Out of the studies of utilization of coal fly ash discharged from a coal-fired power station, an efficient absorbent for SO₂ and NO_x contained in the flue gas from the power station has been developed in the Department Research and Development at Hokkaido Electric Power Co., Inc. The absorbent is prepared by hydration of the mixture containing coal fly ash, lime and gypsum, followed by drying. A drytype desulfurization facility using absorbent has been successfully operated in commercial scale since March 1991.
By improving the hydration process, a more active absorbent was developed and named LILAC after the abbreviation of Lively Intensified Lime-Ash Compound. The LILAC absorbent is used in a semi-dry flue gas treatment system. The semi-dry system is being constructed at Huangdao Power Station in the People's Republic of China under the project “Green Aid Plan” of the Agency of Natural Resources and Energy, Ministry of International Trade and Industry.
The utilization of the spent absorbent which is characterized by high abilities for ammonia absorption and solidifying sludge in water has also been studied in terms of recycling the industrial waste. The spent absorbent has registered name “Eco Sand”, and is ready for commercialization as deodorants for pets, shoes and refrigerator, and also as sludge solidification agent.

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In order to make clear the order of the n, π* and n, π* excited singlet states of salicylaldehyde and the shapes of the potential energy curves of isomerization reaction from salicylaldehyde to its proton-transferred structure in the excited and ground states, the molecular orbital calculations were carried out within the framework of the ab initio 6-31G level with the geometry-optimization using the Gaussian 90source program on the FACOM VP-100E computer.
From the present calculations the followin g conclusions were obtained: (1) In the ground state the intramolecular hydrogen bonded salicylaldehyde is most stable. (2) Its lowest excited singlet state is of the n, π* character and the second singlet state is of the n, π* character. The intramolecular hydrogen bond becomes weaker in the n, π* singlet state than in the ground state. The n, π* singlet state of salicylaldehyde with the intramolecular hydrogen bond is higher in energy than that of salicylaldehyde without the intramolecular hydrogen bond. These results suggest that the isomerization from the structure with the hydrogen bond to that without the hydrogen bond may proceed in the lowest n, π* singlet state. (3) The lowest n, π* state of salicylaldehdye is higher in energy than that of the proton-transferred structure. The calculated potential energy curve suggests that the isomerization reaction from salicylaldehyde to the proton-transferred structure may occur through the intramolecular hydrogen bond in the lowest n, π* singlet state, while it may be difficult in the ground state.

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Al-doped SiO₂: Eu phosphors were prepared by alkoxide method. The emission of the phosphor showed a red color with a main peak at 610 nm, and changed into a blue color of 470 nm by a reduction with hydrogen. This suggests that the europium ions were converted from trivalent to divalent by changing the firing conditions. On the other hand, the phosphors without an Al dopant did not emit light after reduction. Structural information on the difference in the emission property was obtained by EXAFS. It was found that the Eu ions in the Al doped SiO₂: Eu were linked to the Al atoms through the Eu-O-Al bonds. The role of the Al dopant was discussed on the basis of the change in the local structure around Eu ions.

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Direct redox potential measurement of HNQ (2-hexadecylthio-1, 4-naphtoquinone) monolayer at the air-water interface was tried by two electrode arrangements. One method was well known horizontal touching method (HT method) in which an electrode directly contacts on the monolayer. The other one was vertical contact method (VC method) in which an electrode vertically contacts on the monolayer at the air-water interface. By the VC method, HNQ monolayer shows two redox peaks at 256 mV and 40mV vs. SCE. The 256 mV peak is assigned the HNQ molecule redox peak and 40 mV one that is not shown in HT method exhibits the lateral electron transfer in the HNQ monolayer. The VC method can detect the lateral electron transfer in the monolayer at the air-water interface.

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A paper chromatographic technique was used to study the physico-chemical effects of detergents for the removal of oily soils from fiber assemblies without mechanical and/or hydrodynamic forces. Using a cellulose filter paper as the fiber assembly for the fixed phase, the R_f' value of oleic acid (OA), oleyl alcohol (OL), squalene (SQ) or cholesterol (CH) as a model of oily soil has been studied in sodium dodecyl sulfate (SDS) solutions as a function of the concentration and temperature.
The R_f' value, a measure of the detergency began to increase at a co ncentration below the critical micelle concentration (cmc) of SDS, ca.1.5, 2.0, 2.5 or 4.0 mM for CH, OL, OA or SQ, respectively, and was larger for higher concentrations to give higher detergency. The SDS concentration necessary to increase the R_f' value to 1 was near the cmc, ca.7.0 mM for OA and OL, and 8.0 and 9.0 mM for CH and SQ, respectively. The higher the temperature, the lower was the SDS concentration needed to increase the R_f' value for OL.
Atlow concentra tions below the cmc, the removal of oily soil is governed by formation of a molecular complex between the oily molecule and SDS.

