Nano void

Keywords fullerenes, nano void, positronium, liquid crystal, lanthanum laurate... 

Positronium (Ps) annihilation probability in the nanovoids of the samples in initial state is found to be 11.13 %, whereas the mean nano void radii for the crystalline and liquid-crystalline samples are 0.33 and 0.28 nm, respectively. After dissolution of C6o fullerenes probability of Ps annihilation in nanovoids is decreased by the factor of 2.7. The general spectrum of lanthanum laurate initial pattern is presented in the Fig. 1. The calculated parameters of the investigated patterns are resulted in the Table 1. 

Figure 2. Intensity dependence of narrow ACAP spectra s component (SN) from nano void radius (R) for first fraction of tri-glucerids in crystalline state at 22 0C ( ) and 36 0C, the sixth fraction of tri-glucerids in liquid state (A), the mix of first and sixth fractions at 25 0C (A) for two patterns La(Cl2H25COO)3 ( ) and with fullerens ( ) at 22 0C.

In the present paper we demonstrate the formation of an array of precisely self-adjusted nano-voids. The nano-voids are obtained as a result of implantation of Ge ions followed by a thermal treatment. The means of self-ordering of the voids utilizes t he strain s ituation a round t hin S iGe 1 ayers (quantum wells) i ncorporated into a thick Si layer [5]. Due to compressive strain, SiGe/Si layers may effectively getter and accumulate vacancies and vacancy-related defects, which transform into nanovoids during subsequent thermal treatment. 

Zhurkov et al. (1969) studied the nature of the molecular-level fracture processes in Nylon-6 (polycaprolactam) in detail by small-angle X-ray scattering (SAXS) at 300 K in a material having the same level of molecular orientations of 1 = 4.5 for a range of applied stresses of 200 250 MPa. This establishes that rapid fracture at these stress levels involves an increase of a concentration N of nano-voids of a diameter in the range 100-200 mn, increasing at a rate that is exponential in the stress and given by... 

To relate these observations to an actual crack-extension process in a sample of similar microstructural pedigree, Zhurkov et al. (1969) carried out an experiment in a sample containing a notch as shown in Fig. 12.22 and monitored the initiation of fracture, starting from the notch. They noted, as expected, that fracture is initiated when the nano-void concentration at the notch tip reaches the critical level of 5 x 10 m . ... 

Fig. 12.22 Propagation of a crack in oriented Nylon film starting from an edge notch when the notch-tip nano-void concentration reaches a critical level (from Zhurkov et al. (1969) courtesy of Chapman and Hall).

In the SAXS analysis, the flame-like shape is obtained due to the scattering pattern obtained from nanovoids and butterfly shape is originated from scattering of fillers. Nano voids are initiated at a small strain range and grow perpendicular to the stretching direction as the strain attained a higher value. ... 

Fig. 17.24 TEM micrographs of nylon 6/organoclay/EOR-g-MA (76/4/20) ternary nanocomposite showing (a) submicron and nano-voids which are associated with intra-gallery delamination of some organoclay layers (note that the section is not selectively stained in order to clearly reveal delaminations of clay layers), (b) cavitation of EOR-g-MA particles which preferentially starts from the larger particles as indicated by arrows, and (c) extensive matrix shear yielding at the arrested crack tip which in turn causes the EOR-g-MA particles and delaminated clay layers to collapse within the matrix. A schematic of the arrested crack tip illustrating different locations from where TEM micrographs (a-c) were taken is also shown. Note that the schematic is not to scale (Lim et al. 2010)...

More precisely, the scattering invariant for an ideal binary phase system without nano-voids is expressed by Eq. (11.10) (Glatter and Kratky 1982) ... 

Electrochemical deposition of metal followed by removal of PS mask leaves nanostmetured film containing a regular hexagonal array of metallic nanoislands, nanoholes or nano voids depending on the thickness of the deposited film (Abdelsalam et al. 2005). 

Mitulovic, G., Smolnch, M., Chervet, J. R, Steinmacher, I., Kungl, A., and Mechtler, K., An improved method for tracking and redncing the void volnme in nano HPLC-MS with micro trapping columns. Analytical and Bioanalytical Chemistry 376(7), 946-951, 2003. 

Ultrathin oxide gel films prepared by the surface sol-gel process include many nano-sized voids, and the film density is generally low. Their compositions and... 

An improved method for tracking and reducing the void volume in nano H PLC-M S with micro trapping columns. Anal. Bioanal. Chem. 376, 946-951. 

As experimental techniques for measuring displacement and strain become increasingly accurate at micro- and nano- length scales, experiments must be performed to verify the accuracy of predictions of models of material behavior at these scales. In particular, the use of diffraction techniques for measurements of lattice distortion [20] combined with surface measurement techniques such as micro-Moire [21], speckle interferometry [22] and displacement mapping [23] promise to provide essential information on the local deformation behavior of metals and alloys in the vicinity of grain boundaries, voids and second phase particles. These techniques must be further developed and applied to the analysis of real materials to increase our knowledge of material behavior at these length scales. 

It has been menhoned before (Section 4.2.1) that apart from the spherical carbon onions, there are also markedly faceted structures. Some of these exhibit a large central cavity (Figure 4.7a). They may be generated, for instance, by heating spherical nano-onions, or by direct methods like arc discharge or others. Structures of this kind are furthermore observed as faceted shells of metal nanoparticles that fill the void within the carbon structure. 

An analysis of the calculated unit cell dimensions during desorption shows the lattice contracts as ammonia is removed. Since the macroscopic shape is retained, this is possible only if voids or a porosity develops simultaneously. In a macroscopic system, the salt is polycrystalline and the desorption process can be followed using, e.g. small-angle X-ray scattering (SAXS), which reveals the gradual formation of a skeletal structure (Fig. 19.9b) and the ultimate creation of an intrinsic nano-scale porosity in the MgCl2 crystallites... 

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