Search results for "SSB"
showing 10 items of 537 documents
Structural and magnetic investigations of the mixed-valence Fe(II,III) two-dimensional layer complex, [Fe2(II) Fe2(III)(HCOO)10(C6H7N)6]n.
2004
The structure of the complex, [Fe2(II)Fe2(III)(HCOO)10(C6H7N6)n, (1) exhibits a neutral two-dimensional layer network of alternating iron(II) and iron(III) ions, bridged equatorially by formate groups. All iron atoms are octahedrally coordinated, with iron(III) coordinating axially to one gamma-picoline and one formate group, while the iron(II) centers interact axially with two gamma-picoline groups, above and below the layer plane. The complex crystallizes in the triclinic space group P1 at all studied temperatures [at 120 K, the cell dimensions are: a = 10.228(1), b = 12.071(1), c = 12.072(1) A, alpha = 89.801(2), beta = 71.149(2), gamma = 73.371(2) degrees]. An intralayer antiferromagnet…
Molecular Sensors for Moisture Detection by Mössbauer Spectroscopy
2002
A parameter of importance in various industrial and commercial applications is sensitivity to moisture. A new class of molecular sensors which enable the qualitative and quantitative determination of air moisture (high selectivity and sensitivity) by application of Mossbauer spectroscopy as the probe technique has been investigated. The electronic properties of the iron-containing sensor depend upon the presence of moisture which is taken up by it and this process is accompanied by a change in electronic spin ground state which can be detected by Mossbauer spectroscopy. The sensor is suitable for in-field and industrial application using the recently developed Mossbauer spectrometer MIMOS I…
Wilson maxillary curve analyzed by cbct a study on normocclusion and malocclusion individuals
2013
The anatomy of dental compensation curve in the frontal plane described by George H. Wilson is one of the occlusal determinants of orthodontic treatment. However, there is few published comparing malocclusion and normocclusion individuals. Objectives: The aim of this study is to compare the curve of Wilson at first and second maxillary molars, normocclusion pattern and malocclusion pattern, with and without bilateral posterior crossbite, using angular references in CBCT studies. Material and Methods: We analyzed 10 cases of malocclusion with bilateral posterior crossbite, 10 cases of malocclusion without bilateral posterior crossbite and 10 cases with non orthodontic normocclusion (patients…
Nonsurgical treatment of an adult with skeletal Class III malocclusion, anterior crossbite, and an impacted canine
2021
Class III malocclusion presents some complexity in terms of diagnosis and treatment and affects not only the jaws but the whole craniofacial complex. Besides, functional forward displacement of the mandible may be diagnosed in a patient presenting Class III malocclusion, as the 2 entities are not incompatible or mutually exclusive. This case report describes the multidisciplinary, nonsurgical, orthodontic treatment of an adult patient with a skeletal Class III malocclusion, anterior crossbite, and a palatally impacted canine, treated with fixed appliances and skeletal anchorage. To upright the mandibular molars, distalize the whole mandibular arch, and avoid excessive inclination of maxilla…
The dynamics of (57)Fe nuclei in Fe(III)-DNA condensates.
2001
Abstract The dynamics of iron nuclei in the condensates obtained by interaction of Fe III with DNA, Fe III (DNA monomer) 2 , have been investigated by variable temperature 57 Fe Mossbauer spectroscopy. Studies were effected on gel and freeze-dried samples, obtaining nearly coincident values of the parameters isomer shift and nuclear quadrupole splitting in T ranges 20–260 K. Functions ln( A T / A 77.3 ) vs. T , here employed to investigate the dynamics of Fe nuclei, showed linear trends in the T ranges 20–150 and 150–260 K, respectively, the latter with larger slopes. Data coincided for gelled and freeze-dried specimens. No variation of δ or Δ E parameters occurred at the two T intervals, w…
Spin Crossover in a Supramolecular Fe4II [2×2] Grid Triggered by Temperature, Pressure, and Light
2000
A multiplex electronic switch on the molecular level has been realized by using a tetranuclear FeII complex of the [2×2] grid type. The four metal ions can be switched stepwise between their high-spin and low-spin states by temperature, pressure, and light, thus representing a triple level, triple switch system as illustrated in the picture.
Synthesis and immobilization of molecular switches onto titaniumdioxide nanowires
2009
Abstract The precursor [Fe III (L)Cl (L = N , N ′-bis(2′-hydroxy-3′-methyl-benzyliden)-1,7-diamino-4-azaheptane) is combined with [Mo(CN) 8 ] 4− yields a star shaped nona-nuclear cluster, [Mo IV {(CN)Fe III (L)} 8 ]Cl 4 . This Fe 8 Mo molecule is a high-spin system at room temperature. On cooling to 20 K some of the iron(III) centres in the molybdenum(IV)-star switch to the low-spin state as proven by Mossbauer spectroscopy. This molecule was deposited on TiO 2 nanowires by electrostatic interactions between the cluster cations and the surface functionalized titanium oxide nanowire. The synthesis and surface binding of the multistable molecular switch was demonstrated using IR and UV–Vis s…
Role of Indian fluxes in the intraseasonal 10-30 days variability of the African monsoon.
2018
12 pages; International audience; This study focused on the influence of Indian monsoon on the 10-30 days variability of the West African monsoon. One relies on the 500-300 hPa moisture fluxes calculated from specific wind and moisture fields from the ERAInterim reanalysis over the 1998-2008 period. These fluxes carry a signal of a spatio-temporal Rossby wave structure propagating westward from India. In the active phase of high convection of this wave, 500-300 hPa fluxes are Easterly. This high-tropospheric Rossby wave signal from the Indian monsoon area would modulate the dynamics over the Sahel.
NQR/NMR and Mössbauer spectroscopy of sulfides: potential and versatility
2013
Nuclear quadrupole resonance (NQR), nuclear magnetic resonance (NMR) and nuclear gamma-resonance (NGR or Mossbauer Effect) methods are generally described as highly sensitive tools in studies of local electronic structure and symmetry in solid-state materials. This is due to high informativity in electronic structure investigations, high resolution in phase-structural diagnostics (down to nano-scale), possibility to study polycrystalline and complex compounds, and to the non-destructive character of these methods. As applied to Earth sciences, both NQR/NMR and Mossbauer spectroscopy methods contribute to mineralogical material science and mineral physics. Another important aspect is the fac…
Investigation of ultrathin iron and iron/nickel layers prepared from Langmuir-Blodgett films
1996
Oxidic and metallic iron and iron/nickel multilayers, formed after thermal and chemical treatment of Langmuir-Blodgett films, were investigated. Reduced iron-stearate multilayers were compared with evaporated films concerning their phase composition and their lateral homogeneity. The sequence of metallic and oxidic iron in the films after reduction was determined. Oxidic iron/nickel mixed layers can be prepared from Langmuir-Blodgett films, in which a magnetically non-ordered Fe3+ phase exhibiting a distribution of the quadrupole splitting is observed. After reduction of such layers, two metallic iron phases appear dependent on the nickel concentration. The hyperfine field distribution of t…