WorldWideScience

Sample records for junctions areae compositae

  1. [Compositae dermatitis].

    Science.gov (United States)

    Jovanović, Marina; Poljacki, Mirjana

    2003-01-01

    Compositae dermatitis is an allergic contact dermatitis caused by plant species of the Compositae family. The first report of a cutaneous reaction to the Chrysanthemum genus was made by Howe JS in 1887. In 1895 Maiden JH reported about skin lesions among men working with Tagetes minuta. Case reports of contact allergic-ragweed dermatitis appeared in the American literature as early as 1919. The North American feverfew--Parthenium Hysterophorus was brought to India from America in 1956 and it caused thousands of cases of so-called parthenium dermatitis. Ragweed and parthenium dermatitis became prototypes for the classic, so-called "airborne" Compositae dermatitis, that affects primarily exposed skin surfaces, and produces a universal erythroderma. The frequency of contact allergy to Compositae in Europe is higher than previously believed. It occurs most frequently in middle-aged and elderly persons, but also in all age groups. During the two past decades a more equal sex ratio has been established. The prevalence varies from 0.7-1.4% in the general population, up to 4.5% among occupationally exposed persons. Compositae allergy is among the top ten contact sensitivities in Europe. In North Europe plants were the cause of 4.4% cases of occupational allergic contact dermatitis. ETIOLOGY AND PATHOGENESIS: Among cultivated Compositae plants, Chrysanthemum is considered to be a major sensitizer in Europe (60%). Among the edible types, it is lettuce--Lactuca sativa and endive Cichorium endivia (20-30%), and wild-growing feverfew--Tanace--tum parthenium (70-90%), tansy--Tanacetum vulgare (54%), and dandelion--Taraxacum officinale (65%). Sesquiterpene lactones are the main sensitizers of the Compositae family. Other components, thiophenes and acetylenes are said to elicit only phytophotodermatitis, but recent studies have demonstrated that some thiophenes and benzofuran derivates possess not only phototoxic activity, but also sensitizing properties. Photosensitivity is

  2. Compositae dermatitis

    OpenAIRE

    Jovanović Mirjana; Poljački Mirjana N.

    2003-01-01

    Introduction Compositae dermatitis is an allergic contact dermatitis caused by plant species of the Compositae family. The first report of a cutaneous reaction to the Chrysanthemum genus was made by Howe JS in 1887. In 1895 Maiden JH reported about skin lesions among men working with Tagetes minute Case reports of contact allergic-ragweed dermatitis appeared in the American literature as early as 1919. The North American feverfew - Parthenium Hysterophorus was brought to India from America in...

  3. Stability of large-area molecular junctions

    NARCIS (Netherlands)

    Akkerman, Hylke B.; Kronemeijer, Auke J.; Harkema, Jan; van Hal, Paul A.; Smits, Edsger C. P.; de Leeuw, Dago M.; Blom, Paul W. M.

    The stability of molecular junctions is crucial for any application of molecular electronics. Degradation of molecular junctions when exposed to ambient conditions is regularly observed. In this report the stability of large-area molecular junctions under ambient conditions for more than two years

  4. Airborne Compositae dermatitis

    DEFF Research Database (Denmark)

    Christensen, Lars Porskjær; Jakobsen, Henrik Byrial; Paulsen, E.

    1999-01-01

    The air around intact feverfew (Tanacetum parthenium) plants was examined for the presence of airborne parthenolide and other potential allergens using a high-volume air sampler and a dynamic headspace technique. No particle-bound parthenolide was detected in the former. Among volatiles emitted f...... for airborne Compositae dermatitis. Potential allergens were found among the emitted monoterpenes and their importance in airborne Compositae dermatitis is discussed....

  5. Medicinal compositae from Brazil

    International Nuclear Information System (INIS)

    Ferreira, Z.S.; Roque, N.F.; Gottlieb, O.R.; Oliveira, F.

    The family Compositae is one of the largest in the plant kingdom. Several species are used in popular medicin. Thus, the leaf extract of Calea pinnatifida Banks, known as aruca, is employed in the treatment of amoebiasis. A chemical study is carried out in order to discover the active principles of the species. (Author) [pt

  6. Patch testing with constituents of Compositae mixes

    DEFF Research Database (Denmark)

    Paulsen, Evy; Andersen, Klaus Ejner

    2012-01-01

    Background. The development of mixes containing Compositae plant extracts has improved the diagnosis of Compositae contact allergy, but none of them has fulfilled the criteria for an ideal European plant mix. Objective. To evaluate which constituents of two commercial Compositae mixes were most u...

  7. Cosmetics and herbal remedies with Compositae plant extracts - are they tolerated by Compositae-allergic patients?

    DEFF Research Database (Denmark)

    Paulsen, Evy; Christensen, Lars Porskjær; Andersen, Klaus Ejner

    2008-01-01

    BACKGROUND: Compositae-sensitive patients are routinely warned against topical use of Compositae-containing cosmetics and herbal remedies. However, the risk of elicitation of dermatitis in presensitized persons is unknown. OBJECTIVES: The main aim of this study was to assess the significance of d...

  8. Colophonium and Compositae mix as markers of fragrance allergy: cross-reactivity between fragrance terpenes, colophonium and compositae plant extracts

    DEFF Research Database (Denmark)

    Paulsen, Evy; Andersen, Klaus Ejner

    2005-01-01

    , colophonium and fragrance mix sensitization. The individual results indicated that simultaneously occurring positive reactions to essential oils, colophonium and Compositae were based on cross-reactivity rather than concomitant sensitization. Thus, all patients with positive reaction to the rare fragrance...... sensitizer beta-caryophyllene had positive colophonium reactions, and cross-reactivity between essential oils and Compositae was related to the Compositae plant extracts of the Compositae mix and not the pure sesquiterpene lactones of the standard series. The implication is that Compositae mix...... and colophonium may be markers of fragrance allergy, which is important to know when assessing the relevance of positive reactions to Compositae plant extracts and colophonium....

  9. Patch testing with constituents of Compositae mixes.

    Science.gov (United States)

    Paulsen, Evy; Andersen, Klaus E

    2012-05-01

    The development of mixes containing Compositae plant extracts has improved the diagnosis of Compositae contact allergy, but none of them has fulfilled the criteria for an ideal European plant mix. To evaluate which constituents of two commercial Compositae mixes were most useful as screening agents. These comprised 76 patients testing positive to Compositae mix 6% in petrolatum and 29 patients testing positive to Compositae mix 5% pet., all of whom were tested with constituents of the respective mixes. The majority of patients tested positive to parthenolide or parthenolide-containing extracts, followed by German chamomile, yarrow, and arnica. As German chamomile is a weak sensitizer, the results suggest cross-reactions or reactions to unknown allergens. No one was positive to Roman chamomile. Even though parthenolide seems to be a suitable supplement to the baseline series, the results emphasize that it is important to patch test with extracts of native or locally grown plants, not only because of the geographical variation, but also because of the potential unknown allergens contained in short ether preparations and the variability in the individual patient's exposure and cross-reaction patterns. © 2012 John Wiley & Sons A/S.

  10. Small area silicon diffused junction X-ray detectors

    Science.gov (United States)

    Walton, J. T.; Pehl, R. H.; Larsh, A. E.

    1982-01-01

    The low-temperature performance of silicon diffused junction detectors in the measurement of low energy X-rays is reported. The detectors have an area of 0.04 sq cm and a thickness of 100 microns. The spectral resolutions of these detectors were found to be in close agreement with expected values, indicating that the defects introduced by the high-temperature processing required in the device fabrication were not deleteriously affecting the detection of low-energy X-rays. Device performance over a temperature range of 77 K to 150 K is given. These detectors were designed to detect low-energy X-rays in the presence of minimum ionizing electrons. The successful application of silicon-diffused junction technology to X-ray detector fabrication may facilitate the development of other novel silicon X-ray detector designs.

  11. Small area silicon diffused junction x-ray detectors

    International Nuclear Information System (INIS)

    Walton, J.T.; Pehl, R.H.; Larsh, A.E.

    1981-10-01

    The low temperature performance of silicon diffused junction detectors in the measurement of low energy x-rays is reported. The detectors have an area of 0.04 cm 2 and a thickness of 100 μm. The spectral resolutions of these detectors were found to be in close agreement with expected values indicating that the defects introduced by the high temperature processing required in the device fabrication were not deleteriously affecting the detection of low energy x-rays. Device performance over a temperature range of 77 to 150 0 K is given. These detectors were designed to detect low energy x-rays in the presence of minimum ionizing electrons. The successful application of silicon diffused junction technology to x-ray detector fabrication may facilitate the development of other novel silicon x-ray detector designs

  12. AGROBACTERIUM-MEDIATED TRANSFORMATION OF COMPOSITAE PLANTS. I. CONSTRUCTION OF TRANSGENIC PLANTS AND «HAIRY» ROOTS WITH NEW PROPERTIES

    Directory of Open Access Journals (Sweden)

    N. A.Matvieieva

    2013-02-01

    Full Text Available The review explores some of the recent advances and the author's own researchs concerning biotechnological approaches for Agrobacterium tumefaciens- and A. rhizogenes-mediated transformation of Compositae family plants. This paper reviews the results of genetic transformation of Compositae plants, including edible (Cichorium intybus, Lactuca sativa, oil (Helianthus annuus, decorative (Gerbera hybrida, medical (Bidens pilosa, Artemisia annua, Artemisia vulgaris, Calendula officinalis, Withania somnifera etc. plant species. Some Compositae genetic engineering areas are considered including creation of plants, resistant to pests, diseases and herbicides, to the effect of abiotic stress factors as well as plants with altered phenotype. The article also presents the data on the development of biotechnology for Compositae plants Cynara cardunculus, Arnica montana, Cichorium intybus, Artemisia annua "hairy" roots construction.

  13. Towards molecular electronics with large-area molecular junctions

    NARCIS (Netherlands)

    Akkerman, HB; Blom, PWM; de Leeuw, DM; de Boer, B

    2006-01-01

    Electronic transport through single molecules has been studied extensively by academic(1-8) and industrial(9,10) research groups. Discrete tunnel junctions, or molecular diodes, have been reported using scanning probes(11,12), break junctions(13,14), metallic crossbars(6) and nanopores(8,15). For

  14. On the stability of large-area Al-p-Si junction

    International Nuclear Information System (INIS)

    Tsyganov, Yu.S.

    2006-01-01

    Design of silicon radiation detector made of 12 kΩ · cm p-silicon with both amine- and amine-free hardeners epoxy resin junction edge passivation is presented. Before producing large-area detectors for measurements of efficiency of evaporation residues collection at the focal plane of the Dubna Gas-Filled Recoil Separator (DGFRS), a set of small-area test detectors was produced. Stability of the Al-(p)Si junction has been studied for a long time. Estimate of a realistic lifetime for the mentioned type of Al-Si rectifying junction is done

  15. Microfungi on compositae in the Ruhr Basin.

    Science.gov (United States)

    Ale-Agha, N; Feige, G B; Dachowski, M

    2002-01-01

    Forty-three microfungi have been observed on thirty species of the Compositae occurring in several locations in the Ruhr Basin in North Rhine-Westphalia. Many fungi belong to the Ascomycetes (Erysiphales, Diaporthales, Dothideales, Leotiales and Pleosporales) and to the Deuteromycetes (Melanconiales, Moniliales and Sphaeropsidales). Other fungi wich were found in our investigation belong to the Basidiomycetes (Uredinales) and to the Oomycetes (Peronosporales). Some recorded microfungi have been discovered on new hosts in North Rhine-Westphalia and also in Germany for the first time. New for North Rhine-Westphalia are Ascochyta spec. Libert on Matricaria recutita L., Phoma exigua var. linicola (Naumov & Vassilevski) Maas on Tripleurospermum maritimum (L.) W. D. J. Koch, Phomopsis achillea (Sacc.) Höhn. on Achillea ageratum L., Diaporthe aff. arctii (Lasch) Nitschke on Solidago canadensis L. and on Achillea ageratum L., Lophiostoma caulium (Fr.) Ces. & De Not. on Anthemis tinctoria L. and Ophiobolus fructicum (Rob. ex Desm.) on Serratula tinctoria L. New for Germany are Ophiobolus cirsii (P. Karst.) Sacc. on Cichorium intybus L., Phomopsis cirsii Grove on Cirsium vulgare (Savi) Ten., Pleospora kansensis J. P. Ellis & M. B. Ellis and Pleospora phaeocomoides cf. var. infectoria on Centaurea jacea L.

  16. Contact sensitization from Compositae-containing herbal remedies and cosmetics.

    Science.gov (United States)

    Paulsen, Evy

    2002-10-01

    The Compositae (Asteraceae) family of plants is currently an important cause of allergic plant contact dermatitis in Europe. The family comprises some of the oldest and most valued medicinal plants, and the increasing popularity of herbal medicine and cosmetics may theoretically result in a growing number of Compositae sensitizations from these sources. According to the literature at least 15 species, including among others arnica (Arnica montana), German and Roman chamomile (Chamomilla recutita and Chamaemelum nobile), marigold (Calendula officinalis), Echinacea and elecampane (Inula helenium), have been suspected of sensitization or elicitation of Compositae dermatitis. Epidemiological data are available for 2 species only, arnica and German chamomile, the rest of the evidence being anecdotal. Based on this, sensitization seems to occur relatively frequently with a few species such as arnica and elecampane, and occurs rarely with the majority, especially the widely used German chamomile. Sesquiterpene lactones are the most important allergens, but there are a few cases of sensitization from a coumarin, a sesquiterpene alcohol and a thiophene. The risk of elicitation of dermatitis by using Compositae-containing products in Compositae-sensitive individuals is by-and-large unknown.

  17. Scalability of multi-junction organic solar cells for large area organic solar modules

    Science.gov (United States)

    Xiao, Xin; Lee, Kyusang; Forrest, Stephen R.

    2015-05-01

    We investigate the scalability of multi-junction organic photovoltaic cells (OPV) with device areas ranging from 1 mm2 to 1 cm2, as well as 25 cm2 active area solar modules. We find that the series resistance losses in 1 cm2 vs. 1 mm2 OPV cell efficiencies are significantly higher in single junction cells than tandem, triple, and four junction cells due to the lower operating voltage and higher current of the former. Using sub-electrodes to reduce series resistance, the power conversion efficiency (PCE) of multi-junction cells is almost independent of area from 1 mm2 to 1 cm2. Twenty-five, 1 cm2 multi-junction cell arrays are integrated in a module and connected in a series-parallel circuit configuration. A yield of 100% with a deviation of PCE from cell to cell of <10% is achieved. The module generates an output power of 162 ± 9 mW under simulated AM1.5G illumination at one sun intensity, corresponding to PCE = 6.5 ± 0.1%, slightly lower than PCE of discrete cells ranging from 6.7% to 7.2%.

  18. An 8-year experience with routine SL mix patch testing supplemented with Compositae mix in Denmark

    DEFF Research Database (Denmark)

    Paulsen, E; Andersen, Klaus Ejner; Hausen, B M

    2001-01-01

    Routine patch testing with sesquiterpene lactone (SL) mix, supplemented with Compositae mix (CM) and other Compositae extracts and allergens where appropriate, was evaluated over an 8-year period. 190 of 4386 patients tested (4.3%) were Compositae-sensitive, 143 females (mean age 51.5 years) and ...

  19. Period doubling and chaos in large area Josephson junctions induced by rf signals

    DEFF Research Database (Denmark)

    Olsen, O. H.; Samuelsen, Mogens Rugholm

    1985-01-01

    The influence of an applied rf signal on the emitted radiation from a large area Josephson junction is examined. A model of the system is presented in the framework of the one-dimensional sine-Gordon equation. The model linearizes for small and large values of the amplitude of the applied signal...

  20. in-vitro antimicrobial properties of aspilla africana (compositae).

    African Journals Online (AJOL)

    Dr Olaleye

    The in vitro anti-microbial activity of the petroleum ether, chloroform and methanol extracts of Aspilia africana. (Compositae) was studied. The bacterial used for the antimicrobial analysis consisted of 3 clinical strains of. Staphylococcus aureus, Bacillus subtilis, 2 clinical strains of Escherichia coli and Pseudomonas ...

  1. Preparation of large-area molecular junctions with metallic conducting Langmuir–Blodgett films

    Energy Technology Data Exchange (ETDEWEB)

    Mochizuki, Kengo [Division of Marine Technology, Tokyo University of Marine Science and Technology, 2-1-6 Etchujima Koto-ku, Tokyo 135-8533 (Japan); Ohnuki, Hitoshi, E-mail: ohnuki@kaiyodai.ac.jp [Division of Marine Technology, Tokyo University of Marine Science and Technology, 2-1-6 Etchujima Koto-ku, Tokyo 135-8533 (Japan); Shimizu, Daisuke [Division of Marine Technology, Tokyo University of Marine Science and Technology, 2-1-6 Etchujima Koto-ku, Tokyo 135-8533 (Japan); Imakubo, Tatsuro [Department of Materials and Technology, Nagaoka University of Technology, 1603-1 Kamitomioka, Nagaoka, Niigata 940-2188 (Japan); Tsuya, Daiju [National Institute for Materials Science,1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Izumi, Mitsuru [Division of Marine Technology, Tokyo University of Marine Science and Technology, 2-1-6 Etchujima Koto-ku, Tokyo 135-8533 (Japan)

    2014-03-03

    Metallic conducting Langmuir–Blodgett (LB) films were used as soft electrodes to fabricate molecular junctions with self-assembled monolayers (SAMs) of alkanethiols (CH{sub 3}(CH{sub 2}){sub n−1}SH) on an Au surface. Alkanethiols can form highly ordered, stable dielectric SAMs on metal surfaces over large areas. However, it is difficult to establish electrical contacts on such SAMs, which has limited their application. In this work, we used metallic conducting LB films composed of bis(ethylenedioxy)tetrathiafulvalene and stearic acid as a soft electrode onto alkanethiol SAMs (C{sub n}-SAM, n = 12, 14, 16, 18) to prepare Au/SAM/metal junctions of relatively large size (∼ 15.6 × 10{sup 3} μm{sup 2}). The current density–voltage (J–V) characteristics across the junctions exhibited rectifying behavior with a ratio R of ∼ 5 (R = |J(V)|/|J(− V)| at ± 1 V). The lower transfer rate corresponding to the electron transport from Au to the LB films exhibited nonlinear J–V characteristics, while the higher transfer rate of electrons from the LB film to Au showed linear J–V characteristics. Kelvin probe force microscopy revealed that the work function of the metallic LB films was smaller than that of Au. The observed rectification behavior is probably caused by different electron transport mechanisms between the two current directions. - Highlights: • Metallic Langmuir–Blodgett (LB) films were used as soft electrodes. • Molecular junctions of metal–alkanethiol–LB films were fabricated. • The current–voltage curve across the junctions exhibited rectifying behavior. • This is the first observation for alkanethiol monolayer junctions. • The work function difference between the electrodes induces the rectification.

  2. Fabrication and dc characteristics of small-area tantalum and niobium superconducting tunnel junctions

    International Nuclear Information System (INIS)

    Face, D.W.; Prober, D.E.

    1987-01-01

    We discuss the fabrication and dc electrical characteristics of small-area (1--6 μm 2 ) superconducting tunnel junctions with Ta or Nb base electrodes and Pb or Pb/sub 0.9/Bi/sub 0.1/ counterelectrodes. These junctions have very small subgap leakage currents, a ''sharp'' current rise at the sum-gap voltage, and show strong quantum effects when used as microwave mixers. The use of a low-energy (--150 eV) ion cleaning process and a novel step-defined fabrication process that eliminates photoresist processing after base electrode deposition are discussed. Tunnel barriers formed by dc glow discharge oxidation were the most successful. Tunnel barrier formation by thermal oxidation and ion-beam oxidation is also discussed. An oxidized Ta overlayer (--7 nm thick) was found to improve the characteristics of Nb-based junctions. The electrical characteristics of junctions with different electrode and barrier materials are presented and discussed in terms of the physical mechanisms that lead to excess subgap current and to a width of the current rise at the sum-gap voltage

  3. Co-activation-based parcellation of the lateral prefrontal cortex delineates the inferior frontal junction area

    OpenAIRE

    Muhle-Karbe, Paul Simon; Derrfuss, Jan; Lynn, Maggie; Neubert, Franz Xaver; Fox, Peter; Brass, Marcel; Eickhoff, Simon

    2016-01-01

    The inferior frontal junction (IFJ) area, a small region in the posterior lateral prefrontal cortex (LPFC), has received increasing interest in recent years due to its central involvement in the control of action, attention, and memory. Yet, both its function and anatomy remain controversial. Here, we employed a meta-analytic parcellation of the left LPFC to show that the IFJ can be isolated based on its specific functional connections. A seed region, oriented along the left inferior frontal ...

  4. Sunflower seeds as eliciting agents of Compositae dermatitis

    DEFF Research Database (Denmark)

    Paulsen, Evy; El-Houri, Rime B; Andersen, Klaus Ejner

    2015-01-01

    BACKGROUND: Sunflowers may cause dermatitis because of allergenic sesquiterpene lactones (SLs). Contact sensitization to sunflower seeds has also been reported, but the allergens are unknown. OBJECTIVES: To analyse sunflower seeds for the presence of SLs and to assess the prevalence of sunflower...... sensitization in Compositae-allergic individuals. PATIENTS/MATERIALS/METHODS: Sunflower-sensitive patients were identified by aimed patch testing. A dichloromethane extract of whole sunflower seeds was analysed by liquid chromatography-mass spectrometry and high-performance liquid chromatography. RESULTS......: The prevalence of sensitivity to sunflower in Compositae-allergic individuals was 56%. A solvent wash of whole sunflower seeds yielded an extract containing SLs, the principal component tentatively being identified as argophyllin A or B, other SLs being present in minute amounts. CONCLUSIONS: The concentration...

  5. Occupational dermatitis in Danish gardeners and greenhouse workers (III). Compositae-related symptoms.

    Science.gov (United States)

    Paulsen, E; Søgaard, J; Andersen, K E

    1998-03-01

    The clinical part of the study aimed at describing epidemiological and diagnostic aspects of occupational Compositae dermatitis. Patch testing with the sesquiterpene lactone (SL) and Compositae mixes, feverfew extract and supplementary allergens in 250 selected gardeners showed Compositae allergy in 25, 17 females and 8 males. 24 were possibly occupationally sensitized. The mean age was lower and the preponderance of women higher compared to classical Compositae dermatitis, and the distribution and course of the dermatitis most often did not differ from other occupational plant dermatoses. The Compositae mix detected 2x as many as the SL mix, and the overall detection rate with both was 76%, making aimed patch testing necessary. Chrysanthemum (Dendranthema), marguerite daisy (Argyranthemum frutescens) and lettuce (Lactuca sativa) were frequent sensitizers. Occupational type I allergy to Compositae comprised sensitization to Gerbera, chrysanthemum, lettuce, Senecio cruentus and Aster. Among 1657 respondents in the questionnaire part of the study, 824 had worked with Compositae, and 160 (19%) reported occupational Compositae-related symptoms of skin and mucous membranes. Possible risk factors for the development of these were assessed in a stepwise logistic regression model and a history of childhood eczema, hay fever and duration of exposure were significantly associated with Compositae-related irritant and allergic symptoms in both sexes.

  6. Large-Area, Multi-Junction, Epitaxial Lift-Off Solar Cells with Backside Contacts, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — In this Phase II program we propose to develop a manufacturable production process to introduce backside contacts to MicroLink Devices? large-area, multi-junction...

  7. Large-Area, Multi-Junction, Epitaxial Lift-Off Solar Cells with Backside Contacts, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In this Phase I program we propose to develop an innovative fabrication process to introduce backside contacts to MicroLink Devices' large-area, multi-junction...

  8. Desmosomal Molecules In and Out of Adhering Junctions: Normal and Diseased States of Epidermal, Cardiac and Mesenchymally Derived Cells

    Directory of Open Access Journals (Sweden)

    Sebastian Pieperhoff

    2010-01-01

    Full Text Available Current cell biology textbooks mention only two kinds of cell-to-cell adhering junctions coated with the cytoplasmic plaques: the desmosomes (maculae adhaerentes, anchoring intermediate-sized filaments (IFs, and the actin microfilament-anchoring adherens junctions (AJs, including both punctate (puncta adhaerentia and elongate (fasciae adhaerentes structures. In addition, however, a series of other junction types has been identified and characterized which contain desmosomal molecules but do not fit the definition of desmosomes. Of these special cell-cell junctions containing desmosomal glycoproteins or proteins we review the composite junctions (areae compositae connecting the cardiomyocytes of mature mammalian hearts and their importance in relation to human arrhythmogenic cardiomyopathies. We also emphasize the various plakophilin-2-positive plaques in AJs (coniunctiones adhaerentes connecting proliferatively active mesenchymally-derived cells, including interstitial cells of the heart and several soft tissue tumor cell types. Moreover, desmoplakin has also been recognized as a constituent of the plaques of the complexus adhaerentes connecting certain lymphatic endothelial cells. Finally, we emphasize the occurrence of the desmosomal transmembrane glycoprotein, desmoglein Dsg2, out of the context of any junction as dispersed cell surface molecules in certain types of melanoma cells and melanocytes. This broadening of our knowledge on the diversity of AJ structures indicates that it may still be too premature to close the textbook chapters on cell-cell junctions.

  9. PCB usage at the Grand Junction Area Office Facility. Final report

    International Nuclear Information System (INIS)

    Miller, M.E.; Donivan, S.

    1982-06-01

    The development, implementation, and results of the polychlorinated biphenyl (PCB) identification project at the Grand Junction Area Office (GJAO) are summarized. Methodology for the PCB analysis is described, and results are tabulated. Of the 51 transformers and disconnects in use at GJAO, 15 unites were determined to be PCB-contaminated or filled with PCBs. This number falls within EPA's estimate of 25 to 40 percent of all transformers in use being at least contaminated. Approximately 324 gallons of PCBs and 515 gallons of PCB-contaminated fluids are being used currently. No contaminated transformers or disconnects are in a position to contaminate food or feed products at the facility

  10. Preparation of small-area Josephson junction using the scratched edge of a Pb/In layer

    International Nuclear Information System (INIS)

    Okuyama, K.; Gundlach, K.H.; Hartfuss, H.J.

    1980-01-01

    Superconductor-insulator-superconductor (SIS) Josephson junctions with areas less than 1 μm 2 were formed at the scratched edge of the Pb/In electrode. The scratch was made with a razor blade. Notwithstanding the simple technique used for scratching, the yield to get good junction is relatively high. The I-V characteristic with and without 70-GHz radiation is shown

  11. Compositae dermatitis in a Danish dermatology department in one year (I)

    DEFF Research Database (Denmark)

    Paulsen, Evy; Andersen, Klaus Ejner; Hausen, B M

    1993-01-01

    To investigate the frequency of Compositae sensitivity, the recently-developed sesquiterpene lactone mix (SL mix) was included in the standard patch test series. Patients with positive reactions to this or patients suspected of having a Compositae allergy were supplementarily tested with a Compos...

  12. Compositae dermatitis in a Danish dermatology department in 1 year (II)

    DEFF Research Database (Denmark)

    Paulsen, Evy; Andersen, Klaus Ejner

    1993-01-01

    During our first year of routine testing with Compositae allergens and extracts, contact allergy to Compositae was frequently found in eczema patients (4.5%), especially in middle-aged or elderly persons. Based on clinical patterns, patch test reactions and the long-term course of the disease, 4 ...

  13. Dose distribution at junctional area abutting X-ray and electron fields

    International Nuclear Information System (INIS)

    Yang, Kwang Mo

    2004-01-01

    For the head and neck radiotherapy, abutting photon field with electron field is frequently used for the irradiation of posterior neck when tolerable dose on spinal cord has been reached. Using 6 MV X-ray and 9 MeV electron beams of Clinac1800(Varian, USA) linear accelerator, we performed film dosimetry by the X-OMAT V film of Kodak in solid water phantom according to depths(0 cm, 1.5 cm, 3 cm, 5 cm). 6 MV X-ray and 9 MeV electron(1 Gy) were exposes to 8 cm depth and surface(SSD 100 cm) of phantom. The dose distribution to the junction line between photon(10 x 10 cm field with block) and electron(15 cm x 15 cm field with block) fields was also measured according to depths(0 cm, 0.5 1.5 cm, 3 cm, 5 cm). At the junction line between photon and electron fields, the hot spot was developed on the side of the photon field and a cold spot was developed on that of the electron field. The hot spot in the photon side was developed at depth 1.5 cm with 7 mm width. The maximum dose of hot spot was increased to 6% of reference doses in the photon field. The cold spot in the electron side was developed at all measured depths(0.5 cm-3 cm) with 1-12.5 mm widths. The decreased dose in the cold spot was 4.5-30% of reference dose in the electron field. When we make use of abutting photon field with electron field for the treatment of head and neck cancer we should consider the hot and cold dose area in the junction of photon and electron field according to location of tumor.

  14. Tuning the thickness of electrochemically grafted layers in large area molecular junctions

    Energy Technology Data Exchange (ETDEWEB)

    Fluteau, T.; Bessis, C.; Barraud, C., E-mail: clement.barraud@univ-paris-diderot.fr; Della Rocca, M. L.; Lafarge, P. [Université Paris Diderot, Sorbonne Paris Cité, MPQ, UMR 7162, CNRS, 75205 Paris Cedex 13 (France); Martin, P.; Lacroix, J.-C. [Université Paris Diderot, Sorbonne Paris Cité, ITODYS, UMR 7086, CNRS, 15 rue J.-A. de Baïf, 75205 Paris Cedex 13 (France)

    2014-09-21

    We have investigated the thickness, the surface roughness, and the transport properties of oligo(1-(2-bisthienyl)benzene) (BTB) thin films grafted on evaporated Au electrodes, thanks to a diazonium-based electro-reduction process. The thickness of the organic film is tuned by varying the number of electrochemical cycles during the growth process. Atomic force microscopy measurements reveal the evolution of the thickness in the range of 2–27 nm. Its variation displays a linear dependence with the number of cycles followed by a saturation attributed to the insulating behavior of the organic films. Both ultrathin (2 nm) and thin (12 and 27 nm) large area BTB-based junctions have then been fabricated using standard CMOS processes and finally electrically characterized. The electronic responses are fully consistent with a tunneling barrier in case of ultrathin BTB film whereas a pronounced rectifying behavior is reported for thicker molecular films.

  15. Sensitization patterns in Compositae-allergic patients with current or past atopic dermatitis

    DEFF Research Database (Denmark)

    Paulsen, Evy; Andersen, Klaus Ejner

    2013-01-01

    Background. An association between Compositae sensitization and atopic dermatitis has been suggested on the basis of case reports and clinical studies. Objectives. To describe the characteristics of sensitization in Compositae-allergic patients with current and/or past atopic dermatitis. Patients/materials......-atopics, except that dandelion was an important allergen in children. Cobalt allergy was the most frequent other contact allergy, occurring in 37%. Conclusions. Persons with current or past atopic dermatitis may become sensitized to Compositae at any age, both occupationally and non-occupationally. They should...

  16. Do monoterpenes released from feverfew (Tanacetum parthenium) plants cause airborne Compositae dermatitis?

    DEFF Research Database (Denmark)

    Paulsen, E.; Christensen, Lars Porskjær; Andersen, K.E.

    2002-01-01

    The Compositae plant feverfew (Tanacetum parthenium) is an important sensitizer in Europe and has been suspected of causing airborne Compositae dermatitis. A previous investigation of substances emitted from feverfew plants detected no sesquiterpene lactones, however, but mainly monoterpenes...... airborne dermatitis, mimicking photosensitivity, and the disappearance of symptoms upon removal of feverfew plants suggest monoterpenes as a possible contributing factor. Similar associations between doubtful positive monoterpene reactions and clinical patterns, fragrance/colophonium allergy and relevance...

  17. The origin of the bifurcating style in Asteraceae (Compositae).

    Science.gov (United States)

    Katinas, Liliana; Hernández, Marcelo P; Arambarri, Ana M; Funk, Vicki A

    2016-05-01

    The plant family Asteraceae (Compositae) exhibits remarkable morphological variation in the styles of its members. Lack of studies on the styles of the sister families to Asteraceae, Goodeniaceae and Calyceraceae, obscures our understanding of the origin and evolution of this reproductive feature in these groups. The aim of this work was to perform a comparative study of style morphology and to discuss the relevance of important features in the evolution of Asteraceae and its sister families. The histochemistry, venation and general morphology of the styles of members of Goodeniaceae, Calyceraceae and early branching lineages of Asteraceae were analysed and put in a phylogenetic framework to discuss the relevance of style features in the evolution of these families. The location of lipophilic substances allowed differentiation of receptive from non-receptive style papillae, and the style venation in Goodeniaceae and Calyceraceae proved to be distinctive. There were several stages of style evolution from Goodeniaceae to Asteraceae involving connation and elongation of veins, development of bilobation from an initially cup-shaped style, and a redistribution of the receptive and non-receptive papillae. These developments resulted in bifurcation in the styles of Asteraceae, with each branch face having a different function, and it is suggested here as a mechanism that promoted outcrossing, which in turn led to the great diversification in the family. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Defining the value of injection current and effective electrical contact area for EGaIn-based molecular tunneling junctions.

    Science.gov (United States)

    Simeone, Felice C; Yoon, Hyo Jae; Thuo, Martin M; Barber, Jabulani R; Smith, Barbara; Whitesides, George M

    2013-12-04

    Analysis of rates of tunneling across self-assembled monolayers (SAMs) of n-alkanethiolates SCn (with n = number of carbon atoms) incorporated in junctions having structure Ag(TS)-SAM//Ga2O3/EGaIn leads to a value for the injection tunnel current density J0 (i.e., the current flowing through an ideal junction with n = 0) of 10(3.6±0.3) A·cm(-2) (V = +0.5 V). This estimation of J0 does not involve an extrapolation in length, because it was possible to measure current densities across SAMs over the range of lengths n = 1-18. This value of J0 is estimated under the assumption that values of the geometrical contact area equal the values of the effective electrical contact area. Detailed experimental analysis, however, indicates that the roughness of the Ga2O3 layer, and that of the Ag(TS)-SAM, determine values of the effective electrical contact area that are ~10(-4) the corresponding values of the geometrical contact area. Conversion of the values of geometrical contact area into the corresponding values of effective electrical contact area results in J0(+0.5 V) = 10(7.6±0.8) A·cm(-2), which is compatible with values reported for junctions using top-electrodes of evaporated Au, and graphene, and also comparable with values of J0 estimated from tunneling through single molecules. For these EGaIn-based junctions, the value of the tunneling decay factor β (β = 0.75 ± 0.02 Å(-1); β = 0.92 ± 0.02 nC(-1)) falls within the consensus range across different types of junctions (β = 0.73-0.89 Å(-1); β = 0.9-1.1 nC(-1)). A comparison of the characteristics of conical Ga2O3/EGaIn tips with the characteristics of other top-electrodes suggests that the EGaIn-based electrodes provide a particularly attractive technology for physical-organic studies of charge transport across SAMs.

  19. Most Compositae (Asteraceae) are descendants of a paleohexaploid and all share a paleotetraploid ancestor with the Calyceraceae.

    Science.gov (United States)

    Barker, Michael S; Li, Zheng; Kidder, Thomas I; Reardon, Chris R; Lai, Zhao; Oliveira, Luiz O; Scascitelli, Moira; Rieseberg, Loren H

    2016-07-01

    Like many other flowering plants, members of the Compositae (Asteraceae) have a polyploid ancestry. Previous analyses found evidence for an ancient duplication or possibly triplication in the early evolutionary history of the family. We sought to better place this paleopolyploidy in the phylogeny and assess its nature. We sequenced new transcriptomes for Barnadesia, the lineage sister to all other Compositae, and four representatives of closely related families. Using a recently developed algorithm, MAPS, we analyzed nuclear gene family phylogenies for evidence of paleopolyploidy. We found that the previously recognized Compositae paleopolyploidy is also in the ancestry of the Calyceraceae. Our phylogenomic analyses uncovered evidence for a successive second round of genome duplication among all sampled Compositae except Barnadesia. Our analyses of new samples with new tools provide a revised view of paleopolyploidy in the Compositae. Together with results from a high density Lactuca linkage map, our results suggest that the Compositae and Calyceraceae have a common paleotetraploid ancestor and that most Compositae are descendants of a paleohexaploid. Although paleohexaploids have been previously identified, this is the first example where the paleotetraploid and paleohexaploid lineages have survived over tens of millions of years. The complex polyploidy in the ancestry of the Compositae and Calyceraceae represents a unique opportunity to study the long-term evolutionary fates and consequences of different ploidal levels. © 2016 Botanical Society of America.

  20. Final report of the decontamination and decommissioning of the exterior land areas at the Grand Junction Projects Office facility

    Energy Technology Data Exchange (ETDEWEB)

    Widdop, M.R.

    1995-09-01

    The US Department of Energy (DOE) Grand Junction Projects Office (GJPO) facility occupies approximately 56.4 acres (22.8 hectares) along the Gunnison River near Grand Junction, Colorado. The site was contaminated with uranium ore and mill tailings during uranium-refining activities conducted by the Manhattan Engineer District and during pilot-milling experiments conducted for the US Atomic Energy Commission`s (AEC`s) domestic uranium procurement program. The GJPO facility was the collection and assay point for AEC uranium and vanadium oxide purchases until the early 1970s. The DOE Decontamination and Decommissioning Program sponsored the Grand Junction Projects Office Remedial Action Project (GJPORAP) to remediate the facility lands, site improvements, and the underlying aquifer. The site contractor, Rust Geotech, was the Remedial Action Contractor for GJPORAP. The exterior land areas of the facility assessed as contaminated have been remediated in accordance with identified standards and can be released for unrestricted use. Restoration of the aquifer will be accomplished through the natural flushing action of the aquifer during the next 50 to 80 years. The remediation of the DOE-GJPO facility buildings is ongoing and will be described in a separate report.

  1. GC-MS Analysis of the Volatile Constituents in the Leaves of 14 Compositae Plants

    Directory of Open Access Journals (Sweden)

    Yiguang Wang

    2018-01-01

    Full Text Available The green organs, especially the leaves, of many Compositae plants possess characteristic aromas. To exploit the utility value of these germplasm resources, the constituents, mainly volatile compounds, in the leaves of 14 scented plant materials were qualitatively and quantitatively compared via gas chromatography-mass spectrometry (GC-MS. A total of 213 constituents were detected and tentatively identified in the leaf extracts, and terpenoids (especially monoterpene and sesquiterpene derivatives, accounting for 40.45–90.38% of the total compounds, were the main components. The quantitative results revealed diverse concentrations and compositions of the chemical constituents between species. Principal component analysis (PCA showed that different groups of these Compositae plants were characterized by main components of α-thujone, germacrene D, eucalyptol, β-caryophyllene, and camphor, for example. On the other hand, cluster memberships corresponding to the molecular phylogenetic framework, were found by hierarchical cluster analysis (HCA based on the terpenoid composition of the tested species. These results provide a phytochemical foundation for the use of these scented Compositae plants, and for the further study of the chemotaxonomy and differential metabolism of Compositae species.

  2. Aerial radiological survey of the area surrounding the UNC Recovery Systems Facility, Wood River Junction, Rhode Island

    International Nuclear Information System (INIS)

    Bluitt, C.M.

    1981-05-01

    An aerial radiological survey to measure terrestrial gamma radiation was carried out over the United Nuclear Corporation (UNC) Recovery Systems Facility located near Wood River Junction, Rhode Island. At the time of the survey (August 1979) materials were being processed at the facility. Gamma ray data were collected over a 3.28 km 2 area centered on the facility by flying north-south lines spaced 60 m apart. Processed data indicated that detected radioisotopes and their associated gamma ray exposure rates were consistent with those expected from normal background emitters, except directly over the UNC Facility. Average exposure rates 1 m above the ground, as calculated from the aerial data, are presented in the form of an isopleth map. No ground sample data were taken at the time of the aerial survey

  3. Medium area, flexible single and tandem junction solar cells based on roll coated semi-random copolymers

    DEFF Research Database (Denmark)

    Andersen, Thomas Rieks; Dam, Henrik Friis; Burkhart, Beate

    2014-01-01

    laboratory roll-coater using only slot-die coating and flexographic printing under ambient conditions on a flexible ITO-free substrate. In order to overcome a low JSC and FF obtained for single junction devices, devices were also prepared in a tandem geometry making it possible to employ thinner junction...... films. Power conversion efficiencies of up to 1.36% and 1.31% were achieved for the tandem and single junction geometries, respectively....

  4. Josephson junction arrays

    International Nuclear Information System (INIS)

    Bindslev Hansen, J.; Lindelof, P.E.

    1985-01-01

    In this review we intend to cover recent work involving arrays of Josephson junctions. The work on such arrays falls naturally into three main areas of interest: 1. Technical applications of Josephson junction arrays for high-frequency devices. 2. Experimental studies of 2-D model systems (Kosterlitz-Thouless phase transition, commensurate-incommensurate transition in frustrated (flux) lattices). 3. Investigations of phenomena associated with non-equilibrium superconductivity in and around Josephson junctions (with high current density). (orig./BUD)

  5. Intoxicação espontânea por Baccharis coridifolia (Compositae em ovinos Spontaneous Baccharis coridifolia (Compositae poisoning in sheep

    Directory of Open Access Journals (Sweden)

    Daniela B. Rozza

    2006-03-01

    Full Text Available Descreve-se uma mortalidade de ovinos associada à intoxicação espontânea por Baccharis coridifolia ("mio-mio". A intoxicação ocorreu no município de Caxias do Sul, RS, em novembro de 2004. De um lote de 212 ovinos, provenientes de pastagens livres de B. coridifolia, no município de Jaguarão, RS, morreram 35 ovinos em até 5 dias após serem liberadas para o pasto onde mio-mio era encontrado em abundância, apesar de terem sido removidos deste pasto 1 dia e meio após sua introdução. Ovinos que anteriormente estavam na propriedade não foram afetados. O quadro clínico iniciou-se 8 horas após a introdução dos animais na nova pastagem e incluiu anorexia, depressão, retração abdominal ou leve timpanismo, incoordenação de membros posteriores, fezes pastosas, corrimento nasal catarral, decúbito lateral com movimentos de pedalagem, coma e morte com evolução clínica entre 5 e 48 horas. Os principais achados de necropsia foram no trato digestivo com edema de serosa e da parede dos pré-estômagos principalmente na região retículo-ruminal e do abomaso, avermelhamento e desprendimento da mucosa ruminal e do retículo e intensa hemorragia na submucosa. No exame histológico havia degeneração e necrose do epitélio do pré-estômago, com infiltrado polimorfonuclear, congestão, hemorragia e edema, e necrose do tecido linfóide de linfonodos, baço e trato digestivo.An outbreak of Baccharis coridifolia (Compositae poisoning in sheep is reported, which occurred in November 2004 in the county of Caxias do Sul, Rio Grande do Sul (RS, southern Brazil. From a herd of 212 sheep, coming from a Baccharis coridifolia free area, in the county of Jaguarão, RS, 35 sheep died until 5 days after the arrival in the new area where the plant was found with abundance. The clinical signs began 8 hours after introduction of the animals into the new pasture and included apathy, anorexia, abdominal retraction or mild distension, weakness of hind limbs

  6. Large area, low capacitance, GaAs nanowire photodetector with a transparent Schottky collecting junction

    Energy Technology Data Exchange (ETDEWEB)

    Seyedi, M. A., E-mail: seyedi@usc.edu; Yao, M.; O' Brien, J.; Dapkus, P. D. [Center for Energy Nanoscience, University of Southern California, Los Angeles, California 90089 (United States); Wang, S. Y. [Center for Energy Nanoscience, University of Southern California, Los Angeles, California 90089 (United States); Nanostructured Energy Conversion Technology and Research (NECTAR), Advanced Studies Laboratories, University of California, Santa Cruz, California 95064, USA and NASA Ames Research Center, Moffett Field, California 94035 (United States)

    2013-12-16

    We present experimental results on a GaAs/Indium-Tin-Oxide Schottky-like heterojunction photodetector based on a nanowire device geometry. By distributing the active detecting area over an array of nanowires, it is possible to achieve large area detection with low capacitance. Devices with bare GaAs and passivated AlGaAs/GaAs nanowires are fabricated to compare the responsivity with and without surface passivation. We are able to achieve responsivity of >0.5A/W and Signal-Noise-Ratio in excess of 7 dB for 2 V applied reverse bias with passivated nanowire devices. Capacitance-voltage measurement yields <5 nF/cm{sup 2}, which shows a strong possibility for high-speed applications with a broad area device.

  7. Large area, low capacitance, GaAs nanowire photodetector with a transparent Schottky collecting junction

    International Nuclear Information System (INIS)

    Seyedi, M. A.; Yao, M.; O'Brien, J.; Dapkus, P. D.; Wang, S. Y.

    2013-01-01

    We present experimental results on a GaAs/Indium-Tin-Oxide Schottky-like heterojunction photodetector based on a nanowire device geometry. By distributing the active detecting area over an array of nanowires, it is possible to achieve large area detection with low capacitance. Devices with bare GaAs and passivated AlGaAs/GaAs nanowires are fabricated to compare the responsivity with and without surface passivation. We are able to achieve responsivity of >0.5A/W and Signal-Noise-Ratio in excess of 7 dB for 2 V applied reverse bias with passivated nanowire devices. Capacitance-voltage measurement yields 2 , which shows a strong possibility for high-speed applications with a broad area device

  8. De novo transcriptome assembly and the putative biosynthetic pathway of steroidal sapogenins of Dioscorea composita.

    Directory of Open Access Journals (Sweden)

    Xia Wang

    Full Text Available The plant Dioscorea composita has important applications in the medical and energy industries, and can be used for the extraction of steroidal sapogenins (important raw materials for the synthesis of steroidal drugs and bioethanol production. However, little is known at the genetic level about how sapogenins are biosynthesized in this plant. Using Illumina deep sequencing, 62,341 unigenes were obtained by assembling its transcriptome, and 27,720 unigenes were annotated. Of these, 8,022 unigenes were mapped to 243 specific pathways, and 531 unigenes were identified to be involved in 24 secondary metabolic pathways. 35 enzymes, which were encoded by 79 unigenes, were related to the biosynthesis of steroidal sapogenins in this transcriptome database, covering almost all the nodes in the steroidal pathway. The results of real-time PCR experiments on ten related transcripts (HMGR, MK, SQLE, FPPS, DXS, CAS, HMED, CYP51, DHCR7, and DHCR24 indicated that sapogenins were mainly biosynthesized by the mevalonate pathway. The expression of these ten transcripts in the tuber and leaves was found to be much higher than in the stem. Also, expression in the shoots was low. The nucleotide and protein sequences and conserved domains of four related genes (HMGR, CAS, SQS, and SMT1 were highly conserved between D. composita and D. zingiberensis; but expression of these four genes is greater in D. composita. However, there is no expression of these key enzymes in potato and no steroidal sapogenins are synthesized.

  9. Graphene-Molybdenum Disulfide-Graphene Tunneling Junctions with Large-Area Synthesized Materials.

    Science.gov (United States)

    Joiner, Corey A; Campbell, Philip M; Tarasov, Alexey A; Beatty, Brian R; Perini, Chris J; Tsai, Meng-Yen; Ready, William J; Vogel, Eric M

    2016-04-06

    Tunneling devices based on vertical heterostructures of graphene and other 2D materials can overcome the low on-off ratios typically observed in planar graphene field-effect transistors. This study addresses the impact of processing conditions on two-dimensional materials in a fully integrated heterostructure device fabrication process. In this paper, graphene-molybdenum disulfide-graphene tunneling heterostructures were fabricated using only large-area synthesized materials, unlike previous studies that used small exfoliated flakes. The MoS2 tunneling barrier is either synthesized on a sacrificial substrate and transferred to the bottom-layer graphene or synthesized directly on CVD graphene. The presence of graphene was shown to have no impact on the quality of the grown MoS2. The thickness uniformity of MoS2 grown on graphene and SiO2 was found to be 1.8 ± 0.22 nm. XPS and Raman spectroscopy are used to show how the MoS2 synthesis process introduces defects into the graphene structure by incorporating sulfur into the graphene. The incorporation of sulfur was shown to be greatly reduced in the absence of molybdenum suggesting molybdenum acts as a catalyst for sulfur incorporation. Tunneling simulations based on the Bardeen transfer Hamiltonian were performed and compared to the experimental tunneling results. The simulations show the use of MoS2 as a tunneling barrier suppresses contributions to the tunneling current from the conduction band. This is a result of the observed reduction of electron conduction within the graphene sheets.

  10. Genomics of Compositae crops: reference transcriptome assemblies and evidence of hybridization with wild relatives.

    Science.gov (United States)

    Hodgins, Kathryn A; Lai, Zhao; Oliveira, Luiz O; Still, David W; Scascitelli, Moira; Barker, Michael S; Kane, Nolan C; Dempewolf, Hannes; Kozik, Alex; Kesseli, Richard V; Burke, John M; Michelmore, Richard W; Rieseberg, Loren H

    2014-01-01

    Although the Compositae harbours only two major food crops, sunflower and lettuce, many other species in this family are utilized by humans and have experienced various levels of domestication. Here, we have used next-generation sequencing technology to develop 15 reference transcriptome assemblies for Compositae crops or their wild relatives. These data allow us to gain insight into the evolutionary and genomic consequences of plant domestication. Specifically, we performed Illumina sequencing of Cichorium endivia, Cichorium intybus, Echinacea angustifolia, Iva annua, Helianthus tuberosus, Dahlia hybrida, Leontodon taraxacoides and Glebionis segetum, as well 454 sequencing of Guizotia scabra, Stevia rebaudiana, Parthenium argentatum and Smallanthus sonchifolius. Illumina reads were assembled using Trinity, and 454 reads were assembled using MIRA and CAP3. We evaluated the coverage of the transcriptomes using BLASTX analysis of a set of ultra-conserved orthologs (UCOs) and recovered most of these genes (88-98%). We found a correlation between contig length and read length for the 454 assemblies, and greater contig lengths for the 454 compared with the Illumina assemblies. This suggests that longer reads can aid in the assembly of more complete transcripts. Finally, we compared the divergence of orthologs at synonymous sites (Ks) between Compositae crops and their wild relatives and found greater divergence when the progenitors were self-incompatible. We also found greater divergence between pairs of taxa that had some evidence of postzygotic isolation. For several more distantly related congeners, such as chicory and endive, we identified a signature of introgression in the distribution of Ks values. © 2013 John Wiley & Sons Ltd.

  11. INSECTICIDAL ACTIVITY OF AERIAL PARTS OF SYNEDRELLA NODIFLORA GAERTN (COMPOSITAE ON SPODOPTERA LITURA (FAB.

    Directory of Open Access Journals (Sweden)

    MARTIN RATHI J.

    2006-05-01

    Full Text Available Spodoptera litura (Fabricius is the most serious pest of many cultivated and non-cultivated crops and it developed resistance against many synthetic pesticides. The impact of a Compositae annual weed, Synedrella nodifl ora Gaertn. solvent extracts on the fourth instar larvae of S. litura has been evaluated by leaf dip method. The LD50 results revealed that methanol extract is the most toxic to the pest followed by benzene and chloroform, petroleum ether (400 – 600 C and water. Qualitative phytochemical analysis has also been performed.

  12. INSECTICIDAL ACTIVITY OF AERIAL PARTS OF SYNEDRELLA NODIFLORA GAERTN (COMPOSITAE ON SPODOPTERA LITURA (FAB.

    Directory of Open Access Journals (Sweden)

    J MARTIN RATHI

    2006-12-01

    Full Text Available Spodoptera litura (Fabricius is the most serious pest of many cultivated and non-cultivated crops and it developed resistance against many synthetic pesticides. The impact of a Compositae annual weed, Synedrella nodifl ora Gaertn. solvent extracts on the fourth instar larvae of S. litura has been evaluated by leaf dip method. The LD50 results revealed that methanol extract is the most toxic to the pest followed by benzene and chloroform, petroleum ether (400 – 600 C and water. Qualitative phytochemical analysis has also been performed.

  13. Floral flavonoids and ultraviolet patterns in Viguiera (Compositae)

    International Nuclear Information System (INIS)

    Rieseberg, L.H.; Schilling, E.E.

    1985-01-01

    Variation occurs among species of Viguiera series Viguiera for ultraviolet (UV) absorption/reflection patterns of ligules. Floral flavonoids that cause UV absorption occur in epidermal papillae. Flavonoids are further localized to the proximal portion of the ligule in the seven taxa that have only proximal UV absorption. Floral flavonoids involved in UV absorption consist of flavone, flavonol, and anthochlor (chalcone/aurone) glycosides. Quercetin 3-methyl ether glycosides characterize the ligules of 10 taxa occurring in Baja California, Mexico, and nearby areas, and these taxa appear to form one taxonomic group. The anthochlor pair, marein/maritimein, characterizes V. dentata, and the lack of ligule flavonoids distinguishes V. potosina from the remaining taxa. The presence of the anthochlor pair, marein/maritimein, only in V. dentata and the lack of ligule flavonoids in V. potosina concur with other data to indicate that these species are not correctly placed with each other or with the other species currently included in series Viguiera. (author)

  14. Ultra-low switching energy and scaling in electric-field-controlled nanoscale magnetic tunnel junctions with high resistance-area product

    Energy Technology Data Exchange (ETDEWEB)

    Grezes, C.; Alzate, J. G.; Cai, X.; Wang, K. L. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Ebrahimi, F.; Khalili Amiri, P. [Department of Electrical Engineering, University of California, Los Angeles, California 90095 (United States); Inston, Inc., Los Angeles, California 90024 (United States); Katine, J. A. [HGST, Inc., San Jose, California 95135 (United States); Langer, J.; Ocker, B. [Singulus Technologies AG, Kahl am Main 63796 (Germany)

    2016-01-04

    We report electric-field-induced switching with write energies down to 6 fJ/bit for switching times of 0.5 ns, in nanoscale perpendicular magnetic tunnel junctions (MTJs) with high resistance-area product and diameters down to 50 nm. The ultra-low switching energy is made possible by a thick MgO barrier that ensures negligible spin-transfer torque contributions, along with a reduction of the Ohmic dissipation. We find that the switching voltage and time are insensitive to the junction diameter for high-resistance MTJs, a result accounted for by a macrospin model of purely voltage-induced switching. The measured performance enables integration with same-size CMOS transistors in compact memory and logic integrated circuits.

  15. Fotosíntesis en tres poblaciones altitudinales de la planta andina Espeletia schultzii (Compositae

    Directory of Open Access Journals (Sweden)

    Marisol Castrillo

    2006-12-01

    Full Text Available Resumen Se establece una comparación de algunos parámetros fotosintéticos: actividad Rubisco (Ribulosa 1, 5-bis-fosfato carboxilasa EC 4.1.1.39 contenidos de clorofilas, azúcares solubles totales y proteínas solubles totales y área foliar específica (AFE, en tres poblaciones altitudinales de Espeletia schultzii ubicadas a 3 100, 3 550 y 4 200 msnm. De acuerdo con el análisis de varianza la población a 4 200 m presentó una actividad Rubisco significativamente mayor que las otras dos, en cuyos casos los valores no fueron diferentes. Los contenidos de clorofila a presentan una leve tendencia a la disminución con la altura; mientras que la clorofila b se mantiene constante, razón por la cual la relación a/b (R a/b disminuye con la elevación, aunque, las diferencias no son significativas. El contenido de azúcares en cada una de las poblaciones estudiadas (gm-2, aumenta con la elevación; las diferencias entre las poblaciones son significativas. Con relación al contenido de proteínas, no existen diferencias entre las poblaciones estudiadas. El área foliar específica (AFE disminuye significativamente con la altura. Es probable que el incremento en la actividad Rubisco sea producido por una mayor activación de la enzima y no por el mayor contenido de proteína. Los azúcares solubles presentan incremento significativo, este hecho es probable que se encuentre asociado con la actividad Rubisco. De los cinco parámetros fotosintéticos medidos, tres presentan diferencias significativas asociadas con la altitud. Esto representa un compromiso entre una mayor actividad metabólica mantenida en un menor volumen celularPhotosynthesis in three altitudinal populations of the Andean plant Espeletia schultzii (Compositae. Photosynthesis was compared in three altitudinal populations of Espeletia schultzii: 3 100, 3 550 and 4 200 masl. The measured parameters were Rubisco activity (EC 4.1.139, chlorophyll, soluble protein and soluble sugars

  16. LC-PDA-ESI/MS Identification of the Phenolic Components of Three Compositae Spices: Chamomile, Tarragon, and Mexican Arnica

    Science.gov (United States)

    Chamomile (Matricaria chamomilla L.), tarragon (Artemisia dracunculus L.) and Mexican arnica (Heterotheca inuoides) are common compositae spices and herbs found in the US market. They contain flavonoids and hydroxycinnamates that are potentially beneficial to human health. A standardized LC-PDA-ESI...

  17. On five Compositae taxa which are confusingly illustrated in fl oristic publications for Andorra

    Directory of Open Access Journals (Sweden)

    Von Raab-Straube, E.

    2009-12-01

    Full Text Available Five Compositae taxa which are illustrated in floristic publications for Andorra are questionable records which appear to have never been collected there in the wild.

    Se comentan cinco taxones de compuestas que aparecen confusamente ilustrados en publicaciones florísticas de Andorra y que nunca se han recolectado en territorio andorrano.

  18. Sobre la circunscripción y posición taxonómica de Centaurea caballeroi (Compositae [On the circumscription and taxonomic status of Centaurea caballeroi (Compositae

    Directory of Open Access Journals (Sweden)

    Llorenç Sáez Goñalons

    2012-07-01

    Full Text Available RESUMEN: Se aportan datos sobre algunos táxones del grupo de Centaurea linifolia presentes en las sierras de la Comunidad Valenciana y áreas limítrofes. Como resultado se propone reconocer en C. antennata tres subespecies, con síndromes de caracteres propios, que ocupan áreas geográficas bien delimitadas y presentan un comportamiento ecológico diferenciado. Según esto, se propone la nueva combinación C. antennata subsp. caballeroi para las poblaciones del sur de Tarragona y norte de Castellón, seleccionándose además un lectótipo. Para cada taxon aceptado se indican sus caracteres morfológicos diferenciales, distribución y ecología. Además, se aporta una clave de identificación. SUMMARY: On the circumscription and taxonomic status of Centaurea caballeroi (Compositae: Data are reported on several taxa of the aggregate of Centaurea linifolia that grow in the mountains of the Valencian Community and neighboring areas. As a result, in the complex of C. antennata three taxa are accepted at the subspecific rank, which have their own syndromes of morphological characters, occur in well-defined territories and show different ecological behavior. The new combination C. antennata subsp. caballeroi is stated to name populations from southern Tarragona and northern Castellón provinces. Moreover, a lectotype is selected for the latter name. For each accepted taxon, its diagnostic morphological traits, distribution and ecology are commented. An identification key is also presented.

  19. Revisión del género PerezIa (compositae

    Directory of Open Access Journals (Sweden)

    Liliana Katinas

    2012-06-01

    Full Text Available El género Perezia Lag. (Compositae se compone de 30 especies de hierbas perennes distribuidas principalmente en la región andino-patagónica, desde Colombia hasta el sur de Argentina y Chile, con algunas especies en el este de Brasil y de la Argentina, Paraguay y Uruguay. Sus corolas bilabiadas, anteras sagitadas, estilos truncados con una coronita apical de pelos colectores y su estructura polínica ubican al género en la tribu Nassauvieae, subfamilia Mutisioideae. Se propone en este trabajo: a la rehabilitación de Perezia atacamensis, P. burkartii y P. capito; b la transferencia de P. ciliosa var. dentata a la categoría de especie [P. dentata (Cabrera comb. nov.]; c la inclusión de Perezia catharinensis Cabrera, P. eryngioides (Cabrera Crisci y P. volcanensis Cabrera, descritas o transferidas posteriormente a la primer revisión del género en 1969; d la eliminación de subespecies en P. lactucoides; e el establecimiento de la sinonimia entre P. pinnatifida, P. pygmaea y P. coerulescens; f el establecimiento de la sinonimia entre P. pungens, P. ciliaris, P. mandonii, P. purpurata, P. carduncelloides y P. sublyrata; g la rehabilitación de Perezia recurvata subsp. recurvata, subsp. beckii y subsp. triceps. Se designaron dos lectotipos y cinco neotipos, y se excluyeron 86 nombres del género.Revision of the genus Perezia (Compositae. The genus Perezia Lag. (Compositae, with 30 species, is distributed in the Andean-Patagonian region from Colombia to southern Argentina and Chile, and in eastern Brasil and Argentina, Paraguay and Uruguay. It belongs to the tribe Nassauvieae, subfamily Mutisioideae by its bilabiate corollas, caudate anthers, truncate style branches with a crown of collector hairs, and a particular pollen structure. It is proposed in this paper: a the rehabilitation of Perezia atacamensis, P. burkartii, and P. capito; b the change of P. ciliosa var. dentata to the species category [P. dentata (Cabrera comb. nov.]; c the

  20. Gap Junctions

    Science.gov (United States)

    Nielsen, Morten Schak; Axelsen, Lene Nygaard; Sorgen, Paul L.; Verma, Vandana; Delmar, Mario; Holstein-Rathlou, Niels-Henrik

    2013-01-01

    Gap junctions are essential to the function of multicellular animals, which require a high degree of coordination between cells. In vertebrates, gap junctions comprise connexins and currently 21 connexins are known in humans. The functions of gap junctions are highly diverse and include exchange of metabolites and electrical signals between cells, as well as functions, which are apparently unrelated to intercellular communication. Given the diversity of gap junction physiology, regulation of gap junction activity is complex. The structure of the various connexins is known to some extent; and structural rearrangements and intramolecular interactions are important for regulation of channel function. Intercellular coupling is further regulated by the number and activity of channels present in gap junctional plaques. The number of connexins in cell-cell channels is regulated by controlling transcription, translation, trafficking, and degradation; and all of these processes are under strict control. Once in the membrane, channel activity is determined by the conductive properties of the connexin involved, which can be regulated by voltage and chemical gating, as well as a large number of posttranslational modifications. The aim of the present article is to review our current knowledge on the structure, regulation, function, and pharmacology of gap junctions. This will be supported by examples of how different connexins and their regulation act in concert to achieve appropriate physiological control, and how disturbances of connexin function can lead to disease. © 2012 American Physiological Society. Compr Physiol 2:1981-2035, 2012. PMID:23723031

  1. First record of the alien pest Rhaponticum repens (Compositae in the Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    Martínez-Flores, F.

