An accurate and computationally efficient determination of the cross sections for electron collision ionization of molecules has various applications, such as plasma physics and atmospheric science. ...In the case of large molecules, ab initio calculations are often difficult and time‐consuming. Here, we develop a feed forward neural network to predict the electron impact ionization cross sections of complex molecules. The training (predicting) set in the method consists of a series of theoretical ionization cross sections for small (large) molecules obtained from the combined model, which integrates the Binary‐Encounter‐Bethe and Deutsch‐Märk models. Several complex systems or targets involving electron collision ionization are evaluated, including molecules such as CH4$$ {}_4 $$, C3$$ {}_3 $$H8$$ {}_8 $$, C5$$ {}_5 $$H8$$ {}_8 $$, C6$$ {}_6 $$H10$$ {}_{10} $$, C6$$ {}_6 $$, C2$$ {}_2 $$H6$$ {}_6 $$O, and C6$$ {}_6 $$H6$$ {}_6 $$O. The root mean square errors of the trained and predicted cross sections by the 2×3×3×1$$ 2\times 3\times 3\times 1 $$ neural network (compared to the values from the combined model) are found to be approximately .0086 and .0930 (in 10−20$$ {}^{-20} $$ cm2$$ {}^2 $$), respectively, (using the C2$$ {}_2 $$H6$$ {}_6 $$O molecule as an example), indicating our results are very high accuracy. The excellent agreement between the predicted values and the actual values indicates that the neural network is a practical and powerful tool for determining the electron collision ionization cross sections of complex molecules and can provide valuable insights into the dynamics process. Apart from its fundamental importance, this study has far‐reaching implications for gas discharge, low‐temperature plasmas, and fusion edge plasmas and so forth.
This article describes the application of a feed‐forward neural network to estimate the ionization cross sections of electron collisions with complex molecules. The agreement between the predicted results and other theoretical results highlights the utility and effectiveness of the neural network. The present work contributes significantly to our understanding of the dynamical processes involved.
Baicalin is reported as an effective drug for ulcerative colitis (UC). However, its effect on gut microbiota and short-chain fatty acids (SCFAs) remains unknown. In this study, we investigated the ...role of baicalin on Th17/Treg balance, gut microbiota community, and SCFAs levels in trinitrobenzene sulphonic acid (TNBS)-induced UC rat model. We found the DAI scores were significantly increased in the TNBS-treated rats, while reduced in the baicalin-treated group in a dose-dependent manner, accompanied with the alleviation of mucosal injury, the reduction of ZO-1, Occludin, and MUC2 expression. At the meanwhile, baicalin repressed the increased levels of reactive oxygen species (ROS) and MDA, while deceased the GSH and SOD levels in colon tissue of rats treated with TNBS. On the other hand, administration of baicalin attenuated the TNBS-induced upregulations of Th17/Treg ratio, indicating a strong amelioration in the colorectal inflammation. More importantly, pyrosequencing of the V4 regions of 16S rRNA genes in rat feces revealed a deviation of the gut microbiota in response to baicalin treatment. In particular, the decreased
Firmicutes
-to-
Bacteroidetes
ratios and endotoxin-bearing
Proteobacteria
levels indicated that baicalin reversed TNBS-induced gut dysbiosis OTUs. In addition, we further investigated the fecal levels of major SCFAs in rats and found that baicalin significantly resorted the fecal butyrate levels in rats treated with TNBS. The increased butyrate levels were in consistent with the higher abundance of butyrate-producing species such as
Butyricimonas
spp.,
Roseburia
spp.,
Subdoligranulum
spp., and
Eubacteriu
spp. in baicalin-treated group. In conclusion, our findings suggest that baicalin possibly protected rats against ulcerative colitis by regulation of Th17/Treg balance, and modulation of both gut microbiota and SCFAs. Baicalin may be used as a prebiotic agent to treat ulcerative colitis-associated inflammation and gut dysbiosis.
Calculations of the electron-impact excitation (EIE) of singly charged Ca
+
and Ba
+
ions and subsequent de-excitation process are performed using a fully relativistic distorted wave (RDW) method. To ...resolve the discrepancy between previous theory and experiment, careful consideration is given to the generation of the target state wave-functions through the systematic inclusion of electron correlations. It is found that the electron correlation effects play a significant role on the cross section, while the effects on the linear polarization of the emitted radiation are relatively small. Good agreement between our result and experiment is obtained.
Graphical abstract
In this manuscript, we suggest a relativistic distorted wave approach for the prediction of structural properties and photoionization cross sections of highly charged ions in a non-ideal classical ...plasma (NICP) environment. The pseudopotential, obtained from a sequential solution of the Bogolyubov chain equations, is used to describe screened interactions in the plasma. We solve the Dirac equation to obtain wave functions and energies. Detailed calculations are carried out for the photoionization of the highly ionized H-like S
15
+
ions for an illustrative purpose. The NICP effects on the energies, transition rates, ionization potentials, and photoionization cross sections are investigated. Comparing our results with other available experimental and theoretical data, we find satisfactory agreement. Apart from its fundamental importance, the present study has implications for a range of fields, including astrophysics, nuclear fusion and laboratory plasma experiments.
