inward and coppers relax outward. Critically, concomitant oxygen-to-copper electron transfer eliminates copper spins. The d-symmetry of superoxygens’ ground state molecular orbital tracks the superoxygens’ predominant zero-point radial vibrations. These large bipolarons’ distinctive charge transport, absorption, magnetism, local atomic vibrations, condensation into a liquid, and subsequent superconductivity are consistent with cuprate superconductors’ long-established unusual properties.
Investigating H-atom reactions in small PAHs with imperfect aromaticity: A combined experimental and computational study of indene (C9H8) and indane (C9H10)
Authors: Schneiker A. , Góbi S. , Ragupathy G. , Keresztes B. , Bazsó G. , Tarczay G.
Published: June 2024

Polycyclic aromatic hydrocarbons (PAHs) are widely recognized as catalysts for interstellar H2 formation. Extensive exploration into the catalytic potential of various PAHs has encompassed both theoretical investigations and experimental studies. In the present study, we focused on studying the reactivity of an imperfect aromatic molecule, indene (C9H8), and its hydrogenated counterpart, indane (C9H10), as potential catalysts for H2 formation within the interstellar medium. The reactions of these molecules with H atoms at 3.1 K were investigated experimentally using the para-H2 matrix isolation technique. Our experimental results demonstrate that both indene and indane are reactive toward H atoms. Indene can participate in H-atom-abstraction and H-atom-addition reactions, whereas indane primarily undergoes H-atom-abstraction reactions. The H-atom-abstraction reaction of indene results in the formation of the 1-indenyl radical (R1) (C9H7) and H2 molecule. Simultaneously, an H-atom-addition reaction forms the 1,2-dihydro-indene-3-yl radical (R2) (C9H9). Experiments also reveal that the H-atom-abstraction reaction of indane also produces the R2 radical. To the best of our knowledge, this study represents the first reporting of the infrared spectra of R1 and R2 radicals. The experimental results, combined with theoretical findings, suggest that indane and indene may play a role in the catalytic formation of interstellar H2. Furthermore, these results imply a quasi-equilibrium between the investigated molecules and the formed radicals via H-atom-addition and H-atom-abstraction reactions.
Richtmyer–Meshkov instability at high Mach number: Non-Newtonian effects
Authors: Rana U. , Abadie T. , Chapman D. , Joiner N. , Matar O. K.
Published: June 2024

The Richtmyer–Meshkov instability (RMI) occurs when a shock wave passes through an interface between fluids of different densities, a phenomenon prevalent in a variety of scenarios including supersonic combustion, supernovae, and inertial confinement fusion. In the most advanced current numerical modeling of RMI, a multitude of secondary physical phenomena are typically neglected that may crucially change in silico predictions. In this study, we investigate the effects of shear-thinning behavior of a fluid on the RMI at negative Atwood numbers via numerical simulations. A parametric study is carried out over a wide range of Atwood and Mach numbers that probes the flow dynamics following the impact on the interface of the initial shock wave and subsequent, reflected shocks. We demonstrate agreement between our numerical results and analytical predictions, which are valid during the early stages of the flow, and examine the effect of the system parameters on the vorticity distribution near the interface. We also carry out an analysis of the rate of vorticity production and dissipation budget which pinpoints the physical mechanisms leading to instability due to the initial and reflected shocks. Our findings indicate that the shear-thinning effects have a significant impact on instability growth and the development of secondary instabilities, which manifest themselves through the formation of Kelvin–Helmholtz waves. Specifically, we demonstrate that these effects influence vorticity generation and damping, which, in turn, affect the RMI growth. These insights have important implications for a range of applications, including inertial confinement fusion and bubble collapse within non-Newtonian materials.
Stringlet excitation model of the boson peak
Authors: Jiang Cunyuan , Baggioli Matteo , Douglas Jack F.
Published: June 2024

