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To obtain information on the environmental impact of materials eluted from volcanic ashes of Mt. Oyama, Miyake Island, which erupted in July 2000, the dissolution behaviours of heavy metals and rare-earth elements from the volcanic ashes were examined. The most important characteristic of the Mt. Oyama eruption is that sulphur dioxide (SO2) gas has been continuously released, and all persons living on Miyake Island have been required to evacuate. To estimate in terms of the volcanic eruption using SO2 gas, the ash nature in Mt. Usu, Hokkaido, was also examined and compared with that in Mt. Oyama. When rain water mixed the ashes, the water from the ashes of Mt. Oyama became acidic because of the sulphuric acid. Therefore, SO2 gas in Mt. Oyama can accelerate the dissolution of protons and heavy metals in the ashes, whereas the rain water in Mt. Usu was not acidic and the dissolution of the heavy metals was not so evident compared with that in the case of Mt. Oyama. With this sulphuric acid, heavy metals suc...

We estimated the current perpendicular to plane (CPP)-magnetoresistance (MR) performance target required for hard disk drives (HDDs) with areal density from 2 to 5 Tb/in2 , considering spin transfer torque (STT) and thermal magnetic noise. It is found that the noise due to STT drastically affects the MR performance target for low resistance area (RA) film. Read elements with higher RA (around 0.1-0.3 ?·?m2 ) are preferable to control STT. In addition, thermal magnetic noise remained smaller than media magnetic noise for 2 Tb/in2 while it becomes comparable to media magnetic noise for 5 Tb/in2 , suggesting the necessity of a new method to control thermal magnetic noise.

We investigated the current induced magnetization dynamics, so called spin torque oscillation, in magnetic nano-contact MR element with a synthetic antiferromagnetic type spin-valve structure under high in-plane applied magnetic field of 0.9-1 kOe. Very high level oscillation of 18 nVHz-1/2 with narrow FWHM of 12 MHz was observed in the condition of negative applied current where electron-spin is injected from free layer to reference one. Applied current dependency on an oscillation frequency is a blueshift with good linearlity, and same dependency on level and FWHM is almost constant in the range of -10 to -14 mA, while applied field dependency on frequency shows redshift with two different slopes, -2.5 MHz/Oe in less than 1 kOe and -8.7 MHz/Oe in more than 1 kOe which field is smaller than the spin-flop field for the synthetic antiferromagnet, besides very clear and reasonable peak and bottom for oscillation level and FWHM are observed, respectively. It is thought that these magnetization dynamics are originated from synthetic antiferromagnet.

The recovery of metal scrap for recycling contributes to the conservation of natural resources and the construction of a sound material cycle. A dynamic material (substance) flow analysis is useful to understand how and in what proportion materials are used, how they may dissipate into the environment, and how they partition into certain reservoirs (e.g. landfills). So, it enables us to investigate the potentials of metal scrap recovery in the designated area in the future. In this article a dynamic material flow analysis for copper and its alloys in Japan was conducted in order to estimate the stock, the amount of discarded and collected scraps in the future. There was a significant gap between the supply and the demand of scraps in statistics in Japan. The comparison between the estimation and the statistics suggested that this gap was due to the obsolete scraps which were not accounted as a supply of collected scraps. The amounts of collected copper scraps and its alloy scraps were estimated separately from 1970-2005. The results showed that approximately 300 thousand tons of high-purity copper or high copper alloys were recovered with impurities or copper-alloy scraps, which were finally consumed as copper-alloy scraps.

We deposited perpendicularly magnetized Co(∼1nm)/Pt(6nm) bilayers by thermal chemical vapor deposition (CVD) on top of 3nm thick Pt layer using various deposition temperature. Observed Ms increased with the increase of deposition temperature Ts, and reached the value of pure-Co at Ts = 500°C. We measured a (left-handed) negative Dzyaloshinskii-Moriya interaction in CVD films indicating a dominant role of the bottom Pt/Co interface.

