bluuebunny/crossref_metadata_2025 huggingface dataset:
Two‐stage stochastic energy and reserve market clearing model considering real‐time offering strategy of renewable energy
Authors: Jiang Zhengting , Xiao Yunpeng , Xu Taishan , Liu Qi , Wang Jianxue
Published: November 2024

With the introduction of decarbonization policies worldwide, renewable energy, especially wind and solar power, is gradually taking a significant share in the power system. The two‐stage stochastic optimization methods are generally adopted to address the uncertainty issues and the two‐stage stochastic market clearing models are established with the participation of renewable energy. However, most existing two‐stage stochastic market clearing models usually intuitively presume the offering quantities of renewable energy are equal to their forecast values, neglecting the potential impacts of the strategic offerings on the market results and thus affecting the secure operation of power systems. To fill the gaps, this paper incorporates the strategic offering models of renewable energy into the two‐stage stochastic energy and reserve market clearing model. Within the two‐stage framework, the first day‐ahead stage serves for energy and reserve market clearing, while the second real‐time stage considers the adjustments on offering quantities of renewable energy according to the fluctuations of renewable generations. The two‐stage stochastic market clearing model is formulated as a mixed‐integer non‐linear programming problem, and an iterative algorithm is devised to obtain market clearing results after proper linearizations. The effectiveness of the proposed method is validated using the extended IEEE‐118 test system.
A small‐target traffic sign detection algorithm based on partial conv and atrous spatial pyramid
Authors: Li Yuqi , Wang Zijian , Zhang Han , Yao Xinpeng , Zhou Zhou , Cheng Xin
Published: November 2024

Traffic sign detection is essential to an intelligent driving assistance system. The deep learning‐based algorithm proposed in this paper aims to address the issue of low detection accuracy caused by the small size and high density of traffic signs in real‐world traffic scenarios. First, to improve the feature extraction module of the backbone network and to increase the model's ability to capture contextual information, partial convolution (PConv) is introduced. Second, to prevent information loss during the downsampling process, a cross‐stage atrous spatial pyramid (ASPPFCSPC) is constructed using atrous convolution. This method combines feature map information from various scales and expands the receptive field. Lastly, the small‐target detection precision is improved by incorporating an additional small‐target detection head, which uses high‐resolution feature maps for shallow features. The detection head is decoupled to extract the location and class information of the predicted target separately, thereby enhancing the generalization ability of the proposed model. Experiments have demonstrated the superiority of the proposed algorithm, as testing on the TT100K dataset resulted in a mAP@0.5 of 91.2% and a mAP@0.5:0.95 of 71.8% using the proposed algorithm.
Does the HCN/CO ratio trace the star-forming fraction of gas?
Authors: Bemis Ashley R. , Wilson Christine D. , Sharda Piyush , Roberts Ian D. , He Hao
Published: November 2024

We modeled emissivities of the HCN and CO J = 1–0 transitions across a grid of molecular cloud models encapsulating observed properties that span from normal star-forming galaxies to more extreme merging systems. These models are compared with archival observations of the HCN and CO J = 1–0 transitions, in addition to the radio continuum at 93 GHz, for ten nearby galaxies. We combined these model emissivities with the predictions of gravoturbulent models of star formation presented in the first paper in this series. In particular, we explored the impact of excitation and optical depth on CO and HCN emission and assess if the HCN/CO ratio tracks the fraction of gravitationally bound dense gas, fgrav, in molecular clouds. We find that our modeled HCN/CO ratios are consistent with the measurements within our sample, and our modeled HCN and CO emissivities are consistent with the results of observational studies of nearby galaxies and clouds in the Milky Way. CO emission shows a wide range of optical depths across different environments, ranging from optically thick in normal galaxies to moderately optically thin in more extreme systems. HCN appears only moderately optically thick and shows significant subthermal excitation in both normal and extreme galaxies. We find an anticorrelation between HCN/CO and fgrav, which implies that the HCN/CO ratio is not a reliable tracer of fgrav. Instead, this ratio appears to best track gas at moderate densities (n > 103.5 cm−3), which is below the typically assumed dense gas threshold of n > 104.5 cm−3. We also find that variations in CO emissivity depend strongly on optical depth, which is a product of variations in the dynamics of the cloud gas. HCN emissivity is more strongly dependent on excitation, as opposed to optical depth, and thus does not necessarily track variations in CO emissivity. We further conclude that a single line ratio, such as HCN/CO, will not consistently track the fraction of gravitationally bound, star-forming gas if the critical density for star formation varies in molecular clouds. This work highlights important uncertainties that need to be considered when observationally applying an HCN conversion factor in order to estimate the dense (i.e., n > 104.5 cm−3) gas content in nearby galaxies.
Detectability of biosignatures in warm, water-rich atmospheres
Authors: Taysum B. , van Zelst I. , Grenfell J. L. , Schreier F. , Cabrera J. , Rauer H.
Published: November 2024

Context. Warm rocky exoplanets within the habitable zone of Sun-like stars are favoured targets for current and future missions. Theory indicates these planets could be wet at formation and remain habitable long enough for life to develop. However, it is unclear to what extent an early ocean on such worlds could influence the response of potential biosignatures.