The boson peak (BP), a low-energy excess in the vibrational density of states over the Debye contribution, is often identified as a characteristic of amorphous solid materials. Despite decades of efforts, its microscopic origin still remains a mystery. Recently, it has been proposed, and corroborated with simulations, that the BP might stem from intrinsic localized modes involving one-dimensional (1D) string-like excitations (“stringlets”). We build on a theory originally proposed by Lund that describes the localized modes as 1D vibrating strings, but we specify the stringlet size distribution to be exponential, as observed in simulations. We provide an analytical prediction for the BP frequency ωBP in the temperature regime well below the observed glass transition temperature Tg. The prediction involves no free parameters and accords quantitatively with prior simulation observations in 2D and 3D model glasses based on inverse power law potentials. The comparison of the string model to observations is more uncertain when compared to simulations of an Al–Sm metallic glass material at temperatures well above Tg. Nonetheless, our stringlet model of the BP naturally reproduces the softening of the BP frequency upon heating and offers an analytical explanation for the experimentally observed scaling with the shear modulus in the glass state and changes in this scaling in simulations of glass-forming liquids. Finally, the theoretical analysis highlights the existence of a strong damping for the stringlet modes above Tg, which leads to a large low-frequency contribution to the 3D vibrational density of states, observed in both experiments and simulations.
Needed computations and computational capabilities for stellarators
Authors: Boozer Allen H.
Published: June 2024

Stellarator plasmas are externally controlled to a degree unparalleled by any other fusion concept, magnetic or inertial. This control is largely through the magnetic fields produced by external coils. The development of fusion energy could be expedited by carrying out remarkably straight-forward computations to define strategies for exploiting this external control. In addition to these computations, which have a reliability limited only by competence, certain physics areas that affect the development of stellarator power plants should have a more intense study. The low cost and speed with which computations can be carried out relative to experiments have implications for the development of fusion. Computations should be used to develop a strategy that to the extent possible allows major issues to be circumvented. Required computations for this strategy are the subject of this paper.
High pressure melt line of nickel using a generalized embedded atomic method potential
Authors: Zhao Liming , Hamel Sebastien , Lordi Vincenzo , Samanta Amit
Published: June 2024

As the second most abundant metal in the Earth's core, nickel plays an important role in determining the structure and temperature of the Earth's core. Yet, the melt line of Ni at pressures corresponding to the Earth's core has not been explored in the literature. Many previous experimental and simulation efforts have reported the melting point of Ni at pressures below 100 GPa, but there exist large discrepancies, most of which have persisted due to various experimental and simulation bottlenecks in handling extreme pressure and temperature conditions. We adopted the generalized embedded atom method, which overcomes the limitations of existing interatomic potentials, to probe phase stability and phase boundaries of Ni at pressures between 50 and 500 GPa. The potential was validated by comparing the cold curves, phonon dispersion curves, and enthalpies of fusion with ab initio density functional theory calculations. Our analysis shows that face centered cubic (FCC) is stable, and the hexagonal close packed (HCP) and body centered cubic (BCC) phases are metastable close to the melt line. Melting temperatures at different pressures were obtained from two-phase co-existence simulations and take the following functional form: Tm=1969.23+19.15P−0.012P2. In contrast to iron, differences between the melting points of the stable and metastable phases of Ni are less than 250 K at 300 GPa, and the difference in melting points of the metastable BCC and HCP phases changes sign at 500 GPa, which implies that the phase transition mechanisms during solidification can be very complex.
On-the-fly training of polynomial machine learning potentials in computing lattice thermal conductivity
Authors: Togo Atsushi , Seko Atsuto
Published: June 2024

The application of first-principles calculations for predicting lattice thermal conductivity (LTC) in crystalline materials, in conjunction with the linearized phonon Boltzmann equation, has gained increasing popularity. In this calculation, the determination of force constants through first-principles calculations is critical for accurate LTC predictions. For material exploration, performing first-principles LTC calculations in a high-throughput manner is now expected, although it requires significant computational resources. To reduce computational demands, we integrated polynomial machine learning potentials on-the-fly during the first-principles LTC calculations. This paper presents a systematic approach to first-principles LTC calculations. We designed and optimized an efficient workflow that integrates multiple modular software packages. We applied this approach to calculate LTCs for 103 compounds of wurtzite, zinc blende, and rocksalt types to evaluate the performance of the polynomial machine learning potentials in LTC calculations. We demonstrate a significant reduction in the computational resources required for the LTC predictions.
Discrete element-based multi-cluster hydraulic fracture extension study with temporary plugging and fracturing in horizontal wells
Authors: Xiao Hui , Zhang Han , Wang Chunbing , Wang Hongsen , He Tianxi , Xie Xin
Published: June 2024

