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Sample records for hybrid zone electronic

  1. Hybrid printed electronics

    NARCIS (Netherlands)

    Koetse, M.; Smits, E.; Rubingh, E.; Teunissen, P.; Kusters, R.; Abbel, R.; Brand, J. van den

    2016-01-01

    Although many electronic functionalities can be realized by printed or organic electronics, short-term marketable products often require robust, reproducible, and nondisturbing technologies. In this chapter we show how hybrid electronics, a combination of printed circuitry, thin-film electronics,

  2. Ants exhibit asymmetric hybridization in a mosaic hybrid zone.

    Science.gov (United States)

    Purcell, Jessica; Zahnd, Sacha; Athanasiades, Anouk; Türler, Rebecca; Chapuisat, Michel; Brelsford, Alan

    2016-10-01

    Research on hybridization between species provides unparalleled insights into the pre- and postzygotic isolating mechanisms that drive speciation. In social organisms, colony-level incompatibilities may provide additional reproductive barriers not present in solitary species, and hybrid zones offer an opportunity to identify these barriers. Here, we use genotyping-by-sequencing to sequence hundreds of markers in a hybrid zone between two socially polymorphic ant species, Formica selysi and Formica cinerea. We characterize the zone, determine the frequency of hybrid workers, infer whether hybrid queens or males are produced and investigate whether hybridization is influenced by colony social organization. We also compare cuticular hydrocarbon profiles and aggression levels between the two species. The hybrid zone exhibits a mosaic structure. The asymmetric distribution of hybrids skewed towards F. cinerea suggests a pattern of unidirectional nuclear gene flow from F. selysi into F. cinerea. The occurrence of backcrossed individuals indicates that hybrid queens and/or males are fertile, and the presence of the F. cinerea mitochondrial haplotype in 97% of hybrids shows that successful F1 hybrids will generally have F. cinerea mothers and F. selysi fathers. We found no evidence that social organization contributes to speciation, because hybrids occur in both single-queen and multiple-queen colonies. Strongly differentiated cuticular hydrocarbon profiles and heightened interspecific aggression further reveal that species recognition cues are both present and perceived. The discovery of fertile hybrids and asymmetrical gene flow is unusual in ants, and this hybrid zone will therefore provide an ideal system with which to investigate speciation in social insects.

  3. Hybrid zone and its genetic analysis: implication for conservation

    Institute of Scientific and Technical Information of China (English)

    ZHENGDong; LIUXue-dong; MAJian-zhang

    2003-01-01

    Hybrid zone is a very critical concept within the evolutionary biology, because it would offer us a better insight to understand the evolutionary role of gene flow and hybridization based on the cline model. This minireview presents an expatia-tion of history perspectives and research developments upon basic concepts including hybrid zones, hybridization, hybrid and its the genetic cline model. Moreover, by figuring out the existing problem around the hybrids within conservative theory and prac-tices, it suggests that the theory of hybrid zone be introduced into conservation biology and it would be provide a broader and more open theoretical background for conservative research and practices.

  4. Estimating the location and shape of hybrid zones

    DEFF Research Database (Denmark)

    Guedj, Benjamin; Guillot, Gilles

    2011-01-01

    We propose a new model to make use of georeferenced genetic data for inferring the location and shape of a hybrid zone. The model output includes the posterior distribution of a parameter that quantifies the width of the hybrid zone. The model proposed is implemented in the GUI and command‐line v...

  5. Bounded hybrid superiority in an avian hybrid zone: effects of mate, diet, and habitat choice.

    Science.gov (United States)

    Good, T P; Ellis, J C; Annett, C A; Pierotti, R

    2000-10-01

    There has been considerable debate in the study of hybrid zones as to whether hybrids may be superior to parental types within the area of contact (bounded hybrid superiority). In birds, naturally occurring hybridization is relatively common, and hybridization within this group always involves mate choice. If hybrids are superior, females choosing heterospecific mates should be expected to show higher fitness under the conditions prevalent in the hybrid zone. Hybrid superiority under these circumstances would reduce reinforcement and thereby help to maintain the hybrid zone. To examine this issue, we studied reproductive performances of hybrids and parental species of gulls (Larus occidentalis and Larus glaucescens) at two colonies within a linear hybrid zone along the west coast of the United States. This hybrid zone contains predominantly gulls of intermediate phenotype. Previous studies indicated that hybrids were superior to one or both parental types, but provided no data on possible mechanisms that underlie this hybrid superiority. Using a hybrid index designed specifically for these species, we identified to phenotype more than 300 individuals associated with nests, including both individual males and females within 73 pairs in the central portion of the hybrid zone and 74 pairs in the northern portion of the hybrid zone. There was little evidence of assortative mating, and what little there was resulted solely because of pairings within intergrades. In the central hybrid zone, females paired with hybrid males produced larger clutches and hatched and fledged more chicks compared with females paired to western gull males. This was a result of heavy predation on eggs in sand habitat, where male western gulls established territories. In contrast, many hybrid males established territories in vegetated cover that was less vulnerable to predation. In the northern part of the hybrid zone, clutch size did not differ among pair categories, however, there were

  6. Particle size analyses of porous silica and hybrid silica chromatographic support particles. Comparison of flow/hyperlayer field-flow fractionation with scanning electron microscopy, electrical sensing zone, and static light scattering.

    Science.gov (United States)

    Xu, Yuehong

    2008-05-16

    Porous silica and hybrid silica chromatographic support particles having particle diameters ranging approximately from 1 microm to 15 microm have been characterized by flow/hyperlayer field-flow fractionation (FFF). The particle size accuracy has been improved significantly in this work by a second-order polynomial calibration. Very good agreement between the FFF data and scanning electron microscopic (SEM) results has been achieved. The effects of particle porosity, pore sizes, and particle sizes on the particle size accuracy in electrical sensing zone (ESZ) analyses have been discussed. It has been demonstrated by computer simulation and experimental measurements that false peaks can be generated in certain particle size regions when the static light scattering (SLS) technique is applied to tightly distributed spherical chromatographic support particles.

  7. Genetic structure in a dynamic baboon hybrid zone corroborates behavioural observations in a hybrid population

    NARCIS (Netherlands)

    Charpentier, M J E; Fontaine, M C; Cherel, E; Renoult, J P; Jenkins, T; Benoit, L; Barthès, N; Alberts, S C; Tung, J

    2012-01-01

    Behaviour and genetic structure are intimately related: mating patterns and patterns of movement between groups or populations influence the movement of genetic variation across the landscape and from one generation to the next. In hybrid zones, the behaviour of the hybridizing taxa can also impact

  8. Hybrid simulation of electron cyclotron resonance heating

    CERN Document Server

    Ropponen, T; Suominen, P; Koponen, T K; Kalvas, T; Koivisto, H

    2008-01-01

    Electron Cyclotron Resonance (ECR) heating is a fundamentally important aspect in understanding the physics of Electron Cyclotron Resonance Ion Sources (ECRIS). Absorption of the radio frequency (RF) microwave power by electron heating in the resonance zone depends on many parameters including frequency and electric field strength of the microwave, magnetic field structure and electron and ion density profiles. ECR absorption has been studied in the past by e.g. modelling electric field behaviour in the resonance zone and its near proximity. This paper introduces a new ECR heating code that implements damping of the microwave power in the vicinity of the resonance zone, utilizes electron density profiles and uses right hand circularly polarized (RHCP) electromagnetic waves to simulate electron heating in ECRIS plasma.

  9. Hybrid simulation of electron cyclotron resonance heating

    Energy Technology Data Exchange (ETDEWEB)

    Ropponen, T. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland)], E-mail: tommi.ropponen@phys.jyu.fi; Tarvainen, O. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Suominen, P. [CERN Geneve 23, CH-1211 (Switzerland); Koponen, T.K. [Department of Physics, University of Jyvaeskylae, Nanoscience Center, P.O. Box 35, FI-40014 (Finland); Kalvas, T.; Koivisto, H. [Department of Physics, University of Jyvaeskylae, P.O. Box 35, FI-40014 (Finland)

    2008-03-11

    Electron Cyclotron Resonance (ECR) heating is a fundamentally important aspect in understanding the physics of Electron Cyclotron Resonance Ion Sources (ECRIS). Absorption of the radio frequency (RF) microwave power by electron heating in the resonance zone depends on many parameters including frequency and electric field strength of the microwave, magnetic field structure and electron and ion density profiles. ECR absorption has been studied in the past by e.g. modelling electric field behaviour in the resonance zone and its near proximity. This paper introduces a new ECR heating code that implements damping of the microwave power in the vicinity of the resonance zone, utilizes electron density profiles and uses right hand circularly polarized (RHCP) electromagnetic waves to simulate electron heating in ECRIS plasma.

  10. NextFlex Flexible Hybrid Electronics Manufacturing

    Science.gov (United States)

    2016-10-01

    and innovators, along with a robust U.S. network of manufacturing nodes, to advance a national flexible hybrid electronics (FHE) manufacturing...methods to scale up today’s FHE laboratory experiments into smart , affordable products. FHE manufacturing en- compasses innovative electronic...The software design tools will encompass multiphysics simulation (e.g., electrical , thermal, mechanical, etc., interactions based on first principles

  11. Spatio-temporal changes in the genetic structure of the Passerina bunting hybrid zone.

    Science.gov (United States)

    Carling, Matthew D; Zuckerberg, Benjamin

    2011-03-01

    Although theoretical models predict that the structure of a hybrid zone can change under a variety of scenarios, only a few empirical studies of hybrid zones have unequivocally demonstrated zone movement. These studies are rare because few data sets exist that include repeated, temporally spaced, samples of the same hybrid zone. We analysed mitochondrial DNA haplotype data from samples separated by 40-45 years from across the Passerina amoena (Lazuli Bunting) and Passerina cyanea (Indigo Bunting) hybrid zone to investigate whether the genetic structure of this zone has changed during that interval. Both cline and generalized linear mixed modelling analyses uncovered a significant narrowing and a substantial westward shift of the Passerina bunting hybrid zone, clearly illustrating hybrid zone movement. The cause of the change may be due to a combination of ecological, demographic and behavioural factors. Our results predict that the width of the hybrid zone will continue to narrow over time, a finding consistent with reinforcement theory.

  12. Hybrid planar free-electron maser in the magnetoresonance regime

    Directory of Open Access Journals (Sweden)

    Vitaliy A. Goryashko

    2009-10-01

    Full Text Available We study the operation regime of a hybrid planar free-electron maser (FEM amplifier near the magnetoresonant value of the uniform longitudinal (guide magnetic field. Using analytical expressions for individual test electron trajectories and normal frequencies of their three-dimensional oscillations in the magnetostatic field of the hybrid planar FEM, an analytical condition of chaotization of motion is established and shown to be given by the Chirikov resonance-overlap criterion applied to the normal undulator and cyclotron frequencies with respect to the coupling induced by the undulator magnetic field. It is also shown analytically that, in spite of the well-known drop for the exact magnetoresonance, the gain attains its maximal value in the zone of regular dynamics slightly above the magnetoresonant value of the guide magnetic field. Under the condition of undulator resonance, it is practically independent of the amplitude of the undulator magnetic field and the wavelength of amplified signal. To account for space-charge effects, we propose a theoretical model of a weakly relativistic FEM, which accommodates not only potential but also rotational parts of the nonradiated electromagnetic field of a moving charged particle. It turns out that the rotational part of nonradiated field diminishes the defocusing influence of the potential part on the beam bunching. Numeric simulation of the nonlinear stage of amplification is fulfilled, taking into consideration adiabatic entrance of the electron beam to the interaction region and initial electron velocity spread. We find that nonradiated field and initial electron velocity spread do not influence essentially the efficiency of hybrid planar FEM amplification if parameters of the beam-microwave interaction correspond to the operational regime in the zone of regular dynamics near the magnetoresonance.

  13. Movement of a Hybrid Zone Between Lineages of the Australian Glass Shrimp (Paratya australiensis).

    Science.gov (United States)

    Wilson, Jeremy D; Schmidt, Daniel J; Hughes, Jane M

    2016-09-01

    In 1993, a population of freshwater glass shrimp (Paratya australiensis) was translocated from Kilcoy Creek to Branch Creek in the Conondale Range, Queensland. Subsequent genetic analysis revealed that the translocated and resident shrimp belonged to different mitochondrial DNA (mtDNA) lineages that were capable of hybridizing. Monitoring of the pools along Branch Creek up until 2002 suggested that the translocated lineage had an advantage in upstream pools and the resident lineage dominated downstream. Differential temperature tolerance and hybridization barriers such as hybrid inviability and mate selection were factors proposed to explain hybrid zone structure. The major objective of this study was to combine nuclear and mtDNA markers to identify the structure of the hybrid zone in 2013 and identify any changes that had occurred since 2002. Specifically, we used genetic data to test for evidence of hybrid zone movement and used the inbreeding coefficient (F IS) to investigate whether mating was random in the contact zone where hybridization barriers could be present. The results revealed that the hybrid zone center has shifted 510 m downstream since 2002. Increased rainfall in the region since 2010 could have facilitated this. Secondly, mating appears significantly nonrandom in the pools where both lineages occur, supporting the existence of partial hybridization barriers. This study reveals a complex and dynamic hybrid zone and exemplifies why multiple temporal studies are necessary to understand hybrid zone structure.

  14. Genome-wide mapping in a house mouse hybrid zone reveals hybrid sterility loci and Dobzhansky-Muller interactions.

    Science.gov (United States)

    Turner, Leslie M; Harr, Bettina

    2014-12-09

    Mapping hybrid defects in contact zones between incipient species can identify genomic regions contributing to reproductive isolation and reveal genetic mechanisms of speciation. The house mouse features a rare combination of sophisticated genetic tools and natural hybrid zones between subspecies. Male hybrids often show reduced fertility, a common reproductive barrier between incipient species. Laboratory crosses have identified sterility loci, but each encompasses hundreds of genes. We map genetic determinants of testis weight and testis gene expression using offspring of mice captured in a hybrid zone between M. musculus musculus and M. m. domesticus. Many generations of admixture enables high-resolution mapping of loci contributing to these sterility-related phenotypes. We identify complex interactions among sterility loci, suggesting multiple, non-independent genetic incompatibilities contribute to barriers to gene flow in the hybrid zone.

  15. Triple Hybrid Energy Harvesting Interface Electronics

    Science.gov (United States)

    Uluşan, H.; Chamanian, S.; Pathirana, W. M. P. R.; Zorlu, Ö.; Muhtaroğlu, A.; Külah, H.

    2016-11-01

    This study presents a novel triple hybrid system that combines simultaneously generated power from thermoelectric (TE), vibration-based electromagnetic (EM) and piezoelectric (PZT) harvesters for a relatively high power supply capability. In the proposed solution each harvesting source utilizes a distinct power management circuit that generates a DC voltage suitable for combining the three parallel supplies. The circuits are designed and implemented in 180 nm standard CMOS technology, and are terminated with a schottky diode to avoid reverse current flow. The harvested AC signal from the EM harvester is rectified with a self-powered AC-DC doubler, which utilizes active diode structures to minimize the forward- bias voltage drop. The PZT interface electronics utilizes a negative voltage converter as the first stage, followed by synchronous power extraction and DC-to-DC conversion through internal switches, and an external inductor. The ultra-low voltage DC power harvested by the TE generator is stepped up through a charge-pump driven by an LC oscillator with fully- integrated center-tapped differential inductors. Test results indicate that hybrid energy harvesting circuit provides more than 1 V output for load resistances higher than 100 kΩ (10 μW) where the stand-alone harvesting circuits are not able to reach 1 V output. This is the first hybrid harvester circuit that simultaneously extracts energy from three independent sources, and delivers a single DC output.

  16. Morphological characterization of a brown lemur hybrid zone (Eulemur rufifrons × E. cinereiceps).

    Science.gov (United States)

    Delmore, Kira E; Louis, Edward E; Johnson, Steig E

    2011-05-01

    Hybridization has recently been identified as a pervasive force in the evolution of primates. In this study, we characterized a hybrid zone between two species of brown lemur (Eulemur rufifrons and E. cinereiceps) in the Andringitra region of southeastern Madagascar using morphological traits. We immobilized animals along a north-south transect (∼80 km), scored them for their degree of hybridity using pelage traits and measured standard morphometric variables. Results from our study suggest that hybridization between E. rufifrons and E. cinereiceps is extensive, with the hybrid zone extending over 42.6 km and being composed mostly of later generation hybrids. We also identified significant variation between ancestral groups in our study: hybrid males exhibited longer tails than both parental species and sexual dimorphism in upper canine height favoring males was documented in E. rufifrons. These patterns could suggest that gene flow between parental and hybrid populations is relatively limited. Finally, significant differences between ancestral groups in relative body mass and skin-fold thickness were absent in our study, indicating that, as measured by these proxies, hybrids are equally as fit as parental forms. Based on these preliminary findings, the Andringitra hybrid zone could conform to the bounded superiority model of hybrid zone stability (i.e., it could be being maintained by selection favoring hybrids within transitional habitats). Accordingly, hybrids in Andringitra may be an unusual case among primates, representing a stable recombinant but distinct lineage. This conclusion has important implications for evolutionary processes within the brown lemur species complex.

  17. Geographic variation in the structure of oak hybrid zones provides insights into the dynamics of speciation.

    Science.gov (United States)

    Zeng, Yan-Fei; Liao, Wan-Jin; Petit, Rémy J; Zhang, Da-Yong

    2011-12-01

    Studying geographic variation in the rate of hybridization between closely related species could provide a useful window on the evolution of reproductive isolation. Reinforcement theory predicts greater prezygotic isolation in areas of prolonged contact between recently diverged species than in areas of recent contact, which implies that old contact zones would be dominated by parental phenotypes with few hybrids (bimodal hybrid zones), whereas recent contact zones would be characterized by hybrid swarms (unimodal hybrid zones). Here, we investigate how the hybrid zones of two closely related Chinese oaks, Quercus mongolica and Q. liaotungensis, are structured geographically using both nuclear and chloroplast markers. We found that populations of Q. liaotungensis located around the Changbai Mountains in Northeast China, an inferred glacial refugium, were introgressed by genes from Q. mongolica, suggesting historical contact between the two species in this region. However, these introgressed populations form sharp bimodal hybrid zones with Q. mongolica. In contrast, populations of Q. liaotungensis located in North China, which show no sign of ancient introgression with Q. mongolica, form unimodal hybrid zones with Q. mongolica. These results are consistent with the hypothesis that selection against hybrids has had sufficient time to reinforce the reproductive barriers between Q. liaotungensis and Q. mongolica in Northeast China but not in North China.

  18. Investigation of (n,γ) reaction in hybrid reactor zones

    Energy Technology Data Exchange (ETDEWEB)

    Guenay, Mehtap [Inoenue Univ., Malatya (Turkey). Physics Dept.

    2014-12-15

    In this study, the fluids were composed with increased mole fractions of a mixture of molten salt: heavy metals 99-95 % Li{sub 20}Sn{sub 80{sup -}}1-5 % SFG-Pu, 99-95 % Li{sub 20}Sn{sub 80{sup -}}1-5 % SFG-PuF{sub 4}, 99-95 % Li{sub 20}Sn{sub 80{sup -}}1-5 % SFG-PuO{sub 2}. In this study, the effect on conversion of each isotope ({sup 238-242}Pu) in spent fuel grade plutonium by (n,γ) reactions was investigated in liquid first wall, blanket and shield zones of the designed hybrid reactor system. Beryllium (Be) is the neutron multiplier by (n,2n) reactions. The Be zone used was 3 cm thick. 9Cr2WVT, a ferritic steel, is used as structural material. Three-dimensional nucleonic calculations were performed by using the most recent versions of the MCNPX-2.7.0 Monte Carlo code and the nuclear data library ENDF/B-VII.0.

  19. Assortative mating and the maintenance of population structure in a natural hybrid zone.

    Science.gov (United States)

    Culumber, Zachary W; Ochoa, Olivia M; Rosenthal, Gil G

    2014-08-01

    Understanding the factors that give rise to natural hybrid zones and govern their dynamics and structure is important to predicting the evolutionary consequences of hybridization. Here we use a combination of multigenerational population genetic data, mating patterns from a natural population, behavioral assays, and mark-recapture data within clinal hybrid zones of the genus Xiphophorus to test the role of assortative mating in maintaining population structure and the potential for ongoing genetic exchange between heterospecifics. Our data demonstrate that population structure is temporally robust and driven largely by assortative mating stemming from precopulatory isolation between pure species. Furthermore, mark-recapture data revealed that rates of migration within the same stream reach are far below the level needed to support population structure. In contrast to many empirical studies of natural hybrid zones, there appeared to be no hybrid male dysfunction or discrimination against hybrid males by pure parental females, and hybrid females mated and associated with pure species and hybrid males at random. Despite strong isolation between pure parentals, hybrids therefore can act as a conduit for genetic exchange between heterospecifics, which has been shown to increase the tempo of evolutionary change. Additionally, our findings highlight the complexity of natural hybrid zone dynamics, demonstrating that sexual and ecological selection together can give rise to patterns that do not fit classical models of hybrid zone evolution.

  20. New evidence for hybrid zones of forest and savanna elephants in Central and West Africa.

    Science.gov (United States)

    Mondol, Samrat; Moltke, Ida; Hart, John; Keigwin, Michael; Brown, Lisa; Stephens, Matthew; Wasser, Samuel K

    2015-12-01

    The African elephant consists of forest and savanna subspecies. Both subspecies are highly endangered due to severe poaching and habitat loss, and knowledge of their population structure is vital to their conservation. Previous studies have demonstrated marked genetic and morphological differences between forest and savanna elephants, and despite extensive sampling, genetic evidence of hybridization between them has been restricted largely to a few hybrids in the Garamba region of northeastern Democratic Republic of Congo (DRC). Here, we present new genetic data on hybridization from previously unsampled areas of Africa. Novel statistical methods applied to these data identify 46 hybrid samples--many more than have been previously identified--only two of which are from the Garamba region. The remaining 44 are from three other geographically distinct locations: a major hybrid zone along the border of the DRC and Uganda, a second potential hybrid zone in Central African Republic and a smaller fraction of hybrids in the Pendjari-Arli complex of West Africa. Most of the hybrids show evidence of interbreeding over more than one generation, demonstrating that hybrids are fertile. Mitochondrial and Y chromosome data demonstrate that the hybridization is bidirectional, involving males and females from both subspecies. We hypothesize that the hybrid zones may have been facilitated by poaching and habitat modification. The localized geography and rarity of hybrid zones, their possible facilitation from human pressures, and the high divergence and genetic distinctness of forest and savanna elephants throughout their ranges, are consistent with calls for separate species classification.

  1. Oscillation of an anuran hybrid zone: morphological evidence spanning 50 years.

    Directory of Open Access Journals (Sweden)

    Jean-Sébastien Roy

    Full Text Available BACKGROUND: The hybrid zone between the primarily forest-dwelling American toad, Anaxyrus americanus, and the prairie-adapted Canadian toad, A. hemiophrys, in southeastern Manitoba is known to have shifted its position during the past 50 years. Hybrid zones are areas of interbreeding between species and their movement across a landscape should reflect their underlying dynamics and environmental change. However, empirical demonstrations of hybrid zone movements over long periods of time are rare. This hybrid zone is dominated by individuals of intermediate morphology and genetic composition. We sought to determine if it had continued to move and if that movement was associated with shifts in habitat, as predicted. METHODOLOGY/PRINCIPLE FINDINGS: We used variation in the toads' most diagnostic morphological feature, the separation between their interorbital cranial crests, to determine the geographic position of the hybrid zone center at four times between 1960 and 2009 using maximum likelihood methods. The hybrid zone center moved west by 38 km over 19 years and then east again by 10 km over the succeeding 29 years. The position of the hybrid zone did not track either the direction or the magnitude of movement of the forest-prairie habitat transition over the same time period. CONCLUSIONS/SIGNIFICANCE: This is the first reported evidence of oscillation in the position of a hybrid zone. The back and forth movement indicates that neither species maintains a selective advantage over the other in the long term. However, the movement of the hybrid zone was not bounded by the breadth of the habitat transition. Its oscillation suggests that the hybrid zone is better described as being elastically tethered to the habitat transition.

  2. SECURED ELECTRONIC VOTING PROTOCOL USING HYBRID CRYPTOSYSTEM

    Directory of Open Access Journals (Sweden)

    KALAICHELVI V

    2013-04-01

    Full Text Available Electronic Voting play a really vital role in the democracy of our life. In this paper, we propose an electronic voting protocol. Our scheme does not require a special voting channel and communication can occur entirely over the current Internet. This method integrates the Internet convenience and cryptology. In the existing protocol the Tallier has to wait until the decryption key is received from the voter. So it will consume lot of time. But, the proposed protocol is based on the hybrid cryptosystem. In this, the ballot is encrypted using faster secret key algorithm and the digital envelope is encrypted using Tallier’s public key. So, the Tallier will decrypt the digital envelope using his own private key to get the secret key and then the encrypted ballot is decrypted using that secret key. So, comparatively the proposed protocol consumes less time. This paper also analyzes the various security issues involved in an electronic voting like security, privacy, authentication, anonymous, uniqueness, accuracy, fairness, efficiency and uncoercibility.

  3. Heterogeneous genome divergence, differential introgression, and the origin and structure of hybrid zones.

    Science.gov (United States)

    Harrison, Richard G; Larson, Erica L

    2016-06-01

    Hybrid zones have been promoted as windows on the evolutionary process and as laboratories for studying divergence and speciation. Patterns of divergence between hybridizing species can now be characterized on a genomewide scale, and recent genome scans have focused on the presence of 'islands' of divergence. Patterns of heterogeneous genomic divergence may reflect differential introgression following secondary contact and provide insights into which genome regions contribute to local adaptation, hybrid unfitness and positive assortative mating. However, heterogeneous genome divergence can also arise in the absence of any gene flow, as a result of variation in selection and recombination across the genome. We suggest that to understand hybrid zone origins and dynamics, it is essential to distinguish between genome regions that are divergent between pure parental populations and regions that show restricted introgression where these populations interact in hybrid zones. The latter, more so than the former, reveal the likely genetic architecture of reproductive isolation. Mosaic hybrid zones, because of their complex structure and multiple contacts, are particularly good subjects for distinguishing primary intergradation from secondary contact. Comparisons among independent hybrid zones or transects that involve the 'same' species pair can also help to distinguish between divergence with gene flow and secondary contact. However, data from replicate hybrid zones or replicate transects do not reveal consistent patterns; in a few cases, patterns of introgression are similar across independent transects, but for many taxa, there is distinct lack of concordance, presumably due to variation in environmental context and/or variation in the genetics of the interacting populations.

  4. Quantifying the spatiotemporal dynamics in a chorus frog (Pseudacris) hybrid zone over 30 years.

    Science.gov (United States)

    Engebretsen, Kristin N; Barrow, Lisa N; Rittmeyer, Eric N; Brown, Jeremy M; Moriarty Lemmon, Emily

    2016-07-01

    Although theory suggests that hybrid zones can move or change structure over time, studies supported by direct empirical evidence for these changes are relatively limited. We present a spatiotemporal genetic study of a hybrid zone between Pseudacris nigrita and P. fouquettei across the Pearl River between Louisiana and Mississippi. This hybrid zone was initially characterized in 1980 as a narrow and steep "tension zone," in which hybrid populations were inferior to parentals and were maintained through a balance between selection and dispersal. We reanalyzed historical tissue samples and compared them to samples of recently collected individuals using microsatellites. Clinal analyses indicate that the cline has not shifted in roughly 30 years but has widened significantly. Anthropogenic and natural changes may have affected selective pressure or dispersal, and our results suggest that the zone may no longer best be described as a tension zone. To the best of our knowledge, this study provides the first evidence of significant widening of a hybrid cline but stasis of its center. Continued empirical study of dynamic hybrid zones will provide insight into the forces shaping their structure and the evolutionary potential they possess for the elimination or generation of species.

  5. Plant hybrid zones affect biodiversity: Tools for a genetic-based understanding of community structure

    Energy Technology Data Exchange (ETDEWEB)

    Whitham, T.G.; Martinsen, G.D.; Keim, P. [Northern Arizona Univ., Flagstaff, AZ (United States); Floate, K.D. [Agriculture and Agri-Food Canada, Lethbridge, Alberta (Canada); Dungey, H.S. [Univ. of Tasmania, Hobart, Tasmania (Australia)]|[Queensland Forest Research Inst., Gympie, Queensland (Australia); Potts, B.M. [Univ. of Tasmania, Hobart, Tasmania (Australia)

    1999-03-01

    Plant hybrid zones are dynamic centers of ecological and evolutionary processes for plants and their associated communities. Studies in the wild and in gardens with synthetic crosses showed that hybrid eucalypts supports the greatest species richness and abundances of insect and fungal taxa. In an updated review of 152 case studies of taxa associated with diverse hybridizing systems, there were 43 (28%) cases of hybrids being more susceptible than their parent species, 7 (5%) resistant, 35 (23%) additive, 35 (23%) dominant, and 32 (21%) showed no response to hybridization. Thus, most taxa respond to hybrids in ways that result in equal or greater abundance, and hybrids tend to accumulate the taxa of their parent species. These studies suggest that genetic-based plant traits affect the distribution of many species and that the variation in hybrids can be used as tools to examine the genetic components of community structure and biodiversity.

  6. Habitat differentiation in a narrow hybrid zone between diploid and tetraploid Anthoxanthum alpinum

    OpenAIRE

    Felber-Girard, M.; Felber, François; Buttler, Alexandre

    2008-01-01

    Populations of diploid and autotetraploid Anthoxanthum alpinum A. & D. Löve formed a narrow hybrid zone in a study area in the Swiss Prealps. Detailed vegetation analyses were performed along transects in several contact zones between the two cytotypes. The vegetation differed according to the position in the hybrid zone. When considering the hybrid zone as a whole, and for one transect that was analysed in detail, there was strong evidence for habitat segregation between the cytotypes. Veget...

  7. Ongoing movement of the hermit warbler X Townsend's warbler hybrid zone.

    Directory of Open Access Journals (Sweden)

    Meade Krosby

    Full Text Available BACKGROUND: Movements of hybrid zones - areas of overlap and interbreeding between species - are difficult to document empirically. This is true because moving hybrid zones are expected to be rare, and because movement may proceed too slowly to be measured directly. Townsend's warblers (Dendroica townsendi hybridize with hermit warblers (D. occidentalis where their ranges overlap in Washington and Oregon. Previous morphological, behavioral, and genetic studies of this hybrid zone suggest that it has been steadily moving into the geographical range of hermit warblers, with the more aggressive Townsend's warblers replacing hermit warblers along ∼2000 km of the Pacific coast of Canada and Alaska. Ongoing movement of the zone, however, has yet to be empirically demonstrated. METHODOLOGY/PRINCIPAL FINDINGS: We compared recently sampled hybrid zone specimens to those collected 10-20 years earlier, to test directly the long-standing hypothesis of hybrid zone movement between these species. Newly sampled specimens were more Townsend's-like than historical specimens, consistent with ongoing movement of the zone into the geographical range of hermit warblers. CONCLUSIONS/SIGNIFICANCE: While movement of a hybrid zone may be explained by several possible mechanisms, in this case a wealth of existing evidence suggests that movement is being driven by the competitive displacement of hermit warblers by Townsend's warblers. That no ecological differences have been found between these species, and that replacement of hermit warblers by Townsend's warblers is proceeding downward in latitude and elevation - opposite the directions of range shifts predicted by recent climate change - further support that this movement is not being driven by alternative environmental factors. If the mechanism of competitive displacement is correct, whether this process will ultimately lead to the extinction of hermit warblers will depend on the continued maintenance of the

  8. Asymmetrical gene flow in a hybrid zone of Hawaiian Schiedea (Caryophyllaceae species with contrasting mating systems.

    Directory of Open Access Journals (Sweden)

    Lisa E Wallace

    Full Text Available Asymmetrical gene flow, which has frequently been documented in naturally occurring hybrid zones, can result from various genetic and demographic factors. Understanding these factors is important for determining the ecological conditions that permitted hybridization and the evolutionary potential inherent in hybrids. Here, we characterized morphological, nuclear, and chloroplast variation in a putative hybrid zone between Schiedea menziesii and S. salicaria, endemic Hawaiian species with contrasting breeding systems. Schiedea menziesii is hermaphroditic with moderate selfing; S. salicaria is gynodioecious and wind-pollinated, with partially selfing hermaphrodites and largely outcrossed females. We tested three hypotheses: 1 putative hybrids were derived from natural crosses between S. menziesii and S. salicaria, 2 gene flow via pollen is unidirectional from S. salicaria to S. menziesii and 3 in the hybrid zone, traits associated with wind pollination would be favored as a result of pollen-swamping by S. salicaria. Schiedea menziesii and S. salicaria have distinct morphologies and chloroplast genomes but are less differentiated at the nuclear loci. Hybrids are most similar to S. menziesii at chloroplast loci, exhibit nuclear allele frequencies in common with both parental species, and resemble S. salicaria in pollen production and pollen size, traits important to wind pollination. Additionally, unlike S. menziesii, the hybrid zone contains many females, suggesting that the nuclear gene responsible for male sterility in S. salicaria has been transferred to hybrid plants. Continued selection of nuclear genes in the hybrid zone may result in a population that resembles S. salicaria, but retains chloroplast lineage(s of S. menziesii.

  9. Reductive dechlorination of trichloroethene DNAPL source zones: source zone architecture versus electron donor availability

    Science.gov (United States)

    Krol, M.; Kokkinaki, A.; Sleep, B.

    2014-12-01

    The persistence of dense-non-aqueous-phase liquids (DNAPLs) in the subsurface has led practitioners and regulatory agencies to turn towards low-maintenance, low-cost remediation methods. Biological degradation has been suggested as a possible solution, based on the well-proven ability of certain microbial species to break down dissolved chlorinated ethenes under favorable conditions. However, the biodegradation of pure phase chlorinated ethenes is subject to additional constraints: the continuous release of electron acceptor at a rate governed by mass transfer kinetics, and the temporal and spatial heterogeneity of DNAPL source zones which leads to spatially and temporally variable availability of the reactants for reductive dechlorination. In this work, we investigate the relationship between various DNAPL source zone characteristics and reaction kinetics using COMPSIM, a multiphase groundwater model that considers non-equilibrium mass transfer and Monod-type kinetics for reductive dechlorination. Numerical simulations are performed for simple, homogeneous trichloroethene DNAPL source zones to demonstrate the effect of single source zone characteristics, as well as for larger, more realistic heterogeneous source zones. It is shown that source zone size, and mass transfer kinetics may have a decisive effect on the predicted bio-enhancement. Finally, we evaluate the performance of DNAPL bioremediation for realistic, thermodynamically constrained, concentrations of electron donor. Our results indicate that the latter may be the most important limitation for the success of DNAPL bioremediation, leading to reduced bio-enhancement and, in many cases, comparable performance with water flooding.

  10. Staggered Chromosomal Hybrid Zones in the House Mouse: Relevance to Reticulate Evolution and Speciation

    Directory of Open Access Journals (Sweden)

    İslam Gündüz

    2010-07-01

    Full Text Available In the house mouse there are numerous chromosomal races distinguished by different combinations of metacentric chromosomes. These may come into contact with each other and with the ancestral all-acrocentric race, and form hybrid zones. The chromosomal clines that make up these hybrid zones may be coincident or separated from each other (staggered. Such staggered hybrid zones are interesting because they may include populations of individuals homozygous for a mix of features of the hybridising races. We review the characteristics of four staggered hybrid zones in the house mouse and discuss whether they are examples of primary or secondary contact and whether they represent reticulate evolution or not. However, the most important aspect of staggered hybrid zones is that the homozygous populations within the zones have the potential to expand their distributions and become new races (a process termed ‘zonal raciation’. In this way they can add to the total ‘stock’ of chromosomal races in the species concerned. Speciation is an infrequent phenomenon that may involve an unusual set of circumstances. Each one of the products of zonal raciation has the potential to become a new species and by having more races increases the chance of a speciation event.

  11. Mixed protonic and electronic conductors hybrid oxide synaptic transistors

    Science.gov (United States)

    Fu, Yang Ming; Zhu, Li Qiang; Wen, Juan; Xiao, Hui; Liu, Rui

    2017-05-01

    Mixed ionic and electronic conductor hybrid devices have attracted widespread attention in the field of brain-inspired neuromorphic systems. Here, mixed protonic and electronic conductor (MPEC) hybrid indium-tungsten-oxide (IWO) synaptic transistors gated by nanogranular phosphorosilicate glass (PSG) based electrolytes were obtained. Unique field-configurable proton self-modulation behaviors were observed on the MPEC hybrid transistor with extremely strong interfacial electric-double-layer effects. Temporally coupled synaptic plasticities were demonstrated on the MPEC hybrid IWO synaptic transistor, including depolarization/hyperpolarization, synaptic facilitation and depression, facilitation-stead/depression-stead behaviors, spiking rate dependent plasticity, and high-pass/low-pass synaptic filtering behaviors. MPEC hybrid synaptic transistors may find potential applications in neuron-inspired platforms.

  12. Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

    Directory of Open Access Journals (Sweden)

    Jared M LeBoldus

    Full Text Available Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis and (or to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or hybridization ('phenological sink' hypothesis. We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined] zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal

  13. Testing the 'hybrid susceptibility' and 'phenological sink' hypotheses using the P. balsamifera - P. deltoides hybrid zone and septoria leaf spot [Septoria musiva].

    Science.gov (United States)

    LeBoldus, Jared M; Isabel, Nathalie; Floate, Kevin D; Blenis, Peter; Thomas, Barb R

    2013-01-01

    Hybrid genotypes that arise between plant species frequently have increased susceptibility to arthropod pests and fungal pathogens. This pattern has been attributed to the breakdown of plant defenses ('Hybrid susceptibility' hypothesis) and (or) to extended periods of susceptibility attributed to plant phenologies in zones of species overlap and (or) hybridization ('phenological sink' hypothesis). We examined these hypotheses by assessing the susceptibility of parental and hybrid Populus host genotypes to a leaf spot disease caused by the fungal pathogen Septoria musiva. For this purpose, 214 genotypes were obtained from morphologically pure zones of P. balsamifera and P. deltoides, and from an intervening zone of overlap and hybridization on the drainage of the Red Deer River, Alberta, Canada. Genotypes were identified as P. balsamifera, P. deltoides, or hybrid using a suite of 27 species-specific SNP markers. Initially the genetic structure of the hybrid zone was characterized with 27.7% of trees classified as admixed individuals. To test the hybrid susceptibility hypothesis, a subset of 52 genotypes was inoculated with four isolates of S. musiva. Levels of susceptibility were P. balsamifera > F1 hybrid > P. deltoides. A further 53 genotypes were grown in a common garden to assess the effect of genotype on variation in leaf phenology. Leaf phenology was more variable within the category of hybrid genotypes than within categories of either parental species. Leaf phenology was also more variable for the category of trees originating in the hybrid (P. balsamifera - P. deltoides [hybrid and parental genotypes combined]) zone than in adjacent pure zones of the parental species. The results from the inoculation experiment support the hybrid intermediacy hypothesis. The results from the common garden experiment support the 'phenological sink' hypothesis. These findings have greatly increased our understanding of the epidemiology and ecology of fungal pathogens in plant

  14. Clinal variation in a brown lemur (Eulemur spp.) hybrid zone: combining morphological, genetic and climatic data to examine stability.

    Science.gov (United States)

    Delmore, K E; Brenneman, R A; Lei, R; Bailey, C A; Brelsford, A; Louis, E E; Johnson, S E

    2013-08-01

    Studies of hybrid zones can inform our understanding of reproductive isolation and speciation. Two species of brown lemur (Eulemur rufifrons and E. cinereiceps) form an apparently stable hybrid zone in the Andringitra region of southeastern Madagascar. The aim of this study was to identify factors that contribute to this stability. We sampled animals at 11 sites along a 90-km transect through the hybrid zone and examined variation in 26 microsatellites, the D-loop region of mitochondrial DNA, six pelage and nine morphological traits; we also included samples collected in more distant allopatric sites. Clines in these traits were noncoincident, and there was no increase in either inbreeding coefficients or linkage disequilibrium at the centre of the zone. These results could suggest that the hybrid zone is maintained by weak selection against hybrids, conforming to either the tension zone or geographical selection-gradient model. However, a closer examination of clines in pelage and microsatellites indicates that these clines are not sigmoid or stepped in shape but instead plateau at their centre. Sites within the hybrid zone also occur in a distinct habitat, characterized by greater seasonality in precipitation and lower seasonality in temperature. Together, these findings suggest that the hybrid zone may follow the bounded superiority model, with exogenous selection favouring hybrids within the transitional zone. These findings are noteworthy, as examples supporting the bounded superiority model are rare and may indicate a process of ecologically driven speciation without geographical isolation.

  15. Technique for Measuring Hybrid Electronic Component Reliability

    Energy Technology Data Exchange (ETDEWEB)

    Green, C.C.; Hernandez, C.L.; Hosking, F.M.; Robinson, D.; Rutherford, B.; Uribe, F.

    1999-01-01

    Materials compatibility studies of aged, engineered materials and hardware are critical to understanding and predicting component reliability, particularly for systems with extended stockpile life requirements. Nondestructive testing capabilities for component reliability would significantly enhance lifetime predictions. For example, if the detection of crack propagation through a solder joint can be demonstrated, this technique could be used to develop baseline information to statistically determine solder joint lifelengths. This report will investigate high frequency signal response techniques for nondestructively evaluating the electrical behavior of thick film hybrid transmission lines.

  16. Hybrid electronics and electrochemistry with conjugated polymers.

    Science.gov (United States)

    Inganäs, Olle

    2010-07-01

    In this critical review, we discuss the history and development of polymer devices wherein manipulation of the electronic conductivity by electrochemical redox processes in a conjugated polymer is used to form new functions. The devices employed are an electrochemical transistor, an electrolyte-gated field-effect transistor and light-emitting electrochemical cells, all of which combine doping/undoping of a conjugated polymer with modification of electronic transport (130 references).

  17. Differential pollinator effectiveness and importance in a milkweed (Asclepias, Apocynaceae) hybrid zone.

    Science.gov (United States)

    Stoepler, Teresa M; Edge, Andrea; Steel, Anna; O'Quinn, Robin L; Fishbein, Mark

    2012-03-01

    Exceptions to the ideal of complete reproductive isolation between species are commonly encountered in diverse plant, animal, and fungal groups, but often the causative ecological processes are poorly understood. In flowering plants, the outcome of hybridization depends in part on the effectiveness of pollinators in interspecific pollen transport. In the Asclepias exaltata and A. syriaca (Apocynaceae) hybrid zone in Shenandoah National Park, Virginia, extensive introgression has been documented. The objectives of this study were to (1) determine the extent of pollinator overlap among A. exaltata, A. syriaca, and their hybrids and (2) identify the insect taxa responsible for hybridization and introgression. We observed focal plants of parental species and hybrids to measure visitation rate, visit duration, and per-visit pollinia removal and deposition, and we calculated pollinator effectiveness and importance. Visitation rates varied significantly between the 2 yr of the study. Overall, Apis mellifera, Bombus sp., and Epargyreus clarus were the most important pollinators. However, Bombus sp. was the only visitor that was observed to both remove and insert pollinia for both parent species as well as hybrids. We conclude that Bombus may be a key agent of hybridization and introgression in these sympatric milkweed populations, and hybrids are neither preferred nor selected against by pollinators. Thus, we have identified a potential mechanism for how hybrids act as bridges to gene flow between A. exaltata and A. syriaca. These results provide insights into the breakdown of prezygotic isolating mechanisms.

  18. Population genomics of parallel hybrid zones in the mimetic butterflies, H. melpomene and H. erato

    Science.gov (United States)

    Ruiz, Mayté; Salazar, Patricio; Counterman, Brian; Medina, Jose Alejandro; Ortiz-Zuazaga, Humberto; Morrison, Anna; Papa, Riccardo

    2014-01-01

    Hybrid zones can be valuable tools for studying evolution and identifying genomic regions responsible for adaptive divergence and underlying phenotypic variation. Hybrid zones between subspecies of Heliconius butterflies can be very narrow and are maintained by strong selection acting on color pattern. The comimetic species, H. erato and H. melpomene, have parallel hybrid zones in which both species undergo a change from one color pattern form to another. We use restriction-associated DNA sequencing to obtain several thousand genome-wide sequence markers and use these to analyze patterns of population divergence across two pairs of parallel hybrid zones in Peru and Ecuador. We compare two approaches for analysis of this type of data—alignment to a reference genome and de novo assembly—and find that alignment gives the best results for species both closely (H. melpomene) and distantly (H. erato, ∼15% divergent) related to the reference sequence. Our results confirm that the color pattern controlling loci account for the majority of divergent regions across the genome, but we also detect other divergent regions apparently unlinked to color pattern differences. We also use association mapping to identify previously unmapped color pattern loci, in particular the Ro locus. Finally, we identify a new cryptic population of H. timareta in Ecuador, which occurs at relatively low altitude and is mimetic with H. melpomene malleti. PMID:24823669

  19. Can alternative mating tactics facilitate introgression across a hybrid zone by circumventing female choice?

    Science.gov (United States)

    Stewart, K A; Hudson, C M; Lougheed, S C

    2017-02-01

    Reproductive barriers and divergence in species' mate recognition systems underlie major models of speciation. However, hybridization between divergent species is common, and classic mechanisms to explain permeable reproductive barriers rarely consider how an individual may attain reproductive success. Alternative mating tactics (AMTs) exist in various forms across animal taxa. Such tactics may allow poorer quality individuals to gain mating opportunities and facilitate introgression either through asymmetrical positive selection or by circumventing female choice altogether in areas of secondary contact. One such tactic is satellite behaviour in frogs, where silent males perch near advertisers in an attempt to intercept females. To test whether such satellite male tactics are context-dependent and favoured by hybrids, we genotyped and quantified the morphology of 80 male spring peeper (Pseudacris crucifer) individuals involved in caller-satellite associations from a secondary contact zone between two intraspecific mitochondrial lineages. Irrespective of population, satellite behaviour was best predicted by size but not body condition. Within the contact zone, pure individuals showed a significantly greater probability of being active callers, whereas hybrids of one lineage were more likely to adopt the satellite tactic. We suggest that satellite behaviour in P. crucifer promotes introgression, breaks down reproductive isolating barriers and contributes to asymmetrical introgression in this secondary contact zone. AMTs may thus be an underexplored but important alternative to oft-discussed causes of genetic discordance found in hybrid zones.

  20. Multi-Zone hybrid model for failure detection of the stable ventilation systems

    DEFF Research Database (Denmark)

    Gholami, Mehdi; Schiøler, Henrik; Soltani, Mohsen;

    2010-01-01

    In this paper, a conceptual multi-zone model for climate control of a live stock building is elaborated. The main challenge of this research is to estimate the parameters of a nonlinear hybrid model. A recursive estimation algorithm, the Extended Kalman Filter (EKF) is implemented for estimation....

  1. Photoinduced Reductive Electron Transfer in LNA:DNA Hybrids

    DEFF Research Database (Denmark)

    Wenge, Ulrike; Wengel, Jesper; Wagenknecht, Hans-Achim

    2012-01-01

    Lock it, but not too much: LNA units (locked or bridging nucleic acids) in LNA:DNA hybrids lead to a negative effect on electron transfer (ET), but they also force the nucleic acid structure in the A-type double helix, which allows a better base stacking than the normal B-type and thus positively...... influences the ET. This result is significant for the design of nucleic acids of molecular electronics....

  2. The influence of distance between heat sources in hybrid welded plate on fusion zone geometry

    Directory of Open Access Journals (Sweden)

    W. Piekarska

    2011-04-01

    Full Text Available Results of numerical analysis into temperature field in hybrid laser-arc welding process with motion of liquid material taken intoaccount are presented in this study. On the basis of obtained results the influence of the distance between the arc foot point and the laserbeam focal point on the shape and size of fusion zone in hybrid butt welded plate. Temperature field was calculated on the basis ofsolution of transient heat transfer equation. The solution of Navier-Stokes equation allowed for simulation of fluid flow in the fusion zone.Fuzzy solidification front was assumed in calculations with linear approximation of solid fraction in solid-liquid region where liquidmaterial flow through porous medium is taken into consideration. Numerical solution algorithms were developed for three-dimensionalproblem. Established numerical model of hybrid welding process takes into account different electric arc and laser beam heat sourcespower distributions.

  3. Numerical modelling of liquid material flow in the fusion zone of hybrid welded joint

    Directory of Open Access Journals (Sweden)

    M. Kubiak

    2011-04-01

    Full Text Available This paper concerns modelling of liquid metal motion in the fusion zone of laser-arc hybrid butt-welded plate. Velocity field in the fusion zone and temperature field in welded plate were obtained on the basis of the solution of mass, momentum and energy conservationsequations. Differential equations were solved using Chorin’s projection method and finite volume method. Melting and solidificationprocesses were taken into account in calculations assuming fuzzy solidification front where fluid flow is treated as a flow through porous medium. Double-ellipsoidal heat source model was used to describe electric arc and laser beam heat sources. On the basis of developed solution algorithms simulation of hybrid welding process was performed and the influence of liquid metal motion in the fusion zone on the results of calculations was analyzed.

  4. Multi-locus estimates of population structure and migration in a fence lizard hybrid zone.

    Directory of Open Access Journals (Sweden)

    Adam D Leaché

    Full Text Available A hybrid zone between two species of lizards in the genus Sceloporus (S. cowlesi and S. tristichus on the Mogollon Rim in Arizona provides a unique opportunity to study the processes of lineage divergence and merging. This hybrid zone involves complex interactions between 2 morphologically and ecologically divergent subspecies, 3 chromosomal groups, and 4 mitochondrial DNA (mtDNA clades. The spatial patterns of divergence between morphology, chromosomes and mtDNA are discordant, and determining which of these character types (if any reflects the underlying population-level lineages that are of interest has remained impeded by character conflict. The focus of this study is to estimate the number of populations interacting in the hybrid zone using multi-locus nuclear data, and to then estimate the migration rates and divergence time between the inferred populations. Multi-locus estimates of population structure and gene flow were obtained from 12 anonymous nuclear loci sequenced for 93 specimens of Sceloporus. Population structure estimates support two populations, and this result is robust to changes to the prior probability distribution used in the Bayesian analysis and the use of spatially-explicit or non-spatial models. A coalescent analysis of population divergence suggests that gene flow is high between the two populations, and that the timing of divergence is restricted to the Pleistocene. The hybrid zone is more accurately described as involving two populations belonging to S. tristichus, and the presence of S. cowlesi mtDNA haplotypes in the hybrid zone is an anomaly resulting from mitochondrial introgression.

  5. Nanoleakage in Hybrid Layer and Acid-Base Resistant Zone at the Adhesive/Dentin Interface.

    Science.gov (United States)

    Nikaido, Toru; Nurrohman, Hamid; Takagaki, Tomohiro; Sadr, Alireza; Ichinose, Shizuko; Tagami, Junji

    2015-10-01

    The aim of interfacial nanoleakage evaluation is to gain a better understanding of degradation of the adhesive-dentin interface. The acid-base resistant zone (ABRZ) is recognized at the bonded interface under the hybrid layer (HL) in self-etch adhesive systems after an acid-base challenge. The purpose of this study was to evaluate nanoleakage in HL and ABRZ using three self-etch adhesives; Clearfil SE Bond (SEB), Clearfil SE One (SEO), and G-Bond Plus (GBP). One of the three adhesives was applied on the ground dentin surface and light cured. The specimens were longitudinally divided into two halves. One half remained as the control group. The others were immersed in ammoniacal silver nitrate solution, followed by photo developing solution under fluorescent light. Following this, the specimens were subjected to acid-base challenges with an artificial demineralization solution (pH4.5) and sodium hypochlorite, and prepared in accordance with common procedures for transmission electron microscopy (TEM) examination. The TEM images revealed silver depositions in HL and ABRZ due to nanoleakage in all the adhesives; however, the extent of nanoleakage was material dependent. Funnel-shaped erosion beneath the ABRZ was observed only in the all-in-one adhesive systems; SEO and GBP, but not in the two-step self-etch adhesive system; SEB.

  6. Electrostatic electron cyclotron instabilities near the upper hybrid layer due to electron ring distributions

    Science.gov (United States)

    Eliasson, B.; Speirs, D. C.; Daldorff, L. K. S.

    2016-09-01

    A theoretical study is presented of the electrostatic electron cyclotron instability involving Bernstein modes in a magnetized plasma. The presence of a tenuous thermal ring distribution in a Maxwellian plasma decreases the frequency of the upper hybrid branch of the electron Bernstein mode until it merges with the nearest lower branch with a resulting instability. The instability occurs when the upper hybrid frequency is somewhat above the third, fourth, and higher electron cyclotron harmonics, and gives rise to a narrow spectrum of waves around the electron cyclotron harmonic nearest to the upper hybrid frequency. For a tenuous cold ring distribution together with a Maxwellian distribution an instability can take place also near the second electron cyclotron harmonic. Noise-free Vlasov simulations are used to assess the theoretical linear growth-rates and frequency spectra, and to study the nonlinear evolution of the instability. The relevance of the results to laboratory and ionospheric heating experiments is discussed.

  7. Electronic properties of hybrid metal-discotic liquid crystal nanostructures

    Science.gov (United States)

    Kelsall, R. W.; Pecchia, A.; Bourlange, A.; Movaghar, B.; Evans, S. D.; Hickey, B. J.; Boden, N.

    2003-04-01

    A new class of hybrid organic/inorganic nanostructures, comprising self-organised discotic liquid crystal layers deposited on ultrathin metal films, has been investigated both experimentally and theoretically. Calculations show that the periodic self-organised molecular layer gives rise to a new, hybrid electronic bandstructure, resulting in modulation of the metal film conductivity. In situ conductivity measurements during deposition of such self-organised layers confirm that the metal film conductivity is altered. Theoretical modeling also shows that the AC conductivity should show structure related to the carrier trapping and one-dimensional transport features of the self-organised layer.

  8. Assortative mating and differential male mating success in an ash hybrid zone population

    Directory of Open Access Journals (Sweden)

    Frascaria-Lacoste Nathalie

    2006-11-01

    Full Text Available Abstract Background The structure and evolution of hybrid zones depend mainly on the relative importance of dispersal and local adaptation, and on the strength of assortative mating. Here, we study the influence of dispersal, temporal isolation, variability in phenotypic traits and parasite attacks on the male mating success of two parental species and hybrids by real-time pollen flow analysis. We focus on a hybrid zone population between the two closely related ash species Fraxinus excelsior L. (common ash and F. angustifolia Vahl (narrow-leaved ash, which is composed of individuals of the two species and several hybrid types. This population is structured by flowering time: the F. excelsior individuals flower later than the F. angustifolia individuals, and the hybrid types flower in-between. Hybrids are scattered throughout the population, suggesting favorable conditions for their local adaptation. We estimate jointly the best-fitting dispersal kernel, the differences in male fecundity due to variation in phenotypic traits and level of parasite attack, and the strength of assortative mating due to differences in flowering phenology. In addition, we assess the effect of accounting for genotyping error on these estimations. Results We detected a very high pollen immigration rate and a fat-tailed dispersal kernel, counter-balanced by slight phenological assortative mating and short-distance pollen dispersal. Early intermediate flowering hybrids, which had the highest male mating success, showed optimal sex allocation and increased selfing rates. We detected asymmetry of gene flow, with early flowering trees participating more as pollen donors than late flowering trees. Conclusion This study provides striking evidence that long-distance gene flow alone is not sufficient to counter-act the effects of assortative mating and selfing. Phenological assortative mating and short-distance dispersal can create temporal and spatial structuring that appears

  9. The role of climate in the dynamics of a hybrid zone in Appalachian salamanders

    Science.gov (United States)

    Walls, Susan

    2009-01-01

    I examined the potential influence of climate change on the dynamics of a previously studied hybrid zone between a pair of terrestrial salamanders at the Coweeta Hydrologic Laboratory, U.S. Forest Service, in the Nantahala Mountains of North Carolina, USA. A 16-year study led by Nelson G. Hairston, Sr. revealed that Plethodon teyahalee and Plethodon shermani hybridized at intermediate elevations, forming a cline between 'pure' parental P. teyahalee at lower elevations and 'pure' parental P. shermani at higher elevations. From 1974 to 1990 the proportion of salamanders at the higher elevation scored as 'pure' P. shermani declined significantly, indicating that the hybrid zone was spreading upward. To date there have been no rigorous tests of hypotheses for the movement of this hybrid zone. Using temperature and precipitation data from Coweeta, I re-analyzed Hairston's data to examine whether the observed elevational shift was correlated with variation in either air temperature or precipitation from the same time period. For temperature, my analysis tracked the results of the original study: the proportion of 'pure' P. shermani at the higher elevation declined significantly with increasing mean annual temperature, whereas the proportion of 'pure' P. teyahalee at lower elevations did not. There was no discernable relationship between proportions of 'pure' individuals of either species with variation in precipitation. From 1974 to 1990, low-elevation air temperatures at the Coweeta Laboratory ranged from annual means of 11.8 to 14.2 °C, compared with a 55-year average (1936-1990) of 12.6 °C. My re-analyses indicate that the upward spread of the hybrid zone is correlated with increasing air temperatures, but not precipitation, and provide an empirical test of a hypothesis for one factor that may have influenced this movement. My results aid in understanding the potential impact that climate change may have on the ecology and evolution of terrestrial salamanders in

  10. GA and PSO culled hybrid technique for economic dispatch problem with prohibited operating zones

    Institute of Scientific and Technical Information of China (English)

    SUDHAKARAN M.; AJAY-D-VIMALRAJ P.; PALANIVELU T.G.

    2007-01-01

    This paper presents an efficient and reliable genetic algorithm (GA) based particle swarm optimization (PSO) technique (hybrid GAPSO) for solving the economic dispatch (ED) problem in power systems. The non-linear characteristics of the generators, such as prohibited operating zones, ramp rate limits and non-smooth cost functions of the practical generator operation are considered. The proposed hybrid algorithm is demonstrated for three different systems and the performance is compared with the GA and PSO in terms of solution quality and computation efficiency. Comparison of results proved that the proposed algorithm can obtain higher quality solutions efficiently in ED problems. A comprehensive software package is developed using MATLAB.

  11. Zone Based Hybrid Feature Extraction Algorithm for Handwritten Numeral Recognition of South Indian Scripts

    Science.gov (United States)

    Rajashekararadhya, S. V.; Ranjan, P. Vanaja

    India is a multi-lingual multi script country, where eighteen official scripts are accepted and have over hundred regional languages. In this paper we propose a zone based hybrid feature extraction algorithm scheme towards the recognition of off-line handwritten numerals of south Indian scripts. The character centroid is computed and the image (character/numeral) is further divided in to n equal zones. Average distance and Average angle from the character centroid to the pixels present in the zone are computed (two features). Similarly zone centroid is computed (two features). This procedure is repeated sequentially for all the zones/grids/boxes present in the numeral image. There could be some zones that are empty, and then the value of that particular zone image value in the feature vector is zero. Finally 4*n such features are extracted. Nearest neighbor classifier is used for subsequent classification and recognition purpose. We obtained 97.55 %, 94 %, 92.5% and 95.2 % recognition rate for Kannada, Telugu, Tamil and Malayalam numerals respectively.

  12. Genetic structure, introgression, and a narrow hybrid zone between northern and California spotted owls (Strix occidentalis).

    Science.gov (United States)

    Barrowclough, G F; Groth, J G; Mertz, L A; Gutiérrez, R J

    2005-04-01

    The northern spotted owl (Strix occidentalis caurina) is a threatened subspecies and the California spotted owl (Strix occidentalis occidentalis) is a subspecies of special concern in the western United States. Concern for their continued viability has arisen because of habitat loss caused by timber harvesting. The taxonomic status of the northern subspecies has been the subject of continuing controversy. We investigated the phylogeographical and population genetic structure of northern and California spotted owls with special reference to their region of contact. Mitochondrial DNA (mtDNA) control region sequences confirmed the existence of two well-differentiated lineages connected by a narrow hybrid zone in a region of low population density in north central California. Maximum-likelihood estimates indicated bidirectional gene flow between the lineages but limited introgression outside the region of contact. The lengths of both the mtDNA hybrid zone and the reduced density patch were similar and slightly exceeded estimates of natal dispersal distances. This suggests that the two subspecies were in secondary contact in a hybrid zone trapped by a population density trough. Consequently, the zone of interaction is expected to be geographically stable. We discovered a third, rare clade of haplotypes, which we interpreted to be a result of incomplete lineage sorting; those haplotypes result in a paraphyletic northern spotted owl with respect to the California spotted owl. A congeneric species, the barred owl (Strix varia), occasionally hybridizes with spotted owls; our results indicated an upper bound for the frequency of barred owl mtDNA haplotypes in northern spotted owl populations of 3%.

  13. Demographic history of speciation in a Senecio altitudinal hybrid zone on Mt. Etna.

    Science.gov (United States)

    Filatov, Dmitry A; Osborne, Owen G; Papadopulos, Alexander S T

    2016-06-01

    Hybrid zones typically form as a result of species coming into secondary contact, but can also be established in situ as an ecotonal hybrid zone, a situation which has been reported far less frequently. An altitudinal hybrid zone on Mount Etna between two ragwort species (the low elevation Senecio chrysanthemifolius and high elevation S. aethnensis) could potentially represent either of these possibilities. However, a scenario of secondary contact vs. speciation with gene flow has not been explicitly tested. Here, we test these alternatives and demonstrate that the data do not support secondary contact. Furthermore, we report that the previous analyses of speciation history of these species were based on admixed populations, which has led to inflated estimates of ongoing, interspecific gene flow. Our new analyses, based on 'pure' S. aethnensis and S. chrysanthemifolius populations, reveal gene exchange of less than one effective migrant per generation, a level low enough to allow the species to accumulate neutral, genomewide differences. Overall, our results are consistent with a scenario of speciation with gene flow and a divergence time which coincides with the rise of Mt. Etna to altitudes above 2000 m (~150 KY). Further work to quantify the role of adaptation to contrasting environments of high and low altitudes will be needed to support the scenario of recent ecological speciation in this system.

  14. Bibliography of studies on hybrid zones of the common shrew chromosome races distributed in Russia

    Directory of Open Access Journals (Sweden)

    Rena Nadjafova

    2013-11-01

    Full Text Available The common shrew, Sorex araneus Linnaeus, 1758, has become a model species for cytogenetical and evolutionary studies after discovery of extraordinary Robertsonian polymorphism at the within-species level. Development of differential staining techniques (Q-, R-and G-banding made it possible to identify the chromosomal arms and their combination in racial karyotypes. Entering into contact with each other, the chromosomal races might form hybrid zones which represent a great interest for understanding of the process of speciation. Until recently all known hybrid zones of S. araneus were localized in Western Europe and only one was identified in Siberia (Russia between Novosibirsk and Tomsk races (Aniskin and Lukianova 1989, Searle and Wójcik 1998, Polyakov et al. 2011. However, rapidly growing number of reports on discovery of interracial hybrid zones of Sorex araneus in the European part of Russia and neighboring territories appeared lately. The aim of the present work is to compile the bibliography of all studies covering this topic regardless of the original language and the publishing source which hopefully could make research data more accessible to international scientists.It could also be a productive way to save current history of Sorex araneus researches in full context of the ISACC (International Sorex araneus Cytogenetics Committee heritage (Searle et al. 2007, Zima 2008.

  15. Strong natural selection on juveniles maintains a narrow adult hybrid zone in a broadcast spawner.

    Science.gov (United States)

    Prada, Carlos; Hellberg, Michael E

    2014-12-01

    Natural selection can maintain and help form species across different habitats, even when dispersal is high. Selection against inferior migrants (immigrant inviability) acts when locally adapted populations suffer high mortality on dispersal to unsuitable habitats. Habitat-specific populations undergoing divergent selection via immigrant inviability should thus show (1) a change in the ratio of adapted to nonadapted individuals among age/size classes and (2) a cline (defined by the environmental gradient) as selection counterbalances migration. Here we examine the frequencies of two depth-segregated lineages in juveniles and adults of a Caribbean octocoral, Eunicea flexuosa. Distributions of the two lineages in both shallow and deep environments were more distinct when inferred from adults than juveniles. Despite broad larval dispersal, we also found an extremely narrow hybrid zone (<100 m), with coincident clines for molecular and morphological characters of the host coral and its algal symbiont. Effective dispersal estimates derived from the hybrid zone are remarkably small (<20 m) for a broadcast spawner. The large selection coefficient against mismatched genotypes derived from cohort data is consistent with that from field transplant experiments. Narrow hybrid zones and limited effective dispersal may be a common outcome of long periods of postsettlement, prereproductive selection across steep ecological gradients. Strong diversifying selection provides a mechanism to explain the prevalence of depth-segregated sibling species in the sea.

  16. Relative contribution of dispersal and natural selection to the maintenance of a hybrid zone in Littorina.

    Science.gov (United States)

    Cruz, Raquel; Vilas, Carlos; Mosquera, Javier; García, Carlos

    2004-12-01

    Habitat preference behavior may play an important role in nonallopatric speciation. However, most examples of habitat preference contributing to differentiation within natural populations correspond to parasites or herbivores living in the discrete environments constituted by their animal or plant hosts. In the present study we investigated migration guided by habitat preference in the intertidal snail Littorina saxatilis in a hybrid zone associated with an ecotone across the shore, which is therefore a continuously varying environment. First, we found evidence for this behavior in one of the two locations studied. Second, we made reciprocal transplants to suppress the phenotypic gradient observed across the hybrid zone and measured the relative contributions of selection and migration to its regeneration. Selection played an important role at the two locations studied, but migration was only important at one, where it accounted for between a third and a half of the regenerated gradient. This overall minor effect of migration was relevant for theoretical models dealing with nonallopatric speciation, because it suggested that variation for habitat preference did not have an important role in the initiation of the differentiation process. The preference behavior observed in the hybrid zone would have evolved secondarily, as a consequence of habitat-dependent fitness differences between phenotypes.

  17. Large-scale multi-zone optimal power dispatch using hybrid hierarchical evolution technique

    Directory of Open Access Journals (Sweden)

    Manjaree Pandit

    2014-03-01

    Full Text Available A new hybrid technique based on hierarchical evolution is proposed for large, non-convex, multi-zone economic dispatch (MZED problems considering all practical constraints. Evolutionary/swarm intelligence-based optimisation techniques are reported to be effective only for small/medium-sized power systems. The proposed hybrid hierarchical evolution (HHE algorithm is specifically developed for solving large systems. The HHE integrates the exploration and exploitation capabilities of particle swarm optimisation and differential evolution in a novel manner such that the search efficiency is improved substantially. Most hybrid techniques export or exchange features or operations from one algorithm to the other, but in HHE their entire individual features are retained. The effectiveness of the proposed algorithm has been verified on six-test systems having different sizes and complexity levels. Non-convex MZED solution for such large and complex systems has not yet been reported.

  18. 75 FR 64248 - Approval for Manufacturing Authority Foreign-Trade Zone 196 ATC Logistics & Electronics (Cell...

    Science.gov (United States)

    2010-10-19

    ... & Electronics (Cell Phone Kitting) Fort Worth, TX Pursuant to its authority under the Foreign-Trade Zones Act of... following Order: Whereas, ATC Logistics & Electronics (ATCLE), an operator of Foreign-Trade Zone 196, has... procedures within FTZ 196 on behalf of ATC Logistics & Electronics, as described in the application...

  19. Electronic structure of hybrid interfaces for polymer-based electronics.

    Science.gov (United States)

    Fahlman, M; Crispin, A; Crispin, X; Henze, S K M; de Jong, M P; Osikowicz, W; Tengstedt, C; Salaneck, W R

    2007-05-08

    The fundamentals of the energy level alignment at anode and cathode electrodes in organic electronics are described. We focus on two different models that treat weakly interacting organic/metal (and organic/organic) interfaces: the induced density of interfacial states model and the so-called integer charge transfer model. The two models are compared and evaluated, mainly using photoelectron spectroscopy data of the energy level alignment of conjugated polymers and molecules at various organic/metal and organic/organic interfaces. We show that two different alignment regimes are generally observed: (i) vacuum level alignment, which corresponds to the lack of vacuum level offsets (Schottky-Mott limit) and hence the lack of charge transfer across the interface, and (ii) Fermi level pinning where the resulting work function of an organic/metal and organic/organic bilayer is independent of the substrate work function and an interface dipole is formed due to charge transfer across the interface. We argue that the experimental results are best described by the integer charge transfer model which predicts the vacuum level alignment when the substrate work function is above the positive charge transfer level and below the negative charge transfer level of the conjugated material. The model further predicts Fermi level pinning to the positive (negative) charge transfer level when the substrate work function is below (above) the positive (negative) charge transfer level. The nature of the integer charge transfer levels depend on the materials system: for conjugated large molecules and polymers, the integer charge transfer states are polarons or bipolarons; for small molecules' highest occupied and lowest unoccupied molecular orbitals and for crystalline systems, the relevant levels are the valence and conduction band edges. Finally, limits and further improvements to the integer charge transfer model are discussed as well as the impact on device design.

  20. Species distribution models contribute to determine the effect of climate and interspecific interactions in moving hybrid zones.

    Science.gov (United States)

    Engler, J O; Rödder, D; Elle, O; Hochkirch, A; Secondi, J

    2013-11-01

    Climate is a major factor delimiting species' distributions. However, biotic interactions may also be prominent in shaping geographical ranges, especially for parapatric species forming hybrid zones. Determining the relative effect of each factor and their interaction of the contact zone location has been difficult due to the lack of broad scale environmental data. Recent developments in species distribution modelling (SDM) now allow disentangling the relative contributions of climate and species' interactions in hybrid zones and their responses to future climate change. We investigated the moving hybrid zone between the breeding ranges of two parapatric passerines in Europe. We conducted SDMs representing the climatic conditions during the breeding season. Our results show a large mismatch between the realized and potential distributions of the two species, suggesting that interspecific interactions, not climate, account for the present location of the contact zone. The SDM scenarios show that the southerly distributed species, Hippolais polyglotta, might lose large parts of its southern distribution under climate change, but a similar gain of novel habitat along the hybrid zone seems unlikely, because interactions with the other species (H. icterina) constrain its range expansion. Thus, whenever biotic interactions limit range expansion, species may become 'trapped' if range loss due to climate change is faster than the movement of the contact zone. An increasing number of moving hybrid zones are being reported, but the proximate causes of movement often remain unclear. In a global context of climate change, we call for more interest in their interactions with climate change.

  1. Predicting Freeway Work Zone Delays and Costs with a Hybrid Machine-Learning Model

    Directory of Open Access Journals (Sweden)

    Bo Du

    2017-01-01

    Full Text Available A hybrid machine-learning model, integrating an artificial neural network (ANN and a support vector machine (SVM model, is developed to predict spatiotemporal delays, subject to road geometry, number of lane closures, and work zone duration in different periods of a day and in the days of a week. The model is very user friendly, allowing the least inputs from the users. With that the delays caused by a work zone on any location of a New Jersey freeway can be predicted. To this end, tremendous amounts of data from different sources were collected to establish the relationship between the model inputs and outputs. A comparative analysis was conducted, and results indicate that the proposed model outperforms others in terms of the least root mean square error (RMSE. The proposed hybrid model can be used to calculate contractor penalty in terms of cost overruns as well as incentive reward schedule in case of early work competition. Additionally, it can assist work zone planners in determining the best start and end times of a work zone for developing and evaluating traffic mitigation and management plans.

  2. Ecological and morphological studies in the hybrid zone between Pinus sibirica and Pinus pumila

    Directory of Open Access Journals (Sweden)

    S.N. Goroshkevich

    2013-12-01

    Full Text Available In the Baikal Region, there is no phenological isolation between Siberian stone pine (P. sibirica Du Tour and Siberian dwarf stone pine (P. pumila (Pall. Regel since the timing of their 'flowering' coincides. Morphologically intermediate individuals, supposedly natural hybrids,occur not very often. In the west half of Stanovoye upland area four regions were investigated: Barguzinskiy, Baikalskiy, Verchneangarskiy and the Severo-Myiskiy mountain ridges. Interspecific natural hybridization was found to take place in several overlapping regions of the species' ranges; however there are some differences in frequency of natural hybrid occurrence between regions as well as within each region. Great numbers of natural hybrids are found only in a specific habitat which occurs rarely and occupies a relatively small area. At the north-east coast of Lake Baikal the lakeside zone is occupied by Siberian stone pine forests with moderate participation of Siberian dwarf stone pine in the undergrowth. The natural hybrid are widespread everywhere. The ratio of fructiferous Siberian stone pine, Siberian dwarf stone pine and natural hybrid was found to be approximately 300:10:1. About 90% of the examined natural hybrids took an intermediate position between the two parental species by most features (structure of needles, shoots, and crown, i.e. representing putatively the first generation hybrids. Therefore, in contrast to the parental species they are subjected to the destructive effect of snowbreak (broken off or dislocated from part of the root system. Like the Siberian dwarf stone pine the natural hybrid has specific root sources forming from latent buds. Therefore, the hybrids are not subjected to ageing, as well as have no internal limitation of age and size. Siberian dwarf stone pine, Siberian stone pine and their natural hybrid grow together in the Upper Angara delta in the bog regions. In the most productive sites the ratio of fructiferous Siberian dwarf

  3. Ecological and morphological studies in the hybrid zone between Pinus sibirica and Pinus pumila

    Directory of Open Access Journals (Sweden)

    S.N. Goroshkevich

    2013-12-01

    Full Text Available In the Baikal Region, there is no phenological isolation between Siberian stone pine (P. sibirica Du Tour and Siberian dwarf stone pine (P. pumila (Pall. Regel since the timing of their 'flowering' coincides. Morphologically intermediate individuals, supposedly natural hybrids,occur not very often. In the west half of Stanovoye upland area four regions were investigated: Barguzinskiy, Baikalskiy, Verchneangarskiy and the Severo-Myiskiy mountain ridges. Interspecific natural hybridization was found to take place in several overlapping regions of the species' ranges; however there are some differences in frequency of natural hybrid occurrence between regions as well as within each region. Great numbers of natural hybrids are found only in a specific habitat which occurs rarely and occupies a relatively small area. At the north-east coast of Lake Baikal the lakeside zone is occupied by Siberian stone pine forests with moderate participation of Siberian dwarf stone pine in the undergrowth. The natural hybrid are widespread everywhere. The ratio of fructiferous Siberian stone pine, Siberian dwarf stone pine and natural hybrid was found to be approximately 300:10:1. About 90% of the examined natural hybrids took an intermediate position between the two parental species by most features (structure of needles, shoots, and crown, i.e. representing putatively the first generation hybrids. Therefore, in contrast to the parental species they are subjected to the destructive effect of snowbreak (broken off or dislocated from part of the root system. Like the Siberian dwarf stone pine the natural hybrid has specific root sources forming from latent buds. Therefore, the hybrids are not subjected to ageing, as well as have no internal limitation of age and size. Siberian dwarf stone pine, Siberian stone pine and their natural hybrid grow together in the Upper Angara delta in the bog regions. In the most productive sites the ratio of fructiferous Siberian dwarf

  4. Is Hybridization a Source of Adaptive Venom Variation in Rattlesnakes? A Test, Using a Crotalus scutulatus × viridis Hybrid Zone in Southwestern New Mexico.

