Moment-of-fluid analytic reconstruction on 2D Cartesian grids
NASA Astrophysics Data System (ADS)
Lemoine, Antoine; Glockner, Stéphane; Breil, Jérôme
2017-01-01
Moment-of-Fluid (MoF) is a piecewise linear interface reconstruction method that tracks fluid through its volume fraction and centroid, which are deduced from the zeroth and first moments. We present a method that replaces the original minimization stage by an analytic reconstruction algorithm on bi-dimensional Cartesian grids. This algorithm provides accurate results for a lower computational cost than the original minimization algorithm. When more than two fluids are involved, this algorithm can be used coupled with the minimization algorithm. Although this paper deals with Cartesian grids, everything remains valid for any meshes that are made of rectangular cells.
Adaptive 2-D wavelet transform based on the lifting scheme with preserved vanishing moments.
Vrankic, Miroslav; Sersic, Damir; Sucic, Victor
2010-08-01
In this paper, we propose novel adaptive wavelet filter bank structures based on the lifting scheme. The filter banks are nonseparable, based on quincunx sampling, with their properties being pixel-wise adapted according to the local image features. Despite being adaptive, the filter banks retain a desirable number of primal and dual vanishing moments. The adaptation is introduced in the predict stage of the filter bank with an adaptation region chosen independently for each pixel, based on the intersection of confidence intervals (ICI) rule. The image denoising results are presented for both synthetic and real-world images. It is shown that the obtained wavelet decompositions perform well, especially for synthetic images that contain periodic patterns, for which the proposed method outperforms the state of the art in image denoising.
Analysis of Highly-Resolved Simulations of 2-D Humps Toward Improvement of Second-Moment Closures
NASA Technical Reports Server (NTRS)
Jeyapaul, Elbert; Rumsey Christopher
2013-01-01
Fully resolved simulation data of flow separation over 2-D humps has been used to analyze the modeling terms in second-moment closures of the Reynolds-averaged Navier- Stokes equations. Existing models for the pressure-strain and dissipation terms have been analyzed using a priori calculations. All pressure-strain models are incorrect in the high-strain region near separation, although a better match is observed downstream, well into the separated-flow region. Near-wall inhomogeneity causes pressure-strain models to predict incorrect signs for the normal components close to the wall. In a posteriori computations, full Reynolds stress and explicit algebraic Reynolds stress models predict the separation point with varying degrees of success. However, as with one- and two-equation models, the separation bubble size is invariably over-predicted.
NASA Astrophysics Data System (ADS)
Xie, Bin; Deng, Xi; Sun, Ziyao; Xiao, Feng
2017-04-01
We propose a novel Mach-uniform numerical model for 2D Euler equations on unstructured grids by using multi-moment finite volume method. The model integrates two key components newly developed to solve compressible flows on unstructured grids with improved accuracy and robustness. A new variant of AUSM scheme, so-called AUSM+-pcp (AUSM+ with pressure-correction projection), has been devised including a pressure-correction projection to the AUSM+ flux splitting, which maintains the exact numerical conservativeness and works well for all Mach numbers. A novel 3th-order, non-oscillatory and less-dissipative reconstruction has been proposed by introducing a multi-dimensional limiting and a BVD (boundary variation diminishing) treatment to the VPM (volume integrated average (VIA) and point value (PV) based multi-moment) reconstruction. The resulting reconstruction scheme, the limited VPM-BVD formulation, is able to resolve both smooth and non-smooth solutions with high fidelity. Benchmark tests have been used to verify the present model. The numerical results substantiate the present model as an accurate and robust unstructured-grid formulation for flows of all Mach numbers.
NASA Astrophysics Data System (ADS)
Sahoo, B. K.; Aoki, T.; Das, B. P.; Sakemi, Y.
2016-03-01
Employing the relativistic coupled-cluster method, comparative studies of the parity nonconserving electric dipole amplitudes for the 7 s 1/2 2S →6 d 5/2 2D transitions in 210Fr and 211Fr isotopes have been carried out. It is found that these transition amplitudes, sensitive only to the nuclear spin-dependent effects, are enhanced substantially owing to the very large contributions from the electron core-polarization effects in Fr. This translates to a relatively large and, in principle, measurable induced light shift, which would be a signature of nuclear spin-dependent parity nonconservation that is dominated by the nuclear anapole moment in a heavy atom like Fr. A plausible scheme to measure this quantity using the Cyclotron and Radioisotope Center (CYRIC) facility at Tohoku University has been outlined.
Improved Quick Disconnect (QD) Interface Through Fail Safe Parts Identification
NASA Technical Reports Server (NTRS)
Blanch-Payne, Evelyn
2001-01-01
An extensive review of existing Quick Disconnects (QDs) mating and demating operations was performed to determine which shuttle part interface identifications and procedures contribute to human factor errors. The research methods used consisted of interviews with engineers and technicians, examination of incident reports, critiques of video and audio tapes of QD operations, and attendance of a Hyper QD operational course. The data strongly suggests that there are inherit human factor errors involved in QD operations. To promote fail-safe operations, QD interface problem areas and recommendations were outlined and reviewed. It is suggested that dialogue, investigations and recommendations continue.
Radiative efficiency of MOCVD grown QD lasers
NASA Astrophysics Data System (ADS)
Mawst, Luke; Tsvid, Gene; Dudley, Peter; Kirch, Jeremy; Park, J. H.; Kim, N.
2010-02-01
The optical spectral gain characteristics and overall radiative efficiency of MOCVD grown InGaAs quantum dot lasers have been evaluated. Single-pass, multi-segmented amplified spontaneous emission measurements are used to obtain the gain, absorption, and spontaneous emission spectra in real units. Integration of the calibrated spontaneous emission spectra then allows for determining the overall radiative efficiency, which gives important insights into the role which nonradiative recombination plays in the active region under study. We use single pass, multi-segmented edge-emitting in which electrically isolated segments allow to vary the length of a pumped region. In this study we used 8 section devices (the size of a segment is 50x300 μm) with only the first 5 segments used for varying the pump length. The remaining unpumped segments and scribed back facet minimize round trip feedback. Measured gain spectra for different pump currents allow for extraction of the peak gain vs. current density, which is fitted to a logarithmic dependence and directly compared to conventional cavity length analysis, (CLA). The extracted spontaneous emission spectrum is calibrated and integrated over all frequencies and modes to obtain total spontaneous radiation current density and radiative efficiency, ηr. We find ηr values of approximately 17% at RT for 5 stack QD active regions. By contrast, high performance InGaAs QW lasers exhibit ηr ~50% at RT.
Effective Medium Approach for Planar QD Structures
2001-06-01
condition (EBC) method is extended to nano- scale planar meso- scopic systems. The EBCs appear as a result of the 2D-homogenization procedure and have...intrinsic spatial inhomogeneity. Since the inho- mogeneity scale is much less than the optical wavelength, QDs can be treated as electrically small objects...Real parts of these poles determine resonant frequencies while imaginary parts • ve the homogeneous linewidths. It can easily be shown that EBCs
Nadtochiy, A. M.; Mintairov, S. A.; Kalyuzhnyy, N. A.; Rouvimov, S. S.; Shernyakov, Yu. M.; Payusov, A. S.; Maximov, M. V.; Zhukov, A. E.
2015-08-15
Heterostructures with InGaAs quantum dots (QDs) are synthesized on vicinal GaAs (001) substrates. The photoluminescence (PL) spectra and threshold characteristics of edge-emitting QD lasers are studied in the temperature range 10-400 K. The structural properties of QDs are examined by transmission electron microscopy. Analysis of the PL spectra demonstrates the bimodality of the QD array, which leads to an unusual temperature behavior of the PL spectra and threshold current density. A model of the population of a bimodal QD array by carriers, describing the observed phenomena, is considered.
Improved QD-BRET conjugates for detection and imaging
Xing, Yun; So, Min-kyung; Koh, Ai-leen; Sinclair, Robert; Rao, Jianghong
2008-01-01
Self-illuminating quantum dots, also known as QD-BRET conjugates, are a new class of quantum dots bioconjugates which do not need external light for excitation. Instead, light emission relies on the bioluminescence resonance energy transfer from the attached Renilla luciferase enzyme, which emits light upon the oxidation of its substrate. QD-BRET combines the advantages of the QDs (such as superior brightness & photostability, tunable emission, multiplexing) as well as the high sensitivity of bioluminescence imaging, thus holds the promise for improved deep tissue in vivo imaging. Although studies have demonstrated the superior sensitivity and deep tissue imaging potential, the stability of the QD-BRET conjugates in biological environment needs to be improved for long-term imaging studies such as in vivo cell trafficking. In this study, we seek to improve the stability of QD-BRET probes through polymeric encapsulation with a polyacrylamide gel. Results show that encapsulation caused some activity loss, but significantly improved both the in vitro serum stability and in vivo stability when subcutaneously injected into the animal. Stable QD-BRET probes should further facilitate their applications for both in vitro testing as well as in vivo cell tracking studies. PMID:18468518
Improved QD-BRET conjugates for detection and imaging
Xing Yun; So, Min-kyung; Koh, Ai Leen; Sinclair, Robert; Rao Jianghong
2008-08-01
Self-illuminating quantum dots, also known as QD-BRET conjugates, are a new class of quantum dot bioconjugates which do not need external light for excitation. Instead, light emission relies on the bioluminescence resonance energy transfer from the attached Renilla luciferase enzyme, which emits light upon the oxidation of its substrate. QD-BRET combines the advantages of the QDs (such as superior brightness and photostability, tunable emission, multiplexing) as well as the high sensitivity of bioluminescence imaging, thus holding the promise for improved deep tissue in vivo imaging. Although studies have demonstrated the superior sensitivity and deep tissue imaging potential, the stability of the QD-BRET conjugates in biological environment needs to be improved for long-term imaging studies such as in vivo cell tracking. In this study, we seek to improve the stability of QD-BRET probes through polymeric encapsulation with a polyacrylamide gel. Results show that encapsulation caused some activity loss, but significantly improved both the in vitro serum stability and in vivo stability when subcutaneously injected into the animal. Stable QD-BRET probes should further facilitate their applications for both in vitro testing as well as in vivo cell tracking studies.
Photoinduced hole transfer in QD-phthalocyanine hybrids.
Arvani, M; Virkki, K; Abou-Chahine, F; Efimov, A; Schramm, A; Tkachenko, N V; Lupo, D
2016-10-05
A series of CdSe quantum dot (QD)-phthalocyanine (Pc) hybrids were synthesized and their photophysics was studied using steady state and time-resolved spectroscopic methods. Emission of QDs was progressively quenched upon increasing the concentration of Pc in the hybrids. A detailed transient absorption study of the hybrids revealed that the mechanism of quenching is charge separation, resulting in the formation of hybrids with negatively charged QDs and the Pc cation. Direct photo-excitation of Pc did not show any detectable interaction between the excited state of Pc and the QD to which it is attached. An explanation is proposed, based on the suggestion that the energy of the lowest unoccupied molecular orbital (LUMO) of Pc is lower than the lower edge of the QD conduction band, while the energy of the highest occupied molecular orbital (HOMO) of Pc is sufficiently higher than the high energy edge of the QD valence band (VB), thus permitting hole transfer from the QD VB to the Pc HOMO after photo-excitation of QDs.
QD-Based FRET Probes at a Glance
Shamirian, Armen; Ghai, Aashima; Snee, Preston T.
2015-01-01
The unique optoelectronic properties of quantum dots (QDs) give them significant advantages over traditional organic dyes, not only as fluorescent labels for bioimaging, but also as emissive sensing probes. QD sensors that function via manipulation of fluorescent resonance energy transfer (FRET) are of special interest due to the multiple response mechanisms that may be utilized, which in turn imparts enhanced flexibility in their design. They may also function as ratiometric, or “color-changing” probes. In this review, we describe the fundamentals of FRET and provide examples of QD-FRET sensors as grouped by their response mechanisms such as link cleavage and structural rearrangement. An overview of early works, recent advances, and various models of QD-FRET sensors for the measurement of pH and oxygen, as well as the presence of metal ions and proteins such as enzymes, are also provided. PMID:26053750
Computing Q-D Relationships for Storage of Rocket Fuels
NASA Technical Reports Server (NTRS)
Jester, Keith
2005-01-01
The Quantity Distance Measurement Tool is a GIS BASEP computer program that aids safety engineers by calculating quantity-distance (Q-D) relationships for vessels that contain explosive chemicals used in testing rocket engines. (Q-D relationships are standard relationships between specified quantities of specified explosive materials and minimum distances by which they must be separated from persons, objects, and other explosives to obtain specified types and degrees of protection.) The program uses customized geographic-information-system (GIS) software and calculates Q-D relationships in accordance with NASA's Safety Standard For Explosives, Propellants, and Pyrotechnics. Displays generated by the program enable the identification of hazards, showing the relationships of propellant-storage-vessel safety buffers to inhabited facilities and public roads. Current Q-D information is calculated and maintained in graphical form for all vessels that contain propellants or other chemicals, the explosiveness of which is expressed in TNT equivalents [amounts of trinitrotoluene (TNT) having equivalent explosive effects]. The program is useful in the acquisition, siting, construction, and/or modification of storage vessels and other facilities in the development of an improved test-facility safety program.
ERIC Educational Resources Information Center
Williams, Kate
2012-01-01
The informatics moment is the moment when a person seeks help in using some digital technology that is new to him or her. This article examines the informatics moment in people's everyday lives as they sought help at a branch public library. Four types of literacy were involved: basic literacy (reading and writing), computer literacy (use of a…
NASA Astrophysics Data System (ADS)
Lotsch, Bettina V.
2015-07-01
Graphene's legacy has become an integral part of today's condensed matter science and has equipped a whole generation of scientists with an armory of concepts and techniques that open up new perspectives for the postgraphene area. In particular, the judicious combination of 2D building blocks into vertical heterostructures has recently been identified as a promising route to rationally engineer complex multilayer systems and artificial solids with intriguing properties. The present review highlights recent developments in the rapidly emerging field of 2D nanoarchitectonics from a materials chemistry perspective, with a focus on the types of heterostructures available, their assembly strategies, and their emerging properties. This overview is intended to bridge the gap between two major—yet largely disjunct—developments in 2D heterostructures, which are firmly rooted in solid-state chemistry or physics. Although the underlying types of heterostructures differ with respect to their dimensions, layer alignment, and interfacial quality, there is common ground, and future synergies between the various assembly strategies are to be expected.
2D semiconductor optoelectronics
NASA Astrophysics Data System (ADS)
Novoselov, Kostya
The advent of graphene and related 2D materials has recently led to a new technology: heterostructures based on these atomically thin crystals. The paradigm proved itself extremely versatile and led to rapid demonstration of tunnelling diodes with negative differential resistance, tunnelling transistors, photovoltaic devices, etc. By taking the complexity and functionality of such van der Waals heterostructures to the next level we introduce quantum wells engineered with one atomic plane precision. Light emission from such quantum wells, quantum dots and polaritonic effects will be discussed.
NASA Astrophysics Data System (ADS)
Hospodková, Alice; Vyskočil, Jan; Zíková, Markéta; Oswald, Jiří; Pangrác, Jiří; Petříček, Otto
2017-02-01
Type-II band alignment offers several advantages for proposed intermediate band solar cell structures. We focused on the quantum dot (QD) solar cell structures based on type-II InAs/GaAs QD layers capped with GaAsSb strain reducing layers. The GaAsSb strain reducing layers were prepared with or without graded Sb concentration. Strong enhancement of photocurrent was achieved by adding an InGaAs buffer layer under the type-II QD structure, thanks to improved electron extraction from QDs. For comparison, a structure with GaAs-capped InAs QDs was prepared, too. Properties of all structures are compared and the mechanism of carrier extraction or relaxation is discussed. Gradient of antimony concentration in a strain reducing layer (SRL) significantly improved resulting properties of solar cell structures. It is shown that in a multiple-QD structure with a GaAsSb SRL, electrons and holes have non-intersecting trajectories which prevents carrier recombination and improves the efficiency of solar cell structures. NextNano band structure calculations of different types of structures support our experimental results.
GaIn As Quantum Dots (QD) grown by Liquid Phase Epitaxy (LPE)
NASA Astrophysics Data System (ADS)
Ortiz Vázquez, F. E.; Mishurnyi, V. A.; Gorbatchev, A. Yu.; DeAnda, F.; Elyukhin, V. A.
2009-05-01
The majority of the semiconductor structures with QD today are grown by MBE and MOCVD. It is known that the best material quality can be achieved by LPE because, in contrast to MBE and MOCVD, this method is realized at near-equilibrium conditions. To develop QD LPE technology first of all it is necessary to find out a growth technique allowing the crystallization of epitaxial materials with very small volume. This can be done by means of different techniques. In this work we apply a low temperature short-time growth method, which allows the production not only of single, but also of multilayer heterostructures. We have grown GaxIn1-zAs QD on GaAs (100) substrates at 450 C. The details of the QD formation, depending on composition of the GaxIn-x As solid solutions, have been studied by atom-force microscopy. The photoluminescence spectra of investigated samples show, in addition to a short-wave GaAs related peak, a longer wavelength line, which disappears after removal of the grown GaInAs material using an etching solution. This fact, together with atom-force microscopy results can be interpreted as a proof that QD heterostructures were grown successfully by LPE.
Size effect on the electronic and optical band gap of CdSe QD
Sisodia, Namita
2014-04-24
Present paper deals with a critical and comprehensive analysis of the dependence of photo emission (PE) electronic band gap and optical absorption (OA) excitonic band gap on the size of CdSe QD, via connecting it with excitonic absorbance wavelength. Excitonic absorbance wavelength is determined through an empirical fit of established experimental evidences. Effective excitonic charge and Bohr radius is determined as a function of size. Increase in size of the CdSe QD results in greater Bohr radius and smaller effective excitonic charge. Excitonic binding energy as a degree of size of QD is also calculated which further relates with the difference in PE electronic and OA optical band gaps. It is also shown that with increase in size of CdSe QD, the excitonic binding energy decreases which consequently increases differences in two band gaps. Our results are very well comparable with the established results. Explanation for the origin of the unusual optical properties of CdSe QD has been also discussed.
Tunable microwave signal generator with an optically-injected 1310 nm QD-DFB laser.
Hurtado, Antonio; Mee, Jesse; Nami, Mohsen; Henning, Ian D; Adams, Michael J; Lester, Luke F
2013-05-06
Tunable microwave signal generation with frequencies ranging from below 1 GHz to values over 40 GHz is demonstrated experimentally with a 1310 nm Quantum Dot (QD) Distributed-Feedback (DFB) laser. Microwave signal generation is achieved using the period 1 dynamics induced in the QD DFB under optical injection. Continuous tuning in the positive detuning frequency range of the quantum dot's unique stability map is demonstrated. The simplicity of the experimental configuration offers promise for novel uses of these nanostructure lasers in Radio-over-Fiber (RoF) applications and future mobile networks.
E-2D Advanced Hawkeye Aircraft (E-2D AHE)
2015-12-01
Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-364 E-2D Advanced Hawkeye Aircraft (E-2D AHE) As of FY 2017 President’s Budget Defense...Office Estimate RDT&E - Research, Development, Test, and Evaluation SAR - Selected Acquisition Report SCP - Service Cost Position TBD - To Be Determined
Growth and properties of AIIIBV QD structures for intermediate band solar cells
NASA Astrophysics Data System (ADS)
Vyskočil, J.; Gladkov, P.; Petříček, O.; Hospodková, A.; Pangrác, J.
2015-03-01
Intermediate band solar cells theoretically offer a promising way to significantly increase cell efficiency compared to a single-junction solar cell. We focused on the preparation of antimony containing materials as a covering of QD layers. In this article we discuss how the concentration gradient of GaAsSb strain reducing layers can influence the resulting optical properties of the solar cell structures. The main principle of the structure is that the absorption of light is achieved at QD excited states with a better overlap of electron and hole wave functions. With fast relaxation of carriers to the ground state, the electrons and holes are quickly spatially separated. Two different composition gradients of GaAsSb SRL were used for the solar cell structure. One or five quantum dot stacks were compared. The maximal PC increased approximately 17 times with increasing number of QD layers from 1 to 5. The highest PC was achieved for sample I5A with increasing concentration of Sb in the SRL, especially in the QD absorption region. The possible explanation is a better carrier separation in this type of structure suppressing the radiative recombination rate in QDs. These results suggest a high application potential of this structure for photovoltaics.
Au/SiO2/QD core/shell/shell nanostructures with plasmonic-enhanced photoluminescence
NASA Astrophysics Data System (ADS)
Yang, Ping; Kawasaki, Kazunori; Ando, Masanori; Murase, Norio
2012-09-01
A sol-gel method has been developed to fabricate Au/SiO2/quantum dot (QD) core-shell-shell nanostructures with plasmonic-enhanced photoluminescence (PL). Au nanoparticle (NP) was homogeneously coated with a SiO2 shell with adjusted thickness through a Stöber synthesis. When the toluene solution of hydrophobic CdSe/ZnS QDs was mixed with partially hydrolyzed 3-aminopropyltrimethoxysilane (APS) sol, the ligands on the QDs were replaced by a thin functional SiO2 layer because the amino group in partially hydrolyzed APS has strong binding interaction with the QDs. Partially hydrolyzed APS plays an important role as a thin functional layer for the transfers of QDs to water phase and the subsequent connection to aqueous SiO2-coated Au NPs. Although Au NPs were demonstrated as efficient PL quenchers when the SiO2 shell on the Au NPs is thin (less than 5 nm), we found that precise control of the spacing between the Au NP core and the QD shell resulted in QDs with an enhancement of 30 % of PL efficiency. The Au/SiO2/QD core/shell/shell nanostructures also reveal strong surface plasmon scattering, which makes the Au/SiO/QD core-shell-shell nanostructures an excellent dual-modality imaging probe. This technology can serve as a general route for encapsulating a variety of discrete nanomaterials because monodispersed nanostructures often have a similar surface chemistry.
Al-Jamal, Wafa' T; Al-Jamal, Khuloud T; Cakebread, Andrew; Halket, John M; Kostarelos, Kostas
2009-09-01
The present work describes the pharmacokinetics of recently developed liposome-quantum dot (L-QD) hybrid vesicles in nude mice following systemic administration. Hydrophobic QD were incorporated into different bilayer compositions, and the serum stability of such hybrid vesicles was evaluated using turbidity and carboxyfluorescein release measurements. L-QD hybrid blood profile and organ biodistribution were also determined by elemental (cadmium) analysis. Following intravenous administration, different tissue biodistribution profiles and tissue affinities were observed depending on the L-QD lipid bilayer characteristics. Immediate blood clearance was observed with cationic (DOTAP/DOPE/Chol) hybrid with rapid lung accumulation, while incorporation of PEG at the surface of zwitterionic vesicles dramatically prolonged their blood circulation half-life after systemic administration. Overall, the L-QD hybrid vesicle system is considered a viable platform that allows QD delivery to different tissues through facile modulation of the hybrid vesicle characteristics. In addition, L-QD offers many opportunities for the development of combinatory therapeutic and imaging (theranostic) modalities by incorporating both drug molecules and QD within the different compartments of a single vesicle.
2-D or not 2-D, that is the question: A Northern California test
Mayeda, K; Malagnini, L; Phillips, W S; Walter, W R; Dreger, D
2005-06-06
Reliable estimates of the seismic source spectrum are necessary for accurate magnitude, yield, and energy estimation. In particular, how seismic radiated energy scales with increasing earthquake size has been the focus of recent debate within the community and has direct implications on earthquake source physics studies as well as hazard mitigation. The 1-D coda methodology of Mayeda et al. has provided the lowest variance estimate of the source spectrum when compared against traditional approaches that use direct S-waves, thus making it ideal for networks that have sparse station distribution. The 1-D coda methodology has been mostly confined to regions of approximately uniform complexity. For larger, more geophysically complicated regions, 2-D path corrections may be required. The complicated tectonics of the northern California region coupled with high quality broadband seismic data provides for an ideal ''apples-to-apples'' test of 1-D and 2-D path assumptions on direct waves and their coda. Using the same station and event distribution, we compared 1-D and 2-D path corrections and observed the following results: (1) 1-D coda results reduced the amplitude variance relative to direct S-waves by roughly a factor of 8 (800%); (2) Applying a 2-D correction to the coda resulted in up to 40% variance reduction from the 1-D coda results; (3) 2-D direct S-wave results, though better than 1-D direct waves, were significantly worse than the 1-D coda. We found that coda-based moment-rate source spectra derived from the 2-D approach were essentially identical to those from the 1-D approach for frequencies less than {approx}0.7-Hz, however for the high frequencies (0.7{le} f {le} 8.0-Hz), the 2-D approach resulted in inter-station scatter that was generally 10-30% smaller. For complex regions where data are plentiful, a 2-D approach can significantly improve upon the simple 1-D assumption. In regions where only 1-D coda correction is available it is still preferable over 2
Acousto-Optic Processing of 2-D Signals Using Temporal and Spatial Integration.
1983-05-31
Documents includes data on: Architectures; Coherence Properties of Pulsed Laser Diodes; Acousto - optic device data; Dynamic Range Issues; Image correlation; Synthetic aperture radar; 2-D Fourier transform; and Moments.
Optoelectronics with 2D semiconductors
NASA Astrophysics Data System (ADS)
Mueller, Thomas
2015-03-01
Two-dimensional (2D) atomic crystals, such as graphene and layered transition-metal dichalcogenides, are currently receiving a lot of attention for applications in electronics and optoelectronics. In this talk, I will review our research activities on electrically driven light emission, photovoltaic energy conversion and photodetection in 2D semiconductors. In particular, WSe2 monolayer p-n junctions formed by electrostatic doping using a pair of split gate electrodes, type-II heterojunctions based on MoS2/WSe2 and MoS2/phosphorene van der Waals stacks, 2D multi-junction solar cells, and 3D/2D semiconductor interfaces will be presented. Upon optical illumination, conversion of light into electrical energy occurs in these devices. If an electrical current is driven, efficient electroluminescence is obtained. I will present measurements of the electrical characteristics, the optical properties, and the gate voltage dependence of the device response. In the second part of my talk, I will discuss photoconductivity studies of MoS2 field-effect transistors. We identify photovoltaic and photoconductive effects, which both show strong photoconductive gain. A model will be presented that reproduces our experimental findings, such as the dependence on optical power and gate voltage. We envision that the efficient photon conversion and light emission, combined with the advantages of 2D semiconductors, such as flexibility, high mechanical stability and low costs of production, could lead to new optoelectronic technologies.
Highly crystalline 2D superconductors
NASA Astrophysics Data System (ADS)
Saito, Yu; Nojima, Tsutomu; Iwasa, Yoshihiro
2016-12-01
Recent advances in materials fabrication have enabled the manufacturing of ordered 2D electron systems, such as heterogeneous interfaces, atomic layers grown by molecular beam epitaxy, exfoliated thin flakes and field-effect devices. These 2D electron systems are highly crystalline, and some of them, despite their single-layer thickness, exhibit a sheet resistance more than an order of magnitude lower than that of conventional amorphous or granular thin films. In this Review, we explore recent developments in the field of highly crystalline 2D superconductors and highlight the unprecedented physical properties of these systems. In particular, we explore the quantum metallic state (or possible metallic ground state), the quantum Griffiths phase observed in out-of-plane magnetic fields and the superconducting state maintained in anomalously large in-plane magnetic fields. These phenomena are examined in the context of weakened disorder and/or broken spatial inversion symmetry. We conclude with a discussion of how these unconventional properties make highly crystalline 2D systems promising platforms for the exploration of new quantum physics and high-temperature superconductors.
Sevrin, A.
1993-06-01
After reviewing some aspects of gravity in two dimensions, I show that non-trivial embeddings of sl(2) in a semi-simple (super) Lie algebra give rise to a very large class of extensions of 2D gravity. The induced action is constructed as a gauged WZW model and an exact expression for the effective action is given.
PLAN2D - A PROGRAM FOR ELASTO-PLASTIC ANALYSIS OF PLANAR FRAMES
NASA Technical Reports Server (NTRS)
Lawrence, C.
1994-01-01
PLAN2D is a FORTRAN computer program for the plastic analysis of planar rigid frame structures. Given a structure and loading pattern as input, PLAN2D calculates the ultimate load that the structure can sustain before collapse. Element moments and plastic hinge rotations are calculated for the ultimate load. The location of hinges required for a collapse mechanism to form are also determined. The program proceeds in an iterative series of linear elastic analyses. After each iteration the resulting elastic moments in each member are compared to the reserve plastic moment capacity of that member. The member or members that have moments closest to their reserve capacity will determine the minimum load factor and the site where the next hinge is to be inserted. Next, hinges are inserted and the structural stiffness matrix is reformulated. This cycle is repeated until the structure becomes unstable. At this point the ultimate collapse load is calculated by accumulating the minimum load factor from each previous iteration and multiplying them by the original input loads. PLAN2D is based on the program STAN, originally written by Dr. E.L. Wilson at U.C. Berkeley. PLAN2D has several limitations: 1) Although PLAN2D will detect unloading of hinges it does not contain the capability to remove hinges; 2) PLAN2D does not allow the user to input different positive and negative moment capacities and 3) PLAN2D does not consider the interaction between axial and plastic moment capacity. Axial yielding and buckling is ignored as is the reduction in moment capacity due to axial load. PLAN2D is written in FORTRAN and is machine independent. It has been tested on an IBM PC and a DEC MicroVAX. The program was developed in 1988.
Kabuss, Julia; Carmele, A.; Richter, M.; Chow, Weng W.; Knorr, A.
2011-01-10
This paper presents an inductive method for the microscopic description of quantum dot (QD) QED. Our description reproduces known effects up to an arbitrary accuracy, and is extendable to typical semiconductor effects, like many electron- and phonon-interactions. As an application, this method is used to theoretically examine quantum coherence phenomena and their impact on photon statistics for a Λ-type semiconductor QD strongly coupled to a single mode cavity and simultaneously excited with an external laser.
Metal halide solid-state surface treatment for high efficiency PbS and PbSe QD solar cells.
Crisp, Ryan W; Kroupa, Daniel M; Marshall, Ashley R; Miller, Elisa M; Zhang, Jianbing; Beard, Matthew C; Luther, Joseph M
2015-04-24
We developed a layer-by-layer method of preparing PbE (E = S or Se) quantum dot (QD) solar cells using metal halide (PbI2, PbCl2, CdI2, or CdCl2) salts dissolved in dimethylformamide to displace oleate surface ligands and form conductive QD solids. The resulting QD solids have a significant reduction in the carbon content compared to films treated with thiols and organic halides. We find that the PbI2 treatment is the most successful in removing alkyl surface ligands and also replaces most surface bound Cl(-) with I(-). The treatment protocol results in PbS QD films exhibiting a deeper work function and band positions than other ligand exchanges reported previously. The method developed here produces solar cells that perform well even at film thicknesses approaching a micron, indicating improved carrier transport in the QD films. We demonstrate QD solar cells based on PbI2 with power conversion efficiencies above 7%.
Metal Halide Solid-State Surface Treatment for High Efficiency PbS and PbSe QD Solar Cells
Crisp, R. W.; Kroupa, D. M.; Marshall, A. R.; Miller, E. M.; Zhang, J.; Beard, M. C.; Luther, J. M.
2015-04-24
We developed a layer-by-layer method of preparing PbE (E = S or Se) quantum dot (QD) solar cells using metal halide (PbI_{2}, PbCl_{2}, CdI_{2}, or CdCl_{2}) salts dissolved in dimethylformamide to displace oleate surface ligands and form conductive QD solids. The resulting QD solids have a significant reduction in the carbon content compared to films treated with thiols and organic halides. We find that the PbI_{2} treatment is the most successful in removing alkyl surface ligands and also replaces most surface bound Cl- with I-. The treatment protocol results in PbS QD films exhibiting a deeper work function and band positions than other ligand exchanges reported previously. The method developed here produces solar cells that perform well even at film thicknesses approaching a micron, indicating improved carrier transport in the QD films. We demonstrate QD solar cells based on PbI_{2} with power conversion efficiencies above 7%.
Metal Halide Solid-State Surface Treatment for High Efficiency PbS and PbSe QD Solar Cells
Crisp, R. W.; Kroupa, D. M.; Marshall, A. R.; ...
2015-04-24
We developed a layer-by-layer method of preparing PbE (E = S or Se) quantum dot (QD) solar cells using metal halide (PbI2, PbCl2, CdI2, or CdCl2) salts dissolved in dimethylformamide to displace oleate surface ligands and form conductive QD solids. The resulting QD solids have a significant reduction in the carbon content compared to films treated with thiols and organic halides. We find that the PbI2 treatment is the most successful in removing alkyl surface ligands and also replaces most surface bound Cl- with I-. The treatment protocol results in PbS QD films exhibiting a deeper work function and bandmore » positions than other ligand exchanges reported previously. The method developed here produces solar cells that perform well even at film thicknesses approaching a micron, indicating improved carrier transport in the QD films. We demonstrate QD solar cells based on PbI2 with power conversion efficiencies above 7%.« less
Moment-to-Moment Emotions during Reading
ERIC Educational Resources Information Center
Graesser, Arthur C.; D'Mello, Sidney
2012-01-01
Moment-to-moment emotions are affective states that dynamically change during reading and potentially influence comprehension. Researchers have recently identified these emotions and the emotion trajectories in reading, tutoring, and problem solving. The primary learning-centered emotions are boredom, frustration, confusion, flow (engagement),…
Shi, Chuan-Guo; Shan, Xia; Pan, Zhong-Qin; Xu, Jing-Juan; Lu, Chang; Bao, Ning; Gu, Hai-Ying
2012-03-20
Stable and sensitive electrochemiluminescence (ECL) detection relies on successful immobilization of quantum dots (QDs) on working electrodes. Herein, we report a new technique to apply double-sided carbon adhesive tape as the working electrode to improve the stability and reproducibility of QD-based ECL emission. CdS QD-modified electrodes were prepared by dropping and drying CdS QD suspension on the carbon adhesive tape supported by indium tin oxide (ITO) glass. The ECL detection was performed with the prepared electrode on a paper-based platform. We tested our system using H(2)O(2) of various concentrations and demonstrated that consistent ECL emission could be obtained. We attribute stable and reproducible ECL emission to the robust attachment of CdS QDs on the carbon adhesive tape. The proposed method could be used to quantify the concentration of dopamine from 1 μM to 10 mM based on the quenching effect of dopamine on ECL emission of CdS QD system using H(2)O(2) as the coreactant. Our approach addressed the problem in the integration of stable QD-based ECL detection with portable paper-based analytical devices. The similar design offers great potential for low-cost electrochemical and ECL analytical instruments.
2D quasiperiodic plasmonic crystals
Bauer, Christina; Kobiela, Georg; Giessen, Harald
2012-01-01
Nanophotonic structures with irregular symmetry, such as quasiperiodic plasmonic crystals, have gained an increasing amount of attention, in particular as potential candidates to enhance the absorption of solar cells in an angular insensitive fashion. To examine the photonic bandstructure of such systems that determines their optical properties, it is necessary to measure and model normal and oblique light interaction with plasmonic crystals. We determine the different propagation vectors and consider the interaction of all possible waveguide modes and particle plasmons in a 2D metallic photonic quasicrystal, in conjunction with the dispersion relations of a slab waveguide. Using a Fano model, we calculate the optical properties for normal and inclined light incidence. Comparing measurements of a quasiperiodic lattice to the modelled spectra for angle of incidence variation in both azimuthal and polar direction of the sample gives excellent agreement and confirms the predictive power of our model. PMID:23209871
NASA Astrophysics Data System (ADS)
Schaibley, John R.; Yu, Hongyi; Clark, Genevieve; Rivera, Pasqual; Ross, Jason S.; Seyler, Kyle L.; Yao, Wang; Xu, Xiaodong
2016-11-01
Semiconductor technology is currently based on the manipulation of electronic charge; however, electrons have additional degrees of freedom, such as spin and valley, that can be used to encode and process information. Over the past several decades, there has been significant progress in manipulating electron spin for semiconductor spintronic devices, motivated by potential spin-based information processing and storage applications. However, experimental progress towards manipulating the valley degree of freedom for potential valleytronic devices has been limited until very recently. We review the latest advances in valleytronics, which have largely been enabled by the isolation of 2D materials (such as graphene and semiconducting transition metal dichalcogenides) that host an easily accessible electronic valley degree of freedom, allowing for dynamic control.
Georgi, Howard; Kats, Yevgeny
2008-09-26
We discuss what can be learned about unparticle physics by studying simple quantum field theories in one space and one time dimension. We argue that the exactly soluble 2D theory of a massless fermion coupled to a massive vector boson, the Sommerfield model, is an interesting analog of a Banks-Zaks model, approaching a free theory at high energies and a scale-invariant theory with nontrivial anomalous dimensions at low energies. We construct a toy standard model coupling to the fermions in the Sommerfield model and study how the transition from unparticle behavior at low energies to free particle behavior at high energies manifests itself in interactions with the toy standard model particles.
Quantum coherence selective 2D Raman–2D electronic spectroscopy
Spencer, Austin P.; Hutson, William O.; Harel, Elad
2017-01-01
Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational–vibrational, electronic–vibrational and electronic–electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment–protein complexes. PMID:28281541
Quantum coherence selective 2D Raman-2D electronic spectroscopy
NASA Astrophysics Data System (ADS)
Spencer, Austin P.; Hutson, William O.; Harel, Elad
2017-03-01
Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational-vibrational, electronic-vibrational and electronic-electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment-protein complexes.
Quantum coherence selective 2D Raman-2D electronic spectroscopy.
Spencer, Austin P; Hutson, William O; Harel, Elad
2017-03-10
Electronic and vibrational correlations report on the dynamics and structure of molecular species, yet revealing these correlations experimentally has proved extremely challenging. Here, we demonstrate a method that probes correlations between states within the vibrational and electronic manifold with quantum coherence selectivity. Specifically, we measure a fully coherent four-dimensional spectrum which simultaneously encodes vibrational-vibrational, electronic-vibrational and electronic-electronic interactions. By combining near-impulsive resonant and non-resonant excitation, the desired fifth-order signal of a complex organic molecule in solution is measured free of unwanted lower-order contamination. A critical feature of this method is electronic and vibrational frequency resolution, enabling isolation and assignment of individual quantum coherence pathways. The vibronic structure of the system is then revealed within an otherwise broad and featureless 2D electronic spectrum. This method is suited for studying elusive quantum effects in which electronic transitions strongly couple to phonons and vibrations, such as energy transfer in photosynthetic pigment-protein complexes.
High-power 1.25 µm InAs QD VECSEL based on resonant periodic gain structure
NASA Astrophysics Data System (ADS)
Albrecht, Alexander R.; Rotter, Thomas J.; Hains, Christopher P.; Stintz, Andreas; Xin, Guofeng; Wang, Tsuei-Lian; Kaneda, Yushi; Moloney, Jerome V.; Malloy, Kevin J.; Balakrishnan, Ganesh
2011-03-01
We compare an InAs quantum dot (QD) vertical external-cavity surface-emitting laser (VECSEL) design consisting of 4 groups of 3 closely spaced QD layers with a resonant periodic gain (RPG) structure, where each of the 12 QD layers is placed at a separate field antinode. This increased the spacing between the QDs, reducing strain and greatly improving device performance. For thermal management, the GaAs substrate was thinned and indium bonded to CVD diamond. A fiber-coupled 808 nm diode laser was used as pump source, a 1% transmission output coupler completed the cavity. CW output powers over 4.5 W at 1250 nm were achieved.
Type Ia supernova diversity: Studies of SN 2007qd, SN 2008Q and SN 2011fe
NASA Astrophysics Data System (ADS)
McClelland, Colin M.
Type Ia supernovae (SN Ia) have proven to be incredibly useful as distance indicators and in nuclear astrophysics, but there remain many unanswered questions as to their nature. We examine three particular SN Ia at length in an attempt to provide constraints on both their theory and their application to cosmology. We first present SN 2007qd, one of the lowest-luminosity SN Ia ever discovered. It appears to belong to the SN 2002cx-like subclass of peculiar SN Ia. We observe and analyze the photospheric-phase spectra and photometry for this event and determine that, despite its extreme nature, it still appears to be a thermonuclear event rather than a core-collapse SN Ic. We also discover a possible relation between the luminosity and the low expansion velocities (2000˜7000 km/s) of similar events, and determine that they constitute a well-defined group of SN Ia. From the explosion kinematics and the content of the spectra, we argue that SN 2007qd was likely caused by a pure deflagration of a carbon and oxygen white dwarf. We then consider SN 2008Q, a SN Ia that exploded in the same early-type host galaxy as the peculiar SN 2000cx. This provided a chance for a direct comparison of two SN Ia at the same distance, extinction and host environment. We combine photometry from the ultraviolet through to the mid-infrared (MIR) and create a picture of how this SN evolved bolometrically over a span of two years. We discover that SN 2008Q was relatively bright in the ultraviolet, and characterize the possible existence of a class of SN Ia with similar UV excesses. We identify intrinsic differences between SN 2008Q and SN 2000cx, and discuss what this means for the variation in explosion and nebular physics in SN Ia events. We present next the mid-infrared and optical decay of SN 2011fe. This SN Ia exploded in the nearby galaxy M101, allowing observations of high signal-to-noise during the later phases. We examine this SN with Spitzer/IRAC MIR photometry and discover that the
Controlling avalanche criticality in 2D nano arrays
Zohar, Y. C.; Yochelis, S.; Dahmen, K. A.; Jung, G.; Paltiel, Y.
2013-01-01
Many physical systems respond to slowly changing external force through avalanches spanning broad range of sizes. Some systems crackle even without apparent external force, such as bursts of neuronal activity or charge transfer avalanches in 2D molecular layers. Advanced development of theoretical models describing disorder-induced critical phenomena calls for experiments probing the dynamics upon tuneable disorder. Here we show that isomeric structural transitions in 2D organic self-assembled monolayer (SAM) exhibit critical dynamics with experimentally tuneable disorder. The system consists of field effect transistor coupled through SAM to illuminated semiconducting nanocrystals (NCs). Charges photoinduced in NCs are transferred through SAM to the transistor surface and modulate its conductivity. Avalanches of isomeric structural transitions are revealed by measuring the current noise I(t) of the transistor. Accumulated surface traps charges reduce dipole moments of the molecules, decrease their coupling, and thus decrease the critical disorder of the SAM enabling its tuning during experiments. PMID:23677142
Controlling avalanche criticality in 2D nano arrays.
Zohar, Y C; Yochelis, S; Dahmen, K A; Jung, G; Paltiel, Y
2013-01-01
Many physical systems respond to slowly changing external force through avalanches spanning broad range of sizes. Some systems crackle even without apparent external force, such as bursts of neuronal activity or charge transfer avalanches in 2D molecular layers. Advanced development of theoretical models describing disorder-induced critical phenomena calls for experiments probing the dynamics upon tuneable disorder. Here we show that isomeric structural transitions in 2D organic self-assembled monolayer (SAM) exhibit critical dynamics with experimentally tuneable disorder. The system consists of field effect transistor coupled through SAM to illuminated semiconducting nanocrystals (NCs). Charges photoinduced in NCs are transferred through SAM to the transistor surface and modulate its conductivity. Avalanches of isomeric structural transitions are revealed by measuring the current noise I(t) of the transistor. Accumulated surface traps charges reduce dipole moments of the molecules, decrease their coupling, and thus decrease the critical disorder of the SAM enabling its tuning during experiments.
NASA Astrophysics Data System (ADS)
Chen, HuaJun; Zhu, KaDi
2015-05-01
Majorana fermions (MFs) are exotic particles that are their own anti-particles. Currently, the search for MFs occurring as quasiparticle excitations in condensed matter systems has attracted widespread interest, because of their importance in fundamental physics and potential applications in topological quantum computation based on solid-state devices. Motivated by recent experimental progress towards the detection and manipulation of MFs in hybrid semiconductor/superconductor heterostructures, in this review, we present a novel proposal to probe MFs in all-optical domain. We introduce a single quantum dot (QD), a hybrid quantum dot-nanomechanical resonators (QD-NR) system, and a carbon nanotube (CNT) resonator implanted in a single electron spin system with optical pump-probe technology to detect MFs, respectively. With this scheme, a possible Majorana signature is investigated via the probe absorption spectrum and nonlinear optical Kerr effect, and the coupling strength between MFs and the QD or the single electron spin is also determined. In the hybrid QD-NR system, vibration of the NR will enhance the nonlinear optical effect, which makes the MFs more sensitive for detection. In the CNT resonator with a single electron, the single electron spin can be considered as a sensitive probe, and the CNT resonator behaved as a phonon cavity is robust for detecting of MFs. This optical scheme will provide another method for the detection MFs and will open the door for new applications ranging from robust manipulation of MFs to quantum information processing based on MFs.
InAsP/AlGaInP/GaAs QD laser operating at ∼770 nm
NASA Astrophysics Data System (ADS)
Krysa, A. B.; Roberts, J. S.; Devenson, J.; Beanland, R.; Karomi, I.; Shutts, S.; Smowton, P. M.
2016-08-01
We present a study of metalorganic vapour phase epitaxy of ternary InAsP quantum dots in AlGaInP/GaAs for application in laser diodes. The properties of InAsP QD laser structures were compared with reference samples containing binary InP QDs. Based on X-ray diffraction, the molar fraction of arsenic in InAsP QDs was estimated to be ∼25%. Room temperature liquid contact electro-luminescence measurements revealed a long wavelength shift of the InAsP QD emission to ∼775 nm as compared with the InP QD emission at 716 nm and an increased full width at half maximum of the spontaneous emission (71 meV vs 50 meV). As cleaved, 4 mm long and 50 pm wide InAsP QD lasers operated in a pulsed regime at room temperature at ∼770 nm with a threshold current density of 155 A/cm2 and a maximum output optical power of at least 200 mW. The maximum operation temperature was at least 380 K.
Correlated electron transfer and nonlinear optical effects in QD sensitized solar cells
NASA Astrophysics Data System (ADS)
Dahnovsky, Yuri; Kolesov, Grigory
2013-04-01
Nonlinear optical properties in pump-probe experimental setups and photoelectric current are theoretically and computationally studied for both quantum dot sensitized solar cells (QDSSCs) and isolated quantum dots (QDs). A nonlinear polarization vector and correlated current are found from a solution of Kadanoff-Baym (KB) equations, which are solved by a novel efficient computational method based on a two-time spectral expansion (2TSE) of nonequilibrium Green's functions. In addition we study electron transfer within the uncorrelated Markovian approach. It is shown that differential transmission and electric current strongly depend on the value and the character of chemical bonding between a quantum dot and semiconductor surface. The higher the tunneling amplitude and bond width, the larger the differential transmission. The relaxation time for electronic states in a QD is also an important parameter indicating to the competition of two electron dynamics mechanisms, electron tunneling and electron relaxation. The higher the electron relaxation rate, the lower the discrepancy in the differential transmissions for QDSSCs and isolated QDs. The discrepancy between the markovian and KB approaches can reach as much as one order of magnitude.
High Operating Temperature Midwave Quantum Dot Barrier Infrared Detector (QD-BIRD)
NASA Technical Reports Server (NTRS)
Ting, David Z.; Soibel, Alexander; Hill, Cory J.; Keo, Sam A.; Mumolo, Jason M.; Gunapala, Sarath D.
2012-01-01
The nBn or XBn barrier infrared detector has the advantage of reduced dark current resulting from suppressed Shockley-Read-Hall (SRH) recombination and surface leakage. High performance detectors and focal plane arrays (FPAs) based on InAsSb absorber lattice matched to GaSb substrate, with a matching AlAsSb unipolar electron barrier, have been demonstrated. The band gap of lattice-matched InAsSb yields a detector cutoff wavelength of approximately 4.2 ??m when operating at 150K. We report results on extending the cutoff wavelength of midwave barrier infrared detectors by incorporating self-assembled InSb quantum dots into the active area of the detector. Using this approach, we were able to extend the detector cutoff wavelength to 6 ?m, allowing the coverage of the full midwave infrared (MWIR) transmission window. The quantum dot barrier infrared detector (QD-BIRD) shows infrared response at temperatures up to 225 K.
NKG2D ligands as therapeutic targets
Spear, Paul; Wu, Ming-Ru; Sentman, Marie-Louise; Sentman, Charles L.
2013-01-01
The Natural Killer Group 2D (NKG2D) receptor plays an important role in protecting the host from infections and cancer. By recognizing ligands induced on infected or tumor cells, NKG2D modulates lymphocyte activation and promotes immunity to eliminate ligand-expressing cells. Because these ligands are not widely expressed on healthy adult tissue, NKG2D ligands may present a useful target for immunotherapeutic approaches in cancer. Novel therapies targeting NKG2D ligands for the treatment of cancer have shown preclinical success and are poised to enter into clinical trials. In this review, the NKG2D receptor and its ligands are discussed in the context of cancer, infection, and autoimmunity. In addition, therapies targeting NKG2D ligands in cancer are also reviewed. PMID:23833565
Michael Ramsey-Musolf; Wick Haxton; Ching-Pang Liu
2002-03-29
Nuclear anapole moments are parity-odd, time-reversal-even E1 moments of the electromagnetic current operator. Although the existence of this moment was recognized theoretically soon after the discovery of parity nonconservation (PNC), its experimental isolation was achieved only recently, when a new level of precision was reached in a measurement of the hyperfine dependence of atomic PNC in 133Cs. An important anapole moment bound in 205Tl also exists. In this paper, we present the details of the first calculation of these anapole moments in the framework commonly used in other studies of hadronic PNC, a meson exchange potential that includes long-range pion exchange and enough degrees of freedom to describe the five independent S-P amplitudes induced by short-range interactions. The resulting contributions of pi-, rho-, and omega-exchange to the single-nucleon anapole moment, to parity admixtures in the nuclear ground state, and to PNC exchange currents are evaluated, using configuration-mixed shell-model wave functions. The experimental anapole moment constraints on the PNC meson-nucleon coupling constants are derived and compared with those from other tests of the hadronic weak interaction. While the bounds obtained from the anapole moment results are consistent with the broad ''reasonable ranges'' defined by theory, they are not in good agreement with the constraints from the other experiments. We explore possible explanations for the discrepancy and comment on the potential importance of new experiments.
Magnetic gating of a 2D topological insulator
NASA Astrophysics Data System (ADS)
Dang, Xiaoqian; Burton, J. D.; Tsymbal, Evgeny Y.
2016-09-01
Deterministic control of transport properties through manipulation of spin states is one of the paradigms of spintronics. Topological insulators offer a new playground for exploring interesting spin-dependent phenomena. Here, we consider a ferromagnetic ‘gate’ representing a magnetic adatom coupled to the topologically protected edge state of a two-dimensional (2D) topological insulator to modulate the electron transmission of the edge state. Due to the locked spin and wave vector of the transport electrons the transmission across the magnetic gate depends on the mutual orientation of the adatom magnetic moment and the current. If the Fermi energy matches an exchange-split bound state of the adatom, the electron transmission can be blocked due to the full back scattering of the incident wave. This antiresonance behavior is controlled by the adatom magnetic moment orientation so that the transmission of the edge state can be changed from 1 to 0. Expanding this consideration to a ferromagnetic gate representing a 1D chain of atoms shows a possibility to control the spin-dependent current of a strip of a 2D topological insulator by magnetization orientation of the ferromagnetic gate.
NASA Astrophysics Data System (ADS)
Grillot, F.; Naderi, N. A.; Pochet, M.; Lin, C.-Y.; Lester, L. F.
2009-02-01
The dramatic variation in the linewidth enhancement factor (αΗ-factor) that has been reported for quantum dot lasers makes them an interesting subject for optical feedback studies. A low αΗ-factor combined with a high damping factor is especially interesting because it should increase the tolerance to optical feedback in these devices and may offer potential advantages for direct modulation. In the particular case of QD lasers, the carrier density is not clearly clamped at threshold. The lasing wavelength can switch from the ground state (GS) to the excited state (ES) as the current injection increases meaning that a carrier accumulation occurs in the ES even though lasing in the GS is still occurring. The filling of the ES inevitably enhances the αΗ-factor of the GS above threshold as experimentally and numerically shown. Consequently, this strong variation of the GS αΗ-factor in comparison to QW devices, should theoretically produce a significant variation in the onset of coherence collapse due to feedback. This coherence collapse regime, in which the laser is subject to instabilities, is incompatible with data transmission because of the induced high bit-error rate. One method to investigate the tolerance to optical feedback is to compare experiment with the theoretical work introduced by Petermann. It will be presented that under specific conditions, i.e., in the case of a strong enhancement in the αΗ-factor, the feedback sensitivity of the laser can vary by as much as 10dB within the same device.
Moment inference from tomograms
Day-Lewis, F. D.; Chen, Y.; Singha, K.
2007-01-01
Time-lapse geophysical tomography can provide valuable qualitative insights into hydrologic transport phenomena associated with aquifer dynamics, tracer experiments, and engineered remediation. Increasingly, tomograms are used to infer the spatial and/or temporal moments of solute plumes; these moments provide quantitative information about transport processes (e.g., advection, dispersion, and rate-limited mass transfer) and controlling parameters (e.g., permeability, dispersivity, and rate coefficients). The reliability of moments calculated from tomograms is, however, poorly understood because classic approaches to image appraisal (e.g., the model resolution matrix) are not directly applicable to moment inference. Here, we present a semi-analytical approach to construct a moment resolution matrix based on (1) the classic model resolution matrix and (2) image reconstruction from orthogonal moments. Numerical results for radar and electrical-resistivity imaging of solute plumes demonstrate that moment values calculated from tomograms depend strongly on plume location within the tomogram, survey geometry, regularization criteria, and measurement error. Copyright 2007 by the American Geophysical Union.
Quantitative 2D liquid-state NMR.
Giraudeau, Patrick
2014-06-01
Two-dimensional (2D) liquid-state NMR has a very high potential to simultaneously determine the absolute concentration of small molecules in complex mixtures, thanks to its capacity to separate overlapping resonances. However, it suffers from two main drawbacks that probably explain its relatively late development. First, the 2D NMR signal is strongly molecule-dependent and site-dependent; second, the long duration of 2D NMR experiments prevents its general use for high-throughput quantitative applications and affects its quantitative performance. Fortunately, the last 10 years has witnessed an increasing number of contributions where quantitative approaches based on 2D NMR were developed and applied to solve real analytical issues. This review aims at presenting these recent efforts to reach a high trueness and precision in quantitative measurements by 2D NMR. After highlighting the interest of 2D NMR for quantitative analysis, the different strategies to determine the absolute concentrations from 2D NMR spectra are described and illustrated by recent applications. The last part of the manuscript concerns the recent development of fast quantitative 2D NMR approaches, aiming at reducing the experiment duration while preserving - or even increasing - the analytical performance. We hope that this comprehensive review will help readers to apprehend the current landscape of quantitative 2D NMR, as well as the perspectives that may arise from it.
NASA Technical Reports Server (NTRS)
Ting, David Z.-Y; Soibel, Alexander; Khoshakhlagh, Arezou; Keo, Sam A.; Nguyen, Jean; Hoglund, Linda; Mumolo, Jason M.; Liu, John K.; Rafol, Sir B.; Hill, Cory J.; Gunapala, Sarath D.
2012-01-01
The InAs/GaSb type-II superlattice based complementary barrier infrared detector (CBIRD) has already demonstrated very good performance in long-wavelength infrared (LWIR) detection. In this work, we describe results on a modified CBIRD device that incorporates a double tunnel junction contact designed for robust device and focal plane array processing. The new device also exhibited reduced turn-on voltage. We also report results on the quantum dot barrier infrared detector (QD-BIRD). By incorporating self-assembled InSb quantum dots into the InAsSb absorber of the standard nBn detector structure, the QD-BIRD extend the detector cutoff wavelength from approximately 4.2 micrometers to 6 micrometers, allowing the coverage of the mid-wavelength infrared (MWIR) transmission window. The device has been observed to show infrared response at 225 K.
Chang, D. . Dept. of Physics and Astronomy Fermi National Accelerator Lab., Batavia, IL ); Senjanovic, G. . Dept. of Theoretical Physics)
1990-01-01
We review attempts to achieve a large neutrino magnetic moment ({mu}{sub {nu}} {le} 10{sup {minus}11}{mu}{sub B}), while keeping neutrino light or massless. The application to the solar neutrino puzzle is discussed. 24 refs.
Annotated Bibliography of EDGE2D Use
J.D. Strachan and G. Corrigan
2005-06-24
This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables.
Staring 2-D hadamard transform spectral imager
Gentry, Stephen M.; Wehlburg, Christine M.; Wehlburg, Joseph C.; Smith, Mark W.; Smith, Jody L.
2006-02-07
A staring imaging system inputs a 2D spatial image containing multi-frequency spectral information. This image is encoded in one dimension of the image with a cyclic Hadamarid S-matrix. The resulting image is detecting with a spatial 2D detector; and a computer applies a Hadamard transform to recover the encoded image.
Bayesian 2D Current Reconstruction from Magnetic Images
NASA Astrophysics Data System (ADS)
Clement, Colin B.; Bierbaum, Matthew K.; Nowack, Katja; Sethna, James P.
We employ a Bayesian image reconstruction scheme to recover 2D currents from magnetic flux imaged with scanning SQUIDs (Superconducting Quantum Interferometric Devices). Magnetic flux imaging is a versatile tool to locally probe currents and magnetic moments, however present reconstruction methods sacrifice resolution due to numerical instability. Using state-of-the-art blind deconvolution techniques we recover the currents, point-spread function and height of the SQUID loop by optimizing the probability of measuring an image. We obtain uncertainties on these quantities by sampling reconstructions. This generative modeling technique could be used to develop calibration protocols for scanning SQUIDs, to diagnose systematic noise in the imaging process, and can be applied to many tools beyond scanning SQUIDs.
Ginsparg, P.
1991-01-01
These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.
Ginsparg, P.
1991-12-31
These are introductory lectures for a general audience that give an overview of the subject of matrix models and their application to random surfaces, 2d gravity, and string theory. They are intentionally 1.5 years out of date.
Brittle damage models in DYNA2D
Faux, D.R.
1997-09-01
DYNA2D is an explicit Lagrangian finite element code used to model dynamic events where stress wave interactions influence the overall response of the system. DYNA2D is often used to model penetration problems involving ductile-to-ductile impacts; however, with the advent of the use of ceramics in the armor-anti-armor community and the need to model damage to laser optics components, good brittle damage models are now needed in DYNA2D. This report will detail the implementation of four brittle damage models in DYNA2D, three scalar damage models and one tensor damage model. These new brittle damage models are then used to predict experimental results from three distinctly different glass damage problems.
NASA Astrophysics Data System (ADS)
Dekker, T.; de Zwart, S. T.; Willemsen, O. H.; Hiddink, M. G. H.; IJzerman, W. L.
2006-02-01
A prerequisite for a wide market acceptance of 3D displays is the ability to switch between 3D and full resolution 2D. In this paper we present a robust and cost effective concept for an auto-stereoscopic switchable 2D/3D display. The display is based on an LCD panel, equipped with switchable LC-filled lenticular lenses. We will discuss 3D image quality, with the focus on display uniformity. We show that slanting the lenticulars in combination with a good lens design can minimize non-uniformities in our 20" 2D/3D monitors. Furthermore, we introduce fractional viewing systems as a very robust concept to further improve uniformity in the case slanting the lenticulars and optimizing the lens design are not sufficient. We will discuss measurements and numerical simulations of the key optical characteristics of this display. Finally, we discuss 2D image quality, the switching characteristics and the residual lens effect.
2-d Finite Element Code Postprocessor
Sanford, L. A.; Hallquist, J. O.
1996-07-15
ORION is an interactive program that serves as a postprocessor for the analysis programs NIKE2D, DYNA2D, TOPAZ2D, and CHEMICAL TOPAZ2D. ORION reads binary plot files generated by the two-dimensional finite element codes currently used by the Methods Development Group at LLNL. Contour and color fringe plots of a large number of quantities may be displayed on meshes consisting of triangular and quadrilateral elements. ORION can compute strain measures, interface pressures along slide lines, reaction forces along constrained boundaries, and momentum. ORION has been applied to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.
Interpreting magnetic data by integral moments
NASA Astrophysics Data System (ADS)
Tontini, F. Caratori; Pedersen, L. B.
2008-09-01
The use of the integral moments for interpreting magnetic data is based on a very elegant property of potential fields, but in the past it has not been completely exploited due to problems concerning real data. We describe a new 3-D development of previous 2-D results aimed at determining the magnetization direction, extending the calculation to second-order moments to recover the centre of mass of the magnetization distribution. The method is enhanced to reduce the effects of the regional field that often alters the first-order solutions. Moreover, we introduce an iterative correction to properly assess the errors coming from finite-size surveys or interaction with neighbouring anomalies, which are the most important causes of the failing of the method for real data. We test the method on some synthetic examples, and finally, we show the results obtained by analysing the aeromagnetic anomaly of the Monte Vulture volcano in Southern Italy.
