Abstract: As silicon ICs continue to scale down, several reliability issues have emerged.
Electromigration- the transportation of metallic atoms by the electron wind- has been recognized as
one of the key damage mechanisms in metallic interconnects. It is known that there is a threshold
current density of electromigration damage in via-connected lines. The evaluation of the threshold
current density is a matter of the great interest from the viewpoint of IC reliability. In this study, Al
polycrystalline lines with two-dimensional shape, i.e. angled lines are experimentally treated for the
evaluation. Comparing the experimental result with that of straight-shaped line, the effect of
line-shape on the threshold current density of electromigration damage is discussed.
Abstract: This paper studies the crack propagation at Sn37Pb-copper interface in push-pull low
cycle fatigue. Bonded specimens of Sn37Pb and copper having notch holes with different distances
from the interface were fatigued at 313K and the crack propagation paths were observed. Cracks
propagated at the interface when the notch hole was near the interface but propagated in the solder
when the notch hole was away from the interface. The propagation rate of the interfacial crack was
faster than that of non-interface crack. The crack path and crack propagation rate of the two types
of cracks were discussed in relation to J integral range calculated by finite element method.
Abstract: ZnO is an n-type semiconductor having a hexagonal wurzite structure. ZnO exhibits good
piezoelectric and optical properties, and might be a good candidate for an electroluminescence device
like an UV laser diode. Then, these devices are very small, their films are very thin and they are
prepared in the limited size and shape, so they are unsuitable for the extensive mechanical testing. In
this present work, ZnO thin films are prepared on the glass, GaAs(100), Si(100) and Si(111)
substrates at various temperatures by the pulsed laser deposition (PLD) method. ZnO thin films were
evaluated by X-ray diffraction (XRD) and mechanical properties such as hardness and elastic
modulus were measured through the nano-indenter.
Abstract: This study is to present a numerical investigation on fragmentation and perforation of
concrete slab by hard projectile using discrete particle approaches. Discrete Element Method (DEM)
and Discontinuous Deformation Analysis (DDA), the two representative discrete particle approaches,
are employed to simulate a normal perforation of concrete slab by a hard ogival-nose shaped
projectile, and the phenomena of spalling, plugging and scabbing are reproduced.
Abstract: In this paper, the fractal characterization of the sealing surface topography of metallic
gaskets was studied. The influence of the compressive stress on the fractal parameters was also
investigated. It’s found that the sealing surface of metallic gaskets is fractal, and its topography can
be characterized by the fractal dimension and the scale coefficient. The leakage model of metallic
gaskets was established. The research results indicate that the larger the fractal dimension is, and
the less the scale coefficient and the non-contact area are, the better the sealing performance of
metallic gaskets is.
Abstract: Al-Ti-C grain refiners have been prepared by combining self-propagating
high-temperature synthesis (SHS) technique and melting-casting method. Effects of Al powder size
and C/Ti ratio on the microstructures and grain-refining efficiency of Al-Ti-C grain refiners were
studied by OM, XRD, SEM and EDS. The results show that when Al powder size is fine, and C/Ti
ratio is 1: 8, SHS reaction among the mixed powders can easily carry on in the melt. As a result,
the prepared grain refiner consists of blocky Al3Ti and fine TiC particles distributed in Al matrix,
and exhibits excellent grain refining performance on commercially pure Al.
Abstract: The cooling medium choice is restricted due to no detailed regulations for temperature
control as the specimen with gaseous cooling medium in the API, ASTM and the standards or
specifications of China. The analysis and calculating are made to the physical process of the
cooling. The preservation hold time are provided for DWTT specimen at different temperature in
the gaseous cooling medium. It provide primary sustaining base to control the cooling process of
gaseous cooling medium. The essential point of the precise means of temperature testing is brought
forward at the same time.
Abstract: While the fact that abrasion leads to change of surface topography is taken into
consideration, the influence of spring pressure both on leakage rate and on friction characteristic of
contacting mechanical seals are investigated by fractal theory. Several GY-70 type mechanical seals
are tested. Both theoretic analysis and test results indicate that the friction will be more serious
because lubrication medium between two end faces reduces as spring pressure increases, though the
increase of the spring pressure may not be enough to change the face friction state of mechanical
seal. There is an optimum spring pressure for mechanical seal operation. Under different operating
conditions, identical type mechanical seals may possess different spring pressure. Appropriate
selection of spring pressure is key to the mechanical seal operation under the best condition.
Abstract: The twin shear strength criterion has been proposed to consider the intermediate principal
stress effect on the rock mass strength. The unified rock mass strength criterion could consider the
intermediate principal stress effect on the rock mass strength. The unified rock mass elasto-plastic
material model is implemented in ABAQUS user interface. As a case for study, the stability
analysis of Dongjusi railway tunnel within hard rock mass is studied using the unified rock mass
strength material. For comparison, the Hoek-Brown empirical strength criterion is also chosen for
the rock mass material modeling. The computation results show that the plastic zone calculated
using the unified rock mass strength criterion is smaller than that using the Hoek-Brown empirical
strength criterion. The railway tunnel lining structure is designed according to the unified rock mass
strength criterion and greatly makes use of the rock mass potential strength, which decreases
Abstract: Large numbers of experimental results show that carbides Me3C (Me means Fe, Ni, Co,
Mn) are the primary carbon source to form diamond structure under the high temperature and high
pressure (HPHT). In this paper, based on the empirical electron theory of solids and molecules (EET),
the valence electron structure (VES) and interface structure factors of diamond and various carbides
are calculated, and the boundary condition of electron movement in the improved Thomas-
Fermi-Dirac theory by Cheng (TFDC) is applied to the carbide/diamond interfaces. It is found that the
electron density of crystal plane in Me3C formed by C-C bonds is continuous with that in diamond at
the first order of approximation. Compared with Ni-based carbides [Ni3C, (NiMn)3C)], the electron
density difference of Fe-based carbides [Fe3C, (FeNi)3C, (FeMn)3C]/diamond interfaces is lower, and
that of (FeNi)3C/diamond interface is minimum. The results show that the energy needed to transform
carbon atomic groups into diamond structure is lower for Fe-based carbides than Ni-based carbides.