Tungstate-Based Inorganic−Organic Hybrid Nanobelts/Nanotubes with Lamellar Mesostructures: Synthesis, Characterization, and Formation Mechanism

The formation process of novel tungstate-based inorganic−organic hybrid nanobelts/nanotubes with lamellar mesostructures has been investigated, with an emphasis on monitoring the morphological and microstructural changes of the products during the reactions of H2W2O7·xH2O (x = 3.49) with n-alkylamines (CmH2m+1NH2, 4 ≤ m ≤ 14) in a system of heptane/n-alkylamine/H2W2O7·xH2O (n-alkylamine:H2W2O7·xH2O molar ratio of about 30) under ambient conditions. The results indicate that normal intercalation occurrs in the early stage to form intercalation compounds with double-octahedral W−O layers, which are then dissolved in the highly alkaline aqueous solutions confined in the reverse-micelle-like media, where the dissolved species recrystallize to form hybrid nanobelts/nanotubes with single-octahedral W−O layers. Both the intercalation compounds obtained after a short reaction time (e.g., 30 min) and the hybrid nanobelts/nanotubers formed after a long reaction time (e.g., 5 days) possess a bilayered arrangement of n-alkyl chains, but their tilt angle in the intercalation compounds (42°) is much smaller than that in the hybrid nanobelts/nanotubes (71°). The interlayer water released from H2W2O7·xH2O upon intercalation of n-alkylamine reacts with excess n-alkylamine molecules to form highly alkaline aqueous solutions, which have vital effects on the subsequent dissolution of the double-octahedral W−O layers to be single-octahedral layers. In addition, the high molar n-alkylamine:H2W2O7·xH2O ratios (e.g., 30) are necessary to form tungstate-based inorganic−organic nanobelts/nanotubes, and the nonpolar solvents not only facilitate the reactions between n-alkylamines and H2W2O7·xH2O but also favor the formation of belt/tubelike morphology

High Coordination Numbers of Actinides (An) in AnC₁₃⁺ Rings (An = Th and U)

An intriguingly high abundance of both ThC13+ and UC13+ cluster cations was observed in a previous mass spectrometry experiment; however, the structural identification of these cations has not yet been completed. In this study, we determined the lowest lying structures of ThC13+ and UC13+ clusters using an unbiased structural search method. The 13-coordinate planar ring configuration was the most stable for both ThC13+ and UC13+ cluster cations. The C–An bonds in ThC13+ and UC13+ show a small degree of covalency, originating from the overlap of the s, d, and f orbitals of the An atoms with C 2p orbitals of both π and σ characteristics. The infrared and electronic absorption spectra of the most favorable planar ring configurations were theoretically simulated to facilitate the identification of the molecular structures in future experiments. This study provides an in-depth understanding of the experimental mass spectra

DataSheet1_Thermodynamics-Based Model Construction for the Accurate Prediction of Molecular Properties From Partition Coefficients.docx

Developing models for predicting molecular properties of organic compounds is imperative for drug development and environmental safety; however, development of such models that have high predictive power and are independent of the compounds used is challenging. To overcome the challenges, we used a thermodynamics-based theoretical derivation to construct models for accurately predicting molecular properties. The free energy change that determines a property equals the sum of the free energy changes (ΔGFs) caused by the factors affecting the property. By developing or selecting molecular descriptors that are directly proportional to ΔGFs, we built a general linear free energy relationship (LFER) for predicting the property with the molecular descriptors as predictive variables. The LFER can be used to construct models for predicting various specific properties from partition coefficients. Validations show that the models constructed according to the LFER have high predictive power and their performance is independent of the compounds used, including the models for the properties having little correlation with partition coefficients. The findings in this study are highly useful for applications in drug development and environmental safety.</p

Structures, Stabilities, and Spectral Properties of Endohedral Borospherenes M@B₄₀^0/– (M = H₂, HF, and H₂O)

