In the development for alternative to the currently dominating ITO technology, organic transparent conductive films have been demonstrated for some successful. Especially, 3,4-ethylenedioxythiophene (EDOT) is the most intensively investigated monomer in the past decade due to the very high conductivity, transparency, and excellent environmental stability of its polymer (PEDOT). In this work, the author has demonstrated that the realization of direct electropolymerization of water-insoluble EDOT monomer in aqueous media using tandem acoustic emulsification without surfactants. In this demonstration, the tandem acoustic emulsification was conducted with sequential ultrasonic irradiation (20 kHzy → 1.6 MHz → 2.4 MHz), and this technique provided a clear solution containing a few tens nanometer droplets. In addition, electropolymerization in this solution afforded the PEDOT film composed of polymer spheres with a few tens nanometer size range. In addition, packing of these polymer spheres was found to be very high. Smaller size and higher packing of the PEDOT spheres were needed to construct the PEDOT film with high transparency and conductivity. From these results, it can be stated that tandem acoustic emulsification method is suited for development of the PEDOT film with high transparency and conductivity.

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Lignocellulose is one of the most promising materials for biofuel production. However, lignin covering cellulose fiber and microcrystalline cellulose and hemicellulose is obstacle against effective saccharification by enzyme. Therefore in the present study, we employed ultrasonic (US) in ionic liquid for simple and effective pretreatment of biomass, which was needed for subsequent enzymatic saccharification. The saccharification ratio enhanced from 18% to 87% by US treatment for 30 min in [Emim OAc]. This might be attributed to that lignin structure depressed under US irradiation, which eanhanced decrystallization of cellulose and hemicellulose. So enzyme acceptable site increased in cellulose. These results suggested IL/US

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The novel hollow, open-ended, cylindrical shaped cavitation sensor using polymer piezo-film with spatial resolution was developed by NPL (National Physical Laboratory). We think this sensor is very creative and useful work. However, we heard it had defect of short lifetime. Then, we proposed the modificated cavitation sensor with loger lifetime. Our cavitation sensor has also similar clyndrical shape as the NPL cavitation sensor. However, we deposited PZT poly-crystalline film hydrothermally on the outer side of Ti cylindrical pipe and covered with acoustic isolator of closed cell foam sheet on the above mentioned hydrothermally deposied PZT film. The deposited PZT film is protected from acoustic cavitaion by Ti cylindrical pipe and the closed cell foam acoustic isolator. We measured the spatial distribution of acoustic cavitation in a water tank of a sono-reactor oparated at 150 kHz. Furthermore, we estimatied the validity of measured spatial distribution data of acoustic cavitation by comperaring with the light emition pattern of sono-chemical luminescence (SCL) in the sono-reactor in this paper.

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The current study was undertaken to evaluate the effect of sanazole as a sonosensitizer at previously studied acoustic conditions of different pulse repetition frequencies using two cell lines representatives of solid tumors and hematopoietic cancers. Sanazole alone displayed selective cytotoxic effects towards solid tumor-derived cancer cells resulting in complete cell death after 24 hr treatment and enhanced the ultrasound-induced cell killing after 6 hr post-treatment. The enhancement seemed to be mediated by an additive increase in intracellular oxidative stress levels. Sanazole seems to be an efficient cytotoxic agent for the treatment of solid tumors and a promising sonosensitizer under aerobic conditions.

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Chemotherapy is often complicated by toxic side-effect of the antitumor drugs. To overcome this problem, it is necessary that antitumor drugs are effectively delivered to only tumor tissue. The way is drug delivery system (DDS) using liposome as drug carriers. However, traditional DDS can not achieve full therapeutic effect. This is because controlled drug release in the deep position of the body and carrier dynamics are insufficient. To solve this problem, we used ultrasound for controlled drug release and used DNA aptamer for collecting carrier in cancer cells. At the first setout, liposome was modified with thermosensitive polymer as ultrasound stimulus-responsive carrier. This polymer develops phase transition at a lower critical temperature (LCST) and interacts with liposomal membrane. In this study, we made the calcein-loaded thermosensitive liposome (TS-Lipo), and irradiated it with ultrasound. After that, the release of calcein from liposome was measured by the fluorescence intensity with a spectrofluorometer. The results indicated that the release of calcein from TS-Lipo was increased with increasing ultrasound intensity compared to the non-modified liposome.

