Line broadening by focusing

1984 ◽  
Vol 62 (7) ◽  
pp. 661-668 ◽  
Author(s):  
Adelsindo Liberato de Brito ◽  
Arthur Jabs
Keyword(s):  
Light Beam ◽  
Ad Hoc ◽  
Incident Light ◽  
Wave Theory ◽  
Spectral Width ◽  
Line Broadening ◽  
Classical Wave ◽  
Gas Ionization ◽  
The Mean ◽  
Quantitative Formula

We point out that the spectral width of a quasimonochromatic light beam broadens when the beam is focused. A quantitative formula for this broadening is derived from classical wave theory. The effect is shown to explain some experiments on laser beams done by Panarella which he explained using the ad hoc hypothesis that the frequency of the photons changes along with the intensity of the light beam. The line broadening by focusing might also contribute to gas ionization by incident light when the ionization potential is well above the mean photon energy. Remarks are made on some direct applications of the Heisenberg relations in comparison with our treatment.

Gas ionization by focused laser beams

1984 ◽  
Vol 62 (10) ◽  
pp. 1010-1013 ◽  
Author(s):  
A. L. de Brito
Keyword(s):  
Laser Radiation ◽  
Photon Energy ◽  
Ionization Energy ◽  
Laser Beams ◽  
Line Broadening ◽  
Gas Ionization ◽  
The Mean ◽  
Gas Molecules ◽  
Focused Laser Beams

It is shown that the effect of line broadening by focusing may contribute considerably to the observed laser-induced ionization of gases even when the ionization energy of the gas molecules is well above the mean photon energy of the laser radiation.

scholarly journals Technical note: Inherent benchmark or not? Comparing Nash–Sutcliffe and Kling–Gupta efficiency scores

2019 ◽  
Vol 23 (10) ◽  
pp. 4323-4331 ◽  
Author(s):  
Wouter J. M. Knoben ◽  
Jim E. Freer ◽  
Ross A. Woods
Keyword(s):  
Time Series ◽  
Coefficient Of Variation ◽  
Ad Hoc ◽  
Model Performance ◽  
Technical Note ◽  
Mean Flow ◽  
Model Adequacy ◽  
Robust Model ◽  
The Mean ◽  
Adequacy Assessment

Abstract. A traditional metric used in hydrology to summarize model performance is the Nash–Sutcliffe efficiency (NSE). Increasingly an alternative metric, the Kling–Gupta efficiency (KGE), is used instead. When NSE is used, NSE = 0 corresponds to using the mean flow as a benchmark predictor. The same reasoning is applied in various studies that use KGE as a metric: negative KGE values are viewed as bad model performance, and only positive values are seen as good model performance. Here we show that using the mean flow as a predictor does not result in KGE = 0, but instead KGE =1-√2≈-0.41. Thus, KGE values greater than −0.41 indicate that a model improves upon the mean flow benchmark – even if the model's KGE value is negative. NSE and KGE values cannot be directly compared, because their relationship is non-unique and depends in part on the coefficient of variation of the observed time series. Therefore, modellers who use the KGE metric should not let their understanding of NSE values guide them in interpreting KGE values and instead develop new understanding based on the constitutive parts of the KGE metric and the explicit use of benchmark values to compare KGE scores against. More generally, a strong case can be made for moving away from ad hoc use of aggregated efficiency metrics and towards a framework based on purpose-dependent evaluation metrics and benchmarks that allows for more robust model adequacy assessment.

scholarly journals How Does the Cause of Infantile Hemiparesis Influence Other Conditioning Factors? A Preliminary Study in a Spanish Population

Children ◽  
2021 ◽  
Vol 8 (5) ◽  
pp. 323
Author(s):  
Rocío Palomo-Carrión ◽  
Rita Pilar Romero-Galisteo ◽  
Helena Romay-Barrero ◽  
Inés Martínez-Galán ◽  
Cristina Lirio-Romero ◽  
...  
Keyword(s):  
Ad Hoc ◽  
Cross Sectional Study ◽  
Motor Dysfunction ◽  
Sensory Loss ◽  
Speech Impairments ◽  
Cross Sectional ◽  
Conditioning Factors ◽  
Age Of Diagnosis ◽  
The Mean ◽  
Preliminary Study

