Articles de revues : « Supercooled water, density, metastability »

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Soper, A. K. « Density minimum in supercooled confined water ». Proceedings of the National Academy of Sciences 108, n^o 47 (11 novembre 2011) : E1192. http://dx.doi.org/10.1073/pnas.1112629108.

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English, Niall J., Peter G. Kusalik et John S. Tse. « Density equalisation in supercooled high- and low-density water mixtures ». Journal of Chemical Physics 139, n^o 8 (28 août 2013) : 084508. http://dx.doi.org/10.1063/1.4818876.

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Lin, Chuanlong, Jesse S. Smith, Stanislav V. Sinogeikin et Guoyin Shen. « Experimental evidence of low-density liquid water upon rapid decompression ». Proceedings of the National Academy of Sciences 115, n^o 9 (12 février 2018) : 2010–15. http://dx.doi.org/10.1073/pnas.1716310115.

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Water is an extraordinary liquid, having a number of anomalous properties which become strongly enhanced in the supercooled region. Due to rapid crystallization of supercooled water, there exists a region that has been experimentally inaccessible for studying deeply supercooled bulk water. Using a rapid decompression technique integrated with in situ X-ray diffraction, we show that a high-pressure ice phase transforms to a low-density noncrystalline (LDN) form upon rapid release of pressure at temperatures of 140–165 K. The LDN subsequently crystallizes into ice-Ic through a diffusion-controlled process. Together with the change in crystallization rate with temperature, the experimental evidence indicates that the LDN is a low-density liquid (LDL). The measured X-ray diffraction data show that the LDL is tetrahedrally coordinated with the tetrahedral network fully developed and clearly linked to low-density amorphous ices. On the other hand, there is a distinct difference in structure between the LDL and supercooled water or liquid water in terms of the tetrahedral order parameter.

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Xie, Yonglin, Karl F. Ludwig, Guarionex Morales, David E. Hare et Christopher M. Sorensen. « Noncritical behavior of density fluctuations in supercooled water ». Physical Review Letters 71, n^o 13 (27 septembre 1993) : 2050–53. http://dx.doi.org/10.1103/physrevlett.71.2050.

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Palmer, Jeremy C., Rakesh S. Singh, Renjie Chen, Fausto Martelli et Pablo G. Debenedetti. « Density and bond-orientational relaxations in supercooled water ». Molecular Physics 114, n^o 18 (13 mai 2016) : 2580–85. http://dx.doi.org/10.1080/00268976.2016.1179351.

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Li, Peizhao, Haibao Lu et Yong-Qing Fu. « Phase transition of supercooled water confined in cooperative two-state domain ». Journal of Physics : Condensed Matter 34, n^o 16 (23 février 2022) : 165403. http://dx.doi.org/10.1088/1361-648x/ac519b.

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Abstract The question of ‘what is the structure of water?’ has been regarded as one of the major scientific conundrums in condensed-matter physics due to the complex phase behavior and condensed structure of supercooled water. Great effort has been made so far using both theoretical analysis based on various mathematical models and computer simulations such as molecular dynamics and first-principle. However, these theoretical and simulation studies often do not have strong evidences of condensed-matter physics to support. In this study, a cooperative domain model is formulated to describe the dynamic phase transition of supercooled water between supercooled water and amorphous ice, both of which are composed of low- and high-density liquid water. Free volume theory is initially employed to identify the working principle of dynamic phase transition and its connection to glass transition in the supercooled water. Then a cooperative two-state model is developed to characterize the dynamic anomalies of supercooled water, including density, viscosity and self-diffusion coefficient. Finally, the proposed model is verified using the experimental results reported in literature.

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Blahut, Aleš, Jiří Hykl, Pavel Peukert et Jan Hrubý. « Dual-capillary dilatometer for density measurements of supercooled water ». EPJ Web of Conferences 264 (2022) : 01004. http://dx.doi.org/10.1051/epjconf/202226401004.

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An apparatus tailored to accurate density measurements of supercooled water, i.e. liquid water in a metastable state below the freezing point temperature, was recently developed at the Institute of Thermomechanics of the Czech Academy of Sciences. The apparatus, dual-capillary dilatometer, is described, together with the measurement procedure and the evaluation methodology. The primary result of the dual-capillary method are relative densities with respect to the density at a reference temperature and given pressure. In order to calculate absolute densities, densities at the reference temperature as a function of pressure are needed. For calculation of such pressure dependence of density, so called thermodynamic integration involving literature thermodynamic data and our experimental results is used. The dual-capillary dilatometer was successfully employed in density measurements of ordinary water, heavy water and seawater. The data in the temperature range from 238.15 to 303.15 K at pressures from atmospheric up to 200 MPa are presented and compared with respective IAPWS formulations of thermodynamic properties. The data for ordinary water are also compared with an accurate equation of state for supercooled water of Holten et al. (2014) revealing good mutual agreement. The expanded uncertainty of relative densities acquired by means of the dual-capillary method is estimated to be lower than 50 ppm.

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Peukert, Pavel, Michal Duška, Jiří Hykl, Petr Sladký, Zbyněk Nikl et Jan Hrubý. « Callibration of capillaries for density measurement of supercooled water ». EPJ Web of Conferences 92 (2015) : 02067. http://dx.doi.org/10.1051/epjconf/20159202067.

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Kaneko, Toshihiro, Jaeil Bai, Takuma Akimoto, Joseph S. Francisco, Kenji Yasuoka et Xiao Cheng Zeng. « Phase behaviors of deeply supercooled bilayer water unseen in bulk water ». Proceedings of the National Academy of Sciences 115, n^o 19 (24 avril 2018) : 4839–44. http://dx.doi.org/10.1073/pnas.1802342115.

