Understanding the Radiation Resistance Mechanisms of Nanocrystalline Metals from Atomistic Simulation

Metallic materials produce various structural defects in the radiation environment, resulting in serious degradation of material properties. An important way to improve the radiation-resistant ability of materials is to give the microstructure of materials a self-healing ability, to eliminate the structural defects. The research and development of new radiation-resistant materials with excellent self-healing ability, based on defects control, is one of the hot topics in materials science. Compared with conventional coarse-grained materials, nanocrystalline metals with a high density of grain boundary (GB) show a higher ability to resist radiation damage. However, the mechanism of GB’s absorption of structural defects under radiation is still unclear, and how to take advantage of the GB properties to improve the radiation resistance of metallic materials remains to be further investigated. In recent decades, atomistic simulation has been widely used to study the radiation responses of different metals and their underlying mechanisms. This paper briefly reviews the progress in studying radiation resistance mechanisms of nanocrystalline metals by employing computational simulation at the atomic scale.

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Modeling the Layer-by-Layer Growth of HKUST-1 Metal-Organic Framework Thin Films

Nanomaterials ◽

10.3390/nano11071631 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1631

Author(s):

Qiang Zhang ◽

Yohanes Pramudya ◽

Wolfgang Wenzel ◽

Christof Wöll

Keyword(s):

Thin Films ◽

Surface Roughness ◽

Deposition Rate ◽

Layer Growth ◽

Coarse Grained ◽

Structural Defects ◽

Effect Of Temperature ◽

Layer By Layer ◽

Reactant Concentration ◽

Metal Organic

Metal organic frameworks have emerged as an important new class of materials with many applications, such as sensing, gas separation, drug delivery. In many cases, their performance is limited by structural defects, including vacancies and domain boundaries. In the case of MOF thin films, surface roughness can also have a pronounced influence on MOF-based device properties. Presently, there is little systematic knowledge about optimal growth conditions with regard to optimal morphologies for specific applications. In this work, we simulate the layer-by-layer (LbL) growth of the HKUST-1 MOF as a function of temperature and reactant concentration using a coarse-grained model that permits detailed insights into the growth mechanism. This model helps to understand the morphological features of HKUST-1 grown under different conditions and can be used to predict and optimize the temperature for the purpose of controlling the crystal quality and yield. It was found that reactant concentration affects the mass deposition rate, while its effect on the crystallinity of the generated HKUST-1 film is less pronounced. In addition, the effect of temperature on the surface roughness of the film can be divided into three regimes. Temperatures in the range from 10 to 129 °C allow better control of surface roughness and film thickness, while film growth in the range of 129 to 182 °C is characterized by a lower mass deposition rate per cycle and rougher surfaces. Finally, for T larger than 182 °C, the film grows slower, but in a smooth fashion. Furthermore, the potential effect of temperature on the crystallinity of LbL-grown HKUST-1 was quantified. To obtain high crystallinity, the operating temperature should preferably not exceed 57 °C, with an optimum around 28 °C, which agrees with experimental observations.

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Genetic studies of strain Bs8 ofEscherichia coli

Genetics Research ◽

10.1017/s0016672300011617 ◽

1968 ◽

Vol 12 (1) ◽

pp. 55-63 ◽

Cited By ~ 5

Author(s):

John Donch ◽

Joseph Greenberg

Keyword(s):

Radiation Resistance ◽

Resistant Strain ◽

Double Mutant ◽

Ofescherichia Coli ◽

Genetic Studies ◽

Radiation Resistant ◽

K 12

Strain Bs8 is a u.v.-sensitive derivative of strain B. It is unable to reactivate irradiated phage (HCR) and it cannot be induced to form filaments. The HCR properties are attributable to a gene,uvr8, cotransducible withgal+. Whenuvr8was transduced into radiation-resistant strain B/r the resulting phenotype was indistinguishable from Bs8. When transduced into alonK-12 strain the phenotype was more sensitive than Bs8, filament-inducible and mucoid. When PI-Bs8 was used to transduceproC+into aproCK-12 strain, 4% of the transductants werelon, i.e. about as u.v.-sensitive as Ion K-12, filament-inducible and mucoid. Radiation resistance could not be transduced from strain Bs8 withproC+into aproClon K-12 derivative. Nor did Bs8 show any evidence of being exr. Bs8 is a double mutant of strain B, behaving as though it were HCE, in a B/r background.

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PO-115 Radiation resistance mechanisms of breast cancer cells

10.1136/esmoopen-2018-eacr25.640 ◽

2018 ◽

Author(s):

G Negro ◽

B Aschenbrenner ◽

S Skvortsov ◽

C Jimenez ◽

U Ganswindt ◽

...

