SEARCH · Search NASA
Results for “surface structure”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Superconducting density of states and band structure at the surface of the candidate topological superconductor Au 2 Pb
Not Available
Synthesis, Characterization, Crystal Structure, and Hirshfeld Surface Analysis of Ethyl 2-(4-bromophenyl)-1-cyclohexyl-1H-benzo[d]imidazole-5-carboxylate
The title compound, C{sub 22}H{sub 23}N{sub 2}BrO{sub 2} was synthesized via one-pot reductive cyclization method and characterized by CNH analysis, FT-IR, UV-visible, mass, {sup 1}H and {sup 13}C NMR spectra, thermogravimetric analysis (TGA) and single crystal X-ray diffraction method. The compound crystallizes in monoclinic crystal system: sp. gr. P2{sub 1}/c, Z = 4. The crystal data reveals that the intermolecular interactions of the C–H···π and π···π type connect the molecules which was also visualized with the help of Hirshfeld surface analysis.
Protective structures on the surface of zirconium components of light water reactor cores: Formation, testing, and prototype equipment
The results of tests of plasma treatment of zirconium and deposition of protective yttrium coatings used as the methods of protection of zirconium components of light water reactor cores against hydrogenation are detailed. The amount of hydrogen in the treated sample exposed to superheated steam for 2500 h at temperature T = 400°C and pressure p = 1 atm was five times lower than the corresponding value for the untreated one. The amount of hydrogen in the sample coated with yttrium remained almost unchanged in 4000 h of exposure. A plasma method for rapid testing for hydrogen resistance is proposed. The hydrogenation rate provided by this method is 700 times higher than that in tests with superheated steam. The results of preliminary experiments confirm the possibility of constructing a unit for batch processing of the surfaces of fuel rod claddings.
Dynamic Spatial and Temporal Structures on the Surface of Solids under Load
A model and a method are proposed to explain the origin and main specific features of the dynamic patterns of different types, which were previously observed on the free surface of solids under load in experiments. It is shown that the pattern is formed due to the dynamic instability of the flat surface of the solid under load. This instability develops at the relaxation mechanism caused by the dynamic atomic displacements due to a change in the interatomic interaction during the electron-density redistribution.
Role of oligomer structures in the surface chemistry of amidinate metal complexes used for atomic layer deposition of thin films
The beginning steps of the thermal chemistry of Cu(I)-2-(tert-butylimino)-5,5-dimethyl-pyrrolidinate on metal surfaces were characterized using temperature-programmed desorption experiments and density functional theory (DFT). The relative stability of the initial dimer relative to its dissociation on metal surfaces was evaluated. Several molecular desorption temperatures were identified on Ni(110), but all correspond to dimers, either containing the initial Cu ions or after their removal; no monomer was ever detected. DFT calculations also indicated preferential bonding on Cu(110) as a dimer, albeit with a distorted configuration, via the Cu atoms and in registry with the lattice of the substrate. Furthermore, a potential dissociation pathway of the adsorbed dimer was identified involving the partial detachment of the ligands via the scission of one Cu–N bond at the time and migration to adjacent surface sites. This process is accompanied by the reduction of the Cu centers of the metal–organic complex, indicating that it may be the rate-limiting reaction that leads to further fragmentation of the ligands.
Group B Streptococcus Surface Protein[beta]: Structural Characterization of a Complement Factor H?Bi
Explore the source record for details and available documents.
Replication Data for: Evolution of Metastable Structures at Bimetallic Surfaces from Microscopy and Machine-Learning Molecular Dynamics
The data underlying this published work have been made publicly available in this repository as part of the IMASC Data Management Plan. This work was supported as part of the Integrated Mesoscale Architectures for Sustainable Catalysis (IMASC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # DE-SC0012573.
