scholarly journals The algebra and geometry of curve and surface inversion

Author(s):  
T.W. Sederberg ◽  
Eng-Wee Chionh
Keyword(s):  
Author(s):  
Balakrishnam Jampana ◽  
Andrew Melton ◽  
Muhammad Jamil ◽  
Ian Ferguson ◽  
Robert Opila ◽  
...  

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 610
Author(s):  
Yu Shi ◽  
Lei Liu ◽  
Fei Hu ◽  
Guangqiang Fan ◽  
Juntao Huo

To investigate the evolution of the nocturnal boundary layer (NBL) and its impacts on the vertical distributions of pollutant particulates, a combination of in situ observations from a large tethered balloon, remote sensing instruments (aerosol lidar and Doppler wind lidar) and an atmospheric environment-monitoring vehicle were utilized. The observation site was approximately 100 km southwest of Beijing, the capital of China. Results show that a considerable proportion of pollutant particulates were still suspended in the residual layer (RL) (e.g., the nitrate concentration reached 30 μg m−3) after sunset. The NBL height calculated by the aerosol lidar was closer to the top of the RL before midnight because of the pollutants stored aloft in the RL and the shallow surface inversion layer; after midnight, the NBL height was more consistent with the top of the surface inversion layer. As the convective mixing layer gradually became established after sunrise the following day, the pollutants stored in the nocturnal RL of the preceding night were entrained downward into the mixing layer. The early morning PM2.5 concentration near 700 m in the RL on 20 December decreased by 83% compared with the concentration at 13:34 on 20 December at the same height. The nitrate concentration also decreased significantly in the RL, and the mixing down of nitrate from the RL could contribute about 37% to the nitrate in the mixing layer. Turbulence activities still existed in the RL with the bulk Richardson number (Rb) below the threshold value. The corresponding increase in PM2.5 was likely to be correlated with the weak turbulence in the RL in the early morning.


Author(s):  
Balakrishnam Jampana ◽  
Andrew Melton ◽  
Muhammad Jamil ◽  
Ian Ferguson ◽  
Robert Opila ◽  
...  

Author(s):  
Kit Man Cham ◽  
Soo-Young Oh ◽  
Daeje Chin ◽  
John L. Moll

2003 ◽  
Vol 251 (1-4) ◽  
pp. 337-341 ◽  
Author(s):  
Kanji Yoh ◽  
Hiroshi Ohno ◽  
Yoshito Katano ◽  
Koichi Mukasa ◽  
Manfred Ramsteiner

2003 ◽  
Vol 763 ◽  
Author(s):  
Dongxiang Liao ◽  
Angus Rockett

AbstractThe surface chemical composition of Cu(In, Ga)Se2 (CIGS) alloys and CIGS/CdS interfaces are characterized by photoelectron emission spectroscopy. The results show that there is a severe but shallow (1-2 atomic layers) Cu depletion at {112} surfaces of CuInSe2 epitaxial films, consistent with earlier results. The depletion is not due to the existence of ordered defect compounds, but likely a result of the reconstruction of polar CIGS surfaces. Cd was found incorporated into the top 1-2 atomic layers of Cu-poor surfaces of CIGS, which may explain the n-type surface inversion in finished devices. These results and others formed the basis of a numerical model of CIGS solar cells. It is argued from the experimental and simulation results that the performance of devices based on high Ga content alloys may be reduced by failure to dope the surface of CuGaSe2 sufficiently n-type. The effect of observed defect states on the energy gap is considered, in particular with respect to pinning of the Fermi level near the heterojunction. By contrast, devices based on high In-content alloys show strong surface inversion in CIGS/CdS heterojunctions, which is suggestive of an effect of Cd incorporation in the CIGS surface.


2019 ◽  
Vol 115 (23) ◽  
pp. 231602
Author(s):  
David A. J. Millar ◽  
Uthayasankaran Peralagu ◽  
Xu Li ◽  
Matthew J. Steer ◽  
Yen-Chun Fu ◽  
...  

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