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1.
We report on phototriggered Ru-S --> Ru-O and thermal Ru-O --> Ru-S intramolecular linkage isomerizations in cis- and trans-[Ru(bpy)2(dmso)2]2+. The cis complex features only S-bonded sulfoxides (cis-[S,S]), whereas the trans isomer is characterized by S- and O-bonded dmso ligands. Both cis-[S,S] and trans-[S,O] exhibit photochromism at room temperature in dmso solution and ionic liquid (IL). Rates of reaction in IL were monitored by UV-visible spectroscopy and are similar to those reported in dmso solution (k(O-->S) ranges from approximately 10(-3) to 10(-4) s(-1)). Cyclic voltammetric measurements of cis-[S,S] and trans-[S,O] are consistent with an electrochemically triggered linkage isomerism mechanism. While both cis-[S,S] and trans-[S,O] are photochromic at room temperature, neither complex is emissive. However, upon cooling to 77 K, cis-[S,S] exhibits LMCT (ligand-to-metal charge transfer) emission typical of many ruthenium polypyridine complexes. In contrast to cis-[S,S], trans-[S,O] does not show any detectable emission even at 77 K. 相似文献
2.
Survila A. Mockus Z. Kanapeckaitė S. Jasulaitienė V. 《Russian Journal of Electrochemistry》2004,40(8):855-859
Voltammetry and x-ray photoelectron spectroscopy data show micromolar amounts of halides to noticeably affect co-deposition of copper and tin from acidic sulfate solutions containing polyether Laprol 2402C as the surface-active substance. The reduction of Cu(II) slows down and that of Sn(II) accelerates in the series Cl– < Br– < I–. Compounds on the surface of bronze coatings are oxides of Cu(I) and Sn(II) and halides of Cu(I). 相似文献
3.
William F. Eddy Mark Fitzgerald Christopher Genovese Nicole Lazar Audris Mockus Joel Welling 《Journal of computational and graphical statistics》2013,22(3):545-558
Abstract Functional magnetic resonance imaging of the human brain in action presents large statistical and computational challenges. Here we describe those challenges and provide references to a number of other papers where detailed methods developed to meet them are reported. The first seven sections of this paper were written in 1995 when our work was in its infancy. The last four sections were written more recently, to update the earlier sections and to show the directions we have gone and the directions we intend to go. 相似文献
4.
We report the structure, spectroscopy, and electrochemistry of cis-[Os(bpy)(2)(DMSO)(2)](OTf)(2), where bpy is 2,2'-bipyridine, DMSO is dimethyl sulfoxide, and OTf is trifluoromethanesulfonate. Electrochemical measurements are consistent with S-to-O isomerization following the oxidation of Os(2+) (1.8 V vs Ag/AgCl). Visible irradiation of the metal-to-ligand charge-transfer transition (355 nm) of [Os(bpy)(2)(DMSO)(2)](2+) in the solid state and solution yields an emissive S-bonded excited state and S-to-O excited-state isomerization on a subnanosecond time scale. These results and a comparison to the nonphotoactive [Os(bpy)(2)Cl(DMSO)](+) are discussed. 相似文献
5.
