WorldWideScience

Sample records for high fill-factor triangular

  1. Liquid crystal spherical microlens array with high fill factor and optical power.

    Science.gov (United States)

    Algorri, José Francisco; Urruchi, Virginia; Bennis, Noureddine; Morawiak, Przemek; Sánchez-Pena, José Manuel; Otón, José Manuel

    2017-01-23

    A novel liquid crystal spherical microlens array with high optical power and almost 100% of fill-factor is proposed and experimentally demonstrated. The combination of a specific structure and electrical waveforms applied to the electrodes generates an array of spherical microlenses with square aperture. The manufacturing process is simple (patterned electrodes) and the microlenses are reconfigurable by low voltage signals (the electrodes are in contact with the LC layer). This device could be a key for the next generation of autostereoscopic devices based on Integral Imaging technique.

  2. High Fill-Factor Imagers for Neuromorphic Processing Enabled by Floating-Gate Circuits

    Directory of Open Access Journals (Sweden)

    Hasler Paul

    2003-01-01

    Full Text Available In neuromorphic modeling of the retina, it would be very nice to have processing capabilities at the focal plane while retaining the density of typical active pixel sensor (APS imager designs. Unfortunately, these two goals have been mostly incompatible. We introduce our transform imager technology and basic architecture that uses analog floating-gate devices to make it possible to have computational imagers with high pixel densities. This imager approach allows programmable focal-plane processing that can perform retinal and higher-level bioinspired computation. The processing is performed continuously on the image via programmable matrix operations that can operate on the entire image or blocks within the image. The resulting dataflow architecture can directly perform computation of spatial transforms, motion computations, and stereo computations. The core imager performs computations at the pixel plane, but still holds a fill factor greater than 40 percent—comparable to the high fill factors of APS imagers. Each pixel is composed of a photodiode sensor element and a multiplier. We present experimental results from several imager arrays built in 0.5 m process (up to in an area of 4 millimeter squared.

  3. High Fill Factor 512 X 512 PtSi Focal Plane Array

    Science.gov (United States)

    Wang, Weng-Lyang; Winzenread, Rusty; Nguyen, Buon T.; Murrin, James J.; Trubiano, Robert L.

    1989-12-01

    A 512 x 512 monolithic PtSi Schottky Barrier Diode (SBD) array that was designed, fabricated and tested at EG&G Reticon will be discussed. The array uses a novel line-addressed charge-accumulation (LACA) CCD in an interline configuration for the vertical registers and a multiple-readout register for high speed readout. The LACA readout structure has two distinct advantages over the conventional interline CCD structure. First, the LACA register occupies a very small area while still providing enough charge handling capacity ¬Â¢ for the Schottky barrier detector. As a result, the 30 gm x 30 gm pixels have a fill factor of 54% when designed with a 2.5 Lim minimum dimension CCD process. Secondly, since the register operates in a charge accumulation mode, it has an extremely high effective charge accumulation efficiency. In the horizontal register, four readout structures are used to increase the overall pixel readout rate. A 75 Hz frame rate is achieved when the horizontal clock rate is 5 MHz. A CCD bending structure is utilized at each output to eliminate any coupling from the common clock lines. Each output has an electron sensitivity of greater than 5 0/e. The quantum yield of the platinum silicide SBDs has been between 15 and 25%. The chip dimensions are 748 mil x 748 mil, of which 604 mil x 604 mil is photosensitive.

  4. Enhanced sensitivity to near-infrared with high fill factor in small molecular organic solar cells

    Science.gov (United States)

    Shim, Hyun-Sub; Kim, Hyo Jung; Kim, Ji Whan; Kim, Sei-Yong; Jeong, Won-Ik; Kim, Tae-Min; Kim, Jang-Joo

    2012-09-01

    High efficiency near-infrared (NIR) absorbing solar cells based on lead phthalocyanine (PbPc) are reported using copper iodide (CuI) as a templating layer to control the crystal structure of PbPc. Devices with CuI inserted between the ITO and PbPc layers exhibit a two times enhancement of the JSC compared to the case in the absence of the CuI layer. This is due to the increase of crystallinity in the molecules grown on the CuI templating layer, which is investigated via an x-ray diffraction study. Moreover, fill factor is also enhanced to 0.63 from 0.57 due to low series resistance although the additional CuI layer is inserted between the ITO and the PbPc layer. As a result, the corrected power conversion efficiency of 2.5% was obtained, which is the highest one reported up to now among the PbPc based solar cells.

  5. Analyses of mode filling factor of a laser end-pumped by a LD with high-order transverse modes

    Science.gov (United States)

    Han, Juhong; Wang, You; An, Guofei; Rong, Kepeng; Yu, Hang; Wang, Shunyan; Zhang, Wei; Cai, He; Xue, Liangping; Wang, Hongyuan; Zhou, Jie

    2017-05-01

    Although the concept of the mode filling factor (also named as "mode-matching efficiency") has been well discussed decades before, the concept of so-called overlap coefficient is often confused by the laser technicians because there are several different formulae for various engineering purposes. Furthermore, the LD-pumped configurations have become the mainstream of solid-state lasers since their compact size, high optical-to-optical efficiency, low heat generation, etc. As the beam quality of LDs are usually very unsatisfactory, it is necessary to investigate how the mode filling factor of a laser system is affected by a high-powered LD pump source. In this paper, theoretical analyses of an end-pumped laser are carried out based on the normalized overlap coefficient formalism. The study provides a convenient tool to describe the intrinsically complex issue of mode interaction corresponding to a laser and an end-pumped source. The mode filling factor has been studied for many cases in which the pump mode and the laser mode have been considered together in the calculation based on analyses of the rate equations. The results should be applied for analyses of any other types of lasers with the similar optical geometry.

  6. Efficient small molecule bulk heterojunction solar cells with high fill factors via pyrene-directed molecular self-assembly

    KAUST Repository

    Lee, Olivia P.

    2011-10-21

    Efficient organic photovoltaic (OPV) materials are constructed by attaching completely planar, symmetric end-groups to donor-acceptor electroactive small molecules. Appending C2-pyrene as the small molecule end-group to a diketopyrrolopyrrole core leads to materials with a tight, aligned crystal packing and favorable morphology dictated by π-π interactions, resulting in high power conversion efficiencies and high fill factors. The use of end-groups to direct molecular self-assembly is an effective strategy for designing high-performance small molecule OPV devices. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Highly Efficient Porphyrin-Based OPV/Perovskite Hybrid Solar Cells with Extended Photoresponse and High Fill Factor.

    Science.gov (United States)

    Gao, Ke; Zhu, Zonglong; Xu, Bo; Jo, Sae Byeok; Kan, Yuanyuan; Peng, Xiaobin; Jen, Alex K-Y

    2017-12-01

    Employing a layer of bulk-heterojunction (BHJ) organic semiconductors on top of perovskite to further extend its photoresponse is considered as a simple and promising way to enhance the efficiency of perovskite-based solar cells, instead of using tandem devices or near infrared (NIR)-absorbing Sn-containing perovskites. However, the progress made from this approach is quite limited because very few such hybrid solar cells can simultaneously show high short-circuit current (J SC ) and fill factor (FF). To find an appropriate NIR-absorbing BHJ is essential for highly efficient, organic, photovoltaics (OPV)/perovskite hybrid solar cells. The materials involved in the BHJ layer not only need to have broad photoresponse to increase J SC , but also possess suitable energy levels and high mobility to afford high V OC and FF. In this work, a new porphyrin is synthesized and blended with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) to function as an efficient BHJ for OPV/perovskite hybrid solar cells. The extended photoresponse, well-matched energy levels, and high hole mobility from optimized BHJ morphology afford a very high power conversion efficiency (PCE) (19.02%) with high V oc , J SC , and FF achieved simultaneously. This is the highest value reported so far for such hybrid devices, which demonstrates the feasibility of further improving the efficiency of perovskite devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Environmentally Printing Efficient Organic Tandem Solar Cells with High Fill Factors: A Guideline Towards 20% Power Conversion Efficiency

    DEFF Research Database (Denmark)

    Li, Ning; Baran, Derya; Spyropoulos, George D.

    2014-01-01

    The tandem concept involves stacking two or more cells with complementary absorption spectra in series or parallel connection, harvesting photons at the highest possible potential. It is strongly suggested that the roll-to-roll production of organic solar cells will employ the tandem concept...... to enhance the power conversion efficiency (PCE). However, due to the undeveloped deposition techniques, the challenges in ink formulation as well as the lack of commercially available high performance active materials, roll-to-roll fabrication of highly efficient organic tandem solar cells currently...... presents a major challenge. The reported high PCE values from lab-scale spin-coated devices are, of course, representative, but not helpful for commercialization. Here, organic tandem solar cells with exceptionally high fill factors and PCE values of 7.66% (on glass) and 5.56% (on flexible substrate...

  9. Inductively coupled plasma etching and processing techniques for type-II InAs/GaSb superlattices infrared detectors toward high fill factor focal plane arrays

    Science.gov (United States)

    Huang, E. K.; Nguyen, B.-M.; Hoffman, D.; Delaunay, P.-Y.; Razeghi, M.

    2009-01-01

    A challenge for type-II InAs/GaSb superlattice (T2SL) photodetectors is to achieve high fill factor, high aspect ratio etching for third generation focal plane arrays (FPAs). Initially, we compare the morphological and electrical results of single element T2SL photodiodes after BCl3/Ar inductively coupled plasma (ICP) and electron cyclotron resonance (ECR) dry etching. Using a Si3N4 hard mask, ICP-etched structures exemplify greater sidewall verticality and smoothness, which are essential toward the realization of high fill factor FPAs. ICP-etched single element devices with SiO2 passivation that are 9.3μm in cutoff wavelength achieved vertical sidewalls of 7.7μm in depth with a resistance area product at zero bias of greater than 1,000 Ωcm2 and maximum differential resistance in excess of 10,000 Ωcm2 at 77K. By only modifying the etching technique in the fabrication steps, the ICP-etched photodiodes showed an order of magnitude decrease in their dark current densities in comparison to the ECR-etched devices. Finally, high aspect ratio etching is demonstrated on mutli-element arrays with 3μm-wide trenches that are 11μm deep.

  10. High magnetic field magnetization of a new triangular lattice antiferromagnet

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, H. D. [Univ. of Tennessee, Knoxville, TN (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States). National High Magnetic Field Lab. (MagLab); Stritzinger, Laurel Elaine Winter [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Harrison, Neil [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-23

    In CsV(MoO4)2, the magnetic V3+ ions with octahedral oxygen-coordination form a geometrically frustrated triangular lattice. So fare, there is no magnetic properties reported on it. Recently, we successfully grew single crystals of CsV(MoO4)2 by using flux method. The susceptibility shows a sharp drop around 24 K, representing a long range magnetic ordering. To understand the physical properties of this new triangular lattice antiferromagnet (TLAF), we pursued high field magnetization measurements to answer two questions: (i) what is the saturation field, which will be very useful to calculate the exchange interaction of the system? (ii) Will it exhibit spin state transition, such as the up up down phase with 1/3-saturation moment as other TLAFs? Recently, we performed VSM measurements in Cell 8, Tallahassee, NHMFL, the results show that the magnetization reaches 0.38 MuB at 34 T, which is just 19% of the full moment of 2 MuB for V3+ (3d2) ions. Apparently we need higher field to reach 1/3 value or full moment.

  11. Flexible organic tandem solar modules with 6% efficiency: combining roll-to-roll compatible processing with high geometric fill factors

    DEFF Research Database (Denmark)

    Spyropoulos, G. D.; Kubis, P.; Li, Na

    2014-01-01

    Organic solar cell technology bears the potential for high photovoltaic performance combined with truly low-cost, high-volume processing. Here we demonstrate organic tandem solar modules on flexible substrates fabricated by fully roll-to-roll compatible processing at temperatures...

  12. Strontium insertion in methlyammonium lead iodide: long charge carrier lifetime and high fill factor solar cells (Conference Presentation)

    Science.gov (United States)

    Momblona, Cristina; Gil-Escrig, Lidón; Ávila, Jorge; Pérez-Del-Rey, Daniel; Forgács, David; Sessolo, Michele; Bolink, Hendrik J.

    2016-09-01

    Organic-inorganic (hybrid) lead halide perovskites are taking the lead among the emerging photovoltaics technologies, thanks to the demonstration of power conversion efficiencies exceeding 20 %. Hybrid perovskites have a wide spectrum of desirable properties; they are direct bandgap semiconductors with very high absorption coefficients, high and balanced hole and electron mobility, and large diffusion length. A unique feature of these materials is their versatility in terms of bandgap energy, which can be tuned by simple exchange of their components. In this paper we present vacuum and hybrid deposition routes for the preparation of different organic-inorganic lead perovskite thin films, and their incorporation into efficient solar cells. The influence of the type of organic semiconductors used as hole/electron transport layer in p-i-n solar cells will be presented. We also discuss their electroluminescence properties, either for applications in light-emitting diodes or as a diagnostic tool of the optical and electronic quality of perovskite thin films. Finally, the effect of additives and dopants in the perovskite absorber as well as in the charge selective layers will be described.

  13. 3D integration of Geiger-mode avalanche photodiodes aimed to very high fill-factor pixels for future linear colliders 

    CERN Document Server

    Vilella, E; Dieguez, A

    2013-01-01

    This paper presents an analysis of the maximum achievable fill-factor by a pixel detector of Geiger-mode avalanche photodiodes with the Chartered 130 nm/Tezzaron 3D process. The analysis shows that fillfactors between 66% and 96% can be obtained with different array architectures and a time-gated readout circuit of minimum area. The maximum fill-factor is achieved when the two-layer vertical stack is used to overlap the non-sensitive areas of one layer with the sensitive areas of the other one. Moreover, different sensor areas are used to further increase the fill-factor. A chip containing a pixel detector of the Geigermode avalanche photodiodes and aimed to future linear colliders has been designed with the Chartered 130 nm/Tezzaron 3D process to increase the fill-factor.

  14. Inverted Planar Perovskite Solar Cells with a High Fill Factor and Negligible Hysteresis by the Dual Effect of NaCl-Doped PEDOT:PSS.

    Science.gov (United States)

    Hu, Lijun; Sun, Kuan; Wang, Ming; Chen, Wei; Yang, Bo; Fu, Jiehao; Xiong, Zhuang; Li, Xinyi; Tang, Xiaosheng; Zang, Zhigang; Zhang, Shupeng; Sun, Lidong; Li, Meng

    2017-12-20

    The performance of inverted perovskite solar cells is highly dependent on hole extraction and surface properties of hole transport layers. To highlight the important role of hole transport layers, a facile and simple method is developed by adding sodium chloride (NaCl) into poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The average power conversion efficiency of the perovskite solar cells prepared on NaCl-doped PEDOT:PSS is 17.1% with negligible hysteresis, compared favorably to the control devices (15.1%). Particularly, they exhibit markedly improved Voc and fill factor (FF), with the best FF as high as 81.9%. The enhancement of photovoltaic performance is ascribed to two effects. Better conductivity and hole extraction of PEDOT:PSS are observed after NaCl doping. More intriguingly, the perovskite polycrystalline film shows a preferred orientation along the (001) direction on NaCl-doped PEDOT:PSS, leading to a more uniform thin film. The comparison of the crystal structure between NaCl and MAPbCl3 indicates a lattice constant mismatch less than 2% and a matched chlorine atom arrangement on the (001) surface, which implies that the NaCl crystallites on the top surface of PEDOT:PSS might serve as seeds guiding the growth of perovskite crystals. This simple method is fully compatible with printing technologies to mass-produce perovskite solar cells with high efficiency and tunable crystal orientations.

  15. High-Performance CH3NH3PbI3-Inverted Planar Perovskite Solar Cells with Fill Factor Over 83% via Excess Organic/Inorganic Halide.

    Science.gov (United States)

    Jahandar, Muhammad; Khan, Nasir; Lee, Hang Ken; Lee, Sang Kyu; Shin, Won Suk; Lee, Jong-Cheol; Song, Chang Eun; Moon, Sang-Jin

    2017-10-18

    The reduction of charge carrier recombination and intrinsic defect density in organic-inorganic halide perovskite absorber materials is a prerequisite to achieving high-performance perovskite solar cells with good efficiency and stability. Here, we fabricated inverted planar perovskite solar cells by incorporation of a small amount of excess organic/inorganic halide (methylammonium iodide (CH3NH3I; MAI), formamidinium iodide (CH(NH2)2I; FAI), and cesium iodide (CsI)) in CH3NH3PbI3 perovskite film. Larger crystalline grains and enhanced crystallinity in CH3NH3PbI3 perovskite films with excess organic/inorganic halide reduce the charge carrier recombination and defect density, leading to enhanced device efficiency (MAI+: 14.49 ± 0.30%, FAI+: 16.22 ± 0.38% and CsI+: 17.52 ± 0.56%) compared to the efficiency of a control MAPbI3 device (MAI: 12.63 ± 0.64%) and device stability. Especially, the incorporation of a small amount of excess CsI in MAPbI3 perovskite film leads to a highly reproducible fill factor of over 83%, increased open-circuit voltage (from 0.946 to 1.042 V), and short-circuit current density (from 18.43 to 20.89 mA/cm2).

  16. Ternary Organic Solar Cells with Coumarin7 as the Donor Exhibiting Greater Than 10% Power Conversion Efficiency and a High Fill Factor of 75.

    Science.gov (United States)

    Chen, Xin-Wei; Tao, Si-Lu; Fan, Cong; Chen, Dong-Cheng; Zhou, Ling; Lin, Hui; Zheng, Cai-Jun; Su, Shi-Jian

    2017-09-06

    Ternary bulk heterojunction (BHJ) is a brilliant photovoltaic technology for improving the performance of organic solar cells (OSCs), because the light absorption range can be significantly extended by using multiple donors or acceptor materials. In this paper, coumarin7 (C7), a small organic molecule typical led used in organic light-emitting diodes, was initially exploited as second electron-donor component in ternary bulk heterojunction OSCs along with conventional blend system spolythieno[3,4-b]-thiophene/benzodithiophene(PTB7) and [6,6]-phenyl-C71 -butyric acid methyl(PC 71 BM). A champion PCE value of 10.28% was realized in the ternary OSCs when incorporated with 10 wt % C7 doping ratio in the donors, corresponding to about 35% enhancement compared with the PTB7:PC 71 BM-based OSCs, a high fill factor (FF) of 75.03%, a short-circuit currentdensity (J sc ) of 18.72 mA cm -2 and an open-circuit voltage (V oc ) of 0.73 V. The enhanced performance of the ternary OSCs can be attributed to the simultaneous improvement of the FF and the J sc . In addition to extended light absorption, a perfect nanofiber filament active layer morphology is obtained due to the good compatibility between C7 and PTB7, which facilitates the balance of charge transportation and the suppression of charge recombination. This investigation suggests that coumarin derivatives, which have completely different structure with polymer donors, can also be used to fabricate ternary solar cells and have the potential applications to obtain amazing performance after further device engineering and optimization.

  17. High-Order Hyperbolic Residual-Distribution Schemes on Arbitrary Triangular Grids

    Science.gov (United States)

    Mazaheri, Alireza; Nishikawa, Hiroaki

    2015-01-01

    In this paper, we construct high-order hyperbolic residual-distribution schemes for general advection-diffusion problems on arbitrary triangular grids. We demonstrate that the second-order accuracy of the hyperbolic schemes can be greatly improved by requiring the scheme to preserve exact quadratic solutions. We also show that the improved second-order scheme can be easily extended to third-order by further requiring the exactness for cubic solutions. We construct these schemes based on the LDA and the SUPG methodology formulated in the framework of the residual-distribution method. For both second- and third-order-schemes, we construct a fully implicit solver by the exact residual Jacobian of the second-order scheme, and demonstrate rapid convergence of 10-15 iterations to reduce the residuals by 10 orders of magnitude. We demonstrate also that these schemes can be constructed based on a separate treatment of the advective and diffusive terms, which paves the way for the construction of hyperbolic residual-distribution schemes for the compressible Navier-Stokes equations. Numerical results show that these schemes produce exceptionally accurate and smooth solution gradients on highly skewed and anisotropic triangular grids, including curved boundary problems, using linear elements. We also present Fourier analysis performed on the constructed linear system and show that an under-relaxation parameter is needed for stabilization of Gauss-Seidel relaxation.

  18. Cause and Cure - Deterioration in Accuracy of CFD Simulations With Use of High-Aspect-Ratio Triangular Tetrahedral Grids

    Science.gov (United States)

    Chang, Sin-Chung; Chang, Chau-Lyan; Venkatachari, Balaji Shankar

    2017-01-01

    Traditionally high-aspect ratio triangular/tetrahedral meshes are avoided by CFD re-searchers in the vicinity of a solid wall, as it is known to reduce the accuracy of gradient computations in those regions and also cause numerical instability. Although for certain complex geometries, the use of high-aspect ratio triangular/tetrahedral elements in the vicinity of a solid wall can be replaced by quadrilateral/prismatic elements, ability to use triangular/tetrahedral elements in such regions without any degradation in accuracy can be beneficial from a mesh generation point of view. The benefits also carry over to numerical frameworks such as the space-time conservation element and solution element (CESE), where triangular/tetrahedral elements are the mandatory building blocks. With the requirement of the CESE method in mind, a rigorous mathematical framework that clearly identities the reason behind the difficulties in use of such high-aspect ratio triangular/tetrahedral elements is presented here. As will be shown, it turns out that the degree of accuracy deterioration of gradient computation involving a triangular element is hinged on the value of its shape factor Gamma def = sq sin Alpha1 + sq sin Alpha2 + sq sin Alpha3, where Alpha1; Alpha2 and Alpha3 are the internal angles of the element. In fact, it is shown that the degree of accuracy deterioration increases monotonically as the value of Gamma decreases monotonically from its maximal value 9/4 (attained by an equilateral triangle only) to a value much less than 1 (associated with a highly obtuse triangle). By taking advantage of the fact that a high-aspect ratio triangle is not necessarily highly obtuse, and in fact it can have a shape factor whose value is close to the maximal value 9/4, a potential solution to avoid accuracy deterioration of gradient computation associated with a high-aspect ratio triangular grid is given. Also a brief discussion on the extension of the current mathematical framework to the

  19. Double-pattern triangular pulse width modulation technique for high-accuracy high-speed 3D shape measurement.

    Science.gov (United States)

    Wang, Yajun; Jiang, Chufan; Zhang, Song

    2017-11-27

    Using 1-bit binary patterns for three-dimensional (3D) shape measurement has been demonstrated as being advantageous over using 8-bit sinusoidal patterns in terms of achievable speeds. However, the phase quality generated by binary pattern(s) typically are not high if only a small number of phase-shifted patterns are used. This paper proposes a method to improve the phase quality by representing each pattern with the difference of two binary patterns: the first binary pattern is generated by triangular pulse width modulation (TPWM) technique, and the second being π shifted from the first pattern that is also generated by TPWM technique. The phase is retrieved by applying a three-step phase-shifting algorithm to the difference patterns. Through optimizing the modulation frequency of the triangular carrier signal, we demonstrate that a high-quality phase can be generated for a wide range of fringe periods (e.g., from 18 to 1140 pixels) with only six binary patterns. Since only 1-bit binary patterns are required for 3D shape measurement, this paper will present a real-time 3D shape measurement system that can achieve 30 Hz.

  20. Estimation of Image Sensor Fill Factor Using a Single Arbitrary Image

    Directory of Open Access Journals (Sweden)

    Wei Wen

    2017-03-01

    Full Text Available Achieving a high fill factor is a bottleneck problem for capturing high-quality images. There are hardware and software solutions to overcome this problem. In the solutions, the fill factor is known. However, this is an industrial secrecy by most image sensor manufacturers due to its direct effect on the assessment of the sensor quality. In this paper, we propose a method to estimate the fill factor of a camera sensor from an arbitrary single image. The virtual response function of the imaging process and sensor irradiance are estimated from the generation of virtual images. Then the global intensity values of the virtual images are obtained, which are the result of fusing the virtual images into a single, high dynamic range radiance map. A non-linear function is inferred from the original and global intensity values of the virtual images. The fill factor is estimated by the conditional minimum of the inferred function. The method is verified using images of two datasets. The results show that our method estimates the fill factor correctly with significant stability and accuracy from one single arbitrary image according to the low standard deviation of the estimated fill factors from each of images and for each camera.

  1. Effect of progressively increasing lithium conditioning on edge transport and stability in high triangularity NSTX H-modes

    Energy Technology Data Exchange (ETDEWEB)

    Maingi, R., E-mail: rmaingi@pppl.gov [Princeton Plasma Physics Laboratory, 100 Stellarator Road, Princeton, NJ 08543 (United States); Canik, J.M. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Bell, R.E. [Princeton Plasma Physics Laboratory, 100 Stellarator Road, Princeton, NJ 08543 (United States); Boyle, D.P. [Princeton University, Princeton, NJ (United States); Diallo, A.; Kaita, R.; Kaye, S.M.; LeBlanc, B.P. [Princeton Plasma Physics Laboratory, 100 Stellarator Road, Princeton, NJ 08543 (United States); Sabbagh, S.A. [Columbia University, New York, NY (United States); Scotti, F.; Soukhanovskii, V.A. [Lawrence Livermore National Laboratory, Livermore, CA (United States)

    2017-04-15

    A sequence of H-mode discharges with increasing levels of pre-discharge lithium evaporation (‘dose’) was conducted in high triangularity and elongation boundary shape in NSTX. Energy confinement increased, and recycling decreased with increasing lithium dose, similar to a previous lithium dose scan in medium triangularity and elongation plasmas. Data-constrained SOLPS interpretive modeling quantified the edge transport change: the electron particle diffusivity decreased by 10–30x. The electron thermal diffusivity decreased by 4x just inside the top of the pedestal, but increased by up to 5x very near the separatrix. These results provide a baseline expectation for lithium benefits in NSTX-U, which is optimized for a boundary shape similar to the one in this experiment.

  2. Effect of bismuth surfactant on InP-based highly strained InAs/InGaAs triangular quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Y.; Zhang, Y. G., E-mail: ygzhang@mail.sim.ac.cn; Chen, X. Y.; Xi, S. P.; Du, B.; Ma, Y. J. [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China)

    2015-11-23

    We report the effect of Bi surfactant on the properties of highly strained InAs/InGaAs triangular quantum wells grown on InP substrates. Reduced surface roughness, improved heterostructure interfaces and enhanced photoluminescence intensity at 2.2 μm are observed by moderate Bi-mediated growth. The nonradiative processes are analysed based on temperature-dependent photoluminescence. It is confirmed that Bi incorporation is insignificant in the samples, whereas excessive Bi flux during the growth results in deteriorated performance. The surfactant effect of Bi is promising to improve InP-based highly strained structures while the excess of Bi flux needs to be avoided.

  3. Simultaneous triangularization

    CERN Document Server

    Radjavi, Heydar

    2000-01-01

    A collection of matrices is said to be triangularizable if there is an invertible matrix S such that S1 AS is upper triangular for every A in the collection. This generalization of commutativity is the subject of many classical theorems due to Engel, Kolchin, Kaplansky, McCoy and others. The concept has been extended to collections of bounded linear operators on Banach spaces: such a collection is defined to be triangularizable if there is a maximal chain of subspaces of the Banach space, each of which is invariant under every member of the collection. Most of the classical results have been generalized to compact operators, and there are also recent theorems in the finite-dimensional case. This book is the first comprehensive treatment of triangularizability in both the finite and infinite-dimensional cases. It contains numerous very recent results and new proofs of many of the classical theorems. It provides a thorough background for research in both the linear-algebraic and operator-theoretic aspects of tr...

  4. Relationship between voice coil fill factor and loudspeaker efficiency

    DEFF Research Database (Denmark)

    Iversen, Niels Elkjær; Knott, Arnold; Andersen, Michael A. E.

    2016-01-01

    In modern audio systems, utilizing switch-mode amplifiers, the total efficiency is dominated by the rather poor efficiency of the loudspeaker. For decades voice coils have been designed so that nominal resistances of 3 to 8 Ω are obtained, despite modern audio amplifiers, using switch...... was measured to be 53 % which leaves plenty of room for future fill factor optimization....

  5. Quantum Hall Mach-Zehnder interferometer at fractional filling factors

    OpenAIRE

    Deviatov, E. V.; Egorov, S. V.; Biasiol, G.; Sorba, L.

    2012-01-01

    We use a Mach-Zehnder quantum Hall interferometer of a novel design to investigate the interference effects at fractional filling factors. Our device brings together the advantages of usual Mach-Zehnder and Fabry-Perot quantum Hall interferometers. It realizes the simplest-for-analysis Mach-Zehnder interference scheme, free from Coulomb blockade effects. By contrast to the standard Mach-Zehnder realization, our device does not contain an etched region inside the interference loop. For the fir...

  6. Cause and Cure-Deterioration in Accuracy of CFD Simulations with Use of High-Aspect-Ratio Triangular/Tetrahedral Grids

    Science.gov (United States)

    Chang, Sin-Chung; Chang, Chau-Lyan; Venkatachari, Balaji

    2017-01-01

    In the multi-dimensional space-time conservation element and solution element16 (CESE) method, triangles and tetrahedral mesh elements turn out to be the most natural building blocks for 2D and 3D spatial grids, respectively. As such, the CESE method is naturally compatible with the simplest 2D and 3D unstructured grids and thus can be easily applied to solve problems with complex geometries. However, because (a) accurate solution of a high-Reynolds number flow field near a solid wall requires that the grid intervals along the direction normal to the wall be much finer than those in a direction parallel to the wall and, as such, the use of grid cells with extremely high aspect ratio (103 to 106) may become mandatory, and (b) unlike quadrilateral hexahedral grids, it is well-known that accuracy of gradient computations involving triangular tetrahedral grids tends to deteriorate rapidly as cell aspect ratio increases. As a result, the use of triangular tetrahedral grid cells near a solid wall has long been deemed impractical by CFD researchers. In view of (a) the critical role played by triangular tetrahedral grids in the CESE development, and (b) the importance of accurate resolution of high-Reynolds number flow field near a solid wall, as will be presented in the main paper, a comprehensive and rigorous mathematical framework that clearly identifies the reasons behind the accuracy deterioration as described above has been developed for the 2D case involving triangular cells. By avoiding the pitfalls identified by the 2D framework, and its 3D extension, it has been shown numerically.

  7. Phasor analysis of binary diffraction gratings with different fill factors

    Energy Technology Data Exchange (ETDEWEB)

    MartInez, Antonio [Departamento de Ciencia de Materiales, Optica y TecnologIa Electronica, Universidad Miguel Hernandez, 03202 Elche (Spain); Sanchez-Lopez, Ma del Mar [Instituto de BioingenierIa y Departamento de Fisica y Arquitectura de Computadores, Universidad Miguel Hernandez, 03202 Elche (Spain); Moreno, Ignacio [Departamento de Ciencia de Materiales, Optica y TecnologIa Electronica, Universidad Miguel Hernandez, 03202 Elche (Spain)

    2007-09-11

    In this work, we present a simple analysis of binary diffraction gratings with different slit widths relative to the grating period. The analysis is based on a simple phasor technique directly derived from the Huygens principle. By introducing a slit phasor and a grating phasor, the intensity of the diffracted orders and the grating's resolving power can be easily obtained without applying the usual Fourier transform operations required for these calculations. The proposed phasor technique is mathematically equivalent to the Fourier transform calculation of the diffraction order amplitude, and it can be useful to explain binary diffraction gratings in a simple manner in introductory physics courses. This theoretical analysis is illustrated with experimental results using a liquid crystal device to display diffraction gratings with different fill factors.

  8. Measurements of elliptic and triangular flow in high-multiplicity $^{3}$He$+$Au collisions at $\\sqrt{s_{_{NN}}}=200$~GeV

    CERN Document Server

    Adare, A; Aidala, C; Ajitanand, N N; Akiba, Y; Akimoto, R; Al-Bataineh, H; Alexander, J; Alfred, M; Al-Ta'ani, H; Andrews, K R; Angerami, A; Aoki, K; Apadula, N; Aphecetche, L; Appelt, E; Aramaki, Y; Armendariz, R; Aronson, S H; Asai, J; Asano, H; Aschenauer, E C; Atomssa, E T; Averbeck, R; Awes, T C; Azmoun, B; Babintsev, V; Bai, M; Baksay, G; Baksay, L; Baldisseri, A; Bandara, N S; Bannier, B; Barish, K N; Barnes, P D; Bassalleck, B; Basye, A T; Bathe, S; Batsouli, S; Baublis, V; Baumann, C; Bazilevsky, A; Beaumier, M; Beckman, S; Belikov, S; Belmont, R; Ben-Benjamin, J; Bennett, R; Berdnikov, A; Berdnikov, Y; Bhom, J H; Bickley, A A; Blau, D S; Boissevain, J G; Bok, J S; Borel, H; Boyle, K; Brooks, M L; Broxmeyer, D; Bryslawskyj, J; Buesching, H; Bumazhnov, V; Bunce, G; Butsyk, S; Camacho, C M; Campbell, S; Caringi, A; Castera, P; Chang, B S; Chang, W C; Charvet, J -L; Chen, C -H; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J B; Choudhury, R K; Christiansen, P; Chujo, T; Chung, P; Churyn, A; Chvala, O; Cianciolo, V; Citron, Z; Cleven, C R; Cole, B A; Comets, M P; del Valle, Z Conesa; Connors, M; Constantin, P; Csanád, M; Csörgő, T; Dahms, T; Dairaku, S; Danchev, I; Danley, D; Das, K; Datta, A; Daugherity, M S; David, G; Dayananda, M K; Deaton, M B; DeBlasio, K; Dehmelt, K; Delagrange, H; Denisov, A; d'Enterria, D; Deshpande, A; Desmond, E J; Dharmawardane, K V; Dietzsch, O; Dion, A; Diss, P B; Do, J H; Donadelli, M; D'Orazio, L; Drapier, O; Drees, A; Drees, K A; Dubey, A K; Durham, J M; Durum, A; Dutta, D; Dzhordzhadze, V; Edwards, S; Efremenko, Y V; Egdemir, J; Ellinghaus, F; Emam, W S; Engelmore, T; Enokizono, A; En'yo, H; Esumi, S; Eyser, K O; Fadem, B; Feege, N; Fields, D E; Finger, M; Jr., \\,; Fleuret, F; Fokin, S L; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fujiwara, K; Fukao, Y; Fusayasu, T; Gadrat, S; Gal, C; Gallus, P; Garg, P; Garishvili, I; Ge, H; Giordano, F; Glenn, A; Gong, H; Gong, X; Gonin, M; Gosset, J; Goto, Y; de Cassagnac, R Granier; Grau, N; Greene, S V; Grim, G; Perdekamp, M Grosse; Gu, Y; Gunji, T; Guo, L; Gustafsson, H -Å; Hachiya, T; Henni, A Hadj; Haegemann, C; Haggerty, J S; Hahn, K I; Hamagaki, H; Hamblen, J; Hamilton, H F; Han, R; Han, S Y; Hanks, J; Harada, H; Harper, C; Hartouni, E P; Haruna, K; Hasegawa, S; Haseler, T O S; Hashimoto, K; Haslum, E; Hayano, R; He, X; Heffner, M; Hemmick, T K; Hester, T; Hiejima, H; Hill, J C; Hobbs, R; Hohlmann, M; Hollis, R S; Holzmann, W; Homma, K; Hong, B; Horaguchi, T; Hori, Y; Hornback, D; Hoshino, T; Hotvedt, N; Huang, J; Huang, S; Ichihara, T; Ichimiya, R; Iinuma, H; Ikeda, Y; Imai, K; Imrek, J; Inaba, M; Inoue, Y; Iordanova, A; Isenhower, D; Isenhower, L; Ishihara, M; Isobe, T; Issah, M; Isupov, A; Ivanishchev, D; Iwanaga, Y; Jacak, B V; Jezghani, M; Jia, J; Jiang, X; Jin, J; Jinnouchi, O; John, D; Johnson, B M; Jones, T; Joo, K S; Jouan, D; Jumper, D S; Kajihara, F; Kametani, S; Kamihara, N; Kamin, J; Kanda, S; Kaneta, M; Kaneti, S; Kang, B H; Kang, J H; Kang, J S; Kanou, H; Kapustinsky, J; Karatsu, K; Kasai, M; Kawall, D; Kawashima, M; Kazantsev, A V; Kempel, T; Key, J A; Khachatryan, V; Khanzadeev, A; Kijima, K M; Kikuchi, J; Kim, A; Kim, B I; Kim, C; Kim, D H; Kim, D J; Kim, E; Kim, E -J; Kim, G W; Kim, M; Kim, S H; Kim, Y -J; Kim, Y K; Kimelman, B; Kinney, E; Kiriluk, K; Kiss, Á; Kistenev, E; Kitamura, R; Kiyomichi, A; Klatsky, J; Klay, J; Klein-Boesing, C; Kleinjan, D; Kline, P; Koblesky, T; Kochenda, L; Kochetkov, V; Komkov, B; Konno, M; Koster, J; Kotchetkov, D; Kotov, D; Kozlov, A; Král, A; Kravitz, A; Kubart, J; Kunde, G J; Kurihara, N; Kurita, K; Kurosawa, M; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Lai, Y S; Lajoie, J G; Layton, D; Lebedev, A; Lee, D M; Lee, J; Lee, K B; Lee, K S; Lee, M K; Lee, S; Lee, S H; Lee, S R; Lee, T; Leitch, M J; Leite, M A L; Lenzi, B; Li, X; Lichtenwalner, P; Liebing, P; Lim, S H; Levy, L A Linden; Liška, T; Litvinenko, A; Liu, H; Liu, M X; Love, B; Lynch, D; Maguire, C F; Makdisi, Y I; Makek, M; Malakhov, A; Malik, M D; Manion, A; Manko, V I; Mannel, E; Mao, Y; Mašek, L; Masui, H; Matathias, F; McCumber, M; McGaughey, P L; McGlinchey, D; McKinney, C; Means, N; Meles, A; Mendoza, M; Meredith, B; Miake, Y; Mibe, T; Mignerey, A C; Mikeš, P; Miki, K; Miller, T E; Milov, A; Mioduszewski, S; Mishra, D K; Mishra, M; Mitchell, J T; Mitrovski, M; Miyachi, Y; Miyasaka, S; Mizuno, S; Mohanty, A K; Montuenga, P; Moon, H J; Moon, T; Morino, Y; Morreale, A; Morrison, D P; Motschwiller, S; Moukhanova, T V; Mukhopadhyay, D; Murakami, T; Murata, J; Mwai, A; Nagamiya, S; Nagashima, K; Nagata, Y; Nagle, J L; Naglis, M; Nagy, M I; Nakagawa, I; Nakagomi, H; Nakamiya, Y; Nakamura, K R; Nakamura, T; Nakano, K; Nam, S; Nattrass, C; Netrakanti, P K; Newby, J; Nguyen, M; Nihashi, M; Niida, T; Nishimura, S; Norman, B E; Nouicer, R; Novak, T; Novitzky, N; Nyanin, A S; Oakley, C; O'Brien, E; Oda, S X; Ogilvie, C A; Ohnishi, H; Oka, M; Okada, K; Omiwade, O O; Onuki, Y; Koop, J D Orjuela; Osborn, J D; Oskarsson, A; Ouchida, M; Ozawa, K; Pak, R; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, B H; Park, I H; Park, J; Park, J S; Park, S; Park, S K; Park, W J; Pate, S F; Patel, L; Patel, M; Pei, H; Peng, J -C; Pereira, H; Perepelitsa, D V; Perera, G D N; Peresedov, V; Peressounko, D Yu; Perry, J; Petti, R; Pinkenburg, C; Pinson, R; Pisani, R P; Proissl, M; Purschke, M L; Purwar, A K; Qu, H; Rak, J; Rakotozafindrabe, A; Ramson, B J; Ravinovich, I; Read, K F; Rembeczki, S; Reuter, M; Reygers, K; Reynolds, D; Riabov, V; Riabov, Y; Richardson, E; Rinn, T; Roach, D; Roche, G; Rolnick, S D; Romana, A; Rosati, M; Rosen, C A; Rosendahl, S S E; Rosnet, P; Rowan, Z; Rubin, J G; Rukoyatkin, P; Ružička, P; Rykov, V L; Sahlmueller, B; Saito, N; Sakaguchi, T; Sakai, S; Sakashita, K; Sakata, H; Sako, H; Samsonov, V; Sano, S; Sarsour, M; Sato, S; Sato, T; Savastio, M; Sawada, S; Schaefer, B; Schmoll, B K; Sedgwick, K; Seele, J; Seidl, R; Semenov, A Yu; Semenov, V; Sen, A; Seto, R; Sett, P; Sexton, A; Sharma, D; Shein, I; Shevel, A; Shibata, T -A; Shigaki, K; Shim, H H; Shimomura, M; Shoji, K; Shukla, P; Sickles, A; Silva, C L; Silvermyr, D; Silvestre, C; Sim, K S; Singh, B K; Singh, C P; Singh, V; Skutnik, S; Slunečka, M; Snowball, M; Sodre, T; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Suire, C; Sukhanov, A; Sumita, T; Sun, J; Sziklai, J; Tabaru, T; Takagi, S; Takagui, E M; Takahara, A; Taketani, A; Tanabe, R; Tanaka, Y; Taneja, S; Tanida, K; Tannenbaum, M J; Tarafdar, S; Taranenko, A; Tarján, P; Tennant, E; Themann, H; Thomas, D; Thomas, T L; Tieulent, R; Timilsina, A; Todoroki, T; Togawa, M; Toia, A; Tojo, J; Tomášek, L; Tomášek, M; Tomita, Y; Torii, H; Towell, C L; Towell, R; Towell, R S; Tram, V-N; Tserruya, I; Tsuchimoto, Y; Utsunomiya, K; Vale, C; Valle, H; van Hecke, H W; Vazquez-Zambrano, E; Veicht, A; Velkovska, J; Vértesi, R; Vinogradov, A A; Virius, M; Vossen, A; Vrba, V; Vznuzdaev, E; Wagner, M; Walker, D; Wang, X R; Watanabe, D; Watanabe, K; Watanabe, Y; Watanabe, Y S; Wei, F; Wei, R; Wessels, J; White, A S; White, S N; Winter, D; Woody, C L; Wright, R M; Wysocki, M; Xia, B; Xie, W; Xue, L; Yalcin, S; Yamaguchi, Y L; Yamaura, K; Yang, R; Yanovich, A; Yasin, Z; Ying, J; Yokkaichi, S; Yoo, J H; Yoo, J S; Yoon, I; You, Z; Young, G R; Younus, I; Yu, H; Yushmanov, I E; Zajc, W A; Zaudtke, O; Zelenski, A; Zhang, C; Zhou, S; Zimamyi, J; Zolin, L; Zou, L

    2015-01-01

    We present the first measurement of elliptic ($v_2$) and triangular ($v_3$) flow in high-multiplicity $^{3}$He$+$Au collisions at $\\sqrt{s_{_{NN}}}=200$~GeV. Two-particle correlations, where the particles have a large separation in pseudorapidity, are compared in $^{3}$He$+$Au and in $p$$+$$p$ collisions and indicate that collective effects dominate the second and third Fourier components for the correlations observed in the $^{3}$He$+$Au system. The collective behavior is quantified in terms of elliptic $v_2$ and triangular $v_3$ anisotropy coefficients measured with respect to their corresponding event planes. The $v_2$ values are comparable to those previously measured in $d$$+$Au collisions at the same nucleon-nucleon center-of-mass energy. Comparison with various theoretical predictions are made, including to models where the hot spots created by the impact of the three $^{3}$He nucleons on the Au nucleus expand hydrodynamically to generate the triangular flow. The agreement of these models with data may...

  9. Ultra-high sensitivity optical biosensor based on Vernier effect in triangular ring resonators (TRRs) with SPR

    Science.gov (United States)

    Kim, Tae-Ryong; Kim, Hong-Seung; Li, Jun; Oh, Geum-Yoon; Kim, Doo-Gun; Choi, Young-Wan

    2015-03-01

    In this paper, surface plasmon resonance triangular ring resonator (SPR-TRR) Vernier structure based on InP is simulated for index variation from 1.33 to 1.35. Sensing area of SPR-TRR is achieved to make an ultra-compact SPR mirror by deposition of Au film layer which is designed to deposit on vertex of TRR. The possibility of mass production is shown by a deposition of SPR mirror on the triangular ring resonator (TRR). Also, the sensitivity enhancement of an envelope signal for Vernier effect is confirmed by FDTD simulation compared to SPR-TRR. As simulation results, the sensitivity is enhanced 20 nm / RIU to 480 nm / RIU. Thus, SPR-TRR Vernier structure is used for a biosensor to enhance the sensitivity of biosensor.

  10. Heredity for triangular operators

    Directory of Open Access Journals (Sweden)

    Henry Crawford Rhaly Jr.

    2013-12-01

    Full Text Available A proof is given that if the lower triangular infinite matrix $T$ acts boundedly on $\\ell^2$ and U is the unilateral shift, the sequence $(U^*^nTU^n$ inherits from $T$ the following properties: posinormality, dominance, $M$-hyponormality, hyponormality, normality, compactness, and noncompactness.  Also, it is demonstrated that the upper triangular matrix $T^*$ is dominant if and only if $T$ is a diagonal matrix.

  11. The quantum Hall effect at 5/2 filling factor.

    Science.gov (United States)

    Willett, R L

    2013-07-01

    Experimental discovery of a quantized Hall state at 5/2 filling factor presented an enigmatic finding in an established field of study that has remained an open issue for more than twenty years. In this review we first examine the experimental requirements for observing this state and outline the initial theoretical implications and predictions. We will then follow the chronology of experimental studies over the years and present the theoretical developments as they pertain to experiments, directed at sets of issues. These topics will include theoretical and experimental examination of the spin properties at 5/2; is the state spin polarized? What properties of the higher Landau levels promote development of the 5/2 state, what other correlation effects are observed there, and what are their interactions with the 5/2 state? The 5/2 state is not a robust example of the fractional quantum Hall effect: what experimental and material developments have allowed enhancement of the effect? Theoretical developments from initial pictures have promoted the possibility that 5/2 excitations are exceptional; do they obey non-abelian statistics? The proposed experiments to determine this and their executions in various forms will be presented: this is the heart of this review. Experimental examination of the 5/2 excitations through interference measurements will be reviewed in some detail, focusing on recent results that demonstrate consistency with the picture of non-abelian charges. The implications of this in the more general physics picture is that the 5/2 excitations, shown to be non-abelian, should exhibit the properties of Majorana operators. This will be the topic of the last review section.

  12. Effect of operating current dependent series resistance on the fill factor of a solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Dadu, Meena; Kapoor, A.; Tripathi, K.N. [Department of Electronic Science, University of Delhi, South Campus, Benito Juarez road, -110 021 New Delhi (India)

    2002-02-01

    The fill factor of a solar cell depends upon the series resistance, reverse saturation current, diode quality factor, operating current and voltage. Since the series resistance itself depends upon the operating current (or voltage), it makes the evaluation of fill factor very complicated. In this paper, we have evaluated the fill factor of a solar cell, taking into account operating current dependence of the series resistance.

  13. Recent Development in the CESE Method for the Solution of the Navier-Stokes Equations Using Unstructured Triangular or Tetrahedral Meshes With High Aspect Ratio

    Science.gov (United States)

    Chang, Sin-Chung; Chang, Chau-Lyan; Yen, Joseph C.

    2013-01-01

    In the multidimensional CESE development, triangles and tetrahedra turn out to be the most natural building blocks for 2D and 3D spatial meshes. As such the CESE method is compatible with the simplest unstructured meshes and thus can be easily applied to solve problems with complex geometries. However, because the method uses space-time staggered stencils, solution decoupling may become a real nuisance in applications involving unstructured meshes. In this paper we will describe a simple and general remedy which, according to numerical experiments, has removed any possibility of solution decoupling. Moreover, in a real-world viscous flow simulation near a solid wall, one often encounters a case where a boundary with high curvature or sharp corner is surrounded by triangular/tetrahedral meshes of extremely high aspect ratio (up to 106). For such an extreme case, the spatial projection of a space-time compounded conservation element constructed using the original CESE design may become highly concave and thus its centroid (referred to as a spatial solution point) may lie far outside of the spatial projection. It could even be embedded beyond a solid wall boundary and causes serious numerical difficulties. In this paper we will also present a new procedure for constructing conservation elements and solution elements which effectively overcomes the difficulties associated with the original design. Another difficulty issue which was addressed more recently is the wellknown fact that accuracy of gradient computations involving triangular/tetrahedral grids deteriorates rapidly as the aspect ratio of grid cells increases. The root cause of this difficulty was clearly identified and several remedies to overcome it were found through a rigorous mathematical analysis. However, because of the length of the current paper and the complexity of mathematics involved, this new work will be presented in another paper.

  14. Inverted polymer solar cells with enhanced fill factor by inserting the potassium stearate interfacial modification layer

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jiangsheng [Institute of New Energy Technology, Ningbo Institute of Material Technology and Engineering (NIMTE), Chinese Academy of Science (CAS), Ningbo 315201 (China); Faculty of Materials Science and Chemical Engineering, Ningbo University, No. 818 Fenghua Road, Ningbo 315211 (China); Jiu, Tonggang, E-mail: jiutonggang@nimte.ac.cn, E-mail: fangjf@nimte.ac.cn; Li, Bairu; Kuang, Chaoyang; Chen, Qiushan; Ma, Sushuang; Fang, Junfeng, E-mail: jiutonggang@nimte.ac.cn, E-mail: fangjf@nimte.ac.cn [Institute of New Energy Technology, Ningbo Institute of Material Technology and Engineering (NIMTE), Chinese Academy of Science (CAS), Ningbo 315201 (China); Shu, Jie [Faculty of Materials Science and Chemical Engineering, Ningbo University, No. 818 Fenghua Road, Ningbo 315211 (China)

    2016-05-02

    A thin potassium stearate (KSt) film combined with an optimized ZnO film was introduced to improve the fill factor (FF) of highly efficient inverted polymer solar cells (PSCs). Atomic force microscopy and contact angle measurements were used to show that the introduction of KSt did not change the morphology of interlayer. On the contrary, it is beneficial for the spread of the active layer on the interlayer. The origin of enhanced FF was systematically studied by the ideal current-voltage model for a single heterojunction solar cell and electrochemical impedance spectroscopy. On the basis of the data analysis, the reduced charge recombination loss was responsible for this improved FF. At last, when KSt was replaced by sodium stearate (NaSt), the similar experiment phenomenon was observed. This indicates that inserting a metallic stearate modified layer is a promising strategy to enhance inverted PSCs performance.

  15. Inverted polymer solar cells with enhanced fill factor by inserting the potassium stearate interfacial modification layer

    Science.gov (United States)

    Li, Jiangsheng; Jiu, Tonggang; Li, Bairu; Kuang, Chaoyang; Chen, Qiushan; Ma, Sushuang; Shu, Jie; Fang, Junfeng

    2016-05-01

    A thin potassium stearate (KSt) film combined with an optimized ZnO film was introduced to improve the fill factor (FF) of highly efficient inverted polymer solar cells (PSCs). Atomic force microscopy and contact angle measurements were used to show that the introduction of KSt did not change the morphology of interlayer. On the contrary, it is beneficial for the spread of the active layer on the interlayer. The origin of enhanced FF was systematically studied by the ideal current-voltage model for a single heterojunction solar cell and electrochemical impedance spectroscopy. On the basis of the data analysis, the reduced charge recombination loss was responsible for this improved FF. At last, when KSt was replaced by sodium stearate (NaSt), the similar experiment phenomenon was observed. This indicates that inserting a metallic stearate modified layer is a promising strategy to enhance inverted PSCs performance.

  16. Effective variables to control the fill factor of organic photovoltaic cells.

    Science.gov (United States)

    Kim, Myung-Su; Kim, Bong-Gi; Kim, Jinsang

    2009-06-01

    Effective cell design variables having a large impact on the fill factor (FF) of organic photovoltaic cells (OPVCs) were systematically identified using a general device structure of ITO/PEDOT:PSS/P3HT + PCBM/LiF/Al. The results show that the characteristic properties of the organic layer, such as morphology and thickness, the regioregularity of the conjugated polymer, and the two interfaces between the electrodes and the blend layer have a large influence on the FF by affecting the series resistance (R(s)) and the shunt resistance (R(sh)). The systematic investigation described in this contribution provides a comprehensive understanding of the correlation between the device variables and R(s) and R(sh) and a way to control FF, which is critically important to achieving a high-performance OPVC.

  17. Subsonic high-angle-of-attack aerodynamic characteristics of a cone and cylinder with triangular cross sections and a cone with a square cross section

    Science.gov (United States)

    Clarkson, M. H.; Malcolm, G. N.; Brittain, V. A.; Intemann, P. A.

    1983-01-01

    Experiments were conducted in the 12-Foot Pressure Wind Tunnel at Ames Research Center on three models with noncircular cross sections: a cone having a square cross section with rounded corners and a cone and cylinder with triangular cross sections and rounded vertices. The cones were tested with both sharp and blunt noses. Surface pressures and force and moment measurements were obtained over an angle of attack range from 30 deg to 90 deg and selected oil-flow experiments were conducted to visualize surface flow patterns. Unit Reynolds numbers ranged from 0.8x1,000,000/m to 13.0x1,000,000/m at a Mach number of 0.25, except for a few low-Reynolds-number runs at a Mach number of 0.17. Pressure data, as well as force data and oil-flow photographs, reveal that the three dimensional flow structure at angles of attack up to 75 deg is very complex and is highly dependent on nose bluntness and Reynolds number. For angles of attack from 75 deg to 90 deg the sectional aerodynamic characteristics are similar to those of a two dimensional cylinder with the same cross section.

  18. Subdivision depth for triangular surfaces

    Directory of Open Access Journals (Sweden)

    G. Mustafa

    2016-06-01

    Full Text Available The aim of this attempt was to present an efficient algorithm for the evaluation of error bound of triangular subdivision surfaces. The error estimation technique is based on first order difference and this process is independent of parametrization. This technique can be easily generalized to higher arity triangular surfaces. The estimated error bound is expressed in-terms of initial control point sequence and constants. Here, we efficiently estimate error bound between triangular surface and its control polygon after k-fold subdivision and further extended to evaluate subdivision depth of the scheme.

  19. High-field recovery of the undistorted triangular lattice in the frustrated metamagnet CuFeO2

    NARCIS (Netherlands)

    Lummen, T. T. A.; Strohm, C.; Rakoto, H.; Nugroho, A. A.; van Loosdrecht, P. H. M.

    Pulsed-field magnetization experiments extend the typical metamagnetic staircase of CuFeO2 up to 58 T to reveal an additional first-order phase transition at high field for both the parallel and perpendicular field configuration. Virtually complete isotropic behavior is retrieved only above this

  20. Simultaneous enhancement of open-circuit voltage, short-circuit current density, and fill factor in polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    He, Zhicai; Zhong, Chengmei; Wu, Hongbin; Su, Shijian; Cao, Yong [Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640 (China); Huang, Xun; Chen, Liwei [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, 398 Ruoshui Road, Suzhou Industrial Park, Suzhou 215123 (China); Wong, Wai-Yeung [Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee, Hong Kong) and Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Hong Kong (China)

    2011-10-25

    Simultaneous enhancement of open-circuit voltage, short-circuit current density, and fill factor in highly efficient polymer solar cells by incorporating an alcohol/water-soluble conjugated polymer as cathode interlayer is domonstrated. When combined with a low-bandgap polymer PTB7 as the electron donor material, the power efficiency of the devices is improved to certified 8.370%. Due to drastic improvement in efficiency and easy utilization, this method opens new opportunities for PSCs from various material systems to improve towards 10% efficiency. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Unveiling square and triangular optical lattices: a comparative study.

    Science.gov (United States)

    Silva, Juarez G; Jesus-Silva, Alcenísio J; Alencar, Márcio A R C; Hickmann, Jandir M; Fonseca, Eduardo J S

    2014-02-15

    We study square and triangular optical lattice formation using a diffraction technique with light-possessing orbital angular momentum (OAM). We demonstrate that it is possible to use Fraunhofer diffraction of light by a square aperture to unveil OAM about two times bigger than would be possible with a triangular aperture. We notice that the pattern remains truncated until a topological charge (TC) equal to 20 with good precision. Even though a square pattern cannot be used to determine the TC sign, it is possible to measure high order of the modulus and sign of the TC up to 20, combining patterns of the triangular and square apertures.

  2. Light propagation in optical crystal powders: effects of particle size and volume filling factor

    Energy Technology Data Exchange (ETDEWEB)

    GarcIa-Ramiro, B [Departamento de Fisica Aplicada I, Escuela Tecnica Superior de IngenierIa, Universidad del PaIs Vasco, Alameda Urquijo s/n, 48013 Bilbao (Spain); Illarramendi, M A [Departamento de Fisica Aplicada I, Escuela Tecnica Superior de IngenierIa, Universidad del PaIs Vasco, Alameda Urquijo s/n, 48013 Bilbao (Spain); Aramburu, I [Departamento de Fisica Aplicada I, Escuela Tecnica Superior de IngenierIa, Universidad del PaIs Vasco, Alameda Urquijo s/n, 48013 Bilbao (Spain); Fernandez, J [Departamento de Fisica Aplicada I, Escuela Tecnica Superior de IngenierIa, Universidad del PaIs Vasco, Alameda Urquijo s/n, 48013 Bilbao (Spain); Balda, R [Departamento de Fisica Aplicada I, Escuela Tecnica Superior de IngenierIa, Universidad del PaIs Vasco, Alameda Urquijo s/n, 48013 Bilbao (Spain); Al-Saleh, M [Departamento de Fisica Aplicada I, Escuela Tecnica Superior de IngenierIa, Universidad del PaIs Vasco, Alameda Urquijo s/n, 48013 Bilbao (Spain)

    2007-11-14

    In this work, we analyse the light propagation in some laser and nonlinear crystal powders. In particular, we study the dependence of the diffusive absorption lengths and the transport lengths on particle size and volume filling factor. The theoretical calculations have been made by assuming a diffusive propagation of light in these materials.

  3. Accurate expressions for solar cell fill factors including series and shunt resistances

    Science.gov (United States)

    Green, Martin A.

    2016-02-01

    Together with open-circuit voltage and short-circuit current, fill factor is a key solar cell parameter. In their classic paper on limiting efficiency, Shockley and Queisser first investigated this factor's analytical properties showing, for ideal cells, it could be expressed implicitly in terms of the maximum power point voltage. Subsequently, fill factors usually have been calculated iteratively from such implicit expressions or from analytical approximations. In the absence of detrimental series and shunt resistances, analytical fill factor expressions have recently been published in terms of the Lambert W function available in most mathematical computing software. Using a recently identified perturbative relationship, exact expressions in terms of this function are derived in technically interesting cases when both series and shunt resistances are present but have limited impact, allowing a better understanding of their effect individually and in combination. Approximate expressions for arbitrary shunt and series resistances are then deduced, which are significantly more accurate than any previously published. A method based on the insights developed is also reported for deducing one-diode fits to experimental data.

  4. Ultrasound fields from triangular apertures

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    1996-01-01

    The pulsed field from a triangular aperture mounted in an infinite, rigidbaffle is calculated. The approach of spatial impulse responses,as developed by Tupholme and Stepanishen, is used. By this both the emitted and received pulsed ultrasound field can be found for any transducerexcitation...

  5. On the collective mode spectrum for composite fermions at 1/3 filling factor

    CERN Document Server

    Pérez-Martínez, A; Guerra, V; Martinez, Aurora Perez; Cabo, Alejandro; Guerra, Valia

    1995-01-01

    The collective mode spectrum of the composite fermion state 1/3 filling factor is evaluated. At zero momentum, the result coincides with the cyclotron energy at the external magnetic field value, and not at the effective magnetic field, in spite of the fact that only the former enters in the equations, thus, the Kohn theorem is satisfied. Unexpectedly, in place of a magneto roton minimum, the collective mode gets a treshold indicating the instability of the mean field composite fermion state under the formation of crystalline structures. However, the question about if if this outcome only appears within the mean field approximation should be further considered.

  6. Redesigning Triangular Dense Matrix Computations on GPUs

    KAUST Repository

    Charara, Ali

    2016-08-09

    A new implementation of the triangular matrix-matrix multiplication (TRMM) and the triangular solve (TRSM) kernels are described on GPU hardware accelerators. Although part of the Level 3 BLAS family, these highly computationally intensive kernels fail to achieve the percentage of the theoretical peak performance on GPUs that one would expect when running kernels with similar surface-to-volume ratio on hardware accelerators, i.e., the standard matrix-matrix multiplication (GEMM). The authors propose adopting a recursive formulation, which enriches the TRMM and TRSM inner structures with GEMM calls and, therefore, reduces memory traffic while increasing the level of concurrency. The new implementation enables efficient use of the GPU memory hierarchy and mitigates the latency overhead, to run at the speed of the higher cache levels. Performance comparisons show up to eightfold and twofold speedups for large dense matrix sizes, against the existing state-of-the-art TRMM and TRSM implementations from NVIDIA cuBLAS, respectively, across various GPU generations. Once integrated into high-level Cholesky-based dense linear algebra algorithms, the performance impact on the overall applications demonstrates up to fourfold and twofold speedups, against the equivalent native implementations, linked with cuBLAS TRMM and TRSM kernels, respectively. The new TRMM/TRSM kernel implementations are part of the open-source KBLAS software library (http://ecrc.kaust.edu.sa/Pages/Res-kblas.aspx) and are lined up for integration into the NVIDIA cuBLAS library in the upcoming v8.0 release.

  7. Anisotropic Adhesion Properties of Triangular-Tip-Shaped Micropillars

    KAUST Repository

    Kwak, Moon Kyu

    2011-06-01

    Directional dry adhesive microstructures consisting of high-density triangular-tip-shaped micropillars are described. The wide-tip structures allow for unique directional shear adhesion properties with respect to the peeling direction, along with relatively high normal adhesion. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Limits on the Fill Factor in Organic Photovoltaics: Distinguishing Nongeminate and Geminate Recombination Mechanisms.

    Science.gov (United States)

    Dibb, George F A; Jamieson, Fiona C; Maurano, Andrea; Nelson, Jenny; Durrant, James R

    2013-03-07

    In this Letter, we present transient optoelectronic experimental studies of the recombination processes limiting the fill factor (FF) in three conjugated polymer:fullerene systems, poly(3-hexylthiophene) (P3HT) and two lower-band-gap polymers that exhibit lower FFs poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7-(2,1,3-benzothiadiazole) (PCPDTBT) and poly(2,7-(9,9-dioctylfluorene)-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)) (APFO-3). Using transient absorption spectroscopy, charge extraction, and transient photovoltage experiments, we show that the lower FF observed for the PCPDTBT-based device results from enhanced nongeminate recombination even at short circuit, In contrast, we show that for APFO-3 devices, the FF is primarily limited by a voltage-dependent free charge generation, which we assign to a geminate recombination process.

  9. Watching systems of triangular graphs

    Directory of Open Access Journals (Sweden)

    Maryam Roozbayani

    2014-03-01

    Full Text Available A watching system in a graph $G=(V, E$ is a set $W={omega_{1}, omega_{2}, cdots, omega_{k}}$, where $omega_{i}=(v_{i}, Z_{i}, v_{i}in V$ and $Z_{i}$ is a subset of closed neighborhood of $v_{i}$ such that the sets $L_{W}(v={omega_{i}: vin omega_{i}}$ are non-empty and distinct, for any $vin V$. In this paper, we study the watching systems of line graph $K_{n}$ which is called triangular graph and denoted by $T(n$. The minimum size of a watching system of $G$ is denoted by $omega(G$. We show that $omega(T(n=lceilfrac{2n}{3}rceil$.

  10. Magnetic focusing in triangular electron billiards

    DEFF Research Database (Denmark)

    Bøggild, Peter; Kristensen, A.; Lindelof, Poul Erik

    1999-01-01

    The classical ballistic magnetotransport in triangular electron billiards fabricated in a high mobility GaAs heterostructure has been studied at 4.2 K. The sample geometry may be viewed as a double-slit structure with a skewed injection angle. We observe a striking cancellation of the magnetic...... is remarkably sensitive to the angular distribution of injected electrons as well as the overall injection angle. [S0163-1829(99)06619-9]....... focusing spectrum compared to the case of a perpendicular injection angle. From numerical and analytical analysis, we confirm that the quenching is a fundamental geometrical effect, and identify two mechanisms responsible for the anomaly. The focusing spectrum of the considered skewed geometry...

  11. Modified spin-wave theory and spin-liquid behavior of cold bosons on an inhomogeneous triangular lattice

    Science.gov (United States)

    Celi, Alessio; Grass, Tobias; Ferris, Andrew J.; Padhi, Bikash; Raventós, David; Simonet, Juliette; Sengstock, Klaus; Lewenstein, Maciej

    2016-08-01

    Ultracold bosons in a triangular lattice are a promising candidate for observing quantum spin liquid behavior. Here we investigate, for such system, the role of a harmonic trap giving rise to an inhomogeneous density. We construct a modified spin-wave theory for arbitrary filling and predict the breakdown of order for certain values of the lattice anisotropy. These regimes, identified with the spin liquid phases, are found to be quite robust upon changes in the filling factor. This result is backed by an exact diagonalization study on a small lattice.

  12. Interconnect patterns for printed organic thermoelectric devices with large fill factors

    Science.gov (United States)

    Gordiz, Kiarash; Menon, Akanksha K.; Yee, Shannon K.

    2017-09-01

    Organic materials can be printed into thermoelectric (TE) devices for low temperature energy harvesting applications. The output voltage of printed devices is often limited by (i) small temperature differences across the active materials attributed to small leg lengths and (ii) the lower Seebeck coefficient of organic materials compared to their inorganic counterparts. To increase the voltage, a large number of p- and n-type leg pairs is required for organic TEs; this, however, results in an increased interconnect resistance, which then limits the device output power. In this work, we discuss practical concepts to address this problem by positioning TE legs in a hexagonal closed-packed layout. This helps achieve higher fill factors (˜91%) than conventional inorganic devices (˜25%), which ultimately results in higher voltages and power densities due to lower interconnect resistances. In addition, wiring the legs following a Hilbert spacing-filling pattern allows for facile load matching to each application. This is made possible by leveraging the fractal nature of the Hilbert interconnect pattern, which results in identical sub-modules. Using the Hilbert design, sub-modules can better accommodate non-uniform temperature distributions because they naturally self-localize. These device design concepts open new avenues for roll-to-roll printing and custom TE module shapes, thereby enabling organic TE modules for self-powered sensors and wearable electronic applications.

  13. Spectral properties of random triangular matrices

    OpenAIRE

    Basu, Riddhipratim; Bose, Arup; Ganguly, Shirshendu; Hazra, Rajat Subhra

    2011-01-01

    We prove the existence of the limiting spectral distribution (LSD) of symmetric triangular patterned matrices and also establish the joint convergence of sequences of such matrices. For the particular case of the symmetric triangular Wigner matrix, we derive expression for the moments of the LSD using properties of Catalan words. The problem of deriving explicit formulae for the moments of the LSD does not seem to be easy to solve for other patterned matrices. The LSD of the non-symmetric tri...

  14. THE SPECTRUM OF AMALRIC TRIANGULAR CHOROIDAL INFARCTION.

    Science.gov (United States)

    Nemiroff, Julia; Phasukkijwatana, Nopasak; Vaclavik, Veronika; Nagiel, Aaron; Holz, Eric R; Sarraf, David

    2017-01-01

    To describe the multimodal imaging findings, including optical coherence tomography angiography analysis, and spectrum of etiologies associated with Amalric triangular choroidal infarction. This study is a multicenter, retrospective, observational case series review of the clinical and multimodal imaging findings for six patients with Amalric triangular choroidal infarction. Six patients (10 eyes) with Amalric triangular choroidal infarction were enrolled. Patients' ages ranged from 7 years to 90 years (mean 54 years, median 60 years). Wedge-shaped or triangular areas of choroidal ischemia were evident with fluorescein angiography in all patients and with indocyanine green angiography in one patient. Optical coherence tomography angiography demonstrated choriocapillaris flow reduction that colocalized with outer retinal structural abnormalities with en face optical coherence tomography and corresponded with the triangular zones of choroidal infarction identified with fluorescein angiography in one patient. Etiologies included giant cell arteritis in three cases: traumatic carotid dissection, traumatic retrobulbar hemorrhage, and malignant hypertension secondary to lupus-associated nephropathy. The Amalric triangular syndrome of choroidal infarction can occur as a result of a spectrum of etiologies, especially giant cell arteritis. Infarction is evident on traditional angiography in all cases. Optical coherence tomography angiography may provide a simple noninvasive tool to evaluate choroidal ischemia.

