Development of copolymer of CR-39 with high sensitivity to low let particles

Several types of copolymers of CR-39 were prepared to find its usefulness as a nuclear track detector of high sensitivity. Track responses of these copolymers were investigated by irradiating energetic ions from proton through Ar. The copolymer of CR-39 monomer with N-isopropylacrylamide (NIPAAm) shows higher sensitivity than that of pure CR-39 for low LET particles such as protons. Preliminary results are reported for the track responses of copolymers (CR-39/NIPAAm) with various contents of NIPAAm as well as the etching properties.     

Structures and fluorescence of secondary products produced from the cope-knoevenagel reaction of 2-phenylpropionaldehyde with methyl cyanoacetate

The Cope-Knoevenagel reaction of 2-phenylpropionaldehyde ( 7 ) with methyl cyanoacetate ( 8 ) produced methyl (E)-2-cyano-4-phenylpent-2-enoate ( 9 ) and the two highly fluorescent secondary products, 2-amino-3-carbomethoxy-6-phenyl-4-(1-phenylethyl)pyridine ( 10 ) and 3-cyano-6-phenyl-4-(1-phenylethyl)-2-pyridone ( 11 ). The structure of 10 was determined by X-ray crystallography while the structure of 11 was confirmed by the conversion of 9 into 11 . The mechanism of their formation is discussed. Fluorescence of 10 and 11 and the related compounds are also described.     

Electrochemical and thermal properties of hyperbranched polymer electrolytes for batteries

Terminal-acetylated hyperbranched poly(ethylene glycol) derivatives containing diethylene, triethylene, and hexaethylene and 3,5-dioxybenzoate branching units (poly-Ac1a, poly-Ac1b, and poly-Ac1c) were synthesized. Electrochemical and thermal properties of the hyperbranched polymer electrolytes with lithium salts such as LiCF₃SO₃ and LiN(CF₃SO₂)₂, the composite hyperbranched polymer electrolytes with LiN(CF₃SO₂)₂ containing α-LiAlO₂ and γ-LiAlO₂ fillers, and the hyperbranched polymer blended poly(ethylene oxide) electrolytes with LiN(CF₃SO₂)₂ were investigated and discussed. Paper presented at the 8th EuroConference on Ionics, Carvoeire, Algarve, Portugal, Sept. 16–22, 2001.     

Trace metal enrichment by automated on-line column preconcentration for flow-injection atomic absorption spectrometry

An on-line column preconcentration technique for flow-injection atomic absorption spectrometry was developed. Diverse metal ions (Cd²⁺, Zn²⁺, Cu²⁺, Mn²⁺, Pb²⁺, Fe³⁺ and Cr³⁺) in solution were concentrated quantitatively by a microcolumn (7-mm × 4-mm i.d.) packed with Muromac A-1, which is an iminodiacetate chelate resin, in a flow-injection system. From the pH dependence of the uptake of the ions, all the divalent metals examined were recovered quantitatively in the pH range 3–5 and the trivalent metals were recovered at a maximum pH of 1. Enrichment factors using 20-ml samples were in the range 90–180-fold for the seven elements and the sampling rate was 13 h^?1. The 3σ detection limits were in the range 0.14–2.1 μg l^?1 and the relative standard deviations for replicate measurements (n=3–4) were in the range 0.7–1.7%. The method was compared with flame and graphite furnace atomic absorption spectrometry. Application to the determination of cadmium and copper in several standard reference materials is described.     

Characteristics of Gain-Guided Laser Diodes with Cylindrical-Mirror Cavity

We have developed highly reliable etched-mirror laser diodes using a dry etching method. The lasers without facet-coating have been operating stably over 2500 h under automatic-power control (APC) at a power of 3 mW/facet at 50°C. The gain-guided laser diodes with a cylindrical-mirror cavity (CMC) have coaxial mirrors and a fan-shaped stripe structure. By decreasing the curvature radius of the inner facet or increasing the stripe width of the inner facet, the beam waist parallel to the junction plane can be moved outside of the laser diode, while the beam waist perpendicular to the junction plane stops at the mirror facet. A particular CMC laser has a low astigmatism of 4.1 μm and a low relative intensity of noise (RIN) less than –134 dB/Hz at 4 mW under 0–1% optical feedback without high frequency current superposition.     

Nano-SIMS analysis of Mg, Sr, Ba and U in natural calcium carbonate.

Concentrations of minor (Mg and Sr) and trace (Ba and U) elements in four natural calcium carbonate samples were first analyzed by inductively coupled plasma mass spectrometry (ICP-MS) after chemical dissolution and calibrated against a standard dolomite. Their homogeneities were checked by in situ laser ablation (LA) ICP-MS with 10-20 spots. The carbonate samples were measured by using a high lateral resolution secondary ion mass spectrometer (Nano-SIMS NS50). A approximately 4 nA O- primary beam was used to sputter a 5-6-microm diameter crater on the sample surface, and secondary positive ions were extracted for mass analysis using an accelerating voltage of 8 kV and a Mattauch-Herzog geometry. A multi-collector system was adjusted to detect 26Mg+, 43Ca+, 88Sr+, 138Ba+, 238U16O+ and 238U16O2+ ions at the same time. A resolving power of 2500-5000 at 10% peak height was attained by an entrance slit set at 40 microm, and each exit slit at 50 microm with adequate flat-topped peaks. The observed 26Mg/43Ca, 88Sr/43Ca, 138Ba/43Ca and 238U16O2/43Ca ratios agreed well with those measured by LA-ICP-MS. Foraminifera shells were analyzed at 5-6 microm scale by Nano-SIMS. There was a large variation of the Mg/Ca ratios, up to +/- 38%, even in a single fragment of the shell, suggesting that although the ratios provide a useful paleoceanographic proxy at bulk scale, they may reflect a more complex pattern at < 10 microm scale.     

Isolation and structures of euonymine and neoeuonymine,alkaloids from Euonymus Sieboldiana blume

Two new alkaloids, euonymine 5 and neoeuonymine 14 were isolated from Euonymus Sieboldiana Blume. The structures of euonymine and neoeuonymine were established to be 5 and 14, respectively, by chemical and spectral means: the structural features of euonymine 5 are that it is a polyhydroxyl sesquiterpene of eudesman type (euonyminol) which is esterified with evoninic acid 3 and six moles of acetic acid. Neoeuonymine 14 was converted to euonymine 5. Direct conversion of evonine 1 to euonymine 5 was also achieved.     

Canonical quantization of the electromagnetic field with Dirac's monopoles

From a lagrangian theory of charge-monopole electrodynamics which uses strings but is free from Dirac's veto, a hamiltonian theory is derived which describes the interaction between electric and magnetic point particles and photons.     

Further studies on palytoxin. II. structure of palytoxin

The full structure of palytoxin, a potent coelenterate toxin, is reported.