A New Approach in Advance Network Reservation and Provisioning for High-Performance Scientific Data Transfers (open access)

A New Approach in Advance Network Reservation and Provisioning for High-Performance Scientific Data Transfers

Scientific applications already generate many terabytes and even petabytes of data from supercomputer runs and large-scale experiments. The need for transferring data chunks of ever-increasing sizes through the network shows no sign of abating. Hence, we need high-bandwidth high speed networks such as ESnet (Energy Sciences Network). Network reservation systems, i.e. ESnet's OSCARS (On-demand Secure Circuits and Advance Reservation System) establish guaranteed bandwidth of secure virtual circuits at a certain time, for a certain bandwidth and length of time. OSCARS checks network availability and capacity for the specified period of time, and allocates requested bandwidth for that user if it is available. If the requested reservation cannot be granted, no further suggestion is returned back to the user. Further, there is no possibility from the users view-point to make an optimal choice. We report a new algorithm, where the user specifies the total volume that needs to be transferred, a maximum bandwidth that he/she can use, and a desired time period within which the transfer should be done. The algorithm can find alternate allocation possibilities, including earliest time for completion, or shortest transfer duration - leaving the choice to the user. We present a novel approach for path finding in …
Date: January 28, 2010
Creator: Balman, Mehmet; Chaniotakis, Evangelos; Shoshani, Arie & Sim, Alex
Object Type: Report
System: The UNT Digital Library
Report of Official Foreign Travel to Montreal, Canada (open access)

Report of Official Foreign Travel to Montreal, Canada

How can DOE, NNSA, and Y-12 best handle the integration of information from diverse sources, and what will best ensure that legacy data will survive changes in computing systems for the future? Although there is no simple answer, it is becoming increasingly clear throughout the information-management industry that a key component of both preservation and integration of information is the adoption of standardized data formats. The most notable standardized format is XML, to which almost all data is now migrating. XML is derived from SGML, as is HTML, the common language of the World Wide Web. XML is becoming increasingly important as part of the Y-12 data infrastructure. Y-12 is implementing a new generation of XML-based publishing systems. Y-12 already has been supporting projects at DOE Headquarters, such as the Guidance Streamlining Initiative (GSI) that will result in the storage of classification guidance in XML. Y-12 collects some test data in XML as the result of Electronic Data Capture (EDC), and XML data is also used in Engineering Releases. I am participating in a series of projects sponsored by the PRIDE initiative that include the capture of dimensional certification and other similar records in XML, the creation of XML formats …
Date: August 28, 2010
Creator: Mason, J. D.
Object Type: Report
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.
Object Type: Article
System: The UNT Digital Library
Assessment of the Use of Nitrogen Trifluoride for Purifying Coolant and Heat Transfer Salts in the Fluoride Salt-Cooled High-Temperature Reactor (open access)

Assessment of the Use of Nitrogen Trifluoride for Purifying Coolant and Heat Transfer Salts in the Fluoride Salt-Cooled High-Temperature Reactor

This report provides an assessment of the use of nitrogen trifluoride for removing oxide and water-caused contaminants in the fluoride salts that will be used as coolants in a molten salt cooled reactor.
Date: September 28, 2010
Creator: Scheele, Randall D. & Casella, Andrew M.
Object Type: Report
System: The UNT Digital Library
Study of the neutron damage on electronics at the National Ignition Facility (open access)

Study of the neutron damage on electronics at the National Ignition Facility

The NIF environment is very complex leading to a large and non trivial radiation background. A shield surrounding the electronics is required to lower the neutron background to less than 1e7 n/cm{sup 2}. Moving electronics to behind the 6 foot-thick target bay wall is the best shield.
Date: October 28, 2010
Creator: Dauffy, L S; Mcnaney, J M & Khater, H Y
Object Type: Article
System: The UNT Digital Library
Actinic imaging and evaluation of phase structures on EUV lithography masks (open access)

