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Very High Values (very + high_value)
Selected AbstractsElectromagnetically coupled microstrip square ring resonator: Inset/offset feed variation effects on resonance frequencyMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2006H. Ghanbari Abstract Inset/offset feed dependant variation of electromagnetically coupled (EMC) microstrip square ring resonator (MSRR) indicates overall increase in resonance frequency (fy). Based on experimental results an equation is suggested to determine fy. Very high values of quality factor (Q = 618) are obtained at two offset points near the ring edge, with VSWR , 1. This advantage of EMC-MSRR could be used for applications such as frequency-selective circuits and sensors. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1922,1924, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21815 [source] Influence of substrate temperature on the properties of electron beam evaporated ZnSe filmsCRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2010M. G. Syed Basheer Ahamed Abstract ZnSe films were deposited on glass substrates keeping the substrate temperatures, at room temperature (RT), 75, 150 and 250 °C. The films have exhibited cubic structure oriented along the (111) direction. Both the crystallinity and the grain size increased with increasing deposition temperature. A very high value of absorption co-efficient (104 cm -1) is observed. The band gap values decrease from a value of 2.94 eV to 2.69 eV with increasing substrate temperature. The average refractive index value is in the range of 2.39 , 2.41 for the films deposited at different substrate temperatures. The conductivity values increases continuously with temperature. Laser Raman spectra showed peaks at 140.8 cm -1, 246.7 cm -1and 204.5 cm -1which are attributable to 2TA LO phonon and TO phonon respectively. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Enhanced Permeability and Dielectric Constant of NiZn Ferrite Synthesized in Nanocrystalline Form by a Combustion MethodJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 5 2007Sasanka Deka The performance parameters of Ni0.5Zn0.5Fe2O4, synthesized in the nanocrystalline form by an autocombustion method, have been investigated. The sample sintered at 1200°C, with Bi2O3 as additive shows a very high value of initial permeability ,,i of >400 at 1 MHz, with low loss. Similarly, a very high dielectric constant is obtained at lower frequencies. The results show that optimum magnetic and electrical properties can be achieved for the NiZn ferrite nanocrystalline powders synthesized by the present autocombustion method and sintered at a relatively lower temperature of 1200°C when compared with a temperature of 1400°C required for the materials synthesized by the conventional ceramic method. [source] Global properties of the rich cluster ABCG 209 at z, 0.2. Spectroscopic and photometric catalogueMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2008A. Mercurio ABSTRACT This paper is aimed at giving an overview of the global properties of the rich cluster of galaxies ABCG 209. This is achieved by complementing the already available data with new medium-resolution spectroscopy and near-infrared (NIR) photometry which allow us to (i) analyse in detail the cluster dynamics, distinguishing among galaxies belonging to different substructures and deriving their individual velocity distributions, using a total sample of 148 galaxies in the cluster region, of which 134 belonging to the cluster; (ii) derive the cluster NIR luminosity function; (iii) study the Kormendy relation and the photometric plane of cluster early-type galaxies (ETGs). Finally we provide an extensive photometric (optical and NIR) and spectroscopic data set for such a complex system to be used in further analyses investigating the nature, formation and evolution of rich clusters of galaxies. The present study shows that the cluster is characterized by a very high value of the line-of-sight velocity dispersion: ,v= 1268+93,84 km s,1, that results in a virial mass of Mvir= 2.95+0.80,0.78× 1015 h,170 M, within Rvir= 3.42 h,170 Mpc. The analysis of the velocity dispersion profile shows that such high value of ,v is already reached in the central cluster region. There is evidence of three significant substructures, the primary one having a velocity dispersion of ,v= 847+52,49 km s,1, which makes it consistent with mass estimates from weak lensing analyses. This observational scenario confirms that ABCG 209 is presently undergoing strong dynamical evolution with the merging of two or more subclumps. This interpretation is also supported by the detection of a radio halo suggesting that there is a recent or ongoing merging. Cluster ETGs follow a Kormendy relation whose slope is consistent with previous studies both at optical and NIR wavelengths. We investigate the origin of the intrinsic scatter of the photometric plane due to trends of stellar populations, using line indices as indicators of age, metallicity and ,/Fe enhancement. We find that the chemical evolution of galaxies could be responsible for the intrinsic dispersion of the photometric plane. [source] Estimation of trends in high urban ozone levels using the quantiles of (GEV)ENVIRONMETRICS, Issue 5 2010Hortensia J. Reyes Abstract In this paper we propose a statistical methodology to analyze the trends of very high values of tropospheric ozone. The methodology is based on the estimation of percentiles of the distribution of extreme values. The asymptotic distribution of the estimated percentiles is obtained with a normal result. This allows us to use a linear regression to investigate linear and non-linear trends. To illustrate the proposed methodology we use the information on ozone levels from some monitoring stations in Mexico City during the period from 1986 to 2005. The