    2011-12-01

    Full Text Available First record of the alien pest Rhaponticum repens (Compositae in the Iberian Peninsula.- Rhaponticum repens is reported for the first time for the flora of the Iberian Peninsula. The species is native from Central Asia and has become invasive in Argentina, Canada, Europe and the USA. It was detected for the first time in abandoned fields from Vilablareix, near the city of Girona (Catalonia, Spain and in the valley of the Vinalopó in Alicante (Valencia, Spain, where it was collected as early as in 1959 but misdentified. Molecular data, based on nrDNA region ITS, suggest that the reported populations may be closely related to plants from the United States. Due to the extremely noxious character of the species and the possible relationship of Spanish plants with the invasive American populations, some kind of monitoring is recommended.Rhaponticum repens (Compositae, una nueva planta alóctona para la Península Ibérica.- Se cita por primera vez la especie Rhaponticum repens para la flora de la Península Ibérica. Rhaponticum repens es una especie nativa de Asia central que actúa como invasora en diversos países como Argentina, Canadá o los Estados Unidos. Se ha encontrado por primera vez en campos de cultivo abandonados en el pueblo de Vilablareix, cerca de la ciudad de Girona (Cataluña, España y en el valle del Vinalopó (Valencia, España, donde fue recolectada y mal identificada en 1959. Los datos moleculares, obtenidos a partir de la región ITS del nrDNA, sugieren que estas poblaciones podrían estar relacionadas con plantas invasoras de Estados Unidos. Debido al carácter extremadamente invasor de la especie, y a su posible origen secundario a partir de las poblaciones norteamericanas, se recomienda el seguimiento de estas poblaciones.

  2. Aerial radiological survey of the area surrounding the UNC Recovery Systems Facility, Wood River Junction, Rhode Island. Date of survey: August 1979

    International Nuclear Information System (INIS)

    1979-12-01

    An aerial radiological survey to measure terrestrial gamma radiation was carried out over the UNC Recovery Systems facility located near Wood River Junction, Rhode Island. At the time of the survey (August 1979) materials were being processed at the facility. Gamma ray data were collected over a 3.63 km 2 area centered on the facility by flying north-south lines spaced 60 m apart. Processed data indicated that detected radioisotopes and their associated gamma ray exposure rates were consistent with those expected from normal background emitters, except at certain locations described in this report. Average exposure rates 1 m above the ground, as calculated from the aerial data, are presented in the form of an isopleth map. No ground sample data were taken at the time of the aerial survey

  3. Effects of cadmium stress on growth and amino acid metabolism in two Compositae plants.

    Science.gov (United States)

    Zhu, Guangxu; Xiao, Huayun; Guo, Qingjun; Zhang, Zhongyi; Zhao, Jingjing; Yang, Dan

    2018-08-30

    Cadmium, a high toxic heavy metal, is one of the most serious contaminants in soil and a potential threat to plant growth and human health. Amino acid metabolism has the central role in heavy metal stress resistance of plants. In this paper, a pot experiment was carried out to study the effects of different concentrations of cadmium (0, 3, 6, 12, 30 mg kg -1 ) on the growth, Cd accumulation and amino acid metabolism in two Compositae plants (Ageratum conyzoides L. and Crassocephalum crepidioides). The results showed that under cadmium stress, C. crepidioides accumulated more Cd in its shoot and was tolerant to Cd, whereas its low Cd-accumulating relative, A. conyzoides, suffered reduced growth. The Cd content in the aerial part of C. crepidioides exceeded the threshold of Cd-hyperaccumulator. Furthermore, the bioaccumulation factor (BCF) and biological transfer factor (BTF) values for Cd in C. crepidioides were > 1. Thus, C. crepidioides can be regarded as Cd-hyperaccumulator. The comparison between both studied plants indicated that Cd stress resulted in a differential but coordinated response of amino acid levels, which are playing a significant role in plant adaptation to Cd stress. Glu, Gln, Asp, Asn, Gaba, Val and Ala dominated the major amino acids. Higher Cd tolerance and Cd accumulation in C. crepidioides was associated with greater accumulation of free amino acids, especially for Gln and Asn, in C. crepidioides than in A. conyzoides. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Solid State Large Area Pulsed Solar Simulator for 3-, 4- and 6-Junction Solar Cell Arrays, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase I was successful in delivering a complete prototype of the proposed innovation, an LED-based, solid state, large area, pulsed, solar simulator (ssLAPSS)....

  5. Fundamental study on turbulent fluid mixing characteristics in piping systems. Fundamental study on fluid mixing mechanism in T-junction areas

    International Nuclear Information System (INIS)

    Toda, Saburo; Yuki, Kazuhisa; Muramatsu, Toshiharu

    2002-03-01

    In a region where two fluids with different temperatures are mixed together, unsteady temperature fluctuation, i.e. thermal striping, occurs in going through the unstable mixing process of the fluids, and structural materials in the surrounding area may be damaged by high-cycle thermal fatigue. In this report, in order to clarify the relation between the thermal striping and temperature fluctuation of structural wall, PIV measuring system is applied to visualize the fluid mixing state in a T-junction area in which important parameters for the fluid mixing are the flow velocity and aperture ratios of a main pipe to a small pipe and an incidence angle of the small pipe to the main pipe as well as temperature difference of the two flows. As a result of visualization experiments in a isothermal field, it is confirmed that a jet-axis, which is a stream line flowing out from the center of the small pipe, vibrates unsteadily and that its behavior is strongly affected by circulating flow, Karman vortex formed behind the jet axis, and especially flow-fluctuation which exists as a background-flow in the main pipe. Especially, the frequency band of the flow-fluctuation in the main pipe almost corresponds to that of the vibration of the jet-axis where the ratio of flow rate is low. Furthermore, in order to estimate the vibration state of the jet-axis and to find out the conditions for preventing the thermal fatigue, the penetration depth of the jet-axis is generalized. From measurements of temperature fluctuation of wall, it is shown that a high power fluctuation area exists universally behind the junction point of the small pipe where the flow rate of the small pipe flow is relatively lower than that of the main pipe flow. The band of dominant frequency of the temperature fluctuation is almost the same as the flow-fluctuation and the jet-axis vibration mentioned above. In addition, visualization experiments of secondary flow formed in a 90-degree bend, which is installed

  6. Potentials of leaves of Aspilia africana (Compositae in wound care: an experimental evaluation

    Directory of Open Access Journals (Sweden)

    Akah PA

    2007-07-01

    Full Text Available Abstract Background The potentials of the leaves of the haemorrhage plant, Aspilia africana C. D Adams (Compositae in wound care was evaluated using experimental models. A. africana, which is widespread in Africa, is used in traditional medicine to stop bleeding from wounds, clean the surfaces of sores, in the treatment of rheumatic pains, bee and scorpion stings and for removal of opacities and foreign bodies from the eyes. The present study was undertaken to evaluate the potentials for use of leaves of this plant in wound care. Methods The effect of the methanol extract (ME and the hexane (HF and methanol (MF fractions (obtained by cold maceration and graded solvent extraction respectively on bleeding/clotting time of fresh experimentally-induced wounds in rats, coagulation time of whole rat blood, growth of microbial wound contaminants and rate of healing of experimentally-induced wounds in rats were studied as well as the acute toxicity and lethality (LD50 of the methanol extract and phytochemical analysis of the extract and fractions. Results The extract and fractions significantly (P ME>HF. Also, the extract and fractions caused varying degrees of inhibition of the growth of clinical isolates of Pseudomonas fluorescens and Staphylococcus aureus, as well as typed strains of Ps. aeruginosa (ATCC 10145 and Staph. aureus (ATCC 12600, and reduced epithelialisation period of wounds experimentally-induced in rats. Acute toxicity and lethality (LD50 test in mice established an i.p LD50 of 894 mg/kg for the methanol extract (ME. Phytochemical analysis revealed the presence of alkaloids, saponins, tannins, flavonoids, resins, sterols, terpenoids and carbohydrates. Conclusion The leaves of A. africana possess constituents capable of arresting wound bleeding, inhibiting the growth of microbial wound contaminants and accelerating wound healing which suggest good potentials for use in wound care.

  7. Multiscale Spatio-Temporal Dynamics of Economic Development in an Interprovincial Boundary Region: Junction Area of Tibetan Plateau, Hengduan Mountain, Yungui Plateau and Sichuan Basin, Southwestern China Case

    Directory of Open Access Journals (Sweden)

    Jifei Zhang

    2016-02-01

    Full Text Available An interprovincial boundary region is a new subject of economic disparity study in China. This study explored the multi-scale spatio-temporal dynamics of economic development from 1995 to 2010 in the interprovincial boundary region of Sichuan-Yunnan-Guizhou, a mountain area and also the junction area of Tibetan Plateau, Hengduan Mountain, Yungui Plateau and Sichuan Basin in southwestern China. A quantitative study on county GDP per capita for different scales of administrative regions was conducted using the Theil index, Markov chains, a geographic information system and exploratory spatial data analysis. Results indicated that the economic disparity was closely related with geographical unit scale in the study area: the smaller the unit, the bigger the disparity, and the regional inequality gradually weakened over time. Moreover, significant positive spatial autocorrelation and clustering of economic development were also found. The spatial pattern of economic development presented approximate circle structure with two cores in the southwest and northeast. The Panxi region in the southwest core and a part of Hilly Sichuan Basin in the northeast core were considered to be hot spots of economic development. Most areas in the east and central region were persistently trapped in the low level of a balanced development state, with a poverty trap being formed in the central and south part. Geographical conditions and location, administrative barriers and the lack of effective growth poles may be the main reasons for the entire low level of balanced development. Our findings suggest that in order to achieve a high level of balanced development, attention should be paid beyond developing transportation and other infrastructure. Breaking down the rigid shackles of administrative districts that hinder trans-provincial cooperation and promoting new regional poles in the Yunnan-Guizhou region may have great significance for the study area.

  8. Method of manufacturing Josephson junction integrated circuits

    International Nuclear Information System (INIS)

    Jillie, D.W. Jr.; Smith, L.N.

    1985-01-01

    Josephson junction integrated circuits of the current injection type and magnetically controlled type utilize a superconductive layer that forms both Josephson junction electrode for the Josephson junction devices on the integrated circuit as well as a ground plane for the integrated circuit. Large area Josephson junctions are utilized for effecting contact to lower superconductive layers and islands are formed in superconductive layers to provide isolation between the groudplane function and the Josephson junction electrode function as well as to effect crossovers. A superconductor-barrier-superconductor trilayer patterned by local anodization is also utilized with additional layers formed thereover. Methods of manufacturing the embodiments of the invention are disclosed

  9. Tunnel oxide passivated rear contact for large area n-type front junction silicon solar cells providing excellent carrier selectivity

    Directory of Open Access Journals (Sweden)

    Yuguo Tao

    2016-01-01

    Full Text Available Carrier-selective contact with low minority carrier recombination and efficient majority carrier transport is mandatory to eliminate metal-induced recombination for higher energy conversion efficiency for silicon (Si solar cells. In the present study, the carrier-selective contact consists of an ultra-thin tunnel oxide and a phosphorus-doped polycrystalline Si (poly-Si thin film formed by plasma enhanced chemical vapor deposition (PECVD and subsequent thermal crystallization. It is shown that the poly-Si film properties (doping level, crystallization and dopant activation anneal temperature are crucial for achieving excellent contact passivation quality. It is also demonstrated quantitatively that the tunnel oxide plays a critical role in this tunnel oxide passivated contact (TOPCON scheme to realize desired carrier selectivity. Presence of tunnel oxide increases the implied Voc (iVoc by ~ 125 mV. The iVoc value as high as 728 mV is achieved on symmetric structure with TOPCON on both sides. Large area (239 cm2 n-type Czochralski (Cz Si solar cells are fabricated with homogeneous implanted boron emitter and screen-printed contact on the front and TOPCON on the back, achieving 21.2% cell efficiency. Detailed analysis shows that the performance of these cells is mainly limited by boron emitter recombination on the front side.

  10. Actividad molusquicida del Piquerol A aislado de Piqueria trinervia (compositae sobre ocho especies de caracoles pulmonados The molluscicide activity of Piquerol A isolated from Piqueria trinervia (Compositae against eight species of pulmonate snails

    Directory of Open Access Journals (Sweden)

    Alejandro Cruz-Reys

    1989-03-01

    Full Text Available De las partes aéreas de la planta Piqueria trinervia (Compositae colectada en diveresas áereas de México, se aisló el Piquerol A. Este compuesto se probó como agente molusquicida contra ocho especies de caracoles pulmonados: Fossaria (Fossaria humilis, F. (Bakerilymnae sp., Pseudosuccinea columella, Stagnicola attenuata, de México; F. (B. cubensis y Physacubensis, de Cuba; P. Columella y Biomphalaria glabrata, de Brasil; B glabrata, de Puerto Rico; S. elodes, de Estados Unidos. Se utilizaron tres concentraciones 50, 25 y 5 ppm para cada una de las especies y 2 períodos de exposición, 6 y 24 horas, a 20-22ºC. En 50 ppm, después de 6 horas, y 25 ppm, después de 24 horas los ejemplares de todas las especies murieron. En 5 ppm después de 24 horas, se observaron mortalidades de 60 a 100%. En ningún caso se observó recuperación después de la exposición por 24 horas. El piquerol A es un terpeno biodegradable que presenta otras actividades biológicas. No se han hecho pruebas de toxicidad en otros animales ni pruebas de campo. Sin embargo, es una substacia con alto potencial de uso como molusquicida en zonas de transmisión focal. Es la primera que en México se hacen estudios sistemáticos sobre molusquicidas de origen vegetal.In laboratory trials an aqueous solution of Piquerol A from Piqueria trinervia, collected in several regions of Mexico, showed a molluscicide action on the adults of eight different pulmonates snails species. Fossaria (Fossaria humilis, F. (Bakerilymnaea sp., Pseudosuccinea columella and Stagnicola attenuata from Mexico; F. (B. cubensis and Physa cubensis from Cuba; P. columella and Biomphalaria glabrata from Brazil; B. glabrata from Puerto Rico; and S. elodes from USA. The solution was tested at 50, 25 and 5 ppm concentration, for two periods of 6 and 24 hours, at room temperature (20-22ºC. A 100% mortality was obtained for all species at 50 ppm concentration after 6 hours of exposure; the same percentage at 25

  11. Constituents of the arial parts of Eupatorium odoratum L. ( Syn. Chromolaena odorata) (L.) R.M. King And H Robinson), family compositae-grown in Vietnam

    NARCIS (Netherlands)

    Trang, N.T.D.; Phuong, L.V.N.; Dung, N.X.; Leclercq, P.A.; Wanner, M.J.; Koomen, C.J.; Fokkens, R.

    1994-01-01

    Eupatorium odoratum (L.), Family Compositae grows very fast in various places of the world, especially in tropical countries. This plant belonges to one of the worst plants. Some applications of this plant used for treatment of diseases such as disrrhoea, dysentery and scabies have been found in

  12. Contact sensitization to calocephalin, a sesquiterpene lactone of the guaianolide type from cushion bush (Leucophyta brownii, Compositae)

    DEFF Research Database (Denmark)

    Paulsen, Evy; Christensen, Lars P; Hindsén, Monica

    2013-01-01

    Cushion bush [Leucophyta brownii Cass. = Calocephalus brownii (Cass.) F. Muell.] is an Australian Compositae shrub that has been introduced into Scandinavia as a pot plant. The first case of sensitization occurred in a gardener, and the main allergen was identified as the guaianolide calocephalin....

  13. Measurement of esophago-gastric junction cross-sectional area and distensibility by an endolumenal functional lumen imaging probe for the diagnosis of gastro-esophageal reflux disease.

    Science.gov (United States)

    Tucker, E; Sweis, R; Anggiansah, A; Wong, T; Telakis, E; Knowles, K; Wright, J; Fox, M

    2013-11-01

    Measurement of esophago-gastric junction (EGJ) cross-sectional area (CSA) and distensibility by an Endolumenal Functional Lumen Imaging Probe (EndoFLIP®) may distinguish between gastro-esophageal reflux disease (GERD) patients and healthy volunteers (HV). We aimed to assess the agreement of EndoFLIP® measurements with clinical and physiologic diagnosis of GERD. Twenty-one HV and 18 patients with typical GERD symptoms were studied. After gastroscopy, EGJ CSA, and distensibility were measured by EndoFLIP®. Forty-eight hour esophageal pH monitoring was then performed by a wireless system. The ability of EndoFLIP® to discriminate GERD patient and HVs was assessed. Planned secondary analysis then assessed whether EGJ CSA and distensibility were increased in individuals with pathologic acid exposure. Healthy volunteers were younger and had lower body mass index (BMI; both p < 0.001). Pathologic acid exposure was present in 3/21 (14%) HVs and 9/18 (50%) patients (p = 0.126). At 30 mL EndoFLIP® bag volume, EGJ CSA was higher (p = 0.058) and EGJ distensibility was lower (p = 0.020) in HVs than patients. Secondary analysis showed that EGJ measurements were similar in participants with and without pathologic acid exposure (CSA 98 mm² vs 107 mm²; p = 0.789, distensibility; p = 0.704). An inverse association between BMI and CSA (R² = 0.2758, p = 0.001) and distensibility (R² = 0.2005, p = 0.005) was present. Endolumenal Functional Lumen Imaging Probe is not useful for GERD diagnosis because EGJ CSA and distensibility do not distinguish between HVs and GERD patients defined by clinical presentation or pH measurement. This unexpected result may be due to an important, confounding interaction of obesity. © 2013 John Wiley & Sons Ltd.

  14. Josephson junctions with ferromagnetic interlayer

    International Nuclear Information System (INIS)

    Wild, Georg Hermann

    2012-01-01

    We report on the fabrication of superconductor/insulator/ferromagnetic metal/superconductor (Nb/AlO x /Pd 0.82 Ni 0.18 /Nb) Josephson junctions (SIFS JJs) with high critical current densities, large normal resistance times area products, and high quality factors. For these junctions, a transition from 0- to π-coupling is observed for a thickness d F =6 nm of the ferromagnetic Pd 0.82 Ni 0.18 interlayer. The magnetic field dependence of the critical current of the junctions demonstrates good spatial homogeneity of the tunneling barrier and ferromagnetic interlayer. Magnetic characterization shows that the Pd 0.82 Ni 0.18 has an out-of-plane anisotropy and large saturation magnetization indicating negligible dead layers at the interfaces. A careful analysis of Fiske modes up to about 400 GHz provides valuable information on the junction quality factor and the relevant damping mechanisms. Whereas losses due to quasiparticle tunneling dominate at low frequencies, at high frequencies the damping is explained by the finite surface resistance of the junction electrodes. High quality factors of up to 30 around 200 GHz have been achieved. They allow to study the junction dynamics, in particular the switching probability from the zero-voltage into the voltage state with and without microwave irradiation. The experiments with microwave irradiation are well explained within semi-classical models and numerical simulations. In contrast, at mK temperature the switching dynamics without applied microwaves clearly shows secondary quantum effects. Here, we could observe for the first time macroscopic quantum tunneling in Josephson junctions with a ferromagnetic interlayer. This observation excludes fluctuations of the critical current as a consequence of an unstable magnetic domain structure of the ferromagnetic interlayer and affirms the suitability of SIFS Josephson junctions for quantum information processing.

  15. Josephson junctions with ferromagnetic interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Wild, Georg Hermann

    2012-03-04

    We report on the fabrication of superconductor/insulator/ferromagnetic metal/superconductor (Nb/AlO{sub x}/Pd{sub 0.82}Ni{sub 0.18}/Nb) Josephson junctions (SIFS JJs) with high critical current densities, large normal resistance times area products, and high quality factors. For these junctions, a transition from 0- to {pi}-coupling is observed for a thickness d{sub F}=6 nm of the ferromagnetic Pd{sub 0.82}Ni{sub 0.18} interlayer. The magnetic field dependence of the critical current of the junctions demonstrates good spatial homogeneity of the tunneling barrier and ferromagnetic interlayer. Magnetic characterization shows that the Pd{sub 0.82}Ni{sub 0.18} has an out-of-plane anisotropy and large saturation magnetization indicating negligible dead layers at the interfaces. A careful analysis of Fiske modes up to about 400 GHz provides valuable information on the junction quality factor and the relevant damping mechanisms. Whereas losses due to quasiparticle tunneling dominate at low frequencies, at high frequencies the damping is explained by the finite surface resistance of the junction electrodes. High quality factors of up to 30 around 200 GHz have been achieved. They allow to study the junction dynamics, in particular the switching probability from the zero-voltage into the voltage state with and without microwave irradiation. The experiments with microwave irradiation are well explained within semi-classical models and numerical simulations. In contrast, at mK temperature the switching dynamics without applied microwaves clearly shows secondary quantum effects. Here, we could observe for the first time macroscopic quantum tunneling in Josephson junctions with a ferromagnetic interlayer. This observation excludes fluctuations of the critical current as a consequence of an unstable magnetic domain structure of the ferromagnetic interlayer and affirms the suitability of SIFS Josephson junctions for quantum information processing.

  16. 40Ar/39Ar thermo-chronology and lithospheric mechanisms. Methodological and applied approach: the Kunlun range (Asia) and the Afar triple junction area (East Africa)

    International Nuclear Information System (INIS)

    Mock, C.

    1998-01-01

    A 40 Ar/ 39 Ar thermo-chronological study has been carried out for two contrasted geodynamic settings: - the Eastern Kunlun range (Northern Tibet), in order to characterize the lithospheric deformation mechanisms related to the India-Asia collision; - the Afar triple junction area (East Africa), in order to constrain the timing of mantle plume-related basement uplift in Ethiopia and Yemen, which will indicate whether rifting was active or passive. In the Kunlun, the cooling event (9-15 deg.C/Ma) outlined at 30 Ma for the granitoids (Bt = 128-138 Ma; Kf = 102-147 Ma) reflects a denudation event (0.2-0.3 km/Ma), related to ramp stacking and normal faulting with associated uplift. This unroofing period is coeval with the great Asian strike-slip faults. This suggests that 30 Ma ago, the India-Asia collision was accommodated by lateral extrusion along great strike-slip faults, which might have led to local crustal thickening because of the formation of anticlines from major thrusts 'branching' from the Kunlun fault. In the Afar area the Panafrican basement (granitoids = 462-678 Ma;metamorphic rocks 505-750 Ma) has undergone a reheating event during the Cenozoic; its temperature is estimated around 138-177 deg.C over the last 50 Ma for a depth of 2 km, implying a thermal gradient of 69-88 deg./km. This reheating event results from both heat conduction, related to the mantle plume. and heat advection. because of magma transfer. However, it was not possible to define the timing of the mantle plume-related basement uplift. This study outlines the important thermal effect of continental flood basalts on the crust and suggests that the 40 Ar/ 39 Ar thermo-chronology does not allow to characterize the denudation of the lithosphere for an extension-type geodynamic setting. Finally, some of the results suggest that diffusion in the laboratory and in nature may be different. 40 Ar/ 39 Ar thermo-chronological analysis thus might be tricky, especially in investigating geologic

  17. al junctions

    African Journals Online (AJOL)

    Preferred Customer

    Capacitance per unit area as well as the width of the depletion layer are obtained from the complex impedance analysis. ... Thermo ionic emission theory is applied to extract the parameters. .... limit is usually obtained by extrapolation. The.

  18. Molecular electronic junction transport

    DEFF Research Database (Denmark)

    Solomon, Gemma C.; Herrmann, Carmen; Ratner, Mark

    2012-01-01

    Whenasinglemolecule,oracollectionofmolecules,isplacedbetween two electrodes and voltage is applied, one has a molecular transport junction. We discuss such junctions, their properties, their description, and some of their applications. The discussion is qualitative rather than quantitative, and f...

  19. Macroscopic quantum tunneling in Josephson tunnel junctions and Coulomb blockade in single small tunnel junctions

    International Nuclear Information System (INIS)

    Cleland, A.N.

    1991-04-01

    Experiments investigating the process of macroscopic quantum tunneling in a moderately-damped, resistively shunted, Josephson junction are described, followed by a discussion of experiments performed on very small capacitance normal-metal tunnel junctions. The experiments on the resistively-shunted Josephson junction were designed to investigate a quantum process, that of the tunneling of the Josephson phase variable under a potential barrier, in a system in which dissipation plays a major role in the dynamics of motion. All the parameters of the junction were measured using the classical phenomena of thermal activation and resonant activation. Theoretical predictions are compared with the experimental results, showing good agreement with no adjustable parameters; the tunneling rate in the moderately damped (Q ∼ 1) junction is seen to be reduced by a factor of 300 from that predicted for an undamped junction. The phase is seen to be a good quantum-mechanical variable. The experiments on small capacitance tunnel junctions extend the measurements on the larger-area Josephson junctions from the region in which the phase variable has a fairly well-defined value, i.e. its wavefunction has a narrow width, to the region where its value is almost completely unknown. The charge on the junction becomes well-defined and is predicted to quantize the current through the junction, giving rise to the Coulomb blockade at low bias. I present the first clear observation of the Coulomb blockade in single junctions. The electrical environment of the tunnel junction, however, strongly affects the behavior of the junction: higher resistance leads are observed to greatly sharpen the Coulomb blockade over that seen with lower resistance leads. I present theoretical descriptions of how the environment influences the junctions; comparisons with the experimental results are in reasonable agreement

  20. Junction and circuit fabrication

    International Nuclear Information System (INIS)

    Jackel, L.D.

    1980-01-01

    Great strides have been made in Josephson junction fabrication in the four years since the first IC SQUID meeting. Advances in lithography have allowed the production of devices with planar dimensions as small as a few hundred angstroms. Improved technology has provided ultra-high sensitivity SQUIDS, high-efficiency low-noise mixers, and complex integrated circuits. This review highlights some of the new fabrication procedures. The review consists of three parts. Part 1 is a short summary of the requirements on junctions for various applications. Part 2 reviews intergrated circuit fabrication, including tunnel junction logic circuits made at IBM and Bell Labs, and microbridge radiation sources made at SUNY at Stony Brook. Part 3 describes new junction fabrication techniques, the major emphasis of this review. This part includes a discussion of small oxide-barrier tunnel junctions, semiconductor barrier junctions, and microbridge junctions. Part 3 concludes by considering very fine lithography and limitations to miniaturization. (orig.)

  1. Fabrication of Josephson Junction without shadow evaporation

    Science.gov (United States)

    Wu, Xian; Ku, Hsiangsheng; Long, Junling; Pappas, David

    We developed a new method of fabricating Josephson Junction (Al/AlOX/Al) without shadow evaporation. Statistics from room temperature junction resistance and measurement of qubits are presented. Unlike the traditional ``Dolan Bridge'' technique, this method requires two individual lithographies and straight evaporations of Al. Argon RF plasma is used to remove native AlOX after the first evaporation, followed by oxidation and second Al evaporation. Junction resistance measured at room temperature shows linear dependence on Pox (oxidation pressure), √{tox} (oxidation time), and inverse proportional to junction area. We have seen 100% yield of qubits made with this method. This method is promising because it eliminates angle dependence during Junction fabrication, facilitates large scale qubits fabrication.

  2. Quantum synchronization effects in intrinsic Josephson junctions

    International Nuclear Information System (INIS)

    Machida, M.; Kano, T.; Yamada, S.; Okumura, M.; Imamura, T.; Koyama, T.

    2008-01-01

    We investigate quantum dynamics of the superconducting phase in intrinsic Josephson junctions of layered high-T c superconductors motivated by a recent experimental observation for the switching rate enhancement in the low temperature quantum regime. We pay attention to only the capacitive coupling between neighboring junctions and perform large-scale simulations for the Schroedinger equation derived from the Hamiltonian considering the capacitive coupling alone. The simulation focuses on an issue whether the switching of a junction induces those of the other junctions or not. The results reveal that the superconducting phase dynamics show synchronous behavior with increasing the quantum character, e.g., decreasing the junction plane area and effectively the temperature. This is qualitatively consistent with the experimental result

  3. Atomic-scaled characterization of graphene PN junctions

    Science.gov (United States)

    Zhou, Xiaodong; Wang, Dennis; Dadgar, Ali; Agnihotri, Pratik; Lee, Ji Ung; Reuter, Mark C.; Ross, Frances M.; Pasupathy, Abhay N.

    Graphene p-n junctions are essential devices for studying relativistic Klein tunneling and the Veselago lensing effect in graphene. We have successfully fabricated graphene p-n junctions using both lithographically pre-patterned substrates and the stacking of vertical heterostructures. We then use our 4-probe STM system to characterize the junctions. The ability to carry out scanning electron microscopy (SEM) in our STM instrument is essential for us to locate and measure the junction interface. We obtain both the topography and dI/dV spectra at the junction area, from which we track the shift of the graphene chemical potential with position across the junction interface. This allows us to directly measure the spatial width and roughness of the junction and its potential barrier height. We will compare the junction properties of devices fabricated by the aforementioned two methods and discuss their effects on the performance as a Veselago lens.

  4. Equivalent Josephson junctions

    International Nuclear Information System (INIS)

    Boyadzhiev, T.L.; ); Semerdzhieva, E.G.; Shukrinov, Yu.M.; Fiziko-Tekhnicheskij Inst., Dushanbe

    2008-01-01

    The magnetic field dependences of critical current are numerically constructed for a long Josephson junction with a shunt- or resistor-type microscopic inhomogeneities and compared to the critical curve of a junction with exponentially varying width. The numerical results show that it is possible to replace the distributed inhomogeneity of a long Josephson junction by an inhomogeneity localized at one of its ends, which has certain technological advantages. It is also shown that the critical curves of junctions with exponentially varying width and inhomogeneities localized at the ends are unaffected by the mixed fluxon-antifluxon distributions of the magnetic flux [ru

  5. Protease-inhibiting, molecular modeling and antimicrobial activities of extracts and constituents from Helichrysum foetidum and Helichrysum mechowianum (compositae).

    Science.gov (United States)

    Malolo, Fanny-Aimée Essombe; Bissoue Nouga, Achille; Kakam, Antoine; Franke, Katrin; Ngah, Lidwine; Flausino, Otavio; Mpondo Mpondo, Emmanuel; Ntie-Kang, Fidele; Ndom, Jean Claude; Bolzani, Vanderlan da Silva; Wessjohann, Ludger

    2015-01-01

    from Helichrysum species (Compositae).

  6. Supramolecular tunneling junctions

    NARCIS (Netherlands)

    Wimbush, K.S.

    2012-01-01

    In this study a variety of supramolecular tunneling junctions were created. The basis of these junctions was a self-assembled monolayer of heptathioether functionalized ß-cyclodextrin (ßCD) formed on an ultra-flat Au surface, i.e., the bottom electrode. This gave a well-defined hexagonally packed

  7. Circulating and in situ lymphocyte subsets and Langerhans cells in patients with compositae oleoresin dermatitis and increased ultraviolet A sensitivity during treatment with azathioprine

    International Nuclear Information System (INIS)

    Baadsgaard, O.

    1986-01-01

    Circulating and in situ lymphocyte subsets and Langerhans cells in four patients with compositae oleoresin dermatitis and increased ultraviolet A sensitivity before and during treatment with azathioprine were estimated. It was found that the number of Leu 6+ Langerhans cells decreased during therapy. This decrease was accompanied by a reduction in the number of Leu 2a+, Leu 3a+, Leu 4+, DR+, and Leu M2+ cells in the blood and a reduction in the number of Leu 2a+, Leu 3a+, Leu 4+, and DR+ cells in the skin. Concomitantly with the changes in the number of immunocompetent cells, the eczema cleared

  8. Macroscopic quantum tunneling in Josephson tunnel junctions and Coulomb blockade in single small tunnel junctions

    International Nuclear Information System (INIS)

    Cleland, A.N.

    1991-01-01

    Experiments investigated the process of macroscopic quantum tunneling in a moderately-damped, resistively shunted, Josephson junction are described, followed by a discussion of experiments performed on very-small-capacitance normal-metal tunnel junctions. The experiments on the resistively-shunted Josephson junction were designed to investigate a quantum process, that of the tunneling of the Josephson-phase variable under a potential barrier, in a system in which dissipation plays a major role in the dynamics of motion. All the parameters of the junction were measured using the classical phenomena of thermal activation and resonant activation. Theoretical predictions are compared with the experimental results, showing good agreement with no adjustable parameters. The experiments on small-capacitance tunnel junctions extend the measurements on the large-area Josephson junctions from the region in which the phase variable has a fairly well-defined value, i.e. its wave function has a narrow width, to the region where its value is almost completely unknown. The charge on the junction becomes well-defined and is predicted to quantize the current through the junction, giving rise to the Coulomb blockade at low bias

  9. Superconducting tunnel-junction refrigerator

    International Nuclear Information System (INIS)

    Melton, R.G.; Paterson, J.L.; Kaplan, S.B.

    1980-01-01

    The dc current through an S 1 -S 2 tunnel junction, with Δ 2 greater than Δ 1 , when biased with eV 1 +Δ 2 , will lower the energy in S 1 . This energy reduction will be shared by the phonons and electrons. This device is shown to be analogous to a thermoelectric refrigerator with an effective Peltier coefficient π* approx. Δ 1 /e. Tunneling calculations yield the cooling power P/sub c/, the electrical power P/sub e/ supplied by the bias supply, and the cooling efficiency eta=P/sub c//P/sub e/. The maximum cooling power is obtained for eV= +- (Δ 2 -Δ 1 ) and t 1 =T 1 /T/sub c/1 approx. 0.9. Estimates are made of the temperature difference T 2 -T 1 achievable in Al-Pb and Sn-Pb junctions with an Al 2 O 3 tunneling barrier. The performance of this device is shown to yield a maximum cooling efficiency eta approx. = Δ 1 /(Δ 2 -Δ 1 ) which can be compared with that available in an ideal Carnot refrigerator of eta=T 1 /(T 2 -T 1 ). The development of a useful tunnel-junction refrigerator requires a tunneling barrier with an effective thermal conductance per unit area several orders of magnitude less than that provided by the A1 2 O 3 barrier in the Al-Pb and Sn-Pb systems

  10. Primary Tunnel Junction Thermometry

    International Nuclear Information System (INIS)

    Pekola, Jukka P.; Holmqvist, Tommy; Meschke, Matthias

    2008-01-01

    We describe the concept and experimental demonstration of primary thermometry based on a four-probe measurement of a single tunnel junction embedded within four arrays of junctions. We show that in this configuration random sample specific and environment-related errors can be avoided. This method relates temperature directly to Boltzmann constant, which will form the basis of the definition of temperature and realization of official temperature scales in the future

  11. Quantum Junction Solar Cells

    KAUST Repository

    Tang, Jiang

    2012-09-12

    Colloidal quantum dot solids combine convenient solution-processing with quantum size effect tuning, offering avenues to high-efficiency multijunction cells based on a single materials synthesis and processing platform. The highest-performing colloidal quantum dot rectifying devices reported to date have relied on a junction between a quantum-tuned absorber and a bulk material (e.g., TiO 2); however, quantum tuning of the absorber then requires complete redesign of the bulk acceptor, compromising the benefits of facile quantum tuning. Here we report rectifying junctions constructed entirely using inherently band-aligned quantum-tuned materials. Realizing these quantum junction diodes relied upon the creation of an n-type quantum dot solid having a clean bandgap. We combine stable, chemically compatible, high-performance n-type and p-type materials to create the first quantum junction solar cells. We present a family of photovoltaic devices having widely tuned bandgaps of 0.6-1.6 eV that excel where conventional quantum-to-bulk devices fail to perform. Devices having optimal single-junction bandgaps exhibit certified AM1.5 solar power conversion efficiencies of 5.4%. Control over doping in quantum solids, and the successful integration of these materials to form stable quantum junctions, offers a powerful new degree of freedom to colloidal quantum dot optoelectronics. © 2012 American Chemical Society.

  12. Effect of solar-cell junction geometry on open-circuit voltage

    Science.gov (United States)

    Weizer, V. G.; Godlewski, M. P.

    1985-01-01

    Simple analytical models have been found that adequately describe the voltage behavior of both the stripe junction and dot junction grating cells as a function of junction area. While the voltage in the former case is found to be insensitive to junction area reduction, significant voltage increases are shown to be possible for the dot junction cell. With regard to cells in which the junction area has been increased in a quest for better performance, it was found that (1) texturation does not affect the average saturation current density J0, indicating that the texturation process is equivalent to a simple extension of junction area by a factor of square root of 3 and (2) the vertical junction cell geometry produces a sizable decrease in J0 that, unfortunately, is more than offset by the effects of attendant areal increases.

  13. Four-junction superconducting circuit

    Science.gov (United States)

    Qiu, Yueyin; Xiong, Wei; He, Xiao-Ling; Li, Tie-Fu; You, J. Q.

    2016-01-01

    We develop a theory for the quantum circuit consisting of a superconducting loop interrupted by four Josephson junctions and pierced by a magnetic flux (either static or time-dependent). In addition to the similarity with the typical three-junction flux qubit in the double-well regime, we demonstrate the difference of the four-junction circuit from its three-junction analogue, including its advantages over the latter. Moreover, the four-junction circuit in the single-well regime is also investigated. Our theory provides a tool to explore the physical properties of this four-junction superconducting circuit. PMID:27356619

  14. Tunable Nitride Josephson Junctions.

    Energy Technology Data Exchange (ETDEWEB)

    Missert, Nancy A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Henry, Michael David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lewis, Rupert M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Howell, Stephen W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wolfley, Steven L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brunke, Lyle Brent [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wolak, Matthaeus [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-12-01

    We have developed an ambient temperature, SiO2/Si wafer - scale process for Josephson junctions based on Nb electrodes and Ta x N barriers with tunable electronic properties. The films are fabricated by magnetron sputtering. The electronic properties of the TaxN barriers are controlled by adjusting the nitrogen flow during sputtering. This technology offers a scalable alternative to the more traditional junctions based on AlOx barriers for low - power, high - performance computing.

  15. Characterization of magnetic tunnel junction test pads

    DEFF Research Database (Denmark)

    Østerberg, Frederik Westergaard; Kjær, Daniel; Nielsen, Peter Folmer

    2015-01-01

    We show experimentally as well as theoretically that patterned magnetic tunnel junctions can be characterized using the current-in-plane tunneling (CIPT) method, and the key parameters, the resistance-area product (RA) and the tunnel magnetoresistance (TMR), can be determined. The CIPT method...

  16. Superconductive junctions for x-ray spectroscopy

    International Nuclear Information System (INIS)

    Grand, J.B. le; Bruijn, M.P.; Frericks, M.; Korte, P.A.J. de; Houwman, E.P.; Flokstra, J.

    1992-01-01

    Biasing of SIS-junctions for the purpose of high energy resolution x-ray detection is complicated by the presence of a DC Josephson current and AC Josephson current resonances, so that a large magnetic field is normally used for the suppression of these Josephson features. A transimpedance amplifier is proposed for biasing and signal amplification at low magnetic field. X-ray spectroscopy detectors for astronomy require a high detection efficiency in the 0.5-10 keV energy band and a reasonable (∼1 cm 2 ) detector area. Calculations on absorber-junctions combinations which might meet these requirements are presented. (author) 9 refs.; 10 figs

  17. Field modulation of the critical current in magnetic Josephson junctions

    International Nuclear Information System (INIS)

    Blamire, M G; Smiet, C B; Banerjee, N; Robinson, J W A

    2013-01-01

    The dependence of the critical current of a simple Josephson junction on the applied magnetic field is well known and, for a rectangular junction, gives rise to the classic ‘Fraunhofer’ modulation with periodic zeros at the fields that introduce a flux quantum into the junction region. Much recent work has been performed on Josephson junctions that contain magnetic layers. The magnetization of such layers introduces additional flux into the junction and, for large junction areas or strong magnetic materials, can significantly distort the modulation of the critical current and strongly suppress the maximum critical current. The growing interest in junctions that induce odd-frequency triplet pairing in a ferromagnet, and the need to make quantitative comparisons with theory, mean that a full understanding of the role of magnetic barriers in controlling the critical current is necessary. This paper analyses the effect of magnetism and various magnetic configurations on Josephson critical currents; the overall treatment applies to junctions of general shape, but the specific cases of square and rectangular junctions are considered. (paper)

  18. Joint diseases: from connexins to gap junctions.

    Science.gov (United States)

    Donahue, Henry J; Qu, Roy W; Genetos, Damian C

    2017-12-19

    Connexons form the basis of hemichannels and gap junctions. They are composed of six tetraspan proteins called connexins. Connexons can function as individual hemichannels, releasing cytosolic factors (such as ATP) into the pericellular environment. Alternatively, two hemichannel connexons from neighbouring cells can come together to form gap junctions, membrane-spanning channels that facilitate cell-cell communication by enabling signalling molecules of approximately 1 kDa to pass from one cell to an adjacent cell. Connexins are expressed in joint tissues including bone, cartilage, skeletal muscle and the synovium. Indicative of their importance as gap junction components, connexins are also known as gap junction proteins, but individual connexin proteins are gaining recognition for their channel-independent roles, which include scaffolding and signalling functions. Considerable evidence indicates that connexons contribute to the function of bone and muscle, but less is known about the function of connexons in other joint tissues. However, the implication that connexins and gap junctional channels might be involved in joint disease, including age-related bone loss, osteoarthritis and rheumatoid arthritis, emphasizes the need for further research into these areas and highlights the therapeutic potential of connexins.

  19. Quantum Junction Solar Cells

    KAUST Repository

    Tang, Jiang; Liu, Huan; Zhitomirsky, David; Hoogland, Sjoerd; Wang, Xihua; Furukawa, Melissa; Levina, Larissa; Sargent, Edward H.

    2012-01-01

    -performing colloidal quantum dot rectifying devices reported to date have relied on a junction between a quantum-tuned absorber and a bulk material (e.g., TiO 2); however, quantum tuning of the absorber then requires complete redesign of the bulk acceptor, compromising

  20. Association of visceral adiposity with oesophageal and junctional adenocarcinomas.

    LENUS (Irish Health Repository)

    Beddy, P

    2012-02-01

    BACKGROUND: Obesity is associated with an increased incidence of oesophageal and oesophagogastric junction adenocarcinoma, in particular Siewert types I and II. This study compared abdominal fat composition in patients with oesophageal\\/junctional adenocarcinoma with that in patients with oesophageal squamous cell carcinoma and gastric adenocarcinoma, and in controls. METHOD: In total, 194 patients (110 with oesophageal\\/junctional adenocarcinoma, 38 with gastric adenocarcinoma and 46 with oesophageal squamous cell carcinoma) and 90 matched control subjects were recruited. The abdominal fat area was assessed using computed tomography (CT), and the total fat area (TFA), visceral fat area (VFA) and subcutaneous fat area (SFA) were calculated. RESULTS: Patients with oesophageal\\/junctional adenocarcinoma had significantly higher TFA and VFA values compared with controls (both P < 0.001), patients with gastric adenocarcinoma (P = 0.013 and P = 0.006 respectively) and patients with oesophageal squamous cell carcinoma (both P < 0.001). For junctional tumours, the highest TFA and VFA values were seen in patients with Siewert type I tumours (respectively P = 0.041 and P = 0.033 versus type III; P = 0.332 and P = 0.152 versus type II). CONCLUSION: Patients with oesophageal\\/junctional adenocarcinoma, in particular oesophageal and Siewert type I junctional tumours, have greater CT-defined visceral adiposity than patients with gastric adenocarcinoma or oesophageal squamous cell carcinoma, or controls.

  1. Visualizing supercurrents in 0-{pi} ferromagnetic Josephson tunnel junctions

    Energy Technology Data Exchange (ETDEWEB)

    Goldobin, Edward; Guerlich, Christian; Gaber, Tobias; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut and Center for Collective Quantum Phenomena, Universitaet Tuebingen (Germany); Weides, Martin; Kohlstedt, Hermann [Institute of Solid State Physics, Reserch Center Juelich (Germany)

    2009-07-01

    So-called 0 and {pi} Josephson junctions can be treated as having positive and negative critical currents. This implies that the same phase shift applied to a Josephson junction causes counterflow of supercurrents in 0 and in {pi} junctions connected in parallel provided they are short in comparison with Josephson penetration depth {lambda}{sub J}. We have fabricated several 0, {pi}, 0-{pi}, 0-{pi}-0 and 20 x (0-{pi}-) planar superconductor-insulator-ferromagnet-superconductor Josephson junctions and studied the spatial supercurrent density distribution j{sub s}(x,y) across the junction area using low temperature scanning electron microscopy. At zero magnetic field we clearly see counterflow of the supercurrents in 0 and {pi} regions. The picture also changes consistently in the applied magnetic field.

  2. Josephson junctions array resonators

    Energy Technology Data Exchange (ETDEWEB)

    Gargiulo, Oscar; Muppalla, Phani; Mirzaei, Iman; Kirchmair, Gerhard [Institute for Quantum Optics and Quantum Information, Innsbruck (Austria)

    2016-07-01

    We present an experimental analysis of the self- and cross-Kerr effect of extended plasma resonances in Josephson junction chains. The chain consists of 1600 individual junctions and we can measure quality factors in excess of 10000. The Kerr effect manifests itself as a frequency shift that depends linearly on the number of photons in a resonant mode. By changing the input power we are able to measure this frequency shift on a single mode (self-kerr). By changing the input power on another mode while measuring the same one, we are able to evaluate the cross-kerr effect. We can measure the cross-Kerr effect by probing the resonance frequency of one mode while exciting another mode of the array with a microwave drive.

  3. Curved Josephson junction

    International Nuclear Information System (INIS)

    Dobrowolski, Tomasz

    2012-01-01

    The constant curvature one and quasi-one dimensional Josephson junction is considered. On the base of Maxwell equations, the sine–Gordon equation that describes an influence of curvature on the kink motion was obtained. It is showed that the method of geometrical reduction of the sine–Gordon model from three to lower dimensional manifold leads to an identical form of the sine–Gordon equation. - Highlights: ► The research on dynamics of the phase in a curved Josephson junction is performed. ► The geometrical reduction is applied to the sine–Gordon model. ► The results of geometrical reduction and the fundamental research are compared.

  4. Contour junctions defined by dynamic image deformations enhance perceptual transparency.

    Science.gov (United States)

    Kawabe, Takahiro; Nishida, Shin'ya

    2017-11-01

    The majority of work on the perception of transparency has focused on static images with luminance-defined contour junctions, but recent work has shown that dynamic image sequences with dynamic image deformations also provide information about transparency. The present study demonstrates that when part of a static image is dynamically deformed, contour junctions at which deforming and nondeforming contours are connected facilitate the deformation-based perception of a transparent layer. We found that the impression of a transparent layer was stronger when a dynamically deforming area was adjacent to static nondeforming areas than when presented alone. When contour junctions were not formed at the dynamic-static boundaries, however, the impression of a transparent layer was not facilitated by the presence of static surrounding areas. The effect of the deformation-defined junctions was attenuated when the spatial pattern of luminance contrast at the junctions was inconsistent with the perceived transparency related to luminance contrast, while the effect did not change when the spatial luminance pattern was consistent with it. In addition, the results showed that contour completions across the junctions were required for the perception of a transparent layer. These results indicate that deformation-defined junctions that involve contour completion between deforming and nondeforming regions enhance the perception of a transparent layer, and that the deformation-based perceptual transparency can be promoted by the simultaneous presence of appropriately configured luminance and contrast-other features that can also by themselves produce the sensation of perceiving transparency.

  5. Flicker (1/f) noise in tunnel junction DC SQUIDS

    International Nuclear Information System (INIS)

    Koch, R.H.; Clarke, J.; Goubau, W.M.; Martinis, J.M.; Pegrum, C.M.; Van Harlingen, D.J.

    1983-01-01

    We have measured the spectral density of the 1/f voltage noise in current-biased resistively shunted Josephson tunnel junctions and dc SQUIDs. A theory in which fluctuations in the temperature give rise to fluctuations in the critical current and hence in the voltage predicts the magnitude of the noise quite accurately for junctions with areas of about 2 x 10 4 μm 2 , but significantly overestimates the noise for junctions with areas of about 6 μm 2 . DC SQUIDs fabricated from these two types of junctions exhibit substantially more 1/f voltage noise than would be predicted from a model in which the noise arises from critical current fluctuations in the junctions. This result was confirmed by an experiment involving two different bias current and flux modulation schemes, which demonstrated that the predominant 1/f voltage noise arises not from critical current fluctuations, but from some unknown source that can be regarded as an apparent 1/f flux noise. Measurements on five different configurations of dc SQUIDs fabricated with thin-film tunnel junctions and with widely varying areas, inductances, and junction capacitances show that the spectral density of the 1/f equivalent flux noise is roughtly constant, within a factor of three of (10 -10 /f)phi 2 0 Hz -1 . It is emphasized that 1/f flux noise may not be the predominant source of 1/f noise in SQUIDS fabricated with other technologies

  6. Macroscopic Refrigeration Using Superconducting Tunnel Junctions

    Science.gov (United States)

    Lowell, Peter; O'Neil, Galen; Underwood, Jason; Zhang, Xiaohang; Ullom, Joel

    2014-03-01

    Sub-kelvin temperatures are often a prerequisite for modern scientific experiments, such as quantum information processing, astrophysical missions looking for dark energy signatures and tabletop time resolved x-ray spectroscopy. Existing methods of reaching these temperatures, such as dilution refrigerators, are bulky and costly. In order to increase the accessibility of sub-Kelvin temperatures, we have developed a new method of refrigeration using normal-metal/insulator/superconductor (NIS) tunnel junctions. NIS junctions cool the electrons in the normal metal since the hottest electrons selectively tunnel from the normal metal into the superconductor. By extending the normal metal onto a thermally isolated membrane, the cold electrons can cool the phonons through the electron-phonon coupling. When these junctions are combined with a pumped 3He system, they provide a potentially inexpensive method of reaching these temperatures. Using only three devices, each with a junction area of approximately 3,500 μm2, we have cooled a 2 cm3 Cu plate from 290 mK to 256 mK. We will present these experimental results along with recent modeling predictions that strongly suggest that further refinements will allow cooling from 300 mK to 120 mK. This work is supported by the NASA APRA program.

  7. The human myotendinous junction

    DEFF Research Database (Denmark)

    Knudsen, A B; Larsen, M; Mackey, Abigail

    2015-01-01

    The myotendinous junction (MTJ) is a specialized structure in the musculotendinous system, where force is transmitted from muscle to tendon. Animal models have shown that the MTJ takes form of tendon finger-like processes merging with muscle tissue. The human MTJ is largely unknown and has never...... been described in three dimensions (3D). The aim of this study was to describe the ultrastructure of the human MTJ and render 3D reconstructions. Fourteen subjects (age 25 ± 3 years) with isolated injury of the anterior cruciate ligament (ACL), scheduled for reconstruction with a semitendinosus...

  8. Tight junctions and human diseases.

    Science.gov (United States)

    Sawada, Norimasa; Murata, Masaki; Kikuchi, Keisuke; Osanai, Makoto; Tobioka, Hirotoshi; Kojima, Takashi; Chiba, Hideki

    2003-09-01

    Tight junctions are intercellular junctions adjacent to the apical end of the lateral membrane surface. They have two functions, the barrier (or gate) function and the fence function. The barrier function of tight junctions regulates the passage of ions, water, and various macromolecules, even of cancer cells, through paracellular spaces. The barrier function is thus relevant to edema, jaundice, diarrhea, and blood-borne metastasis. On the other hand, the fence function maintains cell polarity. In other words, tight junctions work as a fence to prevent intermixing of molecules in the apical membrane with those in the lateral membrane. This function is deeply involved in cancer cell biology, in terms of loss of cell polarity. Of the proteins comprising tight junctions, integral membrane proteins occludin, claudins, and JAMs have been recently discovered. Of these molecules, claudins are exclusively responsible for the formation of tight-junction strands and are connected with the actin cytoskeleton mediated by ZO-1. Thus, both functions of tight junctions are dependent on the integrity of the actin cytoskeleton as well as ATP. Mutations in the claudin14 and the claudin16 genes result in hereditary deafness and hereditary hypomagnesemia, respectively. Some pathogenic bacteria and viruses target and affect the tight-junction function, leading to diseases. In this review, the relationship between tight junctions and human diseases is summarized.

  9. Gap junctions and motor behavior

    DEFF Research Database (Denmark)

    Kiehn, Ole; Tresch, Matthew C.

    2002-01-01

    The production of any motor behavior requires coordinated activity in motor neurons and premotor networks. In vertebrates, this coordination is often assumed to take place through chemical synapses. Here we review recent data suggesting that electrical gap-junction coupling plays an important role...... in coordinating and generating motor outputs in embryonic and early postnatal life. Considering the recent demonstration of a prevalent expression of gap-junction proteins and gap-junction structures in the adult mammalian spinal cord, we suggest that neuronal gap-junction coupling might also contribute...... to the production of motor behavior in adult mammals....

  10. Diversification dynamics and transoceanic Eurasian-Australian disjunction in the genus Picris (Compositae) induced by the interplay of shifts in intrinsic/extrinsic traits and paleoclimatic oscillations.

    Science.gov (United States)

    Slovák, Marek; Kučera, Jaromír; Lack, Hans Walter; Ziffer-Berger, Jotham; Melicharková, Andrea; Záveská, Eliška; Vďačný, Peter

    2018-02-01

    Understanding transcontinental biogeographic patterns has been one of the main foci of the field of biogeography. While multiple explanations for transcontinental disjunctions have been proposed, little is still known about the relative importance of intrinsic and extrinsic traits for the diversification dynamics of disjunct taxa. Here, we study the evolutionary history of the genus Picris L. (Compositae), a great model for investigating the diversification dynamics of transoceanic bipolar disjunct organisms. Ancestral state reconstructions indicate that the most recent common ancestor (MRCA) of Picris was a semelparous and heterocarpic herb that lived in unpredictable environments of North Africa and West Asia. Diversification analyses suggest a significant shift in speciation ca. 1 million years ago, likely associated with the onset of the mid-Pleistocene revolution. Longevity characters are correlated with the evolution of particular fruit types and with environmental conditions. Heterocarpic species are mostly semelparous herbs strongly linked with unpredictable habitats, while homocarpic taxa are mostly iteroparous plants occurring in predictable environments. Binary-state speciation and extinction analyses suggest that homocarpy, iteroparity, and habitats predictability accelerate diversification. Although the combination of homocarpy and iteroparity evolved in several lineages, only members of the P. hieracioides group were able to colonise Eurasia and expand to Australia by transoceanic dispersal. Those findings indicate that large-scale colonisation events depend on a complex interplay of intrinsic and extrinsic factors. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Junction detection and pathway selection

    Science.gov (United States)

    Peck, Alex N.; Lim, Willie Y.; Breul, Harry T.

    1992-02-01

    The ability to detect junctions and make choices among the possible pathways is important for autonomous navigation. In our script-based navigation approach where a journey is specified as a script of high-level instructions, actions are frequently referenced to junctions, e.g., `turn left at the intersection.' In order for the robot to carry out these kind of instructions, it must be able (1) to detect an intersection (i.e., an intersection of pathways), (2) know that there are several possible pathways it can take, and (3) pick the pathway consistent with the high level instruction. In this paper we describe our implementation of the ability to detect junctions in an indoor environment, such as corners, T-junctions and intersections, using sonar. Our approach uses a combination of partial scan of the local environment and recognition of sonar signatures of certain features of the junctions. In the case where the environment is known, we use additional sensor information (such as compass bearings) to help recognize the specific junction. In general, once a junction is detected and its type known, the number of possible pathways can be deduced and the correct pathway selected. Then the appropriate behavior for negotiating the junction is activated.

  12. Mixing in T-junctions

    NARCIS (Netherlands)

    Kok, Jacobus B.W.; van der Wal, S.

    1996-01-01

    The transport processes that are involved in the mixing of two gases in a T-junction mixer are investigated. The turbulent flow field is calculated for the T-junction with the k- turbulence model by FLOW3D. In the mathematical model the transport of species is described with a mixture fraction

  13. Dynamics of Josephson junction arrays

    International Nuclear Information System (INIS)

    Hadley, P.

    1989-01-01

    The dynamics of Josephson junction arrays is a topic that lies at the intersection of the fields of nonlinear dynamics and Josephson junction technology. The series arrays considered here consist of several rapidly oscillating Josephson junctions where each junction is coupled equally to every other junction. The purpose of this study is to understand phaselocking and other cooperative dynamics of this system. Previously, little was known about high dimensional nonlinear systems of this sort. Numerical simulations are used to study the dynamics of these arrays. Three distinct types of periodic solutions to the array equations were observed as well as period doubled and chaotic solutions. One of the periodic solutions is the symmetric, in-phase solution where all of the junctions oscillate identically. The other two periodic solutions are symmetry-broken solutions where all of the junction do not oscillate identically. The symmetry-broken solutions are highly degenerate. As many as (N - 1) stable solutions can coexist for an array of N junctions. Understanding the stability of these several solutions and the transitions among them is vital to the design of useful devices

  14. Molecular electronics: some views on transport junctions and beyond.

    Science.gov (United States)

    Joachim, Christian; Ratner, Mark A

    2005-06-21

    The field of molecular electronics comprises a fundamental set of issues concerning the electronic response of molecules as parts of a mesoscopic structure and a technology-facing area of science. We will overview some important aspects of these subfields. The most advanced ideas in the field involve the use of molecules as individual logic or memory units and are broadly based on using the quantum state space of the molecule. Current work in molecular electronics usually addresses molecular junction transport, where the molecule acts as a barrier for incoming electrons: This is the fundamental Landauer idea of "conduction as scattering" generalized to molecular junction structures. Another point of view in terms of superexchange as a guiding mechanism for coherent electron transfer through the molecular bridge is discussed. Molecules generally exhibit relatively strong vibronic coupling. The last section of this overview focuses on vibronic effects, including inelastic electron tunneling spectroscopy, hysteresis in junction charge transport, and negative differential resistance in molecular transport junctions.

  15. Probing electrical transport in individual carbon nanotubes and junctions

    International Nuclear Information System (INIS)

    Kim, Tae-Hwan; Wendelken, John F; Li Anping; Du Gaohui; Li Wenzhi

    2008-01-01

    The electrical transport properties of individual carbon nanotubes (CNTs) and multi-terminal junctions of CNTs are investigated with a quadraprobe scanning tunneling microscope. The CNTs used in this study are made of stacked herringbone-type conical graphite sheets with a cone angle of ∼20 deg. to the tube axis, and the CNT junctions have no catalytic particles in the junction areas. The CNTs have a significantly higher resistivity than conventional CNTs with concentric walls. The straight CNTs display linear current-voltage (I-V) characteristics, indicating diffusive transport rather than ballistic transport. The structural deformation in CNTs with bends substantially increases the resistivity in comparison with that for the straight segments on the same CNTs, and the I-V curve departs slightly from linearity in curved segments. The junction area of the CNT junctions behaves like an ohmic-type scattering center with linear I-V characteristics. In addition, a gating effect has not been observed, in contrast to the case for conventional multi-walled CNT junctions. These unusual transport properties can be attributed to the enhanced inter-layer interaction in the herringbone-type CNTs.

  16. Pattern of cross-sensitivity between 4 Compositae plants, Parthenium hysterophorus, Xanthium strumarium, Helianthus annuus and Chrysanthemum coronarium, in Indian patients.

