scholarly journals Clamped-end effect on static detection signals of DNA-microcantilever

2021 ◽  
Vol 42 (10) ◽  
pp. 1423-1438
Author(s):  
Junzheng Wu ◽  
Nenghui Zhang
Keyword(s):  
Governing Equation ◽  
Great Influence ◽  
End Effect ◽  
Dna Adsorption ◽  
Tangential Load ◽  
Concentrated Load ◽  
Microcantilever Sensors ◽  
Shift Effect ◽  
Curvature Distribution ◽  
Static Detection

AbstractBoundary constraint induced inhomogeneous effects are important for mechanical responses of nano/micro-devices. For microcantilever sensors, the clamped-end constraint induced inhomogeneous effect of static deformation, so called the clamped-end effect, has great influence on the detection signals. This paper is devoted to developing an alternative mechanical model to characterize the clamped-end effect on the static detection signals of the DNA-microcantilever. Different from the previous concentrated load models, the DNA adsorption is taken as an equivalent uniformly distributed tangential load on the substrate upper surface, which exactly satisfies the zero force boundary condition at the free-end. Thereout, a variable coefficient differential governing equation describing the non-uniform deformation of the DNA-microcantilever induced by the clamped-end constraint is established by using the principle of minimum potential energy. By reducing the order of the governing equation, the analytical solutions of the curvature distribution and static bending deflection are obtained. By comparing with the previous approximate surface stress models, the clamped-end effect on the static deflection signals is discussed, and the importance of the neutral axis shift effect is also illustrated for the asymmetric laminated microcantilever.

A Circular Elastic Cylinder Under Extension

2011 ◽  
Vol 27 (3) ◽  
pp. 399-407 ◽  
Author(s):  
W.-D. Tseng ◽  
J.-Q. Tarn
Keyword(s):  
Transversely Isotropic ◽  
Elastic Cylinder ◽  
Axisymmetric Deformation ◽  
Axial Stiffness ◽  
Stress Distributions ◽  
End Effect ◽  
Rigorous Solution ◽  
Concentrated Load ◽  
End Conditions ◽  
Space Formalism

ABSTRACTAnalysis of deformation and stress field in a circular elastic cylinder under the extension is presented, with emphasis on the end effect. The problem is formulated on the basis of the state space formalism for axisymmetric deformation of transversely isotropic materials. A rigorous solution that satisfies the prescribed end conditions is determined by using symplectic eigenfunction expansion, thereby, the applicability of the Saint-Venant solution is examined. The results show that the end effect is significant but confined to a local region near the base of the cylinder where the end plane is perfectly bonded or subjected to a concentrated load. As the axial stiffness increases, the end effect on the stress state increases at the loaded end but decreases at the bonded end. The displacement and stress distributions across the section are uniform throughout the length of the cylinder except near the ends.

An Arbitrary Tangential Load Underneath a Smooth Circular Punch

1990 ◽  
Vol 57 (3) ◽  
pp. 596-599 ◽  
Author(s):  
V. I. Fabrikant
Keyword(s):  
Exact Solution ◽  
Transversely Isotropic ◽  
Elastic Half Space ◽  
Reciprocal Theorem ◽  
Tangential Load ◽  
Concentrated Load ◽  
Circular Punch ◽  
Angular Displacements ◽  
The Reciprocal Theorem ◽  
First Time

The problem of a smooth circular punch penetrating a transversely isotropic elastic half space and interacting with an arbitrarily located tangential concentrated load is considered. For the first time, a closed-form exact solution is obtained for the stress distribution under the punch as well as for the linear and angular displacements of the punch. The solution is based on the results previously obtained by the author and combined with the reciprocal theorem. A numerical example is presented as an illustration.

scholarly journals Theoretical Analysis for Bending of Single-Stranded DNA Adsorption on Microcantilever Sensors

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2812 ◽  
Author(s):  
Zou-Qing Tan ◽  
Yang-Chun Chen ◽  
Neng-Hui Zhang
Keyword(s):  
Mechanical Energy ◽  
Minimum Principle ◽  
Mean Field Theory ◽  
Mean Field ◽  
Radius Of Curvature ◽  
Label Free ◽  
Dna Adsorption ◽  
Single Stranded Dna ◽  
Microcantilever Sensors ◽  
Volume Energy

An energy-based model is presented to establish the bending deformation of microcantilever beams induced by single-stranded DNA (ssDNA) adsorption. The total free energy of the DNA-microcantilever sensor was obtained by considering the excluded-volume energy and the polymer stretching energy of DNA chains from mean-field theory, and the mechanical energy of three non-biological layers. The radius of curvature and deflection of the cantilever were determined through the minimum principle of energy. The efficiency of the present model was confirmed through comparison with experimental data. The effects of length, grafting density, salt concentration, thickness, and elastic modulus of substrate on tip deflections are also discussed in this paper. These factors can significantly affect the deflections of the biosensor. This work demonstrates that it is useful to develop a theoretical model for the label-free nanomechanical detection technique.