Aims. In this work we test the climate-chemistry response, maintenance, and detectability of biosignatures in warm, water-rich atmospheres with Earth biomass fluxes within the framework of the planned LIFE mission.

Methods. We used the coupled climate-chemistry column model 1D-TERRA to simulate the composition of planetary atmospheres at different distances from the Sun, assuming Earth’s planetary parameters and evolution. We increased the incoming instellation by up to 50% in steps of 10%, corresponding to orbits of 1.00 to 0.82 AU. Simulations were performed with and without modern Earth’s biomass fluxes at the surface. Theoretical emission spectra of all simulations were produced using the GARLIC radiative transfer model. LIFEsim was then used to add noise to and simulate observations of these spectra to assess how biotic and abiotic atmospheres of Earth-like planets can be distinguished.

Results. Increasing instellation leads to surface water vapour pressures rising from 0.01 bar (1.31%, S = 1.0) to 0.61 bar (34.72%, S = 1.5). In the biotic scenarios, the ozone layer survives because hydrogen oxide reactions with nitrogen oxides prevent the net ozone chemical sink from increasing. Methane is strongly reduced for instellations that are 20% higher than that of the Earth due to the increased hydrogen oxide abundances and UV fluxes. Synthetic observations with LIFEsim, assuming a 2.0 m aperture and resolving power of a R = 50, show that ozone signatures at 9.6 µm reliably point to Earth-like biosphere surface fluxes of O2 only for systems within 10 parsecs. The differences in atmospheric temperature structures due to differing H2O profiles also enable observations at 15.0 µm to reliably identify planets with a CH4 surface flux equal to that of Earth’s biosphere. Increasing the aperture to 3.5 m and increasing instrument throughput to 15% increases this range to 22.5 pc.
Science-management Partnerships as Catalysts for Governance Reform of National Parks in China
Authors: Huang Baorong , Zhang Zhi
Published: November 2024

Protected areas have long been considered a cornerstone of biodiversity conservation by policy-makers and the conservation community. Yet, despite ongoing efforts, many countries, including China, continue to face persistent challenges in effectively managing these areas. Here we examine how science-management partnerships, particularly those headed by Chinese Academy of Sciences (CAS), have catalyzed governance reforms of protected areas in China. The integration of scientific research with policy action has enabled the establishment of a unified national park system, mitigating management inefficiencies and enhancing ecosystem resilience. We propose strategies for CAS to consolidate its leadership in this domain. These partnerships might offer global insights into evidence-based protected area management.
BIG to CNCB: An Exploratory Journey from Genomics to Bioinformation
Authors: Yang Yungui , Xue Yongbiao , Wu Zhongyi , Yang Huanming
Published: November 2024

The Beijing Institute of Genomics (BIG) of the Chinese Academy of Sciences, as the leading Institute in Genomics, has walked through 20 year’s journey since being founded in November 2003. From participating in the Human Genome Project (HGP) in completing the “1% task” to independently accomplishing the super-hybrid rice genome and other several national and international genome projects, BIG has made tremendous contributions in genomics research and development in China. In 2024, bearing great ambition and responsibility, BIG is transformed to the China National Center for Bioinformation (CNCB), aiming to become a global hub in bioinformatics big data services, innovation, and entrepreneurship. With the completion of its new infrastructure in 2027, CNCB is looking into a brighter future.
Borosilicate glass with low dielectric loss and low permittivity for 5G/6G electronic packaging applications
Authors: Rodriguez-Cano Rocio , Clark Nicholas L. , Mauro John C. , Lanagan Michael T.
Published: November 2024

A phase-separated borosilicate glass, with a relative permittivity ranging from 3 to 3.5 and a loss tangent as low as 5.6 × 10−4, is presented for packaging applications for the next generation of mobile communications. Ionic polarizability for each borosilicate composition was calculated from the Clausius–Mossotti relationship for both the vitreous and crystalline structures, and the polarizability difference between the two is proportional to the dielectric loss. Small amounts of alkali modifier were added to improve the glass processability, and the loss tangent increased to the 1–7 × 10−3 range. The resulting glass is phase-separated, which has no impact in the millimeter-wave spectrum, as the wavelengths are considerably greater than the length scale of each immiscible phase.
Lithium battery SOC estimation based on improved sparrow search algorithm and backpropagation neural network
Authors: Zhang Yingying , Wang Ruilin , Shen Yueteng , Zhao Yu , Chen Zhiwei
Published: November 2024

Accurate state-of-charge (SOC) estimation is crucial for optimal battery management. This paper proposes a novel method, the Improved Sparrow Search Algorithm-Backpropagation (ISSA-BP) neural network, to address the issue of low estimation accuracy encountered with a single BP neural network. ISSA is used to optimize the initial weights and thresholds of the BP neural network, effectively overcoming its tendency to get stuck in local minima. Compared to the single BP neural network, ISSA-BP demonstrates significantly improved accuracy under two conditions (DST and BJDST), with reductions in root mean square error by 64.0% and 50.9% and mean absolute error by 69.8% and 51.1%, respectively. These results highlight the superior robustness and accuracy of the ISSA-BP algorithm for SOC estimation in lithium batteries.
Investigation of liquid sloshing characteristics in tanks using an OpenFOAM solver with arbitrary excitation
Authors: Li Linmin , Shen Bohan , Zhu Zuchao , Ren Qile , Zhang Junhao
Published: November 2024