Audris Mockus 《Journal of computational and graphical statistics》2013,22(4):501-513
Abstract Modeling of space-time functions can be done using observations in the form of averages of the function over a set of irregularly shaped regions in space-time. Such observations are most common in applications where the data are gathered for administrative, political, geographic, or agricultural regions. The value of such functions can be predicted by first estimating the dependence structure of the underlying stochastic process. Our proposed method for estimating the covariance function from the integrals of a stationary isotropic stochastic process poses the problem as a set of integral equations. To test this proposal we applied it to epidemiological data on the incidence rates of three diseases in the United States between 1980 and 1994. Spatial correlations obtained in this way reasonably described the mechanism by which those diseases spread. We therefore conclude that it is possible to reliably estimate covariance functions from aggregate observations. The estimate of the covariance functions provides valuable insights into the nature of the space-time process—in the epidemiological data it described a possible mechanism by which the diseases spread. 相似文献
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A. Survila Z. Mockus S. Kanapeckaite J. Pileckiene G. Stalnionis 《Russian Journal of Electrochemistry》2011,47(2):129-135
The kinetics of cathodic processes proceeding in the acidic 0.01 M Cu(II) solutions containing gluconic acid and 0.5 M Na2SO4 as the supporting electrolyte is studied. According to the spectrophotometric data, in the moderately acidic solutions, a
monoligand complex of CuL+ predominantly forms. Its concentration stability constant is 102.2 M−1. In the cathodic voltammograms, a well-defined plateau of the limiting current is observed. The height of the plateau obeys
the Levich equation. The effective diffusion coefficient decreases from 4.2 × 10−6 to 2.5 × 10−6 cm2/s with increasing complexation degree of the system. An analysis of normalized Tafel plots showed that the exchange current
density of Cu2+ + e → Cu+ process decreases with increasing concentration of ligand or with increasing pH value. Thereby, the cathodic chargetransfer
coefficient remains constant (0.33 ± 0.02). A comparison of the kinetic data with the results of deposit surface examination
points to significant surface activity of the ligand. The gluconate chemisorption can be accompanied by the incorporation
of the fragments, which were formed as a result of its destruction, into the electrodeposits. 相似文献
8.
Jonas Mockus 《Journal of Global Optimization》2010,48(1):129-143
Unlike physical time series, stock market prices may be affected by the predictions made by market participants with conflicting
interests. This is the domain of game theory. Therefore, we propose a Stock Exchange Game Model (SEGM) to model this phenomenon.
In SEGM, player strategies are to set their buying and selling levels for the next iteration via the autoregressive model
AR(p) of order p selected by minimizing deviations from Nash Equilibrium (NE). NE represents the assumption of optimal behavior
by market participants. The objective of SEGM is to simulate financial and other time series that are affected by predictions
of the participants and to test the assumption of optimal player behavior, using a ‘virtual’ stock exchange. The simulation
of SEGM suggests that NE is close to the Wiener model. This is a new explanation of the Random Walk (RW) model of the efficient
market theory. To compare the simulation results with real data, the efficient market hypothesis was also tested, using financial
time series of eight assets. The SEGM software is implemented in Java applets and can be run using a browser with Java support.
The main web site is in . 相似文献
9.
Arvydas Survila Dalia Bražinskienė Stasė Kanapeckaitė Zenius Mockus Vitalija Jasulaitienė 《Journal of Solid State Electrochemistry》2010,14(4):507-514
Voltammetry and electrochemical impedance spectroscopy technique were applied to study the effect of polyethylene glycols
(PEG) with different molecular mass on Cu(II) and Sn(II) reduction kinetics in acidic sulfate solutions. Tetraethylene glycol
was found to be the surface-active oligomer on both Cu and Sn substrates that holds the shortest (–CH2–CH2–O–)m chain. The exchange current density of the rate-limiting step Cu2+ + e → Cu+ falls drastically with an increase in the molecular mass of PEG. An addition of PEG into halide-free Sn(II) solutions results
in the significant inhibition of Sn(II) reduction in the entire range of cathodic polarizations including the region of limiting
current. Inhibition degree also increases with PEG molecular mass. In contrast with Cu|Cu(II) system, formation of adsorption
layers on Sn electrodes proceeds significantly slower. Underpotential deposition of Sn(II) is observed in the region of Cu(II)-limiting
current. The characteristic current minimum arises in the region where free Sn phase is thermodynamically stable. It deepens
with the length of the hydrocarbon chain of PEG. The fall of current density seems to arise from the inhibitive PEG adsorption
on tin atoms that are still not incorporated into general Cu–Sn lattice. 相似文献
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