Preparation and certification of the new reference materials; plastics (disk form, JSAC 0621-0625) for determination of mercury using x-ray fluorescent analysis.

The Japan Society for Analytical Chemistry has developed some new plastic certified reference materials (CRMs) for the analysis of mercury in polyester disks using XRF analysis. These CRMs (named as JSAC 0621-0625) were prepared by casting polyesters including a toluene solution of organometallic compounds as a standard. Concentrations of the five levels of mercury ranged from 0 to 250 mg/kg. Homogeneity tests of prepared disks had shown excellent results. Interlaboratory comparison study for the certification was performed by 15 laboratory participants. The z-scores in robust statistical method was applied for the evaluation of outliers. The certified values were assigned after discarding outliers. The uncertainties of certified values were determined as the confidence levels of 95%.     

Synthetic studies on macrolactin A by using a (diene)Fe(CO)3 complex

The stereoselective synthesis of the two segments 3 and 4 of macrolactin A 1 is described. Macrolactin A is a 24-membered polyene macrolide antibiotic, which is of interest due to a strong activity against B16-F10 murine tumor cell and HIV-1 virus. The key step of the synthesis is the 1,2-migration reaction of a (diene)Fe(CO)₃ complex with a introduction of the thiol group to construct the unstable (E,Z)-conjugated dienic moiety (C8-C11).     

Fluorous distannoxane-catalyzed acetylation of alcohols in heterogeneous single fluorous solvent system

Acetylation of alcohols with an equivalent amount of acetic anhydride is feasible in the presence of fluorous distannoxane catalyst in heterogeneous single fluorous system. The fluorous layer containing catalyst can be recycled and reused at least 10 times.     

Statevector reduction in discrete time: A random walk in Hilbert space

A simple model is presented in which the statevector evolves every seconds in one of two ways, according to a particular probability rule. It is shown that this random walk in Hilbert space results in reduction of the statevector. It is also shown how the continuous spontaneous localization (CSL) theory of statevector reduction is achieved as a limiting case of this model, exactly as Brownian motion is a limiting case of ordinary random walk. Finally, a slightly different but completely equivalent form of the CSL equations suggested by the simple model given here is discussed.     

Generation of 360-nm ultraviolet light in first-order periodically poled bulk MgO:LiNbO3

Ultraviolet second-harmonic generation in first-order periodically poled MgO:LiNbO3 is presented. Using a high-voltage multipulse application method, we fabricated a first-order nonlinear grating with a period of 1.8 microm and depth of approximately 150 microm over 10-mm interaction length in a 1-mm-thick MgO:LiNbO3 substrate. In a single-pass configuration, continuous-wave 30-mW UV light at 362.5 nm was generated for a fundamental power of 522 mW, corresponding to a normalized conversion efficiency of 11%/W.     

Near-Field and Polarized Evanescent Field Excited Fluorescence of Self-Organized Particle Arrays of Organic Dye

A wetting/dewetting process was utilized to prepare self-organized organic dye particles of micrometer and submicrometer size. Near-field scanning optical microscopy successfully identified near-field excited near-field fluorescence from single particles. The majority of the small particles with diameters around 2 mm or less, however, did not show fluorescence under near-field observation. In contrast, far-field fluorescence, when excited by a polarized evanescent field, was observed, with the intensity depending on the excitation polarization, indicating that molecules' transition moment within dye particles was oriented parallel to the substrate surface. Single particle fluorescence spectrum consistently showed an identical sharp peak with a large redshift, indicating that the particles were composed of identical dye aggregates similar to J-aggregates. These observations suggest that the near-field at the probe tip was polarized parallel to the probe axis. Another observation, that molecules were oriented in a similar direction among adjacent particles, suggests that the dewetting process contributed to the alignment of the molecular direction among adjacent particles, which further proves that the present specimen was formed by a self-organizing mechanism.     

A large hydrothermal reservoir beneath Taal Volcano (Philippines) revealed by magnetotelluric observations and its implications to the volcanic activity

Taal Volcano is one of the most active volcanoes in the Philippines. The magnetotelluric 3D forward analyses indicate the existence of a large high resistivity anomaly (∼100 Ω·m) with a volume of at least 3 km × 3 km × 3 km, which is capped by a conductive layer (∼10 Ω·m), beneath the Main Crater. This high resistivity anomaly is hypothesized to be a large hydrothermal reservoir, consisting of the aggregate of interconnected cracks in rigid and dense host rocks, which are filled with hydrothermal fluids coming from a magma batch below the reservoir. The hydrothermal fluids are considered partly in gas phase and liquid phase. The presence of such a large hydrothermal reservoir and the stagnant magma below may have influences on the volcano’s activity. Two possibilities are presented. First, the 30 January 1911 explosion event was a magmatic hydrothermal eruption rather than a base-surge associated with a phreato-magmatic eruption. Second, the earlier proposed four eruption series may be better interpreted by two cycles, each consisting of series of summit and flank eruptions.