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1
Aligia, A. A., e Liliana Arrachea. "Triplet superconductivity in quasi-one-dimensional systems". Physical Review B 60, n. 22 (1 dicembre 1999): 15332–38. http://dx.doi.org/10.1103/physrevb.60.15332.
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Ding, Hanqin, e Jun Zhang. "Superconductivity in a one-dimensional correlated quantum system". Modern Physics Letters B 30, n. 19 (20 luglio 2016): 1650231. http://dx.doi.org/10.1142/s0217984916502316.
Testo completoAbstract (sommario):
We construct a one-dimensional (1D) theoretical model to clarify the occurrence of superconductivity. The weak-coupling (WC) theory allows a determination of the phase diagram. The constrained hopping induces additional two-body and three-body interactions. At half-filling, the three-body interaction is responsible for the triplet superconducting (TS) correlation. Away from half-filling, the two-body interaction works, favoring the singlet superconducting (SS) correlation. The results are expected to provide an insignificant insight into the superconductivity mechanism.
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Vaccarella, C. D., R. D. Duncan e C. A. R. Sá de Melo. "Triplet superconductors: Josephson effect in quasi-one-dimensional systems". Physica C: Superconductivity 391, n. 1 (agosto 2003): 89–97. http://dx.doi.org/10.1016/s0921-4534(03)00872-4.
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Feldman, Jacob. "Regularity Vs Genericity in the Perception of Collinearity". Perception 25, n. 3 (marzo 1996): 335–42. http://dx.doi.org/10.1068/p250335.
Testo completoAbstract (sommario):
The perception of collinearity is investigated, with the focus on the minimal case of three dots. As suggested previously, from the standpoint of probabilistic inference, the observer must classify each dot triplet as having arisen either from a one-dimensional curvilinear process or from a two-dimensional patch. The normative distributions of triplets arising from these two classes are unavailable to the observer, and are in fact somewhat counterintuitive. Hence in order to classify triplets, the observer invents distributions for each of the two opposed types, ‘regular’ (collinear) triplets and ‘generic’ (ie not regular) triplets. The collinear prototype is centered at 0° (ie perfectly straight), whereas the generic prototype, contrary to the normative statistics, is centered at 120° away from straight—apparently because this is the point most distant in triplet space from straight and thus creates the maximum possible contrast between the two prototypes. By default, these two processes are assumed to be equiprobable in the environment. An experiment designed to investigate how subjects' judgments are affected by conspicuous environmental deviations from this assumption is reported. The results suggest that observers react by elevating or depressing the expected probability of the generic prototype relative to the regular one, leaving the prototype structure otherwise intact.
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Suginishi, Yuuichi, e Hiroshi Shimahara. "Spin-Triplet Superconductivity Mediated by Phonons in Quasi-One-Dimensional Systems". Journal of the Physical Society of Japan 73, n. 11 (novembre 2004): 3121–28. http://dx.doi.org/10.1143/jpsj.73.3121.
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Lee, I. J. "Coexistence of spin triplet superconductivity and antiferromagnetism in a quasi-one-dimensional system (TMTSF)2PF6". Journal of Magnetism and Magnetic Materials 310, n. 2 (marzo 2007): 657–59. http://dx.doi.org/10.1016/j.jmmm.2006.10.187.
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Dohnal, Michal, Tomáš Vogel, Martin Šanda e Vladimíra Jelínková. "Uncertainty Analysis of a Dual-Continuum Model Used to Simulate Subsurface Hillslope Runoff Involving Oxygen-18 as Natural Tracer". Journal of Hydrology and Hydromechanics 60, n. 3 (1 settembre 2012): 194–205. http://dx.doi.org/10.2478/v10098-012-0017-0.
Testo completoAbstract (sommario):
Uncertainty Analysis of a Dual-Continuum Model Used to Simulate Subsurface Hillslope Runoff Involving Oxygen-18 as Natural TracerA one-dimensional dual-continuum model (also known as dual-permeability model) was used to simulate the lateral component of subsurface runoff and variations in the natural18O content in hillslope discharge. Model predictions were analyzed using the GLUE generalized likelihood uncertainty estimation procedure. Model sensitivity was evaluated by varying two separate triplets of parameters. The first triplet consisted of key parameters determining the preferential flow regime, i.e., the volumetric proportion of the preferential flow domain, a first-order transfer coefficient characterizing soil water exchange between the two flow domains of the dual-continuum system, and the saturated hydraulic conductivity of the preferential flow domain. The second triplet involved parameters controlling exclusively the soil hydraulic properties of the preferential flow domain, i.e., its retention curve and hydraulic conductivity function. Results of the analysis suggest high sensitivity to all parameters of the first triplet, and large differences in sensitivity to the parameters of the second triplet. The sensitivity analysis also confirmed a significant improvement in the identifiability of preferential flow parameters when18O content was added to the objective function.
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SHARMA, MEENAKSHI, KAMLESH KUMARI e ISHWAR SINGH. "QUANTUM MONTE CARLO SIMULATION STUDY OF ONE-DIMENSIONAL PERIODIC ANDERSON MODEL". International Journal of Modern Physics B 13, n. 32 (30 dicembre 1999): 3927–42. http://dx.doi.org/10.1142/s0217979299004094.
Testo completoAbstract (sommario):
Many rare earth and actinide intermetallics, known as Heavy Fermion Systems, have recently been successfully described by the Periodic Anderson Model. We investigate, in this work, various electronic and magnetic properties of the one-dimensional Periodic Anderson model using path integral formulation along with the quantum Monte Carlo simulation technique. We have studied the singlet and triplet pairing correlation functions, nearest neighbor charge-density correlations, spin density correlations, local squared magnetic moment and probability of double occupancy of f-electrons, as a function of intra-atomic Coulomb interaction for various values of hybridization parameter and the temperatures.
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Kaneyuki, Soji, e Hiroshi Asano. "Graded Lie algebras and generalized Jordan triple systems". Nagoya Mathematical Journal 112 (dicembre 1988): 81–115. http://dx.doi.org/10.1017/s002776300000115x.
Testo completoAbstract (sommario):
One frequently encounters (real) semisimple graded Lie algebras in various branches of differential geometry (e.g. [16], [9], [14], [18]). It is therefore desirable to study semisimple graded Lie algebras, including those which have been studied individually, in a unified way. One of our concerns is to classify (finite-dimensional) semisimple graded Lie algebras in a way that enables us to construct them.
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CHELTSOV, V. F. "EXACT THEORY OF SPONTANEOUS EMISSION OF TWO LEVEL ATOM IN ONE-DIMENSIONAL CAVITY". Modern Physics Letters B 09, n. 14 (20 giugno 1995): 859–70. http://dx.doi.org/10.1142/s0217984995000814.
Testo completoAbstract (sommario):
The exact theory of the spontaneous emission of a motionless two level atom in a one-dimensional cavity at zero temperature is presented. In the damped cavity case, using the theory of quasistationary systems and a novel algorithm in operating casual ζ-functions, the theory predicts a hidden-triplet form of emission spectrum which turns abruptly to a singlet when the cavity passive linewidth Γ c /2 becoming equal to twice the coupling constant.
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Sankar, Karthika, Rahna Manoharan, Safna Saif e T. Priya Rose. "An optimum design of one dimensional photonic crystal for solar cell applications". IOP Conference Series: Materials Science and Engineering 1219, n. 1 (1 gennaio 2022): 012047. http://dx.doi.org/10.1088/1757-899x/1219/1/012047.
Testo completoAbstract (sommario):
Abstract Efficient anti reflection (AR) coatings and back reflectors are crucial components for the better performance of a solar cell. Hence perfect designing of the same is very important. We propose the design of both these structures based on a multilayer dielectric system, a one dimensional photonic crystal, with maximum efficiency on the basis of optical interference transfer matrix theory. Optical parameters were optimized and transmission and reflection spectra were obtained using transfer matrix formulation via a personal computer using MATLAB program. Theoretical analysis has shown that a triple layer AR coating and a DBR based back reflector effectively enhance the efficiency of a solar cell.
