bluuebunny/crossref_metadata_2025 huggingface dataset:
PageRank talent mining algorithm of power system based on cognitive load and DPCNN
Authors: Feng Kan , Yang Changliang , Zhu Wenqiang , Li Kun , Chen Ya
Published: January 2024

PageRank talent mining in power system is an effective means for enterprises to recruit talents, which can correctly recommend talents in practical applications. At present, the mining evaluation index system is not perfect, and the consistency coefficient between the evaluation results and the actual situation is low in practical applications. Therefore, PageRank talent mining algorithm in power system based on cognitive load and dilated convolutional neural network (DPCNN) is proposed. The cognitive load and DPCNN are used to establish a talent capability evaluation system, calculate the index weight value, construct the PageRank talent capability evaluation model of the power system according to the corresponding weight of the index, determine the membership range of the index, calculate the comprehensive score of the appraiser's ability, and determine the ability level of the appraiser, thus realizing the PageRank talent mining algorithm of the power system. The experimental results show that the algorithm has high accuracy and objectivity, good encryption effect, cannot crack the attack node, the prediction error and the prediction relative error are closest to the standard value, the maximum error is 0.51, the maximum relative error is 0.82, and can achieve the accurate prediction of talent demand.
Lyman continuum leaker candidates at z ∼ 3–4 in the HDUV based on a spectroscopic sample of MUSE LAEs
Authors: Kerutt J. , Oesch P. A. , Wisotzki L. , Verhamme A. , Atek H. , Herenz E. C. , Illingworth G. D. , Kusakabe H. , Matthee J. , Mauerhofer V. , Montes M. , Naidu R. P. , Nelson E. , Reddy N. , Schaye J. , Simmonds C. , Urrutia T. , Vitte E.
Published: January 2024

Context. In recent years, a number of Lyman continuum (LyC) leaker candidates have been found at intermediate redshifts, providing insight into how the Universe was reionised at early cosmic times. There are now around 100 known LyC leakers at all redshifts, which enables us to analyse their properties statistically.

Aims. Here, we identify new LyC leaker candidates at z ≈ 3 − 4.5 and compare them to objects from the literature to get an overview of the different observed escape fractions and their relation to the properties of the Lyman α (Lyα) emission line. The aim of this work is to test the indicators (or proxies) for LyC leakage suggested in the literature and to improve our understanding of the kinds of galaxies from which LyC radiation can escape.

Methods. We used data from the Hubble Deep Ultraviolet (HDUV) legacy survey to search for LyC emission based on a sample of ≈2000 Lyα emitters (LAEs) detected previously in two surveys with the Multi-Unit Spectroscopic Explorer (MUSE), namely MUSE-Deep and MUSE-Wide. Based on the redshifts and positions of the LAEs, we look for potential LyC leakage in the WFC3/UVIS F336W band of the HDUV survey. The escape fractions are measured and compared in different ways, including spectral energy distribution (SED) fitting performed using the CIGALE software.

Results. We add 12 objects to the sample of known LyC leaker candidates (5 highly likely leakers and 7 potential ones), 1 of which was previously known, and compare their Lyα properties to their escape fractions. We find escape fractions of between ∼20% and ∼90%, assuming a high transmission in the intergalactic medium (IGM). We present a method whereby the number of LyC leaker candidates we find is used to infer the underlying average escape fraction of galaxies, which is ≈12%.

Conclusion. Based on their Lyα properties, we conclude that LyC leakers are not very different from other high-z LAEs and suggest that most LAEs could be leaking LyC even if this cannot always be detected because of the direction of emission and the transmission properties of the IGM.
12CO+ and 13CO+ fluorescence models for measuring the 12C/13C isotopic ratio in comets
Authors: Rousselot P. , Jehin E. , Hutsemékers D. , Opitom C. , Manfroid J. , Hardy P.
Published: January 2024

Context. CO is an abundant species in comets, creating CO+ ion with emission lines that can be observed in the optical spectral range. A good modeling of its fluorescence spectrum is important for a better measurement of the CO+ abundance. Such a species, if abundant enough, can also be used to measure the 12C/13C isotopic ratio.

Aims. This study uses the opportunity of a high CO content observed in the comet C/2016 R2 (PanSTARRS), which created bright CO+ emission lines in the optical range, to build and test a new fluorescence model of this species and to measure the 12C/13C isotopic ratio in this chemical species for the first time with ground-based observations.

Methods. Thanks to laboratory data and theoretical works available in the scientific literature, we developed a new fluorescence model both for 12CO+ and 13CO+ ions. The 13CO+ model can be used for coadding faint emission lines and to obtain a sufficient signal-to-noise ratio to detect this isotopologue.

Results. Our fluorescence model provides a good modeling of the 12CO+ emission lines, allowing us to publish revised fluorescence efficiencies. Based on similar transition probabilities for 12CO+ and 13CO+, we derive a 12C/13C isotopic ratio of 73±20 for CO+ in comet C/2016 R2. This value is in agreement with the Solar System ratio of 89±2 within the error bars, but is also consistent with the 12C/13C ratio in local interstellar medium (68±15).
Pulsation modeling of the Cepheid Y Ophiuchi with RSP/MESA
Authors: Hocdé V. , Smolec R. , Moskalik P. , Singh Rathour R. , Ziółkowska O.
Published: January 2024

Context. Y Ophiuchi (Y Oph) is a classical Cepheid with a pulsation period of P = 17.12 days. This star is reported to be as dim as a Cepheid of about half its pulsation period and it exhibits a low radial velocity and light-curve amplitude. For these reasons, Y Oph is not used to calibrate period-luminosity (PL) relation and its distance remains uncertain.

