SELECTIVE REFLECTION FROM MERCURY AND CADMIUM VAPORS

1950 ◽  
Vol 28a (2) ◽  
pp. 93-112 ◽  
Author(s):  
H. L. Welsh ◽  
J. Kastner ◽  
A. C. Lauriston
Keyword(s):  
Resonance Frequency ◽  
Oscillator Strength ◽  
Large Range ◽  
Incident Light ◽  
Selective Reflection ◽  
Residual Intensity ◽  
Order Of Magnitude ◽  
Low Pressures ◽  
The Relationship ◽  
Good Agreement

Selective reflection from mercury and cadmium vapors in the neighborhood of the resonance lines was investigated quantitatively using incident light of continuous spectral distribution. For a given experimental arrangement the lowest vapor density (atoms per cubic centimeter) at which selective reflection could be detected at Hg 2537 Å, Cd 2288 Å, and Cd 3261 Å was inversely proportional to the oscillator strength (f-value) of the absorption line. Contours of the selective reflection of the Hg 2537 Å and Cd 2288 Å lines were obtained over a large range of vapor densities up to 80 × 1018 atoms per cc. At this density the cadmium reflection extended over several thousand cm.−1 compared to about a hundred cm.−1 for mercury. The general features of the reflection contours can be explained by the theory of reflection from an absorbing medium. Fitting a theoretical curve to the experimental reflection contour yields values of the oscillator strength and the damping constant. For Hg 2537 Å and Cd 2288 Å the f-values are 0.0268 and 1.40 respectively, in good agreement with those found by other methods. The damping constant, γ, varies as the square root of the number of atoms per cubic centimeter, indicating that the mechanism of selective reflection is not the same as that for absorption and emission. An empirical areal law for selective reflection confirms the relationship [Formula: see text]. A shift of the resonance frequency of the order of magnitude of the coupling shift calculated by Weisskopf was observed for Hg 2537 Å. Deviations from theory at both high and low pressures were observed for Cd 2288 Å. The low pressure deviation takes the form of a line of residual intensity at the resonance frequency, which may be due to a different kind of selective reflection.

SELECTIVE REFLECTION FROM THE VAPORS OF THE ALKALI METALS

1951 ◽  
Vol 29 (3) ◽  
pp. 217-226 ◽  
Author(s):  
A. C. Lauriston ◽  
H. L. Welsh
Keyword(s):  
Alkali Metals ◽  
Incident Light ◽  
Steel Tube ◽  
Oscillator Strengths ◽  
Vapor Pressures ◽  
Selective Reflection ◽  
Sodium Potassium ◽  
Square Roots ◽  
Resonance Doublet ◽  
Good Agreement

Selective reflection from sodium, potassium, rubidium, and caesium vapors in the neighborhood of the resonance lines was observed for vapor pressures between 10 mm. and 1 atm., using a steel tube with a window of transparent magnesium oxide. Reflecting power as a function of frequency was measured by using incident light of continuous spectral distribution. The reflection contour for pressures up to ½ atm. is in good agreement with the theory of reflection from an absorbing medium. For each line the damping constant in the dispersion equations varies as the square root of the number of atoms per cubic centimeter, as was found previously for mercury and cadmium. For the two members of the resonance doublet the damping constants are proportional to the square roots of the oscillator strengths. In a region about 5 cm.−1 wide about each resonance frequency the reflected intensity measured experimentally is greater than that calculated. These lines of residual intensity may be due to a second kind of selective reflection. At pressures above ½ atm. the observed reflection contour cannot be explained by the simple anomalous dispersion theory.

