Atomically-flat,chemically-stable,superconducting epitaxial thin film of iron-based superconductor,cobalt-doped BaFe2As2

The epitaxial growth of Fe-based superconductors such as Co-doped SrFe₂As₂ (SrFe₂As₂:Co) was reported recently, but has still insufficient properties for a device application because they have rough surfaces and are decomposed by reactions with water vapor in an ambient atmosphere. This paper reports that epitaxial films of Co-doped BaFe₂As₂ grown at 700 ^°C show the onset superconducting transition temperature of ～20 K. The transition is sharper than those observed on the SrFe₂As₂:Co films, which would originate from their improved crystallinity. These films also have atomically-flat surfaces with step-and-terrace structures and exhibit chemical stability against exposure to water vapor.     

Ultrasonic separation of a suspension for in situ spectroscopic imaging

Optical Review - Application of spectroscopic techniques to suspensions is difficult because optical scattering caused by solid particles reduces the accuracy. At the extreme, dense suspensions...     

Redox Reaction in Ti−Mn Redox Flow Battery Studied by X-ray Absorption Spectroscopy

We performed X-ray absorption studies for the electrolytes of a Ti−Mn redox flow battery (RFB) to understand the redox reaction of the Ti/Mn ions and formation of precipitates in charged catholyte, because suppression of the disproportionation reaction is a key to improve the cyclability of Ti−Mn RFB and enhance the energy density. Hard X-ray absorption spectroscopy with a high transmittance and soft X-ray absorption spectroscopy to directly observe the 3d orbitals were complementarily employed. Moreover, the Ti/Mn 3d electronic structure for each precipitate and solution in the charged catholyte was investigated by using scanning transmission X-ray microscopy: the valence of Mn in the precipitate is mostly attributed to 4+, and the solution includes only Mn²⁺. This charge disproportionation reaction should occur after the Mn ions in the catholyte should be oxidized from Mn²⁺ to Mn³⁺ by charge.     

Discovery of Two-dimensional Hexagonal MBene HfBO and Exploration on its Potential for Lithium-Ion Storage

The practical applications of two-dimensional (2D) transition-metal borides (MBenes) have been severely hindered by the lack of accessible MBenes because of the difficulties in the selective etching of traditional ternary MAB phases with orthorhombic symmetry (ort-MAB). Here, we discover a family of ternary hexagonal MAB (h-MAB) phases and 2D hexagonal MBenes (h-MBenes) by ab initio predictions and experiments. Calculations suggest that the ternary h-MAB phases are more suitable precursors for MBenes than the ort-MAB phases. Based on the prediction, we report the experimental synthesis of h-MBene HfBO by selective removal of In from h-MAB Hf₂InB₂. The synthesized 2D HfBO delivered a specific capacity of 420 mAh g⁻¹ as an anode material in lithium-ion batteries, demonstrating the potential for energy-storage applications. The discovery of this h-MBene HfBO added a new member to the growing family of 2D materials and provided opportunities for a wide range of novel applications.     

Superconductivity in an Orbital-Reoriented SnAs Square Lattice: A Case Study of Li0.6Sn2As2 and NaSnAs

Searching for functional square lattices in layered superconductor systems offers an explicit clue to modify the electron behavior and find exotic properties. The trigonal SnAs₃ structural units in SnAs-based systems are relatively conformable to distortion, which provides the possibility to achieve structurally topological transformation and higher superconducting transition temperatures. In the present work, the functional As square lattice was realized and activated in Li_0.6Sn₂As₂ and NaSnAs through a topotactic structural transformation of trigonal SnAs₃ to square SnAs₄ under pressure, resulting in a record-high T_c among all synthesized SnAs-based compounds. Meanwhile, the conductive channel transfers from the out-of-plane p_z orbital to the in-plane p_x+p_y orbitals, facilitating electron hopping within the square 2D lattice and boosting the superconductivity. The reorientation of p-orbital following a directed local structure transformation provides an effective strategy to modify layered superconducting systems.     

Absolute stereochemistry of serricornin,the sex pheromone of cigarette beetle,as determined by the synthesis of its (4S,6R,7R)-isomer

The absolute stereochemistry of serricornin was determined to be (4S,6S,7S) by the synthesis of its (4S,6R,7R)-isomer using a carbohydrate synthon.     

ESR studies of a new phenoxyl-nitroxide hetero biradical

A new phenoxyl-nitroxide hetero biradical was prepared, and the nitrogen hyperfine splitting and g_iso-value of the biradical in toluene have been determined from its solution ESR spectrum.     

Ajugamarin,a new bitter diterpene from ajuga nipponensis makino

The structure of a new bitter neo-clerodane, ajugamarin, isolated from $\text{Ajuga nipponensis}$ Makino, has been elucidated by spectroscopic studies and confirmed by X-ray crystallographic analysis.     

Application of difference NOE-pumping NMR technique and cold-spray ionization mass spectrometry to identify a ligand binding with a protein receptor.

A difference diffusion-based NMR technique and cold-spray ionization mass spectrometry were employed as a solution-based approach for identifying a ligand binding with a protein receptor. The difference diffusion-based NMR technique, called difference NOE-pumping, can directly detect the ligand interacting with a protein receptor. This technique uses a simple pulse sequence and the diffusion filter can easily be optimized. The cold-spray ionization mass spectrometry (CSI-MS), a variant of electrospray ionization mass spectrometry (ESI-MS) operating at low temperature, has been applied to detect the ligand-receptor complex. The efficiency of these techniques for identifying binding ligands is demonstrated with the human serum albumin (HSA)-drug system.     

Fragmentation of tertiary cyclopropanol compounds catalyzed by vanadyl acetylacetonate

Tertiary cyclopropanol compounds react with a catalytic amount of vanadyl acetylacetonate in the presence of oxygen affording β-hydroxyketones and β-diketones. For 3-substituted-bicyclo[4.1.0]alkanols, peroxides are obtained, as are the β-hydroxyketones. Conversely, 2-ethoxycarbonylcyclopropyl silyl ethers produce ethyl γ-oxocarboxylate derivatives given the same reaction conditions.