Formation of Thermally Induced Defects in Silica Optical Material

2013 ◽  
Vol 853 ◽  
pp. 62-67
Author(s):  
Zhong Yin Xiao ◽  
Jian Xiang Wen ◽  
Wen Yun Luo ◽  
Wen Kai Wu ◽  
Ren Xiang Gong ◽  
...  
Keyword(s):  
High Temperature ◽  
Formation Process ◽  
Thermal History ◽  
Defect Formation ◽  
Annealing Process ◽  
Optical Material ◽  
Thermally Induced ◽  
Silica Material ◽  
Heating Treatment ◽  
Induced Defects

Characteristics of silica optical material largely depend on its thermal history. In this paper, formation of thermally induced defects in silica optical material is studied. The formation process of defect is analyzed in detail. The results show that there is an obvious difference in defect formation induced by heating treatment when the composition of silica optical material changes. Defect formation mainly displays as the produce process when the initial defects of the silica material are zero. However, defect formation expresses as the produce and annealing process when the initial defects of the silica material are not zero. The initial defect concentration can be decreased significantly when the silica material is heated in high temperature. At the same time, the new defect is also produced. These theoretic results are consistent with the previous experimental ones.

Xenon ion irradiation of superconducting YBa2Cu3O7 thin films

1990 ◽  
Vol 48 (4) ◽  
pp. 92-93
Author(s):  
H. Watanabe ◽  
B. Kabius ◽  
B. Roas ◽  
K. Urban
Keyword(s):  
Defect Formation ◽  
Ion Irradiation ◽  
High Resolution Electron Microscopy ◽  
Structural Disorder ◽  
Flux Lines ◽  
Pinning Effect ◽  
Magnetic Flux Lines ◽  
Resolution Electron ◽  
Radiation Induced ◽  
Induced Defects

Recently it was reported that the critical current density(Jc) of YBa2Cu2O7, in the presence of magnetic field, is enhanced by ion irradiation. The enhancement is thought to be due to the pinning of the magnetic flux lines by radiation-induced defects or by structural disorder. The aim of the present study was to understand the fundamental mechanisms of the defect formation in association with the pinning effect in YBa2Cu3O7 by means of high-resolution electron microscopy(HRTEM).The YBa2Cu3O7 specimens were prepared by laser ablation in an insitu process. During deposition, a substrate temperature and oxygen atmosphere were kept at about 1073 K and 0.4 mbar, respectively. In this way high quality epitaxially films can be obtained with the caxis parallel to the <100 > SrTiO3 substrate normal. The specimens were irradiated at a temperature of 77 K with 173 MeV Xe ions up to a dose of 3.0 × 1016 m−2.

Study of high-pressure air jet controlled compression ignition with compound thermodynamic cycle for combustion and emission formation process

2020 ◽  
pp. 146808742096933
Author(s):  
Xiangyu Meng ◽  
Sicheng Liu ◽  
Jingchen Cui ◽  
Jiangping Tian ◽  
Wuqiang Long ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Low Temperature ◽  
Formation Process ◽  
Combustion Process ◽  
Thermodynamic Cycle ◽  
Compression Ignition ◽  
Temperature Reaction ◽  
Air Jet ◽  
High Temperature Reaction

A novel method called high-pressure air (HPA) jet controlled compression ignition (JCCI) based on the compound thermodynamic cycle was investigated in this work. The combustion process of premixed mixture can be controlled flexibly by the high-pressure air jet compression, and it characterizes the intensified low-temperature reaction and two-stage high-temperature reaction. The three-dimensional (3D) computational fluid dynamics (CFD) numerical simulation was employed to study the emission formation process and mechanism, and the effects of high-pressure air jet temperature and duration on emissions were also investigated. The simulation results showed that the NOx formation is mainly affected by the first-stage high-temperature reaction due to the higher reaction temperature. Overall, this combustion mode can obtain ultra-low NOx emission. The second-stage high-temperature reaction plays an important role in the CO and THC formation caused by the mixing effect of the high-pressure air and original in-cylinder mixture. The increasing air jet temperature leads to a larger high-temperature in-cylinder region and more fuel in the first-stage reaction, and therefore resulting in higher NOx emission. However, the increasing air jet temperature can significantly reduce the CO and THC emissions. For the air jet duration comparisons, both too short and too long air jet durations could induce higher NOx emission. A higher air jet duration would result in higher CO emission due to the more high-pressure air jet with relatively low temperature.