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Ultrasonic atomization is a very effective way to generate fine droplets. However, it is difficult to measure the atomization rate because the evaporation occurs at the same time. In this study, the atomization rate was estimated and the effect of frequency and solvent properties on droplet generation was investigated. An ultrasonic transducer was installed at the center of the vessel bottom. In order to produce fountain jet without ultrasound, the pump and nozzle were used. It is defined that the difference of mass changes between ultrasound and liquid pump is the atomization rate. The atomization rate increases with decreasing surface tension and viscosity of solvent. The droplet generates after the fountain appears. The number of droplet for 2.4 MHz is higher than for 0.5 MHz.

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Numerical simulations of sonochemical production of BaTiO_3 nano-particles have been performed under the experimental condition of Dang et al. [9, 10]. The results of the numerical simulations have indicated that the particle size distribution under the assumption that only primary particles aggregate with other particles agrees well with the experimental data, while that under the assumption that any particles aggregate with other particles when they collide each other does not agree with the experimental data. It is also shown that larger particles are present when the initial concentration of BaCl_2 and TiCl_4 (they are the same concentration) is 0.1 mol/L compared to the case of 0.4 mol/L. It agrees with the experimental data. The reason is the longer reaction time and lower viscosity for the case of 0.1 mol/L. It is also shown that the equilibration time is longer for the initial concentration of 0.1 mol/L than that for 0.4 mol/L. The effect of the crystal growth is negligible on the particle size distribution under the present condition.

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Intense orange Na^* emission was observed in different spatial locations from blue emission during multibubble sonoluminescence (MBSL) in sulfuric acid. The color change from blue to orange observed along the streamer in the filamentous structure of a bubble cloud in both ultrasonic horn and cleaner. By comparison of MBSL between an ultrasonic horn and a cleaning bath, the locations of Na^* emission were deferent. The Na^* emission, however, may occur at the location where the acoustic pressure was relatively low in both cases. In the ultrasonic horn case, the Na^* emission only appeared less than 30 % ultrasonic power of full range. Therefore, the sonochemical fields by ultrasonic horns may normally utilize cavitation bubbles without Na^* emission.

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This study describes an original view of the expected process intensification (PI) and a methodology for its realization by comparing the history and trends of PI in the world with those in Japan. It is presently thought that PI should be a model-based process design strategy involving technological innovation at the core of green process engineering (GPE) with the aim of a functional quantum leap. From another viewpoint, PI seems to have its rise in aiming at inherently safer processes. Inherently safer process design means a design concept considering inherent safety at the first step of process design. As approaches to inherently safer process design, the strategy of "minimize" is the most important, and it is rephrased as "intensification." Recent trends of PI seem to be systematic integration using innovative process equipments, alternative energy sources, and new process operations from the viewpoints of three categories, which are the on-site system, the utility system and the operation system. There are many concrete candidates of PI technologies, and above all, compact reactors, ultrasonic and periodic operation are especially interesting for us. An example of our research is compact polymerization intensified by unsteady ultrasonic operation. The synergy effect of systematic integration with a compact reactor and unsteady ultrasonic operation is expected.

