scholarly journals Origins of the odd optical observables in plutonium and americium tungstates

2019 ◽  
Vol 10 (26) ◽  
pp. 6508-6518 ◽  
Author(s):  
Justin N. Cross ◽  
Tsung-Han Lee ◽  
Chang-Jong Kang ◽  
Yong-Xin Yao ◽  
Samantha K. Cary ◽  
...  
Keyword(s):  
Optical Properties ◽  
The Other ◽  
Normal Absorption ◽  
5F Electrons ◽  
Absorption Features

A series of f-block tungstates show atypical coloration for both the Ce(iii) and Pu(iii) compounds; whereas the other lanthanide and Am(iii) compounds possess normal absorption features. The different optical properties are actually derived from the tungstate component rather than from 5f electrons/orbitals.

Practical Correction of Three Fold Astigmatism in the Philips CM TEM

1996 ◽  
Vol 54 ◽  
pp. 418-419
Author(s):  
Arno J. Bleeker ◽  
Mark H.F. Overwijk ◽  
Max T. Otten
Keyword(s):  
Optical Properties ◽  
Phase Contrast ◽  
The Other ◽  
Objective Lens ◽  
Symmetric Part ◽  
A Posteriori ◽  
Contrast Transfer Function ◽  
High Brightness ◽  
Rotationally Symmetric ◽  
Brightness Field

With the improvement of the optical properties of the modern TEM objective lenses the point resolution is pushed beyond 0.2 nm. The objective lens of the CM300 UltraTwin combines a Cs of 0. 65 mm with a Cc of 1.4 mm. At 300 kV this results in a point resolution of 0.17 nm. Together with a high-brightness field-emission gun with an energy spread of 0.8 eV the information limit is pushed down to 0.1 nm. The rotationally symmetric part of the phase contrast transfer function (pctf), whose first zero at Scherzer focus determines the point resolution, is mainly determined by the Cs and defocus. Apart from the rotationally symmetric part there is also the non-rotationally symmetric part of the pctf. Here the main contributors are not only two-fold astigmatism and beam tilt but also three-fold astigmatism. The two-fold astigmatism together with the beam tilt can be corrected in a straight-forward way using the coma-free alignment and the objective stigmator. However, this only works well when the coefficient of three-fold astigmatism is negligible compared to the other aberration coefficients. Unfortunately this is not generally the case with the modern high-resolution objective lenses. Measurements done at a CM300 SuperTwin FEG showed a three fold-astigmatism of 1100 nm which is consistent with measurements done by others. A three-fold astigmatism of 1000 nm already sinificantly influences the image at a spatial frequency corresponding to 0.2 nm which is even above the point resolution of the objective lens. In principle it is possible to correct for the three-fold astigmatism a posteriori when through-focus series are taken or when off-axis holography is employed. This is, however not possible for single images. The only possibility is then to correct for the three-fold astigmatism in the microscope by the addition of a hexapole corrector near the objective lens.

scholarly journals Influence of Fe2O3 Dopant on Dielectric, Optical Conductivity and Nonlinear Optical Properties of Doped ZnO-Polystyrene Composites Films

2021 ◽  
Vol 12 (1) ◽  
pp. 170-179
Keyword(s):  
Optical Properties ◽  
Optical Conductivity ◽  
Electron Mobility ◽  
Relative Permittivity ◽  
Nonlinear Optical ◽  
The Other ◽  
Filler Concentration ◽  
Casting Method ◽  
Polystyrene Nanoparticles ◽  
Doped Zno

ZnO-Polystyrene nanoparticles doped with Fe2O3 were prepared by the casting method. Both Ed and Eo were calculated. εL and N/m* increase with filler concentrations for these samples. On the other hand, both M-1, M-3, decreased with increasing filler. The filler concentrations affected on determined values of both of ε\ and ε\\. These values increase with filler, and also the same result was achieved for both σ1 and σ2, which also increases with filler. The relation between VELF and SELF was determined. χ(1) increases with increasing filler ratio. n2, χ(3), βc, were determined theoretically. The electrical susceptibility χe and relative permittivity εr increase with the increase of filler concentration as a result of increasing electron mobility.