A multiphase flow solver with mesh motion is typically used for simulations of liquid sloshing in containers, such as those in spacecraft, aircraft, and ships. The mode of the mesh motion should be predefined by functions, which is difficult for a sustained and arbitrary motion. In the present work, a general solver without mesh motion for liquid sloshing in tanks is proposed, based on the interFoam solver in OpenFOAM, by tracking the free surface using the volume of fluid method. An arbitrary excitation loading algorithm is implemented for automatically loading the three-dimensional arbitrary acceleration data. Moreover, the energy equation with phase change is also newly implemented in this solver so that the heat and mass transfer can be evaluated for cryogenic fuels during sloshing. In this way, arbitrary external excitations can be directly imported for any arbitrary sloshing case, and the characteristics of liquid sloshing and oscillation forces can be directly simulated without mesh motion. The solver is validated using different cases, and the influence of sloshing on the mass transfer rate and the effect of the baffle on the liquid sloshing characteristics are investigated. The results indicate that the solver can be easily applied to engineering problems involving liquid sloshing.
Silica conversion of polysilazanes by low-temperature plasma jet generated from Ar and water-vapor mixed gas
Authors: Sakaike Kohei , Higashi Seiichiro
Published: November 2024

Perhydropolysilazane (PHPS), which contains no organic catalyst, chemically reacts with H2O in the atmosphere by heating it at 450 °C for more than 1 h to turn it into a SiO2 film. If silica conversion can be achieved at temperatures below 100 °C, which plastics can withstand, it may be applicable to a wide range of applications, such as flexible electronics. Here, we report a technique for forming SiO2 films with leakage current characteristics very close to those of thermally oxidized (THOX) films that works at a very low temperature of 52 °C with high speed. Using a 9-kV, 30-kHz power supply, a low-temperature plasma jet containing a gas mixture of Ar and water vapor irradiated an 8 nm thick PHPS thin film, inducing silica conversion at a maximum substrate temperature of 52 °C. The current density-electric field strength (J-E) characteristics of metal oxide semiconductor capacitors fabricated with this SiO2 film showed characteristics very close to those of THOX films. In addition, the mechanism of silica conversion of PHPS through low-temperature plasma jet irradiation using this gas mixture was clarified in real-time FT-IR measurements.
Influence of plasma density gradient on the tearing mode with the poloidal shear flow
Authors: Ming Yue , Wang Wenjia
Published: November 2024

The influence of the plasma density gradient on the m/n = 2/1 and m/n = 4/1 (m is the poloidal mode number and n is the toroidal mode number) tearing mode instability with poloidal flow and flow shear is investigated. Using the analytical solution that we obtained in a previous work and mainly focused on the factors of plasma density and poloidal shear flow, we found that the plasma density has a stabilizing effect on the classical tearing mode, and the poloidal equilibrium flow can intensify this beneficial effect. The density gradient was detrimental to the stability of the tearing mode. The effects of both density and density gradient are slight, but the effect of poloidal flow on the plasma density is significant. Considering that the plasma density changes with the poloidal flow, the values of the tearing mode stability index ∆′ clearly change. Our investigation also found that compared with the negative flow shear, the positive flow shear is beneficial to the stability of the tearing mode, and a larger poloidal flow shear has a better stabilizing effect on the classical tearing mode.
Exploration of bismuth based perovskite materials for organic dyes removal from waste water
Authors: Mohsin Muhammad Ali , Younis Jihad , Jabeen Nawishta , Mehmood Khalid , Elnaggar Ashraf Y. , Hessien Mahmoud M.
Published: November 2024

The scourge of water pollution due to organic matter is a well-known fact. In order to address this issue, we employed a highly facile method of solid state reaction for the synthesis of bismuth potassium titanate, Bi0.5K0.5TiO3 (BKT) photocatalyst. Furthermore, the bandgap tailoring of the BKT is performed by photo-reduction of Ag onto the BKT, which results in the formation of hetero-structure junctions at the surface of the BKT. The as-prepared BKT and BKT-Ag photocatalysts are systematically characterized by x-ray diffraction, scanning electron microscopy, and high resolution transmission electron spectroscopy. Furthermore, the photocatalyst activity of the BKT and BKT-Ag was analyzed against the target organic pollutants by using UV–Vis spectroscopy. Three organic dyes such as methylene blue, eriochrome Black T, and methylene orange (MO) were used as target organic pollutants. The anchoring of Ag for the formation of hetero-structure junctions at the surface of BKT rendered it to be an ideal photo-catalyst with a bandgap reduction from 3.37 to 2.08 eV. Therefore, lowering the bandgap resulted in enhanced photocatalytic activity of the BKT-Ag. Among the three target dyes, BKT-Ag showed remarkable photo-degradation of MO and Erb T by degrading ≥90% of MO and Erb T in 120 min at neutral pH values. It is believed that BKT based photocatalysts can provide a unique platform for the removal of organic pollutants from wastewater.
Exploring the nonlinear behavior of solitary wave structure to the integrable Kairat-X equation
Authors: Alammari Maha , Iqbal Mujahid , Faridi Waqas Ali , Murad Muhammad Amin S. , Algethamie Reem , Alomari Faizah A. H. , Alsubaie Abdullah S. , Seadawy Aly R. , Yaro David
Published: November 2024