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Akin to bulk water, water confined to an isolated nanoslit can show a wealth of new 2D phases of ice and amorphous ice, as well as unusual phase behavior. Indeed, 2D water phases, such as bilayer hexagonal ice and monolayer square ice, have been detected in the laboratory, confirming earlier computational predictions. Herein, we report theoretical evidence of a hitherto unreported state, namely, bilayer very low density amorphous ice (BL-VLDA), as well as evidence of a strong first-order transition between BL-VLDA and the BL amorphous ice (BL-A), and a weak first-order transition between BL-VLDA and the BL very low density liquid (BL-VLDL) water. The diffusivity of BL-VLDA is typically in the range of 10−9 cm2/s to 10−10 cm2/s. Similar to bulk (3D) water, 2D water can exhibit two forms of liquid in the deeply supercooled state. However, unlike supercooled bulk water, for which the two forms of liquid can coexist and merge into one at a critical point, the 2D BL-VLDL and BL high-density liquid (BL-HDL) phases are separated by the highly stable solid phase of BL-A whose melting line exhibits the isochore end point (IEP) near 220 K in the temperature−pressure diagram. Above the IEP temperature, BL-VLDL and BL-HDL are indistinguishable. At negative pressures, the metastable BL-VLDL exhibits a spatially and temporally heterogeneous structure induced by dynamic changes in the nanodomains, a feature much less pronounced in the BL-HDL.

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Liu, D., Y. Zhang, C. C. Chen, C. Y. Mou, P. H. Poole et S. H. Chen. « Observation of the density minimum in deeply supercooled confined water ». Proceedings of the National Academy of Sciences 104, n^o 23 (25 mai 2007) : 9570–74. http://dx.doi.org/10.1073/pnas.0701352104.

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Kim, Kyung Hwan, Katrin Amann-Winkel, Nicolas Giovambattista, Alexander Späh, Fivos Perakis, Harshad Pathak, Marjorie Ladd Parada et al. « Experimental observation of the liquid-liquid transition in bulk supercooled water under pressure ». Science 370, n^o 6519 (19 novembre 2020) : 978–82. http://dx.doi.org/10.1126/science.abb9385.

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We prepared bulk samples of supercooled liquid water under pressure by isochoric heating of high-density amorphous ice to temperatures of 205 ± 10 kelvin, using an infrared femtosecond laser. Because the sample density is preserved during the ultrafast heating, we could estimate an initial internal pressure of 2.5 to 3.5 kilobar in the high-density liquid phase. After heating, the sample expanded rapidly, and we captured the resulting decompression process with femtosecond x-ray laser pulses at different pump-probe delay times. A discontinuous structural change occurred in which low-density liquid domains appeared and grew on time scales between 20 nanoseconds to 3 microseconds, whereas crystallization occurs on time scales of 3 to 50 microseconds. The dynamics of the two processes being separated by more than one order of magnitude provides support for a liquid-liquid transition in bulk supercooled water.

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Nomura, Kentaro, Toshihiro Kaneko, Jaeil Bai, Joseph S. Francisco, Kenji Yasuoka et Xiao Cheng Zeng. « Evidence of low-density and high-density liquid phases and isochore end point for water confined to carbon nanotube ». Proceedings of the National Academy of Sciences 114, n^o 16 (3 avril 2017) : 4066–71. http://dx.doi.org/10.1073/pnas.1701609114.

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Possible transition between two phases of supercooled liquid water, namely the low- and high-density liquid water, has been only predicted to occur below 230 K from molecular dynamics (MD) simulation. However, such a phase transition cannot be detected in the laboratory because of the so-called “no-man’s land” under deeply supercooled condition, where only crystalline ices have been observed. Here, we show MD simulation evidence that, inside an isolated carbon nanotube (CNT) with a diameter of 1.25 nm, both low- and high-density liquid water states can be detected near ambient temperature and above ambient pressure. In the temperature–pressure phase diagram, the low- and high-density liquid water phases are separated by the hexagonal ice nanotube (hINT) phase, and the melting line terminates at the isochore end point near 292 K because of the retracting melting line from 292 to 278 K. Beyond the isochore end point (292 K), low- and high-density liquid becomes indistinguishable. When the pressure is increased from 10 to 600 MPa along the 280-K isotherm, we observe that water inside the 1.25-nm-diameter CNT can undergo low-density liquid to hINT to high-density liquid reentrant first-order transitions.

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Urquidi *, J., C. J. Benmore, P. A. Egelstaff, M. Guthrie, S. E. Mclain, C. A. Tulk, D. D. Klug et J. F. C. Turner. « A structural comparison of supercooled water and intermediate density amorphous ices ». Molecular Physics 102, n^o 19-20 (10 octobre 2004) : 2007–14. http://dx.doi.org/10.1080/00268970412331292650.

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Zhang, Yang, Kao-Hsiang Liu, Marco Lagi, Dazhi Liu, Kenneth C. Littrell, Chung-Yuan Mou et Sow-Hsin Chen. « Absence of the Density Minimum of Supercooled Water in Hydrophobic Confinement ». Journal of Physical Chemistry B 113, n^o 15 (16 avril 2009) : 5007–10. http://dx.doi.org/10.1021/jp900641y.

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Mallamace, Francesco, Giuseppe Mensitieri, Domenico Mallamace, Martina Salzano de Luna et Sow-Hsin Chen. « Some Aspects of the Liquid Water Thermodynamic Behavior : From The Stable to the Deep Supercooled Regime ». International Journal of Molecular Sciences 21, n^o 19 (1 octobre 2020) : 7269. http://dx.doi.org/10.3390/ijms21197269.