Physical a priori solar radiation pressure models for GNSS satellites with the focus on BDS

2021 ◽  
Author(s):  
Bingbing Duan ◽  
Urs Hugentobler ◽  
Inga Selmke ◽  
Stefan Marz
Keyword(s):  
Optical Properties ◽  
Solar Radiation ◽  
Thermal Radiation ◽  
Radiation Pressure ◽  
Total Mass ◽  
A Priori ◽  
Solar Radiation Pressure ◽  
The Other ◽  
Time Range ◽  
Satellite Attitude

<p>A physical a priori box-wing solar radiation pressure (SRP) model is widely used by most analysis centers for Galileo and QZSS (Quasi-Zenith Satellite System) satellites, complemented by an ECOM or ECOM2 (Empirical CODE Orbit Model) model. For the other constellations, for instance GPS and GLONASS satellites, optical properties of satellite surfaces are not publicly available, especially for GPS Block IIF and GLONASS satellites. By fixing satellite surface areas and total mass to the values from some unpublished documents, we estimate satellite surface optical properties based on true GNSS measurements covering long time periods (typically this should be longer than a full beta angle time range to reduce correlations between parameters). Meanwhile, various physical effects are considered, such as yaw bias, radiator emission and thermal radiation of solar panels. We find that yaw bias of GPS Block IIA and IIR satellites does not dominate the Y-bias, it is likely that heat generated in the satellite is radiated from louvers or heat pipes on the Y side of the satellite. It is also noted that the ECOM Y0 estimates of both GPS and GLONASS satellites show clear anomaly during eclipse seasons. This indicates that the radiator emission is present when the satellite crosses shadows. Since satellite attitude during eclipse seasons could be different from the nominal yaw, potential radiator effect in the –X surface could be wrongly absorbed by the ECOM Y0 as well. By considering all the estimated parameters in an a priori model we observe clear improvement in satellite orbits, especially for GLONASS satellites. China’s Beidou-3 satellites are now providing PNT (positioning, navigation and timing) service globally. Satellite attitude, dimensions and total mass are publicly available. Also, the absorption optical properties of each satellite surface are given. With all this information, we estimate the other optical properties of Beidou satellites considering similar yaw bias, radiator and thermal radiation effects as those in GPS and GLONASS satellites.</p>

A New General Method for the Determination of Optical Properties of Amorphous Silicon Films

1990 ◽  
Vol 192 ◽  
Author(s):  
G. Amato ◽  
L. Boarino ◽  
F. Fizzotti ◽  
C. Manfredotti
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Amorphous Silicon ◽  
Optical Response ◽  
The Other ◽  
New Method ◽  
Silicon Thin Films ◽  
Physical Insight ◽  
General Method

ABSTRACTWe propose to apply a new method to model the optical response of amorphous silicon thin films. This method presents the advantage of having a good physical insight. On the other hand, although the model has been originally tested on different materials like a-Si, a-Ge and a-GaAs, we show that it is also sensitive to small differences like those that can exist between intrinsic and doped a-Si:H.

A re-examination of siphonophore terminology and morphology, applied to the description of two new prayine species with remarkable bio-optical properties

2005 ◽  
Vol 85 (3) ◽  
pp. 695-707 ◽  
Author(s):  
Steven H.D. Haddock ◽  
Casey W. Dunn ◽  
Philip R. Pugh
Keyword(s):  
Optical Properties ◽  
White Light ◽  
Diagnostic Value ◽  
The Other ◽  
Light Illumination ◽  
Structural Coloration ◽  
Dramatic Form ◽  
White Light Illumination

Siphonophores (Cnidaria: Hydrozoa) are dominant members of the carnivorous plankton, and they are known for their ability to produce bioluminescence. Here we describe two new calycophoran species (sub-family Prayinae) that are unique in their morphological and optical traits. One species, Gymnopraia lapislazula gen. nov., sp. nov., displays a dramatic form of blue structural coloration, and the other, Lilyopsis fluoracantha, sp. nov., bears an exceptional amount of fluorescence–enough to give a greenish cast during white-light illumination. We also introduce a consistent terminology for siphonophore axes and zooids, discuss characters important for distinguishing the known prayine genera, and suggest that the presence or absence of a disjunct pedicular canal could be of diagnostic value for the group.

scholarly journals Similarities and differences of aerosol optical properties between southern and northern sides of the Himalayas

