Simulation model for shapiro time delay and light deflection experiments

The time delay experiment proposed by I.I. Shapiro in 1964 and conducted in the seventies was the most precise experiment of general relativity until that time. Further experimentation has improved the accuracy level of both the time delay and the light deflection experiments. A simulation model is proposed that involves only a simple mass and time transformation factor involving velocity of light. The light deflection and the time delay experiments are numerically simulated using this model that does not use the general relativistic equations. The computed values presented in this paper compare well with recent levels of accuracy of their respective experimental results.     

Analysis of cyathane-type diterpenoids from Cyathus striatus and Hericium erinaceus by high-resolution MALDI MS imaging

Fungal secondary metabolites in both fruiting bodies and pellets from submerged cultures of basidiomycetes were analyzed by atmospheric pressure matrix-assisted laser desorption/ionization-mass spectrometry imaging at a lateral resolution of 15 μm, a mass resolution of 140,000 at m/z 200 and a mass accuracy of better than 2 ppm. The striatals A, B, C, and D, and a number of erinacine type metabolites were detected in the basidiomycetes Cyathus striatus and Hericium erinaceus, respectively. The two fungi were selected as model species, as they are well-known for efficient production of terpenoid secondary metabolites with interesting biological activities, e.g., antibacterial, fungicidal, cytotoxic properties, and stimulating effects on nerve growth factor synthesis. The localization of metabolites revealed a mostly homogeneous distribution of the striatals in the pellets of C. striatus, while a concentration gradient, increasing to the center, was observed in the pellets of H. erinaceus. A mostly homogeneous distribution of metabolites was also found in the fruiting body of H. erinaceus.     

Ba(1-x)K(x)Mn2As2: an antiferromagnetic local-moment metal

The compound BaMn2As2 with the tetragonal ThCr2Si2 structure is a local-moment antiferromagnetic insulator with a Néel temperature T(N)=625 K and a large ordered moment μ=3.9μ(B)/Mn. We demonstrate that this compound can be driven metallic by partial substitution of Ba by K while retaining the same crystal and antiferromagnetic structures together with nearly the same high T(N) and large μ. Ba(1-x)K(x)Mn2As2 is thus the first metallic ThCr2Si2-type MAs-based system containing local 3d transition metal M magnetic moments, with consequences for the ongoing debate about the local-moment versus itinerant pictures of the FeAs-based superconductors and parent compounds. The Ba(1-x)K(x)Mn2As2 class of compounds also forms a bridge between the layered iron pnictides and cuprates and may be useful to test theories of high T(c) superconductivity.     

Schur complement preconditioners for anisotropic problems

We present two new variants of Schur complement domain decompositionpreconditioners suitable for 2D anisotropic problems. Thesevariants are based on adaptations of the probing idea, describedby Chan et al (1992 Fifth Int. Symp. on Domain DecompositionMethods for Partial Differential Equations, Philadelphia: SIAM,pp 236-249), used in conjunction with a coarse grid approximationas introduced by Bramble et al (1986 Math. Comput. 47, 103-134).The new methods are specifically designed for situations wherethe coupling between neighbouring interfaces is stronger thanthe coupling within an interface. Taking into account this strongcoupling, one variant uses a multicolour probing technique toavoid distortion in the probe approximations that appear whenusing the method proposed by Chan et al. The second techniqueuses additional probe matrices to approximate not only the couplingwithin the interfaces but also the coupling between interfacepoints across the subdomains. This latter procedure looks somewhatlike an alternating line relaxation method for anisotropic problems,see Brandt (1977 Math. Comput.. 31, 333-390). To assess therelevance of the new preconditioners, we compare their numericalbehaviour with well known robust preconditioners such as thebalanced Neumann-Neumann method proposed by Mandel (1993 Commun.Numer. Methods Eng.. 9, 233-241).     

评《马氏决策过程》

（《马氏决策过程》,侯振挺、郭先平著,长沙,湖南科技出版社,1997,中文版,386页,定价：28元）马尔可夫决策过程是概率论的运筹学的理论研究和实际应用中极其重要的领域之一．随着中国和国际上对马尔可夫决策过程（MarkovDecisionProcesses,简记为MDP）研究的新进展,许     

Benzothiazole-based chemosensor for CN− and Cu2+: multi-logic operations within a single molecule

2-Hydroxy-1-naphthaldehyde-based benzothiazole chemosensor (1) undergoes absorption and fluorescence changes with addition of CN^?  and Cu²⁺ ions. Addition of CN^?  ions results in the appearance of two new bands at 420 and 440 nm. However, Cu²⁺ addition causes decrease in absorption band at 370 nm up to 12 equiv., while addition of higher equiv. of Cu²⁺(～190 equiv.) results in the appearance of two new bands at 400 and 800 nm. Differential absorption changes observed with addition of Cu²⁺ and CN^?  ions results in the construction of ‘NOR’ and ‘INHIBIT’ logic gates at 370 and 440 nm, respectively.     

Chalcogen Bonding in Co-Crystals: Activation through 1,4-Perfluorophenylene vs. 4,4′-Perfluorobiphenylene Cores

The ability of alkylseleno/alkyltelluroacetylenes such as bis(selenomethylethynyl)-perfluorobenzene (4F-Se) to act as a ditopic chalcogen bond (ChB) donor in co-crystals with ditopic Lewis bases such as 4,4′-bipyridine is extended here to the octafluorobiphenylene analog, 4,4′-bis(selenomethylethynyl)-perfluorobiphenyl (8F-Se), with the more electron-rich 4,4′-bipyridylethane (bpe), showing in the 1:1 (8F-Se)•(bpe) co-crystal a shorter and more linear C−Se•••N ChB interaction than in (4F-Se)•(bpe), with Se•••N distances down to 2.958(2) Å at 150 K, i.e., a reduction ratio of 0.85 vs. the van der Waals contact distance.     

What controls the phase diagram and superconductivity in Ru-substituted BaFe2As2?

We use high resolution angle-resolved photoemission to study the electronic structure of the iron based high-temperature superconductors Ba(Fe(1-x)Ru(x))(2)As(2) as a function of Ru concentration. We find that substitution of Ru for Fe is isoelectronic, i.e., it does not change the value of the chemical potential. More interestingly, there are no measured, significant changes in the shape of the Fermi surface or in the Fermi velocity over a wide range of substitution levels (0相似文献   

Simulation model for anomalous precession of the perihelion of mercury's orbit

The ‘anomalous perihelion precession’ of Mercury, announced by Le Verrier in 1859, was a highly controversial topic for more than half a century and invoked many alternative theories until 1916, when Einstein presented his theory of general relativity as an alternative theory of gravitation and showed perihelion precession to be one of its potential manifestations. As perihelion precession was a directly derived result of the full General Theory and not just the Equivalence Principle, Einstein viewed it as the most critical test of his theory. This paper presents the computed value of the anomalous perihelion precession of Mercury's orbit using a new relativistic simulation model that employs a simple transformation factor for mass and time, proposed in an earlier paper. This computed value compares well with the prediction of general relativity and is, also, in complete agreement with the observed value within its range of uncertainty. No general relativistic equations have been used for computing the results presented in this paper.