Article
Materials Science, Multidisciplinary
Zhengwu Fang, Boyang Li, Susheng Tan, Scott Mao, Guofeng Wang
Summary: This study reveals the atomic-scale migration behavior of a typical shear-coupled mixed tilt-twist GB (MGB) in Au nanocrystals. Two distinct migration patterns were observed, mediated by GB disconnections with different crystallographic parameters. The study also found that excess GB sliding and GB plane reorientation accommodate the GB migration. These findings provide valuable insights into optimizing the ductility of metallic nanocrystals through controlling GB migration.
Article
Materials Science, Multidisciplinary
Xiaojiang Long, Weihao Wang, Wanli Zhang, Guangzhao Wang, Wenxi Zhao
Summary: In this study, shock-induced sliding behavior of (0 0 1) twist grain boundaries in Cu bicrystal was investigated using molecular dynamics simulations. The sliding of grain boundaries is found to be produced by transverse particle motion in the constituent grains and is resisted by the viscosity of the grain boundaries. The magnitude of sliding is determined by the angle between the [1 0 0] direction in the grain and the shock direction.
RESULTS IN PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Eisuke Miyoshi, Munekazu Ohno, Yasushi Shibuta, Akinori Yamanaka, Tomohiro Takaki
Summary: By utilizing a novel framework, this study proposes a method to measure anisotropic grain boundary energy and mobility from observations of grain growth. Numerical tests demonstrate that the method accurately estimates these properties even under conditions of strong anisotropy and grain rotation. The results show the potential of this method in extracting a large dataset of grain boundary properties from actual grain growth observations.
MATERIALS & DESIGN
(2021)
Article
Nanoscience & Nanotechnology
Xiang Liu, Mei Wu, Ke Qu, Peng Gao, Wenbo Mi
Summary: In this study, artificial grain boundaries were introduced in Fe3O4 films to manipulate the magnetic and transport properties of materials. It was found that the in-plane rotation of Fe3O4 lattice on bicrystal substrates altered the magnetization processes, with Fe3O4 bicrystal films with larger tilt angles exhibiting strong in-plane magnetic anisotropy.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Materials Science, Multidisciplinary
Can Cui, Qiang Yu, Wei Wang, Weiwei Xu, Lijie Chen
Summary: This paper investigates the mechanical properties of different twist grain boundary structures in copper through molecular dynamics simulations, with a focus on the <111> Sigma 3 GB structure which exhibits the highest tensile strength and lowest grain boundary energy. The study also reveals that the tensile strength increases with the twist angle for <001> and <101> twist GB structures, but has limited influence on almost all <111> twist GB structures, except for Sigma 3.
Article
Materials Science, Multidisciplinary
Xuefeng Liao, Weiwei Zeng, Lizhong Zhao, Qing Zhou, Jiayi He, Wei Li, Xiangyi Liu, Hongya Yu, Xiaolian Liu, Haoyang Jia, Jean-Marc Greneche, Xuefeng Zhang, Zhongwu Liu
Summary: This article introduces a new method to improve the magnetic properties of rare earth-iron-boron magnets. By using a two-step grain boundary diffusion process, a magnet with excellent magnetic properties was obtained. The formation of RE-rich grain boundary layer through doping and diffusion was found to contribute to the enhancement of coercivity, supported by differential scanning calorimetry and transmission electron microscopy.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
B. Bian, S. Taheriniya, G. Mohan Muralikrishna, A. Godha, S. K. Makineni, S. Sankaran, B. B. Straumal, Y. Du, G. Wilde, S. V. Divinski
Summary: Kinetic and structural changes induced by Bi alloying in dilute Ni-Bi alloys were investigated, focusing on grain boundary phase transitions. The grain boundary diffusion of Ni in the Ni-Bi alloys was measured across single and two-phase regions of the bulk phase diagram. The results showed that the Ni grain boundary diffusion rates were dependent on the Bi concentration and were influenced by Bi segregation and multi-layer Bi segregation along the grain boundaries. The presence of a liquid layer of Bi at the grain boundaries resulted in the highest Ni diffusivity. Additionally, structural transitions between different grain boundary phases were found to have a significant impact on the grain boundary diffusion rates.
Article
Chemistry, Physical
Mouna Derbali, Taoufik Soltani, Ahlem Guesmi, Naoufel Ben Hamadi, Erwann Jeanneau, Yves Chevalier
Summary: Two series of hydrogen-bonded liquid crystals were investigated, consisting of 4-alkoxy-2,3-difluorobenzoic acids with different alkoxy chain lengths and mixtures of these acids with 4-octyloxybenzoic acid. The phase behavior of these compounds was studied, revealing a decrease in transition temperatures and order parameter with increasing alkoxy chain length. The electro-optic properties of the mixtures also showed changes with chain length.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Nanoscience & Nanotechnology
Ashwini Reddy Nallayagari, Emanuela Sgreccia, Luca Pasquini, Marco Sette, Philippe Knauth, Maria Luisa Di Vona
Summary: Composite electrocatalytic electrodes made from B-N co-doped carbon quantum dots and various anion exchange ionomers are studied for the oxygen reduction reaction in alkaline solutions. The quantity and positions of dopants in the carbon quantum dots are found to be crucial for the electrocatalytic performance, and ionomers with long side chains exhibit the highest activity.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
Carolina Baruffi, Christian Brandl
Summary: High radiation damage resistance is increasingly important for functional materials in harsh environments. Diamond cubic carbon, with its high radiation damage resistance, is a unique material that can be used in radiation environments. The interaction between point defects and interfaces, such as grain boundaries, increases resistance to radiation damage. Grain boundaries act as sinks for point defects and can be used to control the segregation of point defects, thereby preventing material degradation.
