Observation of electron transfer mediated decay in aqueous solution

Photoionization is at the heart of X ray photoelectron spectroscopy XPS , which gives access to important information on a sample s local chemical environment. Local and non local electronic decay after photoionization in which the refilling of core holes results in electron emission from either the initially ionized species or a neighbour, respectively have been well studied. However, electron transfer mediated decay ETMD , which involves the refilling of a core hole by an electron from a neighbouring species, has not yet been observed in condensed phase. Here we report the experimental observation of ETMD in an aqueous LiCl solution by detecting characteristic secondary low energy electrons using liquid microjet soft XPS. Experimental results are interpreted using molecular dynamics and high level ab initio calculations. We show that both solvent molecules and counterions participate in the ETMD processes, and different ion associations have distinctive spectral fingerprints. Furthermore, ETMD spectra are sensitive to coordination numbers, ion solvent distances and solvent arrangemen

Eine Abschätzung des Risikos der Inkorporation von Schwerwasser (D2_{2}O) in den menschlichen Organismus

Data from literature are reported, whieh show the effeet of the isotope deuterium, instead of hydrogen, on various organisms. Deuterium is introdueed normally as heavy water (D$_{2}$O). The application of deuterium instead of hydrogen mainly ehanges the enzymatic reactions. Therefore, while the relative deuterium contentincreases, the function of the organisms is disturbed. Comparing with mammals the man should tolerate a concentration of 10 % D$_{2}$O (body water). This level can only be reached by a rapid drinking of about 5 liter D$_{2}$O, or by drinking 020 instead of water during 4 days at a normal rate. These situations normally should not occur. Therefore, heavy water should not generally be considered as a toxic substance

Das 18^{18}O/16^{16}O Verhältnis im Jülicher Niederschlag 1974 - 1982 und seine Korrelation mit meteorologischen und chemischen Daten

From 1974 to 1982 precipitation in Jülich were collected during each month. The $^{18}$O/$^{16}$O-ratio, the pH and the concentration of calcium, chloride and sulfate were determined. The sampling unit did not collect the precipitation alone, but also the drydeposition, too. Correlation studies between all results demonstrate, that the 180/ 160-ratio of precipitation can be an indicator of air temperature. Wind directions, measured near the ground, cannot be used as a tracer for the movement and dynamic of precipitation. The air temperature, possibly as a stimulator of the heating, is correlated with an increased concentration of calcium and sulfat, and a decrease of the pH. A rise of the sum of precipitation only dilutes the amount of ions deposited. As a general result, important for other applications, the constancy of the $^{18}$O/$^{16}$O-ratio of precipitation in Jülich has been confirmed for a observation period of eight years

Das O-018/O-016 Verhältnis des Niederschlages in der KFA Jülich 1974 bis Mitte 1978

Since 1974 until June 1978 we collected samples of precipitation at the site of the Nuclear Research Center Jülich. Single precipitations, which we took during 1974, show a large variation of the $^{18}$O/$^{16}$O ratio even within one day. The variation diminishes, if one compares the $^{18}$O/$^{16}$O ratios of precipitation which was collected and pooled during each month. At our location we can see a minimum of the oxygen isotope ratio at March. The average of the $^{18}$O/$^{16}$O ratio in the precipitation weighted by the amount of precipitation since 1974 until 1977 is -7.42 $^\circ$/$_\circ$$_\circ$ (related to Vienna-SMOW). The large seattering of the oxygen isotope ratio between single precipitations must be taken into account, if one works under field conditions. The results are the basic data, which help to describe the water turnover of our local ecosystem and the isotope fractionation of the biogeochernical oxygen cycle

Stochastic reliable control of a class of uncertain time-delay systems with unknown nonlinearities

Copyright [2001] IEEE. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.This paper investigates the robust reliable control problem for a class of nonlinear time-delay stochastic systems. The system under study involves stochastics, state time-delay, parameter uncertainties, possible actuator failures and unknown nonlinear disturbances, which are often encountered in practice and the sources of instability. Our attention is focused on the design of linear state feedback memoryless controllers such that, for all admissible uncertainties as well as actuator failures occurring among a prespecified subset of actuators, the plant remains stochastically exponentially stable in mean square, independent of the time delay. Sufficient conditions are proposed to guarantee the desired robust reliable exponential stability despite possible actuator failures, which are in terms of the solutions to algebraic Riccati inequalities. An illustrative example is exploited to demonstrate the applicability of the proposed design approac