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51.
52.
A metal-free acetate shift of 3-acetoxy ynamides to access α-iodo, bromo, and chloro acrylamides/acrylimides under very mild conditions is demonstrated. The inherent alkyne activation of ynamides is sufficient to ensure the α-halo acrylamides/acrylimides in high yields without the addition of a catalyst. In all cases high Z-stereoselectivity is observed. 相似文献
53.
54.
J. Haglund 《Advances in Mathematics》2011,227(5):2092
A special case of Haiman?s identity [M. Haiman, Vanishing theorems and character formulas for the Hilbert scheme of points in the plane, Invent. Math. 149 (2002) 371–407] for the character of the quotient ring of diagonal coinvariants under the diagonal action of the symmetric group yields a formula for the bigraded Hilbert series as a sum of rational functions in q,t. In this paper we show how a summation identity of Garsia and Zabrocki for Macdonald polynomial Pieri coefficients can be used to transform Haiman?s formula for the Hilbert series into an explicit polynomial in q,t with integer coefficients. We also provide an equivalent formula for the Hilbert series as the constant term in a multivariate Laurent series. 相似文献
55.
Professor Stig Stenholm 《Contemporary Physics》2013,54(6):537-539
The paper begins with a general discussion of the properties of elastic liquids and with the use of models, consisting of springs and dashpots, to describe their behaviour. Next the linear and non-linear behaviour of these liquids are described together with some of the more striking observed properties. Experimental measurements are next discussed. The paper ends with a brief account of theoretical work that has been done on elastic liquids. 相似文献
56.
Electron-beam deposition of vanadium dioxide thin films 总被引:1,自引:0,他引:1
R. E. Marvel K. Appavoo B. K. Choi J. Nag R. F. Haglund Jr. 《Applied Physics A: Materials Science & Processing》2013,111(3):975-981
Developing a reliable and efficient fabrication method for phase-transition thin-film technology is critical for electronic and photonic applications. We demonstrate a novel method for fabricating polycrystalline, switchable vanadium dioxide thin films on glass and silicon substrates and show that the optical switching contrast is not strongly affected by post-processing annealing times. The method relies on electron-beam evaporation of a nominally stoichiometric powder, followed by fast annealing. As a result of the short annealing procedure we demonstrate that films deposited on silicon substrates appear to be smoother, in comparison to pulsed laser deposition and sputtering. However, optical performance of e-beam evaporated film on silicon is affected by annealing time, in contrast to glass. 相似文献
57.
Stig Stenholm 《Optics Communications》2006,264(2):385-392
I consider the general functions depending on the quantum state represented by a two-level density matrix. Quantities of relevance are state distance and informations measures, i.e. entropies. I introduce a new complex representation of such functions. Utilizing the geometric interpretation of complex mappings, I summarize several properties of such transformations of the state. In particular these results are used to suggest several possible applications to physical questions. These are tentative only, but they indicate the physical relevance of the mathematical results presented. 相似文献
58.
Bjrn Fritzell Britta Hammarberg Helge Schiratzki Stig Haglund Evert Knutsson Anders Mrtensson 《Journal of voice》1993,7(2)
From a total of 43 adductor spasmodic patients over a 10-year period, 11 underwent resection of a portion of the recurrent laryngeal nerve on one side. The initial results were excellent but a varying degree of recurrence took place in 8 patients. In 4, a reoperation was done. At the final follow-up, 2–8 years after the primary operation, 4 patients were no longer suffering from spasmodic dysphonia, another 5 were better off than before surgery, and 1 remained unchanged. Only 1 was worse off. Electromyographic findings indicated that the recurrence of symptoms was due to regeneration of the nerve fibers. 相似文献
59.
Cadmium, copper, iron, lead, nickel and zinc are determined. The dithiocarbamate complexes of the metals are extracted into Freon-TF and back-extracted into dilute nitric acid solution. Portions of the back-extracts are injected into a graphite furnace. The method gives complete separation from the matrix irrespective of salinity. It is therefore useful throughout the full salinity range of an estuary, 0–35‰.The effect of high iron concentrations on the extraction is eliminated by using a mixed acetate buffercomplexing agent solution. 相似文献
60.
Stig Skelboe 《BIT Numerical Mathematics》1992,32(4):689-701
This paper presents a class of parallel numerical integration methods for stiff systems of ordinary differential equations which can be partitioned into loosely coupled sub-systems. The formulas are called decoupled backward differentiation formulas, and they are derived from the classical formulas by restricting the implicit part to the diagnonal sub-system. With one or several sub-systems allocated to each processor, information only has to be exchanged after completion of a step but not during the solution of the nonlinear algebraic equations.The main emphasis is on the formula of order 1, the decoupled implicit Euler formula. It is proved that this formula even for a wide range of multirate formulations has an asymptotic global error expansion permitting extrapolation. Besides, sufficient conditions for absolute stability are presented. 相似文献