bluuebunny/crossref_metadata_2025 huggingface dataset:
Designing few-layered graphitic carbons with atomic-sized cobalt hydroxide by harnessing hollow metal–organic frameworks
Authors: Cho Eun Jin , Kim Bo-Min , Moon WooYeon , Park Dong Gyu , Ju Young-Wan , Choi Won Ho , Shin Jeeyoung
Published: September 2024

Graphitic carbon exhibits distinctive characteristics that can be modulated by varying the number of carbon layers.
Fine structural design and configuration regulation of DPP-based organic small molecule photovoltaic donors
Authors: Wang Xu , Liu Chang , Yin Lunxiang , Liu Yaru , Jiang Peiwen , Li Yanqin
Published: September 2024

Stille coupling reaction was used to prepare a series of six DPP-based organic small molecule photovoltaic donors. The results clearly demonstrate that optimization of photovoltaic performance can be achieved through rational structural design.
High-efficiency treatment of antibiotic wastewater by a self-assembled coated double-heterojunction TiO2/g-C3N4/BN photocatalyst
Authors: Yang Tiantian , Gao Tong , Fan Jiangtao , Zhang Linnan
Published: September 2024

The treatment of antibiotic wastewater is one of the environmental problems that humans must solve.
Porous organic polymers with spiro-thioketal linkages for effective iodine capture
Authors: Lu Wen-Jun , Ma Yu-Heng , Sun Bai-Wang
Published: September 2024

The thiol-aldehyde polycondensation reaction was employed to synthesize novel spiro-thioketal-based porous organic polymers. At 75 °C, iodine uptake capacities of POPSPs were measured as 4.13, 5.25, and 5.65 g g−1, respectively.
Regulation of daptomycin biosynthesis in Streptomyces roseosporus: new insights from genomic analysis and synthetic biology to accelerate lipopeptide discovery and commercial production
Authors: Baltz Richard H.
Published: September 2024

Complex regulatory mechanisms govern daptomycin biosynthesis in Streptomyces roseosporus. Ten regulatory genes modulate transcription of daptomycin biosynthetic genes from a single promoter, and translation is coordinated by translational coupling.
Visualizing and quantifying dynamic cellular forces with photonic crystal hydrogels
Authors: Zhou Jiankang , Zhang Ying , Fu Yifu , Li Qiwei , Zhang Jiajia , Liu Xiaojiang , Gu Zhongze
Published: September 2024

A Photonic Crystal Force Microscopy (PCCFM) system, comprising a photonic crystal substrate (PCS) and a common microscope, enables real-time, high-throughput visualization and quantification of cellular forces.
Advanced approaches in skin wound healing – a review on the multifunctional properties of MXenes in therapy and sensing
Authors: Ferrara Valeria , Perfili Caterina , Artemi Giulia , Iacolino Brunella , Sciandra Francesca , Perini Giordano , Fusco Laura , Pogorielov Maksym , Delogu Lucia Gemma , Papi Massimiliano , De Spirito Marco , Palmieri Valentina
Published: September 2024

Used in hydrogels, patches, and smart bandages MXenes enhance antibacterial activity, promote tissue regeneration, and enable real-time monitoring, improving wound care and patient outcomes.
Synthetic routes to access dicarbonylated aryls and heteroaryls
Authors: Acharya Swadhin Swaraj , Parida Bibhuti Bhusan
Published: September 2024

The regioselective 1,2-dicarbonylation of aryls and heteroaryls offers access to functionalized dicarbonylated aryls and heteroaryls, which opens access to pharmaceuticals and bioactive molecules with diverse synthetic utility.
Block copolymer micelles as colloidal catalysts for photocatalytic NAD+ reduction
Authors: Eichhorn Jonas , Mengele Alexander K. , Neumann Christof , Biskupek Johannes , Turchanin Andrey , Kaiser Ute , Rau Sven , Schacher Felix H.
Published: September 2024

We herein report the preparation, characterization and (photo)catalytic investigation of block copolymer micelles featuring pendant bipyridyl rhodium complexes as NAD+ reduction catalyst and ruthenium polypyridyl complexes as photosensitizers.
Long-stable lithium metal batteries with a high-performance dual-salt solid polymer electrolyte
Authors: Gan Ling , Liang Yufeng , Feng Tingting , Li Huilan , Wu Mengqiang
Published: September 2024

A high-performance dual-salt solid polymer electrolyte, consisting of cross-linked NPGDA-VEC copolymer interpenetrated in a PVDF-HFP nanofiber matrix, with LiTFSI and LiBOB as Li+ sources, was prepared for lithium metal battery applications.
Sb2S3/AlGaAs-based reconfigurable metasurface for dynamic polarization and directionality control of quantum emitter emission
Authors: Karim Md. Ehsanul , Choudhury Sajid Muhaimin
Published: September 2024

Phase change material-based reconfigurable metasurfaces, utilizing a hybrid plasmon-quantum emitter coupled bullseye grating system are designed for tailoring different degrees of freedom of quantum emitter emission: polarization and directionality.
Novel α-N-heterocyclic thiosemicarbazone complexes: synthesis, characterization, and antimicrobial of properties investigation
Authors: Nartop Dilek , Hasanoğlu Özkan Elvan , Öğütcü Hatice , Kurnaz Yetim Nurdan , Özdemir İnci
Published: September 2024