Chemical Approaches to 2D Materials.
Samorì, Paolo; Palermo, Vincenzo; Feng, Xinliang
2016-08-01
Chemistry plays an ever-increasing role in the production, functionalization, processing and applications of graphene and other 2D materials. This special issue highlights a selection of enlightening chemical approaches to 2D materials, which nicely reflect the breadth of the field and convey the excitement of the individuals involved in it, who are trying to translate graphene and related materials from the laboratory into a real, high-impact technology.
2D kinematic signatures of boxy/peanut bulges
NASA Astrophysics Data System (ADS)
Iannuzzi, Francesca; Athanassoula, E.
2015-07-01
We study the imprints of boxy/peanut structures on the 2D line-of-sight kinematics of simulated disc galaxies. The models under study belong to a family with varying initial gas fraction and halo triaxiality, plus few other control runs with different structural parameters; the kinematic information was extracted using the Voronoi-binning technique and parametrized up to the fourth order of a Gauss-Hermite series. Building on a previous work for the long-slit case, we investigate the 2D kinematic behaviour in the edge-on projection as a function of the boxy/peanut strength and position angle; we find that for the strongest structures the highest moments show characteristic features away from the mid-plane in a range of position angles. We also discuss the masking effect of a classical bulge and the ambiguity in discriminating kinematically this spherically symmetric component from a boxy/peanut bulge seen end-on. Regarding the face-on case, we extend existing results to encompass the effect of a second buckling and find that this phenomenon spurs an additional set of even deeper minima in the fourth moment. Finally, we show how the results evolve when inclining the disc away from perfectly edge-on and face-on. The behaviour of stars born during the course of the simulations is discussed and confronted to that of the pre-existing disc. The general aim of our study is providing a handle to identify boxy/peanut structures and their properties in latest generation Integral Field Unit observations of nearby disc galaxies.
ERIC Educational Resources Information Center
Goodrow, Mary Ellen
2000-01-01
Details how an unplanned activity involving spinning wool presented a teachable moment for children in a family child care setting. Notes how activities related to farming, spinning wool, and using wool cloth resulted from following the children's lead. Concludes that everyday activities provide opportunities to listen to children, learn about…
ERIC Educational Resources Information Center
Child & Youth Services, 2004
2004-01-01
This chapter presents additional stories and interpretations by John Korsmo, Molly Weingrod, Joseph Stanley, Quinn Wilder, Amy Evans, Rick Flowers, Arcelia Martinez, and Pam Ramsey. The stories and interpretations are presented as teachable moments that are examples of how people are learning to understand youthwork and, as such, are open to…
ERIC Educational Resources Information Center
Higgins, Chris
2014-01-01
In "The Humanist Moment," Chris Higgins sets out to recover a tenable, living humanism, rejecting both the version vilified by the anti-humanists and the one sentimentalized by the reactionary nostalgists. Rescuing humanism from such polemics is only the first step, as we find at least nine rival, contemporary definitions of humanism.…
ERIC Educational Resources Information Center
Espinoza, Roberta
2012-01-01
Educators can have a powerful influence on the future of low-income and minority students whose paths might appear uncertain. By developing trusting relationships, acting as mentors, and sharing information about the education system, teachers, counselors, and other adults can create pivotal moments that transform students' lives. Espinoza shares…
Bradburne, Christopher E; Delehanty, James B; Boeneman Gemmill, Kelly; Mei, Bing C; Mattoussi, Hedi; Susumu, Kimihiro; Blanco-Canosa, Juan B; Dawson, Philip E; Medintz, Igor L
2013-09-18
Interest in taking advantage of the unique spectral properties of semiconductor quantum dots (QDs) has driven their widespread use in biological applications such as in vitro cellular labeling/imaging and sensing. Despite their demonstrated utility, concerns over the potential toxic effects of QD core materials on cellular proliferation and homeostasis have persisted, leaving in question the suitability of QDs as alternatives for more traditional fluorescent materials (e.g., organic dyes, fluorescent proteins) for in vitro cellular applications. Surprisingly, direct comparative studies examining the cytotoxic potential of QDs versus these more traditional cellular labeling fluorophores remain limited. Here, using CdSe/ZnS (core/shell) QDs as a prototypical assay material, we present a comprehensive study in which we characterize the influence of QD dose (concentration and incubation time), QD surface capping ligand, and delivery modality (peptide or cationic amphiphile transfection reagent) on cellular viability in three human cell lines representing various morphological lineages (epithelial, endothelial, monocytic). We further compare the effects of QD cellular labeling on cellular proliferation relative to those associated with a panel of traditionally employed organic cell labeling fluorophores that span a broad spectral range. Our results demonstrate the important role played by QD dose, capping ligand structure, and delivery agent in modulating cellular toxicity. Further, the results show that at the concentrations and time regimes required for robust QD-based cellular labeling, the impact of our in-house synthesized QD materials on cellular proliferation is comparable to that of six commercial cell labeling fluorophores. Cumulatively, our results demonstrate that the proper tuning of QD dose, surface ligand, and delivery modality can provide robust in vitro cell labeling reagents that exhibit minimal impact on cellular viability.
Long-lived magnetoexcitons in 2D-fermion system
NASA Astrophysics Data System (ADS)
Kulik, L. V.; Zhuravlev, A. S.; Gorbunov, A. V.; Timofeev, V. B.; Kukushkin, I. V.
2017-01-01
The paper addresses the experimental technique that, when applied to a 2D-electron system in the integer quantum Hall regime with filling factor ν = 2 (the Hall insulating state), allows resonant excitation of magnetoexcitons, their detection, control of an ensemble of long-lived triplet excitons and investigation of their radiationless decay related to exciton spin relaxation into the ground state. The technique proposed enables independent control of photoexcited electrons and Fermi-holes using photoinduced resonance reflection spectra as well as estimate with a reasonable degree of accuracy the resulting density of photoinduced electron-hole pairs bound into magnetoexcitons. The mere existence of triplet excitons was directly established by inelastic light scattering spectra which were analyzed to determine the value of singlet-triplet exciton splitting. It was found that the lifetimes of triplet excitons conditioned by electron spin relaxation in highly perfect GaAs/AlGaAs heterostructures with highly mobile 2D electrons are extremely long exceeding 100 μs at T < 1 K. The paper presents a qualitative explanation of the long-spin relaxation lifetimes which are unprecedented for translation-invariant 2D systems. This enabled us to create sufficiently high concentrations of triplet magnetoexcitons, electrically neutral excitations following Bose-Einstein statistics, in a Fermi electron system and investigate their collective properties. At sufficiently high densities of triplet magnetoexcitons and low temperatures, T < 1 K, the degenerate magnetofermionic system exhibits condensation of the triplet magnetoexcitons into a qualitatively new collective state with unusual properties which occurs in the space of generalized moments (magnetic translation vectors). The occurrence of a condensed phase is accompanied with a significant decrease in the viscosity of the photoexcited system, which is responsible for electron spin transport at macroscopic distances, as well
Wang, Huan; Wang, Xiaomei; Wang, Jue; Fu, Weiling; Yao, Chunyan
2016-01-01
The detection of tumor markers is very important in early cancer diagnosis; however, tumor markers are usually present at very low concentrations, especially in the early stages of tumor development. Surface plasmon resonance (SPR) is widely used to detect biomolecular interactions; it has inherent advantages of being high-throughput, real-time, and label-free technique. However, its sensitivity needs essential improvement for practical applications. In this study, we developed a signal amplification strategy using antibody-quantum dot (QD) conjugates for the sensitive and quantitative detection of α-fetoprotein (AFP), carcinoembryonic antigen (CEA) and cytokeratin fragment 21-1 (CYFRA 21-1) in clinical samples. The use of a dual signal amplification strategy using AuNP-antibody and antibody-QD conjugates increased the signal amplification by 50-folds. The constructed SPR biosensor showed a detection limit as low as 0.1 ng/mL for AFP, CEA, and CYFRA 21-1. Moreover, the results obtained using this SPR biosensor were consistent with those obtained using the electrochemiluminescence method. Thus, the constructed SPR biosensor provides a highly sensitive and specific approach for the detection of tumor markers. This SPR biosensor can be expected to be readily applied for the detection of other tumor markers and can offer a potentially powerful solution for tumor screening. PMID:27615417
Orthotropic Piezoelectricity in 2D Nanocellulose
NASA Astrophysics Data System (ADS)
García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.
2016-10-01
The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V‑1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.
Orthotropic Piezoelectricity in 2D Nanocellulose
García, Y.; Ruiz-Blanco, Yasser B.; Marrero-Ponce, Yovani; Sotomayor-Torres, C. M.
2016-01-01
The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V−1, ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies. PMID:27708364
Orthotropic Piezoelectricity in 2D Nanocellulose.
García, Y; Ruiz-Blanco, Yasser B; Marrero-Ponce, Yovani; Sotomayor-Torres, C M
2016-10-06
The control of electromechanical responses within bonding regions is essential to face frontier challenges in nanotechnologies, such as molecular electronics and biotechnology. Here, we present Iβ-nanocellulose as a potentially new orthotropic 2D piezoelectric crystal. The predicted in-layer piezoelectricity is originated on a sui-generis hydrogen bonds pattern. Upon this fact and by using a combination of ab-initio and ad-hoc models, we introduce a description of electrical profiles along chemical bonds. Such developments lead to obtain a rationale for modelling the extended piezoelectric effect originated within bond scales. The order of magnitude estimated for the 2D Iβ-nanocellulose piezoelectric response, ~pm V(-1), ranks this material at the level of currently used piezoelectric energy generators and new artificial 2D designs. Such finding would be crucial for developing alternative materials to drive emerging nanotechnologies.
2D microwave imaging reflectometer electronics
Spear, A. G.; Domier, C. W. Hu, X.; Muscatello, C. M.; Ren, X.; Luhmann, N. C.; Tobias, B. J.
2014-11-15
A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.
Large Area Synthesis of 2D Materials
NASA Astrophysics Data System (ADS)
Vogel, Eric
Transition metal dichalcogenides (TMDs) have generated significant interest for numerous applications including sensors, flexible electronics, heterostructures and optoelectronics due to their interesting, thickness-dependent properties. Despite recent progress, the synthesis of high-quality and highly uniform TMDs on a large scale is still a challenge. In this talk, synthesis routes for WSe2 and MoS2 that achieve monolayer thickness uniformity across large area substrates with electrical properties equivalent to geological crystals will be described. Controlled doping of 2D semiconductors is also critically required. However, methods established for conventional semiconductors, such as ion implantation, are not easily applicable to 2D materials because of their atomically thin structure. Redox-active molecular dopants will be demonstrated which provide large changes in carrier density and workfunction through the choice of dopant, treatment time, and the solution concentration. Finally, several applications of these large-area, uniform 2D materials will be described including heterostructures, biosensors and strain sensors.
2D microwave imaging reflectometer electronics.
Spear, A G; Domier, C W; Hu, X; Muscatello, C M; Ren, X; Tobias, B J; Luhmann, N C
2014-11-01
A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.
Assessing 2D electrophoretic mobility spectroscopy (2D MOSY) for analytical applications.
Fang, Yuan; Yushmanov, Pavel V; Furó, István
2016-12-08
Electrophoretic displacement of charged entity phase modulates the spectrum acquired in electrophoretic NMR experiments, and this modulation can be presented via 2D FT as 2D mobility spectroscopy (MOSY) spectra. We compare in various mixed solutions the chemical selectivity provided by 2D MOSY spectra with that provided by 2D diffusion-ordered spectroscopy (DOSY) spectra and demonstrate, under the conditions explored, a superior performance of the former method. 2D MOSY compares also favourably with closely related LC-NMR methods. The shape of 2D MOSY spectra in complex mixtures is strongly modulated by the pH of the sample, a feature that has potential for areas such as in drug discovery and metabolomics. Copyright © 2016 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd. StartCopTextCopyright © 2016 The Authors. Magnetic Resonance in Chemistry published by John Wiley & Sons Ltd.
2D Distributed Sensing Via TDR
2007-11-02
plate VEGF CompositeSensor Experimental Setup Air 279 mm 61 78 VARTM profile: slope RTM profile: rectangle 22 1 Jul 2003© 2003 University of Delaware...2003 University of Delaware All rights reserved Vision: Non-contact 2D sensing ü VARTM setup constructed within TL can be sensed by its EM field: 2D...300.0 mm/ns. 1 2 1 Jul 2003© 2003 University of Delaware All rights reserved Model Validation “ RTM Flow” TDR Response to 139 mm VEGC
Inkjet printing of 2D layered materials.
Li, Jiantong; Lemme, Max C; Östling, Mikael
2014-11-10
Inkjet printing of 2D layered materials, such as graphene and MoS2, has attracted great interests for emerging electronics. However, incompatible rheology, low concentration, severe aggregation and toxicity of solvents constitute critical challenges which hamper the manufacturing efficiency and product quality. Here, we introduce a simple and general technology concept (distillation-assisted solvent exchange) to efficiently overcome these challenges. By implementing the concept, we have demonstrated excellent jetting performance, ideal printing patterns and a variety of promising applications for inkjet printing of 2D layered materials.
Parallel Stitching of 2D Materials.
Ling, Xi; Lin, Yuxuan; Ma, Qiong; Wang, Ziqiang; Song, Yi; Yu, Lili; Huang, Shengxi; Fang, Wenjing; Zhang, Xu; Hsu, Allen L; Bie, Yaqing; Lee, Yi-Hsien; Zhu, Yimei; Wu, Lijun; Li, Ju; Jarillo-Herrero, Pablo; Dresselhaus, Mildred; Palacios, Tomás; Kong, Jing
2016-03-23
Diverse parallel stitched 2D heterostructures, including metal-semiconductor, semiconductor-semiconductor, and insulator-semiconductor, are synthesized directly through selective "sowing" of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. The methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.
Beckett, Phil
2012-01-01
The technique of two-dimensional (2D) gel electrophoresis is a powerful tool for separating complex mixtures of proteins, but since its inception in the mid 1970s, it acquired the stigma of being a very difficult application to master and was generally used to its best effect by experts. The introduction of commercially available immobilized pH gradients in the early 1990s provided enhanced reproducibility and easier protocols, leading to a pronounced increase in popularity of the technique. However gel-to-gel variation was still difficult to control without the use of technical replicates. In the mid 1990s (at the same time as the birth of "proteomics"), the concept of multiplexing fluorescently labeled proteins for 2D gel separation was realized by Jon Minden's group and has led to the ability to design experiments to virtually eliminate gel-to-gel variation, resulting in biological replicates being used for statistical analysis with the ability to detect very small changes in relative protein abundance. This technology is referred to as 2D difference gel electrophoresis (2D DIGE).
Parallel stitching of 2D materials
Ling, Xi; Wu, Lijun; Lin, Yuxuan; ...
2016-01-27
Diverse parallel stitched 2D heterostructures, including metal–semiconductor, semiconductor–semiconductor, and insulator–semiconductor, are synthesized directly through selective “sowing” of aromatic molecules as the seeds in the chemical vapor deposition (CVD) method. Lastly, the methodology enables the large-scale fabrication of lateral heterostructures, which offers tremendous potential for its application in integrated circuits.
Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology
Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr
2016-01-01
The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct “beyond graphene” domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials. PMID:26861346
Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology.
Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr
2016-02-06
The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.
Wang, Ke; Li, Nan; Zhang, Jing; Zhang, Zhiqi; Dang, Fuquan
2017-01-15
In this work, we proposed a novel and facile method to monitor oxidase activities based on size-selective fluorescent quantum dot (QD)@metal-organic framework (MOF) core-shell nanocomposites (CSNCPs). The CSNCPs were synthesized from ZIF-8 and CdTe QDs in aqueous solution in 40min at room temperature with stirring. The prepared CdTe@ZIF-8 CSNCPs , which have excellent water dispersibility and stability, displays distinct fluorescence responses to hole scavengers of different molecular sizes (e.g., H2O2, substrate, and oxidase) due to the aperture limitation of the ZIF-8 shell. H2O2 can efficiently quench the fluorescence of CdTe@ZIF-8 CSNCPs over a linearity range of 1-100nM with a detection limit of 0.29nM, whereas large molecules such as substrate and oxidase have very little effect on its fluorescence. Therefore, the highly sensitive detection of oxidase activities was achieved by monitoring the fluorescence quenching of CdTe@ZIF-8 CSNCPs by H2O2 produced in the presence of substrate and oxidase, which is proportional to the oxidase activities. The linearity ranges of the uricase and glucose oxidase activity are 0.1-50U/L and 1-100U/L, respectively, and their detection limits are 0.024U/L and 0.26U/L, respectively. Therefore, the current QD@MOF CSNCPs based sensing system is a promising, widely applicable means of monitoring oxidase activities in biochemical research.
Compatible embedding for 2D shape animation.
Baxter, William V; Barla, Pascal; Anjyo, Ken-Ichi
2009-01-01
We present new algorithms for the compatible embedding of 2D shapes. Such embeddings offer a convenient way to interpolate shapes having complex, detailed features. Compared to existing techniques, our approach requires less user input, and is faster, more robust, and simpler to implement, making it ideal for interactive use in practical applications. Our new approach consists of three parts. First, our boundary matching algorithm locates salient features using the perceptually motivated principles of scale-space and uses these as automatic correspondences to guide an elastic curve matching algorithm. Second, we simplify boundaries while maintaining their parametric correspondence and the embedding of the original shapes. Finally, we extend the mapping to shapes' interiors via a new compatible triangulation algorithm. The combination of our algorithms allows us to demonstrate 2D shape interpolation with instant feedback. The proposed algorithms exhibit a combination of simplicity, speed, and accuracy that has not been achieved in previous work.
Schottky diodes from 2D germanane
NASA Astrophysics Data System (ADS)
Sahoo, Nanda Gopal; Esteves, Richard J.; Punetha, Vinay Deep; Pestov, Dmitry; Arachchige, Indika U.; McLeskey, James T.
2016-07-01
We report on the fabrication and characterization of a Schottky diode made using 2D germanane (hydrogenated germanene). When compared to germanium, the 2D structure has higher electron mobility, an optimal band-gap, and exceptional stability making germanane an outstanding candidate for a variety of opto-electronic devices. One-atom-thick sheets of hydrogenated puckered germanium atoms have been synthesized from a CaGe2 framework via intercalation and characterized by XRD, Raman, and FTIR techniques. The material was then used to fabricate Schottky diodes by suspending the germanane in benzonitrile and drop-casting it onto interdigitated metal electrodes. The devices demonstrate significant rectifying behavior and the outstanding potential of this material.
Extrinsic Cation Selectivity of 2D Membranes
2017-01-01
From a systematic study of the concentration driven diffusion of positive and negative ions across porous 2D membranes of graphene and hexagonal boron nitride (h-BN), we prove their cation selectivity. Using the current–voltage characteristics of graphene and h-BN monolayers separating reservoirs of different salt concentrations, we calculate the reversal potential as a measure of selectivity. We tune the Debye screening length by exchanging the salt concentrations and demonstrate that negative surface charge gives rise to cation selectivity. Surprisingly, h-BN and graphene membranes show similar characteristics, strongly suggesting a common origin of selectivity in aqueous solvents. For the first time, we demonstrate that the cation flux can be increased by using ozone to create additional pores in graphene while maintaining excellent selectivity. We discuss opportunities to exploit our scalable method to use 2D membranes for applications including osmotic power conversion. PMID:28157333
Static & Dynamic Response of 2D Solids
Lin, Jerry
1996-07-15
NIKE2D is an implicit finite-element code for analyzing the finite deformation, static and dynamic response of two-dimensional, axisymmetric, plane strain, and plane stress solids. The code is fully vectorized and available on several computing platforms. A number of material models are incorporated to simulate a wide range of material behavior including elasto-placicity, anisotropy, creep, thermal effects, and rate dependence. Slideline algorithms model gaps and sliding along material interfaces, including interface friction, penetration and single surface contact. Interactive-graphics and rezoning is included for analyses with large mesh distortions. In addition to quasi-Newton and arc-length procedures, adaptive algorithms can be defined to solve the implicit equations using the solution language ISLAND. Each of these capabilities and more make NIKE2D a robust analysis tool.
Explicit 2-D Hydrodynamic FEM Program
Lin, Jerry
1996-08-07
DYNA2D* is a vectorized, explicit, two-dimensional, axisymmetric and plane strain finite element program for analyzing the large deformation dynamic and hydrodynamic response of inelastic solids. DYNA2D* contains 13 material models and 9 equations of state (EOS) to cover a wide range of material behavior. The material models implemented in all machine versions are: elastic, orthotropic elastic, kinematic/isotropic elastic plasticity, thermoelastoplastic, soil and crushable foam, linear viscoelastic, rubber, high explosive burn, isotropic elastic-plastic, temperature-dependent elastic-plastic. The isotropic and temperature-dependent elastic-plastic models determine only the deviatoric stresses. Pressure is determined by one of 9 equations of state including linear polynomial, JWL high explosive, Sack Tuesday high explosive, Gruneisen, ratio of polynomials, linear polynomial with energy deposition, ignition and growth of reaction in HE, tabulated compaction, and tabulated.
Wittmann, Marc
2011-01-01
It has been suggested that perception and action can be understood as evolving in temporal epochs or sequential processing units. Successive events are fused into units forming a unitary experience or “psychological present.” Studies have identified several temporal integration levels on different time scales which are fundamental for our understanding of behavior and subjective experience. In recent literature concerning the philosophy and neuroscience of consciousness these separate temporal processing levels are not always precisely distinguished. Therefore, empirical evidence from psychophysics and neuropsychology on these distinct temporal processing levels is presented and discussed within philosophical conceptualizations of time experience. On an elementary level, one can identify a functional moment, a basic temporal building block of perception in the range of milliseconds that defines simultaneity and succession. Below a certain threshold temporal order is not perceived, individual events are processed as co-temporal. On a second level, an experienced moment, which is based on temporal integration of up to a few seconds, has been reported in many qualitatively different experiments in perception and action. It has been suggested that this segmental processing mechanism creates temporal windows that provide a logistical basis for conscious representation and the experience of nowness. On a third level of integration, continuity of experience is enabled by working memory in the range of multiple seconds allowing the maintenance of cognitive operations and emotional feelings, leading to mental presence, a temporal window of an individual’s experienced presence. PMID:22022310
Quasiparticle interference in unconventional 2D systems
NASA Astrophysics Data System (ADS)
Chen, Lan; Cheng, Peng; Wu, Kehui
2017-03-01
At present, research of 2D systems mainly focuses on two kinds of materials: graphene-like materials and transition-metal dichalcogenides (TMDs). Both of them host unconventional 2D electronic properties: pseudospin and the associated chirality of electrons in graphene-like materials, and spin-valley-coupled electronic structures in the TMDs. These exotic electronic properties have attracted tremendous interest for possible applications in nanodevices in the future. Investigation on the quasiparticle interference (QPI) in 2D systems is an effective way to uncover these properties. In this review, we will begin with a brief introduction to 2D systems, including their atomic structures and electronic bands. Then, we will discuss the formation of Friedel oscillation due to QPI in constant energy contours of electron bands, and show the basic concept of Fourier-transform scanning tunneling microscopy/spectroscopy (FT-STM/STS), which can resolve Friedel oscillation patterns in real space and consequently obtain the QPI patterns in reciprocal space. In the next two parts, we will summarize some pivotal results in the investigation of QPI in graphene and silicene, in which systems the low-energy quasiparticles are described by the massless Dirac equation. The FT-STM experiments show there are two different interference channels (intervalley and intravalley scattering) and backscattering suppression, which associate with the Dirac cones and the chirality of quasiparticles. The monolayer and bilayer graphene on different substrates (SiC and metal surfaces), and the monolayer and multilayer silicene on a Ag(1 1 1) surface will be addressed. The fifth part will introduce the FT-STM research on QPI in TMDs (monolayer and bilayer of WSe2), which allow us to infer the spin texture of both conduction and valence bands, and present spin-valley coupling by tracking allowed and forbidden scattering channels.
Compact 2-D graphical representation of DNA
NASA Astrophysics Data System (ADS)
Randić, Milan; Vračko, Marjan; Zupan, Jure; Novič, Marjana
2003-05-01
We present a novel 2-D graphical representation for DNA sequences which has an important advantage over the existing graphical representations of DNA in being very compact. It is based on: (1) use of binary labels for the four nucleic acid bases, and (2) use of the 'worm' curve as template on which binary codes are placed. The approach is illustrated on DNA sequences of the first exon of human β-globin and gorilla β-globin.
2D Metals by Repeated Size Reduction.
Liu, Hanwen; Tang, Hao; Fang, Minghao; Si, Wenjie; Zhang, Qinghua; Huang, Zhaohui; Gu, Lin; Pan, Wei; Yao, Jie; Nan, Cewen; Wu, Hui
2016-10-01
A general and convenient strategy for manufacturing freestanding metal nanolayers is developed on large scale. By the simple process of repeatedly folding and calendering stacked metal sheets followed by chemical etching, free-standing 2D metal (e.g., Ag, Au, Fe, Cu, and Ni) nanosheets are obtained with thicknesses as small as 1 nm and with sizes of the order of several micrometers.
Realistic and efficient 2D crack simulation
NASA Astrophysics Data System (ADS)
Yadegar, Jacob; Liu, Xiaoqing; Singh, Abhishek
2010-04-01
Although numerical algorithms for 2D crack simulation have been studied in Modeling and Simulation (M&S) and computer graphics for decades, realism and computational efficiency are still major challenges. In this paper, we introduce a high-fidelity, scalable, adaptive and efficient/runtime 2D crack/fracture simulation system by applying the mathematically elegant Peano-Cesaro triangular meshing/remeshing technique to model the generation of shards/fragments. The recursive fractal sweep associated with the Peano-Cesaro triangulation provides efficient local multi-resolution refinement to any level-of-detail. The generated binary decomposition tree also provides efficient neighbor retrieval mechanism used for mesh element splitting and merging with minimal memory requirements essential for realistic 2D fragment formation. Upon load impact/contact/penetration, a number of factors including impact angle, impact energy, and material properties are all taken into account to produce the criteria of crack initialization, propagation, and termination leading to realistic fractal-like rubble/fragments formation. The aforementioned parameters are used as variables of probabilistic models of cracks/shards formation, making the proposed solution highly adaptive by allowing machine learning mechanisms learn the optimal values for the variables/parameters based on prior benchmark data generated by off-line physics based simulation solutions that produce accurate fractures/shards though at highly non-real time paste. Crack/fracture simulation has been conducted on various load impacts with different initial locations at various impulse scales. The simulation results demonstrate that the proposed system has the capability to realistically and efficiently simulate 2D crack phenomena (such as window shattering and shards generation) with diverse potentials in military and civil M&S applications such as training and mission planning.
Engineering light outcoupling in 2D materials.
Lien, Der-Hsien; Kang, Jeong Seuk; Amani, Matin; Chen, Kevin; Tosun, Mahmut; Wang, Hsin-Ping; Roy, Tania; Eggleston, Michael S; Wu, Ming C; Dubey, Madan; Lee, Si-Chen; He, Jr-Hau; Javey, Ali
2015-02-11
When light is incident on 2D transition metal dichalcogenides (TMDCs), it engages in multiple reflections within underlying substrates, producing interferences that lead to enhancement or attenuation of the incoming and outgoing strength of light. Here, we report a simple method to engineer the light outcoupling in semiconducting TMDCs by modulating their dielectric surroundings. We show that by modulating the thicknesses of underlying substrates and capping layers, the interference caused by substrate can significantly enhance the light absorption and emission of WSe2, resulting in a ∼11 times increase in Raman signal and a ∼30 times increase in the photoluminescence (PL) intensity of WSe2. On the basis of the interference model, we also propose a strategy to control the photonic and optoelectronic properties of thin-layer WSe2. This work demonstrates the utilization of outcoupling engineering in 2D materials and offers a new route toward the realization of novel optoelectronic devices, such as 2D LEDs and solar cells.
Irreversibility-inversions in 2D turbulence
NASA Astrophysics Data System (ADS)
Bragg, Andrew; de Lillo, Filippo; Boffetta, Guido
2016-11-01
We consider a recent theoretical prediction that for inertial particles in 2D turbulence, the nature of the irreversibility of their pair dispersion inverts when the particle inertia exceeds a certain value. In particular, when the particle Stokes number, St , is below a certain value, the forward-in-time (FIT) dispersion should be faster than the backward-in-time (BIT) dispersion, but for St above this value, this should invert so that BIT becomes faster than FIT dispersion. This non-trivial behavior arises because of the competition between two physically distinct irreversibility mechanisms that operate in different regimes of St . In 3D turbulence, both mechanisms act to produce faster BIT than FIT dispersion, but in 2D, the two mechanisms have opposite effects because of the inverse energy cascade in the turbulent velocity field. We supplement the qualitative argument given by Bragg et al. by deriving quantitative predictions of this effect in the short-time dispersion limit. These predictions are then confirmed by results of inertial particle dispersion in a direct numerical simulation of 2D turbulence.
Probing the 2-D Kinematic Structure of Early-Type Galaxies Out to 3 Effective Radii
NASA Astrophysics Data System (ADS)
Proctor, Robert N.; Forbes, Duncan A.; Romanowsky, Aaron J.; Brodie, Jean P.; Strader, Jay; Spolaor, Max; Trevor Mendel, J.; Spitler, Lee
2010-06-01
We detail an innovative new technique for measuring the 2-D velocity moments (rotation velocity, velocity dispersion and Gauss-Hermite coefficients h3 and h4) using spectra from Keck DEIMOS multi-object spectroscopic observations. The data are used to reconstruct 2-D rotation velocity maps. Here we present data for one of five early-type galaxies whose kinematics we have measured out to ~3 effective radii (see [1]). From these data 2D kinematic maps are constructed. We show such analyses can provide significant insights into the global kinematic structure of galaxies, and, in some cases, challenge the accepted morphological classification. Our results are of particular importance to studies which attempt to classify galaxies by their kinematic structure within one effective radius, such as the recent definition of fast- and slow- rotator classes by the SAURON project.
Digital phase-stepping holographic interferometry in measuring 2-D density fields
NASA Astrophysics Data System (ADS)
Lanen, T. A. W. M.; Nebbeling, C.; van Ingen, J. L.
1990-06-01
This paper presents a holographic interferometer technique for measuring transparent (2-D or quasi 2-D) density fields. To be able to study the realization of such a field at a certain moment of time, the field is “frozen” on a holographic plate. During the reconstruction of the density field from the hologram the length of the path traversed by the reconstruction beam is diminished in equal steps by applying a computer controlled voltage to a piezo-electric crystal that translates a mirror. Four phase-stepped interferograms resulting from this pathlength variation are digitized and serve as input to an algorithm for computing the phase surface. The method is illustrated by measuring the basically 2-D density field existing around a heated horizontal cylinder in free convection.
2D superconductivity by ionic gating
NASA Astrophysics Data System (ADS)
Iwasa, Yoshi
2D superconductivity is attracting a renewed interest due to the discoveries of new highly crystalline 2D superconductors in the past decade. Superconductivity at the oxide interfaces triggered by LaAlO3/SrTiO3 has become one of the promising routes for creation of new 2D superconductors. Also, the MBE grown metallic monolayers including FeSe are also offering a new platform of 2D superconductors. In the last two years, there appear a variety of monolayer/bilayer superconductors fabricated by CVD or mechanical exfoliation. Among these, electric field induced superconductivity by electric double layer transistor (EDLT) is a unique platform of 2D superconductivity, because of its ability of high density charge accumulation, and also because of the versatility in terms of materials, stemming from oxides to organics and layered chalcogenides. In this presentation, the following issues of electric filed induced superconductivity will be addressed; (1) Tunable carrier density, (2) Weak pinning, (3) Absence of inversion symmetry. (1) Since the sheet carrier density is quasi-continuously tunable from 0 to the order of 1014 cm-2, one is able to establish an electronic phase diagram of superconductivity, which will be compared with that of bulk superconductors. (2) The thickness of superconductivity can be estimated as 2 - 10 nm, dependent on materials, and is much smaller than the in-plane coherence length. Such a thin but low resistance at normal state results in extremely weak pinning beyond the dirty Boson model in the amorphous metallic films. (3) Due to the electric filed, the inversion symmetry is inherently broken in EDLT. This feature appears in the enhancement of Pauli limit of the upper critical field for the in-plane magnetic fields. In transition metal dichalcogenide with a substantial spin-orbit interactions, we were able to confirm the stabilization of Cooper pair due to its spin-valley locking. This work has been supported by Grant-in-Aid for Specially
Increased efficiency in pn-junction PbS QD solar cells via NaHS treatment of the p-type layer
NASA Astrophysics Data System (ADS)
Speirs, Mark J.; Balazs, Daniel M.; Dirin, Dmitry N.; Kovalenko, Maksym V.; Loi, Maria Antonietta
2017-03-01
Lead sulfide quantum dot (PbS QD) solar cell efficiencies have improved rapidly over the past years due in large part to intelligent band alignment considerations. A pn-junction can be formed by connecting PbS layers with contrasting ligands. However, the resulting doping concentrations are typically low and cannot be effectively controlled. Here, we present a method of chemically p-doping films of thiol capped PbS QDs. P-n junction solar cells with increased doping in the p-type layer show improved short circuit current and fill factor, leading to an improvement in the power conversion efficiency from 7.1% to 7.6%. By examining Schottky diodes, field effect transistors, and the absorption spectra of treated and untreated PbS QDs, we show that the improved efficiency is due to the increased doping concentration in the thiol capped QD layer and to denser packing of the PbS QD film.
NASA Astrophysics Data System (ADS)
Cai, Chun-Yu; Zhao, Cui-Lan; Xiao, Jing-Lin
2015-02-01
We study the effects of external fields that are present in nanostructures and can trap particles and manipulate their quantum states. To obtain the effects of temperature on the strong coupling magnetopolaron's first-excited-state energy (FESE) and transition frequency (TF), we use the Lee-Low-Pines unitary transformation (LLPUT) and linear combination operation (LCO) methods. Numerical results, performed in the 2D RbCl parabolic quantum dot (QD), show that the magnetopolaron's FESE and TF (MFESETF) increase with increasing the effective confinement strength and cyclotron frequency (CF) of the magnetic field and temperature.
Periodically sheared 2D Yukawa systems
Kovács, Anikó Zsuzsa; Hartmann, Peter; Donkó, Zoltán
2015-10-15
We present non-equilibrium molecular dynamics simulation studies on the dynamic (complex) shear viscosity of a 2D Yukawa system. We have identified a non-monotonic frequency dependence of the viscosity at high frequencies and shear rates, an energy absorption maximum (local resonance) at the Einstein frequency of the system at medium shear rates, an enhanced collective wave activity, when the excitation is near the plateau frequency of the longitudinal wave dispersion, and the emergence of significant configurational anisotropy at small frequencies and high shear rates.
ENERGY LANDSCAPE OF 2D FLUID FORMS
Y. JIANG; ET AL
2000-04-01
The equilibrium states of 2D non-coarsening fluid foams, which consist of bubbles with fixed areas, correspond to local minima of the total perimeter. (1) The authors find an approximate value of the global minimum, and determine directly from an image how far a foam is from its ground state. (2) For (small) area disorder, small bubbles tend to sort inwards and large bubbles outwards. (3) Topological charges of the same sign repel while charges of opposite sign attract. (4) They discuss boundary conditions and the uniqueness of the pattern for fixed topology.
Codon Constraints on Closed 2D Shapes,
2014-09-26
19843$ CODON CONSTRAINTS ON CLOSED 2D SHAPES Go Whitman Richards "I Donald D. Hoffman’ D T 18 Abstract: Codons are simple primitives for describing plane...RSONAL AUT"ORtIS) Richards, Whitman & Hoffman, Donald D. 13&. TYPE OF REPORT 13b. TIME COVERED N/A P8 AT F RRrT t~r. Ago..D,) is, PlE COUNT Reprint...outlines, if figure and ground are ignored. Later, we will address the problem of indexing identical codon descriptors that have different figure
Remarks on thermalization in 2D CFT
NASA Astrophysics Data System (ADS)
de Boer, Jan; Engelhardt, Dalit
2016-12-01
We revisit certain aspects of thermalization in 2D conformal field theory (CFT). In particular, we consider similarities and differences between the time dependence of correlation functions in various states in rational and non-rational CFTs. We also consider the distinction between global and local thermalization and explain how states obtained by acting with a diffeomorphism on the ground state can appear locally thermal, and we review why the time-dependent expectation value of the energy-momentum tensor is generally a poor diagnostic of global thermalization. Since all 2D CFTs have an infinite set of commuting conserved charges, generic initial states might be expected to give rise to a generalized Gibbs ensemble rather than a pure thermal ensemble at late times. We construct the holographic dual of the generalized Gibbs ensemble and show that, to leading order, it is still described by a Banados-Teitelboim-Zanelli black hole. The extra conserved charges, while rendering c <1 theories essentially integrable, therefore seem to have little effect on large-c conformal field theories.
Microwave Assisted 2D Materials Exfoliation
NASA Astrophysics Data System (ADS)
Wang, Yanbin
Two-dimensional materials have emerged as extremely important materials with applications ranging from energy and environmental science to electronics and biology. Here we report our discovery of a universal, ultrafast, green, solvo-thermal technology for producing excellent-quality, few-layered nanosheets in liquid phase from well-known 2D materials such as such hexagonal boron nitride (h-BN), graphite, and MoS2. We start by mixing the uniform bulk-layered material with a common organic solvent that matches its surface energy to reduce the van der Waals attractive interactions between the layers; next, the solutions are heated in a commercial microwave oven to overcome the energy barrier between bulk and few-layers states. We discovered the minutes-long rapid exfoliation process is highly temperature dependent, which requires precise thermal management to obtain high-quality inks. We hypothesize a possible mechanism of this proposed solvo-thermal process; our theory confirms the basis of this novel technique for exfoliation of high-quality, layered 2D materials by using an as yet unknown role of the solvent.
Inquiry-Based Science: Turning Teachable Moments into Learnable Moments
ERIC Educational Resources Information Center
Haug, Berit S.
2014-01-01
This study examines how an inquiry-based approach to teaching and learning creates teachable moments that can foster conceptual understanding in students, and how teachers capitalize upon these moments. Six elementary school teachers were videotaped as they implemented an integrated inquiry-based science and literacy curriculum in their…
Wang Xiaoping; He Dongmei; Cai Jiye Chen Tongsheng; Zou Feiyan; Li Yalan; Wu Yangzhe; Chen, Zheng W.; Chen Yong
2009-02-06
A strategy involving the conjugation of fluorescent quantum dot (QD) with wheat germ agglutinin (WGA) acting as fluorescent and topographic probes prior to cell surface staining is developed for fluorescence microscopy and atomic force microscopy (AFM). This strategy provided at least two advantages: (a) an amplified fluorescence of WGA-QD aggregates, strongly resistant to photobleaching, ensures repeated/real-time observations of the probe-labeled cells by fluorescence microscopy; (b) the enlarged size of WGA-QD probe makes it possible for labeled WGA to be distinguished from other membrane proteins by AFM. Here, the random distribution of WGA-binding sites on non-crosslinked cells and the uneven or polarized reorganization due to WGA-induced crosslinking on cell surfaces were studied using AFM-detectable WGA-QD probe. Moreover, we developed a method to rapidly detect the WGA-induced rigidity alternation of the whole cells, which is efficient and has the potentiality of being developed to a useful tool in clinical diagnosis.
NASA Technical Reports Server (NTRS)
Hagiya, K.; Ohsumi, K.; Komatsu, M.; Mikouchi, T.; Zolensky, M. E.; Hirata, A.; Yamaguchi, S.; Kurokawa, A.
2016-01-01
The petrographic study of Itokawa particle, RA-QD02-0127 has been performed by SEM-EDS and optical microscope observations. The purpose of this study is to understand better the metamorphic and impact shock history of asteroid Itokawa, and other S-class asteroids.
NASA Astrophysics Data System (ADS)
Geru, I.; Bordian, O.; Culeac, I.; Turta, C.; Verlan, V.; Barba, A.
2015-02-01
We present experimental results on preparation and characterization of colloidal CdSe quantum dots (QD) in organic solvent. CdSe QDs were synthesized following a modified literature method and have been characterized by UV-Vis absorption and photoluminescent (PL) spectroscopy, as well as by 2D Diffusion Ordered Spectroscopy (DOSY) NMR. The average CdSe particles size estimated from the UV-Vis absorption spectra was found to be in the range 2.28 - 2.92 nm, which correlates very well with the results obtained from NMR measurements. The PL spectrum for CdSe nanodots can be characterized by a narrow emission band with the peak maximum shifting from 508 to 566 nm in dependence of the CdSe nanoparticle size. The PL is dominated by a near-band-edge emission, accompanied by a weak broad band in the near IR, related to the surface shallow trap emission.
Transition to turbulence: 2D directed percolation
NASA Astrophysics Data System (ADS)
Chantry, Matthew; Tuckerman, Laurette; Barkley, Dwight
2016-11-01
The transition to turbulence in simple shear flows has been studied for well over a century, yet in the last few years has seen major leaps forward. In pipe flow, this transition shows the hallmarks of (1 + 1) D directed percolation, a universality class of continuous phase transitions. In spanwisely confined Taylor-Couette flow the same class is found, suggesting the phenomenon is generic to shear flows. However in plane Couette flow the largest simulations and experiments to-date find evidence for a discrete transition. Here we study a planar shear flow, called Waleffe flow, devoid of walls yet showing the fundamentals of planar transition to turbulence. Working with a quasi-2D yet Navier-Stokes derived model of this flow we are able to attack the (2 + 1) D transition problem. Going beyond the system sizes previously possible we find all of the required scalings of directed percolation and thus establish planar shears flow in this class.
2D quantum gravity from quantum entanglement.
Gliozzi, F
2011-01-21
In quantum systems with many degrees of freedom the replica method is a useful tool to study the entanglement of arbitrary spatial regions. We apply it in a way that allows them to backreact. As a consequence, they become dynamical subsystems whose position, form, and extension are determined by their interaction with the whole system. We analyze, in particular, quantum spin chains described at criticality by a conformal field theory. Its coupling to the Gibbs' ensemble of all possible subsystems is relevant and drives the system into a new fixed point which is argued to be that of the 2D quantum gravity coupled to this system. Numerical experiments on the critical Ising model show that the new critical exponents agree with those predicted by the formula of Knizhnik, Polyakov, and Zamolodchikov.
Simulation of Yeast Cooperation in 2D.
Wang, M; Huang, Y; Wu, Z
2016-03-01
Evolution of cooperation has been an active research area in evolutionary biology in decades. An important type of cooperation is developed from group selection, when individuals form spatial groups to prevent them from foreign invasions. In this paper, we study the evolution of cooperation in a mixed population of cooperating and cheating yeast strains in 2D with the interactions among the yeast cells restricted to their small neighborhoods. We conduct a computer simulation based on a game theoretic model and show that cooperation is increased when the interactions are spatially restricted, whether the game is of a prisoner's dilemma, snow drifting, or mutual benefit type. We study the evolution of homogeneous groups of cooperators or cheaters and describe the conditions for them to sustain or expand in an opponent population. We show that under certain spatial restrictions, cooperator groups are able to sustain and expand as group sizes become large, while cheater groups fail to expand and keep them from collapse.
2D Electrostatic Actuation of Microshutter Arrays
NASA Technical Reports Server (NTRS)
Burns, Devin E.; Oh, Lance H.; Li, Mary J.; Jones, Justin S.; Kelly, Daniel P.; Zheng, Yun; Kutyrev, Alexander S.; Moseley, Samuel H.
2015-01-01
An electrostatically actuated microshutter array consisting of rotational microshutters (shutters that rotate about a torsion bar) were designed and fabricated through the use of models and experiments. Design iterations focused on minimizing the torsional stiffness of the microshutters, while maintaining their structural integrity. Mechanical and electromechanical test systems were constructed to measure the static and dynamic behavior of the microshutters. The torsional stiffness was reduced by a factor of four over initial designs without sacrificing durability. Analysis of the resonant behavior of the microshutter arrays demonstrates that the first resonant mode is a torsional mode occurring around 3000 Hz. At low vacuum pressures, this resonant mode can be used to significantly reduce the drive voltage necessary for actuation requiring as little as 25V. 2D electrostatic latching and addressing was demonstrated using both a resonant and pulsed addressing scheme.
Graphene suspensions for 2D printing
NASA Astrophysics Data System (ADS)
Soots, R. A.; Yakimchuk, E. A.; Nebogatikova, N. A.; Kotin, I. A.; Antonova, I. V.
2016-04-01
It is shown that, by processing a graphite suspension in ethanol or water by ultrasound and centrifuging, it is possible to obtain particles with thicknesses within 1-6 nm and, in the most interesting cases, 1-1.5 nm. Analogous treatment of a graphite suspension in organic solvent yields eventually thicker particles (up to 6-10 nm thick) even upon long-term treatment. Using the proposed ink based on graphene and aqueous ethanol with ethylcellulose and terpineol additives for 2D printing, thin (~5 nm thick) films with sheet resistance upon annealing ~30 MΩ/□ were obtained. With the ink based on aqueous graphene suspension, the sheet resistance was ~5-12 kΩ/□ for 6- to 15-nm-thick layers with a carrier mobility of ~30-50 cm2/(V s).
Canard configured aircraft with 2-D nozzle
NASA Technical Reports Server (NTRS)
Child, R. D.; Henderson, W. P.
1978-01-01
A closely-coupled canard fighter with vectorable two-dimensional nozzle was designed for enhanced transonic maneuvering. The HiMAT maneuver goal of a sustained 8g turn at a free-stream Mach number of 0.9 and 30,000 feet was the primary design consideration. The aerodynamic design process was initiated with a linear theory optimization minimizing the zero percent suction drag including jet effects and refined with three-dimensional nonlinear potential flow techniques. Allowances were made for mutual interference and viscous effects. The design process to arrive at the resultant configuration is described, and the design of a powered 2-D nozzle model to be tested in the LRC 16-foot Propulsion Wind Tunnel is shown.
Numerical Evaluation of 2D Ground States
NASA Astrophysics Data System (ADS)
Kolkovska, Natalia
2016-02-01
A ground state is defined as the positive radial solution of the multidimensional nonlinear problem
Metrology for graphene and 2D materials
NASA Astrophysics Data System (ADS)
Pollard, Andrew J.
2016-09-01
The application of graphene, a one atom-thick honeycomb lattice of carbon atoms with superlative properties, such as electrical conductivity, thermal conductivity and strength, has already shown that it can be used to benefit metrology itself as a new quantum standard for resistance. However, there are many application areas where graphene and other 2D materials, such as molybdenum disulphide (MoS2) and hexagonal boron nitride (h-BN), may be disruptive, areas such as flexible electronics, nanocomposites, sensing and energy storage. Applying metrology to the area of graphene is now critical to enable the new, emerging global graphene commercial world and bridge the gap between academia and industry. Measurement capabilities and expertise in a wide range of scientific areas are required to address this challenge. The combined and complementary approach of varied characterisation methods for structural, chemical, electrical and other properties, will allow the real-world issues of commercialising graphene and other 2D materials to be addressed. Here, examples of metrology challenges that have been overcome through a multi-technique or new approach are discussed. Firstly, the structural characterisation of defects in both graphene and MoS2 via Raman spectroscopy is described, and how nanoscale mapping of vacancy defects in graphene is also possible using tip-enhanced Raman spectroscopy (TERS). Furthermore, the chemical characterisation and removal of polymer residue on chemical vapour deposition (CVD) grown graphene via secondary ion mass spectrometry (SIMS) is detailed, as well as the chemical characterisation of iron films used to grow large domain single-layer h-BN through CVD growth, revealing how contamination of the substrate itself plays a role in the resulting h-BN layer. In addition, the role of international standardisation in this area is described, outlining the current work ongoing in both the International Organization of Standardization (ISO) and the
2-D Path Corrections for Local and Regional Coda Waves: A Test of Transportability
Mayeda, K M; Malagnini, L; Phillips, W S; Walter, W R; Dreger, D S; Morasca, P
2005-07-13
Reliable estimates of the seismic source spectrum are necessary for accurate magnitude, yield, and energy estimation. In particular, how seismic radiated energy scales with increasing earthquake size has been the focus of recent debate within the community and has direct implications on earthquake source physics studies as well as hazard mitigation. The 1-D coda methodology of Mayeda et al. [2003] has provided the lowest variance estimate of the source spectrum when compared against traditional approaches that use direct S-waves, thus making it ideal for networks that have sparse station distribution. The 1-D coda methodology has been mostly confined to regions of approximately uniform complexity. For larger, more geophysically complicated regions, 2-D path corrections may be required. We will compare performance of 1-D versus 2-D path corrections in a variety of regions. First, the complicated tectonics of the northern California region coupled with high quality broadband seismic data provides for an ideal ''apples-to-apples'' test of 1-D and 2-D path assumptions on direct waves and their coda. Next, we will compare results for the Italian Alps using high frequency data from the University of Genoa. For Northern California, we used the same station and event distribution and compared 1-D and 2-D path corrections and observed the following results: (1) 1-D coda results reduced the amplitude variance relative to direct S-waves by roughly a factor of 8 (800%); (2) Applying a 2-D correction to the coda resulted in up to 40% variance reduction from the 1-D coda results; (3) 2-D direct S-wave results, though better than 1-D direct waves, were significantly worse than the 1-D coda. We found that coda-based moment-rate source spectra derived from the 2-D approach were essentially identical to those from the 1-D approach for frequencies less than {approx}0.7-Hz, however for the high frequencies (0.7 {le} f {le} 8.0-Hz), the 2-D approach resulted in inter-station scatter
Theoretical study of the dipole moment function of OH(X 2Pi)
NASA Technical Reports Server (NTRS)
Langhoff, Stephen R.; Bauschlicher, Charles W., Jr.; Taylor, Peter R.
1987-01-01
A complete theoretical electric dipole moment function mu(r) is computed for OH(X 2Pi) at the full configuration-interaction (FCI) level for DZP + diffuse Gaussian basis set. The energy and dipole moment are also determined with 2d functions on oxygen at seven r values. The following methods are compared to the FCI for both the oxygen 1d and 2d basis sets: single-reference singles-plus-doubles configuration interaction (SDCI), SDCI with Davidson's correction, the coupled pair functional approach (CPF) and a modified form of CPF, CASSCF, and CASSCF-MRSDCI, and the external contracted CI(CCI) method. The dipole moments are evaluated both as an expectation value and by finite-field methods. The results support the superiority of evaluating the dipole moment as an energy derivative rather than as an expectation value.
Persistence Measures for 2d Soap Froth
NASA Astrophysics Data System (ADS)
Feng, Y.; Ruskin, H. J.; Zhu, B.
Soap froths as typical disordered cellular structures, exhibiting spatial and temporal evolution, have been studied through their distributions and topological properties. Recently, persistence measures, which permit representation of the froth as a two-phase system, have been introduced to study froth dynamics at different length scales. Several aspects of the dynamics may be considered and cluster persistence has been observed through froth experiment. Using a direct simulation method, we have investigated persistent properties in 2D froth both by monitoring the persistence of survivor cells, a topologically independent measure, and in terms of cluster persistence. It appears that the area fraction behavior for both survivor and cluster persistence is similar for Voronoi froth and uniform froth (with defects). Survivor and cluster persistent fractions are also similar for a uniform froth, particularly when geometries are constrained, but differences observed for the Voronoi case appear to be attributable to the strong topological dependency inherent in cluster persistence. Survivor persistence, on the other hand, depends on the number rather than size and position of remaining bubbles and does not exhibit the characteristic decay to zero.
SEM signal emulation for 2D patterns
NASA Astrophysics Data System (ADS)
Sukhov, Evgenii; Muelders, Thomas; Klostermann, Ulrich; Gao, Weimin; Braylovska, Mariya
2016-03-01
The application of accurate and predictive physical resist simulation is seen as one important use model for fast and efficient exploration of new patterning technology options, especially if fully qualified OPC models are not yet available at an early pre-production stage. The methodology of using a top-down CD-SEM metrology to extract the 3D resist profile information, such as the critical dimension (CD) at various resist heights, has to be associated with a series of presumptions which may introduce such small, but systematic CD errors. Ideally, the metrology effects should be carefully minimized during measurement process, or if possible be taken into account through proper metrology modeling. In this paper we discuss the application of a fast SEM signal emulation describing the SEM image formation. The algorithm is applied to simulated resist 3D profiles and produces emulated SEM image results for 1D and 2D patterns. It allows estimating resist simulation quality by comparing CDs which were extracted from the emulated and from the measured SEM images. Moreover, SEM emulation is applied for resist model calibration to capture subtle error signatures through dose and defocus. Finally, it should be noted that our SEM emulation methodology is based on the approximation of physical phenomena which are taking place in real SEM image formation. This approximation allows achieving better speed performance compared to a fully physical model.
Competing coexisting phases in 2D water
NASA Astrophysics Data System (ADS)
Zanotti, Jean-Marc; Judeinstein, Patrick; Dalla-Bernardina, Simona; Creff, Gaëlle; Brubach, Jean-Blaise; Roy, Pascale; Bonetti, Marco; Ollivier, Jacques; Sakellariou, Dimitrios; Bellissent-Funel, Marie-Claire
2016-05-01
The properties of bulk water come from a delicate balance of interactions on length scales encompassing several orders of magnitudes: i) the Hydrogen Bond (HBond) at the molecular scale and ii) the extension of this HBond network up to the macroscopic level. Here, we address the physics of water when the three dimensional extension of the HBond network is frustrated, so that the water molecules are forced to organize in only two dimensions. We account for the large scale fluctuating HBond network by an analytical mean-field percolation model. This approach provides a coherent interpretation of the different events experimentally (calorimetry, neutron, NMR, near and far infra-red spectroscopies) detected in interfacial water at 160, 220 and 250 K. Starting from an amorphous state of water at low temperature, these transitions are respectively interpreted as the onset of creation of transient low density patches of 4-HBonded molecules at 160 K, the percolation of these domains at 220 K and finally the total invasion of the surface by them at 250 K. The source of this surprising behaviour in 2D is the frustration of the natural bulk tetrahedral local geometry and the underlying very significant increase in entropy of the interfacial water molecules.
Competing coexisting phases in 2D water
Zanotti, Jean-Marc; Judeinstein, Patrick; Dalla-Bernardina, Simona; Creff, Gaëlle; Brubach, Jean-Blaise; Roy, Pascale; Bonetti, Marco; Ollivier, Jacques; Sakellariou, Dimitrios; Bellissent-Funel, Marie-Claire
2016-01-01
The properties of bulk water come from a delicate balance of interactions on length scales encompassing several orders of magnitudes: i) the Hydrogen Bond (HBond) at the molecular scale and ii) the extension of this HBond network up to the macroscopic level. Here, we address the physics of water when the three dimensional extension of the HBond network is frustrated, so that the water molecules are forced to organize in only two dimensions. We account for the large scale fluctuating HBond network by an analytical mean-field percolation model. This approach provides a coherent interpretation of the different events experimentally (calorimetry, neutron, NMR, near and far infra-red spectroscopies) detected in interfacial water at 160, 220 and 250 K. Starting from an amorphous state of water at low temperature, these transitions are respectively interpreted as the onset of creation of transient low density patches of 4-HBonded molecules at 160 K, the percolation of these domains at 220 K and finally the total invasion of the surface by them at 250 K. The source of this surprising behaviour in 2D is the frustration of the natural bulk tetrahedral local geometry and the underlying very significant increase in entropy of the interfacial water molecules. PMID:27185018
Point estimates for probability moments
Rosenblueth, Emilio
1975-01-01
Given a well-behaved real function Y of a real random variable X and the first two or three moments of X, expressions are derived for the moments of Y as linear combinations of powers of the point estimates y(x+) and y(x-), where x+ and x- are specific values of X. Higher-order approximations and approximations for discontinuous Y using more point estimates are also given. Second-moment approximations are generalized to the case when Y is a function of several variables. PMID:16578731
Spectral moments of fullerene cages
NASA Astrophysics Data System (ADS)
Zhang, Hongxing; Balasubramanian, K.
Based on the symmetric method, analytical expression or recursive relations for the spectral moments of the C20, C24, C26, C28, C30, C32, C36, C38, C40, C42, C44, C50 and C60 fullerene cage clusters are obtained by factoring the original graphs and the corresponding characteristic polynomials into their smaller subgraphs and subpolynomials. We also give numerical results for the spectral moments. It is demonstrated that the symmetric method is feasible in enumerating the moments as well as factoring the characteristic polynomials for fullerene cages.
NASA Astrophysics Data System (ADS)
Cheng, Chingyun; Kangara, Jayampathi; Arakelyan, Ilya; Thomas, John
2016-05-01
We tune the dimensionality of a strongly interacting degenerate 6 Li Fermi gas from 2D to quasi-2D, by adjusting the radial confinement of pancake-shaped clouds to control the radial chemical potential. In the 2D regime with weak radial confinement, the measured pair binding energies are in agreement with 2D-BCS mean field theory, which predicts dimer pairing energies in the many-body regime. In the qausi-2D regime obtained with increased radial confinement, the measured pairing energy deviates significantly from 2D-BCS theory. In contrast to the pairing energy, the measured radii of the cloud profiles are not fit by 2D-BCS theory in either the 2D or quasi-2D regimes, but are fit in both regimes by a beyond mean field polaron-model of the free energy. Supported by DOE, ARO, NSF, and AFOSR.
Lagrangian statistics in laboratory 2D turbulence
NASA Astrophysics Data System (ADS)
Xia, Hua; Francois, Nicolas; Punzmann, Horst; Shats, Michael
2014-05-01
Turbulent mixing in liquids and gases is ubiquitous in nature and industrial flows. Understanding statistical properties of Lagrangian trajectories in turbulence is crucial for a range of problems such as spreading of plankton in the ocean, transport of pollutants, etc. Oceanic data on trajectories of the free-drifting instruments, indicate that the trajectory statistics can often be described by a Lagrangian integral scale. Turbulence however is a state of a flow dominated by a hierarchy of scales, and it is not clear which of these scales mostly affect particle dispersion. Moreover, coherent structures often coexist with turbulence in laboratory experiments [1]. The effect of coherent structures on particle dispersion in turbulent flows is not well understood. Recent progress in scientific imaging and computational power made it possible to tackle this problem experimentally. In this talk, we report the analysis of the higher order Lagrangian statistics in laboratory two-dimensional turbulence. Our results show that fluid particle dispersion is diffusive and it is determined by a single measurable Lagrangian scale related to the forcing scale [2]. Higher order moments of the particle dispersion show strong self-similarity in fully developed turbulence [3]. Here we introduce a new dispersion law that describes single particle dispersion during the turbulence development [4]. These results offer a new way of predicting dispersion in turbulent flows in which one of the low energy scales are persistent. It may help better understanding of drifter Lagrangian statistics in the regions of the ocean where small scale coherent eddies are present [5]. Reference: 1. H. Xia, H. Punzmann, G. Falkovich and M. Shats, Physical Review Letters, 101, 194504 (2008) 2. H. Xia, N. Francois, H. Punzmann, and M. Shats, Nature Communications, 4, 2013 (2013) 3. R. Ferrari, A.J. Manfroi , W.R. Young, Physica D 154 111 (2001) 4. H. Xia, N. Francois, H. Punzmann and M. Shats, submitted (2014
2D discrete Fourier transform on sliding windows.
Park, Chun-Su
2015-03-01
Discrete Fourier transform (DFT) is the most widely used method for determining the frequency spectra of digital signals. In this paper, a 2D sliding DFT (2D SDFT) algorithm is proposed for fast implementation of the DFT on 2D sliding windows. The proposed 2D SDFT algorithm directly computes the DFT bins of the current window using the precalculated bins of the previous window. Since the proposed algorithm is designed to accelerate the sliding transform process of a 2D input signal, it can be directly applied to computer vision and image processing applications. The theoretical analysis shows that the computational requirement of the proposed 2D SDFT algorithm is the lowest among existing 2D DFT algorithms. Moreover, the output of the 2D SDFT is mathematically equivalent to that of the traditional DFT at all pixel positions.
NASA Astrophysics Data System (ADS)
Ostrovsky, Dmitry
2016-09-01
A new family of Barnes beta distributions on (0, ∞) is introduced and its infinite divisibility, moment determinacy, scaling, and factorization properties are established. The Morris integral probability distribution is constructed from Barnes beta distributions of types (1, 0) and (2, 2), and its moment determinacy and involution invariance properties are established. For application, the maximum distributions of the 2D gaussian free field on the unit interval and circle with a non-random logarithmic potential are conjecturally related to the critical Selberg and Morris integral probability distributions, respectively, and expressed in terms of sums of Barnes beta distributions of types (1, 0) and (2, 2).
