Measurement and analysis of the impact of micrometer scale cracks on the RF performance and reliability of transmission lines

2009 ◽  
Author(s):  
Michael Kruger ◽  
Andreas Middendorf ◽  
Ivan Ndip ◽  
Nils F. Nissen ◽  
Herbert Reichl
Keyword(s):  
Transmission Lines ◽  
Measurement And Analysis ◽  
Rf Performance ◽  
Micrometer Scale ◽  
The Impact

scholarly journals Collapse Analysis of a Transmission Tower-Line System Induced by Ice Shedding

2021 ◽  
Vol 9 ◽  
Author(s):  
Jiaxiang Li ◽  
Biao Wang ◽  
Jian Sun ◽  
Shuhong Wang ◽  
Xiaohong Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Transmission Lines ◽  
Progressive Collapse ◽  
Element Model ◽  
Transmission Tower ◽  
Line System ◽  
Finite Element Software ◽  
Transmission Towers ◽  
Ice Shedding ◽  
The Impact

Ice shedding causes transmission lines to vibrate violently, which induces a sharp increase in the longitudinal unbalanced tension of the lines, even resulting in the progressive collapse of transmission towers in serious cases, which is a common ice-based disaster for transmission tower-line systems. Based on the actual engineering characteristics of a 500 kV transmission line taken as the research object, a finite element model of a two-tower, three-line system is established by commercial ANSYS finite element software. In the modeling process, the uniform mode method is used to introduce the initial defects, and the collapse caused by ice shedding and its influencing parameters are systematically studied. The results show that the higher the ice-shedding height is, the greater the threat of ice shedding to the system; furthermore, the greater the span is, the shorter the insulator length and the greater the dynamic response of the line; the impact of ice shedding should be considered in the design of transmission towers.

scholarly journals Numerical Evaluation of the Effect of Geometric Tolerances on the High-Frequency Performance of Graphene Field-Effect Transistors

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3121
Author(s):  
Monica La Mura ◽  
Patrizia Lamberti ◽  
Vincenzo Tucci
Keyword(s):  
High Frequency ◽  
Communication Systems ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Field Effect Transistors ◽  
Channel Length ◽  
Geometrical Parameters ◽  
Effect Transistor ◽  
Rf Performance ◽  
The Impact

The interest in graphene-based electronics is due to graphene’s great carrier mobility, atomic thickness, resistance to radiation, and tolerance to extreme temperatures. These characteristics enable the development of extremely miniaturized high-performing electronic devices for next-generation radiofrequency (RF) communication systems. The main building block of graphene-based electronics is the graphene-field effect transistor (GFET). An important issue hindering the diffusion of GFET-based circuits on a commercial level is the repeatability of the fabrication process, which affects the uncertainty of both the device geometry and the graphene quality. Concerning the GFET geometrical parameters, it is well known that the channel length is the main factor that determines the high-frequency limitations of a field-effect transistor, and is therefore the parameter that should be better controlled during the fabrication. Nevertheless, other parameters are affected by a fabrication-related tolerance; to understand to which extent an increase of the accuracy of the GFET layout patterning process steps can improve the performance uniformity, their impact on the GFET performance variability should be considered and compared to that of the channel length. In this work, we assess the impact of the fabrication-related tolerances of GFET-base amplifier geometrical parameters on the RF performance, in terms of the amplifier transit frequency and maximum oscillation frequency, by using a design-of-experiments approach.

scholarly journals Hydrodynamic and frictional modulation of deformations in switchable colloidal crystallites

2020 ◽  
Vol 117 (23) ◽  
pp. 12700-12706
Author(s):  
Young Ki Lee ◽  
Xiaoguai Li ◽  
Paris Perdikaris ◽  
John C. Crocker ◽  
Celia Reina ◽  
...  
Keyword(s):  
Principal Component Analysis ◽  
Diffusion Coefficients ◽  
Particle Shape ◽  
Colloidal Crystals ◽  
Principal Component ◽  
Nucleation And Growth ◽  
Spherically Symmetric ◽  
Dynamical Models ◽  
Micrometer Scale ◽  
The Impact

