We demonstrate that the compressibility of spinel Si3N4 nanocrystals increases when the pressure is raised above ;40 GPa. Si3N4 nanocrystals initially exhibit an extremely high bulk modulus of 685~45! GPa. But, above 40 GPa, the bulk modulus is reduced to 415~10! GPa. Thus, a critical pressure of ;40 GPa was determined that signifies the onset of size-induced weakening of elastic stiffness in n...

Porous, water-saturated geologic materials exposed to shock wave loading should undergo a gradual transition from a Terzaghi solid to a much stronger and stiffer material as the confining pressure increases over the range of about 0.2 GPa to about 2 GPa. This transition can thus be expected to become important in cases such as high explosive or nuclear cratering events in which ground shocks in...

With the motivation of searching for new superconductors in the Mg-B system, we performed ab initio evolutionary searches for all the stable compounds in this binary system in the pressure range of 0-200 GPa. We found previously unknown, yet thermodynamically stable, compositions MgB3 and Mg3B10. Experimentally known MgB2 is stable in the entire pressure range 0-200 GPa, while MgB7 and MgB12 ar...

The observed “simple cubic” sc phase of elemental Ca at room temperature in the 32–109 GPa range is, from linear-response calculations, dynamically unstable. By comparing first-principles calculations of the enthalpy for five sc-related nonclose-packed structures, we find that all five structures compete energetically at room temperature in the 40–90 GPa range, and three do so in the 100–130 GP...

In situ high-pressure X-ray powder diffraction experiments on LaN up to 60.1 GPa at ambient temperature in a diamond-anvil cell revealed a reversible, first-order structural phase transition starting at 22.8 GPa and completed at 26.5 GPa from the ambient cubic phase (Fm 3m, no. 225) to a tetragonal high-pressure phase (P4/nmm, no. 19, a1⁄4 4.1060(6), c1⁄4 3.0446(6) Å, Z1⁄4 2, wRp1⁄4 0.011), whi...

BACKGROUND Gastro-protective agents (GPA) are co-prescribed with non-steroidal anti-inflammatory drugs (NSAID) to lower the risk of upper gastrointestinal (UGI) events. It is unknown to what extent the protective effect is influenced by therapy adherence. AIM To study the association between GPA adherence and UGI events among non-selective (ns) NSAID users. METHODS The General Practice Rese...

The dependence of the superconducting transition temperature T(c) on nearly hydrostatic pressure has been determined to 67 GPa in an ac susceptibility measurement for a Li sample embedded in helium pressure medium. With increasing pressure, superconductivity appears at 5.47 K for 20.3 GPa, T(c) rising rapidly to approximately 14 K at 30 GPa. The T(c)(P) dependence to 67 GPa differs significantl...

Mg2Si with narrow band gap has attracted increasing interest for its great potential applications. Theoretical calculations have predicted the metallization of Mg2Si under high pressure. In this work, the electrical resistance and Raman spectrum measurements of semiconducting Mg2Si were performed to investigate the metallization of Mg2Si by using diamond anvil cells and strip opposite anvils. A...

Colleges of Business have experienced high growth rates in the past decade and many colleges are imposing minimum grade point average (GPA) requirements for students entering and remaining in the College. A primary reason for this requirement, presumably, is that students with a high GPA are of a high caliber and are more inclined than those with a low GPA to demonstrate higher-order cognitive ...

3-Fluoro-salicylaldoxime, C(7)H(6)FNO(2), unlike many salicylaldoxime derivatives, forms a crystal structure containing hydrogen-bonded chains rather than centrosymmetric hydrogen-bonded ring motifs. Each chain inter-acts with two chains above and two chains below via π-π stacking contacts [shortest centroid-centroid distance = 3.295 (1) Å]. This structure at 6.5 GPa represents the final point ...