The Application of Graphene and Its Derivatives to Energy Conversion,Storage, and Environmental and Biosensing Devices

Graphene (GR) and its derivatives are promising materials on the horizon of nanotechnology and material science and have attracted a tremendous amount of research interest in recent years. The unique atom‐thick 2D structure with sp² hybridization and large specific surface area, high thermal conductivity, superior electron mobility, and chemical stability have made GR and its derivatives extremely attractive components for composite materials for solar energy conversion, energy storage, environmental purification, and biosensor applications. This review gives a brief introduction of GR's unique structure, band structure engineering, physical and chemical properties, and recent energy‐related progress of GR‐based materials in the fields of energy conversion (e.g., photocatalysis, photoelectrochemical water splitting, CO₂ reduction, dye‐sensitized and organic solar cells, and photosensitizers in photovoltaic devices) and energy storage (batteries, fuel cells, and supercapacitors). The vast coverage of advancements in environmental applications of GR‐based materials for photocatalytic degradation of organic pollutants, gas sensing, and removal of heavy‐metal ions is presented. Additionally, the use of graphene composites in the biosensing field is discussed. We conclude the review with remarks on the challenges, prospects, and further development of GR‐based materials in the exciting fields of energy, environment, and bioscience.     

Shear viscosity of the ionic liquid 1-n-butyl 3-methylimidazolium hexafluorophosphate [bmim][pf6] computed by reverse nonequilibrium molecular dynamics

Reverse nonequilibrium molecular dynamics and equilibrium molecular dynamics simulations were carried out to compute the shear viscosity of the pure ionic liquid system [bmim][PF 6] at 300 K. The two methods yielded consistent results which were also compared to experiments. The results showed that the reverse nonequilibrium molecular dynamics (RNEMD) methodology can successfully be applied to computation of highly viscous ionic liquids. Moreover, this study provides a validation of the atomistic force-field developed by Bhargava and Balasubramanian ( J. Chem. Phys. 2007, 127, 114510 ) for dynamic properties.     

Synthesis,molecular, and morphological characterization of initial and modified diblock copolymers with organic acid chloride derivatives

Six well defined PS‐b‐PB_1,2 diblock copolymers (PS: polystyrene and PB: polybutadiene) with almost 100% of 1,2 microstructure for the PB segment were synthesized. Size exclusion chromatography (SEC), membrane osmometry (MO) and proton nuclear magnetic resonance spectroscopy (¹H NMR) were used for verification of the molecular characteristics and the 100% ‐1,2 addition for the PB blocks. Modification with heptanoyl or pentadecafluorooctanoyl chloride was accomplished via hydroboration and subsequent oxidation, leading to hydroxylated PB blocks and was verified with ¹H NMR and Fourier transform infrared (FTIR) spectroscopy. Only two samples were modified with both organic acid chloride derivatives. Structural characterization was accomplished via transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS) in all cases. The self‐assembly was more evident in the modified copolymers with the corresponding halides due to the increase of the molecular weight of the modified PB block. Taking into consideration the χN values in each case and comparing the results with those of PS‐b‐PI copolymers already reported in the literature the discrepancies with the theoretical predictions are very small or minimal. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

New Synthesis of Donepezil Through Palladium‐Catalyzed Hydrogenation Approach

A new, economical, and efficient process has been developed for large‐scale synthesis of donepezil 1, an anti‐Alzheimer's drug. The process involves palladium‐catalyzed hydrogenation of (2E)‐5,6‐dimethoxy‐2‐(pyridin‐4‐ylmethylene)indan‐1‐one 6 to provide 5,6‐dimethoxy‐2‐(piperidin‐4‐ylmethyl)indan‐1‐one 8 as a key step.     

Half-Sweep Arithmetic Mean method with composite trapezoidal scheme for solving linear Fredholm integral equations

The main aim of this paper is to examine the effectiveness one of the two-stage iterative method known as Half-Sweep Arithmetic Mean (HSAM) method in solving the dense linear systems generated from the discretization of the first and second kinds of linear Fredholm integral equations. In addition, the formulation and implementation of the HSAM iterative method are also presented. Some illustrative examples are given to point out the efficiency of the proposed method.     

Equilibrium strategies for multiple interdictors on a common network

In this work, we introduce multi-interdictor games, which model interactions among multiple interdictors with differing objectives operating on a common network. As a starting point, we focus on shortest path multi-interdictor (SPMI) games, where multiple interdictors try to increase the shortest path lengths of their own adversaries attempting to traverse a common network. We first establish results regarding the existence of equilibria for SPMI games under both discrete and continuous interdiction strategies. To compute such an equilibrium, we present a reformulation of the SPMI game, which leads to a generalized Nash equilibrium problem (GNEP) with non-shared constraints. While such a problem is computationally challenging in general, we show that under continuous interdiction actions, an SPMI game can be formulated as a linear complementarity problem and solved by Lemke’s algorithm. In addition, we present decentralized heuristic algorithms based on best response dynamics for games under both continuous and discrete interdiction strategies. Finally, we establish theoretical lower bounds on the worst-case efficiency loss of equilibria in SPMI games, with such loss caused by the lack of coordination among noncooperative interdictors, and use the decentralized algorithms to numerically study the average-case efficiency loss.     

Controlled doping of rf sputtered germanium films

Germanium films have been rf sputter deposited on a variety of substrates. A new techniques has been developed to control doping concentrations of the films at predetermined levels for bothp-type as well asn-type films. The hole concentrations of these films could be varied from 10¹⁵ to 2×10¹⁸/cm³ while the electron concentrations could be varied from 10¹⁵ to 5×10¹⁷/cm³ using this technique. Transmission electron microscope studies have been made to study the crystalline quality of the films.     

Influence of rare earth ions on CO oxidation over Ln2NiO4 oxides (Ln=La, Pr or Nd)

CO oxidation was studied over Ln₂NiO₄ compounds in an all-glass static recirculatory system. The reactions were performed at an initial total pressure of 50±2 Torr, in the temperature interval 340–450°C. The apparent activation energy was found to decrease from La to Nd. A correlation between activity and binding energy of oxygen in the compound as well as with the tolerance factor is observed. The role of rare earth ions in these catalysts is discussed.

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CO Ln₂NiO₄ , . 50±2 340–450°C. La Nd. , . .