    Science.gov (United States)

    Zancolli, Giulia; Baker, Timothy G; Barlow, Axel; Bradley, Rebecca K; Calvete, Juan J; Carter, Kimberley C; de Jager, Kaylah; Owens, John Benjamin; Price, Jenny Forrester; Sanz, Libia; Scholes-Higham, Amy; Shier, Liam; Wood, Liam; Wüster, Catharine E; Wüster, Wolfgang

    2016-06-16

    Venomous snakes often display extensive variation in venom composition both between and within species. However, the mechanisms underlying the distribution of different toxins and venom types among populations and taxa remain insufficiently known. Rattlesnakes (Crotalus, Sistrurus) display extreme inter- and intraspecific variation in venom composition, centered particularly on the presence or absence of presynaptically neurotoxic phospholipases A₂ such as Mojave toxin (MTX). Interspecific hybridization has been invoked as a mechanism to explain the distribution of these toxins across rattlesnakes, with the implicit assumption that they are adaptively advantageous. Here, we test the potential of adaptive hybridization as a mechanism for venom evolution by assessing the distribution of genes encoding the acidic and basic subunits of Mojave toxin across a hybrid zone between MTX-positive Crotalus scutulatus and MTX-negative C. viridis in southwestern New Mexico, USA. Analyses of morphology, mitochondrial and single copy-nuclear genes document extensive admixture within a narrow hybrid zone. The genes encoding the two MTX subunits are strictly linked, and found in most hybrids and backcrossed individuals, but not in C. viridis away from the hybrid zone. Presence of the genes is invariably associated with presence of the corresponding toxin in the venom. We conclude that introgression of highly lethal neurotoxins through hybridization is not necessarily favored by natural selection in rattlesnakes, and that even extensive hybridization may not lead to introgression of these genes into another species.

  5. Is Hybridization a Source of Adaptive Venom Variation in Rattlesnakes? A Test, Using a Crotalus scutulatus × viridis Hybrid Zone in Southwestern New Mexico

    Directory of Open Access Journals (Sweden)

    Giulia Zancolli

    2016-06-01

    Full Text Available Venomous snakes often display extensive variation in venom composition both between and within species. However, the mechanisms underlying the distribution of different toxins and venom types among populations and taxa remain insufficiently known. Rattlesnakes (Crotalus, Sistrurus display extreme inter- and intraspecific variation in venom composition, centered particularly on the presence or absence of presynaptically neurotoxic phospholipases A2 such as Mojave toxin (MTX. Interspecific hybridization has been invoked as a mechanism to explain the distribution of these toxins across rattlesnakes, with the implicit assumption that they are adaptively advantageous. Here, we test the potential of adaptive hybridization as a mechanism for venom evolution by assessing the distribution of genes encoding the acidic and basic subunits of Mojave toxin across a hybrid zone between MTX-positive Crotalus scutulatus and MTX-negative C. viridis in southwestern New Mexico, USA. Analyses of morphology, mitochondrial and single copy-nuclear genes document extensive admixture within a narrow hybrid zone. The genes encoding the two MTX subunits are strictly linked, and found in most hybrids and backcrossed individuals, but not in C. viridis away from the hybrid zone. Presence of the genes is invariably associated with presence of the corresponding toxin in the venom. We conclude that introgression of highly lethal neurotoxins through hybridization is not necessarily favored by natural selection in rattlesnakes, and that even extensive hybridization may not lead to introgression of these genes into another species.

  6. A protected area influences genotype-specific survival and the structure of a Canis hybrid zone.

    Science.gov (United States)

    Benson, John F; Patterson, Brent R; Mahoney, Peter J

    2014-02-01

    It is widely recognized that protected areas can strongly influence ecological systems and that hybridization is an important conservation issue. However, previous studies have not explicitly considered the influence of protected areas on hybridization dynamics. Eastern wolves are a species of special concern and their distribution is largely restricted to a protected population in Algonquin Provincial Park (APP), Ontario, Canada, where they are the numerically dominant canid. We studied intrinsic and extrinsic factors influencing survival and cause-specific mortality of hybrid and parental canids in the three-species hybrid zone between eastern wolves, eastern coyotes, and gray wolves in and adjacent to APP. Mortality risk for eastern wolves in areas adjacent to APP was significantly higher than for other sympatric Canis types outside of APP, and for eastern wolves and other canids within APP. Outside of APP, the annual mortality rate of all canids by harvest (24%) was higher than for other causes of death (4-7%). Furthermore, eastern wolves (hazard ratio = 3.5) and nonresidents (transients and dispersing animals, hazard ratio = 2.7) were more likely to die from harvest relative to other Canis types and residents, respectively. Thus, eastern wolves dispersing from APP were especially vulnerable to harvest mortality. For residents, eastern wolf survival was more negatively influenced by increased road density than for other Canis types, further highlighting the sensitivity of eastern wolves to human disturbance. A cycle of dispersal from APP followed by high rates of mortality and hybridization appears to maintain eastern wolves at low density adjacent to APP, limiting the potential for expansion beyond the protected area. However, high survival and numerical dominance of eastern wolves within APP suggest that protected areas can allow rare hybridizing species to persist even if their demographic performance is compromised and barriers to hybridization are largely

  7. Impacts of climate warming on hybrid zone movement: Geographically diffuse and biologically porous "species borders"

    Institute of Scientific and Technical Information of China (English)

    J. Mark Scriber

    2011-01-01

    The ecology and evolutionary biology of insect-plant associations has realized extensive attention, especially during the past 60 years. The classifications (categorical designations) of continuous variation in biodiversity, ranging from global patterns (e.g., latitudinal gradients in species richness/diversity and degree of herbivore feeding specialization) to localized insect-plant associations that span the biospectrum from polyphenisms,polymorphisms, biotypes, demes, host races, to cryptic species, remain academically contentious. Semantic and biosystematic (taxonomical) disagreements sometimes detract from more important ecological and evolutionary processes that drive diversification, the dynarnics of gene flow and local extinctions. This review addresses several aspects of insect specialization, host-associated divergence and ecological (including "hybrid") speciation,with special reference to the climate warming impacts on species borders of hybridizing swallowtail butterflies (Papilionidae). Interspecific hybrid introgression may result in collapse of multi-species communities or increase species numbers via homoploid hybrid speeiation. We may see diverging, merging, or emerging genotypes across hybrid zones,all part of the ongoing processes of evolution. Molecular analyses of genetic mosaics and genomic dynamics with "divergence hitchhiking", combined with ecological, ethological and physiological studies of "species porosity", have already begun to unveil some answers for some important ecological/evolutionary questions. (i) How rapidly can host-associated divergence lead to new species (and why doesn't it always do so, e.g., resulting in "incomplete" speciation)? (ii) How might "speeiation genes" function, and how/where would we find them? (iii) Can oscillations from specialists to generalists and back to specialists help explain global diversity in herbivorous insects? (iv) How could recombinant interspecific hybridization lead to divergence and

  8. Contact and hybrid zone hotspots and evolution of birds in the Middle East

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Middle East is an important contact zone for a considerable number of bird taxa from the western and eastern Palearctic and from the great Saharo-Sindian jesert belt. Using WORLDMAP software, we analyzed the geographical distribution of secondary contact zones for parapatric species pairs of birds in the Middle East. We identified 56 species (29 species pairs) that make contact in the Middle East. The species pairs belong to three orders, i.e. Falconiformes, Piciformes, and Passeriformes. Almost half (46%) of these species pairs hybridize in their contact zones. Although contact zones occur over a large part of northern Middle East, spatially they were not evenly distributed. Contact zone richness was highest in the mountain ranges south of the Caspian Sea and the Caucasus. The hottest hotspots, where up to nine bird species pairs occur sympatrically, are situated in north-eastern Iran and Azerbaijan. We discuss the relevance of these hotspots for improving our understanding of the biogeography and evolution of the avifauna in the Middle East.

  9. 75 FR 15413 - Approval for Processing Authority, Foreign-Trade Zone 196, ATC Logistics & Electronics (Personal...

    Science.gov (United States)

    2010-03-29

    ... & Electronics (Personal Navigation Devices), Fort Worth, Texas Pursuant to its authority under the Foreign-Trade...) adopts the following Order: Whereas, ATC Logistics & Electronics, an operator of Foreign-Trade Zone...

  10. Hybrid [5]Radialenes with Bispyrroloheteroles: New Electron-Donating Units.

    Science.gov (United States)

    Higashino, Tomohiro; Imahori, Hiroshi

    2015-09-14

    Bispyrroloheteroles have been synthesized to address their intrinsic structural, optical, and electrochemical properties. The X-ray crystal structures and calculated natural bond orbital (NBO) bond orders unambiguously demonstrated the existence of a two pyrrole-fused five-membered ring with short exocyclic C-C double bonds and long endocyclic C-C single bonds, supporting that the bispyrroloheteroles are rare examples of structurally characterized hybrid [5]radialenes. The bispyrroloheteroles were found to act as an electron-donating unit, which would be fascinating for the rational design of new charge-transporting and donor-acceptor photovoltaic materials as well as versatile charge-transfer complexes.

  11. Transmission electron microscopy of unstained hybrid Au nanoparticles capped with PPAA (plasma-poly-allylamine)

    DEFF Research Database (Denmark)

    Gontard, Lionel C.; Fernández, Asunción; Dunin-Borkowski, Rafal E.;

    2014-01-01

    Hybrid (organic shell-inorganic core) nanoparticles have important applications in nanomedicine. Although the inorganic components of hybrid nanoparticles can be characterized readily using conventional transmission electron microscopy (TEM) techniques, the structural and chemical arrangement of ...

  12. Structural and electronic properties of hybrid silicon-germanium nanosheets

    Directory of Open Access Journals (Sweden)

    F. L. Pérez Sánchez

    2014-12-01

    Full Text Available Using first principles molecular calculations, based on the Density Functional Theory (DFT, structural and electronic properties of hybrid graphene—like silicon—germanium circular nanosheets of hexagonal symmetry are investigated. The exchange—correlation functional of Perdew—Wang (PW in the local spin density approximation (LSDA based on the pseudopotentials of Dolg—Bergnre is applied. The finite extension nanosheets are represented by the CnHm—like cluster model with mono—hydrogenated armchair edges. Changes of the physicochemical properties were analyzed to learn on the chemical composition. We have obtained that the corrugation of the hybrid nanosheets is maintained (with respect to the pristine nanosheets of Ge and Si and is more pronounced when there is a high percentage of germanium. Moreover, hybrid nanosheets have ionic bonds (polarity in the interval from 0.18 to 0.77 D and exhibit a semimetal behavior. Three types of chemical compositions are considered: 1 the one—one relationship, 2 formation of Ge dimers and 3 formation of Ge hexagons. In each case it is observed an increase in the chemical reactivity. Finally, analyzing the work function we conclude that in cases 1 and 2 the chemical compositions improve the efficiency of the field emission and thereby they could expand the scope of nanotechnology applications.

  13. Electron imaging with Medipix2 hybrid pixel detector

    CERN Document Server

    McMullan, G; Chen, S; Henderson, R; Llopart, X; Summerfield, C; Tlustos, L; Faruqi, A R

    2007-01-01

    The electron imaging performance of Medipix2 is described. Medipix2 is a hybrid pixel detector composed of two layers. It has a sensor layer and a layer of readout electronics, in which each 55 μm×55 μm pixel has upper and lower energy discrimination and MHz rate counting. The sensor layer consists of a 300 μm slab of pixellated monolithic silicon and this is bonded to the readout chip. Experimental measurement of the detective quantum efficiency, DQE(0) at 120 keV shows that it can reach 85% independent of electron exposure, since the detector has zero noise, and the DQE(Nyquist) can reach 35% of that expected for a perfect detector (4/π2). Experimental measurement of the modulation transfer function (MTF) at Nyquist resolution for 120 keV electrons using a 60 keV lower energy threshold, yields a value that is 50% of that expected for a perfect detector (2/π). Finally, Monte Carlo simulations of electron tracks and energy deposited in adjacent pixels have been performed and used to calculate expected v...

  14. A LINEAR HYBRID MODEL OF MSE AND BEM FOR FLOATING STRUCTURES IN COASTAL ZONES

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun; MIAO Guo-ping

    2006-01-01

    A linear hybrid model of Mild Slope Equation (MSE) and Boundary Element Method (BEM) is developed to study the wave propagation around floating structures in coastal zones. Both the wave refraction under the influence of topography and the wave diffraction by floating structures are considered. Hence, the model provides wave properties around the coastal floating structures of arbitrary shape but also the wave forces on and the hydrodynamic characteristics of the structures. Different approaches are compared to demonstrate the validity of the present hybrid model. Several numerical tests are carried out for the cases of pontoons under different circumstances. The results show that the influence of topography on the hydrodynamic characteristics of floating structures in coastal regions is important and must not be ignored in the most wave period range with practical interests.

  15. Electronic heat current rectification in hybrid superconducting devices

    Energy Technology Data Exchange (ETDEWEB)

    Fornieri, Antonio, E-mail: antonio.fornieri@sns.it; Giazotto, Francesco, E-mail: francesco.giazotto@sns.it [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa (Italy); Martínez-Pérez, María José [Physikalisches Institut - Experimentalphysik II Universität Tübingen, D-72076 Tübingen (Germany)

    2015-05-15

    In this work, we review and expand recent theoretical proposals for the realization of electronic thermal diodes based on tunnel-junctions of normal metal and superconducting thin films. Starting from the basic rectifying properties of a single hybrid tunnel junction, we will show how the rectification efficiency can be largely increased by combining multiple junctions in an asymmetric chain of tunnel-coupled islands. We propose three different designs, analyzing their performance and their potential advantages. Besides being relevant from a fundamental physics point of view, this kind of devices might find important technological application as fundamental building blocks in solid-state thermal nanocircuits and in general-purpose cryogenic electronic applications requiring energy management.

  16. Electron-phonon coupling in hybrid lead halide perovskites

    Science.gov (United States)

    Wright, Adam D.; Verdi, Carla; Milot, Rebecca L.; Eperon, Giles E.; Pérez-Osorio, Miguel A.; Snaith, Henry J.; Giustino, Feliciano; Johnston, Michael B.; Herz, Laura M.

    2016-05-01

    Phonon scattering limits charge-carrier mobilities and governs emission line broadening in hybrid metal halide perovskites. Establishing how charge carriers interact with phonons in these materials is therefore essential for the development of high-efficiency perovskite photovoltaics and low-cost lasers. Here we investigate the temperature dependence of emission line broadening in the four commonly studied formamidinium and methylammonium perovskites, HC(NH2)2PbI3, HC(NH2)2PbBr3, CH3NH3PbI3 and CH3NH3PbBr3, and discover that scattering from longitudinal optical phonons via the Fröhlich interaction is the dominant source of electron-phonon coupling near room temperature, with scattering off acoustic phonons negligible. We determine energies for the interacting longitudinal optical phonon modes to be 11.5 and 15.3 meV, and Fröhlich coupling constants of ~40 and 60 meV for the lead iodide and bromide perovskites, respectively. Our findings correlate well with first-principles calculations based on many-body perturbation theory, which underlines the suitability of an electronic band-structure picture for describing charge carriers in hybrid perovskites.

  17. Electron-phonon coupling in hybrid lead halide perovskites.

    Science.gov (United States)

    Wright, Adam D; Verdi, Carla; Milot, Rebecca L; Eperon, Giles E; Pérez-Osorio, Miguel A; Snaith, Henry J; Giustino, Feliciano; Johnston, Michael B; Herz, Laura M

    2016-05-26

    Phonon scattering limits charge-carrier mobilities and governs emission line broadening in hybrid metal halide perovskites. Establishing how charge carriers interact with phonons in these materials is therefore essential for the development of high-efficiency perovskite photovoltaics and low-cost lasers. Here we investigate the temperature dependence of emission line broadening in the four commonly studied formamidinium and methylammonium perovskites, HC(NH2)2PbI3, HC(NH2)2PbBr3, CH3NH3PbI3 and CH3NH3PbBr3, and discover that scattering from longitudinal optical phonons via the Fröhlich interaction is the dominant source of electron-phonon coupling near room temperature, with scattering off acoustic phonons negligible. We determine energies for the interacting longitudinal optical phonon modes to be 11.5 and 15.3 meV, and Fröhlich coupling constants of ∼40 and 60 meV for the lead iodide and bromide perovskites, respectively. Our findings correlate well with first-principles calculations based on many-body perturbation theory, which underlines the suitability of an electronic band-structure picture for describing charge carriers in hybrid perovskites.

  18. FOXP1 status in splenic marginal zone lymphoma: a fluorescence in situ hybridization and immunohistochemistry approach.

    Science.gov (United States)

    Baró, Cristina; Espinet, Blanca; Salido, Marta; Colomo, Lluís; Luño, Elisa; Florensa, Lourdes; Ferrer, Ana; Salar, Antonio; Campo, Elias; Serrano, Sergi; Solé, Francesc

    2009-11-01

    Splenic marginal zone lymphoma (SMZL) is a well-recognized entity in which chromosomal aberrations seem to be potential markers in diagnosis, prognosis and disease monitoring. FOXP1 is a transcriptional regulator of B lymphopoiesis that is deregulated in some types of NHL. Translocation t(3;14)(p14;q32) has been described in marginal zone lymphomas but few series have studied FOXP1 involvement in SMZL. We performed cytogenetic, fluorescence in situ hybridization (FISH) and immunohistochemical (IHC) studies in a series of 36 patients in order to study the status of FOXP1 in this entity. According to our results, FOXP1 is not rearranged in SMZL, although we were able to demonstrate gains of FOXP1 gene due to trisomy 3/3p by FISH. FOXP1 protein expression seemed to be not related to any aberration and IHC studies are not conclusive.

  19. Stable Heliconius butterfly hybrid zones are correlated with a local rainfall peak at the edge of the Amazon basin.

    Science.gov (United States)

    Rosser, Neil; Dasmahapatra, Kanchon K; Mallet, James

    2014-12-01

    Multilocus clines between Müllerian mimetic races of Heliconius butterflies provide a classic example of the maintenance of hybrid zones and their importance in speciation. Concordant hybrid zones in the mimics Heliconius erato and H. melpomene in northern Peru were carefully documented in the 1980s, and this prior work now permits a historical analysis of the movement or stasis of the zones. Previous work predicted that these zones might be moving toward the Andes due to selective asymmetry. Extensive deforestation and climate change might also be expected to affect the positions and widths of the hybrid zones. We show that the positions and shapes of these hybrid zones have instead remained remarkably stable between 1985 and 2012. The stability of this interaction strongly implicates continued selection, rather than neutral mixing following secondary contact. The stability of cline widths and strong linkage disequilibria (gametic correlation coefficients Rmax = 0.35-0.56 among unlinked loci) over 25 years suggest that mimetic selection pressures on each color pattern locus have remained approximately constant (s ≈ 0.13-0.40 per locus in both species). Exceptionally high levels of precipitation at the edge of the easternmost Andes may act as a population density trough for butterflies, trapping the hybrid zones at the foot of the mountains, and preventing movement. As such, our results falsify one prediction of the Pleistocene Refugium theory: That the ranges of divergent species or subspecies should be centered on regions characterized by maxima of rainfall, with hybrid zones falling in more arid regions between them.

  20. Influences of Root Zone Restriction and Nitrogen Nutrition on Hybrid Wheat Growth

    Institute of Scientific and Technical Information of China (English)

    ZHANGRONGIAN; SHENZHENGUO; 等

    1997-01-01

    To study the physiological effects of small root zone,plants of a hybrid wheat variety(Triticum aestivum L.cv.Meiyou 4) were grown in small pots(1 litre)or large pots(8 litre) with low nitrogen(50 mg kg-1 soil) and high nitrogen(200 mg kg-1 soil).Restricting root zone decreased dry weight of plants at the stages of stem elongation and flowering ,compared to those of control plants grown in the large pots(P<0.01).Spraying of 6-benzylaminopurine(50 μmol L01) increased dry weight of plants and chlorophyll concentration in leaves. restriction of root zone decreased the concentrations of total nitrogen,chlorophyll and soluble protein in the flag leaf and accelerated senescence of the leaves,Supply of high nitrogen delayed senescence of the flag leaf.The results suggested that the shortage of nutrients ,especially nitrogen deficiency,was the primary reason for the decreased growth of plant in the treatment of root zone restriction.

  1. Hybrid gate dielectric materials for unconventional electronic circuitry.

    Science.gov (United States)

    Ha, Young-Geun; Everaerts, Ken; Hersam, Mark C; Marks, Tobin J

    2014-04-15

    Recent advances in semiconductor performance made possible by organic π-electron molecules, carbon-based nanomaterials, and metal oxides have been a central scientific and technological research focus over the past decade in the quest for flexible and transparent electronic products. However, advances in semiconductor materials require corresponding advances in compatible gate dielectric materials, which must exhibit excellent electrical properties such as large capacitance, high breakdown strength, low leakage current density, and mechanical flexibility on arbitrary substrates. Historically, conventional silicon dioxide (SiO2) has dominated electronics as the preferred gate dielectric material in complementary metal oxide semiconductor (CMOS) integrated transistor circuitry. However, it does not satisfy many of the performance requirements for the aforementioned semiconductors due to its relatively low dielectric constant and intransigent processability. High-k inorganics such as hafnium dioxide (HfO2) or zirconium dioxide (ZrO2) offer some increases in performance, but scientists have great difficulty depositing these materials as smooth films at temperatures compatible with flexible plastic substrates. While various organic polymers are accessible via chemical synthesis and readily form films from solution, they typically exhibit low capacitances, and the corresponding transistors operate at unacceptably high voltages. More recently, researchers have combined the favorable properties of high-k metal oxides and π-electron organics to form processable, structurally well-defined, and robust self-assembled multilayer nanodielectrics, which enable high-performance transistors with a wide variety of unconventional semiconductors. In this Account, we review recent advances in organic-inorganic hybrid gate dielectrics, fabricated by multilayer self-assembly, and their remarkable synergy with unconventional semiconductors. We first discuss the principals and functional

  2. Trade-off between morphological convergence and opportunistic diet behavior in fish hybrid zone

    Directory of Open Access Journals (Sweden)

    Grey Jonathan

    2009-10-01

    Full Text Available Abstract Background The invasive Chondrostoma nasus nasus has colonized part of the distribution area of the protected endemic species Chondrostoma toxostoma toxostoma. This hybrid zone is a complex system where multiple effects such as inter-species competition, bi-directional introgression, strong environmental pressure and so on are combined. Why do sympatric Chondrostoma fish present a unidirectional change in body shape? Is this the result of inter-species interactions and/or a response to environmental effects or the result of trade-offs? Studies focusing on the understanding of a trade-off between multiple parameters are still rare. Although this has previously been done for Cichlid species flock and for Darwin finches, where mouth or beak morphology were coupled to diet and genetic identification, no similar studies have been done for a fish hybrid zone in a river. We tested the correlation between morphology (body and mouth morphology, diet (stable carbon and nitrogen isotopes and genomic combinations in different allopatric and sympatric populations for a global data set of 1330 specimens. To separate the species interaction effect from the environmental effect in sympatry, we distinguished two data sets: the first one was obtained from a highly regulated part of the river and the second was obtained from specimens coming from the less regulated part. Results The distribution of the hybrid combinations was different in the two part of the sympatric zone, whereas all the specimens presented similar overall changes in body shape and in mouth morphology. Sympatric specimens were also characterized by a larger diet behavior variance than reference populations, characteristic of an opportunistic diet. No correlation was established between the body shape (or mouth deformation and the stable isotope signature. Conclusion The Durance River is an untamed Mediterranean river despite the presence of numerous dams that split the river from

  3. Trade-off between morphological convergence and opportunistic diet behavior in fish hybrid zone.

    Science.gov (United States)

    Corse, Emmanuel; Costedoat, Caroline; Pech, Nicolas; Chappaz, Rémi; Grey, Jonathan; Gilles, André

    2009-10-27

    The invasive Chondrostoma nasus nasus has colonized part of the distribution area of the protected endemic species Chondrostoma toxostoma toxostoma. This hybrid zone is a complex system where multiple effects such as inter-species competition, bi-directional introgression, strong environmental pressure and so on are combined. Why do sympatric Chondrostoma fish present a unidirectional change in body shape? Is this the result of inter-species interactions and/or a response to environmental effects or the result of trade-offs? Studies focusing on the understanding of a trade-off between multiple parameters are still rare. Although this has previously been done for Cichlid species flock and for Darwin finches, where mouth or beak morphology were coupled to diet and genetic identification, no similar studies have been done for a fish hybrid zone in a river. We tested the correlation between morphology (body and mouth morphology), diet (stable carbon and nitrogen isotopes) and genomic combinations in different allopatric and sympatric populations for a global data set of 1330 specimens. To separate the species interaction effect from the environmental effect in sympatry, we distinguished two data sets: the first one was obtained from a highly regulated part of the river and the second was obtained from specimens coming from the less regulated part. The distribution of the hybrid combinations was different in the two part of the sympatric zone, whereas all the specimens presented similar overall changes in body shape and in mouth morphology. Sympatric specimens were also characterized by a larger diet behavior variance than reference populations, characteristic of an opportunistic diet. No correlation was established between the body shape (or mouth deformation) and the stable isotope signature. The Durance River is an untamed Mediterranean river despite the presence of numerous dams that split the river from upstream to downstream. The sympatric effect on morphology and

  4. HOST SPECIFICITY AND THE GENETIC STRUCTURE OF TWO YUCCA MOTH SPECIES IN A YUCCA HYBRID ZONE.

    Science.gov (United States)

    Leebens-Mack, Jim; Pellmyr, Olle; Brock, Marcus

    1998-10-01

    Host specialization is an important mechanism of diversification among phytophagous insects, especially when they are tightly associated with their hosts. The well-known obligate pollination mutualism between yucca moths and yuccas represent such an association, but the degree of host specificity and modes of specialization in moth evolution is unclear. Here we use molecular tools to test the morphology-based hypothesis that the moths pollinating two yuccas, Yucca baccata and Y. schidigera, are distinct species. Host specificity was assessed in a zone of sympatry where the hosts are known to hybridize. Because the moths are the only pollinators, the plant hybrids are evidence that the moths occasionally perform heterospecific pollination. Nucleotide variation was assessed in a portion of the mitochondrial gene COI, and in an intron within a nuclear lysozyme gene. Moths pollinating Y. baccata and Y. schidigera were inferred to be genetically isolated because there was no overlap in alleles at either locus, and all but one of the moths was found on their native host in the hybrid zone. Moreover, genetic structure was very weak across the range of each moth species: estimates of FST for the lysozyme intron were 0.043 (SE = ± 0.004) and 0.021 (SE = ± 0.006) for the baccata and schidigera pollinators, respectively; estimated FST for COI in the baccata moths was 0.228 (± 0.012), whereas schidigera pollinators were fixed for a single allele. These results reveal a high level of migration among widely separated moth populations. We predict that pollen-mediated gene flow among conspecific yuccas is considerable and hypothesize that geographic separation is a limited barrier both for yuccas and for yucca moths. © 1998 The Society for the Study of Evolution.

  5. Universal logic gates via liquid-electronic hybrid divider

    KAUST Repository

    Zhou, Bingpu

    2012-01-01

    We demonstrated two-input microdroplet-based universal logic gates using a liquid-electronic hybrid divider. All 16 Boolean logic functions have been realized by manipulating the applied voltages. The novel platform consists of a microfluidic chip with integrated microdroplet detectors and external electronic components. The microdroplet detectors act as the communication media for fluidic and electronic information exchange. The presence or absence of microdroplets at the detector translates into the binary signal 1 or 0. The embedded micro-mechanical pneumatically actuated valve (PAV), fabricated using the well-developed multilayer soft lithography technique, offers biocompatibility, flexibility and accuracy for the on-chip realization of different logic functions. The microfluidic chip can be scaled up to construct large-scale microfluidic logic computation. On the other hand, the microfluidic chip with a specific logic function can be applied to droplet-based chemical reactions for on-demand bio or chemical analysis. Our experimental results have presented an autonomously driven, precision-controlled microfluidic chip for chemical reactions based on the IF logic function. © 2012 The Royal Society of Chemistry.

  6. Variation in phenotype, parasite load and male competitive ability across a cryptic hybrid zone.

    Directory of Open Access Journals (Sweden)

    Devi Stuart-Fox

    Full Text Available BACKGROUND: Molecular genetic studies are revealing an increasing number of cryptic lineages or species, which are highly genetically divergent but apparently cannot be distinguished morphologically. This observation gives rise to three important questions: 1 have these cryptic lineages diverged in phenotypic traits that may not be obvious to humans; 2 when cryptic lineages come into secondary contact, what are the evolutionary consequences: stable co-existence, replacement, admixture or differentiation and 3 what processes influence the evolutionary dynamics of these secondary contact zones? METHODOLOGY/PRINCIPAL FINDINGS: To address these questions, we first tested whether males of the Iberian lizard Lacerta schreiberi from two highly genetically divergent, yet morphologically cryptic lineages on either side of an east-west secondary contact could be differentiated based on detailed analysis of morphology, coloration and parasite load. Next, we tested whether these differences could be driven by pre-copulatory intra-sexual selection (male-male competition. Compared to eastern males, western males had fewer parasites, were in better body condition and were more intensely coloured. Although subtle environmental variation across the hybrid zone could explain the differences in parasite load and body condition, these were uncorrelated with colour expression, suggesting that the differences in coloration reflect heritable divergence. The lineages did not differ in their aggressive behaviour or competitive ability. However, body size, which predicted male aggressiveness, was positively correlated with the colour traits that differed between genetic backgrounds. CONCLUSIONS/SIGNIFICANCE: Our study confirms that these cryptic lineages differ in several aspects that are likely to influence fitness. Although there were no clear differences in male competitive ability, our results suggest a potential indirect role for intra-sexual selection. Specifically

  7. Electron transport in a mesoscopic superconducting ferromagnetic hybrid conductor

    Energy Technology Data Exchange (ETDEWEB)

    Giroud, M.; Hasselbach, K.; Courtois, H.; Pannetier, B. [Centre de Recherche sur les Tres Basses Temperatures, CNRS, 38 - Grenoble (France); Mailly, D. [Laboratoire de Photonique et de Nanostructures, 91 - Marcoussis (France)

    2003-01-01

    We present electrical transport experiments performed on submicron hybrid devices made of a ferromagnetic conductor (Co) and a superconducting (Al) electrode. The sample was patterned in order to separate the contributions of the Co conductor and of the Co-Al interface. We observed a strong influence of the Al electrode superconductivity on the resistance of the Co conductor. This effect is large only when the interface is highly transparent. We characterized the dependence of the observed resistance decrease on temperature, bias current and magnetic field. As the differential resistance of the ferromagnet exhibits a non-trivial asymmetry, we claim that the magnetic domain structure plays an important role in the electron transport properties of superconducting / ferromagnetic conductors. (authors)

  8. Mapping Seasonal Evapotranspiration and Root Zone Soil Moisture using a Hybrid Modeling Approach over Vineyards

    Science.gov (United States)

    Geli, H. M. E.

    2015-12-01

    Estimates of actual crop evapotranspiration (ETa) at field scale over the growing season are required for improving agricultural water management, particularly in water limited and drought prone regions. Remote sensing data from multiple platforms such as airborne and Landsat-based sensors can be used to provide these estimates. Combining these data with surface energy balance models can provide ETa estimates at sub- field scale as well as information on vegetation stress and soil moisture conditions. However, the temporal resolution of airborne and Landsat data does not allow for a continuous ETa monitoring over the course of the growing season. This study presents the application of a hybrid ETa modeling approach developed for monitoring daily ETa and root zone available water at high spatial resolutions. The hybrid ETa modeling approach couples a thermal-based energy balance model with a water balance-based scheme using data assimilation. The two source energy balance (TSEB) model is used to estimate instantaneous ETa which can be extrapolated to daily ETa using a water balance model modified to use the reflectance-based basal crop coefficient for interpolating ETa in between airborne and/or Landsat overpass dates. Moreover, since it is a water balance model, the soil moisture profile is also estimated. The hybrid ETa approach is applied over vineyard fields in central California. High resolution airborne and Landsat imagery were used to drive the hybrid model. These images were collected during periods that represented different vine phonological stages in 2013 growing season. Estimates of daily ETa and surface energy balance fluxes will be compared with ground-based eddy covariance tower measurements. Estimates of soil moisture at multiple depths will be compared with measurements.

  9. Hybrid LC filter for power electronic drives. Theory and implementation

    Energy Technology Data Exchange (ETDEWEB)

    Dzhankhotov, V.

    2009-07-01

    Power electronic converter drives use, for the sake of high efficiency, pulse-width modulation that results in sequences of high-voltage high-frequency steep-edged pulses. Such a signal contains a set of high harmonics not required for control purposes. Harmonics cause reflections in the cable between the motor and the inverter leading to faster winding insulation ageing. Bearing failures and problems with electromagnetic compatibility may also result. Electrical du/dt filters provide an effective solution to problems caused by pulse-width modulation, thereby increasing the performance and service life of the electrical machines. It is shown that RLC filters effectively decrease the reflection phenomena in the cable. Improved (simple, but effective) solutions are found for both differential- and common-mode signals; these solutions use a galvanic connection between the RLC filter star point and the converter DC link. Foil chokes and film capacitors are among the most widely used components in high-power applications. In actual applications they can be placed in different parts of the cabinet. This fact complicates the arrangement of the cabinet and decreases the reliability of the system. In addition, the inductances of connection wires may prevent filtration at high frequencies. This thesis introduces a new hybrid LC filter that uses a natural capacitance between the turns of the foil choke based on integration of an auxiliary layer into it. The main idea of the hybrid LC filter results from the fact that both the foil choke and the film capacitors have the same roll structure. Moreover, the capacitance between the turns ('intra capacitance') of the foil inductors is the reason for the deterioration of their properties at high frequencies. It is shown that the proposed filter has a natural cancellation of the intra capacitance. A hybrid LC filter may contain two or more foil layers isolated from each other and coiled on a core. The core material can be

  10. Hybridization in the Ensatina Ring Species, Strong selection against hybrids at a hybrid zone in the ensatina ring species complex and its evolutionary implications

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrino, Joao; Baird, Stuart J.E.; Lawson, Lucinda; Macey, J. Robert; Moritz, Craig; Wake, David B.

    2005-04-22

    The analysis of interactions between lineages at varying levels of genetic divergence can provide insights into the process of speciation through the accumulation of incompatible mutations. Ring species, and especially the Ensatina eschscholtzii system exemplify this approach. The plethodontid salamanders Ensatina eschscholtzii xanthoptica and Ensatina eschscholtzii platensis hybridize in the Central Sierran foothills of California. We compared the genetic structure across two transects (southern and northern Calaveras Co.), one of which was re-sampled over 20 years, and examined diagnostic molecular markers (eight allozyme loci and mitochondrial DNA) and a diagnostic quantitative trait (color pattern). Key results across all studies were: (i) cline centers for all markers were coincident and the zones were narrow, with width estimates of 730m to 2000m; (ii) cline centers at the northern Calaveras transect were coincident between 1981 and 2001, demonstrating repeatability over 5 generations; (iii) there are very few if any putative F1's, but a relatively high number of backcrossed individuals (57-86 percent) in the central portion of transects; (iv) we found substantial linkage disequilibrium in all three studies and strong heterozygote deficit both in northern Calaveras, in 2001, and southern Calaveras. Both linkage disequilibrium and heterozygote deficit show maximum values near the center of the zones (R and Fis, approx. equal to 0.5). Using estimates of cline width and dispersal, we infer strong selection against hybrids (s* approx. equal to 46-75 percent). This is sufficient to promote accumulation of differences at loci that are neutral or under divergent selection, but would still allow for introgression of adaptive alleles. The evidence for strong, but incomplete isolation across this centrally located contact is consistent with theory suggesting a gradual increase in postzygotic incompatibility between allopatric populations subject to divergent

  11. Reduced density matrix hybrid approach: application to electronic energy transfer.

    Science.gov (United States)

    Berkelbach, Timothy C; Markland, Thomas E; Reichman, David R

    2012-02-28

    Electronic energy transfer in the condensed phase, such as that occurring in photosynthetic complexes, frequently occurs in regimes where the energy scales of the system and environment are similar. This situation provides a challenge to theoretical investigation since most approaches are accurate only when a certain energetic parameter is small compared to others in the problem. Here we show that in these difficult regimes, the Ehrenfest approach provides a good starting point for a dynamical description of the energy transfer process due to its ability to accurately treat coupling to slow environmental modes. To further improve on the accuracy of the Ehrenfest approach, we use our reduced density matrix hybrid framework to treat the faster environmental modes quantum mechanically, at the level of a perturbative master equation. This combined approach is shown to provide an efficient and quantitative description of electronic energy transfer in a model dimer and the Fenna-Matthews-Olson complex and is used to investigate the effect of environmental preparation on the resulting dynamics.

  12. Spatial genetic and morphologic structure of wolves and coyotes in relation to environmental heterogeneity in a Canis hybrid zone.

    Science.gov (United States)

    Benson, John F; Patterson, Brent R; Wheeldon, Tyler J

    2012-12-01

    Eastern wolves have hybridized extensively with coyotes and gray wolves and are listed as a 'species of special concern' in Canada. However, a distinct population of eastern wolves has been identified in Algonquin Provincial Park (APP) in Ontario. Previous studies of the diverse Canis hybrid zone adjacent to APP have not linked genetic analysis with field data to investigate genotype-specific morphology or determine how resident animals of different ancestry are distributed across the landscape in relation to heterogeneous environmental conditions. Accordingly, we studied resident wolves and coyotes in and adjacent to APP to identify distinct Canis types, clarify the extent of the APP eastern wolf population beyond the park boundaries and investigate fine-scale spatial genetic structure and landscape-genotype associations in the hybrid zone. We documented three genetically distinct Canis types within the APP region that also differed morphologically, corresponding to putative gray wolves, eastern wolves and coyotes. We also documented a substantial number of hybrid individuals (36%) that were admixed between 2 or 3 of the Canis types. Breeding eastern wolves were less common outside of APP, but occurred in some unprotected areas where they were sympatric with a diverse combination of coyotes, gray wolves and hybrids. We found significant spatial genetic structure and identified a steep cline extending west from APP where the dominant genotype shifted abruptly from eastern wolves to coyotes and hybrids. The genotypic pattern to the south and northwest was a more complex mosaic of alternating genotypes. We modelled genetic ancestry in response to prey availability and human disturbance and found that individuals with greater wolf ancestry occupied areas of higher moose density and fewer roads. Our results clarify the structure of the Canis hybrid zone adjacent to APP and provide unique insight into environmental conditions influencing hybridization dynamics between

  13. Lower hybrid current drive favoured by electron cyclotron radiofrequency heating

    Energy Technology Data Exchange (ETDEWEB)

    Cesario, R.; Cardinali, A.; Castaldo, C.; Marinucci, M.; Tuccillo, A. A. [Associazione EURATOM/ENEA sulla Fusione, Centro Ricerche Frascati, 00044, Frascati (Italy); Amicucci, L.; Galli, A. [Università di Roma Sapienza, Dipartimento Ingegneria Elettronica, Rome (Italy); Giruzzi, G. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Napoli, F.; Schettini, G. [Università di Roma Tre, Dipartimento Ingegneria Elettronica, Rome (Italy)

    2014-02-12

    The important goal of adding to the bootstrap a fraction of non-inductive plasma current, which would be controlled for obtaining and optimizing steady-state profiles, can be reached by using the Current Drive produced by Lower Hybrid waves (LHCD). FTU (Frascati Tokamak Upgrade) experiments demonstrated, indeed, that LHCD is effective at reactor-graded high plasma density, and the LH spectral broadening is reduced, operating with higher electron temperature in the outer region of plasma column (T{sub e-periphery}). This method was obtained following the guidelines of theoretical predictions indicating that the broadening of launched spectrum produced by parametric instability (PI) should be reduced, and the LHCD effect at high density consequently enabled, under higher (T{sub e-periphery}). In FTU, the temperature increase in the outer plasma region was obtained by operating with reduced particle recycling, lithized walls and deep gas fuelling by means of fast pellet. Heating plasma periphery with electron cyclotron resonant waves (ECRH) will provide a further tool for achieving steady-state operations. New FTU experimental results are presented here, demonstrating that temperature effect at the plasma periphery, affecting LH penetration, occurs in a range of plasma parameters broader than in previous work. New information is also shown on the modelling assessing frequencies and growth rates of the PI coupled modes responsible of spectral broadening. Finally, we present the design of an experiment scheduled on FTU next campaign, where ECRH power is used to slightly increase the electron temperature in the outer plasma region of a high-density discharge aiming at restoring LHCD. Consequent to model results, by operating with a toroidal magnetic field of 6.3 T, useful for locating the electron cyclotron resonant layer at the periphery of the plasma column (r/a∼0.8, f{sub 0}=144 GHz), an increase of T{sub e} in the outer plasma (from 40 eV to 80 eV at r/a∼0.8) is

  14. The electronics hybrid of the ATLAS-SCT endcap detector modules

    CERN Document Server

    Ketterer, C

    2004-01-01

    An electronics hybrid has been developed for the ATLAS silicon microstrip tracker endcaps. The high-density interconnect board carries 12 readout ASICs, as well as ASICs for the optical data transmission. Special requirements are that this hybrid has to be double sided, radiation hard, and low mass. A six-layer flexible circuit in copper-polyimide technology has been chosen for this purpose. It is folded around a highly heat conducting carbon-carbon composite substrate to form the rigid double-sided hybrid. Adequate thermal, mechanical, and electrical performance of the hybrid has been demonstrated. The production of the hybrids started in May 2003. (12 refs).

  15. Hybrid additive manufacturing of 3D electronic systems

    Science.gov (United States)

    Li, J.; Wasley, T.; Nguyen, T. T.; Ta, V. D.; Shephard, J. D.; Stringer, J.; Smith, P.; Esenturk, E.; Connaughton, C.; Kay, R.

    2016-10-01

    A novel hybrid additive manufacturing (AM) technology combining digital light projection (DLP) stereolithography (SL) with 3D micro-dispensing alongside conventional surface mount packaging is presented in this work. This technology overcomes the inherent limitations of individual AM processes and integrates seamlessly with conventional packaging processes to enable the deposition of multiple materials. This facilitates the creation of bespoke end-use products with complex 3D geometry and multi-layer embedded electronic systems. Through a combination of four-point probe measurement and non-contact focus variation microscopy, it was identified that there was no obvious adverse effect of DLP SL embedding process on the electrical conductivity of printed conductors. The resistivity maintained to be less than 4  ×  10-4 Ω · cm before and after DLP SL embedding when cured at 100 °C for 1 h. The mechanical strength of SL specimens with thick polymerized layers was also identified through tensile testing. It was found that the polymerization thickness should be minimised (less than 2 mm) to maximise the bonding strength. As a demonstrator a polymer pyramid with embedded triple-layer 555 LED blinking circuitry was successfully fabricated to prove the technical viability.

  16. One- and many-electron self-interaction error in local and global hybrid functionals

    Science.gov (United States)

    Schmidt, Tobias; Kümmel, Stephan

    2016-04-01

    Electronic self-interaction poses a fundamental challenge in density-functional theory. It greatly limits, e.g., the physical interpretation of eigenvalues as electron removal energies. We here investigate whether local hybrid functionals that are designed to be free from one-electron self-interaction lead to occupied Kohn-Sham eigenvalues and orbitals that approximate photoemission observables well. We compare the local hybrid results to the ones from global hybrid functionals that only partially counteract the self-interaction, and to the results that are obtained with a Perdew-Zunger-type self-interaction correction. Furthermore, we check whether being nominally free from one-electron self-interaction translates into a reduced many-electron self-interaction error. Our findings show that this is not the case for the local hybrid functionals that we studied: In practice they are similar to global hybrids in many respects, despite being formally superior. This finding indicates that there is a conceptual difference between the Perdew-Zunger way and the local hybrid way of translating the one-electron condition to a many-electron system. We also point out and solve some difficulties that occur when using local hybrid functionals in combination with pseudopotentials.

  17. Genotype, soil type, and locale effects on reciprocal transplant vigor, endophyte growth, and microbial functional diversity of a narrow sagebrush hybrid zone in Salt Creek Canyon, Utah

    Science.gov (United States)

    Miglia, K.J.; McArthur, E.D.; Redman, R.S.; Rodriguez, R.J.; Zak, J.C.; Freeman, D.C.

    2007-01-01

    When addressing the nature of ecological adaptation and environmental factors limiting population ranges and contributing to speciation, it is important to consider not only the plant's genotype and its response to the environment, but also any close interactions that it has with other organisms, specifically, symbiotic microorganisms. To investigate this, soils and seedlings were reciprocally transplanted into common gardens of the big sagebrush hybrid zone in Salt Creek Canyon, Utah, to determine location and edaphic effects on the fitness of parental and hybrid plants. Endophytic symbionts and functional microbial diversity of indigenous and transplanted soils and sagebrush plants were also examined. Strong selection occurred against the parental genotypes in the middle hybrid zone garden in middle hybrid zone soil; F1 hybrids had the highest fitness under these conditions. Neither of the parental genotypes had superior fitness in their indigenous soils and habitats; rather F1 hybrids with the nonindigenous maternal parent were superiorly fit. Significant garden-by-soil type interactions indicate adaptation of both plant and soil microorganisms to their indigenous soils and habitats, most notably in the middle hybrid zone garden in middle hybrid zone soil. Contrasting performances of F1 hybrids suggest asymmetrical gene flow with mountain, rather than basin, big sagebrush acting as the maternal parent. We showed that the microbial community impacted the performance of parental and hybrid plants in different soils, likely limiting the ranges of the different genotypes.

  18. Hybrid fluorescence and electron cryo-microscopy for simultaneous electron and photon imaging.

    Science.gov (United States)

    Iijima, Hirofumi; Fukuda, Yoshiyuki; Arai, Yoshihiro; Terakawa, Susumu; Yamamoto, Naoki; Nagayama, Kuniaki

    2014-01-01

    Integration of fluorescence light and transmission electron microscopy into the same device would represent an important advance in correlative microscopy, which traditionally involves two separate microscopes for imaging. To achieve such integration, the primary technical challenge that must be solved regards how to arrange two objective lenses used for light and electron microscopy in such a manner that they can properly focus on a single specimen. To address this issue, both lateral displacement of the specimen between two lenses and specimen rotation have been proposed. Such movement of the specimen allows sequential collection of two kinds of microscopic images of a single target, but prevents simultaneous imaging. This shortcoming has been made up by using a simple optical device, a reflection mirror. Here, we present an approach toward the versatile integration of fluorescence and electron microscopy for simultaneous imaging. The potential of simultaneous hybrid microscopy was demonstrated by fluorescence and electron sequential imaging of a fluorescent protein expressed in cells and cathodoluminescence imaging of fluorescent beads. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Electron dispersion events in the morningside auroral zone and their relationship with VLF emissions

    Science.gov (United States)

    Hardy, David A.; Burke, William J.; Villalon, Elena

    1990-05-01

    This paper reports on observations of electron precipitation bursts observed in the morningside auroral zone with the J sensor, an electron detector aboard the Hilat satellite. The characteristics of these precipitation events are documented, and a theoretical explanation that could account for the observed properties is presented. According to this model, the dispersion events result from impulsive interactions of the electrons with intense asymmetric packets of VLF waves via the nonlinear ponderomotive force.

  20. AN APPLICATION OF HYBRID CLUSTERING AND NEURAL BASED PREDICTION MODELLING FOR DELINEATION OF MANAGEMENT ZONES

    Directory of Open Access Journals (Sweden)

    Babankumar S. Bansod

    2011-02-01

    Full Text Available Starting from descriptive data on crop yield and various other properties, the aim of this study is to reveal the trends on soil behaviour, such as crop yield. This study has been carried out by developing web application that uses a well known technique- Cluster Analysis. The cluster analysis revealed linkages between soil classes for the same field as well as between different fields, which can be partly assigned to crops rotation and determination of variable soil input rates. A hybrid clustering algorithm has been developed taking into account the traits of two clustering technologies: i Hierarchical clustering, ii K-means clustering. This hybrid clustering algorithm is applied to sensor- gathered data about soil and analysed, resulting in the formation of well delineatedmanagement zones based on various properties of soil, such as, ECa , crop yield, etc. One of the purposes of the study was to identify the main factors affecting the crop yield and the results obtained were validated with existing techniques. To accomplish this purpose, geo-referenced soil information has been examined. Also, based on this data, statistical method has been used to classify and characterize the soil behaviour. This is done using a prediction model, developed to predict the unknown behaviour of clusters based on the known behaviour of other clusters. In predictive modeling, data has been collected for the relevant predictors, a statistical model has been formulated, predictions were made and the model can be validated (or revised as additional data becomes available. The model used in the web application has been formed taking into account neural network based minimum hamming distance criterion.

  1. Genetic structure of Populus hybrid zone along the Irtysh River provides insight into plastid-nuclear incompatibility.

    Science.gov (United States)

    Zeng, Yan-Fei; Zhang, Jian-Guo; Duan, Ai-Guo; Abuduhamiti, Bawerjan

    2016-06-16

    In plants, the maintenance of species integrity despite hybridization has often been explained by the co-adaption of nuclear gene complexes. However, the interaction between plastid and nuclear sub-genomes has been underestimated. Here, we analyzed the genetic structure of a Populus alba and P. tremula hybrid zone along the Irtysh River system in the Altai region, northwest China, using both nuclear microsatellites and plastid DNA sequences. We found high interspecific differentiation, although the hybrid P. × canescens was prevalent. Bayesian inference classified most hybrids into F1, followed by a few back-crosses to P. alba, and fewer F2 hybrids and back-crosses to P. tremula, indicating a few introgressions but preference toward P. alba. When plastid haplotypes in parental species were distinct, P. × canescens carried the haplotypes of both parents, but showed significant linkage between intraspecific haplotype and nuclear genotypes at several microsatellite loci. Selection, rather than migration and assortative mating, might have contributed to such plastid-nuclear disequilibria. By removing later-generated hybrids carrying interspecific combinations of haplotype and nuclear genotypes, plastid-nuclear incompatibility has greatly limited the gene exchange between P. alba and P. tremula via backcrossing with hybrids, demonstrating a significant association between plastid haplotype and the proportion of nuclear admixture.

  2. Fast electron dynamics in lower hybrid current drive experiment on HT-7 tokamak

    Institute of Scientific and Technical Information of China (English)

    Shi Yue-Jiang; Kuang Gang-Li; Li Jian-Gang; HT-7 Team; Wan Bao-Nian; Chen Zhong-Yong; Hu Li-Qun; Lin Shi-Yao; Ruan Huai-Lin; Qian Jin-Ping; Zhen Xiang-Jun; Ding Bo-Jiang

    2005-01-01

    The dynamic behaviour of fast electron in lower hybrid current drive (LHCD) experiments is a crucial issue in the sense of enhancing plasma performance. A new hard x-ray diagnostic system on HT-7 allows the investigation of the lower hybrid wave dynamics. The behaviour of fast electron is studied in several kinds of LHCD experiments, including long pulse discharges, high performance discharges and counter-LHCD experiments.

  3. New hybrid genetic particle swarm optimization algorithm to design multi-zone binary filter.

    Science.gov (United States)

    Lin, Jie; Zhao, Hongyang; Ma, Yuan; Tan, Jiubin; Jin, Peng

    2016-05-16

    The binary phase filters have been used to achieve an optical needle with small lateral size. Designing a binary phase filter is still a scientific challenge in such fields. In this paper, a hybrid genetic particle swarm optimization (HGPSO) algorithm is proposed to design the binary phase filter. The HGPSO algorithm includes self-adaptive parameters, recombination and mutation operations that originated from the genetic algorithm. Based on the benchmark test, the HGPSO algorithm has achieved global optimization and fast convergence. In an easy-to-perform optimizing procedure, the iteration number of HGPSO is decreased to about a quarter of the original particle swarm optimization process. A multi-zone binary phase filter is designed by using the HGPSO. The long depth of focus and high resolution are achieved simultaneously, where the depth of focus and focal spot transverse size are 6.05λ and 0.41λ, respectively. Therefore, the proposed HGPSO can be applied to the optimization of filter with multiple parameters.

  4. Genetic analysis of an ephemeral intraspecific hybrid zone in the hypervariable tree, Metrosideros polymorpha, on Hawai'i Island.

    Science.gov (United States)

    Stacy, E A; Johansen, J B; Sakishima, T; Price, D K

    2016-09-01

    Intraspecific hybrid zones involving long-lived woody species are rare and can provide insights into the genetic basis of early-diverging traits in speciation. Within the landscape-dominant Hawaiian tree, Metrosideros polymorpha, are morphologically distinct successional varieties, incana and glaberrima, that dominate new and old lava flows, respectively, below 1200 me on volcanically active Hawai'i Island, with var. glaberrima also extending to higher elevations and bogs. Here, we use morphological measurements on 86 adult trees to document the presence of an incana-glaberrima hybrid zone on the 1855 Mauna Loa lava flow on east Hawai'i Island and parent-offspring analysis of 1311 greenhouse seedlings from 71 crosses involving 72 adults to estimate heritabilities and genetic correlations among vegetative traits. Both the variation in adult leaf pubescence at the site and the consistency between adult and offspring phenotypes suggest the presence of two hybrid classes, F1s and var. incana backcrosses, as would be expected on a relatively young lava flow. Nine nuclear microsatellite loci failed to distinguish parental and hybrid genotypes. All four leaf traits examined showed an additive genetic basis with moderate to strong heritabilities, and genetic correlations were stronger for the more range-restricted var. incana. The differences between varieties in trait values, heritabilities and genetic correlations, coupled with high genetic variation within but low genetic variation between varieties, are consistent with a multi-million-year history of alternating periods of disruptive selection in contrasting environments and admixture in ephemeral hybrid zones. Finally, the contrasting genetic architectures suggest different evolutionary trajectories of leaf traits in these forms.

  5. Comments on the energy selective precipitation of inner zone electrons by Imhof et al

    Science.gov (United States)

    Vampola, A. L.; Kuck, G. A.

    1981-12-01

    This note addresses the interpretation of data from the 1971-89A satellite as published by Imhof et al, in 'The Energy Selective Precipitation of Inner Zone Electrons' in the Journal of Geophysical Research. It discusses the limitations of the data set and demonstrates that the data set is in agreement with the thesis that a source of electron precipitation is colocated with the Soviet VLF transmitter UMS.

  6. Simulating Strongly Correlated Electron Systems with Hybrid Monte Carlo

    Institute of Scientific and Technical Information of China (English)

    LIU Chuan

    2000-01-01

    Using the path integral representation, the Hubbard and the periodic Anderson model on D-dimensional cubic lattice are transformed into field theories of fermions in D + 1 dimensions. These theories at half-filling possess a positive definite real symmetry fermion matrix and can be simulated using the hybrid Monte Carlo method.

  7. Genetic differentiation and inferred dynamics of a hybrid zone between Northern Spotted Owls (Strix occidentalis caurina) and California Spotted Owls (S. o. occidentalis) in northern California

    Science.gov (United States)

    Miller, Mark P.; Mullins, Tom; Forsman, Eric D.; Haig, Susan M.

    2017-01-01

    Genetic differentiation among Spotted Owl (Strix occidentalis) subspecies has been established in prior studies. These investigations also provided evidence for introgression and hybridization among taxa but were limited by a lack of samples from geographic regions where subspecies came into close contact. We analyzed new sets of samples from Northern Spotted Owls (NSO: S. o. caurina) and California Spotted Owls (CSO: S. o. occidentalis) in northern California using mitochondrial DNA sequences (mtDNA) and 10 nuclear microsatellite loci to obtain a clearer depiction of genetic differentiation and hybridization in the region. Our analyses revealed that a NSO population close to the northern edge of the CSO range in northern California (the NSO Contact Zone population) is highly differentiated relative to other NSO populations throughout the remainder of their range. Phylogenetic analyses identified a unique lineage of mtDNA in the NSO Contact Zone, and Bayesian clustering analyses of the microsatellite data identified the Contact Zone as a third distinct population that is differentiated from CSO and NSO found in the remainder of the subspecies' range. Hybridization between NSO and CSO was readily detected in the NSO Contact Zone, with over 50% of individuals showing evidence of hybrid ancestry. Hybridization was also identified among 14% of CSO samples, which were dispersed across the subspecies' range in the Sierra Nevada Mountains. The asymmetry of hybridization suggested that the hybrid zone may be dynamic and moving. Although evidence of hybridization existed, we identified no F1 generation hybrid individuals. We instead found evidence for F2 or backcrossed individuals among our samples. The absence of F1 hybrids may indicate that (1) our 10 microsatellites were unable to distinguish hybrid types, (2) primary interactions between subspecies are occurring elsewhere on the landscape, or (3) dispersal between the subspecies' ranges is reduced relative to

  8. Slow electron energy balance for hybrid models of direct-current glow discharges

    Science.gov (United States)

    Eliseev, S. I.; Bogdanov, E. A.; Kudryavtsev, A. A.

    2017-09-01

    In this paper, we present the formulation of slow electron energy balance for hybrid models of direct current (DC) glow discharge. Electrons originating from non-local ionization (secondary) contribute significantly to the energy balance of slow electrons. An approach towards calculating effective energy brought by a secondary electron to the group of slow electrons by means of Coulomb collisions is suggested. The value of effective energy shows a considerable dependence on external parameters of a discharge, such as gas pressure, type, and geometric parameters. The slow electron energy balance was implemented into a simple hybrid model that uses analytical formulation for the description of non-local ionization by fast electrons. Simulations of short (without positive column) DC glow discharge in argon are carried out for a range of gas pressures. Comparison with experimental data showed generally good agreement in terms of current-voltage characteristics, electron density, and electron temperature. Simulations also capture the trend of increasing electron density with decreasing pressure observed in the experiment. Analysis shows that for considered conditions, the product of maximum electron density ne and electron temperature Te in negative glow is independent of gas pressure and depends on the gas type, cathode material, and discharge current. Decreasing gas pressure reduces the heating rate of slow electrons during Coulomb collisions with secondary electrons, which leads to lower values of Te and, in turn, higher maximum ne.

  9. 75 FR 13484 - Foreign-Trade Zone 22; Temporary/Interim Manufacturing Authority; LG Electronics Mobilecomm USA...

    Science.gov (United States)

    2010-03-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE Foreign-Trade Zones Board Foreign-Trade Zone 22; Temporary/Interim Manufacturing Authority; LG Electronics... Electronics Mobilecomm USA, Inc. (LGEMU), to process cell phone kits under FTZ procedures within FTZ...

  10. Tunable hybridization of electronic states of graphene and a metal surface

    OpenAIRE

    Gruneis, Alexander; Vyalikh, Denis

    2008-01-01

    We present an approach to monitor and control the strength of the hybridization between electronic states of graphene and metal surfaces. Inspecting the distribution of the $\\pi$ band in a high-quality graphene layer synthesized on Ni(111) by angle-resolved photoemission, we observe a new "kink" feature which indicates a strong hybridization between $\\pi$ and \\textit{d} states of graphene and nickel, respectively. Upon deposition and gradual intercalation of potassium atoms into the graphene/...

  11. Polymer-metal hybrid transparent electrodes for flexible electronics

    National Research Council Canada - National Science Library

    Kang, Hongkyu; Jung, Suhyun; Jeong, Soyeong; Kim, Geunjin; Lee, Kwanghee

    2015-01-01

    Despite nearly two decades of research, the absence of ideal flexible and transparent electrodes has been the largest obstacle in realizing flexible and printable electronics for future technologies...

  12. Preparation and property of a novel soluble electron transport POSS-based hybrid material

    Institute of Scientific and Technical Information of China (English)

    Xin Wang; Juan Shen; Jin Cui Wu; Min Fang; Hong Yao Xu

    2008-01-01

    A novel POSS-based organic/inorganic hybrid covalently attached at molecular level, 2-(4-(allyloxy)phenyl)-5-(4-(octyloxy)phenyl)-1,3,4-oxadiazole-POSS (6) (abbreviated as oxadiazole-POSS) was synthesized by Pt (dcp) catalyst. The hybrid was soluble in common organic solvents such as CHCl3, toluene, C2H4Cl2, and THF. Its structures and properties were characterized and evaluated with FTIR, 1H NMR, 13C NMR, 29Si NMR, EA, TGA, DSC, GPC, and CV, respectively. The results show that the novel hybrid possesses high thermal stability and good electron injection ability.

  13. Interaction of runaway electrons with lower hybrid waves via anomalous Doppler broadening

    Science.gov (United States)

    Martín-Solís, J. R.; Sánchez, R.; Esposito, B.

    2002-05-01

    Due to the relativistic decrease of the electron cyclotron frequency, a cyclotron resonance may appear between runaway electrons and lower hybrid waves. A single particle description of the runaway dynamics [J. R. Martín-Solís et al., Phys. Plasmas 5, 2370 (1998)] is extended to analyze the effect of the interaction of runaway electrons with lower hybrid waves via anomalous Doppler broadening. The conditions under which the resonant interaction can play a role in limiting the runaway energy are established and it is shown that, under typical lower hybrid current drive operation parameters, an efficient wave-particle coupling may occur. Observations of a fast pitch angle scattering event during the current decay phase of Ohmic discharges in the Toroidal Experiment for Technically Oriented Research (TEXTOR) [R. J. E. Jaspers, Ph.D. thesis, Technical University Eindhoven (1995)] are interpreted in terms of such interaction.

  14. Hybridization between subspecies of waterbuck (Kobus ellipsiprymnus) in zones of overlap with limited introgression

    DEFF Research Database (Denmark)

    Lorenzen, Eline D; Simonsen, Bo T; Kat, Pieter W

    2006-01-01

    if the intermediate populations are the results of hybridization. In total, 186 individuals from 11 localities were analysed. A high degree of genetic differentiation was found between subspecies, although this was most evident from the microsatellite data. Hybridization was suggested in the phenotypically...

  15. Surgeons and suture zones: Hybridization among four surgeonfish species in the Indo-Pacific with variable evolutionary outcomes.

    Science.gov (United States)

    DiBattista, Joseph D; Whitney, Jonathan; Craig, Matthew T; Hobbs, Jean-Paul A; Rocha, Luiz A; Feldheim, Kevin A; Berumen, Michael L; Bowen, Brian W

    2016-08-01

    Closely related species can provide valuable insights into evolutionary processes through comparison of their ecology, geographic distribution and the history recorded in their genomes. In the Indo-Pacific, many reef fishes are divided into sister species that come into secondary contact at biogeographic borders, most prominently where Indian Ocean and Pacific Ocean faunas meet. It is unclear whether hybridization in this contact zone represents incomplete speciation, secondary contact, an evolutionary dead-end (for hybrids) or some combination of the above. To address these issues, we conducted comprehensive surveys of two widely-distributed surgeonfish species, Acanthurus leucosternon (N=141) and A. nigricans (N=412), with mtDNA cytochrome b sequences and ten microsatellite loci. These surgeonfishes are found primarily in the Indian and Pacific Oceans, respectively, but overlap at the Christmas and Cocos-Keeling Islands hybrid zone in the eastern Indian Ocean. We also sampled the two other Pacific members of this species complex, A. achilles (N=54) and A. japonicus (N=49), which are known to hybridize with A. nigricans where their ranges overlap. Our results indicate separation between the four species that range from the recent Pleistocene to late Pliocene (235,000-2.25million years ago). The Pacific A. achilles is the most divergent (and possibly ancestral) species with mtDNA dcorr≈0.04, whereas the other two Pacific species (A. japonicus and A. nigricans) are distinguishable only at a population or subspecies level (ΦST=0.6533, P<0.001). Little population structure was observed within species, with evidence of recent population expansion across all four geographic ranges. We detected sharing of mtDNA haplotypes between species and extensive hybridization based on microsatellites, consistent with later generation hybrids but also the effects of allele homoplasy. Despite extensive introgression, 98% of specimens had concordance between mtDNA lineage and

  16. Surgeons and suture zones: Hybridization among four surgeonfish species in the Indo-Pacific with variable evolutionary outcomes

    KAUST Repository

    DiBattista, Joseph

    2016-04-30

    Closely related species can provide valuable insights into evolutionary processes through comparison of their ecology, geographic distribution and the history recorded in their genomes. In the Indo-Pacific, many reef fishes are divided into sister species that come into secondary contact at biogeographic borders, most prominently where Indian Ocean and Pacific Ocean faunas meet. It is unclear whether hybridization in this contact zone represents incomplete speciation, secondary contact, an evolutionary dead-end (for hybrids) or some combination of the above. To address these issues, we conducted comprehensive surveys of two widely-distributed surgeonfish species, Acanthurus leucosternon (N = 141) and A. nigricans (N = 412), with mtDNA cytochrome b sequences and ten microsatellite loci. These surgeonfishes are found primarily in the Indian and Pacific Oceans, respectively, but overlap at the Christmas and Cocos-Keeling Islands hybrid zone in the eastern Indian Ocean. We also sampled the two other Pacific members of this species complex, A. achilles (N = 54) and A. japonicus (N = 49), which are known to hybridize with A. nigricans where their ranges overlap. Our results indicate separation between the four species that range from the recent Pleistocene to late Pliocene (235,000 to 2.25 million years ago). The Pacific A. achilles is the most divergent (and possibly ancestral) species with mtDNA dcorr ≈ 0.04, whereas the other two Pacific species (A. japonicus and A. nigricans) are distinguishable only at a population or subspecies level (ΦST = 0.6533, P < 0.001). Little population structure was observed within species, with evidence of recent population expansion across all four geographic ranges. We detected sharing of mtDNA haplotypes between species and extensive hybridization based on microsatellites, consistent with later generation hybrids but also the effects of allele homoplasy. Despite extensive introgression, 98% of specimens had concordance between mt

  17. Investigation of the hybrid electron linac with negative group velocity

    Science.gov (United States)

    Savin, E. A.; Alekhanov, R. Yu.; Bulanov, A. V.; Kaminskiy, V. I.; Matsievskiy, S. V.; Sobenin, N. P.

    2016-09-01

    Hybrid accelerator, incorporating travelling wave (TW) and standing wave (SW) structures is proposed and discussed. Accelerator can sum up an RF focusing in the SW buncher and lower losses in the TW accelerating structure walls. Moreover, the structure without dumping load is proposed. Input power and beam loading are chosen to minimize power reflection from buncher maintain travelling wave regime in the accelerating structure while beam loading is on. In this case SW buncher operates as a dumping load, so all input power either goes to beam or dissipates in the wall losses, it increases structure efficiency. RF characteristics and beam dynamics simulations have been performed.

  18. Paired-pulse facilitation achieved in protonic/electronic hybrid indium gallium zinc oxide synaptic transistors

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Li Qiang, E-mail: guoliqiang@ujs.edu.cn; Ding, Jian Ning; Huang, Yu Kai [Micro/Nano Science & Technology Center, Jiangsu University, Zhenjiang, 212013 (China); Zhu, Li Qiang, E-mail: lqzhu@nimte.ac.cn [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2015-08-15

    Neuromorphic devices with paired pulse facilitation emulating that of biological synapses are the key to develop artificial neural networks. Here, phosphorus-doped nanogranular SiO{sub 2} electrolyte is used as gate dielectric for protonic/electronic hybrid indium gallium zinc oxide (IGZO) synaptic transistor. In such synaptic transistors, protons within the SiO{sub 2} electrolyte are deemed as neurotransmitters of biological synapses. Paired-pulse facilitation (PPF) behaviors for the analogous information were mimicked. The temperature dependent PPF behaviors were also investigated systematically. The results indicate that the protonic/electronic hybrid IGZO synaptic transistors would be promising candidates for inorganic synapses in artificial neural network applications.

  19. Rechargeable Mg battery cathode TiS3 with d-p orbital hybridized electronic structures

    Science.gov (United States)

    Taniguchi, Kouji; Gu, Yunpeng; Katsura, Yukari; Yoshino, Takafumi; Takagi, Hidenori

    2016-01-01

    Rechargeable performance is realized in Mg batteries using a TiS3 cathode without the nanometer-scale downsizing of electrode particles. The specific capacity is about 80 mAh/g for the first 50 cycles at room temperature. This observed specific capacity is comparable to that of the prototype cathode for Mg batteries. First-principles calculation indicates that TiS3 is a semiconductor with d-p orbital hybridized electronic structures around the Fermi level. The reversible electrode performance is likely assisted by the delocalized electronic distribution over metal-ligand units through d-p orbital hybridization.

  20. 3D electronics for hybrid pixel detectors – TWEPP-09

    CERN Document Server

    Godiot, S; Chantepie, B; Clémens, J C; Fei, R; Fleury, J; Fougeron, D; Garcia-Sciveres, M; Hemperek, T; Karagounis, M; Krueger, H; Mekkaoui, A; Pangaud, P; Rozanov, A; Wermes, N

    2009-01-01

    Future hybrid pixel detectors are asking for smaller pixels in order to improve spatial resolution and to deal with an increasing counting rate. Facing these requirements is foreseen to be done by microelectronics technology shrinking. However, this straightforward approach presents some disadvantages in term of performances and cost. New 3D technologies offer an alternative way with the advantage of technology mixing. For the upgrade of ATLAS pixel detector, a 3D conception of the read-out chip appeared as an interesting solution. Splitting the pixel functionalities into two separate levels will reduce pixel size and open the opportunity to take benefit of technology's mixing. Based on a previous prototype of the read-out chip FE-I4 (IBM 130nm), this paper presents the design of a hybrid pixel read-out chip using threedimensional Tezzaron-Chartered technology. In order to disentangle effects due to Chartered 130nm technology from effects involved by 3D architecture, a first translation of FEI4 prototype had ...

  1. Habitat association and seasonality in a mosaic and bimodal hybrid zone between Chorthippus brunneus and C. jacobsi (Orthoptera: Acrididae.

    Directory of Open Access Journals (Sweden)

    Richard I Bailey

    Full Text Available Understanding why some hybrid zones are bimodal and others unimodal can aid in identifying barriers to gene exchange following secondary contact. The hybrid zone between the grasshoppers Chorthippus brunneus and C. jacobsi contains a mix of allopatric parental populations and inter-mingled bimodal and unimodal sympatric populations, and provides an ideal system to examine the roles of local selection and gene flow between populations in maintaining bimodality. However, it is first necessary to confirm, over a larger spatial scale, previously identified associations between population composition and season and habitat. Here we use cline-fitting of one morphological and one song trait along two valley transects, and intervening mountains, to confirm previously identified habitat associations (mountain versus valley and seasonal changes in population composition. As expected from previous findings of studies on a smaller spatial scale, C. jacobsi dominated mountain habitats and mixed populations dominated valleys, and C. brunneus became more prevalent in August. Controlling for habitat and incorporating into the analysis seasonal changes in cline parameters and the standard errors of parental trait values revealed wider clines than previous studies (best estimates of 6.4 to 24.5 km in our study versus 2.8 to 4.7 km in previous studies and increased percentage of trait variance explained (52.7% and 61.5% for transects 1 and 2 respectively, versus 17.6%. Revealing such strong and consistent patterns within a complex hybrid zone will allow more focused examination of the causes of variation in bimodality in mixed populations, in particular the roles of local selection versus habitat heterogeneity and gene flow between differentiated populations.

  2. Nanoscale Structure of Self-Assembling Hybrid Materials of Inorganic and Electronically Active Organic Phases

    Energy Technology Data Exchange (ETDEWEB)

    Sofos, M.; Goswami, D.A. Stone D.K.; Okasinski, J.S.; Jin, H.; Bedzyk, M.J.; Stupp, S.I. (NWU)

    2008-10-06

    Hybrid materials with nanoscale structure that incorporates inorganic and organic phases with electronic properties offer potential in an extensive functional space that includes photovoltaics, light emission, and sensing. This work describes the nanoscale structure of model hybrid materials with phases of silica and electronically active bola-amphiphile assemblies containing either oligo(p-phenylene vinylene) or oligo(thiophene) segments. The hybrid materials studied here were synthesized by evaporation-induced self-assembly and characterized by X-ray scattering techniques. Grazing-incidence X-ray scattering studies of these materials revealed the formation of two-dimensional hexagonally packed cylindrical micelles of the organic molecules with diameters between 3.1 and 3.6 nm and cylindrical axes parallel to the surface. During the self-assembly process at low pH, the cylindrical aggregates of conjugated molecules become surrounded by silica giving rise to a hybrid structure with long-range order. Specular X-ray reflectivity confirmed the long-range periodicity of the hybrid films within a specific range of molar ratios of tetraethyl orthosilicate to cationic amphiphile. We did not observe any long-range ordering in fully organic analogues unless quaternary ammonium groups were replaced by tertiary amines. These observations suggest that charge screening in these biscationic conjugated molecules by the mineral phase is a key factor in the evolution of long range order in the self-assembling hybrids.

