Preparation of silver behenate coatings to provide low- to mid-angle diffraction calibration

Blanton, Thomas N.; Barnes, C. L.; Lelental, M.

doi:10.1107/s0021889899012388

Cited by 70 publications

(53 citation statements)

References 5 publications

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“…It is performed on suspension gels and even solids and requires little or no sample preparation. Silver is part of virtually every SAXS experiment because Ag-behenate is used for q calibration [96]. The heavier elements, such as Ag, are easy to observe with SAXS because of their high electron contrast, and a number of studies describe size and structure of AgNP-based materials [97].…”

Section: Analysis Of Engineered Nanomaterials In Complex Samplesmentioning

confidence: 99%

Analysis of engineered nanomaterials in complex matrices (environment and biota): General considerations and conceptual case studies

Kammer

Ferguson

Holden

et al. 2011

Enviro Toxic and Chemistry

403

241

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Section: Analysis Of Engineered Nanomaterials In Complex Samplesmentioning

confidence: 99%

Analysis of engineered nanomaterials in complex matrices (environment and biota): General considerations and conceptual case studies

Kammer

Ferguson

Holden

et al. 2011

Enviro Toxic and Chemistry

403

241

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“…Experiments were conducted using Microcalix (Centre National de la Recherche Scientifique, Châtenay-Malabry, France), an apparatus allowing simultaneous timeresolved synchrotron X-ray diffraction as a function of temperature (XRDT) and high sensitivity differential scanning calorimetry (DSC) to be carried out on the same sample, as reported previously [4,9,15,19,23]. The recording of XRDT patterns and the calibration of the detectors and the calorimeter were conducted as previously reported [4,9,10,19,23].…”

Section: Combined Xrdt and Dsc Measurementsmentioning

confidence: 99%

“…The recording of XRDT patterns and the calibration of the detectors and the calorimeter were conducted as previously reported [4,9,10,19,23]. The analysis of the XRDT patterns was performed as previously described [9,14].…”

Section: Combined Xrdt and Dsc Measurementsmentioning

confidence: 99%

Dromedary milk fat: thermal and structural properties 2. Influence of cooling rate

Karray¹,

Lopez

Lesieur

et al. 2005

Lait

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-The crystallization behavior of anhydrous dromedary milk fat (ADMF) was examined using Microcalix (Centre National de la Recherche Scientifique, Châtenay-Malabry, France), an instrument coupling time-resolved synchrotron X-ray diffraction as a function of temperature (XRDT) at both small and wide angles and high-sensitivity differential scanning calorimetry (DSC) at an intermediate (1 °C·min -1 ) and at a fast (5 °C·min -1 ) cooling rate from 60 to -20 °C, together with their subsequent melting at 1 °C·min -1 . Upon cooling at 1 °C·min -1 , the crystallization of ADMF started at about 24 °C with the formation of a lamellar structure with a 46.9 Å period corresponding to a double-chain length molecular stacking and hexagonal chain packing (2L 1 α). From 20 °C, a major crystalline species also with double-chain lengths of 42.5 Å and orthorhombic chain packing (2L 2 β') was observed. The successive crystallizations of varieties 2L 1 and 2L 2 were correlated with the apparition of two large exothermal events recorded simultaneously by thermal analysis (DSC). However, comparison of XRDT and DSC recordings revealed the presence of a third exothermal peak probably related to a transition α → β'. At fast cooling (5 °C·min -1 ) of ADMF, three crystalline varieties were formed: the 2L 1 α (47.6 Å), 2L 2 β' (42.15 Å) and a new crystalline structure with 4 chain lengths: 4L β' of period 84.5 Å, while three endotherms were recorded by DSC. This last crystalline form which had never been characterized until now, likely corresponds to the accumulation of defects in the stable 2L β' form (42.15 Å) resulting from fast cooling and then to a local lack of symmetry in the 4L cell along the c axis of the crystals. This lack of symmetry was released during a transition 4L → 2L observed upon heating. A polymorphic transition α →β' was always observed upon ADMF heating following cooling at either 5 or 1 ° C·min -1 . Compared with the slow cooling at 0.1 °C·min -1 which was studied in the previous paper of this series, ADMF presented different structural and thermal properties. Indeed, the cooling at 1 °C·min -1 and 5 °C·min -1 generated an unstable crystalline form (α) that was not found at slow cooling at 0.1 °C·min -1 . However, the major stable form 2L β' was always observed in the three types of cooling.polymorphism / X-ray diffraction / differential scanning calorimetry / camel's milk * Corresponding author ( ): michel.ollivon@cep.u-psud.frArticle published by EDP Sciences and available at http://www.edpsciences.org/lait or http://dx