This study presented various types of soliton solutions for the nonlinear integrable Kairat-X equation by utilizing the improved F-expansion technique with symbolic computational software Mathematica. Explored results for the nonlinear integrable Kairat-X equation are interesting, novel, and more general with different physical structures of solitary waves and solitons, such as kink wave, mixed dark–bright, peakon, anti-kink wave, bright, anti-kink dark, periodic, and dark solitons. With numerical simulations, the secured soliton solutions visualized in two-dimensional, three-dimensional, and contour graphs represent the physical phenomena of the demonstrated results. The explored soliton solutions will be helpful to comprehend interesting physical structures in fiber optics, nonlinear optics, ferromagnetic dynamics, and many other scientific fields. The extracted soliton structure sheds light that the enhanced technique is effective, powerful, concise, and reliable. We can also investigate the soliton results of other nonlinear integrable partial and fractional equations.
Dynamic multilayered control of m
6
A RNA demethylase activity
Authors: Jaafar Carine , Aguiar Ricardo C. T.
Published: November 2024

Similar to DNA and histone, RNA can also be methylated. In its most common form, a N6-methyladenosine (m
6
A) chemical modification is introduced into nascent messenger ribonucleic acid (mRNA) by a specialized methyltransferase complex and removed by the RNA demethylases, Fat mass and obesity-associated (FTO), and ALKBH5. The fate of m
6
A-marked mRNA is uniquely diverse, ranging from degradation to stabilization/translation, which has been suggested to be largely dependent on its interaction with the family of YT521-B homology (YTH) domain-containing proteins. Here, we highlight a series of control levers that impinge on the RNA demethylases. We present evidence to indicate that intermediary metabolism and various posttranslation modifications modulate the activity, stability, and the subcellular localization of FTO and ALKBH5, further dispelling the notion that m
6
A methylation is not a dynamic process. We also discuss how examination of these underappreciated regulatory nodes adds a more nuanced view of the role of FTO and ALKBH5 and should guide their study in cancer and nonmalignant conditions alike.
Young children distinguish the impossible from the merely improbable
Authors: Stahl Aimee E. , Feigenson Lisa
Published: November 2024

From infancy, children show heightened interest in events that are impossible or improbable, relative to likely events. Do young children represent impossible and improbable events as points on a continuum of possibility, or do they instead treat them as categorically distinct? Here, we compared 2- and 3-y-old children’s learning (N = 335) following nearly identical events that were equi-probable, improbable, or impossible. We found that children learned significantly better following impossible than possible events, no matter how unlikely. We conclude that young children distinguish between the impossible and the merely improbable.
Definition of phosphatidylinositol 4,5-bisphosphate distribution by freeze-fracture replica labeling
Authors: Tsuji Takuma , Hasegawa Junya , Sasaki Takehiko , Fujimoto Toyoshi
Published: November 2024

Phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] is a phospholipid essential for plasma membrane functions, but its two-dimensional distribution is not clear. Here, we compared the result of sodium dodecyl sulfate–treated freeze-fracture replica labeling (SDS-FRL) of quick-frozen cells with the actual PtdIns(4,5)P2 content and the results obtained by fluorescence biosensor and by labeling of chemically-fixed membranes. In yeast, enrichment of PtdIns(4,5)P2 in the membrane compartment of Can1 (MCC)/eisosome, especially in the curved MCC/eisosome, was evident by SDS-FRL, but not by fluorescence biosensor, GFP-PLC1δ-PH. PtdIns(4,5)P2 remaining after acute ATP depletion and in the stationary phase, 30.0% and 56.6% of the control level, respectively, was not detectable by fluorescence biosensor, whereas the label intensity by SDS-FRL reflected the PtdIns(4,5)P2 amount. In PC12 cells, PtdIns(4,5)P2 was observed in a punctate pattern in the formaldehyde-fixed plasma membrane, whereas it was distributed randomly by SDS-FRL and showed clustering after formaldehyde fixation. The results indicate that the distribution of PtdIns(4,5)P2 can be defined most reliably by SDS-FRL of quick-frozen cells.
Evolution laws of charge mobility of transformer oil and pressboard material with temperature and electric field strength
Authors: Gao Chunjia , Gao Jie , Shi Haozhi , Zhao Xiaolin , Wang Ke , Zhang Shuqi , Qi Bo , Li Chengrong
Published: November 2024

