scholarly journals X-Ray Single-Grating Interferometry for Wavefront Measurement and Correction of Hard X-Ray Nanofocusing Mirrors

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7356
Author(s):  
Jumpei Yamada ◽  
Takato Inoue ◽  
Nami Nakamura ◽  
Takashi Kameshima ◽  
Kazuto Yamauchi ◽  
...  
Keyword(s):  
Root Mean Square ◽  
Numerical Aperture ◽  
Systematic Errors ◽  
Mean Square ◽  
Deposition Technique ◽  
X Ray ◽  
Wavefront Measurement ◽  
Alignment Errors

X-ray single-grating interferometry was applied to conduct accurate wavefront corrections for hard X-ray nanofocusing mirrors. Systematic errors in the interferometer, originating from a grating, a detector, and alignment errors of the components, were carefully examined. Based on the measured wavefront errors, the mirror shapes were directly corrected using a differential deposition technique. The corrected X-ray focusing mirrors with a numerical aperture of 0.01 attained two-dimensionally diffraction-limited performance. The results of the correction indicate that the uncertainty of the wavefront measurement was less than λ/72 in root-mean-square value.

Global Climate Model Performance over Alaska and Greenland

2008 ◽  
Vol 21 (23) ◽  
pp. 6156-6174 ◽  
Author(s):  
John E. Walsh ◽  
William L. Chapman ◽  
Vladimir Romanovsky ◽  
Jens H. Christensen ◽  
Martin Stendel
Keyword(s):  
Sea Level ◽  
Root Mean Square ◽  
Global Climate ◽  
Systematic Errors ◽  
The Arctic ◽  
Future Climate Change ◽  
Mean Square ◽  
Sea Level Pressure ◽  
Level Pressure ◽  
Mean Square Errors

Abstract The performance of a set of 15 global climate models used in the Coupled Model Intercomparison Project is evaluated for Alaska and Greenland, and compared with the performance over broader pan-Arctic and Northern Hemisphere extratropical domains. Root-mean-square errors relative to the 1958–2000 climatology of the 40-yr ECMWF Re-Analysis (ERA-40) are summed over the seasonal cycles of three variables: surface air temperature, precipitation, and sea level pressure. The specific models that perform best over the larger domains tend to be the ones that perform best over Alaska and Greenland. The rankings of the models are largely unchanged when the bias of each model’s climatological annual mean is removed prior to the error calculation for the individual models. The annual mean biases typically account for about half of the models’ root-mean-square errors. However, the root-mean-square errors of the models are generally much larger than the biases of the composite output, indicating that the systematic errors differ considerably among the models. There is a tendency for the models with smaller errors to simulate a larger greenhouse warming over the Arctic, as well as larger increases of Arctic precipitation and decreases of Arctic sea level pressure, when greenhouse gas concentrations are increased. Because several models have substantially smaller systematic errors than the other models, the differences in greenhouse projections imply that the choice of a subset of models may offer a viable approach to narrowing the uncertainty and obtaining more robust estimates of future climate change in regions such as Alaska, Greenland, and the broader Arctic.

scholarly journals A minimal time-scale for the spectral states of GX 339−4

2020 ◽  
Vol 499 (2) ◽  
pp. 2513-2522
Author(s):  
E Sonbas ◽  
K Mohamed ◽  
K S Dhuga ◽  
A Tuncer ◽  
E Göğüş
Keyword(s):  
Black Hole ◽  
Root Mean Square ◽  
Time Scale ◽  
Power Spectra ◽  
Mean Square ◽  
X Ray ◽  
Minimal Time ◽  
Power Spectral ◽  
Power Spectral Densities ◽  
Spectral States

ABSTRACT Black hole transients are known to undergo spectral transitions that form q-shaped tracks on a hardness intensity diagram. In this work, we use the archival Rossi X-ray Timing Explorer data to extract a characteristic minimal time-scale for the spectral states in GX 339−4 for the 2002–2003 and 2010 outbursts. We use the extracted time-scale to construct an intensity variability diagram for each outburst. This new diagram is comparable to the traditional hardness intensity diagram and offers the potential for probing the underlying dynamics associated with the evolution of the relevant emission regions in black hole transients. We confirm this possibility by connecting the minimal time-scale with the inner disc radius, Rin (estimated from spectral fits), and demonstrate a positive correlation between these variables as the system evolves through its spectral transitions. Furthermore, we probe the relation between the minimal time-scale and the break frequencies extracted from the power spectral densities. Lastly, we examine a possible link between the extracted time-scale and a traditional measure of variability, i.e. the root mean square, determined directly from the power spectra.