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Oxidation of CO/H₂ mixed gas on Co₃O₄ catalysts calcined at different temperatures and spinel oxide catalysts such as ZnCo₂O₄, CoAl₂O₄ and Fe₂CoO₄ was conducted to clarify the relation between the activity of CO/H₂ oxidation and surface cobalt species of the catalyst. The rate of the oxidation on Co₃O₄ was evaluated based on first order reaction with respect to the partial pressure of CO and H₂. The rate constant of the H₂ oxidation per surface area was identical regardless of the calcination temperature of Co₃O₄. On the other hand, the Co₃O₄c atalysts which were calcined at lower temperatures showed higher activities and selectivities for CO oxidation. Among the substituted spinel oxides containing cobalt, ZnCo₂O₄ showed the highest activity and selectivity for CO oxidation. CoAl₂O₄ and Fe₂CoO₄ showed lower activity for CO/H₂ oxidation compared with Co₃O₄. The XPS results showed that the predominant species on Co₃O₄ surface were divalent cobalt ion in tetrahedral coordination and trivalent ion in octahedral coordination. The predominant ones on ZnCo₂O₄, CoAl₂O₄ and Fe₂CoO₄ are trivalent ion in octahedral coordination, divalent ion in tetrahedral coordination and divalent ion in octahedral coordination, respectively. It was concluded that the main factor determining the activity and selectivity for CO oxidation in the presence of H₂ was the trivalent cobalt ion in octahedral coordination on the surface of the catalyst.

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Well-formed crystals of fluorapatite [Ca₅F(PO₄)₃] were grown from KF flux. The solubility of fluorapatite in KF was also investigated. About 16 mol% fluorapatite was dissolved in KF at 1200°C. The solubility decreased gradually with decreasing temperature. The Ca₅F (PO₄)₃-KF system had a eutectic temperature of 745±10°C. The eutectic composition was considered to be approximately 7 mol%Ca₅F ( PO₄)₃-93 mol% KF. Crystal growth of fluorapatite was conducted by heating mixtures conta ining 15 and 20 mol% solute at 1200°C for 10 h, followed by cooling to 600°C at a rate of 5°C h-1. Grown fluorapatite crystals were up to 12 x 2 mm in size, colorless, and transparent. The crystals had the form of hexagonal prism {1010} with pyramidal end faces {1011}. The lattice parameters a and c were 9.369±0.001 and 6.884±0.001 Å, respectively. The density of crystals, pycnometrically determined, was 3.19±0.02 g cm-3. On the other hand, colorless and transparent crystals (up to 4 x 1 mm in size) of fluorapatite were also grown from CaF₂ flux. The disadvantages of CaF₂ flux were the use of higher temperatures and the difficulty in the separation from the grown crystals. It was found that KF was a suitable flux to grow fluorapatite crystals.

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Selective preparation of dialkoxobis (acetylacetonato) zirconium from tetrakis (acetylacetonato) zirconium, Zr (acac)₄, have been investigated.
In the presence of methan ol as an additive, Zr (acac)₄ reacted with 2 molar amounts of sodium methoxide in cyclohexane to afford selectively bis (acetylacetonato) zirconium dimethoxide, (acac)₂Zr (OMe)₂, in a high yield. However, in the reactions using benzene and tetrahydrofuran as a solven t, (acac)₂Zr (OMe)₂ and tris (acetylacetonato) zirconium monomethoxide were formed as the r eaction product. Similar products were also isolated in the reactions using crown ethers as an additive.
The ligand exchange reactions between (acac)₂Zr(OMe)₂ and short-chain alcohols (C₃ and C₄) were studied in benzene. The corresponding bis (acetylacetonato) zirconium dialkoxide, (acac)₂Zr(OR)₂, was produced from the reactions in high yield.

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On the production of polyacrylonitrile (PAN)-based carbon fibers, oxidation conditions of the precur sor PAN fibers govern not only the performance but also productivity of the fibers. The effect of stres due to shrinkage during oxidation of the precursor PAN fibers containing methyl acrylate (MA) was in vestigated on the tensile properties and productivity of carbon fibers. The effect of the addition of ten sion on fibers was also studied. The change of shrinkage stress during oxidation was devided into three regions; the shrinkage stress of fiber increased up to about 120°C (region I -1), decreased to minimun value up to about 240°C (region I -2) and then increased again to equilibrium value during ox idation (region II ). From the measurements of crystallite orientation and tensile strength, the region I was estimated to be owing to the structural change in PAN fibers and the region II to be owing to oxida tion of PAN fibers. The stress behavior depended strongly on the precursor fibers. In order to get car bon fibers with high tensile strength under high productivity, it was preferable to oxidize the precursoi with 2 wt%MA under high tension in the region I -2 and II, where the fibers were stretched at regiox I -2 and shrunk at region II without tension.