Charge mobility, a pivotal parameter in the space charge analysis model for oil-pressboard insulation of converter transformer under DC electric fields, predominantly relies on theoretical or empirical data. The prevalent omission of empirical, measurement-based evaluations, combined with the neglect of temperature and electric field intensity effects, introduces uncertainties in the calculation of electric field and charge dynamics. Grounded on the principles of the electroacoustic pulse technique for space charge measurements, our investigation established a temperature-controlled platform to determine the charge-charge mobility in oil and pressboard insulation mediums. Utilizing diverse oil-pressboard insulation systems, this study identified the temporal patterns of both positive and negative charge mobilities and unravelled the mechanisms modulated by temperature and electric field intensity: (1) with increasing temperatures (from 20 °C to 80 °C) and intensifying electric field strengths (from 5kV mm−1 to 25kV mm−1), the charge mobility within transformer oil and pressboard exhibits a rising trend. Notably, temperature variations exert the most significant influence, yielding amplifications up to 24.8 times. (2) The intrinsic properties of different transformer oils and oil-impregnated pressboards result in pronounced differences in their charge transport behaviors. Specifically, naphthenic-based oil demonstrates enhanced charge mobility relative to its paraffin-based counterpart. In contrast, transformer oils with higher kinematic viscosities exhibit diminished charge mobility compared to those with lower viscosities. (3) A linear relationship is observed between the oil absorption rate and electrical conductivity, aligning closely with the insulating pressboard’s charge mobility. The evaluation of electric field and interface charge dynamics in oil-pressboard insulation under both DC and polarity-reversed conditions revealed that the electric field decay in naphthenic-based oil is more rapid than in paraffin-based oils. Moreover, both the magnitude and rate of interface charge accumulation in naphthenic-based oils exceed those in paraffin-based variants, further validating the accuracy of our charge mobility measurements and ensuing analysis.
Charge-driven first-order magnetic transition in NiPS3
Authors: Hwang Junik , Park Seonghoon , Hyun Kim Beom , Kim Junghyun , Park Je-Geun , Baek Seung-Ho
Published: November 2024

Cross-coupling among the fundamental degrees of freedom in solids has been a long-standing problem in condensed matter physics. Despite its progress using predominantly three-dimensional materials, how the same physics plays out for two-dimensional materials is unknown. Here, we show that using 31P nuclear magnetic resonance (NMR), the van der Waals antiferromagnet NiPS3 undergoes a first-order magnetic phase transition due to the strong charge-spin coupling in a honeycomb lattice. Our 31P NMR spectrum near the Néel ordering temperature

T
N

=
155

 K exhibits the coexistence of paramagnetic and antiferromagnetic phases within a finite temperature range. Furthermore, we observed a discontinuity in the order parameter at

T
N

and the complete absence of critical behavior of spin fluctuations above

T
N

, decisively establishing the first-order nature of the magnetic transition. We propose that a charge stripe instability arising from a Zhang-Rice triplet ground state triggers the first-order magnetic transition.
A hydraulic motor fault diagnosis method based on weighted multi-channel information fusion
Authors: Li Tao , Qiao Zijian , Kumar Anil , Xie Chongyang , Zhang Chenglong , Lai Zhihui
Published: November 2024

In response to the limitations of the existing single-sensor hydraulic motor fault diagnosis model, which includes significant fluctuations in fault identification accuracy, low data utilization, poor reliability, and insufficient generalization ability under variable working conditions, a novel hydraulic motor fault diagnosis method based on weighted fusion of multi-channel data and migration learning is proposed. Firstly, in order to fully extract the fault information in the multi-channel data set of the hydraulic motor, a multi-channel fusion method based on information entropy weighting is proposed. The information entropy method is employed to calculate the fusion weight of each channel of data, and the sampled data of each channel is weighted and fused. Subsequently, the fusion data from the source domain is employed to pre-train the deep transfer model, with the model parameters obtained from this pre-training serving as the initialization parameters for the target domain model. Further, the parameters of the target domain model’s feature extractor are fixed, and the parameters of its classifier are fine-tuned using the target domain’s fusion data. The distance between the source and target domains is reduced by incorporating an attention mechanism and constructing a loss function. The migration from the source domain to the target domain is achieved, which enables the classifier to adapt to the novel target sample recognition task. Ultimately, the experimental results of hydraulic motor migration diagnosis under variable operating conditions demonstrate that the proposed method is efficacious for hydraulic motor fault diagnosis. In comparison to conventional models such as CNN, LSTM and ResNet, the proposed method exhibits superior migration diagnosis accuracy and strong generalization and robustness under variable operating conditions.
How Accurate are Transient Spectral Classification Tools?— A Study Using 4646 SEDMachine Spectra
Authors: Kim Young-Lo , Hook Isobel , Milligan Andrew , Galbany Lluís , Sollerman Jesper , Burgaz Umut , Dimitriadis Georgios , Fremling Christoffer , Johansson Joel , Müller-Bravo Tomás E. , Neill James D. , Nordin Jakob , Nugent Peter , Purdum Josiah , Qin Yu-Jing , Rosnet Philippe , Sharma Yashvi
Published: November 2024

