We have found that the cross-linked fully aromatic polyamide reverse osmosis membrane composed of 1, 3, 5-triaminobenzene has high separation performance and high durability. High cross-linking density contributes to high salt rejection (>99.5%) and high durability. We also developed the new synthetic method of 1, 3, 5- triaminobenzene suitable for high performance membrane. We could obtain the high purity 1, 3, 5 triaminobenzene by purification of 1, 3-diamino-5--nitrobenzene and reduction in the presence of Pd/C catalyst. We have newly developed the high flux type membrane fit for brackish water softening, the high salt rejection type one used in ultrapure water production and the two stage reverse osmosis membrane. High flux membrane could be achieved by introducing a hydrophilic group to the membrane materials at in-situ interfacial polycondensation. High salt rejection membrane was attained by reordering of polymer chain by post-treatment. Two stage reverse osmosis membrane introduced tetraalkylammonium salt groups takes the place of the ion exchange tower. These membrane technology based on 1, 3, 5, -triaminobenzene is used especially for ultrapure water production, seawater desalination, trihalomethane separation and so on.

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The alginate is an anionic polysaccharide which is composed of 1-4 linked β-D-mannuronica cid (M)and 1-4 linked α-L-guluronica cid (G) The mannuronic acid/guluronic acid ratio of an alginate molecule effects strongly on the polymer concentration at the gel point in the alginate-acetic acid aqueous solution system. The G-rich alginate forms a gel at lower polymer concentration. This is attributed to the fact that the sequence of guluronic parts is stiffer than that of mannuronic parts. On the respect of gellation by introducing divalent metal ions, the salt concentration required for gelation of alginate aqueous solution increases in the order of SrCl₂< CaCl₂< MgCl₂, and the G-rich alginate aqueous solution forms a gel at lower concentration of added salt. These results correspond to the facts that the affinity of these metal ions for the alginate decreases in the order of Sr²⁺ > Ca²⁺>Mg²⁺, and that the G-rich alginate has a higher affinity for divalent metal ions. The gel structures formed by introducing CaCl₂ or SrCl₂ were also studied in terms of fractal structure using small angle X-ray scattering measurements.

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This paper reports a unified apparatus for measuring transient properties of fluorescence emission by using the single photon counting technique. The apparatus has the advantage of low cost and easy construction.
The time-correlated single photon counting method was adopted for the measurement of fluorescence decay curves. A free running nanosecond light source was constructed, which consists of tungsten spark gap and sealed N₂ gas. Fluorescence lifetimes were determined by the multiexponential fitting of observed decay data under consideration of convolution effects. Time-resolved fluorescence spectra can be measured with the same apparatus; A time analyzer works as a time gate, and output counts of the analyzer were stored on the memory of a personal computer. After scanning the observing wavelengths over a fluorescence band, a time-resolved fluorescence spectrum corresponding to a gated time was recorded on the memory of personal computer. Use of the memory of personal computer removes restriction on spectral range and reduces the cost to construct an apparatus.
The performance of the apparatus was tested with the standard compounds of fluorescence lifetime and the accuracy of the system was found to be better than 0.2 ns.

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The conversion of ethanol to acetone in the presence of water vapor on a CaO-ZnO (molar ratio Zn: Ca = 9: 1) mixed oxide catalyst was studied by perturbation of steady state by small doses of ethanol, acetaldehyde, ethyl acetate, acetic acid, or acetone. Directions of transient pressure responses of the reactants and the products have led to derive the following conclusions: (a) ethanol and acetaldehyde, and also acetic acid and acetone, are relatively rapidly converted to each other; (b) acetic acid, apreceding compound of acetone, is rather slowly formed directlyfrom acetaldehyde and water without interposition of ethyl acetate; (c) ethyl acetate is not an intermediate product of the reaction but formed by the esterification of acetic acid with ethanol.

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Titanium nitride fibers have been prepared by use of sodium alginate. In the first stage, TiO₂ fibers were obtained by heating titanium alginate fibers as a precursor at 500°C in air. In the second stage, TiN fibers were prepared by heating TiO₂ fibers in the N2 gas. The phase and morphology of the fibers were investigated by X-ray diffraction technique (XRD) and scanning electron microscopy (SEM), respectively. TiN fibers were formed above 1100°C. The fibers have porous structure. Heating temperature and time had little influence on the porous structure formed in TiN fibers.

