Fast-charging and high-energy-density batteries pose significant safety concerns due to high rates of heat generation. Understanding how localized high temperatures affect the battery is critical but ...remains challenging, mainly due to the difficulty of probing battery internal temperature with high spatial resolution. Here we introduce a method to induce and sense localized high temperature inside a lithium battery using micro-Raman spectroscopy. We discover that temperature hotspots can induce significant lithium metal growth as compared to the surrounding lower temperature area due to the locally enhanced surface exchange current density. More importantly, localized high temperature can be one of the factors to cause battery internal shorting, which further elevates the temperature and increases the risk of thermal runaway. This work provides important insights on the effects of heterogeneous temperatures within batteries and aids the development of safer batteries, thermal management schemes, and diagnostic tools.
Doped semiconductors are the most important building elements for modern electronic devices1. In silicon-based integrated circuits, facile and controllable fabrication and integration of these ...materials can be realized without introducing a high-resistance interface2,3. Besides, the emergence of two-dimensional (2D) materials enables the realization of atomically thin integrated circuits4–9. However, the 2D nature of these materials precludes the use of traditional ion implantation techniques for carrier doping and further hinders device development10. Here, we demonstrate a solvent-based intercalation method to achieve p-type, n-type and degenerately doped semiconductors in the same parent material at the atomically thin limit. In contrast to naturally grown n-type S-vacancy SnS2, Cu intercalated bilayer SnS2 obtained by this technique displays a hole field-effect mobility of ~40 cm2 V−1 s−1, and the obtained Co-SnS2 exhibits a metal-like behaviour with sheet resistance comparable to that of few-layer graphene5. Combining this intercalation technique with lithography, an atomically seamless p–n–metal junction could be further realized with precise size and spatial control, which makes in-plane heterostructures practically applicable for integrated devices and other 2D materials. Therefore, the presented intercalation method can open a new avenue connecting the previously disparate worlds of integrated circuits and atomically thin materials.
Abstract
Electrochemical intercalation of ions into the van der Waals gap of two-dimensional (2D) layered materials is a promising low-temperature synthesis strategy to tune their physical and ...chemical properties. It is widely believed that ions prefer intercalation into the van der Waals gap through the edges of the 2D flake, which generally causes wrinkling and distortion. Here we demonstrate that the ions can also intercalate through the top surface of few-layer MoS
2
and this type of intercalation is more reversible and stable compared to the intercalation through the edges. Density functional theory calculations show that this intercalation is enabled by the existence of natural defects in exfoliated MoS
2
flakes. Furthermore, we reveal that sealed-edge MoS
2
allows intercalation of small alkali metal ions (
e.g
., Li
+
and Na
+
) and rejects large ions (e.g., K
+
). These findings imply potential applications in developing functional 2D-material-based devices with high tunability and ion selectivity.
The aim of this study was to identify factors associated with the death of patients with COVID-19 pneumonia caused by the novel coronavirus SARS-CoV-2.All clinical and laboratory parameters were ...collected prospectively from a cohort of patients with COVID-19 pneumonia who were hospitalised to Wuhan Pulmonary Hospital (Wuhan City, Hubei Province, China) between 25 December 2019 and 7 February 2020. Univariate and multivariate logistic regression analysis revealed that age ≥65 years (OR 3.765, 95% CI 1.146–17.394; p=0.023), pre-existing concurrent cardiovascular or cerebrovascular diseases (OR 2.464, 95% CI 0.755–8.044; p=0.007), CD3+CD8+ T-cells ≤75 cells·μL−1 (OR 3.982, 95% CI 1.132–14.006; p<0.001) and cardiac troponin I ≥0.05 ng·mL−1 (OR 4.077, 95% CI 1.166–14.253; p<0.001) were associated with an increase in risk of mortality from COVID-19 pneumonia.” has been corrected to: “Univariate and multivariate logistic regression analysis revealed that age ≥65 years (OR 3.765, 95% CI 1.201−11.803; p=0.023), pre-existing concurrent cardiovascular or cerebrovascular diseases (OR 2.464, 95% CI 1.279−4.747; p=0.007), CD3+CD8+ T-cells ≤75 cells·μL−1 (OR 3.982, 95% CI 1.761–9.004; p<0.001) and cardiac troponin I ≥0.05 ng·mL−1 (OR 4.077, 95% CI 1.778–9.349; p<0.001) were associated with an increase in risk of mortality from COVID-19 pneumonia. In a sex-, age- and comorbid illness-matched case-control study, CD3
CD8
T-cells ≤75 cells·μL
and cardiac troponin I ≥0.05 ng·mL
remained as predictors for high mortality from COVID-19 pneumonia.We identified four risk factors: age ≥65 years, pre-existing concurrent cardiovascular or cerebrovascular diseases, CD3
CD8
T-cells ≤75 cells·μL
and cardiac troponin I ≥0.05 ng·mL
The latter two factors, especially, were predictors for mortality of COVID-19 pneumonia patients.
In order to improve the position high-precision synchronization performance of multi-motor synchronous control, a multi-motor position synchronization control method based on non-singular fast ...terminal sliding mode control (NFTSMC) combined with an improved deviation coupling control structure (Improved Deviation Coupling Control(IDCC), NFTSMC+IDCC). Firstly, this paper designs a sliding mode controller using a non-singular fast terminal sliding mode surface with a Permanent Magnet Synchronous Motor (PMSM) as the control object. Secondly, the deviation coupling is improved to enhance the coupling between multiple motors and achieve position synchronization. Finally, the simulation results show that the total error of multi-motor position synchronization under NFTSMC control is 0.553r in the simulation of multi-motor synchronization control under the same working conditions, which is 2.873r and 1.772r less than that of SMC and FTSMC in terms of speed error, and the anti-disturbance performance is 83.68% and 76.22% higher than that of both of them, respectively. In the subsequent simulation of the improved multi-motor position synchronization structure, the total error of the multi-motor position is in the range of 0.56r-0.58r at three speeds, which is much smaller than the synchronization error under the Ring Coupling Control (RCC) structure and Deviation Coupling Control (DCC) structure, showing a better The synchronization error is much smaller than that of the RCC structure and DCC structure, which shows better position synchronization performance. Therefore, the multi-motor position synchronization control method proposed in this paper has a good position synchronization effect and achieves the control effect of small displacement error and fast convergence of the multi-motor position synchronization control system after being disturbed, the control performance is significantly improved.
