Abstract: A special kind of surface modified copper nanoparticles was selected as the
auto-reconditioning materials to in situ generate a copperized protective film on iron-base metal
surfaces under designed tribological conditions. The morphologies and element distributions of the
formed film were observed and determined by scanning electron microscopy (SEM) and energy
dispersive spectrometry (EDS). The micro mechanical properties and tribological behaviors were
investigated by nano test system and ball-on-disc tribotester. The results show that the morphology
of the protective film is smooth, the nano-hardness decreases by 46% and the friction coefficient of
the copperized protective film is about 0.10. The forming mechanism of the auto-reconditioning
film can be described that the copper nanoparticles deposit on the worn surfaces and form
iron-copper alloy film with lower hardness and shear strength, which has better friction-reducing,
antiwear and surface-optimizing behaviors.
Abstract: A three dimensional molecular dynamics model is employed to simulate AFM-based
lithography process. To investigate effects of tip geometry, three kinds of tip models are proposed:
a cone-shape tip with a hemisphere at the end, a round-edged three sided pyramid tip with a
hemisphere at the end and a sharp-edged three sided pyramid tip. These models simulate scratching
behaviors of AFM tip at different scratching depths. Results showed that materials removal
behavior and scratching forces were significantly affected by tip geometry, depending on the
scratching depth and scratching directions. The specific energy using a sharp-edged three sided
pyramid tip displayed a different behavior comparing to that using a round-edged three sided
pyramid. However, scratching orientations exhibited no effects on the specific energy.
Abstract: This paper introduces a fluidic technique based on patterned shapes of hydrophobic
self-assembly monolayers (SAMs) and capillary forces to self-assemble micro-parts onto substrates.
Self-assembly is defined as a spontaneous process that occurs in a statistical, non-guided fashion.
More specifically, the fluidic self-assembly with capillary force is driven by the gradient in
interfacial free energy when a micro-part approaches a substrate binding site. In this paper, the
mechanism of self-assembly with capillary forces is proposed. The hydrophobic-hydrophilic
material system between the binding sites and micro-parts is then simulated. Finally, the surface
energy of a self-assembling system in the liquid phase under different conditions is calculated. The
results show that shift, twist, lift and tilts displacements are detected to be rather uncritical and the
system turns out to be rather stiff with respect to such displacements. The theoretical result is
supported by the experiments and gives quantitive explanations why and how the capillary force
works in the self-assembly process.
Abstract: This paper aims to make piezoelectric ceramic actuator self-sense its own displacement
in the absence of independent sensor. It is derived from the basic piezoelectric equation that the free
charge on the wafer of piezoelectric ceramic actuator contains displacement information. So a
displacement self-sensing method based on integrate circuit is presented. Voltage driving circuit for
the piezoelectric ceramic actuator and integrated circuit for gathering free charge are designed.
Based on the proposed compound circuits, the actuator can sense its own displacement while
actuation. It is convenient to adjust the circuit and easy to acquire sensitive signal by using this
method, and the impedance mismatching problem met in bridge method is overcome. The
experimental results show that piezoelectric self-sensing actuator can effectively measure its
displacement signal under the conditions of different wave form of driving voltage and different
driving voltage frequency.
Abstract: Micro hot embossing mold of microfluidic chip used in flow cytometry is designed and
microfabricated. After some kinds of microfabrication processes are tried, this paper presents a
novel microfabrication technology of micro hot embossing metal mold. Micro metal mold is
fabricated by low-cost UV-LIGA surface micro fabrication process using negative thick photoresist,
SU-8. Different from other micro hot embossing molds, the micro mold with vertical sidewalls is
fabricated by micro nickel electroforming directly on Nickel base. Based on the micro Nickel mold
and automation fabrication system, high precision and mass-producing microfluidic chips have been
fabricated and they have been used in flow cytometry
Abstract: In this paper, nonequilibrim molecular dynamics (NEMD) was used to simulate liquid
flow in microchannels with ‘lotus effect’ coating. Without considering atomic structure and
long-range interaction, we have been dedicated in establishing a two-dimensional geometric model
based on the coating and studying the behavior of liquid near the inner surfaces of ‘lotus effect’
microchannels. The shape of a single pattern in the coating and the thickness of one microchannel
were varied to study the influences of these parameters on velocity profile of liquid in the flow
direction, the maximum of this velocity, and its position perpendicular to flow direction. The proper
conditions which made the velocity slip of liquid near the boundary layer of microchannels
maximum and liquid move most fast were decided.
Abstract: An assembly bed on thermosonic flip chip bonding was set up, two different structures of
tool tips were designed, and a series of experiments on flip chip and bonding machine variables
were carried out. Lift-off characteristics of thermosonic flip chip were investigated by using
Scanning Electron Microscope (JSM-6360LV), and vibration features of tool tips driven by high
frequency were tested by using PSV-400-M2 Laser Doppler Vibrometer. Results show that, for
chip-press model, slippage and rotation phenomena between tool tip and chip have been solved by
using tool with greater area tip pattern during flip-chip bonding process, and welding failures
appeared in chip-collet model have been controlled. Greater area pattern on tool tip is better than
small area pattern. The power of ‘n’ bumps on flip chip bonding is far smaller than that of n×(the
power of single wire bonding). The power is directly proportion to vibration displacement driven by
the power, high-power decrease positioning precision of flip chip bonding or result in slippage and
rotation phenomena. The proper machine variables ranges for thermosonic flip chip had been
Abstract: This paper deals with a novel polishing technology using polymer particles. It has been
proposed and developed by the authors for the purpose of solving the problems associated with
polishing pads such as pad deterioration, process inconsistency and poor accuracy. Single side
polishing of silicon wafers and double side polishing of quartz crystal square wafers were
performed to clarify the basic characteristics of the technology. The results showed that appropriate
combination of tool plate with polymer particles could greatly improve polishing characteristics.
In particular, the edge profiles can be controlled to have desirable shape as well as amplitudes.
Abstract: For the problem of process monitoring of chip generation in CNC machining, the
dynamic modeling of predicting chip formation using artificial neural networks based on real-time
condition intelligent monitoring was studied. The dynamic model of predicting chip formation is
established in this paper. Based on mathematical model of chip space motion path, the 3D model of
chip shape was developed. The real-time simulation of chip generation was realized in the virtual
Abstract: Bifurcation of multi-layer microstructures subjected to thermal loading can be harmful
for reliability and stability of MEMS structures. In this paper, three imperfections of geometry,
coefficient of thermal expansion and thermal loading were introduced to investigate their effects on
structural bifurcation by finite element simulation. Results show that bifurcation is strongly
influenced by the imperfections. With larger deviation of imperfections, it results in a decreasing
temperature to trigger the bifurcation and a gradual beginning of it.