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Wavelength-specific reflections: A decade of EUV actinic mask inspection research (open access)

Wavelength-specific reflections: A decade of EUV actinic mask inspection research

Mask inspection is essential for the success of any pattern-transfer lithography technology, and EUV Lithography in particular faces unique challenges. EUV masks resonant-reflective multilayer coatings have a narrow, wavelength-specific response that dramatically affects the way that defects appear, or disappear, at various illuminating wavelengths. Furthermore, the ever-shrinking size of 'critical' defects limits the potential effectiveness of DUV inspection techniques over time. Researchers pursuing numerous ways of finding and characterizing defects on EUV masks and have met with varying degrees of success. Their lessons inform the current, urgent exploration to select the most effective techniques for high-volume manufacturing. Ranging from basic research and demonstration experiments to commercial inspection tool prototypes, we survey the recent history of work in this area, including sixteen projects in Europe, Asia, and America. Solutions range from scanning beams to microscopy, dark field imaging to pattern transfer.
Date: December 31, 2010
Creator: Goldberg, Kenneth & Mochi, Iacopo
System: The UNT Digital Library
Measurements of isotope effects in the photoionization of N2 and implications for Titan's atmosphere (open access)

Measurements of isotope effects in the photoionization of N2 and implications for Titan's atmosphere

Isotope effects in the non-dissociative photoionization of molecular nitrogen (N2 + h nu -> N2+ + e-) may play a role in determining the relative abundances of isotopic species containing nitrogen in interstellar clouds and planetary atmospheres but have not been previously measured. Measurements of the photoionization efficiency spectra of 14N2, 15N14N, and 15N2 from 15.5 to 18.9 eV (65.6-80.0 nm) using the Advanced Light Source at Lawrence Berkeley National Laboratory show large differences in peak energies and intensities, with the ratio of the energy-dependent photoionization cross-sections, sigma(14N2)/sigma(15N14N), ranging from 0.4 to 3.5. Convolving the cross-sections with the solar flux and integrating over the energies measured, the ratios of photoionization rate coefficients are J(15N14N)/J(14N2)=1.00+-0.02 and J(15N2)/J(14N2)=1.00+-0.02, suggesting that isotopic fractionation between N2 and N2+ should be small under such conditions. In contrast, in a one-dimensional model of Titan's atmosphere, isotopic self-shielding of 14N2 leads to values of J(15N14N)/J(14N2) as large as ~;;1.17, larger than under optically thin conditions but still much smaller than values as high as ~;;29 predicted for N2 photodissociation. Since modeled photodissociation isotope effects overpredict the HC15N/HC14N ratio in Titan's atmosphere, and since both N atoms and N2+ ions may ultimately lead to the formation of HCN, …
Date: December 30, 2010
Creator: Croteau, Philip; Randazzo, John B.; Kostko, Oleg; Ahmed, Musahid; Liang, Mao-Chang; Yung, Yuk L. et al.
System: The UNT Digital Library
Judging Edward Teller: A Closer Look at One of the Most Influential Scientists of the Twentieth Century (open access)

Judging Edward Teller: A Closer Look at One of the Most Influential Scientists of the Twentieth Century

Much has been written about Edward TEller, but little of it is objective. Given, on the one hand, his position as one of the most inventive theoretical physicists of the 20th century, and on the other, his central role in the development and advocacy of thermonuclear weapons, one might imagine it impossible at this point in history to write a scholarly, impartial account of Teller's life and his impact. Now, however, Istvan Hargittai, a prominent Hungarian physical chemist and historian of science, has written a balanced, thoughtful, and beautifully research biography that comes closest. Hargittai is uniquely qualified for this difficult task. Coming a generation and a half later from a similar Hungarian-Jewish background, Hargittai understands well the influences and terrible events that shaped Teller. The advent of virulent, political anti-Semitism, first in Hungary and then in Germany, made Teller twice a refugee. Both Teller and Hargittai lost close family in the Holocaust; Hargittai was himself liberated from a Nazi concentration camp as a child. While Teller was in the US by then, his and Hargittai's surviving family members in Hungary suffered mistreatment at the hands of the postwar Hungarian Communist dictatorship. Hargittai's informed Eastern European perspective also provides a …
Date: December 29, 2010
Creator: Libby, S B
System: The UNT Digital Library
Size-dependent Si Nanowire Mechanics are Invariant to Changes in the Surface State (open access)

Size-dependent Si Nanowire Mechanics are Invariant to Changes in the Surface State

