Resource Type

Geometrical dependence of the low-frequency noise in superconducting flux qubits (open access)

Geometrical dependence of the low-frequency noise in superconducting flux qubits

Article reporting on a study of a series of 85 devices of vary design using a general method for directly measuring the low-frequency flux noise (below 10 Hz) in compound Josephson-junction superconducting flux qubits. The results support the hypothesis that local impurities in the vicinity of the qubit wiring are a key source of low-frequency flux noise in superconducting devices.
Date: February 26, 2009
Creator: Lanting, T.; Berkley, A. J.; Bumble, B.; Bunyk, P.; Fung, A.; Johansson, J. et al.
System: The UNT Digital Library
Prodrugs of Thyrotropin-Releasing Hormone and Related Peptides as Central Nervous System Agents (open access)

Prodrugs of Thyrotropin-Releasing Hormone and Related Peptides as Central Nervous System Agents

This article is a review of prodrug design for brain delivery of small- and medium-sized neuropeptides, focusing on thyrotropin-releasing hormone and structurally related peptides as examples.
Date: February 6, 2009
Creator: Prokai-Tatrai, Katalin & Prókai, László, 1958-
System: The UNT Digital Library
An Updating System for the Gridded Population Database of China Based on Remote Sensing, GIS and Spatial Database Technologies (open access)

An Updating System for the Gridded Population Database of China Based on Remote Sensing, GIS and Spatial Database Technologies

Describes the development of a Spatial Population Updating System (SPUS) for updating the gridded population database of China based on remote sensing, GIS and spatial database technologies, with a spatial resolution of 1 km by 1 km.
Date: February 20, 2009
Creator: Yang, Xiaohuan; Huang, Yaohuan; Dong, Pinliang; Jiang, Dong & Liu, Honghui
System: The UNT Digital Library
Self-organization of engineered epithelial tubules by differential cellular motility (open access)

Self-organization of engineered epithelial tubules by differential cellular motility

Patterning of developing tissues arises from a number of mechanisms, including cell shape change, cell proliferation, and cell sorting from differential cohesion or tension. Here, we reveal that differences in cell motility can also lead to cell sorting within tissues. Using mosaic engineered mammary epithelial tubules, we found that cells sorted depending on their expression level of the membrane-anchored collagenase matrix metalloproteinase (MMP)-14. These rearrangements were independent of the catalytic activity of MMP14 but absolutely required the hemopexin domain. We describe a signaling cascade downstream of MMP14 through Rho kinase that allows cells to sort within the model tissues. Cell speed and persistence time were enhanced by MMP14 expression, but only the latter motility parameter was required for sorting. These results indicate that differential directional persistence can give rise to patterns within model developing tissues.
Date: February 4, 2009
Creator: Mori, Hidetoshi; Gjorevski, Nikolce; Inman, Jamie L; Bissell, Mina J & Nelson, Celeste M
System: The UNT Digital Library
High quality copy number and genotype data from FFPE samples using Molecular Inversion Probe (MIP) microarrays (open access)

High quality copy number and genotype data from FFPE samples using Molecular Inversion Probe (MIP) microarrays

A major challenge facing DNA copy number (CN) studies of tumors is that most banked samples with extensive clinical follow-up information are Formalin-Fixed Paraffin Embedded (FFPE). DNA from FFPE samples generally underperforms or suffers high failure rates compared to fresh frozen samples because of DNA degradation and cross-linking during FFPE fixation and processing. As FFPE protocols may vary widely between labs and samples may be stored for decades at room temperature, an ideal FFPE CN technology should work on diverse sample sets. Molecular Inversion Probe (MIP) technology has been applied successfully to obtain high quality CN and genotype data from cell line and frozen tumor DNA. Since the MIP probes require only a small ({approx}40 bp) target binding site, we reasoned they may be well suited to assess degraded FFPE DNA. We assessed CN with a MIP panel of 50,000 markers in 93 FFPE tumor samples from 7 diverse collections. For 38 FFPE samples from three collections we were also able to asses CN in matched fresh frozen tumor tissue. Using an input of 37 ng genomic DNA, we generated high quality CN data with MIP technology in 88% of FFPE samples from seven diverse collections. When matched fresh frozen …
Date: February 24, 2009
Creator: Wang, Yuker; Carlton, Victoria E. H.; Karlin-Neumann, George; Sapolsky, Ronald; Zhang, Li; Moorhead, Martin et al.
System: The UNT Digital Library
Plant cell walls throughout evolution: towards a molecular understanding of their design principles (open access)

