High accuracy results for the energy levels of the molecular ions H2+, D2+ and HD+, up to J=2

We present a nonrelativistic calculation of the rotation-vibration levels of the molecular ions H2+, D2+ and HD+, relying on the diagonalization of the exact three-body Hamiltonian. The J=2 levels are obtained with a very high accuracy of 10^{-14} a.u. (for most levels) representing an improvement by five orders of magnitude over previous calculations. The accuracy is also improved for the J=1 levels of H2+ and D2+ with respect to earlier works. Moreover, we have computed the sensitivities of the energy levels with respect to the mass ratios, allowing these levels to be used for metrological purposes.Comment: 11 page

The thermal analysis of cutting/grinding processes by meshless finite block method

© 2018 Elsevier Ltd Development of the Finite Block Method (FBM) is presented, with the introduction of infinite elements for the first time, for predicting stationary and transient heat conduction in cutting/grinding processes. Utilizing the Lagrange series the first order partial differential matrix is derived, adopting a mapping technique, followed by the construction of the higher order derivative matrix. For linear stationary heat conductivity three free parameters including the velocity of the workpiece, the cooling coefficient and the inclined angle of the contact zone, together with their effects on temperature, are observed. For the transient heat conduction study, the Laplace transformation method and Durbin's inverse technique are employed. Numerical solutions are discussed and comparisons made with the finite element method and analytical solutions, demonstrating the accuracy and convergence of the finite block method

Hunting for planets in the HL Tau disk

Recent ALMA images of HL Tau show gaps in the dusty disk that may be caused by planetary bodies. Given the young age of this system, if confirmed, this finding would imply very short timescales for planet formation, probably in a gravitationally unstable disk. To test this scenario, we searched for young planets by means of direct imaging in the L'-band using the Large Binocular Telescope Interferometer mid-infrared camera. At the location of two prominent dips in the dust distribution at ~70AU (~0.5") from the central star we reach a contrast level of ~7.5mag. We did not detect any point source at the location of the rings. Using evolutionary models we derive upper limits of ~10-15MJup at <=0.5-1Ma for the possible planets. With these sensitivity limits we should have been able to detect companions sufficiently massive to open full gaps in the disk. The structures detected at mm-wavelengths could be gaps in the distributions of large grains on the disk midplane, caused by planets not massive enough to fully open gaps. Future ALMA observations of the molecular gas density profile and kinematics as well as higher contrast infrared observations may be able to provide a definitive answer.Comment: Accepted for publication on ApJ Letter

A RISC-V Vector Processor With Simultaneous-Switching Switched-Capacitor DC-DC Converters in 28 nm FDSOI

This work demonstrates a RISC-V vector microprocessor implemented in 28 nm FDSOI with fully integrated simultaneous-switching switched-capacitor DC-DC (SC DC-DC) converters and adaptive clocking that generates four on-chip voltages between 0.45 and 1 V using only 1.0 V core and 1.8 V IO voltage inputs. The converters achieve high efficiency at the system level by switching simultaneously to avoid charge-sharing losses and by using an adaptive clock to maximize performance for the resulting voltage ripple. Details about the implementation of the DC-DC switches, DC-DC controller, and adaptive clock are provided, and the sources of conversion loss are analyzed based on measured results. This system pushes the capabilities of dynamic voltage scaling by enabling fast transitions (20 ns), simple packaging (no off-chip passives), low area overhead (16%), high conversion efficiency (80%-86%), and high energy efficiency (26.2 DP GFLOPS/W) for mobile devices

Estimations of changes of the Sun's mass and the gravitation constant from the modern observations of planets and spacecraft

More than 635 000 positional observations (mostly radiotechnical) of planets and spacecraft (1961-2010), have been used for estimating possible changes of the gravitation constant, the solar mass, and semi-major axes of planets, as well as the value of the astronomical unit, related to them. The analysis of the observations has been performed on the basis of the EPM2010 ephemerides of IAA RAS in post-newtonian approximation. The obtained results indicate on decrease in the heliocentric gravitation constant per year at the level $\dot {GM_{Sun}}/GM_{Sun} = (-5.0 \pm 4.1) 10^{-14} (3\sigma).$ The positive secular changes of semi-major axes $\dot a_i/a_i$ have been obtained simultaneously for the planets Mercury, Venus, Mars, Jupiter, Saturn, as expected if the geliocentric gravitation constant is decreasing in century wise. The change of the mass of the Sun $M_{Sun}$ due to the solar radiation and the solar wind and the matter dropping on the Sun (comets, meteors, asteroids and dust) was estimated. Taking into account the maximal limits of the possible $M_{Sun}$ change, the value $\dot G/G$ falls within the interval $-4.2\cdot10^{-14} < \dot G/G < +7.5\cdot10^{-14}$ in year with the 95% probability. The astronomical unit (au) is only connected with the geliocentric gravitation constant by its definition. In the future, the connection between $GM_{Sun}$ and au should be fixed at the certain time moment, as it is inconvenient highly to have the changing value of the astronomical unit.Comment: 20 pages, 4 tables, accepted for publication in Solar System Research, 2011 (Astronomicheskii vestnik

New mobilities across the lifecourse: A framework for analysing demographically-linked drivers of migration

Date of acceptance: 17/02/2015Taking the life course as the central concern, the authors set out a conceptual framework and define some key research questions for a programme of research that explores how the linked lives of mobile people are situated in time–space within the economic, social, and cultural structures of contemporary society. Drawing on methodologically innovative techniques, these perspectives can offer new insights into the changing nature and meanings of migration across the life course.Publisher PDFPeer reviewe

Negative Thermal Expansion Coefficient of Graphene Measured by Raman Spectroscopy

The thermal expansion coefficient (TEC) of single-layer graphene is estimated with temperature-dependent Raman spectroscopy in the temperature range between 200 and 400 K. It is found to be strongly dependent on temperature but remains negative in the whole temperature range, with a room temperature value of -8.0x10^{-6} K^{-1}. The strain caused by the TEC mismatch between graphene and the substrate plays a crucial role in determining the physical properties of graphene, and hence its effect must be accounted for in the interpretation of experimental data taken at cryogenic or elevated temperatures.Comment: 17 pagese, 3 figures, and supporting information (4 pages, 3 figures); Nano Letters, 201

Sexual Arousal Patterns of Identical Twins with Discordant Sexual Orientations

Genetically identical twins can differ in their self-reported sexual orientations. However, whether the twins’ subjective reports reflect valid differences in their sexual orientations is unknown. Measures of sexual orientation, which are free of the limitations of self-report, include genital arousal and pupil dilation while viewing sexual stimuli depicting men or women. We examined these responses in 6 male twin pairs and 9 female twin pairs who reported discordant sexual orientations. Across measures, heterosexual male twins responded more strongly to women than to men. Their homosexual co-twins showed an opposite pattern. Heterosexual female twins responded equally to both sexes, whereas their homosexual co-twins responded somewhat more to women than men. These differences within pairs were similar to differences between unrelated heterosexual and homosexual males and females. Our study provides physiological evidence confirming twins’ discordant sexual orientations, thereby supporting the importance of the non-shared environment for the development of sexual orientation and sexual arousal