Veng Cheong Lo

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First-principles calculations were performed to study the structural, elastic, and electronic properties of the crystalline form of C(20), C(12)B(8), and C(12)N(8). These compounds exhibit very different elastic and electronic properties. The shear modulus of C(12)N(8) is much higher than those of C(20) and C(12)B(8). The strong covalent C-N interaction(More)
The vibration displacement distributions along a transducer used in ultrasonic wire bonding were measured using a heterodyne interferometer, and many nodes and anti-nodes were found. A mechanical finite element method (FEM) was used to compute the resonant frequencies and vibration mode shapes. The displacement distributions of the dominant 2nd axial mode(More)
First-principles calculations were carried out on recently synthesized Re₂N and Re₃N as well as hypothetical Tc and Mn nitrides. It is found that structure and covalent bonds play an important role in determining mechanical properties. Under a large strain along (0001)<1010> direction, Re₂N undergoes a phase transformation with a slight increase in ideal(More)
Experimental results on electromechanical properties of lead zirconate titanate ceramic sample under combined alternating mechanical and mechanical loadings as manifested by the strain -electric field, and electric displacement -electric field relations have been numerically simulated using four-state Potts model. The dipole from each of the perovskite(More)
The roles of space charge induced in the ferroelectric thin film and the presence of Schottky barriers at the two electrode/film interfaces are studied by numerical simulation using Landau-Khalatnikov theory. In this work, the whole film is considered as the stacking of dipolar layers, each of which contains multilayers of perovskite cells. In the presence(More)
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