Analysis and Characterization of Embedded Resistors for Wideband Applications

2005 ◽  
Author(s):  
Albert C. W. Lu ◽  
L. L. Wai ◽  
W. Fan ◽  
Stephen C. K. Wong ◽  
Toshio Yamazaki ◽  
...  
Keyword(s):  
High Frequency ◽  
Research Work ◽  
Low Frequency ◽  
Limited Attention ◽  
Organic Substrates ◽  
High Frequencies ◽  
Surface Mount ◽  
Discrete Surface ◽  
Embedded Resistors

This paper will describe the high-frequency analysis and characterization of embedded resistors fabricated in organic substrates. Although embedded resistors have been widely used in organic substrates, detailed analysis and characterization at high frequencies have received very limited attention. Majority of previous research work focuses on low frequency performance and manufacturing considerations. In this research work, a novel embedded resistor fabrication technique was employed to allow design on demand implementation of resistors. Analysis and characterization were carried out for frequencies up to 20 GHz, along with a comparison between embedded resistors and discrete surface mount resistors. It can be deduced that the degraded performance in the discrete implementation occurs above 1 GHz and is mainly attributed to surface mount parasitics. Embedded resistors, in contrast, offer significantly better broadband performance up to 20 GHz, in spite of inferior tolerances within 20%. This results show that embedded resistors not only achieve improved area utilization but also greatly improved high-frequency performance.

scholarly journals Rheology of rounded mammalian cells over continuous high-frequencies

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gotthold Fläschner ◽  
Cosmin I. Roman ◽  
Nico Strohmeyer ◽  
David Martinez-Martin ◽  
Daniel J. Müller
Keyword(s):  
High Frequency ◽  
Mammalian Cells ◽  
Mechanical Response ◽  
Cell Mass ◽  
Low Frequency ◽  
Mass Measurements ◽  
High Frequencies ◽  
Polymer Relaxation ◽  
Continuous Frequency ◽  
Rheological Experiments

AbstractUnderstanding the viscoelastic properties of living cells and their relation to cell state and morphology remains challenging. Low-frequency mechanical perturbations have contributed considerably to the understanding, yet higher frequencies promise to elucidate the link between cellular and molecular properties, such as polymer relaxation and monomer reaction kinetics. Here, we introduce an assay, that uses an actuated microcantilever to confine a single, rounded cell on a second microcantilever, which measures the cell mechanical response across a continuous frequency range ≈ 1–40 kHz. Cell mass measurements and optical microscopy are co-implemented. The fast, high-frequency measurements are applied to rheologically monitor cellular stiffening. We find that the rheology of rounded HeLa cells obeys a cytoskeleton-dependent power-law, similar to spread cells. Cell size and viscoelasticity are uncorrelated, which contrasts an assumption based on the Laplace law. Together with the presented theory of mechanical de-embedding, our assay is generally applicable to other rheological experiments.

scholarly journals ANALYSIS OF HIGH-FREQUENCY C-CORE MAGNETIC FLUX LEAKAGES FOR BONE TUMOR WITH INDUCTION HEATING BY USING MULTI-COIL

2019 ◽  
Author(s):  
Metharak Jokpudsa ◽  
Supawat Kotchapradit ◽  
Chanchai Thongsopa ◽  
Thanaset Thosdeekoraphat
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Tumor Tissue ◽  
Low Frequency ◽  
Heat Energy ◽  
High Frequencies ◽  
Frequency Magnetic Field ◽  
High Frequency Magnetic Field ◽  
The Magnetic Field ◽  
Flux Leakage

High-frequency magnetic field has been developed pervasively. The induction of heat from the magnetic field can help to treat tumor tissue to a certain extent. Normally, treatment by the low-frequency magnetic field needed to be combined with magnetic substances. To assist in the induction of magnetic fields and reduce flux leakage. However, there are studies that have found that high frequencies can cause heat to tumor tissue. In this paper present, a new magnetic application will focus on the analysis of the high-frequency magnetic nickel core with multi-coil. In order to focus the heat energy using a high-frequency magnetic field into the tumor tissue. The magnetic coil was excited by 915 MHz signal and the combination of tissues used are muscle, bone, and tumor. The magnetic power on the heating predicted by the analytical model, the power loss density (2.98e-6 w/m3) was analyzed using the CST microwave studio.