  15. Study of external quantum efficiency of plasmonic coupled bilayer active device: influence of layer thickness and nanoparticle filling factor

    Science.gov (United States)

    Pathak, Nilesh Kumar; Pathak, Hardik; Pandey, Gyanendra Krishna; Ji, Alok; Sharma, R. P.

    2016-12-01

    To improve the efficiency of organic-inorganic photovoltaic devices, the inclusion of metal nanoparticles such as silver has been used to enhance photon absorption. Incorporation of silver nanoparticle into the active layer with various filling factor increases the exciton generation rate of active material. The exciton-plasmon coupling mechanism are analysed in terms of effective absorption coefficient via Maxwell Garnett theory including size effect. To obtain the exciton population of organic-inorganic heterojunction device with nanoparticle embedded into inorganic layer, we have solved one-dimensional steady-state exciton diffusion equation. On the basis of this, we have calculated the expression of photocurrent and external quantum efficiency with and without plasmonic effects under the influences of standard AM 1.5 solar spectrums. After embedding the silver nanoparticle (with filling factor 0.55) into inorganic active layer, optimum enhancement in the external quantum efficiency by 4.90% has been found as compared to reference device.

  16. Parabolic similariton Yb-fiber laser with triangular pulse evolution

    Science.gov (United States)

    Wang, Sijia; Wang, Lei

    2016-04-01

    We propose a novel mode-locked fiber laser design which features a passive nonlinear triangular pulse formation and self-similar parabolic pulse amplification intra cavity. Attribute to the nonlinear reshaping progress in the passive fiber, a triangular-profiled pulse with negative-chirp is generated and paved the way for rapid and efficient self-similar parabolic evolution in a following short-length high-gain fiber. In the meanwhile, the accompanied significantly compressed narrow spectrum from this passive nonlinear reshaping also gives the promise of pulse stabilization and gain-shaping robustness without strong filtering. The resulting short average intra-cavity pulse duration, low amplified spontaneous emission (ASE) and low intra-cavity power loss are essential for the low-noise operation. Simulations predict this modelocked fiber laser allows for high-energy ultra-short transform-limited pulse generation exceeding the gain bandwidth. The output pulse has a de-chirped duration (full-width at half maximum, FWHM) of 27 fs. In addition to the ultrafast laser applications, the proposed fiber laser scheme can support low-noise parabolic and triangular pulse trains at the same time, which are also attractive in optical pulse shaping, all-optical signal processing and high-speed communication applications.

  17. On the Construction of Jointly Superregular Lower Triangular Toeplitz Matrices

    DEFF Research Database (Denmark)

    Hansen, Jonas; Østergaard, Jan; Kudahl, Johnny

    2016-01-01

    Superregular matrices have the property that all of their submatrices, which can be full rank are so. Lower triangular superregular matrices are useful for e.g., maximum distance separable convolutional codes as well as for (sequential) network codes. In this work, we provide an explicit design...... for all superregular lower triangular Toeplitz matrices in GF(2p) for the case of matrices with dimensions less than or equal to 5 × 5. For higher dimensional matrices, we present a greedy algorithm that find a solution provided the field size is sufficiently high. We also introduce the notions of jointly...... superregular and product preserving jointly superregular matrices, and extend our explicit constructions of superregular matrices to these cases. Jointly superregular matrices are necessary to achieve optimal decoding capabilities for the case of codes with a rate lower than 1/2, and the product preserving...

  18. Tridirectional Polarization Routing of Light by a Single Triangular Plasmonic Nanoparticle.

    Science.gov (United States)

    Tanaka, Yoshito Y; Shimura, Tsutomu

    2017-05-10

    Achieving high directionality of scattered light in combination with high flexibility of the direction using plasmonic nanoparticles is desirable for future optical nanocircuits and on-chip optical links. The plasmonic characteristics of nanoparticles strongly depend on their geometry. Here, we studied directional light scattering by a single-element triangular plasmonic nanoparticle. Our experimental and simulation results demonstrated that the triangular nanoparticle spatially sorted the incoming photons into three different scattering directions according to their polarization direction, including circular polarization, despite its compact overall volume of ∼λ3/300. The broken mirror symmetry and rotational symmetry of the triangular nanoparticle enabled such passive tridirectional polarization routing through the constructive and destructive interference of different plasmon modes. Our findings should markedly broaden the versatility of triangular plasmonic nanodevices, extending their possible practical applications in photon couplers and sorters and chemo-/biosensors.

  19. Technical innovation for noninvasive and early diagnosis of biliary atresia: the ultrasonographic "triangular cord" sign.

    Science.gov (United States)

    Park, W H; Choi, S O; Lee, H J

    2001-01-01

    In this article, we introduce our experience regarding a new and noninvasive diagnostic tool, using ultrasonography, for the early and definite diagnosis of biliary atresia. We have focussed on the ultrasonographic image of the cone-shaped periportal fibrous mass in infants with biliary atresia since 1992, and have finally identified a triangular or band-like periportal echogenicity ("triangular cord" sign), mainly cranial to the portal vein. Based on our experience and other reports from Japan and Singapore, the ultrasonographic triangular cord sign is a simple, time-saving, highly reliable, and definite tool in the diagnosis of biliary atresia from infantile intrahepatic cholestasis, representing a positive predictive value greater than 95%. We have proposed a new diagnostic strategy in the evaluation of infantile cholestasis, with emphasis on the ultrasonographic triangular cord sign.

  20. LAMINAR NATURAL CONVECTION IN TRIANGULAR ENCLOSURES

    OpenAIRE

    Kent, Emin Fuad

    2016-01-01

    Natural convection in non-rectangular enclosures is numerically analyzed in this study. Streamlines and isotherms are presented for different triangular enclosures with different boundary conditions and Rayleigh numbers. Mean Nusselt numbers on hot walls are also calculated in order to make comparisons between different cases.

  1. Heat transfer characteristics of rotating triangular thermosyphon

    Science.gov (United States)

    Ibrahim, E.; Moawed, M.; Berbish, N. S.

    2012-09-01

    An experimental investigation is carried out to study heat transfer characteristics of a rotating triangular thermosyphon, using R-134a refrigerant as the working fluid. The tested thermosyphon is an equilateral triangular tube made from copper material of 11 mm triangular length, 2 mm thickness, and a total length of 1,500 mm. The length of the evaporator section is 600 mm, adiabatic section is 300 mm, and condenser section is 600 mm. The effects of the rotational speed, filling ratio, and the evaporator heat flux on each of the evaporator heat transfer coefficient, he, condenser heat transfer coefficient, hc, and the overall effective thermal conductance, Ct are studied. Experiments are performed with a vertical position of thermosyphon within heat flux ranges from 11 to 23 W/m2 for the three selected filling ratios of 10, 30 and 50 % of the evaporator section volume. The results indicated that the maximum values of the tested heat transfer parameters of the rotational equilateral triangular thermosyphon are obtained at the filling ratio of 30 %. Also, it is found that the heat transfer coefficient of the condensation is increased with increasing the rotational speed. The tested heat transfer parameters of the thermosyphon are correlated as a function of the evaporator heat flux and angular velocity.

  2. Understanding the microstructures of triangular defects in 4H-SiC homoepitaxial

    Science.gov (United States)

    Guo, Jianqiu; Yang, Yu; Raghothamachar, Balaji; Kim, Taejin; Dudley, Michael; Kim, Jungyu

    2017-12-01

    Triangular defects are frequently observed in 4H-SiC homoepitaxial layers and their existence is reported to greatly degrade the performance of corresponding p-n junction diodes. Regarding the formation mechanisms of these defects, there have been a few models postulated before, which will be briefly reviewed here. In this study, we have observed a significant number of triangular defects in a 150mm n-/n+ commercial 4H-SiC homoepitaxial wafer using Nomarski Microscopy and Synchrotron X-ray topography (SXRT). The observed defects show varying morphology and complexity. In order to investigate their complex microstructures and gain insight on the formation mechanism, selected triangular defects were characterized by high resolution transmission electron microscopy (HRTEM) and micro-Raman spectroscopy. Results confirm that all the triangular defects have a 3C-SiC nature. In addition, { 1 1 1 } twins and double positioning boundaries (DPBs) were frequently observed inside the triangular defects. Based on these observations, a model has been developed to interpret the formation mechanism of these defects. In this model, the introduction of downfall particle during epitaxy creates a large triangular on-axis terrace, on which 3C-SiC crystals nucleate 2-dimensionally and grow under no constraint, eventually overgrown by 4H-SiC growth steps.

  3. Marginally Stable Triangular Recurrent Neural Network Architecture for Time Series Prediction.

    Science.gov (United States)

    Sivakumar, Seshadri; Sivakumar, Shyamala

    2017-09-25

    This paper introduces a discrete-time recurrent neural network architecture using triangular feedback weight matrices that allows a simplified approach to ensuring network and training stability. The triangular structure of the weight matrices is exploited to readily ensure that the eigenvalues of the feedback weight matrix represented by the block diagonal elements lie on the unit circle in the complex z-plane by updating these weights based on the differential of the angular error variable. Such placement of the eigenvalues together with the extended close interaction between state variables facilitated by the nondiagonal triangular elements, enhances the learning ability of the proposed architecture. Simulation results show that the proposed architecture is highly effective in time-series prediction tasks associated with nonlinear and chaotic dynamic systems with underlying oscillatory modes. This modular architecture with dual upper and lower triangular feedback weight matrices mimics fully recurrent network architectures, while maintaining learning stability with a simplified training process. While training, the block-diagonal weights (hence the eigenvalues) of the dual triangular matrices are constrained to the same values during weight updates aimed at minimizing the possibility of overfitting. The dual triangular architecture also exploits the benefit of parsing the input and selectively applying the parsed inputs to the two subnetworks to facilitate enhanced learning performance.

  4. Triangular springs for modeling nonlinear membranes.

    Science.gov (United States)

    Delingette, Hervé

    2008-01-01

    This paper provides a formal connexion between springs and continuum mechanics in the context of one-dimensional and two-dimensional elasticity. In a first stage, the equivalence between tensile springs and the finite element discretization of stretching energy on planar curves is established. Furthermore, when considering a quadratic strain function of stretch, we introduce a new type of springs called tensile biquadratic springs. In a second stage, we extend this equivalence to non-linear membranes (St Venant-Kirchhoff materials) on triangular meshes leading to triangular biquadratic and quadratic springs. Those tensile and angular springs produce isotropic deformations parameterized by Young modulus and Poisson ratios on unstructured meshes in an efficient and simple way. For a specific choice of the Poisson ratio, 0.3, we show that regular spring-mass models may be used realistically to simulate a membrane behavior. Finally, the different spring formulations are tested in pure traction and cloth simulation experiments.

  5. Maxima of Skew Elliptical Triangular Arrays

    OpenAIRE

    Hashorva, Enkelejd; Ling, Chengxiu

    2013-01-01

    In this paper we investigate the asymptotic behaviour of the componentwise maxima for two bivariate skew elliptical triangular arrays with components given in terms of skew transformations of bivariate spherical random vectors. We find the weak limit of the normalized maxima for both cases that the random radius pertaining to the elliptical random vectors is either in the Gumbel or in the Weibull max-domain of attractions.

  6. A framework for dense triangular matrix kernels on various manycore architectures

    KAUST Repository

    Charara, Ali

    2017-06-06

    We present a new high-performance framework for dense triangular Basic Linear Algebra Subroutines (BLAS) kernels, ie, triangular matrix-matrix multiplication (TRMM) and triangular solve (TRSM), on various manycore architectures. This is an extension of a previous work on a single GPU by the same authors, presented at the EuroPar\\'16 conference, in which we demonstrated the effectiveness of recursive formulations in enhancing the performance of these kernels. In this paper, the performance of triangular BLAS kernels on a single GPU is further enhanced by implementing customized in-place CUDA kernels for TRMM and TRSM, which are called at the bottom of the recursion. In addition, a multi-GPU implementation of TRMM and TRSM is proposed and we show an almost linear performance scaling, as the number of GPUs increases. Finally, the algorithmic recursive formulation of these triangular BLAS kernels is in fact oblivious to the targeted hardware architecture. We, therefore, port these recursive kernels to homogeneous x86 hardware architectures by relying on the vendor optimized BLAS implementations. Results reported on various hardware architectures highlight a significant performance improvement against state-of-the-art implementations. These new kernels are freely available in the KAUST BLAS (KBLAS) open-source library at https://github.com/ecrc/kblas.

  7. ESR in 2D triangular chromium lattices

    Energy Technology Data Exchange (ETDEWEB)

    Hemmida, M; Nidda, H-A Krug von; Loidl, A, E-mail: mhemmida@yahoo.d [Experimental Physics V, Center for Electronic Correlations and Magnetism, University of Augsburg, 86135 Augsburg (Germany)

    2010-01-01

    The spin dynamics in some two-dimensional (2D) triangular Cr-antiferromagnetic frustrated lattices, i.e. HCrO{sub 2}, LiCrO{sub 2}, and NaCrO{sub 2} with ordered rock-salt structure as well as the delafossite compounds CuCrO{sub 2} and AgCrO{sub 2}, has been investigated by Electron Spin Resonance (ESR). On approaching the Neel temperature T{sub N} from above, the divergence of the temperature dependent linewidth is well described in terms of a Berezinskii-Kosterlitz-Thouless (BKT) like scenario due to magnetic vortex-antivortex pairing.

  8. Triangular Geometrized Sampling Heuristics for Fast Optimal Motion Planning

    Directory of Open Access Journals (Sweden)

    Ahmed Hussain Qureshi

    2015-02-01

    Full Text Available Rapidly-exploring Random Tree (RRT-based algorithms have become increasingly popular due to their lower computational complexity as compared with other path planning algorithms. The recently presented RRT* motion planning algorithm improves upon the original RRT algorithm by providing optimal path solutions. While RRT determines an initial collision-free path fairly quickly, RRT* guarantees almost certain convergence to an optimal, obstacle-free path from the start to the goal points for any given geometrical environment. However, the main limitations of RRT* include its slow processing rate and high memory consumption, due to the large number of iterations required for calculating the optimal path. In order to overcome these limitations, we present another improvement, i.e, the Triangular Geometerized-RRT* (TG-RRT* algorithm, which utilizes triangular geometrical methods to improve the performance of the RRT* algorithm in terms of the processing time and a decreased number of iterations required for an optimal path solution. Simulations comparing the performance results of the improved TG-RRT* with RRT* are presented to demonstrate the overall improvement in performance and optimal path detection.

  9. Simple haptotactic gradient generation within a triangular microfluidic channel.

    Science.gov (United States)

    Park, Jungyul; Kim, Deok-Ho; Kim, Gabriel; Kim, Younghoon; Choi, Eunpyo; Levchenko, Andre

    2010-08-21

    Most microfluidic devices developed to date for the analysis of live cells incorporate channels with relatively simple constant rectangular or semi-circular cross-sections, relying on complex channel network geometries rather than alteration of the shapes of the channels themselves for development of diverse functional fluidic controls, e.g., spatial gradients of bioactive ligands. In this study we describe a simple alternative method to create highly defined and predictable gradients of surface bound molecules. This method relies on the generation of a considerable variation in the spatial distribution of flow velocities within a channel with a triangular cross-section. The triangular shape can be easily implemented by using bulk wet etching and polydimethylsiloxane (PDMS) replica molding techniques. By analytical modeling and simulation, we predict that the deposition of the solute onto a channel boundary depends on the local flow rate values, yielding gradient spanning the whole width of the channel. This prediction was validated by direct visualization of the flow rate and fibronectin-rhodamine deposition in a fabricated microchannel. Using this experimental platform, we assessed cell migration in response to a fibronectin gradient deposited in the microchannels. We find that this gradient could induce robust haptotaxis of Chinese Hamster Ovary (CHO) cells towards the areas of higher fibronectin surface density. We propose that the described simple gradient generation method can help to avoid complexity present in many current device designs, allowing to introduce more easily other potentially useful design features.

  10. Use of dermoscopy in the diagnosis of temporal triangular alopecia.

    Science.gov (United States)

    Campos, Jullyene Gomes de; Oliveira, Cláudia Marina Puga Barbosa; Romero, Sandra Adolfina Reyes; Klein, Ana Paula; Akel, Patricia Bandeira de Melo; Pinto, Giselle Martins

    2015-01-01

    Temporal triangular alopecia, also referred as congenital triangular alopecia, is an uncommon dermatosis of unknown etiology. It is characterized by a non-scarring, circumscribed alopecia often located unilaterally in the frontotemporal region. It usually emerges at ages 2-9 years. Alopecia areata is the main differential diagnosis, especially in atypical cases. Dermoscopy is a noninvasive procedure that helps distinguish temporal triangular alopecia from aloepecia areata. Such procedure prevents invasive diagnostic methods as well as ineffective treatments.

  11. Analytical solution to problems of hydraulic jump in horizontal triangular channels

    Directory of Open Access Journals (Sweden)

    I.M.H. Rashwan

    2013-09-01

    Full Text Available A hydraulic jump is formed in a channel whenever supercritical flow changes to subcritical flow in a short distance. It can be used in triangular ditch irrigation to raise the downstream water surface. The basic elements and characteristics of the hydraulic jump are provided to aid designers in selecting more practical basins. In the present study, the slope side, discharge and the energy loss in hydraulic jump in horizontal triangular section are known whereas one has to obtain the sequent depths. The specific force and specific energy equations in a horizontal triangular open channel are made dimensionless, writing it for the sequent depths as a function of discharge and head loss. The proposed modes for hydraulic jump elements are of high accuracy and applicable to a wide range of discharge intensity values and initial conditions without any limitations for the assumptions under consideration.

  12. A comparison of fill factor and recombination losses in amorphous silicon solar cells on ZnO and SnO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Alkaya, A.; Canbolat, H. [Department of Electrical-Electronics Engineering, University of Mersin, Ciftlikkoy Campus, 33343 Mersin (Turkey); Kaplan, R. [Department of Secondary Science and Mathematics Education, University of Mersin, Yenisehir Campus, 33169 Mersin (Turkey); Hegedus, S.S. [Institute of Energy Conversion, University of Delaware, Newark, DE 19716 (United States)

    2009-06-15

    Effects of ZnO and SnO{sub 2} TCO (Transparent Conductive Oxide) substrate materials on hydrogenated amorphous silicon (a-Si:H) p-i-n solar cell performances and recombination kinetics have been investigated. DC and Frequency-resolved photocurrent measurements in a-Si:H p-i-n solar cells of 6 have been carried out experimentally. In particular, the I-V characteristics in the dark and light, the quantum efficiency spectra, the intensity-, bias voltage- and frequency-dependence of photocurrent were obtained. Fill factor (FF) values were determined from I-V characteristics for both types of substrate cells under various illumination levels. The exponent v in the power-law relationship, I{sub ph} {alpha} G{sup v}, between generating flux density and photocurrent were determined at different bias voltages (DC) and modulation frequencies. High values of V{sub oc} (open-circuit voltage), FF, and DC exponent v for the a-Si:H p-i-n solar cell with SnO{sub 2} were obtained, but the integrated QE (quantum efficiency), the modulated exponent v were found to be low compared to cells prepared on ZnO substrates. Our results show that these parameters are sensitive to the ZnO and SnO{sub 2} substrate materials which act as a window layer allowing most of the incident light to pass into the i-layer of p-i-n cells. (author)

  13. Electrostatically Driven Large Aperture Micro-Mirror Actuator Assemblies for High Fill-Factor, Agile Optical Phase Arrays

    Science.gov (United States)

    2015-06-18

    inverted pyramid. A reduction in the etch time, to ensure the backside of the wafer is not penetrated, would resemble an 12 inverted pyramid with...Brothers and Colleagues, Jacques (left) and Pierre (right) Curie, discoverers of the piezoelectric effect [86] cane sugar , quartz, and Rochelle salt

  14. Triangular metal wedges for subwavelength plasmon-polariton guiding at telecom wavelengths

    DEFF Research Database (Denmark)

    Boltasseva, Alexandra; Volkov, V.S.; Nielsen, Rasmus Bundgaard

    2008-01-01

    We report on subwavelength plasmon-polariton guiding by triangular metal wedges at telecom wavelengths. A high-quality fabrication procedure for making gold wedge waveguides, which is also mass- production compatible offering large-scale parallel fabrication of plasmonic components, is developed...

  15. Stability of Triangular Equilibrium Points in the Photogravitational ...

    African Journals Online (AJOL)

    This study investigates the motion of an infinitesimal mass around the triangular equilibrium points L4,5 in the elliptic restricted three-body problem when the primaries are intense emitters of radiation with further consideration that the bigger is an oblate spheroid. It is found that the motion around the triangular points is ...

  16. On linear waveguides of square and triangular lattice strips: an ...

    Indian Academy of Sciences (India)

    Basant Lal Sharma

    An analysis of the linear waves in infinitely-long square and triangular lattice strips of identical particles with .... with a small snapshot of the mode shape across the waveguide 'cross-section' and (d) a 'tube' of square and triangular lattice waveguides ...... [58] Mason J C and Handscomb D C 2003 Chebyshev polyno- mials.

  17. Wrist stability after experimental traumatic triangular fibrocartilage complex lesions

    DEFF Research Database (Denmark)

    Munk, Bo; Jensen, Steen Lund; Olsen, Bo Sanderhoff

    2005-01-01

    The aim of this study was to evaluate changes in stability of the wrist after experimental traumatic triangular fibrocartilage complex lesions.......The aim of this study was to evaluate changes in stability of the wrist after experimental traumatic triangular fibrocartilage complex lesions....

  18. Triangular Arbitrage as an Interaction in Foreign Exchange Markets

    Science.gov (United States)

    Aiba, Yukihiro; Hatano, Naomichi

    Analyzing correlation in financial time series is a topic of considerable interest [1]-[17]. In the foreign exchange market, a correlation among the exchange rates can be generated by a triangular arbitrage transaction. The purpose of this article is to review our recent study [18]-[23] on modeling the interaction generated by the triangular arbitrage.

  19. Limits of commutative triangular systems on locally compact groups

    Indian Academy of Sciences (India)

    Keywords. Embeddable measures; triangular systems of measures; infinitesimally divisible measures; totally disconnected groups; real algebraic groups. 1. Introduction. Commutative triangular systems of probability measures on locally compact groups have been studied extensively and recently the embedding of the limit ...

  20. Triangular model integrating clinical teaching and assessment.

    Science.gov (United States)

    Abdelaziz, Adel; Koshak, Emad

    2014-01-01

    Structuring clinical teaching is a challenge facing medical education curriculum designers. A variety of instructional methods on different domains of learning are indicated to accommodate different learning styles. Conventional methods of clinical teaching, like training in ambulatory care settings, are prone to the factor of coincidence in having varieties of patient presentations. Accordingly, alternative methods of instruction are indicated to compensate for the deficiencies of these conventional methods. This paper presents an initiative that can be used to design a checklist as a blueprint to guide appropriate selection and implementation of teaching/learning and assessment methods in each of the educational courses and modules based on educational objectives. Three categories of instructional methods were identified, and within each a variety of methods were included. These categories are classroom-type settings, health services-based settings, and community service-based settings. Such categories have framed our triangular model of clinical teaching and assessment.

  1. Magnetic phase diagrams of classical triangular and kagome antiferromagnets

    Energy Technology Data Exchange (ETDEWEB)

    Gvozdikova, M V [Department of Physics, Kharkov National University, 61077 Kharkov (Ukraine); Melchy, P-E; Zhitomirsky, M E, E-mail: mike.zhitomirsky@cea.fr [Service de Physique Statistique, Magnetisme et Supraconductivite, UMR-E9001 CEA-INAC/UJF, 17 rue des Martyrs, 38054 Grenoble (France)

    2011-04-27

    We investigate the effect of geometrical frustration on the H-T phase diagrams of the classical Heisenberg antiferromagnets on triangular and kagome lattices. The phase diagrams for the two models are obtained from large-scale Monte Carlo simulations. For the kagome antiferromagnet, thermal fluctuations are unable to lift degeneracy completely and stabilize translationally disordered multipolar phases. We find a substantial difference in the temperature scales of the order by disorder effect related to different degeneracy of the low- and the high-field classical ground states in the kagome antiferromagnet. In the low-field regime, the Kosterlitz-Thouless transition into a spin-nematic phase is produced by unbinding of half-quantum vortices.

  2. A simple method for understanding the triangular growth patterns of transition metal dichalcogenide sheets

    Directory of Open Access Journals (Sweden)

    Siya Zhu

    2015-10-01

    Full Text Available Triangular nanoflake growth patterns have been commonly observed in synthesis of transition metal dichalcogenide sheets and their hybrid structures. Triangular nanoflakes not only show exceptional properties, but also can serve as building blocks for two or three dimensional structures. In this study, taking the MoS2 system as a test case, we propose a Matrix method to understand the mechanism of such unique growth pattern. Nanoflakes with different edge types are mathematically described with configuration matrices, and the total formation energy is calculated as the sum of the edge formation energies and the chemical potentials of sulfur and molybdenum. Based on energetics, we find that three triangular patterns with the different edge configurations are energetically more favorable in different ranges of the chemical potential of sulfur, which are in good agreement with experimental observations. Our algorithm has high efficiency and can deal with nanoflakes in microns which are beyond the ability of ab-initio method. This study not only elucidates the mechanism of triangular nanoflake growth patterns in experiment, but also provides a clue to control the geometric configurations in synthesis.

  3. A New Triangular Flat Shell Element With Drilling Rotations

    DEFF Research Database (Denmark)

    Damkilde, Lars

    2008-01-01

    A new flat triangular shell element has been developed based on a newly developed triangular plate bending element by the author and a new triangular membrane element with drilling degrees of freedom. The advantage of the drilling degree of freedom is that no special precautions have to be made...... in connecting with assembly of elements. Due to the drilling rotations all nodal degrees of freedom have stiffness, and therefore no artificial suppression of degrees of freedom are needed for flat or almost flat parts of the shell structure....

  4. RAPID COMMUNICATION: Conducting triangular chambers for EMC measurements

    Science.gov (United States)

    Huang, Yi

    1999-03-01

    Conducting rectangular chambers have been used extensively for electromagnetic compatibility (EMC) shielding and measurement applications. In this communication, conducting triangular chambers are investigated as an alternative structure for rectangular EMC reverberation chambers, which are becoming an increasingly important and powerful tool for both radiated immunity and emission tests. A prime consideration of designing such a system is the total possible number of modes inside the chamber. A new approach is introduced to obtain this parameter for three different triangular chambers. The initial study has demonstrated that triangular chambers may offer better performance in some cases than their rectangular counterparts.

  5. On certain topological indices of boron triangular nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Aslam, Adnan [Univ. of Engineering and Technology, Lahore (Pakistan). Dept. of Natural Sciences and Humanities; Ahmad, Safyan [GC Univ. Lahore (Pakistan). Abdus Salam School of Mathematical Sciences; Gao, Wei [Yunnan Normal Univ., Kunming (China). School of Information Science and Technology

    2017-11-01

    The topological index gives information about the whole structure of a chemical graph, especially degree-based topological indices that are very useful. Boron triangular nanotubes are now replacing usual carbon nanotubes due to their excellent properties. We have computed general Randic (R{sub a}), first Zagreb (M{sub 1}) and second Zagreb (M{sub 2}), atom-bond connectivity (ABC), and geometric-arithmetic (GA) indices of boron triangular nanotubes. Also, we have computed the fourth version of atom-bond connectivity (ABC{sub 4}) and the fifth version of geometric-arithmetic (GA{sub 5}) indices of boron triangular nanotubes.

  6. Logical, algebraic, analytic and probabilistic aspects of triangular norms

    CERN Document Server

    Klement, Erich Peter

    2005-01-01

    This volume gives a state of the art of triangular norms which can be used for the generalization of several mathematical concepts, such as conjunction, metric, measure, etc. 16 chapters written by leading experts provide a state of the art overview of theory and applications of triangular norms and related operators in fuzzy logic, measure theory, probability theory, and probabilistic metric spaces.Key Features:- Complete state of the art of the importance of triangular norms in various mathematical fields- 16 self-contained chapters with extensive bibliographies cover both the theoretical ba

  7. Cervantes vs Cinthio: a funny triangular game

    Directory of Open Access Journals (Sweden)

    Aldo Ruffinatto

    2012-12-01

    Full Text Available When talking about the role of descriptive parts in fiction in Quijote (II.18, Cervantes no doubt had in mind Giraldi Cinthio and his theoretical statements; the Spanish author was insinuating irony in an apparently serious context. It is also impossible to doubt that, when interpolating in his Persiles (III.6 the first part of the tale of the Polish Ortel Banedre, Cervantes is once more alluding to the humanist, namely to one of his Hecatommithi, which develops parallel narrative sequences (the sixth of the sixth Deca. After examining the triangular game created by 1 main narrator 2 secondary narrator 3 listener of the narration in the two texts, we can discover the deep reasons which generate visible effects on the superficial structure of meta-diegetic tale. Cinthio’s closed triangle which leads the listener towards the main narrator (who, this way, guarantees the reliability of the secondary narrator determines and certifies the exemplary nature of the tale of frogiveness in the version of the Italian writer. Cervante’s open triangle, on the contrary, which does not put in touch the listener with the main narrator (and, in this way, leaves the responsability of the related facts on the shoulders of the secondary narrator only gives credit to and generates the deep changes that characterize version of the same tale.

  8. Final critical habitat for Triangular Kidneyshell (Ptychobranchus greenii)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This Polygon shapefile of critical habitat for the Triangular Kidneyshell (Ptychobranchus greenii) based on the description provided in the Federal Register.

  9. Spintronic properties of zigzag-edged triangular graphene flakes

    OpenAIRE

    Şahin, Hasan; Senger, Ramazan Tuğrul; Çıracı, Salim

    2010-01-01

    We investigate quantum transport properties of triangular graphene flakes with zigzag edges by using first principles calculations. Triangular graphene flakes have large magnetic moments which vary with the number of hydrogen atoms terminating its edge atoms and scale with its size. Electronic transmission and current-voltage characteristics of these flakes, when contacted with metallic electrodes, reveal spin valve and remarkable rectification features. The transition from ferromagnetic to a...

  10. On the Eigenvalues and Eigenvectors of Block Triangular Preconditioned Block Matrices

    KAUST Repository

    Pestana, Jennifer

    2014-01-01

    Block lower triangular matrices and block upper triangular matrices are popular preconditioners for 2×2 block matrices. In this note we show that a block lower triangular preconditioner gives the same spectrum as a block upper triangular preconditioner and that the eigenvectors of the two preconditioned matrices are related. © 2014 Society for Industrial and Applied Mathematics.

  11. Low-cost Triangular Lattice Towers for Small Wind Turbines

    Science.gov (United States)

    Adhikari, Ram Chandra

    This thesis focuses on the study of low-cost steel and bamboo triangular lattice towers for small wind turbines. The core objective is to determine the material properties of bamboo and assess the feasibility of bamboo towers. Using the experimentally determined buckling resistance, elastic modulus, and Poisson's ratio, a 12 m high triangular lattice tower for a 500W wind turbine has been modeled as a tripod to formulate the analytical solutions for the stresses and tower deflections, which enables design of the tower based on buckling strength of tower legs. The tripod formulation combines the imposed loads, the base distance between the legs and tower height, and cross-sectional dimensions of the tower legs. The tripod model was used as a reference for the initial design of the bamboo tower and extended to finite element analysis. A 12 m high steel lattice tower was also designed for the same turbine to serve as a comparison to the bamboo tower. The primary result of this work indicates that bamboo is a valid structural material. The commercial software package ANSYS APDL was used to carry out the tower analysis, evaluate the validity of the tripod model, and extend the analysis for the tower design. For this purpose, a 12 m high steel lattice tower for a 500 W wind turbine was examined. Comparison of finite element analysis and analytical solution has shown that tripod model can be accurately used in the design of lattice towers. The tower designs were based on the loads and safety requirements of international standard for small wind turbine safety, IEC 61400-2. For connecting the bamboo sections in the lattice tower, a steel-bamboo adhesive joint combined with conventional lashing has been proposed. Also, considering the low durability of bamboo, periodic replacement of tower members has been proposed. The result of this study has established that bamboo could be used to construct cost-effective and lightweight lattice towers for wind turbines of 500 Watt

  12. Laser cutting of triangular geometry into 2024 aluminum alloy: Influence of triangle size on thermal stress field

    Energy Technology Data Exchange (ETDEWEB)

    Yilbas, Bekir Sami; Akhtar, Syed Sohail [King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Keles, Omer; Boran, Kurtulus [Gazi University, Ankara (Turkmenistan)

    2015-08-15

    Laser cutting of a triangular geometry into aluminum 2024 alloy is carried out. Thermal stress field in the cutting section is predicted using the finite element code ABAQUS. Surface temperature predictions are validated through the thermocouple data. Morphological changes in the cut section are examined incorporating optical and electron scanning microscopes. The effects of the size of the triangular geometry on thermal stress field are also examined. It is found that surface temperature predictions agree well with thermocouple data. von Mises stress remains high in the region close to the corners of the triangular geometry, which is more pronounced for the small size triangle. This behavior is associated with the occurrence of the high cooling rates in this region. Laser cut edges are free from large scale sideways burning and large size burr attachments. However, some locally scattered dross attachments are observed at the kerf exit.

  13. Carbon Substitution on N24 Cages: Crossover between Triangular and Hexagonal Structures

    Directory of Open Access Journals (Sweden)

    Carrie Sanders

    2013-01-01

    Full Text Available Complex forms of nitrogen are of interest for their potential as high-energy materials, but many all-nitrogen systems lack the stability for practical high-energy applications. Inclusion of carbon atoms in an otherwise all-nitrogen structure can increase stability. Nitrogen cages are known for energetically preferring cylindrical structures with triangular endcaps, but carbon cages prefer the pentagon-hexagon structure of the fullerenes. Previous calculations on N22C2 have shown that carbon inclusion narrows the gap between triangular and fullerene-like structures. In the current study, three isomers of N24 are used as frameworks for carbon substitution. Theoretical calculations are carried out on isomers of N20C4, N18C6, and N16C8, with the goal of determining what level of carbon substitution causes the carbon fullerene-like structures to become energetically preferred.

  14. Tailoring graphene magnetism by zigzag triangular holes: A first-principles thermodynamics study

    Directory of Open Access Journals (Sweden)

    Muhammad Ejaz Khan

    2016-03-01

    Full Text Available We discuss the thermodynamic stability and magnetic property of zigzag triangular holes (ZTHs in graphene based on the results of first-principles density functional theory calculations. We find that ZTHs with hydrogen-passivated edges in mixed sp2/sp3 configurations (z211 could be readily available at experimental thermodynamic conditions, but ZTHs with 100% sp2 hydrogen-passivation (z1 could be limitedly available at high temperature and ultra-high vacuum conditions. Graphene magnetization near the ZTHs strongly depends on the type and the size of the triangles. While metallic z1 ZTHs exhibit characteristic edge magnetism due to the same-sublattice engineering, semiconducting z211 ZTHs do show characteristic corner magnetism when the size is small <2 nm. Our findings could be useful for experimentally tailoring metal-free carbon magnetism by simply fabricating triangular holes in graphene.

  15. Synthesis of gold hexagonal bipyramids directed by planar-twinned silver triangular nanoprisms.

    Science.gov (United States)

    Personick, Michelle L; Langille, Mark R; Wu, Jinsong; Mirkin, Chad A

    2013-03-13

    The direct growth of planar-twinned Au nanoparticles (NPs) in high yield remains a challenge in shape-controlled NP synthesis largely because suitable planar-twinned seeds for Au NP growth have not been identified to date. Herein we describe the use of planar-twinned Ag triangular nanoprisms as a means to dictate Au NP twin structure. In a one-pot process, the Ag triangular nanoprisms first undergo oxidative Au replacement, forming Ag-Au alloy nanoframes and concomitantly releasing Ag(+) into solution, which then directs subsequent Au NP growth through an underpotential deposition process. The planar-twinned structure of the initial Ag nanoprism is maintained throughout particle growth. Using this method, we have successfully synthesized Au hexagonal bipyramids in high yield for the first time.

  16. Triangular and Fibonacci number patterns driven by stress on core/shell microstructures.

    Science.gov (United States)

    Li, Chaorong; Zhang, Xiaona; Cao, Zexian

    2005-08-05

    Fibonacci number patterns and triangular patterns with intrinsic defects occur frequently on nonplanar surfaces in nature, particularly in plants. By controlling the geometry and the stress upon cooling, these patterns can be reproduced on the surface of microstructures about 10 micrometers in diameter. Spherules of the Ag core/SiOx shell structure, possessing markedly uniform size and shape, self-assembled into the Fibonacci number patterns (5 by 8 and 13 by 21) or the triangular pattern, depending on the geometry of the primary supporting surface. Under proper geometrical constraints, the patterns developed through self-assembly in order to minimize the total strain energy. This demonstrates that highly ordered microstructures can be prepared simultaneously across large areas by stress engineering.

  17. Evidence for Triangular D_3h Symmetry in 12C

    CERN Document Server

    Marin-Lambarri, D J; Freer, M; Gai, M; Kokalova, Tz; Parker, D J; Wheldon, C

    2014-01-01

    We report a measurement of a new high spin Jp = 5- state at 22.4(0.2) MeV in 12C which fits very well to the predicted (ground state) rotational band of an oblate equilateral triangular spinning top with a D_3h symmetry characterized by the sequence 0+, 2+, 3-, 4+/-, 5- with almost degenerate 4+ and 4- (parity doublet) states. Such a D_3h symmetry was observed in triatomic molecules and it is observed here for the first time in nuclear physics. We discuss a classification of other rotation-vibration bands in 12C such as the (0+) Hoyle band and the (1-) bending mode band and suggest measurements in search of the predicted ("missing") states that may shed new light on clustering in 12C and light nuclei. In particular the observation (or non-observation) of the predicted ("missing") states in the Hoyle band will allow us to conclude the geometrical arrangement of the three alpha-particle composing the Hoyle state at 7.654 MeV in 12C.

  18. Elementary dispersion analysis of some mimetic discretizations on triangular C-grids

    Energy Technology Data Exchange (ETDEWEB)

    Korn, P., E-mail: peter.korn@mpimet.mpg.de [Max Planck Institute for Meteorology, Hamburg (Germany); Danilov, S. [Alfred Wegener Institute for Polar and Marine Research, Bremerhaven (Germany); A.M. Obukhov Institute of Atmospheric Physics, Moscow (Russian Federation)

    2017-02-01

    Spurious modes supported by triangular C-grids limit their application for modeling large-scale atmospheric and oceanic flows. Their behavior can be modified within a mimetic approach that generalizes the scalar product underlying the triangular C-grid discretization. The mimetic approach provides a discrete continuity equation which operates on an averaged combination of normal edge velocities instead of normal edge velocities proper. An elementary analysis of the wave dispersion of the new discretization for Poincaré, Rossby and Kelvin waves shows that, although spurious Poincaré modes are preserved, their frequency tends to zero in the limit of small wavenumbers, which removes the divergence noise in this limit. However, the frequencies of spurious and physical modes become close on shorter scales indicating that spurious modes can be excited unless high-frequency short-scale motions are effectively filtered in numerical codes. We argue that filtering by viscous dissipation is more efficient in the mimetic approach than in the standard C-grid discretization. Lumping of mass matrices appearing with the velocity time derivative in the mimetic discretization only slightly reduces the accuracy of the wave dispersion and can be used in practice. Thus, the mimetic approach cures some difficulties of the traditional triangular C-grid discretization but may still need appropriately tuned viscosity to filter small scales and high frequencies in solutions of full primitive equations when these are excited by nonlinear dynamics.

  19. Boron Triangular Kagome Lattice with Half-Metallic Ferromagnetism.

    Science.gov (United States)

    Kim, Sunghyun; Han, W H; Lee, In-Ho; Chang, K J

    2017-08-04

    Based on the first-principles evolutionary materials design, we report a stable boron Kagome lattice composed of triangles in triangles on a two-dimensional sheet. The Kagome lattice can be synthesized on a silver substrate, with selecting Mg atoms as guest atoms. While the isolated Kagome lattice is slightly twisted without strain, it turns into an ideal triangular Kagome lattice under tensile strain. In the triangular Kagome lattice, we find the exotic electronic properties, such as topologically non-trivial flat band near the Fermi energy and half-metallic ferromagnetism, and predict the quantum anomalous Hall effect in the presence of spin-orbit coupling.

  20. Quality improvement of surface triangular mesh using a modified Laplacian smoothing approach avoiding intersection.

    Directory of Open Access Journals (Sweden)

    Tiantian Liu

    Full Text Available We present a systematic procedure to improve the qualities of triangular molecular surface meshes and at the same time preserve the manifoldness. The procedure utilizes an algorithm to remove redundant points having three or four valences and another algorithm to smooth the mesh using a modified version of Laplacian method without causing intersecting triangles. This approach can be effectively applied to any manifold surface meshes with arbitrary complex geometry. In this paper, the tested meshes are biomolecular surface meshes exhibiting typically highly irregular geometry. The results show that the qualities of the surface meshes are greatly improved and the manifoldness of the surface meshes are preserved. Compared with the original meshes, these improved molecular surface meshes can be directly applied to boundary element simulations and generation of body-fitted volume meshes using Tetgen. The procedure has been incorporated into our triangular molecular surface mesh generator, TMSmesh 2.0. It can be also used as a standalone program and works together with any other surface triangular mesh generator to obtain qualified manifold mesh. The package is downloadable at https://doi.org/10.6084/m9.figshare.5346169.v1 and can be run online at http://www.xyzgate.com.

  1. Flat plate film cooling at the coolant supply into triangular and cylindrical craters

    Directory of Open Access Journals (Sweden)

    Khalatov Artem A.

    2017-01-01

    Full Text Available The results are given of the film cooling numerical simulation of three different schemes including single-array of the traditional round inclined holes, as well as inclined holes arranged in the cylindrical or triangular dimples (craters. The results of simulation showed that at the medium and high values of the blowing ratio (m > 1.0 the scheme with coolant supply into triangular craters improves the adiabatic film cooling efficiency by 1.5…2.7 times compared to the traditional array of inclined holes, or by 1.3…1.8 times compared to the scheme with coolant supply into cylindrical craters. The greater film cooling efficiency with the coolant supply into triangular craters is explained by decrease in the intensity of secondary vortex structures (“kidney” vortex. This is due to the partial destruction and transformation of the coolant jets structure interacting with front wall of the crater. Simultaneously, the film cooling uniformity is increased in the span-wise direction.

  2. Investigating Triangular Numbers with greatest integer function, Sequences and Double Factorial

    Directory of Open Access Journals (Sweden)

    Tilahun A Muche

    2016-11-01

    Full Text Available The Triangular number denoted by is defined as the sum of the first consecutive positive integers. A positive integer is a Triangular Number if and only if [1]. We stated and proved a sequence of positive integers is consecutive triangular numbers if and only if √ − √ =1 and √ . We consider a ceiling function ⌈ ⌉ to state and prove a necessary and sufficient condition for a number ⌈ ⌉ ⌈ ⌉ to be a triangular number for each . A formula to find and of any two consecutive triangular numbers and a double factorial is introduced to find products of triangular numbers.

  3. Molluscicidal Effects of Talinum triangulare on Bulinus truncatus ...

    African Journals Online (AJOL)

    On coming in contact with the test medium, the snails reacted by speedily crawling out of the containers. Exposure of snails to Talinum triangulare concentrations of less than 300ppm showed only ovicidal activity while varying numbers of those exposed to 300ppm died as the exposure time increased. The control group ...

  4. Inheritance of pigmentation patterns in Talinum triangulare (Jacq ...

    African Journals Online (AJOL)

    The segregation pattern for stigma colour indicates complete dominance of deep pink over light pink colour. The same gene which is in the homozygous state conditions deep pink pigmentations on the leaf base and panicle junction in the two variants of T. triangulare investigated. Keywords: Intraspecific, Petal Colour, ...

  5. Stability of Triangular Equilibrium Points in the Photogravitational ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... We have examined the effects of oblateness up to 4 of the less massive primary and gravitational potential from a circum-binary belt on the linear stability of triangular equilibrium points in the circular restricted three-body problem, when the more massive primary emits electromagnetic radiation impinging ...

  6. Stability derivatives of triangular wings at supersonic speeds

    Science.gov (United States)

    Ribner, Herbert S; Malvestuto, Frank S , Jr

    1948-01-01

    The analysis of the stability derivatives of low-aspect-ratio triangular wings at subsonic and supersonic speeds, given in NACA TN no. 1423, is extended to apply to triangular wings having large vertex angles and traveling at supersonic speeds. The lift, rolling moment due to sideslip, and damping in roll and pitch for this more general case have been treated elsewhere on the basis of the theory of small disturbances. The surface potentials for angle of attack and rolling taken therefrom are used to obtain the several side-force and yawing-moment derivatives that depend on leading-edge suction, and a tentative value for the rolling moment due to yawing. The lift and moment due to downward acceleration are obtained on the basis of an unpublished unsteady-flow solution. All the known stability derivatives of the triangular wing at supersonic speeds, regardless of source, are summarized for convenience and presented with respect to both body axes and stability axes. The results are limited to Mach numbers for which the triangular wing is contained within the Mach cone for its vertex. The spanwise variation of Mach number in the case of yawing is neglected, although the effect must be of importance.

  7. Dominance on Strict Triangular Norms and Mulholland Inequality

    Czech Academy of Sciences Publication Activity Database

    Petrík, Milan

    Available online 12 June 2017 (2018) ISSN 0165-0114 R&D Projects: GA ČR GJ15-07724Y Institutional support: RVO:67985807 Keywords : dominance relation * Mulholland inequality * strict triangular norm * transitivity Subject RIV: BA - General Mathematics Impact factor: 2.718, year: 2016

  8. Triangular Numbers, Gaussian Integers, and KenKen

    Science.gov (United States)

    Watkins, John J.

    2012-01-01

    Latin squares form the basis for the recreational puzzles sudoku and KenKen. In this article we show how useful several ideas from number theory are in solving a KenKen puzzle. For example, the simple notion of triangular number is surprisingly effective. We also introduce a variation of KenKen that uses the Gaussian integers in order to…

  9. The computation of linear triangular matrices in the finite element ...

    African Journals Online (AJOL)

    An algorithm is developed for generating the system matrices for the Finite Element Method of solving some classes of second order partial differential equations problems using the linear triangular elements. This algorithm reduces the complexity normally associated with the finite element approximation and makes the ...

  10. Behaviour of Lagrangian triangular mixed fluid finite elements

    Indian Academy of Sciences (India)

    The behaviour of mixed fluid finite elements, formulated based on the Lagrangian frame of reference, is investigated to understand the effects of locking due to incompressibility and irrotational constraints. For this purpose, both linear and quadratic mixed triangular fluid elements are formulated. It is found that there exists a ...

  11. Fissioned Triangular Schemes Via the Cross-Ratio

    NARCIS (Netherlands)

    van Dam, E.R.; de Caen, D.

    1999-01-01

    A construction of association schemes is presented; these are fission schemes of the triangular schemes T(n) where n=q + 1with q any prime power. The key observation is quite elementary, being that the natural action of PGL(2,q) on the 2-element subsets of the projective line PG(1,q) is generously

  12. Codes related to line graphs of triangular graphs and permutation ...

    African Journals Online (AJOL)

    For any prime p, we consider p-ary linear codes obtained from the row span of incidence matrices of line graphs of triangular graphs and adjacency matrices of their line graphs. We determine parameters of the codes, their automorphism groups and exhibit permutation decoding sets (PD-sets) for partial permutation ...

  13. On generalized absolute summability factors for a triangular matrix

    Energy Technology Data Exchange (ETDEWEB)

    Savas, Ekrem [Department of Mathematics Istanbul Ticaret University Uskudar, Istanbul (Turkey)], E-mail: ekremsavas@yahoo.com

    2009-04-15

    In this paper, we establish a summability factor theorem for summability |A, {delta} |{sub k} as defined in . This paper is an extension of the main result of Savas and Rhoades [Savas E, Rhoades B. On absolute summability factors for a triangular matrix. Int J Diff Equat 2006;1:155-63].

  14. Global properties of the triangular systems in the singular case

    Science.gov (United States)

    Korobov, V. I.; Pavlichkov, S. S.

    2008-06-01

    We introduce a new class of the triangular (multi-input and multi-output) control systems, of O.D.E., which are not feedback linearizable, and investigate its global behavior. The triangular form introduced is a generalization of the classes of triangular systems, considered before. For our class, we solve the problem of global robust controllability. Combining our main result with that of [F.H. Clarke, Yu.S. Ledyaev, E.D. Sontag, A.I. Subbotin, Asymptotic controllability implies feedback stabilization, IEEE Trans. Automat. Control 42 (1997) 1394-1407], we obtain a corollary on the global discontinuous sampled stabilization (an example showing that global smooth stabilization can be irrelevant to the singular case is considered). To prove our main result, we apply a certain "back-stepping" algorithm and combine the technique proposed in [V.I. Korobov, S.S. Pavlichkov, W.H. Schmidt, Global robust controllability of the triangular integro-differential Volterra systems, J. Math. Anal. Appl. 309 (2005) 743-760] with solving a specific problem of global "practical stabilization" by means of a discontinuous, time-varying feedback law.

  15. Lattice Boltzmann scheme for diffusion on triangular grids

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2003-01-01

    In this paper we present a Lattice Boltzmann scheme for diffusion on it unstructured triangular grids. In this formulation of a LB for irregular grids there is no need for interpolation, which is required in other LB schemes on irregular grids. At the end of the propagation step the lattice gas

  16. MeshLab: 3D triangular meshes processing and editing

    Science.gov (United States)

    Cignoni, P.; Callieri, M.; Corsini, M.; Dellepiane, M.; Ganovelli, F.; Ranzuglia, G.

    2017-09-01

    MeshLab processes and edits 3D triangular meshes. It includes tools for editing, cleaning, healing, inspecting, rendering, texturing and converting meshes, and offers features for processing raw data produced by 3D digitization tools and devices and for preparing models for 3D printing.

  17. Diffusion on unstructured triangular grids using Lattice Boltzmann

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2004-01-01

    In this paper, we present a Lattice Boltzmann scheme for diffusion on unstructured triangular grids. In this formulation there is no need for interpolation, as is required in other LB schemes on irregular grids. At the end of the propagation step, the lattice gas particles arrive exactly at

  18. On linear waveguides of square and triangular lattice strips: an ...

    Indian Academy of Sciences (India)

    An analysis of the linear waves in infinitely-long square and triangular lattice strips of identical particles with nearest neighbour interactions for all combinations of fixed and free boundary conditions, as well as the periodic boundary, is presented. Expressions for the dispersion relations and the associated normal modes in ...

  19. Page 1 Centrifugal distortion constants - - 115 triangular form ...

    Indian Academy of Sciences (India)

    Centrifugal distortion constants - - 115 triangular form (Ananthakrishnan et al 1972, 1973, 1976). In this context, setting. C equal to unit matrix is identical with the L matrix approximation technique developed by Muller (Alix et al 1975) and should hold good for nonhydride mole- cules as is implied in the observations of Strey ...

  20. An algorithm for finding block-triangular forms

    NARCIS (Netherlands)

    Dietzenbacher, Erik

    In this paper, an algorithm is constructed for finding the block triangular form of a nonnegative matrix. The algorithm is based on the zero elements of the left and right Perron vectors of the matrix and, subsequently, certain submatrices. The construction of the algorithm Is motivated by the

  1. Behaviour of Lagrangian triangular mixed fluid finite elements

    Indian Academy of Sciences (India)

    insufficient degrees of freedom available in these elements to satisfy the twin constraints. Note that the number of constraints an element has to satisfy is proportional to the number of integration points used to numerically evaluate the stiffness matrix. However, in the case of quadratic triangular fluid elements, it was shown ...

  2. Euler y la Conjetura de Fermat sobre Números Triangulares

    Directory of Open Access Journals (Sweden)

    José Manuel Sánchez Muñoz

    2011-04-01

    Full Text Available Este artículo describe la historia de como Euler demostró la existencia de infinitos números triangulares bicuadráticos, desde su correspondencia con su amigo Christian Goldbach hasta la publicación de sus resultados en la Academia de San Petesburgo.

  3. High-field magnetization and ESR in the triangular-lattice antiferromagnets Ba{sub 3}MnSb{sub 2}O{sub 9} and Ba{sub 3}TNb{sub 2}O{sub 9} (T=Ni, Co)

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Y.C. [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Ouyang, Z.W., E-mail: zwouyang@mail.hust.edu.cn [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Ruan, M.Y.; Guo, Y.M.; Cheng, J.J. [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Tian, Z.M. [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Xia, Z.C. [Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074 (China); Rao, G.H. [School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin 541004 (China)

    2015-11-01

    We report high-field magnetization and electronic spin resonance (ESR) study on the triangular-lattice antiferromagnets Ba{sub 3}MnSb{sub 2}O{sub 9} and Ba{sub 3}TNb{sub 2}O{sub 9} (T=Ni, Co). The antiferromagnetic (AFM) ordering at T{sub N} is clearly characterized by the temperature dependent ESR spectra. In Ba{sub 3}CoNb{sub 2}O{sub 9}, the complicated ESR peaks are observed above T{sub N}. No obvious frequency–field relationship could be deduced. In Ba{sub 3}NiNb{sub 2}O{sub 9}, the AFM resonance with easy-plane anisotropy is observed, and accordingly, the magnetic exchange interactions are estimated. For Ba{sub 3}MnSb{sub 2}O{sub 9}, the remarkable finding is that single resonance peak at paramagnetic state splits into double peaks below the ordering temperature. Possible interpretations for these unusual AFM resonance modes have been proposed. - Highlights: • In Ba{sub 3}NiNb{sub 2}O{sub 9}, anisotropy is observed, exchange interactions are estimated. • In Ba{sub 3}MnSb{sub 2}O{sub 9}, single resonance peaksplits into double peaks below T{sub N}. • Complicated ESR spectra have been observed in Ba{sub 3}CoNb{sub 2}O{sub 9} above T{sub N}.

  4. TINITALY/01: a new Triangular Irregular Network of Italy

    Directory of Open Access Journals (Sweden)

    M. T. Pareschi

    2007-06-01

    Full Text Available A new Digital Elevation Model (DEM of the natural landforms of Italy is presented. A methodology is discussed to build a DEM over wide areas where elevation data from non-homogeneous (in density and accuracy input sources are available. The input elevation data include contour lines and spot heights derived from the Italian Regional topographic maps, satellite-based global positioning system points, ground based and radar altimetry data. Owing to the great heterogeneity of the input data density, the DEM format that better preserves the original accuracy is a Triangular Irregular Network (TIN. A Delaunay-based TIN structure is improved by using the DEST algorithm that enhances input data by evaluating inferred break-lines. Accordingly to this approach, biased distributions in slopes and elevations are absent. To prevent discontinuities at the boundary between regions characterized by data with different resolution a cubic Hermite blending weight S-shaped function is adopted. The TIN of Italy consists of 1.39×109 triangles. The average triangle area ranges from 12 to about 13000 m2 accordingly to different morphologies and different sources. About 50% of the model has a local average triangle area <500 m2. The vertical accuracy of the obtained DEM is evaluated by more than 200000 sparse control points. The overall Root Mean Square Error (RMSE is less than 3.5 m. The obtained national-scale DEM constitutes an useful support to carry out accurate geomorphological and geological investigations over large areas. The problem of choosing the best step size in deriving a grid from a TIN is then discussed and a method to quantify the loss of vertical information is presented as a function of the grid step. Some examples of DEM application are outlined. Under request, an high resolution stereo image database of the whole Italian territory (derived from the presented DEM is available to browse via internet.

  5. Hierarchically triangular prism structured Co3O4: Self-supported fabrication and photocatalytic property

    Science.gov (United States)

    The formation of ammonium cobalt (II) phosphate was utilized to synthesize unprecedented 3D structures of Co3O4, triangular prisms and trunk-like structures, via a self-supported and organics-free method. The length of a triangular side of the prepared 3D triangular prisms is ~1...

  6. Logical spin-filtering in a triangular network of quantum nanorings with a Rashba spin-orbit interaction

    Science.gov (United States)

    Dehghan, E.; Sanavi Khoshnoud, D.; Naeimi, A. S.

    2018-01-01

    The spin-resolved electron transport through a triangular network of quantum nanorings is studied in the presence of Rashba spin-orbit interaction (RSOI) and a magnetic flux using quantum waveguide theory. This study illustrates that, by tuning Rashba constant, magnetic flux and incoming electron energy, the triangular network of quantum rings can act as a perfect logical spin-filtering with high efficiency. By changing in the energy of incoming electron, at a proper value of the Rashba constant and magnetic flux, a reverse in the direction of spin can take place in the triangular network of quantum nanorings. Furthermore, the triangular network of quantum nanorings can be designed as a device and shows several simultaneous spintronic properties such as spin-splitter and spin-inverter. This spin-splitting is dependent on the energy of the incoming electron. Additionally, different polarizations can be achieved in the two outgoing leads from an originally incoming spin state that simulates a Stern-Gerlach apparatus.

  7. Simultaneous travel time tomography for updating both velocity and reflector geometry in triangular/tetrahedral cell model

    Science.gov (United States)

    Bai, Chao-ying; He, Lei-yu; Li, Xing-wang; Sun, Jia-yu

    2017-12-01

    To conduct forward and simultaneous inversion in a complex geological model, including an irregular topography (or irregular reflector or velocity anomaly), we in this paper combined our previous multiphase arrival tracking method (referred as triangular shortest-path method, TSPM) in triangular (2D) or tetrahedral (3D) cell model and a linearized inversion solver (referred to as damped minimum norms and constrained least squares problem solved using the conjugate gradient method, DMNCLS-CG) to formulate a simultaneous travel time inversion method for updating both velocity and reflector geometry by using multiphase arrival times. In the triangular/tetrahedral cells, we deduced the partial derivative of velocity variation with respective to the depth change of reflector. The numerical simulation results show that the computational accuracy can be tuned to a high precision in forward modeling and the irregular velocity anomaly and reflector geometry can be accurately captured in the simultaneous inversion, because the triangular/tetrahedral cell can be easily used to stitch the irregular topography or subsurface interface.

  8. Gap Reversal at Filling Factors 3 +1 /3 and 3 +1 /5 : Towards Novel Topological Order in the Fractional Quantum Hall Regime

    Science.gov (United States)

    Kleinbaum, Ethan; Kumar, Ashwani; Pfeiffer, L. N.; West, K. W.; Csáthy, G. A.

    2015-02-01

    In the region of the second Landau level several theories predict fractional quantum Hall states with novel topological order. We report the opening of an energy gap at the filling factor ν =3 +1 /3 , firmly establishing the ground state as a fractional quantum Hall state. This and other odd-denominator states unexpectedly break particle-hole symmetry. Specifically, we find that the relative magnitudes of the energy gaps of the ν =3 +1 /3 and 3 +1 /5 states from the upper spin branch are reversed when compared to the ν =2 +1 /3 and 2 +1 /5 counterpart states in the lower spin branch. Our findings raise the possibility that at least one of the former states is of an unusual topological order.

  9. Spin-electric Berry phase shift in triangular molecular magnets

    Science.gov (United States)

    Azimi Mousolou, Vahid; Canali, C. M.; Sjöqvist, Erik

    2016-12-01

    We propose a Berry phase effect on the chiral degrees of freedom of a triangular magnetic molecule. The phase is induced by adiabatically varying an external electric field in the plane of the molecule via a spin-electric coupling mechanism present in these frustrated magnetic molecules. The Berry phase effect depends on spin-orbit interaction splitting and on the electric dipole moment. By varying the amplitude of the applied electric field, the Berry phase difference between the two spin states can take any arbitrary value between zero and π , which can be measured as a phase shift between the two chiral states by using spin-echo techniques. Our result can be used to realize an electric-field-induced geometric phase-shift gate acting on a chiral qubit encoded in the ground-state manifold of the triangular magnetic molecule.

  10. Density functional theory and simulations of colloidal triangular prisms

    Science.gov (United States)

    Marechal, Matthieu; Dussi, Simone; Dijkstra, Marjolein

    2017-03-01

    Nanopolyhedra form a versatile toolbox to investigate the effect of particle shape on self-assembly. Here we consider rod-like triangular prisms to gauge the effect of the cross section of the rods on liquid crystal phase behavior. We also take this opportunity to implement and test a previously proposed version of fundamental measure density functional theory (0D-FMT). Additionally, we perform Monte Carlo computer simulations and we employ a simpler Onsager theory with a Parsons-Lee correction. Surprisingly and disappointingly, 0D-FMT does not perform better than the Tarazona and Rosenfeld's version of fundamental measure theory (TR-FMT). Both versions of FMT perform somewhat better than the Parsons-Lee theory. In addition, we find that the stability regime of the smectic phase is larger for triangular prisms than for spherocylinders and square prisms.

  11. Laterally Placed CDRA with Triangular Notches for Ultra Wideband Applications

    Science.gov (United States)

    Sankaranarayanan, Dileep; Venkata Kiran, Duggirala; Mukherjee, Biswajeet

    2017-12-01

    In this paper, a Coaxial probe-fed Laterally placed Cylindrical Dielectric Resonator Antenna (LCDRA) with symmetrical triangular notches is presented. The lateral surface of the Cylindrical Dielectric Resonator Antenna (CDRA) is kept on the ground plane with its longitudinal axis parallel to the ground plane. LCDRA has a lower resonant frequency than the CDRA and it offers considerably wider impedance bandwidth than CDRA. Finally, two symmetrical triangular notches are introduced on the two edges of LCDRA which is perpendicular to the axis to further improve the impedance bandwidth. The proposed antenna offers a wide impedance bandwidth (S_{11} <-10 dB) of 76.7 % (4.5-10.1 GHz). The radiation pattern of the proposed antenna is stable and broadside throughout the impedance bandwidth of operation. The prototype of the proposed antenna is fabricated and measured results are found to be in good agreement with the simulated one.

  12. Phase diagram of the triangular extended Hubbard model.

    Science.gov (United States)

    Tocchio, Luca F; Gros, Claudius; Zhang, Xue-Feng; Eggert, Sebastian

    2014-12-12

    We study the extended Hubbard model on the triangular lattice as a function of filling and interaction strength. The complex interplay of kinetic frustration and strong interactions on the triangular lattice leads to exotic phases where long-range charge order, antiferromagnetic order, and metallic conductivity can coexist. Variational Monte Carlo simulations show that three kinds of ordered metallic states are stable as a function of nearest neighbor interaction and filling. The coexistence of conductivity and order is explained by a separation into two functional classes of particles: part of them contributes to the stable order, while the other part forms a partially filled band on the remaining substructure. The relation to charge ordering in charge transfer salts is discussed.

  13. Block-triangular preconditioners for PDE-constrained optimization

    KAUST Repository

    Rees, Tyrone

    2010-11-26

    In this paper we investigate the possibility of using a block-triangular preconditioner for saddle point problems arising in PDE-constrained optimization. In particular, we focus on a conjugate gradient-type method introduced by Bramble and Pasciak that uses self-adjointness of the preconditioned system in a non-standard inner product. We show when the Chebyshev semi-iteration is used as a preconditioner for the relevant matrix blocks involving the finite element mass matrix that the main drawback of the Bramble-Pasciak method-the appropriate scaling of the preconditioners-is easily overcome. We present an eigenvalue analysis for the block-triangular preconditioners that gives convergence bounds in the non-standard inner product and illustrates their competitiveness on a number of computed examples. Copyright © 2010 John Wiley & Sons, Ltd.

  14. Triangular mattress suture in abdominal diastasis to prevent epigastric bulging.

    Science.gov (United States)

    Ferreira, L M; Castilho, H T; Hochberg, J; Ardenghy, M; Toledo, S R; Cruz, R G; Tardelli, H

    2001-02-01

    In the classic abdominoplasty, the treatment of large diastasis recti with simple or vertical mattress sutures may result in a nonaesthetic bulge. The surgeon may produce a craniocaudal bulge deformity by treating the flaccidity in the horizontal plane only, although it occurs in all directions. The authors describe the triangular mattress suture for the treatment of large diastasis recti, and demonstrate the mechanism involved in producing an epigastric bulge. Also presented is their clinical experience with 56 patients, with a 3-year follow-up, using this new plication method. The triangular mattress suture is a simple, quick, and effective way to correct abdominal diastasis and to avoid the epigastric bulge deformity with no added morbidity.

  15. Recurrence Relations for Orthogonal Polynomials on Triangular Domains

    Directory of Open Access Journals (Sweden)

    Abedallah Rababah

    2016-04-01

    Full Text Available In Farouki et al, 2003, Legendre-weighted orthogonal polynomials P n , r ( u , v , w , r = 0 , 1 , … , n , n ≥ 0 on the triangular domain T = { ( u , v , w : u , v , w ≥ 0 , u + v + w = 1 } are constructed, where u , v , w are the barycentric coordinates. Unfortunately, evaluating the explicit formulas requires many operations and is not very practical from an algorithmic point of view. Hence, there is a need for a more efficient alternative. A very convenient method for computing orthogonal polynomials is based on recurrence relations. Such recurrence relations are described in this paper for the triangular orthogonal polynomials, providing a simple and fast algorithm for their evaluation.

  16. Cluster-variation method for the triangular lattice gas

    Energy Technology Data Exchange (ETDEWEB)

    Osório, R.; Falicov, L. M.

    1981-05-28

    The triangular lattice gas is examined as a model for the ordering of Li+ ions in intercalated transition metal dichalcogenides. A three-sublattice Bragg~ Williams (point approximation) calculation illustrates the meaning of the features in the incremental capacity versus concentration curves: (a) minima are associated with ordered structures, (b) sharp maxima (divergences) are caused by the coexistence of ordered and disordered phases over small concentration intervals and (c) smooth maxima can be found at concentrations of no direct relevance to ordering.

  17. Procrustes Problems for General, Triangular, and Symmetric Toeplitz Matrices

    Directory of Open Access Journals (Sweden)

    Juan Yang

    2013-01-01

    Full Text Available The Toeplitz Procrustes problems are the least squares problems for the matrix equation AX=B over some Toeplitz matrix sets. In this paper the necessary and sufficient conditions are obtained about the existence and uniqueness for the solutions of the Toeplitz Procrustes problems when the unknown matrices are constrained to the general, the triangular, and the symmetric Toeplitz matrices, respectively. The algorithms are designed and the numerical examples show that these algorithms are feasible.

  18. Photonic Crystal Waveguides in Triangular Lattice of Nanopillars

    DEFF Research Database (Denmark)

    Chigrin, Dmitry N.; Lavrinenko, Andrei

    2004-01-01

    Photonic nanopillars waveguides have been analysed. Dielectric nanopillars are arranged in such way that they from a tringular lattice of 2D photonic crystal. Dispersion of the modes depends on the direction of the triangular lattice, Ã-J or Ã-X, in which nanopillars arrays are extended. Light fi....... Transmission spectra calculated by FDTD method completely reflect peculiarities of modes dispersion, showing up to 80% transmission for a realistic SOI nanopillar structure....

  19. A Step-Wise Approach to Elicit Triangular Distributions

    Science.gov (United States)

    Greenberg, Marc W.

    2013-01-01

    Adapt/combine known methods to demonstrate an expert judgment elicitation process that: 1.Models expert's inputs as a triangular distribution, 2.Incorporates techniques to account for expert bias and 3.Is structured in a way to help justify expert's inputs. This paper will show one way of "extracting" expert opinion for estimating purposes. Nevertheless, as with most subjective methods, there are many ways to do this.

  20. Amalric Triangular Syndrome Associated With Outer Nuclear Layer Infarction.

    Science.gov (United States)

    Garrity, Sean T; Holz, Eric J; Sarraf, David

    2017-08-01

    An 85-year-old man presented with temporal headache and bilateral paracentral scotomas. Clinical examination, laboratory testing, and temporal artery biopsy confirmed the diagnosis of giant cell arteritis. Fluorescein angiography illustrated Amalric triangular choroidal infarction of the left eye. Spectral-domain optical coherence tomography of the left eye demonstrated outer nuclear layer abnormalities adjacent to the choroidal infarct. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:668-670.]. Copyright 2017, SLACK Incorporated.