MAGNUM2D. Radionuclide Transport Porous Media
Langford, D.W.; Baca, R.G.
1989-03-01
MAGNUM2D was developed to analyze thermally driven fluid motion in the deep basalts below the Paco Basin at the Westinghouse Hanford Site. Has been used in the Basalt Waste Isolation Project to simulate nonisothermal groundwater flow in a heterogeneous anisotropic medium and heat transport in a water/rock system near a high level nuclear waste repository. Allows three representations of the hydrogeologic system: an equivalent porous continuum, a system of discrete, unfilled, and interconnecting fractures separated by impervious rock mass, and a low permeability porous continuum with several discrete, unfilled fractures traversing the medium. The calculations assume local thermodynamic equilibrium between the rock and groundwater, nonisothermal Darcian flow in the continuum portions of the rock, and nonisothermal Poiseuille flow in discrete unfilled fractures. In addition, the code accounts for thermal loading within the elements, zero normal gradient and fixed boundary conditions for both temperature and hydraulic head, and simulation of the temperature and flow independently. The Q2DGEOM preprocessor was developed to generate, modify, plot and verify quadratic two dimensional finite element geometries. The BCGEN preprocessor generates the boundary conditions for head and temperature and ICGEN generates the initial conditions. The GRIDDER postprocessor interpolates nonregularly spaced nodal flow and temperature data onto a regular rectangular grid. CONTOUR plots and labels contour lines for a function of two variables and PARAM plots cross sections and time histories for a function of time and one or two spatial variables. NPRINT generates data tables that display the data along horizontal or vertical cross sections. VELPLT differentiates the hydraulic head and buoyancy data and plots the velocity vectors. The PATH postprocessor plots flow paths and computes the corresponding travel times.
MAGNUM2D. Radionuclide Transport Porous Media
Langford, D.W.; Baca, R.G.
1988-08-01
MAGNUM2D was developed to analyze thermally driven fluid motion in the deep basalts below the Paco Basin at the Westinghouse Hanford Site. Has been used in the Basalt Waste Isolation Project to simulate nonisothermal groundwater flow in a heterogeneous anisotropic medium and heat transport in a water/rock system near a high level nuclear waste repository. Allows three representations of the hydrogeologic system: an equivalent porous continuum, a system of discrete, unfilled, and interconnecting fractures separated by impervious rock mass, and a low permeability porous continuum with several discrete, unfilled fractures traversing the medium. The calculation assumes local thermodynamic equilibrium between the rock and groundwater, nonisothermal Darcian flow in the continuum portions of the rock, and nonisothermal Poiseuille flow in discrete unfilled fractures. In addition, the code accounts for thermal loading within the elements, zero normal gradient and fixed boundary conditions for both temperature and hydraulic head, and simulation of the temperature and flow independently. The Q2DGEOM preprocessor was developed to generate, modify, plot and verify quadratic two dimensional finite element geometries. The BCGEN preprocessor generates the boundary conditions for head and temperature and ICGEN generates the initial conditions. The GRIDDER postprocessor interpolates nonregularly spaced nodal flow and temperature data onto a regular rectangular grid. CONTOUR plots and labels contour lines for a function of two variables and PARAM plots cross sections and time histories for a function of time and one or two spatial variables. NPRINT generates data tables that display the data along horizontal or vertical cross sections. VELPLT differentiates the hydraulic head and buoyancy data and plots the velocity vectors. The PATH postprocessor plots flow paths and computes the corresponding travel times.
Generates 2D Input for DYNA NIKE & TOPAZ
Hallquist, J. O.; Sanford, Larry
1996-07-15
MAZE is an interactive program that serves as an input and two-dimensional mesh generator for DYNA2D, NIKE2D, TOPAZ2D, and CHEMICAL TOPAZ2D. MAZE also generates a basic template for ISLAND input. MAZE has been applied to the generation of input data to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.
MAZE96. Generates 2D Input for DYNA NIKE & TOPAZ
Sanford, L.; Hallquist, J.O.
1992-02-24
MAZE is an interactive program that serves as an input and two-dimensional mesh generator for DYNA2D, NIKE2D, TOPAZ2D, and CHEMICAL TOPAZ2D. MAZE also generates a basic template for ISLAND input. MAZE has been applied to the generation of input data to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.
NIKE2D96. Static & Dynamic Response of 2D Solids
Raboin, P.; Engelmann, B.; Halquist, J.O.
1992-01-24
NIKE2D is an implicit finite-element code for analyzing the finite deformation, static and dynamic response of two-dimensional, axisymmetric, plane strain, and plane stress solids. The code is fully vectorized and available on several computing platforms. A number of material models are incorporated to simulate a wide range of material behavior including elasto-placicity, anisotropy, creep, thermal effects, and rate dependence. Slideline algorithms model gaps and sliding along material interfaces, including interface friction, penetration and single surface contact. Interactive-graphics and rezoning is included for analyses with large mesh distortions. In addition to quasi-Newton and arc-length procedures, adaptive algorithms can be defined to solve the implicit equations using the solution language ISLAND. Each of these capabilities and more make NIKE2D a robust analysis tool.
Osiry, H.; Cano, A.; Lemus-Santana, A.A.; Rodríguez, A.; Carbonio, R.E.; Reguera, E.
2015-10-15
This contribution discusses the intercalation of imidazole and its 2-ethyl derivative, and pyridine in 2D copper nitroprusside. In the interlayer region, neighboring molecules remain interacting throu gh their dipole and quadrupole moments, which supports the solid 3D crystal structure. The crystal structure of this series of intercalation compounds was solved and refined from powder X-ray diffraction patterns complemented with spectroscopic information. The intermolecular interactions were studied from the refined crystal structures and low temperature magnetic measurements. Due to strong attractive forces between neighboring molecules, the resulting π–π cloud overlapping enables the ferromagnetic coupling between metal centers on neighboring layers, which was actually observed for the solids containing imidazole and pyridine as intercalated molecules. For these two solids, the magnetic data were properly described with a model of six neighbors. For the solid containing 2-ethylimidazole and for 2D copper nitroprusside, a model of four neighbors in a plane is sufficient to obtain a reliable data fitting. - Highlights: • Intercalation of organic molecules in 2D copper (II) nitroprusside. • Molecular properties of intercalation compounds of 2D copper (II) nitroprusside. • Magnetic properties of hybrid inorganic–organic solids. • Hybrid inorganic–organic 3D framework.
Second Moments (planar Moments) and Their Application in Spectroscopy
NASA Astrophysics Data System (ADS)
Bohn, Robert K.; Montgomery, John A., Jr.; Michels, H. Harvey; Byrd, Jason N.
2013-06-01
Second moments, also called planar moments (P_{ii} = Σ m_{i}^{} x_{i}^{2}), are the spectroscopic parameters used to determine substitution structures (r_{s}) ) by Kraitchman''s method from spectra of a molecule and its isotopologs. They are also useful for discussing other molecular structural properties. Just as bond lengths and angles are considered transferable among similar molecules, second moments of many common groups are also transferable. This paper discusses applications of second moments of methylene/methyl groups, singly or multiply, isopropyl/tert-butyl groups, phenyl groups, per{f}{l}uoro methylene/methyl groups, combinations of any of them, and planarity of molecules, the historically most common application of second moments. The inertial defect is Δ = (I_{c} - I_{a} - I_{b}) or -2P_{cc}. Some authors err by assuming each isotopolog provides three independent rotational constants, but in some cases they are not all independent. J. Kraitchman, Am. J. Phys. {21 (17), 1953.}
Inquiry-Based Science: Turning Teachable Moments into Learnable Moments
NASA Astrophysics Data System (ADS)
Haug, Berit S.
2014-02-01
This study examines how an inquiry-based approach to teaching and learning creates teachable moments that can foster conceptual understanding in students, and how teachers capitalize upon these moments. Six elementary school teachers were videotaped as they implemented an integrated inquiry-based science and literacy curriculum in their classrooms. In this curriculum, science inquiry implies that students search for evidence in order to make and revise explanations based on the evidence found and through critical and logical thinking. Furthermore, the curriculum material is designed to address science key concepts multiple times through multiple modalities (do it, say it, read it, write it). Two types of teachable moments were identified: planned and spontaneous. Results suggest that the consolidation phases of inquiry, when students reinforce new knowledge and connect their empirical findings to theory, can be considered as planned teachable moments. These are phases of inquiry during which the teacher should expect, and be prepared for, student utterances that create opportunities to further student learning. Spontaneous teachable moments are instances when the teacher must choose to either follow the pace of the curriculum or adapt to the students' need. One implication of the study is that more teacher support is required in terms of how to plan for and effectively utilize the consolidation phases of inquiry.
Gao, Yangyang; Dong, Qigeqi; Lan, Shi; Cai, Qian; Simalou, Oudjaniyobi; Zhang, Shiqi; Gao, Ge; Chokto, Harnoode; Dong, Alideertu
2015-05-13
Quantum dots (QDs) as potent candidates possess advantageous superiority in fluorescence imaging applications, but they are susceptible to the biological circumstances (e.g., bacterial environment), leading to fluorescence quenching or lose of fluorescent properties. In this work, CdTe QDs were embedded into mesoporous silica nanospheres (m-SiO2 NSs) for preventing QD agglomeration, and then CdTe QD-embedded m-SiO2 NSs (m-SiO2/CdTe NSs) were modified with Ag nanoparticles (Ag NPs) to prevent bacteria invasion for enhanced anticounterfeit applications. The m-SiO2 NSs, which serve as intermediate layers to combine CdTe QDs with Ag NPs, help us establish a highly fluorescent and long-term antibacterial system (i.e., m-SiO2/CdTe/Ag NSs). More importantly, CdTe QD-embedded m-SiO2 NSs showed fluorescence quenching when they encounter bacteria, which was avoided by attaching Ag NPs outside. Ag NPs are superior to CdTe QDs for preventing bacteria invasion because of the structure (well-dispersed Ag NPs), size (small diameter), and surface charge (positive zeta potentials) of Ag NPs. The plausible antibacterial mechanisms of m-SiO2/CdTe/Ag NSs toward both Gram-positive and Gram-negative bacteria were established. As for potential applications, m-SiO2/CdTe/Ag NSs were developed as fluorescent anticounterfeiting ink for enhanced imaging applications.
Kim, Seul-Ki; Kwen, Hai-Doo; Choi, Seong-Ho
2011-01-01
An Acaligense sp.-immobilized biosensor was fabricated based on QD-MWNT composites as an electron transfer mediator and a microbe immobilization support by a one-step radiation reaction and used for sensing phenolic compounds in commercial red wines. First, a quantum dot-modified multi-wall carbon nanotube (QD-MWNT) composite was prepared in the presence of MWNT by a one-step radiation reaction in an aqueous solution at room temperature. The successful preparation of the QD-MWNT composite was confirmed by XPS, TEM, and elemental analysis. Second, the microbial biosensor was fabricated by immobilization of Acaligense sp. on the surface of the composite thin film of a glassy carbon (GC) electrode, which was prepared by a hand casting method with a mixture of the previously obtained composite and Nafion solution. The sensing ranges of the microbial biosensor based on CdS-MWNT and Cu(2)S-MWNT supports were 0.5-5.0 mM and 0.7-10 mM for phenol in a phosphate buffer solution, respectively. Total concentration of phenolic compounds contained in commercial red wines was also determined using the prepared microbial immobilized biosensor.
Zeng, Chao; Wei, Jie; Li, Hui; Yang, Tuo; Gao, Shu-guang; Li, Yu-sheng; Xiong, Yi-lin; Xiao, Wen-feng; Luo, Wei; Yang, Tu-bao; Lei, Guang-hua
2015-01-01
This network meta-analysis aimed to investigate the effectiveness and safety of 100 mg BID and 200 mg QD oral celecoxib in the treatment of OA of the knee or hip. PubMed, Embase and Cochrane Library were searched through from inception to August 2014. Bayesian network meta-analysis was used to combine direct and indirect evidences on treatment effectiveness and safety. A total of 24 RCTs covering 11696 patients were included. For the comparison in between the two dosage regimens, 100 mg BID oral celecoxib exhibited a greater probability to be the preferred one either in terms of pain intensity or function at the last follow-up time point. For total gastrointestinal (GI) adverse effects (AEs), both of the two dosage regimens demonstrated a higher incidence compared to the placebo group. Further analyses of GI AEs revealed that only 200 mg QD was associated with a significantly higher risk of abdominal pain when compared with placebo. Furthermore, 100 mg BID showed a significantly lower incidence of skin AEs when compared with 200 mg QD and placebo. Maybe 100 mg BID should be considered as the preferred dosage regimen in the treatment of knee or hip OA. PMID:26012738
CYP2D7 Sequence Variation Interferes with TaqMan CYP2D6*15 and *35 Genotyping
Riffel, Amanda K.; Dehghani, Mehdi; Hartshorne, Toinette; Floyd, Kristen C.; Leeder, J. Steven; Rosenblatt, Kevin P.; Gaedigk, Andrea
2016-01-01
TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs) some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false-positive CYP2D6*15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6*15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL)-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6*35) which is also located in exon 1. Although alternative CYP2D6*15 and *35 assays resolved the issue, we discovered a novel CYP2D6*15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6*15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696) SNP of CYP2D6*43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer and/or probe regions can impact
CYP2D7 Sequence Variation Interferes with TaqMan CYP2D6 (*) 15 and (*) 35 Genotyping.
Riffel, Amanda K; Dehghani, Mehdi; Hartshorne, Toinette; Floyd, Kristen C; Leeder, J Steven; Rosenblatt, Kevin P; Gaedigk, Andrea
2015-01-01
TaqMan™ genotyping assays are widely used to genotype CYP2D6, which encodes a major drug metabolizing enzyme. Assay design for CYP2D6 can be challenging owing to the presence of two pseudogenes, CYP2D7 and CYP2D8, structural and copy number variation and numerous single nucleotide polymorphisms (SNPs) some of which reflect the wild-type sequence of the CYP2D7 pseudogene. The aim of this study was to identify the mechanism causing false-positive CYP2D6 (*) 15 calls and remediate those by redesigning and validating alternative TaqMan genotype assays. Among 13,866 DNA samples genotyped by the CompanionDx® lab on the OpenArray platform, 70 samples were identified as heterozygotes for 137Tins, the key SNP of CYP2D6 (*) 15. However, only 15 samples were confirmed when tested with the Luminex xTAG CYP2D6 Kit and sequencing of CYP2D6-specific long range (XL)-PCR products. Genotype and gene resequencing of CYP2D6 and CYP2D7-specific XL-PCR products revealed a CC>GT dinucleotide SNP in exon 1 of CYP2D7 that reverts the sequence to CYP2D6 and allows a TaqMan assay PCR primer to bind. Because CYP2D7 also carries a Tins, a false-positive mutation signal is generated. This CYP2D7 SNP was also responsible for generating false-positive signals for rs769258 (CYP2D6 (*) 35) which is also located in exon 1. Although alternative CYP2D6 (*) 15 and (*) 35 assays resolved the issue, we discovered a novel CYP2D6 (*) 15 subvariant in one sample that carries additional SNPs preventing detection with the alternate assay. The frequency of CYP2D6 (*) 15 was 0.1% in this ethnically diverse U.S. population sample. In addition, we also discovered linkage between the CYP2D7 CC>GT dinucleotide SNP and the 77G>A (rs28371696) SNP of CYP2D6 (*) 43. The frequency of this tentatively functional allele was 0.2%. Taken together, these findings emphasize that regardless of how careful genotyping assays are designed and evaluated before being commercially marketed, rare or unknown SNPs underneath primer
Residual lens effects in 2D mode of auto-stereoscopic lenticular-based switchable 2D/3D displays
NASA Astrophysics Data System (ADS)
Sluijter, M.; IJzerman, W. L.; de Boer, D. K. G.; de Zwart, S. T.
2006-04-01
We discuss residual lens effects in multi-view switchable auto-stereoscopic lenticular-based 2D/3D displays. With the introduction of a switchable lenticular, it is possible to switch between a 2D mode and a 3D mode. The 2D mode displays conventional content, whereas the 3D mode provides the sensation of depth to the viewer. The uniformity of a display in the 2D mode is quantified by the quality parameter modulation depth. In order to reduce the modulation depth in the 2D mode, birefringent lens plates are investigated analytically and numerically, by ray tracing. We can conclude that the modulation depth in the 2D mode can be substantially decreased by using birefringent lens plates with a perfect index match between lens material and lens plate. Birefringent lens plates do not disturb the 3D performance of a switchable 2D/3D display.
Differential CYP 2D6 metabolism alters primaquine pharmacokinetics.
Potter, Brittney M J; Xie, Lisa H; Vuong, Chau; Zhang, Jing; Zhang, Ping; Duan, Dehui; Luong, Thu-Lan T; Bandara Herath, H M T; Dhammika Nanayakkara, N P; Tekwani, Babu L; Walker, Larry A; Nolan, Christina K; Sciotti, Richard J; Zottig, Victor E; Smith, Philip L; Paris, Robert M; Read, Lisa T; Li, Qigui; Pybus, Brandon S; Sousa, Jason C; Reichard, Gregory A; Marcsisin, Sean R
2015-04-01
Primaquine (PQ) metabolism by the cytochrome P450 (CYP) 2D family of enzymes is required for antimalarial activity in both humans (2D6) and mice (2D). Human CYP 2D6 is highly polymorphic, and decreased CYP 2D6 enzyme activity has been linked to decreased PQ antimalarial activity. Despite the importance of CYP 2D metabolism in PQ efficacy, the exact role that these enzymes play in PQ metabolism and pharmacokinetics has not been extensively studied in vivo. In this study, a series of PQ pharmacokinetic experiments were conducted in mice with differential CYP 2D metabolism characteristics, including wild-type (WT), CYP 2D knockout (KO), and humanized CYP 2D6 (KO/knock-in [KO/KI]) mice. Plasma and liver pharmacokinetic profiles from a single PQ dose (20 mg/kg of body weight) differed significantly among the strains for PQ and carboxy-PQ. Additionally, due to the suspected role of phenolic metabolites in PQ efficacy, these were probed using reference standards. Levels of phenolic metabolites were highest in mice capable of metabolizing CYP 2D6 substrates (WT and KO/KI 2D6 mice). PQ phenolic metabolites were present in different quantities in the two strains, illustrating species-specific differences in PQ metabolism between the human and mouse enzymes. Taking the data together, this report furthers understanding of PQ pharmacokinetics in the context of differential CYP 2D metabolism and has important implications for PQ administration in humans with different levels of CYP 2D6 enzyme activity.
Mechanical characterization of 2D, 2D stitched, and 3D braided/RTM materials
NASA Technical Reports Server (NTRS)
Deaton, Jerry W.; Kullerd, Susan M.; Portanova, Marc A.
1993-01-01
Braided composite materials have potential for application in aircraft structures. Fuselage frames, floor beams, wing spars, and stiffeners are examples where braided composites could find application if cost effective processing and damage tolerance requirements are met. Another important consideration for braided composites relates to their mechanical properties and how they compare to the properties of composites produced by other textile composite processes being proposed for these applications. Unfortunately, mechanical property data for braided composites do not appear extensively in the literature. Data are presented in this paper on the mechanical characterization of 2D triaxial braid, 2D triaxial braid plus stitching, and 3D (through-the-thickness) braid composite materials. The braided preforms all had the same graphite tow size and the same nominal braid architectures, (+/- 30 deg/0 deg), and were resin transfer molded (RTM) using the same mold for each of two different resin systems. Static data are presented for notched and unnotched tension, notched and unnotched compression, and compression after impact strengths at room temperature. In addition, some static results, after environmental conditioning, are included. Baseline tension and compression fatigue results are also presented, but only for the 3D braided composite material with one of the resin systems.
Texture synthesis and classification using fractional lower order moments
NASA Astrophysics Data System (ADS)
Kulkarni, Anita; Chouikha, Mohamed F.
1995-03-01
Fractional lower order moments (FLOMs) based on the non-Gaussian stable distribution are employed for texture classification and synthesis. The parameters of a 2D autoregression model are estimated using the fractional lower order moments, and these parameters are used for texture classification. The analysis of FLOMs is useful when the variance of the underlying distribution is not finite and thus when the whole second-order statistics theory fails; hence, parameter estimation using FLOMs gives a more robust model over the existing methods that use autocorrelation function. This stable distribution is used in the synthesis of texture, and the performance of FLOMs and the autocorrelation methods are compared. By extensive simulations it is shown that the FLOM-based feature extraction algorithm outperforms the autocorrelation-based one.
A nonmagnetic impurity in a 2D quantum critical antiferromagnet
NASA Astrophysics Data System (ADS)
Troyer, Matthias
2003-03-01
We compute the properties of a mobile hole and a static impurity injected into a two-dimensional antiferromagnet or superconductor in the vicinity of a magnetic quantum critical point. A static S=1/2 impurity doped into a quantum-disordered spin gap system induces a local moment with spin S=1/2 and a corresponding Curie-like impurity susceptibility, while the same impurity in a Néel ordered state only gives a finite impurity susceptibility. For the quantum critical system however an interesting field-theoretical prediction has been made that there the impurity spin susceptibility still has a Curie-like divergence, but with a universal effective spin that is neither an integer nor a half-odd integer [1]. In large-scale quantum Monte Carlo (QMC) simulations using the loop algorithm we calculate the impurity susceptibility and find that, unfortunately, this effect is not observable since the renormalization of the effective spin away from S=1/2 is minimal. Other predictions of the field theory, such as a new critical exponent η' describing the time-dependent impurity spin correlations can however be confirmed [2]. Next we compute the spectral function of a hole injected into a 2D antiferromagnet or superconductor in the vicinity of a magnetic quantum critical point [3]. We show that, near van Hove singularities, the problem maps onto that of a static vacancy. This allows the calculation of the spectral function in a QMC simulation without encountering the negative sign problem. We find a vanishing quasiparticle residue at the critical point, a new exponent η_h0.080.04 describing the frequency dependence of the spectral function G_h(ω)(ɛ_0-ω)-1+ηh and discuss possible relevance to photoemission spectra of cuprate superconductors near the antinodal points. ^1 S. Sachdev, C. Buragohain and M. Vojta, Science 286, 2479 (1999). ^2 M. Troyer, in Prog. Theor. Phys. Suppl. 145 (2002); M. Körner and M. Troyer, ibid. ^3 S. Sachdev, M. Troyer, and M. Vojta, Phys. Rev
Salhi, A; Rainò, G; Fortunato, L; Tasco, V; Martiradonna, L; Todaro, M T; De Giorgi, M; Cingolani, R; Passaseo, A; Luna, E; Trampert, A; De Vittorio, M
2008-07-09
The authors have recently demonstrated the enhancement of the quantum dot laser modal gain, linearly scaling with the number of stacked QD layers. These results allowed the achievement of multi-quantum dot (MQD) lasers, the zero-dimensional counterpart of MQW lasers, with a modal gain as high as 42 cm(-1), in a seven-layer structure. A detailed investigation of the structural and optical properties was performed on laser structures with three, five and seven QD layers. Such an investigation clearly shows that the high uniformity of QD layer features is responsible for the linear increase of the modal gain and its high value.
Computational Screening of 2D Materials for Photocatalysis.
Singh, Arunima K; Mathew, Kiran; Zhuang, Houlong L; Hennig, Richard G
2015-03-19
Two-dimensional (2D) materials exhibit a range of extraordinary electronic, optical, and mechanical properties different from their bulk counterparts with potential applications for 2D materials emerging in energy storage and conversion technologies. In this Perspective, we summarize the recent developments in the field of solar water splitting using 2D materials and review a computational screening approach to rapidly and efficiently discover more 2D materials that possess properties suitable for solar water splitting. Computational tools based on density-functional theory can predict the intrinsic properties of potential photocatalyst such as their electronic properties, optical absorbance, and solubility in aqueous solutions. Computational tools enable the exploration of possible routes to enhance the photocatalytic activity of 2D materials by use of mechanical strain, bias potential, doping, and pH. We discuss future research directions and needed method developments for the computational design and optimization of 2D materials for photocatalysis.
Synthetic Covalent and Non-Covalent 2D Materials.
Boott, Charlotte E; Nazemi, Ali; Manners, Ian
2015-11-16
The creation of synthetic 2D materials represents an attractive challenge that is ultimately driven by their prospective uses in, for example, electronics, biomedicine, catalysis, sensing, and as membranes for separation and filtration. This Review illustrates some recent advances in this diverse field with a focus on covalent and non-covalent 2D polymers and frameworks, and self-assembled 2D materials derived from nanoparticles, homopolymers, and block copolymers.
Moment tensor mechanisms from Iberia
NASA Astrophysics Data System (ADS)
Stich, D.; Morales, J.
2003-12-01
New moment tensor solutions are presented for small and moderate earthquakes in Spain, Portugal and the westernmost Mediterranean Sea for the period from 2002 to present. Moment tensor inversion, to estimate focal mechanism, depth and magnitude, is applied at the Instituto Andaluz de Geof¡sica (IAG) in a routine manner to regional earthquakes with local magnitude larger then or equal 3.5. Recent improvements of broadband network coverage contribute to relatively high rates of success: Since beginning of 2002, we could obtain valuable solutions, in the sense that moment tensor synthetic waveforms fit adequately the main characteristics of the observed seismograms, for about 50% of all events of the initial selection. Results are available on-line at http://www.ugr.es/~iag/tensor/. To date, the IAG moment tensor catalogue contains 90 solutions since 1984 and gives a relatively detailed picture of seismotectonics in the Ibero-maghrebian region, covering also low seismicity areas like intraplate Iberia. Solutions are concentrated in southern Spain and the Alboran Sea along the diffuse African-Eurasian plate boundary. These solutions reveal characteristics of the transition between the reverse faulting regime in Algeria and predominately normal faulting on the Iberian Peninsula. Further we discuss the available mechanisms for intermediate deep events, related to subcrustal tectonic processes at the plate contact.
Unteachable Moments and Pedagogical Relationships
ERIC Educational Resources Information Center
Wang, Hongyu
2016-01-01
This paper discusses how Julia Kristeva's theory can inform our understanding of unteachable moments. It proposes a pedagogical relationship that can contain breakdowns of meanings and work toward breakthroughs to new awareness, particularly related to social justice pedagogy in teacher education. First, one example from the author's own teaching…
Moment generation in wheelchair propulsion.
Guo, Lan-Yuen; Zhao, K D; Su, Fong-Chin; An, Kai-Nan
2003-01-01
Wheelchair propulsion is a man machine interaction in which chair design and fit affect the relative positions and orientations of the upper extremity relative to the handrim and wheel axle. To understand these relationships better, experimental data were collected in five hand positions from five subjects exerting maximal effort to propel an instrumented wheelchair with its wheel in a locked position. The results of experiments revealed that the progression moment was greater at both initial and terminal propulsion positions and smaller in the mid-propulsion position. The vertical and horizontal force components were directed radially away from the wheel axle posterior to the dead centre position and radially towards the wheel axle anterior to top dead centre. Subsequently, a subject-specific quasi-static model of the upper extremity which maximized wheel progression moment was developed to augment our understanding of experimental measures. Model-predicted trends in progression moments and hand force direction were similar to experiment. Model predictions revealed that the optimal progression moment generation could potentially be affected by an individual's anthropometric parameters, joint strengths and also the direction of force applied by the hand on the handrim. Through wheelchair fitting and training of wheelchair users, it may be possible to improve propulsion technique.
Elliott, Mark A.; Giersch, Anne
2016-01-01
There has been evidence for the very brief, temporal quantization of perceptual experience at regular intervals below 100 ms for several decades. We briefly describe how earlier studies led to the concept of “psychological moment” of between 50 and 60 ms duration. According to historical theories, within the psychological moment all events would be processed as co-temporal. More recently, a link with physiological mechanisms has been proposed, according to which the 50–60 ms psychological moment would be defined by the upper limit required by neural mechanisms to synchronize and thereby represent a snapshot of current perceptual event structure. However, our own experimental developments also identify a more fine-scaled, serialized process structure within the psychological moment. Our data suggests that not all events are processed as co-temporal within the psychological moment and instead, some are processed successively. This evidence questions the analog relationship between synchronized process and simultaneous experience and opens debate on the ontology and function of “moments” in psychological experience. PMID:26779059
NASA Astrophysics Data System (ADS)
Miller, Arthur I.; Williams, Paul; Palmer, Tim; O'Shea, Michael; Neale, Ron; Reed, Cameron
2016-11-01
In October Philip Ball reported on the “Physics Imagination Retreat” workshop held in June at the University of Cambridge in the UK, at which a number of prominent scientists recounted their moments of sudden insight that led to scientific discoveries.
Measuring the Moment of Inertia
ERIC Educational Resources Information Center
Lehmberg, George L.
1978-01-01
Two physics experiments are described, One, involving a laboratory cart accelerated along a level surface, examines the concept of inertial mass in translation and the other, using a solid cylinder, measures the moment of inertia of a wheel. Equations and illustrations are included. (MA)
Moment of Inertia by Differentiation
ERIC Educational Resources Information Center
Rizcallah, Joseph A.
2015-01-01
The calculation of the moment of inertia of an extended body, as presented in standard introductory-level textbooks, involves the evaluation of a definite integral--an operation often not fully mastered by beginners, let alone the conceptual difficulties it presents, even to the advanced student, in understanding and setting up the integral in the…
Epitaxial 2D SnSe2/ 2D WSe2 van der Waals Heterostructures.
Aretouli, Kleopatra Emmanouil; Tsoutsou, Dimitra; Tsipas, Polychronis; Marquez-Velasco, Jose; Aminalragia Giamini, Sigiava; Kelaidis, Nicolaos; Psycharis, Vassilis; Dimoulas, Athanasios
2016-09-07
van der Waals heterostructures of 2D semiconductor materials can be used to realize a number of (opto)electronic devices including tunneling field effect devices (TFETs). It is shown in this work that high quality SnSe2/WSe2 vdW heterostructure can be grown by molecular beam epitaxy on AlN(0001)/Si(111) substrates using a Bi2Se3 buffer layer. A valence band offset of 0.8 eV matches the energy gap of SnSe2 in such a way that the VB edge of WSe2 and the CB edge of SnSe2 are lined up, making this materials combination suitable for (nearly) broken gap TFETs.
NASA Astrophysics Data System (ADS)
Magarill, L. I.; Entin, M. V.
2016-12-01
The electron absorption and the edge photocurrent of a 2D topological insulator are studied for transitions between edge states to 2D states. The circular polarized light is found to produce the edge photocurrent, the direction of which is determined by light polarization and edge orientation. It is shown that the edge-state current is found to exceed the 2D current owing to the topological protection of the edge states.
Zhong, Liyun; Zeng, Gucheng; Lu, Xiaoxu; Wang, Richard C; Gong, Guangming; Yan, Lin; Huang, Dan; Chen, Zheng W
2009-06-17
Direct molecular imaging of nano-spatial relationship between T cell receptor (TCR)/CD3 and CD4 or CD8 co-receptor before and after activation of a primary T cell has not been reported. We have recently innovated application of near-field scanning optical microscopy (NSOM) and immune-labeling quantum dots (QD) to image Ag-specific TCR response during in vivo clonal expansion, and now up-graded the NSOM/QD-based nanotechnology through dipole-polarization and dual-color imaging. Using this imaging system scanning cell-membrane molecules at a best-optical lateral resolution, we demonstrated that CD3, CD4 or CD8 molecules were distinctly distributed as single QD-bound molecules or nano-clusters equivalent to 2-4 QD fluorescence-intensity/size on cell-membrane of un-stimulated primary T cells, and approximately 6-10% of CD3 were co-clustering with CD4 or CD8 as 70-110 nm nano-clusters without forming nano-domains. The ligation of TCR/CD3 on CD4 or CD8 T cells led to CD3 nanoscale co-clustering or interaction with CD4 or CD8 co-receptors forming 200-500 nm nano-domains or >500 nm micro-domains. Such nano-spatial co-clustering of CD3 and CD4 or CD3 and CD8 appeared to be an intrinsic event of TCR/CD3 ligation, not purely limited to MHC engagement, and be driven by Lck phosphorylation. Importantly, CD28 co-stimulation remarkably enhanced TCR/CD3 nanoscale co-clustering or interaction with CD4 co-receptor within nano- or micro-domains on the membrane. In contrast, CD28 co-stimulation did not enhance CD8 clustering or CD3-CD8 co-clustering in nano-domains although it increased molecular number and density of CD3 clustering in the enlarged nano-domains. These nanoscale findings provide new insights into TCR/CD3 interaction with CD4 or CD8 co-receptor in T-cell activation.
Energy Efficiency of D2D Multi-User Cooperation.
Zhang, Zufan; Wang, Lu; Zhang, Jie
2017-03-28
The Device-to-Device (D2D) communication system is an important part of heterogeneous networks. It has great potential to improve spectrum efficiency, throughput and energy efficiency cooperation of multiple D2D users with the advantage of direct communication. When cooperating, D2D users expend extraordinary energy to relay data to other D2D users. Hence, the remaining energy of D2D users determines the life of the system. This paper proposes a cooperation scheme for multiple D2D users who reuse the orthogonal spectrum and are interested in the same data by aiming to solve the energy problem of D2D users. Considering both energy availability and the Signal to Noise Ratio (SNR) of each D2D user, the Kuhn-Munkres algorithm is introduced in the cooperation scheme to solve relay selection problems. Thus, the cooperation issue is transformed into a maximum weighted matching (MWM) problem. In order to enhance energy efficiency without the deterioration of Quality of Service (QoS), the link outage probability is derived according to the Shannon Equation by considering the data rate and delay. The simulation studies the relationships among the number of cooperative users, the length of shared data, the number of data packets and energy efficiency.
Integrating Mobile Multimedia into Textbooks: 2D Barcodes
ERIC Educational Resources Information Center
Uluyol, Celebi; Agca, R. Kagan
2012-01-01
The major goal of this study was to empirically compare text-plus-mobile phone learning using an integrated 2D barcode tag in a printed text with three other conditions described in multimedia learning theory. The method examined in the study involved modifications of the instructional material such that: a 2D barcode was used near the text, the…
Efficient Visible Quasi-2D Perovskite Light-Emitting Diodes.
Byun, Jinwoo; Cho, Himchan; Wolf, Christoph; Jang, Mi; Sadhanala, Aditya; Friend, Richard H; Yang, Hoichang; Lee, Tae-Woo
2016-09-01
Efficient quasi-2D-structure perovskite light-emitting diodes (4.90 cd A(-1) ) are demonstrated by mixing a 3D-structured perovskite material (methyl ammonium lead bromide) and a 2D-structured perovskite material (phenylethyl ammonium lead bromide), which can be ascribed to better film uniformity, enhanced exciton confinement, and reduced trap density.
Adaptation algorithms for 2-D feedforward neural networks.
Kaczorek, T
1995-01-01
The generalized weight adaptation algorithms presented by J.G. Kuschewski et al. (1993) and by S.H. Zak and H.J. Sira-Ramirez (1990) are extended for 2-D madaline and 2-D two-layer feedforward neural nets (FNNs).
Regulation of ligands for the NKG2D activating receptor
Raulet, David H.; Gasser, Stephan; Gowen, Benjamin G.; Deng, Weiwen; Jung, Heiyoun
2014-01-01
NKG2D is an activating receptor expressed by all NK cells and subsets of T cells. It serves as a major recognition receptor for detection and elimination of transformed and infected cells and participates in the genesis of several inflammatory diseases. The ligands for NKG2D are self-proteins that are induced by pathways that are active in certain pathophysiological states. NKG2D ligands are regulated transcriptionally, at the level of mRNA and protein stability, and by cleavage from the cell surface. In some cases, ligand induction can be attributed to pathways that are activated specifically in cancer cells or infected cells. We review the numerous pathways that have been implicated in the regulation of NKG2D ligands, discuss the pathologic states in which those pathways are likely to act, and attempt to synthesize the findings into general schemes of NKG2D ligand regulation in NK cell responses to cancer and infection. PMID:23298206
2D materials and van der Waals heterostructures.
Novoselov, K S; Mishchenko, A; Carvalho, A; Castro Neto, A H
2016-07-29
The physics of two-dimensional (2D) materials and heterostructures based on such crystals has been developing extremely fast. With these new materials, truly 2D physics has begun to appear (for instance, the absence of long-range order, 2D excitons, commensurate-incommensurate transition, etc.). Novel heterostructure devices--such as tunneling transistors, resonant tunneling diodes, and light-emitting diodes--are also starting to emerge. Composed from individual 2D crystals, such devices use the properties of those materials to create functionalities that are not accessible in other heterostructures. Here we review the properties of novel 2D crystals and examine how their properties are used in new heterostructure devices.
New generation transistor technologies enabled by 2D crystals
NASA Astrophysics Data System (ADS)
Jena, D.
2013-05-01
The discovery of graphene opened the door to 2D crystal materials. The lack of a bandgap in 2D graphene makes it unsuitable for electronic switching transistors in the conventional field-effect sense, though possible techniques exploiting the unique bandstructure and nanostructures are being explored. The transition metal dichalcogenides have 2D crystal semiconductors, which are well-suited for electronic switching. We experimentally demonstrate field effect transistors with current saturation and carrier inversion made from layered 2D crystal semiconductors such as MoS2, WS2, and the related family. We also evaluate the feasibility of such semiconducting 2D crystals for tunneling field effect transistors for low-power digital logic. The article summarizes the current state of new generation transistor technologies either proposed, or demonstrated, with a commentary on the challenges and prospects moving forward.
Estrogen-Induced Cholestasis Leads to Repressed CYP2D6 Expression in CYP2D6-Humanized Mice.
Pan, Xian; Jeong, Hyunyoung
2015-07-01
Cholestasis activates bile acid receptor farnesoid X receptor (FXR) and subsequently enhances hepatic expression of small heterodimer partner (SHP). We previously demonstrated that SHP represses the transactivation of cytochrome P450 2D6 (CYP2D6) promoter by hepatocyte nuclear factor (HNF) 4α. In this study, we investigated the effects of estrogen-induced cholestasis on CYP2D6 expression. Estrogen-induced cholestasis occurs in subjects receiving estrogen for contraception or hormone replacement, or in susceptible women during pregnancy. In CYP2D6-humanized transgenic (Tg-CYP2D6) mice, cholestasis triggered by administration of 17α-ethinylestradiol (EE2) at a high dose led to 2- to 3-fold decreases in CYP2D6 expression. This was accompanied by increased hepatic SHP expression and subsequent decreases in the recruitment of HNF4α to CYP2D6 promoter. Interestingly, estrogen-induced cholestasis also led to increased recruitment of estrogen receptor (ER) α, but not that of FXR, to Shp promoter, suggesting a predominant role of ERα in transcriptional regulation of SHP in estrogen-induced cholestasis. EE2 at a low dose (that does not cause cholestasis) also increased SHP (by ∼ 50%) and decreased CYP2D6 expression (by 1.5-fold) in Tg-CYP2D6 mice, the magnitude of differences being much smaller than that shown in EE2-induced cholestasis. Taken together, our data indicate that EE2-induced cholestasis increases SHP and represses CYP2D6 expression in Tg-CYP2D6 mice in part through ERα transactivation of Shp promoter.
Superconductivity from Emerging Magnetic Moments.
Hoshino, Shintaro; Werner, Philipp
2015-12-11
Multiorbital Hubbard models are shown to exhibit a spatially isotropic spin-triplet superconducting phase, where equal-spin electrons in different local orbitals are paired. This superconducting state is stabilized in the spin-freezing crossover regime, where local moments emerge in the metal phase, and the pairing is substantially assisted by spin anisotropy. The phase diagram features a superconducting dome below a non-Fermi-liquid metallic region and next to a magnetically ordered phase. We suggest that this type of fluctuating-moment-induced superconductivity, which is not originating from fluctuations near a quantum critical point, may be realized in spin-triplet superconductors such as strontium ruthenates and uranium compounds.
Xie, Donghao; Ji, Ding-Kun; Zhang, Yue; Cao, Jun; Zheng, Hu; Liu, Lin; Zang, Yi; Li, Jia; Chen, Guo-Rong; James, Tony D; He, Xiao-Peng
2016-08-04
Here we demonstrate that 2D MoS2 can enhance the receptor-targeting and imaging ability of a fluorophore-labelled ligand. The 2D MoS2 has an enhanced working concentration range when compared with graphene oxide, resulting in the improved imaging of both cell and tissue samples.
Efficient 2D MRI relaxometry using compressed sensing
NASA Astrophysics Data System (ADS)
Bai, Ruiliang; Cloninger, Alexander; Czaja, Wojciech; Basser, Peter J.
2015-06-01
Potential applications of 2D relaxation spectrum NMR and MRI to characterize complex water dynamics (e.g., compartmental exchange) in biology and other disciplines have increased in recent years. However, the large amount of data and long MR acquisition times required for conventional 2D MR relaxometry limits its applicability for in vivo preclinical and clinical MRI. We present a new MR pipeline for 2D relaxometry that incorporates compressed sensing (CS) as a means to vastly reduce the amount of 2D relaxation data needed for material and tissue characterization without compromising data quality. Unlike the conventional CS reconstruction in the Fourier space (k-space), the proposed CS algorithm is directly applied onto the Laplace space (the joint 2D relaxation data) without compressing k-space to reduce the amount of data required for 2D relaxation spectra. This framework is validated using synthetic data, with NMR data acquired in a well-characterized urea/water phantom, and on fixed porcine spinal cord tissue. The quality of the CS-reconstructed spectra was comparable to that of the conventional 2D relaxation spectra, as assessed using global correlation, local contrast between peaks, peak amplitude and relaxation parameters, etc. This result brings this important type of contrast closer to being realized in preclinical, clinical, and other applications.
2D vs. 3D mammography observer study
NASA Astrophysics Data System (ADS)
Fernandez, James Reza F.; Hovanessian-Larsen, Linda; Liu, Brent
2011-03-01
Breast cancer is the most common type of non-skin cancer in women. 2D mammography is a screening tool to aid in the early detection of breast cancer, but has diagnostic limitations of overlapping tissues, especially in dense breasts. 3D mammography has the potential to improve detection outcomes by increasing specificity, and a new 3D screening tool with a 3D display for mammography aims to improve performance and efficiency as compared to 2D mammography. An observer study using a mammography phantom was performed to compare traditional 2D mammography with this ne 3D mammography technique. In comparing 3D and 2D mammography there was no difference in calcification detection, and mass detection was better in 2D as compared to 3D. There was a significant decrease in reading time for masses, calcifications, and normals in 3D compared to 2D, however, as well as more favorable confidence levels in reading normal cases. Given the limitations of the mammography phantom used, however, a clearer picture in comparing 3D and 2D mammography may be better acquired with the incorporation of human studies in the future.
Wei, Hongjiang; Zhang, Yuyao; Gibbs, Eric; Chen, Nan-Kuei; Wang, Nian; Liu, Chunlei
2017-04-01
Quantitative susceptibility mapping (QSM) measures tissue magnetic susceptibility and typically relies on time-consuming three-dimensional (3D) gradient-echo (GRE) MRI. Recent studies have shown that two-dimensional (2D) multi-slice gradient-echo echo-planar imaging (GRE-EPI), which is commonly used in functional MRI (fMRI) and other dynamic imaging techniques, can also be used to produce data suitable for QSM with much shorter scan times. However, the production of high-quality QSM maps is difficult because data obtained by 2D multi-slice scans often have phase inconsistencies across adjacent slices and strong susceptibility field gradients near air-tissue interfaces. To address these challenges in 2D EPI-based QSM studies, we present a new data processing procedure that integrates 2D and 3D phase processing. First, 2D Laplacian-based phase unwrapping and 2D background phase removal are performed to reduce phase inconsistencies between slices and remove in-plane harmonic components of the background phase. This is followed by 3D background phase removal for the through-plane harmonic components. The proposed phase processing was evaluated with 2D EPI data obtained from healthy volunteers, and compared against conventional 3D phase processing using the same 2D EPI datasets. Our QSM results were also compared with QSM values from time-consuming 3D GRE data, which were taken as ground truth. The experimental results show that this new 2D EPI-based QSM technique can produce quantitative susceptibility measures that are comparable with those of 3D GRE-based QSM across different brain regions (e.g. subcortical iron-rich gray matter, cortical gray and white matter). This new 2D EPI QSM reconstruction method is implemented within STI Suite, which is a comprehensive shareware for susceptibility imaging and quantification. Copyright © 2016 John Wiley & Sons, Ltd.
NKG2D receptor and its ligands in host defense
Lanier, Lewis L.
2015-01-01
NKG2D is an activating receptor expressed on the surface of natural killer (NK) cells, CD8+ T cells, and subsets of CD4+ T cells, iNKT cells, and γδ T cells. In humans NKG2D transmits signals by its association with the DAP10 adapter subunit and in mice alternatively spliced isoforms transmit signals either using DAP10 or DAP12 adapter subunits. Although NKG2D is encoded by a highly conserved gene (KLRK1) with limited polymorphism, the receptor recognizes an extensive repertoire of ligands, encoded by at least 8 genes in humans (MICA, MICB, RAET1E, RAET1G, RAET1H, RAET1I, RAET1L, and RAET1N), some with extensive allelic polymorphism. Expression of the NKG2D ligands is tightly regulated at the level of transcription, translation, and post-translation. In general healthy adult tissues do not express NKG2D glycoproteins on the cell surface, but these ligands can be induced by hyper-proliferation and transformation, as well as when cells are infected by pathogens. Thus, the NKG2D pathway serves a mechanism for the immune system to detect and eliminate cells that have undergone “stress”. Viruses and tumor cells have devised numerous strategies to evade detection by the NKG2D surveillance system and diversification of the NKG2D ligand genes likely has been driven by selective pressures imposed by pathogens. NKG2D provides an attractive target for therapeutics in the treatment of infectious diseases, cancer, and autoimmune diseases. PMID:26041808
NKG2D Receptor and Its Ligands in Host Defense.
Lanier, Lewis L
2015-06-01
NKG2D is an activating receptor expressed on the surface of natural killer (NK) cells, CD8(+) T cells, and subsets of CD4(+) T cells, invariant NKT cells (iNKT), and γδ T cells. In humans, NKG2D transmits signals by its association with the DAP10 adapter subunit, and in mice alternatively spliced isoforms transmit signals either using DAP10 or DAP12 adapter subunits. Although NKG2D is encoded by a highly conserved gene (KLRK1) with limited polymorphism, the receptor recognizes an extensive repertoire of ligands, encoded by at least eight genes in humans (MICA, MICB, RAET1E, RAET1G, RAET1H, RAET1I, RAET1L, and RAET1N), some with extensive allelic polymorphism. Expression of the NKG2D ligands is tightly regulated at the level of transcription, translation, and posttranslation. In general, healthy adult tissues do not express NKG2D glycoproteins on the cell surface, but these ligands can be induced by hyperproliferation and transformation, as well as when cells are infected by pathogens. Thus, the NKG2D pathway serves as a mechanism for the immune system to detect and eliminate cells that have undergone "stress." Viruses and tumor cells have devised numerous strategies to evade detection by the NKG2D surveillance system, and diversification of the NKG2D ligand genes likely has been driven by selective pressures imposed by pathogens. NKG2D provides an attractive target for therapeutics in the treatment of infectious diseases, cancer, and autoimmune diseases.
2-D Versus 3-D Magnetotelluric Data Interpretation
NASA Astrophysics Data System (ADS)
Ledo, Juanjo
2005-09-01
In recent years, the number of publications dealing with the mathematical and physical 3-D aspects of the magnetotelluric method has increased drastically. However, field experiments on a grid are often impractical and surveys are frequently restricted to single or widely separated profiles. So, in many cases we find ourselves with the following question: is the applicability of the 2-D hypothesis valid to extract geoelectric and geological information from real 3-D environments? The aim of this paper is to explore a few instructive but general situations to understand the basics of a 2-D interpretation of 3-D magnetotelluric data and to determine which data subset (TE-mode or TM-mode) is best for obtaining the electrical conductivity distribution of the subsurface using 2-D techniques. A review of the mathematical and physical fundamentals of the electromagnetic fields generated by a simple 3-D structure allows us to prioritise the choice of modes in a 2-D interpretation of responses influenced by 3-D structures. This analysis is corroborated by numerical results from synthetic models and by real data acquired by other authors. One important result of this analysis is that the mode most unaffected by 3-D effects depends on the position of the 3-D structure with respect to the regional 2-D strike direction. When the 3-D body is normal to the regional strike, the TE-mode is affected mainly by galvanic effects, while the TM-mode is affected by galvanic and inductive effects. In this case, a 2-D interpretation of the TM-mode is prone to error. When the 3-D body is parallel to the regional 2-D strike the TE-mode is affected by galvanic and inductive effects and the TM-mode is affected mainly by galvanic effects, making it more suitable for 2-D interpretation. In general, a wise 2-D interpretation of 3-D magnetotelluric data can be a guide to a reasonable geological interpretation.
Nuclear Quadrupole Moments and Nuclear Shell Structure
DOE R&D Accomplishments Database
Townes, C. H.; Foley, H. M.; Low, W.
1950-06-23
Describes a simple model, based on nuclear shell considerations, which leads to the proper behavior of known nuclear quadrupole moments, although predictions of the magnitudes of some quadrupole moments are seriously in error.
Recent advances in 2D materials for photocatalysis.
Luo, Bin; Liu, Gang; Wang, Lianzhou
2016-04-07
Two-dimensional (2D) materials have attracted increasing attention for photocatalytic applications because of their unique thickness dependent physical and chemical properties. This review gives a brief overview of the recent developments concerning the chemical synthesis and structural design of 2D materials at the nanoscale and their applications in photocatalytic areas. In particular, recent progress on the emerging strategies for tailoring 2D material-based photocatalysts to improve their photo-activity including elemental doping, heterostructure design and functional architecture assembly is discussed.
Comparison of 2D and 3D gamma analyses
Pulliam, Kiley B.; Huang, Jessie Y.; Howell, Rebecca M.; Followill, David; Kry, Stephen F.; Bosca, Ryan; O’Daniel, Jennifer
2014-02-15
Purpose: As clinics begin to use 3D metrics for intensity-modulated radiation therapy (IMRT) quality assurance, it must be noted that these metrics will often produce results different from those produced by their 2D counterparts. 3D and 2D gamma analyses would be expected to produce different values, in part because of the different search space available. In the present investigation, the authors compared the results of 2D and 3D gamma analysis (where both datasets were generated in the same manner) for clinical treatment plans. Methods: Fifty IMRT plans were selected from the authors’ clinical database, and recalculated using Monte Carlo. Treatment planning system-calculated (“evaluated dose distributions”) and Monte Carlo-recalculated (“reference dose distributions”) dose distributions were compared using 2D and 3D gamma analysis. This analysis was performed using a variety of dose-difference (5%, 3%, 2%, and 1%) and distance-to-agreement (5, 3, 2, and 1 mm) acceptance criteria, low-dose thresholds (5%, 10%, and 15% of the prescription dose), and data grid sizes (1.0, 1.5, and 3.0 mm). Each comparison was evaluated to determine the average 2D and 3D gamma, lower 95th percentile gamma value, and percentage of pixels passing gamma. Results: The average gamma, lower 95th percentile gamma value, and percentage of passing pixels for each acceptance criterion demonstrated better agreement for 3D than for 2D analysis for every plan comparison. The average difference in the percentage of passing pixels between the 2D and 3D analyses with no low-dose threshold ranged from 0.9% to 2.1%. Similarly, using a low-dose threshold resulted in a difference between the mean 2D and 3D results, ranging from 0.8% to 1.5%. The authors observed no appreciable differences in gamma with changes in the data density (constant difference: 0.8% for 2D vs 3D). Conclusions: The authors found that 3D gamma analysis resulted in up to 2.9% more pixels passing than 2D analysis. It must
Defining moments in leadership character development.
Bleich, Michael R
2015-06-01
Critical moments in life define one's character and clarify true values. Reflective leadership is espoused as an important practice for transformational leaders. Professional development educators can help surface and explore defining moments, strengthen leadership behavior with defining moments as a catalyst for change, and create safe spaces for leaders to expand their leadership capacity.
The Wavelet Element Method. Part 2; Realization and Additional Features in 2D and 3D
NASA Technical Reports Server (NTRS)
Canuto, Claudio; Tabacco, Anita; Urban, Karsten
1998-01-01
The Wavelet Element Method (WEM) provides a construction of multiresolution systems and biorthogonal wavelets on fairly general domains. These are split into subdomains that are mapped to a single reference hypercube. Tensor products of scaling functions and wavelets defined on the unit interval are used on the reference domain. By introducing appropriate matching conditions across the interelement boundaries, a globally continuous biorthogonal wavelet basis on the general domain is obtained. This construction does not uniquely define the basis functions but rather leaves some freedom for fulfilling additional features. In this paper we detail the general construction principle of the WEM to the 1D, 2D and 3D cases. We address additional features such as symmetry, vanishing moments and minimal support of the wavelet functions in each particular dimension. The construction is illustrated by using biorthogonal spline wavelets on the interval.
A 2-D Implicit, Energy and Charge Conserving Particle In Cell Method
McPherson, Allen L.; Knoll, Dana A.; Cieren, Emmanuel B.; Feltman, Nicolas; Leibs, Christopher A.; McCarthy, Colleen; Murthy, Karthik S.; Wang, Yijie
2012-09-10
Recently, a fully implicit electrostatic 1D charge- and energy-conserving particle-in-cell algorithm was proposed and implemented by Chen et al ([2],[3]). Central to the algorithm is an advanced particle pusher. Particles are moved using an energy conserving scheme and are forced to stop at cell faces to conserve charge. Moreover, a time estimator is used to control errors in momentum. Here we implement and extend this advanced particle pusher to include 2D and electromagnetic fields. Derivations of all modifications made are presented in full. Special consideration is taken to ensure easy coupling into the implicit moment based method proposed by Taitano et al [19]. Focus is then given to optimizing the presented particle pusher on emerging architectures. Two multicore implementations, and one GPU (Graphics Processing Unit) implementation are discussed and analyzed.
Double resonance rotational spectroscopy of CH2D+
NASA Astrophysics Data System (ADS)
Töpfer, Matthias; Jusko, Pavol; Schlemmer, Stephan; Asvany, Oskar
2016-09-01
Context. Deuterated forms of CH are thought to be responsible for deuterium enrichment in lukewarm astronomical environments. There is no unambiguous detection of CH2D+ in space to date. Aims: Four submillimetre rotational lines of CH2D+ are documented in the literature. Our aim is to present a complete dataset of highly resolved rotational lines, including millimetre (mm) lines needed for a potential detection. Methods: We used a low-temperature ion trap and applied a novel IR-mm-wave double resonance method to measure the rotational lines of CH2D+. Results: We measured 21 low-lying (J ≤ 4) rotational transitions of CH2D+ between 23 GHz and 1.1 THz with accuracies close to 2 ppb.
Recovering 3D particle size distributions from 2D sections
NASA Astrophysics Data System (ADS)
Cuzzi, Jeffrey N.; Olson, Daniel M.
2017-03-01
We discuss different ways to convert observed, apparent particle size distributions from 2D sections (thin sections, SEM maps on planar surfaces, etc.) into true 3D particle size distributions. We give a simple, flexible, and practical method to do this; show which of these techniques gives the most faithful conversions; and provide (online) short computer codes to calculate both 2D-3D recoveries and simulations of 2D observations by random sectioning. The most important systematic bias of 2D sectioning, from the standpoint of most chondrite studies, is an overestimate of the abundance of the larger particles. We show that fairly good recoveries can be achieved from observed size distributions containing 100-300 individual measurements of apparent particle diameter.
Phonon thermal conduction in novel 2D materials
NASA Astrophysics Data System (ADS)
Xu, Xiangfan; Chen, Jie; Li, Baowen
2016-12-01
Recently, there has been increasing interest in phonon thermal transport in low-dimensional materials, due to the crucial importance of dissipating and managing heat in micro- and nano-electronic devices. Significant progress has been achieved for one-dimensional (1D) systems, both theoretically and experimentally. However, the study of heat conduction in two-dimensional (2D) systems is still in its infancy due to the limited availability of 2D materials and the technical challenges of fabricating suspended samples that are suitable for thermal measurements. In this review, we outline different experimental techniques and theoretical approaches for phonon thermal transport in 2D materials, discuss the problems and challenges of phonon thermal transport measurements and provide a comparison between existing experimental data. Special attention will be given to the effects of size, dimensionality, anisotropy and mode contributions in novel 2D systems, including graphene, boron nitride, MoS2, black phosphorous and silicene.
Recent developments in 2D layered inorganic nanomaterials for sensing
NASA Astrophysics Data System (ADS)
Kannan, Padmanathan Karthick; Late, Dattatray J.; Morgan, Hywel; Rout, Chandra Sekhar
2015-08-01
Two dimensional layered inorganic nanomaterials (2D-LINs) have recently attracted huge interest because of their unique thickness dependent physical and chemical properties and potential technological applications. The properties of these layered materials can be tuned via both physical and chemical processes. Some 2D layered inorganic nanomaterials like MoS2, WS2 and SnS2 have been recently developed and employed in various applications, including new sensors because of their layer-dependent electrical properties. This article presents a comprehensive overview of recent developments in the application of 2D layered inorganic nanomaterials as sensors. Some of the salient features of 2D materials for different sensing applications are discussed, including gas sensing, electrochemical sensing, SERS and biosensing, SERS sensing and photodetection. The working principles of the sensors are also discussed together with examples.
Phonon thermal conduction in novel 2D materials.
Xu, Xiangfan; Chen, Jie; Li, Baowen
2016-12-07
Recently, there has been increasing interest in phonon thermal transport in low-dimensional materials, due to the crucial importance of dissipating and managing heat in micro- and nano-electronic devices. Significant progress has been achieved for one-dimensional (1D) systems, both theoretically and experimentally. However, the study of heat conduction in two-dimensional (2D) systems is still in its infancy due to the limited availability of 2D materials and the technical challenges of fabricating suspended samples that are suitable for thermal measurements. In this review, we outline different experimental techniques and theoretical approaches for phonon thermal transport in 2D materials, discuss the problems and challenges of phonon thermal transport measurements and provide a comparison between existing experimental data. Special attention will be given to the effects of size, dimensionality, anisotropy and mode contributions in novel 2D systems, including graphene, boron nitride, MoS2, black phosphorous and silicene.
Exact Solution of Ising Model in 2d Shortcut Network
NASA Astrophysics Data System (ADS)
Shanker, O.
We give the exact solution to the Ising model in the shortcut network in the 2D limit. The solution is found by mapping the model to the square lattice model with Brascamp and Kunz boundary conditions.
Technical Review of the UNET2D Hydraulic Model
Perkins, William A.; Richmond, Marshall C.
2009-05-18
The Kansas City District of the US Army Corps of Engineers is engaged in a broad range of river management projects that require knowledge of spatially-varied hydraulic conditions such as velocities and water surface elevations. This information is needed to design new structures, improve existing operations, and assess aquatic habitat. Two-dimensional (2D) depth-averaged numerical hydraulic models are a common tool that can be used to provide velocity and depth information. Kansas City District is currently using a specific 2D model, UNET2D, that has been developed to meet the needs of their river engineering applications. This report documents a tech- nical review of UNET2D.
Reconstruction-based 3D/2D image registration.
Tomazevic, Dejan; Likar, Bostjan; Pernus, Franjo
2005-01-01
In this paper we present a novel 3D/2D registration method, where first, a 3D image is reconstructed from a few 2D X-ray images and next, the preoperative 3D image is brought into the best possible spatial correspondence with the reconstructed image by optimizing a similarity measure. Because the quality of the reconstructed image is generally low, we introduce a novel asymmetric mutual information similarity measure, which is able to cope with low image quality as well as with different imaging modalities. The novel 3D/2D registration method has been evaluated using standardized evaluation methodology and publicly available 3D CT, 3DRX, and MR and 2D X-ray images of two spine phantoms, for which gold standard registrations were known. In terms of robustness, reliability and capture range the proposed method outperformed the gradient-based method and the method based on digitally reconstructed radiographs (DRRs).
Alloyed 2D Metal-Semiconductor Atomic Layer Junctions.
