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Non-Kramers doublet ground state in a quaternary cubic compound PrRu_(2)In_(2)Zn_(18) investigated by ultrasonic measurements

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Chinese Physics B 2024年第6期33卷 405-411页

作者：张化远 Kazuhei Wakiya Mitsuteru Nakamura Masahito Yoshizawa Yoshiki Nakanish Graduate School of Science and Engineering Iwate UniversityMorioka 020-8551Japan

We performed ultrasonic measurements on a quaternary cubic compound PrRu_(2)In_(2)Zn_(18) to explore the ground state properties derived from non-Kramers Γ_(3) doublet of Pr^(3+).PrRu_(2)In_(2)Zn_(18) is a quaternary derivative of the ternary compound PrRu_(2)Zn_(20) that exhibits a structural phase transition at T_S=138 *** PrRu_(2)In_(2)Zn_(18),the Zn atoms at the 16c site in PrRu_(2)Zn_(20) are selectively replaced by In atoms.A monotonic increase was observed in the temperature dependence of elastic constants C_L=(C_(11)+2C_(12)+4C_(44))/3 and C_(T)=(C_(11)-C_(12)+C_(44))/3 in the temperature range around T_(S) to which an elastic softening was observed in(C_(11)-C_(12))/2 for PrRu_(2)Zn_(20).The disappearance of the softening indicates that the structural transition in PrRu_(2)Zn_(20) is suppressed by the substitution of Zn ions by In ones with a larger ionic ***,the C_(T) of PrRu_(2)In_(2)Zn_(18) exhibits a precursor Curie-type elastic softening toward low temperatures being responsible for the non-Kramers Γ_(3) ground *** discuss the ground state and the evolution of the elastic properties of the different single-crystal samples of PrRu_(2)In_(2)Zn_(18) grown under different conditions.

关键词： ultrasonic measurements non-Kramers doublet structural phase transition crystalline electric field effect

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Application of ultrasonic measurements for Determination of Setting and Hardening in Cement Paste

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Journal of Civil Engineering and Architecture 2011年第3期5卷 278-283页

作者： Ivan Gabrijel Dunja Mikulic Bojan Milovanovic Faculty of Civil Engineering University of Zagreb Zagreb Croatia

Concrete setting and hardening processes are the most critical phases during construction works, influencing properties of a concrete structure. The initial set is important as it provides an estimate when concrete has reached a point that it can no longer he vibrated without damaging concrete. The point at which final set occurs is important since it provides an estimate when the development of concrete strength and stiffness starts. In this study, experimental work is performed under laboratory conditions to indentify the setting time of cement paste using ultrasonic waves. Correlation between the ultrasonic wave parameters （speed, amplitude and energy） passing through the fresh cement paste and setting time determined using the Vicat test method is analyzed. A method of acoustic emission is also used and acoustic signals recorded in cement paste during hydration are presented.

关键词： Cement hydration setting time ultrasonic measurements acoustic emission

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Ferromagnetic–paramagnetic transition temperature in bulk and nanostructured La_(0.7)Sr_xCa_(0.3-x)MnO_3(x=0.10, 0.15, and 0.20) manganite materials

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Rare Metals 2017年第6期36卷 501-511页

作者： Somasundaram Praveen Kumar Kathiresan Sakthipandi Ramamurthy Gayathiri Mathu Sridhar Panday Arumugam Karthik Venkatachalam Rajendran Centre for Nano Science and Technology K.S. Rangasamy College of Technology Anna University Research and Development Centre Bharathiar University

Series of bulk and nanostructured La0.7SrxCa0.3-xMnO3（x = 0.10, 0.15, and 0.20） manganites were synthesized and characterized using different techniques. In the series, both the bulk and nanostructured La0.7Sr0.10Ca0.20MnO3 and La0.7Sr0.20Ca0.10MnO3 manganites have orthorhombic and rhombohedral structures, whereas La0.7Sr0.15Ca0.15MnO3 manganite has rhombohedral and orthorhombic structures, respectively. Online ultrasonic velocity and attenuation measurements were taken through an indigenously designed ultrasonic setup, and the analysis was done from 300 to 400 K during the aging of the samples to explore the structural/phase transitions. The bulk and nanocrystalline La0.7SrxCa0.3-xMnO3 perovskite samples show the particle size distribution in the range of 197-943 and 24-93 nm, respectively. The addition of Sr^2＋ alters the size of particles, which decrease in size. The observed anomaly in ultrasonic velocities, attenuations, and elastic moduli is correlated with the ferromagnetic-paramagnetic（FM-PM） transition temperature（TC） in both bulk and nanocrystalline perovskites. In addition, the shift in TC and the magnitude and width of observed anomaly are correlated with the value of x to study the behavior of TC.

关键词： Magnetic material ultrasonic measurements Elastic properties Phase transition

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measurements of elastic properties and their dependencies within a damage mechanics workflow

Rock Mechanics Bulletin

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Rock Mechanics Bulletin 2023年第4期2卷 84-94页

作者： Erik PKnippel Qiquan Xiong Ana Paula Villaquiran Vargas Jesse C.Hampton Geomechanics and Damage Group(GeoD) Department of Civil and Environmental EngineeringUniversity of Wisconsin-MadisonUSA

Experimental rock mechanics testing provides a controlled and effective method for measuring physical properties,their dependencies,and their evolution due to the addition of localized *** understand the contributions of microcracks to first order changes in compliance,the behavior of initial undamaged properties of a material should be comprehensively investigated as a function of stress,load path,and load *** perform a comprehensive study of elastic properties and their dependence on a variety of materials exhibiting nonlinearity,and varying levels of anisotropy in elastic *** programmatically perturb the testing environment of the specimens under triaxial *** moduli are measured within each test,and along multiple discrete loading paths for multistage tests as a function of stress,focusing on a set launch *** single stage triaxial tests per rock type are performed to calculate Mohr-Coulomb failure criteria,and ultrasonic velocities are captured during compression for establishing the upper bound of elastic *** wave velocity for granite experiences a maximum value at a lower differential stress than maximum volumetric *** displays a similar trend at the highest confining pressure,while these two maxima converge under the lowest confining pressure.

关键词： Triaxial test Elastic moduli ultrasonic measurements Damage mechanics Rock nonlinear behavior

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ultrasonic Resonator Techniques for Broad-band Spectroscopy and for High-resolution Sound Velocity Measurement of Liquids

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Journal of Measurement Science and Instrumentation 2010年第1期1卷 1-9页

作者： Udo Kaatze Frieder Eggers Drittes Physikalisches lnstitut Georg-August-Universitgit GOttingen Cottingen 37077 Germany Max-Planck-lnstitut fuer Biophysikalische Chemie Gottingen 37077 Germany

This review gives a short introduction into the principles of ultrasonic measurement techniques for liquids, using cavity resonators. Guidelines for the resonator design in broad-band ultrasonic stxctroscopy as well as in high-resolution single-frequncy or narrowband applications are presented. Deviations of the field configuration in real cells frtxn that in an ideal resonator are discussed and relations for the mode spectrum of cavity fields are given. Recent resonator measurement procedures and methods of data evaluation are mentioned briefly. Some examples of measurements show the extended usability of ultrasonic resonator techniques in basic science and in a wide range of applications for rrkaterials characterization, in manufacturing processes, as well as in control routines.

关键词： ultrasonic measurements liquids sound velocity attenuation coefficient resonator techniques ultrasonic spectrometry

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