Nature of some features in Raman spectra of hydroxyapatite‐containing materials

A very broad vibrational band ranging from 1000 up to 4000 cm⁻¹ and two relatively sharp bands at 5000 and 5027 cm⁻¹ are found in the Raman scattering spectrum of hydroxyapatite‐containing films obtained by gas detonation spray method. We developed a theoretical model that interprets the broad band as a result of strong interaction between the high‐frequency hydrogen bond vibrations and lattice phonons. Both sharp bands around 5000 cm⁻¹ are assigned to the overtones of v‐OH vibrations. Copyright © 2016 John Wiley & Sons, Ltd.     

Reversible Switching between Highly Porous and Nonporous Phases of an Interpenetrated Diamondoid Coordination Network That Exhibits Gate‐Opening at Methane Storage Pressures

Herein, we report that a new flexible coordination network, NiL₂ (L=4‐(4‐pyridyl)‐biphenyl‐4‐carboxylic acid), with diamondoid topology switches between non‐porous (closed) and several porous (open) phases at specific CO₂ and CH₄ pressures. These phases are manifested by multi‐step low‐pressure isotherms for CO₂ or a single‐step high‐pressure isotherm for CH₄. The potential methane working capacity of NiL₂ approaches that of compressed natural gas but at much lower pressures. The guest‐induced phase transitions of NiL₂ were studied by single‐crystal XRD, in situ variable pressure powder XRD, synchrotron powder XRD, pressure‐gradient differential scanning calorimetry (P‐DSC), and molecular modeling. The detailed structural information provides insight into the extreme flexibility of NiL₂ . Specifically, the extended linker ligand, L , undergoes ligand contortion and interactions between interpenetrated networks or sorbate–sorbent interactions enable the observed switching.     

Adaptive Chemical Networks under Non‐Equilibrium Conditions: The Evaporating Droplet

Non‐volatile solutes in an evaporating drop experience an out‐of‐equilibrium state due to non‐linear concentration effects and complex flow patterns. Here, we demonstrate a small molecule chemical reaction network that undergoes a rapid adaptation response to the out‐of‐equilibrium conditions inside the droplet leading to control over the molecular constitution and spatial arrangement of the deposition pattern. Adaptation results in a pronounced coffee stain effect and coupling to chemical concentration gradients within the drop is demonstrated. Amplification and suppression of network species are readily identifiable with confocal fluorescence microscopy. We anticipate that these observations will contribute to the design and exploration of out‐of‐equilibrium chemical systems, as well as be useful towards the development of point‐of‐care medical diagnostics and controlled deposition of small molecules through inkjet printing.     

Banach空间中一类四阶奇异边值问题的解的存在性

利用上下解方法研究了Banach空间中一类四阶奇异两点边值问题的解的存在性.     

Phase formation of complex phosphate K<Subscript>4</Subscript>Ti<Subscript>3</Subscript>Ni(PO)<Subscript>4</Subscript> in K<Subscript>2</Subscript>O-P<Subscript>2</Subscript>O<Subscript>5</Subscript>-TiO<Subscript>2</Subscript>-NiO melt solutions

The principles of complex phosphate crystallization in K₂O-P₂O₅-TiO₂-NiO solution melts are studied for the ratios K/P = 0.7?1.4, Ti/P = 0.15, and Ni/Ti = 0.1?2.0. The phase-formation field and parameters are determined for a new complex phosphate K₄Ti₃Ni(PO₄)₆, which is isostructural to langbeinite. A single-crystal X-ray diffraction experiments is carried out for this phosphate (space group P2₁3, a = 9.8247(10) Å).