Kim, Ah Ra; Kim, Yonghun; Nam, Jaewook; Chung, Hee-Suk; Kim, Dong Jae; Kwon, Jung-Dae; Park, Sang Won; Park, Jucheol; Choi, Sun Young; Lee, Byoung Hun; Park, Ji Hyeon; Lee, Kyu Hwan; Kim, Dong-Ho; Choi, Sung Mook; Ajayan, Pulickel M; Hahm, Myung Gwan; Cho, Byungjin
2016-03-09
Heterostructures of compositionally and electronically variant two-dimensional (2D) atomic layers are viable building blocks for ultrathin optoelectronic devices. We show that the composition of interfacial transition region between semiconducting WSe2 atomic layer channels and metallic NbSe2 contact layers can be engineered through interfacial doping with Nb atoms. WxNb1-xSe2 interfacial regions considerably lower the potential barrier height of the junction, significantly improving the performance of the corresponding WSe2-based field-effect transistor devices. The creation of such alloyed 2D junctions between dissimilar atomic layer domains could be the most important factor in controlling the electronic properties of 2D junctions and the design and fabrication of 2D atomic layer devices.
Dominant 2D magnetic turbulence in the solar wind
NASA Technical Reports Server (NTRS)
Bieber, John W.; Wanner, Wolfgang; Matthaeus, William H.
1995-01-01
There have been recent suggestions that solar wind magnetic turbulence may be a composite of slab geometry (wavevector aligned with the mean magnetic field) and 2D geometry (wavevectors perpendicular to the mean field). We report results of two new tests of this hypothesis using Helios measurements of inertial ranged magnetic spectra in the solar wind. The first test is based upon a characteristic difference between perpendicular and parallel reduced power spectra which is expected for the 2D component but not for the slab component. The second test examines the dependence of power spectrum density upon the magnetic field angle (i.e., the angle between the mean magnetic field and the radial direction), a relationship which is expected to be in opposite directions for the slab and 2D components. Both tests support the presence of a dominant (approximately 85 percent by energy) 2D component in solar wind magnetic turbulence.
Studying Zeolite Catalysts with a 2D Model System
Boscoboinik, Anibal
2016-12-07
Anibal Boscoboinik, a materials scientist at Brookhaven’s Center for Functional Nanomaterials, discusses the surface-science tools and 2D model system he uses to study catalysis in nanoporous zeolites, which catalyze reactions in many industrial processes.
ORION96. 2-d Finite Element Code Postprocessor
Sanford, L.A.; Hallquist, J.O.
1992-02-02
ORION is an interactive program that serves as a postprocessor for the analysis programs NIKE2D, DYNA2D, TOPAZ2D, and CHEMICAL TOPAZ2D. ORION reads binary plot files generated by the two-dimensional finite element codes currently used by the Methods Development Group at LLNL. Contour and color fringe plots of a large number of quantities may be displayed on meshes consisting of triangular and quadrilateral elements. ORION can compute strain measures, interface pressures along slide lines, reaction forces along constrained boundaries, and momentum. ORION has been applied to study the response of two-dimensional solids and structures undergoing finite deformations under a wide variety of large deformation transient dynamic and static problems and heat transfer analyses.
Emerging and potential opportunities for 2D flexible nanoelectronics
NASA Astrophysics Data System (ADS)
Zhu, Weinan; Park, Saungeun; Akinwande, Deji
2016-05-01
The last 10 years have seen the emergence of two-dimensional (2D) nanomaterials such as graphene, transition metal dichalcogenides (TMDs), and black phosphorus (BP) among the growing portfolio of layered van der Waals thin films. Graphene, the prototypical 2D material has advanced rapidly in device, circuit and system studies that has resulted in commercial large-area applications. In this work, we provide a perspective of the emerging and potential translational applications of 2D materials including semiconductors, semimetals, and insulators that comprise the basic material set for diverse nanosystems. Applications include RF transceivers, smart systems, the so-called internet of things, and neurotechnology. We will review the DC and RF electronic performance of graphene and BP thin film transistors. 2D materials at sub-um channel length have so far enabled cut-off frequencies from baseband to 100GHz suitable for low-power RF and sub-THz concepts.
Anisotropic 2D Materials for Tunable Hyperbolic Plasmonics.
Nemilentsau, Andrei; Low, Tony; Hanson, George
2016-02-12
Motivated by the recent emergence of a new class of anisotropic 2D materials, we examine their electromagnetic modes and demonstrate that a broad class of the materials can host highly directional hyperbolic plasmons. Their propagation direction can be manipulated on the spot by gate doping, enabling hyperbolic beam reflection, refraction, and bending. The realization of these natural 2D hyperbolic media opens up a new avenue in dynamic control of hyperbolic plasmons not possible in the 3D version.
RNA folding pathways and kinetics using 2D energy landscapes.
Senter, Evan; Dotu, Ivan; Clote, Peter
2015-01-01
RNA folding pathways play an important role in various biological processes, such as (i) the hok/sok (host-killing/suppression of killing) system in E. coli to check for sufficient plasmid copy number, (ii) the conformational switch in spliced leader (SL) RNA from Leptomonas collosoma, which controls trans splicing of a portion of the '5 exon, and (iii) riboswitches--portions of the 5' untranslated region of messenger RNA that regulate genes by allostery. Since RNA folding pathways are determined by the energy landscape, we describe a novel algorithm, FFTbor2D, which computes the 2D projection of the energy landscape for a given RNA sequence. Given two metastable secondary structures A, B for a given RNA sequence, FFTbor2D computes the Boltzmann probability p(x, y) = Z(x,y)/Z that a secondary structure has base pair distance x from A and distance y from B. Using polynomial interpolationwith the fast Fourier transform,we compute p(x, y) in O(n(5)) time and O(n(2)) space, which is an improvement over an earlier method, which runs in O(n(7)) time and O(n(4)) space. FFTbor2D has potential applications in synthetic biology, where one might wish to design bistable switches having target metastable structures A, B with favorable pathway kinetics. By inverting the transition probability matrix determined from FFTbor2D output, we show that L. collosoma spliced leader RNA has larger mean first passage time from A to B on the 2D energy landscape, than 97.145% of 20,000 sequences, each having metastable structures A, B. Source code and binaries are freely available for download at http://bioinformatics.bc.edu/clotelab/FFTbor2D. The program FFTbor2D is implemented in C++, with optional OpenMP parallelization primitives.
Supported and Free-Standing 2D Semimetals
2015-01-15
of this effort on focusing on rare- earth arsenides (RE-A), although not a van der Waals 2D solid, nonetheless, exhibits substantial 2D quantum size...this effort on focusing on rare- earth arsenides (RE- A), although not a van der Waals 20 solid, nonetheless, exhibits substantial 20 quantum size...Brongersma and S.R. Bank, "Rare- earth monopnictide alloys for tunable, epitaxial metals" in preparation. iii. S. Rahimi, E. M. Krivoy, J. Lee, M. E
Application of 2-D graphical representation of DNA sequence
NASA Astrophysics Data System (ADS)
Liao, Bo; Tan, Mingshu; Ding, Kequan
2005-10-01
Recently, we proposed a 2-D graphical representation of DNA sequence [Bo Liao, A 2-D graphical representation of DNA sequence, Chem. Phys. Lett. 401 (2005) 196-199]. Based on this representation, we consider properties of mutations and compute the similarities among 11 mitochondrial sequences belonging to different species. The elements of the similarity matrix are used to construct phylogenic tree. Unlike most existing phylogeny construction methods, the proposed method does not require multiple alignment.
phase_space_cosmo_fisher: Fisher matrix 2D contours
NASA Astrophysics Data System (ADS)
Stark, Alejo
2016-11-01
phase_space_cosmo_fisher produces Fisher matrix 2D contours from which the constraints on cosmological parameters can be derived. Given a specified redshift array and cosmological case, 2D marginalized contours of cosmological parameters are generated; the code can also plot the derivatives used in the Fisher matrix. In addition, this package can generate 3D plots of qH^2 and other cosmological quantities as a function of redshift and cosmology.
A simultaneous 2D/3D autostereo workstation
NASA Astrophysics Data System (ADS)
Chau, Dennis; McGinnis, Bradley; Talandis, Jonas; Leigh, Jason; Peterka, Tom; Knoll, Aaron; Sumer, Aslihan; Papka, Michael; Jellinek, Julius
2012-03-01
We present a novel immersive workstation environment that scientists can use for 3D data exploration and as their everyday 2D computer monitor. Our implementation is based on an autostereoscopic dynamic parallax barrier 2D/3D display, interactive input devices, and a software infrastructure that allows client/server software modules to couple the workstation to scientists' visualization applications. This paper describes the hardware construction and calibration, software components, and a demonstration of our system in nanoscale materials science exploration.
Phylogenetic tree construction based on 2D graphical representation
NASA Astrophysics Data System (ADS)
Liao, Bo; Shan, Xinzhou; Zhu, Wen; Li, Renfa
2006-04-01
A new approach based on the two-dimensional (2D) graphical representation of the whole genome sequence [Bo Liao, Chem. Phys. Lett., 401(2005) 196.] is proposed to analyze the phylogenetic relationships of genomes. The evolutionary distances are obtained through measuring the differences among the 2D curves. The fuzzy theory is used to construct phylogenetic tree. The phylogenetic relationships of H5N1 avian influenza virus illustrate the utility of our approach.
Moments of catchment storm area
NASA Technical Reports Server (NTRS)
Eagleson, P. S.; Wang, Q.
1985-01-01
The portion of a catchment covered by a stationary rainstorm is modeled by the common area of two overlapping circles. Given that rain occurs within the catchment and conditioned by fixed storm and catchment sizes, the first two moments of the distribution of the common area are derived from purely geometrical considerations. The variance of the wetted fraction is shown to peak when the catchment size is equal to the size of the predominant storm. The conditioning on storm size is removed by assuming a probability distribution based upon the observed fractal behavior of cloud and rainstorm areas.
Fermion dipole moment and holography
NASA Astrophysics Data System (ADS)
Kulaxizi, Manuela; Rahman, Rakibur
2015-12-01
In the background of a charged AdS black hole, we consider a Dirac particle endowed with an arbitrary magnetic dipole moment. For non-zero charge and dipole coupling of the bulk fermion, we find that the dual boundary theory can be plagued with superluminal modes. Requiring consistency of the dual CFT amounts to constraining the strength of the dipole coupling by an upper bound. We briefly discuss the implications of our results for the physics of holographic non-Fermi liquids.
Regulation of NKG2D ligand gene expression.
Eagle, Robert A; Traherne, James A; Ashiru, Omodele; Wills, Mark R; Trowsdale, John
2006-03-01
The activating immunoreceptor NKG2D has seven known host ligands encoded by the MHC class I chain-related MIC and ULBP/RAET genes. Why there is such diversity of NKG2D ligands is not known but one hypothesis is that they are differentially expressed in different tissues in response to different stresses. To explore this, we compared expression patterns and promoters of NKG2D ligand genes. ULBP/RAET genes were transcribed independent of each other in a panel of cell lines. ULBP/RAET gene expression was upregulated on infection with human cytomegalovirus; however, a clinical strain, Toledo, induced expression more slowly than did a laboratory strain, AD169. ULBP4/RAET1E was not induced by infection with either strain. To investigate the mechanisms behind the similarities and differences in NKG2D ligand gene expression a comparative sequence analysis of NKG2D ligand gene putative promoter regions was conducted. Sequence alignments demonstrated that there was significant sequence diversity; however, one region of high similarity between most of the genes is evident. This region contains a number of potential transcription factor binding sites, including those involved in shock responses and sites for retinoic acid-induced factors. Promoters of some NKG2D ligand genes are polymorphic and several sequence alterations in these alleles abolished putative transcription factor binding.
CYP2D6 variability in populations from Venezuela.
Moreno, Nancy; Flores-Angulo, Carlos; Villegas, Cecilia; Mora, Yuselin
2016-12-01
CYP2D6 is an important cytochrome P450 enzyme that plays an important role in the metabolism of about 25% of currently prescribed drugs. The presence of polymorphisms in the CYP2D6 gene may modulate enzyme level and activity, thereby affecting individual responses to pharmacological treatments. The most prevalent diseases in the admixed population from Venezuela are cardiovascular and cancer, whereas viral, bacterial and parasitic diseases, particularly malaria, are prevalent in Amerindian populations; in the treatment of these diseases, several drugs that are metabolized by CYP2D6 are used. In this work, we reviewed the data on CYP2D6 variability and predicted metabolizer phenotypes, in healthy volunteers of two admixed and five Amerindian populations from Venezuela. The Venezuelan population is very heterogeneous as a result of the genetic admixture of three major ethnical components: Europeans, Africans and Amerindians. There are noticeable inter-regional and inter-population differences in the process of mixing of this population. Hitherto, there are few published studies in Venezuela on CYP2D6; therefore, it is necessary to increase research in this regard, in particular to develop studies with a larger sample size. There is a considerable amount of work remaining before CYP2D6 is integrated into clinical practice in Venezuela.
2D microscopic model of graphene fracture properties
NASA Astrophysics Data System (ADS)
Hess, Peter
2015-05-01
An analytical two-dimensional (2D) microscopic fracture model based on Morse-type interaction is derived containing no adjustable parameter. From the 2D Young’s moduli and 2D intrinsic strengths of graphene measured by nanoindentation based on biaxial tension and calculated by density functional theory for uniaxial tension the widely unknown breaking force, line or edge energy, surface energy, fracture toughness, and strain energy release rate were determined. The simulated line energy agrees well with ab initio calculations and the fracture toughness of perfect graphene sheets is in good agreement with molecular dynamics simulations and the fracture toughness evaluated for defective graphene using the Griffith relation. Similarly, the estimated critical strain energy release rate agrees well with result of various theoretical approaches based on the J-integral and surface energy. The 2D microscopic model, connecting 2D and three-dimensional mechanical properties in a consistent way, provides a versatile relationship to easily access all relevant fracture properties of pristine 2D solids.
Perception and Haptic Rendering of Friction Moments.
Kawasaki, H; Ohtuka, Y; Koide, S; Mouri, T
2011-01-01
This paper considers moments due to friction forces on the human fingertip. A computational technique called the friction moment arc method is presented. The method computes the static and/or dynamic friction moment independent of a friction force calculation. In addition, a new finger holder to display friction moment is presented. This device incorporates a small brushless motor and disk, and connects the human's finger to an interface finger of the five-fingered haptic interface robot HIRO II. Subjects' perception of friction moment while wearing the finger holder, as well as perceptions during object manipulation in a virtual reality environment, were evaluated experimentally.
Predicting Robust Learning with the Visual Form of the Moment-by-Moment Learning Curve
ERIC Educational Resources Information Center
Baker, Ryan S.; Hershkovitz, Arnon; Rossi, Lisa M.; Goldstein, Adam B.; Gowda, Sujith M.
2013-01-01
We present a new method for analyzing a student's learning over time for a specific skill: analysis of the graph of the student's moment-by-moment learning over time. Moment-by-moment learning is calculated using a data-mined model that assesses the probability that a student learned a skill or concept at a specific time during learning (Baker,…
Moment calculations by digital filters
NASA Astrophysics Data System (ADS)
Budrikis, Z. L.; Hatamian, M.
1984-02-01
A simple recursive algorithm is presented for computing moments of two-dimensional integer arrays. It uses only additions, and can be implemented for high speed and real time computation at video rates. The Complementary Metal-Oxide Semiconductor (CMOS), Very Large-Scale Integrated (VLSI) implementation of the algorithm in a single chip that can calculate the 16 moments on a 512 x 512 array of 8-bit integers in real time (at video rate) is described. Such a chip can have potential applications in image processing, graphics, and robotics. The basic building block of the system is a single-pole digital filter that is implemented by recursive addition. The complexities involved in designing the chip, as well as its area, are significantly reduced by taking advantage of the fact that the column samples of the data array can be processed at a much slower rate than the row samples. An estimate of the chip area obtained from the layout design of the individual cells is given.
2D Hexagonal Boron Nitride (2D-hBN) Explored for the Electrochemical Sensing of Dopamine.
Khan, Aamar F; Brownson, Dale A C; Randviir, Edward P; Smith, Graham C; Banks, Craig E
2016-10-04
Crystalline 2D hexagonal boron nitride (2D-hBN) nanosheets are explored as a potential electrocatalyst toward the electroanalytical sensing of dopamine (DA). The 2D-hBN nanosheets are electrically wired via a drop-casting modification process onto a range of commercially available carbon supporting electrodes, including glassy carbon (GC), boron-doped diamond (BDD), and screen-printed graphitic electrodes (SPEs). 2D-hBN has not previously been explored toward the electrochemical detection/electrochemical sensing of DA. We critically evaluate the potential electrocatalytic performance of 2D-hBN modified electrodes, the effect of supporting carbon electrode platforms, and the effect of "mass coverage" (which is commonly neglected in the 2D material literature) toward the detection of DA. The response of 2D-hBN modified electrodes is found to be largely dependent upon the interaction between 2D-hBN and the underlying supporting electrode material. For example, in the case of SPEs, modification with 2D-hBN (324 ng) improves the electrochemical response, decreasing the electrochemical oxidation potential of DA by ∼90 mV compared to an unmodified SPE. Conversely, modification of a GC electrode with 2D-hBN (324 ng) resulted in an increased oxidation potential of DA by ∼80 mV when compared to the unmodified electrode. We explore the underlying mechanisms of the aforementioned examples and infer that electrode surface interactions and roughness factors are critical considerations. 2D-hBN is utilized toward the sensing of DA in the presence of the common interferents ascorbic acid (AA) and uric acid (UA). 2D-hBN is found to be an effective electrocatalyst in the simultaneous detection of DA and UA at both pH 5.0 and 7.4. The peak separations/resolution between DA and UA increases by ∼70 and 50 mV (at pH 5.0 and 7.4, respectively, when utilizing 108 ng of 2D-hBN) compared to unmodified SPEs, with a particularly favorable response evident in pH 5.0, giving rise to a
Tekdaş, Duygu Aydın; Durmuş, Mahmut; Yanık, Hülya; Ahsen, Vefa
2012-07-01
Thiol stabilized CdTe quantum dot (QD) nanoparticles were synthesized in aqueous phase and were used as energy donors to tetra-triethyleneoxythia substituted aluminum, gallium and indium phthalocyanines through fluorescence resonance energy transfer (FRET). Energy transfer occurred from the QDs to phthalocyanines upon photoexcitation of the QDs. An enhancement in efficiency of energy transfer with the nature of the carboxylic thiol stabilizer on the QDs was observed. As a result of the nanoparticle and the phthalocyanine mixing, the photoluminescence efficiency of the phthalocyanine moieties in the mixtures does not strictly follow the quantum yields of the bare phthalocyanines. The photochemistry study of phthalocyanines in the presence of the QDs revealed high singlet oxygen quantum yield, hence the possibility of using QDs in combination with phthalocyanines as photosensitizers in photodynamic therapy of cancer. The fluorescence of the CdTe quantum dots-phthalocyanine conjugates (QDs-Pc) were effectively quenched by addition of 1,4-benzoquinone.
Roton-maxon excitation spectrum for Q2D weakly interacted dipolar excitons
NASA Astrophysics Data System (ADS)
Fedorov, Aleksey; Kurbakov, Igor; Lozovik, Yurii
2014-03-01
Remarkable progress was achieved in investigation of collective properties and BEC of quasiparticles, e.g., excitons and polaritons. As it well known their small effective mass provides sufficiently high BEC temperature. However, in reality excitons lifetime is not enough to achieve thermodynamical equilibrium. Spatial separation of electrons and holes in semiconductor layer suppresses recombination process, and exciton lifetime increases sufficiently. Moreover, the separation results in appearance of excitons dipole moments. We predict generation of roton-maxon excitation spectrum for BEC of dipolar excitons in weak correlation regime in Q2D geometry of semiconductor layer. The effect of roton-maxon spectrum is the result of attraction and anisotropy of dipole-dipole interaction in Q2D geometry, and it can be viewed as residual phenomena of phonon collapse for 3D dipoles. According to our estimation effects of BEC and roton-maxon spectrum are principally observable experimentally for excitons in crossed electromagnetic fields in GaAs heterostructures. The work was supported by the RFBR (14-02-00937, 14-08-00606). A.K.F. is an RQC fellow.
Structural and magnetic properties of DyMn(2)D(6) synthesized under high deuterium pressure.
Paul-Boncour, V; Filipek, S M; Wierzbicki, R; André, G; Bourée, F; Guillot, M
2009-01-07
DyMn(2)D(6) has been prepared by applying high gaseous deuterium pressure on DyMn(2). This phase is isostructural with other RMn(2)D(6) (R = Y, Er) compounds and crystallizes with a K(2)PtCl(6) type structure having an ordered anion and a partially disordered cation arrangement because Dy and half the Mn atoms are randomly substituted in the same 8c site. The reverse susceptibility follows a Curie-Weiss law with an effective moment of 10 μ(B) similar to that of DyMn(2). Short range magnetic order, corresponding to ferromagnetic correlations, is observed in the neutron patterns up to 10 K and can be attributed to Dy-Dy interactions. The decomposition of the deuteride into Mn and DyD(2), studied by thermal gravimetric analysis, occurs between 470 and 650 K. A further deuterium desorption takes place above 920 K.
NASA Astrophysics Data System (ADS)
Fan, Jinping; Lu, Xiaoxu; Liu, Shengde; Zhong, Liyun
2015-10-01
In this study, by using of near-field scanning optical microscopy (NSOM)/immune-labeling quantum dot (QD)-based dual-color imaging system, we achieved the direct visualization of nanoscale profiles for distribution and organization of CD4 and CD25 molecules in T cells. A novel and interesting finding was that though CD25 clustering as nanodomains were observed on the surface of CD4+CD25high regulatory T cells, these CD25 nanodomains were not co-localized with CD4 nanodomains. This result presented that the formation of these CD25 nanodomains on the surface of CD4+CD25high T cells were not associated with the response of T cell receptor (TCR)/CD3-dependent signal transduction. In contrast, on the surface of CD4+CD25low T cells, CD25 molecules distributed randomly without forming nanodomains while CD4 clustering as nanodomains can be observed; on the surface of CD8+CD25+ T cells, CD25 clustering as nanodomains and co-localization with CD8 nanodomains were observed. Collectively, above these results exhibited that TCR/CD3-based microdomains were indeed required for TCR/CD3-mediated T cells activation and enhanced the immune activity of CD4+CD25low T cells or CD8+CD25+ T cells. In particular, it was found that the formation of CD25 nanodomains and their segregation from TCR/CD3 microdomains were the intrinsic capability of CD4+CD25high T cells, suggesting this specific imaging feature of CD25 should be greatly associated with the regulatory activity of CD4+CD25high T cells. Importantly, this novel NSOM/QD-based dual-color imaging system will provide a useful tool for the research of distribution-function relationship of cell-surface molecules.
An interactive 2-D power-line modeling and simulation tool
NASA Astrophysics Data System (ADS)
Hull, David; Adelman, Ross
2012-06-01
The U.S. Army Research Laboratory's Power-Line unmanned aerial vehicle (UAV) Modeling and Simulation (ARL-PLUMS) is a tool for estimating and analyzing quasi-static electric and magnetic fields due to power lines. This tool consists of an interactive 2-D graphical user interface (GUI) and a compute engine that can be used to calculate and visualize the E-Field and H-Field due to as many as seven conductors (two 3-phase circuits and a ground wire). ARL-PLUMS allows the user to set the geometry of the lines and the load conditions on those lines, and then calculate Ey, Ez, Hy, or Hz along a linear path or cutting plane, or in the form of a movie. The path can be along the ground or in the air to simulate the fields that might be observed, for example, by a robotic vehicle or a UAV. ARL-PLUMS makes several simplifying assumptions in order to allow simulations to be completed on a laptop PC interactively. In most cases, the results are excellent, providing a "90% solution" in just a few minutes of total modeling and simulation time. This paper describes the physics used by ARL-PLUMS, including the simplifying assumptions and the 2-D Method of Moments solver. Examples of electric and magnetic fields for different wire configurations, including typical 3-phase distribution and transmissions lines, are provided. Comparisons to similar results using a full 3-D model are also shown, and a discussion of errors that may be expected from the 2-D simulations is provided.
2-D Coda and Direct Wave Attenuation Tomography in Northern Italy
Morasca, P; Mayeda, K; Gok, R; Phillips, W S; Malagnini, L
2007-10-17
A 1-D coda method was proposed by Mayeda et al. (2003) in order to obtain stable seismic source moment-rate spectra using narrowband coda envelope measurements. That study took advantage of the averaging nature of coda waves to derive stable amplitude measurements taking into account all propagation, site, and Sto-coda transfer function effects. Recently this methodology was applied to micro earthquake data sets from three sub-regions of northern Italy (i.e., western Alps, northern Apennines and eastern Alps). Since the study regions were small, ranging between local-to-near-regional distances, the simple 1-D path assumptions used in the coda method worked very well. The lateral complexity of this region would suggest, however, that a 2-D path correction might provide even better results if the datasets were combined, especially when paths traverse larger distances and complicated regions. The structural heterogeneity of northern Italy makes the region ideal to test the extent to which coda variance can be reduced further by using a 2-D Q tomography technique. The approach we use has been developed by Phillips et al. (2005) and is an extension of previous amplitude ratio techniques to remove source effects from the inversion. The method requires some assumptions such as isotropic source radiation which is generally true for coda waves. Our results are compared against direct Swave inversions for 1/Q and results from both share very similar attenuation features that coincide with known geologic structures. We compare our results with those derived from direct waves as well as some recent results from northern California obtained by Mayeda et al. (2005) which tested the same tomographic methodology applied in this study to invert for 1/Q. We find that 2-D coda path corrections for this region significantly improve upon the 1-D corrections, in contrast to California where only a marginal improvement was observed. We attribute this difference to stronger lateral
Regulation of ligands for the activating receptor NKG2D
Mistry, Anita R; O'Callaghan, Chris A
2007-01-01
The outcome of an encounter between a cytotoxic cell and a potential target cell depends on the balance of signals from inhibitory and activating receptors. Natural Killer group 2D (NKG2D) has recently emerged as a major activating receptor on T lymphocytes and natural killer cells. In both humans and mice, multiple different genes encode ligands for NKG2D, and these ligands are non-classical major histocompatibility complex class I molecules. The NKG2D–ligand interaction triggers an activating signal in the cell expressing NKG2D and this promotes cytotoxic lysis of the cell expressing the ligand. Most normal tissues do not express ligands for NKG2D, but ligand expression has been documented in tumour and virus-infected cells, leading to lysis of these cells. Tight regulation of ligand expression is important. If there is inappropriate expression in normal tissues, this will favour autoimmune processes, whilst failure to up-regulate the ligands in pathological conditions would favour cancer development or dissemination of intracellular infection. PMID:17614877
Rotation invariance principles in 2D/3D registration
NASA Astrophysics Data System (ADS)
Birkfellner, Wolfgang; Wirth, Joachim; Burgstaller, Wolfgang; Baumann, Bernard; Staedele, Harald; Hammer, Beat; Gellrich, Niels C.; Jacob, Augustinus L.; Regazzoni, Pietro; Messmer, Peter
2003-05-01
2D/3D patient-to-computed tomography (CT) registration is a method to determine a transformation that maps two coordinate systems by comparing a projection image rendered from CT to a real projection image. Applications include exact patient positioning in radiation therapy, calibration of surgical robots, and pose estimation in computer-aided surgery. One of the problems associated with 2D/3D registration is the fast that finding a registration includes sovling a minimization problem in six degrees-of-freedom in motion. This results in considerable time expenses since for each iteration step at least one volume rendering has to be computed. We show that by choosing an appropriate world coordinate system and by applying a 2D/2D registration method in each iteration step, the number of iterations can be grossly reduced from n6 to n5. Here, n is the number of discrete variations aroudn a given coordinate. Depending on the configuration of the optimization algorithm, this reduces the total number of iterations necessary to at least 1/3 of its original value. The method was implemented and extensively tested on simulated x-ray images of a pelvis. We conclude that this hardware-indepenent optimization of 2D/3D registration is a step towards increasing the acceptance of this promising method for a wide number of clinical applications.
2D nanostructures for water purification: graphene and beyond.
Dervin, Saoirse; Dionysiou, Dionysios D; Pillai, Suresh C
2016-08-18
Owing to their atomically thin structure, large surface area and mechanical strength, 2D nanoporous materials are considered to be suitable alternatives for existing desalination and water purification membrane materials. Recent progress in the development of nanoporous graphene based materials has generated enormous potential for water purification technologies. Progress in the development of nanoporous graphene and graphene oxide (GO) membranes, the mechanism of graphene molecular sieve action, structural design, hydrophilic nature, mechanical strength and antifouling properties and the principal challenges associated with nanopore generation are discussed in detail. Subsequently, the recent applications and performance of newly developed 2D materials such as 2D boron nitride (BN) nanosheets, graphyne, molybdenum disulfide (MoS2), tungsten chalcogenides (WS2) and titanium carbide (Ti3C2Tx) are highlighted. In addition, the challenges affecting 2D nanostructures for water purification are highlighted and their applications in the water purification industry are discussed. Though only a few 2D materials have been explored so far for water treatment applications, this emerging field of research is set to attract a great deal of attention in the near future.
2D Materials for Optical Modulation: Challenges and Opportunities.
Yu, Shaoliang; Wu, Xiaoqin; Wang, Yipei; Guo, Xin; Tong, Limin
2017-02-21
Owing to their atomic layer thickness, strong light-material interaction, high nonlinearity, broadband optical response, fast relaxation, controllable optoelectronic properties, and high compatibility with other photonic structures, 2D materials, including graphene, transition metal dichalcogenides and black phosphorus, have been attracting increasing attention for photonic applications. By tuning the carrier density via electrical or optical means that modifies their physical properties (e.g., Fermi level or nonlinear absorption), optical response of the 2D materials can be instantly changed, making them versatile nanostructures for optical modulation. Here, up-to-date 2D material-based optical modulation in three categories is reviewed: free-space, fiber-based, and on-chip configurations. By analysing cons and pros of different modulation approaches from material and mechanism aspects, the challenges faced by using these materials for device applications are presented. In addition, thermal effects (e.g., laser induced damage) in 2D materials, which are critical to practical applications, are also discussed. Finally, the outlook for future opportunities of these 2D materials for optical modulation is given.
2D DIGE saturation labeling for minute sample amounts.
Arnold, Georg J; Fröhlich, Thomas
2012-01-01
The 2D DIGE technique, based on fluorophores covalently linked to amino acid side chain residues and the concept of an internal standard, has significantly improved reproducibility, sensitivity, and the dynamic range of protein quantification. In saturation DIGE, sulfhydryl groups of cysteines are labeled with cyanine dyes to completion, providing a so far unraveled sensitivity for protein detection and quantification in 2D gel-based proteomic experiments. Only a few micrograms of protein per 2D gel facilitate the analysis of about 2,000 analytes from complex mammalian cell or tissue samples. As a consequence, 2D saturation DIGE is the method of choice when only minute sample amounts are available for quantitative proteome analysis at the level of proteins rather than peptides. Since very low amounts of samples have to be handled in a reproducible manner, saturation DIGE-based proteomic experiments are technically demanding. Moreover, successful saturation DIGE approaches require a strict adherence to adequate reaction conditions at each step. This chapter is dedicated to colleagues already experienced in 2D PAGE protein separation and intends to support the establishment of this ultrasensitive technique in proteomic workgroups. We provide basic guidelines for the experimental design and discuss crucial aspects concerning labeling chemistry, sample preparation, and pitfalls caused by labeling artifacts. A detailed step-by-step protocol comprises all aspects from initial sample preparation to image analysis and statistical evaluation. Furthermore, we describe the generation of preparative saturation DIGE gels necessary for mass spectrometry-based spot identification.
Mermin–Wagner fluctuations in 2D amorphous solids
Illing, Bernd; Fritschi, Sebastian; Kaiser, Herbert; Klix, Christian L.; Maret, Georg; Keim, Peter
2017-01-01
In a recent commentary, J. M. Kosterlitz described how D. Thouless and he got motivated to investigate melting and suprafluidity in two dimensions [Kosterlitz JM (2016) J Phys Condens Matter 28:481001]. It was due to the lack of broken translational symmetry in two dimensions—doubting the existence of 2D crystals—and the first computer simulations foretelling 2D crystals (at least in tiny systems). The lack of broken symmetries proposed by D. Mermin and H. Wagner is caused by long wavelength density fluctuations. Those fluctuations do not only have structural impact, but additionally a dynamical one: They cause the Lindemann criterion to fail in 2D in the sense that the mean squared displacement of atoms is not limited. Comparing experimental data from 3D and 2D amorphous solids with 2D crystals, we disentangle Mermin–Wagner fluctuations from glassy structural relaxations. Furthermore, we demonstrate with computer simulations the logarithmic increase of displacements with system size: Periodicity is not a requirement for Mermin–Wagner fluctuations, which conserve the homogeneity of space on long scales. PMID:28137872
Sparse radar imaging using 2D compressed sensing
NASA Astrophysics Data System (ADS)
Hou, Qingkai; Liu, Yang; Chen, Zengping; Su, Shaoying
2014-10-01
Radar imaging is an ill-posed linear inverse problem and compressed sensing (CS) has been proved to have tremendous potential in this field. This paper surveys the theory of radar imaging and a conclusion is drawn that the processing of ISAR imaging can be denoted mathematically as a problem of 2D sparse decomposition. Based on CS, we propose a novel measuring strategy for ISAR imaging radar and utilize random sub-sampling in both range and azimuth dimensions, which will reduce the amount of sampling data tremendously. In order to handle 2D reconstructing problem, the ordinary solution is converting the 2D problem into 1D by Kronecker product, which will increase the size of dictionary and computational cost sharply. In this paper, we introduce the 2D-SL0 algorithm into the reconstruction of imaging. It is proved that 2D-SL0 can achieve equivalent result as other 1D reconstructing methods, but the computational complexity and memory usage is reduced significantly. Moreover, we will state the results of simulating experiments and prove the effectiveness and feasibility of our method.
Mean flow and anisotropic cascades in decaying 2D turbulence
NASA Astrophysics Data System (ADS)
Liu, Chien-Chia; Cerbus, Rory; Gioia, Gustavo; Chakraborty, Pinaki
2015-11-01
Many large-scale atmospheric and oceanic flows are decaying 2D turbulent flows embedded in a non-uniform mean flow. Despite its importance for large-scale weather systems, the affect of non-uniform mean flows on decaying 2D turbulence remains unknown. In the absence of mean flow it is well known that decaying 2D turbulent flows exhibit the enstrophy cascade. More generally, for any 2D turbulent flow, all computational, experimental and field data amassed to date indicate that the spectrum of longitudinal and transverse velocity fluctuations correspond to the same cascade, signifying isotropy of cascades. Here we report experiments on decaying 2D turbulence in soap films with a non-uniform mean flow. We find that the flow transitions from the usual isotropic enstrophy cascade to a series of unusual and, to our knowledge, never before observed or predicted, anisotropic cascades where the longitudinal and transverse spectra are mutually independent. We discuss implications of our results for decaying geophysical turbulence.
2-D Clinostat for Simulated Microgravity Experiments with Arabidopsis Seedlings
NASA Astrophysics Data System (ADS)
Wang, Hui; Li, Xugang; Krause, Lars; Görög, Mark; Schüler, Oliver; Hauslage, Jens; Hemmersbach, Ruth; Kircher, Stefan; Lasok, Hanna; Haser, Thomas; Rapp, Katja; Schmidt, Jürgen; Yu, Xin; Pasternak, Taras; Aubry-Hivet, Dorothée; Tietz, Olaf; Dovzhenko, Alexander; Palme, Klaus; Ditengou, Franck Anicet
2016-04-01
Ground-based simulators of microgravity such as fast rotating 2-D clinostats are valuable tools to study gravity related processes. We describe here a versatile g-value-adjustable 2-D clinostat that is suitable for plant analysis. To avoid seedling adaptation to 1 g after clinorotation, we designed chambers that allow rapid fixation. A detailed protocol for fixation, RNA isolation and the analysis of selected genes is described. Using this clinostat we show that mRNA levels of LONG HYPOCOTYL 5 (HY5), MIZU-KUSSEI 1 (MIZ1) and microRNA MIR163 are down-regulated in 5-day-old Arabidopsis thaliana roots after 3 min and 6 min of clinorotation using a maximal reduced g-force of 0.02 g, hence demonstrating that this 2-D clinostat enables the characterization of early transcriptomic events during root response to microgravity. We further show that this 2-D clinostat is able to compensate the action of gravitational force as both gravitropic-dependent statolith sedimentation and subsequent auxin redistribution (monitoring D R5 r e v :: G F P reporter) are abolished when plants are clinorotated. Our results demonstrate that 2-D clinostats equipped with interchangeable growth chambers and tunable rotation velocity are suitable for studying how plants perceive and respond to simulated microgravity.
Harmonic moment dynamics in Laplacian growth.
Leshchiner, Alexander; Thrasher, Matthew; Mineev-Weinstein, Mark B; Swinney, Harry L
2010-01-01
Harmonic moments are integrals of integer powers of z=x+iy over a domain. Here, the domain is an exterior of a bubble of air growing in an oil layer between two horizontal closely spaced plates. Harmonic moments are a natural basis for such Laplacian growth phenomena because, unlike other representations, these moments linearize the zero surface tension problem [S. Richardson, J. Fluid Mech. 56, 609 (1972)], so that all moments except the lowest one (the area of the bubble) are conserved in time. In our experiments, we directly determine the harmonic moments and show that for nonzero surface tension, all moments (except the lowest one) decay in time rather than exhibiting the divergences of other representations. Further, we derive an expression that relates the derivative of the k(th) harmonic moment M(k) to measurable quantities (surface tension, viscosity, the distance between the plates, and a line integral over the contour encompassing the growing bubble). The laboratory observations are in good accord with the expression we derive for dM(k)/dt , which is proportional to the surface tension; thus in the zero surface tension limit, the moments (above k=0) are all conserved, in accord with Richardson's theory. In addition, from the measurements of the time evolution of the harmonic moments we obtain a value for the surface tension that is within 20% of the accepted value. In conclusion, our analysis and laboratory observations demonstrate that an interface dynamics description in terms of harmonic moments is physically realizable and robust.
The classical model for moment tensors
NASA Astrophysics Data System (ADS)
Tape, W.; Tape, C.
2013-12-01
A seismic moment tensor is a description of an earthquake source, but the description is indirect. The moment tensor describes seismic radiation rather than the actual physical process that initiates the radiation. A moment tensor 'model' then ties the physical process to the moment tensor. The model is not unique, and the physical process is therefore not unique. In the classical moment tensor model (Aki and Richards, 1980), an earthquake arises from slip along a planar fault, but with the slip not necessarily in the plane of the fault. The model specifies the resulting moment tensor in terms of the slip vector, the fault normal vector, and the Lame elastic parameters, assuming isotropy. We review the classical model in the context of the fundamental lune. The lune is closely related to the space of moment tensors, and it provides a setting that is conceptually natural as well as pictorial. In addition to the classical model, we consider a crack plus double couple model (CDC model) in which a moment tensor is regarded as the sum of a crack tensor and a double couple. A compilation of full moment tensors from the literature reveals large deviations in Poisson's ratio as implied by the classical model. Either the classical model is inadequate or the published full moment tensors have very large uncertainties. We question the common interpretation of the isotropic component as a volume change in the source region.
Kraloua, B.; Hennad, A.
2008-09-23
The aim of this paper is to determine electric and physical properties by 2D modelling of glow discharge low pressure in continuous regime maintained by term constant source. This electric discharge is confined in reactor plan-parallel geometry. This reactor is filled by Argon monatomic gas. Our continuum model the order two is composed the first three moments the Boltzmann's equations coupled with Poisson's equation by self consistent method. These transport equations are discretized by the finite volumes method. The equations system is resolved by a new technique, it is about the N-BEE explicit scheme using the time splitting method.
Leblanc, M D; Whitehead, J P; Plumer, M L
2013-05-15
A combination of Metropolis and modified Wolff cluster algorithms is used to examine the impact of uniaxial single-ion anisotropy on the phase transition to ferromagnetic order of Heisenberg macrospins on a 2D square lattice. This forms the basis of a model for granular perpendicular recording media where macrospins represent the magnetic moment of grains. The focus of this work is on the interplay between anisotropy D, intragrain exchange J' and intergrain exchange J on the ordering temperature T(C) and extends our previous reported analysis of the granular Ising model. The role of intragrain degrees of freedom in heat assisted magnetic recording is discussed.
NASA Astrophysics Data System (ADS)
Leblanc, M. D.; Whitehead, J. P.; Plumer, M. L.
2013-05-01
A combination of Metropolis and modified Wolff cluster algorithms is used to examine the impact of uniaxial single-ion anisotropy on the phase transition to ferromagnetic order of Heisenberg macrospins on a 2D square lattice. This forms the basis of a model for granular perpendicular recording media where macrospins represent the magnetic moment of grains. The focus of this work is on the interplay between anisotropy D, intragrain exchange J‧ and intergrain exchange J on the ordering temperature TC and extends our previous reported analysis of the granular Ising model. The role of intragrain degrees of freedom in heat assisted magnetic recording is discussed.
Magnetic Moments of Excited Baryons
NASA Astrophysics Data System (ADS)
Metag, Volker
2017-01-01
In project A.3, the reaction γ p → π0γ'p has been studied using the TAPS photon spectrometer in the energy range √s= 1221-1331 MeV. Energy tagged photon beams have been produced with the Glasgow tagging spectrometer from electron beams provided by the MAMI-B accelerator. Angle and energy differential cross sections have been measured and compared to theoretical calculations. This comparison allows the magnetic moment of the Δ+ isobar to be extracted for the first time to μΔ+ = [2.7+1.3-1.0(stat)±1.5(syst)±3(theo)] μN. In an extension of the A3 project to the meson sector, the time-like transition form factor of the η meson has been measured with the Crystal Ball/TAPS detector system at MAMI-C.
Hallowell, E M
1999-01-01
In the last decade or so, technological changes--mainly voice mail and e-mail--have made a lot of face-to-face interaction unnecessary. Face-to-face contact has also fallen victim to "virtuality"--many people work at home or are otherwise off-site. Indeed, most people today can't imagine life without such technology and the freedom it grants. But Edward Hallowell, a noted psychiatrist who has been treating patients with anxiety disorders--many of them business executives--for more than 20 years, warns that we are in danger of losing what he calls the human moment: an authentic psychological encounter that can happen only when two people share the same physical space. And, he believes, we may be about to discover the destructive power of its absence. The author relates stories of business-people who have dealt firsthand with the misunderstandings caused by an overreliance on technology. An e-mail message is misconstrued. Someone forwards a voice-mail message to the wrong people. A person takes offense because he was not included on a certain circulation list. Was it an accident? Often the consequences of such misunderstandings, taken individually, are minor. Over time, however, they take a larger toll--both on individuals and on the organizations they work for. The problem, however, is not insoluble. The author cites examples of people who have worked successfully to restore face-to-face contact in their organizations. The bottom line is that the strategic use of the human moment adds color to our lives and helps us build confidence and trust at work. We ignore it at our peril.
Secretory pathways generating immunosuppressive NKG2D ligands
Baragaño Raneros, Aroa; Suarez-Álvarez, Beatriz; López-Larrea, Carlos
2014-01-01
Natural Killer Group 2 member D (NKG2D) activating receptor, present on the surface of various immune cells, plays an important role in activating the anticancer immune response by their interaction with stress-inducible NKG2D ligands (NKG2DL) on transformed cells. However, cancer cells have developed numerous mechanisms to evade the immune system via the downregulation of NKG2DL from the cell surface, including the release of NKG2DL from the cell surface in a soluble form. Here, we review the mechanisms involved in the production of soluble NKG2DL (sNKG2DL) and the potential therapeutic strategies aiming to block the release of these immunosuppressive ligands. Therapeutically enabling the NKG2D-NKG2DL interaction would promote immunorecognition of malignant cells, thus abrogating disease progression. PMID:25050215
Splashing transients of 2D plasmons launched by swift electrons
Lin, Xiao; Kaminer, Ido; Shi, Xihang; Gao, Fei; Yang, Zhaoju; Gao, Zhen; Buljan, Hrvoje; Joannopoulos, John D.; Soljačić, Marin; Chen, Hongsheng; Zhang, Baile
2017-01-01
Launching of plasmons by swift electrons has long been used in electron energy–loss spectroscopy (EELS) to investigate the plasmonic properties of ultrathin, or two-dimensional (2D), electron systems. However, the question of how a swift electron generates plasmons in space and time has never been answered. We address this issue by calculating and demonstrating the spatial-temporal dynamics of 2D plasmon generation in graphene. We predict a jet-like rise of excessive charge concentration that delays the generation of 2D plasmons in EELS, exhibiting an analog to the hydrodynamic Rayleigh jet in a splashing phenomenon before the launching of ripples. The photon radiation, analogous to the splashing sound, accompanies the plasmon emission and can be understood as being shaken off by the Rayleigh jet–like charge concentration. Considering this newly revealed process, we argue that previous estimates on the yields of graphene plasmons in EELS need to be reevaluated. PMID:28138546
Available information in 2D motional Stark effect imaging.
Creese, Mathew; Howard, John
2010-10-01
Recent advances in imaging techniques have allowed the extension of the standard polarimetric 1D motional Stark effect (MSE) diagnostic to 2D imaging of the internal magnetic field of fusion devices [J. Howard, Plasma Phys. Controlled Fusion 50, 125003 (2008)]. This development is met with the challenge of identifying and extracting the new information, which can then be used to increase the accuracy of plasma equilibrium and current density profile determinations. This paper develops a 2D analysis of the projected MSE polarization orientation and Doppler phase shift. It is found that, for a standard viewing position, the 2D MSE imaging system captures sufficient information to allow imaging of the internal vertical magnetic field component B(Z)(r,z) in a tokamak.
Perception-based reversible watermarking for 2D vector maps
NASA Astrophysics Data System (ADS)
Men, Chaoguang; Cao, Liujuan; Li, Xiang
2010-07-01
This paper presents an effective and reversible watermarking approach for digital copyright protection of 2D-vector maps. To ensure that the embedded watermark is insensitive for human perception, we only select the noise non-sensitive regions for watermark embedding by estimating vertex density within each polyline. To ensure the exact recovery of original 2D-vector map after watermark extraction, we introduce a new reversible watermarking scheme based on reversible high-frequency wavelet coefficients modification. Within the former-selected non-sensitive regions, our watermarking operates on the lower-order vertex coordinate decimals with integer wavelet transform. Such operation further reduces the visual distortion caused by watermark embedding. We have validated the effectiveness of our scheme on our real-world city river/building 2D-vector maps. We give extensive experimental comparisons with state-of-the-art methods, including embedding capability, invisibility, and robustness over watermark attacking.
Microscale 2D separation systems for proteomic analysis
Xu, Xin; Liu, Ke; Fan, Z. Hugh
2012-01-01
Microscale 2D separation systems have been implemented in capillaries and microfabricated channels. They offer advantages of faster analysis, higher separation efficiency and less sample consumption than the conventional methods, such as liquid chromatography (LC) in a column and slab gel electrophoresis. In this article, we review their recent advancement, focusing on three types of platforms, including 2D capillary electrophoresis (CE), CE coupling with capillary LC, and microfluidic devices. A variety of CE and LC modes have been employed to construct 2D separation systems via sophistically designed interfaces. Coupling of different separation modes has also been realized in a number of microfluidic devices. These separation systems have been applied for the proteomic analysis of various biological samples, ranging from a single cell to tumor tissues. PMID:22462786
2D materials for photon conversion and nanophotonics
NASA Astrophysics Data System (ADS)
Tahersima, Mohammad H.; Sorger, Volker J.
2015-09-01
The field of two-dimensional (2D) materials has the potential to enable unique applications across a wide range of the electromagnetic spectrum. While 2D-layered materials hold promise for next-generation photon-conversion intrinsic limitations and challenges exist that shall be overcome. Here we discuss the intrinsic limitations as well as application opportunities of this new class of materials, and is sponsored by the NSF program Designing Materials to Revolutionize and Engineer our Future (DMREF) program, which links to the President's Materials Genome Initiative. We present general material-related details for photon conversion, and show that taking advantage of the mechanical flexibility of 2D materials by rolling MoS2/graphene/hexagonal boron nitride stack to a spiral solar cell allows for solar absorption up to 90%.
Rapid-scan coherent 2D fluorescence spectroscopy.
Draeger, Simon; Roeding, Sebastian; Brixner, Tobias
2017-02-20
We developed pulse-shaper-assisted coherent two-dimensional (2D) electronic spectroscopy in liquids using fluorescence detection. A customized pulse shaper facilitates shot-to-shot modulation at 1 kHz and is employed for rapid scanning over all time delays. A full 2D spectrum with 15 × 15 pixels is obtained in approximately 6 s of measurement time (plus further averaging if needed). Coherent information is extracted from the incoherent fluorescence signal via 27-step phase cycling. We exemplify the technique on cresyl violet in ethanol and recover literature-known oscillations as a function of population time. Signal-to-noise behavior is analyzed as a function of the amount of averaging. Rapid scanning provides a 2D spectrum with a root-mean-square error of < 0.05 after 1 min of measurement time.
2D-3D transition of gold cluster anions resolved
NASA Astrophysics Data System (ADS)
Johansson, Mikael P.; Lechtken, Anne; Schooss, Detlef; Kappes, Manfred M.; Furche, Filipp
2008-05-01
Small gold cluster anions Aun- are known for their unusual two-dimensional (2D) structures, giving rise to properties very different from those of bulk gold. Previous experiments and calculations disagree about the number of gold atoms nc where the transition to 3D structures occurs. We combine trapped ion electron diffraction and state of the art electronic structure calculations to resolve this puzzle and establish nc=12 . It is shown that theoretical studies using traditional generalized gradient functionals are heavily biased towards 2D structures. For a correct prediction of the 2D-3D crossover point it is crucial to use density functionals yielding accurate jellium surface energies, such as the Tao-Perdew-Staroverov-Scuseria (TPSS) functional or the Perdew-Burke-Ernzerhof functional modified for solids (PBEsol). Further, spin-orbit effects have to be included, and large, flexible basis sets employed. This combined theoretical-experimental approach is promising for larger gold and other metal clusters.
IUPAP Award: Ion transport in 2D materials
NASA Astrophysics Data System (ADS)
Bao, Wenzhong
Intercalation in 2D materials drastically influences both physical and chemical properties, which leads to a new degree of freedom for fundamental studies and expands the potential applications of 2D materials. In this talk, I will discuss our work in the past two years related to ion intercalation of 2D materials, including insertion of Li and Na ions in graphene and MoS2. We focused on both fundamental mechanism and potential application, e.g. we measured in-situ optical transmittance spectra and electrical transport properties of few-layer graphene (FLG) nanostructures upon electrochemical lithiation/delithiation. By observing a simultaneous increase of both optical transmittance and DC conductivity, strikingly different from other materials, we proposed its application as a next generation transparent electrode.
2d-retrieval For Mipas-envisat
NASA Astrophysics Data System (ADS)
Steck, T.; von Clarmann, T.; Grabowski, U.; Höpfner, M.
Limb sounding of the Earth's atmosphere provides vertically high resolved profiles of geophysical parameters. The long ray path through the atmosphere makes limb sounders sensitive to even little abundant species. On the other hand, horizontal in- homogeneities, if not taken into account properly, can cause systematic errors within the retrieval process. Especially for limb emission measurements in the mid IR, at- mopheric temperature gradients result in considerable vmr retrieval errors if they are neglected. We present a dedicated method of taking full 2D fields of state parameters (indepen- dent of tangent points) into account in the forward model and in the retrieval. The basic idea is that the 2D state vector is updated sequentially for each limb scan. This method is applied to the 2D retrieval of temperature and vmr for simulated radiances as expected from MIPAS-ENVISAT.
Genetics, genomics, and evolutionary biology of NKG2D ligands.
Carapito, Raphael; Bahram, Seiamak
2015-09-01
Human and mouse NKG2D ligands (NKG2DLs) are absent or only poorly expressed by most normal cells but are upregulated by cell stress, hence, alerting the immune system in case of malignancy or infection. Although these ligands are numerous and highly variable (at genetic, genomic, structural, and biochemical levels), they all belong to the major histocompatibility complex class I gene superfamily and bind to a single, invariant, receptor: NKG2D. NKG2D (CD314) is an activating receptor expressed on NK cells and subsets of T cells that have a key role in the recognition and lysis of infected and tumor cells. Here, we review the molecular diversity of NKG2DLs, discuss the increasing appreciation of their roles in a variety of medical conditions, and propose several explanations for the evolutionary force(s) that seem to drive the multiplicity and diversity of NKG2DLs while maintaining their interaction with a single invariant receptor.
Graphene based 2D-materials for supercapacitors
NASA Astrophysics Data System (ADS)
Palaniselvam, Thangavelu; Baek, Jong-Beom
2015-09-01
Ever-increasing energy demands and the depletion of fossil fuels are compelling humanity toward the development of suitable electrochemical energy conversion and storage devices to attain a more sustainable society with adequate renewable energy and zero environmental pollution. In this regard, supercapacitors are being contemplated as potential energy storage devices to afford cleaner, environmentally friendly energy. Recently, a great deal of attention has been paid to two-dimensional (2D) nanomaterials, including 2D graphene and its inorganic analogues (transition metal double layer hydroxides, chalcogenides, etc), as potential electrodes for the development of supercapacitors with high electrochemical performance. This review provides an overview of the recent progress in using these graphene-based 2D materials as potential electrodes for supercapacitors. In addition, future research trends including notable challenges and opportunities are also discussed.
Chemical vapour deposition: Transition metal carbides go 2D
Gogotsi, Yury
2015-08-17
Here, the research community has been steadily expanding the family of few-atom-thick crystals beyond graphene, discovering new materials or producing known materials in a 2D state and demonstrating their unique properties1, 2. Recently, nanometre-thin 2D transition metal carbides have also joined this family3. Writing in Nature Materials, Chuan Xu and colleagues now report a significant advance in the field, showing the synthesis of large-area, high-quality, nanometre-thin crystals of molybdenum carbide that demonstrate low-temperature 2D superconductivity4. Moreover, they also show that other ultrathin carbide crystals, such as tungsten and tantalum carbides, can be grown by chemical vapour deposition with a highmore » crystallinity and very low defect concentration.« less
Optoelectronics based on 2D TMDs and heterostructures
NASA Astrophysics Data System (ADS)
Huo, Nengjie; Yang, Yujue; Li, Jingbo
2017-03-01
2D materials including graphene and TMDs have proven interesting physical properties and promising optoelectronic applications. We reviewed the growth, characterization and optoelectronics based on 2D TMDs and their heterostructures, and demonstrated their unique and high quality of performances. For example, we observed the large mobility, fast response and high photo-responsivity in MoS2, WS2 and WSe2 phototransistors, as well as the novel performances in vdW heterostructures such as the strong interlayer coupling, am-bipolar and rectifying behaviour, and the obvious photovoltaic effect. It is being possible that 2D family materials could play an increasingly important role in the future nano- and opto-electronics, more even than traditional semiconductors such as silicon.
Applications of Doppler Tomography in 2D and 3D
NASA Astrophysics Data System (ADS)
Richards, M.; Budaj, J.; Agafonov, M.; Sharova, O.
2010-12-01
Over the past few years, the applications of Doppler tomography have been extended beyond the usual calculation of 2D velocity images of circumstellar gas flows. This technique has now been used with the new Shellspec spectrum synthesis code to demonstrate the effective modeling of the accretion disk and gas stream in the TT Hya Algol binary. The 2D tomography procedure projects all sources of emission onto a single central (Vx, Vy) velocity plane even though the gas is expected to flow beyond that plane. So, new 3D velocity images were derived with the Radioastronomical Approach method by assuming a grid of Vz values transverse to the central 2D plane. The 3D approach has been applied to the U CrB and RS Vul Algol-type binaries to reveal substantial flow structures beyond the central velocity plane.
Chemical vapour deposition: Transition metal carbides go 2D
Gogotsi, Yury
2015-08-17
Here, the research community has been steadily expanding the family of few-atom-thick crystals beyond graphene, discovering new materials or producing known materials in a 2D state and demonstrating their unique properties^{1, 2}. Recently, nanometre-thin 2D transition metal carbides have also joined this family^{3}. Writing in Nature Materials, Chuan Xu and colleagues now report a significant advance in the field, showing the synthesis of large-area, high-quality, nanometre-thin crystals of molybdenum carbide that demonstrate low-temperature 2D superconductivity^{4}. Moreover, they also show that other ultrathin carbide crystals, such as tungsten and tantalum carbides, can be grown by chemical vapour deposition with a high crystallinity and very low defect concentration.
Real-time 2-D temperature imaging using ultrasound.
Liu, Dalong; Ebbini, Emad S
2010-01-01
We have previously introduced methods for noninvasive estimation of temperature change using diagnostic ultrasound. The basic principle was validated both in vitro and in vivo by several groups worldwide. Some limitations remain, however, that have prevented these methods from being adopted in monitoring and guidance of minimally invasive thermal therapies, e.g., RF ablation and high-intensity-focused ultrasound (HIFU). In this letter, we present first results from a real-time system for 2-D imaging of temperature change using pulse-echo ultrasound. The front end of the system is a commercially available scanner equipped with a research interface, which allows the control of imaging sequence and access to the RF data in real time. A high-frame-rate 2-D RF acquisition mode, M2D, is used to capture the transients of tissue motion/deformations in response to pulsed HIFU. The M2D RF data is streamlined to the back end of the system, where a 2-D temperature imaging algorithm based on speckle tracking is implemented on a graphics processing unit. The real-time images of temperature change are computed on the same spatial and temporal grid of the M2D RF data, i.e., no decimation. Verification of the algorithm was performed by monitoring localized HIFU-induced heating of a tissue-mimicking elastography phantom. These results clearly demonstrate the repeatability and sensitivity of the algorithm. Furthermore, we present in vitro results demonstrating the possible use of this algorithm for imaging changes in tissue parameters due to HIFU-induced lesions. These results clearly demonstrate the value of the real-time data streaming and processing in monitoring, and guidance of minimally invasive thermotherapy.
Towards functional assembly of 3D and 2D nanomaterials
NASA Astrophysics Data System (ADS)
Jacobs, Christopher B.; Wang, Kai; Ievlev, Anton V.; Muckley, Eric S.; Ivanov, Ilia N.
2016-09-01
Functional assemblies of materials can be realized by tuning the work function and band gap of nanomaterials by rational material selection and design. Here we demonstrate the structural assembly of 2D and 3D nanomaterials and show that layering a 2D material monolayer on a 3D metal oxide leads to substantial alteration of both the surface potential and optical properties of the 3D material. A 40 nm thick film of polycrystalline NiO was produced by room temperature rf-sputtering, resulting in a 3D nanoparticle assembly. Chemical vapor deposition (CVD) grown 10-30 μm WS2 flakes (2D material) were placed on the NiO surface using a PDMS stamp transfer technique. The 2D/3D WS2/NiO assembly was characterized using confocal micro Raman spectroscopy to evaluate the vibrational properties and using Kelvin probe force microscopy (KPFM) to evaluate the surface potential. Raman maps of the 2D/3D assembly show spatial non-uniformity of the A1g mode ( 418 cm-1) and the disorder-enhanced longitudinal acoustic mode, 2LA(M) ( 350 cm-1), suggesting that the WS2 exists in a strained condition on when transferred onto 3D polycrystalline NiO. KPFM measurements show that single layer WS2 on SiO2 has a surface potential 75 mV lower than that of SiO2, whereas the surface potential of WS2 on NiO is 15 mV higher than NiO, indicating that WS2 could act as electron donor or acceptor depending on the 3D material it is interfaced with. Thus 2D and 3D materials can be organized into functional assemblies with electron flow controlled by the WS2 either as the electron donor or acceptor.
Laboratory Experiments On Continually Forced 2d Turbulence
NASA Astrophysics Data System (ADS)
Wells, M. G.; Clercx, H. J. H.; Van Heijst, G. J. F.
