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arXiv 2025年

作者： Gleeson, J.T. Sprunt, S.N. Jákli, A. Guragain, P. Twieg, R.J. Department of Physics Kent State University KentOH44242 United States Materials Science Graduate Program and Advanced Materials and Liquid Crystal Institute Kent State University KentOH44242 United States Department of Chemistry and Biochemistry Kent State University KentOH44242 United States

The remarkable material DIO presents fascinating behaviors. It has been extensively studied as one of the first materials exhibiting a ferroelectric nematic phase. However, at higher temperatures it exhibits what has been termed the Smectic ZA: identified as an orientationally ordered, antiferroelectric phase with a density modulation in direction perpendicular to the optic axis. At even higher temperatures, this transitions to an apparently normal nematic phase. We have studied the splay-bend Freedericksz transition in the nematic and SmZA phases of the material DIO. Both the magnetic and electric field transitions were utilized. We observed the transitions by measuring effective birefringence and capacitance as well as with polarizing light microscopy. In both the nematic and the SmZA states the field induced transitions resemble (in numerous aspects) the classical Freedericksz transition. These enable determinations of several fundamental material parameters and also reveal intriguing aspects of the SmZA phase, including the surprising behavior of the elastic constants and the dielectric anisotropy. Detailed comparison with Frank elastic theory of the Freedericksz transition [1] shows that the N phase behaves largely as expected, but the transition in the SmZA phase differs significantly. Two specific examples of this are the onset of striations in the Freedericksz distorted state, and the presence of optical biaxiality. The former may be related to the periodic Freedericksz transition [2] as it coincides with a large increase in the splay elastic constant. The latter has been predicted for the SmZA phase, but not previously observed. [3] © 2025, CC BY.

关键词： Antiferroelectricity

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Twist, splay, and uniform domains in ferroelectric nematic liquid crystals

arXiv

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arXiv 2025年

作者： Lavrentovich, Maxim O. Kumari, Priyanka Lavrentovich, Oleg D. Department of Earth Environment and Physics Worcester State University WorcesterMA01602 United States Department of Physics & Astronomy University of Tennessee KnoxvilleTN37996 United States Advanced Materials and Liquid Crystal Institute Kent State University KentOH44240 United States Materials Science Graduate Program Kent State University KentOH44240 United States Department of Physics Kent State University KentOH44240 United States

The recently-discovered ferroelectric nematic (NF) liquid crystal presents a host of defect phenomena due to its unique polar nature and long-ranged electrostatic interactions. Like the solid state ferroelectrics, the depolarization field in the material favors a spontaneous spatial variation of the polarization P, manifesting in myriad ways including a twist in the bulk and different arrangements of alternating polarization domains. Unlike the solid-state ferroelectrics with a bulk crystalline structure, the configuration of the NF fluids is determined not only by the reduction of depolarization fields but also by the alignment of molecules at interfaces. In this work, we consider an NF confined to a thin cell, pre-patterned with various types of apolar surface anchoring produced by photoalignment. For uniform planar alignment, we find that the sample forms a series of striped domains. For a cell pre-patterned with a radial +1 defect pattern, the NF breaks up into "pie-slice" polarization domains. We calculate the elastic and electrostatic energy balance which determines the observed configurations and demonstrate that the electrostatic interactions tend to decrease the characteristic domain size λ while the elastic and surface anchoring interactions facilitate a larger λ. We also demonstrate that ionic screening mitigates electrostatic interactions, increasing λ and, above some critical concentration, eliminating the domains altogether. Copyright © 2025, The Authors. All rights reserved.

关键词： Depolarization

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Giant Electro-Viscous Effects in Polar Fluids with Paraelectric–Modulated Antiferroelectric–Ferroelectric Phase Sequence

arXiv

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arXiv 2025年

作者： Nishikawa, Hiroya Salamon, Péter Máthé, Marcell Tibor Jákli, Antal Araoka, Fumito 2-1 Hirosawa Saitama Wako351-0198 Japan HUN-REN Wigner Research Centre for Physics P.O. Box 49 BudapestH-1525 Hungary Material Science Graduate Program and Advanced Materials and Liquid Crystal Institute Kent State University KentOH44242 United States Department of Physics Kent State University KentOH44242 United States

The recently discovered ferroelectric nematic liquid-crystal material DIO exhibits an antiferroelectric (AF) phase, characterized by a sinusoidally modulated structure between the paraelectric (P) and ferroelectric (F) nematic phases. Although these sinusoidal modulated structures associated with the P–AF–F phase sequence is commonly observed in solid ferroelectrics, their presence in soft matter systems is scarce. This study is aimed at examining the macroscopic properties of DIO, identifying unique rheological properties, such as switching between shear thinning and shear thickening behaviors at certain shear rate in the ferroelectric nematic phase. Additionally, a significant electroviscous effect is observed, with the viscosity increasing by 70 times under an ultra-low electric field of 0.15 V µm−1 at the AF–F transition. Copyright © 2025, The Authors. All rights reserved.