Aims. Our objective is to conduct hydrodynamical pulsation modeling of Y Oph to derive its distance and provide a physical insight into its low amplitude and luminosity, constrained by an extensive set of observations.

Methods. We first performed a linear analysis on a grid of models using the hydrodynamical pulsation code MESA-RSP to find the combinations of mass, metallicity, effective temperature, and luminosity resulting in linear excitation of pulsations with period of about 17 days. Then, we performed non-linear computations to obtain the full-amplitude pulsations of these models. Last, we compare the results to a complete set of observations along the pulsation cycle, including the angular diameter obtained by interferometry, effective temperature, and radial velocity obtained by high-resolution spectroscopy, as well as the light curves in the VJHKSLM bands. We simultaneously adjusted the distance, the color excess and circumstellar envelope (CSE) model to fit the light curves and the angular diameter.

Results. We find that all pulsation models at high effective temperatures are in remarkable agreement with the observations along the pulsation cycle. This result suggests that the low amplitude of Y Oph may be explained by proximal location to the blue edge of the instability strip (IS). We also find that a pulsational mass of about 7 − 8 M⊙ is consistent with a non-canonical evolutionary model with moderate overshooting, PL relation and Gaia parallax. However, a much lower mass below 5 M⊙ is required to match Baade-Wesselink (BW) distance measurements from the literature. We show that the combination of the impact of the CSE on the photometry, together with a projection factor of about 1.5, explains the discrepant distance and luminosity values obtained from BW methods.

Conclusions. Our findings indicate that the small pulsation amplitude of Y Oph can be attributed to its proximity to the blue edge of the instability strip. Additionally, our analysis reveals that the distances obtained using the BW method are biased compared to Gaia, mainly due to the impact of circumstellar envelope on the photometries and a high p-factor close to 1.5. Despite these unique characteristics, Y Oph is a long-period classical Cepheid that holds potential for calibration of the PL relation in the Galaxy.
Evaporation ages: A new dating method for young star clusters
Authors: Pelkonen V.-M. , Miret-Roig N. , Padoan P.
Published: January 2024

Context. The ages of young star clusters are fundamental clocks to constrain the formation and evolution of pre-main-sequence stars and their protoplanetary disks and exoplanets. However, dating methods for very young clusters often disagree, casting doubts on the accuracy of the derived ages.

Aims. We propose a new method to derive the kinematic age of star clusters based on the evaporation ages of their stars.

Methods. The method was validated and calibrated using hundreds of clusters identified in a supernova-driven simulation of the interstellar medium forming stars for approximately 40 Myr within a 250 pc region.

Results. We demonstrate that the clusters’ evaporation-age uncertainty can be as small as about 10% for clusters with a large enough number of evaporated stars and small but with realistic observational errors. We have obtained evaporation ages for a pilot sample of ten clusters, finding a good agreement with their published isochronal ages.

Conclusions. The evaporation ages will provide important constraints for modeling the pre-main-sequence evolution of low-mass stars, as well as allow for the star formation and gas-evaporation history of young clusters to be investigated. These ages can be more accurate than isochronal ages for very young clusters, for which observations and models are more uncertain.
A Robust and Risk-Averse Medical Waste Chain Network Design by considering Viability requirements
Authors: Lotfi Reza , Mardani Nooshin , Ali Sadia Samar , Pahlevan Seyedeh Maryam , Reza Davoodi Sayyed Mohammad
Published: January 2024

This research suggests a Robust and Risk-Averse Medical Waste Chain Network Design by considering Viability requirements (RRMWCNDV). The aim is to locate a waste management facility that minimizes waste and promotes the recycling of materials like metal and plastic, contributing to environmental benefits. The proposed RRMWCNDV aims to be viable, robust and risk-averse. A two-stage robust stochastic programming model was utilized to develop this framework. It incorporates risk by employing the Weighted Value at Risk (WVaR) approach for the first time. The study reveals that incorporating risk and robustness scenarios results in a lower cost function. The degree of conservatism in decision-making can be adjusted between 0% and 100%, increasing the cost function. The confidence level in WVaR indicates risk aversion, with an increase in the cost function with a 4% increase. The agility coefficient, which indicates the percentage of waste demand production from HC transferred to another facility, also affects the cost function and population risk. A decrease in the sustainability coefficient results in a 53% rise in the cost function and a 12.82% increase in population risk. The model demonstrates NP-hard characteristics and becomes exponentially complex for larger scales.
Polydiacetylene Micelles in Nanomedicine and Beyond
Authors: Gravel Edmond , Doris Eric , Demeese Céline
Published: January 2024

In this account article, we give an overview of our contribution to the development of stable micellar carriers obtained by self-assembly and photo-polymerization of diacetylenic amphiphiles. The stabilized micelles can be loaded with active substances and used for diagnostic and therapeutic applications, or loaded with a metal catalyst to promote some synthetic transformations in fully aqueous medium.