Article
Chemistry, Physical
Tian Hong Zhou, Hui-Dong Qian, Jung Tae Lim, Han-Kuk Jeon, Chul-Jin Choi, Young-Rae Cho, Jihoon Park
Summary: We have successfully fabricated high-purity high-density Sm(Fe0.8Co0.2)(12-2x)TixVx (0.6 ≤ x ≤ 1.0) bulk magnets through the bulking of amorphous powder and subsequent annealing process. The addition of Cu-Ga additive enhanced the grain boundary structure and improved the magnetic properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Liana Lucchetti, Giovanni Nava, Raouf Barboza, Fabrizio Ciciulla, Tommaso Bellini
Summary: By coupling optical forces with the nematic director, we were able to measure the splay and twist elastic constants and viscosities of CCN47. In the nematic phase far from the transition, it was found that the splay elastic constant is larger than the twist constant and has a smaller viscosity.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Materials Science, Multidisciplinary
M. Praveen Kumar, Jakub Karcz, Przemyslaw Kula, Surajit Dhara
Summary: The twist-bend nematic liquid crystal shows three dynamic regimes: region I where stress is proportional to the square root of shear rate, region II with stress showing a near plateau, and region III where stress is proportional to shear rate. The transition from region I to II is continuous, while the transition from II to III is discontinuous with hysteresis. In region II, dynamic stress fluctuations are observed under steady shear, demonstrating spatiotemporal dynamics similar to theoretical predictions in sheared nematogenic fluids.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Y. . L. Huang, Q. Rao, Q. Feng, Z. J. Wu, Y. F. Yao, Y. H. Hou, W. Li, J. M. Luo
Summary: Grain boundary diffusion (GBD) is used to improve the coercivity of Nd-Fe-B magnets without reducing the remanence and maximum magnetic energy product. Dy30Cu70 alloy is used as the diffusion source to enhance the coercivity. The diffusion of Dy and Cu leads to the formation of (Nd, Dy)2Fe14B shell in the matrix phase, inhibiting the nucleation of reversed magnetic domain and increasing the magnetic isolation effect between matrix phases. The optimization of the intergranular phase and the formation of (Dy, Nd)2Fe14B shell contribute to the significant improvement of coercivity. Additionally, the diffusion of DyCu alloy improves thermal stability and corrosion resistance.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Chemistry, Multidisciplinary
Wei Zhang, Xuefeng Lu, Junqiang Ren, Junchen Li, Hongtao Xue, Fuling Tang, Xin Guo
Summary: Solute element segregation behavior significantly affects the mechanical properties and deformation mechanism of nanocrystals. By using molecular dynamics, we investigated the effect of segregation structure on the deformation mechanism of NiCoAl nanocrystalline. The results reveal that complete segregation of Al within the grain leads to poor grain boundary stability and ineffective hindrance of dislocation movement, resulting in inferior mechanical properties. However, when 4% of Al transitions to the grain boundary, the stability improves significantly, generating lamination structures that effectively strengthen the nanocrystals.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Chemistry, Multidisciplinary
Vladimira Novotna, Sergey Stulov, Martin Cigl, Vera Hamplova, Ewa Gorecka, Damian Pociecha
Article
Chemistry, Multidisciplinary
Martin Cigl, Frantisek Hampl, Jiri Svoboda, Natalia Podoliak, Sergei Stulov, Michal Kohout, Vladimira Novotna
Summary: The mesomorphic properties of dialkoxy-terminated biphenyl benzoates with lateral substituents were studied, and it was found that lateral substitution causes a decrease in phase transition temperatures and melting points, resulting in mesophases in a wide temperature range.
Article
Biology
M. Macajova, I Cavarga, M. Sykorova, M. Valachovic, V Novotna, B. Bilcik
SAUDI JOURNAL OF BIOLOGICAL SCIENCES
(2020)
Article
Chemistry, Multidisciplinary
Helena Skopalova, Vaclav Kozmik, Michal Smahel, Jiri Svoboda, Oliva Pacherova, Michal Kohout, Vladimira Novotna
Summary: A new series of bent-core liquid crystals with specific structural features were synthesized and studied for their mesomorphic behavior. It was found that the introduction of certain structural features can significantly modify the properties and behavior of the liquid crystals, impacting the polar smectic phases observed.
