Results 291 to 300 of about 9,836,724 (331)

Phase behavior of gradient copolymers

AIP Conference Proceedings, 2000
Phase properties of gradient AB copolymer melts which consist of chains with the specified chemical distribution of A and B monomers have been studied within the Landau-Ginzburg model. All the melts with the linear distribution of the monomers exhibit only a direct continuous phase transition from disordered to the lamellar phase.
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Mechanism Behind Angularly Asymmetric Diffraction in Phase-Gradient Metasurfaces

Physical Review Applied, 2019
Phase-gradient metasurfaces (PGMs) provide remarkable control over the propagation of light. One expects that the number of unit cells $m$ in a supercell should not change the nature of a PGM's diffraction characteristics, yet recent experiments have ...
Yanyan Cao, Yangyang Fu, Qingjia Zhou, X. Ou, Lei Gao, Huanyang Chen, Yadong Xu   +6 more
semanticscholar   +1 more source

The twisted solenoid RF phase gradient transmit coil for TRASE imaging.

Journal of magnetic resonance (San Diego, Calif. 1997 : Print), 2019
TRASE is an MRI k-space encoding method that uses radio-frequency (RF or B1) transmit phase gradient fields to achieve millimeter-level spatial resolution.
Hongwei Sun, Stephanie Yong, J. Sharp
semanticscholar   +1 more source

Design and Implementation of a Dual Frequency and Bidirectional Phase Gradient Metasurface for Beam Convergence

IEEE Antennas and Wireless Propagation Letters, 2019
A phase gradient metasurface (PGM) array with beam converge characteristic in reflection direction at 15 GHz and transmission direction at 5.6 GHz is proposed in this letter.
Haojie Yue, Lei Chen, Yaozhou Yang, Lianxing He, Xiao-wei Shi   +4 more
semanticscholar   +1 more source

Monolithic stationary phases with a longitudinal gradient of porosity

Journal of Separation Science, 2017
The duration of the hypercrosslinking reaction has been used to control the extent of small pores formation in polymer‐based monolithic stationary phases. Segments of five columns hypercrosslinked for 30–360 min were coupled via zero‐volume unions to prepare columns with segmented porosity gradients.
Jiří, Urban, Tomáš, Hájek, Frantisek, Svec   +2 more
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A Phase Calibration Method Based on Phase Gradient Autofocus for Airborne Holographic SAR Imaging

IEEE Geoscience and Remote Sensing Letters, 2019
Holographic synthetic aperture radar tomography can realize full 3-D reconstructions of objects over 360° with very high resolution, and thus becomes an interesting 3-D imaging technique.
Dong Feng, D. An, Xiaotao Huang, Yueli Li   +3 more
semanticscholar   +1 more source

Backpropagation with two-phase magnified gradient function

2008 IEEE International Joint Conference on Neural Networks (IEEE World Congress on Computational Intelligence), 2008
Backpropagation (BP) learning algorithm is the most widely supervised learning technique which is extensively applied in the training of multi-layer feed-forward neural networks. Many modifications have been proposed to improve the performance of BP, and BP with Magnified Gradient Function (MGFPROP) is one of the fast learning algorithms which improve ...
Chi-Chung Cheung, Sin Chun Ng
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Wideband RCS Reduction of a Slot Array Antenna Using Phase Gradient Metasurface

IEEE Antennas and Wireless Propagation Letters, 2018
In this letter, a slot array antenna loaded with a phase gradient metasurface (PGM) for a monostatic radar cross-section (RCS) reduction is presented.
Wenbo Zhang, Y. Liu, S. Gong, Jun Wang, Yuezhi Jiang   +4 more
semanticscholar   +1 more source

Phase Transition as a Gradient Amplifier

Science's STKE, 2005
Chemotactic cells can detect and move toward a shallow gradient of chemoattractant. This directional movement involves the localized synthesis of membrane lipids, specifically phosphatidylinositol 3,4,5-trisphosphate (PIP 3 ), which is formed in response to recruitment of phosphoinositide 3-kinase (PI3K) at the site
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Phase Retrieval via Accelerated Gradient Descent

2019
Phase retrieval, as a non-convex optimization problem arises in many areas of signal processing, is to recover the missed signal phase. Based on the Truncated Wirtinger Flow (TWF), where the updating can be regarded as stochastic gradient descent, we present the Accelerated Wirtinger Flow (AWF), which updates the iterative process with accelerated ...
openaire   +1 more source