Wyniki wyszukiwania - Biblioteka Nauki

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Statistical analysis of backscattered laser signals from rough targets in the laser altimeter application

100%

Guo G. , Qu S. , Jiao W. , Chen X.

Optica Applicata

2009

tom Vol. 39, nr 3

511-519

Statistical properties of the scattered field for a laser altimeter are considered. Analytical expressions are developed for the optical field correlation function and intensity correlation function, as well as the correlation degree of intensities of speckle patterns. The relationship between the backscattered signal intensity and the target roughness is analyzed.

Effects of gibberellins A4 on budbreak, antioxidant enzymes’ activity and proline content of flower buds in sweet cherry (Prunus avium)

75%

Cai B. , Wang H. , Liu T. , Zhuang W. , Wang Z. , Qu S. , Qin Y.

Acta Physiologiae Plantarum

2019

tom 41

nr 06

Chilling accumulation is required for deciduous trees to maintain its normal growth and development. However, warm winters appeared more and more frequently, which hindered severely the normal growth and yield of fruit trees. To avoid these problems, artificial dormancy breaking agents are widely used. In our study, the effect of mineral oil, hydrogen cyanamide and gibberellins A₄ (GA₄) on budbreak were evaluated in sweet cherry (Prunus avium), which indicated that GA₄ treatment hastened the date of flower budbreak and increased the percentage of budbreak compared with the other treatments. To better understand the mechanism of GA₄-induced budbreak, the contents of antioxidant enzymes’ activity and proline in sweet cherry flower buds treated with GA₄ and water were evaluated. There was a sharp decrease of catalase (CAT) activity after 5 days of GA₄ treatment and then an increase of CAT activity after 10 days of GA₄ treatment. However, there was a sharp increase of superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) after 5 days of GA₄ treatment and then a decrease of these enzyme activities after 10 days of GA₄ treatment. There was a transient increase in hydrogen peroxide (H₂O₂) content and proline content after 5 days of GA₄ treatment and a decrease after 10 days of GA₄ treatment. However, there were only small fluctuations after water treatment, which indicated that temporary oxidative stress may contribute to the dormancy release of flower buds in the sweet cherry treated with GA₄ through the regulation of H₂O₂ content coincided with the changes of antioxidant defense system.

Deblending of Simultaneous-source Seismic Data using Fast Iterative Shrinkage-thresholding Algorithm with Firm-thresholding

63%

Qu S. , Zhou H. , Liu R. , Chen Y. , Zu S. , Yu S. , Yuan J. , Yang Y.

Acta Geophysica

2016

tom Vol. 64, no. 4

1064--1092

In this paper, an improved algorithm is proposed to separate blended seismic data. We formulate the deblending problem as a regularization problem in both common receiver domain and frequency domain. It is suitable for different kinds of coding methods such as random time delay discussed in this paper. Two basic approximation frames, which are iterative shrinkage-thresholding algorithm (ISTA) and fast iterative shrinkage-thresholding algorithm (FISTA), are compared. We also derive the Lipschitz constant used in approximation frames. In order to achieve a faster convergence and higher accuracy, we propose to use firm-thresholding function as the thresholding function in ISTA and FISTA. Two synthetic blended examples demonstrate that the performances of four kinds of algorithms (ISTA with soft- and firm-thresholding, FISTA with soft- and firm-thresholding) are all effective, and furthermore FISTA with a firm-thresholding operator exhibits the most robust behavior. Finally, we show one numerically blended field data example processed by FISTA with firm-thresholding function.