Search results for "thermal [correlation function]"
showing 10 items of 1923 documents
Heterobimetallic MOFs containing tetrathiocyanometallate building blocks: Pressure-induced spin crossover in the porous {Fe II(pz)[Pd II(SCN) 4]} 3D …
2012
Here we describe the synthesis, structure, and magnetic properties of two related coordination polymers made up of self-assembling Fe(II) ions, pyrazine (pz), and the tetrathiocyanopalladate anion. Compound {Fe(MeOH) 2[Pd(SCN) 4]}·pz (1a) is a two-dimensional coordination polymer where the Fe(II) ions are equatorially coordinated by the nitrogen atoms of four [Pd(SCN) 4] 2- anions, each of which connects four Fe(II) ions, forming corrugated layers {Fe[Pd(SCN) 4]} ∞. The coordination sphere of Fe(II) is completed by the oxygen atoms of two CH 3OH molecules. The layers stack one on top of each other in such a way that the included pz molecule establishes strong hydrogen bonds with the coordin…
Phase and structural transformations in annealed copper coatings in relation to oxide whisker growth
2015
Abstract We describe structural and phase transformation in copper coatings made of microparticles during heating and annealing in air in the temperature range up to 400 °C. Such thermal treatment is accompanied by intensive CuO nanowhisker growth on the coating surface and the formation of the layered oxide phases (Cu 2 O and CuO) in the coating interior. X-ray diffraction and focused ion beam (FIB) are employed to characterize the multilayer structure of annealed copper coatings. Formation of volumetric defects such as voids and cracks in the coating is demonstrated.
Hemocyanin conformational changes associated with SDS-induced phenol oxidase activation.
2007
The enzymatic activity of phenoloxidase is assayed routinely in the presence of SDS. Similar assay conditions elicit phenoloxidase activity in another type 3 copper protein, namely hemocyanin, which normally functions as an oxygen carrier. The nature of the conformational changes induced in type 3 copper proteins by the denaturant SDS is unknown. This comparative study demonstrates that arthropod hemocyanins can be converted from being an oxygen carrier to a form which exhibits phenoloxidase activity by incubation with SDS, with accompanying changes in secondary and tertiary structure. Structural characterisation, using various biophysical methods, suggests that the micellar form of SDS is …
Thermally Induced Structural Modification of Silica Nanoparticles Investigated by Raman and Infrared Absorption Spectroscopies
2010
We report an experimental investigation by Raman and infrared (IR) absorption spectroscopies on the structural modifications induced by isochronal thermal treatments on amorphous SiO2 nanoparticles (fumed silica). In particular, three different commercial types of this material, characterized by particle mean diameters of 7, 14, and 40 nm, were subjected to thermal treatments from 100 up to 1000 °C. We found that some properties of fumed silica, such as the SiOSi mean bond angle, ring size distribution, and surface adsorbed water content, are drastically different from those of common bulk silica materials and intimately related to the particles' dimension. The SiOSi mean bond angle, probed…
Insights Into the Mechanisms of Phreatic Eruptions From Continuous High Frequency Volcanic Gas Monitoring: Rincón de la Vieja Volcano, Costa Rica
2019
OVSICORI Understanding the trigger mechanisms of phreatic eruptions is key to mitigating the effects of these hazardous but poorly forecastable volcanic events. It has recently been established that high-rate volcanic gas observations are potentially very suitable to identifying the source processes driving phreatic eruptions, and to eventually detecting precursory changes prior to individual phreatic blasts. In February-May 2017, we deployed a Multi-GAS instrument to continuously monitor gas concentrations in the crater lake plume of Rincón de la Vieja, a remote and poorly monitored active volcano in Costa Rica, site of frequent phreatic/phreatomagmatic eruptions. Forty-two phreatic/phreat…
Evidence for Photoinduced Hole Coupling in BaTiO3:Co
1995
A possible photoinduced correlation mechanism in BaTiO 3 : Co is described. The underlying microscopic process is a local hole photoinjection at a Co 3+ site close to a preexisting metastable hole, The Jahn-Teller field at the Co 2+ site transfers this pair of holes in the next cell along the rhombic direction [111] before normal polaronic or band conduction. The spatial extension of this correlation depends on a characteristic «delocalization» length. This unstable conductive state appears to be possibly frozen in a permanent way below T c
Hot electron effects in metallic single electron components
1996
Thermalisation of single electron devices is of considerable current interest because of its fundamental and practical consequences. We present experimental evidence of the effect of electrode volume and its shape on thermal equilibration of small metallic islands for single electron tunnelling. Heat transport between the conduction electrons and the lattice in a metal is commonly accepted to obey the ∝Te5-T0/5 law at low electron and lattice temperatures,Te andT0, respectively. We have investigated the power law and found that it obeys the ∝T5 law only for the smallest islands, and in the majority of the cases considered, it rather follows a law ∝Tp, wherep<5. The thermal coupling can be i…
WS2/MoS2 Heterostructures via Thermal Treatment of MoS2 Layers Electrostatically Functionalized with W3S4 Molecular Clusters
2020
The preparation of 2D stacked layers that combine flakes of different nature, gives rise to countless number of heterostructures where new band alignments, defined at the interfaces, control the electronic properties of the system. Among the large family of 2D/2D heterostructures, the one formed by the combination of the most common semiconducting transition metal dichalcogenides WS2/MoS2, has awaken great interest due to its photovoltaic and photoelectrochemical properties. Solution as well as dry physical methods have been developed to optimize the synthesis of these heterostructures. Here a suspension of negatively charged MoS2 flakes is mixed with a methanolic solution of a cationic W3S…
Levels of 186Re populated in thermal neutron capture reaction
2015
Levels of 186 Re have been studied in the thermal neutron capture reaction with an enriched 185 Re target. Evaluation of spectrum measured with GAMS5 allowed to obtain energies and intensities of more than 500 γ -lines assigned to 186 Re. Most of the obtained transitions have been placed in the model-independent level scheme of the doubly odd 186 Re nucleus, taking into account the available data of earlier experiments as well as the results of recent 187 Re(p, d )186 Re reaction measurements. Structure of the 186 Re low-lying levels has been analysed in terms of the particle-plus-rotor coupling model.
WS 2 /MoS 2 Heterostructures through Thermal Treatment of MoS 2 Layers Electrostatically Functionalized with W 3 S 4 Molecular Clusters
2020
The preparation of 2D stacked layers combining flakes of different nature gives rise to countless numbers of heterostructures where new band alignments, defined at the interfaces, control the electronic properties of the system. Among the large family of 2D/2D heterostructures, the one formed by the combination of the most common semiconducting transition metal dichalcogenides, WS2 /MoS2 , has awakened great interest owing to its photovoltaic and photoelectrochemical properties. Solution as well as dry physical methods have been developed to optimize the synthesis of these heterostructures. Here, a suspension of negatively charged MoS2 flakes is mixed with a methanolic solution of a cationi…