Accurate classification of transients obtained from spectroscopic data are important to understand their nature and discover new classes of astronomical objects. For supernovae (SNe), SNID, NGSF (a Python version of SUPERFIT), and DASH are widely used in the community. Each tool provides its own metric to help determine classification, such as rlap of SNID, chi2/dof of NGSF, and Probability of DASH. However, we do not know how accurate these tools are, and they have not been tested with a large homogeneous data set. Thus, in this work, we study the accuracy of these spectral classification tools using 4646 SEDMachine spectra, which have accurate classifications obtained from the Zwicky Transient Facility Bright Transient Survey (BTS). Comparing our classifications with those from BTS, we have tested the classification accuracy in various ways. We find that NGSF has the best performance (overall Accuracy 87.6% when samples are split into SNe Ia and Non-Ia types), while SNID and DASH have similar performance with overall Accuracy of 79.3% and 76.2%, respectively. Specifically for SNe Ia, SNID can accurately classify them when rlap > 15 without contamination from other types, such as Ibc, II, SLSN, and other objects that are not SNe (Purity > 98%). For other types, determining their classification is often uncertain. We conclude that it is difficult to obtain an accurate classification from these tools alone. This results in additional human visual inspection effort being required in order to confirm the classification. To reduce this human visual inspection and to support the classification process for future large-scale surveys, this work provides supporting information, such as the accuracy of each tool as a function of its metric.
ALMA and GMRT Studies of Dust Continuum Emission and Spectral Lines Toward Oort Cloud Comet C/2022 E3 (ZTF)
Authors: Manna Arijit , Pal Sabyasachi , Sinha Sekhar , Mondal Sushanta Kumar
Published: November 2024

The atomic and molecular compounds of cometary ices serve as valuable knowledge into the chemical and physical properties of the outer solar nebula, where comets are formed. From the cometary atmospheres, the atoms and gas-phase molecules arise mainly in three ways: (i) the outgassing from the nucleus, (ii) the photochemical process, and (iii) the sublimation of icy grains from the nucleus. In this paper, we present the radio and millimeter wavelength observation results of Oort cloud non-periodic comet C/2022 E3 (ZTF) using the Giant Metrewave Radio Telescope (GMRT) band L and the Atacama Large Millimeter/submillimeter Array (ALMA) band 6. We do not detect continuum emissions and an emission line of atomic hydrogen (H I) at rest frequency 1420 MHz from this comet using the GMRT. Based on ALMA observations, we detect the dust continuum emission and rotational emission lines of methanol (CH3OH) from comet C/2022 E3 (ZTF). From the dust continuum emission, the dust production (Afρ) activity of comet ZTF is 2280 ± 50 cm. Based on LTE spectral modeling, the column density and excitation temperature of CH3OH toward C/2022 E3 (ZTF) are (4.50 ± 0.25) × 1014 cm−2 and 70 ± 3 K respectively. The integrated emission maps show that CH3OH was emitted from the coma region of the comet. The production rate of CH3OH toward C/2022 E3 (ZTF) is (7.32 ± 0.64) × 1026 molecules s−1. The fractional abundance of CH3OH with respect to H2O in the coma of the comet is 1.52%. We also compare our derived abundance of CH3OH with the existence modeled value, and we see the observed and modeled values are quite similar. We claim that CH3OH is formed via the subsequential hydrogenation of formaldehyde (H2CO) on the grain surface of comet C/2022 E3 (ZTF).
Effect of alloying elements on coexisting phases and microstructure of M174 heat-resistant aluminum alloy
Authors: Tang Jinjun , Liang Cui , Li Jiqiang
Published: November 2024

This article mainly focuses on high-power density diesel engine piston alloys, with the main component system being M174 heat-resistant aluminum alloy. On this basis, the main heat-resistant alloying elements Cu, Ni, and Fe were optimized and designed. This article is based on Thermo-Calc thermodynamic software, and comprehensively calculates and analyzes the multi-component alloy equilibrium phase diagram and Scheil non-equilibrium solidification of Al-(4-6)Cu-(1.5-3)Ni-(0.7-1.1Fe)-12.5Si-0.85Mg (mt.%) heat-resistant aluminum alloy system. Through the orthogonal experimental method of alloy composition, the phase distribution and microstructure composition of different alloy compositions are obtained. Research has found that Fe-rich phases such as Al5FeSi and Al9FeNi, as well as Ni-rich phases such as A13CuNi, A17Cu4Ni, and Al3Ni, are the main heat-resistant phases of the alloy in the temperature range of 350°C-420°C, providing important support for the high-temperature mechanical properties and creep damage resistance of piston aluminum alloy. At the same time, this article further studies the solidification history and microstructure precipitation of alloys. Fe-rich heat-resistant phases such as Al5FeSi and Al9FeNi have a higher solidification sequence. As primary and secondary phases, it is easy to generate coarse solidified structures. The organizational content is sensitive to the alloy composition. A13CuNi and A17Cu4Ni mainly precipitate in a multi-component eutectic structure, with layered and petal-shaped morphologies. The research results of this article have important theoretical significance and application value for the optimization design of high-power density piston aluminum alloy composition and the coordinated control of multi-phase structure.
Detection and characterization of hole processing defects in carbon fiber-reinforced polymer
Authors: Han Shanling , Li Xiaodong , Cui Zhen , Li Yong
Published: November 2024

The defects of carbon fiber-reinforced polymer (CFRP) during the drilling process will affect the mechanical properties and service life of the components. We investigate the detection and characterization of delamination and burr defects after drilling CFRP. The drilling test was conducted on CFRP specimens, followed by image processing software to detect and extract the resulting defects. Subsequently, a more accurate two-dimensional quantitative characterization of the extracted delamination and burr defects was performed. Finally, by comprehensively considering the quality indexes of delamination and burr defects, a comprehensive evaluation factor that can fully reflect the hole-making defects is established to provide a theoretical basis and technical support for enhancing CFRP’s hole-making quality.
Design and aerodynamic performance study of subsonic Y-shaped inlet
Authors: Yan Ziguang , Zhao Zhifang , Li Linjie , Wu Mengwei
Published: November 2024

