Search results for "interaction [electron p]"
showing 10 items of 282 documents
New Insights and Recent Developments in Micellar Liquid Chromatography
2009
Abstract: Micellar liquid chromatography (MLC) is an efficient alternative to conventional reversed–phase liquid chromatography with hydro‐organic mobile phases. Almost three decades of experience have resulted in an increasing production of analytical applications. Current concern about the environment also reveals MLC as an interesting technique for “green” chemistry because it uses mobile phases containing 90% or more water. These micellar mobile phases have a low toxicity and are not producing hazardous wastes. After a rapid overview of the two first decades of the technique, this review focuses on the recent advances on fundamental aspects and analytical applications. Traditional and n…
Interaction Control of Robotic Manipulators Without Force Measurement
2010
This paper deals with a new adaptive force-position control of a robotic manipulator based on force estimation. Based on Lyapunov techniques will be proved that the control law guaranties tracking of the desired Cartesian trajectory along the contact plane and of a constant desired force along reciprocal direction, without force measuring. Extensive simulations with 2-DOF manipulator illustrates the followed approach.
Molecular Motions within Self-Assembled Dimeric Capsules with Tetraethylammonium Cations as Guest
2001
Hydrogen-bonded, dimeric capsules of calix[4]arenes substituted at the wide rim by four urea functions show unprecedented dynamic features when a tetraethylammonium cation is included as a guest. The seam of hydrogen bonds C=O...(HN)2C=O in the equatorial region which holds the two calixarene counterparts together changes its directionality fast (at 25 degrees C), while the dimer itself is kinetically stable on the NMR time scale. An energy barrier of deltaG++ = 49.9 kJmol(-1) (Tc 276 K) was estimated for this reorientation from variable-temperature (VT) NMR measurements. Lowering the temperature to about -50 degrees C restricts also the rotation of the encapsulated tetraethylammonium catio…
Maximin Model Robust Discrete Choice Experiments
2013
Discrete choice experiments have their genesis in conjoint analysis, which was based on first-order models. For this and other reasons, discrete choice experiments in practice are usually designed for estimation of main effects. In this paper, we explore the construction of maximin model robust designs when the experimenter is concerned about the presence of interactions. We consider three classes of models—main effects models, main effects models plus first-order interactions, and secondorder models, and we construct designs that maximize the minimum efficiency of the design for the three competing models. We do so first with standard linear models and then extend our analysis to nonlinear…
The use of high-pressure liquid cation-exchange chromatography for determination of the 5-methylcytosine content of DNA.
1976
Emotional labour and work engagement among nurses: examining perceived compassion, leadership and work ethic as stress buffers
2015
Aim The study examined whether three resources, that is, compassion, transformational leadership and work ethic feasibility, buffer against the negative effects of emotional labour on work engagement. Background Emotional labour is a common job stressor among nurses, but little is known about whether certain personal and work resources buffer against it in relation to work engagement. Revealing buffers of emotional labour would help organizations to design tailored interventions. Design Cross-sectional online survey conducted in 2014. Methods Participants were 3466 Finnish nurses. Hypotheses were tested via hierarchical moderated regression analyses. Results Higher emotional labour related …
Changes in beverage consumption in Norwegian children from 2001 to 2008
2011
AbstractObjectiveTo analyse (i) differences in beverage pattern among Norwegian children in 2001 and 2008; (ii) beverage intake related to gender, parental education and family composition; and (iii) potential disparities in time trends among the different groups.DesignWithin the Fruits and Vegetables Make the Marks (FVMM) project, 6th and 7th grade pupils filled in a questionnaire about frequency of beverage intake (times/week) in 2001 and 2008.SettingTwenty-seven elementary schools in two Norwegian counties.SubjectsIn 2001 a total of 1488 and in 2008 1339 pupils participated.ResultsBetween 2001 and 2008, a decreased consumption frequency of juice (from 3·6 to 3·4 times/week, P = 0·012), l…
Modeling the Interaction of Carbon Monoxide with Flexible Graphene: From Coupled Cluster Calculations to Molecular-Dynamics Simulations
2018
The interaction of CO with graphene was studied at different theoretical levels. Quantum-mechanical calculations on finite graphene models with the use of coronene for coupled cluster calculations and circumcoronene for B97D calculations showed that there was no preferential site for adsorption and that the most important factor was the orientation of CO relative to graphene. The parallel orientation was preferred, with binding energies around 9 kJ mol-1 at the CCSD(T) and B97D levels, which was in good agreement with experimental findings. From a large number of CO-circumcoronene and CO-CO interactions, computed at different distances and randomly generated orientations, parameters were fi…
Nitrogen Gas on Graphene: Pairwise Interaction Potentials
2018
We investigate different types of potential parameters for the graphene-nitrogen interaction. Interaction energies calculated at DFT level are fitted with the semi-emperical Improved Lennard-Jones potential. Both a pseudo-atom potential and a full atomistic potential are considered. Furthermore, we consider the influence of the electrostatic part on the parameters using different charge schemes found in the literature as well as optimizing the charges ourselves. We have obtained parameters for both the nitrogen dimer and the graphene-nitrogen system. For the former, the four-charges Cracknell scheme reproduces with high precision the CCSD(T) interaction energy as well as the experimental di…
Structure and dynamics of B2O3 melts and glasses: From ab initio to classical molecular dynamics simulations
2019
Abstract Boron oxide (B2O3) is investigated by a combination of ab initio (DFT-based) molecular dynamics (MD) simulations and classical MD simulations. From the trajectories of the ab initio MD simulation, we derive a three-body interaction potential which is used in classical MD simulations to study various structural and dynamic properties on larger time and length scales than possible in the ab initio simulations. Differences and similarities to the structure and dynamics of other network glass formers such as SiO2 and GeO2 are discussed. Moreover, various properties as obtained from the simulations are compared to those from experiments of B2O3.