In this paper, a two dimensional-discrete element method complex fracture extension model was developed to simulate the fracture extension behavior in reservoirs during multi-cluster perforation fracturing of horizontal wells by particulate flow and considering temporary plugging conditions. The effect of particle inhomogeneity on the extension of multi-cluster fractures, the change of fracture extending characteristics before and after temporary plugging, and the effect of geological and construction parameters on the extension of multi-cluster fractures under the consideration of temporary plugging conditions are investigated in this model. The results show that: (1) the middle cluster is more difficult to extend than the outermost cluster due to interstitial stress interference; the increased nonuniformity of particles aggravates interstitial stress interference and favors shear fracture extension. (2) Fractures expand substantially when the fracturing fluid reaches 3/4 of the total fluid volume; after temporary plugging, it can promote the uniform extension of fractures and increase the total length of fractures, but the fractures formed in the middle are easy to be captured by the fractures at the two ends and expand along it, and it is not easy to form complex fractures; the timing of plugging is based on the percentage of perforation clusters with fractures already formed, with fracture extension being preferred. (3) The horizontal principal stress difference mainly affects the direction of fracture extension; the number of clusters mainly affects the uniformity of fracture extension; and the fluid flow mainly affects the length of fracture extension.
Genetic programing control of self-excited thermoacoustic oscillations
Authors: Yin Bo , Yang Zhijian , Guan Yu , Redonnet Stephane , Gupta Vikrant , Li Larry K. B.
Published: June 2024

In this experimental study, we use a data-driven machine learning framework based on genetic programing (GP) to discover model-free control laws (individuals) for suppressing self-excited thermoacoustic oscillations in a prototypical laminar combustor. This GP framework relies on an evolutionary algorithm to make decisions based on natural selection. Starting from an initial generation of individuals, we rank their performance based on a cost function that accounts for the trade-off between the state cost (thermoacoustic amplitude) and the input cost (actuator power). We then breed subsequent generations of individuals via a tournament in which the direct forwarding of elite individuals occurs alongside genetic operations such as mutation, replication, and crossover. We implement this GP control framework in both closed-loop and open-loop forms, followed by benchmarking against conventional open-loop control based on time-periodic forcing. We find that while all three control strategies can achieve similarly large reductions in thermoacoustic amplitude, GP closed-loop control consumes the least actuator power, making it the most efficient. It achieves this efficiency by learning an actuation mechanism that exploits the strong heat-release-rate amplification of the open flame at its preferred mode, even though the GP algorithm has never seen the open flame itself. This study demonstrates the feasibility of using GP to discover new and more efficient model-free individuals for suppressing self-excited thermoacoustic oscillations, providing a promising approach to data-driven feedback control of combustion devices.
VSCF/VCI theory based on the Podolsky Hamiltonian
Authors: Schneider Moritz , Rauhut Guntram
Published: June 2024

While the vibrational spectra of semi-rigid molecules can be computed on approaches relying on the Watson Hamiltonian, floppy molecules or molecular clusters are better described by Hamiltonians, which are capable of dealing with any curvilinear coordinates. It is the kinetic energy operator (KEO) of these Hamiltonians, which render the correlated calculations relying on them rather costly. Novel implementation of vibrational self-consistent field theory and vibrational configuration interaction theory on the basis of the Podolsky Hamiltonian are reported, in which the inverse of the metric tensor, i.e., the G matrix, is represented by an n-mode expansion expressed in terms of polynomials. An analysis of the importance of the individual terms of the KEO with respect to the truncation orders of the n-mode expansion is provided. Benchmark calculations have been performed for the cis-HOPO and methanimine, H2CNH, molecules and are compared to experimental data and to calculations based on the Watson Hamiltonian and the internal coordinate path Hamiltonian.
Axial acoustic signature of dual detonation tubes
Authors: Li Cheng , Li Ning , Huang Xiao-long , Lv Hai-cheng , Weng Chun-sheng
Published: June 2024