Table of content

1 Introduction

2 Polydiacetylene Micelles Applied to Nanomedicine

2.1 From Amphiphilic Units to Micelles

2.2 In vivo Behavior of Micelles

2.3 Passive Targeting of Tumors with Micelles

2.4 Drug Delivery with Micelles

2.5 Towards Improved Delivery of Micelles to Tumors Using Sonoporation

2.6 Active Targeting with Micelles

2.7 Behavior of Micelles at the Cellular Level and Potential Cytotoxicity

2.8 Micelles for siRNA Transfection

3 Polydiacetylene Micelles Applied to Catalysis

3.1 Copper Nanoparticles in Micelles

3.2 Copper Salts in Micelles

4 Conclusion
Model study of the protein-ligand binding in the development of hypersensitivity to folic acid and its analogs
Authors: Khmil N. V. , Kolesnikov V. G.
Published: January 2024

Folic acid (FA) plays a vital role in various metabolic processes, including synthesis and repair of DNA, cell division, the production of red blood cells, and fetal development. However, hypersensitivity to FA and its analogs can occur, leading to various symptomatic manifestations, including shortness of breath, skin rashes, itching, hives, swelling, gastrointestinal disturbances, tachycardia, and anaphylaxis. The mechanism of hypersensitivity to FA and its analogs is not well understood. However, it is known that human serum albumin (HSA) serves as a major pharmacokinetic effector for many substances and drugs, including FA and its analogs such as 5-methyltetrahydrofolic acid (5-MTHF), tetrahydrofolic acid (THFA), and methotrexate (MTX). HSA can interact with these compounds, affecting their distribution and metabolism. The study aimed to study the energetic and topological characteristics of the non-covalent complexes formed between HSA and FA and its analogs in order to obtain more complete information about the potential mechanisms involved in hypersensitivity reactions. Molecular docking was applied to search for the most energetically favorable conformations of the protein-ligand complexes and score the geometries based on their lowest binding energy. The 3D structure of HSA (PDB ID: 1AO6) was used as the docking target, which was obtained from the protein database. The structures of the ligands (FA, 5-MTHF, THFA, and MTX) were downloaded from PubChem, an open chemistry database at the National Institutes of Health. The surface area, volume, and depth of the binding pocket were determined using Proteins Plus. The identification of non-covalent interactions between HSA and the ligands was carried out using the PoseView and DoGSiteScorer web tools. It has been demonstrated that hydrophobic interactions and hydrogen bonds predominantly stabilize all the studied HSA-ligand complexes. Molecular docking analysis revealed that HSA binds the ligands within subdomains IB, IIA, and IIIA, with a binding energy of less than –10.0 kcal/mol. Identifying specific binding sites within the new antigen structures (the complex of HSA with the ligands) can be valuable in determining the energetically favorable binding of epitopes from these antigens to the active sites of IgE antibodies or immune cell receptors.
The effect of biologically active substances on BSA and on the textures of films obtained by drying water-salt solutions of BSA
Authors: Gorobchenko O. A. , Glibitskiy D. M. , Nikolov O. T. , Cheipesh T. A. , Dzhimieva T. N. , Zaitseva I. S. , Roshal A. D. , Semenov M. A. , Glibitskiy G. M.
Published: January 2024

In the previously published results, we studied the effect of flavin mononucleotide (FMN), sodium halides NaF and NaBr, iron chloride FeCl3 and aluminum chloride AlCl3 on zigzag patterns of films obtained from saline solutions of bovine serum albumin (BSA). Changes in the properties of the biopolymer and its aqueous environment in solutions were monitored by UV absorption and fluorescence spectroscopy, microwave dielectrometry and dynamic light scattering. This work summarizes the obtained results on the influence of components of various nature on BSA and its film textures. Changes in the parameters of zigzag patterns are associated with polydispersity due to the presence of colloidal particles, aggregates and FMN associates, as well as a decrease in the surface potential and BSA hydration. The possibility of predicting the character of the influence of the studied biologically active substances on BSA is analyzed.
Design of deeply cooled ultra-low dissipation amplifier and measuring cell for quantum measurements with a microwave single-photon counter
Authors: Turutanov O. G. , Korolev A. M. , Shnyrkov V. I. , Shapovalov A. P. , Baránek M. , Kern S. , Lyakhno V. Yu. , Neilinger P. , Grajcar M.
Published: January 2024

The requirements and details of designing a measuring cell and low-back-action deeply-cooled amplifier for quantum measurements at 10 mK are discussed. This equipment is a part of a microwave single-photon counter based on a superconducting flux qubit. The high-electron mobility transistors (HEMTs) in the amplifier operate in unsaturated microcurrent regime and dissipate only 1 μW of dc power per transistor. Simulated amplifier gain is 15 dB at 450 MHz with a high-impedance (≈ 5 kΩ) signal source and standard 50-Ω output.
New emission band of solid nitrogen
Authors: Savchenko E. V. , Khyzhniy I. V. , Uyutnov S. A. , Bludov M. A.
Published: January 2024