Oscillator Strength Measurements in the Vacuum-Ultraviolet by the Emission Method

1988 ◽  
Vol 102 ◽  
pp. 353-356
Author(s):  
C. Goldbach ◽  
G. Nollez
Keyword(s):  
Oscillator Strength ◽  
Vacuum Ultraviolet ◽  
Oscillator Strengths ◽  
Emission Method ◽  
Absolute Scale ◽  
Good Agreement

AbstractThe principles and the realization of an experiment devoted to oscillator strength measurements in the vacuum-ultraviolet by the emission method are briefly presented. The results obtained for the strong multiplets of neutral nitrogen and carbon in the 1200-2000 Å range yield an absolute scale of oscillator strengths in good agreement with the most recent calculations.

Pound Wise and Penny Foolish? Weight Loss and The Dynamics of Health Care Spending

2011 ◽  
Vol 14 (2) ◽  
Author(s):  
Thomas G Koch
Keyword(s):  
Weight Loss ◽  
Cost Savings ◽  
Cost Effective ◽  
Economic Consequences ◽  
Health Care Spending ◽  
Order Of Magnitude ◽  
Dynamic Measures ◽  
The Cost ◽  
The Impact ◽  
The Relationship

Current estimates of obesity costs ignore the impact of future weight loss and gain, and may either over or underestimate economic consequences of weight loss. In light of this, I construct static and dynamic measures of medical costs associated with body mass index (BMI), to be balanced against the cost of one-time interventions. This study finds that ignoring the implications of weight loss and gain over time overstates the medical-cost savings of such interventions by an order of magnitude. When the relationship between spending and age is allowed to vary, weight-loss attempts appear to be cost-effective starting and ending with middle age. Some interventions recently proven to decrease weight may also be cost-effective.

scholarly journals Experimental studies on the transformation from firn to ice in the wet-snow zone of temperate glaciers

1997 ◽  
Vol 24 ◽  
pp. 181-185 ◽  
Author(s):  
Katsuhisa Kawashima ◽  
Tomomi Yamada
Keyword(s):  
Experimental Studies ◽  
Ice Formation ◽  
Compression Tests ◽  
Densification Rate ◽  
Overburden Pressure ◽  
Proportionality Constant ◽  
Wet Snow ◽  
Water Saturated ◽  
The Relationship ◽  
Good Agreement

The densification of water-saturated firn, which had formed just above the firn-ice transition in the wet-snow zone of temperate glaciers, was investigated by compression tests under pressures ranging from 0.036 to 0.173 MPa, with special reference to the relationship between densification rate, time and pressure. At each test, the logarithm of the densification rate was proportional to the logarithm of the time, and its proportionality constant increased exponentially with increasing pressure. The time necessary for ice formation in the firn aquifer was calculated using the empirical formula obtained from the tests. Consequently, the necessary time decreased exponentially as the pressure increased, which shows that the transformation from firn in ice can be completed within the period when the firn aquifer exists, if the overburden pressure acting on the water-saturated firn is above 0.12–0.14 MPa. This critical value of pressure was in good agreement with the overburden pressure obtained from depth–density curves of temperate glaciers. It was concluded that the depth of firn–ice transition was self-balanced by the overburden pressure to result in the concentration between 20 and 30 m.

scholarly journals Ultra-high-Q resonances in plasmonic metasurfaces

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
M. Saad Bin-Alam ◽  
Orad Reshef ◽  
Yaryna Mamchur ◽  
M. Zahirul Alam ◽  
Graham Carlow ◽  
...  
Keyword(s):  
Incident Light ◽  
Reducing Power ◽  
Field Enhancement ◽  
Plasmonic Nanostructures ◽  
High Q ◽  
Alternative Material ◽  
Order Of Magnitude ◽  
Wavelength Scale ◽  
Strong Confinement ◽  
Sub Wavelength

