- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Effect of large-scale domain switching on intensity factors for a crack in 3D ferroelectric single crystals using the I-integral method
摘要： Due to their intrinsic brittleness, ferroelectric materials are prone to fracture under extreme electromechanical operational loads. The fracture of ferroelectric materials is usually accompanied by large-scale domain switching. This paper develops the interaction integral (I-integral) method for a crack in three-dimensional ferroelectrics through applying a virtual load increment to the current state. Unlike the widely-used switching-toughening model, the I-integral is not restricted to small scale switching. Due to designable choice of the virtual load increment, the I-integral allows to decouple the intensity factors of different fracture modes. The local intensity factors along the curved crack front can be directly extracted, since the I-integral is independent of integration volume. With these merits, the I-integral method is a very promising technique in fracture analysis of ferroelectrics under large-scale domain switching. Moreover, the I-integral method is used in combination with the phase field model to simulate a tensile test of nanoscale PbTiO3 ferroelectric single crystal with a semi-circular surface crack. Results show that various patterns of polarization pairs appear as soon as the applied load is increased beyond a critical value. The stable domain structures are divided into two layers by the plane where the crack is located and in each layers several polarization vortices formed eventually. Apart from the geometry and loading conditions, the position where the crack front is located with respect to the polarization vortex is a key factor affecting the switching-induced change of the stress intensity factor.
关键词： crack,interaction integral (I-integral),large-scale domain switching,phase field model,ferroelectric,intensity factor
更新于2025-09-10 09:29:36
-
Analysis of interaction between sulfated polysaccharides and HIV oligopeptides by surface plasmon resonance
摘要： This study aims to quantitatively investigate the interaction between sulfated polysaccharides with potent anti-HIV activity, dextran and curdlan sulfates with negatively charged sulfate groups, and poly-L-lysine as a model protein and oligopeptides from a HIV surface glycoprotein gp120 with positively charged amino acids using surface plasmon resonance (SPR) and dynamic light scattering (DLS) to elucidate the anti-HIV mechanism of sulfated polysaccharides. The apparent association- (ka) and dissociation rate (kd) constants of dextran and curdlan sulfates against poly-L-lysine were ka=6.92×104?2.17×106 1/Ms and kd=4.29×10-5? 2.22×10-4 1/s; these kinetic constants were dependent on the molecular weights and degree of sulfation of sulfated polysaccharides. For interaction, the three oligopeptides from the HIV gp120 were peptide A 297TRPNNNTRKRIRIQRGPGRA316 with several lysine (K) and arginine (R) in the V3 loop region, peptide B 493PLGVAPTKAKRRVVQREKR511 with several K and R in the C-terminus region, and oligopeptide C 362KQSSGGDPEIVTHSFNCGG380 with little basic amino acids in the CD4 binding domain. Sulfated polysaccharides exhibited strong interaction against oligopeptides A and B, (ka=5.48×104?2.96×106 1/Ms and kd=1.74×10-4?6.24×10-3 1/s), no interaction was noted against oligopeptide C. Moreover, the particle size and zeta potential by DLS indicated the interaction between sulfated polysaccharides and oligopeptides A and B, suggesting the anti-HIV mechanism of sulfated polysaccharides to be the electrostatic interaction of negatively charged sulfated polysaccharides and HIV at the positively charged amino acid regions.
关键词： Model peptide,Interaction,SPR,Sulfated polysaccharide,HIV surface oligopeptide
更新于2025-09-10 09:29:36
-
Magnetic field effect on polaron recombination in conjugated polymers
摘要： By using the one-dimensional tight-binding model, we theoretically investigate the effect of magnetic field on the collision of the oppositely charged polarons with their spin antiparallel in cis-polyacetylene. We adopt the non-adiabatic approach to simulate the dynamical evolution of polaron spin. Under the effect of electric field with a moderate strength, the polarons initially localized at the chain-end of polyacetylene move towards each other. During the collision process, an obvious spin precession is obtained, and the precession period is found to be inversely proportional to the strength of magnetic field. While after including electron-electron interaction in form of Hubbard model, the period is no longer constant. With the decrease of distance between the oppositely charged polarons, the precession of their spin slows down. We also find that there is a critical value of electron-electron interaction strength, over which the spin precession of polaron disappears. In addition, we demonstrate that under the effect of magnetic field, the polarons could recombine or pass through each other to form the singlet exciton, rather than be dissociated after collision between them with the strong electron-electron interaction, and then the electroluminescence efficiency of organic optoelectronic devices is improved.