Plant cell walls throughout evolution: towards a molecular understanding of their design principles

Throughout their life, plants typically remain in one location utilizing sunlight for the synthesis of carbohydrates, which serve as their sole source of energy as well as building blocks of a protective extracellular matrix, called the cell wall. During the course of evolution, plants have repeatedly adapted to their respective niche,which is reflected in the changes of their body plan and the specific design of cell walls. Cell walls not only changed throughout evolution but also are constantly remodelled and reconstructed during the development of an individual plant, and in response to environmental stress or pathogen attacks. Carbohydrate-rich cell walls display complex designs, which together with the presence of phenolic polymers constitutes a barrier for microbes, fungi, and animals. Throughout evolution microbes have co-evolved strategies for efficient breakdown of cell walls. Our current understanding of cell walls and their evolutionary changes are limited as our knowledge is mainly derived from biochemical and genetic studies, complemented by a few targeted yet very informative imaging studies. Comprehensive plant cell wall models will aid in the re-design of plant cell walls for the purpose of commercially viable lignocellulosic biofuel production as well as for the timber, textile, and paper industries. Such knowledge will …
Date: February 16, 2009
Creator: Sarkar, Purbasha; Bosneaga, Elena & Auer, Manfred
System: The UNT Digital Library
Incorporation of crop phenology in Simple Biosphere Model (SiBcrop) to improve land-atmosphere carbon exchanges from croplands (open access)

Incorporation of crop phenology in Simple Biosphere Model (SiBcrop) to improve land-atmosphere carbon exchanges from croplands

In the original paper a mistake in Figure 11 occurred. The corrected version of the figure is provided.
Date: February 10, 2009
Creator: Lokupitiya, Erandathie; Denning, Scott; Paustian, Keith; Baker, Ian; Schaefer, Kevin; Verma, Shashi et al.
System: The UNT Digital Library
FTIR and Raman Study of the LixTiyMn1-yO2 (y = 0, 0.11) Cathodes in Methylpropyl Pyrrolidinium Bis(fluoro-sulfonyl)imide, LiTFSI Electrolyte (open access)

FTIR and Raman Study of the LixTiyMn1-yO2 (y = 0, 0.11) Cathodes in Methylpropyl Pyrrolidinium Bis(fluoro-sulfonyl)imide, LiTFSI Electrolyte

This work demonstrates the protective effect of partial titanium substitution in Li{sub x}Ti{sub 0.11}Mn{sub 0.89}O{sub 2} against surface decomposition in room-temperature ionic liquid (RTILs) cells. Raman microscopy and reflectance Fourier transform IR (FTIR) spectroscopy were used to analyze electrodes recovered from cycled Li/Li{sub x}Ti{sub y}Mn{sub 1-y}O{sub 2} (y=0, 0.11) cells containing the 0.5 mol/kg LiTFSI in P{sub 13}FSI RTIL electrolyte. [TFSI=bis(trifluoromethanesulfonyl)imide.] Raman and FTIR spectra of cycled Li{sub x}MnO{sub 2} cathodes showed many distinct bands that can be attributed to both the electrolyte and electrode decomposition products. The thickness of the amorphous porous layer on the Li{sub x}MnO{sub 2} cathode increased during cycling. The surface degradation of Li{sub x}MnO{sub 2} and precipitation of electrolyte decomposition products contributed to the film growth. Improved cycling behavior was observed in cells containing Li{sub x}Ti{sub 0.11}Mn{sub 0.89}O{sub 2}, yet Raman spectroscopy also showed possible surface degradation. The FTIR spectra of cycled Li{sub x}MnO{sub 2} and Li{sub x}Ti{sub 0.11}Mn{sub 0.89}O{sub 2} cathodes displayed bands characteristic for LiSO{sub 3}CF{sub 3} and Li{sub 2}NSO{sub 2}CF{sub 3}, which originate from the reaction of the TFSI anion with traces of water present in the cell.
Date: February 2, 2009
Creator: Hardwick, L.J.; Lucas, I.T.; Doeff, M.M.; Kostecki, R. & Saint, J.A.
System: The UNT Digital Library
2009 CLEO Plenary Session - OPN Article Questions (open access)

2009 CLEO Plenary Session - OPN Article Questions

None
Date: February 26, 2009
Creator: Moses, Edward
System: The UNT Digital Library
The Dawn of a New Era for High Energy Density Physics (open access)