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50 mL aqueous solutions of Polyethylene oxide (PEO) at 2 g/L were degraded at different frequencies in the range from 19 kHz to 1 MHz with 3 types of apparatus: horn, direct and indirect apparatus. Irradiation experiments were carried out at 20 ℃ and 5 W of dissipated power. Irradiated samples were then evaluated by Ubbelohde at 25 ℃. To suppress the chemical effects, t-BuOH was dissolved at 100 mM into the solution. PEO degraded rapidly at the first five minutes of irradiation then slowing down, approach to a limiting molecular weight, which depends on the irradiated frequency. Polymer degradation is influenced by physical effects mainly in the range from 20 kHz to 1 MHz. That calculated apparent degradation rate constant from data analysis is influenced by frequency is clearly understood. The higher frequency is, the lower physical

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Polymer hydrogels containing carrageenan biopolymer have various functions, which can be used in many fields of medicine, food, the manufacturing product and construction, etc. Recently, we have investigated hydrogel swelling behavior of the crosslinked polymer gels, since, especially, the research example of the gel characteristic by the ultrasound is very interesting and attractive. However, very little of clarification of the ultrasound (US) effect was repointed in view point of properties of bio-hydrogels. In the present research, the influence of US on the properties of κ and t-carrageenan-hydrogels was studied under US exposure. The carrageenan hydrogel solution contained 3g κ or ι-carrageenan in 97ml water was used. In the carrageenan hydrogel solution, the viscosity was measured when B type viscosity meter was used with 60rpm rotation after exposure of 28, 45, and 100 kHz frequency with the US power of 200W. It was found that hydrogen bonds in the hydrogels were broken by irradiating the US.

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Ultrasonic is widely used to disinfect drinking water and wastewater due to its physical and chemical effects on microorganisms. Our observations showed an enhancement of sonochemical reaction by containing TiO_2 photocatalyst (US/TiO_2 method). We also reported the germicidal efficacy of US/TiO_2 method. The aim of this study was to investigate the effect of ultrasonic frequency on the inactivation of Escherichia coli (E.coli) coupled with TiO_2. A TiO_2 nonwoven fabric was used in this study. Ultrasonic waves (36, 100, 300, 500 or 1000 kHz) were used to treat aqueous suspensions of E.coli (10ml). Before sonication, the number of E.coli in suspensions was adjusted to 2.5×10^8 colony forming units (cfu)/ml. At the same power density and the same exposure time, sonication at high frequency (500 or 1000 kHz) resulted in a lower destruction of E.coli than sonication at low frequency (36 or 100 kHz). The destruction of E.coli exhibits pseudo-first-order behavior and the rate constant vary from 1.9×10^<-2> to 3.8×10^<-1> min1 by changing of ultrasonic frequency with TiO_2. The major factor of cell killing was investigated by quantification of OH radical generation, behaving as chemical factor, by using DHBA as an index of amount of OH radical generation. At high frequency the amount of OH radical generation was much greater than the amount at low frequency. The amount vary from 3.1 to 65 μM with TiO_2. Thus at low frequency the hydromechanical shear forces, behaving as physical factor, produced by ultrasonic cavitation are more important for destruction of E.coli than chemical factor, OH radicals. At high frequency, OH radicals have a primary role in destruction of E.coli as observed by the quantitative studies.

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Lignocellulose is one of the most promising biomass for biofuel production. However, lignin covering cellulose fiber is obstacle against effective saccharification by enzyme. Therefore in the present study, we employed ultrasonic (US) for simple and effective pretreatment of biomass, which was needed for subsequent enzymatic saccharification. First, effect of US pretreatment on total soluble sugar ratio was investigated. Moreover, effect of titanium dioxide (TiO_2) addition into US pretreatment on total soluble sugar ratio was also investigated. Ultrasound irradiation caused shock wave and radical generation, and the presence of TiO_2 enhanced more radical generation under US irradiation. So we investigated the effect of radical generation on total soluble sugar ratio. In our experiment, TiO_2 addition enhanced radical generation under US irradiation but had a very small effect on total soluble sugar ratio. This is because the amount of TiO_2 addition might be small for sugar solubilization.