    Science.gov (United States)

    Nandakishore, T; Pasricha, J S

    1994-03-01

    To assess the pattern of cross-sensitivity between 4 members of the Compositae family, namely Parthenium hysterophorus L., Xanthium strumarium L., Helanthus annuus L. and Chrysanthemum coronarium L., 63 patients clinically diagnosed to have airborne contact dermatitis, and 51 controls having well-defined patterns of contact dermatitis caused by agents other than plants, were patch tested with measured amounts of standardized aqueous extracts of these plants. Positive reactions were obtained in 62 patients and 13 controls with Parthenium hysterophorus, in 47 patients and 9 controls with Xanthium strumarium, in 7 patients and 2 controls with Helianthus annuus, and in 13 of the 57 patients and one out of 28 controls tested with Chrysanthemum coronarium. 2 patients were allergic to all 4 of the plants; 14 patients to 3 plants, namely Parthenium, Xanthium and Chrysanthemum in 9 cases and Parthenium, Xanthium and Helianthus in 5 cases; 32 patients to 2 plants, namely Parthenium and Xanthium in 30 cases, and Parthenium and Chrysanthemum, and Xanthium and Chrysanthemum in 1 case each; 15 patients were allergic to 1 plant only, that being Parthenium. All the 47 patients allergic to Xanthium, 13 patients allergic to Chrysanthemum and 7 patients allergic to Helianthus were positive with some other plant as well. There was 1 patient who was allergic to Xanthium and Chrysanthemum but not to Parthenium. The titre of contact hypersensitivity (TCH) determined in the patients allergic to Parthenium, Xanthium and Helianthus showed values that varied widely with each plant in different patients, and there was no parallelism between the TCH with various plants.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Is the extremely rare Iberian endemic plant species Castrilanthemum debeauxii (Compositae, Anthemideae) a 'living fossil'? Evidence from a multi-locus species tree reconstruction.

    Science.gov (United States)

    Tomasello, Salvatore; Álvarez, Inés; Vargas, Pablo; Oberprieler, Christoph

    2015-01-01

    The present study provides results of multi-species coalescent species tree analyses of DNA sequences sampled from multiple nuclear and plastid regions to infer the phylogenetic relationships among the members of the subtribe Leucanthemopsidinae (Compositae, Anthemideae), to which besides the annual Castrilanthemum debeauxii (Degen, Hervier & É.Rev.) Vogt & Oberp., one of the rarest flowering plant species of the Iberian Peninsula, two other unispecific genera (Hymenostemma, Prolongoa), and the polyploidy complex of the genus Leucanthemopsis belong. Based on sequence information from two single- to low-copy nuclear regions (C16, D35, characterised by Chapman et al. (2007)), the multi-copy region of the nrDNA internal transcribed spacer regions ITS1 and ITS2, and two intergenic spacer regions of the cpDNA gene trees were reconstructed using Bayesian inference methods. For the reconstruction of a multi-locus species tree we applied three different methods: (a) analysis of concatenated sequences using Bayesian inference (MrBayes), (b) a tree reconciliation approach by minimizing the number of deep coalescences (PhyloNet), and (c) a coalescent-based species-tree method in a Bayesian framework ((∗)BEAST). All three species tree reconstruction methods unequivocally support the close relationship of the subtribe with the hitherto unclassified genus Phalacrocarpum, the sister-group relationship of Castrilanthemum with the three remaining genera of the subtribe, and the further sister-group relationship of the clade of Hymenostemma+Prolongoa with a monophyletic genus Leucanthemopsis. Dating of the (∗)BEAST phylogeny supports the long-lasting (Early Miocene, 15-22Ma) taxonomical independence and the switch from the plesiomorphic perennial to the apomorphic annual life-form assumed for the Castrilanthemum lineage that may have occurred not earlier than in the Pliocene (3Ma) when the establishment of a Mediterranean climate with summer droughts triggered evolution towards

  18. Instabilities in thin tunnel junctions

    International Nuclear Information System (INIS)

    Konkin, M.K.; Adler, J.G.

    1978-01-01

    Tunnel junctions prepared for inelastic electron tunneling spectroscopy are often plagued by instabilities in the 0-500-meV range. This paper relates the bias at which the instability occurs to the barrier thickness

  19. The Control of Junction Flows

    National Research Council Canada - National Science Library

    Smith, Charles

    1997-01-01

    An experimental study of the effects of spatially-limited (i.e. localized) surface suction on unsteady laminar and turbulent junction flows was performed using hydrogen bubble flow visualization and Particle Image Velocimetry (PIV...

  20. Electronic thermometry in tunable tunnel junction

    Science.gov (United States)

    Maksymovych, Petro

    2016-03-15

    A tunable tunnel junction thermometry circuit includes a variable width tunnel junction between a test object and a probe. The junction width is varied and a change in thermovoltage across the junction with respect to the change in distance across the junction is determined. Also, a change in biased current with respect to a change in distance across the junction is determined. A temperature gradient across the junction is determined based on a mathematical relationship between the temperature gradient, the change in thermovoltage with respect to distance and the change in biased current with respect to distance. Thermovoltage may be measured by nullifying a thermoelectric tunneling current with an applied voltage supply level. A piezoelectric actuator may modulate the probe, and thus the junction width, to vary thermovoltage and biased current across the junction. Lock-in amplifiers measure the derivatives of the thermovoltage and biased current modulated by varying junction width.

  1. Peltier cooling in molecular junctions

    Science.gov (United States)

    Cui, Longji; Miao, Ruijiao; Wang, Kun; Thompson, Dakotah; Zotti, Linda Angela; Cuevas, Juan Carlos; Meyhofer, Edgar; Reddy, Pramod

    2018-02-01

    The study of thermoelectricity in molecular junctions is of fundamental interest for the development of various technologies including cooling (refrigeration) and heat-to-electricity conversion1-4. Recent experimental progress in probing the thermopower (Seebeck effect) of molecular junctions5-9 has enabled studies of the relationship between thermoelectricity and molecular structure10,11. However, observations of Peltier cooling in molecular junctions—a critical step for establishing molecular-based refrigeration—have remained inaccessible. Here, we report direct experimental observations of Peltier cooling in molecular junctions. By integrating conducting-probe atomic force microscopy12,13 with custom-fabricated picowatt-resolution calorimetric microdevices, we created an experimental platform that enables the unified characterization of electrical, thermoelectric and energy dissipation characteristics of molecular junctions. Using this platform, we studied gold junctions with prototypical molecules (Au-biphenyl-4,4'-dithiol-Au, Au-terphenyl-4,4''-dithiol-Au and Au-4,4'-bipyridine-Au) and revealed the relationship between heating or cooling and charge transmission characteristics. Our experimental conclusions are supported by self-energy-corrected density functional theory calculations. We expect these advances to stimulate studies of both thermal and thermoelectric transport in molecular junctions where the possibility of extraordinarily efficient energy conversion has been theoretically predicted2-4,14.

  2. Re-evaluation of the Helichrysum italicum complex (Compositae: Gnaphalieae: A new species from Majorca (Balearic Islands

    Directory of Open Access Journals (Sweden)

    S. Herrando-Moraira

    2016-09-01

    Full Text Available Helichrysum italicum is a widely distributed species in the Mediterranean Basin, which has received controversial taxonomic treatments at infraspecific level owing to its morphological variability. In this paper we perform a detailed multivariate analysis of morphological characters using an exhaustive sampling of H. italicum. Integrating previously published molecular, chorological and newly obtained morphological data, a revised taxonomic treatment for the whole H. italicum complex is provided. On the one hand, the results obtained suggest that the Majorcan mountain populations of H. italicum subsp. microphyllum need to be considered an independent species, newly described here as Helichrysum massanellanum. On the other hand, H. italicum subspecies are recircumscribed. A new combination is proposed, H. italicum subsp. tyrrhenicum, a taxon that comprises populations from Corsica, Sardinia, Majorca coastline and Dragonera islet, whereas subsp. microphyllum is restricted to the island of Crete. With those substantial classification modifications, a complete new taxonomic treatment is presented for this group, including an identification key, synonyms, morphological descriptions, distribution areas and habitat characterization.

  3. Operating modes of superconducting tunnel junction device

    Energy Technology Data Exchange (ETDEWEB)

    Maehata, Keisuke [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering

    1998-07-01

    In the Electrotechnical Laboratory, an Nb type superconducting tunnel junction (STJ) device with 200 x 200 sq. micron in area and super high quality was manufactured. By using 55-fe source, response of this large area STJ to X-ray was measured. In this measurement, two action modes with different output wave height from front amplifier were observed. Then, in this study, current-voltage feature of the element in each action mode was analyzed to elucidate a mechanism to form such two action modes. The feature was analyzed by using first order approximate solution on cavity resonance mode of Sine-Gordon equation. From the analytical results, it could be supposed that direction and magnitude of effective magnetic field penetrating into jointed area changed by an induction current effect owing to impressing speed of the magnetic field, which brings two different current-voltage features to make possible to observe two action modes with different pulse wave height. (G.K.)

  4. Transport properties of molecular junctions

    CERN Document Server

    Zimbovskaya, Natalya A

    2013-01-01

    A comprehensive overview of the physical mechanisms that control electron transport and the characteristics of metal-molecule-metal (MMM) junctions is presented. As far as possible, methods and formalisms presented elsewhere to analyze electron transport through molecules are avoided. This title introduces basic concepts—a description of the electron transport through molecular junctions—and briefly describes relevant experimental methods. Theoretical methods commonly used to analyze the electron transport through molecules are presented. Various effects that manifest in the electron transport through MMMs, as well as the basics of density-functional theory and its applications to electronic structure calculations in molecules are presented. Nanoelectronic applications of molecular junctions and similar systems are discussed as well. Molecular electronics is a diverse and rapidly growing field. Transport Properties of Molecular Junctions presents an up-to-date survey of the field suitable for researchers ...

  5. NbN tunnel junctions

    International Nuclear Information System (INIS)

    Villegier, J.C.; Vieux-Rochaz, L.; Goniche, M.; Renard, P.; Vabre, M.

    1984-09-01

    All-niobium nitride Josephon junctions have been prepared successfully using a new processing called SNOP: Selective Niobium (nitride) Overlap Process. Such a process involves the ''trilayer'' deposition on the whole wafer before selective patterning of the electrodes by optically controlled dry reactive ion etching. Only two photomask levels are need to define an ''overlap'' or a ''cross-type'' junction with a good accuracy. The properties of the niobium nitride films deposited by DC-magnetron sputtering and the surface oxide growth are analysed. The most critical point to obtain high quality and high gap value junctions resides in the early stage of the NbN counterelectrode growth. Some possibilities to overcome such a handicap exist even if the fabrication needs substrate temperatures below 250 0 C

  6. Gravitation at the Josephson Junction

    Directory of Open Access Journals (Sweden)

    Victor Atanasov

    2018-01-01

    Full Text Available A geometric potential from the kinetic term of a constrained to a curved hyperplane of space-time quantum superconducting condensate is derived. An energy conservation relation involving the geometric field at every material point in the superconductor is demonstrated. At a Josephson junction the energy conservation relation implies the possibility of transforming electric energy into geometric field energy, that is, curvature of space-time. Experimental procedures to verify that the Josephson junction can act as a voltage-to-curvature converter are discussed.

  7. Chlorpromazine reduces the intercellular communication via gap junctions in mammalian cells

    International Nuclear Information System (INIS)

    Orellana, Juan A.; Palacios-Prado, Nicolas; Saez, Juan C.

    2006-01-01

    In the work presented herein, we evaluated the effect of chlorpromazine (CPZ) on gap junctions expressed by two mammalian cell types; Gn-11 cells (cell line derived from mouse LHRH neurons) and rat cortical astrocytes maintained in culture. We also attempted to elucidate possible mechanisms of action of CPZ effects on gap junctions. CPZ, in concentrations comparable with doses used to treat human diseases, was found to reduce the intercellular communication via gap junctions as evaluated with measurements of dye coupling (Lucifer yellow). In both cell types, maximal inhibition of functional gap junctions was reached within about 1 h of treatment with CPZ, an recovery was almost complete at about 5 h after CPZ wash out. In both cell types, CPZ treatment increased the phosphorylation state of connexin43 (Cx43), a gap junction protein subunit. Moreover, CPZ reduced the reactivity of Cx43 (immunofluorescence) at cell interfaces and concomitantly increased its reactivity in intracellular vesicles, suggesting an increased retrieval from and/or reduced insertion into the plasma membrane. CPZ also caused cellular retraction reducing cell-cell contacts in a reversible manner. The reduction in contact area might destabilize existing gap junctions and abrogate formation of new ones. Moreover, the CPZ-induced reduction in gap junctional communication may depend on the connexins (Cxs) forming the junctions. If Cx43 were the only connexin expressed, MAPK-dependent phosphorylation of this connexin would induce closure of gap junction channels

  8. Electronic noise of superconducting tunnel junction detectors

    International Nuclear Information System (INIS)

    Jochum, J.; Kraus, H.; Gutsche, M.; Kemmather, B.; Feilitzsch, F. v.; Moessbauer, R.L.

    1994-01-01

    The optimal signal to noise ratio for detectors based on superconducting tunnel junctions is calculated and compared for the cases of a detector consisting of one single tunnel junction, as well as of series and of parallel connections of such tunnel junctions. The influence of 1 / f noise and its dependence on the dynamical resistance of tunnel junctions is discussed quantitatively. A single tunnel junction yields the minimum equivalent noise charge. Such a tunnel junction exhibits the best signal to noise ratio if the signal charge is independent of detector size. In case, signal charge increases with detector size, a parallel or a series connection of tunnel junctions would provide the optimum signal to noise ratio. The equivalent noise charge and the respective signal to noise ratio are deduced as functions of tunnel junction parameters such as tunneling time, quasiparticle lifetime, etc. (orig.)

  9. Photovoltaic Cells Improvised With Used Bipolar Junction Transistors

    International Nuclear Information System (INIS)

    Akintayo, J. A

    2002-01-01

    The understanding of the underlying principle that the solar cell consists of a p-n junction is exploited to adapt the basic NPN or PNP Bipolar Junction Transistors (BJT) to serve as solar cells. In this mode the in improvised solar cell have employed just the emitter and the base sections with an intact emitter/base junction as the active PN area. The improvised devices tested screened and sorted are wired up in strings, blocks and modules. The photovoltaic modules realised tested as close replica of solar cells with output voltage following insolation level. Further work need be done on the modules to make them generate usable levels of output voltage and current

  10. Thin film hybrid Josephson junctions with Co doped Ba-122

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Stefan; Doering, Sebastian; Schmidl, Frank; Tympel, Volker; Grosse, Veit; Seidel, Paul [Friedrich-Schiller-Universitaet Jena, Institut fuer Festkoerperphysik, Helmholtzweg 5, 07743 Jena (Germany); Haindl, Silvia; Iida, Kazumasa; Kurth, Fritz; Holzapfel, Bernhard [IFW Dresden, Institut fuer Metallische Werkstoffe, Helmholtzstrasse 20, 01069 Dresden (Germany); Moench, Ingolf [IFW Dresden, Institut fuer Integrative Nanowissenschaften, Helmholtzstrasse 20, 01069 Dresden (Germany)

    2011-07-01

    Josephson junctions are a strong tool to investigate fundamental superconducting properties, such as gap behaviour, dependencies from external fields and the order parameter symmetry. Finding secure values enables the possibility of theoretical descriptions to understand the physical processes within the new iron-based superconductors. Based on Co-doped BaFe{sub 2}As{sub 2} (Ba-122) layers produced via pulsed laser deposition (PLD) on (La,Sr)(Al,Ta)O{sub 3} substrates, we manufactured superconductor-normal conductor-superconductor (S-N-S) junctions structures by using photolithography, ion beam etching as well as insulating SiO{sub 2} layers. We present working Ba-122/Au/PbIn thin film Josephson junctions with different contact areas and barrier thicknesses, their temperature dependence and response to microwave irradiation. The calculated I{sub c}R{sub N} product is in the range of a couple of microvolts.

  11. Magnetic properties of slablike Josephson-junction arrays

    International Nuclear Information System (INIS)

    Chen, D.; Sanchez, A.; Hernando, A.

    1994-01-01

    Magnetic properties of infinitely long and wide slablike Josephson-junction arrays (JJA's) consisting of 2N+1 rows of grains are calculated for the dc Josephson effect with gauge-invariant phase differences. When N is large, the intergranular magnetization curve, M J (H), of the JJA's in low fields approaches that of uniform Josephson junctions with lengths equal to the thicknesses of the JJA's, but in a larger field interval, its amplitude is dually modulated with periods determined by the junction and void areas. M J (H) curves for small N are more complicated. The concept of Josephson vortices and the application of the results to high-T c superconductors are discussed

  12. Current noise in tunnel junctions

    Energy Technology Data Exchange (ETDEWEB)

    Frey, Moritz; Grabert, Hermann [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Strasse 3, 79104, Freiburg (Germany)

    2017-06-15

    We study current fluctuations in tunnel junctions driven by a voltage source. The voltage is applied to the tunneling element via an impedance providing an electromagnetic environment of the junction. We use circuit theory to relate the fluctuations of the current flowing in the leads of the junction with the voltage fluctuations generated by the environmental impedance and the fluctuations of the tunneling current. The spectrum of current fluctuations is found to consist of three parts: a term arising from the environmental Johnson-Nyquist noise, a term due to the shot noise of the tunneling current and a third term describing the cross-correlation between these two noise sources. Our phenomenological theory reproduces previous results based on the Hamiltonian model for the dynamical Coulomb blockade and provides a simple understanding of the current fluctuation spectrum in terms of circuit theory and properties of the average current. Specific results are given for a tunnel junction driven through a resonator. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Dynamics of pi-junction interferometer circuits

    DEFF Research Database (Denmark)

    Kornkev, V.K.; Mozhaev, P.B.; Borisenko, I.V.

    2002-01-01

    The pi-junction superconducting circuit dynamics was studied by means of numerical simulation technique. Parallel arrays consisting of Josephson junctions of both 0- and pi-type were studied as a model of high-T-c grain-boundary Josephson junction. The array dynamics and the critical current depe...

  14. Compositae dermatitis from airborne parthenolide

    DEFF Research Database (Denmark)

    Paulsen, E.; Christensen, Lars Porskjær; Andersen, K.E.

    2007-01-01

    of the HIVAS extract by gas chromatography and mass spectrometry detected PHL in a concentration of 510 ng mL(-1) in the HIVAS extract. Testing with a dilution series of PHL showed positive reactions down to 8.1 ng in selected patients. None of the 12 patients tested positive to monoterpenes or sesquiterpenes......, obtained by fractionation of ether extracts, dynamic headspace and high-volume air sampler (HIVAS) technique, respectively. RESULTS: Among 12 feverfew-allergic patients, eight had positive patch-test reactions to a HIVAS filter extract, while two tested positive to a headspace extract. Subsequent analysis...

  15. Charge Transport Processes in Molecular Junctions

    Science.gov (United States)

    Smith, Christopher Eugene

    Molecular electronics (ME) has evolved into a rich area of exploration that combines the fields of chemistry, materials, electronic engineering and computational modeling to explore the physics behind electronic conduction at the molecular level. Through studying charge transport properties of single molecules and nanoscale molecular materials the field has gained the potential to bring about new avenues for the miniaturization of electrical components where quantum phenomena are utilized to achieve solid state molecular device functionality. Molecular junctions are platforms that enable these studies and consist of a single molecule or a small group of molecules directly connected to electrodes. The work presented in this thesis has built upon the current understanding of the mechanisms of charge transport in ordered junctions using self-assembled monolayer (SAM) molecular thin films. Donor and acceptor compounds were synthesized and incorporated into SAMs grown on metal substrates then the transport properties were measured with conducting probe atomic force microscopy (CP-AFM). In addition to experimentally measured current-voltage (I-V) curves, the transport properties were addressed computationally and modeled theoretically. The key objectives of this project were to 1) investigate the impact of molecular structure on hole and electron charge transport, 2) understand the nature of the charge carriers and their structure-transport properties through long (chemically gated to modulate the transport. These results help advance our understanding of transport behavior in semiconducting molecular thin films, and open opportunities to engineer improved electronic functionality into molecular devices.

  16. Ferromagnetic Josephson Junctions for Cryogenic Memory

    Science.gov (United States)

    Niedzielski, Bethany M.; Gingrich, Eric C.; Khasawneh, Mazin A.; Loloee, Reza; Pratt, William P., Jr.; Birge, Norman O.

    2015-03-01

    Josephson junctions containing ferromagnetic materials are of interest for both scientific and technological purposes. In principle, either the amplitude of the critical current or superconducting phase shift across the junction can be controlled by the relative magnetization directions of the ferromagnetic layers in the junction. Our approach concentrates on phase control utilizing two junctions in a SQUID geometry. We will report on efforts to control the phase of junctions carrying either spin-singlet or spin-triplet supercurrent for cryogenic memory applications. Supported by Northorp Grumman Corporation and by IARPA under SPAWAR Contract N66001-12-C-2017.

  17. Radiation detection with Nb/Al-AlOx/Al/Nb superconducting tunnel junctions

    International Nuclear Information System (INIS)

    Matsumura, Atsuki; Takahashi, Toru; Kurakado, Masahiko

    1992-01-01

    Superconductor radiation detectors have the possibility of 20-30 times better energy resolution than that of a high resolution Si detector. We fabricated Nb/Al-AlOx/Al/Nb superconducting tunnel junctions with low leakage current. X rays were detected with large area junctions of 178x178 μm 2 . High energy resolution of 160 eV for 5.9 keV was obtained. We also fabricated series connected junctions which covers a rather large area of 4x4 mm 2 . α particles injected into the rear substrate were detected using nonthermal phonons induced by the radiations in the substrate. (author)

  18. Molecular series-tunneling junctions.

    Science.gov (United States)

    Liao, Kung-Ching; Hsu, Liang-Yan; Bowers, Carleen M; Rabitz, Herschel; Whitesides, George M

    2015-05-13

    Charge transport through junctions consisting of insulating molecular units is a quantum phenomenon that cannot be described adequately by classical circuit laws. This paper explores tunneling current densities in self-assembled monolayer (SAM)-based junctions with the structure Ag(TS)/O2C-R1-R2-H//Ga2O3/EGaIn, where Ag(TS) is template-stripped silver and EGaIn is the eutectic alloy of gallium and indium; R1 and R2 refer to two classes of insulating molecular units-(CH2)n and (C6H4)m-that are connected in series and have different tunneling decay constants in the Simmons equation. These junctions can be analyzed as a form of series-tunneling junctions based on the observation that permuting the order of R1 and R2 in the junction does not alter the overall rate of charge transport. By using the Ag/O2C interface, this system decouples the highest occupied molecular orbital (HOMO, which is localized on the carboxylate group) from strong interactions with the R1 and R2 units. The differences in rates of tunneling are thus determined by the electronic structure of the groups R1 and R2; these differences are not influenced by the order of R1 and R2 in the SAM. In an electrical potential model that rationalizes this observation, R1 and R2 contribute independently to the height of the barrier. This model explicitly assumes that contributions to rates of tunneling from the Ag(TS)/O2C and H//Ga2O3 interfaces are constant across the series examined. The current density of these series-tunneling junctions can be described by J(V) = J0(V) exp(-β1d1 - β2d2), where J(V) is the current density (A/cm(2)) at applied voltage V and βi and di are the parameters describing the attenuation of the tunneling current through a rectangular tunneling barrier, with width d and a height related to the attenuation factor β.

  19. Composita wewnątrzwspólnotowe – wyrazy złożone z cząstką евро- w języku bułgarskim

    Directory of Open Access Journals (Sweden)

    Natalia Długosz

    2015-08-01

    Full Text Available Intracommunitary compositas – compounds with евро- particle in Bulgarian From the observation of a contemporary Bulgarian word formation system results that the number of compounds which significant part is developed basing on new productive models is constantly increasing. Therefore the subject of this article constitute Bulgarian compounds with a disintegrated particle евро- that are thematically connected with the process of European Integration. I begin the analysis from the description of compositas’ word formation construction. Then I go to semantic dissertation (I make an attempt to classify all mentioned structures thematically and I create a dictionary definition of the евро- particle and on to stylistic ones (I pay special attention to the functioning of the discussed units both in a text, and in a lexical system.

  20. Flexible 2D layered material junctions

    Science.gov (United States)

    Balabai, R.; Solomenko, A.

    2018-03-01

    Within the framework of the methods of the electron density functional and the ab initio pseudopotential, we have obtained the valence electron density spatial distribution, the densities of electron states, the widths of band gaps, the charges on combined regions, and the Coulomb potentials for graphene-based flexible 2D layered junctions, using author program complex. It is determined that the bending of the 2D layered junctions on the angle α leads to changes in the electronic properties of these junctions. In the graphene/graphane junction, there is clear charge redistribution with different signs in the regions of junctions. The presence in the heterojunctions of charge regions with different signs leads to the formation of potential barriers. The greatest potential jump is in the graphene/fluorographene junction. The greatest value of the band gap width is in the graphene/graphane junction.

  1. Fabrication of sub-micron whole waffer SIS tunnel junctions for millimeter wave mixers

    International Nuclear Information System (INIS)

    Huq, S.E.; Blamire, M.G.; Evetts, J.E.; Hasko, D.G.; Ahmed, H.

    1991-01-01

    As a part of a programme for the development of a space-qualified sub-mm-wave mixer operating in the region of one terahertz we have been developing the processes required for the fabrication of submicron whole wafer tunnel junctions. Using the self-aligned whole-wafer process (SAWW) with electron beam lithography we have been able to reliably fabricate high quality (V m > 20 mV) submicron tunnel junctions from whole wafer Nb/AlO x /Nb structures. In particular we show that the junction quality is independent of size down to 0.3 μm 2 junction area. The problems of film stress, anodization, registration for electron beam lithography and lift-off, which limit the yield of good quality sub-micron scale junctions are addressed in this paper

  2. Macroscopic quantum effects in the zero voltage state of the current biased Josephson junction

    International Nuclear Information System (INIS)

    Clarke, J.; Devoret, M.H.; Martinis, J.; Esteve, D.

    1985-05-01

    When a weak microwave current is applied to a current-biased Josephson tunnel junction in the thermal limit the escape rate from the zero voltage state is enhanced when the microwave frequency is near the plasma frequency of the junction. The resonance curve is markedly asymmetric because of the anharmonic properties of the potential well: this behavior is well explained by a computer simulation using a resistively shunted junction model. This phenomenon of resonant activation enables one to make in situ measurements of the capacitance and resistance shunting the junction, including contributions from the complex impedance presented by the current leads. For the relatively large area junctions studied in these experiments, the external capacitive loading was relatively unimportant, but the damping was entirely dominated by the external resistance

  3. R.f.-induced steps in mutually coupled, two-dimensional distributed Josephson tunnel junctions

    International Nuclear Information System (INIS)

    Klein, U.; Dammschneider, P.

    1991-01-01

    This paper reports on the amplitudes of the current steps in the I-V characteristics of mutually coupled two-dimensional distributed Josephson tunnel junctions driven by microwaves. For this purpose we use a numerical computation algorithm based on a planar resonator model for the individual Josephson tunnel junctions to calculate the d.c. current density distribution. In addition to the fundamental microwave frequency, harmonic contents of the tunneling current are also considered. The lateral dimensions of the individual junctions are small compared to the microwave wavelength and the Josephson penetration depth, giving an almost constant current density distribution. Therefore, the coupled junctions can give much greater step amplitudes than a single junction with an equal tunneling area, because of their nonuniform current density distribution

  4. Josephson junctions and circle maps

    Energy Technology Data Exchange (ETDEWEB)

    Bak, P; Bohr, T; Jensen, M H; Christiansen, P V

    1984-01-01

    The return map of a differential equation for the current driven Josephson junction, or the damped driven pendulum, is shown numerically to be a circle map. Phase locking, noise and hysteresis, can thus be understood in a simple and coherent way. The transition to chaos is related to the development of a cubic inflection point. Recent theoretical results on universal behavior at the transition to chaos can readily be checked experimentally by studying I-V characteristics. 17 references, 1 figure.

  5. Squeezed States in Josephson Junctions.

    Science.gov (United States)

    Hu, X.; Nori, F.

    1996-03-01

    We have studied quantum fluctuation properties of Josephson junctions in the limit of large Josephson coupling energy and small charging energy, when the eigenstates of the system can be treated as being nearly localized. We have considered(X. Hu and F. Nori, preprints.) a Josephson junction in a variety of situations, e.g., coupled to one or several of the following elements: a capacitor, an inductor (in a superconducting ring), and an applied current source. By solving an effective Shrödinger equation, we have obtained squeezed vacuum (coherent) states as the ground states of a ``free-oscillating'' (linearly-driven) Josephson junction, and calculated the uncertainties of its canonical momentum, charge, and coordinate, phase. We have also shown that the excited states of the various systems we consider are similar to the number states of a simple harmonic oscillator but with different fluctuation properties. Furthermore, we have obtained the time-evolution operators for these systems. These operators can make it easier to calculate the time-dependence of the expectation values and fluctuations of various quantities starting from an arbitrary initial state.

  6. Effect of nitrogen plasma treatment at the Al2O3/Fe interface in magnetic tunnel junction

    International Nuclear Information System (INIS)

    Shim, Heejae; Cho, B. K.; Kim, Jin-Tae; Kim, T. W.; Park, W. J.

    2003-01-01

    We investigated the effects of nitrogen plasma treatment on top surface of Fe pinned layer for short times (t ex =0, 10, 30, and 60 s) in magnetic tunnel junctions and annealing of the junctions. The nitrogen-treated junctions show much reduced magnetoresistance (MR) ratio and significantly lower resistance-area (RA) products compared with the untreated junction, i.e., MR≅3%, RA≅30 kΩ μm 2 for t ex =10 s and MR≅10%, RA≅60 kΩ μm 2 for t ex =0 s. The untreated junction showed enhanced MR ratio up to about 17% and higher RA (≅70 kΩ μm2) upon thermal annealing at T a =230 deg. C, as expected. For the nitrogen-treated junctions, while the MR ratio also increases up to about 16% upon annealing at T a =230 deg. C, which is almost the same value as the one of the optimal reference junction, the RA values of the annealed junctions still keep as low as their initial values. We believe that the redistribution of nitrogen during the annealing process is responsible for the change of properties of nitrogen-treated junction. The bias dependence of MR and the estimation of effective barrier height and thickness are studied and found to be consistent with the observed changes in nitrogen-treated junctions

  7. An isoindigo containing donor-acceptor polymer: synthesis and photovoltaic properties of all-solution-processed ITO- and vacuum-free large area roll-coated single junction and tandem solar cells

    DEFF Research Database (Denmark)

    Brandt, Rasmus Guldbæk; Yue, Wei; Andersen, Thomas Rieks

    2015-01-01

    In this work, the design, synthesis, and characterization of a donor-acceptor polymer from dithieno[3,2-b:2',3'-d]pyrrole and isoindigo (i-ID) are presented. The synthesized polymer has been applied in large area ITO-free organic photovoltaics, both as spin coated and roll coated devices; the lat......In this work, the design, synthesis, and characterization of a donor-acceptor polymer from dithieno[3,2-b:2',3'-d]pyrrole and isoindigo (i-ID) are presented. The synthesized polymer has been applied in large area ITO-free organic photovoltaics, both as spin coated and roll coated devices...

  8. The Dissolution of Double Holliday Junctions

    DEFF Research Database (Denmark)

    Bizard, Anna H; Hickson, Ian D

    2014-01-01

    as "double Holliday junction dissolution." This reaction requires the cooperative action of a so-called "dissolvasome" comprising a Holliday junction branch migration enzyme (Sgs1/BLM RecQ helicase) and a type IA topoisomerase (Top3/TopoIIIα) in complex with its OB (oligonucleotide/oligosaccharide binding......Double Holliday junctions (dHJS) are important intermediates of homologous recombination. The separate junctions can each be cleaved by DNA structure-selective endonucleases known as Holliday junction resolvases. Alternatively, double Holliday junctions can be processed by a reaction known......) fold containing accessory factor (Rmi1). This review details our current knowledge of the dissolution process and the players involved in catalyzing this mechanistically complex means of completing homologous recombination reactions....

  9. Geodynamical simulation of the RRF triple junction

    Science.gov (United States)

    Wang, Z.; Wei, D.; Liu, M.; Shi, Y.; Wang, S.

    2017-12-01

    Triple junction is the point at which three plate boundaries meet. Three plates at the triple junction form a complex geological tectonics, which is a natural laboratory to study the interactions of plates. This work studies a special triple junction, the oceanic transform fault intersects the collinear ridges with different-spreading rates, which is free of influence of ridge-transform faults and nearby hotspots. First, we build 3-D numerical model of this triple junction used to calculate the stead-state velocity and temperature fields resulting from advective and conductive heat transfer. We discuss in detail the influence of the velocity and temperature fields of the triple junction from viscosity, spreading rate of the ridge. The two sides of the oceanic transform fault are different sensitivities to the two factors. And, the influence of the velocity mainly occurs within 200km of the triple junction. Then, we modify the model by adding a ridge-transform fault to above model and directly use the velocity structure of the Macquarie triple junction. The simulation results show that the temperature at both sides of the oceanic transform fault decreases gradually from the triple junction, but the temperature difference between the two sides is a constant about 200°. And, there is little effect of upwelling velocity away from the triple junction 100km. The model results are compared with observational data. The heat flux and thermal topography along the oceanic transform fault of this model are consistent with the observed data of the Macquarie triple junction. The earthquakes are strike slip distributed along the oceanic transform fault. Their depths are also consistent with the zone of maximum shear stress. This work can help us to understand the interactions of plates of triple junctions and help us with the foundation for the future study of triple junctions.

  10. Hysteresis development in superconducting Josephson junctions

    International Nuclear Information System (INIS)

    Refai, T.F.; Shehata, L.N.

    1988-09-01

    The resistively and capacitive shunted junction model is used to investigate hysteresis development in superconducting Josephson junctions. Two empirical formulas that relate the hysteresis width and the quasi-particle diffusion length in terms of the junctions electrical parameters, temperature and frequency are obtained. The obtained formulas provide a simple tool to investigate the full potentials of the hysteresis phenomena. (author). 9 refs, 3 figs

  11. Josephson tunnel junction microwave attenuator

    DEFF Research Database (Denmark)

    Koshelets, V. P.; Shitov, S. V.; Shchukin, A. V.

    1993-01-01

    A new element for superconducting electronic circuitry-a variable attenuator-has been proposed, designed, and successfully tested. The principle of operation is based on the change in the microwave impedance of a superconductor-insulator-superconductor (SIS) Josephson tunnel junction when dc biased...... at different points in the current-voltage characteristic. Both numerical calculations based on the Tien-Gordon theory and 70-GHz microwave experiments have confirmed the wide dynamic range (more than 15-dB attenuation for one stage) and the low insertion loss in the ''open'' state. The performance of a fully...

  12. Loss models for long Josephson junctions

    DEFF Research Database (Denmark)

    Olsen, O. H.; Samuelsen, Mogens Rugholm

    1984-01-01

    A general model for loss mechanisms in long Josephson junctions is presented. An expression for the zero-field step is found for a junction of overlap type by means of a perturbation method. Comparison between analytic solution and perturbation result shows good agreement.......A general model for loss mechanisms in long Josephson junctions is presented. An expression for the zero-field step is found for a junction of overlap type by means of a perturbation method. Comparison between analytic solution and perturbation result shows good agreement....

  13. Harmonic synchronization in resistively coupled Josephson junctions

    International Nuclear Information System (INIS)

    Blackburn, J.A.; Gronbech-Jensen, N.; Smith, H.J.T.

    1994-01-01

    The oscillations of two resistively coupled Josephson junctions biased only by a single dc current source are shown to lock harmonically in a 1:2 mode over a significant range of bias current, even when the junctions are identical. The dependence of this locking on both junction and coupling parameters is examined, and it is found that, for this particular two-junction configuration, 1:1 locking can never occur, and also that a minimum coupling coefficient is needed to support harmonic locking. Some issues related to subharmonic locking are also discussed

  14. Superconducting flux qubits with π-junctions

    International Nuclear Information System (INIS)

    Shcherbakova, Anastasia

    2014-01-01

    In this thesis, we present a fabrication technology of Al/AlO x /Al Josephson junctions on Nb pads. The described technology gives the possibility of combining a variety of Nb-based superconducting circuits, like pi-junction phase-shifters with sub-micron Al/AlO x /Al junctions. Using this approach, we fabricated hybrid Nb/Al flux qubits with and without the SFS-junctions and studied dispersive magnetic field response of these qubits as well as their spectroscopy characteristics.

  15. The role of magnetic fields for curvature effects in Josephson junction

    Energy Technology Data Exchange (ETDEWEB)

    Jarmoliński, A.; Dobrowolski, T., E-mail: dobrow@up.krakow.pl

    2017-06-01

    The large area Josephson junction is considered. On the basis of Maxwell equations the influence of the magnetic field on fluxion dynamics is considered. The presented studies show that assumptions presumed in the literature do not restrict experimental settings adopted in the considerations of the fluxion movement in the Josephson junction. It is shown that the particular orientation of the magnetic fields is not needed in order to study physical effects of curvature and therefore they do not restrict the experimental arrangements.

  16. Niobium tunnel junction fabrication using e-gun evaporation and SNAP

    Science.gov (United States)

    Kortlandt, J.; van der Zant, H. S. J.; Schellingerhout, A. J. G.; Mooij, J. E.

    1990-11-01

    We have fabricated high quality small area Nb-Al-Al 2O 3-Nb junctions with SNAP, making use of e-beam evaporation in a 10 -5 Pa diffusion pumped vacuum system. Nominal dimensions of the junctions are 8x8, 4x4 and 2x2 μm 2. We obtain typical current densities of 5-6 × 10 +2A/cm 2 and (critical current) x (subgap resistance) products of 40 mV.

  17. Linker-dependent Junction Formation Probability in Single-Molecule Junctions

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Pil Sun; Kim, Taekyeong [HankukUniversity of Foreign Studies, Yongin (Korea, Republic of)

    2015-01-15

    We compare the junction formation probabilities of single-molecule junctions with different linker molecules by using a scanning tunneling microscope-based break-junction technique. We found that the junction formation probability varies as SH > SMe > NH2 for the benzene backbone molecule with different types of anchoring groups, through quantitative statistical analysis. These results are attributed to different bonding forces according to the linker groups formed with Au atoms in the electrodes, which is consistent with previous works. Our work allows a better understanding of the contact chemistry in the metal.molecule junction for future molecular electronic devices.

  18. Humidity dependence of molecular tunnel junctions with an AlOx/COOH- interface

    Science.gov (United States)

    Zhang, Xiaohang; McGill, Stephen; Xiong, Peng

    2006-03-01

    We have studied the electron transport in planar tunneling junctions with aluminum oxide and an organic self-assembled monolayer (SAM) as the tunnel barrier. The structure of the junctions is Al/AlOx/SAM/(Au, Pb) with a junction area of ˜ 0.4mm^2. The organic molecules investigated include mercaptohexadecanoic acid (MHA), hexadecanoic acid (HDA), and octadecyltrichlorosilane (OTS); all of which form ordered SAMs on top of aluminum oxide. The use of a superconducting electrode (Al) enables us to determine unambiguously that these are high-quality tunnel junctions. For junctions incorporating MHA, the transport behavior is found to be strongly humidity dependent. The resistance of these junctions drops more than 50% when placed in dry nitrogen and recovers when returned into the ambient. The same drop also occurs when the sample is placed into a vacuum, and backfilling the vacuum with either dry N2 or O2 has negligible effect on the resistance. For comparison, junctions with HDA show the same humidity dependence, while OTS samples do not. Since both MHA and HDA have carboxylic groups and OTS does not, the results suggest that water molecules at the AlOx/COOH- interface play the central role in the observed behavior. Inelastic tunneling spectroscopy (IETS) has also been performed to understand the role of water. This work was supported by a FSU Research Foundation PEG grant.

  19. Cavity syncronisation of underdamped Josephson junction arrays

    DEFF Research Database (Denmark)

    Barbara, P.; Filatrella, G.; Lobb, C.

    2003-01-01

    the junctions in the array and an electromagnetic cavity. Here we show that a model of a one-dimensional array of Josephson junctions coupled to a resonator can produce many features of the coherent be havior above threshold, including coherent radiation of power and the shape of the array current...

  20. Functional anatomy of the human ureterovesical junction

    NARCIS (Netherlands)

    Roshani, H.; Dabhoiwala, N. F.; Verbeek, F. J.; Lamers, W. H.

    1996-01-01

    BACKGROUND: The valve function of the ureterovesical-junction (UVJ) is responsible for protection of the low pressure upper urinary tract from the refluxing of urine from the bladder. Controversy about the microanatomy of the human ureterovesical-junction persists. METHODS: Ten (3 male and 7 female)

  1. Spin, Vibrations and Radiation in Superconducting Junctions

    NARCIS (Netherlands)

    Padurariu, C.

    2013-01-01

    This thesis presents the theoretical study of superconducting transport in several devices based on superconducting junctions. The important feature of these devices is that the transport properties of the junction are modified by the interaction with another physical system integrated in the

  2. Gap junctions and connexin-interacting proteins

    NARCIS (Netherlands)

    Giepmans, Ben N G

    2004-01-01

    Gap junctions form channels between adjacent cells. The core proteins of these channels are the connexins. Regulation of gap junction communication (GJC) can be modulated by connexin-associating proteins, such as regulatory protein phosphatases and protein kinases, of which c-Src is the

  3. Multiplication in Silicon p-n Junctions

    DEFF Research Database (Denmark)

    Moll, John L.

    1965-01-01

    Multiplication values were measured in the collector junctions of silicon p-n-p and n-p-n transistors before and after bombardment by 1016 neutrons/cm2. Within experimental error there was no change either in junction fields, as deduced from capacitance measurements, or in multiplication values i...

  4. impairs gap junction function causing congenital cataract

    Indian Academy of Sciences (India)

    Navya

    2017-03-24

    Mar 24, 2017 ... experiment showed a lower dye diffusion distance of Cx46 V44M cells, ... Studies of connexins show that channel gating and permeability .... have found that connexin assembled into gap junction plaques is not soluble in 1% ..... high glucose reduces gap junction activity in microvascular endothelial cells.

  5. impairs gap junction function causing congenital cataract

    Indian Academy of Sciences (India)

    LIJUAN CHEN

    2017-12-20

    Dec 20, 2017 ... showed a lower dye diffusion distance of Cx46 V44M cells, which indicates that the gap junction intercellular ... permeability could be affected by alterations of charged residues of .... bled into gap junction plaques is not soluble in 1% Triton ..... regulation of connexin 43 expression by high glucose reduces.

  6. Overlap junctions for high coherence superconducting qubits

    Science.gov (United States)

    Wu, X.; Long, J. L.; Ku, H. S.; Lake, R. E.; Bal, M.; Pappas, D. P.

    2017-07-01

    Fabrication of sub-micron Josephson junctions is demonstrated using standard processing techniques for high-coherence, superconducting qubits. These junctions are made in two separate lithography steps with normal-angle evaporation. Most significantly, this work demonstrates that it is possible to achieve high coherence with junctions formed on aluminum surfaces cleaned in situ by Ar plasma before junction oxidation. This method eliminates the angle-dependent shadow masks typically used for small junctions. Therefore, this is conducive to the implementation of typical methods for improving margins and yield using conventional CMOS processing. The current method uses electron-beam lithography and an additive process to define the top and bottom electrodes. Extension of this work to optical lithography and subtractive processes is discussed.

  7. Resonance Transport of Graphene Nanoribbon T-Shaped Junctions

    International Nuclear Information System (INIS)

    Xiao-Lan, Kong; Yong-Jian, Xiong

    2010-01-01

    We investigate the transport properties of T-shaped junctions composed of armchair graphene nanoribbons of different widths. Three types of junction geometries are considered. The junction conductance strongly depends on the atomic features of the junction geometry. When the shoulders of the junction have zigzag type edges, sharp conductance resonances usually appear in the low energy region around the Dirac point, and a conductance gap emerges. When the shoulders of the junction have armchair type edges, the conductance resonance behavior is weakened significantly, and the metal-metal-metal junction structures show semimetallic behaviors. The contact resistance also changes notably due to the various interface geometries of the junction

  8. Diagnosis and management of anomalies of the craniovertebral junction.

    Science.gov (United States)

    Kumar, A; Jafar, J; Mafee, M; Glick, R

    1986-01-01

    The term craniovertebral junction refers to an area comprising the inferior portion of the occipital bone surrounding the foramen magnum and the first two cervical vertebrae. A variety of anomalies of bony, meningeal, and neural elements are known to occur in this region, producing a wide spectrum of clinical symptoms. These can range from dizziness, ataxia, and nuchal headaches to obvious quadriparesis and cranial nerve palsies. Often the symptoms are vague with an evolution marked by temporary exacerbations and remissions. The diagnosis can be difficult, and in our experience is best achieved by combining a neurotologic and neurologic evaluation. We discuss here the symptoms and diagnosis in ten patients with lesions at the craniovertebral junction. The surgical management of two cases of basilar invagination is described, and the controversies regarding the technique are discussed.

  9. NIS tunnel junction as an x-ray photon sensor

    Science.gov (United States)

    Azgui, Fatma; Mears, Carl A.; Labov, Simon E.; Frank, Matthias A.; Sadoulet, Bernard; Brunet, E.; Hiller, Lawrence J.; Lindeman, Mark A.; Netel, Harrie

    1995-09-01

    This work presents the first results of our development of normal-insulating-superconducting tunnel junctions used as energy dispersive detectors for low energy particles. The device described here is a Ag/Al(subscript 2)O(subscript 3)/Al tunnel junction of area 1.5 multiplied by 10(superscript 4) micrometer squared with thicknesses of 200 nm for the normal Ag strip and 100 nm for the superconducting Al film. Two different high-speed SQUID systems manufactured by quantum magnetics and HYPRES, respectively, were used for the readout of this device. At 80 mK bath temperature we obtained an energy resolution DeltaE(subscript FWHM) equals 250 eV for 5.89 keV x rays absorbed directly in the normal metal. This energy resolution appears to be limited in large part by the observed strong position dependence of the device response.

  10. Self-positioned thin Pb-alloy base electrode Josephson junction

    International Nuclear Information System (INIS)

    Kuroda, K.; Sato, K.

    1986-01-01

    A self-positioned thin (SPOT) Pb-alloy base electrode Josephson junction is developed. In this junction, a 50-nm thick Pb-alloy base electrode is restricted within the junction region on an Nb underlayer using a self-alignment technique. The grain size reduction and the base electrode area restriction greatly improve thermal cycling stability, where the thermal cycling tests of 4000 proposed junctions (5 x 5 μm 2 ) showed no failures after 4000 cycles. In addition, the elimination of insulator layer stress on the Pb-alloy base electrode rectifies the problem of size effect on current density. The Nb underlayers also serve to isolate the Pb-alloy base electrodes from the resistors

  11. Vortex trapping in Pb-alloy Josephson junctions induced by strong sputtering of the base electrode

    International Nuclear Information System (INIS)

    Wada, M.; Nakano, J.; Yanagawa, F.

    1985-01-01

    It is observed that strong rf sputtering of the Pb-alloy base electrodes causes the junctions to trap magnetic vortices and thus induces Josephson current (I/sub J/) suppression. Trapping begins to occur when the rf sputtering that removes the native thermal oxide on the base electrode is carried out prior to rf plasma oxidation. Observed large I/sub J/ suppression is presumably induced by the concentration of vortices into the sputtered area upon cooling the sample below the transition temperature. This suggests a new method of the circumvention of the vortex trapping by strongly rf sputtering the areas of the electrode other than the junction areas

  12. Electron optics with ballistic graphene junctions

    Science.gov (United States)

    Chen, Shaowen

    Electrons transmitted across a ballistic semiconductor junction undergo refraction, analogous to light rays across an optical boundary. A pn junction theoretically provides the equivalent of a negative index medium, enabling novel electron optics such as negative refraction and perfect (Veselago) lensing. In graphene, the linear dispersion and zero-gap bandstructure admit highly transparent pn junctions by simple electrostatic gating, which cannot be achieved in conventional semiconductors. Robust demonstration of these effects, however, has not been forthcoming. Here we employ transverse magnetic focusing to probe propagation across an electrostatically defined graphene junction. We find perfect agreement with the predicted Snell's law for electrons, including observation of both positive and negative refraction. Resonant transmission across the pn junction provides a direct measurement of the angle dependent transmission coefficient, and we demonstrate good agreement with theory. Comparing experimental data with simulation reveals the crucial role played by the effective junction width, providing guidance for future device design. Efforts toward sharper pn junction and possibility of zero field Veselago lensing will also be discussed. This work is supported by the Semiconductor Research Corporations NRI Center for Institute for Nanoelectronics Discovery and Exploration (INDEX).

  13. Valley dependent transport in graphene L junction

    Science.gov (United States)

    Chan, K. S.

    2018-05-01

    We studied the valley dependent transport in graphene L junctions connecting an armchair lead and a zigzag lead. The junction can be used in valleytronic devices and circuits. Electrons injected from the armchair lead into the junction is not valley polarized, but they can become valley polarized in the zigzag lead. There are Fermi energies, where the current in the zigzag lead is highly valley polarized and the junction is an efficient generator of valley polarized current. The features of the valley polarized current depend sensitively on the widths of the two leads, as well as the number of dimers in the armchair lead, because this number has a sensitive effect on the band structure of the armchair lead. When an external potential is applied to the junction, the energy range with high valley polarization is enlarged enhancing its function as a generator of highly valley polarized current. The scaling behavior found in other graphene devices is also found in L junctions, which means that the results presented here can be extended to junctions with larger dimensions after appropriate scaling of the energy.

  14. Shot noise in YBCO bicrystal Josephson junctions

    DEFF Research Database (Denmark)

    Constantinian, K.Y.; Ovsyannikov, G.A.; Borisenko, I.V.

    2003-01-01

    We measured spectral noise density in YBCO symmetric bicrystal Josephson junctions on sapphire substrates at bias voltages up to 100 mV and T 4.2 K. Normal state resistance of the Josephson junctions, R-N = 20-90 Omega and ICRN up to 2.2 mV have been observed in the experimental samples. Noise...... may explain the experimentally measured linewidth broadening of Josephson oscillations at mm and submm wave frequencies in high-Tc superconducting junctions. Experimental results are discussed in terms of bound states existing at surfaces of d-wave superconducting electrodes....

  15. delta-biased Josephson tunnel junctions

    DEFF Research Database (Denmark)

    Monaco, R.; Mygind, Jesper; Koshelet, V.

    2010-01-01

    Abstract: The behavior of a long Josephson tunnel junction drastically depends on the distribution of the dc bias current. We investigate the case in which the bias current is fed in the central point of a one-dimensional junction. Such junction configuration has been recently used to detect...... the persistent currents circulating in a superconducting loop. Analytical and numerical results indicate that the presence of fractional vortices leads to remarkable differences from the conventional case of uniformly distributed dc bias current. The theoretical findings are supported by detailed measurements...

  16. Parametric frequency conversion in long Josephson junctions

    International Nuclear Information System (INIS)

    Irie, F.; Ashihara, S.; Yoshida, K.

    1976-01-01

    Current steps at voltages corresponding to the parametric coupling between an applied r.f. field and junction resonant modes have been observed in long Josephson tunnel junctions in the flux-flow state. The observed periodic variations of the step height due to the applied magnetic field are explained quantitatively by a perturbational analysis using Josephson phase equations. The present study demonstrates that the moving vortex array can serve as a coherent pump wave for signal waves propagating in the barrier region, which indicates, as a result, the possibility of traveling-wave parametric devices with long Josephson tunnel junctions. (author)

  17. Tunnel junctions with multiferroic barriers

    Science.gov (United States)

    Gajek, Martin; Bibes, Manuel; Fusil, Stéphane; Bouzehouane, Karim; Fontcuberta, Josep; Barthélémy, Agnès; Fert, Albert

    2007-04-01

    Multiferroics are singular materials that can exhibit simultaneously electric and magnetic orders. Some are ferroelectric and ferromagnetic and provide the opportunity to encode information in electric polarization and magnetization to obtain four logic states. However, such materials are rare and schemes allowing a simple electrical readout of these states have not been demonstrated in the same device. Here, we show that films of La0.1Bi0.9MnO3 (LBMO) are ferromagnetic and ferroelectric, and retain both ferroic properties down to a thickness of 2nm. We have integrated such ultrathin multiferroic films as barriers in spin-filter-type tunnel junctions that exploit the magnetic and ferroelectric degrees of freedom of LBMO. Whereas ferromagnetism permits read operations reminiscent of magnetic random access memories (MRAM), the electrical switching evokes a ferroelectric RAM write operation. Significantly, our device does not require the destructive ferroelectric readout, and therefore represents an advance over the original four-state memory concept based on multiferroics.

  18. Chirality effect in disordered graphene ribbon junctions

    International Nuclear Information System (INIS)

    Long Wen

    2012-01-01

    We investigate the influence of edge chirality on the electronic transport in clean or disordered graphene ribbon junctions. By using the tight-binding model and the Landauer-Büttiker formalism, the junction conductance is obtained. In the clean sample, the zero-magnetic-field junction conductance is strongly chirality-dependent in both unipolar and bipolar ribbons, whereas the high-magnetic-field conductance is either chirality-independent in the unipolar or chirality-dependent in the bipolar ribbon. Furthermore, we study the disordered sample in the presence of magnetic field and find that the junction conductance is always chirality-insensitive for both unipolar and bipolar ribbons with adequate disorders. In addition, the disorder-induced conductance plateaus can exist in all chiral bipolar ribbons provided the disorder strength is moderate. These results suggest that we can neglect the effect of edge chirality in fabricating electronic devices based on the magnetotransport in a disordered graphene ribbon. (paper)

  19. Josephson tunnel junctions in niobium films

    International Nuclear Information System (INIS)

    Wiik, Tapio.

    1976-12-01

    A method of fabricating stable Josephson tunnel junctions with reproducible characteristics is described. The junctions have a sandwich structure consisting of a vacuum evaporated niobium film, a niobium oxide layer produced by the glow discharge method and a lead film deposited by vacuum evaporation. Difficulties in producing thin-film Josephson junctions are discussed. Experimental results suggest that the lower critical field of the niobium film is the most essential parameter when evaluating the quality of these junctions. The dependence of the lower critical field on the film thickness and on the Ginzburg-Landau parameter of the film is studied analytically. Comparison with the properties of the evaporated films and with the previous calculations for bulk specimens shows that the presented model is applicable for most of the prepared samples. (author)

  20. Transparency of atom-sized superconducting junctions

    International Nuclear Information System (INIS)

    Van-der-Post, N.; Peters, E.T.; Van Ruitenbeek, J.M.; Yanson, I.K.

    1995-01-01

    We discuss the transparency of atom-size superconducting tunnel junctions by comparing experimental values of the normal resistance and Subgap Structure with the theoretical predictions for these phenomena by Landauer's formula and Multiple Andreev Reflection, respectively

  1. Josephson junction arrays and superconducting wire networks

    International Nuclear Information System (INIS)

    Lobb, C.J.

    1992-01-01

    Techniques used to fabricate integrated circuits make it possible to construct superconducting networks containing as many as 10 6 wires or Josephson junctions. Such networks undergo phase transitions from resistive high-temperature states to ordered low-resistance low-temperature states. The nature of the phase transition depends strongly on controllable parameters such as the strength of the superconductivity in each wire or junction and the external magnetic field. This paper will review the physics of these phase transitions, starting with the simplest zero-magnetic field case. This leads to a Kosterlitz-Thouless transition when the junctions or wires are weak, and a simple mean-field fransition when the junctions or wires are strong. Rich behavior, resulting from frustration, occurs in the presence of a magnetic field. (orig.)

  2. Neutron induced permanent damage in Josephson junctions

    International Nuclear Information System (INIS)

    Mueller, G.P.; Rosen, M.

    1982-01-01

    14 MeV neutron induced permanent changes in the critical current density of Josephson junctions due to displacement damage in the junction barrier are estimated using a worst case model and the binary collision simulation code MARLOWE. No likelihood of single event hard upsets is found in this model. It is estimated that a fluence of 10 18 -10 19 neutrons/cm 2 are required to change the critical current density by 5%

  3. Exotic hadron and string junction model

    International Nuclear Information System (INIS)

    Imachi, Masahiro

    1978-01-01

    Hadron structure is investigated adopting string junction model as a realization of confinement. Besides exotic hadrons (M 4 , B 5 etc.), unconventional hadrons appear. A mass formula for these hadrons is proposed. New selection rule is introduced which requires the covalence of constituent line at hadron vertex. New duality appears due to the freedom of junction, especially in anti BB→anti BB reaction. A possible assignment of exotic and unconventional hadrons to recently observed narrow meson states is presented. (auth.)

  4. Construction of tunable peptide nucleic acid junctions.

    Science.gov (United States)

    Duan, Tanghui; He, Liu; Tokura, Yu; Liu, Xin; Wu, Yuzhou; Shi, Zhengshuang

    2018-03-15

    We report here the construction of 3-way and 4-way peptide nucleic acid (PNA) junctions as basic structural units for PNA nanostructuring. The incorporation of amino acid residues into PNA chains makes PNA nanostructures with more structural complexity and architectural flexibility possible, as exemplified by building 3-way PNA junctions with tunable nanopores. Given that PNA nanostructures have good thermal and enzymatic stabilities, they are expected to have broad potential applications in biosensing, drug delivery and bioengineering.

  5. Molecular Diffusion through Cyanobacterial Septal Junctions.

    Science.gov (United States)

    Nieves-Morión, Mercedes; Mullineaux, Conrad W; Flores, Enrique

    2017-01-03

    Heterocyst-forming cyanobacteria grow as filaments in which intercellular molecular exchange takes place. During the differentiation of N 2 -fixing heterocysts, regulators are transferred between cells. In the diazotrophic filament, vegetative cells that fix CO 2 through oxygenic photosynthesis provide the heterocysts with reduced carbon and heterocysts provide the vegetative cells with fixed nitrogen. Intercellular molecular transfer has been traced with fluorescent markers, including calcein, 5-carboxyfluorescein, and the sucrose analogue esculin, which are observed to move down their concentration gradient. In this work, we used fluorescence recovery after photobleaching (FRAP) assays in the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 to measure the temperature dependence of intercellular transfer of fluorescent markers. We find that the transfer rate constants are directly proportional to the absolute temperature. This indicates that the "septal junctions" (formerly known as "microplasmodesmata") linking the cells in the filament allow molecular exchange by simple diffusion, without any activated intermediate state. This constitutes a novel mechanism for molecular transfer across the bacterial cytoplasmic membrane, in addition to previously characterized mechanisms for active transport and facilitated diffusion. Cyanobacterial septal junctions are functionally analogous to the gap junctions of metazoans. Although bacteria are frequently considered just as unicellular organisms, there are bacteria that behave as true multicellular organisms. The heterocyst-forming cyanobacteria grow as filaments in which cells communicate. Intercellular molecular exchange is thought to be mediated by septal junctions. Here, we show that intercellular transfer of fluorescent markers in the cyanobacterial filament has the physical properties of simple diffusion. Thus, cyanobacterial septal junctions are functionally analogous to metazoan gap junctions

  6. Spinal Gap Junction Channels in Neuropathic Pain

    OpenAIRE

    Jeon, Young Hoon; Youn, Dong Ho

    2015-01-01

    Damage to peripheral nerves or the spinal cord is often accompanied by neuropathic pain, which is a complex, chronic pain state. Increasing evidence indicates that alterations in the expression and activity of gap junction channels in the spinal cord are involved in the development of neuropathic pain. Thus, this review briefly summarizes evidence that regulation of the expression, coupling, and activity of spinal gap junction channels modulates pain signals in neuropathic pain states induced...

  7. Performance comparison between p–i–n and p–n junction tunneling field-effect transistors

    Science.gov (United States)

    Yoon, Young Jun; Seo, Jae Hwa; Kang, In Man

    2018-06-01

    In this study, we investigated the direct-current (DC) and radio-frequency (RF) performances of p–i–n and p–n junction tunneling field-effect transistors (TFETs). Compared to the p–i–n junction TFET, the p–n junction TFET exhibited higher on-state current (I on) because the channel formation mechanism of the p–n junction TFET resulted in a narrower tunneling barrier and an expanded tunneling area. Further, the reduction of I on of the p–n junction TFET by the interface trap was smaller. Moreover, the p–n junction TFET exhibited lower gate-to-drain capacitance (C gd) because a depletion capacitance (C gd,dep) was formed by the depletion region under gate dielectric. Consequently, the p–n junction TFET achieved an improvement of cut-off frequency (f T) and intrinsic delay time (τ), which are related to the current performance and total gate capacitance (C gg). We confirmed the enhancement of device performances in terms of I on, f T, and τ by the conduction mechanism of the p–n junction TFET.

  8. Ballistic Josephson junctions based on CVD graphene

    Science.gov (United States)

    Li, Tianyi; Gallop, John; Hao, Ling; Romans, Edward

    2018-04-01

    Josephson junctions with graphene as the weak link between superconductors have been intensely studied in recent years, with respect to both fundamental physics and potential applications. However, most of the previous work was based on mechanically exfoliated graphene, which is not compatible with wafer-scale production. To overcome this limitation, we have used graphene grown by chemical vapour deposition (CVD) as the weak link of Josephson junctions. We demonstrate that very short, wide CVD-graphene-based Josephson junctions with Nb electrodes can work without any undesirable hysteresis in their electrical characteristics from 1.5 K down to a base temperature of 320 mK, and their gate-tuneable critical current shows an ideal Fraunhofer-like interference pattern in a perpendicular magnetic field. Furthermore, for our shortest junctions (50 nm in length), we find that the normal state resistance oscillates with the gate voltage, consistent with the junctions being in the ballistic regime, a feature not previously observed in CVD-graphene-based Josephson junctions.