关键词： Shear thinning

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Early and advanced crystallization stages in lithia-alumina-silica glasses nucleated by ZrO2

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Ceramics International 2025年

作者： Revelo, Raúl Julián Souza, Mauricio Lima Pena, Rafaella Bartz Yoshida, Satoshi Zanotto, Edgar Dutra Federal University of São Carlos Graduate Program in Materials Science and Engineering SP São Carlos13565-905 Brazil São Carlos Institute of Physics University of São Paulo SP São Carlos13566-590 Brazil Materials Integration Laboratories AGC Inc 1-1 Suehiro-Cho Tsurumi-Ku Kanagawa Yokohama230-0045 Japan

ZrO2 is one of the most effective and widely used nucleating agents in various families of glass-ceramics;however, its detailed mechanism remains a subject of debate. Understanding its nucleation mechanism requires a thorough analysis of microstructural evolution and the identification of factors influencing this process. This study investigates the effects of ZrO2 incorporation on the internal nucleation and microstructural evolution in stoichiometric LAS (Li2O·Al2O3·nSiO2) glass-ceramics of varying composition. Glasses with different SiO2 molar ratios (n = 2, 4, 5, and 6) were prepared with ZrO2 additions of 3.0 and 3.5 mol%. Several thermal treatments were employed, followed by characterization using XRD, SEM, STEM, and Raman spectroscopy. The results indicate that a minimum of 3.5 mol% ZrO2 is required to induce internal nucleation in LAS glasses with n = 4, 5, and 6. In these compositions, Zr-enriched regions formed through liquid-liquid phase separation serve as preferential sites for ZrO2 crystal precipitation, which subsequently induces the nucleation of β-quartz solid solution. Upon further treatment at higher temperatures, this metastable phase transforms into β-spodumene or its solid solution. As expected, increasing SiO2 content enhances glass network polymerization, as evidenced by the increased presence of Q3 species in Raman spectroscopy, leading to higher characteristic temperatures of glass transition and peak crystallization in DSC analyses. A higher SiO2 content results in fewer but larger crystals, whereas a lower SiO2 content promotes a higher number density of crystals within the glass matrix. © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Glass ceramics

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Polarimetric Study of GRS 1915+105: Estimation of Interstellar Polarization Component

arXiv

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arXiv 2025年

作者： Inokuchi, Jin Kawabata, Koji S. Uemura, Makoto Hiraga, Hiroyuki Hiroshima University High School Fukuyama 5-14-1 Kasuga-cho Fukuyama Hiroshima721-8551 Japan Hiroshima Astrophysical Science Center Hiroshima University 1-3-1 Kagamiyama Hiroshima Higashi-Hiroshima739-8526 Japan Physics Program Graduate School of Advanced Science and Engineering Hiroshima University 1-3-1 Kagamiyama Hiroshima Higashi-Hiroshima739-8526 Japan

GRS 1915+105 is a well-known X-ray binary system composed of a black hole with a low-mass companion star and is recognized for emitting relativistic jets. Imazato et al. (2021) performed extensive polarimetry in a near-infrared (NIR) Ks band from 2019 April through December when GRS 1915+105 experienced an X-ray low luminous state and found almost stable polarization of PP = 2.42% ± 0.08%. We performed NIR polarimetry of the field stars around GRS 1915+105 in 2023 April and October, and found that the field stars that are not listed in Gaia DR3 and StarHorse2 catalogues show well aligned polarization that is consistent with GRS 1915+105's polarization. Those suggest that the interstellar clouds existing beyond 4 kpc causes the large interstellar extinction and that the polarization the GRS 1915+105 is mostly originated from the magnetically aligned dust grains within the clouds. Therefore, the jet-origin synchrotron radiation polarization would have given only minor contribution in the NIR band in 2019 Apr-Dec. © 2025, CC BY.

