Borglaursen0371

Three mixed-alkali-metal fluorooxoborates, KNaB3O4F3 (I), K2B3O4F3 (II), and KCsB3O4F3 (III), were acquired in a closed system. I-III are isomorphic and adopt orthorhombic structures [Pbcn (No. 60)] with wavy parallelly arranged pseudolayers composed of ∞1[B3O4F3] chains, which exhibit slight differences in the arrangement modes of the fundamental building blocks. First-principles calculations illustrate that they all have moderate birefringence and large band gaps on the order of 7.0 eV, suggesting deep-ultraviolet (DUV) cutoff edges. In order to investigate the main source of the optical properties, the electronic structure and anisotropy of the response electron distribution were analyzed. Experimental characterizations for I confirm the structure and DUV transparence ability.Piezoelectric single-crystal composites (PSCCs) have been studied and applied because of their improved resolution and power source level performance in underwater acoustic transducer applications relative to traditional piezoelectric ceramic composites (PCCs). Currently, the methods to fabricate curved PSCCs are mostly derived from PCCs, including molding with flexible backing, molding with heating, and molding with the casting rubber method. Unfortunately, the methods mentioned above are not suitable for preparing curved PSCCs for underwater acoustic transducer applications because of their brittleness, the large anisotropy of piezoelectric single crystals, and the high thickness (>2 mm) of PSCCs for achieving the low operating frequency ( less then 700 kHz). In the present work, we proposed a preparation method, 3D-printing-assisted dice and insert technology, and successfully prepared curved PSCCs with high performance. Although the PSCCs have a low volume fraction of single crystals in this work (∼33%), a high thickness electromechanical factor kt of 86% and a large piezoelectric coefficient d33 of 1550 pC/N were achieved in the curved 1-3 PSCCs, which are superior to other reported PSCCs and PCCs with nearly the same volume fraction of single crystals and piezoelectric ceramics. This work presents a paradigm for fabricating curved PSCCs for underwater acoustic transducers, and this method shows the potential for large-area, special-shaped PSCCs, which are key materials for next-generation underwater acoustic transducers.Prussian white (PW), due to its low cost, easy synthesis, open structure, and fast ion extraction/interaction, is introduced to the electrochromic field. The PW films were successfully grown on indium tin oxide (ITO) glass by a facial hydrothermal method. Impressively, the PW film exhibits excellent electrochemical cycling stability without obvious decay over 10 000 cycles and a high coloration efficiency of 149.3 cm2 C-1. The film also provides the large optical transmittance contrast (over 70%) in a wide wavelength range of 650-800 nm. Furthermore, the PW film shows the rapid coloration and bleaching response. These results suggest that PW is a promising practical candidate of high-performance electrochromic material.Here, we develop a framework for assembly, understanding, and application of functional emulsions stabilized by few-layer pristine two-dimensional (2D) nanosheets. Liquid-exfoliated graphene and MoS2 are demonstrated to stabilize emulsions at ultralow nanosheet volume fractions, approaching the minimum loading achievable with 2D materials. These nanosheet-stabilized emulsions allow controlled droplet deposition free from the coffee ring effect to facilitate single-droplet devices from minute quantities of material or assembly into large-area films with high network conductivity. To broaden the range of compositions and subsequent applications, an understanding of emulsion stability and orientation in terms of surface energy of the three phases is developed. Importantly, this model facilitates determination of the surface energies of the nanosheets themselves and identifies strategies based on surface tension and pH to allow design of emulsion structures. Finally, this approach is used to prepare conductive silicone emulsion composites with a record-low loading level and excellent electromechanical sensitivity. The versatility of these nanosheet-stabilized emulsions illustrates their potential for low-loading composites, thin-film formation and surface energy determination, and the design of functional structures for a range of segregated network applications.The crystal structure of atomically defined colloidal II-VI semiconductor nanoplatelets (NPLs) induces the self-assembly of organic ligands over thousands of square nanometers on the top and bottom basal planes of these anisotropic nanoparticles. NPLs curl into helices under the influence of the surface stress induced by these ligands. learn more We demonstrate the control of the radii of NPL helices through the ligands described as an anchoring group and an aliphatic chain of a given length. A mechanical model accounting for the misfit strain between the inorganic core and the surface ligands predicts the helices' radii. We show how the chirality of the helices can be tuned by the ligands anchoring group and inverted from one population to another.High-output flexible piezoelectric nanogenerators (PENGs) have achieved great progress and are promising applications for harvesting mechanical energy and supplying power to flexible electronics. In this work, unique core-shell structured Ga-PbZrxTi1-xO3 (PZT)@GaOx nanorods were synthesized by a simple mechanical mixing method and then were applied as fillers in a poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) matrix to obtain