In this paper, eight novel α-N-heterocyclic thiosemicarbazone complexes were synthesized in search of new biologically active compounds, and characterized via1H-NMR, IR, TGA, UV-Vis, molar conductance and magnetic susceptibility measurements.
Efficient energy and memory storage capabilities in optimized BiFeO3/MnMoO4/NiFe2O4 triphasic composites for futuristic multistate devices
Authors: Sagheer Izhar , Ansar Muhammad Tamoor , Ramay Shahid M. , Huang Houbing , Atiq Shahid
Published: September 2024

The emergence of multiferroic materials particularly bismuth iron oxide (BiFeO3) with distinctive magnetoelectric, and high energy storage capabilities, present pivotal aspects for next-generation memory storage devices.
Evaluation of optimized conditions for the adsorption of malachite green by SnO2-modified sugarcane bagasse biochar nanocomposites
Authors: Sharma Pramila , Sharma Shobhana , Sharma Sushil Kumar , Yifei Shao , Guo Fangqin , Ichikawa Takayuki , Jain Ankur , Shrivastava Kriti
Published: September 2024

Study of synthetic route and evaluation of kinetic and thermodynamic parameters of SnO2-SBB nanocomposites.
π-extended pyrenes: from an antiaromatic buckybowl to doubly curved nanocarbons with gulf architectures
Authors: Liu Binbin , Jin Zhengxiong , Liu Xinyue , Sun Lanfei , Yang Cao , Zhang Lei
Published: September 2024

An antiaromatic buckybowl and two doubly curved nanocarbons by fusion of nonbenzenoid rings onto pyrene have been synthesized and characterized.
Making an inverted Keggin ion lacunary
Authors: Liu Lu-Lu , Xu Zi-Yu , Yi Peng , Chen Chao-Qin , Lang Zhong-Ling , Yang Peng
Published: September 2024

After a hundred years of waiting, the use of binary heterogroups has succeeded in making an inverted Keggin ion lacunary, the enclosed Mo–oxo framework has been opened up with enhanced Lewis-acid–base catalytic activity.
Bifunctional PdMoPt trimetallene boosts alcohol–water electrolysis
Authors: Liu Junfeng , Li Tong , Wang Qiuxia , Liu Haiting , Wu Jingjing , Sui Yanping , Li Huaming , Tang Pengyi , Wang Yong
Published: September 2024

An alcohol–water hybrid electrolysis system using PdMoPt trimetallene as a bifunctional catalyst achieves low voltage input for energy-efficient hydrogen production.
Visible-light-driven asymmetric aldol reaction of ketones and glycinates via synergistic Lewis acid/photoredox catalysis
Authors: Tan Jiuqi , Yang Longqing , Su Hanyu , Yang Yuntian , Zhong Ziwei , Feng Xiaoming , Liu Xiaohua
Published: September 2024

We have synthesized β-diaryl-β-hydroxyl-α-amino acid derivatives through radical addition-type aldol reaction, which was confirmed by spectroscopic experiments, control experiments, and DFT calculations.
Electrosynthesis of NH3 from N2 using nanostructured Bi4Ti3O12 catalyst
Authors: Sebastian Meera , Das Subrata , Gopalan Nishanth Karimbintherikkal
Published: September 2024

Nanostructured Bi4Ti3O12 catalyst for electrosynthesis of NH3 at ambient conditions.
Simple and sustainable electric power generation by free evaporation of liquids from the surface of a conventional thermoelectric generator
Authors: Cheng Pengfei , Wang Dong , Schaaf Peter
Published: September 2024

Liquid evaporation on the surface of a thermoelectric generator can be applied for lighting up a bulb.
Validating the “greenness” of chemicals via life cycle assessment: the case of anisole as an anti-solvent in perovskite solar cells
Authors: Kamali A. Kamal , Keppetipola Nilanka M. , Yoshihara Yuka , Jena Ajay Kumar , Uchida Satoshi , Segawa Hiroshi , Sonnemann Guido , Toupance Thierry , Cojocaru Ludmila
Published: September 2024

Technological development is increasingly driven by environmental sustainability, with labels like ‘green’ gaining traction.
Photopatterning of conductive hydrogels which exhibit tissue-like properties
Authors: Sifringer Léo , De Windt Lina , Bernhard Stéphane , Amos Giulia , Clément Blandine , Duru Jens , Tibbitt Mark W. , Tringides Christina M.
Published: September 2024

Conductive hydrogels patterned with a confocal laser can produce complex shapes that support neuronal growth for over 7 weeks.
A versatile fluorescent probe for hydrogen peroxide in serotonergic neurons of living brains of mice with depression
Authors: Che Feida , Zhao Xiaoming , Ding Qi , Li Xiwei , Zhang Wen , Li Ping , Wang Xin , Tang Bo
Published: September 2024

Fluorescent probes target serotonin transporter and discern H2O2 in serotonergic neurons in living brains of mice.
An on-chip vacuum triode based on thermionic electron emission from super-aligned carbon nanotube films
Authors: He Yidan , Yao Jun , Zhao Yanqing , Liu Peng , Li Zhiwei , Wei Xianlong
Published: September 2024

An on-chip vacuum triode based on thermionic electron emission from suspended super-aligned carbon nanotube films is realized via microfabrication technology.
Revealing the structure and electronic characteristics of Te-rich threshold switching materials for high-density integration
Authors: Qiao Chong , Gu Rongchuan , Hu Shuangnian , Wang Guoxin , Wang Shengzhao , Gong Pei , Wang Songyou , Wang Cai-Zhuang , Xu Ming , Miao Xiangshui
Published: September 2024

