Efficient electron transport in 4,4′-bis[N-(1-napthyl)-N-phenyl-amino] biphenyl and the applications in white organic light emitting devices

The electron transport capability of 4,4′-bis[N-(1-napthyl)-N-phenyl-amino] biphenyl (α-NPD) was investigated by fundamental physical measurements named as current–voltage (I–V) electrical property evaluation and displacement current measurement (DCM). In electron-dominated devices, the I–V characteristics of α-NPD were similar as that of (8-hydroxyquinolino) aluminum (Alq₃) owing to their same order of electron mobilities. The interface of Al/LiF and α-NPD was proven to be an Ohmic contact through the evaluation of I–V characteristics at low bias regime (<3 V). And an electron injection barrier, 0.21 eV, at Al/LiF/α-NPD was obtained by extrapolating the temperature dependent I–V curves. The electron transport behavior in α-NPD film was further confirmed by DCM evaluations. Furthermore, an efficient white organic light emission device was successfully fabricated by using α-NPD as hole transport layer and electron transport layer, respectively.     

Acute illness induces the release of aversive odor cues from adult, but not prepubertal, male rats and suppresses social investigation by conspecifics.

The present study examined odorant communication during acute illness provoked by injection of lipopolysaccharide (LPS; 100 μg/kg) and how these effects vary between prepubertal and adult conspecifics. Exposure to odor of LPS-treated adult male rats produced increased avoidance in both sexes of adults and prepubertal male partners. This response was not found when they were exposed to odor of LPS-treated prepubertal males. Even a 2.5-fold higher load of LPS in prepubertal males failed to produce aversive odor cues, suggesting that the difference in the odor is not a simple issue of dose/body volume. Both estradiol benzoate (20 μg/kg) and testosterone propionate (500 μg/kg), but not dihydrotestosterone (500 μg/kg) pretreatment in prepubertal males administered LPS restored the expression of aversive odor. These hormone treatments per se did not influence odor properties of prepubertal males, indicating that estrogen receptors may play a key regulatory role in the expression of aversive odor in LPS-treated prepubertal rats. These data suggest that the expression of sickness-related odor emerges through puberty, and likely involves a complex interaction between inflammation and sex steroids across development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Sampling Tube Geometry on Soft Clayey Sample Quality Evaluated by Nondestructive Methods

Sample disturbance caused by difference in sampling tube geometry was evaluated by two nondestructive methods: the measurement of the residual effective stress (p_r') by ceramic disc; and the use of the bender element to ascertain the shear wave velocity (V_s), and thus the maximum shear modulus (G_BE). Samples were measured under atmosphere, i.e., not under confined stress conditions. The soil samples were obtained from two sources: reconstituted Kasaoka clay prepared in the laboratory, and at the test site at Takuhoku, Hokkaido, Japan. Samplers with different geometrical designs, referring to the Japanese standard stationary piston sampler, were used for the model ground and field sampling. The geometrical effects of the sampling tube, for example, the thickness of the tube wall, the edge angle, and the existence of a piston were carefully examined. The quality of the samples taken with different samplers was evaluated by p_r' and G_BE, values which were normalized by the in situ vertical effective stress (σ'_vo) and G_f measured by the seismic cone test in the field. It was found from these studies that p_r'/σ'_vo and G_BE/G_f vary considerably due to the geometry of the sampler, with the edge angle of sampling tubes being the most important feature in obtaining high quality samples. The wall thickness, and thus, the area ratio of the sampler is not critical to the sample quality if the edge angle is sharp enough. The existence of the piston does not significantly influence the sample quality in field samples. Furthermore, the correlation between G_BE and p_r' was also investigated, and it was found that the two parameters are strongly dependent.     

Influence of a fiber-network microstructure of paper-structured catalyst on methanol reforming behavior

A novel microstructured catalyst that consists of Cu/ZnO catalyst powders and ceramic fibers was successfully prepared using pulp fibers as a tentative matrix by a papermaking technique. As-prepared material, called a paper-structured catalyst, possessed porous microstructure with layered ceramic fiber networks (average pore size ca. 20 μm, porosity ca. 50%). In the process of methanol autothermal reforming (ATR) to produce hydrogen, paper-structured catalysts demonstrated both high methanol conversion and low concentration of undesirable carbon monoxide as compared with catalyst powders and pellets. The catalytic performance of paper-structured catalysts depended on the use of pulp fibers, which were added in the paper-forming process and finally removed by thermal treatment before ATR performance tests. Confocal laser scanning microscopy and mercury intrusion analysis suggested that the tentative pulp fiber matrix played a significant role in regulating the fiber-network microstructure inside paper composites. Various metallic filters with different average pore sizes, used as supports for Cu/ZnO catalysts, were subjected to ATR performance tests for elucidating the pore effects. The tests indicated that the pore sizes of catalyst support had critical effects on the catalytic efficiency: the maximum hydrogen production was achieved by metallic filters with an average pore size of 20 μm. These results suggested that the paper-specific microstructures contributed to form a suitable catalytic reaction environment, possibly by promoting efficient diffusion of heat and reactants. The paper-structured catalyst with a regular pore microstructure is expected to be a promising catalytic material to provide both practical utility and high efficiency in the catalytic gas-reforming process.     