  3. Connection Capacity of the Transition Zone in Steel-Concrete Hybrid Beam

    Directory of Open Access Journals (Sweden)

    Kozioł Piotr

    2017-06-01

    Full Text Available The problem of transition zone of structural steel element connected to concrete is discussed in the following paper. This zone may be located for instance in specific bridge composite girder. In such case the composite beam passes smoothly into concrete beam. Because of several dowels usage in the transition zone, the problem of uneven force distribution were discussed through analogy to bolted and welded connections. The authors present innovative solution of transition zone and discuss the results, with emphasis put on the transition zone structural response in term of bending capacity, failure model and force distribution on the connection length. The article wider the already executed experimental test and presents its newest results.

  4. The electronic transport characteristics of hybridized hexagon beryllium sulfide and graphene nanoribbons

    Science.gov (United States)

    Wang, Lihua; Ding, Bingjun; Guo, Yong

    2017-01-01

    Hybridized Z-BexSyCz (x + y + z = 16) systems connected by zigzag beryllium-sulfide (BeS) and graphene nanoribbons are theoretically designed, and their electronic transport characteristics are explored by first-principles approach. For the hybridized systems with unequal number of x and y, i.e. z is an odd number, an exceptional negative differential resistance (NDR) property occurs. However, for the hybridized systems including an even number of zigzag carbon chains, namely x equal to y, an interesting current-limited behavior happens. Meanwhile, the NDR phenomenon disappears. The spin transport properties of these hybridized Z-BexSyCz systems with parallel magnetism configuration also reveal the above odd-even dependence conductance behavior.

  5. Using k-alpha emission to determine fast electron spectra using the Hybrid code ZEPHYROS

    CERN Document Server

    White, Thomas; Gregori, Gianluca

    2014-01-01

    A high intensity laser-solid interaction invariably drives a non-thermal fast electron current through the target, however characterizing these fast electron distributions can prove difficult. An understanding of how these electrons propagate through dense materials is of fundamental interest and has applications relevant to fast ignition schemes and ion acceleration. Here, we utilize an upgraded version of the Hybrid code ZEPHYROS to demonstrate how the resulting k-alpha emission from such an interaction can be used as a diagnostic to obtain the characteristic temperature, divergence and total energy of the fast electron population.

  6. My ENG 102 Class Has Gone to HEC: Creating the Hybrid Electronic Course.

    Science.gov (United States)

    Ross, Jeffrey

    In this paper, a college English professor shares his teaching experiences in a Hybrid Electronic Course (HEC), which combined traditional classroom meetings with e-mail-based workshops. The paper includes a general description of the course, the instructor's daily journals throughout the course, and his reflections following the course. Many of…

  7. Oxide nanomembrane hybrids with enhanced mechano- and thermo-sensitivity for semitransparent epidermal electronics.

    Science.gov (United States)

    Park, Minjoon; Do, Kyungsik; Kim, Jaemin; Son, Donghee; Koo, Ja Hoon; Park, Jinkyung; Song, Jun-Kyul; Kim, Ji Hoon; Lee, Minbaek; Hyeon, Taeghwan; Kim, Dae-Hyeong

    2015-05-01

    Oxide nanomembrane hybrids with enhanced mechano- and thermo-sensitivity for semitransparent epidermal electronics are developed. The use of nanomaterials (single wall nanotubes and silver nanoparticles) embedded in the oxide nanomembranes significantly enhances mechanical and thermal sensitivities. These mechanical and thermal sensors are utilized in wheelchair control and hypothermia detection, which are useful for patients with strokes.

  8. Bosch automotive electrics and automotive electronics systems and components, networking and hybrid drive

    CERN Document Server

    2014-01-01

    The significance of electrical and electronic systems has increased considerably in the last few years and this trend is set to continue. The characteristics feature of innovative systems is the fact that they can work together in a network. This requires powerful bus systems that the electronic control units can use to exchange information. Networking and the various bus systems used in motor vehicles are the prominent new topic in the 5th edition of the "Automotive Electric, Automotive Electronics" technical manual. The existing chapters have also been updated, so that this new edition brings the reader up to date on the subjects of electrical and electronic systems in the motor vehicle. Content Electrical and electronical systems – Basic principles of networking - Examples of networked vehicles – Bus systems – Architecture of electronic systems – Mechatronics – Elektronics – Electronic control Units – Software – Sensors – Actuators – Hybrid drives – Vehicle electrical system – Start...

  9. Shoot Photosynthesis and Root Growth of Hybrid and Conventional Rice Cultivars as Affected by N and K Levels in the Root Zone

    Institute of Scientific and Technical Information of China (English)

    YANGXIAOE; V.ROEMHELD; 等

    1997-01-01

    Root box experiments were conducted to evaluate the effects of N and NK levels in the root zone on shoot photosynthesis and root growth of hybrid an cultivar of rice (Oryza sativa L.) on two paddy soils (clayey and silty).The results showed that dry matter yields in the hybrid and the cultivar were considerably increased by NK supply,bu the effect was greater for the hybrid.Supply of NK in the root zone significantly increased photosynthetic rate of the lower position leaf and the active green leaf area per plant,in which the effects were much more obvious in the hybrid rice than in the cultivar.High NK supply in the root zone stimulated the root growth,and decreased pH and increased the oxidation zone in the rhizosphere in both entries,but to a greater extent in the hybrid .The results indicated that higher NK levels were needed to maintain higher root activity and shoot photosynthetic capacity in rice,particularly in hybrid rice.

  10. New materials strategies for creating hybrid electronic circuitry (Presentation Video)

    Science.gov (United States)

    Marks, Tobin J.

    2013-09-01

    This lecture focuses on the challenging design and realization of new materials for creating unconventional electronic circuitry. Fabrication methodologies to achieve these goals include high-throughput, large-area printing techniques. Materials design topics to be discussed include: 1. Rationally designed high-mobility p- and n-type organic semiconductors for printed organic CMOS, 2. Polycrystalline and amorphous oxide semiconductors for transparent and mechanically flexible electronics, 3) Self-assembled and printable high-k nanodielectrics enabling ultra-large capacitance, low leakage, high breakdown fields, minimal trapped interfacial charge, and device radiation hardness. 4) Combining these materials sets to fabricate a variety of high-performance thin-film transistor-based devices.

  11. Electronic Structure Rearrangements in Hybrid Ribozyme/Protein Catalysis

    Science.gov (United States)

    Kang, Jiyoung; Kino, Hiori; Field, Martin J.; Tateno, Masaru

    2017-04-01

    We analyzed the electronic structural changes that occur in the reaction cycle of a biological catalyst composed of RNA and protein, and elucidated the dynamical rearrangements of the electronic structure that was obtained from our previous study in which ab initio quantum mechanics/molecular mechanics molecular dynamics simulations were performed. Notable results that we obtained include the generation of a reactive HOMO that is responsible for bond formation in the initial stages of the reaction, and the appearance of a reactive LUMO that is involved in the bond rupture that leads to products. We denote these changes as dynamical induction of the reactive HOMO (DIRH) and LUMO (DIRL), respectively. Interestingly, we also find that the induction of the reactive HOMO is enhanced by the formation of a low-barrier hydrogen bond (LBHB), which, to the best of our knowledge, represents a novel role for LBHBs in enzymatic systems.

  12. Hybrid optical and electronic laser locking using spectral hole burning

    CERN Document Server

    Farr, Warrick G; Ledingham, Patrick M; Korystov, Dmitry; Longdell, Jevon J

    2010-01-01

    We report on a narrow linewidth laser diode system that is stabilized using both optical and electronic feedback to a spectral hole in cryogenic Tm:YAG. The laser system exhibits very low phase noise. The spectrum of the beat signal between two lasers, over millisecond timescales, is either Fourier limited or limited by the -111dBc/Hz noise floor. The resulting laser is well suited to quantum optics and sensing applications involving rare earth ion dopants.

  13. 75 FR 53638 - Approval for Manufacturing Authority; Foreign-Trade Zone 22; LG Electronics Mobilecomm USA, Inc...

    Science.gov (United States)

    2010-09-01

    ... Manufacturing Authority; Foreign-Trade Zone 22; LG Electronics Mobilecomm USA, Inc. (Cell Phone Kitting and... manufacturing authority on behalf of LG Electronics Mobilecomm USA, Inc. (LGEMU), within FTZ 22 in Bolingbrook... Electronics Mobilecomm USA, Inc., as described in the application and Federal Register notice, is...

  14. Transmission electron microscopy of unstained hybrid Au nanoparticles capped with PPAA (plasma-poly-allylamine): structure and electron irradiation effects.

    Science.gov (United States)

    Gontard, Lionel C; Fernández, Asunción; Dunin-Borkowski, Rafal E; Kasama, Takeshi; Lozano-Pérez, Sergio; Lucas, Stéphane

    2014-12-01

    Hybrid (organic shell-inorganic core) nanoparticles have important applications in nanomedicine. Although the inorganic components of hybrid nanoparticles can be characterized readily using conventional transmission electron microscopy (TEM) techniques, the structural and chemical arrangement of the organic molecular components remains largely unknown. Here, we apply TEM to the physico-chemical characterization of Au nanoparticles that are coated with plasma-polymerized-allylamine, an organic compound with the formula C3H5NH2. We discuss the use of energy-filtered TEM in the low-energy-loss range as a contrast enhancement mechanism for imaging the organic shells of such particles. We also study electron-beam-induced crystallization and amorphization of the shells and the formation of graphitic-like layers that contain both C and N. The resistance of the samples to irradiation by high-energy electrons, which is relevant for optical tuning and for understanding the degree to which such hybrid nanostructures are stable in the presence of biomedical radiation, is also discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Vive la résistance: genome-wide selection against introduced alleles in invasive hybrid zones.

    Science.gov (United States)

    Kovach, Ryan P; Hand, Brian K; Hohenlohe, Paul A; Cosart, Ted F; Boyer, Matthew C; Neville, Helen H; Muhlfeld, Clint C; Amish, Stephen J; Carim, Kellie; Narum, Shawn R; Lowe, Winsor H; Allendorf, Fred W; Luikart, Gordon

    2016-11-30

    Evolutionary and ecological consequences of hybridization between native and invasive species are notoriously complicated because patterns of selection acting on non-native alleles can vary throughout the genome and across environments. Rapid advances in genomics now make it feasible to assess locus-specific and genome-wide patterns of natural selection acting on invasive introgression within and among natural populations occupying diverse environments. We quantified genome-wide patterns of admixture across multiple independent hybrid zones of native westslope cutthroat trout and invasive rainbow trout, the world's most widely introduced fish, by genotyping 339 individuals from 21 populations using 9380 species-diagnostic loci. A significantly greater proportion of the genome appeared to be under selection favouring native cutthroat trout (rather than rainbow trout), and this pattern was pervasive across the genome (detected on most chromosomes). Furthermore, selection against invasive alleles was consistent across populations and environments, even in those where rainbow trout were predicted to have a selective advantage (warm environments). These data corroborate field studies showing that hybrids between these species have lower fitness than the native taxa, and show that these fitness differences are due to selection favouring many native genes distributed widely throughout the genome. © 2016 The Author(s).

  16. Microgeographic allozyme differentiation in the hybrid zone of Mytilus galloprovincialis Lmk. and M. edulis L. on the continental European coast

    Science.gov (United States)

    Comesaña, A. S.; Sanjuan, A.

    1997-03-01

    The European Mytilus galloprovincialis Lmk. and M. edulis L. coexist and hybridize in different proportions in extended areas of the British and Atlantic French coasts. M. galloprovincialis typical allozymes seem to predominate in wave exposed areas, at high levels of attachment and in larger mussels in the British hybrid zone. Mussel samples from exposed and sheltered areas, 200 m apart, and from high and low levels of attachment were collected from a location of the French hybrid zone in 1988 92. Pure M. galloprovincialis and M. edulis populations were also taken as controls. Diagnostic enzyme loci for both Mytilus (EST-D *, LAP-1*, MPI*, ODH*) and AP-1 *, LAP-2* and PGM * loci were studied. The frequencies of the M. galloprovincialis typical alleles were significantly greater in exposed populations than in sheltered samples (e.g. 0.729 to 0.803 vs 0.192 to 0.581 for EST-D *90), and at high level of attachment than at low level for the sheltered area (e.g. 0.581 vs 0.192 for EST-D *90). Putative M. galloprovincialis was more abundant on the exposed coast (0.591 and 0.702) than on the sheltered shore, where it predominated at the high shore but not at the low shore location (0.371 vs 0.045). Significantly positive correlations between shell length and typical M. galloprovincialis compound allele frequencies were found only for populations from exposed areas. Relationships between the Mytilus genetic differentiation and ecological factors are discussed.

  17. Hybridized electromagnetic-triboelectric nanogenerator for scavenging biomechanical energy for sustainably powering wearable electronics.

    Science.gov (United States)

    Zhang, Kewei; Wang, Xue; Yang, Ya; Wang, Zhong Lin

    2015-01-01

    We report a hybridized electromagnetic-triboelectric nanogenerator for highly efficient scavenging of biomechanical energy to sustainably power wearable electronics by human walking. Based on the effective conjunction of triboelectrification and electromagnetic induction, the hybridized nanogenerator, with dimensions of 5 cm × 5 cm × 2.5 cm and a light weight of 60 g, integrates a triboelectric nanogenerator (TENG) that can deliver a peak output power of 4.9 mW under a loading resistance of 6 MΩ and an electromagnetic generator (EMG) that can deliver a peak output power of 3.5 mW under a loading resistance of 2 kΩ. The hybridized nanogenerator exhibits a good stability for the output performance and a much better charging performance than that of an individual energy-harvesting unit (TENG or EMG). Furthermore, the hybridized nanogenerator integrated in a commercial shoe has been utilized to harvest biomechanical energy induced by human walking to directly light up tens of light-emitting diodes in the shoe and sustainably power a smart pedometer for reading the data of a walking step, distance, and energy consumption. A wireless pedometer driven by the hybrid nanogenerator can work well to send the walking data to an iPhone under the distance of 25 m. This work pushes forward a significant step toward energy harvesting from human walking and its potential applications in sustainably powering wearable electronics.

  18. First-Principles Study of Electronic Structure of Type I Hybrid Carbon-Silicon Clathrates

    Science.gov (United States)

    Chan, Kwai S.; Peng, Xihong

    2016-08-01

    A new class of type I hybrid carbon-silicon clathrates has been designed using computational methods by substituting some of the Si atoms in the silicon clathrate framework with carbon atoms. In this work, the electronic structure of hybrid carbon-silicon clathrates with and without alkaline or alkaline-earth metal guest atoms has been computed within the density functional theory framework. The theoretical calculations indicate that a small number of carbon substitutions in the Si46 framework slightly reduces the density of states (DOS) near the band edge and narrows the bandgap of carbon-silicon clathrates. Weak hybridization of the conduction band occurs when alkaline metal (Li, Na, K) atoms are inserted into the structure, while strong hybridization of the conduction band occurs when alkaline-earth metal (Mg, Ca, Ba) atoms are inserted into the hybrid structure. Empty C y Si46- y clathrates within the composition range of 2 ≤ y ≤ 15 can be tuned to exhibit indirect bandgaps of 1.5 eV or less, and may be considered as potential electronic materials.

  19. Mode conversion and electron heating near the upper hybrid resonance frequency

    Energy Technology Data Exchange (ETDEWEB)

    Smith, B.L.; Okuda, H.; Abe, H.

    1983-11-01

    Mode conversion near the upper hybrid resonance frequency and electron heating are studied using a one-dimensional electromagnetic relativistic particle code. It is found that for a sufficiently small pump field E/sub 0/, E/sub 0//sup 2//4..pi..nT/sub e/ less than or equal to 0.01, electron heating is localized in a region near the electron cyclotron layer where the pump frequency is equal to the local electron gyrofrequency. For stronger pump fields, electron heating takes place more or less uniformly across a region between the upper hybrid resonance layer and the cyclotron layer. In addition, a significant fraction of electromagnetic energy associated with the pump is found to be reflected back into the vacuum from a region in the plasma near the upper hybrid resonance layer for both strong (E/sub 0//sup 2//4..pi..nT/sub e/ approx. = 1) and weak pumps (E/sub 0//sup 2//4..pi..nT/sub e/ << 1).

  20. Electron distribution function behavior during localized transverse ion acceleration events in the topside auroral zone

    Energy Technology Data Exchange (ETDEWEB)

    Lynch, K.A.; Arnoldy, R.L. [Univ. of New Hampshire, Durham, NH (United States); Kintner, P.M. [Cornell Univ., Ithaca, NY (United States); Vago, J.L. [European Space Agency, Noordwijk (Netherlands)

    1994-02-01

    The Topaz3 auroral sounding rocket made the following observations concerning the transfer of precipitating auroral electron energy to transverse ion acceleration in the topside auroral zone. During the course of the flight, the precipitating electron beam was modified to varying degrees by interaction with VLF hiss, at times changing the beam into a field-aligned plateau. The electron distribution functions throughout the flight are classified according to the extent of this modification, and correspondences with ion acceleration events are sought. The hiss power during most of this rocket flight apparently exceeded the threshold for collapse into solitary structures. At the times of plateaued electron distributions, the collapse of these structures was limited by Landau damping through the ambient ions, resulting in a velocity-dependent acceleration of both protons and oxygen. This initial acceleration is sufficient to supply the number flux of upflowing ions observed at satellite altitudes. The bursty ion acceleration was anticorrelated, on 1-s or smaller timescales, with dispersive bursts of precipitating field-aligned electrons, although on longer timescales the bursty ions and the bursty electrons are correlated. 45 refs., 9 figs.

  1. Power electronics and electric machinery challenges and opportunities in electric and hybrid vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Adams, D.J.; Hsu, J.S.; Young, R.W. [Oak Ridge National Lab., TN (United States); Peng, F.Z. [Univ. of Tennessee, Knoxville, TN (United States)

    1997-06-01

    The development of power electronics and electric machinery presents significant challenges to the advancement of electric and hybrid vehicles. Electronic components and systems development for vehicle applications have progressed from the replacement of mechanical systems to the availability of features that can only be realized through interacting electronic controls and devices. Near-term applications of power electronics in vehicles will enable integrated powertrain controls, integrated chassis system controls, and navigation and communications systems. Future applications of optimized electric machinery will enable highly efficient and lightweight systems. This paper will explore the areas where research and development is required to ensure the continued development of power electronics and electric machines to meet the rigorous demands of automotive applications. Additionally, recent advances in automotive related power electronics and electric machinery at Oak Ridge National Laboratory will be explained. 3 refs., 5 figs.

  2. A review and design of power electronics converters for fuel cell hybrid system applications

    DEFF Research Database (Denmark)

    Zhang, Zhe; Pittini, Riccardo; Andersen, Michael A. E.

    2012-01-01

    This paper presents an overview of most promising power electronics topologies for a fuel cell hybrid power conversion system which can be utilized in many applications such as hybrid electrical vehicles (HEV), distributed generations (DG) and uninterruptible-power-supply (UPS) systems. Then......, a multiple-input power conversion system including a decoupled dual-input converter and a three-phase neutral-point-clamped (NPC) inverter is proposed. The system can operate in both stand-alone and grid-connected modes. Simulation and experimental results are provided to show the feasibility of the proposed...

  3. Efficient Hybrid Optimal Design Method for Power Electronics Converters

    CERN Document Server

    AUTHOR|(SzGeCERN)697719; Aguglia, Davide; Viarouge, Philippe; Cros, Jérôme

    2015-01-01

    This paper presents a novel design methodology for dimensioning optimal power-electronic converters, which is able to achieve the precision of numerical simulation-based optimization procedures, however minimizing the overall computation time. The approach is based on the utilization of analytical and frequency-domain design models for a numerical optimization process, a validation with numerical simulations of the intermediate optimal solutions, and the correction of the analytical design models precision from the numerical simulation results. This method allows using the numerical simulation in an efficient way, where typically less than ten correction iterations are required. In order to demonstrate the performances of the proposed methodology, the calculation of the control parameters for an H-bridge DC-DC converter and the optimal dimensioning of a damped output filter for a buck converter using the proposed approach is presented.

  4. Electronic and magnetic properties of modified silicene/graphene hybrid: Ab initio study

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Suman; Jana, Debnarayan, E-mail: cujanad@yahoo.com

    2016-11-01

    Among other two-dimensional (2D) novel materials, graphene and silicene both have drawn intense research interest among the researchers because they possess some unique intriguing properties which can change the scenario of the current electronic industry. In this work we have studied the electronic and the magnetic properties of a new kind of materials which is the hybrid of these two materials. Density functional theory (DFT) has been employed to calculate the relevant electronic and magnetic properties of this hybrid material. The pristine structure is modified by substitutional doping or by creating vacancy (Y-X, where one Y atom (Si or C) has been replaced by one X atom (B, N, Al, P or void)). The calculations have revealed that void systems are unstable while Si-B and Si-N are most stable ones. It has been noticed that some of these doped structures are magnetic in nature having induced mid-gap states in the system. In particular, Si-void structure is unstable yet it possess the highest magnetic moment of the order of 4 μ{sub B} (μ{sub B} being the Bohr magneton). The estimated band gaps of modified silicene/graphene hybrid from spin polarized partial density of states (PDOS) vary between 1.43–2.38 eV and 1.58–2.50 eV for spin-up and spin-down channel respectively. The implication of midgap states has been critically analysed in the light of magnetic nature. This study may be useful to build hybrid spintronic devices with controllable gap for spin up and spin down states. - Graphical abstract: We have studied the electronic and magnetic properties of silicene/graphene hybrid by employing density functional theory (DFT). - Highlights: • Electronic and magnetic properties of two dimensional graphene/silicene hybrid have been explored. • There is no magnetism in the system for a single carbon atom vacancy. • A net magnetic moment of 4.0 Bohr magneton is observed for a single silicon atom vacancy. • Unpaired electrons introduce mid-gap states which

  5. A hybrid model of swash-zone longshore sediment transport on refelctive beaches

    NARCIS (Netherlands)

    Jiang, A.W.; Hughes, M.; Cowell, P.; Gordon, A.; Savioli, J.C.; Ranasinghe, R.W.M.R.J.B.

    2010-01-01

    The hydrodynamics and sediment transport in the swash zone is currently outside the domain of coastal-area models, which is a significant limitation in obtaining littoral sediment-transport estimates, especially on steep reflective beaches where the waves practically break on the beachface. In this

  6. A hybrid model of swash-zone longshore sediment transport on refelctive beaches

    NARCIS (Netherlands)

    Jiang, A.W.; Hughes, M.; Cowell, P.; Gordon, A.; Savioli, J.C.; Ranasinghe, R.W.M.R.J.B.

    2010-01-01

    The hydrodynamics and sediment transport in the swash zone is currently outside the domain of coastal-area models, which is a significant limitation in obtaining littoral sediment-transport estimates, especially on steep reflective beaches where the waves practically break on the beachface. In this

  7. Study of macro- and micro-segregation of iridium in molybdenum single crystals after electron beam zone melting

    Energy Technology Data Exchange (ETDEWEB)

    Drapala, Jaromir; Skotnicova, Katerina [VSB-Technical University of Ostrava (Czech Republic). Dept. of Non-ferrous Metals, Refining and Recycling

    2013-01-15

    The aim of the work was to study the creation of micro- and macro-segregation of iridium in low-alloyed molybdenum single crystals after electron beam zone melting (floating zone technique) depending on various conditions of crystallization. In order to evaluate relations between the chemical inhomogeneity and structural defects and their influence on properties of single crystals, the dependence of concentration and character of distribution of admixtures under various crystallization conditions on the origin of concentration undercooling and dislocation substructure of molybdenum single crystals prepared by electron beam floating zone melting was experimentally investigated.

  8. Hybridized Electromagnetic-Triboelectric Nanogenerator for a Self-Powered Electronic Watch.

    Science.gov (United States)

    Quan, Ting; Wang, Xue; Wang, Zhong Lin; Yang, Ya

    2015-12-22

    We report a hybridized nanogenerator including a triboelectric nanogenerator (TENG) and six electromagnetic generators (EMGs) that can effectively scavenge biomechanical energy for sustainably powering an electronic watch. Triggered by the natural motions of the wearer's wrist, a magnetic ball at the center in an acrylic box with coils on each side will collide with the walls, resulting in outputs from both the EMGs and the TENG. By using the hybridized nanogenerator to harvest the biomechanical energy, the electronic watch can be continuously powered under different motion types of the wearer's wrist, where the best approach is to charge a 100 μF capacitor in 39 s to maintain the continuous operation of the watch for 456 s. To increase the working time of the watch further, a homemade Li-ion battery has been utilized as the energy storage unit for realizing the continuous working of the watch for about 218 min by using the hybridized nanogenerator to charge the battery within 32 min. This work will provide the opportunities for developing a nanogenerator-based built-in power source for self-powered wearable electronics such as an electronic watch.

  9. Photoionization of few electron systems with a hybrid Coupled Channels approach

    CERN Document Server

    Majety, Vinay Pramod; Scrinzi, Armin

    2014-01-01

    We present the hybrid anti-symmetrized coupled channels method for the calculation of fully differential photo-electron spectra of multi-electron atoms and small molecules interacting with strong laser fields. The method unites quantum chemical few-body electronic structure with strong-field dynamics by solving the time dependent Schr\\"odinger equation in a fully anti-symmetrized basis composed of multi-electron states from quantum chemistry and a one-electron numerical basis. Photoelectron spectra are obtained via the time dependent surface flux (tSURFF) method. Performance and accuracy of the approach are demonstrated for spectra from the helium and berryllium atoms and the hydrogen molecule in linearly polarized laser fields at wavelength from 21 nm to 400 nm. At long wavelengths, helium and the hydrogen molecule at equilibrium inter-nuclear distance can be approximated as single channel systems whereas beryllium needs a multi-channel description.

  10. Adaptability of grades and hybrids of tangerine in a subtropical zone of Russia

    OpenAIRE

    Julia Abilphazova; Oksana Belous

    2015-01-01

    Results of researches of various cultivars and hybrids of tangerine growing in the conditions of the humid subtropics of Russia and possessing valuable physiological and biochemical markers are presented in article. The stress factors limiting cultivation of tangerine culture in Krasnodar region are defined. The assessment of the water saving and enzymes activity in tangerine leaves is given. Changes of physiological parameters at influence of a stressful factor are shown. The analysis of wat...

  11. Energy‐dependent dynamics of keV to MeV electrons in the inner zone, outer zone, and slot regions

    Science.gov (United States)

    Friedel, Reiner H. W.; Larsen, Brian A.; Skoug, Ruth M.; Funsten, Herbert O.; Claudepierre, Seth G.; Fennell, Joseph F.; Turner, Drew L.; Denton, Mick H.; Spence, Harlan E.; Blake, J. Bernard; Baker, Daniel N.

    2016-01-01

    Abstract We present observations of the radiation belts from the Helium Oxygen Proton Electron and Magnetic Electron Ion Spectrometer particle detectors on the Van Allen Probes satellites that illustrate the energy dependence and L shell dependence of radiation belt enhancements and decays. We survey events in 2013 and analyze an event on 1 March in more detail. The observations show the following: (a) at all L shells, lower energy electrons are enhanced more often than higher energies; (b) events that fill the slot region are more common at lower energies; (c) enhancements of electrons in the inner zone are more common at lower energies; and (d) even when events do not fully fill the slot region, enhancements at lower energies tend to extend to lower L shells than higher energies. During enhancement events the outer zone extends to lower L shells at lower energies while being confined to higher L shells at higher energies. The inner zone shows the opposite with an outer boundary at higher L shells for lower energies. Both boundaries are nearly straight in log(energy) versus L shell space. At energies below a few 100 keV, radiation belt electron penetration through the slot region into the inner zone is commonplace, but the number and frequency of “slot filling” events decreases with increasing energy. The inner zone is enhanced only at energies that penetrate through the slot. Energy‐ and L shell‐dependent losses (that are consistent with whistler hiss interactions) return the belts to more quiescent conditions.

  12. Vehicle height and posture control of the electronic air suspension system using the hybrid system approach

    Science.gov (United States)

    Sun, Xiaoqiang; Cai, Yingfeng; Chen, Long; Liu, Yanling; Wang, Shaohua

    2016-03-01

    The electronic air suspension (EAS) system can improve ride comfort, fuel economy and handling safety of vehicles by adjusting vehicle height. This paper describes the development of a novel controller using the hybrid system approach to adjust the vehicle height (height control) and to regulate the roll and pitch angles of the vehicle body during the height adjustment process (posture control). The vehicle height adjustment system of EAS poses challenging hybrid control problems, since it features different discrete modes of operation, where each mode has an associated linear continuous-time dynamic. In this paper, we propose a novel approach to the modelling and controller design problem for the vehicle height adjustment system of EAS. The system model is described firstly in the hybrid system description language (HYSDEL) to obtain a mixed logical dynamical (MLD) hybrid model. For the resulting model, a hybrid model predictive controller is tuned to improve the vehicle height and posture tracking accuracy and to achieve the on-off statuses direct control of solenoid valves. The effectiveness and performance of the proposed approach are demonstrated by simulations and actual vehicle tests.

  13. A rare case of a natural contact zone in Morocco between an autopolyploid and an allopolyploid of Centaurea aspera with sterile tetraploid hybrids.

    Science.gov (United States)

    Garmendia, A; Ferriol, M; Juarez, J; Zając, A; Kałużny, K; Merle, H

    2015-05-01

    A new contact zone between Centaurea aspera and Centaurea seridis was found in Morocco. Chromosome counts and flow cytometry showed that both taxa were tetraploid (4x = 44). A literature review and morphometric analysis established that C. aspera corresponds to the autopolyploid C. aspera subsp. gentilii and C. seridis corresponds to the allopolyploid C. seridis var. auriculata. This contact area was compared with the homologous contact zones in Spain formed by the diploid C. aspera subsp. stenophylla and the tetraploid C. seridis subsp. maritima. Natural hybrids between parental species were frequent in both areas. In Spain, hybrids were triploid (from reduced gametes A and gamete AB), highly sterile and exerted a 'triploid block'. In Morocco, cytometry showed that hybrids were tetraploid and, therefore, probably fertile, but all the capitula lacked achenes. It is likely that the resulting genome of the new tetraploid hybrid (AAAB), through the fusion of reduced gametes AA (from subsp. gentilii) and AB (from var. auriculata), could explain irregularities in meiosis through formation of aneuploid gametes and, therefore, infertility of the hybrid. Moroccan sterile tetraploid hybrids develop, but have the identical irregularities to Spanish triploids, probably due to the odd number of homologous chromosomes. The new hybrid is first described as C. x subdecurrens nothosubsp. paucispinus. In addition, distribution and ecological traits are analysed.

  14. Hybrid quantum circuit with a superconducting qubit coupled to an electron spin ensemble

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Yuimaru; Grezes, Cecile; Vion, Denis; Esteve, Daniel; Bertet, Patrice [Quantronics Group, SPEC (CNRS URA 2464), CEA-Saclay, 91191 Gif-sur-Yvette (France); Diniz, Igor; Auffeves, Alexia [Institut Neel, CNRS, BP 166, 38042 Grenoble (France); Isoya, Jun-ichi [Research Center for Knowledge Communities, University of Tsukuba, 305-8550 Tsukuba (Japan); Jacques, Vincent; Dreau, Anais; Roch, Jean-Francois [LPQM (CNRS, UMR 8537), Ecole Normale Superieure de Cachan, 94235 Cachan (France)

    2013-07-01

    We report the experimental realization of a hybrid quantum circuit combining a superconducting qubit and an ensemble of electronic spins. The qubit, of the transmon type, is coherently coupled to the spin ensemble consisting of nitrogen-vacancy (NV) centers in a diamond crystal via a frequency-tunable superconducting resonator acting as a quantum bus. Using this circuit, we prepare arbitrary superpositions of the qubit states that we store into collective excitations of the spin ensemble and retrieve back into the qubit. We also report a new method for detecting the magnetic resonance of electronic spins at low temperature with a qubit using the hybrid quantum circuit, as well as our recent progress on spin echo experiments.

  15. Theoretical investigation of the electronic structures and carrier transport of hybrid graphene and boron nitride nanostructure

    Directory of Open Access Journals (Sweden)

    Jia-Tao Sun

    2012-09-01

    graphene and hexagonal boron nitride (C-BN nanostructures receive much research interest due to the complementary electronic properties. Graphene is a zero-gap semiconductor, while hexagonal boron nitride (h-BN is a wide gap semiconductor. Here we studied the electronic structures and carrier transport of hybrid C-BN nanostructures by using first principles calculations and deformation potential theory. We have found that the physical quantities in these systems under study, band gap, effective mass, deformation potential, and carrier mobility, can be categorised into three different families depending on the width of graphene nanoribbon. This family behavior is similar to pristine armchair graphene nanoribbon, but with slight difference from the individual component. New opportunities of designing nanoelectric devices are discussed by utilizing the quantum confinement effect based on such kind of hybrid nanostructures.

  16. Research Update: The electronic structure of hybrid perovskite layers and their energetic alignment in devices

    Directory of Open Access Journals (Sweden)

    Selina Olthof

    2016-09-01

    Full Text Available In recent years, the interest in hybrid organic–inorganic perovskites has increased at a rapid pace due to their tremendous success in the field of thin film solar cells. This area closely ties together fundamental solid state research and device application, as it is necessary to understand the basic material properties to optimize the performances and open up new areas of application. In this regard, the energy levels and their respective alignment with adjacent charge transport layers play a crucial role. Currently, we are lacking a detailed understanding about the electronic structure and are struggling to understand what influences the alignment, how it varies, or how it can be intentionally modified. This research update aims at giving an overview over recent results regarding measurements of the electronic structure of hybrid perovskites using photoelectron spectroscopy to summarize the present status.

  17. Hybrid simulation of whistler excitation by electron beams in two-dimensional non-periodic domains

    Energy Technology Data Exchange (ETDEWEB)

    Woodroffe, J.R., E-mail: woodrofj@erau.edu; Streltsov, A.V., E-mail: streltsa@erau.edu

    2014-11-01

    We present a two-dimensional hybrid fluid-PIC scheme for the simulation of whistler wave excitation by relativistic electron beams. This scheme includes a number of features which are novel to simulations of this type, including non-periodic boundary conditions and fresh particle injection. Results from our model suggest that non-periodicity of the simulation domain results in the development of fundamentally different wave characteristics than are observed in periodic domains.

  18. Role of Microstructure in the Electron-Hole Interaction of Hybrid Lead-Halide Perovskites

    OpenAIRE

    Grancini, Giulia; Srimath Kandada, Ajay Ram; Frost, Jarvist M.; Barker, Alex J; Bastiani, Michele; Gandini, Marina; Marras, Sergio; Lanzani, Guglielmo; Walsh, Aron; Petrozza, Annamaria

    2015-01-01

    Solar cells based on hybrid inorganic-organic halide perovskites have demonstrated high power conversion efficiencies in a range of architectures. The existence and stability of bound electron-hole pairs in these materials, and their role in the exceptional performance of optoelectronic devices, remains a controversial issue. Here we demonstrate, through a combination of optical spectroscopy and multiscale modeling as a function of the degree of polycrystallinity and temperature, that the ele...

  19. The superatom states of fullerenes and their hybridization into the nearly free electron bands of fullerites.

    Science.gov (United States)

    Zhao, Jin; Feng, Min; Yang, Jinlong; Petek, Hrvoje

    2009-04-28

    Motivated by the discovery of the superatom states of C60 molecules, we investigate the factors that influence their energy and wave function hybridization into nearly free electron bands in molecular solids. As the n = 3 solutions of the radial Schrodinger equation of the central attractive potential consisting of the short-range C atom core and the long-range collective screening potentials, respectively, located on the icosahedral C60 molecule shell and within its hollow core, superatom states are distinguished by their atom-like orbitals corresponding to different orbital angular momentum states (l = 0, 1, 2,...). Because they are less tightly bound than the pi orbitals, that is, the n = 2 states, which are often exploited in the intermolecular electron transport in aromatic organic molecule semiconductors, superatom orbitals hybridize more extensively among aggregated molecules to form bands with nearly free electron dispersion. The prospect of exploiting the strong intermolecular coupling to achieve metal-like conduction in applications such as molecular electronics may be attained by lowering the energy of superatom states from 3.5 eV for single chemisorbed C60 molecules to below the Fermi level; therefore, we study how the superatom state energies depend on factors such as their aggregation into 1D-3D solids, cage size, and exo- and endohedral doping by metal atoms. We find, indeed, that if the ionization potential of endohedral atom, such as copper, is sufficiently large, superatom states can form the conduction band in the middle of the gap between the HOMO and LUMO of the parent C60 molecule. Through a plane-wave density functional theory study, we provide insights for a new paradigm for intermolecular electronic interaction beyond the conventional one among the sp(n) hybridized orbitals of the organic molecular solids that could lead to design of novel molecular materials and quantum structures with extraordinary optical and electronic properties.

  20. Relationships between spatio-temporal environmental and genetic variation reveal an important influence of exogenous selection in a pupfish hybrid zone.

    Science.gov (United States)

    Carson, Evan W; Tobler, Michael; Minckley, W L; Ainsworth, Ryan J; Dowling, Thomas E

    2012-03-01

    The importance of exogenous selection in a natural hybrid zone between the pupfishes Cyprinodon atrorus and Cyprinodon bifasciatus was tested via spatio-temporal analyses of environmental and genetic change over winter, spring and summer for three consecutive years. A critical influence of exogenous selection on hybrid zone regulation was demonstrated by a significant relationship between environmental (salinity and temperature) and genetic (three diagnostic nuDNA loci) variation over space and time (seasons) in the Rio Churince system, Cuatro Ciénegas, Mexico. At sites environmentally more similar to parental habitats, the genetic composition of hybrids was stable and similar to the resident parental species, whereas complex admixtures of parental and hybrid genotypic classes characterized intermediate environments, as did the greatest change in allelic and genotypic frequencies across seasons. Within hybrids across the entire Rio Churince system, seasonal changes in allelic and genotypic frequencies were consistent with results from previous reciprocal transplant experiments, which showed C. bifasciatus to suffer high mortality (75%) when exposed to the habitat of C. atrorus in winter (extreme temperature lows and variability) and summer (abrupt salinity change and extreme temperature highs and variability). Although unconfirmed, the distributional limits of C. atrorus and C. atrorus-like hybrids appear to be governed by similar constraints (predation or competition). The argument favouring evolutionary significance of hybridization in animals is bolstered by the results of this study, which links the importance of exogenous selection in a contemporary hybrid zone between C. atrorus and C. bifasciatus to previous demonstration of the long-term evolutionary significance of environmental variation and introgression on the phenotypic diversification Cuatro Ciénegas Cyprinodon. © 2012 Blackwell Publishing Ltd.

  1. Domain-dependent electronic structure and optical absorption property in hybrid organic-inorganic perovskite.

    Science.gov (United States)

    Meng, Xiang; Zhang, Ruifeng; Fu, Zhongheng; Zhang, Qianfan

    2016-10-05

    Hybrid organic-inorganic perovskites, represented by materials in the CH3NH3PbI3 series, have become one of the most promising materials for solar cells with a high power conversion efficiency and low cost. The ordered Pb-I cage in such hybrid perovskites can induce the polarized cations to form a variety of polarization domains with long-range order, which will lead to the formation of specific atomic conformations or metastable crystalline phases, unique electronic band structures and optical absorption properties. Such domain-dependent characteristics play a critical role in the phase transition and service stability of such solar cells, and also open up the opportunity of tuning their electronic structure. In the present study, we systematically investigate the band structures and optical absorption properties of different electronically ordered domains in CH3NH3PbI3. By comparing different perovskites containing various cations, we have clarified the important influence of cation polarization on domain-dependent properties. Our results provide not only a possible pathway for the manipulation of band structure by applying an external field, but also a novel scheme for improving the performance and stability of hybrid perovskites.

  2. One-chip electronic detection of DNA hybridization using precision impedance-based CMOS array sensor.

    Science.gov (United States)

    Lee, Kang-Ho; Lee, Jeong-Oen; Sohn, Mi-Jin; Lee, Byunghun; Choi, Suk-Hwan; Kim, Sang Kyu; Yoon, Jun-Bo; Cho, Gyu-Hyeong

    2010-12-15

    This paper describes a label-free and fully electronic detection method of DNA hybridization, which is achieved through the use of a 16×8 microarray sensor in conjunction with a new type of impedance spectroscopy constructed with standard complementary metal-oxide-semiconductor (CMOS) technology. The impedance-based method is based on changes in the reactive capacitance and the charge-transfer resistance after hybridization with complementary DNA targets. In previously published label-free techniques, the measured capacitance presented unstable capacitive properties due to the parallel resistance that is not infinite and can cause a leakage by discharging the charge on the capacitor. This paper presents an impedance extraction method that uses excitation by triangular wave voltage, which enables a reliable measurement of both C and R producing a highly sensitive sensor with a stable operation independent of external variables. The system was fabricated in an industrial 0.35-μm 4-metal 2-poly CMOS process, integrating working electrodes and readout electronics into one chip. The integrated readout, which uses a parasitic insensitive integrator, achieves an enlarged detection range and improved noise performance. The maximum average relative variations of C and R are 31.5% and 68.6%, respectively, after hybridization with a 1 μM target DNA. The proposed sensor allows quantitative evaluation of the molecule densities on the chip with distinguishable variation in the impedance. This fully electronic microsystem has great potential for use with bioanalytical tools and point-of-care diagnosis.

  3. Evidence for acceleration of outer zone electrons to relativistic energies by whistler mode chorus

    Directory of Open Access Journals (Sweden)

    N. P. Meredith

    Full Text Available We use plasma wave and electron data from the Combined Release and Radiation Effects Satellite (CRRES to investigate the viability of a local stochastic electron acceleration mechanism to relativistic energies driven by gyroresonant interactions with whistler mode chorus. In particular, we examine the temporal evolution of the spectral response of the electrons and the waves during the 9 October 1990 geomagnetic storm. The observed hardening of the electron energy spectra over about 3 days in the recovery phase is coincident with prolonged substorm activity, as monitored by the AE index and enhanced levels of whistler mode chorus waves. The observed spectral hardening is observed to take place over a range of energies appropriate to the resonant energies associated with Doppler-shifted cyclotron resonance, as supported by the construction of realistic resonance curves and resonant diffusion surfaces. Furthermore, we show that the observed spectral hardening is not consistent with energy-independent radial diffusion models. These results provide strong circumstantial evidence for a local stochastic acceleration mechanism, involving the energisation of a seed population of electrons with energies of the order of a few hundred keV to relativistic energies, driven by wave-particle interactions involving whistler mode chorus. The results suggest that this mechanism contributes to the reformation of the relativistic outer zone population during geomagnetic storms, and is most effective when the recovery phase is characterised by prolonged substorm activity. An additional significant result of this paper is that we demonstrate that the lower energy part of the storm-time electron distribution is in steady-state balance, in accordance with the Kennel and Petschek (1966 theory of limited stably-trapped particle fluxes.

    Key words. Magnetospheric physics (storms and substorms, energetic particles, trapped – Space plasma physics (wave

  4. Localized heating of electrons in ionization zones: Going beyond the Penning-Thornton paradigm in magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Anders, Andre

    2014-12-07

    The fundamental question of how energy is supplied to a magnetron discharge is commonly answered by the Penning-Thornton paradigm invoking secondary electrons. Huo et al. (Plasma Sources Sci. Technol. 22, 045005, (2013)) used a global discharge model to show that electron heating in the electric field of the magnetic presheath is dominant. In this contribution, this concept is applied locally taking into account the electric potential structure of ionization zones. Images of ionization zones can and should be interpreted as diagrams of the localization of electric potential and related electron energy, where certain collisions promote or dampen their formation.

  5. Photoemission study of ferrocenes: insights into the electronic structure of Si-based hybrid materials

    Energy Technology Data Exchange (ETDEWEB)

    Boccia, A; Marrani, A G; Stranges, S; Zanoni, R [Dipartimento di Chimica, Universita degli Studi di Roma ' La Sapienza' , piazzale Aldo Moro 5, I-00185 Rome (Italy); Alagia, M [ISMN-CNR, Sezione Romal, Piazzale Aldo Moro 5, I-00185 Roma, Italy and Laboratorio Nazionale TASC-CNR SS-14, Km 163.5, Basovizza, I-34012 Trieste (Italy); Iozzi, M F; Cossi, M [Dipartimento di Scienze dell' Ambiente e della Vita, Universita del Piemonte Orientale, via V. Bellini 25/G, I-15100 Alessandria (Italy)], E-mail: Andrea.Marrani@uniromal.it

    2008-03-15

    We present here the results of synchrotron radiation-excited UV-photoemission investigation and DFT calculations on vinylferrocene (VFC), a redox molecule suitable for applications in molecular electronics. A detailed assignment is discussed of the valence photoelectron spectra (UPS), which provides new data on the electronic structure and offers a partial re-interpretation of previous assignments on VFC based on theoretical and experimental evidences. Furthermore, the present results can allow for a meaningful comparison of photoemission results from the corresponding hybrid obtained by covalently attaching VFC to Si oriented surfaces.

  6. Quantum teleportation and entanglement swapping of electron spins in superconducting hybrid structures

    Energy Technology Data Exchange (ETDEWEB)

    Bubanja, Vladimir, E-mail: vladimir.bubanja@callaghaninnovation.govt.nz

    2015-06-15

    We present schemes for quantum teleportation and entanglement swapping of electronic spin states in hybrid superconductor–normal-metal systems. The proposed schemes employ subgap transport whereby the lowest order processes involve Cooper pair-electron and double Cooper-pair cotunneling in quantum teleportation and entanglement swapping protocols, respectively. The competition between elastic cotunneling and Cooper-pair splitting results in the success probability of 25% in both cases. Described implementations of these protocols are within reach of present-day experimental techniques.

  7. A hybrid density functional study on the electron and hole trap states in anatase titanium dioxide.

    Science.gov (United States)

    Yamamoto, Takenori; Ohno, Takahisa

    2012-01-14

    We present a theoretical study on electron and hole trap states in the bulk and (001) surface of anatase titanium dioxide using screened hybrid density functional calculations. In both the bulk and surface, calculations suggest that the neutral and ionized oxygen vacancies are possible electron traps. The doubly ionized oxygen vacancy is the most stable in the bulk, and is a candidate for a shallow donor in colorless anatase crystals. The hole trap states are localized at oxygen anions in both the bulk and surface. The self-trapped electron centered at a titanium cation cannot be produced in the bulk, but can be formed at the surface. The electron trap level at the surface oxygen vacancy is consistent with observations by photoelectron spectroscopy. The optical absorptions and luminescence in UV-irradiated anatase nanoparticles are found to come from the surface self-trapped hole and the surface oxygen vacancy.

  8. The nature of excess electrons in anatase and rutile from hybrid DFT and RPA.

    Science.gov (United States)

    Spreafico, Clelia; VandeVondele, Joost

    2014-12-21

    The behavior of excess electrons in undoped and defect free bulk anatase and rutile TiO2 has been investigated by state-of-the-art electronic structure methods including hybrid density functional theory (DFT) and the random phase approximation (RPA). Consistent with experiment, charge trapping and polaron formation is observed in both anatase and rutile. The difference in the anisotropic shape of the polarons is characterized, confirming for anatase the large polaron picture. For anatase, where polaron formation energies are small, charge trapping is observed also with standard hybrid functionals, provided the simulation cell is sufficiently large (864 atoms) to accommodate the lattice relaxation. Even though hybrid orbitals are required as a starting point for RPA in this system, the obtained polaron formation energies are relatively insensitive to the amount of Hartree-Fock exchange employed. The difference in trapping energy between rutile and anatase can be obtained accurately with both hybrid functionals and RPA. Computed activation energies for polaron hopping and delocalization clearly show that anatase and rutile might have different charge transport mechanisms. In rutile, only hopping is likely, whereas in anatase hopping and delocalization are competing. Delocalization will result in conduction-band-like and thus enhanced transport. Anisotropic conduction, in agreement with experimental data, is observed, and results from the tendency to delocalize in the [001] direction in rutile and the (001) plane in anatase. For future work, our calculations serve as a benchmark and suggest RPA on top on hybrid orbitals (PBE0 with 30% Hartree-Fock exchange), as a suitable method to study the rich chemistry and physics of TiO2.

  9. Ecological differentiation, lack of hybrids involving diploids, and asymmetric gene flow between polyploids in narrow contact zones of Senecio carniolicus (syn. Jacobaea carniolica, Asteraceae).

    Science.gov (United States)

    Hülber, Karl; Sonnleitner, Michaela; Suda, Jan; Krejčíková, Jana; Schönswetter, Peter; Schneeweiss, Gerald M; Winkler, Manuela

    2015-03-01

    Areas of immediate contact of different cytotypes offer a unique opportunity to study evolutionary dynamics within heteroploid species and to assess isolation mechanisms governing coexistence of cytotypes of different ploidy. The degree of reproductive isolation of cytotypes, that is, the frequency of heteroploid crosses and subsequent formation of viable and (partly) fertile hybrids, plays a crucial role for the long-term integrity of lineages in contact zones. Here, we assessed fine-scale distribution, spatial clustering, and ecological niches as well as patterns of gene flow in parental and hybrid cytotypes in zones of immediate contact of di-, tetra-, and hexaploid Senecio carniolicus (Asteraceae) in the Eastern Alps. Cytotypes were spatially separated also at the investigated microscale; the strongest spatial separation was observed for the fully interfertile tetra- and hexaploids. The three main cytotypes showed highly significant niche differences, which were, however, weaker than across their entire distribution ranges in the Eastern Alps. Individuals with intermediate ploidy levels were found neither in the diploid/tetraploid nor in the diploid/hexaploid contact zones indicating strong reproductive barriers. In contrast, pentaploid individuals were frequent in the tetraploid/hexaploid contact zone, albeit limited to a narrow strip in the immediate contact zone of their parental cytotypes. AFLP fingerprinting data revealed introgressive gene flow mediated by pentaploid hybrids from tetra- to hexaploid individuals, but not vice versa. The ecological niche of pentaploids differed significantly from that of tetraploids but not from hexaploids.

  10. Quantum-chemical studies of quasi-one-dimensional electron systems. Part 2. Cumulenes and origin of the forbidden zone

    Directory of Open Access Journals (Sweden)

    Yuriy Kruglyak

    2015-06-01

    Full Text Available This review is devoted to the basic problem in quantum theory of quasi-one-dimensional electron systems like polyenes (Part 1 and cumulenes (Part 2 – physical origin of the forbidden zone in these and analogous 1D electron systems due to two possible effects – Peierls instability (bond alternation and Mott instability (electron correlation. Both possible contradiction and coexistence of the Mott and Peierls instabilities are summerized on the basis of the Kiev quantum chemistry team research projects.

  11. The analysis of single-electron orbits in a free electron laser based upon a rectangular hybrid wiggler

    Science.gov (United States)

    Kordbacheh, A.; Ghahremaninezhad, Roghayeh; Maraghechi, B.

    2012-09-01

    A three-dimensional analysis of a novel free-electron laser (FEL) based upon a rectangular hybrid wiggler (RHW) is presented. This RHW is designed in a configuration composed of rectangular rings with alternating ferrite and dielectric spacers immersed in a solenoidal magnetic field. An analytic model of RHW is introduced by solution of Laplace's equation for the magnetostatic fields under the appropriate boundary conditions. The single-electron orbits in combined RHW and axial guide magnetic fields are studied when only the first and the third spatial harmonic components of the RHW field are taken into account and the higher order terms are ignored. The results indicate that the third spatial harmonic leads to group III orbits with a strong negative mass regime particularly in large solenoidal magnetic fields. RHW is found to be a promising candidate with favorable characteristics to be used in microwave FEL.

  12. Direct switching control of DC-DC power electronic converters using hybrid system theory

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, J.; Lin, F. [Wayne State Univ., Detroit, MI (United States). Dept. of Electrical and Computer Engineering; Wang, C. [Wayne State Univ., Detroit, MI (United States). Dept. of Electrical and Computer Engineering; Wayne State Univ., Detroit, MI (United States). Div. of Engineering Technology

    2010-07-01

    A direct switching control (DSC) scheme for power electronics converters was described. The system was designed for use in both traditional and renewable energy applications as well as in electric drive vehicles. The proposed control scheme was based on a detailed hybrid system converter model that used model predictive control (MPC), piecewise affine (PWA) approximations and constrained optimal control methods. A DC-DC converter was modelled as a hybrid machine. Switching among different modes of the DC-DC converter were modelled as discrete events controlled by the hybrid controller. The modelling scheme was applied to a Buck converter. The DSC was used to control the switch of the power converter based on a hybrid machine model. Results of the study showed that the method can be used to regulate output voltage and inductor currents. The method also provides fast transient responses and effectively regulates both currents and voltage. The controller can be used to provide immediate responses to dynamic disturbances and output voltage fluctuations. 23 refs., 7 figs.

  13. Hybrid density functional study of the structural, bonding, and electronic properties of bismuth vanadate

    Science.gov (United States)

    Kweon, Kyoung E.; Hwang, Gyeong S.

    2012-10-01

    The structure and property prediction of metal oxides can significantly be improved by incorporating exact Hartree-Fock (HF) exchange into density functional theory (DFT), which is the so-called hybrid DFT. We explored the impact of HF exchange inclusion on the predicted structural, bonding, and electronic properties of bismuth vanadate (BiVO4), with particular attention to the difference between its monoclinic and tetragonal scheelite phases. The applied exchange-correlation (xc) functionals include the gradient corrected Perdew-Burke-Ernzerhof (PBE) and the PBE-HF hybrid functionals with HF exchange amounts of 10%, 25%, and 50%. We find that the PBE-HF25% yields a monoclinic structure in very close agreement with the experimentally determined structure, while the PBE-HF50% tends to overestimate the monoclinic distortion and the PBE/PBE-HF10% can hardly identify a distinct monoclinic configuration at ambient conditions. Electronic structure analysis reveals that the increasing monoclinic distortion with the amount of HF exchange is related to the enhancement of hybridization between Bi 6s-O 2p antibonding states and unoccupied Bi 6p states. The bonding mechanisms and band structures of the monoclinic and tetragonal phases of BiVO4 were also investigated, and we discuss how the predictions are sensitive to the xc functional choice.

  14. In situ bioremediation of nitrate and perchlorate in vadose zone soil for groundwater protection using gaseous electron donor injection technology.

    Science.gov (United States)

    Evans, Patrick J; Trute, Mary M

    2006-12-01

    When present in the vadose zone, potentially toxic nitrate and perchlorate anions can be persistent sources of groundwater contamination. Gaseous electron donor injection technology (GEDIT), an anaerobic variation of petroleum hydrocarbon bioventing, involves injecting electron donor gases, such as hydrogen or ethyl acetate, into the vadose zone, to stimulate biodegradation of nitrate and perchlorate. Laboratory microcosm studies demonstrated that hydrogen and ethanol promoted nitrate and perchlorate reduction in vadose zone soil and that moisture content was an important factor. Column studies demonstrated that transport of particular electron donors varied significantly; ethyl acetate and butyraldehyde were transported more rapidly than butyl acetate and ethanol. Nitrate removal in the column studies, up to 100%, was best promoted by ethyl acetate. Up to 39% perchlorate removal was achieved with ethanol and was limited by insufficient incubation time. The results demonstrate that GEDIT is a promising remediation technology warranting further validation.

  15. Electronic structures of one-dimensional metal-molecule hybrid chains studied using scanning tunneling microscopy and density functional theory.

    Science.gov (United States)

    Chung, Kyung-Hoon; Koo, Bon-Gil; Kim, Howon; Yoon, Jong Keon; Kim, Ji-Hoon; Kwon, Young-Kyun; Kahng, Se-Jong

    2012-05-28

    The electronic structures of self-assembled hybrid chains comprising Ag atoms and organic molecules were studied using scanning tunneling microscopy (STM) and spectroscopy (STS) in parallel with density functional theory (DFT). Hybrid chains were prepared by catalytic breaking of Br-C bonds in 4,4″-dibromo-p-terphenyl molecules, followed by spontaneous formation of Ag-C bonds on Ag(111). An atomic model was proposed for the observed hybrid chain structures. Four electronic states were resolved using STS measurements, and strong energy dependence was observed in STM images. These results were explained using first-principles calculations based on DFT.

  16. Femtosecond spectroscopic studies of photoinduced electron transfer in MDMO-PPV:ZnO hybrid bulk heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Cecchetto, E.; De Cola, L. [Institute of Physics, University of Muenster, Mendelstrasse 7, 48149 Muenster (Germany); Slooff, H. [ECN Solar Energy, P.O. Box 1, 1755 ZG Petten (Netherlands); Zhang, H. [Van ' t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 129, 1018 WS Amsterdam (Netherlands)

    2007-01-15

    The photophysics of charge carriers (polaron) in MDMO-PPV:ZnO hybrid bulk heterojunction is studied at 80 K by femtosecond transient absorption spectroscopy. A short-lived positive polaron is observed in the blend phase in MDMO-PPV:ZnO blend films with a weight ratio of 1:1 and 1:2. Further increase of ZnO weight ratio results in a significant quenching of the polaron absorption. The results are discussed in the concept that both pristine polymer and MDMO-PPV:ZnO blend phases coexist in the blend films. It is concluded that a polaron is photogenerated within the excitation laser pulse (<100 fs) and electron transfer efficiency is highest in blend films 1:1 and 1:2. Lack of the interfacial area and faster back electron transfer process are discussed to be responsible for the quenching of the electron transfer efficiency in blend film 1:3.

  17. A linear dispersion relation for the hybrid kinetic-ion/fluid-electron model of plasma physics

    CERN Document Server

    Told, Daniel; Astfalk, Patrick; Jenko, Frank

    2016-01-01

    A dispersion relation for a commonly used hybrid model of plasma physics is developed, which combines fully kinetic ions and a massless-electron fluid description. Although this model and variations of it have been used to describe plasma phenomena for about 40 years, to date there exists no general dispersion relation to describe the linear wave physics contained in the model. Previous efforts along these lines are extended here to retain arbitrary wave propagation angles, temperature anisotropy effects, as well as additional terms in the generalized Ohm's law which determines the electric field. A numerical solver for the dispersion relation is developed, and linear wave physics is benchmarked against solutions of a full Vlasov-Maxwell dispersion relation solver. This work opens the door to a more accurate interpretation of existing and future wave and turbulence simulations using this type of hybrid model.

  18. Adaptive traits are maintained on steep selective gradients despite gene flow and hybridization in the intertidal zone.

    Directory of Open Access Journals (Sweden)

    Gerardo I Zardi

    Full Text Available Gene flow among hybridizing species with incomplete reproductive barriers blurs species boundaries, while selection under heterogeneous local ecological conditions or along strong gradients may counteract this tendency. Congeneric, externally-fertilizing fucoid brown algae occur as distinct morphotypes along intertidal exposure gradients despite gene flow. Combining analyses of genetic and phenotypic traits, we investigate the potential for physiological resilience to emersion stressors to act as an isolating mechanism in the face of gene flow. Along vertical exposure gradients in the intertidal zone of Northern Portugal and Northwest France, the mid-low shore species Fucus vesiculosus, the upper shore species Fucus spiralis, and an intermediate distinctive morphotype of F. spiralis var. platycarpus were morphologically characterized. Two diagnostic microsatellite loci recovered 3 genetic clusters consistent with prior morphological assignment. Phylogenetic analysis based on single nucleotide polymorphisms in 14 protein coding regions unambiguously resolved 3 clades; sympatric F. vesiculosus, F. spiralis, and the allopatric (in southern Iberia population of F. spiralis var. platycarpus. In contrast, the sympatric F. spiralis var. platycarpus (from Northern Portugal was distributed across the 3 clades, strongly suggesting hybridization/introgression with both other entities. Common garden experiments showed that physiological resilience following exposure to desiccation/heat stress differed significantly between the 3 sympatric genetic taxa; consistent with their respective vertical distribution on steep environmental clines in exposure time. Phylogenetic analyses indicate that F. spiralis var. platycarpus is a distinct entity in allopatry, but that extensive gene flow occurs with both higher and lower shore species in sympatry. Experimental results suggest that strong selection on physiological traits across steep intertidal exposure gradients

  19. Adaptive Traits Are Maintained on Steep Selective Gradients despite Gene Flow and Hybridization in the Intertidal Zone

    Science.gov (United States)

    Canovas, Fernando; Ferreira Costa, Joana; Serrão, Ester A.; Pearson, Gareth A.

    2011-01-01

    Gene flow among hybridizing species with incomplete reproductive barriers blurs species boundaries, while selection under heterogeneous local ecological conditions or along strong gradients may counteract this tendency. Congeneric, externally-fertilizing fucoid brown algae occur as distinct morphotypes along intertidal exposure gradients despite gene flow. Combining analyses of genetic and phenotypic traits, we investigate the potential for physiological resilience to emersion stressors to act as an isolating mechanism in the face of gene flow. Along vertical exposure gradients in the intertidal zone of Northern Portugal and Northwest France, the mid-low shore species Fucus vesiculosus, the upper shore species Fucus spiralis, and an intermediate distinctive morphotype of F. spiralis var. platycarpus were morphologically characterized. Two diagnostic microsatellite loci recovered 3 genetic clusters consistent with prior morphological assignment. Phylogenetic analysis based on single nucleotide polymorphisms in 14 protein coding regions unambiguously resolved 3 clades; sympatric F. vesiculosus, F. spiralis, and the allopatric (in southern Iberia) population of F. spiralis var. platycarpus. In contrast, the sympatric F. spiralis var. platycarpus (from Northern Portugal) was distributed across the 3 clades, strongly suggesting hybridization/introgression with both other entities. Common garden experiments showed that physiological resilience following exposure to desiccation/heat stress differed significantly between the 3 sympatric genetic taxa; consistent with their respective vertical distribution on steep environmental clines in exposure time. Phylogenetic analyses indicate that F. spiralis var. platycarpus is a distinct entity in allopatry, but that extensive gene flow occurs with both higher and lower shore species in sympatry. Experimental results suggest that strong selection on physiological traits across steep intertidal exposure gradients acts to maintain

  20. Adaptive traits are maintained on steep selective gradients despite gene flow and hybridization in the intertidal zone.

    Science.gov (United States)

    Zardi, Gerardo I; Nicastro, Katy R; Canovas, Fernando; Costa, Joana Ferreira; Serrão, Ester A; Pearson, Gareth A

    2011-01-01

    Gene flow among hybridizing species with incomplete reproductive barriers blurs species boundaries, while selection under heterogeneous local ecological conditions or along strong gradients may counteract this tendency. Congeneric, externally-fertilizing fucoid brown algae occur as distinct morphotypes along intertidal exposure gradients despite gene flow. Combining analyses of genetic and phenotypic traits, we investigate the potential for physiological resilience to emersion stressors to act as an isolating mechanism in the face of gene flow. Along vertical exposure gradients in the intertidal zone of Northern Portugal and Northwest France, the mid-low shore species Fucus vesiculosus, the upper shore species Fucus spiralis, and an intermediate distinctive morphotype of F. spiralis var. platycarpus were morphologically characterized. Two diagnostic microsatellite loci recovered 3 genetic clusters consistent with prior morphological assignment. Phylogenetic analysis based on single nucleotide polymorphisms in 14 protein coding regions unambiguously resolved 3 clades; sympatric F. vesiculosus, F. spiralis, and the allopatric (in southern Iberia) population of F. spiralis var. platycarpus. In contrast, the sympatric F. spiralis var. platycarpus (from Northern Portugal) was distributed across the 3 clades, strongly suggesting hybridization/introgression with both other entities. Common garden experiments showed that physiological resilience following exposure to desiccation/heat stress differed significantly between the 3 sympatric genetic taxa; consistent with their respective vertical distribution on steep environmental clines in exposure time. Phylogenetic analyses indicate that F. spiralis var. platycarpus is a distinct entity in allopatry, but that extensive gene flow occurs with both higher and lower shore species in sympatry. Experimental results suggest that strong selection on physiological traits across steep intertidal exposure gradients acts to maintain

  1. Hybrid phospholipid bilayer coatings for separations of cationic proteins in capillary zone electrophoresis.

    Science.gov (United States)

    Gallagher, Elyssia S; Adem, Seid M; Bright, Leonard K; Calderon, Isen A C; Mansfield, Elisabeth; Aspinwall, Craig A

    2014-04-01

    Protein separations in CZE suffer from nonspecific adsorption of analytes to the capillary surface. Semipermanent phospholipid bilayers have been used to minimize adsorption, but must be regenerated regularly to ensure reproducibility. We investigated the formation, characterization, and use of hybrid phospholipid bilayers (HPBs) as more stable biosurfactant capillary coatings for CZE protein separations. HPBs are formed by covalently modifying a support with a hydrophobic monolayer onto which a self-assembled lipid monolayer is deposited. Monolayers prepared in capillaries using 3-cyanopropyldimethylchlorosilane (CPDCS) or n-octyldimethylchlorosilane (ODCS) yielded hydrophobic surfaces with lowered surface free energies of 6.0 ± 0.3 or 0.2 ± 0.1 mJ m(-2) , respectively, compared to 17 ± 1 mJ m(-2) for bare silica capillaries. HPBs were formed by subsequently fusing vesicles comprised of 1,2-dilauroyl-sn-glycero-3-phosphocholine or 1,2-dioleoyl-sn-glycero-3-phosphocholine to CPDCS- or ODCS-modified capillaries. The resultant HPB coatings shielded the capillary surface and yielded reduced electroosmotic mobility (1.3-1.9 × 10(-4) cm(2) V(-1) s(-1) ) compared to CPDCS- and ODCS-modified or bare capillaries (3.6 ± 0.2 × 10(-4) cm(2) V(-1) s(-1) , 4.8 ± 0.4 × 10(-4) cm(2) V(-1) s(-1) , and 6.0 ± 0.2 × 10(-4) cm(2) V(-1) s(-1) , respectively), with increased stability compared to phospholipid bilayer coatings. HPB-coated capillaries yielded reproducible protein migration times (RSD ≤ 3.6%, n ≥ 6) with separation efficiencies as high as 200 000 plates/m.

  2. Baboons, water, and the ecology of oxygen stable isotopes in an arid hybrid zone.

    Science.gov (United States)

    Moritz, Gillian L; Fourie, Nicolaas; Yeakel, Justin D; Phillips-Conroy, Jane E; Jolly, Clifford J; Koch, Paul L; Dominy, Nathaniel J

    2012-01-01

    Baboons regularly drink surface waters derived from atmospheric precipitation, or meteoric water. As a result, the oxygen isotope (δ(18)O) composition of their tissues is expected to reflect that of local meteoric waters. Animal proxies of the oxygen isotope composition of meteoric water have practical applications as paleoenvironmental recorders because they can be used to infer aridity and temperature in historic and fossil systems. To explore this premise, we measured the δ(18)O values of hair from two baboon species, Papio anubis and Papio hamadryas, inhabiting Awash National Park, Ethiopia. The hybridizing taxa differ in their ranging behavior and physiological response to heat. Papio hamadryas ranges more widely in the arid thornbush and is inferred to ingest a greater proportion of leaf water that is enriched in (18)O as a result of evaporative fractionation. It is also better able to conserve body water, which reduces its dependence on meteoric waters depleted in (18)O. Taken together, these factors would predict relatively higher δ(18)O values in the hair (δ(18)O(hair)) of P. hamadryas. We found that the δ(18)O(hair) values of P. hamadryas were higher than those of P. anubis, yet the magnitude of the difference was marginal. We attribute this result to a common source of drinking water, the Awash River, and the longer drinking bouts of P. hamadryas. Our findings suggest that differences in δ(18)O values among populations of Papio (modern or ancient) reflect different sources of drinking water (which might have ecological significance) and, further, that Papio has practical value as a paleoenvironmental recorder.

  3. Hybrid two-dimensional electronic systems and other applications of sp-2 bonded light elements

    Science.gov (United States)

    Kessler, Brian Maxwell

    The field-effect is a cornerstone of modern technology lying at the heart of transistors in consumer electronics. Experimentally, it allows one to continuously vary the carrier concentration in a material while studying its properties. The recent isolation of graphene, the first truly two-dimensional crystal, allows application of the field effect to a much wider range of physical situations. In the first part of the thesis, we investigate hybrid materials formed by coupling metals to the two-dimensional electron gas (2DEG) in graphene. We couple superconducting materials to the graphene sheet by cluster deposition. This material displays a superconducting phase whose properties are tuned by the carrier density via the field effect. The transition temperature is well-described by Berezinskii-Kosterlitz-Thouless vortex unbinding. The ground state properties show interesting effects due to the distribution of cluster spacings. Observations related to other hybrid electronic systems including ferromagnets and normal metals are presented. The second part of this thesis involves energy applications of light element materials. The mechanisms affecting coating of carbon nanotubes using atomic layer deposition is developed and applied to photovoltaic systems. The gas adsorption properties of activated boron nitride are investigated and the relative influence of surface area and hydrogen binding affinity is elaborated. The third part of this thesis explores electromechanical properties of suspended graphene membranes. We investigate buckling and strain in exfoliated graphene membranes as well as their deformation under an applied gate potential.

  4. Fluorescent Nanodiamond-Gold Hybrid Particles for Multimodal Optical and Electron Microscopy Cellular Imaging.

    Science.gov (United States)

    Liu, Weina; Naydenov, Boris; Chakrabortty, Sabyasachi; Wuensch, Bettina; Hübner, Kristina; Ritz, Sandra; Cölfen, Helmut; Barth, Holger; Koynov, Kaloian; Qi, Haoyuan; Leiter, Robert; Reuter, Rolf; Wrachtrup, Jörg; Boldt, Felix; Scheuer, Jonas; Kaiser, Ute; Sison, Miguel; Lasser, Theo; Tinnefeld, Philip; Jelezko, Fedor; Walther, Paul; Wu, Yuzhou; Weil, Tanja

    2016-10-12

    There is a continuous demand for imaging probes offering excellent performance in various microscopy techniques for comprehensive investigations of cellular processes by more than one technique. Fluorescent nanodiamond-gold nanoparticles (FND-Au) constitute a new class of "all-in-one" hybrid particles providing unique features for multimodal cellular imaging including optical imaging, electron microscopy, and, and potentially even quantum sensing. Confocal and optical coherence microscopy of the FND-Au allow fast investigations inside living cells via emission, scattering, and photothermal imaging techniques because the FND emission is not quenched by AuNPs. In electron microscopy, transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) analysis of FND-Au reveals greatly enhanced contrast due to the gold particles as well as an extraordinary flickering behavior in three-dimensional cellular environments originating from the nanodiamonds. The unique multimodal imaging characteristics of FND-Au enable detailed studies inside cells ranging from statistical distributions at the entire cellular level (micrometers) down to the tracking of individual particles in subcellular organelles (nanometers). Herein, the processes of endosomal membrane uptake and release of FNDs were elucidated for the first time by the imaging of individual FND-Au hybrid nanoparticles with single-particle resolution. Their convenient preparation, the availability of various surface groups, their flexible detection modalities, and their single-particle contrast in combination with the capability for endosomal penetration and low cytotoxicity make FND-Au unique candidates for multimodal optical-electronic imaging applications with great potential for emerging techniques, such as quantum sensing inside living cells.

  5. A hybrid zone between Bathymodiolus mussel lineages from eastern Pacific hydrothermal vents

    Directory of Open Access Journals (Sweden)

    Johnson Shannon B

    2013-01-01

    Full Text Available Abstract Background The inhabitants of deep-sea hydrothermal vents occupy ephemeral island-like habitats distributed sporadically along tectonic spreading-centers, back-arc basins, and volcanically active seamounts. The majority of vent taxa undergo a pelagic larval phase, and thus varying degrees of geographical subdivision, ranging from no impedance of dispersal to complete isolation, often exist among taxa that span common geomorphological boundaries. Two lineages of Bathymodiolus mussels segregate on either side of the Easter Microplate, a boundary that separates the East Pacific Rise from spreading centers connected to the Pacific-Antarctic Ridge. Results A recent sample from the northwest flank of the Easter Microplate contained an admixture of northern and southern mitochondrial haplotypes and corresponding alleles at five nuclear gene loci. Genotypic frequencies in this sample did not fit random mating expectation. Significant heterozygote deficiencies at nuclear loci and gametic disequilibria between loci suggested that this transitional region might be a ‘Tension Zone’ maintained by immigration of parental types and possibly hybrid unfitness. An analysis of recombination history in the nuclear genes suggests a prolonged history of parapatric contact between the two mussel lineages. We hereby elevate the southern lineage to species status as Bathymodiolus antarcticus n. sp. and restrict the use of Bathymodiolus thermophilus to the northern lineage. Conclusions Because B. thermophilus s.s. exhibits no evidence for subdivision or isolation-by-distance across its 4000 km range along the EPR axis and Galápagos Rift, partial isolation of B. antarcticus n. sp. requires explanation. The time needed to produce the observed degree of mitochondrial differentiation is consistent with the age of the Easter Microplate (2.5 to 5.3 million years. The complex geomorphology of the Easter Microplate region forces strong cross-axis currents that

  6. A Novel Hybrid Intelligent Indoor Location Method for Mobile Devices by Zones Using Wi-Fi Signals

    Directory of Open Access Journals (Sweden)

    Manuel Castañón–Puga

    2015-12-01

    Full Text Available The increasing use of mobile devices in indoor spaces brings challenges to location methods. This work presents a hybrid intelligent method based on data mining and Type-2 fuzzy logic to locate mobile devices in an indoor space by zones using Wi-Fi signals from selected access points (APs. This approach takes advantage of wireless local area networks (WLANs over other types of architectures and implements the complete method in a mobile application using the developed tools. Besides, the proposed approach is validated by experimental data obtained from case studies and the cross-validation technique. For the purpose of generating the fuzzy rules that conform to the Takagi–Sugeno fuzzy system structure, a semi-supervised data mining technique called subtractive clustering is used. This algorithm finds centers of clusters from the radius map given by the collected signals from APs. Measurements of Wi-Fi signals can be noisy due to several factors mentioned in this work, so this method proposed the use of Type-2 fuzzy logic for modeling and dealing with such uncertain information.