关键词： Infrared devices

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Launching a Women-Focused Faculty and Trainee Development program

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Academic Radiology 2025年

作者： Brixey, Anupama G. Spalluto, Lucy B. DeWeese, Lindsay Chief of Cardiac Imaging and Ultrasound Portland VA Health Care System VA Site Director of the OHSU Radiology Residency Founder and Past Chair OHSU Women in Radiology Group Joint Appointment Pulmonary & Critical Care Oregon Health & Science University (OHSU) 3181 SW Sam Jackson Park Road Portland 97239 OR Vanderbilt university Medical Center Department of Radiology and Radiological Sciences Nashville TN United States Vanderbilt Ingram Cancer Center Nashville TN United States Section Chief Imaging Physics Program Director Diagnostic Imaging Physics Residency Assistant Program Director Medical Physics Graduate Program Department of Diagnostic Radiology Oregon Health & Science University Portland OR United States

Rationale and Objectives: Women in the fields of radiology and medical physics lack advancement opportunities and are under-represented in leadership positions. There is a paucity of research on specific interventions to address this problem. Materials and Methods: We developed and launched the “Women-Focused Faculty and Trainee Development program” at an academic university to improve gender-based knowledge gaps contributing to lack of promotional advancement and leadership opportunities. An eight-event curriculum was developed based on educational gaps identified on pre-intervention surveys;assessment of goal fulfillment was determined by post-intervention surveys. Results: Pre-intervention, 62% of women faculty were satisfied with their pace of professional advancement and 69% believed they would be promoted at an appropriate time compared to 100% post-intervention (p-value 0.008 and 0.02, respectively). The pre-intervention survey demonstrated that the top three obstacles to professional development were lack of adequate mentorship, inadequate resources for research, and limited understanding of promotion and tenure. Post-intervention data demonstrated that 88% of women faculty and trainees believed the program helped them achieve their goals. The majority of all program participants (both men and women) agreed their knowledge had increased on all curriculum topics. There were differences in perceptions of gender inequities between men and women on several topics including whether fewer women pursue academic promotion, whether fewer women do not pursue promotion due to lack of institutional/departmental support, and whether there are departmental discrepancies in salary, all statistically significant. Conclusion: With implementation of a formal development program, significant positive impacts on women's ability to achieve professional goals, gain mentorship opportunities, and improve satisfaction with their pace of professional advancement can be achieved. © 20

关键词： Curriculum Educational development program Gender inequities Gender perceptions Women in radiology

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Investigating the effects of QCD matter’s electrical conductivity on charge dependent directed flow

arXiv

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arXiv 2025年

作者： Benoit, Nicholas J. Miyoshi, Takahiro Nonaka, Chiho Takahashi, Hiroyuki R. Physics Program Graduate School of Advanced Science and Engineering Hiroshima University Higashi-Hiroshima739-8511 Japan Department of Physics Nagoya University Nagoya464-8602 Japan Kobayashi Maskawa Institute Nagoya University Nagoya464-8602 Japan International Institute for Sustainability with Knotted Chiral Meta Matter Hiroshima University Higashi-Hiroshima739-8511 Japan Department of Natural Sciences Faculty of Arts and Sciences Komazawa University Tokyo154-8525 Japan

Charge dependent directed flow is an important observable of electromagnetic fields in relativistic heavy-ion collisions. We demonstrate how the difference in charge dependent directed flows between protons and antiprotons is sensitive to the resistivity, inverse of quark-gluon plasma’s electric conductivity, over different collision centralities. Our model numerically solves the 3+1D relativistic resistive magneto-hydrodynamic (RRMHD) equations, assuming the electric conductivity to be a scalar. For this work, we focus on symmetric Au + Au collisions at the top RHIC energy of √s = 200 GeV. We illustrate the time evolution of the electromagnetic fields in our model and connect that to the charge dependent directed flow results. Our results highlight the importance of modeling quark-gluon plasma’s electric conductivity for charge dependent observables in relativistic heavy-ion collisions. Copyright © 2025, The Authors. All rights reserved.

关键词： Heavy ions

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Improving the sensitivity of fiber-optic SPR sensor via radially polarized beam excitation

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Chinese Optics Letters 2009年第10期7卷 909-911页

作者：阎杰鲁拥华王沛顾春郑荣升陈勇明海詹其文 Department of Physics University of Science and Technology of ChinaAnhui Key Laboratory of Optoelectronic Science and Technology Electro-Optics Graduate Program University of Dayton

We study the sensing properties of an intensity-modulated fiber-optic surface plasmon resonance （SPR） sensor using radially polarized beam （RPB）. Because of the rotational symmetry of fiber and RPB, surface plasmon can be excited more efficiently at the sensor surface, which results in an obvious improvement of the sensitivity. Our experiments demonstrate that the sensitivity in the case of RPB illumination is three times higher than that of linearlv polarized beam illumination.

