Soil aggregate size significantly impacts microbial communities and soil respiration. Soil total porosity and pH can regulate the distribution of soil bacteria and fungal communities within ...aggregates, thereby influencing soil respiration. However, it is unclear how it affects the microbial community composition distributed in soil aggregates, especially for fungal communities. The roles of soil total porosity and pH in controlling the microbial composition of soil aggregates are also unknown. In this study, we used high-throughput sequencing of the 16S rRNA and ITS gene regions to target bacterial and fungal members of aggregate samples of four sizes (2–4 mm, 1–2 mm, 0.25–1 mm and <0.25 mm). Our results showed that high respiration occurred in soil aggregates of 2–4 mm and 1–2 mm when there was high soil total porosity and low soil pH than in aggregates of 0.25–1 mm and <0.25 mm. Moreover, soil aggregates of 2–4 mm and 1–2 mm were dominated by four bacterial families (Oxalobacteraceae, Sphingomonadaceae, Cytophagaceae and Gemmatimonadaceae) and two fungal families (Lasiosphaeriaceae and Rhizophlyctidaceae), while the 0.25–1 mm and <0.25 mm aggregates were dominated by two bacterial families (Bacillaceae and Clostridiaceae) and one fungal family (Nectriaceae). Our results suggest that soil organic carbon and total porosity positively influenced the bacterial Shannon index, which led to a further positive influence on soil aggregate respiration, while soil pH positively affected the soil fungal Shannon index, leading to increased negative control of the respiration of soil aggregates.
The structural equation modeling (SEM) results show that soil total porosity could directly influence soil respiration. In addition, soil organic carbon and total porosity had a significantly positive direct effect on bacterial Shannon index. Additionally, the soil pH showed a direct negative effect on fungal Shannon index and soil respiration. Soil bacterial and fungal Shannon index had a significantly positive and negative direct effect on soil respiration, respectively. Our study suggests that the difference distribution of soil organic carbon, pH, total porosity in aggregates controlling the soil microbial diversity, and then affect soil aggregate respiration. Display omitted
•Soil aggregates size significantly impacts microbial communities and soil respiration.•High respiration occurred in macro-aggregates with high soil total porosity and low soil pH.•Soil bacterial Shannon index positively influenced the soil respiration.•Soil fungal Shannon index negatively affected the soil respiration.
This paper proposes a framework to perform the sensor classification by using multivariate time series sensors data as inputs. The framework encodes multivariate time series data into two-dimensional ...colored images, and concatenate the images into one bigger image for classification through a Convolutional Neural Network (ConvNet). This study applied three transformation methods to encode time series into images: Gramian Angular Summation Field (GASF), Gramian Angular Difference Field (GADF), and Markov Transition Field (MTF). Two open multivariate datasets were used to evaluate the impact of using different transformation methods, the sequences of concatenating images, and the complexity of ConvNet architectures on classification accuracy. The results show that the selection of transformation methods and the sequence of concatenation do not affect the prediction outcome significantly. Surprisingly, the simple structure of ConvNet is sufficient enough for classification as it performed equally well with the complex structure of VGGNet. The results were also compared with other classification methods and found that the proposed framework outperformed other methods in terms of classification accuracy.
A traction drive control system (TDCS) plays an important role in safety running of high-speed trains. This paper presents a new fault-injection strategy for safety testing and fault diagnosis ...verification in the TDCS. First, the fault scenarios on the signal level of each faulty component are analyzed. Then, the fault-injection method based on signal conditioning is proposed, and the injected signal, reflecting the fault scenario at a fault point, is generated to simulate the fault scenarios. Subsequently, the injected signal benchmark is constructed for all faults in traction converters, traction motors, sensors, and traction control units. Finally, a fault-injection benchmark platform is developed to simulate various fault scenarios in the TDCS. The simulation and comparison results show that the presented strategy is effective and easy to implement.
A method for the regiodivergent and stereoselective hydrosilylation of the basic industrial feedstock isoprene with unactivated silanes has been developed using earth‐abundant iron catalysts. The ...manipulation of regioselectivity relies on fine modification of the coordination geometry of the iron center. While a bidentate pyridine imine ligand promoted the formation of allylic silanes through 4,1‐addition, selectivity for the 3,4‐adduct homoallylic silanes was observed with a tridentate nitrogen ligand. Experimental studies and analysis were carried out to elucidate the reaction mechanism and the factors enabling manipulation of the regioselectivity. This study contributes to the art of regioselectivity control in alkene hydrofunctionalization.
A ligand‐regulated regiodivergent and stereoselective hydrosilylation of terpenes has been developed using earth‐abundant iron catalysts. Various silanes and terpenes were transformed with excellent selectivity into the corresponding allylic silanes and homoallylic silanes through 4,1‐ and 3,4‐addition, respectively.
The emergence of radical chemistry as well as green chemistry in organic synthesis has initiated an interest in photochemistry over the past decade. With catalytic amounts of photoredox catalysts ...under light irradiation, high active radical species are produced, which could trigger the subsequent organic transformations smoothly. Among the various photoredox reactions, photo‐catalytic C–S bond formation continues to thrive, as the C–S bond is indispensable in many important biological and pharmaceutical compounds. Great attention has been devoted to this area as illustrated by the series of papers on sulfone and sulfoxide skeleton synthesis under irradiation published in the past years. This review summarizing the recent advances in photo‐catalyzed sulfones and sulfoxide formation is arranged by reaction type together with the sulfur source covering sulfonylation and sulfinylation reactions. It is intended to provide readers with a comprehensive understanding of photo‐catalytic C‐S bond formation and offer help for future research.
