Ural Branch of the Russian Academy of Sciences

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.

The asteroid impact near the Russian city of Chelyabinsk on 15 February 2013 was the largest airburst on Earth since the 1908 Tunguska event, causing a natural disaster in an area with a population exceeding one million. Because it occurred in an era with modern consumer electronics, field sensors, and laboratory techniques, unprecedented measurements were made of the impact event and the meteoroid that caused it. Here, we document the account of what happened, as understood now, using comprehensive data obtained from astronomy, planetary science, geophysics, meteorology, meteoritics, and cosmochemistry and from social science surveys. A good understanding of the Chelyabinsk incident provides an opportunity to calibrate the event, with implications for the study of near-Earth objects and developing hazard mitigation strategies for planetary protection.

Crude oil and petroleum products are widespread water and soil pollutants resulting from marine and terrestrial spillages. International statistics of oil spill sizes for all incidents indicate that the majority of oil spills are small (less than 7 tonnes). The major accidents that happen in the oil industry contribute only a small fraction of the total oil which enters the environment. However, the nature of accidental releases is that they highly pollute small areas and have the potential to devastate the biota locally. There are several routes by which oil can get back to humans from accidental spills, e.g. through accumulation in fish and shellfish, through consumption of contaminated groundwater. Although advances have been made in the prevention of accidents, this does not apply in all countries, and by the random nature of oil spill events, total prevention is not feasible. Therefore, considerable world-wide effort has gone into strategies for minimising accidental spills and the design of new remedial technologies. This paper summarizes new knowledge as well as research and technology gaps essential for developing appropriate decision-making tools in actual spill scenarios. Since oil exploration is being driven into deeper waters and more remote, fragile environments, the risk of future accidents becomes much higher. The innovative safety and accident prevention approaches summarized in this paper are currently important for a range of stakeholders, including the oil industry, the scientific community and the public. Ultimately an integrated approach to prevention and remediation that accelerates an early warning protocol in the event of a spill would get the most appropriate technology selected and implemented as early as possible - the first few hours after a spill are crucial to the outcome of the remedial effort. A particular focus is made on bioremediation as environmentally harmless, cost-effective and relatively inexpensive technology. Greater penetration into the remedial technologies market depends on the harmonization of environment legislation and the application of modern laboratory techniques, e.g. ecogenomics, to improve the predictability of bioremediation.

Remote sensing is revolutionizing the way we study forests, and recent technological advances mean we are now able - for the first time - to identify and measure the crown dimensions of individual trees from airborne imagery. Yet to make full use of these data for quantifying forest carbon stocks and dynamics, a new generation of allometric tools which have tree height and crown size at their centre are needed. Here, we compile a global database of 108753 trees for which stem diameter, height and crown diameter have all been measured, including 2395 trees harvested to measure aboveground biomass. Using this database, we develop general allometric models for estimating both the diameter and aboveground biomass of trees from attributes which can be remotely sensed - specifically height and crown diameter. We show that tree height and crown diameter jointly quantify the aboveground biomass of individual trees and find that a single equation predicts stem diameter from these two variables across the world's forests. These new allometric models provide an intuitive way of integrating remote sensing imagery into large-scale forest monitoring programmes and will be of key importance for parameterizing the next generation of dynamic vegetation models.

We compiled a global database for leaf, stem and root biomass representing c. 11 000 records for c. 1200 herbaceous and woody species grown under either controlled or field conditions. We used this data set to analyse allometric relationships and fractional biomass distribution to leaves, stems and roots. We tested whether allometric scaling exponents are generally constant across plant sizes as predicted by metabolic scaling theory, or whether instead they change dynamically with plant size. We also quantified interspecific variation in biomass distribution among plant families and functional groups. Across all species combined, leaf vs stem and leaf vs root scaling exponents decreased from c. 1.00 for small plants to c. 0.60 for the largest trees considered. Evergreens had substantially higher leaf mass fractions (LMFs) than deciduous species, whereas graminoids maintained higher root mass fractions (RMFs) than eudicotyledonous herbs. These patterns do not support the hypothesis of fixed allometric exponents. Rather, continuous shifts in allometric exponents with plant size during ontogeny and evolution are the norm. Across seed plants, variation in biomass distribution among species is related more to function than phylogeny. We propose that the higher LMF of evergreens at least partly compensates for their relatively low leaf area : leaf mass ratio.

