217 research outputs found
Corrigendum: Conjugated microporous poly(aryleneethynylene) networks
No full textThis corrigendum relates to: Conjugated Microporous Poly(aryleneethynylene) Networks, Jia-Xing Jiang, Fabing Su, Abbie Trewin, Colin D. Wood, Neil L. Campbell, Hongjun Niu, Calum Dickinson, Alexey Y. Ganin, Matthew J. Rosseinsky, Yaroslav Z. Khimyak, Andrew I. Cooper, Volume 46, Issue 45, Angewandte Chemie International Edition, pages 8574-8578. First Published online: September 26, 2007. There was a small error in the second sentence on page 8576 of this Communication. This sentence should read: “The ratio of intensities of acetylene to aromatic peaks was calculated using variable-contact-time 1H–13C CP/MAS NMR spectra with the following results: CMP-1 0.27 (expected value 0.40); CMP-2 0.18 (expected value 0.25); CMP-3 0.10 (expected value 0.18).” The authors apologize for this error and wish to note that none of the interpretations in the paper are affected by this change
Cryptanalysis and designing chaos-based irreversible and parallel key expansion module over Galois field
No full textFrom the security criteria of irreversibility, parallelizability and
independence, we cryptanalyzed the key expansion modules of candidate block
ciphers of AES, the results revealed that there exist some weaknesses inside,
which may be explored by the attacker. Hence, we designed a more secure key
expansion module that the round-key can satisfy three criteria above. First, we
constructed a non-degenerate 2D chaotic map (2D-{\pi}eCM) with ergodicity in
phase space and sufficient large chaotic range. Then based on 2D-{\pi}eCM and
polynomial multiplication over Galois field, we designed an irreversible key
expansion module, which could transform the initial key of arbitrary length to
desired number of independent round keys in parallel. Security and statistical
results demonstrated the flexible and effectiveness of the proposed key
expansion module.Comment: Technique proble
Theoretical study on spatial property of parametric fluorescence in a type I BBO crystal
No full textEvolution of Magnetic Symmetry through the BiFeO3–Ca2Fe4/3W2/3O6Phase Diagram
No full textPerovskites offer vast flexibility in tuning subtle distortions in their structures through their innate ability to host a wide range of compositional combinations. Minor changes in composition can dramatically influence the properties observed through structural distortions such as octahedral tilting. In addition to understanding their properties, in magnetic materials, the magnetic structure is also tied to the nuclear structural distortions and can have more complex behavior with changing composition. In this work we report on the magnetic properties, and nuclear and magnetic structures of the solid solution (1 – x)BiFeO3– (x/2)Ca2Fe4/3W2/3O6. With the exception of BiFeO3, all samples show a weak ferromagnetic behavior arising from spin canting. We find that despite only one structural phase transition occurring from R3c to Pnma in this solid solution, the magnetic phase diagram is far more complex, with four distinct magnetic phases occurring in the compositional range 0.1 < x < 1. Using a combination of neutron and X-ray diffraction, we find that a crossover between long and short Fe–O bond lengths and divergence of Fe–O–Fe bond angles with composition drive the changes in magnetic structure and can be correlated to the resulting magnetic properties
Adsorption of low cross-linking density hydrogel OMMT/acid hydrolysis lignin grafted polyacrylic acid for Cd (II)
No full textThe numerical simulation on swelling factor and extraction rate of a tight crude oil and SC-CO2 system
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