There has been much recent interest in the advection of tracers by 2D turbulence in geophysical flows. While there is a large body of literature on decaying 2D turbulence or forced 2D turbulence in unbounded domains, there have been very few studies of forced turbulence in bounded domains. In this study we present new experimental results from a continuously forced quasi 2D turbulent field. The experiments are performed in a square Perspex tank filled with water. The flow is made quasi 2D by a steady background rotation. The rotation rate of the tank has a small (<8 %) sinusoidal perturbation which leads to the periodic formation of eddies in the corners of the tank. When the oscillation period of the perturbation is greater than an eddy roll-up time-scale, dipole structures are observed to form. The dipoles can migrate away from the walls, and the interior of the tank is continually filled with vortexs. From experimental visualizations the length scale of the vortexs appears to be largely controlled by the initial formation mechanism and large scale structures are not observed to form at large times. Thus the experiments provide a simple way of cre- ating a continuously forced 2D turbulent field. The resulting structures are in contrast with most previous laboratory experiments on 2D turbulence which have investigated decaying turbulence and have observed the formations of large scale structure. In these experiments, decaying turbulence had been produced by a variety of methods such as the decaying turbulence in the wake of a comb of rods (Massen et al 1999), organiza- tion of vortices in thin conducting liquids (Cardoso et al 1994) or in rotating systems where there are sudden changes in angular rotation rate (Konijnenberg et al 1998). Results of dye visualizations, particle tracking experiments and a direct numerical simulation will be presented and discussed in terms of their oceanographic application. Bibliography Cardoso,O. Marteau, D. &Tabeling, P
2dF grows up: Echidna for the AAT
NASA Astrophysics Data System (ADS)
McGrath, Andrew; Barden, Sam; Miziarski, Stan; Rambold, William; Smith, Greg
2008-07-01
We present the concept design of a new fibre positioner and spectrograph system for the Anglo-Australian Telescope, as a proposed enhancement to the Anglo-Australian Observatory's well-known 2dF facility. A four-fold multiplex enhancement is accomplished by replacing the 400-fibre 2dF fibre positioning robot with a 1600-fibre Echidna unit, feeding three clones of the AAOmega optical spectrograph. Such a facility has the capability of a redshift 1 survey of a large fraction of the southern sky, collecting five to ten thousand spectra per night for a million-galaxy survey.
Noninvasive deep Raman detection with 2D correlation analysis
NASA Astrophysics Data System (ADS)
Kim, Hyung Min; Park, Hyo Sun; Cho, Youngho; Jin, Seung Min; Lee, Kang Taek; Jung, Young Mee; Suh, Yung Doug
2014-07-01
The detection of poisonous chemicals enclosed in daily necessaries is prerequisite essential for homeland security with the increasing threat of terrorism. For the detection of toxic chemicals, we combined a sensitive deep Raman spectroscopic method with 2D correlation analysis. We obtained the Raman spectra from concealed chemicals employing spatially offset Raman spectroscopy in which incident line-shaped light experiences multiple scatterings before being delivered to inner component and yielding deep Raman signal. Furthermore, we restored the pure Raman spectrum of each component using 2D correlation spectroscopic analysis with chemical inspection. Using this method, we could elucidate subsurface component under thick powder and packed contents in a bottle.
Evaluation of 2D ceramic matrix composites in aeroconvective environments
NASA Technical Reports Server (NTRS)
Riccitiello, Salvatore R.; Love, Wendell L.; Balter-Peterson, Aliza
1992-01-01
An evaluation is conducted of a novel ceramic-matrix composite (CMC) material system for use in the aeroconvective-heating environments encountered by the nose caps and wing leading edges of such aerospace vehicles as the Space Shuttle, during orbit-insertion and reentry from LEO. These CMCs are composed of an SiC matrix that is reinforced with Nicalon, Nextel, or carbon refractory fibers in a 2D architecture. The test program conducted for the 2D CMCs gave attention to their subsurface oxidation.
Radiative heat transfer in 2D Dirac materials.
Rodriguez-López, Pablo; Tse, Wang-Kong; Dalvit, Diego A R
2015-06-03
We compute the radiative heat transfer between two sheets of 2D Dirac materials, including topological Chern insulators and graphene, within the framework of the local approximation for the optical response of these materials. In this approximation, which neglects spatial dispersion, we derive both numerically and analytically the short-distance asymptotic of the near-field heat transfer in these systems, and show that it scales as the inverse of the distance between the two sheets. Finally, we discuss the limitations to the validity of this scaling law imposed by spatial dispersion in 2D Dirac materials.
Quantum process tomography by 2D fluorescence spectroscopy
Pachón, Leonardo A.; Marcus, Andrew H.; Aspuru-Guzik, Alán
2015-06-07
Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter Γ of the doubly excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed.
Radiative heat transfer in 2D Dirac materials
Rodriguez-López, Pablo; Tse, Wang -Kong; Dalvit, Diego A. R.
2015-05-12
We compute the radiative heat transfer between two sheets of 2D Dirac materials, including topological Chern insulators and graphene, within the framework of the local approximation for the optical response of these materials. In this approximation, which neglects spatial dispersion, we derive both numerically and analytically the short-distance asymptotic of the near-field heat transfer in these systems, and show that it scales as the inverse of the distance between the two sheets. In conclusion, we discuss the limitations to the validity of this scaling law imposed by spatial dispersion in 2D Dirac materials.
Experimental validation of equations for 2D DIC uncertainty quantification.
Reu, Phillip L.; Miller, Timothy J.
2010-03-01
Uncertainty quantification (UQ) equations have been derived for predicting matching uncertainty in two-dimensional image correlation a priori. These equations include terms that represent the image noise and image contrast. Researchers at the University of South Carolina have extended previous 1D work to calculate matching errors in 2D. These 2D equations have been coded into a Sandia National Laboratories UQ software package to predict the uncertainty for DIC images. This paper presents those equations and the resulting error surfaces for trial speckle images. Comparison of the UQ results with experimentally subpixel-shifted images is also discussed.
Scale Invariance in 2D BCS-BEC Crossover
NASA Astrophysics Data System (ADS)
Sensarma, Rajdeep; Taylor, Edward; Randeria, Mohit
2013-03-01
In 2D BCS-BEC crossover, the frequency of the breathing mode in a harmonic trap, as well as the lower edge of the radio frequency spectroscopy response, show remarkable scale-invariance throughout the crossover regime, i.e. they are independent of the coupling constant. Using functional integral methods, we study the behaviour of these quantities in the 2D BCS-BEC crossover and comment on the possible reasons for this scale independence. RS was supported by DAE, Govt. of India. MR was supported by NSF Grant No. DMR-1006532. ET was supported by NSERC and the Canadian Institute for Advanced Research.
Closed-shell and open-shell 2D nanographenes.
Sun, Zhe; Wu, Jishan
2014-01-01
This chapter describes a series of two-dimensional (2D) expanded arene networks, also known as nanographenes, with either closed-shell or open-shell electronic structure in the ground state. These systems are further categorized into three classes on a basis of different edge structures: those with zigzag edges only, those with armchair edges only, and those possessing both. Distinctive physical properties of these 2D aromatic systems are closely related to their structural characteristics and provide great potential for them as materials for different applications.
2D Log-Gabor Wavelet Based Action Recognition
NASA Astrophysics Data System (ADS)
Li, Ning; Xu, De
The frequency response of log-Gabor function matches well the frequency response of primate visual neurons. In this letter, motion-salient regions are extracted based on the 2D log-Gabor wavelet transform of the spatio-temporal form of actions. A supervised classification technique is then used to classify the actions. The proposed method is robust to the irregular segmentation of actors. Moreover, the 2D log-Gabor wavelet permits more compact representation of actions than the recent neurobiological models using Gabor wavelet.
NASA Astrophysics Data System (ADS)
Tønning, Erik; Polders, Daniel; Callaghan, Paul T.; Engelsen, Søren B.
2007-09-01
This paper demonstrates how the multi-linear PARAFAC model can with advantage be used to decompose 2D diffusion-relaxation correlation NMR spectra prior to 2D-Laplace inversion to the T2- D domain. The decomposition is advantageous for better interpretation of the complex correlation maps as well as for the quantification of extracted T2- D components. To demonstrate the new method seventeen mixtures of wheat flour, starch, gluten, oil and water were prepared and measured with a 300 MHz nuclear magnetic resonance (NMR) spectrometer using a pulsed gradient stimulated echo (PGSTE) pulse sequence followed by a Carr-Purcell-Meiboom-Gill (CPMG) pulse echo train. By varying the gradient strength, 2D diffusion-relaxation data were recorded for each sample. From these double exponentially decaying relaxation data the PARAFAC algorithm extracted two unique diffusion-relaxation components, explaining 99.8% of the variation in the data set. These two components were subsequently transformed to the T2- D domain using 2D-inverse Laplace transformation and quantitatively assigned to the oil and water components of the samples. The oil component was one distinct distribution with peak intensity at D = 3 × 10 -12 m 2 s -1 and T2 = 180 ms. The water component consisted of two broad populations of water molecules with diffusion coefficients and relaxation times centered around correlation pairs: D = 10 -9 m 2 s -1, T2 = 10 ms and D = 3 × 10 -13 m 2 s -1, T2 = 13 ms. Small spurious peaks observed in the inverse Laplace transformation of original complex data were effectively filtered by the PARAFAC decomposition and thus considered artefacts from the complex Laplace transformation. The oil-to-water ratio determined by PARAFAC followed by 2D-Laplace inversion was perfectly correlated with known oil-to-water ratio of the samples. The new method of using PARAFAC prior to the 2D-Laplace inversion proved to have superior potential in analysis of diffusion-relaxation spectra, as it
Rowley-Neale, Samuel J; Fearn, Jamie M; Brownson, Dale A C; Smith, Graham C; Ji, Xiaobo; Banks, Craig E
2016-08-21
Two-dimensional molybdenum disulphide nanosheets (2D-MoS2) have proven to be an effective electrocatalyst, with particular attention being focused on their use towards increasing the efficiency of the reactions associated with hydrogen fuel cells. Whilst the majority of research has focused on the Hydrogen Evolution Reaction (HER), herein we explore the use of 2D-MoS2 as a potential electrocatalyst for the much less researched Oxygen Reduction Reaction (ORR). We stray from literature conventions and perform experiments in 0.1 M H2SO4 acidic electrolyte for the first time, evaluating the electrochemical performance of the ORR with 2D-MoS2 electrically wired/immobilised upon several carbon based electrodes (namely; Boron Doped Diamond (BDD), Edge Plane Pyrolytic Graphite (EPPG), Glassy Carbon (GC) and Screen-Printed Electrodes (SPE)) whilst exploring a range of 2D-MoS2 coverages/masses. Consequently, the findings of this study are highly applicable to real world fuel cell applications. We show that significant improvements in ORR activity can be achieved through the careful selection of the underlying/supporting carbon materials that electrically wire the 2D-MoS2 and utilisation of an optimal mass of 2D-MoS2. The ORR onset is observed to be reduced to ca. +0.10 V for EPPG, GC and SPEs at 2D-MoS2 (1524 ng cm(-2) modification), which is far closer to Pt at +0.46 V compared to bare/unmodified EPPG, GC and SPE counterparts. This report is the first to demonstrate such beneficial electrochemical responses in acidic conditions using a 2D-MoS2 based electrocatalyst material on a carbon-based substrate (SPEs in this case). Investigation of the beneficial reaction mechanism reveals the ORR to occur via a 4 electron process in specific conditions; elsewhere a 2 electron process is observed. This work offers valuable insights for those wishing to design, fabricate and/or electrochemically test 2D-nanosheet materials towards the ORR.
Anistratov, Dmitriy Y.; Adams, Marvin L.; Palmer, Todd S.; Smith, Kord S.
2000-07-25
The status summary of Nuclear Energy Research Initiative (NERI) Tasks - Phase 1 are: Task 1--The development of the following methods in 1D slab geometry: (1) Homogenization and definition of discontinuity factors, (2) Group constants functionalization using assembly transport solution of multigroup eigenvalue problem with albedo boundary conditions, and (3) solving coarse-mesh effective few-group 1D QD moment equations using tables of data parameterized with respect to the ratio {rvec n} {center_dot} {rvec J}{sup G}/{tilde {phi}{sup G}} on boundaries. Status summary of NERI Tasks - Phase 1: Task 2--Development of a numerical method for solving the 2D few-group moment QD equations: (1) Development of a nodal discretization method for 2D moment QD equations, and (2) Development of an efficient iteration method for solving the system of equations of the nodal discretization method for 2D moment QD equations.
Muonic hydrogen and the third Zemach moment
Friar, J.L.; Sick, Ingo
2005-10-15
We determine the third Zemach moment of hydrogen (
Gross shell structure of moments of inertia
Deleplanque, M.A.; Frauendorf, S.; Pashkevich, V.V.; Chu, S.Y.; Unzhakova, A.
2002-07-01
Average yrast moments of inertia at high spins, where the pairing correlations are expected to be largely absent, were found to deviate from the rigid-body values. This indicates that shell effects contribute to the moment of inertia. We discuss the gross dependence of moments of inertia and shell energies on the neutron number in terms of the semiclassical periodic orbit theory. We show that the ground-state shell energies, nuclear deformations and deviations from rigid-body moments of inertia are all due to the same periodic orbits.
New experiment to measure the electron electric dipole moment
NASA Astrophysics Data System (ADS)
Kittle, M.; Burton, T.; Feeney, L.; Heinzen, D. J.
2004-05-01
We are building a new experiment to measure the electric dipole moment (edm) of the electron. The experiment will use laser-cooled Cs atoms trapped in two, side-by-side, standing wave, far-off resonance optical dipole force traps. High voltage electrodes will apply opposite polarity electric fields to the two traps. The signature of an edm would be a first-order electric field shift of the atomic Zeeman levels. The traps will be loaded inside a titanium vacuum chamber with atoms captured in optical molasses from a 2D MOT cold atom source. We have paid special attention to the magnetic noise generated by Johnson noise currents of conductors in the design of this apparatus. The apparatus is designed to be sensitive to an electron edm as small as 10-29 e cm. In this presentation, we will discuss the design of our experiment and our experimental progress.
Discrepant Results in a 2-D Marble Collision
ERIC Educational Resources Information Center
Kalajian, Peter
2013-01-01
Video analysis of 2-D collisions is an excellent way to investigate conservation of linear momentum. The often-desired experimental design goal is to minimize the momentum loss in order to demonstrate the conservation law. An air table with colliding pucks is an ideal medium for this experiment, but such equipment is beyond the budget of many…
2-D Finite Element Cable and Box IEMP Analysis
Scivner, G.J.; Turner, C.D.
1998-12-17
A 2-D finite element code has been developed for the solution of arbitrary geometry cable SGEMP and box IEMP problems. The quasi- static electric field equations with radiation- induced charge deposition and radiation-induced conductivity y are numerically solved on a triangular mesh. Multiple regions of different dielectric materials and multiple conductors are permitted.
2D Orthogonal Locality Preserving Projection for Image Denoising.
Shikkenawis, Gitam; Mitra, Suman K
2016-01-01
Sparse representations using transform-domain techniques are widely used for better interpretation of the raw data. Orthogonal locality preserving projection (OLPP) is a linear technique that tries to preserve local structure of data in the transform domain as well. Vectorized nature of OLPP requires high-dimensional data to be converted to vector format, hence may lose spatial neighborhood information of raw data. On the other hand, processing 2D data directly, not only preserves spatial information, but also improves the computational efficiency considerably. The 2D OLPP is expected to learn the transformation from 2D data itself. This paper derives mathematical foundation for 2D OLPP. The proposed technique is used for image denoising task. Recent state-of-the-art approaches for image denoising work on two major hypotheses, i.e., non-local self-similarity and sparse linear approximations of the data. Locality preserving nature of the proposed approach automatically takes care of self-similarity present in the image while inferring sparse basis. A global basis is adequate for the entire image. The proposed approach outperforms several state-of-the-art image denoising approaches for gray-scale, color, and texture images.
2D signature for detection and identification of drugs
NASA Astrophysics Data System (ADS)
Trofimov, Vyacheslav A.; Varentsova, Svetlana A.; Shen, Jingling; Zhang, Cunlin; Zhou, Qingli; Shi, Yulei
2011-06-01
The method of spectral dynamics analysis (SDA-method) is used for obtaining the2D THz signature of drugs. This signature is used for the detection and identification of drugs with similar Fourier spectra by transmitted THz signal. We discuss the efficiency of SDA method for the identification problem of pure methamphetamine (MA), methylenedioxyamphetamine (MDA), 3, 4-methylenedioxymethamphetamine (MDMA) and Ketamine.
Optoelectronics of supported and suspended 2D semiconductors
NASA Astrophysics Data System (ADS)
Bolotin, Kirill
2014-03-01
Two-dimensional semiconductors, materials such monolayer molybdenum disulfide (MoS2) are characterized by strong spin-orbit and electron-electron interactions. However, both electronic and optoelectronic properties of these materials are dominated by disorder-related scattering. In this talk, we investigate approaches to reduce scattering and explore physical phenomena arising in intrinsic 2D semiconductors. First, we discuss fabrication of pristine suspended monolayer MoS2 and use photocurrent spectroscopy measurements to study excitons in this material. We observe band-edge and van Hove singularity excitons and estimate their binding energies. Furthermore, we study dissociation of these excitons and uncover the mechanism of their contribution to photoresponse of MoS2. Second, we study strain-induced modification of bandstructures of 2D semiconductors. With increasing strain, we find large and controllable band gap reduction of both single- and bi-layer MoS2. We also detect experimental signatures consistent with strain-induced transition from direct to indirect band gap in monolayer MoS2. Finally, we fabricate heterostructures of dissimilar 2D semiconductors and study their photoresponse. For closely spaced 2D semiconductors we detect charge transfer, while for separation larger than 10nm we observe Forster-like energy transfer between excitations in different layers.
Graphene band structure and its 2D Raman mode
NASA Astrophysics Data System (ADS)
Narula, Rohit; Reich, Stephanie
2014-08-01
High-precision simulations are used to generate the 2D Raman mode of graphene under a range of screening conditions and laser energies EL. We reproduce the decreasing trend of the 2D mode FWHM vs EL and the nearly linearly increasing dispersion ∂ω2D/∂EL seen experimentally in freestanding (unscreened) graphene, and propose relations between these experimentally accessible quantities and the local, two-dimensional gradients |∇ | of the electronic and TO phonon bands. In light of state-of-the-art electronic structure calculations that acutely treat the long-range e-e interactions of isolated graphene and its experimentally observed 2D Raman mode, our calculations determine a 40% greater slope of the TO phonons about K than given by explicit phonon measurements performed in graphite or GW phonon calculations in graphene. We also deduce the variation of the broadening energy γ [EL] for freestanding graphene and find a nominal value γ ˜140 meV, showing a gradually increasing trend for the range of frequencies available experimentally.
Development of a MEMS 2D separations device
NASA Astrophysics Data System (ADS)
Bloschock, Kristen P.; Flyer, Jonathan N.; Schneider, Thomas W.; Hussam, Abul; Van Keuren, Edward R.
2004-12-01
A polymer based biochip for rapid 2D separations of peptides, proteins, and other biomedically relevant molecules was designed and fabricated. Like traditional 2D polyacrylamide gel electrophoresis (2D-PAGE) methods, the device will allow molecules to separate based on isoelectric point (pI) and molecular weight (MW). Our design, however, integrates both an initial capillary isoelectric focusing (cIEF) step followed by capillary electrophoresis (CE) in multiple parallel channels, all on a single microfluidic chip. Not only is the "lab-on-a-chip" design easier to use and less expensive, but the miniaturization of the device produces very rapid separations. Compared to traditional 2D-PAGE, which can take hours to complete, we estimate separation times on the order of seconds. Fluorescence detection will be used in the preliminary stages of testing, but the device also is equipped with integrated electrodes in the electrophoresis channels to perform multiplexed electrochemical detection for quantitative analysis. We will present preliminary results of the chip development and testing.
The 2dF Galaxy Redshift Survey: Preliminary Results
NASA Astrophysics Data System (ADS)
Maddox, Steve; 2DF Galaxy Redshift Survey Team; Bland-Hawthorn, Joss; Cannon, Russell; Cole, Shaun; Colless, Matthew; Collins, Chris; Couch, Warrick; Dalton, Gavin; Driver, Simon; Ellis, Richard; Efstathiou, George; Folkes, Simon; Frenk, Carlos; Glazebrook, Karl; Kaiser, Nick; Lahav, Ofer; Lumsden, Stuart; Peterson, Bruce; Peacock, John; Sutherland, Will; Taylor, Keith
Spectroscopic observations for a new survey of 250 000 galaxy redshifts are underway, using the 2dF instrument at the AAT. The input galaxy catalogue and commissioning data are described. The first result from the preliminary data is a new estimate of the galaxy luminosity function at
Volume Calculation of Venous Thrombosis Using 2D Ultrasound Images.
Dhibi, M; Puentes, J; Bressollette, L; Guias, B; Solaiman, B
2005-01-01
Venous thrombosis screening exams use 2D ultrasound images, from which medical experts obtain a rough idea of the thrombosis aspect and infer an approximate volume. Such estimation is essential to follow up the thrombosis evolution. This paper proposes a method to calculate venous thrombosis volume from non-parallel 2D ultrasound images, taking advantage of a priori knowledge about the thrombosis shape. An interactive ellipse fitting contour segmentation extracts the 2D thrombosis contours. Then, a Delaunay triangulation is applied to the set of 2D segmented contours positioned in 3D, and the area that each contour defines, to obtain a global thrombosis 3D surface reconstruction, with a dense triangulation inside the contours. Volume is calculated from the obtained surface and contours triangulation, using a maximum unit normal component approach. Preliminary results obtained on 3 plastic phantoms and 3 in vitro venous thromboses, as well as one in vivo case are presented and discussed. An error rate of volume estimation inferior to 4,5% for the plastic phantoms, and 3,5% for the in vitro venous thromboses was obtained.
ELLIPT2D: A Flexible Finite Element Code Written Python
Pletzer, A.; Mollis, J.C.
2001-03-22
The use of the Python scripting language for scientific applications and in particular to solve partial differential equations is explored. It is shown that Python's rich data structure and object-oriented features can be exploited to write programs that are not only significantly more concise than their counter parts written in Fortran, C or C++, but are also numerically efficient. To illustrate this, a two-dimensional finite element code (ELLIPT2D) has been written. ELLIPT2D provides a flexible and easy-to-use framework for solving a large class of second-order elliptic problems. The program allows for structured or unstructured meshes. All functions defining the elliptic operator are user supplied and so are the boundary conditions, which can be of Dirichlet, Neumann or Robbins type. ELLIPT2D makes extensive use of dictionaries (hash tables) as a way to represent sparse matrices.Other key features of the Python language that have been widely used include: operator over loading, error handling, array slicing, and the Tkinter module for building graphical use interfaces. As an example of the utility of ELLIPT2D, a nonlinear solution of the Grad-Shafranov equation is computed using a Newton iterative scheme. A second application focuses on a solution of the toroidal Laplace equation coupled to a magnetohydrodynamic stability code, a problem arising in the context of magnetic fusion research.
Rheological Properties of Quasi-2D Fluids in Microgravity
NASA Technical Reports Server (NTRS)
Stannarius, Ralf; Trittel, Torsten; Eremin, Alexey; Harth, Kirsten; Clark, Noel; Maclennan, Joseph; Glaser, Matthew; Park, Cheol; Hall, Nancy; Tin, Padetha
2015-01-01
In recent years, research on complex fluids and fluids in restricted geometries has attracted much attention in the scientific community. This can be attributed not only to the development of novel materials based on complex fluids but also to a variety of important physical phenomena which have barely been explored. One example is the behavior of membranes and thin fluid films, which can be described by two-dimensional (2D) rheology behavior that is quite different from 3D fluids. In this study, we have investigated the rheological properties of freely suspended films of a thermotropic liquid crystal in microgravity experiments. This model system mimics isotropic and anisotropic quasi 2D fluids [46]. We use inkjet printing technology to dispense small droplets (inclusions) onto the film surface. The motion of these inclusions provides information on the rheological properties of the films and allows the study of a variety of flow instabilities. Flat films have been investigated on a sub-orbital rocket flight and curved films (bubbles) have been studied in the ISS project OASIS. Microgravity is essential when the films are curved in order to avoid sedimentation. The experiments yield the mobility of the droplets in the films as well as the mutual mobility of pairs of particles. Experimental results will be presented for 2D-isotropic (smectic-A) and 2D-nematic (smectic-C) phases.
Validation and testing of the VAM2D computer code
Kool, J.B.; Wu, Y.S. )
1991-10-01
This document describes two modeling studies conducted by HydroGeoLogic, Inc. for the US NRC under contract no. NRC-04089-090, entitled, Validation and Testing of the VAM2D Computer Code.'' VAM2D is a two-dimensional, variably saturated flow and transport code, with applications for performance assessment of nuclear waste disposal. The computer code itself is documented in a separate NUREG document (NUREG/CR-5352, 1989). The studies presented in this report involve application of the VAM2D code to two diverse subsurface modeling problems. The first one involves modeling of infiltration and redistribution of water and solutes in an initially dry, heterogeneous field soil. This application involves detailed modeling over a relatively short, 9-month time period. The second problem pertains to the application of VAM2D to the modeling of a waste disposal facility in a fractured clay, over much larger space and time scales and with particular emphasis on the applicability and reliability of using equivalent porous medium approach for simulating flow and transport in fractured geologic media. Reflecting the separate and distinct nature of the two problems studied, this report is organized in two separate parts. 61 refs., 31 figs., 9 tabs.
NKG2D ligands mediate immunosurveillance of senescent cells
Moshayev, Zhana; Vadai, Ezra; Wensveen, Felix; Ben-Dor, Shifra; Golani, Ofra; Polic, Bojan; Krizhanovsky, Valery
2016-01-01
Cellular senescence is a stress response mechanism that limits tumorigenesis and tissue damage. Induction of cellular senescence commonly coincides with an immunogenic phenotype that promotes self-elimination by components of the immune system, thereby facilitating tumor suppression and limiting excess fibrosis during wound repair. The mechanisms by which senescent cells regulate their immune surveillance are not completely understood. Here we show that ligands of an activating Natural Killer (NK) cell receptor (NKG2D), MICA and ULBP2 are consistently up-regulated following induction of replicative senescence, oncogene-induced senescence and DNA damage - induced senescence. MICA and ULBP2 proteins are necessary for efficient NK-mediated cytotoxicity towards senescent fibroblasts. The mechanisms regulating the initial expression of NKG2D ligands in senescent cells are dependent on a DNA damage response, whilst continuous expression of these ligands is regulated by the ERK signaling pathway. In liver fibrosis, the accumulation of senescent activated stellate cells is increased in mice lacking NKG2D receptor leading to increased fibrosis. Overall, our results provide new insights into the mechanisms regulating the expression of immune ligands in senescent cells and reveal the importance of NKG2D receptor-ligand interaction in protecting against liver fibrosis. PMID:26878797
Studying Zeolite Catalysts with a 2D Model System
Boscoboinik, Anibal
2016-12-14
Anibal Boscoboinik, a materials scientist at Brookhavenâs Center for Functional Nanomaterials, discusses the surface-science tools and 2D model system he uses to study catalysis in nanoporous zeolites, which catalyze reactions in many industrial processes.
2D nanomaterials based electrochemical biosensors for cancer diagnosis.
Wang, Lu; Xiong, Qirong; Xiao, Fei; Duan, Hongwei
2017-03-15
Cancer is a leading cause of death in the world. Increasing evidence has demonstrated that early diagnosis holds the key towards effective treatment outcome. Cancer biomarkers are extensively used in oncology for cancer diagnosis and prognosis. Electrochemical sensors play key roles in current laboratory and clinical analysis of diverse chemical and biological targets. Recent development of functional nanomaterials offers new possibilities of improving the performance of electrochemical sensors. In particular, 2D nanomaterials have stimulated intense research due to their unique array of structural and chemical properties. The 2D materials of interest cover broadly across graphene, graphene derivatives (i.e., graphene oxide and reduced graphene oxide), and graphene-like nanomaterials (i.e., 2D layered transition metal dichalcogenides, graphite carbon nitride and boron nitride nanomaterials). In this review, we summarize recent advances in the synthesis of 2D nanomaterials and their applications in electrochemical biosensing of cancer biomarkers (nucleic acids, proteins and some small molecules), and present a personal perspective on the future direction of this area.
NASA Astrophysics Data System (ADS)
Rowley-Neale, Samuel J.; Fearn, Jamie M.; Brownson, Dale A. C.; Smith, Graham C.; Ji, Xiaobo; Banks, Craig E.
2016-08-01
Two-dimensional molybdenum disulphide nanosheets (2D-MoS2) have proven to be an effective electrocatalyst, with particular attention being focused on their use towards increasing the efficiency of the reactions associated with hydrogen fuel cells. Whilst the majority of research has focused on the Hydrogen Evolution Reaction (HER), herein we explore the use of 2D-MoS2 as a potential electrocatalyst for the much less researched Oxygen Reduction Reaction (ORR). We stray from literature conventions and perform experiments in 0.1 M H2SO4 acidic electrolyte for the first time, evaluating the electrochemical performance of the ORR with 2D-MoS2 electrically wired/immobilised upon several carbon based electrodes (namely; Boron Doped Diamond (BDD), Edge Plane Pyrolytic Graphite (EPPG), Glassy Carbon (GC) and Screen-Printed Electrodes (SPE)) whilst exploring a range of 2D-MoS2 coverages/masses. Consequently, the findings of this study are highly applicable to real world fuel cell applications. We show that significant improvements in ORR activity can be achieved through the careful selection of the underlying/supporting carbon materials that electrically wire the 2D-MoS2 and utilisation of an optimal mass of 2D-MoS2. The ORR onset is observed to be reduced to ca. +0.10 V for EPPG, GC and SPEs at 2D-MoS2 (1524 ng cm-2 modification), which is far closer to Pt at +0.46 V compared to bare/unmodified EPPG, GC and SPE counterparts. This report is the first to demonstrate such beneficial electrochemical responses in acidic conditions using a 2D-MoS2 based electrocatalyst material on a carbon-based substrate (SPEs in this case). Investigation of the beneficial reaction mechanism reveals the ORR to occur via a 4 electron process in specific conditions; elsewhere a 2 electron process is observed. This work offers valuable insights for those wishing to design, fabricate and/or electrochemically test 2D-nanosheet materials towards the ORR.Two-dimensional molybdenum disulphide nanosheets
Giaddui, T; Yu, J; Xiao, Y; Jacobs, P; Manfredi, D; Linnemann, N
2015-06-15
Purpose: 2D-2D kV image guided radiation therapy (IGRT) credentialing evaluation for clinical trial qualification was historically qualitative through submitting screen captures of the fusion process. However, as quantitative DICOM 2D-2D and 2D-3D image registration tools are implemented in clinical practice for better precision, especially in centers that treat patients with protons, better IGRT credentialing techniques are needed. The aim of this work is to establish methodologies for quantitatively reviewing IGRT submissions based on DICOM 2D-2D and 2D-3D image registration and to test the methodologies in reviewing 2D-2D and 2D-3D IGRT submissions for RTOG/NRG Oncology clinical trials qualifications. Methods: DICOM 2D-2D and 2D-3D automated and manual image registration have been tested using the Harmony tool in MIM software. 2D kV orthogonal portal images are fused with the reference digital reconstructed radiographs (DRR) in the 2D-2D registration while the 2D portal images are fused with DICOM planning CT image in the 2D-3D registration. The Harmony tool allows alignment of the two images used in the registration process and also calculates the required shifts. Shifts calculated using MIM are compared with those submitted by institutions for IGRT credentialing. Reported shifts are considered to be acceptable if differences are less than 3mm. Results: Several tests have been performed on the 2D-2D and 2D-3D registration. The results indicated good agreement between submitted and calculated shifts. A workflow for reviewing these IGRT submissions has been developed and will eventually be used to review IGRT submissions. Conclusion: The IROC Philadelphia RTQA center has developed and tested a new workflow for reviewing DICOM 2D-2D and 2D-3D IGRT credentialing submissions made by different cancer clinical centers, especially proton centers. NRG Center for Innovation in Radiation Oncology (CIRO) and IROC RTQA center continue their collaborative efforts to enhance
Half-metallicity in 2D organometallic honeycomb frameworks.
Sun, Hao; Li, Bin; Zhao, Jin
2016-10-26
Half-metallic materials with a high Curie temperature (T C) have many potential applications in spintronics. Magnetic metal free two-dimensional (2D) half-metallic materials with a honeycomb structure contain graphene-like Dirac bands with π orbitals and show excellent aspects in transport properties. In this article, by investigating a series of 2D organometallic frameworks with a honeycomb structure using first principles calculations, we study the origin of forming half-metallicity in this kind of 2D organometallic framework. Our analysis shows that charge transfer and covalent bonding are two crucial factors in the formation of half-metallicity in organometallic frameworks. (i) Sufficient charge transfer from metal atoms to the molecules is essential to form the magnetic centers. (ii) These magnetic centers need to be connected through covalent bonding, which guarantee the strong ferromagnetic (FM) coupling. As examples, the organometallic frameworks composed by (1,3,5)-benzenetricarbonitrile (TCB) molecules with noble metals (Au, Ag, Cu) show half-metallic properties with T C as high as 325 K. In these organometallic frameworks, the strong electronegative cyano-groups (CN groups) drive the charge transfer from metal atoms to the TCB molecules, forming the local magnetic centers. These magnetic centers experience strong FM coupling through the d-p covalent bonding. We propose that most of the 2D organometallic frameworks composed by molecule-CN-noble metal honeycomb structures contain similar half metallicity. This is verified by replacing TCB molecules with other organic molecules. Although the TCB-noble metal organometallic framework has not yet been synthesized, we believe the development of synthesizing techniques and facility will enable the realization of them. Our study provides new insight into the 2D half-metallic material design for the potential applications in nanotechnology.
2d-LCA - an alternative to x-wires
NASA Astrophysics Data System (ADS)
Puczylowski, Jaroslaw; Hölling, Michael; Peinke, Joachim
2014-11-01
The 2d-Laser Cantilever Anemometer (2d-LCA) is an innovative sensor for two-dimensional velocity measurements in fluids. It uses a micostructured cantilever made of silicon and SU-8 as a sensing element and is capable of performing mesurements with extremly high temporal resolutions up to 150 kHz. The size of the cantilever defines its spatial resolution, which is in the order of 150 μm only. Another big feature is a large angular range of 180° in total. The 2d-LCA has been developed as an alternative measurement method to x-wires with the motivation to create a sensor that can operate in areas where the use of hot-wire anemometry is difficult. These areas include measurements in liquids and in near-wall or particle-laden flows. Unlike hot-wires, the resolution power of the 2d-LCA does not decrease with increasing flow velocity, making it particularly suitable for measurements in high speed flows. Comparative measurements with the 2d-LCA and hot-wires have been carried out in order to assess the performance of the new anemometer. The data of both measurement techniques were analyzed using the same stochastic methods including a spectral analysis as well as an inspection of increment statistics and structure functions. Furthermore, key parameters, such as mean values of both velocity components, angles of attack and the characteristic length scales were determined from both data sets. The analysis reveals a great agreement between both anemometers and thus confirms the new approach.
2D/3D Image Registration using Regression Learning
Chou, Chen-Rui; Frederick, Brandon; Mageras, Gig; Chang, Sha; Pizer, Stephen
2013-01-01
In computer vision and image analysis, image registration between 2D projections and a 3D image that achieves high accuracy and near real-time computation is challenging. In this paper, we propose a novel method that can rapidly detect an object’s 3D rigid motion or deformation from a 2D projection image or a small set thereof. The method is called CLARET (Correction via Limited-Angle Residues in External Beam Therapy) and consists of two stages: registration preceded by shape space and regression learning. In the registration stage, linear operators are used to iteratively estimate the motion/deformation parameters based on the current intensity residue between the target projec-tion(s) and the digitally reconstructed radiograph(s) (DRRs) of the estimated 3D image. The method determines the linear operators via a two-step learning process. First, it builds a low-order parametric model of the image region’s motion/deformation shape space from its prior 3D images. Second, using learning-time samples produced from the 3D images, it formulates the relationships between the model parameters and the co-varying 2D projection intensity residues by multi-scale linear regressions. The calculated multi-scale regression matrices yield the coarse-to-fine linear operators used in estimating the model parameters from the 2D projection intensity residues in the registration. The method’s application to Image-guided Radiation Therapy (IGRT) requires only a few seconds and yields good results in localizing a tumor under rigid motion in the head and neck and under respiratory deformation in the lung, using one treatment-time imaging 2D projection or a small set thereof. PMID:24058278
Half-metallicity in 2D organometallic honeycomb frameworks
NASA Astrophysics Data System (ADS)
Sun, Hao; Li, Bin; Zhao, Jin
2016-10-01
Half-metallic materials with a high Curie temperature (T C) have many potential applications in spintronics. Magnetic metal free two-dimensional (2D) half-metallic materials with a honeycomb structure contain graphene-like Dirac bands with π orbitals and show excellent aspects in transport properties. In this article, by investigating a series of 2D organometallic frameworks with a honeycomb structure using first principles calculations, we study the origin of forming half-metallicity in this kind of 2D organometallic framework. Our analysis shows that charge transfer and covalent bonding are two crucial factors in the formation of half-metallicity in organometallic frameworks. (i) Sufficient charge transfer from metal atoms to the molecules is essential to form the magnetic centers. (ii) These magnetic centers need to be connected through covalent bonding, which guarantee the strong ferromagnetic (FM) coupling. As examples, the organometallic frameworks composed by (1,3,5)-benzenetricarbonitrile (TCB) molecules with noble metals (Au, Ag, Cu) show half-metallic properties with T C as high as 325 K. In these organometallic frameworks, the strong electronegative cyano-groups (CN groups) drive the charge transfer from metal atoms to the TCB molecules, forming the local magnetic centers. These magnetic centers experience strong FM coupling through the d-p covalent bonding. We propose that most of the 2D organometallic frameworks composed by molecule—CN—noble metal honeycomb structures contain similar half metallicity. This is verified by replacing TCB molecules with other organic molecules. Although the TCB-noble metal organometallic framework has not yet been synthesized, we believe the development of synthesizing techniques and facility will enable the realization of them. Our study provides new insight into the 2D half-metallic material design for the potential applications in nanotechnology.
A scanning-mode 2D shear wave imaging (s2D-SWI) system for ultrasound elastography.
Qiu, Weibao; Wang, Congzhi; Li, Yongchuan; Zhou, Juan; Yang, Ge; Xiao, Yang; Feng, Ge; Jin, Qiaofeng; Mu, Peitian; Qian, Ming; Zheng, Hairong
2015-09-01
Ultrasound elastography is widely used for the non-invasive measurement of tissue elasticity properties. Shear wave imaging (SWI) is a quantitative method for assessing tissue stiffness. SWI has been demonstrated to be less operator dependent than quasi-static elastography, and has the ability to acquire quantitative elasticity information in contrast with acoustic radiation force impulse (ARFI) imaging. However, traditional SWI implementations cannot acquire two dimensional (2D) quantitative images of the tissue elasticity distribution. This study proposes and evaluates a scanning-mode 2D SWI (s2D-SWI) system. The hardware and image processing algorithms are presented in detail. Programmable devices are used to support flexible control of the system and the image processing algorithms. An analytic signal based cross-correlation method and a Radon transformation based shear wave speed determination method are proposed, which can be implemented using parallel computation. Imaging of tissue mimicking phantoms, and in vitro, and in vivo imaging test are conducted to demonstrate the performance of the proposed system. The s2D-SWI system represents a new choice for the quantitative mapping of tissue elasticity, and has great potential for implementation in commercial ultrasound scanners.
2D-2D tunneling field-effect transistors using WSe2/SnSe2 heterostructures
NASA Astrophysics Data System (ADS)
Roy, Tania; Tosun, Mahmut; Hettick, Mark; Ahn, Geun Ho; Hu, Chenming; Javey, Ali
2016-02-01
Two-dimensional materials present a versatile platform for developing steep transistors due to their uniform thickness and sharp band edges. We demonstrate 2D-2D tunneling in a WSe2/SnSe2 van der Waals vertical heterojunction device, where WSe2 is used as the gate controlled p-layer and SnSe2 is the degenerately n-type layer. The van der Waals gap facilitates the regulation of band alignment at the heterojunction, without the necessity of a tunneling barrier. ZrO2 is used as the gate dielectric, allowing the scaling of gate oxide to improve device subthreshold swing. Efficient gate control and clean interfaces yield a subthreshold swing of ˜100 mV/dec for >2 decades of drain current at room temperature, hitherto unobserved in 2D-2D tunneling devices. The subthreshold swing is independent of temperature, which is a clear signature of band-to-band tunneling at the heterojunction. A maximum switching ratio ION/IOFF of 107 is obtained. Negative differential resistance in the forward bias characteristics is observed at 77 K. This work bodes well for the possibilities of two-dimensional materials for the realization of energy-efficient future-generation electronics.
How to Introduce the Magnetic Dipole Moment
ERIC Educational Resources Information Center
Bezerra, M.; Kort-Kamp, W. J. M.; Cougo-Pinto, M. V.; Farina, C.
2012-01-01
We show how the concept of the magnetic dipole moment can be introduced in the same way as the concept of the electric dipole moment in introductory courses on electromagnetism. Considering a localized steady current distribution, we make a Taylor expansion directly in the Biot-Savart law to obtain, explicitly, the dominant contribution of the…
The classical model for moment tensors
NASA Astrophysics Data System (ADS)
Tape, Walter; Tape, Carl
2013-12-01
A seismic moment tensor is a description of an earthquake source, but the description is indirect. The moment tensor describes seismic radiation rather than the actual physical process that initiates the radiation. A moment tensor `model' then ties the physical process to the moment tensor. The model is not unique, and the physical process is therefore not unique. In the classical moment tensor model, an earthquake arises from slip along a planar fault, but with the slip not necessarily in the plane of the fault. The model specifies the resulting moment tensor in terms of the slip vector, the fault normal vector and the Lamé elastic parameters, assuming isotropy. We review the classical model in the context of the fundamental lune. The lune is closely related to the space of moment tensors, and it provides a setting that is conceptually natural as well as pictorial. In addition to the classical model, we consider a crack plus double-couple model (CDC model) in which a moment tensor is regarded as the sum of a crack tensor and a double couple.
Balancing Beams--For a Few Moments
ERIC Educational Resources Information Center
Kibble, Bob
2008-01-01
A 2 m long wooden beam provides an ideal demonstration tool for exploring moments. A class set is cheap and can be used at introductory and advanced levels. This article explores how such beams can be used to support learning about moments, equilibrium, vectors, and simultaneous equations. (Contains 7 figures.)
Teachable Moment: Google Earth Takes Us There
ERIC Educational Resources Information Center
Williams, Ann; Davinroy, Thomas C.
2015-01-01
In the current educational climate, where clearly articulated learning objectives are required, it is clear that the spontaneous teachable moment still has its place. Authors Ann Williams and Thomas Davinroy think that instructors from almost any discipline can employ Google Earth as a tool to take advantage of teachable moments through the…
Moments from Cumulants and Vice Versa
ERIC Educational Resources Information Center
Withers, Christopher S.; Nadarajah, Saralees
2009-01-01
Moments and cumulants are expressed in terms of each other using Bell polynomials. Inbuilt routines for the latter make these expressions amenable to use by algebraic manipulation programs. One of the four formulas given is an explicit version of Kendall's use of Faa di Bruno's chain rule to express cumulants in terms of moments.
Joint moments of proper delay times
Martínez-Argüello, Angel M.; Martínez-Mares, Moisés; García, Julio C.
2014-08-15
We calculate negative moments of the N-dimensional Laguerre distribution for the orthogonal, unitary, and symplectic symmetries. These moments correspond to those of the proper delay times, which are needed to determine the statistical fluctuations of several transport properties through classically chaotic cavities, like quantum dots and microwave cavities with ideal coupling.
Gressier, F; Verstuyft, C; Hardy, P; Becquemont, L; Corruble, E
2015-01-01
The cytochrome P450 2D6 (CYP2D6) is involved in the metabolism of most antidepressants. Comedication with a potent CYP2D6 inhibitor can convert patients with extensive metabolizer (EM) or ultra-rapid metabolizer (UM) genotypes into poor metabolizer (PM) phenotypes. Since comedication is frequent in depressed patients treated with antidepressants, we investigated the effect of the CYP2D6 composite phenotype on antidepressant efficacy, taking into account both the CYP2D6 genotype and comedication with CYP2D6 inhibitors. 87 Caucasian in patients with a major depressive episode were prospectively treated with flexible doses of antidepressant monotherapy as well as comedications and genotyped for the major CYP2D6 alleles (CYP2D6*3 rs35742686, *4 rs3892097, *5 del, *6 rs5030655, and *2xN). They were classified for CYP2D6 composite phenotype and assessed for antidepressant response after 4 weeks. In terms of genotypes (g), 6 subjects were UMg, 6 PMg, and 75 EMg. Ten patients were coprescribed a CYP2D6 inhibitor, resulting in the following composite phenotypes (cp): 5 UMcp, 16 PMcp, and 66 EMcp. Whereas none of the CYP2D6 genotypes were significantly associated with antidepressant response, UMcp had a lower antidepressant response than PMcp or EMcp (respectively: 39.0 ± 17.9, 50.0 ± 26.0, and 61.6 ± 23.4, p = 0.02). Despite small sample size, this study suggests that a CYP2D6 composite phenotype, taking into account both genotype and comedications with CYP2D6 inhibitors, could predict CYP2D6 substrate antidepressants response. Thus, to optimize antidepressant response, CYP2D6 genotype could be performed and comedications with CYP2D6 inhibitors should be avoided, when prescribing CYP2D6 substrate antidepressants.
2-D linear motion system. Innovative technology summary report
1998-11-01
The US Department of Energy's (DOE's) nuclear facility decontamination and decommissioning (D and D) program requires buildings to be decontaminated, decommissioned, and surveyed for radiological contamination in an expeditious and cost-effective manner. Simultaneously, the health and safety of personnel involved in the D and D activities is of primary concern. D and D workers must perform duties high off the ground, requiring the use of manlifts or scaffolding, often, in radiologically or chemically contaminated areas or in areas with limited access. Survey and decontamination instruments that are used are sometimes heavy or awkward to use, particularly when the worker is operating from a manlift or scaffolding. Finding alternative methods of performing such work on manlifts or scaffolding is important. The 2-D Linear Motion System (2-D LMS), also known as the Wall Walker{trademark}, is designed to remotely position tools and instruments on walls for use in such activities as radiation surveys, decontamination, and painting. Traditional (baseline) methods for operating equipment for these tasks require workers to perform duties on elevated platforms, sometimes several meters above the ground surface and near potential sources of contamination. The Wall Walker 2-D LMS significantly improves health and safety conditions by facilitating remote operation of equipment. The Wall Walker 2-D LMS performed well in a demonstration of its precision, accuracy, maneuverability, payload capacity, and ease of use. Thus, this innovative technology is demonstrated to be a viable alternative to standard methods of performing work on large, high walls, especially those that have potential contamination concerns. The Wall Walker was used to perform a final release radiological survey on over 167 m{sup 2} of walls. In this application, surveying using a traditional (baseline) method that employs an aerial lift for manual access was 64% of the total cost of the improved technology
Gold-standard performance for 2D hydrodynamic modeling
NASA Astrophysics Data System (ADS)
Pasternack, G. B.; MacVicar, B. J.
2013-12-01
Two-dimensional, depth-averaged hydrodynamic (2D) models are emerging as an increasingly useful tool for environmental water resources engineering. One of the remaining technical hurdles to the wider adoption and acceptance of 2D modeling is the lack of standards for 2D model performance evaluation when the riverbed undulates, causing lateral flow divergence and convergence. The goal of this study was to establish a gold-standard that quantifies the upper limit of model performance for 2D models of undulating riverbeds when topography is perfectly known and surface roughness is well constrained. A review was conducted of published model performance metrics and the value ranges exhibited by models thus far for each one. Typically predicted velocity differs from observed by 20 to 30 % and the coefficient of determination between the two ranges from 0.5 to 0.8, though there tends to be a bias toward overpredicting low velocity and underpredicting high velocity. To establish a gold standard as to the best performance possible for a 2D model of an undulating bed, two straight, rectangular-walled flume experiments were done with no bed slope and only different bed undulations and water surface slopes. One flume tested model performance in the presence of a porous, homogenous gravel bed with a long flat section, then a linear slope down to a flat pool bottom, and then the same linear slope back up to the flat bed. The other flume had a PVC plastic solid bed with a long flat section followed by a sequence of five identical riffle-pool pairs in close proximity, so it tested model performance given frequent undulations. Detailed water surface elevation and velocity measurements were made for both flumes. Comparing predicted versus observed velocity magnitude for 3 discharges with the gravel-bed flume and 1 discharge for the PVC-bed flume, the coefficient of determination ranged from 0.952 to 0.987 and the slope for the regression line was 0.957 to 1.02. Unsigned velocity
Innovative moments and change in narrative therapy.
Matos, Marlene; Santos, Anita; Gonçalves, Miguel; Martins, Carla
2009-01-01
Narrative therapy suggests that change happens by paying close attention in therapy to "unique outcomes," which are narrative details outside the main story (White & Epston, 1990). In this exploratory study, unique outcomes were analyzed in five good-outcome and five poor-outcome psychotherapy cases using the Innovative Moments Coding System (Gonçalves, Matos, & Santos, 2008). Across 127 sessions, innovative moments were coded in terms of salience and type. In accordance with the theory, results suggest that innovative moments are important to therapeutic change. Poor- and good-outcome groups have a global difference in the salience of the innovative moments. In addition, results suggest that two particular types of innovative moments are needed in narrative therapy for therapeutic change to take place: re-conceptualization and new experiences. Implications for future research using this model of analysis are discussed.
Blurred image recognition by legendre moment invariants
Zhang, Hui; Shu, Huazhong; Han, Guo-Niu; Coatrieux, Gouenou; Luo, Limin; Coatrieux, Jean-Louis
2010-01-01
Processing blurred images is a key problem in many image applications. Existing methods to obtain blur invariants which are invariant with respect to centrally symmetric blur are based on geometric moments or complex moments. In this paper, we propose a new method to construct a set of blur invariants using the orthogonal Legendre moments. Some important properties of Legendre moments for the blurred image are presented and proved. The performance of the proposed descriptors is evaluated with various point-spread functions and different image noises. The comparison of the present approach with previous methods in terms of pattern recognition accuracy is also provided. The experimental results show that the proposed descriptors are more robust to noise and have better discriminative power than the methods based on geometric or complex moments. PMID:19933003
Third Zemach moment of the proton
Cloeet, Ian C.; Miller, Gerald A.
2011-01-15
Modern electron scattering experiments have determined the proton electric form factor G{sub Ep}(Q{sup 2}) to high precision. We utilize this data, represented by the different empirical form-factor parametrizations, to compute the third Zemach moment of the proton charge distribution. We find that existing data rule out a value of the third Zemach moment large enough to explain the current puzzle with the proton charge radius, determined from the Lamb shift in muonic hydrogen. This is in contrast to the recent paper of De Rujula. We also demonstrate that the size of the third Zemach moment is largely governed by the fourth moment of the conventional charge distributions
Instantons in 2D U(1) Higgs model and 2D CP(N-1) sigma models
NASA Astrophysics Data System (ADS)
Lian, Yaogang
2007-12-01
In this thesis I present the results of a study of the topological structures of 2D U(1) Higgs model and 2D CP N-1 sigma models. Both models have been studied using the overlap Dirac operator construction of topological charge density. The overlap operator provides a more incisive probe into the local topological structure of gauge field configurations than the traditional plaquette-based operator. In the 2D U(1) Higgs model, we show that classical instantons with finite sizes violate the negativity of topological charge correlator by giving a positive contribution to the correlator at non-zero separation. We argue that instantons in 2D U(1) Higgs model must be accompanied by large quantum fluctuations in order to solve this contradiction. In 2D CPN-1 sigma models, we observe the anomalous scaling behavior of the topological susceptibility chi t for N ≤ 3. The divergence of chi t in these models is traced to the presence of small instantons with a radius of order a (= lattice spacing), which are directly observed on the lattice. The observation of these small instantons provides detailed confirmation of Luscher's argument that such short-distance excitations, with quantized topological charge, should be the dominant topological fluctuations in CP1 and CP 2, leading to a divergent topological susceptibility in the continuum limit. For the CPN-1 models with N > 3 the topological susceptibility is observed to scale properly with the mass gap. Another topic presented in this thesis is an implementation of the Zolotarev optimal rational approximation for the overlap Dirac operator. This new implementation has reduced the time complexity of the overlap routine from O(N3 ) to O(N), where N is the total number of sites on the lattice. This opens up a door to more accurate lattice measurements in the future.
Chatterjee, Urmimala; Bose, Partha Pratim; Dey, Sharmistha; Singh, Tej P; Chatterjee, Bishnu P
2008-11-01
T/Tn specificity of Artocarpus lakoocha agglutinin (ALA), isolated from the seeds of A. lakoocha (Moraceae) fruit and a heterodimer (16 kD and 12 kD) of molecular mass 28 kD, was further confirmed by SPR analysis using T/Tn glycan containing mammalian glycoproteins. N-terminal amino acid sequence analysis of ALA showed homology at 15, 19-21, 24-27, and 29 residues with other lectin members of Moraceae family viz., Artocarpus integrifolia (jacalin) lectin, Artocarpus hirsuta lectin, and Maclura pomifera agglutinin. It is mitogenic to human PBMC and the maximum proliferation was observed at 1 ng/ml. It showed an antiproliferative effect on leukemic cells, with the highest effect toward Jurkat cells (IC(50) 13.15 ng/ml). Synthesized CdS quantum dot-ALA nanoconjugate was employed to detect the expression of T/Tn glycans on Jurkat, U937, and K562 leukemic cells surfaces as well as normal lymphocytes by fluorescence microscopy. No green fluorescence was observed with normal lymphocytes indicating that T/Tn determinants, which are recognized as human tumor associated structures were cryptic on normal lymphocyte surfaces, whereas intense green fluorescent dots appeared during imaging of leukemic cells, where such determinants were present in unmasked form. The above results indicated that QD-ALA nanoconjugate is an efficient fluorescent marker for identification of leukemic cell lines that gives rise to high quality images.
Optimizing sparse sampling for 2D electronic spectroscopy
NASA Astrophysics Data System (ADS)
Roeding, Sebastian; Klimovich, Nikita; Brixner, Tobias
2017-02-01
We present a new data acquisition concept using optimized non-uniform sampling and compressed sensing reconstruction in order to substantially decrease the acquisition times in action-based multidimensional electronic spectroscopy. For this we acquire a regularly sampled reference data set at a fixed population time and use a genetic algorithm to optimize a reduced non-uniform sampling pattern. We then apply the optimal sampling for data acquisition at all other population times. Furthermore, we show how to transform two-dimensional (2D) spectra into a joint 4D time-frequency von Neumann representation. This leads to increased sparsity compared to the Fourier domain and to improved reconstruction. We demonstrate this approach by recovering transient dynamics in the 2D spectrum of a cresyl violet sample using just 25% of the originally sampled data points.
D2-D1 phase transition of columnar liquid crystals
NASA Astrophysics Data System (ADS)
Sun, Y. F.; Swift, J.
1986-04-01
The D2-D1 phase transition in columnar liquid crystals of the HAT series [e.g., HAT11 (triphenelene hexa-n-dodecanoate)] is discussed within the framework of Landau theory. The order parameters which describe the transition are abstracted from a tensor density function, and are associated with two irreducible representations of the symmetry group of the high-temperature D2 phase. A mechanism for a first-order transition is then suggested in accordance with both theoretical considerations and the experimental result for the D2-D1 transition. Two possible arrangements of the herringbone structure of the D1 phase are obtained, each of which gives six orientational states in the low-temperature D1 phase.
Extreme Growth of Enstrophy on 2D Bounded Domains
NASA Astrophysics Data System (ADS)
Protas, Bartosz; Sliwiak, Adam
2016-11-01
We study the vortex states responsible for the largest instantaneous growth of enstrophy possible in viscous incompressible flow on 2D bounded domain. The goal is to compare these results with estimates obtained using mathematical analysis. This problem is closely related to analogous questions recently considered in the periodic setting on 1D, 2D and 3D domains. In addition to systematically characterizing the most extreme behavior, these problems are also closely related to the open question of the finite-time singularity formation in the 3D Navier-Stokes system. We demonstrate how such extreme vortex states can be found as solutions of constrained variational optimization problems which in the limit of small enstrophy reduce to eigenvalue problems. Computational results will be presented for circular and square domains emphasizing the effect of geometric singularities (corners of the domain) on the structure of the extreme vortex states. Supported by an NSERC (Canada) Discovery Grant.
Strength design with 2-d triaxial braid textile composites
Smith, L.V.; Swanson, S.R.
1994-12-31
Textile preforms are currently being considered as a possible means for reducing the cost of advanced fiber composites. This paper presents a methodology for strength design of carbon/epoxy 2-d braid fiber composites under general conditions of biaxial stress loading. A comprehensive investigation into the in-plane strength properties of 2-d braids has been carried out, using tubular specimens of AS4/1895 carbon fiber/epoxy made with the RTM process. The biaxial loadings involved both compression-compression and tension-tension biaxial tests. The results showed that failure under biaxial loading could be based on procedures similar to those developed for laminates, using critical strain values in the axial and braid direction fibers, but with degraded strength properties because of the undulating nature of -the fiber paths. A significant loss of strength was observed in the braid directions.
Band-structure engineering in conjugated 2D polymers.
Gutzler, Rico
2016-10-26
Conjugated polymers find widespread application in (opto)electronic devices, sensing, and as catalysts. Their common one-dimensional structure can be extended into the second dimension to create conjugated planar sheets of covalently linked molecules. Extending π-conjugation into the second dimension unlocks a new class of semiconductive polymers which as a consequence of their unique electronic properties can find usability in numerous applications. In this article the theoretical band structures of a set of conjugated 2D polymers are compared and information on the important characteristics band gap and valence/conduction band dispersion is extracted. The great variance in these characteristics within the investigated set suggests 2D polymers as exciting materials in which band-structure engineering can be used to tailor sheet-like organic materials with desired electronic properties.
Enhanced automated platform for 2D characterization of RFID communications
NASA Astrophysics Data System (ADS)
Vuza, Dan Tudor; Vlǎdescu, Marian
2016-12-01
The characterization of the quality of communication between an RFID reader and a transponder at all expected positions of the latter on the reader antenna is of primal importance for the evaluation of performance of an RFID system. Continuing the line of instruments developed for this purpose by the authors, the present work proposes an enhanced version of a previously introduced automated platform for 2D evaluation. By featuring higher performance in terms of mechanical speed, the new version allows to obtain 2D maps of communication with a higher resolution that would have been prohibitive in terms of test duration with the previous version. The list of measurement procedures that can be executed with the platform is now enlarged with additional ones, such as the determination of the variation of the magnetic coupling between transponder and antenna across the antenna surface and the utilization of transponder simulators for evaluation of the quality of communication.
Transition to chaos in an open unforced 2D flow
NASA Technical Reports Server (NTRS)
Pulliam, Thomas H.; Vastano, John A.
1993-01-01
The present numerical study of unsteady, low Reynolds number flow past a 2D airfoil attempts to ascertain the bifurcation sequence leading from simple periodic to complex aperiodic flow with rising Reynolds number, as well as to characterize the degree of chaos present in the aperiodic flow and assess the role of numerics in the modification and control of the observed bifurcation scenario. The ARC2D Navier-Stokes code is used in an unsteady time-accurate mode for most of these computations. The system undergoes a period-doubling bifurcation to chaos as the Reynolds number is increased from 800 to 1600; its chaotic attractors are characterized by estimates of the fractal dimension and partial Liapunov exponent spectra.
Hard and Soft Physics with 2D Materials
NASA Astrophysics Data System (ADS)
McEuen, Paul
With their remarkable structural, thermal, mechanical, optical, chemical, and electronic properties, 2D materials are truly special. For example, a graphene sheet can be made into a high-performance transistor, but it is also the ultimate realization of a thin mechanical sheet. Such sheets, first studied in detail by August Föppl over a hundred years ago, are notoriously complex, since they can bend, buckle, and crumple in a variety of ways. In this talk, I will discuss a number of experiments to probe these unusual materials, from the effects of ripples on the mechanical properties of a graphene sheet, to folding with atomically thin bimorphs, to the electronic properties of bilayer graphene solitons. Finally, I discuss how the Japanese paper art of kirigami (kiru = `to cut', kami = `paper') applied to 2D materials offers a route to mechanical metamaterials and the construction of nanoscale machines.
2-D Magnetohydrodynamic Modeling of A Pulsed Plasma Thruster
NASA Technical Reports Server (NTRS)
Thio, Y. C. Francis; Cassibry, J. T.; Wu, S. T.; Rodgers, Stephen L. (Technical Monitor)
2002-01-01
Experiments are being performed on the NASA Marshall Space Flight Center (MSFC) MK-1 pulsed plasma thruster. Data produced from the experiments provide an opportunity to further understand the plasma dynamics in these thrusters via detailed computational modeling. The detailed and accurate understanding of the plasma dynamics in these devices holds the key towards extending their capabilities in a number of applications, including their applications as high power (greater than 1 MW) thrusters, and their use for producing high-velocity, uniform plasma jets for experimental purposes. For this study, the 2-D MHD modeling code, MACH2, is used to provide detailed interpretation of the experimental data. At the same time, a 0-D physics model of the plasma initial phase is developed to guide our 2-D modeling studies.
FPCAS2D user's guide, version 1.0
NASA Technical Reports Server (NTRS)
Bakhle, Milind A.
