15,961 research outputs found
The Gaussian curvature of the oil-water interface in an isometric bicontinuous microemulsion
No full textSmall-angle neutron scattering (SANS) measurements are made on a three-component isometric (equal volume fractions of water and oil) microemulsion system, composed of AOT/water (0.4% NaCl)/D-octane, in the one-phase channel near the three-phase region at and around the hydrophile-lipophile balance temperature. A previous SANS contrast variation experiment indicated that the microstructure of this type of isometric microemulsion is bicontinuous in water and oil with the surfactant film at the interface having a zero mean curvature. We analyze SANS data taken with an oil-water contrast in terms of a modified Berk's random wave model. We choose a spectral function which is an inverse sixth-order polynomial, with three parameters a, b and c, as introduced by Lee and Chen earlier. This three-parameter spectral function is then used in conjunction with Cahn's clipping scheme to obtain the Debye correlation function appropriate for the microemulsion system. The model analysis results in good agreement with the intensity data in an absolute scale. We then use the three parameters. so obtained to calculate the average Gaussian curvature of the interface. We discuss the variation of the average Gaussian curvature as a function of the surfactant volume fraction and its implication on the degree of local order of the bicontinuous structure. We also show a 3-D reconstructed morphology of the most disordered microemulsion
Matsumuramata Xing & Chen, 2014, nom. nov.
No full textGenus Matsumuramata nom. nov. Numata Matsumura, 1935: 139 (Hemiptera: Fulgoromorpha: Delphacidae). Preoccupied by Numata Busck, 1906: 724 (Lepidoptera: Gelechioidea: Gelechiidae). Type species: Stenocranus sacchari Matsumura, 1910 Etymology. The generic name is dedicated to Prof. Shōnen Matsumura who is the author of the preexisting generic name Numata. Gender: feminine.Published as part of Xing, Ji-Chun & Chen, Xiang-Sheng, 2014, Nomenclatural changes for the genus Discophorellus Tsaur & Hsu, 1991 and new replacement name for Numata Matsumura, 1935 (Hemiptera: Fulgoromorpha), pp. 149-150 in Zootaxa 3856 (1) on page 150, DOI: 10.11646/zootaxa.3856.1.8, http://zenodo.org/record/492985
Measurements of the curvatures of random surfaces by scattering experiments: the case of bicontinuous microemulsions
No full textA small-angle neutron scattering (SANS) study is made on a three-component isometric (equal volume fractions of water and oil) ionic microemulsion system, composed of AOT/brine/decane. SANS measurements are made as a function of volume fraction of surfactant within the one-phase channel next to the three-phase region at the hydrophile-lipophile balance (HLB) salinity and at a constant temperature. A previous SANS contrast variation experiment indicated that the microstructure of this type of isometric microemulsion at and around the HLB temperature is bicontinuous in water and oil, with a mono-layer of surfactant film situated at the oil-water interface, having zero mean curvature. We analyze SANS data taken with an oil-water contrast in terms of a modified Berk random wave model. We choose a spectral function which is an inverse 8-th order polynomial in wave number k, containing three length scales 1/a, 1/b, and 1/c. The spectral function has finite second and fourth moments. This three-parameter spectral function is then used in conjunction with Cahn's clipping scheme to obtain the Debye correlation function for the micro-phase-separated microemulsions. The model shows good agreement with the intensity data;in an absolute scale. We then use the three parameters so obtained to calculate the average square mean curvature and the average Gaussian curvature of the interface. We determine the variation of these curvatures and the underlying spectral functions as a function of the surfactant volume fraction and discuss their implication on the degree of local order of the bicontinuous structure. We also show 3-d morphologies of two of the microemulsions generated by this model
Microstructure of Epitaxial YBBa2Cu3O7 Superconducting Films Grown by New Liquid-Gas-Solidification Technique
No full textBladder instillation of Escherichia coli lipopolysaccharide alters the muscle contractions in rat urinary bladder via a protein kinase C-related pathway.
No full textMolecular genetic evidence supporting a novel human hepatocellular carcinoma tumor suppressor locus at 13q 12.11
No full textMeasurement and Interpretation of Curvatures of the Oil–Water Interface in Isometric Bicontinuous Microemulsions
No full textA small-angle neutron scattering (SANS) study was carried out on a three-component isometric (equal volume fractions of water and oil) ionic microemulsion system, composed of AOT/brine/decane [AOT= surfactant sodium bis(ethylhexylsufo)succinate]. SANS measurements were made as a function of volume fraction of surfactant within the one-phase channel at the hydrophile–lipophile balance (HLB) salinity and at a constant temperature. We analyzed SANS data taken with oil–water contrast in terms of a modified Berk random wave model. The good agreement of the model with SANS intensity requires a proper form of spectral function. We chose a spectral function which is an inverse eighth-order polynomial in wave number k, containing three length scales 1/a, 1/b and 1/c. The spectral function has finite second and fourth moments. The model shows good agreement with the intensity data in an absolute scale. The three parameters so obtained were then used to calculate the average square mean curvature and the average Gaussian curvature of the interface. The variation of these curvatures and the underlying spectral functions as a function of the surfactant volume fraction were determined and their implications for the degree of local order of the bicontinuous structure are discussed.</jats:p
Mesoscopic scale structures in self-organized surfactant solutions determined by small-angle neutron scattering
No full textA novel procedure for SANS data analysis is described which enables one to use the fitted parameters to compute the average mean. Gaussian and square mean curvatures of the interface in systems which show a micro-phase-separated bicontinuous structure. This procedure also leads to a 3-D reconstruction of the connected internal interface which allows one to visualize the mesoscopic scale morphology of the material. The method has been successfully applied to Various bicontinuous structures such as microemulsions made of surfactant, water and oil, porous silica glasses and phase-separated homopolymer blends. In this lecture, we show examples of analyses of SANS;lata taken from one-phase bicontinuous microemulsions at the hydrophile-lipophile-balance temperature and a light scattering intensity taken from a symmetric micro-phase-separated polymer blend at the late stage of spinodal decomposition. (C) 1998 Elsevier Science Limited. All rights reserved
Intramolecular Diels-Alder cycloadditions of fulvenes. Application to the kigelinol, neoamphilectane, and kempane skeletons
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