Measurement and interpretation of stress in copper films as a function of thermal history

1991 ◽  
Vol 6 (7) ◽  
pp. 1498-1501 ◽  
Author(s):  
Paul A. Flinn
Keyword(s):  
Mechanical Properties ◽  
Thermal Expansion ◽  
Elastic Modulus ◽  
Thermal History ◽  
Copper Films ◽  
Thermally Induced ◽  
Aluminum Films ◽  
Interconnection Material ◽  
Interconnect Systems

Since copper has some advantages relative to aluminum as an interconnection material, it is appropriate to investigate its mechanical properties in order to be prepared in advance for possible problems, such as the cracks and voids that have plagued aluminum interconnect systems. A model previously used to interpret the behavior of aluminum films proves to be, with minor modification, also applicable to copper. Although the thermal expansion of copper is closer to that of silicon and, consequently, the thermally induced strains are smaller, the much larger elastic modulus of copper results in substantially higher stresses. This has implications for the interaction of copper lines with dielectrics.

Thermally induced defects in a polycrystalline diamond layer on a tungsten carbide substrate

2009 ◽  
Vol 404 (22) ◽  
pp. 4485-4488 ◽  
Author(s):  
B.N. Masina ◽  
A. Forbes ◽  
O.M. Ndwandwe ◽  
G. Hearne ◽  
B.W. Mwakikunga ◽  
...  
Keyword(s):  
Tungsten Carbide ◽  
Polycrystalline Diamond ◽  
Thermally Induced ◽  
Diamond Layer ◽  
Induced Defects

scholarly journals X-ray Based in Situ Investigation of Silicon Growth Mechanism Dynamics—Application to Grain and Defect Formation

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 555 ◽  
Author(s):  
Hadjer Ouaddah ◽  
Maike Becker ◽  
Thècle Riberi-Béridot ◽  
Maria Tsoutsouva ◽  
Vasiliki Stamelou ◽  
...  
Keyword(s):  
High Temperature ◽  
Defect Formation ◽  
Imaging Techniques ◽  
Original System ◽  
Bragg Diffraction ◽  
Grain Structure ◽  
Structural Defects ◽  
X Ray ◽  
In Situ Investigation

To control the final grain structure and the density of structural crystalline defects in silicon (Si) ingots is still a main issue for Si used in photovoltaic solar cells. It concerns both innovative and conventional fabrication processes. Due to the dynamic essence of the phenomena and to the coupling of mechanisms at different scales, the post-mortem study of the solidified ingots gives limited results. In the past years, we developed an original system named GaTSBI for Growth at high Temperature observed by Synchrotron Beam Imaging, to investigate in situ the mechanisms involved during solidification. X-ray radiography and X-ray Bragg diffraction imaging (topography) are combined and implemented together with the running of a high temperature (up to 2073 K) solidification furnace. The experiments are conducted at the European Synchrotron Radiation Facility (ESRF). Both imaging techniques provide in situ and real time information during growth on the morphology and kinetics of the solid/liquid (S/L) interface, as well as on the deformation of the crystal structure and on the dynamics of structural defects including dislocations. Essential features of twinning, grain nucleation, competition, strain building, and dislocations during Si solidification are characterized and allow a deeper understanding of the fundamental mechanisms of its growth.

Thermally Induced Defects on WSe2

2020 ◽  
Vol 124 (28) ◽  
pp. 15337-15346 ◽  
Author(s):  
William H. Blades ◽  
Nicholas J. Frady ◽  
Peter M. Litwin ◽  
Stephen J. McDonnell ◽  
Petra Reinke
Keyword(s):  
Thermally Induced ◽  
Induced Defects

Millisecond tension-annealing for enhancing carbon nanotube fibers

Nanoscale ◽  
2019 ◽  
Vol 11 (29) ◽  
pp. 13909-13916 ◽  
Author(s):  
Yanhui Song ◽  
Jiangtao Di ◽  
Chao Zhang ◽  
Jingna Zhao ◽  
Yongyi Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Carbon Nanotube ◽  
Joule Heating ◽  
Annealing Process ◽  
Carbon Nanotube Fibers

A millisecond tension-annealing process by high-temperature Joule heating was proposed to fast align CNTs and strongly crosslink the neighbouring CNTs in the CNT fibers.

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