The Dawn of a New Era for High Energy Density Physics

The field of High Energy Density (HED) physics is on the verge of a revolutionary event - the achievement of fusion ignition in the laboratory. New laser facilities, the OMEGA Extended Performance (EP) laser at the University of Rochester and the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory, greatly extend the range of high energy density (HED) plasma conditions (including ignition) accessible in the laboratory. These conditions are among the most extreme obtainable, with pressures in excess of {approx}1,000,000 atmospheres. Experiments at these facilities will elucidate fundamental new science in astrophysics, materials science, laser-matter interactions, and other areas. The demonstration of fusion ignition will be the culmination of decades of research, and for the first time, will open the burning plasma regime to laboratory exploration. Ignition will spur the development of advanced options for clean, environmentally sustainable energy.
Date: February 26, 2009
Creator: Moses, E.; McCrory, R.; Meyerhofer, D. & Keane, C.
System: The UNT Digital Library
An Investigation of the Influence of Chain Length on the Interfacial Ordering of L-Lysine and L-Proline and Their Homopeptides at Hydrophobic and Hydrophilic Interfaces Studied by Sum Frequency Generation and Quartz Crystal Microbalance (open access)

An Investigation of the Influence of Chain Length on the Interfacial Ordering of L-Lysine and L-Proline and Their Homopeptides at Hydrophobic and Hydrophilic Interfaces Studied by Sum Frequency Generation and Quartz Crystal Microbalance

Sum frequency generation vibrational spectroscopy (SFG) and quartz crystal microbalance with dissipation monitoring (QCM-D) are employed to study the interfacial structure and adsorbed amount of the amino acids l-lysine and l-proline and their corresponding homopeptides, poly-l-lysine and poly-l-proline, at two liquid-solid interfaces. SFG and QCM-D experiments of these molecules are carried out at the interface between phosphate buffered saline at pH 7.4 (PBS) and the hydrophobic deuterated polystyrene (d{sub 8}-PS) surface as well as the interface between PBS and hydrophilic fused silica (SiO{sub 2}). The SFG spectra of the amino acids studied here are qualitatively similar to their corresponding homopeptides; however, the SFG signal from amino acids at the solid/PBS interface is smaller in magnitude relative to their more massive homopeptides at the concentrations studied here. Substantial differences are observed in SFG spectra for each species between the hydrophobic d{sub 8}-PS and the hydrophilic SiO{sub 2} liquid-solid interfaces, suggesting surface-dependent interfacial ordering of the biomolecules. Over the range of concentrations used in this study, QCM-D measurements also indicate that on both surfaces poly-l-lysine adsorbs to a greater extent than its constituent amino acid l-lysine. The opposite trend is demonstrated by poly-l-proline which sticks to both surfaces less extensively than its …
Date: February 23, 2009
Creator: York, R.L.; Holinga, G.J. & Somorjai, G.A.
System: The UNT Digital Library
Citizen Engagement in Post-Hurricane Katrina Planning in Harrison County, Mississippi (open access)

Citizen Engagement in Post-Hurricane Katrina Planning in Harrison County, Mississippi

This article describes the experiences of Ohio State University’s Knowlton School of Architecture in facilitating a citizen-engagement process for communitywide planning on the Mississippi Gulf Coast.
Date: February 26, 2009
Creator: Evans-Cowley, Jennifer & Zimmerman Gough, Meghan
System: The UNT Digital Library
Search for exclusive Z boson production and observation of high mass p anti-p ---> gamma gamma anti-p ---> pl+ l- anti-p events in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for exclusive Z boson production and observation of high mass p anti-p ---> gamma gamma anti-p ---> pl+ l- anti-p events in p anti-p collisions at s**(1/2) = 1.96-TeV

We present a search for exclusive Z boson production in proton-antiproton collisions at {radical}s = 1.96 TeV, using the CDF II detector at Fermilab. We observe no exclusive Z {yields} {ell}{sup +}{ell}{sup -} candidates and place the first upper limit on the exclusive Z cross section in hadron collisions, {sigma}{sub excl}(Z) < 0.96 pb at 95% confidence level. In addition, we observe eight candidate exclusive dilepton events from the quantum electrodynamic process p{bar p} {yields} p{gamma}{gamma}{bar p} {yields} p{ell}{sup +}{ell}{sup -} {bar p}, and measure the cross section for M{sub {ell}{ell}} > 40 GeV=c{sup 2} and |{eta}{sub {ell}}| < 4 to be {sigma} = 0.24{sub -0.10}{sup +0.13} pb, which is the first measurement for this mass range and is consistent with the standard model prediction.
Date: February 1, 2009
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
System: The UNT Digital Library
Measurement of the Z gamma ---> nu anti-nu gamma cross section and limits on anomalous Z Z gamma and Z gamma gamma couplings in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Measurement of the Z gamma ---> nu anti-nu gamma cross section and limits on anomalous Z Z gamma and Z gamma gamma couplings in p anti-p collisions at s**(1/2) = 1.96-TeV