This paper proposes a new method for rotation-invariant picture matching using an orientation histogram represented by autoregressive model. An orientation histogram is created through gradient of brightness at each pixel. The orientation histogram intersection (OHI) algorithm is effective for searching rotated patterns in the scene, but it needs time consuming circular shifting operations of a reference orientation histogram. This computational demerit increases when registration accuracy is desired. The proposed method expresses an orientation histogram by an autoregressive model as a closed contour, and it has rotation-invariance as well as OHI and then fast computation can be performed by use of the representation with smaller parameters. Experiments with real pictures show effectiveness of the proposed method.

A series of bulky carboxylates was introduced as a counteranion for N-methylpyrrolidinum salt end groups of poly(tetrahydrofuran), poly(THF), having molecular weights of ca. 5000. 4-(7,7,7-Triphenylheptoxy)benzoate was found to remain intact as a counteranion at ambient temperature but to cause the ring-opening reaction of pyrrolidinium groups at 90 °C to produce poly(THF) with bulky stopper groups in a pure form in 71% yield. The relevant ring-opening reaction also took place in the presence of such macrocyclics as 30-crown-10 and cyclodextrins, but an effective entrapping of cyclic components in polyrotaxanes was not achieved presumably because of the entropic repulsion between the two components.

We have achieved a magnetoresistance (MR) ratio of 7%-10% at a resistance area product (RA) of 0.5-1.5 Omegamum2 by ferromagnetic FeCo nanocontacts in Al nano-oxide-layer (NOL) with current-perpendicular-to-plane spin-valve (CPP-SV) structure. Conductive atomic-force-microscopy shows clear current-path regions of a few nanometers in size surrounded by the Al-NOL. The MR dependence on resistance area product (RA) is well explained by the current-confined-path model assuming that the spin-dependent scattering has an FeCo nanocontact origin, different from tunnel magnetoresistance (TMR). Resistance increases with increasing bias voltage, indicating joule heating by high-current density in nanocontacts, in contrast to TMR. The MR origin is mainly interpreted as spin-dependent scattering due to domain wall formed at ferromagnetic nanocontact

The optical absorption mechanism of a semiconductor optical modulator with electron-depletion absorption control was theoretically and experimentally investigated. In the doped direct transition semiconductor material, optical absorption increased when electrons were depleted. In the region where electrons are depleted, the number of electrons in the conduction band and holes in the valence band decrease, the impurity energy level shifts due to the decrease of the screening effect and the internal electric field strength increases. Because of these phenomena, the band-to-band electron transition probability increases. As a result, the optical absorption increases in the modulator.

We have compared the magnetoresistance (MR) performance of current-confined-path (CCP) current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) spin valve films with a nano-oxide-layer (NOL), made between natural oxidation (NO) and ion-assisted oxidation (IAO). For the NO, an MR ratio was only 1.5% at an RA of 370 m/spl Omega//spl mu/m/sup 2/, whereas for the IAO, an MR ratio was greatly increased to 5.4% at an RA of 500 m/spl Omega//spl mu/m/sup 2/. Fitted data by the Valet-Fert model showing larger MR enhancement effect by the IAO is explained by the improvement of the metal-purity of the Cu inside the CCP structure. By further improvement of metal-purity of the Cu, a large MR ratio of more than 30% can be expected at a small RA of 300 m/spl Omega//spl mu/m/sup 2/. The CCP-CPP spin valve film is a promising candidate for realizing high-density recording heads for 200 to 400-Gbpsi recording.

We propose tri-magnetic terminal-based non-local spin valves (TM-NLSVs) for lateral structures. A lateral structure has dual spin injector terminals with an anti-parallel spin configuration. The accumulated spin is detected as the voltage between the free layer and one side of the spin injector. Numerical investigation revealed that the output voltage of the TM-NLSV is 2.4-fold higher than that of the conventional four-terminal structure. A further 3.7-fold increase is expected by increasing the injector area by a factor of 9. These results indicate the possibility of obtaining an output voltage that is almost the same as that of conventional (non-lateral) spin valves.

