Sliding Distance Research Articles

Effect of load on tribological behaviour of carbon-carbon composites

The effect of load on the tribological behaviour of three different two-dimensional carbon-carbon composites, including polyacrylonitrile (PAN) fibre-pitch matrix, PAN fibre-chemical vapour infiltrated (CVI) matrix, and pitch fibre-resin/CVI hybrid matrix composites has been compared. Results indicated that friction and wear rate variations with slide distance depended on load and the type of composite. The worn surface morphology was categorized into three types (I, II and III). The friction coefficient, wear rate and temperature all increased sharply when the transition from type I to type II occurred. When the powdery type II debris was compacted to form the lubricative type III debris, the friction coefficient and wear rate declined, although never approached their initial type I levels. For all composites, a higher load can accelerate the transition from type I to type II, but impedes the transition from type II to type III. Under 2.4 MPa, the type II morphology was never observed to transform into type III morphology in this study.

Muscle Contraction Simulation based on Molecular Potential Theory. Sliding Motion of Myosin.

In this paper, a numerical method for analysing muscle contraction has been derived based on the modified Mitsui's self-induced translation model. Discussion is focused on a molecular potential distributed along the actin and myosin filaments. Three potentials are introduced: the periodic potential along the actin filament, the self-induced potential on myosin heads and the elastic potential of heavy meromyosin rods. The energy of ATPase generates the self-induced potential between myosin and actin filaments, and forces the myosin to slide along the actin filament. The isotonic contraction is simulated. Numerical results of myosin motion show good agreement with recent experimental results of myosin slide distance from l0 nm to 200 nm in vitro motility assay.

Effects of interfacial microstructure on uniformity and thermal stability of AuNiGe ohmic contact to n-type GaAs

As part of the investigation of the use of AuNiGe as the ohmic contact to n-type GaAs at a high integration level, cross-sectional transmission electron microscopy was used to explore the uniformity at the metal/GaAs interface and the thermal stability of the AuNiGe contact after the ohmic contact formation. A close relation between spread of the contact resistance and nonuniformity of the interfacial microstructure of the contact was found. Deposition of 5-nm-thick Ni as the first layer of the AuNiGe ohmic contact significantly reduced the spread of the contact resistance and led to the formation of a uniform interface without large protrusions. The improvement in uniformity of compound distribution and the reduction of interface roughness are believed to be due to a change in the sequence of alloying reactions, compared to those in the contact without a Ni first layer. This suggests an ideal interface structure for a low resistance AuNiGe ohmic contact after alloying to be a uniform two layer structure: a high density of the NiAs(Ge) grains contacting the GaAs substrate, and a homogeneous β-AuGa phase close to the top surface. However, due to the existence of β-AuGa phases with a low melting point of around 375 °C, the thermal stability of the contact at 400 °C is of serious concern. Segregation of the NiAs(Ge) grains was observed after annealing at 400 °C for 10 h, which reduced the contact areas between the NiAs(Ge) grains and GaAs. During subsequent annealing at this temperature for up to 90 h, liquidlike flow of the β-AuGa phase was observed which deteriorated the interface uniformity, causing an increase in contact resistance. A typical contact edge slide distance after contact alloying at 440 °C for 2 min was measured to be 0.2 μm and the longest distance among specimens examined was 0.47 μm. This edge deterioration could limit the use of the AuNiGe contact in GaAs submicron devices.

Effect of Normal Stiffness in Loading System on Wear of Carbon Steel—Part 2: Dynamic Normal Load and Effective Sliding Distance

In order to explain the effect of normal stiffness in the loading system on wear, the mean dynamic normal load and the effective sliding distance were determined from the record of dynamic normal load. The mean dynamic normal load was approximately constant at normal stiffnesses smaller than 10 N/mm and increased markedly at normal stiffnesses larger than 103 N/mm. The effective sliding distance was approximately equal to the apparent sliding distance at normal stiffnesses smaller than 10 N/mm and decreased markedly at normal stiffnesses larger than 103 N/mm. The effective wear rate was newly defined in terms of the effective sliding distance. The change of effective wear rate with the change of sliding velocity was linearly correlated to the change of mean dynamic normal load under each normal load and normal stiffness.

Stability of Mixed-Type Breakwater: A Method of “Probable Sliding Distance”

SYNOPSISThis paper deals with the stability of vertical walls in mixed type breakwaters. A new concept named “probable sliding distance” is presented to evaluate the stability of caisson walls under the action of irregular waves.The fundamental idea of probable sliding distance lies in the examination of the behaviour of structures beyond the stability limit for evaluating their ultimate safety. The frequencies and the amounts of the displacement of model caissons mounted on rubble mounds were observed in an irregular wave basin. The intensity of wave pressure and the coefficient for calculating the sliding distance have been obtained from these experiments.The “probable sliding distance” is defined as an expected total displacement of a caisson due to irregular waves of a certain magnitude and duration. The conventional design standard is examined on the basis of this idea and a revision of stability calculation is proposed.