Language：English   Publishing type：Research paper (scientific journal)  

Radio frequency alternating electromagnetic field enhanced tetraruthenium polyoxometalate electrocatalytic water oxidation

Authorship：Lead author,　Corresponding author   Publishing type：Research paper (scientific journal)  

This study demonstrates the efficient microwave “ultra-rapid” pyrolysis of bamboo using a spatially separated electric- (E-) and magnetic (H-) field and microwave reactor equipped with a semiconductor generator. The microwave E-field promoted the gasification and carbonization of the bamboo within 30 s. Extensive formation of gases (mainly H2 and CO) and tar (fragments of guaiacyl and syringyl lignin) was achieved by E-field heating. However, microwave reflection became prominent after extensive carbonization of the bamboo under a microwave E-field. The carbonized bamboo was more effectively heated in the H-field, which was effective in preventing microwave reflection and yielding biochar with more defects and an amorphous structure than the electric furnace. We also achieved process intensification by employing a higher quality–factor (Q-factor) cavity resonator (915 MHz). The continuous-flow H-field microwave heating reactor effectively improved the carbon content of the pyrolyzed biomass. A synergistic use of microwave E- and H- fields enables the intensification of microwave “ultra-rapid” pyrolysis of lignocellulosic biomass.

DOI： 10.1016/j.cej.2024.156260

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACS Omega  

Ulva sp. is a type of green algae and is widely distributed in coastal areas around the world due to eutrophication. Effective utilization of Ulva sp. is expected for the establishment of carbon-neutral biochemical production. Microwave-assisted hydrothermal extraction is one of the most efficient ways of extracting highly functional polysaccharides called ulvan. Here, we demonstrate the importance of microwave frequency in enhancing ulvan extraction from Ulva meridionalis. We found that microwaves (2.45 GHz) selectively heat water solvent, while radio frequency (200 MHz) selectively heats ionic ulvan. Moreover, 2.45 GHz was more effective for extracting ulvan than 200 MHz. Then, we analyzed the conformational change in ulvan during microwave irradiation using in situ small-angle X-ray scattering. Microwaves initiated the loosening of ulvan bundles at temperatures lower than those of conventional heating. As a result, microwaves at 2.45 GHz selectively heat water and initiate ulvan structural change to enhance the extraction of ulvan from U. meridionalis.

DOI： 10.1021/acsomega.4c04080

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Language：Japanese   Publisher：Japan Society of Colour Material  

<p>Microwave heating is one of the key technologies for new chemical processes that effectively utilizes the renewable energy. Microwaves are capable of highly efficient heating due to direct heating of materials; thus, efficient biomass conversion can be achieved. Microwave is also expected as a tool to control chemical reactions, because microwaves heat the materials in a non-contact mode and induce chemical reactions. This paper introduces examples of biomass conversion processes, such as extraction using hydrothermal reactions, catalytic hydrolysis reactions, and rapid pyrolysis reactions of lignocellulose, that exploit the unique heating behavior of microwaves.</p>

DOI： 10.4011/shikizai.97.171

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACS Omega  

A sintered lunar regolith is expected to be used to construct buildings, roads, and landing pads for spacecrafts on the Moon. Here, we demonstrate that focused microwave heating is effective for the rapid solidification of the lunar regolith simulant to obtain regolith gravel without any microwave susceptor. The conventional multimode microwave oven cannot heat lunar regolith simulants and requires microwave susceptors such as silicon carbide (SiC) and thermal insulators because of its low dielectric loss. We achieved rapid microwave heating of a lunar regolith simulant without using a susceptor or thermal insulator by forming an intense microwave electric field using a cavity resonator and a semiconductor microwave oscillator. Focused microwaves at 2.45 GHz produced the gravel-shaped and solidified lunar regolith at 300 °C lower temperature than a conventional electrical furnace, where more than 1050 °C temperature was required to sinter the lunar regolith simulant. In addition, we produced larger gravel of the lunar regolith simulant using 915 MHz. The intense electric field generated by the single-mode resonator promoted the solidification of the lunar regolith simulant without any additional substances. This process enables the local production of structured lunar regoliths on the Moon without the transport of any materials from the Earth.

DOI： 10.1021/acsomega.4c02702

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Language：Japanese   Publisher：Japan Society of Electromagnetic Wave Energy Applications  

2023年8/31(木)-9/1(金）の日程で、福岡国際会議場および九州大学伊都キャンパスにおいて、「第6回JEMEA若手サマースクール～マイクロ波化学入門セミナー」が開催された。九州地方を中心に、マイクロ波化学の基礎について、網羅的にダイジェストする企画であり、特に若手向けのマイクロ波基礎講座を志向して企画された。

DOI： 10.32304/jemeabulletin.9.1_25

CiNii Research

Language：Others   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acs.jpcc.3c03078

Language：Japanese   Publisher：Editorial Board of Foods & Food Ingredients Journal of Japan  

Algal biomass, called blue carbon, is attracting attention as biomass that is capable of fixing CO₂ rapidly. Fast-growing green algae such as Ulva meridionalis are expected to be used for CO₂ fixation and for bioremediation of eutrophic sea areas. U. meridionalis rapidly assimilates CO₂ as a sulfated polysaccharide called "ulvan". Microwave-assisted extraction processes can achieve efficient extraction of ulvan. Furthermore, ulvan can be efficiently converted to monosaccharides by using microwave heating and polyoxometalates as an environmentally benign superacid catalyst. The sulfated structure of ulvan was effective both for collection of microwave energy and for efficient extraction and conversion of ulvan by microwaves. Rapid CO₂ fixation by U. meridionalis and effective utilization of ulvan by microwaves represents a new carbon-neutral chemical process based on algal biomass.

