Real-time monitoring of Yb vapor density using an extended cavity violet diode laser

Based on laser absorption spectroscopy (LAS), we developed a vapor density monitor for controlling the vaporization rate of Yb using a tunable diode laser. The laser source consisted of an extended cavity violet diode laser which has an emission wavelength of 398.8 nm coincident with the Yb absorption transition line, 6s(2) 1S(0)-6s6p 1P(1). The light emitted from the diode laser was transmitted across an atomic vapor column generated by heating the Yb metal, while the laser frequency was scanned across the atomic transition line. By comparing the amount of incident light to the amount of light transmitted after the light passed through the vapor column, the vapor density was determined using the Beer's law. From the experimental results, we demonstrated that the diode-laser-based LAS operated successfully for the real-time monitoring of the Yb vapor density.     

Environmentally benign oxidation reaction of aldehydes to their corresponding carboxylic acids using Pd/C with NaBH4 and KOH

Pd/C catalyst in aqueous methanol with sodium borohydride and potassium hydroxide under the air efficiently oxidized aldehydes to their corresponding carboxylic acids at room temperature. The utilization of room temperature reaction, aqueous methanol solvent, and the open-air conditions make this manipulation very interesting for economic and environmental perspectives.     

Dual bin packing with items of random sizes

Given a collection of items and a number of unit size bins, the dual bin packing problem requires finding the largest number of items that can be packed in these bins. In our stochastic model, the item sizesX ₁,,X _n are independent identically distributed according to a given probability measure. Denote byN _n =N _n (X ₁,,X _n ) the largest number of these items that can be packed in an bins, where 0<a<1 is a constant. We show thatb = lim _n E(N _n )/n exists, and that the random variable (N _n –nb)/ converges in distribution. The limit is identified as the distribution of the supremum of a certain Gaussian process cannonically attached to. This research is in part supported by NSF grant CCR-8801517 and CCR-9000611.This research is in part supported by NSF grant DMS-8801180.     

On the global and cubic convergence of a quasi-cyclic Jacobi method

Summary In this paper we consider the global and the cubic convergence of a quasi-cyclic Jacobi method for the symmetric eigenvalue, problem. The method belongs to a class of quasi-cyclic methods recently proposed by W. Mascarenhas. Mascarenhas showed that the methods from his class asymptotically converge cubically per quasi-sweep (one quasi-sweep is equivalent to 1.25 cyclic sweeps) provided the eigenvalues are simple. Here we prove the global convergence of our method and derive very sharp asymptotic convergence bounds in the general case of multiple eigenvalues. We discuss the ultimate cubic convergence of the method and present several numerical examples which all well comply with the theory.This work was supported in part by the University of Minnesota Army High Performance Computing Research Center and the U.S Army Contract DAAL03-89-C-0038. The paper was partly written while this author was a visiting faculty in the Department of Mathematics, University of Kansas, Lawrence, Kansas. The first version of this paper was made in July 1990 while this author was visiting AHPCRC.     

2-Dimensional atomic arrangements of Te on Pt(111) whose coverage is higher than 0.25+

Presented is an in-situ electrochemical STM study on the structural evolution of Te layer on Pt(111) whose coverage is higher than 0.25. The irreversibly adsorbed oxygenated Te layer was reduced to a rectangular (2×3) adlayer of elemental Te (_Te=0.25). As additional Te was deposited underpotentially onto the Te-covered Pt(111) surface in a TeO₂-saturated 0.05 M H₂SO₄ solution, the surface structure of Te evolved from the rectangular (2×3) (_Te=0.25) to a rectangular c(2×3) (_Te=0.50) via a rectangular c(3×3) (_Te=0.33). The adsorbed elemental Te was mobile enough to compress the superlattice structure to denser ones, so that the resulting Te layer became electrochemically inactive in the potential range below 0.55 V.Dedicated to Professor György Horányi, Hungary, on the occasion of his 70th birthday.     

Magnesium ion conducting solid polymer blend electrolyte based on biodegradable polymers and application in solid-state batteries

Ionics - Magnesium ion conducting solid polymer blend electrolyte based on biodegradable polymers polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) mixed with different molecular weight...     

Grafting Titanocene on Hydrophilic Amorphous Silica:Synthesis of an Effective Catalyst for Olefin Epoxidation

Ti/silica catalysts were prepared by grafting titanocene dichloride (Cp₂TiCl₂) on hydrophilic amorphous silica with different Ti contents under mild conditions. The results of FT-IR, UV-vis and XPS analyses proved that titanium was successfully grafted in the form of Ti(IV) on amorphous silica and the maximum content of Ti grafted was found to be ca. 3 wt.%. When cyclohexene epoxidation with TBHP was carried out over these synthesized catalysts, both the activity and the selectivity to epoxide increased with the amount of Ti grafted. This amorphous Ti/silica catalyst showed a higher activity and a higher selectivity to epoxide than Ti-containing molecular sieves, Ti-MCM-41 and Ti-beta, with nearly the same Ti content. With Ti content larger than 3 wt.%, however, anatase phase (TiO₂) was formed to give a lower activity and selectivity to epoxide.     

A rapid,simple and reliable HPLC‐triple quadrupole tandem mass spectrometer method for a simultaneous quantification of irinotecan and its active metabolite 7‐ethyl‐10‐hydroxycamptothecin (SN38) in mouse plasma

A simple, fast and reliable high‐performance liquid chromatography–triple quadrupole mass spectrometry method (HPLC‐MS/MS method) was developed, validated and used for the simultaneous quantification of irinotecan and 7‐ethyl‐10‐hydroxycamptothecin (SN38) in heparinized mouse plasma. Camptothecin was used as the internal standard. A single‐step protein precipitation without evaporation and reconstitution steps was adopted as sample processing method. Our bioanalytical method was validated in compliance with the guidelines from the European Medicines Agency. The lower limit of quantification for both irinotecan and SN38 was 5 ng/mL. The calibration curves for both analytes fitted to a 1/x² weighted linear regression model and ranged from 5 to 1000 ng/mL. The intra‐run and inter‐run precisions were within 8.6%, and the intra‐run and inter‐run accuracies were within 96.4?103.9%. Our validated bioanalytical method was successfully applied to the pharmacokinetic study in mice, in which 4 mg/kg irinotecan was intraperitoneally injected. Copyright © 2014 John Wiley & Sons, Ltd.     

Characterization of electroplated ZnTe coatings

Zinc telluride (ZnTe) layers have been grown on conducting glass substrates using an electrochemical technique and characterized using cyclic voltammetry, X-ray diffractions, UV–vis-near infrared spectroscopy, and scanning electron microscopy (SEM). The reaction kinetics of binary film formation is also discussed. Cyclic voltammetry experiments were performed to elucidate the electrodic processes that occurred when potentials were applied and the optimum potential for electrodeposition were determined. X-ray diffraction studies revealed that the deposited films were polycrystalline in nature with zinc blende cubic structure. The various microstructural parameters were calculated using structural studies. The optical transmission and reflection spectrum were recorded and direct transition band gap energy is estimated about 2.26 eV by Tauc’s plot. The SEM pictures revealed that the nanoneedles protruding from nanorods with bunches of atoms agglomerate each other. The energy dispersive analysis by X-rays spectrum revealed the stoichiometry composition of ZnTe thin film at optimized preparative parameters.