55 research outputs found
Synthesis and electrochemical properties of Sn-SnO2/C nanocomposite
A Sn-Sn02/C nanocomposite was synthesized using the electrospinning method. Thermal analysis was used to determine the content range of Sn and Sn02 in the composite. The composite was characterized by X-ray diffraction, and the particle size and shape in the Sn-SnOiC composite were determined by scanning and transmission electron microscopy. The results show that the Sn-Sn02/C composite takes on a nanofiber morphology, with the diameters of the nanofibers distributed from 50 to 200 nm. The electrOChemical properties of the Sn-SnOiC composite were also investigated. The Sn-SnOiC composite as an electrode material has both higher reversible capacity (887 mAh· g-I). and good cycling performance in lithium-anode ceUs working at room temperature in a 3.0 V to O.Ot V potential window. The Sn-Sn02/C composite could relain a discharge capacity of 546 mAWg aller 30 cycles. The outstanding electrochemical properties of the Sn-SnOiC composite oblained by this method make it possible for Ihis composite to be used as a promising anode material
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Estimation of the hydraulic parameters of leaky aquifers based on pumping tests and coupled simulation/optimization: verification using a layered aquifer in Tianjin, China
Accurate estimates of aquifer parameters are necessary for effective groundwater management and for geotechnical engineering applications. Pumping tests may be employed to estimate the hydraulic conductivity in leaky aquifer/aquitard systems. This work introduces a hybrid algorithm with global search capacity (the Genetic algorithm, GA) and local search capacity—the Levenberg-Marquardt (LM) algorithm—coupled with a modified Neuman-Witherspoon solution for leaky aquifers to estimate the aquifer’s hydraulic parameters from pumping-test data. The GA is employed to determine the initial guesses of the aquifer parameter values. The optimal parameter values are then obtained with the LM algorithm, yielding a mixed GA/LM algorithm, herein named GALMA. Results show that the drawdown trends based on the estimated parameters agree well with measured drawdown. The proposed estimation algorithm identifies aquifer parameters with greater reliability than previous approaches. Verification of the GALMA is carried out based on three pumping tests in a layered aquifer in Tianjin, China, and on four historical case studies involving diverse hydrogeological settings. The excellent match between observed drawdown and GALMA-estimated parameters demonstrates the estimation accuracy and superior performance relative to previously reported estimation methods
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Correction: Estimation of the hydraulic parameters of leaky aquifers based on pumping tests and coupled simulation/optimization: verification using a layered aquifer in Tianjin, China
The correct email address for the corresponding author (Haizuo Zhou) is: [email protected]
Identifying and decoupling many-body interactions in spin ensembles in diamond
We simulate the dynamics of varying density quasi-two-dimensional spin
ensembles in solid-state systems, focusing on the nitrogen-vacancy centers in
diamond. We consider the effects of various control sequences on the averaged
dynamics of large ensembles of spins, under a realistic "spin-bath"
environment. We reveal that spin locking is efficient for decoupling spins
initialized along the driving axis, both from coherent dipolar interactions and
from the external spin-bath environment, when the driving is two orders of
magnitude stronger than the relevant coupling energies. Since the application
of standard pulsed dynamical decoupling sequences leads to strong decoupling
from the environment, while other specialized pulse sequences can decouple
coherent dipolar interactions, such sequences can be used to identify the
dominant interaction type. Moreover, a proper combination of pulsed decoupling
sequences could lead to the suppression of both interaction types, allowing
additional spin manipulations. Finally, we consider the effect of finite-width
pulses on these control protocols and identify improved decoupling efficiency
with increased pulse duration, resulting from the interplay of dephasing and
coherent dynamics
Glomerular Organization in the Antennal Lobe of the Oriental Fruit Fly Bactrocera dorsalis
The oriental fruit fly, Bactrocera dorsalis is one of the most destructive pests of horticultural crops in tropical and subtropical Asia. The insect relies heavily on its olfactory system to select suitable hosts for development and reproduction. To understand the neural basis of its odor-driven behaviors, it is fundamental to characterize the anatomy of its olfactory system. In this study, we investigated the anatomical organization of the antennal lobe (AL), the primary olfactory center, in B. dorsalis, and constructed a 3D glomerular atlas of the AL based on synaptic antibody staining combined with computerized 3D reconstruction. To facilitate identification of individual glomeruli, we also applied mass staining of olfactory sensory neurons (OSNs) and projection neurons (PNs). In total, 64 or 65 glomeruli are identifiable in both sexes based on their shape, size, and relative spatial relationship. The overall glomerular volume of two sexes is not statistically different. However, eight glomeruli are sexually dimorphic: four (named AM2, C1, L2, and L3) are larger in males, and four are larger in females (A3, AD1, DM3, and M1). The results from anterograde staining, obtained by applying dye in the antennal lobe, show that three typical medial, media lateral, and lateral antennal-lobe tracts form parallel connections between the antennal lobe and protocerebrum. In addition to these three tracts, we also found a transverse antennal-lobe tract. Based on the retrograde staining of the calyx in the mushroom body, we also characterize the arrangement of roots and cell body clusters linked to the medial antennal-lobe tracts. These data provide a foundation for future studies on the olfactory processing of host odors in B. dorsalis
Soybean \u3ci\u3eGm\u3c/i\u3eSAUL1, a Bona Fide U-Box E3 Ligase, Negatively Regulates Immunity Likely through Repressing the Activation of \u3ci\u3eGm\u3c/i\u3eMPK3
