The Effect of Government Actions on Environmental Technology Innovation: Applications to the Integrated Assessment of Carbon Sequestration Technologies (open access)

The Effect of Government Actions on Environmental Technology Innovation: Applications to the Integrated Assessment of Carbon Sequestration Technologies

This project seeks to improve the ability of integrated assessment models (IA) to incorporate changes in technology, especially environmental technologies, cost and performance over time. In this report, we present results of research that examines past experience in controlling other major power plant emissions that might serve as a reasonable guide to future rates of technological progress in carbon capture and sequestration (CCS) systems. In particular, we focus on U.S. and worldwide experience with sulfur dioxide (SO{sub 2}) and nitrogen oxide (NO{sub x}) control technologies over the past 30 years, and derive empirical learning rates for these technologies. The patterns of technology innovation are captured by our analysis of patent activities and trends of cost reduction over time. Overall, we found learning rates of 11% for the capital costs of flue gas desulfurization (FGD) system for SO{sub 2} control, and 13% for selective catalytic reduction (SCR) systems for NO{sub x} control. We explore the key factors responsible for the observed trends, especially the development of regulatory policies for SO{sub 2} and NO{sub x} control, and their implications for environmental control technology innovation.
Date: January 15, 2004
Creator: Rubin, E. S.; Hounshell, D. A.; Yeh, S.; Taylor, M.; Schrattenholzer, L.; Riahi, K. et al.
Object Type: Report
System: The UNT Digital Library
eShadow: A tool for comparing closely related sequences (open access)

eShadow: A tool for comparing closely related sequences

Primate sequence comparisons are difficult to interpret due to the high degree of sequence similarity shared between such closely related species. Recently, a novel method, phylogenetic shadowing, has been pioneered for predicting functional elements in the human genome through the analysis of multiple primate sequence alignments. We have expanded this theoretical approach to create a computational tool, eShadow, for the identification of elements under selective pressure in multiple sequence alignments of closely related genomes, such as in comparisons of human to primate or mouse to rat DNA. This tool integrates two different statistical methods and allows for the dynamic visualization of the resulting conservation profile. eShadow also includes a versatile optimization module capable of training the underlying Hidden Markov Model to differentially predict functional sequences. This module grants the tool high flexibility in the analysis of multiple sequence alignments and in comparing sequences with different divergence rates. Here, we describe the eShadow comparative tool and its potential uses for analyzing both multiple nucleotide and protein alignments to predict putative functional elements. The eShadow tool is publicly available at http://eshadow.dcode.org/
Date: January 15, 2004
Creator: Ovcharenko, Ivan; Boffelli, Dario & Loots, Gabriela G.
Object Type: Article
System: The UNT Digital Library
Isotropic-liquid crystalline phase diagram of a CdSe nanorod solution (open access)

Isotropic-liquid crystalline phase diagram of a CdSe nanorod solution

None
Date: January 15, 2004
Creator: Li, Liang-Shi; Marjanska, Malgorzata; Park, Gregory H. J.; Pines, Alexander & Alivisatos, A. Paul
Object Type: Article
System: The UNT Digital Library
Mechanism of lipid lowering in mice expressing human apolipoprotein A5 (open access)

Mechanism of lipid lowering in mice expressing human apolipoprotein A5

Recently, we reported that apoAV plays key role in triglycerides lowering. Here, we attempted to determine the mechanism underlying this hypotriglyceridemic effect. We showed that triglyceride turnover is faster in hAPOA5 transgenic compared to wild type mice. Moreover, both apoB and apoCIII are decreased and LPL activity is increased in postheparin plasma of hAPOA5 transgenic mice. These data suggest a decrease in size and number of VLDL. To further investigate the mechanism of hAPOA5 in hyperlipidemic background, we intercrossed hAPOA5 and hAPOC3 transgenic mice. The effect resulted in a marked decreased of VLDL triglyceride, cholesterol, apolipoproteins B and CIII. In postprandial state, the triglyceride response is abolished in hAPOA5 transgenic mice. We demonstrated that in response to the fat load in hAPOA5XhAPOC3 mice, apoAV shifted from HDL to VLDL, probably to limit the elevation of triglycerides. In vitro, apoAV activates lipoprotein lipase. However, apoAV does not interact with LPL but interacts physically with apoCIII. This interaction does not seem to displace apoCIII from VLDL but may induce conformational change in apoCIII and consequently change in its function leading the activation of lipoprotein lipase.
Date: January 15, 2004
Creator: Fruchart-Najib, Jamila; Bauge, Eric; Niculescu, Loredan-Stefan; Pham, Tatiana; Thomas, Benoit; Rommens, Corinne et al.
Object Type: Article
System: The UNT Digital Library
Robust Background Subtraction with Foreground Validation for Urban Traffic Video (open access)