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The valence of arsenic in aqueous solution is usually trivalent or pentavalent, and arsenic mainly forms As(III) as arsenious oxide in the effluent. Compared to the adsorption processes of As(III) using trivalent iron compounds, the adsorption processes of As(V) is easier to handle. The adsorption process of As(III) requires the oxidation from As(III) to As(V) using oxidants. Therefore it is crucial to oxidize As(III) to As(V) with high efficiency. In this study, we performed the removal of As(III) in the aqueous solution using sonochemical oxidation and trivalent iron compounds. We confirmed that the ratio of oxidation As(III) to As(V) became high with increasing irradiation time. In addition, it became evident that the treatment of As(III) solution with ultrasound irradiation in combination with the application of trivalent iron caused residual As concentration in the solution lower than that treated only by the trivalent iron.

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Unsteady ultrasonic irradiation and temperature control are thought to be effective in control of particles in suspension polymerization process. By ultrasonic irradiation in polymerization, particles with large diameter and with a little adhesion of minute particles are observed. In the present study, we propose a feedback operation system where polymerization section and ultrasonic irradiation section are separated. By irradiating ultrasound to a part of reaction solution in the feedback operation, effects of unsteady ultrasonic irradiation on characteristics of generated particles are investigated. As an analytical result for generated particles by scanning electron microscope, the above-mentioned effects of ultrasonic irradiation are also observed in the polymerization with feedback operation. Moreover, the volume of solution under ultrasonic irradiation and the timing of feedback operation are seen to be important operating variables for controlling particle size distributions.

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In this paper, we demonstrate the isomerization of unsaturated dicarboxylic acids during sonication. Almost all trials were carried out under irradiation of 200 kHz, 200W. Before sonication, pure argon gas (Ar) was passed through the reactant solution in order to expel the air. Concentration and volume of trial samples were 10 mM and 50 cm^3, respectively. Fumaric acid and maleic acid made isomerization under sonication each other. So far, isomerization under ultrasonic irradiation was reported. However, additives were needed for isomerizaiton in those reports. In our system, on the other hand, isomerization occurred without additives. Other major products were malic acid, tartaric acid, and succinic acid. To discuss the role of OH radicals, methanol as radical scavenge was added into the solution. Methanol concentration was 100 mM. When addition of methanol was performed, malic acid and tartaric acid could not be detected. In addition, other reaction paths were also considered.

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Oil sands are the mixture of bitumen (heavy oil) and siliceous materials (sand, sandstone). The bitumen content of oil sands is 10-15wt.%. The main industrial processes to extract bitumen from oil sands need treatment with hot water and steam. The addition of chemical agents (alkaline reagent, surfactants) has been investigated to improve the yield of bitumen. These methods consume a lot of energy and increase the environmental burden. The objective of the present work is to study the extraction of bitumen from oil sands using ultrasound irradiation combined with warm water treatment at 45℃, and removes the use of hot water and steam, thereby reducing the energy consumption. A sample of oil sands from Alberta, in Canada was used in this experiment. The suspension of oil sand was prepared by mixing oil sand and sodium hydroxide with distilled warm water in a flask. Then the suspensions were treated by warm water while being sonicated (28kHz, 200kHz) or stirred (750RPM) for 15min. After the treatment, the extracted bitumen floating on the water surface was collected and weighed after drying. Oil sand and the recovered bitumen were analyzed with a thermo-gravimetric analyzer (TGA) under Ar flow. Only sonication at 28kHz showed increase of bitumen extraction rate and purity by increasing irradiation time. This may be due to the effective breakdown of oil sand aggregates. This was partly because ultrasound irradiation increased the surface area of oil sand particles and let to the large contact area with the warm water.

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The effects of ultrasound irradiation on enzymatic hydrolysis of enolesters with and without albumin were examined. In our previous studies, the enzymatic hydrolysis of 2-benzylcyclohex-1-enyl acetate by lipase afforded the corresponding racemic ketone. On the other hand, the reaction with bovine serum albumin proceeded with high enantioselectivity to give the (S)-ketone. In the presense of albumin, enzymatic hydrolysis was accelerated by ultrasonic irradiation. On the contrary, in the absence of albumin, improvement of reactivity could not be observed.