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Akashi, Muhammad, e Noam Soker. "Shaping planetary nebulae with jets in inclined triple stellar systems". Proceedings of the International Astronomical Union 12, S323 (ottobre 2016): 227–30. http://dx.doi.org/10.1017/s174392131700196x.
Testo completoAbstract (sommario):
AbstractWe conduct three-dimensional hydrodynamical simulations of two opposite jets launched obliquely to the orbital plane around an asymptotic giant branch (AGB) star and within its dense wind, and demonstrate the formation of a ‘messy’ planetary nebula (PN), namely, a PN lacking any type of symmetry (highly irregular). In building the initial conditions we assume that a tight binary system orbits the AGB star, and that the orbital plane of the tight binary system is inclined to the orbital plane of binary system and the AGB star. We further assume that the accreted mass onto the tight binary system forms an accretion disk around one of the stars, and that the plane of the disk is in between the two orbital planes. The highly asymmetrical lobes that we obtain support the notion that messy PNe might be shaped by triple stellar systems.
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DING, HANQIN, e JUN ZHANG. "EFFECT OF CORRELATED-HOPPING INTERACTION ON A ONE-DIMENSIONAL EXTENDED HUBBARD MODEL WITH SPIN-EXCHANGE INTERACTION". Modern Physics Letters B 26, n. 07 (20 marzo 2012): 1150044. http://dx.doi.org/10.1142/s0217984911500448.
Testo completoAbstract (sommario):
By using the field-theoretical techniques combining bosonization with renormalization group, we study a one-dimensional (1D) model of interacting electrons with on-site repulsion (U > 0), nearest-neighbor (nn) exchange (J) and correlated-hopping (t2, t3) interactions at weak coupling. In the case of a half-filled band, the two-body interaction t2 does not influence phase diagram of the model, while the presence of three-body interaction t3 makes the physics of the system highly non-trivial. By a Hartree–Fock decoupling, the effects of t3 bring about hopping of pairs, V-like (nn Coulomb interaction) and isotropic exchange terms in the reduced model Hamiltonian. Interestingly, a negative t3 provides a possibility for the occurrence of the triplet superconductivity in 1D system with purely repulsive interactions (U, J > 0). The ground state phase diagram including the insulating and superconducting phases is discussed analytically.
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Суханов, А. А., e В. А. Сабликов. "Спиновые состояния электронов в двойной квантовой точке в двумерном топологическом изоляторе со спин-орбитальным взаимодействием". Физика и техника полупроводников 53, n. 9 (2019): 1257. http://dx.doi.org/10.21883/ftp.2019.09.48134.17.
Testo completoAbstract (sommario):
AbstractThe spectra and spin structure of the states of two interacting electrons localized in a double quantum dot in a two-dimensional topological insulator with spin-orbit interaction are investigated. It is found that, in such a system, a singlet-triplet transition in the ground state without a magnetic field can be implemented. Spin-orbit interaction leads to the splitting of polarized triplet levels and to anticrossing, when one of them crosses the singlet.
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ARTÉS, JOAN C., ALEX C. REZENDE e REGILENE D. S. OLIVEIRA. "GLOBAL PHASE PORTRAITS OF QUADRATIC POLYNOMIAL DIFFERENTIAL SYSTEMS WITH A SEMI-ELEMENTAL TRIPLE NODE". International Journal of Bifurcation and Chaos 23, n. 08 (agosto 2013): 1350140. http://dx.doi.org/10.1142/s021812741350140x.
Testo completoAbstract (sommario):
Planar quadratic differential systems occur in many areas of applied mathematics. Although more than one thousand papers have been written on these systems, a complete understanding of this family is still missing. Classical problems, and in particular, Hilbert's 16th problem [Hilbert, 1900, 1902], are still open for this family. In this article, we make a global study of the family [Formula: see text] of all real quadratic polynomial differential systems which have a semi-elemental triple node (triple node with exactly one zero eigenvalue). This family modulo the action of the affine group and time homotheties is three-dimensional and we give its bifurcation diagram with respect to a normal form, in the three-dimensional real space of the parameters of this form. This bifurcation diagram yields 28 phase portraits for systems in [Formula: see text] counting phase portraits with and without limit cycles. Algebraic invariants are used to construct the bifurcation set. The phase portraits are represented on the Poincaré disk. The bifurcation set is not only algebraic due to the presence of a surface found numerically. All points in this surface correspond to connections of separatrices.
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Hu, Qingqing, e Xiaohong Zhang. "Three-Way Fuzzy Sets and Their Applications (III)". Axioms 12, n. 1 (3 gennaio 2023): 57. http://dx.doi.org/10.3390/axioms12010057.
Testo completoAbstract (sommario):
Three-way fuzzy inference is the theoretical basis of three-way fuzzy control. The proposed TCRI method is based on a Mamdani three-way fuzzy implication operator and uses one inference and simple composition operation. In order to effectively improve the TCRI method, this paper proposes a full implication triple I algorithm for three-way fuzzy inference and gives the triple I solution to the TFMP problem. The emphasis of our research is R0 and Go¨del triple I solution, which is related to three-way residual implication, as well as Zadeh’s and Mamdani’s triple I solution, which is based on three-way fuzzy implication operator. Then the three-way fuzzy controller is constructed by the proposed Zadeh’s and R0 triple I algorithm. Finally, the proposed triple I algorithm is applied to the three-way fuzzy control system, and its advantage is illustrated by the three-dimensional surface diagram of the control variable.
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AFTALION, A., e S. J. CHAPMAN. "Asymptotic analysis of the bifurcation diagram for symmetric one-dimensional solutions of the Ginzburg–Landau equations". European Journal of Applied Mathematics 10, n. 5 (ottobre 1999): 477–95. http://dx.doi.org/10.1017/s0956792599003915.
Testo completoAbstract (sommario):
The bifurcation of symmetric superconducting solutions from the normal solution is considered for the one-dimensional Ginzburg–Landau equations by the methods of formal asymptotics. The behaviour of the bifurcating branch depends upon the parameters d, the size of the superconducting slab, and κ, the Ginzburg–Landau parameter. It was found numerically by Aftalion & Troy [1] that there are three distinct regions of the (κ, d) plane, labelled S1, S2 and S3, in which there are at most one, two and three symmetric solutions of the Ginzburg–Landau system, respectively. The curve in the (κ, d) plane across which the bifurcation switches from being subcritical to supercritical is identified, which is the boundary between S2 and S1∪S3, and the bifurcation diagram is analysed in its vicinity. The triple point, corresponding to the point at which S1, S2 and S3 meet, is determined, and the bifurcation diagram and the boundaries of S1, S2 and S3 are analysed in its vicinity. The results provide formal evidence for the resolution of some of the conjectures of Aftalion & Troy [1].
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Huang, Feng, Zhifeng Wang, Jing Wu, Ying Shen e Liqiong Chen. "Residual Triplet Attention Network for Single-Image Super-Resolution". Electronics 10, n. 17 (27 agosto 2021): 2072. http://dx.doi.org/10.3390/electronics10172072.
Testo completoAbstract (sommario):
Single-image super-resolution (SISR) techniques have been developed rapidly with the remarkable progress of convolutional neural networks (CNNs). The previous CNNs-based SISR techniques mainly focus on the network design while ignoring the interactions and interdependencies between different dimensions of the features in the middle layers, consequently hindering the powerful learning ability of CNNs. In order to address this problem effectively, a residual triplet attention network (RTAN) for efficient interactions of the feature information is proposed. Specifically, we develop an innovative multiple-nested residual group (MNRG) structure to improve the learning ability for extracting the high-frequency information and train a deeper and more stable network. Furthermore, we present a novel lightweight residual triplet attention module (RTAM) to obtain the cross-dimensional attention weights of the features. The RTAM combines two cross-dimensional interaction blocks (CDIBs) and one spatial attention block (SAB) base on the residual module. Therefore, the RTAM is not only capable of capturing the cross-dimensional interactions and interdependencies of the features, but also utilizing the spatial information of the features. The simulation results and analysis show the superiority of the proposed RTAN over the state-of-the-art SISR networks in terms of both evaluation metrics and visual results.