Robust Background Subtraction with Foreground Validation for Urban Traffic Video

Identifying moving objects in a video sequence is a fundamental and critical task in many computer-vision applications. Background subtraction techniques are commonly used to separate foreground moving objects from the background. Most background subtraction techniques assume a single rate of adaptation, which is inadequate for complex scenes such as a traffic intersection where objects are moving at different and varying speeds. In this paper, we propose a foreground validation algorithm that first builds a foreground mask using a slow-adapting Kalman filter, and then validates individual foreground pixels by a simple moving object model, built using both the foreground and background statistics as well as the frame difference. Ground-truth experiments with urban traffic sequences show that our proposed algorithm significantly improves upon results using only Kalman filter or frame-differencing, and outperforms other techniques based on mixture of Gaussians, median filter, and approximated media filter.
Date: January 15, 2004
Creator: Cheung, S. S. & Kamath, C
Object Type: Article
System: The UNT Digital Library
Effect of GaN template layer strain on the growth of InxGa1-xN/GaN MQW light emitting diodes (open access)

Effect of GaN template layer strain on the growth of InxGa1-xN/GaN MQW light emitting diodes

GaN template layer strain effects were investigated on the growth of InGaN/GaN LED devices. Seven period InGaN/GaN multiple quantum well structures were deposited on 5{micro}m and 15{micro}m GaN template layers. It was found that the electroluminescence emission of the 15{micro}m device was red-shifted by approximately 132meV. Triple-axis X-Ray Diffraction and Cross-Sectional Transmission Electron Microscopy show that the 15{micro}m templay layer device was virtually unstrained while the 5{micro}m layer experienced tensile strain. Dynamic Secondary Ion Mass Spectrometry depth profiles show that the 15{micro}m template layer device had an average indium concentration of 11% higher than that of the 5{micro}m template layer device even though the structures were deposited during the same growth run. It was also found that the 15{micro}m layer device had a higher growth rate than the 5{micro}m template layer device. This difference in indium concentration and growth rate was due to changes in thermodynamic limitations caused by strain differences in the template layers.
Date: January 15, 2004
Creator: Johnson, M. C.; Bourret-Courchesne, E. D.; Wu, J.; Liliental-Weber, Z.; Zakharov, D. N.; Jorgenson, R. J. et al.
Object Type: Article
System: The UNT Digital Library
Wyoming DOE EPSCoR (open access)

Wyoming DOE EPSCoR

All of the research and human resource development projects were systemic in nature with real potential for becoming self sustaining. They concentrated on building permanent structure, such as faculty expertise, research equipment, the SEM Minority Center, and the School of Environment and Natural Resources. It was the intent of the DOE/EPSCoR project to permanently change the way Wyoming does business in energy-related research, human development for science and engineering careers, and in relationships between Wyoming industry, State Government and UW. While there is still much to be done, the DOE/EPSCoR implementation award has been successful in accomplishing that change and enhancing UW's competitiveness associated with coal utilization, electrical energy efficiency, and environmental remediation.
Date: January 15, 2004
Creator: Gern, W.A.
Object Type: Report
System: The UNT Digital Library
Sum frequency generation (SFQ) vibrational spectroscopy studies of combustion reactions on platinum single crystal surfaces (open access)

Sum frequency generation (SFQ) vibrational spectroscopy studies of combustion reactions on platinum single crystal surfaces

We have studied the dissociation of CO catalyzed by platinum single crystals. At 40 torr of CO, the Pt(111) crystal dissociates CO at 673 K. Under the same conditions, Pt(100) dissociates CO at 500 K, and Pt(557) dissociates CO at 548 K. Hence, the CO dissociation reaction is a structure sensitive reaction. SFG was used to monitor the CO top site resonance as the platinum crystals were heated to the dissociation temperature when exposed to 40 torr of CO. In all three systems, the CO resonance shifts to lower frequency as the platinum crystal is heated. However, the frequency of the CO resonance at the dissociation frequency is lower on the (100) and (111) crystal faces than on the Pt(557) crystal. We believe that the (111) and (100) crystal faces must undergo roughening to expose step or kink sites in order to facilitate the dissociation reaction. This is supported by UHV studies of CO dissociation catalyzed by platinum crystals. These studies observe dissociation only when step or kink sites are present. Since the Pt(111) surface is very stable, it needs to be heated to 673 K to produce the low coordination number sites needed for CO dissociation. Since the Pt(100) …
Date: January 15, 2004
Creator: Gaughan, Jessica S.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Cathepsin L is required for endothelial progenitor cell-induced neovascularization (open access)

