scholarly journals Effect of high current density to defect generation of blue LED and its characterization with transmission electron microscope

2018 ◽  
Vol 985 ◽  
pp. 012023
Author(s):  
R Gunawan ◽  
E Sugiarti ◽  
Isnaeni ◽  
R I Purawiardi ◽  
H Widodo ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Current Density ◽  
High Current Density ◽  
High Current ◽  
Blue Led ◽  
Defect Generation ◽  
Transmission Electron

Preparation of lignite-based activated carbon with high specific capacitance for electrochemical capacitors

2015 ◽  
Vol 08 (04) ◽  
pp. 1550031 ◽  
Author(s):  
Baolin Xing ◽  
Jianliang Cao ◽  
Yan Wang ◽  
Guiyun Yi ◽  
Chuanxiang Zhang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Electron Microscope ◽  
Specific Capacitance ◽  
Current Density ◽  
Electrode Materials ◽  
High Current Density ◽  
Electrochemical Capacitors ◽  
High Specific Capacitance ◽  
High Current ◽  
Charge Discharge

A lignite-based activated carbon (LAC) for electrochemical capacitors (ECs) was prepared from high moisture lignite by KOH activation, and the as-prepared sample was characterized by the N 2-sorption, scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The electrochemical performances of ECs with activated carbon as electrodes in 3 M KOH aqueous solution were evaluated by constant current charge-discharge and cyclic voltammetry. The LAC exhibits a well-developed surface area of 2581 m2/g, a relative wide pore size distribution of 0.5–10 nm. The ECs with LAC as electrode materials presents a high specific capacitance of 392 F/g at a low current density of 50 mA/g, and still remains 315 F/g even at a high current density of 5 A/g. The residual specific capacitance is as high as 92.9% after 2000 cycles. Compared with the commercial activated carbon (Maxsorb: Commercial product, Kansai, Japan), the LAC based electrode materials shows superior capacitive performance in terms of specific capacitance and charge–discharge performance at the high current density.

Electron Beam Induced Nanometre Hole Formation and Surface Modification in Al, Si And MgO

1989 ◽  
Vol 157 ◽  
Author(s):  
Tim J. Bullough ◽  
C. J. Humphreys ◽  
R. W. Devenish
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Electron Probe ◽  
High Current Density ◽  
Rapid Development ◽  
Atomic Scale ◽  
Exit Surface ◽  
Transmission Electron ◽  
Stationary Electron

ABSTRACTA wide variety of materials which are normally undamaged when exposed to a lOOkeV electron beam in a conventional transmission electron microscope can be modified on a nanometre scale by the high current density electron probe in a dedicated scanning transmission electron microscope (STEM). A stationary 100keV STEM electron probe can produce holes typically l-5nm diameter through crystalline Al, Si and MgO tens of nanometres in thickness, while a scanned electron beam can smooth surfaces on an atomic scale.In Al the stationary electron probe in the STEM produces a row of facetted voids along the irradiated volume. The voids grow initially inwards from the electron exit surface, with each void typically 4nm in diameter and 12-24nm in length, separated by equal distances from one another. In contrast, continuous holes 1.2-1.6nm diameter form at the electron exit surface of Si when exposed to the focused electron beam. However, these holes form only at specific randomly distributed points separated from one another by 2-4nm over the surface of crystalline specimens of both n- and p-doped <001> and <111> Si.Square cross-section holes with widths of about lnm can be formed by the stationary electron probe in MgO crystals. Rastering the probe over a restricted area of MgO initially results in the rapid development of surface islands and channels which are subsequently removed to leave an atomically smooth surface.

Formation of nanophases in a Cu–Zn alloy under high current density electropulsing

2000 ◽  
Vol 15 (10) ◽  
pp. 2065-2068 ◽  
Author(s):  
W. Zhang ◽  
M. L. Sui ◽  
K. Y. Hu ◽  
D. X. Li ◽  
X. N. Guo ◽  
...  
Keyword(s):  
Current Density ◽  
High Current Density ◽  
High Energy ◽  
Coarse Grained ◽  
High Current ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Before And After ◽  
Electropulsing Treatment ◽  
Zn Alloy

The microstructure of samples before and after a high current density electropulsing treatment was characterized by using high-resolution transmission electron microscopy. It has been found that in the coarse-grained Cu–Zn alloy subjected to the electropulsing treatment, two nanophases were formed, α–Cu(Zn) and β′–(CuZn), the average grain size of which is about 11 nm. A possible mechanism for the formation of nanophases was proposed. The experimental results indicated that electropulsing, as an instantaneous high-energy input, plays an important role in the nonequilibrium microstructural changes in materials and serves as a potential processing approach to synthesize nanostructured materials.

