Reversible intercalation of methyl viologen as a dicationic charge carrier in aqueous batteries.

The interactions between charge carriers and electrode structures represent one of the most important considerations in the search for new energy storage devices. Currently, ionic bonding dominates the battery chemistry. Here we report the reversible insertion of a large molecular dication, methyl viologen, into the crystal structure of an aromatic solid electrode, 3,4,9,10-perylenetetracarboxylic dianhydride. This is the largest insertion charge carrier when non-solvated ever reported for batteries; surprisingly, the kinetic properties of the (de)insertion of methyl viologen are excellent with 60% of capacity retained when the current rate is increased from 100 mA g-1 to 2000 mA g-1. Characterization reveals that the insertion of methyl viologen causes phase transformation of the organic host, and embodies guest-host chemical bonding. First-principles density functional theory calculations suggest strong guest-host interaction beyond the pure ionic bonding, where a large extent of covalency may exist. This study extends the boundary of battery chemistry to large molecular ions as charge carriers and also highlights the electrochemical assembly of a supramolecular system

Abundant surface-semimetal phases in three-dimensional obstructed atomic insulators

Three-dimensional obstructed atomic insulators (OAIs) are characterized by the appearance of floating surface states (FSSs) at specific surfaces. Benefiting from this feature, our study here shows the presence of abundant surface-semimetal phases in 3D OAIs. The symmetries of obstructed Wannier charge centers ensure the degeneracy of such FSSs at high-symmetry points or invariant lines in the surface Brillouin zone. Utilizing topological quantum chemistry theory, we identify a carbon allotrope with a body-centered tetragonal structure, named bct-C20, as an ideal candidate for realizing different kinds of surface-semimetal phases. For the (001)surface of bct-C20, there are four in-gap FSSs, and these four FSSs form two kinds of surface Dirac cones, i.e., topological Dirac cones with linear dispersion and symmetry-enforced quadratic Dirac cones. The band topology of a surface Dirac cone is captured by the effective surface Hamiltonian and the emergence of hinge states. Moreover, the existence of the surface-nodal-line state is also discussed. This work reports an approach to obtain d-dimensional semimetal phases from the surface states of (d + 1)-dimensional systems, which is of great significance for the studies in revealing topological states and their practical applications in high-dimensional crystals.Comment: 6 pages, 4 figure

Persistent Upflows and Downflows at Active Region boundaries Observed by SUTRI and AIA

Upflows and downflows at active region (AR) boundaries have been frequently observed with spectroscopic observations at extreme ultraviolet (EUV) passbands. In this paper, we report the coexistence of upflows and downflows at the AR boundaries with imaging observations from the Solar Upper Transition Region Imager (SUTRI) and the Atmospheric Imaging Assembly (AIA). With their observations from 2022 September 21 to 2022 September 30, we find 17 persistent opposite flows occurring along the AR coronal loops. The upflows are prominent in the AIA 193 \AA images with a velocity of 50-200 km/s, while the downflows are best seen in the SUTRI 465 \AA and AIA 131 \AA images with a slower velocity of tens of kilometers per second (characteristic temperatures (log T(K)) for 193 \AA, 465 \AA and 131 \AA are 6.2, 5.7, 5.6, respectively). We also analyze the center-to-limb variation of the velocities for both upflows and downflows. The simultaneous observations of downflows and upflows can be explained by the chromosphere-corona mass-cycling process, in which the localized chromospheric plasma is impulsively heated to coronal temperature forming a upflow and then these upflows experience radiative cooling producing a downflow with the previously heated plasma returning to the lower atmosphere. In particular, the persistent downflows seen by SUTRI provide strong evidence of the cooling process in the mass cycle. For upflows associated with open loops, part of the plasma is able to escape outward and into the heliosphere as solar wind

Hydrological modeling in the Manas River Basin using soil and water assessment tool driven by CMADS