DOI： 10.34457/ffij.228.2_155

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Language：Japanese   Publisher：Japan Society of Electromagnetic Wave Energy Applications  

The 4th Global Congress on Microwave Energy Applications (4GCMEA) 2022が、中国 四川大学 Kama Huang先生が実行委員長となり、2022年8月17日～20日にオンラインで開催された。本会議はChina Association of Microwave Power Application (CAMPA) が母体となって、2020年に成都で開催される予定であったが、コロナ渦において2年の開催延長ののち、完全オンラインでの開催となった。

DOI： 10.32304/jemeabulletin.8.1_14

CiNii Research

Language：Japanese   Publisher：Japan Society for Bioscience, Biotechnology, and Agrochemistry  

<p>マイクロ波照射により，物質高選択的に熱的非平衡反応場を形成し，化学反応を促進することができる．本稿では，マイクロ波が触媒反応を加速する機構の解明と，環境に調和した新化学プロセスへの応用研究について紹介する．</p>

DOI： 10.1271/kagakutoseibutsu.60.272

CiNii Research

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1039/D2TA01602H

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1246/bcsj.20210401

Language：Others   Publishing type：Research paper (scientific journal)  

Microwave (MW) heating promotes various reactions catalyzed by supported metal nanoparticles (NPs); the mechanism is based on selectively heating the NPs, thereby inducing hot spots at the active reaction sites. Here, we demonstrate the effects of the sizes and loadings of platinum (Pt) NPs supported on single-crystal metal oxide (MOx) substrates (Al2O3, MgAl2O4, TiO2, SrTiO3) having different relative permittivities and conductivities. Considerable heating occurred when Pt NPs were deposited on MOxsubstrates having low relative permittivities and conductivities, indicating that the MW transparency of the substrate is the most critical parameter. Magnetic field heating was preferred when the loading amount of Pt NPs was large. Electromagnetic field simulations suggested that the electric field concentration between Pt NPs formed local hot spots. Moreover, the MW absorption behavior of the NP/MOxcomposite depended on the conductivity of the supported metal, and the frequency of the MWs. We conclude that the relative permittivity and conductivity of the MOxsupport are the most important parameters for ensuring efficacious MW heating by Pt NPs, followed by size and loading of the supported metal NPs. The synergistic effect of the metal NPs and MOxsupport results in targeted MW heating of the supported metal catalyst.

DOI： 10.1021/acs.jpcc.1c06650

Language：Others   Publishing type：Research paper (scientific journal)  

Interfacial Schottky barriers can impact the catalytic function of Pt on TiO2. Since the electronic structure is characteristic of each material, it may be advantageous to tailor the interfacial Schottky barrier by the addition of adsorbed layers. Here, we show that the Schottky barrier in Pt/TiO2can be mitigated by the insertion of self-assembled monolayers (SAM) of carboranethiols that possess an oriented dipole moment. A Pt substrate with the SAM on which TiO2nanoparticles are deposited is used to that effect. Kelvin Probe Force Microscopy shows thatm-9-carboranethiolate SAM with perpendicular dipole moments decreases the potential difference between TiO2and Pt by ∼0.3 eV due to the interfacial electric field of the SAM. Our findings open new opportunities for tailoring interfacial electronic structures not only in the metal-semiconductor junction, but also the semiconductor heterojunctions.

DOI： 10.1021/acs.jpcc.1c00993

Language：Others   Publishing type：Research paper (scientific journal)  

Chemical reactions performed under microwave irradiation often demonstrate high reaction rates, high selectivity, and low reaction temperatures, which allows for more compact reactors and more energy-efficient processes than used in conventional heating methods. In this study, we discovered a new chemical reaction and proposed a new material synthesis method, performed using a solid-state microwave source with an oscillator and a single-mode cavity. We developed a microwave heating thermogravimetry apparatus to confirm that microwave irradiation reduced the temperature of the reduction process. Next, we applied this apparatus to the reduction process of copper oxide with carbon as the reducing agent and compared microwave heating with conventional heating. We demonstrated that the reduction temperature of microwave heating was 192 °C in a magnetic (H) field and 265 °C in an electric (E) field, which were lower than those of conventional heating. For microwave heating in the E-field, plasma strongly affected the reaction process, leading to a reduction in the reaction temperature. For microwave heating in the H-field, localized heating occurred and the average reaction temperature was lower. Using the obtained results, an applicator suitable for these modes can be designed, enabling a reduction process with an additional energy-saving effect.

DOI： 10.1063/5.0050907

Language：Others   Publishing type：Research paper (scientific journal)  

© 2020 American Chemical Society. Microwaves (MWs) are often used to enhance various heterogeneous catalytic reactions. Here, we demonstrate real-time monitoring of a catalyst's oxidation state in a microwave catalytic reaction using a resonance frequency. The changes in the catalyst's oxidation state during the reaction induced changes in the resonance frequency in the cavity resonator. The resonance frequency was not affected by 2-propanol adsorption, while the frequency decreased with the reduction of WO3 → WO3-x. That is, the redox state of the WO3 catalyst could be detected using the resonance frequency. The oxidation state of the WO3 catalyst was then directly observed by the resonance frequency during the dehydration reaction of 2-propanol by microwaves as a model reaction. Resonance frequency monitoring revealed that the enhanced dehydration of 2-propanol by microwaves was attributable to the reduction of the WO3 catalyst. Moreover, the temporal changes in the oxidation state of the WO3 catalyst detected by the resonance frequency coincided with that observed by operando Raman spectroscopy. Therefore, real-time resonance frequency monitoring allowed facile detection of the bulk catalyst oxidation state under microwaves without using any spectroscopic apparatus.

DOI： 10.1021/acsomega.0c04862

Language：Others   Publishing type：Research paper (scientific journal)  

© 2020, The Author(s). The high growth rate of Ulva seaweeds makes it a potential algal biomass resource. In particular, Ulva meridionalis grows up to fourfold a day. Here, we demonstrated strong carbon fixation by U. meridionalis using 13C stable isotope labelling and traced the 13C flux through sugar metabolites with isotope-ratio mass spectrometry (IR-MS), Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), 13C-nuclear magnetic resonance spectrometry (13C-NMR), and gas chromatography-mass spectrometry (GC–MS). U. meridionalis was first cultured in 13C-labelled enriched artificial seawater for 0–12 h, and the algae were collected every 4 h. U. meridionalis grew 1.8-fold (dry weight), and the 13C ratio reached 40% in 12 h, whereas 13C incorporation hardly occurred under darkness. At the beginning of the light period, 13C was incorporated into nucleic diphosphate (NDP) sugars in 4 h, and 13C labelled peaks were identified using FT-ICR-MS spectra. Using semiquantitative 13C-NMR measurements and GC–MS, 13C was detected in starch and matrix polysaccharides after the formation of NDP sugars. Moreover, the 14:10 light:dark regime resulted into 85% of 13C labelling was achieved after 72 h of cultivation. The rapid 13C uptake by U. meridionalis shows its strong carbon fixation capacity as a promising seaweed biomass feedstock.

DOI： 10.1038/s41598-020-77237-1

Language：Others   Publishing type：Research paper (scientific journal)  

© 2020, The Author(s). Scandium is being explored as an alloying element for aluminium alloys, which are gaining importance as high-performance lightweight structural alloys in the transportation industry. Sc-rich ScAlN thin films show strong piezoelectricity and can be fabricated on a hard substrate for use as wideband surface acoustic wave filters in next-generation wireless mobile communication systems. However, the use of ScAlN thin films in microelectromechanical system devices is limited by the high cost of metallic Sc, which is due to the difficulty in smelting of this material. Here, we propose a novel microwave irradiation process for producing Al-Sc alloys, with Mg ions as a reducing agent. Although scandium oxide is thermodynamically stable, intermetallic Al3Sc is obtained in high yield (69.8%) via a low-temperature (660 °C) reduction reaction under microwave irradiation. Optical spectroscopy results and thermodynamic considerations suggest a non-thermal equilibrium reaction with the univalent magnesium ions excited by microwave irradiation.