highly efficient PENGs with excellent energy-harvesting properties. The decoration of gallium nanoparticles on PZT @GaOx nanorods can amplify the local electric field, facilitate the increment of polar β-phase fraction in P(VDF-TrFE), and strengthen the polarizability of PZT and P(VDF-TrFE). The interfacial interactions of GaOx and P(VDF-TrFE) are also in favor of an increased β-phase fraction, which results in a remarkable improvement of PENG performance. The optimized Ga-PZT@GaOx/P(VDF-TrFE) PENG delivers a maximum open-circuit voltage of 98.6 V and a short-circuit current of 0.3 μA with 9.8 μW instantaneous power under a vertical force of 12 N at a frequency of 30 Hz. Such a PENG exhibits a stable output voltage after 6 000 cycles by the durability test. Moreover, the liquid gallium metal offers a mechanical matching interface between rigid PZT and the soft polymer matrix, which benefits the effective, durable mechanical energy-harvesting capability from the physical activities of elbow joint bending and walking. This research renders a deep association between a liquid metal and piezoelectric ceramics in the field of piezoelectric energy conversion, offering a promising approach toward self-powered smart wearable devices.Electrochemical CO2 reduction (eCO2R) enables the conversion of waste CO2 to high-value fuels and commodity chemicals powered by renewable electricity, thereby offering a viable strategy for reaching the goal of net-zero carbon emissions. Research in the past few decades has focused both on the optimization of the catalyst (electrode) and the electrolyte environment. Surface-area normalized current densities show that the latter can affect the CO2 reduction activity by up to a few orders of magnitude.In this Account, we review theories of the mechanisms behind the effects of the electrolyte (cations, anions, and the electrolyte pH) on eCO2R. As summarized in the conspectus graphic, the electrolyte influences eCO2R activity via a field (ε) effect on dipolar (μ) reaction intermediates, changing the proton donor for the multi-step proton-electron transfer reaction, specifically adsorbed anions on the catalyst surface to block active sites, and tuning the local environment by homogeneous reactions. To be specifictrate general predictive capabilities. The major challenges in our understanding of the electrolyte effect in eCO2R are (i) the long time scale associated with a dynamic ab initio picture of the catalyst|electrolyte interface and (ii) the overall activity determined by the length-scale interplay of intrinsic microkinetics, homogeneous reactions, and mass transport limitations. New developments in ab initio dynamic models and coupling the effects of mass transport can provide a more accurate view of the structure and intrinsic functions of the electrode-electrolyte interface and the corresponding reaction energetics toward comprehensive and predictive models for electrolyte design.Resonant nanoelectromechanical systems (NEMS) based on two-dimensional (2D) materials such as molybdenum disulfide (MoS2) are interesting for highly sensitive mass, force, photon, or inertial transducers, as well as for fundamental research approaching the quantum limit, by leveraging the mechanical degree of freedom in these atomically thin materials. For these mechanical resonators, the quality factor (Q) is essential, yet the mechanism and tuning methods for energy dissipation in 2D NEMS resonators have not been fully explored. Here, we demonstrate that by tuning static strain and vibration-induced strain in suspended MoS2 using gate voltages, we can effectively tune the Q in 2D MoS2 NEMS resonators. We further show that for doubly clamped resonators, the Q increases with larger DC gate voltage, while fully clamped drumhead resonators show the opposite trend. Using DC gate voltages, we can tune the Q by ΔQ/Q = 448% for fully clamped resonators, and by ΔQ/Q = 369% for doubly clamped resonators. We develop the strain-modulated dissipation model for these 2D NEMS resonators, which is verified against our measurement data for 8 fully clamped resonators and 7 doubly clamped resonators. We find that static tensile strain decreases dissipation while vibration-induced strain increases dissipation, and the actual dependence of Q on DC gate voltage depends on the competition between these two effects, which is related to the device boundary condition. Such strain dependence of Q is useful for optimizing the resonance linewidth in 2D NEMS resonators toward low-power, ultrasensitive, and frequency-selective devices for sensing and signal processing.During early gametogenesis the incomplete mitotic divisions occur. The cytokinesis is blocked and the sister cells do not fully separate. Instead, they stay connected via modified contractile rings known as stable intercellular bridges or ring canals. Intercellular bridges are broad cytoplasmic strands (from 0,2μm to 20μm in diameter), which allow to exchange the gene products and organelles between interconnected cells. Such syncytial structures are termed germ-line cysts. As a rule, cysts are formed during spermatogenesis and they interconnect germ cells till sperm formation. In the female germ-line (oogenesis) cysts may not form at all, may be formed for a short period of time (till early meiosis) or may function till late oogenesis. Despite of universal mechanism of cysts formation (incomplete cytokinesis and bridge formation) there are substantial differences in cysts organization and functioning between taxa. The present paper gives the basic knowledge about formation and functioning of male and female germ-line cysts.