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Artés, Joan C., Regilene D. S. Oliveira e Alex C. Rezende. "Topological Classification of Quadratic Polynomial Differential Systems with a Finite Semi-Elemental Triple Saddle". International Journal of Bifurcation and Chaos 26, n. 11 (ottobre 2016): 1650188. http://dx.doi.org/10.1142/s0218127416501881.
Testo completoAbstract (sommario):
The study of planar quadratic differential systems is very important not only because they appear in many areas of applied mathematics but due to their richness in structure, stability and questions concerning limit cycles, for example. Even though many papers have been written on this class of systems, a complete understanding of this family is still missing. Classical problems, and in particular Hilbert’s 16th problem [Hilbert, 1900, 1902], are still open for this family. In this article, we make a global study of the family [Formula: see text] of all real quadratic polynomial differential systems which have a finite semi-elemental triple saddle (triple saddle with exactly one zero eigenvalue). This family modulo the action of the affine group and time homotheties is three-dimensional and we give its bifurcation diagram with respect to a normal form, in the three-dimensional real space of the parameters of this normal form. This bifurcation diagram yields 27 phase portraits for systems in [Formula: see text] counting phase portraits with and without limit cycles. Algebraic invariants are used to construct the bifurcation set and we present the phase portraits on the Poincaré disk. The bifurcation set is not just algebraic due to the presence of a surface found numerically, whose points correspond to connections of separatrices.
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Tian, A. L., B. Li, M. T. Huang e Zhuang De Jiang. "Instantaneous Measurement of 3D Profiles by Projecting Coded Grating". Key Engineering Materials 295-296 (ottobre 2005): 495–500. http://dx.doi.org/10.4028/www.scientific.net/kem.295-296.495.
Testo completoAbstract (sommario):
A three-dimensional profile measurement system based on a projection coded grating technique is presented. The system uses a designing and decoding technique for grey coded gratings. The coded grating has black, white and grey stripes. The period triples a conventional grating. It greatly increases the height measuring range without any decrease in stripe separation. The shape of object can be obtained from only one grating image. The system is suitable for instantaneous measurement of moving objects including human face. The technique proposed permits rapid 3D measurement and no moving parts are involved in the system. The hardware is relatively simple. Special data processing software is developed. Results of a practical example confirm the effectiveness of the proposed method.
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MASSA, L., J. M. AUSTIN e T. L. JACKSON. "Triple-point shear layers in gaseous detonation waves". Journal of Fluid Mechanics 586 (14 agosto 2007): 205–48. http://dx.doi.org/10.1017/s0022112007007008.
Testo completoAbstract (sommario):
Recent experiments have shown intriguing regions of intense luminescence or ‘hotspots’ in the vicinity of triple-point shear layers in propagating gaseous detonation waves. Localized explosions have also been observed to develop in these fronts. These features were observed in higher effective activation energy mixtures, but not in lower effective activation energy mixtures. The increased lead shock oscillation through a cell cycle in higher activation energy mixtures may result in a significantly increased disparity in the induction time on either side of the triple-point shear layer, and thus an enhanced mixing between reacted and non-reacted streams supported by Kelvin–Helmholtz instability. The relation between the shear-layer instability and the mixture effective activation energy is analysed by carrying out a spatial linear stability study for three mixtures with different activation energies and injection conditions that correspond to the experimental conditions. The role of vortical structures associated with Kelvin–Helmholtz instability in the formation of localized ignition is investigated by performing two-dimensional Navier–Stokes simulations with detailed chemical kinetics and transport. In the low activation energy mixture, large-scale vortical structures are observed to occur downstream of the induction distance; these structures do not have a noticeable effect on the reaction. In higher effective activation energy mixtures, a thin transverse ignition front develops near the interface between the two gas streams and results in a combustion structure decoupled from the entrainment region. The decoupling leads to attenuation of the instability growth rate when compared to frozen calculations, and a reduced heat release in the high vorticity region. The analysis indicates the instability plays a modest role in ignition events for high activation energy mixtures. The formation of localized explosions observed in high activation energy systems is instead linked to the impossibility of a one-dimensional reactive combustion wave supported by the injection conditions. In the absence of curvature effects and stream-tube divergence, a system of shock waves is formed which spreads the ignition to the cold gas stream.
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BROHOLM, C. L. "SPIN CORRELATIONS IN MAGNETIZED HALDANE CHAINS". International Journal of Modern Physics B 16, n. 20n22 (30 agosto 2002): 3250. http://dx.doi.org/10.1142/s0217979202014085.
Testo completoAbstract (sommario):
Neutron scattering experiments have been carried out in high magnetic fields to understand the magnetized state of the uniform spin-1 antiferromagnetic chain. In zero field this system has a cooperative singlet ground state with a gap to a propagating triplet excitation. The quasi-one-dimensional uniform spin-1 antiferromagnets NENP (Ni(C2D8N2)2NO2CIO4) and NDMAP (Ni(C5D14N2)2N3PF6) were examined. NENP has an alternating g-tensor such that staggered magnetization is induced for arbitrarily small fields and there is no finite field phase transition. In the high field phase the lowest energy mode has a field dependent gap and an unusually small effective spin wave velocity. NDMAP has only one spin per unit cell and hence a uniform g-tensor. This system has a critical transition at a finite field. Surprisingly the high field phase has quasi-two-dimensional or three-dimensional long-range order depending on the direction of the applied field. In the paramagnetic high field phase immediately above the ordering transition of NDMAP, there are gapless magnetic excitations that are broader in Q than the higher energy gap mode. The data is compared to theoretical predictions of a gapless incommensurate phase above the critical field.
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Конев, В. В., В. А. Улитко, Д. Н. Ясинская, Ю. Д. Панов e А. С. Москвин. "Влияние локальных корреляций на переход "однородный изолятор-сверхпроводник" в доменных границах фазы зарядового порядка 2D-системы со смешанной валентностью". Физика твердого тела 60, n. 11 (2018): 2093. http://dx.doi.org/10.21883/ftt.2018.11.46644.01nn.
Testo completoAbstract (sommario):
Abstract —It is demonstrated in the (pseudo)spin S = 1 formalism that the structure of antiphase domain boundaries in the phase of charge ordering of a mixed-valence system of the Cu^1+, 2+, 3+ “triplet” type in cuprates on a two-dimensional square lattice depends to a considerable extent on on-site correlation parameter U . The results of computer modeling on large square lattices illustrate the change in the boundary structure (from a homogeneous monovalent nonconducting structure of the Cu^2+ type to a filamentary superconducting one) induced by a relatively small variation of positive U values.
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Gamsjäger, Ernst, Boris Gschöpf e Jiří Svoboda. "Influence of Finite Mobilities of Triple Junctions on the Grain Morphology and Kinetics of Grain Growth". Metals 10, n. 2 (27 gennaio 2020): 185. http://dx.doi.org/10.3390/met10020185.
Testo completoAbstract (sommario):
Grain boundary networks composed of equal microstructural elements were investigated in a recent paper. In this work a more complicated artificial grain topology consisting of one four-sided, two six-sided and one eight-sided grain is designed to further investigate the influence of grain boundary and triple junction mobilities on the kinetics of the system in more detail. Depending on the value of the equal mobility of all triple junctions, the initially square-shaped four-sided grain changes its shape to become more or less rectangular. This indicates that the grain morphology is influenced by the value of the mobility of the triple junctions. It is also demonstrated that a grain arrangement with low mobility triple junctions controlling the kinetics of grain growth enhances growth of the large eight-sided grains. In addition, grain growth is investigated for different values of mobilities of triple junctions and grain boundaries. A strong elongation of several grains is predicted by the modeling results for reduced mobilities of the microstructural grain boundary elements. The two-dimensional modeling results are compared to micrographs of a heat-treated titanium niobium microalloyed steel. This feature, namely the evolution of elongated grains, is observed in the micrograph due to the pinning effect of (Ti, Nb)C precipitates at elevated soaking temperatures of around 1100 °C. Furthermore, the experiments show that a broader distribution of the grain sizes occur at 1100 °C compared to soaking temperatures, where pinning due to precipitates plays a less prominent role. A widening of the distribution of the grain sizes for small triple junction mobilities is also predicted by the unit cell model.
