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Ti and TiO_2 films were deposited by RF reactive sputtering using a mixed gas of Ar and O_2. TiO_2 films were found to be formed at oxygen flow ratios above 7%. At the critical O_2 flow ratio, the amount of supplied Ti atoms was found to agree with that of O_2 molecules. Above the critical O_2 flow ratio, the amount of supplied O_2 molecules exceeded the gettering effect of the sputtering Ti atoms and oxygen density in the plasma began to increase. As a result, the surface of the Ti target was oxidized and TiO_2 films were formed. The thickness of the oxide film formed on the Ti target increased with increasing oxygen flow ratio and a maximum thickness of 5-6 nm was obtained at oxygen flow ratios of 40-100%., application/pdf

Ferromagnetic (Ga,Mn)As epitaxial layers with zincblende structure have been grown on Si (1 0 0) substrates employing a three-step method using molecular beam epitaxy. Magnetic measurements reveal that the ferromagnetic transition temperature is 48 K for a layer with a lattice constant of 0.567 nm, which corresponds to a nominal Mn composition of 2%. When grown directly on Si without the three-step method, the same set of growth parameters results in a (Ga,Mn)As layer with a ferromagnetic order below 25 K. The difference of magnetic property between these two samples is attributed to the quality of the (Ga,Mn)As layer which originates from the different growth methods.

Pilot plant studies were carried out using actual wastewater to investigate the applicability of a membrane separation activated sludge (MSAS) process to municipal wastewater treatment. A small-scale pilot plant (6.7 m3/day) with immersed flat sheet membrane was operated at the flux of 0.4 m3/m2/day. Continuous operation for 140 days without chemical cleaning was possible. Average Sludge production ratio was about 0.6. No significant difference was observed in the dewaterability between membrane separation activated sludge and conventional activated sludge at the CST test. Large-scale pilot plants (30–70 m3/day) with five types of membrane were also operated. In these plants nitrogen removal by nitrification and denitrification, and phosphorus removal by coagulant addition were carried out. Stable operation with HRT of six hours, flux of 0.4–0.8 m3/m2/day was possible, the average nitrogen and phosphorus removal efficiency being more than 80 and 95%, respectively.

Photoluminescence (PL) spectra, time profiles of PL intensity and PL excitation spectra (PLE) for inter 3d multiplets (3d-MS) transition of Mn2‡ are observed in the semimagnetic semiconductor CdMnTe under high pressures. Those of inter 3d-MS and inter quantum levels (QL) transitions are also observed in quantum wells (CdTe/Cd0.4Mn0.6Te). The decay processes in these excited states are discussed. The decay process to the excited states of infrared photoluminescence is also discussed for various concentrations. In these excited states it is considered that large lattice relaxation is essential.

Time-resolved measurement is performed for photoluminescence around 2.0 eV which originates from internal transition between 3d multiplet states in Mn based semimagnetic semiconductors. Observed emission spectra show red shift with delay time after excitation. Larger shift is observed in the sample with larger width of the emission spectrum, which implies that the shift is caused by the energy relaxation in the inhomogeneous distribution of the Mn energies. To confirm this, we perform simple Monte-Carlo simulation in a wide range of time scale. The results well explain the magnitude of the shift and its logarithmic dependence on delay time. The dependences on excitation energy, temperature and pressure are also investigated.

Objective: Sucrose has been used as an estimate of the extracellular fluid (ECF) volume. This study was designed to examine the hypothesis that the initial distribution volume of glucose (IDVG) correlates with the initial distribution volume of sucrose (IDVS) following volume challenges. Design: Prospective study for comparison of two methods. Setting: Animal laboratory of the University of Hirosaki School of Medicine. Materials and Methods: Ten mongrel dogs of either sex, weighing 8.5-14.0 kg, were the subject of the study. Dogs were anesthetized with pentobarbital and paralyzed with pancuronium. The volume challenge was conducted with 3% dextran in lactated Ringer’s solution 30 ml · kg–1 over 30 min in 10 dogs. Thereafter, the same amount of the fluid was further administered in 8 of these 10 dogs. Before and after each volume challenge, glucose (100 mg·kg–1) and sucrose (100 mg·kg–1) were infused simultaneously over 30 s. The two estimates were calculated using a one-compartment model from repeated measurements of increased plasma glucose and sucrose during postinfusion. Results: A linear correlation was obtained between the two estimates (r = 0.89, n = 28, p< 0.0001). All dogs consistently showed that the IDVG individually followed the IDVS during changes in the latter. Conclusions: Results demonstrated that the IDVG correlated with the IDVS before and after volume changes and support the hypothesis that the IDVG is useful for evaluating the ECF volume status of highly perfused tissues.