Displacive transformations in colloidal crystals may offer a pathway for increasing the diversity of accessible configurations without the need to engineer particle shape or interaction complexity. To date, binary crystals composed of spherically symmetric particles at specific size ratios have been formed that exhibit floppiness and facile routes for transformation into more rigid structures that are otherwise not accessible by direct nucleation and growth. There is evidence that such transformations, at least at the micrometer scale, are kinetically influenced by concomitant solvent motion that effectively induces hydrodynamic correlations between particles. Here, we study quantitatively the impact of such interactions on the transformation of binary bcc-CsCl analog crystals into close-packed configurations. We first employ principal-component analysis to stratify the explorations of a bcc-CsCl crystallite into orthogonal directions according to displacement. We then compute diffusion coefficients along the different directions using several dynamical models and find that hydrodynamic correlations, depending on their range, can either enhance or dampen collective particle motions. These two distinct effects work synergistically to bias crystallite deformations toward a subset of the available outcomes.

Assessing the Impact of Cost Overrun Causes in Transmission Lines Construction Projects

2020 ◽  
Vol 24 (4) ◽  
pp. 1029-1036 ◽  
Author(s):  
Hai Pham ◽  
Truong-Van Luu ◽  
Soo-Yong Kim ◽  
Duc-Thinh Vien
Keyword(s):  
Transmission Lines ◽  
Construction Projects ◽  
Cost Overrun ◽  
The Impact

scholarly journals RF-MEMS switches with AlN dielectric and their applications

2011 ◽  
Vol 3 (5) ◽  
pp. 509-520 ◽  
Author(s):  
Montserrat Fernández-Bolaños Badía ◽  
Pierre Nicole ◽  
Adrian Mihai Ionescu
Keyword(s):  
Transmission Lines ◽  
Rf Mems ◽  
Beam Steering ◽  
Phase Shifters ◽  
Center Frequency ◽  
Mems Switches ◽  
Rf Mems Switches ◽  
Mems Technology ◽  
Bandwidth Tuning ◽  
Rf Performance

This paper reports on the potential of RF-MEMS technology based on aluminum nitride capacitive dielectric and nickel-suspended membranes to provide RF circuit functions in reconfigurable front-end radios. The RF performance of capacitive switches, distributed MEMS transmission lines (DMTLs) phase shifters for beam steering and tunable filters, including center frequency and bandwidth tuning of bandpass and band-stop filters are presented. Detailed characterization based on S-parameter data demonstrates very promising figures of merit of all fabricated demonstrators from 5 to 40 GHz.

scholarly journals Counts: an outstanding challenge for log-ratio analysis of compositional data in the molecular biosciences

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
David R Lovell ◽  
Xin-Yi Chua ◽  
Annette McGrath
Keyword(s):  
Count Data ◽  
Compositional Data ◽  
Compositional Data Analysis ◽  
Ratio Analysis ◽  
Sequencing Technology ◽  
Scale Invariant ◽  
Measurement And Analysis ◽  
Discrete Nature ◽  
The Impact ◽  
Log Ratio

Abstract Thanks to sequencing technology, modern molecular bioscience datasets are often compositions of counts, e.g. counts of amplicons, mRNAs, etc. While there is growing appreciation that compositional data need special analysis and interpretation, less well understood is the discrete nature of these count compositions (or, as we call them, lattice compositions) and the impact this has on statistical analysis, particularly log-ratio analysis (LRA) of pairwise association. While LRA methods are scale-invariant, count compositional data are not; consequently, the conclusions we draw from LRA of lattice compositions depend on the scale of counts involved. We know that additive variation affects the relative abundance of small counts more than large counts; here we show that additive (quantization) variation comes from the discrete nature of count data itself, as well as (biological) variation in the system under study and (technical) variation from measurement and analysis processes. Variation due to quantization is inevitable, but its impact on conclusions depends on the underlying scale and distribution of counts. We illustrate the different distributions of real molecular bioscience data from different experimental settings to show why it is vital to understand the distributional characteristics of count data before applying and drawing conclusions from compositional data analysis methods.

The impact of total ionizing dose on RF performance of 130 nm PD SOI I/O nMOSFETs

2021 ◽  
Vol 116 ◽  
pp. 114001
Author(s):  
Tiantian Xie ◽  
Hao Ge ◽  
Yinghuan Lv ◽  
Jing Chen
Keyword(s):  
Total Ionizing Dose ◽  
Rf Performance ◽  
The Impact
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