Sổ tay ma sát và Nano P11 pot

... indentation to approximately the same value of maximum force was repeated, plastic deformation was also observed. However, the atomic-scale details, including the degree of damage, differed. The ... constants, the curvature and magnitude of potential wells, and bulk phonon frequencies. The main drawback of these approaches is that simplifying assump- tions must be made as part of these models...

Ngày tải lên: 04/07/2014, 07:20

... G.M., 1992, J. Mater. Res. 7, 1564–1583. With permission.) FIGURE 10.21 Schematic of load–displacement curve. hh W S c =− max max max ε hh W S p =− max max max © 1999 by CRC Press LLC remains unchanged. ... 90° may be desirable for a more durable tip. The tip radius should not be very small as it will get blunt readily. FIGURE 10.17 (a) Schematic of nanoindenter with an AE transducer, (b) sch...

Ngày tải lên: 04/07/2014, 07:20

... surface micromachining. In contrast to substrate micromachining in which mechan- ical parts are sculpted from the wafer itself, surface micromachining makes mechanical elements out of materials ... the motions of very small bodies in which micrograms are proper units of mass. At this scale, as we know from observing the insect world, inertial effects play far smaller (in many cases negligible...

Ngày tải lên: 04/07/2014, 07:20

... strengths of the corresponding bulk materials. Many theories to explain these stresses have been suggested, and a summary is given in a review by Windischmann (1992). Intrinsic tensional stresses ... instead prefer to form small, particle-like precipitates, resulting in a maintained low yield limit, see Figure 15.5. Also, during plastic deformation these precipitates may act as sources for .....

Ngày tải lên: 04/07/2014, 07:20

... properties of mating components dominate the tribological perfor- mance. In micro/nanotribology, measurements are made on components, at least one of the mating components, with relatively small mass ... 1989; Mamin et al., 1990; Utsugi, 1990; Hosoki et al., 1992; Kobayashi et al., 1993), and nanomachining (Parkinson, 1990). AFMs have also been used for nanofabrication (Maju...

Ngày tải lên: 04/07/2014, 07:20

... the mass to 0.1 µg. This lumped mass m eff , however, is smaller than the real mass m, by a factor that depends on the geometry of the cantilever. A good rule of thumb says that the effective mass ... the real mass. Today, micro-machined cantilevers are commercially available and are used almost exclusively. 2.2.4 Materials and Geometry Cantilevers have been made from a whole range of materia...

Ngày tải lên: 04/07/2014, 07:20

... elastic effects in any measuring apparatus and in the materials involved that make measurement of the force distribution at the interface difficult. Materials can change mechanical properties as a result ... as hardness, ductility, defect formation, plasticity, strain hardening, and creep must be considered. Surface properties may be altered just by contact with the counterface material (Carpi...

Ngày tải lên: 04/07/2014, 07:20

... be resolved. One may ask how is it that, under increasing load, smaller asperities under plastic deformation may merge to form a larger spot which can be under elastic deformation. A qualitative answer ... of elastic contact area increases. This results from merging of small contact spots in plastic deformation to form larger spots in elastic deformation. The effects of fractal dimension on t...

Ngày tải lên: 04/07/2014, 07:20

... water (≈80). 5.3.4 Electromagnetic Forces There are three classes of magnetism — diamagnetism, paramagnetism, and ferromagnetism. In paramag- netic and diamagnetic materials, electron spins are ... was written. For example, many simulations neglect the fact that electrons have spin, so that normally magnetic materials may not have magnetic moments in a simulation. Magnetic forces can overpowe...

Ngày tải lên: 04/07/2014, 07:20

... be deflected (normal force signal). Images taken in the constant-height mode show no contrast in the topographic image, in this case all information is in the normal force image. Images taken in ... constant-force mode, topographic image is obtained by adjusting the position of the sample to maintain a constant force. Hence, minima and maxima of the normal force and of the topography coincide...

Ngày tải lên: 04/07/2014, 07:20