A Y-shaped inlet with a quadrate import was designed by the super-ellipse method in this paper, and according to the variation pattern of the cross-section of the inlet, the variation pattern of the short and long axis of the super-ellipse was deduced. For many different flight situations, the numerical simulations of the Y-shaped inlet were made. The result shows (1) If 0.2≤Ma≤0.8, the total pressure recovery coefficient exceeds 0.96, and the total pressure distortion coefficient is close to 0.1, meeting the criterion of the design; (2) When Ma=0.8, for many different attack angle α=-4°∼22°, the total pressure recovery coefficient is close to 0.97, reaching the level of practical application, and it has little impact on total pressure recovery coefficient and the distortion coefficient. (3) These results demonstrate high total pressure recovery and low distortion coefficients across various flight conditions, indicating its potential for practical applications and future inlet designs.
Design and optimization of the exhaust system for an aviation piston engine
Authors: Chen Jinqian , Zhang Chen , Chen Wei , Zhang Zhecheng
Published: November 2024

To further enhance the performance of an aviation piston engine, an engine performance simulation analysis model was constructed by using GT-Power software to design improvements to its exhaust system. The impacts of different exhaust system schemes on the exhaust process, the in-cylinder combustion, and the heat release process at a cruising speed of 5500 RPM were analyzed. Based on the results, under cruising speed conditions, a new exhaust system was designed for the engine by referring to the structural form of a resonant exhaust system. The D-optimal Latin hypercube sampling method was used to obtain sample data for the experimental design of the structural parameters of the designed exhaust system. The response surface approximation models characterizing power and fuel consumption rate were established by using the least squares method. The significance of the impact of each structural parameter on engine performance was analyzed through a multifactor analysis of variance. The key structural parameters of the designed exhaust system were then subjected to multi-objective optimization. The results indicate that at 5500 RPM, the designed exhaust system can increase engine power by 2.88%; after optimization, engine power can be further increased by 3.15%, and the fuel consumption rate is reduced by 4.07%.
Effect of tempering process on the structure and properties of M51/X32 bimetal band saw blade
Authors: Zhao Gusiyang , Liu Yan , Song Zhuo , Li Guimao , Fu Bo , Xia Changsheng , Ning Qu
Published: November 2024

The mechanical properties of band saw have a great influence on the cutting life. In this paper, through the systematic study of M51/X32 bimetallic band saw blade with different tempering temperatures and times, the metallography of the bimetallic band saw blade under different heat treatment conditions was analyzed. The mechanical properties of the bimetallic band saw blade under different conditions were tested. The results showed that the carbide in the metallography of the tooth tip was uniform and tended to be spherical when tempering at 600°C for five times. The mechanical properties such as hardness, tensile strength, and fatigue properties are well matched, which can extend the service life of bimetallic band saw blades and ensure the cutting quality.
Reaction chamber design for an organic molecular layer deposition instrument
Authors: Zhu Shuai , Li Pengfei , Yang Dada , Hou Yang , Sheng Qiaorui
Published: November 2024

In the molecular layer deposition (MLD) process, the reaction chamber plays a crucial role as the deposition carrier. The geometry of the reaction chamber directly affects the deposition processes of delivery, heating of reactive gases, and purging of excessive molecules. In this study, we designed an MLD instrument for the preparation of pure organic polymer layered coatings and investigated key structural parameters of its reaction chamber. By the Computational Fluid Dynamics (CFD) method, precursor delivery, nitrogen purge, vacuuming, and oil bath heating in the deposition process were modeled. The flow field distribution under different inlet and outlet heights and the temperature field distribution under different axial heights of the chamber were analyzed, and the most suitable parameters were thus determined. The results showed that when the heights of precursor inlet, nitrogen inlet, and vacuum pumping outlet were selected as 50 mm, 45 mm, and 50 mm, respectively, the chamber could serve better deposition and purge efficiency. When the axial height of the chamber is 185 mm, both the chamber and the fluoro rubber sealing ring meet the temperature requirements.
Study on the mechanical properties and microstructures of Al-Cu-Mg alloy thick plates obtained by different hot rolling processes
Authors: Zhu Kai , Liu Qilong , Fu Jinlai , Lv Jing , Yan Lizhen , Li Yanan , Li Xiwu
Published: November 2024

In the research, the microstructures of large-scale 2324 aluminum alloy thick plates obtained through two different hot rolling processes are investigated by using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and Electron Backscatter Diffraction (EBSD). Additionally, the tensile properties of the plates are evaluated at room temperature. The results indicate that the thick plates produced by Process A exhibit higher tensile and yield strengths along the L (longitudinal) and LT (long transverse) directions. The higher proportion of deformed microstructures is an important factor contributing to their enhanced tensile and yield strengths. Meanwhile, the different rolling processes have minimal impact on the kind and distribution of the second phase in the hot-rolled thick plates, with the second phase primarily consisting of Al2Cu and Al2CuMg phases, which are distributed in a streamlined way along the rolling direction of the thick plates. The microstructures of the hot-rolled thick plates obtained from both hot-rolling processes are dominated by deformed structures. The thick plates produced by Process B have relatively smaller grain sizes and a higher degree of fragmentation, making their microstructure more susceptible to recrystallization transformation during subsequent solution heat treatment.
Simulation-based analysis of welding process parameters for TC4ELI titanium alloy thick-walled cylinders
Authors: Gao Guanghui , Cheng Xiaowei , Gao Yue
Published: November 2024