  9. Junction depth measurement using carrier illumination

    International Nuclear Information System (INIS)

    Borden, Peter

    2001-01-01

    Carrier Illumination [trade mark] (CI) is a new method recently developed to meet the need for a non-destructive, high throughput junction depth measurement on patterned wafers. A laser beam creates a quasi-static excess carrier profile in the semiconductor underlying the activated junction. The excess carrier profile is fairly constant below the junction, and drops rapidly in the junction, creating a steep index of refraction gradient at the junction edge. Interference with light reflected from this index gradient provides a signal that is analyzed to determine the junction depth. The paper summarizes evaluation of performance in full NMOS and PMOS process flows, on both bare and patterned wafers. The aims have been to validate (1) performance in the presence of underlying layers typically found at the source/drain (S/D) process steps and (2) measurement on patterned wafers. Correlation of CI measurements to SIMS and transistor drive current are shown. The data were obtained from NMOS structures using As S/D and LDD implants. Correlations to SRP, SIMS and sheet resistance are shown for PMOS structures using B 11 LDD implants. Gage capability measurements are also presented

  10. Test-beds for molecular electronics: metal-molecules-metal junctions based on Hg electrodes.

    Science.gov (United States)

    Simeone, Felice Carlo; Rampi, Maria Anita

    2010-01-01

    Junctions based on mesoscopic Hg electrodes are used to characterize the electrical properties of the organic molecules organized in self-assembled monolayers (SAMs). The junctions M-SAM//SAM-Hg are formed by one electrode based on metals (M) such as Hg, Ag, Au, covered by a SAM, and by a second electrode always formed by a Hg drop carrying also a SAM. The electrodes, brought together by using a micromanipulator, sandwich SAMs of different nature at the contact area (approximately = 0.7 microm2). The high versatility of the system allows a series of both electrical and electrochemical junctions to be assembled and characterized: (i) The compliant nature of the Hg electrodes allows incorporation into the junction and measurement of the electrical behavior of a large number of molecular systems and correlation of their electronic structure to the electrical behavior; (ii) by functionalizing both electrodes with SAMs exposing different functional groups, X and Y, it is possible to compare the rate of electron transfer through different X...Y molecular interactions; (iii) when the junction incorporates one of the electrode formed by a semitransparent film of Au, it allows electrical measurements under irradiation of the sandwiched SAMs. In this case the junction behaves as a photoswitch; iv) incorporation of redox centres with low lying, easily reachable energy levels, provides electron stations as indicated by the hopping mechanism dominating the current flow; (v) electrochemical junctions incorporating redox centres by both covalent and electrostatic interactions permit control of the potential of the electrodes with respect to that of the redox state by means of an external reference electrode. Both these junctions show an electrical behavior similar to that of conventional diodes, even though the mechanism generating the current flow is different. These systems, demonstrating high mechanical stability and reproducibility, easy assembly, and a wide variety of

  11. Marker of cemento-periodontal ligament junction associated with periodontal regeneration.

    Science.gov (United States)

    Hara, Ryohko; Wato, Masahiro; Tanaka, Akio

    2005-06-01

    The purpose of this study was to identify factors promoting formation of the cemento-periodontal ligament junction. Regeneration of the cemento-periodontal ligament junction is an important factor in recovery of the connective tissue attachment to the cementum and it is important to identify all specific substances that promote its formation. To clarify the substances involved in cemento-periodontal ligament junction formation, we produced a monoclonal antibody (mAb) to human cemento-periodontal ligament junction (designated as the anti-TAP mAb) and examined its immunostaining properties and reactive antigen. Hybridomas producing monoclonal antibody against human cemento-periodontal ligament junction antigens were established by fusing P3U1 mouse myeloma cells with spleen cells from BALB/c mice immunized with homogenized human cemento-periodontal ligament junction. The mAb, the anti-TAP mAb for cemento-periodontal ligament junction, was then isolated. The immunoglobulin class and light chain of the mAb were examined using an isotyping kit. Before immunostaining, antigen determination using an enzymatic method or heating was conducted. Human teeth, hard tissue-forming lesions, and animal tissues were immunostained by the anti-TAP mAb. The anti-TAP mAb was positive in human cemento-periodontal ligament junction and predentin but negative in all other human and animal tissues examined. In the cemento-osseous lesions, the anti-TAP mAb was positive in the peripheral area of the cementum and cementum-like hard tissues and not in the bone and bone-like tissues. The anti-TAP mAb showed IgM (kappa) and recognized phosphoprotein. The anti-TAP mAb is potentially useful for developing new agents promoting cementogenesis and periodontal regeneration.

  12. Effect of reinforcement on plastic limit loads of branch junctions

    International Nuclear Information System (INIS)

    Kim, Yun-Jae; Myeong, Man-Sik; Yoon, Kee-Bong

    2009-01-01

    This paper provides effects of reinforcement shape and area on plastic limit loads of branch junctions under internal pressure and in-plane/out-of-plane bending, via detailed three-dimensional finite element limit analysis assuming elastic-perfectly plastic material behaviour. It is found that reinforcement is most effective when (in-plane/out-of-plane) bending is applied to the branch pipe. When bending is applied to the run pipe, reinforcement is less effective when bending is applied to the branch pipe. The reinforcement effect is the least effective for internal pressure.

  13. Magnetic tunnel junction thermocouple for thermoelectric power harvesting

    Science.gov (United States)

    Böhnert, T.; Paz, E.; Ferreira, R.; Freitas, P. P.

    2018-05-01

    The thermoelectric power generated in magnetic tunnel junctions (MTJs) is determined as a function of the tunnel barrier thickness for a matched electric circuit. This study suggests that lower resistance area product and higher tunnel magnetoresistance will maximize the thermoelectric power output of the MTJ structures. Further, the thermoelectric behavior of a series of two MTJs, a MTJ thermocouple, is investigated as a function of its magnetic configurations. In an alternating magnetic configurations the thermovoltages cancel each other, while the magnetic contribution remains. A large array of MTJ thermocouples could amplify the magnetic thermovoltage signal significantly.

  14. Advanced Metrology for Characterization of Magnetic Tunnel Junctions

    DEFF Research Database (Denmark)

    Kjær, Daniel

    -plane tunneling (CIPT) for characterization of magnetic tunnel junctions (MTJs), which constitutes the key component not only in MRAM but also the read-heads of modern hard disk drives. MTJs are described by their tunnel magnetoresistance (TMR), which is the relative difference of the resistance area products (RA...... of this project has been to provide cheaper, faster and more precise metrology for MTJs. This goal has been achieved in part by the demonstration of a static field CIPT method, which allows us to reduce the measurement time by a factor of 5, by measuring only RA thus excluding TMR. This enhancement is obtained...

  15. Graphene-Based Josephson-Junction Single-Photon Detector

    Science.gov (United States)

    Walsh, Evan D.; Efetov, Dmitri K.; Lee, Gil-Ho; Heuck, Mikkel; Crossno, Jesse; Ohki, Thomas A.; Kim, Philip; Englund, Dirk; Fong, Kin Chung

    2017-08-01

    We propose to use graphene-based Josephson junctions (GJJs) to detect single photons in a wide electromagnetic spectrum from visible to radio frequencies. Our approach takes advantage of the exceptionally low electronic heat capacity of monolayer graphene and its constricted thermal conductance to its phonon degrees of freedom. Such a system could provide high-sensitivity photon detection required for research areas including quantum information processing and radio astronomy. As an example, we present our device concepts for GJJ single-photon detectors in both the microwave and infrared regimes. The dark count rate and intrinsic quantum efficiency are computed based on parameters from a measured GJJ, demonstrating feasibility within existing technologies.

  16. Josephson junctions of multiple superconducting wires

    Science.gov (United States)

    Deb, Oindrila; Sengupta, K.; Sen, Diptiman

    2018-05-01

    We study the spectrum of Andreev bound states and Josephson currents across a junction of N superconducting wires which may have s - or p -wave pairing symmetries and develop a scattering matrix based formalism which allows us to address transport across such junctions. For N ≥3 , it is well known that Berry curvature terms contribute to the Josephson currents; we chart out situations where such terms can have relatively large effects. For a system of three s -wave or three p -wave superconductors, we provide analytic expressions for the Andreev bound-state energies and study the Josephson currents in response to a constant voltage applied across one of the wires; we find that the integrated transconductance at zero temperature is quantized to integer multiples of 4 e2/h , where e is the electron charge and h =2 π ℏ is Planck's constant. For a sinusoidal current with frequency ω applied across one of the wires in the junction, we find that Shapiro plateaus appear in the time-averaged voltage across that wire for any rational fractional multiple (in contrast to only integer multiples in junctions of two wires) of 2 e /(ℏ ω ) . We also use our formalism to study junctions of two p -wave and one s -wave wires. We find that the corresponding Andreev bound-state energies depend on the spin of the Bogoliubov quasiparticles; this produces a net magnetic moment in such junctions. The time variation of these magnetic moments may be controlled by an external voltage applied across the junction. We discuss experiments which may test our theory.

  17. Josephson tunnel junctions with ferromagnetic interlayer

    International Nuclear Information System (INIS)

    Weides, M.P.

    2006-01-01

    Superconductivity and ferromagnetism are well-known physical properties of solid states that have been widely studied and long thought about as antagonistic phenomena due to difference in spin ordering. It turns out that the combination of both superconductor and ferromagnet leads to a very rich and interesting physics. One particular example, the phase oscillations of the superconducting order parameter inside the ferromagnet, will play a major role for the devices discussed in this work. In this thesis, I present Josephson junctions with a thin Al 2 O 3 tunnel barrier and a ferromagnetic interlayer, i.e. superconductor-insulator-ferromagnet-superconductor (SIFS) stacks. The fabrication of junctions was optimized regarding the insulation of electrodes and the homogeneity of the current transport. The junctions were either in the 0 or π coupled ground state, depending on the thickness of the ferromagnetic layer and on temperature. The influence of ferromagnetic layer thickness on the transport properties and the coupling (0, π) of SIFS tunnel junctions was studied. Furthermore, using a stepped ferromagnetic layer with well-chosen thicknesses, I obtained the so-called 0-π Josephson junction. At a certain temperature this 0-π junction can be made perfectly symmetric. In this case the ground state corresponds to a vortex of supercurrent creating a magnetic flux which is a fraction of the magnetic flux quantum Φ 0 . Such structures allow to study the physics of fractional vortices and to build various electronic circuits based on them. The SIFS junctions presented here have an exponentially vanishing damping at T → 0. The SIFS technology developed within the framework of this work may be used to construct classical and quantum devices such as oscillators, memory cells and qubits. (orig.)

  18. Josephson tunnel junctions with ferromagnetic interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Weides, M.P.

    2006-07-01

    Superconductivity and ferromagnetism are well-known physical properties of solid states that have been widely studied and long thought about as antagonistic phenomena due to difference in spin ordering. It turns out that the combination of both superconductor and ferromagnet leads to a very rich and interesting physics. One particular example, the phase oscillations of the superconducting order parameter inside the ferromagnet, will play a major role for the devices discussed in this work. In this thesis, I present Josephson junctions with a thin Al{sub 2}O{sub 3} tunnel barrier and a ferromagnetic interlayer, i.e. superconductor-insulator-ferromagnet-superconductor (SIFS) stacks. The fabrication of junctions was optimized regarding the insulation of electrodes and the homogeneity of the current transport. The junctions were either in the 0 or {pi} coupled ground state, depending on the thickness of the ferromagnetic layer and on temperature. The influence of ferromagnetic layer thickness on the transport properties and the coupling (0, {pi}) of SIFS tunnel junctions was studied. Furthermore, using a stepped ferromagnetic layer with well-chosen thicknesses, I obtained the so-called 0-{pi} Josephson junction. At a certain temperature this 0-{pi} junction can be made perfectly symmetric. In this case the ground state corresponds to a vortex of supercurrent creating a magnetic flux which is a fraction of the magnetic flux quantum {phi}{sub 0}. Such structures allow to study the physics of fractional vortices and to build various electronic circuits based on them. The SIFS junctions presented here have an exponentially vanishing damping at T {yields} 0. The SIFS technology developed within the framework of this work may be used to construct classical and quantum devices such as oscillators, memory cells and qubits. (orig.)

  19. Ballistic Graphene Josephson Junctions from the Short to the Long Junction Regimes.

    Science.gov (United States)

    Borzenets, I V; Amet, F; Ke, C T; Draelos, A W; Wei, M T; Seredinski, A; Watanabe, K; Taniguchi, T; Bomze, Y; Yamamoto, M; Tarucha, S; Finkelstein, G

    2016-12-02

    We investigate the critical current I_{C} of ballistic Josephson junctions made of encapsulated graphene-boron-nitride heterostructures. We observe a crossover from the short to the long junction regimes as the length of the device increases. In long ballistic junctions, I_{C} is found to scale as ∝exp(-k_{B}T/δE). The extracted energies δE are independent of the carrier density and proportional to the level spacing of the ballistic cavity. As T→0 the critical current of a long (or short) junction saturates at a level determined by the product of δE (or Δ) and the number of the junction's transversal modes.

  20. Increasing gap junctional coupling: a tool for dissecting the role of gap junctions

    DEFF Research Database (Denmark)

    Axelsen, Lene Nygaard; Haugan, Ketil; Stahlhut, Martin

    2007-01-01

    Much of our current knowledge about the physiological and pathophysiological role of gap junctions is based on experiments where coupling has been reduced by either chemical agents or genetic modification. This has brought evidence that gap junctions are important in many physiological processes....... In a number of cases, gap junctions have been implicated in the initiation and progress of disease, and experimental uncoupling has been used to investigate the exact role of coupling. The inverse approach, i.e., to increase coupling, has become possible in recent years and represents a new way of testing...... the role of gap junctions. The aim of this review is to summarize the current knowledge obtained with agents that selectively increase gap junctional intercellular coupling. Two approaches will be reviewed: increasing coupling by the use of antiarrhythmic peptide and its synthetic analogs...

  1. A single-gradient junction technique to replace multiple-junction shifts for craniospinal irradiation treatment

    International Nuclear Information System (INIS)

    Hadley, Austin; Ding, George X.

    2014-01-01

    Craniospinal irradiation (CSI) requires abutting fields at the cervical spine. Junction shifts are conventionally used to prevent setup error–induced overdosage/underdosage from occurring at the same location. This study compared the dosimetric differences at the cranial-spinal junction between a single-gradient junction technique and conventional multiple-junction shifts and evaluated the effect of setup errors on the dose distributions between both techniques for a treatment course and single fraction. Conventionally, 2 lateral brain fields and a posterior spine field(s) are used for CSI with weekly 1-cm junction shifts. We retrospectively replanned 4 CSI patients using a single-gradient junction between the lateral brain fields and the posterior spine field. The fields were extended to allow a minimum 3-cm field overlap. The dose gradient at the junction was achieved using dose painting and intensity-modulated radiation therapy planning. The effect of positioning setup errors on the dose distributions for both techniques was simulated by applying shifts of ± 3 and 5 mm. The resulting cervical spine doses across the field junction for both techniques were calculated and compared. Dose profiles were obtained for both a single fraction and entire treatment course to include the effects of the conventional weekly junction shifts. Compared with the conventional technique, the gradient-dose technique resulted in higher dose uniformity and conformity to the target volumes, lower organ at risk (OAR) mean and maximum doses, and diminished hot spots from systematic positioning errors over the course of treatment. Single-fraction hot and cold spots were improved for the gradient-dose technique. The single-gradient junction technique provides improved conformity, dose uniformity, diminished hot spots, lower OAR mean and maximum dose, and one plan for the entire treatment course, which reduces the potential human error associated with conventional 4-shifted plans

  2. Particle detection with superconducting tunnel junctions

    International Nuclear Information System (INIS)

    Jany, P.

    1990-08-01

    At the Institute of Experimental Nuclear Physics of the University of Karlsruhe (TH) and at the Institute for Nuclear Physics of the Kernforschungszentrum Karlsruhe we started to produce superconducting tunnel junctions and to investigate them for their suitability as particle detectors. The required facilities for the production of tunnel junctions and the experimental equipments to carry out experiments with them were erected. Experiments are presented in which radiations of different kinds of particles could successfully be measured with the tunnel junctions produced. At first we succeeded in detectioning light pulses of a laser. In experiments with alpha-particles of an energy of 4,6 MeV the alpha-particles were detected with an energy resolution of 1,1%, and it was shown in specific experiments that the phonons originating from the deposition of energy by an alpha-particle in the substrate can be detected with superconducting tunnel junctions at the surface. On that occasion it turned out that the signals could be separated with respect to their point of origin (tunnel junction, contact leads, substrate). Finally X-rays with an energy of 6 keV were detected with an energy resolution of 8% in a test arrangement that makes use of the so-called trapping effect to read out a larger absorber volume. (orig.) [de

  3. Terahertz Responses of Intrinsic Josephson Junctions in High TC Superconductors

    International Nuclear Information System (INIS)

    Wang, H. B.; Wu, P. H.; Yamashita, T.

    2001-01-01

    High frequency responses of intrinsic Josephson junctions up to 2.5THz, including the observation of Shapiro steps under various conditions, are reported and discussed in this Letter. The sample was an array of intrinsic Josephson junctions singled out from inside a high T C superconducting Bi 2 Sr 2 CaCu 2 O 8+x single crystal, with a bow-tie antenna integrated to it. The number of junctions in the array was controllable, the junctions were homogeneous, the distribution of applied irradiation among the junctions was even, and the junctions could synchronously respond to high frequency irradiation

  4. Phase-dependent noise in Josephson junctions

    Science.gov (United States)

    Sheldon, Forrest; Peotta, Sebastiano; Di Ventra, Massimiliano

    2018-03-01

    In addition to the usual superconducting current, Josephson junctions (JJs) support a phase-dependent conductance related to the retardation effect of tunneling quasi-particles. This introduces a dissipative current with a memory-resistive (memristive) character that should also affect the current noise. By means of the microscopic theory of tunnel junctions we compute the complete current autocorrelation function of a Josephson tunnel junction and show that this memristive component gives rise to both a previously noted phase-dependent thermal noise, and an undescribed non-stationary, phase-dependent dynamic noise. As experiments are approaching ranges in which these effects may be observed, we examine the form and magnitude of these processes. Their phase dependence can be realized experimentally as a hysteresis effect and may be used to probe defects present in JJ based qubits and in other superconducting electronics applications.

  5. Phonon spectroscopy with superconducting tunnel junctions

    International Nuclear Information System (INIS)

    Grimshaw, J.M.

    1984-02-01

    Superconducting tunnel junctions can be used as generators and detectors of monochromatic phonons of frequency larger than 80 GHz, as was first devised by Eisenmenger and Dayem (1967) and Kinder (1972a, 1973). In this report, we intend to give a general outline of this type of spectroscopy and to present the results obtained so far. The basic physics underlying phonon generation and detection are described in chapter I, a wider approach being given in the references therein. In chapter II, the different types of junctions are considered with respect to their use. Chapter III deals with the evaporation technique for the superconducting junctions. The last part of this report is devoted to the results that we have obtained on γ-irradiated LiF, pure Si and Phosphorous implanted Si. In these chapters, the limitations of the spectrometer are brought out and suggestions for further work are given [fr

  6. Silicon fiber with p-n junction

    International Nuclear Information System (INIS)

    Homa, D.; Cito, A.; Pickrell, G.; Hill, C.; Scott, B.

    2014-01-01

    In this study, we fabricated a p-n junction in a fiber with a phosphorous doped silicon core and fused silica cladding. The fibers were fabricated via a hybrid process of the core-suction and melt-draw techniques and maintained overall diameters ranging from 200 to 900 μm and core diameters of 20–800 μm. The p-n junction was formed by doping the fiber with boron and confirmed via the current-voltage characteristic. The demonstration of a p-n junction in a melt-drawn silicon core fiber paves the way for the seamless integration of optical and electronic devices in fibers.

  7. Tunnel magnetoresistance in double spin filter junctions

    International Nuclear Information System (INIS)

    Saffarzadeh, Alireza

    2003-01-01

    We consider a new type of magnetic tunnel junction, which consists of two ferromagnetic tunnel barriers acting as spin filters (SFs), separated by a nonmagnetic metal (NM) layer. Using the transfer matrix method and the free-electron approximation, the dependence of the tunnel magnetoresistance (TMR) on the thickness of the central NM layer, bias voltage and temperature in the double SF junction are studied theoretically. It is shown that the TMR and electron-spin polarization in this structure can reach very large values under suitable conditions. The highest value of the TMR can reach 99%. By an appropriate choice of the thickness of the central NM layer, the degree of spin polarization in this structure will be higher than that of the single SF junctions. These results may be useful in designing future spin-polarized tunnelling devices

  8. Josephson junctions with ferromagnetic alloy interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Himmel, Nico

    2015-07-23

    Josephson junctions are used as active devices in superconducting electronics and quantum information technology. Outstanding properties are their distinct non-linear electrical characteristics and a usually sinusoidal relation between the current and the superconducting phase difference across the junction. In general the insertion of ferromagnetic material in the barrier of a Josephson junction is associated with a suppression of superconducting correlations. But also new phenomena can arise which may allow new circuit layouts and enhance the performance of applications. This thesis presents a systematic investigation for two concepts to fabricate Josephson junctions with a rather uncommon negative critical current. Such devices exhibit an intrinsic phase slip of π between the electrodes, so they are also known as π junctions. Both studies go well beyond existing experiments and in one system a π junction is shown for the first time. All the thin film junctions are based on superconducting Nb electrodes. In a first approach, barriers made from Si and Fe were investigated with respect to the realisation of π junctions by spin-flip processes. The distribution of Fe in the Si matrix was varied from pure layers to disperse compounds. The systematic fabrication of alloy barriers was facilitated by the development of a novel timing-based combinatorial sputtering technique for planetary deposition systems. An orthogonal gradient approach allowed to create binary layer libraries with independent variations of thickness and composition. Second, Nb vertical stroke AlO{sub x} vertical stroke Nb vertical stroke Ni{sub 60}Cu{sub 40} vertical stroke Nb (SIsFS) double barrier junctions were experimentally studied for the occurrence of proximity effect induced order parameter oscillations. Detailed dependencies of the critical current density on the thickness of s-layer and F-layer were acquired and show a remarkable agreement to existing theoretical predictions. Especially

  9. Electrical analog of a Josephson junction

    International Nuclear Information System (INIS)

    Goldman, A.M.

    1979-01-01

    It is noted that a mathematical description of the phase-coupling of two oscillators synchronized by a phase-lock-loop under the influence of thermal white noise is analogous to that of the phase coupling of two superconductors in a Josephson junction also under the influence of noise. This analogy may be useful in studying threshold instabilities of the Josephson junction in regimes not restricted to the case of large damping. This is of interest because the behavior of the mean voltage near the threshold current can be characterized by critical exponents which resemble those exhibited by an order parameter of a continuous phase transition. As it is possible to couple a collection of oscillators together in a chain, the oscillator analogy may also be useful in exploring the dynamics and statistical mechanics of coupled junctions

  10. Thermionic refrigeration at CNT-CNT junctions

    Science.gov (United States)

    Li, C.; Pipe, K. P.

    2016-10-01

    Monte Carlo (MC) simulation is used to study carrier energy relaxation following thermionic emission at the junction of two van der Waals bonded single-walled carbon nanotubes (SWCNTs). An energy-dependent transmission probability gives rise to energy filtering at the junction, which is predicted to increase the average electron transport energy by as much as 0.115 eV, leading to an effective Seebeck coefficient of 386 μV/K. MC results predict a long energy relaxation length (˜8 μm) for hot electrons crossing the junction into the barrier SWCNT. For SWCNTs of optimal length, an analytical transport model is used to show that thermionic cooling can outweigh parasitic heat conduction due to high SWCNT thermal conductivity, leading to a significant cooling capacity (2.4 × 106 W/cm2).

  11. Josephson junctions with ferromagnetic alloy interlayer

    International Nuclear Information System (INIS)

    Himmel, Nico

    2015-01-01

    Josephson junctions are used as active devices in superconducting electronics and quantum information technology. Outstanding properties are their distinct non-linear electrical characteristics and a usually sinusoidal relation between the current and the superconducting phase difference across the junction. In general the insertion of ferromagnetic material in the barrier of a Josephson junction is associated with a suppression of superconducting correlations. But also new phenomena can arise which may allow new circuit layouts and enhance the performance of applications. This thesis presents a systematic investigation for two concepts to fabricate Josephson junctions with a rather uncommon negative critical current. Such devices exhibit an intrinsic phase slip of π between the electrodes, so they are also known as π junctions. Both studies go well beyond existing experiments and in one system a π junction is shown for the first time. All the thin film junctions are based on superconducting Nb electrodes. In a first approach, barriers made from Si and Fe were investigated with respect to the realisation of π junctions by spin-flip processes. The distribution of Fe in the Si matrix was varied from pure layers to disperse compounds. The systematic fabrication of alloy barriers was facilitated by the development of a novel timing-based combinatorial sputtering technique for planetary deposition systems. An orthogonal gradient approach allowed to create binary layer libraries with independent variations of thickness and composition. Second, Nb vertical stroke AlO x vertical stroke Nb vertical stroke Ni 60 Cu 40 vertical stroke Nb (SIsFS) double barrier junctions were experimentally studied for the occurrence of proximity effect induced order parameter oscillations. Detailed dependencies of the critical current density on the thickness of s-layer and F-layer were acquired and show a remarkable agreement to existing theoretical predictions. Especially a variation of

  12. Mechanically controllable break junctions for molecular electronics.

    Science.gov (United States)

    Xiang, Dong; Jeong, Hyunhak; Lee, Takhee; Mayer, Dirk

    2013-09-20

    A mechanically controllable break junction (MCBJ) represents a fundamental technique for the investigation of molecular electronic junctions, especially for the study of the electronic properties of single molecules. With unique advantages, the MCBJ technique has provided substantial insight into charge transport processes in molecules. In this review, the techniques for sample fabrication, operation and the various applications of MCBJs are introduced and the history, challenges and future of MCBJs are discussed. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Microscopic tunneling theory of long Josephson junctions

    DEFF Research Database (Denmark)

    Grønbech-Jensen, N.; Hattel, Søren A.; Samuelsen, Mogens Rugholm

    1992-01-01

    We present a numerical scheme for solving a nonlinear partial integro-differential equation with nonlocal time dependence. The equation describes the dynamics in a long Josephson junction modeled by use of the microscopic theory for tunneling between superconductors. We demonstrate that the detai......We present a numerical scheme for solving a nonlinear partial integro-differential equation with nonlocal time dependence. The equation describes the dynamics in a long Josephson junction modeled by use of the microscopic theory for tunneling between superconductors. We demonstrate...

  14. Fluctuation of heat current in Josephson junctions

    Directory of Open Access Journals (Sweden)

    P. Virtanen

    2015-02-01

    Full Text Available We discuss the statistics of heat current between two superconductors at different temperatures connected by a generic weak link. As the electronic heat in superconductors is carried by Bogoliubov quasiparticles, the heat transport fluctuations follow the Levitov–Lesovik relation. We identify the energy-dependent quasiparticle transmission probabilities and discuss the resulting probability density and fluctuation relations of the heat current. We consider multichannel junctions, and find that heat transport in diffusive junctions is unique in that its statistics is independent of the phase difference between the superconductors.

  15. Electroplated Ni on the PN Junction Semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Joo; Uhm, Young Rang; Son, Kwang Jae; Kim, Jong Bum; Choi, Sang Moo; Park, Jong Han; Hong, Jintae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Nickel (Ni) electroplating was implemented by using a metal Ni powder in order to establish a Ni-63 plating condition on the PN junction semiconductor needed for production of betavoltaic battery. PN junction semiconductors with a Ni seed layer of 500 and 1000 A were coated with Ni at current density from 10 to 50 mA cm{sup 2}. The surface roughness and average grain size of Ni deposits were investigated by XRD and SEM techniques. The roughness of Ni deposit was increased as the current density was increased, and decreased as the thickness of Ni seed layer was increased.

  16. Electroplated Ni on the PN Junction Semiconductor

    International Nuclear Information System (INIS)

    Kim, Jin Joo; Uhm, Young Rang; Son, Kwang Jae; Kim, Jong Bum; Choi, Sang Moo; Park, Jong Han; Hong, Jintae

    2015-01-01

    Nickel (Ni) electroplating was implemented by using a metal Ni powder in order to establish a Ni-63 plating condition on the PN junction semiconductor needed for production of betavoltaic battery. PN junction semiconductors with a Ni seed layer of 500 and 1000 A were coated with Ni at current density from 10 to 50 mA cm 2 . The surface roughness and average grain size of Ni deposits were investigated by XRD and SEM techniques. The roughness of Ni deposit was increased as the current density was increased, and decreased as the thickness of Ni seed layer was increased

  17. Gap junctions-guards of excitability

    DEFF Research Database (Denmark)

    Stroemlund, Line Waring; Jensen, Christa Funch; Qvortrup, Klaus

    2015-01-01

    Cardiomyocytes are connected by mechanical and electrical junctions located at the intercalated discs (IDs). Although these structures have long been known, it is becoming increasingly clear that their components interact. This review describes the involvement of the ID in electrical disturbances...... of the heart and focuses on the role of the gap junctional protein connexin 43 (Cx43). Current evidence shows that Cx43 plays a crucial role in organizing microtubules at the intercalated disc and thereby regulating the trafficking of the cardiac sodium channel NaV1.5 to the membrane....

  18. Common features of a vortex structure in long exponentially shaped Josephson junctions and Josephson junctions with inhomogeneities

    International Nuclear Information System (INIS)

    Boyadjiev, T.L.; Semerdjieva, E.G.; Shukrinov, Yu.M.

    2007-01-01

    We study the vortex structure in three different models of the long Josephson junction: the exponentially shaped Josephson junction and the Josephson junctions with the resistor and the shunt inhomogeneities in the barrier layer. For these three models the critical curves 'critical current-magnetic field' are numerically constructed. We develop the idea of the equivalence of the exponentially shaped Josephson junction and the rectangular junction with the distributed inhomogeneity and demonstrate that at some parameters of the shunt and the resistor inhomogeneities in the ends of the junction the corresponding critical curves are very close to the exponentially shaped one

  19. Temporo-Parietal Junction Activity in Theory-of-Mind Tasks: Falseness, Beliefs, or Attention

    Science.gov (United States)

    Aichhorn, Markus; Perner, Josef; Weiss, Benjamin; Kronbichler, Martin; Staffen, Wolfgang; Ladurner, Gunther

    2009-01-01

    By combining the false belief (FB) and photo (PH) vignettes to identify theory-of-mind areas with the false sign (FS) vignettes, we re-establish the functional asymmetry between the left and right temporo-parietal junction (TPJ). The right TPJ (TPJ-R) is specially sensitive to processing belief information, whereas the left TPJ (TPJ-L) is equally…

  20. Pronounced Environmental Effects on Injection Currents in EGaln Tunneling Junctions Comprising Self-Assembled Monolayers

    NARCIS (Netherlands)

    Carlotti, Marco; Degen, Maarten; Zhang, Yanxi; Chiechi, Ryan C.

    2016-01-01

    Large-area tunneling junctions using eutectic Ga-In (EGaIn) as a top contact have proven to be a robust, reproducible, and technologically relevant platform for molecular electronics. Thus far, the majority of studies have focused on saturated molecules with backbones consisting mainly of alkanes in

  1. Hydrothermal Exploration at the Chile Triple Junction - ABE's last adventure?

    Science.gov (United States)

    German, C. R.; Shank, T. M.; Lilley, M. D.; Lupton, J. E.; Blackman, D. K.; Brown, K. M.; Baumberger, T.; Früh-Green, G.; Greene, R.; Saito, M. A.; Sylva, S.; Nakamura, K.; Stanway, J.; Yoerger, D. R.; Levin, L. A.; Thurber, A. R.; Sellanes, J.; Mella, M.; Muñoz, J.; Diaz-Naveas, J. L.; Inspire Science Team

    2010-12-01

    In February and March 2010 we conducted preliminary exploration for hydrothermal plume signals along the East Chile Rise where it intersects the continental margin at the Chile Triple Junction (CTJ). This work was conducted as one component of our larger NOAA-OE funded INSPIRE project (Investigation of South Pacific Reducing Environments) aboard RV Melville cruise MV 1003 (PI: Andrew Thurber, Scripps) with all shiptime funded through an award of the State of California to Andrew Thurber and his co-PI's. Additional support came from the Census of Marine Life (ChEss and CoMarge projects). At sea, we conducted a series of CTD-rosette and ABE autonomous underwater vehicle operations to prospect for and determine the nature of any seafloor venting at, or adjacent to, the point where the the East Chile Rise subducts beneath the continental margin. Evidence from in situ sensing (optical backscatter, Eh) and water column analyses of dissolved CH4, δ3He and TDFe/TDMn concentrations document the presence of two discrete sites of venting, one right at the triple junction and the other a further 10km along axis, north of the Triple Junction, but still within the southernmost segment of the East Chile Rise. From an intercomparison of the abundance of different chemical signals we can intercompare likely characteristics of these differet source sites and also differentiate between them and the high methane concentrations released from cold seep sites further north along the Chile Margin, both with the CTJ region and also at the Concepcion Methane Seep Area (CMSA). This multi-disciplinary and international collaboration - involving scientists from Chile, the USA, Europe and Japan - can serve as an excellent and exciting launchpoint for wide-ranging future investigations of the Chile Triple Junction area - the only place on Earth where an oceanic spreading center is being actively subducted beneath a continent and also the only place on Earth where all known forms of deep

  2. Grand Junction health experience from use of uranium tailings in building construction

    International Nuclear Information System (INIS)

    Franz, L.W.

    1980-01-01

    This presentation deals with the possible health effects of the Grand Junction, Colorado exposure situation in which uranium mill tailings were used for building purposes from 1952 to 1966. There are no significant differences between the study group and the control groups with reference to length of residence, to health status prior to diagnosis, or the exposure to tailings location. The excess incidence of leukemia in the Grand Junction area is not explained by this study of proximity to tailings structures. These data neither prove nor disprove the safety of long-term exposure at these low levels of gamma rays

  3. How I do it: surgical ligation of craniocervical junction dural AV fistulas.

    Science.gov (United States)

    Sorenson, Thomas J; La Pira, Biagia; Hughes, Joshua; Lanzino, Giuseppe

    2017-08-01

    Dural arteriovenous fistulas (DAVFs) of the craniocervical junction are uncommon vascular lesions, which often require surgical treatment even in the endovascular era. Most commonly, the fistula is placed laterally, and surgical ligation is performed through a lateral suboccipital craniotomy. After dural opening, the area is inspected, and the arterialized vein is identified emerging from the dura, often adjacent to the entry point of the vertebral artery, and ligated. A far lateral craniotomy is the authors' preferred surgical approach for accessing and treating dural arteriovenous fistulas of the craniocervical junction that cannot be reached endovascularly.

  4. A Monolithic Interconnected module with a tunnel Junction for Enhanced Electrical and Optical Performance

    Energy Technology Data Exchange (ETDEWEB)

    Murray, Christopher Sean; Wilt, David Morgan

    1999-06-30

    An improved thermophotovoltaic (TPV) n/p/n device is provided. Monolithic Interconnected Modules (MIMs), semiconductor devices converting infrared radiation to electricity, have been developed with improved electrical and optical performance. The structure is an n-type emitter on a p-type base with an n-type lateral conduction layer. The incorporation of a tunnel junction and the reduction in the amount of p-type material used results in negligible parasitic absorption, decreased series resistance, increased voltage and increased active area. The novel use of a tunnel junction results in the potential for a TPV device with efficiency greater than 24%.

  5. Scaling Projections on Spin-Transfer Torque Magnetic Tunnel Junctions

    Science.gov (United States)

    Das, Debasis; Tulapurkar, Ashwin; Muralidharan, Bhaskaran

    2018-02-01

    We investigate scaling of technologically relevant magnetic tunnel junction devices in the trilayer and pentalayer configurations by varying the cross-sectional area along the transverse direction using the non-equilibrium Green's function spin transport formalism. We study the geometry dependence by considering square and circular cross-sections. As the transverse dimension in each case reduces, we demonstrate that the transverse mode energy profile plays a major role in the resistance-area product. Both types of devices show constant tunnel magnetoresistance at larger cross-sectional areas but achieve ultra-high magnetoresistance at small cross-sectional areas, while maintaining low resistance-area products. We notice that although the critical switching voltage for switching the magnetization of the free layer nanomagnet in the trilayer case remains constant at larger areas, it needs more energy to switch at smaller areas. In the pentalayer case, we observe an oscillatory behavior at smaller areas as a result of double barrier tunneling. We also describe how switching characteristics of both kinds of devices are affected by the scaling.

  6. Structure modeling and mutational analysis of gap junction beta 2 ...

    African Journals Online (AJOL)

    Yomi

    2012-04-03

    Apr 3, 2012 ... Three dimensional (3 D) structure is very useful for understanding biological functions. Gap junction beta 2 (GJB2), human gene encoding for gap junction beta 2 protein is involved in ... Research in deafness became real.

  7. Systematic optimization of quantum junction colloidal quantum dot solar cells

    KAUST Repository

    Liu, Huan; Zhitomirsky, David; Hoogland, Sjoerd; Tang, Jiang; Kramer, Illan J.; Ning, Zhijun; Sargent, Edward H.

    2012-01-01

    The recently reported quantum junction architecture represents a promising approach to building a rectifying photovoltaic device that employs colloidal quantum dot layers on each side of the p-n junction. Here, we report an optimized quantum

  8. Musical molecules: the molecular junction as an active component in audio distortion circuits

    Science.gov (United States)

    Bergren, Adam Johan; Zeer-Wanklyn, Lucas; Semple, Mitchell; Pekas, Nikola; Szeto, Bryan; McCreery, Richard L.

    2016-03-01

    Molecular junctions that have a non-linear current-voltage characteristic consistent with quantum mechanical tunneling are demonstrated as analog audio clipping elements in overdrive circuits widely used in electronic music, particularly with electric guitars. The performance of large-area molecular junctions fabricated at the wafer level is compared to currently standard semiconductor diode clippers, showing a difference in the sound character. The harmonic distributions resulting from the use of traditional and molecular clipping elements are reported and discussed, and differences in performance are noted that result from the underlying physics that controls the electronic properties of each clipping component. In addition, the ability to tune the sound using the molecular junction is demonstrated. Finally, the hybrid circuit is compared to an overdriven tube amplifier, which has been the standard reference electric guitar clipped tone for over 60 years. In order to investigate the feasibility of manufacturing molecular junctions for use in commercial applications, devices are fabricated using a low-density format at the wafer level, where 38 dies per wafer, each containing two molecular junctions, are made with exceptional non-shorted yield (99.4%, representing 718 out of 722 tested devices) without requiring clean room facilities.

  9. Musical molecules: the molecular junction as an active component in audio distortion circuits

    International Nuclear Information System (INIS)

    Bergren, Adam Johan; Zeer-Wanklyn, Lucas; Pekas, Nikola; Szeto, Bryan; McCreery, Richard L; Semple, Mitchell

    2016-01-01

    Molecular junctions that have a non-linear current–voltage characteristic consistent with quantum mechanical tunneling are demonstrated as analog audio clipping elements in overdrive circuits widely used in electronic music, particularly with electric guitars. The performance of large-area molecular junctions fabricated at the wafer level is compared to currently standard semiconductor diode clippers, showing a difference in the sound character. The harmonic distributions resulting from the use of traditional and molecular clipping elements are reported and discussed, and differences in performance are noted that result from the underlying physics that controls the electronic properties of each clipping component. In addition, the ability to tune the sound using the molecular junction is demonstrated. Finally, the hybrid circuit is compared to an overdriven tube amplifier, which has been the standard reference electric guitar clipped tone for over 60 years. In order to investigate the feasibility of manufacturing molecular junctions for use in commercial applications, devices are fabricated using a low-density format at the wafer level, where 38 dies per wafer, each containing two molecular junctions, are made with exceptional non-shorted yield (99.4%, representing 718 out of 722 tested devices) without requiring clean room facilities. (paper)

  10. Estimating Urban Traffic Patterns through Probabilistic Interconnectivity of Road Network Junctions.

    Directory of Open Access Journals (Sweden)

    Ed Manley

    Full Text Available The emergence of large, fine-grained mobility datasets offers significant opportunities for the development and application of new methodologies for transportation analysis. In this paper, the link between routing behaviour and traffic patterns in urban areas is examined, introducing a method to derive estimates of traffic patterns from a large collection of fine-grained routing data. Using this dataset, the interconnectivity between road network junctions is extracted in the form of a Markov chain. This representation encodes the probability of the successive usage of adjacent road junctions, encoding routes as flows between decision points rather than flows along road segments. This network of functional interactions is then integrated within a modified Markov chain Monte Carlo (MCMC framework, adapted for the estimation of urban traffic patterns. As part of this approach, the data-derived links between major junctions influence the movement of directed random walks executed across the network to model origin-destination journeys. The simulation process yields estimates of traffic distribution across the road network. The paper presents an implementation of the modified MCMC approach for London, United Kingdom, building an MCMC model based on a dataset of nearly 700000 minicab routes. Validation of the approach clarifies how each element of the MCMC framework contributes to junction prediction performance, and finds promising results in relation to the estimation of junction choice and minicab traffic distribution. The paper concludes by summarising the potential for the development and extension of this approach to the wider urban modelling domain.

  11. Sidewall GaAs tunnel junctions fabricated using molecular layer epitaxy

    Directory of Open Access Journals (Sweden)

    Takeo Ohno and Yutaka Oyama

    2012-01-01

    Full Text Available In this article we review the fundamental properties and applications of sidewall GaAs tunnel junctions. Heavily impurity-doped GaAs epitaxial layers were prepared using molecular layer epitaxy (MLE, in which intermittent injections of precursors in ultrahigh vacuum were applied, and sidewall tunnel junctions were fabricated using a combination of device mesa wet etching of the GaAs MLE layer and low-temperature area-selective regrowth. The fabricated tunnel junctions on the GaAs sidewall with normal mesa orientation showed a record peak current density of 35 000 A cm-2. They can potentially be used as terahertz devices such as a tunnel injection transit time effect diode or an ideal static induction transistor.

  12. A cryogenic scanning laser microscope for investigation of dynamical states in long Josephson junctions

    DEFF Research Database (Denmark)

    Holm, Jesper; Mygind, Jesper

    1995-01-01

    on measurements on different oscillator samples, performed with a novel Cryogenic Scanning Laser Microscope (CSLM) having a spatial resolution of less than ±2.5 μm over a 500 μm×50 μm wide scanning area in the temperature range 2 K-300 K. Even though the dynamical states are extremely sensitive to external noise...... tunnel current is one of the most important internal junction parameters which together with the boundary conditions determine the dynamics, it is of vital importance to experimentally determine the current density throughout the entire junction with high spatial resolution. Here we report...... this microscope enables us to make stable in-situ measurements on operating Josephson junctions. Recent results are presented and discussed....

  13. Potential profile and photovoltaic effect in nanoscale lateral pn junction observed by Kelvin probe force microscopy

    International Nuclear Information System (INIS)

    Nowak, Roland; Moraru, Daniel; Mizuno, Takeshi; Jablonski, Ryszard; Tabe, Michiharu

    2014-01-01

    Nanoscale pn junctions have been investigated by Kelvin probe force microscopy and several particular features were found. Within the depletion region, a localized noise area is observed, induced by temporal fluctuations of dopant states. Electronic potential landscape is significantly affected by dopants with ground-state energies deeper than in bulk. Finally, the effects of light illumination were studied and it was found that the depletion region shifts its position as a function of light intensity. This is ascribed to charge redistribution within the pn junction as a result of photovoltaic effect and due to the impact of deepened-level dopants. - Highlights: • In pn nano-junctions, temporal potential fluctuations are found in depletion layer. • Fluctuations are due to frequent capture and emission of free carriers by dopants. • Depletion layer position shifts as a function of the intensity of irradiated light. • The depletion layer shifts are due to changes of deep-level dopants' charge states

  14. Charge-transport in Josephson-junctions with ferromagnetic Ni3Al-interlayer

    International Nuclear Information System (INIS)

    Born, F.

    2006-01-01

    The present dissertation reports on experimental studies about superconducting coupling through a thin Ni 76 Al 24 film. A new patterning process has been developed, which allows in combination with the wedge shaped deposition technique the in situ deposition of 20 single Nb/Al/Al 2 O 3 /Ni 3 Al/Nb multilayers, each with its own well defined Ni 3 Al thickness. Every single multilayer consists of 10 different sized Josephson junctions, showing a high reproducibility and scaling with its junction area. Up to six damped oscillations of the critical current density against F-layer thickness were observed, revealing three single 0-π-transitions in the ground state of Josephson junctions. Contrary to former experimental studies, the exponential decay length is one magnitude larger than the oscillation period defining decay length. The theoretical predictions based on linearised Eilenberger equations results in excellent agreement of theory and experimental results. (orig.)

  15. UMTRA project water sampling and analysis plan, Grand Junction, Colorado

    International Nuclear Information System (INIS)

    1994-07-01

    Surface remedial action will be completed at the Grand Junction processing site during the summer of 1994. Results of 1993 water sampling indicate that ground water flow conditions and ground water quality at the processing site have remained relatively constant with time. Uranium concentrations in ground water continue to exceed the maximum concentration limits, providing the best indication of the extent of contaminated ground water. Evaluation of surface water quality of the Colorado River indicate no impact from uranium processing activities. No compliance monitoring at the Cheney disposal site has been proposed because ground water in the Dakota Sandstone (uppermost aquifer) is classified as limited-use (Class 111) and because the disposal cell is hydrogeologically isolated from the uppermost aquifer. The following water sampling and water level monitoring activities are planned for calendar year 1994: (i) Semiannual (early summer and late fall) sampling of six existing monitor wells at the former Grand Junction processing site. Analytical results from this sampling will be used to continue characterizing hydrogeochemical trends in background ground water quality and in the contaminated ground water area resulting from source term (tailings) removal. (ii) Water level monitoring of approximately three proposed monitor wells projected to be installed in the alluvium at the processing site in September 1994. Data loggers will be installed in these wells, and water levels will be electronically monitored six times a day. These long-term, continuous ground water level data will be collected to better understand the relationship between surface and ground water at the site. Water level and water quality data eventually will be used in future ground water modeling to establish boundary conditions in the vicinity of the Grand Junction processing site. Modeling results will be used to help demonstrate and document the potential remedial alternative of natural flushing

  16. Double-barrier junction based dc SQUID

    NARCIS (Netherlands)

    Bartolomé, M.E.; Brinkman, Alexander; Flokstra, Jakob; Golubov, Alexandre Avraamovitch; Rogalla, Horst

    2000-01-01

    dc SQUIDs based on double-barrier Nb/Al/AlOx/Al/AlOx/Al/Nb junctions (DBSQs) have been fabricated and tested for the first time. The current–voltage curves have been measured at temperatures down to 1.4 K. The critical current, Ic, dependence on the temperature T is partially described by the

  17. Anatomy of the human atrioventricular junctions revisited

    NARCIS (Netherlands)

    Anderson, R. H.; Ho, S. Y.; Becker, A. E.

    2000-01-01

    There have been suggestions made recently that our understanding of the atrioventricular junctions of the heart is less than adequate, with claims for several new findings concerning the arrangement of the ordinary working myocardium and the specialised pathways for atrioventricular conduction. In

  18. CANFLEX fuel bundle junction pressure drop

    International Nuclear Information System (INIS)

    Chung, H. J.; Chung, C. H.; Jun, J. S.; Hong, S. D.; Chang, S. K.; Kim, B. D.

    1996-11-01

    This report describes the junction pressure drop test results which are to used to determine the alignment angle between bundles to achieve the most probable fuel string pressure drop for randomly aligned bundles for use in the fuel string total pressure drop test. (author). 4 tabs., 17 figs

  19. Axial p-n-junctions in nanowires.

    Science.gov (United States)

    Fernandes, C; Shik, A; Byrne, K; Lynall, D; Blumin, M; Saveliev, I; Ruda, H E

    2015-02-27

    The charge distribution and potential profile of p-n-junctions in thin semiconductor nanowires (NWs) were analyzed. The characteristics of screening in one-dimensional systems result in a specific profile with large electric field at the boundary between the n- and p- regions, and long tails with a logarithmic drop in the potential and charge density. As a result of these tails, the junction properties depend sensitively on the geometry of external contacts and its capacity has an anomalously large value and frequency dispersion. In the presence of an external voltage, electrons and holes in the NWs can not be described by constant quasi-Fermi levels, due to small values of the average electric field, mobility, and lifetime of carriers. Thus, instead of the classical Sah-Noice-Shockley theory, the junction current-voltage characteristic was described by an alternative theory suitable for fast generation-recombination and slow diffusion-drift processes. For the non-uniform electric field in the junction, this theory predicts the forward branch of the characteristic to have a non-ideality factor η several times larger than the values 1 < η < 2 from classical theory. Such values of η have been experimentally observed by a number of researchers, as well as in the present work.

  20. Gap junction diseases of the skin.

    NARCIS (Netherlands)

    Steensel, M.A.M. van

    2004-01-01

    Gap junctions are intercellular channels that allow the passage of water, ions, and small molecules. They are involved in quick, short-range messaging between cells and are found in skin, nervous tissue, heart, and muscle. An increasing number of hereditary skin disorders appear to be caused by

  1. Fluxon density waves in long Josephson junctions

    DEFF Research Database (Denmark)

    Olsen, O. H.; Ustinov, A. V.; Pedersen, Niels Falsig

    1993-01-01

    Numerical simulations of the multiple fluxon dynamics stimulated by an external oscillating force applied at a boundary of a long Josephson junction are presented. The calculated IV characteristics agree well with a recent experimental observation of rf-induced satellite flux-flow steps. The volt...... density waves....

  2. Soliton excitations in Josephson tunnel junctions

    DEFF Research Database (Denmark)

    Lomdahl, P. S.; Sørensen, O. H.; Christiansen, Peter Leth

    1982-01-01

    A detailed numerical study of a sine-Gordon model of the Josephson tunnel junction is compared with experimental measurements on junctions with different L / λJ ratios. The soliton picture is found to apply well on both relatively long (L / λJ=6) and intermediate (L / λJ=2) junctions. We find good...... agreement for the current-voltage characteristics, power output, and for the shape and height of the zero-field steps (ZFS). Two distinct modes of soliton oscillations are observed: (i) a bunched or congealed mode giving rise to the fundamental frequency f1 on all ZFS's and (ii) a "symmetric" mode which...... on the Nth ZFS yields the frequency Nf1 Coexistence of two adjacent frequencies is found on the third ZFS of the longer junction (L / λJ=6) in a narrow range of bias current as also found in the experiments. Small asymmetries in the experimental environment, a weak magnetic field, e.g., is introduced via...

  3. Dissipative current in SIFS Josephson junctions

    NARCIS (Netherlands)

    Vasenko, A.; Kawabata, S.; Golubov, Alexandre Avraamovitch; Kupriyanov, M. Yu; Hekking, F.W.J.

    2010-01-01

    We investigate superconductor/insulator/ferromagnet/superconductor (SIFS) tunnel Josephson junctions in the dirty limit, using the quasiclassical theory. We consider the case of a strong tunnel barrier such that the left S layer and the right FS bilayer are decoupled. We calculate quantitatively the

  4. CANFLEX fuel bundle junction pressure drop

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. J.; Chung, C. H.; Jun, J. S.; Hong, S. D.; Chang, S. K.; Kim, B. D.

    1996-11-01

    This report describes the junction pressure drop test results which are to used to determine the alignment angle between bundles to achieve the most probable fuel string pressure drop for randomly aligned bundles for use in the fuel string total pressure drop test. (author). 4 tabs., 17 figs.

  5. The functional anatomy of the ureterovesical junction

    NARCIS (Netherlands)

    Thomson, A. S.; Dabhoiwala, N. F.; Verbeek, F. J.; Lamers, W. H.

    1994-01-01

    To obtain a new insight into the anti-reflux mechanism of the ureterovesical junction by studying the topographical anatomy of the juxta- and intravesical ureter and its relationship to the surrounding bladder musculature. Fresh pig bladders were fixed, frozen and serially sectioned. Enzyme

  6. Critical current of pure SNS junctions

    International Nuclear Information System (INIS)

    Golub, A.A.; Bezzub, O.P.

    1982-01-01

    Boundary conditions at the superconductor-normal metal interface are determined, taking into account the differences in the effective masses and the density of states of the metals constituting the transition and assumed to be pure. The potential barrier of the interface is chosen to be zero. The critical current of the junction is calculated [ru

  7. Improving transition voltage spectroscopy of molecular junctions

    DEFF Research Database (Denmark)

    Markussen, Troels; Chen, Jingzhe; Thygesen, Kristian Sommer

    2011-01-01

    Transition voltage spectroscopy (TVS) is a promising spectroscopic tool for molecular junctions. The principles in TVS is to find the minimum on a Fowler-Nordheim plot where ln(I/V2) is plotted against 1/V and relate the voltage at the minimum Vmin to the closest molecular level. Importantly, Vmin...

  8. Fractional Solitons in Excitonic Josephson Junctions

    Science.gov (United States)

    Su, Jung-Jung; Hsu, Ya-Fen

    The Josephson effect is especially appealing because it reveals macroscopically the quantum order and phase. Here we study this effect in an excitonic Josephson junction: a conjunct of two exciton condensates with a relative phase ϕ0 applied. Such a junction is proposed to take place in the quantum Hall bilayer (QHB) that makes it subtler than in superconductor because of the counterflow of excitonic supercurrent and the interlayer tunneling in QHB. We treat the system theoretically by first mapping it into a pseudospin ferromagnet then describing it by the Landau-Lifshitz-Gilbert equation. In the presence of interlayer tunneling, the excitonic Josephson junction can possess a family of fractional sine-Gordon solitons that resemble the static fractional Josephson vortices in the extended superconducting Josephson junctions. Interestingly, each fractional soliton carries a topological charge Q which is not necessarily a half/full integer but can vary continuously. The resultant current-phase relation (CPR) shows that solitons with Q =ϕ0 / 2 π are the lowest energy states for small ϕ0. When ϕ0 > π , solitons with Q =ϕ0 / 2 π - 1 take place - the polarity of CPR is then switched.

  9. Constructing carbon nanotube junctions by Ar ion beam irradiation

    International Nuclear Information System (INIS)

    Ishaq, Ahmad; Ni Zhichun; Yan Long; Gong Jinlong; Zhu Dezhang

    2010-01-01

    Carbon nanotubes (CNTs) irradiated by Ar ion beams at elevated temperature were studied. The irradiation-induced defects in CNTs are greatly reduced by elevated temperature. Moreover, the two types of CNT junctions, the crossing junction and the parallel junction, were formed. And the CNT networks may be fabricated by the two types of CNT junctions. The formation process and the corresponding mechanism of CNT networks are discussed.

  10. Absolute migration and the evolution of the Rodriguez triple junction ...

    African Journals Online (AJOL)

    The Rodriguez Triple Junction (RTJ) is a junction connecting three mid-ocean ridges in the Indian Ocean: the Southwest Indian Ridge (SWIR), the Central Indian Ridge (CIR) and the Southeast Indian Ridge (SEIR). The evolution of the RTJ has been studied extensively for the past 10 Ma and the triple junction is believed to ...

  11. Junction depth dependence of breakdown in silicon detector diodes

    International Nuclear Information System (INIS)

    Beck, G.A.; Carter, A.A.; Carter, J.R.; Greenwood, N.M.; Lucas, A.D.; Munday, D.J.; Pritchard, T.W.; Robinson, D.; Wilburn, C.D.; Wyllie, K.

    1996-01-01

    The high voltage capability of detector diodes fabricated in the planar process is limited by the high field generated at the edge of the junction.We have fabricated diodes with increased junction depth with respect to our standard process and find a significantly higher breakdown voltage,in reasonable agreement with previous studies of junction breakdown. (orig.)

  12. Long Josephson Junction Stack Coupled to a Cavity

    DEFF Research Database (Denmark)

    Madsen, Søren Peder; Pedersen, Niels Falsig; Groenbech-Jensen, N.

    2007-01-01

    A stack of inductively coupled long Josephson junctions are modeled as a system of coupled sine-Gordon equations. One boundary of the stack is coupled electrically to a resonant cavity. With one fluxon in each Josephson junction, the inter-junction fluxon forces are repulsive. We look at a possible...... transition, induced by the cavity, to a bunched state....

  13. Phenomenological approach to bistable behavior of Josephson junctions

    International Nuclear Information System (INIS)

    Nishi, K.; Nara, S.; Hamanaka, K.

    1985-01-01

    The interaction of unbiased Josephson junction with external electromagnetic field in the presence of externally applied uniform magnetic field is theoretically examined by means of phenomenological treatment. It is proposed that an irradiated junction with suitably chosen parameters shows a bistable behavior of voltage across the junction as a function of the radiation intensity

  14. Systematic study of shallow junction formation on germanium substrates

    DEFF Research Database (Denmark)

    Hellings, Geert; Rosseel, Erik; Clarysse, Trudo

    2011-01-01

    Published results on Ge junctions are benchmarked systematically using RS–XJ plots. The electrical activation level required to meet the ITRS targets is calculated. Additionally, new results are presented on shallow furnace-annealed B junctions and shallow laser-annealed As junctions. Co-implanting...

  15. Intraoperative Assessment of Esophagogastric Junction Distensibility During Laparoscopic Heller Myotomy.

    Science.gov (United States)

    DeHaan, Reece K; Frelich, Matthew J; Gould, Jon C

    2016-04-01

    We sought to characterize the changes in esophagogastric junction (EGJ) distensibility during Heller Myotomy with Dor fundoplication using the EndoFLIP device. Intraoperative distensibility measurements on 14 patients undergoing Heller myotomy with Dor fundoplication were conducted over an 18-month period. Minimum esophageal diameter, cross-sectional areas, and distensibility index were measured at 30 and 40 mL catheter volumes before myotomy, postmyotomy, and following Dor fundoplication. Distensibility index is defined as the narrowest cross-sectional area divided by the corresponding pressure expressed in mm/mm Hg. Heller myotomy was found to lead to significant changes in the distensibility characteristics of the EGJ. Minimum esophageal diameter and EGJ distensibility increased significantly with Heller myotomy.

  16. The Performance of Calcium Silicate Board Partition Fireproof Drywall Assembly with Junction Box under Fire

    Directory of Open Access Journals (Sweden)

    Yinuo Wang

    2015-01-01

    Full Text Available This study uses a metal stud partition fireproof drywall measuring 83 mm in thickness as a test specimen to explore the impact of an embedded junction box on the firefighting performance of the wall through one time of standard fire test on a 300 cm × 300 cm area and five times of standard fire test on a 120 cm × 120 cm area. The results show that the quality of calcium silicate board plays a big role in the fireproof effectiveness. The embedded junction box located on the backside of the fire can reduce the effectiveness of the wall, especially the area above the socket. The thickness of rock wool may increase the performance, but in a limited rate. External junction box may not impact the fireproofing performance of the wall but it still possesses some safety risks. An embedded junction box measuring 101 × 55 mm could already damage the fire compartment, and in reality there may be more complicated situations that should be noted and improved.

  17. Two-dimensional dopant profiling for shallow junctions by TEM and AFM

    International Nuclear Information System (INIS)

    Yoo, K.

    2000-01-01

    The present work concerns the development of the Etch/TEM and Etch/AFM methods to obtain quantitative 2-D dopant profiles for the ultra shallow p-n junctions of the next generation of metal-oxide-semiconductor field effect transistors (MOSFETs). For these methods, thin foil (TEM) or bulk (AFM) cross-sectional specimens were etched using a dopant selective chemical so that local areas of the dopant implanted source/drain (S/D) regions were etched to different depths. The surface topography of the S/D regions was determined from the thickness fringes for the TEM method and by the direct measurement for the AFM method. The local etched depths were converted to etch rates, and these were then converted to corresponding 1-D and 2-D dopant profiles by the experimentally independent etch rate calibration curves. Shallow junction MOSFET samples were designed and fabricated with junction depths 60nm (n + /p), 80nm (n + /p) and 120nm (p + /n) using 0.25μm process technology. A new method using SOG (Spin-on-Glass) contributed to the high quality XTEM thin foil specimens. Controlled stirring of the etchant increased the dopant concentration selectivity and etching consistency. Computer modelling simulated the isotropic etching behaviours, which can introduce the significant error in dopant profiling for shallow and abrupt junction samples. Comprehensive quantitative results enabled the optimum etching time to be determined for the first time. Etch/TEM method gave 1-D dopant profiles that showed good agreement with 1-D Spreading Resistance Probe (SRP) dopant profiles for determining junction depths. 2-D dopant profiles gave L eff , i.e. the shortest lateral distance between the S/D junctions, of major importance for MOSFET performance. Values for L eff of 161, 159 and 123nm were determined from 60, 80 and 120nm junction depth samples respectively, compared with the 215nm MOSFET gate length. The resolution and accuracy of the Etch/TEM method are estimated as 2 and 10nm

  18. The anatomical locus of T-junction processing.

    Science.gov (United States)

    Schirillo, James A

    2009-07-01

    Inhomogeneous surrounds can produce either asymmetrical or symmetrical increment/decrement induction by orienting T-junctions to selectively group a test patch with surrounding regions [Melfi, T., & Schirillo, J. (2000). T-junctions in inhomogeneous surrounds. Vision Research, 40, 3735-3741]. The current experiments aimed to determine where T-junctions are processed by presenting each eye with a different image so that T-junctions exist only in the fused percept. Only minor differences were found between retinal and cortical versus cortical-only conditions, indicating that T-junctions are processed cortically.