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Omarova, Sabina M., Zaira N. Verdieva, Alibek B. Alkhasov, Uhumaali G. Magomedbekov, Patimat A. Arbukhanova e Nadinbeg N. Verdiev. "PHASE EQUILIBRIA IN SYSTEM (LiF)2 – (NaCl)2 – Na3FSO4". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, n. 10 (16 novembre 2017): 4. http://dx.doi.org/10.6060/tcct.20176010.5631.
Testo completoAbstract (sommario):
The liquidus surface of the quasi-triple system LiF–NaCl–Na3FSO4 was studied by a differential-thermal method of physicochemical analysis. As a result of the studies, the crystallization temperature (554 °C) and the composition of the three-component eutectic, which can be used as a heat accumulator in thermal energy storage devices, are determined. When designing plants based on renewable energy sources, it is necessary to provide storage tanks for the concentration of thermal energy, so that the stored heat energy can be used even in the period of absence of solar radiation. The most suitable for thermal accumulation are salt eutectic mixtures. Priority in this respect is research devoted to the development of compositions as possible with large values of the latent heat of the solid-liquid phase transition. The experiment was carried out on the synchronous thermal analysis unit STA 449 F3 Phoenix, the company Netzsch, designed to operate in the temperature range from room temperature to 1500 ° C in an atmosphere of inert gases (argon). All facet triangle (LiF)2 – (NaCl)2 – Na3FSO4: stable diagonal (LiF)2 – (NaCl)2 of the triple mutual system Li, Na // F, Cl and quasibinary systems: LiF–Na3FSO4; NaCl – Na3FSO4 is of the eutectic type, therefore it can be assumed that a triple eutectic is formed in the system. To determine the thermo physical characteristics of the eutectic composition, the experiment is planned in accordance with the general rules of the projection-thermographic method. The one-dimensional polythermal section AB located in the crystallization field of lithium fluoride, where A is 50% (LiF)2+ 50% Na3FSO4, B is 50% (LiF)2+ 50% (NaCl)2 was experientally studied. The study of the AB section reveals the direction to the triple eutectic, from the poles of lithium fluoride crystallization, i.e. the study of this section revealed a constant ratio of sodium chloride and sulfate-sodium fluoride in the triple eutectic. At the point showing a constant ratio of the two initial components in the eutectic, the thermal effects of the secondary and tertiary crystallizations are combined, and the primary crystallization is fixed at 657 °C. This composition is the starting point for the investigation of the next section. The content of lithium fluoride in the eutectic is determined by studying the polythermal section of lithium fluoride from the crystallization pole and passing through the projection Ē to the side of the triangle (NaCl)2 – Na3FSO4. As a result of the studies, the crystallization temperature and the concentration of the initial salts in the triple eutectic have been established. The detected eutectic composition (EΔ) crystallizes at 554 °C and contains eq. %: (LiF)2 – 26; (NaCl)2 – 23; Na3FSO4 – 51.Forcitation:Omarova S.M., Verdieva Z.N., Alkhasov A.B., Magomedbekov U.G., Arbukhanova P.A., Verdiev N.N. Phase equilibria in system (LiF)2 – (NaCl)2 – Na3FSO4. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 10. P. 4-8
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Baroch, D., J. C. Morales, I. Ribas, V. J. S. Béjar, S. Reffert, C. Cardona Guillén, A. Reiners et al. "The CARMENES search for exoplanets around M dwarfs". Astronomy & Astrophysics 653 (settembre 2021): A49. http://dx.doi.org/10.1051/0004-6361/202141031.
Testo completoAbstract (sommario):
Context. M dwarfs are ideal targets for the search of Earth-size planets in the habitable zone using the radial velocity method, and are attracting the attention of many ongoing surveys. One of the expected results of these surveys is that new multiple-star systems have also been found. This is the case also for the CARMENES survey, thanks to which nine new double-line spectroscopic binary systems have already been announced. Aims. Throughout the five years of the survey the accumulation of new observations has resulted in the detection of several new multiple-stellar systems with long periods and low radial-velocity amplitudes. Here we newly characterise the spectroscopic orbits and constrain the masses of eight systems and update the properties of a system that we had reported earlier. Methods. We derived the radial velocities of the stars using two-dimensional cross-correlation techniques and template matching. The measurements were modelled to determine the orbital parameters of the systems. We combined CARMENES spectroscopic observations with archival high-resolution spectra from other instruments to increase the time span of the observations and improve our analysis. When available, we also added archival photometric, astrometric, and adaptive optics imaging data to constrain the rotation periods and absolute masses of the components. Results. We determined the spectroscopic orbits of nine multiple systems, eight of which are presented for the first time. The sample is composed of five single-line binaries, two double-line binaries, and two triple-line spectroscopic triple systems. The companions of two of the single-line binaries, GJ 3626 and GJ 912, have minimum masses below the stellar boundary, and thus could be brown dwarfs. We found a new white dwarf in a close binary orbit around the M star GJ 207.1, located at a distance of 15.79 pc. From a global fit to radial velocities and astrometric measurements, we were able to determine the absolute masses of the components of GJ 282 C, which is one of the youngest systems with measured dynamical masses.
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HANAMURA, E., J. INOUE e F. YURA. "DRESSED EXCITONS IN MICROCAVITY". Journal of Nonlinear Optical Physics & Materials 04, n. 01 (gennaio 1995): 13–25. http://dx.doi.org/10.1142/s0218863595000033.
Testo completoAbstract (sommario):
After reviewing the important roles of excitons in nonlinear optical responses, we demonstrate mutual and quantum-mechanical control of radiation field and excitons on the same footing in a microcavity. First we introduce dressed excitons as bosons interacting coherently and reversibly with a radiation mode in the microcavity. Although the vacuum Rabi splitting of the dressed exciton is the same as that of dressed atom, the emission spectrum under strong pumping shows quartet structure different from the triplet of dressed atom. Secondly, the population dynamics of dressed excitons, i.e., one-dimensional polaritons in the mesoscopic system is solved and the dominant distribution on a single mode is demonstrated above the critical pumping.
28
Miesen, Franciscus W. A. M., Hans C. M. Baeten, Harm A. Langermans, Leo H. Koole e Henk A. Claessens. "Novel, intramolecular hydrogen-transfer and cyclo-addition photochemistry of cyclic 1,3-dienes". Canadian Journal of Chemistry 69, n. 10 (1 ottobre 1991): 1554–62. http://dx.doi.org/10.1139/v91-230.
Testo completoAbstract (sommario):
With use of one- and two-dimensional NMR spectroscopy and deuterium labelling, the photochemistry of 9-endo-hydroxy-9-exo-vinyl-bicyclo[4.2.1]nonadiene (1) and the 9-exo-(11-dimethylvinyl)- (2) and 9-exo-ethyl- (3) analogues has been studied. Irradiation of 1–3 gave novel 8-membered ring systems 4–6 by a light-induced rearrangement process, in which the hydroxyl proton is transferred on one side of the molecule toward one of the termini of the endocyclic diene. This rearrangement process thus involves a formal hydrogen transfer, during which either H+ or H• may be transferred to a reactive diene intermediate. Replacement of the hydroxyl proton by deuterium in 1–3, and 2H NMR of the corresponding photoproducts, confirmed that the hydrogen translocation occurs intramolecularly. Prolonged irradiation of 4 and 5 results in the formation of pyran products 10 and 11 by an intramolecular photocycloaddition of the triplet excited state of the α,β-unsaturated ketone to 1,3-cis,cis-cyclooctadiene, via a stabilized bisallylic biradical intermediate. Conformational studies of the structurally more rigid system 10, which is derived from 4, revealed that the hydroxyl proton was transferred on the endo side of the molecule. Key words: intramolecular hydrogen transfer, photochemistry of hydroxy-alkyl-bicyclononadienes, intramolecular photocycloaddition, conformational studies.