1994-01-01
The FPCAS2D computer code has been developed for aeroelastic stability analysis of bladed disks such as those in fans, compressors, turbines, propellers, or propfans. The aerodynamic analysis used in this code is based on the unsteady two-dimensional full potential equation which is solved for a cascade of blades. The structural analysis is based on a two degree-of-freedom rigid typical section model for each blade. Detailed explanations of the aerodynamic analysis, the numerical algorithms, and the aeroelastic analysis are not given in this report. This guide can be used to assist in the preparation of the input data required by the FPCAS2D code. A complete description of the input data is provided in this report. In addition, four test cases, including inputs and outputs, are provided.
Structural Complexity and Phonon Physics in 2D Arsenenes.
Carrete, Jesús; Gallego, Luis J; Mingo, Natalio
2017-03-15
In the quest for stable 2D arsenic phases, four different structures have been recently claimed to be stable. We show that, due to phonon contributions, the relative stability of those structures differs from previous reports and depends crucially on temperature. We also show that one of those four phases is in fact mechanically unstable. Furthermore, our results challenge the common assumption of an inverse correlation between structural complexity and thermal conductivity. Instead, a richer picture emerges from our results, showing how harmonic interactions, anharmonicity, and symmetries all play a role in modulating thermal conduction in arsenenes. More generally, our conclusions highlight how vibrational properties are an essential element to be carefully taken into account in theoretical searches for new 2D materials.
Micro-structural Fluctuations in 2D Dusty Plasma Liquids
I Lin; Huang, Y.-H.; Teng, L.-W.
2007-07-13
We address structural fluctuations in a cold 2D dusty plasma liquid which is self-organized through the strong Coulomb coupling of the negatively charged micro-meter sized dust particles suspending in weakly ionized discharges. The 2D liquids consist of triangular type ordered domains surrounded by defect clusters, which can be reorganized through avalanche type hopping under the interplay of strong Coulomb coupling and thermal fluctuations. The spatio-temporal evolutions of the local bond-orientational order are directly tracked through digital optical microscopy. The power law scaling of the temporal persistence length of fluctuations is obtained for the cold liquid. The measurement of the conditional probability of the persistence lengths of the successive fluctuating cycles suggests certain types of the persistence length combinations are more preferred. The memory of persistence lasts a few fluctuating cycles.
2D FEM Heat Transfer & E&M Field Code
1992-04-02
TOPAZ and TOPAZ2D are two-dimensional implicit finite element computer codes for heat transfer analysis. TOPAZ2D can also be used to solve electrostatic and magnetostatic problems. The programs solve for the steady-state or transient temperature or electrostatic and magnetostatic potential field on two-dimensional planar or axisymmetric geometries. Material properties may be temperature or potential-dependent and either isotropic or orthotropic. A variety of time and temperature-dependent boundary conditions can be specified including temperature, flux, convection, and radiation. By implementing the user subroutine feature, users can model chemical reaction kinetics and allow for any type of functional representation of boundary conditions and internal heat generation. The programs can solve problems of diffuse and specular band radiation in an enclosure coupled with conduction in the material surrounding the enclosure. Additional features include thermal contact resistance across an interface, bulk fluids, phase change, and energy balances.
Absolute state-selected total cross sections for the ion-molecule reactions O + (4S,2D,2P)+H2(D2)
NASA Astrophysics Data System (ADS)
Li, X.; Huang, Y.-L.; Flesch, G. D.; Ng, C. Y.
1997-01-01
Absolute total cross sections for the state-selected reactions of O+(4S,2D,2P)+H2 (D2) have been measured in the center-of-mass collision energy (Ec.m.) range of 0.02-12 eV. The cross sections for OH+ (OD+) from O+(2D)+H2 (D2) are slightly higher than those from O+(4S)+H2 (D2), whereas the OH+ (OD+) cross sections from O+ (2P)+H2 (D2) are ≈40% lower than those from O+(4S)+H2 (D2) and O+ (2D)+H2 (D2). At Ec.m.<0.5 eV, the total cross sections for OH+ (OD+) from O+ (4S)+H2 (D2) and O+(2D)+H2 (D2) are in accord with those predicted by the Langevin-Gioumousis-Stevenson model. Significantly higher cross sections are observed for H+ (D+) and H2+ (D2+) from O+(2D)+H2 (D2) and O+(2P)+H2 (D2), as compared to those from O+(4S)+H2 (D2). The exothermic nature of the O+(2D,2P)+H2 (D2) charge transfer collisions accounts for the high cross sections observed for H2+ (D2+). While the H+ (D+) ions observed in the O+(4S)+H2 (D2) reaction are identified with the H+ (D+)+O+H channel, the H+ (D+) ions from the reactions involving O+(2D) and O+(2P) are associated mostly with the H+ (D+)+OH (OD) channel, the formation of which obeys the spin-conservation rule. The comparison of the sum (σT) of cross sections for OH+ (OD+), H2+ (D2+), and H+ (D+) from O+(4S)+H2 (D2) to those from O+(2D)+H2 (D2) and O+(2P)+H2 (D2) shows that the σTs for O+(4S)+H2 (D2), O+(2D)+H2 (D2), and O+(2P)+H2 (D2) at Ec.m.<0.5 eV are comparable. At Ec.m.>0.5 eV, the σTs for O+(2P)+H2 (D2) are greater than those for O+(2D)+H2 (D2), which in turn are greater than those for O+(4S)+H2 (D2). This observation is attributed to the increase in the number of accessible product channels for reactions involving the excited O+(2D) and O+(2P) reactant ions.
Local Topological Order Inhibits Thermal Stability in 2D
NASA Astrophysics Data System (ADS)
Landon-Cardinal, Olivier; Poulin, David
2013-03-01
We study the robustness of quantum information stored in the degenerate ground space of a local, frustration-free Hamiltonian with commuting terms on a 2D spin lattice. On one hand, a macroscopic energy barrier separating the distinct ground states under local transformations would protect the information from thermal fluctuations. On the other hand, local topological order would shield the ground space from static perturbations. Here we demonstrate that local topological order implies a constant energy barrier, thus inhibiting thermal stability.
Synchronization of semiconductor laser arrays with 2D Bragg structures
NASA Astrophysics Data System (ADS)
Baryshev, V. R.; Ginzburg, N. S.
2016-08-01
A model of a planar semiconductor multi-channel laser is developed. In this model two-dimensional (2D) Bragg mirror structures are used for synchronizing radiation of multiple laser channels. Coupling of longitudinal and transverse waves can be mentioned as the distinguishing feature of these structures. Synchronization of 20 laser channels is demonstrated with a semi-classical approach based on Maxwell-Bloch equations.
Statistical analysis of quiet stance sway in 2-D.
Bakshi, Avijit; DiZio, Paul; Lackner, James R
2014-04-01
Subjects exposed to a rotating environment that perturbs their postural sway show adaptive changes in their voluntary spatially directed postural motion to restore accurate movement paths but do not exhibit any obvious learning during passive stance. We have found, however, that a variable known to characterize the degree of stochasticity in quiet stance can also reveal subtle learning phenomena in passive stance. We extended Chow and Collins (Phys Rev E 52(1):909-912, 1995) one-dimensional pinned-polymer model (PPM) to two dimensions (2-D) and then evaluated the model's ability to make analytical predictions for 2-D quiet stance. To test the model, we tracked center of mass and centers of foot pressures, and compared and contrasted stance sway for the anterior-posterior versus medio-lateral directions before, during, and after exposure to rotation at 10 rpm. Sway of the body during rotation generated Coriolis forces that acted perpendicular to the direction of sway. We found significant adaptive changes for three characteristic features of the mean square displacement (MSD) function: the exponent of the power law defined at short time scales, the proportionality constant of the power law, and the saturation plateau value defined at longer time scales. The exponent of the power law of MSD at a short time scale lies within the bounds predicted by the 2-D PPM. The change in MSD during exposure to rotation also had a power-law exponent in the range predicted by the theoretical model. We discuss the Coriolis force paradigm for studying postural and movement control and the applicability of the PPM model in 2-D for studying postural adaptation.
Flow transitions in a 2D directional solidification model
NASA Technical Reports Server (NTRS)
Larroude, Philippe; Ouazzani, Jalil; Alexander, J. Iwan D.
1992-01-01
Flow transitions in a Two Dimensional (2D) model of crystal growth were examined using the Bridgman-Stockbarger me thod. Using a pseudo-spectral Chebyshev collocation method, the governing equations yield solutions which exhibit a symmetry breaking flow tansition and oscillatory behavior indicative of a Hopf bifurcation at higher values of Ra. The results are discussed from fluid dynamic viewpoint, and broader implications for process models are also addressed.
Vertical heterostructures based on graphene and other 2D materials
Antonova, I. V.
2016-01-15
Recent advances in the fabrication of vertical heterostructures based on graphene and other dielectric and semiconductor single-layer materials, including hexagonal boron nitride and transition-metal dichalcogenides, are reviewed. Significant progress in this field is discussed together with the great prospects for the development of vertical heterostructures for various applications, which are associated, first of all, with reconsideration of the physical principles of the design and operation of device structures based on graphene combined with other 2D materials.
Fully automated 2D-3D registration and verification.
Varnavas, Andreas; Carrell, Tom; Penney, Graeme
2015-12-01
Clinical application of 2D-3D registration technology often requires a significant amount of human interaction during initialisation and result verification. This is one of the main barriers to more widespread clinical use of this technology. We propose novel techniques for automated initial pose estimation of the 3D data and verification of the registration result, and show how these techniques can be combined to enable fully automated 2D-3D registration, particularly in the case of a vertebra based system. The initialisation method is based on preoperative computation of 2D templates over a wide range of 3D poses. These templates are used to apply the Generalised Hough Transform to the intraoperative 2D image and the sought 3D pose is selected with the combined use of the generated accumulator arrays and a Gradient Difference Similarity Measure. On the verification side, two algorithms are proposed: one using normalised features based on the similarity value and the other based on the pose agreement between multiple vertebra based registrations. The proposed methods are employed here for CT to fluoroscopy registration and are trained and tested with data from 31 clinical procedures with 417 low dose, i.e. low quality, high noise interventional fluoroscopy images. When similarity value based verification is used, the fully automated system achieves a 95.73% correct registration rate, whereas a no registration result is produced for the remaining 4.27% of cases (i.e. incorrect registration rate is 0%). The system also automatically detects input images outside its operating range.
Report of the 1988 2-D Intercomparison Workshop, chapter 3
NASA Technical Reports Server (NTRS)
Jackman, Charles H.; Brasseur, Guy; Soloman, Susan; Guthrie, Paul D.; Garcia, Rolando; Yung, Yuk L.; Gray, Lesley J.; Tung, K. K.; Ko, Malcolm K. W.; Isaken, Ivar
1989-01-01
Several factors contribute to the errors encountered. With the exception of the line-by-line model, all of the models employ simplifying assumptions that place fundamental limits on their accuracy and range of validity. For example, all 2-D modeling groups use the diffusivity factor approximation. This approximation produces little error in tropospheric H2O and CO2 cooling rates, but can produce significant errors in CO2 and O3 cooling rates at the stratopause. All models suffer from fundamental uncertainties in shapes and strengths of spectral lines. Thermal flux algorithms being used in 2-D tracer tranport models produce cooling rates that differ by as much as 40 percent for the same input model atmosphere. Disagreements of this magnitude are important since the thermal cooling rates must be subtracted from the almost-equal solar heating rates to derive the net radiative heating rates and the 2-D model diabatic circulation. For much of the annual cycle, the net radiative heating rates are comparable in magnitude to the cooling rate differences described. Many of the models underestimate the cooling rates in the middle and lower stratosphere. The consequences of these errors for the net heating rates and the diabatic circulation will depend on their meridional structure, which was not tested here. Other models underestimate the cooling near 1 mbar. Suchs errors pose potential problems for future interactive ozone assessment studies, since they could produce artificially-high temperatures and increased O3 destruction at these levels. These concerns suggest that a great deal of work is needed to improve the performance of thermal cooling rate algorithms used in the 2-D tracer transport models.
2D Hybrid Nanostructured Dirac Materials for Broadband Transparent Electrodes.
Guo, Yunfan; Lin, Li; Zhao, Shuli; Deng, Bing; Chen, Hongliang; Ma, Bangjun; Wu, Jinxiong; Yin, Jianbo; Liu, Zhongfan; Peng, Hailin
2015-08-05
Broadband transparent electrodes based on 2D hybrid nanostructured Dirac materials between Bi2 Se3 and graphene are synthesized using a chemical vapor deposition (CVD) method. Bi2 Se3 nanoplates are preferentially grown along graphene grain boundaries as "smart" conductive patches to bridge the graphene boundary. These hybrid films increase by one- to threefold in conductivity while remaining highly transparent over broadband wavelength. They also display outstanding chemical stability and mechanical flexibility.
Parallel-pipeline 2-D DCT/IDCT processor chip
NASA Astrophysics Data System (ADS)
Ruiz, G. A.; Michell, J. A.; Buron, A.
2005-06-01
This paper describes the architecture of an 8x8 2-D DCT/IDCT processor with high throughput and a cost-effective architecture. The 2D DCT/IDCT is calculated using the separability property, so that its architecture is made up of two 1-D processors and a transpose buffer (TB) as intermediate memory. This transpose buffer presents a regular structure based on D-type flip-flops with a double serial input/output data-flow very adequate for pipeline architectures. The processor has been designed with parallel and pipeline architecture to attain high throughput, reduced hardware and maximum efficiency in all arithmetic elements. This architecture allows that the processing elements and arithmetic units work in parallel at half the frequency of the data input rate, except for normalization of transform which it is done in a multiplier operating at maximum frequency. Moreover, it has been verified that the precision analysis of the proposed processor meets the demands of IEEE Std. 1180-1990 used in video codecs ITU-T H.261 and ITU-T H.263. This processor has been conceived using a standard cell design methodology and manufactured in a 0.35-μm CMOS CSD 3M/2P 3.3V process. It has an area of 6.25 mm2 (the core is 3mm2) and contains a total of 11.7k gates, of which 5.8k gates are flip-flops. A data input rate frequency of 300MHz has been established with a latency of 172 cycles for the 2-D DCT and 178 cycles for the 2-D IDCT. The computing time of a block is close to 580ns. Its performances in computing speed as well as hardware complexity indicate that the proposed design is suitable for HDTV applications.
FASTWO - A 2-D interactive algebraic grid generator
NASA Technical Reports Server (NTRS)
Luh, Raymond Ching-Chung; Lombard, C. K.
1988-01-01
This paper presents a very simple and effective computational procedure, FASTWO, for generating patched composite finite difference grids in 2-D for any geometry. Major components of the interactive graphics based method that is closely akin to and borrows many tools from transfinite interpolation are highlighted. Several grids produced by FASTWO are shown to illustrate its powerful capability. Comments about extending the methodology to 3-D are also given.
Energy level transitions of gas in a 2D nanopore
Grinyaev, Yurii V.; Chertova, Nadezhda V.; Psakhie, Sergei G.
2015-10-27
An analytical study of gas behavior in a 2D nanopore was performed. It is shown that the temperature dependence of gas energy can be stepwise due to transitions from one size-quantized subband to another. Taking into account quantum size effects results in energy level transitions governed by the nanopore size, temperature and gas density. This effect leads to an abrupt change of gas heat capacity in the nanopore at the above varying system parameters.
2D Lattices of Ferromagnetic Nanoparticles as Supermagnetics
1999-06-18
Supermagnetics DISTRIBUTION: Approved for public release, distribution unlimited Availability: Hard copy only. This paper is part of the following report: TITLE...Technology" OAN.01 i St Petersburg, Russia, June 14-18, 1999 © 1999 loffe Institute 2D lattices of ferromagnetic nanoparticles as supermagnetics A. A...temperature the system became ordered due to the dipole interaction of particles. Such a state of the system was defined as supermagnetic [ ]. The critical
2D and 3D Traveling Salesman Problem
ERIC Educational Resources Information Center
Haxhimusa, Yll; Carpenter, Edward; Catrambone, Joseph; Foldes, David; Stefanov, Emil; Arns, Laura; Pizlo, Zygmunt
2011-01-01
When a two-dimensional (2D) traveling salesman problem (TSP) is presented on a computer screen, human subjects can produce near-optimal tours in linear time. In this study we tested human performance on a real and virtual floor, as well as in a three-dimensional (3D) virtual space. Human performance on the real floor is as good as that on a…
Numerical 2D-modeling of multiroll leveling
NASA Astrophysics Data System (ADS)
Mathieu, N.; Potier-Ferry, M.; Zahrouni, H.
2016-10-01
Multiroll leveling is a forming process used in the metals industries (aluminum, steel, …) in order to correct flatness defects and minimize residual stresses in strips thanks to alternating bending. This work proposes a Finite Element 2D model to simulate the metal sheet conveying through the machine. Obtained results (plastic strain and residual stress distributions through thickness) are analysed. Strip deformation, after elastic springback and potential buckling, is also predicted (residual curvatures).
2-D Signal Generation Using State-Space Formulation.
1985-12-01
published that have established nonoptical .~ -~ Iimage processing as a viable area of research. A large portion of this research emphasizes the linear...research and the study of time-discrete linear systems. This thesis develops the discrete model of Roesser [Ref. 5] for linear image processing which... THESIS 2-D SIGNAL GENERATION USING STATE-SPACE FORMULATION - • by (.) Evangelos Theofilou December 1985 • Thesis Advisor: Sydney R. Parker Approved
Geometric properties of quasiperiodic orbits of 2D Hamiltonian systems
NASA Astrophysics Data System (ADS)
Adrover, A.; Giona, M.
1999-08-01
By enforcing the isomorphism between the group SL(2, R ) and linear fractional transforms, this letter shows that, for quasi-periodic orbits of 2D area-preserving maps possessing regions of chaotic behavior, the vector tangent to the quasiperiodic orbit can be obtained from the dynamics of the associated linear fractional transforms (obtained from the differential of the map), which is Cesaro convergent. Several implications of this geometric result are addressed.
[3D display of sequential 2D medical images].
Lu, Yisong; Chen, Yazhu
2003-12-01
A detailed review is given in this paper on various current 3D display methods for sequential 2D medical images and the new development in 3D medical image display. True 3D display, surface rendering, volume rendering, 3D texture mapping and distributed collaborative rendering are discussed in depth. For two kinds of medical applications: Real-time navigation system and high-fidelity diagnosis in computer aided surgery, different 3D display methods are presented.
NASA High-Speed 2D Photogrammetric Measurement System
NASA Technical Reports Server (NTRS)
Dismond, Harriett R.
2012-01-01
The object of this report is to provide users of the NASA high-speed 2D photogrammetric measurement system with procedures required to obtain drop-model trajectory and impact data for full-scale and sub-scale models. This guide focuses on use of the system for vertical drop testing at the NASA Langley Landing and Impact Research (LandIR) Facility.
2D:4D Ratio and its Implications in Medicine
Jeevanandam, Saravanakumar
2016-01-01
Digit ratios, especially 2D:4D ratio, a potential proxy marker for prenatal androgen exposure shows sexual dimorphism. Existing literature and recent research show accumulating evidence on 2D:4D ratio showing correlations with various phenotypic traits in humans. Ratio of 2D:4D is found to correlate negatively to testosterone and positively to oestrogen in the foetus. Interestingly, it is constant since birth and not influenced by the adult hormone levels. Usually, males have lower ratios when compared to females. Prenatal androgen exposure and therefore, digit ratios have been reported to be associated with numerical competencies, spatial skills, handedness, cognitive abilities, academic performance, sperm counts, personalities and prevalence of obesity, migraine, eating disorders, depression, myopia, autism etc. The authors have attempted to write a brief account on the digit ratios and the dimorphism observed in various physiological, psychological and behavioural traits. Also, the authors have discussed the relevant molecular basics and the methods of measurement of digit ratios. PMID:28208851
2D optical beam splitter using diffractive optical elements (DOE)
NASA Astrophysics Data System (ADS)
Wen, Fung J.; Chung, Po S.
2006-09-01
A novel approach for optical beam distribution into a 2-dimensional (2-D) packaged fiber arrays using 2-D Dammann gratings is investigated. This paper focuses on the design and fabrication of the diffractive optical element (DOE) and investigates the coupling efficiencies of the beamlets into a packaged V-grooved 2x2 fibre array. We report for the first time experimental results of a 2-D optical signal distribution into a packaged 2x2 fibre array using Dammann grating. This grating may be applicable to the FTTH network as it can support sufficient channels with good output uniformity together with low polarization dependent loss (PDL) and acceptable insertion loss. Using an appropriate optimization algorithm (the steepest descent algorithm in this case), the optimum profile for the gratings can be calculated. The gratings are then fabricated on ITO glass using electron-beam lithography. The overall performance of the design shows an output uniformity of around 0.14 dB and an insertion loss of about 12.63 dB, including the DOE, focusing lens and the packaged fiber array.
Shear viscosity measurements in a 2D Yukawa liquid
NASA Astrophysics Data System (ADS)
Nosenko, Volodymyr
2005-03-01
Shear viscosity was measured for a 2D strongly-coupled Yukawa liquid. First, we formed a dilute monolayer suspension of microspheres in a partially-ionized rarefied gas, i.e., a dusty plasma. In the absence of manipulation, the suspension forms a 2D triangular lattice. We used a new in-situ method of applying a shear stress using the scattering forces applied by counter-propagating laser beams. The lattice melted and a shear flow formed. Using digital video microscopy for direct imaging and particle tracking, the microscopic dynamics of the shear flow are observed. Averaging the velocities of individual microspheres, a velocity flow profile was calculated. Using the Navier-Stokes equation with an additional frictional term to account for gas drag, we fit the velocity profile. The fit yielded the value of the shear viscosity. The kinematic viscosity of our particle suspension is of order 1 mm^2s-1, which is comparable to that for liquid water. We believe this is the first report of a rheological measurement in a 2D dusty plasma. This talk is based on V. Nosenko and J. Goree, PRL 93, 155004 (2004).
Hybrid 3D-2D printing for bone scaffolds fabrication
NASA Astrophysics Data System (ADS)
Seleznev, V. A.; Prinz, V. Ya
2017-02-01
It is a well-known fact that bone scaffold topography on micro- and nanometer scale influences the cellular behavior. Nano-scale surface modification of scaffolds allows the modulation of biological activity for enhanced cell differentiation. To date, there has been only a limited success in printing scaffolds with micro- and nano-scale features exposed on the surface. To improve on the currently available imperfect technologies, in our paper we introduce new hybrid technologies based on a combination of 2D (nano imprint) and 3D printing methods. The first method is based on using light projection 3D printing and simultaneous 2D nanostructuring of each of the layers during the formation of the 3D structure. The second method is based on the sequential integration of preliminarily created 2D nanostructured films into a 3D printed structure. The capabilities of the developed hybrid technologies are demonstrated with the example of forming 3D bone scaffolds. The proposed technologies can be used to fabricate complex 3D micro- and nanostructured products for various fields.
Volumetric elasticity imaging with a 2-D CMUT array.
Fisher, Ted G; Hall, Timothy J; Panda, Satchi; Richards, Michael S; Barbone, Paul E; Jiang, Jingfeng; Resnick, Jeff; Barnes, Steve
2010-06-01
This article reports the use of a two-dimensional (2-D) capacitive micro-machined ultrasound transducer (CMUT) to acquire radio-frequency (RF) echo data from relatively large volumes of a simple ultrasound phantom to compare three-dimensional (3-D) elasticity imaging methods. Typical 2-D motion tracking for elasticity image formation was compared with three different methods of 3-D motion tracking, with sum-squared difference (SSD) used as the similarity measure. Differences among the algorithms were the degree to which they tracked elevational motion: not at all (2-D search), planar search, combination of multiple planes and plane independent guided search. The cross-correlation between the predeformation and motion-compensated postdeformation RF echo fields was used to quantify motion tracking accuracy. The lesion contrast-to-noise ratio was used to quantify image quality. Tracking accuracy and strain image quality generally improved with increased tracking sophistication. When used as input for a 3-D modulus reconstruction, high quality 3-D displacement estimates yielded accurate and low noise modulus reconstruction.
Building 3D scenes from 2D image sequences
NASA Astrophysics Data System (ADS)
Cristea, Paul D.
2006-05-01
Sequences of 2D images, taken by a single moving video receptor, can be fused to generate a 3D representation. This dynamic stereopsis exists in birds and reptiles, whereas the static binocular stereopsis is common in mammals, including humans. Most multimedia computer vision systems for stereo image capture, transmission, processing, storage and retrieval are based on the concept of binocularity. As a consequence, their main goal is to acquire, conserve and enhance pairs of 2D images able to generate a 3D visual perception in a human observer. Stereo vision in birds is based on the fusion of images captured by each eye, with previously acquired and memorized images from the same eye. The process goes on simultaneously and conjointly for both eyes and generates an almost complete all-around visual field. As a consequence, the baseline distance is no longer fixed, as in the case of binocular 3D view, but adjustable in accordance with the distance to the object of main interest, allowing a controllable depth effect. Moreover, the synthesized 3D scene can have a better resolution than each individual 2D image in the sequence. Compression of 3D scenes can be achieved, and stereo transmissions with lower bandwidth requirements can be developed.
A novel point cloud registration using 2D image features
NASA Astrophysics Data System (ADS)
Lin, Chien-Chou; Tai, Yen-Chou; Lee, Jhong-Jin; Chen, Yong-Sheng
2017-01-01
Since a 3D scanner only captures a scene of a 3D object at a time, a 3D registration for multi-scene is the key issue of 3D modeling. This paper presents a novel and an efficient 3D registration method based on 2D local feature matching. The proposed method transforms the point clouds into 2D bearing angle images and then uses the 2D feature based matching method, SURF, to find matching pixel pairs between two images. The corresponding points of 3D point clouds can be obtained by those pixel pairs. Since the corresponding pairs are sorted by their distance between matching features, only the top half of the corresponding pairs are used to find the optimal rotation matrix by the least squares approximation. In this paper, the optimal rotation matrix is derived by orthogonal Procrustes method (SVD-based approach). Therefore, the 3D model of an object can be reconstructed by aligning those point clouds with the optimal transformation matrix. Experimental results show that the accuracy of the proposed method is close to the ICP, but the computation cost is reduced significantly. The performance is six times faster than the generalized-ICP algorithm. Furthermore, while the ICP requires high alignment similarity of two scenes, the proposed method is robust to a larger difference of viewing angle.
Resolving 2D Amorphous Materials with Scanning Probe Microscopy
NASA Astrophysics Data System (ADS)
Burson, Kristen M.; Buechner, Christin; Lewandowski, Adrian; Heyde, Markus; Freund, Hans-Joachim
Novel two-dimensional (2D) materials have garnered significant scientific interest due to their potential technological applications. Alongside the emphasis on crystalline materials, such as graphene and hexagonal BN, a new class of 2D amorphous materials must be pursued. For amorphous materials, a detailed understanding of the complex structure is necessary. Here we present a structural study of 2D bilayer silica on Ru(0001), an insulating material which is weakly coupled to the substrate. Atomic structure has been determined with a dual mode atomic force microscopy (AFM) and scanning tunneling microscopy (STM) sensor in ultra-high vacuum (UHV) at low temperatures, revealing a network of different ring sizes. Liquid AFM measurements with sub-nanometer resolution bridge the gap between clean UHV conditions and the environments that many material applications demand. Samples are grown and characterized in vacuum and subsequently transferred to the liquid AFM. Notably, the key structural features observed, namely nanoscale ring networks and larger holes to the substrate, show strong quantitative agreement between the liquid and UHV microscopy measurements. This provides direct evidence for the structural stability of these silica films for nanoelectronics and other applications. KMB acknowledges support from the Alexander von Humboldt Foundation.
F-theory and 2d (0, 2) theories
NASA Astrophysics Data System (ADS)
Schäfer-Nameki, Sakura; Weigand, Timo
2016-05-01
F-theory compactified on singular, elliptically fibered Calabi-Yau five-folds gives rise to two-dimensional gauge theories preserving N = (0 , 2) supersymmetry. In this paper we initiate the study of such compactifications and determine the dictionary between the geometric data of the elliptic fibration and the 2d gauge theory such as the matter content in terms of (0 , 2) superfields and their supersymmetric couplings. We study this setup both from a gauge-theoretic point of view, in terms of the partially twisted 7-brane theory, and provide a global geometric description based on the structure of the elliptic fibration and its singularities. Global consistency conditions are determined and checked against the dual M-theory compactification to one dimension. This includes a discussion of gauge anomalies, the structure of the Green-Schwarz terms and the Chern-Simons couplings in the dual M-theory supersymmetric quantum mechanics. Furthermore, by interpreting the resulting 2d (0 , 2) theories as heterotic worldsheet theories, we propose a correspondence between the geometric data of elliptically fibered Calabi-Yau five-folds and the target space of a heterotic gauged linear sigma-model (GLSM). In particular the correspondence between the Landau-Ginsburg and sigma-model phase of a 2d (0 , 2) GLSM is realized via different T-branes or gluing data in F-theory.
An Intercomparison of 2-D Models Within a Common Framework
NASA Technical Reports Server (NTRS)
Weisenstein, Debra K.; Ko, Malcolm K. W.; Scott, Courtney J.; Jackman, Charles H.; Fleming, Eric L.; Considine, David B.; Kinnison, Douglas E.; Connell, Peter S.; Rotman, Douglas A.; Bhartia, P. K. (Technical Monitor)
2002-01-01
A model intercomparison among the Atmospheric and Environmental Research (AER) 2-D model, the Goddard Space Flight Center (GSFC) 2-D model, and the Lawrence Livermore National Laboratory 2-D model allows us to separate differences due to model transport from those due to the model's chemical formulation. This is accomplished by constructing two hybrid models incorporating the transport parameters of the GSFC and LLNL models within the AER model framework. By comparing the results from the native models (AER and e.g. GSFC) with those from the hybrid model (e.g. AER chemistry with GSFC transport), differences due to chemistry and transport can be identified. For the analysis, we examined an inert tracer whose emission pattern is based on emission from a High Speed Civil Transport (HSCT) fleet; distributions of trace species in the 2015 atmosphere; and the response of stratospheric ozone to an HSCT fleet. Differences in NO(y) in the upper stratosphere are found between models with identical transport, implying different model representations of atmospheric chemical processes. The response of O3 concentration to HSCT aircraft emissions differs in the models from both transport-dominated differences in the HSCT-induced perturbations of H2O and NO(y) as well as from differences in the model represent at ions of O3 chemical processes. The model formulations of cold polar processes are found to be the most significant factor in creating large differences in the calculated ozone perturbations
Volumetric Elasticity Imaging with a 2D CMUT Array
Fisher, Ted G.; Hall, Timothy J.; Panda, Satchi; Richards, Michael S.; Barbone, Paul E.; Jiang, Jingfeng; Resnick, Jeff; Barnes, Steve
2010-01-01
This paper reports the use of a two-dimensional (2D) capacitive micro-machined ultrasound transducer (CMUT) to acquire radio frequency (RF) echo data from relatively large volumes of a simple ultrasound phantom to compare 3D elasticity imaging methods. Typical 2D motion tracking for elasticity image formation was compared to three different methods of 3D motion tracking, with sum-squared difference (SSD) used as the similarity measure. Differences among the algorithms were the degree to which they tracked elevational motion: not at all (2D search), planar search, combination of multiple planes, and plane independent guided search. The cross correlation between the pre-deformation and motion-compensated post-deformation RF echo fields was used to quantify motion tracking accuracy. The lesion contrast-to-noise ratio was used to quantify image quality. Tracking accuracy and strain image quality generally improved with increased tracking sophistication. When used as input for a 3D modulus reconstruction, high quality 3D displacement estimates yielded accurate and low noise modulus reconstruction. PMID:20510188
Murine cytomegalovirus regulation of NKG2D ligands.
Lenac, Tihana; Arapović, Jurica; Traven, Luka; Krmpotić, Astrid; Jonjić, Stipan
2008-06-01
Human cytomegalovirus (HCMV) is a ubiquitous pathogen that causes morbidity risk in immunologically suppressed and immunodeficient patients including congenital infections. Approaches to curb the consequences of HCMV infections are restricted by a lack of complete understanding of viral pathogenesis. The infection of mice with murine cytomegalovirus (MCMV) as a model of HCMV infection has been particularly useful in elucidating the role of innate and adaptive immune response mechanisms. A large number of cytomegalovirus genes modulate the innate and the adaptive host immune response. The products of several MCMV genes are involved in subverting the natural killer (NK) cell response by down-modulating cellular ligands for the NKG2D receptor expressed on NK cells and CD8(+) T cells. Mutant viruses lacking these immunoevasion genes are attenuated with respect to virus growth in vivo. Given the importance of the NKG2D receptor in controlling both NK- and T cell-mediated immunity, it is of tremendous importance to understand the molecular mechanisms and consequences of viral regulation of the NKG2D ligands.
Design Application Translates 2-D Graphics to 3-D Surfaces
NASA Technical Reports Server (NTRS)
2007-01-01
Fabric Images Inc., specializing in the printing and manufacturing of fabric tension architecture for the retail, museum, and exhibit/tradeshow communities, designed software to translate 2-D graphics for 3-D surfaces prior to print production. Fabric Images' fabric-flattening design process models a 3-D surface based on computer-aided design (CAD) specifications. The surface geometry of the model is used to form a 2-D template, similar to a flattening process developed by NASA's Glenn Research Center. This template or pattern is then applied in the development of a 2-D graphic layout. Benefits of this process include 11.5 percent time savings per project, less material wasted, and the ability to improve upon graphic techniques and offer new design services. Partners include Exhibitgroup/Giltspur (end-user client: TAC Air, a division of Truman Arnold Companies Inc.), Jack Morton Worldwide (end-user client: Nickelodeon), as well as 3D Exhibits Inc., and MG Design Associates Corp.
2D depiction of nonbonding interactions for protein complexes.
Zhou, Peng; Tian, Feifei; Shang, Zhicai
2009-04-30
A program called the 2D-GraLab is described for automatically generating schematic representation of nonbonding interactions across the protein binding interfaces. The input file of this program takes the standard PDB format, and the outputs are two-dimensional PostScript diagrams giving intuitive and informative description of the protein-protein interactions and their energetics properties, including hydrogen bond, salt bridge, van der Waals interaction, hydrophobic contact, pi-pi stacking, disulfide bond, desolvation effect, and loss of conformational entropy. To ensure these interaction information are determined accurately and reliably, methods and standalone programs employed in the 2D-GraLab are all widely used in the chemistry and biology community. The generated diagrams allow intuitive visualization of the interaction mode and binding specificity between two subunits in protein complexes, and by providing information on nonbonding energetics and geometric characteristics, the program offers the possibility of comparing different protein binding profiles in a detailed, objective, and quantitative manner. We expect that this 2D molecular graphics tool could be useful for the experimentalists and theoreticians interested in protein structure and protein engineering.
Broadband THz Spectroscopy of 2D Nanoscale Materials
NASA Astrophysics Data System (ADS)
Chen, Lu; Tripathi, Shivendra; Huang, Mengchen; Hsu, Jen-Feng; D'Urso, Brian; Lee, Hyungwoo; Eom, Chang-Beom; Irvin, Patrick; Levy, Jeremy
Two-dimensional (2D) materials such as graphene and transition-metal dichalcogenides (TMDC) have attracted intense research interest in the past decade. Their unique electronic and optical properties offer the promise of novel optoelectronic applications in the terahertz regime. Recently, generation and detection of broadband terahertz (10 THz bandwidth) emission from 10-nm-scale LaAlO3/SrTiO3 nanostructures created by conductive atomic force microscope (c-AFM) lithography has been demonstrated . This unprecedented control of THz emission at 10 nm length scales creates a pathway toward hybrid THz functionality in 2D-material/LaAlO3/SrTiO3 heterostructures. Here we report initial efforts in THz spectroscopy of 2D nanoscale materials with resolution comparable to the dimensions of the nanowire (10 nm). Systems under investigation include graphene, single-layer molybdenum disulfide (MoS2), and tungsten diselenide (WSe2) nanoflakes. 1. Y. Ma, et al., Nano Lett. 13, 2884 (2013). We gratefully acknowledge financial support from the following agencies and grants: AFOSR (FA9550-12-1-0268 (JL, PRI), FA9550-12-1-0342 (CBE)), ONR (N00014-13-1-0806 (JL, CBE), N00014-15-1-2847 (JL)), NSF DMR-1124131 (JL, CBE) and DMR-1234096 (CBE).
Cytochrome P450-2D6 Screening Among Elderly Using Antidepressants (CYSCE)
2016-10-24
Depression; Depressive Disorder; Poor Metabolizer Due to Cytochrome P450 CYP2D6 Variant; Intermediate Metabolizer Due to Cytochrome P450 CYP2D6 Variant; Ultrarapid Metabolizer Due to Cytochrome P450 CYP2D6 Variant
Analysis of the antiferromagnetic phase transitions of the 2D Kondo lattice
NASA Astrophysics Data System (ADS)
Jones, Barbara
2010-03-01
The Kondo lattice continues to present an interesting and relevant challenge, with its interactions between Kondo, RKKY, and coherent order. We present our study[1] of the antiferromagnetic quantum phase transitions of a 2D Kondo-Heisenberg square lattice. Starting from the nonlinear sigma model as a model of antiferromagnetism, we carry out a renormalization group analysis of the competing Kondo-RKKY interaction to one-loop order in an ɛ-expansion. We find a new quantum critical point (QCP) strongly affected by Kondo fluctuations. Near this QCP, there is a breakdown of hydrodynamic behavior, and the spin waves are logarithmically frozen out. The renormalization group results allow us to propose a new phase diagram near the antiferromagnetic fixed point of this 2D Kondo lattice model. The T=0 phase diagram contains four phases separated by a tetracritical point, the new QCP. For small spin fluctuations, we find a stable local magnetic moment antiferromagnet. For stronger coupling, region II is a metallic quantum disordered paramagnet. We find in region III a paramagnetic phase driven by Kondo interactions, with possible ground states of a heavy fermion liquid or a Kondo driven spin-liquid. The fourth phase is a spiral phase, or a large-Fermi-surface antiferromagnetic phase. We will describe these phases in more detail, including possible experimental confirmation of the spiral phase. The existence of the tetracritical point found here would be expected to affect the phase diagram at finite temperatures as well. In addition, It is hoped that these results, and particularly the Kondo interaction paramagnetic phase, will serve to bridge to solutions starting from the opposite limit, of a Kondo effect leading to a heavy fermion ground state. Work in collaboration with T. Tzen Ong. [4pt] [1] T. Ong and B. A. Jones, Phys. Rev. Lett. 103, 066405 (2009).
Disentangling Redshift-Space Distortions and Nonlinear Bias using the 2D Power Spectrum
Jennings, Elise; Wechsler, Risa H.
2015-08-07
We present the nonlinear 2D galaxy power spectrum, P(k, µ), in redshift space, measured from the Dark Sky simulations, using galaxy catalogs constructed with both halo occupation distribution and subhalo abundance matching methods, chosen to represent an intermediate redshift sample of luminous red galaxies. We find that the information content in individual µ (cosine of the angle to the line of sight) bins is substantially richer then multipole moments, and show that this can be used to isolate the impact of nonlinear growth and redshift space distortion (RSD) effects. Using the µ < 0.2 simulation data, which we show is not impacted by RSD effects, we can successfully measure the nonlinear bias to an accuracy of ~ 5% at k < 0.6hMpc-1 . This use of individual µ bins to extract the nonlinear bias successfully removes a large parameter degeneracy when constraining the linear growth rate of structure. We carry out a joint parameter estimation, using the low µ simulation data to constrain the nonlinear bias, and µ > 0.2 to constrain the growth rate and show that f can be constrained to ~ 26(22)% to a kmax < 0.4(0.6)hMpc-1 from clustering alone using a simple dispersion model, for a range of galaxy models. Our analysis of individual µ bins also reveals interesting physical effects which arise simply from different methods of populating halos with galaxies. We also find a prominent turnaround scale, at which RSD damping effects are greater then the nonlinear growth, which differs not only for each µ bin but also for each galaxy model. These features may provide unique signatures which could be used to shed light on the galaxy–dark matter connection. Furthermore, the idea of separating nonlinear growth and RSD effects making use of the full information in the 2D galaxy power spectrum yields significant improvements in constraining cosmological parameters and may be a promising probe of galaxy formation models.
A Method to Calculate Protein Dipole Moments
NASA Astrophysics Data System (ADS)
Mellor, Brett; Mazzeo, Brian
2009-10-01
The electric dipole moments of globular proteins, determined experimentally by dielectric relaxation spectroscopy, contribute to both protein function and structure. Numerical computations of dipole moments can be obtained from structures in the Protein Data Bank. However, previous computations in literature have agreed with experimental results for only a limited number of proteins. This paper presents a method to compute the pH-dependent dipole moment. The protein molecule is considered as an array of electrical point charges in aqueous solution. The dipole moment is calculated as the vector sum of two components: (1)the core dipole moment which emerges from the unequal sharing of electrons in covalent bonds; (2)the surface charge dipole moment resulting from pH-dependent side chain partial charges. pKa shifts for each side chain amino acid are determined by the H++ server employing the Poisson-Boltzmann equation. The net charge and dipole moment over a range of pH are calculated. The Oncley equation is used to predict the dielectric increment at arbitrary pH, temperature, and protein concentration.
Table of nuclear electric quadrupole moments
NASA Astrophysics Data System (ADS)
Stone, N. J.
2016-09-01
This Table is a compilation of experimental measurements of static electric quadrupole moments of ground states and excited states of atomic nuclei throughout the periodic table. To aid identification of the states, their excitation energy, half-life, spin and parity are given, along with a brief indication of the method and any reference standard used in the particular measurement. Experimental data from all quadrupole moment measurements actually provide a value of the product of the moment and the electric field gradient [EFG] acting at the nucleus. Knowledge of the EFG is thus necessary to extract the quadrupole moment. A single recommended moment value is given for each state, based, for each element, wherever possible, upon a standard reference moment for a nuclear state of that element studied in a situation in which the electric field gradient has been well calculated. For several elements one or more subsidiary EFG/moment reference is required and their use is specified. The literature search covers the period to mid-2015.
Detecting neutrino magnetic moments with conducting loops
NASA Astrophysics Data System (ADS)
Apyan, Aram; Apyan, Armen; Schmitt, Michael
2008-02-01
It is well established that neutrinos have mass, yet it is very difficult to measure those masses directly. Within the standard model of particle physics, neutrinos will have an intrinsic magnetic moment proportional to their mass. We examine the possibility of detecting the magnetic moment using a conducting loop. According to Faraday’s law of induction, a magnetic dipole passing through a conducting loop induces an electromotive force in the loop. We compute this electromotive force for neutrinos in several cases, based on a fully covariant formulation of the problem. We discuss prospects for a real experiment, as well as the possibility to test the relativistic formulation of intrinsic magnetic moments.
The Gulf Moment: Arab Relations Since 2011
2015-05-01
THE GULF MOMENT: ARAB RElATIONS SINCE 201 t Florence Gaub UNITED STATES ARMY WAR COLLEGE PRESS CarlisleBarracks,PA .., STRENGTH-’WISDOM U.S...SUBTITLE The Gulf Moment: Arab Relations Since 2011 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e...Institute and U.S. Army War College Press THE GULF MOMENT: ARAB RELATIONS SINCE 2011 Florence Gaub May 2015 The views expressed in this report are
Koh, Kwi Hye; Pan, Xian; Shen, Hong-Wu; Arnold, Samuel L M; Yu, Ai-Ming; Gonzalez, Frank J; Isoherranen, Nina; Jeong, Hyunyoung
2014-02-07
Substrates of a major drug-metabolizing enzyme CYP2D6 display increased elimination during pregnancy, but the underlying mechanisms are unknown in part due to a lack of experimental models. Here, we introduce CYP2D6-humanized (Tg-CYP2D6) mice as an animal model where hepatic CYP2D6 expression is increased during pregnancy. In the mouse livers, expression of a known positive regulator of CYP2D6, hepatocyte nuclear factor 4α (HNF4α), did not change during pregnancy. However, HNF4α recruitment to CYP2D6 promoter increased at term pregnancy, accompanied by repressed expression of small heterodimer partner (SHP). In HepG2 cells, SHP repressed HNF4α transactivation of CYP2D6 promoter. In transgenic (Tg)-CYP2D6 mice, SHP knockdown led to a significant increase in CYP2D6 expression. Retinoic acid, an endogenous compound that induces SHP, exhibited decreased hepatic levels during pregnancy in Tg-CYP2D6 mice. Administration of all-trans-retinoic acid led to a significant decrease in the expression and activity of hepatic CYP2D6 in Tg-CYP2D6 mice. This study provides key insights into mechanisms underlying altered CYP2D6-mediated drug metabolism during pregnancy, laying a foundation for improved drug therapy in pregnant women.
Garaud, Pascale; Brummell, Nicholas
2015-12-10
Fingering convection (otherwise known as thermohaline convection) is an instability that occurs in stellar radiative interiors in the presence of unstable compositional gradients. Numerical simulations have been used in order to estimate the efficiency of mixing induced by this instability. However, fully three-dimensional (3D) computations in the parameter regime appropriate for stellar astrophysics (i.e., low Prandtl number) are prohibitively expensive. This raises the question of whether two-dimensional (2D) simulations could be used instead to achieve the same goals. In this work, we address this issue by comparing the outcome of 2D and 3D simulations of fingering convection at low Prandtl number. We find that 2D simulations are never appropriate. However, we also find that the required 3D computational domain does not have to be very wide: the third dimension only needs to contain a minimum of two wavelengths of the fastest-growing linearly unstable mode to capture the essentially 3D dynamics of small-scale fingering. Narrow domains, however, should still be used with caution since they could limit the subsequent development of any large-scale dynamics typically associated with fingering convection.
Prinz, V Ya; Seleznev, Vladimir
2016-12-13
It is a well-known fact that bone scaffold topography on micro- and nanometer scale influences the cellular behavior. Nano-scale surface modification of scaffolds allows the modulation of biological activity for enhanced cell differentiation. To date, there has been only a limited success in printing scaffolds with micro- and nano-scale features exposed on the surface. To improve on the currently available imperfect technologies, in our paper we introduce new hybrid technologies based on a combination of 2D (nano imprint) and 3D printing methods. The first method is based on using light projection 3D printing and simultaneous 2D nanostructuring of each of the layers during the formation of the 3D structure. The second method is based on the sequential integration of preliminarily created 2D nanostructured films into a 3D printed structure. The capabilities of the developed hybrid technologies are demonstrated with the example of forming 3D bone scaffolds. The proposed technologies can be used to fabricate complex 3D micro- and nanostructured products for various fields.
Widom, Julia R; Johnson, Neil P; von Hippel, Peter H; Marcus, Andrew H
2013-02-01
We have observed the conformation-dependent electronic coupling between the monomeric subunits of a dinucleotide of 2-aminopurine (2-AP), a fluorescent analog of the nucleic acid base adenine. This was accomplished by extending two-dimensional fluorescence spectroscopy (2D FS) - a fluorescence-detected variation of 2D electronic spectroscopy - to excite molecular transitions in the ultraviolet (UV) regime. A collinear sequence of four ultrafast laser pulses centered at 323 nm was used to resonantly excite the coupled transitions of 2-AP dinucleotide. The phases of the optical pulses were continuously swept at kilohertz frequencies, and the ensuing nonlinear fluorescence was phase-synchronously detected at 370 nm. Upon optimization of a point-dipole coupling model to our data, we found that in aqueous buffer the 2-AP dinucleotide adopts an average conformation in which the purine bases are non-helically stacked (center-to-center distance R12 = 3.5 Å ± 0.5 Å, twist angle θ12 = 5° ± 5°), which differs from the conformation of such adjacent bases in duplex DNA. These experiments establish UV-2D FS as a method for examining the local conformations of an adjacent pair of fluorescent nucleotides substituted into specific DNA or RNA constructs, which will serve as a powerful probe to interpret, in structural terms, biologically significant local conformational changes within the nucleic acid framework of protein-nucleic acid complexes.
Sun, Liyun; Gu, Shaohua; Sun, Yaqiong; Zheng, Dan; Wu, Qihan; Li, Xin; Dai, Jianfeng; Dai, Jianliang; Ji, Chaoneng; Xie, Yi; Mao, Yumin
2005-04-01
This study reports the cloning and characterization of a novel human phosphatidic acid phosphatase type 2 isoform cDNAs (PAP2d) from the foetal brain cDNA library. The PAP2d gene is localized on chromosome 1p21.3. It contains six exons and spans 112 kb of the genomic DNA. By large-scale cDNA sequencing we found two splice variants of PAP2d, PAP2d_v1 and PAP2d_v2. The PAP2d_v1 cDNA is 1722 bp in length and spans an open reading frame from nucleotide 56 to 1021, encoding a 321aa protein. The PAP2d_v2 cDNA is 1707 bp in length encoding a 316aa protein from nucleotide 56-1006. The PAP2d_v1 cDNA is 15 bp longer than the PAP2d_v2 cDNA in the terminal of the fifth exon and it creates different ORF. Both of the proteins contain a well-conserved PAP2 motif. The PAP2d_v1 is mainly expressed in human brain, lung, kidney, testis and colon, while PAP2d_v2 is restricted to human placenta, skeletal muscle, and kidney. The two splice variants are co-expressed only in kidney.
2D Seismic Reflection Data across Central Illinois
Smith, Valerie; Leetaru, Hannes
2014-09-30
In a continuing collaboration with the Midwest Geologic Sequestration Consortium (MGSC) on the Evaluation of the Carbon Sequestration Potential of the Cambro-Ordovician Strata of the Illinois and Michigan Basins project, Schlumberger Carbon Services and WesternGeco acquired two-dimensional (2D) seismic data in the Illinois Basin. This work included the design, acquisition and processing of approximately 125 miles of (2D) seismic reflection surveys running west to east in the central Illinois Basin. Schlumberger Carbon Services and WesternGeco oversaw the management of the field operations (including a pre-shoot planning, mobilization, acquisition and de-mobilization of the field personnel and equipment), procurement of the necessary permits to conduct the survey, post-shoot closure, processing of the raw data, and provided expert consultation as needed in the interpretation of the delivered product. Three 2D seismic lines were acquired across central Illinois during November and December 2010 and January 2011. Traversing the Illinois Basin, this 2D seismic survey was designed to image the stratigraphy of the Cambro-Ordovician sections and also to discern the basement topography. Prior to this survey, there were no regionally extensive 2D seismic data spanning this section of the Illinois Basin. Between the NW side of Morgan County and northwestern border of Douglas County, these seismic lines ran through very rural portions of the state. Starting in Morgan County, Line 101 was the longest at 93 miles in length and ended NE of Decatur, Illinois. Line 501 ran W-E from the Illinois Basin – Decatur Project (IBDP) site to northwestern Douglas County and was 25 miles in length. Line 601 was the shortest and ran N-S past the IBDP site and connected lines 101 and 501. All three lines are correlated to well logs at the IBDP site. Originally processed in 2011, the 2D seismic profiles exhibited a degradation of signal quality below ~400 millisecond (ms) which made
Moment domain representation of nonblind image deblurring.
Kumar, Ahlad; Paramesran, Raveendran; Shakibaei, Barmak Honarvar
2014-04-01
In this paper, we propose the use of geometric moments to the field of nonblind image deblurring. Using the developed relationship of geometric moments for original and blurred images, a mathematical formulation based on the Euler-Lagrange identity and variational techniques is proposed. It uses an iterative procedure to deblur the image in moment domain. The theoretical framework is validated by a set of experiments. A comparative analysis of the results obtained using the spatial and moment domains are evaluated using a quality assessment method known as the Blind/Reference-less Image Spatial Quality Evaluator (BRISQUE). The results show that the proposed method yields a higher quality score when compared with the spatial domain method for the same number of iterations.
Magnetic moments in graphene with vacancies.
Chen, Jing-Jing; Wu, Han-Chun; Yu, Da-Peng; Liao, Zhi-Min
2014-08-07
Vacancies can induce local magnetic moments in graphene, paving the way to make magnetic functional graphene. Due to the interaction between magnetic moments and conduction carriers, the magnetotransport properties of graphene can be modulated. Here, the effects of vacancy induced magnetic moments on the electrical properties of graphene are studied via magnetotransport measurements and spin-polarized density functional theory calculations. We show by quantum Hall measurements that a sharp resonant Vπ state is introduced in the midgap region of graphene with vacancies, resulting in the local magnetic moment. The coupling between the localized Vπ state and the itinerant carrier is tuned by varying the carrier concentration, temperature, magnetic field, and vacancy density, which results in a transition between hopping transport and the Kondo effect and a transition between giant negative magnetoresistance (MR) and positive MR. This modulated magnetotransport is valuable for graphene based spintronic devices.
Neutrino masses, mixing, moments, and matter
Marciano, W.J.
1988-01-01
The present status of neutrino masses, mixing, and electromagnetic moments is surveyed. Potential enhancements of neutrino oscillations, decay, and spin-flavor precession due to their interactions with matter are described.
NASA Astrophysics Data System (ADS)
de la Fuente Marcos, C.; de la Fuente Marcos, R.
2015-08-01
Context. Asteroids with semi-major axes very close to that of a host planet can avoid node crossings when their nodal points are at perihelion and at aphelion. This layout protects the asteroids from close encounters, and eventual collisions, with the host planet. Aims: Here, we study the short-term dynamical evolution of four recently discovered near-Earth asteroids (NEAs) - 2012 FC71, 2014 EK24, 2014 QD364, and 2014 UR - that follow very Earth-like orbits. Methods: Our analysis is based on results of direct N-body calculations that use the most updated ephemerides and include perturbations from the eight major planets, the Moon, the barycentre of the Pluto-Charon system, and the three largest asteroids. Results: These four NEAs exhibit an orbital evolution unlike any other known near-Earth object (NEO). Beyond horseshoe, tadpole, or quasi-satellite trajectories, they follow co-orbital passing orbits relative to the Earth within the Kozai domain. Our calculations show that secular interactions induce librations of their relative argument of perihelion with respect to our planet but also to Venus, Mars, and Jupiter. Secular chaos is also present. The size of this transient population is probably large. Conclusions: Although some of these NEAs can remain orbitally stable for many thousands of years, their secular dynamics are substantially more complicated than commonly thought and cannot be properly described within the framework of the three-body problem alone owing to the overlapping of multiple secular resonances. Objects in this group are amongst the most atypical NEOs regarding favourable visibility windows because these are separated in time by many decades or even several centuries. Figures 2, 3, 5, 7, 9, 11, 13, 15, 17, 18, Table 2, and Appendix A are available in electronic form at http://www.aanda.org
Human erythrocytes analyzed by generalized 2D Raman correlation spectroscopy
NASA Astrophysics Data System (ADS)
Wesełucha-Birczyńska, Aleksandra; Kozicki, Mateusz; Czepiel, Jacek; Łabanowska, Maria; Nowak, Piotr; Kowalczyk, Grzegorz; Kurdziel, Magdalena; Birczyńska, Malwina; Biesiada, Grażyna; Mach, Tomasz; Garlicki, Aleksander
2014-07-01
The most numerous elements of the blood cells, erythrocytes, consist mainly of two components: homogeneous interior filled with hemoglobin and closure which is the cell membrane. To gain insight into their specific properties we studied the process of disintegration, considering these two constituents, and comparing the natural aging process of human healthy blood cells. MicroRaman spectra of hemoglobin within the single RBC were recorded using 514.5, and 785 nm laser lines. The generalized 2D correlation method was applied to analyze the collected spectra. The time passed from blood donation was regarded as an external perturbation. The time was no more than 40 days according to the current storage limit of blood banks, although, the average RBC life span is 120 days. An analysis of the prominent synchronous and asynchronous cross peaks allow us to get insight into the mechanism of hemoglobin decomposition. Appearing asynchronous cross-peaks point towards globin and heme separation from each other, while synchronous shows already broken globin into individual amino acids. Raman scattering analysis of hemoglobin "wrapping", i.e. healthy erythrocyte ghosts, allows for the following peculiarity of their behavior. The increasing power of the excitation laser induced alterations in the assemblage of membrane lipids. 2D correlation maps, obtained with increasing laser power recognized as an external perturbation, allows for the consideration of alterations in the erythrocyte membrane structure and composition, which occurs first in the proteins. Cross-peaks were observed indicating an asynchronous correlation between the senescent-cell antigen (SCA) and heme or proteins vibrations. The EPR spectra of the whole blood was analyzed regarding time as an external stimulus. The 2D correlation spectra points towards participation of the selected metal ion centers in the disintegration process.
Digit ratio (2D:4D), salivary testosterone, and handedness.
Beaton, Alan A; Rudling, Nick; Kissling, Christian; Taurines, Regine; Thome, Johannes
2011-03-01
The length of the index finger relative to that of the ring finger, the 2D:4D ratio, has been taken to be a marker of the amount of testosterone (T) that was present in the foetal environment (Manning, Scutt, Wilson, & Lewis-Jones, 1998). It has also been suggested (Geschwind & Galaburda, 1987) that elevated levels of foetal T are associated with left-handedness and that adult levels of circulating T might relate to foetal levels (Jamison, Meier, & Campbell, 1993). We used multiple regression analyses to investigate whether there is any relationship between either left or right hand 2D:4D ratio and handedness. We also examined whether adult levels of salivary T (or cortisol, used as a control hormone) predict digit ratio and/or handedness. Although the 2D:4D ratio of neither the left nor the right hand was related to handedness, the difference between the digit ratios of the right and left hands, D(R-L), was a significant predictor of handedness and of the performance difference between the hands on a peg-moving task, supporting previous findings (Manning & Peters, 2009; Manning et al., 1998; Manning, Trivers, Thornhill, & Singh, 2000; Stoyanov, Marinov, & Pashalieva, 2009). Adult circulating T levels did not predict the digit ratio of the left or right hand; nor was there a significant relationship between concentrations of salivary T (or cortisol) and either hand preference or asymmetry in manual skill. We suggest that the association between D(R-L) and hand preference arises because D(R-L) is a correlate of sensitivity to T in the developing foetus.
Quantitation of protein in samples prepared for 2-D electrophoresis.
Berkelman, Tom
2008-01-01
The concentration of protein in a sample prepared for two dimensional (2-D) electrophoretic analysis is usually determined by protein assay. Reasons for this include the following. (1) Protein quantitation ensures that the amount of protein to be separated is appropriate for the gel size and visualization method. (2) Protein quantitation facilitates comparison among similar samples, as image-based analysis is simplified when equivalent quantities of proteins have been loaded on the gels to be compared. (3) Quantitation is necessary in cases where the protein sample is labeled with dye before separation (1,2). The labeling chemistry is affected by the dye to protein ratio so it is essential to know the protein concentration before setting up the labeling reaction.A primary consideration with quantitating protein in samples prepared for 2-D electrophoresis is interference by nonprotein substances that may be present in the sample. These samples generally contain chaotropic solubilizing agents, detergents, reductants, buffers or carrier ampholytes, all of which potentially interfere with protein quantitation. The most commonly used protein assays in proteomics research are colorimetric assays in which the presence of protein causes a color change that can be measured spectrophotometrically (3). All protein assays utilize standards, a dilution series of a known concentration of a known protein, to create a standard curve. Two methods will be considered that circumvent some of the problems associated with interfering substances and are well suited for samples prepared for 2-D electrophoresis. The first method (4.1.1) relies on a color change that occurs upon binding of a dye to protein and the second (4.1.2) relies on binding and reduction of cupric ion (Cu2+) ion to cuprous ion (Cu+) by proteins.
2D to 3D conversion implemented in different hardware
NASA Astrophysics Data System (ADS)
Ramos-Diaz, Eduardo; Gonzalez-Huitron, Victor; Ponomaryov, Volodymyr I.; Hernandez-Fragoso, Araceli
2015-02-01
Conversion of available 2D data for release in 3D content is a hot topic for providers and for success of the 3D applications, in general. It naturally completely relies on virtual view synthesis of a second view given by original 2D video. Disparity map (DM) estimation is a central task in 3D generation but still follows a very difficult problem for rendering novel images precisely. There exist different approaches in DM reconstruction, among them manually and semiautomatic methods that can produce high quality DMs but they demonstrate hard time consuming and are computationally expensive. In this paper, several hardware implementations of designed frameworks for an automatic 3D color video generation based on 2D real video sequence are proposed. The novel framework includes simultaneous processing of stereo pairs using the following blocks: CIE L*a*b* color space conversions, stereo matching via pyramidal scheme, color segmentation by k-means on an a*b* color plane, and adaptive post-filtering, DM estimation using stereo matching between left and right images (or neighboring frames in a video), adaptive post-filtering, and finally, the anaglyph 3D scene generation. Novel technique has been implemented on DSP TMS320DM648, Matlab's Simulink module over a PC with Windows 7, and using graphic card (NVIDIA Quadro K2000) demonstrating that the proposed approach can be applied in real-time processing mode. The time values needed, mean Similarity Structural Index Measure (SSIM) and Bad Matching Pixels (B) values for different hardware implementations (GPU, Single CPU, and DSP) are exposed in this paper.
