A combined system of laboratory X-ray CTR scattering measurement and MOVPE growth facility was set up and CTR measurement on GaN/GaInN/GaN heterostructure was conducted at room temperature and high temperatures up to 1000 ℃. Clear CTR signals and composition profiles were obtained even at 1000 ℃.
A new X-ray CTR scattering measurement system was reported that was equipped with a Johansson monocromator to focus X-rays at a sample position. Using the focused X-rays and a two-dimensional detector, X-ray CTR scattering measurement was able to be carried out without moving any component of the measurement system. The results of the X-ray CTR scattering measurement using the new system successfully demonstrated that the CTR scattering profiles were comparable to that measured at PF using synchrotron radiation even when the measurement time was 10 minutes or longer. The results suggested that the new measurement system is useful for quick and in-situ X-ray CTR scattering measurements.
The distributions of As atoms at InP/GaInAs interfaces were investigated by analyzing the X-ray CTR scattering spectra for the samples grown at different growth temperatures and with different H2-flushing times. From the results of the investigation, the adsorption and desorption processes of As atom on the GaInAs surface during the growth were discussed. Although the desorption of As from a surface progressed at all the investigated temperatures, 590, 620, and 650℃, a part of the As atoms, about 1.2[ML], remained on the surface even when the H2-flushing time was long. On the other hand, when the H2-flushing time was short, the amounts of As atoms were larger at higher growth temperatures, which suggested the decomposition of As precursor was enhanced at higher growth temperatures. All the results strongly indicated that the amount of As atoms incorporated in InP layer sensitively depends on the balance between the desorption and adsorption of As and that it is difficult to predict the degree of distribution of the As without a high resolution interface analysis like the X-ray CTR scattering measurement.
We show a quantitative analysis of the strain field beneath the Si3N4/Si(001) interface formed by nitrogen-hydrogen (NH) radicals (the Xe/NH3 plasma nitridation). The strain field was investigated by using a multiple-wave X-ray diffraction phenomenon, i.e., interaction between the Bragg reflection and crystal-truncation-rod (CTR) scattering. We present a master formula for the amplitude of CTR scattering from a crystal with strain. We constructed model functions for the strain field and determined several parameters using the least-squares fitting. The result suggests that inversion of the sign of the strain occurs near the interface.
An x-ray optics was proposed for dynamical diffraction measurements of a non-ideal crystal. It was composed of a pair of channel-cut Si (004) crystals and a one-dimensional focusing lens system. Vertical angular divergence values were measured as FWHM's of ca. 1.3 arc secs for an incident photon energy of 12.4 keV during a rocking scan around the analyzer sapphire 0006 reflection when the second channel-cut crystal was fixed at five deviation angles. The experimental angular resolution deconvoluted is about 1.3 arc secs at the deviation angle of ca. 0.7 arc sec. A typical photon flux was around 109 photons /s as a peak value of the rocking scan for an incident slit of 0.2 x 0.1mm. The horizontal beam size measured at the focal distance of ca. 200 mm was 4.3 μm.
The authors proposed that novel oxide superlattice structures of crystalline TiO2/ZnO on sapphire substrates could be fabricated for high-reflection multilayer mirrors at 2.734 nm. In the experimental study, both rutile TiO2 (200) and wurtzite ZnO (0001) thin films were grown epitaxially on the same sapphire (0001) substrates by atomic layer epitaxy (ALE) at 450℃. the authors also demonstrated for the first time that the novel oxide superlattice structure of 10-bilayer TiO2/ZnO on a sapphire substrate gave high reflectance at 2.734 nm.
A novel attosecond multilayer mirror was designed at “water-window” wavelengths with a combination of TiO and NiO, which were the same NaCl-type crystal structures of nearly equal lattice constants (TiO = 0.41766 nm, NiO = 0.41684 nm). The theoretical calculation of the TiO/NiO multilayer mirror indicated that the high reflectivity over 50% was attainable at 2.73 nm and at an incident angle of 18.9° from the normal incidence. Moreover, it also indicated that stacking of some multilayer blocks with different periods became effective in reflecting attosecond soft x rays.
High-resolution Rutherford backscattering spectrometry (HR-RBS) and X-ray reflectivity (XRR) are both powerful tools that can be used to investigate thin film structures with the same depth resolution. HR-RBS can be used to analyze low-density contrast films since it reveals the chemical composition in films. The elemental information aids the XRR analysis of films containing localized hydrogen atoms and low-electron-density contrast layers.
