As a basic study for the development of chromium boride materials which are expected as refractory materials or hard materials, syntheses and sinterings of the chromium borides via solid state reactions and mechanochemical processes of chromium-amorphous boron mixed powders were studied. The single phases of Cr₂B, CrB and CrB₂ were obtained by the solid state reaction in the temperatures of 1400-1500°C. These borides were so unsinterable that could be consolidated by pressure sintering only. The chromium boride of the highest relative density and hardness among the ceramics obtained was CrB₂. By mechanochemical processes, the single phases of CrB₂ and CrB were obtained by milling of Cr-B(molar ratio, 1:2) and Cr-B(1:1) mixed powders by using a planetary ball mill for 20-40h, followed by annealing at 900 and 1000°C, respectively. As-milled Cr-B(1:1) mixed powders were consolidated by both of pressureless and pressure sinterings. These are a reaction sintering because the sinterings are accelerated by the exothermic reaction heat of the unreacted Cr-B in the as-milled mixed powders. The unsinterable powder could be consolidated by pressureless sintering via mechanochemical process. At pressure sintering via mechanochemical process, the sintering temperature lowered and the hardness of ceramics obtained increased.

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The solidus and liquidus curves of the p-dibromobenzne-p-diiodobenzene mixed crystal system in the vicinity of both pure components were estimated by the use of DSC. On the basis of the relationship between temperature(t) and the melted fraction(F), the equilibrium distribution coefficient(k₀) can be obtained by the following equation: k₀=F₁F₂(t_A-t₀)/F₁-F₂{1/F₂(t_A-t₂)-1/F₁(t_A-t₁)} where F₁ and F₂ are fractions melted corresponding to the temperatures t₁ and t₂; t₀ is the temperature at the end of melting of the mixture, i.e. the liquidus temperature, which is equal to the temperature at F=1 and t_A is the melting point of the pure component, respectively. The solid composition(C_s) equilibrium with the liquid phase at the temperature t₀ is given by the product of the initial solute concentration(C₀) and k₀ obtained by the above equation, i.e. C_s=k₀C₀. From the result of DSC for the samples containing about 0.5, 1.0 and 2.0mass% of p-dibromobenzene in p-diiodobenzene and of p-diiodobenzene in p-dibromobenzene, the solidus and liquidus curves on both sides of the low concentrations in the phase diagram were estimated.

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Among the noble metal catalysts tested in the present study, iridium catalyst supported on MFI-type metallosilicate, which had been activated in 10% H₂O-N₂ at 700°C, showed the highest catalytic activity for the selective reduction of NO_x with hydrocarbon under oxygen rich condition. The conversion of NO into N₂ on the activated iridium catalysts was not affected by the presence of water vapor. The characterization by XRD, XPS and TEM revealed that the agglomerated Ir metal was formed in the iridium catalysts showing the high NO_x reduction activity. From FT-IR and TPD measurements, -NO₂ or -ONO, and -CO formed on catalyst surface in NO+C₃H₆+O₂ reaction were found to be intermediates of the selective reduction of NO_x.On the basis of these results, it is inferred that the high NO_x reduction activity of the activated iridium catalyst resulted from the presence of the active oxygen species on activated iridium catalyst which might react with NO and hydrocarbons to form reactive oxygenated intermediates.

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An indirect potentiometric determination of anions(or cations) using a precipitation reaction and a standard addition method, in which the adjustment of the ionic strength of a sample is not required, is proposed.
A certain volume(V_r) of the solution(reactant) containing the precipitant cation A of a known concentration c_r is added to the sample solution of volume V containing the analyte anion B of a concentration c_x. If the composition of formed precipitate is A_mB_n, the condition of c_r≥mc_xV/(nV_r) needs to be satisfied. After an A-selective electrode and a reference electrode are immersed to the sample added the reactant, this solution is titrated with the solution(standard-1) containing A of a known concentration(c_s1), where the added volumes and the final added volume of the standard-1 are denoted with v_s1 and v_s1⁰ respectively. The electromotive forces(E₁) which correspond to added volumes(v_s1) of the standard-1 are measured. Subsequently the same sample solution of volume V and the reactant of volume V_r are added to titrated sample. This solution is titrated again with the solution(standard-2) containing A of a known concentration c_s2(>c_s1) and having the same ionic strength as that of the standard-1. The electromotive forces(E₂) which correspond to added volumes(v_s2) of standard-2 are measured.
If E₁ and E₂ which correspond to v_s1 and v_s2 that satisfy a condition of v_s2=2v_s1-v_s1⁰ are read off from two titration curves, the following equation is held concerning with the concentration c_x of B:
y=(nc_s1/nc_rV_r-mc_xV)x+g
where y=10^ΔE/S, x=v_s1{(c_s2/c_s1)-y}, ΔE=E₂-E₁, and S and g are the response slope of the A-selective electrode and a constant respectively. This c_x is determined from the slope of linear plots of y vs. x.
By using a silver ion as the precipitant and a silver ion-selective electrode as an indicator electrode, concentrations of a hexacyanoferrate(II) ranging from 1×10^-2 to 5×10^-4mol dm^-3 in the samples of various ionic strengths were determined with an error of less than approximately ±1% and a relative standard deviation of less than 1%.