The axial acoustic characteristics of detonation sound waves generated by single and dual detonation tubes, utilizing methane as fuel and oxygen as oxidizers, are experimentally investigated. Various acoustic parameters are analyzed, including the effective sound pressure level, A duration, and energy characteristics. By the A duration, we mean the time when the sound pressure ascends to a significant maximum and then swiftly descends to the ambient pressure. Experimental results reveal that the decay rate of the effective sound pressure level gradually decreases with increasing distance, with ground reflection prolonging the A duration. The energy of the detonation sound wave is primarily concentrated in the low frequency, and the proportion of low-frequency energy increases with distance. For the dual detonation tubes, the detonation sound wave exhibits a higher effective sound pressure level and A duration compared to the single detonation tube. Although the energy proportion and wave structures of detonation sound waves generated by the dual detonation tubes are similar to those of the single detonation tube, the high-frequency energy experiences greater gain. The effective sound pressure level of the dual detonation tubes increases with the separation distance. Altering the ignition interval can transfer energy to lower frequencies, albeit slightly reducing the effective sound pressure level. These findings highlight the significant impact of the spacing between dual detonation tubes on the effective sound pressure level, and the potential for changing the ignition interval to modify the energy characteristics of the detonation sound wave.
Accelerated biological aging six decades after prenatal famine exposure
Authors: Cheng Mengling , Conley Dalton , Kuipers Tom , Li Chihua , Ryan Calen P. , Taeubert M. Jazmin , Wang Shuang , Wang Tian , Zhou Jiayi , Schmitz Lauren L. , Tobi Elmar W. , Heijmans Bastiaan T. , Lumey L. H. , Belsky Daniel W.
Published: June 2024

To test the hypothesis that early-life adversity accelerates the pace of biological aging, we analyzed data from the Dutch Hunger Winter Families Study (DHWFS, N = 951). DHWFS is a natural-experiment birth-cohort study of survivors of in-utero exposure to famine conditions caused by the German occupation of the Western Netherlands in Winter 1944 to 1945, matched controls, and their siblings. We conducted DNA methylation analysis of blood samples collected when the survivors were aged 58 to quantify biological aging using the DunedinPACE, GrimAge, and PhenoAge epigenetic clocks. Famine survivors had faster DunedinPACE, as compared with controls. This effect was strongest among women. Results were similar for GrimAge, although effect-sizes were smaller. We observed no differences in PhenoAge between survivors and controls. Famine effects were not accounted for by blood-cell composition and were similar for individuals exposed early and later in gestation. Findings suggest in-utero undernutrition may accelerate biological aging in later life.
The red alga
Porphyridium
as a host for molecular farming: Efficient production of immunologically active hepatitis C virus glycoprotein
Authors: Hammel Alexander , Cucos Lia-Maria , Caras Iuliana , Ionescu Irina , Tucureanu Catalin , Tofan Vlad , Costache Adriana , Onu Adrian , Hoepfner Lara , Hippler Michael , Neupert Juliane , Popescu Costin-Ioan , Stavaru Crina , Branza-Nichita Norica , Bock Ralph
Published: June 2024

Microalgae are promising production platforms for the cost-effective production of recombinant proteins. We have recently established that the red alga
Porphyridium purpureum
provides superior transgene expression properties, due to the episomal maintenance of transformation vectors as multicopy plasmids in the nucleus. Here, we have explored the potential of
Porphyridium
to synthesize complex pharmaceutical proteins to high levels. Testing expression constructs for a candidate subunit vaccine against the hepatitis C virus (HCV), we show that the soluble HCV E2 glycoprotein can be produced in transgenic algal cultures to high levels. The antigen undergoes faithful posttranslational modification by N-glycosylation and is recognized by conformationally selective antibodies, suggesting that it adopts a proper antigenic conformation in the endoplasmic reticulum of red algal cells. We also report the experimental determination of the structure of the N-glycan moiety that is attached to glycosylated proteins in
Porphyridium
. Finally, we demonstrate the immunogenicity of the HCV antigen produced in red algae when administered by injection as pure protein or by feeding of algal biomass.
Nitrogen and sulfur for phosphorus: Lipidome adaptation of anaerobic sulfate-reducing bacteria in phosphorus-deprived conditions
Authors: Ding Su , Grossi Vincent , Hopmans Ellen C. , Bale Nicole J. , Cravo-Laureau Cristiana , Sinninghe Damsté Jaap S.
Published: June 2024