In this paper, ABAQUS is used to numerically simulate the residual stresses during welding of titanium alloy thick-walled cylinders. A detailed simulation analysis of the stress field during the welding process is performed by establishing an accurate finite element model, defining the thermal physical properties, boundary conditions, and heat source model, and using the indirect heat-force coupling method. The results of the study show that the distribution of the weld stress field has an important influence on weld quality, material properties, and structural strength. The movement of the welding heat source results in a dynamic change in the stress field, which gives rise to a significant stress concentration at and in the vicinity of the welding heat source.
Study on tensile damage evolution of Ti6Al4V alloy based on DIC technique
Authors: Mao Dexin , Li Lei , Li Xiaodong , Sun Zhankun , Zhang Li , Liu Qiao
Published: November 2024

Both optical microscopy (OM) and scanning electron microscopy (SEM) were used to analyze the microstructure of the Ti6Al4V alloy and evaluate its tensile damage behavior. Using Lemaitre’s definition of damage, the variation rule of damage during the reduction of elastic modulus was obtained. Combining the digital image correlation (DIC) analysis approach allowed for an experimental investigation of the alloys’ tensile mechanical characteristics. The strains at 500 independent points were extracted using VIC-2D software. The damage factor of the whole strain field was established by equations and 3D graphics, and the damage evolution process was visualized and analyzed. The results show that the Ti6Al4V alloy has good plasticity, and its fracture mode is a ductile fracture. The sample’s modulus of elasticity falls, and the extent of damage increases as the stretching continues. The sample undergoes a localized violent deformation during the tensile process, as opposed to a homogenous deformation state. The harm progressively concentrates and increases at an increased rate.
The integrated performance of adaptive temperature control and temperature measurement of PTC materials with high thermal cycle repeatability
Authors: Yang Yinfa , Hao Jianmin , Chen Hua , Cheng Wenlong
Published: November 2024

As the temperature increases, the resistance of the positive temperature coefficient (PTC) material becomes larger. Using this material can reduce the complexity of the temperature control system. In this paper, a new PTC material is developed by means of melt blending, which still has operable PTC characteristics after 60 high and low temperature cycles. The data points collected in multiple thermal cycles were fitted to obtain the relationship between the sample’s temperature and resistance. In addition, the integrated performance of adaptive temperature control and temperature measurement of PTC materials is proposed for the first time. Based on the prepared samples, the temperature control characteristics of PTC materials on the controlled object under different environmental conditions are studied experimentally, and the temperature value converted from the resistance value is compared with the temperature value measured by the platinum resistance. The results show that the prepared sample has good temperature control performance, and the material has an operable temperature measurement function in the PTC effect range.
Study on the influence of trace elements H on the properties of A356 aluminum alloy
Authors: Lv Jianjun , Zhang Jiang , Hong Xiaolu , Zhou Peixu , Chen Dahui , Peng Yingjiang
Published: November 2024

The vacuum melt purification refining technology can significantly reduce the content of hydrogen elements in alloy melts and prevent defects such as hydrogen-induced pinholes. This article investigates the effect of hydrogen content on the chemical composition, mechanical properties, and structural defects of A356 alloy melt by using vacuum melt purification refining technology to reduce the hydrogen content in A356 alloy melt. The experimental results show that: 1) there is basically no loss of chemical elements during the vacuum melting process; 2) The use of vacuum refining and purification control technology can control the hydrogen content inside the melt to be ≤ 0.10ml/100g; 3) The effect of H content on the metallographic structure of A356 alloy is not significant, but it has a certain improvement on the tensile strength at room temperature, but the increase is ≤ 5%.
Study on warm formability of 2219 aluminum alloy with pre-deformation
Authors: Gao Qi , Zhang Zhichao , Meng Jinlong , Fan Xiaobo
Published: November 2024

The manufacturing process of launch vehicle storage tanks requires urgent simplification, which can be improved by forming the local features after artificial aging. Therefore, a new process of warm flanging aluminum alloys with pre-deformation was proposed to meet this requirement. The mechanical properties of 2219 aluminum alloy with pre-deformation were investigated at different temperatures using thermomechanical property testing. The deformation law of warm flanging was analyzed through simulation. The flanging limit of 2219 aluminum alloy with pre-deformation was obtained through experiments. Results showed that the ductility of 2219 aluminum alloy with pre-deformation increased then decreased with the increasing temperature, a maximum strain of 0.65 was obtained at 200°C. The equivalent strain gradually rose from the corner zone to the straight wall zone during flanging. The maximum equivalent strain is located at the edge of the straight wall, which gradually decreases with the increasing flanging coefficient. A flanging coefficient of 0.60 can be obtained at 200°C without splitting or seriously thinning. These results guide the local flanging of the integral bottom of 2219 aluminum alloy.