bluuebunny/crossref_metadata_2025_split huggingface dataset:
Instantaneous Marcus theory for photoinduced charge transfer dynamics in multistate harmonic model systems
Authors: Liu Zengkui , Sun Xiang 
Published: April 2024

Abstract
Modeling the dynamics of photoinduced charge transfer (CT) in condensed phases presents challenges due to complicated many-body interactions and the quantum nature of electronic transitions. While traditional Marcus theory is a robust method for calculating CT rate constants between electronic states, it cannot account for the nonequilibrium effects arising from the initial nuclear state preparation. In this study, we employ the instantaneous Marcus theory (IMT) to simulate photoinduced CT dynamics. IMT incorporates nonequilibrium structural relaxation following a vertical photoexcitation from the equilibrated ground state, yielding a time-dependent rate coefficient. The multistate harmonic (MSH) model Hamiltonian characterizes an organic photovoltaic carotenoid-porphyrin-fullerene triad dissolved in explicit tetrahydrofuran solvent, constructed by mapping all-atom inputs from molecular dynamics simulations. Our calculations reveal that the electronic population dynamics of the MSH models obtained with IMT agree with the more accurate quantum-mechanical nonequilibrium Fermi’s golden rule. This alignment suggests that IMT provides a practical approach to understanding nonadiabatic CT dynamics in condensed-phase systems.
MDs-NP: a property prediction model construction procedure for naphtha based on molecular dynamics simulation
Authors: Wei Yixin , Qiu Tong 
Published: April 2024

Abstract
In the context of carbon neutrality and carbon peaking, molecular management has become a focus of the petrochemical industry. The key to achieving molecular management is molecular reconstruction, which relies on rapid and accurate calculation of oil properties. Focusing on naphtha, we proposed a novel property prediction model construction procedure (MDs-NP) employing molecular dynamics simulations for property collections and gamma distribution from real analytical data for calculating mole fractions of simulation mixtures. We calculated 348 sets of mixture properties data in the range of 273 K–300 K by molecular dynamics simulations. Molecular feature extraction was based on molecular descriptors. In addition to descriptors based on open-source toolkits (RDKit and Mordred), we designed 12 naphtha knowledge (NK) descriptors with a focus on naphtha. Three machine learning algorithms (support vector regression, extreme gradient boosting and artificial neural network) were applied and compared to establish models for the prediction of the density and viscosity of naphtha. Mordred and NK descriptors + support vector regression algorithm achieved the best performance for density. The selected RDKFp and NK descriptors + artificial neural network algorithm achieved the best performance for viscosity. Using ablation studies, T, P_w and CC(C)C are three effective descriptors in NK that can improve the performance of the property prediction models. MDs-NP has the potential to be extended to more properties as well as more-complex petroleum systems. The models from MDs-NP can be used for rapid molecular reconstruction to facilitate construction of data-driven models and intelligent transformation of petrochemical processes.
Radiological complexity of nuclear facilities: an information complexity approach to workplace monitoring
Authors: Chakraborty Abinash , Parashar Neeraj , Kumar Pandey Dhananjay , Kumar Pankaj , Deokar U V , Pandey J P N , Kulkarni M S 
Published: April 2024

Abstract
Nuclear energy is crucial for achieving net-zero carbon emissions. A big challenge in the nuclear sector is ensuring the safety of radiation workers and the environment, while being cost-effective. Workplace monitoring is key to protecting workers from risks of ionising radiation. Traditional monitoring involves radiological surveillance via installed radiation monitors, continuously recording measurements like radiation fields and airborne particulate radioactivity concentrations, especially where sudden radiation changes could significantly impact workers. However, this approach struggles to detect incremental changes over a long period of time in the radiological measurements of the facility. To address this limitation, we propose abstracting a nuclear facility as a complex system. We then quantify the information complexity of the facility’s radiological measurements using an entropic metric. Our findings indicate that the inferences and interpretations from our abstraction have a firm basis for interpretation and can enhance current workplace monitoring systems. We suggest the implementation of a radiological complexity-based alarm system to complement existing radiation level-based systems. The abstraction synthesized here is independent of the type of nuclear facility, and hence is a general approach to workplace monitoring at a nuclear facility.
Application of 2E-2U method for free-field underwater calibrations of hydrophones and projectors in a reverberant laboratory test tank
Authors: Çorakçı Ata Can , Biber Alper , Saydam Talha , Aksoy Serkan 
Published: April 2024

