A semi-batch crystallization system is used to determine growth kinetics and morphology of barium carbonate crystals, under a constant pH value and constant temperature in the various relative supersaturations. Results show that crystal growth rate satisfies a first-order kinetic expression at high relative supersaturation, while at relative supersaturation values lower than 3,  the k...

in this paper, using annular resonator we have designed an adding and dropping filter light based ontwo-dimensional photonic crystals. the shape of ring resonator filter adding and dropping that wehave proposed is race track. this filter has a hexagonal lattice structure of silicon bars withrefractive index 3/46 that is located in the context of air with refractive index 1. transmissionefficien...

we have designed a new type of optical channel drop filter (cdf) based on two dimensionaltriangular lattice photonic crystals. cdf operation is based on coupling to the photonic crystalwaveguide. the proposed structure is optimized to work as a cdf for obtaining the cdfcharacteristics and band structure of the filter the finite difference time domain (fdtd) method andplane wave expansion (pwe) ...

The title compound was prepared via a cross-coupling reaction and its crystal structure has been determined. It crystallized in the triclinic space group P-1 with cell parameters: a = 8.552(2) Å, b = 11.310(2) Å, c = 16.150(3) Å, α = 109.55(3)°, β = 91.45(3)°, γ = 91.28(3)°, V = 1470.6(5) Å3, Z = 2 at 296 K. There is one molecule in the asymmetric unit. In the crystal structure, the neighboring...

We approach the problem of computational crystal structure prediction, implementing an evolutionary algorithm—USPEX (Universal Structure Predictor: Evolutionary Xtallography). Starting from chemical composition we have tested USPEX on numerous systems (with up to 80 atoms in the unit cell) for which the stable structure is known and have observed a success rate of nearly 100%, simultaneously fi...

Two earlier crystal structure predictions (CSP) of aminophenol compounds are checked against experimental structure determinations. One of the predictions classified originally as ‘‘good’’ is verified and is now seen to be somewhat correct. The other prediction, which was classified earlier as ‘‘unclear’’, is incorrect. The two experimental crystal structures are characterized by small and larg...

The compound 3-amino-1,2,4-benzotriazine 1,4-dioxide (tirapazamine, 1) is a potent antitumor agent. We isolated 3-amino-5-methyl-1,2,4-benzotriazine 1-oxide (5) from the reaction tirapazamine with methyl radical and characterized this compound by X-ray crystallography. The crystal structure of 5 provides clear evidence that this carbon-centered radical forms a covalent attachment with the drug ...