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221.
T. Othman Corresponding author Z. Hammami A. Gharbi H. T. Nguyen 《Liquid crystals》2013,40(8):1061-1067
We have investigated the viscoelastic behaviour exhibited by chiral smectic C* phases in homeotropic orientation. For an appropriate scattering geometry and using the light scattering technique, the orientational diffusivities associated with the Goldsone mode in ferro- and antiferroelectric phases of C11thiobenzoate and C8tolane compounds have been measured. (SmCA*) is about 100 times weaker than (SmC*). This divergence may be largely attributed to the mode of the molecular arrangement in ferro- and antiferroelectric phases, in spite of the same helical structure observed in the two phases. 相似文献
222.
A new model of the equations of generalized thermovisco-elasticity for a thermally, isotropic and electrically conducting half-space solid whose surface is subjected to a thermal shock is given. The formulation is applied to the generalized thermoelasticity based on the Green and Lindsay (GL) theory under the effect of rotation, where there is an initial magnetic field parallel to the plane boundary of the half-space. The medium is deformed because of thermal shock and due to the application of the magnetic field, it results an induced magnetic and electric fields in the medium. The normal mode analysis is used to obtain the expressions for the variables considered. The distributions of temperature, displacement, stress, induced magnetic and electric fields are represented graphically. Comparisons are made with the results predicted by the coupled theory (CD) in the presence and absence of rotation. 相似文献
223.
224.
Using a light scattering technique at a fixed temperature, we have investigated viscoelastic behaviour exhibited by the ferroelectric smectic phase (SmC*) of C8tolane in a homeotropic orientation. Experiments were performed in backward and forward scattering geometries that allowed us to deduce separately orientational diffusivities k3/η and k+/η corresponding to the Goldstone mode. The k3/η value measured in the SmC* phase is about 100 times higher than in the SmCA* phase exhibited by the same liquid crystal compound. The factor 100 may be attributed in great part to the molecular arrangement mode in adjacent smectic layers. However k+/η measured in the SmC* phase is in the same order of magnitude as those measured previously in SmCA* phases. 相似文献
225.
Weina Jiang Wei Zhou Raymie Othman Hajime Uchida Ryuichi Watanabe Toshiyuki Suzuki 《Natural product research》2018,32(1):97-104
A new malyngamide (1) was isolated along with seven known compounds (2–8) from the marine cyanobacterium Moorea producens collected in Hawaii. Compound 1 represented the first reported malyngamide with a hydroxy moiety at C-7 of the characteristic fatty acid portion of the compound. Compound 1 showed cytotoxicity against L1210 cell line at an IC50 value of 2.9 mM and lethal toxicity against the shrimp Palaemon paucidens at a LD100 value of 33.3 mg/kg. The bioactivity of compound 1 was approximately 10–100 times weaker than those of isomalyngamides A and B (3, 4). These results indicated that the methoxy group at C-7 of the fatty acid section confers a degree of bioactivity in malyngamides. 相似文献
226.
Differential scanning calorimetry (DSC) under non-isothermal conditions is used to study the crystallization kinetics of Sb14As29Se52Te5 chalcogenide glass. In addition, two approaches are used to analyze the dependence of glass transition temperature (Tg) on the heating rate (α). One is empirical linear relationship between (Tg) and ln(α). The second approach is the use of straight line vs. 1/Tg for the evaluation of the activation energy for glass transition. The phases at which the alloy crystallizes after the thermal treatment have been identified by using X-ray diffraction. The diffractogram of the transformed material shows the presence of some crystallites of As, Te, AsSb, As2Se3, Sb2Se3 and AsSe.5Te.5 in the residual amorphous matrix. 相似文献
227.
A. Kovacs L. Wojnarovits M. Baranyai A. Moussa I. Othman W. L. McLaughlin 《Radiation Physics and Chemistry》1999,55(5-6):795-798
The radiolytic reactions of the ditetrazolium salt nitro blue tetrazolium chloride (NBTCl2) were studied by pulse radiolysis technique in aqueous solution under reducing and oxidising conditions with the aim of potential dosimetry application. Under reducing conditions the fast formation of the tetrazolinyl radical is observed that is followed by the appearance of monoformazan (MF+), i.e. one of the tetrazolium rings is reduced to formazan. The formation of the water-insoluble diformazan, i.e. the result of the second reduction step was not observed in pulse radiolysis. Formazan formation was not found under oxidative conditions. 相似文献
228.
229.
M. Asma A. Bansal W. A. M. Othman B. R. Wong A. Biswas 《Physics of Wave Phenomena》2018,26(4):312-316
Here, optical soliton perturbation with quadratic-cubic nonlinearity has been discussed by applying Lie symmetry and group invariants. The perturbation terms include third and fourth order dispersions in addition to self-steepening, intermodal dispersion and higher order dispersion effects. Using presented algorithms, Bright and dark soliton solutions are revealed. 相似文献
230.
Robert Walsh Othman Nasir Nicola Calder Sean Sterling John Avis 《Transport in Porous Media》2018,123(3):501-519
This paper describes modeling studies assessing the feasibility of increasing the maximum storage pressure in several underground natural gas storage reservoirs. This required an assessment of the potential for gas transport in the caprock and the geomechanical response to pressure change in the storage reservoir. To solve this problem in an efficient manner, two-phase flow (TOUGH2) and geomechanical (FLAC3D) models were combined in series. The TOUGH2 model was calibrated to fit pressure data collected on-site, from both the reservoir and caprock. The mechanical response of the caprock to increased storage pressure was modeled using FLAC3D, allowing assessment of the induced stresses in formations surrounding the reservoirs. We focused on two sites. In the first, field data were obtained from a deep borehole above the gas reservoir, which provided indirect observations of the geomechanical response of the caprock to pressure changes in the reservoir. In the second, open boreholes intersecting two thin caprock units immediately above the reservoir allowed gas flow to a shallower unit, significantly impacting the modeled fracture gradient. 相似文献