2014 ◽  
Vol 14 (6) ◽  
pp. 3133-3149 ◽  
Author(s):  
C. Xu ◽  
Y. M. Ma ◽  
A. Panday ◽  
Z. Y. Cong ◽  
K. Yang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Monsoon Season ◽  
Diurnal Variations ◽  
The Other ◽  
The Tibetan Plateau ◽  
Aerosol Optical Properties ◽  
Coarse Mode ◽  
Southern Side ◽  
Northern Side ◽  
The Himalaya

Abstract. The Himalaya mountains along the southern edge of the Tibetan Plateau act as a natural barrier for the transport of atmospheric aerosols from the polluted regions of South Asia to the main body of the Tibetan Plateau. In this study, we investigate the seasonal and diurnal variations of aerosol optical properties measured at two Aerosol Robotic Network (AERONET) sites on the southern side of the Himalaya (Pokhara, 812 m above sea level (a.s.l.) and EVK2-CNR, 5079 m a.s.l. in Nepal) and one on the northern side (Qomolangma (Mt. Everest) station for Atmospheric and Environmental Observation and Research, Chinese Academy of Sciences (QOMS_CAS) in Tibet, 4076 m a.s.l. in China). While observations at QOMS_CAS and EVK2-CNR can generally be representative of a remote background atmosphere, Pokhara is a lower-elevation suburban site with much higher aerosol load due to both the influence of local anthropogenic activities and to its proximity to the Indo-Gangetic Plains. The annual mean aerosol optical depth (AOD) during the investigated period was 0.05 at QOMS_CAS, 0.04 at EVK2-CNR and 0.51 at Pokhara, respectively. Seasonal variations of aerosols are profoundly affected by large-scale atmospheric circulation. Vegetation fires, peaking during April in the Himalayan region and northern India, contribute to a growing fine mode AOD at the three stations. Dust transported to these sites, wind erosion and hydrated/cloud-processed aerosols lead to an increase in coarse mode AOD during the monsoon season at QOMS_CAS and EVK2-CNR. Meanwhile, coarse mode AOD at EVK2-CNR is higher than at QOMS_CAS in August and September, indicating that the transport of coarse mode aerosols from the southern to the northern side may be effectively reduced. The effect of precipitation scavenging is clearly seen at Pokhara, which sees significantly reduced aerosol loads during the monsoon season. Unlike the seasonal variations, diurnal variations are mainly influenced by meso-scale systems and local topography. The diurnal pattern in precipitation appears to contribute to diurnal changes in AOD through the effect of precipitation scavenging. AOD exhibits diurnal patterns related to emissions in Pokhara, while it does not at the other two high-altitude sites. At EVK2-CNR, the daytime airflow carries aerosols up from lower-altitude polluted regions, leading to increasing AOD, while the other two stations are less influenced by valley winds. Surface heating influences the local convection, which further controls the vertical aerosol exchange and the diffusion rate of pollution to the surrounding areas. Fine and coarse mode particles are mixed together on the southern side of the Himalaya in spring, which may lead to the greater inter-annual difference in diurnal cycles of Ångström exponent (AE) at EVK2-CNR than that at QOMS_CAS.

Optical Properties of a-C:H Films Deposited by Plasma Microwave Discharge with Controlling Substrate Temperature

2011 ◽  
Vol 227 ◽  
pp. 200-203
Author(s):  
M. Kihel ◽  
Salah Sahli ◽  
R. Clergereaux ◽  
P. Raynaud ◽  
Y. Segui
Keyword(s):  
Optical Properties ◽  
Substrate Temperature ◽  
Optical Band Gap ◽  
Microwave Discharge ◽  
Plasma Reactor ◽  
Deposition Process ◽  
The Other ◽  
Amorphous Hydrogenated Carbon ◽  
Deposited Films ◽  
Plasma Microwave

Amorphous hydrogenated carbon (a-C:H) films have been deposited in Microwave Multipolar plasma reactor (MMP) using pure acetylene as precursor with controlling substrate temperature. Investigations on the optical properties of deposited films according to the substrate temperature have been reported. It has been observed that the optical band gap decreases and the Csp2 concentration increases when cooling down the substrate temperature. On the other hand, it has been revealed elsewhere that cooling down the substrate temperature during the deposition process, leads to the increase of particles trapped density in the deposited films due to a phenomenon of thermophoresis. Therefore, the optical properties evolution is linked to the increases of particles trapped density in the deposited films.