  7. A Novel Hybrid Intelligent Indoor Location Method for Mobile Devices by Zones Using Wi-Fi Signals.

    Science.gov (United States)

    Castañón-Puga, Manuel; Salazar, Abby Stephanie; Aguilar, Leocundo; Gaxiola-Pacheco, Carelia; Licea, Guillermo

    2015-12-02

    The increasing use of mobile devices in indoor spaces brings challenges to location methods. This work presents a hybrid intelligent method based on data mining and Type-2 fuzzy logic to locate mobile devices in an indoor space by zones using Wi-Fi signals from selected access points (APs). This approach takes advantage of wireless local area networks (WLANs) over other types of architectures and implements the complete method in a mobile application using the developed tools. Besides, the proposed approach is validated by experimental data obtained from case studies and the cross-validation technique. For the purpose of generating the fuzzy rules that conform to the Takagi-Sugeno fuzzy system structure, a semi-supervised data mining technique called subtractive clustering is used. This algorithm finds centers of clusters from the radius map given by the collected signals from APs. Measurements of Wi-Fi signals can be noisy due to several factors mentioned in this work, so this method proposed the use of Type-2 fuzzy logic for modeling and dealing with such uncertain information.

  8. Identification of Culex pipiens complex mosquitoes in a hybrid zone of West Nile virus transmission in Fresno County, California.

    Science.gov (United States)

    McAbee, Rory D; Green, Emily N; Holeman, Jodie; Christiansen, Julie; Frye, Niki; Dealey, Katherine; Mulligan, F Steve; Brault, Aaron C; Cornel, Anthony J

    2008-02-01

    Culex pipiens sensu lato mosquitoes were collected from 24 gravid traps (mid-June to mid-October, 2005) in Fresno County, CA. Captured gravid females were allowed to oviposit before sibling species identification by Ace.2 PCR and detection of West Nile virus (WNV) RNA by RT-PCR were performed on the mother and her offspring. Of the 442 Cx. pipiens s.l. female mosquitoes collected, 88 were positive for WNV viral RNA (peaked in August) with no significant differences among complex members or habitat. Vertical transmission was detected in 4 out of 20 families originating from WNV-positive mothers, however, in only a small number of offspring from each family. Out of 101 families that had PCR-based maternal and offspring identifications, the offspring from 15 families produced inexplicable amplicon patterns, suggesting ambiguities in the PCR assay identifications. Male genitalia (DV/D ratio) and Ace.2 PCR identifications revealed numerous discrepancies in our ability to accurately determine the identity of Cx. pipiens complex members in the hybrid zone of Fresno County.

  9. Donor-acceptor graphene-based hybrid materials facilitating photo-induced electron-transfer reactions.

    Science.gov (United States)

    Stergiou, Anastasios; Pagona, Georgia; Tagmatarchis, Nikos

    2014-01-01

    Graphene research and in particular the topic of chemical functionalization of graphene has exploded in the last decade. The main aim is to increase the solubility and thereby enhance the processability of the material, which is otherwise insoluble and inapplicable for technological applications when stacked in the form of graphite. To this end, initially, graphite was oxidized under harsh conditions to yield exfoliated graphene oxide sheets that are soluble in aqueous media and amenable to chemical modifications due to the presence of carboxylic acid groups at the edges of the lattice. However, it was obvious that the high-defect framework of graphene oxide cannot be readily utilized in applications that are governed by charge-transfer processes, for example, in solar cells. Alternatively, exfoliated graphene has been applied toward the realization of some donor-acceptor hybrid materials with photo- and/or electro-active components. The main body of research regarding obtaining donor-acceptor hybrid materials based on graphene to facilitate charge-transfer phenomena, which is reviewed here, concerns the incorporation of porphyrins and phthalocyanines onto graphene sheets. Through illustrative schemes, the preparation and most importantly the photophysical properties of such graphene-based ensembles will be described. Important parameters, such as the generation of the charge-separated state upon photoexcitation of the organic electron donor, the lifetimes of the charge-separation and charge-recombination as well as the incident-photon-to-current efficiency value for some donor-acceptor graphene-based hybrids, will be discussed.

  10. Hybrid Numerical Solvers for Massively Parallel Eigenvalue Computation and Their Benchmark with Electronic Structure Calculations

    CERN Document Server

    Imachi, Hiroto

    2015-01-01

    Optimally hybrid numerical solvers were constructed for massively parallel generalized eigenvalue problem (GEP).The strong scaling benchmark was carried out on the K computer and other supercomputers for electronic structure calculation problems in the matrix sizes of M = 10^4-10^6 with upto 105 cores. The procedure of GEP is decomposed into the two subprocedures of the reducer to the standard eigenvalue problem (SEP) and the solver of SEP. A hybrid solver is constructed, when a routine is chosen for each subprocedure from the three parallel solver libraries of ScaLAPACK, ELPA and EigenExa. The hybrid solvers with the two newer libraries, ELPA and EigenExa, give better benchmark results than the conventional ScaLAPACK library. The detailed analysis on the results implies that the reducer can be a bottleneck in next-generation (exa-scale) supercomputers, which indicates the guidance for future research. The code was developed as a middleware and a mini-application and will appear online.

  11. Highly transparent, low-haze, hybrid cellulose nanopaper as electrodes for flexible electronics.

    Science.gov (United States)

    Xu, Xuezhu; Zhou, Jian; Jiang, Long; Lubineau, Gilles; Ng, Tienkhee; Ooi, Boon S; Liao, Hsien-Yu; Shen, Chao; Chen, Long; Zhu, J Y

    2016-06-16

    Paper is an excellent candidate to replace plastics as a substrate for flexible electronics due to its low cost, renewability and flexibility. Cellulose nanopaper (CNP), a new type of paper made of nanosized cellulose fibers, is a promising substrate material for transparent and flexible electrodes due to its potentially high transparency and high mechanical strength. Although CNP substrates can achieve high transparency, they are still characterized by high diffuse transmittance and small direct transmittance, resulting in high optical haze of the substrates. In this study, we proposed a simple methodology for large-scale production of high-transparency, low-haze CNP comprising both long cellulose nanofibrils (CNFs) and short cellulose nanocrystals (CNCs). By varying the CNC/CNF ratio in the hybrid CNP, we could tailor its total transmittance, direct transmittance and diffuse transmittance. By increasing the CNC content, the optical haze of the hybrid CNP could be decreased and its transparency could be increased. The direct transmittance and optical haze of the CNP were 75.1% and 10.0%, respectively, greatly improved from the values of previously reported CNP (31.1% and 62.0%, respectively). Transparent, flexible electrodes were fabricated by coating the hybrid CNP with silver nanowires (AgNWs). The electrodes showed a low sheet resistance (minimum 1.2 Ω sq(-1)) and a high total transmittance (maximum of 82.5%). The electrodes were used to make a light emitting diode (LED) assembly to demonstrate their potential use in flexible displays.

  12. A hybrid electron donor comprising cyclopentadithiophene and dithiafulvenyl for dye-sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Gleb Sorohhov

    2015-06-01

    Full Text Available Two new photosensitizers featured with a cyanoacrylic acid electron acceptor (A and a hybrid electron donor (D of cyclopentadithiophene and dithiafulvenyl, either directly linked or separated by a phenyl ring, were synthesized and characterized. Both of them undergo two reversible oxidations and strongly absorb in the visible spectral region due to a photo-induced intramolecular charge-transfer (ICT transition. To a great extent, the electronic interaction between the D and A units is affected by the presence of a phenyl spacer. Without a phenyl ring, the D unit appears more difficult to oxidize due to a strong electron-withdrawing effect of the A moiety. In sharp contrast, the insertion of the phenyl ring between the D and A units leads to a broken π-conjugation and therefore, the oxidation potentials remain almost unchanged compared to those of an analogue without the A group, suggesting that the electronic coupling between D and A units is relatively weak. As a consequence, the lowest-energy absorption band shows a slight hypsochromic shift upon the addition of the phenyl spacer, indicative of an increased HOMO–LUMO gap. In turn, the direct linkage of D and A units leads to an effective π-conjugation, thus substantially lowering the HOMO–LUMO gap. Moreover, the application in dye-sensitized solar cells was investigated, showing that the power conversion efficiency increases by the insertion of the phenyl unit.

  13. A hybrid electron donor comprising cyclopentadithiophene and dithiafulvenyl for dye-sensitized solar cells.

    Science.gov (United States)

    Sorohhov, Gleb; Yi, Chenyi; Grätzel, Michael; Decurtins, Silvio; Liu, Shi-Xia

    2015-01-01

    Two new photosensitizers featured with a cyanoacrylic acid electron acceptor (A) and a hybrid electron donor (D) of cyclopentadithiophene and dithiafulvenyl, either directly linked or separated by a phenyl ring, were synthesized and characterized. Both of them undergo two reversible oxidations and strongly absorb in the visible spectral region due to a photo-induced intramolecular charge-transfer (ICT) transition. To a great extent, the electronic interaction between the D and A units is affected by the presence of a phenyl spacer. Without a phenyl ring, the D unit appears more difficult to oxidize due to a strong electron-withdrawing effect of the A moiety. In sharp contrast, the insertion of the phenyl ring between the D and A units leads to a broken π-conjugation and therefore, the oxidation potentials remain almost unchanged compared to those of an analogue without the A group, suggesting that the electronic coupling between D and A units is relatively weak. As a consequence, the lowest-energy absorption band shows a slight hypsochromic shift upon the addition of the phenyl spacer, indicative of an increased HOMO-LUMO gap. In turn, the direct linkage of D and A units leads to an effective π-conjugation, thus substantially lowering the HOMO-LUMO gap. Moreover, the application in dye-sensitized solar cells was investigated, showing that the power conversion efficiency increases by the insertion of the phenyl unit.

  14. Tunable Radiation Response in Hybrid Organic-Inorganic Gate Dielectrics for Low-Voltage Graphene Electronics.

    Science.gov (United States)

    Arnold, Heather N; Cress, Cory D; McMorrow, Julian J; Schmucker, Scott W; Sangwan, Vinod K; Jaber-Ansari, Laila; Kumar, Rajan; Puntambekar, Kanan P; Luck, Kyle A; Marks, Tobin J; Hersam, Mark C

    2016-03-01

    Solution-processed semiconductor and dielectric materials are attractive for future lightweight, low-voltage, flexible electronics, but their response to ionizing radiation environments is not well understood. Here, we investigate the radiation response of graphene field-effect transistors employing multilayer, solution-processed zirconia self-assembled nanodielectrics (Zr-SANDs) with ZrOx as a control. Total ionizing dose (TID) testing is carried out in situ using a vacuum ultraviolet source to a total radiant exposure (RE) of 23.1 μJ/cm(2). The data reveal competing charge density accumulation within and between the individual dielectric layers. Additional measurements of a modified Zr-SAND show that varying individual layer thicknesses within the gate dielectric tuned the TID response. This study thus establishes that the radiation response of graphene electronics can be tailored to achieve a desired radiation sensitivity by incorporating hybrid organic-inorganic gate dielectrics.

  15. Role of Microstructure in the Electron-Hole Interaction of Hybrid Lead-Halide Perovskites

    Science.gov (United States)

    Frost, Jarvist M.; Barker, Alex J.; De Bastiani, Michele; Gandini, Marina; Marras, Sergio; Lanzani, Guglielmo; Walsh, Aron; Petrozza, Annamaria

    2015-01-01

    Solar cells based on hybrid inorganic-organic halide perovskites have demonstrated high power conversion efficiencies in a range of architectures. The existence and stability of bound electron-hole pairs in these materials, and their role in the exceptional performance of optoelectronic devices, remains a controversial issue. Here we demonstrate, through a combination of optical spectroscopy and multiscale modeling as a function of the degree of polycrystallinity and temperature, that the electron-hole interaction is sensitive to the microstructure of the material. The long-range order is disrupted by polycrystalline disorder and the variations in electrostatic potential found for smaller crystals suppress exciton formation, while larger crystals of the same composition demonstrate an unambiguous excitonic state. We conclude that fabrication procedures and morphology strongly influence perovskite behaviour, with both free carrier and excitonic regimes possible, with strong implications for optoelectronic devices. PMID:26442125

  16. Hybrid bio-organic interfaces with matchable nanoscale topography for durable high extracellular electron transfer activity.

    Science.gov (United States)

    Ding, Chunmei; Liu, Huan; Lv, Meiling; Zhao, Tianyi; Zhu, Ying; Jiang, Lei

    2014-07-21

    Here, we developed a novel hybrid bio-organic interface with matchable nano-scale topography between a polypyrrole nanowire array (PPy-NA) and the bacterium Shewanella, which enabled a remarkably increased extracellular electron transfer (EET) current from genus Shewanella over a rather long period. PPy-NA thus exhibited outstanding performance in mediating bacterial EET, which was superior to normal electrodes such as carbon plates, Au and tin-doped In₂O₃. It was proposed that the combined effect of the inherent electrochemical nature of PPy and the porous structured bacterial network that was generated on the PPy-NA enabled long-term stability, while the high efficiency was attributed to the enhanced electron transfer rate between PPy-NA and microbes caused by the enhanced local topological interactions.

  17. Role of Microstructure in the Electron-Hole Interaction of Hybrid Lead-Halide Perovskites.

    Science.gov (United States)

    Grancini, Giulia; Srimath Kandada, Ajay Ram; Frost, Jarvist M; Barker, Alex J; De Bastiani, Michele; Gandini, Marina; Marras, Sergio; Lanzani, Guglielmo; Walsh, Aron; Petrozza, Annamaria

    2015-10-01

    Solar cells based on hybrid inorganic-organic halide perovskites have demonstrated high power conversion efficiencies in a range of architectures. The existence and stability of bound electron-hole pairs in these materials, and their role in the exceptional performance of optoelectronic devices, remains a controversial issue. Here we demonstrate, through a combination of optical spectroscopy and multiscale modeling as a function of the degree of polycrystallinity and temperature, that the electron-hole interaction is sensitive to the microstructure of the material. The long-range order is disrupted by polycrystalline disorder and the variations in electrostatic potential found for smaller crystals suppress exciton formation, while larger crystals of the same composition demonstrate an unambiguous excitonic state. We conclude that fabrication procedures and morphology strongly influence perovskite behaviour, with both free carrier and excitonic regimes possible, with strong implications for optoelectronic devices.

  18. Detection of secondary electrons with pixelated hybrid semiconductor detectors; Sekundaerelektronennachweis mit pixelierten hybriden Halbleiterdetektoren

    Energy Technology Data Exchange (ETDEWEB)

    Gebert, Ulrike Sonja

    2011-09-14

    Within the scope of this thesis, secondary electrons were detected with a pixelated semiconductor detector named Timepix. The Timepix detector consists of electronics and a sensor made from a semiconductor material. The connection of sensor and electronics is done for each pixel individually using bump bonds. Electrons with energies above 3 keV can be detected with the sensor. One electron produces a certain amount of electron-hole pairs according to its energy. The charge then drifts along an electric field to the pixel electronics, where it induces an electric signal. Even without a sensor it is possible to detect an electric signal from approximately 1000 electrons directly in the pixel electronics. Two different detector systems to detect secondary electrons using the Timepix detector were investigated during this thesis. First of all, a hybrid photon detector (HPD) was used to detect single photoelectrons. The HPD consists of a vacuum vessel with an entrance window and a cesium iodine photocathode at the inner surface of the window. Photoelectrons are released from the photocathode by incident light and are accelerated in an electric field towards the Timepix detector, where the point of interaction and the arrival time of the electron is determined. With a proximity focusing setup, a time resolution of 12 ns (with an acceleration voltage of 20 kV between photocathode and Timepix detector) was obtained. The HPD examined in this thesis showed a strong dependence of the dark rate form the acceleration voltage and the pressure in the vacuum vessel. At a pressure of few 10{sup -5} mbar and an acceleration voltage of 20 kV, the dark rate was about 800 Hz per mm{sup 2} area of the read out photocathode. One possibility to reduce the dark rate is to identify ion feedback events. With a slightly modified setup it was possible to reduce the dark rate to 0.5 Hz/mm{sup 2}. To achieve this, a new photocathode was mounted in a shorter distance to the detector. The

  19. Experimental investigations on the state of the friction-welded joint zone in steel hybrid components after process-relevant thermo-mechanical loadings

    Science.gov (United States)

    Behrens, B.-A.; Bouguecha, A.; Vucetic, M.; Peshekhodov, I.; Matthias, T.; Kolbasnikov, N.; Sokolov, S.; Ganin, S.

    2016-10-01

    As a part of the newly established Collaborative Research Center 1153 (SFB 1153) "Process chain for the manufacturing of hybrid high-performance components by tailored forming" at the Leibniz Universität Hannover, the Institute of Forming Technology and Machines (IFUM) examines the influence of thermo-mechanical stresses on the reduced Young's modulus as well as the hardness of hybrid (steel-steel compound) joined semi-finished products. Currently the expertise in the production of bulk metal formed parts is limited to mono-materials. For manufacturing parts of hybrid materials and also for the methods of the new process routes, practical experience has to be gained. The subproject C1 within the collaborative research center 1153 with the short title "Failure Prediction" deals with the question, if the hybrid semi-finished products fulfill the thermo-mechanical demands or if they fail at the joining zone (JZ) during forging. For this purpose, stresses similar to those in the process were imposed on hybrid semi-finished products by torsion tests by using the thermo-mechanical test system Gleeble 3800. Afterwards, the specimens were examined metallographically and by nanoindentations with the help of a TriboIndenter TI950. Thus, first knowledge on the behaviour of thermo-mechanical stresses on the reduced Young's modulus and the hardness of hybrid joined semi-finished parts was gained.

  20. Design of hybrid sol gel films for direct x-ray and electron beam nanopatterning

    Science.gov (United States)

    Brusatin, Giovanna; Della Giustina, Gioia; Romanato, Filippo; Guglielmi, Massimo

    2008-04-01

    New epoxy based sol-gel organic inorganic materials, showing lithographic resist-like properties without the addition of any photocatalysts, are presented. To obtain a material sensitive to radiation, specific sol-gel syntheses based on an organically modified alkoxide containing an epoxy ring, 3-glycidoxypropyltrimethoxysilane (GPTMS), have been developed. The synthesis and the patternability of hybrid materials have been obtained controlling the inorganic crosslinking degree and with an almost total absence of organic polymerization. Two examples of directly patternable hybrid films, called GB and GGe, have been synthesized using acidic (GGe) and basic (GB) conditions and obtaining different compositions. After electron beam lithography (EBL) or x-ray synchrotron radiation lithography (XRL) the polymerization of the organic component of the sol-gel film occurs, generating a hardening of the structure after post-exposure baking. The exposed polymerized material becomes insoluble, determining a negative resist-like behaviour of the film: the lithographic process of nanopatterning results from the dissolution of the unexposed areas in proper solvents (developers). Spatial resolution of the order of 200 nm is reported and a contrast of 2.2 is achieved. The novelty of this work is that epoxy based materials, which have enhanced thermomechanical stability with respect to the more usual acrylic based resins, are directly nanopatterned for the first time by electron beam (EB) and/or x-ray beam radiation exposure without the aid of catalysts for polymerization. In contrast to common resists that are sacrificial layers of the fabrication process, direct patternable sol-gel hybrids constitute the final material of the devices. In fact, an example of doping with a light emitting dye is reported together with the achievement of directly patterned structures by EBL and XRL.

  1. Hybrid CIS-DFT method to study electric field effects on electronic excited states of ethylene

    Institute of Scientific and Technical Information of China (English)

    Ma Mei-Zhong; Zhu Zheng-He; Chen Xiao-Jun; Xu Guo-Liang; Zhang Yong-Bin; Mao Hua-Ping; Shen Xiao-Hong

    2005-01-01

    The present work is devoted to the study of the effects of external dipole electric field on the molecular structure of ethylene using a hybrid method which combines the single-excitation configuration interactions (CIS) with density functional theory (DFT), i.e. CIS-DFT(B3LYP). It is found that the effects of electric dipole field on the molecular geometry (D2h, D2d and C2v), dipole moment, transition dipole moment, polarizability and, particularly, excitation energy of ethylene are remarkable. The advantages of the hybrid CIS-DFT method are that it can determine the symmetry of molecule and the correct order of excitation as well as the Molecular Orbital (MO) electron configuration;thereby the electronic excitation states of ethylene are easily derived, and most of them are in agreement with those obtained in experiments or references. It may be the first time the effects of external electric field on ethylene molecule have been considered. Compared with other ab initio methods, the CIS-DFT method is relatively accurate and low cost in computation. We expect that it can be used to study other closed-shell molecules.

  2. Quantitative determination of the mineral distribution in different collagen zones of calcifying tendon using high voltage electron microscopic tomography

    Science.gov (United States)

    McEwen, B. F.; Song, M. J.; Landis, W. J.

    1991-01-01

    High voltage electron microscopic tomography was used to make the first quantitative determination of the distribution of mineral between different regions of collagen fibrils undergoing early calcification in normal leg tendons of the domestic turkey, Meleagris gallopavo. The tomographic 3-D reconstruction was computed from a tilt series of 61 different views spanning an angular range of +/- 60 degrees in 2 degrees intervals. Successive applications of an interactive computer operation were used to mask the collagen banding pattern of either hole or overlap zones into separate versions of the reconstruction. In such 3-D volumes, regions specified by the mask retained their original image density while the remaining volume was set to background levels. This approach was also applied to the mineral crystals present in the same volumes to yield versions of the 3-D reconstructions that were masked for both the crystal mass and the respective collagen zones. Density profiles from these volumes contained a distinct peak corresponding only to the crystal mass. A comparison of the integrated density of this peak from each profile established that 64% of the crystals observed were located in the collagen hole zones and 36% were found in the overlap zones. If no changes in crystal stability occur once crystals are formed, this result suggests the possibilities that nucleation of mineral is preferentially and initially associated with the hole zones, nucleation occurs more frequently in the hole zones, the rate of crystal growth is more rapid in the hole zones, or a combination of these alternatives. All lead to the conclusion that the overall accumulation of mineral mass is predominant in the collagen hole zones compared to overlap zones during early collagen fibril calcification.

  3. Nucleotide divergence vs. gene expression differentiation: comparative transcriptome sequencing in natural isolates from the carrion crow and its hybrid zone with the hooded crow.

    Science.gov (United States)

    Wolf, Jochen B W; Bayer, Till; Haubold, Bernhard; Schilhabel, Markus; Rosenstiel, Philip; Tautz, Diethard

    2010-03-01

    Recent advances in sequencing technology promise to provide new strategies for studying population differentiation and speciation phenomena in their earliest phases. We focus here on the black carrion crow (Corvus [corone] corone), which forms a zone of hybridization and overlap with the grey coated hooded crow (Corvus [corone] cornix). However, although these semispecies are taxonomically distinct, previous analyses based on several types of genetic markers did not reveal significant molecular differentiation between them. We here corroborate this result with sequence data obtained from a set of 25 nuclear intronic loci. Thus, the system represents a case of a very early phase of species divergence that requires new molecular approaches for its description. We have therefore generated RNAseq expression profiles using barcoded massively parallel pyrosequencing of brain mRNA from six individuals of the carrion crow and five individuals from a hybrid zone with the hooded crow. We obtained 856 675 reads from two runs, with average read length of 270 nt and coverage of 8.44. Reads were assembled de novo into 19 552 contigs, 70% of which could be assigned to annotated genes in chicken and zebra finch. This resulted in a total of 7637 orthologous genes and a core set of 1301 genes that could be compared across all individuals. We find a clear clustering of expression profiles for the pure carrion crow animals and disperse profiles for the animals from the hybrid zone. These results suggest that gene expression differences may indeed be a sensitive indicator of initial species divergence.

  4. Nonuniform sampling schemes of the Brillouin zone for many-electron perturbation-theory calculations in reduced dimensionality

    Science.gov (United States)

    da Jornada, Felipe H.; Qiu, Diana Y.; Louie, Steven G.

    2017-01-01

    First-principles calculations based on many-electron perturbation theory methods, such as the ab initio G W and G W plus Bethe-Salpeter equation (G W -BSE) approach, are reliable ways to predict quasiparticle and optical properties of materials, respectively. However, these methods involve more care in treating the electron-electron interaction and are considerably more computationally demanding when applied to systems with reduced dimensionality, since the electronic confinement leads to a slower convergence of sums over the Brillouin zone due to a much more complicated screening environment that manifests in the "head" and "neck" elements of the dielectric matrix. Here we present two schemes to sample the Brillouin zone for G W and G W -BSE calculations: the nonuniform neck subsampling method and the clustered sampling interpolation method, which can respectively be used for a family of single-particle problems, such as G W calculations, and for problems involving the scattering of two-particle states, such as when solving the BSE. We tested these methods on several few-layer semiconductors and graphene and show that they perform a much more efficient sampling of the Brillouin zone and yield two to three orders of magnitude reduction in the computer time. These two methods can be readily incorporated into several ab initio packages that compute electronic and optical properties through the G W and G W -BSE approaches.

  5. Highly transparent, low-haze, hybrid cellulose nanopaper as electrodes for flexible electronics

    Science.gov (United States)

    Xu, Xuezhu; Zhou, Jian; Jiang, Long; Lubineau, Gilles; Ng, Tienkhee; Ooi, Boon S.; Liao, Hsien-Yu; Shen, Chao; Chen, Long; Zhu, J. Y.

    2016-06-01

    Paper is an excellent candidate to replace plastics as a substrate for flexible electronics due to its low cost, renewability and flexibility. Cellulose nanopaper (CNP), a new type of paper made of nanosized cellulose fibers, is a promising substrate material for transparent and flexible electrodes due to its potentially high transparency and high mechanical strength. Although CNP substrates can achieve high transparency, they are still characterized by high diffuse transmittance and small direct transmittance, resulting in high optical haze of the substrates. In this study, we proposed a simple methodology for large-scale production of high-transparency, low-haze CNP comprising both long cellulose nanofibrils (CNFs) and short cellulose nanocrystals (CNCs). By varying the CNC/CNF ratio in the hybrid CNP, we could tailor its total transmittance, direct transmittance and diffuse transmittance. By increasing the CNC content, the optical haze of the hybrid CNP could be decreased and its transparency could be increased. The direct transmittance and optical haze of the CNP were 75.1% and 10.0%, respectively, greatly improved from the values of previously reported CNP (31.1% and 62.0%, respectively). Transparent, flexible electrodes were fabricated by coating the hybrid CNP with silver nanowires (AgNWs). The electrodes showed a low sheet resistance (minimum 1.2 Ω sq-1) and a high total transmittance (maximum of 82.5%). The electrodes were used to make a light emitting diode (LED) assembly to demonstrate their potential use in flexible displays.Paper is an excellent candidate to replace plastics as a substrate for flexible electronics due to its low cost, renewability and flexibility. Cellulose nanopaper (CNP), a new type of paper made of nanosized cellulose fibers, is a promising substrate material for transparent and flexible electrodes due to its potentially high transparency and high mechanical strength. Although CNP substrates can achieve high transparency, they are

  6. Single electron tunneling in large scale nanojunction arrays with bisferrocene-nanoparticle hybrids

    Science.gov (United States)

    Karmakar, Shilpi; Kumar, Susmit; Marzo, Pasquale; Primiceri, Elisabetta; di Corato, Riccardo; Rinaldi, Ross; Cozzi, Pier Giorgio; Bramanti, Alessandro Paolo; Maruccio, Giuseppe

    2012-03-01

    We report on the fabrication and single electron tunneling behaviour of large scale arrays of nanogap electrodes bridged by bisferrocene-gold nanoparticle hybrids (BFc-AuNP). Coulomb staircase was observed in the low temperature current-voltage curves measured on the junctions with asymmetric tunnel barriers. On the other hand, junctions with symmetric tunneling barrier exhibited mere nonlinear current voltage characteristics without discrete staircase. The experimental results agreed well with simulations based on the orthodox theory. The junction resistance showed thermally activated conduction behaviour at higher temperature. The overall voltage and temperature dependent results show that the transport behaviour of the large arrays of single particle devices obtained by a facile optical lithography and chemical etching process corresponds with the behaviour of single particle devices fabricated by other techniques like e-beam lithography and mechanical breaking methods.We report on the fabrication and single electron tunneling behaviour of large scale arrays of nanogap electrodes bridged by bisferrocene-gold nanoparticle hybrids (BFc-AuNP). Coulomb staircase was observed in the low temperature current-voltage curves measured on the junctions with asymmetric tunnel barriers. On the other hand, junctions with symmetric tunneling barrier exhibited mere nonlinear current voltage characteristics without discrete staircase. The experimental results agreed well with simulations based on the orthodox theory. The junction resistance showed thermally activated conduction behaviour at higher temperature. The overall voltage and temperature dependent results show that the transport behaviour of the large arrays of single particle devices obtained by a facile optical lithography and chemical etching process corresponds with the behaviour of single particle devices fabricated by other techniques like e-beam lithography and mechanical breaking methods. Electronic supplementary

  7. Contribution of interlayer hybridization to the electronic structure in iron pnictides: a study of EELS and first-principles calculations.

    Science.gov (United States)

    Ma, Chao; Yang, Huaixin; Tian, Huanfang; Shi, Honglong; Wang, Zhiwei; Li, Jianqi

    2013-03-20

    Using electron energy loss spectroscopy (EELS) measurements and first-principles electronic structure calculations, the significant interlayer hybridization between the insulating layers (ReO or Ba) and the conducting FeAs layers was investigated in the layered iron pnictides, which is quite different from the case in the cuprate superconductors. This interlayer hybridization would result in an increase in the bandwidth near the Fermi level and interorbital charge transfer in the Fe 3d orbitals, which subsequently leads to a decrease in the Fe local moment and the modification of the Fermi surface topology. Therefore, a three-dimensional character of the electronic structure due to the interlayer hybridization is expected, as observed in previous experiments. These findings indicate that reduced dimensionality is no longer a necessary condition in the search for high-T(c) superconductors in iron pnictides.

  8. Single-Particle Cryo-EM and 3D Reconstruction of Hybrid Nanoparticles with Electron-Dense Components.

    Science.gov (United States)

    Yu, Guimei; Yan, Rui; Zhang, Chuan; Mao, Chengde; Jiang, Wen

    2015-10-01

    Single-particle cryo-electron microscopy (cryo-EM), accompanied with 3D reconstruction, is a broadly applicable tool for the structural characterization of macromolecules and nanoparticles. Recently, the cryo-EM field has pushed the limits of this technique to higher resolutions and samples of smaller molecular mass, however, some samples still present hurdles to this technique. Hybrid particles with electron-dense components, which have been studied using single-particle cryo-EM yet with limited success in 3D reconstruction due to the interference caused by electron-dense elements, constitute one group of such challenging samples. To process such hybrid particles, a masking method is developed in this work to adaptively remove pixels arising from electron-dense portions in individual projection images while maintaining maximal biomass signals for subsequent 2D alignment, 3D reconstruction, and iterative refinements. As demonstrated by the success in 3D reconstruction of an octahedron DNA/gold hybrid particle, which has been previously published without a 3D reconstruction, the devised strategy that combines adaptive masking and standard single-particle 3D reconstruction approach has overcome the hurdle of electron-dense elements interference, and is generally applicable to cryo-EM structural characterization of most, if not all, hybrid nanomaterials with electron-dense components.

  9. Electronic band structure effects in monolayer, bilayer, and hybrid graphene structures

    Science.gov (United States)

    Puls, Conor

    Since its discovery in 2005, graphene has been the focus of intense theoretical and experimental study owing to its unique two-dimensional band structure and related electronic properties. In this thesis, we explore the electronic properties of graphene structures from several perspectives including the magnetoelectrical transport properties of monolayer graphene, gap engineering and measurements in bilayer graphene, and anomalous quantum oscillation in the monolayer-bilayer graphene hybrids. We also explored the device implications of our findings, and the application of some experimental techniques developed for the graphene work to the study of a complex oxide, Ca3Ru2O7, exhibiting properties of strongly correlated electrons. Graphene's high mobility and ballistic transport over device length scales, make it suitable for numerous applications. However, two big challenges remain in the way: maintaining high mobility in fabricated devices, and engineering a band gap to make graphene compatible with logical electronics and various optical devices. We address the first challenge by experimentally evaluating mobilities in scalable monolayer graphene-based field effect transistors (FETs) and dielectric-covered Hall bars. We find that the mobility is limited in these devices, and is roughly inversely proportional to doping. By considering interaction of graphene's Dirac fermions with local charged impurities at the interface between graphene and the top-gate dielectric, we find that Coulomb scattering is responsible for degraded mobility. Even in the cleanest devices, a band gap is still desirable for electronic applications of graphene. We address this challenge by probing the band structure of bilayer graphene, in which a field-tunable energy band gap has been theoretically proposed. We use planar tunneling spectroscopy of exfoliated bilayer graphene flakes demonstrate both measurement and control of the energy band gap. We find that both the Fermi level and

  10. Fusion zone microstructure and porosity in electron beam welds of an α+β titanium alloy

    Science.gov (United States)

    Mohandas, T.; Banerjee, D.; Kutumba Rao, V. V.

    1999-03-01

    The effect of electron beam welding parameters on fusion zone (FZ) microstructure and porosity in a Ti -6.8 Al -3.42 Mo -1.9 Zr -0.21 Si alloy (Russian designation VT 9) has been investigated. It has been observed that the FZ grain width increased continuously with increase in heat input when the base metal was in the β heat-treated condition, while in the α+β heat-treated base metal welds, the FZ grain width increased only after a threshold energy input. The difference is attributed to both the weld thermal cycle and the pinning effect of equiaxed primary alpha on grain growth in the heat-affected zone (HAZ) of α+β heat-treated base metal. Postweld heat treatment (PWHT) in the subtransus and supertransus regions did not alter the columnar grain morphology in the FZ, possibly due to the lack of enough driving force for the formation of new grains by the breaking up of the columnar grains and grain boundary movement for grain growth. As the PWHTs were conducted in a furnace, the role of thermal gradients can be ruled out. Intragranular microstructure in the aswelded condition consisted of hexagonal martensite. The scale of the martensite laths depended on welding speed. The highest porosity was observed at intermediate welding speeds. At low speeds, a majority of pores formed at the fusion boundary, while at high speeds, occurrence of porosity was maximum at the weld center. The trends on porosity can be explained on the basis of solubility of hydrogen in titanium as a function of temperature and the influence of weld thermal cycle on nucleation, growth, and escape of hydrogen gas bubbles. The porosity at slow welding speeds is low because sufficient time exists for the nucleation, growth, and escape of hydrogen gas bubbles, while insufficient time exists for the nucleation of gas bubbles at high welding speeds. The effect of pickling of joint surface, vacuum annealing of the base metal, and successive remelting of the weld metal has also been investigated.

  11. Stability of hybrid modes of a single-component electron plasma containing an admixture of background gas ions

    Science.gov (United States)

    Yeliseyev, Yu. N.

    2014-05-01

    The spectrum of eigenmodes of a waveguide completely filled with a cold electron plasma containing a small admixture of ions produced due to electron-impact ionization of background gas atoms is calculated numerically. The calculations were performed within the entire range of allowable values of the radial electric and longitudinal magnetic fields for both magnetized and unmagnetized ions by using the earlier derived nonlocal dispersion relation [Plasma Phys. Rep. 36, 563 (2010)]. The spectrum consists of three families of electron modes with frequencies equal to the Doppler-shifted upper and lower hybrid frequencies and modified ion cyclotron (MIC) modes. When the Doppler shift caused by electron rotation in the crossed electric and magnetic fields compensates for the hybrid frequency, the electron modes become low-frequency modes and interact with the ion modes. For m = 1, only the lower hybrid modes can be low-frequency ones, whereas at m ≥ 2, both lower and upper hybrid modes can be low-frequency ones. The spectrum of modes having the azimuthal number m = 2 is thoroughly analyzed. It is shown that, in this case, the lower hybrid modes behave similar to the m = 1 modes. The dispersion curves of the upper hybrid modes intersect with all harmonics of the MIC frequency (positive, negative, and zero) and are unstable in the vicinities of the intersections. The maximum value of the instability growth rate is several times higher than the ion plasma frequency. The MIC modes are unstable within a wide range of the field strengths, and their growth rates are two orders of magnitude slower. Instabilities are caused by the relative motion of electrons and ions (the transverse current) and the anisotropy of the ion distribution function.

  12. Donor–acceptor graphene-based hybrid materials facilitating photo-induced electron-transfer reactions

    Directory of Open Access Journals (Sweden)

    Anastasios Stergiou

    2014-09-01

    Full Text Available Graphene research and in particular the topic of chemical functionalization of graphene has exploded in the last decade. The main aim is to increase the solubility and thereby enhance the processability of the material, which is otherwise insoluble and inapplicable for technological applications when stacked in the form of graphite. To this end, initially, graphite was oxidized under harsh conditions to yield exfoliated graphene oxide sheets that are soluble in aqueous media and amenable to chemical modifications due to the presence of carboxylic acid groups at the edges of the lattice. However, it was obvious that the high-defect framework of graphene oxide cannot be readily utilized in applications that are governed by charge-transfer processes, for example, in solar cells. Alternatively, exfoliated graphene has been applied toward the realization of some donor–acceptor hybrid materials with photo- and/or electro-active components. The main body of research regarding obtaining donor–acceptor hybrid materials based on graphene to facilitate charge-transfer phenomena, which is reviewed here, concerns the incorporation of porphyrins and phthalocyanines onto graphene sheets. Through illustrative schemes, the preparation and most importantly the photophysical properties of such graphene-based ensembles will be described. Important parameters, such as the generation of the charge-separated state upon photoexcitation of the organic electron donor, the lifetimes of the charge-separation and charge-recombination as well as the incident-photon-to-current efficiency value for some donor–acceptor graphene-based hybrids, will be discussed.

  13. Highly transparent, low-haze, hybrid cellulose nanopaper as electrodes for flexible electronics

    KAUST Repository

    Xu, Xuezhu

    2016-06-01

    Paper is an excellent candidate to replace plastics as a substrate for flexible electronics due to its low cost, renewability and flexibility. Cellulose nanopaper (CNP), a new type of paper made of nanosized cellulose fibers, is a promising substrate material for transparent and flexible electrodes due to its potentially high transparency and high mechanical strength. Although CNP substrates can achieve high transparency, they are still characterized by high diffuse transmittance and small direct transmittance, resulting in high optical haze of the substrates. In this study, we proposed a simple methodology for large-scale production of high-transparency, low-haze CNP comprising both long cellulose nanofibrils (CNFs) and short cellulose nanocrystals (CNCs). By varying the CNC/CNF ratio in the hybrid CNP, we could tailor its total transmittance, direct transmittance and diffuse transmittance. By increasing the CNC content, the optical haze of the hybrid CNP could be decreased and its transparency could be increased. The direct transmittance and optical haze of the CNP were 75.1% and 10.0%, respectively, greatly improved from the values of previously reported CNP (31.1% and 62.0%, respectively). Transparent, flexible electrodes were fabricated by coating the hybrid CNP with silver nanowires (AgNWs). The electrodes showed a low sheet resistance (minimum 1.2 Ω sq-1) and a high total transmittance (maximum of 82.5%). The electrodes were used to make a light emitting diode (LED) assembly to demonstrate their potential use in flexible displays. © 2016 The Royal Society of Chemistry.

  14. Making hybrid [n]-rotaxanes as supramolecular arrays of molecular electron spin qubits

    Science.gov (United States)

    Fernandez, Antonio; Ferrando-Soria, Jesus; Pineda, Eufemio Moreno; Tuna, Floriana; Vitorica-Yrezabal, Iñigo J.; Knappke, Christiane; Ujma, Jakub; Muryn, Christopher A.; Timco, Grigore A.; Barran, Perdita E.; Ardavan, Arzhang; Winpenny, Richard E. P.

    2016-01-01

    Quantum information processing (QIP) would require that the individual units involved--qubits--communicate to other qubits while retaining their identity. In many ways this resembles the way supramolecular chemistry brings together individual molecules into interlocked structures, where the assembly has one identity but where the individual components are still recognizable. Here a fully modular supramolecular strategy has been to link hybrid organic-inorganic [2]- and [3]-rotaxanes into still larger [4]-, [5]- and [7]-rotaxanes. The ring components are heterometallic octanuclear [Cr7NiF8(O2CtBu)16]- coordination cages and the thread components template the formation of the ring about the organic axle, and are further functionalized to act as a ligand, which leads to large supramolecular arrays of these heterometallic rings. As the rings have been proposed as qubits for QIP, the strategy provides a possible route towards scalable molecular electron spin devices for QIP. Double electron-electron resonance experiments demonstrate inter-qubit interactions suitable for mediating two-qubit quantum logic gates.

  15. Enhancing Intrinsic Stability of Hybrid Perovskite Solar Cell by Strong, yet Balanced, Electronic Coupling

    Science.gov (United States)

    El-Mellouhi, Fedwa; Bentria, El Tayeb; Rashkeev, Sergey N.; Kais, Sabre; Alharbi, Fahhad H.

    2016-07-01

    In the past few years, the meteoric development of hybrid organic–inorganic perovskite solar cells (PSC) astonished the community. The efficiency has already reached the level needed for commercialization; however, the instability hinders its deployment on the market. Here, we report a mechanism to chemically stabilize PSC absorbers. We propose to replace the widely used methylammonium cation (CH3NH3+) by alternative molecular cations allowing an enhanced electronic coupling between the cation and the PbI6 octahedra while maintaining the band gap energy within the suitable range for solar cells. The mechanism exploits establishing a balance between the electronegativity of the materials’ constituents and the resulting ionic electrostatic interactions. The calculations demonstrate the concept of enhancing the electronic coupling, and hence the stability, by exploring the stabilizing features of CH3PH3+, CH3SH2+, and SH3+ cations, among several other possible candidates. Chemical stability enhancement hence results from a strong, yet balanced, electronic coupling between the cation and the halides in the octahedron. This shall unlock the hindering instability problem for PSCs and allow them to hit the market as a serious low-cost competitor to silicon based solar cell technologies.

  16. Enhancing Intrinsic Stability of Hybrid Perovskite Solar Cell by Strong, yet Balanced, Electronic Coupling

    Science.gov (United States)

    El-Mellouhi, Fedwa; Bentria, El Tayeb; Rashkeev, Sergey N.; Kais, Sabre; Alharbi, Fahhad H.

    2016-01-01

    In the past few years, the meteoric development of hybrid organic–inorganic perovskite solar cells (PSC) astonished the community. The efficiency has already reached the level needed for commercialization; however, the instability hinders its deployment on the market. Here, we report a mechanism to chemically stabilize PSC absorbers. We propose to replace the widely used methylammonium cation (CH3NH3+) by alternative molecular cations allowing an enhanced electronic coupling between the cation and the PbI6 octahedra while maintaining the band gap energy within the suitable range for solar cells. The mechanism exploits establishing a balance between the electronegativity of the materials’ constituents and the resulting ionic electrostatic interactions. The calculations demonstrate the concept of enhancing the electronic coupling, and hence the stability, by exploring the stabilizing features of CH3PH3+, CH3SH2+, and SH3+ cations, among several other possible candidates. Chemical stability enhancement hence results from a strong, yet balanced, electronic coupling between the cation and the halides in the octahedron. This shall unlock the hindering instability problem for PSCs and allow them to hit the market as a serious low-cost competitor to silicon based solar cell technologies. PMID:27457130

  17. Occurrence characteristics of outer zone relativistic electron butterfly distribution: A survey of Van Allen Probes REPT measurements

    Science.gov (United States)

    Ni, Binbin; Zou, Zhengyang; Li, Xinlin; Bortnik, Jacob; Xie, Lun; Gu, Xudong

    2016-06-01

    Using Van Allen Probes Relativistic Electron Proton Telescope (REPT) pitch angle resolved electron flux data from September 2012 to March 2015, we investigate in detail the global occurrence pattern of equatorial (|λ| ≤ 3°) butterfly distribution of outer zone relativistic electrons and its potential correlation with the solar wind dynamic pressure. The statistical results demonstrate that these butterfly distributions occur with the highest occurrence rate ~ 80% at ~ 20-04 magnetic local time (MLT) and L > ~ 5.5 and with the second peak (> ~ 50%) at ~ 11-15 MLT of lower L shells ~ 4.0. They can also extend to L = 3.5 and to other MLT intervals but with the occurrence rates predominantly butterfly distributions are likely to peak between 58° and 79° for L = 4.0 and 5.0 and between 37° and 58° for L = 6.0, regardless of the level of solar wind dynamic pressure. Relativistic electron butterfly distributions at L = 4.0 also exhibit a pronounced day-night asymmetry in response to the Pdyn variations. Compared to the significant L shell and MLT dependence of the global occurrence pattern, outer zone relativistic electron butterfly distributions show much less but still discernable sensitivity to Pdyn, geomagnetic activity level, and electron energy, the full understanding of which requires future attempts of detailed simulations that combine and differentiate underlying physical mechanisms of the geomagnetic field asymmetry and scattering by various magnetospheric waves.

  18. Design guidelines for use of adhesives in hybrid microcircuits. [for electronic equipment in space applications

    Science.gov (United States)

    Caruso, S. V.; Perkins, K. L.; Licari, J. J.

    1973-01-01

    Although it is generally accepted that the use of adhesives in the assembly of hybrid microcircuits offers advantages over other bonding methods, there currently does not exist a set of guidelines for the selection of adhesives which will insure that hybrid microcircuits assembled with them will meet the long use-life, high-reliability requirements of electronic equipment for space applications. This study was directed to the identification of the properties of electrically insulative adhesives that potentially could cause problems in such an application, and to the development of evaluation tests to quantify these properties and thus form the basis for establishing suitable guidelines and, ultimately, specifications. Bond strength, outgassing after cure, and corrosivity were selected for detailed attention since they are considered to be especially critical. Introductory discussion includes enumeration and brief comments on the properties of adhesives considered to be important for the proposed application, a general review of polymeric types of adhesives, and identification of the major types of adhesives commercially available and specifically designed for microelectronic use. The specific tests developed to evaluate bond strength, outgassing after cure, and corrosivity are discussed in detail, and comparative results obtained for selected adhesives representative of the major types are given.

  19. Electron beam energy stabilization using a neural network hybrid controller at the Australian Synchrotron Linac.

    Energy Technology Data Exchange (ETDEWEB)

    Meier, E.; Morgan, M. J.; Biedron, S. G.; LeBlanc, G.; Wu, J. (OTD-ESE); (Monash Univ.); (Australian Synchrotron Project); (SLAC National Accelerator Lab.)

    2009-01-01

    This paper describes the implementation of a neural network hybrid controller for energy stabilization at the Australian Synchrotron Linac. The structure of the controller consists of a neural network (NNET) feed forward control, augmented by a conventional Proportional-Integral (PI) feedback controller to ensure stability of the system. The system is provided with past states of the machine in order to predict its future state, and therefore apply appropriate feed forward control. The NNET is able to cancel multiple frequency jitter in real-time. When it is not performing optimally due to jitter changes, the system can successfully be augmented by the PI controller to attenuate the remaining perturbations. With a view to control the energy and bunch length at the FERMI{at}Elettra Free Electron Laser (FEL), the present study considers a neural network hybrid feed forward-feedback type of control to rectify limitations related to feedback systems, such as poor response for high jitter frequencies or limited bandwidth, while ensuring robustness of control. The Australian Synchrotron Linac is equipped with a beam position monitor (BPM), that was provided by Sincrotrone Trieste from a former transport line thus allowing energy measurements and energy control experiments. The present study will consequently focus on correcting energy jitter induced by variations in klystron phase and voltage.

  20. Power sources for portable electronics and hybrid cars: lithium batteries and fuel cells.

    Science.gov (United States)

    Scrosati, Bruno

    2005-01-01

    The activities in progress in our laboratory for the development of batteries and fuel cells for portable electronics and hybrid car applications are reviewed and discussed. In the case of lithium batteries, the research has been mainly focused on the characterization of new electrode and electrolyte materials. Results related to disordered carbon anodes and improved, solvent-free, as well as gel-type, polymer electrolytes are particularly stressed. It is shown that the use of proper gel electrolytes, in combination with suitable electrode couples, allows the development of new types of safe, reliable, and low-cost lithium ion batteries which appear to be very promising power sources for hybrid vehicles. Some of the technologies proven to be successful in the lithium battery area are readapted for use in fuel cells. In particular, this approach has been followed for the preparation of low-cost and stable protonic membranes to be proposed as an alternative to the expensive, perfluorosulfonic membranes presently used in polymer electrolyte membrane fuel cells (PEMFCs). Copyright 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc

  1. 3D hybrid simulations with gyrokinetic particle ions and fluid electrons

    Energy Technology Data Exchange (ETDEWEB)

    Belova, E.V.; Park, W.; Fu, G.Y. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Strauss, H.R. [New York Univ., NY (United States); Sugiyama, L.E. [Massachusetts Inst. of Tech., Cambridge, MA (United States)

    1998-12-31

    The previous hybrid MHD/particle model (MH3D-K code) represented energetic ions as gyrokinetic (or drift-kinetic) particles coupled to MHD equations using the pressure or current coupling scheme. A small energetic to bulk ion density ratio was assumed, n{sub h}/n{sub b} {much_lt} 1, allowing the neglect of the energetic ion perpendicular inertia in the momentum equation and the use of MHD Ohm`s law E = {minus}v{sub b} {times} B. A generalization of this model in which all ions are treated as gyrokinetic/drift-kinetic particles and fluid description is used for the electron dynamics is considered in this paper.

  2. More stable hybrid organic solar cells deposited on amorphous Si electron transfer layer

    Energy Technology Data Exchange (ETDEWEB)

    Samiee, Mehran; Modtland, Brian; Dalal, Vikram L., E-mail: vdalal@iastate.edu [Iowa State University, Dept. of Electrical and Computer Engineering, Ames, Iowa 50011 (United States); Aidarkhanov, Damir [Nazarbayev University, Astana (Kazakhstan)

    2014-05-26

    We report on defect densities, performance, and stability of organic/inorganic hybrid solar cells produced using n-doped inorganic amorphous silicon-carbide layers as the electron transport layer (ETL). The organic material was poly-3-hexyl-thiophene (P3HT) and heterojunction was formed using phenyl-C{sub 71}-Butyric-Acid-Methyl Ester (PCBM). For comparison, inverted solar cells fabricated using Cs{sub 2}CO{sub 3} as ETL were fabricated. Defect densities and subgap quantum efficiency curves were found to be nearly identical for both types of cells. The cells were subjected to 2xsun illumination and it was found that the cells produced using doped a-Si as ETL were much more stable than the cells produced using Cs{sub 2}CO{sub 3}.

  3. The Detection of Defects in Optical Fibers Using a Hybrid Opto-electronic Correlator

    Institute of Scientific and Technical Information of China (English)

    LIU Yange; LIU Wei; ZHANG Yimo; ZHOU Ge

    2000-01-01

    A hybrid opto-electronic correlator for detecting defects in optical fibers is proposed. After the light from a He-Ne laser being expanded and filtered it is not collimated but directly passes a Fourier transform lens and illuminates a reference fiber and a test fiber at the same input plane. The Fourier transform spectrum of the two fibers is therefore obtained at the rear focal plane of the lens, where it is sampled via a CCD array connected with a computer through a frame grabber. The computer performs filter, inverse Fourier transform and setting threshold operation on classification. The system is an equivalent of joint transform correlator with a Fourier lens of long focal length. The experiment results for optical fibers having incoordinate defects are presented. The results indicate that the system can be used for fiber defect detection, and has the advantages of high identification, compact configuration, easy adjustment and flexible manipulation.

  4. Cross-Linkable and Dual Functional Hybrid Polymeric Electron Transporting Layer for High-Performance Inverted Polymer Solar Cells.

    Science.gov (United States)

    Dong, Sheng; Hu, Zhicheng; Zhang, Kai; Yin, Qingwu; Jiang, Xiaofang; Huang, Fei; Cao, Yong

    2017-06-20

    A cross-linkable dual functional polymer hybrid electron transport layer (ETL) is developed by simply adding an amino-functionalized polymer dopant (PN4N) and a light crosslinker into a commercialized n-type semiconductor (N2200) matrix. It is found that the resulting hybrid ETL not only has a good solvent resistance, facilitating multilayers device fabrication but also exhibits much improved electron transporting/extraction properties due to the doping between PN4N and N2200. As a result, by using PTB7-Th:PC71 BM blend as an active layer, the inverted device based on the hybrid ETL can yield a prominent power conversion efficiency of around 10.07%. More interestingly, photovoltaic property studies of bilayer devices suggest that the absorption of the hybrid ETL contributes to photocurrent and hence the hybrid ETL simultaneously acts as both cathode interlayer material and an electron acceptor. The resulting inverted polymer solar cells function like a novel device architectures with a combination of a bulk heterojunction device and miniature bilayer devices. This work provides new insights on function of ETLs and may be open up a new direction for the design of new ETL materials and novel device architectures to further improve device performance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Analysis of Upper Hybrid Wave Growth Rates From Measured Electron Distributions; An Encounter With the Source of Auroral Roar

    Science.gov (United States)

    Bounds, S. R.; Kletzing, C. A.; Labelle, J. W.; Samara, M.; Yoon, P. H.

    2005-12-01

    In January of 2003, the High Bandwidth Auroral Rocket (HIBAR) passed through two regions of strong upper hybrid wave emission associated with the approximate matching of the upper hybrid frequency to twice the electron cyclotron frequency (fuh = 2 fce) (Samara 2004) These types of emission are believed to be the source of the HF auroral roar often observed by ground based receivers. The current model theorizes that the free space 0-mode waves observed on the ground are produced through mode conversion of strong emission of Z-mode, or upper hybrid waves. The relativistic electron cyclotron maser exhibits significant growth rates for the Z-mode when the local upper hybrid frequency is just below (~1%) twice the electron cyclotron frequency and with the appropriately unstable electron distribution (Yoon 1996, Yoon 1998, Yoon 2000). Though auroral roar is frequently observed from the ground, the source region has rarely been identified in-situ and even more rarely with sufficient bandwidth to analyze the underlying physical processes. Analysis of the electron distributions from HIBAR show good agreement with the theoretical distributions used by Yoon:98. HIBAR encountered three separate regions where fuh ≍ 2 fce, two of these regions include strong upper hybrid emission, while the third is void of upper hybrid wave activity. The measured particle distributions demonstrate that, in the two regions with wave emission, the relativistic electron cyclotron maser instability produces Z mode wave growth rates at least an order of magnitude greater than the electron collision frequency. In the third region without wave emission, the growth rates are much smaller in both amplitude and the extent of occurance. Samara, M., J. LaBelle, C. A. Kletzing, and S. R. Bounds, Rocket observations of structured upper hybrid wave at fuh=2fce, Geophys. Res. Lett., 31, L22804, doi:10.1029/2004GL021043. Yoon, P. H., A. T. Weatherwax, and T. J. Rosenberg, Lower ionospheric cyclotron maser

  6. Electronic and vibrational properties of transition metal-oxides: Comparison of GGA, GGA + U, and hybrid approaches

    Science.gov (United States)

    Pandey, Sumeet C.; Xu, Xu; Williamson, Izaak; Nelson, Eric B.; Li, Lan

    2017-02-01

    We estimate the Hubbard parameters for density-functional-theory (DFT) + U calculations of ZrO2, HfO2, TiO2, and NiO based on calibrating the electronic structure obtained from hybrid functional methods. The electronic density of states is used to assess the parameters and the values thus derived are employed for the full electron and phonon dispersion comparisons. The resulting values account for experimental band gaps and electron correlations that are computationally much less demanding to treat within the simpler DFT + U framework than with the typically more accurate yet expensive hybrid functional methods. Limitations of +U scheme is indicated towards describing TiO2 and HfO2 phase-stability.

  7. Hybrid nanowire ion-to-electron transducers for integrated bioelectronic circuitry (Conference Presentation)

    Science.gov (United States)

    Carrad, Damon J.; Mostert, Bernard; Meredith, Paul; Micolich, Adam P.

    2016-09-01

    A key task in bioelectronics is the transduction between ionic/protonic signals and electronic signals at high fidelity. This is a considerable challenge since the two carrier types exhibit intrinsically different physics. We present our work on a new class of organic-inorganic transducing interface utilising semiconducting InAs and GaAs nanowires directly gated with a proton transporting hygroscopic polymer consisting of undoped polyethylene oxide (PEO) patterned to nanoscale dimensions by a newly developed electron-beam lithography process [1]. Remarkably, we find our undoped PEO polymer electrolyte gate dielectric [2] gives equivalent electrical performance to the more traditionally used LiClO4-doped PEO [3], with an ionic conductivity three orders of magnitude higher than previously reported for undoped PEO [4]. The observed behaviour is consistent with proton conduction in PEO. We attribute our undoped PEO-based devices' performance to the small external surface and high surface-to-volume ratio of both the nanowire conducting channel and patterned PEO dielectric in our devices, as well as the enhanced hydration afforded by device processing and atmospheric conditions. In addition to studying the basic transducing mechanisms, we also demonstrate high-fidelity ionic to electronic conversion of a.c. signals at frequencies up to 50 Hz. Moreover, by combining complementary n- and p-type transducers we demonstrate functional hybrid ionic-electronic circuits can achieve logic (NOT operation), and with some further engineering of the nanowire contacts, potentially also amplification. Our device structures have significant potential to be scaled towards realising integrated bioelectronic circuitry. [1] D.J. Carrad et al., Nano Letters 14, 94 (2014). [2] D.J. Carrad et al., Manuscript in preparation (2016). [3] S.H. Kim et al., Advanced Materials 25, 1822 (2013). [4] S.K. Fullerton-Shirey et al., Macromolecules 42, 2142 (2009).

  8. DISTRIBUTION OF VEGF mRNA IN BREAST CANCER WITH NONRADIOACTIVE IN SITU HYBRIDIZATION AT ELECTRON MICROSCOPIC LEVELS

    Institute of Scientific and Technical Information of China (English)

    王医术; 林; 王心蕊; 李一雷; 吴珊; 张丽红

    2002-01-01

    Object: To localize the mRNA coding for VEGF at Ultrastractural level in human breast cancer by using digoxigenin-labeled cDNA probes. Methods: Nonradio- active in situ hybridization at electron microscopic level was employed to detected VEGF mRNA in breast cancer. Result: Cancer cells and endothelial cell of angiogensis show dark color in experiment sections. No dark color can be found in control sections. Positive hybridization signals showed dark dot and were locatedin various compartments of the breast cancer cell and endothelial cell in experiment section. No labeling was observed in control sections. In experiment sections, the staining appeared concentrated in cytoplasm and nucleus of the breast cancer cell and endothelial cell. Conclusion: Nonradioactive in situ hybridization at electron microscopic level is efficient for direct observation of the target site mRNA of VEGF in the cytoplasm and nucleus.

  9. Envelope Soliton in Multi-ion Plasma and Ion-Ion Hybrid Wave Excited by Energetic Electron Beam

    Institute of Scientific and Technical Information of China (English)

    WANG De-Yu; HUANG Guang-Li

    2001-01-01

    Another envelope soliton event below the H+ gyrofrequency and localized density depletion has been discoveredin the low auroral region (~1760 kin) by the Freja satellite. This envelope soliton has a characteristic frequencyat ~190 Hz, which is also close to the resonance frequency of hydrogen ion-oxygen ion hybrid wave. This event iscorrelated in time with the observations of the sharp increase of the ratio of oxygen ion density to hydrogen andwith the electron energization along the magnetic field. A theoretical model on the ion-ion hybrid wave excitedby an energetic electron beam has also been presented. It is found that the ion-ion hybrid wave is mainly excitedby the Cherenkov instability in the auroral region.

  10. Hybrid exchange-correlation functional for accurate prediction of the electronic and structural properties of ferroelectric oxides

    OpenAIRE

    D., I. Bilc; R., Orlando; R., Shaltaf; G., M. Rignanese; J., Íñiguez; Ph., Ghosez

    2008-01-01

    Using a linear combination of atomic orbitals approach, we report a systematic comparison of various Density Functional Theory (DFT) and hybrid exchange-correlation functionals for the prediction of the electronic and structural properties of prototypical ferroelectric oxides. It is found that none of the available functionals is able to provide, at the same time, accurate electronic and structural properties of the cubic and tetragonal phases of BaTiO$_3$ and PbTiO$_3$. Some, although not al...

  11. A segmented Hybrid Photon Detector with integrated auto-triggering front-end electronics for a PET scanner

    CERN Document Server

    Chesi, Enrico Guido; Joram, C; Mathot, S; Séguinot, Jacques; Weilhammer, P; Ciocia, F; De Leo, R; Nappi, E; Vilardi, I; Argentieri, A; Corsi, F; Dragone, A; Pasqua, D

    2006-01-01

    We describe the design, fabrication and test results of a segmented Hybrid Photon Detector with integrated auto-triggering front-end electronics. Both the photodetector and its VLSI readout electronics are custom designed and have been tailored to the requirements of a recently proposed novel geometrical concept of a Positron Emission Tomograph. Emphasis is put on the PET specific features of the device. The detector has been fabricated in the photocathode facility at CERN.

  12. Surface Electronic Structure of Hybrid Organo Lead Bromide Perovskite Single Crystals

    KAUST Repository

    Komesu, Takashi

    2016-08-24

    The electronic structure and band dispersion of methylammonium lead bromide, CH3NH3PbBr3, has been investigated through a combination of angle-resolved photoemission spectroscopy (ARPES) and inverse photoemission spectroscopy (IPES), as well as theoretical modeling based on density functional theory. The experimental band structures are consistent with the density functional calculations. The results demonstrate the presence of a dispersive valence band in MAPbBr3 that peaks at the M point of the surface Brillouin zone. The results also indicate that the surface termination of the CH3NH3PbBr3 is the methylammonium bromide (CH3NH3Br) layer. We find our results support models that predict a heavier hole effective mass in the region of -0.23 to -0.26 me, along the Γ (surface Brillouin center) to M point of the surface Brillouin zone. The surface appears to be n-type as a result of an excess of lead in the surface region. © 2016 American Chemical Society.

  13. Magnon, phonon, and electron temperature profiles and the spin Seebeck effect in magnetic insulator/normal metal hybrid structures

    NARCIS (Netherlands)

    Schreier, M.; Kamra, A.; Weiler, M.; Xiao, J.; Bauer, G.E.W.; Gross, R.; Goennenwein, S.T.B.

    2013-01-01

    We calculate the phonon, electron, and magnon temperature profiles in yttrium iron garnet/platinum bilayers by diffusive theory with appropriate boundary conditions, in particular taking into account interfacial thermal resistances. Our calculations show that in thin film hybrids, the interface magn

  14. N-type polymers as electron extraction layers in hybrid perovskite solar cells with improved ambient stability

    NARCIS (Netherlands)

    Shao, S.; Chen, Z.; Fang, H. -H.; ten Brink, G. H.; Bartesaghi, D.; Adjokatse, S.; Koster, L. J. A.; Kooi, B. J.; Facchetti, A.; Loi, M. A.

    2016-01-01

    We studied three n-type polymers of the naphthalenediimide-bithiophene family as electron extraction layers (EELs) in hybrid perovskite solar cells. The recombination mechanism in these devices is found to be heavily influenced by the EEL transport properties. The maximum efficiency of the devices u

  15. Scanning electron microscopy and fluorescent in situ hybridization of experimental Brachyspira (Serpulina) pilosicoli infection in growing pigs

    DEFF Research Database (Denmark)

    Jensen, Tim Kåre; Møller, Kristian; Boye, Mette

    2000-01-01

    Two groups of six 8-week-old pigs were challenged with 1X10(9) cfu Brachyspira (Serpulina) pilosicoli or Serpulina intermedia daily for 3 consecutive days to study the pathology of porcine colonic spirochetosis by scanning electron microscopy (SEM) and fluorescent in situ hybridization (FISH...

  16. Structures of Syn-deformational Granites in the Longquanguan Shear Zone and Their Monazite Electronic Microprobe Dating

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jinjiang; ZHAO Lan; LIU Shuwen

    2006-01-01

    The Longquanguan shear zone is an important structural belt in the North China Craton,separating the underlying Fuping complex from the overlying Wutai complex. This shear zone has experienced three episodes of deformation: the first and main episode is a ductile top-to-ESE shear along the gently northwest-west dipping foliations, while the other two episodes are later collapse sliding. Prolonged granites parallel to the shear foliations make one of the main compositions of the Longquanguan shear zone. These granites experienced deformation to form mylonitic rocks when they emplaced during the first episode of deformation. Structural characters of the granites and their contacts to the country rocks indicate that these granites possibly resulted from in-situ partial remelting by shearing, i.e., they are syn-deformational granites. Monazites in these mylonitic granites are magmatic minerals and their crystallization ages may represent ages of the magmatic events, and also the ages for the main deformation of the Longquanguan shear zone. Monazite electronic microprobe dating were carried on two samples of granite, which gives multiple peak ages, among which 1,846 Ma and 1,877 Ma are the main peak ages for the two samples. These ages represent the main deformation of the Longquanguan shear zone, which is consistent with the main regional geological event at about 1,850 Ma caused by the collision between the Eastern and Western Blocks in North China. The good match between the monazite ages and the corresponding regional tectono-thermal events shows the feasibility and reliability of monazite electronic microprobe dating.

  17. Genes with Restricted Introgression in a Field Cricket (Gryllus firmus/Gryllus pennsylvanicus) Hybrid Zone Are Concentrated on the X Chromosome and a Single Autosome.

    Science.gov (United States)

    Maroja, Luana S; Larson, Erica L; Bogdanowicz, Steven M; Harrison, Richard G

    2015-08-26

    Characterizing the extent of genomic differentiation between recently diverged lineages provides an important context for understanding the early stages of speciation. When such lineages form discrete hybrid zones, patterns of differential introgression allow direct estimates of which genome regions are likely involved in speciation and local adaptation. Here we use a backcross experimental design to construct a genetic linkage map for the field crickets Gryllus firmus and Gryllus pennsylvanicus, which interact in a well-characterized hybrid zone in eastern North America. We demonstrate that loci with major allele frequency differences between allopatric populations are not randomly distributed across the genome. Instead, most are either X-linked or map to a few small autosomal regions. Furthermore, the subset of those highly differentiated markers that exhibit restricted introgression across the cricket hybrid zone are also concentrated on the X chromosome (39 of 50 loci) and in a single 7-cM region of one autosome. Although the accumulation on the sex chromosome of genes responsible for postzygotic barriers is a well-known phenomenon, less attention has been given to the genomic distribution of genes responsible for prezygotic barriers. We discuss the implications of our results for speciation, both in the context of the role of sex chromosomes and also with respect to the likely causes of heterogeneous genomic divergence. Although we do not yet have direct evidence for the accumulation of ecological, behavioral, or fertilization prezygotic barrier genes on the X chromosome, faster-X evolution could make these barriers more likely to be X-linked.

  18. 75 FR 30372 - Foreign-Trade Zone 196 Temporary/Interim Manufacturing Authority ATC Logistics & Electronics...

    Science.gov (United States)

    2010-06-01

    ... & Electronics (Cell Phone Kitting and Distribution); Notice of Approval On March 30, 2010, the Executive... & Electronics, operator of Site 2, FTZ 196, requesting temporary/interim manufacturing (T/IM) authority...

  19. 75 FR 4343 - Foreign-Trade Zone 22-Chicago, IL; Application for Manufacturing Authority; LG Electronics...

    Science.gov (United States)

    2010-01-27

    ... Electronics MobileComm USA, Inc. (Cell Phone Kitting and Distribution); Bolingbrook, IL An application has..., grantee of FTZ 22, requesting manufacturing authority on behalf of LG Electronics MobileComm USA,...

  20. Self-powered textile for wearable electronics by hybridizing fiber-shaped nanogenerators, solar cells, and supercapacitors.

    Science.gov (United States)

    Wen, Zhen; Yeh, Min-Hsin; Guo, Hengyu; Wang, Jie; Zi, Yunlong; Xu, Weidong; Deng, Jianan; Zhu, Lei; Wang, Xin; Hu, Chenguo; Zhu, Liping; Sun, Xuhui; Wang, Zhong Lin

    2016-10-01

    Wearable electronics fabricated on lightweight and flexible substrate are believed to have great potential for portable devices, but their applications are limited by the life span of their batteries. We propose a hybridized self-charging power textile system with the aim of simultaneously collecting outdoor sunshine and random body motion energies and then storing them in an energy storage unit. Both of the harvested energies can be easily converted into electricity by using fiber-shaped dye-sensitized solar cells (for solar energy) and fiber-shaped triboelectric nanogenerators (for random body motion energy) and then further stored as chemical energy in fiber-shaped supercapacitors. Because of the all-fiber-shaped structure of the entire system, our proposed hybridized self-charging textile system can be easily woven into electronic textiles to fabricate smart clothes to sustainably operate mobile or wearable electronics.

  1. Electron spin resonance dating of fault gouge from Desamangalam, Kerala: Evidence for Quaternary movement in Palghat gap shear zone

    Indian Academy of Sciences (India)

    T K Gundu Rao; C P Rajendran; George Mathew; Biju John

    2002-06-01

    The field investigations in the epicentral area of the 1994 Wadakkancheri (Desamangalam), Kerala, earthquake (M 4.3) indicate subtle, but clearly recognizable expressions of geologically recent fault zone, consisting of fracture sets showing brittle displacement and a gouge zone. The fracture zone confines to the crystalline basement, and is spatially coincident with the elongation of the isoseismals of the 1994 mainshock and a 10-km-long WNW-ESE trending topographic lineament. The preliminary results from the electron spin resonance (ESR) dating on the quartz grains from the fault gouge indicate that the last major faulting in this site occurred 430 ± 43 ka ago. The experiments on different grain sizes of quartz from the gouge showed consistent decrease in age to a plateau of low values, indicating that ESR signals in finer grains were completely zeroed at the time of faulting due to frictional heat. The results show a relatively young age for displacement on the fault that occurs within a Precambrian shear zone. Discrete reactivated faults in such areas may be characterized by low degree of activity, but considering the ESR age of the last significant faulting event, the structure at Desamangalam may be categorized as a potentially active fault capable of generating moderate earthquakes, separated by very long periods of quiescence.

  2. Organic-inorganic semiconductor hybrid systems. Structure, morphology, and electronic properties

    Energy Technology Data Exchange (ETDEWEB)

    El Helou, Mira

    2012-08-22

    This dissertation addresses the preparation and characterization of hybrid semiconducting systems combining organic with inorganic materials. Characterization methods used included to determine the structure, morphology, and thermal stability comprised X-ray diffraction (XRD), atomic force microscopy (AFM), thermal desorption spectroscopy (TDS), and X-ray photoelectron spectroscopy (XPS). One organic-inorganic semiconducting system was pentacene (C{sub 22}H{sub 14}) and zinc oxide. This interface was investigated in detail for pentacene on an oxygen-terminated zinc oxide surface, i.e. ZnO(000 anti 1). An extended study on the promising p-n junction was carried out for pentacene on ZnO with different orientations which exhibit different chemical and structural characteristics: ZnO(000 anti 1), ZnO(0001), and ZnO(10 anti 10). Moreover, the organic crystal structure of pentacene was selectively tuned by carefully choosing the substrate temperature. This defined interface with a physisorbed pentacene layer on ZnO was characterized by optical absorption which depends on the temperature of the measured system, the pentacene film thickness, and the molecular orientation and packing. The high quality of the pentacene films allowed in one case to characterize the Davydov splitting by linear polarized light focused on a single crystallite. Another subject in the field of organic-inorganic hybrid materials comprised conjugated dithiols used as self-assembled monolayers (SAMs) for immobilizing semiconducting CdS nanoparticles (NPs) on Au substrates. It was demonstrated that an appropriate selection and preparation of the conjugated SAMs is crucial for building up a light-addressable potentiometric sensor with a sufficient efficiency. An optimized electron transfer was achieved with SAMs of long range ordering, high stability, and adequate conductivity. This was examined for different linkers and was best for stilbenedithiol immobilized in solution at higher temperatures. Due

  3. A tapered undulator experiment at the ELBE far infrared hybrid-resonator oscillator free electron laser.

    Science.gov (United States)

    Asgekar, V; Lehnert, U; Michel, P

    2012-01-01

    A tapered undulator experiment was carried out at the ELBE far-infrared free electron laser (FEL). The oscillator FEL makes use of a hybrid optical resonator. The main motivation was to see whether the presence of a dispersive medium in the form of a waveguide in the resonator has any effect on the outcome. The FEL saturated power and the wavelength shifts have been measured as a function of both positive as well as negative undulator field amplitude tapering. In contrast to the typical high-gain FELs where positive tapering proves beneficial for the output power we observed an improvement of performance at negative taper. During the same experiments we studied the characteristics of the detuning curves. The width of the curves indicates a maximum small signal gain for zero taper while the output peak power increases with negative taper. The saturated power output, the detuning curve characteristics, and the wavelength shifts agrees with the theoretical predictions. Details of the experiment are presented.

  4. Characterization by fluorescence and electron microscopy in situ hybridization of a double Y isochromosome

    Energy Technology Data Exchange (ETDEWEB)

    Fetni, R.; Lemieux, N.; Richer, C.L. [Universite de Montreal, Quebec (Canada)] [and others

    1996-06-14

    A patient with mixed gonadal dysgenesis and Y isochromosomes I(Y) is described. Lymphocyte cultures from peripheral blood contained a high proportion of 45,X cells and several other cell lines with two different marker chromosomes (mars). These markers had either a monocentric (mar1) or a dicentric appearance (mar2). Following high-resolution GTG, RBG, QFQ, and CBG bandings, five cell lines were identified; 45,X/46,X, + mar1/46,X, + mar2/47,X, + mar1x2/47,X + mar2x2. The percentages were 66/6/26/1/1%, respectively. Chromosome banding analyses were insufficient for characterization of the markers. In situ hybridization of specific probes for the Y centromere and its short arm showed, both in fluorescence and electron microscopy (ENT), two different Y rearrangements. Mar1 is an isochromosome for the short arm i(Yp) and mar2 is a dicentric which was shown by EM to be a double isochromosome Yp, inv dup i(Yp). The breakpoint producing mar1 is within the centromere and the one producing mar2 is within one of the short arms of the Y isochromosome. The findings of different cell populations in peripheral blood lymphocytes indicate the postzygotic instability of this i(Yp). 24 refs., 3 figs., 1 tab.