Infantile hemiparesis may be associated with significant morbidity and may have a profound impact on a child’s physical and social development. Infantile hemiparesis is associated with motor dysfunction as well as additional neurologic impairments, including sensory loss, mental retardation, epilepsy, and vision, hearing, or speech impairments. The objective of this study was to analyze the association between the cause of infantile hemiparesis and birth (gestational age), age of diagnosis, and associated disorders present in children with infantile hemiparesis aged 0 to 3 years. An observational and cross-sectional study was performed. A simple and anonymous questionnaire was created ad hoc for parents of children diagnosed with infantile hemiparesis aged between 0 and 3 years about the situation regarding the diagnosis of hemiparesis, birth, cause of hemiparesis, and presence of other associated disorders. Perinatal stroke (60.1%) was the most common cause of hemiparesis, and the most typical associated disorder was epilepsy (34.2%), with the second largest percentage in this dimension corresponding to an absence of associated disorders (20.7%). The most frequent birth was “no premature” (74.1%). The mean age of diagnosis of infantile hemiparesis was registered at 8 months (IQR: 0–36). Knowing the possible association between different conditioning factors and the cause of infantile hemiparesis facilitates the prevention of severe sequelae in children and family, implementing an early comprehensive therapeutic approach in children with infantile hemiparesis.

scholarly journals Upconversion of Broadband Infrared Radiation into Visible Light for Different Pumping Parameters

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Man Nen Litvinova ◽  
Victor Krishtop ◽  
Evgeniy Tolstov ◽  
Vladimir Troilin ◽  
Larisa Alekseeva ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Visible Light ◽  
Light Beam ◽  
Infrared Radiation ◽  
Spectral Width ◽  
Uniaxial Crystal ◽  
Phase Matching ◽  
Pump Radiation ◽  
Broadband Radiation ◽  
Lithium Niobate Crystals

The influence of pump radiation parameters such as the polarization and the spectral width of infrared radiation on the conversion of broadband radiation in lithium niobate crystals was investigated. The spectra of converted radiation were calculated for two types of phase matching in the negative uniaxial crystal by taking into account the convergence of the light beam in the crystal. Experimental spectra were obtained and compared with the calculated spectra.

The Use of the Pseudo-Voigt Function in the Variance Method of X-ray Line-Broadening Analysis

1997 ◽  
Vol 30 (4) ◽  
pp. 427-430 ◽  
Author(s):  
F. Sánchez-Bajo ◽  
F. L. Cumbrera
Keyword(s):  
Crystallite Size ◽  
Original Form ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Variance Method ◽  
The Mean ◽  
Voigt Function

A modified application of the variance method, using the pseudo-Voigt function as a good approximation to the X-ray diffraction profiles, is proposed in order to obtain microstructural quantities such as the mean crystallite size and root-mean-square (r.m.s.) strain. Whereas the variance method in its original form is applicable only to well separated reflections, this technique can be employed in the cases where there is line-profile overlap. Determination of the mean crystallite size and r.m.s. strain for several crystallographic directions in a nanocrystalline cubic sample of 9-YSZ (yttria-stabilized zirconia) has been performed by means of this procedure.

scholarly journals Curved Interference Pattern Created by Photons Behaving as Particle---Double Slit Experiment Still Has Much to Offer

2021 ◽  
Author(s):  
Hui Peng
Keyword(s):  
Interference Pattern ◽  
Wave Theory ◽  
Quantum Probability ◽  
The Novel ◽  
Physics First ◽  
Airy Beam ◽  
Comprehensive Information ◽  
Classical Wave ◽  
Double Slit Experiment ◽  
Double Slit