Actinic imaging and evaluation of phase structures on EUV lithography masks

The authors describe the implementation of a phase-retrieval algorithm to reconstruct phase and complex amplitude of structures on EUV lithography masks. Many native defects commonly found on EUV reticles are difficult to detect and review accurately because they have a strong phase component. Understanding the complex amplitude of mask features is essential for predictive modeling of defect printability and defect repair. Besides printing in a stepper, the most accurate way to characterize such defects is with actinic inspection, performed at the design, EUV wavelength. Phase defect and phase structures show a distinct through-focus behavior that enables qualitative evaluation of the object phase from two or more high-resolution intensity measurements. For the first time, phase of structures and defects on EUV masks were quantitatively reconstructed based on aerial image measurements, using a modified version of a phase-retrieval algorithm developed to test optical phase shifting reticles.
Date: September 28, 2010
Creator: Mochi, Iacopo; Goldberg, Kenneth & Huh, Sungmin
Object Type: Article
System: The UNT Digital Library
International Clean Energy Coalition (open access)

International Clean Energy Coalition

In 2003, the National Association of Regulatory Utility Commissioners (NARUC) and National Energy Technology Laboratories (NETL) collaboratively established the International Clean Energy Coalition (ICEC). The coalition consisting of energy policy-makers, technologists, and financial institutions was designed to assist developing countries in forming and supporting local approaches to greenhouse gas mitigation within the energy sector. ICEC's work focused on capacity building and clean energy deployment in countries that rely heavily on fossil-based electric generation. Under ICEC, the coalition formed a steering committee consisting of NARUC members and held a series of meetings to develop and manage the workplan and define successful outcomes for the projects. ICEC identified India as a target country for their work and completed a country assessment that helped ICEC build a framework for discussion with Indian energy decisionmakers including two follow-on in-country workshops. As of the conclusion of the project in 2010, ICEC had also conducted outreach activities conducted during United Nations Framework Convention on Climate Change (UNFCCC) Ninth Conference of Parties (COP 9) and COP 10. The broad goal of this project was to develop a coalition of decision-makers, technologists, and financial institutions to assist developing countries in implementing affordable, effective and resource appropriate technology and …
Date: September 28, 2010
Creator: Skootsky, Erin; Gardner, Matt & Flansburgh, Bevan
Object Type: Report
System: The UNT Digital Library
Physical Property Analysis and Report for Sediments at 100-BC-5 Operable Unit, Boreholes C7505, C7506, C7507, and C7665 (open access)

Physical Property Analysis and Report for Sediments at 100-BC-5 Operable Unit, Boreholes C7505, C7506, C7507, and C7665

Between October 14, 2009 and February 22, 2010 sediment samples were received from 100-BC Decision Unit for geochemical studies. This is an analytical data report for sediments received from CHPRC at the 100 BC 5 OU. The analyses for this project were performed at the 325 building located in the 300 Area of the Hanford Site. The analyses were performed according to Pacific Northwest National Laboratory (PNNL) approved procedures and/or nationally recognized test procedures. The data sets include the sample identification numbers, analytical results, estimated quantification limits (EQL), and quality control data. The preparatory and analytical quality control requirements, calibration requirements, acceptance criteria, and failure actions are defined in the on-line QA plan 'Conducting Analytical Work in Support of Regulatory Programs' (CAW). This QA plan implements the Hanford Analytical Services Quality Assurance Requirements Documents (HASQARD) for PNNL.
Date: September 28, 2010
Creator: Lindberg, Michael J.
Object Type: Report
System: The UNT Digital Library
Algorithm Summary and Evaluation: Automatic Implementation of Ringdown Analysis for Electromechanical Mode Identification from Phasor Measurements (open access)

Algorithm Summary and Evaluation: Automatic Implementation of Ringdown Analysis for Electromechanical Mode Identification from Phasor Measurements

Small signal stability problems are one of the major threats to grid stability and reliability. Prony analysis has been successfully applied on ringdown data to monitor electromechanical modes of a power system using phasor measurement unit (PMU) data. To facilitate an on-line application of mode estimation, this paper develops a recursive algorithm for implementing Prony analysis and proposed an oscillation detection method to detect ringdown data in real time. By automatically detecting ringdown data, the proposed method helps guarantee that Prony analysis is applied properly and timely on the ringdown data. Thus, the mode estimation results can be performed reliably and timely. The proposed method is tested using Monte Carlo simulations based on a 17-machine model and is shown to be able to properly identify the oscillation data for on-line application of Prony analysis. In addition, the proposed method is applied to field measurement data from WECC to show the performance of the proposed algorithm.
Date: February 28, 2010
Creator: Zhou, Ning; Huang, Zhenyu; Tuffner, Francis K.; Jin, Shuangshuang; Lin, Jenglung & Hauer, Matthew L.
Object Type: Report
System: The UNT Digital Library
Efficient Windows Collaborative: Research Tool Dissemination to Increase Energy Efficient Fenestration Product Penetration (open access)

