An Assessment of Molecular Dynamic Force Fields for Silica for Use in Simulating Laser Damage Mitigation (open access)

An Assessment of Molecular Dynamic Force Fields for Silica for Use in Simulating Laser Damage Mitigation

We compare force fields (FF's) that have been used in molecular dynamic (MD) simulations of silica in order to assess their applicability for use in simulating IR-laser damage mitigation. Although pairwise FF?s obtained by fitting quantum mechanical calculations such as the BKS and CHIK potentials have been shown to reproduce many of the properties of silica including the stability of silica polymorphs and the densification of the liquid, we show that melting temperatures and fictive temperatures are much too high. Softer empirical force fields give liquid and glass properties at experimental temperatures but may not predict all properties important to laser mitigation experiments.
Date: October 21, 2010
Creator: Soules, T F; Gilmer, G H; Matthews, M J; Stolken, J S & Feit, M D
System: The UNT Digital Library
Still Processing Tons of Data with QuickView (open access)

Still Processing Tons of Data with QuickView

This slide show is about data analysis for photonic Doppler velocimetry.
Date: October 21, 2012
Creator: Diaz, A. B.
System: The UNT Digital Library
Ionic Liquids: Radiation Chemistry, Solvation Dynamics and Reactivity Patterns (open access)

Ionic Liquids: Radiation Chemistry, Solvation Dynamics and Reactivity Patterns

N/A
Date: October 21, 2012
Creator: F., Wishart J.
System: The UNT Digital Library
Illumina Unamplified Indexed Library Construction: An Automated Approach (open access)

Illumina Unamplified Indexed Library Construction: An Automated Approach

Manual library construction is a limiting factor in Illumina sequencing. Constructing libraries by hand is costly, time-consuming, low-throughput, and ergonomically hazardous, and constructing multiple libraries introduces risk of library failure due to pipetting errors. The ability to construct multiple libraries simultaneously in automated fashion represents significant cost and time savings. Here we present a strategy to construct up to 96 unamplified indexed libraries using Illumina TruSeq reagents and a Biomek FX robotic platform. We also present data to indicate that this library construction method has little or no risk of cross-contamination between samples.
Date: March 21, 2011
Creator: Hack, Christopher A.; Sczyrba, Alexander & Cheng, Jan-Fang
System: The UNT Digital Library
Bridging silyl groups in sigma-bond metathesis and [1, 2] shifts. An experimental and computational study of the reaction between cerium metallocenes and MeOSiMe3 (open access)

Bridging silyl groups in sigma-bond metathesis and [1, 2] shifts. An experimental and computational study of the reaction between cerium metallocenes and MeOSiMe3

The reaction of Cp'2CeH (Cp' = 1,2,4-(Me3C)3C5H2 ) with MeOSiMe3 gives Cp'2CeOMe and HSiMe3 and the reaction of the metallacycle, Cp'[(Me3C)2C5H2C(Me) 2CH2]Ce, with MeOSiMe3 yields Cp'2CeOCH2SiMe3, formed from hypothetical Cp'2CeCH2OSiMe3 by a [1, 2] shift also known as a silyl-Wittig rearrangement. Although both cerium products are alkoxides, they are formed by different pathways. DFT calculations on the reaction of the model metallocene, Cp2CeH, and MeOSiMe3 show that the lowest energy pathway is a H for OMe exchange at Ce that occurs by way of a sigma-bond metathesis transition state as SiMe3 exchanges partners. The formation of Cp2CeOCH2SiMe3 occurs by way of a low activation barrier [1, 2]shift of the SiMe3 group in Cp2CeCH2OSiMe3. Calculations on a model metallacycle, Cp[C5H4C(Me)2CH2]Ce, show that the metallacycle favors CH bond activation over sigma-bond metathesis involving the transfer of the SiMe3 group in good agreement with experiment. The sigma-bond metathesis involving the transfer of SiMe3 and the [1, 2]shift of SiMe3 reactions have in common a pentacoordinate silicon at the transition states. A molecular orbital analysis illustrates the connection between these two Si-O bond cleavage reactions and traces the reason why they occur for a silyl but not for an alkyl group to the difference …
Date: April 21, 2010
Creator: Werkema, Evan; Yahia, Ahmed; Maron, Laurent; Eisenstein, Odile & Andersen, Richard
System: The UNT Digital Library
The status of open heavy flavor production at RHIC (open access)

The status of open heavy flavor production at RHIC

We discuss the calculation of open heavy flavor cross sections at RHIC and describe how the semileptonic decays of charm and bottom quarks can be separated.
Date: December 21, 2010
Creator: Vogt, R
System: The UNT Digital Library
CO and CO2 Hydrogenation to Methanol Calculated Using the BEEF-vdW Functional (open access)