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“…The channels of the detectors are calibrated to express the XRDT data in the scattering vector q with q = 4π·sin (θ) / λ = 2π/d; q in angstrom -1 , θ in degrees is the angle of incidence of the X-ray wavelength, d in angstrom is the repetition distance between two planes. The calibration of the detectors was carried out at wide angles with high purity tristearin, which is characterized by short spacing of 4.59, 3.85 and 3.70 ± 0.01 Å at room temperature [29], complemented at small angles with silver behenate characterized with a long spacing of 58.380 ± 0.001 Å [5], as previously described [19].…”

Section: Xrdt/dsc Measurementsmentioning

confidence: 99%

Dromedary milk fat: thermal and structural properties 1. Crystalline forms obtained by slow cooling

Karray¹,

Lopez²,

Lesieur

et al. 2004

Lait

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-The thermal and structural behavior of anhydrous dromedary milk fat (ADMF) was studied by a technique that allowed simultaneous time-resolved synchrotron X-ray diffraction as a function of temperature (XRDT) and high sensitivity differential scanning calorimetry (DSC). As the camel probably represents the mammalian species best adapted to the hottest temperatures on earth as well as to harsh climatic conditions, the fatty acid composition of ADMF and its thermal properties are of special interest. In this paper, the first of a series, the crystalline organizations made by the triacylglycerols (TG) of ADMF during a slow cooling rate at |dT/dt| = 0.1 °C·min -1 are addressed. The crystalline form obtained from about 29.5 °C corresponds to a lamellar structure with a double-chain length longitudinal organization of the TG molecules (2L = 42.3 Å) associated with a β' lateral packing of the chains. The crystallization range which spreads over about 75-80°C, is similar to that observed for bovine milk fat, although the final melting temperature is higher by about 5-8 °C. DSC scans revealed the existence of up to 6 exotherms on slow cooling. A similar complex behavior was also observed on heating. PEAKFIT analysis of the XRDT individual patterns and their evolutions observed at small angles also showed the existence of additional molecular packings. However, XRDT analysis was unable to resolve individual structures. A possible epitaxy phenomenon during crystallization is discussed. Polymorphism / X-ray diffraction / differential scanning calorimetry / solid fat content / epitaxyRésumé -Propriétés thermiques et structurales de la matière grasse de lait de dromadaire. 1. Formes cristallines obtenues lors d'un refroidissement lent. Les propriétés thermiques et structurales de la matière grasse anhydre extraite du lait de dromadaire (ADMF) ont été étudiées par une nouvelle technique qui permet des mesures simultanées, sur un même échantillon, des signaux de microcalorimétrie différentielle à balayage (DSC) et de diffraction des rayons X en fonction du temps et de la température. L'étude des propriétés thermiques de la matière grasse du lait de chamelle, en relation avec sa composition, revêt un intérêt particulier si l'on considère les conditions

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Preparation of silver behenate coatings to provide low- to mid-angle diffraction calibration

Abstract: A method for the preparation of a well aligned silver behenate sample is described. Multiple (0 0 l) diffraction peaks, (0 0 1) to (0 0 48), are easily observed using a conventional laboratory X‐ray diffraction instrument.

Cited by 70 publications

References 5 publications

Analysis of engineered nanomaterials in complex matrices (environment and biota): General considerations and conceptual case studies

Analysis of engineered nanomaterials in complex matrices (environment and biota): General considerations and conceptual case studies

Dromedary milk fat: thermal and structural properties 2. Influence of cooling rate

Dromedary milk fat: thermal and structural properties 1. Crystalline forms obtained by slow cooling

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