Impedance measurements indicate that Na2B12H12 exhibits dramatic Na(+) conductivity (on the order of 0.1 S cm(-1)) above its order-disorder phase-transition at ≈529 K, rivaling that of current, solid-state, ceramic-based, Na-battery electrolytes. Superionicity may be aided by the large size, quasispherical shape, and high rotational mobility of the B12H12(2-) anions.

Fossil pollen data supplemented by tree macrofossil records were used to reconstruct the vegetation of the Former Soviet Union and Mongolia at 6000 years. Pollen spectra were assigned to biomes using the plant‐functional‐type method developed by Prentice et al . (1996). Surface pollen data and a modern vegetation map provided a test of the method. This is the first time such a broad‐scale vegetation reconstruction for the greater part of northern Eurasia has been attempted with objective techniques. The new results confirm previous regional palaeoenvironmental studies of the mid‐Holocene while providing a comprehensive synopsis and firmer conclusions. West of the Ural Mountains temperate deciduous forest extended both northward and southward from its modern range. The northern limits of cool mixed and cool conifer forests were also further north than present. Taiga was reduced in European Russia, but was extended into Yakutia where now there is cold deciduous forest. The northern limit of taiga was extended (as shown by increased Picea pollen percentages, and by tree macrofossil records north of the present‐day forest limit) but tundra was still present in north‐eastern Siberia. The boundary between forest and steppe in the continental interior did not shift substantially, and dry conditions similar to present existed in western Mongolia and north of the Aral Sea.

The crystal structures of the tungsten monocarbide δ-WC and the disordered lower carbide β-W2C are studied. Using magnetic susceptibility measurements, the hexagonal carbide δ-WC is shown to be stable from 300 to 1200 K. The sequence of phase transformations associated with β-W2C ordering is analyzed. The temperature and composition stability limits of the cubic carbide γ-WC1−x are evaluated, and the first data are presented on the variation of its lattice parameter with composition. An optimized W-C phase diagram is proposed which takes into account detailed structural and phase-equilibrium data for tungsten carbides.

The article presents a Web-based platform for collecting and storing toxicological structural alerts from literature and for virtual screening of chemical libraries to flag potentially toxic chemicals and compounds that can cause adverse side effects. An alert is uniquely identified by a SMARTS template, a toxicological endpoint, and a publication where the alert was described. Additionally, the system allows storing complementary information such as name, comments, and mechanism of action, as well as other data. Most importantly, the platform can be easily used for fast virtual screening of large chemical datasets, focused libraries, or newly designed compounds against the toxicological alerts, providing a detailed profile of the chemicals grouped by structural alerts and endpoints. Such a facility can be used for decision making regarding whether a compound should be tested experimentally, validated with available QSAR models, or eliminated from consideration altogether. The alert-based screening can also be helpful for an easier interpretation of more complex QSAR models. The system is publicly accessible and tightly integrated with the Online Chemical Modeling Environment (OCHEM, http://ochem.eu). The system is open and expandable: any registered OCHEM user can introduce new alerts, browse, edit alerts introduced by other users, and virtually screen his/her data sets against all or selected alerts. The user sets being passed through the structural alerts can be used at OCHEM for other typical tasks: exporting in a wide variety of formats, development of QSAR models, additional filtering by other criteria, etc. The database already contains almost 600 structural alerts for such endpoints as mutagenicity, carcinogenicity, skin sensitization, compounds that undergo metabolic activation, and compounds that form reactive metabolites and, thus, can cause adverse reactions. The ToxAlerts platform is accessible on the Web at http://ochem.eu/alerts, and it is constantly growing.