  5. Hybrid zone origins, species boundaries, and the evolution of wing-pattern diversity in a polytypic species complex of North American admiral butterflies (Nymphalidae: Limenitis).

    Science.gov (United States)

    Mullen, Sean P; Dopman, Erik B; Harrison, Richard G

    2008-06-01

    Hybrid zones present opportunities to study the effects of gene flow, selection, and recombination in natural populations and, thus, provide insights into the genetic and phenotypic changes that occur early in speciation. Here we investigate a hybrid zone between mimetic (Limenitis arthemis astyanax) and nonmimetic (Limenitis arthemis arthemis) populations of admiral butterflies using DNA sequence variation from mtDNA and seven nuclear gene loci. We find three distinct mitochondrial clades within this complex, and observe a strong overall concordance between wing-pattern phenotypes and mitochondrial variation. Nuclear gene genealogies, in contrast, revealed no evidence of exclusivity for either wing-pattern phenotype, suggesting incomplete barriers to gene exchange and/or insufficient time for lineage sorting. Coalescent simulations indicate that gene flow between these two subspecies is highly asymmetric, with the majority of migration occurring from mimetic into nonmimetic populations. Selective sweeps of alleles responsible for mimetic phenotypes may have occurred more than once when mimetic and nonmimetic Limenitis occurred together in the presence of the model (Battus philenor).

  6. Electron field emission characteristics of graphene/carbon nanotubes hybrid field emitter

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Leifeng, E-mail: chlf@hdu.edu.cn [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); He, Hong; Yu, Hua; Cao, Yiqi [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Lei, Da, E-mail: leida126@126.com [Ordos College of Inner Mongolia University, Inner Mongolia University, Ordos 017000 (China); Menggen, QiQiGe [Ordos College of Inner Mongolia University, Inner Mongolia University, Ordos 017000 (China); Wu, Chaoxing; Hu, Liqin [College of Physics and Information Engineering, Fuzhou University, Fuzhou 350002 (China)

    2014-10-15

    The graphene (GP) and multi-walled carbon nanotubes (MCNTs) hybrid nanostructure emitter was constructed by a larger scale electrophoretic deposition (EPD) method. The field emission (FE) performance of the hybrid emitter is greatly improved compared with that of only GP or MCNTs emitter. The low turn-on electric field (EF), the low threshold EF and the reliability FE properties are obtained from the hybrid emitter. The better FE properties result from the improved electrical properties. For further enhancement FE of hybrids, Ag Nanoparticles (NPs) were decorated on the hybrids and FE characteristics were also studied. These studies indicate that we can use the hybrid nanostructure to improve conductivity and contact resistance, which results in enhancement of the FE properties.

  7. First Principles Study on the Electronic Structure and Interface Stability of Hybrid Silicene/Fluorosilicene Nanoribbons

    National Research Council Canada - National Science Library

    Jiang, Q G; Zhang, J F; Ao, Z M; Wu, Y P

    2015-01-01

    The interface stability of hybrid silicene/fluorosilicene nanoribbons (SFNRs) has been investigated by using density functional theory calculations, where fluorosilicene is the fully fluorinated silicene...

  8. The high Andes, gene flow and a stable hybrid zone shape the genetic structure of a wide-ranging South American parrot

    Directory of Open Access Journals (Sweden)

    Schaefer H Martin

    2011-06-01

    Full Text Available Abstract Background While the gene flow in some organisms is strongly affected by physical barriers and geographical distance, other highly mobile species are able to overcome such constraints. In southern South America, the Andes (here up to 6,900 m may constitute a formidable barrier to dispersal. In addition, this region was affected by cycles of intercalating arid/moist periods during the Upper/Late Pleistocene and Holocene. These factors may have been crucial in driving the phylogeographic structure of the vertebrate fauna of the region. Here we test these hypotheses in the burrowing parrot Cyanoliseus patagonus (Aves, Psittaciformes across its wide distributional range in Chile and Argentina. Results Our data show a Chilean origin for this species, with a single migration event across the Andes during the Upper/Late Pleistocene, which gave rise to all extant Argentinean mitochondrial lineages. Analyses suggest a complex population structure for burrowing parrots in Argentina, which includes a hybrid zone that has remained stable for several thousand years. Within this zone, introgression by expanding haplotypes has resulted in the evolution of an intermediate phenotype. Multivariate regressions show that present day climatic variables have a strong influence on the distribution of genetic heterogeneity, accounting for almost half of the variation in the data. Conclusions Here we show how huge barriers like the Andes and the regional environmental conditions imposed constraints on the ability of a parrot species to colonise new habitats, affecting the way in which populations diverged and thus, genetic structure. When contact between divergent populations was re-established, a stable hybrid zone was formed, functioning as a channel for genetic exchange between populations.

  9. Method to map one-dimensional electronic wave function by using multiple Brillouin zone angle resolved photoemission

    Directory of Open Access Journals (Sweden)

    Dong-Wook Lee

    2010-10-01

    Full Text Available Angle resolved photoemission spectroscopy (ARPES is a powerful tool to investigate electronic structures in solids and has been widely used in studying various materials. The electronic structure information by ARPES is obtained in the momentum space. However, in the case of one-dimensional system, we here show that we extract the real space information from ARPES data taken over multiple Brillouin zones (BZs. Intensities in the multiple BZs are proportional to the photoemission matrix element which contains information on the coefficient of the Bloch wave function. It is shown that the Bloch wave function coefficients can be extracted from ARPES data, which allows us to construct the real space wave function. As a test, we use ARPES data from proto-typical one-dimensional system SrCuO2 and construct the real space wave function.

  10. Highly efficient hybrid photovoltaics based on hyperbranched three-dimensional TiO2 electron transporting materials

    KAUST Repository

    Mahmood, Khalid

    2015-03-23

    A 3D hyperbranched TiO2 electron transporting material is demonstrated, which exhibits superior carrier transport and lifetime, as well as excellent infiltration, leading to highly efficient mesostructured hybrid solar cells, such as lead-halide perovskites (15.5%) and dye-sensitized solar cells (11.2%). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Electron-transporting small molecule/ o-xylene hybrid additives to boost the performance of simplified inverted polymer solar cells

    Science.gov (United States)

    Qin, Dashan; Cao, Huan; Zhang, Jidong

    2017-05-01

    Electron-transporting small molecule bathophenanthroline (Bphen) together with o-xylene has been used as hybrid additives to improve the performance of simplified inverted polymer solar cells employing ITO alone as cathode and photoactive layer based on polymer [[2,6'-4,8-di(5-ethylhexylthienyl)benzo[1,2-b;3,3-b] dithiophene] [3-fluoro-2[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl

  12. Extracted Venom and Cuticular Compounds of Imported Fire Ants, Solenopsis spp., and Chemotaxonomic Applications Across a Persistent Hybrid Zone

    Science.gov (United States)

    Characterization of cuticular biomolecular assemblages for imported fire ants permit basic distinctions among colonies of S. invicta, S. richteri, and their hybrids; thus, providing opportunities to investigate details of landscape ecology for this species complex as well as to assess levels of inva...

  13. Long-Range Interfacial Electrochemical Electron Transfer of Pseudomonas aeruginosa Azurin-Gold Nanoparticle Hybrid Systems

    DEFF Research Database (Denmark)

    Jensen, Palle Skovhus; Chi, Qijin; Zhang, Jingdong

    2009-01-01

    We have prepared a "hybrid" of the blue copper protein azurin (Pseudomonas aeruginosa) and a 3 nm gold nanoparticle (AuNP). The AuNP/azurin hybrid was assembled on a Au(111)-electrode surface in a two-step process. The AuNP was first attached to the Au(111) electrode via Au-S chemisorption of a 4...

  14. Hybrid (particle in cell-fluid) simulation of ion-acoustic soliton generation including super-thermal and trapped electrons

    Energy Technology Data Exchange (ETDEWEB)

    Nopoush, M.; Abbasi, H. [Faculty of Physics, Amirkabir University of Technology, P. O. Box 15875-4413, Tehran (Iran, Islamic Republic of)

    2011-08-15

    The present paper is devoted to the simulation of the nonlinear disintegration of a localized perturbation into an ion-acoustic soliton in a plasma. Recently, this problem was studied by a simple model [H. Abbasi et al., Plasma Phys. Controlled Fusion 50, 095007 (2008)]. The main assumptions were (i) in the electron velocity distribution function (DF), the ion-acoustic soliton velocity was neglected in comparison to the electron thermal velocity, (ii) on the ion-acoustic evolution time-scale, the electron velocity DF was assumed to be stationary, and (iii) the calculation was restricted to the small amplitude case. In order to generalize the model, one has to consider the evolution of the electron velocity DF for finite amplitudes. For this purpose, a one dimensional electrostatic hybrid code, particle in cell (PIC)-fluid, was designed. It simulates the electrons dynamics by the PIC method and the cold ions dynamics by the fluid equations. The plasma contains a population of super-thermal electrons and, therefore, a Lorentzian (kappa) velocity DF is used to model the high energy tail in the electron velocity DF. Electron trapping is included in the simulation in view of their nonlinear resonant interaction with the localized perturbation. A Gaussian initial perturbation is used to model the localized perturbation. The influence of both the trapped and the super-thermal electrons on this process is studied and compared with the previous model.

  15. Genetic population structure of turbot ( Scophthalmus maximus L.) supports the presence of multiple hybrid zones for marine fishes in the transition zone between the Baltic Sea and the North Sea

    DEFF Research Database (Denmark)

    Eg Nielsen, Einar; Nielsen, P.H.; Meldrup, Dorte

    2004-01-01

    Genetic population structure of turbot (Scophthalmus maximus L.) in the Northeast Atlantic was investigated using eight highly variable microsatellite loci. In total 706 individuals from eight locations with temporal replicates were assayed, covering an area from the French Bay of Biscay...... Sea, suggesting high gene flow among populations in these areas. In contrast, there was a sharp cline in genetic differentiation going from the low saline Baltic Sea to the high saline North Sea. The data were explained best by two divergent populations connected by a hybrid zone; however......, a mechanical mixing model could not be ruled out. A significant part of the genetic variance could be ascribed to variation among years within locality. Nevertheless, the population structure was relatively stable over time, suggesting that the observed pattern of genetic differentiation is biologically...

  16. Resonant Scattering of Relativistic Outer Zone Electrons by Plasmaspheric Plume Electromagnetic Ion Cyclotron Waves

    Institute of Scientific and Technical Information of China (English)

    SU Zhen-Peng; ZHENG Hui-Nan

    2009-01-01

    The bounce-averaged Fokker-Planck equation is solved to study the relativistic electron phase space density(PSD)evolution in the outer radiation belt due to resonant interactions with plasmaspheric plume electromagnetic ion cyclotron(EMIC)waves.It is found that the PSDs of relativistic electrons can be depleted by 1-3 orders of magnitude in 5h,supporting the previous finding that resonant interactions with EMIC waves may account for the frequently observed relativistic electron flux dropouts in the outer radiation belt during the main phase of a storm.The significant precipitation Joss of ~Me V electrons is primarily induced by the EMIC waves in H~+ and He~+ bands.The rapid remove of highly relativistic electrons(>5 MeV)is mainly driven by the EMIC waves in O~+ band at lower pitch-angles,as well as the EMIC waves in H~+ and He~+ bands at larger pitch-angles.Moreover,a stronger depletion of relativistic electrons is found to occur over a wider pitch angle range when EMIC waves are centering relatively higher in the band.

  17. Electron energy distribution functions and negative ion concentrations in tandem and hybrid multicusp negative hydrogen ion sources

    Energy Technology Data Exchange (ETDEWEB)

    Hopkins, M.B. (Dublin City Univ. (Ireland). Dept. of Physics); Bacal, M. (Ecole Polytechnique, 91 - Palaiseau (France). Lab. de Physique des Milieux Ionises); Graham, W.G. (Queen' s Univ., Belfast, Northern Ireland (UK). School of Mathematics and Physics)

    1991-03-14

    The second derivative of a Langmuir probe characteristic is used to establish the electron energy distribution function (EEDF) in both a tandem and hybrid multicusp H{sup -} ion source. Moveable probes are used to establish the spatial variation of the EEDF. The negative ion density is measured by laser induced photo-detachment. In the case of the hybrid source the EEDF consists of a cold Maxwellian in the central region of the source; the electron temperature increases with increasing discharge current (rising from 0.3 eV at 1 A to 1.2 eV at 50 A when the pressure is 0.4 Pa). A hot electron tail exists in the EEDF of the driver region adjacent to each filament which is shown to consist of a distinct group of primary electrons at low pressure (0.08 Pa) but becomes degraded mainly through inelastic collisions at higher pressures (0.27 Pa). The tandem source, on the other hand, has a single driver region which extends throughout the central region. The primary electron confinement times are much longer so that even at the lowest pressure considered (0.07 Pa) the primaries are degraded. In both cases the measured EEDF at specific locations and values of discharge operating parameters are used to establish the rate coefficients for the processes of importance in H{sup -} production and destruction. (author).

  18. Tomography of the fast electron Bremsstrahlung emission during lower hybrid current drive on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Peysson, Y.; Imbeaux, F. [Association Euratom-CEA, CEA/Cadarache, Dept. de Recherches sur la Fusion Controlee (DRFC), 13 - Saint-Paul-lez-Durance (France)

    1999-04-01

    A new tomography dedicated to detailed studies of the fast electron Bremsstrahlung emission in the hard X-ray (HXR) energy range between 20 and 200 keV during lower hybrid (LH) current drive experiments on the TORE SUPRA tokamak [Equipe TORE SUPRA, in Proceedings of the 15. Conference on Plasma Physics and Controlled Nuclear Fusion Research, Seville (International Atomic Energy Agency, Vienna, 1995), 1, AIEA-CN-60 / A1-5, p. 105] is presented. Radiation detection is performed by cadmium telluride(CdTe) semiconductors, which have most of the desirable features for a powerful diagnosing of magnetically confined hot plasmas - compact size, high X-ray stopping efficiency, fast timing characteristics, good energy resolution, no sensitivity to magnetic field, reasonable susceptibility to performance degradation from neutron/{gamma}-induced damages. This instrument is made of two independent cameras viewing a poloidal cross-section of the plasma, with respectively 21 and 38 detectors. A coarse spectrometry - 8 energy channels - is carried out for each chord, with an energy resolution of 20 keV. The spatial resolution in the core of the plasma is 4-5 cm, while the time sampling may be lowered down to of 2-4 ms. Powerful inversion techniques based on maximum entropy or regularization algorithms take fully advantage of the large number of line-integrated measurements for very robust estimates of the local HXR profiles as a function of time and photon energy. A detailed account of main characteristics and performances of the diagnostic is reported as well as preliminary results on LH current drive experiments. (authors)

  19. Nature of electron correlation and hybridization in NixCu1−xMnSb Heusler alloys

    Directory of Open Access Journals (Sweden)

    I. Sarkar

    2016-08-01

    Full Text Available The electronic structure of Heusler alloys having mixed magnetic phases, comprising of vicinal anti-ferromagnetic and ferromagnetic orders, is of great significance. We present the results of an electronic structure study on NixCu1−xMnSb Heusler alloys, using Mn-2p core-level photoemission spectroscopy. Room temperature data in the paramagnetic phase reveal a non-monotonic variation of both electron correlation strength and conduction-band hybridization such that the former enhances while the latter weakens for compositions showing a mixed phase relative to compositions at the phase boundaries to the ordered phases. The results suggest a possible electronic driving force for settling mixed-magnetic phases.

  20. Dynamics of the electron thermal diffusivity at improved energy confinement during lower hybrid plasma heating in the FT-2 tokamak

    Science.gov (United States)

    Kouprienko, D. V.; Altukhov, A. B.; Gurchenko, A. D.; Gusakov, E. Z.; Kantor, M. Yu.; Lashkul, S. I.; Esipov, L. A.

    2010-05-01

    The dynamics of electron heat transport at improved energy confinement during lower hybrid plasma heating in the FT-2 tokamak was studied experimentally. Evolution of the profiles of the electron temperature and density was thoroughly investigated under conditions of fast variation in the plasma parameters. The energy balance in the electron channel is calculated with the help of the ASTRA code by using the measured plasma parameters. Correlation is revealed between the dynamics of electron heat transport and the behavior of small-scale drift turbulence measured using the enhanced scattering correlation diagnostics. The suppression of heat transfer and turbulence agrees well with the increase in the shear of poloidal plasma rotation calculated from experimental data in the neoclassical approximation.

  1. Photovoltaics: Highly Efficient Hybrid Photovoltaics Based on Hyperbranched Three-Dimensional TiO 2 Electron Transporting Materials (Adv. Mater. 18/2015)

    KAUST Repository

    Mahmood, Khalid

    2015-05-01

    Solution-processed hybrid photovoltaics are a potentially disruptive third-generation solar cell technology. On page 2859, A. Amassian and co-workers demonstrate that an electrospun hyperbranched electron-transporting material is capable of achieving highly efficient hybrid solar cells across different platforms, including lead-halide perovskites (15.5%) and dye-sensitized solar cells (11.2%).

  2. Electron dispersion events in the morningside auroral zone and their relationship with VLF emissions

    Energy Technology Data Exchange (ETDEWEB)

    Hardy, D.A.; Burke, W.J. (Hanscom Air Force Base, MA (United States)); Villalon, E. (Northeastern Univ., Boston, MA (United States))

    1990-05-01

    Energy/time dispersion events have been observed in the precipitating electron data in the energy range from 630 eV to 20 keV recorded by the J sensor on the low-altitude, polar-orbiting HILAT satellite. The dispersions are such that the higher-energy electrons are observed earlier in time than the lower-energy electrons The time interval for single dispersion event is from 1 to 2 s. Within an auroral pass in which such energy/time dispersion events are observed, there are typically several such events, and they can be spaced within the pass in either a periodic or aperiodic manner. The events are typically observed within and toward the equatorward edge of the region of diffuse auroral electron precipitation. During a given pass the events can be observed over a wide range of L shells. The occurrence of these events maximizes in the interval 0600-1,200 hours MLT. The energy/time dispersion is generally consistent with the electrons originating from a common source. The events are seen at L shells from 3.7 to greater than 15. The source distance for the electrons is inferred to be generally beyond the equator for events at L shells less than approximately 8 and before the equator for events at higher L shells. Because of the low energies at which the dispersions are observed, it is unlikely that their occurrence can be explained by resonant interaction with VLF waves. Based on circumstantial evidence from other reported observations common to the morning sector, and alternative theoretical explanation is presented. According to this model the dispersion events result from impulsive interactions of the electrons with intense, asymmetric packets of VLF waves via the nonlinear, ponderomotive force.

  3. Redox-active organometallics: magnetic and electronic couplings through carbon-silicon hybrid molecular connectors.

    Science.gov (United States)

    Hamon, Paul; Justaud, Frederic; Cador, Olivier; Hapiot, Philippe; Rigaut, Stéphane; Toupet, Loïc; Ouahab, Lahcène; Stueger, Harald; Hamon, Jean-René; Lapinte, Claude

    2008-12-24

    Treatment of the triflate complex Cp*(dppe)FeOTf [12; Cp* = eta(5)-C(5)(CH(3))(5), dppe = 1,2-bis(diphenylphosphino)ethane, OTf = CF(3)SO(3)] with an excess of HC[triple bond]C-(Si(CH(3))(2))(x)-C[triple bond]CH (x = 2-4) in diethyl ether provides the binuclear bis(vinylidene) derivatives [Cp*(dppe)Fe=C=CH(Si(CH(3))(2))(x)CH=C=Fe(dppe)Cp*][OTf](2) (x = 2, 13; x = 3, 14; x = 4, 15), which were isolated as ochre solids and rapidly characterized by FT-IR, (1)H, (31)P, and (13)C NMR spectroscopies. The complexes 13-15 were reacted with potassium tert-butoxide to afford the bis(alkynediyl) complexes [Cp*(dppe)Fe-C[triple bond]C(Si(CH(3))(2))(x)C[triple bond]C-Fe(dppe)Cp*] (x = 2, 1; x = 3, 2; x = 4, 3), which were isolated as orange powders in yields ranging from 76 to 91%. The IR, cyclic voltammetry, and UV-vis data obtained for 1-3 and the X-ray crystal structures determined for 1 and 3 reveal the importance of the sigma-pi conjugation (hyperconjugation) between the Si-Si sigma bond and the adjacent C[triple bond]C pi-symmetric orbitals in the description of the electronic structure of the ground state of these complexes. When reacted at low temperature with 2 equiv of [(C(5)H(5))(2)Fe]X or AgX [X = BPh(4), B(3,5-(CF(3))(2)C(6)H(3))(4))], compounds 1-3 provide 1[X](2), 2[X](2), and 3[X](2), which can be isolated and stored below -20 degrees C. EPR spectroscopy and magnetization measurements established that the superexchange interaction propagates through the Si-Si bonds (J = -0.97(2) cm(-1) for 3[X](2)). UV-vis-near-IR spectra were obtained with an optically transparent thin-layer electrosynthetic (OTTLE) cell for 1-3[OTf](n) (n = 0-2). A band with a maximum that increases from 6400 cm(-1) (1[OTf]) to 8500 cm(-1) (3[OTf]) observed for the mixed-valence species was ascribed to intervalence charge transfer evidencing photodriven electron transfer through the carbon-silicon hybrid connectors with H(ab) parameters ranging from 64 to 285 cm(-1).

  4. Fabrication and interfacial electronic structure studies on polypyrrole/TiO2 nano hybrid systems for photovoltaic aspects.

    Science.gov (United States)

    Kumar, Ganesan Mohan; Kawakita, Jin; Jayavel, Ramasamy

    2011-05-01

    The progress in studying the interfacial electronic structures of the developing new class of hybrid organic/inorganic material systems have envisaged a new dimension into the field of photovoltaics, which could be of great help in understanding the nature of charge transfer in them. In this regard, electropolymerization of pyrrole monomers have been carried out at room temperature on the surface of TiO2 working electrodes (assisted by UV radiations) and their interfacial electronic structure has been studied as a function of the applied photo anodic potentials. The formation of polypyrrole deposits has been ensured using FT-IR and Raman spectroscopy. Surface analysis of the hybrid matrix revealed the tendency of polymer molecules to cover up the spherical surface of TiO2 nanoparticles that could help in improving the light absorption rate. Signals (bands) corresponding to pyrrole molecules observed in the ultraviolet photoelectron spectroscopy measurements have been correlated with the polaronic states formed and identified to shift as a function of the applied photo anodic potentials, revealing the decrease in work function of the hybrid system to take place (confirmed using cyclic voltammetry measurements). The decreasing trend in the work function elucidates the adjustment in electronic structure of the system (hybrid materials possessing smaller work functions are generally preferred for photovoltaic studies). The aforementioned behavioural aspects have been reasoned with the increase in overpotential values for polarization, from the decrease in up-take rate of the anionic dopant, which increases the current density values, thereby modifying the conductivity of the systems.

  5. Electron-microscopic examination of the transition zone of aluminum-tantalum bimetallic joints (explosion welding)

    Science.gov (United States)

    Volkova, A. Yu.; Greenberg, B. A.; Ivanov, M. A.; Elkina, O. A.; Inozemtsev, A. V.; Plotnikov, A. V.; Patselov, A. M.; Kozhevnikov, V. E.

    2014-04-01

    A study of the structure of an aluminum-tantalum joint and a comparison of this structure with the structures of iron-silver and copper-tantalum joints have revealed the following processes of the interpenetration of the materials that occur during explosion welding: the formation of protrusions, the injection of particles of one material into the other, and the formation of zones of local melting. Regardless of the mutual solubility of the metals being welded, two types of fragmentation occur, i.e., (1) a granulating fragmentation (GF), which includes the formation, explosion-governed (EG) dispersion, and partial consolidation of particles, and (2) the fragmentation that is usually observed during severe plastic deformation. It is important that this traditional fragmentation is not accompanied by the formation and EG dispersion of particles. This feature allows one to easily distinguish these types of fragmentation (traditional and GF fragmentation).

  6. Protonic/electronic hybrid oxide transistor gated by chitosan and its full-swing low voltage inverter applications

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Jin Yu [Shanxi Province Key Laboratory High Gravity Chemical Engineering, North University of China, Taiyuan 030051 (China); Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Zhu, Li Qiang, E-mail: lqzhu@nimte.ac.cn; Xiao, Hui [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Yuan, Zhi Guo, E-mail: ncityzg@163.com [Shanxi Province Key Laboratory High Gravity Chemical Engineering, North University of China, Taiyuan 030051 (China)

    2015-12-21

    Modulation of charge carrier density in condensed materials based on ionic/electronic interaction has attracted much attention. Here, protonic/electronic hybrid indium-zinc-oxide (IZO) transistors gated by chitosan based electrolyte were obtained. The chitosan-based electrolyte illustrates a high proton conductivity and an extremely strong proton gating behavior. The transistor illustrates good electrical performances at a low operating voltage of ∼1.0 V such as on/off ratio of ∼3 × 10{sup 7}, subthreshold swing of ∼65 mV/dec, threshold voltage of ∼0.3 V, and mobility of ∼7 cm{sup 2}/V s. Good positive gate bias stress stabilities are obtained. Furthermore, a low voltage driven resistor-loaded inverter was built by using an IZO transistor in series with a load resistor, exhibiting a linear relationship between the voltage gain and the supplied voltage. The inverter is also used for decreasing noises of input signals. The protonic/electronic hybrid IZO transistors have potential applications in biochemical sensors and portable electronics.

  7. Medium-energy electrons and heavy ions in Jupiter's magnetosphere - Effects of lower hybrid wave-particle interactions

    Science.gov (United States)

    Barbosa, D. D.

    1986-01-01

    A theory of medium-energy (about keV) electrons and heavy ions in Jupiter's magnetosphere is presented. Lower hybrid waves are generated by the combined effects of a ring instability of neutral wind pickup ions and the modified two-stream instability associated with transport of cool Iogenic plasma. The quasi-linear energy diffusion coefficient for lower hybrid wave-particle interactions is evaluated, and several solutions to the diffusion equation are given. Calculations based on measured wave properties show that the noise substantially modifies the particle distribution functions. The effects are to accelerate superthermal ions and electrons to keV energies and to thermalize the pickup ions on time scales comparable to the particle residence time. The S(2+)/S(+) ratio at medium energies is a measure of the relative contribution from Iogenic thermal plasma and neutral wind ions, and this important quantity should be determined from future measurements. The theory also predicts a preferential acceleration of heavy ions with an accleration time that scales inversely with the root of the ion mass. Electrons accelerated by the process contribute to further reionization of the neutral wind by electron impact, thus providing a possible confirmation of Alfven's critical velocity effect in the Jovian magnetosphere.

  8. A wide hybrid zone of chromosome races of the common shrew, Sorex araneus Linnaeus, 1758 (Mammalia, between the Dnieper and Berezina Rivers (Belarus

    Directory of Open Access Journals (Sweden)

    Yu Borisov

    2010-12-01

    Full Text Available Karyological study of 75 specimens of the common shrew, Sorex araneus Linnaeus, 1758, from 8 localities in the Berezina River basin (eastern Belarus was carried out. A wide hybrid zone (not less than 100 km between the northern West Dvina chromosome race (XX / XYY, af, bc, gm, hk, ip, jl, no, qr, tu and the southern Turov race (XX / XYY, af, bc, g, h/k, i, jl, m, n, o, p, q, r, tu was revealed in this region. Frequencies of fused-unfused arms comprising four diagnostic metacentrics of the West Dvina race (g/m, h/k, n/o, q/r were calculated in all capture sites. Taking into consideration the absence of metacentric ip in specimens from six northern localities, the Borisov (Bs race (XX / XYY, af, bc, g/m, h/k, i, jl, n/o, p, q/r, tu (Orlov, Borisov, 2009 was distinguished in these sites. Common shrews from two southern localities on the right and left banks of the Berezina River (Berezino vicinity were referred to the Turov race. The presence of four metacentrics descended from the West Dvina race in the Bs race testifies to the hypothesis expressed earlier that the polymorphic populations of the S. araneus between the Dnieper and Berezina Rivers originated as a result of the West Dvina race spreading from the north and of hybridization between this race and local populations with acrocentric chromosomes.

  9. Effect of primary electron drift on the negative ion efficiency of a volume hybrid multicusp H[sup [minus

    Energy Technology Data Exchange (ETDEWEB)

    Courteille, C.; Bruneteau, J.; Valckx, F.P.G.; Sledziewski, Z.; Bacal, M. (Laboratoire de Physique des Milieux Ionises, Laboratoire du CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France))

    1992-10-05

    A new, large, hybrid volume negative ion source is described. Observations of curvature and [ital grad] [ital B] primary electron drift in the multicusp magnetic field are reported. The direction of the electron drift changes from one filament to the neighboring one, because of the change in the direction of the magnetic field. For a given discharge current the extracted negative ion current and the plasma density at the center of the extraction region are affected by the direction of the primary electron drift of the active filaments. It was shown, however, that the negative ion current is controlled by the plasma density at the center of the extraction region. A trajectory calculation, effected in the guiding center approximation, allows to estimate the average drift velocity.

  10. FEATURES OF THE DEVELOPMENT OF CORN HYBRIDS DEPENDING ON THE TERMS OF PLANTING AND TMTD-PLUS DISINFECTANT IN THE ARID ZONE CENTRAL CISCAUCASIA

    Directory of Open Access Journals (Sweden)

    Kravchenko R. V.

    2015-11-01

    Full Text Available There was given the review of the results of the study in the arid zone of Central Ciscaucasia, the influence of planting terms and presowing seed treatment by the drug called "TMTD-plus", containing the growth stimulator Krezatsin in its composition, on the development of corn hybrids of different maturity groups of the selection of Krasnodar Research Institute of Agriculture named after P.P. Lukyanenko (Ross 199, Ross 299, Krasnodar 382 and Krasnodar 410 and the All-Russian Research Institute of Corn (Mashuk 170, Newton, RIC 345 and Eric, as well as middlematurity population Rossiyskaya 1. The studies were conducted in accordance with the thematic plan of scientific researches of the chair of crop and forage production of the Stavropol State Agrarian University. The soil surface was presented as southern black earth. The technology of growing of maize on the experimental plot corresponds to the standard one for the present area and cultivar. The predecessor is winter wheat. Sowing was performed in three terms. The first (early sowing term was carried out at t = + 7 ... +8 ° C. The second (recommended - when t = + 10 ... + 12 ° C. The third (later sowing time was carried out at t = +15 ° C. The plant density: early-maturing hybrids – 70 thousand pieces/ha, is mid-maturing ones – 60 thousand pieces/ha, middle-ripe – 50 thousand piece/ha, middle-later ones – 45 thousand pieces/ha. The scheme is single-row, with spacing of 70 cm. The application of the studied drug TMTD-plus helped to reduce the growing season of maize plants for one - two days. Thus, changing the sowing terms of maize hybrids and populations, we can largely control the development of plants changing the length of the growing season to two weeks and form a harvesting conveyor, thereby reducing the intensity of field work

  11. Ti/Au Cathode for Electronic transport material-free organic-inorganic hybrid perovskite solar cells

    Science.gov (United States)

    Shi, Tongfei; Chen, Jian; Zheng, Jianqiang; Li, Xinhua; Zhou, Bukang; Cao, Huaxiang; Wang, Yuqi

    2016-12-01

    We have fabricated organic-inorganic hybrid perovskite solar cell that uses a Ti/Au multilayer as cathode and does not use electron transport materials, and achieved the highest power conversion efficiency close to 13% with high reproducibility and hysteresis-free photocurrent curves. Our cell has a Schottky planar heterojunction structure (ITO/PEDOT:PSS/perovskite/Ti/Au), in which the Ti insertion layer isolate the perovskite and Au layers, thus proving good contact between the Au and perovskite and increasing the cells’ shunt resistance greatly. Moreover, the Ti/Au cathode in direct contact with hybrid perovskite showed no reaction for a long-term exposure to the air, and can provide sufficient protection and avoid the perovskite and PEDOT:PSS layers contact with moisture. Hence, the Ti/Au based devices retain about 70% of their original efficiency after 300 h storage in the ambient environment.

  12. A vertebrate reproductive system involving three ploidy levels: hybrid origin of triploids in a contact zone of diploid and tetraploid palearctic green toads (Bufo viridis subgroup).

    Science.gov (United States)

    Stöck, Matthias; Ustinova, Jana; Lamatsch, Dunja K; Schartl, Manfred; Perrin, Nicolas; Moritz, Craig

    2010-04-01

    The rise and consequences of polyploidy in vertebrates, whose origin was associated with genome duplications, may be best studied in natural diploid and polyploid populations. In a diploid/tetraploid (2n/4n) geographic contact zone of Palearctic green toads in northern Kyrgyzstan, we examine 4ns and triploids (3n) of unknown genetic composition and origins. Using mitochondrial and nuclear sequence, and nuclear microsatellite markers in 84 individuals, we show that 4n (Bufo pewzowi) are allopolyploids, with a geographically proximate 2n species (B. turanensis) being their maternal ancestor and their paternal ancestor as yet unidentified. Local 3n forms arise through hybridization. Adult 3n mature males (B. turanensis mtDNA) have 2n mothers and 4n fathers, but seem distinguishable by nuclear profiles from partly aneuploid 3n tadpoles (with B. pewzowi mtDNA). These observations suggest multiple pathways to the formation of triploids in the contact zone, involving both reciprocal origins. To explain the phenomena in the system, we favor a hypothesis where 3n males (with B. turanensis mtDNA) backcross with 4n and 2n females. Together with previous studies of a separately evolved, sexually reproducing 3n lineage, these observations reveal complex reproductive interactions among toads of different ploidy levels and multiple pathways to the evolution of polyploid lineages.

  13. Molecular ecology of the big brown bat (Eptesicus fuscus): Genetic and natural history variation in a hybrid zone

    Science.gov (United States)

    Neubaum, M.A.; Douglas, M.R.; Douglas, M.E.; O'Shea, T.J.

    2007-01-01

    Several geographically distinct mitochondrial DNA (mtDNA) lineages of the big brown bat (Eptesicus fuscus) have been documented in North America. Individuals from 2 of these lineages, an eastern and a western form, co-occur within maternity colonies in Colorado. The discovery of 2 divergent mtDNA lineages in sympatry prompted a set of questions regarding possible biological differences between haplotypes. We captured big brown bats at maternity roosts in Colorado and recorded data on body size, pelage color, litter size, roosting and overwintering behaviors, and local distributions. Wing biopsies were collected for genetic analysis. The ND2 region of the mtDNA molecule was used to determine lineage of the bats. In addition, nuclear DNA (nDNA) intron 1 of the ??-globin gene was used to determine if mtDNA lineages are hybridizing. Eastern and western mtDNA lineages differed by 10.3% sequence divergence and examination of genetic data suggests recent population expansion for both lineages. Differences in distribution occur along the Colorado Front Range, with an increasing proportion of western haplotypes farther south. Results from nDNA analyses demonstrated hybridization between the 2 lineages. Additionally, no outstanding distinctiveness was found between the mtDNA lineages in natural history characters examined. We speculate that historical climate changes separated this species into isolated eastern and western populations, and that secondary contact with subsequent interbreeding was facilitated by European settlement. ?? 2007 American Society of Mammalogists.

  14. Organic-inorganic hybrid lead halide perovskites for optoelectronic and electronic applications.

    Science.gov (United States)

    Zhao, Yixin; Zhu, Kai

    2016-02-07

    Organic and inorganic hybrid perovskites (e.g., CH(3)NH(3)PbI(3)), with advantages of facile processing, tunable bandgaps, and superior charge-transfer properties, have emerged as a new class of revolutionary optoelectronic semiconductors promising for various applications. Perovskite solar cells constructed with a variety of configurations have demonstrated unprecedented progress in efficiency, reaching about 20% from multiple groups after only several years of active research. A key to this success is the development of various solution-synthesis and film-deposition techniques for controlling the morphology and composition of hybrid perovskites. The rapid progress in material synthesis and device fabrication has also promoted the development of other optoelectronic applications including light-emitting diodes, photodetectors, and transistors. Both experimental and theoretical investigations on organic-inorganic hybrid perovskites have enabled some critical fundamental understandings of this material system. Recent studies have also demonstrated progress in addressing the potential stability issue, which has been identified as a main challenge for future research on halide perovskites. Here, we review recent progress on hybrid perovskites including basic chemical and crystal structures, chemical synthesis of bulk/nanocrystals and thin films with their chemical and physical properties, device configurations, operation principles for various optoelectronic applications (with a focus on solar cells), and photophysics of charge-carrier dynamics. We also discuss the importance of further understanding of the fundamental properties of hybrid perovskites, especially those related to chemical and structural stabilities.

  15. Particle Acceleration Zones Above Pulsar Polar Caps Electron and Positron Pair Formation Fronts

    CERN Document Server

    Harding, A K; Harding, Alice K.; Muslimov, Alexander G.

    1998-01-01

    We investigate self-consistent particle acceleration near a pulsar polar cap (PC) by the electrostatic field due to the effect of inertial frame dragging. Test particles gain energy from the electric field parallel to the open magnetic field lines and lose energy by both curvature radiation (CR) and resonant and non-resonant inverse Compton scattering (ICS) with soft thermal X-rays from the neutron star (NS) surface. Gamma-rays radiated by electrons accelerated from the stellar surface produce pairs in the strong magnetic field, which screen the electric field beyond a pair formation front (PFF). Some of the created positrons can be accelerated back toward the surface and produce gamma-rays and pairs that create another PFF above the surface. We find that ICS photons control PFF formation near the surface, but due to the different angles at which the electron and positron scatter the soft photons, positron initiated cascades develop above the surface and screen the accelerating electric field. Stable accelera...

  16. Driving electrocatalytic activity by interface electronic structure control in a metalloprotein hybrid catalyst for efficient hydrogen evolution.

    Science.gov (United States)

    Behera, Sushant Kumar; Deb, Pritam; Ghosh, Arghya

    2016-08-17

    The rational design of metalloprotein hybrid structures and precise calculations for understanding the role of the interfacial electronic structure in regulating the HER activity of water splitting sites and their microscopic effect for obtaining robust hydrogen evolution possess great promise for developing highly efficient nano-bio hybrid HER catalysts. Here, we employ high-accuracy linear-scaling density functional theory calculations using a near-complete basis set and a minimal parameter implicit solvent model within the self-consistent calculations, on silver (Ag) ions assimilated on bacteriorhodopsin (bR) at specific binding sites. Geometry optimization indicates the formation of active sites at the interface of the metalloprotein complex and the density of states reflects the metallic nature of the active sites. The reduced value of the canonical orbital gap indicates the state of dynamic nature after Ag ion assimilation on active sites and smooth electron transfer. These incorporated active protein sites are more efficient in electrolytic splitting of water than pristine sites due to their low value of Gibbs free energy for the HER in terms of hydrogen coverages. Volcano plot analysis and the free energy diagram are compared for understanding the hydrogen evolution efficiency. Moreover, the essential role of the interfacial electronic properties in regulating the HER catalytic activity of water splitting sites and enhancing the efficiency is elucidated.

  17. Applications of the Hybrid Theory to the Scattering of Electrons from HE+ and Li++ and Resonances in these Systems

    Science.gov (United States)

    Bhatia, Anand K.

    2008-01-01

    Applications of the hybrid theory to the scattering of electrons from Ile+ and Li++ and resonances in these systems, A. K. Bhatia, NASA/Goddard Space Flight Center- The Hybrid theory of electron-hydrogen elastic scattering [I] is applied to the S-wave scattering of electrons from He+ and Li++. In this method, both short-range and long-range correlations are included in the Schrodinger equation at the same time. Phase shifts obtained in this calculation have rigorous lower bounds to the exact phase shifts and they are compared with those obtained using the Feshbach projection operator formalism [2], the close-coupling approach [3], and Harris-Nesbet method [4]. The agreement among all the calculations is very good. These systems have doubly-excited or Feshbach resonances embedded in the continuum. The resonance parameters for the lowest ' S resonances in He and Li+ are calculated and they are compared with the results obtained using the Feshbach projection operator formalism [5,6]. It is concluded that accurate resonance parameters can be obtained by the present method, which has the advantage of including corrections due to neighboring resonances and the continuum in which these resonances are embedded.

  18. ORNL TNS program: microwave start-up of tokamak plasmas near electron cyclotron and upper hybrid resonances

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Y. K.M.; Borowski, S. K.

    1977-12-01

    The scenario of toroidal plasma start-up with microwave initiation and heating near the electron cyclotron frequency is suggested and examined here. We assume microwave irradiation from the high field side and an anomalously large absorption of the extraordinary waves near the upper hybrid resonance. The dominant electron energy losses are assumed to be due to magnetic field curvature and parallel drifts, ionization of neutrals, cooling by ions, and radiation by low Z impurities. It is shown by particle and energy balance considerations that electron temperatures around 250 eV and densities of 10/sup 12/ to 10/sup 13/ cm/sup -3/ can be maintained, at least in a narrow region near the upper hybrid resonance, with modest microwave powers in the Impurity Study Experiment (ISX) (120 kW at 28 GHz) and The Next Step (TNS) (0.57 MW at 120 GHz). The loop voltages required for start-up from these initial plasmas are also estimated. It is shown that the loop voltage can be reduced by a factor of five to ten from that for unassisted start-up without an increase in the resistive loss in volt-seconds. If this reduction in loop voltage is verified in the ISX experiments, substantial savings in the cost of power supplies for the ohmic heating (OH) and equilibrium field (EF) coils can be realized in future large tokamaks.

  19. Controlled growth of carbon nanotube-graphene hybrid materials for flexible and transparent conductors and electron field emitters.

    Science.gov (United States)

    Nguyen, Duc Dung; Tai, Nyan-Hwa; Chen, Szu-Ying; Chueh, Yu-Lun

    2012-01-21

    We report a versatile synthetic process based on rapid heating and cooling chemical vapor deposition for the growth of carbon nanotube (CNT)-graphene hybrid materials where the thickness of graphene and density of CNTs are properly controlled. Graphene films are demonstrated as an efficient barrier layer for preventing poisoning of iron nanoparticles, which catalyze the growth of CNTs on copper substrates. Based on this method, the opto-electronic and field emission properties of graphene integrated with CNTs can be remarkably tailored. A graphene film exhibits a sheet resistance of 2.15 kΩ sq(-1) with a transmittance of 85.6% (at 550 nm), while a CNT-graphene hybrid film shows an improved sheet resistance of 420 Ω sq(-1) with an optical transmittance of 72.9%. Moreover, CNT-graphene films are demonstrated as effective electron field emitters with low turn-on and threshold electric fields of 2.9 and 3.3 V μm(-1), respectively. The development of CNT-graphene films with a wide range of tunable properties presented in this study shows promising applications in flexible opto-electronic, energy, and sensor devices.

  20. 3D electrostatic gyrokinetic electron and fully kinetic ion simulation of lower-hybrid drift instability of Harris current sheet

    Science.gov (United States)

    Wang, Zhenyu; Lin, Yu; Wang, Xueyi; Tummel, Kurt; Chen, Liu

    2016-07-01

    The eigenmode stability properties of three-dimensional lower-hybrid-drift-instabilities (LHDI) in a Harris current sheet with a small but finite guide magnetic field have been systematically studied by employing the gyrokinetic electron and fully kinetic ion (GeFi) particle-in-cell (PIC) simulation model with a realistic ion-to-electron mass ratio mi/me . In contrast to the fully kinetic PIC simulation scheme, the fast electron cyclotron motion and plasma oscillations are systematically removed in the GeFi model, and hence one can employ the realistic mi/me . The GeFi simulations are benchmarked against and show excellent agreement with both the fully kinetic PIC simulation and the analytical eigenmode theory. Our studies indicate that, for small wavenumbers, ky, along the current direction, the most unstable eigenmodes are peaked at the location where k →.B → =0 , consistent with previous analytical and simulation studies. Here, B → is the equilibrium magnetic field and k → is the wavevector perpendicular to the nonuniformity direction. As ky increases, however, the most unstable eigenmodes are found to be peaked at k →.B → ≠0 . In addition, the simulation results indicate that varying mi/me , the current sheet width, and the guide magnetic field can affect the stability of LHDI. Simulations with the varying mass ratio confirm the lower hybrid frequency and wave number scalings.

  1. Structural and electronic properties of hybrid perovskites for high-efficiency thin-film photovoltaics from first-principles

    Directory of Open Access Journals (Sweden)

    Federico Brivio

    2013-10-01

    Full Text Available The performance of perovskite solar cells recently exceeded 15% solar-to-electricity conversion efficiency for small-area devices. The fundamental properties of the active absorber layers, hybrid organic-inorganic perovskites formed from mixing metal and organic halides [e.g., (NH4PbI3 and (CH3NH3PbI3], are largely unknown. The materials are semiconductors with direct band gaps at the boundary of the first Brillouin zone. The calculated dielectric constants and band gaps show an orientation dependence, with a low barrier for rotation of the organic cations. Due to the electric dipole of the methylammonium cation, a photoferroic effect may be accessible, which could enhance carrier collection.

  2. Comparison study between coherent echoes at VHF range and electron density estimated by Ionosphere Model for Auroral Zone

    Science.gov (United States)

    Nishiyama, Takanori; Nakamura, Takuji; Tsutsumi, Masaki; Tanaka, Yoshi; Nishimura, Koji; Sato, Kaoru; Tomikawa, Yoshihiro; Kohma, Masashi

    2016-07-01

    Polar Mesosphere Winter Echo (PMWE) is known as back scatter echo from 55 to 85 km in the mesosphere, and it has been observed by MST and IS radar in polar region during non-summer period. Since density of free electrons as scatterer is low in the dark mesosphere during winter, it is suggested that PMWE requires strong ionization of neutral atmosphere associated with Energetic Particles Precipitations (EPPs) during Solar Proton Events [Kirkwood et al., 2002] or during geomagnetically disturbed periods [Nishiyama et al., 2015]. However, studies on relationship between occurrence of PMWE and background electron density has been limited yet [Lübken et al., 2006], partly because the PMWE occurrence rate is known to be quite low (2.9%) [Zeller et al., 2006]. The PANSY (Program of the Antarctic Syowa MST/IS) radar, which is the largest MST radar in Antarctica, observed many PMWE events since it has started mesosphere observations in June 2012. We established an application method of the PANSY radar as riometer, which makes it possible to estimate Cosmic Noise Absorptions (CNA) as proxy of relative variations on background electron density. In addition, electron density profiles from 60 to 150 km altitude are calculated by Ionospheric Model for the Auroral Zone (IMAZ) [McKinnell and Friedrich, 2007] and CNA estimated by the PANSY radar. In this presentation, we would like to focus on strong PMWE during two big geomagnetic storm events, St. Patrick's Day and the Summer Solstice 2015 Event, in order to compare observed PMWE characteristics to model background electron density. On March 19 and 22, recovery phase of St. Patrick's Day Storm, sudden PMWE intensification was detected near 60 km by the PANSY radar. At the same time, strong Cosmic Noise Absorptions (CNA) of 0.8 dB and 1.0 dB were measured, respectively. However, calculated electron density profiles did not show high electron density at the altitude where the PMWE intensification were observed. On June 22, the

  3. Research on modeling of heat source for electron beam welding fusion-solidification zone

    Institute of Scientific and Technical Information of China (English)

    Wang Yajun; Fu Pengfei; Guan Yongjun; Lu Zhijun; Wei Yintao

    2013-01-01

    In this paper,the common heat source model of point and linear heat source in the numerical simulation of electron beam welding (EBW) were summarized and introduced.The combined point-linear heat source model was brought forward and to simulate the welding temperature fields of EBW and predicting the weld shape.The model parameters were put forward and regulated in the combined model,which included the ratio of point heat source to linear heat source Qpr and the distribution of linear heat source Lr.Based on the combined model,the welding temperature fields of EBW were investigated.The results show that the predicted weld shapes are conformable to those of the actual,the temperature fields are reasonable and correct by simulating with combined point-linear heat source model and the typical weld shapes are gained.

  4. Large enhancements in low latitude total electron content during 15 May 2005 geomagnetic storm in Indian zone

    Directory of Open Access Journals (Sweden)

    N. Dashora

    2009-05-01

    Full Text Available Results pertaining to the response of the equatorial and low latitude ionosphere to a major geomagnetic storm that occurred on 15 May 2005 are presented. These results are also the first from the Indian zone in terms of (i GPS derived total electron content (TEC variations following the storm (ii Local low latitude electrodynamics response to penetration of high latitude convection electric field (iii effect of storm induced traveling atmospheric disturbances (TAD's on GPS-TEC in equatorial ionization anomaly (EIA zone.

    Data set comprising of ionospheric TEC obtained from GPS measurements, ionograms from an EIA zone station, New Delhi (Geog. Lat. 28.42° N, Geog. Long. 77.21° E, ground based magnetometers in equatorial and low latitude stations and solar wind data obtained from Advanced Composition Explorer (ACE has been used in the present study. GPS receivers located at Udaipur (Geog. Lat. 24.73° N, Geog. Long. 73.73° E and Hyderabad (Geog. Lat. 17.33° N, Geog. Long. 78.47° E have been used for wider spatial coverage in the Indian zone. Storm induced features in vertical TEC (VTEC have been obtained comparing them with the mean VTEC of quiet days. Variations in solar wind parameters, as obtained from ACE and in the SYM-H index, indicate that the storm commenced on 15 May 2005 at 02:39 UT. The main phase of the storm commenced at 06:00 UT on 15 May with a sudden southward turning of the Z-component of interplanetary magnetic field (IMF-Bz and subsequent decrease in SYM-H index. The dawn-to-dusk convection electric field of high latitude origin penetrated to low and equatorial latitudes simultaneously as corroborated by the magnetometer data from the Indian zone. Subsequent northward turning of the IMF-Bz, and the penetration of the dusk-to-dawn electric field over the dip equator is also discernible. Response of the low latitude ionosphere to this storm may be characterized in terms of (i

  5. Study of the hybrid controller electronics for the nano-stabilization of mechanical vibrations of CLIC quadrupoles

    CERN Document Server

    Fernandez Carmona, P; Collette, C; Esposito, M; Guinchard, M; Janssens, S; Kuzmin, A; Moron Ballester, R

    2011-01-01

    In order to achieve the required levels of luminosity in the CLIC linear collider, mechanical stabilization of quadrupoles to the nanometre level is required. The paper describes a design of hybrid electronics combining an analogue controller and digital communication with the main machine controller. The choice of local analogue control ensures the required low latency while still keeping sufficiently low noise level. Furthermore, it reduces the power consumption, rack space and cost. Sensitivity to radiation single events upsets is reduced compared to a digital controller. The digital part is required for fine tuning and real time monitoring via digitization of critical parameters.

  6. A camera for imaging hard x-rays from suprathermal electrons during lower hybrid current drive on PBX-M

    Energy Technology Data Exchange (ETDEWEB)

    von Goeler, S.; Kaita, R.; Bernabei, S.; Davis, W.; Fishman, H.; Gettelfinger, G.; Ignat, D.; Roney, P.; Stevens, J.; Stodiek, W. (Princeton Univ., NJ (United States). Plasma Physics Lab.); Jones, S.; Paoletti, F. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center); Petravich, G. (Hungarian Academy of Sciences, Budapest (Hungary). Central Research Inst. for Physics); Rimini,

    1993-05-01

    During lower hybrid current drive (LHCD), suprathermal electrons are generated that emit hard X-ray bremsstrahlung. A pinhole camera has been installed on the PBX-M tokamak that records 128 [times] 128 pixel images of the bremsstrahlung with a 3 ms time resolution. This camera has identified hollow radiation profiles on PBX-M, indicating off-axis current drive. The detector is a 9in. dia. intensifier. A detailed account of the construction of the Hard X-ray Camera, its operation, and its performance is given.

  7. Repair boundary for parent tube indications within the upper joint zone of hybrid expansion joint (HEJ) sleeved tubes

    Energy Technology Data Exchange (ETDEWEB)

    Cullen, W.K.; Keating, R.F. [Westinghouse Electric, Pittsburgh, PA (United States)

    1997-02-01

    In the Spring and Fall of 1994, and the Spring of 1995, crack-like indications were found in the upper hybrid expansion joint (HEJ) region of Steam Generator (S/G) tubes which had been sleeved using Westinghouse HEJ sleeves. As a result of these findings, analytic and test evaluations were performed to assess the effect of the degradation on the structural, and leakage, integrity of the sleeve/tube joint relative to the requirements of the United States Nuclear Regulatory Commission`s (NRC) draft Regulatory Guide (RG) 1.121. The results of these evaluations demonstrated that tubes with implied or known crack-like circumferential parent tube indications (PTIs) located 1.1 inches or farther below the bottom of the hardroll upper transition, have sufficient, and significant, integrity relative to the requirements of RG 1.121. Thus, the purpose of this report is to provide background information related to the justification of the modified tube repair boundary.

  8. Ultrafast electron transfer from low band gap conjugated polymer to quantum dots in hybrid photovoltaic materials

    Science.gov (United States)

    Couderc, Elsa; Greaney, Matthew J.; Thornbury, William; Brutchey, Richard L.; Bradforth, Stephen E.

    2014-09-01

    Ultrafast transient absorption spectroscopy is used in conjunction with chemical doping experiments to study the photo-generation of charges in hybrid thin films composed of PCPDTBT and CdSe quantum dots. We show how we use chemical doping experiments to de-convolute the spectral signatures of the transient states in the near infrared.

  9. Understanding the electronic structure of CdSe quantum dot-fullerene (C60) hybrid nanostructure for photovoltaic applications

    Science.gov (United States)

    Sarkar, Sunandan; Rajbanshi, Biplab; Sarkar, Pranab

    2014-09-01

    By using the density-functional tight binding method, we studied the electronic structure of CdSe quantum dot(QD)-buckminsterfullerene (C60) hybrid systems as a function of both the size of the QD and concentration of the fullerene molecule. Our calculation reveals that the lowest unoccupied molecular orbital energy level of the hybrid CdSeQD-C60 systems lies on the fullerene moiety, whereas the highest occupied molecular orbital (HOMO) energy level lies either on the QD or the fullerene depending on size of the CdSe QD. We explored the possibility of engineering the energy level alignment by varying the size of the CdSe QD. With increase in size of the QD, the HOMO level is shifted upward and crosses the HOMO level of the C60-thiol molecule resulting transition from the type-I to type-II band energy alignment. The density of states and charge density plot support these types of band gap engineering of the CdSe-C60 hybrid systems. This type II band alignment indicates the possibility of application of this nanohybrid for photovoltaic purpose.

  10. Efficient Electron Collection in Hybrid Polymer Solar Cells: In-Situ-Generated ZnO/Poly(3-hexylthiophene) Scaffolded by a TiO2 Nanorod Array.

    Science.gov (United States)

    Liao, Wen-Pin; Wu, Jih-Jen

    2013-06-06

    A nanoarchitectural hybrid polymer solar cell, integrating the ordered and the bulk heterojunction hybrid polymer solar cells, is fabricated by infiltrating the diethylzinc/poly(3-hexylthiophene) (P3HT) solution into the interstices of the TiO2 nanorod (NR) array. An inorganic network composed of tiny ZnO nanocrystals is constructed in the in-situ-generated hybrid within the interstice of the single-crystalline TiO2 NRs. The TiO2 NR array, which possesses a longer electron lifetime and an appropriate electron-transport rate, serves not only as an electron transporter/collector extended from fluorine-doped tin oxide (FTO) electrode to sustain the efficient electron collection but also as a scaffold to hold the sufficient amount of ZnO/P3HT hybrid. The in-situ-generated ZnO/P3HT hybrid layer with superior charge separation efficiency can therefore be thickened in the presence of a TiO2 NR array for increasing the light-harvesting efficiency. A notable efficiency of 2.46% is therefore attained in the TiO2 NR-ZnO/P3HT hybrid solar cell.

  11. Screened Hybrid and DFT + U Studies of the Structural, Electronic, and Optical Properties of U3O8

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Xiaodong; Martin, Richard L.; Scuseria, Gustavo E.; Rudin, Sven P.; Batista, Enrique R.; Burrell, Anthony K.

    2012-11-26

    A systematic comparison of the structures and electronic and optical properties of U3O8 in the c2mm, P¯62m, and P21/m structures (the α, β, and γ phases, respectively) is performed using density functional theory + U (PBE + U) and the Heyd–Scuseria–Ernzerhof screened hybrid functional (HSE). The relationship between the semiconducting C2mm phase of U3O8 and the high temperature, metallic P¯62m phase is explored in more detail. Our calculated results show that the HSE functional gives a better description of the electronic and optical properties when compared with available experimental data for the α and β phases, but neither approach does particularly well for the high pressure γ phase.

  12. Screened hybrid and DFT + U studies of the structural, electronic, and optical properties of U3O8

    Science.gov (United States)

    Wen, Xiao-Dong; Martin, Richard L.; Scuseria, Gustavo E.; Rudin, Sven P.; Batista, Enrique R.; Burrell, Anthony K.

    2013-01-01

    A systematic comparison of the structures and electronic and optical properties of U3O8 in the c2mm, P\\bar {6}2 m, and P21/m structures (the α, β, and γ phases, respectively) is performed using density functional theory + U (PBE + U) and the Heyd-Scuseria-Ernzerhof screened hybrid functional (HSE). The relationship between the semiconducting C2mm phase of U3O8 and the high temperature, metallic P\\bar {6}2 m phase is explored in more detail. Our calculated results show that the HSE functional gives a better description of the electronic and optical properties when compared with available experimental data for the α and β phases, but neither approach does particularly well for the high pressure γ phase.

  13. Hybrids of organic molecules and flat, oxide-free silicon: high-density monolayers, electronic properties, and functionalization.

    Science.gov (United States)

    Li, Yan; Calder, Steven; Yaffe, Omer; Cahen, David; Haick, Hossam; Kronik, Leeor; Zuilhof, Han

    2012-07-03

    Since the first report of Si-C bound organic monolayers on oxide-free Si almost two decades ago, a substantial amount of research has focused on studying the fundamental mechanical and electronic properties of these Si/molecule surfaces and interfaces. This feature article covers three closely related topics, including recent advances in achieving high-density organic monolayers (i.e., atomic coverage >55%) on oxide-free Si(111) substrates, an overview of progress in the fundamental understanding of the energetics and electronic properties of hybrid Si/molecule systems, and a brief summary of recent examples of subsequent functionalization on these high-density monolayers, which can significantly expand the range of applicability. Taken together, these topics provide an overview of the present status of this active area of research.

  14. Electronic and optical properties of (U,Th)O2 compound from screened hybrid density functional studies

    Science.gov (United States)

    Mo, Chongjie; Yang, Yu; Kang, Wei; Zhang, Ping

    2016-04-01

    The electronic structure and optical properties for the (U,Th)O2 compound are systematically studied by employing the Heyd-Scuseria-Ernzerh method (HSE) of screened hybrid density functional. The electronic band gap of (U,Th)O2 is predicted to be 3.06 eV, in the middle of the values of UO2 and ThO2. Based on wavefunction analysis, we conclude (U,Th)O2 to be a Mott insulator in its ground state. The frequency dependent dielectric functions and optical properties are then calculated and compared with those of ThO2 and UO2. At the visible light frequency range, the adsorption coefficients for ThO2, UO2 and (U,Th)O2 are totally different, which gives an accessible method to predict the proportion of U atoms in an arbitrary unknown (U,Th)O2 compounds from the adsorption spectrum of visible lights.

  15. Strength Evaluation of Heat Affected Zone in Electron Beam Welded ARAA for HCCR TBM in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, J. S.; Kim, S. K.; Jin, H. G.; Lee, E. H.; Lee, D. W. [KAERI, Daejeon (Korea, Republic of); Cho, S. [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    The Korean helium cooled ceramic reflector (HCCR) test blanket module (TBM) has been developed for ITER, and Korean reduced activation ferritic martensitic (RAFM) steel, called advanced reduced activation alloy (ARAA), has also been developed for a structural material of the HCCR TBM. One case of limited optimized electron beam (EB) welding conditions was selected based on previous work, and the weldability of an EB weld was evaluated for TBM fabrication. The micro-hardness was measured from the base to the weld region, and the microstructures were also observed. A small punch (SP) test considering the HAZ was carried out at room and high (550 .deg. C) temperatures. The empirical mechanical properties of HAZ in the EB weld were evaluated, and the fracture behavior was investigated after the SP test. The SP results show that the estimated yield and tensile strength of the HAZ were higher than the base metal at both temperatures. Korean RAFM steel, ARAA, was developed as a TBM structural material. Using one of the program alloys in ARAA (F206), one case of a limited optimized EB welding condition was selected based on previous works, and the weldability of an EB weld using the SP test was evaluated for TBM fabrication at room and high (550 .deg. C) temperatures. From a micro-Vickers hardness evaluation, the HAZ gave the highest values compared with the other regions. The irregular grain boundaries in the HAZ were observed, but its width was narrower than the TIG weld from the previous results. The optimized welding methods such as the TIG, EB, and laser weld, and the welding procedure considering the PWHT are being established, and the weldability evaluation is also progressing according to the development of the ARAA for the fusion material application in Korea.

  16. Tuning the electronic hybridization in the heavy fermion cage compound YbFe2Zn20 with Cd doping

    Science.gov (United States)

    Cabrera-Baez, M.; Ribeiro, R. A.; Avila, M. A.

    2016-09-01

    The tuning of the electronic properties of heavy fermion compounds by chemical substitution provides excellent opportunities for further understanding the physics of hybridized ions in crystal lattices. Here we present an investigation on the effects of Cd doping in flux-grown single crystals of the complex intermetallic cage compound YbFe2Zn20, which has been described as a heavy fermion with a Sommerfeld coefficient of 535 mJ mol-1 · K-2. The substitution of Cd for Zn disturbs the system by expanding the unit cell and, in this case, the size of the Zn cages that surround the Yb and Fe. With an increasing amount of Cd, the hybridization between the Yb 4f electrons and the conduction electrons is weakened, as shown by a decrease in the Sommerfeld coefficient, which should be accompanied by a valence shift of the Yb3+ due to the negative chemical pressure effect. This scenario is also supported by the low temperature DC magnetic susceptibility, which is gradually suppressed and shows an increment of the Kondo temperature, based on a shift to higher temperatures of the characteristic broad susceptibility peak. Furthermore, the DC resistivity decreases with the isoelectronic substitution of Cd for Zn, contrary to expectations in an increasingly disordered system, and implying that the valence shift is not related to charge carrier doping. The combined results demonstrate the excellent complementarity between positive physical pressure and negative chemical pressure, and point to a rich playground for exploring the physics and chemistry of strongly correlated electron systems in the general family of Zn20 compounds, despite their structural complexity.

  17. An approach to identify putative hybrids in the 'coalescent stochasticity zone', as exemplified in the African plant genus Streptocarpus (Gesneriaceae).

    Science.gov (United States)

    de Villiers, Margaret J; Pirie, Michael D; Hughes, Mark; Möller, Michael; Edwards, Trevor J; Bellstedt, Dirk U

    2013-04-01

    The inference of phylogenetic relationships is often complicated by differing evolutionary histories of independently-inherited markers. The causes of the resulting gene tree incongruence can be challenging to identify, often relying on coalescent simulations dependent on unverifiable assumptions. We investigated alternative techniques using the South African rosulate species of Streptocarpus as a study group. Two independent gene trees - from the nuclear ITS region and from three concatenated plastid regions (trnL-F, rpl20-rps12 and trnC-D) - displayed widespread, strongly supported incongruence. We investigated the causes by detecting genetic exchange across morphological borders using morphological optimizations and genetic exchange across species boundaries using the genealogical sorting index. Incongruence between gene trees was associated with ancestral shifts in growth form (in four species) but not in pollination syndrome, suggesting introgression limited by reproductive barriers. Genealogical sorting index calculations showed polyphyly of two additional species, while individuals of all others were significantly associated. In one case the association was stronger according to the internal transcribed spacer data than according to the plastid data, which, given the smaller effective population size of the plastid, may also indicate introgression. These approaches offer alternative ways to identify potential hybridization events where incomplete lineage sorting cannot be rejected using simulations. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  18. An improved hybrid multi-criteria/multidimensional model for strategic industrial location selection: Casablanca industrial zones as a case study.

    Science.gov (United States)

    Boutkhoum, Omar; Hanine, Mohamed; Agouti, Tarik; Tikniouine, Abdessadek

    2015-01-01

    In this paper, we examine the issue of strategic industrial location selection in uncertain decision making environments for implanting new industrial corporation. In fact, the industrial location issue is typically considered as a crucial factor in business research field which is related to many calculations about natural resources, distributors, suppliers, customers, and most other things. Based on the integration of environmental, economic and social decisive elements of sustainable development, this paper presents a hybrid decision making model combining fuzzy multi-criteria analysis with analytical capabilities that OLAP systems can provide for successful and optimal industrial location selection. The proposed model mainly consists in three stages. In the first stage, a decision-making committee has been established to identify the evaluation criteria impacting the location selection process. In the second stage, we develop fuzzy AHP software based on the extent analysis method to assign the importance weights to the selected criteria, which allows us to model the linguistic vagueness, ambiguity, and incomplete knowledge. In the last stage, OLAP analysis integrated with multi-criteria analysis employs these weighted criteria as inputs to evaluate, rank and select the strategic industrial location for implanting new business corporation in the region of Casablanca, Morocco. Finally, a sensitivity analysis is performed to evaluate the impact of criteria weights and the preferences given by decision makers on the final rankings of strategic industrial locations.

  19. Implications of orbital hybridization on the electronic properties of doped quantum dots: the case of Cu:CdSe

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Joshua T.; Forsythe, Kyle; Hutchins, Jamie; Meulenberg, Robert W.

    2016-04-13

    This paper investigates how chemical dopants affect the electronic properties of CdSe quantum dots (QDs) and why a model that incorporates the concepts of orbital hybridization must be used to understand these properties. Extended X-ray absorption fine structure spectroscopy measurements show that copper dopants in CdSe QDs occur primarily through a statistical doping mechanism. Ultraviolet photoemission spectroscopy (UPS) experiments provide a detailed insight on the valence band (VB) structure of doped and undoped QDs. Using UPS measurements, we are able to observe photoemission from the Cu d-levels above VB maximum of the QDs which allows a complete picture of the energy band landscape of these materials. This information provides insights into many of the physical properties of doped QDs, including the highly debated near-infrared photoluminescence in Cu doped CdSe QDs. We show that all our results point to a common theme of orbital hybridization in Cu doped CdSe QDs which leads to optically and electronically active states below the conduction band minimum. Our model is supported from current–voltage measurements of doped and undoped materials, which exhibit Schottky to Ohmic behavior with Cu doping, suggestive of a tuning of the lowest energy states near the Fermi level.

  20. Design of Passive Analog Electronic Circuits Using Hybrid Modified UMDA algorithm

    Directory of Open Access Journals (Sweden)

    J. Slezak

    2015-04-01

    Full Text Available Hybrid evolutionary passive analog circuits synthesis method based on modified Univariate Marginal Distribution Algorithm (UMDA and a local search algorithm is proposed in the paper. The modification of the UMDA algorithm which allows to specify the maximum number of the nodes and the maximum number of the components of the synthesized circuit is proposed. The proposed hybrid approach efficiently reduces the number of the objective function evaluations. The modified UMDA algorithm is used for synthesis of the topology and the local search algorithm is used for determination of the parameters of the components of the designed circuit. As an example the proposed method is applied to a problem of synthesis of the fractional capacitor circuit.

  1. First Principles Study on the Electronic Structure and Interface Stability of Hybrid Silicene/Fluorosilicene Nanoribbons

    OpenAIRE

    Jiang, Q G; Zhang, J. F.; Ao, Z. M.; Y. P. Wu

    2015-01-01

    The interface stability of hybrid silicene/fluorosilicene nanoribbons (SFNRs) has been investigated by using density functional theory calculations, where fluorosilicene is the fully fluorinated silicene. It is found that the diffusion of F atoms at the zigzag and armchair interfaces of SFNRs is endothermic, and the corresponding minimum energy barriers are respectively 1.66 and 1.56?eV, which are remarkably higher than the minimum diffusion energy barrier of one F atom and two F atoms on pri...

  2. Carbon and metal nanotube hybrid structures on graphene as efficient electron field emitters

    Science.gov (United States)

    Heo, Kwang; Lee, Byung Yang; Lee, Hyungwoo; Cho, Dong-guk; Arif, Muhammad; Kim, Kyu Young; Choi, Young Jin; Hong, Seunghun

    2016-07-01

    We report a facile and efficient method for the fabrication of highly-flexible field emission devices by forming tubular hybrid structures based on carbon nanotubes (CNTs) and nickel nanotubes (Ni NTs) on graphene-based flexible substrates. By employing an infiltration process in anodic alumina oxide (AAO) templates followed by Ni electrodeposition, we could fabricate CNT-wrapped Ni NT/graphene hybrid structures. During the electrodeposition process, the CNTs served as Ni nucleation sites, resulting in a large-area array of high aspect-ratio field emitters composed of CNT-wrapped Ni NT hybrid structures. As a proof of concepts, we demonstrate that high-quality flexible field emission devices can be simply fabricated using our method. Remarkably, our proto-type field emission devices exhibited a current density higher by two orders of magnitude compared to other devices fabricated by previous methods, while maintaining its structural integrity in various bending deformations. This novel fabrication strategy can be utilized in various applications such as optoelectronic devices, sensors and energy storage devices.

  3. Hybrid matrix method for stable numerical analysis of the propagation of Dirac electrons in gapless bilayer graphene superlattices

    Science.gov (United States)

    Briones-Torres, J. A.; Pernas-Salomón, R.; Pérez-Álvarez, R.; Rodríguez-Vargas, I.

    2016-05-01

    Gapless bilayer graphene (GBG), like monolayer graphene, is a material system with unique properties, such as anti-Klein tunneling and intrinsic Fano resonances. These properties rely on the gapless parabolic dispersion relation and the chiral nature of bilayer graphene electrons. In addition, propagating and evanescent electron states coexist inherently in this material, giving rise to these exotic properties. In this sense, bilayer graphene is unique, since in most material systems in which Fano resonance phenomena are manifested an external source that provides extended states is required. However, from a numerical standpoint, the presence of evanescent-divergent states in the eigenfunctions linear superposition representing the Dirac spinors, leads to a numerical degradation (the so called Ωd problem) in the practical applications of the standard Coefficient Transfer Matrix (K) method used to study charge transport properties in Bilayer Graphene based multi-barrier systems. We present here a straightforward procedure based in the hybrid compliance-stiffness matrix method (H) that can overcome this numerical degradation. Our results show that in contrast to standard matrix method, the proposed H method is suitable to study the transmission and transport properties of electrons in GBG superlattice since it remains numerically stable regardless the size of the superlattice and the range of values taken by the input parameters: the energy and angle of the incident electrons, the barrier height and the thickness and number of barriers. We show that the matrix determinant can be used as a test of the numerical accuracy in real calculations.

  4. The problem of the use the hybrid and photovoltaic systems in insular zones with climatic siversity in Madeira; A problematica da utilizacao de sistemas fotovoltaicos e hibridos em zonas insulares de diversidade climatica-ILHA da Madeira

    Energy Technology Data Exchange (ETDEWEB)

    Magro, J. C. E.

    2004-07-01

    Project PAUER contemplates the evaluation and utilization of renewable energy in insular zones with climatic diversity, situated on the Archipelago of Madeira. The project has three main areas of intervention: prospecting and evaluating energetic resources; creation of data bases of climatic data for application in energetic studies and other areas; the installation of twenty autonomous photovoltaic or hybrid systems in isolated localities. This communication presents some data from meteorological observations made up until the present date, following appropriate statistical analysis. Characteristics of some installed photovoltaic and hybrid systems as well as some of the principal problems encountered in the field are also given. (Author)

  5. A hybrid machine learning model to estimate nitrate contamination of production zone groundwater in the Central Valley, California

    Science.gov (United States)

    Ransom, K.; Nolan, B. T.; Faunt, C. C.; Bell, A.; Gronberg, J.; Traum, J.; Wheeler, D. C.; Rosecrans, C.; Belitz, K.; Eberts, S.; Harter, T.

    2016-12-01

    A hybrid, non-linear, machine learning statistical model was developed within a statistical learning framework to predict nitrate contamination of groundwater to depths of approximately 500 m below ground surface in the Central Valley, California. A database of 213 predictor variables representing well characteristics, historical and current field and county scale nitrogen mass balance, historical and current landuse, oxidation/reduction conditions, groundwater flow, climate, soil characteristics, depth to groundwater, and groundwater age were assigned to over 6,000 private supply and public supply wells measured previously for nitrate and located throughout the study area. The machine learning method, gradient boosting machine (GBM) was used to screen predictor variables and rank them in order of importance in relation to the groundwater nitrate measurements. The top five most important predictor variables included oxidation/reduction characteristics, historical field scale nitrogen mass balance, climate, and depth to 60 year old water. Twenty-two variables were selected for the final model and final model errors for log-transformed hold-out data were R squared of 0.45 and root mean square error (RMSE) of 1.124. Modeled mean groundwater age was tested separately for error improvement in the model and when included decreased model RMSE by 0.5% compared to the same model without age and by 0.20% compared to the model with all 213 variables. 1D and 2D partial plots were examined to determine how variables behave individually and interact in the model. Some variables behaved as expected: log nitrate decreased with increasing probability of anoxic conditions and depth to 60 year old water, generally decreased with increasing natural landuse surrounding wells and increasing mean groundwater age, generally increased with increased minimum depth to high water table and with increased base flow index value. Other variables exhibited much more erratic or noisy behavior in

  6. Hybrid Simulation of Laser-Plasma Interactions and Fast Electron Transport in Inhomogeneous Plasma

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, B I; Kemp, A; Divol, L

    2009-05-27

    A new framework is introduced for kinetic simulation of laser-plasma interactions in an inhomogenous plasma motivated by the goal of performing integrated kinetic simulations of fast-ignition laser fusion. The algorithm addresses the propagation and absorption of an intense electromagnetic wave in an ionized plasma leading to the generation and transport of an energetic electron component. The energetic electrons propagate farther into the plasma to much higher densities where Coulomb collisions become important. The high-density plasma supports an energetic electron current, return currents, self-consistent electric fields associated with maintaining quasi-neutrality, and self-consistent magnetic fields due to the currents. Collisions of the electrons and ions are calculated accurately to track the energetic electrons and model their interactions with the background plasma. Up to a density well above critical density, where the laser electromagnetic field is evanescent, Maxwell's equations are solved with a conventional particle-based, finite-difference scheme. In the higher-density plasma, Maxwell's equations are solved using an Ohm's law neglecting the inertia of the background electrons with the option of omitting the displacement current in Ampere's law. Particle equations of motion with binary collisions are solved for all electrons and ions throughout the system using weighted particles to resolve the density gradient efficiently. The algorithm is analyzed and demonstrated in simulation examples. The simulation scheme introduced here achieves significantly improved efficiencies.