Abstract Young’s double slit experiments, which represent the mystery of quantum mechanics, have been described by either the classical wave, or quantum probability waves or pilot waves. Recently, the novel experiments show that the interference patterns of the double slit/cross-double slit experiments may be curved. The previous phenomena of the light bending contain the gravity bending and Airy beam curving transversely. The curved Airy beam is interpreted by the quantum Schrödinger’s wave equation and electromagnetic wave theory. To study the curved interference patterns of the comprehensive double slit experiments, we study the underlying physics first, namely, to study whether the light beam/photons behave as wave or as particle before forming the curved interference pattern. In this article, the comprehensive double slit experiments are performed, which show: (1) the fringes of the curved interference pattern are created independently and may be create partially; (2) the longitudinal shield and the metal tube inserted between the slide and the detector has no effect on the interference pattern. The experimental observations suggest that, before forming the curved interference pattern on the detector, photons behave as particles, which can be referred as “wave-particle-coexistence”. The phenomena provide the comprehensive information/data for the theoretical study.

scholarly journals The Use of the Baker Interference Microscope for the Study of Optically Heterogeneous Specimens

1956 ◽  
Vol s3-97 (40) ◽  
pp. 569-591
Author(s):  
R. C. FAUST
Keyword(s):  
Incident Light ◽  
Field Of View ◽  
Variation Method ◽  
Specimen Thickness ◽  
Immersion Liquid ◽  
Interference Microscope ◽  
Relative Index ◽  
The Third ◽  
Wavelength Variation ◽  
The Mean

The refractive index of an optically heterogeneous specimen will generally vary in directions parallel and normal to the microscope axis, but a mean index can be defined such that the optical thickness of the specimen is equal to the product of the mean index and the specimen thickness. If such a specimen is examined under an interference microscope, the fringe displacement will be zero at those parts of the specimen for which the mean index is equal to the index of the immersion liquid. Thus, by gradually changing the index of the liquid relative to that of the specimen, one can determine the manner in which the mean index varies from region to region of the specimen. In the present work these changes in relative index have been effected by varying either the wavelength of the incident light or the temperature of the system. The Baker two-beam interference microscope has been successfully used for such investigations. Three types of interference pattern have been tried: (i) a single fringe is made to fill the field of view and the intensity differences between the specimen and the background are studied; (ii) monochromatic fringes are formed in a quartz wedge and their linear displacements are examined; and (iii) a quartz plate is used, channelled spectra being produced by the spectrographic analysis of the interference colours. The first two types can be used with either the temperature or the wavelength variation method, but the third was specifically designed for use with the wavelength variation method. Although these experiments have mostly been carried out on birefringent fibres, the techniques are applicable to any kind of object. The attainable accuracy increases with specimen thickness; under favourable circumstances the index at any point of a specimen 10 µ thick should not be in error by more than †3x10-4

Report of Ad Hoc Committee on Vitamin D Methodology, AOAC

1975 ◽  
Vol 58 (2) ◽  
pp. 330-332
Author(s):  
Forrest W Quackenbush ◽  
Daniel Banes ◽  
Philip H Derse
Keyword(s):  
Maleic Anhydride ◽  
Chemical Method ◽  
Ad Hoc ◽  
Collaborative Study ◽  
Mean Values ◽  
Biological Tests ◽  
Aoac Official ◽  
The Mean ◽  
Biological Methods ◽  
Good Agreement

Abstract In a collaborative study 6 samples of vitamin D3 resins were analyzed chemically by 9 laboratories and tested biologically by 3 laboratories to determine whether there exists a discrepancy between chemical and biological methods of measuring potency of these materials. The chemical methods employed saponification with and without subsequent maleic anhydride treatment. The biological method was the AOAC official final action rat assay, 39.149–39.162. The results showed good agreement between laboratories in the chemical analysis and relatively poor agreement in the biological tests. However, based upon the mean values as reported by the different laboratories, the chemical method employing saponification alone consistently overestimated biopotency, whereas the chemical method including maleic anhydride treatment gave results which averaged much closer to the mean biopotency values. There was no evidence that maleic anhydride treatment reduced values significantly below biopotency values.

