Hemispherical growth

For simultaneous three-dimensional (3D) hemispherical growth and instantaneous nucleation. 

As an example, diffusion-controlled hemispherical growths will be described. Hills, Schiffiin, and Thomson calculated the current of Nq individual nuclei that grow independently of each other. ... 

Other geometries have been considered using a similar approach, and a recent detailed examination of different three-dimensional models has been given by Bosco Rangarajan [20]. The solutions in the case of hemispherical growth centres are particularly interesting since they show maxima and minima in the approach to the final current density. The transients computed for instan-... 

The amount of dissolved metal and by assuming a hemispherical growth of the pit, the pit size can be calculated according to Faraday s law. The authors further state that due to the time required for scanning a certain area and the limit of current detection (about 2 pA cm ), not all of the pits can be measured by the SVET. Thus pits that initiate, propagate, and repassivate... 

Thin layers of electrochemically deposited metals and thin polymer layers deposited on electrode surfaces can be conveniently studied by ellipsometry combined with other electrochemical experiments. Electrocrystallization of nickel was studied by Abyaneh, Visscher, and Barendrecht with ellipsometry and simultaneous amperometric measurements. The initial changes in A and ij/ showed nonlinear variations with the deposition time (Fig. 12), which is apparently abnormal, indicating a marked deviation of the optical properties of the deposited film from the bulk metal properties. The observed trend was explained by theoretical calculations using equations of effective medium theory (see Section IV.4 for effective medium theory) for hemispherical growth of the nucleation centers. The observed ellipsometry data clearly demonstrate that in the initial stage of nonuniform deposition the measured parameters, ij/ in particular, can change in a... 

This growth resulted from additional countries entering as major producers of petroleum. By 1941, Venezuela was producing over one-half of the crude oil extracted in the Western Hemisphere. During this period as well, the Middle and Near East first began to flex its muscles as an oil producing region. Iran,... 

The formation of pores appears to start along the sub-grain boundaries of the metal, followed by the development of additional pores within the subgrains. Growth of oxide continues on a series of hemispherical fronts centred on the pore bases, provided that the effective barrier-layer thickness between the metal surface and the electrolyte within the pores, represented by the hemisphere radius, is less than 1-4 nm/V. As anodic oxidation proceeds at... 

Unidentified Stimulators. Growth-inhibitory materials in, or secreted by, plants have for the most part been emphasized in this paper. However, root secretions of many plants also contain constituents required for the germination of seeds of angiospermous root parasites (Striga, Orobanche, Alectra, and Sopubia genera). This phenomenon has been reviewed by Brown (17). Striga asiatica was identified for the first time in the western hemisphere in 1956 in two... 

ASME JSME Thermal Eng loint Conf Proc 5 455 62 Nigmatulin IR (1991) Dynamics of multiphase media and 2. Hemisphere, London Ory E, Yuan H, Prosperetti A, Popinet S, Zaleski S (2000) Growth and coUapse of vapor bubble in a narrow tube. Phys Fluids 12 1268-1277... 

In a real-time spectroellipsometric measurement in which the kinetics of a-Si H deposition is studied, trajectories are recorded in the A-4 plane at various photon energies between 2 and 4 eV. These trajectories can be simulated and fitted to models that represent the growing a-Si H layer. Canillas et al. [347] have made a detailed study of the deposition of the first few layers of a-Si H on a NiCr/glass substrate. Similar results are obtained for a c-Si substrate. They have proposed several models to explain the data. One possible model is the hemispherical nu-cleation model, which describes a hexagonal network of spherical a-Si H nuclei located at an average distance d between them. The growth is represented by an... 

For liquid metals the superiority of nucleate boiling heat transfer coefficients over those for forced-convection liquid-phase heat transfer is not as great as for ordinary liquids, primarily because the liquid-phase coefficients for liquid metals are already high, and the bubble growth period for liquid metals is a relatively short fraction of the total ebullition cycle compared with that for ordinary fluids. In the case of liquid metals, the initial shape of the bubbles is hemispheric, and it becomes spherical before leaving the heating surface. This is because of very rapid... 

Dwyer, O. E., and C. J. Hsu, 1976, Evaporation of the Microlayer in Hemispherical Bubble Growth in Nucleate Boiling of Liquid Metals, Int. J. Heat Mass Transfer 79 185. (2)... 

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