Efficient Windows Collaborative: Research Tool Dissemination to Increase Energy Efficient Fenestration Product Penetration

The project goals covered both the residential and commercial windows markets and involved a range of audiences such as window manufacturers, builders, homeowners, design professionals, utilities, and public agencies. Essential goals included: (1) Creation of 'Master Toolkits' of information that integrate diverse tools, rating systems, and incentive programs, customized for key audiences such as window manufacturers, design professionals, and utility programs. (2) Delivery of education and outreach programs to multiple audiences through conference presentations, publication of articles for builders and other industry professionals, and targeted dissemination of efficient window curricula to professionals and students. (3) Design and implementation of mechanisms to encourage and track sales of more efficient products through the existing Window Products Database as an incentive for manufacturers to improve products and participate in programs such as NFRC and ENERGY STAR. (4) Development of utility incentive programs to promote more efficient residential and commercial windows. Partnership with regional and local entities on the development of programs and customized information to move the market toward the highest performing products. An overarching project goal was to ensure that different audiences adopt and use the developed information, design and promotion tools and thus increase the market penetration of energy efficient fenestration …
Date: February 28, 2010
Creator: Alliance to Save Energy (U.S.)
Object Type: Report
System: The UNT Digital Library
Evolution of organic aerosol mass spectra upon heating: implications for OA phase and partitioning behavior (open access)

Evolution of organic aerosol mass spectra upon heating: implications for OA phase and partitioning behavior

Vacuum Ultraviolet (VUV) photoionization mass spectrometry has been used to measure the evolution of chemical composition for two distinct organic aerosol types as they are passed through a thermodenuder at different temperatures. The two organic aerosol types considered are primary lubricating oil (LO) aerosol and secondary aerosol from the alpha-pinene + O3 reaction (alphaP). The evolution of the VUV mass spectra for the two aerosol types with temperature are observed to differ dramatically. For LO particles, the spectra exhibit distinct changes with temperature in which the lower m/z peaks, corresponding to compounds with higher vapor pressures, disappear more rapidly than the high m/z peaks. In contrast, the alphaP aerosol spectrum is essentially unchanged by temperature even though the particles experience significant mass loss due to evaporation. The variations in the LO spectra are found to be quantitatively in agreement with expectations from absorptive partitioning theory whereas the alphaP spectra suggest that the evaporation of alphaP derived aerosol appears to not be governed by partitioning theory. We postulate that this difference arises from the alphaP particles existing as in a glassy state instead of having the expected liquid-like behavior. To reconcile these observations with decades of aerosol growth measurements, which indicate …
Date: October 28, 2010
Creator: Davis, UC; Cappa, Christopher D. & Wilson, Kevin R.
Object Type: Article
System: The UNT Digital Library
Field Summary Report for Remedial Investigation of Hanford Site Releases to the Columbia River, Hanford Site, Washington (open access)

Field Summary Report for Remedial Investigation of Hanford Site Releases to the Columbia River, Hanford Site, Washington

This report documents field activity associated with the collection, preparation, and shipment of fish samples. The purpose of the report is to describe the sampling locations, identify samples collected, and describe any modifications and additions made to the sampling and analysis plan.
Date: September 28, 2010
Creator: Hulstrom, L. C.
Object Type: Report
System: The UNT Digital Library
TECHNICAL COMPARISON OF CANDIDATE ION EXCHANGE MEDIA FOR SMALL COLUMN ION EXCHANGE (SCIX) APPLICATIONS IN SUPPORT OF SUPPLEMENTAL LAW PRETREATMENT (open access)

TECHNICAL COMPARISON OF CANDIDATE ION EXCHANGE MEDIA FOR SMALL COLUMN ION EXCHANGE (SCIX) APPLICATIONS IN SUPPORT OF SUPPLEMENTAL LAW PRETREATMENT