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In order to put the sonochemical processes of wastewater treatment and material processing in practical use, it is necessary to enhance sonochemical reaction rate and develop a large sonoreactor. In this study, we develop the rectangular sonoreactor and the effects of liquid height and flow on sonochemical reaction rate are investigated. The rectangular sonoreactor was made of stainless steel with glass window and the inner dimension were 120 cm in length, 10 cm in width and 30 cm in height. The ten PZT transducers with 78 mm in the diameter were set in line in the reactor. The sample was 0.1 M of potassium iodide (KI). The sample was flowed by using liquid pump. The I_3^- generation rate increased with decreasing liquid height. The observation of luminol solution indicated that the sonochemical reaction field with high intensity was observed near liquid surface. The I_3^- generation rate became higher by liquid flow. It was considered that the sonochemical reaction field became larger due to enhancement of supply of nuclei cavity.

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The ultrasonic velocity of propagation and absorption coefficient characteristic of aqueous solutions of macromolecules are of interested in the field of physical chemistry. Ultrasound (US) absorption in aqueous polyvinyl alcohol (PVA) solution was investigated. The US waves were emitted at three different frequencies of 28, 45 and 83 kHz. The intensity passed through a medium containing PVA, by varying it's concentration in the solution; the intensity that it absorbs was measured. The results showed that at the US at 45 kHz, PVA can absorb the ultrasound, but more studies will need to do, in order to analyze if breakage of the hydrogen bonding occurs.

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In this paper, we demonstrate in a treatment method for suspension contaminated with trichloroethylene (TCE). The objectives of the present work are to study the purifying the suspension contaminated with TCE and the precipitating the fine particles in the suspension using ultrasound irradiation. Suspension and solution were prepared by ion-change water, TCE and green tuff. TCE solution (500ppm) was completely decomposed for 2h sonication in argon atmosphere. And TCE in suspension (500ppm) was also confirmed the completely decomposition at same condition. Compared the decomposition rate of TCE in solution and suspension, the value were almost same. Isoelectric zone of green tuff suspension was 1.4-3.8 in pH. Degradation of TCE generated which was able to be acidified the solution and the suspension to the pH level of the isoelectric zone. TCE purifying and solid-liquid separation of the suspension using ultrasound irradiation was feasible.

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In this study, a novel microextraction technique termed as ultrasound-assisted microextraction (UAME) has been proposed for preconcentration of aluminum from water samples at ultra trace levels prior fluorometric analysis. UAME is performed in two steps based on ultrasonic emulsification and ultrasound accelerated phase separation phenomena. Lower ultrasonic frequencies favor the emulsification of drop of organic solvent into aqueous solution, which leads to an increase in the mass transport process for the analyte and thus the extraction efficiency due to the higher specific area of dispersed w/o emulsion drop. At a higher frequency (2.4 MHz), however, the organic phase was separated completely again within several minutes. It is suggested that the radiation force in the ultrasound standing wave accelerated the aggregation of organic droplets in the high-frequency sonic field. UAME is thus can be taken place in a single closed vessel to avoid unnecessary risks of contamination. In the determination of trace aluminum(III), 500 μL of chloroform was used as extraction solvent with 8-hydroxyquinoline (8-HQ) as extractant. Parameters such as pH, ultrasonic irradiation time and frequencies were optimized. Under the optimum conditions, the target analyte was quantitatively extracted achieving the enrichment factor as higher as 39.9 (recovery around 100 %) for a 20.0 mL water sample, and the linear range, detection limit (S/N = 3), and the relative standard deviations (RSD) were 0-100 ng/mL, 0.3 ng/mL, and 2.6%, respectively. UAME has been successfully applied to the dissolution test of aluminum(III) from commercial aluminum foil.

