An enrichment method of molybdenum on a cellulose nitrate resin for the determination by electrothermal atomic absorption spectrometry coupled with the resin suspension injection.

Cellulose derivative resin (CDR) suspensions containing resin particles of cellulose nitrate (CDR(CN)), cellulose acetate (CDR(CA)), or cellulose triacetate (CDR(CTA)) were prepared as the sorbent for resin suspension injection (RSI) electrothermal atomic absorption spectrometry (ETAAS), in which fine resin particles holding a desired trace element were directly injected into the graphite tube as the suspension. To compare the sorption ability, the distribution ratios of the Mo(VI)-phenylfluorone complex were measured between the aqueous phase and the sorbents, including the CDRs mentioned above and the finely divided anion exchange resin (AR). The results showed that the sorption ability decreases in the following order: CDR(CN) > or = AR > CDR(CA) > or = CDR(CTA). It was concluded that CDR(CN) was able to extract more than 98% of Mo(VI), and was suitable for RSI-ETAAS as well as AR. CDR(CN) was used for the determination of Mo in NIES certified reference materials, No. 10 Rice flour-unpolished; the results showed fairly good agreements between the analytical values and the certified values.     

An ASE Reduction Filter Using Cascaded Optical Fiber Grating Couplers in EDFA Repeater

A new configuration for an ASE reduction filter in EDFA repeaters for WDM optical transmission systems using optical fiber grating couplers (FGCs) was proposed and first demonstrated. The filtering characteristics of the proposed filter for amplified single wavelength signal and 2-channel WDM signals using EDFA were identified. It was found that the filter was effective to improve SNR in optical domain by reducing ASE noise. The required FGC characteristics for the filter were theoretically predicted under the condition that the total filter loss did not exceed 3 dB. More than 70% of drop efficiency was required in each FGC for the application of the proposed filter to an 8-channel WDM system using EDFA repeaters.     

Optical and electric properties of Nb-doped anatase TiO2 single crystal

Nb-doped anatase TiO₂ single crystal has been grown by chemical vapour transport method. Raman spectra shows that the obtained crystal with Nb of 0.08 wt% has typical anatase structure. An absorption band was observed at around 2.2 eV, which seems to be due to the d-d transition in the conduction band. The electron paramagnetic resonance and electric resistivity measurements show that the doped niobium makes quite shallow donor level whose orbital is d_xy-like centered at the titanium position of anatase.     

A -series identity and the arithmetic of Hurwitz zeta functions

Using a single variable theta identity, which is similar to the Jacobi Triple Product identity, we produce the generating functions for values of certain expressions of Hurwitz zeta functions at non-positive integers.     

Re-entrant phase transitions of the Blume-Emery-Griffiths model

We have investigated the spin-1 Ising model on the simple cubic lattice with bilinear, biquadratic interaction and anisotropic energy (BEG model). We have been specially interested in the case of antiferro biquadratic interaction, because the interaction will cause the competition with bilinear interaction and anisotropy. A two-sublattice ordering, so called the staggered quadrupole (SQ) phase, occurs as long as biquadratic interaction is negative large enough. We have obtained a full phase diagram in the whole interaction parameter space (for the positive bilinear interaction) by the Bethe approximation, and found several kinds of phase transitions, such as successive, re-entrant and double re-entrant transitions. These transitions are also confirmed by Monte Carlo simulations on simple cubic lattices.     

Synthesis and biological activities of analogs of a lipid A biosynthetic precursor: 1-O-phosphonooxyethyl-4'-O-phosphono-disaccharides with (R)-3-hydroxytetradecanoyl or tetradecanoyl groups at positions 2, 3, 2' and 3'.

Two novel analogs of a biosynthetic precursor of lipid A (2) were synthesized. The one analog (3) has acyl groups identical to those of 2, and the other (4) has tetradecanoyl groups in place of the (R)-3-hydroxytetradecanoyl groups of 2. Both 3 and 4 possess an alpha-glycosidically-bound phosphonooxyethyl group in place of the alpha-glycosyl phosphate group of 2. Compounds 3 and 4 exhibited definite antitumor activity against Meth A fibrosarcoma and low toxicity in rabbits, as the original compound 2 does. The replacement of the hydroxytetradecanoyl groups with tetradecanoyl groups barely affected the antitumor activity, but slightly enhanced the toxicity in rabbits.     

Synthesis of self‐photosensitizing polyesters containing donor–acceptor norbornadiene moieties and benzophenone groups and their photochemical reactions

The ring‐opening copolymerization of a glycidyl ester derivative having a benzophenone group and the donor–acceptor norbornadiene (D‐A NBD) dicarboxylic acid, 5‐(4‐methoxyphenyl)‐1,4,6,7,7‐pentamethyl‐2,5‐norbornadiene‐2,3‐dicarboxylic acid, monoglycidyl ester derivatives with D‐A NBD dicarboxylic anhydride using tetraphenylphosphonium bromide as a catalyst proceeded smoothly to give novel self‐photosensitizing NBD polymers in good yields. The molecular weight of these polyesters was about 4,000, and lower than that of analogous NBD polymers having no benzophenone group. All the synthesized NBD polymers isomerized smoothly to the corresponding quadricyclane (QC) polymers upon UV irradiation in tetrahydrofuran (THF) solution and in the film state. The rate of the photoisomerization of the D‐A NBD moieties in these polymers was higher than that of the D‐A NBD moieties in the polymer having no photosensitizing group. Furthermore, the rate of the photoisomerization of the D‐A NBD moieties in these polymers was also higher than that of the NBD polymer with low molecular weight photosensitizer in dilute solution. The photo‐irradiated polymers having QC moieties released thermal energies of 146–180 J/g. The D‐A NBD moieties contained in these NBD polymers possessed fair to good fatigue resistance. The degradation of the NBD moieties in these polymers was 15–30% after 50 repeated cycles of interconversion. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2978–2988, 2007