  7. Electronic Interfacing Between a Living Cell and a Nanodevice: A Bio-Nano Hybrid System

    Energy Technology Data Exchange (ETDEWEB)

    Saraf, Ravi F. [Univ. of Nebraska, Lincoln, NE (United States). Dept. of Chemical and Biomolecular Engineering

    2013-12-31

    The primary goal of this program was to couple physical electronics with live cells to leverage the highly sophisticated functions of a biological system to ultimately create advanced functionality. The study was built on a unique self-assembled architecture of nanoparticles that exhibits transport properties that are sensitive to single-electron charge modulation. At room temperature, the energy of switching due to single-electron charge modulation was in the range of 4 to 100 kT. The structure invented in the principal investigator’s lab is a two-dimensional (2D) network of one-dimensional (1D) necklaces of 10 nm Au nanoparticles. The electron transport through the necklace network is regulated by quantum mechanical single-electron traps. As a result of the single electron traps, the all metal nanoparticle network array displays a conduction band gap. Fundamental studies on the transport properties of the network in air and water were studied to regulate the band gap by tailoring the network structure to demonstrate the first electrochemical single electron transistor operating in water. Cells were interfaced with the network to observe electrochemical activity in a cell during photosynthesis and single viral infection.

  8. Effects of APTEOS content and electron beam irradiation on physical and separation properties of hybrid nylon-66 membranes

    Energy Technology Data Exchange (ETDEWEB)

    Linggawati, A. [Department of Chemical and Process Engineering, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Mohammad, A.W., E-mail: wahabm@eng.ukm.my [Department of Chemical and Process Engineering, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Leo, C.P. [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, S.P.S., Penang (Malaysia)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Hybrid nylon-66 membranes were prepared using APTEOS and modified by EB irradiation. Black-Right-Pointing-Pointer APTEOS increase the formation of cellular pores. Black-Right-Pointing-Pointer EB irradiation causes the growth of dense layer. Black-Right-Pointing-Pointer 10 wt% of APTEOS and irradiation at 70 kGy shows satisfactory separation of salt. - Abstract: Nylon-66 contains functional groups which form hydrogen bonds with inorganic silica networks and allow the creation of hybrid membranes. As a typical semicrystalline polymer, nylon-66 can be crosslinked through electron beam (EB) irradiation to form nanofiltration membranes. The effects of {gamma}-aminopropyltriethoxylsilane (APTEOS) and EB irradiation on the physical and separation properties of nylon-66 membranes were studied in this work. Hybrid nylon-66 membranes were prepared by adding an APTEOS solution (5 wt%, 10 wt% and 20 wt%) into nylon-66 which was dissolved in formic acid. Before air drying, membranes were irradiated at 60 kGy, 70 kGy and 80 kGy. More cellular pores were formed in nylon-66 membranes with the addition of APTEOS. However, increased irradiation dose caused the formation of a dense layer in nylon-66 membranes. Crosslinked silica in nylon-66 membranes was confirmed by FT-IR and DMA, while XRD results showed that there was a high degree of crystallinity in some membranes after irradiation. With improvements in membrane pore size and the ratio of membrane thickness to porosity, nylon-66 membrane with 10 wt% of APTEOS irradiated at 70 kGy exhibited satisfactory permeability, excellent removal of neutral solutes and improved rejection of divalent ions.

  9. Analysis of Schwalbe′s Line (Limbal Smooth Zone by Scanning Electron Microscopy and Optical Coherence Tomography in Human Eye Bank Eyes

    Directory of Open Access Journals (Sweden)

    Mark P Breazzano

    2013-01-01

    Full Text Available Purpose: Implantation of intraocular devices may become critical as they decrease in size in the future. Therefore, it is desirable to evaluate the relationship between radial location and Schwalbe′s line (smooth zone by examining its width with scanning electron microscopy (SEM and to correlate this with observations by optical coherence tomography (OCT. Methods: Full corneoscleral rings were obtained from twenty-six formalin-fixed human phakic donor eyes. SEM of each eye yielded a complete montage of the smooth zone, from which the area was measured, and width was determined in each quadrant. In three different eyes, time domain anterior segment OCT (Visante, Carl Zeiss Meditec Inc., Dublin, CA, USA and spectral domain OCT (Cirrus 4.0, Carl Zeiss Meditec Inc., Dublin, CA, USA were used to further characterize Schwalbe′s line. Results: The overall smooth zone width was 79±22 μm, (n=15 ranging from 43 to 115 μm. The superior quadrant (103±8 μm, n=19, demonstrated significantly wider smooth zone than both the nasal (71±5 μm, n=19, P0.05. SEM findings of the smooth zone were correlated with visualization of Schwalbe′s line by Cirrus and Visante OCT imaging. Conclusion: The smooth zone appears widest superiorly and thinnest inferonasally, suggesting that as glaucoma surgical devices become smaller, their placement could be targeted clinically by using OCT with preference to the superior quadrant, to minimize damage to the corneal endothelium.

  10. Conducting polymer-coated Physarum polycephalum towards the synthesis of bio-hybrid electronic devices

    Science.gov (United States)

    de Lacy Costello, B. J. P.; Mayne, R.; Adamatzky, A.

    2015-04-01

    This paper presents a generic method for the production of functionalized coatings on biological substrates. The specific method described involves the functionalization of the living plasmodial stage of Physarum polycephalum with the conducting organic polymer polypyrrole. The simple method involves localized treatment of tube sections with a solution of ferric chloride, followed by exposure to the vapour or a liquid solution of the pyrrole monomer. This technique enables the production of surface-coated conducting plasmodial tubes of certain lengths to be formed at specific points. Measurement of the electrical resistance of a 1 cm functionalized tube gave a value of 100 k? . The use of this selective functionalization technique means that the majority of the growing plasmodium remains unfunctionalized and living; thus, a true hybrid device is formed. It can be seen how a range of functionalized polymers and materials whereby a chemical activator, for the formation of the product (or the pre-cursor) can be added to P. polycephalum (or other organisms) followed by reaction to form a hybrid material.

  11. Electronic structure modeling of InAs/GaSb superlattices with hybrid density functional theory

    Science.gov (United States)

    Garwood, T.; Modine, N. A.; Krishna, S.

    2017-03-01

    The application of first-principles calculations holds promise for greatly improving our understanding of semiconductor superlattices. Developing a procedure to accurately predict band gaps using hybrid density functional theory lays the groundwork for future studies investigating more nuanced properties of these structures. Our approach allows a priori prediction of the properties of SLS structures using only the band gaps of the constituent materials. Furthermore, it should enable direct investigation of the effects of interface structure, e.g., intermixing or ordering at the interface, on SLS properties. In this paper, we present band gap data for various InAs/GaSb type-II superlattice structures calculated using the generalized Kohn-Sham formulation of density functional theory. A PBE0-type hybrid functional was used, and the portion of the exact exchange was tuned to fit the band gaps of the binary compounds InAs and GaSb with the best agreement to bulk experimental values obtained with 18% of the exact exchange. The heterostructures considered in this study are 6 monolayer (ML) InAs/6 ML GaSb, 8 ML InAs/8 ML GaSb and 10 ML InAs/10 ML GaSb with deviations from the experimental band gaps ranging from 3% to 11%.

  12. Hybrid Orbital and Numerical Grid Representationfor Electronic Continuum Processes: Double Photoionization of Atomic Beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Yip, Frank L; McCurdy, C. William; Rescigno, Thomas N

    2010-04-19

    A general approach for ab initio calculations of electronic continuum processes is described in which the many-electron wave function is expanded using a combination of orbitals at short range and the finite-element discrete variable representation(FEM-DVR) at larger distances. The orbital portion of the basis allows the efficient construction of many-electron configurations in which some of the electrons are bound, but because the orbitals are constructed from an underlying FEM-DVR grid, the calculation of two-electron integrals retains the efficiency of the primitive FEM-DVR approach. As an example, double photoionization of beryllium is treated in a calculation in which the 1s{sup 2} core is frozen. This approach extends the use of exterior complex scaling (ECS) successfully applied to helium and H{sub 2} to calculations with two active electrons on more complicated targets. Integrated, energy-differential and triply-differential cross sections are exhibited, and the results agree well with other theoretical investigations.

  13. An enhanced security solution for electronic medical records based on AES hybrid technique with SOAP/XML and SHA-1.

    Science.gov (United States)

    Kiah, M L Mat; Nabi, Mohamed S; Zaidan, B B; Zaidan, A A

    2013-10-01

    This study aims to provide security solutions for implementing electronic medical records (EMRs). E-Health organizations could utilize the proposed method and implement recommended solutions in medical/health systems. Majority of the required security features of EMRs were noted. The methods used were tested against each of these security features. In implementing the system, the combination that satisfied all of the security features of EMRs was selected. Secure implementation and management of EMRs facilitate the safeguarding of the confidentiality, integrity, and availability of e-health organization systems. Health practitioners, patients, and visitors can use the information system facilities safely and with confidence anytime and anywhere. After critically reviewing security and data transmission methods, a new hybrid method was proposed to be implemented on EMR systems. This method will enhance the robustness, security, and integration of EMR systems. The hybrid of simple object access protocol/extensible markup language (XML) with advanced encryption standard and secure hash algorithm version 1 has achieved the security requirements of an EMR system with the capability of integrating with other systems through the design of XML messages.

  14. Calculation of two-centre two-electron integrals over Slater-type orbitals revisited. I. Coulomb and hybrid integrals

    CERN Document Server

    Lesiuk, Michał

    2014-01-01

    In this paper, which constitutes the first part of the series, we consider calculation of two-centre Coulomb and hybrid integrals over Slater-type orbitals (STOs). General formulae for these integrals are derived with no restrictions on the values of the quantum numbers and nonlinear parameters. Direct integration over the coordinates of one of the electrons leaves us with the set of overlap-like integrals which are evaluated by using two distinct methods. The first one is based on the transformation to the ellipsoidal coordinates system and the second utilises a recursive scheme for consecutive increase of the angular momenta in the integrand. In both methods simple one-dimensional numerical integrations are used in order to avoid severe digital erosion connected with the straightforward use of the alternative analytical formulae. It is discussed that the numerical integration does not introduce a large computational overhead since the integrands are well-behaved functions, calculated recursively with decent...

  15. Femtosecond timing-jitter between photo-cathode laser and ultra-short electron bunches by means of hybrid compression

    Science.gov (United States)

    Pompili, R.; Anania, M. P.; Bellaveglia, M.; Biagioni, A.; Castorina, G.; Chiadroni, E.; Cianchi, A.; Croia, M.; Di Giovenale, D.; Ferrario, M.; Filippi, F.; Gallo, A.; Gatti, G.; Giorgianni, F.; Giribono, A.; Li, W.; Lupi, S.; Mostacci, A.; Petrarca, M.; Piersanti, L.; Di Pirro, G.; Romeo, S.; Scifo, J.; Shpakov, V.; Vaccarezza, C.; Villa, F.

    2016-08-01

    The generation of ultra-short electron bunches with ultra-low timing-jitter relative to the photo-cathode (PC) laser has been experimentally proved for the first time at the SPARC_LAB test-facility (INFN-LNF, Frascati) exploiting a two-stage hybrid compression scheme. The first stage employs RF-based compression (velocity-bunching), which shortens the bunch and imprints an energy chirp on it. The second stage is performed in a non-isochronous dogleg line, where the compression is completed resulting in a final bunch duration below 90 fs (rms). At the same time, the beam arrival timing-jitter with respect to the PC laser has been measured to be lower than 20 fs (rms). The reported results have been validated with numerical simulations.

  16. Femtosecond timing-jitter between photo-cathode laser and ultra-short electron bunches by means of hybrid compression

    CERN Document Server

    Pompili, Riccardo; Bellaveglia, M; Biagioni, A; Castorina, G; Chiadroni, E; Cianchi, A; Croia, M; Di Giovenale, D; Ferrario, M; Filippi, F; Gallo, A; Gatti, G; Giorgianni, F; Giribono, A; Li, W; Lupi, S; Mostacci, A; Petrarca, M; Piersanti, L; Di Pirro, G; Romeo, S; Scifo, J; Shpakov, V; Vaccarezza, C; Villa, F

    2017-01-01

    The generation of ultra-short electron bunches with ultra-low timing-jitter relative to the photo-cathode (PC) laser has been experimentally proved for the first time at the SPARC_LAB test-facility (INFN-LNF, Frascati) exploiting a two-stage hybrid compression scheme. The first stage employs RF-based compression (velocity-bunching), which shortens the bunch and imprints an energy chirp on it. The second stage is performed in a non-isochronous dogleg line, where the compression is completed resulting in a final bunch duration below 90 fs (rms). At the same time, the beam arrival timing-jitter with respect to the PC laser has been measured to be lower than 20 fs (rms). The reported results have been validated with numerical simulations.

  17. Research Update: Relativistic origin of slow electron-hole recombination in hybrid halide perovskite solar cells

    Science.gov (United States)

    Azarhoosh, Pooya; McKechnie, Scott; Frost, Jarvist M.; Walsh, Aron; van Schilfgaarde, Mark

    2016-09-01

    The hybrid perovskite CH3NH3PbI3 (MAPI) exhibits long minority-carrier lifetimes and diffusion lengths. We show that slow recombination originates from a spin-split indirect-gap. Large internal electric fields act on spin-orbit-coupled band extrema, shifting band-edges to inequivalent wavevectors, making the fundamental gap indirect. From a description of photoluminescence within the quasiparticle self-consistent GW approximation for MAPI, CdTe, and GaAs, we predict carrier lifetime as a function of light intensity and temperature. At operating conditions we find radiative recombination in MAPI is reduced by a factor of more than 350 compared to direct gap behavior. The indirect gap is retained with dynamic disorder.

  18. Research Update: Relativistic origin of slow electron-hole recombination in hybrid halide perovskite solar cells

    Directory of Open Access Journals (Sweden)

    Pooya Azarhoosh

    2016-09-01

    Full Text Available The hybrid perovskite CH3NH3PbI3 (MAPI exhibits long minority-carrier lifetimes and diffusion lengths. We show that slow recombination originates from a spin-split indirect-gap. Large internal electric fields act on spin-orbit-coupled band extrema, shifting band-edges to inequivalent wavevectors, making the fundamental gap indirect. From a description of photoluminescence within the quasiparticle self-consistent GW approximation for MAPI, CdTe, and GaAs, we predict carrier lifetime as a function of light intensity and temperature. At operating conditions we find radiative recombination in MAPI is reduced by a factor of more than 350 compared to direct gap behavior. The indirect gap is retained with dynamic disorder.

  19. Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function

    Science.gov (United States)

    Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

    2016-01-01

    In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, free-standing electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on-demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function. PMID:26974408

  20. Positron annihilation lifetime in float-zone n-type silicon irradiated by fast electrons: a thermally stable vacancy defect

    Energy Technology Data Exchange (ETDEWEB)

    Arutyunov, Nikolay [Martin Luther University Halle, Department of Physics, von-Danckelmann-Platz 3, 06120 Halle (Germany); Ioffe Physico-Technical Institute, 194021 St. Petersburg (Russian Federation); Institute of Ion-Plasma and Laser Technologies (Institute of Electronics), 700170 Tashkent (Uzbekistan); Emtsev, Vadim; Oganesyan, Gagik [Ioffe Physico-Technical Institute, 194021 St. Petersburg (Russian Federation); Krause-Rehberg, Reinhard [Martin Luther University Halle, Department of Physics, von-Danckelmann-Platz 3, 06120 Halle (Germany); Elsayed, Mohamed [Martin Luther University Halle, Department of Physics, von-Danckelmann-Platz 3, 06120 Halle (Germany); Minia University, Faculty of Science, Physics Department, 61519 Minia (Egypt); Kozlovskii, Vitalii [St. Petersburg State Polytechnical University, 195251 St. Petersburg (Russian Federation)

    2016-12-15

    Temperature dependency of the average positron lifetime has been investigated for n-type float-zone silicon, n-FZ-Si(P), subjected to irradiation with 0.9 MeV electrons at RT. In the course of the isochronal annealing a new defect-related temperature-dependent pattern of the positron lifetime spectra has been revealed. Beyond the well known intervals of isochronal annealing of acceptor-like defects such as E-centers, divacancies and A-centers, the positron annihilation at the vacancy defects has been observed in the course of the isochronal annealing from ∝ 320 C up to the limit of reliable detecting of the defect-related positron annihilation lifetime at ≥ 500 C. These data correlate with the ones of recovery of the concentration of the charge carriers and their mobility which is found to continue in the course of annealing to ∝ 570 C; the annealing is accomplished at ∝650 C. A thermally stable complex consisting of the open vacancy volume and the phosphorus impurity atom, V{sub op}-P, is suggested as a possible candidate for interpreting the data obtained by the positron annihilation lifetime spectroscopy. An extended couple of semi-vacancies, 2V{sub s-ext}, as well as a relaxed inwards a couple of vacancies, 2V{sub inw}, are suggested as the open vacancy volume V{sub op} to be probed with the positron. It is argued that a high thermal stability of the V{sub s-ext} PV{sub s-ext} (or V{sub inw}PV{sub inw.}) configuration is contributed by the efficiency of PSi{sub 5} bonding. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Biomass carbon, nitrogen and phosphorus stocks in hybrid poplar buffers, herbaceous buffers and natural woodlots in the riparian zone on agricultural land.

    Science.gov (United States)

    Fortier, Julien; Truax, Benoit; Gagnon, Daniel; Lambert, France

    2015-05-01

    In many temperate agricultural areas, riparian forests have been converted to cultivated land, and only narrow strips of herbaceous vegetation now buffer many farm streams. The afforestation of these riparian zones has the potential to increase carbon (C) storage in agricultural landscapes by creating a new biomass sink for atmospheric CO2. Occurring at the same time, the storage of nitrogen (N) and phosphorus (P) in plant biomass, is an important water quality function that may greatly vary with types of riparian vegetation. The objectives of this study were (1) to compare C, N and P storage in aboveground, belowground and detrital biomass for three types of riparian vegetation cover (9-year-old hybrid poplar buffers, herbaceous buffers and natural woodlots) across four agricultural sites and (2) to determine potential vegetation cover effects on soil nutrient supply rate in the riparian zone. Site level comparisons suggest that 9-year-old poplar buffers have stored 9-31 times more biomass C, 4-10 times more biomass N, and 3-7 times more biomass P than adjacent non managed herbaceous buffers, with the largest differences observed on the more fertile sites. The conversion of these herbaceous buffers to poplar buffers could respectively increase C, N and P storage in biomass by 3.2-11.9 t/ha/yr, 32-124 kg/ha/yr and 3.2-15.6 kg/ha/yr, over 9 years. Soil NO3 and P supply rates during the summer were respectively 57% and 66% lower in poplar buffers than in adjacent herbaceous buffers, potentially reflecting differences in nutrient storage and cycling between the two buffer types. Biomass C ranged 49-160 t/ha in woodlots, 33-110 t/ha in poplar buffers and 3-4 t/ha in herbaceous buffers. Similar biomass C stocks were found in the most productive poplar buffer and three of the four woodlots studied. Given their large and varied biomass C stocks, conservation of older riparian woodlots is equally important for C balance management in farmland. In addition, the

  2. Graphene/MoS2 hybrid technology for large-scale two-dimensional electronics.

    Science.gov (United States)

    Yu, Lili; Lee, Yi-Hsien; Ling, Xi; Santos, Elton J G; Shin, Yong Cheol; Lin, Yuxuan; Dubey, Madan; Kaxiras, Efthimios; Kong, Jing; Wang, Han; Palacios, Tomás

    2014-06-11

    Two-dimensional (2D) materials have generated great interest in the past few years as a new toolbox for electronics. This family of materials includes, among others, metallic graphene, semiconducting transition metal dichalcogenides (such as MoS2), and insulating boron nitride. These materials and their heterostructures offer excellent mechanical flexibility, optical transparency, and favorable transport properties for realizing electronic, sensing, and optical systems on arbitrary surfaces. In this paper, we demonstrate a novel technology for constructing large-scale electronic systems based on graphene/molybdenum disulfide (MoS2) heterostructures grown by chemical vapor deposition. We have fabricated high-performance devices and circuits based on this heterostructure, where MoS2 is used as the transistor channel and graphene as contact electrodes and circuit interconnects. We provide a systematic comparison of the graphene/MoS2 heterojunction contact to more traditional MoS2-metal junctions, as well as a theoretical investigation, using density functional theory, of the origin of the Schottky barrier height. The tunability of the graphene work function with electrostatic doping significantly improves the ohmic contact to MoS2. These high-performance large-scale devices and circuits based on this 2D heterostructure pave the way for practical flexible transparent electronics.

  3. Interface Engineering for Organic Electronics; Manufacturing of Hybrid Inorganic-Organic Molecular Crystal Devices

    NARCIS (Netherlands)

    de Veen, P.J.

    2011-01-01

    Organic semiconductors are at the basis of Organic Electronics. Objective of this dissertation is “to fabricate high-quality organic molecular single-crystal devices”, to explore the intrinsic properties of organic semiconductors. To achieve this, the in situ fabrication of complete field-effect

  4. Flow Regime Transition in Inner Grooved Minichannel Cold Plates for Cooling Hybrid Electric Power Electronics

    Science.gov (United States)

    2013-01-01

    system to create a military base microgrid (1). There are several motivations for replacing the traditional internal combustion (IC) motors and...appropriate control electronics, several HEVs can form a microgrid with a robust source of utility power (1). This use of HEVs can reduce the need for

  5. Multiplex PCR, amplicon size and hybridization efficiency on the NanoChip electronic microarray

    DEFF Research Database (Denmark)

    Børsting, Claus; Sanchez, Juan J; Morling, Niels

    2004-01-01

    We tested the SNP typing protocol developed for the NanoChip electronic microarray by analyzing the four Y chromosome loci SRY1532, SRY8299, TAT, and 92R7. Amplicons of different lengths containing the same locus were purified and addressed to the NanoChip array and fluorescently labelled reporter...

  6. An extensive candidate gene approach to speciation: diversity, divergence and linkage disequilibrium in candidate pigmentation genes across the European crow hybrid zone.

    Science.gov (United States)

    Poelstra, J W; Ellegren, H; Wolf, J B W

    2013-12-01

    Colouration patterns have an important role in adaptation and speciation. The European crow system, in which all-black carrion crows and grey-coated hooded crows meet in a narrow hybrid zone, is a prominent example. The marked phenotypic difference is maintained by assortative mating in the absence of neutral genetic divergence, suggesting the presence of few pigmentation genes of major effect. We made use of the rich phenotypic and genetic resources in mammals and identified a comprehensive panel of 95 candidate pigmentation genes for birds. Based on functional annotation, we chose a subset of the most promising 37 candidates, for which we developed a marker system that demonstrably works across the avian phylogeny. In total, we sequenced 107 amplicons (∼3 loci per gene, totalling 60 kb) in population samples of crows (n=23 for each taxon). Tajima's D, Fu's FS, DHEW and HKA (Hudson-Kreitman-Aguade) statistics revealed several amplicons that deviated from neutrality; however, none of these showed significantly elevated differentiation between the two taxa. Hence, colour divergence in this system may be mediated by uncharacterized pigmentation genes or regulatory regions outside genes. Alternatively, the observed high population recombination rate (4Ner∼0.03), with overall linkage disequilibrium dropping rapidly within the order of few 100 bp, may compromise the power to detect causal loci with nearby markers. Our results add to the debate as to the utility of candidate gene approaches in relation to genomic features and the genetic architecture of the phenotypic trait in question.

  7. In-situ spectroscopy and nanoscale electronics in superconductor-topological insulator hybrid devices: a combined thin film growth and quantum transport study

    NARCIS (Netherlands)

    Ngabonziza, Prosper

    2016-01-01

    In this dissertation, we presented a combined thin film growth and quantum transport study on superconductor topological insulator hybrid devices. Understanding of the electronic properties of topological insulators (TIs), their preparation in high quality thin film form and their interaction with o

  8. Electron hybridization and anharmonic thermal vibration effect on structure transition of SrTiO3 at high-pressure and low-temperature

    Science.gov (United States)

    Yamanaka, Takamitsu; Ahart, Muhtar; Mao, Ho-kwang; Suzuki, Takeyuki

    2017-01-01

    We execute electron density analysis of SrTiO3 at low temperatures up 80 K and high pressures up to 11.88 GPa using X-ray single-crystal diffraction and ab initio quantum chemical molecular orbital (MO) calculation. By changing pressures, the cubic SrTiO3 with perovskite structure goes through a antiferroelastic distortion to tetragonal symmetry above the critical pressure Pc=7 GPa with c/a1 and increasing with lowering temperature. Difference Fourier (D-F) synthesis experimentally proves the residual electron densities Δρ(xyz) are associated with two different effects: electron hybridization bonding electron and anharmonic thermal vibration atoms. The d-p-π hybridization between Ti(3d) and O(2p) orbitals is confirmed in the residual electron density, which is deformed from the ideal spherical density conducted by the atomic scattering factor fi using Hartree-Fock (HF) approximation. MO calculation also reveals the electron hybridization. Anharmonic thermal vibration of atoms yields a large effect to the structure transition. Mulliken charges analysis of MO calculation indicates much smaller charges than their formal ionic charges. Their ionicity increases from cubic to tetragonal above Pc and below Tc.

  9. Electron microscopic observations of the anterior pituitary gland. Part I. The neurons in the "transitional zone" of the anterior pituitary gland.

    Science.gov (United States)

    Mabuchi, Yoshio; Shirasawa, Nobuyuki; Sakuma, Eisuke; Wada, Ikuo; Horiuchi, Osamu; Kikuchi, Motoshi; Sakamoto, Atsushi; Herbert, Damon C; Soji, Tsuyoshi

    2008-06-01

    Since [Westlud, K.N., Chils, G.V., 1982. Localization of serotonin fibers in the rat adenohypophysis. Endocrinology 111, 1761-1763] initially identified the serotonin nerve fibers in the anterior pituitary gland, attention has been paid to the rostral zone of the anterior lobe into which nerve fibers enter and subsequently spread to deeper regions of the lobe. The rostral zone is the trifurcated junction of the partes tuberalis, intermedia and distalis, and has the important role(s) for hormone secretion via the "transitional zone" [Sato, G, Shirasawa, N, Sakuma, E, Sato, Y, Asai, Y, Wada, I, Horiuchi, O, Sakamoto, A, Herbert, DC, Soji, T, 2005a. Intercellular communications within the rat anterior pituitary. XI: An immunohistochemical study of distributions of S-100 positive cells in the anterior pituitary of the rat. Tissue and Cell 37, 269-280.]. The objective of this study was to focus on the ultrastructure of this "zone." All of the animals studied were fixed by perfusion with glutaraldehyde via the left ventricle of the heart and examined by electron microscopy. In the "transitional zone," a cluster of neuronal elements was observed between the folliculo-stellate cell-rich area and the anterior lobe. This cluster consisted of myelinated fibers, unmyelinated fibers, neuroendocrine fibers, large cells, and supporting cells. The large cells were perikarya of neurons which made a "ganglion-like" structure with associated satellite cells. Agranular, folliculo-stellate cells were intermingled among the elements. This is the first report that neuronal elements form clusters in the "transitional zone." A relationship of the unmyelinated and neuroendocrine fibers in the basal layer and in the "transitional zone" is discussed.

  10. Severe local strain and the plastic deformation of Guinier-Preston zones in the Al-Ag system revealed by three-dimensional electron tomography

    Energy Technology Data Exchange (ETDEWEB)

    Inoke, Koji [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Room 650, West 4 Building, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); FEI Company Japan Ltd., 13-34, Kohnan 2, Minato-ku, Tokyo 108-0075 (Japan); Kaneko, Kenji [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Room 650, West 4 Building, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)]. E-mail: kaneko@zaiko.kyushu-u.ac.jp; Weyland, Matthew [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Midgley, Paul A. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ (United Kingdom); Higashida, Kenji [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Room 650, West 4 Building, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Horita, Zenji [Department of Materials Science and Engineering, Faculty of Engineering, Kyushu University, Room 650, West 4 Building, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan)

    2006-06-15

    A severe bulk strain, {gamma} {approx} 1, intentionally introduced into an Al-Ag specimen by the equal-channel angular pressing process caused nearly spherical Guinier-Preston (GP) zones and {l_brace}1 1 1{r_brace} planar {gamma}' phases to be sheared by dislocation motion. Although distortion of GP zones in the Al-Ag system was observed by Nicholson and Nutting in 1961, the three-dimensional morphology or the amount of strain of the deformed GP zones has not been studied to date. The presence of fine-scale distorted (ellipsoidal) GP zones parallel to the {l_brace}1 1 1{r_brace} slip planes is revealed using three-dimensional atomic number, Z-contrast electron tomography. The GP zones lie within localized shear bands, which result from the introduction of the severe strain. The local shear strain, measured at the nanoscale, within the shear band was determined to be 1.83 {+-} 0.272, a value considerably more than previously expected.

  11. Microstructure, chemistry, and electronic structure of natural hybrid composites in abalone shell.

    Science.gov (United States)

    Srot, Vesna; Wegst, Ulrike G K; Salzberger, Ute; Koch, Christoph T; Hahn, Kersten; Kopold, Peter; van Aken, Peter A

    2013-05-01

    The crystal structure and chemical composition at the inorganic/inorganic and inorganic/organic interfaces in abalone shell (genus Haliotis) were investigated using advanced analytical transmission electron microscopy (TEM) methods. Electron energy-loss near-edge structures (ELNES) of Ca-M2,3, C-K, Ca-L2,3, O-K and low-loss EEL spectra acquired from aragonite and calcite are distinctly different. When comparing biogenic with inorganic material for aragonite, only minor differences in C-K fine structures could be detected. The crystal structure of the mineral bridges was confirmed by ELNES experiments. ELNES and energy-filtered TEM (EFTEM) experiments of regular and self-healed interfaces between nacreous aragonite and prismatic calcite reveal relatively rough transitions. In this work, the importance of TEM specimen preparation and specimen damage on structural features is discussed.

  12. Electronic and mechanical properties of hybrid graphene/h-BN nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Pooja,, E-mail: j.poojaa1228@gmail.com; Sharma, Munish; Ahluwalia, P. K. [Physics Department, Himachal Pradesh University, Shimla-171005 (India); Kumar, Ashok [Physics Department, Panjab University, Chandigarh-160014 (India); Thakur, Anil [Physics Department, Govt. Collage Solan, Himachal Pradesh-173212 (India)

    2015-06-24

    The electronic and mechanical properties of one-dimensional super lattice which are composed of controlled domain size of graphene and h-BN nanoribbons with saturated and unsaturated edges are studied by means of the first-principles method. The results show that the studied zigzag- nanoribbons (Z-GBNNR) with unsaturated edges are half-metallic, while they transform into non-magnetic semiconductor on hydrogen passivations. On the other hand the band-gap of armchair-edges nanoribbons (A-GBNNR) get enhanced by the edges saturation. Furthermore, unsaturated edges A-GBNNR and saturated edges Z-GBNNR are found mechanically more stable. These results provide a fingerprint for their use in spintronics and electronics devices.

  13. Role of microstructure in the electron-hole interaction of hybrid lead halide perovskites

    Science.gov (United States)

    Grancini, Giulia; Srimath Kandada, Ajay Ram; Frost, Jarvist M.; Barker, Alex J.; de Bastiani, Michele; Gandini, Marina; Marras, Sergio; Lanzani, Guglielmo; Walsh, Aron; Petrozza, Annamaria

    2015-10-01

    Organic-inorganic metal halide perovskites have demonstrated high power conversion efficiencies in solar cells and promising performance in a wide range of optoelectronic devices. The existence and stability of bound electron-hole pairs in these materials and their role in the operation of devices with different architectures remains a controversial issue. Here we demonstrate, through a combination of optical spectroscopy and multiscale modelling as a function of the degree of polycrystallinity and temperature, that the electron-hole interaction is sensitive to the microstructure of the material. The long-range order is disrupted by polycrystalline disorder and the variations in electrostatic potential found for smaller crystals suppress exciton formation, while larger crystals of the same composition demonstrate an unambiguous excitonic state. We conclude that fabrication procedures and morphology strongly influence perovskite behaviour, with both free carrier and excitonic regimes possible, with strong implications for optoelectronic devices.

  14. Hybrid optical-electrochemical electronic nose system based on Zn-porphyrin and multi-walled carbon nanotube composite.

    Science.gov (United States)

    Kladsomboon, Sumana; Lutz, Mario; Pogfay, Tawee; Puntheeranurak, Theeraporn; Kerdcharoen, Teerakiat

    2012-07-01

    In this work, we have enhanced the capability of an e-nose system based on combined optical and electrochemical transduction within a single gas sensor array. The optical part of this e-nose is based on detection of the absorption changes of light emitted from eight light emitting diodes (LEDs) as measured by a CMOS photo-detector. The electrochemical part works by measuring the change in electrical resistivity of the sensing materials upon contact with the sample vapor. Zinc-5,10,15,20-tetra-phenyl-21H,23H-porphyrin (ZnTPP) and multi-walled carbon nanotube (MWCNT) composite was used as the sensing materials based on its good optoelectronic properties. This sensing layer was characterized by UV-Vis spectroscopy and atomic force microscope and tested with various VOC vapors. Density functional theory (DFT) calculations were performed to investigate the electronic properties and interaction energies between ZnTPP and analyte molecules. It can be clearly seen that this hybrid optical-electrochemical electronic nose system can classify the vapor of different volatile organic compounds.

  15. Electronic, structural, and thermodynamic properties of mixed actinide dioxides (U, Pu, Am) O2 from hybrid density functional theory

    Science.gov (United States)

    Ma, Li; Ray, Asok K.

    2010-03-01

    As a continuation of our studies of pure actinide metals using hybrid density functional theory,footnotetextR. Atta-Fynn and A. K. Ray, Europhysics Letters, 85, 27008-p1- p6 (2009); Chemical Physics Letters, 482, 223-227 (2009). we present here a systematic study of the electronic and geometric structure properties of mixed actinide dioxides, U0.5Pu0.5O2, U0.5Am0.5O2, Pu0.5Am0.5 O2 and U0.8Pu0.2O2. The fraction of exact Hartree-Fock exchange used was 40%. To investigate the effect of spin-orbit coupling on the ground state electronic and geometric structure properties, computations have been carried out at two theoretical levels, one at the scalar-relativistic level with no spin-orbit coupling and one at the fully relativistic level with spin-orbit coupling. Thermodynamic properties have been calculated by a coupling of first-principles calculation and lattice dynamics.

  16. Defects Energetics and Electronic Properties of Li Doped ZnO: A Hybrid Hartree-Fock and Density Functional Study

    Institute of Scientific and Technical Information of China (English)

    Xu Sun; You-song Gu; Xue-qiang Wang; Yue Zhang

    2012-01-01

    The electronic properties and stability of Li-doped ZnO with various defects have been studied by calculating the electronic structures and defect formation energies via first-principles calculations using hybrid Hartree-Fock and density functional methods.The results from formation energy calculations show that Li pair complexes have the lowest formation energy in most circumstances and they consume most of the Li content in Li doped ZnO,which make the p-type conductance hard to obtain.The formation of Li pair complexes is the main obstacle to realize p-type conductance in Li doped ZnO.However,the formation energy of Lizn decreases as environment changes from Zn-rich to O-rich and becomes more stable than that of Li-pair complexes at highly O-rich environment.Therefore,p-type conductance can be obtained by Li doped ZnO grown or post annealed in oxygen rich atmosphere.

  17. The impact of the semiconductor emitting diode brightness distribution on the energy sensitivity of the opto-electronic system with the optical equisignal zone

    Science.gov (United States)

    Nekrylov, Ivan S.; Timofeev, Alexander N.; Kleshchenok, Maksim A.

    2016-04-01

    The research of the influence of the LED radiation brightness distribution on the energy sensitivity of optical-electronic systems with optical equal zone is provided. Mathematical modeling of the radiation field on a matrix receiver, considering lens spherical aberration, is provided. The possibility of forming a uniform illumination on the photo-detector matrix, changing the shape of the distribution of the brightness of the LED at a predetermined invariable spherical aberration of the lens is provided.

  18. Spin-triplet electron transport in hybrid superconductor heterostructures with a composite ferromagnetic interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Sheyerman, A. E., E-mail: karen@hitech.cplire.ru; Constantinian, K. Y.; Ovsyannikov, G. A.; Kislinskii, Yu. V.; Shadrin, A. V. [Russian Academy of Sciences, Kotelnikov Institute of Radio Engineering and Electronics (Russian Federation); Kalabukhov, A. V. [Chalmers University of Technology (Sweden); Khaydukov, Yu. N. [Max-Planck Institute for Solid State Research (Germany)

    2015-06-15

    Hybrid YBa{sub 2}Cu{sub 3}O{sub 7−x}/SrRuO{sub 3}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/Au-Nb superconductor mesastructures with a composite manganite-ruthenate ferromagnetic interlayer are studied using electrophysical, magnetic, and microwave methods. The supercurrent in the mesastructure is observed when the interlayer thickness is much larger than the coherence length of ferromagnetic materials. The peak on the dependence of the critical current density on the interlayer material thickness corresponds to the coherence length, which is in qualitative agreement with theoretical predictions for a system with spit-triplet superconducting correlations. The magnetic-field dependence of the critical current is determined by penetration of magnetic flux quanta and by the magnetic domain structure, as well as by the field dependence of disorientation of the magnetization vectors of the layers in the composite magnetic interlayer. It is found that the supercurrent exists in magnetic fields two orders of magnitude stronger than the field corresponding to entry of a magnetic flux quantum into the mesastructure. The current-phase relation (CPR) of the supercurrent of mesastructures is investigated upon a change in the magnetic field from zero to 30 Oe; the ratio of the second CPR harmonic to the first, determined from the dependence of the Shapiro steps on the microwave radiation amplitude, does not exceed 50%.

  19. A hybrid electronic tongue for direct classification of baby liquid foods with or without gluten

    OpenAIRE

    Peres, António M.; Dias, L. G.; Veloso, Ana C. A.; Sousa, Mara E.B.C.; Machado, A.A.S.C.

    2011-01-01

    People suffering from celiac disease are gluten intolerant and inadvertent ingestion of gluten proteins must be avoided. Several techniques have been proposed to detect/quantify gluten proteins in foodstuffs: immunochemical methods, mass tandem spectrometry and polymerase chain reaction as well as gluten sensors [1]. Recently, a potentiometric electronic tongue (ET) with lipo/polymeric membranes has been used to detect gliadins, which are gluten proteins, in foodstuffs [2]. How...

  20. Realizing the Hybrid Library.

    Science.gov (United States)

    Pinfield, Stephen; Eaton, Jonathan; Edwards, Catherine; Russell, Rosemary; Wissenburg, Astrid; Wynne, Peter

    1998-01-01

    Outlines five projects currently funded by the United Kingdom's Electronic Libraries Program (eLib): HyLiFe (Hybrid Library of the Future), MALIBU (MAnaging the hybrid Library for the Benefit of Users), HeadLine (Hybrid Electronic Access and Delivery in the Library Networked Environment), ATHENS (authentication scheme), and BUILDER (Birmingham…

  1. Hybrid-PIC modeling of laser-plasma interactions and hot electron generation in gold hohlraum walls

    Science.gov (United States)

    Thoma, C.; Welch, D. R.; Clark, R. E.; Rose, D. V.; Golovkin, I. E.

    2017-06-01

    The walls of the hohlraum used in experiments at the national ignition facility are heated by laser beams with intensities ˜ 10 15 W/cm2, a wavelength of ˜ 1 / 3 μm, and pulse lengths on the order of a ns, with collisional absorption believed to be the primary heating mechanism. X-rays generated by the hot ablated plasma at the gold walls are then used to implode a target in the hohlraum interior. In addition to the collisional absorption of laser energy at the walls, non-linear laser-plasma interactions (LPI), such as stimulated Raman scattering and two plasmon decay, are believed to generate a population of supra-thermal electrons which, if present in the hohlraum, can have a deleterious effect on target implosion. We describe results of hohlraum modeling using a hybrid particle-in-cell code. To enable this work, new particle-based algorithms for a multiple-ion magneto-hydrodynamic (MHD) treatment, and a particle-based ray-tracing model were developed. The use of such hybrid methods relaxes the requirement to resolve the laser wavelength, and allows for relatively large-scale hohlraum simulations with a reasonable number of cells. But the non-linear effects which are believed to be the cause of hot electron generation can only be captured by fully kinetic simulations with good resolution of the laser wavelength. For this reason, we employ a two-tiered approach to hohlraum modeling. Large-scale simulations of the collisional absorption process can be conducted using the fast quasi-neutral MHD algorithm with fluid particle species. From these simulations, we can observe the time evolution of the hohlraum walls and characterize the density and temperature profiles. From these results, we can transition to smaller-scale highly resolved simulations using traditional kinetic particle-in-cell methods, from which we can fully model all of the non-linear laser-plasma interactions, as well as assess the details of the electron distribution function. We find that vacuum

  2. {ital s} -{ital p} Hybridization and Electron Shell Structures in Aluminum Clusters: A Photoelectron Spectroscopy Study

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Wu, H.; Wang, X.; Wang, L. [Department of Physics, Washington State University, 2710 University Drive, Richland, Washington 99352-1671 (United States)]|[W. R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, MS K8-88, P.O. Box 999, Richland, Washington 99352 (United States)

    1998-08-01

    Using photoelectron spectroscopy of size-selected Al{sub x}{sup {minus}} (x=1{endash}162) clusters, we studied the electronic structure evolution of Al{sub x} and observed that the Al 3s - and 3p -derived bands evolve and broaden with cluster size and begin to overlap at Al{sub 9} . Direct spectroscopic signatures were obtained for electron shell structures with spherical shell closings at Al{sub 11}{sup {minus}} , Al{sub 13}{sup {minus}} , Al{sub 19}{sup {minus}} , Al{sub 23}{sup {minus}} , Al{sub 35}{sup {minus}} , Al{sub 37}{sup {minus}} , Al{sub 46} , Al{sub 52} , Al{sub 55}{sup {minus}} , Al{sub 56} , Al{sub 66} , and Al{sub 73}{sup {minus}} . The electron shell effect diminishes above Al{sub 75} and new spectral features appearing in Al{sub x}{sup {minus}} (x{gt}100) suggest a possible geometrical packing effect in large clusters. {copyright} {ital 1998} {ital The American Physical Society}

  3. Photon counting performance measurements of transfer electron InGaAsP photocathode hybrid photomultiplier tubes at 1064 nm wavelength

    Science.gov (United States)

    Sun, Xiaoli; Krainak, Michael A.; Hasselbrack, William B.; La Rue, Ross A.

    2007-05-01

    We report the test results of a hybrid photomultiplier tube (HPMT) with a transfer electron (TE) InGaAsP photocathode and GaAs Schottky avalanche photodiode (APD) anode. Unlike Geiger mode InGaAsP APDs, these HPMTs (also known as intensified photodiode (IPD), vacuum APD, or hybrid photodetector) operate in linear mode without the need for quenching and gating. Their greatest advantages are wide dynamic range, high speed, large photosensitive area, and potential for photon counting and analog detection dual mode operation. The photon detection efficiency we measured was 25% at 1064 nm wavelength with a dark count rate of 60,000/s at -22 degrees Celsius. The output pulse width in response to a single photon detection is about 0.9 ns. The maximum count rate was 90 Mcts/s and was limited solely by the speed of the discriminator used in the measurement (10 ns dead time). The spectral response of these devices extended from 900 to 1300 nm. We also measured the HPMT response to 60 ps laser pulses. The average output pulse amplitude increased monotonically with the input pulse energy, which suggested that we can resolve photon number in an incident pulse. The jitter of the HPMT output was found to be about 0.5 ns standard deviation and depended on bias voltage applied to the TE photocathode. To our knowledge, these HPMTs are the most sensitive non gating photon detectors at 1064 nm wavelength, and they will have many applications in laser altimeters, atmospheric lidars, and free space laser communication systems.

  4. Incorporation of the electron energy equation into the hybrid Monte Carlo - fluid model for glow discharge: the applicability and reliability of the model

    Science.gov (United States)

    Eylenceoglu, Ender; Rafatov, Ismail; Kudryavtsev, Anatoly

    2016-09-01

    A modification of the conventional hybrid Monte Carlo - fluid model for glow discharge, which incorporates the electron energy equation, is considered. In the proposed model electrons are separated into two groups, namely, high energetic fast and low energetic slow (bulk) electrons. Density profiles of ions, slow electrons, and meta-stable particles are determined from the solution of corresponding continuity equations. Fast electrons, which are responsible for ionization and excitation events in the discharge, are simulated by the Monte-Carlo method. The temperature profile for slow electrons is obtained from the solution of the energy balance equation. The transport (mobility and diffusion) coefficients as well as the reaction rates for slow electrons are determined as functions of the electron temperature. Test calculations are carried out for the direct current glow discharge in argon within two-dimensional geometry. Comparison of the computed results with those obtained from the conventional fluid and hybrid models and the experimental data is done, the applicability and reliability of the proposed model is studied in details.

  5. A hybrid approach to simulation of electron transfer in complex molecular systems

    Science.gov (United States)

    Kubař, Tomáš; Elstner, Marcus

    2013-01-01

    Electron transfer (ET) reactions in biomolecular systems represent an important class of processes at the interface of physics, chemistry and biology. The theoretical description of these reactions constitutes a huge challenge because extensive systems require a quantum-mechanical treatment and a broad range of time scales are involved. Thus, only small model systems may be investigated with the modern density functional theory techniques combined with non-adiabatic dynamics algorithms. On the other hand, model calculations based on Marcus's seminal theory describe the ET involving several assumptions that may not always be met. We review a multi-scale method that combines a non-adiabatic propagation scheme and a linear scaling quantum-chemical method with a molecular mechanics force field in such a way that an unbiased description of the dynamics of excess electron is achieved and the number of degrees of freedom is reduced effectively at the same time. ET reactions taking nanoseconds in systems with hundreds of quantum atoms can be simulated, bridging the gap between non-adiabatic ab initio simulations and model approaches such as the Marcus theory. A major recent application is hole transfer in DNA, which represents an archetypal ET reaction in a polarizable medium. Ongoing work focuses on hole transfer in proteins, peptides and organic semi-conductors. PMID:23883952

  6. Bionano donor-acceptor hybrids of porphyrin, ssDNA, and semiconductive single-wall carbon nanotubes for electron transfer via porphyrin excitation.

    Science.gov (United States)

    D'Souza, Francis; Das, Sushanta K; Zandler, Melvin E; Sandanayaka, Atula S D; Ito, Osamu

    2011-12-14

    Photoinduced electron transfer in self-assemblies of porphyrins ion-paired with ssDNA wrapped around single-wall carbon nanotubes (SWCNTs) has been reported. To accomplish the three-component hybrids, two kinds of diameter-sorted semiconducting SWCNT(n,m)s of different diameter ((n,m) = (6,5) and (7,6)) and free-base or zinc porphyrin bearing peripheral positive charges ((TMPyP(+))M (tetrakis(4-N-methylpyridyl)porphyrin); M = Zn and H(2)) serving as light-absorbing photoactive materials are utilized. The donor-acceptor hybrids are held by ion-pairing between the negatively charged phosphate groups of ssDNA on the surface of the SWCNT and the positively charged at the ring periphery porphyrin macrocycle. The newly assembled bionano donor-acceptor hybrids have been characterized by transmission electron microscopy (TEM) and spectroscopic methods. Photoinduced electron transfer from the excited singlet porphyrin to the SWCNTs directly and/or via ssDNA as an electron mediator has been established by performing systematic studies involving the steady-state and time-resolved emission as well as the transient absorption studies. Higher charge-separation efficiency has been successfully demonstrated by the selection of the appropriate semiconductive SWCNTs with the right band gap, in addition to the aid of ssDNA as the electron mediator. © 2011 American Chemical Society

  7. Low-temperature electronic transport in one-dimensional hybrid systems: Metal cluster embedded carbon nanotubes

    Science.gov (United States)

    Soldano, Caterina

    The investigation of the electronic and magnetotransport properties at low temperature in individual MWNT with embedded clusters are here presented. The majority of studies of transport in MWNT reported in literature has been carried out on arc-discharge grown tubes, generally considered "clean" and defect-free. In this project, individual MWNT grown in alumina template are used; these tubes are highly disordered compared for example to arc-discharge ones, conditions that dramatically will impact the charge transport. As-fabricated devices are in general highly resistive. A large decrease in the value of the device resistance can be achieved through a controlled and fast high-bias sweep method (HBT) across the sample. Scanning electron microscopy analysis shows that this method induces a metal (platinum) decoration of the MWNT surface as a consequence of the large amount of Joule heating developed during the sweep. Temperature dependence study (5wires. DFT calculations show that the enhancement in conductance can be explained in term of enhanced density of states around the Fermi energy due to presence of platinum on the wall. Magneto-transport measurements carried out up to a value of magnetic field up to |5|T show a clear dependence from the energy (i.e. applied bias). A nearly symmetric and monotonically increasing positive magneto-conductance is observed in the range of the applied field, confirming the presence of weak localization in the system. A small but distinct Rashba spin-orbit scattering effect in the magneto-conductance in the low-field regime (|B|<.5T) is found and attributed to the surface decoration. Electronic and magnetotransport measurements independently confirm the 1D nature of the transport in the system. "Zero-field" measurements were performed on magnetic cluster-embedded MWNT-based devices (FM-MWNT). Temperature dependence of the conductance reveals a Luttinger liquid type of behavior in the range of investigated temperatures but no

  8. Hermetically sealable package for hybrid solid-state electronic devices and the like

    Science.gov (United States)

    Miller, Wilson N. (Inventor); Gray, Ormal E. (Inventor)

    1988-01-01

    A light-weight, inexpensively fabricated, hermetically sealable, repairable package for small electronic or electromechanical units, having multiple connections, is described. A molded ring frame of polyamide-imide plastic (Torlon) is attached along one edge to a base plate formed of a highly heat conducting material, such as aluminum or copper. Bores are placed through a base plate within the area of the edge surface of ring frame which result in an attachment of the ring frame to the base plate during molding. Electrical leads are molded into the ring frame. The leads are L-shaped gold-plated copper wires imbedded within widened portions of the side wall of the ring frame. Within the plastic ring frame wall the leads are bent (typically, though not necessarily at 90 deg) so that they project into the interior volume of the ring frame for connection to the solid state devices.

  9. RECOMMEND OF HIGH-YIELDING HYBRID MILLET DEVELOPMENT IN CENTRAL ARID ZONE OF NINGXIA%宁夏中部干旱带发展高产杂交谷子产业的建议

    Institute of Scientific and Technical Information of China (English)

    马力文; 刘静; 周斌; 刘维斌; 杨立文; 席国术

    2016-01-01

    Ningxia is a severe water scarcity province in China. Under the background of global warming, the drought on central arid zone has intensified, the contradiction between water supply and demand is increasingly prominent, and food production is low and long-term instability. Ecological migrants faced enormous pressure to get rid of poverty, and survival and development problems became prominent. Since 2010, Ningxia meteorological department successfully introduced a series of hybrid millet varieties in the central arid zone, carried out a large se-ries of hybrid millet experimental study, and promoted the planting areas to nearly 667hm2 . In this paper, under the very dry year of 2011 , the comparative cost-effectiveness and prospects of high-yielding hybrid millet with local mainly cultivars was analyzed. The results showed that the cultivation of hybrid millet can save water resources, re-sist heavy drought, and increase more than double yield comparing with the traditional local millet yields. Due to the high price of small grains, farmers' income was generally higher than that planting other crops. Based on the Zhang hybrid millet experiment and demonstration, combined with the distribution of agricultural climate resources, the Ningxia Zhang hybrid millet cultivated climatic suitability zoning map was obtained. Different areas suitable va-rieties for cultivation, methods and planting risks were analyzed. It recommended to actively and steadily develop hybrid millet cultivation in the central arid zone of Ningxia,strengthen hybrid millet yield cultivation and water-saving technology training, and establish millet cultivation-processing-marketing service system becoming a new way for the central arid zone farmers to get rich.%宁夏水资源严重匮乏,在全球气候变暖背景下,中部干旱带干旱有所加剧,水资源供需矛盾日益突出,粮食产量长期低而不稳,生态移民脱贫压力大,生存与发展问题突出.2010

  10. Co-functionalized organic/inorganic hybrid ZnO nanorods as electron transporting layers for inverted organic solar cells

    Science.gov (United States)

    Ambade, Swapnil B.; Ambade, Rohan B.; Eom, Seung Hun; Baek, Myung-Jin; Bagde, Sushil S.; Mane, Rajaram S.; Lee, Soo-Hyoung

    2016-02-01

    In an unprecedented attempt, we present an interesting approach of coupling solution processed ZnO planar nanorods (NRs) by an organic small molecule (SM) with a strong electron withdrawing cyano moiety and the carboxylic group as binding sites by a facile co-functionalization approach. Direct functionalization by SMs (SM-ZnO NRs) leads to higher aggregation owing to the weaker solubility of SMs in solutions of ZnO NRs dispersed in chlorobenzene (CB). A prior addition of organic 2-(2-methoxyethoxy)acetic acid (MEA) over ZnO NRs not only inhibits aggregation of SMs over ZnO NRs, but also provides enough sites for the SM to strongly couple with the ZnO NRs to yield transparent SM-MEA-ZnO NRs hybrids that exhibited excellent capability as electron transporting layers (ETLs) in inverted organic solar cells (iOSCs) of P3HT:PC60BM bulk-heterojunction (BHJ) photoactive layers. A strongly coupled SM-MEA-ZnO NR hybrid reduces the series resistance by enhancing the interfacial area and tunes the energy level alignment at the interface between the (indium-doped tin oxide, ITO) cathode and BHJ photoactive layers. A significant enhancement in power conversion efficiency (PCE) was achieved for iOSCs comprising ETLs of SM-MEA-ZnO NRs (3.64%) advancing from 0.9% for pristine ZnO NRs, while the iOSCs of aggregated SM-ZnO NRs ETL exhibited a much lower PCE of 2.6%, thus demonstrating the potential of the co-functionalization approach. The superiority of the co-functionalized SM-MEA-ZnO NRs ETL is also evident from the highest PCE of 7.38% obtained for the iOSCs comprising BHJ of PTB7-Th:PC60BM compared with extremely poor 0.05% for non-functionalized ZnO NRs.In an unprecedented attempt, we present an interesting approach of coupling solution processed ZnO planar nanorods (NRs) by an organic small molecule (SM) with a strong electron withdrawing cyano moiety and the carboxylic group as binding sites by a facile co-functionalization approach. Direct functionalization by SMs (SM

  11. Haldane's rule in an avian system: using cline theory and divergence population genetics to test for differential introgression of mitochondrial, autosomal, and sex-linked loci across the Passerina bunting hybrid zone.

    Science.gov (United States)

    Carling, Matthew D; Brumfield, Robb T

    2008-10-01

    Using cline fitting and divergence population genetics, we tested a prediction of Haldane's rule: autosomal alleles should introgress more than z-linked alleles or mitochondrial haplotypes across the Passerina amoena/Passerina cyanea (Aves: Cardinalidae) hybrid zone. We screened 222 individuals collected along a transect in the Great Plains of North America that spans the contact zone for mitochondrial (two genes), autosomal (four loci) and z-linked (two loci) markers. Maximum-likelihood cline widths estimated from the mitochondrial (223 km) and z-linked (309 km) datasets were significantly narrower on average than the autosomal cline widths (466 km). We also found that mean coalescent-based estimates of introgression were larger for the autosomal loci (0.63 genes/generation, scaled to the mutation rate mu) than for both the mitochondrial (0.27) and z-linked loci (0.59). These patterns are consistent with Haldane's rule, but the among-locus variation also suggests many independently segregating loci are required to investigate introgression patterns across the genome. These results provide the first comprehensive comparison of mitochondrial, sex-linked, and autosomal loci across an avian hybrid zone and add to the body of evidence suggesting that sex chromosomes play an important role in the formation and maintenance of reproductive isolation between closely related species.

  12. Drift Loss-Cone Distributions Electrons in the Jovian Synchrotron Zone from 06 and VIP4 Models

    Science.gov (United States)

    Wang, K.; Bolton, S. J.; Gulkis, S.; Levin, S. M.

    2000-01-01

    Relativistic electrons (10-50 MeV) play an important role to account for the observed synchrotron decimetric radiation in Jupiter's inner radiation belt (L loss cone for relativistic electrons using both the O6 and VIP4 magnetic field models. Model maps of the synchrotron emission for specific electron distributions are shown for comparison.

  13. Drift Loss-Cone Distributions Electrons in the Jovian Synchrotron Zone from 06 and VIP4 Models

    Science.gov (United States)

    Wang, K.; Bolton, S. J.; Gulkis, S.; Levin, S. M.

    2000-01-01

    Relativistic electrons (10-50 MeV) play an important role to account for the observed synchrotron decimetric radiation in Jupiter's inner radiation belt (L loss cone for relativistic electrons using both the O6 and VIP4 magnetic field models. Model maps of the synchrotron emission for specific electron distributions are shown for comparison.

  14. A Hybrid MCDM Model for Improving the Electronic Health Record to Better Serve Client Needs

    Directory of Open Access Journals (Sweden)

    James J. H. Liou

    2017-10-01

    Full Text Available Although the electronic health record (EHR is a promising innovation in the healthcare industry, the implementation of EHR has been relatively slow. A theoretical structure for the exploration and improvement of this usage of EHR is proposed. Incorporating the theoretical structure of TOE (technology-organization-environment, we apply the DEMATEL (decision-making trial and evaluation laboratory technique to illustrate the influence-matrix and to construct the INRM (influential network relationship map. Based on this DEMATEL influence matrix and the fundamental concepts of ANP (Analytic Hierarchy Process, we derive influential weights for the criteria. These influential weights are then combined with the modified VIKOR (VlseKriterijumska Optimizacija I Kompromisno Resenje method to find ways to understand and enhance the usage of EHR technology. The outcome demonstrates that our model can not only be used for implementation of EHR technology, but can also be applied to analyze the gaps in performance between the aspiration level and present performance values in individual criterion/dimension.

  15. Electronic Tongue Based on Nanostructured Hybrid Films of Gold Nanoparticles and Phthalocyanines for Milk Analysis

    Directory of Open Access Journals (Sweden)

    Luiza A. Mercante

    2015-01-01

    Full Text Available The use of gold nanoparticles combined with other organic and inorganic materials for designing nanostructured films has demonstrated their versatility for various applications, including optoelectronic devices and chemical sensors. In this study, we reported the synthesis and characterization of gold nanoparticles stabilized with poly(allylamine hydrochloride (Au@PAH NPs, as well as the capability of this material to form multilayer Layer-by-Layer (LbL nanostructured films with metal tetrasulfonated phthalocyanines (MTsPc. Film growth was monitored by UV-Vis absorption spectroscopy, atomic force microscopy (AFM, and Fourier transform infrared spectroscopy (FTIR. Once LbL films have been applied as active layers in chemical sensors, Au@PAH/MTsPc and PAH/MTsPc LbL films were used in an electronic tongue system for milk analysis regarding fat content. The capacitance data were treated using Principal Component Analysis (PCA, revealing the role played by the gold nanoparticles on the LbL films electrical properties, enabling this kind of system to be used for analyzing complex matrices such as milk without any prior pretreatment.

  16. Population genetic structure and mating system in the hybrid zone between Pinus sibirica Du Tour and P. pumila (Pall. Regel at the Eastern Baikal Lake shore

    Directory of Open Access Journals (Sweden)

    E.A. Petrova

    2013-12-01

    Full Text Available Genetic structure of sympatric Pinus sibirica Du Tour and P. pumila (Pall. Regel populations and putative interspecific hybrids between them was analyzed in the Baikal Lake region (Barguzin Biosphere Natural Reserve, Davsha River basin by means of 31 allozyme loci controlling 18 enzyme systems. Several alleles at loci Adh-1, Fest-2, Lap-3, Pgi-1, Sod-3 and Skdh-1 were diagnostic for P. sibirica, while alleles typical for P. pumila were detected at loci Gdh, Got-3, Lap-3, Mdh-2, Mdh-4, Pepca, Pgi-1, Pgd-2, Pgd-3, Pgm-1 and Pgm-2. All hybrids were heterozygous for the diagnostic Skdh-2 locus. Classification into hybrids and parental species using PCA analysis of multilocus allozyme genotypes had good correspondence with diagnoses made by morphological and anatomical analyses. Approximately 27% of embryos in P. pumila seeds had P. sibirica paternal contribution, and 8% of haplotypes in effective pollen pool combined alleles typical for P. pumila and P. sibirica, and therefore were classified as pollinated by the hybrids. About 83% of embryos in seeds from the hybrids most likely originated from fertilization by P. sibirica pollen, 14% from P. pumila and 3% from hybrid trees. This result favours the view that hybrids make both male and female contributions to the reproductive output of the population and confirm the presence of backcrosses and F2 hybrids.

  17. Population genetic structure and mating system in the hybrid zone between Pinus sibirica Du Tour and P. pumila (Pall. Regel at the Eastern Baikal Lake shore

    Directory of Open Access Journals (Sweden)

    E.A. Petrova

    2013-12-01

    Full Text Available Genetic structure of sympatric Pinus sibirica Du Tour and P. pumila (Pall. Regel populations and putative interspecific hybrids between them was analyzed in the Baikal Lake region (Barguzin Biosphere Natural Reserve, Davsha River basin by means of 31 allozyme loci controlling 18 enzyme systems. Several alleles at loci Adh-1, Fest-2, Lap-3, Pgi-1, Sod-3 and Skdh-1 were diagnostic for P. sibirica, while alleles typical for P. pumila were detected at loci Gdh, Got-3, Lap-3, Mdh-2, Mdh-4, Pepca, Pgi-1, Pgd-2, Pgd-3, Pgm-1 and Pgm-2. All hybrids were heterozygous for the diagnostic Skdh-2 locus. Classification into hybrids and parental species using PCA analysis of multilocus allozyme genotypes had good correspondence with diagnoses made by morphological and anatomical analyses. Approximately 27% of embryos in P. pumila seeds had P. sibirica paternal contribution, and 8% of haplotypes in effective pollen pool combined alleles typical for P. pumila and P. sibirica, and therefore were classified as pollinated by the hybrids. About 83% of embryos in seeds from the hybrids most likely originated from fertilization by P. sibirica pollen, 14% from P. pumila and 3% from hybrid trees. This result favours the view that hybrids make both male and female contributions to the reproductive output of the population and confirm the presence of backcrosses and F2 hybrids.

  18. Population genetic structure and mating system in the hybrid zone between Pinus sibirica Du Tour and P. pumila (Pall. Regel at the Eastern Baikal Lake shore

    Directory of Open Access Journals (Sweden)

    E.A. Petrova

    2008-09-01

    Full Text Available Genetic structure of sympatric Pinus sibirica Du Tour and P. pumila(Pall. Regel populations and putative interspecific hybrids between them was analyzed in the Baikal Lake region (Barguzin Biosphere Natural Reserve, Davsha River basin by means of 31 allozyme loci controlling 18 enzyme systems. Several alleles at loci Adh-1, Fest-2, Lap-3, Pgi-1, Sod-3 and Skdh-1 were diagnostic for P.sibirica, while alleles typical for P. pumila were detected at loci Gdh, Got-3, Lap-3,Mdh-2, Mdh-4, Pepca, Pgi-1, Pgd-2, Pgd-3, Pgm-1 and Pgm-2. All hybrids were heterozygous for the diagnostic Skdh-2 locus. Classification into hybrids and parental species using PCA analysis of multilocus allozyme genotypes had good correspondence with diagnoses made by morphological and anatomical analysis.Approximately 27% of embryos in P. pumila seeds had P. sibirica paternal contribution, and 8% of haplotypes in effective pollen pool combined alleles typical for P. pumila and P. sibirica, and therefore were classified as pollinated by the hybrids. About 83% of embryos in seeds from the hybrids most likely originated from fertilization by P. sibirica pollen, 14% from P. pumila and 3% from hybrid trees.This result favours the view that hybrids make both male and female contributions to the reproductive output of the population and confirm the presence of backcrosses and F2 hybrids.

  19. Layer-by-layer assembled multilayer TiO(x) for efficient electron acceptor in polymer hybrid solar cells.

    Science.gov (United States)

    Kang, Hyunbum; Lee, Chanwoo; Yoon, Sung Cheol; Cho, Chul-Hee; Cho, Jinhan; Kim, Bumjoon J

    2010-11-16

    We demonstrate that TiO(x) nanocomposite films fabricated using electrostatic layer-by-layer (LbL) assembly improve the power conversion efficiency of photovoltaic cells compared to conventional TiO(x) films fabricated via the sol-gel process. For this study, titanium precursor/poly(allylamine hydrochloride) (PAH) multilayer films were first deposited onto indium tin oxide-coated glass to produce TiO(x) nanocomposites (TiO(x)NC). The specific effect of the LbL processed TiO(x) on photovoltaic performance was investigated using the planar bilayer TiO(x)NC and highly regioregular poly(3-hexylthiophene) (P3HT) solar cells, and the P3HT/LbL TiO(x)NC solar cells showed a dramatic increase in power efficiency, particularly in terms of the short current density and fill factor. The improved efficiency of this device is mainly due to the difference in the chemical composition of the LbL TiO(x)NC films, including the much higher Ti(3+)/Ti(4+) ratio and the highly reactive facets of crystals as demonstrated by XPS and XRD measurement, thus enhancing the electron transfer between electron donors and acceptors. In addition, the grazing incidence wide-angle X-ray scattering (GIWAXS) study revealed the presence of more highly oriented P3HT stacks parallel to the substrate on the LbL TiO(x)NC film compared to those on the sol-gel TiO(x) films, possibly influencing the hole mobility of P3HT and the energy transfer near and at the interface between the P3HT and TiO(x) layers. The results of this study demonstrate that this approach is a promising one for the design of hybrid solar cells with improved efficiency.

  20. Heterogeneous oligonucleotide-hybridization assay based on hot electron-induced electrochemiluminescence of a rhodamine label at oxide-coated aluminum and silicon electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Spehar-Deleze, Anna-Maria [Laboratory of Sensors, Actuators and Microsystems, Institute of Microtechnology, University of Neuchatel, Rue Jaquet-Droz 1, CH-2007 Neuchatel (Switzerland) and Laboratory of Inorganic and Analytical Chemistry, Helsinki University of Technology, Kemistintie 1, FIN-02015 HUT (Finland)]. E-mail: anna-maria.spehar@unine.ch; Suomi, Johanna [Laboratory of Inorganic and Analytical Chemistry, Helsinki University of Technology, Kemistintie 1, FIN-02015 HUT (Finland); Jiang Qinghong [Laboratory of Inorganic and Analytical Chemistry, Helsinki University of Technology, Kemistintie 1, FIN-02015 HUT (Finland); Rooij, Nico de [Laboratory of Sensors, Actuators and Microsystems, Institute of Microtechnology, University of Neuchatel, Rue Jaquet-Droz 1, CH-2007 Neuchatel (Switzerland); Koudelka-Hep, Milena [Laboratory of Sensors, Actuators and Microsystems, Institute of Microtechnology, University of Neuchatel, Rue Jaquet-Droz 1, CH-2007 Neuchatel (Switzerland); Kulmala, Sakari [Laboratory of Inorganic and Analytical Chemistry, Helsinki University of Technology, Kemistintie 1, FIN-02015 HUT (Finland)

    2006-07-28

    This paper describes a heterogeneous oligonucleotide-hybridization assay based on hot electron-induced electrochemiluminescence (HECL) of a rhodamine label. Thin oxide-film coated aluminum and silicon electrodes were modified with an aminosilane layer and derivatized with short, 15-mer oligonucleotides via diisothiocyanate coupling. Target oligonucleotides were conjugated with tetramethylrhodamine (TAMRA) dye at their amino modified 5' end and hybridization was detected using HECL of TAMRA. Preliminary results indicate sensitivity down to picomolar level and low nonspecific adsorption. The sensitivity was better on oxide-coated silicon compared to oxide-coated aluminum electrodes and two-base pair mismatched hybrids were successfully discriminated. The experimental results presented here might be useful for the design of disposable electrochemiluminescent DNA biosensors.

  1. Influence of array photodetectors characteristics on the accuracy of the optical-electronic system with optical equisignal zone

    Science.gov (United States)

    Gusarov, Vadim F.; Maraev, Anton A.; Timofeev, Aleksandr N.; Klimov, Aleksandr A.

    2016-04-01

    In this paper we attempt to assess the possibility of applying the array of photodetectors and digital information processing in positioning systems based on optical equisignal zone. The basic theoretical information about working principles of the system with equisignal zone and the formation of the base direction are listed. The influence on the accuracy of the positioning system some parameters such as the number and size of the array elements of the receiver, capacity analog-digital converter, aberrations of optical elements are researched. The possibility of registering the angular displacements (reversals) of the controlled object by using the developed system is shown.

  2. The nature of electronic excitations at the metal-bioorganic interface illustrated on histidine-silver hybrids.

    Science.gov (United States)

    Sanader, Željka; Mitrić, Roland; Bonačić-Koutecký, Vlasta; Bellina, Bruno; Antoine, Rodolphe; Dugourd, Philippe

    2014-01-21

    We present a joint theoretical and experimental study of the structure selective optical properties of cationic and anionic histidine-silver complexes with Ag and Ag3 which were prepared in the gas phase using mass spectroscopy coupled to electrospray ion source. Our TDDFT calculations provide general insight into the nature of electronic excitations at the metal-bioorganic interface that involve π-π* excitation within bioorganic subunits, charge transfer between two subunits and intrametallic excitations. The binding of silver to histidine, one of the most important amino acids, induces red shift in the optical absorption of protonated histidine particularly for anionic species. The presence of the smallest metallic subunit Ag3 increases the intensity of low energy transitions of histidine illustrating a metal cluster-induced enhancement of absorption of biomolecules in hybrid systems. Comparison of calculated absorption spectra with experimental photofragmentation yield provides structural assignment of the measured spectroscopic patterns. Our findings may serve to establish silver-labeling as the tool for the detection of histidine or histidine-tagged proteins.

  3. New adders using hybrid circuit consisting of three-gate single-electron transistors (TG-SETs) and MOSFETs.

    Science.gov (United States)

    Yu, YunSeop; Choi, JungBum

    2007-11-01

    A half-adder (HA) and a full-adder (FA) using hybrid circuits combining three-gate single-electron transistors (TG-SETs) with metal-oxide-semiconductor field-effect-transistors (MOSFETs) are proposed. The proposed HA consists of three TG-SETs, two enhanced-mode NMOSFETs, and two depletion-mode NMOSFETs, and the proposed FA consists of eight TG-SETs, two enhanced-mode NMOSFETs, and two depletion-mode NMOSFETs. The complexities in the HA and the FA are 7 and 12, respectively, and the worst-case delays in the HA and the FA are 1.48 ns and 2.25 ns, respectively. Compared with the conventional CMOS FA with 0.35 microm technology, the proposed FA can be constructed with 0.43 of devices, and can operate with 3.5 of worst-case delay, 1/534 of average power consumption, and 1/152 of power-delay-product (PDP). The proposed HA and FA can be operated as a half-subtractor (HS) and a full-subtractor (FS) in the case when the levels of the control gates in the HA and the FA are fitly determined. The basic operations of the proposed HA and the proposed FA have been successfully confirmed through SPICE circuit simulation based on the physical device model of TG-SETs.

  4. Effects of nonmetal doping on electronic structures of NaNbO3 based on hybrid density functional calculation

    Science.gov (United States)

    Shi, Haifeng; Lan, Benyue; Zhang, Chengliang; Ye, Enjia; Nie, Yanguang; Bian, Baoan

    2016-10-01

    The influences of a series of anion doping on the electronic structures of sodium niobate (NaNbO3) have been systematically investigated by density functional theory (DFT) calculations with the hybrid B3LYP functional. As for B(C,P)-doped NaNbO3, the isolated B 2p (C 2p, P 3p) states were formed above the valence band maximum (VBM) of NaNbO3, which were too weak to mix with O 2p states and thus produced band gap narrowing. While the band gap of NaNbO3 was slightly narrowed after F doping. As for S-doped NaNbO3, the S 3p states mixed with O 2p states well and thus reduced the band gap energy. According to the calculation results, we tentatively put forward that S doping would be appropriate for single anion doping NaNbO3, while the B(C,P) elements would be suitable candidates for co-doping NaNbO3.