  1. Fabrication of Triangular Nanobeam Waveguide Networks in Bulk diamond Using Single-Crystal Silicon Hard Masks

    CERN Document Server

    Bayn, I; Li, L; Goldstein, J A; Schröder, T; Zhang, J; Chen, E H; Gaathon, O; Lu, M; Stein, A; Ruggiero, C A; Salzman, J; Kalish, R; Englund, D

    2014-01-01

    A scalable approach for integrated photonic networks in single-crystal diamond using triangular etching of bulk samples is presented. We describe designs of high quality factor (Q=2.51x10^6) photonic crystal cavities with low mode volume (Vm=1.062x({\\lambda}/n)^3), which are connected via waveguides supported by suspension structures with predicted transmission loss of only 0.05 dB. We demonstrate the fabrication of these structures using transferred single-crystal silicon hard masks and angular dry etching, yielding photonic crystal cavities in the visible spectrum with measured quality factors in excess of Q=3x103.

  2. Three-level schemes of the alternating triangular method

    Science.gov (United States)

    Vabishchevich, P. N.

    2014-06-01

    In this paper, the schemes of the alternating triangular method are set out in the class of splitting methods used for the approximate solution of Cauchy problems for evolutionary problems. These schemes are based on splitting the problem operator into two operators that are conjugate transposes of each other. Economical schemes for the numerical solution of boundary value problems for parabolic equations are designed on the basis of an explicit-implicit splitting of the problem operator. The alternating triangular method is also of interest for the construction of numerical algorithms that solve boundary value problems for systems of partial differential equations and vector systems. The conventional schemes of the alternating triangular method used for first-order evolutionary equations are two-level ones. The approximation properties of such splitting methods can be improved by transiting to three-level schemes. Their construction is based on a general principle for improving the properties of difference schemes, namely, on the regularization principle of A.A. Samarskii. The analysis conducted in this paper is based on the general stability (or correctness) theory of operator-difference schemes.

  3. Application of cylindrical, triangular and hemispherical dimples in the film cooling technology

    Science.gov (United States)

    Khalatov, A. A.; Panchenko, N. A.; Severin, S. D.

    2017-11-01

    The results of film cooling numerical simulation over a flat plate with coolant supply through a single span-wise array of inclined (α = 30°) holes arranged inside cylindrical, triangular, and hemispherical dimples are represented in the paper. Such configurations are of a great practical interest for application in advanced blade cooling systems of high-performance gas turbines. The schemes with coolant supply into triangular and hemispherical dimples were first proposed and patented by the IET of the NAS of Ukraine. For numerical simulation the ANSYS CFX 14 commercial code was used. Numerical simulation were carried out in a wide range of the blowing ratio parameter varied from 0.5 to 2.0. For low blowing ratio parameter (m = 0.5) the laterally averaged film cooling efficiency is actually the same for all investigated schemes over the main film cooling area. In this area, the most simple in terms of the film cooling production technology configuration can be used. At the medium and high blowing ratios (m = 1.0 or higher) all investigated film cooling schemes allow to increase the laterally averaged film cooling efficiency in comparison with the traditional cooling scheme with single row of incline holes. In this case the configuration with coolant supply into triangular dimples of the «crater» type demonstrates the best film cooling efficiency due to significant reduction in the intensity and scale of the “kidney” vortex beyond configuration, as well as due to decrease in the coolant blowing non-uniformity factor.

  4. A Novel Method for Multiattribute Decision Making with Dual Hesitant Fuzzy Triangular Linguistic Information

    Directory of Open Access Journals (Sweden)

    Yanbing Ju

    2014-01-01

    Full Text Available This paper studies the multiattribute decision making (MADM problems in which the attribute values take the form of dual hesitant fuzzy triangular linguistic elements and the weights of attributes take the form of real numbers. Firstly, to solve the situation where the membership degree and the nonmembership degree of an element to a triangular linguistic variable, the concept, operational laws, score function, and accuracy function of dual hesitant fuzzy triangular linguistic elements (DHFTLEs are defined. Then, some dual hesitant fuzzy triangular linguistic geometric aggregation operators are developed for aggregating the DHFTLEs, including dual hesitant fuzzy triangular linguistic weighted geometric (DHFTLWG operator, dual hesitant fuzzy triangular linguistic ordered weighted geometric (DHFTLOWG operator, dual hesitant fuzzy triangular linguistic hybrid geometric (DHFTLHG operator, generalized dual hesitant fuzzy triangular linguistic weighted geometric (GDHFTLWG operator, and generalized dual hesitant fuzzy triangular linguistic ordered weighted geometric (GDHFTLOWG operator. Furthermore, some desirable properties of these operators are investigated in detail. Based on the proposed operators, an approach to MADM with dual hesitant fuzzy triangular linguistic information is proposed. Finally, a numerical example for investment alternative selection is given to illustrate the application of the proposed method.

  5. Evidence for a spinon Fermi surface in a triangular-lattice quantum-spin-liquid candidate.

    Science.gov (United States)

    Shen, Yao; Li, Yao-Dong; Wo, Hongliang; Li, Yuesheng; Shen, Shoudong; Pan, Bingying; Wang, Qisi; Walker, H C; Steffens, P; Boehm, M; Hao, Yiqing; Quintero-Castro, D L; Harriger, L W; Frontzek, M D; Hao, Lijie; Meng, Siqin; Zhang, Qingming; Chen, Gang; Zhao, Jun

    2016-12-05

    A quantum spin liquid is an exotic quantum state of matter in which spins are highly entangled and remain disordered down to zero temperature. Such a state of matter is potentially relevant to high-temperature superconductivity and quantum-information applications, and experimental identification of a quantum spin liquid state is of fundamental importance for our understanding of quantum matter. Theoretical studies have proposed various quantum-spin-liquid ground states, most of which are characterized by exotic spin excitations with fractional quantum numbers (termed 'spinons'). Here we report neutron scattering measurements of the triangular-lattice antiferromagnet YbMgGaO4 that reveal broad spin excitations covering a wide region of the Brillouin zone. The observed diffusive spin excitation persists at the lowest measured energy and shows a clear upper excitation edge, consistent with the particle-hole excitation of a spinon Fermi surface. Our results therefore point to the existence of a quantum spin liquid state with a spinon Fermi surface in YbMgGaO4, which has a perfect spin-1/2 triangular lattice as in the original proposal of quantum spin liquids.

  6. Evidence for a spinon Fermi surface in a triangular-lattice quantum-spin-liquid candidate

    Science.gov (United States)

    Shen, Yao; Li, Yao-Dong; Wo, Hongliang; Li, Yuesheng; Shen, Shoudong; Pan, Bingying; Wang, Qisi; Walker, H. C.; Steffens, P.; Boehm, M.; Hao, Yiqing; Quintero-Castro, D. L.; Harriger, L. W.; Frontzek, M. D.; Hao, Lijie; Meng, Siqin; Zhang, Qingming; Chen, Gang; Zhao, Jun

    2016-12-01

    A quantum spin liquid is an exotic quantum state of matter in which spins are highly entangled and remain disordered down to zero temperature. Such a state of matter is potentially relevant to high-temperature superconductivity and quantum-information applications, and experimental identification of a quantum spin liquid state is of fundamental importance for our understanding of quantum matter. Theoretical studies have proposed various quantum-spin-liquid ground states, most of which are characterized by exotic spin excitations with fractional quantum numbers (termed ‘spinons’). Here we report neutron scattering measurements of the triangular-lattice antiferromagnet YbMgGaO4 that reveal broad spin excitations covering a wide region of the Brillouin zone. The observed diffusive spin excitation persists at the lowest measured energy and shows a clear upper excitation edge, consistent with the particle-hole excitation of a spinon Fermi surface. Our results therefore point to the existence of a quantum spin liquid state with a spinon Fermi surface in YbMgGaO4, which has a perfect spin-1/2 triangular lattice as in the original proposal of quantum spin liquids.

  7. Efficiency enhancement of ZnO nanostructure assisted Si solar cell based on fill factor enlargement and UV-blue spectral down-shifting

    Science.gov (United States)

    Gholizadeh, A.; Reyhani, A.; Parvin, P.; Mortazavi, S. Z.

    2017-05-01

    ZnO nanostructures (including nano-plates and nano-rods (NRs)) are grown in various temperatures and Ar/O2 flow rates using thermal chemical vapor deposition, which affect the structure, nano-plate/NR population, and the quality of ZnO nanostructures. X-ray diffraction (XRD) attests that the peak intensity of the crystallographic plane (1 0 0) is correlated to nano-plate abundance. Moreover, optical properties elucidate that the population of nano-plates in samples strongly affect the band gap, binding energy of the exciton, and UV-visible (UV-vis) absorption and spectral luminescence emissions. In fact, the exciton binding energy reduces from ~100 to 80 meV when the population of nano-plates increases in samples. Photovoltaic characteristics based on the drop-casting on Si solar cells reveals three dominant factors, namely, the equivalent series resistance, decreasing reflectance, and down-shifting, in order to scale up the absolute efficiency by 3%. As a consequence, the oxygen vacancies in ZnO nanostructures give rise to the down-shifting and increase of free-carriers, leading to a reduction in the equivalent series resistance and an enlargement of fill factor. To obtain a larger I sc, reduction of spectral reflectance is essential; however, the down-shifting process is shown to be dominant by lessening the surface electron-hole recombination rate over the UV-blue spectral range.

  8. THREE-SUBLATTICE MODEL FOR A TRIANGULAR LATTICE GAS

    Energy Technology Data Exchange (ETDEWEB)

    Osorlo, R.; Falicov, L.M.

    1980-03-01

    A three-sublattice Bragg-Williams model of a triangular lattice gas with repulsive nearest-neighbor interactions is presented. It is intended to represent intercalated Li{sup +} in Li{sub x}TiS{sub 2} . An order-disorder phase diagram and thermodynamic functions are computed. In particular the incremental capacity is calculated and compared with the experimental data of Thompson. It is found that (a) ordering results ln minima in the incremental capacity, (b) sharp maxirna (divergences) are caused by small regions of two-phase coexistence and (c) smooth maxima are found at concentrations of no relevance to ordering.

  9. Diffraction pattern of triangular grating in the resonance domain.

    Science.gov (United States)

    Hoshino, Tetsuya; Banerjee, Saswatee; Itoh, Masahide; Yatagai, Toyohiko

    2009-03-01

    We propose a combination of ray optics and Fraunhofer multiple-slit diffraction theory for calculating the two-dimensional triangular periodic grating in the resonance domain. The peak of the envelope pattern of angular distribution of diffraction efficiency is calculated by ray optics while the peak width is calculated using Fraunhofer theory. It was clarified, using rigorous coupled-wave analysis and a nonstandard-finite-difference time-domain method, that the envelope pattern of the diffraction of the grating could be calculated easily and understood intuitively for the design of displays and lighting.

  10. A flat triangular shell element with Loof nodes

    DEFF Research Database (Denmark)

    Poulsen, Peter Noe; Damkilde, Lars

    1996-01-01

    In the formulation of flat shell elements it is difficult to achieve inter-element compatibility between membrane and transverse displacements for non-coplanar elements. Many elements lack proper nodal degrees of freedom to model intersections making the assembly of elements troublesome. A flat...... triangular shell element is established by a combination of a new plate bending element DKTL and the well-known linear membrane strain element LST, and for this element the above-mentioned deficiences are avoided. The plate bending element DKTL is based on Discrete Kirchhoff Theory and Loof nodes. The nodal...

  11. Triangular and Trapezoidal Fuzzy State Estimation with Uncertainty on Measurements

    Directory of Open Access Journals (Sweden)

    Mohammad Sadeghi Sarcheshmah

    2012-01-01

    Full Text Available In this paper, a new method for uncertainty analysis in fuzzy state estimation is proposed. The uncertainty is expressed in measurements. Uncertainties in measurements are modelled with different fuzzy membership functions (triangular and trapezoidal. To find the fuzzy distribution of any state variable, the problem is formulated as a constrained linear programming (LP optimization. The viability of the proposed method would be verified with the ones obtained from the weighted least squares (WLS and the fuzzy state estimation (FSE in the 6-bus system and in the IEEE-14 and 30 bus system.

  12. Small and Sharp Triangular Silver Nanoplates Synthesized Utilizing Tiny Triangular Nuclei and Their Excellent SERS Activity for Selective Detection of Thiram Residue in Soil.

    Science.gov (United States)

    Zhang, Chun-Hong; Zhu, Jian; Li, Jian-Jun; Zhao, Jun-Wu

    2017-05-24

    The great harm of thiram residue in soil to environment and human health is usually ignored. Due to the complexity of soil compositions, the detection of thiram residue in soil faces considerable difficulties. In this work, a highly sensitive and selective surface-enhanced Raman scattering (SERS) substrate based on the triangular silver nanoplates (TSNPs) with small size and sharp corners is developed and used for the detection of thiram residue in soil for the first time. These TSNPs are synthesized by replacing the conventional seeds in the seed-mediated chemical reduction route with the tiny and uniform triangular silver nuclei (TSN) which can provide more growing space for generating sharp corners during the growth of TSNPs. It is interesting that the TSNPs with the smaller size have the better SERS performance. The possible mechanism behind this phenomenon is explained by the electromagnetic enhancement theory. On the basis of the Raman activity of the smallest TSNPs, a SERS-active substrate is prepared for detecting the thiram residue in soil. The thiram solution detection shows that the limit of detection (LOD) of these smallest TSNPs is lower than other nanoparticles, such as nanospheres, nanocubes, etc. For sensing the thiram residue in soil, the addition of poly(sodium 4-styrenesulfonate) realizes the specific adsorption of thiram by TSNPs. This method exhibits a good linear response from 0.12 to 4.8 μg/g with a low LOD of 90 ng/g, which is better than conventional methods. This work shows the great potential of the small TSNPs as a novel SERS substrate and its broader applications in pesticides detection.

  13. GPU-Accelerated Population Annealing Algorithm: Frustrated Ising Antiferromagnet on the Stacked Triangular Lattice

    Directory of Open Access Journals (Sweden)

    Borovský Michal

    2016-01-01

    Full Text Available The population annealing algorithm is a novel approach to study systems with rough free-energy landscapes, such as spin glasses. It combines the power of simulated annealing, Boltzmann weighted differential reproduction and sequential Monte Carlo process to bring the population of replicas to the equilibrium even in the low-temperature region. Moreover, it provides a very good estimate of the free energy. The fact that population annealing algorithm is performed over a large number of replicas with many spin updates, makes it a good candidate for massive parallelism. We chose the GPU programming using a CUDA implementation to create a highly optimized simulation. It has been previously shown for the frustrated Ising antiferromagnet on the stacked triangular lattice with a ferromagnetic interlayer coupling, that standard Markov Chain Monte Carlo simulations fail to equilibrate at low temperatures due to the effect of kinetic freezing of the ferromagnetically ordered chains. We applied the population annealing to study the case with the isotropic intra- and interlayer antiferromagnetic coupling (J2/|J1| = −1. The reached ground states correspond to non-magnetic degenerate states, where chains are antiferromagnetically ordered, but there is no long-range ordering between them, which is analogical with Wannier phase of the 2D triangular Ising antiferromagnet.

  14. Mean streamwise velocity measurements in a triple jet of equilateral triangular configuration

    Energy Technology Data Exchange (ETDEWEB)

    Moustafa, G.H. (Menoufia Univ. (Egypt). Coll. of Engineering); Sundararajan, T. (IIT Kanpur (India). Dept. of Mechanical Engineering); Rathakrishnan, E. (IIT Kanpur (India). Dept. of Aerospace Engineering)

    1993-09-01

    Multijet flows arise in several applications such as jet engine/rocket combustors, the thrust augmenting ejectors for VTOL/STOL aircraft, and industrial gas burners. In order to achieve proper combustion, thrust development, and reduction in the noise level, it is often desirable to control the inter-mixing between the jets and also the entrainment of the surrounding atmosphere. This, in turn, requires a detailed study of the behavior of high speed jets in multijet configuration. The situation of interest here is an array of three axisymmetric nozzles set in a common end wall with equal spacing in a triangular configuration. The reason why this particular configuration has been chosen is that it promotes bending of the jet axes toward each other, thus leading to greater mixing. In the present study, experiments have been conducted to investigate the effect of stagnation pressure ratio and nozzle spacing upon the mean flow characteristic of compressible jets in triangular configuration. The individual flow features of the vertex jet and the base twin jet are analyzed and their contributions to the axis switching as well as the overall triple jet behavior are highlighted.

  15. Numerical investigation of Al2O3/water nanofluid laminar convective heat transfer through triangular ducts

    Directory of Open Access Journals (Sweden)

    Zeinali Heris Saeed

    2011-01-01

    Full Text Available Abstract In this article, laminar flow-forced convective heat transfer of Al2O3/water nanofluid in a triangular duct under constant wall temperature condition is investigated numerically. In this investigation, the effects of parameters, such as nanoparticles diameter, concentration, and Reynolds number on the enhancement of nanofluids heat transfer is studied. Besides, the comparison between nanofluid and pure fluid heat transfer is achieved in this article. Sometimes, because of pressure drop limitations, the need for non-circular ducts arises in many heat transfer applications. The low heat transfer rate of non-circular ducts is one the limitations of these systems, and utilization of nanofluid instead of pure fluid because of its potential to increase heat transfer of system can compensate this problem. In this article, for considering the presence of nanoparticl: es, the dispersion model is used. Numerical results represent an enhancement of heat transfer of fluid associated with changing to the suspension of nanometer-sized particles in the triangular duct. The results of the present model indicate that the nanofluid Nusselt number increases with increasing concentration of nanoparticles and decreasing diameter. Also, the enhancement of the fluid heat transfer becomes better at high Re in laminar flow with the addition of nanoparticles.

  16. On the interference rejection capabilities of triangular antenna array for cellular base stations

    KAUST Repository

    Atat, Rachad

    2012-03-01

    In this paper, we present the performance analysis of the triangular antenna arrays in terms of the interference rejection capability. In this context, we derive an expression to calculate the spatial interference suppression coefficient for the triangular antenna array with variable number of antenna elements. The performance of the triangular antenna array has been compared with the circular antenna array with respect to interference suppression performance, steering beam pattern, beamwidth and directivity. Simulation results show that the triangular array with large number of elements produces a sharper beamwidth and better interference suppression performance than the circular antenna array. © 2012 IEEE.

  17. Analysis of moving bottlenecks considering a triangular fundamental diagram

    Directory of Open Access Journals (Sweden)

    Karim Fadhloun

    2016-10-01

    Full Text Available A significant number of research efforts have studied and analyzed the case in which a vehicle is moving slower than the traffic stream. This phenomenon, known as a moving bottleneck, results in a disruption of traffic flow and may significantly impact the traffic stream behavior upstream, downstream and abreast the slow moving vehicle. In this paper, a macroscopic approach for modeling moving bottlenecks is developed using microscopically derived data considering a triangular fundamental diagram. The passing flow rates of different moving bottleneck scenarios are determined using a previously developed microscopic model based on simulated data derived from the INTEGRATION software. Using the simulation results, an explicit expression of the bottleneck diagram, a flow-density relationship that defines the phenomenon macroscopically is proposed and the behavior of the traffic stream downstream and abreast the moving obstruction is depicted. It is demonstrated that the behavior of the traffic stream downstream of the slow vehicle as well as the acceleration behavior while passing is governed by the demand level. Such a result is coherent and consistent, to a significant extent, with two decades of research related to modeling moving bottlenecks and constitutes a potential feasible and more detailed description of the phenomenon in the case of a triangular fundamental diagram. Finally, it is noteworthy that the research subject of this paper could be considered as a first step in developing a numerical and practitioner-friendly framework for the analysis of moving bottlenecks that does not involve approaching the problem from its theoretical perspective.

  18. Corrosion processes of triangular silver nanoparticles compared to bulk silver

    Energy Technology Data Exchange (ETDEWEB)

    Keast, V. J., E-mail: vicki.keast@newcastle.edu.au; Myles, T. A. [University of Newcastle, School of Mathematical and Physical Sciences (Australia); Shahcheraghi, N.; Cortie, M. B. [University of Technology Sydney, Institute for Nanoscale Technology (Australia)

    2016-02-15

    Excessive corrosion of silver nanoparticles is a significant impediment to their use in a variety of potential applications in the biosensing, plasmonic and antimicrobial fields. Here we examine the environmental degradation of triangular silver nanoparticles (AgNP) in laboratory air. In the early stages of corrosion, transmission electron microscopy shows that dissolution of the single-crystal, triangular, AgNP (side lengths 50–120 nm) is observed with the accompanying formation of smaller, polycrystalline Ag particles nearby. The new particles are then observed to corrode to Ag{sub 2}S and after 21 days nearly full corrosion has occurred, but some with minor Ag inclusions remaining. In contrast, a bulk Ag sheet, studied in cross section, showed an adherent corrosion layer of only around 20–50 nm in thickness after over a decade of being exposed to ambient air. The results have implications for antibacterial properties and ecotoxicology of AgNP during corrosion as the dissolution and reformation of Ag particles during corrosion will likely be accompanied by the release of Ag{sup +} ions.

  19. Automatic Generation of Facial Expression Using Triangular Geometric Deformation

    Directory of Open Access Journals (Sweden)

    Jia-Shing Sheu

    2014-12-01

    Full Text Available This paper presents an image deformation algorithm and constructs an automatic facial expression generation system to generate new facial expressions in neutral state. After the users input the face image in a neutral state into the system, the system separates the possible facial areas and the image background by skin color segmentation. It then uses the morphological operation to remove noise and to capture the organs of facial expression, such as the eyes, mouth, eyebrow, and nose. The feature control points are labeled according to the feature points (FPs defined by MPEG-4. After the designation of the deformation expression, the system also increases the image correction points based on the obtained FP coordinates. The FPs are utilized as image deformation units by triangular segmentation. The triangle is split into two vectors. The triangle points are regarded as linear combinations of two vectors, and the coefficients of the linear combinations correspond to the triangular vectors of the original image. Next, the corresponding coordinates are obtained to complete the image correction by image interpolation technology to generate the new expression. As for the proposed deformation algorithm, 10 additional correction points are generated in the positions corresponding to the FPs obtained according to MPEG-4. Obtaining the correction points within a very short operation time is easy. Using a particular triangulation for deformation can extend the material area without narrowing the unwanted material area, thus saving the filling material operation in some areas.

  20. A systematic study of triangular silver nanoplates: one-pot green synthesis, chemical stability, and sensing application.

    Science.gov (United States)

    Wijaya, Yosia Nico; Kim, Jinwoo; Choi, Won Mook; Park, Sung Hwan; Kim, Mun Ho

    2017-08-17

    While there has been remarkable success in generating silver (Ag) nanoplates, and they have considerable potential applications, their degradation behavior in certain environments remains poorly understood. In the current work, we investigated the chemical stability of triangular Ag nanoplates. A one-step water-based synthesis method regulated by the coordination of ligands to Ag cations was successfully employed to produce triangular Ag nanoplates with a high yield. The Ag nanoplates were irreversibly degraded when they were aged with poly(styrene-4-sulfonate) (PSS) at room temperature, and the corresponding localized surface plasmon resonances (LSPR) of the Ag nanoplates changed as well. In contrast, when the Ag nanoplates were aged with potassium persulfate (KPS), the shape evolution of Ag nanoplates was found to depend on the external temperature, and the Ag nanoplate solutions showed different final colors when different external temperatures were applied. These results exhibit important implications for the behavior of triangular Ag nanoplates in a wide variety of plasmonic applications and can be applied to the colorimetric sensing of the temperature history.

  1. The effects of computed tomography scanner parameters on the quality of the reverse triangular surface model of the fibula

    Energy Technology Data Exchange (ETDEWEB)

    Hayat, Nasir; Ahmad, Mushtaq, E-mail: nasirhayat@uet.edu.pk [Faculty of Mechanical Engineering, UET, Lahore (Pakistan)

    2016-01-15

    This study investigates the effects of computed tomography (CT) parameters on the quality and size of the reverse triangular surface model with an objective of obtaining an accurate 3D triangular surface model of complex-shaped customized objects for reverse engineering and many other applications such as surgical planning and finite element analysis. For this purpose, the fibula of a human knee joint was CT scanned by changing various parameters (slice thickness, slice spacing, pixel size, X-ray tube current and helical pitch) over wide ranges. Three-dimensional triangular surface models were created from point cloud data extracted from the CT image data. To assess the influences of scanning parameters on the surface quality and accuracy, the resulting surface models were qualitatively compared based on various anatomical features. Statistical analysis was used to quantify the deviations of surface models with different scanning parameter levels from the reference CT surface model. The results show that these parameters to a varying degree affect the surface quality, reproduction of various anatomical details and size of the resulting surface model. Moreover, these parameters are highly dependent on each other. Interactive effects of these parameters have been discussed and recommendations have been made for parameter settings. The results of the study would help to improve the accuracy of the 3D surface models required for customized implants and other applications. (author)

  2. Facile synthesis of MoS2 and MoxW1-xS2 triangular monolayers

    Directory of Open Access Journals (Sweden)

    Zhong Lin

    2014-09-01

    Full Text Available Single- and few-layered transition metal dichalcogenides, such as MoS2 and WS2, are emerging two-dimensional materials exhibiting numerous and unusual physico-chemical properties that could be advantageous in the fabrication of unprecedented optoelectronic devices. Here we report a novel and alternative route to synthesize triangular monocrystals of MoS2 and MoxW1-xS2 by annealing MoS2 and MoS2/WO3 precursors, respectively, in the presence of sulfur vapor. In particular, the MoxW1-xS2 triangular monolayers show gradual concentration profiles of W and Mo whereby Mo concentrates in the islands’ center and W is more abundant on the outskirts of the triangular monocrystals. These observations were confirmed by atomic force microscopy, and high-resolution transmission electron microscopy, as well as Raman and photoluminescence spectroscopy. The presence of tunable PL signals depending on the MoxW1-xS2 stoichiometries in 2D monocrystals opens up a wide range of applications in electronics and optoelectronics.

  3. The Preterm Infant's Use of Triangular Bids at Three Months, Adjusted Age: Two Case Studies

    Science.gov (United States)

    Hansen, Ellen Saeter

    2011-01-01

    This article focuses on preterm infants' early triangular capacity, restricted to the use of triangular bids in interaction with their parents. An observational setting, the Lausanne Trilogue Play (LTP), is used for studying the patterns of interaction. This is an approach focusing on the family as a whole. These observations are part of a study…

  4. Bilateral Temporal Triangular Alopecia Associated with Phakomatosis Pigmentovascularis Type IV Successfully Treated with Follicular Unit Transplantation

    Directory of Open Access Journals (Sweden)

    Robin Unger

    2011-01-01

    Full Text Available Temporal triangular alopecia (TTA, also known as congenital triangular alopecia, is a nonscarring, noninflammatroy, circumscribed form of alopecia. TTA has been associated with several disorders, such as Phakomatosis Pigmentovascularis. Hair restoration surgery using follicular unit transplantation has been a successful treatment modality for TTA. Herein we report such a success that was sustained for over six years.

  5. Chemical signals turn on guest binding through structural reconfiguration of triangular helicates

    DEFF Research Database (Denmark)

    Sørensen, Anne; Castilla, Ana M.; Ronson, Tanya K.

    2013-01-01

    Be my guest: The function of a system based on self-assembled Zn(II) complexes can be controlled by external chemical stimuli. The complexes are based on a C3 -symmetric ligand that forms a unique triangular triple helicate structure 1. Upon subcomponent substitution, 1 is able to transform into ...... into a triangular double helicate 2 which, unlike 1, can encapsulate guests....

  6. Self-assembly of triangular quantum dots on (111)A substrates by droplet epitaxy

    Energy Technology Data Exchange (ETDEWEB)

    Jo, M.; Mano, T.; Abbarchi, M.; Kuroda, T. [Advanced Photonics Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Sakoda, K. [Advanced Photonics Materials Unit, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan and Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan)

    2014-05-15

    We report the self-assembly of triangular GaAs quantum dots (QDs) on (111)A substrates using droplet epitaxy. Shape transition from hexagonal to triangular QDs is observed with increasing crystallizing temperature. The mechanism of the morphological change is discussed in terms of different growth rates of step edges on a (111)A substrate.

  7. Electromagnetic Scattering at the Waveguide Step between Equilateral Triangular Waveguides

    Directory of Open Access Journals (Sweden)

    Ana Morán-López

    2016-01-01

    Full Text Available The analysis of the electromagnetic scattering at discontinuities between equilateral triangular waveguides is studied. The complete electromagnetic solution is derived using analytical closed form expressions for the mode spectrum of the equilateral waveguide. The mathematical formulation of the electromagnetic scattering problem is based on the quasi-analytical Mode-Matching method. This method benefits from the electromagnetic field division into symmetries as well as from the plane wave formulation presented for the expressions involved. The unification of the surface integrals used in the method thanks to the plane wave formulation is revealed, leading to expressions that are very well suited for its implementation in an electromagnetic analysis and design code. The obtained results for some cases of interest (building blocks for microwave components for communication systems are verified using other numerical methods included in a commercial software package, showing the potential of the presented approach based on quasi-analytic expressions.

  8. Robust watermarking based on the warping of predefined triangular patterns

    Science.gov (United States)

    Bas, Patrick; Chassery, Jean-Marc; Macq, Benoit M. M.

    2000-05-01

    Numerical information is volatile and watermarking is a solution to assist copyright protection. During the detection step, the synchronization of the mark is a great problem. Geometric transformations can defeat the detector of the mark by desynchronizing the mark. Our scheme is based on warping of pre-defined triangular patterns. The content of the image (feature points) is used to mark independently different regions. This allows the synchronization of the mark for the detection step. Feature points mixed with a Delaunay tessellation permits to mark each triangle of the image. The detection is performed by warping triangle to a reference pattern and correlating with a reference triangle. Different algorithms have been developed in the spatial domain and in the frequential (DCT) domain. Our results show that our schemes are robust to Stirmark and other geometric transformations on different categories of images.

  9. Isotropy dependence of spiral order in triangular lattice Hubbard model

    Directory of Open Access Journals (Sweden)

    P Sahebsara

    2016-06-01

    Full Text Available Investigation of broken symmetry phases with long range order in strongly correlated electron systems is among subjects that have always been of interest to condensed matter scientists. In this paper we tried to study the existence of the 120 degrees magnetic spiral order, based on anisotropy in geometrically frustrated triangular lattices, using variational cluster approximation. We observed that by increasing the anisotropy in the system, the spiral order can be found for U≥7.5t and for t'<1.35; however, it is limited by decreasing t' since antiferromagnetism is dominant for t'<0.85t. Studying the Mott transition shows that a paramagnetic insulating phase, called quantum spin liquid, happens in the neighborhood of the spiral ordered phase

  10. Quantum Paramagnet in a π Flux Triangular Lattice Hubbard Model.

    Science.gov (United States)

    Rachel, Stephan; Laubach, Manuel; Reuther, Johannes; Thomale, Ronny

    2015-04-24

    We propose the π flux triangular lattice Hubbard model (π THM) as a prototypical setup to stabilize magnetically disordered quantum states of matter in the presence of charge fluctuations. The quantum paramagnetic domain of the π THM that we identify for intermediate Hubbard U is framed by a Dirac semimetal for weak coupling and by 120° Néel order for strong coupling. Generalizing the Klein duality from spin Hamiltonians to tight-binding models, the π THM maps to a Hubbard model which corresponds to the (J_{H},J_{K})=(-1,2) Heisenberg-Kitaev model in its strong coupling limit. The π THM provides a promising microscopic testing ground for exotic finite-U spin liquid ground states amenable to numerical investigation.

  11. Incommensurate correlations in the anisotropic triangular Heisenberg lattice

    Science.gov (United States)

    Weichselbaum, Andreas; White, Steven R.

    2011-12-01

    We study the anisotropic spin-1/2 antiferromagnetic triangular Heisenberg lattice in two dimensions, seen as a set of chains with couplings J (J') along (in-between) chains, respectively. Our focus is on the incommensurate correlation that emerges in this system in a wide parameter range due to the intrinsic frustration of the spins. We study this system with traditional density matrix renormalization group using cylindrical boundary conditions to least constrain possible incommensurate order. Despite that the limit of essentially decoupled chains J'/J≲0.5 is not very accessible numerically, it appears that the spin-spin correlations remain incommensurate for any finite 0JC', where JC'/J>1. The incommensurate wave vector qJ, however, approaches the commensurate value corresponding to the antiferromagnetic correlation of a single chain very rapidly with decreasing J'/J, roughly as qJ˜π-c1(J'/J)ne-c2J/J'.

  12. Higher-order hybrid stress triangular Mindlin plate element

    Science.gov (United States)

    Li, Tan; Ma, Xu; Xili, Jing; Chen, Wanji

    2016-12-01

    A 6-node triangular hybrid stress element is presented for Mindlin plate in this paper. The proposed element, denoted by TH6-27β, can pass both the zero shear stress patch test and the non-zero constant shear stress enhanced patch test and, it can be employed to analyze very thin plate. To accomplish this purpose, special attention is devoted to selecting boundary displacement interpolation and stress approximation in domain. The arbitrary order Timoshenko beam function is used successfully to derive the displacement interpolation along each side of the element. According to the equilibrium equations, an appropriate stress approximation is rationally obtained. The assumed stress field is modified by using 27β instead of 15β to improve the accuracy. Numerical results show that the element is free of shear locking, and reliable for thick and thin plates. Moreover, it has no spurious zero energy modes and with geometric invariance (coordinate invariance, node sequencing independence).

  13. Triangular and Y-shaped hadrons in QCD

    Energy Technology Data Exchange (ETDEWEB)

    D. S. Kuzmenko; Yu. A. Simonov

    2002-03-01

    Gauge invariant extended configurations are considered for 3 fundamental (quarks) or adjoint (gluons) particles. For 3 quarks it is proved that the only possible gauge-invariant configuration is the Y-shaped one, proposed long ago, while the triangular one proposed recently is ruled out. For adjoint sources both configurations are possible. Static potential is computed in all cases. For baryons the Y-shaped configuration leads to a significant depletion of field-strength density at the string-junction position, which decreases the effective potential slope at R {approx} 0.5 fm by 10-15%, as observed on the lattice. For adjoint sources the Y-shaped and {Delta}-shaped potentials are very close, leading to almost degenerate masses of 3--3g glueballs and odderon trajectories.

  14. Simplified analysis of sub-wavelength triangular gratings by simplified modal method.

    Science.gov (United States)

    Sridharan, Gayathri; Bhattacharya, Shanti

    2016-12-01

    A phase-equivalence of a triangular grating and a "corresponding" blazed structure is proposed. This equivalence is used to simplify the analysis of the grating, which otherwise would require the repetitive application of the simplified modal method to each lamellar grating that constitutes the triangular grating. The concept is used to arrive at an equation for the phase introduced by the triangular grating. The proposed model is verified by finite element simulations. A method of fabricating a triangular grating in quartz is presented. The proposed theory, along with optical testing, can be used as a non-destructive means by which to estimate the height of the triangular grating during the dry etching process.

  15. Fermi condensation near van Hove singularities within the Hubbard model on the triangular lattice.

    Science.gov (United States)

    Yudin, Dmitry; Hirschmeier, Daniel; Hafermann, Hartmut; Eriksson, Olle; Lichtenstein, Alexander I; Katsnelson, Mikhail I

    2014-02-21

    The proximity of the Fermi surface to van Hove singularities drastically enhances interaction effects and leads to essentially new physics. In this work we address the formation of flat bands ("Fermi condensation") within the Hubbard model on the triangular lattice and provide a detailed analysis from an analytical and numerical perspective. To describe the effect we consider both weak-coupling and strong-coupling approaches, namely the renormalization group and dual fermion methods. It is shown that the band flattening is driven by correlations and is well pronounced even at sufficiently high temperatures, of the order of 0.1-0.2 of the hopping parameter. The effect can therefore be probed in experiments with ultracold fermions in optical lattices.

  16. Numerical linked-cluster algorithms. I. Spin systems on square, triangular, and kagomé lattices.

    Science.gov (United States)

    Rigol, Marcos; Bryant, Tyler; Singh, Rajiv R P

    2007-06-01

    We discuss recently introduced numerical linked-cluster (NLC) algorithms that allow one to obtain temperature-dependent properties of quantum lattice models, in the thermodynamic limit, from exact diagonalization of finite clusters. We present studies of thermodynamic observables for spin models on square, triangular, and kagomé lattices. Results for several choices of clusters and extrapolations methods, that accelerate the convergence of NLCs, are presented. We also include a comparison of NLC results with those obtained from exact analytical expressions (where available), high-temperature expansions (HTE), exact diagonalization (ED) of finite periodic systems, and quantum Monte Carlo simulations. For many models and properties NLC results are substantially more accurate than HTE and ED.

  17. Ultrahigh magnetic field phases in the frustrated triangular-lattice magnet CuCrO2

    Science.gov (United States)

    Miyata, Atsuhiko; Portugall, Oliver; Nakamura, Daisuke; Ohgushi, Kenya; Takeyama, Shojiro

    2017-11-01

    The magnetic phases of a triangular-lattice antiferromagnet CuCrO2 were investigated in magnetic fields along the c axis, H ∥[001 ] , up to 120 T. Faraday rotation and magnetoabsorption spectroscopy were used to unveil the rich physics of magnetic phases. An up-up-down (UUD) magnetic structure phase was observed around 90-105 T at temperatures around 10 K. Additional distinct anomalies adjacent to the UUD phase were uncovered and the Y -shaped and the V -shaped phases are proposed to be viable candidates. These ordered phases emerged as a result of the interplay of geometrical spin frustration, single-ion anisotropy, and thermal fluctuations in an environment of extremely high magnetic fields.

  18. Effect of variation of I{sub 01}/I{sub 02} on short-circuit current and fill factor of a real solar cell having resistive and current leakage losses

    Energy Technology Data Exchange (ETDEWEB)

    Dadu, M.; Kapoor, A.; Tripathi, K.N. [Department of Electronic Sciences, University of Delhi, South Campus, Benito Juarez Road, -110021 New Delhi (India)

    2001-11-01

    We analyze the effect of variation of I{sub 01}/I{sub 02} on short-circuit current and the fill factor of a solar cell having resistive and current leakage losses. This analysis is particularly important for the polycrystalline solar cells, where higher values of I{sub 02} and hence lower values of I{sub 01}/I{sub 02} can be expected due to the space charge regions associated with the grain boundaries. Also in polycrystalline solar cells, we cannot ignore the effect of series and shunt resistances. It is observed that the value of fill factor depends on R{sub s}, R{sub sh} and I{sub 01}/I{sub 02}, while the value of I{sub sc} depends only on R{sub s} and I{sub 01}/I{sub 02}.

  19. Parametric study on shear behaviour for triangular web profile steel section with openings

    Science.gov (United States)

    De'nan, Fatimah; Keong, Choong Kok; Hashim, Nor Salwani; Yan, Kong Jing

    2017-10-01

    The cost of steel section had been the important factor in design process. Hence, triangular web profile which has higher shear capacity than normal flat web had been introduced. In order to reduce the steel weight, opening in web had been introduced. In this paper, a numerical study on shear strength for triangular web profile steel section with opening is carried out. A total of four various opening shapes and sizes of triangular web profile steel section are developed. A comparison of finite element analysis results on triangular web profile steel section with various web openings is reported. Overall results show that in term of deformed shapes, each model of the triangular web profile steel section with openings behave similarly. Triangular web profile steel section without opening has higher ultimate shear strength compared with triangular web profile steel section with openings. The best shape of opening is diamond shape because it's give highest shear buckling capacity compared to circle, square and hexagon shape openings. Reduction in volume for diamond shape is lesser than the reduction in volume for circle, square and hexagon shape openings. The reduction in volume decreases, as the opening size decreases.

  20. Fraunhofer diffraction of Laguerre-Gaussian beam caused by a dynamic superposed dual-triangular aperture

    Science.gov (United States)

    Li, Xinzhong; Tai, Yuping; Nie, Zhaogang; Wang, Hui; Li, Hehe; Wang, Jingge; Tang, Jie; Wang, Yishan

    2015-12-01

    We investigate the Fraunhofer diffraction of a Laguerre-Gaussian (LG) beam incident on a dynamic superposed dual-triangular aperture. The evolution of the diffraction pattern from this aperture is analyzed experimentally and theoretically. A special aperture, called the hex-star triangular aperture, demonstrates interesting diffraction patterns. Further, the diffraction properties of integer, half-integer, and fractional orders of topological charges at the Fraunhofer zone are studied by using the hex-star triangular aperture. This study can provide additional information to enhance the understanding of the diffraction properties of the LG beam transmitted through a complex aperture.

  1. Fault Diagnosis of Nonlinear Uncertain Systems with Triangular Form

    Directory of Open Access Journals (Sweden)

    Qi Ding

    2017-01-01

    Full Text Available A novel approach to fault diagnosis for a class of nonlinear uncertain systems with triangular form is proposed in this paper. It is based on the extended state observer (ESO of the active disturbance rejection controller and linearization of dynamic compensation. Firstly, an ESO is designed to jointly estimate the states and the combination of uncertainty, faults, and nonlinear function of nonlinear uncertain systems. It can derive the estimation of nonlinear function via the state estimations and system model. Then, linearization of dynamic compensation is employed to linearize the system by offsetting nonlinear function mandatorily using its estimation. An observer-based residual generator is designed on the basis of the prior linearized model for fault diagnosis. Moreover, threshold treatment technique is adopted to improve the robustness of fault diagnosis. This method is utilizable and simple in construction and parameter tuning. And also we show the construction of ESO and give the corresponding convergence proof succinctly. Finally, a numerical example is presented to illustrate the validity of the proposed fault diagnosis scheme.

  2. Magnetic properties in stacked triangular lattice: Monte Carlo approach

    Science.gov (United States)

    Masrour, R.; Jabar, A.

    2018-02-01

    We study the magnetic properties of mixed spins σ = 5 / 2 and S = 2 Ising in stacked triangular lattice (STL) using Monte Carlo approach. We have also give the grounds state phase diagrams of mixed spins-5/2 and 2. The different magnetic phases are detected under effect of different physical parameters. The diagrams show some key features: coexistence between regions, points where three, four and five states can coexist. The reduced critical temperatures have been also determined for different exchange interactions in each layer with a fixed value of exchange interactions between two layers. The total magnetization with reduced exchange interactions and crystal-fields of mixed spins is obtained. The multiple hysteresis and the superparamagnetic behavior are established around the reduced critical temperatures. The magnetic coercive field and magnetization remanent increase with increasing the exchange interactions and decreases with increasing the temperature values. The obtained results are similar to those obtained by experiment and theoretically results. Above reduced transition temperature the system shows superparamagnetic behavior which makes the material desirable for biomedical applications.

  3. Triangular platinum(II) metallacycles: syntheses, photophysics, and nonlinear optics.

    Science.gov (United States)

    Fan, Yuanpeng; Zhao, Dahui

    2015-03-25

    Three triangular platinum(II) diimine metallacycles incorporating large cyclic oligo(phenylene-ethynylene) (OPE) bisacetylide ligands are synthesized, and their photophysical properties are studied. Two types of triplet excited states with ligand/metal-to-ligand charge-transfer and acetylide-ligand-centered characteristics respectively, are exhibited by these complexes depending on the size (conjugation length) and electronic features of the cyclic OPE ligands. When the energy levels of the two excited states are close to each other, the lowest triplet state is found to switch between the two in varied solvents, resulting from their relative energy inversion induced by solvent polarity change. Density functional theory and time-dependent density functional theory calculations provide corroborative evidence for such experimental conclusions. More importantly, the designed metallacycles show impressive two-photon absorption (2PA) and two-photon excitation phosphorescing abilities, and the 2PA cross section reaches 1020 GM at 680 nm and 670 GM at 1040 nm by two different metallacycles. Additionally, pronounced reverse saturable absorptions are observed with these metallacycles by virtue of their strong transient triplet-state absorptions.

  4. Quantum electric-dipole liquid on a triangular lattice.

    Science.gov (United States)

    Shen, Shi-Peng; Wu, Jia-Chuan; Song, Jun-Da; Sun, Xue-Feng; Yang, Yi-Feng; Chai, Yi-Sheng; Shang, Da-Shan; Wang, Shou-Guo; Scott, James F; Sun, Young

    2016-02-04

    Geometric frustration and quantum fluctuations may prohibit the formation of long-range ordering even at the lowest temperature, and therefore liquid-like ground states could be expected. A good example is the quantum spin liquid in frustrated magnets. Geometric frustration and quantum fluctuations can happen beyond magnetic systems. Here we propose that quantum electric-dipole liquids, analogues of quantum spin liquids, could emerge in frustrated dielectrics where antiferroelectrically coupled electric dipoles reside on a triangular lattice. The quantum paraelectric hexaferrite BaFe12O19 with geometric frustration represents a promising candidate for the proposed electric-dipole liquid. We present a series of experimental lines of evidence, including dielectric permittivity, heat capacity and thermal conductivity measured down to 66 mK, to reveal the existence of an unusual liquid-like quantum phase in BaFe12O19, characterized by itinerant low-energy excitations with a small gap. The possible quantum liquids of electric dipoles in frustrated dielectrics open up a fresh playground for fundamental physics.

  5. Single Null Negative Triangularity Tokamak for Power Handling

    Science.gov (United States)

    Kikuchi, Mitsuru; Medvedev, S.; Takizuka, T.; Sauter, O.; Merle, A.; Coda, S.; Chen, D.; Li, J. X.

    2017-10-01

    Power and particle control in fusion reactor is challenge and we proposed the negative triangularity tokamak (NTT) to eliminate ELM by operating L-mode edge with improved core confinement. The SN configuration has more flexibility in shaping by adopting rectangular-shaped TF coils. The limiting normalized beta is 3.56 with wall stabilization and 3.14 without wall. The vertical stability is assured under a reasonable control system. The wetted area on the divertor plates becomes wider in proportion to the larger major radius at the divertor strike points due to the NT configuration. In addition to the major-radius effect, the ``Flux Tune Expansion (FTE)'' is adopted to further reduce the heat load on the divertor plate by factor of 2.6 with a coil current 3 MA. L-mode edge also allows further increase in wetted area. The fusion power of 3 GW is deliverable only at normalized beta 2.1. Therefore this reactor may be operable stably against the serious MHD activities. The CD power for SS operation is 175 MW at Q = 17. AC operation is also possible option. A required HH factor is relatively modest H = 1.12.

  6. Well-balanced positivity preserving central-upwind scheme on triangular grids for the Saint-Venant system

    KAUST Repository

    Bryson, Steve

    2010-10-11

    We introduce a new second-order central-upwind scheme for the Saint-Venant system of shallow water equations on triangular grids. We prove that the scheme both preserves "lake at rest" steady states and guarantees the positivity of the computed fluid depth. Moreover, it can be applied to models with discontinuous bottom topography and irregular channel widths. We demonstrate these features of the new scheme, as well as its high resolution and robustness in a number of numerical examples. © EDP Sciences, SMAI, 2010.

  7. Derivatives of triangular, Toeplitz, circulant matrices and matrices of other forms over semirings

    OpenAIRE

    Vladeva, Dimitrinka

    2017-01-01

    In this article we construct examples of derivations in matrix semirings. We study hereditary and inner derivations, derivatives of diagonal, triangular, Toeplitz, circulant matrices and of matrices of other forms and prove theorems for derivatives of matrices of these forms.

  8. Stress Distribution on Sandwich Structure with Triangular Grid Cores Suffered from Bending Load

    Directory of Open Access Journals (Sweden)

    Cui Xu

    2015-01-01

    Full Text Available Triangular grid reinforced by carbon fiber/epoxy (CF/EP was designed and manufactured. The sandwich structure was prepared by gluing the core and composite skins. The mechanical properties of the sandwich structure were investigated by the finite element analysis (FEA and three-point bending methods. The calculated bending stiffness and core shear stress were compared to the characteristics of a honeycomb sandwich structure. The results indicated that the triangular core ultimately failed under a bending load of 11000 N; the principal stress concentration was located at the loading region; and the cracks occurred on the interface top skin and triangular core. In addition, the ultimate stress bearing of the sandwich structure was 8828 N. The experimental results showed that the carbon fiber reinforced triangular grid was much stiffer and stronger than the honeycomb structure.

  9. Facile synthesis of microporous SiO2/triangular Ag composite nanostructures for photocatalysis

    Science.gov (United States)

    Sirohi, Sidhharth; Singh, Anandpreet; Dagar, Chakit; Saini, Gajender; Pani, Balaram; Nain, Ratyakshi

    2017-09-01

    In this article, we present a novel fabrication of microporous SiO2/triangular Ag nanoparticles for dye (methylene blue) adsorption and plasmon-mediated degradation. Microporous SiO2 nanoparticles with pore size amine groups. Amine-functionalized microporous silica was used for adsorption of triangular silver (Ag) nanoparticles. The synthesized microporous SiO2 nanostructures were investigated for adsorption of different dyes including methylene blue, congo red, direct green 26 and curcumin crystalline. Amine-functionalized microporous SiO2/triangular Ag nanostructures were used for plasmon-mediated photocatalysis of methylene blue. The experimental results revealed that the large surface area of microporous silica facilitated adsorption of dye. Triangular Ag nanoparticles, due to their better charge carrier generation and enhanced surface plasmon resonance, further enhanced the photocatalysis performance.

  10. Facile synthesis of microporous SiO2/triangular Ag composite nanostructures for photocatalysis

    Science.gov (United States)

    Sirohi, Sidhharth; Singh, Anandpreet; Dagar, Chakit; Saini, Gajender; Pani, Balaram; Nain, Ratyakshi

    2017-11-01

    In this article, we present a novel fabrication of microporous SiO2/triangular Ag nanoparticles for dye (methylene blue) adsorption and plasmon-mediated degradation. Microporous SiO2 nanoparticles with pore size silica was used for adsorption of triangular silver (Ag) nanoparticles. The synthesized microporous SiO2 nanostructures were investigated for adsorption of different dyes including methylene blue, congo red, direct green 26 and curcumin crystalline. Amine-functionalized microporous SiO2/triangular Ag nanostructures were used for plasmon-mediated photocatalysis of methylene blue. The experimental results revealed that the large surface area of microporous silica facilitated adsorption of dye. Triangular Ag nanoparticles, due to their better charge carrier generation and enhanced surface plasmon resonance, further enhanced the photocatalysis performance.

  11. Elemental matrices for the finite element method in electromagnetics with quadratic triangular elements

    OpenAIRE

    Cojocaru, E.

    2009-01-01

    The finite element method has become a preeminent simulation technique in electromagnetics. For problems involving anisotropic media and metamaterials, proper algorithms should be developed. It has been proved that discretizing in quadratic triangular elements may lead to an improved accuracy. Here we present a collection of elemental matrices evaluated analytically for quadratic triangular elements. They could be useful for the finite element method in advanced electromagnetics.

  12. Unitary Root Music and Unitary Music with Real-Valued Rank Revealing Triangular Factorization

    Science.gov (United States)

    2010-06-01

    AFRL-RY-WP-TP-2010-1213 UNITARY ROOT MUSIC AND UNITARY MUSIC WITH REAL-VALUED RANK REVEALING TRIANGULAR FACTORIZATION (Postprint) Nizar...DATES COVERED (From - To) June 2010 Journal Article Postprint 08 September 2006 – 31 August 2009 4. TITLE AND SUBTITLE UNITARY ROOT MUSIC AND...UNITARY MUSIC WITH REAL-VALUED RANK REVEALING TRIANGULAR FACTORIZATION (Postprint) 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA8650-05-D-1912-0007 5c

  13. Energy levels of double triangular graphene quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Liang, F. X.; Jiang, Z. T., E-mail: ztjiang616@hotmail.com; Zhang, H. Y.; Li, S. [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); Lv, Z. T. [School of Physics, Beijing Institute of Technology, Beijing 100081 (China); School of Physical Science and Information Engineering, Liaocheng University, Liaocheng 252059 (China)

    2014-09-28

    We investigate theoretically the energy levels of the coupled double triangular graphene quantum dots (GQDs) based on the tight-binding Hamiltonian model. The double GQDs including the ZZ-type, ZA-type, and AA-type GQDs with the two GQDs having the zigzag or armchair boundaries can be coupled together via different interdot connections, such as the direct coupling, the chains of benzene rings, and those of carbon atoms. It is shown that the energy spectrum of the coupled double GQDs is the amalgamation of those spectra of the corresponding two isolated GQDs with the modification triggered by the interdot connections. The interdot connection is inclined to lift up the degeneracies of the energy levels in different degree, and as the connection changes from the direct coupling to the long chains, the removal of energy degeneracies is suppressed in ZZ-type and AA-type double GQDs, which indicates that the two coupled GQDs are inclined to become decoupled. Then we consider the influences on the spectra of the coupled double GQDs induced by the electric fields applied on the GQDs or the connection, which manifests as the global spectrum redistribution or the local energy level shift. Finally, we study the symmetrical and asymmetrical energy spectra of the double GQDs caused by the substrates supporting the two GQDs, clearly demonstrating how the substrates affect the double GQDs' spectrum. This research elucidates the energy spectra of the coupled double GQDs, as well as the mechanics of manipulating them by the electric field and the substrates, which would be a significant reference for designing GQD-based devices.

  14. Realization of a Hole-Doped Mott Insulator on a Triangular Silicon Lattice

    Science.gov (United States)

    Ming, Fangfei; Johnston, Steve; Mulugeta, Daniel; Smith, Tyler S.; Vilmercati, Paolo; Lee, Geunseop; Maier, Thomas A.; Snijders, Paul C.; Weitering, Hanno H.

    2017-12-01

    The physics of doped Mott insulators is at the heart of some of the most exotic physical phenomena in materials research including insulator-metal transitions, colossal magnetoresistance, and high-temperature superconductivity in layered perovskite compounds. Advances in this field would greatly benefit from the availability of new material systems with a similar richness of physical phenomena but with fewer chemical and structural complications in comparison to oxides. Using scanning tunneling microscopy and spectroscopy, we show that such a system can be realized on a silicon platform. The adsorption of one-third monolayer of Sn atoms on a Si(111) surface produces a triangular surface lattice with half filled dangling bond orbitals. Modulation hole doping of these dangling bonds unveils clear hallmarks of Mott physics, such as spectral weight transfer and the formation of quasiparticle states at the Fermi level, well-defined Fermi contour segments, and a sharp singularity in the density of states. These observations are remarkably similar to those made in complex oxide materials, including high-temperature superconductors, but highly extraordinary within the realm of conventional s p -bonded semiconductor materials. It suggests that exotic quantum matter phases can be realized and engineered on silicon-based materials platforms.

  15. MR morphology of triangular fibrocartilage complex: correlation with quantitative MR and biomechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Won C.; Chang, Eric Y.; Chung, Christine B. [VA San Diego Healthcare System, Radiology Service, San Diego, CA (United States); University of California-San Diego, Department of Radiology, San Diego, CA (United States); Ruangchaijatuporn, Thumanoon [Mahidol University, Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Rachathewi, Bangkok (Thailand); Biswas, Reni; Du, Jiang; Statum, Sheronda [University of California-San Diego, Department of Radiology, San Diego, CA (United States)

    2016-04-15

    To evaluate pathology of the triangular fibrocartilage complex (TFCC) using high-resolution morphologic magnetic resonance (MR) imaging, and compare with quantitative MR and biomechanical properties. Five cadaveric wrists (22-70 years) were imaged at 3 T using morphologic (proton density weighted spin echo, PD FS, and 3D spoiled gradient echo, 3D SPGR) and quantitative MR sequences to determine T2 and T1rho properties. In eight geographic regions, morphology of TFC disc and laminae were evaluated for pathology and quantitative MR values. Samples were disarticulated and biomechanical indentation testing was performed on the distal surface of the TFC disc. On morphologic PD SE images, TFC disc pathology included degeneration and tears, while that of the laminae included degeneration, degeneration with superimposed tear, mucinous transformation, and globular calcification. Punctate calcifications were highly visible on 3D SPGR images and found only in pathologic regions. Disc pathology occurred more frequently in proximal regions of the disc than distal regions. Quantitative MR values were lowest in normal samples, and generally higher in pathologic regions. Biomechanical testing demonstrated an inverse relationship, with indentation modulus being high in normal regions with low MR values. The laminae studied were mostly pathologic, and additional normal samples are needed to discern quantitative changes. These results show technical feasibility of morphologic MR, quantitative MR, and biomechanical techniques to characterize pathology of the TFCC. Quantitative MRI may be a suitable surrogate marker of soft tissue mechanical properties, and a useful adjunct to conventional morphologic MR techniques. (orig.)

  16. Equilateral Triangular Dielectric Resonator Nantenna at Optical Frequencies for Energy Harvesting

    Directory of Open Access Journals (Sweden)

    Waleed Tariq Sethi

    2015-01-01

    Full Text Available The last decade has witnessed a remarkable growth in the telecommunication industry. With the introduction of smart gadgets, the demand for high data rate and bandwidth for wireless applications have increased exponentially at the cost of exponential consumption of energy. The latter is pushing the research and industry communities to devise green communication solutions that require the design of energy saving devices and techniques in one part and ambient energy harvesting techniques in the other part. With the advent of nanocomponents fabrication technology, researchers are now able to tap into the THz frequency regime and fabricate optical low profile antennas at a nanoscale. Optical antennas have proved their potential and are revolutionizing a class of novel optical detectors, interconnectors, sensors, and energy harvesting related fields. Authors in this paper propose an equilateral triangular dielectric resonator nantenna (ETDRNA working at 193.5 THz standard optical frequency. The simulated antenna achieves an impedance bandwidth from 192.3 THz to 197.3 THz with an end-fire directivity of 8.6 dBi, covering the entire standard optical window of C-band. Numerical demonstrations prove the efficiency of the nantenna at the frequencies of interest, making it a viable candidate for future green energy harvesting and high speed optical applications.

  17. "Switching on" the properties of single-molecule magnetism in triangular manganese(III) complexes.

    Science.gov (United States)

    Stamatatos, Theocharis C; Foguet-Albiol, Dolos; Lee, Sheng-Chiang; Stoumpos, Constantinos C; Raptopoulou, Catherine P; Terzis, Aris; Wernsdorfer, Wolfgang; Hill, Stephen O; Perlepes, Spyros P; Christou, George

    2007-08-01

    The reaction between oxide-centered, triangular [MnIII3O(O2CR)6(py)3](ClO4) (R = Me (1), Et (2), Ph (3)) compounds and methyl 2-pyridyl ketone oxime (mpkoH) affords a new family of Mn/carboxylato/oximato complexes, [MnIII3O(O2CR)3(mpko)3](ClO4) [R = Me (4), Et (5), and Ph (6)]. As in 1-3, the cations of 4-6 contain an [MnIII3(mu3-O)]7+ triangular core, but with each Mn2 edge now bridged by an eta1:eta1:mu-RCO2- and an eta1:eta1:eta1:mu-mpko- group. The tridentate binding mode of the latter causes a buckling of the formerly planar [MnIII3(mu3-O)]7+ core, resulting in a relative twisting of the three MnIII octahedra and the central O2- ion now lying approximately 0.3 A above the Mn3 plane. This structural distortion leads to ferromagnetic exchange interactions within the molecule and a resulting S = 6 ground state. Fits of dc magnetization data for 4-6 collected in the 1.8-10.0 K and 10-70 kG ranges confirmed S = 6 ground states, and gave the following D and g values: -0.34 cm(-1) and 1.92 for 4, -0.34 cm(-1) and 1.93 for 5, and -0.35 cm(-1) and 1.99 for 6, where D is the axial zero-field splitting (anisotropy) parameter. Complexes 4-6 all exhibit frequency-dependent out-of-phase (chi" M) ac susceptibility signals suggesting them possibly to be single-molecule magnets (SMMs). Relaxation rate vs T data for complex 4 down to 1.8 K obtained from the chi" M vs T studies were supplemented with rate vs T data measured to 0.04 K via magnetization vs time decay studies, and these were used to construct Arrhenius plots from which was obtained the effective barrier to relaxation (Ueff) of 10.9 K. Magnetization vs dc field sweeps on single-crystals of 4.3CH2Cl2 displayed hysteresis loops exhibiting steps due to quantum tunneling of magnetization (QTM). The loops were essentially temperature-independent below approximately 0.3 K, indicating only ground-state QTM between the lowest-lying Ms = +/-6 levels. Complexes 4-6 are thus confirmed as the first triangular SMMs. High

  18. Large area multi-channel plasmonic absorber based on the touching triangular dimers fabricated by angle controlled colloidal nanolithography

    Science.gov (United States)

    Hamidi, S. M.; Behjati, S.

    2018-02-01

    Here we introduce large area plasmonic touching triangular dimers by angle controlled colloidal nanolithography to use them as an efficient multi channel absorber and also high figure of merit sensors. For this purpose, we coated gold thin films onto nanometric and also micrometric polystyrene hexagonal closed packed masks in different deposition angles and also diverse substrate polar angles. Our prepared samples, after remove masks, show large area touching triangular pattern with different inter particle distances in greater polar angles. To get more sense about optical response of the samples such as transmittance and also electric field distribution, we use finite difference time domain method in simulation part. The transmittance plot shows one narrow or multi-channel adjustable deep depend on inter-particle distances which can be controlled by azimuthally angle in nano lithography process. Also, due to the isoelliptical points in the transmittance spectra; we can see the bright and dark plasmon modes coupling and thus the Fano like resonance takes place in the optical spectral region which is very useful for refractive index measurement.

  19. The Interval-Valued Triangular Fuzzy Soft Set and Its Method of Dynamic Decision Making

    Directory of Open Access Journals (Sweden)

    Xiaoguo Chen

    2014-01-01

    Full Text Available A concept of interval-valued triangular fuzzy soft set is presented, and some operations of “AND,” “OR,” intersection, union and complement, and so forth are defined. Then some relative properties are discussed and several conclusions are drawn. A dynamic decision making model is built based on the definition of interval-valued triangular fuzzy soft set, in which period weight is determined by the exponential decay method. The arithmetic weighted average operator of interval-valued triangular fuzzy soft set is given by the aggregating thought, thereby aggregating interval-valued triangular fuzzy soft sets of different time-series into a collective interval-valued triangular fuzzy soft set. The formulas of selection and decision values of different objects are given; therefore the optimal decision making is achieved according to the decision values. Finally, the steps of this method are concluded, and one example is given to explain the application of the method.

  20. Reuse of B-spline-based shape interrogation tools for triangular mesh models

    Science.gov (United States)

    Kobashi, Yuji; Suzuki, Junya; Joo, Han Kyul; Maekawa, Takashi

    2012-06-01

    In many engineering applications, a smooth surface is often approximated by a mesh of polygons. In a number of downstream applications, it is frequently necessary to estimate the differential invariant properties of the underlying smooth surfaces of the mesh. Such applications include first-order surface interrogation methods that entail the use of isophotes, reflection lines, and highlight lines, and second-order surface interrogation methods such as the computation of geodesics, geodesic offsets, lines of curvature, and detection of umbilics. However, we are not able to directly apply these tools that were developed for B-spline surfaces to tessellated surfaces. This article describes a unifying technique that enables us to use the shape interrogation tools developed for B-spline surface on objects represented by triangular meshes. First, the region of interest of a given triangular mesh is transformed into a graph function (z=h(x,y)) so that we can treat the triangular domain within the rectangular domain. Each triangular mesh is then converted into a cubic graph triangular Bézier patch so that the positions as well as the derivatives of the surface can be evaluated for any given point (x,y) in the domain. A number of illustrative examples are given that show the effectiveness of our algorithm. [Figure not available: see fulltext.

  1. Tunability of Triangular SRR and Wire Strip (TSRR-WS Metamaterial at THz

    Directory of Open Access Journals (Sweden)

    Parul Dawar

    2014-01-01

    Full Text Available This paper adumbrates a novel tunable metamaterial consisting of triangular split ring resonator (TSRR and wire strip (WS at THz frequency. Ansoft high frequency structure simulator (HFSS has been used to design and analyse the metamaterial having Rogers RT/duroid 5870 (εr  =  2.33 and FR4 (εr  =  4.4 as substrate material. Nicolson Ross Weir (NRW method has been used to retrieve the material parameters from transmission and reflection coefficient. 4% maximization has been obtained in the location of the negative region (or resonance frequency for permeability by using FR4 with 0.75 μm instead of 1.25 μm as substrate thickness. In addition, 18% minimization has been achieved by using FR4 with 0.25 μm instead of RT/duroid 5870 substrate with the same thickness. Tunability has been proved by showing dependence of resonant frequency over the substrate thickness and substrate material.

  2. Ordering phenomena in a heterostructure of frustrated and unfrustrated triangular-lattice Ising layers

    Science.gov (United States)

    Žukovič, Milan; Tomita, Yusuke; Kamiya, Y.

    2017-07-01

    We study critical and magnetic properties of a bilayer Ising system consisting of two triangular planes A and B, with the antiferromagnetic (AF) coupling JA and the ferromagnetic (FM) one JB for the respective layers, which are coupled by the interlayer interaction JAB by using Monte Carlo simulations. When JA and JB are of the same order, the unfrustrated FM plane orders first at a high temperature Tc 1˜JB . The spontaneous FM order then exerts influence on the other frustrated AF plane as an effective magnetic field, which subsequently induces a ferrimagnetic order in this plane at low temperatures below Tc 2. When short-range order is developed in the AF plane while the influence of the FM plane is still small, there appears a preemptive Berezinskii-Kosterlitz-Thouless-type pseudocritical crossover regime just above the ferrimagnetic phase transition point, where the short-distance behavior up to a rather large length scale exponentially diverging in ∝JA/T is controlled by a line of Gaussian fixed points at T =0 . In the crossover region, a continuous variation in the effective critical exponent 4/9 ≲ηeff≲1/2 is observed. The phase diagram by changing the ratio JA/JB is also investigated.

  3. Natural convection air flow in vertical upright-angled triangular cavities under realistic thermal boundary conditions

    Directory of Open Access Journals (Sweden)

    Sieres Jaime

    2016-01-01

    Full Text Available This paper presents an analytical and numerical computation of laminar natural convection in a collection of vertical upright-angled triangular cavities filled with air. The vertical wall is heated with a uniform heat flux; the inclined wall is cooled with a uniform temperature; while the upper horizontal wall is assumed thermally insulated. The defining aperture angle φ is located at the lower vertex between the vertical and inclined walls. The finite element method is implemented to perform the computational analysis of the conservation equations for three aperture angles φ (= 15º, 30º and 45º and height-based modified Rayleigh numbers ranging from a low Ra = 0 (pure conduction to a high 109. Numerical results are reported for the velocity and temperature fields as well as the Nusselt numbers at the heated vertical wall. The numerical computations are also focused on the determination of the value of the maximum or critical temperature along the hot vertical wall and its dependence with the modified Rayleigh number and the aperture angle.

  4. Hesitant Triangular Fuzzy Information Aggregation Operators Based on Bonferroni Means and Their Application to Multiple Attribute Decision Making

    Science.gov (United States)

    Zhou, Xiaoqiang; Yang, Tian

    2014-01-01

    We investigate the multiple attribute decision-making (MADM) problems with hesitant triangular fuzzy information. Firstly, definition and some operational laws of hesitant triangular fuzzy elements are introduced. Then, we develop some hesitant triangular fuzzy aggregation operators based on Bonferroni means and discuss their basic properties. Some existing operators can be viewed as their special cases. Next, we apply the proposed operators to deal with multiple attribute decision-making problems under hesitant triangular fuzzy environment. Finally, an illustrative example is given to show the developed method and demonstrate its practicality and effectiveness. PMID:25140338

  5. A PSO-based approach to optimize the triangular membership functions in a fuzzy logic controller

    Science.gov (United States)

    Maniscalco, Vincenzo; Lombardo, Francesco

    2017-11-01

    In this paper a Particle Swarm Optimization (PSO) algorithm is considered in order to optimize the triangular Membership Functions (MF) in a Fuzzy Logic Controller (FLC). PSO algorithm belongs to the class of Swarm Intelligence (SI) techniques and is considered an efficient heuristic technique for optimization problem in a continuous and multidimen-sional search spaces. Performance of a FLC depends on the fuzzy partition of each input/output space considered and the PSO algorithm can be used to obtain the optimal or near optimal parameters of the triangular membership functions in order to achieve the best results in the defuzzification process. Simulation results obtained by this approach to tune the triangular membership functions of a FLC for an application concerning the optimization of the energy consumption in Industrial Wireless Sensor Networks (IWSN) are reported.

