Recently, agricultural wastes such as sawdust, nutshell and woodchips have been considered as valuable resources which makes it possible to produce alternative fuels or valuable chemicals. The pyrolysis process is considered as the most promising and economical process for the conversion of agricultural wastes. In this study, the pyrolysis characteriscits of agricultural wastes have been determined in a TGA and a bubbling fluidized bed. The agricultural wastes are composed of biopolymers which consist of celluse, hemicelluloses and lignins, which were analyzed by elemental analyser. In TGA(TG-2171, Thermo Chan Co.), the effects of rising temperature rate on maximum pyrolysis temperature, pyrolysis status and so on have been determined. The effects of bed temperature, gas velocity, L/D ratio and bed particle diameter on conversion have been determined in a bubbling fluidized bed (I.D. 7.6cm and 80cm high). For the capturing the bio-oil mist, eletrostatic precipitator was equipped at the exit of cyclone. The amount of bio-oil and char decreases with the increase of reaction temperature because an increase of reaction temperature enhances the reaction between oxygen and organic compounds. Increase of L/D ratio slightly incerase the formation of gas product due to an increase of gas residence time in bed materials. Addition of small amount of oxygen changes the composition of pyroligneous acid.

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In aromatic hydrocarbons there are many organic hazards such as polychlorinated biphenyls and chlorinated benzenes. Emissions of such chemicals from environmental protection equipments and other facilities have become a major social issue, and evaluation of toxicity concentration requires methods having both high precision and high chemical selectivity. Recently, development of molecular spectroscopy has enabled us to select aromatic hydrocarbons very rapidly. In particular, the laser ionization TOFMS (Time of Flight Mass Spectrometry) method is expected to be a powerful for on-line, selective and sensitive method. In this report, real-time laser ionization TOFMS measurements were carried out on gaseous aromatic hydrocarbons. The laser ionization method was used resonance enhanced multi-photon ionization (REMPI) with direct introduction of gas into the vacuum chamber. This method for analyzing aromatic hydrocarbons was developed using a pulsed supersonic molecular beam technique. Excitation of monochlorinated benzene at λ = 263.07 nm was found to be effective in the wavelength from 263 nm to 265 nm. Excitation of polychlorinated biphenyls at λ = 266 nm was found to be substantially more effective than at λ=280, 300 or 320 nm. Also, picosecond excitation for polychlorinated biphenyls underwent more efficient ionization (by a factor of over 10) and less fragmentation than nanosecond excitation. The achievable sensitivity for real-time (1 minute) measurement using the laser ionization TOFMS technique was found to be in the pptV range Accordingly, the laser ionization TOFMS technique implies a useful method for the on-line monitoring of aromatic hydrocarbons. In the future we will pursue practical application in the form of a safety management-monitoring device for aromatic hydrocarbons.

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Recently, harmful ion, a large amount of phosphorus is contained in wastewater such as an agricultural effluent. The effluent standard is about determined as 10 ppm or less about phosphorus ion. It is, therefore, desired to develop the effective technology for removing phosphorus ion. Since O atom in phosphorus ion charge into minus, it is considered that these ions can be adsorbed by OH site by hydrogen bonding. From this viewpoint, we try to develop a new adsorbent that can remove the phosphoric acid by utilizing OH sites in FeOOH. We prepared various FeOOH adsorbents and examined the effect of the structure of FeOOH and the operation conditions on the removal performance of phosphorus ion. The FeOOH prepared by vacuum drying at 220°C had a high potential to remove the phosphorus ion below 2 or 3 ppm. Furthermore, it was found that the treatment at 320°C in 18 MPa enabled us recover phosphorus ion as a phosphorus iron composite of recycle material. By examining the structure change in the FeOOH during pretreatment and reaction with phosphorus ion by XRD and FTIR, it was clarified that the state of hydrogen bonding and pore development in FeOOH and the change in dielectric constant of water were a crucial factor for the removal of phosphorus ion. Thus, the proposed method gives a new route to recycle the phosphorus ion as well as to treat wastewater.

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Electronic parts such as magnetic disks, tapes and thin film resistors are produced by electroless nickel plating method.  The plating baths are usually discarded before the performance of these products deteriorates due to overload of the baths.  The plating wastewater contains large quantities of phosphinate and phosphite which are hard to remove by conventional methods such as the precipitation method. However, when these contaminants are converted to the phosphate form, they can easily be removed by the precipitation method as calcium phosphate. Thus, the conversion of phosphinate and phosphite to phosphate by wet oxidation was studied. The influence of initial oxygen partial pressure, total pressure, pH and presence of co-ion nickel on the oxidation of phosphate was investigated.An aqueous solution of 0.1 mol/dm³ phosphinic acid or phosphonic acid was oxidized by oxygen (0-5 MPa) and/or nitrogen at pH range of 1-12.5 at 453 K. Complete oxidation of phosphinic acid to phosphonic acid was achieved in 1 hour in a nitrogen atmosphere. However, oxidation of phosphonic acid did not proceed in the anoxic condition. In the presence of oxygen, the oxidation rate of phosphonic acid increased with an increase in oxygen pressure. However, the rate of oxidation was lower than that of phosphinic acid; 88 % of phosphonic acid was oxidized by a 5 MPa oxygen gas in 12 hours. The oxidation of phosphonic acid was strongly affected by initial pH of solution. At pH less than 3, it was enhanced with a decrease in pH though it did not proceed at pH range of 3-6. In an alkaline condition, it was enhanced with an increase in pH. At pH 11, more than 99 % of phosphonic acid was oxidized in 3 hours. In addition, the presence of nickel in solution enhanced the oxidation of phosphonic acid.

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Lake Sanaru is a eutrophic lake and is occupying the 1st place in the worst ranking in Japan on the COD base. The water quality has not been improved at all, although the water quality improvement projects have been carried out heretofore. The water circulation in the lake is influenced by the tide and the brackish water is maintaining the biodiversity. The purposes of the study are to build an ecological model and to simulate the ecosystem of Lake Sanaru and finally to provide a useful tool to evaluate the cost-effectiveness of a technology improving the water quality. An ecological multi-compartment model combined with the hydrodynamics has been developed. In the hydrodynamic model, the set of equations for the fluid mass and momentum conservation in two horizontal directions are solved by the finite element method using the Galerkin method of weighted residuals. Good agreement has been achieved between hydrodynamic model predictions and field measurements. The result of hydrodynamic simulation is utilized to estimate the inflow and the outflow between ecological compartments and water levels in each ones. The ecological multi-compartment model has two compartments, the upper and the bottom ones. Each one consists of several sub-compartments describing behaviors of zooplankton, phytoplankton, bacteria, detritus, dissolved nutrients and so on. In the upper compartment, the effect of the physically forced by solar radiation, temperature and mixing layer depth is taking into account, while, for the bottom one, the effect of the diffusion of nutrients such as phosphate and nitrogen from the sediment to liquid is considered. The ecological model gave some promising initial results as a management tool to predict the expected reductions for the undesired consequences of eutrophication problem. The goal of this study is building the model which is reliable sufficiently to predict the water quality in the future, nevertheless as simple as possible.