  19. Planar Josephson tunnel junctions in a transverse magnetic field

    DEFF Research Database (Denmark)

    Monacoa, R.; Aarøe, Morten; Mygind, Jesper

    2007-01-01

    demagnetization effects imposed by the tunnel barrier and electrodes geometry are important. Measurements of the junction critical current versus magnetic field in planar Nb-based high-quality junctions with different geometry, size, and critical current density show that it is advantageous to use a transverse......Traditionally, since the discovery of the Josephson effect in 1962, the magnetic diffraction pattern of planar Josephson tunnel junctions has been recorded with the field applied in the plane of the junction. Here we discuss the static junction properties in a transverse magnetic field where...

  20. Phase diagrams of particles with dissimilar patches: X-junctions and Y-junctions

    International Nuclear Information System (INIS)

    Tavares, J M; Teixeira, P I C

    2012-01-01

    We use Wertheim’s first-order perturbation theory to investigate the phase behaviour and the structure of coexisting fluid phases for a model of patchy particles with dissimilar patches (two patches of type A and f B patches of type B). A patch of type α = {A,B} can bond to a patch of type β = {A,B} in a volume v αβ , thereby decreasing the internal energy by ε αβ . We analyse the range of model parameters where AB bonds, or Y-junctions, are energetically disfavoured (ε AB AA /2) but entropically favoured (v AB ≫ v αα ), and BB bonds, or X-junctions, are energetically favoured (ε BB > 0). We show that, for low values of ε BB /ε AA , the phase diagram has three different regions: (i) close to the critical temperature a low-density liquid composed of long chains and rich in Y-junctions coexists with a vapour of chains; (ii) at intermediate temperatures there is coexistence between a vapour of short chains and a liquid of very long chains with X- and Y-junctions; (iii) at low temperatures an ideal gas coexists with a high-density liquid with all possible AA and BB bonds formed. It is also shown that in region (i) the liquid binodal is reentrant (its density decreases with decreasing temperature) for the lower values of ε BB /ε AA . The existence of these three regions is a consequence of the competition between the formation of X- and Y-junctions: X-junctions are energetically favoured and thus dominate at low temperatures, whereas Y-junctions are entropically favoured and dominate at higher temperatures. (paper)

  1. Engineering assessment of inactive uranium mill tailings, Grand Junction site, Grand Junction, Colorado. Phase II, Title I

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-10-01

    Ford, Bacon and Davis Utah Inc. has performed an engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, Colorado. The Phase II, Title I services include the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigation of site hydrology and meteorology and the evaluation and costing of alternative corrective actions. Radon gas release from the 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented range from millsite decontamination (Option I), to adding various depths of stabilization cover material (Options II and III), to removal of the tailings to long-term storage sites and decontamination of the present site (Options IV through VIII). Cost estimates for the eight options range from $470,000 to $18,130,000. Reprocessing the tailings for uranium recovery does not appear to be economically attractive at present.

  2. Engineering assessment of inactive uranium mill tailings, Grand Junction site, Grand Junction, Colorado. Phase II, Title I

    International Nuclear Information System (INIS)

    1977-10-01

    Ford, Bacon and Davis Utah Inc. has performed an engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, Colorado. The Phase II, Title I services include the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigation of site hydrology and meteorology and the evaluation and costing of alternative corrective actions. Radon gas release from the 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented range from millsite decontamination (Option I), to adding various depths of stabilization cover material (Options II and III), to removal of the tailings to long-term storage sites and decontamination of the present site (Options IV through VIII). Cost estimates for the eight options range from $470,000 to $18,130,000. Reprocessing the tailings for uranium recovery does not appear to be economically attractive at present

  3. Single-electron tunnel junction array

    International Nuclear Information System (INIS)

    Likharev, K.K.; Bakhvalov, N.S.; Kazacha, G.S.; Serdyukova, S.I.

    1989-01-01

    The authors have carried out an analysis of statics and dynamics of uniform one-dimensional arrays of ultrasmall tunnel junctions. The correlated single-electron tunneling in the junctions of the array results in its behavior qualitatively similar to that of the Josephson transmission line. In particular, external electric fields applied to the array edges can inject single-electron-charged solitons into the array interior. Shape of such soliton and character of its interactions with other solitons and the array edges are very similar to those of the Josephson vortices (sine-Gordon solitons) in the Josephson transmission line. Under certain conditions, a coherent motion of the soliton train along the array is possible, resulting in generation of narrowband SET oscillations with frequency f/sub s/ = /e where is the dc current flowing along the array

  4. Electron transport in doped fullerene molecular junctions

    Science.gov (United States)

    Kaur, Milanpreet; Sawhney, Ravinder Singh; Engles, Derick

    The effect of doping on the electron transport of molecular junctions is analyzed in this paper. The doped fullerene molecules are stringed to two semi-infinite gold electrodes and analyzed at equilibrium and nonequilibrium conditions of these device configurations. The contemplation is done using nonequilibrium Green’s function (NEGF)-density functional theory (DFT) to evaluate its density of states (DOS), transmission coefficient, molecular orbitals, electron density, charge transfer, current, and conductance. We conclude from the elucidated results that Au-C16Li4-Au and Au-C16Ne4-Au devices behave as an ordinary p-n junction diode and a Zener diode, respectively. Moreover, these doped fullerene molecules do not lose their metallic nature when sandwiched between the pair of gold electrodes.

  5. Charge Transport Phenomena in Peptide Molecular Junctions

    International Nuclear Information System (INIS)

    Luchini, A.; Petricoin, E.F.; Geho, D.H.; Liotta, L.A.; Long, D.P.; Vaisman, I.I.

    2008-01-01

    Inelastic electron tunneling spectroscopy (IETS) is a valuable in situ spectroscopic analysis technique that provides a direct portrait of the electron transport properties of a molecular species. In the past, IETS has been applied to small molecules. Using self-assembled nano electronic junctions, IETS was performed for the first time on a large polypeptide protein peptide in the phosphorylated and native form, yielding interpretable spectra. A reproducible 10-fold shift of the I/V characteristics of the peptide was observed upon phosphorylation. Phosphorylation can be utilized as a site-specific modification to alter peptide structure and thereby influence electron transport in peptide molecular junctions. It is envisioned that kinases and phosphatases may be used to create tunable systems for molecular electronics applications, such as biosensors and memory devices.

  6. Electron and Phonon Transport in Molecular Junctions

    DEFF Research Database (Denmark)

    Li, Qian

    Molecular electronics provide the possibility to investigate electron and phonon transport at the smallest imaginable scale, where quantum effects can be investigated and exploited directly in the design. In this thesis, we study both electron transport and phonon transport in molecular junctions....... The system we are interested in here are π-stacked molecules connected with two semi-infinite leads. π-stacked aromatic rings, connected via π-π electronic coupling, provides a rather soft mechanical bridge while maintaining high electronic conductivity. We investigate electron transport...... transmission at the Fermi energy. We propose and analyze a way of using π   stacking to design molecular junctions to control heat transport. We develop a simple model system to identify optimal parameter regimes and then use density functional theory (DFT) to extract model parameters for a number of specific...

  7. Non-Lagrangian theories from brane junctions

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Ling [Chalmers Univ. of Technology, Goeteborg (Sweden); Mitev, Vladimir [Humboldt Univ., Berlin (Germany). Inst. fuer Mathematik und Inst. fuer Physik; Pomoni, Elli [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany). Theory Group; Taki, Masato [RIKEN Nishina Center, Saitama (Japan). Mathematical Physics Lab.; Yagi, Futoshi [International School of Advanced Studies (SISSA), Trieste (Italy); INFN, Trieste (Italy); Korea Institute for Advanced Study (KIAS), Seoul (Korea, Republic of)

    2013-10-15

    In this article we use 5-brane junctions to study the 5D T{sub N} SCFTs corresponding to the 5D N=1 uplift of the 4D N=2 strongly coupled gauge theories, which are obtained by compactifying N M5 branes on a sphere with three full punctures. Even though these theories have no Lagrangian description, by using the 5-brane junctions proposed by Benini, Benvenuti and Tachikawa, we are able to derive their Seiberg-Witten curves and Nekrasov partition functions. We cross-check our results with the 5D superconformal index proposed by Kim, Kim and Lee. Through the AGTW correspondence, we discuss the relations between 5D superconformal indices and n-point functions of the q-deformed W{sub N} Toda theories.

  8. Non-Lagrangian theories from brane junctions

    International Nuclear Information System (INIS)

    Bao, Ling; Mitev, Vladimir

    2013-10-01

    In this article we use 5-brane junctions to study the 5D T N SCFTs corresponding to the 5D N=1 uplift of the 4D N=2 strongly coupled gauge theories, which are obtained by compactifying N M5 branes on a sphere with three full punctures. Even though these theories have no Lagrangian description, by using the 5-brane junctions proposed by Benini, Benvenuti and Tachikawa, we are able to derive their Seiberg-Witten curves and Nekrasov partition functions. We cross-check our results with the 5D superconformal index proposed by Kim, Kim and Lee. Through the AGTW correspondence, we discuss the relations between 5D superconformal indices and n-point functions of the q-deformed W N Toda theories.

  9. Fractional flux quanta in Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    Goldobin, E.; Buckenmaier, K.; Gaber, T.; Kemmler, M.; Pfeiffer, J.; Koelle, D.; Kleiner, R. [Physikalisches Inst. - Experimentalphysik II, Univ. Tuebingen (Germany); Weides, M.; Kohlstedt, H. [Center of Nanoelectronic Systems for Information Technology (CNI), Research Centre Juelich (Germany); Siegel, M. [Inst. fuer Mikro- und Nanoelektronische Systeme, Univ. Karlsruhe (Germany)

    2007-07-01

    Fractional Josephson vortices may appear in the so-called 0-{kappa} Josephson junctions ({kappa} is an arbitrary number) and carry magnetic flux {phi}, which is a fraction of the magnetic flux quantum {phi}{sub 0}{approx}2.07 x 10{sup -15} Wb. Their properties are very different from the usual integer fluxons: they are pinned, and often represent the ground state of the system with spontaneous circulating supercurrent. They behave as well controlled macroscopic spins and can be used to construct bits, qubits, tunable photonic crystals and to study the (quantum) physics of spin systems. In this talk we discuss recent advances in 0-{pi} junction technology and present recent experimental results: evidence of the spontaneous flux in the ground state, spectroscopy of the fractional vortex eigenfrequencies and observation of dynamics effects related to the flipping of the fractional vortices. (orig.)

  10. Relaxation oscillation logic in Josephson junction circuits

    International Nuclear Information System (INIS)

    Fulton, T.A.

    1981-01-01

    A dc powered, self-resetting Josephson junction logic circuit relying on relaxation oscillations is described. A pair of Josephson junction gates are connected in series, a first shunt is connected in parallel with one of the gates, and a second shunt is connected in parallel with the series combination of gates. The resistance of the shunts and the dc bias current bias the gates so that they are capable of undergoing relaxation oscillations. The first shunt forms an output line whereas the second shunt forms a control loop. The bias current is applied to the gates so that, in the quiescent state, the gate in parallel with the second shunt is at V O, and the other gate is undergoing relaxation oscillations. By controlling the state of the first gate with the current in the output loop of another identical circuit, the invert function is performed

  11. Junctional epidermolysis bullosa(non-herlitz type)

    International Nuclear Information System (INIS)

    Bhinder, M. A.; Arshad, M. W.; Shabbir, M. I.; Zahoor, M. Y.; Shehzad, W.; Tariq, M.

    2017-01-01

    Junctional epidermolysis bullosa (JEB) is a recessively inherited skin blistering disease and is caused due to abnormalities in proteins that hold layers of the skin. Herlitz JEB is the severe form and non-Herlitz JEB is the milder form. This report describes a case of congenitally affected male child aged 5 years, with skin blistering. He has mitten-like hands and soft skin blistering on hands, legs and knees. Symptoms almost disappeared at the age of 3 years but reappeared with increased severity after 6 months. Histopathological examination showed epidermal detachment with intact basal cell layer and sparse infiltrate of lymphocytes with few eosinophils in the dermis. There was no blistering on the moist lining of the mouth and digestive tract. Localized symptoms with less lethality and histopathological examination indicated the presence of non-Herlitz type of JEB. This is the first report which confirms the presence of non-Herlitz junctional epidermolysis bullosa in Pakistan. (author)

  12. Junctional Epidermolysis Bullosa (Non-Herlitz Type).

    Science.gov (United States)

    Bhinder, Munir Ahmad; Arshad, Muhammad Waqar; Zahoor, Muhammad Yasir; Shehzad, Wasim; Tariq, Muhammad; Shabbir, Muhammad Imran

    2017-05-01

    Junctional epidermolysis bullosa (JEB) is a recessively inherited skin blistering disease and is caused due to abnormalities in proteins that hold layers of the skin. Herlitz JEB is the severe form and non-Herlitz JEB is the milder form. This report describes a case of congenitally affected male child aged 5 years, with skin blistering. He has mitten-like hands and soft skin blistering on hands, legs and knees. Symptoms almost disappeared at the age of 3 years but reappeared with increased severity after 6 months. Histopathological examination showed epidermal detachment with intact basal cell layer and sparse infiltrate of lymphocytes with few eosinophils in the dermis. There was no blistering on the moist lining of the mouth and digestive tract. Localized symptoms with less lethality and histopathological examination indicated the presence of non-Herlitz type of JEB. This is the first report which confirms the presence of non-Herlitz junctional epidermolysis bullosa in Pakistan.

  13. A novel adhering junction in the apical ciliary apparatus of the rotifer Brachionus plicatilis (Rotifera, Monogononta).

    Science.gov (United States)

    Dallai, R; Lupetti, P; Lane, N J

    1996-10-01

    Cultures of the rotifer Brachionus plicatilis were examined with regard to their interepithelial junctions after infiltration with the extracellular tracer lanthanum, freeze-fracturing or quick-freeze deep-etching. The lateral borders between ciliated cells have an unusual apical adhering junction. This apical part of their intercellular cleft looks desmosome-like, but it is characterized by unusual intramembranous E-face clusters of particles. Deep-etching reveals that these are packed together in short rows which lie parallel to one another in orderly arrays. The true membrane surface in these areas features filaments in the form of short ribbons; these are produced by projections, possibly part of the glycocalyx, emerging from the membranes, between which the electron-dense tracer lanthanum permeates. These projections appear to overlap with each other in the centre of the intercellular cleft; this would provide a particularly flexible adaptation to maintain cell-cell contact and coordination as a consequence. The filamentous ribbons may be held in position by the intramembranous particle arrays since both have a similar size and distribution. These contacts are quite different from desmosomes and appear to represent a distinct new category of adhesive cell-cell junction. Beneath these novel structures, conventional pleated septate junctions are found, exhibiting the undulating intercellular ribbons typical of this junctional type, as well as the usual parallel alignments of intramembranous rows of EF grooves and PF particles. Below these are found gap junctions as close-packed plaques of intramembranous particles on either the P-face or E-face. After freeze-fracturing, the complementary fracture face to the particles shows pits, usually on the P-face, arrayed with a very precise hexagonal pattern.

  14. Defect formation in long Josephson junctions

    DEFF Research Database (Denmark)

    Gordeeva, Anna; Pankratov, Andrey

    2010-01-01

    We study numerically a mechanism of vortex formation in a long Josephson junction within the framework of the one-dimensional sine-Gordon model. This mechanism is switched on below the critical temperature. It is shown that the number of fluxons versus velocity of cooling roughly scales according...... to the power law with the exponent of either 0.25 or 0.5 depending on the temperature variation in the critical current density....

  15. Syringomyelia and Craniocervical Junction Abnormalities in Chihuahuas

    OpenAIRE

    Kiviranta, A.‐M.; Rusbridge, C.; Laitinen‐Vapaavuori, O.; Hielm‐Björkman, A.; Lappalainen, A.K.; Knowler, S.P.; Jokinen, T.S.

    2017-01-01

    Background: Chiari-like malformation (CM) and syringomyelia (SM) are widely reported in Cavalier King Charles Spaniels and Griffon Bruxellois dogs. Increasing evidence indicates that CM and SM also occur in other small and toy breed dogs, such as Chihuahuas. Objectives: To describe the presence of SM and craniocervical junction (CCJ) abnormalities in Chihuahuas and to evaluate the possible association of CCJ abnormalities with SM. To describe CM/SM-related clinical signs and neuro...

  16. Nonlinearity in superconductivity and Josephson junctions

    International Nuclear Information System (INIS)

    Lazarides, N.

    1995-01-01

    Within the framework of the Bardeen, Cooper and Schrieffers (BCS) theory, the influence of anisotropy on superconducting states are investigated. Crystal anisotropy exists in un-conventional low temperature superconductors as e.g. U 1-x Th x Be 13 and in high temperature superconductors. Starting from a phenomenological pairing interaction of the electrons or holes, the BCS approach is used to derive a set of coupled nonlinear algebraic equations for the momentum dependent gap parameter. The emphasis is put on bifurcation phenomena between s-, d-wave and mixed s- and d-wave symmetry and the influence on measurable quantities as the electron specific heat, spin susceptibility and Josephson tunnelling. Pitch-fork and perturbed pitch-fork bifurcations have been found separating s- and d-wave superconducting states from mixed s- and d-wave states. The additional superconducting states give rise to jumps in the electron specific heat below the transition temperature. These jumps are rounded in the case of perturbed pitch-fork bifurcations. An experiment to measure the sign of the interlayer interaction using dc SQUIDS is suggested. The Ambegaokar-Baratoff formalism has been used for calculating the quasiparticle current and the two phase coherent tunnelling currents in a Josephson junction made of anisotropic superconductors. It is shown that anisotropy can lead to a reduction in the product of the normal resistance and the critical current. For low voltages across the junction the usual resistively shunted Josephson model can be used. Finally, bunching in long circular Josephson junctions and suppression of chaos in point junctions have been investigated. (au) 113 refs

  17. Fractional Solitons in Excitonic Josephson Junctions

    OpenAIRE

    Hsu, Ya-Fen; Su, Jung-Jung

    2015-01-01

    The Josephson effect is especially appealing to physicists because it reveals macroscopically the quantum order and phase. In excitonic bilayers the effect is even subtler due to the counterflow of supercurrent as well as the tunneling between layers (interlayer tunneling). Here we study, in a quantum Hall bilayer, the excitonic Josephson junction: a conjunct of two exciton condensates with a relative phase ? 0 applied. The system is mapped into a pseudospin ferromagnet then described numeric...

  18. A semiconductor nanowire Josephson junction microwave laser

    Science.gov (United States)

    Cassidy, Maja; Uilhoorn, Willemijn; Kroll, James; de Jong, Damaz; van Woerkom, David; Nygard, Jesper; Krogstrup, Peter; Kouwenhoven, Leo

    We present measurements of microwave lasing from a single Al/InAs/Al nanowire Josephson junction strongly coupled to a high quality factor superconducting cavity. Application of a DC bias voltage to the Josephson junction results in photon emission into the cavity when the bias voltage is equal to a multiple of the cavity frequency. At large voltage biases, the strong non-linearity of the circuit allows for efficient down conversion of high frequency microwave photons down to multiple photons at the fundamental frequency of the cavity. In this regime, the emission linewidth narrows significantly below the bare cavity linewidth to 50%. The junction-cavity coupling and laser emission can be tuned rapidly via an external gate, making it suitable to be integrated into a scalable qubit architecture as a versatile source of coherent microwave radiation. This work has been supported by the Netherlands Organisation for Scientific Research (NWO/OCW), Foundation for Fundamental Research on Matter (FOM), European Research Council (ERC), and Microsoft Corporation Station Q.

  19. InAs/Si Hetero-Junction Nanotube Tunnel Transistors

    KAUST Repository

    Hanna, Amir; Fahad, Hossain M.; Hussain, Muhammad Mustafa

    2015-01-01

    Hetero-structure tunnel junctions in non-planar gate-all-around nanowire (GAA NW) tunnel FETs (TFETs) have shown significant enhancement in ‘ON’ state tunnel current over their all-silicon counterpart. Here we show the unique concept of nanotube TFET in a hetero-structure configuration that is capable of much higher drive current as opposed to that of GAA NW TFETs.Through the use of inner/outer core-shell gates, a single III-V hetero-structured nanotube TFET leverages physically larger tunneling area while achieving higher driver current (ION) and saving real estates by eliminating arraying requirement. Numerical simulations has shown that a 10 nm thin nanotube TFET with a 100 nm core gate has a 5×normalized output current compared to a 10 nm diameter GAA NW TFET.

  20. InAs/Si Hetero-Junction Nanotube Tunnel Transistors

    KAUST Repository

    Hanna, Amir

    2015-04-29

    Hetero-structure tunnel junctions in non-planar gate-all-around nanowire (GAA NW) tunnel FETs (TFETs) have shown significant enhancement in ‘ON’ state tunnel current over their all-silicon counterpart. Here we show the unique concept of nanotube TFET in a hetero-structure configuration that is capable of much higher drive current as opposed to that of GAA NW TFETs.Through the use of inner/outer core-shell gates, a single III-V hetero-structured nanotube TFET leverages physically larger tunneling area while achieving higher driver current (ION) and saving real estates by eliminating arraying requirement. Numerical simulations has shown that a 10 nm thin nanotube TFET with a 100 nm core gate has a 5×normalized output current compared to a 10 nm diameter GAA NW TFET.

  1. Back-contacted back-junction silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Mangersnes, Krister

    2010-10-15

    have developed a two-dimensional BC-BJ silicon solar cell device model. The simulations, which are based on the finite element method, have been performed with the ATLAS device simulator within the Silvaco simulation framework from Silvaco Inc., USA. The device model has been used to optimize the design of a BC-BJ silicon solar cell based on experimental results obtained during the work with this thesis. The model is able to quantitatively predict the performance of cells with different designs, qualities, and dimensions through optical and electrical simulations, and thereby giving us a good indication of the efficiency potential of the cell structure. It has also given us valuable insight into the physics determining the performance of a BC-BJ silicon solar cell. From this insight, important conclusions regarding the design rules of this type of solar cell devices could be drawn. Finally, the device model was used to investigate quantum mechanical tunneling mechanisms in the junction between the adjacent, highly-doped regions of opposite polarity on the backside of the cell. Through the simulations we found some simple design rules that need to be followed in order to avoid shunting-like behavior due to unwanted trap-assisted tunneling in the lateral tunneling junction. At the same time, band-to-band tunneling entails potential current breakdowns at low to moderate reverse biases. This implies that local hot-spots can be avoided since the heat distribution under reverse bias will be distributed throughout the whole junction area. Thus, by careful optimization and tailoring of the doping profiles, the tunneling may enable the use of back-junction silicon solar cells in a solar module without the need for bypass diodes. (Author)

  2. In vitro early changes in intercellular junctions by treatment with a chemical carcinogen.

    Science.gov (United States)

    Tachikawa, T; Kohno, Y; Matsui, Y; Yoshiki, S

    1986-06-01

    To examine early intercellular junction changes caused by treatment with 9,10-dimethyl-1,2-benzanthracene (DMBA), rat lingual epithelium was cultivated in isolation and observed by electrophysiological, freeze-fracture and whole-mount electron microscopy. Electrophysiological measurements showed a transient decrease in membrane potential of -10.2 mV 6 h after the treatment. It returned to almost the same level as that of the control group 1 day later. Six hours after treatment, input resistance decreased rapidly to 5.3 M omega but increased to 18.0 M omega 12 h after treatment. Transient reduction of input resistance and membrane potential occurred prior to the decrease in the coupling ratio 6 h after treatment with DMBA. In freeze-fracture replicas, the number of gap junctions decreased by approximately 45% of the control value 6 h after treatment with DMBA. At 12 h and thereafter, the number and area of gap junctions subsequently decreased by 60-80% of the control value. Alterations in the number and area of desmosomes were similar to those of the gap junctions. The formation of epithelial cytoskeletons, partially devoid of the 2-4 and 5-8 nm filaments was also observed. A decrease in the density of filament networks beneath the plasma membranes was especially apparent. Treatment with a carcinogen brought about morphological cellular changes as early as 6 h after treatment, and such early changes might trigger metabolic cellular abnormalities. Affected cells appear to move away from normal cells in a process of repeated destruction and revision of intercellular junctions, and cytoskeletons.

  3. Electron Transport through Porphyrin Molecular Junctions

    Science.gov (United States)

    Zhou, Qi

    The goal of this work is to study the properties that would affect the electron transport through a porphyrin molecular junction. This work contributes to the field of electron transport in molecular junctions in the following 3 aspects. First of all, by carrying out experiments comparing the conductance of the iron (III) porphyrin (protected) and the free base porphyrin (protected), it is confirmed that the molecular energy level broadening and shifting occurs for porphyrin molecules when coupled with the metal electrodes, and this level broadening and shifting plays an important role in the electron transport through molecular junctions. Secondly, by carrying out an in-situ deprotection of the acetyl-protected free base porphyrin molecules, it is found out that the presence of acetyl groups reduces the conductance. Thirdly, by incorporating the Matrix-assisted laser desorption/ionization (MALDI) spectrum and the in-situ deprotection prior to formation of molecular junctions, it allows a more precise understanding of the molecules involved in the formation of molecular junctions, and therefore allows an accurate analysis of the conductance histogram. The molecules are prepared by self-assembly and the junctions are formed using a Scanning Tunneling Microscopy (STM) molecular break junction technique. The porphyrin molecules are characterized by MALDI in solution before self-assembly to a gold/mica substrate. The self-assembled monolayers (SAMs) of porphyrins on gold are characterized by Ultraviolet-visible (UV-Vis) reflection spectroscopy to confirm that the molecules are attached to the substrate. The SAMs are then characterized by Angle-Resolved X-ray photoelectron spectroscopy (ARXPS) to determine the thickness and the average molecular orientation of the molecular layer. The electron transport is measured by conductance-displacement (G-S) experiments under a given bias (-0.4V). The conductance value of a single molecule is identified by a statistical analysis

  4. Single P-N junction tandem photovoltaic device

    Science.gov (United States)

    Walukiewicz, Wladyslaw [Kensington, CA; Ager, III, Joel W.; Yu, Kin Man [Lafayette, CA

    2011-10-18

    A single P-N junction solar cell is provided having two depletion regions for charge separation while allowing the electrons and holes to recombine such that the voltages associated with both depletion regions of the solar cell will add together. The single p-n junction solar cell includes an alloy of either InGaN or InAlN formed on one side of the P-N junction with Si formed on the other side in order to produce characteristics of a two junction (2J) tandem solar cell through only a single P-N junction. A single P-N junction solar cell having tandem solar cell characteristics will achieve power conversion efficiencies exceeding 30%.

  5. Electromagnetic waves in single- and multi-Josephson junctions

    International Nuclear Information System (INIS)

    Matsumoto, Hideki; Koyama, Tomio; Machida, Masahiko

    2008-01-01

    The terahertz wave emission from the intrinsic Josephson junctions is one of recent topics in high T c superconductors. We investigate, by numerical simulation, properties of the electromagnetic waves excited by a constant bias current in the single- and multi-Josephson junctions. Nonlinear equations of phase-differences are solved numerically by treating the effects of the outside electromagnetic fields as dynamical boundary conditions. It is shown that the emitted power of the electromagnetic wave can become large near certain retrapping points of the I-V characteristics. An instability of the inside phase oscillation is related to large amplitude of the oscillatory waves. In the single- (or homogeneous mutli-) Josephson junctions, electromagnetic oscillations can occur either in a form of standing waves (shorter junctions) or by formation of vortex-antivortex pairs (longer junctions). How these two effects affects the behavior of electromagnetic waves in the intrinsic Josephson junctions is discussed

  6. Development of a model for Retran-3D for pressure losses at T-junctions

    International Nuclear Information System (INIS)

    Barten, W.; Coddington, P.; Sullivan, J.

    2001-01-01

    For Nuclear Power Plants, both for PWRs and BWRs, there are many instances in normal operation, accidents and transients when it is important to know the pressure drop and quality of the flow, at a flow junction. In this paper two-phase pressure drops in a horizontal T-junction with equal areas are assessed in the case of separating flow using the RETRAN-3D code. Therefore applying the RETRAN-3D code first recoverable pressure drops are calculated for different flow rate ratios, inlet qualities and system pressures for steam-water mixtures. These pressure drops are then compared to analytical expressions by Soliman and Ebadian (1994) developed from the analysis of a wide range of two-phase experimental pressure drop data for equal-sided junctions with horizontal inlet and side branches both for steam-water and air-water flow. With these comparisons the experimental pressure loss is separated into a recoverable part (i.e. that calculated by RETRAN-3D) and an irrecoverable. A model for the irrecoverable pressure losses is derived for the RETRAN-3D code by comparing the RETRAN-3D total momentum equation with the expressions generally used for pressure changes at T-junctions. The results of this model are compared to the experimental data through the expressions of Soliman and Ebadian and are shown to produce very good comparisons particularly for the range of conditions consistent with the experimental data. (author)

  7. Development of a model for Retran-3D for pressure losses at T-junctions

    Energy Technology Data Exchange (ETDEWEB)

    Barten, W.; Coddington, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Sullivan, J. [Penn State University, Nuclear Engineering Program (United States)

    2001-07-01

    For Nuclear Power Plants, both for PWRs and BWRs, there are many instances in normal operation, accidents and transients when it is important to know the pressure drop and quality of the flow, at a flow junction. In this paper two-phase pressure drops in a horizontal T-junction with equal areas are assessed in the case of separating flow using the RETRAN-3D code. Therefore applying the RETRAN-3D code first recoverable pressure drops are calculated for different flow rate ratios, inlet qualities and system pressures for steam-water mixtures. These pressure drops are then compared to analytical expressions by Soliman and Ebadian (1994) developed from the analysis of a wide range of two-phase experimental pressure drop data for equal-sided junctions with horizontal inlet and side branches both for steam-water and air-water flow. With these comparisons the experimental pressure loss is separated into a recoverable part (i.e. that calculated by RETRAN-3D) and an irrecoverable. A model for the irrecoverable pressure losses is derived for the RETRAN-3D code by comparing the RETRAN-3D total momentum equation with the expressions generally used for pressure changes at T-junctions. The results of this model are compared to the experimental data through the expressions of Soliman and Ebadian and are shown to produce very good comparisons particularly for the range of conditions consistent with the experimental data. (author)

  8. Do we really understand the role of the oesophagogastric junction in disease?

    LENUS (Irish Health Repository)

    McMahon, Barry P

    2012-02-01

    The role of the oesophago-gastric junction (OGJ) in gastro-oesophageal reflux disease is still not completely understood, and there is no clinically used method to assess the OGJ function in patients. Only indirect methods such as pH studies are carried out. The OGJ acts a valve controlling the flow of solids, liquids and gases between the oesophagus and the stomach. Manometry can determine if a sphincter is toned or relaxed; but, it cannot confirm that the sphincter region is actually open. Distension is a new technique for measuring function in the OGJ. By measuring the cross-sectional area through the narrow region in the junction during distension of a catheter mounted bag, much more information on the opening and closing patterns of the junction can be determined. This technique has already been demonstrated to show changes in the OGJ after surgical treatments for reflux disease. New measurement ideas around the concept of distending the OGJ offer new hope that a clinically useable test for compliance at the junction can be developed and could potentially help in determining appropriate therapy.

  9. pn junctions based on a single transparent perovskite semiconductor BaSnO3

    Science.gov (United States)

    Kim, Hoon Min; Kim, Useong; Park, Chulkwon; Kwon, Hyukwoo; Lee, Woongjae; Kim, Tai Hoon; Kim, Kee Hoon; Char, Kookrin; Mdpl, Department Of Physics; Astronomy Team; Censcmr, Department Of Physics; Astronomy Team

    2014-03-01

    Successful p doping of transparent oxide semiconductor will further increase its potential, especially in the area of optoelectronic applications. We will report our efforts to dope the BaSnO3 (BSO) with K by pulsed laser deposition. Although the K doped BSO exhibits rather high resistivity at room temperature, its conductivity increases dramatically at higher temperatures. Furthermore, the conductivity decreases when a small amount of oxygen was removed from the film, consistent with the behavior of p type doped oxides. We have fabricated pn junctions by using K doped BSO as a p type and La doped BSO as an n type material. I_V characteristics of these devices show the typical rectifying behavior of pn junctions. We will present the analysis of the junction properties from the temperature dependent measurement of their electrical properties, which shows that the I_V characteristics are consistent with the material parameters such as the carrier concentration, the mobility, and the bandgap. Our demonstration of pn junctions based on a single transparent perovskite semiconductor further enhances the potential of BSO system with high mobility and stability.

  10. Shunted-Josephson-junction model. I. The autonomous case

    DEFF Research Database (Denmark)

    Belykh, V. N.; Pedersen, Niels Falsig; Sørensen, O. H.

    1977-01-01

    The shunted-Josephson-junction model: the parallel combination of a capacitance, a phase-dependent conductance, and an ideal junction element biased by a constant current, is discussed for arbitrary values of the junction parameters. The main objective is to provide a qualitative understanding...... current-voltage curves are presented. The case with a time-dependent monochromatic bias current is treated in a similar fashion in the companion paper....

  11. Magnetic interaction between spatially extended superconducting tunnel junctions

    DEFF Research Database (Denmark)

    Grønbech-Jensen, Niels; Samuelsen, Mogens Rugholm

    2002-01-01

    A general description of magnetic interactions between superconducting tunnel junctions is given. The description covers a wide range of possible experimental systems, and we explicitly explore two experimentally relevant limits of coupled junctions. One is the limit of junctions with tunneling...... been considered through arrays of superconducting weak links based on semiconductor quantum wells with superconducting electrodes. We use the model to make direct interpretations of the published experiments and thereby propose that long-range magnetic interactions are responsible for the reported...

  12. Critical current fluctuation in a microwave-driven Josephson junction

    International Nuclear Information System (INIS)

    Dong Ning; Sun Guozhu; Wang Yiwen; Cao Junyu; Yu Yang; Chen Jian; Kang Lin; Xu Weiwei; Han Siyuan; Wu Peiheng

    2007-01-01

    Josephson junction devices are good candidates for quantum computation. A large energy splitting was observed in the spectroscopy of a superconducting Josephson junction. The presence of the critical current fluctuation near the energy splitting indicated coupling between the junction and a two-level system. Furthermore, we find that this fluctuation is microwave dependent. It only appears at certain microwave frequency. This relation suggested that the decoherence of qubits is influenced by the necessary computing operations

  13. ACCIDENT PREDICTION MODELS FOR UNSIGNALISED URBAN JUNCTIONS IN GHANA

    OpenAIRE

    Mohammed SALIFU, MSc., PhD, MIHT, MGhIE

    2004-01-01

    The main objective of this study was to provide an improved method for safety appraisal in Ghana through the development and application of suitable accident prediction models for unsignalised urban junctions. A case study was designed comprising 91 junctions selected from the two most cosmopolitan cities in Ghana. A wide range of traffic and road data together with the corresponding accident data for each junction for the three-year period 1996-1998 was utilized in the model development p...

  14. Quasiparticle current in superconductor-semiconductor-superconductor junctions

    International Nuclear Information System (INIS)

    Tartakovskij, A.V.; Fistul', M.V.

    1988-01-01

    It is shown that the quasiparticle current in a superconductor-semiconductor-superconductor junction may significantly increase as a result of resonant passage of the quasiparticle along particular trajectories from periodically situated localized centers. A prediction of the theory is that with increasing junction resistance there should be a change from an excessive current to a insufficient current on the current-voltage characteristics (at high voltages). The effect of transparency of the boundaries on resonance tunneling in such junctions is also investigated

  15. Nature of inhomogeneous states in superconducting junctions

    International Nuclear Information System (INIS)

    Ivlev, B.I.; Kopnin, N.B.

    1982-01-01

    A superconducting structure which arises in a superconducting film under a strong injection of a current through a tunnel junction is considered. If the current density in the film exceeds the critical Ginzburg-Landau value, an inhomogeneous resistive state with phase-slip centers can arise in it. This state is charcterized by the presence of regions with different chemical potentials of the Cooper pairs. These shifts of the pair chemical potential and the nonuniform structure of the order parameter may account for the so-called multigap states which have been observed experimentally

  16. Towards ferromagnet/superconductor junctions on graphene

    International Nuclear Information System (INIS)

    Pakkayil, Shijin Babu

    2015-01-01

    Ever since A. Aspect et al. performed the famous 1982 experiment to prove the violation of Bell's inequality, there have been suggestions to conduct the same experiment in a solid state system. Some of those proposals involve superconductors as the source of entangled electron pair and spin depended interfaces as the optical analogue of polariser/filter. Semiconductors can serve as the best medium for such an experiment due to their long relaxation lengths. So far there are no reports on a ferromagnet/superconductor junctions on a semiconductor even though such junctions has been successfully realised in metallic systems. This thesis reports the successful fabrication of ferromagnet/superconductor junction along with characterising measurements in a perfectly two dimensional zero-gap semiconductor known as graphene. Since it's discovery in 2004, graphene has attracted prodigious interest from both academia and industry due to it's inimitable physical properties: very high mobility, high thermal and electrical conductivity, a high Young's modulus and impermeability. Graphene is also expected to have very long spin relaxation length and high spin life time because of it's low spin orbit coupling. For this reason and since researchers are always looking for novel materials and devices to comply with the high demands for better and faster data storage devices, graphene has emanated as a brand new material system for spin based devices. The very first spin injection and detection in graphene was realised in 2007 and ever since, the focal point of the research has been to improve the spin transport properties. A part of this thesis discusses a new fabrication recipe which has a high yield for successfully contacting graphene with a ferromagnet. A high starting yield for ferromagnetic contacts is a irremissible condition for combining superconducting contacts to the device to fabricate ferromagnet/superconductor junctions. Any fabrication recipe

  17. Powered supports for T-junctions

    Energy Technology Data Exchange (ETDEWEB)

    von Klinggraeff, G.; Bohnes, K.

    1981-04-23

    The hydraulic self advancing support system first introduced at Niederberg colliery for a T-junction between a thin seam and a roadway with porch set supports included nearly all components for underpinning the roadway support closest to the face and for supporting the face end close to the roadway, including the rib-side. It ensures a fixed cycle of operations without the need for improvisation while providing continuous strata control during displacement of units. This support combination has proved itself in underground use. As a result, accident incidence was reduced, the number of breakdowns reduced, made the work easier and reduced the number of shifts needed.

  18. Towards ferromagnet/superconductor junctions on graphene

    Energy Technology Data Exchange (ETDEWEB)

    Pakkayil, Shijin Babu

    2015-07-01

    Ever since A. Aspect et al. performed the famous 1982 experiment to prove the violation of Bell's inequality, there have been suggestions to conduct the same experiment in a solid state system. Some of those proposals involve superconductors as the source of entangled electron pair and spin depended interfaces as the optical analogue of polariser/filter. Semiconductors can serve as the best medium for such an experiment due to their long relaxation lengths. So far there are no reports on a ferromagnet/superconductor junctions on a semiconductor even though such junctions has been successfully realised in metallic systems. This thesis reports the successful fabrication of ferromagnet/superconductor junction along with characterising measurements in a perfectly two dimensional zero-gap semiconductor known as graphene. Since it's discovery in 2004, graphene has attracted prodigious interest from both academia and industry due to it's inimitable physical properties: very high mobility, high thermal and electrical conductivity, a high Young's modulus and impermeability. Graphene is also expected to have very long spin relaxation length and high spin life time because of it's low spin orbit coupling. For this reason and since researchers are always looking for novel materials and devices to comply with the high demands for better and faster data storage devices, graphene has emanated as a brand new material system for spin based devices. The very first spin injection and detection in graphene was realised in 2007 and ever since, the focal point of the research has been to improve the spin transport properties. A part of this thesis discusses a new fabrication recipe which has a high yield for successfully contacting graphene with a ferromagnet. A high starting yield for ferromagnetic contacts is a irremissible condition for combining superconducting contacts to the device to fabricate ferromagnet/superconductor junctions. Any fabrication recipe

  19. Gap Junctional Intercellular Communication and Breast Cancer Metastasis to Bone

    National Research Council Canada - National Science Library

    Donahue, Henry

    2001-01-01

    .... We found that: 1) expressing the metastasis suppressing gene BRMS1 in diverse cancer cell lines, including breast and melanoma, restores homotypic gap junctional intercellular communication (GJIC); 2...

  20. On simulation of local fluxes in molecular junctions

    Science.gov (United States)

    Cabra, Gabriel; Jensen, Anders; Galperin, Michael

    2018-05-01

    We present a pedagogical review of the current density simulation in molecular junction models indicating its advantages and deficiencies in analysis of local junction transport characteristics. In particular, we argue that current density is a universal tool which provides more information than traditionally simulated bond currents, especially when discussing inelastic processes. However, current density simulations are sensitive to the choice of basis and electronic structure method. We note that while discussing the local current conservation in junctions, one has to account for the source term caused by the open character of the system and intra-molecular interactions. Our considerations are illustrated with numerical simulations of a benzenedithiol molecular junction.

  1. Spectrum of resonant plasma oscillations in long Josephson junctions

    International Nuclear Information System (INIS)

    Holst, T.

    1996-01-01

    An analysis is presented for the amplitude of the plasma oscillations in the zero-voltage state of a long and narrow Josephson tunnel junction. The calculation is valid for arbitrary normalized junction length and arbitrary bias current. The spectrum of the plasma resonance is found numerically as solutions to an analytical equation. The low-frequency part of the spectrum contains a single resonance, which is known to exist also in the limit of a short and narrow junction. Above a certain cutoff frequency, a series of high-frequency standing wave plasma resonances is excited, a special feature of long Josephson junctions. copyright 1996 The American Physical Society

  2. Several alternative approaches to the manufacturing of HTS Josephson junctions

    OpenAIRE

    Villegier , J.; Boucher , H.; Ghis , A.; Levis , M.; Méchin , Laurence; Moriceau , H.; Pourtier , F.; Vabre , M.; Nicoletti , S.; Correra , L.

    1994-01-01

    In this work we describe comparatively the fabrication and the characterization of various types of HTS Josephson junctions manufactured using different processes : grain boundary junctions have been studied both by the way of junctions on bicrystal substrates and of bi-epitaxial junctions. Ramp-edge types have been elaborated and characterized using mainly N-YBaCuO thin film as a barrier while the trilayer approach has been investigated through a-axis structures. YBaCuO or GdBaCuO supercondu...

  3. ‘Gap Junctions and Cancer: Communicating for 50 Years’

    Science.gov (United States)

    Aasen, Trond; Mesnil, Marc; Naus, Christian C.; Lampe, Paul D.; Laird, Dale W.

    2017-01-01

    Fifty years ago, tumour cells were found to lack electrical coupling, leading to the hypothesis that loss of direct intercellular communication is commonly associated with cancer onset and progression. Subsequent studies linked this phenomenon to gap junctions composed of connexin proteins. While many studies support the notion that connexins are tumour suppressors, recent evidence suggests that, in some tumour types, they may facilitate specific stages of tumour progression through both junctional and non-junctional signalling pathways. This Timeline article highlights the milestones connecting gap junctions to cancer, and underscores important unanswered questions, controversies and therapeutic opportunities in the field. PMID:27782134

  4. Some chaotic features of intrinsically coupled Josephson junctions

    International Nuclear Information System (INIS)

    Kolahchi, M.R.; Shukrinov, Yu.M.; Hamdipour, M.; Botha, A.E.; Suzuki, M.

    2013-01-01

    Highlights: ► Intrinsically coupled Josephson junctions model a high-T c superconductor. ► Intrinsically coupled Josephson junctions can act as a chaotic nonlinear system. ► Chaos could be due to resonance overlap. ► Avoiding parameters that lead to chaos is important for the design of resonators. -- Abstract: We look for chaos in an intrinsically coupled system of Josephson junctions. This study has direct applications for the high-T c resonators which require coherence amongst the junctions

  5. Superconducting Tunnel Junction Arrays for UV Photon Detection, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — An innovative method is described for the fabrication of superconducting tunnel junction (STJ) detector arrays offering true "three dimensional" imaging throughout...

  6. Microwave phase locking of Josephson-junction fluxon oscillators

    DEFF Research Database (Denmark)

    Salerno, M.; Samuelsen, Mogens Rugholm; Filatrella, G.

    1990-01-01

    Application of the classic McLaughlin-Scott soliton perturbation theory to a Josephson-junction fluxon subjected to a microwave field that interacts with the fluxon only at the junction boundaries reduces the problem of phase locking of the fluxon oscillation to the study of a two-dimensional fun......Application of the classic McLaughlin-Scott soliton perturbation theory to a Josephson-junction fluxon subjected to a microwave field that interacts with the fluxon only at the junction boundaries reduces the problem of phase locking of the fluxon oscillation to the study of a two...

  7. Junction Potentials Bias Measurements of Ion Exchange Membrane Permselectivity.

    Science.gov (United States)

    Kingsbury, Ryan S; Flotron, Sophie; Zhu, Shan; Call, Douglas F; Coronell, Orlando

    2018-04-17

    Ion exchange membranes (IEMs) are versatile materials relevant to a variety of water and waste treatment, energy production, and industrial separation processes. The defining characteristic of IEMs is their ability to selectively allow positive or negative ions to permeate, which is referred to as permselectivity. Measured values of permselectivity that equal unity (corresponding to a perfectly selective membrane) or exceed unity (theoretically impossible) have been reported for cation exchange membranes (CEMs). Such nonphysical results call into question our ability to correctly measure this crucial membrane property. Because weighing errors, temperature, and measurement uncertainty have been shown to not explain these anomalous permselectivity results, we hypothesized that a possible explanation are junction potentials that occur at the tips of reference electrodes. In this work, we tested this hypothesis by comparing permselectivity values obtained from bare Ag/AgCl wire electrodes (which have no junction) to values obtained from single-junction reference electrodes containing two different electrolytes. We show that permselectivity values obtained using reference electrodes with junctions were greater than unity for CEMs. In contrast, electrodes without junctions always produced permselectivities lower than unity. Electrodes with junctions also resulted in artificially low permselectivity values for AEMs compared to electrodes without junctions. Thus, we conclude that junctions in reference electrodes introduce two biases into results in the IEM literature: (i) permselectivity values larger than unity for CEMs and (ii) lower permselectivity values for AEMs compared to those for CEMs. These biases can be avoided by using electrodes without a junction.

  8. Effect of junction configurations on microdroplet formation in a T-junction microchannel

    Science.gov (United States)

    Lih, F. L.; Miao, J. M.

    2015-03-01

    This study investigates the dynamic formation process of water microdroplets in a silicon oil flow in a T-junction microchannel. Segmented water microdroplets are formed at the junction when the water flow is perpendicularly injected into the silicon oil flow in a straight rectangular microchannel. This study further presents the effects of the water flow inlet geometry on hydrodynamic characteristics of water microdroplet formation. A numerical multiphase volume of fluid (VOF) scheme is coupled to solve the unsteady three-dimensional laminar Navier-Stokes equations to depict the droplet formation phenomena at the junction. Predicted results on the length and generated frequency of the microdroplets agree well with experimental results in a T-junction microchannel with straight and flat inlets (the base model) for both fluid flows. Empirical correlations are reported between the volumetric flow ratio and the dimensionless microdroplet length or dimensionless frequency of droplet generation at a fixed capillary number of 4.7 · 10-3. The results of this study indicate a reduction in the droplet length of approximately 21% if the straight inlet for the water flow is modified to a downstream sudden contraction inlet for the water flow.

  9. Fabrication of magnetic tunnel junctions with epitaxial and textured ferromagnetic layers

    Science.gov (United States)

    Chang, Y. Austin; Yang, Jianhua Joshua

    2008-11-11

    This invention relates to magnetic tunnel junctions and methods for making the magnetic tunnel junctions. The magnetic tunnel junctions include a tunnel barrier oxide layer sandwiched between two ferromagnetic layers both of which are epitaxial or textured with respect to the underlying substrate upon which the magnetic tunnel junctions are grown. The magnetic tunnel junctions provide improved magnetic properties, sharper interfaces and few defects.

  10. Temperature-sensitive junction transformations for mid-wavelength HgCdTe photovoltaic infrared detector arrays by laser beam induced current microscope

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Weicheng [College of Photoelectric Science and Engineering, National University of Defense Technology, Changsha, Hunan 410073 (China); National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Hu, Weida, E-mail: wdhu@mail.sitp.ac.cn; Lin, Tie; Yin, Fei; Zhang, Bo; Chen, Xiaoshuang; Lu, Wei [National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); Cheng, Xiang' ai, E-mail: xiang-ai-cheng@126.com; Wang, Rui [College of Photoelectric Science and Engineering, National University of Defense Technology, Changsha, Hunan 410073 (China)

    2014-11-10

    In this paper, we report on the disappearance of the photosensitive area extension effect and the unusual temperature dependence of junction transformation for mid-wavelength, n-on-p HgCdTe photovoltaic infrared detector arrays. The n-type region is formed by B{sup +} ion implantation on Hg-vacancy-doped p-type HgCdTe. Junction transformations under different temperatures are visually captured by a laser beam induced current microscope. A physical model of temperature dependence on junction transformation is proposed and demonstrated by using numerical simulations. It is shown that Hg-interstitial diffusion and temperature activated defects jointly lead to the p-n junction transformation dependence on temperature, and the weaker mixed conduction compared with long-wavelength HgCdTe photodiode contributes to the disappearance of the photosensitive area extension effect in mid-wavelength HgCdTe infrared detector arrays.

  11. Behavior of tight-junction, adherens-junction and cell polarity proteins during HNF-4α-induced epithelial polarization

    International Nuclear Information System (INIS)

    Satohisa, Seiro; Chiba, Hideki; Osanai, Makoto; Ohno, Shigeo; Kojima, Takashi; Saito, Tsuyoshi; Sawada, Norimasa

    2005-01-01

    We previously reported that expression of tight-junction molecules occludin, claudin-6 and claudin-7, as well as establishment of epithelial polarity, was triggered in mouse F9 cells expressing hepatocyte nuclear factor (HNF)-4α [H. Chiba, T. Gotoh, T. Kojima, S. Satohisa, K. Kikuchi, M. Osanai, N. Sawada. Hepatocyte nuclear factor (HNF)-4α triggers formation of functional tight junctions and establishment of polarized epithelial morphology in F9 embryonal carcinoma cells, Exp. Cell Res. 286 (2003) 288-297]. Using these cells, we examined in the present study behavior of tight-junction, adherens-junction and cell polarity proteins and elucidated the molecular mechanism behind HNF-4α-initiated junction formation and epithelial polarization. We herein show that not only ZO-1 and ZO-2, but also ZO-3, junctional adhesion molecule (JAM)-B, JAM-C and cell polarity proteins PAR-3, PAR-6 and atypical protein kinase C (aPKC) accumulate at primordial adherens junctions in undifferentiated F9 cells. In contrast, CRB3, Pals1 and PATJ appeared to exhibit distinct subcellular localization in immature cells. Induced expression of HNF-4α led to translocation of these tight-junction and cell polarity proteins to beltlike tight junctions, where occludin, claudin-6 and claudin-7 were assembled, in differentiated cells. Interestingly, PAR-6, aPKC, CRB3 and Pals1, but not PAR-3 or PATJ, were also concentrated on the apical membranes in differentiated cells. These findings indicate that HNF-4α provokes not only expression of tight-junction adhesion molecules, but also modulation of subcellular distribution of junction and cell polarity proteins, resulting in junction formation and epithelial polarization

  12. Optimized electrode configuration for current-in-plane characterization of magnetic tunnel junction stacks

    DEFF Research Database (Denmark)

    Cagliani, Alberto; Kjær, Daniel; Østerberg, Frederik Westergaard

    2017-01-01

    The current-in-plane tunneling technique (CIPT) has been a crucial tool in the development of magnetic tunnel junction stacks suitable for magnetic random access memories (MRAM) for more than a decade. The MRAM development has now reached the maturity to make the transition from the R&D phase...... of electrodes on a multi-electrode probe to reach up to 36% improvement on the repeatability for the resistance area product and the tunneling magnetoresistance measurement, without any hardware modification....

  13. Disruption of the Right Temporoparietal Junction Impairs Probabilistic Belief Updating.

    Science.gov (United States)

    Mengotti, Paola; Dombert, Pascasie L; Fink, Gereon R; Vossel, Simone

    2017-05-31

    Generating and updating probabilistic models of the environment is a fundamental modus operandi of the human brain. Although crucial for various cognitive functions, the neural mechanisms of these inference processes remain to be elucidated. Here, we show the causal involvement of the right temporoparietal junction (rTPJ) in updating probabilistic beliefs and we provide new insights into the chronometry of the process by combining online transcranial magnetic stimulation (TMS) with computational modeling of behavioral responses. Female and male participants performed a modified location-cueing paradigm, where false information about the percentage of cue validity (%CV) was provided in half of the experimental blocks to prompt updating of prior expectations. Online double-pulse TMS over rTPJ 300 ms (but not 50 ms) after target appearance selectively decreased participants' updating of false prior beliefs concerning %CV, reflected in a decreased learning rate of a Rescorla-Wagner model. Online TMS over rTPJ also impacted on participants' explicit beliefs, causing them to overestimate %CV. These results confirm the involvement of rTPJ in updating of probabilistic beliefs, thereby advancing our understanding of this area's function during cognitive processing. SIGNIFICANCE STATEMENT Contemporary views propose that the brain maintains probabilistic models of the world to minimize surprise about sensory inputs. Here, we provide evidence that the right temporoparietal junction (rTPJ) is causally involved in this process. Because neuroimaging has suggested that rTPJ is implicated in divergent cognitive domains, the demonstration of an involvement in updating internal models provides a novel unifying explanation for these findings. We used computational modeling to characterize how participants change their beliefs after new observations. By interfering with rTPJ activity through online transcranial magnetic stimulation, we showed that participants were less able to update

  14. Dynamics of the Josephson multi-junction system with junctions characterized by non-sinusoidal current - phase relationship

    International Nuclear Information System (INIS)

    Abal'osheva, I.; Lewandowski, S.J.

    2004-01-01

    It is shown that the inclusion of junctions characterized by non-sinusoidal current - phase relationship in the systems composed of multiple Josephson junctions - results in the appearance of additional system phase states. Numerical simulations and stability considerations confirm that those phase states can be realized in practice. Moreover, spontaneous formation of the grain boundary junctions in high-T c superconductors with non-trivial current-phase relations due to the d-wave symmetry of the order parameter is probable. Switching between the phase states of multiple grain boundary junction systems can lead to additional 1/f noise in high-T c superconductors. (author)

  15. Theoretical and experimental investigations on synchronization in many-junction arrays of HTSC Josephson junctions. Final report

    International Nuclear Information System (INIS)

    Seidel, P.; Heinz, E.; Pfuch, A.; Machalett, F.; Krech, W.; Basler, M.

    1996-06-01

    Different many-junction arrays of Josephson junctions were studied theoretically to analyse the mechanisms of synchronization, the influence of internal and external parameters and the maximal allowed spread of parameters for the single junctions. Concepts to realize arrays using standard high-T c superconductor technology were created, e.g. the new arrangement of multijunction superconducting loops (MSL). First experimental results show the relevance of this concept. Intrinsic one-dimensional arrays in thin film technology were prepared as mesas out of Bi or Tl 2212 films. to characterize HTSC Josephson junctions methods based on the analysis of microwave-induced steps were developed. (orig.) [de

  16. Y-junction of superconducting Josephson chains

    International Nuclear Information System (INIS)

    Giuliano, Domenico; Sodano, Pasquale

    2009-01-01

    We show that, for pertinent values of the fabrication and control parameters, an attractive finite coupling fixed point emerges in the phase diagram of a Y-junction of superconducting Josephson chains. The new fixed point arises only when the dimensionless flux f piercing the central loop of the network equals π and, thus, does not break time-reversal invariance; for f≠π, only the strongly coupled fixed point survives as a stable attractive fixed point. Phase slips (instantons) have a crucial role in establishing this transition: we show indeed that, at f=π, a new set of instantons-the W-instantons-comes into play to destabilize the strongly coupled fixed point. Finally, we provide a detailed account of the Josephson current-phase relationship along the arms of the network, near each one of the allowed fixed points. Our results evidence remarkable similarities between the phase diagram accessible to a Y-junction of superconducting Josephson chains and the one found in the analysis of quantum Brownian motion on frustrated planar lattices

  17. Edge currents in frustrated Josephson junction ladders

    Science.gov (United States)

    Marques, A. M.; Santos, F. D. R.; Dias, R. G.

    2016-09-01

    We present a numerical study of quasi-1D frustrated Josephson junction ladders with diagonal couplings and open boundary conditions, in the large capacitance limit. We derive a correspondence between the energy of this Josephson junction ladder and the expectation value of the Hamiltonian of an analogous tight-binding model, and show how the overall superconducting state of the chain is equivalent to the minimum energy state of the tight-binding model in the subspace of one-particle states with uniform density. To satisfy the constraint of uniform density, the superconducting state of the ladder is written as a linear combination of the allowed k-states of the tight-binding model with open boundaries. Above a critical value of the parameter t (ratio between the intra-rung and inter-rung Josephson couplings) the ladder spontaneously develops currents at the edges, which spread to the bulk as t is increased until complete coverage is reached. Above a certain value of t, which varies with ladder size (t = 1 for an infinite-sized ladder), the edge currents are destroyed. The value t = 1 corresponds, in the tight-binding model, to the opening of a gap between two bands. We argue that the disappearance of the edge currents with this gap opening is not coincidental, and that this points to a topological origin for these edge current states.

  18. GAP junctional communication in brain secondary organizers.

    Science.gov (United States)

    Bosone, Camilla; Andreu, Abraham; Echevarria, Diego

    2016-06-01

    Gap junctions (GJs) are integral membrane proteins that enable the direct cytoplasmic exchange of ions and low molecular weight metabolites between adjacent cells. They are formed by the apposition of two connexons belonging to adjacent cells. Each connexon is formed by six proteins, named connexins (Cxs). Current evidence suggests that gap junctions play an important part in ensuring normal embryo development. Mutations in connexin genes have been linked to a variety of human diseases, although the precise role and the cell biological mechanisms of their action remain almost unknown. Among the big family of Cxs, several are expressed in nervous tissue but just a few are expressed in the anterior neural tube of vertebrates. Many efforts have been made to elucidate the molecular bases of Cxs cell biology and how they influence the morphogenetic signal activity produced by brain signaling centers. These centers, orchestrated by transcription factors and morphogenes determine the axial patterning of the mammalian brain during its specification and regionalization. The present review revisits the findings of GJ composed by Cx43 and Cx36 in neural tube patterning and discuss Cx43 putative enrollment in the control of Fgf8 signal activity coming from the well known secondary organizer, the isthmic organizer. © 2016 The Authors. Development, Growth & Differentiation published by John Wiley & Sons Australia, Ltd on behalf of Japanese Society of Developmental Biologists.

  19. Electrophysiological study in neuromuscular junction disorders

    Directory of Open Access Journals (Sweden)

    Ajith Cherian

    2013-01-01

    Full Text Available This review is on ultrastructure and subcellular physiology at normal and abnormal neuromuscular junctions. The clinical and electrophysiological findings in myasthenia gravis, Lambert-Eaton myasthenic syndrome (LEMS, congenital myasthenic syndromes, and botulinum intoxication are discussed. Single fiber electromyography (SFEMG helps to explain the basis of testing neuromuscular junction function by repetitive nerve stimulation (RNS. SFEMG requires skill and patience and its availability is limited to a few centers. For RNS supramaximal stimulation is essential and so is display of the whole waveform of each muscle response at maximum amplitude. The amplitudes of the negative phase of the first and fourth responses are measured from baseline to negative peak, and the percent change of the fourth response compared with the first represents the decrement or increment. A decrement greater than 10% is accepted as abnormal and smooth progression of response amplitude train and reproducibility form the crux. In suspected LEMS the effect of fast rates of stimulation should be determined after RNS response to slow rates of stimulation. Caution is required to avoid misinterpretation of potentiation and pseudofacilitation.

  20. Development of superconducting tunnel junction radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Katagiri, Masaki; Kishimoto, Maki; Ukibe, Masahiro; Nakamura, Tatsuya; Nakazawa, Masaharu [Japan Atomic Energy Research Inst., Tokyo (Japan); Kurakado, Masahiko; Ishibashi, Kenji; Maehata, Keisuke

    1998-07-01

    Study on development of high energy resolution X-ray detector using superconducting tunnel junction (STJ) for radiation detection was conducted for 5 years under cooperation of University of Tokyo group and Kyushu University group by Quantum measurement research group of Advanced fundamental research center of JAERI. As the energy resolution of STJ could be obtained better results than that of Si semiconductor detector told to be actually best at present, this study aimed to actualize an X-ray detector usable for the experimental field and to elucidate radiation detection mechanism due to STJ. The STJ element used for this study was the one developed by Kurakado group of Nippon Steel Corp. As a results, some technical problems were almost resolved, which made some trouble when using the STJ element to detection element of X-ray spectrometer. In order to make the X-ray detector better, it is essential to manufacture a STJ element and develop serial junction type STJ element on the base of optimization of the element structure and selection and single crystallization of new superconducting materials such as Ta and others, activating the research results. (G.K.)

