Testing of Concave Aspheric Surface with Self-Collimating and Correcting Lens in Front of Back Conjugate Point

2020 ◽  
Vol 40 (20) ◽  
pp. 2022002
Author(s):  
赵鹏玮 Zhao Pengwei ◽  
戚丽丽 Qi Lili ◽  
张金平 Zhang Jinping ◽  
郑列华 Zheng Liehua
Keyword(s):  
Conjugate Point ◽  
Aspheric Surface

scholarly journals Equatorial spreadFinitiation and growth from satellite traces as revealed from conjugate point observations in Brazil

2014 ◽  
Vol 119 (1) ◽  
pp. 375-383 ◽  
Author(s):  
M. A. Abdu ◽  
E. A. Kherani ◽  
I. S. Batista ◽  
B. W. Reinisch ◽  
J. H. A. Sobral
Keyword(s):  
Conjugate Point

Higher order Wirtinger inequalities

1980 ◽  
Vol 85 (1-2) ◽  
pp. 87-110 ◽  
Author(s):  
Kurt Kreith ◽  
Charles A. Swanson
Keyword(s):  
Boundary Conditions ◽  
Quadratic Forms ◽  
Differential Operators ◽  
Conjugate Point ◽  
Wirtinger Inequality ◽  
Even Order ◽  
Linear Differential ◽  
Natural Boundary Conditions ◽  
Derivatives Of ◽  
Admissible Functions

SynopsisWirtinger-type inequalities of order n are inequalities between quadratic forms involving derivatives of order k ≦ n of admissible functions in an interval (a, b). Several methods for establishing these inequalities are investigated, leading to improvements of classical results as well as systematic generation of new ones. A Wirtinger inequality for Hamiltonian systems is obtained in which standard regularity hypotheses are weakened and singular intervals are permitted, and this is employed to generalize standard inequalities for linear differential operators of even order. In particular second order inequalities of Beesack's type are developed, in which the admissible functions satisfy only the null boundary conditions at the endpoints of [a, b] and b does not exceed the first systems conjugate point (a) of a. Another approach is presented involving the standard minimization theory of quadratic forms and the theory of “natural boundary conditions”. Finally, inequalities of order n + k are described in terms of (n, n)-disconjugacy of associated 2nth order differential operators.

Computer numeric control subaperture aspheric surface polishing—microroughness evaluation

2014 ◽  
Vol 53 (9) ◽  
pp. 092011 ◽  
Author(s):  
Frantisek Prochaska ◽  
Jaroslav Polak ◽  
Ondrej Matousek ◽  
David Tomka
Keyword(s):  
Aspheric Surface ◽  
Surface Polishing ◽  
Computer Numeric Control

THE INVESTIGATION OF THE PG PULSATIONS WITH USING DATA OF ARASE, GOES SATELLITES AND GROUND-BASED STATIONS

2021 ◽  
Vol 44 ◽  
pp. 63-66
Author(s):  
V.B. Belakhovsky ◽  
◽  
V.A. Pilipenko ◽  
K. Shiokawa ◽  
Y. Miyoshi ◽  
...  
Keyword(s):  
Geomagnetic Field ◽  
Conjugate Point ◽  
Physical Nature ◽  
Recovery Phase ◽  
Radial Component ◽  
Field Lines ◽  
Using Data ◽  
Giant Pulsations ◽  
Favorable Conditions ◽  
Phase Relationships

The physical nature of Pg (pulsation giant) pulsations, which were observed in the magnetosphere by the Japanese satellite Arase, geostationary satellites GOES, and ground stations of the THEMIS and CARISMA networks, was investigated in this work. Pg pulsations belong to the Pc4 frequency range and are characterized by a very monochromatic shape. For the event on 5 June, 2018, according to the data from the Arase satellite, the Pg pulsation wave packet was recorded in the dawn sector during 3 hours. The pulsations are most pronounced in the radial component of the geomagnetic field, their frequency was about 11 mHz. Pg pulsations observed in the magnetosphere were accompanied by pulsations with the same period according to data from a number of ground-based magnetic stations located near the conjugate point. According to the data of ground stations, the pulsations were most strongly expressed in the Y-component of the geomagnetic field. Pg pulsations were accompanied by pulsations in electron and proton fluxes according to the Arase, GOES satellite observations. There are no clear phase relationships between geomagnetic pulsations and pulsations in charge particle fluxes. Pg pulsations were excited under quiet geomagnetic conditions (SYM-H = -10 nT, AE = 100-400 nT) on the recovery phase of the small geomagnetic storm. It is assumed that the expansion of the plasmasphere at low geomagnetic activity leads to an increase in the plasma density in the region of the geostationary orbit, which creates favorable conditions for the excitation of Pg pulsations due to the drift-bounce resonance of protons with the geomagnetic field lines oscillations in the magnetosphere.

Improving as-built miniature lenses that use many aspheric surface coefficients with two desensitizing techniques

2021 ◽  
Vol 60 (05) ◽  
Author(s):  
Leticia Carrión-Higueras ◽  
Arnau Calatayud ◽  
José Sasian
Keyword(s):  
Aspheric Surface

All-sky-imaging capabilities for ionospheric space weather research using geomagnetic conjugate point observing sites

2018 ◽  
Vol 61 (7) ◽  
pp. 1636-1651 ◽  
Author(s):  
C. Martinis ◽  
J. Baumgardner ◽  
J. Wroten ◽  
M. Mendillo
Keyword(s):  
Space Weather ◽  
Conjugate Point ◽  
Weather Research

The position shifting of frequency spectrum of Fourier transform in the application of aspheric surface testing

2007 ◽  
Author(s):  
Junmiao Weng ◽  
Yongying Yang ◽  
Dong Liu ◽  
Yibing Shen ◽  
Yongmo Zhuo
Keyword(s):  
Fourier Transform ◽  
Frequency Spectrum ◽  
Aspheric Surface ◽  
Surface Testing

scholarly journals Latitudinal and Local Time Variation of Ionospheric Turbulence Parameters during the Conjugate Point Equatorial Experiment in Brazil

2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Charles S. Carrano ◽  
Cesar E. Valladares ◽  
Keith M. Groves
Keyword(s):  
Spectral Index ◽  
Local Time ◽  
Conjugate Point ◽  
Local Times ◽  
Turbulent Intensity ◽  
Scintillation Index ◽  
Equatorial Anomaly ◽  
Noise Measurements ◽  
Gps Scintillations ◽  
Turbulence Parameters

Previous authors have reported on the morphology of GPS scintillations and irregularity zonal drift during the 2002 Conjugate Point Equatorial Experiment (COPEX) in Brazil. In this paper, we characterize the turbulent ionospheric medium that produced these scintillations. Using 10 Hz GPS carrier-to-noise measurements at Boa Vista (2.9°N, 60.7°W), Alta Floresta (9.9°S, 56.1°W), and Campo Grande (20.5°S, 54.7°W), we report on the variation of turbulent intensity, phase spectral index, and irregularity zonal drift as a function of latitude and local time for the evening of 1-2 November 2002. The method of analysis is new and, unlike analytical theories of scintillation based on the Born or Rytov approximations, it is valid when the scintillation index saturates due to multiple-scatter effects. Our principal findings are that (1) the strength of turbulence tended to be largest near the crests of the equatorial anomaly and at early postsunset local times, (2) the turbulent intensity was generally stronger and lasted two hours longer at Campo Grande than at Boa Vista, (3) the phase spectral index was similar at the three stations but increased from 2.5 to 4.5 with local time, and (4) our estimates of zonal irregularity drift are consistent with those provided by the spaced-receiver technique.

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