排序方式: 共有48条查询结果,搜索用时 15 毫秒
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Dhananjai Pandey V. S. Tiwari A. K. Singh V. K. Wadhawan M. S. Somayazulu 《Phase Transitions》2013,86(2-3):165-202
Crystal structures and structural inhomogeneities observed in YBa2Cu3O7-y are reviewed. It is brought out that a proper understanding of the nature of the structural inhomogeneities is essential for exploiting the technological potential of this material. The need for an adequate characterization of specimens used for experiments is emphasized. Practical implications of the ferroelastic nature of the material are discussed. 相似文献
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Neel Sisodia Monica Miranda Kay L. McGuinness Jay D. Wadhawan Nathan S. Lawrence 《Electroanalysis》2021,33(3):559-562
This work presents the electrochemical response of a 2-(methylthio)phenol glassy carbon based electrode for a promising voltammetric pH sensor in both buffered and low-buffered solutions. Electropolymerization of the redox species was performed with the resulting polymer presenting a Nernstian response in buffered media, with a sensitivity of 51 mV/pH unit. The effectiveness of the sulfhydryl bond to facilitate proton transfer from the bulk solution to the phenol molecules has been confirmed, providing an accurate pH measurement of 8.28 in sea water media, compared to that measured with a calibrated glass pH probe of 8.30. 相似文献
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V K Wadhawan 《Pramana》1974,3(6):370-376
A mathematical analysis has been made of the combined effect of crystal and collimator misalignments on Bragg angles measured from zero-layer Weissenberg photographs. The results obtained here have been compared with those available for Bond’s method of measuring Bragg angles with diffractometers. The comparison shows that, for a given amount of crystal and collimator misalignments, Bond’s method and the 2 θ-method do not give identical results for small and intermediate Bragg angles. 相似文献
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A point-defect model of structural phase transitions in YBa2Cu3O6 + x is proposed. The model treats the basal-plane oxygen atoms as point defects. The treatment parallels the work of Alefeld and coworkers on ferroelasticity due to hydrogen in metals. The model predicts that the tetragonal-to-orthorhombic phase transition should be accompanied by precipitation into regions of high and low oxygen density, as well as high and low oxygen ordering. This is in agreement with experiment, as well as with the predictions of Khachaturyan's concentration-wave model. A new feature of the present model is the prediction of two characteristic temperatures related, respectively, to Snoek-type and Gorsky-type diffusive relaxations. Practical implications of the high diffusivity of the basal-plane oxygens include the easy fabricability of a bicrystal of Y-Ba-Cu-O such that the two components of the bicrystal are rotated by 90° with respect to each other, and are separated by a non-superconducting layer. Such a bicrystal can find applications as a Josephson-tunneling device. 相似文献
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Yuehua Dou Stephen Haswell John Greenman Jay Wadhawan 《Electrochemistry communications》2009,11(10):1976-1981
The detection of hydrogen peroxide is detailed using horseradish peroxidase and anthraquinone. Both species are immobilized on a glassy carbon electrode substrate. This dual immobilization gives rise to lower detection limits compared with the situation when either of the species is immobilized. Detection limits of 40 nM are reported within physiologically-relevant media. 相似文献
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J. K. Brooks Kazuyuki Saitô JD Maitland Wright 《Rendiconti del Circolo Matematico di Palermo》2003,52(1):5-14
LetA be aC*-algebra with second dualA″. Let (φ
n)(n=1,...) be a sequence in the dual ofA such that limφ
n(a) exists for eacha εA. In general, this does not imply that limφ
n(x) exists for eachx εA″. But if limφ
n(p) exists whenever p is the range projection of a positive self-adjoint element of the unit ball ofA, then it is shown that limφ
n(x) does exist for eachx inA″. This is a non-commutative generalisation of a celebrated theorem of Dieudonné. A new proof of Dieudonné’s theorem, for
positive measures, is given here. The proof of the main result makes use of Dieudonné’s original theorem. 相似文献