Na2B10H10 exhibits exceptional superionic conductivity above ca. 360 K (e.g., ca. 0.01 S cm−1 at 383 K) concomitant with its transition from an ordered monoclinic structure to a face-centered-cubic arrangement of orientationally disordered B10H102− anions harboring a vacancy-rich Na+ cation sublattice. This discovery represents a major advancement for solid-state Na+ fast-ion conduction at technologically relevant device temperatures. Recently, complex hydride salts undergoing solid-state, entropy-driven, order–disorder transitions have been shown to exhibit impressive fast-ion conduction properties as a result of the appearance of vacancy-rich cation sublattices within networks of highly mobile, reorientationally disordered polyanions.1 Initial interest has mainly focused on the light-metal Li and Na salts possessing tetrahydroborate (BH4−) polyanions (see Figure 1), such as LiBH4 and Na2BH4NH2, as well as related derivative materials.2-5 Very recently, it was discovered that Li and Na salts possessing the larger icosahedral dodecahydro-closo-dodecaborate (B12H122−) anions (see Figure 1) also undergo order–disorder phase transitions,6, 7 with Na2B12H12 exhibiting disorder-induced superionic conductivity (approaching 0.1 S cm−1) above around 480 K.8 This conductivity rivals that of traditional ceramic materials, Na β”-alumina solid electrolyte (BASE), and Na superionic conductor (NASICON), as well as more recent Na3PS4-based glass ceramic electrolytes, all currently of considerable interest for use in Na-ion batteries.9-11 The pronounced superionicity and relatively low conduction barrier for disordered Na2B12H12 are probably due, in part, to the larger size (and roughly spherical shape) of the B12H122− anions compared with the substantially smaller BH4− anions (see Figure 1) present in other investigated fast-ion conductors.1 These types of large polyanion compounds represent a potentially fertile area for discovering new materials with superionic conductivities, but with lower transition temperatures. Here we report our finding that sodium decahydro-closo-decaborate (Na2B10H10), a related sodium salt containing large, ellipsoidal-shaped, B10H102− anions (see Figure 1), forms a disordered, face-centered-cubic (fcc) phase above ca. 360 K, possessing a vacancy-rich Na+ cation sublattice. This cation sublattice is highly mobile within the spacious corridors formed by the large B10H102− anions and exhibits remarkable superionic conductivity (e.g., σ ≈ 0.01 S cm−1 at 383 K) to substantially lower temperatures than for Na2B12H12. This conductivity is more than an order of magnitude higher than that of all other solid-state Na-based complex-hydride materials investigated to date in this temperature region.1 As such, this discovery represents a major advancement in the field of solid-state Na+ fast-ion conduction at technologically relevant device temperatures. Figure 2 shows differential scanning calorimetry (DSC) results for Na2B10H10 after several heating/cooling cycles. There is a clear reversible transition, first observed by Bonnetot et al.,12 with minor hysteresis. After a number of cycles to 500 K, the hysteresis decreases and the onset temperature stabilizes near 360 K upon both heating and cooling. A slow attenuation of the DSC features begins to occur upon repeated cycling to temperatures near 600 K. Figure 3 shows the neutron powder diffraction (NPD) result for a partially deuterated Na211B10H10 sample at 410 K, above the phase transition. Table S1 in the Supporting Information lists the corresponding structural parameters. The Rietveld-refined model confirms transformation from the known, low-T, ordered monoclinic structure13 (not shown) to a high-T disordered structure with Na+ cations partially occupying a variety of interstitial sites within an fcc lattice of orientationally disordered anions. Neutron-scattering Fourier difference maps initially suggested that the broad distribution of cation positions and the inclusion of the three most intense positions were ultimately necessary to attain a good model fit to the data. Furthermore, the refinements suggested extensive anion orientational disorder, which could be represented in various ways via multiple B and H positions. The model reflects the simplest representation of six approximately superimposed anion orientations, each equally probable. In particular, the six possible anion orientations are aligned in pairs with their long axes oriented along any one of the three orthogonal crystallographic axes. The members of each pair are azimuthally offset from each other by 45° about their long axes. Each B and H position in the structure is 1/3 occupied, being shared by two of the six possible orientations. Anion dynamical behavior was probed by neutron elastic-scattering fixed-window scans (FWSs)14 of Na211B10H10. The results in Figure 4 suggest that a dramatic