Search results for "Potential difference"
showing 8 items of 8 documents
Determination of Contact Potential Difference by the Kelvin Probe (Part II) 2. Measurement System by Involving the Composite Bucking Voltage
2016
Abstract The present research is devoted to creation of a new low-cost miniaturised measurement system for determination of potential difference in real time and with high measurement resolution. Furthermore, using the electrode of the reference probe, Kelvin method leads to both an indirect measurement of electronic work function or contact potential of the sample and measurement of a surface potential for insulator type samples. The bucking voltage in this system is composite and comprises a periodically variable component. The necessary steps for development of signal processing and tracking are described in detail.
Determination of Contact Potential Difference by the Kelvin Probe (Part I) I. Basic Principles of Measurements
2016
Abstract Determination of electric potential difference using the Kelvin probe, i.e. vibrating capacitor technique, is one of the most sensitive measuring procedures in surface physics. Periodic modulation of distance between electrodes leads to changes in capacitance, thereby causing current to flow through the external circuit. The procedure of contactless, non-destructive determination of contact potential difference between an electrically conductive vibrating reference electrode and an electrically conductive sample is based on precise control measurement of Kelvin current flowing through a capacitor. The present research is devoted to creation of a new low-cost miniaturised measuremen…
Changes in transition times in ‘Ironman Hawaii’ between 1998 and 2013
2014
International audience; BackgroundRecent findings showed that elite Ironman triathletes competing in ‘Ironman Hawaii’ improved both split and overall race times. The present study investigated whether elite athletes also improved in transition time (i.e. time needed between disciplines for changing clothes and equipment).MethodsChanges in split times, overall race times and transition times (i.e. expressed in absolute and relative terms) in the annual fastest competing in ‘Ironman Hawaii’ were investigated using linear, non-linear and multi-level regression analyses. To detect a potential difference in transition times between different race distances, we compared transition times in ‘Ironm…
Esophageal transmural potential difference in patients with symptomatic gastroesophageal reflux.
1980
Esophageal electrical potential difference (PD) was studied in 9 patients with symptomatic gastroesophageal reflux and in 9 healthy control subjects. None of the patients revealed gross mucosal damage by radiography or endoscopy, but all of them showed positive acid perfusion studies. In the stomach and across the lower esophageal sphincter PD profiles were remarkably similar in patients and controls. Throughout the lower esophagus however, PD values were slightly higher in patients with symptomatic reflux than in healthy volunteers. These data are in contrast to a previous investigation, in which patients with reflux-induced gross mucosal damage revealed a decreased PD in the lower esophag…
Effect of Bacillus thuringiensis toxins on the midgut of the nun moth Lymantria monacha.
2000
Three steps of the proposed mode of action of Bacillus thuringiensis toxins have been studied in Lymantria monacha. We demonstrated that only the toxins that caused typical pathological changes in midgut epithelial cells and bound to the midgut brush border membrane were able to drastically reduce the midgut transepithelial voltage of the nun moth.
The Influence of All-Night Exposure to Pulsed Radiofrequency Electromagnetic Fields on Human Sleep. Der Einfluss kontinuierlicher nachtlicher Exposit…
2005
Question of the study The widespread use of mobile telephones has led to public discussion about the putative health hazards as well as scientific interest in the interactions of pulsed, high-frequency electromagnetic fields with physiological systems. This article presents a survey of three consecutive studies carried out by a research group at the University of Mainz.
Simulation of first- and second-order transitions in asymmetric polymer mixtures
1993
The critical properties of dense asymmetric binary polymer mixtures are studied by grand canonical simulations within the framework of the 3-dimensional bond fluctuation lattice model. The monomers interact with each other via a potential ranging over the entire first peak of the pair distribution. An asymmetry is realized by giving the ratio of interactions λ = ∈AA/∈BB between monomers of the A-species and of the B-species a value different from 1. Using multiple histogram extrapolation techniques for the data analysis, the two phase region, which is a line of first-order transitions driven by the chemical potential difference, and the critical point are determined for a mixture of chains …
Rhein stimulates active chloride secretion in the short-circuited rat colonic mucosa.
1988
In a short-circuited mucosa-submucosa preparation of the rat descending colon with preserved Meissner's plexus mounted as an everted sac rhein transiently increased the potential difference and short-circuit current (Isc) when administered serosally and mucosally, but serosal application was more effective. Maximal effects were obtained at rhein concentrations of 1.6 X 10(-4) and 3 X 10(-4) mol/l. Net chloride absorption was decreased. Indomethacin (5 X 10(-6) mol/l) did not inhibit the increase of Isc, but omission of calcium from the serosal side as well as tetrodoxin (2 X 10(-7) mol/l) decreased it by 50 and 60%. Mechanical removal of Meissner's plexus partly blocked the effect of rhein,…