Surface diffusion and surface crystal growth of tris-naphthyl benzene glasses

2016 ◽  
Vol 145 (6) ◽  
pp. 064503 ◽  
Author(s):  
Shigang Ruan ◽  
Wei Zhang ◽  
Ye Sun ◽  
M. D. Ediger ◽  
Lian Yu
2021 ◽  
Author(s):  
Fajar Inggit Pambudi ◽  
Michael William Anderson ◽  
Martin Attfield

Atomic force microscopy has been used to determine the surface crystal growth of two isostructural metal-organic frameworks, [Zn2(ndc)2(dabco)] (ndc = 1,4-naphthalene dicarboxylate, dabco = 4-diazabicyclo[2.2.2]octane) (1) and [Cu2(ndc)2(dabco)] (2) from...


1992 ◽  
Vol 280 ◽  
Author(s):  
F. L. Metcalfe ◽  
J. A. Venables

ABSTRACTCrystal growth and surface diffusion have been studied in the Ag/Ge(lll) system using UHV-SEM based techniques, biassed secondary electron imaging (b-SEI), micro-AES and RHEED. Ag was deposited through and past a mask of holes held close to the substrate at 300<Td< 775K. Under certain conditions, the Ag patches were observed to split into two regions corresponding to the √3×√3R30° (hereafter √3) and a lower coverage 4×4 structure, each of which were easily observable using b-SEI. These patch widths were measured as a function of Td, and of annealing times at temperatures Ta, and effective diffusion coefficents extracted. The diffusion length of adatoms over the 4×4 structure is larger than that over the √3 structure. These observations are modelled using kinetic rate equations, and the results are compared with previous studies of Ag/Si(111). We find that energies characterising processes on top of the √3 layers of both systems are very similar, but that processes involved in the formation of the layers are quite different. The coverage of the √3 Ag/Ge(111) layer is close to 1 ML for all Td studied, unlike √3 Ag/Si(111). where it depends on deposition and annealing conditions.


2021 ◽  
Vol 54 (5) ◽  
Author(s):  
Qin Shi ◽  
Fang Li ◽  
Jia Xu ◽  
Lingling Wu ◽  
Junbo Xin ◽  
...  

Physical stability is one of the main challenges when developing robust amorphous pharmaceutical formulations. This article reports fast crystal growth behaviors of the γ and α forms of indomethacin (IMC) initiated by bubbles in the interior of a supercooled liquid. Bubble-induced crystal growth of γ-IMC exhibits approximately the same kinetics as its surface crystal growth, supporting the view that bubble-induced crystal growth is a surface-facilitated process. In contrast, the rates of bubble-induced crystal growth of α-IMC are much faster than those of its surface crystal growth. These results indicate that the bubble-induced crystal growth not only depends on the interface created by the bubble but also strongly correlates with the true cavitation of the bubble. Moreover, bubble-induced fast crystal growth of γ- and α-IMC can be terminated at different temperatures by cooling. These outcomes are meaningful for the in-depth understanding of physical stability and pre-formulation study of amorphous pharmaceutical solids showing surface-facilitated crystal growth.


1986 ◽  
Vol 49 (6) ◽  
pp. 421-422 ◽  
Author(s):  
STEPHEN T. DYBING ◽  
STEVEN A. BRUDVIG ◽  
JAMES A. WIEGAND ◽  
EMIL A. HUANG

A simple, non-destructive method for estimating the extent of crystal development as white specks on the surface of colored Cheddar cheese is described. This method involves photocopying the surface of the cheese with a photocopier set at an exposure calibrated to clearly show the crystals. The photocopies of the cheese surface are then compared to a series of photocopies showing designated increases in crystal growth. Crystal development was rated as follows: 0 = no crystals, 1= light, 2 = medium, 3 = heavy, and 4 = very heavy to encrusted crystal development. The method does not disrupt or destroy the environmental conditions existing in the cheese package, allowing extended shelf life studies to be done on the same piece of cheese. However, the photocopy technique may not work as well with white cheese or cheeses without flat surfaces.


2016 ◽  
Vol 16 (5) ◽  
pp. 2931-2936 ◽  
Author(s):  
Daniele Musumeci ◽  
Mariko Hasebe ◽  
Lian Yu

2010 ◽  
Vol 35 (21) ◽  
pp. 3625 ◽  
Author(s):  
David W. Lamb ◽  
Martijn Boerkamp ◽  
Peter G. Lye

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