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Most of photoautotrophic microalgal culture is limited by light because light is easily attenuated in algal suspensions. In order to predict the microalgal growth, the spatial light distribution within photobioreactors and the light-dependent algal activity should be understood and mathematically modeled. In general, CO₂-enriched air is bubbled into photobioreactors and the bubbles, as well as algal cells, are able to scatter light. This makes it difficult to obtain high-quality data sets of spatial light distribution and eventually of light-dependent microalgal growth.
In this study, an airlift rectangular photobioreactor was designed and used for kinetic analysis of light-limited growth of green microalga Chlorella vulgaris. Since light was illuminated only into the down-comer where bubbles did not exist, the effect of light scattering by air bubbles was avoided and the growth curves at various photon flux densities could be obtained under well-defined light conditions. It was found that the effect of light on the specific growth rate was successfully explained by the models based on the local photon flux density (LPFD) and local photon absorption rate (LPAR) hypotheses rather than average photon flux density (APFD) and average photon absorption rate (APAR) hypotheses. Using the developed models, the algal growth was satisfactorily simulated at various light-related conditions such as incident light intensity, light path length (size of photobioreactor), surface to volume ratio, and algal concentration. Consequently, the presented models could be used for predicting the light-limited algal growth, if necessary, when further expanded to general cases like bubble-existing system.

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This study investigated the removal of phenol oxidant using chitosan as a water treatment. p-Quinone was used as a model phenol oxidant. The capability of chitosan was kinetically investigated based on the molecular weight (MW) and deacetylation degree (DD). Temperature and pH were also examined as reaction conditions. The molecular weight of chitosan was determined using Viscometry. Chitosan's DD range was determined using colloidal titration. The molecular weight and deacetylation degree of chitosan were 6.42×10²≤MW[g·mol^-1]≤1.24×10⁶, 83.1≤DD[%]≤90.0. p-Quinone was more easily removed by chitosan than other phenols. The half life period was 3.7h, assuming a first-order reaction. The overall reaction rate constant was evaluated in a free suspended separation system. Its level was sufficiently high, yielding an experimental range of MW (3.89×10⁵≤MW[g·mol^-1]≤1.24×10⁶) and DD (83.1≤DD[%]≤88.6). The basic pH range in an aqueous phase was suitable for p-quinone separation. Amino groups tended to remain in basic solutions rather than in acidic pHs. Increasing the reaction temperature to (282≤T[K]≤328) increased the overall rate constants across molecular weights and deacetylation degrees. The activation energy obtained was 45 [kJ·mol^-1]. This suggested that the removal reaction mechanism included a chemical reaction, because the activation energy exceeded that of the physical phenomena.

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The fungal biodegradation of dye solutions using enzyme catalyzed oxidation may be a feasible alternative to conventional biological treatment processes. White rot fungi are considered one of the most promising microorganisms in bioremediation of recalcitrant xenobiotic compounds. The extracellular enzymes, lignin peroxide (LiP) and manganese peroxidase (MnP), from white rot fungi play an important role in degradation of chemical compounds. Recently, enzymatic biodegradation methods and its modifications using membrane process for decolorization are attracting much attention. The membrane allows the reuse of expensive enzyme in wastewater treatment from dyeing process. This technology makes it possible not only degradation but also the recovery of valuable components from effluent streams. In this study, ceramic membrane bioreactor using white-rot fungi for decolorization of dye solutions was studied. The tubular membrane filtration device was used for the ultrafiltration and nanofiltration system. Alumina and zirconia ceramic membrane was applied for filtration of biomass and residual dyes. The decolorizations of dye solutions by a fungus, Trametes versicolor KCTC 16781, were investigated. The function and the activity of the extracellular enzymes for decolorization were examined. The feasibility of ceramic membrane bioreactor using fungal biodegradation to improve permeate flux and separation efficiencies in dye solutions was also studied. The effects of operating parameters of membrane filtration such as type of dye, dye concentration on the flux and rejection were investigated. Conclusively, this ceramic membrane bi

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We used the polysulphone hollow fibers, which were hydrophilized by polyvinyl alcohol with pore of 0.1µm, as the supporter for the immobilization of hydrogen-oxidizing bacteria(Paracoccus denitrificans). The bacteria were immobilized on the surface of the hollow fiber through the medium of polyvinyl alcohol. The fiber module was furnished in the tubular reactor and the artificial ground water containing nitrate nitrogen was introduced to the outer surface of the fiber and hydrogen needed for reduction of nitrate was delivered from the hollow fiber's inner side. The hydrogen-oxidizing bacteria are autotrophic and need only an inorganic carbon and then the rate of multiplication of the microorganism and denitrification rate was maintained adequately at level of 6.0 mg/L of inorganic carbon. The denitrification rate was also maintained high level at the range of pH6.5 to pH9.5. Subsequently we showed the influence of concentration of nitrate nitrogen in ground water on the rate of denitrification. The rate of denitrification at concentration of nitrate in artificial ground water varied from 20 mg/L to 400 mg/L were measured and plotted. The rate was approximated by r = 52.2C^0.79 at the range of the concentration (r : rate of denitrification [mg-N/m²·h], C : concentration of nitrate nitrogen in [mg/L]). It was appeared that the rate of denitrification of autotrophic bacteria such as the hydrogen-oxidizing bacteria was sufficiently high at lower level of the nitrate than the level in heterotrophic bacteria.The bacteria needed the some trace elements such as phosphorous, potassium and magnesium other than nitrate for denitrification. High denitrification rate were attained by the optimization of pH, the level of trace elements, temperature and pressure of hydrogen gas so on. The possibility of application of hollow fiber bioreactor for removal of nitrates in the ground water was shown.

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A disinfecting method has been considered by ultrasonic irradiation of water in the presence of TiO₂. Titanium dioxide in the rutile-granule form was used as a catalyst in order to generate hydroxyl radicals for cell killing. Escherichia coli and Legionella pneumophila were used for kinetically investigation of cell destruction process. Significant decrease in the concentration of viable cells was observed during irradiation in the presence of TiO₂. About 98% reduction in the concentration of viable cells could be obtained in the presence of 1.0 g/ml TiO₂ during 30 min of irradiation, while only 13% reduction was observed in the ordinary ultrasonic irradiation system. The rate of cell killing was higher in the presence of TiO₂ comparing to Al₂O₃. The rate of disinfection was proportional to the amount of TiO₂ used in the irradiated samples. There was no significant effect of cell concentration on the cell-killing rate in the range of 10³ to 10⁷ CFU/ml. Mechanism of cell killing was further investigated by examining the effect of hydroxyl radical (*OH) scavengers. Ascorbic acid, histidine and glutathione were used in the irradiating samples as radical scavengers. The rate of disinfection was decreased in the samples containing these radical scavengers. Also, a continuous irradiating system was devised and applied for high throughput water disinfection process. Contaminated water containing E. coli was disinfected successfully within two hours of irradiation in the continuous system.