29
NAKATSUJI, S., e Y. MAENO. "FERROMAGNETIC AND STRUCTURAL INSTABILITIES IN Ca2-xSrxRuO4". International Journal of Modern Physics B 16, n. 20n22 (30 agosto 2002): 3273–78. http://dx.doi.org/10.1142/s0217979202014152.
Testo completoAbstract (sommario):
Ca 2 - x Sr x RuO 4 is a unique quasi-two-dimensional multi-band system that connects the Mott insulator Ca2RuO4 with the spin-triplet superconductor Sr2RuO4. The isovalent Sr substitution changes the crystal distortions and thus modifies the hybridization and degeneracy of t2g orbitals. Such effective change of electron correlation induces the Mott transition and rich evolution of itinerant magnetism. One of the striking features in this system is the appearance of ferromagnetic critical behavior in the metallic phase near a zero-temperature structural instability (x c ≈ 0.5). The low temperature susceptibility shows Curie-like diverging behavior, and the electronic specific heat (Ce) divided by temperature, Ce/T, enormously increases up to 250 mJ/mol-Ru at x = 0.5. Moreover, critical enhancement of Wilson ratio is attributable to a ferromagnetic instability developed near the structural instability.
30
YAŞAR, FATIH, e MEHMET DILAVER. "THE STUDY OF PHASE TRANSITION BY PERIODIC DISTRIBUTION OF BIMODAL BONDS IN 2D POTTS MODEL". International Journal of Modern Physics C 20, n. 02 (febbraio 2009): 223–36. http://dx.doi.org/10.1142/s012918310901356x.
Testo completoAbstract (sommario):
We have studied the influence of the distribution of bimodal bonds on the phase transition in two-dimensional 8-state Potts model by the recently proposed Wang–Landau (WL) and the Swendsen–Wang (SW) algorithm. All simulations and measurements are done for r = 0.5. Physical quantities such as energy density and specific heat are evaluated at all temperatures. We have also obtained the probability distributions of the energy in order to monitor the transitions. We have observed that some cases of the periodically arranged bond distributions show a single peak, and some cases show double or triple peaks in the specific heat. Besides, it seems that the appearing of these peaks in the specific heat relates to a blocking procedure for periodicity. When the number of interaction pairs between the bimodal bonds is increased on the lattice with the blocking procedure, one can observe a single peak, otherwise, one can observe a double or triple peaks in the specific heat. From the point of view of simulation methods, the WL algorithm also works efficiently in the simulation of the system for a periodically arranged bond distribution as well as the SW algorithm.
31
Bi, Q., e P. Yu. "Computation of Normal Forms of Differential Equations Associated with Non-Semisimple Zero Eigenvalues". International Journal of Bifurcation and Chaos 08, n. 12 (dicembre 1998): 2279–319. http://dx.doi.org/10.1142/s0218127498001868.
Testo completoAbstract (sommario):
This paper presents a method to compute the normal forms of differential equations whose Jacobian evaluated at an equilibrium includes a double zero or a triple zero eigenvalue. The method combines normal form theory with center manifold theory to deal with a general n-dimensional system. Explicit formulas are derived and symbolic computer programs have been developed using a symbolic computation language Maple. This enables one to easily compute normal forms and nonlinear transformations up to any order for a given specific problem. The programs can be conveniently executed on a main frame, workstation or a PC machine without any interaction. Mathematical and practical examples are presented to show the applicability of the method.
32
Kazakov, Alexey O., Efrosiniia Y. Karatetskaia, Alexander D. Kozlov e Klim A. Safonov. "On the classification of homoclinic attractors of three-dimensional flows". Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva 21, n. 4 (30 dicembre 2019): 443–59. http://dx.doi.org/10.15507/2079-6900.21.201904.443-459.
Testo completoAbstract (sommario):
For three-dimensional dynamical systems with continuous time (flows), a classification of strange homoclinic attractors containing an unique saddle equilibrium state is constructed. The structure and properties of such attractors are determined by the triple of eigenvalues of the equilibrium state. The method of a saddle charts is used for the classification of homoclinic attractors. The essence of this method is in the construction of an extended bifurcation diagram for a wide class of three-dimensional flows (whose linearization matrix is written in the Frobenius form). Regions corresponding to different configurations of eigenvalues are marked in this extended bifurcation diagram. In the space of parameters defining the linear part of the considered class of three-dimensional flows bifurcation surfaces bounding 7 regions are constructed. One region corresponds to the stability of the equilibrium states while other 6 regions correspond to various homoclinic attractors of the following types: Shilnikov attractor, 2 types of spiral figure-eight attractors, Lorenz- like attractor, saddle Shilnikov attractor and attractor of Lyubimov-Zaks-Rovella. The paper also discusses questions related to the pseudohyperbolicity of homoclinic attractors of three-dimensional flows. It is proved that only homoclinic attractors of two types can be pseudohyperbolic: Lorenz-like attractors containing a saddle equilibrium with a two-dimensional stable manifold whose saddle value is positive and saddle Shilnikov attractors containing a saddle equilibrium state with a two-dimensional unstable manifold.
33
Shi, Fuqian, Jiang Xu e Shouqian Sun. "Fuzzy Case-Based Reasoning in Product Style Acquisition Incorporating Valence-Arousal-Based Emotional Cellular Model". Journal of Applied Mathematics 2012 (2012): 1–16. http://dx.doi.org/10.1155/2012/385079.
Testo completoAbstract (sommario):
Emotional cellular (EC), proposed in our previous works, is a kind of semantic cell that contains kernel and shell and the kernel is formalized by a triple-L = <P,d,δ>, wherePdenotes a typical set of positive examples relative to word-L,dis a pseudodistance measure on emotional two-dimensional space: valence-arousal, andδis a probability density function on positive real number field. The basic idea of EC model is to assume that the neighborhood radius of each semantic concept is uncertain, and this uncertainty will be measured by one-dimensional density functionδ. In this paper, product form features were evaluated by using ECs and to establish the product style database, fuzzy case based reasoning (FCBR) model under a defined similarity measurement based on fuzzy nearest neighbors (FNN) incorporating EC was applied to extract product styles. A mathematical formalized inference system for product style was also proposed, and it also includes uncertainty measurement tool emotional cellular. A case study of style acquisition of mobile phones illustrated the effectiveness of the proposed methodology.
34
Asante, Emmanuel C., Nikitha K. Pallegar, Alica J. Hoffmann, Alicia M. Viloria-Petit e Sherri L. Christian. "Adipose Tissue from Lean and Obese Mice Induces a Mesenchymal to Epithelial Transition-Like Effect in Triple Negative Breast Cancers Cells Grown in 3-Dimensional Culture". International Journal of Molecular Sciences 21, n. 17 (3 settembre 2020): 6439. http://dx.doi.org/10.3390/ijms21176439.
Testo completoAbstract (sommario):
Breast cancer is the second leading cause of cancer-related mortality among women globally with obesity being one risk factor. Obese breast cancer patients have at least a 30% increased risk of death from breast cancer compared to non-obese breast cancer patients because they present with larger tumors and generally have increased rates of metastasis. Moreover, obese breast cancer patients respond more poorly to treatment compared to non-obese patients, particularly pre-menopausal women diagnosed with triple negative breast cancer (TNBC). To help understand the molecular mechanisms underlying the increased metastasis associated with obesity, we previously established a three-dimensional culture system that permits the co-culture of adipocytes and TNBC cells in a manner that mimics an in vivo milieu. Using this system, we demonstrate that white adipose tissue from both lean and obese mice can induce a partial mesenchymal-to-epithelial transition (MET). Triple negative breast cancer cells adopt an epithelial morphology and have an increased expression of some epithelial markers, but they maintain the expression of mesenchymal markers, furnishing the breast cancer cells with hybrid properties that are associated with more aggressive tumors. Thus, these data suggest that adipose tissue has the potential to promote secondary tumor formation in lean and obese women. Further work is needed to determine if targeting the partial MET induced by adipose tissue could reduce metastasis.