New results on the study of radiation effects in solid nitrogen and N2-doped Ne matrix are presented, with a focus on the so-called γ-line origin. The irradiation was carried out in dc regime with an electron beam of subthreshold energy. The relaxation dynamics was monitored by emission spectroscopy: cathodoluminescence (CL) and nonstationary luminescence (NsL), along with current activation spectroscopy. Thermally stimulated luminescence (TSL) and exoelectron emission (TSEE) of pure nitrogen and N2 in the Ne matrix were measured in a correlated manner. Three emission bands were recorded in the NIR CL spectra of solid N2: 794, 802, and 810 nm. The band at 810 nm was detected for the first time. These three bands are characterized by similar behavior and form molecular series with spacing between adjacent vibrational energy levels of the ground state of 125 and 123 cm−1. These data cast doubt on the recently made assumption that the γ-line is attributed to the emission of the nitrogen anion N− [R. E. Boltnev, I. B. Bykhalo, I. N. Krushinskaya et al. Phys. Chem. Chem. Phys. 18, 16013 (2016)]. The processes of electron attachment and neutralization of positively charged species are discussed. It has been established that the γ-line in the TSL spectra of pure nitrogen and N2-doped Ne matrix correlates with TSEE currents and recombination emission of O+, N2+, and N4+ ions, which indicates its connection with the neutralization reaction. The measurement of NsL supported this conclusion. A new possible assignment of the γ-line and its satellites to the emission of tetranitrogen N4 is discussed.
Selective uptake and desorption of carbon dioxide in carbon honeycombs of different sizes
Authors: Krainyukova N. V. , Diachenko D. G. , Kotomin E. A.
Published: January 2024

Carbon honeycombs (CHs) are new carbon cellular structures, very promising in many respects, in particular, for high-capacity storage of various materials, especially in gaseous and liquid forms. In this study, we report a strong uptake of carbon dioxide kept inside carbon honeycomb matrices up to temperatures about three times higher as compared with CO2 desorption at ≈ 90 K from flat solid surfaces in vacuum where we conduct our high-energy electron diffraction experiments. Desorption of CO2 from CH matrices upon heating exhibits non-monotone behavior, which is ascribed to carbon dioxide release from CH channels of different sizes. It is shown that modeling of CO2 uptake, storage, and redistribution in the thin CH channels of certain types and orientations upon heating can explain experimental observations.
Analytical energy formalism and kinetic effects of grain boundaries: A case study of graphene
Authors: Liu Cheng-yan , Li Zhi-ming , Gong Xin-gao
Published: January 2024

Grain boundaries (GBs), inherent in polycrystalline materials, manifest a diverse array of features that substantially affect material properties. However, the incomplete knowledge of the relevance between structures and energetics of GBs impedes the understanding of their effects. Here, taking graphene as an example, we propose an analytical energy formula for GBs in grain-boundary angle space. Our study reveals that any given GB can be characterized by a geometric combination of symmetric GBs, adhering to the principle of uniformly distributing their dislocation cores along straight trajectories. The formation probability of GBs, as predicted by our theoretical derivation, aligns well with both high-throughput calculations and experimental statistics. Furthermore, we unveil the elusive kinetic effects on GBs by contrasting experimental statistics with energy-dependent thermodynamic effects. This study not only presents a robust model to describe energetically favorable GBs in graphene, offering insight into the formation of GBs in two-dimensional materials, but also reveals the kinetic effects of GBs in material synthesizing process.
Viscoelastic vapor bubble collapse near solid walls and corresponding shock wave formation
Authors: Lang Christian , Adami Stefan , Adams Nikolaus A.
Published: January 2024

This study investigates the influence of viscoelasticity on the collapse of aspherical vapor bubbles near a solid boundary through numerical simulations. A fully compressible three-dimensional finite volume method is employed, incorporating a single-fluid homogeneous mixture cavitation model and the simplified linear Phan-Thien Tanner viscoelastic constitutive model. The collapse dynamics, liquid jetting, shock wave formation, and associated pressure impact are analyzed, and the viscous and viscoelastic stress fields are presented. A comparison of viscoelastic to Newtonian dynamics reveals significant differences in collapse behavior and shock wave formation due to viscoelasticity. Viscoelasticity can induce jet piercing, which is not observed in the Newtonian collapse, and increases vapor re-evaporation after the first collapse. The effect of changing the initial standoff distance is examined for both viscoelastic and Newtonian fluids, where a second jet formation is present only for the viscoelastic collapse, and the second collapse's intensity is increased due to increased vapor production during rebound. Additionally, the variation of elasticity in the viscoelastic case demonstrates a correlation between the amount of vapor produced during rebound and the relaxation time for the investigated cases.
A liquid crystal-based multi-bit terahertz reconfigurable intelligent surface
Authors: Shen Ze , Li Weili , Jin Biaobing , Zhao Dixian
Published: January 2024

Recently, the growing interest in reconfigurable intelligent surface (RIS) technology has spurred extensive research on its utilization in the terahertz (THz) regime. The reconfiguration of the THz field empowered by the RIS holds great significance for various practical RIS-aided implementations at THz frequencies. In this study, we present a multi-bit liquid crystal-based RIS that allows for the programmable control of THz waves. The proposed RIS is characterized by an achievable 3-bit working state as well as a near 270° maximum phase shift around 0.28 THz. This high degree of freedom in manipulating the phase of the reflected field provides flexibility in terahertz spatial beam reconfigurations. We show that the terahertz single-beam pattern can be steered continuously from 5° to 55° toward the desired angles while also allowing the adjustment of the beam number and beamwidth. Through this demonstration, we aim to contribute to the advancement of RIS technologies in the terahertz regime, paving the way for various RIS-aided applications such as THz wireless communications and beyond.
Infrared spectroscopy of the α-hydroxyethyl radical isolated in cryogenic solid media
Authors: Zasimov Pavel V. , Volosatova Anastasia D. , Góbi Sándor , Keresztes Barbara , Tyurin Daniil A. , Feldman Vladimir I. , Tarczay György
Published: January 2024