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Dyestuffs are often present in industrial wastewaters and can consist of hazardous substances which have a serious impact on the environment and health. The present work shows a system developed to degrades these substances using sonochemical reactions. Ultrasonic frequencies of 118, 224, 404 and 651 kHz and power input values of 20, 40 and 60 W were tested on Rhodamine B and Orange II dyestuff solutions in order to find the best degradation conditions. Ultrasonic irradiation of air saturated solutions produces free radicals that combine and generate hydrogen peroxide; compared to the production of hydrogen peroxide when irradiating water, a decrease was found during irradiation of the dyestuffs solutions, indicating that some of the free radicals were used in the degradation process. Effects of pH, nitric and nitrous acid formation as well as the total organic carbon value (TOC) were also investigated. For ultrasonic frequencies of 224, 404 and 651 kHz, the degradation rates were very similar, however, the 118 kHz system presented a degradation rate for both dyestuffs about one third of the higher frequencies. Rhodamine B solutions decolorized within 2 h of ultrasonic irradiation for all systems with the exception of 118 kHz. In the case of Orange II, except for the 118 kHz system, all solutions were decolorized within 4 h of ultrasonic irradiation. All reactions were carried out at 25°C and the total ultrasonic irradiation time was 10 h.

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This work deals with the evaluation of the performance of discontinuous or sequential batch reactors (SBR) treating sewage, through a process of endogenous biological nitrate reduction. Different operational conditions were undertaken, and the behaviour under the effects of organic shock loading was considered. Three laboratory scale reactors were operated simultaneously, which were fed with artificial wastewater. The substratum was molasses and nitrate, respectively ,as carbon and nitrogen sources. The three reactors were operated during different aeration times (0, 15 and 30 minutes). Sudden changes (shock loading) in organic matter concentration were carried out along the experiment. Thus, influent load was increased threefold in relation to the original concentration. Results showed that SBR reactors responded quite properly to moderate shock loading. With regard to substratum degradation, Nitrate elimination achieved was around 80 %, while denitrification rate was about 0.87 mg g^-1h^-1.

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Groundwater pollutions by nitrates and nitrites have received increasing attention in many locations in the world. The present paper demonstrates that catalytic decomposition of trace amounts of toxic nitrate and nitrite in aqueous phase on a level with drinking water by reduction to molecular nitrogen could be carried out under mild conditions of atmospheric pressure of hydrogen at room temperature. Supported bimetallic catalyst, Cu/Pd/C, revealed excellent activity for nitrates, while single metallic Pd/C was much more effective than bimetallic catalyst for nitrites. Intermediate nitrite accumulated in solution in the decomposition of nitrate on bimetallic Cu/Pd/C, but the nitrite could be removed in situ with great ease in the presence of Pd/C free of Cu. Suspended Pd/C catalysts were highly active for nitrite reduction under vigorous stirring conditions, where the rate was proportional to the reciprocal of particle diameter, signifying the active Pd sites around external surface of the catalyst particle dominate the observed activity. Thus, catalysts should be used in fixed-bed for effective renewal of aqueous substrate at around the particle surface, but fine powders employed in slurry reactor are not adequate due to the pressure-drop at higher liquid-flow rates. Attempts were made in the present work to prepare Pd/C catalysts capable of fixed-bed operations without pressure-drop, employing carbon monolith, activated carbon powders coated on poly- urethane sponge-skeleton and non-porous alumina spheres as support.

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Biomass of reed (Phragmites australis) has demonstrated the favorable potential to be used as a nobel biosorbent for many heavy metals removal from contaminated water. The favorable condition for reed biomass to adsorb Copper, Cadmium, Nickel, Lead and Zinc were found to be in the pH 6.0, 7.0, 6.0, 4.0 and 7.0 respectively. The biosorption of all heavy metals reached equilibrium within 6 h. Alkali-treated reed biomass showed higher in adsorption capacity when compared to acid-treated, washed reed and virgin reed respectively. Adsorption mechanism of heavy metal onto reed biomass was discussed based on scanning electron microscope (SEM), surface area, FT-IR and Zeta potential. In addition, desorption was highly succeeded by using the acid elution of HCl which support the hypothesis that ion-exchange mechanism may take a major part in the adsorption by reed biomass. For the reusability, more than 3 cycles adsorption-desorption process can be achieved. Due to the high elution efficiency, low biomass damage, high regeneration potential and the world-wide availability of reed biomass could be considered reed biomass as an eco-friendly tool to substitute high cost treatment technologies in the future.

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The usage of chicken manures as organic fertilizers is becoming popular as a result of rapid growth in organic farming. Direct application of chicken manures to soils however poses contamination to the environment. Therefore, chicken manures should be transformed to be environmental friendly and easy handling before it can be applied as organic fertilizers. In this study chicken manure was transformed into organic fertilizer by chemical mineralization technique. It involved the mixing of chicken manures with CaO and Ca(OH)₂ subsequently undergone heat treatment. The effect of CaO and Ca(OH)₂ on the solubility of nitrogen and phosporus were studied. The nitrogen content was measured using nitrogen analyzer, whereas phosporus solubility was measured using UV/VIS spectrometer. Results showed that mineralization technique was able to produce soluble phosporus and nitrogen from mineralized chicken manures. CaO and Ca(OH)₂ contributed significant effect on the solubility of nitrogen and phosporus, where more than 80% of nitrogen from chicken manures can be dissolved.

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Utilization of excess activated sludge as a substrate for production of secondary metabolite is one of the possible measures to solve economical and safe disposal of wastewater sludge. Pretreatment of excess sludge is required to promote the microbial production of metabolite. There are few reports on the disintegration method suitable for activated sludge cake. In the present study, mechanical disintegration methods, such as ultrasonic irradiation, freeze/thaw, and micro-bubble expansion are applied to not only activated sludge slurry but also filtrated and dewatered cakes.
The TOC release efficiencies by ultrasonic were comparable to those by freeze/thaw treatments. The micro-bubble expansion gave less TOC release efficiencies but the energy efficiency was the highest. The effectiveness of micro-bubble expansion was preliminarily verified in the cultivation of Bacillus subtitles on sludge-agar plates with and without the treatment.The TOC releases from filtrated and dewatered cakes by the treatments were also evaluated. The TOC release efficiency decreased with decreasing water content of cake. The micro-bubble expansion and thermal treatments gave higher TOC release from dewatered cake. It can be concluded that micro-bubble expansion is high potentiality as pretreatment of activated sludge cake for production of secondary metabolite with using treated sludge as substrate.