DOI： 10.1038/s41598-020-59664-2

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© 2020, The Author(s). Microalgae with high growth rates have been considered as promising organisms to replace fossil resources with contemporary primary production as a renewable source. However, their microscopic size makes it hard to be harvested for industrial applications. In this regard, multicellular macroalgae are more suitable for harvesting. Here, we show that Ulva meridionalis has the highest growth rate ever reported for a multicellular autotrophic plant. Contrasted to the known bloom-forming species U. prolifera growing at an approximately two-fold growth rate per day in optimum conditions, U. meridionalis grows at a daily rate of over fourfold. The high growth ability of this multicellular alga would provide the most effective method for CO2 fixation and biomass production.

DOI： 10.1038/s41598-020-69536-4

Language：Others   Publishing type：Research paper (scientific journal)  

Copyright © 2020 American Chemical Society. We studied the effects of surface morphology and carrier distribution of α-Fe2O3 electrodes on the enhancement of water electrolysis under microwave (MW) irradiation. We deposited α-Fe2O3 electrodes with various morphologies on Nb-doped rutile TiO2 (100) substrates. α-Fe2O3 films with rough and flat surfaces were deposited using electrodeposition (ED) and pulsed laser deposition (PLD), respectively. The ED α-Fe2O3 film showed a larger response to the MW electric field applied to the electrodes than did the PLD film. In addition, the response was linearly correlated with the MW electric field intensity. Using scanning MW microscopy, we found that the local MW susceptibility of the α-Fe2O3 electrode was enhanced at the grain boundary of the ED α-Fe2O3 film. Analysis of the surface band structure of both ED and PLD α-Fe2O3 films using electrochemical impedance spectroscopy showed that the ED α-Fe2O3 film had a wider depleted layer, indicating increased accumulation of holes on the surface of the electrode to enhance water oxidation. We concluded that the accumulation of holes at the grain boundary of the ED α-Fe2O3 film determines the enhancement of water oxidation under an MW electric field.

DOI： 10.1021/acs.jpcc.9b11179

Language：Others   Publishing type：Research paper (scientific journal)  

© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim The reduction of V2O5 to vanadium metal(0), that requires severe conditions in conventional reduction methods, was enabled to be proceeded in a short time of 1 h at 1273 K by the reaction with magnesium vapor with the isolation yield of V(0) in 55.6% by using microwave irradiation of 820 W. A pressurized pelletization of powdery V2O5 well-mixed with MgO powder at a specific mixing ratio followed by calcination in ambient air at 1173 K was crucial for the reaction since a complex oxide of MgV2O4, presumably as a precursor, was formed in calcination of the V2O5/MgO pellet to be reduced to V(0) by the reaction with magnesium. Calcination of V2O5/MgO pellets with different mixing ratios or different temperatures resulted in the formation of different kinds of complex oxide of vanadium and magnesium such as α-Mg2V2O7, Mg3(VO4)2, triclinic Mg2V2O7, and MgV2O6. While the yield of V(0) was dependent on the kind of the complex oxide, formation of MgV2O4 was essential as the precursor to the formation of V(0).

DOI： 10.1002/slct.201904547

Language：Others   Publishing type：Research paper (scientific journal)  

Copyright © 2020 American Chemical Society. Operando Raman spectroscopy was performed to understand the mechanism of a microwave (MW)-enhanced fixed-bed catalytic reaction. An MW operando Raman spectroscopy system was constructed by integrating a Raman spectroscopy probe (785 nm) with a single-mode (TM110) MW cavity resonator equipped with a semiconductor MW generator. MW heating enhanced the dehydration of 2-propanol to diisopropyl ether and propylene by +54 to +60% under the air flow condition. In the argon flow condition, the conversion of 2-propanol was further enhanced by +71 to +83% with >99.9% selectivity toward propylene when MW heating was used. Operando Raman spectroscopy revealed that MW irradiation enhances the reduction of the WO3 surface and exhibits intense light emission, especially under the argon flow condition. The enhanced generation of WO3-x species on the surface of the WO3 catalyst should be, therefore, a key factor in the enhancement of the dehydration of 2-propanol under MW irradiation.

DOI： 10.1021/acs.iecr.9b03876

Language：Others   Publishing type：Research paper (scientific journal)  

Copyright © 2020 American Chemical Society. Biodiesel was efficiently produced from biomass fatty acids using renewable gas H2 and a reusable heterogeneous catalyst under low-energy-consumption microwave conditions. As the decarboxylation of fatty acids to alkanes is an important transformation in the production of bio hydrofined diesel (BHD) and jet fuel, we herein report the development of a highly active and reusable Rh nanoparticle catalyst supported by a silicon nanowire array (SiNA-Rh) and its application in the decarboxylation of fatty acids to alkanes under mild conditions. More specifically, SiNA-Rh (500 mol ppm) selectively promoted the hydrogenative decarboxylation reaction at 200 °C under microwave irradiation (∼40 W) in a H2 atmosphere (10 bar) to afford the corresponding alkanes in high yields selectively. The only coproduct observed was carbon monoxide, an important and essential staple for the chemical industry. Importantly, carbon dioxide formation was not observed. Moreover, the aldehydes were efficiently converted to alkanes by SiNA-Rh, and this catalyst was reused 20 times without any loss in catalytic activity. Finally, to investigate the effects of microwave irradiation on the enhancement of this chemical transformation based on the Si nanorod structures present in the SiNA-Rh catalyst, the effect of the microwave electric field and magnetic field in the microwave to the reaction was experimentally investigated, and the spatial distribution of the electric field intensity around the surface of the Si nanostructure was simulated using the finite element method.

DOI： 10.1021/acscatal.9b04784

Language：Others   Publishing type：Research paper (scientific journal)  

© 2019 by the authors. Microwave (MW) heating of supported metal nanoparticles (NPs) presents attractive effects on catalysis such as the rapid heating processes and the enhancement of the reaction rate. Improving the heating property of the NPs, which act as the catalytic active sites, the MW effects will become more significant. Here we show a systematic study about the supported Pt NPs structure to improve the MW heating property. We found that the drastic heating was induced by a percolated Pt NPs structure, where the conduction electrons move around in the two-dimensional network. On the other hand, no heating was observed in an isolated Pt NPs system with the confined electrons. We conclude that the percolation of the Pt NPs giving the network structure is one of the important key factors for the efficient MW heating. The optimized Pt NPs catalyst leads to the dramatic MW effects on catalytic reactions.