The α-hydroxyethyl radical (CH3·CHOH, 2A) is a key intermediate in ethanol biochemistry, combustion, atmospheric chemistry, radiation chemistry, and astrochemistry. Experimental data on the vibrational spectrum of this radical are crucially important for reliable detection and understanding of the chemical dynamics of this species. This study represents the first detailed experimental report on the infrared absorption bands of the α-hydroxyethyl radical complemented by ab initio computations. The radical was generated in solid para-H2 and Xe matrices via the reactions of hydrogen atoms with matrix-isolated ethanol molecules and radiolysis of isolated ethanol molecules with x rays. The absorption bands with maxima at 3654.6, 3052.1, 1425.7, 1247.9, 1195.6 (1177.4), and 1048.4 cm−1, observed in para-H2 matrices appearing upon the H· atom reaction, were attributed to the OHstr, α-CHstr, CCstr, COstr + CCObend, COstr, and CCstr + CCObend vibrational modes of the CH3·CHOH radical, respectively. The absorption bands with the positions slightly red-shifted from those observed in para-H2 were detected in both the irradiated and post-irradiation annealed Xe matrices containing C2H5OH. The results of the experiments with the isotopically substituted ethanol molecules (CH3CD2OH and CD3CD2OH) and the quantum-chemical computations at the UCCSD(T)/L2a_3 level support the assignment. The photolysis with ultraviolet light (240–300 nm) results in the decay of the α-hydroxyethyl radical, yielding acetaldehyde and its isomer, vinyl alcohol. A comparison of the experimental and theoretical results suggests that the radical adopts the thermodynamically more stable anti-conformation in both matrices.
Enhancement of thermoelectric properties in Sr0.7Ba0.3Nb2O6−δ-based ceramics via nano-sized Ti as additive
Authors: Zhu Min , Zhang Nan , Ma Dandan , Yan Xiaobin , Zhan Faqi , Zheng Yuehong , Lu Xuefeng , La Peiqing
Published: January 2024

A series of Sr0.7Ba0.3Nb2O6−δ/x wt. % Ti (x = 1, 3, 5, and 10) composite ceramic thermoelectric materials were prepared, and the mechanism for improving their thermoelectric properties was explored. The experimental results demonstrate that nano-additive titanium powder undergoes oxidation to form TiO2 during sintering. However, under annealing in a reducing atmosphere, oxidation reactions further deplete the lattice oxygen, leading to an increased generation of oxygen vacancies and enhanced carrier concentration, ultimately leading to successful resistivity reduction. The samples consistently exhibit low thermal conductivity values below 2.0 W m−1 K−1 due to crystal defects, complex structure, and phonon scattering at the grain boundaries. The sample doped with 5 wt. %. Ti exhibits the lowest resistivity and highest PF value (409.3 μW/m K2 at 1073 K). Consequently, the figure of merit of Sr0.7Ba0.3Nb2O6−δ with 5 wt. % Ti attains its maximum value of 0.30 at 1073 K, representing a 50% increase compared to that of the undoped sample Sr0.7Ba0.3Nb2O6−δ (0.20 at 1073 K).
Stretchable and transparent nanopillar arrays for high-performance ultra-flexible organic photovoltaics
Authors: Kim Jae-hyun , Park Byoungwook , Song Seulki , Ahn Junyong , Jeong Jaebin , Nam Sang-Hyeon , Lee Seung-Hoon , Park Junyong , Park Sungjun
Published: January 2024

Ultra-flexible organic photovoltaic (OPV) devices are gaining recognition due to their lightweight, mechanical flexibility, and high productivity potential and are emerging as a notable alternative power source. Significant enhancements in material design and device architecture have facilitated a near 20% of power conversion efficiencies (PCEs). To elevate PCE further, the integration of soft optical elements is pivotal, enabling optimized photon utilization by minimizing reflection and augmenting the optical path through diffraction. In this research, we showcase an ultra-flexible energy harvesting system embedding thin, stretchable nanopillar arrays made of poly(dimethylsiloxane). The unique diffraction and interference from nanopillar arrays amplify the photogeneration of exciton pairs, which, in turn, boosts the current density of PM6:Y6 based OPV devices from 25.46 to 28.01 mA/cm2, resulting in a PCEmax of 15.92%. Furthermore, the exceptional flexibility of this mold was demonstrated on an ultra-flexible PM6:Y6 device, enduring 100% compressive strain through 1000 repeated tests. These results propose an advantageous approach for improving OPV efficiency without necessitating alterations to the inherent components or structures of the device.
Prediction of mean flow and over-tip shock distribution in pressure-driven tip leakage flows
Authors: Tang Xiaolong , Yang Xiaoquan , Wu Fei , Yang Mingsui
Published: January 2024