AbstractPlasmonic nanostructures hold promise for the realization of ultra-thin sub-wavelength devices, reducing power operating thresholds and enabling nonlinear optical functionality in metasurfaces. However, this promise is substantially undercut by absorption introduced by resistive losses, causing the metasurface community to turn away from plasmonics in favour of alternative material platforms (e.g., dielectrics) that provide weaker field enhancement, but more tolerable losses. Here, we report a plasmonic metasurface with a quality-factor (Q-factor) of 2340 in the telecommunication C band by exploiting surface lattice resonances (SLRs), exceeding the record by an order of magnitude. Additionally, we show that SLRs retain many of the same benefits as localized plasmonic resonances, such as field enhancement and strong confinement of light along the metal surface. Our results demonstrate that SLRs provide an exciting and unexplored method to tailor incident light fields, and could pave the way to flexible wavelength-scale devices for any optical resonating application.

scholarly journals 41Ca Concentrations in Modern Bone and Their Implications for Dating

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 305-310 ◽  
Author(s):  
Roy Middleton ◽  
David Fink ◽  
Jeffrey Klein ◽  
Pankaj Sharma
Keyword(s):  
Mass Spectrometry ◽  
Accelerator Mass Spectrometry ◽  
Isotope Enrichment ◽  
Terrestrial Rock ◽  
Order Of Magnitude ◽  
Cow Bone ◽  
Good Agreement

We have made the first measurements without pre-enrichment of 41Ca in terrestrial rock and bone samples using accelerator mass spectrometry. Although the results in tufa deposits from Egypt are in good agreement with the saturation value of 8×10-15 predicted by Raisbeck and Yiou (1979), the average 41Ca:40Ca ratio of 2×10-15 (range: 0.6 to 4.2×10-15) that we measure in modern bone is an order of magnitude lower than that obtained previously by Henning, et al (1987) on a cow bone that was measured using AMS following isotope enrichment. The low value and the variability (more than a factor of seven) of the 41Ca:40Ca ratio in modern bone make the possibility of dating bones using 41Ca unlikely.

Estimation of Interlayer Thickness in Inorganic Particulate-Filled Polymer Composites

2011 ◽  
Vol 24 (6) ◽  
pp. 777-788 ◽  
Author(s):  
J.Z. Liang
Keyword(s):  
Polymer Composites ◽  
Volume Fraction ◽  
Particle Diameter ◽  
Interfacial Structure ◽  
Interlayer Thickness ◽  
Filled Polymer ◽  
Mechanical And Physical Properties ◽  
The Relationship ◽  
Good Agreement

The structure of the interlayer between matrix and inclusions affect directly the mechanical and physical properties of inorganic particulate-filled polymer composites. The interlayer thickness is an important parameter for characterization of the interfacial structure. The effects of the interlayer between the filler particles and matrix on the mechanical properties of polymer composites were analyzed in this article. On the basis of a simplified model of interlayer, an expression for estimating the interlayer thickness ([Formula: see text]) was proposed. In addition, the relationship between the [Formula: see text] and the particle size and its concentration was discussed. The results showed that the calculations of the [Formula: see text] and thickness/particle diameter ratio ([Formula: see text]) increased nonlinearly with an increase of the volume fraction of the inclusions. Moreover, the predictions of [Formula: see text] and the relevant data reported in literature were compared, and good agreement was found between them.

TCAD Study of the Raised SiGe Source/Drain in 40nm PMOS

2015 ◽  
Vol 645-646 ◽  
pp. 70-74 ◽  
Author(s):  
Min Zhong ◽  
Yu Hang Zhao ◽  
Shou Mian Chen ◽  
Ming Li ◽  
Shao Hai Zeng ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Critical Role ◽  
Sige Layer ◽  
Strain Engineering ◽  
Effect Transistor ◽  
Simulation Results ◽  
Aided Design ◽  
The Relationship ◽  
Growth Experiments ◽  
Good Agreement

