Sn-Sb and Sn-Bi alloys as anode materials for lithium-ion batteries

Sn/SnSb, Sn/Bi, and Sn/SnSb/Bi multi-phase materials were synthesised via reduction of cationic precursors with NaBH₄ and with Zn, and were tested for their suitability as anode materials for Li-ion batteries by galvanostatic cycling. The rapid reduction with NaBH₄ yielded the finer materials with the better cycling stabilities, whereas the reduction with Zn yielded the purer materials with the lower irreversible capacities in the first cycle. Reversible capacities of ∼ 600 mAh g⁻¹, ∼ 350 – 400 mAh g⁻¹, and ∼ 500 mAh g⁻¹ were obtained for Sn/SnSb, Sn/Bi, and Sn/SnSb/Bi, respectively. The cycling stability of the materials decreased in the order Sn/SnSb>Sn/SnSb/Bi>Sn/Bi, which is in part attributed to the presence / absence of intermetallic phases which undergo phase-separation during lithiation. Paper presented at the 8th EuroConference on Ionics, Carvoeiro, Algarve, Portugal, Sept. 16–22, 2001.     

A bandstructure approach to the calculation of density correlation functions with application to Vanadium

We discuss how to use KKR bandstructure to evaluate the density-density correlation function in DFA (density functional) — RPA approximation without introducing adjustable parameters. We stress the importance to determine the dielectric function to a high degree of accuracy in the high frequency range to guarantee the fulfillment of the f-sum rule. Results for Vanadium as a typical example of a transition metal are presented and compared to experiment.     

In-trees and plane embeddings of outerplanar graphs

A notion of anin-tree is introduced. It is then used to characterize and count plane embeddings of outerplanar graphs. In-trees have also been applied in the study of independent vertex covers of faces in outerplanar graphs.This research was partially supported by the grant RP.I.09, from the Institute of Informatics, University of Warsaw. Hospitality of the Institute of Datalogy, University of Copenhagen where this research has been completed is gratefully acknowledged.     

Anticancer agent development: X-ray crystal structure and keto-enol tautomerism of dimethyl 1-hydroxy-6,7-methylenedioxy-4-(3′,4′,5′-trimethoxyphenyl-trans-3,4-dihydronaphthalene-2,3-dicarboxylate

Structural and conformational information obtained from the crystal structure and solution¹H nmr investigations of the title compound are compared. The 4-aryltetralone, C₂₄H₂₄O₁₀, crystallizes as a chloroform solvate in the monoclinic space group, P2₁/n, witha=12.519(4),b=17.938(6),c=12.534(9)Å,=111.90(5)°, and D_calc=1.51 g cm^–3 forZ=4. The data for this compound were collected at –150°C. Least-squares refinement of 2796 observed [F _o5(F _o)] reflections led to the final agreement index ofR=0.062. A threefold static disorder was observed for one of the carboxyl groups. The second carboxyl group participates in an intramolecular hydrogen bond and is thus ordered. The¹H nmr spectrum revealed the title compound to exist as a keto-enol tautomeric mixture in solution. Vicinal hydrogen coupling constant analysis proved reliable in ascertaining B-ring stereochemistry of 2,3-disubstituted-4-aryltetralones.     

Gas-Chromatographie

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Milch

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Nitrat

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