DOI： 10.3390/pr8010072

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1039/c9cp06239d

Language：Others   Publishing type：Research paper (scientific journal)  

© 2019, The Author(s). The formation of local high temperature regions, or so-called “hot spots”, in heterogeneous reaction systems has been suggested as a critical factor in the enhancement of chemical reactions using microwave heating. In this paper, we report the generation of local high temperature regions between catalyst particles under microwave heating. First, we demonstrated that reaction rate of the dehydrogenation of 2-propanol over a magnetite catalyst was enhanced 17- (250 °C) to 38- (200 °C) fold when heated with microwave irradiation rather than an electrical furnace. Subsequently, the existence of microwave-generated specific local heating was demonstrated using a coupled simulation of the electromagnetic fields and heat transfer as well as in situ emission spectroscopy. Specific high-temperature regions were generated at the vicinal contact points of the catalyst particles due to the concentrated microwave electric field. We also directly observed local high temperature regions at the contact points of the particles during microwave heating of a model silicon carbide spherical material using in situ emission spectroscopy. We conclude that the generation of local heating at the contact points between the catalyst particles is a key factor for enhancing fixed-bed flow reactions under microwave irradiation.

DOI： 10.1038/s41598-018-35988-y

Language：English   Publishing type：Research paper (scientific journal)  

Microwave-assited solubilization of microalgae in high-temperature ethylene glycol

DOI： 10.1016/j.biombioe.2019.105360

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.heliyon.2019.e01887

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acs.jpclett.9b00629

Language：English  

In situ Raman monitoring of dielectric-heating-enhanced freeze-drying under different electromagnetic wave frequencies

Language：English   Publishing type：Research paper (scientific journal)  

Proton-Enhanced Dielectric Properties of Polyoxometalates in Water under Radio-Frequency Electromagnetic Waves

DOI： 10.3390/ma11071202

Language：Others  

Reversible Mechanochlomic Luminescence of a Heteroatom-Free Helically Chiral Hydrocarbon

Language：English   Publishing type：Research paper (scientific journal)  

Effect of Aspect Ratio on the Permittivity of GraphiteFiber in Microwave Heating

Language：English   Publishing type：Research paper (scientific journal)  

The current density of water reduction using a commercial Pt disk electrode was enhanced under 2.45 GHz microwave irradiation. The transitional alternation of temperature distribution was explained with a heat-transfer simulation using COMSOL Multiphysics based on the finite element method. Results show that most of the microwave energy was converted into thermal energy at the vicinity of the Pt electrode. A local high-temperature region enhancing the water-reduction reaction was hence formed.

DOI： 10.1246/cl.170686

Language：English   Publishing type：Research paper (scientific journal)  

Smelting of Scandium by Microwave Irradiation

Language：English   Publishing type：Research paper (scientific journal)  

Selective heating of microwave-absorbing solid catalysts in a heterogeneous medium may affect a chemical reaction; such selectivity cannot be achieved by conventional oil-bath or steam heating methods. Moreover, microwave methods are often misunderstood with respect to equipment and temperature measurements, so that additional experimentation is necessary. In this regard, the present study intended to clarify the effect of microwave selective heating on acid hydrolytic processes using a sulfonated activated carbon catalyst (AC-SO3H). The model reaction chosen was the acid hydrolysis of cellulose carried out in a Pyrex glass microwave reactor, with the process being monitored by examining the quantity of total sugar, reducing sugar, and glucose produced. Heat transfer from the catalyst to the aqueous solution through absorption of microwaves by the catalyst occurred as predicted from a simulation of heat transfer processes. The resulting experimental consequences are compared with those from the more uniform microwave conduction heating method by also performing the reaction in a SiC microwave reactor wherein microwaves are absorbed by SiC. Some inferences of the influence of microwave selective heating of carbon-based catalyst particles are reported. Under selective heating conditions (Pyrex glass reactor), the yield of glucose from the acid hydrolysis of cellulose was 56% upon microwave heating at 200 degrees C, nearly identical with the yield (55%) when the hydrolytic process was performed under mainly conventional heating conditions in the SiC reactor. Although the beneficial effect of catalyst selective heating was not reflected in the reaction efficiency, there were substantial changes in the state of adsorption of cellulose on the catalyst surface.

DOI： 10.3390/catal7080231

Language：English   Publishing type：Research paper (scientific journal)  

Green macroalgae, such as Ulva spp., has a higher growth rate than terrestrial lingocellulosic biomass, which often leads to serious environmental issues such as green tide. So, it is a promising feedstock for biorefineries. Hiraoka produced Ulva with reproducible compositions and sizes by our original cultivation method. The macroalgae contained approximately 35 wt% of a soluble polysaccharide called ulvan, which is a sulfated glucuronorhamnan polysaccharide. The catalytic conversion of extracted ulvan was performed under hydrothermal conditions at 130 degrees C by using solid acid catalysts. The Amberlyst 70 catalyst has a stable structure and gave monosaccharides in quantitative yield, predominantly in the form of rhamnose. The Amberlyst 70 catalyst showed higher activity than sulfonated activated- carbon (AC-SO3H) in the hydrothermal conversion of ulvan, although Amberlyst 70 showed lower catalytic activity than AC-SO3H in the hydrolysis of starch.

DOI： 10.1002/cctc.201700100

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.4172/2165-784X.1000279

Language：English   Publishing type：Research paper (scientific journal)  

Electromagnetic and heat-transfer simulations were used to study the effects of microwave-generated nonuniform temperature distributions in a catalyst bed on the rate enhancement of a fixed-bed flow reaction. We used the dehydrogenation of ethylbenzene over a magnetite catalyst as a model reaction. During the microwave reaction, a temperature gradient was generated in the catalyst bed; the highest temperature occurred at the core of the catalyst bed, and it parabolically decreased toward the surface. Using these simulation results and Arrhenius parameters, the reaction rates were estimated by considering the nonuniform temperature distribution. The measured reaction rate was 36% larger than the simulated value, indicating that the rate enhancement under microwaves can, not only be attributed to the nonuniform temperature distribution in the catalyst bed. This could be due to nonequilibrium local heating (the so-called hot spot) in the very small region around the catalyst particle.