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To obtain plated products of high quality, cyanide compounds have been widely used in the electroplating process. An appropriate treatment of cyanide compounds in wastewater is required before the wastewater is discharged due to its high toxicity. In the present work, wet oxidation of cyanide in aqueous solution was studied using a batch type-autoclave. The effects of initial concentration of cyanide, pH, pressure, and temperature on destruction of cyanide were investigated. Wet oxidation was performed at various temperatures (383-423 K), pressures (0.1-2.0 MPa), and concentrations of cyanide (100-5000 mg/dm³ as CN concentration). NaCN and Na₃[Cu(CN)₄] solutions were used as the sample electroplating wastewater. It was found that the rate of CN destruction in NaCN solution increased as the temperature was raised. On the other hand, the destruction rate was almost independent of pressure and initial concentration of CN. When wet oxidation was performed at 423 K and 1.0 MPa for the NaCN solution with CN concentration of 1000 mg/dm³, 99.8% CN was decomposed in 2 hours reaction time. Formic acid (HCOOH) and ammonia (NH₃) were identified as the products in the solution after wet oxidation treatment. It was also found that Na₃[Cu(CN)₄] has a lower percent destruction compared with NaCN in oxygen and nitrogen atmospheres. After wet oxidation in oxygen atmosphere, copper in the Na₃[Cu(CN)₄] complex was generated as copper oxide (CuO) precipitate.

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The biomass of Corynebacterium glutamicum was evaluated for its potential to remove reactive dyes from aqueous solution. Five reactive dyes tested in this study were Reactive Orange 11, Reactive Yellow 2, Reactive Black 5, Reactive Blue 4 and Reactive Red 4. The reactive dyes were effectively removed by the biomass at solution pH ranging from 1 to 3 while little uptake occurred at pH above 6. The maximum uptake of the reactive dyes was in the range of 137-464 mg/g. Biosorption isotherm showed that the biomass had a high affinity to the reactive dyes. Also, the sorbed dye on the biomass surface is easily desorbed under neutral condition, refecting that the C. glutamicum biomass can be repeatedly reused for the dye removal. When considering that the C. glutamicum biomass is much cheaper than commercial adsorbents such as activated carbons and ion exchange resins, this biomass waste is a candidate for cost-effective biosorbent.

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The aim of this study was to investigate the effects of Ni(II) on the activity of activated sludge microorganisms in the sequencing batch reactor (SBR) treatment process. Two parallel lab-scale SBR systems were operated. One was used as a control unit, while the other received Ni(II) concentrations equal to 5 and 10 mg/l. The SBR systems were operated with FILL, REACT, SETTLE, DRAW and IDLE modes in the time ratio of 0.5 : 3.5 : 1.0 : 0.75 : 0.25 for a cycle time of 6 h. The presence of 5 mg/l Ni(II) in synthetic wastewater caused a slight reduction in TOC removal efficiency, whereas 10 mg/l Ni(II) addition significantly affected the SBR performance in terms of suspended solids and TOC removal efficiency. It was found that the addition of Ni(II) into SBR system caused drastic drop in TOC removal rate and specific oxygen uptake rate by activated sludge microorganisms due to the inhibitory effects of Ni(II) on the bioactivity of activated sludge microbes. Termination of Ni(II) addition led to almost full recovery of the bioactivity in microorganisms as shown in the increase of specific oxygen uptake rate and SBR treatment performance.

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The Induced Air Flotation (IAF) by using a new kind of micro-bubble generator is developed as an alternative of Dissolved Air Flotation (DAF). In the micro-bubble generator, the air can be self-aspirated, cut and shattered by the rotating flow in the nozzle. As a result, a large quantity of micro-bubbles whose diameter is about 5∼30µm are discharged from the lower part of the nozzleTo determine the optimum operating conditions, a batch IAF reactor was used and kaolin samples were prepared from jar tests using different alum dosages and flocculation times, while the size of micro-bubbles was controlled by changing the flow rates of the recycle water and induced air.The results of the removal efficiency in the batch experiments show that the IAF has the ability to remove particles from water with a lower concentration of particles. The IAF obtains excellent particle removal efficiency in a wide range of alum dosage and flocculation time. Micro-bubbles are generated at various flow rates of recycle water and induced air. Lower flow rate of air performes better particle remova, whereas lower water flow rate obviously shortens the necessary flotation time.

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Methane fermentation was carried out to produce methane from lignocellulosic waste, i.e. soybean curd refuse, bamboo, and Japanese cedar. Soybean curd refuse was fermented directly using methanogens sludge. Bamboo and Japanese cedar were pretreated by steam explosion and then fermented using methanogens sludge. The steam explosion was effective for the delignification of bamboo and Japanese cedar, and enhanced the methane production from lignocellulosic waste. About 300 mL methane gas was produced from 1 g soybean curd refuse. The maximum amounts of methane gas produced, i.e. 237 and 108 mL, were obtained from 1g steam-exploded bamboo (Steam pressure of 3.5 MPa and steaming time of 5 min) and steam-exploded Japanese cedar (Steam pressure of 3.5 MPa and steaming time of 10 min), respectively. Since about 420 mL methane gas are produced from 1 g holocellulose, according to Buswell's theory, the yield of methane produced from holocellulose in the steam-exploded bamboo (holocellulose content: 0.71 g) and Japanese cedar (holocellulose content: 0.44 g) corresponded to about 80 and 60 % of the theoretical value, respectively.

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We measured the equilibrium isotherm for adsorption of organic acids (acetic acid, malic acid, and citric acid) on crosslinked chitosan fiber at 298K by the batch method. The adsorption of organic acids on a crosslinked chitosan fiber, which was fabricated from chitin, appeared technically feasible. The data of the equilibrium isotherms for adsorption of organic acids were not affected by the initial concentration of the solution, and were correlated well by the Langmuir equation. Adsorption of organic acids on crosslinked chitosan would be caused by the acid/ base neutralization reaction between the carboxylic group of organic acid and the fixed amino group of the crosslinked chitosan. Saturation capacity of the equilibrium isotherm for adsorption of each organic acid decreases as the molecular weight of organic acid increases. Equilibrium amounts for adsorption of organic acids on crosslinked chitosan fiber were affected by the concentration of salt (NaCl) in the liquid phase.