None
Date: December 29, 2010
Creator: Lee, B & Rudd, R E
System: The UNT Digital Library
Adaptation of a cubic smoothing spline algortihm for multi-channel data stitching at the National Ignition Facility (open access)

Adaptation of a cubic smoothing spline algortihm for multi-channel data stitching at the National Ignition Facility

Some diagnostics at the National Ignition Facility (NIF), including the Gamma Reaction History (GRH) diagnostic, require multiple channels of data to achieve the required dynamic range. These channels need to be stitched together into a single time series, and they may have non-uniform and redundant time samples. We chose to apply the popular cubic smoothing spline technique to our stitching problem because we needed a general non-parametric method. We adapted one of the algorithms in the literature, by Hutchinson and deHoog, to our needs. The modified algorithm and the resulting code perform a cubic smoothing spline fit to multiple data channels with redundant time samples and missing data points. The data channels can have different, time-varying, zero-mean white noise characteristics. The method we employ automatically determines an optimal smoothing level by minimizing the Generalized Cross Validation (GCV) score. In order to automatically validate the smoothing level selection, the Weighted Sum-Squared Residual (WSSR) and zero-mean tests are performed on the residuals. Further, confidence intervals, both analytical and Monte Carlo, are also calculated. In this paper, we describe the derivation of our cubic smoothing spline algorithm. We outline the algorithm and test it with simulated and experimental data.
Date: December 28, 2010
Creator: Brown, C; Adcock, A; Azevedo, S; Liebman, J & Bond, E
System: The UNT Digital Library
Numerical simulation studies of the long-term evolution of a CO2 plume in a saline aquifer with a sloping caprock (open access)

Numerical simulation studies of the long-term evolution of a CO2 plume in a saline aquifer with a sloping caprock

We have used the TOUGH2-MP/ECO2N code to perform numerical simulation studies of the long-term behavior of CO{sub 2} stored in an aquifer with a sloping caprock. This problem is of great practical interest, and is very challenging due to the importance of multi-scale processes. We find that the mechanism of plume advance is different from what is seen in a forced immiscible displacement, such as gas injection into a water-saturated medium. Instead of pushing the water forward, the plume advances because the vertical pressure gradients within the plume are smaller than hydrostatic, causing the groundwater column to collapse ahead of the plume tip. Increased resistance to vertical flow of aqueous phase in anisotropic media leads to reduced speed of updip plume advancement. Vertical equilibrium models that ignore effects of vertical flow will overpredict the speed of plume advancement. The CO{sub 2} plume becomes thinner as it advances, yet the speed of advancement remains constant over the entire simulation period of up to 400 years, with migration distances of more than 80 km. Our simulations include dissolution of CO{sub 2} into the aqueous phase and associated density increase, and molecular diffusion. However, no convection develops in the aqueous phase because it …
Date: December 28, 2010
Creator: Pruess, K. & Nordbotten, J.
System: The UNT Digital Library
Biospecimen Reporting for Improved Study Quality (open access)

Biospecimen Reporting for Improved Study Quality

Human biospecimens are subjected to collection, processing, and storage that can significantly alter their molecular composition and consistency. These biospecimen preanalytical factors, in turn, influence experimental outcomes and the ability to reproduce scientific results. Currently, the extent and type of information specific to the biospecimen preanalytical conditions reported in scientific publications and regulatory submissions varies widely. To improve the quality of research that uses human tissues, it is crucial that information on the handling of biospecimens be reported in a thorough, accurate, and standardized manner. The Biospecimen Reporting for Improved Study Quality (BRISQ) recommendations outlined herein are intended to apply to any study in which human biospecimens are used. The purpose of reporting these details is to supply others, from researchers to regulators, with more consistent and standardized information to better evaluate, interpret, compare, and reproduce the experimental results. The BRISQ guidelines are proposed as an important and timely resource tool to strengthen communication and publications on biospecimen-related research and to help reassure patient contributors and the advocacy community that their contributions are valued and respected.
Date: December 27, 2010
Creator: Moore, Ph.D., Helen M.; Kelly, Ph.D., Andrea B.; Jewell, Ph.D., Scott D.; McShane, Ph.D., Lisa M.; Clark, M.D., Douglas P.; Greenspan, M.D., Renata et al.
System: The UNT Digital Library
The Genome of Woodland Strawberry (Fragaria Vesca) (open access)

The Genome of Woodland Strawberry (Fragaria Vesca)

This article reports the draft F. vesca genome, which was sequenced to x39 coverage using second-generation technology, assembled de novo and then anchored to the genetic linkage map into seven pseudochromosomes.
Date: December 26, 2010
Creator: Shulaev, Vladimir; Sargent, Daniel J.; Crowhurst, Ross N.; Mockler, Todd C.; Folkerts, Otto; Delcher, Arthur et al.
System: The UNT Digital Library
Accelerator Challenges and Opportunities for Future Neutrino Experiments (open access)

