Electron microscope evidence of a macroscopic ‘single crystal’ from a three block copolymer

1970 ◽  
Vol 242 (1-2) ◽  
pp. 1125-1130 ◽  
Author(s):  
J. Dlugosz ◽  
A. Keller ◽  
E. Pedemonte
Author(s):  
Z.L. Wang

An experimental technique for performing electron holography using a non-FEG, non-biprism transmission electron microscope (TEM) has been introduced by Ru et al. A double stacked specimens, one being a single crystal foil and the other the specimen, are loaded in the normal specimen position in TEM. The single crystal, which is placed onto the specimen, is responsible to produce two beams that are equivalent to two virtual coherent sources illuminating the specimen beneath, thus, permitting electron holography of the specimen. In this paper, the imaging theory of this technique is described. Procedures are introduced for digitally reconstructing the holograms.


Author(s):  
D. S. Pritchard

The effect of varying the strain rate loading conditions in compression on a copper single crystal dispersion-hardened with SiO2 particles has been examined. These particles appear as small spherical inclusions in the copper lattice and have a volume fraction of 0.6%. The structure of representative crystals was examined prior to any testing on a transmission electron microscope (TEM) to determine the nature of the dislocations initially present in the tested crystals. Only a few scattered edge and screw dislocations were viewed in those specimens.


Author(s):  
R. B. Neder ◽  
M. Burghammer ◽  
Th. Grasl ◽  
H. Schulz

AbstractWe developed a new micro manipulator for mounting individual sub-micrometer sized single crystals within a scanning electron microscope. The translations are realized via a commercially available piezomicroscope, adapted for high vacuum usage and realize nanometer resolution. With this novel instrument it is routinely possible to mount individual single crystals with sizes down to 0.1


2011 ◽  
Vol 284-286 ◽  
pp. 1584-1587
Author(s):  
Zhen Xue Shi ◽  
Jia Rong Li ◽  
Shi Zhong Liu ◽  
Jin Qian Zhao

The specimens of low angle boundaries were machined from the second generation single crystal superalloy DD6 blades. The microstructures of low angle boundaries (LAB) were investigated from three scales of dendrite, γ′ phase and atom with optical microscopy (OM), scanning electron microscope (SEM), transition electron microscope (TEM) and high resolution transmission electrion microscopy (HREM). The results showed that on the dendrite scale LAB is interdendrite district formed by three dimensional curved face between the adjacent dendrites. On the γ′ phase scale LAB is composed by a thin layer γ phase and its bilateral imperfect cube γ′ phase. On the atom scale LAB is made up of dislocations within several atom thickness.


2018 ◽  
Vol 8 (10) ◽  
pp. 1794 ◽  
Author(s):  
Fang Zhou ◽  
Yujing Zhao ◽  
Weichang Zhou ◽  
Dongsheng Tang

Bi 2 Se 3 has extensive application as thermoelectric materials. Here, large-scale Bi 2 Se 3 single-crystal hexagonal nanoplates with size 7.50–10.0 μ m were synthesized successfully by hydrothermal method. X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to characterize the Bi 2 Se 3 nanoplates, which confirm the single-crystal quality and smooth surface morphology with large size. Micro-Raman spectra over a temperature range of 83–603 K were furthermore used to investigate the lattice dynamics of Bi 2 Se 3 nanoplates. Both 2A g 1 and 1E g 2 modes shift evidently with reduced temperature. The line shape demonstrates a significant broadening of full width at half maximum (FWHM) and red-shift of frequency with increased temperature. The temperature coefficient of A 1 g 1 , E g 2 , A 1 g 2 modes were determined to be −1.258 × 10 − 2 cm − 1 /K, −1.385 × 10 − 2 cm − 1 /K, −2.363 × 10 − 2 cm − 1 /K, respectively. Such low temperature coefficient may favor the obtaining of a high figure of merit (ZT) and indicate that Bi 2 Se 3 nanoplates were used as excellent candidates of thermoelectric materials.


Microscopy ◽  
2020 ◽  
Vol 69 (6) ◽  
pp. 411-416
Author(s):  
Tetsuya Akashi ◽  
Yoshio Takahashi ◽  
Ken Harada

Abstract We have developed an amplitude-division type Mach-Zehnder electron interferometer (MZ-EI). The developed MZ-EI is composed of single crystals corresponding to amplitude-division beam splitters, lenses corresponding to mirrors and an objective aperture. The spacings and azimuth angles of interference fringes can be controlled by single crystal materials and their orientations and by diffraction spots selected by the objective aperture. We built the MZ-EI on a 1.2-MV field-emission transmission electron microscope and tested its performance. Results showed that interference fringes were created for various spacings and azimuth angles, which demonstrates the practicability of the MZ-EI as an amplitude-division type electron interferometer.


2020 ◽  
Vol 155 ◽  
pp. 01005
Author(s):  
Weiwei Liu ◽  
Yuanyuan Guo ◽  
Mai Zhang ◽  
Jian Zhang

A Re-containing single-crystal superalloy was used to research the high temperature low stress creep behavior. Transmission electron microscope, scanning electron microscope and some other research methods are employed. The results and analysis are summarized below: Two mechanisms for the steady creep are found in this experiment. The volume fraction of pores after creep test at 1100°C increased more than 2 times compared with that before test, but the increasing at 1000°C is relatively small, which reveals that temperature has an great influence on the formation of pore during creep; There are two types of pores associated with fracture during the creep process. One is the casting shrinkage located between the interdentritic, which is formed in the solidification of the alloy. Another type of pore is nucleated and growing during the creep deformation.


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