An Oscillating Disk Rheometer for Measuring Dynamic Properties during Vulcanization

1963 ◽  
Vol 36 (2) ◽  
pp. 451-458 ◽  
Author(s):  
G. E. Decker ◽  
R. W. Wise ◽  
D. Guerry
Keyword(s):  
Small Angle ◽  
High Frequency ◽  
Unique Feature ◽  
Dynamic Properties ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Stress And Strain ◽  
Loss Angle ◽  
High Frequencies ◽  
Rubber Specimen

Abstract A forced oscillating-disk rheometer has been developed which can measure both the low and high frequency dynamic properties of a rubber specimen throughout vulcanization. It may also be used to measure the rheological properties of unvulcanized polymers. The instrument consists of a cone-shaped disk which is embedded in the rubber specimen and oscillated through a small angle while the specimen is heated under pressure. Both stress and strain in terms of torque and displacement, respectively, are measured by appropriate transducers and recorded on an oscillograph. Provisions are made for changing both frequency and strain. At low frequency, the instrument is a convenient tool for determining all of the curing parameters of a rubber specimen. At high frequencies, the change in the dynamic properties of a rubber specimen throughout vulcanization may be continuously followed. A unique feature of the rheometer is that the loss angle may be determined which permits resolution of the measured dynamic stiffness into its elastic and viscous components.

Mechanisms of Noise Transmission through Helicopter Gearbox Support Struts

1994 ◽  
Vol 116 (4) ◽  
pp. 548-554 ◽  
Author(s):  
M. J. Brennan ◽  
R. J. Pinnington ◽  
S. J. Elliott
Keyword(s):  
High Frequency ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Structural Members ◽  
Vibration Transmission ◽  
Gear Noise ◽  
High Frequencies ◽  
Passive Vibration Isolation ◽  
In Series ◽  
Frequency Behavior

Helicopter gearbox support struts are structural members designed to take large compressive and tensile mechanical loads. They also act as vibration transmission paths connecting the major noise and vibration generators of the main rotor and gearbox to the fuselage and cabin. In this paper the mechanisms of vibration transmission through these struts are examined. The differences between the low frequency behavior that is important in the transmission of the rotor vibrations, and the high frequency behavior that is important in the transmission of gear noise are discussed. A flexible element is introduced in series with the strut, and the limitations of this simple passive measure in attenuating longitudinal and flexural vibrations are highlighted. The analysis shows that there is a difference in the mechanisms of vibration transmission between low and high frequencies, and that there are difficulties in applying effective passive vibration isolation measures to this system.

scholarly journals OBTAINING HYSTERESIS LOOPS AT LOW FREQUENCY FOR CHARACTERIZATION OF MATERIALS TO BE USED IN BIOMEDICAL APPLICATIONS

2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Atika Arshad ◽  
Rumana Tasnim ◽  
Sheroz Khan ◽  
A.H.M Zahirul Alam
Keyword(s):  
Magnetic Field ◽  
Magnetic Properties ◽  
Hysteresis Loop ◽  
Magnetic Materials ◽  
Research Work ◽  
Low Frequency ◽  
Hysteresis Loops ◽  
Simple Circuit ◽  
Characterization Of Materials

The promising development of magnetic sensors in biomedical field demands an appropriate level of understanding of the magnetic properties of the materials used in their fabrication. To date only few of the types of magnetic materials are encountered where their magnetic properties, characterization techniques and magnetization behavior are yet to be explored more suitably in the light of their applications. This research work studies the characterization of materials by using a cost effective and simple circuit consisting of inductive transducer and an OP-AMP as a voltage integrator. In this approach the circuit was simulated using PSPICE and experiments have been conducted to achieve the desired results. The simulation and experimental results are obtained for three test materials namely iron, steel and plastic. The novelty lies in applying the simple circuit for material testing and characterization via obtaining simulation results and validating these results through experiment. The magnetic properties in low external magnetic field are studied with materials under test. The magnetization effect of a magneto-inductive sensor is detected in low frequency range for different magnetic core materials. The results have shown magnetization behaviour of magnetic materials due to the variation of permeability and magnetism. The resulted hysteresis loops appeared to have different shapes for different materials. The magnetic hysteresis loop found for iron core demonstrated a bigger coercive force and larger reversals of magnetism than these of steel core, thus obtaining its magnetic saturation at a larger magnetic field strength. The shape of the hysteresis loop itself is found to be varying upon the nature of the material in use. The resulted magnetization behaviors of the materials proved their possible applicability for use in sensing devices. The key concern of this work is found upon selecting the appropriate magnetic materials at the desired frequency of operation for magneto resistive applications, magneto-resistive sensors and for an extensive range of biomedical sensor application. 