change in B10H102− anion reorientational mobility occurs upon phase transformation. In particular, the high elastic neutron counts in the low-T ordered phase suggest anion reorientational jump frequencies less than 108 s−1, whereas the roughly 80% lower counts in the high-T disordered phase suggest an orders-of-magnitude enhancement in jump frequencies to greater than 1010 s−1. This is reminiscent of the FWS behavior observed for Na2B12H12.7, 15 Indeed, the inset in Figure 4 showing a quasielastic neutron scattering (QENS) spectrum for the disordered phase at 375 K indicates a quasielastic component with a Lorentzian linewidth of about 41(1) μeV FWHM, which reflects a jump correlation frequency on the order of 3 × 1010 s−1. The ratio of elastic and total scattering intensities (which is also consistent with the ratio of FWS neutron counts in the disordered and ordered phases from Figure 4) suggests that, besides the B10H102− reorientational jumps around the long axis, two-fold anion flips leading to exchanges of apical H atom positions are also occurring. We also probed the Na+ dynamical behavior in Na2B10H10 by 23Na NMR measurements. Figure 5 shows the 23Na spin-lattice relaxation rate R1 at the resonance frequency of ω/2π = 23 MHz as a function of T−1. The general features of the behavior of R1 for Na2B10H10 resemble those for Na2B12H12 at the phase transition.16 Here, R1 exhibits a jump accompanied by a change in sign of its temperature dependence. Such behavior indicates that the transition from the ordered to the disordered phase is accompanied by an abrupt increase in the Na+ jump rate τd−1. The expected R1(T) maximum is ‘folded’; i.e., because of the abrupt increase in τd−1 at the phase transition, there is a jump directly from the low-T slope to the high-T slope of the R1(T) peak. On the low-T slope, R1 is proportional to τd−1; on the high-T slope, R1 is proportional to τd. From the two slopes, we obtain activation energies for Na+ jumps in the ordered and disordered phases of 750(20) meV and 190(10) meV, respectively. Although we cannot reliably determine the absolute values of τd−1 due to the ‘folded’ nature of the R1(T) peak, the data do allow us to conclude that the Na+ jump rate exceeds ω ≈ 1.5 × 108 s−1 just above the phase transition. Moreover, the very small 23Na NMR linewidth (0.2 kHz full-width half-maximum (FWHM)) observed in the disordered phase confirms that the Na+ cations are undergoing long-range diffusion. To characterize the Na2B10H10 conduction behavior, we carried out AC impedance measurements between 295 K and 423 K using a pressed disk of polycrystalline Na2B10H10 powder with either gold or (similarly performing) molybdenum foil contacts. Cross-sectional SEM images of the pelletized sample in Figure S1 of the Supporting Information confirm that intimate contacts among the particles were achieved. Na2B10H10 can be easily pelletized without further sintering, as has been reported for LiBH4 and other complex hydrides.1,5 The results are shown in Figure 6 for the gold contacts. The inset shows typical complex impedance plots at various temperatures. They consist of an arc in the high-frequency region and a spike in the low-frequency region due to contributions from the bulk/grain boundaries and the electrode, respectively. The results suggest that Na2B10H10, similar to Na2B12H12,8 behaves like a typical ionic conductor. The temperature dependence of the conductivity indicates dramatic superionic conductivity above the hysteretic order–disorder transition near 373 K, rising two orders of magnitude higher than that in the low-T phase. This behavior is superior to that of other investigated complex hydride materials. Indeed, the conductivity exhibits a value of about 0.01 S cm−1 at 383 K, which is about 25× greater than that of Na2BH4NH2 (4 × 10−4 S cm−1).4 A conductivity above 0.1 S cm−1 at 500 K is suggested by extrapolation of the lower-T data. The activation energy for conduction is evaluated to be 0.47 eV, which is higher than that reported for Na2B12H12 (0.21 eV)8 but lower than those reported for Na2BH4NH2 (0.61 eV)4, 8 and the high-T phase of LiBH4 (0.53 eV).2 Nevertheless, any rationalization of the differences based solely on anion size is complicated by the substantial differences in structure and conduction pathways. It should be noted that the NMR-derived activation energies discussed above reflect the average microscopic barriers for all cation diffusional jumps between neighboring sites within the Na2B10H10 lattice, some of which may have little effect on the macroscopic conductivity barrier. In contrast, the latter barrier is more reflective of an overall rate-limiting step, such as a particular type of cation jump within the material required to maintain conduction pathways or cation transport, e.g., across grain boundaries (although such grain-boundary bottlenecks are believed to