Effect of field-annealing on magnetostriction and tunneling magnetoresistance of Co/AlOx/Co/IrMn junctions

The magnetostriction (λ_s) and tunneling magnetoresistance (TMR) of two Co/AlO_x/Co/IrMn MTJ systems that were deposited on Si(1 0 0) and glass substrate were examined at RT and field-annealing with various thicknesses of AlO_x. One structure was a Si(1 0 0)/Ta/Co/AlO_x/Co/IrMn/Ta system, and the other was a glass/Co/AlO_x/Co/IrMn system. The experimental results reveal that, in the Si(1 0 0)/Ta/Co/AlO_x/Co/IrMn/Ta system, the ratio of TMR is maximal under the field-annealing condition, and is optimal at an AlO_x thickness of 26 Å as well as in the RT condition. EDS analysis demonstrates that, these results are related to the distribution of Co and O atoms, because the oxidation of AlO_x is most extensive at a thickness of 26 Å. In the glass/Co/AlO_x/Co/IrMn system, λ_s does not significantly vary under the RT condition; however, λ_s is maximized (?20 ppm) by field-annealing at an AlO_x thickness of 17 Å. The abundance of Co and O in the system dominates the behavior of λ_s, according to EDS analysis. Finally, the minimum value of λ_s and the maximum ratio of TMR are ?8 ppm and 60%, respectively, at an AlO_x thickness of 26 Å under the field-annealing condition.     

CFD simulation and assessment of life safety in a subway train fire

Fire is a major risk in the event of subway train fire due to coincidence with direction of smoke flow and evacuation. As a part of an effort to improve the life safety in a train fire, the platform screen door (PSD) is more and more installed on the ground that PSD provides a lot of benefits to passenger’s safety. Therefore, the investigation of effect of PSD on life safety is needed. In this study, fire simulation and evacuation simulation are performed to estimate the effect of PSD and ventilation on passenger’s life safety in a subway train fire. The Fire Dynamics Simulator (FDS V406) code is used to predict smoke spread and the available safe egress time during the fire. The evacuation of a subway station due to a train fire is simulated to predict the time required for evacuation, obtaining travel speed as a function of density. The passengers in platform with PSD and ventilation system have much more available time of about 350 s than passengers in case without PSD and ventilation system in modeled subway station. The subway turnstiles (ticket gate) dramatically increase the time required for evacuation without moving toward exits and bring passenger’s life safety danger in a subway train fire.     

Considerations on direct stream flow measurements using video imagery: Outlook and research needs

The paper presents measurements acquired with Large-Scale Particle Image Velocimetry (LSPIV) during normal flows and floods in the Iowa River (U.S.A). For normal flows, comparison is made with measurements obtained with Acoustic Doppler Current Profilers (ADCP) in order to test LSPIV’s performance and to address concerns potentially affecting the accuracy of the measurements. The historic flood of the Iowa River during the summer of 2008 was captured for testing LSPIV capabilities during extreme flows. Lacking alternative measurements during the flood, the LSPIV measurements are compared to the rating curve extrapolated for high flows using a one-to-one discharge–stage relationship. The comparison reveals limitations of the single-values rating curve for providing discharge estimates during high flows. Finally, the paper summarizes lessons learned during these and previous LSPIV studies with the intent to chart the research needed to enhance this promising non-intrusive field measurement technique.     

Microorganism identification by mass spectrometry and protein database searches.

A method for rapid identification of microorganisms is presented, which exploits the wealth of information contained in prokaryotic genome and protein sequence databases. The method is based on determining the masses of a set of ions by MALDI TOF mass spectrometry of intact or treated cells. Subsequent correlation of each ion in the set to a protein, along with the organismic source of the protein, is performed by searching an Internet-accessible protein database. Convoluting the lists for all ions and ranking the organisms corresponding to matched ions results in the identification of the microorganism. The method has been successfully demonstrated on B. subtilis and E. coli, two organisms with completely sequenced genomes. The method has been also tested for identification from mass spectra of mixtures of microorganisms, from spectra of an organism at different growth stages, and from spectra originating at other laboratories. Experimental factors such as MALDI matrix preparation, spectral reproducibility, contaminants, mass range, and measurement accuracy on the database search procedure are addressed too. The proposed method has several advantages over other MS methods for microorganism identification.     

Effect of the reaction bath temperature in a fixed-bed reactor for oxidation of oxylene over V2O5/TiO2 catalysts

The effects of the reaction variables in the operation of a fixed-bed reactor for oxidation ofo-xylene over V₂O₅/TiO₂ catalysts were studied experimentally using a bench reactor. Reaction temperature, feed flow rate and feed concentration ofo-xylene were found to have significant effects on the product distribution and the temperature profile in the reactor. Drastic enhancements ofo-xylene oxidation reaction were observed at some conditions, which was ascribed to the effect of heat accumulated in the bed and indicated a possible way to increase the productivity in the industrial condition. This paper was presented at the 8th APCChE (Asia Pacific Confederation of Chemical Engineering) Congress held at Seoul between August 16 and 19, 1999.     

Insights on Ceramics as Dental Materials. Part II: Chemical Surface Treatments

The purpose of surface treatment (conditioning) methods on dental ceramics is to improve the retention and bonding between the enamel or the dentin and ceramic veneer, with the help of resin composite luting cements. These types of surface treatments include chemically altering the surface of ceramics with some specific acidic etchants followed by applying a silane coupling agent (silane). The silane currently used in dentistry is 3-methacryloxypropyltrimethoxysilane, a hybrid organic–inorganic trialkoxy ester monomer, which is diluted in an acidified water-ethanol solvent system. Such silane primers are said to be pre-hydrolyzed. Some oxide ceramics with high crystalline content, such as alumina and zirconia, cannot be easily etched with acid etchants. They should be silica-coated and silanized prior to bonding. A silane coupling agent should be applied after silica-coating to the ceramic surface to achieve chemical bonding and the optimal durable bond strength.     

Redox behavior and electrical properties of Sr and Zr substituted BaTiO3

The oxidation and reduction behavior of Sr and Zr substituted BaTiO₃ has been studied by measuring equilibrium electrical conductivities as a function of oxygen activity. The substitution of Sr⁺² and Zr⁺⁴ for Ba²⁺ and Ti⁴⁺ in BaTiO₃ shifted the conductivity profiles to lower oxygen partial pressures. The replacement of Ba with smaller Sr ions suppresses the oxygen dissociation from the lattice, consequently increasing the enthalpy for reduction (ΔH _n ), whereas the Sr substitution requires less energy for oxidation (ΔH _p ). The increase in reduction enthalpy at lower oxygen activities suppresses the formation of oxygen vacancies, the materials becoming resistant to reduction process. Such a reduction resistant behavior gave rise to greater electrical resistivities for (Ba_0.9Sr_0.1)(Ti_0.9Zr_0.1)O₃ than for Ba(Ti_0.9Zr_0.1)O₃ when the samples were sintered at lower P(O₂).     

Role of mixed hole transport layer with exciton blocking properties in phosphorescent organic light-emitting diodes

Improved efficiency in green phosphorescent organic light-emitting diodes using a composite hole transport layer (HTL) with hole transport and exciton blocking function was investigated. Mixed layer of (4,4′-N,N′-dicarbazole)biphenyl (CBP) and N,N′-di(1-naphthyl)-N,N′-diphenylbenzidine (NPB) was used as a HTL and quantum efficiency could be enhanced from 4.3% to 8.1% at 100 cd/m². Best performances could be obtained in the device with 50% CBP and 50% NPB in the HTL.