35
Hu, Xin. "Football Player Posture Detection Method Combining Foreground Detection and Neural Networks". Scientific Programming 2021 (22 giugno 2021): 1–11. http://dx.doi.org/10.1155/2021/4102294.
Testo completoAbstract (sommario):
In recent years, with the rapid development of artificial intelligence, information technology, intelligent digital video surveillance systems, real-time sports competition playback, and other technologies have emerged one after another, making the advantages of deep learning-based football posture detection tasks become more obvious. Related models and methods have been applied to the research field of sports posture estimation and have achieved great improvement, surpassing the traditional football posture estimation method based on manual design features in one fell swoop. In addition, the application of video foreground detection has developed rapidly and has great application value in sports analysis. Therefore, this paper proposes a novel football motion detection approach combining foreground detection and deep learning for real-time detection of football player posture. The main task of foreground target detection is to extract the interesting foreground target in the real monitoring scene and use it as the target of interest for subsequent analysis. Then, we propose a triple DetectNet detection framework based on deep learning technology, which can quickly and robustly realize the three-dimensional pose estimation of multiperson motion. For input, the triple DetectNet framework uses three neural networks and is executed in three stages; the first stage is to use the DetectNet (DN) network to detect the bounding box of each person separately, the second stage uses the 2DPoseNet (2DPN) network to estimate each of the corresponding two-dimensional poses of the individual, and the third stage uses the 3DPoseNet (3DPN) network to obtain the 3D pose of the person. This paper also conducted experiments on four datasets, and the results proved the superiority and success of this algorithm.
36
MARTIN, THIERRY, e DANIEL LOSS. "PHASE DIAGRAM FOR A LUTTINGER LIQUID COUPLED TO PHONONS IN ONE DIMENSION". International Journal of Modern Physics B 09, n. 04n05 (28 febbraio 1995): 495–533. http://dx.doi.org/10.1142/s0217979295000185.
Testo completoAbstract (sommario):
We consider a one-dimensional system consisting of electrons with short-ranged repulsive interactions and coupled to small-momentum transfer acoustic phonons. The interacting electrons are bosonized and described in terms of a Luttinger liquid which allows us to calculate exactly the one- and two-electron Green function. For non-interacting electrons, the coupling to phonons alone induces a singularity at the Fermi surface which is analogous to that encountered for electrons with an instantaneous attractive interaction. The exponents which determine the presence of singlet/triplet superconducting pairing fluctuations, and spin/charge density wave fluctuations are strongly affected by the presence of the Wentzel-Bardeen singularity, resulting in the favoring of superconducting fluctuations. For the Hubbard model the equivalent of a phase diagram is established, as a function of: the electron-phonon coupling, the electron filling factor, and the on-site repulsion between electrons. The Wentzel-Bardeen singularity can be reached for arbitrary values of the electron-phonon coupling constant by varying the filling factor. This provides an effective mechanism to push the system from the antiferromagnetic into the metallic phase, and finally into the superconducting phase as the electron filling factor is increased towards half-filling.
37
Tan, J. G., Yian Yian Lok e I. Pop. "Mathematical modelling of boundary layer flow over a permeable and time-dependent shrinking sheet – A stability analysis". Journal of Mechanical Engineering and Sciences 16, n. 2 (30 giugno 2022): 8837–47. http://dx.doi.org/10.15282/jmes.16.2.2022.03.0699.
Testo completoAbstract (sommario):
Micropolar fluid is one type of non-Newtonian fluid which consists of non-deformable spherical particles that suspended in viscous medium. In this paper, the problem of two-dimensional boundary layer flow over a permeable shrinking sheet with time dependent velocity in strong concentration micropolar fluid is studied theoretically. The mathematical model is governed by continuity, momentum and microrotation equations. Similarity variables are introduced so that, after performing the similarity transformation on the governing equations, the resulting system of nonlinear ordinary differential equations is then numerically solved using the program bvp4c in Matlab software. The effects of the micropolar material parameter, the unsteadiness parameter, the shrinking parameter and the mass suction parameter to the skin friction coefficient, velocity profiles and microrotation profiles are investigated. It is found that triple solutions exist for some values of the parameters that were considered. Based on the stability analysis that was performed, it showed that only two branches of solutions are categorized as stable, whereas one solution branch is unstable.
38
Pfaffhuber, Andreas A., Stefan Hendricks e Yme A. Kvistedal. "Progressing from 1D to 2D and 3D near-surface airborne electromagnetic mapping with a multisensor, airborne sea-ice explorer". GEOPHYSICS 77, n. 4 (1 luglio 2012): WB109—WB117. http://dx.doi.org/10.1190/geo2011-0375.1.
Testo completoAbstract (sommario):
The polar ocean’s sea ice cover is an unconventional and challenging geophysical target. Helicopter electromagnetic (HEM) sea-ice thickness mapping is currently limited to 1D interpretation due to traditional procedures and systems. These systems are mainly sensitive to layered structures, ideally set for the widespread flat (level) ice type. Because deformed sea ice (e.g., pressure ridges) is 3D and usually also heterogeneous, ice thickness errors up to 50% can be observed for pressure ridges using 1D approximations for the interpretation of HEM data. We researched a new generation multisensor, airborne sea ice explorer (MAiSIE) to overcome these limitations. Three-dimensional finite-element modeling enabled us to determine that more than one frequency is needed, ideally in the range 1–8 kHz, to improve thickness estimates of grounded sea-ice pressure ridges that are typical of 3D sea ice structures. With the MAiSIE system, we found a new electromagnetic concept based on one multifrequency transmitter loop and a 3C receiver coil triplet with active digital bucking. The relatively small weight of the EM components freed enough payload to include additional scientific sensors, including a cross-track lidar scanner and high-accuracy inertial-navigation system combined with dual-antenna differential GPS. Integrating the 3D ice-surface topography obtained from the lidar with the EM data at frequencies from 500 Hz to 8 kHz in [Formula: see text]-, [Formula: see text]-, and [Formula: see text]-directions, significantly increased the accuracy of sea-ice pressure-ridge geometry derived from HEM data. Initial test flight results over open water showed the proof-of-concept with acceptable sensor drift and receiver sensitivity. Noise levels were relatively high (20–250 parts-per-million) due to unwanted interference, leaving room for optimization. The 20 ppm noise level at 4.1 kHz is sufficient to map level ice thickness with 10 cm precision for sensor altitudes below 13 m.
39
CERESOLE, A., R. D’AURIA, S. FERRARA, W. LERCHE e J. LOUIS. "PICARD-FUCHS EQUATIONS AND SPECIAL GEOMETRY". International Journal of Modern Physics A 08, n. 01 (10 gennaio 1993): 79–113. http://dx.doi.org/10.1142/s0217751x93000047.
Testo completoAbstract (sommario):
We investigate the system of holomorphic differential identities implied by special Kählerian geometry of four-dimensional N=2 supergravity. For superstring compactifications on Calabi-Yau threefolds these identities are equivalent to the Picard-Fuchs equations of algebraic geometry that are obeyed by the periods of the holomorphic three-form. For one variable they reduce to linear fourth-order equations which are characterized by classical W generators; we find that the instanton corrections to the Yukawa couplings are directly related to the nonvanishing of w4. We also show that the symplectic structure of special geometry can be related to the fact that the Yukawa couplings can be written as triple derivatives of some holomorphic function F. Moreover, we give the precise relationship of the Yukawa couplings of special geometry with three-point functions in topological field theory.
40
Sorak, Marija, Aleksandar Zivanovic, Mirjana Varjacic, Goran Lukic e Goran Babic. "The ultrasonographic diagnosis of fetal encephalocele at 13th gestational week". Vojnosanitetski pregled 67, n. 1 (2010): 69–72. http://dx.doi.org/10.2298/vsp1001069s.
