Activities Using Process‐Oriented Guided Inquiry Learning (POGIL) in the Foreign Language Classroom

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/89484/1/j.1756-1221.2011.00090.x.pd

Surface structure and solidification morphology of aluminum nanoclusters

Classical molecular dynamics simulation with embedded atom method potential had been performed to investigate the surface structure and solidification morphology of aluminum nanoclusters Aln (n = 256, 604, 1220 and 2048). It is found that Al cluster surfaces are comprised of (111) and (001) crystal planes. (110) crystal plane is not found on Al cluster surfaces in our simulation. On the surfaces of smaller Al clusters (n = 256 and 604), (111) crystal planes are dominant. On larger Al clusters (n = 1220 and 2048), (111) planes are still dominant but (001) planes can not be neglected. Atomic density on cluster (111)/(001) surface is smaller/larger than the corresponding value on bulk surface. Computational analysis on total surface area and surface energies indicates that the total surface energy of an ideal Al nanocluster has the minimum value when (001) planes occupy 25% of the total surface area. We predict that a melted Al cluster will be a truncated octahedron after equilibrium solidification.Comment: 22 pages, 6 figures, 34 reference

Dissolution Potentials And Activation Energies Of InSb Single Crystals

The rest (or corrosion) and dissolution potentials of InSb single crystals in HC1 were determined. There is no potential difference (within error limits) between the inverse {111} faces in pure HC1. A difference of up to 44 mV and more develops as soon as the InSb electrode is anodically dissolved. The potential becomes less noble in the sequence In{111}, {100}, {110}, Sb{111}. The Tafel relationship is observed over three decades of current density. With additions of FeCl3, FeCl2, K3Fe(CN)6, K4Fe(CN)6, H2C4H4O6 to 2N HC1, the anodic potentials of both inverse {111} faces are shifted to more active values; the e\u27H of In{111} is always nobler than that of Sb{111}. There are indications that the various potentials observed are a function of current density within the pores of a protective layer, Sb^OsCU. The apparent activation energy, ca. 20 kcal/mole, of the anodic dissolution reaction is nearly the same on all crystallography planes of InSb. The rate of anodic dissolution of Sb{111} in pure 2N HC1 is 3-7 times larger than that of the inverse face at the same potential. © 1972, by The Electrochemical Society, Inc. All rights reserved

Thermal Expansion Of Tungsten At Low Temperatures

Lattice parameters, thermal expansion coefficients, and Grüneisen parameters of tungsten are determined by an x-ray method in the temperature range of 180-40 K without the use of liquid gases. Lattice parameters are expressed as a function of temperature. Thermal-expansion coefficients decrease with temperature and show no anomaly in contrast to a hypothesis proposed by Featherston and Neighbours. Grüneisen parameters γ are decreasing with temperature in accordance with the theoretical predictions. © 1971 The American Institute of Physics

The Anodic Dissolution Reaction Of InSb: Etch Patterns, Electron Number, Anodic Disintegration, And Film Formation

The etching behavior of the inverse {111} planes of undoped, semiconducting, n-type, InSb single crystals was explored. Depending upon the etchant, including anodic dissolution, various etch patterns were obtained on the inverse planes. In general, the etch pits on the In{111} plane were round, and the face was shiny, whereas the face of the inverse plane was dark and rough. The rates of dissolution in the electrolytes used were very low, especially in absence of oxidizers. The components dissolve as In3+ and Sb3 +. At current densities above 40 or 60 mA cm-2 (on Sb{111} or In{111}), growth of a black, colloidal film of Sb4O5Cl2 containing very fine metallic Sb particles occurs on both planes. The Sb particles result from the partial disintegration of InSb. Upon heating the film in vacuum, recrystallization occurs and the Sb aggregates to form larger particles. An explanation is offered for the different behaviors of the inverse {111} planes. © 1971, by The Electrochemical Society, Inc. All rights reserved

Thermal Expansion Behavior Of Silicon At Low Temperatures

Lattice parameters, thermal expansion coefficients and Grüneisen parameters of silicon are determined by an X-Ray diffraction method in the temperature range of 180-40 K without the use of liquid gases. Thermal expansion of silicon becomes negative below 120 K which is discussed in terms of its lattice vibrations and crystal structure. © 1972