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Properties of dihydroxy[3-(3-mercaptopropanamido)phenyl]borane(1) in the form of self-assembled monolayer on a gold electrode were studied by quartz crystal microbalance(QCM) method. The monolayer of 1 with surface coverage of 7.6×10^-10mol/cm² was obtained by immersing the gold electrode in aqueous solution of 1. The monolayer was found to bind D-fructose reversibly to form sugar/boran complexes in alkaline media. Selectivity of sugars(association constantsK=100, 4000, ≈0 and ≈0M^-1 for D-glucose, D-fructose, sucrose and methyl α-D-xylopyranoside, respectively) was consistent with the previous works concerning homogeneous solution of dihydroxyboranes. Although pH dependence of the sugar-binding ability of the dihydroxyborane in monolayer resembled that in homogeneous solution, the following remarkable characteristics were found for the assembled dihydroxyborane: (1) The dihydroxyborane in monolayer exhibited a greater pK_a value than that in homogeneous solution, which was explained by the interaction between neighboring trihydroxoborates RB(OH)₃^-. (2) The sugar-binding ability of the assembled dihydroxyborane was noticeably sensitive to pH depending on the square of [trihydroxoborate]/[dihydroxyborane] ratio.

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Synthesis of 1, 1-disubstituted derivatives of 2, 5-diphenylsilacyclopent-3-enes and 2, 5-diphenylsilacyclopentanes was investigated.
1, 1-Disubstituted derivatives of 2, 5-diphenylsilacyclopent-3-enes having dialkoxy, 1-alkoxy-1-methyl, 1-alkoxy-1-chloro, and 1-alkyl-1-chloro were prepared by one-pot reaction of(1E, 3E)-1, 4-diphenylbuta-1, 3-diene and dichlorosilanes in the presence of magnesium. 1, 1-Dialkoxy derivatives were obtained in about 80% yield, but 1-alkyl-1-chloro derivatives were obtained under 50% yield. Each silacyclopentenes was given as the mixture of trans and two cis isomers. 1, 1-Dialkoxy derivatives were obtained as a trans rich form and 1-alkyl-1-chloro derivatives were obtained as only cis isomer. Then the hydrogenation of 1, 1-disubstituted derivatives of 2, 5-diphenylsilacyclopent-3-enes by hydrogen gas in the presence of Pd-C gave the corresponding derivatives of 2, 5-diphenylsilacyclopentanes.

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By selectively electroplating on conducting polypyrrole(PPY) patterns which were prepared using the photochemical oxidizing ability changes of an oxidation polymerization agent such as iron(III) chloride, we found that metal fine patterns would be deposited on the face of substrates. By the use of this method, we will construct a novel manufacturing process of a metallic electric circuit board without using a metal foil bonding board as well as eliminating the steps of etching and removing resist. The copper electroplating on the PPY pattern was achieved by the use of normal copper electroplating bath. However, in contrast to on metals, the propagation of the electrodeposit along the surface of the PPY was observed during the electroplating process on the PPY pattern. The copper deposit forms first near the electrical contact, then gradually propagates laterally along the surface of the PPY pattern. We also discussed the mechanism for this propagation of the electrodeposit.

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The performance of thermal dehydrochlorination of PVC has been studied by FT-IR spectroscopy and the analysis of products by GC. The yields of hydrogen chloride reached to almost constant values under the heating conditions higher than 350°C. But the yields of chlorinated organic compounds increased with the decomposition of produced polyene at the temperature higher than 400°C, although their amounts were very small. Therefore it seems that a very small amount of chlorine remains in the residue after the termination of dehydrochlorination. From the FT-IR spectroscopy of residues, the dehydrochlorination rate of isotactic PVC with gauche conformation is lower than that of syndiotactic configuration. The spectrum due to isotactic PVC was slightly observed even in the residue dehydrochlorinated at 400°C for 120min.

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Solid solution of MgSO₄ and Al₂(SO₄)₃ was prepared from mixed aqueous solutions by rapid dry using micro-wave heating. The Mg²⁺ ion is soluble into the anhydrous aluminum sulfate crystal lattice over a wide range up to near the equimolar composition of MgSO₄ and Al₂(SO₄)₃. The anhydrous aluminum sulfate solid solution, at first, thermally decompose into the mixture of η-Al₂O₃ and MgSO₄. The crystalline spinel phase appears at the second step of the thermal decomposition. The lattice parameters of the spinel changes linearly with the Mg content ranging from 0.5 to 0.8 at the fraction of MgAl₂O₄/(MgAl₂O₄+Al₂O₃). The produced nonstoichiometric spinel solid solutions must be metastable because the stable region of the composition of the spinel solid solutions is very narrow at the heating temperature employed to the thermal decomposition.

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Transparent polycrystalline YAG(Y₃Al₅O₁₂) ceramic, optical characteristics of which are comparable to those of a single crystalline YAG, was fabricated by a sintering method using >99.99mass% purity powders and its application to a window material of infrared spectrophotometer was investigated. Its average grain size and pore density were 50μm and about 1ppm, respectively. It showed high strength(modulus of rupture: 350MPa), high hardness(Vickers hardness [HV10]: 1280), low refractive index(1.8 at 590nm wavelength) and low thermal expansion coefficient(8×10^-6K^-1), and was very stable in various inorganic solvents, 10% HF solution, 1M HCl solution, 1M H₂SO₄ solution, 1M NaOH solution and 10% NH₃ solution and organic solvents, methyl alcohol, acetone, toluene and dimethyl sulfoxide. The transmittance of 1 mm-thick YAG was about 85% for the wavelength of <6μm and decreased with increasing wavelength to reach almost 0% at 9μm. These results and some infrared spectral measurements indicate that the present YAG ceramic is a good window material in the range of 2.5 to 9μm.

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