PHYSICAL MECHANISMS OF OAE GENERATION AND PROPAGATION: THE HYDRODYNAMIC APPROACH

Author(s):  
A. VETEŠNÍK ◽  
R. NOBILI ◽  
A. W. GUMMER
Author(s):  
Koenraad G F Janssens ◽  
Omer Van der Biest ◽  
Jan Vanhellemont ◽  
Herman E Maes ◽  
Robert Hull

There is a growing need for elastic strain characterization techniques with submicrometer resolution in several engineering technologies. In advanced material science and engineering the quantitative knowledge of elastic strain, e.g. at small particles or fibers in reinforced composite materials, can lead to a better understanding of the underlying physical mechanisms and thus to an optimization of material production processes. In advanced semiconductor processing and technology, the current size of micro-electronic devices requires an increasing effort in the analysis and characterization of localized strain. More than 30 years have passed since electron diffraction contrast imaging (EDCI) was used for the first time to analyse the local strain field in and around small coherent precipitates1. In later stages the same technique was used to identify straight dislocations by simulating the EDCI contrast resulting from the strain field of a dislocation and comparing it with experimental observations. Since then the technique was developed further by a small number of researchers, most of whom programmed their own dedicated algorithms to solve the problem of EDCI image simulation for the particular problem they were studying at the time.


2000 ◽  
Vol 660 ◽  
Author(s):  
Thomas M. Brown ◽  
Ian S. Millard ◽  
David J. Lacey ◽  
Jeremy H. Burroughes ◽  
Richard H. Friend ◽  
...  

ABSTRACTThe semiconducting-polymer/injecting-electrode heterojunction plays a crucial part in the operation of organic solid state devices. In polymer light-emitting diodes (LEDs), a common fundamental structure employed is Indium-Tin-Oxide/Polymer/Al. However, in order to fabricate efficient devices, alterations to this basic structure have to be carried out. The insertion of thin layers, between the electrodes and the emitting polymer, has been shown to greatly enhance LED performance, although the physical mechanisms underlying this effect remain unclear. Here, we use electro-absorption measurements of the built-in potential to monitor shifts in the barrier height at the electrode/polymer interface. We demonstrate that the main advantage brought about by inter-layers, such as poly(ethylenedioxythiophene)/poly(styrene sulphonic acid) (PEDOT:PSS) at the anode and Ca, LiF and CsF at the cathode, is a marked reduction of the barrier to carrier injection. The electro- absorption results also correlate with the electroluminescent characteristics of the LEDs.


1998 ◽  
Author(s):  
J. Benbrik ◽  
G. Rolland ◽  
P. Perdu ◽  
B. Benteo ◽  
M. Casari ◽  
...  

Abstract Focused Ion Beam is commonly used for IC repairs and modifications. However, FIB operation may also induce a damaging impact which can takes place far from the working area due to the charge-up phenomenon. A complete characterization joined to an in-depth understanding of the physical phenomena arising from FIB irradiation is therefore necessary to take into account spurious FIB induced effects and to enhance the success of FIB modifications. In this paper, we present the effects of FIB irradiation on the electrical DC performances of different electronic devices such as nMOS and pMOS transistors, CMOS inverters, PN junctions and bipolar transistors. From the observed behavior of the DC characteristics evolution of the devices, some suggestions about physical mechanisms inducing the electrical degradation are proposed.


Author(s):  
Anne E. Gattiker ◽  
Phil Nigh ◽  
Wojciech Maly

Abstract This article provides an analysis of a class of failures observed during the SEMATECH-sponsored Test Methods Experiment. The analysis focuses on use of test-based failure analysis and IDDQ signature analysis to gain insight into the physical mechanisms underlying such subtle failures. In doing so, the analysis highlights techniques for understanding failure mechanisms using only tester data. In the experiment, multiple test methods were applied to a 0.45 micrometer effective channel length ASIC. Specifically, ICs that change test behavior from before to after burn-in are studied to understand the physical nature of the mechanism underlying their failure. Examples of the insights provided by the test-based analysis include identifying cases where there are multiple or complex defects and distinguishing cases where the defect type is likely to be a short versus an open and determining if the defect is marginal. These insights can be helpful for successful failure analysis.


Author(s):  
Andrew Clarke

This introduces the subject, laying out the organisation of the book and emphasising the importance of both simple underlying physical mechanisms and evolutionary variability to thermal ecology. It distinguishes physical mechanism from statistical description, and the importance of evolutionary processes in comparisons across species.


2019 ◽  
Vol 23 (4) ◽  
pp. 2015-2039 ◽  
Author(s):  
William Quinton ◽  
Aaron Berg ◽  
Michael Braverman ◽  
Olivia Carpino ◽  
Laura Chasmer ◽  
...  

Abstract. Scotty Creek, Northwest Territories (NWT), Canada, has been the focus of hydrological research for nearly three decades. Over this period, field and modelling studies have generated new insights into the thermal and physical mechanisms governing the flux and storage of water in the wetland-dominated regions of discontinuous permafrost that characterises much of the Canadian and circumpolar subarctic. Research at Scotty Creek has coincided with a period of unprecedented climate warming, permafrost thaw, and resulting land cover transformations including the expansion of wetland areas and loss of forests. This paper (1) synthesises field and modelling studies at Scotty Creek, (2) highlights the key insights of these studies on the major water flux and storage processes operating within and between the major land cover types, and (3) provides insights into the rate and pattern of the permafrost-thaw-induced land cover change and how such changes will affect the hydrology and water resources of the study region.


Sign in / Sign up

Export Citation Format

Share Document