关键词： polaron,conjugated polymer,Zeeman effect,electron-electron interaction,spin precession,magneto-electroluminescence
更新于2025-09-10 09:29:36
-
Rose Bengal Incorporated to α-Cyclodextrin Microparticles for Photodynamic Therapy against the cariogenic microorganism Streptococcus mutans
摘要： Rose Bengal@α-cyclodextrin (RB@α-CD) microparticles (μPs) were prepared and the RB inclusion in α-CD was experimentally demonstrated through infrared, UV-VIS absorption spectroscopy and cyclic voltammetry. The RB inclusion in α-CD was theoretically investigated using classical molecular mechanics calculations, the simulation results showing that RB can be included in both the narrow and wide apertures of the α-cyclodextrin ring with configurations exhibiting average binding energies of about 27 kcal.mol-1. The prepared RB@α-CD microparticles were characterized through Scanning Electron Microscopy (SEM) and it was demonstrated that they are highly efficient in the photodynamic therapy against a Streptococcus mutans (the main bacteria of cariogenic dental plaque) suspension, as a concentration of RB@α-CD μPs 10 times smaller than the usual concentration of pure RB is still capable to produce significant antibacterial activity.
关键词： antibacterial activity,molecular interaction simulations,Rose Bengal,photodynamic therapy,α-cyclodextrin microparticles
更新于2025-09-10 09:29:36
-
All-optical generation and ultrafast tuning of non-linear spin Hall current
摘要： Spin Hall effect, one of the cornerstones in spintronics refers to the emergence of an imbalance in the spin density transverse to a charge flow in a sample under voltage bias. This study points to a novel way for an ultrafast generation and tuning of a unidirectional nonlinear spin Hall current by means of subpicosecond laser pulses of optical vortices. When interacting with matter, the optical orbital angular momentum (OAM) carried by the vortex and quantified by its topological charge is transferred to the charge carriers. The residual spin-orbital coupling in the sample together with confinement effects allow exploiting the absorbed optical OAM for spatio-temporally controlling the spin channels. Both the non-linear spin Hall current and the dynamical spin Hall angle increase for a higher optical topological charge. The reason is the transfer of a higher amount of OAM and the enhancement of the effective spin-orbit interaction strength. No bias voltage is needed. We demonstrate that the spin Hall current can be all-optically generated in an open circuit geometry for ring-structured samples. These results follow from a full-fledged propagation of the spin-dependent quantum dynamics on a time-space grid coupled to the phononic environment. The findings point to a versatile and controllable tool for the ultrafast generation of spin accumulations with a variety of applications such as a source for ultrafast spin transfer torque and charge and spin current pulse emitter.
关键词： optical vortices,orbital angular momentum,Spin Hall effect,quantum rings,spin-orbit interaction,spintronics
更新于2025-09-10 09:29:36
-
High-speed Fizeau interferometry for film topography measurement during spray film interaction
摘要： This work presents a novel high-speed interferometric thickness measurement system for thin films (1 μm-23 μm). The system is based on a Fizeau-interferometer and combines a high-speed camera for 2-D topographic fringe images with a spectrally resolved white light interferometer. The aim of this combination is to overcome the ambiguities of the phase demodulation process during fringe pattern analysis. The system is able to measure spatially and temporally resolved film thickness distributions during fast processes. The measurement error of the system is around 5% compared to a commercial 0-D interferometer. First, the results during a diesel spray impingement onto a predefined diesel film are shown, and at the impingement point, an increase in a fluid volume of 24.3% can be seen.
关键词： interferometric thickness measurement,High-speed Fizeau interferometry,thin films,spray film interaction,film topography measurement
更新于2025-09-10 09:29:36
-
Modification of Glial Attachment by Surface Nanostructuring of SU-8 Thin Films
摘要： Various methods are currently under development to enhance the biocompatibility of neural electrodes and to minimize the reactive gliosis around the implant surface. As cells in their native microenvironment interact with 3D nanoscale topographies of the extracellular matrix, physical modification of implant surfaces may provide an alternative solution to the negative tissue response by imitating the structure of the extracellular matrix, and therefore affecting the attachment and behavior of neurons and glial cells. The attachment of primary mouse astrocytes on nanostructured SU8 polymer surfaces fabricated by e-beam lithography was investigated in our study. We found that attachment of primary mouse astrocytes on silicon-SU8 surfaces is strongly influenced by the surface topography.
