Article
Chemistry, Multidisciplinary
Ziqiao Chen, Kenjirou Higashi, Keisuke Ueda, Kunikazu Moribe
Summary: The crystallization mechanisms of organic molecules are still poorly understood, and this study provides direct evidence of mesocrystal formation and oriented attachment in organic pharmaceuticals, which sheds new light on the crystallization of organic molecules and nonclassical crystallization theories.
Article
Materials Science, Ceramics
Yan Xiong, Junwei Li, Fansi Luo
Summary: The abnormal grain growth (AGG) behavior was observed during the solid-state sintering of nano-sized BaTiO3 powder. The results challenged traditional sintering theories and proposed an explanation based on the oriented attachment of smaller grains.
CERAMICS INTERNATIONAL
(2022)
Article
Electrochemistry
Zixue Su, Hui Li
Summary: This work reports an electrochemical synthesis method for (NH4)3TiOF5 mesocrystals consisting of nanocrystalline building units, and reveals the evolution process of mesocrystals with octahedral morphology.
ELECTROCHEMISTRY COMMUNICATIONS
(2022)
Article
Materials Science, Ceramics
Yingzhi Meng, Kang Liu, Xiuyun Zhang, Xiuyun Lei, Jun Chen, Zhao Yang, Biaolin Peng, Changbai Long, Laijun Liu, Chunchun Li
Summary: This study investigated the colossal-permittivity behavior in rare-earth doped BaTiO3 ceramics and identified the coupling of point defects as well as the effects of internal barrier layer capacitance and surface barrier layer capacitor. The study highlights the potential applications of these materials in the miniaturization of electronic components and high-energy storage.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Olga Boytsova, Irina Zhukova, Artem Tatarenko, Tatiana Shatalova, Artemii Beiltiukov, Andrei Eliseev, Alexey Sadovnikov
Summary: The research successfully prepared highly oriented anatase nanoparticles and found that the transition temperature from mesocrystalline anatase to rutile phase is 400 degrees Celsius higher than bulk TiO2. The formation of a small quantity of K-phase nanowhiskers after 800 degrees Celsius in the TiO2-based composite stimulated a fourfold increase in photocatalytic performance.
Article
Nanoscience & Nanotechnology
David Egea-Benavente, Carlos Diaz-Ufano, Alvaro Gallo-Cordova, Francisco Javier Palomares, Jhon Lehman Cuya Huaman, Domingo F. Barber, Maria del Puerto Morales, Jeyadevan Balachandran
Summary: This work analyzes the formation mechanism of cubic magnetic iron oxide mesocrystals by thermal decomposition in organic media, finding a nonclassical pathway via the attachment of crystallographically aligned primary cubic particles and sintering to achieve a sizable single crystal. The solvent 1-octadecene and the surfactant agent biphenyl-4-carboxylic acid are key parameters. The degree of aggregation of the cores forming the final particle strongly affects the magnetic properties and hyperthermia efficiency.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Chenhui Wei, Xinyue Zhao, Ao Zhang, Mengfei Wang, Xinran Zhang, Maoxin Zhang, Jianchuang Wang, Yi Fang, Hao Wu, Chunxiu Zhang
Summary: 2- and 3,6-position bulky group substituted triphenylene discotic carboxylic esters were synthesized and their self-assembly properties were investigated. The results showed that most of them can form long-range ordered columnar superlattices and achieve perfectly aligned monodomains by adjusting the steric hindrance effect of the bulky groups. Moreover, these materials exhibit high charge carrier mobilities, making them promising candidates for organic optoelectronic devices.
