Working group written presentation: Trapped radiation effects

The results of the Trapped Radiation Effects Panel for the Space Environmental Effects on Materials Workshop are presented. The needs of the space community for new data regarding effects of the space environment on materials, including electronics are listed. A series of questions asked of each of the panels at the workshop are addressed. Areas of research which should be pursued to satisfy the requirements for better knowledge of the environment and better understanding of the effects of the energetic charged particle environment on new materials and advanced electronics technology are suggested

Density-functional study of hydrogen chemisorption on vicinal Si(001) surfaces

Relaxed atomic geometries and chemisorption energies have been calculated for the dissociative adsorption of molecular hydrogen on vicinal Si(001) surfaces. We employ density-functional theory, together with a pseudopotential for Si, and apply the generalized gradient approximation by Perdew and Wang to the exchange-correlation functional. We find the double-atomic-height rebonded D_B step, which is known to be stable on the clean surface, to remain stable on partially hydrogen-covered surfaces. The H atoms preferentially bind to the Si atoms at the rebonded step edge, with a chemisorption energy difference with respect to the terrace sites of >sim 0.1 eV. A surface with rebonded single atomic height S_A and S_B steps gives very similar results. The interaction between H-Si-Si-H mono-hydride units is shown to be unimportant for the calculation of the step-edge hydrogen-occupation. Our results confirm the interpretation and results of the recent H_2 adsorption experiments on vicinal Si surfaces by Raschke and Hoefer described in the preceding paper.Comment: 13 pages, 8 figures, submitted to Phys. Rev. B. Other related publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm

Wear Testing and Analysis of Ion Engine Discharge Cathode Keeper

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77116/1/AIAA-4441-635.pd

Erosion Processes of the Discharge Cathode Assembly of Ring-Cusp Gridded Ion Thrusters

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77019/1/AIAA-2006-3558-252.pd

Measurement of 30-Centimeter Ion Thruster Discharge Cathode Erosion

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76209/1/AIAA-22982-649.pd

Atomic-scale visualization of initial growth of homoepitaxial SrTiO3 thin film on an atomically ordered substrate

The initial homoepitaxial growth of SrTiO3 on a (\surd13\times\surd13) - R33.7{\deg}SrTiO3(001) substrate surface, which can be prepared under oxide growth conditions, is atomically resolved by scanning tunneling microscopy. The identical (\surd13\times\surd13) atomic structure is clearly visualized on the deposited SrTiO3 film surface as well as on the substrate. This result indicates the transfer of the topmost Ti-rich (\surd13\times\surd13) structure to the film surface and atomic-scale coherent epitaxy at the film/substrate interface. Such atomically ordered SrTiO3 substrates can be applied to the fabrication of atom-by-atom controlled oxide epitaxial films and heterostructures

Structural and Electrical Characterization of Bi2Se3 Nanostructures Grown by Metalorganic Chemical Vapor Deposition

We characterize nanostructures of Bi2Se3 that are grown via metalorganic chemical vapor deposition using the precursors diethyl selenium and trimethyl bismuth. By adjusting growth parameters, we obtain either single-crystalline ribbons up to 10 microns long or thin micron-sized platelets. Four-terminal resistance measurements yield a sample resistivity of 4 mOhm-cm. We observe weak anti-localization and extract a phase coherence length l_phi = 178 nm and spin-orbit length l_so = 93 nm at T = 0.29 K. Our results are consistent with previous measurements on exfoliated samples and samples grown via physical vapor deposition.Comment: Related papers at http://pettagroup.princeton.ed

Cytokines and Inflammatory Mediators [30-39]: 30. The LPS Stimulated Production of Interleukin-10 is not Associated with -819C/T and -592C/A Promoter Polymorphisms in Healthy Indian Subjects

Background: Interleukin-10 is a pivotal immunoregulatory cytokine with pleiotropic effects on the immune system. IL-10 promoter polymorphisms have been associated with disease susceptibility and the ability to secrete IL-10 in vitro. We suspected that the association of the widely studied -819C/T and -592C/A polymorphisms with the IL-10 production might vary between ethnic groups. Therefore, we examined the association of -819 C/T and -592 C/A promoter polymorphisms with in vitro LPS stimulated secretion of IL-10 in normal healthy Indian volunteers. Methods: Peripheral blood was collected from 103 healthy volunteers and diluted whole blood cultures were set up with 100 ng/ml of LPS as stimulant: supernatant was collected at 24 h and IL-10 levels were assayed by ELISA. Genotyping was done for -819C/T polymorphism in 101 individuals and -592C/A polymorphism in 68 individuals by polymerase chain reaction followed by RFLP. The differences in IL-10 production between the genotypes were analysed by ANOVA. Results: There were 30, 47 and 24 individuals with the CC, CT and TT genotypes with a minor allele (T) frequency of 47% for the -819C/T polymorphism. The CC and TT genotypes at position -819 were strongly associated with CC and AA genotypes at -592 position suggestive of strong linkage disequilibrium. There was no association between the -819 genotype and the in vitro LPS stimulated IL-10 levels. Conclusions: The -819C/T and the -592 C/A polymorphisms of the IL-10 promoter region are not significantly associated with LPS stimulated IL-10 production healthy Indian subjects. Disclosure statement: All authors have declared no conflicts of interes