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The decomposition products which precipitated by refluxing the alcoholic solution of bis (acetato)bis (imidazole) copper (II) [Cu(CH₃COO)₂(Him)₂] (1) for 8 h were characterized by the elemental analyses and the magnetic and spectrophotometric data. The product obtained from the 1propanolic and ethanolic solutions of 30∼7.5 mM 1 was [Cu (im)₂]n (2). The methanolic solution of 30 mM 1 gave the same product. When the product obtained from a dilute methanolic solution (10 and 7.5 mM 1) was treated under dried air, [Cu (im) (OCH₃)] n (4b) was obtained, while [Cu (im) (OH)_0.4(OCH₃) _0.6]n(4a)was obtained when treated under ordinary laboratory atmosphere.4b converted to [Cu (im) (OH) ](4c)by the hydrolysis in contact with moisture for a long time. When the product which precipitated from the methanolic solution of 15 mM 1 was treated under ordinary atmosphere, [Cu (im)_1.8(OCH₃) _0.2]n (3)was obtained.3 and 4a are considered to be formed by the hydrolysis of [Cu (im)_1.8(OCH₃) _0.2]n and by the imperfect hydrolysis of 4b, respectively. These polynuclear complexes seems to contain a chain structure consisting of square planar copper units.2 revealed the highest thermal stability among these decomposition products. The process of thermal decomposition of 1 in alcohols was discussed.

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Itaconic anhydride has a unique structure to be utilized as building blocks for the compounds having a quarternary carbon atom. However, very few highly-sophisticated utilization of the compound have not been reported in literatures. We synthesized unsymmetric tetracarboxylic acid (2) by nitric acid oxidation of the Diels-Alder adduct (1), which was prepared from itaconic anhydride and butadiene. Dehydration of tetracarboxylic acid 2 with acetic anhydride gave only monoanhydride, 2- (2-carboxyethyl) -2(carboxymethyl) succinic anhydride (3), which was converted to bis (chlorocarbonyl)-substituted anhydride (4) by using PCl₅. Reaction of 4 with a primary amine such as aniline or ethylamine gave unexpected carbamoyl-substituted imide (5), while reaction with a secondary amine such as N-methylaniline or dimethylamine gave bis (carbamoyl) -substituted anhydride (7). Formation of the carbamoyl-substituted imides by the reaction of 4 with primary amines was considered to take place via bis (carbamoyl) -substituted intermediate (8); one of the carbamoyl moiety of 8 attacked the anhydride moiety intramoleculaly to form the imide ring with free carboxyl group.

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The reactions of arenecarbaldehydes bearing functional groups such as methoxyl, nitro, fluoro, and dimethoxyl groups with 2-t-butoxycarbonyl-1-ethoxy-carbonylethylidenetriphenylphosphorane afforded the corresponding arylmethylenesuccinates. Arylmethylenesuccinates obtained, on boiling with anhydrous potassium acetate in acetic anhydride for a short time, gave the corresponding substituted naphthalenecarboxylates in moderate yields.

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The dimerization of phenyl isocyanate in the presence of pyridine was accelerated under high pressure to give 1, 3-dipheny1-1, 3-diazetidine-2, 4-dione in high yield. The apparent activation volume of this reaction at 30°C was estimated to be - 23 ml/mol. Although 3-methylpyridine and 4-methylpyridine were better catalysts than pyridine, 2-methylpyridine and 2, 6-dimethylpyridine had poor catalytic activity for the dimerization. It shows that the steric hindrance around nitrogen atom of a catalyst influences strongly the catalytic activity for the dimerization of phenyl isocyanate. The selectivity of the dimerization increased with an increase in pressure or amount of pyridine as a catalyst. The trimer of phenyl isocyanate was obtained predominantly if trialkylamine was used as a catalyst, and also the trimer was given as a main product when polar solvents such as acetonitrile were used. A new cyclic transition state was proposed for the dimerization mechanism of phenyl isocyanate under high pressure. Although m- and p-substituted phenyl isocyanate dimerized in good yields under high pressure, the dimers of bulky aryl isocyanates such as o-chlorophenyl and 1-naphtyl isocyanate or alkyl isocyanate such as butyl and cyclohexyl isocyanate were not obtained.

