The Virtual Geoscience Workbench,VGW： Open Source tools for discontinuous systems

In 1989 work began on merging finite and discrete elements. During 1990 algorithmic solutions for the new combined method were developed, together with a C-based implementation known as the Y code. In 2004 these developments and implementations were published as a textbook. Queen Mary University of London ~QMUL） and Imperial College are currently engaged in a research project to make Y codes in both 2D and 3D available in Open Source format and with mainly geoscience problems in mind. The result is a set of Open Source tools for Geoscience （VGW）, key components of which are summarised in this paper, together with illustrative range of simulation results. 2009 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.     

New evidence for a subshell gap at N=32

An 879.9(2) keV γ-ray transition has been identified following the β decay of ⁵⁸V and assigned as the 2⁺₁→0⁺₁ transition in ⁵⁸Cr₃₄. A peak in the energies of the first excited 2⁺ states for the even–even chromium isotopes is now evident at ⁵⁶Cr₃₂, providing empirical evidence for a significant subshell gap at N=32. The appearance of this neutron subshell closure for neutron-rich nuclides may be attributed to the diminished π1f_7/2–ν1f_5/2 monopole proton–neutron interaction as protons are removed from the 1f_7/2 single-particle orbital.     

Application of experimental design in a method for screening sediments for global determination of organic tin by electrothermal atomic absorption spectrometry (ETAAS)

An experimental design was developed to obtain a simple procedure for global determination of organic tin compounds in sediment. Sediment was extracted by a two-phase method and tin was determined in the organic extract by electrothermal atomic absorption spectrometry (ETAAS), with palladium as chemical modifier. A Plackett-Burman design for screening and a fractional central composite design (CCD) for optimizing were used for evaluation of the effects of several variables. The results showed that sediment mass, volume and concentration of extracting acid, pyrolysis and atomization temperatures, and modifier concentration affect the determination. Reference material PACS-2 was analyzed to evaluate the procedure. It was possible to extract 82% of the organotin content certified in the reference sediment. The limit of detection (LOD) was 0.08 microg g(-1) and the relative standard deviation was 4%. The method was applied to the analysis of estuarine superficial sediments from Gipuzkoa (Spain). The organotin content of these samples ranged from 0.7 to 7.7 microg g(-1), as tin, on a dry-weight basis.     

Reactions of 6‐aminopyrimidines with 2‐dimethylaminomethylenetetralone. Regiospecific Synthesis Of 5,6‐Dihydrobenzo [h]pyrimido [4,5‐b] quinolines

Benzo[h]pyrimido[4,5‐b]quinolines ( 3 ) have been synthesized via a regiospecific cyclocondensation reaction between 6‐aminopyrimidines ( 1 ) and 2‐dimethylaminomethylentetralone hydrochloride ( 2 ). The linear structure of the final compounds were determined by nmr measurements, especially by ¹H,¹H, ¹H,¹³C COSY and DEPT experiments.     

3,5-Bis(ferrocenylmethylene)-1-methyl-4-methylenepiperidine. Synthesis and some chemical properties

3,5-Bis(ferrocenylmethylene)-1-methyl-4-methylenepiperidine, a diferrocenyltriene with a fixeds-cisoid conformation of the exocyclic double bonds, was synthesized. On heating, this compound cyclodimerizes according to the [4+2]-cycloaddition scheme; it forms Diels-Alder adducts with azodicarboxylic and maleic acidN-phenylimides. The compound easily cyclodimerizes in the presence of acids by a proton cyclodimerization mechanism to give a spiro cyclodimer. The triene also adds a 3,5-bis(ferrocenylmethylene)-1,4-dimethyl-1-azonia-4-cyclohexyl salt to the terminal methylene group yielding linear and cyclic addition products. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 511–516, March, 2000.     

Fe2P2O7(H2O)2

The compound diiron diphosphate dihydrate, Fe₂P₂O₇(H₂O)₂, was synthesized hydro­thermally and crystallizes in the monoclinic space group P2₁/n. The compound has a somewhat open framework made up of edge‐sharing iron(II) octahedra that form chains connected by five bridging diphosphates. The remaining octahedral site of each iron is occupied by coordinated water. The H atoms of the water molecules all point into a common channel.     

Methyl 3‐para‐anisyl‐4‐(2‐hydroxy­benzoyl)­isoxazole‐5‐carboxyl­ate

The title compound, C₁₉H₁₅NO₆, contains a planar isoxazole ring. An intramolecular hydrogen bond is formed between the OH group attached to a phenyl ring and a carbonyl O atom.     

Methyl 2‐methyl‐6‐methyl­thio‐1,3‐dioxo‐4‐[(2,3,4,6‐tetra‐O‐acetyl‐β‐d‐gluco­pyran­osyl)­amino]‐2,3‐di­hydro‐1H‐pyrrolo­[3,4‐c]­pyridine‐7‐carboxyl­ate

The title compound, C₂₅H₂₉N₃O₁₃S, has peripheral acetyl and carbo­methoxy groups which show disorder. The absolute structure, although known from the starting materials, was confirmed by the analysis. There are no intermolecular hydrogen bonds. This structure is of importance because it elucidates the pathway for hetero‐Diels–Alder reactions between di­methyl acetyl­enedi­carboxyl­ate and 6‐amino­pyridin‐4(3H)‐one derivatives catalyzed by tri­fluoro­acetic acid.     

Markov Perfect Equilibrium Existence for a Class of Undiscounted Infinite-Horizon Dynamic Games

We prove the existence of Markov perfect equilibria (MPE) for nonstationary undiscounted infinite-horizon dynamic games with alternating moves. A suitable finite-horizon equilibrium relaxation, the ending state constrained MPE, captures the relevant features of an infinite-horizon MPE for a long enough horizon, under a uniformly bounded reachability assumption.