At-tank supplemental pretreatment including both filtration and small column ion exchange is currently under evaluation to facilitate salt waste retrieval and processing in the Hanford tank farms. Spherical resorcinol formaldehyde (sRF) resin is the baseline ion exchange resin for use in the Waste Treatment and Immobilization Plant (WTP). This document provides background and technical rationale to assist in determining whether spherical resorcinol formaldehyde (sRF) is also the appropriate ion exchange resin for supplemental LAW pretreatment processes and compares sRF with crystalline silicotitanate (CST) as potential supplemental pretreatment ion exchange media.
Date: December 28, 2010
Creator: AA, RAMSEY & MR, THORSON
Object Type: Report
System: The UNT Digital Library
WASTE LOADING ENHANCEMENTS FOR HANFORD LAW GLASSES VLS-10R1790-1 FINAL REPORT REV 0 12/1/2010 (open access)

WASTE LOADING ENHANCEMENTS FOR HANFORD LAW GLASSES VLS-10R1790-1 FINAL REPORT REV 0 12/1/2010

About 50 million gallons of high-level mixed waste is currently stored in underground tanks at The United States Department of Energy's (DOE's) Hanford site in the State of Washington. The Hanford Tank Waste Treatment and Immobilization Plant (WTP) will provide DOE's Office of River Protection (ORP) with a means of treating this waste by vitrification for subsequent disposal. The tank waste will be separated into low- and high-activity waste fractions, which will then be vitrified respectively into Immobilized Low Activity Waste (ILAW) and Immobilized High Level Waste (IHLW) products. The ILAW product will be disposed in an engineered facility on the Hanford site while the IHLW product will likely be directed to a national deep geological disposal facility for high-level nuclear waste. The ILAW and IHLW products must meet a variety of requirements with respect to protection of the environment before they can be accepted for disposal. The Office of River Protection is currently examining options to optimize the Low Activity Waste (LAW) Facility and LAW glass waste form. One option under evaluation is to enhance the waste processing rate of the vitrification plant currently under construction. It is likely that the capacity of the LAW vitrification plant can be …
Date: December 28, 2010
Creator: Kruger, A. A.; Muller, I. S.; Joseph, I.; Matlack, K. S.; Gan, H. & Pegg, I. L.
Object Type: Report
System: The UNT Digital Library
SLUDGE BATCH 6/TANK 51 SIMULANT CHEMICAL PROCESS CELL SIMULATIONS (open access)

SLUDGE BATCH 6/TANK 51 SIMULANT CHEMICAL PROCESS CELL SIMULATIONS

Qualification simulant testing was completed to determine appropriate processing conditions and assumptions for the Sludge Batch 6 (SB6) Shielded Cells demonstration of the DWPF flowsheet using the qualification sample from Tank 51 for SB6 after SRNL washing. It was found that an acid addition window of 105-139% of the DWPF acid equation (100-133% of the Koopman minimum acid equation) gave acceptable Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) results for nitrite destruction and hydrogen generation. Hydrogen generation occurred continuously after acid addition in three of the four tests. The three runs at 117%, 133%, and 150% stoichiometry (Koopman) were all still producing around 0.1 lb hydrogen/hr at DWPF scale after 42 hours of boiling in the SRAT. The 150% acid run reached 110% of the DWPF SRAT limit of 0.65 lb H{sub 2}/hr, and the 133% acid run reached 75% of the DWPF SME limit of 0.223 lb H{sub 2}/hr. Conversely, nitrous oxide generation was subdued compared to previous sludge batches, staying below 25 lb/hr in all four tests or about a fourth as much as in comparable SB4 testing. Two other processing issues were noted. First, incomplete mercury suspension impacted mercury stripping from the SRAT …
Date: April 28, 2010
Creator: Koopman, David & Best, David
Object Type: Report
System: The UNT Digital Library
Maltose Biochemistry and Transport in Plant Leaves (open access)

