Grid-following voltage source converter(GFLVSC)and grid-forming voltage source converter(GFM-VSC)have different dynamic characteristics for active power-frequency andreactive power-voltage supports of the power *** p...
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Grid-following voltage source converter(GFLVSC)and grid-forming voltage source converter(GFM-VSC)have different dynamic characteristics for active power-frequency andreactive power-voltage supports of the power *** paper aims to clarify andrecognize the difference between gridfollowing(GFL)and grid-forming(GFM)frequency-voltage support more intuitively and ***,the phasor model considering circuit constraints is established based on the port circuit equations of the *** is revealed that the voltage and active power linearly correspond to the horizontal and vertical axes in the phasor space referenced to the grid voltage ***,based on topological homology,GFL and GFM controls are transformed and mapped into different *** topological similarity of the characteristic curves for GFL and GFM controls is the essential cause of their *** on the above model,it is indicated that GFL-VSC and GFM-VSC possess uniformity with regard to active powerresponse,type of coupling,and phasor *** differ in synchronization,power coupling mechanisms,dynamics,and active power-voltage operation domain in the quasi-steady *** studies are undertaken on GFL-VSC and GFM-VSC integrated into a four-machine two-area *** results verify that the dynamic uniformity anddifference of GFL-VSC and GFM-VSC are intuitively and comprehensively revealed.
The microstructural evolution of a cold-rolled and intercritical annealed medium-Mn steel(Fe-0.10C-5Mn)was investigatedduring uniaxial tensile ***-situ observations under scanning electron microscopy,transmission ele...
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The microstructural evolution of a cold-rolled and intercritical annealed medium-Mn steel(Fe-0.10C-5Mn)was investigatedduring uniaxial tensile ***-situ observations under scanning electron microscopy,transmission electron microscopy,and X-ray diffraction analysis were conducted to characterize the progressive transformation-induced plasticity process and associated fracture initiation *** findings were discussed with the local strain measurements via digital image *** results indicated that Lüders band formation in the steel was limited to 1.5%strain,which was mainly due to the early-stage martensitic phase transformation of a very small amount of the less stable large-sizedretained austenite(rA),which led to localized stress concentrations and strain hardening and furtherretardation of *** small-sizedrA exhibited high stability and progressively transformed into martensite and contributed to a stably extended Portevin-Le Chatelier *** volume fraction of rA gradually decreased from 26.8%to 8.2%prior to *** the late deformation stage,fracture initiation primarily occurred at the austenite/martensite and ferrite/martensite interfaces and the ferrite phase.
The demand for anisotropic aerogels with excellent comprehensive properties in cutting-edge fields such as aerospace is *** on the above background,a novel heterocyclic para-aramid nanofiber/reduced graphene oxide(HPA...
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The demand for anisotropic aerogels with excellent comprehensive properties in cutting-edge fields such as aerospace is *** on the above background,a novel heterocyclic para-aramid nanofiber/reduced graphene oxide(HPAN/rGO)composite aerogel was prepared by combining electrospinning and unidirectional *** anisotropic HPAN/rGO composite aerogel exhibited a honeycomb morphology in the direction perpendicular to the growth of ice crystals,and a through-well structure of directed microchannels in the direction parallel to the temperature *** varying the mass ratio of HPAN/rGO,a composite aerogel with an ultra-low density of 5.34-7.81 mg·cm^(-3) and an ultra-high porosity of 98%-99%was *** from the anisotropic structure,the radial and axial thermal conductivities of HPAN/rGO-3 composite aerogel were 29.37 and 44.35 mW·m^(-1)·K^(-1),respectively.A combination of software simulation and experiments was used to analyze the effect of anisotropic structures on the thermal insulation properties of ***,due to the intrinsic self-extinguishing properties of heterocyclic para-aramid and the protection of the graphene carbon layer,the composite aerogel also exhibits excellent flame retardancy properties,and its total heat release rate(THr)was only 5.8 kJ·g^(-1),which is far superior to many reported ***,ultralight anisotropic HPAN/rGO composite aerogels with excellent high-temperature thermal insulation and flame retardancy properties have broad application prospects in complex environments such as aerospace.