Most Ge-centered tetrahedrons in amorphous GeTe6 are formed by stable Ge–Te bonds, ensuring the stability of amorphous configurations.
IC‐GraF: An Improved Clustering with Graph‐Embedding‐Based Features for Software Defect Prediction
Authors: Wang Xuanye , Lu Lu , Tian Qingyan , Lin Haishan
Published: September 2024

Software defect prediction (SDP) has been a prominent area of research in software engineering. Previous SDP methods often struggled in industrial applications, primarily due to the need for sufficient historical data. Thus, clustering‐based unsupervised defect prediction (CUDP) and cross‐project defect prediction (CPDP) emerged to address this challenge. However, the former exhibited limitations in capturing semantic and structural features, while the latter encountered constraints due to differences in data distribution across projects. Therefore, we introduce a novel framework called improved clustering with graph‐embedding‐based features (IC‐GraF) for SDP without the reliance on historical data. First, a preprocessing operation is performed to extract program dependence graphs (PDGs) and mark distinct dependency relationships within them. Second, the improved deep graph infomax (IDGI) model, an extension of the DGI model specifically for SDP, is designed to generate graph‐level representations of PDGs. Finally, a heuristic‐based k‐means clustering algorithm is employed to classify the features generated by IDGI. To validate the efficacy of IC‐GraF, we conduct experiments based on 24 releases of the PROMISE dataset, using F‐measure and G‐measure as evaluation criteria. The findings indicate that IC‐GraF achieves 5.0%−42.7% higher F‐measure, 5%−39.4% higher G‐measure, and 2.5%−11.4% higher AUC over existing CUDP methods. Even when compared with eight supervised learning‐based SDP methods, IC‐GraF maintains a superior competitive edge.
Uncoupled multimodal wave reflection from guide termination with different flanges: Experimental and numerical investigation
Authors: Marx David , Margnat Florent , Bailliet Hélène , Prax Christian , Qiu Zhiping , Valière Jean-Christophe
Published: September 2024

Reflection of propagating modes is studied at the exit of a cylindrical acoustic wave guide from both an experimental and a numerical point of view. The plane mode and several purely azimuthal higher modes are extracted by means of modal decomposition and the uncoupled reflection coefficients of each mode are obtained using two microphonic antennas for Helmholtz numbers below 5.3. The reflection at the open end of the guide is studied for different guide terminations: without flange, with a finite flange, with an infinite rigid flange. A numerical model based on finite elements is set to mimic the experimental protocol: generation of the acoustic wave by a locally vibrating wall (to represent the flush-mounted loudspeakers used in the experiments), computation of the acoustic field in a cylindrical duct geometry and radiation in open space (represented by a half sphere). Results are also compared with the theoretical predictions from the literature when available. For the plane mode, the difference between the three sources of data is less than 5%; overall, the agreement allows to discern an effect of termination for the plane mode and for the first higher mode. An end with finite flange leads to intermediate behaviours between without flange and with an infinite flange only for the reflection coefficient of the plane mode.
Persistent high-latitude ionospheric response to solar wind forcing
Authors: Borries Claudia , Iochem Pelin , Tasnim Samira , Davis Fredy
Published: September 2024

The solar wind continuously transfers energy into the Earth’s thermosphere-ionosphere system and variations in the solar wind properties modify the state of the system. The modifications are best visible during storm conditions when the ingestion of extreme amounts of solar wind energy into the thermosphere-ionosphere system causes global changes in thermosphere as well as large deviations in the ionospheric electron density from its quiet conditions. This study shows that there exists a persistent impact of the solar wind on the high-latitude electron density. A data set of 22 years of Total Electron Content (TEC) and 15 years of ionosonde data (critical frequency foF2 and height of maximum electron density hmF2) at Tromsø (70°N, 19°E) are used for correlation analyses with different solar wind parameters from OMNIWEB hourly “Near-Earth” solar wind magnetic field and plasma data. The results show that the ionospheric parameters systematically respond with an increase or decrease depending on local time, season, and solar cycle. TEC and foF2 increase with solar wind energy during winter night conditions and decrease with increasing solar wind energy during summer daytime. The summer negative ionospheric response is more intense during high solar activity conditions, while the winter positive ionospheric response is stronger during low solar activity. An anomaly is observed around 10 UT (noon) when TEC and foF2 respond with an increase during low solar activity conditions. Plasma convection, particle precipitation and Joule heating are the main drivers of the observed electron density changes at Tromsø. Local time, season, and solar cycle changes in the background ionosphere-thermosphere conditions lead to different effects of these driving processes. The results help to better understand the variability of the high-latitude electron density and show that solar wind forcing causes a systematic and persistent response of the ionosphere, which alternates depending on local time, season, and solar cycle.
Analysis of the impacts of reactant molecular beam velocity spreads on product velocity resolution in crossed beam experiments
Authors: Ding Yufan , Cheng Min , Gao Hong
Published: September 2024