analysis of the information indicates a decrease in the very high ozone levels in the later years. Copyright © 2009 John Wiley & Sons, Ltd. [source] Terahertz Time Domain Spectroscopy to Detect Low-Frequency Vibrations of Double-Walled Carbon NanotubesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 27 2010Sunil Kumar Abstract We have measured the frequency-dependent real index of refraction and extinction coefficient (and hence the complex dielectric function) of a free-standing double-walled carbon nanotube film of thickness 200 nm by using terahertz time domain spectroscopy in the frequency range 0.1 to 2.5 THz. The real index of refraction and extinction coefficient have very high values of approximately 52 and 35, respectively, at 0.1 THz, which decrease at higher frequencies. Two low-frequency phonon modes of the carbon nanotubes at 0.45 and 0.75 THz were clearly observed for the first time in the real and imaginary parts of the complex dielectric function along with a broad resonance centred at around 1.45 THz, the latter being similar to that in single-walled carbon nanotubes assigned to electronic excitations. Our experiments bring out a possible application of double-walled carbon nanotube films as a neutral density filter in the THz range. [source] On the general dynamic model of oceanic island biogeographyJOURNAL OF BIOGEOGRAPHY, Issue 6 2009Simone Fattorini Abstract Aim, To investigate the biological meaning of equations used to apply the general dynamic model (GDM) of oceanic island biogeography proposed by R. J. Whittaker, K. A. Triantis and R. J. Ladle. Location, Analyses are presented for 17 animal groups living on the Aeolian Islands, a volcanic archipelago in the central Mediterranean, near Sicily. Methods, In addition to the mathematical implementation of the GDM proposed by Whittaker, Triantis and Ladle, and termed here logATT2 (, where S is species number or any other diversity metric, t is island age, A is island area, and a, b, c and d are fitted parameters), a new implementation based on the Arrhenius equation of the species,area relationship (SAR) is investigated. The new model (termed powerATT2) is: . For logATT2 and powerATT2 models, equations were developed to calculate (1) the expected number of species at equilibrium (i.e. when the island has reached maturity) per unit area (Seq), and (2) the time required to obtain this value (teq). Whereas the intercept in the Gleason model (S = C + z log A) or the coefficient of the Arrhenius power model (S = CAz) of the SAR can be considered measures of the expected number of species per unit area, this is not the case for the parameter a of the ATT2 models. However, values of Seq can be used for this purpose. The index of ,colonization ability' (CAB), calculated as the ratio , may provide a measure of the mean number of species added per unit area per unit time. Results, Both ATT2 models fitted most of the data well, but the powerATT2 model was in most cases superior. Equilibrial values of species richness (Seq) varied from c. 3 species km,2 (reptiles) to 100 species km,2 (mites). The fitted curves for the powerATT2 model showed large variations in d, from 0.03 to 3. However, most groups had values of d around 0.2,0.4, as commonly observed for the z -values of SARs modelled by a power function. Equilibration times ranged from about 170,000 years to 400,000 years. Mites and springtails had very high values of CAB, thus adding many more species per unit area per unit time than others. Reptiles and phytophagous scarabs showed very low values, being the groups that added fewest species per unit area per unit time. Main conclusions, Values of equilibrial species richness per unit area are influenced by species biology (e.g. body size and ecological specialization). Theoretical and empirical evidence suggests that higher immigration rates should increase the z -values of the Arrhenius model. Thus, in the same archipelago, groups with larger z -values should be characterized by higher dispersal ability. Results obtained here for the parameter d conform to this prediction. [source] Validity and responsiveness of the Osnabrück Hand Eczema Severity Index (OHSI): a methodological studyBRITISH JOURNAL OF DERMATOLOGY, Issue 1 2009M. Dulon Summary Background, The Osnabrück Hand Eczema Severity Index (OHSI) is a scoring system for the assessment of the severity of hand eczema (HE). Objective, To assess the clinimetric value of the OHSI and to validate the longitudinal responsiveness of the OHSI using the Manuscore as a gold standard. Methods, OHSI and Manuscore scores were compared before and after 3 weeks' inpatient treatment of 62 patients with occupational HE. Correlation coefficients and 95% limits of agreement were calculated and the ability of OHSI to identify severe HE was analysed. The responsiveness of the OHSI in monitoring skin changes over time was evaluated by calculating effect sizes. Results, High correlation was found between the OHSI and Manuscore at both scoring occasions (around rs = 0·77). Differences between both measurements were within the 95% limits of agreement for 94% of patients, with a tendency for the OHSI to underestimate the severity at very low and at very high values compared with the Manuscore. Responsiveness to change was good. Both instruments showed significant improvement between the scoring occasions. Using the OHSI values, the proportion of classification to the correct tertile of score change was 69%. Effect size from untreated to treated was 0·6 for the Manuscore and 1·1 for the OHSI, with higher effect sizes in individuals with severe HE. Conclusions, Even though the OHSI allows less differentiation than the Manuscore, it shows adequate validity and responsiveness to change. Thus the OHSI is suitable for both monitoring the severity of HE and the effects of treatment. [source] | ||||||||||