be small in the present system). The superionic conductivity of disordered Na2B10H10 is consistent with the relatively small activation energy for Na+ diffusion within the liquid-like cation sublattice. Again, similar to disordered Na2B12H12,8 the overly large size and spheroidal shape of the polyanions result in less restrictive interstitial pathways and, hence, reduced Na+ diffusional bottlenecks between the various cation sites within the close-packed anion sublattice. As for the other disordered complex hydrides, the reorientationally mobile anions associated with superionic Na2B10H10 may also lower the cation diffusional barrier by providing a dynamically cooperative environment for cation jumps within the voids of the anion sublattice. Indeed, at least an order-of-magnitude-higher anion reorientational jump rate compared with the Na+ diffusional jump rate provides a dynamic environment where the anions can behave as ‘lubricants’ for cation diffusive motions. A comparison of the relative sizes of the B10H102− and B12H122− anions in Figure 1 indicates a similar maximum dimension for each anion. In fact, the lattice constants for the disordered fcc Na2B10H10 and body-centered cubic (bcc) Na2B12H12 structures7 indicate that both disordered anions possess similar spherical packing radii of ≈3.5 Å. This makes the small 190 meV activation energy for Na+ diffusion in Na2B10H10 particularly noteworthy, since it is less than half that of Na2B12H12 (410 meV).16 Such a difference may be the result of the different natures of the diffusion saddle points inherent within the fcc and bcc structures, but may also signal a local geometric advantage that the less-spherical B10H102− anions have over their more spherical relatives. In particular, within a cubic structure, one might expect each of the more-ellipsoidal B10H102− anions to take up slightly less space in directions perpendicular to their long axes than the more spherical B12H122− anions. On a local level, this would allow more free space between anions for cation diffusion. The QENS results are consistent with a locally ellipsoidal anion, by suggesting that each anion retains a particular orientation of its long axis over at least a nanosecond timescale. Much needs to be done to provide a better understanding of the superionic properties of this new class of conducting materials. For example, since Na2B10H10 possesses a much lower order–disorder phase-transition temperature than Na2B12H12, one might think that the lighter-metal analogue, Li2B10H10, would also possess a lower order–disorder phase-transition temperature than Li2B12H12,6, 7 thus enhancing the stability of the disordered, fast-ion-conducting structure. Our Li2B10H10 DSC measurements suggest the contrary. Rather, Li2B10H10 appears to possess a slightly higher transition temperature than Li2B12H12 does, leading to an unstable disordered structure, which makes it unsuitable as a solid-state, Li+-conducting electrolyte. However, the addition of other anions or cations to Li2B10H10 and to Na2B10H10 may lead to hybrid materials displaying even lower transition temperatures than seen here for pure Na2B10H10. We are currently pursuing such potentially favorable modifications. For all these disordered materials, a more thorough understanding of the relationship of structural disorder and anion reorientational mobility to cation diffusion and conductivity will benefit from future first-principles molecular-dynamics calculations,1, 17, 18 which may in turn lead to a more rational pathway to develop improved modified materials. In conclusion, the discovery of very high superionic conductivity in Na2B10H10 that persists to temperatures as low as 360 K is a marked improvement over Na2B12H12 and other complex hydrides. Although hygroscopic, Na2B10H10 remains air-stable at room temperature with no noticeable degradation in its diffraction pattern up to at least 500 K. DSC indicates that the compound decomposes/polymerizes with some mass loss of presumably H2 at around 850 K. Preliminary cyclic voltammetry measurements indicate that ordered Na2B10H10 is electrochemically stable up to at least 4 V at 353 K and disordered Na2B10H10 up to at least 5 V at 393 K (see Figure S2 in the Supporting Information). Its favorable properties and high conductivity warrant a serious investigation of Na2B10H10's applicability to next-generation solid-state Na-ion battery technologies. Based on these results, successful future searches for related materials with even better cation conductivity properties may be enhanced by the inclusion of similar- or even larger-sized polyanions compared with B10H102−. Synthesis: 11Boron-enriched Na211B10H10 (and partially deuterated Na211B10H10) was synthesized as follows: the triethylammonium salt (Et3NH)2[11B10H10] was synthesized via reaction of 11B10H14 (Katchem19 and triethylamine in para-xylene at