CO and CO2 Hydrogenation to Methanol Calculated Using the BEEF-vdW Functional

None
Date: February 21, 2013
Creator: Studt, Felix; Abild-Pedersen, Frank; Varley, Joel B. & Norskov, Jens K.
System: The UNT Digital Library
Constraining Dark Matter in Galactic Substructure (open access)

Constraining Dark Matter in Galactic Substructure

In this paper we discuss detection prospects by combining two different aspects of the gamma-ray signal: the angular distribution and the photon counts probability distribution function (PDF).
Date: June 21, 2013
Creator: Baxter, Eric J.; Dodelson, Scott; Koushiappas, Savvas M. & Strigari, Louis E.
System: The UNT Digital Library
Systematic Scale-Setting to All Orders: The Principle of Maximum Conformality and Commensurate Scale Relations (open access)

Systematic Scale-Setting to All Orders: The Principle of Maximum Conformality and Commensurate Scale Relations

None
Date: January 21, 2014
Creator: Brodsky, Stanley J.; Mojaza, Matin & Wu, Xing-Gang
System: The UNT Digital Library
Compact, Inexpensive, Safe, and Rapidly Refuelable Hydrogen Storage in Cryogenic Pressure Vessels (open access)

Compact, Inexpensive, Safe, and Rapidly Refuelable Hydrogen Storage in Cryogenic Pressure Vessels

None
Date: September 21, 2012
Creator: Aceves, S. M.; Petitpas, G.; Espinosa-Loza, F.; Matthews, M. J. & Ledesma-Orozco, E.
System: The UNT Digital Library
DUAL Gamma-Ray Mission (open access)

DUAL Gamma-Ray Mission

None
Date: June 21, 2013
Creator: Boggs, S.; Wunderer, C.; von Ballmoos, P.; Takahashi, T.; Gehrels, N.; Tueller, J. et al.
System: The UNT Digital Library
GROUNDWATER MONITORING REPORT GENERATION TOOLS - 12005 (open access)

GROUNDWATER MONITORING REPORT GENERATION TOOLS - 12005

Compliance with National and State environmental regulations (e.g. Resource Conservation and Recovery Act (RCRA) and Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) aka SuperFund) requires Savannah River Site (SRS) to extensively collect and report groundwater monitoring data, with potential fines for missed reporting deadlines. Several utilities have been developed at SRS to facilitate production of the regulatory reports which include maps, data tables, charts and statistics. Components of each report are generated in accordance with complex sets of regulatory requirements specific to each site monitored. SRS developed a relational database to incorporate the detailed reporting rules with the groundwater data, and created a set of automation tools to interface with the information and generate the report components. These process improvements enhanced quality and consistency by centralizing the information, and have reduced manpower and production time through automated efficiencies.
Date: November 21, 2011
Creator: Lopez, N.
System: The UNT Digital Library
Ancient nature of alternative splicing and functions of introns (open access)

Ancient nature of alternative splicing and functions of introns

Using four genomes: Chamydomonas reinhardtii, Agaricus bisporus, Aspergillus carbonarius, and Sporotricum thermophile with EST coverage of 2.9x, 8.9x, 29.5x, and 46.3x respectively, we identified 11 alternative splicing (AS) types that were dominated by intron retention (RI; biased toward short introns) and found 15, 35, 52, and 63percent AS of multiexon genes respectively. Genes with AS were more ancient, and number of AS correlated with number of exons, expression level, and maximum intron length of the gene. Introns with tendency to be retained had either stop codons or length of 3n+1 or 3n+2 presumably triggering nonsense-mediated mRNA decay (NMD), but introns retained in major isoforms (0.2-6percent of all introns) were biased toward 3n length and stop codon free. Stopless introns were biased toward phase 0, but 3n introns favored phase 1 that introduced more flexible and hydrophilic amino acids on both ends of introns which would be less disruptive to protein structure. We proposed a model in which minor RI intron could evolve into major RI that could facilitate intron loss through exonization.
Date: March 21, 2011
Creator: Zhou, Kemin; Salamov, Asaf; Kuo, Alan; Aerts, Andrea & Grigoriev, Igor
System: The UNT Digital Library
DAFNE Setup And Operation With the Crab-Waist Collision Scheme (open access)

