Polymerization of Methylene Dichloride and Sodium Tetrasulfide: Synthesis and Kinetic Studies

The kinetics of the condensation polymerization of a novel polysulfide polymer based on methylene dichloride and sodium tetrasulfide is studied. The results of the experiments indicated that the reaction order is two. The activation energy obtained from the Arrhenius plot is 1.879 kcal mol^?1, and the pre-exponential frequency factor is A = 27.11 min^?1 at temperature range of 40～60°C. The polymer is characterized by using Fourier transform-infrared and CHN analysis. Thermal properties were evaluated by differential scanning calorimetry. The TGA-DTA was used to find out the thermal stability of polymer. The solvent resistance of the polymer was investigated by the swelling method.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Ab Initio Study of Structures,Metallotropic 1,2-Shifts and Prototropic 1,2-Shifts of Cyclopentadienyl(trimethyl)silane, -germane and -stannane

Molecular structures, metallotropic and prototropic shifts of cyclopentadienyl(trimethyl)silane ( 1 ), cyclopentadienyl(trimethyl)germane ( 2 ), and cyclopentadienyl(trimethyl)stannane ( 3 ) were investigated using ab initio molecular orbital and the Becke, Lee, Yang, and Parr density functional (B3LYP) methods. The results show that the most stable structure of compounds 1-3 has the (CH 3 ) 3 M fragment in the allylic position. The energy barrier of metallotropic shifts in compound 1 is higher than in 2 , and in compound 2 higher than in 3 , in good agreement with experimental data. The cyclopentadienyl rings in compounds 1-3 are found to be planar but this result contradicts the reported experimental data.     

Classifying the transmission resonances of a subwavelength aperture within a thin metallic film by breaking the symmetry

Here by introducing an I-shape structure to break the symmetry of a thin metallic film, the contributions of Fabry–Perot (FP) resonance-like modes and surface plasmon polariton (SPP) resonance-like are determined. The finite difference-time domain (FDTD) simulation is utilized to provide a clear picture of the electromagnetic field distribution and transmission profile. The FP matrix method is employed to specify the contribution of FP resonance. Some of the predicted resonances of the FP matrix method coincide with the simulation result which is labeled as FP resonance-like modes. The remaining resonance modes in transmission profile are considered as SPP resonance-like modes. Our results provide explicit evidence that both FP resonator modes and SPP resonance are responsible for extraordinary optical transmission (EOT) through a subwavelength aperture.     

Determination of Fabry-Perot resonator contribution in light transmission through unsymmetrical nanoslit

The enhanced light transmission through an I-shape aperture is studied by simulation and theory. The transmission profile due to microcavities created in the entrance and exit of the aperture was modified and new peak was observed. By introducing a new formula the refractive index of layers is defined. The Fabry-Perot matrix method is employed to explore the role of Fabry-Perot resonator effect in modified slits, especially I-shape slit in the scope of this work. And the peaks correspond to this effect are determined. The effect of microcavity surface Plasmon polaritons is explored respectively. Both microcavity surface plasmons and Fabry-Perot resonator contribute in transmission enhancement and consider as the origin of extraordinary transmission for unsymmetrical slits.     

A compact frequency selective stop-band splitter by using Fabry Perot nanocavity in a T-shaped waveguide

By utilizing a Fabry-Perot (FP) nanocavity adjacent to T-shaped gap waveguide ports, spectrally selective filtering is realized. When the wavelength of incident light corresponds to the resonance wavelength of the FP nanocavity, the surface plasmons are captured inside the nanocavity, and light is highly reflected from this port. The resonance wavelength is determined by using Fabry-Perot resonance condition for the nanocavity. For any desired filtering frequency the dimension of the nanocavity can be tailored. The numerical results are based on the two-dimensional finite difference time domain simulation under a perfectly matched layer absorbing boundary condition. The analytical and simulation results indicate that the proposed structure can be utilized for filtering and splitting applications.     

Synthesis,Crystal Structure,and Antibacterial Activity of Di-μ-chlorido-bis({2-[(4-methoxyphenyl)-iminomethyl]pyridine-κ2N,N'] Mercury(II)

Crystallography Reports - A coordination polymer [Hg(L)Cl2]n consisting of HgCl2 and Schiff base bidentate ligand (4-methoxyphenyl) pyridine-2yl methyleneamine (L) was prepared and structurally...