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We are trying to find an application of fullerene to water treatment processes, because price of fullerene is getting much cheaper. In this work, we found that phenol in aqueous solution was oxidized by fullerene under visible-light irradiation. Circulating air bubbled through a flask containing 200 ml phenol aqueous solution and 1 g C60 (70%) - C70 (25%) fullerene after four 100W clear lamps were stabilized. Concentration of phenol was photometrically analyzed by 4-aminoantipyrine method. Several runs at the same condition revealed that phenols decreased monotonically with time. Decomposition rate was correlated as the second order in phenol concentration and the reaction rate coefficient was estimated as 12.1 l/mol h. However, reaction mechanism is thought that a triplet state fullerene exited by visible light transfers energy to an oxygen atom, and excited single state oxygen atoms oxidize to decompose organic substances such as phenol, we have to set up a more reliable reaction mechanism.

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Pressurized biochemical process is a kind of innovative water treatment technology, which is derived from traditional activated sludge process. The major advantage of this method is that oxygen transfer barrier is overcome by increasing dissolved oxygen level. In this paper, high concentration pesticide wastewater treatment by pressurized activated sludge process was experimentally investigated. All results were compared with that by the bioreactor operating at atmospheric pressure. It was found that the removal of chemical oxygen demand(COD) increased steadily with the increase of operating pressure, aeration time and sludge concentration within the range of pressure (0-0.3MPa). 85.0-92.5% COD removal (the effluent COD of 230-370mg/L) was achieved under the operation condition of influent COD 2500-5000mg/L, operating pressure 0.2MPa, and the aeration time of 6 hours. The COD volumetric loading of the equipment is 5.8-7.6kgCOD/m³.d while the COD volumetric loading is 2-2.8kgCOD/m³.d at atmospheric pressure. The COD removal can be described by modified Monod model, with the biochemical kinetics parameters, S_n=122mg/L, V_max=2.31d^-1, K_S=487mg/L.

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The feasibility for removal of Cr species from contaminated groundwater by adsorption onto the Fe(0) nanoparticles has been studied in the present work. Experimentally, the efficiency for removal of Cr(III or VI) was >99.9 % in the range of 1000-15000 mg/L. The morphology and particle size distribution of Fe(0) nanoparticles were confirmed by XRD, FE-SEM/EDS and TEM. By XANES, it was found that mainly Cr(III) with a small amount of Cr(0) was adsorbed on the Fe(0) nanoparticles. This work exemplifies the utilization of XANES/EXAFS and FE-SEM/EDS to reveal the speciation and possible reaction pathway in a very complex adsorption process in detail. It is also very clear that adsorptive decontamination of Cr species via the in-situ remediation by using a reactive permeable barrier of Fe(0) nanoparticles would be environmentally attractive in the future.

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Oscillatory zoning of solid solution of (Ba,Sr)SO₄ was investigated in gelatin. Then, Ba²⁺ and Sr²⁺ diffused into gelatin, and SO₄^2- also diffused into opposite direction. Periodic change of molar ratio Ba²⁺/Sr²⁺, which was firstly found out by Putnis et al., was well reproduced. For elucidation of the details, we investigated effects of gelation time and gelatin concentration on the structure and chemical inhomogeneity of particles. Experiments with 12%-gelatin gave results that core portion of solid solution was composed of BaSO₄, which was easily expected by the thermodynamics. However, we were able to make various kinds of particles with novel structures by controlling gelation time and gelatin concentration. As an example, solid solution in which the core portion was mainly composed of SrSO₄ was obtained. Further, different structures of particles were successfully made in separated zone in gelatin. Then, white turbid zones were clearly separated by a transparent gel. Fine particles with peculiar physical structures were also obtained. These particles were formed spontaneously without special operations. This was achieved by a reaction-diffusion kinetics. Gelation time and gelatin concentration controlled the diffusion rate mainly, which induced dramatic change in particle growth process in gel. However, the diffusion rate cannot explain all of their effects on particle structures and the chemical inhomogeneity Based on these findings, we discussed the mechanism of oscillatory zoning and proposed a new approach for formation of particles with novel fine structures in a single chemical process.

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Adsorption process and order formation of colloidal nanoparticles onto a planar surface are examined. We perform Brownian Dynamics simulations with a three dimensional cell model, in which the particle particle and particle substrate interactions are modeled on the DLVO theory, and examine the effects of the frictional force acting between adsorbed particles and the substrate onto the adsorbed structure formed on the substrate. The results obtained are as follows. When the frictional force is so strong that the adsorbed particles are stuck to the substrate, ordered structures never form, which seems to be quite natural. On the other hand, when the magnitude of the frictional force is moderate, an ordered structure can form even with lower coverage; the frictional force can help order formation. This is because the frictional force restricts the particles' Brownian motion that disturbs the ordered structure on the substrate. Furthermore, through the detailed examination of the distribution of the Brownian motion, the increase in the frictional force is found to play a similar role to the decrease in temperature.

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This paper reports the results of investigations of the reaction behavior and the higher order structure of Rhizopus delemar lipase solubilized in a bis(2-ethylhexyl) sulfosuccinate sodium (AOT) reverse micellar system. In the triolein hydrolysis by lipase, the initial reaction rate depended on the organic solvent used to prepare the micellar phase. The highest rate was obtained in the system prepared with isooctane. In the isooctane system, the initial reaction rate strongly depended on the water content W₀ (= [H₂O]/[AOT]) and was maximal when W₀ = 13. From circular dichroic (CD) measurement, far-UV CD spectra of lipase depended on the organic solvent species, and the lowest ellipticity value was obtained in the isooctane system. The ellipticity values at 222 nm in the isooctane system were changed with the W0 value, increased steeply above W₀ > 13. These results suggest that in the reverse micellar system, the higher order structure of lipase is related to whether the lipase in the system fully expresses its activity.

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To clarify the growth mechanism of polymeric particles in the soap-free emulsion polymerization, the growth process of polymeric particles was observed with molecular scale using atomic force microscope (AFM). The soap-free emulsion polymerization was carried out using 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V-50) as a cationic initiator. The initiator, V-50, enables us to synthesize cationic polymers and polymeric particles and make them adsorb on the negatively charged mica surface with molecular scale smoothness. Hence, the growth process of polymeric particles is able to be observed in situ on mica surface directly by tapping-mode AFM. In the case of polystyrene particles, we succeeded in observing the nucleation process and concluded that PSL particles generated through micellization nucleation process. It was found in this study that the growth mechanism of PSL particles after the nucleation process was composed of the following processes; coagulation, swelling process by the absorption of the monomers, solidification by the polymerization and adhesion of the small particles in the case of rich initiator. As for the forth adhesion process, hard particles which are formed by high polymerization grow with adhesion of tiny particles, which generate through the nucleation in the bulk even in the particle growth period, to their surfaces. Hence, in the case of PSL particle, as the amount of initiator increases, the size of final particles becomes larger.

