► A 2NN MEAM potential for Li–Si alloys is developed. ► The potential is based on PSO method and ab initio calculations. ► Transition is employed to prove the robustness of the potential. ► New ...potential is capable of predicting the material properties of Li–Si alloys.
A second nearest-neighbor modified embedded atom method (2NN MEAM) interatomic potential for lithium–silicon (Li–Si) alloys is developed by using the particle swarm optimization (PSO) method in conjunction with ab initio calculations. It is shown that the new interatomic potential is capable of simulating the transition from disordered to ordered states of Li–Si crystalline structures, an indication of the stability and robustness of the interatomic potential at finite temperature. Examples are given to demonstrate that the new interatomic potential is also capable of predicting the material properties of both crystalline and amorphous Li–Si alloys, including the elastic modulus, compositional expansion, diffusivity of Li in Li–Si alloys, plastic yield strength, etc.
The self-focusing properties of the Laguerre–Gaussian beams in nonlinear plasma, characterized by significant collisional or ponderomotive nonlinearity have been explored. The second-order ...differential equation of the beam width is established from Maxwell’s equations with Wentzel–Kramers–Brillouin and paraxial like approximation. The effect of the vortex charge number, intensity parameter and plasma temperature on the self-focusing properties of the Laguerre–Gaussian beam has been investigated.
Traditional nonintelligent signal control systems are typically used in road traffic signal systems, which cannot provide optimal guidance and have low traffic efficiency during rush hour. This study ...proposes a traffic signal phase dynamic timing optimization strategy based on a time convolution network and attention mechanism to improve traffic efficiency at intersections. The corresponding optimization was performed after predicting traffic conditions with different impacts using the digital twinning technique. This method uses a time-convolution network to extract the cross-time nonlinear characteristics of traffic data at road intersections. An attention mechanism was introduced to capture the relationship between the importance distribution and duration of the historical time series to predict the traffic flow at an intersection. The interpretability and prediction accuracy of the model was effectively improved. The model was tested using traffic flow data from a signalized intersection in Shangrao, Jiangxi Province, China. The experimental results indicate that the model generated by training has a strong learning ability for the temporal characteristics of traffic flow. The model has high prediction accuracy, good optimization results, and wide application prospects in different scenarios.
Jurassic sandstones in the Xiongcun porphyry copper–gold district, southern Lhasa subterrane, Tibet, China were analysed for petrography, major oxides and trace elements, as well as detrital zircon ...U–Pb and Hf isotopes, to infer their depositional age, provenance, intensity of source-rock palaeo-weathering and depositional tectonic setting. This new information provides important evidence to constrain the tectonic evolution of the southern Lhasa subterrane during the Late Triassic – Jurassic period. The sandstones are exposed in the lower and upper sections of the Xiongcun Formation. Their average modal abundance (Q21F11L68) classifies them as lithic arenite, which is also supported by geochemical studies. The high chemical index of alteration values (77.19–85.36, mean 79.96) and chemical index of weathering values (86.19–95.59, mean 89.98) of the sandstones imply moderate to intensive weathering of the source rock. Discrimination diagrams based on modal abundance, geochemistry and certain elemental ratios indicate that felsic and intermediate igneous rocks constitute the source rocks, probably with a magmatic arc provenance. The detrital zircon ages (161–243 Ma) and εHf(t) values (+10.5 to +16.2) further constrain the sandstone provenance as subduction-related Triassic–Jurassic felsic and intermediate igneous rocks from the southern Lhasa subterrane. A tectonic discrimination method based on geochemical data of the sandstones, as well as detrital zircon ages from sandstones, reveals that the sandstones were most likely deposited in an oceanic island-arc setting. These results support the hypothesis that the tectonic background of the southern Lhasa subterrane was an oceanic island-arc setting, rather than a continental island-arc setting, during the Late Triassic – Jurassic period.
Rotation axes have been proven to be the greatest factor leading to machine tool errors, which seriously affect the machining accuracy. Therefore, it is imperative to identify the geometric errors of ...the rotation axes. This research focuses on how to identify the critical geometric errors of the rotation axes, so that the coupling effect of geometric errors which seriously affects the identification of geometric errors of the rotation axes can be examined. To achieve this goal, this paper proposes a global quantitative sensitivity analysis method based on homogeneous transformation matrix (HTM) theory and Sobol sensitivity analysis method. The size and randomness of geometric errors are taken into consideration and the specific indexing angles of the rotation axes are introduced to identify the critical geometric errors of the five-axis machine tool. Based on this analysis method, each geometric error components and the coupling effect between different error sources are evaluated under different indexing angles. The variation of the coupling effect of each error components within the traverse of the rotation axes is explored. The geometric error measurement experiment is established and the results are compared with the simulation results. The simulation results and experimental results reveal that the critical geometric errors that affect the machining accuracy and the variation of the geometric errors coupling effect, which provides useful guidance for the manufacturers and users of five-axis machine tools.