Cathepsin L is required for endothelial progenitor cell-induced neovascularization

Infusion of endothelial progenitor cells (EPCs), but not of mature endothelial cells (ECs), promotes neovascularization after ischemia. We performed a gene expression profiling of EPCs and ECs to identify genes, which might be important for the neovascularization capacity of EPCs. Intriguingly, the protease cathepsin L (CathL) was highly expressed in EPCs as opposed to ECs and is essential for matrix degradation and invasion by EPCs in vitro. CathL deficient mice showed impaired functional recovery after hind limb ischemia supporting the concept for an important role of CathL in postnatal neovascularization. Infused CathL deficient progenitor cells failed to home to sites of ischemia and to augment neovascularization. In contrast, over expression of CathL in mature ECs significantly enhanced their invasive activity and induced their neovascularization capacity in vivo. Taken together, CathL plays a crucial role for the integration of circulating EPCs into the ischemic tissue and is required for neovascularization mediated by EPCs.
Date: January 15, 2004
Creator: Urbich, Carmen; Heeschen, Christopher; Aicher, Alexandra; Sasaki, Ken-ichiro; Bruhl, Thomas; Hofmann, Wolf K. et al.
Object Type: Article
System: The UNT Digital Library

Waste Package Evolution

None
Date: January 15, 2004
Creator: unknown
Object Type: Image
System: The UNT Digital Library
Benson Beach Demonstration Project: Composition and Abundance of Biota at Three Alternative Sump Sites (open access)

Benson Beach Demonstration Project: Composition and Abundance of Biota at Three Alternative Sump Sites

The Portland District of the U.S. Army Corps of Engineers is investigating plans to provide sediment to nourish beaches north of the Mouth of the Columbia River (MCR). Under the currently designed proposal, sediment dredged from the MCR will be temporarily stored at one of three proposed areas south of the North Jetty before being redredged and moved by a cutterhead pipeline dredge over the jetty to nourish Benson Beach. Resulting potential impacts to resident Dungeness crab (Cancer magister) and fishes represent one of the criteria for evaluating each of the alternative locations. To establish the species composition and relative abundance of crabs and fishes associated with each of the three proposed sump areas, researchers from the Pacific Northwest National Laboratory Marine Sciences Division completed nine field sampling trips from July 8, 2003, to November 1, 2003, for a total of 113 successful trawls comprising an area of over 7.4 ha (74,156 m2). This report documents the results of that effort. To understand the relative risk of losses to crab populations associated with dredging impacts at the sump alternative areas, it is recommended that a modified dredge impact model be developed using the data collected in this study. This model …
Date: January 15, 2004
Creator: Williams, Greg D.; Pearson, Walter H.; Evans, Nathan R. & Anderson, Michael G.
Object Type: Report
System: The UNT Digital Library
Optimal Resource Allocation in Electrical Network Defense (open access)

Optimal Resource Allocation in Electrical Network Defense

Infrastructure networks supplying electricity, natural gas, water, and other commodities are at risk of disruption due to well-engineered and coordinated terrorist attacks. Countermeasures such as hardening targets, acquisition of spare critical components, and surveillance can be undertaken to detect and deter these attacks. Allocation of available countermeasures resources to sites or activities in a manner that maximizes their effectiveness is a challenging problem. This allocation must take into account the adversary's response after the countermeasure assets are in place and consequence mitigation measures the infrastructure operation can undertake after the attack. The adversary may simply switch strategies to avoid countermeasures when executing the attack. Stockpiling spares of critical energy infrastructure components has been identified as a key element of a grid infrastructure defense strategy in a recent National Academy of Sciences report [1]. Consider a scenario where an attacker attempts to interrupt the service of an electrical network by disabling some of its facilities while a defender wants to prevent or minimize the effectiveness of any attack. The interaction between the attacker and the defender can be described in three stages: (1) The defender deploys countermeasures, (2) The attacker disrupts the network, and (3) The defender responds to the attack …
Date: January 15, 2004
Creator: Yao, Y; Edmunds, T; Papageorgiou, D & Alvarez, R
Object Type: Report
System: The UNT Digital Library
INTERNATIONAL CONFERENCE ON ULTRASHORT HIGH-ENERGY RADIATION AND MATTER (open access)

