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In this paper, we show that the monotone iterative technique produces two monotone sequences that converge uniformly to extremal solutions for the periodic delay ?-Laplace equation. Moreover, we obtain optimal existence conditions with upper and lower solutions in the reverse order. 相似文献
357.
Daqing Jiang Xiaojie Xu Donal O’Regan Ravi P. Agarwal 《Czechoslovak Mathematical Journal》2005,55(2):483-498
In this paper we present some new existence results for singular positone and semipositone boundary value problems of second order delay differential equations. Throughout our nonlinearity may be singular in its dependent variable. 相似文献
358.
New fixed point results are presented forU
c
k
(X, X) maps in extension type spaces. 相似文献
359.
Fabian M. Schuett Derek Esau K. Liam Varvaris Shelly Gelman Jonas Bjrk Johanna Rosen Gregory Jerkiewicz Timo Jacob 《Angewandte Chemie (International ed. in English)》2020,59(32):13246-13252
The growth of noble‐metal single crystals via the flame fusion method was developed in the 1980s. Since then, there have been no major advancements to the technique until the recent development of the controlled‐atmosphere flame fusion (CAFF) method to grow non‐noble Ni single crystals. Herein, we demonstrate the generality of this method with the first preparation of fcc Cu as well as the first hcp and bcc single crystals of Co and Fe, respectively. The high quality of the single crystals was verified using scanning electron microscopy and Laue X‐ray backscattering. Based on Wulff constructions, the equilibrium shapes of the single‐crystal particles were studied, confirming the symmetry of the fcc, hcp, and bcc single‐crystal lattices. The low cost of the CAFF method makes all kinds of high‐quality non‐noble single crystals independent of their lattice accessible for use in electrocatalysis, electrochemistry, surface science, and materials science. 相似文献
360.
A simple method was developed to separate Pu and Am using single column extraction chromatography employing N,N,N′,N′-tetra-n-octyldiglycolamide (DGA) resin. Isotope dilution measurements of Am and Pu were performed using accelerator mass spectrometry (AMS) and alpha spectrometry. For maximum adsorption Pu was stabilized in the tetra valent oxidation state in 8 M HNO3 with 0.05 M NaNO2 before loading the sample onto the resin. Am(III) was adsorbed also onto the resin from concentrated HNO3, and desorbed with 0.1 M HCl while keeping the Pu adsorbed. The on-column reduction of Pu(IV) to Pu(III) with 0.02 M TiCl3 facilitated the complete desorption of Pu. Interferences (e.g. Ca2+, Fe3+) were washed off from the resin bed with excess HNO3. Using NdF3, micro-precipitates of the separated isotopes were prepared for analysis by both AMS and alpha spectrometry. The recovery was 97.7 ± 5.3% and 95.5 ± 4.6% for 241Am and 242Pu respectively in reagents without a matrix. The recoveries of the same isotopes were 99.1 ± 6.0 and 96.8 ± 5.3% respectively in garden soil. The robustness of the method was validated using certified reference materials (IAEA 384 and IAEA 385). The measurements agree with the certified values over a range of about 1–100 Bq kg−1. The single column separation of Pu and Am saves reagents, separation time, and cost. 相似文献