Hidrološka simulacija u meteorološki neispitanim područjima oduvijek je težak problem u proučavanju atmosferskih i hidroloških odnosa; to je također jedan od važnih faktora koji ograničavaju razvoj modela i spoznaju o izvoru vode u porječju. U svrhu analize atmosferskih i hidroloških odnosa; u radu se daje kvantitativna procjena promjene vodotokova u porječjima prekrivenim ledenjacima i snijegom, te je izabrano porječje rijeke Manas (Manas River Basin - MRB) u Kini kao tipično područje istraživanja u svrhu provjere prilagodljivosti meteoroloških podataka u Kini (China Meteorological Assimilation Driving Datasets) – CMADS, za model alata za procjenu tla i vode - Soil and Water Assessment Tool model (SWAT). Taj se model prvenstveno koristio za simulaciju izvora vode, a zatim smo ga kalibrirali s podacima CMADS-a, lokalizirali u porječje rijeke Manas (MRB), Kina, te konačno kalibrirali simulirano oticanje s dobivenim podacima SWAT-CUP (SWAT Calibration and Uncertainty Programs). Uz to, u ovo je istraživanje također uključena analiza osjetljivosti parametara te ocjena i kalibriranje parametara. Rezultati su pokazali da se modelom SWAT može dobro reproducirati proces oticanja vode na dva položaja istraživanog područja (Kenswat i Hongshanzui) primjenom podataka iz CMADS-a. Simulacija se pokazala uspješnom na osnovu podataka od mjesec dana na oba položaja gdje su R2 = (0,556÷0,999) i NSE = (0,937÷0,998), i dala zadovoljavajuće rezultate kod R2 = (0,927÷0,993) i NSE = (0,836÷0,997). Naše istraživanje pokazuje da se modelom SWAT mogu dobiti zadovoljavajući rezultati kalibriranjem parametara u područjima s visokim dotokom vode s vodenjaka. Uz to, CMADS može osigurati potrebne meteorološke podatke za SWAT simulacije i pomoći kod kalibriranja parametara i analize prikupljenih podataka s površine.Hydrological simulation in meteorological ungauged areas has always been a difficult problem for the study on atmospheric and hydrological coupling; meanwhile, it is also one of the important factors that restrict model development and basin water resource knowledge. To analyze the mechanism of atmospheric and hydrological coupling, this study quantitatively evaluated water cycle situation in basins covered with glaciers and snow, and chose the Manas River Basin (MRB) in China as the typical research area to verify the adaptability of the China Meteorological Assimilation Driving Datasets for the Soil and Water Assessment Tool model (CMADS). The SWAT model was firstly built to simulate water resources, then we calibrated the model with CMADS dataset and started localization in the Manas River Basin (MRB), China, and finally calibrated simulated runoff with observed data SWAT-CUP (SWAT Calibration and Uncertainty Programs). In addition, parameter sensitivity analysis, and parameter calibration and validation were also included in the present study. Results showed that the SWAT model could well reproduce the runoff process of two stations (Kenswat and Hongshanzui) in the research area by using data from CMADS. The simulation performed well on monthly scale in both stations, where R2 = (0,556÷0,999) and NSE = (0,937÷0,998), and also showed satisfactory effects, where R2 = (0,927÷0,993) and NSE = (0,836÷0,997).Our research suggests that the SWAT model can show satisfactory results through parameter calibration in areas with high glacial recharge rate. Moreover, CMADS can provide necessary meteorological data for SWAT simulations, and support parameter calibration and historical surface data analysis

Vegetation change and human-environment interactions in the Qinghai Lake Basin, northeastern Tibetan Plateau, since the last deglaciation

The nature of the interaction between prehistoric humans and their environment, especially the vegetation, has long been of interest. The Qinghai Lake Basin in North China is well-suited to exploring the interactions between prehistoric humans and vegetation in the Tibetan Plateau, because of the comparatively dense distribution of archaeological sites and the ecologically fragile environment. Previous pollen studies of Qinghai Lake have enabled a detailed reconstruction of the regional vegetation, but they have provided relatively little information on vegetation change within the Qinghai Lake watershed. To address the issue we conducted a pollen-based vegetation reconstruction for an archaeological site (YWY), located on the southern shore of Qinghai Lake. We used high temporal-resolution pollen records from the YWY site and from Qinghai Lake, spanning the interval since the last deglaciation (15.3 kyr BP to the present) to quantitatively reconstruct changes in the local and regional vegetation using Landscape Reconstruction Algorithm models. The results show that, since the lateglacial, spruce forest grew at high altitudes in the surrounding mountains, while the lakeshore environment was occupied mainly by shrub-steppe. From the lateglacial to the middle Holocene, coniferous woodland began to expand downslope and reached the YWY site at ∼ 7.1 kyr BP. The living environment of the local small groups of Paleolithic-Epipaleolithic humans (during 15.3–13.1 kyr BP and 9–6.4 kyr BP) changed from shrub-steppe to coniferous forest–steppe. The pollen record shows no evidence of pronounced changes in the vegetation community corresponding to human activity. However, based on a comparison of the local and regional vegetation reconstructions, low values of biodiversity and a significant increase in two indicators of vegetation degradation, Chenopodiaceae and Rosaceae, suggest that prehistoric hunters-gatherers likely disturbed the local vegetation during ∼ 9.0–6.4 kyr BP. Our findings are a preliminary attempt to study human-environment interactions at Paleolithic-Epipaleolithic sites in the region, and they contribute to ongoing environmental archaeology research in the Tibetan Plateau

Spring Flood Forecasting Based on the WRF-TSRM Mode

The snowmelt process is becoming more complex in the context of global warming, and the current existing studies are not effective in using the short-term prediction model to drive the distributed hydrological model to predict snowmelt floods. In this study, we selected the Juntanghu Watershed in Hutubi County of China on the north slope of the Tianshan Mountains as the study area with which to verify the snowmelt flood prediction accuracy of the coupling model. The weather research and forecasting (WRF) model was used to drive a double-layer distributed snowmelt runoff model called the Tianshan Snowmelt Runoff Model (TSRM), which is based on multi-year field snowmelt observations. Moreover, the data from NASA’s moderate resolution imaging spectroradiometer (MODIS) was employed to validate the snow water equivalent during the snow-melting period. Results show that, based on the analysis of the flow lines in 2009 and 2010, the WRF-driven TSRM has an overall 80% of qualification ratios (QRs), with determination coefficients of 0.85 and 0.82 for the two years, respectively, which demonstrates the high accuracy of the model. However, due to the influence of the ablation of frozen soils, the forecasted flood peak is overestimated. This problem can be solved by an improvement to the modeled frozen soil layers. The conclusion reached in this study suggests that the WRF-driven TSRM can be used to forecast short-term snowmelt floods on the north slope of the Tianshan Mountains, which can effectively improve the local capacity for the forecasting and early warning of snowmelt floods

