Search results for " Transition"
showing 10 items of 2751 documents
Conformational substates of ferricytochrome c revealed by combined optical absorption and electronic circular dichroism spectroscopy at cryogenic tem…
2010
We have investigated the heterogeneity of the Fe(III)–Met80 linkage of horse heart ferricytochrome c by probing the 695 nm charge transfer band with absorption and electronic circular dichroism (ECD) spectroscopy. In order to verify the connection between conformational substates of the Fe(III)–Met80 linkage and the 695 nm band spectral heterogeneity, we have performed experiments as a function of pH (neutral and acidic) and temperature (room and 20 K). At room temperature, the ECD spectrum is blue shifted with respect to the absorption one; the shift is more pronounced at acidic pH and is compatible with the presence of sub-bands. ECD measurements at 20 K highlighted the heterogeneous natu…
Chiral spin crossover nanoparticles and gels with switchable circular dichroism
2015
Spin crossover complexes represent spectacular examples of molecular switchable materials. We describe a new approach towards homochiral coordination nanoparticles of [Fe(NH2trz)3](L-CSA)2 (NH2trz = 4-amino-1,2,4-triazole, L-CSA = L-camphorsulfonate) that display an abrupt switch of chiral properties associated with a cooperative spin transition. This is an original method that generates stable and additive-free colloidal solutions of nanoparticles with a spin transition around room temperature. The introduction of a chiral anion to the coordination framework makes these nanoparticles display specific chiro-optical (circular dichroism) properties that are different in high and low spin stat…
Use of Ultrasound in Reconditioning by Welding of Tools Used in the Process of Regenerating Rubber
2018
Addressing the problem of reconditioning large parts is of particular importance, due to their value and to the fact that the technologies for their reconditioning are very complex. The tools used to refine regenerated rubber which measure 660 mm in diameter and 2130 mm in length suffer from a rather fast dimensional wear. Within this research, the authors looked for a welding reconditioning procedure that would allow a very good adhesion between the deposited material layer and the base material. In this regard, the MAG (Metal Active Gas) welding process was used, but the ultrasonic activation of the welding process was also considered. Thus, the wire used for welding was activated conside…
Ultrafast dynamics of halogens in rare gas solids
2007
We perform time resolved pump-probe spectroscopy on small halogen molecules ClF, Cl2, Br2, and I2 embedded in rare gas solids (RGS). We find that dissociation, angular depolarization, and the decoherence of the molecule is strongly influenced by the cage structure. The well ordered crystalline environment facilitates the modelling of the experimental angular distribution of the molecular axis after the collision with the rare gas cage. The observation of many subsequent vibrational wave packet oscillations allows the construction of anharmonic potentials and indicate a long vibrational coherence time. We control the vibrational wave packet revivals, thereby gaining information about the vib…
The effect of the internal architecture of polymer micronetwork colloids on the dynamics in highly concentrated dispersions
2007
Motivated by the finding that colloidal dispersions of polymer micronetwork spheres with a cross-link density of 1:50 (inverse number of monomer units between crosslinks) show significant deviations from the dynamics of hard spheres in the colloid glass as seen by dynamic light scattering (DLS) (E. Bartsch, V. Frenz, H. Sillescu J. Non — Cryst. Solids 172–174 (1994), 88–97), we have undertaken a systematic study of the effect of the crosslink density on the dynamics at high concentrations. Long-time self-diffusion coefficients D S L and collective diffusion coefficients D c were measured for colloids with crosslink densities of 1:10, 1:20 and 1:50 by forced Rayleigh scattering (FRS) and the…
Order-disorder phase transition in random-walk networks
2004
In this paper we study in detail the behavior of random-walk networks (RWN's). These networks are a generalization of the well-known random Boolean networks (RBN's), a classical approach to the study of the genome. RWN's are also discrete networks, but their response is defined by small variations in the state of each gene, thus being a more realistic representation of the genome and a natural bridge between discrete and continuous models. RWN's show a clear transition between order and disorder. Here we explicitly deduce the formula of the critical line for the annealed model and compute numerically the transition points for quenched and annealed models. We show that RBN's and the annealed…
Urban gardens and institutional fences: The case of communal gardens in Turin
2017
Urban gardens take on different forms and meanings, which vary depending on the socio-economic context where they located/used and how it evolves over time. This makes a garden comparable to a micro-social ecosystem, different from other gardens and ever changing. As with every social-ecosystem resulting from a territorialisation process, there is a certain degree of social inertia that makes it difficult for outsiders with new motivations and demanding new spaces to enter into the "garden ecosystem". Drawing on existing literature and fieldwork in two urban communal gardens in Turin, the paper is mainly concerned with the spatiotemporal dimension of urban gardening, with a special focus on…
A longitudinal examination of the transition to symbolic communication in the second year of life
2003
Between 10 and 24 months of age, children progress from communicating through conventional signals to communicating through symbols in a variety of situations. The present study investigates this transition analysing mother–child communication frames and the child’s communicative acts, and tracing the developmental changes in both frames and communicative acts. Four children (2 girls, 2 boys) and their mothers were observed longitudinally and extensively, from 10 to 24 months of age, using a multiple case-study method. Through the detailed investigation of these single cases, clear developmental trajectories were found, showing that conventional frames and representational gestures ‘bridge’…
Étude exploratoire des obstacles à la transition universitaire selon le vécu d’étudiants français et belges
2020
International audience; Transition to Higher Education constitutes a challenging adjustment step for students that deserves major investigation. Yet, the transition obstacles are still overlooked. Most of international studies focused on individual predictors of adjustment and consider transition to Higher Education as a universal and invariant process. However, contextual characteristics of educational environment should be considered because they don’t imply the same requirements for adjustment. In order to address this limitation, this paper realized an exploratory comparison of first year student experience between a French and a Belgian university. The results highlighted similarities …
COMPREHENSIVE TEACHER’S PROFESSIONALISM FOR CONTENT AND LANGUAGE INTEGRATED PROVISION
2019
T opicality of the problem is determined by several factors as well as the amendments on the Education Law and the General Education Law, which provide for a gradual transition to the acquisition of general secondary education in Latvian only, educational content reform and teachers experience to work in an ethnically and linguistically heterogeneous environment. The aim of the study is to analyse comprehensive school teachers theoretical background and practice experience to work in the content and language integrated teaching and learning approach. Because language not a subject only but a mean of acquiring other subjects in the comprehensive school, too, all teachers need theoretical kno…