The discovery of borospherene B40 leads to a new beginning for the study of boron chemistry and may lead to new boron-based nanomaterials. Based on density functional theory, the structures, electronic properties, infrared and Raman spectra, photoelectron spectra, and electronic absorption spectra of endohedral borospherenes M@B400/– (M = H2, HF, and H2O) are investigated. It is found that H2, HF, and H2O monomers can form stable endohedral borospherenes M@B400/– (M = H2, HF, and H2O). In addition, the calculated results indicate that the doped molecule at the off-center location can relax to the center location within the cage and the symcenter of the doped molecule is almost located in the center of the cage. Unlike endohedral metalloborospherene Ca@B40, which is a charge-transfer complex between Ca2+ and B402–, natural population analyses and chemical bonding analyses reveal that there is no significant charge transfer of the doped molecule. The calculated spectra indicate that doping of a molecule (H2, HF, or H2O) in borospherene B40 can change the photoelectron spectra and doping of a polar molecule (HF or H2O) in borospherene B40 can change the spectral properties. For instance, the addition of a molecule can increase infrared and Raman-active modes and cause a red shift or blue shift of electronic spectra. These spectral features can be compared with future experimental values of endohedral borospherenes M@B400/– (M = H2, HF, and H2O)

DataSheet1_Co-Ni Basic Carbonate Nanowire/Carbon Nanotube Network With High Electrochemical Capacitive Performance via Electrochemical Conversion.PDF

In this work, the Co-Ni basic carbonate nanowires were in-situ grown on carbon nanotube (CNT) network through a facile chemical bath deposition method, which could be further converted into active hydroxide via cyclic voltammetry strategy. A series of carbonate nanowire/nanotube with different Co/Ni ratio revealed the different growth status of the nanowires on CNT network. The nanostructures of the as-synthesized samples were examined via powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) techniques. The Co/Ni ratio of the carbonate largely affected the size of the nanowires, that the low Co/Ni ratio was beneficial for thin nanowire formation and the nanowires loading on CNT network. Subsequently, the electrochemical performance of the Co-Ni basic hydroxides was studied in a three-electrode test system. The nanowires with low Co/Ni ratio 1/2 can form nanowire array on individual CNTs, which exhibited better electrochemical capacitive performance than the composite network with high Co/Ni ratio nanowires after electrochemical activation. The addition of Co enhanced the rate performance of the hydroxide/CNT, especially improved the long cycle stability largely compared to the rate performance of pure Ni converted hydroxide/CNT composite film reported by our previous research. This result is valuable for the design of inorganic electrochemical active composites based on conductive networks for energy conversion/storage applications.</p

DataSheet1_Contribution of vanishing mountain glaciers to global and regional terrestrial water storage changes.DOCX

Mountain is called the water towers of the world. Due to high sensitivity and vulnerability to climate change, more attention is paid to the change of water resources in mountain regions, where provide water for environmental and human demands downstream. Mountains glacier, as one of the most important components of terrestrial water storage (TWS), effectively regulates and stabilizes surface water resources. TWS appears to be trending below previous ranges in recent years, and glacier retreating is becoming the primary cause of TWS depletion in mountain regions. However, how much mountain glacier changes contribute to TWS changes around mountain regions is unknown. Here, we combine multi-source datasets to quantify the contribution rate over high-elevation mountain regions. On a global scale, the glacial melting is equivalent to about 49% of the total TWS decline during 2006–2015. TWS and glacier show decreasing trends in most of mountain regions and watersheds of the Third Pole and surroundings (TPs), but the contribution ranges from −23% to 728% in mountain regions and −21% to 99% in watersheds of TPs. There are larger contributions in regions with more glaciers, while smaller in less glacier-covered regions. Glacier together with other storage components play diverse roles across different mountain regions and watersheds, but factors with great influence are glacier, groundwater, soil water, reservoirs and lakes.</p

BaTiF₆:Mn⁴⁺ Red Phosphor: Synthesis of Single Crystals at Room Temperature and the High Hydrolysis-Resistant Property