Owing to its convenience and accuracy in providing detailed information about quantum state populations and angular distributions of reaction products, the velocity map imaging technique has been extensively employed in crossed beam experiments for product detection. In crossed beam experiments, the two reactant beams always exhibit certain spreads in both magnitude and direction of the velocity, which will blur the scattered product images and lower the resolution of product detection. To systematically investigate the influence of reactant velocity spreads on the resolution of product detection in crossed beam experiments, a general model based on velocity vector analysis is constructed and presented here. The impacts of spreads of the magnitude and direction of the reactant velocities on the image resolution under three typical experimental conditions are analyzed, and ways for improving the resolution are briefly discussed. Guided by the above analysis, a fine adjustment of the Ar+ ion beam was performed, and the product image resolution for the charge transfer reaction Ar+(2P3/2) + N2 is effectively improved, particularly in the backward scattering region, which provides more accurate information on the reaction dynamics.
Imaging photodissociation dynamics of excited SiO molecules at 193 nm with laser ablation supersonic beam
Authors: Ma Yujie , Li Fangfang , Yan Dong , Xu Ang , Zhou Ti , Liu Jiaxing , Wang Fengyan
Published: September 2024

SiO is a wide-spread molecule found in interstellar space. Previous research has primarily focused on its spectroscopy, while its photodissociation dynamics is elusive to study due to high dissociation energy. Using time-sliced ion velocity imaging technique, we observed the Si(3P)+O(3P) photodissociation process resulting from the excitation of highly vibrationally excited SiO(X1Σ+, υ=13–18) molecules to the SiO(A1Π, E1Σ+) states at 193 nm. The vibrationally excited SiO molecules were generated via laser ablation of silicon rod with the collision of the oxygen molecular beam acting as carrier gas and reaction gas. The bond dissociation energy De(Si–O) is determined to be 67253 ± 110 cm−1 (8.34 ± 0.01 eV) based on the kinetic energy distribution spectrum. The SiO photodissociation study has deepened our understanding of the mechanisms of silicon chemistry for silica-rich rocky meteors as they burn in the Earth's atmosphere, and the dissociation of SiO from ablation of meteoroids following ultraviolet photon absorption.
Mechanistic study of initial quenching process in photocatalytic α-keto acids radical acylation: A general strategy for enhancing quantum efficiency
Authors: Lin Zhicong , Li Jialu , Chen Chenli , Zhou Linan , Jie Jialong , Su Hongmei
Published: September 2024

The photocatalytic decarboxylation of α-keto acids to generate acyl radicals under mild conditions represents a novel strategy in organic synthesis. However, the quantum efficiency of this process has been underexplored, limiting its practicality. To improve quantum efficiency, detailed analysis of mechanisms and kinetic data for key steps are essential. In this work, using time-resolved emission and absorption spectroscopy, we conducted a mechanistic study focusing on the excited-state properties of representative photocatalysts and their quenching efficiencies during the initial quenching process ([Ir(dFCF3ppy)2(dtbbpy)]+ (IrIII), Eosin Y (EY), Rose Bengal (RB), and 4CzPN). Our findings revealed that RB is active in its triplet states (3RBH*), with lifetimes of 103 ns (in air) and 3.4 µs (in anaerobic conditions), while EY and 4CzPN are active in their singlet states (1EYH* and 14CzPN*), with lifetimes of 2.9 ns and 5.1 ns, respectively. We measured the second-order rate constants for quenching by electron transfer from α-keto acids: 1EYH*, 2.3 × 109 (mol/L)-1 · s−1; 3RBH*, 3.2 × 108 (mol/L)-1 · s−14CzPN*, 2.8 × 108 (mol/L)-1 · s−1. With our previously reported data for Mil, we established the quenching efficiency relationships for these photocatalysts with α-keto acids concentration. Our steady-state chromatography experiments determined the quantum efficiencies for consumption of α-keto acids (IrIII > RBH > EYH > 4CzPN), correlating these efficiencies with the initial quenching process. The results suggest that IrIII/RBH under anaerobic conditions could be optimal for high quantum efficiency. This study provides a foundation for designing new photocatalytic α-keto acid radical acylation systems with enhanced quantum efficiency.
Characteristics of fluctuations in the equatorial and polar directions of a compact dipole plasma driven at steady state
Authors: Hunjan Sargam , Bhattacharjee Sudeep
Published: September 2024

The fluctuations in the plasma potential (Vs̃) and electron density (Nẽ) are measured in the steady-state dipole plasma confined in a spherical vacuum chamber using a single permanent dipole magnet. Measurements are made from a radial distance r = 0.5–17 cm, from the surface of the magnet in the equatorial (θ=90°) and polar (θ=180°) directions, using a 4-pin probe setup, and have been characterized by power spectra, cross-phase, cross-coherence, induced transport, and energy spectra. The fluctuations are stronger near the surface of the dipole magnet for θ=90°, thereafter their magnitude decreases gradually with the radial distance. However, a peaked profile of potential fluctuations with the peak around r = 9 cm is observed for θ=180°. The locations of strong fluctuations are around the locations of smaller values of the electron neutral collision frequency. Frequency-resolved power spectra show that the fluctuations in the dipole plasma, predominantly, belong to the very low-frequency range. The values of cross-phase (≤45°) and |Vs̃/Te|/|Nẽ/Ne|≤1 indicate the presence of drift wave instability in both planes, where Te and Ne are equilibrium values of the electron temperature and density. The radial variation of fluctuation-induced electron flux (Γr) verifies the “inward diffusion” of electrons in the equatorial plane.
The development of a low-temperature terahertz scanning tunneling microscope based on a cryogen-free scheme
Authors: Zhang Huaiyu , Tian Dacheng , Zhan Yang , Liu Zijia , Ma Chen , Zhang Yuwu , Hu Jianwei , He Xiaoyue , Feng Baojie , Zhang Yiqi , Chen Lan , Cheng Peng , Wu Kehui
Published: September 2024

