Poly(ethylene)glycol/AlCl3 as a Green and Reusable System in the Synthesis of α,α’-bis(substituted-benzylidene) Cycloalkanones

Aluminum chloride has been found to be a highly efficient catalyst for the aldol condensation of aldehydes and cycloketones in poly(ethylene)glycol 400 at room temperature. The reaction is very fast, clean and environmentally benign for the synthesis of a variety of α,α’-bis(substituted-benzylidene) cycloalkanones.Keywords: Aluminum Chloride, Poly(ethylene)glycol, α,α’-bis(substituted-benzylidene) cycloalkanones, Aldol Condensatio

Numerical method for the mixed Volterra-Fredholm integral equations using hybrid Legendre functions

summary:A new method is proposed for the numerical solution of linear mixed Volterra-Fredholm integral equations in one space variable. The proposed numerical algorithm combines the trapezoidal rule, for the integration in time, with piecewise polynomial approximation, for the space discretization. We extend the method to nonlinear mixed Volterra-Fredholm integral equations. Finally, the method is tested on a number of problems and numerical results are given

One-particle spectral function singularities in a one-dimensional gas of spin-1/2 fermions with repulsive delta-function interaction

The momentum, fermionic density, spin density, and interaction dependencies of the exponents that control the (k,ω)-plane singular features of the one-fermion spectral functions of a one-dimensional gas of spin-1/2 fermions with repulsive delta-function interaction both at zero and finite magnetic field are studied in detail. Our results refer to energy scales beyond the reach of the low-energy Tomonaga-Luttinger liquid and rely on the pseudofermion dynamical theory for integrable models. The one-fermion spectral weight distributions associated with the spectral functions studied in this paper may be observed in systems of spin-1/2 ultra-cold fermionic atoms in optical lattices.T.C. and J.M.P.C. would like to thank P.D. Sacramento for fruitful discussions. We ac knowledge the support from NSAF Grant U1530401, NSFC Grant 11650110443, computational resources from CSRC (Beijing), and the FEDER through the COMPETE Program and the Por tuguese FCT in the framework of the Strategic Project UID/FIS/04650/2013. S.N. and J.M.P.C. thank the support of the FCT Grant PTDC/FIS-MAC/29291/2017. J.M.P.C. would like to thank Boston University’s Condensed Matter Theory Visitors Program for support, the hospitality of MIT, and acknowledges the support from FCT Grant SFRH/BSAB/142925/2018

Search for color-suppressed B hadronic decay processes at the Υ(4S) resonance

Using 3.1fb^(-1) of data accumulated at the Υ(4S) by the CLEO-II detector, corresponding to 3.3×10^6 BB̅ pairs, we have searched for the color-suppressed B hadronic decay processes B^(0) → D^(0)(D^(*0))X^0, where X^0 is a light neutral meson π^0, ρ^0, η, η′ or ω. The D^(*0) mesons are reconstructed in D^(*0) → D^(0)π^(0) and the D^0 mesons in D^(0) → K^(-)π^(+), K^(-)π^(+)π^(0) and K^(-)π^(+)π^(+)π^(-) decay modes. No obvious signal is observed. We set 90% C.L. upper limits on these modes, varying from 1.2×10^(-4) for B^(0) → D^(0)π^(0) to 1.9×10^(-3) for B^(0) → D^(*0)η′

CRYSTALLIZATION KINETICS OF GLASS-CERAMICS BY DIFFERENTIAL THERMAL ANALYSIS

The crystallization behavior of fluorphlogopite, a glass-ceramic in the MgO–SiO2–Al2O3–K2O–B2O3–F system, was studied by substitution of Li2O for K2O in the glass composition. DTA, XRD and SEM were used for the study of crystallization behavior, formed phases and microstructure of the resulting glass-ceramics. Crystallization kinetics of the glass was investigated under non-isothermal conditions, using the formal theory of transformations for heterogeneous nucleation. The crystallization results were analyzed, and both the activation energy of crystallization process as well as the crystallization mechanism were characterized. Calculated kinetic parameters indicated that the appropriate crystallization mechanism was bulk crystallization for base glass and the sample with addition of Li2O. Non-isothermal DTA experiments showed that the crystallization activation energies of base glasses was in the range of 234-246 KJ/mol and in the samples with addition of Li2O was changed to the range of 317-322 KJ/mol

Effects of cadmium on morphological structure of sperm in Caspiomyzon wagneri (Kessler, 1870) (Petromyzontiformes : Petromyzontidae)

The present study aimed to investigate effects of the heavy metal Cd on the sperm morphological indices of Caspimyzon wagneri. The sperm were exposed to 0.01, 0.1, 1, 10, 100 and 1000 mg.L-1 Cd for three minutes, three and 36 hours. The sperms exposed to Cd showed an increase in the length, width and surface of the head, flagella degradation and slightly flagella breakage. With increase of Cd concentration or the exposure duration, the damages found in sperms increased. But when exposure to contaminant exceeds than certain period of time,damage effects caused changes in the sperm structure as head length reduction and head width increasing and thereby reducing the sperm’s head surface, complete cutting of flagella at all samples and deformation of the sperm’s head from oval to circular, which these changes became visible during 36 hours of exposure to cadmium.Therefore, the results revealed that the arrival of pollutants including cadmium to the natural reproduction ground of this species due to induction the harmful effects on sperm morphology factors will have adverse effects on sperm function and fertilization rate and reduce them, and as such will be considered a serious threat to the survival generation of this rare species

Coupling function from bath density of states

This is the final version. Available on open access from IOP Publishing via the DOI in this recordModelling of an open quantum system requires knowledge of parameters that specify how it couples to its environment. However, beyond relaxation rates, realistic parameters for specific environments and materials are rarely known. Here we present a method of inferring the coupling between a generic system and its bosonic (e.g., phononic) environment from the experimentally measurable density of states (DOS). With it we confirm that the DOS of the well-known Debye model for three-dimensional solids is physically equivalent to choosing an Ohmic bath. We further match a real phonon DOS to a series of Lorentzian coupling functions, allowing us to determine coupling parameters for gold, yttrium iron garnet (YIG) and iron as examples. The results illustrate how to obtain material-specific dynamical properties, such as memory kernels. The proposed method opens the door to more accurate modelling of relaxation dynamics, for example for phonon-dominated spin damping in magnetic materials.University of Potsda