scholarly journals Mass determination and sensitivity based on resonance frequency changes of the higher flexural modes of cantilever sensors

2011 ◽  
Vol 82 (3) ◽  
pp. 035108 ◽  
Author(s):  
John D. Parkin ◽  
Georg Hähner
Keyword(s):  
Resonance Frequency ◽  
Mass Determination ◽  
Cantilever Sensors ◽  
Frequency Changes

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.

Determining resonance frequency changes due to bore irregularities in woodwinds

1998 ◽  
Vol 103 (5) ◽  
pp. 2874-2874
Author(s):  
Cornelis J. Nederveen ◽  
Jean‐Pierre Dalmont
Keyword(s):  
Resonance Frequency ◽  
Frequency Changes

K-2325 Delamination Identification of CFRP Laminated Structures Using Resonance and Anti-resonance Frequency Changes

2001 ◽  
Vol V.01.1 (0) ◽  
pp. 351-352
Author(s):  
Takaomi INADA ◽  
Yoshinobu SHIMAMURA ◽  
Akira TODOROKI ◽  
Hideo KOBAYASHI
Keyword(s):  
Resonance Frequency ◽  
Frequency Changes ◽  
Laminated Structures

scholarly journals Opto-thermally Excited Fabry-Perot Resonance Frequency Behaviors of Clamped Circular Graphene Membrane

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 563
Author(s):  
Fu-Tao Shi ◽  
Shang-Chun Fan ◽  
Cheng Li ◽  
Zi-Ang Li
Keyword(s):  
Optical Fiber ◽  
Resonance Frequency ◽  
Environmental Temperature ◽  
Membrane Properties ◽  
Circular Membrane ◽  
Graphene Membrane ◽  
Film Boundary ◽  
Fabry Perot ◽  
Mechanical Factors ◽  
Frequency Changes

An opto-thermally excited optical fiber Fabry-Perot (F-P) resonant probe with suspended clamped circular graphene diaphragm is presented in this paper. Then, the dependence of resonance frequency behaviors of graphene diaphragm upon opto-mechanical factors including membrane properties, laser excitation parameters and film boundary conditions are investigated via COMSOL Multiphysics simulation. The results show that the radius and thickness of membrane will linearly affect the optical fiber light-induced temperature distribution, thus resulting in rapidly decreasing resonance frequency changes with the radius-to-thickness ratio. Moreover, the prestress can be regulated in the range of 108 Pa to 109 Pa by altering the environmental temperature with a scale factor of 14.2 MPa/K. It is important to note that the availability of F-P resonant probe with a defective clamped circular graphene membrane can be improved notably by fabricating the defected circular membrane to a double-end clamped beam, which gives a broader perspective to characterize the resonance performance of opto-thermally excited F-P resonators.

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.

Modeling Molecular Interactions Arising From Adsorbed Biological Species on the Microcantilever Biosensor Surface

2006 ◽  
Author(s):  
Mana Afshari ◽  
Nader Jalili
Keyword(s):  
Resonance Frequency ◽  
Surface Stress ◽  
Flexural Rigidity ◽  
Mathematical Expression ◽  
Longitudinal Force ◽  
Biological Species ◽  
Modeling Framework ◽  
Frequency Changes ◽  
Microcantilever Beam ◽  
Effect Of Surface

This paper presents a general framework for modeling resonance frequency changes induced due to the surface stress arising from the adsorption of biological species on the surface of the microcantilever biosensors. Very few works have dealt with the effect of surface stress on the resonance frequency shifts of microcantilevers and mainly assume a simple model for the vibrating microcantilever beam. In the proposed modeling framework, the nonlinear terms due to beam's flexural rigidity from macro- to micro-scale as well as varying nature of the longitudinal force resulting from the surface stress are considered. It is demonstrated that through applying the mathematical expression formulated in this paper, desired biological species can be easily and accurately detected.

Mass Determination by Direct Measurement of Electron Scattering

1975 ◽  
Vol 33 ◽  
pp. 240-241
Author(s):  
M. K. Lamvik ◽  
A. V. Crewe
Keyword(s):  
Cross Section ◽  
Electron Scattering ◽  
Mass Density ◽  
Variable Mass ◽  
Scattering Cross Section ◽  
Mass Determination ◽  
Number Density ◽  
Cross Sectional ◽  
Thin Slice ◽  
Scattering Cross

If a molecule or atom of material has molecular weight A, the number density of such units is given by n=Nρ/A, where N is Avogadro's number and ρ is the mass density of the material. The amount of scattering from each unit can be written by assigning an imaginary cross-sectional area σ to each unit. If the current I0 is incident on a thin slice of material of thickness z and the current I remains unscattered, then the scattering cross-section σ is defined by I=IOnσz. For a specimen that is not thin, the definition must be applied to each imaginary thin slice and the result I/I0 =exp(-nσz) is obtained by integrating over the whole thickness. It is useful to separate the variable mass-thickness w=ρz from the other factors to yield I/I0 =exp(-sw), where s=Nσ/A is the scattering cross-section per unit mass.

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