Due to the low solubility of BaF2, the BaTiF6:Mn4+ phosphor for whitelight-emitting diodes application has been generally synthesized by the hydrothermal route, during which process the valence of the manganese dopant is difficult to be controlled as tetravalent. In this paper, a new synthesis method that proceeded at room temperature was reported. This method uses BaTiOF4 as the precursor and allows for the control of the phase transformation rate from BaTiOF4 to BaTiF6 in the K2MnF6/HF acid solution. Benefitting from that, we successfully prepared red-emitting BaTiF6:Mn4+ elongated crystals with a single-crystal nature up to a record-breaking length of 200–300 μm. The effects of the crystallinity of the BaTiOF4 precursor on its phase transformation rate into BaTiF6 and on the optimal Mn4+ doping concentration were studied. The BaTiF6:Mn4+ single-crystal phosphor exhibits relatively excellent hydrolysis-resistant behavior after being immersed in water for 3 h, at which condition the commercial K2SiF6:Mn4+ has become brown. This study may inspire the room-temperature preparation of other hydrolysis-resistant alkali earth fluorotitanate or fluorosilicate phosphors with stable tetravalent manganese doping

Population structure of Han population in China revealed by 41 STR loci

Background: Currently, the Han population in China may be comprised of different genetic groups due to geographic, cultural and economic factors. Understanding population structure is very important for forensic purposes. However, knowledge of the genetic substructure within the whole Han population in China is still limited. Aim: This study is designed to ascertain the genetic structure of the Han population in China through genetic data from autosomal short tandem repeats (STRs). Subjects and methods: A set of 41 STR markers were analysed in 8725 unrelated Han Chinese males from the seven geographic regions of Northeast, North, East, Central, South, Southwest and Northwest in mainland China. Allele frequencies and F-statistics were estimated. Principal coordinate analysis (PCoA), phylogenetic analyses, analysis of molecular variance (AMOVA) and discriminant analysis of principal components (DAPC) were performed to explore the population structure. Results: Rare alleles that have not been observed in previous samples were detected. The small overall Fst values (0.0008), AMOVA and DAPC indicated that there is no population structure in Han Chinese. However, the PCoA and phylogenetic tree disclose a genetic differentiation pattern from north to south. Conclusions: There is no apparent population substructure in the Han population in China. However, genetic distances among the Han populations correlate with geographic locations.</p

DataSheet1_Decadal variability of precipitation over the Tibetan Plateau modulated by the 11-year solar cycle over the past millennium.docx

Introduction: Knowledge of precipitation over the Tibetan Plateau, often referred to as the “Asian water tower”, is crucial for water resource management, infrastructure planning, and disaster mitigation. However, the decadal variability of Tibetan Plateau precipitation in response to the 11-year solar cycle remains unknown.Methods: Here, we used observational data obtained between 1901 and 2013, together with proxy-based reconstructions of the past five centuries, and discovered a notable summer wet condition over the central‒southern Tibetan Plateau, accompanied by a dry condition over the southeastern Tibetan Plateau, during peaks in the 11-year solar cycle. Using an ensemble mean of four solar-only sensitivity experiments from the Community Earth System Model Last Millennium Ensemble (CESM‒LME), we further demonstrated that the 11-year solar cycle can induce this anomalous pattern of a wet central‒southern and dry southeastern Tibetan Plateau.Results and discussion: The modeling results indicated that, under a solar maximum, a substantial surface warming occurs over the Asian continent, especially the Tibetan Plateau region; this causes an anomalous Tibetan Plateau–Indian Ocean thermal contrast, which enhances the Indian summer monsoon. The additional Tibetan Plateau heating also enhances and causes a northward shift of the South Asian High, which further intensifies the Indian summer monsoon. The enhanced Indian summer monsoon transports water vapor to the northern Indian continent, which rises upon reaching the central‒southern Tibetan Plateau, substantially increasing precipitation. Meanwhile, a negative Pacific Decadal Oscillation-like sea surface temperature pattern occurs under a solar maximum, leading to a large-scale anticyclonic anomaly over the Yangtze River basin, southeastern Tibetan Plateau, and southern Japan, substantially decreasing precipitation in these regions.</p

Global gridded AHF for 2050 (30 arc-second)

This data shows the spatial distribution of the annual mean anthropogenic heat flux (AHF) for 2050 in the world. Spatial resolution of this data is 30 arc-second