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Oxidation conditions of the precursor polyacrylonitrile (PAN) fibers govern not only the performance but also productivity of the PAN-based carbon fibers. Here, the stabilization index (SI) was proposed to be a measure of the oxidation of PAN fibers. The SI was defined as the ratio of the shrinkage stress at 180°C after cooling to that at a high temperature up to which the samples was heated. The content of the chemically-bound oxygen in the oxidized fibers and the tensile strength of the carbon fibers were measured as a function of the magnitude of SI. The experimental results indicate that SI is an effective parameter to determine the optimum oxidation conditions of PAN fibers which finally give carbon fibers with high tensile strength. It was also shown that two step oxidation method in the atmosphere composed of equal volumes of oxygen and nitrogen was preferable to produce carbon fibers.

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Atmospheric sulfate deposition varies markedly with season along the coast of Sea of Japan where the northwesterly wind dominates in winter. The sulfur isotopic ratios (δ³⁴S) of the sulfate have been measured over 7 years in Niigata Prefecture, Japan, in order to investigate the sources of sulfur in the deposits. Remarkable seasonal variation of δ³⁴S of the sulfate (0-12‰9) indicates that contribution of seasalt sulfate is very high in winter and that relative contribution of different sulfate sources to nonseasaltsulfate in the deposits varies with season. Sulfate produced by coal combustion in China has high contribution (20%) in winter, whereas other sulfur sources such as volcanic gases, local anthropogenic sources and biological production become significant in other seasons.

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The adsorption of CFC-11, 12, 13 and 113 on NaY, KY and CsY zeolites was caned out by use of a conventional static adsorption apparatus and the data were discussed in terms of the best fit isotherms. An inflection point was observed on each experimental isotherm at the adsorption amount of ca.1.5molecules per unit cavity. The heat of adsorption calculated by Clausius-Clapeyron equation between 0 and 25°C on NaY zeolite increased with increasing adsorption amount of CFC-11, 12 and 113. These data were explained in terms of the equations proposed by Hill and Kieselev. t Adsorption and Desorption Behavior of Chlorofluorocarbons. I.

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In order to reuse water from cyanide waste water, the copper cyanide waste water is oxidized using ozone with ultraviolet (UV) radiation. The waste water processed by ozone oxidation is passed through a cation exchange resin column and then an anion exchange resin column. The advantage of the process of cyanide oxidation by ozone is that, unlike the conventional chlorination method, it does not produce salts or chloride, which would have to be removed later to reuse the water, because excess ozone decomposes merely into oxygen.
At the process of the ozone oxidation combined with UV radiation, cyanide ion (CN^-) was oxidized to cyanate ion (CNO^-) in a short time without addition of any other chemical. The reaction rate was about three times as fast as the oxidation reaction by ozone without UV radiation. At the process of cation exchange, sodium cation of sodium cyanate was replaced by H⁺. The cyanate ion is decomposed into CO₂ and NH₄⁺ by hydrolysis under acidic conditions. Ammonium ion was absorbed by the cation exchange resin.
The e lectric conductivity of the effluent from the anion exchange column was smaller than 10/μS/cm. No cyanideds, cyanate ion or copper ion were detected in the effuent. This deionized water can be reused as rinsing water in the plating processes.
On the basis of this experiments, we devised a practical recycling system where water of toxic cyanide waste water can be reused as deionized water in the plating processes. Saturated ion exchange resins, the only by-products of the system, are regenerated at a separated place on an industrial scale. This recycling system will reduce a burden on the earth environment and could possibly create economical effect at the process of production.

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In this report, improvement of a photoinduced fatigue phenomenon of a monolayered organic photoconductor (OPC) due to the photochemical reaction product of a carbozolecarbaldehyde hydrazone derivative used for charge transport material is discussed. Inhibition of the photochemical reaction with UV light is effective. The addition of UV light absorbent and quencher of the photo-excited state ene rgy of the hydrazone compound into the monolayered OPC were examined. Results show that both UV light absorbent and energy quencher were effective for the improvement of the fatigue and do not lower much the photosensitivity of the monolayered OPC. In our monolayered OPC, ULA and FH (see formulae)are recommended as UV light absorbent and energy quencher, respectively. In the latter case, the amount required is smaller. The large quantity of the addition of UV light absorbent makes the softening point of monolayered OPC film lower. As the OPC film having lower softening point is not desirable, the improvement of photoinduced fatigue by the addition of energy quencher is superior of the improvement by the addition of UV light absorbent.

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On the basis of the frontier molecular orbital theory, the formation scheme of C₆₀ from napthalenes is proposed. The proposed scheme agrees with the experiment by Taylor et al. Our theoretical procedure is a useful guide to select reagents which are suitable to synthesize a fullerene by the pyrolysis.

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