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Notes: The mechanisms of the formation of titanium silicide from the reaction of a single thin film of Ti on the silicon substrate with different degrees of substrate amorphization were studied using differential scanning calorimetry. With increased amorphization, an exothermic reaction prior to C49-TiSi2 formation was observed. X-ray diffraction discovered an unidentified phase together with Ti5Si3 and Ti5Si4 that disappeared with subsequent formation of C49-TiSi2 at temperatures above 650 °C. The difference in Gibbs free energy was considered in explaining the formation of Ti5Si3 and Ti5Si4. Based on the Scherrer equation, the resultant C49-TiSi2 grains with higher degrees of silicon substrate amorphization were smaller than those without silicon substrate amorphization. © 2002 American Institute of Physics.

Notes: Grain growth and strain release processes in the electrodeposited nanocrystalline (nc) Cu specimen with a high purity were investigated by means of differential scanning calorimetry, x-ray diffraction, electrical resistance measurement, and high-resolution transmission electron microscopy. It was found that for the as-deposited nc Cu, the grain growth started at about 75 °C, at which the microstrain in (111) plane (e111) began to release, while the mean microstrain and that in (100) plane (e100) began to release at a higher temperature (150 °C). With an increment in microstrain in the nc Cu introduced by cold rolling, the grain growth onset temperature increased while the strain release onset temperature dropped obviously. These results showed an evident correlation between the grain size stability and the microstrain in the nc materials. The activation energy for the grain growth was determined by using Kissinger analysis and isothermal kinetics analysis, being about 86 kJ/mol, implying that the grain growth process is dominated by grain boundary diffusion. © 2001 American Institute of Physics.

Notes: The Fuping Complex and the adjoining Wutai and Hengshan Complexes are located in the central zone of the North China craton. The dominant rock types in the Fuping Complex are high-grade tonalitic–trondhjemitic–granodioritic (TTG) gneisses, with minor amounts of mafic granulites, syntectonic granitic rocks and supracrustal rocks. The petrological evidence from the mafic granulites indicates three stages of metamorphic evolution. The M1 stage is represented by garnet porphyroblasts and matrix plagioclase, quartz, orthopyroxene, clinopyroxene and hornblende. Orthopyroxene+plagioclase symplectites and clinopyroxene+plagioclase±orthopyroxene coronas formed in response to decompression during M2 following the peak metamorphism at M1. Hornblende+plagioclase symplectites formed as a result of further isobaric cooling and retrograde metamorphism during M3. The P–T  estimates using TWQ thermobarometry are: 900–950 °C and 8.0–8.5 kbar for the peak assemblage (M1), based on the core compositions of garnet, matrix pyroxene and plagioclase; 700–800 °C and 6.0–7.0 kbar for the pyroxene+plagioclase symplectites or coronas (M2); and 550–650 °C and 5.3–6.3 kbar for the hornblende+plagioclase symplectites (M3), based on garnet rim and corresponding symplectic mineral compositions. These P–T  estimates define a clockwise P–T  path involving near-isothermal decompression for the Fuping Complex, similar to the P–T  path estimated for the metapelitic gneisses. The inferred P–T  path suggests that the Fuping Complex underwent initial crustal thickening, subsequent exhumation, and finally cooling and retrogression. This tectonothermal path is similar to P–T  paths inferred for the Wutai and Hengshan Complexes and other tectonic units in the central zone of the North China craton, but different from anti-clockwise P–T paths estimated for the basement rocks in the eastern and western zones of the craton. Based on lithological, structural, metamorphic and geochronological data, the eastern and western zones of the craton are considered to represent two different Archean to Paleoproterozoic continental blocks that amalgamated along the central zone at the end of Paleoproterozoic. The P–T paths of the Fuping Complex and other tectonic units in the central zone record the collision between the eastern and western zones that led to the final assembly of the North China craton at c. 1800 Ma.

