Adsorption induced differential surface stress versus adsorption induced resonance frequency change: a comparison

2005 ◽  
Author(s):  
J. Amirola ◽  
A. Rodriguez ◽  
L. Castaner ◽  
J. Lozano ◽  
F. J. Gutierrez ◽  
...  
Keyword(s):  
Resonance Frequency ◽  
Surface Stress ◽  
Frequency Change

Stimulated electromagnetic shock radiation (SESR) in frequency-dispersive media

1977 ◽  
Vol 55 (17) ◽  
pp. 1499-1509 ◽  
Author(s):  
S. Schneider ◽  
R. Spitzer
Keyword(s):  
Resonance Frequency ◽  
Energy Levels ◽  
Stimulated Emission ◽  
Dispersive Media ◽  
Electron Trajectory ◽  
Frequency Change ◽  
Electromagnetic Shock ◽  
Frequency Changes ◽  
Shock Frequency ◽  
Shock Fronts

The interaction in a frequency-dispersive medium of a coherent electromagnetic wave with an electron moving faster than a critical (Mach) speed produces electromagnetic radiation with novel characteristics. Theory predicts emission of intense radiation in the form of shock fronts at specific angles from the electron trajectory. The shock fronts are correlated with specific frequencies shifted significantly from that of the incident wave. We have named this effect stimulated electromagnetic shock radiation (SESR). The shock frequencies depend dynamically on the populations of the energy levels that give rise to the medium resonances. A given shock frequency changes from below to above the resonance frequency of the medium with which it is associated as the populations of the two energy levels corresponding to this resonance frequency change from an equilibrium distribution to an inverted one. This dynamic resonance crossing points to the possibility of new synergisms between SESR emission and stimulated emission between discrete levels.

Resonance Frequency Change in Microcantilever-Based Sensor due to Humidity Variation

2013 ◽  
Vol 737 ◽  
pp. 176-182 ◽  
Author(s):  
Ratno Nuryadi ◽  
Arko Djajadi ◽  
Reyhan Adiel ◽  
Lia Aprilia ◽  
Nuning Aisah
Keyword(s):  
Environmental Monitoring ◽  
Resonance Frequency ◽  
Rapid Detection ◽  
High Sensitivity ◽  
Spring Constant ◽  
Dynamic Mode ◽  
Frequency Change ◽  
The Many

Microcantilever-based sensors have attracted interest in the last decade because of their small size, rapid detection and high sensitivity. This sensor can be applied in the many fields, i.e. physics, chemistry, biology, biochemistry, medical, and environment. In this paper, we describe microcantilever-based sensor for environmental monitoring, especially for a humidity detection. This sensor was operated in dynamic mode where a change in mass or spring constant of the microcantilever provides the resonance frequency change. Here, a change of humidity is detected by the resonance frequency and the amplitude changes. It is found that the increase in the humidity causes the decreasing the resonance frequency but increasing the amplitude. This result opens up the possibility of the humidity detection using microcantilever-based sensor.

scholarly journals Delaminated Domain Location of CFRP Laminated Beams Using Anti-Resonance Frequency Change.

2001 ◽  
Vol 67 (664) ◽  
pp. 1929-1935
Author(s):  
Takaomi INADA ◽  
Yoshinobu SHIMAMURA ◽  
Akira TODOROKI ◽  
Hideo KOBAYASHI
Keyword(s):  
Resonance Frequency ◽  
Frequency Change ◽  
Laminated Beams

Preparation-Free Method for Detecting Escherichia coli O157:H7 in the Presence of Spinach, Spring Lettuce Mix, and Ground Beef Particulates

2007 ◽  
Vol 70 (11) ◽  
pp. 2651-2655 ◽  
Author(s):  
DAVID MARALDO ◽  
RAJ MUTHARASAN
Keyword(s):  
Escherichia Coli ◽  
Resonance Frequency ◽  
Ground Beef ◽  
Sensor Response ◽  
Frequency Change ◽  
Escherichia Coli O157 ◽  
Food Matrix ◽  
Sample Container ◽  
Food Matrices ◽  
Frequency Changes

We show the detection of 100 cells per ml of Escherichia coli O157:H7 in the presence of spinach, spring lettuce mix, and ground beef washes and particulate matter with piezoelectric-excited millimeter-sized cantilever (PEMC) sensors. The PEMC sensors (sensing area, 2 mm2) were immobilized with polyclonal antibody specific to E. coli O157:H7 (EC) and were exposed to 10 aqueous washes of locally purchased spinach, spring lettuce mix, and ground beef for testing if EC was present. Absence of resonance frequency shift indicated that EC was not present in the 30 samples tested. Following the last sample in each food matrix, 1,000 cells per ml of EC were spiked into the sample container, and resonance frequency change was monitored. The total resonance frequency change was 880 ± 5, 1,875 ± 8, and 1,417 ± 4 Hz for spinach, spring lettuce mix, and ground beef, respectively. A mixture of the three food matrices spiked with 100 cells per ml of EC gave a sensor response of 260 ± 15 Hz. The resonance frequency changes are approximately 40% lower than our previously reported study on ground beef. It is suggested that the reduction in sensitivity is due to differences in pathogen adherence to food matrices, which affects target binding to the sensor surface. We conclude that detection selectivity is conserved in the three food matrices examined and that the magnitude of sensor response is a function of the food matrix.

Effect of surface stress on microcantilever resonance frequency during water adsorption: influence of microcantilever dimensions

2014 ◽  
Vol 146 ◽  
pp. 79-82 ◽  
Author(s):  
K. Lakshmoji ◽  
K. Prabakar ◽  
S. Tripura Sundari ◽  
J. Jayapandian ◽  
C.S. Sundar
Keyword(s):  
Resonance Frequency ◽  
Surface Stress ◽  
Water Adsorption ◽  
Effect Of Surface

ANALYSIS OF VISCOELASTICITY OF HUMAN SKIN FOR PREVENTION OF PRESSURE ULCERS

2008 ◽  
Vol 08 (01) ◽  
pp. 33-43 ◽  
Author(s):  
YOKO AKIYAMA ◽  
YOSHIRO YAMAMOTO ◽  
YUSUKE DOI ◽  
YOSHINOBU IZUMI ◽  
SHIGEHIRO NISHIJIMA ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Elastic Modulus ◽  
Resonance Frequency ◽  
Human Skin ◽  
Strain Distribution ◽  
Pressure Ulcers ◽  
Subcutaneous Tissue ◽  
Frequency Change ◽  
The Finite Element Method ◽  
The Difference

Change in viscoelasticity of human skin with aging is evaluated by measurement of deformation under suction and of resonance frequency change under probe indentation. The elastic modulus of human skin measured by suction increases with aging, but that measured by resonance frequency change decreases; the difference is considered to be caused by the difference in measured depth region of the human skin. In order to clarify the depth region which can be measured by each technique, strain distribution is calculated by the finite element method (FEM). The results show that the epidermis is mainly deformed by the skin suction method, whereas the dermis and subcutaneous tissue are mainly deformed by measurement of resonance frequency change. For confirmation of FEM results, skin models made of silicone rubber are prepared and measured by the two methods. Viscoelasticity in the depth region from the surface to several hundred micrometers of the material is obtained by the skin suction method, while that in the region from several millimeters to several centimeters is obtained by the resonance frequency change. Based on these results, it is observed that the elastic modulus of epidermis tends to increase with aging while that of dermis and subcutaneous tissue tends to decrease, thus causing pressure ulcers.

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