DOI： 10.1021/acs.iecr.7601413

Language：English   Publishing type：Research paper (scientific journal)  

Crystalline orientation control using self-assembled TiO2 nanosheet scaffold to improve CH3NH3PbI3 perovskite solar cells

Language：English   Publishing type：Research paper (scientific journal)  

As next-generation printable solar cells, perovskite solar cell utilizing organometal halide perovskite crystalline semiconductor as the active layer has been considered as one of the most promising systems for its high efficiency (> similar to 22%) and construction with low-cost materials. Annealing process of organometal halide perovskite crystalline films are, however, relatively time-consuming process for the perovskite solar cells. We propose the microwave heating applied to the annealing process of the CH3NH3PbI3 perovskite crystalline films for converting the intermediate state of as-coated precursor films into perovskite poly-crystalline films. Observed rapid conversion process into perovskite crystals with higher crystallinity and even the degradation of perovskite to be PbI2 by evaporation of methylammonium iodide at relatively lower temperature to the conventional hotplate heating imply a promising potential to achieve novel high throughput annealing process with high-quality crystallinity of perovskite films at low-temperature due to direct and effective heating of CH3NH3PbI3 films by the microwave irradiation. (C) The Electrochemical Society of Japan, All rights reserved.

DOI： 10.5796/electrochemistry.85.236

Language：English   Publishing type：Research paper (scientific journal)  

Magnesium (Mg) is a lightweight metal with applications in transportation and sustainable battery technologies, but its current production through ore reduction using the conventional Pidgeon process emits large amounts of CO2 and particulate matter (PM2.5). In this work, a novel Pidgeon process driven by microwaves has been developed to produce Mg metal with less energy consumption and no direct CO2 emission. An antenna structure consisting of dolomite as the Mg source and a ferrosilicon antenna as the reducing material was used to confine microwave energy emitted from a magnetron installed in a microwave oven to produce a practical amount of pure Mg metal. This microwave Pidgeon process with an antenna configuration made it possible to produce Mg with an energy consumption of 58.6 GJ/t, corresponding to a 68.6% reduction when compared to the conventional method.

DOI： 10.1038/srep46512

Language：English   Publishing type：Research paper (scientific journal)  

Microwave-assisted hydrothermal extraction was applied for production of sulfated polysaccharides from Ulva spp. and Monostroma latissimum. The maximum ulvan yields attained 40.4 +/- 3.2% (Ulva meridionalis) and 36.5 +/- 3.1% (Ulva ohnoi) within 4 min of come-up time and 10 min of extraction time at 160 degrees C, respectively. The rhamnan sulfate yield from M. latissimum further attained 53.1 +/- 7.2% at 140 degrees C. The sulfated polysaccharides were easily recovered from the extract by simple ethanol precipitation. In addition, molecular weights and viscosity of the extracted polysaccharides could be controlled by varying the extraction temperature. Dielectric measurement revealed that ionic conduction was the important parameter that affect the microwave susceptibility of algae-water mixture. The sulfated polysaccharides extracts are expected as potential feedstock for medical and food applications. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.foodchem.2016.04.121

Language：English   Publishing type：Research paper (scientific journal)  

Enhancement of anodic current attributed to oxygen evolution on alpha-Fe2O3 electrode by microwave oscillating electric field
Various microwave effects on chemical reactions have been observed, reported and compared to those carried out under conventional heating. These effects are classified into thermal effects, which arise from the temperature rise caused by microwaves, and non-thermal effects, which are attributed to interactions between substances and the oscillating electromagnetic fields of microwaves. However, there have been no direct or intrinsic demonstrations of the non-thermal effects based on physical insights. Here we demonstrate the microwave enhancement of oxidation current of water to generate dioxygen with using an alpha-Fe2O3 electrode induced by pulsed microwave irradiation under constantly applied potential. The rectangular waves of current density under pulsed microwave irradiation were observed, in other words the oxidation current of water was increased instantaneously at the moment of the introduction of microwaves, and stayed stably at the plateau under continuous microwave irradiation. The microwave enhancement was observed only for the alpha-Fe2O3 electrode with the specific surface electronic structure evaluated by electrochemical impedance spectroscopy. This discovery provides a firm evidence of the microwave special non-thermal effect on the electron transfer reactions caused by interaction of oscillating microwaves and irradiated samples.

DOI： 10.1038/srep35554

Language：English   Publishing type：Research paper (scientific journal)  

We demonstrate the electron transfer from the conduction band of tantalate nanosheets to that of tungstate nanosheets depending on the interlayer distance in the alternate-stacked structure prepared by the thiol-ene click reaction of thiol-grafted tantalate nanosheets and alkene-grafted tungstate nanosheets. The interlayer distance is precisely controlled from 0.93 to 1.64 nm by changing the methylene chain number of the organic bridges. The logarithm of the rate constant of the electron transfer decreases linearly with the distance.

DOI： 10.1246/cl.160526

Language：English   Publishing type：Research paper (scientific journal)  

We demonstrate two novel methods for the measurement of the temperatures of reaction spaces locally heated by microwaves, which have been applied here to two example systems, i.e., BaTiO3 particles covered with a SiO2 shell (BaTiO3-SiO2) and layered tungstate particles. Photoluminescent (PL) probes showing the temperature-sensitivity in their PL lifetimes are located in the nanospaces of the above systems. In the case of BaTiO3-SiO2 core-shell particles, rhodamine B is loaded into the mesopores of the SiO2 shell covering the BaTiO3 core, which generates the heat through the dielectric loss of microwaves. The inner nanospace temperature of the SiO2 shell is determined to be 28 degrees C higher than the bulk temperature under microwave irradiation at 24 W. On the other hand, Eu3+ is immobilized in the interlayer space of layered tungstate as the PL probe, showing that the nanospace temperature of the interlayer is only 4 degrees C higher than the bulk temperature. This method for temperature-measurement is powerful for controlling microwave heating and elucidates the ambiguous mechanisms of microwave special effects often observed in chemical reactions, contributing greatly to the practical application of microwaves in chemistry and materials sciences.