An oxidation state of a small amount of Ti in the naturally formed passivation film on stainless steel (Fe-Cr alloy, SUS321) was non-destructively evaluated using angle resolved hard X-ray photoelectron spectroscopy (HX-PES) at BL46XU in SPring-8. The synchrotron radiation with photon energy of 7942.5 eV was used as an excitation source. The intensity of Cr 1s peak assigned to metallic state gradually increased with increasing of take-off angle θ from 15° to 30°. It drastically increased at larger take-off angle region (30~80°). The results clearly suggest a formation of passivation film on SUS321 and enough large probing depth of HX-PES to evaluate the chemical states of elements placed below the passivation film. Ti 1s spectra collected at take-off angles from 15 to 80° revealed only Ti in tetravalent state. Taking an inelastic mean free path length of Ti 1s photoelectrons into account, it suggests that only Ti in tetravalent state exists in and below the passivation film.
High intensity Cu Kα X-ray was generated in helium at atmospheric pressure (760 torr) using a commercial millijoule high-repetition rate Ti: sapphire laser. The characteristic Kα X-ray was generated by focusing the 0.06 mJ－1.46 mJ, 100 fs and 1 kHz repetition femtosecond laser onto a solid Cu target to a spot with a 5 μm diameter. We obtained the characteristic Kα X-ray of 5.4 × 109 photos/s into 2π sr at a 1 kHz repetition rate with 5.0 × 10-6 conversion efficiency. Kα X-ray intensity can be enhanced with 4－8% prepulse plasma into 7.7 × 109 photos/s/sr with 6.8 × 10-6 conversion efficiency. The X-ray intensity and conversion efficiency in helium achieved the almost the same level as in vacuum. Such vacuum-free femtosecond X-ray source with a tabletop laser can be a promising and easy accessible tool for time-resolved X-ray diffraction and other radiographic applications. The time-resolved X-ray diffraction experiment would reveal the ultrafast dynamics in crystalline materials, such as coherent phonon vibrations and ultrafast phase transitions.
X-ray reflectivity of a Pd-based amorphous alloy thin film was measured by an energy dispersive method in the vicinity of crystallization temperature upon heating. A large number of oscillations of X-ray reflectivity were clearly observed, because the surface of the amorphous alloy thin film is extraordinary smooth. The oscillations of X-ray reflection became smaller after crystallization of the film, as the surface roughness of the film is increased by grain boundaries. Thickness of the film estimated from the distance between the peaks of the oscillations was decreased when the film was heated to higher temperature than 140 ℃. It is considered that the crystallization temperature of the Pd-based amorphous alloy thin film is about 140 ℃.
X-ray specular and off-specular reflection was investigated to analyze the out-of-plane and in-plane structures of a globular protein adsorbed at an air/water interface in the presence of a salt. The x-ray reflectivity was used to obtain the electron density profile normal to the surface. The electron density profile indicates the presence of a double layer consisting of a lower-density lysozyme layer below a densely packed top layer. From the off-specular diffuse scattering, the protein layer could be well described by a simple exponentially decaying height-height correlation function with a correlation length of 500 Å. This suggests that the protein molecules aggregate and form islands on the water surface. A simple formula for describing the off-specular excess scattering above the capillary wave fluctuation was proposed to explain the lateral fluctuation of an inhomogeneous layer above a liquid surface.
Changes in the layer thickness and roughness of as-prepared methylcellulose (MC) films with thermal cycling were studied using the X-ray reflectivity technique. It was found that thermal stress induced by rapid and slow thermal cycling brings no apparent changes in the surface and interface roughness after thermal cycling. On the other hand, some reduction of layer thickness was observed. With rapid thermal cycling, the relative shrinkage of the films is much higher at a maximum of 5% change at 15 cycles. With slow thermal cycling, it remains at a maximum of 3.6% even after 20 thermal cycles. Such film shrinkage is highly dependent on the initial film thickness and the amount of absorbed water molecules in the film.
The present paper reports on brittle spall fracture of aluminum foil and sheet at room temperature. It was found that fairly rapid fracture takes place upon contact with liquid Ga83In17 alloy in the presence of moisture. A rapid increase in temperature was observed during the reaction. Observation in a different atmosphere clarified that moisture has a strong influence on the present fracture process, although the phenomena are basically correlated to embrittlement by liquid Ga83In17 alloy penetrating into the grain boundaries of aluminum polycrystals. The fine debris obtained through the spall fracture was identified as metallic aluminum, neither bulk oxides nor hydroxides.
Recently, the contamination of electromagnetic environment has become more serious due to the widespread use of electronic devices, namely those used for communication, computation, and automation, among others. Therefore, with the rapid development in these technologies, there has been an increased need for electromagnetic shielding in the radio frequency (RF) region. As one of the basic areas of research for improving the electromagnetic environment, the present authors have developed a slit carbon plate as an RF electric shield that displays orientation characteristics in the shielding results. Little is known, however, about the orientation characteristics found in the RF electric shielding degree SDE of the slit carbon plate. The present authors examine and clarify the orientation characteristics found in the RF electric shielding effects of the slit carbon plate. Experimental results show the dependencies of the orientation characteristics on the length and width of the slit. For reference, the orientation characteristics found in the RF magnetic shielding are also shown.