INTERNATIONAL CONFERENCE ON ULTRASHORT HIGH-ENERGY RADIATION AND MATTER

The workshop is intended as a forum to discuss the latest experimental, theoretical and computational results related to the interaction of high energy radiation with matter. High energy is intended to mean soft x-ray and beyond, but important new results from visible systems will be incorporated. The workshop will be interdisciplinary amongst scientists from many fields, including: plasma physics; x-ray physics and optics; solid state physics and material science; biology ; quantum optics. Topics will include, among other subjects: understanding damage thresholds for x-ray interactions with matter developing {approx} 5 keV x-ray sources to investigate damage; developing {approx} 100 keV Thomsom sources for material studies; developing short pulse (100 fs and less) x-ray diagnostics; developing novel X-ray optics; and developing models for the response of biological samples to ultra intense, sub ps x-rays high-energy radiation.
Date: January 15, 2004
Creator: Wootton, A J
Object Type: Report
System: The UNT Digital Library
Analytic Expressions for the Angular Resolution of Compton Gamma-ray Detectors (open access)

Analytic Expressions for the Angular Resolution of Compton Gamma-ray Detectors

This paper describes the derivation of analytic expressions for the angular resolution of reconstructing gamma rays detected via Compton interactions. We consider two types of gamma-ray detectors: Compton-ring and electron-tracking devices. In Compton-ring devices, the direction of the scattered electron is not resolved, only the total energy (electron and scattered photon) and the scattered photon direction are measured. The measured quantities define a cone about the axis of the scattered photon direction. The initial photon direction lies along this cone. Thus for single events there is a ring-like ambiguity in the photon direction. By combining multiple events, the intersection of the reconstructed rings will resolve the initial direction of the photon source. In this paper, we derive the resolution of the cone angle for individual rings. Electron-tracking type devices resolve the electron path. Although the scattered electron subsequently undergoes multiple-Coulomb scattering, it is possible to measure the initial electron direction with sufficiently high tracking resolution. By measuring the direction and energy of the electron and the direction of the scattered photon, the initial photon direction can be uniquely determined. The challenge for this type of detector is achieving the high tracking resolution. In Section 2 we derive the well-known Compton …
Date: January 15, 2004
Creator: Wright, D M
Object Type: Report
System: The UNT Digital Library
ELECTRICAL SUBSTATION RELIABILITY EVALUATION WITH EMPHASIS ON EVOLVING INTERDEPENDENCE ON COMMUNICATION INFRASTRUCTURE. (open access)

ELECTRICAL SUBSTATION RELIABILITY EVALUATION WITH EMPHASIS ON EVOLVING INTERDEPENDENCE ON COMMUNICATION INFRASTRUCTURE.

The objective of this study is to develop a methodology for a probabilistic assessment of the reliability and security of electrical energy distribution networks. This includes consideration of the future grid system, which will rely heavily on the existing digitally based communication infrastructure for monitoring and protection. Another important objective of this study is to provide information and insights from this research to Consolidated Edison Company (Con Edison) that could be useful in the design of the new network segment to be installed in the area of the World Trade Center in lower Manhattan. Our method is microscopic in nature and relies heavily on the specific design of the portion of the grid being analyzed. It extensively models the types of faults that a grid could potentially experience, the response of the grid, and the specific design of the protection schemes. We demonstrate that the existing technology can be extended and applied to the electrical grid and to the supporting communication network. A small subsection of a hypothetical grid based on the existing New York City electrical grid system of Con Edison is used to demonstrate the methods. Sensitivity studies show that in the current design the frequency for the …
Date: January 15, 2004
Creator: AZARM,M. A. BARI,R. A. MUSICKI,Z.
Object Type: Report
System: The UNT Digital Library
Assessment of Various Kinetic Models for the Pyrolysis of a Microgranular Cellulose (open access)

Assessment of Various Kinetic Models for the Pyrolysis of a Microgranular Cellulose