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Liquid water is considered to be a peculiar example of glass forming materials because of the possibility of giving rise to amorphous phases with different densities and of the thermodynamic anomalies that characterize its supercooled liquid phase. In the present work, literature data on the density of bulk liquid water are analyzed in a wide temperature-pressure range, also including the glass phases. A careful data analysis, which was performed on different density isobars, made in terms of thermodynamic response functions, like the thermal expansion αP and the specific heat differences CP−CV, proves, exclusively from the experimental data, the thermodynamic consistence of the liquid-liquid transition hypothesis. The study confirms that supercooled bulk water is a mixture of two liquid “phases”, namely the high density (HDL) and the low density (LDL) liquids that characterize different regions of the water phase diagram. Furthermore, the CP−CV isobars behaviors clearly support the existence of both a liquid–liquid transition and of a liquid–liquid critical point.

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Godizov, A. G., et A. A. Godizov. « On the objective origin of the phase transitions and metastability in many-particle systems ». International Journal of Modern Physics B 28, n^o 24 (5 août 2014) : 1450163. http://dx.doi.org/10.1142/s021797921450163x.

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The modern equilibrium statistical mechanics, intended to link microscopic dynamics to thermodynamic laws for macroscopic quantities, is faced with significant difficulties, as applied to the description of the macroscopic properties of real condensed media within wide thermodynamic ranges, including the vicinities of the phase transition points. A particular problem is the absence of metastable states in the Gibbs statistical mechanics of the systems composed of finite number of particles. Nevertheless, accordance between equilibrium statistical mechanics and thermodynamics of condensed media is achievable if we take account of the mutual correlation (the feedback) between the microscopic properties of molecules and the macrostate of the corresponding medium. This can be done via usage of the "enhanced" Hamilton operator of the considered many-particle system, which contains some temperature-dependent term(s), and the following introduction of the generalized equilibrium distribution over microstates. For illustration of the reasonableness of the proposed approach and of its practical availability in the applications to computing the macroscopic characteristics of condensed media, a cell model of melting/crystallization and metastable supercooled liquid for a water-like medium is presented.

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Alexandrov, Dmitri V., Alexander A. Ivanov et Irina V. Alexandrova. « Analytical solutions of mushy layer equations describing directional solidification in the presence of nucleation ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 376, n^o 2113 (8 janvier 2018) : 20170217. http://dx.doi.org/10.1098/rsta.2017.0217.

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The processes of particle nucleation and their evolution in a moving metastable layer of phase transition (supercooled liquid or supersaturated solution) are studied analytically. The transient integro-differential model for the density distribution function and metastability level is solved for the kinetic and diffusionally controlled regimes of crystal growth. The Weber–Volmer–Frenkel–Zel’dovich and Meirs mechanisms for nucleation kinetics are used. We demonstrate that the phase transition boundary lying between the mushy and pure liquid layers evolves with time according to the following power dynamic law: , where Z 1 ( t )= βt 7/2 and Z 1 ( t )= βt 2 in cases of kinetic and diffusionally controlled scenarios. The growth rate parameters α , β and ε are determined analytically. We show that the phase transition interface in the presence of crystal nucleation and evolution propagates slower than in the absence of their nucleation. This article is part of the theme issue ‘From atomistic interfaces to dendritic patterns’.

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Hrubý, Jan, Jiří Hykl, Pavel Peukert et Bohuslav Šmíd. « Experimental apparatus for measurement of density of supercooled water at high pressure ». EPJ Web of Conferences 25 (2012) : 01026. http://dx.doi.org/10.1051/epjconf/20122501026.

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Duki, Solomon F., et Mesfin Tsige. « Volume analysis of supercooled water under high pressure ». MRS Advances 3, n^o 41 (2018) : 2467–78. http://dx.doi.org/10.1557/adv.2018.426.

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ABSTRACTMotivated by an experimental finding on the density of supercooled water at high pressure [O. Mishima, J. Chem. Phys. 133, 144503 (2010)] we performed atomistic molecular dynamics simulations study of bulk water in the isothermal-isobaric ensemble. Cooling and heating cycles at different isobars and isothermal compression at different temperatures are performed on the water sample with pressures that range from 0 to 1.0 GPa. The cooling simulations are done at temperatures that range from 40 K to 380 K using two different cooling rates, 10 K/ns and 10 K/5 ns. For the heating simulations we used the slowest heating rate (10 K/5 ns) by applying the same range of isobars. Our analysis of the variation of the volume of the bulk water sample with temperature at different pressures from both isobaric cooling/heating and isothermal compression cycles indicates a concave-downward curvature at high pressures that is consistent with the experiment for emulsified water. In particular, a strong concave down curvature is observed between the temperatures 180 K and 220 K. Below the glass transition temperature, which is around 180 K at 1GPa, the volume turns to concave upward curvature. No crystallization of the supercooled liquid state was observed below 180 K even after running the system for an additional microsecond.

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Swenson, Jan. « Possible relations between supercooled and glassy confined water and amorphous bulk ice ». Physical Chemistry Chemical Physics 20, n^o 48 (2018) : 30095–103. http://dx.doi.org/10.1039/c8cp05688a.

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Mancinelli, R., F. Bruni et M. A. Ricci. « Controversial Evidence on the Point of Minimum Density in Deeply Supercooled Confined Water ». Journal of Physical Chemistry Letters 1, n^o 8 (30 mars 2010) : 1277–82. http://dx.doi.org/10.1021/jz100236j.

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Cui, Xiangda, Ahmed Bakkar et Wagdi George Habashi. « A multiphase SPH framework for supercooled large droplets dynamics ». International Journal of Numerical Methods for Heat & ; Fluid Flow 29, n^o 7 (1 juillet 2019) : 2434–49. http://dx.doi.org/10.1108/hff-10-2018-0547.