关键词： SU-8,cell attachment,nanostructuring,cell-surface interaction
更新于2025-09-10 09:29:36
-
Plasma spatial distribution manipulation and electrical property enhancement through plasma coupling effect
摘要： Plasma pattern transition in a symmetric hybrid structure cavity device at micrometer scale is researched through microplasma interaction in intervening microchannel between adjacent cavities while manipulating electric field strength. Plasma distribution reconfiguration in central (objective) cavity is observed when sidearm (donor) cavities are ignited. As long as coupling effect occurred by modulating the electric field strength in the sidearm cavities, stable plasma pattern transition in objective cavity is obtained, exhibiting plasma pattern split from one circular spot (initial pattern) to two small circular spots (transited pattern), along with plasma peak emission intensity displacement over 100 μm to its equilibrium position. The shape of transited plasma patterns are depending on the coupling effect from sidearm cavities. The two circular spots unsymmetrically distributed if either donor cavity is ignited, and the ratio of average emission intensity between the two plasma spots is over 30%, however, which is less than 4% if coupling symmetrically occurred. The electrical and optical properties of central microplasma are also modulated, that the breakthrough voltage is decreased by 22% and emission intensity is improved by ～30%, by means of plasma coupling. The microplasma pattern formation at micrometre scale and manipulation of the electrical properties in microscale cavity implies significant value in the application of plasma transistor and signal processing.
关键词： microscale cavity,plasma pattern transition,plasma coupling effect,electric field strength,microplasma interaction
更新于2025-09-10 09:29:36
-
Interacting Automultiscopic 3D with Haptic Paint Brush in Immersive Room
摘要： In this work, we propose an interactive artwork system with automultiscopic 3D and haptic paint brush in an immersive room. Our system consists of an 81-view automultiscopic display, a handheld haptic paint brush, and a large-scale color palette station in a CAVE-like cubic room filled with the visual scene of the artwork. The 81-view rendering and multiplexing technology is applied by setting up the virtual cameras in the off-axis layout. The haptic paint brush is designed and implemented using a 2D array of multiple piezoelectric actuators. It provides the tactile feedback of spatial distance information between a virtual brush and a distal 3D object displayed on the automultiscopic display for precise control of the brush when it is interacting with automultiscopic 3D. We demonstrate a proof-of-concept system that integrates a classic artwork into an innovative interactive system using novel multimedia and interaction technologies, and evaluate our system using the handheld haptic brush for its performance and usability to enhance the user experiences.
关键词： haptic feedback,room-based VR,3D haptic interaction,automultiscopic 3D interaction,Immersive environment
更新于2025-09-09 09:28:46
-
[ASME 2018 26th International Conference on Nuclear Engineering - London, England (Sunday 22 July 2018)] Volume 9: Student Paper Competition - Modelling of X-Ray Radioscopy for Phase Topology Estimation During Corium Sodium Interaction
摘要： In case of a severe accident scenario in a Sodium cooled Fast Reactor (SFR) such as the ASTRID demonstrator, the fuel might melt and interact with the coolant i.e. liquid sodium. This molten Fuel Coolant Interaction (FCI) can generate an energetic vapor explosion that can jeopardize the reactor structures. The yield of the vapor explosion is strongly dependent on the local distribution of the fragmented melt with respect to the local vapor fractions. The medium is composed of three phases, i.e. corium, liquid sodium and vapor sodium. Thus, a study of the three phase distribution within the system is a key to understand the extent of the explosion. PLINIUS-2, the future large mass experimental platform of CEA Cadarache will be dedicated to conducting experiments to understand the behavior of prototypic corium in case of severe accidents. In order to study these interactions, a high energy X-ray imaging system is being developed. This system consists of a 15 MeV Linear accelerator producing high energy X-rays with significantly high flux, which are attenuated as it passes through the highly dense test section. The transmitted radiation is detected and re-emitted as visible light by the GADOX screen coupled to the CMOS camera. Using this system to study the interaction between corium and sodium is particularly challenging due to the small corium particulates of the size of the order of 1 mm. The qualification of the foreseen radioscopy system on the visualization of such an interaction requires the development of physical phantoms. This paper presents the preliminary simulations of expected images of corium fragments in sodium, vapor bubbles and vapor film around the fragments. The simulations are carried out using a CEA Cadarache in-house tool MODHERATO, which produces radiographic images in satisfactory agreement with the real time imaging. The simulation of particles is based on the knowledge of interaction phenomenology gained from past experiments and on the statistical analysis of the size of corium particles formed. The models which, according to MODHERATO results, qualify to be detected and resolved, help manufacturing physical phantoms to conduct the experiments.
关键词： Sodium cooled Fast Reactor,Fuel Coolant Interaction,corium-sodium interaction,MODHERATO,X-ray imaging
更新于2025-09-09 09:28:46