glass in this work is lower than that of phosphate glass. According to the investigation by Weyl, [6] the above results are on account of the multiabsorption of V 4+ and V 3+ . If one could adjust the composition and modify the procedure properly, more V 3+ and V 4+ states could be converted into the V 5+ state, and the transmission of the vanadate glass would likely be much better. In summary, a novel vanadate glass with remarkable optical transmission was fabricated for the first time. The vanadate glass used in this experiment is suitable for optical applications. Furthermore, when doped with neodymium, it demonstrated quite encouraging laser properties. The results indicated the feasibility of utilizing the novel transparent vanadate glasses in optics, especially in laser-related fiber optics. ExperimentalThe glass samples were prepared from high purity materials. The composition of the sample materials was carefully monitored and the experimental conditions were controlled to obtain a higher concentration of V 5+ in the glass samples. After hundreds of experiments, the glass was developed from the traditional binary composition to a quaternary one: 28V 2 O 5 ±22SiO 2 ±23MO (CaO, BaO, SrO)±27X 2 O (Na 2 O, K 2 O, Cs 2 O) in weight percentage. The batch materials were melted in a platinum crucible inside a silica tube heated by a medium induction furnace. Oxygen gas of 99.99% purity was introduced into the silica tube throughout the whole melting process. The crucible was heated at 1650 K for 2 h. The melted substances were then cast in a graphite mould and annealed. All the samples were fabricated to the size of 25 mm 20 mm 5 mm and optically polished.The absorption spectra were measured using a HITACHI330 spectrometer at room temperature (295 K). The IR spectra were measured using a SHIMADZU RF±5301PC at room temperature. The emission spectra were obtained by exciting the samples with an 805 nm diode laser. The light from the light source was chopped at 80 Hz and focused onto the 5 mm 25 mm faces of the samples. One millimeter from the edge was excited to minimize the re-absorption of the emission. The emission from the samples was focused to a monochrometer and detected by a germanium detector. The signal was intensified with a lock-in amplifier and processed by a computer.The fluorescence lifetime was measured by exciting the samples with a xenon lamp and detected by an S-1 photomultiplier tube. The fluorescence decay curves were recorded and averaged by a computer-controlled transient digitizer. The stimulated-emission cross-section of the neodymium-doped vanadate glass was calculated according to the Judd±Ofelt theory [9,10].

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Ruthenium-catalyzed ring-opening metathesis polymerization (ROMP) of 6-R-B 10 H 13 organodecaboranes containing strained-ring cyclic olefinic substituents has been found to be an important new method of generating poly(organodecaborane) polymers with higher molecular weights than previously attainable. The monomers, 6-(5-cyclooctenyl)-B 10 H 13 (1), 6-(5-norbornenyl)-B 10 H 13 (2), and 6-(4-cyclohexenyl)-B 10 H 13 (3), were synthesized via the titanium-catalyzed decaborane hydroboration of 1 equiv of 1,5cycloctadiene, 2,5-norbornadiene, and 1,4-cyclohexadiene, respectively. The syntheses of the saturated, linked-cage compounds 6,6′-(1,5-cyclooctyl)-(B 10 H 13 ) 2 (4) and 6,6′-(2,5-norbornyl)-(B 10 H 13 ) 2 (5) were also achieved by either the titanium-catalyzed decaborane hydroboration of the remaining double bond of 1 or 2 or the titanium-catalyzed reactions of 1,5-cycloctadiene and 2,5-norbornadiene with an excess amount of decaborane. ROMP of 1 and 2 using either of the Grubbs catalysts, Cl 2 Ru(dCHPh)(PCy 3 )L, L ) PCy 3 (I) or H 2 IMes (II), afforded the poly(6-cyclooctenyldecaborane) (PCD, 6) and poly(6norbornenyldecaborane) (PND, 7) polymers. Molecular weights with M n in excess of 30 kDa were readily obtained with polydispersities between 1.1 and 1.8. Both polymers are stable powders that are soluble in polar organic solvents. Studies of the ceramic conversion reactions of 6 and 7 using TGA, XRD, DRIFT, Raman, SEM, elemental analyses, and density measurements showed that they convert to boron-carbide/ carbon ceramics upon pyrolysis. In accordance with their higher boron-to-carbon ratios, studies of the ceramic conversion reactions of compounds 4 and 5 showed them to be excellent single-source molecular precursors to boron-carbide ceramics with little or no excess carbon.

Simple blends of the poly(norbornenyldecaborane) (PND) boron-carbide preceramic polymer with either of the commercial poly(methylcarbosilane) (PMCS) or allylhydridopolycarbosilane (AHPCS) silicon-carbide preceramic polymers have been found to provide excellent processable precursors to boron-carbide/silicon-carbide ceramic composite materials. The blends exhibited good char yields with tunable ceramic compositions. Certain compositions of the PND/AHPCS derived ceramics also exhibited significant oxidation resistance. Nonwoven mats of PND/PMCS polymer composite fibers were readily obtained by the electrostatic spinning of polymer blend solutions. The pyrolytic ceramic conversion reactions of the PND/PMCS polymer fibers then produced mats of micro- and nanodiameter boron-carbide/silicon-carbide ceramic composite fibers.

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The zeta potential (ZP) is an important and measurable parameter related to the electrical double layer structure at a solid-aqueous solution interface. A high temperature zetameter based on the microelectrophoresis technique was developed to determine the zeta potential and the isoelectric point (IEP) of the metal oxide/water interfaces at temperatures up to 200 °C and pressures up to 50 bar. Design of the microelectrophoresis cell, the main unit of the zetameter, utilized a flow-through concept and the cell internals were made from corrosion resistant materials in order to minimize materials degradation and solution contamination. Two sapphire windows were installed to the microelectrophoresis cell to enable observation of the particle movement under an imposed electrical field. A ZrO2 powder was used to test the zetameter. The ZP for the ZrO2/water system was measured over wide ranges of temperature and pH. The IEP of the ZrO2/water system was found equal to 6.05 at room temperature, 5.00 at 120 °C, and 4.67 at 200 °C. Thus, at room temperature, the IEP obtained was within the confidence interval of the averaged literature data. In addition, it was found that the IEP of ZrO2 was sensitive to temperature and the difference between the IEP and 0.5pKw remained constant (1.00±0.2) with temperatures up to 200 °C.

The compounds 6-(norbornenyl)decaborane and 6-(cyclooctenyl)decaborane were synthesized in >95% yields by the titanium-catalyzed reaction of norbornadiene and cyclooctadiene with decaborane. Ring-opening metathesis polymerization of these monomers employing either first-or second-generation Grubbs catalysts produced the corresponding poly(6-(norbornenyl)decaborane) and poly(6-(cyclooctenyl)decaborane) polymers with M n >30 kDa and polydispersities between 1.1 and 1.8.