We have carried out the project for the useful utilization of the remaining rice hull as an industrial carbon material. The rice hull carbon (RHC) powder is manufactured by carbonizing in a nitrogen gas atmosphere at high temperature, then crushing and sieving. The rice hull has a natural porous structure. The diameter of the unit cell is about 10μm. The porous structure retained even after the carbonizing and crushing. The composite material comprised of the RHC and Ethylene Propy -lene Diene Methylene linkage rubbers is manufactured by molding and vulcanizing. In this study, the characteristic of electromagnetic wave absorption (reflectivity) was measured in frequency band between 50MHz and 8GHz for the composite material. The composite material possessed a high characteristic of electromagnetic wave absorption for 2GHz-8GHz. The characteristics were further affected by the test piece thickness and theRHC powder content.
The anatase titanium oxide (TiO2) powders were coated on the woodceramics, which were made from radiata pine wood fiberboards carbonized at 923 K, by means of three electrodes type-plasma thermal spraying in air, in which plasma was ejected from each electrode. Water-resistant and photocatalytic performances of TiO2 coated woodceramics were investigated. Both the rutile and the anatase TiO2 were produced after thermal spraying. A lower power thermal spraying produced much amount of anatase TiO2. The water-resistant performance for the woodceramics was improved by thermal spraying and thermal spraying with a lower power much improved this performance. The photocatalytic performance determined from concentration variations of ethanol in a vessel during an ultra violet light exposure to the woodceramics indicated that the concentration decreased much faster (about 85 % decrease in 4 h) for the woodceramicas after thermal spraying. It is indicated that photocatalytic performance was improved by thermal spraying.
Recently, the generation of poisonous substances, such as formaldehyde, from adhesives or paints used for interior finishing projects has become a serious problem. Dust and cutting chips produced while working with woodceramics (WCS) are currently put into disposal. This study aimed to determine a way to recycle dust and cutting chips. The authors focused on the excellent gas adsorptivity of WCS, and attempted to use these materials in construction. Several paints were prepared to adsorb poisonous substances in the air to prevent sick house syndrome. A large amount of wooden building materials, from which WCS are produced, is discharged from construction sites every day. Therefore, if they can be reused as construction materials, one of ideal recycles can be achieved. Thus, WCS have great potential to be used as eco-friendly materials.
In this research, we studied the characteristics of the carbon electrode from carbonized wood and its influence on the performance of Polymer Electrolyte Fuel Cell (PEFC). The carbon electrodes were made by pulse current sintering 32-45 μm wood charcoal powder at 800, 1000 and 1200℃ under vacuum. The microstructures of carbon electrodes were observed by scanning electron microscopy (SEM), and the electrical conductivity of carbon electrodes was measured at room temperature by a four-probe-method. The evaluation of the performance of current-voltage was conducted in a single cell of PEFC with carbon electrodes. The electric conductivity increased slightly with the sintering temperature. The current-voltage measurement provided an overall quantitative evaluation of the fuel cell power density. A maximum power density of 0.0079 W/cm2 was obtained in the carbon electrode sintered at 800℃. It can be considered that the porous structure of carbon electrode affects the power density.
Soy hull is an agricultural by-product, and has been almost always recycled as an animal fodder for many years. Therefore, a new effective function has been studied for an industrial material. For example, the authors have investigated the soy-hull carbon (SHC) particles as a functional filler for rubbers and plastics. The SHC particle is manufactured by carbonizing the dehydrated soy hull in nitrogen gas atmosphere at high temperature. The SHC particle, consequently the porous carbon particle in which the natural porous structure retains. In this study, the characteristic of the electromagnetic shielding was investigated for the SHC/EPDM composite, which was prepared by kneading the SHC particle with the ethylene propylene diene methylene (EPDM) rubber. The degree of the electromagnetic shielding (SE) of this composite with SHC particle of 400 mass% was found to show a relatively-high value in the frequency region from 50 (SE:40dB) to 150 (SE:30dB). The degree of the absorption (RD) for electromagnetic wave was furthermore, depended on the amount of the SHC particle content, and was shown the high value (RD:-18dB) under the high frequency of 6.5 GHz.
Compressed wood is the material densified by the heat-treated condition with high temperature. The mechanical compression property was examined by using the Japanese cedar (Cryptomeria japonica D.Don) compressed into different density, and the change of elastic-plastic behavior on the compressive deformation was investigated. The results are summarized that the plastic region before reaching to the maximum stress of the stress-strain curves in the compression test decreased with the larger compression ratio. The other compression property was also obtained from the surface hardness test, and the index of the elastic-plastic behavior changed from plasticity to elasticity in condition of larger compression ratio. From these results, it was suggested that the plastic behavior with yielding in the mechanical property of the compressed wood was affected by densification of wooden porous tissue, and that the compressed wood could obtain the higher strength and hardness.