The Solar Origin of an Intense Geomagnetic Storm on 2023 December 1st: Successive Slipping and Eruption of Multiple Magnetic Flux Ropes

The solar eruption that occurred on 2023 November 28 (SOL2023-11-28) triggered an intense geomagnetic storm on Earth on 2023 December 1. The associated Earth's auroras manifested at the most southern latitudes in the northern hemisphere observed in the past two decades. In order to explore the profound geoeffectiveness of this event, we conducted a comprehensive analysis of its solar origin to offer potential factors contributing to its impact. Magnetic flux ropes (MFRs) are twisted magnetic structures recognized as significant contributors to coronal mass ejections (CMEs), thereby impacting space weather greatly. In this event, we identified multiple MFRs in the solar active region and observed distinct slipping processes of the three MFRs: MFR1, MFR2, and MFR3. All three MFRs exhibit slipping motions at a speed of 40--137 km s$^{-1}$, extending beyond their original locations. Notably, the slipping of MFR2 extends to $\sim$30 Mm and initiate the eruption of MFR3. Ultimately, MFR1's eruption results in an M3.4-class flare and a CME, while MFR2 and MFR3 collectively produce an M9.8-class flare and another halo CME. This study shows the slipping process in a multi-MFR system, showing how one MFR's slipping can trigger the eruption of another MFR. We propose that the CME--CME interactions caused by multiple MFR eruptions may contribute to the significant geoeffectiveness

A modified ‘skeleton/skin’ strategy for designing CoNiP nanosheets arrayed on graphene foam for on/off switching of NaBH4_{4} hydrolysis

CoNiP nanosheet array catalysts were successfully prepared on three-dimensional (3D) graphene foam using hydrothermal synthesis. These catalysts were prepared using 3D Ni–graphene foam (Ni/GF), comprising nickel foam as the ‘skeleton’ and reduced graphene oxide as the ‘skin’. This unique continuous modified ‘skeleton/skin’ structure ensure that the catalysts had a large surface area, excellent conductivity, and sufficient surface functional groups, which promoted in situ CoNiP growth, while also optimizing the hydrolysis of sodium borohydride. The nanosheet arrays were fully characterized and showed excellent catalytic performance, as supported by density functional theory calculations. The hydrogen generation rate and activation energy are 6681.34 mL min$_{−1}$ g$_{−1}$ and 31.2 kJ mol$_{−1}$, respectively, outperforming most reported cobalt-based catalysts and other precious metal catalysts. Furthermore, the stability of mockstrawberry-like CoNiP catalyst was investigated, with 74.9% of the initial hydrogen generation rate remaining after 15 cycles. The catalytic properties, durability, and stability of the catalyst were better than those of other catalysts reported previously

Detection of Pneumocystis jirovecii and Toxoplasma gondii in patients with lung infections by a duplex qPCR assay

Pneumocystis pneumonia (PCP) and pulmonary toxoplasmosis (PT) are caused by Pneumocystis jirovecii and Toxoplasma gondii. The clinical symptoms and imaging of PCP and PT are indistinguishable. A duplex qPCR was developed to differentiate between these two pathogens. In testing 92 clinical samples to validate the performance of this method for P. jirovecii detection, it identified 31 positive samples for P. jirovecii infection, consistent with clinical diagnosis. Among the remainder of the 61 clinical samples with suspected PCP, yet showing as negative by the conventional PCR diagnosis approach, 6 of them proved positive using our new assay. Our new approach also produced similar results in identification of T. gondii infections, giving a result of 2 positive and 20 negative in clinical samples. An investigation was undertaken on the prevalence of P. jirovecii and T. gondii infections using 113 samples from lung infection patients. 9% (10/113) were shown to be positive with infections of P. jirovecii, 2% with T. gondii (2/113) and 5% (6/113) were co-infected with both pathogens. Although this duplex qPCR can detect individual P. jirovecii and T. gondii infection, and co-infection of both pathogens, further large-scale investigations are needed to validate its performance, especially in T. gondii detection. Our assay provides a rapid and accurate tool for PCP and PT diagnosis in immunocompromised population and clinical surveillance of these infections in patients with no immune defects

Common susceptibility variants are shared between schizophrenia and psoriasis in the Han Chinese population

Previous studies have shown that individuals with schizophrenia have a greater risk for psoriasis than a typical person. This suggests that there might be a shared genetic etiology between the 2 conditions. We aimed to characterize the potential shared genetic susceptibility between schizophrenia and psoriasis using genome-wide marker genotype data