Cultivation conditions ofPseudomonas vesicularisvar.povalolyticus PH, a PVA degrading bacteria, were investigated in order to study its application to waste water treatment. The optimum pH and temperature for both growth and PVA degradation of PH strain were determined to be 7.0-7.5 and 30-35°C respectively. However, effective PVA degradation was also observed at 37.5°C. PH strain grew well in proportion to the PVA concentration within 500-2000mg/l range. PH strain was also able to utilize glucose, pyruvic acid, fructoligosaccharide, and glutamic acid as sole carbon sources. Particulaly, high PVA degrading activity was shown when grown on glutamic acid, pyruvic acid or complex media. Magnesium or calcium was the key mineral for the growth of PH strain. Especially Magnesium had high ability to promote good growth. If symbiotic bacteria coexisted with PH strain, it could grow on PVA without any growth factors.

活性汚泥微生物による有機物除去と硝化・脱窒の各反応を, Michaelis-Menten修正式を用いた同一の動力学ベースから整理し, その動力学的な論述を試みた.また, これらの反応動力学を用いて, 活性汚泥法の制御動力学式を誘導し, その動力学的制御の可能性を論ずるとともに, 嫌気・好気式高濃度活性汚泥法の動力学解析を通して, その最適設計に関する計算法を導出し, 動力学式パラメーターの相互関係を明らかにした.

Experimental investigations were carried out on the immobilization effect of activated sludge in case of supplying Xonotlite continuously to the aeration basin, which was calcium silicate hydrate.Initial diameters of activated sludge floc were about 30-100μm. But, the floc diameters of activated sludge were about 500-1000μm after 3 weeks, increasing gradually during the experimental period. It was shown obviously that Xonotlite was to act as the bridge-building material and to promote the binding immobilization of activated sludge from microscopic observation.The accumulated amount of Xonotlite in activated sludge was derived from the mass balance in aeration basin. It was suggested that set values of both sludge retention time and influent Xonotlite were very important, applying its formula to the experimental results.Moreover, it was considered that theoretical and experimental investigations on the influent inorganic matter affecting to activated sludge were significant problems in future.

PVA硼酸法による下水活性汚泥の包括固定化ビーズを用いた低濃度汚染水の有機成分, アンモニア性窒素およびフミン酸の分解・除去能を種々実験的に検討したところ, 約61～75%の安定したTOC除去率が得られ, またビーズ充填率および水理学的滞留時間の増加に伴い, NH4-N・フミン酸の各除去率は増加し, さらに曝気脱窒によるNO3-N除去も期待できることが示唆された.一方, 固定化ビーズを硫黄補填好気-嫌気ろ床法に適用したところ, TOC・NH4-Nの効率的な除去とフミン酸の吸着除去ができることが明らかとなった.しかし, 嫌気槽での硫黄脱窒反応を促進するには, 好気槽からの持込み溶存酸素に注意する必要があることがわかった.PVA硼酸固定化ビーズは, 耐久性に優れているので, 低濃度汚染水の高度処理には実用性の高い固定化担体であるといえる.

We have succeeded in designing, fabricating, and testing self-alignment trench-pole write heads. 1 /spl mu/m narrow track heads were fabricated by a newly developed self-alignment trench process and showed large overwrite of over 40 dB for low-noise high coercivity media with Hc=2800 Oe, even with a large throat height of 3 /spl mu/m. This trench pole writer showed high potential for submicrometer narrow track application.

A large output voltage of 0.7 mV at 1 mA charge current is demonstrated for all-metallic nonlocal spin valves using Co2(FeMn)Si Heusler alloy and Cu with a junction area of about 50 nm2. The output is attributed to the junction size reduction as well as to the high spin polarization in the Heusler alloy. An analysis using a one-dimensional model reveals that the spin diffusion length in the Cu layer shows no clear degradation even in the case of a 50 nm2 junction. When the junction is reduced further to 10 nm2, an output voltage of about 10 mV is expected.