Large Deflection of a Cantilever Nanobeam under a Vertical End Load

2013 ◽  
Vol 353-356 ◽  
pp. 3387-3390 ◽  
Author(s):  
Ming Chen
Keyword(s):  
Molecular Dynamics ◽  
Time Scales ◽  
Governing Equation ◽  
Large Deflection ◽  
Bending Moment ◽  
Shearing Force ◽  
Concentrated Load

Large deflection of a cantilever nanobeam subjected to a tip-concentrated load whose verticality to the deformed axis of the beam is assumed as constant. Governing equation is analyzed by using the shearing force formulation instead of the bending moment formulation because in the case of large deflection member, the shearing force formulation possesses some computational advantages over the bending moment formulation. The condition of boundary is discussed by several ways. The different sizes of loads and time scales are used to analyze the deformation and the different by molecular dynamics.

scholarly journals Dynamic Characteristics of Microring Driven by the Symmetrically Distributed Electrostatic Force

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Qingheng Meng ◽  
Yuanlin Zhang ◽  
Jin Wei ◽  
Yuh-Chung Hu ◽  
Yan Shi ◽  
...  
Keyword(s):  
Governing Equation ◽  
Dynamic Characteristics ◽  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Electrostatic Force ◽  
Damping Ratio ◽  
Nonlinear Partial Differential Equation ◽  
Great Influence ◽  
Taylor Series Expansion ◽  
Forced Response

This paper aims at investigating the dynamic characteristics of a microring driven by dual arch electrodes because they are basic elements of microelectrostatic motors. The dual arch electrodes surround the periphery of the microring and are arranged symmetrically to the center of the ring. The electrodes are fixed while the microring is flexible. The electrostatic force will deform the microring, while the deflection of the microring changes the gap between the microring and the electrodes, thereby changing the electrostatic force. Therefore, this is an electromechanical coupling effect. The nonlinear partial-differential equation that governs the motion of the microring is derived based on thin shell theory. Then, based on the assumption of small deflection, the nonlinear governing equation is linearized by truncating the higher-order terms of the Taylor series expansion of the nonlinear electrostatic force. After that, the linearized governing equation is discretized into a set of ordinary differential equations using Galerkin method in which the mode shape functions of the ring are adopted. The influences of the structural damping of the microring and the span of the arch electrodes on the forced response and dynamical stabilities of the microring are investigated. The results show that the damping ratio has a great influence on the system instability during high-frequency excitation. The unstable region of the system can increase with the increase of the electrode span; the response amplitude can also be increased within a certain range.

Phase separation in sol gel-derived ceramic films of silica-zirconia, alumina-zirconia, and titania-zirconia system

1994 ◽  
Vol 52 ◽  
pp. 646-647
Author(s):  
J. Tong ◽  
L. Eyring
Keyword(s):  
Fracture Toughness ◽  
Phase Separation ◽  
Sol Gel ◽  
Great Influence ◽  
High Strength ◽  
Chemical Durability ◽  
Separation Method ◽  
Toughening Mechanism ◽  
Ceramic Films ◽  
Zirconia Toughened Alumina

There is increasing interest in composites containing zirconia because of their high strength, fracture toughness, and its great influence on the chemical durability in glass. For the zirconia-silica system, monolithic glasses, fibers and coatings have been obtained. There is currently a great interest in designing zirconia-toughened alumina including exploration of the processing methods and the toughening mechanism.The possibility of forming nanocrystal composites by a phase separation method has been investigated in three systems: zirconia-alumina, zirconia-silica and zirconia-titania using HREM. The morphological observations initially suggest that the formation of nanocrystal composites by a phase separation method is possible in the zirconia-alumina and zirconia-silica systems, but impossible in the zirconia-titania system. The separation-produced grain size in silica-zirconia system is around 5 nm and is more uniform than that in the alumina-zirconia system in which the sizes of the small polyhedron grains are around 10 nm. In the titania-zirconia system, there is no obvious separation as was observed in die alumina-zirconia and silica-zirconia system.

Perceptions of Qualities of Life: Duration Neglect and the Peak-and- End Effect

1999 ◽  
Author(s):  
Derrick Wirtz ◽  
Ed Diener ◽  
Lonnie Brewer ◽  
Shige Oishi
Keyword(s):  
End Effect ◽  
Life Duration ◽  
Duration Neglect

Optical imaging probes and their potential contribution to radiotracer development

2016 ◽  
Vol 55 (02) ◽  
pp. 51-62 ◽  
Author(s):  
S. Hermann ◽  
M. Schäfers ◽  
C. Höltke ◽  
A. Faust
Keyword(s):  
Optical Imaging ◽  
Fluorescent Dyes ◽  
Great Influence ◽  
Potential Contribution ◽  
Preclinical Evaluation ◽  
Guided Surgery ◽  
Fluorescence Guided Surgery ◽  
Imaging Probes ◽  
Unspecific Binding

SummaryOptical imaging has long been considered a method for histological or microscopic investigations. Over the last 15 years, however, this method was applied for preclinical molecular imaging and, just recently, was also able to show its principal potential for clinical applications (e.g. fluorescence-guided surgery). Reviewing the development and preclinical evaluation of new fluorescent dyes and target-specific dye conjugates, these often show characteristic patterns of their routes of excretion and biodistribution, which could also be interesting for the development and optimization of radiopharmaceuticals. Especially ionic charges show a great influence on biodistribution and netcharge and charge-distribution on a conjugate often determines unspecific binding or background signals in liver, kidney or intestine, and other organs.Learning from fluorescent probe behaviour in vivo and translating this knowledge to radio-pharmaceuticals might be useful to further optimize emerging and existing radiopharmaceuticals with respect to their biodistribution and thereby availability for binding to their targets.

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