Testo completoAbstract (sommario):
Background. Encephalocele presents a rare anomaly of central nervous system, developed as a consequence of neural tube closing defect during early embrional development, and it is described by a baggy formation which prolaborates through the pores of the scull, filled with brain tissue, cerebrospinal liquor and entwined with meninges. According to literature search, until this day, the earliest it can be ultrasonically detected is the 13th gestation week, with the appliance of three-dimensional ultrasound. Case report. We presented 25 years old patient, ultrasonically diagnosed with occipital fetal encephalocela at the 13th gestation week. A gestation sack was located in the right uteral corn of the two-corned uterus with one cervix. The diagnosis was confirmed also by trippled value of alpha-fetoprotein in maternal serum: 75,98 IU/mL. Conclusion. Ultrasonic examination is the method of choice for prenatal detection of a fetal anomaly. It is possible to diagnose encephalocele if it prominates above the limits of the scull.
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Takayanagi, Toshiyuki, Yuya Watabe e Takaaki Miyazaki. "Reduced-Dimensionality Quantum Dynamics Study of the 3Fe(CO)4 + H2 → 1FeH2(CO)4 Spin-inversion Reaction". Molecules 25, n. 4 (17 febbraio 2020): 882. http://dx.doi.org/10.3390/molecules25040882.
Testo completoAbstract (sommario):
Many chemical reactions of transition metal compounds involve a change in spin state via spin inversion, which is induced by relativistic spin-orbit coupling. In this work, we theoretically study the efficiency of a typical spin-inversion reaction, 3Fe(CO)4 + H2 → 1FeH2(CO)4. Structural and vibrational information on the spin-inversion point, obtained through the spin-coupled Hamiltonian approach, is used to construct three degree-of-freedom potential energy surfaces and to obtain singlet-triplet spin-orbit couplings. Using the developed spin-diabatic potential energy surfaces in reduced dimensions, we perform quantum nonadiabatic transition state wave packet calculations to obtain the cumulative reaction probability. The calculated cumulative reaction probability is found to be significantly larger than that estimated from the one-dimensional surface-hopping probability. This indicates the importance of both multidimensional and nuclear quantum effects in spin inversion for polyatomic chemical reaction systems.
42
Kasai, Hidetaka, Kenichi Kato, Akihiro Hori, Masaki Takata, Susumu Kitagawa, Hiroshi Tanaka, Hidekazu Arikawa, Tatsuya Takeguchi, Masaaki Sadakiyo e Miho Yamauchi. "In situ synchrotron powder diffraction for an ionic conductor transition". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 agosto 2014): C1181. http://dx.doi.org/10.1107/s2053273314088184.
Testo completoAbstract (sommario):
In situ synchrotron X-ray powder diffraction can be one of the most powerful probes to investigate the structure evolution by a chemical reaction thanks to simultaneity of data collection. It is not, however, with ease to produce a homogeneous chemical reaction in the limited spaces, which is essential to see an atomic-scale structure evolution. We have developed an in situ capillary cell for both high-temperature H2reduction and precise humidity control at the SPring-8 BL44B2. We successfully applied this in situ system to an electronic conductor LaSr3Fe3O10, which is transformed into an ionic conductor by the two-step chemical treatments [1]. LaSr3Fe3O10has a triple-layer structure with a FeO6octahedral unit. One triple layer is bonded with another layer through van der Waals interaction. Structure refinements with in situ synchrotron powder diffraction data revealed that the H2reduction at 613 K produced in-plane oxygen vacancies, which resulted in suppression of the interlayer interaction. We found from charge density studies and Raman spectroscopy measurements that the following humidification intercalated H2O and OH-into the interlayer and intralayer, respectively. That means that H2O plays a role for suppression of three-dimensional electronic conductivity, stabilizing the intercalation structure. On the other hand, the OH-ions behave as carriers for ionic conductivity, maintaining the charge neutrality in the intralayer. Finally we determined the composition of the ionic conductor to be LaSr3Fe3O8.0(OH)1.2·2H2O, which indicates a transformation of LaSr3Fe3O10into an OH-ionic conductor. In the presentation, I will discuss the OH-ionic conduction channel based on electrostatic potentials obtained from charge densities.
43
Chan, C. T., Zhi Hong Hang e Xueqin Huang. "Dirac Dispersion in Two-Dimensional Photonic Crystals". Advances in OptoElectronics 2012 (22 ottobre 2012): 1–11. http://dx.doi.org/10.1155/2012/313984.
Testo completoAbstract (sommario):
We show how one may obtain conical (Dirac) dispersions in photonic crystals, and in some cases, such conical dispersions can be used to create a metamaterial with an effective zero refractive index. We show specifically that in two-dimensional photonic crystals with C4v symmetry, we can adjust the system parameters to obtain accidental triple degeneracy at Γ point, whose band dispersion comprises two linear bands that generate conical dispersion surfaces and an additional flat band crossing the Dirac-like point. If this triply degenerate state is formed by monopole and dipole excitations, the system can be mapped to an effective medium with permittivity and permeability equal to zero simultaneously, and this system can transport wave as if the refractive index is effectively zero. However, not all the triply degenerate states can be described by monopole and dipole excitations and in those cases, the conical dispersion may not be related to an effective zero refractive index. Using multiple scattering theory, we calculate the Berry phase of the eigenmodes in the Dirac-like cone to be equal to zero for modes in the Dirac-like cone at the zone center, in contrast with the Berry phase of π for Dirac cones at the zone boundary.
44
PASCUA, P., J. L. RUBIO, A. VIARTOLA e S. FERRER. "VISUALIZING RELATIVE EQUILIBRIA AND BIFURCATIONS BY PAINTING HAMILTONIANS ON PERSONAL COMPUTERS". International Journal of Bifurcation and Chaos 06, n. 08 (agosto 1996): 1411–24. http://dx.doi.org/10.1142/s0218127496000837.
Testo completoAbstract (sommario):
In this paper, we present a graphical tool running on a PC for studies of integrable systems of one degree of freedom with several parameters, in particular for perturbed Hamiltonian systems with symmetries whose orbit space is the two-dimensional sphere S2 after they are reduced by normalization. The pioneering work was performed by Coffey et al. [1990], who developed a graphical method on a Connection Machine in order to paint the Hamiltonian function ℋ* over phase space, instead of numerical integrations of the corresponding differential equations. We have pursued their idea and the procedure proposed here renders pictures at the rate of one picture per minute. For research or teaching activities, the above mentioned method may be used in two directions: (a) in the stability analysis of equilibria and their bifurcations in parameter space; (b) for the specification of initial conditions and the corresponding qualitative long term global dynamics, in order to make proper choices for numerical studies of the full problem. As examples of how to interact with the program, and of the different role played by physical and dynamical parameters, we consider the dynamics of the Laplace–Runge–Lenz vector in two perturbed Keplerian systems of recent interest: the generalized Van der Waals effect in the hydrogen atom, and Harrington’s model for triple stellar systems.
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Raddatz, S., E. P. Mark, A. Haking, W. Probst, M. Wiessler, M. F. Trendelenburg e H. Troester. "Development of New Marker Compounds for the Detection of Chemical Element Labels by Electron Spectroscopic Imaging (ESI)". Microscopy and Microanalysis 7, S2 (agosto 2001): 1038–39. http://dx.doi.org/10.1017/s1431927600031263.
Testo completoAbstract (sommario):
A promising aspect of ESI is its application in the detection of elemental labels introduced into biomolecules for cell and molecular biological techniques. Even though colloidal gold labeling for electron microscopy (EM) is highly developed, availability of alternative labels, especially for double or triple labeling applications would be helpful because of difficulties with gold concerning i) detection (gold diameters ≤1nm), ii) discrimination due to gold particle size variations in one size class, and iii) different labeling efficiencies depending on gold granule size. An alternative labeling molecule should contain a high concentration of a specific chemical element which is not or in minor concentrations present in the system under surveillance, and has to have the potential to be discriminated from “biological” elements by ESI.With respect to ESI, one candidate for elemental labeling is boron. It meets the criteria described above and substantial experience in the synthesis of labeling compounds exists. From the chemical point of view, the preferred labeling structure is a so called dendrimer, a highly branched regular three-dimensional monodisperse macromolecule. Dendritic structures offer a large variety of functionalities to incorporate an element detectable by energy filtering transmission electron microscopy (EFTEM).
