. We interviewed farm managers about their perceptions of wading bird problems and conducted preliminary surveys of wading bird populations at 67 randomly selected channel catfish Ictalurus punctatus pond complexes in northwest Mississippi during December 1995. At a subsample of 24 complexes and 10 other complexes previously surveyed in 1990, we surveyed wading bird populations bimonthly throughout the year in 1996 and observed great blue herons Ardea herodias and great egrets Ardea alba feeding at catfish ponds. Seventy‐five percent of farm managers questioned felt that wading birds were causing losses to their fish stocks, and 74% believed the problem was increasing. Consistent with interview results, 88% of the pond complexes surveyed had one or more wading birds present. Despite reported harassment programs by producers, great blue heron densities at 10 complexes previously surveyed in 1990 had increased by more than eightfold in 1996. Great blue heron densities varied with location, season and time of day, but the average 127‐ha farm supported about 78 herons and 56 great egrets. Despite similar populations, the potential impact of these two species was quite different. Live catfish, averaging 10.3 cm in length (circa 10 g) comprised only 8% of the egret diet by weight, and most of the fish were obtained from fingerling ponds during periods when these fingerlings may be weakened by the bacterial disease, enteric septicemia of catfish. In contrast, live catfish, averaging 16 cm in length (circa 34 g), comprised 44% of the great blue heron diet by weight. Herons foraged from both fingerling and food fish ponds, primarily in the early morning and evening. Based on average population densities and foraging rates, herons at the average 127‐ha farm in northwest Mississippi consumed 114,000 (circa 3,900 kg) catfish, annually. However, further studies are recommended to document production losses.

Studies of the annealing behavior of (100) silicon wafers in argon in the temperature interval 900~176 indicate that "thermal etching" of silicon is not due to either evaporation of silicon, or reaction with gas-phase contaminant species, as has been proposed. Instead, it appears due to the reaction of silicon with the fused silica wafer carrier, the silica creeping over the wafer surface, and reacting with it. In a series of vertically stacked wafers arrayed perpendicularly to the gas stream flow direction, the furthermost upstream wafer exhibits the greatest degree of thermal etching because the surrounding gas contains the smallest concentration of SiO. The latter is present as a consequence of the reaction between Si and SIO2. The furthermost downstream wafer exhibits the least amount of thermal etching, because the gas surrounding it has become saturated with SiO during its passage over the wafer array. The increased gas-phase concentration of SiO retards further reaction of the downstream wafers with the fused silica wafer carrier. The thermal etching behavior is highly anisotropic at 1000~ becoming much less so at 1100~ and above. In a SiC carrier, the thermal etching is reduced dramatically.

Continental Upper Triassic Yanchang “black shales” in the southeastern Ordos Basin have been proven to be unconventional gas reservoirs. Organic-matter-lean and organic-matter-rich argillaceous mudstones form reservoirs that were deposited in a deeper water lacustrine setting during lake highstands. In the stratified lake, the bottom waters were dysaerobic to anoxic. This low-energy and low-oxygen lake-bottom setting allowed types II and III organic matter to accumulate. Interbedded with the argillaceous mudstones are argillaceous arkosic siltstones deposited by gravity-flow processes. Rock samples from the Yanchang Chang 7–9 members are very immature mineralogically. Mineral grains are predominantly composed of relatively equal portions of quartz and feldspar. The high clay-mineral content, generally greater than 40%, has promoted extensive compaction of the sediments, permitting the ductile material to deform and occlude interparticle pores. Furthermore, this high clay-mineral content does not favor hydraulic fracturing of the mudstone reservoir. The pore network within the mudstones is dominated by intraparticle pores and a lesser abundance of organic-matter pores. Interparticle pores are rare. The mean Gas Research Institute (GRI) crushed-rock porosity is 4.2%. Because the pore network is dominated by poorly connected intraparticle pores, permeability is very low (the GRI-calculated geometric mean permeability = 9.9 nd). The dominance of intraparticle pores creates a very poor correlation between GRI porosity and GRI permeability. Several methods of porosity analysis (GRI crushed rock, nitrogen adsorption, and point count) were conducted on each samples, and the results were compared. There is no significant correlation between the three methods, implying that each method measures different pore sizes or types. There is also no relationship between the porosity and permeability and total organic carbon. Much of the mature (peak oil window) organic matter is nonporous, suggesting that it is of type III. Most of the organic-matter pores are in migrated solid bitumen. Overall, the samples analyzed have low porosity and permeability for mudrocks.

The use of a Si-based resist system and Ti electrode for the fabrication of sub-10 nm metal-insulator-metal tunnel junctions Ti SI atoms diffuss to metal lay". to ferm sHOeld" FIG. 3, Model for silicon vaClIllCY injection during the formation of TiSi 2 .

Using coevaporated Ti-Co alloy and sequentially evaporated Ti-Co bimetallic layer source materials, CoSi2 films have been grown on (001) Si. The film resistivity and resistance thermal stability are excellent. The CoSi2 are epitaxial single-crystal films containing antiphase domains in the Ti-Co bimetallic layer cases and are polycrystalline films containing a substantial portion of epitaxial grains in the Ti-Co alloy cases. The epitaxial or substantially epitaxial nature of these CoSi2 films is the reason for the excellence in the film resistivity and resistance thermal stability. We believe that the epitaxial nature of the CoSi2 films results from two roles played by Ti. In the first, Ti served as a getterer for removing the native oxide layer on the Si wafer surfaces, which causes the nucleation of CoSi2 grains with random orientations. In the second, Ti silicides formed in the early stage of the annealing process served as Co diffusion barriers preventing Co2Si and CoSi formation, which would also lead to the formation of randomly oriented CoSi2 grains. Models of the interfacial structure of the epitaxial CoSi2 film and Si substrate have been constructed for [001] and [111] orientations. These models revealed that antiphase boundaries serve the role of relieving the lattice mismatch between the epitaxial CoSi2 film and Si substrate.

Previous research has explored how the content of landscape photography (i.e., natural vs. human-made) and postmanipulation of photographs (e.g., clarity and color) can influence aesthetic judgments. Although natural landscapes are reliably rated as more likable compared with human-made landscapes, very little is known about combined natural and human-made landscapes that depict alterations of the natural world by human interventions. After categorizing the works of Edward Burtynsky as “combined” landscapes along a continuum between natural and human-made landscape photographs, participants rated the likability and familiarity (i.e., whether landscapes were previously viewed or not) of all three types of images in a series of three experiments that measured likability and familiarity differences as a function of landscape type (Experiment 1), postmanipulation of color (Experiment 2), and postmanipulation of image clarity (Experiment 3). Natural photographs were rated significantly higher than all other photograph types (regardless of color or clarity manipulation), and combined photographs were significantly rated the lowest in all experimental conditions, especially those that were previously viewed. Across all conditions, previously viewed photographs were reliably discriminated from those that were not. The results suggest that the combined Burtynsky photographs fall outside a continuum of likability between natural and human-made extremes, and such a low aesthetic rating of previously viewed combined photographs may be because of negative social priming, an altered fluency processing, or both.

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The stability of thin interfacial oxide layers between bonded silicon wafers is investigated experimentally and theoretically. For usual bonding temperatures around 1100 °C and typical times of a few hours, the oxygen diffusivity is not high enough to allow the oxide layer dissolution. For aligned wafers of the same orientation, the oxide layer instead tends to disintegrate in order to minimize the SiO2/Si interface energy. It is possible to stabilize a uniform interfacial oxide layer by rotationally misorienting the two wafers by an angle θ exceeding a critical angle, θ crit, estimated to be between 1° and 5°.