Understanding how microbial lipidomes adapt to environmental and nutrient stress is crucial for comprehending microbial survival and functionality. Certain anaerobic bacteria can synthesize glycerolipids with ether/ester bonds, yet the complexities of their lipidome remodeling under varying physicochemical and nutritional conditions remain largely unexplored. In this study, we thoroughly examined the lipidome adaptations of
Desulfatibacillum alkenivorans
strain PF2803
T
, a mesophilic anaerobic sulfate-reducing bacterium known for its high proportions of alkylglycerol ether lipids in its membrane, under various cultivation conditions including temperature, pH, salinity, and ammonium and phosphorous concentrations. Employing an extensive analytical and computational lipidomic methodology, we identified an assemblage of nearly 400 distinct lipids, including a range of glycerol ether/ester lipids with various polar head groups. Information theory-based analysis revealed that temperature fluctuations and phosphate scarcity profoundly influenced the lipidome’s composition, leading to an enhanced diversity and specificity of novel lipids. Notably, phosphorous limitation led to the biosynthesis of novel glucuronosylglycerols and sulfur-containing aminolipids, termed butyramide cysteine glycerols, featuring various ether/ester bonds. This suggests a novel adaptive strategy for anaerobic heterotrophs to thrive under phosphorus-depleted conditions, characterized by a diverse array of nitrogen- and sulfur-containing polar head groups, moving beyond a reliance on conventional nonphospholipid types.
Ion velocity effect governs damage annealing process in defective KTaO3
Authors: Velişa G , Iancu D , Zarkadoula E , Tong Y , Zhang Y , Weber W J
Published: June 2024

Effects of electronic to nuclear energy losses (S
e/S
n) ratio on damage evolution in defective KTaO3 have been investigated by irradiating pre-damaged single crystal KTaO3 with intermediate energy O ions (6 MeV, 8 MeV and 12 MeV) at 300 K. By exploring these processes in pre-damaged KTaO3 containing a fractional disorder level of 0.35, the results demonstrate the occurrence of a precursory stage of damage production before the onset of damage annealing process in defective KTaO3 that decreases with O ion energy. The observed ionization-induced annealing process by ion channeling analysis has been further mirrored by high resolution transmission electron microscopy analysis. In addition, the reduction of disorder level is accompanied by the broadening of the disorder profiles to greater depth with increasing ion fluence, and enhanced migration is observed with decreasing O ion energy. Since S
e (∼3.0 keV nm−1) is nearly constant for all 3 ion energies across the pre-damaged depth, the difference in behavior is due to the so-called ‘velocity effect’: the lower ion velocity below the Bragg peak yields a confined spread of the electron cascade and hence an increased energy deposition density. The inelastic thermal spike calculation has further confirmed the existence of a velocity effect, not previously reported in KTaO3 or very scarcely reported in other materials for which the existence of ionization-induced annealing has been reported. In other words, understanding of ionization-induced annealing has been advanced by pointing out that ion velocity effect governs the healing of pre-existing defects, which may have significant implication for the creation of new functionalities in KTaO3 through atomic-level control of microstructural modifications, but may not be limited to KTaO3.
Magneto-transport and thermoelectric studies of antiperovskite semimetal: Mn3SnC
Authors: Gangwar Sunil , Bagga Sonika , Yadav C S
Published: June 2024