DAFNE Setup And Operation With the Crab-Waist Collision Scheme

In the second half of 2007 a major upgrade has been implemented on the Frascati DA{Phi}NE collider in order to test the novel idea of Crab-Waist collisions. New vacuum chambers and permanent quadrupole magnets have been designed, built and installed to realize the new configuration. At the same time the performances of relevant hardware components, such as fast injection kickers and shielded bellows have been improved relying on new design concepts. The collider has been successfully commissioned in this new configuration. The paper describes several experimental results about linear and non-linear optics setup and optimization, damping of beam-beam instabilities and discusses the obtained luminosity performances. DA{Phi}NE [1] is the Frascati lepton collider working at the c m. energy of the {Phi} meson resonance (1020). It came in operation in 2001 and till summer 2007 provided luminosity, in sequence, to three different experiments which logged a total integrated luminosity of {approx} 4.4 fb{sup -1}. During these years the collider reached its best performances in terms of luminosity and background (L{sub peak} = 1.6 x 10{sup 32} cm{sup -2}s{sup -1} L{sub day} {approx} 10 pb{sup -1}) by means of several successive upgrades, relying on the experience gathered during the collider operations and …
Date: October 21, 2011
Creator: Milardi, C.; Alesini, D.; Biagini, M. E.; Biscari, C.; Boni, R.; Boscolo, M. et al.
System: The UNT Digital Library
2011 RENEWABLE ENERGY: SOLAR FUELS GORDON RESEARCH CONFERENCE (open access)

2011 RENEWABLE ENERGY: SOLAR FUELS GORDON RESEARCH CONFERENCE

The conference will present and discuss current science that underlies solar fuels production, and will focus on direct production pathways for production. Thus, recent advances in design and understanding of molecular systems and materials for light capture and conversion of relevance for solar fuels will be discussed. An important set of topics will be homogeneous, heterogeneous and biological catalysts for the multi-electron processes of water oxidation, hydrogen production and carbon dioxide reduction to useful fuels. Also, progress towards integrated and scalable systems will be presented. Attached is a copy of the formal schedule and speaker program and the poster program.
Date: January 21, 2011
Creator: Hupp, Joseph
System: The UNT Digital Library
Simplified models for mask roughness induced LER (open access)

Simplified models for mask roughness induced LER

The ITRS requires < 1.2nm line-edge roughness (LER) for the 22nm half-pitch node. Currently, we can consistently achieve only about 3nm LER. Further progress requires understanding the principle causes of LER. Much work has already been done on how both the resist and LER on the mask effect the final printed LER. What is poorly understood, however, is the extent to which system-level effects such as mask surface roughness, illumination conditions, and defocus couple to speckle at the image plane, and factor into LER limits. Presently, mask-roughness induced LER is studied via full 2D aerial image modeling and subsequent analysis of the resulting image. This method is time consuming and cumbersome. It is, therefore, the goal of this research to develop a useful 'rule-of-thumb' analytic model for mask roughness induced LER to expedite learning and understanding.
Date: February 21, 2011
Creator: McClinton, Brittany & Naulleau, Patrick
System: The UNT Digital Library
Development of an ASIC for Dual Mirror Telescopes of the Cherenkov Telescope Array (open access)

Development of an ASIC for Dual Mirror Telescopes of the Cherenkov Telescope Array

None
Date: September 21, 2012
Creator: Martinez, Manel; Vandenbroucke, Justin; Bechtol, Keith; Funk, Stefan; Okumura, Akira; Tajima, Hiro et al.
System: The UNT Digital Library
Gravitationally Consistent HALO Catalogs and Merger Trees for Precision Cosmology (open access)

Gravitationally Consistent HALO Catalogs and Merger Trees for Precision Cosmology

Presents a new algorithm for generating merger trees and halo catologs.
Date: December 21, 2012
Creator: Behroozi, Peter S.; Wechsler, Risa H.; Wu, Hao-Yi; Busha, Michael T.; Klypin, Anatoly A. & Primack, Joel R.
System: The UNT Digital Library
Polarization in SuperB (open access)

Polarization in SuperB

SuperB, the 2nd-generation B-Factory with a luminosity of 10{sup 36}/cm{sup 2}/s proposed for LNF, is being designed from the start to be capable of providing a spin-polarized electron beam in the low-energy ring (LER) with longitudinal polarization at the interaction point. Due to the high luminosity at moderate beam current the beam lifetime is short (a few minutes), and a polarized injector will be used. Spin rotators have been designed and the equilibrium polarization evaluated. It will be shown that an average polarization of about 70% can be expected.
Date: June 21, 2012
Creator: Wienands, Ulrich; /SLAC; Nosochkov, Yuri; /SLAC; Sullivan, Michael; /SLAC et al.
System: The UNT Digital Library
Mapping Diffuse Seismicity Using Empirical Matched Field Processing Techniques (open access)