Semiconductive Properties of Alternating Mg/C Multi-layer Films with Hydroxylation Treatment

2012 ◽  
Vol 1494 ◽  
pp. 197-202
Author(s):  
Masafumi Chiba ◽  
Daisuke Endo ◽  
Kenichi Haruta ◽  
Hideki Kimura ◽  
Hideo Kiyota
Keyword(s):  
Electrical Conductivity ◽  
Optical Properties ◽  
Water Vapor ◽  
The Other ◽  
Film Sample ◽  
Atmospheric Water ◽  
Initial Formation ◽  
Number Of Layers ◽  
Conductive Film ◽  
Subsequent Exposure

ABSTRACTA Mg(OH)2–C transparent conductive film was prepared using the sputtering method by the initial formation of a Mg-C film generated by the alternate layering of Mg and C on a rotating substrate and subsequent exposure of the film to atmospheric water vapor. To examine the influence exerted by the Mg/C layers of the starting film sample on semiconductivity,evaluations of the electrical conductivity properties of the film during the hydroxylation process and the optical properties after the hydroxylation process were carried out. As a result, although no effects on the characteristics of the electrical conductivity properties associated with the composition or number of layers in the films could be confirmed, it was determined that the films possessed the characteristics of semiconductors. On the other hand, the optical properties were found to be affected by the composition and number of layers of the Mg/C films.

Concluding remarks

1964 ◽  
Vol 282 (1388) ◽  
pp. 147-154 ◽  
Keyword(s):  
Mechanical Properties ◽  
Optical Properties ◽  
Solid State ◽  
Yield Point ◽  
Physical Meaning ◽  
The Other ◽  
Common Interest ◽  
Electrical And Optical Properties ◽  
Glass Making ◽  
Practical Limitation

At this hour after we have had two days of this extremely interesting and exciting Discussion Meeting, I do not want to keep you for very long. I will not even attempt to give you a summary─I cannot at this late hour. What I want to do instead is to give some impression of what this Discussion Meeting has meant to me and what general linking principles I have been able to see in it. Every one of you will also want to make his own evaluation. I feel that the value of a meeting like this is very great because it has brought together, both in the papers and in the discussion, people from hitherto almost exclusively separate disciplines. The metallurgists, the ceramic and glass experts, the polymer chemists and solid-state physicists have met and discussed many topics of common interest to them. We who were concerned with organizing this meeting had to be extremely restrictive to keep the scope within practical bounds. We had to exclude, for instance, all papers dealing with the chemistry of preparation of polymers or those on the different techniques of glass making, and there are other properties, fascinating properties like electrical and optical properties, which could have been touched on had there been more time. We had to stick to a very limited field of properties common to all these new or improved substances, namely, the mechanical properties, and even then not of mechanical properties in general, such as elasti­city. It is quite clear from the way the discussion has gone that only the two major mechanical properties have come into the foreground, one being the yield point or beginning of plasticity, and the other the limit of fracture or total breakdown. These are essentially practical considerations because although the first of these, the yield point, may have some physical meaning, the second is really essentially a practical limitation of the material performance. The presence of preformed cracks, for instance, absolutely limits the use of some materials in different condi­tions of stress.

Dependence of stress-optical coefficients on the mechanical and optical properties of polymers

1973 ◽  
Vol 8 (4) ◽  
pp. 267-276 ◽  
Author(s):  
P S Theocaris
Keyword(s):  
Mechanical Properties ◽  
Refractive Index ◽  
Optical Properties ◽  
Internal Structure ◽  
The Other ◽  
Linear Region ◽  
Non Linear ◽  
Linear Viscoelastic ◽  
Linear Viscoelastic Behaviour ◽  
The One

The internal structure of the stress-optical coefficients, as they are related to various direct interferometric methods, has been analysed and the nature of their components studied. It is shown that the stress-optical coefficients are composed of two parts. The one part depends on the variation of the mechanical properties; the other is related to the variation of the refractive index of the polymer. The influence of the mechanical properties is considerable and comparable to the influence of the optical properties. The study of the mechanical and optical contributions to the values of the stress-optical coefficients included not only the linear, but also the non-linear viscoelastic behaviour of the polymers. It is concluded that the corresponding limits of linearity of these coefficients do not coincide. Furthermore, the influence of the mechanical properties on the stress-optical coefficients is increasing relatively to the influence of the optical properties in the non-linear region.

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