DOI： 10.1039/c6cp02034h

Language：English   Publishing type：Research paper (scientific journal)  

This study investigated the effects of ionic conduction of electrolytes under microwave field to facilitate hydrothermal hydrolysis of corn starch and crystalline cellulose (Avicel), typical model biomass substrates. Addition of 0.1 M NaCl was effective to improve reducing sugar yield by 1.61-fold at unit energy (kJ) level. Although Avicel cellulose was highly recalcitrant to hydrothermal hydrolysis, addition of 0.1 M MgCl2 improved reducing sugar yield by 6.94-fold at unit energy (kJ). Dielectric measurement of the mixture of corn starch/water/electrolyte revealed that ionic conduction of electrolytes were strongly involved in facilitating hydrothermal hydrolysis of polysaccharides. (C) 2015 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carbpol.2015.11.022

Language：Others   Publishing type：Research paper (scientific journal)  

© 2014 Elsevier Ltd. All rights reserved. This study investigated the dielectric properties of sodium alginates and carrageenans in water at frequencies between 100 MHz and 20 GHz in regard to water-hydrocolloid interactions via acidic functional groups. Both sodium alginates and carrageenans showed conduction loss at lower frequencies and dielectric loss at higher frequencies. Reduction and desulfation of sodium alginates and carrageenans, which decreased the numbers of acidic functional groups, decreased their conduction loss. In addition, H+-form carrageenans showed the highest ionic conduction. Correlational analysis of dielectric properties and related physical parameters showed that the loss tangent (tanδ) of the hydrocolloid solution was determined by the conductivity of the aqueous solution. Especially at pH below 2, strong H+conduction was associated with high tanδ probably due to the Grotthuss mechanism. The molecular dynamics of free water and H+, viscosity conditions were also suggested to be associated with dielectric property of water-hydrocolloid system.

DOI： 10.1016/j.carbpol.2014.08.092

Language：Others   Publishing type：Research paper (scientific journal)  

Dielectric properties of aqueous solutions of sulfated hydrocolloids (ulvan and rhamnan sulfate) extracted from green macroalgal biomass were studied in a frequency range of 100 MHz-10 GHz. Counterion exchange of native hydrocolloids (mixture of Na+, Mg2+ and Ca2+) to H +-form showed significant increase in loss factor due to ionic conduction. On the other hand, desulfations decreased their loss factors. The results suggested that ionic conduction of H+ has significant contribution to loss factors. Additionally, H+-form hydrocolloids showed significant improvement in hydration, which might also affect the dielectric property of the solution by reducing the amount of free water. The viscosity, however, did not show apparent relevance with the dielectric property. © 2014 Elsevier Ltd.

DOI： 10.1016/j.carbpol.2014.03.002

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.5614/j.math.fund.sci.2014.46.2.2

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1039/C3GC42027B

Language：English   Publishing type：Research paper (scientific journal)  

The mechanical defensive performance of fruit cuticular membranes (CMs) is largely dependent on the molecular arrangement of their constituents. Here, we elucidated nano-sized interactions between cutin and triterpenoids in the cuticular matrix of Fuyu persimmon fruits (Diospyros kaki Thunb. cv. Fuyu), focusing on the mechanical properties using a combination of polymer analyses. The fruit CMs of Fuyu were primarily composed of wax (34.7%), which was predominantly triterpenoids followed by higher aliphatic compounds, and cutin (48.4%), primarily consisting of 9,10-epoxy-18-hydroxyoctadecanoic acid and 9,10,18-trihydroxyoctadecanoic acid. Based on the tensile tests of the CM, the removal of wax lead to a considerable decrease in the maximum stress and elastic modulus accompanied by an increase in the maximum strain, indicating that wax is of significant importance for maintaining the mechanical strength of the CM. Wide-angle X-ray diffraction and relaxation time measurements using solid-state C-13 nuclear magnetic resonance indicated that the triterpenoids in the cuticular matrix construct a nanocomposite at a mixing scale below 20-24 nm; however, the higher aliphatic compounds did not exhibit clear interactions with cutin. The results indicated that the triterpenoids in the cuticular matrix endow toughness to the CM by functioning as a nanofiller.

DOI： 10.1371/journal.pone.0075275

Language：English   Publishing type：Research paper (scientific journal)  

Polyoxometalate (POM) clusters were utilized as recyclable acid catalysts and microwave-absorbing agents for the microwave-assisted hydrolysis of corn starch and crystalline cellulose. Phosphotungstic (PW) and silicotungstic (SiW) acids showed high hydrolyzing activity, while phosphomolybdic acid (PMo) showed lower glucose stability. The PW catalyst could be recycled by ether extraction at least 4 times without changing its catalytic activity. The addition of PW could reduce the energy demand required for running the hydrolysis by 17-23%. The dielectric property of the aqueous PW solution was important for increasing the microwave-absorption capability of the reaction system and reducing the energy consumption. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.biortech.2013.06.092

Language：English   Publishing type：Research paper (scientific journal)  

The stabilities of five neutral monosaccharides (glucose, galactose, mannose, arabinose, and xylose) were kinetically compared after the molecules were submitted to microwave heating (internal heating) and induction heating (external heating) under completely identical thermal histories by employing PID (proportional, integral, and derivative) temperature controlled ovens and homogeneous mixing. By heating in water at 200 degrees C, the rate constants for the decomposition reactions varied from 2.13 x 10 (4) to 3.87 x 10 (4) s (1) for microwave heating; however, the values increased by 1.1-to 1.5-fold for induction heating. Similarly, in a dilute (0.8%) sulfuric acid solution, the decomposition rate constants varied from 0.61 x 10 (3) to 2.00 x 10 (3) s (1) for microwave heating; however, the values increased by 1.5-to 2.2-fold for induction heating. The results show that microwave heating imparts greater stability to neutral monosaccharides than does induction heating. The undesirable decomposition of monosaccharides at the surface boundary of reactor walls may have increased the probability of monosaccharide decomposition during induction heating. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carres.2013.04.013

Language：English   Publishing type：Research paper (scientific journal)  

Chemical constituents of cuticular membranes (CMs) isolated from three tea cultivars (Camellia sinensis (L) O. Kuntze cvs. Yabukita, Samidori and Gokou) were compared. All CMs from the adaxial side of the leaves showed higher accumulation of wax, cutin and polysaccharide, while those from the abaxial side were abundant in cutan, showing the adaptation of the adaxial side to abiotic stresses, such as wind and rain, in contrast to the abaxial side, which provides defence against pathogens. Yabukita, a major tea cultivar in Japan, developed thick CMs while Samidori and Gokou, shade-cultivated tea cultivars, had lighter CMs, reflecting their thin and soft leaves. CMs rapidly accumulated 9,10-epoxy-18-hydroxyoctadecanoic acid at a very early stage of leaf development. Additionally, shade treatment did not influence cutin biosynthesis in CMs, reflecting high adaptation of tea leaves under low light levels. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.foodchem.2012.10.116

Language：English   Publishing type：Research paper (scientific journal)  

Total refinery of constituents of green tea residue was achieved by combination of microwave-assisted alkaline pretreatment and enzymatic hydrolysis. Alkaline pretreatment was effective at separating pectic polysaccharides, protein, phenolic compounds and aliphatic compounds (probably originating from cuticular components), and the solubilization rate was attained 64-74% by heating at 120-200 degrees C. The higher heating value (HHV) of alkali-soluble fraction attained 20.1 MJ/kg, indicating its usability as black-liquor-like biofuel. Successive cellulolytic enzymatic hydrolysis mainly converted cellulose into glucose and attained the maximum solubilization rate of 89%. Final residue was predominantly composed of aliphatic cuticular components with high proportion in 9,10,18-trihydroxyoctadecanoic acid (30.1-48.6%). These cuticular components are potential alternative feedstock for aliphatic compounds commonly found in oil plants. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.biortech.2013.01.001