We explore the magnetotransport and thermoelectric (Seebeck and Nernst coefficients) properties of Mn3SnC, an antiperovskite magnetic Nodal line semimetal. Mn3SnC shows paramagnetic (PM) to concurrent antiferromagnetic (AFM)/ferromagnetic (FM) transition at T ∼ 286 K. The electrical resistivity and Seebeck coefficient indicate the importance of electron–magnon scattering in the concurrent AFM/FM regime. We observed a large positive magnetoresistance (MR) of ∼8.2 at 8 T field near magnetic transition, in the otherwise negative MR behaviour for low temperatures. The electrical resistivity and MR show a weak thermal hysteresis around the boundary of transition temperature and the width of hysteresis decreases as magnetic field increases. Interestingly the Hall and Seebeck coefficients change sign from positive to negative below the transition temperature, highlighting the different scattering for holes and electrons in this multi-band system. The Seebeck and Nernst signal exhibit two sharp anomalies; one at the transition temperature and another at ∼50 K. The anomaly at magnetic transition in the Nernst signal disappear at 8 T magnetic field, owing to the reduction of magnetic fluctuation. A pseudo-gap near the Fermi level produces an upturn with a broad minimum in the Seebeck signal.
Object and person tracking systems to enable extremity dosimetry in nuclear medicine using computational methods
Authors: Rondón Daniel Santiago , Lombardo Pasquale , Abdelrahman Mahmoud , Struelens Lara , Vanhavere Filip , Bergans Niki
Published: June 2024

Nuclear medicine (NM) professionals are potentially exposed to high doses of ionising radiation, particularly in the skin of the hands. Ring dosimeters are used by the workers to ensure extremity doses are kept below the legal limits. However, ring dosimeters are often susceptible to large uncertainties, so it is difficult to ensure a correct measurement using the traditional occupational monitoring methods. An alternative solution is to calculate the absorbed dose by using Monte Carlo simulations. This method could reduce the uncertainty in dose calculation if the exact positions of the worker and the radiation source are represented in these simulations. In this study we present a set of computer vision and artificial intelligence algorithms that allow us to track the exact position of unshielded syringes and the hands of NM workers. We showcase a possible hardware configuration to acquire the necessary input data for the algorithms. And finally, we assess the tracking confidence of our software. The tracking accuracy achieved for the syringe detection was 57% and for the hand detection 98%.
The difficulty of nuclear emergency prevention measures during natural disasters: ongoing challenges in Japan
Authors: Yamamura Momoka , Saito Yoshika , Nonaka Saori , Sawano Toyoaki , Matsumoto Chihiro , Ozaki Akihiko , Yamamoto Chika , Zhao Tianchen , Saito Hiroaki , Kosaka Makoto , Abe Toshiki , Tsubokura Masaharu
Published: June 2024

It is crucial to anticipate nuclear emergency scenarios and implement effective measures. Japan’s climate and topography make it vulnerable to natural disasters; thus, it is necessary to address compounding and cascading disaster scenarios involving the simultaneous occurrence of natural and nuclear disasters. On 1 January 2024, an earthquake hit the Noto region of Ishikawa Prefecture, resulting in damage to the area around the Shika Nuclear Power Plant, located 90 km from the epicenter. This earthquake revealed that, in the event of a complex disaster, it is possible that residents living within 30 km of the Shika Nuclear Power Plant will be completely unprepared for a nuclear disaster. In the event of a complex disaster, it is crucial to implement appropriate countermeasures while balancing responses to both nuclear and natural disasters and optimizing radiation disaster prevention measures.
Atomistic study of intermetallics of Fe–Al–Zn system and their interfacial properties
Authors: Chen Kefan , Mun Sungkwang , Baskes Michael , Horstemeyer Mark , Li Bin
Published: June 2024

Galvanizing is an important industrial process to improve the corrosion resistance of advanced high strength steels (AHSSs) that are vital for automotive industries. During galvanizing, nanoscale intermetallic phases with complex crystal structures are formed at the interface between the steel substrate and the zinc overlay. To better understand the nanoscale structures and the interfacial properties between the intermetallics, in this work, we develop a second nearest neighbor (2NN) Fe–Al–Zn ternary Modified Embedded Atom Method (MEAM) potential to describe the crystal structures of the intermetallics, i.e. Fe3Al8, Fe4Zn9 and FeZn13 and to calculate the interfacial structure and energy between them. The developed MEAM potential describes well the complex crystal structures and can be used to investigate the interfacial properties that are difficult to obtain from experiments. The Fe4Zn9, FeZn13 surface energies; the Fe–Fe4Zn9, Fe–FeZn13, Fe3Al8–FeZn13 interfacial energies; and the work of adhesion are calculated with the developed MEAM potential. The results show that FeZn13 crystal orientation has an insignificant effect on the FeZn13 surface energy and the Fe–FeZn13 interfacial energy. A negative interfacial energy is obtained for the Fe–Fe4Zn9 and the Fe–FeZn13 interface. The lowest interfacial energy is obtained in the {100}Fe case. The interfacial energy of Fe3Al8–FeZn13 depends on the surface termination of Fe3Al8 and FeZn13. A low interfacial energy is obtained when the surface termination of Fe3Al8 and FeZn13 are both Fe rich. In contrast, when the surface termination of Fe3Al8 is Al rich or the surface termination of FeZn13 is Zn rich, no low energy, stable interface can be formed between the two phases.
Two-stage feature selection for machine learning-aided DFT-based surface reactivity study on single-atom alloys
Authors: Ordillo Viejay Z , Shimizu Koji , Putungan Darwin B , Santos-Putungan Alexandra B , Watanabe Satoshi , de Leon Rizalinda L , Ocon Joey D , Pilario Karl Ezra S , Padama Allan Abraham B
Published: June 2024