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Purpose This paper aims to introduce a three-dimensional smoothed particle hydrodynamics (SPH) framework for simulating supercooled large droplets (SLD) dynamics at aeronautical speeds. Design/methodology/approach To include the effects of the surrounding air, a multiphase model capable of handling high density-ratio problems is adopted. A diffusive term is incorporated to smooth the density field and avoid numerical instabilities. Additionally, a particle shifting technique is used to eliminate anisotropic particle distributions. Findings The framework is validated against low-speed droplet impingement experimental results and then applied to the droplet impingement at high speeds typical of SLD conditions. Preliminary parametric studies are conducted to investigate the post-impact splashing. It is observed that a thicker water film can decrease the crown diameter and a smaller impact angle can suppress upward and forward splashing. Originality/value A three-dimensional multiphase SPH framework for SLD dynamics at a wide range of impact speed is developed and validated. The effects of particle resolution, water film thickness and impact angle on the post-impact crown evolution are investigated.

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Singh, Lokendra P., Bruno Issenmann et Frédéric Caupin. « Pressure dependence of viscosity in supercooled water and a unified approach for thermodynamic and dynamic anomalies of water ». Proceedings of the National Academy of Sciences 114, n^o 17 (12 avril 2017) : 4312–17. http://dx.doi.org/10.1073/pnas.1619501114.

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The anomalous decrease of the viscosity of water with applied pressure has been known for over a century. It occurs concurrently with major structural changes: The second coordination shell around a molecule collapses onto the first shell. Viscosity is thus a macroscopic witness of the progressive breaking of the tetrahedral hydrogen bond network that makes water so peculiar. At low temperature, water at ambient pressure becomes more tetrahedral and the effect of pressure becomes stronger. However, surprisingly, no data are available for the viscosity of supercooled water under pressure, in which dramatic anomalies are expected based on interpolation between ambient pressure data for supercooled water and high pressure data for stable water. Here we report measurements with a time-of-flight viscometer down to 244K and up to 300MPa, revealing a reduction of viscosity by pressure by as much as 42%. Inspired by a previous attempt [Tanaka H (2000) J Chem Phys 112:799–809], we show that a remarkably simple extension of a two-state model [Holten V, Sengers JV, Anisimov MA (2014) J Phys Chem Ref Data 43:043101], initially developed to reproduce thermodynamic properties, is able to accurately describe dynamic properties (viscosity, self-diffusion coefficient, and rotational correlation time) as well. Our results support the idea that water is a mixture of a high density, “fragile” liquid, and a low density, “strong” liquid, the varying proportion of which explains the anomalies and fragile-to-strong crossover in water.

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N. Dubnishchev, Yu, V. A. Arbuzov, E. V. Arbuzov, V. S. Berdnikov, O. S. Melekhina, V. V. Sotnikov et A. A. Shibaev. « Hilbert diagnostics of convective structures and phase transition in super cooled water ». International Journal of Engineering & ; Technology 7, n^o 2.23 (20 avril 2018) : 295. http://dx.doi.org/10.14419/ijet.v7i2.23.12749.

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The evolution of the crystallization wave front and convective structures in a horizontal layer of supercooled water bounded by tempera- ture-controlled flat surfaces is visualized using methods of Hilbert optics. The phase transition is manifested by the occurrence of a crys- tallization wave and is accompanied by a positive energy release, which, in turn, affects the dynamic distribution of the optical phase density gradient in supercooled water and induces phase perturbations in the probing light field. The results of measurements of the phase velocity and the shape of the crystallization front approximated by Bezier curves are presented. The wave front velocity is obtained using modified time-of-fight method. The phase velocity field is found to exhibit spatio-temporal quasi-periodicity that can be related to the existence of oscillatory phenomena in the crystallization process.

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Mallamace, F., M. Broccio, C. Corsaro, A. Faraone, D. Majolino, V. Venuti, L. Liu, C. Y. Mou et S. H. Chen. « Evidence of the existence of the low-density liquid phase in supercooled, confined water ». Proceedings of the National Academy of Sciences 104, n^o 2 (27 décembre 2006) : 424–28. http://dx.doi.org/10.1073/pnas.0607138104.

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Hare, D. E., et C. M. Sorensen. « The density of supercooled water. II. Bulk samples cooled to the homogeneous nucleation limit ». Journal of Chemical Physics 87, n^o 8 (15 octobre 1987) : 4840–45. http://dx.doi.org/10.1063/1.453710.

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Stevens, C. L., N. J. Robinson, M. J. M. Williams et T. G. Haskell. « Observations of turbulence beneath sea ice in southern McMurdo Sound, Antarctica ». Ocean Science Discussions 6, n^o 2 (7 juillet 2009) : 1407–36. http://dx.doi.org/10.5194/osd-6-1407-2009.

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Abstract. The first turbulence profiler observations beneath land fast sea ice which is directly adjacent to an Antarctic ice shelf are described. The stratification in the 325 m deep water column consisted of a layer of supercooled water in the upper 40 m lying above a quasi-linearly stratified water column with a sharp step in density at mid-depth. Turbulent energy dissipation rates were on average 3×10−8 m2 s−3 with peak bin-averaged values reaching 4×10−7 m2 s−3. The local dissipation rate per unit area was estimated to be 10 mWm−2 on average with a peak of 50 mWm−2. These values are consistent with a moderate baroclinic response to the tides. The small-scale turbulent energetics lie on the boundary between isotropy and buoyancy-affected. This will likely influence the formation and aggregation of frazil ice crystals within the supercooled layer. An estimate of the vertical diffusivity of mass Kρ yields a coefficient of around 10−3 m2 s−1. Combining this estimate of Kρ with available observations of average and maximum currents suggests the layer of supercooled water can persist for a distance of ~20 km from the front of the McMurdo Ice Shelf.