Accelerator Challenges and Opportunities for Future Neutrino Experiments

There are three types of future neutrino facilities currently under study, one based on decays of stored beta-unstable ion beams (?Beta Beams?), one based on decays of stored muon beams (?Neutrino Factory?), and one based on the decays of an intense pion beam (?Superbeam?). In this paper we discuss the challenges each design team must face and the R&D being carried out to turn those challenges into technical opportunities. A new program, the Muon Accelerator Program, has begun in the U.S. to carry out the R&D for muon-based facilities, including both the Neutrino Factory and, as its ultimate goal, a Muon Collider. The goals of this program will be briefly described.
Date: December 24, 2010
Creator: Zisman, Michael S
System: The UNT Digital Library
Progress on a Be Cavity Design (open access)

Progress on a Be Cavity Design

Previous RF experiments with normal-conducting cavities have demonstrated that there is a significant degradation in maximum gradient when the cavity is subjected to a strong axial magnetic field. We have developed a model suggesting that a cavity with beryllium walls may perform better than copper cavities. In this paper we outline the issues that led us to propose fabricating a Be-wall cavity. We also discuss a concept for fabricating such a cavity and mention some of the manufacturing issues we expect to face.
Date: December 24, 2010
Creator: Li, D.; Palmer, R.; Stratakis, D.; Virostek, S. & Zisman, Michael S.
System: The UNT Digital Library
Climate change and forests in India: note from the guest editors (open access)

Climate change and forests in India: note from the guest editors

Forestry is one of the most important sectors in the context of climate change. It lies at the center-stage of global mitigation and adaptation efforts. Yet, it is one of the least understood sectors, especially in tropical zones, which constitute a significant portion of the global forests. Recently, there has been a growing interest in forests in addressing global climate change. The IPCC Assessment Report 4 (2007) Chapters related to forests have highlighted the limited number of studies on the impact of climate change on forests at the regional, national and sub-national level, while policy makers need information at these scales. Further, implication of projected climate change on mitigation potential of forest sector is only briefly mentioned in the IPCC report, with limited literature to support the conclusions. India is one among the top ten nations in the world in terms of forest cover. It is also sixth among the tropical countries in terms of forested area. As IPCC Assessment Report 5 work is about to be initiated soon, studies on the impact of climate change on forests as well as the mitigation potential of the forest sector, particularly at regional and national level, will be of great interest to …
Date: December 23, 2010
Creator: Ravindtranath, N.H. & Aaheim, Asbjporn
System: The UNT Digital Library
Identification of functional elements and regulatory circuits by Drosophila modENCODE (open access)

Identification of functional elements and regulatory circuits by Drosophila modENCODE

To gain insight into how genomic information is translated into cellular and developmental programs, the Drosophila model organism Encyclopedia of DNA Elements (modENCODE) project is comprehensively mapping transcripts, histone modifications, chromosomal proteins, transcription factors, replication proteins and intermediates, and nucleosome properties across a developmental time course and in multiple cell lines. We have generated more than 700 data sets and discovered protein-coding, noncoding, RNA regulatory, replication, and chromatin elements, more than tripling the annotated portion of the Drosophila genome. Correlated activity patterns of these elements reveal a functional regulatory network, which predicts putative new functions for genes, reveals stage- and tissue-specific regulators, and enables gene-expression prediction. Our results provide a foundation for directed experimental and computational studies in Drosophila and related species and also a model for systematic data integration toward comprehensive genomic and functional annotation. Several years after the complete genetic sequencing of many species, it is still unclear how to translate genomic information into a functional map of cellular and developmental programs. The Encyclopedia of DNA Elements (ENCODE) (1) and model organism ENCODE (modENCODE) (2) projects use diverse genomic assays to comprehensively annotate the Homo sapiens (human), Drosophila melanogaster (fruit fly), and Caenorhabditis elegans (worm) genomes, through systematic …
Date: December 22, 2010
Creator: Roy, Sushmita; Ernst, Jason; Kharchenko, Peter V.; Kheradpour, Pouya; Negre, Nicolas; Eaton, Matthew L. et al.
System: The UNT Digital Library
Persistence of gamma-H2AX and 53BP1 foci in proliferating and nonproliferating human mammary epithelial cells after exposure to gamma-rays or iron ions (open access)