Effect of static magnetic field on a thermal conductivity measurement of a molten droplet using an electromagnetic levitation technique

Recently, a novel method of measuring the thermophysical properties, particularly thermal conductivity, of high-temperature molten materials using the electromagnetic levitation technique has been developed by Kobatake et al. [H. Kobatake, H. Fukuyama, I. Minato, T. Tsukada, S. Awaji, Noncontact measurement of thermal conductivity of liquid silicon in a static magnetic field, Appl. Phys. Lett. 90 (2007) 094102]; this method is based on a periodic laser-heating method, and entails the superimposing of a static magnetic field to suppress convection in an electromagnetically levitated droplet. In this work, to confirm the fact that a static magnetic field really suppresses convection in a molten silicon droplet in an electromagnetic levitator, numerical simulations of convection in the droplet and periodic laser heating in the presence of convection have been carried out. Here, the convections driven by buoyancy force, thermocapillary force due to the temperature dependence of the surface tension on the melt surface, and electromagnetic force in the droplet were considered. As a result, it was found that applying a static magnetic field of 4 T can suppress convection in a molten silicon droplet enough to measure the real thermal conductivity of molten silicon.     

Mercury oxidation by hydrochloric acid over TiO2 supported metal oxide catalysts in coal combustion flue gas

Mercury oxidation by hydrochloric acid over the metal oxides supported by anatase type TiO₂ catalysts, 1 wt.% MO_x/TiO₂ where M = V, Cr, Mn, Fe, Ni, Cu, and Mo, was investigated by the Hg⁰ oxidation and the NO reduction measurements both in the presence and absence of NH₃. The catalysts were characterized by BET surface area measurement and Raman spectroscopy. The metal oxides added to the catalyst were observed to disperse well on the TiO₂ surface. For all catalysts studied, the Hg⁰ oxidation by hydrochloric acid was confirmed to proceed. The activity of the catalysts was found to follow the trend MoO₃ ~ V₂O₅ > Cr₂O₃ > Mn₂O₃ > Fe₂O₃ > CuO > NiO. The Hg⁰ oxidation activity of all catalysts was depressed considerably by adding NH₃ to the reactant stream. This suggests that the metal oxide catalysts undergo the inhibition effect by NH₃. The activity trend of the Hg⁰ oxidation in the presence of NH₃ was different from that observed in its absence. A good correlation was found between the NO reduction and the Hg⁰ oxidation activities in the NH₃ present condition. The catalyst having high NO reduction activity such as V₂O₅/TiO₂ showed high Hg⁰ oxidation activity. The result obtained in this study suggests that the oxidation of Hg⁰ proceeds through the reaction mechanism, in which HCl competes for the active catalyst sites against NH₃. NH₃ adsorption may predominate over the adsorption of HCl in the presence of NH₃.     

Deposition of DLC film with adhesive W-DLC layer on stainless steel and its tribological properties

Tribological properties of a diamond-like carbon (DLC) coating with an adhesive tungsten-containing DLC (W-DLC) layer were investigated. The coatings were deposited onto AISI316L steel substrates and Si wafers using plasma enhanced chemical vapor deposition and tungsten co-sputtering of the metal target. Methane and argon gases were used as the precursor of the coatings. In this study, three types of coatings were evaluated: DLC/W-DLC on AISI316L (DLC-1), DLC/W-DLC on Si wafer (DLC-2), and DLC on Si wafer (DLC-3). The structural characterizations were performed by transmission electron microscopy and tapping mode atomic force microscopy. At the boundary between the W-DLC layer and the AISI316L substrate, microscopic decohesion or delamination was not observed. The surface roughness of the DLC-1 coating was greater than that of the DLC-2 coating. This feature was derived from the surface roughness of the initial surface of the AISI316L substrate. Friction tests were performed using a rotation-type ball-on-flat configuration tribometer. The observed friction of the DLC-1 coating was unstable compared with the DLC-2 or DLC-3 coatings. This was due to wear debris which had risen to the friction surface resulting in unstable friction on the DLC-1 coating. During the friction studies, the top DLC layer was removed from the adhesive W-DLC layer because the adhesive strength at this part was not enough. In order to achieve the low and stable friction of the DLC coating with the W-DLC layer on AISI316L, it is necessary to improve the smoothness of the surface and the adhesion between the DLC coating and the W-DLC layer.     

A 65 nm Single-Chip Application and Dual-Mode Baseband Processor With Partial Clock Activation and IP-MMU

Supporting both WCDMA with HSDPA and GSM/GPRS/EDGE, the 9.3 times 9.3 mm² SoC fabricated in triple-Vth 65 nm CMOS, has three CPU cores and 20 separate power domains. Unused power domains can be powered down to reduce the leakage power. Partial clock activation scheme especially focused on music playback scene dynamically stops a PLL and clock trees when not necessary and reduces power consumption from 33.6 mW to 19.6 mW. IP-MMU translates virtual address to physical address for 18 hardware-IPs and virtual address space can be allocated when necessary and can be freed after its operation, reducing external memory by 43 MB. Video performance of D1 (720 times 520) size with 30 frames per second for MPEG/AVC decoding and encoding can be achieved under mixed virtual and physical address usage.