scholarly journals Concentration of Solar Energy Using Optical Systems Designed from a Set of Conical Rings

Solar Power ◽  
10.5772/28360 ◽  
2012 ◽  
Author(s):  
Jorge Gonzlez-Garca ◽  
Sergio Vzquez-Montiel ◽  
Agustin Santiago-Alvarado ◽  
Graciela Castro-Gonzlez
Keyword(s):  

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.



Author(s):  
J T Fourie

The attempts at improvement of electron optical systems to date, have largely been directed towards the design aspect of magnetic lenses and towards the establishment of ideal lens combinations. In the present work the emphasis has been placed on the utilization of a unique three-dimensional crystal objective aperture within a standard electron optical system with the aim to reduce the spherical aberration without introducing diffraction effects. A brief summary of this work together with a description of results obtained recently, will be given.The concept of utilizing a crystal as aperture in an electron optical system was introduced by Fourie who employed a {111} crystal foil as a collector aperture, by mounting the sample directly on top of the foil and in intimate contact with the foil. In the present work the sample was mounted on the bottom of the foil so that the crystal would function as an objective or probe forming aperture. The transmission function of such a crystal aperture depends on the thickness, t, and the orientation of the foil. The expression for calculating the transmission function was derived by Hashimoto, Howie and Whelan on the basis of the electron equivalent of the Borrmann anomalous absorption effect in crystals. In Fig. 1 the functions for a g220 diffraction vector and t = 0.53 and 1.0 μm are shown. Here n= Θ‒ΘB, where Θ is the angle between the incident ray and the (hkl) planes, and ΘB is the Bragg angle.





1882 ◽  
Vol 13 (333supp) ◽  
pp. 5317-5317
Author(s):  
W. B. Carpenter
Keyword(s):  




1999 ◽  
Vol 09 (PR3) ◽  
pp. Pr3-41-Pr3-46
Author(s):  
C. Royère
Keyword(s):  


1988 ◽  
Vol 49 (C2) ◽  
pp. C2-343-C2-348
Author(s):  
L. A. LUGIATO ◽  
C. OLDANO ◽  
Kaige WANG ◽  
L. SANTIRANA ◽  
L. M. NARDUCCI ◽  
...  
Keyword(s):  


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