Notes: Introduction:  Hyaluronic acid (HA) is a major glycosaminoglycan component of normal dermis and a major component of the matrix synthesized during wound healing. Previous studies have shown that uncrosslinked HA is rapidly degraded and cleared in vivo, limiting its clinical utility. We have used a novel HA hydrogel scaffold that is crosslinked for prolonged bioavailability. It has a porous interior and a smooth surface. This scaffold can also be fabricated with collagen and linked to proteins or DNA to direct cell growth and differentiation. We hypothesized that this novel HA formulation might itself improve wound healing by enhancing cell migration.Purpose:  The present study explored the effects of a crosslinked HA hydrogel on wound healing.Methods:  Using an established model of wound healing, four 7 mm punch wounds were made on each ear of New Zealand rabbits. Each wound was immediately treated with topical application of one of the following: HA hydrogel (n = 26), HA/collagen hydrogel (n = 27), or phosphate-buffered saline (PBS)(n = 16). Wounds were harvested on day 8 for histologic evaluation. Sections were examined for epithelial and granulation tissue ingrowth into wounds.Results:  HA- and HA/collagen-treated wounds showed statistically significant increases in epithelial (p = 0.003 and p = 0.007, respectively) and granulation tissue ingrowth (p = 0.004 and p = 0.01, respectively) when compared to PBS-treated controls.Conclusions:  In the rabbit ear ulcer model, the application of crosslinked HA and HA/collagen hydrogels accelerated wound healing as measured by epithelial and granulation tissue ingrowth.Funding Source: NIH grant: 5R01GM063825–03

Notes: Claerbout's method has been implemented for the migration of stacked seismic data. A simplified description of the method is given together with an account of some of the practical programming problems and the types of inaccuracy encountered. Routine production results are considered to be comparable or superior to the results derived from alternative migration techniques. Particular advantages are 1) the possibility of using a detailed velocity model for the migration and 2) the preservation of the amplitude and character of the seismic events on the migrated time section.

Notes: The preparation and properties of Cd-diffused p-n homojunction InGaAsP photodiodes designed specifically for operation at the 1.3-μm wavelength are described. At a reverse bias of 10 V, the dark current of these diodes was as low as 15 pA. The peak responsivity at 1.3-μm wavelength was 0.7 A/W. An impulse response (full width at half maximum) of 60 ps and a 3-dB bandwidth of 5.5 GHz were achieved.

Notes: A resonant electron irradiation-induced deep level SE0 in GaAs layers has been investigated by using 50–50 A(ring) uniformly Si-doped GaAs-Ga0.7Al0.3As superlattices and characterized by deep level transient spectroscopy. The formation of a miniband in superlattices changes the forbidden band gap and allows some resonant defects in bulk materials such as SE0 in GaAs to be detected. In these superlattices, three electron irradiation induced deep levels SE0, SE1, and SE2 located in GaAs layers have been observed. In bulk GaAs only two levels, E1 and E2, corresponding to SE1 and SE2 can be detected, since SE0 is a resonant level in bulk GaAs, situated 60 meV above the GaAs conduction band edge. © 1995 American Institute of Physics.

Notes: Using deep level transient spectroscopy (DLTS) the conduction-subband energy levels in a V-shaped potential well induced by Si-δ doping in GaAs were determined. Self-consistent calculation gives four subbands in the well below the Fermi level. Experimentally, two DLTS peaks due to electron emission from these subbands were observed. Another two subbands with low electron concentration are believed to be merged into the adjacent DLTS peak. A good agreement between self-consistent calculation and experiment was obtained. © 1994 American Institute of Physics.

Notes: We have directly measured the Young's modulus and tensile strength of multiwall carbon nanotubes by pulling very long (∼2 mm) aligned nanotube ropes with a specially designed stress-strain puller. This puller can apply an axial force to the rope and simultaneously measure the corresponding rope elongation and the change in rope resistance. The average Young's modulus and tensile strength obtained were 0.45±0.23 TPa and 1.72±0.64 GPa, respectively, which are lower than those calculated and measured previously. The factors that affect the mechanical strengths of nanotubes are discussed. © 1999 American Institute of Physics.