Travel-time errors in the laterally inhomogeneous earth

1971 ◽  
Vol 61 (6) ◽  
pp. 1639-1654 ◽  
Author(s):  
Cinna Lomnitz
Keyword(s):  
Travel Time ◽  
Root Mean Square ◽  
Time Estimation ◽  
Systematic Errors ◽  
Least Square ◽  
Travel Time Estimation ◽  
Mean Square ◽  
Travel Times ◽  
The Earth ◽  
Lateral Inhomogeneity

abstract Travel times from earthquakes or explosions contain both positive and negative systematic errors. Positive skews in travel-time residuals due to epicenter mislocation, and negative skews due to lateral inhomogeneity in the Earth, are analyzed. Methods for travel-time estimation are critically reviewed. Recent travel-time tables, including the J-B tables, are within the range of root-mean-square travel-time fluctuations; the J-B tables are systematically late but cannot be reliably improved by least-square methods. Effects of lateral inhomogeneity at teleseismic distances can be estimated by chronoidal methods independently of standard tables, but the available explosion data are insufficiently well-distributed in azimuth and distance for this purpose.

Structures of trans-[PtCl2(PBz3)2], trans-[PtI2(PBz3)2], trans-[Pt(NCS)2(PBz3)2]·0.5C6H6 and trans-[PdI2(PBz3)2]

2002 ◽  
Vol 58 (2) ◽  
pp. 244-250 ◽  
Author(s):  
Maria H. Johansson ◽  
Stefanus Otto ◽  
Åke Oskarsson
Keyword(s):  
Root Mean Square ◽  
Mean Square ◽  
X Ray ◽  
X Ray Crystallography ◽  
Normal Probability ◽  
Probability Plots ◽  
Coordination Plane

A series of structures of trans-[MX 2(PBz3)2] [M = Pt, X = Cl−; PBz3 = tribenzylphosphine (1), I−, trans-diiodobis(tribenzylphosphine)platinum(II) (2), and NCS−, trans-di(thiocyanate)bis(tribenzylphosphine)platinum(II) (3); M = Pd, X = I−, trans-diiodobis(tribenzylphosphine)palladium(II) (4)] have been characterized by X-ray crystallography. In all compounds each tribenzylphosphine has one benzylcarbon close to the coordination plane. In (1), (2) and (4) those (in-plane) C atoms, from the two different PBz3, exhibit an anti conformation along the P—P axis, while (3) has the gauche conformation. Root mean square (RMS) calculations and half-normal probability plots show that the complexes in (2) and (4) are very similar and the only significant differences between them are the M—P bonds, 2.354 (4) and 2.330 (5) Å, and the M—I bond distances, 2.604 (1) and 2.611 (2) Å, for Pd and Pt, respectively. Calculations of the steric demand of the PBz3 ligands based on the Tolman model gave values ranging from 155 to 178° for the effective and 156 to 179° for the Tolman angles, respectively.

Spectral Sensitivities of X-Ray Diffraction to the Roughness of Si/SiO2 Interfaces

1995 ◽  
Vol 399 ◽  
Author(s):  
K.W. Evans-Lutterodt ◽  
Mau-Tsu Tang
Keyword(s):  
Momentum Transfer ◽  
Root Mean Square ◽  
Spectral Distribution ◽  
Root Mean Square Roughness ◽  
Mean Square ◽  
X Ray Diffraction ◽  
X Ray ◽  
Interface Fluctuations

ABSTRACTResults from X-ray diffraction studies of the morphology of the growing Si(001 )/SiO2 interface are presented. We show the evolution of the root mean square roughness as a function of the growth variables, and we try to go beyond the root mean square parametrization of the interface by measuring the spectral distribution of interface fluctuations. Within our current experimental sensitivies we cannot resolve any fluctuations with a finite in-plane momentum transfer.

scholarly journals Systematic Errors in Double Star Observations

1992 ◽  
Vol 135 ◽  
pp. 311-313 ◽  
Author(s):  
Geoffrey G. Douglass ◽  
Charles E. Worley
Keyword(s):  
Root Mean Square ◽  
Proximity Effect ◽  
Position Angle ◽  
Systematic Errors ◽  
Double Star ◽  
Mean Square ◽  
Double Stars ◽  
Visual Double Stars ◽  
Systematic Effects

AbstractWe have examined the visual and speckle observations of visual double stars made by 31 experienced observers in order to evaluate possible systematic errors in these series. Using 57 “definitive” orbits, we find no appreciable errors in position angle. We do find systematic effects in separation for some observers, and, in particular, a “proximity” effect for measurements of pairs closer than 0″.5.Root-mean-square residuals are:

A refinement of the crystal structures of K2ReCl6, K2ReBr6, and K2PtBr6

1970 ◽  
Vol 48 (7) ◽  
pp. 1151-1154 ◽  
Author(s):  
H. D. Grundy ◽  
I. D. Brown
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Root Mean Square ◽  
Mean Square ◽  
X Ray ◽  
Bond Lengths ◽  
Using Data

The crystal structures of K2ReCl6, K2ReBr6, and K2PtBr6 have been refined using data collected on a single-crystal X-ray diffractometer to give weighted agreement indices ranging from 0.026 to 0.054 for 75 to 90 nonequivalent reflections. The following bond lengths were obtained: Re—Cl = 235 pm, Re—Br = 248 pm, Pt—Br = 246 pm, K—Cl = 348 pm, and K—Br = 367 and 364 pm in the Re and Pt compounds, respectively. The differences in the root-mean-square angles of libration of the MX62− ions in these and a number of isomorphous crystals are discussed.

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