Indocyanine green (ICG) has been demonstrated to be a reliable indicator for the estimation of plasma volume in man. Since this dye is bound to plasma protein when administered intravenously, overestimation of the plasma volume would occur during the presence of protein leak from plasma. However, to our knowledge, up to now no report has described whether or not plasma volume determined by the indocyanine green dilution method (PVICG) is clinically significantly overestimated under such conditions. We report two burned patients who temporally had an unusual large PVICG even though other clinical variables did not support the presence of hypervolemia. From the case described it can be concluded that a possible overestimation of PVICG occurs when the vascular permeability for proteins is increased.

We report results obtained by photoluminescence (PL) measurements on zinc blende Cd 1− x Mn v Te thin films. For concentration x > 0.77 a large shift in Mn 2+ PL peak energy to higher energies was observed with increasing Mn concentration. An energy shift in Mn 2+ PL with change in excitation energy, observed in bulk CdMnTe at low temperature, has also been observed in thin films. Inhomogeneous broadening of the Mn 2+ PL in MnTe film is determined to be 32 meV. A high pressure technique was employed to obtain the temperature dependence of the pressure coefficient of the Mn 2+ PL energy in zinc blende MnTe thin film. The results are compared with those of bulk CdMnTe.

The effect of low-temperature annealing on (Ga,Mn)As/GaAs/(Ga,Mn)As trilayer structures is studied. Low-temperature annealing significantly increases the ferromagnetic transition temperature TC of top (Ga,Mn)As layers, reaching as high as 160 K, whereas no apparent effect is observed on bottom (Ga,Mn)As layers. The annealing effect on Be-doped trilayers is also presented.

Using cross-sectional scanning tunneling microscopy (STM), we have investigated the local electronic properties of molecular-beam epitaxy grown GaMnAs layers on a p-GaAs substrate. The STM image shows light and dark areas with the average size on the order of nm. From conductance spectra measured with the STM, the bandgap of the GaMnAs is estimated to be 1.23±0.05 eV. An apparent conductance within the bandgap indicates the presence of hole states in the valence band, which are induced by Mn acceptors. A conductance peak at 0.7 eV above the valence band edge can be identified with electron tunneling into the ionization levels of As antisites.

The relative contribution of voltage-sensitive Ca 2+ channels, Ca 2+ -ATPases, and Ca 2+ release from intracellular stores to spontaneous oscillations in cytosolic free Ca 2+ concentration ([Ca 2+ ] i ) observed in secretory cells is not well characterized owing to a lack of specific inhibitors for a novel thapsigargin (Tg)-insensitive Ca 2+ -ATPase expressed in these cells. We show that spontaneous [Ca 2+ ] i oscillations in GH 3 cells were unaffected by Ca 2+ depletion in inositol-1,4,5-trisphosphate (IP 3 )-sensitive Ca 2+ stores by the treatment of Tg, but could be initiated by application of caffeine. Moreover, we demonstrate for the first time that these spontaneous [Ca 2+ ] i oscillations were highly temperature dependent. Decreasing the temperature from 22 to 17°C resulted in an increase in the frequency, a reduction in the amplitude, and large inhibition of [Ca 2+ ] i oscillations. Furthermore, the rate of ATP-dependent 45 Ca 2+ uptake into GH 3 -derived microsomes was greatly reduced at 17°C. The effect of decreased temperatures on extracellular Ca 2+ influx was minor because the frequency and amplitude of spontaneous action potentials, which activate L-type Ca 2+ channels, was relatively unchanged at 17°C. These results suggest that in GH 3 secretory cells, Ca 2+ influx via L-type Ca 2+ channels initiates spontaneous [Ca 2+ ] i oscillations, which are then maintained by the combined activity of Ca 2+ -ATPase and Ca 2+ -induced Ca 2+ release from Tg/IP 3 -insensitive intracellular stores.

Previously developed theory predicts that, at a given shear rate G, the period of rotation T of a permanent doublet of rigid spheres about the vorticity axis depends not only on the separation distance h between the surfaces, but also on the ability to the particles to rotate relative to each other. Using conventional DLVO theory, these principles were applied to doublets of 2.6-μm diam polystyrene latex spheres in dilute suspensions in Poiseuille flow through 200-μm diam tubes. The range of electrolyte concentration over which doublets having spheres captured in the secondary energy minimum can exist was calculated from the measured ζ potentials and assuming a Hamaker constant A = 0.001 aJ. Accurate measurements of the mean TG ¯ of doublets in the sol were then made in a modified traveling microtube apparatus. The existence of secondary doublets at the predicted [KCl] was confirmed, and the measured TG ¯ found to correspond to h > 17 nm. From the distribution in TG ¯ , the existence of doublets in the deep primary minimum was shown, and from the shift in distribution with [KCl] it was concluded that 0.006 aJ TG ¯ was also measured in the presence of Cat-floc, a cationic polyelectrolyte. A marked decrease in TG ¯ was found, at low polymer concentration due to charge interactions, and at high polymer concentration due, it is believed, to bridging of polymer molecules between sphere surfaces. The significance of these observations is discussed with emphasis given to the usefulness of the experiments in measuring basic parameters governing the stability of colloidal sols.