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Gorfer, Alexander, Christoph Dellago et Marcello Sega. « High-density liquid (HDL) adsorption at the supercooled water/vapor interface and its possible relation to the second surface tension inflection point ». Journal of Chemical Physics 158, n^o 5 (7 février 2023) : 054503. http://dx.doi.org/10.1063/5.0132985.

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We investigate the properties of water along the liquid/vapor coexistence line in the supercooled regime down to the no-man’s land. Extensive molecular dynamics simulations of the TIP4P/2005 liquid/vapor interface in the range 198–348 K allow us to locate the second surface tension inflection point with a high accuracy at 283 ± 5 K, close to the temperature of maximum density. This temperature also coincides with the appearance of a density anomaly at the interface known as the apophysis. We relate the emergence of the apophysis to the observation of high-density liquid (HDL) water adsorption in the proximity of the liquid/vapor interface.

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Kringle, Loni, Wyatt A. Thornley, Bruce D. Kay et Greg A. Kimmel. « Isotope effects on the structural transformation and relaxation of deeply supercooled water ». Journal of Chemical Physics 156, n^o 8 (28 février 2022) : 084501. http://dx.doi.org/10.1063/5.0078796.

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We have examined the structure of supercooled liquid D2O as a function of temperature between 185 and 255 K using pulsed laser heating to rapidly heat and cool the sample on a nanosecond timescale. The liquid structure can be represented as a linear combination of two structural motifs, with a transition between them described by a logistic function centered at 218 K with a width of 10 K. The relaxation to a metastable state, which occurred prior to crystallization, exhibited nonexponential kinetics with a rate that was dependent on the initial structural configuration. When the temperature is scaled by the temperature of maximum density, which is an isostructural point of the isotopologues, the structural transition and the non-equilibrium relaxation kinetics of D2O agree remarkably well with those for H2O.

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Zhou, Si, S. Kim, Y. Hu, C. Berger, W. de Heer, Elisa Riedo et Angelo Bongiorno. « Thermo-chemical metastability of multilayer epitaxial graphene oxide : Experiments and density functional theory calculations ». MRS Proceedings 1451 (2012) : 39–44. http://dx.doi.org/10.1557/opl.2012.1453.

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ABSTRACTGraphene oxide holds great promise for future applications in nano-technology. The chemistry of this material is not well understood. This understanding is crucial to enable future applications of graphene oxide. In this study, experiments and density functional theory calculations are combined to elucidate the chemical properties of multilayer graphene oxide obtained by oxidizing epitaxial graphene grown on silicon carbide via the Hummers method. This study shows that at room temperature as prepared graphene oxide films exhibit a uniform and homogeneous structure, include a minimal amount of edges and holes, and have an oxidation ratio of about 0.44. The comparison with density-functional calculations shows that graphene oxide includes a minimal amount of intercalated water molecules and well-defined fractions of epoxide and hydroxyl groups.

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Corradini, D., M. Rovere et P. Gallo. « Structural Properties of High and Low Density Water in a Supercooled Aqueous Solution of Salt ». Journal of Physical Chemistry B 115, n^o 6 (17 février 2011) : 1461–68. http://dx.doi.org/10.1021/jp1101237.

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Cunsolo, Alessandro. « The THz Spectrum of Density Fluctuations of Water : The Viscoelastic Regime ». Advances in Condensed Matter Physics 2015 (2015) : 1–24. http://dx.doi.org/10.1155/2015/137435.

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Relevant advances in the knowledge of the water dynamics at mesoscopic scales are reviewed, while mainly focusing on the contribution provided by high resolution inelastic X-ray scattering (IXS). In particular it is discussed how the use of IXS has improved our understanding of viscoelastic properties of water at THz frequencies. This specifically involves some solid-like features such as the onset of shear wave propagation, a sound velocity surprisingly similar to the one of ice, and an anomalously low sound absorption coefficient. All these properties can be explained by assuming the coupling of THz density fluctuations with a structural relaxation process connected to the breaking and forming of hydrogen bonds (HBs). This review also includes more recent IXS results demonstrating that, upon approaching supercritical conditions, relaxation phenomena in water gradually lose their structural character becoming essentially collisional in character. Furthermore, GHz spectroscopy results on supercooled water, suggesting the occurrence of a structural arrest, are discussed. An overview of the new opportunities offered by next generation IXS spectrometers finally concludes this review.

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Madygulov, Marat Sh, Anatoliy N. Nesterov, Alexey M. Reshetnikov, Valeriy A. Vlasov et Alexey G. Zavodovsky. « Study of gas hydrate metastability and its decay for hydrate samples containing unreacted supercooled liquid water below the ice melting point using pulse NMR ». Chemical Engineering Science 137 (décembre 2015) : 287–92. http://dx.doi.org/10.1016/j.ces.2015.06.039.

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Naserifar, Saber, et William A. Goddard. « Liquid water is a dynamic polydisperse branched polymer ». Proceedings of the National Academy of Sciences 116, n^o 6 (24 janvier 2019) : 1998–2003. http://dx.doi.org/10.1073/pnas.1817383116.

