Electric features of dislocations and electric force between dislocations

2020 ◽  
pp. 108128652096564
Author(s):  
Yuanjie Huang
Keyword(s):  
Electric Field ◽  
Dielectric Materials ◽  
Dislocation Motion ◽  
Vital Role ◽  
Dislocation Dynamics ◽  
Electric Force ◽  
Fundamental Knowledge ◽  
Large Dielectric Constant ◽  
Net Charges ◽  
First Time

Dislocations and dislocation dynamics are the cores of material plasticity. In this work, the electric features of dislocations were investigated theoretically. An intrinsic electric field around a single dislocation was revealed. In addition to the well-known Peach–Koehler force, it was established that an important intrinsic electric force exists between dislocations, which is uncovered here for the first time and has been neglected since the discovery of dislocations. The electric forces may be large and sometimes could exceed the Peach–Koehler force for metals and some dielectric materials with large dielectric constant. Therefore, the electric force is anticipated to play a vital role in dislocation dynamics and material plasticity. Moreover, an external electric field could exert an electric force on dislocations and a threshold electric field was subsequently discovered above which this force enables dislocations to glide. Interestingly, it was found that some dislocations move in one direction, but others move in reverse in an identical electric field, which is in agreement with experimental observations. Despite dislocation motion under an electric field, to one’s surprise, both edge and screw dislocations do not carry net charges by themselves, which may tackle the long-standing puzzle on the charges of dislocations. These findings may supply people with new fundamental knowledge on dislocations as well as dislocation dynamics, and may assist people in understanding related phenomena.

Mathematical model to predict the characteristics of polarization in dielectric materials: The concept of piezoelectrcity and electrostriction

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Mathematical Model ◽  
Electric Field ◽  
Lead Zirconate Titanate ◽  
Dielectric Material ◽  
Strain Curve ◽  
Dielectric Materials ◽  
Lead Zirconate ◽  
Simulation Software ◽  
Constitutive Law ◽  
Basic Material

Model was developed for the prediction of polarization characteristics in a dielectric material exhibiting piezoelectricity and electrostriction based on mathematical equations and MATLAB computer simulation software. The model was developed based on equations of polarization and piezoelectric constitutive law and the functional coefficient of Lead Zirconate Titanate (PZT) crystal material used was 2.3×10-6 m (thickness), the model further allows the input of basic material and calculation of parameters of applied voltage levels, applied stress, pressure, dielectric material properties and so on, to generate the polarization curve, strain curve and the expected deformation change in the material length charts. The mathematical model revealed that an application of 5 volts across the terminals of a 2.3×10-6 m thick dielectric material (PZT) predicted a 1.95×10-9 m change in length of the material, which indicates piezoelectric properties. Both polarization and electric field curve as well as strain and voltage curve were also generated and the result revealed a linear proportionality of the compared parameters, indicating a resultant increase in the electric field yields higher polarization of the dielectric materials atmosphere.

Electrostatic Dispensing of Dry Dielectric Materials

2001 ◽  
Vol 700 ◽  
Author(s):  
Malinda M. Tupper ◽  
Marjorie E. Chopinaud ◽  
Takamichi Ogawa ◽  
Michael J. Cima
Keyword(s):  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Dielectric Materials ◽  
Nonuniform Electric Field ◽  
Sodium Fluorescein ◽  
Silica Spheres ◽  
Electrode Geometry ◽  
Wide Range ◽  
Silica Beads

AbstractDispensing micron-scale dielectric materials can be achieved through the use of dielectrophoresis. Electrodes are designed to create a nonuniform electric field. This method is expected to be applicable for transfer of a wide range of dielectric powders as well as small, shaped components. Small, 150 μm diameter silica spheres, as well as sodium fluorescein powder have been dispensed by this method. Selecting the appropriate electrode geometry and electric field intensity controls the amount collected. As little as 1.0 μg of sodium fluorescein powder, and as much as 16 mg of silica beads have been collected, and repeatability within 10 % of the total amount dispensed has been achieved.

European Mail Armour

2021 ◽  
Author(s):  
Martijn A. Wijnhoven
Keyword(s):  
Early Modern ◽  
Middle Ages ◽  
Iron Age ◽  
Early Modern Period ◽  
Vital Role ◽  
Military Technology ◽  
Roman Army ◽  
Solid Foundation ◽  
First Time

Mail armour (commonly mislabelled 'chainmail') was used for more than two millennia on the battlefield. After its invention in the Iron Age, mail rapidly spread all over Europe and beyond. The Roman army, keen on new military technology, soon adopted mail armour and used it successfully for centuries. Its history did not stop there and mail played a vital role in warfare during the Middle Ages up to the Early Modern Period. Given its long history, one would think mail is a well-documented material, but that is not the case. For the first time, this books lays a solid foundation for the understanding of mail armour and its context through time. It applies a long-term multi-dimensional approach to extract a wealth of as yet untapped information from archaeological, iconographic and written sources. This is complemented with technical insights on the mail maker’s chaîne opératoire.