The flow across the blade tip clearance in turbomachinery is simplified as pressure-driven tip leakage flow (TLF) by isolating it from the mainstream. Based on schlieren visualization and numerical simulations, several common features of TLF are achieved. Consequently, a diffusion model is proposed to evaluate the mean flow and shock motions within the clearance. It takes into consideration the effects of relative wall motion by superposing a fully developed Couette flow. In addition, the over-tip shock waves are treated as repeated sawtooth wave to model the propagation. This approach enables quick and accurate evaluations of the meanflow and shock motions under configurations of stationery and moving casing wall. Given the flow variables at boundaries of the shock region, the meanflow and the evolution of the over-tip shock waves can be achieved instantly with an error less than 2%. Another advantage of this model is it can be non-intrusive. Hence, the challenges, arising from spatial constraints in direct measuring of TLF within the clearance, are surmounted. This is beneficial for locating the tip flow loss and the shock-induced heat load. Two flow mechanisms are unveiled from the predictions: (1) The strongest shock–boundary interaction accompanied by strong momentum exchange occurs above the separation bubble. (2) The oscillation of over-tip shock waves is self-sustained by a feedback loop formed by the pressure-side vortex shedding, shock generation, and shock–boundary interactions.
Strategy of Chinese energy companies in the world market of oilfield services and logistics services: Regional aspects
Authors: Guliyev Mushfig , Agarzayev Azer , Huseynova Lamiya , Huseynli Orkhan , Rustamova Samira
Published: January 2024

The aggravation of the problem of climate change, as well as the growth of carbon dioxide emissions, determines the increased interest of the scientific community in the development of effective methods to minimize the growing threats. The focus of scientists is China with its accelerated economic development, contributing to the growth of carbon dioxide emissions and other environmental problems. Global and regional trends are reflected in the strategies of China's largest energy companies, which confirm the relevance of the topic under study. The purpose of the article is to study the current performance of China's energy sector, their trends, and future forecasts, taking into account the strategies of the key players in the country's oilfield services market. The study used the following scientific methods: economic and statistical analysis, predictive methods, system-structural method, analysis, comparison method, observation, and description. As a result of the study, the key trends in the energy industry in China today were analyzed, and forecast values selected indicators by announced pledges scenario and stated policies scenario. The structure of supply and consumption by China of both energies from traditional sources and generated from renewable sources is studied. The regional structure of energy exports and imports by China is considered, and the country's main strategic partners are identified. The analysis of operating models and strategic directions of activity of the largest oilfield services companies in China—PetroChina and Sinopec—was carried out. Attention is paid to the problems of interaction between logistics and oilfield services companies, and ways to minimize such problems are proposed. The results of the study can be used by government representatives when planning further actions regarding the development of the energy industry.
Dissolution of Mg-enriched defects in implanted GaN and increased p-type dopant activation
Authors: Huynh K. , Wang Y. , Liao M. E. , Tweedie J. , Reddy P. , Breckenridge M. H. , Collazo R. , Sitar Z. , Sierakowski K. , Bockowski M. , Huang X. , Wojcik M. , Goorsky M. S.
Published: January 2024

Annealing Mg-implanted homoepitaxial GaN at temperatures above 1400 °C eliminates the formation of inversion domains and leads to improved dopant activation efficiency. Extended defects, in the form of inversion domains, contain electrically inactive Mg after post-implantation annealing at temperatures as high as 1300 °C (one GPa N2 overpressure), which results in a low dopant activation efficiency. Triple-axis x-ray data reveal that implant-induced strain is fully relieved after annealing at 1300 °C for 10 min, indicating that strain-inducing point defects formed during implantation have reconfigured and inversion domains are formed. However, annealing at temperatures of 1400–1500 °C (one GPa N2 overpressure) eliminates the presence of the inversion domains. While residual defects, such as dislocation loops, still exist after annealing at and above 1400 °C, chemical analysis at multiple dislocation loops shows no sign of Mg segregation. Meanwhile, an overall decreasing trend in the dislocation loop density is observed after annealing at the higher temperatures and longer times. Additionally, once inversion domains are formed and the samples are cooled to room temperature, they are shown to dissolve with subsequent annealing above 1400 °C. While such defects have been observed before, the important finding that such defects can be dissolved with a short, higher temperature step is key. Earlier work [Breckenridge et al., J. Appl. Phys. Lett. 118, 022101 (2021)] addressing electrical measurements of these types of samples showed that annealing at 1400 °C leads to a dopant activation efficiency that is an order of magnitude higher than that observed at 1300 °C. This work complements earlier work by identifying the inversion domains, which incorporate Mg, and points to the benefits, in terms of defect density and p-type dopant activation, of using higher temperature (>1400 °C) annealing cycles to activate Mg in GaN, even if the Mg-containing inversion domains had been formed during lower temperature annealing.
Fabrication of antireflective superhydrophobic coating for self-cleaning solar panels and study of energy efficiency
Authors: Mishra Abhilasha , Gill Fateh Singh , Bhatt Neha , Rathod Arun Pratap Singh , Rajput Akanksha
Published: January 2024

Dust accumulation on solar panels decreases its efficacy due to the reflection of radiation by dust particles, which further decreases the amount of radiation reaching the solar cells. Antireflective superhydrophobic coatings based on nano-silica and nano-titania were prepared and applied on glass slides and small solar panels for laboratory scale study. All the coated substrates showed hydrophobic to superhydrophobic nature as confirmed by the contact angle of water drops on the coated glass. Scanning electron microscopy and atomic force microscopy results confirmed the presence of nanostructures on coated surfaces, which was responsible for the superhydrophobic behavior. The coating was also found to be stable in acidic, neutral, and basic solutions and a slight change in contact angle was observed after dipping the coated glass in different pH solutions. The antireflective nature of coated solar panels was also observed, and it was found that the coated side of the solar panel showed less reflection of light compared to the uncoated side. The current–voltage curve (I–V curve) was plotted for uncoated and coated solar panels and, further, fill factor and efficiency were calculated. Dust repelling and cleaning efficiency were also evaluated, and it was found that different types of dust were easily removed from coated panels without leaving behind any scratch marks. From the results, it can be concluded that the antireflective and superhydrophobic coatings are simple and sustainable solutions for cleaner and more efficient solar panels.
Deep learning for airfoil aerodynamic-electromagnetic coupling optimization with random forest
Authors: Jin Shi-Yi , Chen Shu-Sheng , Feng Cong , Gao Zheng-Hong
Published: January 2024