The problem of the structure of the surface of the lunar maria
The results are described of geological and morphological interpretation of large-scale photographs of the surface of lunar maria. A morphological classification is proposed for small craters. It is shown that the classification of a crater in a given morphological category, reflecting the degree of its morphological maturity, is determined by the age of the given crater. A check on the nature of distribution of small craters, as done on the basis of the nearest neighbor method, show that the distribution is governed by a near-random law. It is found that variations of the probability density function for the craters conform to a normal distribution law. An empirical relation is found for the coefficient of variation as a function of crater diameter and the dimensions of the area on which the counts are made. The rockfalls near craters of various morphological classes are described.
Stimulated electron tunneling in metal-barrier-metal structures due to surface plasmons
Explore the source record for details and available documents.
Mapping of lithological units, structural units and surface drainage using Skylab data
There are no author-identified significant results in this report.
Improved Surface of Titanium Structure
Potential tooling pickup not acceptable on sandwich panels that have face sheets 0.016 in. (0.41 mm) thick. In this application, problem eliminated by changing tooling slipsheet from type 321 CRES to type 430 stainless steel and coating both slipsheet and face sheet with boron nitride powder and binder thinned in acetone.
Scattering from dielectric structures above impedance surfaces and resistive sheets
Interest in understanding of electromagnetic interaction with rough surfaces has prompted the study of scattering from typical dielectric humps over impedance surfaces. It is shown that the Green's function of the problem for a resistive sheet resembles that of the impedance surface. Hence both problems are considered here. A numerical solution for the scattered field of a two-dimensional dielectric object, possibly inhomogeneous, with arbitrary cross section above the impedance surface or resistive sheet is sought. First the Green's function of the problem is derived based on the exact image theory. This form of the Green's function is amenable to numerical computation. Then the induced polarization currents are calculated by casting the integral equations into a matrix equation via the method of moments. Numerical problems in calculation of the Green's function when both source and observation points are close to the surface are discussed. Comparison of numerical results with a perturbation solution shows excellent agreement between the two methods.
A new response surface approach for structural reliability analysis
This paper describes a new approach for computing structural reliability by post-processing previously computed probabilistic results for stress and strength. The objective is to provide an accurate method whereby independent probabilistic analyses for stress and strength functions can be performed independently and combined at a later time to compute probability of failure. The method provides a capability for testing different strength measures without the need for re-computing the probabilistic stress response. The proposed approach takes full account of the basic random variables effecting both stress and strength, and the failure region in the variable space identified during separate stress/strength probabilistic analyses. A simple closed-form example and a more complex analysis of a turbine blade subject to creep rupture is used to illustrate the method.
Concerning Apparent Similarity of Structures of Fluoropolymer Surfaces Exposed to an Argon Plasma or Argon Ion Beam
X-ray photoelectron spectroscopy (XPS) C(sub 1s) spectra of fluoropolymers exposed to either an argon plasma or argon ion beam show remarkable similarity, implying that the surface-modification reactions for these two processes likely proceed through comparable mechanisms, revolving predominantly ion-surface interactions. The importance of working with a monochromatized x-ray source for XPS analysis of the surface-modified fluoropolymers is once again emphasized.
Concerning apparent similarity of structures of fluoropolymer surfaces exposed to an argon plasma or argon ion beam
No abstract available
The Vertical Structure of Vegetated Surfaces from Interferometric and Polarimetric Radar Data
Explore the source record for details and available documents.
Estimation of subsurface thermal structure using sea surface height and sea surface temperature
A method of determining a subsurface temperature in a body of water is disclosed. The method includes obtaining surface temperature anomaly data and surface height anomaly data of the body of water for a region of interest, and also obtaining subsurface temperature anomaly data for the region of interest at a plurality of depths. The method further includes regressing the obtained surface temperature anomaly data and surface height anomaly data for the region of interest with the obtained subsurface temperature anomaly data for the plurality of depths to generate regression coefficients, estimating a subsurface temperature at one or more other depths for the region of interest based on the generated regression coefficients and outputting the estimated subsurface temperature at the one or more other depths. Using the estimated subsurface temperature, signal propagation times and trajectories of marine life in the body of water are determined.