In relation to theoretical predictions on the importance of randomness at the interface to determine the cause for giant magnetoresistance, argon acceleration voltage (VB) in ion beam sputtering was changed for preparing a set of CoxFe1−x/Cu multilayers. We found that the magnetoresistance as quite sensitive to the argon acceleration voltage and had a maximum around VB=600 V. Perfect antiferromagnetic coupling of the CoxFe1−x layers via thin Cu layers and the oscillation behavior of this indirect exchange coupling with a 12 A period were observed for VB=600 V. These results suggest the importance of the interface state for giant magnetoresistance in multilayers. We also found that a small saturation field can be induced, which can be explained by the metamagnetic transition associating the relation of Ku≳J/tCoFe.

We investigated the microwave oscillation of resistance due to spin-transfer torque in ferromagnetic nano-contact spin-valves under an external in-plane magnetic field. We varied the direction of the external magnetic field and therefore the relative angle, θ, between magnetizations of the free and reference layers. We showed that the level of microwave oscillation takes a maximum value at around θ = 140°. We also showed that the microwave oscillation frequency increases with increases in the applied direct current.

We have realized a large magnetoresistance (MR) ratio of 10.2% by current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) spin-valve films having current-confined-path (CCP) structure formed by AlCu-NOL (nano-oxide-layer). CPP-GMR with conventional Co90Fe10 pinned and free layers showed an MR ratio and a ΔRA (the change of resistance area product) were 4% and 20mΩμm2, respectively, at a small RA (resistance area product) of 500mΩμm2. By replacing the Co90Fe10 layers by Fe50Co50 layers both for pinned and free layers, we have successfully realized a MR ratio and a ΔRA of 7.5% and 37.5mΩμm2, respectively, at a small RA of 500mΩμm2. Moreover, a large MR ratio of 10.2% and a large ΔRA of 418mΩμm2 were realized at a relatively large RA of 4100mΩμm2. This large MR ratio by using Fe50Co50 layers was due to a larger spin-dependent interface scattering factor γ of 0.72 for the interface between Fe50Co50 and Cu, which was improved from a γ of 0.62 for the interface between Co90Fe10 and Cu.

The nitride layers were prepared by direct thermal nitridation of 6H-SiC substrates at 1200–1570°C in a NH3 atmosphere. The layer was characterized by using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Raman scattering spectroscopy. The thickness of the nitride layers prepared at lower than 1400°C was estimated to be less than 10 nm. The higher nitridation temperature resulted in the formation of a thicker surface layer. XPS measurement showed that the surface layer was composed of N, Si, C and O. Peaks corresponding to α-Si3N4 were detected in the Raman spectra and the XRD patterns of the sample prepared at higher than 1500°C, indicating the crystallization of the nitrided layer.

Degradation rates of salicylate and phenol by Pseudomonas putida PpG1064 carrying the nahG gene on a multicopy plasmid were compared with those in NAH-carrying P. putida . Degradation rates of salicylate and phenol and the growth rate of the recombinant were higher than those in NAH-carrying P. putida in SP medium. The catechol 1,2 oxygenase activity of the recombinant in Sp medium was about twice that of the catechol 2,3 oxygenase and catechol 1,2 oxygenase activities of NAH-carrying P. putida . It was suggested that in simultaneous degradation of phenol and salicylate, the recombinant stimulated its ortho cleavage pathway and attained the higher degradation rates and growth rate.

