Analysis of Th, U, Pu, and Am in radioactive metal waste using extraction chromatography

In order to analyze actinide elements in radioactive metal waste, the dissolution and chemical separation conditions were optimized. The surfaces of a type 304 stainless steel plate and of pipe waste sampled from the prototype advanced thermal reactor (Fugen) were dissolved in mixed acid solution (HNO₃:HCl:H₂O = 1:1:4). The resulting solution was evaporated to dryness and dissolved with 2 mol/dm³ of HNO₃ to prepare sample solutions. In order to analyze trivalent actinide elements in the sample solution containing a large amount of Fe(III) (>0.1 g) using TRU resin, the effect of Fe(III) concentration on the recovery of Am(III) and reduction effect of Fe(III) to Fe(II) with ascorbic acid were studied. On the basis of results of this study, chemical separation scheme was constructed and Pu and Am in the sample solutions were separated. Thorium and U in the sample solutions were separated with UTEVA resin. High recoveries for all experimented elements were obtained from the analysis of spiked sample solutions, the effectiveness of the method was confirmed.     

Preparation,Isolation and Characterization of all of the Regioisomeric 61, 6N-Bis-O-(Monomethoxytrityl) and-(Dimethoxytrityl) Derivatives of Cyclomalto-Olgosaccharides

Abstract

Regioisomeric 6¹, 6ⁿ-bis-O-(monomethoxytrityl) or 6¹, 6ⁿ-bis-O-(dimethoxytrityl) cyclomaltohexaose, -cyclomaltoheptaose (n = 2-4), and -cyclomaltooctaose derivatives (n = 2-5) were prepared by the reaction of cyclomaltohexaose (1, cG₆, αCD), cyclomaltoheptaose (11, cG₇, βCD) or cyclomaltooctaose (21, cG₈, γCD) and 4-monomethoxytrityl chloride or 4,4′-dimethoxytrityl chloride in pyridine. Products were isolated by HPLC. The regiochemical determination of these positional isomers was done by converting these compounds to the respective 6¹, 6ⁿ-bis-O-(tert-butyldimethylsilyl) derivatives¹ whose structures have been already established.     

Simultaneous determination of methylene blue and new methylene blue by slab optical waveguide spectroscopy and artificial neural networks

A slab optical waveguide (SOWG) has been used for study of adsorption of both methylene blue (MB) and new methylene blue (NMB) in liquid-solid interface. Adsorption characteristics of MB and NMB on both bare SOWG and silanized SOWG by octadecyltrichlorosilane (ODS) were compared. The simultaneous determinations of both MB and NMB were explored by flow injection SOWG spectrophotometric analysis and artificial neural networks (ANNs) for the first time. Concentrations of MB and NMB were estimated simultaneously with the ANNs. Results obtained with SOWG were compared with those got by conventional UV-visible spectrophotometry.     

Right-handed current effect on inclusive decays of theB meson

Recent experimental values for the inclusive semileptonic decay branching ratio of theB meson are low compared to the spectator model expectation. That branching ratio is investigated in the right-handed current model. The right-handed current could enhance the nonleptonic decay mode, thereby suppressing the semileptonic branching ratio. Then, the quark mixing matrix of the right-handed sector is restricted to be of one special type and the right-handed neutrino has to be the heavy Dirac one.     

Polynomiality of primal-dual affine scaling algorithms for nonlinear complementarity problems

This paper provides an analysis of the polynomiality of primal-dual interior point algorithms for nonlinear complementarity problems using a wide neighborhood. A condition for the smoothness of the mapping is used, which is related to Zhu’s scaled Lipschitz condition, but is also applicable to mappings that are not monotone. We show that a family of primal-dual affine scaling algorithms generates an approximate solution (given a precision ε) of the nonlinear complementarity problem in a finite number of iterations whose order is a polynomial ofn, ln(1/ε) and a condition number. If the mapping is linear then the results in this paper coincide with the ones in Jansen et al., SIAM Journal on Optimization 7 (1997) 126–140. Research supported in part by Grant-in-Aids for Encouragement of Young Scientists (06750066) from the Ministry of Education, Science and Culture, Japan. Research supported by Dutch Organization for Scientific Research (NWO), grant 611-304-028     

Parallel Implementation of Successive Convex Relaxation Methods for Quadratic Optimization Problems

As computing resources continue to improve, global solutions for larger size quadrically constrained optimization problems become more achievable. In this paper, we focus on larger size problems and get accurate bounds for optimal values of such problems with the successive use of SDP relaxations on a parallel computing system called Ninf (Network-based Information Library for high performance computing).     

Diffusion process of electrons injected from STM tip into AlGaAs/GaAs quantum wells

We have investigated the electron diffusion process in Al_0.3Ga_0.7As/GaAs quantum well (QW) structures by means of scanning tunneling microscope light emission (STM-LE) spectroscopy. The optical measurements were performed on a cleaved (1 1 0) surface at room temperature. The STM-LE spectra were measured by injecting hot electrons from the tip positioned at different distances from the QWs. The emission intensity from individual wells as a function of the tip-well distance was found to decay with two distinct decay constants. From comparison with Monte Carlo simulations for hot electron relaxation, we found that the intervalley scattering from the Γ valley to the L and X valleys has the most significant effect on the diffusion process of the injected electrons.     

Versatile synthesis of epicatechin series procyanidin oligomers, and their antioxidant and DNA polymerase inhibitory activity

Proanthocyanidins, known as condensed tannins or oligomeric flavonoids, exist in many edible plants and show various interesting biological activities. We have developed a simple and versatile method of synthesizing procyanidin oligomers consisting of (−)-epicatechin and (+)-catechin. This method is applicable to the synthesis of various 3-O-substituted oligomers. We report here the stereoselective and length controlled synthesis of [4-8]-condensed (−)-epicatechin series procyanidin oligomers. We described the details of the synthesis of an two tetramers, (−)-epicatechin-(−)-epicatechin-(−)-epicatechin-(−)-epicatechin and (−)-epicatechin-(−)-epicatechin-(−)-epicatechin-(+)-catechin (arecatannin A1), (−)-epicatechin pentamer and two 3,3″,3?-tri-O-galloyl trimers, (−)-epicatechin-(−)-epicatechin-(−)-epicatechin-3,3″,3?-tri-O-gallate and (−)-epicatechin-(−)-epicatechin-(+)-catechin-3,3″,3?-tri-O-gallate with the condensation method using TMSOTf as a catalyst. The ability of DPPH radical scavenging activity and DNA polymerase inhibitory activity of these oligomeric compounds were investigated.