Keyword(s):

Breast Cancer ◽

Cancer Cells ◽

Radiation Resistance ◽

Breast Cancer Cells ◽

Resistance Mechanisms

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Swap-Driven Self-Adhesion and Healing of Vitrimers

Coatings ◽

10.3390/coatings9020114 ◽

2019 ◽

Vol 9 (2) ◽

pp. 114 ◽

Cited By ~ 4

Author(s):

Simone Ciarella ◽

Wouter Ellenbroek

Keyword(s):

Molecular Dynamics ◽

Relaxation Time ◽

Stress Relaxation ◽

Healing Process ◽

Star Polymers ◽

Coarse Grained ◽

Self Healing ◽

Central Question ◽

Trade Off ◽

Dynamics Simulations

Vitrimers are covalent network materials, comparable in structure to classical thermosets. Unlike normal thermosets, they possess a chemical bond swap mechanism that makes their structure dynamic and suitable for activated welding and even autonomous self-healing. The central question in designing such materials is the trade-off between autonomy and material stability: the swap mechanism facilitates the healing, but it also facilitates creep, which makes the perfectly stable self-healing solid a hard goal to reach. Here, we address this question for the case of self-healing vitrimers made from star polymers. Using coarse-grained molecular dynamics simulations, we studied the adhesion of two vitrimer samples and found that they bond together on timescales that are much shorter than the stress relaxation time. We showed that the swap mechanism allows the star polymers to diffuse through the material through coordinated swap events, but the healing process is much faster and does not depend on this mobility.

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The Influence of Neodymium Element on the Crater Structure Formed on Al-17.5Si Alloy Surface Processed by High-Current Pulsed Electron Beam

Coatings ◽

10.3390/coatings10100922 ◽

2020 ◽

Vol 10 (10) ◽

pp. 922

Author(s):

Kui Li ◽

Bo Gao ◽

Ning Xu ◽

Yue Sun ◽

Vladimir Viktorovich Denisov ◽

...

Keyword(s):

Electron Microscopy ◽

Electron Beam ◽

Primary Silicon ◽

Structural Defects ◽

Metallic Materials ◽

High Current ◽

Metallic Material ◽

Pulsed Electron Beam ◽

Electron Microscopy Analysis ◽

Microscopy Analysis

The effect of neodymium element on the elimination of crater structures on the surface of Al-17.5Si metallic materials processed by high-current pulsed electron beam was investigated in this study. Field emission scanning electron microscopy analysis indicated that the grain sizes of Al-17.5Si metallic materials were reduced and craters were removed from surfaces of the processed Al-17.5Si metallic material after addition of Nd. This can be attributed to the efficient transfer of heat accumulated in rich-silicon (primary silicon) areas without the eruption of a primary silicon phase if the size of primary silicon grains are small. The X-ray diffraction analysis indicates that all diffraction peaks are broadened because of the presence of structural defects, grain refinement and stress state. Electron probe micro-analyzer analysis demonstrated that Al and Nd were evenly distributed on the surface of the treated alloy, which could be attributed to the diffusion of the element. Transmission electron microscopy analysis showed that nano-Al and nano-Si cellular textures were generated during the treated process. The formation of these structures can be attributed to rapid heating and cooling effects by the treatment. Finally, electrochemical tests revealed that the corrosion current density of Al-17.5Si metallic materials (with Nd, 0.3 wt.%.) surface decreased by three orders of magnitude compared with that of the processed Al-17.5Si metallic material surfaces (without Nd). This can be attributed to the elimination of craters and grain refining.

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Abstract 522: Role and regulation of Aurora A in radiation resistance mechanisms in glioblastoma

10.1158/1538-7445.am2016-522 ◽

2016 ◽

Author(s):

Brinda Ramasubramanian ◽

Kamalakannan Palanichamy ◽

Disha Patel ◽

Saikh Jaharul Haque ◽

Arnab Chakravarti

Keyword(s):

Radiation Resistance ◽

Resistance Mechanisms ◽

Aurora A

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Development of Self-Healable Organic/Inorganic Hybrid Materials Containing a Biobased Copolymer via Diels–Alder Chemistry and Their Application in Electromagnetic Interference Shielding

Polymers ◽

10.3390/polym11111755 ◽

2019 ◽

Vol 11 (11) ◽

pp. 1755

Author(s):

Yi-Huan Lee ◽

Wen-Chi Ko ◽

Yan-Nian Zhuang ◽

Lu-Ying Wang ◽

Tao-Wei Yu ◽

...

Keyword(s):

Hybrid Materials ◽

Hybrid System ◽

Electromagnetic Interference ◽

Diels Alder ◽

Structural Defects ◽

Material System ◽

Self Healing ◽

Electromagnetic Interference Shielding ◽

Band Frequency ◽

Inorganic Hybrid

In this study, a novel biobased poly(ethylene brassylate)-poly(furfuryl glycidyl ether) copolymer (PEBF) copolymer was synthesized and applied as a structure-directing template to incorporate graphene and 1,1′-(methylenedi-4,1-phenylene)bismaleimide (BMI) to fabricate a series of self-healing organic/inorganic hybrid materials. This ternary material system provided different types of diene/dienophile pairs from the furan/maleimide, graphene/furan, and graphene/maleimide combinations to build a crosslinked network via multiple Diels–Alder (DA) reactions and synergistically co-assembled graphene sheets into the polymeric matrix with a uniform dispersibility. The PEBF/graphene/BMI hybrid system possessed an efficient self-repairability for healing structural defects and an electromagnetic interference shielding ability in the Ku-band frequency range. We believe that the development of the biobased self-healing hybrid system provides a promising direction for the creation of a new class of materials with the advantages of environmental friendliness as well as durability, and shows potential for use in advanced electromagnetic applications.

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