Mapping Diffuse Seismicity Using Empirical Matched Field Processing Techniques

The objective of this project is to detect and locate more microearthquakes using the empirical matched field processing (MFP) method than can be detected using only conventional earthquake detection techniques. We propose that empirical MFP can complement existing catalogs and techniques. We test our method on continuous seismic data collected at the Salton Sea Geothermal Field during November 2009 and January 2010. In the Southern California Earthquake Data Center (SCEDC) earthquake catalog, 619 events were identified in our study area during this time frame and our MFP technique identified 1094 events. Therefore, we believe that the empirical MFP method combined with conventional methods significantly improves the network detection ability in an efficient matter.
Date: January 21, 2011
Creator: Wang, J; Templeton, D C & Harris, D B
System: The UNT Digital Library
Quantitative evaluation of mask phase defects from through-focus EUV aerial images (open access)

Quantitative evaluation of mask phase defects from through-focus EUV aerial images

Mask defects inspection and imaging is one of the most important issues for any pattern transfer lithography technology. This is especially true for EUV lithography where the wavelength-specific properties of masks and defects necessitate actinic inspection for a faithful prediction of defect printability and repair performance. In this paper we will present a technique to obtain a quantitative characterization of mask phase defects from EUV aerial images. We apply this technique to measure the aerial image phase of native defects on a blank mask, measured with the SEMATECH Berkeley Actinic Inspection Tool (AIT) an EUV zoneplate microscope that operates at Lawrence Berkeley National Laboratory. The measured phase is compared with predictions made from AFM top-surface measurements of those defects. While amplitude defects are usually easy to recognize and quantify with standard inspection techniques like scanning electron microscopy (SEM), defects or structures that have a phase component can be much more challenging to inspect. A phase defect can originate from the substrate or from any level of the multilayer. In both cases its effect on the reflected field is not directly related to the local topography of the mask surface, but depends on the deformation of the multilayer structure. Using the …
Date: February 21, 2011
Creator: Mochi, Iacopo; Yamazoe, Kenji; Neureuther, Andrew & Goldberg, Kenneth A.
System: The UNT Digital Library
Absorber height effects on SWA restrictions and 'Shadow' LER (open access)

Absorber height effects on SWA restrictions and 'Shadow' LER

As extreme-ultraviolet lithography (EUVL) approaches introduction at the 22-nm half-pitch node, several key aspects of absorber height effects remain unexplored. In particular, sidewall angle (SWA) restrictions based on the height of the mask absorber has not yet been clearly defined. In addition, the effects of absorber height on line-edge roughness (LER) from shadowing has not been examined. We make an initial investigation into how tight SWA constraints are and the extent to which shadow LER alters basic LER. Our approach to SWA aims to find SWA restrictions based on 10% of the total CD error budget (10% of CD). Thus, we allot the SWA budget a {+-}0.2nm tolerance for 22nm half-pitch. New with EUVL is the off-axis illumination system. One potential pitfall that must be carefully monitored is the effect of mask absorber height blocking light from reaching, and therefore, correctly detecting, the base edge position of a feature. While mask features can correctly compensate sizing to target at the wafer, the effects of this shadowing on LER have not yet been investigated. Specifically, shadow LER may exacerbate or mitigate the inherent LER on the mask. Shadowing may also cause a difference in the observed LER on the right and …
Date: February 21, 2011
Creator: McClinton, Brittany & Naulleau, Patrick
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
Time-Resolved Synchrotron X-ray Diffraction on Pulse Laser Heated Iron in Diamond Anvil Cell (open access)

Time-Resolved Synchrotron X-ray Diffraction on Pulse Laser Heated Iron in Diamond Anvil Cell

The authors present time-resolved synchrotron x-ray diffraction to probe the {var_epsilon}-{delta} phase transition of iron during pulse-laser heating in a diamond anvil cell. The system utilizes a monochromatic synchrotron x-ray beam, a two-dimensional pixel array x-ray detector and a dual beam, double side laser-heating system. Multiple frames of the diffraction images are obtained in real-time every 22 ms over 500 ms of the entire pulse heating period. The results show the structural evolution of iron phases at 17 GPa, resulting in thermal expansion coefficient 1/V({Delta}V/{Delta}T){sub p} = 7.1 * 10{sup -6}/K for {var_epsilon}-Fe and 2.4 * 10{sup -5}/K for {gamma}-Fe, as well as the evidence for metastability of {gamma}-Fe at low temperatures below the {var_epsilon}-{gamma} phase boundary.
Date: September 21, 2011
Creator: Yoo, C. S.; Wei, H.; Dias, R.; Shen, G.; Smith, J.; Chen, J. Y. et al.
System: The UNT Digital Library