Maltose Biochemistry and Transport in Plant Leaves

Final Technical Report for DOE grant DE-FG02-04ER15565 Maltose Biochemistry and Transport in Plant Leaves PI Thomas D. Sharkey University of Wisconsin-Madison Starch is a desirable plant product for both food and biofuel. Leaf starch is ideal for use in biofuels because it does not compete with grain starch, which is used for food. Starch is accumulated in plant leaves during the day and broken down at night. If we can manipulate leaf starch breakdown it may be possible to design a plant that provides both grain starch for food and leaf starch for biofuel. The pathway of leaf starch breakdown was not known when this work started. Preliminary evidence had shown that maltose was the primary product of leaf starch breakdown (Weise, Weber & Sharkey, 2004) and that it was metabolized by a disproportionating enzyme called amylomaltase but given the initials DPE2 (Lu & Sharkey, 2004). In this work we showed that only one form of maltose was metabolically active (Weise et al., 2005a) and that maltose was located in two different places when the amylomaltase was knocked out but only inside the chloroplast when the maltose transporter was knocked out (Lu et al., 2006a). This allowed us to estimate …
Date: January 28, 2010
Creator: Sharkey, Thomas D.
Object Type: Report
System: The UNT Digital Library
ARM Climate Research Facility Instrumentation Status and Information January 2010 (open access)

ARM Climate Research Facility Instrumentation Status and Information January 2010

The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.
Date: February 28, 2010
Creator: Voyles, J. W.
Object Type: Report
System: The UNT Digital Library
YALINA Facility a Sub-Critical Accelerator- Driven System (Ads) for Nuclear Energy Research Facility Description and an Overview of the Research Program (1997-2008). (open access)

YALINA Facility a Sub-Critical Accelerator- Driven System (Ads) for Nuclear Energy Research Facility Description and an Overview of the Research Program (1997-2008).

The YALINA facility is a zero-power, sub-critical assembly driven by a conventional neutron generator. It was conceived, constructed, and put into operation at the Radiation Physics and Chemistry Problems Institute of the National Academy of Sciences of Belarus located in Minsk-Sosny, Belarus. This facility was conceived for the purpose of investigating the static and dynamic neutronics properties of accelerator driven sub-critical systems, and to serve as a neutron source for investigating the properties of nuclear reactions, in particular transmutation reactions involving minor-actinide nuclei. This report provides a detailed description of this facility and documents the progress of research carried out there during a period of approximately a decade since the facility was conceived and built until the end of 2008. During its history of development and operation to date (1997-2008), the YALINA facility has hosted several foreign groups that worked with the resident staff as collaborators. The participation of Argonne National Laboratory in the YALINA research programs commenced in 2005. For obvious reasons, special emphasis is placed in this report on the work at YALINA facility that has involved Argonne's participation. Attention is given here to the experimental program at YALINA facility as well as to analytical investigations aimed at …
Date: April 28, 2010
Creator: Gohar, Y. & Smith, D. L.
Object Type: Report
System: The UNT Digital Library
Quantum Phase Extraction in Isospectral Electronic Nanostructures (open access)

Quantum Phase Extraction in Isospectral Electronic Nanostructures

Quantum phase is not a direct observable and is usually determined by interferometric methods. We present a method to map complete electron wave functions, including internal quantum phase information, from measured single-state probability densities. We harness the mathematical discovery of drum-like manifolds bearing different shapes but identical resonances, and construct quantum isospectral nanostructures possessing matching electronic structure but divergent physical structure. Quantum measurement (scanning tunneling microscopy) of these 'quantum drums' [degenerate two-dimensional electron states on the Cu(111) surface confined by individually positioned CO molecules] reveals that isospectrality provides an extra topological degree of freedom enabling robust quantum state transplantation and phase extraction.
Date: April 28, 2010
Creator: Moon, Christopher
Object Type: Article
System: The UNT Digital Library
AN EXPERIMENTAL STUDY OF THE STABILITY OF VESSEL-SPANNING BUBBLES IN CYLINDRICAL & ANNULAR & OBROUND & AND CONICAL CONTAINERS (open access)

AN EXPERIMENTAL STUDY OF THE STABILITY OF VESSEL-SPANNING BUBBLES IN CYLINDRICAL & ANNULAR & OBROUND & AND CONICAL CONTAINERS