E3 ubiquitin ligases play important roles in plant immunity, but their role in soybean has not been investigated previously. Here, we used Bean pod mottle virus (BPMV)-mediated virusinduced gene silencing (VIGS) to investigate the function of GmSAUL1 (Senescence-Associated E3 Ubiquitin Ligase 1) homologs in soybean. When two closely related SAUL1 homologs were silenced simultaneously, the soybean plants displayed autoimmune phenotypes, which were significantly alleviated by high temperature, suggesting that GmSAUL1a/1b might be guarded by an R protein. Interestingly, silencing GmSAUL1a/1b resulted in the decreased activation of GmMPK6, but increased activation of GmMPK3 in response to flg22, suggesting that the activation of GmMPK3 is most likely responsible for the activated immunity observed in the GmSAUL1a/1b-silenced plants. Furthermore, we provided evidence that GmSAUL1a is a bona fide E3 ligase. Collectively, our results indicated that GmSAUL1 plays a negative role in regulating cell death and immunity in soybean
Blind Source Separation Based on Improved Wave-U-Net Network
With the development and widespread application of voice interaction technology, it has become crucial to improve the accuracy of blind source separation technology. In order to further enhance the separation results of vocal and accompaniment, this paper proposes an improved Wave-U-Net model. Based on the skip connection of the Wave-U-Net model, we propose a segmented attention module (SAM) consisting of a spatial attention module (SPAM) and a channel attention module (CAM) to replace the skip connections in this model to solve the semantic gap caused by feature concatenation. Furthermore, we replace the 1D convolution layer of the bottleneck layer in this model with an atrous spatial pyramid pooling (ASPP) module. The purpose is to increase the receptive field and obtain multi-scale features at the same time, thereby improving the speech separation performance of the model. We conduct experimental tests in the Musdb18 dataset, and analyze the performance of the model using the SDR, SIR and SAR evaluation indicators. The research results denote that compared with the Wave-U-Net network that only uses feature concatenation, the SDR values of the restored vocal and restored accompaniment are increased by 4.229dB and 4.626dB, respectively, and the separation performance is better than some existing baseline models
Effect of Pre-Existing Underground Structures on Groundwater Flow and Strata Movement Induced by Dewatering and Excavation
Based on an actual excavation of a metro station in Tianjin, China, a fluid–solid coupling numerical model was developed to study the characteristics of groundwater flow and strata movement induced by dewatering and excavation considering the barrier effect of pre-existing adjacent underground structures. Two parameters were selected for the model: the distance between the excavation and the existing underground structure (D), and the buried depth of the adjacent structure (H). By comparing the distribution of groundwater drawdown and deformation modes of the retaining structure and the strata under different working conditions, the influence mechanism of adjacent structures on the movement of groundwater and strata was revealed. The results show that the pile foundations have different effects on the groundwater flow and excavation deformation. Generally, the maximum groundwater drawdown could be enlarged by considering the adjacent underground structure, while the retaining structure deflection would be reduced and the ground settlement could be either enlarged or reduced. Additionally, as D decreases and H increases, a much greater groundwater drawdown and a much smaller retaining structure deflection would appear, which together affect the ground behavior. On the one hand, greater groundwater drawdown would lead to greater ground settlement by soil consolidation, while on the other hand, a smaller retaining structure deflection would lead to smaller ground settlement. Thus, a complex development of ground settlement would appear, and a specific analysis should be performed to assess this in practice, based on a specific H and D
Percutaneous nephrolithotomy versus open surgery for surgical treatment of patients with staghorn stones: A systematic review and meta-analysis.
OBJECTIVES:To compare the efficacy and safety of percutaneous nephrolithotomy (PCNL) and open surgery (OS) for surgical treatment of patients with staghorn stones based on published literatures. MATERIALS AND METHODS:A comprehensive literature search of Pubmed, Embase, CNKI and Cochrane Library was conducted to identify studies comparing outcomes of PCNL and OS for treating patients with staghorn stones up to Jan 2018. RESULTS:There was no significant difference in final-SFR between PCNL and OS (odds ratio[OR]: 1.17; 95% confidence interval [CI]: 0.64, 2.15; p = 0.61), while PCNL provided a significantly lower immediate-SFR compared with OS (OR: 0.29; 95% CI: 0.16, 0.51; P < 0.0001). PCNL provided significantly lower overall complication rate, shorter operative times, hospitalization times, less blood loss and blood transfusion compared with OS (OR: 0.59; 95% CI: 0.41, 0.84; P = 0.004), (weighted mean difference [WMD]: -59.01mins; 95% CI: -81.09, -36.93; p < 0.00001), (WMD: -5.77days; 95% CI: -7.80, -3.74; p < 0.00001), (WMD: -138.29ml; 95% CI: -244.98, -31.6; p = 0.01) and (OR: 0.44; 95% CI: 0.29, 0.68; P = 0.00002), respectively. No significant differences were found in minor complications (Clavien I-II) (OR: 0.72; 95% CI: 0.47, 1.09; p = 0.12) and major complications (Clavien III-V) (OR: 0.5; 95% CI: 0.23, 1.08; P = 0.08). In subgroup analysis, there were no significant differences for overall complications and operative times between mini-PCNL and OS. In sensitivity analysis, there was no significant difference for overall complications between PCNL and OS. CONCLUSION:Our analysis suggested that standard PCNL turns out to be a safe and feasible alternative for patients with staghorn stones compared to OS or mini-PCNL. Because of the inherent limitations of the included studies, further large sample, prospective, multi-centric and randomized control trials should be undertaken to confirm our findings
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