We have developed a cryogen-free, low-temperature terahertz scanning tunneling microscope (THz-STM). This system utilizes a continuous-flow cryogen-free cooler to achieve low temperatures of ∼25 K. Meanwhile, an ultra-small ultra-high vacuum chamber results in the reduction of the distance from sample to viewport to only 4 cm. NA = 0.6 can be achieved while placing the entire optical component, including a large parabolic mirror, outside the vacuum chamber. Thus, the convenience of optical coupling is much improved without compromising the performance of STM. Based on this, we introduced THz pulses into the tunnel junction and constructed the THz-STM, achieving atomic-level spatial resolution in THz-driven current imaging and sub-picosecond (sub-ps) time resolution in autocorrelation signals during pump–probe measurements. Experimental data from various representative samples are presented to showcase the performance of the instrument, establishing it as an ideal platform for studying non-equilibrium dynamic processes at nanoscale.
High temperature setup for measurement of Hall coefficient and electrical conductivity of thermoelectric materials
Authors: Agrawal B. , Choudhary S. , Sahu P. K. , Dasgupta T.
Published: September 2024

An experimental setup has been developed for the simultaneous measurement of the Hall coefficient (RH) and electrical conductivity (σ) of thermoelectric (TE) specimens in the temperature range of 300–700 K. The van der Pauw geometry is utilized for the RH and σ measurements. The sample holder geometry has been designed for diverse TE specimen dimensions and easy sample mounting. A special feature of the holder geometry is that the same sample can be used for other relevant thermoelectric measurements such as the Seebeck coefficient and thermal diffusivity. This minimizes measurement errors associated with compositional or doping inhomogeneities. In the absence of high temperature standard reference materials for Hall coefficient measurements, silicon samples with different doping concentrations have been used to verify the accuracy of the instrument. Additionally, the electrical conductivity data have been validated by measurements on the same samples in a calibrated setup. Repeat measurements indicate a maximum standard deviation of ±3% and ±0.5% for the RH and σ data in the studied temperature range. Furthermore, comparisons with the calibrated setup indicate deviations within ±3% for the σ data. The suitability of the measurement setup for TE specimens has been demonstrated using measurements on n-type (Mg2Sn) and p-type (Mg3Sb2) specimens with carrier concentrations in the range of 1019–1020 cm−3.
Josephson effect in a junction coupled to an electron reservoir
Authors: Beenakker C. W. J.
Published: September 2024

We extend the scattering theory of the Josephson effect to include a coupling of the Josephson junction to a gapless electron reservoir in the normal state. By opening up the system with a quasiparticle escape rate 1/τ, the supercurrent carried at zero temperature by an Andreev level at energy εA is reduced by a factor (2/π)arctan(2εAτ/ℏ). We make contact with recent work on “non-Hermitian Josephson junctions,” by comparing this result to different proposed generalizations of the Josephson effect to non-Hermitian Hamiltonians.
Elevating electron energy gain and betatron x-ray emission in proton-driven wakefield acceleration
Authors: Saberi Hossein , Xia Guoxing , Liang Linbo , Farmer John Patrick , Pukhov Alexander
Published: September 2024

The long proton beams present at CERN have the potential to evolve into a train of microbunches through the self-modulation instability process. The resonant wakefield generated by a periodic train of proton microbunches can establish a high acceleration field within the plasma, facilitating electron acceleration. This paper investigates the impact of plasma density on resonant wakefield excitation, thus influencing the acceleration of a witness electron bunch and its corresponding betatron radiation within the wakefield. Various scenarios involving different plasma densities are explored through particle-in-cell simulations. The peak wakefield in each scenario is calculated by considering a long pre-modulated proton driver with a fixed peak current. Subsequently, the study delves into the witness beam acceleration in the peak wakefield and its radiation emission. Elevated plasma density increases both the number of microbunches and the accelerating gradient of each microbunch, consequently resulting in heightened resonant wakefield. Nevertheless, the scaling is disrupted by the saturation of the resonant wakefield due to the nonlinearities. The simulation results reveal that at high plasma densities, an intense and broadband radiation spectrum extending into the domain of the hard x-rays and gamma rays is generated. Furthermore, in such instances, the energy gain of the witness beam is significantly enhanced. The impact of wakefield on the witness energy gain and the corresponding radiation spectrum is clearly evident at elevated densities.
Floating-point photonic iterative solver demonstrated for Newton–Raphson method
Authors: Klein Andrew B. , Zhu Zheyuan , Li Guifang , Pang Shuo
Published: September 2024

Though photonic computing systems offer advantages in speed, scalability, and power consumption, they often have a limited dynamic encoding range due to low signal-to-noise ratios. Compared to digital floating-point encoding, photonic fixed-point encoding limits the precision of photonic computing when applied to scientific problems. In the case of iterative algorithms such as those commonly applied in machine learning or differential equation solvers, techniques like precision decomposition and residue iteration can be applied to increase accuracy at a greater computing cost. However, the analog nature of photonic symbols allows for modulation of both amplitude and frequency, opening the possibility of encoding both the significand and exponent of floating-point values on photonic computing systems to expand the dynamic range without expending additional energy. With appropriate schema, element-wise floating-point multiplication can be performed intrinsically through the interference of light. Herein, we present a method for configurable, signed, floating-point encoding and multiplication on a limited precision photonic primitive consisting of a directly modulated Mach–Zehnder interferometer. We demonstrate this method using Newton's method to find the Golden Ratio within ±0.11%, with six-level exponent encoding for a signed trinary digit-equivalent significand, corresponding to an effective increase of 243× in the photonic primitive's dynamic range.
Global features of energetic proton pancake pitch angle distributions in the Earth's radiation belt
Authors: Hu Jiahui , Zou Zhengyang , Huang Hanyu , San Wen , Yuan Qitong , Zhu Beiqing
Published: September 2024