  1. Molecular Diffusion through Cyanobacterial Septal Junctions

    Directory of Open Access Journals (Sweden)

    Mercedes Nieves-Morión

    2017-01-01

    Full Text Available Heterocyst-forming cyanobacteria grow as filaments in which intercellular molecular exchange takes place. During the differentiation of N2-fixing heterocysts, regulators are transferred between cells. In the diazotrophic filament, vegetative cells that fix CO2 through oxygenic photosynthesis provide the heterocysts with reduced carbon and heterocysts provide the vegetative cells with fixed nitrogen. Intercellular molecular transfer has been traced with fluorescent markers, including calcein, 5-carboxyfluorescein, and the sucrose analogue esculin, which are observed to move down their concentration gradient. In this work, we used fluorescence recovery after photobleaching (FRAP assays in the model heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 to measure the temperature dependence of intercellular transfer of fluorescent markers. We find that the transfer rate constants are directly proportional to the absolute temperature. This indicates that the “septal junctions” (formerly known as “microplasmodesmata” linking the cells in the filament allow molecular exchange by simple diffusion, without any activated intermediate state. This constitutes a novel mechanism for molecular transfer across the bacterial cytoplasmic membrane, in addition to previously characterized mechanisms for active transport and facilitated diffusion. Cyanobacterial septal junctions are functionally analogous to the gap junctions of metazoans.

  2. Terbinafine inhibits gap junctional intercellular communication

    International Nuclear Information System (INIS)

    Lee, Ju Yeun; Yoon, Sei Mee; Choi, Eun Ju; Lee, Jinu

    2016-01-01

    Terbinafine is an antifungal agent that selectively inhibits fungal sterol synthesis by blocking squalene epoxidase. We evaluated the effect of terbinafine on gap junctional intercellular communication (GJIC). Fluorescence recovery after photobleaching (FRAP) and I-YFP GJIC assays revealed that terbinafine inhibits GJIC in a reversible and dose-dependent manner in FRT-Cx43 and LN215 cells. Treatment with terbinafine did not affect Cx43 phosphorylation status or intracellular Ca 2+ concentration, well-known action mechanisms of various GJIC blockers. While a structurally related chemical, naftifine, attenuated GJIC, epigallocatechin gallate, another potent squalene epoxidase inhibitor with a different structure, did not. These results suggest that terbinafine inhibits GJIC with a so far unknown mechanism of action. - Highlights: • In vitro pharmacological studies were performed on FRT-Cx43 and LN215 cells. • Terbinafine inhibits gap junctional intercellular communication in both cell lines. • The inhibitory effect of terbinafine is reversible and dose-dependent. • Treatment of terbinafine does not alter Cx43 phosphorylation or cytosolic Ca 2+ concentration. • Inhibition of squalene epoxidase is not involved in this new effect of terbinafine.

  3. Dynamics of domain wall networks with junctions

    International Nuclear Information System (INIS)

    Avelino, P. P.; Oliveira, J. C. R. E.; Martins, C. J. A. P.; Menezes, J.; Menezes, R.

    2008-01-01

    We use a combination of analytic tools and an extensive set of the largest and most accurate three-dimensional field theory numerical simulations to study the dynamics of domain wall networks with junctions. We build upon our previous work and consider a class of models which, in the limit of large number N of coupled scalar fields, approaches the so-called ''ideal'' model (in terms of its potential to lead to network frustration). We consider values of N between N=2 and N=20, and a range of cosmological epochs, and we also compare this class of models with other toy models used in the past. In all cases we find compelling evidence for a gradual approach to scaling, strongly supporting our no-frustration conjecture. We also discuss the various possible types of junctions (including cases where there is a hierarchy of them) and their roles in the dynamics of the network. Finally, we provide a cosmological Zel'dovich-type bound on the energy scale of this kind of defect network: it must be lower than 10 keV.

  4. Concept and design of super junction devices

    Science.gov (United States)

    Zhang, Bo; Zhang, Wentong; Qiao, Ming; Zhan, Zhenya; Li, Zhaoji

    2018-02-01

    The super junction (SJ) has been recognized as the " milestone” of the power MOSFET, which is the most important innovation concept of the voltage-sustaining layer (VSL). The basic structure of the SJ is a typical junction-type VSL (J-VSL) with the periodic N and P regions. However, the conventional VSL is a typical resistance-type VSL (R-VSL) with only an N or P region. It is a qualitative change of the VSL from the R-VSL to the J-VSL, introducing the bulk depletion to increase the doping concentration and optimize the bulk electric field of the SJ. This paper firstly summarizes the development of the SJ, and then the optimization theory of the SJ is discussed for both the vertical and the lateral devices, including the non-full depletion mode, the minimum specific on-resistance optimization method and the equivalent substrate model. The SJ concept breaks the conventional " silicon limit” relationship of R on∝V B 2.5, showing a quasi-linear relationship of R on∝V B 1.03.

  5. Virus interaction with the apical junctional complex.

    Science.gov (United States)

    Gonzalez-Mariscal, Lorenza; Garay, Erika; Lechuga, Susana

    2009-01-01

    In order to infect pathogens must breach the epithelial barriers that separate the organism from the external environment or that cover the internal cavities and ducts of the body. Epithelia seal the passage through the paracellular pathway with the apical junctional complex integrated by tight and adherens junctions. In this review we describe how viruses like coxsackie, swine vesicular disease virus, adenovirus, reovirus, feline calcivirus, herpes viruses 1 and 2, pseudorabies, bovine herpes virus 1, poliovirus and hepatitis C use as cellular receptors integral proteins present at the AJC of epithelial cells. Interaction with these proteins contributes in a significant manner in defining the particular tropism of each virus. Besides these proteins, viruses exhibit a wide range of cellular co-receptors among which proteins present in the basolateral cell surface like integrins are often found. Therefore targeting proteins of the AJC constitutes a strategy that might allow viruses to bypass the physical barrier that blocks their access to receptors expressed on the basolateral surface of epithelial cells.

  6. Terbinafine inhibits gap junctional intercellular communication

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ju Yeun, E-mail: whitewndus@naver.com [College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, 85 Songdogwahak-ro, Yeonsu-gu, Incheon 21983 (Korea, Republic of); Yoon, Sei Mee, E-mail: sei_mee@naver.com [College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, 85 Songdogwahak-ro, Yeonsu-gu, Incheon 21983 (Korea, Republic of); Department of Integrated OMICS for Biomedical Sciences, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Choi, Eun Ju, E-mail: yureas@naver.com [College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, 85 Songdogwahak-ro, Yeonsu-gu, Incheon 21983 (Korea, Republic of); Lee, Jinu, E-mail: jinulee@yonsei.ac.kr [College of Pharmacy, Yonsei Institute of Pharmaceutical Sciences, Yonsei University, 85 Songdogwahak-ro, Yeonsu-gu, Incheon 21983 (Korea, Republic of)

    2016-09-15

    Terbinafine is an antifungal agent that selectively inhibits fungal sterol synthesis by blocking squalene epoxidase. We evaluated the effect of terbinafine on gap junctional intercellular communication (GJIC). Fluorescence recovery after photobleaching (FRAP) and I-YFP GJIC assays revealed that terbinafine inhibits GJIC in a reversible and dose-dependent manner in FRT-Cx43 and LN215 cells. Treatment with terbinafine did not affect Cx43 phosphorylation status or intracellular Ca{sup 2+} concentration, well-known action mechanisms of various GJIC blockers. While a structurally related chemical, naftifine, attenuated GJIC, epigallocatechin gallate, another potent squalene epoxidase inhibitor with a different structure, did not. These results suggest that terbinafine inhibits GJIC with a so far unknown mechanism of action. - Highlights: • In vitro pharmacological studies were performed on FRT-Cx43 and LN215 cells. • Terbinafine inhibits gap junctional intercellular communication in both cell lines. • The inhibitory effect of terbinafine is reversible and dose-dependent. • Treatment of terbinafine does not alter Cx43 phosphorylation or cytosolic Ca{sup 2+} concentration. • Inhibition of squalene epoxidase is not involved in this new effect of terbinafine.

  7. Modeling Bloch oscillations in nanoscale Josephson junctions

    Science.gov (United States)

    Vora, Heli; Kautz, R. L.; Nam, S. W.; Aumentado, J.

    2018-01-01

    Bloch oscillations in nanoscale Josephson junctions with a Coulomb charging energy comparable to the Josephson coupling energy are explored within the context of a model previously considered by Geigenmüller and Schön that includes Zener tunneling and treats quasiparticle tunneling as an explicit shot-noise process. The dynamics of the junction quasicharge are investigated numerically using both Monte Carlo and ensemble approaches to calculate voltage-current characteristics in the presence of microwaves. We examine in detail the origin of harmonic and subharmonic Bloch steps at dc biases I = (n/m)2ef induced by microwaves of frequency f and consider the optimum parameters for the observation of harmonic (m = 1) steps. We also demonstrate that the GS model allows a detailed semiquantitative fit to experimental voltage-current characteristics previously obtained at the Chalmers University of Technology, confirming and strengthening the interpretation of the observed microwave-induced steps in terms of Bloch oscillations. PMID:29577106

  8. Stress analysis of PCV nozzle junction

    International Nuclear Information System (INIS)

    Uchiyama, Shoichi; Oikawa, Tsuneo; Hoshino, Seizo

    1976-01-01

    Most of various pressure vessels comprise each one cylindrical shell and one or more nozzles. In this study, in order to analyze the stress in the structures of this type as minutely and exactly as possible, the program for stress analysis by the finite element method was made, which is required for the strength analysis for three-dimensional structures. Especially, the problem of the stress distribution around nozzle junctions was solved theoretically with the program. The program for the analysis developed in this study is provided with various functions, such as the input generator for cylindrical, conical and spherical shells, and plotter, and is very covenient. The accuracy of analysis is very good. The method of analysis and the calculation of the rigidity matrices for the deformation in plane and bending are explained. The result of the stress analysis around the nozzle junctions of a containment vessel with this program was in good agreement with experimental data and the result with SAP-4 code, therefore the propriety of the calculated result with this program was proved. Also calculations were carried out on three cases, namely a flat plate fixed at one end with distributed load, a cylinder fixed at one end with internal pressure, and an I-beam fixed at one end with concentrated load. The calculated results agreed well with theoretical solutions in all cases. (Kako, I.)

  9. Single Molecule Nanoelectrochemistry in Electrical Junctions.

    Science.gov (United States)

    Nichols, Richard J; Higgins, Simon J

    2016-11-15

    It is now possible to reliably measure single molecule conductance in a wide variety of environments including organic liquids, ultrahigh vacuum, water, ionic liquids, and electrolytes. The most commonly used methods deploy scanning probe microscopes, mechanically formed break junctions, or lithographically formed nanogap contacts. Molecules are generally captured between a pair of facing electrodes, and the junction current response is measured as a function of bias voltage. Gating electrodes can also be added so that the electrostatic potential at the molecular bridge can be independently controlled by this third noncontacting electrode. This can also be achieved in an electrolytic environment using a four-electrode bipotentiostatic configuration, which allows independent electrode potential control of the two contacting electrodes. This is commonly realized using an electrochemical STM and enables single molecule electrical characterization as a function of electrode potential and redox state of the molecular bridge. This has emerged as a powerful tool in modern interfacial electrochemistry and nanoelectrochemistry for studying charge transport across single molecules as a function of electrode potential and the electrolytic environments. Such measurements are possible in electrolytes ranging from aqueous buffers to nonaqueous ionic liquids. In this Account, we illustrate a number of examples of single molecule electrical measurements under electrode potential control use a scanning tunneling microscope (STM) and demonstrate how these can help in the understanding of charge transport in single molecule junctions. Examples showing charge transport following phase coherent tunneling to incoherent charge hopping across redox active molecular bridges are shown. In the case of bipyridinium (or viologen) molecular wires, it is shown how electrochemical reduction leads to an increase of the single molecule conductance, which is controlled by the liquid electrochemical

  10. Residence of liquids in the infra-junctional portion of the proximal stomach in patients with gastroesophageal reflux disease

    Directory of Open Access Journals (Sweden)

    Barbieri C.L.A.

    2005-01-01

    Full Text Available Patients with gastroesophageal reflux disease may have disturbances of gastric motility, which could play a role in the pathophysiology of the disease. Recent studies have suggested that the gastric region just below the gastroesophageal junction may have a distinct physiological behavior. We determined whether patients with gastroesophageal reflux disease have abnormal residence of food in the infra-junctional portion of the stomach after ingesting a liquid nutrient meal. Fasted adult patients with reflux disease (N = 11 and healthy volunteers (N = 10 ingested a liquid meal (320 ml; 437 kcal labeled with 99m technetium-phytate and their total gastric emptying half-time and regional emptying from the stomach infra-junctional region were determined. In 8 patients, episodes of postprandial acidic reflux to the esophagus were measured for 2 h using pH monitoring. There were no differences between reflux patients and controls regarding total gastric emptying time (median: 68 min; range: 39-123 min vs 65 min and 60-99 min, respectively; P > 0.50. Food residence in the infra-junctional area was similar for patients and controls: 23% (range: 20-30 vs 27% (range: 19-30%; P = 0.28 and emptying from this area paralleled total gastric emptying (Rs = 0.79; P = 0.04. There was no correlation between residence of food in the infra-junctional area and episodes of gastroesophageal reflux (Rs = 0.06; P = 0.88. We conclude that it is unlikely that regional motor disturbances involving the infra-junctional region of the stomach play a relevant role in the pathogenesis of acidic gastroesophageal reflux.

  11. Josephson junctions in high-T/sub c/ superconductors

    Science.gov (United States)

    Falco, C.M.; Lee, T.W.

    1981-01-14

    The invention includes a high T/sub c/ Josephson sperconducting junction as well as the method and apparatus which provides the junction by application of a closely controlled and monitored electrical discharge to a microbridge region connecting two portions of a superconducting film.

  12. Water and suspended sediment division at a stratified tidal junction

    NARCIS (Netherlands)

    Buschman, F.A.; Vegt, van der M.; Hoitink, A.J.F.; Hoekstra, P.

    2013-01-01

    [1] Tidal junctions play a crucial role in the transport of water, salt, and sediment through a delta distributary network. Water, salt and sediment are exchanged at tidal junctions, thereby influencing the transports in the connecting branches and the overall dynamics of the system. This paper

  13. Shapiro and parametric resonances in coupled Josephson junctions

    International Nuclear Information System (INIS)

    Gaafar, Ma A; Shukrinov, Yu M; Foda, A

    2012-01-01

    The effect of microwave irradiation on the phase dynamics of intrinsic Josephson junctions in high temperature superconductors is investigated. We compare the current-voltage characteristics for a stack of coupled Josephson junctions under external irradiation calculated in the framework of CCJJ and CCJJ+DC models.

  14. Dynamic Control of Tunneling Conductance in Ferroelectric Tunnel Junctions

    International Nuclear Information System (INIS)

    Zou Ya-Yi; Zhou Yan; Chew Khian-Hooi

    2013-01-01

    We investigate the dynamic characteristics of electric polarization P(t) in a ferroelectric junction under ac applied voltage and stress, and calculate the frequency response and the cut-off frequency f 0 , which provides a reference for the upper limit of the working frequency. Our study might be significant for sensor and memory applications of nanodevices based on ferroelectric junctions

  15. Gap junction protein connexin-43 interacts directly with microtubules

    NARCIS (Netherlands)

    Giepmans, B N; Verlaan, I; Hengeveld, T; Janssen, H; Calafat, J; Falk, M M; Moolenaar, W H

    2001-01-01

    Gap junctions are specialized cell-cell junctions that mediate intercellular communication. They are composed of connexin proteins, which form transmembrane channels for small molecules [1, 2]. The C-terminal tail of connexin-43 (Cx43), the most widely expressed connexin member, has been implicated

  16. Water and suspended sediment division at a stratified tidal junction

    NARCIS (Netherlands)

    Buschman, F.A.; Vegt, M. van der; Hoitink, A.J.F.; Hoekstra, P.

    2013-01-01

    Tidal junctions play a crucial role in the transport of water, salt, and sediment through a delta distributary network. Water, salt and sediment are exchanged at tidal junctions, thereby influencing the transports in the connecting branches and the overall dynamics of the system. This paper

  17. 75 FR 76294 - Radio Broadcasting Services: Pacific Junction, IA

    Science.gov (United States)

    2010-12-08

    ... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 [DA 10-2236; MB Docket No. 10-108] Radio Broadcasting Services: Pacific Junction, IA AGENCY: Federal Communications Commission. ACTION: Final rule. SUMMARY: The staff deletes FM Channel 299C2 at Pacific Junction, Iowa, because the record in this...

  18. Vortex dynamics in Josephson ladders with II-junctions

    DEFF Research Database (Denmark)

    Kornev, Victor K.; Klenov, N. V.; Oboznov, V.A.

    2004-01-01

    Both experimental and numerical studies of a self-frustrated triangular array of pi-junctions are reported. The array of SFS Josephson junctions shows a transition to the pi-state and self-frustration with a decrease in temperature. This manifests itself in a half-period shift of the bias critica...

  19. Effect of surface losses on soliton propagation in Josephson junctions

    DEFF Research Database (Denmark)

    Davidson, A.; Pedersen, Niels Falsig; Pagano, S.

    1986-01-01

    We have explored numerically the effects on soliton propagation of a third order damping term in the modified sine-Gordon equation. In Josephson tunnel junctions such a term corresponds physically to quasiparticle losses within the metal electrodes of the junction. We find that this loss term pla...

  20. Preparation of CN /Carbon Nanotube Intramolecular Junctions by ...

    African Journals Online (AJOL)

    NICO

    intramolecular junctions composed of CNx with a bamboo-like structure and empty hollow carbon nanotubes were observed, ... and excellent thermal and mechanical properties.1,2 In recent .... tion of hexane, and the other segment with a curved compart- ... by an arrow lies at the interface of the junction between 'b' and.

  1. Short chain molecular junctions: Charge transport versus dipole moment

    International Nuclear Information System (INIS)

    Ikram, I. Mohamed; Rabinal, M.K.

    2015-01-01

    Graphical abstract: - Highlights: • The role of dipole moment of organic molecules on molecular junctions has been studied. • Molecular junctions constituted using propargyl molecules of different dipole moments. • The electronic properties of the molecules were calculated using Gaussian software. • Junctions show varying rectification due to their varying dipole moment and orientation. - Abstract: The investigation of the influence of dipole moment of short chain organic molecules having three carbon atoms varying in end group on silicon surface was carried on. Here, we use three different molecules of propargyl series varying in dipole moment and its orientation to constitute molecular junctions. The charge transport mechanism in metal–molecules–semiconductor (MMS) junction obtained from current–voltage (I–V) characteristics shows the rectification behavior for two junctions whereas the other junction shows a weak rectification. The electronic properties of the molecules were calculated using Gaussian software package. The observed rectification behavior of these junctions is examined and found to be accounted to the orientation of dipole moment and electron cloud density distribution inside the molecules

  2. Triple junction polymer solar cells for photoelectrochemical water splitting

    NARCIS (Netherlands)

    Esiner, S.; Eersel, van H.; Wienk, M.M.; Janssen, R.A.J.

    2013-01-01

    A triple junction polymer solar cell in a novel 1 + 2 type configuration provides photoelectrochemical water splitting in its maximum power point at V ˜ 1.70 V with an estimated solar to hydrogen energy conversion efficiency of 3.1%. The triple junction cell consists of a wide bandgap front cell and

  3. Manufacturing P-N junctions in germanium bodies

    International Nuclear Information System (INIS)

    Hall, R.N.

    1980-01-01

    A method of producing p-n junctions in Ge so as to facilitate their use as radiation detectors involves forming a body of high purity p-type germanium, diffusing lithium deep into the body, in the absence of electrolytic processes, to form a junction between n-type and p-type germanium greater than 1 mm depth. (UK)

  4. The critical current of point symmetric Josephson tunnel junctions

    International Nuclear Information System (INIS)

    Monaco, Roberto

    2016-01-01

    Highlights: • We disclose some geometrical properties of the critical current field dependence that apply to a large class of Josephson junctions characterized by a point symmetric shape. • The developed theory is valid for any orientation of the applied magnetic field, therefore it allows the determine the consequences of field misalignment in the experimental setups. • We also address that the threshold curves of Josephson tunnel junctions with complex shapes can be expressed as a linear combination of the threshold curves of junctions with simpler point symmetric shapes. - Abstract: The physics of Josephson tunnel junctions drastically depends on their geometrical configurations. The shape of the junction determines the specific form of the magnetic-field dependence of its Josephson current. Here we address the magnetic diffraction patterns of specially shaped planar Josephson tunnel junctions in the presence of an in-plane magnetic field of arbitrary orientations. We focus on a wide ensemble of junctions whose shape is invariant under point reflection. We analyze the implications of this type of isometry and derive the threshold curves of junctions whose shape is the union or the relative complement of two point symmetric plane figures.

  5. Nonlocal Cooper pair splitting in a pSn-junction

    NARCIS (Netherlands)

    Veldhorst, M.; Brinkman, Alexander

    2010-01-01

    Perfect Cooper pair splitting is proposed, based on crossed Andreev reflection (CAR) in a p-type semiconductor-superconductor-n-type semiconductor (pSn) junction. The ideal splitting is caused by the energy filtering that is enforced by the band structure of the electrodes. The pSn junction is

  6. Fast temporal fluctuations in single-molecule junctions.

    Science.gov (United States)

    Ochs, Roif; Secker, Daniel; Elbing, Mark; Mayor, Marcel; Weber, Heiko B

    2006-01-01

    The noise within the electrical current through single-molecule junctions is studied cryogenic temperature. The organic sample molecules were contacted with the mechanically controlled break-junction technique. The noise spectra refer to a where only few Lorentzian fluctuators occur in the conductance. The frequency dependence shows qualitative variations from sample to sample.

  7. Femoroacetabular impingement: bone marrow oedema associated with fibrocystic change of the femoral head and neck junction

    Energy Technology Data Exchange (ETDEWEB)

    James, S.L.J. [Department of Radiology, RNOH Stanmore, Stanmore, Middlesex (United Kingdom) and Department of Radiology, Royal Orthopaedic Hospital, Birmingham (United Kingdom)]. E-mail: jamesslj@email.com; Connell, D.A. [Department of Radiology, RNOH Stanmore, Stanmore, Middlesex (United Kingdom); O' Donnell, P. [Department of Radiology, RNOH Stanmore, Stanmore, Middlesex (United Kingdom); Saifuddin, A. [Department of Radiology, RNOH Stanmore, Stanmore, Middlesex (United Kingdom)

    2007-05-15

    Aim: To describe the association of bone marrow oedema adjacent to areas of fibrocystic change at the femoral head and neck junction in patients with femoroacetabular impingement. Materials and methods: The clinical and imaging findings in six patients with bone marrow oedema adjacent to an area of fibrocystic change at the femoral head and neck junction are presented. There were five males and one female (age range 19-42 years, mean age 34.5 years). Three patients were referred with a clinical suspicion of femoroacetabular impingement, two with suspected osteoid osteoma and one with a clinical diagnosis of sciatica. The volume of bone marrow oedema (grade 1: 0-25%, grade 2: 26-50%, grade 3: 51-75% and grade 4: 76-100% of the femoral neck width), presence of labral and articular cartilage abnormality, joint effusion, and femoral head and neck morphology were recorded. Results: Magnetic resonance imaging (MRI) identified fibrocystic change in the anterolateral aspect of the femoral head and neck junction in all cases (mean size 9 mm, range 5-14 mm, three multilocular and three unilocular cysts). The volume of oedema was variable (one grade 1, two grade 2, one grade 3 and two grade 4). All patients had abnormality of the anterosuperior labrum with five patients demonstrating chondral loss. An abnormal femoral head and neck junction was identified in five patients. Conclusion: The radiological finding of fibrocystic change at the anterosuperior femoral neck with or without bone marrow oedema should prompt the search for femoroacetabular impingement. Bone marrow oedema may rarely be identified adjacent to these areas of cystic change and should be considered in the differential diagnosis of bone marrow oedema in the femoral neck.

  8. Femoroacetabular impingement: bone marrow oedema associated with fibrocystic change of the femoral head and neck junction

    International Nuclear Information System (INIS)

    James, S.L.J.; Connell, D.A.; O'Donnell, P.; Saifuddin, A.

    2007-01-01

    Aim: To describe the association of bone marrow oedema adjacent to areas of fibrocystic change at the femoral head and neck junction in patients with femoroacetabular impingement. Materials and methods: The clinical and imaging findings in six patients with bone marrow oedema adjacent to an area of fibrocystic change at the femoral head and neck junction are presented. There were five males and one female (age range 19-42 years, mean age 34.5 years). Three patients were referred with a clinical suspicion of femoroacetabular impingement, two with suspected osteoid osteoma and one with a clinical diagnosis of sciatica. The volume of bone marrow oedema (grade 1: 0-25%, grade 2: 26-50%, grade 3: 51-75% and grade 4: 76-100% of the femoral neck width), presence of labral and articular cartilage abnormality, joint effusion, and femoral head and neck morphology were recorded. Results: Magnetic resonance imaging (MRI) identified fibrocystic change in the anterolateral aspect of the femoral head and neck junction in all cases (mean size 9 mm, range 5-14 mm, three multilocular and three unilocular cysts). The volume of oedema was variable (one grade 1, two grade 2, one grade 3 and two grade 4). All patients had abnormality of the anterosuperior labrum with five patients demonstrating chondral loss. An abnormal femoral head and neck junction was identified in five patients. Conclusion: The radiological finding of fibrocystic change at the anterosuperior femoral neck with or without bone marrow oedema should prompt the search for femoroacetabular impingement. Bone marrow oedema may rarely be identified adjacent to these areas of cystic change and should be considered in the differential diagnosis of bone marrow oedema in the femoral neck

  9. Shunted-Josephson-junction model. II. The nonautonomous case

    DEFF Research Database (Denmark)

    Belykh, V. N.; Pedersen, Niels Falsig; Sørensen, O. H.

    1977-01-01

    The shunted-Josephson-junction model with a monochromatic ac current drive is discussed employing the qualitative methods of the theory of nonlinear oscillations. As in the preceding paper dealing with the autonomous junction, the model includes a phase-dependent conductance and a shunt capacitance....... The mathematical discussion makes use of the phase-space representation of the solutions to the differential equation. The behavior of the trajectories in phase space is described for different characteristic regions in parameter space and the associated features of the junction IV curve to be expected are pointed...... out. The main objective is to provide a qualitative understanding of the junction behavior, to clarify which kinds of properties may be derived from the shunted-junction model, and to specify the relative arrangement of the important domains in the parameter-space decomposition....

  10. Magnetic field behavior of current steps in long Josephson junctions

    International Nuclear Information System (INIS)

    Costabile, G.; Cucolo, A.M.; Pace, S.; Parmentier, R.D.; Savo, B.; Vaglio, R.

    1980-01-01

    The zero-field steps, or dc current singularities, in the current-voltage characteristics of long Josephson tunnel junctions, first reported by Chen et al., continue to attract research interest both because their study can provide fundamental information on the dynamics of fluxons in such junctions and because they are accompanied by the emission of microwave radiation from the junction, which may be exploitable in practical oscillator applications. The purpose of this paper is to report some experimental observations of the magnetic field behavior of the steps in junctions fabricated in our Laboratory and to offer a qualitative explanation for this behavior. Measurements have been made both for very long (L >> lambdasub(J)) and for slightly long (L approx. >= lambdasub(J)) junctions with a view toward comparing our results with those of other workers. (orig./WRI)

  11. Two coupled Josephson junctions: dc voltage controlled by biharmonic current

    International Nuclear Information System (INIS)

    Machura, L; Spiechowicz, J; Kostur, M; Łuczka, J

    2012-01-01

    We study transport properties of two Josephson junctions coupled by an external shunt resistance. One of the junctions (say, the first) is driven by an unbiased ac current consisting of two harmonics. The device can rectify the ac current yielding a dc voltage across the first junction. For some values of coupling strength, controlled by an external shunt resistance, a dc voltage across the second junction can be generated. By variation of system parameters such as the relative phase or frequency of two harmonics, one can conveniently manipulate both voltages with high efficiency, e.g. changing the dc voltages across the first and second junctions from positive to negative values and vice versa. (paper)

  12. Response of high Tc superconducting Josephson junction to nuclear radiation

    International Nuclear Information System (INIS)

    Ding Honglin; Zhang Wanchang; Zhang Xiufeng

    1992-10-01

    The development of nuclear radiation detectors and research on high T c superconducting nuclear radiation detectors are introduced. The emphases are the principle of using thin-film and thick-film Josephson junctions (bridge junction) based on high T c YBCO superconductors to detect nuclear radiation, the fabrication of thin film and thick-film Josephson junction, and response of junction to low energy gamma-rays of 59.5 keV emitted from 241 Am and beta-rays of 546 keV. The results show that a detector for measuring nuclear radiation spectrum made of high T c superconducting thin-film or thick-film, especially, thick-film Josephson junction, certainly can be developed

  13. Spatially resolved detection of mutually locked Josephson junctions in arrays

    International Nuclear Information System (INIS)

    Keck, M.; Doderer, T.; Huebener, R.P.; Traeuble, T.; Dolata, R.; Weimann, T.; Niemeyer, J.

    1997-01-01

    Mutual locking due to the internal coupling in two-dimensional arrays of Josephson junctions was investigated. The appearance of Shapiro steps in the current versus voltage curve of a coupled on-chip detector junction is used to indicate coherent oscillations in the array. A highly coherent state is observed for some range of the array bias current. By scanning the array with a low-power electron beam, mutually locked junctions remain locked while the unlocked junctions generate a beam-induced additional voltage drop at the array. This imaging technique allows the detection of the nonlocked or weakly locked Josephson junctions in a (partially) locked array state. copyright 1997 American Institute of Physics

  14. Scattering theory of superconductive tunneling in quantum junctions

    International Nuclear Information System (INIS)

    Shumeiko, V.S.; Bratus', E.N.

    1997-01-01

    A consistent theory of superconductive tunneling in single-mode junctions within a scattering formulation of Bogolyubov-de Gennes quantum mechanics is presented. The dc Josephson effect and dc quasiparticle transport in the voltage-biased junctions are considered. Elastic quasiparticle scattering by the junction determines the equilibrium Josephson current. The origin of Andreev bound states in tunnel junctions and their role in equilibrium Josephson transport are discussed. In contrast, quasiparticle tunneling in voltage-biased junctions is determined by inelastic scattering. A general expression for inelastic scattering amplitudes is derived and the quasiparticle current is calculated at all voltages with emphasis on a discussion of the properties of sub gap tunnel current and the nature of subharmonic gap structure

  15. Functional Molecular Junctions Derived from Double Self-Assembled Monolayers.

    Science.gov (United States)

    Seo, Sohyeon; Hwang, Eunhee; Cho, Yunhee; Lee, Junghyun; Lee, Hyoyoung

    2017-09-25

    Information processing using molecular junctions is becoming more important as devices are miniaturized to the nanoscale. Herein, we report functional molecular junctions derived from double self-assembled monolayers (SAMs) intercalated between soft graphene electrodes. Newly assembled molecular junctions are fabricated by placing a molecular SAM/(top) electrode on another molecular SAM/(bottom) electrode by using a contact-assembly technique. Double SAMs can provide tunneling conjugation across the van der Waals gap between the terminals of each monolayer and exhibit new electrical functions. Robust contact-assembled molecular junctions can act as platforms for the development of equivalent contact molecular junctions between top and bottom electrodes, which can be applied independently to different kinds of molecules to enhance either the structural complexity or the assembly properties of molecules. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Surface-Enhanced Raman Scattering in Molecular Junctions.

    Science.gov (United States)

    Iwane, Madoka; Fujii, Shintaro; Kiguchi, Manabu

    2017-08-18

    Surface-enhanced Raman scattering (SERS) is a surface-sensitive vibrational spectroscopy that allows Raman spectroscopy on a single molecular scale. Here, we present a review of SERS from molecular junctions, in which a single molecule or molecules are made to have contact from the top to the bottom of metal surfaces. The molecular junctions are nice platforms for SERS as well as transport measurement. Electronic characterization based on the transport measurements of molecular junctions has been extensively studied for the development of miniaturized electronic devices. Simultaneous SERS and transport measurement of the molecular junctions allow both structural (geometrical) and electronic information on the single molecule scale. The improvement of SERS measurement on molecular junctions open the door toward new nanoscience and nanotechnology in molecular electronics.

  17. Observation of supercurrent in graphene-based Josephson junction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Libin; Li, Sen; Kang, Ning [Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, Beijing 100871 (China); Xu, Chuan; Ren, Wencai [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China)

    2015-07-01

    Josephson junctions with a normal metal region sandwiched between two superconductors (S) are known as superconductor- normal-superconductor (SNS) structures. It has attracted significant attention especially when changing the normal metal with graphene, which allow for high tunability with the gate voltage and to study the proximity effect of the massless Dirac fermions. Here we report our work on graphene-based Josephson junction with a new two dimensional superconductor crystal, which grown directly on graphene, as superconducting electrodes. At low temperature, we observer proximity effect induced supercurrent flowing through the junction. The temperature and the magnetic field dependences of the critical current characteristics of the junction are also studied. The critical current exhibits a Fraunhofer-type diffraction pattern against magnetic field. Our experiments provided a new route of fabrication of graphene-based Josephson junction.

  18. Evidence for a continental unstable triple junction as an alternate model for Vrancea seismicity

    International Nuclear Information System (INIS)

    Besutiu, L.

    2002-01-01

    The Vrancea active seismic zone located in the bending area of Romanian Carpathians stands for a long time as a challenge to geoscientists all over the world. Deep seismicity in continental collision circumstances is rather rare and always constraints on dynamics of subduction. The pattern of the intermediate-depth seismicity in the Vrancea region suggests a confined prismatic nearly vertical seismic body. The small size and geometry of the seismic zone have made it difficult to interpret the kinematics of subduction and continental collision in the area. During the years, several models, almost all subduction-related, have more or less successfully tried to explain this phenomenon. The paper represents an attempt to explain the Vrancea intermediate depth seismicity starting from a new concept, as introduced by the plate tectonics theory: the triple junction. A continental unstable triple junction is proposed as an alternate model to explain the unusual seismicity in the Vrancea seismic area. Three tectonic plates / microplates seem to join in the region: East European Plate (EEP), Moesian microplate (MoP), and the Intra-Alpine microplate (IaP). Their edges are geophysically documented and their motion is evidenced. The differentiation in their relative velocities generated an unstable transform-transform-compression triple junction that determined the vertical collapse of the lithospheric segment to which the intermediate seismicity within Vrancea zone is associated. Three major plates' wedges bound the seismic body: Tornquist-Teissyere zone, Peceneaga-Camena fault, and Trans-Getica fault. Temperature accommodation phenomena associated to the sinking lithospheric body into the hotter upper mantle environment (such as convective cells, phase-transform processes, and devolatilization) could be responsible for the earthquakes occurrence. The problem of the missing subduction related volcanism within Vrancea triple junction (VTJ) area is definitely solved in the case

  19. Fabrication-process-induced variations of Nb/Al/AlOx/Nb Josephson junctions in superconductor integrated circuits

    International Nuclear Information System (INIS)

    Tolpygo, Sergey K; Amparo, Denis

    2010-01-01

    Currently, superconductor digital integrated circuits fabricated at HYPRES, Inc. can operate at clock frequencies approaching 40 GHz. The circuits present multilayered structures containing tens of thousands of Nb/Al/AlO x /Nb Josephson junctions (JJs) of various sizes interconnected by four Nb wiring layers, resistors, and other circuit elements. In order to be fully operational, the integrated circuits should be fabricated such that the critical currents of the JJs are within the tight design margins and the proper relationships between the critical currents of JJs of different sizes are preserved. We present experimental data and discuss mechanisms of process-induced variations of the critical current and energy gap of Nb/Al/AlO x /Nb JJs in integrated circuits. We demonstrate that the Josephson critical current may depend on the type and area of circuit elements connected to the junction, on the circuit pattern, and on the step in the fabrication process at which the connection is made. In particular, we discuss the influence of (a) the junction base electrode connection to the ground plane, (b) the junction counter electrode connection to the ground plane, and (c) the counter electrode connection to the Ti/Au or Ti/Pd/Au contact pads by Nb wiring. We show that the process-induced changes of the properties of Nb/Al/AlO x /Nb junctions are caused by migration of impurity atoms (hydrogen) between the different layers comprising the integrated circuits.

  20. Microstructure of Josephson junctions: Effect on supercurrent transport in YBCO grain boundary and barrier layer junctions

    International Nuclear Information System (INIS)

    Merkle, K.L.; Huang, Y.

    1998-01-01

    The electric transport of high-temperature superconductors, such as YBa 2 Cu 3 O 7-x (YBCO), can be strongly restricted by the presence of high-angle grain boundaries (GB). This weak-link behavior is governed by the macroscopic GB geometry and the microscopic grain boundary structure and composition at the atomic level. Whereas grain boundaries present a considerable impediment to high current applications of high T c materials, there is considerable commercial interest in exploiting the weak-link-nature of grain boundaries for the design of microelectronic devices, such as superconducting quantum interference devices (SQUIDs). The Josephson junctions which form the basis of this technology can also be formed by introducing artificial barriers into the superconductor. The authors have examined both types of Josephson junctions by EM techniques in an effort to understand the connection between microstructure/chemistry and electrical transport properties. This knowledge is a valuable resource for the design and production of improved devices

  1. RF assisted switching in magnetic Josephson junctions

    Science.gov (United States)

    Caruso, R.; Massarotti, D.; Bolginov, V. V.; Ben Hamida, A.; Karelina, L. N.; Miano, A.; Vernik, I. V.; Tafuri, F.; Ryazanov, V. V.; Mukhanov, O. A.; Pepe, G. P.

    2018-04-01

    We test the effect of an external RF field on the switching processes of magnetic Josephson junctions (MJJs) suitable for the realization of fast, scalable cryogenic memories compatible with Single Flux Quantum logic. We show that the combined application of microwaves and magnetic field pulses can improve the performances of the device, increasing the separation between the critical current levels corresponding to logical "0" and "1." The enhancement of the current level separation can be as high as 80% using an optimal set of parameters. We demonstrate that external RF fields can be used as an additional tool to manipulate the memory states, and we expect that this approach may lead to the development of new methods of selecting MJJs and manipulating their states in memory arrays for various applications.

  2. Ultimately short ballistic vertical graphene Josephson junctions

    Science.gov (United States)

    Lee, Gil-Ho; Kim, Sol; Jhi, Seung-Hoon; Lee, Hu-Jong

    2015-01-01

    Much efforts have been made for the realization of hybrid Josephson junctions incorporating various materials for the fundamental studies of exotic physical phenomena as well as the applications to superconducting quantum devices. Nonetheless, the efforts have been hindered by the diffusive nature of the conducting channels and interfaces. To overcome the obstacles, we vertically sandwiched a cleaved graphene monoatomic layer as the normal-conducting spacer between superconducting electrodes. The atomically thin single-crystalline graphene layer serves as an ultimately short conducting channel, with highly transparent interfaces with superconductors. In particular, we show the strong Josephson coupling reaching the theoretical limit, the convex-shaped temperature dependence of the Josephson critical current and the exceptionally skewed phase dependence of the Josephson current; all demonstrate the bona fide short and ballistic Josephson nature. This vertical stacking scheme for extremely thin transparent spacers would open a new pathway for exploring the exotic coherence phenomena occurring on an atomic scale. PMID:25635386

  3. Quasiparticle dynamics in superconducting tunnel junctions

    International Nuclear Information System (INIS)

    Kozorezov, A.G.; Brammertz, G.; Hijmering, R.A.; Wigmore, J.K.; Peacock, A.; Martin, D.; Verhoeve, P.; Golubov, A.A.; Rogalla, H.

    2006-01-01

    Superconducting Tunnel Junctions (STJs) used as single photon detectors possess extreme sensitivity and excellent resolving power. However, like many other cryogenic detectors they operate under extremely non-equilibrium conditions. In order to understand the physics of the non-equilibrium, non-stationary state, to interpret experimental data adequately, and to optimize the STJs unique performance, it is necessary to use a fully kinetic approach. We have developed the detailed theory of interactions between quasiparticles (qps) and the two types of phonons, sub-gap and pair-breaking, in STJ photon detectors. We discuss the results of extensive sets of experiments to study the non-equilibrium state in Al-based STJs. For the first time we are capable of explaining all available data systematically using a single set of parameters determined from STJ diagnostics and independent experiments

  4. Field-effect P-N junction

    Science.gov (United States)

    Regan, William; Zettl, Alexander

    2015-05-05

    This disclosure provides systems, methods, and apparatus related to field-effect p-n junctions. In one aspect, a device includes an ohmic contact, a semiconductor layer disposed on the ohmic contact, at least one rectifying contact disposed on the semiconductor layer, a gate including a layer disposed on the at least one rectifying contact and the semiconductor layer and a gate contact disposed on the layer. A lateral width of the rectifying contact is less than a semiconductor depletion width of the semiconductor layer. The gate contact is electrically connected to the ohmic contact to create a self-gating feedback loop that is configured to maintain a gate electric field of the gate.

  5. Electronic transport properties of phenylacetylene molecular junctions

    International Nuclear Information System (INIS)

    Liu Wen; Cheng Jie; Yan Cui-Xia; Li Hai-Hong; Wang Yong-Juan; Liu De-Sheng

    2011-01-01

    Electronic transport properties of a kind of phenylacetylene compound— (4-mercaptophenyl)-phenylacetylene are calculated by the first-principles method in the framework of density functional theory and the nonequilibrium Green's function formalism. The molecular junction shows an obvious rectifying behaviour at a bias voltage larger than 1.0 V. The rectification effect is attributed to the asymmetry of the interface contacts. Moreover, at a bias voltage larger than 2.0 V, which is not referred to in a relevant experiment [Fang L, Park J Y, Ma H, Jen A K Y and Salmeron M 2007 Langmuir 23 11522], we find a negative differential resistance phenomenon. The negative differential resistance effect may originate from the change of the delocalization degree of the molecular orbitals induced by the bias. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  6. Terbinafine inhibits gap junctional intercellular communication.

    Science.gov (United States)

    Lee, Ju Yeun; Yoon, Sei Mee; Choi, Eun Ju; Lee, Jinu

    2016-09-15

    Terbinafine is an antifungal agent that selectively inhibits fungal sterol synthesis by blocking squalene epoxidase. We evaluated the effect of terbinafine on gap junctional intercellular communication (GJIC). Fluorescence recovery after photobleaching (FRAP) and I-YFP GJIC assays revealed that terbinafine inhibits GJIC in a reversible and dose-dependent manner in FRT-Cx43 and LN215 cells. Treatment with terbinafine did not affect Cx43 phosphorylation status or intracellular Ca(2+) concentration, well-known action mechanisms of various GJIC blockers. While a structurally related chemical, naftifine, attenuated GJIC, epigallocatechin gallate, another potent squalene epoxidase inhibitor with a different structure, did not. These results suggest that terbinafine inhibits GJIC with a so far unknown mechanism of action. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Pentacene-based photodiode with Schottky junction

    International Nuclear Information System (INIS)

    Lee, Jiyoul; Hwang, D.K.; Park, C.H.; Kim, S.S.; Im, Seongil

    2004-01-01

    We have fabricated a metal/organic semiconductor Schottky photodiode based on Al/pentacene junction. Since the energy band gap of thin solid pentacene was determined to be 1.82 eV, as characterized by direct absorption spectroscopy, we measured spectral photoresponses on our Schottky photodiode in the monochromatic light illumination range of 325-650 nm applying a reverse bias of -2 V. The main features of photo-response spectra were found to shift from those of direct absorption spectra toward higher photon energies. It is because the direct absorption spectra mainly show exciton level peaks rather than the true highest occupied molecular orbital (HOMO)-lowest unoccupied molecular orbital (LUMO) gaps while the photo-response spectra clearly represents the true HOMO-LUMO gap. Our photo-response spectra reveal 1.97 eV as the HOMO-LUMO gap

  8. Intercellular coupling mediated by potassium accumulation in peg-and-socket junctions

    DEFF Research Database (Denmark)

    Vigmond, Edward J.; Bardakjian, Berj L.; Thuneberg, Lars

    2000-01-01

    Physiology, peg-and-socket junctions, smooth muscle, boundary element method, coupling, morphology......Physiology, peg-and-socket junctions, smooth muscle, boundary element method, coupling, morphology...

  9. Heated junction thermocouple level measurement apparatus

    International Nuclear Information System (INIS)

    Bevilacqua, F.; Burger, J.M.

    1984-01-01

    A liquid level sensing apparatus senses the level of liquid surrounding the apparatus. A plurality of axially spaced sensors are enclosed in a separator tube. The separator tube tends to collapse the level of a two-phase fluid within the separator tube into essentially a liquid phase and a gaseous phase where the collapsed level bears a relationship to the coolant inventory outside the separator tube. The level of the liquid phase is sensed by level sensing apparatus. The separator tube contains inlet-outlet ports near the top and bottom thereof to equalize the liquid level inside and outside the separator tube when the level fluctuates or the water within the separator tube flashes to steam. Each sensor is comprised of a heater, a heated thermocouple junction and an unheated thermocouple junction within an elongated heat conductive housing. The heated portion of housing is enclosed in a splash guard with inlet-outlet ports near the top and bottom to equalize the liquid level inside and outside the splash guardand to eliminate the spurious indications of liquid level change which may arise if water droplets contact the housing in the region of the heater. To prevent steam bubbles entrained in a two-phase fluid cross flow from entering the lateral inlet-outlet ports of the separator tube, the separator tube is enclosed in support tube which may in turn be enclosed in an otherwise unused control element assembly shroud. The lateral inlet-outlet ports of separator tube are axially offset from lateral inlet-outlet ports of support tube at least where support tube is subjected to cross flow. The shroud is open on the bottom and has lateral inlet-outlet ports to facilitate liquid level fluctuations to equalize inside and outside shroud

  10. High Tc Josephson Junctions, SQUIDs and magnetometers

    International Nuclear Information System (INIS)

    Clarke, J.

    1991-01-01

    There has recently been considerable progress in the state-of-the-art of high-T c magnetometers based on dc SQUIDs (Superconducting Quantum Interference Devices). This progress is due partly to the development of more manufacturable Josephson junctions, making SQUIDs easier to fabricate, and partly to the development of multiturn flux transformers that convert the high sensitivity of SQUIDs to magnetic flux to a correspondingly high sensitivity to magnetic field. Needless to say, today's high-T c SQUIDs are still considerably less sensitive than their low-T c counterparts, particularly at low frequencies (f) where their level of 1/f noise remains high. Nonetheless, the performance of the high-T c devices has now reached the point where they are adequate for a number of the less demanding applications; furthermore, as we shall see, at least modest improvements in performance are expected in the near future. In this article, the author outlines these various developments. This is far from a comprehensive review of the field, however, and, apart from Sec. 2, he describes largely his own work. He begins in Sec. 2 with an overview of the various types of Josephson junctions that have been investigated, and in Sec. 3, he describes some of the SQUIDs that have been tested, and assess their performance. Section 4 discuss the development of the multilayer structures essential for an interconnect technology, and, in particular, for crossovers and vias. Section 5 shows how this technology enables one to fabricate multiturn flux transformers which, in turn, can be coupled to SQUIDs to make magnetometers. The performance and possible future improvements in these magnetometers are assessed, and some applications mentioned

  11. Ligament augmentation for prevention of proximal junctional kyphosis and proximal junctional failure in adult spinal deformity.

    Science.gov (United States)

    Safaee, Michael M; Deviren, Vedat; Dalle Ore, Cecilia; Scheer, Justin K; Lau, Darryl; Osorio, Joseph A; Nicholls, Fred; Ames, Christopher P

    2018-05-01

    OBJECTIVE Proximal junctional kyphosis (PJK) is a well-recognized, yet incompletely defined, complication of adult spinal deformity surgery. There is no standardized definition for PJK, but most studies describe PJK as an increase in the proximal junctional angle (PJA) of greater than 10°-20°. Ligament augmentation is a novel strategy for PJK reduction that provides strength to the upper instrumented vertebra (UIV) and adjacent segments while also reducing junctional stress at those levels. METHODS In this study, ligament augmentation was used in a consecutive series of adult spinal deformity patients at a single institution. Patient demographics, including age; sex; indication for surgery; revision surgery; surgical approach; and use of 3-column osteotomies, vertebroplasty, or hook fixation at the UIV, were collected. The PJA was measured preoperatively and at last follow-up using 36-inch radiographs. Data on change in PJA and need for revision surgery were collected. Univariate and multivariate analyses were performed to identify factors associated with change in PJA and proximal junctional failure (PJF), defined as PJK requiring surgical correction. RESULTS A total of 200 consecutive patients were included: 100 patients before implementation of ligament augmentation and 100 patients after implementation of this technique. The mean age of the ligament augmentation cohort was 66 years, and 67% of patients were women. Over half of these cases (51%) were revision surgeries, with 38% involving a combined anterior or lateral and posterior approach. The mean change in PJA was 6° in the ligament augmentation group compared with 14° in the control group (p historical cohort, ligament augmentation is associated with a significant decrease in PJK and PJF. These data support the implementation of ligament augmentation in surgery for adult spinal deformity, particularly in patients with a high risk of developing PJK and PJF.

  12. Wetting and premelting of triple junctions and grain boundaries in the Al-Zn alloys

    International Nuclear Information System (INIS)

    Straumal, B.; Kogtenkova, O.; Protasova, S.; Mazilkin, A.; Zieba, P.; Czeppe, T.; Wojewoda-Budka, J.; Faryna, M.

    2008-01-01

    Phase transitions in grain boundaries (GBs) and GB triple junctions (TJs) can change drastically the properties of polycrystals. The GB and TJ wetting phase transition can occur in the two-phase area of the bulk phase diagram where the liquid and solid phases are in equilibrium. The GB and TJ wetting tie-lines can continue in one-phase area of the bulk phase diagram as a GB or TJ solidus line. This line represents the GB or TJ premelting phase transition. The structure and composition of grain boundaries and GB triple junctions were studied by high-resolution electron microscopy and analytical transmission electron microscopy in the Al-5 at.% Zn polycrystals and by differential scanning calorimetry (DSC) in the Al-7.5 at.% Zn polycrystals. Between bulk solidus and GB or TJ solidus the metastable Zn-rich β m -phase was observed in the GB triple junctions of quenched samples. This phase appears neither in the samples annealed above the bulk solidus nor in those annealed below the GB solidus. Zn-content in this β m -phase corresponds to that of bulk liquidus. This is a structural indication that if the melt wets the GBs or TJs, the GB (or TJ) solidus line appears in the bulk phase diagram, and the liquid-like phase exists in GBs and TJs between bulk solidus and GB (or TJ) solidus lines. The structural observation of this phase is also supported by our data obtained by means of DSC

  13. Acetylcholine-induced inhibition of presynaptic calcium signals and transmitter release in the frog neuromuscular junction

    Directory of Open Access Journals (Sweden)

    Eduard Khaziev

    2016-12-01

    Full Text Available Acetylcholine (ACh, released from axonal terminals of motor neurones in neuromuscular junctions regulates the efficacy of neurotransmission through activation of presynaptic nicotinic and muscarinic autoreceptors. Receptor-mediated presynaptic regulation could reflect either direct action on exocytotic machinery or modulation of Ca2+ entry and resulting intra-terminal Ca2+ dynamics. We have measured free intra-terminal cytosolic Ca2+ ([Ca2+]i using Oregon-Green 488 microfluorimetry, in parallel with voltage-clamp recordings of spontaneous (mEPC and evoked (EPC postsynaptic currents in post-junctional skeletal muscle fibre. Activation of presynaptic muscarinic and nicotinic receptors with exogenous acetylcholine and its non-hydrolized analogue carbachol reduced amplitude of the intra-terminal [Ca2+]i transients and decreased quantal content (calculated by dividing the area under EPC curve by the area under mEPC curve. Pharmacological analysis revealed the role of muscarinic receptors of M2 subtype as well as d-tubocurarine-sensitive nicotinic receptor in presynaptic modulation of [Ca2+]i transients. Modulation of synaptic transmission efficacy by ACh receptors was completely eliminated by pharmacological inhibition of N-type Ca2+ channels. We conclude that ACh receptor-mediated reduction of Ca2+ entry into the nerve terminal through N-type Ca2+ channels represents one of possible mechanism of presynaptic modulation in frog neuromuscular junction.

  14. Observation of molecular level behavior in molecular electronic junction device

    Science.gov (United States)

    Maitani, Masato

    In this dissertation, I utilize AFM based scanning probe measurement and surface enhanced Raman scattering based vibrational spectroscopic analysis to directly characterize topographic, electronic, and chemical properties of molecules confined in the local area of M3 junction to elucidate the molecular level behavior of molecular junction electronic devices. In the introduction, the characterization of molecular electronic devices with different types of metal-molecule-metal (M3) structures based upon self-assembled monolayers (SAMs) is reviewed. A background of the characterization methods I use in this dissertation, conducting probe atomic force microscopy (cp-AFM) and surface enhanced Raman spectroscopy (SERS), is provided in chapter 1. Several attempts are performed to create the ideal top metal contacts on SAMs by metal vapor phase deposition in order to prevent the metal penetration inducing critical defects of the molecular electronic devices. The scanning probe microscopy (SPM), such as cp-AFM, contact mode (c-) AFM and non-contact mode (nc-) AFM, in ultra high vacuum conditions are utilized to study the process of the metal-SAM interface construction in terms of the correlation between the morphological and electrical properties including the metal nucleation and filament generation as a function of the functionalization of long-chain alkane thiolate SAMs on Au. In chapter 2, the nascent condensation process of vapor phase Al deposition on inert and reactive SAMs are studied by SPM. The results of top deposition, penetration, and filament generation of deposited Al are discussed and compared to the results previously observed by spectroscopic measurements. Cp-AFM was shown to provide new insights into Al filament formation which has not been observed by conventional spectroscopic analysis. Additionally, the electronic characteristics of individual Al filaments are measured. Chapter 3 reveals SPM characterization of Au deposition onto --COOH terminated SAMs

  15. Analysis of the treatment of 576 patients with congenital craniovertebral junction malformations.

    Science.gov (United States)

    Li, Lianfeng; Yu, Xinguang; Wang, Peng; Chen, Lifeng

    2012-01-01

    We aim to report our experience treating craniovertebral junction malformations (CVJM) and to investigate the management of this uncommon condition. Between 2000 and 2009, 629 patients with CVJM underwent surgery in our department. Fifty-three patients were lost to follow-up; therefore 576 patients completed follow-up, for an average period of 3 years and 2 months. All patients were diagnosed on the basis of clinical presentation and imaging features, and we found that anomalies of the occipitocervical junction manifested as four major types. Different microsurgical treatments were carried out in these patients according to disease type, and the effectiveness of individualised treatments was analysed. Categorizing patients with CVJM into these four types to simplify this somewhat unclear area could provide insight into the pathogenesis of the anomaly and a basis for rational surgical treatment. Copyright © 2011. Published by Elsevier Ltd.

  16. Bottom-up, Robust Graphene Ribbon Electronics in All-Carbon Molecular Junctions.

    Science.gov (United States)

    Supur, Mustafa; Van Dyck, Colin; Bergren, Adam J; McCreery, Richard L

    2018-02-21

    Large-area molecular electronic junctions consisting of 5-carbon wide graphene ribbons (GR) with lengths of 2-12 nm between carbon electrodes were fabricated by electrochemical reduction of diazotized 1,8-diaminonaphthalene. Their conductance greatly exceeds that observed for other molecular junctions of similar thicknesses, by a factor of >1 × 10 4 compared to polyphenylenes and >1 × 10 7 compared to alkane chains. The remarkable increase of conductance of the GR nanolayer results from (i) uninterrupted planarity of fused-arene structure affording extensive π-electron delocalization and (ii) enhanced electronic coupling of molecular layer with the carbon bottom contact by two-point covalent bonding, in agreement with DFT-based simulations.

  17. Scanning electron microscopic observations of fibrous structure of cemento-dentinal junction in healthy teeth.

    Science.gov (United States)

    Pratebha, B; Jaikumar, N D; Sudhakar, R

    2014-01-01

    The cemento-dentinal junction (CDJ) is a structural and biologic link between cementum and dentin present in the roots of teeth. Conflicting reports about the origin, structure and composition of this layer are present in literature. The width of this junctional tissue is reported to be about 2-4 μm with adhesion of cementum and dentin by proteoglycans and by collagen fiber intermingling. The objective of this study is to observe and report the fibrous architecture of the CDJ of healthy tooth roots. A total of 15 healthy teeth samples were collected, sectioned into halves, demineralized in 5% ethylenediaminetetraacetic acid, processed using NaOH maceration technique and observed under a scanning electron microscope. The CDJ appeared to be a fibril poor groove with a width of 2-4 µm. Few areas of collagen fiber intermingling could be appreciated. A detailed observation of these tissues has been presented.

  18. Limit load solutions for piping branch junctions under out-of-plane bending

    International Nuclear Information System (INIS)

    Xu, Ying Hu; Lee, Kuk Hee; Jeon, Jun Young; Kim, Yun Jae

    2009-01-01

    Approximate plastic limit load solutions for piping branch junctions under out-of plane bending are obtained from detailed three-dimensional (3-D) FE limit analyses based on elastic-perfectly plastic materials with the small geometry change option. Two types of bending are considered; out-of-plane bending to the branch pipe and out-of-plane bending to the run pipe. Accordingly closed-form approximations are proposed for piping branch junctions under out-of-plane bending based on the FE results. The proposed solutions are valid for the branch-to-run pipe radius and thickness from 0.0 to 1.0, and the mean radius-to-thickness ratio of the run pipe from 2.0 to 20.0. And, this study provides effects of reinforcement area on plastic limit loads.

  19. Numerical Simulation and Analysis of Gas-Liquid Flow in a T-Junction Microchannel

    Directory of Open Access Journals (Sweden)

    Hongtruong Pham

    2012-01-01

    Full Text Available Gas-liquid flow in microchannels is widely used in biomedicine, nanotech, sewage treatment, and so forth. Particularly, owing to the high qualities of the microbubbles and spheres produced in microchannels, it has a great potential to be used in ultrasound imaging and controlled drug release areas; therefore, gas-liquid flow in microchannels has been the focus in recent years. In this paper, numerical simulation of gas-liquid flows in a T-junction microchannel was carried out with computational fluid dynamics (CFD software FLUENT and the Volume-of-Fluid (VOF model. The distribution of velocity, pressure, and phase of fluid in the microchannel was obtained, the pressure distribution along the channel walls was analyzed in order to give a better understanding on the formation of microbubbles in the T-junction microchannel.

  20. Air-water two-phase flow through a pipe junction

    International Nuclear Information System (INIS)

    Suu, Tetsuo

    1991-01-01

    The distribution of the local void fraction across the section of the conduit was studied experimentally in air-water two-phase flow flowing through a pipe junction with the branching angle of 90deg and the area ratio of unity. As in the previous report, the main conduit of the junction was set up vertically and upward air-water bubbly and slug flows were arranged in the main upstream section. If the flow regime, the quality and the ratio of lateral mass flow discharge of water to total mass flow discharge of water are the same, the larger the Reynolds number is, the more violent the variety of the local void fraction distribution adjacent to the branching part in the lateral conduit is. However, the variety in the main downstream section is scarcely influenced by the Reynolds number. (author)

  1. Poster - Thur Eve - 57: Craniospinal irradiation with jagged-junction IMRT approach without beam edge matching for field junctions.

    Science.gov (United States)

    Cao, F; Ramaseshan, R; Corns, R; Harrop, S; Nuraney, N; Steiner, P; Aldridge, S; Liu, M; Carolan, H; Agranovich, A; Karva, A

    2012-07-01

    Craniospinal irradiation were traditionally treated the central nervous system using two or three adjacent field sets. A intensity-modulated radiotherapy (IMRT) plan (Jagged-Junction IMRT) which overcomes problems associated with field junctions and beam edge matching, improves planning and treatment setup efficiencies with homogenous target dose distribution was developed. Jagged-Junction IMRT was retrospectively planned on three patients with prescription of 36 Gy in 20 fractions and compared to conventional treatment plans. Planning target volume (PTV) included the whole brain and spinal canal to the S3 vertebral level. The plan employed three field sets, each with a unique isocentre. One field set with seven fields treated the cranium. Two field sets treated the spine, each set using three fields. Fields from adjacent sets were overlapped and the optimization process smoothly integrated the dose inside the overlapped junction. For the Jagged-Junction IMRT plans vs conventional technique, average homogeneity index equaled 0.08±0.01 vs 0.12±0.02, and conformity number equaled 0.79±0.01 vs 0.47±0.12. The 95% isodose surface covered (99.5±0.3)% of the PTV vs (98.1±2.0)%. Both Jagged-Junction IMRT plans and the conventional plans had good sparing of the organs at risk. Jagged-Junction IMRT planning provided good dose homogeneity and conformity to the target while maintaining a low dose to the organs at risk. Jagged-Junction IMRT optimization smoothly distributed dose in the junction between field sets. Since there was no beam matching, this treatment technique is less likely to produce hot or cold spots at the junction in contrast to conventional techniques. © 2012 American Association of Physicists in Medicine.