Article
Crystallography
Helena Skopalova, Petr Spacek, Vaclav Kozmik, Jiri Svoboda, Vladimira Novotna, Damian Pociecha, Michal Kohout
Article
Chemistry, Multidisciplinary
Vladimira Novotna, Sergey Stulov, Vera Hamplova, Martin Cigl, Damian Pociecha
Summary: New lactic acid derivatives were synthesized and compared with similar compounds pursued previously. The materials studied exhibited cholesteric and twist grain boundary phases during cooling. The helical pitch in the cholesteric phase was found to be short, resulting in selective reflection in the visible range during the Ch-TGBA phase transition.
Article
Chemistry, Physical
Natalia Podoliak, Martin Cigl, Vera Hamplova, Damian Pociecha, Vladimira Novotna
Summary: Through studying the new liquid crystalline compounds, we have discovered an antiferroelectric phase with orthoconic properties, promising a wide range of applications with a tilt angle of approximately 45 degrees.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Chemistry, Multidisciplinary
Vladimira Novotna, Sergei Stulov, Damian Pociecha, Vera Hamplova, Ladislav Fekete, Martin Cigl
Summary: The study synthesized and investigated a series of liquid crystal molecules, revealing the importance of the molecular core structure based on two biphenyls connected via ester linkage in the stability and properties of the liquid crystal phase. By comparing with homologues with different lateral substitution positions, the study explained the modified mesomorphic properties and absence of tilted mesophases for the studied series.
Article
Biochemistry & Molecular Biology
Vladimira Novotna, Lubor Lejcek, Vera Hamplova, Jana Vejpravova
Summary: The study focused on the hybrid system of chiral rod-like molecules doped by magnetic nanoparticles in anisotropic fluids, and observed the influence of nanoparticle clusters on defects formation in the smectic phase transition. Attractive elastic forces between nanoparticles were found to be key factors in creating defects in the SmA phase.
Article
Chemistry, Physical
Juraj Malincik, Michal Kohout, Jiri Svoboda, Sergei Stulov, Damian Pociecha, Zuzana Bohmova, Vladimira Novotna
Summary: This study presents a new type of light responsive self-assembling structures based on a spiropyran photoswitchable unit, and its properties were experimentally confirmed. This research is of great significance for understanding the properties and applications of light responsive materials.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Chemistry, Physical
Alevtina Smekhova, Vladimira Novotna, Ladislav Fekete, Radu Abrudan, Mattis Fondell, Vera Hamplova, Boris Ostrovskii
Summary: The study evaluated the spiral ordering characteristics in the cholesteric phase of EZL10/10 LC using resonant soft X-ray scattering at the carbon K edge, revealing a half-pitch of approximately 52 nm. The observed element-specific scattering peaks suggest the presence of coherently scattering finite-size domains formed by cholesteric spirals with lengths of about five pitches, corroborating the periodicity of the surface fingerprint pattern observed by atomic force microscopy.
Article
Crystallography
Diana Jagerova, Michal Smahel, Anna Poryvai, Jan Machacek, Vladimira Novotna, Michal Kohout
Summary: The study presents novel liquid crystals with lateral substitutions and azo groups that enable rapid isomerization upon UV-light and visible light irradiation, with high stability of the formed isomers. UV/Vis and H-1 NMR spectroscopy were used to determine the efficiency of irradiation and composition of photostationary states. The materials easily change their relative configuration not only in solution, but also in the mesophase, leading to fast phase transition from the nematic phase to isotropic liquid.
Article
Crystallography
Vera Hamplova, Sergei Mironov, Martin Cigl, Zuzana Bohmova, Vladimira Novotna, Alexej Bubnov
Summary: Thermotropic liquid crystals are a class of self-organising materials with fluidity and ordering properties, which have broad applications and potential for future advancements. Despite over a hundred years of research, the relationship between molecular structure and mesomorphic properties is still not well-established. Designing and synthesizing new liquid crystalline materials with different molecular structures is a highlighted task for future applications.
LIQUID CRYSTALS AND THEIR APPLICATION
(2021)
Article
Chemistry, Multidisciplinary
Anna Poryvai, Michal Smahel, Marie Svecova, Ahlam Nemati, Sasan Shadpour, Pavel Ulbrich, Timothy Ogolla, Jiao Liu, Vladimira Novotna, Miroslav Veverka, Jana Vejpravova, Torsten Hegmann, Michal Kohout
Summary: Combining cobalt ferrite nanocrystals with organic ligands featuring a robust photosensitive unit and a source of chirality, nanoparticles are developed to serve as a multifunctional and multiaddressable dopant to modify the properties of liquid crystalline matrices. These nanoparticles, when dispersed in achiral liquid crystals, form chiral supramolecular structures that can respond to UV-light illumination and possess strong magnetic response.
Article
Chemistry, Multidisciplinary
Natalia Podoliak, Vladimira Novotna, Vera Hamplova, Damian Pociecha, Martin Cigl
Summary: By optimizing the molecular structure and introducing chemical modifications, we have successfully enhanced the ferroelectric properties of liquid crystalline materials, extending the temperature range of ferroelectric phase and achieving higher spontaneous electric polarization at room temperature.
