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121.
R. Geetha A. Torikai S. Yashida S. Nagaya K. Fueki 《Journal of polymer science. Part A, Polymer chemistry》1989,27(5):1653-1663
The fourth type of polyethylene—very low density polyethylene (VLDPE)—has been developed very recently. VLDPE is a copolymer of ethylene and 1-butene. The radiation and photo degradation of VLDPE was studied using gel, FT-IR, and UV spectral measurements. Mechanical tests were also done; the rate of gel and carbonyl formation was high. End methyl ? CH3 group was found to increase in the case of radiation degradation. The initial modulus was very low indicating the rubbery nature in the copolymer. VLDPE was found to be highly resistant to radiation-induced degradation than linear low density polyethylene. VLDPE is highly susceptible to thermal effects. 相似文献
122.
123.
A generalization of the QR algorithm proposed by Francis [2] for square matrices is introduced for the singular values decomposition of arbitrary rectangular matrices. Geometrically the algorithm means the subsequent orthogonalization of the image of orthonormal bases produced in the course of the iteration. Our purpose is to show how to get a series of lower triangular matrices by alternate orthogonal-upper triangular decompositions in different dimensions and to prove the convergence of this series. 相似文献
124.
The thermoelectric power (TEP) of cerium has been measured up to 6 GPa. The results have been interpreted using the theories developed by Blandin et. al. and Hirst. 相似文献
125.
Abe F Akimoto H Akopian A Albrow MG Amendolia SR Amidei D Antos J Anway-Wiese C Aota S Apollinari G Arisawa T Asakawa T Ashmanskas W Atac M Azfar F Azzi-Bacchetta P Bacchetta N Badgett W Bagdasarov S Bailey MW Bao J de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Barzi E Bauer G Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Benjamin D Benlloch J Bensinger J Benton D Beretvas A Berge JP Berryhill J Bertolucci S Bevensee B Bhatti A Biery K Binkley M Bisello D Blair RE 《Physical review letters》1996,77(27):5336-5341
126.
Gaspar LJ Baskar G Reddy BS Ranganathan R Peric M 《Langmuir : the ACS journal of surfaces and colloids》2004,20(21):9029-9035
The cosurfactant activity of N-glycinylmaleamic acid (NGMA) in sodium dodecyl sulfate (SDS) micelles has been demonstrated. The complementary techniques of electron spin resonance (ESR) and fluorescence spectroscopy have been used to draw information on hydration index (H), microviscosity (eta), and aggregation number (N) of micellar assemblies. The estimate of the critical micelle concentration of SDS in the presence of NGMA suggests a synergistic effect of NGMA. The enhanced solubilization of butyl propionate in the presence of NGMA in SDS micelles is explained on the basis of availability of larger interfacial area calculated from a simple spherical geometric model, combined with a low hydrophilicity index as estimated from ESR. Thus, addition of NGMA contributes to an increase of about 50% in ratio of area of polar shell (AP)/volume of hydration (Vh) ratio. The decrease in H accompanied by a decrease in eta with the incorporation of butyl propionate probably arises from solubilization of a butyl component inside the core with the adsorption of propionate ester on the interface. 相似文献
127.
Summary A sensitive spray reagent for visualization in TLC of phosphate esters is obtained by deglobulinization and purification of horse serum. The spots, produced in the areas where the phosphate esters inhibit the choline esterase of the serum, are clear and sharp-edged against a dark background. The reagent can be prepared in bulk quantities, is not expensive and can be stored at 4°C without deterioration for a long time (6–12 months). 相似文献
128.
Geetha Ramakrishnan M. B. V. L. N. Swamy P. Sambasiva Rao S. Subramanian 《Journal of Chemical Sciences》1991,103(5):613-619
Single crystal EPR spectra of a natural mineral, apophyllite, containing VO(II) ion as an impurity have been investigated.
The EPR spectra of the mineral, as obtained, was complex in nature, but was simplified by annealing the crystals at 490 K.
The EPR parameters of the VO(II) species in the annealed crystal,g
∥ = 1.924 (2);g
⊥ = 1.983 (2);A
∥ = 18.35 (5); andA
⊥ = 7.24 (5)mT, are very close to a typical VO(II) impurity. Theoretically calculated line positions, using second-order hyperfine
terms in the spin Hamiltonian with an axially symmetricg andA tensor values, agreed very well with the experimental ones. The EPR analysis of the annealed crystal has further revealed
that the most preferred location of the VO(II) impurity is a substitutional Ca(II) site. The calculated bonding parameters
and admixture coefficients indicate a fair amount of covalent bonding in the complex. 相似文献
129.
Thiagarajan G Shirao E Ando K Inoue A Balasubramanian D 《Photochemistry and photobiology》2002,76(3):368-372
We have been able to identify a blue fluorophore from the low-molecular weight soluble fraction of human adult nondiabetic brunescent cataract lenses as xanthurenic acid 8-O-beta-D-glucoside (XA8OG) (excitation = 338 nm and emission = 440 nm). To determine the role of this fluorophore in the lens, we have examined its photophysical and photodynamic properties. We found XA8OG to have a fluorescence quantum yield (phi) of 0.22 and a major emission lifetime of 12 ns. We found it to be a UVA-region sensitizer, capable of efficiently generating singlet oxygen species but little of superoxide. We also demonstrated that XA8OG oxidizes proteins when irradiated with UVA light, causing photodynamic covalent chemical damage to proteins. Its accumulation in the aging human lens (and the attendant decrease of its precursor O-beta-D-glucoside of 3-hydroxykynurenine) can, thus, add to the oxidative burden on the system. XA8OG, thus, appears to be an endogenous chromophore in the lens, which can act as a cataractogenic agent. 相似文献
130.
R. Malathi S. S. Rajan Geetha Gopalakrishnan G. Suresh 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(11):o681-o682
The title compound, methyl (2aS,3R,5R,5aS,6S,6aS,8R,9aS,10aR,10bR,10cS)‐8‐(3‐furyl)‐2a,4,5,5a,6,6a,8,9,9a,10a,10b,10c‐dodecahydro‐3‐hydroxy‐2a,5a,6a,7‐tetramethyl‐5‐(3‐methylbut‐2‐enoyloxy)‐2H,3H‐cyclopenta[4′,5′]furo[2′,3′:6,5]benzo[cd]isobenzofuran‐6‐acetate, C32H42O8, was isolated from uncrushed green leaves of Azadirachta indica A. Juss (neem) and has been found to possess antifeedant activity against Spodptera litura. The conformations of the functional groups are similar to those of 3‐desacetylsalannin, which was isolated from neem kernels. The molecules are linked into chains by intermolecular O—H?O hydrogen bonds. 相似文献