Fabrication of Sub‐10 nm Metallic Lines of Low Line‐Width Roughness by Hydrogen Reduction of Patterned Metal–Organic Materials

The fabrication of very narrow metal lines by the lift‐off technique, especially below sub‐10 nm, is challenging due to thinner resist requirements in order to achieve the lithographic resolution. At such small length scales, when the grain size becomes comparable with the line‐width, the built‐in stress in the metal film can cause a break to occur at a grain boundary. Moreover, the line‐width roughness (LWR) from the patterned resist can result in deposited metal lines with a very high LWR, leading to an adverse change in device characteristics. Here a new approach that is not based on the lift‐off technique but rather on low temperature hydrogen reduction of electron‐beam patterned metal naphthenates is demonstrated. This not only enables the fabrication of sub‐10 nm metal lines of good integrity, but also of low LWR, below the limit of 3.2 nm discussed in the International Technology Roadmap for Semiconductors. Using this method, sub‐10 nm nickel wires are obtained by reducing patterned nickel naphthenate lines in a hydrogen‐rich atmosphere at 500 °C for 1 h. The LWR (i.e., 3 σ_LWR) of these nickel nanolines was found to be 2.9 nm. The technique is general and is likely to be suitable for fabrication of nanostructures of most commonly used metals (and their alloys), such as iron, cobalt, nickel, copper, tungsten, molybdenum, and so on, from their respective metal–organic compounds.     

Microstructure,mechanical properties,and corrosion resistance of Ti-20Zr alloy in undoped and NaF doped artificial saliva

The corrosion behavior of a new, advanced Ti-20Zr alloy with α+β microstructure (determined by optical microscopy, XRD, and SEM) and very good mechanical properties (obtained from the stress-strain curve) is studied in this paper. The composition of the alloy native passive film was determined from a XPS analysis and the long-term corrosion resistance in undoped and doped states with 0.05M NaF artificial Carter-Brugirard saliva of different pH values, simulating the severe functional conditions of a dental implant, was analyzed by electrochemical methods. This alloy possesses an advantageous balance between good mechanical resistance and plasticity and Young’s modulus and exhibits more favorable electrochemical parameters and corrosion resistance than CP Ti due to its more resistant passive layer containing Ti₂O₃, TiO₂, and ZrO₂ protective oxides. After 1000 h of immersion in saliva, the protective properties of the alloy were enhanced due to the deposited surface layer that incorporated protective phosphates (shown by SEM and XPS).     

Antioxidant activity prediction and classification of some teas using artificial neural networks

In order to characterise and to classify some teas a simple, rapid and economical method based on composition, antioxidant activity and artificial neural networks (ANNs) is proposed. For these purpose two types of ANN based applications have been developed: one for predicting the antioxidant activity and a second one for establishing the class of the teas. The complex relationship between the total antioxidant activity (AA) depending on the total flavonoids content (F), total catechins content (C) and total methyl-xanthines content (MX) of commercial teas was revealed by the first designed feed-forward ANN. Secondly, using a probabilistic ANN, successful tea classification in various classes (green tea, black tea and express black tea) was also performed.     

Upper eyelid orbicularis oculi flap with tarsoconjunctival island for reconstruction of full-thickness lower lid defects

BACKGROUND: Various cryopreservation techniques have been investigated to elongate preservation time, however, most have failed to be clinically induced because of damage due to ice crystal formation. Subzero nonfreezing conditions could theoretically reduce organ metabolism without damage due to ice crystal formation. We evaluated the superiority of subzero nonfreezing storage compared with conventional hypothermic storage using isolated rat hepatocytes stored in University of Wisconsin (UW) solution without cryoprotectants. METHODS: Hepatocytes of Wistar rats isolated by collagenase digestion were suspended in UW solution and divided into the following three groups: subzero nonfreezing group (-4 degrees C), zero nonfreezing group (0 degrees C), and control group (4 degrees C). They were stored for 48 hr at the temperatures indicated. After 24 and 48 hr of storage, we carried out a trypan blue exclusion test and a 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, and measured lactate dehydrogenase release, lactic acid, ATP content, and the ability of hepatocytes to synthesize urea. After 48 hr of storage, morphological differences between the control group and the subzero nonfreezing group were investigated by scanning and transmission electron microscopy. RESULTS: Significant improvements of the trypan blue exclusion test and ATP contents in the subzero nonfreezing group were observed. Lactic acid production was also significantly suppressed in the subzero nonfreezing group compared with that in the control group. The MTT assay value was significantly better at -4 degrees C than at 4 degrees C. The rate of urea synthesis at -4 degrees C was higher than that at 4 degrees C. Electron microscopy revealed that subzero nonfreezing delayed the lethal bleb-forming process of stored hepatocytes, which was followed by mitochondrial swelling, compared with the control group. CONCLUSIONS: Subzero nonfreezing storage (-4 degrees C) in UW solution could provide better preservability for isolated rat hepatocytes with protection against hypoxic cell injury compared with conventional hypothermic storage (4 degrees C).     

Lanthanum cobaltite nanoparticles using the polymeric precursor method

The present study reports the evolution of reactive lanthanum cobaltite nanoparticles obtained by a polymeric precursor route, using citric acid as chelating agent. The crystallization from amorphous precursor, particle growth and the formation of nanoparticle agglomerates at different calcination temperatures was carried out by conventional and high-resolution electron microscopy, electron diffraction and energy-dispersive X-ray analysis and Raman spectroscopy. Microstructure measurements were compared with X-ray diffraction and chemical analysis results. Electron diffraction, combined with TEM, was used to determine the proportion of amorphous phase. The presence of amorphous carbon during the decomposition of the amorphous precursor was analyzed by Raman spectroscopy. The coherent crystalline domain size and the particle size have been monitored by XRD and electron microscopy in order to determine the evolution of both crystal size and the temperature onset for the formation of polycrystalline aggregates.The results demonstrate that at 550 °C we obtain pure single-phase equiaxed nanopowders of LaCoO₃ with crystal size of 20 nm, free of amorphous carbon and without the presence of polycrystalline aggregates.     

The influence of neutron irradiation on (B0.65C0.35)Ba1.4Sr0.6Ca2Cu3Oz superconducting phase: The role of the grain edge

Using the transport and magnetization measurements, the influence of neutron irradiation at a fluence of 5 × 10¹⁷ n cm⁻² on (B_0.65C_0.35)Ba_1.4Sr_0.6Ca₂Cu₃O _z has been investigated. The neutron irradiation was found to decrease critical temperature and transport critical current density, increase the residual and normal state resistivity, and improve the intragranular critical current density with 1.6 × 10⁵ A/cm² (at 77.3 K and in the applied field up to 160 kA m) and ΔM _irr/ΔM _nonirr ratio (up to factor of 3) at highest field used for investigation. The field dependence of this ratio, which is below the unity at very low field but higher than 1 at high fields, correlated with the shape of the hysteretic loops as well as with the change of the transport parameters after irradiation suggests the role of the irradiation-induced effects on the grain edges. We discuss these effects in the framework of the Bean-Livingstone surface barriers and geometrical barriers.