We present the first observation of the Z{gamma} {yields}{nu}{bar {nu}}{gamma} process at the Tevatron at 5.1 standard deviations significance, based on 3.6 fb{sup -1} of integrated luminosity collected with the D0 detector at the Fermilab Tevatron p{bar p} Collider at {radical}s = 1.96 TeV. The measured Z{gamma} cross section multiplied by the branching fraction of Z {yields} {nu}{bar {nu}} is 32 {+-} 9(stat. + syst.) {+-} 2(lumi.) fb for the photon E{sub T} > 90 GeV. It is in agreement with the standard model prediction of 39 {+-} 4 fb. We set the most restrictive limits on anomalous trilinear Z{gamma}{gamma} and ZZ{gamma} gauge boson couplings at a hadron collider to date, with three constraints being the world's strongest.
Date: February 1, 2009
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, Bannanje Sripath; Adams, M.; Adams, T. et al.
System: The UNT Digital Library
Chemical and electronic characterization of cobalt in Lanthanumperovskites. Effects of Strontium substitution (open access)

Chemical and electronic characterization of cobalt in Lanthanumperovskites. Effects of Strontium substitution

Two different cobaltites, LaCoO{sub 3} and La{sub 0.5}Sr{sub 0.5}CoO{sub 3-{delta}}, have been prepared and characterized by means of high energy Co K-edge and low energy O K-edge X-ray absorption spectroscopy (XAS). The partial substitution of La(III) by Sr(II) species induces important changes in the reactivity and electronic state of the perovskite, while little or no changes can be detected in the formal oxidation state of cobalt atoms. The presence of strontium cations induces two main effects in the chemical and electronic behavior of the perovskite. The charge balance with Sr(II) species is reached by the formation of oxygen vacancies throughout the network, which increases the reactivity of the perovskite, now more reducible than the original LaCoO{sub 3} perovskite. O K-edge XAS experiments indicate that the Sr(II) species cause d electrons of cobalt cations to change from low to high spin configuration. Our data allow us to propose that this change in spin multiplicity is induced by the bigger size of Sr(II) cations, which aligns the Co-O-Co atoms, and favors the overlapping of {pi}-symmetry cobalt and oxygen orbitals, reducing the splitting energy of e{sub g} and t{sub 2g} levels.
Date: February 6, 2009
Creator: Hueso, Jose L.; Holgado, Juan P.; Pereniguez, Rosa; Mun, Simon; Salmeron, Miquel & Caballero, Alfonso
System: The UNT Digital Library
Measurement of Black Carbon and Particle Number Emission Factors from Individual Heavy-Duty Trucks (open access)

Measurement of Black Carbon and Particle Number Emission Factors from Individual Heavy-Duty Trucks

Emission factors for black carbon (BC) and particle number (PN) were measured from 226 individual heavy-duty (HD) diesel-fueled trucks driving through a 1 km-long California highway tunnel in August 2006. Emission factors were based on concurrent increases in BC, PN, and CO{sub 2}B concentrations (measured at 1 Hz) that corresponded to the passage of individual HD trucks. The distributions of BC and PN emission factors from individual HD trucks are skewed, meaning that a large fraction of pollution comes from a small fraction of the in-use vehicle fleet. The highest-emitting 10% of trucks were responsible for {approx} 40% of total BC and PN emissions from all HD trucks. BC emissions were log-normally distributed with a mean emission factor of 1.7 g kg {sup -1} and maximum values of {approx} 10 g kg{sup -1}. Corresponding values for PN emission factors were 4.7 x 10{sup 15} and 4 x 10{sup 16} kg{sup -1}. There was minimal overlap among high-emitters of these two pollutants: only 1 of the 226 HD trucks measured was found to be among the highest 10% for both BC and PN. Monte Carlo resampling of the distribution of BC emission factors observed in this study revealed that uncertainties (1{sigma}) …
Date: February 2, 2009
Creator: Ban-Weiss, George A.; Lunden, Melissa M.; Kirchstetter, Thomas W. & Harley, Robert A.
System: The UNT Digital Library
Alternative pre-mRNA splicing switches modulate gene expression in late erythropoiesis (open access)