This paper presents a feature-centric strategy for predicting adsorption energies of key CO2 reduction reaction (CO2RR) adsorbates, CO and H species, utilizing density functional theory-based calculations for eight adsorption sites and considering alloying effects of nine transition metals at single-atom concentrations. Here, we explore a class of materials consisting of a majority host metal where individual atoms of a different element are dispersed called single-atom alloys (SAA). A total of eight feature selection methods are assessed within Gradient Boosting Regression and Linear Regression models. This study proposes a practical and effective two-stage approach that narrows down the initial 86 features to subsets of 10 and 7 for CO and H adsorption energy predictions, respectively, with the arithmetic mean of valence electrons (VE-am) feature consistently emerging as highly influential, validated through permutation and Shapley additive explanations-based feature importance analyses. The models exhibit robust performance on unseen data, indicating their generalization capability. The findings emphasize VE-am as a potential key machine learning feature for CO2RR on SAA surfaces and underline the effectiveness of the feature-centric approach in understanding feature impacts in machine learning models for CO2RR on SAA systems. Additionally, while other features based on structural, electronic and elemental properties may not individually impact the model significantly, their collective contribution plays a vital role in achieving more accurate adsorption energy predictions.
Site-selective core/shell deposition of tin on multi-segment nanowires for magnetic assembly and soldered interconnection
Authors: Fratto Edward , Wang Jirui , Yang Zhengyang , Sun Hongwei , Gu Zhiyong
Published: June 2024

The field of nanotechnology continues to grow with the ongoing discovery and characterization of novel nanomaterials with unconventional size-dependent properties; however, the ability to apply modern manufacturing strategies for practical device design of these nanoscale structures is significantly limited by their small size. Although interconnection has been previously demonstrated between nanoscale components, such approaches often require the use of expensive oxidation-resistant noble metal materials and time-consuming or untargeted strategies for welded interconnection such as laser ablation or plasmonic resonance across randomly oriented component networks. In this work, a three-segment gold–nickel–gold nanowire structure is synthesized using templated electrodeposition and modified via monolayer-directed aqueous chemical reduction of tin solder selectively on the gold segments. This core/shell nanowire structure is capable of directed magnetic assembly tip-to-tip and along substrate pads in network orientation. Upon infrared heating in a flux vapor atmosphere, the solder payload melts and establishes robust and highly conductive wire–wire joints. The targeted solder deposition strategy has been applied to various other multi-segment gold/nickel nanowire configurations and other metallic systems to demonstrate the capability of the approach. This core/shell technique of pre-loading magnetically active nanowires with solder material simplifies the associated challenges of size-dependent component orientation in the manufacture of nanoscale electronic devices.
Enhancing lyceum physics education with LAB Disc technology: a comparative study
Authors: Sharifov Galib
Published: June 2024