Reducing the design variable space is crucial in multi-objective airfoil profile optimization to improve optimization efficiency and reduce computational costs. Based on random forest and deep neural networks (DNNs), this work performs range reduction on ten design variables obtained through a fourth-order class shape transformation parameterization method for subsonic airfoil profiles. Three aerodynamic performance objectives (lift coefficient, drag coefficient, and lift-to-drag ratio) are evaluated using the Reynolds-averaged Navier–Stokes equations, and two radar stealth performance objectives (horizontal and vertical polarization radar cross sections) are assessed through the method of moments. By combining a DNN architecture with an improved regression prediction capability, predictive models are trained for mapping design variables to design objectives. The prediction errors are below 3% for the aerodynamic performance design objectives and below 1% for the stealth performance design objectives. The particle swarm optimization algorithm provides optimized airfoil profiles for three scenarios. First is a higher lift coefficient with a lower radar cross section. Second is a lower radar cross section. Third is a higher lift coefficient. Increasing the airfoil curvature and reducing the maximum thickness improves the lift coefficient by 386 counts and reduces the drag coefficient by 17 counts. By curving the airfoil leading edge, the radar cross section for the transverse electric and transverse magnetic polarizations decreased by 2.78 and 2.09 dBsm, respectively.
Benchmarking the accuracy of the separable resolution of the identity approach for correlated methods in the numeric atom-centered orbitals framework
Authors: Delesma Francisco A. , Leucke Moritz , Golze Dorothea , Rinke Patrick
Published: January 2024

Four-center two-electron Coulomb integrals routinely appear in electronic structure algorithms. The resolution-of-the-identity (RI) is a popular technique to reduce the computational cost for the numerical evaluation of these integrals in localized basis-sets codes. Recently, Duchemin and Blase proposed a separable RI scheme [J. Chem. Phys. 150, 174120 (2019)], which preserves the accuracy of the standard global RI method with the Coulomb metric and permits the formulation of cubic-scaling random phase approximation (RPA) and GW approaches. Here, we present the implementation of a separable RI scheme within an all-electron numeric atom-centered orbital framework. We present comprehensive benchmark results using the Thiel and the GW100 test set. Our benchmarks include atomization energies from Hartree–Fock, second-order Møller–Plesset (MP2), coupled-cluster singles and doubles, RPA, and renormalized second-order perturbation theory, as well as quasiparticle energies from GW. We found that the separable RI approach reproduces RI-free HF calculations within 9 meV and MP2 calculations within 1 meV. We have confirmed that the separable RI error is independent of the system size by including disordered carbon clusters up to 116 atoms in our benchmarks.
Atomistic simulation of thermoelectric properties in cove-edged graphene nanoribbons
Authors: Xie Zhong-Xiang , Chen Xue-Kun , Yu Xia , Deng Yuan-Xiang , Zhang Yong , Zhou Wu-Xing , Jia Pin-Zhen
Published: January 2024

We present an atomistic simulation of thermoelectric properties in cove-edged graphene nanoribbons (CGNRs) via the nonequilibrium Green's function. Different from gapless zigzag graphene nanoribbons (ZGNRs), CGNRs exhibit a noticeable bandgap. Such a bandgap can be modulated by varying three structural parameters (namely, the width N, the distance between adjacent coves m, as well as the shortest offset n) of CGNRs, which can give rise to the transition from semiconducting to semi-metallic. Due to the less dispersive phonon bands and the decrease in the number of phonon channels of CGNRs, they are found to have the lower phonon thermal conductance than ZGNRs. Modulation of CGNRs can produce over tenfold improvement of the maximum of ZT compared to ZGNRs. This improvement is due to the promotion of the Seebeck coefficient together with the degradation of the phonon thermal conductance of CGNRs compared to ZGNRs.
An early detection indicator of combustion instability for an industrial gas turbine combustor
Authors: Fu Yanni , Zhang Yuming , Zang Peng , Sui Yongfeng , Zheng Yao , Xia Yifan
Published: January 2024

Detection of combustion instability is crucial for the safety and reliability of gas turbines. In this paper, the recurrence quantification analysis (RQA) and multi-fractal analysis (MFA) methods are applied to investigate the transition process from combustion noise to combustion instability in an industrial-scale combustor. Based on the dynamic pressure (DP) obtained from high pressure and high temperature tests, a novel method is proposed to construct early detection indicators (EDI) of combustion instability. The method is mainly based on the three-dimensional map of the recurrence rate, Hurst exponent, and root mean square ratio. A regression method and SVM are applied to define the classification boundary. For three test cases, the results showed that the proposed EDI can effectively detect the onset of combustion instability. Compared to the conventional method based on the root mean square levels of dynamic pressure, the EDI has capability to forecast the onset of combustion instability approximately a few hundred milliseconds in advance.
Studies of interfacial wave properties during displacement with pure viscoelastic fluids in microchannels
Authors: Hue Seng Hoe , Chagot Loïc , Angeli Panagiota
Published: January 2024