  2. The caecocolonic junction in humans has a sphincteric anatomy and function.

    Science.gov (United States)

    Faussone Pellegrini, M S; Manneschi, L I; Manneschi, L

    1995-01-01

    Sphincteric anatomy and function are present at the caecocolonic junction in several mammals. In humans, radiologists and endoscopists have respectively reported a circumferential contraction and a prominent ileocaecal fold at the border area between the caecum and the ascending colon. Anatomical findings on necropsy material failed to confirm its presence. Microscopic studies on surgical specimens showed the existence of muscular and innervational patterns different from those of adjacent areas. The aim of this work was to confirm the existence of a specialised fold at the caecocolonic junction in humans and to ascertain its role by carrying out a study of functional anatomy. Pancolonoscopies were performed on 100 patients and ileocaecal fold behaviour was observed before and after mechanical stimulation. Isolated ileocaecocolonic regions, surgically obtained, were filled with a fixative solution to study their macro and microscopic morphology after stimulation. Endoscopically, the ileocaecal fold was semilunar or circular in shape and spontaneous or evoked spasms occurred in 52 patients. A prominent circular fold could be seen in surgical specimens after stimulation. The entire muscle coat deeply penetrated this fold, showing the features characteristic of the ileocaecal junction. In particular, the inner portion of the circular muscle showed a peculiar arrangement and was thicker than elsewhere. These results show that in humans the caecocolonic junction is provided with a sphincter morphology and function. Little is known about its physiological relevance in ileal flow accommodation and caecal filling and emptying but it should not be underestimated with regard to some colonic motility disorders. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 PMID:7489934

  3. Advance of Mechanically Controllable Break Junction for Molecular Electronics.

    Science.gov (United States)

    Wang, Lu; Wang, Ling; Zhang, Lei; Xiang, Dong

    2017-06-01

    Molecular electronics stands for the ultimate size of functional elements, keeping up with an unstoppable trend over the past few decades. As a vital component of molecular electronics, single molecular junctions have attracted significant attention from research groups all over the world. Due to its pronounced superiority, the mechanically controllable break junctions (MCBJ) technique has been widely applied to characterize the dynamic performance of single molecular junctions. This review presents a system analysis for single-molecule junctions and offers an overview of four test-beds for single-molecule junctions, thus offering more insight into the mechanisms of electron transport. We mainly focus on the development of state-of-the-art mechanically controlled break junctions. The three-terminal gated MCBJ approaches are introduced to manipulate the electron transport of molecules, and MCBJs are combined with characterization techniques. Additionally, applications of MCBJs and remarkable properties of single molecules are addressed. Finally, the challenges and perspective for the mechanically controllable break junctions technique are provided.

  4. Ileocolic junction resection in dogs and cats: 18 cases.

    Science.gov (United States)

    Fernandez, Yordan; Seth, Mayank; Murgia, Daniela; Puig, Jordi

    2017-12-01

    There is limited veterinary literature about dogs or cats with ileocolic junction resection and its long-term follow-up. To evaluate the long-term outcome in a cohort of dogs and cats that underwent resection of the ileocolic junction without extensive (≥50%) small or large bowel resection. Medical records of dogs and cats that had the ileocolic junction resected were reviewed. Follow-up information was obtained either by telephone interview or e-mail correspondence with the referring veterinary surgeons. Nine dogs and nine cats were included. The most common cause of ileocolic junction resection was intussusception in dogs (5/9) and neoplasia in cats (6/9). Two dogs with ileocolic junction lymphoma died postoperatively. Only 2 of 15 animals, for which long-term follow-up information was available, had soft stools. However, three dogs with suspected chronic enteropathy required long-term treatment with hypoallergenic diets alone or in combination with medical treatment to avoid the development of diarrhoea. Four of 6 cats with ileocolic junction neoplasia were euthanised as a consequence of progressive disease. Dogs and cats undergoing ileocolic junction resection and surviving the perioperative period may have a good long-term outcome with mild or absent clinical signs but long-term medical management may be required.

  5. Dilute Nitrides For 4-And 6- Junction Space Solar Cells

    Science.gov (United States)

    Essig, S.; Stammler, E.; Ronsch, S.; Oliva, E.; Schachtner, M.; Siefer, G.; Bett, A. W.; Dimroth, F.

    2011-10-01

    According to simulations the efficiency of conventional, lattice-matched GaInP/GaInAs/Ge triple-junction space solar cells can be strongly increased by the incorporation of additional junctions. In this way the existing excess current of the Germanium bottom cell can be reduced and the voltage of the stack can be increased. In particular, the use of 1.0 eV materials like GaInNAs opens the door for solar cells with significantly improved conversion efficiency. We have investigated the material properties of GaInNAs grown by metal organic vapour phase epitaxy (MOVPE) and its impact on the quantum efficiency of solar cells. Furthermore we have developed a GaInNAs subcell with a bandgap energy of 1.0 eV and integrated it into a GaInP/GaInAs/GaInNAs/Ge 4-junction and a AlGaInP/GaInP/AlGaInAs/GaInAs/GaInNAs/Ge 6- junction space solar cell. The material quality of the dilute nitride junction limits the current density of these devices to 9.3 mA/cm2 (AM0). This is not sufficient for a 4-junction cell but may lead to current matched 6- junction devices in the future.

  6. Solar cell junction temperature measurement of PV module

    KAUST Repository

    Huang, B.J.

    2011-02-01

    The present study develops a simple non-destructive method to measure the solar cell junction temperature of PV module. The PV module was put in the environmental chamber with precise temperature control to keep the solar PV module as well as the cell junction in thermal equilibrium with the chamber. The open-circuit voltage of PV module Voc is then measured using a short pulse of solar irradiation provided by a solar simulator. Repeating the measurements at different environment temperature (40-80°C) and solar irradiation S (200-1000W/m2), the correlation between the open-circuit voltage Voc, the junction temperature Tj, and solar irradiation S is derived.The fundamental correlation of the PV module is utilized for on-site monitoring of solar cell junction temperature using the measured Voc and S at a short time instant with open circuit. The junction temperature Tj is then determined using the measured S and Voc through the fundamental correlation. The outdoor test results show that the junction temperature measured using the present method, Tjo, is more accurate. The maximum error using the average surface temperature Tave as the junction temperature is 4.8 °C underestimation; while the maximum error using the present method is 1.3 °C underestimation. © 2010 Elsevier Ltd.

  7. Electron-beam damaged high-temperature superconductor Josephson junctions

    International Nuclear Information System (INIS)

    Pauza, A.J.; Booij, W.E.; Herrmann, K.; Moore, D.F.; Blamire, M.G.; Rudman, D.A.; Vale, L.R.

    1997-01-01

    Results are presented on the fabrication and characterization of high critical temperature Josephson junctions in thin films of YBa 2 Cu 3 O 7-δ produced by the process of focused electron-beam irradiation using 350 keV electrons. The junctions so produced have uniform spatial current densities, can be described in terms of the resistive shunted junction model, and their current densities can be tailored for a given operating temperature. The physical properties of the damaged barrier can be described as a superconducting material of either reduced or zero critical temperature (T c ), which has a length of ∼15nm. The T c reduction is caused primarily by oxygen Frenkel defects in the Cu - O planes. The large beam currents used in the fabrication of the junctions mean that the extent of the barrier is limited by the incident electron-beam diameter, rather than by scattering within the film. The properties of the barrier can be calculated using a superconductor/normal/superconductor (SNS) junction model with no boundary resistance. From the SNS model, we can predict the scaling of the critical current resistance (I c R n ) product and gain insight into the factors controlling the junction properties, T c , and reproducibility. From the measured I c R n scaling data, we can predict the I c R n product of a junction at a given operating temperature with a given current density. I c R n products of ∼2mV can be achieved at 4.2 K. The reproducibility of several junctions in a number of samples can be characterized by the ratio of the maximum-to-minimum critical currents on the same substrate of less than 1.4. Stability over several months has been demonstrated at room and refrigerator temperatures (297 and 281 K) for junctions that have been initially over damaged and then annealed at temperatures ∼380K. (Abstract Truncated)

  8. The cranial-spinal junction in medulloblastoma: does it matter?

    International Nuclear Information System (INIS)

    Narayana, Ashwatha; Jeswani, Sam; Paulino, Arnold C.

    1999-01-01

    Purpose: Late effects of treatment in children and young adults with medulloblastoma can be influenced by the technique employed in radiating the craniospinal axis. The purpose of this study is to determine whether the placement of the cranial-spinal junction has an impact on dose to the cervical spinal cord and surrounding organs. Methods and Materials: Five patients underwent computed tomography (CT) simulation in the prone position for craniospinal irradiation. A dose of 36 Gy was prescribed to the entire neuraxis. The doses to the cervical spinal cord and surrounding organs were calculated using a cranial-spinal junction at the C1-C2 vertebral interspace (high junction) or at the lowest point in the neck, with exclusion of the shoulders in the lateral cranial fields (low junction).The volume of critical organs at risk, as well as dose to these structures using the cranial and spinal field(s) were outlined and calculated using the CMS FOCUS 3-dimensional treatment planning system. Results: The average dose to the cervical spinal cord was 11.9% higher than the prescribed dose with the low junction, and 6.7% higher with the high junction. However, doses to the thyroid gland, mandible, pharynx, and larynx were increased by an average of 29.6%, 75.8%, 70.6%, and 227.7%, respectively, by the use of the high junction compared to the low junction. Conclusion: A higher dose to the cervical spinal cord can be minimized by using a high junction. However, this would be at the cost of substantially increased doses to surrounding organs such as the thyroid gland, mandible, pharynx, and larynx. This can be critical in children and young adults, where hypothyroidism, mandibular hypoplasia, and development of second malignancies may be a late sequela of radiation therapy

  9. Internal resonances in periodically modulated long Josephson junctions

    DEFF Research Database (Denmark)

    Larsen, Britt Hvolbæk; Mygind, Jesper; Ustinov, Alexey V.

    1995-01-01

    Current-voltage (I-V) characteristics of long Josephson junctions with a periodic lattice of localized inhomogeneities are studied. The interaction between the moving fluxons and the inhomogeneities causes resonant steps in the IV-curve. Some of these steps are due to a synchronization to resonant...... Fiske modes in the sub-junctions formed between the inhomogeneities. The voltage positions of the resonant steps oscillate as function of the applied magnetic field with a period corresponding to the inclusion of one magnetic flux quantum, Φ0=h/2e, per sub-junction. A qualitative explanation that takes...

  10. Temporal correlations and structural memory effects in break junction measurements

    DEFF Research Database (Denmark)

    Magyarkuti, A.; Lauritzen, Kasper Primdal; Balogh, Zoltan Imre

    2017-01-01

    that correlations between the opening and subsequent closing traces may indicate structural memory effects in atomic-sized metallic and molecular junctions. Applying these methods on measured and simulated gold metallic contacts as a test system, we show that the surface diffusion induced flattening of the broken......-molecule junctions, we demonstrate pronounced contact memory effects and recovery of the molecule for junctions breaking before atomic chains are formed. However, if chains are pulled the random relaxation of the chain and molecule after rupture prevents opening-closing correlations....

  11. Double-well potential in annular Josephson junction

    International Nuclear Information System (INIS)

    Shaju, P.D.; Kuriakose, V.C.

    2004-01-01

    A double-well potential suitable for quantum-coherent vortex tunnelling can be created in an annular Josephson junction by inserting a microshort in the junction and by applying an in-plane dc magnetic field. Analysis shows that the intensity of the magnetic field determines the depth of the potential well and the strength of the microshort controls the potential barrier height while a dc bias across the junction tilts the potential well. At milli-Kelvin temperatures, the system is expected to behave as a quantum two-level system and may be useful in designing vortex qubits

  12. Steady-state properties of Josephson junctions with direct conductivity

    International Nuclear Information System (INIS)

    Zubkov, A.A.; Kupriyanov, M.Y.; Semenov, V.K.

    1981-01-01

    A new criterion for determining the kinetic inductance of Josephson junctions is introduced. The effects of temperature T, the critical temperatures of the superconducting electrodes T/sub c/1 and T/sub c/2, and the weak-link length on the kinetic inductance of ''dirty'' junctions with direct conductivity are analyzed within the framework of the Usadel equations. Numerical calculations show that both a large characteristic voltage and a nearly harmonic dependence of the current on the phase difference of the superconducting-electrode wave functions cannot be obtained by varying the junction parameters

  13. Amorphous molecular junctions produced by ion irradiation on carbon nanotubes

    International Nuclear Information System (INIS)

    Wang Zhenxia; Yu Liping; Zhang Wei; Ding Yinfeng; Li Yulan; Han Jiaguang; Zhu Zhiyuan; Xu Hongjie; He Guowei; Chen Yi; Hu Gang

    2004-01-01

    Experiments and molecular dynamics have demonstrated that electron irradiation could create molecular junctions between crossed single-wall carbon nanotubes. Recently molecular dynamics computation predicted that ion irradiation could also join single-walled carbon nanotubes. Employing carbon ion irradiation on multi-walled carbon nanotubes, we find that these nanotubes evolve into amorphous carbon nanowires, more importantly, during the process of which various molecular junctions of amorphous nanowires are formed by welding from crossed carbon nanotubes. It demonstrates that ion-beam irradiation could be an effective way not only for the welding of nanotubes but also for the formation of nanowire junctions

  14. No junctional communication between epithelial cells in hydra

    DEFF Research Database (Denmark)

    de Laat, S W; Tertoolen, L G; Grimmelikhuijzen, C J

    1980-01-01

    junctions between epithelial cells of hydra. However, until now, there has been no report published on whether these junctions enable the epithelial cells to exchange molecules of small molecular weight, as has been described in other organisms. Therefore we decided to investigate the communicative...... properties of the junctional membranes by electrophysiological methods and by intracellular-dye iontophoresis. We report here that no electrotonic coupling is detectable between epithelial cells of Hydra attenuata in: (1) intact animals, (2) head-regenerating animals, (3) cell re-aggregates, and (4) hydra...

  15. Ischemic preconditioning protects against gap junctional uncoupling in cardiac myofibroblasts.

    Science.gov (United States)

    Sundset, Rune; Cooper, Marie; Mikalsen, Svein-Ole; Ytrehus, Kirsti

    2004-01-01

    Ischemic preconditioning increases the heart's tolerance to a subsequent longer ischemic period. The purpose of this study was to investigate the role of gap junction communication in simulated preconditioning in cultured neonatal rat cardiac myofibroblasts. Gap junctional intercellular communication was assessed by Lucifer yellow dye transfer. Preconditioning preserved intercellular coupling after prolonged ischemia. An initial reduction in coupling in response to the preconditioning stimulus was also observed. This may protect neighboring cells from damaging substances produced during subsequent regional ischemia in vivo, and may preserve gap junctional communication required for enhanced functional recovery during subsequent reperfusion.

  16. Superconducting proximity effect in mesoscopic superconductor/normal-metal junctions

    CERN Document Server

    Takayanagi, H; Toyoda, E

    1999-01-01

    The superconducting proximity effect is discussed in mesoscopic superconductor/normal-metal junctions. The newly-developed theory shows long-range phase-coherent effect which explaines early experimental results of giant magnetoresistance oscillations in an Andreev interferometer. The theory also shows that the proximity correction to the conductance (PCC) has a reentrant behavior as a function of energy. The reentrant behavior is systematically studied in a gated superconductor-semiconductor junction. A negative PCC is observed in the case of a weak coupling between the normal metal and the external reservoir. Phase coherent ac effect is also observed when rf is irradiated to the junction.

  17. A comparative study of noise pollution levels in some selected areas in Ilorin Metropolis, Nigeria.

    Science.gov (United States)

    Oyedepo, Olayinka S; Saadu, Abdullahi A

    2009-11-01

    The noise pollution is a major problem for the quality of life in urban areas. This study was conducted to compare the noise pollution levels at busy roads/road junctions, passengers loading parks, commercial, industrial and residential areas in Ilorin metropolis. A total number of 47-locations were selected within the metropolis. Statistical analysis shows significant difference (P noise pollution levels between industrial areas and low density residential areas, industrial areas and high density areas, industrial areas and passengers loading parks, industrial areas and commercial areas, busy roads/road junctions and low density areas, passengers loading parks and commercial areas and commercial areas and low density areas. There is no significant difference (P > 0.05) in noise pollution levels between industrial areas and busy roads/road junctions, busy roads/road junctions and high density areas, busy roads/road junctions and passengers loading parks, busy roads/road junctions and commercial areas, passengers loading parks and high density areas, passengers loading parks and commercial areas and commercial areas and high density areas. The results show that Industrial areas have the highest noise pollution levels (110.2 dB(A)) followed by busy roads/Road junctions (91.5 dB(A)), Passengers loading parks (87.8 dB(A)) and Commercial areas (84.4 dB(A)). The noise pollution levels in Ilorin metropolis exceeded the recommended level by WHO at 34 of 47 measuring points. It can be concluded that the city is environmentally noise polluted and road traffic and industrial machineries are the major sources of it. Noting the noise emission standards, technical control measures, planning and promoting the citizens awareness about the high noise risk may help to relieve the noise problem in the metropolis.

  18. Influence of the spacer dielectric processes on PMOS junction properties

    International Nuclear Information System (INIS)

    Morin, Pierre; Wacquant, Francois; Juhel, Marc; Laviron, Cyrille; Lenoble, D.

    2005-01-01

    In this paper, the interaction observed in PMOS transistor between the boron lightly doped drain (LDD) extensions and the spacer oxide and nitride dielectrics have been studied, with a simple experimental methodology. Low thermal budget oxide obtained by sub-atmospheric chemical vapor deposition (SACVD) and nitride deposited by plasma process have been evaluated as spacer layers. The influence of the oxide liner hydrogen content is shown to be critical for the p type shallow junction. Indeed, during the activation anneal, hydrogen content increases the boron out diffusion from the extension into the oxide liner and yield to a significant dose loss in this area. Nitride porosity has also been studied. A lower boron dose loss is observed with a porous layer because hydrogen can degas out significantly from the oxide, during anneal, through the porous nitride film. These results confirm the model of boron out diffusion based on oxide hydrogen content proposed by Kohli. Finally, a boron diffusion mechanism driven by chemistry and enhanced by hydrogen defects is proposed

  19. Extrinsic stretching narrowing and anterior indentation of the rectosigmoid junction

    International Nuclear Information System (INIS)

    Schulman, A.; Fataar, S.

    1979-01-01

    Thirty-five cases of extrinsic narrowing or anterior indentation of the rectosigmoid junction (RSJ) have been studied. The RSJ lies directly behind the pouch of Douglas which is a favoured site for peritoneal metastasis, abscess and endometriosis. Any space-occupying lesion of sufficient size at this site will indent the anterior aspects of the RSJ. Causes include distension or tumour of the ileum or sigmoid colon, gross ascites (when the patient is erect), and tumours below the pelvic peritonium, such as gynaecological neoplasm and internal iliac artery aneurysm. When a desmoplastic metastasis in the pouch of Douglas infiltrates the outer layers of the RSJ, the fibrosis produces an eccentric shortening on its anterior aspect, which in turn causes a pleating of the mucosa with the folds radiating towards the shortened area. This is also seen with primary pelvic carcinomas directly adherent to the rectum, endometriosis with repeated bleeding and increasing eccentric, submucosal fibrosis, and chronic abscess in the pouch of Douglas. Not all extrinsic narrowing of the RSJ are pathological. One case of anterior indentation followed operation for rectal prolapse. Ten additional cases showed narrowing due to a technical artefact air-distended colon rising into the upper abdomen to cause stretching at the RSJ. As with ascites, this narrowing due to 'high-rise sigmoid' disappeared when the patients became recumbent and the colonic air redistributed. (author)

  20. CLASSIFICATION AND QUANTITATIVE ANALYSIS OF GEOGRAPHIC ATROPHY JUNCTIONAL ZONE USING SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY.

    Science.gov (United States)

    Qu, Jinfeng; Velaga, Swetha Bindu; Hariri, Amir H; Nittala, Muneeswar Gupta; Sadda, Srinivas

    2017-08-22

    The junctional zone at the border of areas of geographic atrophy (GA) in eyes with nonneovascular age-related macular degeneration is an important target region for future therapeutic strategies. The goal of this study was to perform a detailed classification and quantitative characterization of the junctional zone using spectral domain optical coherence tomography. Spectral domain optical coherence tomography volume cube scans (Spectralis OCT, 1024 × 37, Automatic Real Time > 9) were obtained from 15 eyes of 11 patients with GA because of nonneovascular age-related macular degeneration. Volume optical coherence tomography data were imported into previously described validated grading software (3D-OCTOR), and manual segmentation of the retinal pigment epithelium (RPE) and photoreceptor layers was performed on all B-scans (total of 555). Retinal pigment epithelium and photoreceptor defect maps were produced for each case. The borders of the photoreceptor defect area and RPE defect area were delineated individually on separate annotation layers. The two outlines were then superimposed to compare the areas of overlap and nonoverlap. The perimeter of the RPE defect area was calculated by the software in pixels. The superimposed outline of the photoreceptor defect area and the RPE defect area was scrutinized to classify the overlap configuration of the junctional zone into one of three categories: Type 0, exact correspondence between the edge of the RPE defect and photoreceptor defect; Type 1, loss of photoreceptors outside and beyond the edge of the RPE defect; Type 2, preservation of photoreceptors beyond the edge of the RPE defect. The relative proportion of the various border configurations was expressed as a percentage of the perimeter of the RPE defect. Each configuration was then classified into four subgroups according to irregularity of the RPE band and the presence of debris. Fifteen eyes of 11 patients (mean age: 79.3 ± 4.3 years; range: 79-94 years) were

  1. Optical imaging of the transport properties of S-Sm-S junctions

    International Nuclear Information System (INIS)

    Tsumura, K; Nomura, S; Akazaki, T; Takayanagi, H

    2009-01-01

    We study the optical effects on superconductor-normal metal superconductor (S-Sm-S) junctions composed of two-dimensional electron gas (2DEG) in a GaAs/AlGaAs heterostructure and NbN superconducting electrodes. When the whole junction area was illuminated at λ = 800 nm, we observe a reduction in the normal resistance due to an increase in the sheet carrier density of the 2DEG, and the enhancement of the Andreev reflection probability. To reveal its origin, we performed scanning photo-voltage measurement by employing an optical microscope. The obtained image plots show maxima and minima of the photo-voltage change along the S-Sm interfaces. Those structures are considered to reflect the modulation of the barrier height at S-Sm interface and the increase in the scattering by photo-generated carriers. It is demonstrated that the scanning photo-voltage measurement is one of the most powerful tools as a local probe of the transport properties of S-Sm-S junctions.

  2. Development of Nb nanoSQUIDs based on SNS junctions for operation in high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Morosh, Viacheslav; Kieler, Oliver; Weimann, Thomas; Zorin, Alexander [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany); Mueller, Benedikt; Martinez-Perez, Maria Jose; Kleiner, Reinhold; Koelle, Dieter [Physikalisches Institut and Center for Quantum Science in LISA+, Universitaet Tuebingen (Germany)

    2016-07-01

    Investigation of the magnetization reversal of single magnetic nanoparticles requires SQUIDs with high spatial resolution, high spin sensitivity (a few Bohr magneton μ{sub B}) and at the same time sufficient stability in high magnetic fields. We fabricated dc nanoSQUIDs comprising overdamped SNS sandwich-type (Nb/HfTi/Nb) Josephson junctions using optimized technology based on combination of electron beam lithography and chemical-mechanical polishing. Our nanoSQUIDs have Josephson junctions with lateral dimensions ≤ 150 nm x 150 nm, effective loop areas < 0.05 μm{sup 2} and the distance between the Josephson junctions ≤ 100 nm. The feeding strip lines of the width ≤ 200 nm have been realized. The nanoSQUIDs have shown stable operation in external magnetic fields at least up to 250 mT. Sufficiently low level of flux noise resulting in spin sensitivity of few tens μ{sub B}/Hz{sup 1/2} has been demonstrated. A further reduction of the nanoSQUID size using our technology is possible.

  3. CT-findings in pain syndromes originated from thoraco-lumbar junction

    International Nuclear Information System (INIS)

    Dimitrov, I.; Karadjova, M.; Malchanova, V.

    2007-01-01

    The thoraco-lumbar junction syndrome imitates, as far as clinical symptoms are concerned, low back pain, caused by disc protrusion in the lower lumbar vertebral segments. It is manifested by referred pain in the area, innervated by posterior and anterior primary rami (dorsal and ventral rami), belonging to thoraco-lumbar junction vertebral segments (Th11-L2). Eighty one patients with clinically diagnosed thoraco-lumbar junction syndrome underwent CT-investigations, that aimed establishing pathological processes, leading to this clinical symptomatology. 148 vertebral levels were examined. In 67 patients we scanned two consecutive levels to find the type of change of the zygapophyseal joints. We found facet tropism (asymmetry) in 72 patients (88.8%) or in 117 levels (79.6%), degenerated faced joints in 63 patients (77.8%), pathology of the intervertebral disc - in 33 patients (43.1%) including 5 patients (6.2%) with disc prolapse. When investigating on two subsequent segments (Th11-Th12 and Th12-L1) sudden anatomical change in orientation of facets occurred in 55 patients (82%). Our findings support the hypothesis of the facet-joint origin of this ailment. (authors)

  4. A cephalometric method to diagnosis the craniovertebral junction abnormalities in osteogenesis imperfecta patients

    Science.gov (United States)

    Ríos-Rodenas, Mercedes; Gutiérrez-Díez, María-Pilar; Feijóo, Gonzalo; Mourelle, Maria-Rosa; Garcilazo, Mario; Ortega-Aranegui, Ricardo

    2015-01-01

    Osteogenesis imperfecta (OI) is a hereditary bone fragility disorder that in most patients is caused by mutations affecting collagen type I. Their typical oral and craneofacial characteristics (Dentinogenesis imperfecta type I and class III malocclusion), involve the dentist in the multidisciplinary team that treat these patients. It is usual to perform lateral skull radiographs for the orthodontic diagnosis. In addition, this radiograph is useful to analyse the junctional area between skull base and spine, that could be damaged in OI. Pathology in the craneovertebral junction (CVJ) is a serious complication of OI with a prevalence ranging from rare to 37%. To diagnosis early skull base anomalies in these patients, previously the neurological symptoms have been appear, we make a simple cephalometric analysis of the CVJ. This method has four measurements and one angle. Once we calculate the values of the OI patient, we compare the result with the mean and the standard deviations of an age-appropriate average in healthy controls. If the patient has a result more than 2,5 SDs above the age-appropriate average in healthy controls, we should to refer the patient to his/her pediatrician or neurologist. These doctors have to consider acquiring another diagnostic images to be used to determine cranial base measurements with more reliability. Thereby, dentists who treat these patients, must be aware of the normal radiological anatomy of the cervical spine on the lateral cephalogram. Key words:Osteogenesis imperfecta, craniovertebral junction, cephalometric. PMID:25810828

  5. Effects of adenine nucleotide and sterol depletion on tight junction structure and function in MDCK cells

    International Nuclear Information System (INIS)

    Ladino, C.A.

    1988-01-01

    The antitumor agent Hadacidin (H), N-formyl-hydroxyamino-acetic acid, reversibly inhibited the multiplication of clone 4 Madin-Darby canine kidney (MDCK) cells at a 4 mM concentration within 24-48 hours. Treated cells were arrested in the S phase of the cell cycle. Accompanying this action was a 16-fold increase in the area occupied b the cells and a refractoriness to trypsin treatment. To test whether this effect was due to an increase in tight junction integrity, electrical resistance (TER) was measured across H-treated monolayers. Addition of H at the onset of junction formation reversibly prevented the development of TER. ATP and cAMP levels were decreased by H, as well as the rate of [ 3 H]-leucine incorporation into protein. When 1 mM dibutyryl-cAMP (d.cAMP) and theophylline were added, H had no effect on cell division or protein synthesis, and TER was partially restored. The addition of 1 mM d.cAMP and 1 mM theophylline to control cultures decreased TER, indicating a biphasic effect on TER development/maintenance. In a separate study, the effect of sterol depletion on tight junctions formation/maintenance in wild-type MDCK cells was investigated

  6. National Uranium Resource Evaluation. Bibliographic index of Grand Junction office uranium reports

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.B.

    1981-05-01

    In October 1978, Mesa College entered into subcontract with Bendix Field Engineering Corporation (BFEC) to prepare a bibliographic index of the uranium raw materials reports issued by the Grand Junction Office of the US Department of Energy (DOE). Bendix, prime contractor to the Grand Junction Office, operates the Technical Library at the DOE facility. Since the early 1950s, approximately 2700 reports have been issued by the Grand Junction Office. These reports were the results of uranium investigations conducted by federal agencies and their subcontractors. The majority of the reports cover geology, mineralogy, and metallurgy of uranium and/or thorium. No single, complete list of these reports existed. The purpose of this subcontract was to compile a comprehensive index to these reports. The Mesa College geology faculty worked with the BFEC and DOE staffs to develop the format for the index. Undergraduate geology students from Mesa compiled a master record sheet for each report. All reports issued up to January 1, 1979 were included in the bibliography. The bibliography is in preliminary, unedited form. It is being open-filed at this time, on microfiche, to make the information available to the public on a timely basis. The bibliography is divided into a master record list arranged in alpha-numeric order by report identification number, with separate indices arranged by title, author, state and county, 1/sup 0/ x 2/sup 0/ NTMS quadrangle, key words, and exploration area.

  7. National Uranium Resource Evaluation. Bibliographic index of Grand Junction office uranium reports

    International Nuclear Information System (INIS)

    Johnson, J.B.

    1981-05-01

    In October 1978, Mesa College entered into subcontract with Bendix Field Engineering Corporation (BFEC) to prepare a bibliographic index of the uranium raw materials reports issued by the Grand Junction Office of the US Department of Energy (DOE). Bendix, prime contractor to the Grand Junction Office, operates the Technical Library at the DOE facility. Since the early 1950s, approximately 2700 reports have been issued by the Grand Junction Office. These reports were the results of uranium investigations conducted by federal agencies and their subcontractors. The majority of the reports cover geology, mineralogy, and metallurgy of uranium and/or thorium. No single, complete list of these reports existed. The purpose of this subcontract was to compile a comprehensive index to these reports. The Mesa College geology faculty worked with the BFEC and DOE staffs to develop the format for the index. Undergraduate geology students from Mesa compiled a master record sheet for each report. All reports issued up to January 1, 1979 were included in the bibliography. The bibliography is in preliminary, unedited form. It is being open-filed at this time, on microfiche, to make the information available to the public on a timely basis. The bibliography is divided into a master record list arranged in alpha-numeric order by report identification number, with separate indices arranged by title, author, state and county, 1 0 x 2 0 NTMS quadrangle, key words, and exploration area

  8. Scintigraphic investigation of clavicular bone area in patients with psoriasis

    International Nuclear Information System (INIS)

    Aso, Kazuo; Amano, Michiko; Sekiya, Sakae; Komatani, Akio

    1984-01-01

    Bone scintigraphy with sup(99m)Tc-methylene diphosphonate (MDP) was performed in 38 patients with psoriasis, 5 patients with palmoplantar pustulosis, and 56 control subjects. Abnormal uptake was seen primarily in the sternoclavicular junction and the cartilage of the first rib in 24 of the patients with psoriasis (63%) and in 3 of the patients with palmoplantar pustulosis (60%), and in the sternoclavicular junction in 21 of the control subjects (38%). The incidence of uptake in the sternoclavicular junction area in the psoriasis patients clearly exceeded that in the control subjects. (Namekawa, K.)

  9. Charge transport in single photochromic molecular junctions

    Science.gov (United States)

    Kim, Youngsang; Pietsch, T.; Scheer, Elke; Hellmuth, T.; Pauly, F.; Sysoiev, D.; Huhn, T.; Exner, T.; Groth, U.; Steiner, U.; Erbe, A.

    2012-02-01

    Recently, photoswitchable molecules, i.e. diarylethene, gained significant interest due to their applicability in data storage media, as optical switches, and in novel logic circuits [1]. Diarylethene-derivative molecules are the most promising candidates to design electronic functional elements, because of their excellent thermal stability, high fatigue resistance, and negligible change upon switching [1]. Here, we present the preferential conductance of specifically designed sulfur-free diarylethene molecules [2] bridging the mechanically controlled break-junctions at low temperatures [3]. The molecular energy levels and electrode couplings are obtained by evaluating the current-voltage characteristics using the single-level model [4]. The charge transport mechanism of different types of diarylethene molecules is investigated, and the results are discussed within the framework of novel theoretical predictions. [4pt] [1] M. Del Valle etal., Nat Nanotechnol 2, 176 (2007) S. J. van der Molen etal., Nano. Lett. 9, 76 (2009).[0pt] [2] D. Sysoiev etal., Chem. Eur. J. 17, 6663 (2011).[0pt] [3] Y. Kim etal., Phys. Rev. Lett. 106, 196804 (2011).[0pt] [4] Y. Kim etal., Nano Lett. 11, 3734 (2011). L. Zotti etal., Small 6, 1529 (2010).

  10. Motor neuron, nerve, and neuromuscular junction disease.

    Science.gov (United States)

    Finsterer, Josef; Papić, Lea; Auer-Grumbach, Michaela

    2011-10-01

    The aim is to review the most relevant findings published during the last year concerning clinical, genetic, pathogenic, and therapeutic advances in motor neuron disease, neuropathies, and neuromuscular junction disorders. Studies on animal and cell models have improved the understanding of how mutated survival motor neuron protein in spinal muscular atrophy governs the pathogenetic processes. New phenotypes of SOD1 mutations have been described. Moreover, animal models enhanced the insight into the pathogenetic background of sporadic and familial amyotrophic lateral sclerosis. Novel treatment options for motor neuron disease have been described in humans and animal models. Considerable progress has been achieved also in elucidating the genetic background of many forms of inherited neuropathies and high clinical and genetic heterogeneity has been demonstrated. Mutations in MuSK and GFTP1 have been shown to cause new types of congenital myasthenic syndromes. A third type of autoantibodies (Lrp4) has been detected to cause myasthenia gravis. Advances in the clinical and genetic characterization of motor neuron diseases, neuropathies, and neuromuscular transmission defects have important implications on the fundamental understanding, diagnosis, and management of these disorders. Identification of crucial steps of the pathogenetic process may provide the basis for the development of novel therapeutic strategies.

  11. Nuclear radiation detection with superconducting tunnel junctions

    International Nuclear Information System (INIS)

    Kurakado, Masahiko

    1984-01-01

    Since the gap energy of superconductors is as small as 1 meV and 1/1000 of that of semiconductors, it is expected that the number of electron-hole pairs produced in superconductors by radiation is several thousands times as many as the pairs in semiconductors. Therefore, high sensitivity and high resolution radiation detectors may be manufactured by using superconductors. A computer simulation of the cascade excitation process of electrons was carried out. The experimental study was performed by using Sn junctions. The variation of transient voltage was measured by the constant current method. The alpha particles from Po-210 were measured, and the generation of quasi particles was confirmed. The relaxation time of signals was measured by using pulsed laser beam. It was found that the superconductors just after the incidence of radiation became nonequilibrium. The typical alpha spectra were obtained by cooling the superconductors to 0.32 K. The detector is still under development. The problem is leakage current. (Kato, T.)

  12. Aeroacoustics of T-junction merging flow.

    Science.gov (United States)

    Lam, G C Y; Leung, R C K; Tang, S K

    2013-02-01

    This paper reports a numerical study of the aeroacoustics of merging flow at T-junction. The primary focus is to elucidate the acoustic generation by the flow unsteadiness. The study is conducted by performing direct aeroacoustic simulation approach, which solves the unsteady compressible Navier-Stokes equations and the perfect gas equation of state simultaneously using the conservation element and solution element method. For practical flows, the Reynolds number based on duct width is usually quite high (>10(5)). In order to properly account for the effects of flow turbulence, a large eddy simulation methodology together with a wall modeling derived from the classical logarithm wall law is adopted. The numerical simulations are performed in two dimensions and the acoustic generation physics at different ratios of side-branch to main duct flow velocities VR (=0.5,0.67,1.0,2.0) are studied. Both the levels of unsteady interactions of merging flow structures and the efficiency of acoustic generation are observed to increase with VR. Based on Curle's analogy, the major acoustic source is found to be the fluctuating wall pressure induced by the flow unsteadiness occurred in the downstream branch. A scaling between the wall fluctuating force and the efficiency of the acoustic generation is also derived.

  13. Development of a junction β - spectrometer

    International Nuclear Information System (INIS)

    Hashizume, A.

    1966-01-01

    A β spectrometry unit using junctions of the silicon surface barrier type has been built. The resolving power of this spectrometer has been studied as well as the influence of a certain number of parameters (temperature, polarization voltage) on its characteristics. A study with this unit of some internal conversion electron spectra ( 113 Sn, 137 Cs, 139 Ce, 195 Au, 207 Bi) has led both to a determination of its characteristics and of an energy calibration, and to the determination of certain internal conversion ratios of these radionuclides. This spectrometer was then used for a study of (5-spectra in particular that of 35 S and 14 C. The calculations and corrections required for the setting-up of Kuries representation are described. The programmes required for the carrying-out of these calculations with an I.B.M. computer are given. It has been verified that Kuries representation for 14 C above 90 keV is in fact linear. The non-linear aspect observed by certain authors is probably due to the 'quality' of the sources used. The Fierz interference term has been determined. The maximum β energies found are respectively: 167 ± 1 keV for 35 S and 155 ± 2 keV for 14 C. (author) [fr

  14. Perturbation treatment of mixing in Josephson junctions

    International Nuclear Information System (INIS)

    Levinsen, M.T.; Ulrich, B.T.

    1975-01-01

    A current biased, resistively shunted Josephson Junction irradiated at two frequencies is considered. The perturbation technique introduced by Aslamasov and Larkin is used in the calculations, and both signals are treated as perturbations. The second order calculation yields the size of the mixing steps at V/sub +-/ = h(ω 1 +- ω 2 )/2e. As in the case of a single frequency, subharmonic mixing steps are absent. The amplitude of the voltage oscillation at the difference and sum frequencies is shown to be non-zero at all voltages. The microwave resistance is calculated for one frequency ω 2 to third order in the perturbation. There are negative resistance regions near V/sub +-/ (as well as near V 2 = hω 2 /2e). Near V/sub -/, the negative resistance region appears for bias voltage V just above V/sub -/, while near V the region appears for V just below V/sub +/. This means that when an incident frequency mixes with a cavity mode, the mixing step at V/sub -/ will be inverted compared to the cavity step itself

  15. Modeling Bloch oscillations in ultra-small Josephson junctions

    Science.gov (United States)

    Vora, Heli; Kautz, Richard; Nam, Sae Woo; Aumentado, Jose

    In a seminal paper, Likharev et al. developed a theory for ultra-small Josephson junctions with Josephson coupling energy (Ej) less than the charging energy (Ec) and showed that such junctions demonstrate Bloch oscillations which could be used to make a fundamental current standard that is a dual of the Josephson volt standard. Here, based on the model of Geigenmüller and Schön, we numerically calculate the current-voltage relationship of such an ultra-small junction which includes various error processes present in a nanoscale Josephson junction such as random quasiparticle tunneling events and Zener tunneling between bands. This model allows us to explore the parameter space to see the effect of each process on the width and height of the Bloch step and serves as a guide to determine whether it is possible to build a quantum current standard of a metrological precision using Bloch oscillations.

  16. Large eddy simulation of a wing-body junction flow

    Science.gov (United States)

    Ryu, Sungmin; Emory, Michael; Campos, Alejandro; Duraisamy, Karthik; Iaccarino, Gianluca

    2014-11-01

    We present numerical simulations of the wing-body junction flow experimentally investigated by Devenport & Simpson (1990). Wall-junction flows are common in engineering applications but relevant flow physics close to the corner region is not well understood. Moreover, performance of turbulence models for the body-junction case is not well characterized. Motivated by the insufficient investigations, we have numerically investigated the case with Reynolds-averaged Naiver-Stokes equation (RANS) and Large Eddy Simulation (LES) approaches. The Vreman model applied for the LES and SST k- ω model for the RANS simulation are validated focusing on the ability to predict turbulence statistics near the junction region. Moreover, a sensitivity study of the form of the Vreman model will also be presented. This work is funded under NASA Cooperative Agreement NNX11AI41A (Technical Monitor Dr. Stephen Woodruff)

  17. Doping enhanced barrier lowering in graphene-silicon junctions

    Science.gov (United States)

    Zhang, Xintong; Zhang, Lining; Chan, Mansun

    2016-06-01

    Rectifying properties of graphene-semiconductor junctions depend on the Schottky barrier height. We report an enhanced barrier lowering in graphene-Si junction and its essential doping dependence in this paper. The electric field due to ionized charge in n-type Si induces the same type doping in graphene and contributes another Schottky barrier lowering factor on top of the image-force-induced lowering (IFIL). We confirm this graphene-doping-induced lowering (GDIL) based on well reproductions of the measured reverse current of our fabricated graphene-Si junctions by the thermionic emission theory. Excellent matching between the theoretical predictions and the junction data of the doping-concentration dependent barrier lowering serves as another evidence of the GDIL. While both GDIL and IFIL are enhanced with the Si doping, GDIL exceeds IFIL with a threshold doping depending on the as-prepared graphene itself.

  18. Negative tunnel magnetoresistance and spin transport in ferromagnetic graphene junctions

    International Nuclear Information System (INIS)

    Zou Jianfei; Jin Guojun; Ma Yuqiang

    2009-01-01

    We study the tunnel magnetoresistance (TMR) and spin transport in ferromagnetic graphene junctions composed of ferromagnetic graphene (FG) and normal graphene (NG) layers. It is found that the TMR in the FG/NG/FG junction oscillates from positive to negative values with respect to the chemical potential adjusted by the gate voltage in the barrier region when the Fermi level is low enough. Particularly, the conventionally defined TMR in the FG/FG/FG junction oscillates periodically from a positive to negative value with increasing the barrier height at any Fermi level. The spin polarization of the current through the FG/FG/FG junction also has an oscillating behavior with increasing barrier height, whose oscillating amplitude can be modulated by the exchange splitting in the ferromagnetic graphene.

  19. Negative tunnel magnetoresistance and spin transport in ferromagnetic graphene junctions.

    Science.gov (United States)

    Zou, Jianfei; Jin, Guojun; Ma, Yu-Qiang

    2009-03-25

    We study the tunnel magnetoresistance (TMR) and spin transport in ferromagnetic graphene junctions composed of ferromagnetic graphene (FG) and normal graphene (NG) layers. It is found that the TMR in the FG/NG/FG junction oscillates from positive to negative values with respect to the chemical potential adjusted by the gate voltage in the barrier region when the Fermi level is low enough. Particularly, the conventionally defined TMR in the FG/FG/FG junction oscillates periodically from a positive to negative value with increasing the barrier height at any Fermi level. The spin polarization of the current through the FG/FG/FG junction also has an oscillating behavior with increasing barrier height, whose oscillating amplitude can be modulated by the exchange splitting in the ferromagnetic graphene.

  20. BPS dynamics of the triple (p,q) string junction

    International Nuclear Information System (INIS)

    Rey, S.-J.; Yee, J.-T.

    1998-01-01

    We study the dynamics of the triple junction of (p,q) strings in type IIB string theory. We probe the tension and mass density of (p,q) strings by studying harmonic fluctuations of the triple junction. We show that they agree perfectly with the BPS formula provided a suitable geometric interpretation of the junction is given. We provide a precise statement of the BPS limit and force-balance property. At weak coupling and sufficiently dense limit, we argue that a (p,q) string embedded in the string network is a 'wiggly string', whose low-energy dynamics can be described via a renormalization group evolved, smooth effective non-relativistic string. We also suggest the possibility that, upon type IIB strings being promoted to the M-theory membrane, there can exist 'evanescent' bound-states at the triple junction in the continuum. (orig.)

  1. Quantitatively accurate calculations of conductance and thermopower of molecular junctions

    DEFF Research Database (Denmark)

    Markussen, Troels; Jin, Chengjun; Thygesen, Kristian Sommer

    2013-01-01

    Thermopower measurements of molecular junctions have recently gained interest as a characterization technique that supplements the more traditional conductance measurements. Here we investigate the electronic conductance and thermopower of benzenediamine (BDA) and benzenedicarbonitrile (BDCN...

  2. Majorana splitting from critical currents in Josephson junctions

    Science.gov (United States)

    Cayao, Jorge; San-Jose, Pablo; Black-Schaffer, Annica M.; Aguado, Ramón; Prada, Elsa

    2017-11-01

    A semiconducting nanowire with strong Rashba spin-orbit coupling and coupled to a superconductor can be tuned by an external Zeeman field into a topological phase with Majorana zero modes. Here we theoretically investigate how this exotic topological superconductor phase manifests in Josephson junctions based on such proximitized nanowires. In particular, we focus on critical currents in the short junction limit (LN≪ξ , where LN is the junction length and ξ is the superconducting coherence length) and show that they contain important information about nontrivial topology and Majoranas. This includes signatures of the gap inversion at the topological transition and a unique oscillatory pattern that originates from Majorana interference. Interestingly, this pattern can be modified by tuning the transmission across the junction, thus providing complementary evidence of Majoranas and their energy splittings beyond standard tunnel spectroscopy experiments, while offering further tunability by virtue of the Josephson effect.

  3. A case report of craniovertebral junction intradural extramedullary neurenteric cyst

    Directory of Open Access Journals (Sweden)

    Rajeshwari S Vhora

    2014-01-01

    Full Text Available A neurenteric cyst of the craniocervical (CV junction, as a cause of bulbomedullary compression, is very rare. An abnormal communication between the endoderm and neuroectoderm during the third week of embryogenesis may be responsible for its formation. It is a rare spinal condition. The most frequent location is at the lower cervical and higher thoracic spine. Neurenteric cysts of the craniocervical junction are even rarer. We report the case of a CV junction intradural neurenteric cyst. Magnetic Resonance Imaging (MRI of our patient demonstrated an intradural extramedullary process of the craniocervical junction. A surgical posterior approach allowed gross total resection of the lesion. The histopathology of the surgical specimen showed that the cyst wall was made up of fibrocollagen walls lined with a partially ciliated columnar epithelium.

  4. Photonic and Quantum Interactions of Atomic-Scale Junctions

    Data.gov (United States)

    National Aeronautics and Space Administration — In this proposal, the fundamental quantum and photonic interactions of bimetallic atomic-scale junctions (ASJs) will be explored, with three major space...

  5. Droplet Traffic Control at a simple T junction

    Science.gov (United States)

    Panizza, Pascal; Engl, Wilfried; Colin, Annie; Ajdari, Armand

    2006-03-01

    A basic yet essential element of every traffic flow control is the effect of a junction where the flow is separated into several streams. How do pedestrians, vehicles or blood cells divide when they reach a junction? How does the outcome depend on their density? Similar fundamental questions hold for much simpler systems: in this paper, we have studied the behaviour of periodic trains of water droplets flowing in oil through a channel as they reach a simple, locally symmetric, T junction. Depending on their dilution, we observe that the droplets are either alternately partitioned between both outlets or sorted exclusively into the shortest one. We show that this surprising behaviour results from the hydrodynamic feed-back of drops in the two outlets on the selection process occurring at the junction. Our results offer a first guide for the design and modelling of droplet traffic in complex branched networks, a necessary step towards parallelized droplet-based ``lab-on-chip'' devices.

  6. Mechanical break junctions: enormous information in a nanoscale package.

    Science.gov (United States)

    Natelson, Douglas

    2012-04-24

    Mechanical break junctions, particularly those in which a metal tip is repeatedly moved in and out of contact with a metal film, have provided many insights into electronic conduction at the atomic and molecular scale, most often by averaging over many possible junction configurations. This averaging throws away a great deal of information, and Makk et al. in this issue of ACS Nano demonstrate that, with both simulated and real experimental data, more sophisticated two-dimensional analysis methods can reveal information otherwise obscured in simple histograms. As additional measured quantities come into play in break junction experiments, including thermopower, noise, and optical response, these more sophisticated analytic approaches are likely to become even more powerful. While break junctions are not directly practical for useful electronic devices, they are incredibly valuable tools for unraveling the electronic transport physics relevant for ultrascaled nanoelectronics.

  7. Top 50 most-cited articles on craniovertebral junction surgery

    Directory of Open Access Journals (Sweden)

    Nima Alan

    2017-01-01

    Conclusion: Using citation analysis, we have provided a list of the most-cited articles representing important contributions of various authors from many institutions across the world to the field of craniovertebral junction surgery.

  8. Junction temperature estimation for an advanced active power cycling test

    DEFF Research Database (Denmark)

    Choi, Uimin; Blaabjerg, Frede; Jørgensen, S.

    2015-01-01

    estimation method using on-state VCE for an advanced active power cycling test is proposed. The concept of the advanced power cycling test is explained first. Afterwards the junction temperature estimation method using on-state VCE and current is presented. Further, the method to improve the accuracy...... of the maximum junction temperature estimation is also proposed. Finally, the validity and effectiveness of the proposed method is confirmed by experimental results.......On-state collector-emitter voltage (VCE) is a good indicator to determine the wear-out condition of power device modules. Further, it is a one of the Temperature Sensitive Electrical Parameters (TSEPs) and thus can be used for junction temperature estimation. In this paper, the junction temperature...

  9. Development of High Temperature Superconducting Josephson Junction Device Technology

    National Research Council Canada - National Science Library

    Myers, Kirsten

    1998-01-01

    The DuPont program was successful in generating useful knowledge about thallium cuprate materials, photoresist reflow processing, and radiant heater technology though it did not lead to a new junction technology...

  10. Bedrock Geologic Map of the Essex Junction Quadrangle, Vermont

    Data.gov (United States)

    Vermont Center for Geographic Information — Digital data from VG12-3, Gale, M., Kim. J., and Ruksznis, A., 2012, Bedrock Geologic Map of the essex Junction Quadrangle: Vermont Geological Survey Open File...

  11. Stentless pyeloplasty for ureteropelvic junction obstruction in children

    African Journals Online (AJOL)

    in patients with ureteropelvic junction (UPJ) obstruction. In all,. 42 patients ... of Urology, National Institute of Rehabilitation Medicine, Islamabad, Pakistan. Correspondence to ... stentless pyeloplasty in open, laparoscopic, and robotic- assisted ...

  12. Low-Cost Multi-Junction Photovoltaic Cells, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed SBIR project will provide a pathway to dramatically reduce the cost of multi-junction solar cells. The project leverages a TRL6 micropackaging process...

  13. High-efficiency thermal switch based on topological Josephson junctions

    Science.gov (United States)

    Sothmann, Björn; Giazotto, Francesco; Hankiewicz, Ewelina M.

    2017-02-01

    We propose theoretically a thermal switch operating by the magnetic-flux controlled diffraction of phase-coherent heat currents in a thermally biased Josephson junction based on a two-dimensional topological insulator. For short junctions, the system shows a sharp switching behavior while for long junctions the switching is smooth. Physically, the switching arises from the Doppler shift of the superconducting condensate due to screening currents induced by a magnetic flux. We suggest a possible experimental realization that exhibits a relative temperature change of 40% between the on and off state for realistic parameters. This is a factor of two larger than in recently realized thermal modulators based on conventional superconducting tunnel junctions.

  14. Towards quantum signatures in a swept-bias Josephson junction

    Energy Technology Data Exchange (ETDEWEB)

    Losert, Harald; Vogel, Karl; Schleich, Wolfgang P. [Institut fuer Quantenphysik and Center for Integrated Quantum Science and Technology (IQST), Universitaet Ulm, D-89069 Ulm (Germany)

    2016-07-01

    Josephson junctions are one of the best examples for the observation of macroscopic quantum tunneling. The phase difference in a current-biased Josephson junction behaves like the position of a particle in a tilted washboard potential. The escape of this phase-particle corresponds to the voltage switching of the associated junction. Quantum mechanically, the escape from the washboard potential can be explained as tunneling from the ground state, or an excited state. However, it has been shown, that in the case of periodic driving the experimental data for quantum mechanical key features, e.g. Rabi oscillations or energy level quantization, can be reproduced by a completely classical description. Motivated by this discussion, we investigate a swept-bias Josephson junction in the case of a large critical current. In particular, we contrast the switching current distributions resulting from a quantum mechanical and classical description of the time evolution.

  15. Resonant tunnel magnetoresistance in a double magnetic tunnel junction

    KAUST Repository

    Useinov, Arthur; Useinov, Niazbeck Kh H; Tagirov, Lenar R.; Kosel, Jü rgen

    2011-01-01

    We present quasi-classical approach to calculate a spin-dependent current and tunnel magnetoresistance (TMR) in double magnetic tunnel junctions (DMTJ) FML/I/FMW/I/FMR, where the magnetization of the middle ferromagnetic metal layer FMW can

  16. Niobium nitride Josephson tunnel junctions with magnesium oxide barriers

    International Nuclear Information System (INIS)

    Shoji, A.; Aoyagi, M.; Kosaka, S.; Shinoki, F.; Hayakawa, H.

    1985-01-01

    Niobium nitride-niobium nitride Josephson tunnel junctions have been fabricated using amorphous magnesium oxide (a-MgO) films as barriers. These junctions have excellent tunneling characteristics. For example, a large gap voltage (V/sub g/ = 5.1 mV), a large product of the maximum critical current and the normal tunneling resistance (I/sub c/R/sub n/ = 3.25 mV), and a small subgap leakage current (V/sub m/ = 45 mV, measured at 3 mV) have been obtained for a NbN/a-MgO/NbN junction. The critical current of this junction remains finite up to 14.5 K

  17. Robust spin transfer torque in antiferromagnetic tunnel junctions

    KAUST Repository

    Saidaoui, Hamed Ben Mohamed; Waintal, Xavier; Manchon, Aurelien

    2017-01-01

    We theoretically study the current-induced spin torque in antiferromagnetic tunnel junctions, composed of two semi-infinite antiferromagnetic layers separated by a tunnel barrier, in both clean and disordered regimes. We find that the torque

  18. ALTERNATIVE MATERIALS FOR RAMP-EDGE SNS JUNCTIONS

    International Nuclear Information System (INIS)

    Jia, Q.; Fan, Y.; Gim, Y.

    1999-01-01

    We report on the processing optimization and fabrication of ramp-edge high-temperature superconducting junctions by using alternative materials for both superconductor electrodes and normal-metal barrier. By using Ag-doped YBa 2 Cu 3 O 7-x (Ag:YBCO) as electrodes and a cation-modified compound of (Pr y Gd 0.6-y )Ca 0.4 Ba 1.6 La 0.4 Cu 3 O 7 (y = 0.4, 0.5, and 0.6) as a normal-metal barrier, high-temperature superconducting Josephson junctions have been fabricated in a ramp-edge superconductor/normal-metal/superconductor (SNS) configuration. By using Ag:YBCO as electrodes, we have found that the processing controllability /reproducibility and the stability of the SNS junctions are improved substantially. The junctions fabricated with these alternative materials show well-defined RSJ-like current vs voltage characteristics at liquid nitrogen temperature

  19. Systematic optimization of quantum junction colloidal quantum dot solar cells

    KAUST Repository

    Liu, Huan

    2012-01-01

    The recently reported quantum junction architecture represents a promising approach to building a rectifying photovoltaic device that employs colloidal quantum dot layers on each side of the p-n junction. Here, we report an optimized quantum junction solar cell that leverages an improved aluminum zinc oxide electrode for a stable contact to the n-side of the quantum junction and silver doping of the p-layer that greatly enhances the photocurrent by expanding the depletion region in the n-side of the device. These improvements result in greater stability and a power conversion efficiency of 6.1 under AM1.5 simulated solar illumination. © 2012 American Institute of Physics.

  20. Resonator coupled Josephson junctions; parametric excitations and mutual locking

    DEFF Research Database (Denmark)

    Jensen, H. Dalsgaard; Larsen, A.; Mygind, Jesper

    1991-01-01

    Self-pumped parametric excitations and mutual locking in systems of Josephson tunnel junctions coupled to multimode resonators are reported. For the very large values of the coupling parameter, obtained with small Nb-Al2O3-Nb junctions integrated in superconducting microstrip resonators, the DC I......-V characteristic shows an equidistant series of current steps generated by subharmonic pumping of the fundamental resonator mode. This is confirmed by measurement of frequency and linewidth of the emitted Josephson radiation...

  1. A rare presentation of lipoma on mandibular mucogingival junction

    Directory of Open Access Journals (Sweden)

    Gaurav Sharma

    2016-01-01

    Full Text Available Lipoma is the most common tumor of mesenchymal tissues of body, but its occurrence in oral cavity is infrequent. Buccal mucosa is the most common intraoral site of lipoma followed by tongue, floor of the mouth, and buccal vestibule. The involvement of mucogingival junction is rare. We present a unique case report of oral lipoma occurring on mandibular mucogingival junction with review of literature which has emphasis on differential diagnosis.

  2. Droplet Traffic at a Simple Junction at Low Capillary Numbers

    Science.gov (United States)

    Engl, Wilfried; Roche, Matthieu; Colin, Annie; Panizza, Pascal; Ajdari, Armand

    2005-11-01

    We report that, when a train of confined droplets flowing through a channel reaches a junction, the droplets either are alternately distributed between the different outlets or all collect into the shortest one. We argue that this behavior is due to the hydrodynamic feedback of droplets in the different outlets on the selection process occurring at the junction. A “mean field” model, yielding semiquantitative results, offers a first guide to predict droplet traffic in branched networks.

  3. Using ion irradiation to make high-Tc Josephson junctions

    International Nuclear Information System (INIS)

    Bergeal, N.; Lesueur, J.; Sirena, M.; Faini, G.; Aprili, M.; Contour, J. P.; Leridon, B.

    2007-01-01

    In this article we describe the effect of ion irradiation on high-T c superconductor thin film and its interest for the fabrication of Josephson junctions. In particular, we show that these alternative techniques allow to go beyond most of the limitations encountered in standard junction fabrication methods, both in the case of fundamental and technological purposes. Two different geometries are presented: a planar one using a single high-T c film and a mesa one defined in a trilayer structure

  4. Craniovertebral junction stenosis in Lenz-Majewski syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Mizuguchi, Koichi; Ishigro, Akira [National Center for Child Health and Development, Department of General Pediatrics and Interdisciplinary Medicine, Setagaya-ku, Tokyo (Japan); Miyazaki, Osamu [National Center for Child Health and Development, Department of Radiology, Tokyo (Japan); Nishimura, Gen [Tokyo Metropolitan Children' s Medical Center, Department of Pediatric Imaging, Tokyo (Japan)

    2015-09-15

    We report a girl with Lenz-Majewski syndrome associated with craniovertebral junction stenosis that led to communicating hydrocephalus and cervical myelopathy. The life-threatening complication was related to progressive craniovertebral hyperostosis that rapidly exacerbated during early childhood. Despite initial success of surgical intervention at 2 years of age, she developed apneic spells and died suddenly at age 5 years. Close monitoring for craniovertebral junction stenosis is essential to reduce morbidity and mortality in children with Lenz-Majewski syndrome. (orig.)

  5. US Department of Energy Grand Junction Projects Office Remedial Action Project. Final report of the decontamination and decommissioning of Building 52 at the Grand Junction Projects Office Facility

    International Nuclear Information System (INIS)

    Krabacher, J.E.

    1996-08-01

    The U.S. Department of Energy (DOE) Grand Junction Projects Office (GJPO) occupies a 61.7-acre facility along the Gunnison River near Grand Junction, Colorado. This site was contaminated with uranium ore and mill tailings during uranium refining activities of the Manhattan Engineer District and during pilot milling experiments conducted for the U.S. Atomic Energy Commission's domestic uranium procurement program. The DOE Defense Decontamination and Decommissioning Program established the GJPO Remedial Action Project to clean up and restore the facility lands, improvements, and the underlying aquifer. The site contractor for the facility, Rust Geotech, also was the remedial action contractor. Building 52 was found to be radiologically contaminated and was demolished in 1994. The soil area within the footprint of the building has been remediated in accordance with the identified standards and the area can be released for unlimited exposure and unrestricted use. This document was prepared in response to a DOE request for an individual final report for each contaminated GJPO building

  6. Entropy Flow Through Near-Critical Quantum Junctions

    Science.gov (United States)

    Friedan, Daniel

    2017-05-01

    This is the continuation of Friedan (J Stat Phys, 2017. doi: 10.1007/s10955-017-1752-8). Elementary formulas are derived for the flow of entropy through a circuit junction in a near-critical quantum circuit close to equilibrium, based on the structure of the energy-momentum tensor at the junction. The entropic admittance of a near-critical junction in a bulk-critical circuit is expressed in terms of commutators of the chiral entropy currents. The entropic admittance at low frequency, divided by the frequency, gives the change of the junction entropy with temperature—the entropic "capacitance". As an example, and as a check on the formalism, the entropic admittance is calculated explicitly for junctions in bulk-critical quantum Ising circuits (free fermions, massless in the bulk), in terms of the reflection matrix of the junction. The half-bit of information capacity per end of critical Ising wire is re-derived by integrating the entropic "capacitance" with respect to temperature, from T=0 to T=∞.

  7. Anchored PKA as a gatekeeper for gap junctions.

    Science.gov (United States)

    Pidoux, Guillaume; Taskén, Kjetil

    2015-01-01

    Anchored protein kinase A (PKA) bound to A Kinase Anchoring Protein (AKAP) mediates effects of localized increases in cAMP in defined subcellular microdomains and retains the specificity in cAMP-PKA signaling to distinct extracellular stimuli. Gap junctions are pores between adjacent cells constituted by connexin proteins that provide means of communication and transfer of small molecules. While the PKA signaling is known to promote human trophoblast cell fusion, the gap junction communication through connexin 43 (Cx43) is a prerequisite for this process. We recently demonstrated that trophoblast fusion is regulated by ezrin, a known AKAP, which binds to Cx43 and delivers PKA in the vicinity gap junctions. We found that disruption of the ezrin-Cx43 interaction abolished PKA-dependent phosphorylation of Cx43 as well as gap junction communication and subsequently cell fusion. We propose that the PKA-ezrin-Cx43 macromolecular complex regulating gap junction communication constitutes a general mechanism to control opening of Cx43 gap junctions by phosphorylation in response to cAMP signaling in various cell types.