  6. Study on the Optical Properties of Triangular Cavity Absorber for Parabolic Trough Solar Concentrator

    Directory of Open Access Journals (Sweden)

    Fei Chen

    2015-01-01

    Full Text Available A theoretical analytical method for optical properties of cavity absorber was proposed in this paper and the optical design software TracePro was used to analyze the optical properties of triangular cavity absorber. It was found that the optimal optical properties could be achieved with appropriate aperture width, depth-to-width ratio, and offset distance from focus of triangular cavity absorber. Based on the results of orthogonal experiment, the optimized triangular cavity absorber was designed. Results showed that the standard deviation of irradiance and optical efficiency of optimized designed cavity absorber were 30528 W/m2 and 89.23%, respectively. Therefore, this study could offer some valuable references for designing the parabolic trough solar concentrator in the future.

  7. Pedestal properties of H-modes with negative triangularity using the EPED-CH model

    Science.gov (United States)

    Merle, A.; Sauter, O.; Medvedev, S. Yu

    2017-10-01

    The EPED model has been designed to predict the pedestal height and width from a minimal set of parameters and using the stability of the pedestal region for global MHD peeling-ballooning (P-B) modes as well as local kinetic ballooning modes (KBMs). This approach has been validated for type-I ELMy H-modes and quiescent H-modes (QH) but can also be used for other types of H-modes where it usually sets an upper limit on the achievable pedestal height. Using the recently developed EPED-like model called EPED-CH and based on the equilibrium codes CHEASE and CAXE and the MHD stability code KINX, we investigate in this work the effect of negative triangularity on the pedestal structure. Our simulation results confirm the experimental results from TCV where a reduction of the pedestal height was observed when going from positive to negative top triangularity. This was interpreted as a degradation of the peeling-ballooning stability due to the closed access to the second stability region for ballooning modes in the case of negative triangularity. This effect is further enhanced by the coupling to the KBM stability criterion in EPED simulations. The novel concept of the negative triangularity tokamak (a DEMO-sized machine) is also investigated. Again a strong reduction of the pedestal height and width is observed going from positive to negative triangularity for up-down symmetric equilibria. The pedestal height is also reduced going to more up-down asymmetric cases. The beneficial effect of the global β value on the pedestal height, which is linked to the second stability access, is strongly reduced for negative triangularity.

  8. Effects of Shannon entropy and electric field on polaron in RbCl triangular quantum dot

    Science.gov (United States)

    M, Tiotsop; A, J. Fotue; S, C. Kenfack; N, Issofa; H, Fotsin; L, C. Fai

    2016-04-01

    In this paper, the time evolution of the quantum mechanical state of a polaron is examined using the Pekar type variational method on the condition of the electric-LO-phonon strong-coupling and polar angle in RbCl triangular quantum dot. We obtain the eigenenergies, and the eigenfunctions of the ground state, and the first excited state respectively. This system in a quantum dot can be treated as a two-level quantum system qubit and the numerical calculations are performed. The effects of Shannon entropy and electric field on the polaron in the RbCl triangular quantum dot are also studied.

  9. Enhanced Light Extraction From Triangular GaN-Based Light-Emitting Diodes

    OpenAIRE

    Kim, J. Y.; M. K. Kwon; Kim, J P; Park, S J

    2007-01-01

    This study investigated the characteristics of a triangular light-emitting diode (LED) and compared it to a standard quadrangular LED. The total radiant flux from the packaged triangular LED increased by 48% and 24% at input currents of 20 and 100 mA, respectively, compared to that of a quadrangular LED which was grown on patterned sapphire substrate. In light far-field beam distribution, the light extraction in the horizontal direction of the LED was much higher than that of the quadrangular...

  10. Interacción de agregados de cromo con nanografenos triangulares

    OpenAIRE

    Calleja Rebanal, Ángela

    2012-01-01

    El objetivo de este trabajo es estudiar la interacción de compuestos de cromo con estructuras de grafeno (capa de átomos de carbono de un átomo de espesor dispuestos en una retícula de tipo hexagonal) triangular con bordes de tipo zig-zag, prestando especial atención a las propiedades magnéticas de estos sistemas. También se realizará una comparación con la lámina y el agregado libres, estudiando como varían sus propiedades. Para ello, se tomarán dos estructuras triangulares de...

  11. Triangular Energy-Saving Cache-Based Routing Protocol by Energy Sieving

    OpenAIRE

    Chiu-Ching Tuan; Yi-Chao Wu

    2012-01-01

    In wireless ad hoc networks, designing an energy-efficient routing protocol is a major issue since nodes are energy limited. To address energy issue, we proposed a triangular energy-saving cached-based routing protocol by energy sieving (TESCES). TESCES offered a grid leader election by energy sieving (GLEES), a cache-based grid leader maintenance (CGLM), and a triangular energy-saving routing discovery (TESRD). In GLEES, only few nodes join in grid leader election to be elected as a grid lea...

  12. Efficient Linear and Non-Linear Finite Element Formulation using a New Local Enhancement of Displacement Fields for Triangular Elements

    DEFF Research Database (Denmark)

    Damkilde, Lars; Pedersen, Ronnie

    2012-01-01

    This paper describes a new triangular plane element which can be considered as a linear strain triangular element (LST) extended with incompatible displacement modes. The extended element will have a full cubic interpolation of strains and stresses. The extended LST-element is connected with othe...

  13. Characterization of Obtuse Triangular Defects on 4H-SiC 4° off-Axis Epitaxial Wafers

    Science.gov (United States)

    Dong, Lin; Sun, Guo-Sheng; Yu, Jun; Zheng, Liu; Liu, Xing-Fang; Zhang, Feng; Yan, Guo-Guo; Li, Xi-Guang; Wang, Zhan-Guo; Yang, Fei

    2013-09-01

    We investigate the triangular defects with different structural features on 4H-SiC epilayers by a Nomarski microscope, a Candela optical surface analyzer and ultraviolet photoluminescence (UV-PL) imaging. Both the foreign particles and the substrate scratches can cause the formation of the obtuse triangular defects. The central area of some obtuse triangular defects can have the spatially confined core, in which the in-grown stacking faults can be observed under the UV-PL imaging. In contrast, the obtuse triangular defects induced by the scratches appear in the form of band-like defects, of which the width depends on the scratch direction and reaches the maximum when the scratch direction is parallel to the step flow direction. The formation mechanisms of these obtuse triangular defects are discussed.

  14. Notes on TQFT wire models and coherence equations for SU(3) triangular cells

    CERN Document Server

    Coquereaux, R; Schieber, G

    2010-01-01

    After a summary of the TQFT wire model formalism we bridge the gap from Kuperberg equations for SU(3) spiders to Ocneanu coherence equations for systems of triangular cells on fusion graphs that describe modules associated with the fusion category of SU(3) at level k. We show how to solve these equations in a number of examples.

  15. New triangular mass-lumped finite elements of degree six for wave propagation

    NARCIS (Netherlands)

    Mulder, W.A.

    2013-01-01

    Mass-lumped continuous finite elements allow for explicit time stepping with the second-order wave equation if the resulting integration weights are positive and provide sufficient accuracy. To meet these requirements on triangular and tetrahedral meshes, the construction of continuous finite

  16. Indirect RIXS study of bimagnon excitations in triangular-lattice quantum Heisenberg antiferromagnet

    Science.gov (United States)

    Datta, Trinanjan; Luo, Cheng; Huang, Zengye; Yao, Dao-Xin

    2015-03-01

    Bimagnon correlations in triangular-lattice quantum Heisenberg antiferromagnet can be probed by the resonant inelastic X-ray scattering (RIXS) technique. Utilizing an interacting spin wave theory within the Bethe-Salpeter approximation scheme, we compute the K-edge indirect RIXS spectra for the nearest neighbor Heisenberg model with a general S for the entire magnetic brillouin zone. The non-collinear spin arrangement in the triangular lattice geometry supports the intrinsic spontaneous single-magnon decay or recombination. Based on our calculation, we find that the RIXS spectra display a peak at the antiferromagnetic wave vector (4 π / 3 , 0) corresponding to the triangular lattice, which is in contrast to the square lattice case. The major contribution to the RIXS spectra originates from the decay vertices arising from the three-magnon interaction terms, with the quartic interaction contributions subdued. Our results indicate that the spontaneous decay and recombination of magnons inherent to the triangular lattice model can be oberved in the RIXS spectra without a disintegration. GRU Small Grants Program, NBRPC-2012CB821400,NSFC-11275279.

  17. Subspace-Based Noise Reduction for Speech Signals via Diagonal and Triangular Matrix Decompositions

    DEFF Research Database (Denmark)

    Hansen, Per Christian; Jensen, Søren Holdt

    2007-01-01

    diagonal (eigenvalue and singular value) decompositions and rank-revealing triangular decompositions (ULV, URV, VSV, ULLV and ULLIV). In addition we show how the subspace-based algorithms can be evaluated and compared by means of simple FIR filter interpretations. The algorithms are illustrated...

  18. Continuous weakly cancellative triangular subnorms: I. Their web-geometric properties

    Czech Academy of Sciences Publication Activity Database

    Petrík, Milan; Sarkoci, Peter

    2018-01-01

    Roč. 332, 1 February (2018), s. 93-110 ISSN 0165-0114 R&D Projects: GA ČR GJ15-07724Y Institutional support: RVO:67985807 Keywords : associativity * conditionally cancellative * continuous triangular subnorm * contour * level set * Reidemeister closure condition * weakly cancellative * web geometry Subject RIV: BA - General Mathematics Impact factor: 2.718, year: 2016

  19. Theoretical study of two-element array of equilateral triangular patch ...

    Indian Academy of Sciences (India)

    The radiation characteristics of a two-element array of equilateral triangular patch microstrip antenna on a ferrite substrate are studied theoretically by considering the presence of bias magnetic field in the direction of propagation of electromagnetic waves. It is found that the natural modes of propagation in the direction of ...

  20. A New Accurate yet Simple Shear Flexible Triangular Plate Element with Linear Bending Strains

    DEFF Research Database (Denmark)

    Damkilde, Lars; Pedersen, Ronnie

    2010-01-01

    The paper describes a new shear flexible triangular element. The formulation is based on displacement interpolation of the transverse displacement of the midsurface and the rotations of the cross-sections, and the element is fully compatible. The basic principle is to use a so-called balanced int...

  1. Half-magnetization plateau in a Heisenberg antiferromagnet on a triangular lattice

    Science.gov (United States)

    Ye, Mengxing; Chubukov, Andrey V.

    2017-10-01

    We present the phase diagram of a 2D isotropic triangular Heisenberg antiferromagnet in a magnetic field. We consider spin-S model with nearest-neighbor (J1) and next-nearest-neighbor (J2) interactions. We focus on the range of 1 /8 border the "three up, one down" state and discuss the transitions between these states and the canted stripe state.

  2. Air-guiding photonic bandgap fiber with improved triangular air-silica photonic crystal cladding

    OpenAIRE

    Yan, M.; Shum, P

    2005-01-01

    We introduce a small-core air-guiding photonic crystal fiber whose cladding is made of improved air-silica photonic crystal with non-circular air holes placed in triangular lattice. The fiber achieves un-disturbed bandgap guidance over 350nm wavelength range.

  3. Robust band gap and half-metallicity in graphene with triangular perforations

    DEFF Research Database (Denmark)

    Gregersen, Søren Schou; Power, Stephen; Jauho, Antti-Pekka

    2016-01-01

    . The inclusion of spin polarization within a mean-field Hubbard approach gives rise to a large overall magnetic moment at each antidot due to the sublattice imbalance imposed by the triangular geometry. Half-metallic behavior arises from the formation of spin-split dispersive states near the Fermi energy...

  4. 26 CFR 1.358-6 - Stock basis in certain triangular reorganizations.

    Science.gov (United States)

    2010-04-01

    ... acquisition by S of T stock in exchange for P stock in a transaction that qualifies as a reorganization under... (c)(2), P's basis in its T stock acquired in a reverse triangular merger equals its basis in its S... $5 cash (which S retains), and T merges into S. In the merger, the T shareholders receive P stock...

  5. Synthesis of circular and triangular gold nanorings with tunable optical properties

    KAUST Repository

    Lin, Xiaoying

    2017-08-24

    This communication describes a robust wet-chemical synthetic strategy for the preparation of monodispersed circular and triangular gold nanorings. The localized surface plasmon resonance of the nanorings can be tuned by controlling the outer diameter and ridge thickness of the nanorings.

  6. Breaking away from the Pack: Positioning the Marketing Discipline through a Triangular Analysis.

    Science.gov (United States)

    Bonnici, Joseph L.; Reddy, Allan C.

    1993-01-01

    College and university marketing departments should use the technique of positioning to increase enrollments. The triangular approach to positioning uses close scrutiny of the student profile, the benefits marketing courses offer, and the competition the department faces within and outside the business school. The technique can also be used by…

  7. Electronic structure of triangular, hexagonal and round graphene flakes near the Fermi level

    Energy Technology Data Exchange (ETDEWEB)

    Heiskanen, H P; Manninen, M; Akola, J [Nanoscience Center, Department of Physics, PO Box 35, FI-40014 University of Jyvaeskylae (Finland)], E-mail: matti.manninen@jyu.fi

    2008-10-15

    The electronic shell structure of triangular, hexagonal and round graphene quantum dots (flakes) near the Fermi level has been studied using a tight-binding method. The results show that close to the Fermi level the shell structure of a triangular flake is that of free massless particles, and that triangles with an armchair edge show an additional sequence of levels ('ghost states'). These levels result from the graphene band structure and the plane wave solution of the wave equation, and they are absent for triangles with a zigzag edge. All zigzag triangles exhibit a prominent edge state at {epsilon}{sub F}, and few low-energy conduction electron states occur both in triangular and hexagonal flakes due to symmetry reasons. Armchair triangles can be used as building blocks for other types of flakes that support the ghost states. Edge roughness has only a small effect on the level structure of the triangular flakes, but the effect is considerably enhanced in the other types of flakes. In round flakes, the states near the Fermi level depend strongly on the flake radius, and they are always localized on the zigzag parts of the edge.

  8. Rare-Earth Triangular Lattice Spin Liquid: A Single-Crystal Study of YbMgGaO4.

    Science.gov (United States)

    Li, Yuesheng; Chen, Gang; Tong, Wei; Pi, Li; Liu, Juanjuan; Yang, Zhaorong; Wang, Xiaoqun; Zhang, Qingming

    2015-10-16

    YbMgGaO4, a structurally perfect two-dimensional triangular lattice with an odd number of electrons per unit cell and spin-orbit entangled effective spin-1/2 local moments for the Yb(3+) ions, is likely to experimentally realize the quantum spin liquid ground state. We report the first experimental characterization of single-crystal YbMgGaO4 samples. Because of the spin-orbit entanglement, the interaction between the neighboring Yb(3+) moments depends on the bond orientations and is highly anisotropic in the spin space. We carry out thermodynamic and the electron spin resonance measurements to confirm the anisotropic nature of the spin interaction as well as to quantitatively determine the couplings. Our result is a first step towards the theoretical understanding of the possible quantum spin liquid ground state in this system and sheds new light on the search for quantum spin liquids in strong spin-orbit coupled insulators.

  9. Floating-zone growth and characterization of triangular lattice antiferromagnetic α-SrCr2O4 crystals

    Science.gov (United States)

    Zhao, Li; Wang, Kuen-Jen; Wen, Min-Hsueh; Wu, Maw-Kuen

    2014-04-01

    The triangular S=3/2 antiferromagnetic α-phase MCr2O4 (M=Ca, Sr, Ba) family has received increasing attention for their low dimensional geometrically frustrated magnetism. For the first time, the single crystals of α-SrCr2O4 were successfully grown by the floating-zone method. The plate-like crystals are highly a-axis oriented with a 60° twinning structure in the bc plane. We also investigated the magnetic susceptibilities, specific heat and dielectric properties systematically. Our results confirm a long range magnetic ordering emerging in α-SrCr2O4 below about 43 K. These crystals are suitable for the future neutron scattering experiments and other in-depth physical measurements.

  10. Structure and Reversibility of 2D von Neumann Cellular Automata Over Triangular Lattice

    Science.gov (United States)

    Uguz, Selman; Redjepov, Shovkat; Acar, Ecem; Akin, Hasan

    2017-06-01

    Even though the fundamental main structure of cellular automata (CA) is a discrete special model, the global behaviors at many iterative times and on big scales could be a close, nearly a continuous, model system. CA theory is a very rich and useful phenomena of dynamical model that focuses on the local information being relayed to the neighboring cells to produce CA global behaviors. The mathematical points of the basic model imply the computable values of the mathematical structure of CA. After modeling the CA structure, an important problem is to be able to move forwards and backwards on CA to understand their behaviors in more elegant ways. A possible case is when CA is to be a reversible one. In this paper, we investigate the structure and the reversibility of two-dimensional (2D) finite, linear, triangular von Neumann CA with null boundary case. It is considered on ternary field ℤ3 (i.e. 3-state). We obtain their transition rule matrices for each special case. For given special triangular information (transition) rule matrices, we prove which triangular linear 2D von Neumann CAs are reversible or not. It is known that the reversibility cases of 2D CA are generally a much challenged problem. In the present study, the reversibility problem of 2D triangular, linear von Neumann CA with null boundary is resolved completely over ternary field. As far as we know, there is no structure and reversibility study of von Neumann 2D linear CA on triangular lattice in the literature. Due to the main CA structures being sufficiently simple to investigate in mathematical ways, and also very complex to obtain in chaotic systems, it is believed that the present construction can be applied to many areas related to these CA using any other transition rules.

  11. Triangular facets of slope in the region of Tudela (Ebro Basin, Navarra, Spain); Facetas triangulares de ladera en la region de Tudela (Depresion del Ebro, Navarra, Espana)

    Energy Technology Data Exchange (ETDEWEB)

    Marin, C.; Desir, G.; Gutierrez, M.

    2009-07-01

    Some triangular slope facets are localized to the south of Bardenas Reales (central-west of Ebro Basin), elaborated on Tudela Formation deposits, Aragonian in age. Three of them have been dated by OSL resulting on ages of 35,588{+-}2,488 yr. BP, 35,355{+-}2,446 yr. BP and 40.185{+-}2,411 yr. BP. The origin of these facets is ought to an alternation between accumulation and incision phases produced by vegetation cover variation percentage. Those vegetation cover changes are estimated to be due to climatic changes. (Author) 21 refs.

  12. Neutron diffraction reveals the existence of confined water in triangular and hexagonal channels of modified YPO4 at elevated temperatures

    Science.gov (United States)

    Mishra, S. K.; Ningthoujam, R. S.; Mittal, R.; Vatsa, R. K.; Zbiri, M.; Sharma, K. Shitaljit; Singh, B. P.; Sastry, P. U.; Hansen, T.; Schober, H.; Chaplot, S. L.

    2017-09-01

    We provide experimental evidence for confinement of water molecules in the pores of hexagonal structure of YPO4 at elevated temperatures up to 600 K using powder neutron diffraction. In order to avoid the large incoherent scattering from the hydrogen, deuterated samples of doped YPO4:Ce-Eu were used for diffraction measurements. The presence of water molecules in the triangular and hexagonal pores in the hexagonal structure was established by detailed simulation of the diffraction pattern and Rietveld refinement of the experimental data. It was observed that the presence of water leads specifically to suppression of the intensity of a peak around Q = 1.04 Å-1 while the intensity of peaks around Q = 1.83 Å-1 is enhanced in the neutron-diffraction pattern. We estimate the number of water molecules as 2.36 (6) per formula units at 300 K and the sizes of the hexagonal and triangular pores as 7.2 (1) and 4.5 (1) Å, respectively. With an increase in temperature, the water content in both pores decreases above 450 K and vanishes around 600 K. Analysis of the powder-diffraction data reveals that the hexagonal structure with the pores persist up to 1273 K, and transforms to another structure at 1323 K. The high-temperature phase is not found to have the zircon- or monazite-type structure, but a monoclinic structure (space group P 2 /m ) with lattice parameters am= 6.826 (4 ) Å ,bm= 6.645 (4 ) Å ,cm= 10.435 (9 ) Å , and β = 107.21 (6) ∘ . The monoclinic structure has about 14% smaller volume than the hexagonal structure which essentially reflects the collapse of the pores. The phase transition and the change in the volume are also confirmed by x-ray-diffraction measurements. The hexagonal-to-monoclinic phase transition is found to be irreversible on cooling to room temperature.

  13. Flexible and transparent nanogenerators based on a composite of lead-free ZnSnO3 triangular-belts.

    Science.gov (United States)

    Wu, Jyh Ming; Xu, Chen; Zhang, Yan; Yang, Ya; Zhou, Yusheng; Wang, Zhong Lin

    2012-11-27

    A flexible and transparent lead-free triangular-belt ZnSnO(3) nanogenerator is demonstrated. When a mechanical deformation of ≈0.1% is applied to the triangular-belt ZnSnO(3) nanogenerator, the output voltage and current reached 5.3 V and 0.13 μA, respectively, which indicated a maximum output power density of ≈11 μW·cm(-3). This is the highest output power that has been demonstrated by lead-free ZnSnO(3) triangular-belts. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Single Domain Magnetic Helicity and Triangular Chirality in Structurally Enantiopure Ba3NbFe3Si2O14

    Science.gov (United States)

    Marty, K.; Simonet, V.; Ressouche, E.; Ballou, R.; Lejay, P.; Bordet, P.

    2008-12-01

    A novel doubly chiral magnetic order is found in the structurally chiral langasite compound Ba3NbFe3Si2O14. The magnetic moments are distributed over planar frustrated triangular lattices of triangle units. On each of these they form the same triangular configuration. This ferrochiral arrangement is helically modulated from plane to plane. Unpolarized neutron scattering on a single crystal associated with spherical neutron polarimetry proved that a single triangular chirality together with a single helicity is stabilized in an enantiopure crystal. A mean-field analysis allows us to discern the relevance on this selection of a twist in the plane to plane super-superexchange paths.

  15. Comparative study on triangular and quadrilateral meshes by a finite-volume method with a central difference scheme

    KAUST Repository

    Yu, Guojun

    2012-10-01

    In this article, comparative studies on computational accuracies and convergence rates of triangular and quadrilateral meshes are carried out in the frame work of the finite-volume method. By theoretical analysis, we conclude that the number of triangular cells needs to be 4/3 times that of quadrilateral cells to obtain similar accuracy. The conclusion is verified by a number of numerical examples. In addition, the convergence rates of the triangular meshes are found to be slower than those of the quadrilateral meshes when the same accuracy is obtained with these two mesh types. © 2012 Taylor and Francis Group, LLC.

  16. Representation and Reconstruction of Triangular Irregular Networks with Vertical Walls

    NARCIS (Netherlands)

    Gorte, B.G.H.; Lesparre, J.

    2012-01-01

    Point clouds obtained by aerial laser scanning are a convenient input source for high resolution 2.5d elevation models, such as the Dutch AHN-2. More challenging is the fully automatic reconstruction of 3d city models. An actual demand for a combined 2.5d terrain and 3d city model for an urban

  17. A waveless free surface flow past a submerged triangular obstacle in presence of surface tension

    Directory of Open Access Journals (Sweden)

    Hakima Sekhri

    2016-07-01

    Full Text Available We consider the Free surface flows passing a submerged triangular obstacle at the bottom of a channel. The problem is characterized by a nonlinear boundary condition on the surface of unknown configuration. The analytical exact solutions for these problems are not known. Following Dias and Vanden Broeck [6], we computed numerically the solutions via a series truncation method. These solutions depend on two parameters: the Weber number $\\alpha$ characterizing the strength of the surface tension and the angle $\\beta$ at the base characterizing the shape of the apex. Although free surface flows with surface tension admit capillary waves, it is found that solution exist only for values of the Weber number greater than $\\alpha_0$ for different configurations of the triangular obstacle.

  18. Er:YAG triangular ring laser resonantly pumped by a 1470-nm laser diode

    Science.gov (United States)

    Wang, Shuo; Gao, Chunqing; Shi, Yang; Ye, Qing; Wang, Qing

    2018-01-01

    An Er:YAG triangular ring laser resonantly pumped by a 1470 nm laser diode was reported. 7.28 W continuous-wave output power at 1645 nm was obtained by using a triangular ring resonator. In the Q-switched mode, the Er:YAG laser generated pulse energies from 6.05 mJ to 16.6 mJ at 1645 nm when pulse repetition rates change from 1 kHz to 200 Hz. By inserting an etalon into the resonator, the Er:YAG laser yielded Q-switched energies from 1.714 mJ to 5.1 mJ at 1617 nm when pulse repetition rates change from 1 kHz to 200 Hz.

  19. Linear-phase approximation in the triangular facet near-field physical optics computer program

    Science.gov (United States)

    Imbriale, W. A.; Hodges, R. E.

    1990-01-01

    Analyses of reflector antenna surfaces use a computer program based on a discrete approximation of the radiation integral. The calculation replaces the actual surface with a triangular facet representation; the physical optics current is assumed to be constant over each facet. Described here is a method of calculation using linear-phase approximation of the surface currents of parabolas, ellipses, and shaped subreflectors and compares results with a previous program that used a constant-phase approximation of the triangular facets. The results show that the linear-phase approximation is a significant improvement over the constant-phase approximation, and enables computation of 100 to 1,000 lambda reflectors within a reasonable time on a Cray computer.

  20. Suture welding for arthroscopic repair of peripheral triangular fibrocartilage complex tears.

    Science.gov (United States)

    Badia, Alejandro; Khanchandani, Prakash

    2007-03-01

    This report presents a method of arthroscopic repair of the peripheral triangular fibrocartilage tears by using ultrasonic suture welding technique, thus avoiding the need for traditional suture knots. This technique eliminates the potential causes of ulnar-sided wrist discomfort especially during the postoperative period. Twenty-three patients (9 women and 14 men; mean age, 35 years; range, 18-52 years) were operated during a 1-year period in 2001 for Palmer grade 1B triangular fibrocartilage complex tear and followed up for 17 months. At the final follow-up, the average wrist arc of motion was as follows: extension, 65 degrees; flexion, 56 degrees; supination, 80 degrees; pronation, 78 degrees; radial deviation, 12 degrees; and ulnar deviation, 25 degrees. Grip strength measured with a dynamometer (Jamar) averaged 81% of the contralateral side at the final evaluation (range, 53%-105%).

  1. Surface enhanced Raman scattering, antibacterial and antifungal active triangular gold nanoparticles

    Science.gov (United States)

    Smitha, S. L.; Gopchandran, K. G.

    2013-02-01

    Shape controlled syntheses of gold nanoparticles have attracted a great deal of attention as their optical, electronic, magnetic and biological properties are strongly dependent on the size and shape of the particles. Here is a report on the surface enhanced Raman scattering (SERS) activity of Cinnamomum zeylanicum leaf broth reduced gold nanoparticles consisting of triangular and spherical like particles, using 2-aminothiophenol (2-ATP) and crystal violet (CV) as probe molecules. Nanoparticles prepared with a minimum leaf broth concentration, having a greater number of triangular like particles exhibit a SERS activity of the order of 107. The synthesized nanoparticles exhibit efficient antibacterial activity against the tested gram negative bacterium Escherichia coli and gram positive bacterium Staphylococcus aureus. Investigations on the antifungal activity of the synthesized nanoparticles against Aspergillus niger and Fusarium oxysporum positive is also discussed.

  2. Engineering Ising-XY spin-models in a triangular lattice using tunable artificial gauge fields

    Science.gov (United States)

    Struck, J.; Weinberg, M.; Ölschläger, C.; Windpassinger, P.; Simonet, J.; Sengstock, K.; Höppner, R.; Hauke, P.; Eckardt, A.; Lewenstein, M.; Mathey, L.

    2013-11-01

    Magnetism plays a key role in modern science and technology, but still many open questions arise from the interplay of magnetic many-body interactions. Deeper insight into complex magnetic behaviour and the nature of magnetic phase transitions can be obtained from, for example, model systems of coupled XY and Ising spins. Here, we report on the experimental realization of such a coupled system with ultracold atoms in triangular optical lattices. This is accomplished by imposing an artificial gauge field on the neutral atoms, which acts on them as a magnetic field does on charged particles. As a result, the atoms show persistent circular currents, the direction of which provides an Ising variable. On this, the tunable staggered gauge field, generated by a periodic driving of the lattice, acts as a longitudinal field. Further, the superfluid ground state presents strong analogies with the paradigm example of the fully frustrated XY model on a triangular lattice.

  3. Measured and predicted root-mean-square errors in square and triangular antenna mesh facets

    Science.gov (United States)

    Fichter, W. B.

    1989-01-01

    Deflection shapes of square and equilateral triangular facets of two tricot-knit, gold plated molybdenum wire mesh antenna materials were measured and compared, on the basis of root mean square (rms) differences, with deflection shapes predicted by linear membrane theory, for several cases of biaxial mesh tension. The two mesh materials contained approximately 10 and 16 holes per linear inch, measured diagonally with respect to the course and wale directions. The deflection measurement system employed a non-contact eddy current proximity probe and an electromagnetic distance sensing probe in conjunction with a precision optical level. Despite experimental uncertainties, rms differences between measured and predicted deflection shapes suggest the following conclusions: that replacing flat antenna facets with facets conforming to parabolically curved structural members yields smaller rms surface error; that potential accuracy gains are greater for equilateral triangular facets than for square facets; and that linear membrane theory can be a useful tool in the design of tricot knit wire mesh antennas.

  4. Linear and nonlinear intersubband optical properties in a triangular quantum ring

    Science.gov (United States)

    Nasri, Djillali; Bettahar, N.

    2015-12-01

    Using the effective mass approximation, within the plane wave expansion, the linear and nonlinear coefficients absorption and the refractive index changes relative to the intersubband transitions in the conduction band of an AlxGa1-xAs/ GaAs/AlxGa1-xAs triangular quantum ring for an x-polarization and an y-polarization of the incident light are calculated. It is found that the transition energy between the ground state and the first two excited states and their related optical matrix are strongly influenced by the length of the side of the inner triangle, leading to a red-shift and blue-shift of the resonant peaks of the intersubband optical absorption, for an x-polarized light absorption and an y-polarized light absorption respectively. Our results are qualitatively similar to those of a triangular quantum wire in the presence of an intense laser field in recent literature.

  5. Edge structures and properties of triangular antidots in single-layer MoS2

    KAUST Repository

    Gan, Li Yong

    2016-08-30

    Density functional theory and experiments are employed to shed light on the edge structures of antidots in O etched single-layer MoS2. The equilibrium morphology is found to be the zigzag Mo edge with each Mo atom bonded to two O atoms, in a wide range of O chemical potentials. Scanning electron microscopy shows that the orientation of the created triangular antidots is opposite to the triangular shape of the single-layer MoS2 samples, in agreement with the theoretical predictions. Furthermore, edges induced by O etching turn out to be p-doped, suggesting an effective strategy to realize p-type MoS2 devices. Published by AIP Publishing.

  6. Triangular Form of Chaotic System and its Application in Chaos Synchronization

    Science.gov (United States)

    Wang, Xing-Yuan; Gu, Ni-Ni; Zhang, Zhen-Feng

    The triangular form of a chaotic system and how to obtain it from the Lie derivative are introduced. Based on this, both the synchronization of Genesio-Tesi and Coullet systems and the generalized synchronization of Lü and Sprott-B systems are realized in two feedback ways through designing nonlinear controllers. Results of numerical simulations in MATLAB validate the effectiveness of the given synchronization methods further.

  7. A locking-free nonconforming triangular element for planar elasticity with pure traction boundary condition

    Science.gov (United States)

    Yang, Yongqin; Chen, Shaochun

    2010-03-01

    A new nonconforming triangular element for the equations of planar linear elasticity with pure traction boundary conditions is considered. By virtue of construction of the element, the discrete version of Korn's second inequality is directly proved to be valid. Convergence rate of the finite element methods is uniformly optimal with respect to [lambda]. Error estimates in the energy norm and L2-norm are O(h2) and O(h3), respectively.

  8. On the Sum of Corresponding Factorials and Triangular Numbers: Some Preliminary Results

    Directory of Open Access Journals (Sweden)

    Romer C. Castillo

    2015-11-01

    Full Text Available A new sequence of natural numbers can be formed by adding corresponding factorials and triangular numbers. In this paper, such numbers were named factoriangular numbers. Mathematical experimentations on these numbers resulted to the establishment of some of its characteristics. These include the parity, compositeness, the number and sum of its positive divisors, abundancy and deficiency, Zeckendorf’s decomposition, end digits, and digital roots of factoriangular numbers. Several theorems and corollaries were proven and some conjectures were also presented.

  9. Stacking illumination of a confocal reflector light emitting diode automobile headlamp with an asymmetric triangular prism.

    Science.gov (United States)

    Chen, Hsi-Chao; Zhou, Jia-Hao; Zhou, Yang

    2017-02-01

    A confocal reflector lamp with an asymmetric triangular prism was designed for a stacking illumination of a light emitting diode (LED) automobile headlamp fitting ECE R112 asymmetrical regulation. The optical system includes three 1st elliptic reflectors, three 2nd parabolic reflectors, and one asymmetric triangular prism. Three elliptic and parabolic reflectors were assembled with three confocal reflector modules; two modules projected the cut-off line of a 0° angle, and the other module projected the cut-off line of a 15° angle using of an asymmetric triangular prism. The ray tracing, optical simulation, and mockup experiment results exhibited that the illumination distribution met the regulation of ECE R112 class B, and the ideal efficiency could reach 96.8% in theory. The tolerance analysis showed the efficiency remained above 98% under the error values of ±0.2  mm of the position of the LED light source, and the y direction of the up-down movement was more sensitive than the x and z directions. The measurement results of the mockup sample safety factor were all larger than 1.15 and supported the regulation of the ECE R112 Class B.

  10. Electrowetting actuated microfluidic transport in surface grooves with triangular cross section.

    Science.gov (United States)

    Barman, Jitesh; Swain, Digendranath; Law, Bruce M; Seemann, Ralf; Herminghaus, Stephan; Khare, Krishnacharya

    2015-01-27

    Liquids show different static wetting morphologies in open triangular grooves depending upon the wedge angle (ψ) of the groove and the liquid contact angle (θ) with the substrate. Switching between different morphologies can be achieved either by varying the contact angle of the liquid or by changing the wedge angle of the groove. In the present work we manipulate the apparent contact angle of a liquid by electrowetting to switch between liquid morphologies, from droplet to filament, to achieve microfluidic transport of the liquid into open triangular grooves. The static length of liquid filaments in grooves is analyzed as a function of applied voltage for different applied ac frequencies. The dynamic advancement of the filament lengths in grooves is analyzed as a function of time for different applied voltages for two different liquids: first with contact angle greater than the wedge angle and second with contact angle smaller than the wedge angle. Later an exact electrical model is derived to explain the liquid transport in triangular grooves actuated by electrowetting which includes the precise geometry of the liquid morphology.

  11. Effect of Triangular Fins on Critical Heat Flux in Ethanol-cooled Combustion Chamber

    Science.gov (United States)

    Takegoshi, Masao; Suzuki, Ryosuke; Saito, Toshihito; Ono, Fumiei; Hiraiwa, Tetsuo; Tomioka, Sadatake

    A pressure-fed engine with a regeneratively-cooled combustion chamber is studied in JAXA. Operation chamber pressure is approximately 1 MPa. A proposed propellant combination is liquid oxygen and ethanol. However, it is necessary to understand the critical heat flux when ethanol is used as a coolant for regeneratively-cooled combustion chamber because the saturation pressure of it is 6.3 MPa. In general, it is known that the cooling wall with fins improves the cooling performance. In this study, the effect of triangular fins on critical heat flux of ethanol in ethanol-cooled combustion chamber was investigated. As the result, it was found that the critical heat flux of cooling wall with triangular fins was 23 % higher than that of that without fin in the same velocity condition of the coolant. The critical heat flux increases by the triangular fins on the cooling surface due to the effect of the combination cooling with film boiling and nucleate boiling.

  12. Pedestal evolution physics in low triangularity JET tokamak discharges with ITER-like wall

    Science.gov (United States)

    Bowman, C.; Dickinson, D.; Horvath, L.; Lunniss, A. E.; Wilson, H. R.; Cziegler, I.; Frassinetti, L.; Gibson, K.; Kirk, A.; Lipschultz, B.; Maggi, C. F.; Roach, C. M.; Saarelma, S.; Snyder, P. B.; Thornton, A.; Wynn, A.; Contributors, JET

    2018-01-01

    The pressure gradient of the high confinement pedestal region at the edge of tokamak plasmas rapidly collapses during plasma eruptions called edge localised modes (ELMs), and then re-builds over a longer time scale before the next ELM. The physics that controls the evolution of the JET pedestal between ELMs is analysed for 1.4 MA, 1.7 T, low triangularity, δ  =  0.2, discharges with the ITER-like wall, finding that the pressure gradient typically tracks the ideal magneto-hydrodynamic ballooning limit, consistent with a role for the kinetic ballooning mode. Furthermore, the pedestal width is often influenced by the region of plasma that has second stability access to the ballooning mode, which can explain its sometimes complex evolution between ELMs. A local gyrokinetic analysis of a second stable flux surface reveals stability to kinetic ballooning modes; global effects are expected to provide a destabilising mechanism and need to be retained in such second stable situations. As well as an electron-scale electron temperature gradient mode, ion scale instabilities associated with this flux surface include an electro-magnetic trapped electron branch and two electrostatic branches propagating in the ion direction, one with high radial wavenumber. In these second stability situations, the ELM is triggered by a peeling-ballooning mode; otherwise the pedestal is somewhat below the peeling-ballooning mode marginal stability boundary at ELM onset. In this latter situation, there is evidence that higher frequency ELMs are paced by an oscillation in the plasma, causing a crash in the pedestal before the peeling-ballooning boundary is reached. A model is proposed in which the oscillation is associated with hot plasma filaments that are pushed out towards the plasma edge by a ballooning mode, draining their free energy into the cooler plasma there, and then relaxing back to repeat the process. The results suggest that avoiding the oscillation and maximising the region

  13. Vagal nerve endings in visceral pleura and triangular ligaments of the rat lung.

    Science.gov (United States)

    Wang, Feng-Bin; Liao, Yi-Han; Wang, Yao-Chen

    2017-02-01

    The inner thoracic cavity is lined by the parietal pleura, and the lung lobes are covered by the visceral pleura. The parietal and visceral plurae form the pleural cavity that has negative pressure within to enable normal respiration. The lung tissues are bilaterally innervated by vagal and spinal nerves, including sensory and motor components. This complicated innervation pattern has made it difficult to discern the vagal vs. spinal processes in the pulmonary visceral pleura. With and without vagotomy, we identified vagal nerve fibres and endings distributed extensively in the visceral pleura ('P'-type nerve endings) and triangular ligaments ('L'-type nerve endings) by injecting wheat germ agglutinin-horseradish peroxidase as a tracer into the nucleus of solitary tract or nodose ganglion of male Sprague-Dawley rats. We found the hilar and non-hilar vagal pulmonary pleural innervation pathways. In the hilar pathway, vagal sub-branches enter the hilum and follow the pleural sheet to give off the terminal arborizations. In the non-hilar pathway, vagal sub-branches run caudally along the oesophagus and either directly enter the ventral-middle-mediastinal left lobe or follow the triangular ligaments to enter the left and inferior lobe. Both vagi innervate: (i) the superior, middle and accessory lobes on the ventral surfaces that face the heart; (ii) the dorsal-rostral superior lobe; (iii) the dorsal-caudal left lobe; and (iv) the left triangular ligament. Innervated only by the left vagus is: (i) the ventral-rostral and dorsal-rostral left lobe via the hilar pathway; (ii) the ventral-middle-mediastinal left lobe and the dorsal accessory lobe that face the left lobe via the non-hilar pathway; and (iii) the ventral-rostral inferior lobe that faces the heart. Innervated only by the right vagus, via the non-hilar pathway, is: (i) the inferior (ventral and dorsal) and left (ventral only) lobe in the area near the triangular ligament; (ii) the dorsal-middle-mediastinal left

  14. Higher-order triangular spectral element method with optimized cubature points for seismic wavefield modeling

    Science.gov (United States)

    Liu, Youshan; Teng, Jiwen; Xu, Tao; Badal, José

    2017-05-01

    The mass-lumped method avoids the cost of inverting the mass matrix and simultaneously maintains spatial accuracy by adopting additional interior integration points, known as cubature points. To date, such points are only known analytically in tensor domains, such as quadrilateral or hexahedral elements. Thus, the diagonal-mass-matrix spectral element method (SEM) in non-tensor domains always relies on numerically computed interpolation points or quadrature points. However, only the cubature points for degrees 1 to 6 are known, which is the reason that we have developed a p-norm-based optimization algorithm to obtain higher-order cubature points. In this way, we obtain and tabulate new cubature points with all positive integration weights for degrees 7 to 9. The dispersion analysis illustrates that the dispersion relation determined from the new optimized cubature points is comparable to that of the mass and stiffness matrices obtained by exact integration. Simultaneously, the Lebesgue constant for the new optimized cubature points indicates its surprisingly good interpolation properties. As a result, such points provide both good interpolation properties and integration accuracy. The Courant-Friedrichs-Lewy (CFL) numbers are tabulated for the conventional Fekete-based triangular spectral element (TSEM), the TSEM with exact integration, and the optimized cubature-based TSEM (OTSEM). A complementary study demonstrates the spectral convergence of the OTSEM. A numerical example conducted on a half-space model demonstrates that the OTSEM improves the accuracy by approximately one order of magnitude compared to the conventional Fekete-based TSEM. In particular, the accuracy of the 7th-order OTSEM is even higher than that of the 14th-order Fekete-based TSEM. Furthermore, the OTSEM produces a result that can compete in accuracy with the quadrilateral SEM (QSEM). The high accuracy of the OTSEM is also tested with a non-flat topography model. In terms of computational

  15. Higher-order triangular spectral element method with optimized cubature points for seismic wavefield modeling

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Youshan, E-mail: ysliu@mail.iggcas.ac.cn [State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029 (China); Teng, Jiwen, E-mail: jwteng@mail.iggcas.ac.cn [State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029 (China); Xu, Tao, E-mail: xutao@mail.iggcas.ac.cn [State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029 (China); CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101 (China); Badal, José, E-mail: badal@unizar.es [Physics of the Earth, Sciences B, University of Zaragoza, Pedro Cerbuna 12, 50009 Zaragoza (Spain)

    2017-05-01

    The mass-lumped method avoids the cost of inverting the mass matrix and simultaneously maintains spatial accuracy by adopting additional interior integration points, known as cubature points. To date, such points are only known analytically in tensor domains, such as quadrilateral or hexahedral elements. Thus, the diagonal-mass-matrix spectral element method (SEM) in non-tensor domains always relies on numerically computed interpolation points or quadrature points. However, only the cubature points for degrees 1 to 6 are known, which is the reason that we have developed a p-norm-based optimization algorithm to obtain higher-order cubature points. In this way, we obtain and tabulate new cubature points with all positive integration weights for degrees 7 to 9. The dispersion analysis illustrates that the dispersion relation determined from the new optimized cubature points is comparable to that of the mass and stiffness matrices obtained by exact integration. Simultaneously, the Lebesgue constant for the new optimized cubature points indicates its surprisingly good interpolation properties. As a result, such points provide both good interpolation properties and integration accuracy. The Courant–Friedrichs–Lewy (CFL) numbers are tabulated for the conventional Fekete-based triangular spectral element (TSEM), the TSEM with exact integration, and the optimized cubature-based TSEM (OTSEM). A complementary study demonstrates the spectral convergence of the OTSEM. A numerical example conducted on a half-space model demonstrates that the OTSEM improves the accuracy by approximately one order of magnitude compared to the conventional Fekete-based TSEM. In particular, the accuracy of the 7th-order OTSEM is even higher than that of the 14th-order Fekete-based TSEM. Furthermore, the OTSEM produces a result that can compete in accuracy with the quadrilateral SEM (QSEM). The high accuracy of the OTSEM is also tested with a non-flat topography model. In terms of computational

  16. Implementations of the optimal multigrid algorithm for the cell-centered finite difference on equilateral triangular grids

    Energy Technology Data Exchange (ETDEWEB)

    Ewing, R.E.; Saevareid, O.; Shen, J. [Texas A& M Univ., College Station, TX (United States)

    1994-12-31

    A multigrid algorithm for the cell-centered finite difference on equilateral triangular grids for solving second-order elliptic problems is proposed. This finite difference is a four-point star stencil in a two-dimensional domain and a five-point star stencil in a three dimensional domain. According to the authors analysis, the advantages of this finite difference are that it is an O(h{sup 2})-order accurate numerical scheme for both the solution and derivatives on equilateral triangular grids, the structure of the scheme is perhaps the simplest, and its corresponding multigrid algorithm is easily constructed with an optimal convergence rate. They are interested in relaxation of the equilateral triangular grid condition to certain general triangular grids and the application of this multigrid algorithm as a numerically reasonable preconditioner for the lowest-order Raviart-Thomas mixed triangular finite element method. Numerical test results are presented to demonstrate their analytical results and to investigate the applications of this multigrid algorithm on general triangular grids.

  17. Triangular Numbers

    Indian Academy of Sciences (India)

    Author Affiliations. Anuradha S Garge1 Shailesh A Shirali2. Centre for Excellence in Basic Sciences, Kalina Campus Mumbai University Mumbai 400 098, India. Community Mathematics Center Rishi Valley School (KFI) Rishi Valley 517 352 Andhra Pradesh, India.

  18. Triangular Numbers

    Indian Academy of Sciences (India)

    Admin

    Left: Anuradha S Garge completed her PhD from. Pune University in 2008 under the supervision of Prof. S A Katre. Her research interests include K-theory and number theory. Besides mathematics, she is interested in (singing) indian classical music and yoga. Right: Shailesh Shirali is. Director of Sahyadri School.

  19. Geometric triangular chiral hexagon crystal-like complexes organization in pathological tissues biological collision order.

    Directory of Open Access Journals (Sweden)

    Jairo A Díaz

    Full Text Available The present study describes and documents self-assembly of geometric triangular chiral hexagon crystal like complex organizations (GTCHC in human pathological tissues. The authors have found this architectural geometric expression at macroscopic and microscopic levels mainly in cancer processes. This study is based essentially on macroscopic and histopathologic analyses of 3000 surgical specimens: 2600 inflammatory lesions and 400 malignant tumours. Geometric complexes identified photographically at macroscopic level were located in the gross surgical specimen, and these areas were carefully dissected. Samples were taken to carry out histologic analysis. Based on the hypothesis of a collision genesis mechanism and because it is difficult to carry out an appropriate methodological observation in biological systems, the authors designed a model base on other dynamic systems to obtain indirect information in which a strong white flash wave light discharge, generated by an electronic device, hits over the lines of electrical conductance structured in helicoidal pattern. In their experimental model, the authors were able to reproduce and to predict polarity, chirality, helicoid geometry, triangular and hexagonal clusters through electromagnetic sequential collisions. They determined that similar events among constituents of extracelular matrix which drive and produce piezoelectric activity are responsible for the genesis of GTCHC complexes in pathological tissues. This research suggests that molecular crystals represented by triangular chiral hexagons derived from a collision-attraction event against collagen type I fibrils emerge at microscopic and macroscopic scales presenting a lateral assembly of each side of hypertrophy helicoid fibers, that represent energy flow in cooperative hierarchically chiral electromagnetic interaction in pathological tissues and arises as a geometry of the equilibrium in perturbed biological systems. Further

  20. A collapse surface for a perforated plate with an equilateral triangular array of penetrations

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, J.L.; Jones, D.P.; Hutula, D.N.; Banas, D.

    1999-02-01

    This paper describes the development of incipient yield and subsequent collapse surfaces for a plate containing a large number of small circular penetrations arranged in an equilateral triangular array. The collapse surface developed here is appropriate for formulating a generic elastic-plastic flow theory for perforated materials. A unit cell is defined to characterize the mechanical response of an equilateral triangular array of penetrations. An elastic-perfectly plastic [EPP] finite element analysis [FEA] computer program is used to calculate the EPP response of the unit cell. A sufficient number of load cases are solved to define the complete incipient yield and collapse surfaces for the unit cell. A fourth order yield function is defined by squaring the Von Mises quadratic yield function and retaining only those terms that are required for the symmetry dictated by the triangular array. Curve fitting is used to determine the coefficients of the fourth order function to match the incipient yield and collapse data calculated for the unit cell by FEA. The incipient yield function in the plane of the plate incorporating the penetration pattern is shown to be almost rhomboidal in shape while the collapse curve is more elliptical. The fourth order yield function which passes through the incipient yield data possess regions where the surface is concave--a concern when developing a plasticity theory based on the function. Fitting the coefficients of the fourth order function to the collapse data results in a curve which is shown to be always convex thus having all positive outward normal vectors which is a required property for the development of plasticity flow theories.

  1. The innervation of the triangular fibrocartilage complex: nitric acid maceration rediscovered.

    Science.gov (United States)

    Gupta, R; Nelson, S D; Baker, J; Jones, N F; Meals, R A

    2001-01-01

    Injury to the triangular fibrocartilage complex (TFCC) is frequently implicated in the etiology of ulnar-sided wrist pain. This study examines the nervous anatomy of the TFCC using a nitric acid maceration technique and attempts to correlate this information with known tear patterns. Ten fresh frozen cadaveric specimens were studied in detail. Gross dissection of each upper-extremity specimen included removal of all flexor and extensor tendons. After identification and labeling with permanent color of the ulnar nerve, dorsal sensory branch of the ulnar nerve, posterior interosseous nerve, anterior interosseous nerve, and median nerve, an en bloc excision of the distal radioulnar region was performed. Digestion of the soft tissue was performed with nitric acid at sequential concentrations of 50% and 33% for 9 of 10 specimens. The digestion was halted by immersing the specimen in a mixture of 10% formaldehyde and 1% glycerine. After removal of bone, the specimens were fixed in paraffin, sectioned, and stained with hematoxylin and eosin. Nine of the 10 specimens were studied microscopically to determine the contribution of the grossly identified nerves to each zone of the triangular fibrocartilage complex as defined by Palmer's classification of acute TFCC tears. The anterior interosseous, median, and superficial radial nerves did not contribute to the innervation of the TFCC. The intraarticular course of the peripheral nerves could not be defined in the one specimen that was not digested with nitric acid. Nitric acid maceration is a rediscovered technique for identifying the nervous anatomy of soft tissues. The study showed that the triangular fibrocartilage complex is innervated by branches of the posterior interosseous, ulnar, and dorsal sensory ulnar nerves in a fairly consistent manner. Improved treatment of TFCC tears may result from an enhanced understanding of the supporting structures' innervation and mechanical function.

  2. A microcomputer program for energy assessment and aggregation using the triangular probability distribution

    Science.gov (United States)

    Crovelli, R.A.; Balay, R.H.

    1991-01-01

    A general risk-analysis method was developed for petroleum-resource assessment and other applications. The triangular probability distribution is used as a model with an analytic aggregation methodology based on probability theory rather than Monte-Carlo simulation. Among the advantages of the analytic method are its computational speed and flexibility, and the saving of time and cost on a microcomputer. The input into the model consists of a set of components (e.g. geologic provinces) and, for each component, three potential resource estimates: minimum, most likely (mode), and maximum. Assuming a triangular probability distribution, the mean, standard deviation, and seven fractiles (F100, F95, F75, F50, F25, F5, and F0) are computed for each component, where for example, the probability of more than F95 is equal to 0.95. The components are aggregated by combining the means, standard deviations, and respective fractiles under three possible siutations (1) perfect positive correlation, (2) complete independence, and (3) any degree of dependence between these two polar situations. A package of computer programs named the TRIAGG system was written in the Turbo Pascal 4.0 language for performing the analytic probabilistic methodology. The system consists of a program for processing triangular probability distribution assessments and aggregations, and a separate aggregation routine for aggregating aggregations. The user's documentation and program diskette of the TRIAGG system are available from USGS Open File Services. TRIAGG requires an IBM-PC/XT/AT compatible microcomputer with 256kbyte of main memory, MS-DOS 3.1 or later, either two diskette drives or a fixed disk, and a 132 column printer. A graphics adapter and color display are optional. ?? 1991.

  3. Generalizing boundaries for triangular designs, and efficacy estimation at extended follow-ups.

    Science.gov (United States)

    Allison, Annabel; Edwards, Tansy; Omollo, Raymond; Alves, Fabiana; Magirr, Dominic; E Alexander, Neal D

    2015-11-16

    Visceral leishmaniasis (VL) is a parasitic disease transmitted by sandflies and is fatal if left untreated. Phase II trials of new treatment regimens for VL are primarily carried out to evaluate safety and efficacy, while pharmacokinetic data are also important to inform future combination treatment regimens. The efficacy of VL treatments is evaluated at two time points, initial cure, when treatment is completed and definitive cure, commonly 6 months post end of treatment, to allow for slow response to treatment and detection of relapses. This paper investigates a generalization of the triangular design to impose a minimum sample size for pharmacokinetic or other analyses, and methods to estimate efficacy at extended follow-up accounting for the sequential design and changes in cure status during extended follow-up. We provided R functions that generalize the triangular design to impose a minimum sample size before allowing stopping for efficacy. For estimation of efficacy at a second, extended, follow-up time, the performance of a shrinkage estimator (SHE), a probability tree estimator (PTE) and the maximum likelihood estimator (MLE) for estimation was assessed by simulation. The SHE and PTE are viable approaches to estimate an extended follow-up although the SHE performed better than the PTE: the bias and root mean square error were lower and coverage probabilities higher. Generalization of the triangular design is simple to implement for adaptations to meet requirements for pharmacokinetic analyses. Using the simple MLE approach to estimate efficacy at extended follow-up will lead to biased results, generally over-estimating treatment success. The SHE is recommended in trials of two or more treatments. The PTE is an acceptable alternative for one-arm trials or where use of the SHE is not possible due to computational complexity. NCT01067443 , February 2010.

  4. Exploring pentagon-heptagon pair defects in the triangular graphene quantum dots: A computational study

    Energy Technology Data Exchange (ETDEWEB)

    Ghafouri, Reza, E-mail: reghafouri@gmail.com

    2016-06-01

    We have applied density functional calculations to investigate Stone Wales (SW) and carbon ad-dimer (CD) defect formation in triangular graphene quantum dots (GQDs). According to our results, defect formation energies depend on the positions of SW defects, such that the rotation of the C−C bond located near the vertex of triangular GQD is easier than the rotation of other C−C bonds. Therefore, the multiply defective GQDs with isolated SW defect sites are the most favorable while the formation of pentalene like structures in the connected SW defect sites costs larger formation energies. Introducing of carbon dimer defects on a triangular GQD induces a curvature at the defective sites, which leads to a more complex defect configuration with cone-like structure in the CD defective GQD with three defective sites. Then, formation energies for CD defective GQDs are higher than those for SW defective ones. The electrophilicity values calculated for SW and CD defective GQDs are greater than those for pristine GQDs. Moreover, perturbation of strong sp{sup 2} bonding network of graphitic carbons on the GQD, leading to the formation of more localized C−C bonds, results in further electron deficiency of multiply SW and CD defective GQDs with increasing of electrophilicity values. - Highlights: • Defect formation energy depends on positions of SW defects. • Defective GQDs with isolated SW defects are the most favorable. • Introducing of CD defects induces a curvature leading to cone-like structure. • Defect formation energies for CD defective GQDs are higher than those for SW ones. • Electrophilicity: CD defective GQDs > SW defective GQDs > perfect GQDs.

  5. Numerical Study of Thermal Radiation Effect on Confined Turbulent Free Triangular Jets

    Directory of Open Access Journals (Sweden)

    Kiyan Parham

    2013-01-01

    Full Text Available The present study investigates the effects of thermal radiation on turbulent free triangular jets. Finite volume method is applied for solving mass, momentum, and energy equations simultaneously. Discrete ordinate method is used to determine radiation transfer equation (RTE. Results are presented in terms of velocity, kinetic energy, and its dissipation rate fields. Results show that thermal radiation speeds the development of velocity on the jet axis and enhances kinetic energy; therefore, when radiation is added to free jet its mixing power, due to extra kinetic energy, increases.

  6. Algebraic Bethe ansatz for the XXX chain with triangular boundaries and Gaudin model

    Science.gov (United States)

    Cirilo António, N.; Manojlović, N.; Salom, I.

    2014-12-01

    We implement fully the algebraic Bethe ansatz for the XXX Heisenberg spin chain in the case when both boundary matrices can be brought to the upper-triangular form. We define the Bethe vectors which yield the strikingly simple expression for the off shell action of the transfer matrix, deriving the spectrum and the relevant Bethe equations. We explore further these results by obtaining the off shell action of the generating function of the Gaudin Hamiltonians on the corresponding Bethe vectors through the so-called quasi-classical limit. Moreover, this action is as simple as it could possibly be, yielding the spectrum and the Bethe equations of the Gaudin model.

  7. Scattering of electromagnetic waves from surfaces with conformal mapping: An example of a triangular plate.

    Science.gov (United States)

    Chui, S T; Wang, Shubo; Chan, C T

    2016-03-01

    We discuss a way to exploit conformal mapping to study the response of a finite metallic film of arbitrary shape to an external electromagnetic field at finite frequencies. This provides a simple way to understand different physics issues and provides insights that include the issue of vorticity and eddy current and the nature of the divergent electric field at the boundaries and at corners. We study an example of an equilateral triangular plate and find good agreement with results obtained with traditional numerical techniques.

  8. A numerically accurate and robust expression for bistatic scattering from a plane triangular facet

    DEFF Research Database (Denmark)

    Wendelboe, Gorm; Jacobsen, Finn; Bell, Judith

    2006-01-01

    area was applied instead. The effective ensonified area solution is exact at normal incidence, but at other angles, where singularities also exist, the scattered pressure will be incorrect. This paper presents a frequency domain expression generalized to bistatic scattering written in terms of sinc...... is found by application of the Kirchhoff approximation. Fawcett [J. Acoust. Soc. Am. 109, 1319–1320 (2001)] derived a time domain expression for the backscattered pressure from a triangular facet, but the expression encountered numerical problems at certain angles, and therefore, the effective ensonified...... functions; it is shown that the expression improves the computational accuracy without loss of robustness....

  9. On performance analysis of ADRC for a class of MIMO lower-triangular nonlinear uncertain systems.

    Science.gov (United States)

    Xue, Wenchao; Huang, Yi

    2014-07-01

    This paper designs the active disturbance rejection control (ADRC) to achieve desired performance for a class of MIMO lower-triangular nonlinear systems with large uncertainties under un-matched condition. We develop the ADRC with a set of extended state observers, and prove that the closed-loop system can achieve satisfied dynamic performance. The theoretical results illustrate the relationship between the bound of the concerned error and the bandwidth of extend state observers. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Effects of an upstream triangular plate on the wing-body junction flow

    Science.gov (United States)

    Théberge, M.-A.; Ekmekci, A.

    2017-09-01

    The use of a short triangular leading-edge plate at the base of a wing-body junction is experimentally evaluated as a passive control method to eliminate the horseshoe vortices or at least to subdue their strength. The impact of the plate geometry on the efficacy of the control is assessed by considering triangular plates that have a length of 1T, 2T, and 3T, a width of 0.1T and 0.2T, and a height of 1.5T, where T is the maximum thickness of the wing. The wing model is a NACA 0020 airfoil. The Reynolds number based on the chord length is varied from Rec = 25 000 to 75 000. The incoming boundary layer is laminar in all experiments. Particle Image Velocimetry is utilized to characterize the temporal behavior and circulation strength of horseshoe vortices. The λ2-criterion is used as the vortex identification method. All the triangular leading-edge plates investigated in this study are found to decrease the circulation strength of the horseshoe vortices in the symmetry plane, although by varying degrees, compared to the baseline configuration that has no plate control. An increase in the upstream reach of the leading-edge plate significantly mitigates the vortical organization, vorticity, size, and circulation strength of horseshoe vortices. Although all plate lengths in question achieve a regression in the horseshoe vortex regime and, at the lowest Reynolds number considered, they all reduce the number of horseshoe vortices compared to the uncontrolled case, as the Reynolds number increases, longer plates are needed for such an effect. On the other hand, an increase in the thickness of the leading-edge plate deteriorates the desired control by increasing the vortical organization, vorticity magnitude, size, and circulation strength of horseshoe vortices. At higher Reynolds numbers, a thicker plate performs even poorer, resulting in extra horseshoe vortices, which can be unsteady depending on the Reynolds number. Nevertheless, all the triangular plates considered in

  11. Description of a new coral species Ctenactis triangular is (Scleractinia: Fungiidae from Andaman Islands, India

    Directory of Open Access Journals (Sweden)

    T. Mondal

    2013-08-01

    Full Text Available A new species of scleractinian coral Ctenactis triangularis sp. nov. in the family Fungiidae has been described from the Andaman and Nicobar Islands. This species has a triangular arm shaped corallum with the mouth extending along all three arms. Septal dentition is long, cylindrical, equally sized and closely arranged. Numerous pits on the costae and costal spines are spinulose. Ctenactis triangularis sp. nov. has an affinity with Ctenactis echinata (Pallas, 1766, Ctenactis crassa (Dana, 1846 and Ctenactis albitentaculata (Hoeksema, 1989, thus the morphological features have been compared with these three species and discussed.

  12. Subspace-Based Noise Reduction for Speech Signals via Diagonal and Triangular Matrix Decompositions

    DEFF Research Database (Denmark)

    Hansen, Per Christian; Jensen, Søren Holdt

    We survey the definitions and use of rank-revealing matrix decompositions in single-channel noise reduction algorithms for speech signals. Our algorithms are based on the rank-reduction paradigm and, in particular, signal subspace techniques. The focus is on practical working algorithms, using both...... diagonal (eigenvalue and singular value) decompositions and rank-revealing triangular decompositions (ULV, URV, VSV, ULLV and ULLIV). In addition we show how the subspace-based algorithms can be evaluated and compared by means of simple FIR filter interpretations. The algorithms are illustrated...

  13. Productos Estrella y Ecuación Cuántica Triangular de Yang-Baxter

    OpenAIRE

    Valero Burguete, Luís

    2011-01-01

    Se demuestran teoremas enunciados por v.g. Drinfeld sobre la relacion entre la ecuación cuántica triangular de yang-baxter (ectyb) y los productos estrella invariantes sobre un grupo de lie g con estructura de poisson invariante. Se enuncia y prueba un teorema básico que pone de manifiesto el contenido cohomologico de la ectyb. La obstrucción a la prolongación al orden k+1 de un producto estrella invariante f(x;y) al orden k, es la clase de cohomologia (invariante de hochschild) correspondien...

  14. Topological phases characterized by spin Chern number and skyrmion number in triangular Bose-Hubbard model

    Science.gov (United States)

    Guo, Long-Fei; Li, Peng

    2017-08-01

    Topological phases are important topics in condensed matter physics. Here, we investigate a spin-orbit coupling Bose-Hubbard model in triangular lattice. In the strong coupling limit, we obtained the single particle Green’s function and constructed the phase diagram for ground states. We found two types of nontrivial topological ground phases characterized by spin Chern number and skyrmion number, respectively. The spin Chern numbers characterize the spin Chern insulators. While the skyrmion numbers characterize the skyrmion textures. We show that the phase transitions between different spin Chern insulators take place with gap closing and reopening. While the phase transitions between different skyrmion textures occur without gap closing.

  15. Algebraic Bethe ansatz for the XXX chain with triangular boundaries and Gaudin model

    Energy Technology Data Exchange (ETDEWEB)

    Cirilo António, N., E-mail: nantonio@math.ist.utl.pt [Centro de Análise Funcional e Aplicações, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa (Portugal); Manojlović, N., E-mail: nmanoj@ualg.pt [Grupo de Física Matemática da Universidade de Lisboa, Av. Prof. Gama Pinto 2, PT-1649-003 Lisboa (Portugal); Departamento de Matemática, F.C.T., Universidade do Algarve, Campus de Gambelas, PT-8005-139 Faro (Portugal); Salom, I., E-mail: isalom@ipb.ac.rs [Institute of Physics, University of Belgrade, P.O. Box 57, 11080 Belgrade (Serbia)

    2014-12-15

    We implement fully the algebraic Bethe ansatz for the XXX Heisenberg spin chain in the case when both boundary matrices can be brought to the upper-triangular form. We define the Bethe vectors which yield the strikingly simple expression for the off shell action of the transfer matrix, deriving the spectrum and the relevant Bethe equations. We explore further these results by obtaining the off shell action of the generating function of the Gaudin Hamiltonians on the corresponding Bethe vectors through the so-called quasi-classical limit. Moreover, this action is as simple as it could possibly be, yielding the spectrum and the Bethe equations of the Gaudin model.

  16. The magnetic structure on the ground state of the equilateral triangular spin tube

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Kazuki, E-mail: k703861@eagle.sophia.ac.jp; Goto, Takayuki [Sophia University, Physics Division (Japan); Manaka, Hirotaka [Kagoshima University, Graduate School of Science and Engineering (Japan); Miura, Yoko [Suzuka National College of Technology (Japan)

    2016-12-15

    The ground state of the frustrated equilateral triangular spin tube CsCrF{sub 4} is still hidden behind a veil though NMR spectrum broaden into 2 T at low temperature. In order to investigate the spin structure in an ordered state by {sup 19}F-NMR, we have determined the anisotropic hyperfine coupling tensors for each three fluorine sites in the paramagnetic state. The measurement field was raised up to 10 T to achieve highest resolution. The preliminary analysis using the obtained hyperfine tensors has shown that the archetypal 120°-type structure in ab-plane does not accord with the NMR spectra of ordered state.

  17. Anisotropic anomalous Hall effect in triangular itinerant ferromagnet Fe3GeTe2

    Science.gov (United States)

    Wang, Yihao; Xian, Cong; Wang, Jian; Liu, Bingjie; Ling, Langsheng; Zhang, Lei; Cao, Liang; Qu, Zhe; Xiong, Yimin

    2017-10-01

    Magnetic frustrated materials are of great interest for their novel spin-dependent transport properties. We report an anisotropic anomalous Hall effect in the triangular itinerant ferromagnet Fe3GeTe2 . When the current flows along the a b plane, Fe3GeTe2 exhibits the conventional anomalous Hall effect below the Curie temperature Tc, which can be depicted by Karplus-Luttinger theory. On the other hand, the topological Hall effect shows up below Tc with current along the c axis. The enhancement of Hall resistivity can be attributed to the chiral effect during the spin-flop process.

  18. Adaptive Finite Volume Method for the Shallow Water Equations on Triangular Grids

    Directory of Open Access Journals (Sweden)

    Sudi Mungkasi

    2016-01-01

    Full Text Available This paper presents a numerical entropy production (NEP scheme for two-dimensional shallow water equations on unstructured triangular grids. We implement NEP as the error indicator for adaptive mesh refinement or coarsening in solving the shallow water equations using a finite volume method. Numerical simulations show that NEP is successful to be a refinement/coarsening indicator in the adaptive mesh finite volume method, as the method refines the mesh or grids around nonsmooth regions and coarsens them around smooth regions.

  19. The Implementation of Cumulative Learning Theory in Calculating Triangular Prism and Tube Volumes

    Science.gov (United States)

    Muklis, M.; Abidin, C.; Pamungkas, M. D.; Masriyah

    2018-01-01

    This study aims at describing the application of cumulative learning theory in calculating the volume of a triangular prism and a tube as well as revealing the students’ responses toward the learning. The research method used was descriptive qualitative with elementary school students as the subjects of the research. Data obtained through observation, field notes, questionnaire, tests, and interviews. The results from the application of cumulative learning theory obtained positive students’ responses in following the learning and students’ learning outcomes was dominantly above the average. This showed that cumulative learning could be used as a reference to be implemented in learning, so as to improve the students’ achievement.

  20. Pt/Fe₃O₄ Core/Shell Triangular Nanoprisms by Heteroepitaxy: Facet Selectivity at the Pt-Fe₃O₄ Interface and the Fe₃O₄ Outer Surface.