In this study, new experimental data for the displacement of a Newtonian liquid by three pure viscoelastic (Boger) fluids with different relaxation times were obtained with imaging in a 500 μm microchannel. Results were compared against those from displacement using a Newtonian liquid. Small irregular waves were observed at the interface for the Newtonian displacement, while periodic instabilities were seen for all Boger fluid cases. The elastic Mach number (Ma), describing the ratio of the flow velocity with the elastic wave propagation velocity, was found to be the key parameter for correlating the wave properties in the case of Boger fluids. The amplitude of the wavy interface initially increased up to Ma = 0.5, before decreasing again. The frequency and the wave velocity increased monotonically with increasing Ma. For all configurations, a phase shift of π was found between the top and the bottom interfaces. Correlations from experimental data were developed for all wave properties. Based on these correlations, an empirical wave model was developed to describe the observed planar images and to reconstruct the three-dimensional waves, which resemble a helical structure.
Topological photonics in three and higher dimensions
Authors: Han Ning , Xi Xiang , Meng Yan , Chen Hongsheng , Gao Zhen , Yang Yihao
Published: January 2024

Topological photonics is a rapidly developing field that leverages geometric and topological concepts to engineer and control the characteristics of light. Currently, the research on topological photonics has expanded from traditional one-dimensional (1D) and two-dimensional (2D) to three-dimensional (3D) and higher-dimensional spaces. However, most reviews on topological photonics focus on 1D and 2D systems, and a review that provides a detailed classification and introduction of 3D and higher-dimensional systems is still missing. Here, we review the photonic topological states in 3D and higher-dimensional systems on different platforms. Moreover, we discuss internal connections between different photonic topological phases and look forward to the future development direction and potential applications of 3D and higher-dimensional systems.
Interface-induced origin of Schottky-to-Ohmic-to-Schottky conversion in non-conventional contact to β-Ga2O3
Authors: Kaur Damanpreet , Dahiya Rohit , Shivani  , Kumar Mukesh
Published: January 2024

β-Ga2O3 is an emerging ultra-wide bandgap semiconductor with wide-ranging applications from civil to military realms. Due to the varied surface states and upward band-bending of β-Ga2O3 with most metals, most of the conventional metal contacts turn out to be Schottky in nature, leading to a paucity of suitable Ohmic contacts to Ga2O3. Transparent conducting oxides (TCOs) offer the flexibility of conduction along with optical transparency, useful especially for optoelectronic devices. Herein, we report on the use of indium-zinc oxide (IZO), a TCO, as a suitable, unconventional contact to β-Ga2O3. The devices show a unique conversion from Schottky to Ohmic by annealing at an optimized temperature of 650 °C, while changing back to Schottky at higher temperatures. At 650 °C, the interface chemistry as studied by x-ray photoelectron spectroscopy changes drastically with band-bending of β-Ga2O3 shifting from upward to downward at the interface leading to a type II band alignment, responsible for the Schottky-to-Ohmic conversion. The results provide evidence of using IZO layer as an alternate contact material to β-Ga2O3 whose behavior as Ohmic or Schottky contact may be tuned by simply varying the annealing temperature and inducing interfacial changes at the semiconductor–electrode interface, while maintaining excellent device resilience. The proposed conducting oxide layer provides an effective strategy toward control and tunability in nature of contacts toward gallium oxide and its applications for high temperature resilience solar-blind photodetectors.
Cortical
miR-709
links glutamatergic signaling to NREM sleep EEG slow waves in an activity-dependent manner
Authors: Kompotis Konstantinos , Mang Géraldine M. , Hubbard Jeffrey , Jimenez Sonia , Emmenegger Yann , Polysopoulos Christos , Hor Charlotte N. , Wigger Leonore , Hébert Sébastien S. , Mongrain Valérie , Franken Paul
Published: January 2024

MicroRNAs (miRNAs) are key post-transcriptional regulators of gene expression that have been implicated in a plethora of neuronal processes. Nevertheless, their role in regulating brain activity in the context of sleep has so far received little attention. To test their involvement, we deleted mature miRNAs in post-mitotic neurons at two developmental ages, i.e., in early adulthood using conditional
Dicer
knockout (cKO) mice and in adult mice using an inducible conditional
Dicer
cKO (icKO) line. In both models, electroencephalographic (EEG) activity was affected and the response to sleep deprivation (SD) altered; while the rapid-eye-movement sleep (REMS) rebound was compromised in both, the increase in EEG delta (1 to 4 Hz) power during non-REMS (NREMS) was smaller in cKO mice and larger in icKO mice compared to controls. We subsequently investigated the effects of SD on the forebrain miRNA transcriptome and found that the expression of 48 miRNAs was affected, and in particular that of the activity-dependent
miR-709
. In vivo inhibition of
miR-709
in the brain increased EEG power during NREMS in the slow-delta (0.75 to 1.75 Hz) range, particularly after periods of prolonged wakefulness. Transcriptome analysis of primary cortical neurons in vitro revealed that
miR-709
regulates genes involved in glutamatergic neurotransmission. A subset of these genes was also affected in the cortices of sleep-deprived,
miR-709
-inhibited mice. Our data implicate miRNAs in the regulation of EEG activity and indicate that
miR-709
links neuronal activity during wakefulness to brain synchrony during sleep through the regulation of glutamatergic signaling.