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This paper proposes an innovative and high efficiency process to fabricate Cr-Ni stainless steel components using a double-wire feed and plasma arc additive manufacturing process ...(DWF-PAM). The superior characteristics exhibited by DWF-PAM processing in terms of the bead appearance, microstructure, and mechanical properties of all the test components, were investigated. The results show that, at the same process parameters, in contrast to the single-wire feed and plasma additive manufacturing (SWF-PAM) process, the deposition rate in the DWF-PAM process increased by 1.06 times on an average. A large number of complete grown equiaxed ferrite (CGEF) grains were found in the interface area close to the next layer of the DWF-PAM-processed sample; while for the SWF-PAM-processed samples, incomplete grown equiaxed ferrite grains were observed in same area. The CGEF grains provided a significant improvement to the ultimate tensile strengths and elongation rates of the DWF-PAM-processed samples. The ultimate tensile strength increased by 10.2% on an average, while the maximal increment of the elongation rate reached 176%. In view of these results, components manufactured by the DWF process can have a finer-grained microstructure and superior mechanical properties compared to those manufactured by the SWF process. Moreover, a higher deposition rate can also be achieved with the DWF-PAM process.
CRISPR/Cas enables precise improvement of commercially relevant crop species by transgenic and nontransgenic methodologies. We have used CRISPR/Cas with or without DNA repair template in both corn ...and soybean for a range of applications including enhancing drought tolerance, improving seed oil composition, and endowing herbicide tolerance. Importantly, by pairing CRISPR/Cas technology with recent advances in plant tissue culture, these changes can be introduced directly into commercially relevant genotypes. This powerful combination of technologies enables advanced breeding techniques for introducing natural genetic variations directly into product relevant lines with improved speed and quality compared with traditional breeding methods. Variation generated through such CRISPR/Cas enabled advanced breeding approaches can be indistinguishable from naturally occurring variation and therefore should be readily accessible for commercialization. The precision, reach, and flexibility afforded by CRISPR/Cas promise an important role for genome editing in future crop improvement efforts.
•Effects of key parameters on SPT with various S-CO2 Brayton cycles are analyzed.•Multi-objective optimization of SPT with different S-CO2 cycles are performed.•Different S-CO2 cycles are compared ...for applications in SPT based on Pareto fronts.
Supercritical CO2 (S-CO2) Brayton cycles are recently proposed to be integrated into the solar power tower (SPT) due to their high efficiency and compactness. Comparison of different S-CO2 Brayton cycle layouts is of great significance for selecting a suitable one in the SPT plant. Both of the efficiency and specific work are important performance criteria for the SPT plant. However, previous studies compared only one individual criterion, or both of them just separately. This paper puts forward a systematic comparison of different S-CO2 Brayton cycle layouts based on multi-objective optimizations. The two performance criteria are compared simultaneously between different S-CO2 cycle layouts by comparing the Pareto optimal fronts obtained from multi-objective optimizations. The results suggest that the inter-cooling cycle layout and the partial-cooling cycle layout can generally yield the most excellent performances, and followed by the recompression cycle layout and the pre-compression cycle layout, while the simple recuperation cycle layout has the worst performances. The advantages of the partial-cooling cycle layout and the inter-cooling cycle layout are more prominent compared with the other cycle layouts in the case of high compressor inlet temperature. The provided systematic comparison can be helpful in selecting the most suitable cycle layout for the application in SPT when there are specified requirements for the efficiency and the specific work. In addition, novel salts with high upper limit temperature (higher than 650 °C) are recommended to be developed as the heat transfer fluid for improving system performances.
As a widespread natural disaster, drought has a significant impact on changes in regional vegetation cover. Based on 1‐month standardized precipitation index (SPI1), this study took the Yellow River ...basin (YRB) with frequent droughts as the research object, using NDVI data from 1999 to 2018, Mann–Kendall trend test, and correlation test to study the temporal and spatial characteristics of meteorological drought, explored the response of vegetation cover to meteorological drought, and further discussed the possible factors affecting meteorological drought. The results of the study showed that from 1999 to 2018, the SPI1 in the YRB had not increased significantly in a large area in different months (p > .05). On the monthly time scale, the NDVI of the YRB gradually increased from north to south, showing a significant increasing trend the central area (p < .05). And in the summer months, there was a significant positive correlation between SPI1 and NDVI in some areas (p < .05). In the meantime, sunspots, ENSO, and PDO had significant effects on the SPI1 in the YRB (p < 0.05). Furthermore, in areas with frequent extreme droughts, the average value of NDVI was high, which was mainly because the area was in a cultivated vegetation area with a wide‐scale policy of returning farmland to forest and afforestation activities. Returning farmland to forests and afforestation activities will help overcome the impact of meteorological drought and other adverse conditions on vegetation. Therefore, returning farmland to forests can be implemented for ecological restoration in arid areas in the YRB.
Correlation between SPI1 and NDVI in different months of the Yellow River basin.
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