Language：English   Publishing type：Research paper (scientific journal)  

Microwave irradiation was compared with induction heating for hydrothermal hydrolysis of cellobiose. Microwave heating improved glucose selectivity and resulted in a pH of the hydrolyzates that was <= 0.57 units lower than those from conventional heating, which suggests that fewer side-reactions occurred. Halide salts of alkali and alkali earth metals improved microwave-assisted hydrothermal saccharification of cellobiose at lower reaction severity by around 0.3 of logR(0). NaCl addition of >= 10 mM reduced the required microwave output to 58.6-66.2% as compared to conventional microwave-hydro-thermal hydrolysis without halide salts. Kinetic analyses revealed that the addition of salt increased the hydrolysis rate by increasing the frequency factor of the reaction. The results showed that microwave irradiation in the presence of microwave-absorbing salts is effective for hydrothermal hydrolysis of carbohydrates. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.biortech.2012.07.086

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.proche.2012.06.003

Language：English   Publishing type：Research paper (scientific journal)  

Chemical and mechanical properties of the leaf cuticular membranes (CMs) of a mangrove, Sonneratia alba J. Smith, were analysed at various leaf development stages to evaluate their tolerance to environmental stress. Our analyses demonstrate that the CMs from leaves of S. alba at different growth stages are generally rich in wax (21.525.7%) and cutin (52.463.4%) which rapidly accumulate at the early stages of leaf growth, while cutan (4.310.3%) and polysaccharide (2.37.7%) continuously accumulate throughout growth. Immature CMs are physically weak and highly viscoelastic. However, CMs become strengthened and stiffened during leaf expansion and maturation (by factors of about 1.5 and 2.4, respectively) while their flexibility decreases (6883% decrease). Finally, the CMs lose their strength at the senescent stage (3043% decreasement). Correlation analysis between chemical composition and mechanical properties revealed that the cutin matrix is mainly responsible for the high viscoelastic properties of CMs, while wax, cutan and polysaccharide contributed to their elasticity. Wax also affected the strength of the CMs, whereas cutan and polysaccharide showed rigidizing effect. Rapid accumulation of wax and cutin in the CMs after bud burst followed by the mechanical supports of cutan and polysaccharide in an isolateral manner contributed to the remarkable environmental tolerance of S. alba.

DOI： 10.1111/j.1365-3040.2012.02482.x

Language：English   Publishing type：Research paper (scientific journal)  

Fruit cuticular membranes (CMs) were isolated from 27 cultivars of Diospyros kaki Thunb., and relationships among their chemical compositions, densities and mechanical properties were analysed. Wide cultivar dependency was observed in both chemical compositions and mechanical properties, however, astringency did not show clear correlation with them. Densities of the CMs showed significant positive correlation with maximum stress and elastic modulus, but negative correlation with maximum strain. Positive correlations were also observed in elastic modulus-polysaccharide content and maximum strain-polysaccharide content, and negative correlation in elastic modulus-cutin content on a weight over unit area (mu g/cm(2)) basis. The integration of densities of fruit CMs and their chemical constituents may explain the mechanical properties which are specific to each cultivar of D. kaki fruit. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.foodchem.2011.12.039

Language：English   Publishing type：Research paper (scientific journal)  

The superior effects of addition of activated carbon were evidenced for microwave assisted hydrolysis of starches in cassava pulp and tapioca flour under hydrothermal conditions varying irradiation temperature (160-230 degrees C at 5 min), duration of heating time (5-18 min at 210 degrees C) and amount of activated carbon at 0.5-2.0:1:20 of activated carbon:solid:liquid ratio. The presence of 1.0 g/g in microwave-assisted hydrolysis gave much improved glucose yields (44.49% for cassava pulp and 71.93% for tapioca flour) at lower heating temperature (220 degrees C and 200 degrees C, each for 5 min) with suppressed formation of secondary decomposed compounds than those without addition of activated carbon (32.41% in cassava pulp at 230 degrees C and 55.11% in tapioca flour at 240 degrees C, each for 5 min). The highest glucose yield from cassava pulp (52.27%) was obtained after heating at 210 degrees C for 15 min. (C) 2011 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.carbpol.2011.08.033

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.51850/wrj.2011.2.1.69-72

Language：English   Publishing type：Research paper (scientific journal)  

Activated carbons were investigated for their heat catalytic effects to improve saccharification of starch by autohydrolysis in water under microwave electromagnetic field, and the results were compared with graphite and carbon nanotubes. The activated carbons with low adsorptive capacity of maltose showed high saccharification rate, while those with high adsorptive capacity exhibited low saccharification. In addition, the former activated carbons decreased the saccharification temperature by 10-30 degrees C. Maltooligosaccharides produced in the presence of the latter activated carbons were recovered by desorption with 50% aqueous ethanol. The results indicated that both adsorptive capacities of maltooligosaccharides and catalytic effects of hot spots arisen from the uneven surface structure of activated carbons might contribute to the improvement in starch saccharification. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.biortech.2010.12.013

Language：English   Publishing type：Research paper (scientific journal)  

Phenolic compounds were extracted from three kinds of tea residues (green, oolong and black tea residues) by microwave-assisted extraction in water under autohydrolytic conditions without using any catalyst or organic solvent. Productions of phenolic compounds were enhanced by microwave heating at 230 C. The main phenolic constituent in the extract from green tea residue was pyrogallol (24.6%) which was estimated to be originated from degradations of catechins. Derivatives of guaiacyl units of lignin such as dihydroconiferyl alcohol (10.3%) and vanillin (8.1%) were, however, the main constituents in oolong tea residue. In the case of black tea residue, derivatives of both catechins and lignin were comparably extracted. These phenolic compounds are interesting as a bio-based chemical feedstock such as phenolic precursors and antioxidants. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.foodchem.2010.05.088

Language：English   Publishing type：Research paper (scientific journal)  