Alternative pre-mRNA splicing switches modulate gene expression in late erythropoiesis

Differentiating erythroid cells execute a unique gene expression program that insures synthesis of the appropriate proteome at each stage of maturation. Standard expression microarrays provide important insight into erythroid gene expression but cannot detect qualitative changes in transcript structure, mediated by RNA processing, that alter structure and function of encoded proteins. We analyzed stage-specific changes in the late erythroid transcriptome via use of high-resolution microarrays that detect altered expression of individual exons. Ten differentiation-associated changes in erythroblast splicing patterns were identified, including the previously known activation of protein 4.1R exon 16 splicing. Six new alternative splicing switches involving enhanced inclusion of internal cassette exons were discovered, as well as 3 changes in use of alternative first exons. All of these erythroid stage-specific splicing events represent activated inclusion of authentic annotated exons, suggesting they represent an active regulatory process rather than a general loss of splicing fidelity. The observation that 3 of the regulated transcripts encode RNA binding proteins (SNRP70, HNRPLL, MBNL2) may indicate significant changes in the RNA processing machinery of late erythroblasts. Together, these results support the existence of a regulated alternative pre-mRNA splicing program that is critical for late erythroid differentiation.
Date: February 3, 2009
Creator: Yamamoto, Miki L.; Clark, Tyson A.; Gee, Sherry L.; Kang, Jeong-Ah; Schweitzer, Anthony C.; Wickrema, Amittha et al.
System: The UNT Digital Library
Elements of Successful and Safe Fusion Experiment Operations (open access)

Elements of Successful and Safe Fusion Experiment Operations

A group of fusion safety professionals contribute to a Joint Working Group (JWG) that performs occupational safety walkthroughs of US and Japanese fusion experiments on a routine basis to enhance the safety of visiting researchers. The most recent walkthrough was completed in Japan in March 2008 by the US Safety Monitor team. This paper gives the general conclusions on fusion facility personnel safety that can be drawn from the series of walkthroughs.
Date: February 3, 2009
Creator: Rule, K.; Cadwallader, L.; Takase, Y.; Norimatsu, T.; Kaneko, O.; Sato, M. et al.
System: The UNT Digital Library
Pressure analysis of the hydromechanical fracture behaviour in stimulated tight sedimentary geothermalreservoirs (open access)

Pressure analysis of the hydromechanical fracture behaviour in stimulated tight sedimentary geothermalreservoirs

None
Date: February 15, 2009
Creator: Wessling, S.; Junker, R.; Rutqvist, J.; Silin, D.; Sulzbacher, H.; Tischner, T. et al.
System: The UNT Digital Library
STEAM REFORMING TECHNOLOGY DEMONSTRATION FOR THE DESTRUCTION OF ORGANICS ON ACTUAL DOE SAVANNAH RIVER SITE TANK 48H WASTE 9138 (open access)

STEAM REFORMING TECHNOLOGY DEMONSTRATION FOR THE DESTRUCTION OF ORGANICS ON ACTUAL DOE SAVANNAH RIVER SITE TANK 48H WASTE 9138

This paper describes the design of the Bench-scale Steam Reformer (BSR); a processing unit for demonstrating steam reforming technology on actual radioactive waste [1]. It describes the operating conditions of the unit used for processing a sample of Savannah River Site (SRS) Tank 48H waste. Finally, it compares the results from processing the actual waste in the BSR to processing simulant waste in the BSR to processing simulant waste in a large pilot scale unit, the Fluidized Bed Steam Reformer (FBSR), operated at Hazen Research Inc. in Golden, CO. The purpose of this work was to prove that the actual waste reacted in the same manner as the simulant waste in order to validate the work performed in the pilot scale unit which could only use simulant waste.
Date: February 24, 2009
Creator: Burket, P
System: The UNT Digital Library
The Phase Diagram of QCD and Some Issues of Large N_c (open access)

The Phase Diagram of QCD and Some Issues of Large N_c

The large N{sub c} limit provides a good phenomenology of meson spectra and interactions, I discuss some problems with applying the large N{sub c} approximation to the description of baryons, and point out a number of apparent paradoxes and phenomenological difficulties.
Date: February 28, 2009
Creator: McLerran, L.
System: The UNT Digital Library
Functional autonomy of distant-acting human enhancers (open access)

