Visible light-induced charge storage, on-demand release and self-photorechargeability of WO3 film

Tungsten oxide (WO(3)) electrodes subjected to a positive bias are self-photorecharged with alkali cations in the electrolyte during visible light illumination. Upon photoexcitation, part of the photogenerated charges generated by WO(3) is stabilized by the cations and stored in situ within the WO(3) framework. This light-induced storage of charges is subsequently utilized in dark conditions in an on-demand manner and is able to be recharged in the successive illumination cycles. The amount of charges stored is shown to be dependent on the cation ionic radii and the presence of these intercalated cations is verified by X-ray diffraction (XRD) and inductively coupled plasma mass spectroscopy (ICP-MS). This self-photorecharge and on-demand charge-release phenomena demonstrate the ability of WO(3) to supply photoexcited charges under dark condition in a photoelectrochemical reaction with greater flexibility.     

Cessation of Aggregate Growth

Various methods are available for reducing or ceasing growth of aggregating suspensions including the addition of highly charged adsorbents (such as gelatin), reduction of ionic strength by dilution, increase in surface charge by alteration in pH and reduction in suspension temperature. The effectiveness of each of these methods in stopping the aggregation of colloidalhematite without altering the aggregate size distribution is examined in this study. Reduction in aggregate temperature is found to be a particularly effective way of stopping the aggregation of hematite while preserving size distribution information.     

A Parallel Interior Point Method and Its Application to Facility Location Problems

We present a parallel interior point algorithm to solve block structured linear programs. This algorithm can solve block diagonal linear programs with both side constraints (common rows) and side variables (common columns). The performance of the algorithm is investigated on uncapacitated, capacitated and stochastic facility location problems. The facility location problems are formulated as mixed integer linear programs. Each subproblem of the branch and bound phase of the MIP is solved using the parallel interior point method. We compare the total time taken by the parallel interior point method with the simplex method to solve the complete problems, as well as the various costs of reoptimisation of the non-root nodes of the branch and bound. Computational results on two parallel computers (Fujitsu AP1000 and IBM SP2) are also presented in this paper.     

Brownian motion in a quantizing magnetic field

A model previously discussed by the author to study Brownian motion of charged carriers in a quantizing magnetic field is extended to include a Landau level-dependent friction parameter. A phase-space Fokker-Planck equation is used to derive a generalized diffusion equation describing spatial diffusion of the carriers, coupled with random jumps between adjacent Landau levels. This partial differential-difference equation is solved analytically. The longitudinal “global” diffusion coefficient is calculated and shown to be enhanced over the value in the extreme quantum limit.     

Some comments on fuzzy variables

Nahmias introduced the concept of a fuzzy variable as a possible axiomatic framework from which a rigorous theory of fuzziness may be constructed. In this paper we attempt to shed more light on fuzzy variables in analogy with random variables. In particular, we study the problem: if X₁, X₂,…,X_n are mutually unrelated fuzzy variables with common membership function μ and α₁, α₂,…,α_n are real numbers satisfying α_i ? o for every i and Σ_i=1ⁿα_i=1, when does does Z = Σ_{i = 1}ⁿα_iX_i have the same membership function μ?     

The linear response of a one-dimensional electron gas

A not widely used method is employed to calculate the static dielectric function of an electron gas. A specific calculation is presented for a one- dimensional electron system surrounded by a medium of dielectric constant ?₀. The asymptotic, oscillatory, two-body interaction decays more slowly than in the three-dimensional case.     

Some properties of an electron gas in a quantizing magnetic field

The electron gas neutralized by a rigid positive background and in a quantizing magnetic field, is studied in a ‘quasi-classical’ model previously proposed by the author and collaborators. The plasma oscillation of the electron gas shows an acoustic-type dispersion for small wave vector. The potential behind an ion moving along the direction of the magnetic field is calculated and is found to have a sinusoidal behaviour. Some consequences of this potential are pointed out. The energy loss by a moving charge in the electron gas is shown to exhibit some interesting properties. Other quantities such as light scattering and magneto-acoustic oscillations are also discussed. A derivation is given for a ‘quasi-classical’ linear response in the finite relaxation time approximation.     

Migratory insertion of [B(C6F5)2] into C-H bonds: CO promoted transfer of the boryl fragment

The reaction of (eta(5)-C5H5)Fe(CO)2B(C6F5)2 with CO has been shown to proceed via ligand substitution at the metal with accompanying transfer of the boryl fragment (via C-H insertion) to the Cp ring, thereby generating the zwitterion [eta(5)-C5H4B(C6F5)2H]Fe(CO)3 in quantitative yield.     

<Emphasis Type="Italic">In situ</Emphasis> Oxidation of phenol and <Emphasis Type="Italic">o</Emphasis>-aminophenol in the channels of 3d-supramolecular coordination polymers

The host attractive properties of supramolecular coordination polymers of the type _￥³ _\infty^3 [(R₃Sn)₃FeIII(CN)₆], where R = methyl (I), n-butyl (II), and phenyl (III), afford the ability to be used as effective oxidizing reagents for phenol and o-aminophenol forming new host-guest supramolecular coordination polymers. Phenol was oxidized to 1,4-benzoquinone while o-aminophenol was oxidized to poly-o-aminophenol by the polymers I and II and to 2-aminophenoxazin-3-one by the polymer III. The oxidation products were investigated by methods of spectroscopy and high-performance liquid chromatography. The redox reactions were characterized by first-order kinetics. Moreover, mechanisms of the oxidation processes of phenol and o-aminophenol have been proposed.