Hydrogen desorption properties of woodceramics, made from radiata pine wood fiberboards carbonized at 923 K and 1473 K, hydrogenated at a temperature of 303 K at an initial hydrogen pressure of 4 MPa, were investigated by means of thermal desorption spectroscopy. Hydrogen desorption initiated at temperatures of more than 750 K, and the accelerated hydrogen desorption occurred at about 1200 K for woodceramics carbonized at 923 K, but almost no hydrogen desorption was observed for those carbonized at 1473 K. Deposition of magnesium (Mg) enhanced the hydrogen absorption and desorption for woodceramics carbonized at 923 K. The activation energy of hydrogen desorption for woodceramics carbonized at 923 K with and without optimal amount of Mg was about 176 and 130 kJ/mol, respectively. No hydride (MgH2) formation was observed for the woodceramics deposited with Mg after hydrogenation.
Although lignin is the most abundant natural phenolic polymer, its phenol activity is extremely low. Because most phenolic hydroxyl groups of lignin precursors were etherified in the biosynthetic process. In the present work, successive cleavage of ether linkages of lignin was carried out Lignophenols synthesized from native lignins through the phase-separation process were depolymerized under the mild alkaline condition. The guaiacyl and syringyl aryl coumaran dimmers were isolated from the hardwood lignocresol treated with 1.0 N NaOH in 21% and 7.4%, respectively. Demethylation of methoxyl group in the syringyl aryl coumaran dimmer was carried out using boron tribromide. The pyrogallol type and 3-methoxy catechol type aryl coumaran were detected with LC/MS analysis. The pattern of demethylation of methoxyl group in the syringyl aryl coumaran dimmer was controlled by lewis acid treatment condition.
Hinoki Cypress (Chamaecyparis obtusa)-lignophenol (p-cresol type, HCLC), which is directly and quantitatively synthesized from wood through the phase-separation system, hydroxymethylated HCLC (HCLC-HM) and polymerized HCLC-HM by heat-set (HCLC-HM-P) were used as materials for photo-sensitizers for nano-porous TiO2 electrodes. In order to investigate influences of structural features of lignophenol derivatives, HCLC, HCLC-HM and HCLC-HM-P were reacted under alkaline conditions at 140℃ (neighbouring group participation) and 170℃ (arylmigration). After these derivatives were investigated by ionization difference spectra using UV-Vis, FT-IR, 1H-NMR and GPC, all derivatives were used as photo-sensitizers. There were different tendencies of HCLC from both HCLC-HM and HCLC-HM-P derivatives. As both HCLC-HM and HCLC-HM-P derivatives kept their polymeric structures, not only arylcoumaran or stilbene but also quinoid type structures acted as good photo absorbers. Based on these results, HCLC-HM-P-TiO2 electrodes polymerized directly demonstrated Voc = 0.48 V, Isc = 4.00mAcm-2, FF = 0.61 and η = 1.06 % under 100.0 mWcm-2 of visible light irradiation. Especially Isc was drastically improved. Moreover hardwood lignophenol showed same tendency.
Separations of Hinoki cypress (Chamaecyparis obtusa)-lignophenol (p-cresol type, HCLC), which are phenolic lignin-based polymers derived directly from lignocellulosics through the phase-separation system, by molecular weight using diethylether (EtOEt), cyclopentylmethylether (CPME), tert-Buthylmethyether (TBME) and EtOEt / CPME (1 / 1, v / v) in ordinary purification processes were carried out. After purification, each lignophenol showed different purification yields: HCLC-E, HCLC-C, HCLC-T and HCLC-B showed 63.7 %, 50.3 %, 71.0% and 62.8 %, respectively. These HCLC samples showed different average molecular weights estimated by GPC. To begin with number average molecular weight (Mn) were 7 870, 9 960, 11 850 and 8 920, respectively. Next, weight average molecular weight (Mw) were 17 960, 22 510, 24 770 and 20 370, respectively. These HCLC samples showed almost same chemical properties such as appearance, solubility for solvents. Moreover same structural features were confirmed by FT-IR and 1H-NMR. Since these HCLC samples also showed almost same thermal properties, there are just a little difference for 5 ℃ on TMA. In conclusion, Molecular weight separation can contribute to not only new advanced chemical modifications for lignophenols, but to investigate new structural features of both lignophenols and whole native lignins in ligunocellulosics.