NEW JOURNAL OF CHEMISTRY
(2022)
Article
Chemistry, Inorganic & Nuclear
Hamida Gouadria, Mourad Smari, Taoufik Mnasri, Jallouli Necib, Jesus Lopez Sanchez, Pilar Marin, Atul P. Jamale, Rached Ben Younes
Summary: The present study investigates the influence of Fe insertion on the physical properties of Ba0.95Bi0.05Ti1-xFexO3 (x = 0.025, 0.050, and 0.075) synthesized via sol gel method. The resulting samples exhibit tetragonal crystal structure with space group P4mm, and their morphological features suggest variations in microstructure with Fe content. The temperature-dependent dielectric constant shows two transition phases: ferroelectric-paraelectric transition phase (TF-P) and ferroelectric orthorhombic -ferroelectric tetragonal phase (TO-T). Analysis of conductivity curves using Jonscher's augmented equation (for x = 0.025) and Jonscher's power law (for x = 0.075) indicates the Non-Overlapping Small Polaron Tunneling (NSPT) model as the conduction mechanism.
INORGANIC CHEMISTRY COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Marc Montilla, Josep M. Luis, Pedro Salvador
Summary: This study introduces an energy-based method for decomposing static (hyper)polarizabilities, demonstrating origin independence, atomic additivity, and transferability of polarizability tensors. Additionally, the atomic polarizability tensors derived from this method are symmetric by definition.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Materials Science, Ceramics
Fei Shang, Juwen Wei, Yifa Deng, Guixiong Tang, Jiwen Xu, Di Zhou, Huarui Xu, Guohua Chen
Summary: In order to meet the requirements of miniaturization devices in high pulsed power technology, it is crucial to achieve high dielectric breakdown strength (DBS) and large energy storage density in dielectric materials. This study proposes a novel method to precipitate nanocrystals with cubic BaTiO3 phase from glass matrix, which can increase the dielectric constant and maintain high DBS compared to the parent glass. The BaTiO3 glass ceramic demonstrates a high recoverable energy storage density of -3.66 J cm-3 at 1000 kV cm-1 and a high discharge energy density of -3.57 J cm-3, with good thermal stability and an ultra-high peak power density of -910 MW cm-3, making it suitable for high pulsed power technology applications.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2023)
Article
Electrochemistry
Hui Li, Zixue Su
Summary: The 3D ordered superstructures of NH4TiOF3 and (NH4)(2)TiOF4 were synthesized through in-situ evolution from anodic TiO2 nanotube arrays grown on the Ti metal substrate under high current density. These mesocrystals consist of well aligned nanoparticle subunits and can be converted to TiO2 (anatase) mesocrystals with their original exterior shapes retained upon thermal annealing. The formation of NH4TiOF3 and (NH4)(2)TiOF4 mesocrystals involves a nonclassical crystal growth process with fast oriented aggregation of particles assisted by electric field-dipole interaction.
ELECTROCHEMISTRY COMMUNICATIONS
(2021)
Article
Biochemistry & Molecular Biology
J. Ameixa, E. Arthur-Baidoo, J. Pereira-da-Silva, M. Oncak, J. C. Ruivo, M. T. do N. Varella, F. Ferreira da Silva, S. Denifl
Summary: We report electron attachment (EA) measurements and quantum chemical calculations for Coenzyme Q0 (CoQ0), which is a prototype for electron withdrawing CoQn molecules. The mechanisms for the parent anion radical formation in CoQ0 and CoQn (n = 1,2,4) are remarkably distinct. The isoprenoid side chains in CoQn molecules seem to influence the formation of dipole bound states (DBS), while for CoQ0, the parent anion radical is unstable at lower energies due to its short auto-ionization lifetimes.
COMPUTATIONAL AND STRUCTURAL BIOTECHNOLOGY JOURNAL
(2023)
Article
Physics, Applied
Qiang Zhao, HongJing Bi
Summary: This paper investigates the vortex formation in spin-orbit coupled Bose-Einstein condensates with spin-1 and dipolar interactions. By numerically solving the Gross-Pitaevskii equation, the researchers observe that the symmetry of density profiles in vortex lattice formation and the time evolution of angular momentum are broken due to the anisotropy of dipole-dipole interaction. Furthermore, they find that increasing the relative dipole strength decreases the total angular momentum, while increasing the SOC strength improves the rotation efficiency, indicating the dominance of SOC over DDI.