Abstract
In this paper, application of a Two-Equations Two-Unknowns (2E-2U) method is described for calibration of hydrophones and projectors below 1 kHz in a laboratory test tank. At low frequencies, amplitude and phase measurements for the calibration of the hydrophones and projectors in the test tank are difficult to perform since echo-free time of the laboratory test tank is not large enough due to transducer initial transients and tank wall boundary reflections. To overcome these difficulties, the 2E-2U method is applied to received (windowed) signals obtained during calibration measurements. Thus, calibration measurements become possible at a frequency down to 250 Hz. These measurements in the test tank are performed for a hydrophone and a developed flextensional projector. First, the received sensitivities for the hydrophone are calculated and validated by comparisons with pressure calibration in a closed chamber. Good agreements are obtained between the two measurement platforms, with a maximum difference of 0.5 dB and uncertainty of 1.3 dB. Then, the transmitting voltage response (TVR) of the flextensional projector is calculated and compared with the calibration data obtained from the method defined in the relevant standards. Good agreements are obtained between the two TVR data with a maximum difference of 1.1 dB and uncertainty of 1.7 dB.
First-principles study of the effect of strain on the structural and optoelectronic properties of flexible photovoltaic material Cs2AgInBr6
Authors: Bareth Brij Kumar , Tripathi Madhvendra Nath 
Published: April 2024

Abstract
The lead-free double-perovskite halide materials are promising materials for photovoltaics. Recently, Cs2AgInBr6 (CAIB) has been synthesized with the estimated direct nature of a band gap value of 1.57 eV. To cover the wide solar spectrum for photo-conversion, the applied strain is one of the promising approaches to achieve it through band gap tuning. The density functional theory is used to investigate the effect of compressive strain on the structural, electronic, and optical properties of CAIB. The elastic constants follow the Born–Huang stability criterion and show the mechanical stability of the composition even under compressive strain. The Poisson’s ratio in the range of 0.23–0.26 and B/G > 1.75 indicate the ductile and soft nature of the material. The band gap increases monotonically without changing the direct nature of the band gap by increasing the compressive strain. However, the larger value of strain reproduces more dispersive conduction band minima and valence band maxima, resulting in lower effective masses and consequently larger carrier mobilities. The variations in the optical properties of CAIB are explored under compressive strain. The structural, electronic, and good photo response of the material in the visible and ultraviolet regions indicate the suitability of the material for flexible photovoltaics.
Gyro-kinetic simulations of trapped electron collision effects on low-frequency drift-wave instabilities in tokamak plasmas
Authors: Tao Y Q , Wang L , Xu G S , Chen R , Yan N , Sun P J , Yang Q Q , Lin X , Ye Y 
Published: April 2024

Abstract
Low-frequency drift-wave instabilities play a crucial role in the radial transport of present-day tokamaks, and trapped electron collisions can significantly influence these instabilities. In this paper, the effects of trapped electron collisions on these instabilities are investigated based on linear gyro-kinetic simulations. The basic numerical techniques including dispersion relation integral method and orthogonal basis function expansion are presented in detail with necessary benchmark work. The results demonstrate that in medium gradients, the increase of trapped electron proportions promotes the growth rate and radial heat transport largely for quasi-linear trapped electron modes (TEMs) and ion temperature gradient (ITG) modes. Moreover, trapped electron collisions have strong stabilizing effects, especially for TEMs driven by electron temperature gradients. Two distinctive branches, namely Mode #1 and #2, are investigated in steep gradients. Both behave in a varied instability nature during different ranges of the normalized wave vector

k
^

θ

. Mode #1 mainly induces radial heat transport during

k
^

θ

<
0.5

and is significantly suppressed by the collisions. Mode #2 mainly induces radial heat transport during

