Search results for "RADIATION"
showing 10 items of 5298 documents
Fabry–Pérot lineshape analysis in an optically thick expanding plasma
2007
In this work the authors present Fabry–Perot measurements of Ar atom spectral line profiles originating from the expansion of an Ar–N2 thermal plasma into a low pressure environment. The plasma is characterized by strong density, temperature and velocity gradients and it offers a high degree of light absorption for some gas mixtures. First, it is demonstrated that the Abel inversion method cannot be applied under such conditions even if absorption is absent. Second, two approaches are examined to obtain plasma parameters in the case of an optically thick expanding plasma. It is shown that velocity and temperature development along the jet radius can be inferred from experimental lineshapes …
Measurement of rotational relaxation in the ground state of methane perturbed by argon at low temperature
1999
International audience; Relaxation processes at low temperature in methane perturbed by argon have been investigated on the basis of new measurements. Diode laser absorption spectra of methane in the region of the dyad nu2/nu4 in supersonic expansions have been recorded. The time of relaxation of the ground state mean rotational energy was derived from the observed dependences of the rotational temperature on the concentration in the jet. A semi-classical model was used to calculate the state-to-state relaxation rate constants at room temperature. The evaluation of the time of relaxation of the mean rotational energy using semi-empirical temperature dependence laws is presented and discusse…
Time Evolution of two distant SQUID rings irradiated with entangled electromagnetic field
2006
Two distant mesoscopic SQUID rings are irradiated with two mode microwaves produced by the same source. The time evolution of the system is studied. The two microwave modes are correlated. It is shown that the currents tunnelling through the Josephson junctions in the distant rings, are also correlated.
Very large thermophase in ferromagnetic josephson junctions
2014
Under the terms of the Creative Commons Attribution License 3.0 (CC-BY).
Reversible switching of the Au(111) work function by near infrared irradiation with a bistable SAM based on a radical donor–acceptor dyad
2019
We describe the modification of the work function (WF) of Au(111) upon deposition of self-assembled monolayers (SAMs) with two donor–acceptor (D–A) systems, one based on a ferrocene-polychlorotriphenylmethyl radical (Fc–PTM) dyad and another on its non-radical dyad analogue. Kelvin Probe Force Microscopy (KPFM) has been used to measure the changes in the Contact Potential Difference (CPD) between the tip and the SAM under application of a cycling sweep of direct current (DC) voltage bias. These measurements showed that both SAMs exhibit a hysteretic behaviour in their WF changes. Interestingly, the hysteresis loop of the radical SAM is notably reduced when irradiated with NIR light, which w…
Entwicklung der Hornhautdicke während der UV-Vernetzungstherapie unter Anwendung verschiedener Kompositionen von Riboflavin-Augentropfen
2011
Background During the UVA-cross-linking treatment in keratoconus patients, the UVA rays are partially absorbed in the stroma of the riboflavin-loaded cornea. This effect protects the corneal endothelium from UVA irradiation damage. The intensity of UVA light reaching the endothelium is inversely correlated with corneal thickness. The common composition of riboflavin eye drops may lead to a marked reduction in corneal thickness increasing the risk of endothelial damage. Patients and methods In a retrospective analysis of 23 UVA-cross-linking procedures on 23 patients we collected data about the pre-, intra- and postoperative corneal thickness (measured with ultrasound). Among these patients …
Study of Structure–Third-Order Susceptibility Relation of Indandione Derivatives
2016
By using the Z-scan method we studied the third-order nonlinear optical parameters of several aminobenziliden-1,3-indandione (ABI) derivatives that have previously been shown to own second-order nonlinear optical properties. Measurements were carried out using two 1064 nm Nd:YAG lasers with picosecond (ps) and nanosecond (ns) pulse widths, respectively. When ns laser was employed in the Z-scan setup, a strong thermal lensing took place resulting in severe overestimation of optical Kerr coefficients. Due to this reason the ps laser was employed to evaluate correct magnitude of Kerr effect. For investigated organic molecules, experimental results show that two-photon absorption at 1064 nm is …
A Combined Experimental and Theoretical Approach to the Photogeneration of 5,6-Dihydropyrimidin-5-yl Radicals in Nonaqueous Media
2016
The chemical fate of radical intermediates is relevant to understand the biological effects of radiation and to explain formation of DNA lesions. A direct approach to selectively generate the putative reactive intermediates is based on the irradiation of photolabile precursors. But, to date, radical formation and reactivity have only been studied in aqueous media, which do not completely mimic the micro environment provided by the DNA structure and its complexes with proteins. Thus, it is also important to evaluate the photogeneration of nucleoside-based radicals in nonaqueous media. The attention here is focused on the independent generation of 5,6-dihydropyrimidin-5-yl radicals in organic…
The staminal lever mechanism in Salvia L. (Lamiaceae): a key innovation for adaptive radiation?
2004
Abstract Floral key innovations play a significant role in the discussion of adaptive radiation in plants. The paper brings together a brief review of morphological key innovations in plants, elucidating their evolutionary significance in flower–pollinator interactions, and new data on Salvia, a genus being examined as an example for presumed adaptive radiation. We hypothesize that the characteristic staminal lever mechanism functions as a key innovation. It is defined as a functional unit including the modification of stamens to lever-like structures, their reversible movement, and the organization of the remaining floral structures involved in the process of pollen transfer. We follow the…
Effects of ultraviolet light on immune parameters of the roach
2000
Ultraviolet B radiation penetrates into water and can affect fish health and the immune system, as is the case with mammals. Teleost fish, the roach, were exposed to UVB irradiation in aquariums and a panel of immune parameters was determined. In addition to altered blood picture and respiratory burst by blood leukocytes, changes were noted also in major lymphatic organs. Respiratory burst and natural cytotoxicity activity of head kidney granulocytes and mitogen-activated proliferation of splenic lymphocytes were suppressed. Although mostly transitory, some parameters remained suppressed for the following 2 weeks. Ultraviolet A radiation had only minor effects. The stress induced by UVB may…