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The shape and size of barium compound nanoparticle were controlled by utilizing the water-in-oil microemulsion as nanometer-sized reaction fields. The barium chromate particles as model particles were synthesized using the water-in-oil microemulsion. A bundle of the nanowires, chain structure of the nanorods, superlattice structure of the nanodots, and dispersed nanodots were successfully synthesized by changing the liquid-phase concentrations of starting materials. It is main factor that the crystal growth is suppressed by the surfactant absorbed selectively onto the specific crystal faces of barium chromate. Because of hydrophobic interactions between the surface-anchored surfactant chains, the higher order structures were formed by the self-organization of the nanoparticle. Finally, it was emphasized that the supersaturation ratio and the particle-surfactant interaction were important factors for controlling the shape and size of the inorganic nanoparticles.

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Platinum nanoparticles supported on nanoporous carbons have been prepared by carbonization of metal-surfactant-thermosetting polymer composites. A strategy of this method is to utilize organic-inorganic and organic-organic electrostatic interactions. A precursor solution was prepared from H₂PtCl₆·6H₂O (M), surfactant (S), resorcinol (R), formaldehyde (F), Na₂CO₃, ethanol (EtOH) and deionized water. The carbonized products have high BET surface area of 490 m²g^-1. The RF polymer must be negatively charged and interact with positively charged cationic surfactant to form RF/surfactant composites. Pt particles with a diameter of 2 nm were obtained after carbonization at 1073 K. Surfactant molecules must interact not only with RF resin but also with ionic Pt species and inhibit an aggregation of Pt particles.

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Clay suspensions are of great importance in many industrial applications for the advantages of their gelation ability. The synthetic hectorite-type clays such as Laponite XLG are known to form clear dispersions since they comprise high-purity, very small-size crystallites; they are particularly suited for applications involving light. The clay suspension was used as a new application for the matrix of the preparation and the aggregation control of nanoparticles. In this paper, we studied the effect of salt concentration in the solution on the aggregation control of gold nanoparticles. The gold nanoparticles were prepared in an aqueous solution with Laponite XLG clay by the reducing method using sodium borohydride at 298 K. When clay concentration was 0.5 wt%, which was gel state, the aggregation of gold nanoparticles did not observed even in 30 days after the preparation. In addition, the clay gel prevented the aggregation of the gold nanoparticles, even if the salt was added further. The aggregation of the gold nanoparticles, on the other hand, occurred with the elapsed time in 0.12 wt% clay suspension, where clay was sol state. However, if the salt was added in the dispersion of the gold nanoparticles with 0.12 wt% clay, clay particles aggregated and then it prevented the aggregation of the gold nanoparticles.

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Clay/polyurethane nanocomposite was synthesized from the polyol and polymeric 4,4' diphenylmethane diisocyanate (PMDI) modified with the clay by in-situ intercalation process. Silanol group of the clay and NCO group of the PMDI were reacted for 24 hours at 50°C. FT-IR analysis of the clay modified with the PMDI demonstrated that the NCO characteristic peak was observed in the clay after modification reaction with PMDI. From the results of FT-IR and X-ray of the polyurethane nanocomposite, it is suggested that the exfoliation of the clay layers may be due to the reaction of forming polyurethane between the clay modified with the PMDI and polyol. The flexural and tensile strength of the clay/polyurethane nanocomposite with the modified clay showed the maximum values at 3 wt % of the modified clay. The T_g of the nanocomposite decreases with an increase in the modified clay. We suggest that the decrease in the T_g of the clay/polyurethane nanocomposite with the modified clay content may be due to an increase in the chain flexibility of the polyurethane backbone.

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Preparation of nano capsules using reverse micellar system were performed by in-situ polymerization of styrene and divinylbenzene on the surface of reverse micelle. The effect of preparation conditions on the encapsulation rate of water, average diameter and yield of nano capsules were investigated. The average diameter of nano capsules which diameter was ca. 600nm was not affected by the preparation conditions such as surfactant concentration, sodium chloride concentration in injection water, monomer ratio and pH in injection water. The encapsulation rate of water was affected by the surfactant concentration, the amount of injection water and sodium chloride concentration. On the other hand, the encapsulation rate was not affected by the pH in injection water. From this result, it is possible to prepare the nano capsule regardless of pH in the injection water. Finally, it is proven that the high encapsulation rate was obtained when the low surfactant concentration and the low quantity of injection water.

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Zinc sulfide (ZnS) nanoparticles may provide a semiconductor material to be suitable for opt-electronic applications such as a phosphor for a flat panel display. In this paper, ZnS nanoparticles were obtained by the microemulsion system, of which surfactant was bis (2-ethylhexyl) sulfosuccinate sodium anionic surfactant (AOT) or hexadecyl trimethyl ammonium bromide cationic surfactant (CTAB), and their photoluminescence (PL) properties were measured. When the water content of the microemulsion increased, the size of ZnS nanoparticles increased, and then the intensity of their PL increased in general. In the case of large water content, their size and PL intensity increased with the elapsed time. On the other hands, when the molar ratio of water and surfactant was three, which meant low water content, the PL intensity of ZnS nanoparticles increased with time, although their size did not change. The PL intensity of ZnS nanoparticles prepared in AOT surfactant system was higher than that in CTAB surfactant system, when particle size was equal. This might be indicated that the interaction between surfactant ion and ZnS is affected in the PL intensity. The stability of particle growth was also dependent on the surfactant type, even if at the same particle size or water content condition. We also found that the PL intensity of ZnS nanoparticles by the continuous irradiation was different from that by the intermittent irradiation.

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Sub-micron sized particles have attracted much interest in recent years because of their unique properties in physics and chemistry as well as their potential application in industry. In this paper we evaluated two different processing techniques on the preparation of β-carotene dispersions and their influence on the particle size distribution. The present work also studies the influence of various experimental parameters on the size distributions obtained. β-carotene dispersions were prepared from coarse β-carotene crystalline (with or without addition of triolein) as dispersed phase and water containing emulsifier as continuous phase. These two phases were premixed and subjected to treatments using a high-speed bead mill, and a high-pressure homogenizer. The β-carotene dispersions were characterized by low-angle laser light scattering and scanning electron microscopy. The results showed that the dispersions in size, size distribution and shape were strongly affected by the two processing techniques and various experimental parameters. The drastic size reduction of β-carotene dispersions was observed after first 15 min of bead milling (at rotation speed of 2000-4000 rpm) and after one passage through the high-pressure homogenizer at 10-140 MPa. Both high-pressure homogenization and bead milling appear to be suitable for the preparation of β-carotene dispersions. In general, the mean diameter of β-carotene dispersions ranging from 80-1000 nm was observed in this study.