Numerical modelling of spallation in 2D hydrodynamics codes
NASA Astrophysics Data System (ADS)
Maw, J. R.; Giles, A. R.
1996-05-01
A model for spallation based on the void growth model of Johnson has been implemented in 2D Lagrangian and Eulerian hydrocodes. The model has been extended to treat complete separation of material when voids coalesce and to describe the effects of elevated temperatures and melting. The capabilities of the model are illustrated by comparison with data from explosively generated spall experiments. Particular emphasis is placed on the prediction of multiple spall effects in weak, low melting point, materials such as lead. The correlation between the model predictions and observations on the strain rate dependence of spall strength is discussed.
Beam-Plasma Instabilities in a 2D Yukawa Lattice
Kyrkos, S.; Kalman, G. J.; Rosenberg, M.
2009-06-05
We consider a 2D Yukawa lattice of grains, with a beam of other charged grains moving in the lattice plane. In contrast to Vlasov plasmas, where the electrostatic instability excited by the beam is only longitudinal, here both longitudinal and transverse instabilities of the lattice phonons can develop. We determine and compare the transverse and longitudinal growth rates. The growth rate spectrum in wave number space exhibits remarkable gaps where no instability can develop. Depending on the system parameters, the transverse instability can be selectively excited.
Transport Experiments on 2D Correlated Electron Physics in Semiconductors
Tsui, Daniel
2014-03-24
This research project was designed to investigate experimentally the transport properties of the 2D electrons in Si and GaAs, two prototype semiconductors, in several new physical regimes that were previously inaccessible to experiments. The research focused on the strongly correlated electron physics in the dilute density limit, where the electron potential energy to kinetic energy ratio rs>>1, and on the fractional quantum Hall effect related physics in nuclear demagnetization refrigerator temperature range on samples with new levels of purity and controlled random disorder.
Quantum Oscillations in an Interfacial 2D Electron Gas.
Zhang, Bingop; Lu, Ping; Liu, Henan; Lin, Jiao; Ye, Zhenyu; Jaime, Marcelo; Balakirev, Fedor F.; Yuan, Huiqiu; Wu, Huizhen; Pan, Wei; Zhang, Yong
2016-01-01
Recently, it has been predicted that topological crystalline insulators (TCIs) may exist in SnTe and Pb_{1-x}Sn_{x}Te thin films [1]. To date, most studies on TCIs were carried out either in bulk crystals or thin films, and no research activity has been explored in heterostructures. We present here the results on electronic transport properties of the 2D electron gas (2DEG) realized at the interfaces of PbTe/ CdTe (111) heterostructures. Evidence of topological state in this interfacial 2DEG was observed.
2D Magneto-Optical Trapping of Diatomic Molecules
NASA Astrophysics Data System (ADS)
Hummon, Matthew T.; Yeo, Mark; Stuhl, Benjamin K.; Collopy, Alejandra L.; Xia, Yong; Ye, Jun
2013-04-01
We demonstrate one- and two-dimensional transverse laser cooling and magneto-optical trapping of the polar molecule yttrium (II) oxide (YO). In a 1D magneto-optical trap (MOT), we characterize the magneto-optical trapping force and decrease the transverse temperature by an order of magnitude, from 25 to 2 mK, limited by interaction time. In a 2D MOT, we enhance the intensity of the YO beam and reduce the transverse temperature in both transverse directions. The approach demonstrated here can be applied to many molecular species and can also be extended to 3D.
Black liquor gasification phase 2D final report
Kohl, A.L.; Stewart, A.E.
1988-06-01
This report covers work conducted by Rockwell International under Amendment 5 to Subcontract STR/DOE-12 of Cooperative Agreement DE-AC-05-80CS40341 between St. Regis Corporation (now Champion International) and the Department of Energy (DOE). The work has been designated Phase 2D of the overall program to differentiate it from prior work under the same subcontract. The overall program is aimed at demonstrating the feasibility of and providing design data for the Rockwell process for gasifying Kraft black liquor. In this process, concentrated black liquor is converted into low-Btu fuel gas and reduced melt by reaction with air in a specially designed gasification reactor.
2D/3D Synthetic Vision Navigation Display
NASA Technical Reports Server (NTRS)
Prinzel, Lawrence J., III; Kramer, Lynda J.; Arthur, J. J., III; Bailey, Randall E.; Sweeters, jason L.
2008-01-01
Flight-deck display software was designed and developed at NASA Langley Research Center to provide two-dimensional (2D) and three-dimensional (3D) terrain, obstacle, and flight-path perspectives on a single navigation display. The objective was to optimize the presentation of synthetic vision (SV) system technology that permits pilots to view multiple perspectives of flight-deck display symbology and 3D terrain information. Research was conducted to evaluate the efficacy of the concept. The concept has numerous unique implementation features that would permit enhanced operational concepts and efficiencies in both current and future aircraft.
Experimental validation of 2-D generalized geometric super resolved approach
NASA Astrophysics Data System (ADS)
Borkowski, Amikam; Zalevsky, Zeev; Cohen, Nadav; Hadas, Zadok; Marom, Emanuel; Javidi, Bahram
2014-01-01
In this paper, we generalize the method of using a 2-D moving binary random mask to overcome the geometrical resolution limitation of an imaging sensor. The spatial blurring is caused by the size of the imaging sensor pixels which yield insufficient spatial sampling. The mask is placed in an intermediate image plane and can be shifted in any direction while keeping the sensor as well as all other optical components fixed. Out of the set of images that are captured and registered, a high resolution image can be composed. In addition, this proposed approach reduces the amount of required computations and it has an improved robustness to spatial noise.
NGMIX: Gaussian mixture models for 2D images
NASA Astrophysics Data System (ADS)
Sheldon, Erin
2015-08-01
NGMIX implements Gaussian mixture models for 2D images. Both the PSF profile and the galaxy are modeled using mixtures of Gaussians. Convolutions are thus performed analytically, resulting in fast model generation as compared to methods that perform the convolution in Fourier space. For the galaxy model, NGMIX supports exponential disks and de Vaucouleurs and Sérsic profiles; these are implemented approximately as a sum of Gaussians using the fits from Hogg & Lang (2013). Additionally, any number of Gaussians can be fit, either completely free or constrained to be cocentric and co-elliptical.
Ultrathin 2D Metal-Organic Framework Nanosheets.
Zhao, Meiting; Wang, Yixian; Ma, Qinglang; Huang, Ying; Zhang, Xiao; Ping, Jianfeng; Zhang, Zhicheng; Lu, Qipeng; Yu, Yifu; Xu, Huan; Zhao, Yanli; Zhang, Hua
2015-12-02
A facile surfactant-assisted bottom-up synthetic method to prepare a series of freestanding ultrathin 2D M-TCPP (M = Zn, Cu, Cd or Co, TCPP = tetrakis(4-carboxyphenyl)porphyrin) nanosheets with a thickness of sub-10 nm is developed. As a proof-of-concept application, some of them are successfully used as new platforms for DNA detection. The Cu-TCPP nanosheet-based sensor shows excellent fluorescent sensing performance and is used for the simultaneous detection of multiple DNA targets.
2D photonic crystal and its angular reflective azimuthal spectrum
NASA Astrophysics Data System (ADS)
Senderakova, Dagmar; Drzik, Milan; Tomekova, Juliana
2016-12-01
Contemporary, attention is paid to photonic crystals, which can strongly modify light propagation through them and enable a controllable light manipulation. The contribution is focused on a sub-wavelength 2D structure formed by Al2O3 layer on silicon substrate, patterned with periodic hexagonal lattice of deep air holes. Using various laser sources of light at single wavelength, azimuthal angle dependence of the mirror-like reflected light intensity was recorded photo-electrically. The results obtained can be used to sample the band-structure of leaky modes of the photonic crystal more reliably and help us to map the photonic dispersion diagram.
Quantifying Therapeutic and Diagnostic Efficacy in 2D Microvascular Images
NASA Technical Reports Server (NTRS)
Parsons-Wingerter, Patricia; Vickerman, Mary B.; Keith, Patricia A.
2009-01-01
VESGEN is a newly automated, user-interactive program that maps and quantifies the effects of vascular therapeutics and regulators on microvascular form and function. VESGEN analyzes two-dimensional, black and white vascular images by measuring important vessel morphology parameters. This software guides the user through each required step of the analysis process via a concise graphical user interface (GUI). Primary applications of the VESGEN code are 2D vascular images acquired as clinical diagnostic images of the human retina and as experimental studies of the effects of vascular regulators and therapeutics on vessel remodeling.
Fracture surfaces of heterogeneous materials: A 2D solvable model
NASA Astrophysics Data System (ADS)
Katzav, E.; Adda-Bedia, M.; Derrida, B.
2007-05-01
Using an elastostatic description of crack growth based on the Griffith criterion and the principle of local symmetry, we present a stochastic model describing the propagation of a crack tip in a 2D heterogeneous brittle material. The model ensures the stability of straight cracks and allows for the study of the roughening of fracture surfaces. When neglecting the effect of the nonsingular stress, the problem becomes exactly solvable and yields analytic predictions for the power spectrum of the paths. This result suggests an alternative to the conventional power law analysis often used in the analysis of experimental data.
Optical diffraction by ordered 2D arrays of silica microspheres
NASA Astrophysics Data System (ADS)
Shcherbakov, A. A.; Shavdina, O.; Tishchenko, A. V.; Veillas, C.; Verrier, I.; Dellea, O.; Jourlin, Y.
2017-03-01
The article presents experimental and theoretical studies of angular dependent diffraction properties of 2D monolayer arrays of silica microspheres. High-quality large area defect-free monolayers of 1 μm diameter silica microspheres were deposited by the Langmuir-Blodgett technique under an accurate optical control. Measured angular dependencies of zeroth and one of the first order diffraction efficiencies produced by deposited samples were simulated by the rigorous Generalized Source Method taking into account particle size dispersion and lattice nonideality.
Efficient 2d full waveform inversion using Fortran coarray
NASA Astrophysics Data System (ADS)
Ryu, Donghyun; Kim, ahreum; Ha, Wansoo
2016-04-01
We developed a time-domain seismic inversion program using the coarray feature of the Fortran 2008 standard to parallelize the algorithm. We converted a 2d acoustic parallel full waveform inversion program with Message Passing Interface (MPI) to a coarray program and examined performance of the two inversion programs. The results show that the speed of the waveform inversion program using the coarray is slightly faster than that of the MPI version. The standard coarray lacks features for collective communication; however, it can be improved in following standards since it is introduced recently. The parallel algorithm can be applied for 3D seismic data processing.
Interplay between Anderson and Stark Localization in 2D Lattices
Kolovsky, A. R.
2008-11-07
This Letter studies the dynamics of a quantum particle in 2D lattices with on-site disorder in the presence of a static field. It is shown that the particle is localized along the field direction, while in the orthogonal direction to the field it shows diffusive dynamics for algebraically large times. For weak disorder an analytical expression for the diffusion coefficient is obtained by mapping the problem to a band random matrix. This expression is confirmed by numerical simulations of the particle's dynamics, which also indicate the existence of a universal equation for the diffusion coefficient, valid for an arbitrary disorder strength.
Calculation of 2D electronic band structure using matrix mechanics
NASA Astrophysics Data System (ADS)
Pavelich, R. L.; Marsiglio, F.
2016-12-01
We extend previous work, applying elementary matrix mechanics to one-dimensional periodic arrays (to generate energy bands), to two-dimensional arrays. We generate band structures for the square-lattice "2D Kronig-Penney model" (square wells), the "muffin-tin" potential (circular wells), and Gaussian wells. We then apply the method to periodic arrays of more than one atomic site in a unit cell, specifically to the case of materials with hexagonal lattices like graphene. These straightforward extensions of undergraduate-level calculations allow students to readily determine band structures of current research interest.
Dynamics of Quarks in a 2D Flux Tube
Koshelkin, Andrey V.; Wong, Cheuk-Yin
2015-01-01
On the basis of a compactification of the (3+1) into (1+1) dimensional space-time [1], the quark states inside the 2D flux tube are studied for the case of a linear transverse confining potential. The derived states are classified by both the projections of the orbital momentum and the spin along the tube direction. The spectrum of the fermion states is evaluated. It is found that the energy eigenvalues of the quarks appear to be approximately related to the square root of the eigenvalues of the two-dimensional harmonic oscillator.
Magnetic dipole moments for composite dark matter
Aranda, Alfredo; Barajas, Luis; Cembranos, Jose A.R. E-mail: luisedua@buffalo.edu
2016-03-01
We study neutral dark matter candidates with a nonzero magnetic dipole moment. We assume that they are composite states of new fermions related to the strong phase of a new gauge interaction. In particular, invoking a dark flavor symmetry, we analyze the composition structure of viable candidates depending on the assignations of hypercharge and the multiplets associated to the fundamental constituents of the extended sector. We determine the magnetic dipole moments for the neutral composite states in terms of their constituents masses.
Droplet-model predictions of charge moments
Myers, W.D.
1982-04-01
The Droplet Model expressions for calculating various moments of the nuclear charge distribution are given. There are contributions to the moments from the size and shape of the system, from the internal redistribution induced by the Coulomb repulsion, and from the diffuseness of the surface. A case is made for the use of diffuse charge distributions generated by convolution as an alternative to Fermi-functions.
Toroidal Dipole Moment of a Massless Neutrino
Cabral-Rosetti, L. G.; Mondragon, M.; Perez, E. Reyes
2009-04-20
We obtain the toroidal dipole moment of a massless neutrino {tau}{sub v{sub I}}{sup M} using the results for the anapole moment of a massless Dirac neutrino a{sub v{sub I}}{sup D}, which was obtained in the context of the Standard Model of the electroweak interactions (SM)SU(2){sub L} x U(1){sub Y}.
On the dipole moment of CO/+/.
NASA Technical Reports Server (NTRS)
Certain, P. R.; Woods, R. C.
1973-01-01
Results of self-consistent field calculations on neutral CO, its positive ion, and on neutral CN to verify an earlier estimate of the dipole moment of CO(+) in its ground super 2 Sigma state. Based on the above-mentioned calculations, direct evidence is obtained that the dipole moment (relative to the center of mass) is approximately 2.5 plus or minus 0.5 C, as previously determined by Kopelman and Klemperer (1962).
Ti3CrCu4: A possible 2-D ferromagnetic spin fluctuating system
NASA Astrophysics Data System (ADS)
Dhar, S. K.; Provino, A.; Manfrinetti, P.; Kulkarni, R.; Goyal, Neeraj; Paudyal, D.
2016-05-01
Ti3CrCu4 is a new ternary compound which crystallizes in the tetragonal Ti3Pd5 structure type. The Cr atoms form square nets in the a-b plane (a = 3.124 Å) which are separated by an unusually large distance c = 11.228 Å along the tetragonal axis, thus forming a -2-D Cr-sublattice. The paramagnetic susceptibility is characterized by a low effective moment, μeff = 1.1 μB, a low paramagnetic Curie temperature θP (below 7 K) and a temperature independent χ0 = 6.7 x 10-4 emu/mol. The magnetization at 1.8 K increases rapidly with field nearly saturating to 0.2 μB/f.u. The zero field heat capacity C/T shows an upturn below 7 K (˜190 mJ/mol K2 at ˜0.1K) which is suppressed in applied magnetic fields and interpreted as suggesting the presence of spin fluctuations. The resistivity at low temperatures shows non-Fermi liquid behavior. Overall, the experimental data thus reveal an unusual magnetic state in Ti3CrCu4, which likely has its origin in the layered nature of the Cr sub-lattice and ferromagnetic spin fluctuations. Density functional theoretical calculations reveal a sharp Cr density of states peak just above the Fermi level, indicating the propensity of Ti3CrCu4 to become magnetic.
2D CFD Analysis of an Airfoil with Active Continuous Trailing Edge Flap
NASA Astrophysics Data System (ADS)
Jaksich, Dylan; Shen, Jinwei
2014-11-01
Efficient and quieter helicopter rotors can be achieved through on-blade control devices, such as active Continuous Trailing-Edge Flaps driven by embedded piezoelectric material. This project aims to develop a CFD simulation tool to predict the aerodynamic characteristics of an airfoil with CTEF using open source code: OpenFOAM. Airfoil meshes used by OpenFOAM are obtained with MATLAB scripts. Once created it is possible to rotate the airfoil to various angles of attack. When the airfoil is properly set up various OpenFOAM properties, such as kinematic viscosity and flow velocity, are altered to achieve the desired testing conditions. Upon completion of a simulation, the program gives the lift, drag, and moment coefficients as well as the pressure and velocity around the airfoil. The simulation is then repeated across multiple angles of attack to give full lift and drag curves. The results are then compared to previous test data and other CFD predictions. This research will lead to further work involving quasi-steady 2D simulations incorporating NASTRAN to model aeroelastic deformation and eventually to 3D aeroelastic simulations. NSF ECE Grant #1358991 supported the first author as an REU student.
Modeling of two-storey precast school building using Ruaumoko 2D program
Hamid, N. H.; Tarmizi, L. H.; Ghani, K. D.
2015-05-15
The long-distant earthquake loading from Sumatra and Java Island had caused some slight damages to precast and reinforced concrete buildings in West Malaysia such as cracks on wall panels, columns and beams. Subsequently, the safety of existing precast concrete building is needed to be analyzed because these buildings were designed using BS 8110 which did not include the seismic loading in the design. Thus, this paper emphasizes on the seismic performance and dynamic behavior of precast school building constructed in Malaysia under three selected past earthquakes excitations ; El Centro 1940 North-South, El Centro East-West components and San Fernando 1971 using RUAUMOKO 2D program. This program is fully utilized by using prototype precast school model and dynamic non-linear time history analysis. From the results, it can be concluded that two-storey precast school building has experienced severe damage and partial collapse especially at beam-column joint under San Fernando and El Centro North-South Earthquake as its exceeds the allowable inter-storey drift and displacement as specified in Eurocode 8. The San Fernando earthquake has produced a massive destruction to the precast building under viscous damping, ξ = 5% and this building has generated maximum building displacement of 435mm, maximum building drift of 0.68% and maximum bending moment at 8458kNm.
Modeling of two-storey precast school building using Ruaumoko 2D program
NASA Astrophysics Data System (ADS)
Hamid, N. H.; Tarmizi, L. H.; Ghani, K. D.
2015-05-01
The long-distant earthquake loading from Sumatra and Java Island had caused some slight damages to precast and reinforced concrete buildings in West Malaysia such as cracks on wall panels, columns and beams. Subsequently, the safety of existing precast concrete building is needed to be analyzed because these buildings were designed using BS 8110 which did not include the seismic loading in the design. Thus, this paper emphasizes on the seismic performance and dynamic behavior of precast school building constructed in Malaysia under three selected past earthquakes excitations ; El Centro 1940 North-South, El Centro East-West components and San Fernando 1971 using RUAUMOKO 2D program. This program is fully utilized by using prototype precast school model and dynamic non-linear time history analysis. From the results, it can be concluded that two-storey precast school building has experienced severe damage and partial collapse especially at beam-column joint under San Fernando and El Centro North-South Earthquake as its exceeds the allowable inter-storey drift and displacement as specified in Eurocode 8. The San Fernando earthquake has produced a massive destruction to the precast building under viscous damping, ξ = 5% and this building has generated maximum building displacement of 435mm, maximum building drift of 0.68% and maximum bending moment at 8458kNm.
Boutilier, Joseph M; Warden, Hunter; Doucette, Alan A; Wentzell, Peter D
2012-11-01
The differential separation of deuterated and non-deuterated forms of isotopically substituted compounds in chromatography is a well-known but not well-understood phenomenon. This separation is relevant in comparative proteomics, where stable isotopes are used for differential labelling and the effect of isotope resolution on quantitation has been used to disqualify some deuterium labelling methods in favour of heavier isotopes. In this work, a detailed evaluation of the extent of isotopic separation and its impact on quantitation was performed for peptides labelled through dimethylation with H(2)/D(2) formaldehyde. The chromatographic behaviour of 71 labelled peptide pairs from quadruplicate tryptic digests of bovine serum albumin were analysed, focusing on differences in median retention times, resolution, and relative quantitation for each peptide. For 94% of peptides, the retention time difference (heavy-light) was less than 12s with a median value 3.4s. With the exception of a single anomalous pair, isotope resolution was below 0.6 with a median value 0.11. Quantitative assessment indicates that the bias in ratio calculation introduced by retention time shifts is only about 3%, substantially smaller than the variation in ratio measurements themselves. Computational studies on the dipole moments of deuterated labels indicate that these results are consistent with literature suggestions that retention time shifts are inversely related to the polarity of the label. This study suggests that the incorporation of deuterium isotopes through peptide dimethylation at amine residues is a viable route to proteome quantitation.
NASA Astrophysics Data System (ADS)
Tassi, E.
2015-11-01
We present an infinite family of Hamiltonian electromagnetic fluid models for plasmas, derived from drift-kinetic equations. An infinite hierarchy of fluid equations is obtained from a Hamiltonian drift-kinetic system by taking moments of a generalized distribution function and using Hermite polynomials as weight functions of the velocity coordinate along the magnetic guide field. Each fluid model is then obtained by truncating the hierarchy to a finite number N + 1 of equations by means of a closure relation. We show that, for any positive N, a linear closure relation between the moment of order N + 1 and the moment of order N guarantees that the resulting fluid model possesses a Hamiltonian structure, thus respecting the Hamiltonian character of the parent drift-kinetic model. An orthogonal transformation is identified which maps the fluid moments to a new set of dynamical variables in terms of which the Poisson brackets of the fluid models become a direct sum and which unveils remarkable dynamical properties of the models in the two-dimensional (2D) limit. Indeed, when imposing translational symmetry with respect to the direction of the magnetic guide field, all models belonging to the infinite family can be reformulated as systems of advection equations for Lagrangian invariants transported by incompressible generalized velocities. These are reminiscent of the advection properties of the parent drift-kinetic model in the 2D limit and are related to the Casimirs of the Poisson brackets of the fluid models. The Hamiltonian structure of the generic fluid model belonging to the infinite family is illustrated treating a specific example of a fluid model retaining five moments in the electron dynamics and two in the ion dynamics. We also clarify the connection existing between the fluid models of this infinite family and some fluid models already present in the literature.
Moments of fusion-barrier distributions
NASA Astrophysics Data System (ADS)
Rehm, K. E.; Esbensen, H.; Jiang, C. L.; Back, B. B.; Stefanini, A. M.; Montagnoli, G.
2016-10-01
A study of fusion-barrier distributions through an analysis of their moments is presented. The moments can be obtained from least-squares fits of the energy-weighted fusion cross sections without the need of calculating second derivatives. The zeroth and first moments determine the fusion radius R and the Coulomb barrier VC. These two quantities are the same as the parameters R and VC that are used in the well-known expression, E σ =π R2(E -VC) , for the fusion cross section at high energies. The second and third moments, M2 and M3, determine the width and skewness of the barrier distribution, respectively. From these global parameters new correlations for the study of heavy-ion-induced fusion reactions can be obtained. Systems exhibiting a large coupling to transfer reactions show a small fusion radius as well as a large second moment. A negative third moment is correlated with a prolate deformation of the target nucleus.
NASA Astrophysics Data System (ADS)
Roostaei, B.; Ermler, W. C.
2012-03-01
A procedure for calculating electric dipole transition moments and permanent dipole moments from spin-orbit configuration interaction (SOCI) wave functions has been developed in the context of the COLUMBUS ab initio electronic structure programs. The SOCI procedure requires relativistic effective core potentials and their corresponding spin-orbit coupling operators to define the molecular Hamiltonian, electric dipole transition moment and permanent dipole moment matrices. The procedure can be used for any molecular system for which the COLUMBUS SOCI circuits are applicable. Example applications are reported for transition moments and dipole moments for a series of electronic states of LiBe and LiSr defined in diatomic relativistic ωω-coupling.
3D surface configuration modulates 2D symmetry detection.
Chen, Chien-Chung; Sio, Lok-Teng
2015-02-01
We investigated whether three-dimensional (3D) information in a scene can affect symmetry detection. The stimuli were random dot patterns with 15% dot density. We measured the coherence threshold, or the proportion of dots that were the mirror reflection of the other dots in the other half of the image about a central vertical axis, at 75% accuracy with a 2AFC paradigm under various 3D configurations produced by the disparity between the left and right eye images. The results showed that symmetry detection was difficult when the corresponding dots across the symmetry axis were on different frontoparallel or inclined planes. However, this effect was not due to a difference in distance, as the observers could detect symmetry on a slanted surface, where the depth of the two sides of the symmetric axis was different. The threshold was reduced for a hinge configuration where the join of two slanted surfaces coincided with the axis of symmetry. Our result suggests that the detection of two-dimensional (2D) symmetry patterns is subject to the 3D configuration of the scene; and that coplanarity across the symmetry axis and consistency between the 2D pattern and 3D structure are important factors for symmetry detection.
Meshfree natural vibration analysis of 2D structures
NASA Astrophysics Data System (ADS)
Kosta, Tomislav; Tsukanov, Igor
2014-02-01
Determination of resonance frequencies and vibration modes of mechanical structures is one of the most important tasks in the product design procedure. The main goal of this paper is to describe a pioneering application of the solution structure method (SSM) to 2D structural natural vibration analysis problems and investigate the numerical properties of the method. SSM is a meshfree method which enables construction of the solutions to the engineering problems that satisfy exactly all prescribed boundary conditions. This method is capable of using spatial meshes that do not conform to the shape of a geometric model. Instead of using the grid nodes to enforce boundary conditions, it employs distance fields to the geometric boundaries and combines them with the basis functions and prescribed boundary conditions at run time. This defines unprecedented geometric flexibility of the SSM as well as the complete automation of the solution procedure. In the paper we will explain the key points of the SSM as well as investigate the accuracy and convergence of the proposed approach by comparing our results with the ones obtained using analytical methods or traditional finite element analysis. Despite in this paper we are dealing with 2D in-plane vibrations, the proposed approach has a straightforward generalization to model vibrations of 3D structures.
2D Radiative Transfer in Magnetically Confined Structures
NASA Astrophysics Data System (ADS)
Heinzel, P.; Anzer, U.
2003-01-01
Magnetically confined structures in the solar atmosphere exhibit a large complexity in their shapes and physical conditions. As an example, we show the case of so-called magnetic dips in prominences which are in magnetohydrostatic equilibria. For such models we solve 2D non-LTE multilevel problem for hydrogen with PRD in Lyman resonance lines. The iterative technique used is based on the MALI approach with simple diagonal ALO and SC formal solver. To compute the hydrogen ionization balance, the preconditioned MALI equations are linearized with respect to atomic level populations and electron density and solved iteratively using the Newton-Raphson scheme. Two additional problems are addressed: (i) an adequate iteration method for cases when the column-mass scale is used in one of the two dimensions but varies along the other dimension (which has a geometrical scaling); and (ii) a possibility of using AMR (Adaptive Mesh Refinement) algorithms to account for steep 2D gradients of selected variables (temperature, density, etc.).
2D Gridded Surface Data Value-Added Product
Tang, Q; Xie, S
2015-08-30
This report describes the Atmospheric Radiation Measurement (ARM) Best Estimate (ARMBE) 2-dimensional (2D) gridded surface data (ARMBE2DGRID) value-added product. Spatial variability is critically important to many scientific studies, especially those that involve processes of great spatial variations at high temporal frequency (e.g., precipitation, clouds, radiation, etc.). High-density ARM sites deployed at the Southern Great Plains (SGP) allow us to observe the spatial patterns of variables of scientific interests. The upcoming megasite at SGP with its enhanced spatial density will facilitate the studies at even finer scales. Currently, however, data are reported only at individual site locations at different time resolutions for different datastreams. It is difficult for users to locate all the data they need and requires extra effort to synchronize the data. To address these problems, the ARMBE2DGRID value-added product merges key surface measurements at the ARM SGP sites and interpolates the data to a regular 2D grid to facilitate the data application.
Peak width issues with generalised 2D correlation NMR spectroscopy
NASA Astrophysics Data System (ADS)
Kirwan, Gemma M.; Adams, Michael J.
2008-12-01
Two-dimensional spectral correlation analysis is shown to be sensitive to fluctuations in spectral peak width as a function of perturbation variable. This is particularly significant where peak width fluctuations are of similar order of magnitude as the peak width values themselves and where changes in peak width are not random but are, for example, proportional to intensity. In such cases these trends appear in the asynchronous matrix as false peaks that serve to interfere with interpretation of the data. Complex, narrow band spectra such as provided by 1H NMR spectroscopy are demonstrated to be prone to such interference. 2D correlation analysis was applied to a series of NMR spectra corresponding to a commercial wine fermentation, in which the samples collected over a period of several days exhibit dramatic changes in concentration of minor and major components. The interference due to changing peak width effects is eliminated by synthesizing the recorded spectra using a constant peak width value prior to performing 2D correlation analysis.
Reconstruction of a 2D seismic wavefield by seismic gradiometry
NASA Astrophysics Data System (ADS)
Maeda, Takuto; Nishida, Kiwamu; Takagi, Ryota; Obara, Kazushige
2016-12-01
We reconstructed a 2D seismic wavefield and obtained its propagation properties by using the seismic gradiometry method together with dense observations of the Hi-net seismograph network in Japan. The seismic gradiometry method estimates the wave amplitude and its spatial derivative coefficients at any location from a discrete station record by using a Taylor series approximation. From the spatial derivatives in horizontal directions, the properties of a propagating wave packet, including the arrival direction, slowness, geometrical spreading, and radiation pattern can be obtained. In addition, by using spatial derivatives together with free-surface boundary conditions, the 2D vector elastic wavefield can be decomposed into divergence and rotation components. First, as a feasibility test, we performed an analysis with a synthetic seismogram dataset computed by a numerical simulation for a realistic 3D medium and the actual Hi-net station layout. We confirmed that the wave amplitude and its spatial derivatives were very well-reproduced for period bands longer than 25 s. Applications to a real large earthquake showed that the amplitude and phase of the wavefield were well reconstructed, along with slowness vector. The slowness of the reconstructed wavefield showed a clear contrast between body and surface waves and regional non-great-circle-path wave propagation, possibly owing to scattering. Slowness vectors together with divergence and rotation decomposition are expected to be useful for determining constituents of observed wavefields in inhomogeneous media.
2D Quantum Transport Modeling in Nanoscale MOSFETs
NASA Technical Reports Server (NTRS)
Svizhenko, Alexei; Anantram, M. P.; Govindan, T. R.; Biegel, B.
2001-01-01
We have developed physical approximations and computer code capable of realistically simulating 2-D nanoscale transistors, using the non-equilibrium Green's function (NEGF) method. This is the most accurate full quantum model yet applied to 2-D device simulation. Open boundary conditions, oxide tunneling and phase-breaking scattering are treated on an equal footing. Electron bandstructure is treated within the anisotropic effective mass approximation. We present the results of our simulations of MIT 25 and 90 nm "well-tempered" MOSFETs and compare them to those of classical and quantum corrected models. The important feature of quantum model is smaller slope of Id-Vg curve and consequently higher threshold voltage. These results are consistent with 1D Schroedinger-Poisson calculations. The effect of gate length on gate-oxide leakage and subthreshold current has been studied. The shorter gate length device has an order of magnitude smaller leakage current than the longer gate length device without a significant trade-off in on-current.
Mass loss in 2D rotating stellar models
Lovekin, Caterine; Deupree, Bob
2010-10-05
Radiatively driven mass loss is an important factor in the evolution of massive stars . The mass loss rates depend on a number of stellar parameters, including the effective temperature and luminosity. Massive stars are also often rapidly rotating, which affects their structure and evolution. In sufficiently rapidly rotating stars, both the effective temperature and radius vary significantly as a function of latitude, and hence mass loss rates can vary appreciably between the poles and the equator. In this work, we discuss the addition of mass loss to a 2D stellar evolution code (ROTORC) and compare evolution sequences with and without mass loss. Preliminary results indicate that a full 2D calculation of mass loss using the local effective temperature and luminosity can significantly affect the distribution of mass loss in rotating main sequence stars. More mass is lost from the pole than predicted by 1D models, while less mass is lost at the equator. This change in the distribution of mass loss will affect the angular momentum loss, the surface temperature and luminosity, and even the interior structure of the star. After a single mass loss event, these effects are small, but can be expected to accumulate over the course of the main sequence evolution.
2D vibrational properties of epitaxial silicene on Ag(111)
NASA Astrophysics Data System (ADS)
Solonenko, Dmytro; Gordan, Ovidiu D.; Le Lay, Guy; Sahin, Hasan; Cahangirov, Seymur; Zahn, Dietrich R. T.; Vogt, Patrick
2017-03-01
The two-dimensional silicon allotrope, silicene, could spur the development of new and original concepts in Si-based nanotechnology. Up to now silicene can only be epitaxially synthesized on a supporting substrate such as Ag(111). Even though the structural and electronic properties of these epitaxial silicene layers have been intensively studied, very little is known about its vibrational characteristics. Here, we present a detailed study of epitaxial silicene on Ag(111) using in situ Raman spectroscopy, which is one of the most extensively employed experimental techniques to characterize 2D materials, such as graphene, transition metal dichalcogenides, and black phosphorous. The vibrational fingerprint of epitaxial silicene, in contrast to all previous interpretations, is characterized by three distinct phonon modes with A and E symmetries. Both, energies and symmetries of theses modes are confirmed by ab initio theory calculations. The temperature dependent spectral evolution of these modes demonstrates unique thermal properties of epitaxial silicene and a significant electron-phonon coupling. These results unambiguously support the purely two-dimensional character of epitaxial silicene up to about 300 °C, whereupon a 2D-to-3D phase transition takes place. The detailed fingerprint of epitaxial silicene will allow us to identify it in different environments or to study its modifications.
Conformal Laplace superintegrable systems in 2D: polynomial invariant subspaces
NASA Astrophysics Data System (ADS)
Escobar-Ruiz, M. A.; Miller, Willard, Jr.
2016-07-01
2nd-order conformal superintegrable systems in n dimensions are Laplace equations on a manifold with an added scalar potential and 2n-1 independent 2nd order conformal symmetry operators. They encode all the information about Helmholtz (eigenvalue) superintegrable systems in an efficient manner: there is a 1-1 correspondence between Laplace superintegrable systems and Stäckel equivalence classes of Helmholtz superintegrable systems. In this paper we focus on superintegrable systems in two-dimensions, n = 2, where there are 44 Helmholtz systems, corresponding to 12 Laplace systems. For each Laplace equation we determine the possible two-variate polynomial subspaces that are invariant under the action of the Laplace operator, thus leading to families of polynomial eigenfunctions. We also study the behavior of the polynomial invariant subspaces under a Stäckel transform. The principal new results are the details of the polynomial variables and the conditions on parameters of the potential corresponding to polynomial solutions. The hidden gl 3-algebraic structure is exhibited for the exact and quasi-exact systems. For physically meaningful solutions, the orthogonality properties and normalizability of the polynomials are presented as well. Finally, for all Helmholtz superintegrable solvable systems we give a unified construction of one-dimensional (1D) and two-dimensional (2D) quasi-exactly solvable potentials possessing polynomial solutions, and a construction of new 2D PT-symmetric potentials is established.
DNN-state identification of 2D distributed parameter systems
NASA Astrophysics Data System (ADS)
Chairez, I.; Fuentes, R.; Poznyak, A.; Poznyak, T.; Escudero, M.; Viana, L.
2012-02-01
There are many examples in science and engineering which are reduced to a set of partial differential equations (PDEs) through a process of mathematical modelling. Nevertheless there exist many sources of uncertainties around the aforementioned mathematical representation. Moreover, to find exact solutions of those PDEs is not a trivial task especially if the PDE is described in two or more dimensions. It is well known that neural networks can approximate a large set of continuous functions defined on a compact set to an arbitrary accuracy. In this article, a strategy based on the differential neural network (DNN) for the non-parametric identification of a mathematical model described by a class of two-dimensional (2D) PDEs is proposed. The adaptive laws for weights ensure the 'practical stability' of the DNN-trajectories to the parabolic 2D-PDE states. To verify the qualitative behaviour of the suggested methodology, here a non-parametric modelling problem for a distributed parameter plant is analysed.
MESH2D GRID GENERATOR DESIGN AND USE
Flach, G.; Smith, F.
2012-01-20
Mesh2d is a Fortran90 program designed to generate two-dimensional structured grids of the form [x(i),y(i,j)] where [x,y] are grid coordinates identified by indices (i,j). The x(i) coordinates alone can be used to specify a one-dimensional grid. Because the x-coordinates vary only with the i index, a two-dimensional grid is composed in part of straight vertical lines. However, the nominally horizontal y(i,j{sub 0}) coordinates along index i are permitted to undulate or otherwise vary. Mesh2d also assigns an integer material type to each grid cell, mtyp(i,j), in a user-specified manner. The complete grid is specified through three separate input files defining the x(i), y(i,j), and mtyp(i,j) variations. The overall mesh is constructed from grid zones that are typically then subdivided into a collection of smaller grid cells. The grid zones usually correspond to distinct materials or larger-scale geometric shapes. The structured grid zones are identified through uppercase indices (I,J). Subdivision of zonal regions into grid cells can be done uniformly, or nonuniformly using either a polynomial or geometric skewing algorithm. Grid cells may be concentrated backward, forward, or toward both ends. Figure 1 illustrates the above concepts in the context of a simple four zone grid.
Facial biometrics based on 2D vector geometry
NASA Astrophysics Data System (ADS)
Malek, Obaidul; Venetsanopoulos, Anastasios; Androutsos, Dimitrios
2014-05-01
The main challenge of facial biometrics is its robustness and ability to adapt to changes in position orientation, facial expression, and illumination effects. This research addresses the predominant deficiencies in this regard and systematically investigates a facial authentication system in the Euclidean domain. In the proposed method, Euclidean geometry in 2D vector space is being constructed for features extraction and the authentication method. In particular, each assigned point of the candidates' biometric features is considered to be a 2D geometrical coordinate in the Euclidean vector space. Algebraic shapes of the extracted candidate features are also computed and compared. The proposed authentication method is being tested on images from the public "Put Face Database". The performance of the proposed method is evaluated based on Correct Recognition (CRR), False Acceptance (FAR), and False Rejection (FRR) rates. The theoretical foundation of the proposed method along with the experimental results are also presented in this paper. The experimental results demonstrate the effectiveness of the proposed method.
Spectroscopic properties of multilayered gold nanoparticle 2D sheets.
Yoshida, Akihito; Imazu, Keisuke; Li, Xinheng; Okamoto, Koichi; Tamada, Kaoru
2012-12-11
We report the fabrication technique and optical properties of multilayered two-dimensional (2D) gold nanoparticle sheets ("Au nanosheet"). The 2D crystalline monolayer sheet composed of Au nanoparticles shows an absorption peak originating from a localized surface plasmon resonance (LSPR). It was found that the absorption spectra dramatically change when the monolayers are assembled into the multilayers on different substrates (quartz or Au). In the case of the multilayers on Au thin film (d = 200 nm), the LSPR peak is shifted to longer wavelength at the near-IR region by increasing the number of layers. The absorbance also depends on the layer number and shows the nonlinear behavior. On the other hand, the multilayers on quartz substrate show neither such LSPR peak shift nor nonlinear response of absorbance. The layer number dependence on metal surfaces can be interpreted as the combined effects between the near-field coupling of the LSPR and the far-field optics of the stratified metamaterial films, as proposed in our previous study. We also report the spectroscopic properties of hybrid multilayers composed of two kinds of monolayers, i.e., Au nanosheet and Ag nanosheet. The combination of the different metal nanoparticle sheets realizes more flexible plasmonic color tuning.
Asymmetric 2D spatial beam filtering by photonic crystals
NASA Astrophysics Data System (ADS)
Gailevicius, D.; Purlys, V.; Maigyte, L.; Gaizauskas, E.; Peckus, M.; Gadonas, R.; Staliunas, K.
2016-04-01
Spatial filtering techniques are important for improving the spatial quality of light beams. Photonic crystals (PhCs) with a selective spatial (angular) transmittance can also provide spatial filtering with the added benefit transversal symmetries, submillimeter dimensions and monolithic integration in other devices, such as micro-lasers or semiconductor lasers. Workable bandgap PhC configurations require a modulated refractive index with period lengths that are approximately less than the wavelength of radiation. This imposes technical limitations, whereby the available direct laser write (DLW) fabrication techniques are limited in resolution and refractive index depth. If, however, a deflection mechanism is chosen instead, a functional filter PhC can be produced that is operational in the visible wavelength regime. For deflection based PhCs glass is an attractive choice as it is highly stable medium. 2D and 3D PhC filter variations have already been produced on soda-lime glass. However, little is known about how to control the scattering of PhCs when approaching the smallest period values. Here we look into the internal structure of the initially symmetric geometry 2D PhCs and associating it with the resulting transmittance spectra. By varying the DLW fabrication beam parameters and scanning algorithms, we show that such PhCs contain layers that are comprised of semi-tilted structure voxels. We show the appearance of asymmetry can be compensated in order to circumvent some negative effects at the cost of potentially maximum scattering efficiency.
2D Hilbert transform for phase retrieval of speckle fields
NASA Astrophysics Data System (ADS)
Gorsky, M. P.; Ryabyi, P. A.; Ivanskyi, D. I.
2016-09-01
The paper presents principal approaches to diagnosing the structure forming skeleton of the complex optical field. An analysis of optical field singularity algorithms depending on intensity discretization and image resolution has been carried out. An optimal approach is chosen, which allows to bring much closer the solution of the phase problem of localization speckle-field special points. The use of a "window" 2D Hilbert transform for reconstruction of the phase distribution of the intensity of a speckle field is proposed. It is shown that the advantage of this approach consists in the invariance of a phase map to a change of the position of the kernel of transformation and in a possibility to reconstruct the structure-forming elements of the skeleton of an optical field, including singular points and saddle points. We demonstrate the possibility to reconstruct the equi-phase lines within a narrow confidence interval, and introduce an additional algorithm for solving the phase problem for random 2D intensity distributions.
Dynamics of quasi 2D co-rotating vortex merger
NASA Astrophysics Data System (ADS)
Khandekar, Akshay G.
Merger of vortices is examined experimentally to compare the merger of slender parallel vortices generated coincidentally. It is known that like-sign vortices rotate around a common center of circulation and merger between the vortices may occur under certain conditions. This merger is dependent on the strength of the vortex circulation, distance of separation between the centers of the two vortices, ReGamma, and vorticity distribution. Quasi-2D experimental data is examined and merger relations are derived. The 2D experiments conducted in a vortex generator tank uses high aspect ratio rotating paddles. The vortex merger tank generates slender co-rotating vortices and are examined using PIV (Particle Image Velocimetry). Merger characteristics are compared at centerline, 25% span and 5% span for different circulation strengths. Symmetric and asymmetric mergers are studied and it is found that in both cases, the vortex pair rotates around an axis perpendicular to the plane of the vortex pair. Symmetric merger is seen to occur at the center between the two vortices whereas in asymmetric merger the stronger vortex breaks the weaker vortex filaments and continues to follow its path. Wall effects seem to have an effect of vortex braiding and vortex stretching. Closer to the wall, the merger time increases while the merged vortex dissipates faster than at the centerline.
Marginal fluctuations as instantons on M2/D2-branes
NASA Astrophysics Data System (ADS)
Naghdi, M.
2014-03-01
We introduce some (anti-) M/D-branes through turning on the corresponding field strengths of the 11- and 10-dimensional supergravity theories over spaces, where we use and for the internal spaces. Indeed, when we add M2/D2-branes on the same directions with the near horizon branes of the Aharony-Bergman-Jafferis-Maldacena model, all symmetries and supersymmetries are preserved trivially. In this case, we obtain a localized object just in the horizon. This normalizable bulk massless scalar mode is a singlet of and , and it agrees with a marginal boundary operator of the conformal dimension of . However, after performing a special conformal transformation, we see that the solution is localized in the Euclideanized space and is attributable to the included anti-M2/D2-branes, which are also necessary to ensure that there is no back-reaction. The resultant theory now breaks all supersymmetries to , while the other symmetries are so preserved. The dual boundary operator is then set up from the skew-whiffing of the representations and for the supercharges and scalars, respectively, while the fermions remain fixed in of the original theory. Besides, we also address another alternate bulk to boundary matching procedure through turning on one of the gauge fields of the full gauge group along the same lines with a similar situation to the one faced in the AdS/CFT correspondence. The latter approach covers the difficulty already faced with in the bulk-boundary matching procedure for as well.
2D Numerical MHD Models of Solar Explosive Events
NASA Astrophysics Data System (ADS)
Roussev, I.
2001-10-01
Observations of the Sun reveal a great variety of dynamic phenomena interpretable as a manifestation of magnetic reconnection. These range from small-scale 'Explosive events' seen in the 'quiet' Sun, through violent flares observed in active regions. The high degree of complexity of the magnetic field inferred from observations may locally produce a fruitful environment for the process of magnetic reconnection to take place. Explosive events are associated with regions undergoing magnetic flux cancellation. This thesis presents a 2-dimensional (2D) numerical study devoted to explore the idea that the salient spectral signatures seen in explosive events are most probably caused by bi-directional outflow jets as a results of an ongoing magnetic reconnection. In order to provide qualitative results needed for the better physical interpretation of solar explosive events, several models intended to represent a 'quiet' Sun transition of solar explosive events, several models intended to represent a 'quiet' Sun transition region undergoing magnetic reconnection are examined, in both unstratified and gravitationally stratified atmospheres. The magnetic reconnection is initiated in an ad hoc manner, and the dynamic evolution is followed by numerically solving the equations of 2D dissipative magnetohydrodynamics (MHD), including the effects of field-aligned thermal conduction, radiative losses, volumetric heating, and anomalous resistivity.
Preconditioning 2D Integer Data for Fast Convex Hull Computations.
Cadenas, José Oswaldo; Megson, Graham M; Luengo Hendriks, Cris L
2016-01-01
In order to accelerate computing the convex hull on a set of n points, a heuristic procedure is often applied to reduce the number of points to a set of s points, s ≤ n, which also contains the same hull. We present an algorithm to precondition 2D data with integer coordinates bounded by a box of size p × q before building a 2D convex hull, with three distinct advantages. First, we prove that under the condition min(p, q) ≤ n the algorithm executes in time within O(n); second, no explicit sorting of data is required; and third, the reduced set of s points forms a simple polygonal chain and thus can be directly pipelined into an O(n) time convex hull algorithm. This paper empirically evaluates and quantifies the speed up gained by preconditioning a set of points by a method based on the proposed algorithm before using common convex hull algorithms to build the final hull. A speedup factor of at least four is consistently found from experiments on various datasets when the condition min(p, q) ≤ n holds; the smaller the ratio min(p, q)/n is in the dataset, the greater the speedup factor achieved.
Defect Dynamics and Zipping of 2D Colloidal Crystallites
NASA Astrophysics Data System (ADS)
Bowley, Chris; Smullin, Sylvia; Ling, Xinsheng
1998-03-01
We use video microscopy to study defect dynamics in 2D colloidal (charged polystyrene microspheres) crystallites formed at the water-air interface. For small 2D crystallites, one might expect to see free edge dislocations in such small systems since the cost of forming such defects scales logarithmically with the size of the crystallite. But we found that as soon as an edge dislocation forms, it quickly moves to the edge of the crystallite and disappears. This is due to an attraction with an image dislocation outside the edge. As a result, most crystallites are defect-free during most of the time. Interesting things happen when two crystallites try to bind to each other, or zip together. A sharp transition occurs at the shared edge of the two crystallites during the zipping process. This is clearly manifested by a sudden change in the relative velocity between two drifting crystallites or a sudden re-orientation of one of the crystallites relative to the other. This work was supported by the startup funds and a Richard Salomon Faculty Research Award from Brown University.
Influence of Elevation Data Source on 2D Hydraulic Modelling
NASA Astrophysics Data System (ADS)
Bakuła, Krzysztof; StĘpnik, Mateusz; Kurczyński, Zdzisław
2016-08-01
The aim of this paper is to analyse the influence of the source of various elevation data on hydraulic modelling in open channels. In the research, digital terrain models from different datasets were evaluated and used in two-dimensional hydraulic models. The following aerial and satellite elevation data were used to create the representation of terrain-digital terrain model: airborne laser scanning, image matching, elevation data collected in the LPIS, EuroDEM, and ASTER GDEM. From the results of five 2D hydrodynamic models with different input elevation data, the maximum depth and flow velocity of water were derived and compared with the results of the most accurate ALS data. For such an analysis a statistical evaluation and differences between hydraulic modelling results were prepared. The presented research proved the importance of the quality of elevation data in hydraulic modelling and showed that only ALS and photogrammetric data can be the most reliable elevation data source in accurate 2D hydraulic modelling.
2D NMR-spectroscopic screening reveals polyketides in ladybugs.
Deyrup, Stephen T; Eckman, Laura E; McCarthy, Patrick H; Smedley, Scott R; Meinwald, Jerrold; Schroeder, Frank C
2011-06-14
Small molecules of biological origin continue to yield the most promising leads for drug design, but systematic approaches for exploring nature's cache of structural diversity are lacking. Here, we demonstrate the use of 2D NMR spectroscopy to screen a library of biorationally selected insect metabolite samples for partial structures indicating the presence of new chemical entities. This NMR-spectroscopic survey enabled detection of novel compounds in complex metabolite mixtures without prior fractionation or isolation. Our screen led to discovery and subsequent isolation of two families of tricyclic pyrones in Delphastus catalinae, a tiny ladybird beetle that is employed commercially as a biological pest control agent. The D. catalinae pyrones are based on 23-carbon polyketide chains forming 1,11-dioxo-2,6,10-trioxaanthracene and 4,8-dioxo-1,9,13-trioxaanthracene derivatives, representing ring systems not previously found in nature. This study highlights the utility of 2D NMR-spectroscopic screening for exploring nature's structure space and suggests that insect metabolomes remain vastly underexplored.
2D NMR-spectroscopic screening reveals polyketides in ladybugs
Deyrup, Stephen T.; Eckman, Laura E.; McCarthy, Patrick H.; Smedley, Scott R.; Meinwald, Jerrold; Schroeder, Frank C.
2011-01-01
Small molecules of biological origin continue to yield the most promising leads for drug design, but systematic approaches for exploring nature’s cache of structural diversity are lacking. Here, we demonstrate the use of 2D NMR spectroscopy to screen a library of biorationally selected insect metabolite samples for partial structures indicating the presence of new chemical entities. This NMR-spectroscopic survey enabled detection of novel compounds in complex metabolite mixtures without prior fractionation or isolation. Our screen led to discovery and subsequent isolation of two families of tricyclic pyrones in Delphastus catalinae, a tiny ladybird beetle that is employed commercially as a biological pest control agent. The D. catalinae pyrones are based on 23-carbon polyketide chains forming 1,11-dioxo-2,6,10-trioxaanthracene and 4,8-dioxo-1,9,13-trioxaanthracene derivatives, representing ring systems not previously found in nature. This study highlights the utility of 2D NMR-spectroscopic screening for exploring nature’s structure space and suggests that insect metabolomes remain vastly underexplored. PMID:21646540
Electron-Phonon Scattering in Atomically Thin 2D Perovskites.
Guo, Zhi; Wu, Xiaoxi; Zhu, Tong; Zhu, Xiaoyang; Huang, Libai
2016-11-22
Two-dimensional (2D) atomically thin perovskites with strongly bound excitons are highly promising for optoelectronic applications. However, the nature of nonradiative processes that limit the photoluminescence (PL) efficiency remains elusive. Here, we present time-resolved and temperature-dependent PL studies to systematically address the intrinsic exciton relaxation pathways in layered (C4H9NH3)2(CH3NH3)n-1PbnI3n+1 (n = 1, 2, 3) structures. Our results show that scatterings via deformation potential by acoustic and homopolar optical phonons are the main scattering mechanisms for excitons in ultrathin single exfoliated flakes, exhibiting a T(γ) (γ = 1.3 to 1.9) temperature dependence for scattering rates. We attribute the absence of polar optical phonon and defect scattering to efficient screening of Coulomb potential, similar to what has been observed in 3D perovskites. These results establish an understanding of the origins of nonradiative pathways and provide guidelines for optimizing PL efficiencies of atomically thin 2D perovskites.
Interactive 2D to 3D stereoscopic image synthesis
NASA Astrophysics Data System (ADS)
Feldman, Mark H.; Lipton, Lenny
2005-03-01
Advances in stereoscopic display technologies, graphic card devices, and digital imaging algorithms have opened up new possibilities in synthesizing stereoscopic images. The power of today"s DirectX/OpenGL optimized graphics cards together with adapting new and creative imaging tools found in software products such as Adobe Photoshop, provide a powerful environment for converting planar drawings and photographs into stereoscopic images. The basis for such a creative process is the focus of this paper. This article presents a novel technique, which uses advanced imaging features and custom Windows-based software that utilizes the Direct X 9 API to provide the user with an interactive stereo image synthesizer. By creating an accurate and interactive world scene with moveable and flexible depth map altered textured surfaces, perspective stereoscopic cameras with both visible frustums and zero parallax planes, a user can precisely model a virtual three-dimensional representation of a real-world scene. Current versions of Adobe Photoshop provide a creative user with a rich assortment of tools needed to highlight elements of a 2D image, simulate hidden areas, and creatively shape them for a 3D scene representation. The technique described has been implemented as a Photoshop plug-in and thus allows for a seamless transition of these 2D image elements into 3D surfaces, which are subsequently rendered to create stereoscopic views.
Application Perspective of 2D+SCALE Dimension
NASA Astrophysics Data System (ADS)
Karim, H.; Rahman, A. Abdul
2016-09-01
Different applications or users need different abstraction of spatial models, dimensionalities and specification of their datasets due to variations of required analysis and output. Various approaches, data models and data structures are now available to support most current application models in Geographic Information System (GIS). One of the focuses trend in GIS multi-dimensional research community is the implementation of scale dimension with spatial datasets to suit various scale application needs. In this paper, 2D spatial datasets that been scaled up as the third dimension are addressed as 2D+scale (or 3D-scale) dimension. Nowadays, various data structures, data models, approaches, schemas, and formats have been proposed as the best approaches to support variety of applications and dimensionality in 3D topology. However, only a few of them considers the element of scale as their targeted dimension. As the scale dimension is concerned, the implementation approach can be either multi-scale or vario-scale (with any available data structures and formats) depending on application requirements (topology, semantic and function). This paper attempts to discuss on the current and new potential applications which positively could be integrated upon 3D-scale dimension approach. The previous and current works on scale dimension as well as the requirements to be preserved for any given applications, implementation issues and future potential applications forms the major discussion of this paper.
The effects of aging on haptic 2D shape recognition.
Overvliet, Krista E; Wagemans, J; Krampe, Ralf T
2013-12-01
We use the image-mediation model (Klatzky & Lederman, 1987) as a framework to investigate potential sources of adult age differences in the haptic recognition of two-dimensional (2D) shapes. This model states that the low-resolution, temporally sequential, haptic input is translated into a visual image, which is then reperceived through the visual processors, before it is matched against a long-term memory representation and named. In three experiments we tested groups of 12 older (mean age 73.11) and three groups of 12 young adults (mean age 22.80) each. In Experiment 1 we confirm age-related differences in haptic 2D shape recognition, and we show the typical age × complexity interaction. In Experiment 2 we show that if we facilitate the visual translation process, age differences become smaller, but only with simple shapes and not with the more complex everyday objects. In Experiment 3 we target the last step in the model (matching and naming) for complex stimuli. We found that age differences in exploration time were considerably reduced when this component process was facilitated by providing a category name. We conclude that the image-mediation model can explain adult-age differences in haptic recognition, particularly if the role of working memory in forming the transient visual image is considered. Our findings suggest that sensorimotor skills thought to rely on peripheral processes for the most part are critically constrained by age-related changes in central processing capacity in later adulthood.
Predicting non-square 2D dice probabilities
NASA Astrophysics Data System (ADS)
Pender, G. A. T.; Uhrin, M.
2014-07-01
The prediction of the final state probabilities of a general cuboid randomly thrown onto a surface is a problem that naturally arises in the minds of men and women familiar with regular cubic dice and the basic concepts of probability. Indeed, it was considered by Newton in 1664 (Newton 1967 The Mathematical Papers of Issac Newton vol I (Cambridge: Cambridge University Press) pp 60-1). In this paper we make progress on the 2D problem (which can be realized in 3D by considering a long cuboid, or alternatively a rectangular cross-sectioned dreidel). For the two-dimensional case we suggest that the ratio of the probabilities of landing on each of the two sides is given by \\frac{\\sqrt{{{k}^{2}}+{{l}^{2}}}-k}{\\sqrt{{{k}^{2}}+{{l}^{2}}}-l}\\frac{arctan \\frac{l}{k}}{arctan \\frac{k}{l}} where k and l are the lengths of the two sides. We test this theory both experimentally and computationally, and find good agreement between our theory, experimental and computational results. Our theory is known, from its derivation, to be an approximation for particularly bouncy or ‘grippy’ surfaces where the die rolls through many revolutions before settling. On real surfaces we would expect (and we observe) that the true probability ratio for a 2D die is a somewhat closer to unity than predicted by our theory. This problem may also have wider relevance in the testing of physics engines.
NASA Astrophysics Data System (ADS)
Callahan, Patrick Gregory
to describe 3-D shapes using 2-D moment invariants. To do this we characterize 2-D sections of a 3-D microstructure using 2-D moment invariants. The statistical distribution of 2-D moment invariants from the sections are compared to a library of density maps produced from different shapes. The sectioning plane is random so each group of particles produces a statistical distribution of 2-D moments that can represent a microstructure. Then we show three example applications: determination of a 3-D shape by computing the Hellinger distance between moment invariant density maps derived from random 2-D section micrographs and the density map database; automated detection and quantification of rafting in cuboidal microstructures; and quantitative comparison of pairs of microstructures.
Terahertz Spectroscopy of the Bending Vibrations of Acetylene 12C2H2 and 12C2D2
NASA Astrophysics Data System (ADS)
Yu, Shanshan; Drouin, B.; Pearson, J.
2009-12-01
Several fundamental interstellar molecules, e.g., C2H2, CH4 and C3, are completely symmetric molecules and feature no permanent dipole moment and no pure rotation spectrum. As a result they have only previously been observed in the infrared. However, directly observing them with the rest of the molecular column especially when the source is spatially resolved would be very valuable in understanding chemical evolution. Vibrational difference bands provide a means to detect symmetric molecules with microwave precision using terahertz techniques. Herschel, SOFIA and ALMA have the potential to identify a number of vibrational difference bands of light symmetric species. This paper reports laboratory results on 12C2H2 and 12C2D2. Symmetric acetylene isotopologues have two bending modes, the trans bending and the cis bending. Their difference bands are allowed and occur in the microwave, terahertz, and far-infrared wavelengths, with band origins at 3500 GHz for 12C2H2 and 900 GHz for 12C2D2. Twenty 12C2H2 P branch high-J transitions and two hundred and fifty-one 12C2D2 P Q and R branch transitions have been measured in the 0.2 - 1.6 THz region with precision of 50 to 100 kHz. These lines were modeled together with prior data on the pure bending levels. Significantly improved molecular parameters were obtained for 12C2H2 and 12C2D2 with the combined data set, and new frequency and intensity predictions were made to support astrophysics applications. The research was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. S. Y. was supported by an appointment to the NASA Postdoctoral Program, administrated by Oak Ridge Associated Universities through a contract with NASA.
Trache, Tudor; Stöbe, Stephan; Tarr, Adrienn; Pfeiffer, Dietrich; Hagendorff, Andreas
2014-12-01
Comparison of 3D and 2D speckle tracking performed on standard 2D and triplane 2D datasets of normal and pathological left ventricular (LV) wall-motion patterns with a focus on the effect that 3D volume rate (3DVR), image quality and tracking artifacts have on the agreement between 2D and 3D speckle tracking. 37 patients with normal LV function and 18 patients with ischaemic wall-motion abnormalities underwent 2D and 3D echocardiography, followed by offline speckle tracking measurements. The values of 3D global, regional and segmental strain were compared with the standard 2D and triplane 2D strain values. Correlation analysis with the LV ejection fraction (LVEF) was also performed. The 3D and 2D global strain values correlated good in both normally and abnormally contracting hearts, though systematic differences between the two methods were observed. Of the 3D strain parameters, the area strain showed the best correlation with the LVEF. The numerical agreement of 3D and 2D analyses varied significantly with the volume rate and image quality of the 3D datasets. The highest correlation between 2D and 3D peak systolic strain values was found between 3D area and standard 2D longitudinal strain. Regional wall-motion abnormalities were similarly detected by 2D and 3D speckle tracking. 2DST of triplane datasets showed similar results to those of conventional 2D datasets. 2D and 3D speckle tracking similarly detect normal and pathological wall-motion patterns. Limited image quality has a significant impact on the agreement between 3D and 2D numerical strain values.