reflux. The crude product was recrystallized from water/EtOH and dried in vacuum (10 mTorr) at room temperature for 16 h. The (Et3NH)2[11B10H10] was then converted into the corresponding acid (H3O)2[11B10H10] by ion exchange using an Amberlite resin in H+-form. Aqueous Na211B10H10 was prepared by neutralization of (H3O)2[11B10H10] with 0.1 m NaOH until a pH value of 7 was reached. The solvent was removed on a rotary evaporator at 323 K. Unlabeled Na2B10H10 was synthesized using a similar approach. The resulting hydrated materials were dried under vacuum at 433 K for 16 h. For the partially deuterated sample, a single exchange treatment was performed by dissolution and stirring for 3 h of 1 g of Na211B10H10 in 20 mL of D2O slightly acidified by adding 50 μL of a saturated solution of deuterochloric (DCl) acid in D2O. The resulting dried sample had a D:H ratio of only 27:73 as determined from refinement of the 20 K NPD pattern, yet led to some reduction of the incoherent neutron scattering background from the lighter H isotope. Measurement Details: DSC measurements were made with a Netzsch (STA 449 F1 Jupiter) TGA-DSC under He flow with Al sample pans. The neutron-scattering measurements were performed at the National Institute of Standards and Technology Center for Neutron Research. NPD patterns were measured on the BT-1 High-Resolution Powder Diffractometer using the Ge(311) monochromator at a neutron wavelength of 2.077 Å. Horizontal divergences of 60′, 20′, and 7′ of arc were used for the in-pile, monochromatic-beam, and diffracted-beam collimators, respectively. The sample was contained in a 6 mm-diameter V can inside a He closed-cycle refrigerator. FWSs were measured on the High-Flux Backscattering Spectrometer using 6.27 Å wavelength neutrons, with a resolution of 0.8 μeV FWHM. QENS spectra were collected at 270 K (resolution measurement) and 375 K on the Disk Chopper Spectrometer using 4.08 Å wavelength neutrons with a resolution of 79 μeV FWHM. 23Na NMR measurements were performed on the pulse spectrometer described earlier16 at the frequency ω/2π = 23 MHz. The nuclear spin–lattice relaxation rates were measured using the saturation–recovery method. NMR spectra were recorded by Fourier transforming the solid-echo signals. Ionic conductivities were determined in heating and cooling runs repeatedly in the temperature range between 303 K and 423 K by the AC complex-impedance method using an NF FRA5097 frequency response analyzer over a frequency range of 10 Hz to 10 MHz. All the measurements were performed under Ar. The powder sample was pressed into a pellet of 8 mm in diameter and 2 mm in thickness without sintering. The pellet density was about 1.17 g cm−3, which is more than 95% of the density calculated from the lattice parameters. Au or Mo foils were used as electrodes and were mechanically fixed on both faces of the pellet. The resistances of the sample were obtained by least-square fittings of a single arc in the high-frequency range using equivalent circuits of a parallel combination of a resistance and a capacitance. At high temperature, since only a spike caused by the electrode contribution was observed, the resistance values were calculated from the intercept of the spike. The cross-section of the pelletized sample was examined by scanning electron microscopy (SEM) (JEOL JSM6009). Cyclic voltammetry measurements were conducted at scan rates of 5 mV s−1 using a potentiostat/galvanostat (Princeton VersaSTAT4) with a Mo disk as the working electrode and counter/reference electrodes of Na or Na–In at 353 K and 393 K, respectively. Finally, for all the figures, standard uncertainties are commensurate with the observed scatter in the data, if not explicitly designated by the vertical error bars. This work was performed, in part, in collaboration between members of IEA HIA Task 32-Hydrogen-based Energy Storage. The authors gratefully acknowledge support from DOE EERE through Grant Nos. DE-EE0002978 and DE-AC04–94AL85000; the Russian Foundation for Basic Research under Grant No. 12–03–00078; the U.S. Civilian Research & Development Foundation (CRDF Global) under Award No. RUP1–7076-EK-12; the National Science Foundation (NSF) under Cooperative Agreement No. OISE-9531011; the Integrated Materials Research Center for the Low-Carbon Society (LC-IMR), Tohoku University; the Advanced Low Carbon Technology Research and Development Program (ALCA) from the Japan Science and Technology Agency (JST); and JSPS KAKENHI under Grant Nos. 25220911 and 26820311. This work utilized facilities supported in part by the NSF under Agreement No. DMR-0944772. The authors also thank Dr. Nina Verdal for with the QENS measurements. As a to our authors and this provides by the Such materials are and may be for but are not or support from than should be to the The is not for the or of any by the than should be to the corresponding for the