The present study explores the impact of LAB Disc technology on enhancing physics education among gifted ninth-grade students in lyceums. The study employed a quasi-experimental design to examine students’ academic performance and engagement levels in two groups: an experimental group that utilised LAB Discs and a control group that received conventional physics education. To ensure comparability in baseline understanding of the subject, each group consisted of 30 ninth-grade students who were selected based on their academic prowess and enthusiasm for physics. The utilisation of LAB Discs, versatile devices equipped with diverse sensors for instantaneous data gathering and examination, was designed to offer a more engaging and experiential learning encounter. The study’s methodology employed a combination of quantitative and qualitative data collection techniques, including tests, surveys, interviews, and classroom observations. The impact of LAB Disc technology on students’ learning outcomes was assessed using an independent t-test and boxplot visualisation. The results demonstrated a statistically significant enhancement in ninth-grade students’ comprehension and involvement when utilising LAB Disc technology, as evidenced by a t-statistic of 6.522 and a p-value of less than 0.001. The boxplot analysis validated that students in the experimental group exhibited a superior median score and demonstrated greater consistency in their performance. The results emphasise the capacity of interactive educational tools, like LAB Discs, to enhance cognitive abilities and establish a more captivating learning atmosphere in physics classes at the lyceum level.
Determining the refractive index of transparent materials using total internal reflection in teaching experiment
Authors: Luo Duan-bin
Published: June 2024

In this paper, we introduce a three-dimensional demonstration for the refraction and reflection based on total internal reflection of light in transparent media, and discuss the reasons for the formation of circular bright areas and circular shadows, respectively. Then, according to the relationship between the diameter of circular shadows and bright areas, the depth of water, and the thickness of the polymethyl methacrylate plate, we described a teaching experiment based on total internal reflection of light to achieve refractive index measurement of transparent liquids and solids. The refractive index of transparent media measured using this method is in good agreement with reported data.
Experimental study on the discharge characteristics of an air rotating gliding arc
Authors: Sun Su-Rong , Chen Fei , Zheng Yu-Hang , Wang Chao , Wang Hai-Xing
Published: June 2024

In this study, the discharge characteristics of an air rotating gliding arc (RGA) are investigated by synchronous measurements of a digital oscilloscope and a high-speed camera, and the emission spectrum measurement. The discharge evolution in one complete motion cycle exhibits a ‘breakdown-elongation-extinction’ process accompanied by a jump phenomenon of the arc root and a back-breakdown phenomenon. The discharge evolves from the unstable breakdown mode (U-B), to the transition mode and finally to the stable gliding mode (S-G) by increasing the input voltage or decreasing the tangential and axial gas flow rates. The U-B mode at an input voltage of 120 V is featured by the large reduced electric field and high electron temperature of 1.90 eV, but the arc length and existence time are very short. The S-G mode at an input voltage of 270 V has a relatively low breakdown frequency of 0.33 kHz and an average breakdown current of 1.31 A, implying that the arc steadily glides and rotates along the spiral electrode. The average electron temperature is 0.64 eV in the S-G mode, while the arc length and existence time are longer. The rotational and vibrational temperatures of the

N

2

(

C

3

∏
u

)

state are respectively measured at 2200 K and 4400 K in the U-B mode, and in the S-G mode are 2600 K and 4820 K. From the evolution of emission intensities of measured excited species, it is found that the

NO
γ

band emission intensity generally rises from the U-B mode to the S-G mode since the gas temperature and arc existence time rise, indicating that the S-G mode may be beneficial for the vibrationally promoted Zeldovich reactions. This study could deepen the understanding of arc characteristics in air RGA for selecting a suitable mode to achieve better plasma performance in practical applications.
High-accuracy data readout in multi-dimensional optical data storage using convolutional neural networks
Authors: Zhu Y P , Xie X Y , Gao J C , Yan Z , Cao Q , Zhang J Y
Published: June 2024

The escalating global volume of digital data poses a critical challenge for storage solutions. Optical data storage techniques have garnered lots of interests due to their excellent offline storage capabilities, including low energy consumption, high capacity, and long lifespan. However, despite the focus on data recording, minimal attention has been dedicated to the readout aspect. This study introduced femtosecond laser direct writing to perform multi-dimensional optical data storage and employed a specialized convolutional neural network to enhance voxel readout accuracy. The proposed network architecture achieved a remarkable voxel readout accuracy of 98.83%, surpassing support vector machine method (90.07%) and LeNet (96.85%). Furthermore, the proposed method yielded a substantial increase in actual user capacity, outperforming traditional approaches and presenting a novel solution for addressing readout challenges in multi-dimensional optical data storage.