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It is well known that dicalcium phosphate dihydrate (DCPD) is slowly transferred to hydroxyapatite (HAp) in water. It was found that the transition was promoted by irradiating the ultrasound in the water. This paper reports that transition from DCPD to HAp by ultrasound irradiation in the suspension. DCPD was synthesized by in CaCl_2-Na_2HPO_4-H_2O system reaction, while the ultrasound was irradiated. The frequency of ultrasound was 20 kHz. The temperature of DCPD suspension rose to 80 ℃ by irradiating ultrasound for 15 minutes. This time, DCPD was transferred with the temperature rise to HAp. The formation rate of HAp was speeder than stirring. It was indicated that formed HAp was Ca^<2+>-deficient HAp by measurement of infrared spectra. The Eu/Ca atomic ratio of formed Ca^<2+>-deficient HAp was 1.42 from the result of ICP. By scanning electron microscopy observation, HAp formed by irradiating ultrasound for 15 minutes was length 50nm × width 30 nm.

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Temperature, humidity, and airflow are important factors that influence comfort in our working environments. We focused on ultrasonic atomization as a means to adjust humidity. The water particles generated by the ultrasonic atomization are very fine, and they do not wet the working space. In addition, the water particles generated by the ultrasonic atomization precipitate due to their heavier weight compared to air. Green tuff, the stone produced in Akita prefecture and used as architectural materials has large surface area and shows superior moisture adsorption. The combination of the ultrasonic atomization and green tuff may function as an excellent regulator of humidity in our working environments. Thus, we performed the fundamental experiments on the ultrasonic atomization and examined the role of the ultrasound mist and green tuff on the regulation of humidity.

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Magnetic iron oxide nanoparticles were successfully prepared by a novel reverse precipitation method with the irradiation of ultrasound. TEM, XRD and SQUID analyses showed that the formed particles were magnetite (Fe_3O_4) with about 10 nm in their diameter and that the magnetite nanoparticles exhibited superparamagnetism above about 200 K. The sizes and size distributions could be controlled by the feeding conditions of FeSO_4・7H_2O aqueous solution, and slower feeding rate and lower concentration lead to smaller and more uniform magnetite nanoparticles. The mechanisms of sonochemical oxidation were also discussed. The analyses of sonochemically produced oxidants in the presence of various gases suggested that nitrite and nitrate ions, besides sonochemically formed hydrogen peroxide, contributed to Fe(II) ion oxidation.

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Precision cleanings of stainless steel plates covered with press working oil by using ozone microbubble combined with ultrasound(28KHz, 45KHz or 100KHz, 100W) were investigated in water. Oil removal efficiencies of the sample plates were investigated by using a microscope and a waterdrop contact angle measurering apparatus. From experimental results, effective removals of press working oil from the surfaces of the sample plates by the investigated cleaning mehod were shown to be achieved under the following conditions: ultrasound, 45kHz(100W); ozone concentration, 1.15 mg/L; washing time, 15 min.

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Various metals were used for organic synthesis with ultasonication. Zinc showed the extreme effect for the C-C coupling reaction. Various ketones were reductively coupled to give the corresponding pinacole. Ketones were substituted with methyl, hydroxyl, acetoxy, halogen and amines on the benzene ring. The typical reaction was achieved as follows. Substituted acetophenones were dissolved in THF. The solution was added with TiCl_4 and Zn in THF at 0℃ and the reaction mixture was ultrasonicated under argon. The reaction mixture was added by sodium hydrogencarbonate solution and extracted with ethyl acetate. The ethyl acetate extracts were concentrated in vacuo and the concentrated solution was chromatographed over silica gel and eluted with hexane-ethyl acetate to give the corresponding pinacol. The pinacol changed to the corresponding pinacolone using strong acid, but pinacol did not change easily to pinacolone using ultrasonication with TiCl_4 in short time. In the case of acetophenone, the corresponding pinacol was obtained in 75% for 2h without using ultrasonication, however by using ultrasonication the same reductive coupling reaction of acetophenone was achieved in 90% only for 10 min. When acetophenone substituted with nitro group was used as the substitute, the nitropinacol produced in the reaction was easily reduced to aminopinachol in the reductive coupling. Reductive coupling of fluoroacetophenone showed high yield.