scholarly journals Atomically engineered interfaces yield extraordinary electrostriction

2021 ◽  
Author(s):  
Nini Pryds ◽  
Haiwu Zhang ◽  
Dae-Sung Park ◽  
Nicolas Gauquelin ◽  
Simone Santucci ◽  
...  
Keyword(s):  
Electric Field ◽  
Applied Electric Field ◽  
Dielectric Materials ◽  
Mechanical Deformation ◽  
Relaxor Ferroelectrics ◽  
Atomic Scale ◽  
Sensor Applications ◽  
Doped Ceo2 ◽  
Symmetry Breaking Phenomena ◽  
Electrostrictive Effect

Abstract Electrostriction is a property of all the dielectric materials where an applied electric field induces a mechanical deformation proportional to the square of the electric field. The magnitude of the effect is usually minuscule. However, recent discoveries of symmetry-breaking phenomena at interfaces opens up the possibility to extend the electrostrictive response to a broader family of dielectric materials.1,2 Here, we engineer the electrostrictive effect by epitaxially depositing alternating layers of Gd2O3-doped CeO2 and Er2O3-stabilized δ-Bi2O3 with atomically controlled interfaces on NdGaO3 substrates. We find that the electrostriction coefficient reaches 2.38×10-14 m2/V2, exceeding the best-known relaxor ferroelectrics by three orders of magnitude. Our atomic-scale calculations show that the extraordinary electrostriction coefficient is driven by the coherent strain imparted by the interfacial lattice mismatches. Thus, artificial heterostructures open a new avenue to design and manipulate electrostrictive materials and devices for nano/micro actuation and cutting-edge sensor applications.

scholarly journals First report on cyanobacterial flora from Masirah Island, Sultanate of Oman

Algologia ◽  
2020 ◽  
Vol 30 (4) ◽  
pp. 440-451
Author(s):  
M. Shamina ◽  
Keyword(s):  
Environmental Conditions ◽  
Food Industry ◽  
Vital Role ◽  
Taxonomic Composition ◽  
Climatic Conditions ◽  
Taxonomic Classification ◽  
Biofuel Production ◽  
Sultanate Of Oman ◽  
First Report ◽  
First Time

Cyanobacteria are organisms which play a vital role in various molecular and biotechnological aspects in food industry, agriculture, pharmaceuticals, neutraceuticals, biofuel production, etc., it is necessary to understand its adaptability to various environmental conditions. Furthermore it is equally important to discover new cyanobacterial taxa and with it occasional changes in taxonomic classification, thus the author set out to study cyanobacteria in extreme climatic conditions of desert, where temperatures are mostly above 45 oC. The taxonomic composition of cyanobacteria of Masirah Island, Sultanate of Oman, was studied for the first time. The studied samples were collected during the period of 2017–2019. The ten samples belonged to two orders: Oscillatoriales Schaffner and Synechococcales L.Hoffmann, Komárek & J.Kastovsky. All of them were filamentous non-heterocyst forms. Three species belonged to the genus Leptolyngbya Anagn. & Komárek, the genera Oscillatoria Vaucher ex Gomont and Lyngbya C.Agardh ex Gomont were represented by two species each, while the genera Pseudanabena Lauterborn, Planktolyngbya Anagn. & Komárek and Geitlerinema (Anagn. & Komárek) Anagn. were one species.

scholarly journals Передача крутящего момента проводящей частице с использованием силы Лоренца

2022 ◽  
Vol 56 (1) ◽  
pp. 76
Author(s):  
А.И. Грачев
Keyword(s):  
Dipole Moment ◽  
Electric Field ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Field Application ◽  
Conductive Particle ◽  
Particle Rotation ◽  
Dc Electric Field ◽  
First Time ◽  
Cylindrical Particles

In the paper the concept of conductive particle rotation in DC electric field with including the Lorentz force providing generation of electric dipole moment of the particle is for the first time discussed. Some models of the torque transfer to spherical and cylindrical particles based on of the Hall effect at usual geometry and with additional electric field application and also in the case of implementation of the photoelectromagnetic effect are presented.

scholarly journals Detection of isoprene traces in exhaled breath by using photonic crystals as a biomarker for chronic liver fibrosis disease

