Revised and extended analysis of Cd IV

1980 ◽  
Vol 58 (6) ◽  
pp. 737-743 ◽  
Author(s):  
Y. N. Joshi ◽  
Th. A. M. van Kleef ◽  
M. Mazzoni
Keyword(s):  
Normal Incidence ◽  
Extended Analysis

The spectrum of cadmium was photographed in the region 500–2100 Å using a 10.7 m normal incidence spectrograph and a 6.65 m normal incidence spectrograph. The sources used were a triggered spark and a sliding spark. The earlier analysis has been revised and extended. All levels of the 4d85s and 4d85p configurations have been determined. Parametric level fitting calculations support the analysis. Three hundred and seventeen lines have been classified in this spectrum of which 209 are new lines.

Revised and extended analysis of the 3d10nl configurations in As V, Se VI, and Br VII

1986 ◽  
Vol 64 (3) ◽  
pp. 330-333 ◽  
Author(s):  
Y. N. Joshi ◽  
Th. A. M. Van Kleef
Keyword(s):  
Wavelength Region ◽  
Normal Incidence ◽  
Extended Analysis

The spectra of arsenic, selenium, and bromine were photographed in the wavelength region 450–2000 Å on 6.65- and 3-m normal-incidence spectrographs using a triggered spark source. The new observations have led us to revise and extend the As V, Se VI, and Br VII spectra.

Analysis of Contrast Reversal in SEM Images

1972 ◽  
Vol 30 ◽  
pp. 398-399
Author(s):  
M. D. Coutts ◽  
E. R. Levin
Keyword(s):  
Incident Beam ◽  
Normal Incidence ◽  
Beam Current ◽  
Secondary Emission ◽  
Image Contrast ◽  
Sem Images ◽  
Secondary Electrons ◽  
Image Position

On tilting samples in an SEM, the image contrast between two elements, x and y often decreases to zero at θε, which we call the no-contrast angle. At angles above θε the contrast is reversed, θ being the angle between the specimen normal and the incident beam. The available contrast between two elements, x and y, in the SEM can be defined as,(1)where ix and iy are the total number of reflected and secondary electrons, leaving x and y respectively. It can easily be shown that for the element x,(2)where ib is the beam current, isp the specimen absorbed current, δo the secondary emission at normal incidence, k is a constant, and m the reflected electron coefficient.

Characterization of Rh/Si multilayer structure by HREM and HAADF

1992 ◽  
Vol 50 (1) ◽  
pp. 122-123
Author(s):  
Y. Cheng ◽  
J. Liu ◽  
M.B. Stearns ◽  
D.G. Steams
Keyword(s):  
Normal Incidence ◽  
High Resolution Electron Microscopy ◽  
X Rays ◽  
Beam Direction ◽  
Cross Sectional ◽  
Optical Elements ◽  
Resolution Electron ◽  
Point To Point ◽  
Better Than

The Rh/Si multilayer (ML) thin films are promising optical elements for soft x-rays since they have a calculated normal incidence reflectivity of ∼60% at a x-ray wavelength of ∼13 nm. However, a reflectivity of only 28% has been attained to date for ML fabricated by dc magnetron sputtering. In order to determine the cause of this degraded reflectivity the microstructure of this ML was examined on cross-sectional specimens with two high-resolution electron microscopy (HREM and HAADF) techniques.Cross-sectional specimens were made from an as-prepared ML sample and from the same ML annealed at 298 °C for 1 and 100 hours. The specimens were imaged using a JEM-4000EX TEM operating at 400 kV with a point-to-point resolution of better than 0.17 nm. The specimens were viewed along Si [110] projection of the substrate, with the (001) Si surface plane parallel to the beam direction.

On resolving fine periodic microstructures in the optical microscope

1989 ◽  
Vol 47 ◽  
pp. 364-365
Author(s):  
W.S. Putnam ◽  
C. Viney
Keyword(s):  
Liquid Crystalline ◽  
Numerical Aperture ◽  
Polarized Light ◽  
Normal Incidence ◽  
Optical Microscope ◽  
Angle Of Incidence ◽  
Resolution Limit ◽  
Crystalline Materials ◽  
Periodic Microstructures ◽  
Liquid Crystalline Materials

Many sheared liquid crystalline materials (fibers, films and moldings) exhibit a fine banded microstructure when observed in the polarized light microscope. In some cases, for example Kevlar® fiber, the periodicity is close to the resolution limit of even the highest numerical aperture objectives. The periodic microstructure reflects a non-uniform alignment of the constituent molecules, and consequently is an indication that the mechanical properties will be less than optimal. Thus it is necessary to obtain quality micrographs for characterization, which in turn requires that fine detail should contribute significantly to image formation.It is textbook knowledge that the resolution achievable with a given microscope objective (numerical aperture NA) and a given wavelength of light (λ) increases as the angle of incidence of light at the specimen surface is increased. Stated in terms of the Abbe resolution criterion, resolution improves from λ/NA to λ/2NA with increasing departure from normal incidence.

