**7. References**

AIST Home Page, Research Information Database, Network Database System for Thermophysical Property Data, (2006),

http://riodb.ibase.aist.go.jp/TPDB/DBGVsupport/detail/silicon\_en.html.


Secondly, fluid dynamics concerning nanoparticle formation in a high speed flow was developed. Interactions between the shock waves and plume, generation of nuclei, and growth of nanoparticles could all be treated with a single calculation. We conducted onedimensional calculations with the equation, and found conditions wherein the timing of the nucleation and growth processes could be separated based on interactions between the shock wave and plume. The existence of certain conditions for nanoparticle formation in the narrow region between the plume and the buffer gas were confirmed from the numerical results. In addition, reflected shock waves substantially contribute to the growth of nanoparticles by increasing particle radius, but do not contribute to the increase of

A new model of nanoparticle generator, employing an ellipsoidal cell, was then formulated based on the results of the one-dimensional calculations. To evaluate the performance of the cell, axi-symmetric two-dimensional calculations were conducted using Navier-Stokes equations without nanoparticle formation. The behavior of shock wave and plume became clear with the use of density contour maps. The reflection and conversion of shock waves, the interaction between shock wave and plume, and ejection of gas through the cell exit

The ellipsoidal cell was manufactured and PLA process was experimentally carried out in the cell. Cu nanoparticles formed in the experiment were typically of uniform size, under 10 nm in diameter, and had a narrow size distribution, with a standard deviation around 1.1 for the lognormal distribution. The narrow distribution of nanoparticle size possibly originated from the effect of ellipsoidal cell, because the fine, uniform nano-sized particles could not be obtained unless the direction of plume ejection was coincident with the focal point of the ellipsoidal cell. Such uniformly sized nanoparticles are important for practical

Finally, the thermodynamics of nanoparticle sintering was explored, in particular the transition of nanoparticle appearance with changes in temperature, as well as the possibility of low temperature bonding. Since the melting point of nanoparticles sensitively depends on size, it is important to prepare uniformly sized nanoparticles for bonding at low

AIST Home Page, Research Information Database, Network Database System for

Camata, R. P., Atwater, H. A., Vahala, K. J. and Flagan, R. C. (1996), Size classification of

Chrisey, D.B. and Hubler G.K. (Eds.) (1994), Pulsed Laser Deposition of Thin Films, Wiley-

Finney, E. E. and Finke, R. G. (2008), Nanocluster nucleation and growth kinetic and

Fukuoka, H., Yaga, M. and Takiya, T. (2008), Study of Interaction between Unsteady

mechanistic studies: A review emphasizing transition-metal nanoclusters, Journal

Supersonic Jet and Shock Waves in Elliptical Cell, Journal of Fluid Science and

http://riodb.ibase.aist.go.jp/TPDB/DBGVsupport/detail/silicon\_en.html.

silicon nanocrystals, Appl. Phys. Lett. 68 (22), 3162-3164.

nanoparticle numbers by promoting nucleation.

use as indicated by the following example.

Interscience, New York.

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were clearly illustrated.

temperatures.

**7. References** 


**6** 

**Thermodynamics of the Oceanic General** 

The oceanic general circulation has been investigated mainly from a dynamic perspective. Nevertheless, some important contributions to the field have been made also from a thermodynamic viewpoint. This chapter presents description of the thermodynamics of the oceanic general circulation. Particularly, we examine entropy production of the oceanic general circulation and discuss its relation to a thermodynamic postulate of a steady closed circulation such as the oceanic general circulation: Sandström's theorem. Also in this section, we refer to another important thermodynamic postulate of an open non-equilibrium system such as the oceanic general circulation: the principle of Maximum

Oceanic general circulation is the largest current in the world ocean, making a circuit from the surface to the bottom over a few thousand years. The present oceanic general circulation, briefly speaking, is a series of flows, in which seawater sinks from restricted surface regions in high latitudes of the Atlantic Ocean to the deep bottom ocean. It later comes to broad surface regions of the Pacific Ocean, and returns to the Atlantic Ocean through the surface of the Indian Ocean (see Fig. 1). The atmosphere affects the daily weather, whereas the ocean affects the long-term climate because of its larger heat capacity. Therefore, it is important for

The causes generating the oceanic general circulation are momentum flux by wind stress at the sea surface and density flux by heating, cooling, precipitation, and evaporation through the sea surface, except for tides. In general, the oceanic general circulation is explained as consisting of surface (wind-driven) circulation attributable to the momentum flux and abyssal (thermohaline) circulation caused by the density flux. However, the distinction between them is not simple because diapycnal mixing, which is important for abyssal circulation, depends largely on wind, as described in the next sub-section. Moreover,

**1. Introduction**

Entropy Production.

**1.1 Outline of oceanic general circulation** 

our life to elucidate the oceanic general circulation.

diapycnal mixing depends also on tides.

**Circulation – Is the Abyssal Circulation** 

 **a Heat Engine or a Mechanical Pump?** 

Shinya Shimokawa1 and Hisashi Ozawa2

*1National Research Institute for Earth Science and Disaster Prevention* 

*2Hiroshima University* 

*Japan* 