This report provides a summary of experiments that were performed by Fauske & Associates on the stability of vessel-spanning bubbles. The report by Fauske & Associates, An Experimental Study of the Stability of Vessel-Spanning Bubbles in Cylindrical, Annular, Obround and Conical Containers, is included in Appendix A. Results from the experiments confirm that the gravity yield parameter, Y{sub G}, correctly includes container size and can be applied to full-scale containers to predict the possibility of the formation of a stable vessel spanning bubble. The results also indicate that a vessel spanning bubble will likely form inside the STSC for KE, KW, and Settler sludges if the shear strengths of these sludges exceed 1820, 2080, and 2120 Pa, respectively. A passive mechanism installed in the STSC is effective at disrupting a rising sludge plug and preventing the sludge from plugging the vent filter or being forced out of the container. The Sludge Treatment Project for Engineered Container and Settler Sludge (EC/ST) Disposition Subproject is being conducted in two phases. Phase 1 of the EC/ST Disposition Subproject will retrieve the radioactive sludge currently stored in the K West (KW) Basin into Sludge Transport and Storage Containers (STSCs) and transport the STSCs to …
Date: January 28, 2010
Creator: TK, DHALIWAL
Object Type: Report
System: The UNT Digital Library
CHARACTERIZATION OF CORE SAMPLE COLLECTED FROM THE SALTSTONE DISPOSAL FACILITY (open access)

CHARACTERIZATION OF CORE SAMPLE COLLECTED FROM THE SALTSTONE DISPOSAL FACILITY

During the month of September 2008, grout core samples were collected from the Saltstone Disposal Facility, Vault 4, cell E. This grout was placed during processing campaigns in December 2007 from Deliquification, Dissolution and Adjustment Batch 2 salt solution. The 4QCY07 Waste Acceptance Criteria sample collected on 11/16/07 represents the salt solution in the core samples. Core samples were retrieved to initiate the historical database of properties of emplaced Saltstone and to demonstrate the correlation between field collected and laboratory prepared samples. Three samples were collected from three different locations. Samples were collected using a two-inch diameter concrete coring bit. In April 2009, the core samples were removed from the evacuated sample container, inspected, transferred to PVC containers, and backfilled with nitrogen. Samples furthest from the wall were the most intact cylindrically shaped cored samples. The shade of the core samples darkened as the depth of coring increased. Based on the visual inspection, sample 3-3 was selected for all subsequent analysis. The density and porosity of the Vault 4 core sample, 1.90 g/cm{sup 3} and 59.90% respectively, were comparable to values achieved for laboratory prepared samples. X-ray diffraction analysis identified phases consistent with the expectations for hydrated Saltstone. Microscopic analysis …
Date: January 28, 2010
Creator: Cozzi, A. & Duncan, A.
Object Type: Report
System: The UNT Digital Library
SLUDGE BATCH 6/TANK 40 SIMULANT CHEMICAL PROCESS CELL SIMULATIONS (open access)

SLUDGE BATCH 6/TANK 40 SIMULANT CHEMICAL PROCESS CELL SIMULATIONS

None
Date: April 28, 2010
Creator: Koopman, David
Object Type: Report
System: The UNT Digital Library
Quantum Detection and Invisibility in Coherent Nanostructures (open access)

Quantum Detection and Invisibility in Coherent Nanostructures

We address quantum invisibility in the context of electronics in nanoscale quantum structures. In analogy with metamaterials, we use the freedom of design that quantum corrals provide and show that quantum mechanical objects can be hidden inside the corral, with respect to inelastic electron scattering spectroscopy in combination with scanning tunneling microscopy, and we propose a design strategy. A simple illustration of the invisibility is given in terms of an elliptic quantum corral containing a molecule, with a local vibrational mode, at one of the foci. Our work has implications to quantum information technology and presents new tools for nonlocal quantum detection and distinguishing between different molecules.
Date: April 28, 2010
Creator: Fransson, J.
Object Type: Article
System: The UNT Digital Library
Non-diffusive spin dynamics in a two-dimensional electron gas (open access)

Non-diffusive spin dynamics in a two-dimensional electron gas

We describe measurements of spin dynamics in the two-dimensional electron gas in GaAs/GaAlAs quantum wells. Optical techniques, including transient spin-grating spectroscopy, are used to probe the relaxation rates of spin polarization waves in the wavevector range from zero to 6 x 10{sup 4} cm{sup -1}. We find that the spin polarization lifetime is maximal at nonzero wavevector, in contrast with expectation based on ordinary spin diffusion, but in quantitative agreement with recent theories that treat diffusion in the presence of spin-orbit coupling.
Date: April 28, 2010
Creator: Weber, C.P.
Object Type: Article
System: The UNT Digital Library