High soil salinity is the main factor that limits soil microbial activity in the Yellow River Delta (YRD); however, its effects on fungal community and ecological function are unknown. Here, we ...comparatively investigated the diversity and structures of soil fungal communities targeting the internally transcribed fungal spacer gene using Illumina MiSeq sequencing methods under a salt gradient with five levels, namely, Low: low-salinity soil, Medium: medium-salinity soil, High: high-salinity soil, Extreme: extreme-salinity soil, and a non-salted site as the control (Non-saline). The results show that bulk density (BD) values significantly increased (
< 0.05), while significantly lower values of soil total carbon (TC), total nitrogen (TN), and fungal Shannon and Chao indexes were observed as the salinization gradient increased (
< 0.05). The relatively high levels of the families
and
distinguished two of the clusters, indicating two enterotypes of low (Non-saline and Low) and high (Medium, High, and Extreme) salinity soils, respectively. The family
was most abundant in the networks, and the positive correlations were more pronounced than negative correlations; however,
was the family most negatively correlated with others based on the network analysis. At the ecological function level, plant saprotrophs and litter saprotroph were significantly less abundant in extremely saline soil than non-saline soil. The change in soil properties (TC, TN, and BD) caused by soil salinization salt and electrical conductivity (EC) regulated the diversity of soil fungal communities, and ecological function, as indicated by Pearson correlation analyses. We suggest further investigation into the ecological functions of soil microorganisms in the extremely saline-alkaline soils of the YRD.
The basic industrial feedstock isoprene was employed as a building block to install prenyl and reverse‐prenyl groups onto indoles. The regioselectivity can be manipulated by the choice of metal ...hydride. Reverse‐prenylated indoles were attained with high selectivity when using Rh−H. By switching to a Pd−H catalyst, selectivity toward prenylated indoles was achieved. This regiodivergent method also features high atom economy without stoichiometric byproduct formation.
Backwards and forwards: A metal hydride mediated regiodivergent coupling of indoles with the industrial feedstock isoprene was developed for which the regioselectivity for prenylation versus reverse prenylation is determined by the choice of metal hydride. This method enables the installation of prenyl and reverse‐prenyl motifs onto indoles with high atom economy.
The recently discovered self-heating lithium ion battery has shown rapid self-heating from subzero temperatures and superior power thereafter, delivering a practical solution to poor battery ...performance at low temperatures. Here, we describe and validate an electrochemical-thermal coupled model developed specifically for computational design and improvement of the self-heating Li-ion battery (SHLB) where nickel foils are embedded in its structure. Predicting internal cell characteristics, such as current, temperature and Li-concentration distributions, the model is used to discover key design factors affecting the time and energy needed for self-heating and to explore advanced cell designs with the highest self-heating efficiency. It is found that ohmic heat generated in the nickel foil accounts for the majority of internal heat generation, resulting in a large internal temperature gradient from the nickel foil toward the outer cell surface. The large through-plane temperature gradient leads to highly non-uniform current distribution, and more importantly, is found to be the decisive factor affecting the heating time and energy consumption. A multi-sheet cell design is thus proposed and demonstrated to substantially minimize the temperature gradient, achieving 30% more rapid self-heating with 27% less energy consumption than those reported in the literature.
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•We present & validate the first model for a new class of self-heating Li-ion batteries.•Non-uniform temperature and current distributions in a SHLB are predicted.•Internal temperature gradient greatly affects self-heating time & energy consumption.•Multi-sheet design with optimized self-heating time & energy consumption is proposed.
The streaming instability is a promising mechanism to overcome the barriers in direct dust growth and lead to the formation of planetesimals. Most previous studies of the streaming instability, ...however, were focused on a local region of a protoplanetary disk with a limited simulation domain such that only one filamentary concentration of solids has been observed. The characteristic separation between filaments is therefore not known. To address this, we conduct the largest-scale simulations of the streaming instability to date, with computational domains up to 1.6 gas scale heights both horizontally and vertically. The large dynamical range allows the effect of vertical gas stratification to become prominent. We observe more frequent merging and splitting of filaments in simulation boxes of high vertical extent. We find multiple filamentary concentrations of solids with an average separation of about 0.2 local gas scale heights, much higher than the most unstable wavelength from linear stability analysis. This measures the characteristic separation of planetesimal forming events driven by the streaming instability and thus the initial feeding zone of planetesimals.
Battery thermal management systems (BTMSs) are expected to keep the battery temperature at a moderate level (∼30 °C) to minimize the thermally exacerbated degradation. However, during fast charging, ...a strong cooling system is required to restrict the temperature rise of Li-ion batteries (LiBs), which significantly increases the cost and weight of battery packs, and induces a large temperature variation inside the battery. In this work we find that all these drawbacks could be relieved by allowing LiBs to charge at higher temperatures. Since the fast charging of a LiB only takes a tiny fraction of its lifetime, the aging rate is limited even at a charging temperature of 60 °C. Three types of thermal environments are proposed: kept constant at 30 °C, preheated to 60 °C, and adiabatic fast charging. With an experimentally validated electrochemical-thermal (ECT) coupled model, we explore the interplay between thermal management and the fast-charging performance. It is found that a gradually increasing temperature profile is the best option to balance the lithium plating and thermal management of the battery. Combining adiabatic fast charging with a preheating step, we can achieve minimal cooling need, perfect temperature uniformity within a battery, and fast-charging capability simultaneously.
•Evaluate the cooling requirement and temperature uniformity of fast charging LiBs.•Predict the fast-charging capability of LiBs under different thermal environments.•Propose a thermal modulation method to achieve fast charging with zero cooling.
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