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Fouling or scale deposition often leads to numerous technical and economic problems in industrial plants and domestic equipment by blocking the flow of water or solutions in pipes or limiting heat transfer in heat exchangers. While most contemporary studies are focusing on crystallisation at heat-exchanger surfaces and scaling on nanofilters in desalination plants, very little work has been done investigating scale formation on pipe and vessel walls. A systematic investigation by the authors using a pipe flow system showed that the formation of gypsum scales in pipes was affected significantly by various process parameters such as supersaturation, flow rate and run time. Different coupons were placed in a vertical order in the tubular units for scale deposition, but the scaling degree was proven to depend on the position of the coupons in the system, making it difficult to compare one from another. Thus, an innovative multiple flow pipe system was developed to allow the same conditions of fouling on many different coupons as well as the relatively continuous investigation of the time effects on the scale formation. Some preliminary results were obtained with the newly designed multiple flow pipe system. These results will be compared to those obtained by the conventional flow system used previously.

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As for the particle formation process, it is important both to synthesize nanoscale product and to dry without agglomerating. In this study, we synthesize the nanoscale barium titanate via sol-gel process with titanium isopropoxide and barium hydroxide chemicals. Grinding and stepwise temperature gradient are adjusted during the drying process. Moreover, the effect of different solvents, concentration and aging time are also discussed. The barium titanate powder obtained in this study is about 20∼40nm with 89% yielding. We find that grinding after calcining at 400°C will lead to lower the particle size and sharper particle size distribution. Grinding and stepwise heating will avoid agglomeration. The X-ray diffractometer result reveals that the nanoscale barium titanate synthesized in this study equips crystallinity after calcining at temperature beyond 600°C. After calcining at 800°C, it shows fully cubic perovskite structure without tetragonal phase. It is believed that the barium titanate crystallite size is smaller than critical grain size and results in pure cubic perovskite phase in this study.

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Titania microballoons were prepared by sol-gel process of titanium tetra-2-propoxide in reverse dispersion. Continuous phase was hexane, in which sorbitan monooleate was dissolved as dispersion stabilizer. Dispersed phase was a buffer solution, of which pH was adjusted from 5.0 to 7.0. These phases were mixed and stirred to prepare reverse dispersion. Titanium tetra-2-propoxide hexane solution was added to the dispersion to start reaction, and stirring was kept for 24 h at 30°C. The titania wet gel particles produced were dried in argon at 30°C and calcined at 500°C to obtain titania. The crystalline phase was identified as anatase. It was confirmed that the products were microballoons by scanning electron microscopy. The mean diameter and the wall thickness were measured as 76 and 4µm, respectively. The wall has two-layered structure, suggesting that it was formed by different two mechanisms, film formation and particle deposition. The yield exceeded 80% for 4 h, and the reaction was almost completed for 24 h. The diameter of the wet gel particles decreased as duration increased. This change may be due to escape of by-product 2-propanol from the dispersed phase to the continuous phase. pH of the dispersed phase did not have any significant effect on diameter. From these results and information of DTA/TGA analysis, the gel formation process was interpreted.

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This study was focused on finding the optimum conditions for higher conductivity on a film prepared by nano-sized ATO particle. Tin-doped antimony oxide nanometer particles were successfully synthesized using the solvothermal method in various conditions. In XRD results it was confirmed that the special peaks assigned to SnO₂ dominated at lower temperature of 600°C, while the special peaks of Sb₂O₃ dominated at higher temperature above 800°C. With an increase of calcination temperature, the resistance on ATO nano-sized film decreased. Moreover, the particle sizes also increased with calcination temperature. The average grain size measured from FESEM micrographs, distributed in range from 5.0 nm (at lower temperature) to 50.0 nm (at higher temperature). On the other hand, the shape of ATO particle attained at lower temperature showed spherical type, however it was transferred to the rhombic shape, and finally, it becomes cubic type above 1200°C. In various Sb: Sn mole ratios, the resistance on ATO film decreased with Sb component, in particular Sb: Sn=8.5: 1.5. At this time, the particle size was about 30.0 nm. On the other hand, the XRD patterns were also different with solvent species. When 1,4-butanediol was used, the conductivity of ATO film was better than other samples. Finally, The conductivity enhanced on ATO film, which prepared in alkali condition. Consequently, the more Sn amount has, the more conductivity has at lower temperature (below 800°C), and the more Sb amount has, the more conductivity has at higher temperature (above 1000°C).

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The active material of cathode in Li-ion batteries, LiNi_1/2Mn_1/2O₂, was synthesized by sol-gel and molten-salt methods. The sol-gel precursors of Mn²⁺ and Ni²⁺ were prepared by using polyvinyl alcohol (PVA) as chelating agent and electrochemical properties of the cathode active material were characterized by FE-SEM, XRD and Charge-Discharge Cycler. It was identified from Rietveld refinement of XRD data that layered LiNi_1/2Mn_1/2O₂ materials were synthesized and the Li⁺ and Ni²⁺ ions were coexisted in 3a and 3b sites. Electrochemical cells using LiNi_1/2Mn_1/2O₂ were tested at the voltage range between 2.0 and 4.8 V and at the specific current density of 40 mA g^-1. It was also found that LiNi_1/2Mn_1/2O₂ included acetylene black of 40 wt% showed higher rechargeable capacity than that of 15 wt%.

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By spreading the colloid solution of hydrophobic silica nano-particles on water surface, the self-assembled mono-particulate crystal film could be formed on the water surface. The mono-particulate film formed on the water surface can be easily transferred on the substrate. By adjusting the conditions, mono-particulate film formed on the water surface is subsequently and continuously transferred to a substrate. In the manufacturing process, high-speed and continuous formation is required. In this paper, we examined high-speed and continuous preparation of mono-particulate film on a substrate. The used samples are Stöber silica. The average diameter of silica particles used as the samples were ranged from 0.1 to 0.9µm. The silica particles were treated with alcohol or silane coupling agent to make its surface hydrophobic. Then, the colloid solutions of these silica particles were spread on the water surface. After the water surface was covered with the particle film entirely, the glass substrate which has already immersed into water was withdrawn at a constant speed. During the substrate withdrawing process the colloidal solution was continuously supplied on the water surface. Both the formation of particle film and the film transfer to the substrate were simultaneously taken place. The transferred particle films on the substrate were observed by using scanning electron microscope (SEM). The SEM observations revealed that hexagonal close-packed mono-particulate film was formed on the substrate.

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Spin-coating method is a simple way to synthesize nanostructured silica films. However, the thin films by spin-coating have low thermal stability because the reactions proceed at room temperature. In this study, we have developed a vapor treatment using a silica source for spin-on nanostructured silica films to improve the structural stability. The vapor treatment promotes condensations of silanol groups. The silica wall is densified and hardly contracts under a calcinations process. This indicates that vapor treatments effectively enhance structural stability. We have studied effect of vapor treatments on mechanical strength and hydrothermal stability of the nanoporous silica films prepared from tetraethoxysilane (TEOS)/Brij 30 (C₁₂(EO)₄) mixtures. The results of pressure tests and hot water-resisting tests show that the vapor-treated films exceed non-treated films in mechanical strength and hydrothermal stability. The vapor-treated nanoporous silica films are promising materials as low-k films with high mechanical strength and high porosity.