0.4
<

k
^

θ

<
0.8

, and is largely enhanced by the collisions. When the collisionality is large enough, Mode #2 has stronger transport capacity than the other. Mode #2 at the medium wave vector, known as dissipative TEM, may provide the mechanism of the edge coherent mode observed in EAST H-mode plasmas, wherein collisionality plays an important role in the mode excitation.
Optimal collimation of proton beams accelerated by a Laguerre–Gaussian laser with a proper pulse duration
Authors: Wang Mengjiao , Wang Wenpeng , Shi Zhiyong , Ma Huiting , Sun Fengyu , Sun Xinyue , Lv Zhengxing , Leng Yuxin , Li Ruxin 
Published: April 2024

Abstract
In this study, three-dimensional particle-in-cell (PIC) simulations were conducted to evaluate a collimated proton beam accelerated by an intense Laguerre–Gaussian (LG) laser with different pulse durations. The flux and energy of the collimated proton beam could be simultaneously enhanced by selecting an optimal pulse duration. This phenomenon can be primarily attributed to the correlation between the LG laser driven self-generated magnetic field and pulse duration, and this correlation enables the collimation of protons during their interaction and transport. The results obtained in this study elucidate the formation mechanism of different collimated proton patterns, driven by femtosecond and picosecond LG lasers, observed in previous experiments. In addition, based on these results, an optimum pulse duration for high-quality proton beams is proposed for various future applications.
Combined ns pulsed-RF excitation and impedance matching considerations for the production of moderate E/n atmospheric pressure discharges for gas conversion
Authors: Filice Dante , Coulombe Sylvain 
Published: April 2024

Abstract
Sub-breakdown radiofrequency (RF) discharges enabled by a nanosecond (ns) pulse ignition source are studied at atmospheric pressure in a range of gas mixtures from completely inert (in Ar) to completely reactive (in CO2). An electrical characterisation of the continuous wave (CW) RF discharge (13.56 MHz) is performed to determine plasma impedance and plasma power dissipation. Two different measurement methods to electrically characterize the system are described and compared. One method uses in-situ measurements of discharge parameters (voltage, current and the phase angle), and the other method performs ex-situ measurements of the load circuit using a vector network analyser. It was found that RF plasma power deposition depended on the applied RF power as well as the gas mixture composition. Using the in-situ voltage, current and phase angle measurements, plasma power deposition was calculated to be as much as 85% and 76% of the applied RF power for the pure Ar and pure CO2 cases, respectively. A preliminary qualitative assessment of the plasma composition was performed by optical emission spectroscopy, and CO2 conversion by mass spectrometry. CO2 to CO conversions of 11.2% and 5.5% in a 20:80 (CO2:Ar) mixture and in 100% CO2, respectively, were observed. This study demonstrates a RF plasma source for gas conversion applications at atmospheric pressure in a completely reactive gas.
Calculation and prediction of divertor detachment via impurity seeding by using one-dimensional model
Authors: Zhou 周 Wen-Jie 文杰 , Liu 刘 Xiao-Ju 晓菊 , Wu 邬 Xiao-He 潇河 , Li 李 Bang 邦 , Shi 石 Qi-Qi 奇奇 , Fan 樊 Hao-Chen 皓尘 , Yang 杨 Yan-Jie 艳杰 , Li 李 Guo-Qiang 国强 
Published: April 2024

Abstract
Achieving the detachment of divertor can help to alleviate excessive heat load and sputtering problems on the target plates, thereby extending the lifetime of divertor components for fusion devices. In order to provide a fast but relatively reliable prediction of plasma parameters along the flux tube for future device design, a one-dimensional (1D) modeling code for the operating point of impurity seeded detached divertor is developed based on Python language, which is a fluid model based on previous work (Plasma Phys. Control. Fusion
58 045013 (2016)). The experimental observation of the onset of divertor detachment by neon (Ne) and argon (Ar) seeding in EAST is well reproduced by using the 1D modeling code. The comparison between the 1D modeling and two-dimensional (2D) simulation by the SOLPS-ITER code for CFETR detachment operation with Ne and Ar seeding also shows that they are in good agreement. We also predict the radiative power loss and corresponding impurity concentration requirement for achieving divertor detachment via different impurity seeding under high heating power conditions in EAST and CFETR phase II by using the 1D model. Based on the predictions, the optimized parameter space for divertor detachment operation on EAST and CFETR is also determined. Such a simple but reliable 1D model can provide a reasonable parameter input for a detailed and accurate analysis by 2D or three-dimensional (3D) modeling tools through rapid parameter scanning.
Amplification factors for extreme sea level frequency have problematic features as a metric of coastal hazard
Authors: Hall Timothy M 
Published: April 2024