关键词： Fiber optics Plasmons Sensors

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Nonsaturated large magnetoresistance and transport dynamics in a n-doped cryogenic WSe2 field-effect device

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Physical Review B 2025年第12期111卷 125307-125307页

作者： Wei-Chen Lin Ching-Chen Yeh Jia-Zhu Zou Nhat Anh Nguyen Phan Inayat Uddin Hai Yen Le Thi Kenji Watanabe Takashi Taniguchi Gil-Ho Kim Department of Engineering and System Science National Tsing Hua University Hsinchu 300 Taiwan Taiwan International Graduate Program Academia Sinica Taipei 115 Taiwan Department of Physics National Taiwan University Taipei 106 Taiwan Department of Electrical and Computer Engineering Sungkyunkwan University (SKKU) Suwon 164 Republic of Korea Sungkyunkwan Advanced Institute of Nano Technology (SAINT) Sungkyunkwan University (SKKU) Suwon 16419 Republic of Korea Research Center for Electronic and Optical Materials National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan Research Center for Materials Nanoarchitectonics National Institute for Materials Science 1-1 Namiki Tsukuba 305-0044 Japan

Interest in the two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) continues to intensify, driven by their suitable band gaps to supplant silicon as next-generation semiconductor materials. Among various TMDs, tungsten diselenide (WSe2) is renowned for its superior electrical properties in carrier density and mobility under ambient conditions. Despite its notable attributes, the behavior of monolayer WSe2 in the electron-doped regime under cryogenic conditions remains largely uncharted, particularly concerning its magnetotransport properties. In this study, we reveal the transport mechanisms of monolayer WSe2 from high temperatures down to the cryogenic regime. As evident by Efros–Shklovskii variable-range hopping (E-S VRH) in the cryogenic regime, strong Coulomb interactions arise between electrons. Above 8 K, an uncommon nonsaturated quadratic large magnetoresistance (MR) can be explained by the wave-function shrinkage model, which is consistent with the E-S VRH transport mechanism. Notably, the nonsaturated quadratic large MR shows a magnitude up to 1740% at 13 T. These findings underscore the potential applications for monolayer WSe2 in cryogenic field-effect devices, magnetic sensors, and memory devices and mark a significant advance in magnetotransport research.

关键词： Monolayers

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A novel liquid-phase plasma discharge process for single-step emulsification and continuous biodiesel production

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Fuel 2025年 400卷

作者： Palm, Maíra O. Pavani, Lucas Y. Senff, Luciano Duarte, Diego A. Catapan, Rafael C. Graduate Program in Mechanical Science and Engineering (PPGECM) Federal University of Santa Catarina SC Joinville 89219-600 Brazil Graduate Program in Material Science and Engineering (PGMAT) Federal University of Santa Catarina SC Florianópolis 88040-900 Brazil Physics Graduate Program (PPGF) Santa Catarina State University SC Joinville 89219-710 Brazil Graduate Program in Mechanical Engineering (POSMEC) Federal University of Santa Catarina SC Florianópolis 88040-900 Brazil

Plasma-assisted transesterification has emerged as a promising advanced method for biodiesel production, offering reduced reaction times and enhanced ester yields. Unlike conventional thermal processes, plasma technology operates at room temperature, supplying required energy through electrical discharge. However, in the absence of thermal energy, mass transfer limitations often necessitate a preliminary mixing step. This study introduces a novel liquid-phase plasma discharge process that simultaneously emulsifies reactants and enables continuous biodiesel production in a single step, eliminating the need for prior mixing. Optical microscopy and spectrophotometry techniques confirmed the formation of a stable, monodisperse emulsion of oil and methanol. Key factors influencing biodiesel synthesis included catalyst concentration, discharge voltage, and their interactions with reaction time. The optimized conditions of 15 min of reaction, 7.8 kV discharge voltage, and 1 % sodium methoxide resulted in a biodiesel with 97.9 % methyl ester content. This approach demonstrates the potential of plasma technology for efficient and sustainable biodiesel production. © 2025 Elsevier Ltd

关键词： Biodiesel Emulsification Liquid-phase plasma discharge Transesterification

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