Two syntheses of novel lignophenol (LP) derivatives via hydroxymethlylated (HM) lignophenol (p-cresol type) under conditions of the phase-separation system were carried out. First, brush-type derivatives were carried out using HM-Western Hemlock (Tsuga Heterophilla)-lignophenol (p-cresol type, HMLC1) as benzyl compounds. Resulting derivatives were obtained with high yields. Due to high reactivity and high affinity between p-cresol and HMCL1, there are no influences with or without reacting supports. Resulting LC2, LC3 and LC4 showed almost same characteristic properties as LP estimated by 1H-NMR, TMA, GPC. Secondly, bulky alkyl phenols were also tried to apply for second grafting phenols to HM-Hinoki cypress (Chamaecyparis obtusa)-lignophenol (p-cresol type, HM-HCLC1). Without vanishing reaction-supports (pulp, freeness100), all derivatives were aggregated. On the other hand, using reaction-supports, 4-sec-buthylphenol (4SBP), 4-(1,1,3,3-tetramethyl)buthyl phenol (4TMBP) and 4-pentylphenol(4PP) generated derivatives with 47.6 %, 25.4 % and 59.4 % yields, respectively. A part of derivatives were dissolved into purification solvents such as EtOEt. Resulting derivatives were estimated by GPC, TMA and 1H-NMR.
In the food industry, it is hoping high value-aided product and the increase in efficiency of food processing. On the other hand, we get an experimental result that the load of the shock wave improves an extraction of food, and soften food. We tried to examine the effectivity of the shock wave as pre-processing for freeze-drying from the result in permeation character seen in the radish and so on. In the case of freeze-drying , the object tends to be limited to the small or thin one with size, from the sublimability in processing, the performance in case of the restoration and the viewpoint of the cost performance ratio. We report the result that shock wave loading was done to shrimp as pre-processing of freeze-drying.
We carbonized the wood waste generated in Shimane Prefecture into humidity-controlling charcoal for use in housing and examined its properties. Though the moisture adsorption isotherm curve of the wood waste was a reverse S-shaped sigmoid curve, that of the charcoal produced was an S-shaped sigmoid curve. This suggests the possible presence of new mesopores (2-50nm) resulting from carbonization. As the relative humidity increased, the percentage of moisture retained by the charcoal in the process of moisture adsorption and desorption increased, but the overall amount slightly decreased.
As a replacement for oil burning boilers used for out-of-season culture in greenhouse, we have developed a new-type greenhouse heating apparatus using woody biomass, which is lumber from thinning, since 2002. The result of this research will be reported in this paper. We have obtained a basic patent on the heating apparatus in 2007 (patent no. 4048488: application in 2003).
Bending creep tests for sugi (Cryptomeria japonica D.Don) glulam with extremely low Young's modulus laminae (3-4GPa) for the inner layer, along with the tests for hybrid glulam with the Douglas-fir (Pseudotsuga menziesii Franco) laminae (14-15GPa) for the outermost layer and the sugi laminae including 3-4GPa laminae for the inner layer, have been carried out since October, 2005. For the test, eight different composition glulam beams with the dimensions of 105mm in width, 210mm in depth and 3980mm in length were prepared. The results are summarized as follows. (1)There was no big difference between the Young’s modulus or bending creep of glulam with L30 (Laminae with 3-4GPa Young's modulus) for the inner layers and that of glulam with L50 (Laminae with 5-6GPa Young's modulus) for the inner layers regardless of the glulam types. (2)Hybrid glulam with sugi laminae for the inner layers and the Douglas-fir laminae for the outermost layers showed higher Young’s modulus and lower creep deflection than the glulam composed of only sugi laminae. However there was no big difference between their relative creep in 50 years, showing the values of approximately “2”. (3)The relation between the change of humidity and that of creep deflection was not clear for the symmetry composite glulam, while it was very clear for the asymmetry one.
Recent increases of allergenic diseases are tremendous. Multiple chemical ingredients may possibly be the allergens or deteriorants. We chose the daily used products mainly applied on the skin. This paper shows the safe and proper application of Hinokithiol as for the antiseptics and preservatives. Hinokithiol (synthetic one, and natural one derived from Aomori-Hiba dissolved in alcohol and Tween, whose concentrations were 0.1%, 0.05%, 0.005%) were patch-tested on 15 healthy adults. Stimulation Indices (SI) were analyzed both after 48 hours and 72 hours. Synthetic Hinokithiol showed the mean SI 11.6 after 48 hours and 4.5 after 72 hours. Natural Hinokithiol dissolved in alcohol showed SI 6.6 after 48 hours and 2.2 after 72 hours. SI by Hinokithiol dissolved in Tween showed 0. For the daily use of products applied on the skin, natural ingredients rather than artificial (synthetic) ones are safer for the skin, especially for allergic patients.
