A simple and efficient route for the synthesis of di and tri(bis(indolyl) methanes) as new triarylmethanes

Preparation of di and tri(bis(indolyl) methanes) from di and trialdehydes and indoles in the presence of silica sulfuric acid was described. Reactions proceeded in good to excellent yields in acetonitrile as solvent at room temperature.     

Massive mesons in Weyl–Dirac theory

In order to study the mass generation of the vector fields in the framework of a conformal invariant gravitational model, the Weyl–Dirac theory is considered. The mass of the Weyl’s meson fields plays a principal role in this theory, it connects basically the conformal and gauge symmetries. We estimate this mass by using the large-scale characteristics of the observed universe. To do this we firstly specify a preferred conformal frame as a cosmological frame, then in this frame, we introduce an exact possible solution of the theory. We also study the dynamical effect of the massive vector meson fields on the trajectories of an elementary particle. We show that a local change of the cosmological frame leads to a Hamilton–Jacobi equation describing a particle with an adjustable mass. The dynamical effect of the massive vector meson field presents itself in the form of a correction term for the mass of the particle.     

1-(对甲苯基)-2-(三对甲苯基-5-亚磷酰基)乙醛的汞(Ⅱ)配合物的X射线晶体学、光谱表征和理论计算研究

通过2-溴-1-（对甲苯基）乙醛与三（对甲苯基）膦的反应制备α-磷配体：1-（对甲苯基）-2-（三对甲苯基-5-亚磷酰基）乙醛（L）。氯化镉和溴化汞与L分别反应,生成配合物[Cd（L）Cl₂]₂（C1）和[Hg（L）（μ₂-Br）Br]₂（C2）。用IR和NMR（¹H,¹³C,³¹P）对配合物进行了表征。通过单晶X射线衍射测定了C2的结构,并在B3LYP/6-31G^*水平对C2的结构进行了DFT计算研究,以揭示C2的复合反应位点与Schiff碱等亲核基团的相互作用。     

The spectrum and the law of large numbers for infinite-dimensional nonstationary stochastic processes

Helley's 1st and 2nd theorems for trace class-valued distributions are established. Using these theorems the concept of spectrum for an infinite dimensional nonstationary stochastic process is introduced, and a law of large numbers for processes which admit a spectrum is obtained.     

Lattices of minimum covolume are non-uniform

In this article, we prove that a lattice of minimum covolume in a simple Lie group over a local field of positive characteristic is non-uniform if the Weil’s conjecture on Tamagawa numbers [Wei61] holds. This, in part, answers Lubotzky’s conjecture [Lub91].     

Electrochemical Deposition of Gold Nanoparticles on Pencil Graphite by Fast Scan Cyclic Voltammetry

Gold nanoparticles (AuNPs) were electrodeposited on the surface of pencil graphite (PG) by fast scan cyclic voltammetry without using any additives in acidic medium. The effect of deposition time on the size of electrodeposited AuNPs was investigated in sulfuric acid as a supporting electrolyte. The deposition time was varied by varying the scan rate, number of cycles and applied potential range. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X‐ray diffraction (XRD) were used for characterization of PG and electrodeposited AuNPs. The results confirmed that nanosized gold particles (20 ± 8 nm) were deposited on the PG substrate with almost spherical geometry.     

Removal of Oil Spills from Salty Waters by Commercial Organoclays

In this study two commercial organoclays, Cloisite 15A and Cloisite 30B, were used to investigate their potential for removing of light and heavy crude oils from salty waters. The results of batch kinetic studies indicated that the equilibrium time can be reached within 25–30 minutes of contact time. In addition experiments were performed to determine the effect of salinity, temperature, pH and mixing time on the adsorption process. The adsorption isotherms were obtained for the crude oils at equilibrium, at an optimum pH value of 11.73 and temperature of 19°C for which the initial oil contents varied in the range of 100 to 2000 ppm. Experimental results showed that oil sorption onto these organoclays can be described by Freundlich isotherm. Further, it was found that the oil removal efficiency for Cloisite 30B is higher than that of Cloisite 15A and the greater sorption was observed for Gachsaran crude oil onto the organoclays over Soroosh crude oil.     

Comparison Between Long- and Short-Chain Organoclays for Oil Removal from Salty Waters

Two commercial powdered organoclays, Cloisite 15A and Cloisite 30B, as long-chain organoclays, and two organically modified clays with tetramethylammonium chloride (TMA-clay), as short-chain organoclays were used in this study to investigate their potentials for crude oil removal from salty waters. Batch experiments were performed to examine the effect of contact time and pH on the adsorption process. The results showed that the equilibrium time was reached within 25–30 and 50–55 minutes of contact time for long and short-chain organoclays, respectively. In addition, adsorption isotherms were obtained at an optimum pH value of 11.73 and temperature of 19°C for which initial oil contents varied in the range of 100 to 2000 ppm. Experimental results indicated that the sorption of oil onto Cloisite 15A, Cloisite 30B and the organically modified clays can be described by Freundlich isotherm and oil sorption followed the order of modified Cloisite Na > Cloisite 30B > Cloisite 15A > a modified local clay.