  5. Characteristics of electron cyclotron resonance plasma formed by lower hybrid current drive grill antenna

    Indian Academy of Sciences (India)

    P K Sharma; S L Rao; K Mishra; R G Trivedi; D Bora

    2008-03-01

    A 3.7 GHz system, which is meant for LHCD experiments on ADITYA tokamak, is used for producing ECR discharge. The ECR discharge is produced by setting the appropriate resonance magnetic field of 0.13 T, with hydrogen at a fill pressure of about 5 × 10-5 Torr. The RF powe r, up to 10 kW (of which ∼ 50% is reflected back), with a typical pulse length of 50 ms, is injected into the vacuum chamber of the ADITYA tokamak by a LHCD grill antenna and is used for plasma formation. The average coupled RF power density (the RF power/a typical volume of the plasma) is estimated to be ∼ 5 kW/m3. When the ECR appears inside the tokamak chamber for the given pumping frequency ( = 3.7 GHz) a plasma with a density () ∼ 4 × 1016 m-3 and electron temperature ∼ 8 eV is produced. The density and temperature during the RF pulse are measured by sets of Langmuir probes, located toroidally, on either side of the antenna. signals are also monitored to detect ionization. An estimate of density and temperature based on simple theoretical calculation agrees well with our experimental measurements. The plasma produced by the above mechanism is further used to characterize the ECR-assisted low voltage Ohmic start-up discharges. During this part of the experiments, Ohmic plasma is formed using capacitor banks. The plasma loop voltage is gradually decreased, till the discharge ceases to form. The same is repeated in the presence of ECR-formed plasma (RF pre-ionization), formed 10 ms prior to the loop voltage. We have observed that (with LHCD-induced) ECR-assisted Ohmic start-up discharges is reliably and repeatedly obtained with reduced loop voltage requirement and breakdown time decreases substantially. The current ramp-up rates also decrease with reduced loop voltage operation. These studies established that ECR plasma formed with LHCD system exhibits similar characteristics as reported earlier by dedicated ECR systems. This experiment also addresses the issue of whether ECR plasma

  6. Void denuded zone formation for Fe–15Cr–15Ni steel and PNC316 stainless steel under neutron and electron irradiations

    Energy Technology Data Exchange (ETDEWEB)

    Sekio, Yoshihiro, E-mail: sekio.yoshihiro@jaea.go.jp [Oarai Research and Development Center, Japan Atomic Energy Agency, Ibaraki 311-1393 (Japan); Yamashita, Shinichiro [Oarai Research and Development Center, Japan Atomic Energy Agency, Ibaraki 311-1393 (Japan); Sakaguchi, Norihito [Center for Advanced Research of Energy Technology, Hokkaido University, Hokkaido 060-0808 (Japan); Takahashi, Heishichiro [Oarai Research and Development Center, Japan Atomic Energy Agency, Ibaraki 311-1393 (Japan); Center for Advanced Research of Energy Technology, Hokkaido University, Hokkaido 060-0808 (Japan)

    2015-03-15

    Highlights: • Austenitic stainless steel developed to improve void swelling was used. • Void denuded zone formed near grain boundary can be affected by vacancy mobility. • Vacancy migration energy was estimated from void denuded zone width in the steel. - Abstract: Irradiation-induced void denuded zone (VDZ) formation near grain boundaries was studied to clarify the effects of minor alloying elements on vacancy diffusivity during irradiation in practical PNC316 stainless steel developed for nuclear reactor core materials. The test materials were Fe–15Cr–15Ni steel without additives and PNC316 stainless steel; the latter contains minor alloying elements to improve the void swelling resistance. These steels were neutron-irradiated in the experimental fast reactor JOYO at temperatures from 749 K to 775 K and fast neutron doses of 18–103 dpa, and electron irradiation was also carried out using 1 MeV high voltage electron microscopy at temperatures of 723 K and 773 K and doses up to 14.4 dpa. VDZ formation was analyzed by TEM microstructural observation after irradiation by considering radiation-induced segregation near the grain boundaries. VDZs were formed near random grain boundaries with higher misfit angles in both Fe–15Cr–15Ni and PNC316 steels. The VDZ widths in the PNC316 stainless steel were narrower than those for the Fe–15Cr–15Ni steel for all neutron and electron irradiations. The VDZ width analysis implied that the vacancy diffusivity was reduced in PNC316 stainless steel as a result of interaction of vacancies with minor alloying elements.

  7. Organic electronic materials: Recent advances in the dft description of the ground and excited states using tuned range-separated hybrid functionals

    KAUST Repository

    Körzdörfer, Thomas

    2014-11-18

    Density functional theory (DFT) and its time-dependent extension (TD-DFT) are powerful tools enabling the theoretical prediction of the ground- and excited-state properties of organic electronic materials with reasonable accuracy at affordable computational costs. Due to their excellent accuracy-to-numerical-costs ratio, semilocal and global hybrid functionals such as B3LYP have become the workhorse for geometry optimizations and the prediction of vibrational spectra in modern theoretical organic chemistry. Despite the overwhelming success of these out-of-the-box functionals for such applications, the computational treatment of electronic and structural properties that are of particular interest in organic electronic materials sometimes reveals severe and qualitative failures of such functionals. Important examples include the overestimation of conjugation, torsional barriers, and electronic coupling as well as the underestimation of bond-length alternations or excited-state energies in low-band-gap polymers.In this Account, we highlight how these failures can be traced back to the delocalization error inherent to semilocal and global hybrid functionals, which leads to the spurious delocalization of electron densities and an overestimation of conjugation. The delocalization error for systems and functionals of interest can be quantified by allowing for fractional occupation of the highest occupied molecular orbital. It can be minimized by using long-range corrected hybrid functionals and a nonempirical tuning procedure for the range-separation parameter.We then review the benefits and drawbacks of using tuned long-range corrected hybrid functionals for the description of the ground and excited states of π-conjugated systems. In particular, we show that this approach provides for robust and efficient means of characterizing the electronic couplings in organic mixed-valence systems, for the calculation of accurate torsional barriers at the polymer limit, and for the

  8. Synthesis, and crystal and electronic structure of sodium metal phosphate for use as a hybrid capacitor in non-aqueous electrolyte.

    Science.gov (United States)

    Sundaram, Manickam Minakshi; Watcharatharapong, Teeraphat; Chakraborty, Sudip; Ahuja, Rajeev; Duraisamy, Shanmughasundaram; Rao, Penki Tirupathi; Munichandraiah, Nookala

    2015-12-14

    Energy storage devices based on sodium have been considered as an alternative to traditional lithium based systems because of the natural abundance, cost effectiveness and low environmental impact of sodium. Their synthesis, and crystal and electronic properties have been discussed, because of the importance of electronic conductivity in supercapacitors for high rate applications. The density of states of a mixed sodium transition metal phosphate (maricite, NaMn(1/3)Co(1/3)Ni(1/3)PO4) has been determined with the ab initio generalized gradient approximation (GGA)+Hubbard term (U) method. The computed results for the mixed maricite are compared with the band gap of the parent NaFePO4 and the electrochemical experimental results are in good agreement. A mixed sodium transition metal phosphate served as an active electrode material for a hybrid supercapacitor. The hybrid device (maricite versus carbon) in a non-aqueous electrolyte shows redox peaks in the cyclic voltammograms and asymmetric profiles in the charge-discharge curves while exhibiting a specific capacitance of 40 F g(-1) and these processes are found to be quasi-reversible. After long term cycling, the device exhibits excellent capacity retention (95%) and coulombic efficiency (92%). The presence of carbon and the nanocomposite morphology, identified through X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) studies, ensures the high rate capability while offering possibilities to develop new cathode materials for sodium hybrid devices.

  9. Direct spectroscopic evidence of ultrafast electron transfer from a low band gap polymer to CdSe quantum dots in hybrid photovoltaic thin films.

    Science.gov (United States)

    Couderc, Elsa; Greaney, Matthew J; Brutchey, Richard L; Bradforth, Stephen E

    2013-12-11

    Ultrafast transient absorption spectroscopy is used to study charge transfer dynamics in hybrid films composed of the low band gap polymer PCPDTBT and CdSe quantum dots capped with tert-butylthiol ligands. By selectively exciting the polymer, a spectral signature for electrons on the quantum dots appears on ultrafast time scales (≲ 65 fs), which indicates ultrafast electron transfer. From this time scale, the coupling between the polymer chains and the quantum dots is estimated to be J ≳ 17 meV. The reduced quantum dot acceptors exhibit an unambiguous spectral bleach signature, whose amplitude allows for the first direct calculation of the absolute electron transfer yield in a hybrid solar cell (82 ± 5%). We also show that a limitation of the hybrid system is rapid and measurable geminate recombination due to the small separation of the initial charge pair. The fast recombination is consistent with the internal quantum efficiency of the corresponding solar cell. We therefore have identified and quantified a main loss mechanism in this type of third generation solar cell.

  10. FY1995 study of electronic coservice project which used Optical-Smart Hybrid Card; 1995 nendo hikari IC hybrid card wo mochiite katei kara ukeru gyosei denshika service project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    As one of advanced multi media service, We can think about electoronization-network changing of the public coservice. that the official system provides. It can be expected to improve the life environment for a nation by the electronization. The purpose of this research is to clarify the off-line administration of an individual information and the issue on security. We constructed the experimental system using the Internet and Optical-IC hybrid card that an individual information is administrated. The system provides the following services. (1) On-stop moving service (2) Electronic certificate publishing service (3) Electronic ticket publishing service We have mounted client terminals at Fuchu city hall, Yokohama city hall, and Keio University, and made field experimentation. (NEDO)

  11. Kinetic Cascade in Solar-wind Turbulence: 3D3V Hybrid-kinetic Simulations with Electron Inertia

    Science.gov (United States)

    Cerri, Silvio Sergio; Servidio, Sergio; Califano, Francesco

    2017-09-01

    Understanding the nature of the turbulent fluctuations below the ion gyroradius in solar-wind (SW) turbulence is a great challenge. Recent studies have been mostly in favor of kinetic Alfvén wave (KAW)-type fluctuations, but other kinds of fluctuations with characteristics typical of magnetosonic, whistler, and ion-Bernstein modes could also play a role depending on the plasma parameters. Here, we investigate the properties of the subproton-scale cascade with high-resolution hybrid-kinetic simulations of freely decaying turbulence in 3D3V phase space, including electron inertia effects. Two proton plasma beta are explored: the “intermediate” β p = 1 and “low” β p = 0.2 regimes, both typically observed in the SW and corona. The magnetic energy spectum exhibits {k}\\perp -8/3 and {k}\\parallel -7/2 power laws at β p = 1, while they are slightly steeper at β p = 0.2. Nevertheless, both regimes develop a spectral anisotropy consistent with {k}\\parallel ∼ {k}\\perp 2/3 at {k}\\perp {ρ }p> 1 and pronounced small-scale intermittency. In this context, we find that the kinetic-scale cascade is dominated by KAW-like fluctuations at β p = 1, whereas the low-β case presents a more complex scenario suggesting the simultaneous presence of different types of fluctuations. In both regimes, however, a possible role of the ion-Bernstein-type fluctuations at the smallest scales cannot be excluded.

  12. Electronic structures and phonon free energies of LaCoO3 using hybrid-exchange density functional theory

    Science.gov (United States)

    Mukhopadhyay, S.; Finnis, M. W.; Harrison, N. M.

    2013-03-01

    Hybrid-exchange density functional theory has been used to model the electronic structure of LaCoO3. Based on a rhombohedral unit cell of R3¯c symmetry containing two Co atoms we find a mixed spin phase, comprising alternating low and high spin Co+3 ions, with a total energy at 0 K just 57 meV per formula unit above that of a nonmagnetic semiconducting ground state. In the mixed spin phase the high-spin Co+3 ions have spin moments of 3.1μB and the state is insulating with a band gap of 2.2 eV. Our calculations suggest that the effective on-site Coulomb repulsion energy Ueff on Co+3 ions is spin dependent. The Ueff on Co+3 ions is 7.1 eV and 8.5 eV for the nonmagnetic ground state and for the magnetic high spin state, respectively. For the mixed spin state, two different Ueff are estimated for two Co+3 ions in the unit cell having different spin states, 8.0 eV for the high-spin Co+3 ion and 7.0 eV for the low-spin Co+3 ion. An estimate of the harmonic phonon free energy suggests that this mixed spin phase would become the more stable phase as the temperature increases, which is consistent with experimental evidence. An alternative intermediate spin state is higher in energy at all temperatures.

  13. The electronic structure of organic-inorganic hybrid compounds : (NH4)(2)CuCl4, (CH3NH3)(2)CuCl4 and (C2H5NH3)(2)CuCl4

    NARCIS (Netherlands)

    Zolfaghari, P.; de Wijs, G. A.; de Groot, R. A.

    2013-01-01

    Hybrid organic-inorganic compounds are an intriguing class of materials that have been experimentally studied over the past few years because of a potential broad range of applications. The electronic and magnetic properties of three organic-inorganic hybrid compounds with compositions (NH4)(2)CuCl4

  14. The electronic structure of organic-inorganic hybrid compounds : (NH4)(2)CuCl4, (CH3NH3)(2)CuCl4 and (C2H5NH3)(2)CuCl4

    NARCIS (Netherlands)

    Zolfaghari, P.; de Wijs, G. A.; de Groot, R. A.

    2013-01-01

    Hybrid organic-inorganic compounds are an intriguing class of materials that have been experimentally studied over the past few years because of a potential broad range of applications. The electronic and magnetic properties of three organic-inorganic hybrid compounds with compositions

  15. X-ray holographic microscopy with zone plates applied to biological samples in the water window using 3rd harmonic radiation from the free-electron laser FLASH.

    Science.gov (United States)

    Gorniak, T; Heine, R; Mancuso, A P; Staier, F; Christophis, C; Pettitt, M E; Sakdinawat, A; Treusch, R; Guerassimova, N; Feldhaus, J; Gutt, C; Grübel, G; Eisebitt, S; Beyer, A; Gölzhäuser, A; Weckert, E; Grunze, M; Vartanyants, I A; Rosenhahn, A

    2011-06-06

    The imaging of hydrated biological samples - especially in the energy window of 284-540 eV, where water does not obscure the signal of soft organic matter and biologically relevant elements - is of tremendous interest for life sciences. Free-electron lasers can provide highly intense and coherent pulses, which allow single pulse imaging to overcome resolution limits set by radiation damage. One current challenge is to match both the desired energy and the intensity of the light source. We present the first images of dehydrated biological material acquired with 3rd harmonic radiation from FLASH by digital in-line zone plate holography as one step towards the vision of imaging hydrated biological material with photons in the water window. We also demonstrate the first application of ultrathin molecular sheets as suitable substrates for future free-electron laser experiments with biological samples in the form of a rat fibroblast cell and marine biofouling bacteria Cobetia marina.

  16. Symbolic Algorithmic Analysis of Rectangular Hybrid Systems

    Institute of Scientific and Technical Information of China (English)

    Hai-Bin Zhang; Zhen-Hua Duan

    2009-01-01

    This paper investigates symbolic algorithmic analysis of rectangular hybrid systems. To deal with the symbolic reachability problem, a restricted constraint system called hybrid zone is formalized for the representation and manipulation of rectangular automata state-spaces. Hybrid zones are proved to be closed over symbolic reachability operations of rectangular hybrid systems. They are also applied to model-checking procedures for verifying some important classes of timed computation tree logic formulas. To represent hybrid zones, a data structure called difference constraint matrix is defined.These enable us to deal with the symbolic algorithmic analysis of rectangular hybrid systems in an efficient way.

  17. Effect of Rashba and Dresselhaus Spin-Orbit Couplings on Electron Spin Polarization in a Hybrid Magnetic-Electric Barrier Nanostructure

    Science.gov (United States)

    Yang, Shi-Peng; Lu, Mao-Wang; Huang, Xin-Hong; Tang, Qiang; Zhou, Yong-Long

    2017-04-01

    A theoretical study has been carried out on the spin-dependent electron transport in a hybrid magnetic-electric barrier nanostructure with both Rashba and Dresselhaus spin-orbit couplings, which can be experimentally realized by depositing a ferromagnetic strip and a Schottky metal strip on top of a semiconductor heterostructure. The spin-orbit coupling-dependent transmission coefficient, conductance, and spin polarization are calculated by solving the Schrödinger equation exactly with the help of the transfer-matrix method. We find that both the magnitude and sign of the electron spin polarization vary strongly with the spin-orbit coupling strength. Thus, the degree of electron spin polarization can be manipulated by properly adjusting the spin-orbit coupling strength, and such a nanosystem can be employed as a controllable spin filter for spintronics applications.

  18. Design Features of a Planar Hybrid/Permanent Magnet Strong Focusing Undulator for Free Electron Laser (FEL) And Synchrotron Radiation (SR) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tatchyn, Roman; /SLAC

    2011-09-09

    Insertion devices for Angstrom-wavelength Free Electron Laser (FEL) amplifiers driven by multi-GeV electron beams generally require distributed focusing substantially stronger than their own natural focusing fields. Over the last several years a wide variety of focusing schemes and configurations have been proposed for undulators of this class, ranging from conventional current-driven quadrupoles external to the undulator magnets to permanent magnet (PM) lattices inserted into the insertion device gap. In this paper we present design studies of a flexible high-field hybrid/PM undulator with strong superimposed planar PM focusing proposed for a 1.5 Angstrom Linac Coherent Light Source (LCLS) driven by an electron beam with a 1 mm-mr normalized emittance. Attainable field parameters, tuning modes, and potential applications of the proposed structure are discussed.

  19. A Novel Hybrid Ultramicrotomy/FIB-SEM Technique: Preparation of Serial Electron-Transparent Thin Sections of a Hayabusa Grain

    Science.gov (United States)

    Berger, Eve L.; Keller, Lindsay P.

    2014-01-01

    The Japanese space agency's (JAXA) Hayabusa mission returned the first particulate samples (typically SEM). Using a diamond trim knife, the epoxy surrounding the grain is removed on 3 sides (to within a few microns of the grain); the depth of material removed extends well below the bottom of the particle. The sample is attached to an SEM pin mount, the epoxy coated with conductive paint, and the entire assembly coated with approx. 40nm of carbon to eliminate sample charging during FIB work. A protective carbon cap is placed according to the plan for the 15 FIB sections. The central 'spine' of the cap runs perpendicular to the front of the sample, and the 'ribs' protruding from either side run parallel. Each rib indicates the location of a planned FIB section, and the spine contains the final two planned sections. We use a cap with a 4 micron-wide spine and 2micron-wide ribs that have ?3.5 micron of space between them (narrower cuts result in too much re-deposition of material inside the trenches). Using a 30kV, 3nA ion-beam we expose the front surface of the grain and commence milling trenches between sections. Rather than using the typical C-cut to prepare the sample for lift-out, an L-cut is used instead, leaving the sample connected by an interior tab. tab. Sections are lifted out, attached to TEM grids and thinned to electron transparency. TEM analyses show that our hybrid technique preserves both interior and edge features, including surface modifications from exposure to the space environment, such as damaged rims that form in response to solar wind implantation effects and adhering grains. In addition, the FIB sections provide larger areas that are free of fractures and chatter effects in comparison to the microtome thin sections, thus enabling more accurate measurements of solar flare particle track densities that are used to determine the surface exposure age of the particles.

  20. A Comparative Analysis of Different Finishing and Polishing Devices on Nanofilled, Microfilled, and Hybrid Composite: A Scanning Electron Microscopy and Profilometric Study

    Science.gov (United States)

    Yadav, Rishi D; Raisingani, Deepak; Mathur, Rachit

    2016-01-01

    The continuous development of esthetically acceptable adhesive restorative material has made a variety of tooth-colored materials available for clinical use. The advent of visible light polymerizing resin and the use of finer filler particles permit resin composites to be polished to higher degree. The effect of polishing systems on surface finish has been reported to be material-dependent, and the effectiveness of these systems was mostly product-dependent. Hence, the purpose of this study was to evaluate the efficiency of finishing and polishing systems on the surface roughness of nanofilled, microfilled, and hybrid composite restorative materials available in the market. How to cite this article Yadav RD, Raisingani D, Jindal D, Mathur R. A Comparative Analysis of Different Finishing and Polishing Devices on Nanofilled, Microfilled, and Hybrid Composite: A Scanning Electron Microscopy and Profilometric Study. Int J Clin Pediatr Dent 2016;9(3):201-208. PMID:27843250

  1. Self-consistent kinetic simulations of lower hybrid drift instability resulting in electron current driven by fusion products in tokamak plasmas

    CERN Document Server

    Cook, J W S; Dendy, R O

    2010-01-01

    We present particle-in-cell (PIC) simulations of minority energetic protons in deuterium plasmas, which demonstrate a collective instability responsible for emission near the lower hybrid frequency and its harmonics. The simulations capture the lower hybrid drift instability in a regime relevant to tokamak fusion plasmas, and show further that the excited electromagnetic fields collectively and collisionlessly couple free energy from the protons to directed electron motion. This results in an asymmetric tail antiparallel to the magnetic field. We focus on obliquely propagating modes under conditions approximating the outer mid-plane edge in a large tokamak, through which there pass confined centrally born fusion products on banana orbits that have large radial excursions. A fully self-consistent electromagnetic relativistic PIC code representing all vector field quantities and particle velocities in three dimensions as functions of a single spatial dimension is used to model this situation, by evolving the in...

  2. Hybridization of the marine seaweeds, Fucus serratus and Fucus evanescens (Heterokontophyta : Phaeophyceae) in a 100-year-old zone of secondary contact

    NARCIS (Netherlands)

    Coyer, JA; Hoarau, G; Stam, WT; Olsen, JL

    2002-01-01

    Historically, the intertidal seaweeds Fucus serratus (Fs) and Fucus evanescens (Fe) were sympatric only along the western coast of Norway. In the mid-1890s, Fe (monoecious) was accidentally introduced into the Oslofjord. Putative hybridization with the endemic Fs (dioecious) was observed in Oslofjor

  3. Bipolar resistive switching properties of Ti-CuO/(hexafluoro-hexa-peri-hexabenzocoronene)-Cu hybrid interface device: Influence of electronic nature of organic layer

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Bharti; Mehta, B. R.; Varandani, Deepak [Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 (India); Govind [Surface Physics Group, National Physical Laboratory (CSIR), New Delhi-110012 (India); Narita, A.; Feng, X.; Muellen, K. [Max-Planck Institute for Polymer Research, D-55128 Mainz (Germany)

    2013-05-28

    This study reports the change in the structural and junction properties of Ti-CuO-Cu structure on incorporation of a 2-dimensional (2D) organic layer comprising of n-type hexafluoro-hexa-peri-hexabenzocoronene (6F-HBC). A bipolar resistive switching is observed in the device having interface between sputter deposited copper oxide (CuO) and vacuum sublimated 6F-HBC hybrid interface. The CuO/6F-HBC hybrid interface exhibits rectifying I-V characteristics in complete contrast to the ohmic and rectifying characteristics of junctions based on individual 6F-HBC and CuO layers. Large change in resistive switching property from unipolar resistive switching in CuO/HBC to bipolar resistive switching in CuO/6F-HBC interface was observed. At the CuO/6F-HBC interface, C1s peak corresponding to fluorinated carbon is shifted by 0.68 eV towards higher binding energy (BE) side and O1s peak due to non-lattice oxygen is shifted by 0.6 eV towards lower BE, confirming the interaction of O{sup 2-} ion in CuO with fluorinated carbon atoms in 6F-HBC at the hybrid interface. Correlation between conductive atomic force microscopy images and atomic force microscopy topography images, I-V characteristics in conducting, non-conducting, and pristine regions along with x-ray photoelectron spectroscopy results establishes the important role of hybrid interface to determining the resistive switching properties. This study demonstrates that the resistive switching and interface properties of a hybrid device based on inorganic and organic 2D materials can be modified by changing the electronic properties of organic layer by attaching suitable functional groups.

  4. Electron-impact excitation of the singlet states of N2. I - The Birge-Hopfield system /b 1 pi u - X 1 Sigma g +/. [in auroral zones

    Science.gov (United States)

    Zipf, E. C.; Gorman, M. R.

    1980-01-01

    Results of a study of the electron-impact excitation of the b 1 pi u state of N2, one of the singlet states thought to be excited by precipitating electrons in the auroral zones, and of its predissociation and radiative relaxation through the emission of the Birge-Hopfield band system (b 1 pi u - X 1 Sigma g +) are presented. A collimated electron beam was passed through N2 gas producing a variety of atomic states through dissociative excitation, and the radiation resulting from relaxation of these states was observed by VUV and visible-IR monochromators. Absolute emission cross sections for 11 Birge-Hopfield bands are obtained for energies from threshold to 500 eV, and used to calculate the absolute transition probabilities for BH(1, v-prime) bands and the variation of the electric dipole moment with internuclear distance. With the exception of the v-prime equals 1, 5 and 6 vibrational levels, all b 1 pi u levels are found to predissociate with a specific predissociation branching ratio greater than 0.99, representing a major source of nitrogen atoms.

  5. Improving the Mechanical Properties of the Fusion Zone in Electron-Beam Welded Ti-5Al-5Mo-5V-3Cr Alloys

    Science.gov (United States)

    Marvel, Christopher J.; Sabol, Joseph C.; Pasang, Timotius; Watanabe, Masashi; Misiolek, Wojciech Z.

    2017-01-01

    It is well-known that ω-phase precipitates embrittle Ti-5553 alloys and that ω-phase embrittlement can be overcome with appropriate heat treatments. However, the microstructural evolution of electron-beam welded Ti-5553 is not as understood as compared to the cast or wrought material. This study compared the microstructures of as-welded and post-weld heat-treated specimens by scanning and transmission electron microscopy, and similarly compared the localized mechanical behavior of the fusion zones with microhardness testing and digital image correlation coupled tensile testing. The primary observations were that the embrittling ω-phase precipitates formed upon cooling, and could not be fully solutionized in a single-step treatment of 1077 K (804 °C) for 1 hour. It was also discovered that nanoscale α-phase precipitates nucleated after the single-step treatment, although they were small in number and sparsely distributed. However, a two-step heat treatment of 1077 K (804 °C) for 1 hour and 873 K (600 °C) for 4 hours completely solutionized the ω-phase and produced a dense network of 2-μm-wide α-phase plates, which significantly improved the mechanical properties. Overall, this study has shown that post-weld heat treatments improve the strength and ductility of electron-beam welded Ti-5553 alloys by controlling ω- and α-phase evolution.

  6. Improving the Mechanical Properties of the Fusion Zone in Electron-Beam Welded Ti-5Al-5Mo-5V-3Cr Alloys

    Science.gov (United States)

    Marvel, Christopher J.; Sabol, Joseph C.; Pasang, Timotius; Watanabe, Masashi; Misiolek, Wojciech Z.

    2017-04-01

    It is well-known that ω-phase precipitates embrittle Ti-5553 alloys and that ω-phase embrittlement can be overcome with appropriate heat treatments. However, the microstructural evolution of electron-beam welded Ti-5553 is not as understood as compared to the cast or wrought material. This study compared the microstructures of as-welded and post-weld heat-treated specimens by scanning and transmission electron microscopy, and similarly compared the localized mechanical behavior of the fusion zones with microhardness testing and digital image correlation coupled tensile testing. The primary observations were that the embrittling ω-phase precipitates formed upon cooling, and could not be fully solutionized in a single-step treatment of 1077 K (804 °C) for 1 hour. It was also discovered that nanoscale α-phase precipitates nucleated after the single-step treatment, although they were small in number and sparsely distributed. However, a two-step heat treatment of 1077 K (804 °C) for 1 hour and 873 K (600 °C) for 4 hours completely solutionized the ω-phase and produced a dense network of 2- μm-wide α-phase plates, which significantly improved the mechanical properties. Overall, this study has shown that post-weld heat treatments improve the strength and ductility of electron-beam welded Ti-5553 alloys by controlling ω- and α-phase evolution.

  7. Electronic structure in a one-Fe Brillouin zone of the iron pnictide superconductors CsFe2As2 and RbFe2As2

    Science.gov (United States)

    Kong, S.; Liu, D. Y.; Cui, S. T.; Ju, S. L.; Wang, A. F.; Luo, X. G.; Zou, L. J.; Chen, X. H.; Zhang, G. B.; Sun, Z.

    2015-11-01

    Using angle-resolved photoemission spectroscopy, we studied the electronic structures of CsFe2As2 and RbFe2As2 . Contrary to other iron-based superconductors where the band structures are usually depicted in the two-Fe Brillouin zone (BZ), we found that the distribution of electronic spectral weight in CsFe2As2 and RbFe2As2 follows the one-Fe BZ, and that the emerging band structure is qualitatively consistent with theoretical band calculations of the one-Fe BZ except for some shadow band effect. Our data suggest that the interlayer separation is an important tuning factor for the physics of FeAs layers, the increase of which can reduce the coupling between Fe and As and lead to the emergence of the electronic structure in accord with the one-Fe symmetry of the Fe square lattice. Our finding puts strong constraints on the theoretical models constructed on the basis of the one-Fe BZ.

  8. Particle-in-cell simulations of an alpha channeling scenario: electron current drive arising from lower hybrid drift instability of fusion-born ions

    Science.gov (United States)

    Cook, James; Chapman, Sandra; Dendy, Richard

    2010-11-01

    Particle-in-cell (PIC) simulations of fusion-born protons in deuterium plasmas demonstrate a key alpha channeling phenomenon for tokamak fusion plasmas. We focus on obliquely propagating modes at the plasma edge, excited by centrally born fusion products on banana orbits, known to be responsible for observations of ion cyclotron emission in JET and TFTR. A fully self-consistent electromagnetic 1D3V PIC code evolves a ring-beam distribution of 3MeV protons in a 10keV thermal deuterium-electron plasma with realistic mass ratio. A collective instability occurs, giving rise to electromagnetic field activity in the lower hybrid range of frequencies. Waves spontaneously excited by this lower hybrid drift instability undergo Landau damping on resonant electrons, drawing out an asymmetric tail in the distribution of electron parallel velocities, which constitutes a net current. These simulations demonstrate a key building block of some alpha channeling scenarios: the direct collisionless coupling of fusion product energy into a form which can help sustain the equilibrium of the tokamak.

  9. Note: Easy-to-maintain electron cyclotron resonance (ECR) plasma sputtering apparatus featuring hybrid waveguide and coaxial cables for microwave delivery.

    Science.gov (United States)

    Akazawa, Housei

    2016-06-01

    The branched-waveguide electron cyclotron resonance plasma sputtering apparatus places quartz windows for transmitting microwaves into the plasma source not in the line of sight of the target. However, the quartz windows must be replaced after some time of operation. For maintenance, the loop waveguide branching from the T-junction must be dismounted and re-assembled accurately, which is a time-consuming job. We investigated substituting the waveguide branches with two sets of coaxial cables and waveguide/coaxial cable converters to simplify assembly as far as connection and disconnection go. The resulting hybrid system worked well for the purposes of plasma generation and film deposition.

  10. Comparison between rad-hard standard float zone (FZ) and magnetic Czochralski (MCZ) silicon diodes in radiotherapy electron beam dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Santos, T.C. dos; Goncalves, J.A.C.; Vasques, M.M.; Tobias, C.C.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes; Neves-Junior, W.F.P.; Haddad, C.M.K. [Hospital Sirio Libanes, Sao Paulo, SP (Brazil). Sociedade Beneficente de Senhoras; Harkonen, J. [Helsinki University of Technology (Denmark). Helsinki Inst. of Physics

    2010-07-01

    Full text. The use of semiconductor detectors has increased in radiotherapy practice since 1980s due to mainly their fast processing time, small sensitive volume and high relative sensitivity to ionizing radiation. Other major advantages of Si devices are excellent repeatability, good mechanical stability, high spatial resolution and the energy independence of mass collision stopping powers ratios (between silicon and water for electron beams with energy from 4 up to 20 MeV). However, ordinary silicon devices are very prone to radiation damage effects. In the last years, the development of radiation tolerant silicon detectors for High Energy Physics experiments has overcome this drawback. In this work we present the preliminary results obtained with a rad-hard epitaxial silicon diode as on-line clinical electron beam dosimeter. The diodes with 25 mm{sup 2} active area, were housed in a PMMA probe and connected, in a photovoltaic mode, to a Keithley 6517B electrometer. During all measurements, the diodes were held between PMMA plates, placed at Zref and centered in a radiation field of 10 cm x 10 cm, with the SSD kept at 100 cm. The devices dosimetric response was evaluated for 6, 9, 12, 15, 18 e 21 MeV electron beams from a Siemens KD 2 Radiotherapy Linear Accelerator, located at Sirio-Libanes Hospital. The radiation induced current in the diodes was registered as a function of the exposure time during 60 s for a fixed 300 MU. To study the short term repeatability, current signals were registered for the same radiation dose, for all energies. The dose-response of the diodes was achieved through the integration of the current signals as a function of the exposure time. The results obtained in the energy range of 6 up to 21 MeV evidenced that, for the same average dose rate of 5.0 cGy/s, the current signals are very stable and repeatable in both cases. For all energies, data shows good instantaneous repeatability with a percentage variation coefficient better than 2

  11. Traffic sounds and cycling safety : the use of electronic devices by cyclists and the quietness of hybrid and electric cars.

    NARCIS (Netherlands)

    Stelling-Konczak, A. Hagenzieker, M.P. & Wee, B. van

    2015-01-01

    The growing popularity of electric devices and the increasing number of hybrid and electric cars have recently raised concerns about the use of auditory signals by vulnerable road users. This paper consolidates current knowledge about the two trends in relation to cycling safety. Both a literature r

  12. Traffic sounds and cycling safety : the use of electronic devices by cyclists and the quietness of hybrid and electric cars.

    NARCIS (Netherlands)

    Stelling-Konczak, A. Hagenzieker, M.P. & Wee, B. van

    2015-01-01

    The growing popularity of electric devices and the increasing number of hybrid and electric cars have recently raised concerns about the use of auditory signals by vulnerable road users. This paper consolidates current knowledge about the two trends in relation to cycling safety. Both a literature

  13. Synthesis of and evidence for electronic communication within heteromultimetallic Tetrakis(NCN-pincer metal) - (Metallo)porphyrin Hybrids

    NARCIS (Netherlands)

    Suijkerbuijk, B.M.J.M.; Tooke, D.M.; Lutz, M.|info:eu-repo/dai/nl/304828971; Spek, A.L.|info:eu-repo/dai/nl/156517566; Jenneskens, L.W.|info:eu-repo/dai/nl/071635246; van Koten, G.|info:eu-repo/dai/nl/073839191; Klein Gebbink, R.J.M.|info:eu-repo/dai/nl/166032646

    2010-01-01

    Several heteromultimetallic pincer-porphyrin hybrids have been prepared in excellent yields by stepwise metalation of a general precursor, [2H(Br(NCN))4], which was designed in such a way so as to guarantee selectivity for either the porphyrin or pincer sites during themetalation steps. First, ameta

  14. The Digital electronic Guideline Library (DeGeL): a hybrid framework for representation and use of clinical guidelines.

    Science.gov (United States)

    Shahar, Yuval; Young, Ohad; Shalom, Erez; Mayaffit, Alon; Moskovitch, Robert; Hessing, Alon; Galperin, Maya

    2004-01-01

    We propose to present a poster (and potentially also a demonstration of the implemented system) summarizing the current state of our work on a hybrid, multiple-format representation of clinical guidelines that facilitates conversion of guidelines from free text to a formal representation. We describe a distributed Web-based architecture (DeGeL) and a set of tools using the hybrid representation. The tools enable performing tasks such as guideline specification, semantic markup, search, retrieval, visualization, eligibility determination, runtime application and retrospective quality assessment. The representation includes four parallel formats: Free text (one or more original sources); semistructured text (labeled by the target guideline-ontology semantic labels); semiformal text (which includes some control specification); and a formal, machine-executable representation. The specification, indexing, search, retrieval, and browsing tools are essentially independent of the ontology chosen for guideline representation, but editing the semi-formal and formal formats requires ontology-specific tools, which we have developed in the case of the Asbru guideline-specification language. The four formats support increasingly sophisticated computational tasks. The hybrid guidelines are stored in a Web-based library. All tools, such as for runtime guideline application or retrospective quality assessment, are designed to operate on all representations. We demonstrate the hybrid framework by providing examples from the semantic markup and search tools.

  15. Improved photochromic properties on viologen-based inorganic-organic hybrids by using π-conjugated substituents as electron donors and stabilizers.

    Science.gov (United States)

    Lin, Rong-Guang; Xu, Gang; Wang, Ming-Sheng; Lu, Gang; Li, Pei-Xin; Guo, Guo-Cong

    2013-02-04

    A series of inorganic-organic hybrid compounds L(2)(Bi(2)Cl(10)) (L = HMV(2+) = N-proton-N'-methyl-4,4'-bipyridinium for 1, L = HBzV(2+) = N-proton-N'-benzyl-4,4'-bipyridinium for 2, and L = HPeV(2+) = N-proton-N'-phenethyl-4,4'-bipyridinium for 3) have been successfully synthesized by an in situ solvothermal reaction. Compounds 1-3, with the same metal halide as anions but different asymmetric viologen molecules as cations, are ideal model compounds for investigating the detailed effect of different photochromically active molecules on the photochromic properties of the hybrids. Compound 1 shows no photochromic behavior, but compounds 2 and 3 possess photochromism and show a faster photoresponse rate than other reported viologen metal halide hybrids. Studies on the relationship between the structure and photochromic behavior clearly reveal that π-conjugated substituents could be used to improve the photoresponsibility and enrich the developed color efficiently and that the π···π interaction among organic components may not only be a powerful factor to stabilize the viologen monocation radical but also act as the second path of electron transfer from the π-conjugated substituent to the viologen cation for the photochromic process, which significantly influences the photochromic properties.

  16. First-principles hybrid functional study of the electronic structure and charge carrier mobility in perovskite CH3NH3SnI3

    Science.gov (United States)

    Wu, Li-Juan; Zhao, Yu-Qing; Chen, Chang-Wen; Wang, Lin-Zhi; Liu, Biao; Cai, Meng-Qiu

    2016-10-01

    We calculate the electronic properties and carrier mobility of perovskite CH3NH3SnI3 as a solar cell absorber by using the hybrid functional method. The calculated result shows that the electron and hole mobilities have anisotropies with a large magnitude of 1.4 × 104 cm2·V-1·s-1 along the y direction. In view of the huge difference between hole and electron mobilities, the perovskite CH3NH3SnI3 can be considered as a p-type semiconductor. We also discover a relationship between the effective mass anisotropy and electronic occupation anisotropy. The above results can provide reliable guidance for its experimental applications in electronics and optoelectronics. Project supported by the National Natural Science Foundation of China (Grant No. 51172067), the Hunan Provincial Natural Science Fund for Distinguished Young Scholars, China (Grant No. 13JJ1013), the Specialized Research Fund for the Doctoral Program of Higher Education, China (Grant No. 20130161110036), and the New Century Excellent Talents in University, China (Grant No. NCET-12-0171.D).

  17. Nonlinear electronic excitations in crystalline solids using meta-generalized gradient approximation and hybrid functional in time-dependent density functional theory

    Science.gov (United States)

    Sato, Shunsuke A.; Taniguchi, Yasutaka; Shinohara, Yasushi; Yabana, Kazuhiro

    2015-12-01

    We develop methods to calculate electron dynamics in crystalline solids in real-time time-dependent density functional theory employing exchange-correlation potentials which reproduce band gap energies of dielectrics; a meta-generalized gradient approximation was proposed by Tran and Blaha [Phys. Rev. Lett. 102, 226401 (2009)] (TBm-BJ) and a hybrid functional was proposed by Heyd, Scuseria, and Ernzerhof [J. Chem. Phys. 118, 8207 (2003)] (HSE). In time evolution calculations employing the TB-mBJ potential, we have found it necessary to adopt the predictor-corrector step for a stable time evolution. We have developed a method to evaluate electronic excitation energy without referring to the energy functional which is unknown for the TB-mBJ potential. For the HSE functional, we have developed a method for the operation of the Fock-like term in Fourier space to facilitate efficient use of massive parallel computers equipped with graphic processing units. We compare electronic excitations in silicon and germanium induced by femtosecond laser pulses using the TB-mBJ, HSE, and a simple local density approximation (LDA). At low laser intensities, electronic excitations are found to be sensitive to the band gap energy: they are close to each other using TB-mBJ and HSE and are much smaller in LDA. At high laser intensities close to the damage threshold, electronic excitation energies do not differ much among the three cases.

  18. Nonlinear electronic excitations in crystalline solids using meta-generalized gradient approximation and hybrid functional in time-dependent density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Shunsuke A. [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571 (Japan); Taniguchi, Yasutaka [Center for Computational Science, University of Tsukuba, Tsukuba 305-8571 (Japan); Department of Medical and General Sciences, Nihon Institute of Medical Science, 1276 Shimogawara, Moroyama-Machi, Iruma-Gun, Saitama 350-0435 (Japan); Shinohara, Yasushi [Max Planck Institute of Microstructure Physics, 06120 Halle (Germany); Yabana, Kazuhiro [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba 305-8571 (Japan); Center for Computational Science, University of Tsukuba, Tsukuba 305-8571 (Japan)

    2015-12-14

    We develop methods to calculate electron dynamics in crystalline solids in real-time time-dependent density functional theory employing exchange-correlation potentials which reproduce band gap energies of dielectrics; a meta-generalized gradient approximation was proposed by Tran and Blaha [Phys. Rev. Lett. 102, 226401 (2009)] (TBm-BJ) and a hybrid functional was proposed by Heyd, Scuseria, and Ernzerhof [J. Chem. Phys. 118, 8207 (2003)] (HSE). In time evolution calculations employing the TB-mBJ potential, we have found it necessary to adopt the predictor-corrector step for a stable time evolution. We have developed a method to evaluate electronic excitation energy without referring to the energy functional which is unknown for the TB-mBJ potential. For the HSE functional, we have developed a method for the operation of the Fock-like term in Fourier space to facilitate efficient use of massive parallel computers equipped with graphic processing units. We compare electronic excitations in silicon and germanium induced by femtosecond laser pulses using the TB-mBJ, HSE, and a simple local density approximation (LDA). At low laser intensities, electronic excitations are found to be sensitive to the band gap energy: they are close to each other using TB-mBJ and HSE and are much smaller in LDA. At high laser intensities close to the damage threshold, electronic excitation energies do not differ much among the three cases.

  19. Studies of Total Electron Content variations at low-latitude stations within the Equatorial Ionization Anomaly zone

    Science.gov (United States)

    Lilian, Olatunbosun

    2016-07-01

    The total electron content (TEC) is an important parameter to monitor for possible space weather impacts. The radio waves that pass through the earth's ionosphere travel more slowly than their free space velocity due to group path delay of the ionosphere. This group path delay is directly proportional to the TEC of the ionosphere. Using dual frequency GPS receiver at low latitude stations of Ile-Ife (7.52oN, 4.28oE), Addis Ababa (9.04oN, 38.77oE) and Bangalore (13.03oE, 77.57oE), all located within 0 - 15oN of the equatorial anomaly region, the measurement of ionospheric TEC for 2012 has been carried out. The data from the three stations were used to study the diurnal, monthly and seasonal variations of TEC. The diurnal variations maximize between 10:00 - 16:00UT, 08:00 - 14:00UT and 06:00 - 12:00UT for Ile-Ife, Addis Ababa and Bangalore stations respectively. The diurnal variations showed wave-like pertubation during disturbed and quiet periods at Bangalore and Addis Ababa stations. The monthly average TEC variations showed that the month of March recorded the highest TEC value of ~59TECu at about 16:00UT in Ile-Ife station, while TEC at Addis Ababa and Bangalore maximize in October with ~72TECu and 65TECu at about 11:00UT and 09:00UT respectively. Seasonal variations showed that TEC maximizes during the equinoctial months and least in summer, over the three stations. Keywords: Total Electron Content, Equatorial Ionization Anomaly, Global Positioning System co-author:E.A. Ariyibi(Department of Physics and Engineering Physics, Obafemi Awolowo University, Ile-Ife, Nigeria)

  20. Local zone wise elastic and plastic properties of electron beam welded Ti-6Al-4V alloy using digital image correlation technique: A comparative study between uniform stress and virtual fields method

    Science.gov (United States)

    Saranath, K. M.; Ramji, M.

    2015-05-01

    Joining of materials using welding results in the formation of material zones with varying microstructure across the weld. Extraction of the mechanical properties of those individual heterogeneous zones are important in designing components and structures comprised of welds. In this study, the zone wise local extraction of the elastic and plastic properties of an electron beam welded Ti-6Al-4V titanium alloy has been carried out using both the uniform stress method (USM) and the virtual fields method (VFM) involving digital image correlation (DIC) technique. The surface strain field obtained using DIC technique from a transverse weld specimen tensile testing is used for extracting the zone wise strain evolution. Initially, using uniform stress assumption, zone wise full range stress-strain curves are extracted. In USM methodology, the elastic and plastic material models are fitted to the zone wise stress-strain curves and required parameters are extracted from it. But inherent disadvantage is lot of images need to be processed for the parameter extraction. Recently, VFM is gaining lot of popularity in characterization domain as it is robust, accurate and faster. VFM is based on the principle of virtual work where, the weak form of local equilibrium equations and kinematically admissible virtual displacement fields are utilized for parameter extraction. Hollomon's power law is used here as the hardening rule. Young's modulus, Poisson's ratio, yield stress, strength coefficient and strain hardening exponent are the parameters extracted zone wise using both USM and VFM. A Vicker's microhardness measurement is also conducted across the weld zone towards mapping the strength behavior. Fusion zone has reported higher yield strength, strength coefficient and Poisson's ratio. Young's modulus value is found decreasing from base metal towards the fusion zone. The trend observed in parameter variation across the weld zone obtained by both USM and VFM compares very well. Due

  1. THE MECHANISMS OF THE DEVELOPMENT OF CORN HYBRIDS DEPENDING ON THE TERMS OF PLANTING AND TMTD-PLUS DISINFECTANT IN THE ZONE OF SUFFICIENT MOISTURE OF CENTRAL CISCAUCASIA

    Directory of Open Access Journals (Sweden)

    Kravchenko R. V.

    2015-11-01

    Full Text Available There was given a review of the results of the study in the conditions of sufficient moisture of Central Ciscaucasia, the influence of planting terms and presowing seed treatment by the drug called "TMTDplus", containing Krezatsin growth stimulator in its composition, on the development of corn hybrids of different maturity groups of the selection of Krasnodar Research Institute of Agriculture named after P.P. Lukyanenko (Ross 199, Ross 299, Krasnodar 382 and Krasnodar 410 and the All-Russian Research Institute of Corn (Mashuk 170, Newton, RIC 345 and Eric, as well as middle- maturity population Rossiyskaya 1. The studies were conducted in accordance with the thematic plan of scientific researches of the chair of crop and forage production of the Stavropol State Agrarian University. The soil surface of the experimental station of StavrGAU was presented as leached black soil. The technology of growing of maize on the experimental plot corresponds to the standard one for the present area and cultivar. The predecessor is winter wheat. Sowing was performed in three terms. The first (early sowing term was carried out at t = + 7 ... +8 ° C. The second (recommended - when t = + 10 ... + 12 ° C. The third (later sowing time was carried out at t = +15 ° C. The plant density: early-maturing hybrids – 70 thousand pieces/ha, is mid-maturing ones – 60 thousand pieces/ha, middleripe – 50 thousand piece/ha, middle-later ones – 45 thousand pieces/ha. The scheme is single-row, with spacing of 70 cm. The application of the studied drug TMTD-plus helped to reduce the growing season of maize plants for one - four days. Thus, changing the sowing terms of maize hybrids and populations, we can largely control the development of plants changing the length of the growing season to two weeks and form a harvesting conveyor, thereby reducing the intensity of field work

  2. Population genetic structure and mating system in the hybrid zone between Pinus sibirica Du Tour and P. pumila (Pall.) Regel at the Eastern Baikal Lake shore

    OpenAIRE

    E. A. Petrova; S. N. Goroshkevich; Y.S. Belokon; D.V. Politov

    2013-01-01

    Genetic structure of sympatric Pinus sibirica Du Tour and P. pumila (Pall.) Regel populations and putative interspecific hybrids between them was analyzed in the Baikal Lake region (Barguzin Biosphere Natural Reserve, Davsha River basin) by means of 31 allozyme loci controlling 18 enzyme systems. Several alleles at loci Adh-1, Fest-2, Lap-3, Pgi-1, Sod-3 and Skdh-1 were diagnostic for P. sibirica, while alleles typical for P. pumila were detected at loci Gdh, Got-3, Lap-3, Mdh-2, Mdh-4, Pepca...

  3. 3D-hybrid material design with electron/lithium-ion dual-conductivity for high-performance Li-sulfur batteries

    Science.gov (United States)

    Zhao, Yan; Tan, Rui; Yang, Jie; Wang, Kai; Gao, Rongtan; Liu, Dong; Liu, Yidong; Yang, Jinlong; Pan, Feng

    2017-02-01

    We report a novel 3D-hybrid cathode material with three-dimensional (3D) N-GO/CNT framework to load sulfur (77.6 wt %), and sulfonated polyaniline (SPANI) of coating layer. Used as a cathode material, it possesses a high capacity (1196 mAh g-1@0.3 A g-1@1.6 mg cm-2), excellent charging-discharging rate (680 mAh g-1@7.5 A g-1) and long-life performance (maintaining 71.1% capacity over 450 cycles), which is mainly attributed to the benefits of excellent electronic/Li-ionic dual-conductivity and confinement effect of the 3D-hybrid N-GO/CNT framework coated by self-doping conducting polymer SPANI. Thus, a 3D sulfur cathode modified with electronic/Li-ionic dual-conduction network can significantly enhance the electrochemical performance and stability, and this novel type of material is very promising for commercial applications that require high energy and power density, long life, and excellent abuse tolerance.

  4. Fluid and hybrid models for streamers

    Science.gov (United States)

    Bonaventura, Zdeněk

    2016-09-01

    Streamers are contracted ionizing waves with self-generated field enhancement that propagate into a low-ionized medium exposed to high electric field leaving filamentary trails of plasma behind. The widely used model to study streamer dynamics is based on drift-diffusion equations for electrons and ions, assuming local field approximation, coupled with Poisson's equation. For problems where presence of energetic electrons become important a fluid approach needs to be extended by a particle model, accompanied also with Monte Carlo Collision technique, that takes care of motion of these electrons. A combined fluid-particle approach is used to study an influence of surface emission processes on a fast-pulsed dielectric barrier discharge in air at atmospheric pressure. It is found that fluid-only model predicts substantially faster reignition dynamics compared to coupled fluid-particle model. Furthermore, a hybrid model can be created in which the population of electrons is divided in the energy space into two distinct groups: (1) low energy `bulk' electrons that are treated with fluid model, and (2) high energy `beam' electrons, followed as particles. The hybrid model is then capable not only to deal with streamer discharges in laboratory conditions, but also allows us to study electron acceleration in streamer zone of lighting leaders. There, the production of fast electrons from streamers is investigated, since these (runaway) electrons act as seeds for the relativistic runaway electron avalanche (RREA) mechanism, important for high-energy atmospheric physics phenomena. Results suggest that high energy electrons effect the streamer propagation, namely the velocity, the peak electric field, and thus also the production rate of runaway electrons. This work has been supported by the Czech Science Foundation research project 15-04023S.

  5. Characterization of calcium and zinc spatial distributions at the fibrocartilage zone of bone–tendon junction by synchrotron radiation-based micro X-ray fluorescence analysis combined with backscattered electron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hongbin; Chen, Can; Wang, Zhanwen; Qu, Jin; Xu, Daqi [Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha 410008 (China); Wu, Tianding; Cao, Yong [Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha 410008 (China); Zhou, Jingyong; Zheng, Cheng [Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha 410008 (China); Hu, Jianzhong, E-mail: jianzhonghu@hotmail.com [Department of Sports Medicine, Research Center of Sports Medicine, Xiangya Hospital, Central South University, Changsha 410008 (China); Department of Spine Surgery, Xiangya Hospital, Central South University, Changsha 410008 (China)

    2015-09-01

    Tendon attaches to bone through a functionally graded fibrocartilage zone, including uncalcified fibrocartilage (UF), tidemark (TM) and calcified fibrocartilage (CF). This transition zone plays a pivotal role in relaxing load transfer between tendon and bone, and serves as a boundary between otherwise structurally and functionally distinct tissue types. Calcium and zinc are believed to play important roles in the normal growth, mineralization, and repair of the fibrocartilage zone of bone–tendon junction (BTJ). However, spatial distributions of calcium and zinc at the fibrocartilage zone of BTJ and their distribution–function relationship are not totally understood. Thus, synchrotron radiation-based micro X-ray fluorescence analysis (SR-μXRF) in combination with backscattered electron imaging (BEI) was employed to characterize the distributions of calcium and zinc at the fibrocartilage zone of rabbit patella–patellar tendon complex (PPTC). For the first time, the unique distributions of calcium and zinc at the fibrocartilage zone of the PPTC were clearly mapped by this method. The distributions of calcium and zinc at the fibrocartilage zone of the PPTC were inhomogeneous. A significant accumulation of zinc was exhibited in the transition region between UF and CF. The highest zinc content (3.17 times of that of patellar tendon) was found in the TM of fibrocartilage zone. The calcium content began to increase near the TM and increased exponentially across the calcified fibrocartilage region towards the patella. The highest calcium content (43.14 times of that of patellar tendon) was in the transitional zone of calcified fibrocartilage region and the patella, approximately 69 μm from the location with the highest zinc content. This study indicated, for the first time, that there is a differential distribution of calcium and zinc at the fibrocartilage zone of PPTC. These observations reveal new insights into region-dependent changes across the fibrocartilage

  6. Effect of the electric field pattern on the generation of fast electrons in front of lower hybrid launchers

    Energy Technology Data Exchange (ETDEWEB)

    Valade, Laurent, E-mail: laurent.valade@cea.fr; Ekedahl, Annika; Colas, Laurent; Goniche, Marc; Hillairet, Julien [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France); Fuchs, Vladimir; Petrzilka, Vaclav [Institute of Plasma Physics, AS CR, Prague (Czech Republic); Li, Miaohui; Zhang, Bin [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2015-12-10

    The effect of the detailed waveguide spectrum on the electron acceleration has been studied for the 3.7 GHz LHCD launchers in Tore Supra, i.e. the ITER-like passive-active multijunction (PAM) launcher and the fully-active-multijunction (FAM) launcher, using test electron modelling technique. The detailed launched antenna wave spectrum is used as input to the code that computes the dynamics of the electrons in the electric field. Comparison with the LHCD launchers in EAST, operating at 2.45 GHz and 4.6 GHz, has also been made. The simulations show that the PAM-design generates lower flux of fast electrons than FAM-launchers, this could be the consequence of the wider waveguide of PAM-launcher (14.65 mm for Tore-Supra) than FAM-launcher (8 mm for Tore-Supra)

  7. High current density and longtime stable field electron transfer from large-area densely arrayed graphene nanosheet-carbon nanotube hybrids.

    Science.gov (United States)

    Deng, Jian-Hua; Cheng, Lin; Wang, Fan-Jie; Li, Guo-Zheng; Li, De-Jun; Cheng, Guo-An

    2014-12-10

    Achieving high current and longtime stable field emission from large area (larger than 1 mm(2)), densely arrayed emitters is of great importance in applications for vacuum electron sources. We report here the preparation of graphene nanosheet-carbon nanotube (GNS-CNT) hybrids by following a process of iron ion prebombardment on Si wafers, catalyst-free growth of GNSs on CNTs, and high-temperature annealing. Structural observations indicate that the iron ion prebombardment influences the growth of CNTs quite limitedly, and the self-assembled GNSs sparsely distributed on the tips of CNTs with their sharp edges unfolded outside. The field emission study indicates that the maximum emission current density (Jmax) is gradually promoted after these treatments, and the composition with GNSs is helpful for decreasing the operation fields of CNTs. An optimal Jmax up to 85.10 mA/cm(2) is achieved from a 4.65 mm(2) GNS-CNT sample, far larger than 7.41 mA/cm(2) for the as-grown CNTs. This great increase of Jmax is ascribed to the reinforced adhesion of GNS-CNT hybrids to substrates. We propose a rough calculation and find that this adhesion is promoted by 7.37 times after the three-step processing. We consider that both the ion prebombardment produced rough surface and the wrapping of CNT foot by catalyst residuals during thermal processing are responsible for this enhanced adhesion. Furthermore, the three-step prepared GNS-CNT hybrids present excellent field emission stability at high emission current densities (larger than 20 mA/cm(2)) after being perfectly aged.

  8. Microstructures and Mechanical Properties of Weld Metal and Heat-Affected Zone of Electron Beam-Welded Joints of HG785D Steel

    Science.gov (United States)

    Zhang, Qiang; Han, Jianmin; Tan, Caiwang; Yang, Zhiyong; Wang, Junqiang

    2016-12-01

    Vacuum electron beam welding (EBW) process was employed to butt weld 10-mm-thick HG785D high-strength steels. The penetration into the steel was adjusted by beam current. Microstructures at weld metal and heat-affected zone (HAZ) regions were comparatively observed. Mechanical properties of the EBWed joints including Vickers hardness, tensile and Charpy impact tests were evaluated. The results indicated that microstructures at the weld metal consisted of coarse lath martensite and a small amount of acicular martensite, while that in the HAZ was tempered sorbite and martensite. The grain size in the weld metal was found to be larger than that in the HAZ, and its proportion in weld metal was higher. The hardness in the weld metal was higher than the HAZ and base metal. The tensile strength and impact toughness in the HAZ was higher than that in the weld metal. All the behaviors were related to microstructure evolution caused by higher cooling rates and state of base metal. The fracture surfaces of tensile and impact tests on the optimized joint were characterized by uniform and ductile dimples. The results differed significantly from that obtained using arc welding process.

  9. A hybrid electron and photon IMRT planning technique that lowers normal tissue integral patient dose using standard hardware.

    Science.gov (United States)

    Rosca, Florin

    2012-06-01

    To present a mixed electron and photon IMRT planning technique using electron beams with an energy range of 6-22 MeV and standard hardware that minimizes integral dose to patients for targets as deep as 7.5 cm. Ten brain cases, two lung, a thyroid, an abdominal, and a parotid case were planned using two planning techniques: a photon-only IMRT (IMRT) versus a mixed modality treatment (E+IMRT) that includes an enface electron beam and a photon IMRT portion that ensures a uniform target coverage. The electron beam is delivered using a regular cutout placed in an electron cone. The electron energy was chosen to provide a good trade-off between minimizing integral dose and generating a uniform, deliverable plan. The authors choose electron energies that cover the deepest part of PTV with the 65%-70% isodose line. The normal tissue integral dose, the dose for ring structures around the PTV, and the volumes of the 75%, 50%, and 25% isosurfaces were used to compare the dose distributions generated by the two planning techniques. The normal tissue integral dose was lowered by about 20% by the E+IMRT plans compared to the photon-only IMRT ones for most studied cases. With the exception of lungs, the dose reduction associated to the E+IMRT plans was more pronounced further away from the target. The average dose ratio delivered to the 0-2 cm and the 2-4 cm ring structures for brain patients for the two planning techniques were 89.6% and 70.8%, respectively. The enhanced dose sparing away from the target for the brain patients can also be observed in the ratio of the 75%, 50%, and 25% isodose line volumes for the two techniques, which decreases from 85.5% to 72.6% and further to 65.1%, respectively. For lungs, the lateral electron beams used in the E+IMRT plans were perpendicular to the mostly anterior/posterior photon beams, generating much more conformal plans. The authors proved that even using the existing electron delivery hardware, a mixed electron/photon planning

  10. Functional separation of oxidation–reduction reactions and electron transport in PtRu/ND and conductive additive hybrid electrocatalysts during methanol oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yan; Wang, Yanhui [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Bian, Linyan [College of Physics and Chemistry, Henan Polytechnic University, Jiaozuo, Henan 454000 (China); Lu, Rui [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China); Zang, Jianbing, E-mail: jbzang@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2016-02-28

    Graphical abstract: - Highlights: • Functional separation of reactions and electron transport in PtRu/ND + AB (or CNT). • A conductive network was formed after the addition of AB or CNT. • PtRu/ND + AB (or CNT) exhibited enhanced activity and stability than PtRu/ND. - Abstract: Undoped nanodiamond (ND) supported PtRu (PtRu/ND) electrocatalyst for methanol oxidation reactions (MOR) in direct methanol fuel cells was prepared by a microwave-assisted polyol reduction method. Sp{sup 3}-bonded ND possesses high electrochemical stability but low conductivity, while sp{sup 2}-bonded carbon nanomaterials with high conductivity are prone to oxidation. Therefore, the functions of the supporting material were separated in this study. ND (sp{sup 3}), as a support, and AB or CNTs (sp{sup 2}), as a conductive additive, were combined to form the hybrid electrocatalysts PtRu/ND + AB and PtRu/ND + CNT for MOR. The morphology of the electrocatalysts was characterized by scanning electron microscopy and electrochemical measurements were performed using an electrochemical workstation. The results indicated that the electrocatalytic activity of PtRu/ND for MOR was improved with the addition of AB or CNTs as a conductive additive. Moreover, adding CNTs to PtRu/ND as a conductive additive showed better electrocatalytic activities than adding AB, which can be ascribed to the better electron-transfer ability of CNTs.

  11. Interfacial electronic structure and charge transfer of hybrid graphene quantum dot and graphitic carbon nitride nanocomposites: insights into high efficiency for photocatalytic solar water splitting.

    Science.gov (United States)

    Ma, Zuju; Sa, Rongjian; Li, Qiaohong; Wu, Kechen

    2016-01-14

    New metal-free carbon nanodot/carbon nitride (C3N4) nanocomposites have shown to exhibit high efficiency for photocatalytic solar water splitting. (J. Liu, et al., Science, 2015, 347, 970) However, the mechanism underlying the ultrahigh performance of these nanocomposites and consequently the possibilities for further improvements are not at present clear. In this work, we performed hybrid functional calculations and included long-range dispersion corrections to accurately characterize the interfacial electron coupling of the graphene quantum dot-graphitic carbon nitride composites (Gdot/g-C3N4). The results revealed that the band gap of Gdot/g-C3N4 could be engineered by changing the lateral size of Gdots. In particular, the C24H12/g-C3N4 composites present an ideal band gap of 1.92 eV to harvest a large part of solar light. More interestingly, a type-II heterojunction is formed at the interface of the Gdot/g-C3N4 composites, a desirable feature for enhanced photocatalytic activity. The charge redistribution at the interface leads to strong electron depletion above the Gdot sheet and electron accumulation below the g-C3N4 monolayer, potentially facilitating the separation of H2O oxidation and reduction reactions. Furthermore, we suggested that the photocatalytic performance of the Gdot/g-C3N4 nanocomposites can be further improved by decreasing the thickness of Gdots and tuning the size of Gdots.

  12. Hybrid functional study of structural, electronic and magnetic properties of S-doped ZnO with and without neutral vacancy

    Energy Technology Data Exchange (ETDEWEB)

    Debbichi, M., E-mail: mourad_fsm@yahoo.fr [Laboratoire de la matière condensée et nanosciences, Département de Physique, Faculté des Sciences de Monastir, 5019 Monastir (Tunisia); Sakhraoui, T. [Laboratoire de la matière condensée et nanosciences, Département de Physique, Faculté des Sciences de Monastir, 5019 Monastir (Tunisia); Debbichi, L. [Institut Carnot de Bourgogne, UMR 6303, Université de Bourgogne-CNRS, 21078 Dijon (France); Said, M. [Laboratoire de la matière condensée et nanosciences, Département de Physique, Faculté des Sciences de Monastir, 5019 Monastir (Tunisia)

    2013-11-25

    Highlights: •S-doped ZnO have been investigated by DFT and EPM. •Good agreement with the experimental data is obtained by HSE (α = 0.28) functional on lattice parameters and band gap energy. •Zn vacancy introduced in S doped ZnO is studied by HSE to determine its electronic and magnetic properties. -- Abstract: The structural and electronic properties of S-doped ZnO are investigated by density functional theory (DFT) and empirical pseudopotential method (EPM). Using the Heyd–Scuseria–Ernzerhof (HSE) hybrid functional with an adjusted mixing coefficient α, we obtain a good agreement on lattice parameters and band gap energy with the available experimental data. We have also investigate the Zn-vacancy effects on the electronic and magnetic properties of S-doped ZnO. Our calculations demonstrate that S impurity prefers to be close to the cation vacancy in the apical position. The magnetic analysis with the HSE functional shows a triplet state character with a total magnetic moment of 1.81 μ{sub B}, which is mainly arises from the p-orbitals of the atoms around the Zn-vacancy (15% from S, 12% from Zn and 73% from O-atoms). The substitution of S by an isovalent atom decreases the total magnetic moments of the system and weakens the local triplet state without destroying it.

  13. Structural, electronic and energetic properties of giant icosahedral fullerenes up to C6000: insights from an ab initio hybrid DFT study.

    Science.gov (United States)

    Noël, Yves; De La Pierre, Marco; Zicovich-Wilson, Claudio M; Orlando, Roberto; Dovesi, Roberto

    2014-07-14

    The properties of the (n,n) icosahedral family of carbon fullerenes up to n = 10 (6000 atoms) have been investigated through ab initio quantum-mechanical simulation by using a Gaussian type basis set of double zeta quality with polarization functions (84,000 atomic orbitals for the largest case), the hybrid B3LYP functional and the CRYSTAL14 code featuring generalization of symmetry treatment. The geometry of giant fullerenes shows hybrid features, between a polyhedron and a sphere; as n increases, it approaches the former. Hexagon rings at face centres take a planar, graphene-like configuration; the 12 pentagon rings at vertices impose, however, a severe structural constraint to which hexagon rings at the edges must adapt smoothly, adopting a bent (rather than sharp) transversal profile and an inward longitudinal curvature. The HOMO and LUMO electronic levels, as well as the band gap, are well described using power laws. The gap is predicted to become zero for n ≥ 34 (69,360 atoms). The atomic excess energy with respect to the ideal graphene sheet goes to zero following the log(Nat)/Nat law, which is well described through the continuum elastic theory applied to graphene; the limits for the adopted model are briefly outlined. Compared to larger fullerenes of the series, C60 shows unique features with respect to all the considered properties; C240 presents minor structural and energetic peculiarities, too.

  14. The electronic structure of organic-inorganic hybrid compounds: (NH₄)₂CuCl₄, (CH₃NH₃)₂CuCl₄ and (C₂H₅NH₃)₂CuCl₄.

    Science.gov (United States)

    Zolfaghari, P; de Wijs, G A; de Groot, R A

    2013-07-24

    Hybrid organic-inorganic compounds are an intriguing class of materials that have been experimentally studied over the past few years because of a potential broad range of applications. The electronic and magnetic properties of three organic-inorganic hybrid compounds with compositions (NH4)2CuCl4, (CH3NH3)2CuCl4 and (C2H5NH3)2CuCl4 are investigated for the first time with density functional theory plus on-site Coulomb interaction. A strong Coulomb interaction on the copper causes a relatively weak exchange coupling within the layers of the octahedral network, in good agreement with experiment. The character of the exchange interaction (responsible for magnetic behavior) is analyzed. The calculations reveal that (C2H5NH3)2CuCl4 has the strongest Jahn-Teller (JT) distortion in comparison with the two other compounds. The easy axis of magnetization is investigated, showing a weak anisotropic interaction between inter-layer Cu(2+) ions in the (C2H5NH3)2CuCl4 structure. Orbital ordering is concluded from our partial density of states calculations: a cooperation of the JT distortion with an antiferro-distortive pattern.

  15. First principle study of electronic and optical properties of molecular ion (BF4- ) substituted hybrid perovskite (CH3NH3PbI3)

    Science.gov (United States)

    Rani, Shalu; Singh, Poorva

    2017-05-01

    Hybrid organic/inorganic perovskites have garnered significant research interest due to the extraordinary increase in energy conversion efficiency as witnessed in photovoltaic devices based on CH3NH3PbI3. An experimental report has shown that the substitution of BF4- in the perovskite CH3NH3PbI3 can lead to the high efficiency for solar cell. Employing first-principles calculations based on density functional theory, we have studied several different perovskites CH3NH3PbI3 , CH3NH3PbI2BF4, CH3NH3PbI(BF4)2, CH3NH3Pb(BF4)3 and examined their electronic structure and optical properties.

  16. ZnO Nanorods on a LaAlO 3 -SrTiO 3 Interface: Hybrid 1D-2D Diodes with Engineered Electronic Properties

    KAUST Repository

    Bera, Ashok

    2015-12-28

    Integrating nanomaterials with different dimensionalities and properties is a versatile approach toward realizing new functionalities in advanced devices. Here, a novel diode-type heterostructure is reported consisting of 1D semiconducting ZnO nanorods and 2D metallic LaAlO3-SrTiO3 interface. Tunable insulator-to-metal transitions, absent in the individual components, are observed as a result of the competing temperature-dependent conduction mechanisms. Detailed transport analysis reveals direct tunneling at low bias, Fowler-Nordheim tunneling at high forward bias, and Zener breakdown at high reverse bias. Our results highlight the rich electronic properties of such artificial diodes with hybrid dimensionalities, and the design principle may be generalized to other nanomaterials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. ZnO Nanorods on a LaAlO3 -SrTiO3 Interface: Hybrid 1D-2D Diodes with Engineered Electronic Properties.

    Science.gov (United States)

    Bera, Ashok; Lin, Weinan; Yao, Yingbang; Ding, Junfeng; Lourembam, James; Wu, Tom

    2016-02-10

    Integrating nanomaterials with different dimensionalities and properties is a versatile approach toward realizing new functionalities in advanced devices. Here, a novel diode-type heterostructure is reported consisting of 1D semiconducting ZnO nanorods and 2D metallic LaAlO3-SrTiO3 interface. Tunable insulator-to-metal transitions, absent in the individual components, are observed as a result of the competing temperature-dependent conduction mechanisms. Detailed transport analysis reveals direct tunneling at low bias, Fowler-Nordheim tunneling at high forward bias, and Zener breakdown at high reverse bias. Our results highlight the rich electronic properties of such artificial diodes with hybrid dimensionalities, and the design principle may be generalized to other nanomaterials.

  18. Application of P-wave Hybrid Theory to the Scattering of Electrons from He+ and Resonances in He and H ion

    Science.gov (United States)

    Bhatia, A. K.

    2012-01-01

    The P-wave hybrid theory of electron-hydrogen elastic scattering [Phys. Rev. A 85, 052708 (2012)] is applied to the P-wave scattering from He ion. In this method, both short-range and long-range correlations are included in the Schroedinger equation at the same time, by using a combination of a modified method of polarized orbitals and the optical potential formalism. The short-correlation functions are of Hylleraas type. It is found that the phase shifts are not significantly affected by the modification of the target function by a method similar to the method of polarized orbitals and they are close to the phase shifts calculated earlier by Bhatia [Phys. Rev. A 69, 032714 (2004)]. This indicates that the correlation function is general enough to include the target distortion (polarization) in the presence of the incident electron. The important fact is that in the present calculation, to obtain similar results only a 20-term correlation function is needed in the wave function compared to the 220- term wave function required in the above-mentioned calculation. Results for the phase shifts, obtained in the present hybrid formalism, are rigorous lower bounds to the exact phase shifts. The lowest P-wave resonances in He atom and hydrogen ion have been calculated and compared with the results obtained using the Feshbach projection operator formalism [Phys. Rev. A, 11, 2018 (1975)]. It is concluded that accurate resonance parameters can be obtained by the present method, which has the advantage of including corrections due to neighboring resonances, bound states and the continuum in which these resonance are embedded.

  19. Multifunctional Inverse Opal-Like TiO2 Electron Transport Layer for Efficient Hybrid Perovskite Solar Cells.

    Science.gov (United States)

    Chen, Xiao; Yang, Shuang; Zheng, Yi Chu; Chen, Ying; Hou, Yu; Yang, Xiao Hua; Yang, Hua Gui

    2015-09-01

    A novel multifunctional inverse opal-like TiO2 electron transport layer (IOT-ETL) is designed to replace the traditional compact layer and mesoporous scaffold layer in perovskite solar cells (PSCs). Improved light harvesting efficiency and charge transporting performance in IOT-ETL based PSCs yield high power conversion efficiency of 13.11%.

  20. Effect of Bulk Water Concentration on Mantle Wedge Hybridization by Rhyolitic Sediment Melt - Implications for Generation of K-rich Basalts to Andesites in Subduction Zones

    Science.gov (United States)

    Mallik, A.; Dasgupta, R.; Nelson, J. M.; Tsuno, K.

    2014-12-01

    basaltic to andesitic compositions can be produced by partial melting of sediment melt-fluxed wedge peridotite hybrids with variable water contents.

  1. Multicentre clinical trials' data management: a hybrid solution to exploit the strengths of electronic data capture and electronic health records systems.

    Science.gov (United States)

    Fraccaro, Paolo; Dentone, Chiara; Fenoglio, Daniela; Giacomini, Mauro

    2013-12-01

    Clinical Trials (CTs) are indispensable instruments for evidence-based medicine and frequently necessitate the management, sharing and analysis of large amounts of data amongst partners in different locations. To effectively satisfy these requirements, the proposed solution combines a web platform and a Clinical Data Management System (CDMS) to exploit the strengths of Electronic Health Records (EHR) and Electronic Data Capture (EDC) systems. The core of the proposal is a relational database which has high data structuring characteristics and utilises biomedical controlled vocabularies (e.g. LOINC and ICD). In addition, units and normality ranges were collected for data comparison through the application of the Z-score transformation. The obtained CDMS preserves the EDC's flexibility and user autonomy and permits the creation of patient cohorts, as in the EHR. Accordingly, clinical information, after the initial recording, is available for different simultaneous multicentre CTs. Furthermore, interface runtime controls guarantee high data quality during data entering processes. Currently, the proposed system has been developed in the HIV and eye diseases fields in Italy. The proposed solution is flexible and suitable to perform multicentre research within a varying range of medical domains. In the future, the automatic importation of information from hospitals has been planned through an HL7 standard interface which would improve both data quantity and quality.

  2. Timing of Deformation in the Central Metasedimentary Belt Boundary Thrust Zone (CMBbtz), southern Ontario, Canada, from Electron Microprobe Dating of Monazite

    Science.gov (United States)

    Markley, M. J.; Dunn, S. R.; Peck, W. H.; Jercinovic, M. J.; Williams, M. L.

