The Crystal-Melt Interface in Si or Ge

1995 ◽  
Vol 398 ◽  
Author(s):  
Frans Spaepen ◽  
Yan Shao

ABSTRACTFrom the nucleation data on undercooling of liquid Si or Ge, crystal-melt interfacial tensions are calculated. Only a temperature-dependent tension can account simultaneously for the results of experiments on bulk and thin film Si. The observed temperature dependence can be accounted for by reasonable values of the interfacial entropy and enthalpy. The analysis is used to determine the temperature-dependent interfacial tension for Ge. A comparison of results for Ge and Si indicates that homogeneous nucleation has not been achieved in the undercooling of bulk liquid Si.

Author(s):  
S. M. Sohel Murshed ◽  
Nam-Trung Nguyen

Investigations on temperature dependence of surface tension, interfacial tension and viscosity a nanofluid are reported in this paper. Experimental results show that nanofluid having TiO2 nanoparticles (15 nm) in deionized water exhibit substantially smaller surface tension and oil-based interfacial tension than those of the base fluid (i.e. deionized water). These surface and interfacial tensions of this nanofluid were found to decrease almost linearly with increasing temperature. The Brownian motion of nanoparticles in base fluid was identified as a possible mechanism for reduced surface and interfacial tensions of nanofluid. The measured effective viscosity of nanofluid was found to be insignificantly higher than that of base fluid and it also decreases with increasing fluid temperature.


1986 ◽  
Vol 41 (1-2) ◽  
pp. 171-174 ◽  
Author(s):  
M. Frank ◽  
F. Gubitz ◽  
W. Ittner ◽  
W. Kreische ◽  
A. Labahn ◽  
...  

The 19F quadrupole coupling constants in CF4, CHF3, CClF3 and CHClF2 are reported. The measurements were carried out temperature dependent using the time differential perturbed angular distribution method (TDPAD). The temperature dependence can be satisfactorily described in the framework of the Bayer-Kushida theory. A simple model is used to explain the appearance of H-F and Cl-F coupling constants in CHF3/CHClF2 and CClF3, respectively.


2001 ◽  
Vol 679 ◽  
Author(s):  
Stephen B. Cronin ◽  
Yu-Ming Lin ◽  
Oded Rabin ◽  
Marcie R. Black ◽  
Gene Dresselhaus ◽  
...  

ABSTRACTThe pressure filling of anodic alumina templates with molten bismuth has been used to synthesize single crystalline bismuth nanowires with diameters ranging from 7 to 200nm and lengths of 50μm. The nanowires are separated by dissolving the template, and electrodes are affixed to single Bi nanowires on Si substrates. A focused ion beam (FIB) technique is used first to sputter off the oxide from the nanowires with a Ga ion beam and then to deposit Pt without breaking vacuum. The resistivity of a 200nm diameter Bi nanowire is found to be only slightly greater than the bulk value, while preliminary measurements indicate that the resistivity of a 100nm diameter nanowire is significantly larger than bulk. The temperature dependence of the resistivity of a 100nm nanowire is modeled by considering the temperature dependent band parameters and the quantized band structure of the nanowires. This theoretical model is consistent with the experimental results.


2015 ◽  
Vol 30 (11) ◽  
pp. 115020 ◽  
Author(s):  
Dong Wook Kim ◽  
Hyunji Shin ◽  
Ji-Ho Park ◽  
Jaehoon Park ◽  
Jong Sun Choi

1965 ◽  
Vol 87 (3) ◽  
pp. 735-739 ◽  
Author(s):  
Y. Tamai ◽  
B. G. Rightmire

Experimental work was carried out on the boundary lubrication of a copper-copper couple with pure cetane, palmitic acid solution of cetane, and some other organic materials. The purpose was to get information about α and μlube, which appear in the friction equation: μ=αμsolid+(1−α)μlube, by using two different kinds of copper surface, a clean surface, and an oxidized surface. α was found to be small with palmitic acid solution, and the estimated shear strength of palmitic acid was high under the examined condition. α and μlube seemed to be properties which are independent of each other. α is closely related to the attraction force between the lubricant and the substrate, whereas μlube is related to the complexity of molecular structure of the lubricant. A comparison was made of bulk-liquid and thin-film lubrication. μlube was smaller in thin-film lubrication than it was in bulk-liquid lubrication. This suggests that the frictional resistance may be partly contributed by liquid in the edge space around the real contact.


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