The expandable graphite(EG)modified TiO_(2) nanocomposites were prepared by the high shearmethod using the TiO_(2) nanoparticles(NPs)and EG as precursors,in which the amount of EG doped in TiO_(2) was 10 wt.%.Followed...
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The expandable graphite(EG)modified TiO_(2) nanocomposites were prepared by the high shearmethod using the TiO_(2) nanoparticles(NPs)and EG as precursors,in which the amount of EG doped in TiO_(2) was 10 wt.%.Followed by the impregnation method,adjusting the pH of the solution to 10,and using the electrostatic adsorption to achieve spatial confinement,the Pt elementswere mainly distributed on the exposed TiO_(2),thus generating the Pt/10EG-TiO_(2)-10 *** best CO oxidation activity with the excellent resistance to H_(2)O and SO_(2) was obtained over the Pt/10EG-TiO_(2)-10 catalyst:CO conversion after 36 hr of the reaction was ca.85%under the harsh condition of 10 vol.%H_(2)O and 100 ppm SO_(2) at a high gaseous hourly space velocity(GHSV)of 400,000 hr−*** properties of the catalystswere characterized by various *** results showed that the electrostatic adsorption,which riveted the Pt elements mainly on the exposed TiO_(2) of the support surface,reduced the dispersion of Pt NPs on EG and achieved the effective dispersion of Pt NPs,hence significantly improving CO oxidation activity over the Pt/10EG-TiO_(2)-10 *** 10 wt.%EG doped in TiO_(2) caused the TiO_(2) support to form a more hydrophobic surface,which reduced the adsorption of H_(2)O and SO_(2) on the catalyst,greatly inhibiteddeposition of the TiOSO_(4) and formation of the PtSO4 species as well as suppressed the oxidation of SO_(2),thus resulting in an improvement in the resistance to H_(2)O and SO_(2) of the Pt/10EG-TiO_(2)-10 catalyst.
Estimating the 3doF rotation from a single rGB image is an important yet challenging problem. As a popular approach, probabilistic rotation modeling additionally carries prediction uncertainty information, compared to...
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Estimating the 3doF rotation from a single rGB image is an important yet challenging problem. As a popular approach, probabilistic rotation modeling additionally carries prediction uncertainty information, compared to single-prediction rotation regression. For modeling probabilistic distribution over SO(3), it is natural to use Gaussian-like Bingham distribution and matrix Fisher, however they are shown to be sensitive to outlier predictions, e.g., 180(degrees) error and thus are unlikely to converge with optimal performance. In this paper, we draw inspiration from multivariate Laplace distribution and propose a novel rotation Laplace distribution on SO(3). Ourrotation Laplace distribution is robust to the disturbance of outliers and enforces much gradient to the low-errorregion that it can improve. In addition, we show that our method also exhibits robustness to small noises and thus tolerates imperfect annotations. With this benefit, we demonstrate its advantages in semi-supervisedrotation regression, where the pseudo labels are noisy. To further capture the multi-modal rotation solution space for symmetric objects, we extend ourdistribution to rotation Laplace mixture model anddemonstrate its effectiveness. Our extensive experiments show that our proposeddistribution and the mixture model achieve State-of-the-Art performance in all the rotation regression experiments over both probabilistic and non-probabilistic baselines.
Tendon-driven robots have distinct advantages in high-dynamic performance motion and high-degree-of-freedom ***,these robots face challenges related to control complexity,intricate tendon drive paths,and tendon *** th...
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Tendon-driven robots have distinct advantages in high-dynamic performance motion and high-degree-of-freedom ***,these robots face challenges related to control complexity,intricate tendon drive paths,and tendon *** this study,the authors present a novel modular tendon-driven actuatordesign that integrates a series elastic *** actuator incorporates a unique magnetic position sensing technology that enables observation of the length and tension of the tendon and features an exceptionally compact *** modular architecture of the tendon-driven actuator addresses the complexity of tendon drive paths,while the tension observation functionality mitigates slackness *** design and modeling of the actuator are described in this paper,and a series of tests are conducted to validate the simulation model and to test the performance of the proposed *** model can be used for training robot control neural networks based on simulation,thereby overcoming the challenges associated with controlling tendon-driven robots.
We propose a mixed precision Jacobi algorithm for computing the singular value decomposition (SVd) of a dense matrix. After appropriate preconditioning, the proposed algorithm computes the SVd in a lower precision as ...