Abstract
The future projected frequency of a specified baseline extreme sea level (ESL), often called the amplification factor (AF), is extensively used as a metric of evolving coastal flood hazard with sea level rise (SLR). The baseline ESL is typically analyzed using extreme value analysis, and the SLR is added to the resulting distribution. In the presence of SLR uncertainty, it is natural to analyze AFs probabilistically. I derive probability density functions (PDFs) of AF, given uncertainty distributions of SLR. If the ESL distribution is modeled as Gumbel and the SLR distribution as normal, then the AF distribution is log normal. However, in active tropical cyclone regions, ESL often has a longer tail than Gumbel, and a Frechet (Type-II) Generalized Extreme Value (GEV) is more appropriate. In this case, I show that the AF distribution has a divergent mean, preventing its use as a hazard metric. In addition, I show that for Frechet ESL, the AF cannot even be defined for SLR above a threshold

β
/
ξ

f

0

−
ξ

,

where f
0 is the specified baseline frequency (e.g., f
0 = 0.01 yr−1 for the 100-year exceedance), β is the GEV scale parameter and ξ the shape parameter. This SLR threshold can be as low as 0.5 m in the southeast US and Caribbean, within reach mid to late century. Above the threshold, ESL at all frequencies exceeds the baseline reference frequency, preventing the calculation of AF. The resulting probabilistic distribution of AF is insensitive to SLR above the threshold. These features detrimentally impact the utility of AF as a hazard metric. Frechet distributions are appropriate and commonly used for ESL in tropical cyclone regions, but AFs applied to such distributions must interpreted with caution. In such regions, coastal risk managers should consider other flood hazard metrics, such as probabilistic estimates of flood depth.
Reconstruction of July-September standardized precipitation-evapotranspiration index (SPEI) for the Hindu Kush region of Northern Pakistan
Authors: Asad Fayaz , Adil Muhammad , Khan Nasrullah , Rao Mukund Palat , Alrefaei Abdulwahed Fahad , Almutairi Mikhlid H , Ali Sajid 
Published: April 2024

Abstract
The prolonged drought resulting from global warming is considered an important factor affecting West Asia’s socioeconomic growth, with a significant impact on the dynamic forecasting of water supply and forest ecosystems. In such a scenario, understanding historical long-term drought changes is crucial for accurately forecasting regional drought shifts in the Hindukush region. In this study, a 517-year (1506–2022 C.E.) long tree-ring width chronology of the Himalayan Cedar (Cedrus deodara D. Don) from the eastern Hindukush has been developed. The July-September Standardized Precipitation-Evapotranspiration Index (SPEI) has revealed a positive and significant relationship (r = 0.633, p < 0.001) with tree growth, which leads to SPEI reconstruction from AD 1626 in the Hindu Kush region. Our reconstruction model has explained 40.1% of the climate variance during the instrumental period from C.E. 1965 to 2018. Fourteen wet periods (≥ 3 years) were observed before the instrumental period, specifically in C.E. 1629–1635, 1638–1658, 1666–1674, 1680–1701, 1715–1724, 1770–1776, 1794–1797, 1802–1810, 1822–1846, 1850–1857, 1872–1881, 1883–1890, 1906–1914, and 1921–1937. Similarly, twelve dry summer periods were also observed in the past 339 years, such as C.E. 1659–1665, 1675–1679, 1702–1714, 1725–1769, 1777–1793, 1798–1801, 1811–1821, 1847–1849, 1858–1871, 1891–1905, 1915–1920, and 1938–1963. Nevertheless, AD 1663 was individually the wettest (with a value of 2.13), while AD 1754 was the driest (−0.99) year. The spatial correlation analysis and its comparisons with Karakoram-Himalayan drought and precipitation reconstructions have convincingly confirmed the reliability of our SPEI reconstruction. Consequently, this reconstruction can effectively serve as a proxy for large-scale drought variability in the Hindu Kush region of northern Pakistan. Our findings strongly suggest the considerable dendrochronological potential for further climatological studies in the western Hindu Kush Mountains System.
Optimized virtual impedance solar restoration droop emulated SEPIC controller under low irradiation
Authors: Yadav Mukhraj , Singh Navdeep 
Published: April 2024