2021 ◽  
Author(s):  
Ahmed Mehaney ◽  
Hussein A. Elsayed ◽  
Ashour M. Ahmed
Keyword(s):  
Liver Fibrosis ◽  
Photonic Crystals ◽  
High Sensitivity ◽  
Dielectric Materials ◽  
Exhaled Breath ◽  
Air Cavity ◽  
One Dimensional ◽  
Sensor Structure ◽  
Volatile Organic ◽  
First Time

Abstract Detection of blood-carried volatile organic compounds (VOCs) existing in the exhaled breath of human is an attractive research point for noninvasive diagnosis of diseases. In this research, we introduce a novel application of photonic crystals (PCs) for the detection of isoprene traces in the exhaled breath as a biomarker for liver fibrosis. This idea is introduced for the first time according to the best of our knowledge. The proposed sensor structure is a one-dimensional (1D) PC constructed from a multilayer stack of two dielectric materials covered with an air cavity layer filled with the dry exhaled breath (DEB) and a thin metallic layer of Au is attached on the top surface. Hence, the proposed sensor is configured as, [prism/Au/air cavity/(GaN/SiO2)10]. The transfer matrix method and the Drude model are adopted to calculate the numerical simulations and reflection spectra of the design. The essential key for sensing isoprene levels is the resonant optical Tamm plasmon (TP) states within the photonic bandgap. The obtained numerical results are promising such as high sensitivity (S) of 0.321 nm/ppm or 278720 nm/RIU. This technique can be reducing the risk of infection during the taking of blood samples by syringe. Also, it can prevent the pain of patients. Finally, this work opens the door for the detection of many diseases by analyzing the breaths of patients based on photonic crystals.

scholarly journals PD-1 Suppresses the Osteogenic and Odontogenic Differentiation of Stem Cells From Dental Apical Papilla via Targeting SHP2/NF-κB axis

2021 ◽  
Author(s):  
Na Li ◽  
Zehan Li ◽  
Lin Fu ◽  
Ming Yan ◽  
Yanqiu Wang ◽  
...  
Keyword(s):  
Vital Role ◽  
Cell Counting ◽  
Alizarin Red ◽  
Odontogenic Differentiation ◽  
Root Dentin ◽  
Apical Papilla ◽  
Effect Of Pd ◽  
First Time ◽  
The Relationship

Abstract BackgroundStem cells from the apical papilla (SCAPs) are important for tooth root development and regeneration of root dentin. Here, we examined the expression of programmed cell death protein-1 (PD-1) in SCAPs and investigated the effect of PD-1 on odontogenic and osteogenic differentiation and the relationship between PD-1 and cell differentiation and SHP2/NF-κB signals.MethodsSCAPs were obtained culture in the related medium. The proliferation ability was evaluated by cell counting kit 8 and 5‐ethynyl‐20‐deoxyuridine (EdU) assay. Alkaline phosphatase (ALP) activity assay, ALP staining, western blot, real-time RT-PCR, Alizarin Red S staining, and immunofluorescence staining were performed to explore the osteo/odontogenic potential and the involvement of SHP2/NF-κB pathways. Besides, we transplanted SCAPs component into mouse calvaria defects to evaluate osteogenesis in vivo. ResultsWe found that human SCAPs expressed PD-1 for the first time. PD-1 knockdown enhanced the osteo/odontogenic differentiation of SCAPs by suppressing SHP2 pathway and activating NF-κB pathway. Overexpression of PD-1 inhibited the osteogenesis and odontogenesis of SCAPs via activation of SHP2 signal and inhibition of NF-κB pathway. ConclusionPD-1 activated SHP2 signal to block NF-κB signal and then played a vital role in osteo/odontogenic differentiation of SCAPs.

scholarly journals 2 Dimensional Dislocation Dynamics – A New Technique for the Simulation of Deformation Microtextures

1997 ◽  
Vol 28 (3-4) ◽  
pp. 167-179
Author(s):  
F. Roters ◽  
D. Raabe
Keyword(s):  
Cold Deformation ◽  
Dislocation Motion ◽  
Dislocation Dynamics ◽  
New Technique ◽  
Linear Elastic ◽  
Straight Line ◽  
Simulation Step ◽  
Local Stresses ◽  
A New Technique ◽  
Edge Dislocations

A new technique for the simulation of microtexture evolution during cold deformation which is based on 2 dimensional (2D) dislocation dynamics is presented. In the simulation all involved dislocations are regarded as infinite straight line detects which are embedded in an otherwise isotropic linear elastic medium. As the model is 2D only edge dislocations are considered.In the first simulation step the net local stresses are derived and used to calculate the resulting dislocation motion. Dislocation multiplication, annihilation and reactions are taken into account. Thermal activation is included. In the second step the local misorientations arising from the dislocation distribution are calculated.This method shows in microscopic detail how misorientations are generated and distributed within grains during plastic deformation.

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