Juan Ren

US Patent:

20130347147, Dec 26, 2013

Filed:

Jun 24, 2013

Appl. No.:

13/925441

Inventors:

Qingze Zou - Bridgewater NJ, US
Juan Ren - Highland Park NJ, US

International Classification:

G01Q 60/38

US Classification:

850 40

Abstract:

A control-based approach is provided for achieving accurate indentation quantification in broadband and in-liquid nanomechanical property measurements using atomic force microscope (AFM). Accurate indentation measurement is desirable for probe-based material property characterization because the force applied and the indentation generated are the fundamental physical variables that are measured in the characterization process. Large measurement errors, however, occur when the measurement frequency range becomes large (i.e., broadband), or the indentation is measured in liquid on soft materials. Such large measurement errors are generated due to the inability of the conventional method to account for the convolution of the instrument dynamics with the viscoelastic response of the soft sample when the measurement frequency becomes large, and the random-like thermal drift and the distributive hydrodynamic force effects when measuring the indentation in liquid.

US Patent:

20170199219, Jul 13, 2017

Filed:

Jul 14, 2015

Appl. No.:

15/326237

Inventors:

- New Brunswick NJ, US
Juan Ren - Edison NJ, US
Jiangbo Liu - Piscataway NJ, US

Assignee:

Rutgers, The State University of New Jersey - New Brunswick NJ

International Classification:

G01Q 10/06
G01Q 60/34

Abstract:

A method for imaging a sample using a high speed dynamic mode atomic force microscope may include scanning a tip of a cantilever probe over a surface of the sample, regulating a vibration amplitude of the tip to remain constant at a set point value (A), via a first signal generated in a first feedback controller, measuring a mean tapping deflection of the tip, regulating the mean tapping deflection via a second signal generated in a second feedback controller, tracking and measuring an adjustment to the measured mean tapping deflection during the regulating. The method may further include generating an image topography of the sample based on the first signal, the second signal, and the measured adjustment of the mean tapping deflection of the cantilever probe.