46
Urushihara, Daisuke, Sota Kawaguchi, Koichiro Fukuda e Toru Asaka. "Crystal structure and magnetism in the S = 1/2 spin dimer compound NaCu2VP2O10". IUCrJ 7, n. 4 (27 maggio 2020): 656–62. http://dx.doi.org/10.1107/s2052252520005655.
Testo completoAbstract (sommario):
The crystal structure of the spin dimer magnet NaCu2VP2O10 was determined using single-crystal X-ray diffraction and electron diffraction. NaCu2VP2O10 displayed a non-centrosymmetric orthorhombic C2221 structure with a = 6.13860 (10) Å, b = 14.4846 (3) Å and c = 8.2392 (2) Å. The layered structure comprised CuO4 plaquettes, VO6 octahedra and PO4 tetrahedra. A pair of CuO4 plaquettes formed Cu2O6 structural dimers through edge sharing. The Cu–Cu network formed a distorted puckered-layer structure with pseudo-one-dimensional characteristics. Maximum magnetic susceptibility was observed at ∼60 K and NaCu2VP2O10 became non-magnetic upon further cooling. The spin gap between the spin-singlet non-magnetic ground state and triplet excited state was estimated to be 43.4 K. Thus, NaCu2VP2O10 was assumed to be an alternating chain system with a singlet ground state of dimer origin. The V5+ ions in the VO6 octahedra showed large off-centre displacements along the [110] direction in the primitive perovskite structure, which were attributed to the pseudo-Jahn–Teller distortion of d 0 transition metals.
47
Sefidan, Ali M., Mehdi E. Sangari, Mathieu Sellier, Md Imran Hossen Khan e Suvash C. Saha. "Modeling of Multi-Layer Phase Change Material in a Triplex Tube under Various Thermal Boundary Conditions". Energies 15, n. 9 (9 maggio 2022): 3465. http://dx.doi.org/10.3390/en15093465.
Testo completoAbstract (sommario):
Nowadays, limited energy resources face ever-growing demands of the modern world. One engineering approach to mitigate this problem which has received considerable attention in recent years is using latent heat thermal storage (LHTS) systems, a significant opportunity which is provided by phase change materials (PCMs). In the present study, a numerical investigation was devoted to estimate the simultaneous freezing and melting processes of a double-layer PCM in terms of heat transfer and fluid flow phenomena. A double-pipe cylindrical channel with two compartments, A and B, was considered for locating two PCMs of RT28 and RT35 in various arrangements. The inner and outer walls were exposed to both hot and cold heat transfer fluids (HHTFs and CHTFs, respectively) beginning with solid or liquid initial state, which led to solid–liquid phase change process through PCMs. The numerical simulation was handled by a two-dimensional finite volume method (FVM) with a fixed Rayleigh number of 106 in which conduction and convection heat transfer mechanisms are taken into account. The effects of employing double-layer PCM and their arrangements, inner and outer walls’ boundary conditions, and initial statuses of PCMs are discussed, and the details of the compared results are shown in the form of temperature and liquid fraction variations over time.
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BHATTACHARYA, ARUP K., e SYED S. HAIDER. "A VLSI IMPLEMENTATION OF THE INVERSE DISCRETE COSINE TRANSFORM". International Journal of Pattern Recognition and Artificial Intelligence 09, n. 02 (aprile 1995): 303–14. http://dx.doi.org/10.1142/s0218001495000146.
Testo completoAbstract (sommario):
The Inverse Discrete Cosine Transform (IDCT) is an important function in HDTV, digital TV and multimedia systems complying with JPEG or MPEG standards for video compression. However, the IDCT is computationally intensive and therefore very expensive to implement in VLSI using direct matrix multiplication. By properly arranging the input coefficient sequence and the output data, the rows and columns of the transform matrix can be reordered to build modular regularity suitable for custom implementation in VLSI. This regularity can be exploited, so that a single permutation can be used to derive each output column from the previous one using a circular shift of an accumulator’s input data multiplied in a special sequence. This technique, using only one 1-dimensional IDCT processor and seven constant multipliers, and its implementation are presented. Operation of 58 MHz under worst case conditions is easily achieved, thus making the design applicable to a wide range of video and real time image processing applications. Fabricated in 0.5 micron triple metal CMOS technology, the IDCT contains 70,000 transistors occupying 7 mm2 square silicon. The design has been used on an AT&T MPEG video decoder chip.
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Denissenkov, Pavel A., Falk Herwig, Paul Woodward, Robert Andrassy, Marco Pignatari e Samuel Jones. "The i-process yields of rapidly accreting white dwarfs from multicycle He-shell flash stellar evolution models with mixing parametrizations from 3D hydrodynamics simulations". Monthly Notices of the Royal Astronomical Society 488, n. 3 (12 luglio 2019): 4258–70. http://dx.doi.org/10.1093/mnras/stz1921.
Testo completoAbstract (sommario):
ABSTRACT We have modelled the multicycle evolution of rapidly accreting CO white dwarfs (RAWDs) with stable H burning intermittent with strong He-shell flashes on their surfaces for 0.7 ≤ MRAWD/M⊙ ≤ 0.75 and [Fe/H] ranging from 0 to −2.6. We have also computed the i-process nucleosynthesis yields for these models. The i process occurs when convection driven by the He-shell flash ingests protons from the accreted H-rich surface layer, which results in maximum neutron densities Nn, max ≈ 1013–1015 cm−3. The H-ingestion rate and the convective boundary mixing (CBM) parameter ftop adopted in the one-dimensional nucleosynthesis and stellar evolution models are constrained through three-dimensional (3D) hydrodynamic simulations. The mass ingestion rate and, for the first time, the scaling laws for the CBM parameter ftop have been determined from 3D hydrodynamic simulations. We confirm our previous result that the high-metallicity RAWDs have a low mass retention efficiency ($\eta \lesssim 10{{\ \rm per\ cent}}$). A new result is that RAWDs with [Fe/H] $\lesssim -2$ have $\eta \gtrsim 20{{\ \rm per\ cent}}$; therefore, their masses may reach the Chandrasekhar limit and they may eventually explode as SNeIa. This result and the good fits of the i-process yields from the metal-poor RAWDs to the observed chemical composition of the CEMP-r/s stars suggest that some of the present-day CEMP-r/s stars could be former distant members of triple systems, orbiting close binary systems with RAWDs that may have later exploded as SNeIa.
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Wang, Yanzhang, Ming Liu, Jialin Zhang, Kaiguang Zhu, Shoupeng Deng, Yue Zhang, Yifan Bai e Shilong Wang. "The fault detection of transmitting current encoded by m-sequence using triple-correlation function in helicopter-borne electromagnetic method". Review of Scientific Instruments 93, n. 7 (1 luglio 2022): 074501. http://dx.doi.org/10.1063/5.0090992.
Testo completoAbstract (sommario):
An m-sequence is applied to the helicopter-borne electromagnetic method system for the first time, and there are many problems to be solved, one of which is the detection of the quality of the transmitting current waveform, which directly affects the resource survey results. In this research, we found that the triple-correlation function (TCF) can reveal the bit integrity characteristics of the m-sequence encoded transmitting current. On this basis, this paper proposes to extract the three-dimensional information of the normalized TCF plot by using a peak detection method and, then, proposes to use a dual-threshold method to clarify the detection results. The whole process realizes the fault detection of the transmitting current waveform. We propose a reasonable transmitting current modeling method and conduct 1200 random experiments in 12 groups. The statistics of the experimental results show that when the number of missing bits is 1, 2, 4, and 8, the fault detection accuracy can reach more than 83%. A comparative experiment using the Field Programmable Gate Array. in the laboratory validates the feasibility of the fault detection method. This method is beneficial to improve the quality of detection data and avoid economic losses caused by invalid detection flights.