Analysis of Grain Structure in Partially Ordered Block Copolymers by Depolarized Light Scattering and Transmission Electron Microscopy

2002 ◽  
Vol 35 (11) ◽  
pp. 4437-4447 ◽  
Author(s):  
M. Y. Chang ◽  
F. M. Abuzaina ◽  
W. G. Kim ◽  
J. P. Gupton ◽  
B. A. Garetz ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Light Scattering ◽  
Block Copolymers ◽  
Grain Structure ◽  
Partially Ordered ◽  
Transmission Electron ◽  
Depolarized Light Scattering

Shear Induced Low- and High-Angle Boundary Characterization Using Kikuchi Bands in Transmission Electron Microscopy

2008 ◽  
Vol 584-586 ◽  
pp. 293-299 ◽  
Author(s):  
Marcello Cabibbo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cell Size ◽  
Grain Structure ◽  
Structure Evolution ◽  
High Angle ◽  
Boundary Misorientation ◽  
Average Cell Size ◽  
Average Cell ◽  
Transmission Electron

Microstructure evolution with equal channel angular pressing (ECAP) using route Bc, that is a 90° axial rotation of the billet between passes, up to 8 passes, was investigated by transmission electron microscopy. The study has been focused on the induced development of boundary misorientation and spacing toward microstructure refinement. Cell (low-angle) and grain (high-angle) misorientation and spacing were determined from about 250 boundaries per pass of ECAP, systematically using whether Kikuchi patterns or Moiré fringes, these latter where possible. The average cell size and misorientation saturate within the first two passes. Misorientation and spacing of high-angle boundaries decrease with the number of passes. After 8 passes, mean cell size is ≈ 1.3 µm and the fraction of high-angle boundaries is ≈ 0.7. Differences in rate of grain structure evolution per pass are linked to differences in ability of dislocations introduced in new passes to recombine with the existing ones. As ECAP strain rises, the misorientation distribution develops strong deviations from the MacKenzie distribution for statistical grain orientation. This is interpreted as a result of the tendency to form equiaxed grains in a textured grain structure.

Polyethyleneimine Modified Biocompatible Poly(N-isopropylacrylamide)-Based Nanogels for Drug Delivery

2008 ◽  
Vol 8 (5) ◽  
pp. 2377-2384 ◽  
Author(s):  
Chang-Yun Quan ◽  
Hua Wei ◽  
Yun-Xia Sun ◽  
Si-Xue Cheng ◽  
Kun Shen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Drug Delivery ◽  
Transmission Electron Microscopy ◽  
Light Scattering ◽  
Dynamic Light Scattering ◽  
Transmission Electron ◽  
Potential Applications ◽  
Different Temperatures ◽  
The Mean ◽  
Stimuli Sensitive

A series of biocompatible and stimuli-sensitive poly(N-isopropylacrylamide-co-propyl acrylic acid) (P(NIPAAm-co-PAAc)) nanogels were synthesized by emulsion polymerization. In addition, polyethyleneimine (PEI) was further grafted to modify the PNIPAAm-based nanogels. The P(NIPAAm-co-PAAc)-g-PEI nanogels exhibited good thermosensitivity as well as pH sensitivity. Transmission electron microscopy (TEM) showed that the P(NIPAAm-co-PAAc)-g-PEI and P(NIPAAm-co-PAAc) nanogels displayed well dispersed spherical morphology. The mean sizes of the nanogels measured by dynamic light scattering (DLS) were from 100 nm to 500 nm at different temperatures. The cytotoxicity study indicated P(NIPAAm-co-PAAc) nanogels exhibited a better biocompatibility than both PNIPAAm nanogel and P(NIPAAm-co-PAAc)-g-PEI nanogel although all the three kinds of nanogels did not exhibit apparent cytotoxicity. The drug-loaded nanogels, especially the PEI-grafted nanogels, showed temperature-trigged controlled release behaviors, indicating the potential applications as an intelligent drug delivery system.

Nucleation and Growth of the First Phase in Sputter-Deposited Nb/Al Multilayer Thin Films

1995 ◽  
Vol 398 ◽  
Author(s):  
K. Barmak ◽  
S. Vivekanand ◽  
F. Ma ◽  
C. Michaelsen
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Nucleation And Growth ◽  
Grain Structure ◽  
Multilayer Thin Films ◽  
Product Phase ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Sputter Deposited

ABSTRACTThe formation of the first phase in the reaction of sputter-deposited Nb/Al multilayer thin films has been studied by power-compensated and heat-flux differential scanning calorimetry, x-ray diffraction and transmission electron microscopy. The modulation periods of the films are in the range of 10-500 nm. Both types of calorimetrie measurements, performed at a constant heating rate, show the presence of two peaks (A and B) for the formation of the single product phase, NbAl3. Isothermal calorimetrie scans show that peak A is associated with a nucleation and growth type transformation. The formation of NbAl3 is thus interpreted as a two-stage process of nucleation and lateral growth to coalescence (peak A) followed by normal growth until the consumption of one or both reactants (peak B). Transmission electron microscopy investigations of samples annealed into the first stage of NbAl3 formation show the presence of this phase at the Nb/Al interface and its preferential growth along the grain boundaries of the Al layer. The latter highlights the role of reactant phase grain structure in product phase formation.

Preparation of Size and Morphology Controlled Gold Nanoparticles in Micro-Emulsion and in Aqueous

2012 ◽  
Vol 184-185 ◽  
pp. 1138-1141
Author(s):  
Yan Biao Zhang ◽  
Xiao Hui Zhang ◽  
Hong Zong Yin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Light Scattering ◽  
Homogeneous Distribution ◽  
Mass Ratio ◽  
Optimum Ratio ◽  
Transmission Electron ◽  
Micro Emulsion ◽  
Size And Morphology

In this study, we prepared gold nanoparticles in micro-emulsion and found the optimum ratio of micro-emulsion for preparing gold nanoparticles. We reported a new stabilizer for preparing gold nanoparticles in aqueous and found the optimum mass ratio between the stabilizer and chlorauric acid. All gold nanoparticles prepared by these two methods were characterized by transmission electron microscopy, ultraviolet-visible spectrophotometer and synchronous light-scattering spectrophotometer. The results of transmission electron microscopy showed that the diameter range of gold nanoparticles prepared in micro-emulsion was 5~10 nm, and that in aqueous was 10~15 nm. They all had homogeneous distribution and dense structures.

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