Functional autonomy of distant-acting human enhancers

Many human genes are associated with dispersed arrays of transcriptional enhancers that regulate their expression in time and space. Studies in invertebrate model systems have suggested that these elements function as discrete and independent regulatory units, but the in vivo combinatorial properties of vertebrate enhancers remain poorly understood. To explore the modularity and regulatory autonomy of human developmental enhancers, we experimentally concatenated up to four enhancers from different genes and used a transgenic mouse assay to compare the in vivo activity of these compound elements with that of the single modules. In all of the six different combinations of elements tested, the reporter gene activity patterns were additive without signs of interference between the individual modules, indicating that regulatory specificity was maintained despite the presence of closely-positioned heterologous enhancers. Even in cases where two elements drove expression in close anatomical proximity, such as within neighboring subregions of the developing limb bud, the compound patterns did not show signs of cross-inhibition between individual elements or novel expression sites. These data indicate that human developmental enhancers are highly modular and functionally autonomous and suggest that genomic enhancer shuffling may have contributed to the evolution of complex gene expression patterns in vertebrates
Date: February 19, 2009
Creator: Visel, Axel; Akiyama, Jennifer A.; Shoukry, Malak; Afzal, Veena; Rubin, Edward M. & Pennacchio, Len A.
System: The UNT Digital Library
Genome analysis of Elusimicrobium minutum, the first cultivated representative of the Elusimicrobia phylum (formerly Termite Group 1) (open access)

Genome analysis of Elusimicrobium minutum, the first cultivated representative of the Elusimicrobia phylum (formerly Termite Group 1)

The candidate phylum Termite group 1 (TG1), is regularly 1 encountered in termite hindguts but is present also in many other habitats. Here we report the complete genome sequence (1.64 Mbp) of Elusimicrobium minutum strain Pei191{sup T}, the first cultured representative of the TG1 phylum. We reconstructed the metabolism of this strictly anaerobic bacterium isolated from a beetle larva gut and discuss the findings in light of physiological data. E. minutum has all genes required for uptake and fermentation of sugars via the Embden-Meyerhof pathway, including several hydrogenases, and an unusual peptide degradation pathway comprising transamination reactions and leading to the formation of alanine, which is excreted in substantial amounts. The presence of genes encoding lipopolysaccharide biosynthesis and the presence of a pathway for peptidoglycan formation are consistent with ultrastructural evidence of a Gram-negative cell envelope. Even though electron micrographs showed no cell appendages, the genome encodes many genes putatively involved in pilus assembly. We assigned some to a type II secretion system, but the function of 60 pilE-like genes remains unknown. Numerous genes with hypothetical functions, e.g., polyketide synthesis, non-ribosomal peptide synthesis, antibiotic transport, and oxygen stress protection, indicate the presence of hitherto undiscovered physiological traits. Comparative analysis of …
Date: February 1, 2009
Creator: Herlemann, D. P. R.; Geissinger, O.; Ikeda-Ohtsubo, W.; Kunin, V.; Sun, H.; Lapidus, A. et al.
System: The UNT Digital Library
Comparison of fast 3D simulation and actinic inspection for EUV masks with buries defects (open access)

Comparison of fast 3D simulation and actinic inspection for EUV masks with buries defects

Aerial images for isolated defects and the interactions of defects with features are compared between the Actinic Inspection Tool (AIT) at Lawrence Berkeley National Laboratory (LBNL) and the fast EUV simulation program RADICAL. Comparisons between AIT images from August 2007 and RADICAL simulations are used to extract aberrations. At this time astigmatism was the dominant aberration with a value of 0.55 waves RMS. Significant improvements in the imaging performance of the AIT were made between August 2007 and December 2008. A good match will be shown between the most recent AIT images and RADICAL simulations without aberrations. These comparisons will demonstrate that a large defect, in this case 7nm tall on the surface, is still printable even if it is centered under the absorber line. These comparisons also suggest that the minimum defect size is between 1.5nm and 0.8nm surface height because a 1.5nm defect was printable but a 0.8nm was not. Finally, the image of a buried defect near an absorber line through focus will demonstrate an inversion in the effect of the defect from a protrusion of the dark line into the space to a protrusion of the space into the line.
Date: February 23, 2009
Creator: Clifford, C. H.; Wiraatmadja, S.; Chan, T. T.; Neureuther, A. R.; Goldberg, K. A.; Mochi, I. et al.
System: The UNT Digital Library