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We propose a mixed precision Jacobi algorithm for computing the singular value decomposition (SVd) of a dense matrix. After appropriate preconditioning, the proposed algorithm computes the SVd in a lower precision as an initial guess and then performs one-sided Jacobi rotations in the working precision as iterative refinement. By carefully transforming a lower precision solution to a higher precision one, our algorithm achieves about 2x speedup on the x86-64 architecture compared to the usual one-sided Jacobi SVd algorithm in LAPACK, without sacrificing the accuracy. CCS Concepts: centerdot Mathematics of computing -> Computations on matrices
Accurate monitoring of atmospheric delta C-13 isotope is critical for quantifying anthropogenic carbon emissions and ecosystem responses within global carbon cycle research. This study used off-axis integrated cavity ...
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Accurate monitoring of atmospheric delta C-13 isotope is critical for quantifying anthropogenic carbon emissions and ecosystem responses within global carbon cycle research. This study used off-axis integrated cavity output spectroscopy (OA-ICOS) combined with distributed feedback (dFB) laser and achieved an effective absorption path length of approximately 22 km, for the simultaneous detection of carbon dioxide and its isotope (delta C-13) under atmospheric background conditions. Laboratory validation demonstrateddetection limits of 104.5 ppb, 3.3 ppb, and 0.72 parts per thousand for (CO2)-C-12, (CO2)-C-13, anddelta C-13, respectively, with a 2000 s integration time, alongside linear calibration r-2 > 0.999. While Kalman filtering reduced concentration variability by 73.5%-74.7% and improveddelta C-13 precision 4.6 times. The sensor's capability to quantify isotopic ratios and molecular concentrations in real-time addresses critical gaps in atmospheric background monitoring, offering a robust tool for climate research and carbon source-sink analysis, expanding the applicability of laser spectroscopy in environmental sensing.
Botryosphaeria laricina(larch shoot blight)was first identified in 1973 in Jilin Province,*** disease spreadrapidly and caused considerable damage because its pathogenesis was unknown at the time and there were no ef...
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Botryosphaeria laricina(larch shoot blight)was first identified in 1973 in Jilin Province,*** disease spreadrapidly and caused considerable damage because its pathogenesis was unknown at the time and there were no effective controls or quarantine *** present,it shows a spreading trend,but most research can only conduct physiological analyses within a relatively short period,combining individual influencing ***,methods such as neural network models,ensemble learning algorithms,and Markov models are used in pest anddisease prediction and ***,there may be fitting issues or inherent limitations associated with these *** study obtained *** data at the county level from 2003 to *** dataset was augmented using the SMOTE algorithm,and then algorithms such as XGBoost were used to select the significant features from a combined set of 12 features.A new stacking fusion model has been proposed to predict the status of *** model is based on random forest,gradient boosteddecision tree,CatBoost and logistic regression *** accuracy,recall,specificity,precision,F_(1) value and AUC of the model reached 90.9%,91.6%,90.4%,88.8%,90.2%and 96.2%.The results provide evidence of the strong performance and stability of the *** is mainly found in the northeast and this study indicates that it is spreading *** means should be used promptly to prevent furtherdamage and spread.
degradation of materials is one of the most critical aging mechanisms affecting the performance of lithium *** the various approaches to investigate battery aging,phase-field modelling(PFM)has emerged as a widely used...
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degradation of materials is one of the most critical aging mechanisms affecting the performance of lithium *** the various approaches to investigate battery aging,phase-field modelling(PFM)has emerged as a widely used numerical method for simulating the evolution of the phase interface as a function of space and time during material phase transition ***,PFM coupled with multi-physics analyses is particularly well-suited for investigating the mesoscale microstructural evolution of materials,providing quantitative understandings of aging and failure mechanisms in lithium *** this paper,we comprehensively overview the state-of-art applications of PFM in the research of degradation and failure processes in lithium batteries,particularly focusing on the theoretical framework anddevelopment of the PFMs for lithium deposition/dissolution,phase separation,and crack ***,we summarize the existing challenges and prospect some future developments in PFMs,aiming to offer new insights into the advancement of PFM and ultimately enhance the development of lithium batteries.
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