scholarly journals High-frequency Turnover in Pulsar Spectra

2004 ◽  
Vol 218 ◽  
pp. 339-340 ◽  
Author(s):  
J. Kijak ◽  
O. Maron
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
High Frequencies

Spectra of several pulsars with turnover at unusually high frequencies ∼ 1 GHz are presented. These are relatively young pulsars with DM typically larger than for pulsars showing a low-frequency turnover.

scholarly journals A possible mechanism for flattening of pulsar spectra at high frequencies

2000 ◽  
Vol 177 ◽  
pp. 395-396
Author(s):  
I.F. Malov
Keyword(s):  
Spectral Index ◽  
High Frequency ◽  
Linear Part ◽  
Low Frequency ◽  
Usual Model ◽  
High Frequencies ◽  
Unusual Behaviour ◽  
Curvature Radiation

Pulsar spectra have three characteristic parts: a low frequency turnover (the region of the maximum), a linear part with a constant spectral index, and a high frequency cut-off (after it the spectrum becomes considerably steeper) (Malofeev et al. 1994). These three parts can be described in the frame of the usual model of curvature radiation (Malov 1979; Ochelkov & Usov 1984; Kuz’min & Solov’ev 1986; Malov & Malofeev 1991). Kramer et al. (1997) have found a flattening in the spectra of 4 pulsars at frequencies above 30 GHz. It cannot be understood in such model. We propose the possible explanation for the unusual behaviour of these spectra.

Electroencephalographic and blood parameters changes in anaesthetised goats subjected to slaughter without stunning and slaughter following different electrical stunning methods

2019 ◽  
Vol 59 (5) ◽  
pp. 849
Author(s):  
A. B. Sabow ◽  
Y. M. Goh ◽  
I. Zulkifli ◽  
M. Z. Ab Kadir ◽  
U. Kaka ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Adverse Effects ◽  
Meat Quality ◽  
Tissue Damage ◽  
High Frequency ◽  
Sensory Input ◽  
Low Frequency ◽  
Blood Parameters ◽  
Brain Electrical Activity ◽  
High Frequencies

Electrical stunning is the most widely used stunning method for sheep and goats. Because low frequency head-to-back electrical stunning induces cardiac arrest, it is non-compliant with halal requirements. In addition, conventional head-only electrical stunning method can have adverse effects on carcass and meat quality. To address these issues high-frequency electrical stunning systems were developed. High frequency head-to-back removes the potential for pain and distress compared with non-stunned slaughter and does not induce cardiac arrest like low frequency head-to-back stunning making it appropriate for halal. However, this claim is yet to be proven through a comprehensive neurophysiological study. Thus, the present study examined the effects of different pre-slaughter electrical stunning methods and slaughter without stunning on electroencephalographic and blood biochemistry changes. Thirty-two male Boer crossbred bucks were distributed into four groups of eight animals each and subjected to slaughter without stunning (SWS), low frequency head-only (LFHO) and low frequency head-to-back (LFHB) or high frequency head-to-back electrical stunning (HFHB). Slaughtering of animals with or without stunning was performed under minimal anaesthesia. Based on electroencephalograph results, at slaughter, the SWS animals showed an increase in brain electrical activity, which is consistent with the presence of post slaughter noxious sensory input associated with tissue damage. Meanwhile the electroencephalograph activities decreased immediately after application of electrical stunning in all animals, suggesting that they were insensible to pain during and after the neck cut. Electrical brain activities for goats subjected to HFHB were comparable to those for LFHO and those for LFHB. The percentage of animals that exhibited severe clonic activity was significantly lower after LFHB or HFHB stunning compared with LFHO. The concentrations of catecholamines and hyperglycemia in electrically stunned goats were higher compared with those from SWS. It was observed that LFHB caused cardiac arrest in all goats whereas all HFHB goats had no cardiac arrest. High frequency head-to-back electrical stunning may be an improvement on non-stunned slaughter and has advantages for meat quality. However, stunning effectiveness after head-to-back electrical stunning with high frequencies needs to be evaluated under industrial conditions before any recommendation is given.