Both LiCB9H10 and NaCB9H10 exhibit liquid-like cationic conductivities (≥0.03 S cm−1) in their disordered hexagonal phases near or at room temperature. These unprecedented conductivities and favorable stabilities enabled by the large pseudoaromatic polyhedral anions render these materials in their pristine or further modified forms as promising solid electrolytes in next-generation, power devices.

Different procedures for analysis of particle sizes by the X-ray diffraction method are compared by the example of nanoparticles of nickel and iron(3+) oxide (Fe2O3). A modified Warren-Averbach method is proposed for the analysis of the X-ray diffraction line profile based on the approximation by the Voigt function, which yields stable solutions, and the efficiency of the method is shown. The analysis within the frame-work of the Warren-Averbach method makes it possible to restore the distribution function of nanoparticles (crystallites) over true diameters, which satisfactorily correlates with electron microscopy data. The applicability of the Warren-Averbach method to the estimation of crystallite sizes by the analysis of a single diffraction line is substantiated. The range of the applicability of the Scherrer, Williamson-Hall, Warren-Averbach, and modified Warren-Averbach methods to the substructure analysis by the X-ray diffraction is determined as depending on the method of nanostructure formation.

Solid lithium and sodium closo-polyborate-based salts are capable of superionic conductivities surpassing even liquid electrolytes, but often only at above-ambient temperatures where their entropically driven disordered phases become stabilized. Here we show by X-ray diffraction, quasielastic neutron scattering, differential scanning calorimetry, NMR, and AC impedance measurements that by introducing “geometric frustration” via the mixing of two different closo-polyborate anions, namely, 1-CB9H10– and CB11H12–, to form solid-solution anion-alloy salts of lithium or sodium, we can successfully suppress the formation of possible ordered phases in favor of disordered, fast-ion-conducting alloy phases over a broad temperature range from subambient to high temperatures. This result exemplifies an important advancement for further improving on the remarkable conductive properties generally displayed by this class of materials and represents a practical strategy for creating tailored, ambient-temperature, solid, superionic conductors for a variety of upcoming all-solid-state energy devices of the future.

