Silver-catalyzed carboxylation Sekine, K; Yamada, T
Chemical Society reviews,
08/2016, Letnik:
45, Številka:
16
Journal Article
Recenzirano
Odprti dostop
Silver-catalyzed reactions are some of the important methodologies in organic chemistry. Since 2007, a new application of silver catalysts has been emerging. For the sequential carboxylation and ...cyclization of alkyne derivatives, such as propargyl alcohols and amines, using carbon dioxide, silver catalysts show significant reactivity under mild conditions unlike other transition metals. These developments have received much attention for the effective utilization of carbon dioxide in organic chemistry to synthesize heterocyclic compounds. Related silver-catalyzed C-C bond forming reactions with carbon dioxide have also provided the synthetic methods of the corresponding carboxylic acid derivatives. In this review, the recent studies of the silver-catalyzed carboxylation reactions using carbon dioxide are described.
The recent studies of the silver-catalyzed carboxylation reactions using carbon dioxide are described.
In the context of climate change, salinity intrusion into rivers has been, and will be, one of the most important issues for coastal water resources management. A combination of changes, including ...increased temperature, change in regional rainfall, especially sea level rise (SLR) related to climate change, will have significant impacts on this phenomenon. This paper presents the outcomes of a study conducted in the Mekong Delta of Vietnam (MKD) for evaluating the effect of sea water intrusion under a new SLR scenario. Salinity intrusion was simulated by one-dimensional (1D) modeling. The relative sea level projection was constructed corresponding to the RCP 6.0 emission scenario for MKD based on the statistical downscaling method. The sea level in 2050 is projected to increase from 25 cm to 30 cm compared to the baseline period (in 2000). Furthermore, the simulated results suggested that salinity greater than 4 g/l, which affects rice yield, will intrude up to 50-60 km into the river. Approximately 30,000 ha of agricultural area will be affected if the sea level rise is 30 cm.
Cosmological simulations predict that the Universe contains a network of intergalactic gas filaments, within which galaxies form and evolve. However, the faintness of any emission from these ...filaments has limited tests of this prediction. We report the detection of rest-frame ultraviolet Lyman-α radiation from multiple filaments extending more than one megaparsec between galaxies within the SSA22 protocluster at a redshift of 3.1. Intense star formation and supermassive black-hole activity is occurring within the galaxies embedded in these structures, which are the likely sources of the elevated ionizing radiation powering the observed Lyman-α emission. Our observations map the gas in filamentary structures of the type thought to fuel the growth of galaxies and black holes in massive protoclusters.
MIL-101(Fe) was investigated as a cathode material of lithium ion batteries. A battery test reveals that MIL-101(Fe) shows a charge and discharge capacitance of 110 mA h g
. It also showed reversible ...charge and discharge cycles and uptake of 0.62 Li/Fe after 100 cycles, which is the highest loading amount ever reported for the carboxylic MOFs. It also operates in the temperature range up to 350 °C and showed a good high thermal stability.
Chiral spin textures of a ferromagnetic layer in contact to a heavy non-magnetic metal, such as Néel-type domain walls and skyrmions, have been studied intensively because of their potential for ...future nanomagnetic devices. The Dyzaloshinskii-Moriya interaction (DMI) is an essential phenomenon for the formation of such chiral spin textures. In spite of recent theoretical progress aiming at understanding the microscopic origin of the DMI, an experimental investigation unravelling the physics at stake is still required. Here we experimentally demonstrate the close correlation of the DMI with the anisotropy of the orbital magnetic moment and with the magnetic dipole moment of the ferromagnetic metal in addition to Heisenberg exchange. The density functional theory and the tight-binding model calculations reveal that inversion symmetry breaking with spin-orbit coupling gives rise to the orbital-related correlation. Our study provides the experimental connection between the orbital physics and the spin-orbit-related phenomena, such as DMI.
Experimental ground-state combination differences of CH5 Asvany, Oskar; Yamada, Koichi M. T.; Brünken, Sandra ...
Science (American Association for the Advancement of Science),
03/2015, Letnik:
347, Številka:
6228
Journal Article
Recenzirano
Protonation of methane (CH4), a rather rigid molecule well described by quantum mechanics, produces CH5+, a prototypical floppy molecule that has eluded definitive spectroscopic description. ...Experimental measurement of high-resolution spectra of pure CH5+ samples poses a formidable challenge. By applying two types of action spectroscopy predicated on photoinduced reaction with CO2 and photoinhibition of helium cluster growth, we obtained low-temperature, high-resolution spectra of mass-selected CH5+. On the basis of the very high accuracy of the line positions, we determined a spectrum of combination differences. Analysis of this spectrum enabled derivation of equally accurate ground state–level schemes of the corresponding nuclear spin isomers of CH5+, as well as tentative quantum number assignment of this enfant terrible of molecular spectroscopy.
In this study, we propose a new topology optimization problem for creep deformation minimization. It is a phenomenon in which deformation progresses even when the load is constant, and is a cause of ...damage to mechanical parts. Therefore, the results of this paper will be one of the solutions to the problem of creep deformation. We deal with a viscoelastic model assuming the generalized Maxwell model to account for creep deformation. In addition, we devise a new objective function that directly evaluate the creep deformation. Since sensitivity analysis of the objective function is necessary for topology optimization, we formulate the sensitivity of the viscoelastic model to accurately consider the time dependence. The relationship between the creep characteristics and the objective function is explained through a numerical example using a one-dimensional model. By examining a two-dimensional model, it is shown that the formulated sensitivity is validated and the proposed method derives the optimized configuration under which creep deformation is minimized.
•We propose a topology optimization for minimizing creep deformation.•We apply the generalized Maxwell model to simulate creep deformation.•A new optimization problem that enables creep deformation minimization is introduced.•We present a sensitivity analysis that considers the history dependency of deformation.
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