We present a coarse-grained model for molecular dynamics simulations of an epoxy system composed of epoxy phenol novolac as epoxy monomer and bisphenol-A as the cross-linking agent. The epoxy and ...hardener molecules are represented as short chains of connected beads, and cross-linking is accomplished by introducing bonds between reactive beads. The interbead potential, composed of Lennard-Jones, bond stretching, and angle bending terms, is parametrized through an optimization process based on a particle swarm optimization method to fit certain key thermomechanical properties of the material obtained from experiments and previous full atomistic simulations. The newly developed coarse-grained model is capable of predicting a number of thermomechanical properties of the epoxy system. The predictions are in very good agreement with available data in the literature. More importantly, our coarse-grained model is capable of predicting tensile failure of the epoxy system, a capability that no other conventional molecular dynamic simulation model has. Finally, our coarse-grained model can speed up the simulations by more than an order of magnitude when compared with traditional molecular dynamic simulations.
Hypoxia-mediated chemoresistance plays a crucial role in the development of ovarian cancer (OC). However, the roles of hypoxia-related genes (HRGs) in chemoresistance and prognosis prediction and ...theirs underlying mechanisms remain to be further elucidated. We intended to identify and validate classifiers of hub HRGs for chemoresistance, diagnosis, prognosis as well as immune microenvironment of OC, and to explore the function of the most crucial HRG in the development of the malignant phenotypes. The RNA expression and clinical data of HRGs were systematically evaluated in OC training group. Univariate and multivariate Cox regression analysis were applied to construct hub HRGs classifiers for prognosis and diagnosis assessment. The relationship between classifiers and chemotherapy response and underlying pathways were detected by GSEA, CellMiner and CIBERSORT algorithm, respectively. OC cells were cultured under hypoxia or transfected with HIF-1α or HIF-2α plasmids, and the transcription levels of TGFBI were assessed by quantitative PCR. TGFBI was knocked down by siRNAs in OC cells, CCK8 and in vitro migration and invasion assays were performed to examine the changes in cell proliferation, motility and metastasis. The difference in TGFBI expression was examined between cisplatin-sensitive and -resistant cells, and the effects of TGFBI interference on cell apoptosis, DNA repair and key signaling molecules of cisplatin-resistant OC cells were explored. A total of 179 candidate HRGs were extracted and enrolled into univariate and multivariate Cox regression analysis. Six hub genes (TGFBI, CDKN1B, AKAP12, GPC1, TGM2 and ANGPTL4) were selected to create a HRGs prognosis classifier and four genes (TGFBI, AKAP12, GPC1 and TGM2) were selected to construct diagnosis classifiers. The HRGs prognosis classifier could precisely distinguish OC patients into high-risk and low-risk groups and estimate their clinical outcomes. Furthermore, the high-risk group had higher percentage of Macrophages M2 and exhibited higher expression of immunecheckpoints such as PD-L2. Additionally, the diagnosis classifiers could accurately distinguish OC from normal samples. TGFBI was further verified as a specific key target and demonstrated that its high expression was closely correlated with poor prognosis and chemoresistance of OC. Hypoxia upregulated the expression level of TGFBI. The hypoxia-induced factor HIF-2α but not HIF-1α could directly bind to the promoter region of TGFBI, and facilitate its transcription level. TGFBI was upregulated in cisplatin-sensitive and resistant ovarian cancer cells in a cisplatin time-dependent manner. TGFBI interference downregulated DNA repair-related markers (p-p95/NBS1, RAD51, p-DNA-PKcs, DNA Ligase IV and Artemis), apoptosis-related marker (BCL2) and PI3K/Akt pathway-related markers (PI3K-p110 and p-Akt) in cisplatin-resistant OC cells. In summary, the HRGs prognosis risk classifier could be served as a predictor for OC prognosis and efficacy evaluation. TGFBI, upregulated by HIF-2α as an HRG, promoted OC chemoresistance through activating PI3K/Akt pathway to reduce apoptosis and enhance DNA damage repair pathway.