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We developed the RexPoN force field for water based entirely on quantum mechanics. It predicts the properties of water extremely accurately, withTmelt= 273.3 K (273.15 K) and properties at 298 K: ΔHvap= 10.36 kcal/mol (10.52), density = 0.9965 g/cm3(0.9965), entropy = 68.4 J/mol/K (69.9), and dielectric constant = 76.1 (78.4), where experimental values are in parentheses. Upon heating from 0.0 K (ice) to 273.0 K (still ice), the average number of strong hydrogen bonds (SHBs, rOO≤ 2.93 Å) decreases from 4.0 to 3.3, but upon melting at 273.5 K, the number of SHBs drops suddenly to 2.3, decreasing slowly to 2.1 at 298 K and 1.6 at 400 K. The lifetime of the SHBs is 90.3 fs at 298 K, increasing monotonically for lower temperature. These SHBs connect to form multibranched polymer chains (151 H2O per chain at 298 K), where branch points have 3 SHBs and termination points have 1 SHB. This dynamic fluctuating branched polymer view of water provides a dramatically modified paradigm for understanding the properties of water. It may explain the 20-nm angular correlation lengths at 298 K and the critical point at 227 K in supercooled water. Indeed, the 15% jump in the SHB lifetime at 227 K suggests that the supercooled critical point may correspond to a phase transition temperature of the dynamic polymer structure. This paradigm for water could have a significant impact on the properties for protein, DNA, and other materials in aqueous media.

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Kringle, Loni, Wyatt A. Thornley, Bruce D. Kay et Greg A. Kimmel. « Structural relaxation and crystallization in supercooled water from 170 to 260 K ». Proceedings of the National Academy of Sciences 118, n^o 14 (31 mars 2021) : e2022884118. http://dx.doi.org/10.1073/pnas.2022884118.

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The origin of water’s anomalous properties has been debated for decades. Resolution of the problem is hindered by a lack of experimental data in a crucial region of temperatures, T, and pressures where supercooled water rapidly crystallizes—a region often referred to as “no man’s land.” A recently developed technique where water is heated and cooled at rates greater than 109 K/s now enables experiments in this region. Here, it is used to investigate the structural relaxation and crystallization of deeply supercooled water for 170 K < T < 260 K. Water’s relaxation toward a new equilibrium structure depends on its initial structure with hyperquenched glassy water (HQW) typically relaxing more quickly than low-density amorphous solid water (LDA). For HQW and T > 230 K, simple exponential relaxation kinetics is observed. For HQW at lower temperatures, increasingly nonexponential relaxation is observed, which is consistent with the dynamics expected on a rough potential energy landscape. For LDA, approximately exponential relaxation is observed for T > 230 K and T < 200 K, with nonexponential relaxation only at intermediate temperatures. At all temperatures, water’s structure can be reproduced by a linear combination of two, local structural motifs, and we show that a simple model accounts for the complex kinetics within this context. The relaxation time, τrel, is always shorter than the crystallization time, τxtal. For HQW, the ratio, τxtal/τrel, goes through a minimum at ∼198 K where the ratio is about 60.

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Zhao, Yan Chun, Rui Peng Mao, Wen Long Ma, Cong Yu Xu et Sheng Zhong Kou. « Microstructure and Corrosion Behavior of Ti-Ni Based Bulk Metallic Glass Composites ». Materials Science Forum 898 (juin 2017) : 666–71. http://dx.doi.org/10.4028/www.scientific.net/msf.898.666.

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In this study, (Ti0.5Ni0.5)80Cu20 metallic glass composites sample with 3mm diameter were prepared by levitation suspend melting-water cooled Cu mold process. Microstructure and thermodynamic behavior of the alloy were characterized by XRD, OM and DSC. the potention dynamic polarization curves in artificial seawater were tested by electrochemical workstation in a three-electrode system. The results showed that the as-cast microstructure of the alloy is consist of supercooled austenite phase, thermally-induced martensite phase and amorphous phase. Due to cooling rate, random dense pile of amorphous structure formed in surface of the alloy and supercooled austenite phase formed in interior. Besides, the alloy also presented excellent corrosion-resistance in artificial seawater for its higher corrosion potential (Ecorr) and polarization resistance (Rp), lower corrosion current density (Icorr) compared with Ti-6Al-4V(TC4) alloy.

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Stevens, C. L., N. J. Robinson, M. J. M. Williams et T. G. Haskell. « Observations of turbulence beneath sea ice in southern McMurdo Sound, Antarctica ». Ocean Science 5, n^o 4 (26 octobre 2009) : 435–45. http://dx.doi.org/10.5194/os-5-435-2009.

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Abstract. The first turbulence profiler observations beneath land fast sea ice which is directly adjacent to an Antarctic ice shelf are described. The stratification in the 325 m deep water column consisted of a layer of supercooled water in the upper 40 m lying above a quasi-linearly stratified water column with a sharp step in density at mid-depth. Turbulent energy dissipation rates were on average 3×10−8 m2 s−3 with peak bin-averaged values reaching 4×10−7 m2 s−3. The local dissipation rate per unit area was estimated to be 10 m Wm−2 on average with a peak of 50 m Wm−2. These values are consistent with a moderate baroclinic response to the tides. The small-scale turbulent energetics lie on the boundary between isotropy and buoyancy-affected. This will likely influence the formation and aggregation of frazil ice crystals within the supercooled layer. The data suggest that the large crystals observed in McMurdo Sound will transition from initial growth at scales smaller than the Kolmogorov lengthscale to sizes substantially (1–2 orders of magnitude) greater than the Kolmogorov scale. An estimate of the experiment-averaged vertical diffusivity of mass Kρ yields a coefficient of around 2×10−4 m2s−1 although this increased by a factor of 2 near the surface. Combining this estimate of Kρ with available observations of average and maximum currents suggests the layer of supercooled water can persist for a distance of ~250 km from the front of the McMurdo Ice Shelf.

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Tang, Ping-Han, et Ten-Ming Wu. « Instantaneous normal mode analysis for OKE reduced spectra of liquid and supercooled water : Contributions of low-density and high-density liquids ». Journal of Molecular Liquids 301 (mars 2020) : 112363. http://dx.doi.org/10.1016/j.molliq.2019.112363.

