Nano-particle

Saxena A., Sachin K, Bohidar H.B., Verma A.K. 2005. Effect of molecular weight heterogeneity on drug encapsulation efficiency of gelatin nano-particles. Colloids and Surfaces B Biointerfaces 45,42-48. 

The research presented in Section 6.1 on two phase flow containing nano-particles was carried out using the Fluo-rometiy Technique developed recently in Professor Luo s group. 

The solid-liquid two-phase flow is widely applied in modern industry, such as chemical-mechanical polish (CMP), chemical engineering, medical engineering, bioengineering, and so on [80,81]. Many research works have been made focusing on the heat transfer or transportation of particles in the micro scale [82-88], In many applications, e.g., in CMP process of computer chips and computer hard disk, the size of solid particles in the two-phase flow becomes down to tens of nanometres from the micrometer scale, and a study on two-phase flow containing nano-particles is a new area apart from the classic hydrodynamics and traditional two-phase flow research. In such an area, the forces between particles and liquid are in micro or even to nano-Newton scale, which is far away from that in the traditional solid-liquid two-phase flow. 

For most existing measuring methods, the actual motion of individual nano-particles in two-phase flow cannot be observed easily. Conventional particle image velocimetry (PIV) apparatus can measure the particles in micro scale... 

These spherical nano-particles about 55 nm in diameter have a fluorescent material of ruthenium pyridine inside, and the shell of silicon dioxide, as shown in Fig. 36. The excitation wavelength of the ruthenium pyridine is 480 nm and the emission wavelength is 592 nm [81]. In order to get a clear image of nano-particles, the mass concentration of the fluorescent particles should be limited to a very low level. 

Fig. 36—Photograph of nano-particles, (a) SEM photograph, (b) photograph under fluorescence microscope.

Therefore, the samples are prepared by mixing fluorescent particles solution and silicon dioxide nano-particles solution as shown in Table 1. 

Characteristics of Two-Phase Flow Containing Nano-particles—A Study by the Present Authors... 

From the image sequences, information on the velocities of nano-particles can be extracted. The statistical effect of Brownian motion on the flowing speed of the mixed liquid is found small enough to be ignored as shown in Fig. 37 where most of the particles trajectories in the liquid are straight lines and parallel with the wall basically. Therefore, Brownian diffusive motion is ignorable. 

Therefore, the velocities of liquid are consistent with the velocities of particles, that is, the motion of nano-particles can reflect the flow of liquid verily in the given condition. Figures 39 and 40 show the comparison of the two liquid samples with different mass concentration of the nanoparticles at different flow rates. Generally, particle velocity increases synchronously with the liquid flow rate, but the velocity becomes dispersive when it exceeds 300 /u,L/min. The more the particles were added in the liquid, the more dispersive of the velocities of the particles were observed. Several possible causes can result in this phenomenon. One possible reason is that when the velocity of flow becomes large enough, the bigger particles in the liquid cannot follow the flow as the smaller particles do, or bigger particles will move slower than the liquid around them, so the velocities of particles will distribute dispersedly. Another possible reason is that when the velocity of flow increases the time for particles to traverse, the view field of the microscope will decrease. As a result, the number of data points in the trace of a particle... 

Therefore, fluorescent nano-particles can be used as the tracer in studying micro-fluids. The visualizing approach to nano-flow is not very mature and more experiments should be practiced. Because of its wide connection to modem technologies, the research of the solid-liquid two-phase flow will attract more and more attention. 

Properties of Thin Film Lubrication with Nano-Particles... 

In the 1990s, much progress in preparation and application of spherical or surface modihed nano-particles has been... 

Sarkar, J., Pal, P., and Talapatra, G. B., Self-Assembly of Silver Nano-particles on Stearic Acid Langmuir-Blodgett Film Evidence of Eractal Growth, Chem. Phys. Lett., Vol. 401, No. 4-6,2005, pp. 400 04. 

Fig. 4—Profile of a cylindrical liquid jet containing deionized water or a slurry with nano-particles impacting on a surface of a silicon wafer with an incident angle 6 at a speed v. (L=100 mm, <1>=2 mm, 0=45°.)...

Lee T.A.T., Cooper A., Apkarian R.P., and Conticello V.P. Thermo-reversible self-assembly of nano-particles derived from elastin-mimetic polypeptides. Advanced Materials, 12, 1105, 2000. 

FIGURE 19.1 Morphology of nano-filler in rubbery matrix Nano-particles are aggregated, and the aggregates also associate to give filler agglomerate in rubber. (From Kohjiya, S., Kato, A., Suda, T., Shimanuki, J., and Ikeda, Y., Polymer, Al, 3298, 2006. With permission.)... 

C. (1997) Synthesis of nano-particles of CaC03 in a novel reactor, in Process Intensification in Practice Applications and Opportunities (ed. J. Semel), Mechanical... 

J. A. Schwartz, C.I. Contescu, Surface of Nano-Particles and Porous Materials, Marcel Dekker, 1999. 

Fine particles including nano-particles have become of major interest lately. Many industrial sectors such as pharmaceutical, agriculture, foods, chemicals, ceramics and electronics are expected to find applications and take advantage of the new fimctionalities and many desirable properties attributed to the ultra small size. 

In order to tailor the physical properties of nano-particles, wet granulation was conducted. Hydroxypropylecellulose (HPC-L) 5% aqueous solution was sprayed onto nano-sized Ti02 particles through a binary nozzle. Fluidization air velocity was set at approximately 1.5 times as large as the minimum fluidization air velocity. 

Fig.3. Fluidization behaviors of nano particle (TiOj 21nm)...

Fig.4. Visualization of nano-particle fluidization (Top of the vessel, observation from front side)...

A fuel cell is a layered structure consisting of an anode, a cathode, and a solid electrolyte (Fig. 8.31). Hydrogen reacts on the anode, typically Pt or Pt/Ru nano-particles deposited on a conducting graphite support, where it is oxidized into protons and electrons ... 

Cortie, M.B. and van der Lingen, E. (2002) Catalytic gold nano-particles. Materials Forum, 26, 1-14. 

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