The new methods to utilize the essential oil, especially taken from hinoki (Chamaecyparis obtuse Endl.) and eucalypt (Eucalyptus camaldulensis Dehnh.) were developed in order to raise the total value of hinoki and eucalypt woods. Evaluation and value-added utilization of the essential oils was carried out concerning the chemical recycling of expanded polystyrene (EPS) with essential oil and creating the antifungal and antitermitic agents, cleaning and detoxifying the diesel exhausting gas with hinoki oil fumigant, functional fragrance for human physiological behavior controlling and so on.
A cellulose/copper blend was prepared by a mechano-chemical treatment using a high-speed ball mill called a planetary mill. Cellulose and copper in the blend were mixed in the submicron scale, as observed by scanning probe microscopy using the surface potential microscopic mode. The treatment made the cellulose crystal almost amorphous while the molecular weight of the cellulose retained 70% of its original value. X-ray diffraction patterns of the copper remained unchanged. Removal of cellulose from the blend by firing or enzymatic decomposition yielded porous copper, the surface area of which was 18 m2/g. The copper fragments appeared not to be isolated but rather were connected to each other at junction points. Such a porous structure must prevent cohesion of each metal fragment to retain its effective surface area. Many nano-metals have a problem, in that the cohesion of the particles decreases their apparent surface area resulting in a decrease in the efficiency for their practical use. Therefore, if porous metals prepared by this method are applied as catalysts or electrodes, a high efficiency can be expected.
In this study, the structral characteristics of bamboo lignophenol were discussed in detail. As a part of p-hydroxyphenolic units (H units) esterified to native core lignin still remained in ligno-p-cresols, the separation of H units from core lignin has been done in alkali conditions. The structure analysis of hydrolyzed H units is done with UV spectroscopy measurement(UV), Fourier Transform Infrared(FT-IR) etc.. They are composed of p-coumaric acid, ferulic acid and 4-hydroxybenzoic acid. p-Coumaric acid has antioxidant properties; ferulic acid, being highly abundant, may be useful as a precursor in the synthetic chemistry industry; p-hydroxybenzoic acid is primarily known as the basis for the preparation of cosmetics. That is, p-coumaric acid and ferulic aicd and p-hydroxybenzoic acid are important as the industrial raw materials such as the medicine, the spices, and cosmetics. Therefore, the potential of bamboo forest as a sustainable molecule forming fields can be evaluated through the phase-separation system by the performance analysis on a molecular refining characteristics.
Alpinia zerumbet is a perennial plant growing widely in the subtropical and tropical regions. Alpinia zerumbet leaves and rhizomes have been extensively studied for their chemical compositions and biological activities. It is traditionally used for the treatment of cardiovascular hypertension and as an antispasmodic agent [1-4]. Kaoliang is another kind of lignocellulose, it has been widely used as natural dyes in the coloring of foods, clothes, and cometics. The main components of Kaoliang color have been reported to be apigeninidin and luteolinidin , however, the structures of other compounds present in the colar have not been elucidated clearly until now . Bagasse is the fibrous residue remaining after sugarcane or sorghum stalks are crushed to extract their juice and is currently used as a renewable resource in the manufacture of pulp and paper products and building materials [7-8]. In this study, lignocellulosics characteristics of alpinia zerumbet, kaoliang and bagasse were investigated to compare with other graminae plants through the phase-separation system.
In order to achieve sustainable conversion of lignocellulosics through the phase-separation process, p-hydroxybenzoic acid (p-HBA) attached to core lignin through ester linkage was used as a reagent for lignin conversion. During the phase-separation treatment with p-HBA, the viscosity of reaction mixture was higher, compared with the phase-separation treatment with p-cresol. By centrifugation of the reaction mixture, the thick interfacial solid materials were formed. The yields of lignophenol, its low molecular weight fraction (separated to the organic layer) and the interfacial solid fraction were about 30%, 30% and 40%, respectively. In case of phase-separation treatment with p-cresol, the yields of lignophenol and its low molecular weight fraction (separated to the organic layer) were about 73% and 27%, respectively. The peak ratio of phenol to guaiacol plus syringol in the pyrogram of lignophenol (p-HBA type) was higher than those of lignophenol (p-cresol type) and Klason lignin. The peak of non-conjugated carbonyl group in the FT-IR spectrum of lignophenol (p-HBA type) was higher than that of the material synthesized without p-HBA. These results indicated that p-HBA was grafted to EFB lignin. The lignophenol (p-HBA type) had higher thermal stability, compared with lignophenols (p-Cresol type). The interfacial solid material between the organic and aqueous layers had higher thermal stability than sulfuric acid lignin. These results suggest the formation of lignin network through p-HBA.
