Squeezing out the Catalysts: The Disulphide Bond Exchange in Aryl Disulphides at High Hydrostatic Pressure

Exchange of the disulphide bond is a prominent example of equilibrium reactions. Therefore, the wide library of disulphide exchange reactions requires the application of catalysts, such as reducing agents, strong bases, ultraviolet light, or ultrasounds to stimulate higher conversion yields. We employed the pressure between 100 and 400 MPa, for promoting the exchange reactions between various homodimeric aryl disulphides and for optimized conditions obtained 100 % yields and pure single-crystal form of the heterodimer. The reactions were performed in a diamond-anvil cell, as well as in a hydraulic piston-and-cylinder press, and the products were characterized by X-ray diffraction, mass and NMR spectroscopy. <br>

Squeezing out the Catalysts: The Disulphide Bond Exchange in Aryl Disulphides at High Hydrostatic Pressure

Exchange of the disulphide bond is a prominent example of equilibrium reactions. Therefore, the wide library of disulphide exchange reactions requires the application of catalysts, such as reducing agents, strong bases, ultraviolet light, or ultrasounds to stimulate higher conversion yields. We employed the pressure between 100 and 400 MPa, for promoting the exchange reactions between various homodimeric aryl disulphides and for optimized conditions obtained 100 % yields and pure single-crystal form of the heterodimer. The reactions were performed in a diamond-anvil cell, as well as in a hydraulic piston-and-cylinder press, and the products were characterized by X-ray diffraction, mass and NMR spectroscopy. <br>

Squeezing out the Catalysts: The Disulphide Bond Exchange in Aryl Disulphides at High Hydrostatic Pressure

Exchange of the disulphide bond is a prominent example of equilibrium reactions. Therefore, the wide library of disulphide exchange reactions requires the application of catalysts, such as reducing agents, strong bases, ultraviolet light, or ultrasounds to stimulate higher conversion yields. We employed the pressure between 100 and 400 MPa, for promoting the exchange reactions between various homodimeric aryl disulphides and for optimized conditions obtained 100 % yields and pure single-crystal form of the heterodimer. The reactions were performed in a diamond-anvil cell, as well as in a hydraulic piston-and-cylinder press, and the products were characterized by X-ray diffraction, mass and NMR spectroscopy. <br>

Determination of Low Loss in Isotopically Pure Single Crystal 28Si at Low Temperatures and Single Microwave Photon Energy

The low dielectric losses of an isotopically pure single crystal 28Si sample were determined at a temperature of 20 mK and at powers equivalent to that of a single photon. Whispering Gallery Mode (WGM) analysis revealed large Quality Factors of order 2 × 106 (dielectric loss ~5 × 10−7) at high powers, degrading to 7 × 105 (dielectric loss ~1.4 × 10−6) at single photon energy. A very low-loss narrow line width paramagnetic spin flip transition was detected with extreme sensitivity in 28Si, with very small concentration below 1011 cm−3 (less than 10 parts per trillion) and g-factor of 1.995 ± 0.008. Such determination was only possible due to the low dielectric photonic losses combined with the long lifetime of the spin transition (low magnetic loss), which enhances the magnetic AC susceptibility. Such low photonic loss at single photon energy combined with the narrow line width of the spin ensemble, indicate that single crystal 28Si could be an important crystal for future cavity QED experiments.

FTMP-BASED MODELING AND SIMULATION OF MAGNESIUM

The present study proposes a constitutive model for deformation twinning which takes into account the twin degrees of freedom via incompatibility tensor model based on Field Theory of Multiscale Plasticity (FTMP). The model is introduced in the hardening law in the FTMP-based crystalline plasticity framework, which is further implemented into a finite element code. Deformation analyses are made for pure single crystal magnesium with HCP structure, and the descriptive capabilities of the proposed model are confirmed based on critical comparisons with experimental data under plain–strain compression in multiple orientations, available in the literature. The simulated results are demonstrated to successfully reproduce the unique stress–strain responses induced by twinning. The evolution of the relative activities of the various slips, and twin mechanisms for each orientation are extensively examined.