The temporal and spatial evolution of the energetic protons in the Earth's radiation belt is highly correlated with substorm activities. Understanding the variations of the pitch angle distributions (PADs) would be an important and convenient approach to better distinguish the dominant mechanisms. Based on Van Allen Probe observations from 2012 to 2019, the present study surveyed the energetic protons by fitting them as a function of  sin n∂ (where ∂ is the pitch angle and n is the fitted power-low index). The global distributions show that “typical” (n > 2) pancake PADs occur more frequently on the dayside (>95%) than on the nightside (<20%), showing a distinct day–night asymmetry. This asymmetry becomes much more pronounced for protons at higher energies, at higher L-shells, and during geomagnetic active times. Further investigations demonstrated that the commencement and disappearance of typical pancake PADs are mainly modulated by the plasmapause location. Moreover, “pronounced” (n > 5) and “extreme” (n > 10) pancake PADs can also be found at dayside at L > 5, with occurrence rates of up to 35% and 5%, respectively, during active times. The radial diffusion and magnetopause shadowing effects act as essential processes for increasing and decreasing the occurrence of pancake PADs. In addition, alternative mechanisms, such as wave–particle interactions led by plasma waves, are also important candidates. The present study provides a comprehensive analysis of the dependence of proton PADs on energy and geomagnetic storms, which would be useful for advanced radiation belt modeling.
Ex situ calibration of the scattered-light time-history diagnostic on the National Ignition Facility
Authors: Kostick S. , Filkins T. , Rosenberg M. J. , Katz J. , Theobald W. , Lemos N. , Tubman E. , Sommers R. , Hernandez J. E. , Swadling G. , Ross J. S. , Radha P. B. , Grullon F. , Heinmiller J. M. , Fornes J. , Hillyard P. , McCumber J. , Ceurvorst L. , Regan S. P.
Published: September 2024

The scattered-light time-history diagnostic (SLTD) suite measures time-resolved scattered light in three wavelength bands: stimulated Brillouin scattering (350–352 nm), stimulated Raman scattering (430–760 nm), and plasma emission at half the laser frequency (695–735 nm), at 15 locations around the National Ignition Facility (NIF) target chamber. The SLTD, along with the full-aperture backscatter station (FABS), collects scattered light from direct- and indirect-drive inertial confinement fusion experiments. The SLTD calibration was revisited after a discrepancy between FABS and SLTD measurements was observed on NIF polar direct-drive [Skupsky et al., Phys. Plasmas 11, 2763 (2004)] experiments. An integrated calibration of the SLTD was performed for the first time, and individual components were also calibrated for the wavelengths of 351, 527, and 532 nm. The optical transmission of the instrument was measured to be (1.12 ± 0.04) × 10−7 and (1.96 ± 0.11) × 10−7 for the wavelengths of 351 and 532 nm, respectively. The revised calibration at 351 nm brings the SLTD measured scattered energy in agreement with the FABS measured scattered energy after additionally accounting for the degradation of an optical element in FABS. This decreased the inferred absorption by 7% for a representative experiment. However, discrepancies remain between FABS and SLTD measurements in the SRS band (532 nm).
Integration of scanning probe microscope with high-performance computing: Fixed-policy and reward-driven workflows implementation
Authors: Liu Yu , Pratiush Utkarsh , Bemis Jason , Proksch Roger , Emery Reece , Rack Philip D. , Liu Yu-Chen , Yang Jan-Chi , Udovenko Stanislav , Trolier-McKinstry Susan , Kalinin Sergei V.
Published: September 2024

The rapid development of computation power and machine learning algorithms has paved the way for automating scientific discovery with a scanning probe microscope (SPM). The key elements toward operationalization of the automated SPM are the interface to enable SPM control from Python codes, availability of high computing power, and development of workflows for scientific discovery. Here, we build a Python interface library that enables controlling an SPM from either a local computer or a remote high-performance computer, which satisfies the high computation power need of machine learning algorithms in autonomous workflows. We further introduce a general platform to abstract the operations of SPM in scientific discovery into fixed-policy or reward-driven workflows. Our work provides a full infrastructure to build automated SPM workflows for both routine operations and autonomous scientific discovery with machine learning.
Density functional theory (DFT) study of water autoionization in solvated clusters
Authors: Kolasinski Kurt W. , Salkowski Alexa M.
Published: September 2024

We have implemented a cluster-continuum method using density functional theory to model water clusters and various charged species derived from water. The two aims of this study are to determine the minimal basis required for proper modeling of water autoionization and to determine the minimum number of explicit water molecules required to properly model the energetics of solvation. The thermodynamics of water autoionization converge following a modified power law to deliver chemically accurate values of the Gibbs energy change for autoionization with tractably small clusters. Convergence is slower and not exponential as assumed in previous work. We identify the n = 21 set of clusters as the first effectively bulk water like clusters that can capture the energetic influence of both the first and second solvation shells. In this cluster, a water molecule is encapsulated in the center of a closed shell of other water molecules that hydrogen bond to form five-membered rings. The total energy change for clusters with n ≥ 21 calculated using both the RPBE-D3 and ωB97X-D exchange–correlation functionals with the 6-311+G** basis set is shown to deliver good approximations to the free energy change at 298 K. This is true even though neither functional models the individual enthalpy or entropy contributions particularly well.
An X-band coaxial relativistic klystron oscillator with a novel diode structure packaged with permanent magnet
Authors: Li Zhimin , Zhang Peng , Ge Xingjun , Dang Fangchao , Yang Fuxiang , Chi Hang , Hu Xiaodong , Li Jiawen
Published: September 2024