Ulcerative colitis (UC) is a chronic, nonspecific inflammatory bowel disease (IBD) characterized by complicated and relapsing inflammation in the gastrointestinal tract. SM934 is a water-soluble ...artemisinin analogue that shows anti-inflammatory and immuno-regulatory effects. In this study, we investigated the effects of SM934 on UC both in vivo and in vitro. A mouse model of colitis was established in mice by oral administration of 5% dextran sulfate sodium (DSS). SM934 (3, 10 mg/kg per day, ig) was administered to the mice for 10 days. After the mice were sacrificed, colons, spleens and mesenteric lymph nodes (MLNs) were collected for analyses. We showed that SM934 administration restored DSS-induced body weight loss, colon shortening, injury and inflammation scores. Furthermore, SM934 administration significantly decreased the disease activity index (DAI), histopathological scores, and myeloperoxidase (MPO) activities in colonic tissues. Moreover, SM934 administration dose-dependently decreased the mRNA and protein levels of DSS-induced pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α), and the percentage of macrophages and neutrophils in colon tissues. The effects of SM934 on LPS-stimulated RAW 264.7 cells and THP-1-derived macrophages were examined in vitro. Treatment with SM934 (0.8, 8, 80 μmol/L) dose-dependently decreased the production of pro-inflammatory mediators in LPS-stimulated RAW264.7 cells and THP-1-derived macrophages via inhibiting activation of the NF-κB signaling. Our results reveal the protective effects of SM934 on DSS-induced colitis can be attributed to its suppressing effects on neutrophils and macrophages and its inhibitory role in the NF-κB signaling, suggests that SM934 might be a potential effective drug for ulcerative colitis.
A variety of methods including tuning chemical compositions, structures, crystallinity, defects and strain, and electrochemical intercalation have been demonstrated to enhance the catalytic activity. ...However, none of these tuning methods provide direct dynamical control during catalytic reactions. Here we propose a new method to tune the activity of catalysts through solid-state ion gating manipulation and adjustment (SIGMA) using a catalysis transistor. SIGMA can electrostatically dope the surface of catalysts with a high electron concentration over 5 × 1013 cm–2 and thus modulate both the chemical potential of the reaction intermediates and their electrical conductivity. The hydrogen evolution reaction (HER) on both pristine and defective MoS2 were investigated as model reactions. Our theoretical and experimental results show that the overpotential at 10 mA/cm2 and Tafel slope can be in situ, continuously, dynamically, and reversibly tuned over 100 mV and around 100 mV/dec, respectively.
Tomato bacterial wilt caused by Ralstonia solanacearum bacterium is a severe problem in Southern China, where relatively high environmental temperatures commonly prevails during the crop seasons. ...Previous research has indicated that bacterial wilt disease incidence generally increases during the warm months of summer leading to reduced tomato yield. Moreover, the efficacy of bio-organic fertilizers (BOFs)-organic compost fortified with pathogen-suppressive bacteria-is often lost during the periods of high environmental temperatures. Here we studied if the disease incidence could be reduced and the BOF performance enhanced by simply preponing and postponing the traditional seedling transplantation times to avoid tomato plant development during periods of high environmental temperature. To this end, a continuous, two-year field experiment was conducted to evaluate the performance of BOF in two traditional (late-spring LS and early-autumn EA) and two alternative (early-spring ES and late-autumn LA) crop seasons. We found that changing the transplantation times reduced the mean disease incidence from 33.9% (LS) and 54.7% (EA) to 11.1% (ES) and 7.1% (LA), respectively. Reduction in disease incidence correlated with the reduction in R. Solanacearum pathogen density in the tomato plant rhizosphere and stem base. Applying BOF during alternative transplantation treatments improved biocontrol efficiency from 43.4% (LS) and 3.1% (EA) to 67.4% (ES) and 64.8% (LA). On average, the mean maximum air temperatures were positively correlated with the disease incidence, and negatively correlated with the BOF biocontrol efficacy over the crop seasons. Crucially, even though preponing the transplantation time reduced the tomato yield in general, it was still economically more profitable compared to LS season due to reduced crop losses and relatively higher market prices. Preponing and postponing traditional tomato transplantation times to cooler periods could thus offer simple but effective way to control R. solanacearum disease outbreaks.
It has recently been shown that sulfur, a solid material in its elementary form S
, can stay in a supercooled state as liquid sulfur in an electrochemical cell. We establish that this newly ...discovered state could have implications for lithium-sulfur batteries. Here, through in situ studies of electrochemical sulfur generation, we show that liquid (supercooled) and solid elementary sulfur possess very different areal capacities over the same charging period. To control the physical state of sulfur, we studied its growth on two-dimensional layered materials. We found that on the basal plane, only liquid sulfur accumulates; by contrast, at the edge sites, liquid sulfur accumulates if the thickness of the two-dimensional material is small, whereas solid sulfur nucleates if the thickness is large (tens of nanometres). Correlating the sulfur states with their respective areal capacities, as well as controlling the growth of sulfur on two-dimensional materials, could provide insights for the design of future lithium-sulfur batteries.
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