Preliminary abatement device evaluation: 1D-2D KGM cyclone design
Technology Transfer Automated Retrieval System (TEKTRAN)
Cyclones are predominately used in controlling cotton gin particulate matter (PM) emissions. The most commonly used cyclone designs are the 2D-2D and 1D-3D; however other designs such as the 1D-2D KGM have or are currently being used. A 1D-2D cyclone has a barrel length equal to the barrel diamete...
L-moments and TL-moments of the generalized lambda distribution
Asquith, W.H.
2007-01-01
The 4-parameter generalized lambda distribution (GLD) is a flexible distribution capable of mimicking the shapes of many distributions and data samples including those with heavy tails. The method of L-moments and the recently developed method of trimmed L-moments (TL-moments) are attractive techniques for parameter estimation for heavy-tailed distributions for which the L- and TL-moments have been defined. Analytical solutions for the first five L- and TL-moments in terms of GLD parameters are derived. Unfortunately, numerical methods are needed to compute the parameters from the L- or TL-moments. Algorithms are suggested for parameter estimation. Application of the GLD using both L- and TL-moment parameter estimates from example data is demonstrated, and comparison of the L-moment fit of the 4-parameter kappa distribution is made. A small simulation study of the 98th percentile (far-right tail) is conducted for a heavy-tail GLD with high-outlier contamination. The simulations show, with respect to estimation of the 98th-percent quantile, that TL-moments are less biased (more robost) in the presence of high-outlier contamination. However, the robustness comes at the expense of considerably more sampling variability. ?? 2006 Elsevier B.V. All rights reserved.
Ellis, S W; Rowland, K; Ackland, M J; Rekka, E; Simula, A P; Lennard, M S; Wolf, C R; Tucker, G T
1996-01-01
Cytochrome P-450 2D6 (CYP2D6) is an important human drug-metabolizing enzyme responsible for the oxidation of more than 30 widely used therapeutic agents. The enzymes encoded by the published genomic [Kimura, Umeno, Skoda, Meyer and Gonzalez (1989) Am. J. Hum. Genet. 45, 889-904] and cDNA [Gonzalez, Skoda, Kimura, Umeno, Zanger, Nebert, Gelboin, Hardwick and Meyer (1988) Nature 331, 442-446] sequences of CYP2D6, and presumed to represent wild-type sequences, differ at residue 374 and encode valine (CYP2D6-Val) and methionine (CYP2D6-Met) respectively. The influence of this amino acid difference on cytochrome P-450 expression, ligand binding, catalysis and stereoselective oxidation of metoprolol was investigated by the heterologous expression of the corresponding cDNAs in the yeast Saccharomyces cerevisiae. The level of expression of apo- and holo-protein was similar with each form of CYP2D6 cDNA, and the binding affinities of a series of ligands to CYP2D6-Val and CYP2D6-Met were identical. The enantioselective O-demethylation and alpha-hydroxylation of metoprolol were also similar with each form of CYP2D6, O-demethylation being R-(+)- enantioselective (CYP2D6-Val: R/S, 1.6; CYP2D6-Met: R/S, 1.4), whereas alpha-hydroxylation showed a preference for S-(-)-metoprolol (CYP2D6-Val: R/S, 0.7; CYP2D6-Met: R/S, 0.8). However, although the favoured regiomer overall was O-demethylmetoprolol (ODM), the regioselectivity for O-demethylation of each metoprolol enantiomer was significantly greater for CYP2D6-Val [R-(+)-: ODM/alpha-hydroxymetoprolol (alpha OH), 5.9; S-(-)-: ODM/alpha OH, 2.5) than that observed for CYP2D6-Met [R-(+)-: ODM/alpha OH, 2.2; S-(-)-: ODM/alpha OH, 1.4]. The stereoselective properties of CYP2D6-Val were consistent with those observed for CYP2D6 in human liver microsomes. The difference in the stereoselective properties of CYP2D6-Val and CYP2D6-Met were rationalized with respect to a homology model of the active site of CYP2D6 based on an alignment with
Frequency of undetected CYP2D6 hybrid genes in clinical samples: impact on phenotype prediction.
Black, John Logan; Walker, Denise L; O'Kane, Dennis J; Harmandayan, Maria
2012-01-01
Cytochrome P450 2D6 (CYP2D6) is highly polymorphic. CYP2D6-2D7 hybrid genes can be present in samples containing CYP2D6*4 and CYP2D6*10 alleles. CYP2D7-2D6 hybrid genes can be present in samples with duplication signals and in samples with homozygous genotyping results. The frequency of hybrid genes in clinical samples is unknown. We evaluated 1390 samples for undetected hybrid genes by polymerase chain reaction (PCR) amplification, PCR fragment analysis, TaqMan copy number assays, DNA sequencing, and allele-specific primer extension assay. Of 508 CYP2D6*4-containing samples, 109 (21.5%) harbored CYP2D6*68 + *4-like, whereas 9 (1.8%) harbored CYP2D6*4N + *4-like. Of 209 CYP2D6*10-containing samples, 44 (21.1%) were found to have CYP2D6*36 + *10. Of 332 homozygous samples, 4 (1.2%) harbored a single CYP2D7-2D6 hybrid, and of 341 samples with duplication signals, 25 (7.3%) harbored an undetected CYP2D7-2D6 hybrid. Phenotype before and after accurate genotyping was predicted using a method in clinical use. The presence of hybrid genes had no effect on the phenotype prediction of CYP2D6*4- and CYP2D6*10-containing samples. Four of four (100%) homozygous samples containing a CYP2D7-2D6 gene had a change in predicted phenotype, and 23 of 25 (92%) samples with a duplication signal and a CYP2D7-2D6 gene had a change in predicted phenotype. Four novel genes were identified (CYP2D6*13A1 variants 1 and 2, CYP2D6*13G1, and CYP2D6*13G2), and two novel hybrid tandem structures consisting of CYP2D6*13B + *68×2 + *4-like and CYP2D6*13A1 variant 2 + *1×N were observed.
Boundary effects in welded steel moment connections
NASA Astrophysics Data System (ADS)
Lee, Kyoung-Hyeog
Unprecedented widespread failure of welded moment connections in steel frames caused by the 1994 Northridge and the 1995 Kobe earthquakes have alarmed the engineering communities throughout the world. Welded moment connections in steel frames have been traditionally designed by using the classical beam theory which leads to assumptions that the flanges transfer moment while the web connection primarily resists the shear force. However, this study shows that the magnitude and direction of the principal stresses in the connection region are better approximated by using truss analogy rather than the classical beam theory. Accordingly, both the bending moment and the shear force are transferred across the connection near the beam flanges through diagonal strut action. Thus, the beam flange region of the traditionally designed connection is overloaded. This conclusion explains, to a large extent, the recently observed steel moment connection failures. In this study, detailed finite element analyses were carried out for a representative beam-to-column subassemblage with fully welded connection. The stress distribution in the beam web and flanges in the vicinity of the connection were closely studied. The factors responsible for stress redistribution and concentration were identified by using fundamental principles of mechanics. It was concluded that peak resultant stresses can exceed the values used in simple design calculations by large margins. Using the finite element analysis results and the truss analogy to establish a realistic load path in the connection, a practical and more rational analysis and design procedure was developed. The proposed design procedure and the new connection details were successfully validated through cyclic load testing of a nearly full size specimen. The truss model represented the force transmission around the beam-to-column moment connection region very well. Results of the finite element analyses and the laboratory testing showed
Aerodynamic yawing moment characteristics of bird wings.
Sachs, Gottfried
2005-06-21
The aerodynamic yawing moments due to sideslip are considered for wings of birds. Reference is made to the experience with aircraft wings in order to identify features which are significant for the yawing moment characteristics. Thus, it can be shown that wing sweep, aspect ratio and lift coefficient have a great impact. Focus of the paper is on wing sweep which can considerably increase the yawing moment due to sideslip when compared with unswept wings. There are many birds the wings of which employ sweep. To show the effect of sweep for birds, the aerodynamic characteristics of a gull wing which is considered as a representative example are treated in detail. For this purpose, a sophisticated aerodynamic method is used to compute results of high precision. The yawing moments of the gull wing with respect to the sideslip angle and the lift coefficient are determined. They show a significant level of yaw stability which strongly increases with the lift coefficient. It is particularly high in the lift coefficient region of best gliding flight conditions. In order to make the effect of sweep more perspicuous, a modification of the gull wing employing no sweep is considered for comparison. It turns out that the unswept wing yields yawing moments which are substantially smaller than those of the original gull wing with sweep. Another feature significant for the yawing moment characteristics concerns the fact that sweep is at the outer part of bird wings. By considering the underlying physical mechanism, it is shown that this feature is most important for the efficiency of wing sweep. To sum up, wing sweep provides a primary contribution to the yawing moments. It may be concluded that this is an essential reason why there is sweep in bird wings.
Song, Hong Yan; Wong, Ten It; Sadovoy, Anton; Wu, Lin; Bai, Ping; Deng, Jie; Guo, Shifeng; Wang, Yi; Knoll, Wolfgang; Zhou, Xiaodong
2015-01-07
We designed and fabricated two new nanostructured biosensing chips, with which the sensitive detection of prostate specific antigen (PSA) as low as 100 pg ml(-1) can be achieved, by measuring the plasmon enhanced fluorescence through a conventional dark field microscope. The gold nanostructure arrays, one with gold nanopillars of 140 nm, the other with gold nanoholes of 140 nm, were fabricated via nanoimprinting onto glass substrate, as localized surface plasmon resonance (LSPR) generators to enhance the fluorescent emission of fluorophore, e.g. quantum dot (QD). A sandwich bioassay of capture anti-PSA antibody (cAb)/PSA/detection anti-PSA (dAb) labeled by QD-655 was established on the nanostructures, and the perfect LSPR excitation distance (10-15 nm) between the nanostructure and QD-655 was simulated and controlled by a cleft cAb fragment and streptavidin modified QD. QD was chosen in this study due to its photo stability, broad Stokes shift, and long lifetime. As far as we know, this is the first time that QD is applied for PSA detection on the uniform nanostructured sensing chips based on the LSPR enhanced fluorescence. Due to the miniaturized nanoarray sensing chip (1.8 mm × 1.8 mm), the convenience and specificity for the detection of PSA via the sandwich assay, and the high optical detection sensitivity, the platform has great potential for the development of a portable point-of-care (POC) system for outpatient diagnosis and treatment monitoring.
Interactive initialization of 2D/3D rigid registration
Gong, Ren Hui; Güler, Özgür; Kürklüoglu, Mustafa; Lovejoy, John; Yaniv, Ziv
2013-12-15
Purpose: Registration is one of the key technical components in an image-guided navigation system. A large number of 2D/3D registration algorithms have been previously proposed, but have not been able to transition into clinical practice. The authors identify the primary reason for the lack of adoption with the prerequisite for a sufficiently accurate initial transformation, mean target registration error of about 10 mm or less. In this paper, the authors present two interactive initialization approaches that provide the desired accuracy for x-ray/MR and x-ray/CT registration in the operating room setting. Methods: The authors have developed two interactive registration methods based on visual alignment of a preoperative image, MR, or CT to intraoperative x-rays. In the first approach, the operator uses a gesture based interface to align a volume rendering of the preoperative image to multiple x-rays. The second approach uses a tracked tool available as part of a navigation system. Preoperatively, a virtual replica of the tool is positioned next to the anatomical structures visible in the volumetric data. Intraoperatively, the physical tool is positioned in a similar manner and subsequently used to align a volume rendering to the x-ray images using an augmented reality (AR) approach. Both methods were assessed using three publicly available reference data sets for 2D/3D registration evaluation. Results: In the authors' experiments, the authors show that for x-ray/MR registration, the gesture based method resulted in a mean target registration error (mTRE) of 9.3 ± 5.0 mm with an average interaction time of 146.3 ± 73.0 s, and the AR-based method had mTREs of 7.2 ± 3.2 mm with interaction times of 44 ± 32 s. For x-ray/CT registration, the gesture based method resulted in a mTRE of 7.4 ± 5.0 mm with an average interaction time of 132.1 ± 66.4 s, and the AR-based method had mTREs of 8.3 ± 5.0 mm with interaction times of 58 ± 52 s. Conclusions: Based on the
NASA Astrophysics Data System (ADS)
1998-05-01
illustrates how the appearance of a stellar image at the focal plane is fully controllable. Fast and thorough optical adjustment ensures the best possible optical quality at all times . 9. Image Quality of the VLT This diagram demonstrates that First Light specifications have been fully met and, more impressively, that the actual VLT performance is sometimes already within the more stringent specifications that were expected to be fulfilled only three years from now. The final steps before "First Light" The final, critical testing phase commenced with the installation of the 8.2-m primary (at that time still uncoated) Zerodur mirror and 1.1-m secondary Beryllium mirror during the second half of April. The optics were then gradually brought into position during carefully planned, successive adjustments. Due to the full integration of an advanced, active control system into the VLT concept, this delicate process went amazingly fast, especially when compared to other ground-based telescopes. It included a number of short test exposures in early May, first with the Guide Camera that is used to steer the telescope. Later, some exposures were made with the Test Camera mounted just below the main mirror at the Cassegrain Focus, in a central space inside the mirror cell. It will continue to be used during the upcoming Commissioning Phase, until the first major instruments (FORS and ISAAC) are attached to the UT1, later in 1998. The 8.2-m mirror was successfully aluminized at the Paranal Mirror Coating facility on May 20 and was reattached to the telescope tube the day thereafter, cf. ESO PR Photos 13a-e/98 and ESO PR Photos 14a-i/98. Further test exposures were then made to check the proper functioning of the telescope mechanics, optics and electronics. This has lead up to the moment of First Light , i.e. the time when the telescope is considered able to produce the first, astronomically useful images. Despite an intervening spell of bad atmospheric conditions, this important event
The seismic analyzer: interpreting and illustrating 2D seismic data.
Patel, Daniel; Giertsen, Christopher; Thurmond, John; Gjelberg, John; Gröller, M Eduard
2008-01-01
We present a toolbox for quickly interpreting and illustrating 2D slices of seismic volumetric reflection data. Searching for oil and gas involves creating a structural overview of seismic reflection data to identify hydrocarbon reservoirs. We improve the search of seismic structures by precalculating the horizon structures of the seismic data prior to interpretation. We improve the annotation of seismic structures by applying novel illustrative rendering algorithms tailored to seismic data, such as deformed texturing and line and texture transfer functions. The illustrative rendering results in multi-attribute and scale invariant visualizations where features are represented clearly in both highly zoomed in and zoomed out views. Thumbnail views in combination with interactive appearance control allows for a quick overview of the data before detailed interpretation takes place. These techniques help reduce the work of seismic illustrators and interpreters.
2D ultrasonic elastography with lateral displacement estimation using statistics.
Zhang, Zhihong; Liu, Haolin; Cheng, Yangjie
2014-01-01
Ultrasound elastography is the method of obtaining relative stiffness information of biological tissue, which plays an important role in early diagnosis. Generally, a gradient-based strain imaging algorithm assumes that motion only occurs in an axial direction. However, because tissue has different relative stiffness, the scatter presents lateral motion under high freehand compression. Therefore, errors occur in estimating the cross-correlation phase in the calculation window. A 2D elastography algorithm with lateral displacement estimation using statistics was proposed to reduce errors. The new method was investigated through simulation, and the experiment confirmed that errors introduced by lateral tissue movement have been greatly reduced with no sacrifice of real-time ultrasonic imaging quality.
Effective Hamiltonians of 2D Spin Glass Clusters
NASA Astrophysics Data System (ADS)
Clement, Colin; Liarte, Danilo; Middleton, Alan; Sethna, James
2015-03-01
We have a method for directly identifying the clusters which are thought to dominate the dynamics of spin glasses. We also have a method for generating an effective Hamiltonian treating each cluster as an individual spin. We used these methods on a 2D Ising spin glass with Gaussian bonds. We study these systems by generating samples and correlation functions using a combination of Monte Carlo and high-performance numerically exact Pfaffian methods. With effective cluster Hamiltonians we can calculate the free energy asymmetry of the original clusters and perform a scaling analysis. The scaling exponents found are consistent with Domain-Wall Renormalization Group methods, and probe all length scales. We can also study the flow of these effective Hamiltonians by clustering the clustered spins, and we find that our hard spin Hamiltonians at high temperature retain accurate low-temperature fluctuations when compared to their parent models.
Microwave Imaging with Infrared 2-D Lock-in Amplifier
NASA Astrophysics Data System (ADS)
Chiyo, Noritaka; Arai, Mizuki; Tanaka, Yasuhiro; Nishikata, Atsuhiro; Maeno, Takashi
We have developed a 3-D electromagnetic field measurement system using 2-D lock-in amplifier. This system uses an amplitude modulated electromagnetic wave source to heat a resistive screen. A very small change of temperature on a screen illuminated with the modulated electromagnetic wave is measured using an infrared thermograph camera. In this paper, we attempted to apply our system to microwave imaging. By placing conductor patches in front of the resistive screen and illuminating with microwave, the shape of each conductor was clearly observed as the temperature difference image of the screen. In this way, the conductor pattern inside the non-contact type IC card could be visualized. Moreover, we could observe the temperature difference image reflecting the shape of a Konnyaku (a gelatinous food made from devil's-tonge starch) or a dried fishbone, both as non-conducting material resembling human body. These results proved that our method is applicable to microwave see-through imaging.
A 2D histogram representation of images for pooling
NASA Astrophysics Data System (ADS)
Yu, Xinnan; Zhang, Yu-Jin
2011-03-01
Designing a suitable image representation is one of the most fundamental issues of computer vision. There are three steps in the popular Bag of Words based image representation: feature extraction, coding and pooling. In the final step, current methods make an M x K encoded feature matrix degraded to a K-dimensional vector (histogram), where M is the number of features, and K is the size of the codebook: information is lost dramatically here. In this paper, a novel pooling method, based on 2-D histogram representation, is proposed to retain more information from the encoded image features. This pooling method can be easily incorporated into state-of- the-art computer vision system frameworks. Experiments show that our approach improves current pooling methods, and can achieve satisfactory performance of image classification and image reranking even when using a small codebook and costless linear SVM.
Advecting Procedural Textures for 2D Flow Animation
NASA Technical Reports Server (NTRS)
Kao, David; Pang, Alex; Moran, Pat (Technical Monitor)
2001-01-01
This paper proposes the use of specially generated 3D procedural textures for visualizing steady state 2D flow fields. We use the flow field to advect and animate the texture over time. However, using standard texture advection techniques and arbitrary textures will introduce some undesirable effects such as: (a) expanding texture from a critical source point, (b) streaking pattern from the boundary of the flowfield, (c) crowding of advected textures near an attracting spiral or sink, and (d) absent or lack of textures in some regions of the flow. This paper proposes a number of strategies to solve these problems. We demonstrate how the technique works using both synthetic data and computational fluid dynamics data.
Adaptive superplastic forming using NIKE2D with ISLAND
Engelmann, B.E.; Whirley, R.G.; Raboin, P.J.
1992-07-30
Superplastic forming has emerged as an important manufacturing process for producing near-net-shape parts. The design of a superplastic forming process is more difficult than conventional manufacturing operations, and is less amenable to trial and error approaches. This paper describes a superplastic forming process design capability incorporating nonlinear finite element analysis. The material constraints to allow superplastic behavior are integrated into an external constraint equation which is solved concurrently with the nonlinear finite element equations. The implementation of this approach using the ISLAND solution control language with the nonlinear finite element code NIKE2D is discussed in detail. Superplastic forming process design problems with one and two control parameters are presented as examples.
Tailoring the energy distribution and loss of 2D plasmons
NASA Astrophysics Data System (ADS)
Lin, Xiao; Rivera, Nicholas; López, Josué J.; Kaminer, Ido; Chen, Hongsheng; Soljačić, Marin
2016-10-01
The ability to tailor the energy distribution of plasmons at the nanoscale has many applications in nanophotonics, such as designing plasmon lasers, spasers, and quantum emitters. To this end, we analytically study the energy distribution and the proper field quantization of 2D plasmons with specific examples for graphene plasmons. We find that the portion of the plasmon energy contained inside graphene (energy confinement factor) can exceed 50%, despite graphene being infinitely thin. In fact, this very high energy confinement can make it challenging to tailor the energy distribution of graphene plasmons just by modifying the surrounding dielectric environment or the geometry, such as changing the separation distance between two coupled graphene layers. However, by adopting concepts of parity-time symmetry breaking, we show that tuning the loss in one of the two coupled graphene layers can simultaneously tailor the energy confinement factor and propagation characteristics, causing the phenomenon of loss-induced plasmonic transparency.
CFD code comparison for 2D airfoil flows
NASA Astrophysics Data System (ADS)
Sørensen, Niels N.; Méndez, B.; Muñoz, A.; Sieros, G.; Jost, E.; Lutz, T.; Papadakis, G.; Voutsinas, S.; Barakos, G. N.; Colonia, S.; Baldacchino, D.; Baptista, C.; Ferreira, C.
2016-09-01
The current paper presents the effort, in the EU AVATAR project, to establish the necessary requirements to obtain consistent lift over drag ratios among seven CFD codes. The flow around a 2D airfoil case is studied, for both transitional and fully turbulent conditions at Reynolds numbers of 3 × 106 and 15 × 106. The necessary grid resolution, domain size, and iterative convergence criteria to have consistent results are discussed, and suggestions are given for best practice. For the fully turbulent results four out of seven codes provide consistent results. For the laminar-turbulent transitional results only three out of seven provided results, and the agreement is generally lower than for the fully turbulent case.
2D Monoelemental Arsenene, Antimonene, and Bismuthene: Beyond Black Phosphorus.
Pumera, Martin; Sofer, Zdeněk
2017-02-10
Two-dimensional materials are responsible for changing research in materials science. After graphene and its counterparts, graphane, fluorographene, and others were introduced, waves of renewed interest in 2D binary compounds occurred, such as in metal oxides, transition-metal dichalcogenides (most often represented by MoS2 ), metal oxy/hydroxide borides, and MXenes, to name the most prominent. Recently, interest has turned to two-dimensional monoelemental structures, such as monolayer black phosphorus and, very recently, to monolayer arsenic, antimony, and bismuth. Here, a short overview is provided of the area of exponentially increasing research in arsenene, antimonene, and bismuthene, which belong to the fifth main group of elements, the so-called pnictogens. A short review of historical work is provided, the properties of bulk allotropes of As, Sb, and Bi discussed, and then theoretical and experimental research on mono- and few-layered arsenene, antimonene, and bismuthene addressed, discussing their structures and properties.
Interpretive 2-D treatment of scrape-off-layer plasmas
Umansky, M.; Allen, A.; Daughton, W.
1996-12-31
The width of the scrape-off-layer in a tokamak is determined by cross field transport. In Alcator C-mod the plasma parameters in the scrape-off-layer are measured at upstream and divertor plate locations. We solve a 2-D scrape-off-layer heat conduction equation in the flux geometry (as determined by EFIT) of the C-mod experiment. Bolometric measurements are utilized for the radiative loss term. We use the end wall probe measurements of electron temperature as a boundary condition and the fast scanning probe measurements of upstream temperature are treated as constraints to determine the cross field transport and thermal conductivity. Results are compared with 1-D onion-skin-model predictions.
Model dielectric function for 2D semiconductors including substrate screening
Trolle, Mads L.; Pedersen, Thomas G.; Véniard, Valerie
2017-01-01
Dielectric screening of excitons in 2D semiconductors is known to be a highly non-local effect, which in reciprocal space translates to a strong dependence on momentum transfer q. We present an analytical model dielectric function, including the full non-linear q-dependency, which may be used as an alternative to more numerically taxing ab initio screening functions. By verifying the good agreement between excitonic optical properties calculated using our model dielectric function, and those derived from ab initio methods, we demonstrate the versatility of this approach. Our test systems include: Monolayer hBN, monolayer MoS2, and the surface exciton of a 2 × 1 reconstructed Si(111) surface. Additionally, using our model, we easily take substrate screening effects into account. Hence, we include also a systematic study of the effects of substrate media on the excitonic optical properties of MoS2 and hBN. PMID:28117326
The Anatomy of High-Performance 2D Similarity Calculations
Haque, Imran S.; Pande, Vijay S.
2011-01-01
Similarity measures based on the comparison of dense bit-vectors of two-dimensional chemical features are a dominant method in chemical informatics. For large-scale problems, including compound selection and machine learning, computing the intersection between two dense bit-vectors is the overwhelming bottleneck. We describe efficient implementations of this primitive, as well as example applications, using features of modern CPUs that allow 20-40x performance increases relative to typical code. Specifically, we describe fast methods for population count on modern x86 processors and cache-efficient matrix traversal and leader clustering algorithms that alleviate memory bandwidth bottlenecks in similarity matrix construction and clustering. The speed of our 2D comparison primitives is within a small factor of that obtained on GPUs, and does not require specialized hardware. PMID:21854053
Brillouin light scattering studies of 2D magnonic crystals.
Tacchi, S; Gubbiotti, G; Madami, M; Carlotti, G
2017-02-22
Magnonic crystals, materials with periodic modulation of their magnetic properties, represent the magnetic counterpart of photonic, phononic and plasmonic crystals, and have been largely investigated in recent years because of the possibility of using spin waves as a new means for carrying and processing information over a very large frequency bandwidth. Here, we review recent Brillouin light scattering studies of 2D magnonic crystals consisting of single- and bi-component arrays of interacting magnetic dots or antidot lattices. In particular, we discuss the principal properties of the magnonic band diagram of such systems, with emphasis given to its dependence on both magnetic and the geometrical parameters. Thanks to the possibility of tailoring their band structure by means of several degrees of freedom, planar magnonic crystals offer a good opportunity to design an innovative class of nanoscale microwave devices.
Brillouin light scattering studies of 2D magnonic crystals
NASA Astrophysics Data System (ADS)
Tacchi, S.; Gubbiotti, G.; Madami, M.; Carlotti, G.
2017-02-01
Magnonic crystals, materials with periodic modulation of their magnetic properties, represent the magnetic counterpart of photonic, phononic and plasmonic crystals, and have been largely investigated in recent years because of the possibility of using spin waves as a new means for carrying and processing information over a very large frequency bandwidth. Here, we review recent Brillouin light scattering studies of 2D magnonic crystals consisting of single- and bi-component arrays of interacting magnetic dots or antidot lattices. In particular, we discuss the principal properties of the magnonic band diagram of such systems, with emphasis given to its dependence on both magnetic and the geometrical parameters. Thanks to the possibility of tailoring their band structure by means of several degrees of freedom, planar magnonic crystals offer a good opportunity to design an innovative class of nanoscale microwave devices.
Symmetry detection of auxetic behaviour in 2D frameworks
NASA Astrophysics Data System (ADS)
Mitschke, H.; Schröder-Turk, G. E.; Mecke, K.; Fowler, P. W.; Guest, S. D.
2013-06-01
A symmetry-extended Maxwell treatment of the net mobility of periodic bar-and-joint frameworks is used to derive a sufficient condition for auxetic behaviour of a 2D material. The type of auxetic behaviour that can be detected by symmetry has Poisson's ratio -1, with equal expansion/contraction in all directions, and is here termed equiauxetic. A framework may have a symmetry-detectable equiauxetic mechanism if it belongs to a plane group that includes rotational axes of order n = 6, 4, or 3. If the reducible representation for the net mobility contains mechanisms that preserve full rotational symmetry (A modes), these are equiauxetic. In addition, for n = 6, mechanisms that halve rotational symmetry (B modes) are also equiauxetic.
Discrepant Results in a 2-D Marble Collision
NASA Astrophysics Data System (ADS)
Kalajian, Peter
2013-03-01
Video analysis of 2-D collisions is an excellent way to investigate conservation of linear momentum. The often-desired experimental design goal is to minimize the momentum loss in order to demonstrate the conservation law. An air table with colliding pucks is an ideal medium for this experiment, but such equipment is beyond the budget of many schools. Substituting marbles on a table for air pucks introduces angular momentum and sliding friction so that simple video analysis will demonstrate that linear momentum is not conserved.1,2 Nevertheless, these labs offer students insights into the real-world application of physics. During a recent classroom trial, an unexpected result forced my students to think creatively and critically about what happened in the experiment.
HEXAGONAL ARRAY STRUCTURE FOR 2D NDE APPLICATIONS
Dziewierz, J.; Ramadas, S. N.; Gachagan, A.; O'Leary, R. L.
2010-02-22
This paper describes a combination of simulation and experimentation to evaluate the advantages offered by utilizing a hexagonal shaped array element in a 2D NDE array structure. The active material is a 1-3 connectivity piezoelectric composite structure incorporating triangular shaped pillars--each hexagonal array element comprising six triangular pillars. A combination of PZFlex, COMSOL and Matlab has been used to simulate the behavior of this device microstructure, for operation around 2.25 MHz, with unimodal behavior and low levels of mechanical cross-coupling predicted. Furthermore, the application of hexagonal array elements enables the array aperture to increase by approximately 30%, compared to a conventional orthogonal array matrix and hence will provide enhanced volumetric coverage and SNR. Prototype array configurations demonstrate good corroboration of the theoretically predicted mechanical cross-coupling between adjacent array elements (approx23 dB).
areaDetector: Software for 2-D Detectors in EPICS
Rivers, M.
2011-09-23
areaDetector is a new EPICS module designed to support 2-D detectors. It is modular C++ code that greatly simplifies the task of writing support for a new detector. It also supports plugins, which receive detector data from the driver and process it in some way. Existing plugins perform Region-Of-Interest extraction and analysis, file saving (in netCDF, HDF, TIFF and JPEG formats), color conversion, and export to EPICS records for image display in clients like ImageJ and IDL. Drivers have now been written for many of the detectors commonly used at synchrotron beamlines, including CCDs, pixel array and amorphous silicon detectors, and online image plates.
Robust 2D phase unwrapping based on multiresolution
NASA Astrophysics Data System (ADS)
Davidson, Gordon W.; Bamler, Richard
1996-12-01
An approach to 2D phase unwrapping for SAR interferometry is presented, based on separate steps of coarse phase and fine phase estimation. The coarse phase is constructed from instantaneous frequency estimates obtained using adaptive multiresolution, in which estimation is done of difference frequencies between resolution levels, and the frequency differences are summed over resolution levels such that a conservative phase gradient field is maintained. This allows a smoothed coarse unwrapped phase, which achieves the full terrain height, to be obtained with an unweighted least squares phase construction. The coarse phase is used to remove the bulk of the phase variation of the interferogram, allowing more accurate multilooking, and the resulting fine phase in unwrapped with weighted least squares. The unwrapping approach is verified on simulated interferograms.
TOPAZ2D validation status report, August 1990
Davis, B.
1990-08-01
Analytic solutions to two heat transfer problems were used to partially evaluate the performance TOPAZ, and LLNL finite element heat transfer code. The two benchmark analytic solutions were for: 2D steady state slab, with constant properties, constant uniform temperature boundary conditions on three sides, and constant temperature distribution according to a sine function on the fourth side; 1D transient non-linear, with temperature dependent conductivity and specific heat (varying such that the thermal diffusivity remained constant), constant heat flux on the front face and adiabatic conditions on the other face. The TOPAZ solution converged to the analytic solution in both the transient and the steady state problem. Consistent mass matrix type of analysis yielded best performance for the transient problem, in the late-time response; but notable unnatural anomalies were observed in the early-time temperature response at nodal locations near the front face. 5 refs., 22 figs.
Grid generation for general 2-D regions using hyperbolic equations
NASA Technical Reports Server (NTRS)
Cordova, Jeffrey Q.; Barth, Timothy J.
1988-01-01
A method for applying a hyperbolic grid generation scheme to the construction of meshes in general 2-D regions has been developed. This approach, which follows the theory developed by Steger and Chaussee (1980) and the algorithm outlined by Kinsey and Barth (1984), is based on improving local grid control. This is accomplished by adding an angle control source term to the equations and using a new algorithm for computing the volume source term. These modifications lead to superior methods for fixing the 'local' problems of hyperbolic grid generation, namely, propagation of initial discontinuities and formation of grid shocks (crossing grid lines). More importantly, a method for solving the global problem of constraining the grid with more than one boundary (internal grid generation) has been developed. These algorithms have been implemented in an interactive grid generation program and the results for several geometries are presented and discussed.
2D Quantum Mechanical Study of Nanoscale MOSFETs
NASA Technical Reports Server (NTRS)
Svizhenko, Alexei; Anantram, M. P.; Govindan, T. R.; Biegel, B.; Kwak, Dochan (Technical Monitor)
2000-01-01
With the onset of quantum confinement in the inversion layer in nanoscale MOSFETs, behavior of the resonant level inevitably determines all device characteristics. While most classical device simulators take quantization into account in some simplified manner, the important details of electrostatics are missing. Our work addresses this shortcoming and provides: (a) a framework to quantitatively explore device physics issues such as the source-drain and gate leakage currents, DIBL, and threshold voltage shift due to quantization, and b) a means of benchmarking quantum corrections to semiclassical models (such as density-gradient and quantum-corrected MEDICI). We have developed physical approximations and computer code capable of realistically simulating 2-D nanoscale transistors, using the non-equilibrium Green's function (NEGF) method. This is the most accurate full quantum model yet applied to 2-D device simulation. Open boundary conditions and oxide tunneling are treated on an equal footing. Electrons in the ellipsoids of the conduction band are treated within the anisotropic effective mass approximation. We present the results of our simulations of MIT 25, 50 and 90 nm "well-tempered" MOSFETs and compare them to those of classical and quantum corrected models. The important feature of quantum model is smaller slope of Id-Vg curve and consequently higher threshold voltage. Surprisingly, the self-consistent potential profile shows lower injection barrier in the channel in quantum case. These results are qualitatively consistent with ID Schroedinger-Poisson calculations. The effect of gate length on gate-oxide leakage and subthreshold current has been studied. The shorter gate length device has an order of magnitude smaller current at zero gate bias than the longer gate length device without a significant trade-off in on-current. This should be a device design consideration.
''Super 2D,'' Innovative seismic reprocessing: A case history
Conne, D.K.M.; Bolander, A.G.; MacDonald, R.J.; Strelioff, D.M.
1988-01-01
The ''Super 2D'' processing sequence involves taking a randomly oriented grid of multivintage two-dimensional seismic data and reprocessing to tie the data where required, then interpolating the data set to a regular grid suitable for three-dimensional processing and interpretation. A data set from Alberta, provided by a Canadian oil company, comprises 15 two-dimensional seismic lines collected and processed over a period of 6 years by various contractors. Field conditions, advances in technology, and changing objectives combined to result in a data set that densely sampled a small area, but did not tie in well enough to be interpreted as a whole. The data mistied in time, phase, and frequency, as well as having a problem with multiples in the zone of interest that had been partly attenuated in varying degrees. Therefore, the first objective of reprocessing was to resolve these problems. The authors' current land data processing sequence, which includes frequency balancing followed by source wavelet designature, F/K multiple attenuation, trim statics, and F-X filtering, as well as close attention to statics and velocity control, resolved all the mistie issues and produced a standardized data volume. This data volume was now suitable for the second stage of this sequence (i.e., interpolating to a regular grid and subsequent three-dimensional processing). The volume was three-dimensionally migrated (finite difference), filtered, and scaled. The full range of three-dimensional display and interpretational options, including loading on an interactive system, are now possible. This, along with standardizing the data set and improving the spatial location of events via three-dimensional migration are the key results of the ''Super 2D'' sequence.
Thermocapillary bubble dynamics in a 2D axis swirl domain
NASA Astrophysics Data System (ADS)
Alhendal, Yousuf; Turan, Ali
2014-09-01
The lack of significant buoyancy effects in zero-gravity conditions poses an issue with fluid transfer in a stagnant liquid. In this paper, bubble movement in a stagnant liquid is analysed and presented numerically using a computational fluid dynamics approach. The governing continuum and conservation equations for two-phase flow are solved using the commercial software package Ansys-Fluent v.13. The volume of fluid method is used to track the liquid/gas interface in 2D and 3D domains, which has been found to be a valuable tool for studying the phenomenon of gas-liquid interaction, and the validation results are in reasonable agreement with earlier experimental observations. The flow is driven via Marangoni influence induced by the temperature difference, which in turn drives the bubble from the cold to the hot region. The results indicate that the inherent velocity of bubbles decreases with an increase in Marangoni number; this is in agreement with the results of previous experiments conducted in Kang et al. (Microgravity Sci Technol 20:67-71, 2008). Some three-dimensional simulations will also be performed to compare and examine the results with two-dimensional simulations. The thermocapillary bubble flow in a 2D swirl axisymmetry driven by the rotation of the walls was also carried out for different angular velocities in zero gravity. The bubble migration speed was found to decrease with increasing angular velocity. This occurrence is due to an increase in the pressure gradient between the cylinder's outer wall and the axis of rotation, which forces the lowest pressure region to shift from the sides of the bubble to the axis of rotation. A deformation of the bubble and the formation of the two vortices inside the bubble are also observed. These new and original findings aim to help support research into space applications.
Thermocapillary bubble dynamics in a 2D axis swirl domain
NASA Astrophysics Data System (ADS)
Alhendal, Yousuf; Turan, Ali
2015-04-01
The lack of significant buoyancy effects in zero-gravity conditions poses an issue with fluid transfer in a stagnant liquid. In this paper, bubble movement in a stagnant liquid is analysed and presented numerically using a computational fluid dynamics approach. The governing continuum and conservation equations for two-phase flow are solved using the commercial software package Ansys-Fluent v.13. The volume of fluid method is used to track the liquid/gas interface in 2D and 3D domains, which has been found to be a valuable tool for studying the phenomenon of gas-liquid interaction, and the validation results are in reasonable agreement with earlier experimental observations. The flow is driven via Marangoni influence induced by the temperature difference, which in turn drives the bubble from the cold to the hot region. The results indicate that the inherent velocity of bubbles decreases with an increase in Marangoni number; this is in agreement with the results of previous experiments conducted in Kang et al. (Microgravity Sci Technol 20:67-71, 2008). Some three-dimensional simulations will also be performed to compare and examine the results with two-dimensional simulations. The thermocapillary bubble flow in a 2D swirl axisymmetry driven by the rotation of the walls was also carried out for different angular velocities in zero gravity. The bubble migration speed was found to decrease with increasing angular velocity. This occurrence is due to an increase in the pressure gradient between the cylinder's outer wall and the axis of rotation, which forces the lowest pressure region to shift from the sides of the bubble to the axis of rotation. A deformation of the bubble and the formation of the two vortices inside the bubble are also observed. These new and original findings aim to help support research into space applications.
2D Quantum Transport Modeling in Nanoscale MOSFETs
NASA Technical Reports Server (NTRS)
Svizhenko, Alexei; Anantram, M. P.; Govindan, T. R.; Biegel, Bryan
2001-01-01
With the onset of quantum confinement in the inversion layer in nanoscale MOSFETs, behavior of the resonant level inevitably determines all device characteristics. While most classical device simulators take quantization into account in some simplified manner, the important details of electrostatics are missing. Our work addresses this shortcoming and provides: (a) a framework to quantitatively explore device physics issues such as the source-drain and gate leakage currents, DIBL, and threshold voltage shift due to quantization, and b) a means of benchmarking quantum corrections to semiclassical models (such as density- gradient and quantum-corrected MEDICI). We have developed physical approximations and computer code capable of realistically simulating 2-D nanoscale transistors, using the non-equilibrium Green's function (NEGF) method. This is the most accurate full quantum model yet applied to 2-D device simulation. Open boundary conditions, oxide tunneling and phase-breaking scattering are treated on equal footing. Electrons in the ellipsoids of the conduction band are treated within the anisotropic effective mass approximation. Quantum simulations are focused on MIT 25, 50 and 90 nm "well- tempered" MOSFETs and compared to classical and quantum corrected models. The important feature of quantum model is smaller slope of Id-Vg curve and consequently higher threshold voltage. These results are quantitatively consistent with I D Schroedinger-Poisson calculations. The effect of gate length on gate-oxide leakage and sub-threshold current has been studied. The shorter gate length device has an order of magnitude smaller current at zero gate bias than the longer gate length device without a significant trade-off in on-current. This should be a device design consideration.
E-2D Advanced Hawkeye: primary flight display
NASA Astrophysics Data System (ADS)
Paolillo, Paul W.; Saxena, Ragini; Garruba, Jonathan; Tripathi, Sanjay; Blanchard, Randy
2006-05-01
This paper is a response to the challenge of providing a large area avionics display for the E-2D AHE aircraft. The resulting display design provides a pilot with high-resolution visual information content covering an image area of almost three square feet (Active Area of Samsung display = 33.792cm x 27.0336 cm = 13.304" x 10.643" = 141.596 square inches = 0.983 sq. ft x 3 = 2.95 sq. ft). The avionics display application, design and performance being described is the Primary Flight Display for the E-2D Advanced Hawkeye aircraft. This cockpit display has a screen diagonal size of 17 inches. Three displays, with minimum bezel width, just fit within the available instrument panel area. The significant design constraints of supporting an upgrade installation have been addressed. These constraints include a display image size that is larger than the mounting opening in the instrument panel. This, therefore, requires that the Electromagnetic Interference (EMI) window, LCD panel and backlight all fit within the limited available bezel depth. High brightness and a wide dimming range are supported with a dual mode Cold Cathode Fluorescent Tube (CCFT) and LED backlight. Packaging constraints dictated the use of multiple U shaped fluorescent lamps in a direct view backlight design for a maximum display brightness of 300 foot-Lamberts. The low intensity backlight levels are provided by remote LEDs coupled through a fiber optic mesh. This architecture generates luminous uniformity within a minimum backlight depth. Cross-cockpit viewing is supported with ultra-wide field-of-view performance including contrast and the color stability of an advanced LCD cell design supports. Display system design tradeoffs directed a priority to high optical efficiency for minimum power and weight.
Role of cytochrome P450 2D6 genetic polymorphism in carvedilol hydroxylation in vitro
Wang, Zhe; Wang, Li; Xu, Ren-ai; Zhan, Yun-yun; Huang, Cheng-ke; Dai, Da-peng; Cai, Jian-ping; Hu, Guo-xin
2016-01-01
Cytochrome P450 2D6 (CYP2D6) is a highly polymorphic enzyme that catalyzes the metabolism of a great number of therapeutic drugs. Up to now, >100 allelic variants of CYP2D6 have been reported. Recently, we identified 22 novel variants in the Chinese population in these variants. The purpose of this study was to examine the enzymatic activity of the variants toward the CYP2D6 substrate carvedilol in vitro. The CYP2D6 proteins, including CYP2D6.1 (wild type), CYP2D6.2, CYP2D6.10, and 22 other novel CYP2D6 variants, were expressed from insect microsomes and incubated with carvedilol ranging from 1.0 μM to 50 μM at 37°C for 30 minutes. After termination, the carvedilol metabolites were extracted and detected using ultra-performance liquid chromatography tandem mass-spectrometry. Among the 24 CYP2D6 variants, CYP2D6.92 and CYP2D6.96 were catalytically inactive and the remaining 22 variants exhibited significantly decreased intrinsic clearance values (ranging from ~25% to 95%) compared with CYP2D6.1. The present data in vitro suggest that the newly found variants significantly reduced catalytic activities compared with CYP2D6.1. Given that CYP2D6 protein activities could affect carvedilol plasma levels, these findings are greatly relevant to personalized medicine. PMID:27354764
NASA Astrophysics Data System (ADS)
Michelson, Sara; Bao, Jian-Wen; Grell, Evelyn
2016-04-01
In this study, numerical model simulations of an idealized 2-D squall line are investigated using microphysics budget analysis. Four commonly-used microphysics schemes of various complexity are used in the simulations. Diagnoses of the source and sink terms of the hydrometeor budget equations reveal that the differences related to the assumptions of hydrometeor size-distributions between the schemes lead to the differences in the simulations due to the net effect of various microphysical processes on the interaction between latent heating/evaporative cooling and flow dynamics as the squall line develops. Results from this study also highlight the possibility that the advantage of double-moment formulations can be overshadowed by the uncertainties in the spectral definition of individual hydrometeor categories and spectrum-dependent microphysical processes.
Ferrimagnetism in 2D networks of porphyrin-X and -XO (X=Sc,...,Zn) with acetylene bridges
NASA Astrophysics Data System (ADS)
Wierzbowska, Małgorzata; Sobolewski, Andrzej L.
2016-03-01
Magnetism in 2D networks of the acetylene-bridged transition metal porphyrins M(P)-2(C-C)-2 (denoted P-TM), and oxo-TM-porphyrins OM(P)-2(C-C)-2 (denoted P-TMO), is studied with the density functional theory (DFT) and the self-interaction corrected pseudopotential scheme (pSIC). Addition of oxygen lowers magnetism of P-TMO with respect to the corresponding P-TM for most of the first-half 3d-row TMs. In contrast, binding O with the second-half 3d-row TMs or Sc increases the magnetic moments. Ferrimagnetism is found for the porphyrin networks with the TMs from V to Co and also for these cases with oxygen. This is a long-range effect of the delocalized spin-polarization, extended even to the acetylene bridges.
Multiresolution moment filters: theory and applications.
Sühling, Michael; Arigovindan, Muthuvel; Hunziker, Patrick; Unser, Michael
2004-04-01
We introduce local weighted geometric moments that are computed from an image within a sliding window at multiple scales. When the window function satisfies a two-scale relation, we prove that lower order moments can be computed efficiently at dyadic scales by using a multiresolution wavelet-like algorithm. We show that B-splines are well-suited window functions because, in addition to being refinable, they are positive, symmetric, separable, and very nearly isotropic (Gaussian shape). We present three applications of these multiscale local moments. The first is a feature-extraction method for detecting and characterizing elongated structures in images. The second is a noise-reduction method which can be viewed as a multiscale extension of Savitzky-Golay filtering. The third is a multiscale optical-flow algorithm that uses a local affine model for the motion field, extending the Lucas-Kanade optical-flow method. The results obtained in all cases are promising.
Eight-moment approximation solar wind models
NASA Technical Reports Server (NTRS)
Olsen, Espen Lyngdal; Leer, Egil
1995-01-01
Heat conduction from the corona is important in the solar wind energy budget. Until now all hydrodynamic solar wind models have been using the collisionally dominated gas approximation for the heat conductive flux. Observations of the solar wind show particle distribution functions which deviate significantly from a Maxwellian, and it is clear that the solar wind plasma is far from collisionally dominated. We have developed a numerical model for the solar wind which solves the full equation for the heat conductive flux together with the conservation equations for mass, momentum, and energy. The equations are obtained by taking moments of the Boltzmann equation, using an 8-moment approximation for the distribution function. For low-density solar winds the 8-moment approximation models give results which differ significantly from the results obtained in models assuming the gas to be collisionally dominated. The two models give more or less the same results in high density solar winds.
The moments of inertia of mars
Bills, B.G. )
1989-05-01
The mean moment of inertia of Mars is, at present, very poorly constrained. The generally accepted value of 0.365 MR{sup 2} is obtained by assuming that the observed second degree gravity field can be decomposed into a hydrostatic oblate spheroid and a nonhydrostatic prolate spheroid with an equatorial axis of symmetry. An alternative decomposition is advocated in the present analysis. If the nonhydrostatic component is a maximally triaxial ellipsoid (intermediate moment midway between greatest and least) the hydrostatic component is consistent with a mean moment of 0.345 MR{sup 2}. The plausibility of this decomposition is supported by statistical arguments and comparison with the Earth, Moon and Venus. If confirmed, this new value would have significant implications for the inferred composition and climatic history of Mars. The Mars Observer mission may help resolve this issue.
An online database of nuclear electromagnetic moments
NASA Astrophysics Data System (ADS)
Mertzimekis, T. J.; Stamou, K.; Psaltis, A.
2016-01-01
Measurements of nuclear magnetic dipole and electric quadrupole moments are considered quite important for the understanding of nuclear structure both near and far from the valley of stability. The recent advent of radioactive beams has resulted in a plethora of new, continuously flowing, experimental data on nuclear structure - including nuclear moments - which hinders the information management. A new, dedicated, public and user friendly online database (http://magneticmoments.info) has been created comprising experimental data of nuclear electromagnetic moments. The present database supersedes existing printed compilations, including also non-evaluated series of data and relevant meta-data, while putting strong emphasis on bimonthly updates. The scope, features and extensions of the database are reported.
Manipulating magnetic moments by superconducting currents
NASA Astrophysics Data System (ADS)
Chudnovsky, Eugene M.
2017-03-01
We show that the interaction between a superconducting order parameter and the magnetic moment of an atomic cluster in a two-dimensional s -wave superconductor with Rashba spin-orbit coupling generates magnetic anisotropy that can be stronger or comparable to the magnetic anisotropy due to the crystal field and the shape of the cluster. Transport current through the superconductor produces the effective magnetic field acting on the cluster's magnetic moment. The direction of the effective field depends on the direction of the current, thus allowing one to manipulate the magnetic moment by the superconducting current. Due to the large density of the superconducting current this method of magnetization reversal can be more advantageous at low temperatures than the spin-transfer torque method that requires a large spin-polarized current through a normal metal.
Uehara, Shotaro; Uno, Yasuhiro; Hagihira, Yuya; Murayama, Norie; Shimizu, Makiko; Inoue, Takashi; Sasaki, Erika; Yamazaki, Hiroshi
2015-01-01
1. Although the New World non-human primate, the common marmoset (Callithrix jacchus), is a potentially useful animal model, comprehensive understanding of drug metabolizing enzymes is insufficient. 2. A cDNA encoding a novel cytochrome P450 (P450) 2D8 was identified in marmosets. The amino acid sequence deduced from P450 2D8 cDNA showed a high sequence identity (83-86%) with other primate P450 2Ds. Phylogenetic analysis showed that marmoset P450 2D8 was closely clustered with human P450 2D6, unlike P450 2Ds of miniature pig, dog, rabbit, guinea pig, mouse or rat. 3. Marmoset P450 2D8 mRNA was predominantly expressed in the liver and small intestine among the tissues types analyzed, whereas marmoset P450 2D6 mRNA was expressed predominantly in the liver where P450 2D protein was detected by immunoblotting. 4. By metabolic assays using marmoset P450 2D8 protein heterologously expressed in Escherichia coli, although P450 2D8 exhibits lower catalytic efficiency compared to marmoset and human P450 2D6 enzymes, P450 2D8 mediated O-demethylations of metoprolol and dextromethorphan and bufuralol 1'-hydroxylation. 5. These results suggest that marmoset P450 2D8 (also expressed in the extrahepatic tissues) has potential roles in drug metabolism in a similar manner to those of human and marmoset P450 2D6.
Wang, Danxin; Poi, Ming J; Sun, Xiaochun; Gaedigk, Andrea; Leeder, J Steven; Sadee, Wolfgang
2014-01-01
Cytochrome P450 2D6 (CYP2D6) is involved in the metabolism of 25% of clinically used drugs. Genetic polymorphisms cause substantial variation in CYP2D6 activity and serve as biomarkers guiding drug therapy. However, genotype-phenotype relationships remain ambiguous except for poor metabolizers carrying null alleles, suggesting the presence of yet unknown genetic variants. Searching for regulatory CYP2D6 polymorphisms, we find that a SNP defining the CYP2D6*2 allele, rs16947 [R296C, 17-60% minor allele frequency (MAF)], previously thought to convey normal activity, alters exon 6 splicing, thereby reducing CYP2D6 expression at least 2-fold. In addition, two completely linked SNPs (rs5758550/rs133333, MAF 13-42%) increase CYP2D6 transcription more than 2-fold, located in a distant downstream enhancer region (>100 kb) that interacts with the CYP2D6 promoter. In high linkage disequilibrium (LD) with each other, rs16947 and the enhancer SNPs form haplotypes that affect CYP2D6 enzyme activity in vivo. In a pediatric cohort of 164 individuals, rs16947 alone (minor haplotype frequency 28%) was associated with reduced CYP2D6 metabolic activity (measured as dextromethorphan/metabolite ratios), whereas rs5758550/rs133333 alone (frequency 3%) resulted in increased CYP2D6 activity, while haplotypes containing both rs16947 and rs5758550/rs133333 were similar to the wild-type. Other alleles used in biomarker panels carrying these variants such as CYP2D6*41 require re-evaluation of independent effects on CYP2D6 activity. The occurrence of two regulatory variants of high frequency and in high LD, residing on a long haplotype, highlights the importance of gene architecture, likely shaped by evolutionary selection pressures, in determining activity of encoded proteins.
Oscillating Hadron and Jet Multiplicity Moments
NASA Astrophysics Data System (ADS)
Ochs, W.
2004-01-01
Recently, the moments of multiplicity distributions in e^{+e- annihilation and the ratios Hq (cumulant over factorial moments Kq/Fq) have been determined both for the hadronic final state and for jets at variable resolution. These ratios show an oscillatory behaviour as function of q with strong dependence of the amplitude and length of oscillation on the jet resolution parameter ycut. The recent explanation of this phenomenon based on perturbative QCD calculations is discussed.}
First moments of nucleon generalized parton distributions
Wang, P.; Thomas, A. W.
2010-06-01
We extrapolate the first moments of the generalized parton distributions using heavy baryon chiral perturbation theory. The calculation is based on the one loop level with the finite range regularization. The description of the lattice data is satisfactory, and the extrapolated moments at physical pion mass are consistent with the results obtained with dimensional regularization, although the extrapolation in the momentum transfer to t=0 does show sensitivity to form factor effects, which lie outside the realm of chiral perturbation theory. We discuss the significance of the results in the light of modern experiments as well as QCD inspired models.
Practical method for balancing airplane moments
NASA Technical Reports Server (NTRS)
Hamburger, H
1924-01-01
The present contribution is the sequel to a paper written by Messrs. R. Fuchs, L. Hopf, and H. Hamburger, and proposes to show that the methods therein contained can be practically utilized in computations. Furthermore, the calculations leading up to the diagram of moments for three airplanes, whose performance in war service gave reason for complaint, are analyzed. Finally, it is shown what conclusions can be drawn from the diagram of moments with regard to the defects in these planes and what steps may be taken to remedy them.
Gravitational forces and moments on spacecraft
NASA Technical Reports Server (NTRS)
Kane, T. R.; Likins, P. W.
1975-01-01
The solution of problems of attitude dynamics of spacecraft and the influence of gravitational forces and moments is examined. Arguments are presented based on Newton's law of gravitation, and employing the methods of Newtonian (vectorial) mechanics, with minimal recourse to the classical concepts of potential theory. The necessary ideas were developed and relationships were established to permit the representation of gravitational forces and moments exerted on bodies in space by other bodies, both in terms involving the mass distribution properties of the bodies, and in terms of vector operations on those scalar functions classically described as gravitational potential functions.
Third Zemach moment of the proton
Ian C. Cloet, Gerald A. Miller
2011-01-01
Modern electron scattering experiments have determined the proton electric form factor, G_{Ep}(Q^2), to high precision. We utilize this data, represented by the different form factor parametrizations, to compute the third Zemach moment of the proton charge distribution. We find that existing data rule out a value of the third Zemach moment large enough to explain the current puzzle with the proton charge radius determined from the Lamb shift in muonic hydrogen. This is in contrast with the recent claim of De Rujula [arXiv:1008.3861].
Determination of the Neutron Magnetic Moment
DOE R&D Accomplishments Database
Greene, G. L.; Ramsey, N. F.; Mampe, W.; Pendlebury, J. M.; Smith, K.; Dress, W. B.; Miller, P. D.; Perrin, P.
1981-06-01
The neutron magnetic moment has been measured with an improvement of a factor of 100 over the previous best measurement. Using a magnetic resonance spectrometer of the separated oscillatory field type capable of determining a resonance signal for both neutrons and protons (in flowing H{sub 2}O), we find ..mu..{sub n}/..mu..{sub p} = 0.68497935(17) (0.25 ppM). The neutron magnetic moment can also be expressed without loss of accuracy in a variety of other units.
ELRIS2D: A MATLAB Package for the 2D Inversion of DC Resistivity/IP Data
NASA Astrophysics Data System (ADS)
Akca, Irfan
2016-04-01
ELRIS2D is an open source code written in MATLAB for the two-dimensional inversion of direct current resistivity (DCR) and time domain induced polarization (IP) data. The user interface of the program is designed for functionality and ease of use. All available settings of the program can be reached from the main window. The subsurface is discre-tized using a hybrid mesh generated by the combination of structured and unstructured meshes, which reduces the computational cost of the whole inversion procedure. The inversion routine is based on the smoothness constrained least squares method. In order to verify the program, responses of two test models and field data sets were inverted. The models inverted from the synthetic data sets are consistent with the original test models in both DC resistivity and IP cases. A field data set acquired in an archaeological site is also used for the verification of outcomes of the program in comparison with the excavation results.
Biorthogonal wavelet-based method of moments for electromagnetic scattering
NASA Astrophysics Data System (ADS)
Zhang, Qinke
Wavelet analysis is a technique developed in recent years in mathematics and has found usefulness in signal processing and many other engineering areas. The practical use of wavelets for the solution of partial differential and integral equations in computational electromagnetics has been investigated in this dissertation, with the emphasis on development of biorthogonal wavelet based method of moments for the solution of electric and magnetic field integral equations. The fundamentals and numerical analysis aspects of wavelet theory have been studied. In particular, a family of compactly supported biorthogonal spline wavelet bases on the n-cube (0,1) n has been studied in detail. The wavelet bases were used in this work as a building block to construct biorthogonal wavelet bases on general domain geometry. A specific and practical way of adapting the wavelet bases to certain n- dimensional blocks or elements is proposed based on the domain decomposition and local transformation techniques used in traditional finite element methods and computer aided graphics. The element, with the biorthogonal wavelet base embedded in it, is called a wavelet element in this work. The physical domains which can be treated with this method include general curves, surfaces in 2D and 3D, and 3D volume domains. A two-step mapping is proposed for the purpose of taking full advantage of the zero-moments of wavelets. The wavelet element approach appears to offer several important advantages. It avoids the need of generating very complicated meshes required in traditional finite element based methods, and makes the adaptive analysis easy to implement. A specific implementation procedure for performing adaptive analysis is proposed. The proposed biorthogonal wavelet based method of moments (BWMoM) has been implemented by using object-oriented programming techniques. The main computational issues have been detailed, discussed, and implemented in the whole package. Numerical examples show
Installed Transonic 2D Nozzle Nacelle Boattail Drag Study
NASA Technical Reports Server (NTRS)
Malone, Michael B.; Peavey, Charles C.
1999-01-01
The Transonic Nozzle Boattail Drag Study was initiated in 1995 to develop an understanding of how external nozzle transonic aerodynamics effect airplane performance and how strongly those effects are dependent on nozzle configuration (2D vs. axisymmetric). MDC analyzed the axisymmetric nozzle. Boeing subcontracted Northrop-Grumman to analyze the 2D nozzle. AU participants analyzed the AGARD nozzle as a check-out and validation case. Once the codes were checked out and the gridding resolution necessary for modeling the separated flow in this region determined, the analysis moved to the installed wing/body/nacelle/diverter cases. The boat tail drag validation case was the AGARD B.4 rectangular nozzle. This test case offered both test data and previous CFD analyses for comparison. Results were obtained for test cases B.4.1 (M=0.6) and B.4.2 (M=0.938) and compared very well with the experimental data. Once the validation was complete a CFD grid was constructed for the full Ref. H configuration (wing/body/nacelle/diverter) using a combination of patched and overlapped (Chimera) grids. This was done to ensure that the grid topologies and density would be adequate for the full model. The use of overlapped grids allowed the same grids from the full configuration model to be used for the wing/body alone cases, thus eliminating the risk of grid differences affecting the determination of the installation effects. Once the full configuration model was run and deemed to be suitable the nacelle/diverter grids were removed and the wing/body analysis performed. Reference H wing/body results were completed for M=0.9 (a=0.0, 2.0, 4.0, 6.0 and 8.0), M=1.1 (a=4.0 and 6.0) and M=2.4 (a=0.0, 2.0, 4.4, 6.0 and 8.0). Comparisons of the M=0.9 and M=2.4 cases were made with available wind tunnel data and overall comparisons were good. The axi-inlet/2D nozzle nacelle was analyzed isolated. The isolated nacelle data coupled with the wing/body result enabled the interference effects of the