To achieve compactness and miniaturization for high-power microwave devices, this paper proposes an X-band permanent magnet-packaged coaxial relativistic klystron oscillator (RKO) with a novel diode structure featuring a stair-step cathode. First, by adopting a large-radius anode structure, the emission of beam currents from the side of the cathode surface is diminished, thereby reducing the proportion of the backward current in the beam current from 10% to 7%. Second, a stair-step cathode is used to inhibit the return flow of electron beams from striking the anode and generating plasma. Concurrently, a radially non-uniform coaxial resonant cavity structure is employed to enhance the fundamental wave modulation depth of the electron beam and improve the beam–wave interaction's efficiency. The experimental results show that the novel device outputs a microwave with a frequency of 9.46 GHz and a pulse width of 55 ns. It generates a power output of 1.5 GW with an efficiency of approximately 30.5%, in the case in which the diode voltage is 505 kV, the beam current is 9.7 kA, and the guiding magnetic flux density is 0.4 T. This novel structure surpasses traditional diode configurations by enhancing the beam-to-wave conversion efficiency by roughly 10%, thereby offering substantial support for the compactness and miniaturization of RKO.
Realization of triple dispersion turning points in tapered seven-core fiber interferometer for sensitivity enhancement
Authors: Zhi Yanyan , Chen Hao , Hu Yanyu , Li Jie , Cao Yuan , Liang Hao , Wu Chuang , Guan Bai-Ou
Published: September 2024

Seven-core fibers have been widely applied in optical network, astronomy, and sensing applications. In this work, we report and demonstrate the existence of triple dispersion turning points of the super-mode interferences in a seven-core fiber spliced between two single-mode fibers by modifying the diameter of the multi-core fiber. The sensitivities of the interferometer on external variables, i.e., temperature, axial strain, and refractive index (RI), are measured, showing significant enhancement around the dispersion turning points. Compared to the regular multi-core fiber device without dimension modification, the sensitivities of temperature and axial strain are improved by about 60 times and 73 times around the dispersion turning points, respectively. While the regular device has no response to the external refractive index, the magnitude of RI sensitivity can reach as high as 33 459.0 nm/RIU in air, when the fiber diameter is modified to approach the dispersion turning point, enabling the discrimination of the refractive indices of N2 and CO2. The modification method of locating the modes at the dispersion turning points significantly enhances device sensitivity, providing an avenue for integrating ultra-sensitive sensors into commercial fiber networks.
Prediction–correction projection immersed interface method for interfacial stress-induced flows and applications to electrohydrodynamics
Authors: Chen Chong , Fan Yipeng , Xia Guangqing
Published: September 2024

We propose a robust, high-resolution prediction–correction projection immersed interface method (IIM) for solving the unsteady incompressible Navier–Stokes equations with traction boundary conditions, which arise from free surface flows driven by capillary, electric, and elastic forces. This method combines the advantages of traditional body-fitted moving mesh methods and immersed boundary methods (IBM), allowing for the accurate imposition of boundary conditions on free surfaces using Cartesian grids and providing detailed interface information that is typically smoothed out in traditional IBM. The irregular liquid-phase domain is embedded within a square region and discretized using a dynamically adaptive Cartesian mesh. The free surface is captured using a narrow-band level set with hybrid reinitialization. A prediction–correction projection scheme is constructed, incorporating additional pressure predictions and corrections to enhance robustness. The resulting Helmholtz/Poisson equations are solved using the augmented IIM for boundary value problems. Grid refinement analysis demonstrates second-order convergence of the L∞ error, even in challenging cases such as the oscillating drop test with low viscosity. We further apply this method to electrohydrodynamic (EHD) problems, constructing an implicit augmented IIM to solve the equations governing the electric field and charge conservation. Numerical experiments demonstrate that this method accurately addresses highly intense EHD phenomena, such as the formation of Taylor cones, highlighting its robustness.
Metasurface-based broadband full Stokes polarimeter with optimized simulation design
Authors: Zhao Jiaqi , Li Yingbo , Li Siqi , Wang Guoxi
Published: September 2024

A polarimeter, fundamental for characterizing the polarization state of light, is critical for advancing optical measurement techniques by delivering precise polarization information. A compact and portable polarimeter holds particular importance in applications like remote sensing and medical diagnosis. However, existing methods for developing a compact polarimeter are difficult to achieve full Stokes vector detection for broadband operation, and the noise immunity is also very weak. These defects significantly constrain the versatility of polarimeters across diverse application scenarios. Herein, a metadevice with dual-layer subwavelength grating structure for full Stokes vector detection has been proposed, capable of simultaneously achieving broadband detection and noise suppression. The intensity of the four elliptical polarization states of the incident light can be captured by four regions on this metadevice, enabling the computation of the full polarization state information via Mueller matrix inversion. Additionally, a set of optimized retardance at 0.73π and orientation angles at 43°, 80°, 111°, and 146° is provided to effectively suppress the noise. The results indicate that the recovery error remains below 5% across the 450–650 nm spectral range, showcasing a 1.5-fold enhancement in noise suppression capability compared to conventional structures.
Equation-of-motion regularized orbital-optimized second-order perturbation theory with the density-fitting approximation
Authors: Ünal Aslı , Bozkaya Uğur
Published: September 2024

