Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On modeling and measuring viscoelasticity with dynamic Atomic Force
  Microscopy   The interaction between a rapidly oscillating atomic force microscope tip and
a soft material surface is described using both elastic and viscous forces with
a moving surface model. We derive the simplest form of this model, motivating
it as a way to capture the impact dynamics of the tip and sample with an
interaction consisting of two components: interfacial or surface force, and
bulk or volumetric force. Analytic solutions to the piece-wise linear model
identify characteristic time constants, providing a physical explanation of the
hysteresis observed in the measured dynamic force quadrature curves. Numerical
simulation is used to fit the model to experimental data and excellent
agreement is found with a variety of different samples. The model parameters
form a dimensionless impact-rheology factor, giving a quantitative physical
number to characterize a viscoelastic surface that does not depend on the tip
shape or cantilever frequency.

17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
29
The categories of this paper are: funct-an
35
The categories of this paper are: mtrl-th