    Science.gov (United States)

    Jiang, Maowei; Liu, Wei; Yang, Xiaoli; Jiang, Zheng; Yao, Tao; Wei, Shiqiang; Peng, Xiaogang

    2015-11-24

    Pt/Fe3O4 core/shell triangular nanoprisms were synthesized using seed-mediated heteroepitaxy. Their well-defined shape, facets, and ordered-assembly allowed detailed analysis of mechanism of the heteroepitaxy. At the Pt-Fe3O4 interface, existence of both lattice and chemical mismatch resulted in facet-selective epitaxy along ⟨111⟩ directions of two lattices. X-ray absorption fine structure measurements demonstrated that the Pt seed nanocrystals were composed of an iron-rich Pt-Fe metallic thin layer sandwiched between the Pt core and a Fe-O outer-surface. The Fe-O outer-surface of the seed nanocrystals presumably offered epitaxial sites for the following deposition of the Fe3O4 shell. Each tip and side of a triangular nanoprism respectively possessed a groove and a ridge, and a (111) plane parallel to the basal planes linked all grooves and ridges. This interesting (111) plane approximately bisected the triangle nanoprisms and located near the Pt-seed. The outer surface of the hybrid nanocrystals was also found to be facet-selective, that is, solely {111} facets of Fe3O4 lattice. These polar {111} facets allowed the surface to be only occupied with high-density iron ions, and thus offered best surface coordination for the electron donating ligands in the solution.

  1. Penile prosthesis implant with bi-triangular excision and graft for surgical therapy of Peyronie’s disease: A case report

    Directory of Open Access Journals (Sweden)

    Alexandre de Freitas Miranda

    2016-01-01

    Full Text Available We present a case of a 65-year-old man, who presented with moderate erectile dysfunction and a dorsal penile deviation of 60° caused by Peyronie’s disease. The patient underwent bi-triangularshaped plaque excision, followed by grafting and implantation of inflatable penile prosthesis. Complete penile straightening, without mechanical or geometric abnormalities, was achieved using bi-triangular excision and grafting. Postoperatively, the patient reported high satisfaction with the results and could perform sexual intercourse naturally. This novel technique corrects any degree of penile curvature, permits malleable and semi-rigid penile prosthesis implantation, avoids penile length loss, and eliminates additional incisions. To our knowledge, this case is the first in the literature in which the bi-triangular technique was successfully used for penile prosthesis implantation secondary to Peyronie’s disease. This new technique appears to be a good solution to correct penile curvature during penile prosthesis implantation for the treatment of Peyronie’s disease associated with erectile dysfunction.

  2. Reduced turbulence and H-mode confinement in L-mode negative triangularity discharges on DIII-D

    Science.gov (United States)

    Marinoni, A.; Austin, M. E.; Walker, M. L.; Hyatt, A. W.; Petty, C. C.; Thome, K. H.; Porkolab, M.; Rost, J. C.; Davis, E. M.; McKee, G. R.; Rhodes, T. L.; Sung, C.; Sauter, O.; DIII-D Team; MIT-PSFC Collaboration

    2017-10-01

    DIII-D has produced inner-wall limited plasmas with an L-mode edge at negative triangularity characterized by confinement and fluctuation levels comparable to those in H-mode plasmas at positive triangularity. On TCV, similar plasmas at low collisionality and with pure electron heating showedimproved energy confinement, as compared to matched discharges at positive triangularity, due to modifications to the toroidal precession drift of trapped electrons. The recent DIII-D experiment used both ECH and NBI heating, thus exploring a more reactor relevant regime where Te Ti. Compared to matched positive triangularity discharges, the intensity of density and temperaturefluctuations is reduced at negative triangularity both in ECH and in NBI dominated phases. Preliminary TGLF runs indicate the discharges are dominated by TEM modes. More detailed analysis will explore the role of the toroidal precession drift in this new regime. Work supported by US DOE under DE-FG02-94ER54235 and DE-FC02-04ER54698.

  3. Crystalline Electric-Field Randomness in the Triangular Lattice Spin-Liquid YbMgGaO_{4}.

    Science.gov (United States)

    Li, Yuesheng; Adroja, Devashibhai; Bewley, Robert I; Voneshen, David; Tsirlin, Alexander A; Gegenwart, Philipp; Zhang, Qingming

    2017-03-10

    We apply moderate-high-energy inelastic neutron scattering (INS) measurements to investigate Yb^{3+} crystalline electric field (CEF) levels in the triangular spin-liquid candidate YbMgGaO_{4}. Three CEF excitations from the ground-state Kramers doublet are centered at the energies ℏω=39, 61, and 97 meV in agreement with the effective spin-1/2 g factors and experimental heat capacity, but reveal sizable broadening. We argue that this broadening originates from the site mixing between Mg^{2+} and Ga^{3+} giving rise to a distribution of Yb-O distances and orientations and, thus, of CEF parameters that account for the peculiar energy profile of the CEF excitations. The CEF randomness gives rise to a distribution of the effective spin-1/2 g factors and explains the unprecedented broadening of low-energy magnetic excitations in the fully polarized ferromagnetic phase of YbMgGaO_{4}, although a distribution of magnetic couplings due to the Mg/Ga disorder may be important as well.

  4. Electron-related linear and nonlinear optical responses in vertically coupled triangular quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Martínez-Orozco, J.C. [Unidad Académica de Física. Universidad Autónoma de Zacatecas, Calzada Solidaridad esquina con Paseo la Bufa S/N, C.P. 98060. Zacatecas, Zac. (Mexico); Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Mora-Ramos, M.E. [Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Ave. Universidad 1001, CP 62209, Cuernavaca, Morelos (Mexico); Duque, C.A., E-mail: cduque@fisica.udea.edu.co [Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia)

    2014-11-01

    The conduction band states of GaAs-based vertically coupled double triangular quantum dots in two dimensions are investigated within the effective mass and parabolic approximation, using a diagonalization procedure to solve the corresponding Schrödinger-like equation. The effect of an externally applied static electric field is included in the calculation, and the variation of the lowest confined energy levels as a result of the change of the field strength is reported for different geometrical setups. The linear and nonlinear optical absorptions and the relative change of the refractive index, associated with the energy transition between the ground and the first excited state in the system, are studied as a function of the incident light frequency for distinct configurations of inter-dot distance and electric field intensities. The blueshift of the resonant absorption peaks is detected as a consequence of the increment in the field intensity, whereas the opposite effect is obtained from the increase of inter-dot vertical distance. It is also shown that for large enough values of the electric field there is a quenching of the optical absorption due to field-induced change of symmetry of the first excited state wavefunction, in the case of triangular dots of equal shape and size.

  5. Triangular node for Transmission-Line Modeling (TLM) applied to bio-heat transfer.

    Science.gov (United States)

    Milan, Hugo F M; Gebremedhin, Kifle G

    2016-12-01

    Transmission-Line Modeling (TLM) is a numerical method used to solve complex and time-domain bio-heat transfer problems. In TLM, rectangles are used to discretize two-dimensional problems. The drawback in using rectangular shapes is that instead of refining only the domain of interest, a large additional domain will also be refined in the x and y axes, which results in increased computational time and memory space. In this paper, we developed a triangular node for TLM applied to bio-heat transfer that does not have the drawback associated with the rectangular nodes. The model includes heat source, blood perfusion (advection), boundary conditions and initial conditions. The boundary conditions could be adiabatic, temperature, heat flux, or convection. A matrix equation for TLM, which simplifies the solution of time-domain problems or solves steady-state problems, was also developed. The predicted results were compared against results obtained from the solution of a simplified two-dimensional problem, and they agreed within 1% for a mesh length of triangular faces of 59µm±9µm (mean±standard deviation) and a time step of 1ms. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Linear and nonlinear intersubband optical properties in a triangular quantum ring

    Energy Technology Data Exchange (ETDEWEB)

    Nasri, Djillali [Faculté des Sciences Appliquées, Département de Génie Electrique, Université Ibn-Khaldoun de Tiaret, Zaaroura BP No.78, Tiaret 14000 (Algeria); Laboratoire de Microphysique et de Nanophysique (LaMiN), Ecole Nationale Polytechnique d’Oran, BP 1523 EL M’Naouer, Oran 31000 (Algeria); Bettahar, N [Faculté des Sciences de la matière, Département de Physique, Université Ibn-Khaldoun de Tiaret, Zaaroura, BP No.78, Tiaret 14000 (Algeria)

    2015-12-01

    Using the effective mass approximation, within the plane wave expansion, the linear and nonlinear coefficients absorption and the refractive index changes relative to the intersubband transitions in the conduction band of an Al{sub x}Ga{sub 1−x}As/ GaAs/Al{sub x}Ga{sub 1−x}As triangular quantum ring for an x-polarization and an y-polarization of the incident light are calculated. It is found that the transition energy between the ground state and the first two excited states and their related optical matrix are strongly influenced by the length of the side of the inner triangle, leading to a red-shift and blue-shift of the resonant peaks of the intersubband optical absorption, for an x-polarized light absorption and an y-polarized light absorption respectively. Our results are qualitatively similar to those of a triangular quantum wire in the presence of an intense laser field in recent literature.

  7. Fabrication and Localized Surface Plasmon Properties of Triangular Gold Nanowell Arrays in a Glass Substrate.

    Science.gov (United States)

    Jung, Bongsu; Frey, Wolfgang

    2015-01-01

    Nanowell structure has been attractive in plasmonics, surface enhanced Raman scattering, nanocrystal synthesis, and biomolecular immobilization. Conventional nanowell structures have been carved into continuous thin metal films. This letter focuses on the fabrication and characterization of triangular gold nanowell arrays embedded in a back-filled non-metallic and transparent substrate. The nanowell dimensions can be controlled to produce an optically tunable localized surface plasmon resonance (LSPR) as a plasmonic sensor. AFM and LSPR spectroscopy confirm that the triangular Au nanowell structures are partially embedded in the surface of a transparent glass substrate to protect the shape and sharp features of the nanowell. Experimental spectral results and numerical calculations show that the extinction maximum of the LSPR is located in the NIR range, and correlates linearly with the base thickness of the nanowell. Numerical calculations to analyze the extinction spectrum of gold nanowell show that scattering of the nanostructure is dominant to compare to its absorption. LSPR-tunable nanowells can potentially be used for plasmonic sensors and biomolecular docking system platforms.

  8. Global phase diagram and quantum spin liquids in a spin-1/2 triangular antiferromagnet

    Science.gov (United States)

    Gong, Shou-Shu; Zhu, W.; Zhu, J.-X.; Sheng, D. N.; Yang, Kun

    2017-08-01

    We study the spin-1 /2 Heisenberg model on the triangular lattice with the nearest-neighbor J1>0 , the next-nearest-neighobr J2>0 Heisenberg interactions, and the additional scalar chiral interaction Jχ(S⃗i×S⃗j) .S⃗k for the three spins in all the triangles using large-scale density matrix renormalization group calculation on cylinder geometry. With increasing J2 (J2/J1≤0.3 ) and Jχ (Jχ/J1≤1.0 ) interactions, we establish a quantum phase diagram with the magnetically ordered 120∘, stripe, and noncoplanar tetrahedral phase. In between these magnetic order phases, we find a chiral spin liquid (CSL) phase, which is identified as a ν =1 /2 bosonic fractional quantum Hall state with possible spontaneous rotational symmetry breaking. By switching on the chiral interaction, we find that the previously identified spin liquid in the J1-J2 triangular model (0.08 ≲J2/J1≲0.15 ) shows a phase transition to the CSL phase at very small Jχ. We also compute the spin triplet gap in both spin liquid phases, and our finite-size results suggest a large gap in the odd topological sector but a small or vanishing gap in the even sector. We discuss the implications of our results on the nature of the spin liquid phases.

  9. Four-triangular-skin-flap approach to umbilical diseases and laparoscopic umbilical port.

    Science.gov (United States)

    Kaneko, Kenitiro; Tsuda, Mineyuki

    2004-09-01

    Surgery of umbilical pathology requires restoration of a normal umbilical appearance. Also, the umbilicus is used increasingly as the entry site during laparoscopic surgery. However, conventional approaches leave obvious scars. A simple alternative approach that creates a natural-looking umbilicus is described. The umbilicus is opened by creating 4 isosceles triangular skin flaps. Closure is by suture of the flap apex only, creating scaring that resembles a natural umbilicus. Between November 1996 and March 2003, this technique was used in 204 children with umbilical hernia, 2 children with a small omphalocele, 1 child with a patent omphalomesenteric duct, 2 children with a urachal abscess, and 7 children with an umbilical granuloma. Five children underwent initial trocar insertion during laparoscopic surgery via this approach. All procedures were performed uneventfully. Transient erythema of one flap occurred in 64 patients (29.2%). Infection developed in 10 patients (5.0%) but was treated with oral antibiotics. The postoperative umbilical appearance was satisfactory in all but 5 patients. The 4-triangular-skin-flap approach is useful for umbilical diseases and laparoscopic umbilical port access.

  10. Antioxidant, Iron Chelating and Tyrosinase Inhibitory Activities of Extracts from Talinum triangulare Leach Stem

    Directory of Open Access Journals (Sweden)

    Ana Paula Oliveira Amorim

    2013-07-01

    Full Text Available The aim of this work is to evaluate the antioxidant activity against the radical species DPPH, the reducing capacity against Fe II ions, and the inhibitory activity on the tyrosinase enzyme of the T. triangulare. Hydromethanolic crude extract provided two fractions after the liquid/liquid partition with chloroform. The Folin-Ciocalteu method determined the total phenolic content of the crude extract (CE and the hydromethanolic fraction (Fraction 1, resulting in a concentration of 0.5853 g/100 g for Fraction 1, and 0.1400 g/100 g for the CE. Taking into account the results of the DPPH, the free radical scavenging capacity was confirmed. The formation of complexes with Fe II ions was evaluated by UV/visible spectrometry; results showed that CE has complexing power similar to the positive control (Gingko biloba extract.The inhibitory capacity of samples against the tyrosinase enzyme was determined by the oxidation of L-DOPA, providing IC50 values of 13.3 μg·mL−1 (CE and 6.6 μg·mL−1 (Fraction 1. The values indicate that Fraction 1 was more active and showed a higher inhibitory power on the tyrosinase enzyme than the ascorbic acid, used as positive control. The hydromethanolic extract of T. triangulare proved to have powerful antioxidant activity and to inhibit the tyrosinase enzyme; its potential is increased after the partition with chloroform.

  11. Shape effect on the second order nonlinear optical properties in triangular quantum dots with applied electric field

    Science.gov (United States)

    Li, Keyin; Guo, Kangxian; Liang, Litao

    2017-11-01

    The shape effect of triangular quantum dots (TQDs) on the second-harmonic generations (SHG) coefficient and the optical rectification (OR) coefficient with the applied electric field has been theoretically investigated, by using the compact-density-matrix approach and iterative method. Within the effective-mass approximation, the energy levels and the wave functions of the system are obtained. The results show that both the strength of external electric field and the shape of triangular quantum dots have a significant influence on the second-harmonic generations and the optical rectification.

  12. Image recognition of triangular tissue of an organ pulled by forceps in surgical working area for laparoscope robot.

    Science.gov (United States)

    Nakasuji, Hisa; Naruki, Kazuki; Kawai, Toshikazu; Nishikawa, Atsushi; Nishizawa, Yuji; Nakamura, Tatsuo

    2017-07-01

    An image processing method using selected corner points and ridge lines to recognize triangular tissue of an organ pulled by forceps in a laparoscopic view has been developed. The proposed method could be used for semi-automatic control of a laparoscope robot. It makes use of a masking process based on the recognition of the forceps and clots, detection of corner points for a Delaunay diagram, detection of ridge lines oriented in the same direction, and recognition of the triangular working area. Triangles recognized in laparoscopic surgical videos using this method were similar to the correct triangles made by an endoscopic specialist.

  13. Oscillator Strength and Absorption Cross-section of Core-Shell Triangular Quantum Wire for Intersubband Transition

    Science.gov (United States)

    Deyasi, Arpan; Das, N. R.

    Oscillator strength and absorption cross-section of core-shell triangular quantum wire is computed for intersubband optical transition between ground state and first excited state. Kane type band nonparabolicity of first order is considered to study the shift of cross-section peak with incident radiation, and also of the oscillator strength with structural parameters. Results are compared with that obtained from parabolic overestimation. Results show that both oscillator strength and peak magnitude of absorption cross-section decreases with increasing dimension, and the rate is significant when nonparabolic dispersion relation is taken into account. Findings are important for designing optical emitter/detector using core-shell triangular quantum wire.

  14. Sobre relaciones laborales triangulares: La subcontratación y el suministro de trabajadores

    Directory of Open Access Journals (Sweden)

    José Luis Ugarte Cataldo

    2006-01-01

    Full Text Available Las relaciones laborales triangulares puede adoptar, en lo fundamental, dos modalidades: la subcontratación laboral y el suministro de trabajadores por la vía de una empresa de trabajo temporal. La primera se refiere a la situación en que una empresa, dueña de una obra o faena, contrata a otra empresa, denominada contratista, mediante un contrato civil o comercial, para que ejecute a su cuenta y riesgo, con sus propios trabajadores, un determinado trabajo o servicio, pudiendo esta última a su turno, contratar a otra empresa, denominada subcontratista, para que lleve a cabo el trabajo o servicio requerido. La segunda, en cambio, consiste en que una empresa, cuyo giro corresponde al suministro de trabajadores (empresa suministradora o de trabajo temporal, pone a disposición de otra empresa (denominada usuaria, por el pago de un precio determinado, los servicios laborales de sus empleados, reteniendo para sí la calidad formal de empleador. En Chile, mientras la figura de la subcontratación laboral data de antiguo, y está regulada en la legislación vigente, el caso del suministro es distinto: sólo en los últimos años se presenta como un fenómeno de relevancia para la comunidad jurídica nacional, en directa relación con el momento de moda que vive la denominada descentralización productiva, que no se encuentra, por lo demás, reconocida en nuestra legislación laboral. La regulación de ambos tipos de relaciones triangulares es el objetivo al que va a la dirigido nueva ley de subcontratación: por una parte, se reconoce y regula por primera vez en Chile la figura del suministro de personal a través de lo que denomina empresas de servicios transitorios, y se perfecciona, por otra, la regulación de la subcontratación laboral mediante nuevas normas sobre la responsabilidad del dueño de la obraThe triangular labour relations could basically adopt two modalities: labour subcontracting and the supplying of workers by a temporary

  15. Quantum interference and electron correlation in charge transport through triangular quantum dot molecules.

    Science.gov (United States)

    Chen, Chih-Chieh; Chang, Yia-chung; Kuo, David M T

    2015-03-07

    We study the charge transport properties of triangular quantum dot molecules (TQDMs) connected to metallic electrodes, taking into account all correlation functions and relevant charging states. The quantum interference (QI) effect of TQDMs resulting from electron coherent tunneling between quantum dots is revealed and well interpreted by the long distance coherent tunneling mechanism. The spectra of electrical conductance of TQDMs with charge filling from one to six electrons clearly depict the many-body and topological effects. The calculated charge stability diagram for conductance and total occupation numbers matches well with the recent experimental measurements. We also demonstrate that the destructive QI effect on the tunneling current of TQDMs is robust with respect to temperature variation, making the single electron QI transistor feasible at higher temperatures.

  16. Fitting polynomial surfaces to triangular meshes with Voronoi squared distance minimization

    KAUST Repository

    Nivoliers, Vincent

    2012-11-06

    This paper introduces Voronoi squared distance minimization (VSDM), an algorithm that fits a surface to an input mesh. VSDM minimizes an objective function that corresponds to a Voronoi-based approximation of the overall squared distance function between the surface and the input mesh (SDM). This objective function is a generalization of the one minimized by centroidal Voronoi tessellation, and can be minimized by a quasi-Newton solver. VSDM naturally adapts the orientation of the mesh elements to best approximate the input, without estimating any differential quantities. Therefore, it can be applied to triangle soups or surfaces with degenerate triangles, topological noise and sharp features. Applications of fitting quad meshes and polynomial surfaces to input triangular meshes are demonstrated. © 2012 Springer-Verlag London.

  17. Fitting polynomial surfaces to triangular meshes with Voronoi Squared Distance Minimization

    KAUST Repository

    Nivoliers, Vincent

    2011-12-01

    This paper introduces Voronoi Squared Distance Minimization (VSDM), an algorithm that fits a surface to an input mesh. VSDM minimizes an objective function that corresponds to a Voronoi-based approximation of the overall squared distance function between the surface and the input mesh (SDM). This objective function is a generalization of Centroidal Voronoi Tesselation (CVT), and can be minimized by a quasi-Newton solver. VSDM naturally adapts the orientation of the mesh to best approximate the input, without estimating any differential quantities. Therefore it can be applied to triangle soups or surfaces with degenerate triangles, topological noise and sharp features. Applications of fitting quad meshes and polynomial surfaces to input triangular meshes are demonstrated.

  18. Use of triangular membership function for prediction of compressive strength of concrete containing nanosilica

    Directory of Open Access Journals (Sweden)

    Sakshi Gupta

    2015-12-01

    Full Text Available In this paper, application of fuzzy logic technique using triangular membership function for developing models for predicting compressive strength of concrete with partial replacement of cement with nanosilica has been carried out. For this, the data have been taken from various literatures and help in optimizing the constituents available and reducing cost and efforts in studying design to develop mixes by predefining suitable range for experimenting. The use of nanostructured materials in concrete can add many benefits that are directly related to the durability of various cementitious materials, besides the fact that it is possible to reduce the quantities of cement in the composite. Successful prediction by the model indicates that fuzzy logic could be a useful modelling tool for engineers and research scientists in the area of cement and concrete. Compressive strength values of concrete can be predicted in fuzzy logic models without attempting any experiments in a quite short period of time with tiny error rates.

  19. Competing supersolids of Bose-Bose mixtures in a triangular lattice

    Science.gov (United States)

    Trousselet, Fabien; Rueda-Fonseca, Pamela; Ralko, Arnaud

    2014-02-01

    We study the ground-state properties of a frustrated two-species mixture of hard-core bosons on a triangular lattice, as a function of tunable amplitudes for tunneling and interactions. By combining three different methods, a self-consistent cluster mean-field, exact diagonalization, and effective theories, we unravel a very rich and complex phase diagram. More specifically, we discuss the existence of three original mixture supersolids: (i) a commensurate with frozen densities and supersolidity in spin degrees of freedom, in a regime of strong interspecies interactions; and (ii) when this interaction is weaker, two mutually competing incommensurate supersolids. Finally, we show how these phases can be stabilized by a quantum fluctuation enhancement of peculiar insulating parent states.

  20. A novel amplitude modulated triangular carrier gain linearization technique for SPWM inverter

    Directory of Open Access Journals (Sweden)

    Ramkumar Subburam

    2009-01-01

    Full Text Available This paper presents a new method to extend the linearity of the sinusoidal pulse width modulation (SPWM to full range of the pulse dropping region. The proposed amplitude modulated triangular carrier PWM method (AMTCPWM increases the dynamic range of the SPWM control and eliminates the need of nonlinear modulation in the pulse dropping region to reach the square wave boundary. The novel method combines the spectral quality of SPWM with the efficient single-mode linear control. A simple analytical characterization of the exact method is presented and its effectiveness is demonstrated using simulation for the basic single-phase H-bridge inverter circuit. The hardware results of the designed prototype inverter are presented to validate the betterment of the novel scheme. .

  1. Application of the control volume mixed finite element method to a triangular discretization

    Science.gov (United States)

    Naff, R.L.

    2012-01-01

    A two-dimensional control volume mixed finite element method is applied to the elliptic equation. Discretization of the computational domain is based in triangular elements. Shape functions and test functions are formulated on the basis of an equilateral reference triangle with unit edges. A pressure support based on the linear interpolation of elemental edge pressures is used in this formulation. Comparisons are made between results from the standard mixed finite element method and this control volume mixed finite element method. Published 2011. This article is a US Government work and is in the public domain in the USA. ?? 2012 John Wiley & Sons, Ltd. This article is a US Government work and is in the public domain in the USA.

  2. Influence of electron-phonon interaction on quantum phase transition in a triangular triple quantum dot

    Science.gov (United States)

    Kim, Chang-Il; Kang, Chol-Jin; Yun, Chol-Song; Choe, Myong-Il; Ahn, Jong-Kwan

    2017-11-01

    We investigate the quantum phase transition in triple quantum dot system with triangular geometry, in which one of the dots is connected to metallic leads and electrons in the dot interact with a local phonon mode. The influence of electron-phonon interaction on the quantum phase transition between local moment phase and Kondo screened strong coupling phase at the particle-hole symmetric point is studied based on the analytical arguments and the numerical renormalization group method. The results show that the critical value of tunnel-coupling between side dots decreases with the increase of electron-phonon coupling in "spin Kondo" regime. Furthermore, at a certain critical value of electron-phonon coupling, there appears only strong coupling phase, irrespective of tunnel-coupling between dots. The study of the influence of electron-phonon interaction on the quantum phase transition in triple quantum dot has the great importance for clarifying the mechanism of Kondo screening in the system.

  3. Periodic motions of a three-axis gyrostatic satellite at a triangular libration point

    Science.gov (United States)

    Ergasheva, M. E.

    1989-01-01

    Consideration is given to a problem in which the center of mass of a gyrostatic satellite M is located at the L4 triangular libration point of the gravitating bodies M sub 0 and M sub 1, which move with respect to a common center of mass in circular Keplerian orbits. The mass of M is considered to be negligibly small compared with the masses of M sub 0 and M sub 1, and the dimensions of M are considered to be negligibly small compared with the distance between M sub 0 and M sub 1. The periodic motions of the gryostat under the effect of the gravitational moments produced by M sub 0 and M sub 1 are analyzed on the basis of equations of rotational motion in dimensionless Andoyer variables.

  4. Symmetry effects in reversible random sequential adsorption on a triangular lattice.

    Science.gov (United States)

    Budinski-Petković, Lj; Petković, M; Jaksić, Z M; Vrhovac, S B

    2005-10-01

    Reversible random sequential adsorption of objects of various shapes on a two-dimensional triangular lattice is studied numerically by means of Monte Carlo simulations. The growth of the coverage rho(t) above the jamming limit to its steady-state value rho(infinity) is described by a pattern rho(t) = rho(infinity - deltarhoE(beta)[-(t/tau)beta], where E(beta) denotes the Mittag-Leffler function of order beta element of (0, 1). The parameter tau is found to decay with the desorption probability P_ according to a power law tau = AP_(-gamma). The exponent gamma is the same for all shapes, gamma = 1.29 +/- 0.01, but the parameter A depends only on the order of symmetry axis of the shape. Finally, we present the possible relevance of the model to the compaction of granular objects of various shapes.

  5. Batched Triangular Dense Linear Algebra Kernels for Very Small Matrix Sizes on GPUs

    KAUST Repository

    Charara, Ali

    2017-03-06

    Batched dense linear algebra kernels are becoming ubiquitous in scientific applications, ranging from tensor contractions in deep learning to data compression in hierarchical low-rank matrix approximation. Within a single API call, these kernels are capable of simultaneously launching up to thousands of similar matrix computations, removing the expensive overhead of multiple API calls while increasing the occupancy of the underlying hardware. A challenge is that for the existing hardware landscape (x86, GPUs, etc.), only a subset of the required batched operations is implemented by the vendors, with limited support for very small problem sizes. We describe the design and performance of a new class of batched triangular dense linear algebra kernels on very small data sizes using single and multiple GPUs. By deploying two-sided recursive formulations, stressing the register usage, maintaining data locality, reducing threads synchronization and fusing successive kernel calls, the new batched kernels outperform existing state-of-the-art implementations.

  6. Low energy electrodynamics of triangular lattice quantum spin liquid candidate YbMgGaO4

    Science.gov (United States)

    Zhang, Xinshu; Mahmood, Fahad; Laurita, Nicholas; Dun, Zhiling; Zhou, Haidong; Mourigal, Martin; Armitage, Peter

    Quantum spin liquids (QSL) are exotic magnetic states where spins do not order down to the lowest temperatures. Spin 1/2 two-dimensional triangular antiferromagnet YbMgGaO4 is a promising QSL candidate. Here we report an optical measurement on YbMgGaO4 using time domain terahertz spectroscopy (TDTS)and Fourier transform spectroscopy (FTIR). We find the real part of in-plane dissipative response shows a power law behavior that may arise from spin liquid properties. Applying magnetic field in the Faraday geometry, we approach the spin polarized state from which we can extract g-factors and determine exchange constants quantitatively. We also identify a crystal field excitation in the infrared measurement. Our results provide guidance for the future theoretical study of this QSL.

  7. Quantum dimer model on the triangular lattice: Semiclassical and variational approaches to vison dispersion and condensation

    Science.gov (United States)

    Misguich, Grégoire; Mila, Frédéric

    2008-04-01

    After reviewing the concept of vison excitations in Z2 dimer liquids, we study the liquid-crystal transition of the quantum dimer model on the triangular lattice by means of a semiclassical spin-wave approximation to the dispersion of visons in the context of a “soft-dimer” version of the model. This approach captures some important qualitative features of the transition: continuous nature of the transition, linear dispersion at the critical point, and 12×12 symmetry-breaking pattern. In a second part, we present a variational calculation of the vison dispersion relation at the Rokhsar-Kivelson (RK) point, which reproduces the qualitative shape of the dispersion relation and the order of magnitude of the gap. This approach provides a simple but reliable approximation of the vison wave functions at the RK point.

  8. Quantum behaviour of pumped and damped triangular Bose-Hubbard systems

    Science.gov (United States)

    Chianca, C. V.; Olsen, M. K.

    2017-12-01

    We propose and analyse analogs of optical cavities for atoms using three-well Bose-Hubbard models with pumping and losses. We consider triangular configurations. With one well pumped and one damped, we find that both the mean-field dynamics and the quantum statistics show a quantitative dependence on the choice of damped well. The systems we analyse remain far from equilibrium, preserving good coherence between the wells in the steady-state. We find quadrature squeezing and mode entanglement for some parameter regimes and demonstrate that the trimer with pumping and damping at the same well is the stronger option for producing non-classical states. Due to recent experimental advances, it should be possible to demonstrate the effects we investigate and predict.

  9. Spin Structures and Phase Diagrams of Extended Spatially Completely Anisotropic Triangular Lattice Antiferromagnets

    Science.gov (United States)

    Sakakida, Keishiro; Shimahara, Hiroshi

    2017-12-01

    Motivated by recently discovered organic antiferromagnets, we examine an extended triangular lattice that consists of two types of triangles of bonds with exchange coupling constants Jℓ and J'ℓ (ℓ= 1, 2, and 3), respectively. The simplified system with Jℓ = J'ℓ > 0 is the spatially completely anisotropic triangular lattice (SCATL) antiferromagnet examined previously. The extended system, which we call an extended SCATL (ESCATL), has two different spatial anisotropy parameters J3/J2 and J'3/J'2 when J1 = J'1 is assumed. We derive classical phase diagrams and spin structures. It is found that the ESCATL antiferromagnet exhibits two up-up-down-down (uudd) phases when the imbalance of the anisotropy parameters is significant, in addition to the three Néel phases that occur in the SCATL. When the model parameters vary, these collinear phases are continuously connected by the spiral-spin phase. Using the available model parameters for the organic compounds λ-(BETS)2XCl4 (X = Fe and Ga), we examine the stabilities of the spin structures of the independent π-electron system, which is considered to primarily sustain the magnetic order, where BETS represents bis(ethylenedithio)tetraselenafulvalene. It is found that one of the uudd phases has an energy close to the ground-state energy for λ-(BETS)2FeCl4. We discuss the relevance of the magnetic anion FeCl4 and the quantum fluctuation to the magnetism of these compounds. When J'3 = 0, the system is reduced to a trellis lattice antiferromagnet. The system exhibits a stripe spiral-spin phase, which comprises one-dimensional spiral-spin states stacked alternately.

  10. Exploring the difference between Turkish and Bosnian students in Triangular Love scale

    Directory of Open Access Journals (Sweden)

    Selvira Draganović

    2015-01-01

    Full Text Available Numerous studies show that different cultures experience emotions. Some cultures tend to express emotions without restrictions while some others try to suppress the expression of emotions. These differences are particularly more manifest when Eastern and Western cultures are compared. The fact that definition of love differs between different cultures makes it difficult to determine cultural differences in the concept of love. This might serve as a basis of prejudices about some nations in relation to how they perceive love. The main aim of this study is to explore differences between Turkish and Bosnian students on love scale. The term love is operationalized by Sternberg's triangular theory of love scale which includes intimacy, passion and commitment component of love. Using quasi-experimental design we tested gender differences, the length of current relationship and correlation between them on overall scale and individual subscales. The sample consisted of 87 Turkish (22 males and 65 females and 64 Bosnian students (23 males and 41 females total 151 students (N=151. Results of the study show statistically significant differences between Turkish and Bosnian students on two dimensions in Sternberg triangular love scale intimacy and passion. Bosnian students scored higher on these subscales. Study results suggest that there is no statistically significant differences between males and females in any subscale. The length of love relationship is positively correlated with intimacy, which indicates that the length of connections weakly associated with intimacy, and that is not associated with the passion and the decision of commitment, suggesting longer relationship does not mean more romantic relationship, and vice versa

  11. Effectivity of convex triangular and rectangular cross section instruments on decreasing the amount of root canal Enterococcus faecalis bacteria colonies

    Directory of Open Access Journals (Sweden)

    Meilina Goenawan

    2016-08-01

    Full Text Available This study aims to evaluate effectiveness difference between convex triangular and rectangular cross section rotary  instruments on root canal Enterococcus faecalis bacteria colonies. Samples mandibular premolar teeth with one narrow and straight root canal divided into 3 groups : instrumented with convex triangular cross section rotary instruments, rectangular cross section rotary instruments, and convex triangular cross section manual  instruments. Each group consisted of 9 samples. Standardized teeth length, instrumented to #15 K-file  and sterilized. E. faecalis suspension in BHIB was standardized then 27 root canals contaminated. Root canals were incubated for 21 days. Every 48 hours root canals added with BHIB. Initial samples were collected, plated in agar culture medium and incubated for bacterial count. and then bacterial count was performed again. Data were collected and analysed using Paired T-test and ANOVA The results showed there are significant  difference on Enterococcus faecalis bacteria colonies amount before and after preparation with all instruments that was used and bacterial reduction amount in root canals were greater on convex triangular cross section instruments than on rectangular cross section instruments even there was no significant difference.

  12. The asc trinodal platform: Two-step assembly of triangular, tetrahedral, and trigonal-prismatic molecular building blocks

    KAUST Repository

    Schoedel, Alexander

    2013-02-10

    The self-assembly of triangular, tetrahedral, and trigonal-prismatic molecular building blocks affords the first example of a trinodal family of metal-organic materials. Four examples of isoreticular expanded and functionalized frameworks are detailed. Gas adsorption experiments validated the permanent porosity of the parent structure. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Brief Report: Intimacy, Passion, and Commitment in Romantic Relationships--Validation of a "Triangular Love Scale" for Adolescents

    Science.gov (United States)

    Overbeek, Geertjan; Ha, Thao; Scholte, Ron; de Kemp, Raymond; Engels, Rutger C. M. E.

    2007-01-01

    This study examined the psychometric properties of an adolescent version of the "triangular love scale" (TLS), which assesses three components of romantic relationships: intimacy, passion, and commitment. Using data from 435 Dutch adolescents aged 12-18 years, we found evidence for convergent validity, showing that dimensions of…

  14. Frustration-induced one-dimensionality in the isosceles triangular antiferromagnetic lattice of δ -(EDT-TTF-CONMe2)2AsF6

    Science.gov (United States)

    Náfrádi, B.; Antal, Á.; Fehér, T.; Kiss, L. F.; Mézière, C.; Batail, P.; Forró, L.; Jánossy, A.

    2016-11-01

    The 1 /4 -filled organic compound, δ -(EDT-TTF-CONMe2)2AsF6 is a frustrated two-dimensional triangular magnetic system as shown by high-frequency (111.2 and 222.4 GHz) electron spin resonance (ESR) and structural data in the literature. The material gradually orders antiferromagnetically below 40 K, but some magnetically disordered domains persist down to 4 K. We propose that in defect free regions frustration prevents true magnetic order down to at least 4 K in spite of the large first- and second-neighbor exchange interactions along chains and between chains, respectively. The antiferromagnetic (AFM) order gradually developing below 40 K nucleates around structural defects that locally cancel frustration. Two antiferromagnetic resonance modes mapped in the principal planes at 4 K are assigned to the very weakly interacting one-dimensional molecular chains in antiferromagnetic regions.

  15. The Role of Wrist Magnetic Resonance Arthrography in Diagnosing Triangular Fibrocartilage Complex Tears; Experience at King Hussein Medical Center, Jordan

    Directory of Open Access Journals (Sweden)

    Asem A. Al-Hiari

    2013-05-01

    Full Text Available Objectives: The aims of the study were to evaluate the role of magnetic resonance arthrography (MRA of the wrist in detecting full-thickness tears of the triangular fibrocartilage complex (TFCC and to compare the results of the magnetic resonance arthrography (MRA with the gold standard arthroscopic findings. Methods:The study was performed at King Hussein Medical Center, Amman, Jordan, between January 2008 and December 2011. A total of 42 patients (35 males and 7 females who had ulnar-sided wrist pain and clinical suspicions of TFCC tears were included in the study. All patients underwent wrist magnetic resonance arthrography (MRA and then a wrist arthroscopy. The results of MRA were compared with the arthroscopic findings. Results: After comparison with the arthroscopic findings, the MRA had three false-negative results (sensitivity = 93% and no false-positive results. A total of 39 patients were able to return to work. Satisfaction was high in 38 of the patients and 33 had satisfactorypain relief. The sensitivity of the wrist MRA in detecting TFCC full-thickness tears was 93% (39, and specificity was 80% (16/20. The overall accuracy of wrist arthroscopy in detecting a full-thickness tear of the TFCC in our study was 85% (29/34. Conclusion: These results illustrate the role of wrist MRA in assessing the TFCC pathology and suggest its use as the first imaging technique, following a plain X-ray, in evaluating patients with chronic ulnar side wrist pain with suspected TFCC injuries.

  16. Six new inorganic–organic hybrids based on rigid triangular ligands: Syntheses, structures and properties

    Energy Technology Data Exchange (ETDEWEB)

    Li, Na; Huang, Rudan, E-mail: huangrd@bit.edu.cn

    2016-01-15

    Six new inorganic–organic hybrids based on rigid triangular N-containing ligands, NaCu{sup I}{sub 2}(tib){sub 4}(H{sub 2}O){sub 4}[H{sub 2}PW{sup V}W{sup VI}{sub 11}O{sub 40}][H{sub 2}PW{sup VI}{sub 12}O{sub 40}]·6H{sub 2}O (1), Cu{sup II}{sub 3}(tib){sub 4}Cl{sub 4}[H{sub 2}PW{sup VI}{sub 12}O{sub 40}]{sub 2}·4H{sub 2}O (2), Co(tib){sub 2}[PW{sup V}{sub 3}W{sup VI}{sub 9}O{sub 38}]·5H{sub 2}O (3), Cu{sup II}{sub 3}(tib){sub 2}[P{sub 2}Mo{sup VI}{sub 5}O{sub 22}(O{sub 2})]·4H{sub 2}O (4), Mn(pytpy){sub 2}Mo{sup VI}{sub 4}O{sub 13} (5) and Co(pytpy){sub 2}Mo{sup VI}{sub 4}O{sub 13} (6) (tib=1,3,5-tris(1-imidazolyl)benzene, pytpy=4’-(4”-pyridyl)2,4’:6’,4”-terpyridine), have been hydrothermally synthesized. Single crystal X-ray diffraction studies revealed that compounds 1–4 display two-dimensional (2D) layered structures, and in compounds 1–3, the adjacent Keggin anions link with each other by W–O–W covalent interactions to form 1D inorganic chains. Compounds 5–6 are 3D “pillar-layer” frameworks based on bimetal–oxide layers pillared by the pytpy ligands. The compounds have been characterized by elemental analysis, powder X−ray diffraction, X-ray photoelectron spectroscopy and thermo gravimetric analyses. Moreover, the electrochemical and catalytic properties of compound 1 have been investigated as well. - Graphical abstract: Six new inorganic–organic hybrids based on rigid triangular N-containing ligands have been obtained under hydrothermal conditions and characterized by single-crystal X-ray diffraction analyses, elemental analyses, IR spectra, and thermogravimetric (TG) analyses. Compounds 1–4 display two-dimensional (2D) layers structure, and in compounds 1–3, the adjacent Keggin anions link with each other by W–O–W covalent interactions to form 1D inorganic Keggin anions chains. Compounds 5–6 are 3D “pillar-layer” frameworks based on bimetal–oxide layers pillared by the pytpy ligands. - Highlights: • MOFs

  17. Spin-Wave Analysis for Kagome-Triangular Spin System and Coupled Spin Tubes: Low-Energy Excitation for the Cuboc Order

    Science.gov (United States)

    Ochiai, Masahiro; Seki, Kouichi; Okunishi, Kouichi

    2017-11-01

    The coupled spin tube system, which is equivalent to a stacked Kagome-triangular spin system, exhibits the cuboc order — a non-coplanar spin order with a twelve-sublattice structure accompanying spontaneous breaking of the translational symmetry — in the Kagome-triangular plane. On the basis of the spin-wave theory, we analyze spin-wave excitations of the planar Kagome-triangular spin system, where the geometric phase characteristic to the cuboc spin structure emerges. We further investigate spin-wave excitations and dynamical spin structure factors for the coupled spin tubes, assuming the staggered cuboc order.

  18. Numerical investigations on the turbulent forced convection of nanofluids flow in a triangular-corrugated channel

    Directory of Open Access Journals (Sweden)

    M.A. Ahmed

    2015-09-01

    Full Text Available In this paper, turbulent forced convection of nanofluids flow in triangular-corrugated channels is numerically investigated over Reynolds number ranges of 1000–5000. Four different types of nanofluids which are Al2O3, CuO, SiO2 and ZnO–water with nanoparticles diameters in the range of 30–70 nm and the range of nanoparticles volume fraction from 0% to 4% have been considered. The governing equations of mass, momentum and energy are solved using finite volume method (FVM. The low Reynolds number k–ε model of Launder and Sharma is adopted as well. It is found that the average Nusselt number, pressure drop, heat transfer enhancement, thermal–hydraulic performance increase with increasing in the volume fraction of nanoparticles and with decreasing in the diameter of nanoparticles. Furthermore, the SiO2–water nanofluid provides the highest thermal–hydraulic performance among other types of nanofluids followed by Al2O3, ZnO and CuO–water nanofluids. Moreover, the pure water has the lowest heat transfer enhancement as well as thermal–hydraulic performance.

  19. The Enigmatic Mushtikas and the Associated Triangular Terracotta Cakes: Some Observations

    Directory of Open Access Journals (Sweden)

    J. Manuel

    2010-12-01

    Full Text Available For over four decades, now, mushtikas and its common associate, the triangular terracotta cakes have been believed to be part of ‘fire altars’. This is, in spite of the fact that, either or both of these have been found from hearths, ovens, kilns, as flooring material, on walls, in passages, streets, bathrooms and therefore obviously near commodes. Further, the great variety of central stele and construction material, size and shape, materials found within ‘fire altars’ suggest that, all the above were devoid of religious symbolism and used to achieve domestic or industrial objectives. The cakes being primarily associated with run of the mill economic activities ended up in diverse and defiling contexts. However, like many cultures across time and space Harappans may also have used the medium of fire for offering sacrifices. Therefore the existence of ‘fire altars’ is not denied as such, but these then should not have the ubiquitous cakes, at the least.

  20. Modelling plasma response to RMP fields in ASDEX Upgrade with varying edge safety factor and triangularity

    Science.gov (United States)

    Li, L.; Liu, Y. Q.; Kirk, A.; Wang, N.; Liang, Y.; Ryan, D.; Suttrop, W.; Dunne, M.; Fischer, R.; Fuchs, J. C.; Kurzan, B.; Piovesan, P.; Willensdorfer, M.; Zhong, F. C.; the ASDEX Upgrade Team; the EUROfusion MST1 Team

    2016-12-01

    Toroidal computations are performed using the MARS-F code (Liu et al 2000 Phys. Plasmas 7 3681), in order to understand correlations between the plasma response and the observed mitigation of the edge localized modes (ELM) using resonant magnetic perturbation fields in ASDEX Upgrade. In particular, systematic numerical scans of the edge safety factor reveal that the amplitude of the resonant poloidal harmonic of the response radial magnetic field near the plasma edge, as well as the plasma radial displacement near the X-point, can serve as good indicators for predicting the optimal toroidal phasing between the upper and lower rows of coils in ASDEX Upgrade. The optimal coil phasing scales roughly linearly with the edge safety factor {{q}95} , for various choices of the toroidal mode number n  =  1-4 of the coil configuration. The optimal coil phasing is also predicted to vary with the upper triangularity of the plasma shape in ASDEX Upgrade. Furthermore, multiple resonance effects of the plasma response, with continuously varying {{q}95} , are computationally observed and investigated.

  1. EPDM based double slope triangular enclosure solar collector: a novel approach.

    Science.gov (United States)

    Qureshi, Shafiq R; Khan, Waqar A; Sarwar, Waqas

    2014-01-01

    Solar heating is one of the important utilities of solar energy both in domestic and industrial sectors. Evacuated tube heaters are a commonly used technology for domestic water heating. However, increasing cost of copper and nickel has resulted in huge initial cost for these types of heaters. Utilizing solar energy more economically for domestic use requires new concept which has low initial and operating costs together with ease of maintainability. As domestic heating requires only nominal heating temperature to the range of 60-90 °C, therefore replacing nickel coated copper pipes with any cheap alternate can drastically reduce the cost of solar heater. We have proposed a new concept which utilizes double slope triangular chamber with EPDM based synthetic rubber pipes. This has reduced the initial and operating costs substantially. A detailed analytical study was carried out to design a novel solar heater. On the basis of analytical design, a prototype was manufactured. Results obtained from the experiments were found to be in good agreement with the analytical study. A maximum error of 10% was recorded at noon. However, results show that error is less than 5% in early and late hours.

  2. Trapping ultracold atoms in a sub-micron-period triangular magnetic lattice

    Science.gov (United States)

    Wang, Y.; Tran, T.; Surendran, P.; Herrera, I.; Balcytis, A.; Nissen, D.; Albrecht, M.; Sidorov, A.; Hannaford, P.

    2017-07-01

    We report the trapping of ultracold 87Rb atoms in a 0.7-μ m-period two-dimensional triangular magnetic lattice on an atom chip. The magnetic lattice is created by a lithographically patterned magnetic Co/Pd multilayer film plus bias fields. Rubidium atoms in the |F =1 , mF=-1 > low-field seeking state are trapped at estimated distances down to about 100 nm from the chip surface and with calculated mean trapping frequencies up to about 800 kHz . The measured lifetimes of the atoms trapped in the magnetic lattice are in the range 0.4-1.7 ms , depending on distance from the chip surface. Model calculations suggest the trap lifetimes are currently limited mainly by losses due to one-dimensional thermal evaporation following loading of the atoms from the Z -wire trap into the very tight magnetic lattice traps, rather than by fundamental loss processes such as surface interactions, three-body recombination, or spin flips due to Johnson magnetic noise. The trapping of atoms in a 0.7 -μ m -period magnetic lattice represents a significant step toward using magnetic lattices for quantum tunneling experiments and to simulate condensed matter and many-body phenomena in nontrivial lattice geometries.

  3. Linear Maps on Upper Triangular Matrices Spaces Preserving Idempotent Tensor Products

    Directory of Open Access Journals (Sweden)

    Li Yang

    2014-01-01

    Full Text Available Suppose m, n≥2 are positive integers. Let n be the space of all n×n complex upper triangular matrices, and let ϕ be an injective linear map on m⊗n. Then ϕ(A⊗B is an idempotent matrix in m⊗n whenever A⊗B is an idempotent matrix in m⊗n if and only if there exists an invertible matrix P∈m⊗n such that ϕ(A⊗B=P(ξ1(A⊗ξ2(BP-1,   ∀A∈m,   B∈n, or when m=n, ϕ(A⊗B=P(ξ1(B⊗ξ2(AP-1,   ∀A∈m,   B∈m, where ξ1([aij]=[aij] or ξ1([aij]=[am-i+1, m-j+1] and ξ2([bij]=[bij] or ξ2([bij]=[bn-i+1, n-j+1].

  4. The numerical investigation of heat transfer and pressure drop of turbulent flow in a triangular microchannel

    Science.gov (United States)

    Rezaei, Omid; Akbari, Omid Ali; Marzban, Ali; Toghraie, Davood; Pourfattah, Farzad; Mashayekhi, Ramin

    2017-09-01

    In this presentation, the flow and heat transfer inside a microchannel with a triangular section, have been numerically simulated. In this three-dimensional simulation, the flow has been considered turbulent. In order to increase the heat transfer of the channel walls, the semi-truncated and semi-attached ribs have been placed inside the channel and the effect of forms and numbers of ribs has been studied. In this research, the base fluid is Water and the effect of volume fraction of Al2O3 nanoparticles on the amount of heat transfer and physics of flow have been investigated. The presented results are including of the distribution of Nusselt number in the channel, friction coefficient and Performance Evaluation Criterion of each different arrangement. The results indicate that, the ribs affect the physics of flow and their influence is absolutely related to Reynolds number of flow. Also, the investigation of the used semi-truncated and semi-attached ribs in Reynolds number indicates that, although heat transfer increases, but more pressure drop arises. Therefore, in this method, in order to improve the heat transfer from the walls of microchannel on the constant heat flux, using the pump is demanded.

  5. Deconfined quantum criticality in SU(3) antiferromagnets on the triangular lattice

    Science.gov (United States)

    Pimenov, Dimitri; Punk, Matthias

    2017-05-01

    We propose field theories for a deconfined quantum critical point in SU(3) antiferromagnets on the triangular lattice. In particular we consider the continuous transition between a magnetic, three-sublattice color-ordered phase and a trimerized SU(3) singlet phase. Starting from the magnetically ordered state we derive a critical theory in terms of fractional bosonic degrees of freedom, in close analogy to the well-developed description of the SU(2) Néel—valence bond solid (VBS) transition on the square lattice. Our critical theory consists of three coupled C P2 models and we study its fixed point structure using a functional renormalization group approach in a suitable large N limit. We find a stable critical fixed point and estimate its critical exponents, thereby providing an example of deconfined criticality beyond the universality class of the C PN model. In addition we present a complementary route towards the critical field theory by studying topological defects of the trimerized SU(3) singlet phase.

  6. Artificial gauge fields in a triangular optical lattice allow for an Ising-XY phase transition

    Science.gov (United States)

    Simonet, Juliette; Struck, Julian; Weinberg, Malte; Oelschlaeger, Christoph; Hoeppner, Robert; Mathey, Ludwig; Windpassinger, Patrick; Sengstock, Klaus; Eckardt, Andre; Hauke, Philipp; Lewenstein, Maciej

    2013-05-01

    The emulation of synthetic gauge fields for ultracold atomic systems is crucial in order to access the rich physics arising when condensed matter is placed into magnetic fields. We report here on the experimental realization of gauge-invariant staggered magnetic fluxes on a periodically driven triangular lattice. The phase distribution of a superfluid submitted to π staggered fluxes obeys both the discrete Ising (Z2) and the continuous U(1) global phase symmetry. The interplay of these symmetries naturally raises the question of coupled order parameters and new universality classes of phase transitions. We analyze the behavior of the discrete and continuous order parameters measured for this two-dimensional spin-chirality coupled system. The strength of the staggered artificial gauge field is used to control the Z2 symmetry breaking, by lifting the degeneracy between the Ising states in analogy to a longitudinal homogeneous magnetic field in the standard Ising-Spin model. We observe a thermally driven Ising-type phase transition from an ordered, ferromagnetic to an unordered, paramagnetic state.

  7. Application of triangular atomic force microscopy cantilevers to friction measurement with the improved parallel scan method.

    Science.gov (United States)

    Wang, Yu-Liang; Zhao, Xue-Zeng

    2009-02-01

    The atomic force microscopy (AFM) can provide tribological information in micro/nanoscale. However, the general measurement techniques require rigorous value of stiffness and relationship between AFM cantilever deformation and corresponding photodetector response. In this study, triangular AFM cantilevers with different dimensions are applied to quantitatively measure the coefficient of friction with the improved parallel scan method [Y. L. Wang, X. Z. Zhao, and F. Q. Zhou, Rev. Sci. Instrum. 78, 036107 (2007)]. An analytical model is first presented with the plan-view geometrical dimensions of cantilevers. Finite element analysis (FEA) models are set up to validate the analytical model. The results show good agreement between analytical calculation and FEA simulation. More importantly, the coefficient of friction obtained with different cantilevers on silicon surface shows a good consistency. At last, the factors which may affect measurement are discussed. The advantage of the model presented here is that the general uncertainties of thickness and Young's modulus are not necessary to be known for the friction force calibration in AFM application.

  8. Stability evaluation of the rod in triangular array predicted by CFD

    Science.gov (United States)

    Upnere, S.; Jekabsons, N.

    2017-10-01

    Stability boundaries of structures consisting of circular cylinder arrays in the cross-flow are different from case to case depending on geometrical and mechanical variations of the rod bundle layout as well as depending on nature of the flow field, requiring an individual set of experiments for each characteristic case. In this study, close-packed staggered rod bundle with a pitch-to-diameter ratio of 1.1 is analysed. Numerical modelling has been done to check the stability threshold (critical velocity) of a flexibly mounted rod in an otherwise fixed rods array. The computational domain consists of the rod array with 6 rows of five cylinders. The unsteady flow through triangular cylinder array has been simulated using two-dimensional URANS computations with an open source Computational Fluid Dynamics (CFD) code. The CFD calculations are coupled with the six degree-of-freedom rigid body motion solver with reduced degree-of-freedom. Results were compared with the analytically determined threshold values.

  9. Frustrated mixed spin-1/2 and spin-1 Ising ferrimagnets on a triangular lattice.

    Science.gov (United States)

    Žukovič, M; Bobák, A

    2015-05-01

    Mixed spin-1/2 and spin-1 Ising ferrimagnets on a triangular lattice with sublattices A, B, and C are studied for two spin-value distributions (S(A),S(B),S(C))=(1/2,1/2,1) and (1/2,1,1) by Monte Carlo simulations. The nonbipartite character of the lattice induces geometrical frustration in both systems, which leads to the critical behavior rather different from their ferromagnetic counterparts. We confirm second-order phase transitions belonging to the standard Ising universality class occurring at higher temperatures, however, in both models these change at tricritical points (TCP) to first-order transitions at lower temperatures. In the model (1/2,1/2,1), TCP occurs on the boundary between paramagnetic and ferrimagnetic (±1/2,±1/2,∓1) phases. The boundary between two ferrimagnetic phases (±1/2,±1/2,∓1) and (±1/2,∓1/2,0) at lower temperatures is always first order and it is joined by a line of second-order phase transitions between the paramagnetic and the ferrimagnetic (±1/2,∓1/2,0) phases at a critical endpoint. The tricritical behavior is also confirmed in the model (1/2,1,1) on the boundary between the paramagnetic and ferrimagnetic (0,±1,∓1) phases.

  10. Effect of wall proximity of two staggered triangular cylinders on the transport process in a channel

    Directory of Open Access Journals (Sweden)

    Mousa Farhadi

    2016-09-01

    Full Text Available A numerical investigation has been carried out to analyze the heat transfer and the flow field around two isothermal triangular cylinders of equal size placed staggered in a horizontal plane channel with adiabatic walls. Computations have been carried out for Reynolds numbers (based on triangle width 100, 250, and 350, lateral gap ratios (d/B 0, 0.5, and 1, and longitudinal gap ratios (S/B 1, 2, 3 and 4. The effect of longitudinal and lateral gap between obstacles and proximity of channel walls is investigated. Results show that when obstacles are placed in close vicinity of the channel's wall (d/B = 1, vortex shedding disappears at the downstream of triangles at Re = 100 and 250 at all S/B, but for Re = 350 creating and disappearing of the vortex shedding depend on the longitudinal gap ratio (S/B. Proximity of obstacles has more effect on the second triangle than the first triangle especially from longitudinal gap ratio equals 2, so that with approaching the channel wall, the Nusselt number for the first triangle decreases, while for the second triangle a different behavior is seen. Staggered arrangement causes the Nusselt number of the second triangle to become greater than the first triangle.

  11. Adsorption-desorption processes of polydisperse mixtures on a triangular lattice

    Science.gov (United States)

    Dujak, D.; Lončarević, I.; Budinski-Petković, Lj.; Vrhovac, S. B.; Karač, A.

    2015-03-01

    Adsorption-desorption processes of polydisperse mixtures on a triangular lattice are studied by numerical simulations. Mixtures are composed of the shapes of different numbers of segments and rotational symmetries. Numerical simulations are performed to determine the influence of the number of mixture components and the length of the shapes making the mixture on the kinetics of the deposition process. We find that, above the jamming limit, the time evolution of the total coverage of a mixture can be described by the Mittag-Leffler function θ (t ) =θ∞-Δ θ Eβ[-(t/τ ) β] for all the mixtures we have examined. Our results show that the equilibrium coverage decreases with the number of components making the mixture and also with the desorption probability, via corresponding stretched exponential laws. For the mixtures of equal-sized objects, we propose a simple formula for predicting the value of the steady-state coverage fraction of a mixture from the values of the steady-state coverage fractions of pure component shapes.

  12. Adsorption-desorption processes of polydisperse mixtures on a triangular lattice.

    Science.gov (United States)

    Dujak, D; Lončarević, I; Budinski-Petković, Lj; Vrhovac, S B; Karač, A

    2015-03-01

    Adsorption-desorption processes of polydisperse mixtures on a triangular lattice are studied by numerical simulations. Mixtures are composed of the shapes of different numbers of segments and rotational symmetries. Numerical simulations are performed to determine the influence of the number of mixture components and the length of the shapes making the mixture on the kinetics of the deposition process. We find that, above the jamming limit, the time evolution of the total coverage of a mixture can be described by the Mittag-Leffler function θ(t)=θ∞-ΔθE[-(t/τ)β] for all the mixtures we have examined. Our results show that the equilibrium coverage decreases with the number of components making the mixture and also with the desorption probability, via corresponding stretched exponential laws. For the mixtures of equal-sized objects, we propose a simple formula for predicting the value of the steady-state coverage fraction of a mixture from the values of the steady-state coverage fractions of pure component shapes.

  13. A triangular intermuscular space sentinel node in melanoma: association with axillary lymphatic drainage.

    Science.gov (United States)

    Hennessy, Sara A; Dengel, Lynn T; Hranjec, Tjasa; Slingluff, Craig L

    2010-09-01

    Large centers have described triangular intermuscular space (TIS) sentinel nodes (SNs) for some melanomas of the back. However, their management remains controversial and poorly characterized, especially as related to the ipsilateral axillary node basin. The aim of this study was to summarize our experience with TIS SN, which may contribute to defining their appropriate surgical management. We performed a retrospective review on surgical patients from January 1993 to April 2009. Among 293 patients with upper back melanoma, data were collected on those with TIS SN. Fourteen patients (5%) with melanoma of the upper back had a TIS SN, 6 of whom (43%) were incorrectly identified at lymphoscintigraphy as axillary, and 11 of whom (79%) had a concurrent axillary SN. Micrometastatic disease was identified in TIS SN in two patients (14%) and in an axillary SN in one (9%). We found direct lymphatic drainage independently to the TIS and to the axilla, as well as a more typical pattern of drainage first to the TIS node and then to axillary nodes. We defined three patterns of lymphatic drainage to TIS and axillary nodes. The TIS and axilla are anatomically linked; patients with SN in both locations should undergo biopsies of both for optimal nodal staging. We recommend directed evaluation for TIS SN in patients with upper back melanomas and recommend clearing the TIS at the time of TIS SN biopsy. Melanoma can metastasize to TIS SN, and we discuss considerations for management of the axilla in patients with positive TIS nodes.

  14. Fast precalculated triangular mesh algorithm for 3D binary computer-generated holograms.

    Science.gov (United States)

    Yang, Fan; Kaczorowski, Andrzej; Wilkinson, Tim D

    2014-12-10

    A new method for constructing computer-generated holograms using a precalculated triangular mesh is presented. The speed of calculation can be increased dramatically by exploiting both the precalculated base triangle and GPU parallel computing. Unlike algorithms using point-based sources, this method can reconstruct a more vivid 3D object instead of a "hollow image." In addition, there is no need to do a fast Fourier transform for each 3D element every time. A ferroelectric liquid crystal spatial light modulator is used to display the binary hologram within our experiment and the hologram of a base right triangle is produced by utilizing just a one-step Fourier transform in the 2D case, which can be expanded to the 3D case by multiplying by a suitable Fresnel phase plane. All 3D holograms generated in this paper are based on Fresnel propagation; thus, the Fresnel plane is treated as a vital element in producing the hologram. A GeForce GTX 770 graphics card with 2 GB memory is used to achieve parallel computing.

  15. Triangular Alignment (TAME). A Tensor-based Approach for Higher-order Network Alignment

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Shahin [Purdue Univ., West Lafayette, IN (United States); Gleich, David F. [Purdue Univ., West Lafayette, IN (United States); Kolda, Tamara G. [Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Grama, Ananth [Purdue Univ., West Lafayette, IN (United States)

    2015-11-01

    Network alignment is an important tool with extensive applications in comparative interactomics. Traditional approaches aim to simultaneously maximize the number of conserved edges and the underlying similarity of aligned entities. We propose a novel formulation of the network alignment problem that extends topological similarity to higher-order structures and provide a new objective function that maximizes the number of aligned substructures. This objective function corresponds to an integer programming problem, which is NP-hard. Consequently, we approximate this objective function as a surrogate function whose maximization results in a tensor eigenvalue problem. Based on this formulation, we present an algorithm called Triangular AlignMEnt (TAME), which attempts to maximize the number of aligned triangles across networks. We focus on alignment of triangles because of their enrichment in complex networks; however, our formulation and resulting algorithms can be applied to general motifs. Using a case study on the NAPABench dataset, we show that TAME is capable of producing alignments with up to 99% accuracy in terms of aligned nodes. We further evaluate our method by aligning yeast and human interactomes. Our results indicate that TAME outperforms the state-of-art alignment methods both in terms of biological and topological quality of the alignments.

  16. CFD Studies on Triangular Micro-Vortex Generators in Flow Control

    Science.gov (United States)

    Yashodhar, V.; Humrutha, G.; Kaushik, M.; Khan, S. A.

    2017-03-01

    In the present study, the flow characteristics of the commercially used S809 wind turbine airfoil controlled with triangular counter-rotating micro-vortex generators at stall angle of attack of 15 degrees and 10 m/s, 15 m/s and 20 m/s (speed range used in the wind turbine applications) had been computationally investigated. In addition to the controlled airfoil, an uncontrolled airfoil was also studied for the comparison. The modelling and analysis had been carried out using incompressible, Reynolds Averaged Navier Stokes equation using Spalart-Allmaras one equation turbulence model. The numerical computations were performed with SIMPLE algorithm. The velocity profiles at different locations on the suction surface were plotted for both uncontrolled and controlled airfoils. The shear stresses exerted on the upper surface of the airfoil in both the configurations were also compared. It is found that the controlled airfoil, the shear stress distribution was greatly increased near to trailing edge of the airfoil revealing the superiority of vortex generators in increasing the efficiency of wind turbine by delaying boundary layer separation. The qualitative results of flow visualization in the spanwise direction also support the quantitative findings of velocity profiles and shear stress distribution.

  17. EPDM Based Double Slope Triangular Enclosure Solar Collector: A Novel Approach

    Directory of Open Access Journals (Sweden)

    Shafiq R. Qureshi

    2014-01-01

    Full Text Available Solar heating is one of the important utilities of solar energy both in domestic and industrial sectors. Evacuated tube heaters are a commonly used technology for domestic water heating. However, increasing cost of copper and nickel has resulted in huge initial cost for these types of heaters. Utilizing solar energy more economically for domestic use requires new concept which has low initial and operating costs together with ease of maintainability. As domestic heating requires only nominal heating temperature to the range of 60–90°C, therefore replacing nickel coated copper pipes with any cheap alternate can drastically reduce the cost of solar heater. We have proposed a new concept which utilizes double slope triangular chamber with EPDM based synthetic rubber pipes. This has reduced the initial and operating costs substantially. A detailed analytical study was carried out to design a novel solar heater. On the basis of analytical design, a prototype was manufactured. Results obtained from the experiments were found to be in good agreement with the analytical study. A maximum error of 10% was recorded at noon. However, results show that error is less than 5% in early and late hours.

  18. Streamwise counter-rotating vortices generated by triangular leading edge pattern in flat plate boundary layer

    KAUST Repository

    Hasheminejad, S. M.

    2016-01-05

    A series of flow visualizations were conducted to qualitatively study the development of streamwise counter-rotating vortices over a flat plate induced by triangular patterns at the leading edge of a flat plate. The experiments were carried out for a Reynolds number based on the pattern wavelength (λ) of 3080. The results depict the onset, development and breakdown of the vortical structures within the flat plate boundary layer. Moreover, the effect of one spanwise array of holes with diameter of 0.2λ (=3 mm) was examined. This investigation was done on two different flat plates with holes placed at the location x/λ = 2 downstream of the troughs and peaks. The presence of holes after troughs does not show any significant effect on the vortical structures. However, the plate with holes after peaks noticeably delays the vortex breakdown. In this case, the “mushroom-like” vortices move away from the wall and propagate downstream with stable vortical structures. The vortex growth is halted further downstream but start to tilt aside.

  19. Umbilicoplasty with 3 triangular skin flaps and excised diamond-shaped skin flap.

    Science.gov (United States)

    Takasu, Hidemi; Watanabe, Yoshio

    2010-10-01

    In cases of large umbilical hernias, standard surgical techniques have proven inadequate for diminishing the diameter of the umbilicus. We have modified the 3- and 4-triangular-skin-flap techniques to diminish the diameter of the umbilicus and achieve a cosmetically acceptable umbilicus. Umbilicoplasty was performed in 149 children (median age, 2.5 years; range, 3 months-10 years) between 2003 and 2008. We created 4 skin flaps 1.5 cm in length on the umbilicus and excised the cranial diamond-shaped skin flap. After closure of the fascial defect, the diameter of the umbilicus was diminished by suturing the opened cranial part of the diamond-shaped skin flap vertically. The tips of the 3 remaining flaps were then anchored to the closed fascia. Postoperatively, granulation tissue occurred in 18 cases (12%), transient erythema of a flap in 15 cases (10%), and bulging of a skin flap in 15 cases (10%). These complications were reduced by suturing adjoining skin flaps. No recurrent hernias were encountered. The postoperative umbilical appearance was satisfactory in all cases. This surgical technique is effective for diminishing the diameter of the umbilicus and creating a cosmetically acceptable shaped umbilicus, even for large umbilical hernias. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. Outcome assessment of a triangular clinic as a harm reduction intervention in Rajaee-Shahr Prison, Iran.

    Science.gov (United States)

    Asl, Rahim Taghizadeh; Eshrati, Babak; Dell, Colleen Anne; Taylor, Kelli; Afshar, Parviz; Kamali, Mohammad; Mirzazadeh, Ali

    2013-12-26

    Transmission of the human immunodeficiency virus (HIV) among incarcerated injection drug users (IDU) is a health epidemic in the Islamic Republic of Iran. Triangular clinics (TCs) were established in prisons as a harm reduction measure to decrease the risk of HIV transmission and other blood-borne infections. The objective of this study was to assess the immediate outcomes of one TC among male IDUs in Iran's Rajaee-Shahr prison. This study was conducted in two stages between 2003 and 2005. In the preparatory stage, focus group data was collected to update the prison's TC education and medical interventions and construct the self-report questionnaire. In stage two, 150 male IDUs were recruited in a closed cohort study design to assess the immediate outcome of the TC. Participants were measured at baseline and followed up to six months to measure their drug use, attitude toward and knowledge of high risk behaviours, serological conversion for HIV, HBV and HCV, and engagement in risky behaviors. The TC outcomes were determined through random urine analysis testing, a self-administered questionnaire and behaviour report cards, and viral infection testing. The findings of the urine analyses indicated a minimal yet consistent decrease in drug use over the six months. The pre and post- self-administered questionnaire data relayed a modest change in IDU risky behaviours associated with sexual practices; this was greater in comparison to the knowledge and attitude measures. It was determined that age may have a detrimental effect as may viral infections (HIV and HBV) on knowledge, attitude and behavior change. Both education and employment may have a protective effect. Data collected from the self-report behaviour cards similarly showed a modest reduction in high risk practices. At the six month follow-up, only one case became HIV positive, 9 HCV and 17 HBV. Considering that HIV is concentrated among Iranian prisoners who inject drugs at a high level, the results of this

  1. Decoherence time, hydrogenic-like impurity effect and Shannon entropy on polaron in RbCl triangular quantum dot qubit

    Science.gov (United States)

    Tiotsop, M.; Fotue, A. J.; Fautso, G. K.; Kenfack, C. S.; Fotsin, H. B.; Fai, L. C.