活性汚泥法の浄化機能を数学的, 動力学的に解析し, それをもとにした合理的な設計, 運転操作のための動力学式が, これまで多くの研究者により提唱されている.しかし, この動力学式に及ぼす環境因子の影響についてはまだまだ十分研究されてきたとはいえず, 水温の影響もその大きな因子の一つである.そこで, 水温10～40℃で活性汚泥法の連続実験を行い, 一次型動力学式パラメータに及ぼす水温の影響について解析し, 次の結論を得た.ts (活性汚泥の平均滞留時間) が2～10日では, 各動力学式パラメータに及ぼす水温の影響は非常に小さかった。tsが0.125～1日では, 次のようになった.水温が20～40℃において, 基質除去速度定数についての水温の影響の大きさを示すアレニウス式の活性化エネルギーの値は9, 860ca1/molであり, また, 自己分解速度係数についての活性化エネルギーの値は7, 530cal/molとなり, 水温の影響は比較的大きかった.しかし, 収率係数の値はほぼ同程度の値で, 水温の影響は小さかった.水温が10℃においては, tsが短くなるにつれパラメータ値が変化し, 水温の影響は大きいと考えられた.

Experimental studies were conducted to determine the feasibility of autotrophic denitrification with Thiobacillus denitrificans as a nitrate removal process for wastewater. S0-acclimated activated sludge, which can carry out autotrophic denitrification using S0 as electron donors, was prepared by the fill and draw cultivation method. The kinetic constants for the S0-denitrification reaction using S0-acclimated activated sludge under NO3-N limiting growth conditions were determined to be Y = 0.33 mg-NO3-N and b = 0.058 d−1. High percentages of denitrification (over 95%) and rates of denitrification ranging from 0.19 to 0.24 mg-NO3-N/mg-TOC·d were obtained in the continuous denitrification experiments using S0-acclimated activated sludge.

A new method (polyvinyl alcohol-boric acid method) for an inexpensive and effective immobilization of activated sludge was developed. Using activated sludge immobilized by this PVA-boric acid method, synthetic waste-water was treated at a high loading rate of 0.5-2.35 kg TOC/m(3) day. Total organic carbon and total nitrogen were removed at efficiencies of 93 and 30-40%, respectively. The kinetic constants Y and b for this immobilized activated-sludge process were determined to be 0.594g mixed liquor suspended solids (MLSS)/g TOC and 0.0219 day(-1), respectively. The cost calculation of chemicals required for the immobilization of activated sludge by this PVA-boric acid method was proved to be extremely inexpensive for the immobilization of activated sludge.

The foam produced by Rhodococcus sp. in the aeration tanks of the activated sludge treatment plants was more stable than that formed by N. amarae. The stability was determined from the half time of foam decomposition. The stability depended upon the hydrophobicity characterized by the carbon numbers of mycolic acids. The Hydrophobic strengh of Rhodococcus sp. was higher than that of N. amarae. This was determined by using an index of log p = Po/ Pw, P and P are the partition coefficient of mycolic acid in solvent and water, respectively.

Using the results of a sensory test of drinking water and some findings from the literature, we examined the requisites for tasty and healthy water. It was found that calcium, potassium and silica were correlated to the good taste of water and sulfate and magnesium were factors making water unsavory. We also found that the concentration difference between calcium and sodium was closely correlated to the death rate due to apoplexy and, consequently, the span of life in Japan. From these findings, we derived two equations for indicators of tasty water and healthy water. They were named the O index and K index, respectively, and were expressed as follows; O index = Ca+K+SiO 2 Mg+SO 4 (mg/l) K index = Ca−0.87 Na (mg/l) It has become apparent that tasty water was an O index of over 2.0 and healthy water was a K index of over 5.2. O and K indices were estimated Japanese waters, including representative drinking water, 218 river waters, and famour river waters selected by the Environmental Agency, and these waters were classified as tasty and/or healthy according to the results. This classification seems to be rational because the findings are consistent with everyday experience.

The flow passing through constriction in an open channel is highly three-dimensional. The center flow close to the bed, however, can be analyzed by combining the two-dimensional potential flows and by using the boundary layer analysis already developed by the authors. Although this method is applied successfully in order to calculate bed shear stress along the center line of flow, the calculation is rather tedious, and it is neccessary to know the water stage at least along the center line. Furthermore, it is not possible to analyze the phenomena of flow in the whole domain of the flow. For the practical purposes, the characteristics of flow are investigated by the aid of laboratory experiments and the appreciable results can be obtained based on the hydrodynamic consideration.