Gas-driven limnic eruption can happen in a lake with an aqueous gas solution that becomes supersaturated due to some reason. In this case, the exsolution of massive gases dissolved in the water could ...occur in a very short time, resulting in a disaster as happened in the Lake Nyos (Cameroon, Africa) in 1986. Using degassing pipe to artificially release the dissolved gases is a good way to minimize the risk of an eruption. In this study, a transient multi-component gas-liquid two-phase flow model of the degassing pipe used in Lake Nyos has been established and verified with the observed eruption data. The drift flux model has been used for modelling of a transient multi-component gas-liquid flow formed due to the spontaneous exsolution of gases dissolved in the water inside the degassing pipe. The governing equations for the mechanistic drift model include continuity equation for each phase, a single momentum equation for a homogeneous mixture of the fluid, constitutive equations for mass transfer rates between the phases, and the drift velocity formulas. The model considered not only CO2 but also CH4 as dissolved gases. The “chain reaction” conjecture predicted to have the degassing-point migrating downward with time during the transient degassing process is verified by using this model. The relationship between the eruption height and the CO2 concentration at the bottom of the degassing pipe has been simulated in detail. This relationship supplies people with a quick and convenient way to estimate the CO2 concentration in the lake, based on which one can evaluate the risk of lake eruption and hence to formulate or adjust the degassing plan. In addition, the effects of diameter and equivalent roughness of the degassing pipe on the eruption height has been investigated. Meanwhile, the eruption height upper-limit in different lake-depth scenarios has also been determined. Finally, the role of CH4 component in the degassing process has been analyzed. Although the influence of CH4 on eruption height can be neglected in Lake Nyos' case, CH4 as a dissolved gas plays an important role at Lake Kivu. The multi-component gas-liquid flow model developed in this study is useful to study the role of CH4 in the degassing process.
•Transient multi-component gas-liquid two-phase flow model of a degassing pipe.•‘Conjecture’ of degassing-point migrating downwards with time has been verified.•Relationship between eruption height and CO2 concentration has been determined.•Effects of pipe diameter and roughness on eruption height has been investigated.•The role of CH4 component in the vertical two-phase flow has been analyzed.
Implementing real-time carbon emissions monitoring at the enterprise level enables the detailed breakdown of carbon neutrality goals for microcosmic enterprises, which is of paramount significance in ...ensuring the precision of policy formulations. Grounded in China’s historical electricity consumption and carbon emissions data, this study utilizes the network approach and input–output methods to compute and predict direct and indirect transmission coefficients of electricity consumption and carbon emissions in each province. We establish a methodology that enables the monitoring of real-time carbon emissions of enterprises based on corporate electricity consumption data. Using the metal smelting industry in Guangxi as an example, our findings are as follows: First, in 2020, the comprehensive carbon emissions of the ferrous metal smelting industry in Guangxi reached 58.84 million tons, marking a notable increase of 42.78% compared to emissions in 2014, indicating that emissions reductions are imperative. Second, significant regional variations in emission coefficients are observed, with values ranging from 14 g CO2/KWh to 940 g CO2/KWh among provinces. Meanwhile, the trends of direct carbon emissions and indirect carbon emissions are totally different, underscoring the importance of comprehensive carbon accounting in informing policy decisions. Third, through the carbon emissions real-time monitoring of 75 metal smelting industry enterprises using electricity big data, we identified that the distribution of emissions across industries, time periods, and regions is uneven. Overall, this method can optimize carbon emission measurement techniques to a higher spatiotemporal resolution and more microscopic monitoring subjects, providing essential numerical foundations for promoting carbon emissions reduction and sustainable development.
As a kind of non-diffracting beam, optical needle is gaining increased attention for its interesting properties and various potential applications. In this paper, we theoretically investigate the ...optical trapping force and torque on a Rayleigh spheroidal particle by an optical needle. A strategy to realize a non-diffracting optical needle by focusing a radially polarized vortex (RPV) beam with a high numerical aperture (NA) lens system is introduced and a diffractive optical element (DOE) is adopted to control the field distribution of the optical needle. Based on the field expressions of the optical needle derived through the Richards and Wolf theory, the factors affecting the properties of the optical needle are examined. Within the framework of dipole approximation, the optical trapping force and torque of an optical needle on a prolate spheroid with any spatial orientation are calculated. Numerical results show that the trapping force and torque are significantly affected by the field distribution of the optical needle, as well as the ellipticity and orientation of the spheroid. The present study may provide useful insights into the dynamic behavior during an actual optical trapping.