MODERN PHYSICS LETTERS B
(2022)
Article
Chemistry, Multidisciplinary
Nurul Akmal Che Lah, Aqilah Kamaruzaman, Sonia Trigueros
Summary: Understanding the growth mechanism and enhancement preferences of ZnO nanostructures is crucial. The study found that tannic acid plays a role in adjusting the surface state and oriented attachment process of ZnO nanostructures.
Article
Physics, Multidisciplinary
Youssef Khouja, Abderrahim El Allati
Summary: The study focuses on asymmetric and hybrid steering in the Tavis-Cummings model with dipole-dipole interaction (DDI) under intrinsic decoherence, using entropic uncertainty inequalities between two identical atoms for evaluation. The results indicate that phase decoherence stabilizes the direction during time decay. The DDI coupling in the system enhances bi-directionality and stability, while avoiding collapses and violations that affect asymmetric and hybrid steering, respectively. When intrinsic decoherence is introduced, the asymmetric direction remains stationary for weak DDI coupling, while the hybrid direction tends to have the same characteristics for strong DDI coupling.
Article
Chemistry, Multidisciplinary
Kyuichi Yasui, Hiroki Itasaka, Ken-ichi Mimura, Kazumi Kato
Summary: The flexoelectric effect and ferroelectric effect may both influence the dielectric constant at the nanoscale. While the magnitude of the flexoelectric polarization does not change due to strain mismatch at the interface of nanocubes, it does not contribute to the dielectric constant. However, the ferroelectric component parallel to the electric field may have some impact on the dielectric response.
Article
Nanoscience & Nanotechnology
Kyuichi Yasui, Koichi Hamamoto
Summary: Numerical models of solid-state and liquid-phase sintering of CaCO3 at room temperature were developed. It was found that solid-state sintering can still occur under high static pressure, while liquid-phase sintering only occurs under low static pressure.
Article
Physics, Applied
Hiroki Itasaka, Ken-ichi Mimura, Kyuichi Yasui, Koichi Hamamoto, Kazumi Kato
Summary: In this study, the ferroelectric properties of barium titanate nanocube self-assembled monolayers with and without heat treatment were investigated using piezoresponse force microscopy (PFM). The results showed that even without heat treatment, these monolayers were ferroelectric. However, heat treatment changed the ferroelectric polarization distribution in the monolayers, which was attributed to residual stress caused by mechanical interactions.
APPLIED PHYSICS EXPRESS
(2022)
Review
Biochemistry & Molecular Biology
Kyuichi Yasui
Summary: This review focuses on the production of O radicals (oxygen atoms) in acoustic cavitation. Numerical simulations revealed that significant amounts of O radicals are generated inside a heated bubble during the violent collapse through thermal dissociation of water vapor and oxygen molecules. However, the concentration and lifetime of O radicals in the surrounding liquid water are currently unknown. Future studies should investigate the potential role of O radicals in sonochemical reactions in the liquid phase, which are traditionally believed to be dominated by OH radicals and H2O2.
Article
Acoustics
Toru Tuziuti, Kyuichi Yasui
Summary: This paper investigates the role of cavitation bubbles in ultrasonic impregnation by studying the correlation between the intensity of sonoluminescence and the mass increment of the wood material after sonication. It was found that the number density of collapsing ultrasonic cavitation bubbles is related to the degree of ultrasonic impregnation.
ULTRASONICS SONOCHEMISTRY
(2022)
Review
Chemistry, Multidisciplinary
Kyuichi Yasui
Summary: This article reviews the theoretical studies on bulk nanobubbles (UFBs) and discusses their stability, generation, and interaction with solid surfaces. The dynamic equilibrium model is found to be a promising model for UFB stability, and the formation of UFBs is attributed to the production of OH radicals during hydrodynamic or acoustic cavitation. The presence of UFBs accelerates the rupture of liquid film and reduces surface tension. Additionally, the interaction between UFBs and solid surfaces is explored.