    2017-03-01

    Using Pekar variational method, Eigen energies of the ground and first excited states of the polaron in triangular bound and Coulomb potential quantum dot are derived in view of investigating the density of probability, the decoherence time and the Shannon entropy. Numerical analysis show that the decoherence time is decreasing function of polaron radius and the strength of the Coulombic impurity and the increase function of dispersion coefficient. These results suggest that the decrease of polaron radius and Coulombic impurity lead to the increase of coherence time. Also the entropy shows the oscillatory periodic evolution as function of the time due to the triangular form of the confinement. It's also seen that entropy is periodic for the lower value of Coulomb impurity parameter and for the higher value of the polaronic radius.

  2. Triangular step instability and 2D/3D transition during the growth of strained Ge films on Si(100)

    Energy Technology Data Exchange (ETDEWEB)

    Chen, K.M.; Jesson, D.E.; Pennycook, S.J.; Mostoller, M.; Kaplan, T.; Thundat, T.; Warmack, R.J.

    1995-04-01

    We show that an activation energy barrier exists to the formation of wavy step edges due to stress-driven 2D instability. The barrier height and the barrier width depend sensitively on the surface stress anisotropy and step free energy. The large misfit strain of Ge films significantly reduces the barrier by lowering the S{sub B} step energy, inducing S{sub A} steps to undergo a triangular instability even during low temperature growth of Ge on Si(100). The step instability results in a novel arrangement of stress domains, and the interaction between the domains causes a spatial variation of surface strain with a surprisingly large influence on the energy barrier for island nucleation. Calculations indicate a dramatic enhancement in the nucleation of 3D islands at the apex regions of triangular steps, in good agreement with our experimental measurements.

  3. Magnetotransport property of the hole-doped delafossite CuCr0.97Mg0.03O2 with a Spin-3/2 antiferromagnetic triangular sublattice

    Science.gov (United States)

    Okuda, Tetsuji; Oozono, Satoshi; Kihara, Takumi; Tokunaga, Masashi

    2013-06-01

    The magnetotransport property of a hole-doped delafossite CuCr0.97Mg0.03O2 with a spin-3/2 antiferromagnetic (AF) triangular sublattice was investigated by using a pulsed high magnetic field. A dramatic change of magnetoresistance was observed with a variation of temperature, which indicates that a spin fluctuation due to a competition between the AF and the ferromagnetic Hund's interactions is enhanced at temperatures around the Néel temperatures ( T N). The competition may lead to a partially-disordered state at temperatures below T N which may cause a nontrivial promotion of a 120° Néel state.

  4. Localized spin-wave modes in a triangular magnetic element studied by micro-focused Brillouin light scattering

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, S.; Kwon, J.-H. [School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Grünberg, P. [Grünberg Center for Magnetic Nanomaterials, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Cho, B.K., E-mail: chobk@gist.ac.kr [School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of)

    2017-09-01

    Highlights: • Direct evidence of localized mode in a triangular nano-magnet using μ-BLS. • Localized regions are identified by the internal field distribution. • The spatially resolved measurement was performed to obtain 2-D intensity map. • Spin modes in same positions can be distinguish comparing with simulated spectrum. • Localized modes were identified by comparing with the simulated spatial profiles. - Abstract: Localized spin-wave modes, which were thermally excited at a specific position in a triangular magnetic element, were investigated using micro-focused Brillouin light scattering in two saturated states, the buckle and Y-states, with an applied magnetic field of 0.24 T parallel and perpendicular to the basal edge, respectively. The measured frequency spectrum at a specific beam spot position, rather than an integrated spectrum, was analyzed by comparing it with the simulation data at a precisely selected position within the beam spot area. The analyzed results were used to plot a two-dimensional intensity map and simulation spatial profile to verify the validity of the analysis. From the analysis process, two localized spin-wave modes in a triangular magnetic element were successfully identified near the apex region in the buckle state and near the basal edge region in the Y-state.

  5. Effect of Refractive Index of Substrate on Fabrication and Optical Properties of Hybrid Au-Ag Triangular Nanoparticle Arrays

    Directory of Open Access Journals (Sweden)

    Jing Liu

    2015-05-01

    Full Text Available In this study, the nanosphere lithography (NSL method was used to fabricate hybrid Au-Ag triangular periodic nanoparticle arrays. The Au-Ag triangular periodic arrays were grown on different substrates, and the effect of the refractive index of substrates on fabrication and optical properties was systematically investigated. At first, the optical spectrum was simulated by the discrete dipole approximation (DDA numerical method as a function of refractive indexes of substrates and mediums. Simulation results showed that as the substrates had the refractive indexes of 1.43 (quartz and 1.68 (SF5 glass, the nanoparticle arrays would have better refractive index sensitivity (RIS and figure of merit (FOM. Simulation results also showed that the peak wavelength of the extinction spectra had a red shift when the medium’s refractive index n increased. The experimental results also demonstrated that when refractive indexes of substrates were 1.43 and 1.68, the nanoparticle arrays and substrate had better adhesive ability. Meanwhile, we found the nanoparticles formed a large-scale monolayer array with the hexagonally close-packed structure. Finally, the hybrid Au-Ag triangular nanoparticle arrays were fabricated on quartz and SF5 glass substrates and their experiment extinction spectra were compared with the simulated results.

  6. A CPW-Fed UWB Antenna with C-band/WLAN/X-band Notch Functions using Isosceles Triangular Resonator and Stepped Impedance Resonator

    National Research Council Canada - National Science Library

    Yingsong Li; Chengyuan Liu; Fang Fu; Xiaodong Yang; Tao Jiang

    2012-01-01

    ... stub in the CPW fed transmission line. The two notched bands can be tuned by changing the dimensions of isosceles triangular, stepped impedance resonator and the inner stubs to give tunable notched band functions...

  7. Six new inorganic-organic hybrids based on rigid triangular ligands: Syntheses, structures and properties

    Science.gov (United States)

    Li, Na; Huang, Rudan

    2016-01-01

    Six new inorganic-organic hybrids based on rigid triangular N-containing ligands, NaCuI2(tib)4(H2O)4[H2PWVWVI11O40][H2PWVI12O40]·6H2O (1), CuII3(tib)4Cl4[H2PWVI12O40]2·4H2O (2), Co(tib)2[PWV3WVI9O38]·5H2O (3), CuII3(tib)2[P2MoVI5O22(O2)]·4H2O (4), Mn(pytpy)2MoVI4O13 (5) and Co(pytpy)2MoVI4O13 (6) (tib=1,3,5-tris(1-imidazolyl)benzene, pytpy=4'-(4;-pyridyl)2,4':6',4;-terpyridine), have been hydrothermally synthesized. Single crystal X-ray diffraction studies revealed that compounds 1-4 display two-dimensional (2D) layered structures, and in compounds 1-3, the adjacent Keggin anions link with each other by W-O-W covalent interactions to form 1D inorganic chains. Compounds 5-6 are 3D ;pillar-layer; frameworks based on bimetal-oxide layers pillared by the pytpy ligands. The compounds have been characterized by elemental analysis, powder X-ray diffraction, X-ray photoelectron spectroscopy and thermo gravimetric analyses. Moreover, the electrochemical and catalytic properties of compound 1 have been investigated as well.

  8. Visual determination of trace cysteine based on promoted corrosion of triangular silver nanoplates by sodium thiosulfate.

    Science.gov (United States)

    Hou, Xin Yan; Chen, Shu; Tang, Jian; Long, Yun Fei

    2014-05-05

    In this study, triangular silver nanoplates (TAg-NPs) were used to detect trace Cysteine concentration in the presence of sodium thiosulfate (Na2S2O3). Study showed that the TAg-NPs could be gently etched by Cysteine with the concentration of 1.0×10(-7) mol L(-1) through forming Ag-S covalent bond at the three corners. However, in the presence of Na2S2O3 (only 3.0×10(-6) mol L(-1)), the corrosion of Cysteine on TAg-NPs can be promoted significantly. It was also found that the color, morphology, and the maximum absorption wavelength of TAg-NPs change clearly with the concentrations of Cysteine as low as 2.5×10(-8) mol L(-1). Furthermore, the wavelength shift values (Δλ) of TAg-NPs solution were proportional to the concentrations of Cysteine in the range of 1.0×10(-9)-1.0×10(-7) mol L(-1), and the linear regression equation is Δλ=-0.89+319.94 c (c, μM, n=5) with the correlation coefficient of 0.990. At the same time, the color change of the TAg-NPs solution could be observed clearly by the naked eyes with increasing Cysteine concentrations in the range of 2.5×10(-8)-1.0×10(-7) mol L(-1). Thus, a novel method for the detection of Cysteine by either UV-vis spectrophotometry detection or naked eyes observation is established. It allows determination of Cysteine content in compound amino acid injection sample of 18AA-V. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Meniscus and discus lesions of triangular fibrocartilage complex (TFCC): treatment by laser-assisted wrist arthroscopy.

    Science.gov (United States)

    Infanger, Manfred; Grimm, Daniela

    2009-04-01

    Meniscus and disc lesions in the triangular fibrocartilage complex (TFCC) are generally caused by falling accidents with pronated, hyperextended wrists, or by distraction injuries that pull the ulnar side of the wrist out of place. Characteristic clinical signs are swelling and pain in the distal radioulnar joint (DRUJ) and a 'clicking' noise in the meniscus lesion. If untreated, loss of mobility and grip strength as well as progressive arthritic changes ensue. We investigated in this study the laser-assisted arthroscopic debridement of the central TFCC and meniscus to compare the advantages and disadvantages of such treatment to conventional arthroscopic debridement. Seventy-two patients underwent laser-assisted arthroscopic debridement of traumatic TFCC tears (meniscus and disc). Patients with TFCC tears that were associated with fractures, significant bone or neurovascular pathology or DRUJ instability were excluded from the study. The mean age was 32.4 years; 28 female and 51 male patients were included in the study. The mean follow up was 25.6 months. First of all, we evaluated the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. We then applied the range of motion of the hand (ROM) as second variable during statistical analysis to identify outcome. There were no complications after surgery. No instabilities or dislocations of the DRUJ were noted. The postoperative DASH score indicated that the laser-assisted arthroscopic repair of traumatic peripheral TFCC tears resulted in a very good functional outcome. All patients with isolated meniscus homologue tears were without pain after the operation. At final follow up, the ROM was equal to or greater than that of the contralateral side. We have demonstrated that the TFCC laser debridement technique is easy and safe to perform. The outcome was excellent with less pain and good ROM. In particular, the laser technique enabled a good intra-articular haemostasis and allowed an exact tear debridement.

  10. [Arthroscopically assisted transcapsular refixation of the triangular fibrocartilage complex of the wrist].

    Science.gov (United States)

    Pillukat, T; Fuhrmann, R A; Windolf, J; van Schoonhoven, J

    2016-08-01

    Refixation of the triangular fibrocartilage complex (TFCC) to the ulnar capsule of the wrist. Distal TFCC tears without instability, proximal TFCC intact. Loose ulnar TFCC attachment without tear or instability. Peripheral TFCC tears with instability of the distal radioulnar joint (DRUJ). Complex or proximal tears of the TFCC. Isolated, central degenerative tears without healing potential. Arthroscopically guided, minimally invasive suture of the TFCC to the base of the sixth extensor compartment. Above elbow plaster splint, 70° flexion of the elbow joint, 45° supination for 6 weeks. Skin suture removal after 2 weeks. No physiotherapy to extend pronation and supination during the first 3 months. In an ongoing long-term study, 7 of 31 patients who underwent transcapsular refixation of the TFCC between 1 January 2003 and 31 December 2010 were evaluated after an average follow-up interval of 116 ± 34 months (range 68-152 months). All patients demonstrated an almost nearly unrestricted range of wrist motion and grip strength compared to the unaffected side. All distal radioulnar joints were stable. On the visual analogue scale (VAS 0-10), pain at rest was 1 ± 1 (range 0-2) and pain during exercise 2 ± 2 (range 0-5); the DASH score averaged 10 ± 14 points (range 0-39 points). All patients were satisfied. The modified Mayo wrist score showed four excellent, two good, and one fair result. These results correspond to the results of other series. Transcapsular refixation is a reliable, technically simple procedure in cases with ulnar-sided TFCC tears without instability leading to good results.

  11. Versão abreviada da Escala Triangular do Amor: evidências de validade fatorial e consistência interna Brief version of the Triangular Love Scale: evidences of factor validity and reliability

    Directory of Open Access Journals (Sweden)

    Valdiney Veloso Gouveia

    2009-04-01

    Full Text Available O presente estudo teve como objetivo conhecer os parâmetros psicométricos de uma versão reduzida da Escala Triangular do Amor. Especificamente, procurou-se reunir evidências de sua validade fatorial e consistência interna no contexto paraibano. Participaram 307 estudantes universitários da cidade de João Pessoa (PB, que mantinham um relacionamento heterossexual estável, com idade média de 23,4 anos (dp = 6,22; amplitude de 17 a 56 anos. A maioria foi do sexo feminino (69,4% e solteira (73%. Os participantes responderam a Escala Triangular do Amor e perguntas demográficas. Os resultados apoiaram a adequação psicométrica dessa medida, que apresentou três componentes (rotação varimax; explicando 67,7% da variância total, com Alfas de Cronbach satisfatórios: compromisso (α = 0,88, paixão (α = 0,87 e intimidade (α = 0,86. As mulheres pontuaram mais em compromisso do que fizeram os homens. Estes resultados foram discutidos à luz da literatura, confirmando-se a adequação desta medida. Pesquisas futuras foram sugeridas.This study aimed at knowing the psychometric parameters of a shorted version of the Triangular Love Scale. Specifically, it tried to joint evidences of its factor validity and reliability in the Paraibano milieu. Participants were 307 undergraduate students from João Pessoa (PB, which have a stable heterosexual relationship. Their mean age was 23.4 years old (sd = 6.22; ranging from 17 to 56, most of them female (69.4% and single (73%. They answered the Triangular Love Scale and demographic asks. Results support the psychometric adequacy of this measure, which showed three components (varimax rotation; accounting for 67.7% of the total variance, with satisfactory Cronbach's Alpha: commitment (α = 0.88, passion (α = 0.87, and intimacy (α = 0.86. Women scored higher than men in commitment. These findings were discussed based on literature, confirming the adequacy of the scale. Future studies were suggested too.

  12. The great triangular seismic region in eastern Asia: Thoughts on its dynamic context

    Directory of Open Access Journals (Sweden)

    Xianglin Gao

    2011-01-01

    Full Text Available A huge triangle-shaped tectonic region in eastern Asia plays host to numerous major earthquakes. The three boundaries of this region, which contains plateaus, mountains, and intermountain basins, are roughly the Himalayan arc, the Tianshan-Baikal, and longitude line ∼105°E. Within this triangular region, tectonism is intense and major deformation occurs both between crustal blocks and within most of them. Outside of this region, rigid blocks move as a whole with relatively few major earthquakes and relatively weak Cenozoic deformation. On a large tectonic scale, the presence of this broad region of intraplate deformation results from dynamic interactions between the Indian, Philippine Sea-West Pacific, and Eurasian plates, as well as the influence of deep-level mantle flow. The Indian subcontinent, which continues to move northwards at ∼40 mm/a since its collision with Eurasia, has plunged beneath Tibet, resulting in various movements and deformations along the Himalayan arc that diffuse over a long distance into the hinterland of Asia. The northward crustal escape of Asia from the Himalayan collisional zone turns eastwards and southeastwards along 95°–100°E longitude and defines the eastern Himalayan syntaxis. At the western Himalayan syntaxis, the Pamirs continue to move into central Asia, leading to crustal deformation and earthquakes that are largely accommodated by old EW or NW trending faults in the bordering areas between China, Mongolia, and Russia, and are restricted by the stable landmass northwest of the Tianshan-Altai-Baikal region. The subduction of the Philippine and Pacific plates under the Eurasian continent has generated a very long and narrow seismic zone along trenches and island arcs in the marginal seas while imposing only slight horizontal compression on the Asian continent that does not impede the eastward motion of eastern Asia. In the third dimension, there may be southeastward deep mantle flow beneath most of

  13. The R package 'icosa' for coarse resolution global triangular and penta-hexagonal gridding

    Science.gov (United States)

    Kocsis, Adam T.

    2017-04-01

    With the development of the internet and the computational power of personal computers, open source programming environments have become indispensable for science in the past decade. This includes the increase of the GIS capacity of the free R environment, which was originally developed for statistical analyses. The flexibility of R made it a preferred programming tool in a multitude of disciplines from the area of the biological and geological sciences. Many of these subdisciplines operate with incidence (occurrence) data that are in a large number of cases to be grained before further analyses can be conducted. This graining is executed mostly by gridding data to cells of a Gaussian grid of various resolutions to increase the density of data in a single unit of the analyses. This method has obvious shortcomings despite the ease of its application: well-known systematic biases are induced to cell sizes and shapes that can interfere with the results of statistical procedures, especially if the number of incidence points influences the metrics in question. The 'icosa' package employs a common method to overcome this obstacle by implementing grids with roughly equal cell sizes and shapes that are based on tessellated icosahedra. These grid objects are essentially polyhedra with xyz Cartesian vertex data that are linked to tables of faces and edges. At its current developmental stage, the package uses a single method of tessellation which balances grid cell size and shape distortions, but its structure allows the implementation of various other types of tessellation algorithms. The resolution of the grids can be set by the number of breakpoints inserted into a segment forming an edge of the original icosahedron. Both the triangular and their inverted penta-hexagonal grids are available for creation with the package. The package also incorporates functions to look up coordinates in the grid very effectively and data containers to link data to the grid structure. The

  14. Coupling-governed metamorphoses of the integrable nonlinear Schrödinger system on a triangular-lattice ribbon

    Energy Technology Data Exchange (ETDEWEB)

    Vakhnenko, Oleksiy O., E-mail: vakhnenko@bitp.kiev.ua

    2016-05-27

    Highlights: • The integrable nonlinear Schrödinger system on a triangular-lattice ribbon is inclined to metamorphoses. • The system under study is capable to incorporate the effect of external linear potential. • The system criticality against the background parameter reduces the number of independent field variables. • At critical point the system Poisson structure becomes degenerate. • The effect of criticality is elucidated by the system one-soliton solution. - Abstract: The variativity of governing coupling parameters in the integrable nonlinear Schrödinger system on a triangular-lattice ribbon is shown to ensure the important qualitative rearrangements in the system dynamics. There are at least the two types of system crucial modifications stipulated by the two types of governing parameters. Thus the longitudinal coupling parameters regulated mainly by the background values of concomitant field variables are responsible for the bifurcation of primary integrable nonlinear system into the integrable nonlinear system of Ablowitz–Ladik type. As a consequence in a critical point the number of independent field variables is reduced by a half and the system Poisson structure turns out to be degenerate. On the other hand the transverse coupling parameters regulated basically by the choice of their a priori arbitrary dependencies on time are capable to incorporate the effect of external linear potential. As a consequence the primary integrable nonlinear system with appropriately adjusted parametrical driving becomes isomorphic to the system modeling the Bloch oscillations of charged nonlinear carriers in an electrically biased ribbon of triangular lattice. The multi-component structure of basic integrable system alongside with the attractive character of system nonlinearities has predetermined the logic of whole consideration.

  15. Subspace-Based Noise Reduction for Speech Signals via Diagonal and Triangular Matrix Decompositions: Survey and Analysis

    Directory of Open Access Journals (Sweden)

    Søren Holdt Jensen

    2007-01-01

    Full Text Available We survey the definitions and use of rank-revealing matrix decompositions in single-channel noise reduction algorithms for speech signals. Our algorithms are based on the rank-reduction paradigm and, in particular, signal subspace techniques. The focus is on practical working algorithms, using both diagonal (eigenvalue and singular value decompositions and rank-revealing triangular decompositions (ULV, URV, VSV, ULLV, and ULLIV. In addition, we show how the subspace-based algorithms can be analyzed and compared by means of simple FIR filter interpretations. The algorithms are illustrated with working Matlab code and applications in speech processing.

  16. Algebraic vortex liquid in spin-1/2 triangular antiferromagnets: Scenario for Cs_2CuCl_4

    OpenAIRE

    Alicea, Jason; Motrunich, Olexei I.; Fisher, Matthew P. A.

    2005-01-01

    Motivated by inelastic neutron scattering data on Cs_2CuCl_4, we explore spin-1/2 triangular lattice antiferromagnets with both spatial and easy-plane exchange anisotropies, the latter due to an observed Dzyaloshinskii-Moriya interaction. Exploiting a duality mapping followed by a fermionization of the dual vortex degrees of freedom, we find a novel "critical" spin-liquid phase described in terms of Dirac fermions with an emergent global SU(4) symmetry minimally coupled to a non-compact U(1) ...

  17. Control of optical bistability and third-order nonlinearity via tunneling induced quantum interference in triangular quantum dot molecules

    Directory of Open Access Journals (Sweden)

    Si-Cong Tian

    2015-06-01

    Full Text Available The optical bistability of a triangular quantum dot molecules embedded inside a unidirectional ring cavity is studied. The type, the threshold and the hysteresis loop of the optical bistability curves can be modified by the tunneling parameters, as well as the probe laser field. The linear and nonlinear susceptibilities of the medium are also studied to interpret the corresponding results. The physical interpretation is that the tunneling can induce the quantum interference, which modifies the linear and the nonlinear response of the medium. As a consequence, the characteristics of the optical bistability are changed. The scheme proposed here can be utilized for optimizing and controlling the optical switching process.

  18. The effect of electromagnetic field and Coulomb impurity on polaron in RbCl triangular quantum dot qubit

    Science.gov (United States)

    Tiotsop, M.; Fotue, A. J.; Kenfack, S. C.; Fotsin, H. B.; Fai, L. C.

    2016-09-01

    In the following study, the time evolution of the quantum mechanical state of a magnetopolaron using the Pekar type variational method on the electric-LO-phonon was considered. A strong coupling of polaron in triangular RbCl quantum dot with Coulomb impurity was duly derived. The Eigen energies and the Eigen functions of the ground state and the first excited state were obtained respectively. The obtained system in a quantum dot was treated as a two-level quantum system qubit and the numerical calculations were performed. The relations of polaron life time, the probability density, the Coulomb binding parameter and the polar angle were derived.

  19. Achievement of Fundamental Rights by Individual Initiative: Brazil in Relation to European Paradigm of “Triangular Basis Constitutional Justice”

    Directory of Open Access Journals (Sweden)

    Ana Angelica Moreira Ribeiro Lima

    2016-10-01

    Full Text Available The current legal and qualitative dogmatic study makes use of the deductive method, exploratory and descriptive focus, bibliographical and documentary survey and content analysis to compare forms of achievement of fundamental rights in the Brazilian and European contexts. It’s concluded that the European “triangular basis constitutional justice”, in which there are three judicial guardianship systems, the European Court of Human Rights, member states courts and the European Union courts, provides greater safekeeping to fundamental rights of individual protection because of their simplicity, accessibility and assertiveness, tasking propose alternatives of implementation and enforcement of such rights in the national legal order.

  20. Self-organization of topological defects for a triangular-lattice magnetic dots array subject to a perpendicular magnetic field

    Directory of Open Access Journals (Sweden)

    R.S. Khymyn

    2014-09-01

    Full Text Available The regular array of magnetic particles (magnetic dots of the form of a two-dimensional triangular lattice in the presence of external magnetic field demonstrates complicated magnetic structures. The magnetic symmetry of the ground state for such a system is lower than that for the underlying lattice. Long range dipole-dipole interaction leads to a specific antiferromagnetic order in small fields, whereas a set of linear topological defects appears with the growth of the magnetic field. Self-organization of such defects determines the magnetization process for a system within a wide range of external magnetic fields.

  1. Thermo-Elastic Triangular Sandwich Element for the Complete Stress Field Based on a Single-Layer Theory

    Science.gov (United States)

    Das, M.; Barut, A.; Madenci, E.; Ambur, D. R.

    2004-01-01

    This study presents a new triangular finite element for modeling thick sandwich panels, subjected to thermo-mechanical loading, based on a {3,2}-order single-layer plate theory. A hybrid energy functional is employed in the derivation of the element because of a C interelement continuity requirement. The single-layer theory is based on five weighted-average field variables arising from the cubic and quadratic representations of the in-plane and transverse displacement fields, respectively. The variations of temperature and distributed loading acting on the top and bottom surfaces are non-uniform. The temperature varies linearly through the thickness.

  2. Measurement and analysis of flow wall shear stress in an interior subchannel of triangular array rods. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Fakori-Monazah, M.R.; Todreas, N.E.

    1977-08-01

    A simulated model of triangular array rods with pitch to diameter ratio of 1.10 (as a test section) and air as the fluid flow was used to study the LMFBR hydraulic parameters. The wall shear stress distribution around the rod periphery, friction factors, static pressure distributions and turbulence intensity corresponding to various Reynolds numbers ranging from 4140 to 36170 in the central subchannel were measured. Various approaches for measurement of wall shear stress were compared. The measurement was performed using the Preston tube technique with the probe outside diameter equal to 0.014 in.

  3. Spin Nematics, Valence-Bond Solids, and Spin Liquids in SO(N) Quantum Spin Models on the Triangular Lattice.

    Science.gov (United States)

    Kaul, Ribhu K

    2015-10-09

    We introduce a simple model of SO(N) spins with two-site interactions which is amenable to quantum Monte Carlo studies without a sign problem on nonbipartite lattices. We present numerical results for this model on the two-dimensional triangular lattice where we find evidence for a spin nematic at small N, a valence-bond solid at large N, and a quantum spin liquid at intermediate N. By the introduction of a sign-free four-site interaction, we uncover a rich phase diagram with evidence for both first-order and exotic continuous phase transitions.

  4. Colgajo miocutáneo de gastrocnemius medial con isla triangular de piel y cierre en V-Y

    OpenAIRE

    CALDERÓN O,WILFREDO; SPRÖHNLE F,VIVIANA; Las Heras F,Rocío; LLANOS O,SERGIO; Calderón M,Daniel

    2009-01-01

    Para corregir defectos cutáneos con exposición de fractura de tibia a nivel del tercio proximal, una buena alternativa es el colgajo miocutáneo de gastrocnemius medial con isla triangular de piel con cierre en V-Y. Las ventajas estriban en la excelente irrigación del colgajo, y en proporcionar un cierre cutáneo con colgajo, en una zona expuesta a múltiples traumatismos. El hecho de tener una perforante arterio venosa previamente ubicada con doppler color, asegura la vitalidad del colgajo. Se ...

  5. A New Improved Variable Frequency Triangular Carrier-PWM with MOPSO Algorithm for Carrier Based PWM Techniques in Inverters

    Directory of Open Access Journals (Sweden)

    Mohammad Sadegh Orfi Yegane

    2017-02-01

    Full Text Available This paper investigates multi-carrier PWM methods in multi-level inverters. Two new MCPWM methods are introduced. This study proposes a new optimized MCPWM method to improve the output voltage characteristics like THD and LOH. The proposed method is based on variable frequency with a specific range. It means each carrier wave has a determined frequency. It is calling Variable Frequency Triangular Carrier-PWM. MOPSO algorithm is used to optimize the answers. This work considers some different levels of inverters like five, seven and nine levels. The results are compared with SPWM method.

  6. Thermal Transport and Magnetotransport Properties of CuCr1-xMgxO2 with a Spin-3/2 Antiferromagnetic Triangular Lattice

    Science.gov (United States)

    Okuda, Tetsuji; Oozono, Satoshi; Kihara, Takumi; Tokunaga, Masashi

    2013-01-01

    We have investigated the thermal conductivity (κ) and magnetoresistance (MR) of non-doped and hole-doped delafossite CuCrO2 with a spin-3/2 antiferromagnetic (AF) triangular sublattice. The phonon mean free path above the Néel temperature (TN) deduced from κ and lattice specific heat is almost identical to the magnetic correlation length, which indicates that, for both compounds, spin fluctuation enhanced in a geometrically frustrated lattice is strongly coupled with acoustic phonon above TN. κ below TN is significantly suppressed by Mg substitution, suggesting the introduction of some disorder into the 120° Néel state. For the hole-doped CuCr0.97Mg0.03O2, a negative MR is observed above TN, which is enhanced with a decrease in T toward TN, while a component of positive MR appears below TN and the residual negative MR component is observed in a high magnetic field, indicating that spin fluctuation coupled with electrical conductivity is critically enhanced above TN and remains below TN. These results evidence that the 120° Néel state is partially disordered by a doped itinerant hole coupled with spin fluctuation, although AF transition is certainly promoted. The dynamic partial disorder may stabilize the Néel order through an order-by-disorder mechanism.

  7. Normalization of Hamiltonian and nonlinear stability of the triangular equilibrium points in non-resonance case with perturbations

    Science.gov (United States)

    Kishor, Ram; Kushvah, Badam Singh

    2017-09-01

    For the study of nonlinear stability of a dynamical system, normalized Hamiltonian of the system is very important to discuss the dynamics in the vicinity of invariant objects. In general, it represents a nonlinear approximation to the dynamics, which is very helpful to obtain the information as regards a realistic solution of the problem. In the present study, normalization of the Hamiltonian and analysis of nonlinear stability in non-resonance case, in the Chermnykh-like problem under the influence of perturbations in the form of radiation pressure, oblateness, and a disc is performed. To describe nonlinear stability, initially, quadratic part of the Hamiltonian is normalized in the neighborhood of triangular equilibrium point and then higher order normalization is performed by computing the fourth order normalized Hamiltonian with the help of Lie transforms. In non-resonance case, nonlinear stability of the system is discussed using the Arnold-Moser theorem. Again, the effects of radiation pressure, oblateness and the presence of the disc are analyzed separately and it is observed that in the absence as well as presence of perturbation parameters, triangular equilibrium point is unstable in the nonlinear sense within the stability range 0study may help to analyze more generalized cases of the problem in the presence of some other types of perturbations such as P-R drag and solar wind drag. The results are limited to the regular symmetric disc but it can be extended in the future.

  8. Bio-synthesis of triangular and hexagonal gold nanoparticles using palm oil fronds’ extracts at room temperature

    Science.gov (United States)

    Usman, Adamu Ibrahim; Aziz, Azlan Abdul; Abu Noqta, Osama

    2018-01-01

    Development of bio-reduction techniques for nanoparticles (NPs) synthesis in medical application remains a challenge to numerous researchers. This work reports a novel technique for the synthesis of triangular and hexagonal gold nanoparticles (AuNP) using palm oil fronds’ (POFs) extracts. The functional groups in the POFs’ extracts operate as a persuasive capping and reducing agent to growth AuNPs. The prepared AuNPs were characterized using UV–vis spectrophotometry, Fourier-transform infrared (FTIR) spectroscopy, dynamic light scattering, energy filtered transmission electron microscopy (EFTEM), and x-ray diffraction (XRD). The analysis of FTIR validates the coating of alkynes and phenolic composites on the AuNPs. This shows a feasible function of biomolecules for efficient stabilization of the AuNPs. EFTEM clearly show the triangular and hexagonal shapes of the prepared AuNPs. The XRD patterns display the peaks of fcc crystal structures at (111), (200), (220), (311) and (222), with average particle sizes of 66.7 and 79.02 nm for 1% and 5% POFs extracts concentrations respectively at room temperature. While at 120 °C the average particles size recorded for 1% and 5% of POFs extract concentrations were 32.17 nm and 45.66 nm respectively, and the reaction completed in less than 2 min. The prepared NPs could be potentially applied in biomedical application, due to their excellent stability and refine morphology without agglomeration.

  9. The effects of the depth of web on the bending behaviour of triangular web profile steel beam section

    Science.gov (United States)

    De'nan, Fatimah; Keong, Choong Kok; Hashim, Nor Salwani

    2017-10-01

    Due to extensive usage of corrugated web in construction, this paper performs finite element analysis to investigate the web thickness effects on the bending behaviour of Triangular Web Profile (TRIWP) steel section. A TRIWP steel section which are consists two flanges attached to a triangular profile web plate. This paper analyzes two categories of TRIWP steel sections which are D×100×6×3 mm and D×75×5×2 mm. It was observed that for steel section D×100×6×3 mm (TRIWP1), the deflection about minor and major axis increased as the span length increased. Meanwhile, the deflection about major axis decreased when depth of the web increased. About minor axis, the deflection increased for 3m and 4m span, while the deflection at 4.8m decreased with increment the depth of web. However, when the depth of the web exceeds 250mm, deflection at 3m and 4m were increased. For steel section D×75×5×2 mm (TRIWP2), the result was different with TRIWP1 steel section, where the deflection in both major and minor directions increased with the increment of span length and decreased with increment the depth of web. It shows that the deflection increased proportionally with the depth of web. Therefore, deeper web should be more considered because it resulted in smaller deflection.

  10. A Self-Oscillating System to Measure the Conductivity and the Permittivity of Liquids within a Single Triangular Signal

    Directory of Open Access Journals (Sweden)

    Sylvain Druart

    2014-01-01

    Full Text Available We present a methodology and a circuit to extract liquid resistance and capacitance simultaneously from the same output signal using interdigitated sensing electrodes. The principle consists in the generation of a current square wave and its application to the sensor to create a triangular output voltage which contains both the conductivity and permittivity parameters in a single periodic segment. This concept extends the Triangular Waveform Voltage (TWV signal generation technique and is implemented by a system which consists in a closed-loop current-controlled oscillator and only requires DC power to operate. The system interface is portable and only a small number of electrical components are used to generate the expected signal. Conductivities of saline NaCl and KCl solutions, being first calibrated by commercial equipment, are characterized by a system prototype. The results show excellent linearity and prove the repeatability of the measurements. Experiments on water-glycerol mixtures validate the proposed sensing approach to measure the permittivity and the conductivity simultaneously. We discussed and identified the sources of measurement errors as circuit parasitic capacitances, switching clock feedthrough, charge injection, bandwidth, and control-current quality.

  11. Structural Performance of a Hybrid FRP-Aluminum Modular Triangular Truss System Subjected to Various Loading Conditions

    Directory of Open Access Journals (Sweden)

    Dongdong Zhang

    2014-01-01

    Full Text Available A novel hybrid FRP-aluminum truss system has been employed in a two-rut modular bridge superstructure composed of twin inverted triangular trusses. The actual flexural behavior of a one-rut truss has been previously investigated under the on-axis loading test; however, the structural performance of the one-rut truss subjected to an off-axis load is still not fully understood. In this paper, a geometrical linear finite element model is introduced and validated by the on-axis loading test; the structural performance of the one-rut truss subjected to off-axis load was numerically obtained; the dissimilarities of the structural performance between the two different loading cases are investigated in detail. The results indicated that (1 the structural behavior of the off-axis load differs from that of the on-axis load, and the off-axis load is the critical loading condition controlling the structural performance of the triangular truss; (2 under the off-axis load, the FRP trussed members and connectors bear certain out-of-plane bending moments and are subjected to a complicated stress state; and (3 the stress state of these members does not match that of the initial design, and optimization for the redesign of these members is needed, especially for the pretightened teeth connectors.

  12. Some calculator programs for particle physics. [LEGENDRE, ASSOCIATED LEGENDRE, CONFIDENCE, TWO BODY, ELLIPSE, DALITZ RECTANGULAR, and DALITZ TRIANGULAR codes

    Energy Technology Data Exchange (ETDEWEB)

    Wohl, C.G.

    1982-01-01

    Seven calculator programs that do simple chores that arise in elementary particle physics are given. LEGENDRE evaluates the Legendre polynomial series ..sigma..a/sub n/P/sub n/(x) at a series of values of x. ASSOCIATED LEGENDRE evaluates the first-associated Legendre polynomial series ..sigma..b/sub n/P/sub n//sup 1/(x) at a series of values of x. CONFIDENCE calculates confidence levels for chi/sup 2/, Gaussian, or Poisson probability distributions. TWO BODY calculates the c.m. energy, the initial- and final-state c.m. momenta, and the extreme values of t and u for a 2-body reaction. ELLIPSE calculates coordinates of points for drawing an ellipse plot showing the kinematics of a 2-body reaction or decay. DALITZ RECTANGULAR calculates coordinates of points on the boundary of a rectangular Dalitz plot. DALITZ TRIANGULAR calculates coordinates of points on the boundary of a triangular Dalitz plot. There are short versions of CONFIDENCE (EVEN N and POISSON) that calculate confidence levels for the even-degree-of-freedom-chi/sup 2/ and the Poisson cases, and there is a short version of TWO BODY (CM) that calculates just the c.m. energy and initial-state momentum. The programs are written for the HP-97 calculator. (WHK)

  13. Adaptive neural control of MIMO nonlinear systems with a block-triangular pure-feedback control structure.

    Science.gov (United States)

    Chen, Zhenfeng; Ge, Shuzhi Sam; Zhang, Yun; Li, Yanan

    2014-11-01

    This paper presents adaptive neural tracking control for a class of uncertain multiinput-multioutput (MIMO) nonlinear systems in block-triangular form. All subsystems within these MIMO nonlinear systems are of completely nonaffine pure-feedback form and allowed to have different orders. To deal with the nonaffine appearance of the control variables, the mean value theorem is employed to transform the systems into a block-triangular strict-feedback form with control coefficients being couplings among various inputs and outputs. A systematic procedure is proposed for the design of a new singularity-free adaptive neural tracking control strategy. Such a design procedure can remove the couplings among subsystems and hence avoids the possible circular control construction problem. As a consequence, all the signals in the closed-loop system are guaranteed to be semiglobally uniformly ultimately bounded. Moreover, the outputs of the systems are ensured to converge to a small neighborhood of the desired trajectories. Simulation studies verify the theoretical findings revealed in this paper.

  14. The effect of a soap film on a catenary: measurement of surface tension from the triangular configuration

    Energy Technology Data Exchange (ETDEWEB)

    Behroozi, F [Department of Physics, University of Northern Iowa, Cedar Falls, IA 50614 (United States); Behroozi, P S, E-mail: behroozi@uni.edu [Department of Physics, Stanford University, Stanford, CA 94305 (United States)

    2011-09-15

    A chain assumes the well-known shape known as a catenary when it hangs loosely from two points in a gravitational field. The correct solution of the catenary was one of the early triumphs of the newly invented calculus of variations at the end of the 17th century. Here we revisit the catenary and show that, for a chain hanging from a horizontal rod, three new and distinct configurations are possible if a soap film covers the area bounded by the chain and the rod. We first review the general problem and discuss the conditions under which the chain assumes a concave, triangular or convex configuration. The deciding factor is the strength of surface tension relative to the gravitational force per unit length of the chain. The conditions under which the chain assumes the shape of a perfect triangle are discussed in greater detail and analysed to obtain the tension along the chain. The triangular configuration is especially intriguing to undergraduates and may be used as a simple experiment to obtain the surface tension of the soap solution by measuring just one angle of the triangle.

  15. Triangular flow of negative pions emitted in PbAu collisions at $\\sqrt{s_{NN}} $= 17.3~GeV

    CERN Document Server

    Adamová, D.

    Differential triangular flow, $v_3(p_T)$, of negative pions is measured at $\\sqrt{s_{NN}}$= 17.3~GeV around midrapidity by the CERES/NA45 experiment at CERN in central PbAu collisions in the range 0-30\\% with a mean centrality of 5.5\\%. This is the first measurement of the triangular flow at SPS energies. The $p_T$ range extends from about 0.05~GeV/c to more than 2~GeV/c. The triangular flow magnitude, corrected for the HBT effects, is smaller by a factor of about 2 than the one measured by the PHENIX experiment at RHIC and the ALICE experiment at the LHC. Within the analyzed range of central collisions no significant centrality dependence is observed. The data are found to be well described by a viscous hydro calculation combined with an UrQMD cascade model for the late stages.

  16. Flexible and transparent nanogenerators based on a composite of lead-free ZnSnO{sub 3} triangular-belts

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jyh Ming [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Department of Materials Science and Engineering, Feng Chia University, 100 Wenhwa Rd, Seatwen, Taichung, 40724 (China); Xu, Chen; Zhang, Yan; Yang, Ya; Zhou, Yusheng; Wang, Zhong Lin [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2012-11-27

    A flexible and transparent lead-free triangular-belt ZnSnO{sub 3} nanogenerator is demonstrated. When a mechanical deformation of {approx}0.1% is applied to the triangular-belt ZnSnO{sub 3} nanogenerator, the output voltage and current reached 5.3 V and 0.13 {mu}A, respectively, which indicated a maximum output power density of {approx}11 {mu}W.cm{sup -3}. This is the highest output power that has been demonstrated by lead-free ZnSnO{sub 3} triangular-belts. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. The high current transport experiment for heavy ion inertial fusion

    Energy Technology Data Exchange (ETDEWEB)

    Prost, L.R.; Baca, D.; Bieniosek, F.M.; Celata, C.M.; Faltens, A.; Henestroza, E.; Kwan, J.W.; Leitner, M.; Seidl, P.A.; Waldron, W.L.; Cohen, R.; Friedman, A.; Grote, D.; Lund, S.M.; Molvik, A.W.; Morse, E.

    2004-05-01

    The High Current Experiment (HCX) at Lawrence Berkeley National Laboratory is part of the US program to explore heavy-ion beam transport at a scale representative of the low-energy end of an induction linac driver for fusion energy production. The primary mission of this experiment is to investigate aperture fill factors acceptable for the transport of space-charge-dominated heavy-ion beams at high intensity (line charge density {approx} 0.2 {micro}C/m) over long pulse durations (4 {micro}s) in alternating gradient focusing lattices of electrostatic or magnetic quadrupoles. This experiment is testing transport issues resulting from nonlinear space-charge effects and collective modes, beam centroid alignment and steering, envelope matching, image charges and focusing field nonlinearities, halo and, electron and gas cloud effects. We present the results for a coasting 1 MeV K{sup +} ion beam transported through ten electrostatic quadrupoles. The measurements cover two different fill factor studies (60% and 80% of the clear aperture radius) for which the transverse phase-space of the beam was characterized in detail, along with beam energy measurements and the first halo measurements. Electrostatic quadrupole transport at high beam fill factor ({approx}80%) is achieved with acceptable emittance growth and beam loss, even though the initial beam distribution is not ideal (but the emittance is low) nor in thermal equilibrium. We achieved good envelope control, and rematching may only be needed every ten lattice periods (at 80% fill factor) in a longer lattice of similar design. We also show that understanding and controlling the time dependence of the envelope parameters is critical to achieving high fill factors, notably because of the injector and matching section dynamics.

  18. High current transport experiment for heavy ion inertial fusion

    Directory of Open Access Journals (Sweden)

    L. R. Prost

    2005-02-01

    Full Text Available The High Current Experiment at Lawrence Berkeley National Laboratory is part of the U.S. program to explore heavy-ion beam transport at a scale representative of the low-energy end of an induction linac driver for fusion energy production. The primary mission of this experiment is to investigate aperture fill factors acceptable for the transport of space-charge-dominated heavy-ion beams at high intensity (line charge density ∼0.2  μC/m over long pulse durations (4  μs in alternating gradient focusing lattices of electrostatic or magnetic quadrupoles. This experiment is testing transport issues resulting from nonlinear space-charge effects and collective modes, beam centroid alignment and steering, envelope matching, image charges and focusing field nonlinearities, halo, and electron and gas cloud effects. We present the results for a coasting 1 MeV K^{+} ion beam transported through ten electrostatic quadrupoles. The measurements cover two different fill factor studies (60% and 80% of the clear aperture radius for which the transverse phase space of the beam was characterized in detail, along with beam energy measurements and the first halo measurements. Electrostatic quadrupole transport at high beam fill factor (≈80% is achieved with acceptable emittance growth and beam loss, even though the initial beam distribution is not ideal (but the emittance is low nor in thermal equilibrium. We achieved good envelope control, and rematching may only be needed every ten lattice periods (at 80% fill factor in a longer lattice of similar design. We also show that understanding and controlling the time dependence of the envelope parameters is critical to achieving high fill factors, notably because of the injector and matching section dynamics.

  19. The magnetic properties of transition metals on triangular lattices and the crystallography of new and previously reported sulfates

    Science.gov (United States)

    West, D. Vincent

    The study of magnetism on a triangular lattice has intrigued physicists for some years, as this special arrangement allows the probing of new electronic phenomena by frustrating the dominant nearest-neighbor couplings. Every project presented here bears importance to geometric frustration. Three chapters present research on compounds in previously known crystal structure families that exhibit signs of geometric frustration: pyrochlores (ch. 2), anhydrous alums (ch. 3) and yavapaiites (ch. 4). The last two chapters (5 and 6) present the discovery of two previously unknown crystal structures, both possessing triangles within their structures, and which may lead to future discoveries within the field of geometric frustration. In addition to the magnetic properties of triangular lattice materials, each project presents important progress in the crystallography of these materials. It was shown that the pyrochlores could soak up oxygen into the normally vacant 8a site forming a metastable material with excess oxygen. The anhydrous alums were shown to exhibit an inherent disorder along one crystallographic axis. The discovery of this feature led to the reassignment of the crystal structure of anhydrous alum itself, KAl(SO4)2. A comparison of the known anhydrous alums and the related yavapaiite structures has shown a non-systematic correlation of cation radius and electron count to specific crystallographic features such as unit cell size and bond angles. The discovery of two crystal structures in the Pb-Mn-SO4 phase diagram revealed novel crystallographic features. The first, PbMn5(SO4) 6, has unique Mn2+2O9 dimers of face sharing octahedra and two complementary triangular layers of magnetic cations that resemble regular polygon tilings. The second material, PbMn(SO 4)2, forms a rare chiral structure in which the Pb and Mn atoms spiral around each other along one axis to form a double helix. Overall, the work provides insight into the interplay of magnetism, magnetic

  20. Absorption Spectrum and Density of States of Square, Rectangular, and Triangular Frenkel Exciton Systems with Gaussian Diagonal Disorder

    Directory of Open Access Journals (Sweden)

    Ibrahim Avgin

    2017-01-01

    Full Text Available Using the coherent potential approximation, we investigate the effects of disorder on the optical absorption and the density of states of Frenkel exciton systems on square, rectangular, and triangular lattices with nearest-neighbor interactions and a Gaussian distribution of transition energies. The analysis is based on an elliptic integral approach that gives results over the entire spectrum. The results for the square lattice are in good agreement with the finite-array calculations of Schreiber and Toyozawa. Our findings suggest that the coherent potential approximation can be useful in interpreting the optical properties of two-dimensional systems with dominant nearest-neighbor interactions and Gaussian diagonal disorder provided the optically active states are Frenkel excitons.

  1. An efficient optimization method to improve the measuring accuracy of oxygen saturation by using triangular wave optical signal

    Science.gov (United States)

    Li, Gang; Yu, Yue; Zhang, Cui; Lin, Ling

    2017-09-01

    The oxygen saturation is one of the important parameters to evaluate human health. This paper presents an efficient optimization method that can improve the accuracy of oxygen saturation measurement, which employs an optical frequency division triangular wave signal as the excitation signal to obtain dynamic spectrum and calculate oxygen saturation. In comparison to the traditional method measured RMSE (root mean square error) of SpO2 which is 0.1705, this proposed method significantly reduced the measured RMSE which is 0.0965. It is notable that the accuracy of oxygen saturation measurement has been improved significantly. The method can simplify the circuit and bring down the demand of elements. Furthermore, it has a great reference value on improving the signal to noise ratio of other physiological signals.

  2. Grey-Markov prediction model based on background value optimization and central-point triangular whitenization weight function

    Science.gov (United States)

    Ye, Jing; Dang, Yaoguo; Li, Bingjun

    2018-01-01

    Grey-Markov forecasting model is a combination of grey prediction model and Markov chain which show obvious optimization effects for data sequences with characteristics of non-stationary and volatility. However, the state division process in traditional Grey-Markov forecasting model is mostly based on subjective real numbers that immediately affects the accuracy of forecasting values. To seek the solution, this paper introduces the central-point triangular whitenization weight function in state division to calculate possibilities of research values in each state which reflect preference degrees in different states in an objective way. On the other hand, background value optimization is applied in the traditional grey model to generate better fitting data. By this means, the improved Grey-Markov forecasting model is built. Finally, taking the grain production in Henan Province as an example, it verifies this model's validity by comparing with GM(1,1) based on background value optimization and the traditional Grey-Markov forecasting model.

  3. Tight-binding electrons on triangular and kagome lattices under staggered modulated magnetic fields: quantum Hall effects and Hofstadter butterflies

    Energy Technology Data Exchange (ETDEWEB)

    Li Juan; Wang Yifei; Gong Changde, E-mail: yfwang_nju@hotmail.com [Center for Statistical and Theoretical Condensed Matter Physics, and Department of Physics, Zhejiang Normal University, Jinhua 321004 (China)

    2011-04-20

    We consider the tight-binding models of electrons on a two-dimensional triangular lattice and kagome lattice under staggered modulated magnetic fields. Such fields have two components: a uniform-flux part with strength {phi}, and a staggered-flux part with strength {Delta}{phi}. Various properties of the Hall conductances and Hofstadter butterflies are studied. When {phi} is fixed, variation of {Delta}{phi} leads to the quantum Hall transitions and Chern numbers of Landau subbands being redistributed between neighboring pairs. The energy spectra with nonzero {Delta}{phi}s have similar fractal structures but quite different energy gaps compared with the original Hofstadter butterflies of {Delta}{phi} = 0. Moreover, the fan-like structure of Landau levels in the low magnetic field region is also modified appreciably by {Delta}{phi}.

  4. Algebraic Bethe ansatz for the XXZ Heisenberg spin chain with triangular boundaries and the corresponding Gaudin model

    Directory of Open Access Journals (Sweden)

    N. Manojlović

    2017-10-01

    Full Text Available The implementation of the algebraic Bethe ansatz for the XXZ Heisenberg spin chain in the case, when both reflection matrices have the upper-triangular form is analyzed. The general form of the Bethe vectors is studied. In the particular form, Bethe vectors admit the recurrent procedure, with an appropriate modification, used previously in the case of the XXX Heisenberg chain. As expected, these Bethe vectors yield the strikingly simple expression for the off-shell action of the transfer matrix of the chain as well as the spectrum of the transfer matrix and the corresponding Bethe equations. As in the XXX case, the so-called quasi-classical limit gives the off-shell action of the generating function of the corresponding trigonometric Gaudin Hamiltonians with boundary terms.

  5. Brief report: Intimacy, passion, and commitment in romantic relationships--validation of a 'triangular love scale' for adolescents.

    Science.gov (United States)

    Overbeek, Geertjan; Ha, Thao; Scholte, Ron; de Kemp, Raymond; Engels, Rutger C M E

    2007-06-01

    This study examined the psychometric properties of an adolescent version of the 'triangular love scale' (TLS), which assesses three components of romantic relationships: intimacy, passion, and commitment. Using data from 435 Dutch adolescents aged 12-18 years, we found evidence for convergent validity, showing that dimensions of intimacy, passion, and commitment were all positively correlated with relationship satisfaction and duration. Evidence was also found for divergent validity, as adolescents' perceptions of the main (dis)advantages of being involved in romantic relationships showed a specific pattern of associations with intimacy, passion, and commitment. Finally, CFA analyses in LISREL showed that a model in which all separate questionnaire items were specified to load on three underlying, correlated factors (intimacy, passion, commitment) fit the data adequately. Overall, this measure seems appropriate for use with adolescents.

  6. A corotational flat triangular element for large strain analysis of thin shells with application to soft biological tissues

    Science.gov (United States)

    Caselli, Federica; Bisegna, Paolo

    2014-09-01

    A flat triangular element for the nonlinear analysis of thin shells is presented. The formulation relies on (i) a polar decomposition based corotational framework and (ii) a core-element kinematic description adopting the multiplicative superposition of membrane and bending actions. The resulting element is a refined yet simple three-node displacement-based triangle accounting for thickness extensibility and initial shell curvature, and equipped with a fully consistent tangent stiffness. Numerical tests involving shell structures made of rubber-like materials or fibred biological tissues show the effectiveness of the proposed element and its suitability to problems characterized by large displacements, large rotations, large membrane strains and bending. A Matlab toolkit implementing the present formulation is provided as supplementary material.

  7. Assimilation of coastal acoustic tomography data using an unstructured triangular grid ocean model for water with complex coastlines and islands

    Science.gov (United States)

    Zhu, Ze-Nan; Zhu, Xiao-Hua; Guo, Xinyu; Fan, Xiaopeng; Zhang, Chuanzheng

    2017-09-01

    For the first time, we present the application of an unstructured triangular grid to the Finite-Volume Community Ocean Model using the ensemble Kalman filter scheme, to assimilate coastal acoustic tomography (CAT) data. The fine horizontal and vertical current field structures around the island inside the observation region were both reproduced well. The assimilated depth-averaged velocities had better agreement with the independent acoustic Doppler current profiler (ADCP) data than the velocities obtained by inversion and simulation. The root-mean-square difference (RMSD) between depth-averaged current velocities obtained by data assimilation and those obtained by ADCPs was 0.07 m s-1, which was less than the corresponding difference obtained by inversion and simulation (0.12 and 0.17 m s-1, respectively). The assimilated vertical layer velocities also exhibited better agreement with ADCP than the velocities obtained by simulation. RMSDs between assimilated and ADCP data in vertical layers ranged from 0.02 to 0.14 m s-1, while RMSDs between simulation and ADCP data ranged from 0.08 to 0.27 m s-1. These results indicate that assimilation had the highest accuracy. Sensitivity experiments involving the elimination of sound transmission lines showed that missing data had less impact on assimilation than on inversion. Sensitivity experiments involving the elimination of CAT stations showed that the assimilation with four CAT stations was the relatively economical and reasonable procedure in this experiment. These results indicate that, compared with inversion and simulation, data assimilation of CAT data with an unstructured triangular grid is more effective in reconstructing the current field.

  8. Clinical results of resection arthrodesis by triangular external fixation for posttraumatic arthrosis of the ankle joint in 89 cases

    Directory of Open Access Journals (Sweden)

    Kiene J

    2009-01-01

    Full Text Available Abstract The methods for ankle arthrodesis differ significantly, probably a sign that no method is clearly superior to others. In the last ten years there is a clear favour toward internal fixation. We retrospectively evaluate the technique and evaluate the clinical long term results of external fixation in a triangular frame. Patients and Methods From 1994 to 2001 a consecutive series of 95 patients with end stage arthritis of the ankle joint were treated. Retrospectively the case notes were evaluated regarding trauma history, medical complaints, further injuries and illnesses, walking and pain status and occupational issues and the clinical examination before arthrodesis. Mean age at the index procedure was 45.4 years (18-82, 67 patients were male (70.5%. Via a bilateral approach the malleoli and the joint surfaces were resected. An AO fixator was applied with two Steinmann-nails inserted with approximately 8 cm distance in the distal tibia, one in the neck of the talus and one in the dorsal calcaneus. The fixator was removed after approximately 12 weeks. Follow up examination at mean 4.4 years included a standardised questionnaire and a clinical examination including the criteria of the AOFAS-Score and radiographs. Results: Due to different complications, 8 (8.9% further surgical procedures were necessary including 1 below knee amputation. In 4 patients a non-union of the ankle arthrodesis developed (4.5%. The mean AOFAS score improved from 20.8 to 69.3 points. Conclusion Non-union rates and clinical results of arthrodesis by triangular external fixation of the ankle joint do not differ to internal fixation methods. The complication rate and the reduced patient comfort reserve this method mainly for infected arthritis and complicated soft tissue situations.

  9. Ground states, magnetization plateaus and bipartite entanglement of frustrated spin-1/2 Ising-Heisenberg and Heisenberg triangular tubes

    Energy Technology Data Exchange (ETDEWEB)

    Alécio, Raphael C.; Lyra, Marcelo L. [Instituto de Física, Universidade Federal de Alagoas, 57072–970 Maceió-AL (Brazil); Strečka, Jozef [Department of Theoretical Physics and Astrophysics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9, 040 01 Košice (Slovakia)

    2016-11-01

    The ground-state phase diagram, magnetization process and bipartite entanglement of the frustrated spin-1/2 Ising-Heisenberg and Heisenberg triangular tube (three-leg ladder) are investigated in a non-zero external magnetic field. The exact ground-state phase diagram of the spin-1/2 Ising-Heisenberg tube with Heisenberg intra-rung and Ising inter-rung couplings consists of six distinct gapped phases, which manifest themselves in a magnetization curve as intermediate plateaus at zero, one-third and two-thirds of the saturation magnetization. Four out of six available ground states exhibit quantum entanglement between two spins from the same triangular unit evidenced by a non-zero concurrence. Density-matrix renormalization group calculations are used in order to construct the ground-state phase diagram of the analogous but purely quantum spin-1/2 Heisenberg tube with Heisenberg intra- and inter-rung couplings, which consists of four gapped and three gapless phases. The Heisenberg tube shows a continuous change of the magnetization instead of a plateau at zero magnetization, while the intermediate one-third and two-thirds plateaus may be present or not in the zero-temperature magnetization curve. - Highlights: • Ground-state properties of Ising-Heisenberg and full Heisenberg spin tubes are studied. • Phases with 1/3 and 2/3 magnetization plateaus are present in both models. • We unveil the region in the parameter space on which inter-rung quantum fluctuations are relevant. • The full Heisenberg tube exhibits quantum bipartite entanglement between intra- as well as inter-rung spins.

  10. Triangular CdS nanostructure: effect of Mn doping on photoluminescence, electron spin resonance, and magneto-optical properties

    Science.gov (United States)

    Jadhav, Punam A.; Panmand, Rajendra P.; Patil, Deepak R.; Fouad, H.; Gosavi, Suresh W.; Kale, Bharat B.

    2017-06-01

    In this paper, we report synthesis and study of magneto-optic Faraday effect for dilute magnetic semiconductor nanostructure. The colloidal CdS nanocrystals were prepared via hot injection method and successfully doped with Mn2+ cations. The synthesized nanoparticles were characterized by using UV-Vis spectroscopy, X-ray diffraction, photoluminescence spectroscopy, transmission electron microscopy, and electron spin resonance spectroscopy. Systematic studies on effect of Mn2+ doping on photoluminescence, electron spin resonance, and magneto-optical properties are carried out. UV-Vis spectral analysis confirms blue shift in bandgap of CdS nanoparticles due to quantum confinement effect. The X-ray diffraction study confirms hexagonal wurtzite phase formation of CdS nanoparticles without any impurity phases. TEM analysis confirms uniform particle size, having particle size distribution around 5 nm. As-synthesized undoped CdS shows triangular-shaped nanocrystals with hexagonal structure; however, triangular shape of CdS nanoparticles is not conserved after Mn2+ doping. The photoluminescence characteristic spectra of Mn2+-doped CdS nanocrystals showed emission band at 660 nm and its intensity was found to increase with increasing Mn2+ concentration. Electron spin resonance signal, with six-line hyperfine structure splitting, confirmed doping of Mn2+ ions in CdS lattice. Magneto-optic measurements showed linear variation of Faraday rotation with respect to applied magnetic field, indicating paramagnetic behavior of Mn-doped CdS. The highest Verdet constant 24.81 deg/T cm was observed for 2% Mn-doped CdS nanocrystals, which further decreases with increasing Mn2+ concentration.

  11. An Investigation of the Dose Distribution from LDR Ir-192 Wires in the Triangular Implants of the Paris System using Polymer Gel Dosimetry

    Directory of Open Access Journals (Sweden)

    Azizollah Rahimi

    2010-12-01

    Full Text Available Introduction: Polymer gels are modern dosimeters providing three dimensional dose distributions. These dosimeters can be used in brachytherapy in which the tumor dimension is relatively small and the dose gradient is high. In this study, the ability of the MAGICA polymer gel was investigated for assessing the absolute dose values as well as the dose distribution of low dose rate (LDR Ir-192 wires in interstitial brachytherapy based in triangular implants of the Paris system. Material and Methods: A suitable phantom was made from Perspex. Glass tubes were used as the external tubes for holding the Ir-192 wires in the phantom. The MAGICA polymer gel was made and placed in the phantom. The phantom and the calibration tubes were irradiated using LDR Ir-192 wires and a Co-60 teletherapy unit respectively. They were subsequently imaged using an MRI scanner. The R2 (=1/T2 maps were extracted from several sequential T2-weighted MRI images. The dose values resulting from the polymer gel measurements at the reference points were compared with those from the common calculation method at the same points. In addition, the isodose curves resulting from gel dosimetry were compared with those from a brachytherapy treatment planning system (Flexiplan. Results: The average of the dose values measured with the gel at the reference points was 62.75% higher than those calculated at the same points. Investigating the isodose curves revealed that the maximum distance to agreement (DTAmax between the isodoses resulting from the gel and those obtained from the treatment planning system was less than 3 mm at different dose levels. Discussion and Conclusion: Although the MAGICA gel indicates a higher absolute dose value than those calculated commonly, it can give the relative dose values accurately. Therefore, it can be recommended to be used for the assessment of dose distributions for the treatment of tissues as well as quality control of the treatment planning systems.

  12. Internacionalização de empresas como política de desenvolvimento: uma abordagem de diplomacia triangular Company internationalization as a development policy: a triangular diplomacy approach

    Directory of Open Access Journals (Sweden)

    Ana Lucia Guedes

    2006-06-01

    Full Text Available Este artigo desenvolve uma abordagem analítica da inserção do Brasil no contexto internacional contemporâneo, com base na literatura de economia política internacional e de negócios internacionais, que transcende as tradicionais avaliações de política internacional por contemplar relações que envolvem atores estatais e nãoestatais. Assim, o artigo sustenta que os desafios a serem enfrentados pelo Brasil resultam da complexidade do sistema internacional contemporâneo. O artigo apresenta um debate crítico acerca da globalização com objetivo de desmistificar esse fenômeno e resgatar a possibilidade de governança pelo âmbito público. Para ilustrar esse debate, é apresentada uma breve análise sobre os impactos da globalização econômica, por meio de investimentos diretos externos, no Brasil. A abordagem analítica resultante enfatiza, com base no modelo de diplomacia triangular, que além das tradicionais negociações entre Estados, o Brasil precisa negociar com empresas estrangeiras e domésticas e, estas necessitam de alianças corporativas para enfrentar os desafios da economia mundial. Ao final, o artigo sugere que o governo brasileiro adote a internacionalização de empresas brasileiras como estratégia de desenvolvimento.This article develops an analytical approach of the insertion of Brazil in the international context, grounded on the international political economy and international business literature, going beyond the traditional analysis in international politics as it contemplates the relationships between state and non-state actors. As such, the article stresses that the challenges faced by Brazil result from the complexity of the current international system. The article presents a critical debate regarding the globalization so as to demystify this phenomenon and stress the possibility of public governance. In order to ilustrate this debate, it develops a short analysis of the impacts of economic globalization

  13. A triangular fuzzy TOPSIS-based approach for the application of water technologies in different emergency water supply scenarios.

    Science.gov (United States)

    Qu, Jianhua; Meng, Xianlin; Yu, Huan; You, Hong

    2016-09-01

    Because of the increasing frequency and intensity of unexpected natural disasters, providing safe drinking water for the affected population following a disaster has become a global challenge of growing concern. An onsite water supply technology that is portable, mobile, or modular is a more suitable and sustainable solution for the victims than transporting bottled water. In recent years, various water techniques, such as membrane-assisted technologies, have been proposed and successfully implemented in many places. Given the diversity of techniques available, the current challenge is how to scientifically identify the optimum options for different disaster scenarios. Hence, a fuzzy triangular-based multi-criteria, group decision-making tool was developed in this research. The approach was then applied to the selection of the most appropriate water technologies corresponding to the different emergency water supply scenarios. The results show this tool capable of facilitating scientific analysis in the evaluation and selection of emergency water technologies for enduring security drinking water supply in disaster relief.

  14. A Signal Based Triangular Structuring Element for Mathematical Morphological Analysis and Its Application in Rolling Element Bearing Fault Diagnosis

    Directory of Open Access Journals (Sweden)

    Zhaowen Chen

    2014-01-01

    Full Text Available Mathematical morphology (MM is an efficient nonlinear signal processing tool. It can be adopted to extract fault information from bearing signal according to a structuring element (SE. Since the bearing signal features differ for every unique cause of failure, the SEs should be well tailored to extract the fault feature from a particular signal. In the following, a signal based triangular SE according to the statistics of the magnitude of a vibration signal is proposed, together with associated methodology, which processes the bearing signal by MM analysis based on proposed SE to get the morphology spectrum of a signal. A correlation analysis on morphology spectrum is then employed to obtain the final classification of bearing faults. The classification performance of the proposed method is evaluated by a set of bearing vibration signals with inner race, ball, and outer race faults, respectively. Results show that all faults can be detected clearly and correctly. Compared with a commonly used flat SE, the correlation analysis on morphology spectrum with proposed SE gives better performance at fault diagnosis of bearing, especially the identification of the location of outer race fault and the level of fault severity.

  15. Analytical and numerical construction of vertical periodic orbits about triangular libration points based on polynomial expansion relations among directions

    Science.gov (United States)

    Qian, Ying-Jing; Yang, Xiao-Dong; Zhai, Guan-Qiao; Zhang, Wei

    2017-08-01

    Innovated by the nonlinear modes concept in the vibrational dynamics, the vertical periodic orbits around the triangular libration points are revisited for the Circular Restricted Three-body Problem. The ζ -component motion is treated as the dominant motion and the ξ and η -component motions are treated as the slave motions. The slave motions are in nature related to the dominant motion through the approximate nonlinear polynomial expansions with respect to the ζ -position and ζ -velocity during the one of the periodic orbital motions. By employing the relations among the three directions, the three-dimensional system can be transferred into one-dimensional problem. Then the approximate three-dimensional vertical periodic solution can be analytically obtained by solving the dominant motion only on ζ -direction. To demonstrate the effectiveness of the proposed method, an accuracy study was carried out to validate the polynomial expansion (PE) method. As one of the applications, the invariant nonlinear relations in polynomial expansion form are used as constraints to obtain numerical solutions by differential correction. The nonlinear relations among the directions provide an alternative point of view to explore the overall dynamics of periodic orbits around libration points with general rules.

  16. Thermal Entanglement in XXZ Heisenberg Model for Coupled Spin-Half and Spin-One Triangular Cell

    Science.gov (United States)

    Najarbashi, Ghader; Balazadeh, Leila; Tavana, Ali

    2018-01-01

    In this paper, we investigate the thermal entanglement of two-spin subsystems in an ensemble of coupled spin-half and spin-one triangular cells, (1/2, 1/2, 1/2), (1/2, 1, 1/2), (1, 1/2, 1) and (1, 1, 1) with the XXZ anisotropic Heisenberg model subjected to an external homogeneous magnetic field. We adopt the generalized concurrence as the measure of entanglement which is a good indicator of the thermal entanglement and the critical points in the mixed higher dimensional spin systems. We observe that in the near vicinity of the absolute zero, the concurrence measure is symmetric with respect to zero magnetic field and changes abruptly from a non-null to null value for a critical magnetic field that can be signature of a quantum phase transition at finite temperature. The analysis of concurrence versus temperature shows that there exists a critical temperature, that depends on the type of the interaction, i.e. ferromagnetic or antiferromagnetic, the anisotropy parameter and the strength of the magnetic field. Results show that the pairwise thermal entanglement depends on the third spin which affects the maximum value of the concurrence at absolute zero and at quantum critical points.

  17. An Extreme Learning Machine Based on the Mixed Kernel Function of Triangular Kernel and Generalized Hermite Dirichlet Kernel

    Directory of Open Access Journals (Sweden)

    Senyue Zhang

    2016-01-01

    Full Text Available According to the characteristics that the kernel function of extreme learning machine (ELM and its performance have a strong correlation, a novel extreme learning machine based on a generalized triangle Hermitian kernel function was proposed in this paper. First, the generalized triangle Hermitian kernel function was constructed by using the product of triangular kernel and generalized Hermite Dirichlet kernel, and the proposed kernel function was proved as a valid kernel function of extreme learning machine. Then, the learning methodology of the extreme learning machine based on the proposed kernel function was presented. The biggest advantage of the proposed kernel is its kernel parameter values only chosen in the natural numbers, which thus can greatly shorten the computational time of parameter optimization and retain more of its sample data structure information. Experiments were performed on a number of binary classification, multiclassification, and regression datasets from the UCI benchmark repository. The experiment results demonstrated that the robustness and generalization performance of the proposed method are outperformed compared to other extreme learning machines with different kernels. Furthermore, the learning speed of proposed method is faster than support vector machine (SVM methods.