An embedded SiGe layer was applied in the source/drain areas (S/D) of a field-effect transistor to boost the performance in the p channels. Raised SiGe S/D plays a critical role in strain engineering. In this study, the relationship between the SiGe overfilling and the enhancement of channel stress was investigated. Systematic technology computer aided design (TCAD) simulations of the SiGe overfill height in a 40 nm PMOS were performed. The simulation results indicate that a moderate SiGe overfilling induces the highest stress in the channel. Corresponding epitaxial growth experiments were done and the obtained experimental data was in good agreement with the simulation results. The effect of the SiGe overfilling is briefly discussed. The results and conclusions presented within this paper might serve as useful references for the optimization of the embedded SiGe stressor for 40 nm logic technology node and beyond.

scholarly journals Excessive Pressure in Multichambered Cuffs Used for Sequential Compression Therapy

2002 ◽  
Vol 82 (10) ◽  
pp. 1000-1008 ◽  
Author(s):  
Patrick Segers ◽  
Jean-Paul Belgrado ◽  
Andre Leduc ◽  
Olivier Leduc ◽  
Pascal Verdonck
Keyword(s):  
Time Course ◽  
Compression Therapy ◽  
Lymphatic Drainage ◽  
Chamber Pressure ◽  
Excessive Pressure ◽  
Ellipsoidal Model ◽  
Order Of Magnitude ◽  
Pneumatic Compression Devices ◽  
Target Pressure ◽  
The Relationship

Abstract Background and Purpose. Pneumatic compression devices, used as part of the therapeutic strategy for lymphatic drainage, often have cuffs with multiple chambers that are inflated sequentially. The purpose of this study was to investigate (1) the relationship between cuff chamber pressure (Pchamber) and the pressure on the cuff-skin interface (Pinterface) and (2) the mechanical interaction of cuff chambers and consequences for device control. Subjects and Methods. In this study, we used 3 cylindrical (60-, 80-, and 100-mm-diameter) model limbs and 1 ellipsoidal model of the arm to test a commercially available pressure controller using “target pressures,” indicated by the controller, of 30, 60, 80, and 100 mm Hg. We studied the time course of Pchamber and Pinterface during the inflation sequence and the effect of local curvature on Pinterface. Results. Our data indicated that, overall, Pinterface is of the same order of magnitude as Pchamber. There was some effect of model diameter and shape, with the smaller curvatures yielding the highest Pinterface. Cuff chamber interaction led to Pchamber and Pinterface values in the most distal (first inflated) chamber that were up to 80% higher than the target pressure. For the 80-mm cylindrical model, for instance, pressure in this chamber reached 54, 98, 121, and 141 mm Hg, respectively, instead of the 30, 60, 80, and 100 mm Hg indicated by the controller. Discussion and Conclusion. The discrepancy between the target pressure, indicated by the controller, and the pressure measured inside the cuff chambers undermines the therapeutic control and efficacy of the pneumatic compression devices. Because the measured pressures were far beyond the pressure level indicated by the controller, it is recommended that pneumatic compression devices be used at much lower target pressures (<30 mm Hg) than those applied in clinical practice.

Optical Vibration and Acceleration Sensor With a Silicon Cantilever

1999 ◽  
Author(s):  
Mitsuteru Kimura ◽  
Katsuhisa Toshima ◽  
Harunobu Satoh
Keyword(s):  
Simple Model ◽  
Optical Fiber ◽  
Resonance Frequency ◽  
Acceleration Sensor ◽  
Frequency Range ◽  
Silicon Cantilever ◽  
All Optical ◽  
New Type ◽  
Good Agreement ◽  
Optical Vibration

Abstract A new type all optical vibration and acceleration sensor using the combination of micromachined Si cantilever and optical fiber is proposed, and its fundamental characteristics are demonstrated. The light emitted from bulb-lens set into the V-groove is reflected at the reflector formed on the Si cantilever and then recoupled into the bulb-lens. Several sensors with different length (0.64–6.0 mm long) of the Si cantilever are fabricated to compare the theoretical resonance frequency fr obtained from the simple model and experimental ones. They had good agreement. From the sensing principle the sensing frequency range of the vibration is suitable below the fr of the Si cantilever of the sensor.

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