Persistence of gamma-H2AX and 53BP1 foci in proliferating and nonproliferating human mammary epithelial cells after exposure to gamma-rays or iron ions

To investigate {gamma}-H2AX (phosphorylated histone H2AX) and 53BP1 (tumour protein 53 binding protein No. 1) foci formation and removal in proliferating and non-proliferating human mammary epithelial cells (HMEC) after exposure to sparsely and densely ionizing radiation under different cell culture conditions. HMEC cells were grown either as monolayers (2D) or in extracellular matrix to allow the formation of acinar structures in vitro (3D). Foci numbers were quantified by image analysis at various time points after exposure. Our results reveal that in non-proliferating cells under 2D and 3D cell culture conditions, iron-ion induced {gamma}-H2AX foci were still present at 72 h after exposure, although 53BP1 foci returned to control levels at 48 h. In contrast in proliferating HMEC, both {gamma}-H2AX and 53BP1 foci decreased to control levels during the 24-48 h time interval after irradiation under 2D conditions. Foci numbers decreased faster after {gamma}-ray irradiation and returned to control levels by 12 h regardless of marker, cell proliferation status, and cell culture condition. Conclusions: The disappearance of radiation induced {gamma}-H2AX and 53BP1 foci in HMEC have different dynamics that depend on radiation quality and proliferation status. Notably, the general patterns do not depend on the cell culture condition (2D versus 3D). …
Date: December 22, 2010
Creator: Groesser, Torsten; Chang, Hang; Fontenay, Gerald; Chen, James; Costes, Sylvain V.; Barcellos-Hoff, Mary Helen et al.
System: The UNT Digital Library
A Piecewise Bi-Linear Discontinuous Finite Element Spatial Discretization of the Sn Transport Equation (open access)

A Piecewise Bi-Linear Discontinuous Finite Element Spatial Discretization of the Sn Transport Equation

We present a new spatial discretization of the discrete-ordinates transport equation in two-dimensional Cartesian (X-Y) geometry for arbitrary polygonal meshes. The discretization is a discontinuous finite element method (DFEM) that utilizes piecewise bi-linear (PWBL) basis functions, which are formally introduced in this paper. We also present a series of numerical results on quadrilateral and polygonal grids and compare these results to a variety of other spatial discretizations that have been shown to be successful on these grid types. Finally, we note that the properties of the PWBL basis functions are such that the leading-order piecewise bi-linear discontinuous finite element (PWBLD) solution will satisfy a reasonably accurate diffusion discretization in the thick diffusion limit, making the PWBLD method a viable candidate for many different classes of transport problems.
Date: December 22, 2010
Creator: Bailey, T S; Chang, J H; Warsa, J S & Adams, M L
System: The UNT Digital Library
A Two-Coordinate Nickel Imido Complex That Effects C-H Amination (open access)

A Two-Coordinate Nickel Imido Complex That Effects C-H Amination

This article discusses a two-coordinate nickel imido complex that effects C-H amination.
Date: December 22, 2010
Creator: Laskowski, Carl A.; Miller, Alexander J.M.; Hillhouse, Gregory L. & Cundari, Thomas R., 1964-
System: The UNT Digital Library
The 1969 Oklahoma City Garbage Strike (open access)

The 1969 Oklahoma City Garbage Strike

Article covers the Oklahoma City worker's strike in 1969 when sanitation workers, mostly African Americans, went on strike for higher wages and better working conditions. The article expounds on the reasons for the strike, the attention it received locally and nationally from African American politicians and organizations, and the results of the resolve of the strikers and their supporters.
Date: Winter 2010
Creator: Lowitt, Richard, 1922-2018
System: The Gateway to Oklahoma History
Advantages of a soft protective layer for good signal-to-noise ratio proton radiographs in high debris environments (open access)

Advantages of a soft protective layer for good signal-to-noise ratio proton radiographs in high debris environments

None
Date: December 21, 2010
Creator: Le Galloudec, N. R.; Cobble, J.; Nelson, S. L.; Merwin, A.; Paudel, Y.; Shrestha, I. et al.
System: The UNT Digital Library
Brother Bankers: Frank P. and Hugh M. Johnson, Founders of the First National Bank and Trust Company of Oklahoma City (open access)

Brother Bankers: Frank P. and Hugh M. Johnson, Founders of the First National Bank and Trust Company of Oklahoma City

Article explores the parallel paths in Oklahoma banking history of brothers F. P. and H. M. Johnson. The brothers came from Mississippi to Oklahoma and made names for themselves in their own banking ventures across the state before teaming up to create the First National Bank and Trust Company in Oklahoma City.
Date: Winter 2010
Creator: Hightower, Michael J.
System: The Gateway to Oklahoma History
CHARACTERIZATION OF MODIFIED MONOSODIUM TITANATE - AN IMPROVED SORBENT FOR STRONTIUM AND ACTINIDE SEPARATIONS (open access)