The kinetics of pyrolysis of a micro-crystalline cellulose in nitrogen were studied from TGA and DTG data, obtained with two different modes of heating: a dynamic mode at constant heating rates between 1 and 11 C/min and an isothermal mode at various temperatures, kept constant between 280 and 320 C. In isothermal mode, it appeared very clearly that the mass depletion shows a sigmoid profile characteristic of an auto-accelerated reaction process. This behavior is consistent with kinetics of nuclei-growth, well represented by the models of Avrami-Erofeev and of Prout-Tompkins type. All the other kinetic models commonly applied to the thermal decomposition of solids revealed unsatisfactory. The TGA and DTG data were thus found ideally simulated from a reaction scheme consisting in two parallel reactions, termed 1 and 2, each one described by the kinetic law: DX/DT = -A{sup -E/RT}x{sup n}(1-0.99x){sup n}. Reaction 1 is related to the bulk decomposition of cellulose and is characterized by the set of parameters: E{sub 1}= 202 kJ/mole; n{sub 1}=1; m{sub 1}=0.48. Reaction 2 is related to the slower residual decomposition, which takes place over approximately 350 C and affects only 16 % by weight of the raw cellulose. With m{sub 2} constrained to 1, …
Date: January 15, 2004
Creator: Burnham, A K; Capart, R & Khezami, L
Object Type: Article
System: The UNT Digital Library
Threatened and Endangered Species Evaluation for Operating Commercial Nuclear Power Generating Plants (open access)

Threatened and Endangered Species Evaluation for Operating Commercial Nuclear Power Generating Plants

The Endangered Species Act (ESA) of 1973 requires that federal agencies ensure that any action authorized, funded, or carried out under their jurisdiction is not likely to jeopardize the continued existence of any threatened or endangered (T&E) species or result in the destruction or adverse modification of critical habitats for such species. The issuance and maintenance of a federal license, such as a construction permit or operating license issued by the U.S. Nuclear Regulatory Commission (NRC) for a commercial nuclear power generating facility is a federal action under the jurisdiction of a federal agency, and is therefore subject to the provisions of the ESA. The Office of Nuclear Reactor Regulation (NRR) staff have performed appropriate assessments of potential impacts to threatened or endangered species, and consulted with appropriate agencies with regard to protection of such species in authorizing the construction, operation, and relicensing of nuclear power generating facilities. However, the assessments and consultations concerning many facilities were performed during the 1970's or early 1980's, and have not been re-evaluated in detail or updated since those initial evaluations. A review of potential Endangered Species Act issues at licensed nuclear power facilities was completed in 1997. In that review 484 different ESA-listed …
Date: January 15, 2004
Creator: Sackschewsky, Michael R.
Object Type: Report
System: The UNT Digital Library
A prospective study of XRCC1 haplotypes and their interaction with plasma carotenoids on breast cancer risk (open access)

A prospective study of XRCC1 haplotypes and their interaction with plasma carotenoids on breast cancer risk

The XRCC1 protein is involved in the base excision repair pathway through interactions with other proteins. Polymorphisms in the XRCC1 gene may lead to variation in repair proficiency and confer inherited predisposition to cancer. We prospectively assessed the associations between polymorphisms and haplotypes in XRCC1 and breast cancer risk in a nested case-control study within the Nurses' Health Study (incident cases, n 1004; controls, n 1385). We further investigated gene-environment interactions between the XRCC1 variations and plasma carotenoids on breast cancer risk. We genotyped four haplotype-tagging single nucleotide polymorphisms Arg {sup 194}Trp, C26602T, Arg{sup 399}Gln, and Gln{sup 632}Gln in the XRCC1 gene. Five common haplotypes accounted for 99% of the chromosomes in the present study population of mostly Caucasian women. We observed a marginally significant reduction in the risk of breast cancer among {sup 194}Trp carriers. As compared with no-carriers, women with at least one {sup 194}Trp allele had a multivariate odds ratio of 0.79 (95% of the confidence interval, 0.60 -1.04). The inferred haplotype harboring the {sup 194}Trp allele was more common in controls than in cases (6.6 versus 5.3%, P 0.07). We observed that the Arg {sup 194}Trp modified the inverse associations of plasma -carotene level (P, ordinal …
Date: January 15, 2004
Creator: Mohrenweiser, H W; Han, J; Hankinson, S E; De Vivo, I; Spiegelman, D; Tamimi, R M et al.
Object Type: Article
System: The UNT Digital Library
A Generalized Mass Lumping Scheme for Maxwell's Wave Equation (open access)

A Generalized Mass Lumping Scheme for Maxwell's Wave Equation

We are interested in the high order Vector Finite Element Method (VFEM) [1] solution to Maxwell's wave equation on both orthogonal and non-orthogonal meshes. This method discretizes the wave equation in the following manner, where M is the edge mass matrix and K is the edge stiffness matrix created using classical Nedelec edge elements.
Date: January 15, 2004
Creator: Fisher, A; White, D & Rodrigue, G
Object Type: Article
System: The UNT Digital Library
Initial characterization of processes of soil carbon stabilization using forest stand-level radiocarbon enrichment (open access)