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Handle, Philip H., Thomas Loerting et Francesco Sciortino. « Supercooled and glassy water : Metastable liquid(s), amorphous solid(s), and a no-man’s land ». Proceedings of the National Academy of Sciences 114, n^o 51 (13 novembre 2017) : 13336–44. http://dx.doi.org/10.1073/pnas.1700103114.

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We review the recent research on supercooled and glassy water, focusing on the possible origins of its complex behavior. We stress the central role played by the strong directionality of the water–water interaction and by the competition between local energy, local entropy, and local density. In this context we discuss the phenomenon of polyamorphism (i.e., the existence of more than one disordered solid state), emphasizing both the role of the preparation protocols and the transformation between the different disordered ices. Finally, we present the ongoing debate on the possibility of linking polyamorphism with a liquid–liquid transition that could take place in the no-man’s land, the temperature–pressure window in which homogeneous nucleation prevents the investigation of water in its metastable liquid form.

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Гурулев, А. А., et А. О. Орлов. « Проявление линии Видома при микроволновых измерениях увлажненных перекисью водорода сорбентов ». Письма в журнал технической физики 48, n^o 2 (2022) : 41. http://dx.doi.org/10.21883/pjtf.2022.02.51921.18995.

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For deeply supercooled bulk water, anomalies of thermodynamic values are known near the Widom line, the locus of increased fluctuations of entropy and density. In this work, we measured the reflected power of microwave radiation at a frequency of 18 GHz from a silicate sorbent sample moistened with a hydrogen peroxide solution. In the experiment, we observed variations in the recorded reflected radiation power in the range –46 – –47 °С, determined by structural changes in the liquid. Thus, it is shown that fluctuations of water parameters near the Widom line are manifested in changes not only in thermodynamic, but also in electrophysical quantities.

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Gartner, Thomas E., Linfeng Zhang, Pablo M. Piaggi, Roberto Car, Athanassios Z. Panagiotopoulos et Pablo G. Debenedetti. « Signatures of a liquid–liquid transition in an ab initio deep neural network model for water ». Proceedings of the National Academy of Sciences 117, n^o 42 (2 octobre 2020) : 26040–46. http://dx.doi.org/10.1073/pnas.2015440117.

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The possible existence of a metastable liquid–liquid transition (LLT) and a corresponding liquid–liquid critical point (LLCP) in supercooled liquid water remains a topic of much debate. An LLT has been rigorously proved in three empirically parametrized molecular models of water, and evidence consistent with an LLT has been reported for several other such models. In contrast, experimental proof of this phenomenon has been elusive due to rapid ice nucleation under deeply supercooled conditions. In this work, we combined density functional theory (DFT), machine learning, and molecular simulations to shed additional light on the possible existence of an LLT in water. We trained a deep neural network (DNN) model to represent the ab initio potential energy surface of water from DFT calculations using the Strongly Constrained and Appropriately Normed (SCAN) functional. We then used advanced sampling simulations in the multithermal–multibaric ensemble to efficiently explore the thermophysical properties of the DNN model. The simulation results are consistent with the existence of an LLCP, although they do not constitute a rigorous proof thereof. We fit the simulation data to a two-state equation of state to provide an estimate of the LLCP’s location. These combined results—obtained from a purely first-principles approach with no empirical parameters—are strongly suggestive of the existence of an LLT, bolstering the hypothesis that water can separate into two distinct liquid forms.

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Farzaneh, M., et J. L. LaForte. « The Effect of Voltage Polarity on Ice Accretions on Short String Insulators ». Journal of Offshore Mechanics and Arctic Engineering 113, n^o 2 (1 mai 1991) : 179–84. http://dx.doi.org/10.1115/1.2919915.

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The present study investigated the effect of voltage polarity on ice deposits accumulated on a short-string of porcelain insulators from 85 μm supercooled droplets in a cold room maintained at a temperature of −12°C. The air velocity and the liquid water content were 3.3 m/s and 2.0 g/m3, respectively. Under these growth conditions, the type of ice accretion was hard rime with a density of 0.87 g/cm3 and the highest probability of flashover occurrence. With an applied voltage of 15 kV per insulator unit, corresponding to the operational voltage in service, there were no major changes in weight, density or the texture of the ice grown on the surface of the insulators.

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Khan, Arshad. « A Liquid Water Model : Density Variation from Supercooled to Superheated States, Prediction of H-Bonds, and Temperature Limits ». Journal of Physical Chemistry B 104, n^o 47 (novembre 2000) : 11268–74. http://dx.doi.org/10.1021/jp0016683.

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Bulone, D., I. D. Donato, M. B. Palma‐Vittorelli et M. U. Palma. « Density, structural lifetime, and entropy of H‐bond cages promoted by monohydric alcohols in normal and supercooled water ». Journal of Chemical Physics 94, n^o 10 (15 mai 1991) : 6816–26. http://dx.doi.org/10.1063/1.460260.

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Hernandes, V. F., M. S. Marques et José Rafael Bordin. « Phase classification using neural networks : application to supercooled, polymorphic core-softened mixtures ». Journal of Physics : Condensed Matter 34, n^o 2 (28 octobre 2021) : 024002. http://dx.doi.org/10.1088/1361-648x/ac2f0f.

