Search results for "transition [photon]"
showing 10 items of 273 documents
Una revolución científica a la que Educación Química quiere contribuir
2014
AbstractSustainability Science aims to integrate the study of social development and natural processes to fa a new paradigm thatvour both of them and make possible the transition to Sustainability. This deep scientific revolution cannot be the result of just a new knowledge discipline: it must become a new paradigm that impregnates the ensemble of scientific disciplines and social activities.ResumenLa Ciencia de la Sostenibilidad tiene como objetivo integrar el estudio del desarrollo social y los procesos naturales para favorecer a ambos y posibilitar la transición hacia la sostenibilidad. Esta profunda revolución científica no puede ser el resultado de solo una nueva disciplina del conocim…
Transition to adulthood and recession: a qualitative study
2016
While the transition to adulthood has been broadly examined, less is known about the impact of economic recession on the well-being and psychosocial functioning of young people. The present study used qualitative interviews with 12 college students to understand their experience. Consensual qualitative research was used to analyse data and develop core themes around young people’s experiences. Interviews focused on how young people perceived the impact of the economic recession on their social context and on emotional, behavioural, and interpersonal dimensions. Although students showed a proactive attitude in dealing with the crisis, findings highlighted a negative impact on psychological f…
The manifestation of dipoles clustering in paraelectric phase of disordered ferroelectrics
2001
Abstract We predict the existence of Griffiths phase in the dielectrics with concentrational crossover between dipole glass (electric analog of spin glass) and ferroelectricity. The peculiar representatives of above substances are KTaO3: Li, Nb, Na or relaxor ferroelectrics like Pb1−xLaxZr0.65Ti0.35O3. Since this phase exists above ferroelectric phase transition temperature (but below that temperature for ordered substance), we call it “para-glass phase”. We assert that the difference between paraelectric and para-glass phase of above substances is the existence of clusters (inherent to “ordinary” Griffiths phase in Ising magnets) of correlated dipoles. We show that randomness play a decisi…
Effect of structural and compositional inhomogeneities on spin-glass transition in Hg1−x−yCrxMnySe crystals
2004
Abstract We report experimental results on the growth of Hg 1 −x−y Cr x Mn y Se crystals and their magnetic susceptibility χ ( T ) in dependence on the crystal structure and composition. It was found that the crystals with the Mn composition y =0.01–0.08 exhibit the spin-glass transition temperature T g =100–110 K. An increase of y value leads to the saturation of the χ max and T g characteristics in the composition ranges of y >0.06 and y >0.02, respectively. This phenomenon is explained as a result of phase-separated magnetic behavior caused by the formation of HgCr 2 Se 4 inclusions and textures.
What we look at in paintings: A comparison between experienced and inexperienced art viewers
2016
How do people look at art? Are there any differences between how experienced and inexperienced art viewers look at a painting? We approach these questions by analyzing and modeling eye movement data from a cognitive art research experiment, where the eye movements of twenty test subjects, ten experienced and ten inexperienced art viewers, were recorded while they were looking at paintings. Eye movements consist of stops of the gaze as well as jumps between the stops. Hence, the observed gaze stop locations can be thought as a spatial point pattern, which can be modeled by a spatio-temporal point process. We introduce some statistical tools to analyze the spatio-temporal eye movement data, a…
Dynamical susceptibility from simulations of a mean field Potts glass
2004
Abstract We present results of the non-linear dynamic susceptibility χ(t) in a mean field Potts glass from simulations in a wide range of temperatures above the theoretically predicted dynamical transition, for various system sizes up to 2560 spins. χ(t) has a maximum, with a height that diverges like (T−TD)−α, with α≈1. The timescale t ∗ associated with this maximum also approaches a singularity, and we show that its behavior is compatible with the relaxation time of the standard time-dependent spin autocorrelation function, also with respect to finite size effects. We find that χ(t) for temperatures near the transition temperature TD satisfies a dynamical scaling property.
Guest Removal and External Pressure Variation Induce Spin Crossover in Halogen-Functionalized 2-D Hofmann Frameworks.
2020
The effect of halogen functionalization on the spin crossover (SCO) properties of a family of 2-D Hofmann framework materials, [FeIIPd(CN)4(thioX)2]·2H2O (X = Cl and Br; thioCl = (E)-1-(5-chlorothiophen-2-yl)-N-(4H-1,2,4-triazol-4-yl)methanimine) and thioBr = (E)-1-(5-bromothiophen-2-yl)-N-(4H-1,2,4-triazol-4-yl)methanimine)), is reported. Inclusion of both the chloro- and bromo-functionalized ligands into the Hofmann-type frameworks (1Cl·2H2O and 2Br·2H2O) results in a blocking of spin-state transitions due to internal chemical pressure effects derived by the collective steric bulk of the halogen atoms and guest molecules. Cooperative one-step SCO transitions are revealed by either guest r…
Investigation of Temperature-Induced Phase Transitions in DOPC and DPPC Phospholipid Bilayers Using Temperature-Controlled Scanning Force Microscopy
2004
Under physiological conditions, multicomponent biological membranes undergo structural changes which help define how the membrane functions. An understanding of biomembrane structure-function relations can be based on knowledge of the physical and chemical properties of pure phospholipid bilayers. Here, we have investigated phase transitions in dipalmitoylphosphatidylcholine (DPPC) and dioleoylphosphatidylcholine (DOPC) bilayers. We demonstrated the existence of several phase transitions in DPPC and DOPC mica-supported bilayers by both atomic force microscopy imaging and force measurements. Supported DPPC bilayers show a broad L(beta)-L(alpha) transition. In addition to the main transition …
Calculation of modification of alkali metal atomic transition probability in strong external magnetic field and its application
2010
International audience; Interaction of alkali atoms with external magnetic field induced a splitting and a shift of their energy levels. We have study this interaction for external field from 0 to 5000 Gauss when the alkali vapor is confined in submicron thin vapor cell with thickness L = λ/2. Rubidium and Sodium vapors have been studied. The Hamiltonian can be expressed as the sum of the unperturbated atomic Hamiltonian and the so-called Zeeman Hamiltonian. The probability of a transition, induced by the laser electric field is proportional to the square of the transfer coefficients modified by the presence of the magnetic field. We will show that the strong nonlinearity of the transition …
Effect of water on glass transition in starch/sucrose matrices investigated through positron annihilation lifetime spectroscopy: a new approach
2011
Glass transition is studied through positron annihilation lifetime spectroscopy (PALS) in maize starch matrices containing 10 (batch STS10) and 20 (STS20) w/w% sucrose, as a function of temperature (T) and water content (c(w)). To circumvent important losses of water upon heating while recording the PALS spectra, a new method is developed: instead of a series of measurements of τ(3), the triplet positronium lifetime, at different T, the latter is kept constant and the series relates to c(w), which is left to decrease at a constant rate. Similarly to the changes in τ(3) with T, the τ(3)vs. c(w) plots obtained show a smooth linear increase until a break, denoting the occurrence of glass trans…