A convenient synthesis of 1-aminophosphonates from 1-hydroxyphosphonates

A simple, efficient, and general method has been developed for the synthesis of 1-aminophosphonates from 1-hydroxyphosphonates under solvent-free conditions using microwave irradiation. 1-Aminophosphonates were obtained in high yield and mild conditions by reaction of diethyl 1-hydroxyalkylphosphonates with amines in the presence of acidic alumina.     

A facile synthesis of new 3-(2-benzimidazolyl)-2-alkyl-4-(3H)-quinazolinones under microwave irradiation

Preparation of 2-amino-N-(1-H-benzimidazol-2-yl)benzamide and a variety of new 3-(2-benzimidazolyl)-2-alkyl-4-(3H)-quinazolinones using isatoic anhydride, 2-aminobenzimidazole and orthoesters under microwave irradiation are described.     

Appointment-driven queueing systems with non-punctual customers

Queueing Systems - We consider a single-server queueing system where a finite number of customers arrive over time to receive service. Arrivals are driven by appointments, with a scheduled...     

Quantum game approach for capacity allocation decisions under strategic reasoning

From a common point of view, quantum mechanics, psychology, and decision science disciplines try to predict how unruly systems (atomic particles, human behaviors, and decision makers’ choices) might behave in the future. Effective predicting outcome of a capacity allocation game under various allocation policies requires a profound understanding as how strategic reasoning of decision makers contributes to the financial gain of players. A quantum game framework is employed in the current study to investigate how performance of allocation policies is affected when buyers strategize over order quantities. The results show that the degree of being manipulative for allocation mechanisms is not identical and adopting adaptive quantum method is the most effective approach to secure the highest fill rate and profit when it is practiced under a reasonable range of entanglement levels.

     

Signals of left-right supersymmetry ine + e − collisions

We study chargino and neutralino pair production at the Next Linear e⁺ e⁻ Collider in a supersymmetric left-right model. We investigateon- and off-resonance signals via the processes: and . These reactions could lead to observable signals as they compare with the background signal from W^± -pair production.     

Charge separation versus recombination in dye-sensitized nanocrystalline solar cells: the minimization of kinetic redundancy

In this paper we focus upon the electron injection dynamics in complete dye-sensitized nanocrystalline metal oxide solar cells (DSSCs). Electron injection dynamics are studied by transient absorption and emission studies of DSSCs and correlated with device photovoltaic performance and charge recombination dynamics. We find that the electron injection dynamics are dependent upon the composition of the redox electrolyte employed in the device. In a device with an electrolyte composition yielding optimum photovoltaic device efficiency, electron injection kinetics exhibit a half time of 150 ps. This half time is 20 times slower than that for control dye-sensitized films covered in inert organic liquids. This retardation is shown to result from the influence of the electrolyte upon the conduction band energetics of the TiO2 electrode. We conclude that optimum DSSC device performance is obtained when the charge separation kinetics are just fast enough to compete successfully with the dye excited-state decay. These conditions allow a high injection yield while minimizing interfacial charge recombination losses, thereby minimizing "kinetic redundancy" in the device. We show furthermore that the nonexponential nature of the injection dynamics can be simulated by a simple inhomogeneous disorder model and discuss the relevance of our findings to the optimization of both dye-sensitized and polymer based photovoltaic devices.     

Bulk versus interfacial aqueous solvation of dicarboxylate dianions

Solvation of dicarboxylate dianions of varying length of the aliphatic chain in water clusters and in extended aqueous slabs was investigated using photoelectron spectroscopy and molecular dynamics simulations. Photoelectron spectra of hydrated succinate, adipate, and tetradecandioic dianions with up to 20 water molecules were obtained. Even-odd effects were observed as a result of the alternate solvation mode of the two negative charges with increasing solvent numbers. The competition between hydrophilic interactions of the charged carboxylate groups and hydrophobic interactions of the aliphatic chain leads to conformation changes in large water clusters containing dicarboxylates bigger than adipate. It also leads to a transition from bulk aqueous solvation of small dicarboxylates to solvation at the water/vapor interface of the larger ones. Whereas oxalate and adipate solvate in the inner parts of the aqueous slab, suberate and longer dicarboxylate dianions have a strong propensity to the surface. This transition also has consequences for the folding of the flexible aliphatic chain and for the structure of aqueous solvation shells around the dianions.     

Synthesis and Crystal Structure of a Novel Polymeric Lead(II) Compound: [Pb2(phen)2(N3)3(ClO4)]n

A 2D lead(II) coordination polymer [Pb₂(phen)₂(N₃)₃(ClO₄)]_n,( 1 ) containing 1,10‐phenanthroline (phen) and two different anions, has been synthesized and characterized by elemental analysis, IR and ¹H NMR spectroscopy and X‐ray crystallography. The single‐crystal X‐ray data show two different kinds of Pb²⁺ ions with coordination numbers of eight, Pb1 = PbN₆O₂ and Pb2 = PbN₈, with hemidirected and holodirected structures, respectively. The supramolecular features in 1 is negiotated through the weak but directional C‐H···O and C‐H···N interactions and aromatic π–π stacking interactions.