    2015-12-01

    In the Grenville Province of Southern Ontario, the Central Metasedimentary Belt boundary thrust zone (CMBbtz) is a crustal-scale tectonic boundary between the older, granulite-facies Central Gneiss Belt to the NW and the younger, amphibolite-facies Central Metasedimentary Belt to the SE. Although there are a range of tectonic models for the CMBbtz, most workers agree it is a major tectonic boundary that accommodated ductile thrusting and crustal shortening during the Ottawan phase of the Grenville Orogeny (~1080-1020 Ma). Some studies suggest that ductile thrusting in the CMBbtz was roughly synchronous with synorogenic extensional collapse below an orogenic lid. Previous geochronological studies also provide evidence of earlier deformation and/or metamorphic events in the CMBbtz, although the relation between deformation in the CMBbtz to the Elzeviran (~1230 Ma) and Shawinigan (~1180 Ma) orogenies is unclear. Our study is the first to report in situ electron microprobe monazite (mnz) dates from amphibolite-grade ortho- and para-gneisses of the CMBbtz. Our results are broadly consistent with other chronometers. We present dates from 132 age-domains within 83 mnz grains in 14 samples. Although our data provide strong evidence for deformation and metamorphism along the length of the CMBbtz during the Ottawan (1080-1020 Ma), we also report two other clusters of ages: 1140-1110 Ma and 1230-1170 Ma. The latter cluster falls between the widely accepted ranges for the Elzeviran and Shawinigan orogenies. In addition, some individual outcrops, particularly those in Killaloe and Minden, show mnz ages spanning over 200 m.y., and the setting and compositions of individual monazite domains allow us to link mnz growth to episodes of garnet growth during multiple events. Together these data indicate an unexpectedly continuous and long-lived period of deformation and metamorphism in the CMBbtz.

  3. ZrO2/TiO2 Electron Collection Layer for Efficient Meso-Superstructured Hybrid Perovskite Solar Cells.

    Science.gov (United States)

    Mejía Escobar, Mario Alejandro; Pathak, Sandeep; Liu, Jiewei; Snaith, Henry J; Jaramillo, Franklin

    2017-01-25

    Since the first reports of efficient organic-inorganic perovskite solar cells in 2012, an explosion of research activity has emerged around the world, which has led to a rise in the power conversion efficiencies (PCEs) to over 20%. Despite the impressive efficiency, a key area of the device which remains suboptimal is the electron extraction layer and its interface with the photoactive perovskite. Here, we implement an electron collection "bilayer" composed of a thin layer of zirconia coated with titania, sitting upon the transparent conductive oxide fluorine-doped tin oxide (FTO). With this double collection layer we have reached up to 17.9% power conversion efficiency, delivering a stabilized power output (SPO) of 17.0%, measured under simulated AM 1.5 sunlight of 100 mW cm(-2) irradiance. Finally, we propose a mechanism of the charge transfer processes within the fabricated architectures in order to explain the obtained performance of the devices.

  4. Theoretical and experimental investigations of optical, structural and electronic properties of the lower-dimensional hybrid [NH3-(CH2)10-NH3]ZnCl4

    Science.gov (United States)

    El Mrabet, R.; Kassou, S.; Tahiri, O.; Belaaraj, A.; Guionneau, P.

    2016-10-01

    In the current study, a combination between theoretical and experimental studies has been made for the hybrid perovskite [NH3-(CH2)10-NH3]ZnCl4. The density functional theory (DFT) was performed to investigate structural and electronic properties of the tilted compound. A local approximation (LDA) and semi-local approach (GGA) were employed. The results are obtained using, respectively, the local exchange correlation functional of Perdew-Wang 92 (PW92) and semi local functional of Perdew-Burke-Ernzerhof (PBE). The optimized cell parameters are in good agreement with the experimental results. Electronic properties have been studied through the calculation of band structures and density of state (DOS), while structural properties are investigated by geometry optimization of the cell. Fritz-Haber-Institute (FHI) pseudopotentials were employed to perform all calculations. The optical diffuse reflectance spectra was mesured and applied to deduce the refractive index ( n), the extinction coefficient ( k), the absorption coefficient (α), the real and imaginary dielectric permittivity parts (ɛr,ɛi)) and the optical band gap energy Eg. The optical band gap energy value shows good consistent with that obtained from DFT calculations and reveals the insulating behavior of the material.

  5. A hybrid functional study of the electronic and optical properties of tetragonal PbO-type phase of ZnO under pressure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qingbo [State Key Laboratory of Material Processing and Die and Mould Technology and School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China); School of Mathematics and Physics, China University of Geosciences (Wuhan), Wuhan 430074, Hubei (China); Wen, Yanwei [State Key Laboratory of Material Processing and Die and Mould Technology and School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China); Chen, Rong, E-mail: rongchen@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology and School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China); Shan, Bin, E-mail: bshan@mail.hust.edu.cn [State Key Laboratory of Material Processing and Die and Mould Technology and School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China); Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, TX 75080 (United States)

    2014-02-15

    Highlights: • HSE was used to study the electronic and optical properties of new B10 ZnO phase. • Band gap is ranging from 6.08 to 7.06 eV under high pressure from 236 to 316 GPa. • The optical constants undergo a blue shift with the increasing pressure. -- Abstract: To extend our knowledge on the tetragonal PbO-type (B10) phase of ZnO under high pressure, we used the hybrid functional theory to calculate its electronic and optical properties. Our calculations indicate that the B10 phase is a transparent insulator and has an indirect band gap ranging from 6.08 to 7.06 eV with pressure increasing from 236 to 316 GPa. The B10 phase under 236 GPa has excellent dielectric properties except metallic behaviors at around 25 and 37 eV photon excitation. We found a blue shift in optical properties of the B10 phase with the increase of pressure.

  6. Ground-state phase diagram, fermionic entanglement and kinetically-induced frustration in a hybrid ladder with localized spins and mobile electrons

    Science.gov (United States)

    Carvalho, R. C. P.; Pereira, M. S. S.; de Oliveira, I. N.; Strečka, J.; Lyra, M. L.

    2017-09-01

    We introduce an exactly solvable hybrid spin-ladder model containing localized nodal Ising spins and interstitial mobile electrons, which are allowed to perform a quantum-mechanical hopping between the ladder’s legs. The quantum-mechanical hopping process induces an antiferromagnetic coupling between the ladder’s legs that competes with a direct exchange coupling of the nodal spins. The model is exactly mapped onto the Ising spin ladder with temperature-dependent two- and four-spin interactions, which is subsequently solved using the transfer-matrix technique. We report the ground-state phase diagram and compute the fermionic concurrence to characterize the quantum entanglement between the pair of interstitial mobile electrons. We further provide a detailed analysis of the local spin ordering including the pair and four-spin correlation functions around an elementary plaquette, as well as, the local ordering diagrams. It is shown that a complex sequence of distinct local orderings and frustrated correlations takes place when the model parameters drive the investigated system close to a zero-temperature triple coexistence point.

  7. A hybrid digital-signature and zero-watermarking approach for authentication and protection of sensitive electronic documents.

    Science.gov (United States)

    Tayan, Omar; Kabir, Muhammad N; Alginahi, Yasser M

    2014-01-01

    This paper addresses the problems and threats associated with verification of integrity, proof of authenticity, tamper detection, and copyright protection for digital-text content. Such issues were largely addressed in the literature for images, audio, and video, with only a few papers addressing the challenge of sensitive plain-text media under known constraints. Specifically, with text as the predominant online communication medium, it becomes crucial that techniques are deployed to protect such information. A number of digital-signature, hashing, and watermarking schemes have been proposed that essentially bind source data or embed invisible data in a cover media to achieve its goal. While many such complex schemes with resource redundancies are sufficient in offline and less-sensitive texts, this paper proposes a hybrid approach based on zero-watermarking and digital-signature-like manipulations for sensitive text documents in order to achieve content originality and integrity verification without physically modifying the cover text in anyway. The proposed algorithm was implemented and shown to be robust against undetected content modifications and is capable of confirming proof of originality whilst detecting and locating deliberate/nondeliberate tampering. Additionally, enhancements in resource utilisation and reduced redundancies were achieved in comparison to traditional encryption-based approaches. Finally, analysis and remarks are made about the current state of the art, and future research issues are discussed under the given constraints.

  8. A Hybrid Digital-Signature and Zero-Watermarking Approach for Authentication and Protection of Sensitive Electronic Documents

    Directory of Open Access Journals (Sweden)

    Omar Tayan

    2014-01-01

    Full Text Available This paper addresses the problems and threats associated with verification of integrity, proof of authenticity, tamper detection, and copyright protection for digital-text content. Such issues were largely addressed in the literature for images, audio, and video, with only a few papers addressing the challenge of sensitive plain-text media under known constraints. Specifically, with text as the predominant online communication medium, it becomes crucial that techniques are deployed to protect such information. A number of digital-signature, hashing, and watermarking schemes have been proposed that essentially bind source data or embed invisible data in a cover media to achieve its goal. While many such complex schemes with resource redundancies are sufficient in offline and less-sensitive texts, this paper proposes a hybrid approach based on zero-watermarking and digital-signature-like manipulations for sensitive text documents in order to achieve content originality and integrity verification without physically modifying the cover text in anyway. The proposed algorithm was implemented and shown to be robust against undetected content modifications and is capable of confirming proof of originality whilst detecting and locating deliberate/nondeliberate tampering. Additionally, enhancements in resource utilisation and reduced redundancies were achieved in comparison to traditional encryption-based approaches. Finally, analysis and remarks are made about the current state of the art, and future research issues are discussed under the given constraints.

  9. A hybrid method for protection against threats to a network infrastructure for an electronic warfare management system

    Science.gov (United States)

    Byłak, Michał; RóŻański, Grzegorz

    2017-04-01

    The article presents the concept of ensuring the security of network information infrastructure for the management of Electronic Warfare (EW) systems. The concept takes into account the reactive and proactive tools against threats. An overview of the methods used to support the safety of IT networks and information sources about threats is presented. Integration of mechanisms that allow for effective intrusion detection and rapid response to threats in a network has been proposed. The architecture of the research environment is also presented.

  10. OPTESIM, a versatile toolbox for numerical simulation of electron spin echo envelope modulation (ESEEM) that features hybrid optimization and statistical assessment of parameters.

    Science.gov (United States)

    Sun, Li; Hernandez-Guzman, Jessica; Warncke, Kurt

    2009-09-01

    Electron spin echo envelope modulation (ESEEM) is a technique of pulsed-electron paramagnetic resonance (EPR) spectroscopy. The analyis of ESEEM data to extract information about the nuclear and electronic structure of a disordered (powder) paramagnetic system requires accurate and efficient numerical simulations. A single coupled nucleus of known nuclear g value (g(N)) and spin I=1 can have up to eight adjustable parameters in the nuclear part of the spin Hamiltonian. We have developed OPTESIM, an ESEEM simulation toolbox, for automated numerical simulation of powder two- and three-pulse one-dimensional ESEEM for arbitrary number (N) and type (I, g(N)) of coupled nuclei, and arbitrary mutual orientations of the hyperfine tensor principal axis systems for N>1. OPTESIM is based in the Matlab environment, and includes the following features: (1) a fast algorithm for translation of the spin Hamiltonian into simulated ESEEM, (2) different optimization methods that can be hybridized to achieve an efficient coarse-to-fine grained search of the parameter space and convergence to a global minimum, (3) statistical analysis of the simulation parameters, which allows the identification of simultaneous confidence regions at specific confidence levels. OPTESIM also includes a geometry-preserving spherical averaging algorithm as default for N>1, and global optimization over multiple experimental conditions, such as the dephasing time (tau) for three-pulse ESEEM, and external magnetic field values. Application examples for simulation of (14)N coupling (N=1, N=2) in biological and chemical model paramagnets are included. Automated, optimized simulations by using OPTESIM lead to a convergence on dramatically shorter time scales, relative to manual simulations.

  11. Amorphous Tin Oxide as a Low-Temperature-Processed Electron-Transport Layer for Organic and Hybrid Perovskite Solar Cells

    KAUST Repository

    Barbe, Jeremy

    2017-02-08

    Chemical bath deposition (CBD) of tin oxide (SnO) thin films as an electron-transport layer (ETL) in a planar-heterojunction n-i-p organohalide lead perovskite and organic bulk-heterojunction (BHJ) solar cells is reported. The amorphous SnO (a-SnO) films are grown from a nontoxic aqueous bath of tin chloride at a very low temperature (55 °C) and do not require postannealing treatment to work very effectively as an ETL in a planar-heterojunction n-i-p organohalide lead perovskite or organic BHJ solar cells, in lieu of the commonly used ETL materials titanium oxide (TiO) and zinc oxide (ZnO), respectively. Ultraviolet photoelectron spectroscopy measurements on the glass/indium-tin oxide (ITO)/SnO/methylammonium lead iodide (MAPbI)/2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenylamine)-9,9′-spirobifluorene device stack indicate that extraction of photogenerated electrons is facilitated by a perfect alignment of the conduction bands at the SnO/MAPbI interface, while the deep valence band of SnO ensures strong hole-blocking properties. Despite exhibiting very low electron mobility, the excellent interfacial energetics combined with high transparency (E > 4 eV) and uniform substrate coverage make the a-SnO ETL prepared by CBD an excellent candidate for the potentially low-cost and large-scale fabrication of organohalide lead perovskite and organic photovoltaics.

  12. The locations and amounts of endogenous ions and elements in the cap and elongating zone of horizontally oriented roots of Zea mays L.: an electron-probe EDS study

    Science.gov (United States)

    Moore, R.; Cameron, I. L.; Hunter, K. E.; Olmos, D.; Smith, N. K.

    1987-01-01

    We used quantitative electron-probe energy-dispersive x-ray microanalysis to localize endogenous Na, Cl, K, P, S, Mg and Ca in cryofixed and freeze-dried cryosections of the cap (i.e. the putative site of graviperception) and elongating zone (i.e. site of gravicurvature) of horizontally oriented roots of Zea mays. Ca, Na, Cl, K and Mg accumulate along the lower side of caps of horizontally oriented roots. The most dramatic asymmetries of these ions occur in the apoplast, especially the mucilage. We could not detect any significant differences in the concentrations of these ions in the central cytoplasm of columella cells along the upper and lower sides of caps of horizontally-oriented roots. However, the increased amounts of Na, Cl, K and Mg in the longitudinal walls of columella cells along the lower side of the cap suggest that these ions may move down through the columella tissue of horizontally-oriented roots. Ca also accumulates (largely in the mucilage) along the lower side of the elongating zone of horizontally-oriented roots, while Na, P, Cl and K tend to accumulate along the upper side of the elongating zone. Of these ions, only K increases in concentration in the cytoplasm and longitudinal walls of cortical cells in the upper vs lower sides of the elongating zone. These results indicate that (1) gravity-induced asymmetries of ions differ significantly in the cap and elongating zone of graviresponding roots, (2) Ca accumulates along the lower side of the cap and elongating zone of graviresponding roots, (3) increased growth of the upper side of the elongating zone of horizontally-oriented roots correlates positively with increased amounts of K in the cytoplasm and longitudinal walls of cortical cells, and (4) the apoplast (especially the mucilage) may be an important component of the pathway via which ions move in graviresponding rots of Zea mays. These results are discussed relative to mechanisms for graviperception and gravicurvature of roots.

  13. Liquid Water- and Heat-Resistant Hybrid Perovskite Photovoltaics via an Inverted ALD Oxide Electron Extraction Layer Design.

    Science.gov (United States)

    Kim, In Soo; Cao, Duyen H; Buchholz, D Bruce; Emery, Jonathan D; Farha, Omar K; Hupp, Joseph T; Kanatzidis, Mercouri G; Martinson, Alex B F

    2016-12-14

    Despite rapid advances in conversion efficiency (>22%), the environmental stability of perovskite solar cells remains a substantial barrier to commercialization. Here, we show a significant improvement in the stability of inverted perovskite solar cells against liquid water and high operating temperature (100 °C) by integrating an ultrathin amorphous oxide electron extraction layer via atomic layer deposition (ALD). These unencapsulated inverted devices exhibit a stable operation over at least 10 h when subjected to high thermal stress (100 °C) in ambient environments, as well as upon direct contact with a droplet of water without further encapsulation.

  14. Perovskite oxide SrTiO3 as an efficient electron transporter for hybrid perovskite solar cells

    KAUST Repository

    Bera, Ashok

    2014-12-11

    In this work, we explored perovskite oxide SrTiO3 (STO) for the first time as the electron-transporting layer in organolead trihalide perovskite solar cells. The steady-state photoluminescence (PL) quenching and transient absorption experiments revealed efficient photoelectron transfer from CH3NH3PbI3-xClx to STO. Perovskite solar cells with meso-STO exhibit an open circuit voltage of 1.01 V, which is 25% higher than the value of 0.81 V achieved in the control device with the conventional meso-TiO2. In addition, an increase of 17% in the fill factor was achieved by tailoring the thickness of the meso-STO layer. We found that the application of STO leads to uniform perovskite layers with large grains and complete surface coverage, leading to a high shunt resistance and improved performance. These findings suggest STO as a competitive candidate as electron transport material in organometal perovskite solar cells.

  15. Photoinduced electron transfer pathways in hydrogen-evolving reduced graphene oxide-boosted hybrid nano-bio catalyst.

    Science.gov (United States)

    Wang, Peng; Dimitrijevic, Nada M; Chang, Angela Y; Schaller, Richard D; Liu, Yuzi; Rajh, Tijana; Rozhkova, Elena A

    2014-08-26

    Photocatalytic production of clean hydrogen fuels using water and sunlight has attracted remarkable attention due to the increasing global energy demand. Natural and synthetic dyes can be utilized to sensitize semiconductors for solar energy transformation using visible light. In this study, reduced graphene oxide (rGO) and a membrane protein bacteriorhodopsin (bR) were employed as building modules to harness visible light by a Pt/TiO2 nanocatalyst. Introduction of the rGO boosts the nano-bio catalyst performance that results in hydrogen production rates of approximately 11.24 mmol of H2 (μmol protein)(-1) h(-1). Photoelectrochemical measurements show a 9-fold increase in photocurrent density when TiO2 electrodes were modified with rGO and bR. Electron paramagnetic resonance and transient absorption spectroscopy demonstrate an interfacial charge transfer from the photoexcited rGO to the semiconductor under visible light.

  16. Energetic stability, oxidation states, and electronic structure of Bi-doped NaTaO3: a first-principles hybrid functional study.

    Science.gov (United States)

    Joo, Paul H; Behtash, Maziar; Yang, Kesong

    2016-01-14

    We studied the defect formation energies, oxidation states of the dopants, and electronic structures of Bi-doped NaTaO3 using first-principles hybrid density functional theory calculations. Three possible structural models, including Bi-doped NaTaO3 with Bi at the Na site (Bi@Na), with Bi at the Ta site (Bi@Ta), and with Bi at both Na and Ta sites [Bi@(Na,Ta)], are constructed. Our results show that the preferred doping sites of Bi are strongly related to the preparation conditions of NaTaO3. It is energetically more favorable to form a Bi@Na structure under Na-poor conditions, to form a Bi@Ta structure under Na-rich conditions, and to form a Bi@(Na,Ta) structure under mildly Na-rich conditions. The Bi@Na doped model shows an n-type conducting character along with an expected blueshift of the optical absorption edge, in which the Bi atoms exist as Bi(3+) (6s(2)6p(0)). The Bi@Ta doped model has empty gap states consisting of Bi 6s states in its band gap, which can lead to visible-light absorption via the electron transition among the valence band, the conduction band, and the gap states. The Bi dopant is present as a Bi(5+) ion in this model, consistent with the experimental results. In contrast, the Bi@(Na,Ta) doped model has occupied gap states consisting of Bi 6s states in its band gap, and thus visible-light absorption is also expected in this system due to electron excitation from these occupied states to the conduction band, in which the Bi dopants exist as Bi(3+) ions. Our first-principles electronic structure calculations revealed the relationship between the Bi doping sites and the material preparation conditions, and clarified the oxidation states of Bi dopants in NaTaO3 as well as the origin of different visible-light photocatalytic hydrogen evolution behaviors in Bi@Ta and Bi@(Na,Ta) doped NaTaO3. This work can provide a useful reference for preparing a Bi-doped NaTaO3 photocatalyst with desired doping sites.

  17. Real-space and plane-wave hybrid method for electronic structure calculations for two-dimensional materials

    Science.gov (United States)

    Do, V. Nam; Le, H. Anh; Vu, V. Thieu

    2017-04-01

    We propose a computational approach to combining the plane-wave method and the real-space treatment to describe the periodic variation in the material plane and the decay of wave functions from the material surfaces. The proposed approach is natural for two-dimensional material systems and thus may circumvent some intrinsic limitations involving the artificial replication of material layers in traditional supercell methods. In particular, we show that the proposed method is easy to implement and, especially, computationally effective since low-cost computational algorithms, such as iterative and recursive techniques, can be used to treat matrices with block tridiagonal structure. Using this approach we show first-principles features that supplement the current knowledge of some fundamental issues in bilayer graphene systems, including the coupling between the two graphene layers, the preservation of the σ band of monolayer graphene in the electronic structure of the bilayer system, and the differences in low-energy band structure between the AA- and AB-stacked configurations.

  18. A zero dimensional hybrid organic-inorganic perovskite ZnCl4 based: Synthesis, crystal structure, UV-vis, and electronic properties

    Science.gov (United States)

    El Mrabet, Rajae; Kassou, Said; Tahiri, Obaida; Belaaraj, Abdesselam; El Ammari, Lahcen; Saadi, Mohamed

    2017-08-01

    A low dimensional hybrid perovskite-like system [H3Nsbnd (CH2)8sbnd NH3]ZnCl4 was synthesized by slow evaporation method at room temperature. Single crystal X-ray diffraction was used to characterize the crystal structure. The compound crystallizes into triclinic system P-1 space group with mutually surrounded inorganic (ZnCl4)-2 organic (H3Nsbnd (CH2)8sbnd NH3) entities, and the following unit cell parameters: a = 6.9998(1) Å, b = 10.7846(2) Å, c = 11.0332(2) Å, α = 83.1730(10)°, β = 82.0490(10)°, γ = 73.2820(10)°, V = 787.27(2) Å3 and Z = 2. The optical band gap deduced from UV-visible spectroscopy was found to be 4.9 eV. Hirshfeld surface analysis shows the importance of hydrogen bonding interactions to ensure the cohesion of the studied crystal. The band structures and electronic properties, such as total and partial densities of state, were investigated by density functional theory (DFT) using a local LDA and semi local GGA approaches. The obtained results reveal the insulating behavior of the material.

  19. Efficient Hybrid White Organic Light-Emitting Diodes for Application of Triplet Harvesting with Simple Structure

    CERN Document Server

    Hwang, Kyo Min; Lee, Sungkyu; Yoo, Han Kyu; Baek, Hyun Jung; Kim, Jwajin; Yoon, Seung Soo; Kim, Young Kwan

    2016-01-01

    In this study, we fabricated hybrid white organic light-emitting diodes (WOLEDs) based on triplet harvesting with simple structure. All the hole transporting material and host in emitting layer (EML) of devices were utilized with same material by using N,N'-di-1-naphthalenyl-N,N'-diphenyl-[1,1':4',1":4",1"'-quaterphenyl]-4,4"'-diamine (4P-NPD) which were known to be blue fluorescent material. Simple hybrid WOLEDs were fabricated three color with blue fluorescent and green, red phosphorescent materials. We was investigated the effect of triplet harvesting (TH) by exciton generation zone on simple hybrid WOLEDs. Characteristic of simple hybrid WOLEDs were dominant hole mobility, therefore exciton generation zone was expected in EML. Additionally, we was optimization thickness of hole transporting layer and electron transporting layer was fabricated a simple hybrid WOLEDs. Simple hybrid WOLED exhibits maximum luminous efficiency of 29.3 cd/A and maximum external quantum efficiency of 11.2%. Commission Internatio...

  20. Hybrid photon detectors

    CERN Document Server

    D'Ambrosio, C

    2003-01-01

    Hybrid photon detectors detect light via vacuum photocathodes and accelerate the emitted photoelectrons by an electric field towards inversely polarized silicon anodes, where they are absorbed, thus producing electron-hole pairs. These, in turn, are collected and generate electronic signals on their ohmic contacts. This review first describes the characteristic properties of the main components of hybrid photon detectors: light entrance windows, photocathodes, and silicon anodes. Then, essential relations describing the trajectories of photoelectrons in electric and magnetic fields and their backscattering from the silicon anodes are derived. Depending on their anode configurations, three families of hybrid photon detectors are presented: hybrid photomultiplier tubes with single anodes for photon counting with high sensitivity and for gamma spectroscopy; multi-anode photon detector tubes with anodes subdivided into square or hexagonal pads for position-sensitive photon detection; imaging silicon pixel array t...

  1. A hybrid electron cyclotron resonance metal ion source with integrated sputter magnetron for the production of an intense Al{sup +} ion beam

    Energy Technology Data Exchange (ETDEWEB)

    Weichsel, T., E-mail: tim.weichsel@fep.fraunhofer.de; Hartung, U.; Kopte, T. [Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, 01277 Dresden (Germany); Zschornack, G. [Institute of Solid State Physics, Dresden University of Technology, 01062 Dresden, Germany and Helmholtz-Zentrum Dresden-Rossendorf e.V., Institute of Ion Beam Physics and Materials Research, Dresden (Germany); Kreller, M.; Philipp, A. [DREEBIT GmbH, 01900 Grossroehrsdorf (Germany)

    2015-09-15

    A metal ion source prototype has been developed: a combination of magnetron sputter technology with 2.45 GHz electron cyclotron resonance (ECR) ion source technology—a so called magnetron ECR ion source (MECRIS). An integrated ring-shaped sputter magnetron with an Al target is acting as a powerful metal atom supply in order to produce an intense current of singly charged metal ions. Preliminary experiments show that an Al{sup +} ion current with a density of 167 μA/cm{sup 2} is extracted from the source at an acceleration voltage of 27 kV. Spatially resolved double Langmuir probe measurements and optical emission spectroscopy were used to study the plasma states of the ion source: sputter magnetron, ECR, and MECRIS plasma. Electron density and temperature as well as Al atom density were determined as a function of microwave and sputter magnetron power. The effect of ECR heating is strongly pronounced in the center of the source. There the electron density is increased by one order of magnitude from 6 × 10{sup 9} cm{sup −3} to 6 × 10{sup 10} cm{sup −3} and the electron temperature is enhanced from about 5 eV to 12 eV, when the ECR plasma is ignited to the magnetron plasma. Operating the magnetron at constant power, it was observed that its discharge current is raised from 1.8 A to 4.8 A, when the ECR discharge was superimposed with a microwave power of 2 kW. At the same time, the discharge voltage decreased from about 560 V to 210 V, clearly indicating a higher plasma density of the MECRIS mode. The optical emission spectrum of the MECRIS plasma is dominated by lines of excited Al atoms and shows a significant contribution of lines arising from singly ionized Al. Plasma emission photography with a CCD camera was used to prove probe measurements and to identify separated plasma emission zones originating from the ECR and magnetron discharge.

  2. Microstructure and mechanical properties of hybrid fabricated 1Cr12Ni2WMoVNb steel by laser melting deposition

    Institute of Scientific and Technical Information of China (English)

    Wang Yudai; Tang Haibo; Fang Yanli; Wang Huaming

    2013-01-01

    Laser melting deposition was carried out to deposit a 1Cr12Ni2WMoVNb steel bar on a wrought bar of same material.Room-temperature tensile properties of the hybrid fabricated 1Cr1 2Ni2WMoVNb steel sample were evaluated,and microstructure,fracture surface morphology,and hardness profile were analyzed by an optical microscope (OM),a scanning electron microscope (SEM),and a hardness tester.Results show that the hybrid fabricated 1Cr12Ni2WMoVNb steel sample consists of laser deposited zone,wrought substrate zone,and heat affected zone (HAZ)of the wrought substrate.The laser deposited zone has coarse columnar prior austenite grains and fine well-aligned dendritic structure,while the HAZ of the wrought substrate has equiaxed prior austenite grains which are notably finer than those in the wrought substrate zone.Besides,austenitic transformation mechanism of the HAZ of the wrought substrate is different from that of the laser deposited zone during the reheating period of the laser deposition,which determines the different prior austenite grain morphologies of the two zones.Microhardness values of both the laser deposited zone and the HAZ of the wrought substrate are higher than that of the wrought substrate zone.Tensile properties of the hybrid fabricated 1Cr12Ni2WMoVNb steel sample are comparable to those of the wrought bar,and fracture occurs in the wrought substrate zone during the tensile test.

  3. Hybrid silicon evanescent devices

    Directory of Open Access Journals (Sweden)

    Alexander W. Fang

    2007-07-01

    Full Text Available Si photonics as an integration platform has recently been a focus of optoelectronics research because of the promise of low-cost manufacturing based on the ubiquitous electronics fabrication infrastructure. The key challenge for Si photonic systems is the realization of compact, electrically driven optical gain elements. We review our recent developments in hybrid Si evanescent devices. We have demonstrated electrically pumped lasers, amplifiers, and photodetectors that can provide a low-cost, scalable solution for hybrid integration on a Si platform by using a novel hybrid waveguide architecture, consisting of III-V quantum wells bonded to Si waveguides.

  4. Hybrid Baryons

    CERN Document Server

    Page, P R

    2003-01-01

    We review the status of hybrid baryons. The only known way to study hybrids rigorously is via excited adiabatic potentials. Hybrids can be modelled by both the bag and flux-tube models. The low-lying hybrid baryon is N 1/2^+ with a mass of 1.5-1.8 GeV. Hybrid baryons can be produced in the glue-rich processes of diffractive gamma N and pi N production, Psi decays and p pbar annihilation.

  5. Determination of the electronic, dielectric, and optical properties of sillenite Bi12TiO20 and perovskite-like Bi4Ti3O12 materials from hybrid first-principle calculations

    KAUST Repository

    Lardhi, Sheikha F.

    2016-04-05

    Density functional theory calculation was conducted to determine the optoelectronic properties of bismuthtitanate sillenite (Bi12TiO20) and perovskite-like (Bi4Ti3O12) structures. The lattice parameters were experimentally obtained from Rietveld analysis. The density functional perturbation theory approach was used with the standard Perdew–Burke–Ernzerhof functional and screened Coulomb hybrid Heyd–Scuseria–Ernzerhof functional to investigate the electronic structure and absorption coefficient. Both compounds have good carrier transport properties, low effective hole and electron masses, high dielectric constant, and low exciton binding energy.

  6. High-Pressure Single-Crystal Structures of 3D Lead-Halide Hybrid Perovskites and Pressure Effects on their Electronic and Optical Properties.

    Science.gov (United States)

    Jaffe, Adam; Lin, Yu; Beavers, Christine M; Voss, Johannes; Mao, Wendy L; Karunadasa, Hemamala I

    2016-04-27

    We report the first high-pressure single-crystal structures of hybrid perovskites. The crystalline semiconductors (MA)PbX3 (MA = CH3NH3 (+), X = Br(-) or I(-)) afford us the rare opportunity of understanding how compression modulates their structures and thereby their optoelectronic properties. Using atomic coordinates obtained from high-pressure single-crystal X-ray diffraction we track the perovskites' precise structural evolution upon compression. These structural changes correlate well with pressure-dependent single-crystal photoluminescence (PL) spectra and high-pressure bandgaps derived from density functional theory. We further observe dramatic piezochromism where the solids become lighter in color and then transition to opaque black with compression. Indeed, electronic conductivity measurements of (MA)PbI3 obtained within a diamond-anvil cell show that the material's resistivity decreases by 3 orders of magnitude between 0 and 51 GPa. The activation energy for conduction at 51 GPa is only 13.2(3) meV, suggesting that the perovskite is approaching a metallic state. Furthermore, the pressure response of mixed-halide perovskites shows new luminescent states that emerge at elevated pressures. We recently reported that the perovskites (MA)Pb(Br x I1-x )3 (0.2 solar cells employing these absorbers. Our high-pressure PL data indicate that compression can mitigate this PL redshift and may afford higher steady-state voltages from these absorbers. These studies show that pressure can significantly alter the transport and thermodynamic properties of these technologically important semiconductors.

  7. Selective sequential separation of ABS/HIPS and PVC from automobile and electronic waste shredder residue by hybrid nano-Fe/Ca/CaO assisted ozonisation process.

    Science.gov (United States)

    Mallampati, Srinivasa Reddy; Lee, Byoung Ho; Mitoma, Yoshiharu; Simion, Cristian

    2017-02-01

    The separation of plastics containing brominated flame retardants (BFR) like (acrylonitrile-butadiene-styrene (ABS), high-impact polystyrene (HIPS), and polyvinyl chloride (PVC)) from automobile and electronic waste shredder residue (ASR/ESR) are a major concern for thermal recycling. In laboratory scale tests using a hybrid nano-Fe/Ca/CaO assisted ozonation treatment has been found to selectively hydrophilize the surface of ABS/HIPS and PVC plastics, enhancing ABS wettability and thereby promoting its separation from ASR/ESR by means of froth flotation. The water contact angles, of ABS/HIPS and PVC decreased, about 18.7°, 18.3°, and 17.9° in ASR and about 21.2°, 20.7°, and 20.0° in ESR respectively. SEM-EDS, FT-IR, and XPS analyses demonstrated a marked decrease in [Cl] and a significant increase in the number of hydrophilic groups, such as CO, CO, and (CO)O, on the PVC or ABS surface. Under froth flotation conditions at 50rpm, about 99.1% of combined fraction of ABS/HIPS in ASR samples and 99.6% of ABS/HIPS in ESR samples were separated as settled fraction. After separation, the purity of the recovered combined ABS/HIPS fraction was 96.5% and 97.6% in ASR and ESR samples respectively. Furthermore, at 150rpm a 100% PVC separation in the settled fraction, with 98% and 99% purity in ASR and ESR plastics, respectively. Total recovery of non-ABS/HIPS and PVC plastics reached nearly 100% in the floating fraction. Further, this process improved the quality of recycled ASR/ESR plastics by removing surface contaminants or impurities.

  8. Behavioure of high energy electrons on tokamak with low hybrid current drive%托卡马克中低杂波电流驱动下高能电子行为分析

    Institute of Scientific and Technical Information of China (English)

    竹锦霞

    2016-01-01

    Fast electrons and runaway electrons constitute the high-energy tail of electron maxwell distribution during low hy-brid current drive. High energy fast electron can effectively carry current driving to achieve no-induced current drive due to low collision frequency. But under certain conditions,fast electron can turn into runaway electron. It will damage to the device first wall material. This paper studies fast electron distribution and the runaway electrons generation by means of fast electron bremsstrahlung array and runaway electron diagnose. The conversion phenomenon from fast electron to runaway electron can be analyzed.%在低杂波电流驱动下,快电子和逃逸电子构成了非麦克斯韦电子分布的高能尾部。高能快电子由于低的碰撞频率可以有效的携带电流来实现非感应电流驱动。但是在一定条件下,快电子可以转化为高能逃逸电子,这将对装置第一壁材料造成损伤。本文利用快电子轫致辐射测量以及逃逸电子诊断系统研究了低杂波电流驱动下快电子分布和逃逸电子的产生,并分析了快电子转化为逃逸电子的现象。

  9. Observation of a pressure-induced As-As hybridization associated with a change in the electronic state of Fe in the tetragonal phase of EuFe2As2.

    Science.gov (United States)

    Kobayashi, Hisao; Ikeda, Shugo; Sakaguchi, Yui; Yoda, Yoshitaka; Nakamura, Hiroki; Machida, Masahiko

    2013-01-16

    The electronic and vibrational properties of EuFe(2)As(2) in the tetragonal phase between 0 and 5 GPa have been investigated using (57)Fe Mössbauer spectroscopy and (57)Fe nuclear resonance inelastic scattering, respectively. We find a discontinuous increase of the center shift around 2.3 GPa, reflecting a change of the electronic state of Fe, and above 2.5 GPa a softening of the optical phonon modes associated with an increase of the relative volume of the FeAs(4) tetrahedron in the unit cell. Our findings reveal that an effective As-As hybridization along the c axis appears at approximately 2.3 GPa in the tetragonal phase of EuFe(2)As(2), along with a change in the electronic state of Fe, causing bulk superconductivity to appear at a low temperature. Consequently, the change in the electronic state of the Fe atom and the effective As-As hybridization play key roles in the pressure-induced superconductivity in the tetragonal phase of AFe(2)As(2).

  10. Deciphering igneous and metamorphic events in high-grade rocks of the Wilmington complex, Delaware: Morphology, cathodoluminescence and backscattered electron zoning, and SHRIMP U-Pb geochronology of zircon and monazite

    Science.gov (United States)

    Aleinikoff, J.N.; Schenck, W.S.; Plank, M.O.; Srogi, L.A.; Fanning, C.M.; Kamo, S.L.; Bosbyshell, H.

    2006-01-01

    High-grade rocks of the Wilmington Complex, northern Delaware and adjacent Maryland and Pennsylvania, contain morphologically complex zircons that formed through both igneous and metamorphic processes during the development of an island-arc complex and suturing of the arc to Laurentia. The arc complex has been divided into several members, the protoliths of which include both intrusive and extrusive rocks. Metasedimentary rocks are interlayered with the complex and are believed to be the infrastructure upon which the arc was built. In the Wilmingto n Complex rocks, both igneous and metamorphic zircons occur as elongate and equant forms. Chemical zoning, shown by cathodoluminescence (CL), includes both concentric, oscillatory patterns, indicative of igneous origin, and patchwork and sector patterns, suggestive of metamorphic growth. Metamorphic monazites are chemically homogeneous, or show oscillatory or spotted chemical zoning in backscattered electron images. U-Pb geochronology by sensitive high resolution ion microprobe (SHRIMP) was used to date complexly zoned zircon and monazite. All but one member of the Wilmington Complex crystallized in the Ordovician between ca. 475 and 485 Ma; these rocks were intruded by a suite of gabbro-to-granite plutonic rocks at 434 ?? Ma. Detrital zircons in metavolcanic and metasedimentary units were derived predominantly from 0.9 to 1.4 Ga (Grenvillian) basement, presumably of Laurentian origin. Amphibolite to granulite facies metamorphism of the Wilmington Complex, recorded by ages of metamorphic zircon (428 ?? 4 and 432 ?? 6 Ma) and monazite (429 ?? 2 and 426 ?? 3 Ma), occurred contemporaneously with emplacement of the younger plutonic rocks. On the basis of varying CL zoning patterns and external morphologies, metamorphic zircons formed by different processes (presumably controlled by rock chemistry) at slightly different times and temperatures during prograde metamorphism. In addition, at least three other thermal episodes are

  11. Van der Waals-coupled electronic states in incommensurate double-walled carbon nanotubes

    Science.gov (United States)

    Liu, Kaihui; Jin, Chenhao; Hong, Xiaoping; Kim, Jihoon; Zettl, Alex; Wang, Enge; Wang, Feng

    2014-10-01

    Non-commensurate two-dimensional materials such as a twisted graphene bilayer or graphene on boron nitride, consisting of components that have no finite common unit cell, exhibit emerging moiré physics such as novel Van Hove singularities, Fermi velocity renormalization, mini Dirac points and Hofstadter butterflies. Here we use double-walled carbon nanotubes as a model system for probing moiré physics in incommensurate one-dimensional systems, by combining structural and optical characterizations. We show that electron wavefunctions between incommensurate inner- and outer-wall nanotubes can hybridize strongly, contrary to the conventional wisdom of negligible electron hybridization due to destructive interference. The chirality-dependent inter-tube electronic coupling is described by one-dimensional zone folding of the electronic structure of twisted-and-stretched graphene bilayers. Our results demonstrate that incommensurate van der Waals interactions can be important for engineering the electronic structure and optical properties of one-dimensional materials.

  12. Hybrid vehicles

    Energy Technology Data Exchange (ETDEWEB)

    West, J.G.W. [Electrical Machines (United Kingdom)

    1997-07-01

    The reasons for adopting hybrid vehicles result mainly from the lack of adequate range from electric vehicles at an acceptable cost. Hybrids can offer significant improvements in emissions and fuel economy. Series and parallel hybrids are compared. A combination of series and parallel operation would be the ideal. This can be obtained using a planetary gearbox as a power split device allowing a small generator to transfer power to the propulsion motor giving the effect of a CVT. It allows the engine to run at semi-constant speed giving better fuel economy and reduced emissions. Hybrid car developments are described that show the wide range of possible hybrid systems. (author)

  13. Hybrid codes: Methods and applications

    Energy Technology Data Exchange (ETDEWEB)

    Winske, D. (Los Alamos National Lab., NM (USA)); Omidi, N. (California Univ., San Diego, La Jolla, CA (USA))

    1991-01-01

    In this chapter we discuss hybrid'' algorithms used in the study of low frequency electromagnetic phenomena, where one or more ion species are treated kinetically via standard PIC methods used in particle codes and the electrons are treated as a single charge neutralizing massless fluid. Other types of hybrid models are possible, as discussed in Winske and Quest, but hybrid codes with particle ions and massless fluid electrons have become the most common for simulating space plasma physics phenomena in the last decade, as we discuss in this paper.

  14. Hybrid Si/TMD 2D electronic double channels fabricated using solid CVD few-layer-MoS2 stacking for Vth matching and CMOS-compatible 3DFETs

    KAUST Repository

    Chen, Min Cheng

    2014-12-01

    Stackable 3DFETs such as FinFET using hybrid Si/MoS2 channels were developed using a fully CMOS-compatible process. Adding several molecular layers (3-16 layers) of the transition-metal dichalcogenide (TMD), MoS2 to Si fin and nanowire resulted in improved (+25%) Ion,n of the FinFET and nanowire FET (NWFET). The PFETs also operated effectively and the N/P device Vth are low and matched perfectly. The proposed heterogeneous Si/TMD 3DFETs can be useful in future electronics. © 2014 IEEE.

  15. GW quasiparticle band gap of the hybrid organic-inorganic perovskite CH$_3$NH$_3$PbI$_3$: Effect of spin-orbit interaction, semicore electrons, and self-consistency

    OpenAIRE

    Filip, Marina R.; Giustino, Feliciano

    2014-01-01

    We study the quasiparticle band gap of the hybrid organic-inorganic lead halide perovskite CH$_3$NH$_3$PbI$_3$, using many-body perturbation theory based on the $GW$ approximation. We perform a systematic analysis of the band gap sensitivity to relativistic spin-orbit effects, to the description of semicore Pb-5$d$ and I-4$d$ electrons, and to the starting Kohn-Sham eigenvalues. We find that the inclusion of semicore states increases the calculated band gap by 0.2 eV, and self-consistency on ...

  16. Printed hybrid systems

    Science.gov (United States)

    Karioja, Pentti; Mäkinen, Jukka-Tapani; Keränen, Kimmo; Aikio, Janne; Alajoki, Teemu; Jaakola, Tuomo; Koponen, Matti; Keränen, Antti; Heikkinen, Mikko; Tuomikoski, Markus; Suhonen, Riikka; Hakalahti, Leena; Kopola, Pälvi; Hast, Jukka; Liedert, Ralf; Hiltunen, Jussi; Masuda, Noriyuki; Kemppainen, Antti; Rönkä, Kari; Korhonen, Raimo

    2012-04-01

    This paper presents research activities carried out at VTT Technical Research Centre of Finland in the field of hybrid integration of optics, electronics and mechanics. Main focus area in our research is the manufacturing of electronic modules and product structures with printed electronics, film-over-molding and polymer sheet lamination technologies and the goal is in the next generation of smart systems utilizing monolithic polymer packages. The combination of manufacturing technologies such as roll-to-roll -printing, injection molding and traditional component assembly is called Printed Hybrid Systems (PHS). Several demonstrator structures have been made, which show the potential of polymer packaging technology. One demonstrator example is a laminated structure with embedded LED chips. Element thickness is only 0.3mm and the flexible stack of foils can be bent in two directions after assembly process and was shaped curved using heat and pressure. The combination of printed flexible circuit boards and injection molding has also been demonstrated with several functional modules. The demonstrators illustrate the potential of origami electronics, which can be cut and folded to 3D shapes. It shows that several manufacturing process steps can be eliminated by Printed Hybrid Systems technology. The main benefits of this combination are small size, ruggedness and conformality. The devices are ideally suited for medical applications as the sensitive electronic components are well protected inside the plastic and the structures can be cleaned easily due to the fact that they have no joints or seams that can accumulate dirt or bacteria.

  17. Analog and hybrid computing

    CERN Document Server

    Hyndman, D E

    2013-01-01

    Analog and Hybrid Computing focuses on the operations of analog and hybrid computers. The book first outlines the history of computing devices that influenced the creation of analog and digital computers. The types of problems to be solved on computers, computing systems, and digital computers are discussed. The text looks at the theory and operation of electronic analog computers, including linear and non-linear computing units and use of analog computers as operational amplifiers. The monograph examines the preparation of problems to be deciphered on computers. Flow diagrams, methods of ampl

  18. Multi-MHz time-of-flight electronic bandstructure imaging of graphene on Ir(111)

    Energy Technology Data Exchange (ETDEWEB)

    Tusche, C., E-mail: c.tusche@fz-juelich.de [Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Peter Grünberg Institut (PGI-6), Forschungszentrum Jülich GmbH, 52425 Jülich (Germany); Goslawski, P.; Engel, D.; Jankowiak, A. [Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, 12489 Berlin (Germany); Kutnyakhov, D.; Elmers, H. J.; Chernov, S.; Wallauer, R.; Schönhense, G. [Institut für Physik, Johannes Gutenberg-Universität, 55128 Mainz (Germany); Ellguth, M. [Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany); Institut für Physik, Johannes Gutenberg-Universität, 55128 Mainz (Germany); Medjanik, K. [Institut für Physik, Johannes Gutenberg-Universität, 55128 Mainz (Germany); MAX IV Laboratory, Ole Römers vag 1, 22363 Lund (Sweden)

    2016-06-27

    In the quest for detailed spectroscopic insight into the electronic structure at solid surfaces in a large momentum range, we have developed an advanced experimental approach. It combines the 3D detection scheme of a time-of-flight momentum microscope with an optimized filling pattern of the BESSY II storage ring. Here, comprehensive data sets covering the full surface Brillouin zone have been used to study faint substrate-film hybridization effects in the electronic structure of graphene on Ir(111), revealed by a pronounced linear dichroism in angular distribution. The method paves the way to 3D electronic bandmapping with unprecedented data recording efficiency.

  19. The neural elements in the lining of the ventricular-subventricular zone: making an old story new by high-resolution scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Carlos Alexandre Dos Santos Haemmerle

    2015-10-01

    Full Text Available The classical description of the neural elements that compose the lining of brain ventricles introduces us to the single layer of ependymal cells. However, new findings, especially in the lateral ventricle - the major niche for the generation of new neurons in the adult brain - have provided information about additional cell elements that influence the organization of this part of the ventricular system and produce important contributions to neurogenesis. To complement the cell neurochemistry findings, we present a three-dimensional in situ description that demonstrates the anatomical details of the different types of ciliated cells and the innervation of these elements. After processing adult rat brains for ultrastructural analysis by high-resolution scanning electron microscopy and transmission electron microscopy, we observed a heterogeneous pattern of cilia distribution at the different poles of the lateral ventricle surface. Furthermore, we describe the particular three-dimensional aspects of the ciliated cells of the lateral ventricle, in addition the fiber bundles and varicose axons surrounding these cells. Therefore, we provide a unique ultrastructural description of the three-dimensional in situ organization of the lateral ventricle surface, highlighting its innervation, to corroborate the available neurochemical and functional findings regarding the factors that regulate this neurogenic niche.

  20. The neural elements in the lining of the ventricular-subventricular zone: making an old story new by high-resolution scanning electron microscopy.

    Science.gov (United States)

    Haemmerle, Carlos Alexandre Dos Santos; Nogueira, Maria Inês; Watanabe, Ii-Sei

    2015-01-01

    The classical description of the neural elements that compose the lining of brain ventricles introduces us to the single layer of ependymal cells. However, new findings, especially in the lateral ventricle (LV)-the major niche for the generation of new neurons in the adult brain-have provided information about additional cell elements that influence the organization of this part of the ventricular system and produce important contributions to neurogenesis. To complement the cell neurochemistry findings, we present a three-dimensional in situ description that demonstrates the anatomical details of the different types of ciliated cells and the innervation of these elements. After processing adult rat brains for ultrastructural analysis by high-resolution scanning electron microscopy (HRSEM) and transmission electron microscopy, we observed a heterogeneous pattern of cilia distribution at the different poles of the LV surface. Furthermore, we describe the particular three-dimensional aspects of the ciliated cells of the LV, in addition the fiber bundles and varicose axons surrounding these cells. Therefore, we provide a unique ultrastructural description of the three-dimensional in situ organization of the LV surface, highlighting its innervation, to corroborate the available neurochemical and functional findings regarding the factors that regulate this neurogenic niche.

  1. Mastering the Gray Zone: Understanding a Changing Era of Conflict

    Science.gov (United States)

    2015-12-01

    origins and engines of such strategies. But it is important to recognize some of the potential ana - lytical challenges with this category. 14 To...new emphasis on gray zone strategies. HYBRID WARFARE One leading proponent of this concept, scholar Frank Hoffman, defines hybrid threats as “Any...on guerrilla tactics but is a fascinating and im- pressive survey. 3. Cited in Frank Hoffman, “On Not-So-New Warfare: Politi- cal Warfare vs. Hybrid

  2. A hybrid classical-quantum approach for ultra-scaled confined nanostructures : modeling and simulation*

    Directory of Open Access Journals (Sweden)

    Pietra Paola

    2012-04-01

    Full Text Available We propose a hybrid classical-quantum model to study the motion of electrons in ultra-scaled confined nanostructures. The transport of charged particles, considered as one dimensional, is described by a quantum effective mass model in the active zone coupled directly to a drift-diffusion problem in the rest of the device. We explain how this hybrid model takes into account the peculiarities due to the strong confinement and we present numerical simulations for a simplified carbon nanotube. Nous proposons un modèle hybride classique-quantique pour décrire le mouvement des électrons dans des nanostructures très fortement confinées. Le transport des particules, consideré unidimensionel, est décrit par un modèle quantique avec masse effective dans la zone active couplé à un problème de dérive-diffusion dans le reste du domaine. Nous expliquons comment ce modèle hybride prend en compte les spécificités de ce très fort confinement et nous présentons des résultats numériques pour un nanotube de carbone simplifié.

  3. Achieving High Strength Joint of Pure Copper Via Laser-Cold Metal Transfer Arc Hybrid Welding

    Science.gov (United States)

    Chen, Yulong; Chen, Cong; Gao, Ming; Zeng, Xiaoyan

    2016-06-01

    Fiber laser-cold metal transfer arc hybrid welding of pure copper was studied. Weld porosity was tested by X-ray nondestructive testing. Microstructure and fracture features were observed by scanning electron microscopy. Mechanical properties were evaluated by cross weld tensile test. Full penetrated and continuous welds were obtained by hybrid welding once the laser power reached 2 kW, while they could not be obtained by laser welding alone, even though the laser power reached 5 kW. The ultimate tensile strength (UTS), the yield strength (YS), and the elongation of the best hybrid weld material were up to 227, 201 MPa, and 21.5 pct, respectively. The joint efficiencies in UTS and YS of hybrid weld were up to 84 and 80 pct of the BM, respectively. The fracture location changes from the fusion zone to the heat-affected zone with the increase of laser power. Besides, the mechanisms of process stability and porosity suppression were clarified by laser-arc interaction and pool behavior. The strengthening mechanism was discussed by microstructure characteristics.

  4. Dispersion Relation Tool for generalized lower-hybrid mode with, density gradient, equilibrium ExB drift, collisions and finite electron Larmor radius

    CERN Document Server

    Romadanov, Ivan; Frias, Winston; Chapurin, Oleksandr; Koshkarov, Oleksandr

    2016-01-01

    MATLAB solver has been developed for studies of local instabilities in partially magnetized plasmas typical for ExB discharge plasmas. Examples for the Simon-Hoh, lower-hybrid and ion-sound instabilities in Penning discharge. The detailed behavior of the local dispersion relation can be investigated, plotted and saved with this solver. It allows to include various effects, change plasma parameters and obtain eigen-frequencies as a function of the wavenumbers in x or y directions.

  5. ISOLDE target zone control room

    CERN Multimedia

    2016-01-01

    Operating the ISOLDE target handling robots from the dedicated control room in building 197. Monitors showing the movements of the robots (GPS in this case) in the target zone. The footage shows the actual operation by the operator as well as the different equipment such as camera electronics, camera motor controls, camera monitors and Kuka robot controls touch panel.

  6. Hybrid Metaheuristics

    CERN Document Server

    2013-01-01

    The main goal of this book is to provide a state of the art of hybrid metaheuristics. The book provides a complete background that enables readers to design and implement hybrid metaheuristics to solve complex optimization problems (continuous/discrete, mono-objective/multi-objective, optimization under uncertainty) in a diverse range of application domains. Readers learn to solve large scale problems quickly and efficiently combining metaheuristics with complementary metaheuristics, mathematical programming, constraint programming and machine learning. Numerous real-world examples of problems and solutions demonstrate how hybrid metaheuristics are applied in such fields as networks, logistics and transportation, bio-medical, engineering design, scheduling.

  7. A Comparative Analysis of Different Finishing and Polishing Devices on Nanofilled, Microfilled, and Hybrid Composite: A Scanning Electron Microscopy and Profilometric Study.

    Science.gov (United States)

    Yadav, Rishi D; Raisingani, Deepak; Jindal, Divya; Mathur, Rachit

    2016-01-01

    The continuous development of esthetically acceptable adhesive restorative material has made a variety of tooth-colored materials available for clinical use. The advent of visible light polymerizing resin and the use of finer filler particles permit resin composites to be polished to higher degree. The effect of polishing systems on surface finish has been reported to be material-dependent, and the effectiveness of these systems was mostly product-dependent. Hence, the purpose of this study was to evaluate the efficiency of finishing and polishing systems on the surface roughness of nanofilled, microfilled, and hybrid composite restorative materials available in the market.

  8. Effect of p–d hybridization, structural distortion and cation electronegativity on electronic properties of ZnSnX{sub 2} (X=P, As, Sb) chalcopyrite semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Mishra, S. [National Institute of Technology, Rourkela 769008, Odisha (India); Ganguli, B., E-mail: biplabg@nitrkl.ac.in [National Institute of Technology, Rourkela 769008, Odisha (India)

    2013-04-15

    Significant effects of p–d hybridization, structural distortion and cation-electro-negativity are found on band gap in ZnSnX{sub 2} (X=P, As, Sb). Our study suggests these compounds to be direct band gap semiconductors with band gaps of 1.23, 0.68 and 0.19 eV respectively. Lattice constants, tetragonal distortion (η), anion displacement, bond lengths and bulk moduli are calculated by Density Functional Theory based on Tight binding Linear Muffin-Tin orbital method. Our result of structural properties is in good agreement with the available experimental and other theoretical results. Calculated band gaps also agree well with the experimental works within LDA limitation. Unlike other semiconductors in the group II–IV–V{sub 2}, there is a reduction in the band gap of 0.22, 0.20 and 0.24 eV respectively in ZnSnX{sub 2} (X=P, As, Sb) due to p–d hybridization. Structural distortion decreases band gap by 0.20, 0.12 and 0.10 eV respectively. We find that cation electronegativity effect is responsible for increasing the band gap relative to their binary analogs GaInP{sub 2}, InGaAs{sub 2} and GaInSb{sub 2} respectively and increment are 0.13, 0.04 and 0.13 eV respectively. - Graphical abstract: One unit cell of ZnSnX{sub 2} (X=P, As, Sb) chalcopyrite semiconductor. Semiconductors ZnSnX{sub 2} (X=P, As, Sb) are found to be direct band gap semiconductors with band gaps 1.23, 0.68 and 0.19 eV respectively. The quantitative estimate of effects of p–d hybridization, structural distortion and cation electronegativity shows band gaps change significantly due to these effects. Highlights: ► ZnSnX{sub 2} (X=P, As, Sb) are direct band gap semiconductors. ► These have band gaps of 1.23 eV, 0.68 eV and 0.19 eV respectively. ► The band gap reduction due to p–d hybridization is 13.41%, 18.51% and 40% respectively. ► Band gap reduction due to structural distortion is 12.12%, 11.11% and 16.66% respectively. ► Band gap increases 8.38%, 3.70% and 21.31% respectively

  9. Hybrid intermediaries

    OpenAIRE

    Cetorelli, Nicola

    2014-01-01

    I introduce the concept of hybrid intermediaries: financial conglomerates that control a multiplicity of entity types active in the "assembly line" process of modern financial intermediation, a system that has become known as shadow banking. The complex bank holding companies of today are the best example of hybrid intermediaries, but I argue that financial firms from the "nonbank" space can just as easily evolve into conglomerates with similar organizational structure, thus acquiring the cap...

  10. Hybrid composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available effect was observed for the elongation at break of the hybrid composites. The impact strength of the hybrid composites increased with the addition of glass fibres. The tensile and impact properties of thermoplastic natural rubber reinforced short... panels made from conventional structural materials. Figure 3 illustrates the performance of cellular biocomposite panels against conventional systems used for building and residential construction, namely a pre- cast pre-stressed hollow core concrete...

  11. Zoning Districts, Zoning, Published in 2002, Freelance.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Zoning Districts dataset, was produced all or in part from Hardcopy Maps information as of 2002. It is described as 'Zoning'. Data by this publisher are often...

  12. Alleviating Surface Degradation of Nickel-Rich Layered Oxide Cathode Material by Encapsulating with Nanoscale Li-Ions/Electrons Superionic Conductors Hybrid Membrane for Advanced Li-Ion Batteries.

    Science.gov (United States)

    Li, Lingjun; Xu, Ming; Yao, Qi; Chen, Zhaoyong; Song, Liubin; Zhang, Zhian; Gao, Chunhui; Wang, Peng; Yu, Ziyang; Lai, Yanqing

    2016-11-16

    Nickel-rich layered oxide cathode materials for advanced lithium-ion batteries have received much attention recently because of their high specific capacities and significant reduction of cost. However, these cathodes are facing a fundamental challenge of loss in performance as a result of surface lithium residue, side reactions with the electrolyte and structure rearrangement upon long-term cycling. Herein, by capturing the lithium residue on the surface of LiNi0.8Co0.1Mn0.1O2 (NCM) cathode material as Li source, we propose a hybrid coating strategy incorporating lithium ions conductor LixAlO2 with superconductor LixTi2O4 to overcome those obstinate issues. By taking full advantage of this unique hybrid nanomembrane coating architecture, both the lithium ion diffusion ability and electronic conductivity of LiNi0.8Co0.1Mn0.1O2 cathode material are improved, resulting in remarkably enhanced electrochemical performances during high voltage operation, including good cycle performance, high reversible capacity, and excellent rate capability. A high initial discharge capacity of 227 mAh g(-1) at 4.4 V cutoff voltage with Coulombic efficiency of 87.3%, and reversible capacity of 200 mAh g(-1) with 98% capacity retention after 100 cycles at a current density of 0.5 C can be attained. The improved electrochemical performance can be attributed to the synergetic contribution from the removal of lithium residues and the unique hybrid nanomembrane coating architecture. Most importantly, this surface modification technique could save some cost, simplify the technical procedure, and show great potential to optimize battery performance, apply in a large scale and extend to all nickel-rich cathode material.

  13. A Hybrid Solid-State NMR and Electron Microscopy Structure-Determination Protocol for Engineering Advanced para-Crystalline Optical Materials.

    Science.gov (United States)

    Thomas, Brijith; Rombouts, Jeroen; Oostergetel, Gert T; Gupta, Karthick B S S; Buda, Francesco; Lammertsma, Koop; Orru, Romano; de Groot, Huub J M

    2017-03-08

    Hybrid magic-angle spinning (MAS) NMR spectroscopy and TEM were demonstrated for de novo structure determination of para-crystalline materials with a bioinspired fused naphthalene diimide (NDI)-salphen-phenazine prototype light-harvesting compound. Starting from chiral building blocks with C2 molecular symmetry, the asymmetric unit was determined by MAS NMR spectroscopy, index low-resolution TEM diffraction data, and resolve reflection conditions, and for the first time the ability to determine the space group from reciprocal space data using this hybrid approach was shown. Transfer of molecular C2 symmetry into P2/c packing symmetry provided a connection across length scales to overcome both lack of long-range order and missing diffraction-phase information. Refinement with heteronuclear distance constraints confirmed the racemic P2/c packing that was scaffolded by molecular recognition of salphen zinc in a pseudo-octahedral environment with bromide and with alkyl chains folding along the phenazine. The NDI light-harvesting stacks ran orthogonal to the intermolecular electric dipole moment present in the solid. Finally, the orientation of flexible lamellae on an electrode surface was determined. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  14. Additive Manufacturing of Hybrid Circuits

    Science.gov (United States)

    Sarobol, Pylin; Cook, Adam; Clem, Paul G.; Keicher, David; Hirschfeld, Deidre; Hall, Aaron C.; Bell, Nelson S.

    2016-07-01

    There is a rising interest in developing functional electronics using additively manufactured components. Considerations in materials selection and pathways to forming hybrid circuits and devices must demonstrate useful electronic function; must enable integration; and must complement the complex shape, low cost, high volume, and high functionality of structural but generally electronically passive additively manufactured components. This article reviews several emerging technologies being used in industry and research/development to provide integration advantages of fabricating multilayer hybrid circuits or devices. First, we review a maskless, noncontact, direct write (DW) technology that excels in the deposition of metallic colloid inks for electrical interconnects. Second, we review a complementary technology, aerosol deposition (AD), which excels in the deposition of metallic and ceramic powder as consolidated, thick conformal coatings and is additionally patternable through masking. Finally, we show examples of hybrid circuits/devices integrated beyond 2-D planes, using combinations of DW or AD processes and conventional, established processes.

  15. A simple approach to obtain hybrid Au-loaded polymeric nanoparticles with a tunable metal load† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06850a Click here for additional data file.

    Science.gov (United States)

    Luque-Michel, Edurne; Larrea, Ane; Lahuerta, Celia; Imbuluzqueta, Edurne; Arruebo, Manuel; Santamaría, Jesús

    2016-01-01

    A new strategy to nanoengineer multi-functional polymer–metal hybrid nanostructures is reported. By using this protocol the hurdles of most of the current developments concerning covalent and non-covalent attachment of polymers to preformed inorganic nanoparticles (NPs) are overcome. The strategy is based on the in situ reduction of metal precursors using the polymeric nanoparticle as a nanoreactor. Gold nanoparticles and poly(dl-lactic-co-glycolic acid), PLGA, are located in the core and shell, respectively. This novel technique enables the production of PLGA NPs smaller than 200 nm that bear either a single encapsulated Au NP or several smaller NPs with tunable sizes and a 100% loading efficiency. In situ reduction of Au ions inside the polymeric NPs was achieved on demand by using heat to activate the reductive effect of citrate ions. In addition, we show that the loading of the resulting Au NPs inside the PLGA NPs is highly dependent on the surfactant used. Electron microscopy, laser irradiation, UV-Vis and fluorescence spectroscopy characterization techniques confirm the location of Au nanoparticles. These promising results indicate that these hybrid nanomaterials could be used in theranostic applications or as contrast agents in dark-field imaging and computed tomography. PMID:26612770

  16. Effect of additional electron acceptor in hybrid P3HT:PCBM:ZnO spin-coated films for photovoltaic application

    CSIR Research Space (South Africa)

    Muller, T

    2016-04-01

    Full Text Available methyl ester (PCBM) blend, and used as additional acceptors of electrons in the active layer. Metal–oxide interface layers between the active layer and ITO and the top contact layer, respectively, were introduced in the solar cell to compensate...

  17. Catalytically-relevant electron transfer between two hemes bL in the hybrid cytochrome bc1-like complex containing a fusion of Rhodobacter sphaeroides and capsulatus cytochromes b.

    Science.gov (United States)

    Czapla, Monika; Cieluch, Ewelina; Borek, Arkadiusz; Sarewicz, Marcin; Osyczka, Artur

    2013-06-01

    To address mechanistic questions about the functioning of dimeric cytochrome bc1 new genetic approaches have recently been developed. They were specifically designed to enable construction of asymmetrically-mutated variants suitable for functional studies. One approach exploited a fusion of two cytochromes b that replaced the separate subunits in the dimer. The fusion protein, built from two copies of the same cytochrome b of purple bacterium Rhodobacter capsulatus, served as a template to create a series of asymmetrically-mutated cytochrome bc1-like complexes (B-B) which, through kinetic studies, disclosed several important principles of dimer engineering. Here, we report on construction of another fusion protein complex that adds a new tool to investigate dimeric function of the enzyme through the asymmetrically mutated forms of the protein. This complex (BS-B) contains a hybrid protein that combines two different cytochromes b: one coming from R. capsulatus and the other - from a closely related species, R. sphaeroides. With this new fusion we addressed a still controversial issue of electron transfer between the two hemes bL in the core of dimer. Kinetic data obtained with a series of BS-B variants provided new evidence confirming the previously reported observations that electron transfer between those two hemes occurs on a millisecond timescale, thus is a catalytically-relevant event. Both types of the fusion complexes (B-B and BS-B) consistently implicate that the heme-bL-bL bridge forms an electronic connection available for inter-monomer electron transfer in cytochrome bc1. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Effect of Weld Characteristic on Mechanical Strength of Laser-Arc Hybrid-Welded Al-Mg-Si-Mn Aluminum Alloy

    Science.gov (United States)

    Zhang, Chen; Gao, Ming; Jiang, Ming; Zeng, Xiaoyan

    2016-11-01

    Laser-arc hybrid welding (LAHW) was employed to improve the tensile properties of the joints of 8-mm-thick Al-Mg-Si-Mn alloy (AA6082) using Al-5Mg filler wire. The weld microstructures were examined by scanning electron microscope, electron backscattered diffraction, and transmission electron microscopy in detail. The LAHW joints with pore-free and high-tensile performances were obtained. The strength enhancement of the fusion zone and heat-affected zone in the LAHW joint was mainly attributed to the grain refinement strengthening and the precipitation strengthening, respectively. The microstructure characteristics were related to the effects of laser-arc interaction on the energy transfer within the molten pool. The arc caused the majority of laser energy to dissipate out of the keyhole, and then it reduced the heat input. The lower heat input refined the grain size, weakened the overaging effect, and thus improved the tensile strength.

  19. Electronic, magnetic and optical properties of reduced hybrid layered complex Ni(pyz)V4O10 (pyz=C4H4N2) by first-principles

    Science.gov (United States)

    Munir, Junaid; Mat Isa, Ahmad Radzi; Yousaf, Masood; Aliabad, H. A. Rahnamaye; Ain, Qurat-ul; Saeed, M. A.

    2016-10-01

    This article reports the electronic, structure, magnetic and optical properties of reduced hybrid layered complex Ni(pyz)V4O10 (pyz=C4H4N2) studied by employing density functional theory with local density approximation (LDA), generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof-96 (PBE) and modified Becke-Johnson (mBJ) exchange-correlation potential and energy. The band structure and density of states of these compounds are also presented. The total density of states (DOS) for up and down spin states clearly split, which means that the exchange interaction causes the ordered spin arrangement. PBE-mBJ calculation reveals a wider band gap in spin down state, which shows a half-metallic electronic character at the equilibrium state. The spin-polarized calculations indicate metallic nature in orthorhombic crystalline phase. It is also noted that the optical conductivity for PBE-mBJ is larger than that of LDA and PBE-GGA. Furthermore, the results show a half-metallic ferromagnetic ground state for Ni(pyz)V4O10 in PBE-mBJ potential. The present results suggest Ni(pyz)V4O10 compound as a potential candidate for the future optoelectronic and spintronic applications.

  20. P-Fluorous Phosphines as Electron-Poor/Fluorous Hybrid Functional Ligands for Precious Metal Catalysts: Synthesis of Rh(I, Ir(I, Pt(II, and Au(I Complexes Bearing P-Fluorous Phosphine Ligands

    Directory of Open Access Journals (Sweden)

    Shin-ichi Kawaguchi

    2017-01-01

    Full Text Available P-Fluorous phosphine (R2PRf, in which the perfluoroalkyl group is directly bonded to the phosphorus atom, is a promising ligand because it has a hybrid functionality, i.e., electron-poor and fluorous ligands. However, examples of P-fluorous phosphine–metal complexes are still rare, most probably because the P-fluorous group is believed to decrease the coordination ability of the phosphines dramatically. In contrast, however, we have succeeded in synthesizing a series of P-fluorous phosphine–coordinated metal complexes such as rhodium, iridium, platinum, and gold. Furthermore, the electronic properties of R2PnC10F21 are investigated by X-ray analysis of PtCl2(Ph2PnC10F212 and the infrared CO stretching frequency of RhCl(CO(R2PnC10F212. IrCl(CO(Ph2PnC10F212- and AuCl(R2PnC10F21-catalyzed reactions are also demonstrated.

  1. The Electronic Structures and Optical Properties of Alkaline-Earth Metals Doped Anatase TiO2: A Comparative Study of Screened Hybrid Functional and Generalized Gradient Approximation

    Directory of Open Access Journals (Sweden)

    Jin-Gang Ma

    2015-08-01

    Full Text Available Alkaline-earth metallic dopant can improve the performance of anatase TiO2 in photocatalysis and solar cells. Aiming to understand doping mechanisms, the dopant formation energies, electronic structures, and optical properties for Be, Mg, Ca, Sr, and Ba doped anatase TiO2 are investigated by using density functional theory calculations with the HSE06 and PBE functionals. By combining our results with those of previous studies, the HSE06 functional provides a better description of electronic structures. The calculated formation energies indicate that the substitution of a lattice Ti with an AEM atom is energetically favorable under O-rich growth conditions. The electronic structures suggest that, AEM dopants shift the valence bands (VBs to higher energy, and the dopant-state energies for the cases of Ca, Sr, and Ba are quite higher than Fermi levels, while the Be and Mg dopants result into the spin polarized gap states near the top of VBs. The components of VBs and dopant-states support that the AEM dopants are active in inter-band transitions with lower energy excitations. As to optical properties, Ca/Sr/Ba are more effective than Be/Mg to enhance absorbance in visible region, but the Be/Mg are superior to Ca/Sr/Ba for the absorbance improvement in near-IR region.

  2. Tuning near-gap electronic structure, interface charge transfer and visible light response of hybrid doped graphene and Ag3PO4 composite: Dopant effects

    CERN Document Server

    He, Chao-Ni; Xu, Liang; Yang, Yin-Cai; Zhou, Bing-Xin; Huang, Gui-Fang; Peng, P; Liu, Wu-Ming

    2015-01-01

    The enhanced photocatalytic performance of doped graphene(GR)/semiconductor nanocomposites have recently been widely observed, but an understanding of the underlying mechanisms behind it is still out of reach. As a model system to study the effect of dopants, we investigate the electronic structures and optical properites of doped GR/Ag3PO4 nanocomposites using the first-principles calculations, demonstrating that the band gap, near-gap electronic structure and interface charge transfer of the doped GR/Ag3PO4(100) composite can be tuned by the dopants. Interestingly, the doping atom and C atoms bonded to dopant become active sites for photocatalysis because they are positively or negatively charged due to the charge redistribution caused by interaction. The dopants can enhance the visible light absorption and photoinduced electrons transfer. We propose that the N atom may be most appropriate doping for the GR/Ag3PO4 photocatalyst. This work can rationalize the available experimental results about N-doped GR-s...

  3. CERN manufactured hybrid photon detectors

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    These hybrid photon detectors (HPDs) produce an electric signal from a single photon. An electron is liberated from a photocathode and accelerated to a silicon pixel array allowing the location of the photon on the cathode to be recorded. The electronics and optics for these devices have been developed in close collaboration with industry. HPDs have potential for further use in astrophysics and medical imaging.

  4. Amorphous Carbon-Boron Nitride Nanotube Hybrids

    Science.gov (United States)

    Kim, Jae Woo (Inventor); Siochi, Emilie J. (Inventor); Wise, Kristopher E. (Inventor); Lin, Yi (Inventor); Connell, John (Inventor)

    2016-01-01

    A method for joining or repairing boron nitride nanotubes (BNNTs). In joining BNNTs, the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures. In repairing BNNTs, the damaged site of the nanotube structure is modified with amorphous carbon deposited by controlled electron beam irradiation to form well bonded hybrid a-C/BNNT structures at the damage site.

  5. Optical Orientation in Ferromagnet/Semiconductor Hybrids

    OpenAIRE

    Korenev, V. L.

    2008-01-01

    The physics of optical pumping of semiconductor electrons in the ferromagnet/semiconductor hybrids is discussed. Optically oriented semiconductor electrons detect the magnetic state of the ferromagnetic film. In turn, the ferromagnetism of the hybrid can be controlled optically with the help of the semiconductor. Spin-spin interactions near the interface ferromagnet/semiconductor play crucial role in the optical readout and the manipulation of ferromagnetism.

  6. Rural Productivity Zones (RPZs) for microenterprises

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, R.D.

    1997-12-01

    In this paper the authors discuss the concept of rural productivity zones (RPZs) which are defined as a business incubator to foster income-producing opportunities for the rural poor. The essential ingredients of such a program include: electric power; business development assistance; office services; and quality work space. The electric power source must be a good quality system, consisting of a diesel/wind/photovoltaic hybrid type system, providing reliable service, with a local maintenance program and a functional load management program.

  7. Hybrid dynamics in a species group of swallowtail butterflies.

    Science.gov (United States)

    Dupuis, J R; Sperling, F A H

    2016-10-01

    Hybrid zones provide unique natural laboratories for studying mechanisms of evolution. But identification and classification of hybrid individuals (F1, F2, backcross, etc.) can be complicated by real population changes over time as well as by use of different marker types, both of which challenge documentation of hybrid dynamics. Here, we use multiple genetic markers (mitochondrial DNA, microsatellites and genomewide single nucleotide polymorphisms) to re-examine population structure in a hybrid zone between two