  18. InP-based pseudomorphic InAs/InGaAs triangular quantum well lasers with bismuth surfactant.

    Science.gov (United States)

    Ji, W Y; Gu, Y; Zhang, Y G; Ma, Y J; Chen, X Y; Gong, Q; Du, B; Shi, Y H

    2017-11-01

    An InP-based 2.1 μm InAs/In 0.53 Ga 0.47 As triangular quantum well laser grown with Bi surfactant has shown improved performance in comparison to the device with the same structure but grown without Bi surfactant. Under continuous-wave driving operation, the output light power is increased from 32.6 to 37.5 mW at the same injecting current of 850 mA at 200 K. The external differential and internal quantum efficiencies for the laser with Bi surfactant are 18.4% and 41%, respectively, which are correspondingly higher than 13.1% and 31% for the reference device. Furthermore, a decreased internal loss from 20.9 to 17.6  cm -1 for the Bi surfactant laser is also observed. These results suggest that Bi surfactant is promising for further enhancing performances of strained quantum well laser diodes.

  19. Morphotectonic evolution of triangular facets and wine-glass valleys in the Noakoh anticline, Zagros, Iran: Implications for active tectonics

    Science.gov (United States)

    Bahrami, Shahram

    2012-07-01

    The Noakoh anticline is located in Kermanshah province and is part of the Simply Folded Belt of Zagros. Boundaries of 97 triangular facets and 67 wine-glass (W-G) valleys, which formed on anticline limbs, were delineated using Quickbird satellite imagery. The strata dip (D), area (A), base length (BL), topographic slope (S) of facets, the maximum width (M), outlet width (O) and ratio of maximum width to outlet width (W index) of W-G valleys were analysed in detail. Noakoh anticline was subdivided into 9 tectonic zones on the basis of dip, topographic slopes and width of limbs. Results show that there are strong positive correlations between means of D-BL and S-BL pairs. Poor positive correlations exist between means of D-A and S-A pairs. Among W-G valley metrics, the W index has strong relations with D and S parameters. Based on the results, steep facets with long bases and well developed W-G valleys with narrow outlets and wide upper parts are associated with more rotated limbs having steep slopes. Facets on the northeastern slope have more forest cover, micro-organism activity, karstic features and soil cover, whereas facets on relatively drier southwestern slope are characterized by physical weathering processes and minor karstic landforms. This study demonstrates that, apart from tectonic activity as a major control on the morphometry of facets and valleys, climate and slope aspect have also acted as secondary factors on the development of the studied landforms.

  20. Detection and characterization of symmetry-broken long-range orders in the spin-1/2 triangular Heisenberg model

    Science.gov (United States)

    Saadatmand, S. N.; McCulloch, I. P.

    2017-08-01

    We present new numerical tools to analyze symmetry-broken phases in the context of SU (2 ) -symmetric translation-invariant matrix product states (MPS) and density-matrix renormalization-group (DMRG) methods for infinite cylinders, and determine the phase diagram of the geometrically frustrated triangular Heisenberg model with nearest- and next-nearest-neighbor (NN and NNN) interactions. The appearance of Nambu-Goldstone modes in the excitation spectrum is characterized by "tower of states" levels in the momentum-resolved entanglement spectrum. Symmetry-breaking phase transitions are detected by a combination of the correlation lengths and second and fourth cumulants of the magnetic order parameters (which we call the Binder ratio), even though symmetry implies that the order parameter itself is strictly zero. Using this approach, we have identified a 120∘ order, a columnar order, and an algebraic spin liquid (specific to width-6 systems), alongside the previously studied topological spin liquid phase. For the latter, we also demonstrate robustness against chiral perturbations.

  1. Phase transitions and critical properties in the antiferromagnetic Ising model on a layered triangular lattice with allowance for intralayer next-nearest-neighbor interactions

    Energy Technology Data Exchange (ETDEWEB)

    Badiev, M. K., E-mail: m-zagir@mail.ru; Murtazaev, A. K.; Ramazanov, M. K. [Russian Academy of Sciences, Institute of Physics, Dagestan Scientific Center (Russian Federation)

    2016-10-15

    The phase transitions (PTs) and critical properties of the antiferromagnetic Ising model on a layered (stacked) triangular lattice have been studied by the Monte Carlo method using a replica algorithm with allowance for the next-nearest-neighbor interactions. The character of PTs is analyzed using the histogram technique and the method of Binder cumulants. It is established that the transition from the disordered to paramagnetic phase in the adopted model is a second-order PT. Static critical exponents of the heat capacity (α), susceptibility (γ), order parameter (β), and correlation radius (ν) and the Fischer exponent η are calculated using the finite-size scaling theory. It is shown that (i) the antiferromagnetic Ising model on a layered triangular lattice belongs to the XY universality class of critical behavior and (ii) allowance for the intralayer interactions of next-nearest neighbors in the adopted model leads to a change in the universality class of critical behavior.

  2. Synthesis of uniform gold nanoparticles using non-pathogenic bio-control agent: evolution of morphology from nano-spheres to triangular nanoprisms.

    Science.gov (United States)

    Mukherjee, P; Roy, Mainak; Mandal, B P; Choudhury, Sipra; Tewari, R; Tyagi, A K; Kale, S P

    2012-02-01

    Green synthesis of gold nanospheres with uniform diameter and triangular nanoprisms with optically flat surface was carried out using a non-pathogenic bio-control agent Trichoderma asperellum for reduction of HAuCl(4). Kinetics of the reaction was monitored by UV-Vis absorption spectroscopy. No additional capping/complexing agent was used for stabilizing the gold nanoparticles. Evolution of morphology from pseudospherical nanoparticles to triangular nanoprisms was studied by transmission electron microscopy (TEM). It revealed that three or more pseudospheres fused to form nanoprisms of different shapes and sizes. Slow rate of reduction of HAuCl(4) by constituents of cell-free fungal extract was instrumental in producing such exotic morphologies. Isolation of gold nanotriangles from the reacting masses was achieved by differential centrifugation. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Triangular prism-shaped β-peptoid helices as unique biomimetic scaffolds

    DEFF Research Database (Denmark)

    Laursen, Jonas Striegler; Harris, Pernille; Fristrup, Peter

    2015-01-01

    β-Peptoids are peptidomimetics based on N-alkylated β-aminopropionic acid residues (or N-alkyl-β-alanines). This type of peptide mimic has previously been incorporated in biologically active ligands and has been hypothesized to be able to exhibit foldamer properties. Here we show, for the first t...... of novel biomimetics that display functional groups with high accuracy in three dimensions, which has potential for development of new functional materials....

  4. High power, high efficiency continuous-wave 808 nm laser diode arrays

    Science.gov (United States)

    Wang, Zhenfu; Li, Te; Yang, Guowen; Song, Yunfei

    2017-12-01

    The continuous-wave 100 W-class 808 nm laser diode arrays with extremely high power conversion efficiency of 68% were reported at the heatsink temperature of 25 °C. To the best of our knowledge, this was the highest power conversion efficiency at continuous-wave 106 W 808 nm laser diode array with 50% fill factor so far. An asymmetric broad waveguide epitaxial structure with very low internal optical loss of 0.5 cm-1 was presented. In order to improve the efficiency, various fill factor devices were studied. The 50 W laser diode array with 30% fill factoir and 1.0 mm cavity length demonstrated power conversion efficiency of 71% at heatsink temperature of 15 °C.

  5. Extension of the analytic nodal diffusion solver ANDES to triangular-Z geometry and coupling with COBRA-IIIc for hexagonal core analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lozano, Juan-Andres, E-mail: lozano@din.upm.e [Departamento de Ingenieria Nuclear, Universidad Politecnica de Madrid (UPM), Jose G. Abascal, 2, 28006 Madrid (Spain); Jimenez, Javier; Garcia-Herranz, Nuria; Aragones, Jose-Maria [Departamento de Ingenieria Nuclear, Universidad Politecnica de Madrid (UPM), Jose G. Abascal, 2, 28006 Madrid (Spain)

    2010-03-15

    In this paper the extension of the multigroup nodal diffusion code ANDES, based on the Analytic Coarse Mesh Finite Difference (ACMFD) method, from Cartesian to hexagonal geometry is presented, as well as its coupling with the thermal-hydraulic (TH) code COBRA-IIIc for hexagonal core analysis. In extending the ACMFD method to hexagonal assemblies, triangular-Z nodes are used. In the radial plane, a direct transverse integration procedure is applied along the three directions that are orthogonal to the triangle interfaces. The triangular nodalization avoids the singularities, that appear when applying transverse integration to hexagonal nodes, and allows the advantage of the mesh subdivision capabilities implicit within that geometry. As for the thermal-hydraulics, the extension of the coupling scheme to hexagonal geometry has been performed with the capability to model the core using either assembly-wise channels (hexagonal mesh) or a higher refinement with six channels per fuel assembly (triangular mesh). Achieving this level of TH mesh refinement with COBRA-IIIc code provides a better estimation of the in-core 3D flow distribution, improving the TH core modelling. The neutronics and thermal-hydraulics coupled code, ANDES/COBRA-IIIc, previously verified in Cartesian geometry core analysis, can also be applied now to full three-dimensional VVER core problems, as well as to other thermal and fast hexagonal core designs. Verification results are provided, corresponding to the different cases of the OECD/NEA-NSC VVER-1000 Coolant Transient Benchmarks.

  6. Deriving rock transport properties from NMR relaxation experiments on partially de-saturated rocks using an inverse modelling approach based on the triangular pore model

    Science.gov (United States)

    Nordlund, C. L.; Mohnke, O.; Klitzsch, N.

    2013-12-01

    Nuclear magnetic resonance (NMR) is a method used over a wide field of geophysical applications e.g. petrophysics, logging or hydrogeology, to non-destructively and quickly determine transport and storage properties of rocks and soils. Measured NMR amplitudes indicate the rock's fluid content, whereas the NMR relaxation rates are used to derive pore size distributions and permeability as they are related to physiochemical properties of the rock-fluid interface, i.e. surface relaxivity. The aim of this work is to utilize triangular pore shapes in the inverse modeling of NMR relaxation data in order to better predict the water retention curves. Therefore, an inverse modeling scheme (Mohnke et al.; this conference) to derive NMR surface relaxivity along with pore radii distributions are determined has been adapted on the basis of triangular pore bundle models. . This approach then offers the advantage of having the triangular pores be partially saturated, thus accounting for a residual water content trapped in pore corners during drainage and imbibition (Tuller and Or, 2001). Additionally, besides the trapped water the presence of a water film at the pore walls is accounted for in the modeled and inverted NMR relaxation time distributions and thus allows to more accurately describe laboratory measurement results. Numerical parameter studies were carried out to assess the influence of pore shapes and contact angles on both, transport and NMR properties. Inverse models derived from laboratory NMR data on partially saturated reservoir rocks are in a good agreement with measured water retention data.

  7. Triangular flow of negative pions emitted in PbAu collisions at √{sNN} = 17.3 GeV

    Science.gov (United States)

    Adamová, D.; Agakichiev, G.; Andronic, A.; Antończyk, D.; Appelshäuser, H.; Belaga, V.; Bielčíková, J.; Braun-Munzinger, P.; Busch, O.; Cherlin, A.; Damjanović, S.; Dietel, T.; Dietrich, L.; Drees, A.; Dubitzky, W.; Esumi, S. I.; Filimonov, K.; Fomenko, K.; Fraenkel, Z.; Garabatos, C.; Glässel, P.; Hering, G.; Holeczek, J.; Kalisky, M.; Karpenko, Iu.; Krobath, G.; Kushpil, V.; Maas, A.; Marín, A.; Milošević, J.; Miśkowiec, D.; Panebrattsev, Y.; Petchenova, O.; Petráček, V.; Radomski, S.; Rak, J.; Ravinovich, I.; Rehak, P.; Sako, H.; Schmitz, W.; Schuchmann, S.; Sedykh, S.; Shimansky, S.; Stachel, J.; Šumbera, M.; Tilsner, H.; Tserruya, I.; Tsiledakis, G.; Wessels, J. P.; Wienold, T.; Wurm, J. P.; Yurevich, S.; Yurevich, V.

    2017-01-01

    Differential triangular flow, v3 (pT), of negative pions is measured at √{sNN} = 17.3 GeV around midrapidity by the CERES/NA45 experiment at CERN in central PbAu collisions in the range 0-30% with a mean centrality of 5.5%. This is the first measurement as a function of transverse momentum of the triangular flow at SPS energies. The pT range extends from about 0.05 GeV/c to more than 2 GeV/c. The triangular flow magnitude, corrected for the HBT effects, is smaller by a factor of about 2 than the one measured by the PHENIX experiment at RHIC and the ALICE experiment at the LHC. Within the analyzed range of central collisions no significant centrality dependence is observed. The data are found to be well described by a viscous hydrodynamic calculation combined with an UrQMD cascade model for the late stages.

  8. Large-Scale Synthesis of Few-Layer F-BN Nanocages with Zigzag-Edge Triangular Antidot Defects and Investigation of the Advanced Ferromagnetism.

    Science.gov (United States)

    Si, Haibin; Lian, Gang; Wang, Aizhu; Cui, Deliang; Zhao, Mingwen; Wang, Qilong; Wong, Ching-Ping

    2015-12-09

    Investigation of light-element magnetism system is essential in fundamental and practical fields. Here, few-layer (∼3 nm) fluorinated hexagonal boron nitride (F-BN) nanocages with zigzag-edge triangular antidot defects were synthesized via a facile one-step solid-state reaction. They are free of metallic impurities confirmed by X-ray photoelectron spectroscopy, electron energy loss spectroscopy, and inductively coupled plasma atomic emission spectroscopy. Ferromagnetism is obviously observed in the BN nanocages. Saturation magnetization values of them differed by less than 7% between 5 and 300 K, indicating that the Curie temperature (Tc) was much higher than 300 K. By adjusting the concentration of triangular antidot defects and fluorine dopants, the ferromagnetic performance of BN nanocages could be effectively varied, indicating that the observed magnetism originates from triangular antidot defects and fluorination. The corresponding theoretical calculation shows that antidot defects and fluorine doping in BN lattice both favor spontaneous spin polarization and the formation of local magnetic moment, which should be responsible for long-range magnetic ordering in the sp material.

  9. Piezoelectric effect in chemical vapour deposition-grown atomic-monolayer triangular molybdenum disulfide piezotronics

    KAUST Repository

    Qi, Junjie

    2015-06-25

    High-performance piezoelectricity in monolayer semiconducting transition metal dichalcogenides is highly desirable for the development of nanosensors, piezotronics and photo-piezotransistors. Here we report the experimental study of the theoretically predicted piezoelectric effect in triangle monolayer MoS2 devices under isotropic mechanical deformation. The experimental observation indicates that the conductivity of MoS2 devices can be actively modulated by the piezoelectric charge polarization-induced built-in electric field under strain variation. These polarization charges alter the Schottky barrier height on both contacts, resulting in a barrier height increase with increasing compressive strain and decrease with increasing tensile strain. The underlying mechanism of strain-induced in-plane charge polarization is proposed and discussed using energy band diagrams. In addition, a new type of MoS2 strain/force sensor built using a monolayer MoS2 triangle is also demonstrated. Our results provide evidence for strain-gating monolayer MoS2 piezotronics, a promising avenue for achieving augmented functionalities in next-generation electronic and mechanical–electronic nanodevices.

  10. Triangular relationship among risky sexual behavior, addiction, and aggression: A systematic review.

    Science.gov (United States)

    Ahmadi, Khodabakhsh; Javadinia, Seyed Alireza; Saadat, Seyed Hassan; Ramezani, Mohammad Arash; Sedghijalal, Homa

    2017-08-01

    Risky sexual behavior (RSB), addiction, and aggression are three important personal and social factors which influence each other. To overview the potential relationship among RSB, addiction, and aggression to conduct an interactive model for the pathology and management of human behavior. This review article was carried out by searching studies in PubMed, Medline, Web of Science, Ebsco, IEEE, Scopus, Springer, MagIran, and IranMedex databases from the year 1993 to 2013. The search terms were violence, aggression, drug abuse, substance abuse, illicit drug, psychoactive drug, intravenous drug users, addiction and high-risk sexual relationships, unprotected sex, high risk sexual behavior, and sexual risk-taking. In this study, forty-nine studies were accepted for further screening, and met all our inclusion criteria (in English or Persian, full text, and included the search terms). Forty-nine articles were included; 17 out of 26 studies showed a significant correlation between addiction and risky sexual behavior, 15 out of 19 articles indicated a statistically significant correlation between aggression and addiction, and 9 out of 10 articles reported significant correlation between aggression and risky sexual behavior. According to the results, the triangle hypothesis of sex, addiction, and aggression led to the definition of the relationship among the variables of the hypothetical triangle based on the reviewed studies; and the proposed dual and triple relationship based on the conducted literature review was confirmed. This is not a meta-analysis, and there is no analysis of publication bias.

  11. In situ oxidation and reduction of triangular nickel nanoplates via environmental transmission electron microscopy

    KAUST Repository

    LAGROW, A.P.

    2017-08-29

    Understanding the oxidation and reduction mechanisms of transition metals, such as nickel (Ni), is important for their use in industrial applications of catalysis. A powerful technique for investigating the redox reactive species is in situ environmental transmission electron microscopy (ETEM), where oxidation and reduction can be tracked in real time. One particular difficulty in understanding the underlying reactions is understanding the underlying morphology of the starting structure in a reaction, in particular the defects contained in the material, and the exposed surface facets. Here-in, we use a colloidal nanoparticle synthesis in a continuous flow reactor to form nanoplates of nickel coated with oleylamine as a capping agent. We utilise an in situ heating procedure at 300 °C in vacuum to remove the oleylamine ligands, and then oxidise the Ni nanoparticles at 25 °C with 2 Pa oxygen, and follow the nanoparticles initial oxidation. After that, the nanoparticles are oxidised at 200 and 300 °C, making the size of the oxide shell increase to ∼4 nm. The oxide shell could be reduced under 2 Pa hydrogen at 500 °C to its initial size of ∼1 nm. High temperature oxidation encouraged the nanoparticles to form pure NiO nanoparticles, which occurred via the Kirkendall effect leading to hollowing and void formation.

  12. Literariness and Racial Consciousness in Paule Marshall’s Memoir Triangular Road and Gloria Naylor’s Fictionalized Memoir 1996

    Directory of Open Access Journals (Sweden)

    Łobodziec Agnieszka

    2015-12-01

    Full Text Available Black American women writers were side-lined by the literary canon as recently as the 1980s. Today, as a result of their agency, a distinct literary tradition that bears witness to black women’s particular expressiveness is recognized. Bernard Bell observes that the defining features common to most literary works by black American women are a focus on racist oppression, black female protagonists, the pursuit of demarginalization, women’s bonding, women’s relationship with the community, the power of emotions, and black female language. Although these elements refer predominantly to novels, they are also present in Paule Marshall’s memoir Triangular Road (2009 and Gloria Naylor’s fictionalized memoir 1996 (2005. Moreover, the two works are fitting examples of racial art, the point of departure of which, according to Black Arts Movement advocates, should be the black experience. Actually, since through memoirs the authors offer significant insights into themselves, the genre seems closer to this objective of racial art than novels. At the same time, taking into consideration the intricate plot structures, vivid images, and emotional intensity, their memoirs evidence the quality of literariness i.e., in formalist terms, the set of features that distinguish texts from non-literary ones, for instance, reports, articles, text books, and encyclopaedic biographical entries. Moreover, Marshall and Naylor utilize creative imagination incorporating fabulation, stories within stories, and people or events they have never personally encountered, which dramatizes and intensifies the experiences they relate. In Marshall’s memoir, the fictitious elements are discernable when she imagines the historical past. Naylor demarks imagined narrative passages with separate sections that intertwine with those based upon her actual life experience.

  13. High speed global shutter image sensors for professional applications

    Science.gov (United States)

    Wu, Xu; Meynants, Guy

    2015-04-01

    Global shutter imagers expand the use to miscellaneous applications, such as machine vision, 3D imaging, medical imaging, space etc. to eliminate motion artifacts in rolling shutter imagers. A low noise global shutter pixel requires more than one non-light sensitive memory to reduce the read noise. But larger memory area reduces the fill-factor of the pixels. Modern micro-lenses technology can compensate this fill-factor loss. Backside illumination (BSI) is another popular technique to improve the pixel fill-factor. But some pixel architecture may not reach sufficient shutter efficiency with backside illumination. Non-light sensitive memory elements make the fabrication with BSI possible. Machine vision like fast inspection system, medical imaging like 3D medical or scientific applications always ask for high frame rate global shutter image sensors. Thanks to the CMOS technology, fast Analog-to-digital converters (ADCs) can be integrated on chip. Dual correlated double sampling (CDS) on chip ADC with high interface digital data rate reduces the read noise and makes more on-chip operation control. As a result, a global shutter imager with digital interface is a very popular solution for applications with high performance and high frame rate requirements. In this paper we will review the global shutter architectures developed in CMOSIS, discuss their optimization process and compare their performances after fabrication.

  14. Triangularization of a Matrix

    Indian Academy of Sciences (India)

    desired equality are seen to be equal to tr(AA* BB*). This proves the theorem. The reader might try to find another proof of this the- orem. (If the reader is unable to find such a proof from the mere definition of normality, she should 'not be sur- prised. The statement is false in infinite-dimensional. Hilbert spaces. It is, however ...

  15. Triangularization of a Matrix

    Indian Academy of Sciences (India)

    Rajendra Bhatia1 Radha Mohan2. Indian Statistical Institute, New Delhi 110 016, India. Centre for Mathematical Sciences, St. Stephen's College, Delhi 110 007, India. Resonance – Journal of Science Education. Current Issue : Vol. 22, Issue 9 · Current Issue Volume 22 | Issue 9. September 2017. Home · Volumes & Issues ...

  16. Permanent magnet design for high-speed superconducting bearings

    Science.gov (United States)

    Hull, John R.; Uherka, Kenneth L.; Abdoud, Robert G.

    1996-01-01

    A high temperature superconducting bearing including a permanent magnet rotor levitated by a high temperature superconducting structure. The rotor preferably includes one or more concentric permanent magnet rings coupled to permanent magnet ring structures having substantially triangular and quadrangular cross-sections. Both alternating and single direction polarity magnet structures can be used in the bearing.

  17. Technical aspects of mitral valve repair in Barlow's valve with prolapse of both leaflets: triangular resection for excess tissue, sophisticated chordal replacement, and their combination (the restoration technique).

    Science.gov (United States)

    Miura, Takashi; Ariyoshi, Tsuneo; Tanigawa, Kazuyoshi; Matsukuma, Seiji; Yokose, Shougo; Sumi, Mizuki; Hisatomi, Kazuki; Tsuneto, Akira; Hashizume, Koji; Eishi, Kiyoyuki

    2015-02-01

    Histological degeneration in Barlow's valve mainly starts in the rough zone, frequently expands toward the chordae, and advances to the clear zone, resulting in a saccular aneurysm-like morphology in the prolapsed region. On this basis, we have repaired the prolapsed segment by triangular resection, chordal replacement and the combination (the restoration technique). The aim of this study was to report our initial findings and evaluate the efficacy of our technique. Twelve patients diagnosed with Barlow's valve with prolapse of both leaflets (5 women; mean age, 49 years) underwent the restoration technique between January 2008 and March 2013. We retrospectively reviewed short-term clinical outcomes. The mean duration of the clinical follow-up was 2.5 ± 1.7 years. The restoration technique was successfully performed in all patients. Predominant repair techniques were isolated triangular resection (anterior 8, posterior 9), a combination of triangular resection with chordal replacement (anterior 1, posterior 1), and isolated chordal replacement (anterior 3, posterior 1). All patients underwent complete mitral annuloplasty, and the mean ring size was 31 ± 2 mm. In-hospital mortality was not noted. Late transthoracic echocardiography showed no or trace mitral regurgitation without significant systolic anterior motion in all patients. The New York Heart Association functional class was significantly improved from 1.3 ± 0.5 before surgery to 1.0 ± 0.0 after it (p < 0.01). There were no late thromboembolic or bleeding events. Initial experience with the restoration technique has provided excellent results without significant systolic anterior motion. Our technique may contribute to improve late results in Barlow's valve.

  18. Magnetization Process of the Spin-1/2 Triangular-Lattice Heisenberg Antiferromagnet with Next-Nearest-Neighbor Interactions — Plateau or Nonplateau —

    Science.gov (United States)

    Nakano, Hiroki; Sakai, Tôru

    2017-11-01

    An S = 1/2 triangular-lattice Heisenberg antiferromagnet with next-nearest-neighbor (NNN) interactions is investigated under a magnetic field by the numerical-diagonalization method. It is known that, in both cases of weak and strong NNN interactions, this system reveals a magnetization plateau at one-third of the saturated magnetization. We examine the stability of this magnetization plateau when the amplitude of NNN interactions is varied. We find that a nonplateau region appears between the plateau phases in the cases of weak and strong NNN interactions.

  19. Spinon Fermi surface U (1 ) spin liquid in the spin-orbit-coupled triangular-lattice Mott insulator YbMgGaO4

    Science.gov (United States)

    Li, Yao-Dong; Lu, Yuan-Ming; Chen, Gang

    2017-08-01

    Motivated by the recent progress in the spin-orbit-coupled triangular lattice spin liquid candidate YbMgGaO4, we carry out a systematic projective symmetry group analysis and mean-field study of candidate U (1 ) spin-liquid ground states. Due to the spin-orbital entanglement of the Yb moments, the space-group symmetry operation transforms both the position and the orientation of the local moments, and hence it brings different features for the projective realization of the lattice symmetries from the cases with spin-only moments. Among the eight U (1 ) spin liquids that we find with the fermionic parton construction, only one spin-liquid state, which was proposed and analyzed by Yao Shen et al. [Nature (London) 540, 559 (2016), 10.1038/nature20614] and labeled as U1A00 in the present work, stands out and gives a large spinon Fermi surface and provides a consistent explanation for the spectroscopic results in YbMgGaO4. Further connection of this spinon Fermi surface U (1 ) spin liquid with YbMgGaO4 and the future directions are discussed. Finally, our results may apply to other spin-orbit-coupled triangular lattice spin-liquid candidates, and more broadly, our general approach can be well extended to spin-orbit-coupled spin-liquid candidate materials.

  20. Sustainable Complex Triangular Cells for the Evaluation of CO2 Emissions by Individuals instead of Nations in a Scenario for 2030

    Directory of Open Access Journals (Sweden)

    Marcelo Sthel

    2013-05-01

    Full Text Available The concept of sustainable complex triangular cells may be applied to an individual of any human society. This concept was introduced in two recent articles. A case study was proposed to show the applicability of this new concept to Indian populations without contact with civilization and with a low environmental impact. Here we propose to apply this concept to a recent study, which claims that the concept of “common but differentiated responsibilities” refers to the emissions of individuals instead of nations. The income distribution of a country was used to estimate how its fossil fuel CO2 emissions are distributed among its citizens and, from that a global CO2 distribution was constructed. We propose the extension of the concept of complex triangular cells where its area would be equivalent to the CO2 emission per individual. In addition, a new three-dimensional geometric model for the regular hexagonal structure is offered in which the sharing of natural resources (human cooperation is employed to reduce CO2 emissions in two scenarios by 2030.

  1. Exact diagonalization study of the spin-1 two-dimensional J{sub 1}–J{sub 3} Heisenberg model on a triangular lattice

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, P., E-mail: rubin@fi.tartu.ee; Sherman, A.

    2014-11-07

    The spin-1 Heisenberg model on a triangular lattice with the ferromagnetic nearest-neighbor and antiferromagnetic third-nearest-neighbor exchange interactions, J{sub 1}=−(1−p)J and J{sub 2}=pJ, J>0(0≤p≤1), is studied with the use of the SPINPACK code. This model is applicable for the description of the magnetic properties of NiGa{sub 2}S{sub 4}. The ground, low-lying excited state energies and spin-spin correlation functions have been found for lattices with N=16 and N=20 sites with the periodic boundary conditions. These results are in qualitative agreement with earlier authors' results obtained with Mori's projection operator technique. - Highlights: • The S=1J{sub 1}–J{sub 3} Heisenberg model on a triangular lattice is studied. • The ferromagnetic nearest and AF 3rd-nearest-neighbor couplings are considered. • The exact diagonalization study of finite lattices was done. • The SPINPACK code using Lanczos' method is used for calculations. • The obtained results are in agreement with those obtained by Mori's approach.

  2. The high temperature Ising model is a critical percolation model

    NARCIS (Netherlands)

    Meester, R.W.J.; Camia, F.; Balint, A.

    2010-01-01

    We define a new percolation model by generalising the FK representation of the Ising model, and show that on the triangular lattice and at high temperatures, the critical point in the new model corresponds to the Ising model. Since the new model can be viewed as Bernoulli percolation on a random

  3. High slot utilization systems for electric machines

    Science.gov (United States)

    Hsu, John S

    2009-06-23

    Two new High Slot Utilization (HSU) Systems for electric machines enable the use of form wound coils that have the highest fill factor and the best use of magnetic materials. The epoxy/resin/curing treatment ensures the mechanical strength of the assembly of teeth, core, and coils. In addition, the first HSU system allows the coil layers to be moved inside the slots for the assembly purpose. The second system uses the slided-in teeth instead of the plugged-in teeth. The power density of the electric machine that uses either system can reach its highest limit.

  4. Synthesis and magnetochemistry of heterometallic triangular FeLn(III) (Ln = La, Gd, Tb, Dy, and Ho) and FeY(III) complexes.

    Science.gov (United States)

    Singh, Namrata; Das Gupta, Sayak; Butcher, Raymond J; Christou, George

    2017-06-20

    A series of Fe2Ln (Ln = La, Gd, Tb, Dy and Ho) and Fe2Y complexes have been synthesized via metal substitution and characterized by single crystal X-ray diffraction. All the molecules are isostructural and have a Fe2LnO triangular core with the oxygen atom existing as an μ3-oxo(2-) anion. DC and AC magnetic susceptibility studies were performed on all the molecules. For Fe2Ln (Ln = Gd, La) and Fe2Y, the data were fitted to Van Vleck equations and the magnetic coupling constants were obtained. In all cases, the two Fe(iii) spins were found to be antiparallel to each other in the ground state leaving the heterometal to remain essentially uncoupled.

  5. Lubricant transport across the piston ring with flat and triangular lubrication injection profiles on the liner in large two-stroke marine diesel engines

    DEFF Research Database (Denmark)

    Overgaard, Hannibal Toxværd; Klit, Peder; Vølund, Anders

    2017-01-01

    A theoretical investigation of the lubricant transport across the top compression piston ring in a large two-stroke marine diesel engine is presented. A numerical model for solving Reynolds equation between the piston ring and cylinder liner based on the finite difference method in one dimension...... the lubricant transport across the piston ring, two different kinds of initial lubricant profile on the liner and two different kinds of load are investigated i.e. a flat profile and an approximated triangular profile as well as no load and a combustion load based on a combustion pressure profile. The impact...... has been made. The model includes force equilibrium of the piston ring, perturbation of Reynolds equation, and transient mass conservation. The model represents a new method of achieving mass conservation across the piston ring and between different time-dependent positions. For analyzing...

  6. Impurity states and the diamagnetic susceptibility of a donor in a GaAs/AlxGa1-xAs Triangular Quantum Well under hydrostatic pressure

    Science.gov (United States)

    Kalpana, Panneer Selvam; Jayakumar, Kalyanasundaram

    2017-11-01

    We study the effect of Γ-X band crossover due to the application of hydrostatic pressure of a hydrogenic donor confined in a Triangular GaAs/Al1-xGaxAs Quantum Well (TQW) for x = 0.3 and the diamagnetic susceptibility (χdia) for such an impurity in 1s and some few low lying excited states have been investigated. The Schrodinger equation has been solved using variational technique in the effective mass approximation. The results show that the diamagnetic susceptibility (χdia) of a hydrogenic donor abruptly increases at a particular pressure for 1s and 2p± states but a steady increase for 2s state as a function of applied pressure.

  7. Hyper thin 3D edge measurement of honeycomb core structures based on the triangular camera-projector layout & phase-based stereo matching.

    Science.gov (United States)

    Jiang, Hongzhi; Zhao, Huijie; Li, Xudong; Quan, Chenggen

    2016-03-07

    We propose a novel hyper thin 3D edge measurement technique to measure the profile of 3D outer envelope of honeycomb core structures. The width of the edges of the honeycomb core is less than 0.1 mm. We introduce a triangular layout design consisting of two cameras and one projector to measure hyper thin 3D edges and eliminate data interference from the walls. A phase-shifting algorithm and the multi-frequency heterodyne phase-unwrapping principle are applied for phase retrievals on edges. A new stereo matching method based on phase mapping and epipolar constraint is presented to solve correspondence searching on the edges and remove false matches resulting in 3D outliers. Experimental results demonstrate the effectiveness of the proposed method for measuring the 3D profile of honeycomb core structures.

  8. Measurements of the Atmospheric Electric Field through a Triangular Array and the Long-range Saharan Dust Electrification in Southern Portugal

    CERN Document Server

    Silva, H G; Pereira, S; Barbosa, S M; Nicoll, K; Pereira, M Collares; Harrison, R G

    2016-01-01

    Atmospheric electric field (AEF) measurements were carried out in three different sites forming a triangular array in Southern Portugal. The campaign was performed during the summer characterized by Saharan dust outbreaks; the 16th-17th July 2014 desert dust event is considered here. Evidence of long-range dust electrification is attributed to the air-Earth electrical current creating a positive space-charge inside of the dust layer. An increase of ~23 V/m is observed in AEF on the day of the dust event corresponding to space-charges of ~20-2 pCm-3 (charge layer thicknesses ~10-100 m). A reduction of AEF is observed after the dust event.

  9. Energy levels of triangular and hexagonal graphene quantum dots: A comparative study between the tight-binding and Dirac equation approach

    Science.gov (United States)

    Zarenia, M.; Chaves, A.; Farias, G. A.; Peeters, F. M.

    2011-12-01

    The Dirac equation is solved for triangular and hexagonal graphene quantum dots for different boundary conditions in the presence of a perpendicular magnetic field. We analyze the influence of the dot size and its geometry on their energy spectrum. A comparison between the results obtained for graphene dots with zigzag and armchair edges, as well as for infinite-mass boundary condition, is presented and our results show that the type of graphene dot edge and the choice of the appropriate boundary conditions have a very important influence on the energy spectrum. The single-particle energy levels are calculated as a function of an external perpendicular magnetic field that lifts degeneracies. Comparing the energy spectra obtained from the tight-binding approximation to those obtained from the continuum Dirac equation approach, we verify that the behavior of the energies as a function of the dot size or the applied magnetic field are qualitatively similar, but in some cases quantitative differences can exist.

  10. Optical design of GaN/In(x)Ga(1-x)N/cSi tandem solar cells with triangular diffraction grating.

    Science.gov (United States)

    Lin, Leo Jyun-Hong; Chiou, Yih-Peng

    2015-06-01

    Optical design in enhancing optical absorption of group-III-nitride- and multiple quantum well-based GaN/InxGa1-xN/cSi dual-junction tandem solar cells with triangular diffraction grating is simulated and optimized by using combined two-dimensional rigorous coupled wave analysis and transfer matrix methods. This paper thoroughly examines these phenomena of optical absorption affected by antireflection coatings, multiple thin-film layers and diffraction gratings with the integrated perspectives of semiconductor physics and electromagnetic theory for the first time. An improvement of 58% in absorption compared to the prototype SC is obtained which means more than 80% of incoming light (hυ > EgSi) can be harvested in this thin-film (< 4 μm in total) design.

  11. Coupling between Spin and Charge Order Driven by Magnetic Field in Triangular Ising System LuFe2O4+δ

    Directory of Open Access Journals (Sweden)

    Lei Ding

    2018-02-01

    Full Text Available We present a study of the magnetic-field effect on spin correlations in the charge ordered triangular Ising system LuFe2O4+δ through single crystal neutron diffraction. In the absence of a magnetic field, the strong diffuse neutron scattering observed below the Neel temperature (TN = 240 K indicates that LuFe2O4+δ shows short-range, two-dimensional (2D correlations in the FeO5 triangular layers, characterized by the development of a magnetic scattering rod along the 1/3 1/3 L direction, persisting down to 5 K. We also found that on top of the 2D correlations, a long range ferromagnetic component associated with the propagation vector k1 = 0 sets in at around 240 K. On the other hand, an external magnetic field applied along the c-axis effectively favours a three-dimensional (3D spin correlation between the FeO5 bilayers evidenced by the increase of the intensity of satellite reflections with propagation vector k2 = (1/3, 1/3, 3/2. This magnetic modulation is identical to the charge ordered superstructure, highlighting the field-promoted coupling between the spin and charge degrees of freedom. Formation of the 3D spin correlations suppresses both the rod-type diffuse scattering and the k1 component. Simple symmetry-based arguments provide a natural explanation of the observed phenomenon and put forward a possible charge redistribution in the applied magnetic field.

  12. Surface-Enhanced Raman Spectroscopy of Dye and Thiol Molecules Adsorbed on Triangular Silver Nanostructures: A Study of Near-Field Enhancement, Localization of Hot-Spots, and Passivation of Adsorbed Carbonaceous Species

    Directory of Open Access Journals (Sweden)

    Manuel R. Gonçalves

    2012-01-01

    Full Text Available Surface-enhanced Raman spectroscopy (SERS of thiols and dye molecules adsorbed on triangular silver nanostructures was investigated. The SERS hot-spots are localized at the edges and corners of the silver triangular particles. AFM and SEM measurements permit to observe many small clusters formed at the edges of triangular particles fabricated by nanosphere lithography. Finite-element calculations show that near-field enhancements can reach values of more than 200 at visible wavelengths, in the gaps between small spherical particles and large triangular particles, although for the later no plasmon resonance was found at the wavelengths investigated. The regions near the particles showing strong near-field enhancement are well correlated with spatial localization of SERS hot-spots done by confocal microscopy. Silver nanostructures fabricated by thermal evaporation present strong and fast fluctuating SERS activity, due to amorphous carbon contamination. Thiols and dye molecules seem to be able to passivate the undesired SERS activity on fresh evaporated silver.

  13. Evaluation of the triangular fibrocartilage and the scapholunate and lunotriquetral ligaments in cadavers with low-field-strength extremity-only magnet. Comparison of available imaging sequences and macroscopic findings.

    Science.gov (United States)

    Ahn, J M; Brown, R R; Kwak, S M; Kang, H S; Muhle, C; Botte, M J; Trudell, D; Haghighi, P; Resnick, D

    1998-07-01

    The authors assessed the ability of a low-field-strength extremity-only magnet to provide visualization of the triangular fibrocartilage and the scapholunate and lunotriquetral ligaments. Twelve human wrists were examined with a 0.2 T extremity-only magnet. T1-weighted spin echo, proton density-weighted, and T2-weighted turbo spin echo, short-tau inversion recovery, and three-dimensional gradient recalled echo images were acquired, and sections of the specimens were then made that corresponded to the magnetic resonance images. Masked imaging analyses were correlated with macroscopic and limited histopathologic findings. Low-field-strength extremity-only magnet allowed consistent visualization of the triangular fibrocartilage and accurate assessment of a small number of complete tears of the triangular fibrocartilage. The scapholunate ligaments in all cases were identified using a combination of imaging sequences. Consistent visualization of the lunotriquetral ligament with a low-field-strength extremity magnet was difficult. Magnetic resonance imaging with a low-field-strength extremity-only magnet can be used to visualize the triangular fibrocartilage and the scapholunate ligament, but not the lunotriquetral ligament.

  14. Photo-degradation of high efficiency fullerene-free polymer solar cells.

    Science.gov (United States)

    Upama, Mushfika Baishakhi; Wright, Matthew; Mahmud, Md Arafat; Elumalai, Naveen Kumar; Mahboubi Soufiani, Arman; Wang, Dian; Xu, Cheng; Uddin, Ashraf

    2017-12-07

    Polymer solar cells are a promising technology for the commercialization of low cost, large scale organic solar cells. With the evolution of high efficiency (>13%) non-fullerene polymer solar cells, the stability of the cells has become a crucial parameter to be considered. Among the several degradation mechanisms of polymer solar cells, burn-in photo-degradation is relatively less studied. Herein, we present the first systematic study of photo-degradation of novel PBDB-T:ITIC fullerene-free polymer solar cells. The thermally treated and as-prepared PBDB-T:ITIC solar cells were exposed to continuous 1 sun illumination for 5 hours. The aged devices exhibited rapid losses in the short-circuit current density and fill factor. The severe short-circuit current and fill factor burn in losses were attributed to trap mediated charge recombination, as evidenced by an increase in Urbach energy for aged devices.

  15. Morphological Control for Highly Efficient Inverted Polymer Solar Cells Via the Backbone Design of Cathode Interlayer Materials

    OpenAIRE

    Zhang, Wenjun; Wu, Yulei; Bao, Qinye; Gao, Feng; Fang, Junfeng

    2014-01-01

    Two alcohol-soluble organic molecules are synthesized and introduced into inverted organic solar cells as the cathode interlayer. A power conversion efficiency as high as 9.22% is obtained by using the more hydrophobic molecule FTBTF-N as the cathode interlayer. Morphological studies suggest that design of the backbone can help to enhance short-circuit current density and fill factor. Funding Agencies|National Natural Science Foundation of China [51273208]; China Postdoctoral Science Foun...

  16. One-year outcomes after minimally invasive sacroiliac joint fusion with a series of triangular implants: a multicenter, patient-level analysis

    Directory of Open Access Journals (Sweden)

    Sachs D

    2014-08-01

    Full Text Available Donald Sachs,1 Robyn Capobianco,2 Daniel Cher,2 Timothy Holt,3 Mukund Gundanna,4 Timothy Graven,5 A Nick Shamie,6 John Cummings Jr7 1Center for Spinal Stenosis and Neurologic Care, Lakeland, FL, 2SI-BONE, Inc., San Jose, CA, 3Montgomery Spine Center, Montgomery, AL, 4Brazos Spine, College Station, TX, 5SSM Orthopedics, Wentzville, MO, 6UCLA Spine Center, Santa Monica, CA, 7Community Neurosurgical Care, Indianapolis, IN, USA Background: Sacroiliac joint (SI pain is an often-overlooked cause of lower-back pain, due in part to a lack of specific findings on radiographs and a symptom profile similar to other back-related disorders. A minimally invasive surgical (MIS approach to SI joint fusion using a series of triangular, titanium plasma spray-coated implants has shown favorable outcomes in patients with SI joint pain refractory to conservative care. The aim of this study was to provide a multicenter experience of MIS SI joint fusion using a patient-level analysis. Patients and methods: We report a patient-level analysis from 144 patients with a mean of 16 months postoperative follow-up. Demographic information, perioperative measures, complications, and clinical outcomes using a visual analog scale for pain were collected prospectively. Random-effects regression models were used to account for intersite variability. Results: The mean age was 58 years, 71% of patients were female, and 62% had a history of lumbar spinal fusion. Mean (95% confidence interval [CI] operative time was 73 minutes (25.4–118, blood loss was minimal, and hospital stay was 0.8 days (0.1–1.5. At follow-up, mean (95% CI visual analog scale pain scores improved by 6.1 points (5.7–6.6. Substantial clinical benefit, defined as a decrease in pain by >2.5 points or a score of 3.5 or less, was achieved in 91.9% of patients (95% CI 83.9%–96.1%, and 96% (95% CI 86.3%–98.8% of patients indicated they would have the same surgery again. Conclusion: When conservative measures

  17. High Reynolds Number Micro-Bubble and Polymer Drag Reduction Experiments

    Science.gov (United States)

    2008-01-01

    test model. Appendix A: Smooth-Flat-Plate Turbulent Boundary Layer Measurements at High Reynolds Number Ghanem F. Oweis’, Eric S. Winkel’, James M...a 15’-full-angle triangular wedge of 0.6- m length that was terminated at 25 mm thickness with 400 bevel angle. This asymmetric trailing edge design

  18. A New High-Order Spectral Difference Method for Simulating Viscous Flows on Unstructured Grids with Mixed Elements

    Energy Technology Data Exchange (ETDEWEB)

    Li, Mao; Qiu, Zihua; Liang, Chunlei; Sprague, Michael; Xu, Min

    2017-01-13

    In the present study, a new spectral difference (SD) method is developed for viscous flows on meshes with a mixture of triangular and quadrilateral elements. The standard SD method for triangular elements, which employs Lagrangian interpolating functions for fluxes, is not stable when the designed accuracy of spatial discretization is third-order or higher. Unlike the standard SD method, the method examined here uses vector interpolating functions in the Raviart-Thomas (RT) spaces to construct continuous flux functions on reference elements. Studies have been performed for 2D wave equation and Euler equa- tions. Our present results demonstrated that the SDRT method is stable and high-order accurate for a number of test problems by using triangular-, quadrilateral-, and mixed- element meshes.

  19. Pt-Al/sub 2/O/sub 3/ selective cermet coatings for high temperature photothermal conversion

    Energy Technology Data Exchange (ETDEWEB)

    Sella, C.; Vien, T.K.; Lafait, J.; Berthier, S.

    1982-04-30

    Preliminary results obtained with Pt-Al/sub 2/O/sub 3/ cermets prepared by cosputtering onto stainless steel substrates are presented. The reflectivity of the coatings is measured in the spectral range 0.35-15 ..mu..m for various platinum volume filling factors and thicknesses. From the variations in the reflectivity and in the electrical resistivity with the temperature of annealing in air the stability of the cermets up to 500/sup 0/C is found to be good. Very thin films (about 600 A) with a platinum volume filling factor q close to the percolation composition (qapprox. equal to0.37) exhibit a selective profile well suited to photothermal conversion at high temperatures.

  20. Hydrodynamics of triangular-grid arrays of floating point-absorber wave energy converters with inter-body and bottom slack-mooring connections

    Energy Technology Data Exchange (ETDEWEB)

    Vicente, Pedro C.; Falcao, Antonio F. de O.; Gato, Luiz M.C. [IDMEC, Instituto Superior Tecnico, Technical University of Lisbon, 1049-001 Lisboa (Portugal); Justino, Paulo A.P. [Laboratorio Nacional de Energia e Geologia, 1649-038 Lisboa (Portugal)

    2009-07-01

    It may be convenient that dense arrays of floating point absorbers are spread-moored to the sea bottom through only some of their elements (possibly located in the periphery), while the other array elements are prevented from drifting and colliding with each other by connections to adjacent elements. An array of identical floating point absorbers located at the grid points of an equilateral triangular grid is considered in the paper. A spread set of slack-mooring lines connect the peripheric floaters to the bottom. A weight is located at the centre of each triangle whose function is o pull the three floaters towards each other and keep the inter-body moorings lines under tension. The whole system - buoys, moorings and power take-off systems - is assumed linear, so that a frequency domain analysis may be employed. Hydrodynamic interference between the oscillating bodies is neglected. Equations are presented for a set of three identical point absorbers. This is then extended to more complex equilateral iriangular grid arrays. Results from numerical simulations, with regular and irregular waves, are presented for the motions and power absorption of hemispherical converters in arrays of three and seven elements and different mooring and power take-off parameters, and wave incidence angles. Comparisons are given with the unmoored and independently-moored buoy situations.

  1. Heat transfer and pressure drop characteristics of the tube bank fin heat exchanger with fin punched with flow redistributors and curved triangular vortex generators

    Science.gov (United States)

    Liu, Song; Jin, Hua; Song, KeWei; Wang, LiangChen; Wu, Xiang; Wang, LiangBi

    2017-10-01

    The heat transfer performance of the tube bank fin heat exchanger is limited by the air-side thermal resistance. Thus, enhancing the air-side heat transfer is an effective method to improve the performance of the heat exchanger. A new fin pattern with flow redistributors and curved triangular vortex generators is experimentally studied in this paper. The effects of the flow redistributors located in front of the tube stagnation point and the curved vortex generators located around the tube on the characteristics of heat transfer and pressure drop are discussed in detail. A performance comparison is also carried out between the fins with and without flow redistributors. The experimental results show that the flow redistributors stamped out from the fin in front of the tube stagnation points can decrease the friction factor at the cost of decreasing the heat transfer performance. Whether the combination of the flow redistributors and the curved vortex generators will present a better heat transfer performance depends on the size of the curved vortex generators. As for the studied two sizes of vortex generators, the heat transfer performance is promoted by the flow redistributors for the fin with larger size of vortex generators and the performance is suppressed by the flow redistributors for the fin with smaller vortex generators.

  2. Accumulation and interparticle connections of triangular Ag-coated Au nanoprisms by oil-coating method for surface-enhanced Raman scattering applications

    Science.gov (United States)

    Noda, Yuta; Asaka, Toru; Fudouzi, Hiroshi; Hayakawa, Tomokatsu

    2018-03-01

    To examine the optical responses of surface-enhanced Raman scattering (SERS) for tuned plasmonic nanoparticles, triangular Ag-coated Au (Au@Ag) nanoprisms with different sizes were separately synthesized, which were well controlled in their size (edge-length) and localized surface plasmon resonance (LSPR) wavelength (69.0 ± 8.4 to 173.8 ± 25.6 nm in size and 662-943 nm in LSPR wavelength). The mechanism of Ag shell formation on the Au nanoprisms was also studied with scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDS). The Au@Ag nanoprisms were immobilized by covering a colloidal solution containing the nanoprisms with silicone oil and evaporating the solvent in the oil (oil-coating method) so as to form a layer of accumulated plasmonic Au@Ag nanoprisms that had LSPR peak wavelengths tuned from 839 to 1182 nm. The accumulation conditions were analyzed by field-emission scanning electron microscopy (FE-SEM) and a Raman mapping technique. The Au@Ag nanoprisms under excitation at 632.8 nm exhibited higher SERS signals of rhodamine 6G, and SERS-mapped images of the novel immobilized films were obtained at different magnifications. It was concluded that accumulated Au@Ag nanoprisms undergoing tip-planar interconnections could produce enhanced local fields, resulting in higher SERS signals.

  3. Prediction of two-dimensional d-block elemental materials with normal honeycomb, triangular-dodecagonal, and square-octagonal structures from first principles

    Science.gov (United States)

    Zhou, Baozeng; Dong, Shengjie; Wang, Xiaocha; Zhang, Kailiang

    2017-10-01

    By first-principles calculations, we investigated the electronic structures and magnetic properties of several tetravalent transition-metal monolayers with normal honeycomb, triangular-dodecagonal, and square-octagonal structures by considering the effects of spin-orbit coupling and electronic strong correlation of d orbitals. For both standard and corrected approaches, spin-polarized Dirac points contributed by d states appear in the monolayers with hexagonal lattice (honeycomb and 3-12 lattices), but for 4-8 lattices, Dirac points disappear, demonstrating that specific symmetries are required for forming Dirac cones. By adding the on-site Coulomb repulsion, the electronic correlation of d orbital is enhanced and thus the electronic localization increases, aggravating the spin splitting. For Hf3-12, the coexistence of massless Dirac fermions and massive heavy fermions is found. Moreover, the spin-orbit coupling destroys the degeneracy of two bands at K points, and the largest gap opening of 214 meV appears in Hf4-8 due to both Coulomb repulsion and spin-orbit coupling. Our results demonstrate that the spin splitting and gap opening depend on the lattice symmetry, bond length, electronic strong correlation, and spin-orbit coupling. These predicted structures provide new choices in synthesizing two-dimensional transition-metal materials, which has the potential applications in spintronic devices, quantum computation, hydrogen storage, and catalytic chemistry.

  4. Adaptive thresholding with inverted triangular area for real-time detection of the heart rate from photoplethysmogram traces on a smartphone.

    Science.gov (United States)

    Jiang, Wen Jun; Wittek, Peter; Zhao, Li; Gao, Shi Chao

    2014-01-01

    Photoplethysmogram (PPG) signals acquired by smartphone cameras are weaker than those acquired by dedicated pulse oximeters. Furthermore, the signals have lower sampling rates, have notches in the waveform and are more severely affected by baseline drift, leading to specific morphological characteristics. This paper introduces a new feature, the inverted triangular area, to address these specific characteristics. The new feature enables real-time adaptive waveform detection using an algorithm of linear time complexity. It can also recognize notches in the waveform and it is inherently robust to baseline drift. An implementation of the algorithm on Android is available for free download. We collected data from 24 volunteers and compared our algorithm in peak detection with two competing algorithms designed for PPG signals, Incremental-Merge Segmentation (IMS) and Adaptive Thresholding (ADT). A sensitivity of 98.0% and a positive predictive value of 98.8% were obtained, which were 7.7% higher than the IMS algorithm in sensitivity, and 8.3% higher than the ADT algorithm in positive predictive value. The experimental results confirmed the applicability of the proposed method.

  5. Variety of valence bond states formed of frustrated spins on triangular lattices based on a two-level system Pd(dmit2

    Directory of Open Access Journals (Sweden)

    Masafumi Tamura and Reizo Kato

    2009-01-01

    Full Text Available Recent studies on the physical properties of the triangular system based on the Pd(dmit2 salts (dmit=1,3-dithiole-2-thione-4,5-dithiolate are reviewed. Quantum chemical architectures of the Pd(dmit2 molecule and its dimer are introduced with emphasis on the strong dimerization of a two-level system, which provides unique physical properties of the salts. The magnetic properties are outlined in view of the magneto-structural correlation specific to the frustrated spin systems. Some newly discovered ground states and their origins are discussed, for which the valence bond formation plays a key role. Among them, the two-level structure is crucial for the novel charge-separated state found in two salts. The valence bond ordering, similar to the spin-Peierls transition, has been found in a two-dimensional frustrated spin system. The physical aspects and possible relation to the pressure-induced superconductivity are discussed.

  6. Negative refractive behaviors of 2D triangular-lattice photonic crystals by structure of SiO2/TiO2 layers

    Science.gov (United States)

    Li, Mengxue; Liu, Mengnan; Jiang, Chengyi; Liu, Tongtong; Sun, Peng; Wan, Yong

    2018-01-01

    In this paper, we propose a two-dimensional (2-D) triangular lattice photonic crystal plate by close-packed SiO2/ TiO2 layers with the stacking mode of ABABABA. By using the finite-difference time-domain (FDTD) method, negative refraction of a single Gaussian beam incident plate with different angles are respectively demonstrated; clear image spots of a point source with normalized frequency ω=0.3605(2πc/a) vertical incident media plate are obtained in the image plane. It can be found that the imaging properties are as same as the isotropic homogeneous medium with refractive index n=-1. The measurement results show that when the distance between the image and the upper surface of the sample V is 5.12a, 3.09a and 1.15a, the distance between the source and the lower surface of the sample U is a, 3a and 5a, respectively. This means that the sum of U and V is mostly equal to the thickness of the plate L and the negative effect of near-perfect lens is realized. This proposed structure with negative refraction properties may have great applications for the design of photonic crystal focusing devices.

  7. One stage resection of spontaneous rupture of hepatocellular carcinoma in the triangular ligament with diaphragm invasion: case report and review of the literature

    Directory of Open Access Journals (Sweden)

    Park Kwang-Kuk

    2012-09-01

    Full Text Available Abstract A spontaneous rupture of hepatocellular carcinoma (HCC can lead to extensive hemorrhage and is a rare but life-threatening event. A 58-year-old male patient with no history of trauma presented at our institution with severe epigastric pain and abdominal distension for 6 h. His blood pressure was a 60/40 mmHg, and pulse rate was 132/min. Abdominal contrast enhanced computed tomography (CT imaging revealed a ruptured mass under the left diaphragm and fluid collection in the upper abdomen, flanks and pelvic cavity. Exploratory laparotomy confirmed the presence of an active bleeding tumor in the triangular ligament invading into the diaphragm. The tumor was resected with an appropriate diaphragm margin. The resected tumor was 5 cm in diameter and pathologically identified as hepatocellular carcinoma with a negative surgical margin. This case report shows that ruptured hepatocellular carcinoma should be considered in the differential diagnosis of non-traumatic hemoperitoneum. And it is necessary to set a surgical plan for unpredictable HCC rupture with direct diaphragm invasion.

  8. Zero, minimum and maximum relative radial acceleration for planar formation flight dynamics near triangular libration points in the Earth-Moon system

    Science.gov (United States)

    Salazar, F. J. T.; Masdemont, J. J.; Gómez, G.; Macau, E. E.; Winter, O. C.

    2014-11-01

    Assume a constellation of satellites is flying near a given nominal trajectory around L4 or L5 in the Earth-Moon system in such a way that there is some freedom in the selection of the geometry of the constellation. We are interested in avoiding large variations of the mutual distances between spacecraft. In this case, the existence of regions of zero and minimum relative radial acceleration with respect to the nominal trajectory will prevent from the expansion or contraction of the constellation. In the other case, the existence of regions of maximum relative radial acceleration with respect to the nominal trajectory will produce a larger expansion and contraction of the constellation. The goal of this paper is to study these regions in the scenario of the Circular Restricted Three Body Problem by means of a linearization of the equations of motion relative to the periodic orbits around L4 or L5. This study corresponds to a preliminar planar formation flight dynamics about triangular libration points in the Earth-Moon system. Additionally, the cost estimate to maintain the constellation in the regions of zero and minimum relative radial acceleration or keeping a rigid configuration is computed with the use of the residual acceleration concept. At the end, the results are compared with the dynamical behavior of the deviation of the constellation from a periodic orbit.

  9. Heading to 1 kW levels with laser bars of high-efficiency and emission wavelength around 880 nm and 940 nm

    Science.gov (United States)

    Pietrzak, A.; Woelz, M.; Huelsewede, R.; Zorn, M.; Hirsekorn, O.; Meusel, J.; Kindsvater, A.; Schröder, M.; Bluemel, V.; Sebastian, J.

    2015-03-01

    High-power quasi-CW laser bars are of great interest as pump sources of solid-state lasers generating high-energy ultrashort pulses for high energy projects. These applications require a continuous improvement of the laser diodes for reliable optical output powers and simultaneously high electrical-to-optical power efficiencies. An overview is presented of recent progress at JENOPTIK in the development of commercial quasi-CW laser bars emitting around 880 nm and 940 nm optimized for peak performance. At first, performances of 1.5 mm long laser bars with 75% fill-factor are presented. Both, 880 nm and 940 nm laser bars deliver reliable power of 500 W with wall-plug-efficiencies (WPE) cavity bars with 50% fill-factor based on an optimized laser structure for strong carrier confinement and low resistivity were measured. We report an output power of 0.8 kW at 0.8 A with <60% conversion efficiency (52% WPE). By increasing the fill-factor of the bars a further improvement of the WPE at high currents is expected.

  10. High-Surface-Area Architectures for Improved Charge Transfer Kinetics at the Dark Electrode in Dye-Sensitized Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Hoffeditz, William L.; Katz, Michael J.; Deria, Pravas; Martinson, Alex B. F.; Pellin, Michael J.; Farha, Omar K.; Hupp, Joseph T.

    2014-06-11

    Dye-sensitized solar cell (DSC) redox shuttles other than triiodide/iodide have exhibited significantly higher charge transfer resistances at the dark electrode. This often results in poor fill factor, a severe detriment to device performance. Rather than moving to dark electrodes of untested materials that may have higher catalytic activity for specific shuttles, the surface area of platinum dark electrodes could be increased, improving the catalytic activity by simply presenting more catalyst to the shuttle solution. A new copper-based redox shuttle that experiences extremely high charge-transfer resistance at conventional Pt dark electrodes yields cells having fill-factors of less than 0.3. By replacing the standard Pt dark electrode with an inverse opal Pt electrode fabricated via atomic layer deposition, the dark electrode surface area is boosted by ca. 50-fold. The resulting increase in interfacial electron transfer rate (decrease in charge-transfer resistance) nearly doubles the fill factor and therefore the overall energy conversion efficiency, illustrating the utility of this high-area electrode for DSCs.

  11. Existence of Resonance Stability of Triangular Equilibrium Points in Circular Case of the Planar Elliptical Restricted Three-Body Problem under the Oblate and Radiating Primaries around the Binary System

    Directory of Open Access Journals (Sweden)

    A. Narayan

    2014-01-01

    Full Text Available This paper analyzes the existence of resonance stability of the triangular equilibrium points of the planar elliptical restricted three-body problem when both the primaries are oblate spheroid as well as the source of radiation under the particular case, when e=0. We have derived Hamiltonian function describing the motion of infinitesimal mass in the neighborhood of the triangular equilibrium solutions taken as a convergent series. Hamiltonian function for the system has been derived and also expanded in powers of the generalized components of momenta. We have used canonical transformation to make the Hamiltonian function independent of true anomaly. The most interesting and distinguishable results of this study are establishing the relation for determining the range of stability at and near the resonance ω2=1/2 around the binary system.

  12. Thermal performance of periodic serpentine channels with semi–circular and triangular cross–sections / Fourie J.H.

    OpenAIRE

    Fourie, Jan Hendrik.

    2011-01-01

    Printed Circuit Heat Exchangers (PCHE's) are very efficient compact exchangers considered as recuperators in the Brayton cycle of new generation high temperature reactor designs. The heat exchangers use multiple plate layers containing tortuous micro–channels to enhance the heat transfer between the working fluids. Understanding the flow phenomena and its effects on heat transfer inside the channels would ultimately lead to improved exchanger designs. A numerical study was conducted on ...

  13. Simulação estocástica de atributos do clima e da produtividade potencial de milho utilizando-se distribuição triangular Stochastic simulation of climate parameters and potential productivity of maize using triangular distribution

    Directory of Open Access Journals (Sweden)

    Janilson Pinheiro de Assis

    2006-03-01

    Full Text Available O objetivo deste trabalho foi simular a produtividade potencial da cultura de milho, pelo método de Monte Carlo, utilizando um modelo agrometeorológico estocástico. O experimento foi conduzido em Piracicaba, SP, a 22º42'30''S, 47º38'30''W, e altitude de 546 m, o clima da região é do tipo Cwa (tropical úmido. Foram utilizados os valores médios diários de temperatura (de 1917 a 2002 e radiação solar global (de 1978 a 2002. Para comparar os dados reais com os simulados, foram utilizados índices de desempenho estatístico. Observou-se que os modelos probabilísticos, desenvolvidos para a simulação de dados médios diários de temperatura e de radiação solar global, geraram valores semelhantes aos observados por meio da distribuição triangular, a qual pode ser utilizada em modelo estocástico, para previsão da produtividade potencial de milho, nas diferentes épocas de semeadura.The objective of this work was to simulate the potential productivity of maize, through Monte Carlo method, using an agrometeorological stochastic model. The experiment was conduct in Piracicaba, State of São Paulo, Brazil, at 22º42'30''S, 47º38'30''W, and 546 m altitude, the climate of the region is Cwa type, tropical humid. Daily average values of temperature (from 1917 to 2002 and global solar radiation (from 1978 to 2002 were used. Statistical performance index was used to compare observed and simulated data. The probabilistic models developed to simulate temperature and solar radiation averages produced similar values to observed data through triangular distribution, and it can be used in stochastic models to predict maize potential productivity in different dates of sowing.

  14. High Current Planar Transformer for Very High Efficiency Isolated Boost DC-DC Converters

    DEFF Research Database (Denmark)

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

    2014-01-01

    This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac......-resistance and transformer leakage inductance. Design and optimization procedures are validated based on an experimental prototype of a 6 kW dcdc isolated full bridge boost converter developed on fully planar magnetics. The prototype is rated at 30-80 V 0-80 A on the low voltage side and 700-800 V on the high voltage side...... with a peak efficiency of 97.8% at 80 V 3.5 kW. Results highlights that thick copper windings can provide good performance at low switching frequencies due to the high transformer filling factor. PCB windings can also provide very high efficiency if stacked in parallel utilizing the transformer winding window...

  15. Arthroscopic repair of triangular fibrocartilage tears: a biomechanical comparison of a knotless suture anchor and the traditional outside-in repairs.

    Science.gov (United States)

    Desai, Mihir J; Hutton, William C; Jarrett, Claudius D

    2013-11-01

    To compare the biomechanical strength of a knotless suture anchor repair and the traditional outside-in repair of peripheral triangular fibrocartilage complex (TFCC) tears in a cadaveric model. We dissected the distal ulna and TFCC from 6 matched cadaveric wrist pairs and made iatrogenic complete peripheral TFCC tears in each wrist. In 6 wrists, the TFCC tears were repaired using the standard outside-in technique using 2 2-0 polydioxane sutures placed in a vertical mattress fashion. In the other 6 wrists, we repaired the TFCC tears using mini-pushlock suture anchors to the fovea. The strength of the repairs was then determined using a materials testing machine with the load placed across the repair site. We loaded the repairs until a gap of 2 mm formed across the repair site, and then subsequently loaded them to failure. Thus, for each repair we obtained the load at 2-mm gap formation, load to failure, and mode of failure. At the 2-mm gap formation, the suture anchor repairs were statistically stronger than the outside-in repairs. For load to failure, the suture anchor repairs were also statistically stronger than the outside-in repairs. Failure in both techniques occurred most commonly as suture pull-out from the soft tissues. The all-arthroscopic suture anchor TFCC repair was biomechanically stronger than an outside-in repair. The suture anchor technique allows for repair of both the superficial and deep layers of the articular disk directly to bone, restoring the native TFCC anatomy. By being knotless, the suture anchor repair avoids irritation to the surrounding soft tissues by suture knots. Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  16. 3-T direct MR arthrography of the wrist: Value of finger trap distraction to assess intrinsic ligament and triangular fibrocartilage complex tears

    Energy Technology Data Exchange (ETDEWEB)

    Cerny, Milena; Marlois, Romain [Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Rue du Bugnon 46, 1011 Lausanne (Switzerland); Theumann, Nicolas [Institute of Radiology, Clinique Hirslanden Bois-Cerf, Avenue d’Ouchy 31, 1006 Lausanne (Switzerland); Bollmann, Christof; Wehrli, Laurent [Department of Plastic and Hand Surgery, Clinique Longeraie and Centre Hospitalier Universitaire Vaudois, University of Lausanne, Avenue de la Gare 9, 1003 Lausanne (Switzerland); Richarme, Delphine [Institute of Radiology, Clinique Hirslanden Bois-Cerf, Avenue d’Ouchy 31, 1006 Lausanne (Switzerland); Meuli, Reto [Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Rue du Bugnon 46, 1011 Lausanne (Switzerland); Becce, Fabio, E-mail: fabio.becce@chuv.ch [Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Rue du Bugnon 46, 1011 Lausanne (Switzerland)

    2013-10-01

    Purpose: To determine the value of applying finger trap distraction during direct MR arthrography of the wrist to assess intrinsic ligament and triangular fibrocartilage complex (TFCC) tears. Materials and methods: Twenty consecutive patients were prospectively investigated by three-compartment wrist MR arthrography. Imaging was performed with 3-T scanners using a three-dimensional isotropic (0.4 mm) T1-weighted gradient-recalled echo sequence, with and without finger trap distraction (4 kg). In a blind and independent fashion, two musculoskeletal radiologists measured the width of the scapholunate (SL), lunotriquetral (LT) and ulna-TFC (UTFC) joint spaces. They evaluated the amount of contrast medium within these spaces using a four-point scale, and assessed SL, LT and TFCC tears, as well as the disruption of Gilula's carpal arcs. Results: With finger trap distraction, both readers found a significant increase in width of the SL space (mean Δ = +0.1 mm, p ≤ 0.040), and noticed more contrast medium therein (p ≤ 0.035). In contrast, the differences in width of the LT (mean Δ = +0.1 mm, p ≥ 0.057) and UTFC (mean Δ = 0 mm, p ≥ 0.728) spaces, as well as the amount of contrast material within these spaces were not statistically significant (p = 0.607 and ≥0.157, respectively). Both readers detected more SL (Δ = +1, p = 0.157) and LT (Δ = +2, p = 0.223) tears, although statistical significance was not reached, and Gilula's carpal arcs were more frequently disrupted during finger trap distraction (Δ = +5, p = 0.025). Conclusion: The application of finger trap distraction during direct wrist MR arthrography may enhance both detection and characterisation of SL and LT ligament tears by widening the SL space and increasing the amount of contrast within the SL and LT joint spaces.

  17. Vortex Generator Induced Flow in a High Re Boundary Layer

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Braud, C.; Coudert, S.

    2012-01-01

    Stereoscopic Particle Image Velocimetry measurements have been conducted in cross-planes behind three different geometries of Vortex Generators (VGs) in a high Reynolds number boundary layer. The VGs have been mounted in a cascade producing counter-rotating vortices and the downstream flow...... development was examined. Three VG geometries were investigated: rectangular, triangular and cambered. The various VG geometries tested are seen to produce different impacts on the boundary layer flow. Helical symmetry of the generated vortices is confirmed for all investigated VG geometries in this high...... Reynolds number boundary layer. From the parameters resulting from this analysis, it is observed at the most upstream measurement position that the rectangular and triangular VGs produce vortices of similar size, strength and velocity induction whilst the cambered VGs produce smaller and weaker vortices...

