Synthesis, structures, and solution behavior of di- and trinuclear titanium(IV)--cyclophosphato complexes

The reaction of the cyclotetraphosphate ion (P(4)O(12)(4)(-)) with [CpTiCl(3)] (Cp = eta(5)-C(5)Me(5)) gives [(CpTi)(2)(P(4)O(12))(2)](2)(-) where the P(4)O(12) ligands adopt a saddle conformation, while that with [(CpTiCl)(3)(mu-O)(3)] leads to [(CpTi)(3)(mu-O)(3)(P(4)O(12))](-) containing a crown form P(4)O(12) ligand; both products feature their unique cage structures. On the other hand, the reactions of the cyclotriphosphate ion (P(3)O(9)(3)(-)) with [(CpTiCl(2))(2)(mu-O)] and [(CpTiCl)(3)(mu-O)(3)] afford [(CpTi)(2)(mu-O)(P(3)O(9))(2)](2)(-) and [(CpTi)(3)(mu-O)(3)Cl(P(3)O(9))](-), respectively, and in both cases the P(3)O(9) ligands bridge two titanium centers with an eta(2):eta(1) mode.     

Grazing-induced crises in hybrid dynamical systems

In hybrid dynamical systems including both continuous and discrete components, an interplay between a continuous trajectory and a discontinuity boundary can trigger a sudden qualitative change in the system dynamics. Grazing phenomena, which occur when a continuous trajectory hits a boundary tangentially, are well known as a representative of such phenomena. We demonstrate that a grazing phenomenon of a chaotic attractor can result in its sudden disappearance and initiate chaotic transients. The mechanism of this grazing-induced crisis is revealed in an illustrative example. Furthermore, we derive a formula to obtain the critical exponent of the power law on the mean duration of chaotic transients.     

Magnetic susceptibility measurements of solutions by surface nanodisplacement detection.

A new principle to measure the magnetic susceptibility of a solution was proposed; it utilized the displacement of solution surface caused by the magnetic force applied to the solution. The interfacial displacement was measured with the sensitivity of 5 nm from a change of the interference fringes, so called Newton Ring, generated from the solution surface and an upper surface of a small plano-convex lens on the bottom wall of a cell. The surface displacement measurement was carried out in a homemade cell attached by one or two small Nd-Fe-B magnets. The performance of this method was investigated by the measurements of magnetic susceptibility of manganese(II) chloride solution and some lanthanide(III) solutions. An excellent linear relationship between the magnetic susceptibility and the interfacial displacement was observed for each solution system. Then, it was demonstrated that this relationship could be used for the determination of the magnetic susceptibility of solutions or the concentration of a solute by using the manganese(II) solution as a standard solution.     

A siloxane polymer lightwave circuit on ceramic substrate applicable to ultrafast optoelectronic multi-chip-modules

Technique for integrating optical waveguide circuits on electrical circuits is developed toward the application to opto-electronic multi-chip modules (O/E-MCM), which enables one to handle ultrafast lightwave pulses and electrical signals on a common circuit board. We use ceramic material as the substrate of O/E-MCM having a multi-layer structure. A siloxane polymer is utilized to form low loss optical waveguides on ceramic substrates by low temperature processes. The waveguide has shown high transparency around 1310 nm. The group velocity dispersion has been measured and shown to become almost zero at wavelength of 1310 nm and about 0.4 fs/cm nm at 1550 nm. An optical circuit has been formed on simple electrical circuit consisting of a thermometer film resistance layer. A Mach–Zehnder interferometer optical switch exhibiting the waveguide extinction ratio of 30 dB, control power of 5 mW, and switching speed of 6 ms has been demonstrated. Thermal management characteristics also have been demonstrated successfully. This single-mode optical waveguide can thus be formed readily on ceramic substrates involving electrical circuit layers; this result confirms its applicability to O/E-MCM.     

Synthesis and thermal characterization of novel poly(tetramethyl‐1,3‐silphenylenesiloxane) derivative with phenol moiety in the main chain

Novel poly(tetramethyl‐1,3‐silphenylenesiloxane) derivative with phenol moiety in the main chain, that is, poly(tetramethyl‐5‐hydroxy‐1,3‐silphenylenesiloxane) ( P1 ), was synthesized and the thermal properties were investigated by differential scanning calorimetry (DSC) and thermogravimetry (TG). P1 was obtained via deprotective hydrogenation of poly(tetramethyl‐5‐benzyloxy‐1,3‐silphenylenesiloxane) ( Pre‐P1 ) catalyzed by 10% palladium on charcoal as well as via direct polycondensation of 3,5‐bis(dimethylhydroxysilyl)phenol ( M2 ). Pre‐P1 was obtained by polycondensation of 1,3‐bis(dimethylhydroxysilyl)‐5‐benzyloxybenzene ( M1 ), catalyzed by 1,1,3,3‐tetramethylguanidinium 2‐ethylhexoate. M1 was prepared by the Grignard reaction using chlorodimethylsilane and 1,3‐dibromo‐5‐benzyloxybenzene followed by the hydrolysis catalyzed by 5% palladium on charcoal. M2 was prepared by deprotective hydrogenation of M1 catalyzed by 10% palladium on charcoal. The obtained P1 was soluble in common organic solvents such as tetrahydrofuran, chloroform, dichloromethane, toluene, and so forth as well as in highly polar solvents as ethanol and methanol in which poly(tetramethyl‐1,3‐silphenylenesiloxane) is insoluble. The glass transition temperature (T_g) of P1 was determined to be 40 °C from DSC, which was much higher than that of poly(tetramethyl‐1,3‐silphenylenesiloxane) (?52 °C), indicating that the intermolecular and/or intramolecular hydrogen bondings based on hydroxyl groups restricted the mobility of the main chain. The temperature at 5% weight loss (T_d5) of P1 (393 °C) determined by TG was lower than that of poly(tetramethyl‐1,3‐silphenylenesiloxane) (ca. 500 °C), indicating that the phenol moieties decline the thermal stability; however, the obtained P1 would promise to be a new reactive‐polymer with phenolic–hydroxyl moieties to develop new functional materials. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 692–701, 2008     

Measurement of low retardation using reflective optical system based on the photoelastic principle

A new measuring technique that can measure retardation and can output magnitude and direction of plane stress in each glass of a panel composed of double transparent pieces of glass has been developed using reflective confocal optics. The linear polarized probe beam is incident to the glass and we can detect a reflected beam converted to orthogonal polarization caused by the photoelastic phenomenon. Using the high extinction ratio (10⁶) beam-displacing prism as a polarization discriminator, we can measure the photoelasticity by rotating the polarization of the probe beam from 0 to π rad without disturbing the optical axis. This system has the ability to measure retardation. The lowest one is estimated as nearly 0.066 nm for 700 μm thickness glass which corresponds to 0.03 MPa stress from our calibration line.