Cutoff frequencies of a parabolic-core W-type fibre

1978 ◽  
Vol 14 (20) ◽  
pp. 676 ◽  
Author(s):  
Arun Kumar ◽  
Ram Chandra ◽  
R.A. Sammut ◽  
A.K. Ghatak
Keyword(s):  
Cutoff Frequencies ◽  
Type Fibre

Cutoff frequencies of W-type fibre with polynomial profile core

1981 ◽  
Vol 17 (1) ◽  
pp. 9 ◽  
Author(s):  
A. Yata ◽  
H. Ikuno
Keyword(s):  
Cutoff Frequencies ◽  
Type Fibre

Investigating Recurrent Neural Networks for OCT A-scan Based Tissue Analysis

2014 ◽  
Vol 53 (04) ◽  
pp. 245-249 ◽  
Author(s):  
S. Otte ◽  
L. Wittig ◽  
G. Hüttmann ◽  
C. Kugler ◽  
D. Drömann ◽  
...  
Keyword(s):  
Short Term Memory ◽  
Pulmonary Nodules ◽  
Patient Specific ◽  
Specific Training ◽  
Reference Distribution ◽  
Human Lung Tissue ◽  
Additional Information ◽  
Cutoff Frequencies ◽  
Low Pass ◽  
Lower Cutoff

Summary Objectives: Optical Coherence Tomography (OCT) has been proposed as a high resolution image modality to guide transbronchial biopsies. In this study we address the question, whether individual A-scans obtained in needle direction can contribute to the identification of pulmonary nodules. Methods: OCT A-scans from freshly resected human lung tissue specimen were recorded through a customized needle with an embedded optical fiber. Bidirectional Long Short Term Memory networks (BLSTMs) were trained on randomly distributed training and test sets of the acquired A-scans. Patient specific training and different pre-processing steps were evaluated. Results: Classification rates from 67.5% up to 76% were archived for different training scenarios. Sensitivity and specificity were highest for a patient specific training with 0.87 and 0.85. Low pass filtering decreased the accuracy from 73.2% on a reference distribution to 62.2% for higher cutoff frequencies and to 56% for lower cutoff frequencies. Conclusion: The results indicate that a grey value based classification is feasible and may provide additional information for diagnosis and navigation. Furthermore, the experiments show patient specific signal properties and indicate that the lower and upper parts of the frequency spectrum contribute to the classification.

scholarly journals Investigation of CMOS Varactors for High-GHz-Range Applications

2009 ◽  
Vol 2009 ◽  
pp. 1-4 ◽  
Author(s):  
Ming Li ◽  
Rony E. Amaya ◽  
Robert G. Harrison ◽  
N. Garry Tarr
Keyword(s):  
Transmission Line ◽  
Pulse Compression ◽  
Nonlinear Transmission Line ◽  
Nonlinear Transmission ◽  
Cutoff Frequencies ◽  
Millimeter Wavelengths ◽  
Capacitance Voltage

This paper explores a variety of different CMOS varactor structures for RF and MMICs. A typical 0.18 μm CMOS foundry process was used as the study platform. The varactors' capacitance-voltage characteristics and cutoff frequencies have been examined up to 55 GHz. The primary aim of this work is to design varactors that can improve nonlinear-transmission-line (NLTL) pulse-compression circuits. The results should also be valuable for other applications up to millimeter wavelengths.

scholarly journals Multiple zero group velocity Lamb modes in an anisotropic plate: propagation along different crystallographic axes

2019 ◽  
Vol 97 (10) ◽  
pp. 1064-1074
Author(s):  
Soufien Karous ◽  
Souhail Dahmen ◽  
Mohamed Shili Bouhdima ◽  
Morched Ben Amor ◽  
Christ Glorieux
Keyword(s):  
Group Velocity ◽  
Lamb Waves ◽  
Iodic Acid ◽  
Transverse Waves ◽  
Cutoff Frequencies ◽  
Crystallographic Planes ◽  
Zero Group ◽  
Crystallographic Axes ◽  
Symmetric And Antisymmetric Modes ◽  
Lamb Mode

This paper studies the propagation of symmetric and antisymmetric Lamb waves along a 1 mm thick iodic acid plate (HIO3) in the 1–50 MHz frequency range. The Lamb mode propagation along three crystallographic planes was theoretically investigated, for two mutually orthogonal propagation directions. Several frequencies were found that correspond to Lamb modes with zero group velocity (ZGV) and non-null phase velocity values. The first symmetric Lamb mode, S1, was found to possess only one ZGV point, regardless of the propagation direction; higher order symmetric and antisymmetric modes with up to four ZGV points were found, depending on the propagation plane. The dependence of the ZGV frequencies on each elastic constant (c11, c13, c33, c55) of the HIO3 plate material was also investigated by changing the constant values by 5% and 10%. It was found that c33 and c55 affect the number of the ZGV points, while c11 and c13 affect the frequency of the ZGV points. The existence and frequencies of the ZGV points are strongly dependent on the proximity of standing longitudinal and transverse waves at nearby cutoff frequencies.

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