Abstract
This paper is focused on PV-based reduced order pade’s approximation SEPIC (single-ended primary inductor converter) virtual Impedance, restoration controller with parallel impedance emulation condition. However, the complexity of the higher-order SEPIC controller has been reduced and compared using Pade’s approximation with different reduction techniques. It covers the time response, oscillation, overshoot, dynamic performance, and controller stability. The computational time and need of the sensor are less, and better responses occur compared to the other reduction technique under the solar irradiance variation. However, in PV, the dynamic resistance is generalized by a nonlinear solar I–V (current–voltage) curve dependent on the operating point, such as irradiance, temperature, and its I–V curve. The nonlinearity effect affects the stability of the system. The SEPIC outer voltage and inner current controller with virtual impedance controller enhance the stability, and comparative response is demonstrated through the bode plot. A virtual impedance controller (VIC) cascaded with voltage restoration minimizes the voltage notching and oscillations under variation of inertia coefficients. The transient and dynamic performance of reduced order using a genetic algorithm controller has been used to demonstrate and discuss the PV-SEPIC system’s stability.
Low-loss carrier stored trench-gate bipolar transistor with split-gate optimization
Authors: Tan Jingjing , Xu Hang , Chen Lin , Sun Qingqing , Zhu Hao 
Published: April 2024

Abstract
In the conventional carrier stored trench-gate bipolar transistor (CSTBT) device, a lower conduction voltage drop (Von) can be achieved with higher carrier stored (CS) layer dosage. However, the trench bottom is weakened leading to easier breakdown under high electrical field. In this work, the trench-gate structure of the conventional CSTBT is optimized and split into three components. The bottom and top left components of the split trench structure are equipotential with the emitter, which effectively eliminated the impact of collector on the trench gate with reduced gate charge (Qgc). In addition, another n-type CS layer is formed adjacent to the emitter to further enhance the hole carrier storage effect near emitter. This improves the trade-off between Von and turn-off time (Toff) without breakdown voltage (BV) degradation. The simulation results show that in comparison with the conventional CSTBT, the proposed device exhibits 64.6% reduction in Qgc under the same Von, while the turn-off time (Toff) and the saturation current are reduced by 14.9% and 43.4%, respectively. The short-circuit capability is also studied with 2.83 times improvement. Our proposed device shown here provides a feasible and attractive approach for advanced high-performance power electronics applications.
Spiral wave dynamics in a neuronal network model
Authors: Souza Diogo L M , Borges Fernando S , Gabrick Enrique C , Bentivoglio Lucas E , Protachevicz Paulo R , dos Santos Vagner , Viana Ricardo L , Caldas Ibere L , Iarosz Kelly C , Batista Antonio M , Kurths Jürgen 
Published: April 2024

Abstract
Spiral waves are spatial-temporal patterns that can emerge in different systems as heart tissues, chemical oscillators, ecological networks and the brain. These waves have been identified in the neocortex of turtles, rats, and humans, particularly during sleep-like states. Although their functions in cognitive activities remain until now poorly understood, these patterns are related to cortical activity modulation and contribute to cortical processing. In this work, ,we construct a neuronal network layer based on the spatial distribution of pyramidal neurons. Our main goal is to investigate how local connectivity and coupling strength are associated with the emergence of spiral waves. Therefore, we propose a trustworthy method capable of detecting different wave patterns, based on local and global phase order parameters. As a result, we find that the range of connection radius (R) plays a crucial role in the appearance of spiral waves. For R < 20 µm, only asynchronous activity is observed due to small number of connections. The coupling strength (

g
syn

) greatly influences the pattern transitions for higher R, where spikes and bursts firing patterns can be observed in spiral and non-spiral waves. Finally, we show that for some values of R and

g
syn

bistable states of wave patterns are obtained.