  18. High-Efficiency Dye-Sensitized Solar Cell with Three-Dimensional Photoanode

    KAUST Repository

    Tétreault, Nicolas

    2011-11-09

    Herein, we present a straightforward bottom-up synthesis of a high electron mobility and highly light scattering macroporous photoanode for dye-sensitized solar cells. The dense three-dimensional Al/ZnO, SnO2, or TiO 2 host integrates a conformal passivation thin film to reduce recombination and a large surface-area mesoporous anatase guest for high dye loading. This novel photoanode is designed to improve the charge extraction resulting in higher fill factor and photovoltage for DSCs. An increase in photovoltage of up to 110 mV over state-of-the-art DSC is demonstrated. © 2011 American Chemical Society.

  19. Triangular Numbers and Elliptic Curves

    NARCIS (Netherlands)

    Chahal, Jasbir S.; Top, Jaap

    1996-01-01

    Some arithmetic of elliptic curves and theory of elliptic surfaces is used to find all rational solutions (r, s, t) in the function field Q(m, n) of the pair of equations r(r + 1)/2 = ms(s + 1)/2 r(r + 1)/2 = nt(t + 1)/2. It turns out that infinitely many solutions exist. Several examples will be

  20. High-order adaptive methods for parabolic systems

    Science.gov (United States)

    Adjerid, S.; Flaherty, J. E.; Moore, P. K.; Wang, Y. J.

    1992-11-01

    We consider the adaptive solution of parabolic partial differential systems in one and two space dimensions by finite element procedures that automatically refine and coarsen computational meshes, vary the degree of the piecewise polynomial basis and, in one dimension, move the computational mesh. Two-dimensional meshes of triangular, quadrilateral, or a mixture of triangular and quadrilateral elements are generated using a finite quadtree procedure that is also used for data management. A posteriori estimates, used to control adaptive enrichment, are generated from the hierarchical polynomial basis. Temporal integration, within a method-of-lines framework, uses either backward difference methods or a variant of the singly implicit Runge-Kutta (SIRK) methods. A high-level user interface facilitates use of the adaptive software.

  1. Entanglement and magnetism in high-spin graphene nanodisks

    Science.gov (United States)

    Hagymási, I.; Legeza, Ö.

    2018-01-01

    We investigate the ground-state properties of triangular graphene nanoflakes with zigzag edge configurations. The description of zero-dimensional nanostructures requires accurate many-body techniques since the widely used density-functional theory with local density approximation or Hartree-Fock methods cannot handle the strong quantum fluctuations. Applying the unbiased density-matrix renormalization group algorithm we calculate the magnetization and entanglement patterns with high accuracy for different interaction strengths and compare them to the mean-field results. With the help of quantum information analysis and subsystem density matrices we reveal that the edges are strongly entangled with each other. We also address the effect of electron and hole doping and demonstrate that the magnetic properties of triangular nanoflakes can be controlled by an electric field, which reveals features of flat-band ferromagnetism. This may open up new avenues in graphene based spintronics.

  2. Surgical Treatment of Acute Grade III Medial Collateral Ligament Injury Combined With Anterior Cruciate Ligament Injury: Anatomic Ligament Repair Versus Triangular Ligament Reconstruction.

    Science.gov (United States)

    Dong, Jiangtao; Wang, Xiao Feng; Men, Xiaoqian; Zhu, Junjun; Walker, Garth N; Zheng, Xiao Zuo; Gao, Jin Bao; Chen, Baicheng; Wang, Fei; Zhang, Yingze; Gao, Shi Jun

    2015-06-01

    The purpose of this study was to evaluate the clinical results of medial collateral ligament (MCL) anatomic ligament repair (ALR) and triangular ligament reconstruction (TLR) in treating acute grade III MCL injury with respect to imaging and functional results. Between January 2009 and October 2011, a total of 69 patients with an acute grade III MCL tear combined with an anterior cruciate ligament tear were divided into 2 groups: those who underwent ALR and those who underwent TLR. Single-bundle anterior cruciate ligament reconstruction was also performed in all patients. A radiographic stress-position imaging test was performed to evaluate excessive medial opening of the knee. In addition, the Slocum test was carried out to assess anteromedial rotatory instability before surgery and at follow-up. The subjective symptoms and functional outcomes were evaluated preoperatively and postoperatively with International Knee Documentation Committee (IKDC) assessment. Sixty-four patients with a mean follow-up period of 34 months were included in the final analysis. The measurement results for medial opening at the last follow-up appointment decreased significantly from the pretreatment measurements and fell within the normal range, without a statistically significant difference between the 2 groups (P > .05). The overall incidence of anteromedial rotatory instability was reduced to 21.9% compared with 62.5% preoperatively. However, the incidence of anteromedial rotatory instability in the TLR group (9.4%) decreased significantly compared with that in the ALR group (34.4%) (P .05). The comparison of IKDC extension and flexion deficit scores between the 2 groups showed no significant differences. Eleven patients in the ALR group and 4 in the TLR group complained of medial knee pain. The comparison between the 2 groups showed no significant difference (P > .05). The clinical outcomes of this study showed that no major difference existed in the ALR and TLR groups based on IKDC

  3. Spin-valley skyrmions in graphene at filling factor ν =-1

    Science.gov (United States)

    Lian, Yunlong; Goerbig, Mark O.

    2017-06-01

    We model quantum Hall skyrmions in graphene monolayer at quarter filling by a theory of CP3 fields and study the energy minimizing skyrmions in the presence of valley pseudospin anisotropy and Zeeman coupling. We present a diagram of all types of skyrmions in a wide range of the anisotropy parameters. For each type of skyrmion, we visualize it on three Bloch spheres, and present the profiles of its texture on the graphene honeycomb lattice, thus providing references for the scanning-tunneling microscopy and spectroscopy imaging of spin-pseudospin textures in graphene monolayer in the quantum Hall regime. Besides the spin and pseudospin skyrmions for the corresponding degrees of freedom of an electron in the N =0 Landau level, we discuss two unusual types—the "entanglement skyrmion", the texture of which lies in the space of the entanglement of spin and pseudospin, as well as the "deflated pseudospin skyrmion" with partial entanglement. For all skyrmion types, we study the dependence of the energy and the size of a skyrmion on the anisotropy parameters and perpendicular magnetic field. We also propose three ways to modify the anisotropy energy, namely, the sample tilting, the substrate anisotropy, and the valley pseudospin analog of Zeeman coupling.

  4. Combination between [B-α-SiW9O34] unit and triangular inorganic Ni6 core under hydrothermal conditions: from monomer to rare dimer with malposed dodeca-nickel centers.

    Science.gov (United States)

    Yang, Lei; Huo, Yu; Niu, Jingyang

    2013-01-14

    The hydrothermal reactions of α-K(4)SiW(12)O(40) with NiCl(2)·6H(2)O yielded two unprecedented silicotungstates containing a triangular inorganic Ni(6) core. Furthermore, Na(2)[Ni(6)(μ(3)-OH)(3)(H(2)O)(9)SiW(9)O(34)](2)·17H(2)O (1) presents a rare dimer, in which two SiW(9) units sandwich double Ni(6) cores by W-O-Ni linking instead of conventional Ni-O-Ni.

  5. Magnetic properties of S = 1/2 quasi-triangular lattice materials: Cu(2(1-x))Zn(2x)(OH)3NO3/(C7H15COO)·mH2O.

    Science.gov (United States)

    Wu, J; Gangopadhyay, A K; Kanjanaboos, P; Solin, S A

    2010-08-25

    We have investigated the structural and magnetic properties of two classes of spin S = 1/2 antiferromagnetic quasi-triangular lattice materials: Cu(2(1-x))Zn(2x)(OH)(3)NO(3) (0 ≤ x ≤ 0.65) and its long chain organic derivatives Cu(2(1-x))Zn(2x)(OH)(3)(C(7)H(15)COO)·mH(2)O (0 ≤ x ≤ 0.29). The series of layered structure compounds constitute a substitutional magnetic system, in which spin S = 1/2Cu(2+) ions and nonmagnetic Zn(2+) ions are arranged on a two-dimensional quasi-triangular lattice. For the nitrate compounds we found that the substitution of Zn(2+) ions can continuously decrease the Néel temperature, T(N), but never completely remove the magnetic order. In addition, the frustration effect in these materials is suppressed by a three-dimensional interlayer interaction. On the other hand, the corresponding long chain alkyl carboxylic acid group of intercalated materials, Cu(2(1-x))Zn(2x)(OH)(3)(C(7)H(15)COO)·mH(2)O, show spin-glass-like behavior, which is caused by the interplay of geometric frustration and mixed sign interactions. A tentative explanation for these findings is proposed in terms of a cluster-glass picture.

  6. High-precision photometry by telescope defocusing - VII. The ultrashort period planet WASP-103

    DEFF Research Database (Denmark)

    Southworth, John; Mancini, L.; Ciceri, S.

    2015-01-01

    for these calculations. The planet has a Roche lobe filling factor of 0.58, leading to a significant asphericity; we correct its measured mass and mean density for this phenomenon. A high-resolution Lucky Imaging observation shows no evidence for faint stars close enough to contaminate the point spread function of WASP......-103. Our data were obtained in the Bessell $RI$ and the SDSS $griz$ passbands and yield a larger planet radius at bluer optical wavelengths, to a confidence level of 7.3 sigma. Interpreting this as an effect of Rayleigh scattering in the planetary atmosphere leads to a measurement of the planetary...

  7. Highly birefringent, highly negative dispersion compensating photonic crystal fiber.

    Science.gov (United States)

    Bala, Animesh; Chowdhury, Kanan Roy; Mia, Md Borhan; Faisal, Mohammad

    2017-09-01

    A triangular lattice dispersion compensating photonic crystal fiber is presented in this paper. The fiber produces high birefringence and operates at fundamental mode only. The full vector finite element method with a perfectly matched absorbing layer boundary condition is applied to investigate the guiding properties of the proposed fiber. The designed fiber demonstrates that it is possible to obtain a very large negative dispersion of -9486.1  ps/(nm·km) at 1550 nm wavelength with a negative dispersion more than -7000  ps/(nm·km) over the entire C-band (1530-1565 nm), which is suitable for broadband dispersion compensation. The birefringence is about 4.13×10(-2) at 1550 nm wavelength, which is also very high. All these properties make this fiber very suitable in the area of broadband dispersion compensation and polarization-maintaining applications.

  8. Discrete and polymeric heteronuclear constructs derived from triangular 2,2'-bipyrazine complexes of cis-a2Pt(II) (with a = NH3 or a2 = en).

    Science.gov (United States)

    Galstyan, Anzhela; Sanz Miguel, Pablo J; Weise, Katrin; Lippert, Bernhard

    2013-12-07

    cis-[Pta2(H2O)2](2+) (with a = NH3 or a2 = en) and 2,2'-bipyrazine (2,2'-bpz) react in water preferentially to cyclic, triangular complexes of composition [{cis-Pta2(2,2'-bpz-N4,N4')}3](6+) (a = NH3, 1a; a2 = en, 1b). In their C3-symmetric conformation (all bridging pyrazine rings adopt cisoid orientations with respect to the central C2-C2' bond), 1a and 1b provide three pairs of N1,N1' donor sites each, which are capable of chelating additional (hetero)metal ions. The latter can in turn bridge to other N1,N1' sites in an intermolecular fashion or simply complete their coordination spheres with other ligands (water, anions). Four previously not observed structural variants of heteronuclear (Pt(II), Cu(II); Pt(II), Ag(I); Pt(II), Cd(II)) constructs have now been isolated by us and are reported here: a decanuclear Pt6Cu4 complex, [{(en)Pt(2,2'-bpz)}3]2Cu4(H2O)6(NO3)20·11H2O (2) with the appearance of a paddle-wheel, a dodecanuclear Pt6Cu6 capsule with a Cu(2+) ion in its interior and additional Cu(2+) ions in its periphery giving a total composition of [{(en)Pt(2,2'-bpz)}3]2Cu11(NO3)34(H2O)18·3H2O (3), as well as two coordination polymers, {[{(en)Pt(2,2'-bpz)}3]Cd2(H2O)7}(SO4)5·{[Cd(H2O)6](SO4)}·15H2O (4) and [{cis-(NH3)2Pt(2,2'-bpz)}3]Ag(SiF6)3(BF4)·7H2O (5). The structures of these four compounds are dominated by host-guest interactions between the triangular metal vases of 1a and 1b and anions, respectively, as well as hydrogen bonding involving anions and water molecules and electrostatics. In aqueous solution considerable dissociation of the heteronuclear compounds 2-5 into the triangular Pt complexes 1 and the heterometal ions takes place. Preliminary AFM (atomic force microscopy) studies reveal that the +6 cations of 1a have a strong tendency to interact with double-stranded DNA with formation of condensed DNA states.

  9. Fabrication of a Highly Sensitive Single Aligned TiO2 and Gold Nanoparticle Embedded TiO2 Nano-Fiber Gas Sensor.

    Science.gov (United States)

    Nikfarjam, Alireza; Hosseini, Seyedsina; Salehifar, Nahideh

    2017-05-10

    In this research, a single-aligned nanofiber of pure TiO2 and gold nanoparticle (GNP)-TiO2 were fabricated using a novel electro-spinning procedure equipped with secondary electrostatic fields on highly sharp triangular and rectangular electrodes provided for gas sensing applications. The sol used for spinning nanofiber consisted of titanium tetraisopropoxide (C12H28O4Ti), acetic acid (CH3COOH), ethanol (C2H5OH), polyvinylpyrrolidone (PVP), and gold nanoparticle solution. FE-SEM, TEM, and XRD were used to characterize the single nanofiber. In triangular electrodes, the electrostatic voltage for aligning single nanofiber between electrodes depends on the angle tip of the electrode, which was around 1.4-2.1, 2-2.9, and 3.2-4.1 kV for 30°, 45°, and 60°, respectively. However, by changing the shape of the electrodes to rectangular samples and by increasing distance between electrodes from 100 to 200 μm, electro-spinning applied voltage decreased. Response of pure TiO2 single nanofiber sensor was measured for 30-200 ppb carbon monoxide gas. The triangular sample revealed better response and lower threshold than the rectangular sample. Adding appropriate amounts of GNP decreased the operating temperature and increased the responses. CO concentration threshold for the pure TiO2 and GNP-TiO2 triangular samples was about 5 ppb and 700 ppt, respectively.

  10. High peak power diode stacks for high energy lasers

    Science.gov (United States)

    Negoita, Viorel C.; Vethake, Thilo; Jiang, John; Roff, Robert; Shih, Ming; Duck, Richard; Bauer, Marc; Mite, Roberto; Boucke, Konstantin; Treusch, Georg

    2015-02-01

    High energy solid state lasers are being developed for fusion experiments and other research applications where high energy per pulse is required but the repetition rate is rather low, around 10Hz. We report our results on high peak power diode laser stacks used as optical pumps for these lasers. The stacks are based on 10 mm bars with 4 mm cavity length and 55% fill factor, with peak power exceeding 500 W per bar. These bars are stacked and mounted on a cooler which provides backside cooling and electrical insulation. Currently we mount 25 bars per cooler for a nominal peak power of 12.5 kW, but in principle the mounting scheme can be scaled to a different number of devices depending on the application. Pretesting of these bars before soldering on the cooler enables us to select devices with similar wavelength and thus we maintain tight control of the spectral width (FWHM less than 6 nm). Fine adjustments of the centroid wavelength can be done by means of temperature of the cooling fluid or bias current. The available wavelength range spans from 880 nm to 1000 nm, and the wavelength of the entire assembly of stacks can be controlled to within 0.5 nm of the target value, which makes these stacks suitable for pumping a variety of gain media. The devices are fast axis collimated, with over 95% power being collimated in 6 mrad (full angle). The slow axis divergence is 9° (full angle) for 95% power content.

  11. A new high pressure form of Ba{sub 3}NiSb{sub 2}O{sub 9}

    Energy Technology Data Exchange (ETDEWEB)

    Darie, Céline; Lepoittevin, Christophe; Klein, Holger; Kodjikian, Stéphanie; Bordet, Pierre; Colin, Claire V. [Institut Néel, Université Grenoble-Alpes, and Institut Néel, CNRS, Grenoble F−38042 (France); Lebedev, Oleg I. [Laboratoire CRISMAT, ENSICAEN UMR6508, 6 Bd Maréchal Juin, Caen Cedex 4 F−14050 (France); Deudon, Catherine; Payen, Christophe [Institut des Matériaux Jean Rouxel (IMN), UMR 6502, Université de Nantes, CNRS, Nantes Cedex 3 F−44322 (France)

    2016-05-15

    In the search of an experimental realization of quantum spin liquid phases we have synthesized polycrystalline samples of Ba{sub 3}NiSb{sub 2}O{sub 9} under high pressure–high temperature conditions. Combining X-ray powder diffraction, neutron powder diffraction and precession electron diffraction we show that the obtained phase isn't hexagonal as reported in the literature, but trigonal. This new structure shows triangular Ni planes, but only in domains of sizes of the order of 10 nm. It therefore is still interesting as a potential candidate for a quantum spin liquid. - Graphical abstract: Synthesis under high pressure of a new form of Ba{sub 3}NiSb{sub 2}O{sub 9} : a promising candidate for a quantum spin liquid. Triangular Ni-planes can effectively be present in this structure but only in domains of up to 10 nm in size.

  12. High performance PtSi linear and area focal plane arrays

    Science.gov (United States)

    Maddoux, Bob; Burt, Steve

    1990-09-01

    The operation, performance, and applications are set forth for linear and area focal plane arrays which use PtSi Schottky barrier diodes to image in the 1 to 5.5 micron spectral range. Two linear FPAs, with pixels spaced on 25 micron centers, are considered. A digital scan readout is used in these arrays. A discussion of a 128 by 128 element PtSi FPA follows, where a MOS/CTD readout structure is employed. The digital shift register addresses diode rows one by one due to the parallel connection of the MOS multiplexer switches in this device. Two bucket brigade charge transfer registers are utilized for signal readout. Lastly, a high fill factor, low noise 512 by 512 PtSi FPA is discussed, which uses a new line-addressed charge-accumulation (LACA) CCD in an interline transfer configuration and a multiple-readout horizontal register. The digital scan readout allows high sensitivity and signal levels. The second device and the LACA structure permit a high fill factor and charge handling capacity. The lower cost and higher resolution of the latter devices are underscored, and applications for all the FPAs are listed.

  13. Fusion: ultra-high-speed and IR image sensors

    Science.gov (United States)

    Etoh, T. Goji; Dao, V. T. S.; Nguyen, Quang A.; Kimata, M.

    2015-08-01

    Most targets of ultra-high-speed video cameras operating at more than 1 Mfps, such as combustion, crack propagation, collision, plasma, spark discharge, an air bag at a car accident and a tire under a sudden brake, generate sudden heat. Researchers in these fields require tools to measure the high-speed motion and heat simultaneously. Ultra-high frame rate imaging is achieved by an in-situ storage image sensor. Each pixel of the sensor is equipped with multiple memory elements to record a series of image signals simultaneously at all pixels. Image signals stored in each pixel are read out after an image capturing operation. In 2002, we developed an in-situ storage image sensor operating at 1 Mfps 1). However, the fill factor of the sensor was only 15% due to a light shield covering the wide in-situ storage area. Therefore, in 2011, we developed a backside illuminated (BSI) in-situ storage image sensor to increase the sensitivity with 100% fill factor and a very high quantum efficiency 2). The sensor also achieved a much higher frame rate,16.7 Mfps, thanks to the wiring on the front side with more freedom 3). The BSI structure has another advantage that it has less difficulties in attaching an additional layer on the backside, such as scintillators. This paper proposes development of an ultra-high-speed IR image sensor in combination of advanced nano-technologies for IR imaging and the in-situ storage technology for ultra-highspeed imaging with discussion on issues in the integration.

  14. Next generation 9xx/10xx nm high power laser diode bars for multi-kilowatt industrial applications

    Science.gov (United States)

    Commin, Paul; Todt, René; Krejci, Martin; Bättig, Rainer; Brunner, Reinhard; Lichtenstein, Norbert

    2013-02-01

    We report on the development of high power, 9xx-10xx nm laser diode bars for use in direct diode systems and for solidstate and fibre laser pumping with applications in industrial markets. For 1 cm wide bars on micro channel cooler (MCC) we have achieved a reliable output power of 250 W across the 900 nm - 1060 nm range. At this output power level we have achieved power conversion efficiencies of 65-66 % and 90 % power content slow axis beam divergence of ~6.5°. Results of a 6400 h life test show an average power degradation of 0.6 % per 1000 h at this operating power level. We will also show results of high power bars assembled on the new OCLARO conductive cooler, the BLM. This new cooler has a small footprint of 12.6 mm × 24.8 mm and is designed for lateral or vertical stacking of diodes in multi kilowatt systems but with the benefits associated with a conductive cooler. The thermal properties are shown to be the same as for a standard CS mount. 1 cm wide high fill factor bars and 0.5 cm wide low fill factor half bars assembled on the BLM operate at 63-64 % power conversion efficiency (PCE) with output powers of up to 250 W and 150 W, respectively.

  15. An adaptive finite element method for high speed flows

    Science.gov (United States)

    Peraire, J.; Morgan, K.; Peiro, J.; Zienkiewicz, O. C.

    1987-01-01

    The solution of the equations of compressible high speed flow, on unstructured triangular grids in 2D and tetrahedral grids in 3D, is considered. Solution methods based upon both Taylor-Galerkin and Runge-Kutta time-stepping techniques are presented and the incorporation of the ideas of flux corrected transport (FCT) is discussed. These methods are combined with an adaptive mesh regeneration procedure and are employed in the solution of several examples, consisting of Euler flows in both 2D and 3D and Navier-Stokes flows in 2D.

  16. Organic Solar Cells Based on a 2D Benzo[1,2-b:4,5-b']difuran-Conjugated Polymer with High-Power Conversion Efficiency.

    Science.gov (United States)

    Huo, Lijun; Liu, Tao; Fan, Bingbing; Zhao, Zhiyuan; Sun, Xiaobo; Wei, Donghui; Yu, Mingming; Liu, Yunqi; Sun, Yanming

    2015-11-18

    A novel 2D benzodifuran (BDF)-based copolymer (PBDF-T1) is synthesized. Polymer solar cells fabricated with PBDF-T1 show high power conversion efficiency of 9.43% and fill factor of 77.4%, which is higher than the performance of its benzothiophene (BDT) counterpart (PBDT-T1). These results provide important progress for BDF-based copolymers and demonstrate that BDF-based copolymers can be competitive with the well-studied BDT counterparts via molecular structure design and device optimization. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Determinación de la carga topológica de un haz bessel-gauss mediante el patrón de difracción a través de una abertura triangular equilátera

    Directory of Open Access Journals (Sweden)

    Cristian Hernando Acevedo

    2015-01-01

    Full Text Available La carga topológica de una onda electromagnética CT, está relacionada con su distribucion espacial en el frente de onda. Ondas electromagnéticas con un factor acimutal exp(il en su fase, tienen CT entera (l=m o no entera (l=M. Estas ondas electromagnéticas con un valor definido de carga topológica pueden ser producidas en el régimen visible utilizando máscaras tenedor holográficas generadas por computador. En este artículo se estudia mediante simulaciones numéricas la red triangular formada en el régimen de intensidad de Fraunhofer de haces Bessel-Gauss con CT entera y no entera que han difractado sobre una rendija en forma triangular para determinar su signo y su magnitud. También se presentan los resultados experimentales de la intensidad en campo lejano obtenidos al difractar una onda luminosa Bessel-Gauss con CT entera y no entera a través de una rendija triangular equilátera. Argumentos cualitativos parciales han sido expuestos para explicar el fenómeno de difracción de estos haces con carga topológica. Aquí se presentan argumentos cualitativos y cuantitativos que permiten explicar todos los resultados de la difracción por una abertura triangular de haces con carga topológica obtenidos ya sea por simulación numérica o mediante su realización experimental.

  18. Effect of electron-electron interaction on cyclotron resonance in high-mobility InAs/AlSb quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Krishtopenko, S. S., E-mail: sergey.krishtopenko@mail.ru; Gavrilenko, V. I. [Institute for Physics of Microstructures, Russian Academy of Sciences, 603950 Nizhny Novgorod, GSP-105 (Russian Federation); Lobachevsky State University, 23 Prospekt Gagarina, 603950 Nizhny Novgorod (Russian Federation); Ikonnikov, A. V. [Institute for Physics of Microstructures, Russian Academy of Sciences, 603950 Nizhny Novgorod, GSP-105 (Russian Federation); Orlita, M. [Laboratoire National des Champs Magnétiques Intenses (LNCMI-G), CNRS, 25 rue des Martyrs, B.P. 166, 38042 Grenoble (France); Sadofyev, Yu. G. [P.N. Lebedev Physical Institute, Russian Academy of Sciences, Moscow 119991, GSP-1, 53 Leninskiy Prospect (Russian Federation); Goiran, M. [Laboratoire National des Champs Magnétiques Intenses (LNCMI-T), CNRS, 143 Avenue de Rangueil, 31400 Toulouse (France); Teppe, F.; Knap, W. [Laboratoire Charles Coulomb (L2C), UMR CNRS 5221, GIS-TERALAB, Universite Montpellier II, 34095 Montpellier (France)

    2015-03-21

    We report observation of electron-electron (e-e) interaction effect on cyclotron resonance (CR) in InAs/AlSb quantum well heterostructures. High mobility values allow us to observe strongly pronounced triple splitting of CR line at noninteger filling factors of Landau levels ν. At magnetic fields, corresponding to ν > 4, experimental values of CR energies are in good agreement with single-electron calculations on the basis of eight-band k ⋅ p Hamiltonian. In the range of filling factors 3 < ν < 4 pronounced, splitting of CR line, exceeding significantly the difference in single-electron CR energies, is discovered. The strength of the splitting increases when occupation of the partially filled Landau level tends to a half, being in qualitative agreement with previous prediction by MacDonald and Kallin [Phys. Rev. B 40, 5795 (1989)]. We demonstrate that such behaviour of CR modes can be quantitatively described if one takes into account both electron correlations and the mixing between conduction and valence bands in the calculations of matrix elements of e-e interaction.

  19. Study of stacked-emitter layer for high efficiency amorphous/crystalline silicon heterojunction solar cells

    Science.gov (United States)

    Lee, Youngseok; Kim, Heewon; Iftiquar, S. M.; Kim, Sunbo; Kim, Sangho; Ahn, Shihyun; Lee, Youn-Jung; Dao, Vinh Ai; Yi, Junsin

    2014-12-01

    A modified emitter, of stacked two layer structure, was investigated for high-efficiency amorphous/crystalline silicon heterojunction (HJ) solar cells. Surface area of the cells was 181.5 cm2. The emitter was designed to achieve a high open circuit voltage (Voc) and fill factor (FF). When doping of the emitter layer was increased, it was observed that the silicon dihydride related structural defects within the films increased, and the Voc of the HJ cell decreased. On the other hand, while the doping concentration of the emitter was reduced the FF of the cell reduced. Therefore, a combination of a high conductivity and low defects of a single emitter layer appears difficult to obtain, yet becomes necessary to improve the cell performance. So, we investigated a stacked-emitter with low-doped/high-doped double layer structure. A low-doped emitter with reduced defect density was deposited over the intrinsic hydrogenated amorphous silicon passivation layer, while the high-doped emitter with high conductivity was deposited over the low-doped emitter. The effects of doping and defect density of the emitter, on the device performance, were elucidated by using computer simulation and an optimized device structure was formulated. The simulation was performed with the help of Automat for the Simulation of Heterostructures simulation software. Finally, based on the simulation results, amorphous/crystalline heterojunction silicon solar cells were optimized by reducing density of defect states in the stacked-emitter structure and we obtained 725 mV, 77.41%, and 19.0% as the open-circuit voltage, fill factor, and photo-voltaic conversion efficiency of the device, respectively.

  20. Ultra-high cell-density silicon photomultipliers with high detection efficiency

    Science.gov (United States)

    Acerbi, Fabio; Gola, Alberto; Regazzoni, Veronica; Paternoster, Giovanni; Borghi, Giacomo; Piemonte, Claudio; Zorzi, Nicola

    2017-05-01

    Silicon photomultipliers (SiPMs) are arrays of many single-photon avalanche diodes (SPADs), all connected in parallel. Each SPAD is sensitive to single photons and the SiPM gives an output proportional to the number of detected photons. These sensors are becoming more and more popular in different applications, from high-energy physics to spectroscopy, and they have been significantly improved over last years, decreasing the noise, increasing the cell fill-factor (FF) and thus achieving very high photon-detection efficiency (PDE). In FBK (Trento, Italy), we developed new SiPM technologies with high-density (HD) and, more recently, ultra-high-density (UHD) of cells (i.e. density of SPADs). These technologies employ deep-trenches between cells, for electrical and optical isolation. As an extreme case the smallest-cell, SiPM, i.e. with 5μm cell pitch, has about 40000 SPADs per squared millimeter. Such small SPAD dimensions gives a significantly high dynamic range to the SiPM. These small-cells SiPM have a lower correlated noise (including lower afterpulsing probability) and a faster recharge time (in the order of few nanoseconds), and they also preserve a very good detection efficiency (despite the small SPAD dimension).

  1. Heterometallic Zn3Ln3Ensembles Containing (μ6-CO3) Ligand and Triangular Disposition of Ln3+ions: Analysis of Single-Molecule Toroic (SMT) and Single-Molecule Magnet (SMM) Behavior.

    Science.gov (United States)

    Goura, Joydeb; Colacio, Enrique; Herrera, Juan Manuel; Suturina, Elizaveta A; Kuprov, Ilya; Lan, Yanhua; Wernsdorfer, Wolfgang; Chandrasekhar, Vadapalli

    2017-11-21

    Two new heterometallic Zn 3 Ln 3 (Ln 3+ =Dy, Tb) complexes, with a double triangular topology of the metal ions, have been assembled from the polytopic Mannich base ligand 6,6'-{[2-(dimethylamino)ethylazanediyl]bis(methylene)}bis(2-methoxy-4-methylphenol) (H 2 L) with the aid of an in situ generated carbonate ligand from atmospheric CO 2 fixation. Theoretical calculations indicate axial ground states for the Ln 3+ ions in these complexes, with their local magnetic moments being almost coplanar and tangential to the Ln 3+ atoms that define the equilateral triangle. Therefore, they can be considered as single-molecule toroics (SMTs) with almost zero total magnetic moment. Micro-SQUID measurements on the Dy 3+ counterpart show hysteresis loops below 3 K that have an S-shape, with large coercive fields opening upon cooling. This behavior is typical of a single molecule magnet (SMM) with very slow zero-field relaxation. At around ±0.35 T, the loops have a broad step, which is due to a direct relaxation process and corresponds to an acceleration of the relaxation of the magnetization, also observed at this magnetic field from ac susceptibility measurements. Simulations suggest that the broad step corresponds to two level avoidance of crossing points where the spin chiral Kramers doublet meets excited states of the coupled manifold, whose position is defined by exchange and dipole interactions. The Tb 3+ counterpart does not exhibit SMM behavior, which is due to the fact that the degeneracy of the ground state of the exchange coupled system is lifted at zero field, thus favoring quantum tunneling of magnetization (QTM). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Estudio del proceso de ebullicion en el interior de un tubo multipuerto extruido en aluminio con mini-canales de geometria triangular usando R32 y R134a como fluidos de trabajo

    Science.gov (United States)

    Ramirez Rivera, Francisco Alberto

    The use of multiport mini-channel tubes in compact exchangers has increased in the last few years. They contributing to improve thermal efficient, compactness, energy conservation and required lower refrigerants charge by which reduction of greenhouse gases emission. Those mentioned advantages are very important aspects with regard to modern refrigeration systems design. For that reason, several experimental investigation have been carried out in order to characterize the flow boiling heat transfer process and frictional pressure drop in tubes with parallel channels. Since, the ability to estimate pressure drop and heat transfer coefficient for specific conditions is a fundamental issue to optimise the design of compact heat exchanger. In this study, the characteristics of two- phase flow pressure drop and convective boiling heat transfer have been investigated experimentally inside multiport mini-channel aluminium tube with triangular geometry, hydraulic diameter 0.715 mm and heating length of 1205 mm using R32 and R134a as working fluids. A wide experimental campaign has been carried out to complete an array of measurement under different conditions for both refrigerants studied. The experimental conditions examined included: mass velocity 275-1230 kgm -2s-1, heat flux 0.75-9.30 kWm-2, saturation temperature, 5°C, 7.5°C, 12.5°C, vapour quality 0.012-0.51. The database presented consists of 312 averages values, 223 averages values were recorded for R134a and 89 for R32. The flow boiling averages values were calculated selecting a sample of 40 readings (steps 20s) in stable conditions for all measured variables at each mass velocity tested.

  3. Towards the Hall viscosity of the Fermi-liquid-like phase at the filling factor of 1/2

    Science.gov (United States)

    Milovanović, M. V.

    2010-12-01

    We discuss the Berry curvature calculations of the Hall viscosity for the Fermi-liquid-like state, i.e., a Fermi-liquid state of underlying composite particles of the Hall system. We conclude, within assumptions made, that in the linear response, with small deformation of the system and in the thermodynamic limit, the Hall viscosity takes the value characteristic for the Laughlin states. We present arguments that the value is the same even for general deformations in the same limit.

  4. High performance organic photovoltaics with zinc oxide and graphene oxide buffer layers

    Science.gov (United States)

    Mohd Yusoff, Abd Rashid Bin; Kim, Hyeong Pil; Jang, Jin

    2014-01-01

    We report air stable inverted organic photovoltaics (OPVs) incorporating graphene oxide (GO) and solution processed zinc oxide (ZnO) as hole transport and electron transport layers, respectively. Both the hole transport layer and the electron transport layer (HTL and ETL) are of advantage in high transparency and environmental stability. The use of GO and ZnO in poly(2,7-carbazole) derivative (PCDTBT):fullerene derivative (PC70BM)-based inverted OPVs leads to an improved device stability and enhanced high open circuit voltage (Voc) of 0.81 V, a short-circuit current density (Jsc) of 14.10 mA cm-2, and a fill factor (FF) of 54.44 along with a power conversion efficiency of 6.20%.

  5. An Improved Triangular Element With Drilling Rotations

    DEFF Research Database (Denmark)

    Damkilde, Lars; Grønne, Mikael

    2002-01-01

    by rotations in the corner nodes. Compared to Allman's plane element which was the first succesfull implementation of drilling rotations the proposed element has extra displacements in the mid-side nodes parallel to the element sides. The performance should therefore be better and closer to the LST...

  6. Graphene Plasmons in Triangular Wedges and Grooves

    DEFF Research Database (Denmark)

    Gonçalves, P. A. D.; Dias, E. J. C.; Xiao, Sanshui

    2016-01-01

    and tunability of graphene plasmons guided along the apex of a graphene-covered dielectric wedge or groove. In particular, we present a quasi-analytic model to describe the plasmonic eigenmodes in such a system, including the complete determination of their spectrum and corresponding induced potential...... and electric-field distributions. We have found that the dispersion of wedge/groove graphene plasmons follows the same functional dependence as their flat-graphene plasmon counterparts, but now scaled by a (purely) geometric factor in which all the information about the system’s geometry is contained. We...

  7. Graphene Plasmons in Triangular Wedges and Grooves

    DEFF Research Database (Denmark)

    Gonçalves, P. A. D.; Dias, E. J. C.; Xiao, Sanshui

    2016-01-01

    The ability to effectively guide electromagnetic radiation below the diffraction limit is of the utmost importance in the prospect of all-optical plasmonic circuitry. Here, we propose an alternative solution to conventional metal-based plasmonics by exploiting the deep subwavelength confinement...

  8. Triangular Clinics: The Way of The Future

    OpenAIRE

    Seyed-Moayed Alavian

    2005-01-01

    Hepatitis C is not just a blood-borne disease, but a global threat, socially andeconomically. Every year, thousands of articles are written on this subject emphasizing the importance of urgent global efforts in reducing its incidence. World Health Organization (WHO) estimations suggest that up to 3% of the world's population (170 million) have been infected with HCV(1). About 85 percent of people with acute hepatitis C develop a chronic infection, an insidious disease whose barely discernible...

  9. Low-Pressure-Assisted Coating Method To Improve Interface between PEDOT:PSS and Silicon Nanotips for High-Efficiency Organic/Inorganic Hybrid Solar Cells via Solution Process.

    Science.gov (United States)

    Subramani, Thiyagu; Syu, Hong-Jhang; Liu, Chien-Ting; Hsueh, Chen-Chih; Yang, Song-Ting; Lin, Ching-Fuh

    2016-01-27

    Nanostructured silicon hybrid solar cells are promising candidates for a new generation photovoltaics because of their light-trapping abilities and solution processes. However, the performance of hybrid organic/Si nanostructure solar cells is hindered because of carrier recombination at surface and poor coverage of organic material poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) ( PSS) on nanostructures. Here we demonstrate low-pressure-assisted coating method of PSS on surface-modified silicon nanotips with broadband light-trapping characteristics to improve interface property and to achieve high-efficiency hybrid solar cells through a solution process. The approach enhances the effective minority-carrier lifetime and the coverage of PSS on the surface of nanostructures. Hybrid solar cells fabricated with surface-modified nanotips exhibit a high fill factor of 70.94%, short-circuit current density of 35.36 mA/cm(2), open-circuit voltage of 0.528 V, and power conversion efficiency of 13.36%. The high efficiency and the high fill factor are achieved because of conformal coating of PSS via a low-pressure-assisted coating process, excellent light harvesting without sacrificing the minority-carrier lifetime, and efficient charge separation/collection of photogenerated carriers.

  10. High-performance semitransparent perovskite solar cells with solution-processed silver nanowires as top electrodes.

    Science.gov (United States)

    Guo, Fei; Azimi, Hamed; Hou, Yi; Przybilla, Thomas; Hu, Mengyao; Bronnbauer, Carina; Langner, Stefan; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J

    2015-02-07

    In this work, we report efficient semitransparent perovskite solar cells using solution-processed silver nanowires (AgNWs) as top electrodes. A thin layer of zinc oxide nanoparticles is introduced beneath the AgNWs, which fulfills two essential functionalities: it ensures ohmic contact between the PC60BM and the AgNWs and it serves as a physical foundation that enables the solution-deposition of AgNWs without causing damage to the underlying perovskite. The as-fabricated semitransparent perovskite cells show a high fill factor of 66.8%, Voc = 0.964 V, Jsc = 13.18 mA cm(-2), yielding an overall efficiency of 8.49% which corresponds to 80% of the reference devices with reflective opaque electrodes.

  11. Towards an optimum silicon heterojunction solar cell configuration for high temperature and high light intensity environment

    KAUST Repository

    Abdallah, Amir

    2017-09-22

    We report on the performance of Silicon Heterojunction (SHJ) solar cell under high operating temperature and varying irradiance conditions typical to desert environment. In order to define the best solar cell configuration that resist high operating temperature conditions, two different intrinsic passivation layers were tested, namely, an intrinsic amorphous silicon a-SiO:H with CO/SiH ratio of 0.4 and a-SiOx:H with CO/SiH ratio of 0.8, and the obtained performance were compared with those of a standard SHJ cell configuration having a-Si:H passivation layer. Our results showed how the short circuit current density J, and fill factor FF temperature-dependency are impacted by the cell\\'s configuration. While the short circuit current density J for cells with a-SiO:H layers was found to improve as compared with that of standard a-Si:H layer, introducing the intrinsic amorphous silicon oxide (a-SiO:H) layer with CO/SiH ratio of 0.8 has resulted in a reduction of the FF at room temperature due to hindering the carrier transport by the band structure. Besides, this FF was found to improve as the temperature increases from 15 to 45°C, thus, a positive FF temperature coefficient.

  12. Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at $\\sqrt{s_{NN}}$=2.76 TeV

    CERN Document Server

    Abelev, Betty; Adamova, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan; Aglieri Rinella, Gianluca; Agocs, Andras Gabor; Agostinelli, Andrea; Aguilar Salazar, Saul; Ahammed, Zubayer; Ahmad, Arshad; Ahmad, Nazeer; Ahn, Sang Un; Akindinov, Alexander; Aleksandrov, Dmitry; Alessandro, Bruno; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Almaraz Avina, Erick Jonathan; Alme, Johan; Alt, Torsten; Altini, Valerio; Altinpinar, Sedat; Altsybeev, Igor; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshauser, Harald; Arbor, Nicolas; Arcelli, Silvia; Armesto, Nestor; Arnaldi, Roberta; Aronsson, Tomas Robert; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Aysto, Juha Heikki; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bailhache, Raphaelle Marie; Bala, Renu; Baldini Ferroli, Rinaldo; Baldisseri, Alberto; Baldit, Alain; Baltasar Dos Santos Pedrosa, Fernando; Ban, Jaroslav; Baral, Rama Chandra; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Barret, Valerie; Bartke, Jerzy Gustaw; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batyunya, Boris; Baumann, Christoph Heinrich; Bearden, Ian Gardner; Beck, Hans; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bellwied, Rene; Belmont-Moreno, Ernesto; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bergognon, Anais Annick Erica; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhati, Ashok Kumar; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Bjelogrlic, Sandro; Blanco, F; Blanco, Francesco; Blau, Dmitry; Blume, Christoph; Bock, Nicolas; Boettger, Stefan; Bogdanov, Alexey; Boggild, Hans; Bogolyubsky, Mikhail; Boldizsar, Laszlo; Bombara, Marek; Book, Julian; Borel, Herve; Borissov, Alexander; Bose, Suvendu Nath; Bossu, Francesco; Botje, Michiel; Boyer, Bruno Alexandre; Braidot, Ermes; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Browning, Tyler Allen; Broz, Michal; Brun, Rene; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Bugaiev, Kyrylo; Busch, Oliver; Buthelezi, Edith Zinhle; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calvo Villar, Ernesto; Camerini, Paolo; Canoa Roman, Veronica; Cara Romeo, Giovanni; Carena, Francesco; Carena, Wisla; Carminati, Federico; Casanova Diaz, Amaya Ofelia; Castillo Castellanos, Javier Ernesto; Casula, Ester Anna Rita; Catanescu, Vasile; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Charvet, Jean-Luc Fernand; Chattopadhyay, Sukalyan; Chattopadhyay, Subhasis; Chawla, Isha; Cherney, Michael Gerard; Cheshkov, Cvetan; Cheynis, Brigitte; Chiavassa, Emilio; Chibante Barroso, Vasco Miguel; Chinellato, David; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Coccetti, Fabrizio; Colamaria, Fabio; Colella, Domenico; Conesa Balbastre, Gustavo; Conesa del Valle, Zaida; Constantin, Paul; Contin, Giacomo; Contreras, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Cotallo, Manuel Enrique; Crochet, Philippe; Cruz Alaniz, Emilia; Cuautle, Eleazar; Cunqueiro, Leticia; D'Erasmo, Ginevra; Dainese, Andrea; Dalsgaard, Hans Hjersing; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Kushal; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; de Barros, Gabriel; De Caro, Annalisa; de Cataldo, Giacinto; de Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; de Rooij, Raoul Stefan; Delagrange, Hugues; Deloff, Andrzej; Demanov, Vyacheslav; Denes, Ervin; Deppman, Airton; Di Bari, Domenico; Di Giglio, Carmelo; Di Liberto, Sergio; Di Mauro, Antonio; Di Nezza, Pasquale; Diaz Corchero, Miguel Angel; Dietel, Thomas; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Dominguez, Isabel; Donigus, Benjamin; Dordic, Olja; Driga, Olga; Dubey, Anand Kumar; Ducroux, Laurent; Dupieux, Pascal; Dutta Majumdar, AK; Dutta Majumdar, Mihir Ranjan; Elia, Domenico; Emschermann, David Philip; Engel, Heiko; Erdal, Hege Austrheim; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Evans, David; Eyyubova, Gyulnara; Fabris, Daniela; Faivre, Julien; Falchieri, Davide; Fantoni, Alessandra; Fasel, Markus; Fearick, Roger Worsley; Fedunov, Anatoly; Fehlker, Dominik; Feldkamp, Linus; Felea, Daniel; Fenton-Olsen, Bo; Feofilov, Grigory; Fernandez Tellez, Arturo; Ferretti, Alessandro; Ferretti, Roberta; Figiel, Jan; Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Fusco Girard, Mario; Gaardhoje, Jens Joergen; Gagliardi, Martino; Gago, Alberto; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Garabatos, Jose; Garcia-Solis, Edmundo; Garishvili, Irakli; Gerhard, Jochen; Germain, Marie; Geuna, Claudio; Gheata, Andrei George; Gheata, Mihaela; Ghidini, Bruno; Ghosh, Premomoy; Gianotti, Paola; Girard, Martin Robert; Giubellino, Paolo; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez, Ramon; Gonschior, Alexey; Gonzalez Ferreiro, Elena; Gonzalez-Trueba, Laura Helena; Gonzalez-Zamora, Pedro; Gorbunov, Sergey; Goswami, Ankita; Gotovac, Sven; Grabski, Varlen; Graczykowski, Lukasz Kamil; Grajcarek, Robert; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoriev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grinyov, Boris; Grion, Nevio; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerra Gutierrez, Cesar; Guerzoni, Barbara; Guilbaud, Maxime Rene Joseph; Gulbrandsen, Kristjan Herlache; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Gutbrod, Hans; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hanratty, Luke David; Hansen, Alexander; Harmanova, Zuzana; Harris, John William; Hartig, Matthias; Hasegan, Dumitru; Hatzifotiadou, Despoina; Hayrapetyan, Arsen; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Herrmann, Norbert; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hicks, Bernard; Hille, Per Thomas; Hippolyte, Boris; Horaguchi, Takuma; Hori, Yasuto; Hristov, Peter Zahariev; Hrivnacova, Ivana; Huang, Meidana; Humanic, Thomas; Hwang, Dae Sung; Ichou, Raphaelle; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Incani, Elisa; Innocenti, Gian Michele; Ippolitov, Mikhail; Irfan, Muhammad; Ivan, Cristian George; Ivanov, Andrey; Ivanov, Marian; Ivanov, Vladimir; Ivanytskyi, Oleksii; Jacholkowski, Adam Wlodzimierz; Jacobs, Peter; Jangal, Swensy Gwladys; Janik, Malgorzata Anna; Janik, Rudolf; Jayarathna, Sandun; Jena, Satyajit; Jha, Deeptanshu Manu; Jimenez Bustamante, Raul Tonatiuh; Jirden, Lennart; Jones, Peter Graham; Jung, Hyung Taik; Jusko, Anton; Kakoyan, Vanik; Kalcher, Sebastian; Kalinak, Peter; Kalliokoski, Tuomo Esa Aukusti; Kalweit, Alexander Philipp; Kanaki, Kalliopi; Kang, Ju Hwan; Kaplin, Vladimir; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kazantsev, Andrey; Kebschull, Udo Wolfgang; Keidel, Ralf; Khan, Mohisin Mohammed; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Beomkyu; Kim, Dong Jo; Kim, Do Won; Kim, Jonghyun; Kim, Jin Sook; Kim, Minwoo; Kim, Mimae; Kim, Se Yong; Kim, Seon Hee; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Klay, Jennifer Lynn; Klein, Jochen; Klein-Bosing, Christian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Koch, Kathrin; Kohler, Markus; Kolojvari, Anatoly; Kondratiev, Valery; Kondratyeva, Natalia; Konevskih, Artem; Korneev, Andrey; Kour, Ravjeet; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kramer, Frederick; Kraus, Ingrid Christine; Krawutschke, Tobias; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Krus, Miroslav; Kryshen, Evgeny; Krzewicki, Mikolaj; Kucheriaev, Yury; Kuhn, Christian Claude; Kuijer, Paul; Kulakov, Igor; Kurashvili, Podist; Kurepin, A; Kurepin, AB; Kuryakin, Alexey; Kushpil, Svetlana; Kushpil, Vasily; Kweon, Min Jung; Kwon, Youngil; La Pointe, Sarah Louise; La Rocca, Paola; Ladron de Guevara, Pedro; Lakomov, Igor; Langoy, Rune; Lara, Camilo Ernesto; Lardeux, Antoine Xavier; Lazzeroni, Cristina; Le Bornec, Yves; Lea, Ramona; Lechman, Mateusz; Lee, Graham Richard; Lee, Ki Sang; Lee, Sung Chul; Lefevre, Frederic; Lehnert, Joerg Walter; Leistam, Lars; Lemmon, Roy Crawford; Lenhardt, Matthieu Laurent; Lenti, Vito; Leon Monzon, Ildefonso; Leon Vargas, Hermes; Leoncino, Marco; Levai, Peter; Lien, Jorgen; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Liu, Lijiao; Loenne, Per-Ivar; Loggins, Vera; Loginov, Vitaly; Lohn, Stefan Bernhard; Lohner, Daniel; Loizides, Constantinos; Loo, Kai Krister; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lovhoiden, Gunnar; Lu, Xianguo; Luettig, Philipp; Lunardon, Marcello; Luo, Jiebin; Luparello, Grazia; Luquin, Lionel; Luzzi, Cinzia; Ma, Rongrong; Maevskaya, Alla; Mager, Magnus; Mahapatra, Durga Prasad; Maire, Antonin; Mal'Kevich, Dmitry; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Ludmila; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Manko, Vladislav; Manso, Franck; Manzari, Vito; Mao, Yaxian; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Marin, Ana Maria; Marin Tobon, Cesar Augusto; Markert, Christina; Martashvili, Irakli; Martinengo, Paolo; Martinez, Mario Ivan; Martinez Davalos, Arnulfo; Martinez Garcia, Gines; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Mastromarco, Mario; Mastroserio, Annalisa; Matthews, Zoe Louise; Matyja, Adam Tomasz; Mayani, Daniel; Mayer, Christoph; Mazer, Joel; Mazzoni, Alessandra Maria; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Mercado Perez, Jorge; Meres, Michal; Miake, Yasuo; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz; Mitu, Ciprian Mihai; Mlynarz, Jocelyn; Mohanty, Ajit Kumar; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Monteno, Marco; Montes, Esther; Moon, Taebong; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Munhoz, Marcelo; Musa, Luciano; Musso, Alfredo; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Nattrass, Christine; Naumov, Nikolay; Navin, Sparsh; Nayak, Tapan Kumar; Nazarenko, Sergey; Nazarov, Gleb; Nedosekin, Alexander; Nicassio, Maria; Niculescu, Mihai; Nielsen, Borge Svane; Niida, Takafumi; Nikolaev, Sergey; Nikolic, Vedran; Nikulin, Sergey; Nikulin, Vladimir; Nilsen, Bjorn Steven; Nilsson, Mads Stormo; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Novitzky, Norbert; Nyanin, Alexandre; Nyatha, Anitha; Nygaard, Casper; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Oleniacz, Janusz; Oppedisano, Chiara; Ortona, Giacomo; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Pachmayer, Yvonne Chiara; Pachr, Milos; Padilla, Fatima; Pagano, Paola; Paic, Guy; Painke, Florian; Pajares, Carlos; Pal, S; Pal, Susanta Kumar; Palaha, Arvinder Singh; Palmeri, Armando; Papikyan, Vardanush; Pappalardo, Giuseppe; Park, Woo Jin; Passfeld, Annika; Patalakha, Dmitri Ivanovich; Paticchio, Vincenzo; Pavlinov, Alexei; Pawlak, Tomasz Jan; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitri; Perez Lara, Carlos Eugenio; Perez Lezama, Edgar; Perini, Diego; Perrino, Davide; Peryt, Wiktor Stanislaw; Pesci, Alessandro; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petran, Michal; Petris, Mariana; Petrov, Plamen Rumenov; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Piccotti, Anna; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Pitz, Nora; Piuz, Francois; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polichtchouk, Boris; Pop, Amalia; Porteboeuf-Houssais, Sarah; Pospisil, Vladimir; Potukuchi, Baba; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puchagin, Sergey; Puddu, Giovanna; Pujahari, Prabhat Ranjan; Pujol Teixido, Jordi; Pulvirenti, Alberto; Punin, Valery; Putis, Marian; Putschke, Jorn Henning; Quercigh, Emanuele; Qvigstad, Henrik; Rachevski, Alexandre; Rademakers, Alphonse; Radomski, Sylwester; Raiha, Tomi Samuli; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Ramirez Reyes, Abdiel; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Reichelt, Patrick; Reicher, Martijn; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riccati, Lodovico; Ricci, Renato Angelo; Richert, Tuva; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Rodrigues Fernandes Rabacal, Bartolomeu; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roed, Ketil; Rohr, David; Rohrich, Dieter; Romita, Rosa; Ronchetti, Federico; Rosnet, Philippe; Rossegger, Stefan; Rossi, Andrea; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Rybicki, Andrzej; Sadovsky, Sergey; Safarik, Karel; Sahoo, Raghunath; Sahu, Pradip Kumar; Saini, Jogender; Sakaguchi, Hiroaki; Sakai, Shingo; Sakata, Dosatsu; Salgado, Carlos Albert; Salzwedel, Jai; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Sano, Satoshi; Santo, Rainer; Santoro, Romualdo; Sarkamo, Juho Jaako; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schreiner, Steffen; Schuchmann, Simone; Schukraft, Jurgen; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Patrick Aaron; Scott, Rebecca; Segato, Gianfranco; Selyuzhenkov, Ilya; Senyukov, Serhiy; Seo, Jeewon; Serci, Sergio; Serradilla, Eulogio; Sevcenco, Adrian; Shabetai, Alexandre; Shabratova, Galina; Shahoyan, Ruben; Sharma, Natasha; Sharma, Satish; Shigaki, Kenta; Shimomura, Maya; Shtejer, Katherin; Sibiriak, Yury; Siciliano, Melinda; Sicking, Eva; Siddhanta, Sabyasachi; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, catherine; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Skjerdal, Kyrre; Smakal, Radek; Smirnov, Nikolai; Snellings, Raimond; Sogaard, Carsten; Soltz, Ron Ariel; Son, Hyungsuk; Song, Jihye; Song, Myunggeun; Soos, Csaba; Soramel, Francesca; Sputowska, Iwona; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Stefanini, Giorgio; Steinbeck, Timm Morten; Steinpreis, Matthew; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Stolpovskiy, Mikhail; Strabykin, Kirill; Strmen, Peter; Suaide, Alexandre Alarcon do Passo; Subieta Vasquez, Martin Alfonso; Sugitate, Toru; Suire, Christophe Pierre; Sukhorukov, Mikhail; Sultanov, Rishat; Sumbera, Michal; Susa, Tatjana; Szanto de Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szostak, Artur Krzysztof; Szymanski, Maciej; Takahashi, Jun; Tapia Takaki, Daniel Jesus; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terrevoli, Cristina; Thader, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony; Toia, Alberica; Torii, Hisayuki; Tosello, Flavio; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ulery, Jason Glyndwr; Ullaland, Kjetil; Ulrich, Jochen; Uras, Antonio; Urban, Jozef; Urciuoli, Guido Marie; Usai, Gianluca; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; van der Kolk, Naomi; van Leeuwen, Marco; Vande Vyvre, Pierre; Vannucci, Luigi; Vargas, Aurora Diozcora; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vechernin, Vladimir; Veldhoen, Misha; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Vikhlyantsev, Oleg; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Viyogi, Yogendra; Vodopianov, Alexander; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; von Haller, Barthelemy; Vranic, Danilo; Øvrebekk, Gaute; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Vladimir; Wan, Renzhuo; Wang, Dong; Wang, Mengliang; Wang, Yifei; Wang, Yaping; Watanabe, Kengo; Weber, Michael; Wessels, Johannes; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Alexander; Wilk, Grzegorz Andrzej; Williams, Crispin; Windelband, Bernd Stefan; Xaplanteris Karampatsos, Leonidas; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Hongyan; Yang, Shiming; Yasnopolsky, Stanislav; Yi, JunGyu; Yin, Zhongbao; Yoo, In-Kwon; Yoon, Jongik; Yu, Weilin; Yuan, Xianbao; Yushmanov, Igor; Zach, Cenek; Zampolli, Chiara; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zaviyalov, Nikolai; Zbroszczyk, Hanna Paulina; Zelnicek, Pierre; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhou, Daicui; Zhou, Fengchu; Zhou, You; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zinovjev, Gennady; Zoccarato, Yannick Denis; Zynovyev, Mykhaylo; Zyzak, Maksym

    2013-02-12

    The elliptic, $v_2$, triangular, $v_3$, and quadrangular, $v_4$, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions, and (anti-)protons in Pb–Pb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV with the ALICE detector at the Large Hadron Collider. Results obtained with the event plane and four-particle cumulant methods are reported for the pseudo-rapidity range |$\\eta$|8 GeV/c. The small $p_T$ dependence of the difference between elliptic flow results obtained from the event plane and four-particle cumulant methods suggests a common origin of flow fluctuations up to $p_T$ =8 GeV/c. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least $p_T$ =8 GeV/c indicating that the particle type dependence persists out to high $p_T$.

  13. Processing technology for high efficiency silicon solar cells

    Science.gov (United States)

    Spitzer, M. B.; Keavney, C. J.

    1985-01-01

    Recent advances in silicon solar cell processing have led to attainment of conversion efficiency approaching 20%. The basic cell design is investigated and features of greatest importance to achievement of 20% efficiency are indicated. Experiments to separately optimize high efficiency design features in test structures are discussed. The integration of these features in a high efficiency cell is examined. Ion implantation has been used to achieve optimal concentrations of emitter dopant and junction depth. The optimization reflects the trade-off between high sheet conductivity, necessary for high fill factor, and heavy doping effects, which must be minimized for high open circuit voltage. A second important aspect of the design experiments is the development of a passivation process to minimize front surface recombination velocity. The manner in which a thin SiO2 layer may be used for this purpose is indicated without increasing reflection losses, if the antireflection coating is properly designed. Details are presented of processing intended to reduce recombination at the contact/Si interface. Data on cell performance (including CZ and ribbon) and analysis of loss mechanisms are also presented.

  14. GaN Nanowire Arrays for High-Output Nanogenerators

    KAUST Repository

    Huang, Chi-Te

    2010-04-07

    Three-fold symmetrically distributed GaN nanowire (NW) arrays have been epitaxially grown on GaN/sapphire substrates. The GaN NW possesses a triangular cross section enclosed by (0001), (2112), and (2112) planes, and the angle between the GaN NW and the substrate surface is ∼62°. The GaN NW arrays produce negative output voltage pulses when scanned by a conductive atomic force microscope in contact mode. The average of piezoelectric output voltage was about -20 mV, while 5-10% of the NWs had piezoelectric output voltages exceeding -(0.15-0.35) V. The GaN NW arrays are highly stable and highly tolerate to moisture in the atmosphere. The GaN NW arrays demonstrate an outstanding potential to be utilized for piezoelectric energy generation with a performance probably better than that of ZnO NWs. © 2010 American Chemical Society.

  15. High-efficiency nanostructured window GaAs solar cells.

    Science.gov (United States)

    Liang, Dong; Kang, Yangsen; Huo, Yijie; Chen, Yusi; Cui, Yi; Harris, James S

    2013-10-09

    Nanostructures have been widely used in solar cells due to their extraordinary optical properties. In most nanostructured cells, high short circuit current has been obtained due to enhanced light absorption. However, most of them suffer from lowered open circuit voltage and fill factor. One of the main challenges is formation of good junction and electrical contact. In particular, nanostructures in GaAs only have shown unsatisfactory performances (below 5% in energy conversion efficiency) which cannot match their ideal material properties and the record photovoltaic performances in industry. Here we demonstrate a completely new design for nanostructured solar cells that combines nanostructured window layer, metal mesa bar contact with small area, high quality planar junction. In this way, we not only keep the advanced optical properties of nanostructures such as broadband and wide angle antireflection, but also minimize its negative impact on electrical properties. High light absorption, efficient carrier collection, leakage elimination, and good lateral conductance can be simultaneously obtained. A nanostructured window cell using GaAs junction and AlGaAs nanocone window demonstrates 17% energy conversion efficiency and 0.982 V high open circuit voltage.

  16. Highly efficient inverted polymer solar cells based on a cross-linkable water-/alcohol-soluble conjugated polymer interlayer.

    Science.gov (United States)

    Zhang, Kai; Zhong, Chengmei; Liu, Shengjian; Mu, Cheng; Li, Zhengke; Yan, He; Huang, Fei; Cao, Yong

    2014-07-09

    A cross-linkable water/alcohol soluble conjugated polymer (WSCP) material poly[9,9-bis(6'-(N,N-diethylamino)propyl)-fluorene-alt-9,9-bis(3-ethyl(oxetane-3-ethyloxy)-hexyl) fluorene] (PFN-OX) was designed. The cross-linkable nature of PFN-OX is good for fabricating inverted polymer solar cells (PSCs) with well-defined interface and investigating the detailed working mechanism of high-efficiency inverted PSCs based on poly[4,8-bis(2-ethylhexyloxyl)benzo[1,2-b:4,5-b']dithio-phene-2,6-diyl-alt-ethylhexyl-3-fluorothithieno[3,4-b]thiophene-2-carboxylate-4,6-diyl] (PTB7) and (6,6)-phenyl-C71-butyric acid methyl ester (PC71BM) blend active layer. The detailed working mechanism of WSCP materials in high-efficiency PSCs were studied and can be summarized into the following three effects: a) PFN-OX tunes cathode work function to enhance open-circuit voltage (Voc); b) PFN-OX dopes PC71BM at interface to facilitate electron extraction; and c) PFN-OX extracts electrons and blocks holes to enhance fill factor (FF). On the basis of this understanding, the hole-blocking function of the PFN-OX interlayer was further improved with addition of a ZnO layer between ITO and PFN-OX, which led to inverted PSCs with a power conversion efficiency of 9.28% and fill factor high up to 74.4%.

  17. Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb–Pb collisions at √(s{sub NN})=2.76 TeV

    Energy Technology Data Exchange (ETDEWEB)

    Abelev, B. [Lawrence Livermore National Laboratory, Livermore, CA (United States); Adam, J. [Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague (Czech Republic); Adamová, D. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež u Prahy (Czech Republic); Adare, A.M. [Yale University, New Haven, CT (United States); Aggarwal, M.M. [Physics Department, Panjab University, Chandigarh (India); Aglieri Rinella, G. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Agocs, A.G. [KFKI Research Institute for Particle and Nuclear Physics, Hungarian Academy of Sciences, Budapest (Hungary); Agostinelli, A. [Dipartimento di Fisica dell' Università and Sezione INFN, Bologna (Italy); Aguilar Salazar, S. [Instituto de Física, Universidad Nacional Autónoma de México, Mexico City (Mexico); Ahammed, Z. [Variable Energy Cyclotron Centre, Kolkata (India); Ahmad Masoodi, A.; Ahmad, N. [Department of Physics, Aligarh Muslim University, Aligarh (India); Ahn, S.U. [Gangneung-Wonju National University, Gangneung (Korea, Republic of); Akindinov, A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Aleksandrov, D. [Russian Research Centre Kurchatov Institute, Moscow (Russian Federation); Alessandro, B. [Sezione INFN, Turin (Italy); Alfaro Molina, R. [Instituto de Física, Universidad Nacional Autónoma de México, Mexico City (Mexico); Alici, A. [Centro Fermi – Centro Studi e Ricerche e Museo Storico della Fisica “Enrico Fermi”, Rome (Italy); Alkin, A. [Bogolyubov Institute for Theoretical Physics, Kiev (Ukraine); and others

    2013-02-12

    The elliptic, v{sub 2}, triangular, v{sub 3}, and quadrangular, v{sub 4}, azimuthal anisotropic flow coefficients are measured for unidentified charged particles, pions, and (anti-)protons in Pb–Pb collisions at √(s{sub NN})=2.76 TeV with the ALICE detector at the Large Hadron Collider. Results obtained with the event plane and four-particle cumulant methods are reported for the pseudo-rapidity range |η|<0.8 at different collision centralities and as a function of transverse momentum, p{sub T}, out to p{sub T}=20 GeV/c. The observed non-zero elliptic and triangular flow depends only weakly on transverse momentum for p{sub T}>8 GeV/c. The small p{sub T} dependence of the difference between elliptic flow results obtained from the event plane and four-particle cumulant methods suggests a common origin of flow fluctuations up to p{sub T}=8 GeV/c. The magnitude of the (anti-)proton elliptic and triangular flow is larger than that of pions out to at least p{sub T}=8 GeV/c indicating that the particle type dependence persists out to high p{sub T}.

  18. Robust High-performance Dye-sensitized Solar Cells Based on Ionic Liquid-sulfolane Composite Electrolytes

    Science.gov (United States)

    Lau, Genevieve P. S.; Décoppet, Jean-David; Moehl, Thomas; Zakeeruddin, Shaik M.; Grätzel, Michael; Dyson, Paul J.

    2015-01-01

    Novel ionic liquid-sulfolane composite electrolytes based on the 1,2,3-triazolium family of ionic liquids were developed for dye-sensitized solar cells. The best performing device exhibited a short-circuit current density of 13.4 mA cm−2, an open-circuit voltage of 713 mV and a fill factor of 0.65, corresponding to an overall power conversion efficiency (PCE) of 6.3%. In addition, these devices are highly stable, retaining more than 95% of the initial device PCE after 1000 hours of light- and heat-stress. These composite electrolytes show great promise for industrial application as they allow for a 14.5% improvement in PCE, compared to the solvent-free eutectic ionic liquid electrolyte system, without compromising device stability. PMID:26670595

  19. A constrained Delaunay discretization method for adaptively meshing highly discontinuous geological media

    Science.gov (United States)

    Wang, Yang; Ma, Guowei; Ren, Feng; Li, Tuo

    2017-12-01

    A constrained Delaunay discretization method is developed to generate high-quality doubly adaptive meshes of highly discontinuous geological media. Complex features such as three-dimensional discrete fracture networks (DFNs), tunnels, shafts, slopes, boreholes, water curtains, and drainage systems are taken into account in the mesh generation. The constrained Delaunay triangulation method is used to create adaptive triangular elements on planar fractures. Persson's algorithm (Persson, 2005), based on an analogy between triangular elements and spring networks, is enriched to automatically discretize a planar fracture into mesh points with varying density and smooth-quality gradient. The triangulated planar fractures are treated as planar straight-line graphs (PSLGs) to construct piecewise-linear complex (PLC) for constrained Delaunay tetrahedralization. This guarantees the doubly adaptive characteristic of the resulted mesh: the mesh is adaptive not only along fractures but also in space. The quality of elements is compared with the results from an existing method. It is verified that the present method can generate smoother elements and a better distribution of element aspect ratios. Two numerical simulations are implemented to demonstrate that the present method can be applied to various simulations of complex geological media that contain a large number of discontinuities.

  20. Experimental Simulation of Methane Hydrate Extraction at High Pressure Conditions: Influence of the Sediment Bed

    Science.gov (United States)

    Agudo, J. R.; Park, J.; Luzi, G.; Williams, M.; Rauh, C.; Wierschem, A.; Delgado, A.

    2017-10-01

    Being a clean alternative to other fossil fuels, Methane Hydrate (MH) is currently considered as one of the most important potential sources for hydrocarbon fuels [1]. In addition, the high energy density of MH and its stability at higher temperatures as compared to LNG (Liquefied Natural Gas) makes MH a potential greener method for energy transportation. At the same time, the low thermodynamic stability of MH strongly questions the future exploitation of gas hydrate deposits, turning its extraction into a possible geohazard [2]. Fluctuations in pressure, temperature, salinity, degree of saturation or sediment bed properties may cause methane gas release from the water lattice. We experimentally study the influence of the sediment bed geometry during formation-dissociation of MH. For this purpose, MH is synthesized within regular substrates in a 93 cm3 high pressure vessel. The regular substrates are triangular and quadratic arrangements of identical glass spheres with a diameter of 2 and 5 mm, respectively. MH formation within regular substrate reduces the possibility of spontaneous nucleation to a unique geometrical configuration. This fact permits us to characterize the kinetics of MH formation-dissociation as a function of the sediment bed geometry. Preliminary experimental results reveal a strong dependence of MH formation on the geometry of the regular substrate. For instance, under the same pressure and temperature, the kinetics of MH production is found to change by a factor 3 solely depending on the substrate symmetry, i.e. triangular or quadratic.