Permeability and borehole Stoneley waves: Comparison between experiment and theory

Geophysics ◽  
1989 ◽  
Vol 54 (1) ◽  
pp. 66-75 ◽  
Author(s):  
Kenneth W. Winkler ◽  
Hsui‐Lin Liu ◽  
David Linton Johnson
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Theoretical Models ◽  
Oil Field ◽  
Stoneley Wave ◽  
Biot Theory ◽  
Frequency Dependent ◽  
Low Frequencies ◽  
High Frequencies ◽  
Theoretical Predictions

We performed laboratory experiments to evaluate theoretical models of borehole. Stoneley wave propagation in permeable materials. A Berea sandstone and synthetic samples made of cemented glass beads were saturated with silicone oils. We measured both velocity and attenuation over a frequency band from 10 kHz to 90 kHz. Our theoretical modeling incorporated Biot theory and Deresiewicz‐Skalak boundary conditions into a cylindrical geometry and included frequency‐dependent permeability. By varying the viscosity of the saturating pore fluid, we were able to study both low‐frequency and high‐frequency regions of Biot theory, as well as the intermediate transition zone. In both low‐frequency and high‐frequency regions of the theory, we obtained excellent agreement between experimental observations and theoretical predictions. Velocity and attenuation (1/Q) are frequency‐dependent, especially at low frequencies. Also at low frequencies, velocity decreases and attenuation increases with increasing fluid mobility (permeability/viscosity). More complicated behavior is observed at high frequencies. These results support recent observations from the oil field suggesting that Stoneley wave velocity and attenuation may be indicative of formation permeability.

scholarly journals Detection and characterization of small superficially located focal liver lesions by contrast-enhanced ultrasound with high frequency transducers

2017 ◽  
Vol 19 (4) ◽  
pp. 349 ◽  
Author(s):  
Wen-Ping Wang ◽  
Yi Dong ◽  
Jiaying Cao ◽  
Feng Mao ◽  
Yadan Xu ◽  
...  
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Focal Liver Lesions ◽  
Liver Lesions ◽  
Contrast Enhanced Ultrasound ◽  
Contrast Enhanced ◽  
Frequency Transducer ◽  
High Frequency Transducer ◽  
Sensitivity Specificity

Aim: To evaluate the benefits of contrast-enhanced ultrasound (CEUS) with high frequency transducers in the detection and characterization of small superficially located focal liver lesions (FLLs).Material and methods: From January 2015 to October 2016, 27 superficial FLLs detected by MRI were examined, first with the low frequency convex transducer (1-5 MHz) and afterwards with a high frequency transducer (7.5-12 MHz). High frequency dynamic CEUS was performed after a bolus injection of 2.4 ml SonoVue®. FLLs were confirmed by histopathology after surgery (n=18) or ultrasound guided 18-gauge core-needle biopsy (n=8), or by MRI follow-up (n =1).Results: The mean diameter of FLLs was 10.5±3.1 mm, and meandepth was 6.2±5.3 mm. While using a high frequency transducerthe detection rate of FLLs (100%, 27/27) was significantly higher than low frequency transducer (25.9%, 7/27) (p<0.05). The overall sensitivity, specificity and diagnostic accuracy were significantly improved by CEUS with a high frequency transducer (sensitivity 88.9%; specificity 92.6%; accuracy 96.2%).Conclusion: Combining CEUS with the performance of high-frequency transducers is a promising technique to improve the detection and accurate diagnosis of small and superficial FLLs appearing indistinctive on BMUS.

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