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Ceramic processing, such as nanoparticles synthesis via precipitation, sol-gel method, electrochemical deposition, spray pyrolysis, metallurgy, and so forth, can be stimulated by physicochemical actions of ultrasound. In this presentation, various experimental works on sonoprocess of ceramic materials are divided into the following three categories and reviewed; (i) acceleration of a process/reaction that can proceed (slowly) in the absence of ultrasound, (ii) switching or induction of a process/reaction that does not proceed in the absence of ultrasound, and (iii) alteration/modification in the texture/microstructure of the product. In addition, quite a queer use of weak ultrasonication at a power of milliwatt is introduced. What I named soft sonication treatment significantly enhanced the aging of the starting solutions for precipitation. Experimental evidences were shown in the precipitation of oxalate precursor in ethanolic solution and the Stober synthesis of silica spheres. The author hypothesize that a microscopic inhomogeneity of solutes and solvents is influential upon nucleation, time-dependent for a duration of days, and enhanced by soft sonication.

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We report here naked gold nanoparticles (Au-NPs) synthesized through the sonochemical reduction of [AuCl_4]^- using a high-frequency (950 kHz) ultrasound in aqueous solutions (in the absence of any amphiphiles as stabilizing and capping agents and reductants). In order to evaluate the mechanism on the size and shape determination of naked Au-NPs formed in solutions, we have investigated the effect of sonication time, ultrasound frequency, HAuCl_4 concentration and temperature on the size and shape of the naked Au-NPs. In this work, in particular, the effect of byproducts such as hydrogen (H_2), hydrogen peroxide (H_2O_2), hydrogen chloride (HCl) and chloride ions (Cl^-) produced during ultrasonication on the size and shape of naked Au-NPs were examined. We found that spherical naked Au-NPs with the diameter of 〜20 nm were selectively synthesized from a H_2-purged HAuCl_4 (0.1 mM) aqueous solution while the naked Au-NPs synthesized from an Ar-purged HAuCl_4 (0.1 mM) aqueous solution were multi-shaped, for example, spherical particles, triangular and hexagonal plates and rods. Furthermore, formation of the triangular and hexagonal plates was enhanced with the addition of hydrogen chloride (HCl) and sodium chloride (NaCl) in HAuCl_4 aqueous solutions. This is most likely due to the affinity of chloride ions with gold surface and the resulting specific adsorption of chloride ions on the particular crystal face (e.g., {111} face) of Au-NPs.

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We think that estimation of acoustic cavitation generated in frequency range of MHz is important for safety assessment of ultrasound exposure to human body and tissue. The objective of this paper is to measure the generated active oxygen together with acoustic cavitation by using special acoustic cell and KI oxidation dosimetry at focal point in 1.6 MHz focused ultrasound field and to research relationships between ultrasound exposure condition and the amount of generated active oxygen. We will report experimented results about the duty cycles of ultrasound burst vs. change in peak absorbance at 350 nm that represent color reaction of 13 ion caused by ultrasound exposure. The peak absorbance near 350 nm increased in proportion to duty cycles between 30 and 100 %. However, when the duty cycle is 50, 80 and 90 %, increasing tendency of absorbance saturated. To investigate this cause, we researched about relationship among the temperature of the transducer increased with increase of duty cycles, the dissolved oxygen level in water tank with KI solusion and the generated active oxygen. We will report about these experiments and their results.

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Sonoluminescence pulse width of sodium atom and continuum emissions were observed from NaCl solution in ethylene glycol. The sodium atom emission in ethylene glycol showed multi-peak pulse and single pulse. Single pulse width was measured to be 0.44 ns, which agreed with the pulse width for continuum emission. The multi-peak pulse may be superposition of single pulses. The result of high-speed photography suggests that the cause of multi-peak pulse is due to many daughter bubbles fragmented from a large bubble. High-speed SL movies showed characteristic emission images that support the above speculation.

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