Lignin is one of the most abundant renewable materials. It has perfect biodegradability in soil. This biodegradation proceeds oxidatively and reductively. In order to utilize along the material flow in the ecosystem, it is important to obtain information for oxidative and reductive responses of lignophenols, which were synthesized through the phase-separation system. Lignocresol was synthesized from Hinoki cypress (Chamaecyparis obtusa) through the phase-separation system with 72% H2SO4 and p-cresol. Responses under both oxidation and reduction environments were estimated by FT-IR, TGA and TMA. Both lignocresol and wood meals were oxidized with sodium periodate. FT-IR spectra of oxidized lignocresol indicated the formation of muconic acid type structures. FT-IR spectra of lignocresol derived from oxidized wood meals indicated the phenolation of conjugated carbonyl structures. Thermal stability of lignophenols was improved by the reduction treatments with sodium borohydride.
The exhaustion of petroleum oil has been concerned as the consumption of them increases. In response to the trend, biomass resources, in particular lignocellulosics, recently attracts a lot of attention as a substitute for petroleum oil. The phase-separation system accomplishes conversion and separation of lignocellulosics into both carbohydrates and lignin based polymers by the hydrolysis of carbohydrates and the phenolysis of lignin. Through the system under typical conditions, native lignin is converted into linear type polymer (lignophenol) with p-cresol. In this study, the phase-separation treatments with both p-coumaric acid (CA) and ferulic acid (FA) were carried out. The lignin derivatives with CA and FA were distributed into the organic and interface layers, termed L-CA/FA and I-CA/FA, respectively. Through the treatments with CA and FA, most part of native lignins were derived as I-CA or I-FA, having black color and poor solubility. The FT-IR spectra of these derivatives showed bands at 1715 and 1610 cm-1 assigned to unconjugated and conjugated carbonyl groups, respectively. These results suggested that lignin derivatives were derived by rearrangement of lignin polymer network with CA or FA.
CO2 adsorption/desorption on zeolite X and mesoporous silica (MCM-41) was examined under high pressure up to 950 kPa for carbon capture and storage (CCS). The pressure swing adsorption (PSA) method for CO2 separation and capture was used, because of its energy efficiency. In the range of 100-950 kPa, the amounts of CO2 adsorbed on MCM-41 and zeolite X were 14.6 wt% and 5.4 wt%, respectively. The amount of CO2 adsorbed on MCM-41 was 2.5 times greater than that of zeolite X with respect to atmospheric pressure.
We tried to achieve artificial photosynthesis systems by using gel to generate hydrogen when visible light and water are supplied. Three types of gels involving electronic transmission circuit with sensitizer, electron acceptor and catalyst were designed and the amount of generated H2 gas was measured. In the gel systems, hydrogen was generated more efficiently than in the solution systems, and all the functional groups constructed in the gel network worked effectively and cooperated each other to generate hydrogen.
Aqueous polyaniline (PANI)/poly(4-styrenesulfonic acid) (PSS) was prepared by chemical oxidative polymerization in PSS solution. The electrochemical, spectroscopic and electrochromic (BC) properties of PANI/PSS spin-coated films have been investigated. The EC devices consist of emeraldine salt (ES) form of PANI/PSS films on the both of display and counter electrodes. Since ES can be oxidized or reduced to produce pernigraniline (PS) or leucoemeraldine salt (LES), respectively, each reaction takes place at the both electrodes and such a low driven voltage of 0.8 V has been achieved. The color of the display electrode shows green at no bias and is turned to dark blue at the bias. The EC properties, such as contrast and response time, were characterized.
Sputtering In2O3-ZnO on the glass substrate by the DC magnetron method and annealing, granular films were obtained. Controlling the carrier density by the frequency and the power of the light, the carrier density and the mobility were measured by the Hall effect for the high resistance films (180kΩ - 32GΩ). For the samples with the ZnO concentrations 0, 0.5% and 1% (wt), the mobility increases with the carrier density. For the samples ZnO 2% and 3%, the variation of the mobility is relatively small.
Highly transparent, luminescent, chemically pure and biocompatible zinc oxide (ZnO) nanoparticles (NPs) without any surfactants were synthesized by liquid phase- pulsed laser ablation (LP- PLA) of sintered ZnO pellets. Transmission electron microscopic study confirms the formation of crystalline ZnO nanoparticles. The size of the nanoparticles increases when oxygen is bubbled in the liquid during ablation and it remains same on bubbling with nitrogen. The yellow luminescence from ZnO NPs is due to the oxygen vacancies. The emission color can be tuned from yellow to bluish violet by suppressing the oxygen vacancies on bubbling oxygen during the ZnO ablation. The NPs were also grown by LP-PLA under surfactants free acidic and basic medium and the surface charge of the NPs provided the repulsive force between NPs which suppressed the growth through coagulation. These luminescent and nontoxic ZnO nanoparticles will find applications in biomedical imaging and cancer detections.