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Abstract Characterization of phases of soft matter systems is a challenge faced in many physical chemical problems. For polymorphic fluids it is an even greater challenge. Specifically, glass forming fluids, as water, can have, besides solid polymorphism, more than one liquid and glassy phases, and even a liquid–liquid critical point. In this sense, we apply a neural network algorithm to analyze the phase behavior of a mixture of core-softened fluids that interact through the continuous-shouldered well (CSW) potential, which have liquid polymorphism and liquid–liquid critical points, similar to water. We also apply the neural network to mixtures of CSW fluids and core-softened alcohols models. We combine and expand methods based on bond-orientational order parameters to study mixtures, applied to mixtures of hardcore fluids and to supercooled water, to include longer range coordination shells. With this, the trained neural network was able to properly predict the crystalline solid phases, the fluid phases and the amorphous phase for the pure CSW and CSW-alcohols mixtures with high efficiency. More than this, information about the phase populations, obtained from the network approach, can help verify if the phase transition is continuous or discontinuous, and also to interpret how the metastable amorphous region spreads along the stable high density fluid phase. These findings help to understand the behavior of supercooled polymorphic fluids and extend the comprehension of how amphiphilic solutes affect the phases behavior.

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Gurulev A. A. et Orlov A. O. « Manifestation of the Widom line in microwave measurements of sorbents moistened with hydrogen peroxide ». Technical Physics Letters 48, n^o 1 (2022) : 81. http://dx.doi.org/10.21883/tpl.2022.01.52478.18995.

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For deeply supercooled bulk water, known are anomalies of thermodynamic quantities near the Widom line, the locus of increased fluctuations of entropy and density. In this work, we measured the reflected power of microwave radiation at the frequency of 18 GHz from a silicate sorbent sample moistened with a hydrogen peroxide solution. In the experiment, we observed variations in the recorded reflected radiation power in the range of -46 to -47oC determined by structural changes in the liquid. Thus, it is shown that fluctuations of water parameters near the Widom line manifest themselves in changes not only in thermodynamic, but also in electrophysical quantities. Keywords: Widom line, second critical point, nanoporous materials, hydrogen peroxide, microwaves.

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Paschek, Dietmar, Andreas Rüppert et Alfons Geiger. « Thermodynamic and Structural Characterization of the Transformation from a Metastable Low-Density to a Very High-Density Form of Supercooled TIP4P-Ew Model Water ». ChemPhysChem 9, n^o 18 (26 novembre 2008) : 2737–41. http://dx.doi.org/10.1002/cphc.200800539.

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Zawadzki, I., W. Szyrmer, C. Bell et F. Fabry. « Modeling of the Melting Layer. Part III : The Density Effect ». Journal of the Atmospheric Sciences 62, n^o 10 (1 octobre 2005) : 3705–23. http://dx.doi.org/10.1175/jas3563.1.

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Abstract A model of the melting snow and its radar reflectivity is presented here. The main addition to previous description of the melting layer is the explicit introduction of snow density as a variable. The model is validated with radar observations. Differences in brightband intensity for comparable precipitation rates are related here to the coexistence of supercooled cloud water (SCW) with snow above the melting level leading to riming and change in snow density. Cases where riming was suspected were selected according to the characteristics of the vertical profile of reflectivity flux above the melting layer and vertical Doppler velocities faster than expected from low-density snow. For stratiform precipitation with a melting layer, high snow-to-rain velocity ratio indicates high-density snow and consequently a small peak-to-rain reflectivity difference is expected. This relationship was computed from the model and confirmed with vertically pointing radar observations. In spite of the complexity of the physical processes present in the melting layer the model appears to capture the essential elements.

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Price, William S., Hiroyuki Ide, Yoji Arata et Masaya Ishikawa. « Visualisation of Freezing Behaviours in Flower Bud Tissues of Cold-hardy Rhododendron japonicum by Nuclear Magnetic Resonance Micro-Imaging ». Functional Plant Biology 24, n^o 5 (1997) : 599. http://dx.doi.org/10.1071/pp97049.

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1H nuclear magnetic resonance (NMR) micro-imaging was used to study the freezing behaviour of wintering flower buds of Rhododendron japonicum (A. Gray) Suringer. Amulti-slice multi- echo pulse sequence was used to acquire images at different subfreezing temperatures. The images obtained predominantly reflected the density of mobile (i.e. non-ice) protons mainly from unfrozen water. By comparing these images taken at various subfreezing temperatures, we could determine which tissues produced high temperature exotherms and low temperature exotherms in differential thermal analyses. In flower buds of the cold-hardy R. japonicum, typical extra-organ freezing was successfully imaged. The scales readily froze at –7°C but some florets remained supercooled even at –21°C. The size of the supercooled florets was reduced with decreasing temperature which indicated a gradual decrease in floret water content. With decreasing temperature, there was a gradual decrease in the signal intensity of the flower bud axis including the peduncle and immature pith tissues, which implies either dehydration or partial freezing of these tissues. Deep supercooling in the entire mature pith tissues was also clearly visible in these images. Due to its non-invasive nature, NMR micro-imaging is a useful tool for studying freezing behaviours in various plant tissues, especially for imaging organised or harmonised freezing in complex organs as well as for clarifying the diversity and mechanisms involved in freezing behaviours.

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Jones, Kathleen F., Gregory Thompson, Keran J. Claffey et Eric P. Kelsey. « Gamma Distribution Parameters for Cloud Drop Distributions from Multicylinder Measurements ». Journal of Applied Meteorology and Climatology 53, n^o 6 (juin 2014) : 1606–17. http://dx.doi.org/10.1175/jamc-d-13-0306.1.

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AbstractThe liquid water content and drop diameters in supercooled clouds have been measured since the 1940s at the summit of Mount Washington in New Hampshire using a rotating multicylinder. Many of the cloud microphysics models in the Weather Research and Forecasting Model (WRF) assume a gamma distribution for cloud drops. In this paper, years of multicylinder data are reanalyzed to determine the best-fitting gamma or monodisperse distribution to compare with parameters in the WRF cloud models. The single-moment cloud schemes specify a predetermined and constant drop number density in clouds, which leads to a fixed relationship between the median volume drop diameter and the liquid water content. The Mount Washington drop number densities are generally larger and best-fit distributions are generally narrower than is typically assumed in WRF.

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