Initial characterization of processes of soil carbon stabilization using forest stand-level radiocarbon enrichment

Although the rates and mechanisms of soil organic matter (SOM) stabilization are difficult to observe directly, radiocarbon has proven an effective tracer of soil C dynamics, particularly when coupled with practical fractionation schemes. To explore the rates of C cycling in temperate forest soils, we took advantage of a unique opportunity in the form of an inadvertent stand-level {sup 14}C-labeling originating from a local industrial release. A simple density fractionation scheme separated SOM into inter-aggregate particulate organic matter (free light fraction, free LF), particulate organic matter occluded within aggregates (occluded LF), and organic matter that is complexed with minerals to form a dense fraction (dense fraction, DF). Minimal agitation and density separation was used to isolate the free LF. The remaining dense sediment was subjected to physical disruption and sonication followed by density separation to separate it into occluded LF and DF. The occluded LF had higher C concentrations and C:N ratios than the free LF, and the C concentration in both light fractions was ten times that of the DF. As a result, the light fractions together accounted for less than 4% of the soil by weight, but contained 40% of the soil C in the 0-15 cm soil …
Date: January 15, 2004
Creator: Swanston, C W; Torn, M S; Hanson, P J; Southon, J R; Garten, C T; Hanlon, E M et al.
Object Type: Article
System: The UNT Digital Library
Comparison of TracePro and Micromega Models for Infrared Heated Ice Layers Inside of Hohlraums (open access)

Comparison of TracePro and Micromega Models for Infrared Heated Ice Layers Inside of Hohlraums

A reference calculation for the infrared absorption profile was settled upon to compare results using TracePro commercial raytracing software and the Micromega codes. I have rerun the TracePro model with updated parameters to better match those used in Micromega. While the general shape of the absorption curves are consistent, the fine details still differ considerably between the two software packages.
Date: January 15, 2004
Creator: Kozioziemski, B J
Object Type: Report
System: The UNT Digital Library
Noise minimization in eukaryotic gene expression (open access)

Noise minimization in eukaryotic gene expression

All organisms have elaborate mechanisms to control rates of protein production. However, protein production is also subject to stochastic fluctuations, or noise. Several recent studies in Saccharomyces cerevisiae and Escherichia coli have investigated the relationship between transcription and translation rates and stochastic fluctuations in protein levels, or more generally, how such randomness is a function of intrinsic and extrinsic factors. However, the fundamental question of whether stochasticity in protein expression is generally biologically relevant has not been addressed, and it remains unknown whether random noise in the protein production rate of most genes significantly affects the fitness of any organism. We propose that organisms should be particularly sensitive to variation in the protein levels of two classes of genes: genes whose deletion is lethal to the organism and genes that encode subunits of multiprotein complexes. Using an experimentally verified model of stochastic gene expression in S. cerevisiae, we estimate the noise in protein production for nearly every yeast gene, and confirm our prediction that the production of essential and complex-forming proteins involves lower levels of noise than does the production of most other genes. Our results support the hypothesis that noise in gene expression is a biologically important variable, is …
Date: January 15, 2004
Creator: Fraser, Hunter B.; Hirsh, Aaron E.; Giaever, Guri; Kumm, Jochen & Eisen, Michael B.
Object Type: Article
System: The UNT Digital Library
Structure, Vibrational and Electronic Spectra of Heterofullerene C48(BN)6 (open access)

Structure, Vibrational and Electronic Spectra of Heterofullerene C48(BN)6

We report the geometrical structure, vibrational, and excitation spectra of novel, fullerene - analog C{sub 48}(BN){sub 6} using density functional calculations. The lowest energy structure is one in which B-N bonding is present as boron and nitrogen occupy each of the twelve pentagons of the fullerene cage. The cluster is polar with a net dipole moment of 0.55 Debye, which indicates an enhanced tendency toward reactivity with other media. The excitation spectrum shows that the lowest transition of 1.75 eV is dipole-allowed. The optical gap of C{sub 48}(BN){sub 6} is redshifted by 1.17 eV relative to that of C{sub 60}, suggesting possible use as single-molecule fluorescent probes for various applications.
Date: January 15, 2004
Creator: Manaa, M R; Xie, R & Smith, V. H., Jr.
Object Type: Article
System: The UNT Digital Library