Summary Reservoir wettability is important to oil recovery by waterflooding and many other oil recovery processes. The difficulties associated with determination of in-situ wettability, together with uncertainties about application of laboratory observations to field conditions, necessitate a more basic understanding of factors that control wettability. We previously reported that the adhesion of crude oil to a solid surface could be related to wettability alteration. In this work, conditions under which oil adheres to a particular solid surface are demonstrated for several crude oils. For a given oil, pH and ionic strength were varied to obtain a mapping of conditions under which adhesion occurs. Results were satisfactorily explained by double-layer calculations in combination with the ionizable surface group model. Lack of adhesion signifies the presence of a stable water film that results from double-layer repulsion between the crude oil and the solid surface.

The rotations of models of rigid and flexible dumbbells suspended in viscous oils were studied in Couette flow. Rigid dumbbells of fixed interparticle distance r were made using 1- to 3-mm-diameter spheres, rigidly coupled or freely rotating, joined by rigid 38-μm-diameter filaments or 100-μm-diameter metal wire. Flexible dumbbells of variable r were made using elastomer filaments of 56-μm-diameter. The translational and rotational motions of the spheres as well as that of the dumbbell axis were recorded on videotape or cine film, and the results compared with theory assuming negligible hydrodynamic resistance of the connecting filament or wire. As predicted, it was observed that, at a given r, the measured dimensionless period of rotation TG of the dumbbells of freely rotating spheres was appreciably greater than that of rigidly coupled spheres. When, due to viscous damping, the sphere rotations were hindered, TG was significantly reduced. The measured dumbbell and sphere angular velocities were in good agreement with theory for dumbbells exhibiting free or hindered sphere rotation. Flexible dumbbells whose spheres and filament were initially positioned in the equatorial plane, adopted a limiting orbit (limit cycle) characterized by a periodically varying r, appreciable bending of the filament, and an increase in TG with increasing G. The measured sphere paths and TG were in fair agreement with theory, although there were significant discrepancies due to the rigidity and hydrodynamic resistance of the filament, especially at low G. The results are discussed in the light of the previously described flow behavior of primary energy and secondary energy minimum doublets of latex spheres, as well as of polymer bridged doublets.

Current-potential and specular reflectivity-potential curves of a Au electrode have been measured in 1 M CHlO4 in the presence of 1·0 × 10−3 M Pb2+. Four peaks were found on a linear sweep voltammogram at potentials more positive than the Nernst reversible potential of Pb0/Pb2+ couple, which are attributed to the Faradaic adsorption of Pb2+. Specular reflectivity-potential curves recorded simultaneously at varied wavelengths gave a clear indication of the adsorption which increased the reflectivity at shorter wavelengths while decreased at longer wavelengths. From the analysis of the current-potential curve of four peaks in relation to the reflectivity change, the following results were obtained: (1) The existence of four peaks on the voltammogram is the indication of four different adsorbed states. (2) The Pb atoms in a submonolayer on Au electrode have rather similar optical properties to those of metallic Pb except for the adsorbed atoms formed at the most potential region. (3) The adsorbed Pb formed at the most positive potential region have the shortest distance to the surface Au atom, and accordingly, have the strongest interaction with the surface.

Publisher Summary This chapter discusses polarographic determination of vitamin K 5 in aqueous solution. 4-amino-2-methyl-l-naphthol hydrochloride is known as a water-soluble vitamin K and is generally called vitamin K 5 (VK 5 ). Because aqueous media under ordinary conditions are commonly used in biological studies, a simple method for the assay of VK 5 under such conditions is desirable. Because VK 5 tends to be oxidized and then hydrolyzed in water, the complete removal of oxygen is necessary for determinations of VK 5 in aqueous solutions. A polarographic technique provides a convenient procedure to fulfill this requirement. In this chapter, the application of direct current (dc) and alternating current (ac) polarography to the microdetermination of VK 5 in aqueous solution present in concentrations as low as the 0.1-ppm range is described. The use of the ac polarographic technique makes it possible to determine VK 5 in a much lower concentration range. The method and procedure of polarography technique are elaborated. A dc polarogram of VK 5 obtained in an oxygen-free base electrolyte solution at pH 5.5 is also shown.

Multiple specular reflection has been used to examine in situ the gold electrode in acid and alkaline solutions. Reflectivity-potential and linear sweep voltammetry curves have been recorded simultaneously. The wavelength dependence indicates that the reflectivity changes with potential arise principally because of penetration of the d.c. electric field associated with the interface into the metal and subsequent interactions with the internal photoelectric effect in gold associated with a 5d to 6s band transition. The present results demonstrate that multiple specular reflection techniques are particularly well suited to in situ studies of the specific adsorption of ions, the formation of mono and poly-layer of oxides, and the Faraday adsorption of ions such as lead and cadmium to form monolayers of these metals in gold. (Author)