Simultaneous extraction by microwave-irradiation and crystallisation were performed in the same pot of solvent of 70% (v/v) aqueous ethanol for isolation of hesperidin from thinned immature fruit peels of Citrus unshiu as refining of Citrus waste biomass. The hesperidin content in immature fruits peels was about 3.2-fold higher than that of mature fruit. After microwave-assisted extraction (MAE), the yield of hesperidin reached 58.6 mg/g, which was comparable to the amount obtained after extraction using DMSO:methanol (1:1, v/v) as a solvent for 30 min at room temperature. Heating temperature and time for isolation of hesperidin crystallites were optimised as 140 degrees C and 8 min by using response surface methodology. Under this optimal condition, 86.8% (47.7 mg/g) of total hesperidin was isolable by MAE and low-temperature storage (5 degrees C, 24 h). (c) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.foodchem.2010.04.051

Language：English   Publishing type：Research paper (scientific journal)  

Microwave-assisted extraction (MAE) was applied for production of carbohydrates mainly consisting of arabinoxylan from corn pericarp which is an industrial waste of corn starch production by using hot compressed water as a solvent. The solubilization rate increased with increase in heating temperature and reached 75.2% at 220 degrees C. The main extracted materials were carbohydrates consist of glucose, xylose and arabinose indicating solubilization of starch and hemicellulose, while residues were composed of cellulose. Four independent variables (heating temperature, come-up time, heating time and solid to liquid ratio) were optimized for maximizing the carbohydrates yield using the response surface methodology including fractional factorial design, the path of steepest ascent and central composite design. The optimized condition was as follows; heating temperature 176.5 degrees C, come-up time 2 min, heating time 16 min and solid to liquid ratio 1/20 (g/mL), respectively. The maximal yield attained 70.8% of carbohydrates with predominant production of xylo-oligosaccharides. (C) 2010 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.biortech.2010.05.011

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.51850/wrj.2010.1.1.56-63

Language：English   Publishing type：Research paper (scientific journal)  

Stone of Prunus mume (P. mume) is a by-product of pickled P. mume industry. Stones of native and pickled P. mume, mainly composed of holocellulose (83.8 +/- 1.8% and 65.1 +/- 0.3%, respectively) and acid-insoluble lignin (25.3 +/- 2.2% and 30.6 +/- 0.9%, respectively), were autohydrolyzed by microwave heating to extract polysaccharides and phenolic compounds. By heating at 200 to 230 degrees C, 48.0% to 60.8% of polysaccharide and 84.1% to 97.9% of phenolic compound were extracted in water along with partial degradation of hemicelluloses and lignin. The extracted liquors showed antioxidant activity against hydroxyl radical and DPPH radical originated from phenolic compounds. The pickled P. mume stone showed higher autohydrolyzability and microwave absorption capacity than the native stone due to absorbed salts and acids during pickling in fruit juice of P. mume with external addition of sodium chloride. Pickling process in salty and weak acidic juice seemed to be a kind of pretreatment for softening the stones prior to autohydrolysis induced by microwave heating.

DOI： 10.1111/j.1750-3841.2009.01466.x

Language：English   Publishing type：Research paper (scientific journal)  

Okara, a soybean by-product of tofu production, was treated with microwave irradiation in water for solubilization of its components. The solubilization rate increased with increasing temperature and reached higher than 70% around 200 degrees C with a heating time of 7 min. The main solubilized components were neutral carbohydrates consisting of arabinose and galactose, while the residues were mainly composed of cellulose. LV-SEM images confirmed solubilization of cell wall components. Production of new polyphenolic compounds that have antioxidant activity was observed above 180 degrees C. The heating temperature and heating time were optimized for neutral carbohydrate solubilization using the response surface methodology. The optimized condition was heating at 196 degrees C for 2 min, indicating that a short heating time is effective for solubilization of carbohydrates to prevent secondary decomposition.

DOI： 10.3136/fstr.15.307

Language：English   Publishing type：Research paper (scientific journal)  

Microwave heating was used to produce aqueous-soluble components from green, oolong, and black tea residues. Heating at 200-230 degrees C for 2 min extracted 40-50% of polysaccharides and 60-70% of the polyphenols. Solubilization of arabinose and galactose by autohydrolysis occurred with heating above 170 degrees C, whereas heating above 200 degrees C was necessary to solubilize xylose. Catechins were soluble in water by heating at low temperature (110 degrees C); however, new polyphenols having strong antioxidant activity were produced above 200 degrees C. The amount of solubilized materials and antioxidant activity increased with increased fermentation of harvested tea leaves (green tea < oolong tea < black tea). Cutin, a plant biopolyester, remained in the residue after heating as did cellulose and lignin/tannin. The predominant cutin monomer that was recovered was 9,10-epoxy-18-hydroxyoctadecanoic acid, followed by dihydroxyhexadecanoic acid and 9,10,18-trihydroxyoctadecanoic acid.

DOI： 10.1021/jf802253s

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1039/c6ra28778f

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.proche.2012.06.040

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.2216/16-109.1

Responsible for pages：In Fuels, Chemicals and Materials from the Oceans and Aquatic Sources   Language：English   Book type：Scholarly book

DOI： 10.1002/9781119117193.ch2

Responsible for pages：In Hydrothermal processing in biorefineries – Production of bioethanol and high added- value compounds of second and third generation biomass   Language：English   Book type：Scholarly book

DOI： 10.1007/978-3-319-56457-9_19

Responsible for pages：Production of bioethanol and high added- value compounds of second and third generation biomass   Language：English   Book type：Scholarly book

DOI： 10.1007/978-3-319-56457-9_19

Responsible for pages：In Chemical Reactions on the Interfaces of solids under microwaves   Language：English   Book type：Scholarly book

DOI： 10.1515/9783110479935-007

Responsible for pages：pp. 103-126   Language：English   Book type：General book, introductory book for general audience

DOI： 10.1016/B978-0-12-802323-5.00005-0

Responsible for pages：In Microwaves in Catalysis: Methodology and Applications, pp. 303-321,   Language：English   Book type：Scholarly book

DOI： 10.1002/9783527688111.ch15

Responsible for pages：pp. 717-720, 721-725   Language：Japanese   Book type：Scholarly book

Responsible for pages：pp.697-722   Language：English   Book type：Scholarly book

DOI： 10.5772/14040

Responsible for pages：In Research Advances in Agricultural and Food Chemistry   Language：English   Book type：Scholarly book

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Event date： 2021.3 - 2022.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2021.1

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

DOI： http://ci.nii.ac.jp/ncid/AN00037573

J-GLOBAL

researchmap

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

DOI： 61巻,4号,pp. 215-221

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：English   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Language：Japanese   Publishing type：Article, review, commentary, editorial, etc. (scientific journal)  

Type：Peer review 

Number of peer-reviewed articles in foreign language journals：26

Number of peer-reviewed articles in Japanese journals：0

Proceedings of International Conference Number of peer-reviewed papers：5

Proceedings of domestic conference Number of peer-reviewed papers：0

Type：Competition, symposium, etc.