scholarly journals Cathodoluminescence of Y2O3:Ln3+ (Ln = Tb, Er and Tm) and Y2O3:Bi3+ nanocrystalline particles at 200 keV

RSC Advances ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 396-405 ◽  
Author(s):  
Daniel den Engelsen ◽  
George R. Fern ◽  
Terry G. Ireland ◽  
Jack Silver
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Current Density ◽  
Transmission Electron ◽  
Nanocrystalline Particles

The cathodoluminescence (CL) spectra of nanocrystalline Y2O3:Tb3+ (0.3%), Y2O3:Er3+ (1%), Y2O3:Tm3+ (2%) and Y2O3:Bi3+ (1%) were recorded in a transmission electron microscope at 200 keV, low current density and various temperatures.

Formation of a Nanostructure in a Low-carbon Steel Under High Current Density Electropulsing

2002 ◽  
Vol 17 (5) ◽  
pp. 921-924 ◽  
Author(s):  
Yizhou Zhou ◽  
Wei Zhang ◽  
Manling Sui ◽  
Douxing Li ◽  
Guanhu He ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Current Density ◽  
High Current Density ◽  
Low Carbon Steel ◽  
Coarse Grained ◽  
High Current ◽  
Low Carbon ◽  
Crystalline Materials ◽  
Transmission Electron ◽  
Electropulsing Treatment

The microstructure of a low-carbon steel after high current density electropulsing treatment was characterized by high-resolution transmission electron microscopy. It was found that nanostructured γ-Fe could be formed in the coarse-grained steel after the electropulsing treatment. The mechanism of the formation of a nanostructure was discussed. It was thought that change of the thermodynamic barrier during phase transformation under electropulsing was a factor that cannot be neglected. It was reasonable to anticipate that a new method might be developed to produce nanostructured materials directly from the conventional coarse-grained crystalline materials by applying high current density electropulsing.

scholarly journals Electron-Irradiation-Induced Crystallization of Amorphous Orthophosphates

1996 ◽  
Vol 439 ◽  
Author(s):  
A. Meldrum ◽  
L. A. Boatner ◽  
R. C. Ewing
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Amorphous Matrix ◽  
High Current Density ◽  
High Current ◽  
Transmission Electron ◽  
Oriented Polycrystalline ◽  
Current Densities ◽  
Induced Crystallization ◽  
Inelastic Processes

AbstractAmorphous LaPO4, EuPO4, GdPO4, ScPO4, LuPO4, and fluorapatite [Ca5(PO4)3F] were irradiated by the electron beam in a transmission electron microscope. Irradiations were performed over a range of temperatures from −150 to 300 °C, electron energies from 80 to 200 keV, and current densities from 0.3 to 16 A/cm2. In all cases, the materials crystallized to form a randomly oriented polycrystalline assemblage. Crystallization is driven dominantly by inelastic processes, although ballistic collisions with the target nuclei can become important at energies higher than 175 keV, particularly in apatite. Using a high current density, crystallization is so fast that continuous lines of crystallites can be “drawn” on the amorphous matrix.

Reversible bending of Si3N4 nanowire

2000 ◽  
Vol 15 (5) ◽  
pp. 1048-1051 ◽  
Author(s):  
Yingjiu Zhang ◽  
Nanlin Wang ◽  
Rongrui He ◽  
Qi Zhang ◽  
Jing Zhu ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Current Density ◽  
Bending Strength ◽  
Electrostatic Force ◽  
Transmission Electron ◽  
High Flexibility

A reversible bending phenomenon of Si3N4 nanowires on the conductive carbon–formalin microgrid under an illumination of electron beam was observed using a transmission electron microscope. The nanowires exhibit high flexibility. The bending deflection is approximately proportional to the square of the current density (J) of the electron beam. The bending strength of Si3N4 nanowire is much higher than that of bulk Si3N4 materials. The force that bent the nanowires may be an electrostatic force.

A Reproducible Selective Stain for Cardiac Sarcoplasmic Reticulum

1974 ◽  
Vol 32 ◽  
pp. 214-215
Author(s):  
R. A. Waugh ◽  
J. R. Sommer
Keyword(s):  
Complex System ◽  
Electron Microscope ◽  
Sarcoplasmic Reticulum ◽  
Transmission Electron Microscope ◽  
Electron Microscopic ◽  
Cardiac Sarcoplasmic Reticulum ◽  
Transmission Electron

Cardiac sarcoplasmic reticulum (SR) is a complex system of intracellular tubules that, due to their small size and juxtaposition to such electron-dense structures as mitochondria and myofibrils, are often inconspicuous in conventionally prepared electron microscopic material. This study reports a method with which the SR is selectively “stained” which facilitates visualizationwith the transmission electron microscope.

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