This review is focused on recent progress in the synthesis and design of different forms of nanostructured silver sulfide from nanopowders to colloidal solutions, quantum dots and heteronanostructures.

Abstract Polymeric carbon nitride materials have been used in numerous light‐to‐energy conversion applications ranging from photocatalysis to optoelectronics. For a new application and modelling, we first refined the crystal structure of potassium poly(heptazine imide) (K‐PHI)—a benchmark carbon nitride material in photocatalysis—by means of X‐ray powder diffraction and transmission electron microscopy. Using the crystal structure of K‐PHI, periodic DFT calculations were performed to calculate the density‐of‐states (DOS) and localize intra band states (IBS). IBS were found to be responsible for the enhanced K‐PHI absorption in the near IR region, to serve as electron traps, and to be useful in energy transfer reactions. Once excited with visible light, carbon nitrides, in addition to the direct recombination, can also undergo singlet–triplet intersystem crossing. We utilized the K‐PHI centered triplet excited states to trigger a cascade of energy transfer reactions and, in turn, to sensitize, for example, singlet oxygen ( 1 O 2 ) as a starting point to synthesis up to 25 different N‐rich heterocycles.

The chemistry of heterocyclic compounds has traditionally been and remains a bright area of chemical science in Russia. This is due to the fact that many heterocycles find the widest application. These compounds are the key structural fragments of most drugs, plant protection agents. Many natural compounds are also derivatives of heterocycles. At present, more than half of the hundreds of millions of known chemical compounds are heterocycles. This collective review is devoted to the achievements of Russian chemists in this field over the last 15–20 years. The review presents the achievements of leading heterocyclists representing both RAS institutes and university science. It is worth noting the wide scope of the review, both in terms of the geography of author teams, covering the whole of our large country, and in terms of the diversity of research areas. Practically all major types of heterocycles are represented in the review. The special attention is focused on the practical applications of heterocycles in the design of new drugs and biologically active compounds, high-energy molecules, materials for organic electronics and photovoltaics, new ligands for coordination chemistry, and many other rapidly developing areas. These practical advances would not be possible without the development of new fundamental transformations in heterocyclic chemistry.<br> Bibliography — 2237 references.

The lower limit of the applicability of the Scherrer formula has been established by calculating the diffraction patterns from model nanoparticles by the Debye formula. Particle size was calculated using the Scherrer formula for different hkl-peaks. The obtained data of particle sizes were compared with "real" sizes of model particles in the same hkl-directions. The form-factor K hkl was analyzed as main correction of Scherrer formula. It was shown that the Scherrer formula error increases nonlinearly at particle sizes less than 4 nm. For any hkl direction, the absolute error of average particle size determination using formula does not exceed 0.3 nm. Analysis shows that average particle size can be determined by Scherrer formula from single diffraction peak of experimental pattern for center-symmetrical particles.

This work presents a detailed review of the development of distributed acoustic sensors (DAS) and their newest scientific applications. It covers most areas of human activities, such as the engineering, material, and humanitarian sciences, geophysics, culture, biology, and applied mechanics. It also provides the theoretical basis for most well-known DAS techniques and unveils the features that characterize each particular group of applications. After providing a summary of research achievements, the paper develops an initial perspective of the future work and determines the most promising DAS technologies that should be improved.

The polyfunctional nature of chitosan enables its application as a polymer ligand not only for the recovery, separation, and concentration of metal ions, but for the fabrication of a wide spectrum of functional materials. Although unmodified chitosan itself is the unique cationic polysaccharide with very good complexing properties toward numerous metal ions, its sorption capacity and selectivity can be sufficiently increased and turned via chemical modification to meet requirements of the specific applications. In this review, which covers results of the last decade, we demonstrate how different strategies of chitosan chemical modification effect metal ions binding by O-, N-, S-, and P-containing chitosan derivatives, and which mechanisms are involved in binding of metal cation and anions by chitosan derivatives.

New anxiolytics have been discovered by prediction of biological activity with computer programs pass and derek for a heterogeneous set of 5494 highly chemically diverse heterocyclic compounds (thiazoles, pyrazoles, isatins, a-fused imidazoles and others). The majority of tested compounds exhibit the predicted anxiolytic effect. The most potent activity was found in 2-(4-nitrophenyl)-3-(4-phenylpiperazinomethyl)imidazo[1,2-a]pyridine 8, 1-[(4-bromophenyl)-2-oxoethyl]-3-(1,3-dioxolano)-2-indolinone 3, 5-hydroxy-3-methoxycarbonyl-1-phenylpyrazole 5 and 2-(4-fluorophenyl)-3-(4-methylpiperazinomethyl)imidazo[1,2-a]pyridine 7. The application of the computer-assisted approach significantly reduced the number of synthesized and tested compounds and increased the chance of finding new chemical entities (NCEs).