scholarly journals The molecular scattering of light in vapours and in liquids and its relation to the opalescence observed in the critical state

1922 ◽  
Vol 102 (715) ◽  
pp. 151-161 ◽  
Keyword(s):  
Critical Point ◽  
Critical State ◽  
Incident Light ◽  
Wave Length ◽  
Molecular Scattering ◽  
Avogadro’S Number ◽  
Quantitative Manner ◽  
The Mean ◽  
Good Agreement ◽  
Molecular Scattering Of Light

It has long been known that in the immediate vicinity of the critical state, many substances exhibit a strong and characteristic opalescence. In recent years, the phenomenon has been studied by Travers and Usher in the case of carefully purified CS 2 , SO 2 , and ether, by S. Young, by F. B. Young in the case of ether, and in a quantitative manner by Kammerlingh Onnes and Keesom in the case of ethylene. An explanation of the phenomenon on thermodynamic principles as due to the accidental deviations of density arising in the substance was put forward by Smoluchowski. He obtained an expression for the mean fluctuation of density in terms of the compressibility of the substance, and later, Einstein applied Maxwell’s equations of the electromagnetic field to obtain an expression for the intensity of the light scattered in consequence of such deviations of density. He showed that the fraction α of the incident energy scattered in the substance per unit volume is 8 π 3 /27 RT β ( μ 2 – 1) 2 ( μ 2 + 2) 2 /N λ 4 (1) In this, R and N are the gas constant and Avogadro’s number per grammolecule, β is the isothermal compressibility of the substance, μ is the refractive index and λ is the wave-length of the incident light. Keesom tested this formula over a range of 2·35° above the critical point of ethylene and found good agreement except very close to the critical point.

Patients’ experiences of remote communication after pacemaker implant

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
A Lopez-Villegas ◽  
D Catalan-Matamoros ◽  
K T Lappegard ◽  
S Peiro ◽  
R Lopez-Liria
Keyword(s):  
Remote Monitoring ◽  
Cost Reduction ◽  
Ad Hoc ◽  
Healthcare Services ◽  
Patient Experiences ◽  
Remote Communication ◽  
Patient Satisfaction Survey ◽  
The Mean ◽  
Baseline Characteristics

Abstract Background the concept of 'patient experience' has become central to how to improve healthcare. Remote communication with patients is today a frequent practice in healthcare services, showing similar outcomes to conventional monitoring at the hospital (CM) while enabling cost reduction in both formal and informal care. The purpose of this study was to analyse the experiences of people with remote monitoring (RM) of pacemakers. Methods Patients were randomly allocated to either the RM or CM. Using the 'Generic Short Patient Experiences Questionnaire' (GS-PEQ), as well as an ad-hoc survey from the 'telehealth patient satisfaction survey' and 'costs survey', patients' experiences were measured six months after the pacemaker implant in a cohort of 50 consecutive patients. The mean age was 74.8 (±11.75) years and 26 (52%) patients were male of which 1 was lost in follow-up. Differences in baseline characteristics between groups were not found. Results Findings showed overall positive and similar experiences in patients in both groups. Significant differences were found in GS-PEQ concerning how RM patients received less information about their diagnosis/ afflictions (p = 0.046). We did not find significant differences in other items such as 'confidence in the clinicians' professional skills', 'treatment perception adapted to their situation', 'involvement in decisions regarding the treatment', 'perception of hospital organisation', waiting before admission', 'satisfaction of help and treatment received', 'benefit received', and 'incorrect treatment'. Conclusions The remote communication of pacemakers was met with positive levels of patients' experiences similarly to patients in the CM group. However, patients included in RM group received less information. Thus, improving the quality and timing of information is required in RM group in the planning and organisation of future remote communication healthcare services for people living with a pacemaker implant. Key messages Patients included in both groups of follow-up showed similar levels in their experiences with the use of the pacemakers. It is necessary improving the quality and timing of information required in remote monitoring of users in the planning of future remote communication healthcare services for people with pacemaker.

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