The density-fitted equation-of-motion (EOM) orbital-optimized second-order perturbation theory (DF-EOM-OMP2) method is presented for the first time. In addition, κ-DF-EOM-MP2 and κ-DF-EOM-OMP2 methods are implemented with the addition of κ-regularization. The accuracy of the DF-EOM-OMP2, κ-DF-EOM-MP2, and κ-DF-EOM-OMP2 methods are compared to the density-fitted EOM-MP2 (DF-EOM-MP2), EOM coupled-cluster (CC) singles and doubles (DF-EOM-CCSD), and EOM-CCSD with the triples excitation correction model [EOM-CCSD(fT)] for excitation energies of many closed- and open-shell chemical systems. The excitation energies computed using different test cases and methods were compared to the EOM-CCSD(fT) method and mean absolute errors (MAEs) are presented. The MAE values of closed- and open-shell cases (closed-shell organic chromophores set, open-shell set, peptide radicals set, and radical set) according to the EOM-CCSD(fT) method show that the κ-regularization technique yields highly accurate results for the first excited states. Our results indicate that the κ-DF-EOM-MP2 and κ-DF-EOM-OMP2 methods perform noticeably better than the DF-EOM-MP2 and DF-EOM-OMP2 methods. They approach the EOM-CCSD quality, at a significantly reduced cost, for the computation of excitation energies. Especially, the κ-DF-EOM-MP2 method provides outstanding results for most test cases considered. Overall, we conclude that the κ-versions of DF-EOM-MP2 and DF-EOM-OMP2 emerge as a useful computational tool for the study of excited-state molecular properties.
Stimulated magnon scattering by non-degenerate parametric excitation
Authors: Kim Joo-Von , Merbouche Hugo
Published: September 2024

Parametric spin wave excitation allows studying a variety of nonlinear phenomena, such as magnon scattering. In patterned micro- and nanostructures, the magnon spectra is discrete and translational symmetry is broken, which means allowable scattering channels differ from those in continuous films. An example is non-degenerate scattering by which high-power transverse field pumping creates two magnons with distinct frequencies around half the pumping frequency. Through micromagnetics simulations, we show under certain conditions that combining two pumping frequencies generates new magnon modes through a process of stimulated magnon scattering. Such processes are found to depend on the film geometry and sequence of the pumping fields.
Influence and optimization of dual-orifice jet nozzles on oil capture performance of under-race lubrication with a radial oil scoop for high-speed bearings in aero-engine
Authors: Jiang Le , Liu Zhenxia , Huang Weina , Lyu Yaguo , Li Yanjun , Gao Wenjun , Liu Yewei
Published: September 2024

The objective of this research is to determine the influence of dual-orifice jet nozzles on the oil–air flow dynamics and oil capture performance in the under-race lubrication for high-speed bearings and to identify the optimal design parameter combinations for optimizing the oil capture performance. An experimental setup for under-race lubrication is specifically designed, complemented by a multiphase computational fluid dynamics model to elucidate the oil–air flow behavior. The response surface methodology is combined with a multi-objective particle swarm optimization algorithm to perform multi-objective optimization of the oil capture performance. The findings indicate that oil capture efficiency initially rises to a peak and subsequently declines with increasing orifice spacing, identifying an optimal orifice spacing that maximizes efficiency. While the oil flow rate from dual-orifice jet nozzles is lower than twice that of single-orifice jet nozzles, appropriate parameter matching allowed for an increase in both captured lubricant oil and efficiency. Optimized configurations achieved substantial enhancements in oil capture efficiency, with the greatest improvement exceeding 16%, all while maintaining precise oil supply to the high-speed bearings.
Analysis of the competitive influence of gas adsorption and interface modification on the surface free energy of coal matrix
Authors: Xu Chao , Yang Tong , Wang Kai , Wang Wenjing , Guo Lin
Published: September 2024

Coal is a complex porous medium characterized by numerous pores and fractures within its internal structure, which provide a natural space for the storage of coalbed methane. The high surface free energy of coal significantly inhibits the efficient extraction of coalbed methane, resulting in the escape of considerable amounts of greenhouse gas during the later stages of coal mining. This exacerbates the challenges and costs associated with environmental governance. According to the principle of minimum capacity, the surface of the coal matrix reduces its surface free energy through gas adsorption. To investigate the competitive influence of gas adsorption and interface modification on the surface free energy of the coal matrix, isothermal adsorption and contact angle determination experiments were conducted. The results indicate that as equilibrium pressure increases, the amount of gas adsorption on the surface of the coal matrix also increases, while the adsorption potential exhibits a contrasting trend. Under the influence of gas adsorption, there is a significant increase in Gibbs variation, indicating a substantial decrease in the surface free energy of the coal matrix. Under the influence of interface modification, an increase in surfactant concentration resulted in a trend of energy reduction characterized by an initial increase followed by a subsequent decrease. Moreover, interface modification effectively eliminated the water-blocking effect, leading to a significant enhancement in gas desorption. Consequently, interface modification offers important theoretical support for improving production in coalbed methane and mitigating the greenhouse effect.