Br NQR relaxation and successive phase transitions of CH3NH3HgBr3

The measurement of ⁸¹Br NQR in CH₃NH₃HgBr₃ has been carried out in the temperature range between 80 and 300 K using a pulse NQR method. The temperature dependence of ⁸¹Br NQR frequencies in CH₃NH₃HgBr₃ has revealed that it undergoes three characteristic successive phase transitions at T?=?123, 184 and 239 K. The phase transition temperature at T?=?239 K is the second-order type, whereas those at T?=?184 and 123 K are the first-order nature of the phase transitions. Each phase transition seems to be closely related to the motions of methyl ammonium cation as a partial or whole. The enhancement of 1/T ₁ at T?=?239 K indicates the onset of the molecular motion of the cation as a whole with increasing temperatures.     

Electric Dipole Moments of Light Nuclei From Chiral Effective Field Theory

Recent calculations of EDMs of light nuclei in the framework of chiral effective field theory are presented. We argue that they can be written in terms of the leading six low-energy constants encoding CP-violating physics. EDMs of the deuteron, triton, and helion are explicitly given in order to corroborate our claim. An eventual non-zero measurement of these EDMs can be used to disentangle the different sources and strengths of CP-violation.     

Spectrophotometric Determination of Carbon Dioxide by Bromothymol Blue Solution in DMF-Water

Spectrophotometric determination of gaseous CO₂ by use of Bromothymol Blue (3,3,-dibromothymolsulfonphthalein) (BTB) and potassium hydroxide solution in a N,N-dimethylformaide (DMF)-water was investigated.     

Seragamides A-F, new actin-targeting depsipeptides from the sponge Suberites japonicus Thiele

Six new depsipeptides, seragamides A-F (1-6), and a known geodiamolide I (7) have been isolated as cytotoxic metabolites from the Okinawan sponge Suberites japonicus. Their structures were elucidated by means of spectroscopic analysis and chemical transformations. Seragamide A (1) promotes the polymerization of G-actin and stabilizes F-actin filaments.     

Design of highly nonlinear dispersion flattened hexagonal photonic crystal fibers for dental optical coherence tomography applications

In this paper, we propose a highly nonlinear dispersion flattened hexagonal photonic crystal fiber (HNDF-HPCF) with nonlinear coefficients as large as 57.5W⁻¹ km⁻¹ at 1.31 μm wavelength for dental optical coherence tomography (OCT) applications. This HNDF-HPCF offers not only large nonlinear coefficient but also very flat dispersion slope and very low confinement losses. Using these characteristics of our proposed PCF, it is shown through simulations by using finite difference method with an anisotropic perfectly matched boundary layer that this PCF offers the efficient supercontinuum (SC) generation for dental OCT applications at 1.31 μm wavelength using a picosecond pulse easily produced by commercially available less expensive laser sources. Coherent length of light source using SC is found 10 μm and the spatial resolutions in the depth direction for dental applications of OCT are found about 6.1 μm for enamel and 6.5 μm for dentin.     

The Synthesis of II-VI Binary Alloys and Organometallic Compounds via Me3SiOR Elimination Reactions

Trimethylsilyl chloride elimination reactions have been well documented. We now report the use of trimethylsilyl acetate elimination reaction in the preparation of binary alloys, HgTe and CdTe. The new compound, (MeHg)₃P, and the known compound (MeHg)₂S have been prepared by the trimethylsilyl acetate elimination reaction and characterized by NMR spectroscopy, electron ionization mass spectroscopy, and elemental analysis.