15,509 research outputs found
Research on force control system of lead cathode leveler
The flatness of the lead cathode plate affects the electrolytic efficiency of lead and the production efficiency of the whole lead electrolytic industry. However, the dynamic response of the force control system of the leveler is slow, and the anti-interference and robustness are poor. By comparing proportion integration differentiation (PID) control and feedback linearized synovial control two control strategies, MATLAB software was used for modeling and simulation analysis. The results show that the system with feedback linearized sliding mode control has faster response, higher precision and better robustness
Combining multitemporal optical and SAR data for LAI imputation with BiLSTM network
The Leaf Area Index (LAI) is vital for predicting winter wheat yield.
Acquisition of crop conditions via Sentinel-2 remote sensing images can be
hindered by persistent clouds, affecting yield predictions. Synthetic Aperture
Radar (SAR) provides all-weather imagery, and the ratio between its cross- and
co-polarized channels (C-band) shows a high correlation with time series LAI
over winter wheat regions. This study evaluates the use of time series
Sentinel-1 VH/VV for LAI imputation, aiming to increase spatial-temporal
density. We utilize a bidirectional LSTM (BiLSTM) network to impute time series
LAI and use half mean squared error for each time step as the loss function. We
trained models on data from southern Germany and the North China Plain using
only LAI data generated by Sentinel-1 VH/VV and Sentinel-2. Experimental
results show BiLSTM outperforms traditional regression methods, capturing
nonlinear dynamics between multiple time series. It proves robust in various
growing conditions and is effective even with limited Sentinel-2 images.
BiLSTM's performance surpasses that of LSTM, particularly over the senescence
period. Therefore, BiLSTM can be used to impute LAI with time-series Sentinel-1
VH/VV and Sentinel-2 data, and this method could be applied to other
time-series imputation issues
An analysis of the X-ray emission from the supernova remnant 3C397
The ASCA SIS and the ROSAT PSPC spectral data of the SNR 3C397 are analysed
with a two-component non-equilibrium ionization model. Besides, the ASCA SIS0
and SIS1 spectra are also fitted simultaneously in an equilibrium case. The
resulting values of the hydrogen column density yield a distance of \sim8\kpc
to 3C397. It is found that the hard X-ray emission, containing S and Fe
K lines, arises primarily from the hot component, while most of the
soft emission, composed mainly of Mg, Si, Fe L lines, and continuum, is
produced by the cool component. The emission measures suggest that the remnant
evolves in a cloudy medium and imply that the supernova progenitor might not be
a massive early-type star. The cool component is approaching ionization
equilibrium. The ages estimated from the ionization parameters and dynamics are
all much greater than the previous determination. We restore the X-ray maps
using the ASCA SIS data and compare them with the ROSAT HRI and the NRAO VLA
Sky Survey (NVSS) 20 cm maps. The morphology with two bright concentrations
suggests a bipolar remnant encountering a denser medium in the west.Comment: 20 pages, aasms4.sty, 3 figures To appear in ApJ (1999
Molybdenum Evidence for Inherited Planetary Scale Isotope Heterogeneity of the Protosolar Nebula
Isotope anomalies provide important information about early solar system
evolution. Here we report molybdenum isotope abundances determined in samples
of various meteorite classes. There is no fractionation of molybdenum isotopes
in our sample set within 0.1 permil and no contribution from the extinct
radionuclide 97Tc at mass 97 (97Tc/92Mo<3E-6). Instead, we observe clear
anomalies in bulk iron meteorites, mesosiderites, pallasites, and chondrites
characterized by a coupled excess in p- and r- or a mirror deficit in s-process
nuclides (Mo-HL). This large scale isotope heterogeneity of the solar system
observed for molybdenum must have been inherited from the interstellar
environment where the sun was born, illustrating the concept of ``cosmic
chemical memory''. The presence of molybdenum anomalies is used to discuss the
filiation between planetesimals.Comment: 7 pages, 2 figures, 1 table, accepted in Ap
Bell violation versus geometric measure of quantum discord and their dynamical behavior
Motivated by recent numerous works on the interplay among various measures of
quantum correlations, we aim to investigate the relationship between the
violation of Clauser-Horne-Shimony-Holt (CHSH) Bell inequality and geometric
measure of quantum discord for two-qubit systems. Exact lower and upper bounds
of Bell violation versus geometric discord are obtained for a specific and
significant class of states, Bell diagonal states, and the respective states
which suffice those bounds are also characterized. The dynamical behavior of
these two quantifiers is carefully analyzed in the presence of decoherence,
including Markovian, non-Markovian, and non-back-action quantum environments.
The results suggest that Bell violation is closely related to geometric
discord, like its relationship with other entanglement monotones.Comment: Published version. 9 pages, 16 figure
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