In this investigation, YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) films were fabricated via a metal acetate, trifluoroacetic acid based sol-gel route, and spin-coat deposited on (100) LaAlO{sub 3} with a focus on maximizing J{sub c}, while minimizing processing time. We demonstrate that the use of a low pO{sub 2} atmosphere during the pyrolysis stage can lead to at least a tetiold reduction in pyrolysis time, compared to a 1 atm. O{sub 2} ambient. High-quality YBCO films on LaAlO{sub 3}, with J{sub c} values up to 3 MA/cm{sup 2} at 77 K, can be routinely crystallized from these rapidly pyrolyzed films.
The Department of Energy (DOE) is working to accelerate the acceptance and application of innovative technologies that improve the way the nation manages its environmental remediation problems. The DOE Office of Science and Technology established the Accelerated Site Technology Deployment Program (ASTD) to help accelerate the acceptance and implementation of new and innovative soil and ground water remediation technologies. Coordinated by the Department of Energy's Idaho Office, the ASTD Program reduces many of the classic barriers to the deployment of new technologies by involving government, industry, and regulatory agencies in the assessment, implementation, and validation of innovative technologies. Funding is provided through the ASTD Program to assist participating site managers in implementing innovative technologies. The program provides technical assistance to the participating DOE sites by coordinating DOE, industry, and regulatory participation in each project; providing finds for optimizing full-scale operating parameters; coordinating technology performance monitoring; and by developing cost and performance reports on the technology applications.
Atomically flat monolayer and trilayer films of polydiacetylenes have been prepared on mica and silicon using a horizontal deposition technique from a pure water subphase. Langmuir films of 10,12-pentacosadiynoic acid (I) and N-(2-ethanol)-10,12-pentacosadiynamide (II) were compressed to 20 mN/m and subsequently polymerized by UV irradiation at the air-water interface. Blue and red forms of the films were prepared by varying exposure times and incident power. Polymerization to the blue-phase films produced slight contractions of 2 and 5% for the films of II and I, respectively. Longer UV exposures yielded red-phase films with dramatic film contraction of 15 and 32% for II and I, respectively. The horizontal deposition technique provided transfer ratios of unity with minimal film stress or structure modification. Atomic force microscopy images revealed nearly complete coverage of the substrate with atomically flat films. Crystalline domains of up to 100 micrometers of highly oriented polydiacetylene molecules were observed. The results reported herein provide insight into the roles of molecular packing and chain orientations in converting the monomeric film to the polymerized blue and red phases. (C) 2000 Academic Press.
Understanding high pressure behavior materials is necessary in order to address the physical processes associated with hypervelocity impact events related to space science applications including orbital debris impact and impact lethality. Until recently the highest-pressure states in materials have been achieved from impact loading techniques from two-stage light gas guns with velocity limitations of approximately 81cm/s. In this paper, techniques that are being developed and implemented to obtain the needed shock loading parameters (Hugoniot states) for material characterization studies, namely shock velocity and particle velocity, will be described at impact velocities up to 11 kds. The determination of equation-of-state (EOS) and thermodynamic states of materials in the regimes of extreme high pressures is now attainable utilizing the three-stage launcher. What is new in this report is that these techniques are being implemented for use at engagement velocities never before attained utilizing two-stage light-gas gun technology. The design and test methodologies used to determine Hugoniot states are described in this paper.
Sweeping has become the workhorse algorithm for creating conforming hexahedral meshes of complex models. This paper describes progress on the automatic, robust generation of MultiSwept meshes in CUBIT. MultiSweeping extends the class of volumes that may be swept to include those with multiple source and multiple target surfaces. While not yet perfect, CUBIT's MultiSweeping has recently become more reliable, and been extended to assemblies of volumes. Sweep Forging automates the process of making a volume (multi) sweepable: Sweep Verification takes the given source and target surfaces, and automatically classifies curve and vertex types so that sweep layers are well formed and progress from sources to targets.