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The surface modification of nanostructured inorganic silica particles with polymeric material is an area of increasing research activity due to the beneficial properties these materials possess. Controlling the surface properties and mastering its modification at the nanometer scale are critical issues for performances and applications of nanoparticles. The chemical treatment and functionalization of the nanoparticle surface can be used to enhance and/or control the nanoparticle's overall properties for targeted applications such as in microelectronics. In this study, we modified the surface of silica nanoparticles with methyl methacrylate by UV-induced graft polymerization. The polymer grafted silica particles were analyzed using scanning electron microscopy (SEM) and FT-Raman spectroscopy. Substantial increase in average particle size was observed by SEM image analysis after UV-induced grafting of methyl methacrylate onto pure silica particles. FT-Raman spectroscopy and XPS studies of these materials revealed the successful grafting of methyl methacrylate onto the silica surface. The formation of a covalent bonding between the PMMA and silica surface was indicated by FT-Raman spectra. Thermogravimetric analysis of the PMMA-grafted silica particles indicated the polymer content in good agreement with SEM photographs.

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In situ production and surface modification of cobalt oxide nanoparticles and titanium oxide nanoparticles were carried out by hydrothermal synthesis in subcritical and supercritical water condition at 200, 300 and 400°C. In order to modify the surface of these metal oxides, several modifiers as CH₃(CH₂)₅OH, CH₃(CH₂)₄CHO, CH₃(CH₂)₄COOH and CH₃(CH₂)₅NH₂ were examined. By using the Fourier transform infrared spectra for investigation of modified surfaces, it was found that, these modifiers can modify the surface of cobalt oxide nanoparticles. The surface of titanium oxide nanoparticles are also modified by these reagents. Crystalline structure and size of synthesized nanoparticles were studied by using X-ray diffractometer patterns and transmission electron microscopy, respectively.

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Since semiconductor nanocrystal has great potential in biological labeling, the surface chemistry behavior of nanocrystal at liquid-solid interface is of great research interest. To maintain very small (2∼6nm) and narrow distributed (<5%) diameter under certain conditions, it is necessary to coat nanocrystals with appropriate surfactants. However there is little study about the surface replacement reaction kinetics of semiconductor nanocrystals. In this study, it is proposed to analyze the reaction modifying the nanocrystal surface. CdSe/ZnS-TOPO nanocrystal was modified with MUA (mercaptoundecanoic acid) that molecule is generally employed to become CdSe/ZnS-TOPO nanocrystals water-soluble. Some samples were taken at intervals in the modifying process and measured IR spectrum. The quantity of MUA adsorbed on the surface was estimated by the absorption around 1600 cm^-1 that indicated -COO- group amount. We found that, at initial, there were already MUA bond with nanocrystal. We also found that rate determining step is not the MUA absorption but TOPO desorption reaction.

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This work describes a procedure for the fabrication of noble metallic nanowires, such as gold, silver and plutinum. Metallic nanowires were formed and connected to a network structure uniformly covering a 2-dimensional space by carefully controlling the concentration of reducing reagent in the synthetic method for metallic nanoparticles. It is considered that the decrease of the reducing agent, which acts as well as capping agent, reduces the electrostatic repulsion of preliminary nanoparticles, resulting in the fusion of the nanoparticles to form nanowires. In the case of gold, it was also found that gold ions played an important role in forming and stabilizing the shape of gold nanowires. This method for synthesizing 2-D metallic nanowires is simple and expected to be used as a general methodology for the synthesis of other metallic nanowires.

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In this study, the effects of particle size on the monolayer structure of silica nanospheres are investigated by changing the diameters of particles from 10 nm to 100 nm. Suspensions of silica nanoparticles coated on a glass substrate by a bar coater are evaporated to give a monolayer. The structures of the monolayers are observed by scanning electron microscopy (SEM) and quantitatively evaluated in terms of pair correlation function and the Delaunay triangulation. For the comprehension of dominant factors in self-assembling process, the experimental results are compared with the results obtained by simulation. The monolayer of the particles, the diameter of which are 11.4 nm, cannot be fabricated at high coverage corresponding to the particle weight fraction of the suspension. The pair correlation function of the monolayer shows that particles do not contact with each other and are arrayed with a 1 nm gap. A feasible model for the process suggests that hydration force between silica surfaces prevents their contacting, and that particles are arrayed with a constant distance.

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Biocompatible nano particles are expected to be utilized as carrier of functional ingredient in food industry. Usually, the formation of nano particles using mechanical force is highly energy consuming process. However, nano self-assembled nano particles, which are assembled and formed spontaneously, do not need much energy. If nano self-assemblies can be utilized as a carrier of medicine and functional food ingredient, this spontaneously formed nano particles are suitable for protecting them from the inactivation by intense shear stress. We developed biocompatible nano self-assemblies composed of oleic acid and polyglycerin monomyristate (PGMM) in water. This system can be easily prepared by gently mixing these three components. The appropriate compositions to form the nano self-assemblies were presented. Mean diameter of nano self-assemblies was easily controlled by changing the composition of system. It was widely ranging from ca. 20 to 140nm measured by dynamic light scattering analysis. The size increased with the increase of PGMM concentration, when oleic acid concentration was kept at constant. These nano self-assemblies were characterized by transmission electron microscopy, dielectric relaxation spectroscopy and zeta potential measurement. The stability of nano self-assemblies was also examined. The nano self-assemblies in water were stored at room temperature, and the change of size was measured with time. The size did not change during ca. 1 month. This result shows that these nano self-assemblies composed of oleic acid and PGMM in water is very stable. β-carotene can be solubilized in water system using this nano self-assemblies as a semitransparent aqueous solution. Application of these nano self-assemblies would expand to pharmaceutical and food industries.

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In this report, rapid solidification mechanism in spherical silicons has been analyzed by means of the images of SEM(Scanning Electrons Microscope), X-ray pole plots analysis, and the numerical simulations of cooling rate of spherical silicons. We have adopted a jet-splitting method to produce spherical silicons at ultra-high speed(some hundreds of spherical silicon per second). Molten silicon passing through capillary forms jet and the jet is split into droplets by the hydrodynamic instability. The resulting silicon droplets are rapidly cooled and solidified to be spherical silicons. Much of spherical silicons produced by above method were found to be composed of crystalline silicon by Raman spectroscopy. And they were categorized into some groups according to the surface morphology and the cross-sectional image of the bulk. We found that the morphology of spherical silicons can be controlled by some conditions during fabrication and we propose the simple model that the cooling rate of a spherical silicon determines the surface morphology and the structure of the bulk.

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