scholarly journals Structural damage characteristics of MoSe2 nanosheets irradiated by oxygen ions

2022 ◽  
pp. 105184
Author(s):  
Honglian Song ◽  
Xiaofei Yu
2022 ◽  
Vol 143 ◽  
pp. 104625
Author(s):  
Haibo Wang ◽  
Chengchao Guo ◽  
Fuming Wang ◽  
Pengpeng Ni ◽  
Wei Sun

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Qian Ma ◽  
Ke Wang ◽  
Shudong Wang ◽  
Yiwei Ouyang ◽  
Zhiqiang Lin ◽  
...  

AbstractThe most attractive structural feature of the three-dimensional (3D) angle-interlock woven structure is that the straight weft yarns are bundled by the undulated warp yarns, which induces the overall good structural stability and a stable fabric structure. Thus the 3-D angle-interlock woven composite (3DAWC) prepared by the vacuum-assisted resin transfer molding (VARTM) curing process has excellent mechanical properties by using the fabric and epoxy resin as the reinforcement and matrix, respectively. The low-velocity impact damage properties of the composites under different drop-weight energies (70, 80, and 100 J) were tested experimentally. The load–displacement curves, energy–time curves, and the ultimate failure modes were obtained to analyze the performance of resistance to low-velocity impact, as well as the impact energy absorption effect and failure mechanism, especially the structural damage characteristics of the 3DAWC subjected to the low-velocity impact of drop weight. By analyzing the obtained experimental results, it is found that the fabric reinforcement is the primary energy absorption component and the impact energy mainly propagates along the longitudinal direction of the yarns, especially the weft yarn system, which is arranged in a straight way. In addition, as the impact energy increases, the energy absorbed and dissipated by the composite increases simultaneously. This phenomenon is manifested in the severity of deformation and damage of the material, i.e., the amount of deformation and size of the damaged area.


2010 ◽  
Vol 452-453 ◽  
pp. 461-464
Author(s):  
Bai Tao Sun ◽  
Gui Xin Zhang

Based on the nearly 5,000 building samples investigated on site, damage characteristics of different types of building structures which located in different intensities regions are described and the reasons are analyzed in this paper. Three kinds of structural damage characteristics have been summarized as follows: 1) fortified masonry structures and unfortified ones; 2) masonry buildings with bottom frame; 3) reinforced concrete frame structures. The damage ratio of these three kinds of buildings in different intensities is obtained and the vulnerability has been compared. It provides the reference for those people who work for earthquake engineering to know the earthquake damage of different types of structures with fortified or unfortified. Also it provides important reference for revising seismic design code.


2013 ◽  
Vol 423-426 ◽  
pp. 1312-1316
Author(s):  
Ya Dong Yang ◽  
Xiang Dong Li ◽  
Xiao Ming Wang

In order to reveal the damage characteristics of internal explosion, the internal explosion of closed RC structure under incremental charges manner until structural damage are simulated by LS-DYNA code. The weight changes of charge influence on structure damage and distribution law of characteristic parameter of shockwave on the typical position are also discussed in this paper. The results show that, the distribution of shockwave overpressure on the walls under different weight of charge obey three kinds of linear laws as following: affected by one wall, two walls and three walls, respectively. The distributions of impulse on the walls under different weight of charge obey their distribution curve respectively when the structure is undestroyed, but the impulse will deviate from the distribution curve when the structure is destroyed. And the damage situation of RC structure under internal explosion is graded。


Author(s):  
W. Kunath ◽  
E. Zeitler ◽  
M. Kessel

The features of digital recording of a continuous series (movie) of singleelectron TV frames are reported. The technique is used to investigate structural changes in negatively stained glutamine synthetase molecules (GS) during electron irradiation and, as an ultimate goal, to look for the molecules' “undamaged” structure, say, after a 1 e/Å2 dose.The TV frame of fig. la shows an image of 5 glutamine synthetase molecules exposed to 1/150 e/Å2. Every single electron is recorded as a unit signal in a 256 ×256 field. The extremely low exposure of a single TV frame as dictated by the single-electron recording device including the electron microscope requires accumulation of 150 TV frames into one frame (fig. lb) thus achieving a reasonable compromise between the conflicting aspects of exposure time per frame of 3 sec. vs. object drift of less than 1 Å, and exposure per frame of 1 e/Å2 vs. rate of structural damage.


Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.


Author(s):  
R. C. Moretz ◽  
D. F. Parsons

Short lifetime or total absence of electron diffraction of ordered biological specimens is an indication that the specimen undergoes extensive molecular structural damage in the electron microscope. The specimen damage is due to the interaction of the electron beam (40-100 kV) with the specimen and the total removal of water from the structure by vacuum drying. The lower percentage of inelastic scattering at 1 MeV makes it possible to minimize the beam damage to the specimen. The elimination of vacuum drying by modification of the electron microscope is expected to allow more meaningful investigations of biological specimens at 100 kV until 1 MeV electron microscopes become more readily available. One modification, two-film microchambers, has been explored for both biological and non-biological studies.


Author(s):  
M. Pan

It has been known for many years that materials such as zeolites, polymers, and biological specimens have crystalline structures that are vulnerable to electron beam irradiation. This radiation damage severely restrains the use of high resolution electron microscopy (HREM). As a result, structural characterization of these materials using HREM techniques becomes difficult and challenging. The emergence of slow-scan CCD cameras in recent years has made it possible to record high resolution (∽2Å) structural images with low beam intensity before any apparent structural damage occurs. Among the many ideal properties of slow-scan CCD cameras, the low readout noise and digital recording allow for low-dose HREM to be carried out in an efficient and quantitative way. For example, the image quality (or resolution) can be readily evaluated on-line at the microscope and this information can then be used to optimize the operating conditions, thus ensuring that high quality images are recorded. Since slow-scan CCD cameras output (undistorted) digital data within the large dynamic range (103-104), they are ideal for quantitative electron diffraction and microscopy.


Author(s):  
Shubham N. Dadgal ◽  
Shrikant Solanke

In modern days for structures in coastal areas it has been observed that the premature structural failures are occurs due to corrosion of the reinforcements of the designed structural member. The corrosion causes the structural damage which in turn leads to reduction in the bearing capacity of the concerned structural members. The aim of this study was to study the effect of partial replacement of fly ash to minimize the corrosion effect. Beams were designed and corroded by using artificial method known accelerated corrosion method. The beams were then tested for flexural and bond strength. Also the weight loss of the reinforced bars was been determined using electrical resistivity method. The fly ash will replace by 10% and 15%.The strength will calculate at varying percentage of corrosion at 10% and 15%. Beams will cast at M25 grade concrete. The flexural strength will test by using UTM and the bond strength will calculate using pullout test.


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