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Dehydrogenative coupling reactions of benzene and toluene were carried out in a reactor with a large temperature gradient, in the temperature range from 1270 K to 1370 K for the former, and from 1000 K to 1150 K for the latter to investigate the characteristics of the reactor, in which thermal diffusion was expected to arise due to the temperature gradient. The reaction of benzene followed a pseudo zero-order kinetics, and the activation energy was 421 kJ/mol, which was much larger than those previously reported (155∼289 kJ/mol) for the conventional reactor which had no significant temperature gradient. The reaction of toluene also obeyed a pseudo zero-order kinetics. The activation energies for the formation of benzyl radicals and tolyl radicals were 349 kJ/mol, and 423 kJ/mol, respectively. These values of activation energy were almost the same as bond dissociation energies of the carbonhydrogen bond, the cleavage of which led to the initiation of the reaction. The small difference between the obtained activation energies and the bond dissociation energies can be accounted for by the assumption that only a few chain reactions occurred in a reactor with a large temperature gradient, because of the rapid lose of thermal energies of benzyl, tolyl, and phenyl radicals, produced by the initiation reactions.

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The characterization of the precipitation in Yamagata prefecture was investigated and discussed. The samples collected in Yonezawa city from May 1990 to Fabruary 1992 on an event basis were analyzed for pH, electric conductivity. (EC) and concentration of major ions (Na⁺, K⁺, NH₄⁺, Ca²⁺, Mg²⁺, Cl^-, NO^- and SO₄^2-). These data were compared with the data for Yamagata and Sakata cities. The ann ual mean pH values of rainfall and snowfall ranged from 4.6 to 4.9 and from 4.5 to 5.1, respectively. The equivalent concentration sum of major ions in Sakata was higher about 4 or 5 times than the one in Yamagata or Yonezawa. It was forecast that a spatial difference in pH value between rainfall and snowfall was owing to washout processes. The equivalent concentration ratio of NO₃^- to nss-SO₄^2- (nss- means nonsea salt) is increasing over three years in every city, and it is suggested that nss-C1- from HC1contribute to acidifying the precipitation, because the monthly mean pH values gradually decreased with an increase in the equivalent concentration of [(NO₃^-+nss-SO₄^2-+nssCl^-)]-[(NH₄⁺+nss-Ca²⁺)].

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Aluminum fluoride, lanthanum fluoride and yttrium fluoride were purified by a solvent extraction and a sublimation or an ion exchange. Trace impurity elements in the materials were determined by a neutron activation analysis. The impurity concentrations were; Fe 53 ng/g, Co 0.11 ng/g, Ni 1.3 ng/g and Cu 0.54 ng/g for aluminum fluoride and Nd < 20 ng/g, Pr < 4 ng/g, Cu 2.2 ng/g for lanthanum fluoride and Nd < 4 ng/g, Pr < 1 ng/g, and Cu 4.9 ng/g for yttrium fluoride. The platinum and gold in zirconium fluoride, aluminum fluoride and barium fluoride and fluoride-glass were determined simultaneously by the neutron activation analysis using 199Au and 198Au radioisotopes. The level of platinum contamination from platinum plate in the zirconium fluoride fabrication was 5360 ng/g. It is found that ultra-trace amounts of platinum affect the transmission loss in fluoride-optical fiber.

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In order to remove impurities (H₂O and/or CO₂) surface defects and improve the surface crystallinity of commercial (100) MgO single crystal, the complex WE/OA treatment was tried, in which substrates were annealed in the oxygen atmosphere after the H₃PO₄ wetetching. The spectra in cathodoluminescence at about 400 nm disappeared almost completely in the specimens by the WE/OA treatment at 1100°C as examined by the measurement of cathodoluminescence for MgO substrates. The halfwidth of X-ray diffraction peak, TEM images and electron diffraction patterns showed a good [100]-orientation of Pt films deposited on MgO substrates by the complex treatment at 1100°C.

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Adsorption-desorption phenomena of organic compounds at a hanging mercury drop electrode were studied by a flow injection method with measuring differential capacity-time curves. Among the various compounds tested 1-octanol and vitamin B₁₂ were studied in detail. It is clear that the adsorption of 1-octanol is reversible and adsorption of vitamin B₁₂ is irreversible. The effect of the electrode potential on adsorption of 1-octanol was great, and the adsorption was pronounced at the potential of zero charge (ca. -0.6 V vs. SCE). A kink was observed in the differential capacity-time curves for vitamin B12, which indicates the orientation of the adsorbed molecules of vitamin B12 forming a condensed film. The differential capacity-time curves for 1-octanol and vitamin B₁₂ are considered theoretically.

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