It was attempted to switch the wettability of a glass surface by modification with the thermoresponsive polymer poly(N-isopropylacrylamide) (PNIPAAm). To strengthen the PNIPAAm layer, the polymer was fixed in a silica gel matrix by a sol-gel method and coated on a glass plate. The wettability of the silica-PNIPAAm composite layer was evaluated by contact angle measurements. The effect of silica on the wettability was investigated by altering the PNIPAAm/silica molar ratio. The effect of surface roughness on the contact angle was also evaluated using atomic force microscopy (AFM). The wettability of the surface drastically dropped by elevating the temperature from 305 K to 313 K through the lower critical solution temperature (LCST) of PNIPAAm.
Spherical C/LiFePO4 cathode powders were successfully prepared by spray pyrolysis. The saccharides such as monosaccharide and disaccharide or organic acid were used as carbon sources. SEM observation showed that they had spherical morphology with particle size of about 1μm. XRD analysis revealed that the olivine phase was obtained by heating at 700℃ under the atmosphere of argon/hydrogen (5%). Electrochemical measurement revealed that the rechargeable capacity of C/LiFePO4 cathode was significantly improved by the addition of carbon. The use of sucrose was most effective for the high rechargeable capacity and cycle stability.
An electron spin resonance analysis confirms that an atomic nitrogen is encapsulated inside a sublimated fullerene (C60) molecule in a radio frequency (RF) discharge plasma. It is observed that the electron beam superimposed RF plasma whose parameters are easily controlled has remarkable effects on the synthesis of the nitrogen atom encapsulated fullerene (N@C60). Optical emission spectroscopy (OES) is used to characterize the nitrogen species in the plasma, and it is clarified that the moderately low gas pressure and high RF power effectively dissociate the nitrogen molecules, resulting in the enhancement of the purity of N@C60.
Bismuth cuprate superconducting film has a large-scale periodicity, supercell, other than an ordinal lattice cell. Although the supercell lies along b axis in bulk material, the structure lies along both a and b axes on thin film and shows asymmetric structure in reciprocal space along c axis. The asymmetric structure was described with triangle function, which modulates the structure to form the supercell. In the terms of the double domain along a and b axes were observed on three dimension X-ray reciprocal space mapping. Bismuth oxide film (Bi2Sr2Ca1Cu2OX) grew with the relation of Bi-2212 parallel to MgO (45° rotation growth), but the bismuth cuprate superconducting film often grows with lateral rotation from 45° growth. To describe such a relation, coincidence site lattice was visually expressed on polar coordinate system.
Magnetization and magneto-resistance ratio (MRR) were measured for (γ'-Fe4N)x(CrO2)1-x granular system between 77 K and 300 K, where x is the mole ratio of Fe4N in the measured samples. The γ'-Fe4N and CrO2 are the ferromagnetic half metals with high Curie temperature and relatively high electrical conductivity. Since the spin polarization coefficient P of conduction electrons is nearly −1 in Fe4N and 1 in CrO2, the various junctions in this system are expected to show the competing tunneling magnetoresistance (TMR) effects. The MRR of this system showed the compensated behavior at x around 0.2, which is the percolation threshold of connectivity of Fe4N grains.
The differential speed rolling (DSR) process has been carried out on a heat-treatable AZ61 magnesium alloy at different rotation speed ratios (RSR). Compared with the normal symmetrically rolled sheet without an inclination of basal pole, the sheets DSR-processed at the RSRs of 1.17 and 1.36 exhibit the inclination of basal pole toward the rolling direction at about 5° and 10°, respectively, while the microstructures show approximately the same grain size of 7 μm. Increasing the RSR leads to the decreases in 0.2% proof stress (YS) and r-value as well as the increases in uniform elongation and n-value. For the sheet DSR-processed at the RSR of 1.36, the ultimate tensile strength (UTS), the YS, the fracture elongation (FE) and the Erichsen value (IE) are 313 MPa, 182 MPa, 24.3% and 4.7, respectively. This IE is higher than that (4.1) of the normal-rolled sheet. The improvement of the stretch formability can be attributable to the texture favored for the basal slip during deformation. After aging treatment, the UTS and the YS further increase to 336 MPa and 208 MPa, respectively, accompanied with a decrease in the FE.
In the conventional preparation processes, a heating substrate should be applied to improve their crystallinity and films are easily peeled from substrates. This research was aimed to prepare TiO2 films on slide-glass substrates at room temperature by using magnetron sputtering method. TiO2 powder was used as a target material. Ar gas was used as a sputtering atmosphere. Variations of crystal property and morphology were investigated as a function of substrate temperature. It was found that Anatase-type films could be prepared at room temperature.