Microspectroscopy Using a Solid Immersion Lens

2001 ◽  
Vol 7 (S2) ◽  
pp. 148-149
Author(s):  
C.D. Poweleit ◽  
J Menéndez
Keyword(s):  
Spatial Resolution ◽  
Focal Plane ◽  
Numerical Aperture ◽  
Normal Incidence ◽  
Spot Size ◽  
Index Of Refraction ◽  
Objective Lens ◽  
Improvement Factor ◽  
Oil Immersion ◽  
Long Time

Oil immersion lenses have been used in optical microscopy for a long time. The light’s wavelength is decreased by the oil’s index of refraction n and this reduces the minimum spot size. Additionally, the oil medium allows a larger collection angle, thereby increasing the numerical aperture. The SIL is based on the same principle, but offers more flexibility because the higher index material is solid. in particular, SILs can be deployed in cryogenic environments. Using a hemispherical glass the spatial resolution is improved by a factor n with respect to the resolution obtained with the microscope’s objective lens alone. The improvement factor is equal to n2 for truncated spheres.As shown in Fig. 1, the hemisphere SIL is in contact with the sample and does not affect the position of the focal plane. The focused rays from the objective strike the lens at normal incidence, so that no refraction takes place.

SOFT X-RAY IMAGES OF THE SOLAR CORONA USING NORMAL INCIDENCE OPTICS

1988 ◽  
Vol 49 (C1) ◽  
pp. C1-115-C1-118 ◽  
Author(s):  
M. E. BRUNER ◽  
B. M. HAISCH ◽  
W. A. BROWN ◽  
L. W. ACTON ◽  
J. H. UNDERWOOD
Keyword(s):  
Solar Corona ◽  
Normal Incidence ◽  
X Ray

Behavioral activity during prolonged hypoxemia in fetal sheep

1988 ◽  
Vol 65 (6) ◽  
pp. 2420-2426 ◽  
Author(s):  
A. D. Bocking ◽  
R. Gagnon ◽  
K. M. Milne ◽  
S. E. White
Keyword(s):  
Blood Flow ◽  
Eye Movements ◽  
Normal Incidence ◽  
Behavioral Activity ◽  
Uterine Blood Flow ◽  
Fetal Sheep ◽  
Pregnant Sheep ◽  
Fetal Breathing ◽  
Fetal Breathing Movements ◽  
Internal Iliac

Experiments were conducted in unanesthetized, chronically catheterized pregnant sheep to determine the fetal behavioral response to prolonged hypoxemia produced by restricting uterine blood flow. Uterine blood flow was reduced by adjusting a vascular occluder placed around the maternal common internal iliac artery to decrease fetal arterial O2 content from 6.1 +/- 0.3 to 4.1 +/- 0.3 ml/dl for 48 h. Associated with the decrease in fetal O2 content, there was a slight increase in fetal arterial PCO2 and decrease in pH, which were both transient. There was an initial inhibition of both fetal breathing movements and eye movements but no change in the pattern of electrocortical activity. After this initial inhibition there was a return to normal incidence of both fetal breathing movements and eye movements by 16 h of the prolonged hypoxemia. These studies indicate that the chronically catheterized sheep fetus is able to adapt behaviorally to a prolonged decrease in arterial O2 content secondary to the restriction of uterine blood flow.

Auditor Tenure and the Timeliness of Misstatement Discovery

2017 ◽  
Vol 93 (2) ◽  
pp. 315-338 ◽  
Author(s):  
Zvi Singer ◽  
Jing Zhang
Keyword(s):  
Natural Experiment ◽  
Audit Quality ◽  
Client Engagement ◽  
Audit Firm ◽  
Auditor Tenure ◽  
Sarbanes Oxley ◽  
Auditor Change ◽  
Negative Effect ◽  
Extended Analysis ◽  
Arthur Andersen

ABSTRACT Using the timeliness of misstatement discovery as a proxy for audit quality, we examine the association between audit firm tenure and audit quality in a setting that alleviates the endogeneity problem endemic to this line of research. We find that longer audit firm tenure leads to less timely discovery and correction of misstatements, which is consistent with a negative effect of long auditor tenure on audit quality. In addition, using the non-voluntary auditor change following the demise of Arthur Andersen in 2002 as a natural experiment, we show that the misstatements of its former clients were discovered faster than those of comparable companies that retained their auditors throughout the misstatement. This finding speaks to the benefit of a fresh look by a new auditor. An extended analysis shows that longer auditor tenure also leads to misstatements of greater magnitudes, and that the Sarbanes-Oxley Act has mitigated, but not eliminated, the negative effect of long auditor tenure. Last, we show that the negative association between auditor tenure and timely discovery of misstatements is mainly present in the first ten years of an audit engagement. Our study has implications for regulators who continue to express concern regarding lengthy auditor-client engagement. JEL Classifications: K22; K23; L51; M41; M42; M48.

Sign in / Sign up

Export Citation Format

Share Document