  8. What happens in Josephson junctions at high critical current densities

    Science.gov (United States)

    Massarotti, D.; Stornaiuolo, D.; Lucignano, P.; Caruso, R.; Galletti, L.; Montemurro, D.; Jouault, B.; Campagnano, G.; Arani, H. F.; Longobardi, L.; Parlato, L.; Pepe, G. P.; Rotoli, G.; Tagliacozzo, A.; Lombardi, F.; Tafuri, F.

    2017-07-01

    The impressive advances in material science and nanotechnology are more and more promoting the use of exotic barriers and/or superconductors, thus paving the way to new families of Josephson junctions. Semiconducting, ferromagnetic, topological insulator and graphene barriers are leading to unconventional and anomalous aspects of the Josephson coupling, which might be useful to respond to some issues on key problems of solid state physics. However, the complexity of the layout and of the competing physical processes occurring in the junctions is posing novel questions on the interpretation of their phenomenology. We classify some significant behaviors of hybrid and unconventional junctions in terms of their first imprinting, i.e., current-voltage curves, and propose a phenomenological approach to describe some features of junctions characterized by relatively high critical current densities Jc. Accurate arguments on the distribution of switching currents will provide quantitative criteria to understand physical processes occurring in high-Jc junctions. These notions are universal and apply to all kinds of junctions.

  9. Affordance-based individuation of junctions in Open Street Map

    Directory of Open Access Journals (Sweden)

    Simon Scheider

    2012-06-01

    Full Text Available We propose an algorithm that can be used to identify automatically the subset of street segments of a road network map that corresponds to a junction. The main idea is to use turn-compliant locomotion affordances, i.e., restricted patterns of supported movement, in order to specify junctions independently of their data representation, and in order to motivate tractable individuation and classification strategies. We argue that common approaches based solely on geometry or topology of the street segment graph are useful but insufficient proxies. They miss certain turn restrictions essential to junctions. From a computational viewpoint, the main challenge of affordance-based individuation of junctions lies in its complex recursive definition. In this paper, we show how Open Street Map data can be interpreted into locomotion affordances, and how the recursive junction definition can be translated into a deterministic algorithm. We evaluate this algorithm by applying it to small map excerpts in order to delineate the contained junctions.

  10. Simulations of signal amplification and oscillations using a SNS junction

    International Nuclear Information System (INIS)

    Luiz, A.M.; Soares, V.; Nicolsky, R.

    1998-01-01

    A superconducting - normal metal - superconducting junction (SNS junction) may exhibit a low voltage negative differential resistance (LVNDR) effect over part of its current voltage characteristic (CVC). As the LVNDR effect is stable against a bias voltage at this CVC range, it should be possible to combine a SNS junction with conventional electronic circuits to obtain electronic devices such as mixers, amplifiers and oscillators. Making use of this remarkable effect, we show that an amplifier may be feasible by assembling a simple voltage divider made up of a SNS junction in series with a resistor. The amplifier circuit includes an adjustable DC voltage supply (the bias voltage) and an AC signal source with a given voltage. The SNS junction is connected in series with a resistor R. Choosing values of the load resistance R approximately equal to the module of the negative differential resistance (dV/dI), at the bias voltage, we may obtain large gains in this amplifier device. In order to get an oscillator, the SNS junction should be connected to a RLC tank circuit with a bias voltage adjusted in the range of the LVNDR region of its CVC. A power output of the order of one microwatt may be easily obtained. (orig.)

  11. Intraepithelial lymphocytes express junctional molecules in murine small intestine

    International Nuclear Information System (INIS)

    Inagaki-Ohara, Kyoko; Sawaguchi, Akira; Suganuma, Tatsuo; Matsuzaki, Goro; Nawa, Yukifumi

    2005-01-01

    Intestinal intraepithelial lymphocytes (IEL) that reside at basolateral site regulate the proliferation and differentiation of epithelial cells (EC) for providing a first line of host defense in intestine. However, it remains unknown how IEL interact and communicate with EC. Here, we show that IEL express junctional molecules like EC. We identified mRNA expression of the junctional molecules in IEL such as zonula occludens (ZO)-1, occludin and junctional adhesion molecule (JAM) (tight junction), β-catenin and E-cadherin (adherens junction), and connexin26 (gap junction). IEL constitutively expressed occludin and E-cadherin at protein level, while other T cells in the thymus, spleen, liver, mesenteric lymph node, and Peyer's patches did not. γδ IEL showed higher level of these expressions than αβ IEL. The expression of occludin was augmented by anti-CD3 Ab stimulation. These results suggest the possibility of a novel role of IEL concerning epithelial barrier and communication between IEL and EC

  12. Regulation of Tight Junctions in Upper Airway Epithelium

    Directory of Open Access Journals (Sweden)

    Takashi Kojima

    2013-01-01

    Full Text Available The mucosal barrier of the upper respiratory tract including the nasal cavity, which is the first site of exposure to inhaled antigens, plays an important role in host defense in terms of innate immunity and is regulated in large part by tight junctions of epithelial cells. Tight junction molecules are expressed in both M cells and dendritic cells as well as epithelial cells of upper airway. Various antigens are sampled, transported, and released to lymphocytes through the cells in nasal mucosa while they maintain the integrity of the barrier. Expression of tight junction molecules and the barrier function in normal human nasal epithelial cells (HNECs are affected by various stimuli including growth factor, TLR ligand, and cytokine. In addition, epithelial-derived thymic stromal lymphopoietin (TSLP, which is a master switch for allergic inflammatory diseases including allergic rhinitis, enhances the barrier function together with an increase of tight junction molecules in HNECs. Furthermore, respiratory syncytial virus infection in HNECs in vitro induces expression of tight junction molecules and the barrier function together with proinflammatory cytokine release. This paper summarizes the recent progress in our understanding of the regulation of tight junctions in the upper airway epithelium under normal, allergic, and RSV-infected conditions.

  13. Dynamics of fractional vortices in long Josephson junctions

    International Nuclear Information System (INIS)

    Gaber, Tobias

    2007-01-01

    In this thesis static and dynamic properties of fractional vortices in long Josephson junctions are investigated. Fractional vortices are circulating supercurrents similar to the well-known Josephson fluxons. Yet, they show the distinguishing property of carrying only a fraction of the magnetic flux quantum. Fractional vortices are interesting non-linear objects. They spontaneously appear and are pinned at the phase discontinuity points of so called 0-κ junctions but can be bend or flipped by external forces like bias currents or magnetic fields. 0-κ junctions and fractional vortices are generalizations of the well-known 0-π junctions and semifluxons, where not only phase jumps of pi but arbitrary values denoted by kappa are considered. By using so-called artificial 0-κ junctions that are based on standard Nb-AlO x -Nb technology the classical dynamics of fractional vortices has been investigated experimentally for the very first time. Here, half-integer zero field steps could be observed. These voltage steps on the junction's current-voltage characteristics correspond to the periodic flipping/hopping of fractional vortices. In addition, the oscillatory eigenmodes of fractional vortices were investigated. In contrast to fluxons fractional vortices have an oscillatory eigenmode with a frequency within the plasma gap. Using resonance spectroscopy the dependence of the eigenmode frequency on the flux carried by the vortex and an applied bias current was determined. (orig.)

  14. The string-junction picture of multiquark states: an update

    Energy Technology Data Exchange (ETDEWEB)

    Rossi, G.C. [Dipartimento di Fisica, Università di Roma Tor Vergata, INFN, Sezione di Roma 2, Via della Ricerca Scientifica, 00133 Roma (Italy); Centro Fermi, Museo Storico della Fisica,Piazza del Viminale 1, 00184 Roma (Italy); Veneziano, G. [Collège de France,11 place M. Berthelot, 75005 Paris (France); Theory Division, CERN,CH-1211 Geneva 23 (Switzerland); Dipartimento di Fisica, Università di Roma La Sapienza,Piazzale A. Moro 5, 00185 Roma (Italy)

    2016-06-07

    We recall and update, both theoretically and phenomenologically, our (nearly) forty-years-old proposal of a string-junction as a necessary complement to the conventional classification of hadrons based just on their quark-antiquark constituents. In that proposal single (though in general metastable) hadronic states are associated with “irreducible' gauge-invariant operators consisting of Wilson lines (visualized as strings of color flux tubes) that may either end on a quark or an antiquark, or annihilate in triplets at a junction J or an anti-junction J̄. For the junction-free sector (ordinary q q̄ mesons and glueballs) the picture is supported by large-N (number of colors) considerations as well as by a lattice strong-coupling expansion. Both imply the famous OZI rule suppressing quark-antiquark annihilation diagrams. For hadrons with J and/or J̄ constituents the same expansions support our proposal, including its generalization of the OZI rule to the suppression of J−J̄ annihilation diagrams. Such a rule implies that hadrons with junctions are “mesophobic' and thus unusually narrow if they are below threshold for decaying into as many baryons as their total number of junctions (two for a tetraquark, three for a pentaquark). Experimental support for our claim, based on the observation that narrow multiquark states typically lie below (well above) the relevant baryonic (mesonic) thresholds, will be presented.

  15. Heat Transport in Graphene Ferromagnet-Insulator-Superconductor Junctions

    Institute of Scientific and Technical Information of China (English)

    LI Xiao-Wei

    2011-01-01

    We study heat transport in a graphene ferromagnet-insulator-superconducting junction. It is found that the thermal conductance of the graphene ferromagnet-insulator-superconductor (FIS) junction is an oscillatory function of the barrier strength x in the thin-barrier limit. The gate potential U0 decreases the amplitude of thermal conductance oscillation. Both the amplitude and phase of the thermal conductance oscillation varies with the exchange energy Eh. The thermal conductance of a graphene FIS junction displays the usual exponential dependence on temperature, reflecting the s-wave symmetry of superconducting graphene.%@@ We study heat transport in a graphene ferromagnet-insulator-superconducting junction.It is found that the thermal conductance of the graphene ferromagnet-insulator-superconductor(FIS)junction is an oscillatory function of the barrier strength X in the thin-barrier limit.The gate potential Uo decreases the amplitude of thermal conductance oscillation.Both the amplitude and phase of the thermal conductance oscillation varies with the exchange energy Eh.The thermal conductance of a graphene FIS junction displays the usual exponential dependence on temperature, reflecting the s-wave symmetry of superconducting graphene.

  16. STIM proteins and the endoplasmic reticulum-plasma membrane junctions.

    Science.gov (United States)

    Carrasco, Silvia; Meyer, Tobias

    2011-01-01

    Eukaryotic organelles can interact with each other through stable junctions where the two membranes are kept in close apposition. The junction that connects the endoplasmic reticulum to the plasma membrane (ER-PM junction) is unique in providing a direct communication link between the ER and the PM. In a recently discovered signaling process, STIM (stromal-interacting molecule) proteins sense a drop in ER Ca(2+) levels and directly activate Orai PM Ca(2+) channels across the junction space. In an inverse process, a voltage-gated PM Ca(2+) channel can directly open ER ryanodine-receptor Ca(2+) channels in striated-muscle cells. Although ER-PM junctions were first described 50 years ago, their broad importance in Ca(2+) signaling, as well as in the regulation of cholesterol and phosphatidylinositol lipid transfer, has only recently been realized. Here, we discuss research from different fields to provide a broad perspective on the structures and unique roles of ER-PM junctions in controlling signaling and metabolic processes.

  17. Proposed differential-frequency-readout system by hysteretic Josephson junctions

    International Nuclear Information System (INIS)

    Wang, L.Z.; Duncan, R.V.

    1992-01-01

    The Josephson relation V=nhν/2e has been verified experimentally to 3 parts in 10 19 [A. K. Jain, J. E. Lukens, and J.-S. Tsai, Phys. Rev. Lett. 58, 1165 (1987)]. Motivated by this result, we propose a differential-frequency-readout system by two sets of hysteretic Josephson junctions rf biased at millimeter wavelengths. Because of the Josephson relation, the proposed differential-frequency-readout system is not limited by photon fluctuation, which limits most photon-detection schemes. In the context of the Stewart-McCumber model [W. C. Stewart, Appl. Phys. Lett. 12, 277 (1968); D. E. McCumber, J. Appl. Phys. 39, 3113 (1968)] of Josephson junctions, we show theoretically that the differential frequency of the two milliwave biases can be read out by the proposed system to unprecedented accuracy. The stability of the readout scheme is also discussed. The measurement uncertainty of the readout system resulting from the intrinsic thermal noise in the hysteretic junctions is shown to be insignificant. The study of two single junctions can be extended to two sets of Josephson junctions connected in series (series array) in this measurement scheme provided that junctions are separated by at least 10 μm [D. W. Jillie, J. E. Lukens, and Y. H. Kao, Phys. Rev. Lett. 38, 915 (1977)]. The sensitivity for the differential frequency detection may be increased by biasing both series arrays to a higher constant-voltage step

  18. Role of the Adherens Junction Protein Fascin in the Regulation of Tight Junction Permeability in the Mouse Mammary Gland

    National Research Council Canada - National Science Library

    Beeman, Neal

    2001-01-01

    .... Transduced cells are morphologically normal and produce milk. This gene delivery system was used to express an N-terminally truncated mutant of the tight junction protein occluding in the mammary gland and in cultured cells...

  19. Structural Molecular Components of Septate Junctions in Cnidarians Point to the Origin of Epithelial Junctions in Eukaryotes

    KAUST Repository

    Ganot, P.; Zoccola, D.; Tambutte, E.; Voolstra, Christian R.; Aranda, Manuel; Allemand, D.; Tambutte, S.

    2014-01-01

    Septate junctions (SJs) insure barrier properties and control paracellular diffusion of solutes across epithelia in invertebrates. However, the origin and evolution of their molecular constituents in Metazoa have not been firmly established. Here

  20. Spatial inhomogeneous barrier heights at graphene/semiconductor Schottky junctions

    Science.gov (United States)

    Tomer, Dushyant

    Graphene, a semimetal with linear energy dispersion, forms Schottky junction when interfaced with a semiconductor. This dissertation presents temperature dependent current-voltage and scanning tunneling microscopy/spectroscopy (STM/S) measurements performed on graphene Schottky junctions formed with both three and two dimensional semiconductors. To fabricate Schottky junctions, we transfer chemical vapor deposited monolayer graphene onto Si- and C-face SiC, Si, GaAs and MoS2 semiconducting substrates using polymer assisted chemical method. We observe three main type of intrinsic spatial inhomogeneities, graphene ripples, ridges and semiconductor steps in STM imaging that can exist at graphene/semiconductor junctions. Tunneling spectroscopy measurements reveal fluctuations in graphene Dirac point position, which is directly related to the Schottky barrier height. We find a direct correlation of Dirac point variation with the topographic undulations of graphene ripples at the graphene/SiC junction. However, no such correlation is established at graphene/Si and Graphene/GaAs junctions and Dirac point variations are attributed to surface states and trapped charges at the interface. In addition to graphene ripples and ridges, we also observe atomic scale moire patterns at graphene/MoS2 junction due to van der Waals interaction at the interface. Periodic topographic modulations due to moire pattern do not lead to local variation in graphene Dirac point, indicating that moire pattern does not contribute to fluctuations in electronic properties of the heterojunction. We perform temperature dependent current-voltage measurements to investigate the impact of topographic inhomogeneities on electrical properties of the Schottky junctions. We observe temperature dependence in junction parameters, such as Schottky barrier height and ideality factor, for all types of Schottky junctions in forward bias measurements. Standard thermionic emission theory which assumes a perfect

  1. Vortex dynamics in Josephson junctions arrays

    International Nuclear Information System (INIS)

    Shalom, Diego Edgar

    2005-01-01

    In this work we study the dynamics of vortices in two-dimensional overdamped Josephson Junctions Arrays (JJA) driven by dc current in a wide range of conditions varying magnetic field and temperature using experiments, numerical simulations and analytic studies.We develop the Fixed Phase method, a variation of numeric relaxation techniques in which we fix and control the phase of some islands, adjacent to the vortex center, while allowing all other phases in the system to relax.In this way we are able to pull and push the vortex uphill, as we are forcing the center of rotation of the vortex currents to be in a defined location, allowing us to calculate the potential energy of a vortex located in any arbitrary position.We use this method to study the potential energy of a vortex in a variety of situations in homogeneous and non-homogeneous JJA, such as arrays with defects, channel arrays and ratchets.We study the finite size effects in JJA by means of analytic and numerical tools.We implement the rings model, in which we replace the two-dimensional square array by a series of square, concentric, uncoupled rings. This is equivalent to disregarding the radial junctions that couple consecutive rings.In spite of its extreme simplicity, this model holds the main ingredients of the magnetic dependence of the energy.We combine this model with other terms that take into account the dependence in the position of the vortex to obtain a general expression for the potential energy of a vortex in a finite JJA with applied magnetic field.We also present an expression for the first critical field, corresponding to the value of the magnetic field in which the entrance of the first vortex becomes energetically favorable.We build and study JJA modulated to form periodic and asymmetrical potentials for the vortices, named ratchet potentials.The experimental results clearly show the existence of a rectification in the motion of vortices in these potentials.Under certain conditions we

  2. Syringomyelia and Craniocervical Junction Abnormalities in Chihuahuas.

    Science.gov (United States)

    Kiviranta, A-M; Rusbridge, C; Laitinen-Vapaavuori, O; Hielm-Björkman, A; Lappalainen, A K; Knowler, S P; Jokinen, T S

    2017-11-01

    Chiari-like malformation (CM) and syringomyelia (SM) are widely reported in Cavalier King Charles Spaniels and Griffon Bruxellois dogs. Increasing evidence indicates that CM and SM also occur in other small and toy breed dogs, such as Chihuahuas. To describe the presence of SM and craniocervical junction (CCJ) abnormalities in Chihuahuas and to evaluate the possible association of CCJ abnormalities with SM. To describe CM/SM-related clinical signs and neurologic deficits and to investigate the association of CM/SM-related clinical signs with signalment, SM, or CCJ abnormalities. Fifty-three client-owned Chihuahuas. Prospective study. Questionnaire analyses and physical and neurologic examinations were obtained before magnetic resonance and computed tomography imaging. Images were evaluated for the presence of SM, CM, and atlantooccipital overlapping. Additionally, medullary kinking, dorsal spinal cord compression, and their sum indices were calculated. Scratching was the most common CM/SM-related clinical sign and decreased postural reaction the most common neurologic deficit in 73 and 87% of dogs, respectively. Chiari-like malformation and SM were present in 100 and 38% of dogs, respectively. Syringomyelia was associated with the presence of CM/SM-related clinical signs (P = 0.034), and medullary kinking and sum indices were higher in dogs with clinical signs (P = 0.016 and P = 0.007, respectively). Syringomyelia and CCJ abnormalities are prevalent in Chihuahuas. Syringomyelia was an important factor for the presence of CM/SM-related clinical signs, but many dogs suffered from similar clinical signs without being affected by SM, highlighting the clinical importance of CCJ abnormalities in Chihuahuas. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  3. Regional instability following cervicothoracic junction surgery.

    Science.gov (United States)

    Steinmetz, Michael P; Miller, Jared; Warbel, Ann; Krishnaney, Ajit A; Bingaman, William; Benzel, Edward C

    2006-04-01

    The cervicothoracic junction (CTJ) is the transitional region between the cervical and thoracic sections of the spinal axis. Because it is a transitional zone between the mobile lordotic cervical and rigid kyphotic thoracic spines, the CTJ is a region of potential instability. This potential for instability may be exaggerated by surgical intervention. A retrospective review of all patients who underwent surgery involving the CTJ in the Department of Neurosurgery at the Cleveland Clinic Foundation during a 5-year period was performed. The CTJ was strictly defined as encompassing the C-7 vertebra and C7-T1 disc interspace. Patients were examined after surgery to determine if treatment had failed. Failure was defined as construct failure, deformity (progression or de novo), or instability. Variables possibly associated with treatment failure were analyzed. Statistical comparisons were performed using the Fisher exact test. Between January 1998 and November 2003, 593 CTJ operations were performed. Treatment failed in 14 patients. Of all variables studied, failure was statistically associated with laminectomy and multilevel ventral corpectomies with fusion across the CTJ. Other factors statistically associated with treatment failure included histories of cervical surgery, tobacco use, and surgery for the correction of deformity. The CTJ is a vulnerable region, and this vulnerability is exacerbated by surgery. Results of the present study indicate that laminectomy across the CTJ should be supplemented with instrumentation (and fusion). Multilevel ventral corpectomies across the CTJ should also be supplemented with dorsal instrumentation. Supplemental instrumentation should be considered for patients who have undergone prior cervical surgery, have a history of tobacco use, or are undergoing surgery for deformity correction.

  4. The influence of junction conformation on RNA cleavage by the hairpin ribozyme in its natural junction form.

    Science.gov (United States)

    Thomson, J B; Lilley, D M

    1999-01-01

    In the natural form of the hairpin ribozyme the two loop-carrying duplexes that comprise the majority of essential bases for activity form two adjacent helical arms of a four-way RNA junction. In the present work we have manipulated the sequence around the junction in a way known to perturb the global folding properties. We find that replacement of the junction by a different sequence that has the same conformational properties as the natural sequence gives closely similar reaction rate and Arrhenius activation energy for the substrate cleavage reaction. By comparison, rotation of the natural sequence in order to alter the three-dimensional folding of the ribozyme leads to a tenfold reduction in the kinetics of cleavage. Replacement with the U1 four-way junction that is resistant to rotation into the antiparallel structure required to allow interaction between the loops also gives a tenfold reduction in cleavage rate. The results indicate that the conformation of the junction has a major influence on the catalytic activity of the ribozyme. The results are all consistent with a role for the junction in the provision of a framework by which the loops are presented for interaction in order to create the active form of the ribozyme. PMID:10024170

  5. Prediction of static friction coefficient in rough contacts based on the junction growth theory

    Science.gov (United States)

    Spinu, S.; Cerlinca, D.

    2017-08-01

    The classic approach to the slip-stick contact is based on the framework advanced by Mindlin, in which localized slip occurs on the contact area when the local shear traction exceeds the product between the local pressure and the static friction coefficient. This assumption may be too conservative in the case of high tractions arising at the asperities tips in the contact of rough surfaces, because the shear traction may be allowed to exceed the shear strength of the softer material. Consequently, the classic frictional contact model is modified in this paper so that gross sliding occurs when the junctions formed between all contacting asperities are independently sheared. In this framework, when the contact tractions, normal and shear, exceed the hardness of the softer material on the entire contact area, the material of the asperities yields and the junction growth process ends in all contact regions, leading to gross sliding inception. This friction mechanism is implemented in a previously proposed numerical model for the Cattaneo-Mindlin slip-stick contact problem, which is modified to accommodate the junction growth theory. The frictionless normal contact problem is solved first, then the tangential force is gradually increased, until gross sliding inception. The contact problems in the normal and in the tangential direction are successively solved, until one is stabilized in relation to the other. The maximum tangential force leading to a non-vanishing stick area is the static friction force that can be sustained by the rough contact. The static friction coefficient is eventually derived as the ratio between the latter friction force and the normal force.

  6. Numerical prediction of pressure loss of fluid in a T-junction

    OpenAIRE

    Mohammed Abdulwahhab, Niranjan Kumar Injeti, Sadoun Fahad Dakhi

    2013-01-01

    This work presents a prediction of pressure loss of fluid with turbulent incompressible flow through a 90° tee junction was carried out and compared with analytical and experimental results. One turbulence model was used in the numerical simulations: k-ε model for two different values of area ratio between the main pipe and the branch pipe were 1.0 and 4.0, and flow rate ratios. The continuity, momentum and energy equations were discredited by means of a finite volume technique and the SIMPLE...

  7. A transimpedance amplifier for excess noise measurements of high junction capacitance avalanche photodiodes

    International Nuclear Information System (INIS)

    Green, James E; David, John P R; Tozer, Richard C

    2012-01-01

    This paper reports a novel and versatile system for measuring excess noise and multiplication in avalanche photodiodes (APDs), using a bipolar junction transistor based transimpedance amplifier front-end and based on phase-sensitive detection, which permits accurate measurement in the presence of a high dark current. The system can reliably measure the excess noise factor of devices with capacitance up to 5 nF. This system has been used to measure thin, large area Si pin APDs and the resulting data are in good agreement with measurements of the same devices obtained from a different noise measurement system which will be reported separately. (paper)

  8. Strain mapping near a triple junction in strained Ni-based alloy using EBSD and biaxial nanogauges

    Energy Technology Data Exchange (ETDEWEB)

    Clair, A. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Foucault, M.; Calonne, O. [Areva ANP, Centre Technique Departement Corrosion-Chimie, 30 Bd de l' industrie, BP 181, 71205 Le Creusot (France); Lacroute, Y.; Markey, L.; Salazar, M.; Vignal, V. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France); Finot, E., E-mail: Eric.Finot@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 5209 CNRS, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47870, 21078 Dijon Cedex (France)

    2011-05-15

    Research highlights: > Surface strains measured using nanogauge were compared to the texture obtained by EBSD. > Statistics of the principal strain discern the grains according to the Schmid factor. > Strain hotspots were localized near a triple junction of alloy 600 under tensile loading. > Asymetrical profile of the GB strains is a criterion for surface cracking initiation. - Abstract: A key element for analyzing the crack initiation in strained polycrystalline alloys is the local quantification of the surface strain distribution according to the grain texture. Using electron backscattered diffraction, the local microstructure was determined to both localize a triple junction and deduce the local Schmid factors. Kernel average misorientation (KAM) was also used to map the areas of defect concentration. The maximum principal strain and the in-plane shear strain were quantified using the biaxial nanogauge. Distortions of the array of nanodots used as spot markers were analyzed near the triple junction. The crystallographic orientation and the surface strain were then investigated both statistically for each grain and locally at the grain boundaries. The superimposition of microstructure and strain maps allows the high strain gradient (reaching 3-fold the applied strain) to be localized at preferential grain boundaries near the triple junction. The Schmid factors and the KAM were compared to the maximum principal strain and the in-plane shear strain respectively. The polycrystalline deformation was attributable first to the rotation of some grains, followed by the elongation of all grains along their preferential activated slip systems.

  9. Effect of Mefloquine, a Gap Junction Blocker, on Circadian Period2 Gene Oscillation in the Mouse Suprachiasmatic Nucleus

    Directory of Open Access Journals (Sweden)

    Jinmi Koo

    2015-09-01

    Full Text Available BackgroundIn mammals, the master circadian pacemaker is localized in an area of the ventral hypothalamus known as the suprachiasmatic nucleus (SCN. Previous studies have shown that pacemaker neurons in the SCN are highly coupled to one another, and this coupling is crucial for intrinsic self-sustainability of the SCN central clock, which is distinguished from peripheral oscillators. One plausible mechanism underlying the intercellular communication may involve direct electrical connections mediated by gap junctions.MethodsWe examined the effect of mefloquine, a neuronal gap junction blocker, on circadian Period 2 (Per2 gene oscillation in SCN slice cultures prepared from Per2::luciferase (PER2::LUC knock-in mice using a real-time bioluminescence measurement system.ResultsAdministration of mefloquine causes instability in the pulse period and a slight reduction of amplitude in cyclic PER2::LUC expression. Blockade of gap junctions uncouples PER2::LUC-expressing cells, in terms of phase transition, which weakens synchrony among individual cellular rhythms.ConclusionThese findings suggest that neuronal gap junctions play an important role in synchronizing the central pacemaker neurons and contribute to the distinct self-sustainability of the SCN master clock.

  10. RELAP-7 Progress Report: A Mathematical Model for 1-D Compressible, Single-Phase Flow Through a Branching Junction

    Energy Technology Data Exchange (ETDEWEB)

    Berry, R. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-08-14

    In the literature, the abundance of pipe network junction models, as well as inclusion of dissipative losses between connected pipes with loss coefficients, has been treated using the incompressible flow assumption of constant density. This approach is fundamentally, physically wrong for compressible flow with density change. This report introduces a mathematical modeling approach for general junctions in piping network systems for which the transient flows are compressible and single-phase. The junction could be as simple as a 1-pipe input and 1-pipe output with differing pipe cross-sectional areas for which a dissipative loss is necessary, or it could include an active component, between an inlet pipe and an outlet pipe, such as a pump or turbine. In this report, discussion will be limited to the former. A more general branching junction connecting an arbitrary number of pipes with transient, 1-D compressible single-phase flows is also presented. These models will be developed in a manner consistent with the use of a general equation of state like, for example, the recent Spline-Based Table Look-up method [1] for incorporating the IAPWS-95 formulation [2] to give accurate and efficient calculations for properties for water and steam with RELAP-7 [3].

  11. "Warming yang and invigorating qi" acupuncture alters acetylcholine receptor expression in the neuromuscular junction of rats with experimental autoimmune myasthenia gravis

    Directory of Open Access Journals (Sweden)

    Hai-peng Huang

    2016-01-01

    Full Text Available Myasthenia gravis is an autoimmune disorder in which antibodies have been shown to form against the nicotinic acetylcholine nicotinic postsynaptic receptors located at the neuromuscular junction. "Warming yang and invigorating qi" acupuncture treatment has been shown to reduce serum inflammatory cytokine expression and increase transforming growth factor beta expression in rats with experimental autoimmune myasthenia gravis. However, few studies have addressed the effects of this type of acupuncture on the acetylcholine receptors at the neuromuscular junction. Here, we used confocal laser scanning microscopy to examine the area and density of immunoreactivity for an antibody to the nicotinic acetylcholine receptor at the neuromuscular junction in the phrenic nerve of rats with experimental autoimmune myasthenia gravis following "warming yang and invigorating qi" acupuncture therapy. Needles were inserted at acupressure points Shousanli (LI10, Zusanli (ST36, Pishu (BL20, and Shenshu (BL23 once daily for 7 consecutive days. The treatment was repeated after 1 day of rest. We found that area and the integrated optical density of the immunoreactivity for the acetylcholine receptor at the neuromuscular junction of the phrenic nerve was significantly increased following acupuncture treatment. This outcome of the acupuncture therapy was similar to that of the cholinesterase inhibitor pyridostigmine bromide. These findings suggest that "warming yang and invigorating qi" acupuncture treatment increases acetylcholine receptor expression at the neuromuscular junction in a rat model of autoimmune myasthenia gravis.

  12. Capacitance measurement of Josephson tunnel junctions with microwave-induced dc quasiparticle tunneling currents

    International Nuclear Information System (INIS)

    Hamasaki, K.; Yoshida, K.; Irie, F.; Enpuku, K.

    1982-01-01

    The microwave response of the dc quasiparticle tunneling current in Josephson tunnel junctions, where the Josephson current is suppressed by an external magnetic field, has been studied quantitatively in order to clarify its characteristics as a probe for the measurement of the junction capacitance. Extensive experiments for both small and long junctions are carried out for distinguishing between microwave behaviors of lumped and distributed constant junctions. It is shown that the observed voltage dependence of the dc quasiparticle tunneling current modified by an applied rf field is in good agreement with a theoretical result which takes into account the influence of the microwave circuit connected to the junction. The comparison between theory and experiment gives the magnitude of the internal rf field in the junction. Together with the applied rf field, this internal rf field leads to the junction rf impedance which is dominated by the junction capacitance in our experimental condition. In the case of lumped junctions, this experimental rf impedance is in reasonable agreement with the theoretical one with the junction capacitance estimated from the Fiske step of the distributed junction fabricated on the same substrate; the obtained ratio of the experimental impedance to the theoretical one is approximately 0.6--1.7. In the case of distributed junctions, however, experimental values of their characteristic impedances are approximately 0.2--0.3 of theoretical values calculated by assuming the one-dimensional junction model and taking account of the standing-wave effect in the junction

  13. Engineering assessment of inactive uranium mill tailings, Grand Junction site, Grand Junction, Colorado. A summary of the Phase II, Title I

    International Nuclear Information System (INIS)

    1977-10-01

    Ford, Bacon and Davis Utah Inc. has performed an engineering assessment of the problems resulting from the existence of radioactive uranium mill tailings at Grand Junction, Colorado. The Phase II, Title I services include the preparation of topographic maps, the performance of core drillings and radiometric measurements sufficient to determine areas and volumes of tailings and radiation exposures of individuals and nearby populations, the investigation of site hydrology and meteorology, and the evaluation and costing of alternative corrective actions. Radon gas release from the 1.9 million tons of tailings at the Grand Junction site constitutes the most significant environmental impact, although windblown tailings and external gamma radiation are also factors. The eight alternative actions presented range from millsite decontamination (Option I), to adding various depths of stabilization cover material (Options II and III), to removal of the tailings to long-term storage sites and decontamination of the present site (Options IV through VIII). Cost estimates for the eight options range from $470,000 to $18,130,000. Reprocessing the tailings for uranium recovery does not appear to be economically attractive at present

  14. Au nanowire junction breakup through surface atom diffusion

    Science.gov (United States)

    Vigonski, Simon; Jansson, Ville; Vlassov, Sergei; Polyakov, Boris; Baibuz, Ekaterina; Oras, Sven; Aabloo, Alvo; Djurabekova, Flyura; Zadin, Vahur

    2018-01-01

    Metallic nanowires are known to break into shorter fragments due to the Rayleigh instability mechanism. This process is strongly accelerated at elevated temperatures and can completely hinder the functioning of nanowire-based devices like e.g. transparent conductive and flexible coatings. At the same time, arranged gold nanodots have important applications in electrochemical sensors. In this paper we perform a series of annealing experiments of gold and silver nanowires and nanowire junctions at fixed temperatures 473, 673, 873 and 973 K (200 °C, 400 °C, 600 °C and 700 °C) during a time period of 10 min. We show that nanowires are especially prone to fragmentation around junctions and crossing points even at comparatively low temperatures. The fragmentation process is highly temperature dependent and the junction region breaks up at a lower temperature than a single nanowire. We develop a gold parametrization for kinetic Monte Carlo simulations and demonstrate the surface diffusion origin of the nanowire junction fragmentation. We show that nanowire fragmentation starts at the junctions with high reliability and propose that aligning nanowires in a regular grid could be used as a technique for fabricating arrays of nanodots.

  15. Charge splitters and charge transport junctions based on guanine quadruplexes

    Science.gov (United States)

    Sha, Ruojie; Xiang, Limin; Liu, Chaoren; Balaeff, Alexander; Zhang, Yuqi; Zhang, Peng; Li, Yueqi; Beratan, David N.; Tao, Nongjian; Seeman, Nadrian C.

    2018-04-01

    Self-assembling circuit elements, such as current splitters or combiners at the molecular scale, require the design of building blocks with three or more terminals. A promising material for such building blocks is DNA, wherein multiple strands can self-assemble into multi-ended junctions, and nucleobase stacks can transport charge over long distances. However, nucleobase stacking is often disrupted at junction points, hindering electric charge transport between the two terminals of the junction. Here, we show that a guanine-quadruplex (G4) motif can be used as a connector element for a multi-ended DNA junction. By attaching specific terminal groups to the motif, we demonstrate that charges can enter the structure from one terminal at one end of a three-way G4 motif, and can exit from one of two terminals at the other end with minimal carrier transport attenuation. Moreover, we study four-way G4 junction structures by performing theoretical calculations to assist in the design and optimization of these connectors.

  16. Variability study of Si nanowire FETs with different junction gradients

    Directory of Open Access Journals (Sweden)

    Jun-Sik Yoon

    2016-01-01

    Full Text Available Random dopant fluctuation effects of gate-all-around Si nanowire field-effect transistors (FETs are investigated in terms of different diameters and junction gradients. The nanowire FETs with smaller diameters or shorter junction gradients increase relative variations of the drain currents and the mismatch of the drain currents between source-drain and drain-source bias change in the saturation regime. Smaller diameters decreased current drivability critically compared to standard deviations of the drain currents, thus inducing greater relative variations of the drain currents. Shorter junction gradients form high potential barriers in the source-side lightly-doped extension regions at on-state, which determines the magnitude of the drain currents and fluctuates the drain currents greatly under thermionic-emission mechanism. On the other hand, longer junction gradients affect lateral field to fluctuate the drain currents greatly. These physical phenomena coincide with correlations of the variations between drain currents and electrical parameters such as threshold voltages and parasitic resistances. The nanowire FETs with relatively-larger diameters and longer junction gradients without degrading short channel characteristics are suggested to minimize the relative variations and the mismatch of the drain currents.

  17. Q factor and resonance amplitude of Josephson tunnel junctions

    International Nuclear Information System (INIS)

    Broom, R.F.; Wolf, P.

    1977-01-01

    The surface impedance of the superconducting films comprising the electrodes of Josephson tunnel junctions has been derived from the BCS theory in the extreme London limit. Expressions have been obtained for (i) the dependence of the penetration depth lambda on frequency and temperature, and (ii) the quality factor Q of the junction cavity, attributable to surface absorption in the electrodes. The effect of thin electrodes (t 9 or approx. = lambda) is also included in the calculations. Comparison of the calculated frequency dependence of lambda with resonance measurements on Pb-alloy and all-Nb tunnel junctions yields quite good agreement, indicating that the assumptions made in the theory are reasonable. Measurements of the (current) amplitude of the resonance peaks of the junctions have been compared with the values obtained from inclusion of the calculated Q in the theory by Kulik. In common with observations on microwave cavities by other workers, we find that a small residual conductivity must be added to the real part of the BCS value. With its inclusion, good agreement is found between calculation and experiment, within the range determined by the simplifying assumptions of Kulik's theory. From the results, we believe the calculation of Q to be reasonably accurate for the materials investigated. It is shown that the resonance amplitude of Josephson junctions can be calculated directly from the material constants and a knowledge of the residual conductivity

  18. Symmetry breaking in SNS junctions: edge transport and field asymmetries

    Science.gov (United States)

    Suominen, Henri; Nichele, Fabrizio; Kjaergaard, Morten; Rasmussen, Asbjorn; Danon, Jeroen; Flensberg, Karsten; Levitov, Leonid; Shabani, Javad; Palmstrom, Chris; Marcus, Charles

    We study magnetic diffraction patterns in a tunable superconductor-semiconductor-superconductor junction. By utilizing epitaxial growth of aluminum on InAs/InGaAs we obtain transparent junctions which display a conventional Fraunhofer pattern of the critical current as a function of applied perpendicular magnetic field, B⊥. By studying the angular dependence of the critical current with applied magnetic fields in the plane of the junction we find a striking anisotropy. We attribute this effect to dephasing of Andreev states in the bulk of the junction, leading to SQUID like behavior when the magnetic field is applied parallel to current flow. Furthermore, in the presence of both in-plane and perpendicular fields, asymmetries in +/-B⊥ are observed. We suggest possible origins and discuss the role of spin-orbit and Zeeman physics together with a background disorder potential breaking spatial symmetries of the junction. Research supported by Microsoft Project Q, the Danish National Research Foundation and the NSF through the National Nanotechnology Infrastructure Network.

  19. Testicular cell junction: a novel target for male contraception.

    Science.gov (United States)

    Lee, Nikki P Y; Wong, Elissa W P; Mruk, Dolores D; Cheng, C Yan

    2009-01-01

    Even though various contraceptive methods are widely available, the number of unwanted pregnancies is still on the rise in developing countries, pressurizing the already resource limited nations. One of the major underlying reasons is the lack of effective, low cost, and safe contraceptives for couples. During the past decade, some studies were performed using animal models to decipher if the Sertoli-germ cell junction in the testis is a target for male fertility regulation. Some of these study models were based on the use of hormones and/or chemicals to disrupt the hypothalamic-pituitary-testicular axis (e.g., androgen-based implants or pills) and others utilized a panel of chemical entities or synthetic peptides to perturb spermatogenesis either reversibly or non-reversibly. Among them, adjudin, a potential male contraceptive, is one of the compounds exerting its action on the unique adherens junctions, known as ectoplasmic specializations, in the testis. Since the testis is equipped with inter-connected cell junctions, an initial targeting of one junction type may affect the others and these accumulative effects could lead to spermatogenic arrest. This review attempts to cover an innovative theme on how male infertility can be achieved by inducing junction instability and defects in the testis, opening a new window of research for male contraceptive development. While it will still take much time and effort of intensive investigation before a product can reach the consumable market, these findings have provided hope for better family planning involving men.

  20. Regulation of Endothelial Adherens Junctions by Tyrosine Phosphorylation

    Science.gov (United States)

    Adam, Alejandro Pablo

    2015-01-01

    Endothelial cells form a semipermeable, regulated barrier that limits the passage of fluid, small molecules, and leukocytes between the bloodstream and the surrounding tissues. The adherens junction, a major mechanism of intercellular adhesion, is comprised of transmembrane cadherins forming homotypic interactions between adjacent cells and associated cytoplasmic catenins linking the cadherins to the cytoskeleton. Inflammatory conditions promote the disassembly of the adherens junction and a loss of intercellular adhesion, creating openings or gaps in the endothelium through which small molecules diffuse and leukocytes transmigrate. Tyrosine kinase signaling has emerged as a central regulator of the inflammatory response, partly through direct phosphorylation and dephosphorylation of the adherens junction components. This review discusses the findings that support and those that argue against a direct effect of cadherin and catenin phosphorylation in the disassembly of the adherens junction. Recent findings indicate a complex interaction between kinases, phosphatases, and the adherens junction components that allow a fine regulation of the endothelial permeability to small molecules, leukocyte migration, and barrier resealing. PMID:26556953

  1. Human zonulin, a potential modulator of intestinal tight junctions.

    Science.gov (United States)

    Wang, W; Uzzau, S; Goldblum, S E; Fasano, A

    2000-12-01

    Intercellular tight junctions are dynamic structures involved in vectorial transport of water and electrolytes across the intestinal epithelium. Zonula occludens toxin derived from Vibrio cholerae interacts with a specific intestinal epithelial surface receptor, with subsequent activation of a complex intracellular cascade of events that regulate tight junction permeability. We postulated that this toxin may mimic the effect of a functionally and immunologically related endogenous modulator of intestinal tight junctions. Affinity-purified anti-zonula occludens toxin antibodies and the Ussing chamber assay were used to screen for one or more mammalian zonula occludens toxin analogues in both fetal and adult human intestine. A novel protein, zonulin, was identified that induces tight junction disassembly in non-human primate intestinal epithelia mounted in Ussing chambers. Comparison of amino acids in the active zonula occludens toxin fragment and zonulin permitted the identification of the putative receptor binding domain within the N-terminal region of the two proteins. Zonulin likely plays a pivotal role in tight junction regulation during developmental, physiological, and pathological processes, including tissue morphogenesis, movement of fluid, macromolecules and leukocytes between the intestinal lumen and the interstitium, and inflammatory/autoimmune disorders.

  2. Gap junctions are selectively associated with interlocking ball-and-sockets but not protrusions in the lens.

    Science.gov (United States)

    Biswas, Sondip K; Lee, Jai Eun; Brako, Lawrence; Jiang, Jean X; Lo, Woo-Kuen

    2010-11-09

    -rich versus cholesterol-free) as seen with the filipin-cholesterol-complexes (FCC) in different cortical regions during maturation. In contrast, the protrusions contained consistently high cholesterol amounts (i.e., 402 FCCs/μm2 membrane) which were approximately two times greater than that of the cholesterol-rich gap junctions (i.e., 188 FCCs/μm2 membrane) found in ball-and-sockets. Gap junctions are regularly associated with all ball-and-sockets examined in metabolically active young cortical fibers, but not with protrusions, in both chicken and monkey lenses. Since these unique gap junctions often protrude deeply into neighboring cells to increase membrane surface areas, they may significantly facilitate cell-to-cell communication between young cortical fiber cells. In particular, the large number of ball-and-socket gap junctions found near the equatorial region may effectively facilitate the flow of outward current toward the equatorial surface for internal circulation of ions in the lens. In contrast, a consistent distribution of high concentrations of cholesterol in protrusions would make the protrusion membrane less deformable and would be more suitable for maintaining fiber-to-fiber stability during visual accommodation. Thus, the ball-and-sockets and protrusions are two structurally and functionally distinct membrane domains in the lens.

  3. Geochemical investigation of UMTRAP designated site at Grand Junction, Colorado

    International Nuclear Information System (INIS)

    Markos, G.; Bush, K.J.

    1983-09-01

    This report is the result of a geochemical investigation of the former uranium mill and tailings site at Grand Junction, Colorado. The objectives of the investigation are to characterize the geochemistry, to determine the contaminant distribution resulting from the former milling activities and tailings, and to infer chemical pathways and transport mechanisms from the contaminant distribution. The results should be used to model contaminant migration and to develop criteria for long-term containment media, such as a cover system which is impermeable to contaminant migration. This report assumes a familiarity with the hydrologic conditions of the site and the geochemical concepts underlying the investigation. The results reported are based on a sampling of waters in two seasons and solid material from the background, the area adjacent to the site, and the site. The solid samples were water extracted to remove easily soluble salts and acid extracted to remove carbonates and hydroxides. The water extracts and solid samples were analyzed for the major and trace elements. A limited number of samples were analyzed for radiological components. The report includes the methods of sampling, sample processing, analysis, and data interpretation. Four major conclusions are: (1) trace element concentrations in shallow subsurface waters adjacent to the tailings temporally vary up to an order of magnitude; (2) the riverbank soils and borehole waters are contaminated with uranium, radium, and trace elements from discharge of tailings solids and solutions during the active time of the mill; however, the movement of contaminants toward the Colorado River does not appear to be significant; (3) the Colorado River adjacent to the tailings is not contaminated; and (4) trace metals have accumulated at both the tailings/cover and tailings/soil interface because of precipitation reactions caused by chemical differences between the two materials

  4. Traumatic Tear of the Latissimus Dorsi Myotendinous Junction

    Science.gov (United States)

    Friedman, Michael V.; Stensby, J. Derek; Hillen, Travis J.; Demertzis, Jennifer L.; Keener, Jay D.

    2015-01-01

    A case of a latissimus dorsi myotendinous junction strain in an avid CrossFit athlete is presented. The patient developed acute onset right axillary burning and swelling and subsequent palpable pop with weakness while performing a “muscle up.” Magnetic resonance imaging examination demonstrated a high-grade tear of the right latissimus dorsi myotendinous junction approximately 9 cm proximal to its intact humeral insertion. There were no other injuries to the adjacent shoulder girdle structures. Isolated strain of the latissimus dorsi myotendinous junction is a very rare injury with a scarcity of information available regarding its imaging appearance and preferred treatment. This patient was treated conservatively and was able to resume active CrossFit training within 3 months. At 6 months postinjury, he had only a mild residual functional deficit compared with his preinjury level. PMID:26502450

  5. Pure spin polarized current through a full magnetic silicene junction

    Science.gov (United States)

    Lorestaniweiss, Zeinab; Rashidian, Zeinab

    2018-06-01

    Using the Landauer-Buttiker formula, we investigate electronic transport in silicene junction composed of ferromagnetic silicene. The direction of magnetization in the middle region may change in a plane perpendicular to the junction, whereas the magnetization direction keep fixed upward in silicene electrodes. We investigate how the various magnetization directions in the middle region affect the electronic transport. We demonstrate that conductance depends on the orientation of magnetizations in the middle region. It is found that by changing the direction of the magnetization in the middle region, a pure spin up current can be achieved. This achievement makes this full magnetic junction a good design for a full spin-up current polarizer.

  6. Measurement of noise in YBCO bi-crystal junctions

    International Nuclear Information System (INIS)

    Kuznik, J.; Hao, L.; Macfarlane, J.C.; Pegrum, C.M.; Fischer, G.M.; Mygind, J.; Pedersen, N.F.; Beck, A.; Gross, R.

    1993-01-01

    This paper describes collaborative work between three institutions as part of an ESPRIT programme to fabricate and characterise grain-boundary junctions. Bi-crystal junctions were fabricated at Tuebingen on SrTiO 3 substrates with a 24 misorientation angle and a-b tilt. 200nm of c-axis YBCO was sputter-deposited using a hollow-cathode magnetron, and the films patterned with optical lithography and Ar ion beam etching (3). For test purposes junctions with a range of sizes were made, with widths between 4 and 20μm. These have been characterised for noise properties at 0.3 - 1kHz and 60kHz at Strathclyde, and at 70GHz at Lyngby. (orig.)

  7. Filtering microfluidic bubble trains at a symmetric junction.

    Science.gov (United States)

    Parthiban, Pravien; Khan, Saif A

    2012-02-07

    We report how a nominally symmetric microfluidic junction can be used to sort all bubbles of an incoming train exclusively into one of its arms. The existence of this "filter" regime is unexpected, given that the junction is symmetric. We analyze this behavior by quantifying how bubbles modulate the hydrodynamic resistance in microchannels and show how speeding up a bubble train whilst preserving its spatial periodicity can lead to filtering at a nominally symmetric junction. We further show how such an asymmetric traffic of bubble trains can be triggered in symmetric geometries by identifying conditions wherein the resistance to flow decreases with an increase in the number of bubbles in the microchannel and derive an exact criterion to predict the same.

  8. Resistance switch employing a simple metal nanogap junction

    International Nuclear Information System (INIS)

    Naitoh, Yasuhisa; Horikawa, Masayo; Abe, Hidekazu; Shimizu, Tetsuo

    2006-01-01

    In recent years, several researchers have reported the occurrence of reversible resistance switching effects in simple metal nanogap junctions. A large negative resistance is observed in the I-V characteristics of such a junction when high-bias voltages are applied. This phenomenon is characteristic behaviour on the nanometre scale; it only occurs for gap widths slightly under 13 nm. Furthermore, such a junction exhibits a non-volatile resistance hysteresis when the bias voltage is reduced very rapidly from a high level to around 0 V, and when the bias voltage is reduced slowly. This non-volatile resistance change occurs as a result of changes in the gap width between the metal electrodes, brought about by the applied bias voltage

  9. LTS junction technology for RSFQ and qubit circuit applications

    International Nuclear Information System (INIS)

    Buchholz, F.-Im.; Balashov, D.V.; Dolata, R.; Hagedorn, D.; Khabipov, M.I.; Kohlmann, J.; Zorin, A.B.; Niemeyer, J.

    2006-01-01

    The potentials of LTS junction technology and electronics offer innovative solutions for the processing of quantum information in RSFQ and qubit circuits. We discuss forthcoming approaches based on standard SIS technology and addressed to the development of new superconducting device concepts. The challenging problem of reducing back action noise of the RSFQ circuits deteriorating coherent properties of the qubit is currently solved by implementing Josephson junctions with non-linear shunts based on LTS SIS-SIN technology. Upgraded NbAlO x trilayer technology enables the fabrication of high-quality mesoscopic Josephson junction transistors down to the nanometer range suitable for a qubit-operation regime. As applications, circuit concepts are presented which combine superconducting devices of different nature

  10. Reactive tunnel junctions in electrically driven plasmonic nanorod metamaterials

    Science.gov (United States)

    Wang, Pan; Krasavin, Alexey V.; Nasir, Mazhar E.; Dickson, Wayne; Zayats, Anatoly V.

    2018-02-01

    Non-equilibrium hot carriers formed near the interfaces of semiconductors or metals play a crucial role in chemical catalysis and optoelectronic processes. In addition to optical illumination, an efficient way to generate hot carriers is by excitation with tunnelling electrons. Here, we show that the generation of hot electrons makes the nanoscale tunnel junctions highly reactive and facilitates strongly confined chemical reactions that can, in turn, modulate the tunnelling processes. We designed a device containing an array of electrically driven plasmonic nanorods with up to 1011 tunnel junctions per square centimetre, which demonstrates hot-electron activation of oxidation and reduction reactions in the junctions, induced by the presence of O2 and H2 molecules, respectively. The kinetics of the reactions can be monitored in situ following the radiative decay of tunnelling-induced surface plasmons. This electrically driven plasmonic nanorod metamaterial platform can be useful for the development of nanoscale chemical and optoelectronic devices based on electron tunnelling.

  11. Fluxons in long and annular intrinsic Josephson junction stacks

    CERN Document Server

    Clauss, T; Moessle, M; Müller, A; Weber, A; Kölle, D; Kleiner, R

    2002-01-01

    A promising approach towards a THz oscillator based on intrinsic Josephson junctions in high-temperature superconductors is based on the collective motion of Josephson fluxons, which are predicted to form various configurations ranging from a triangular to a quadratic lattice. Not only for this reason, but certainly also for the sake of basic physics, several experimental and theoretical investigations have been done on the subject of collective fluxon dynamics in stacked intrinsic Josephson junctions. In this paper we will present some experimental results on the fluxon dynamics of long intrinsic Josephson junction stacks made of Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8. The stacks were formed either in an open or in an annular geometry, and clear resonant fluxon modes were observed. Experiments discussed include measurements of current-voltage characteristics in external magnetic fields and in external microwave fields.

  12. Trichomonas vaginalis perturbs the junctional complex in epithelial cells

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Trichomonas vaginalis, a protist parasite of the urogenital tract in humans, is the causative agent of trichomonosis,which in recent years have been associated with the cervical cancer development. In the present study we analyzed the modifications at the junctional complex level of Caco-2 cells after interaction with two isolates of T. vaginalis and the influence of the iron concentration present in the parasite's culture medium on the interaction effects. Our results show that T. vaginalis adheres to the epithelial cell causing alterations in the junctional complex, such as: (a) a decrease in transepithelial electrical resistance; (b) alteration in the pattern of junctional complex proteins distribution as obseryed for E-cadherin, occludin and ZO-1; and (c) enlargement of the spaces between epithelial cells. These effects were dependent on (a) the degree of the parasite virulence isolate, (b) the iron concentration in the culture medium, and (c) the expression of adhesin proteins on the parasite surface.

  13. Coherence in a transmon qubit with epitaxial tunnel junctions

    Energy Technology Data Exchange (ETDEWEB)

    Weides, Martin [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Karlsruhe Institute of Technology (Germany); Kline, Jeffrey; Vissers, Michael; Sandberg, Martin; Pappas, David [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Wisbey, David [National Institute of Standards and Technology, Boulder, Colorado 80305 (United States); Saint Louis University, St. Louis, Missouri 63103 (United States); Johnson, Blake; Ohki, Thomas [Raytheon BBN Technologies, Cambridge, Massachusetts 02138 (United States)

    2012-07-01

    Transmon qubits based on epitaxial tunnel junctions and interdigitated capacitors were developed. This multileveled qubit, patterned by use of all-optical lithography, is a step towards scalable qubits with a high integration density. The relaxation time T{sub 1} is.72-.86 {mu} sec and the ensemble dephasing time T{sub 2}{sup *} is slightly larger than T{sub 1}. The dephasing time T{sub 2} (1.36 {mu} sec) is nearly energy-relaxation-limited. Qubit spectroscopy yields weaker level splitting than observed in qubits with amorphous barriers in equivalent-size junctions. The qubit's inferred microwave loss closely matches the weighted losses of the individual elements (junction, wiring dielectric, and interdigitated capacitor), determined by independent resonator measurements.

  14. NbCN Josephson junctions with AlN barriers

    International Nuclear Information System (INIS)

    Thomasson, S.L.; Murduck, J.M.; Chan, H.

    1991-01-01

    This paper reports on niobium carbonitride (NbCN) Josephson circuits which operate over a wider temperature range than either niobium or niobium nitride circuits. Higher operating temperature places NbCN technology more comfortably within the range of closed cycle refrigerators, a key factor in aerospace applications. We have fabricated tunnel junctions from NbCN films with transition temperatures up to 18 Kelvin. High quality NbCN tunnel junction fabrication generally requires low stress films with roughness less than the barrier thickness (∼20 Angstrom). We have developed scanning tunneling microscopy as a tool for measuring and optimizing film smoothness. Junctions formed in situ with AIN tunneling barriers show reproducible I-V characteristics

  15. Tuning spin transport across two-dimensional organometallic junctions

    Science.gov (United States)

    Liu, Shuanglong; Wang, Yun-Peng; Li, Xiangguo; Fry, James N.; Cheng, Hai-Ping

    2018-01-01

    We study via first-principles modeling and simulation two-dimensional spintronic junctions made of metal-organic frameworks consisting of two Mn-phthalocyanine ferromagnetic metal leads and semiconducting Ni-phthalocyanine channels of various lengths. These systems exhibit a large tunneling magnetoresistance ratio; the transmission functions of such junctions can be tuned using gate voltage by three orders of magnitude. We find that the origin of this drastic change lies in the orbital alignment and hybridization between the leads and the center electronic states. With physical insight into the observed on-off phenomenon, we predict a gate-controlled spin current switch based on two-dimensional crystallines and offer general guidelines for designing spin junctions using 2D materials.

  16. High quality factor HTS Josephson junctions on low loss substrates

    Energy Technology Data Exchange (ETDEWEB)

    Stornaiuolo, D; Longobardi, L; Massarotti, D; Barone, A; Tafuri, F [CNR-SPIN Napoli, Complesso Universitario di Monte Sant' Angelo, via Cinthia, 80126 Napoli (Italy); Papari, G; Carillo, F [NEST, CNR-NANO and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa (Italy); Cennamo, N [Dipartimento Ingegneria dell' Informazione, Seconda Universita degli Studi di Napoli, via Roma 29, 81031 Aversa (Italy)

    2011-04-15

    We have extended the off-axis biepitaxial technique to produce YBCO grain boundary junctions on low loss substrates. Excellent transport properties have been reproducibly found, with remarkable values of the quality factor I{sub c}R{sub n} (with I{sub c} the critical current and R{sub n} the normal state resistance) above 10 mV, far higher than the values commonly reported in the literature for high temperature superconductor (HTS) based Josephson junctions. The outcomes are consistent with a picture of a more uniform grain boundary region along the current path. This work supports a possible implementation of grain boundary junctions for various applications including terahertz sensors and HTS quantum circuits in the presence of microwaves.

  17. T-junctions and perceived slant of partially occluded surfaces.

    Science.gov (United States)

    Grove, Philip M; Ono, Hiroshi; Kaneko, Hirohiko

    2003-01-01

    Häkkinen and Nyman (1997 Perception 26 29-38) reported that perceived slant is reduced when occlusion is a possible interpretation for the visual system. We present data from three experiments that confirm and expand on their finding. Our stimuli consisted of four types of stereograms depicting white central rectangles flanked on either side by two grey rectangles. The central white rectangles varied in height, thus manipulating the polarity of the T-junction information between the central and flanking rectangles. Perceived slant was smallest or not apparent when T-junction information indicated the central rectangles were nearer than the flanking rectangles and greatest when T-junction information indicated a farther central rectangle. Slant estimates for a stimulus containing a subjective pacmen-induced central rectangle were biased towards a depth step when an occlusion interpretation was possible.

  18. Breaking gold nano-junctions simulation and analysis

    DEFF Research Database (Denmark)

    Lauritzen, Kasper Primdal

    , to predict the structure of a gold junction just as it breaks. This method is based on artificial neural networks and can be used on experimental data, even when it is trained purely on simulated data. The method is extended to other types of experimental traces, where it is trained without the use......Simulating the movements of individual atoms allows us to look at and investigate the physical processes that happen in an experiment. In this thesis I use simulations to support and improve experimental studies of breaking gold nano-junctions. By using molecular dynamics to study gold nanowires, I...... can investigate their breaking forces under varying conditions, like stretching rate or temperature. This resolves a confusion in the literature, where the breaking forces of two different breaking structures happen to coincide. The correlations between the rupture and reformation of a gold junction...

  19. Microwave oscillator using arrays of long Josephson junctions

    International Nuclear Information System (INIS)

    Pagano, S.; Monaco, R.; Costabile, G.

    1989-01-01

    The authors report on measurements performed on integrated superconducting devices based on arrays of long Josephson tunnel junctions operating in the resonant fluxon oscillation regime (i.e. biased on the Zero Field Steps). The electromagnetic coupling among the junction causes a mutual phase-locking of the fluxon oscillations with a corresponding increase of the emitted power and a decrease of the signal linewidth. This phase-locked state can be controlled by means of an external dc bias current and magnetic field. The effect of the generated microwave signal has been observed on a small Josephson tunnel junction coupled to the array via a microstrip transmission line. The feasibility of the reported devices as local oscillators in an integrated microwave Josephson receiver is discussed

  20. A charge-based model of Junction Barrier Schottky rectifiers

    Science.gov (United States)

    Latorre-Rey, Alvaro D.; Mudholkar, Mihir; Quddus, Mohammed T.; Salih, Ali

    2018-06-01

    A new charge-based model of the electric field distribution for Junction Barrier Schottky (JBS) diodes is presented, based on the description of the charge-sharing effect between the vertical Schottky junction and the lateral pn-junctions that constitute the active cell of the device. In our model, the inherently 2-D problem is transformed into a simple but accurate 1-D problem which has a closed analytical solution that captures the reshaping and reduction of the electric field profile responsible for the improved electrical performance of these devices, while preserving physically meaningful expressions that depend on relevant device parameters. The validation of the model is performed by comparing calculated electric field profiles with drift-diffusion simulations of a JBS device showing good agreement. Even though other fully 2-D models already available provide higher accuracy, they lack physical insight making the proposed model an useful tool for device design.