Article
Chemistry, Physical
Aissa Dehane, Slimane Merouani, Oualid Hamdaoui, Kyuichi Yasui, Muthupandian Ashokkumar
Summary: In sonochemistry, acoustic bubbles serve as microreactors for producing hydrogen and oxidants. This study developed a novel semi-empirical method using hydrogen sono-production to determine the number density of micro-bubbles during water sonolysis. The results showed that the number density of bubbles ranged from -108 to -1013 L-1 s-1, depending on the experimental conditions, and the calculation method used. The study also found that the number of active bubbles increased with frequency, but decreased when calculated via the total single-bubble yield, especially at higher frequencies and colder liquid temperatures.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2023)
Article
Acoustics
Kyuichi Yasui
Summary: Broad-band noise is used to monitor cavitation activity in various applications, but its origin is still debated. This review discusses two models for the mechanism of broad-band noise: acoustic emissions from chaotically pulsating bubbles and acoustic emissions from bubbles with temporal fluctuation in number. The latter mechanism may be dominant and further studies are needed on bubble cluster dynamics and bubble-bubble interaction in the broad-band noise, especially at low ultrasonic frequencies.
ULTRASONICS SONOCHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Toru Tuziuti, Kyuichi Yasui, Wataru Kanematsu
Summary: The effect of nanobubbles (NBs) on liquid surface tension was studied using three different methods, namely pendant drop (PD), Wilhelmy, and du Nou'y methods, over a wide range of bulk NBs (BNBs) concentrations. In all three methods, the surface tension decreased proportionally with the BNBs concentration, although the proportional constant varied. This behavior was attributed to the surface excess of BNBs at the gas-liquid or solid-liquid interface. The decrease in surface tension was observed to be gradual in the PD method, taking several hundreds of seconds, while it was instant in the Wilhelmy and du Nou'y methods, likely due to electrostatic forces at the solid-liquid interface.
Review
Biochemistry & Molecular Biology
Kyuichi Yasui
Summary: It has been experimentally observed that oxidation and reduction reactions occur in ultrasound-assisted aqueous solutions without any additives. Numerical simulations show that reducing agents produced from air or argon bubbles in water under ultrasound include H, H-2, HO2, NO, HNO2, and sometimes H2O2. These agents can reduce metal ions to form metal nanoparticles in strongly alkaline solutions. Superoxide anion (O-2(-)) and hydrated electrons (e(-)aq) may also play a role in the sonochemical reduction of solutes, especially in strongly alkaline solutions. The influence of ultrasonic frequency on the production of H atoms from cavitation bubbles is also discussed.
Article
Physics, Multidisciplinary
Kyuichi Yasui, Koichi Hamamoto
Summary: Numerical calculations are performed to study the influence of parallel straight dislocations on ionic conductivity and dendrite formation in ceramics. The results show that if the diameter of a dislocation pipe is more than root 2 times larger than the distance between neighboring dislocations, the ionic current density is nearly uniform on the electrode and dendrite formation can be avoided. Moreover, under this condition, the mean ionic conductivity is significantly improved compared to without dislocations.
Review
Chemistry, Physical
Kyuichi Yasui
Summary: In many materials, impurities and imperfections have a significant impact on their physical and chemical properties. This review discusses examples of such materials.
Article
Physics, Condensed Matter
Kyuichi Yasui, Koichi Hamamoto
Summary: The upper limit of dislocation density in slightly-ductile single-crystal ceramics is calculated to improve their properties. The theoretical prediction suggests that introducing appropriate dislocations can significantly increase the ionic conductivity without dendrite formation.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Nanoscience & Nanotechnology
Kyuichi Yasui, Koichi Hamamoto
Summary: The porosity after solid-state sintering is estimated using a simple physical model and empirical formulas based on applied pressure and initial particle size. Comparison with experimental data shows that tight aggregation of CaCO3 nanoparticles significantly increases porosity in solid-state sintering compared to the prediction for isolated nanoparticles.
Review
Biochemistry & Molecular Biology
Kyuichi Yasui
Summary: In comparison with first-principles calculations using partial differential equations, numerical simulations with modeling by ordinary differential equations are more computationally economical and allow for easier tracking of important factors. However, model validation through comparison with experimental or first-principles data is necessary for ODE modeling.