CHARACTERIZATION OF MODIFIED MONOSODIUM TITANATE - AN IMPROVED SORBENT FOR STRONTIUM AND ACTINIDE SEPARATIONS

High-level nuclear waste produced from fuel reprocessing operations at the Savannah River Site (SRS) requires pretreatment to remove {sup 134,137}Cs, {sup 90}Sr, and alpha-emitting radionuclides (i.e., actinides) prior to disposal onsite as low level waste. An inorganic sorbent, monosodium titanate (MST), is currently used to remove {sup 90}Sr and alpha-emitting radionuclides, while a caustic-side solvent extraction process is used for removing {sup 134,137}Cs. A new peroxotitanate material, modified MST, or mMST, has recently been developed and has shown increased removal kinetics and capacity for {sup 90}Sr and alpha-emitting radionuclides compared to the current baseline material, MST. This paper describes recent results focused on further characterization of this material.
Date: December 21, 2010
Creator: Hobbs, D.; Taylor-Pashow, K. & Missimer, D.
System: The UNT Digital Library
Direct observation of imprinted antiferromagnetic vortex state in CoO/Fe/Ag(001) disks (open access)

Direct observation of imprinted antiferromagnetic vortex state in CoO/Fe/Ag(001) disks

In magnetic thin films, a magnetic vortex is a state in which the magnetization vector curls around the center of a confined structure. A vortex state in a thin film disk, for example, is a topological object characterized by the vortex polarity and the winding number. In ferromagnetic (FM) disks, these parameters govern many fundamental properties of the vortex such as its gyroscopic rotation, polarity reversal, core motion, and vortex pair excitation. However, in antiferromagnetic (AFM) disks, though there has been indirect evidence of the vortex state through observations of the induced FM-ordered spins in the AFM disk, they have never been observed directly in experiment. By fabricating single crystalline NiO/Fe/Ag(001) and CoO/Fe/Ag(001) disks and using X-ray Magnetic Linear Dichroism (XMLD), we show direct observation of the vortex state in an AFM disk of AFM/FM bilayer system. We observe that there are two types of AFM vortices, one of which has no analog in FM structures. Finally, we show that a frozen AFM vortex can bias a FM vortex at low temperature.
Date: December 21, 2010
Creator: Wu, J.; Carlton, D.; Park, J. S.; Meng, Y.; Arenholz, E.; Doran, A. et al.
System: The UNT Digital Library
For the Record, Winter 2010-11 (open access)

For the Record, Winter 2010-11

For the Record section including the minutes of the regular quarterly board meeting of the Board of Directors of the Oklahoma Historical Society that was held on July 28, 2010.
Date: Winter 2010
Creator: Oklahoma Historical Society
System: The Gateway to Oklahoma History
Friends of the Osages: John Joseph Mathews's Wah'Kon-Tah and Osage-Quaker Cross-Cultural Collaboration (open access)

Friends of the Osages: John Joseph Mathews's Wah'Kon-Tah and Osage-Quaker Cross-Cultural Collaboration

Article analyzes John Joseph Mathews' first book, Wah'Kon-Tah: The Osage and the White Man's Road (1932), to demonstrate its historical and biographical value as well as to show its relevance to understanding the Quaker influence that still exists in the Osage community.
Date: Winter 2010
Creator: Snyder, Michael
System: The Gateway to Oklahoma History
Die Köpfe (The Heads) (open access)

Die Köpfe (The Heads)

Front cover of the winter 2010 issue of the Hexagon, which features a sculpture of a bearded head. The inside cover includes a table of contents, a list of staff, an editorial, and a description of the cover.
Date: Winter 2010
Creator: Marshall, James L., 1940- & Marshall, Virginia R.
System: The UNT Digital Library
Mutation of WRKY transcription factors initiates pith secondary wall formation and increases stem biomass in dicotyledonous plants (open access)

Mutation of WRKY transcription factors initiates pith secondary wall formation and increases stem biomass in dicotyledonous plants

Article discussing how the mutation of WRKY transcription factors initiates pith secondary wall formation and increases stem biomass in dicotyledonous plants.
Date: December 21, 2010
Creator: Wang, Huanzhong; Avci, Utku; Nakashima, Jin; Hahn, Michael G.; Chen, Fang & Dixon, R. A.
System: The UNT Digital Library