Constraining the olivine amount and water content at 410-km discontinuity with the elasticity of wadsleyite and olivine

<p>The water content in the mantle transition zone exerts a controlling influence on the dynamical and chemical evolution of Earth, but is poorly known. In principle the water content at the top of the transition zone can be inferred by comparing the velocity and density contrasts across the 410-km seismic discontinuity with predictions based on the phase transition of olivine to wadsleyite. The high-quality elastic data of at pressure and temperature (PT) conditions of the transition zone are crucial but are very challenge for experiments to obtain. Calculating these elastic data at high PT conditions in conventional method are also very expensive. Instead, these elastic data were calculated using the method of Wu and Wentzcovitch (2011), which reduces the computational workload to tenth of the conventional method. All calculations for two phases were conducted using the same computational details as far as possible, which guarantees that the velocity and density differences between two phases have very high precise. All these calculated elastic data agree well with the available experimental data. The iron and water effect on the elasticity are also well described.</p><p>With these high-quality elastic data covered the PT condition of the transition zone, we analyze the water and wadsleyite content at the top of the transition zone. We found that the water content of wadsleyite at the top of the transition zone can be well constrained when density and velocities jumps are considered together. For a pyrolitic mantle composition with ~60% olivine, our best fit is ~ 0.5 wt% water at the top of the transition zone. If the transition zone is dry, as suggested by some electrical conductivity models, the upper mantle may only contain ~ 50% olivine (Wang et al., 2019).</p><p> </p><p>Wang, W-Z., Walter, M.J., Peng, Y., Redfern, S., Wu, Z-Q., 2019a. Constraining olivine abundance and water content of the mantle at the 410-km discontinuity from the elasticity of olivine and wadsleyite. Earth Planet. Sci. Lett. 519, 1–11.</p><p>Wu, Z-Q., Wentzcovitch, R.M., 2011. Quasiharmonic thermal elasticity of crystals: An analytical approach. Phys. Rev. B - Condens. Matter Mater. Phys. 83, 1–8. doi:10.1103/PhysRevB.83.184115</p><p> </p>

Формирование тонких пленок соединений Cu2SnS3 и Cu2SnSe3

Показана возможность синтеза соединений Cu2SnS3 и Cu2SnSe3 на стеклянных подложках путём отжига в парах халькогена тонкой металлической плёнки сплава Cu:Sn = 2:1 в вакуумной графитовой камере типа квазизамкнутого объёма. Методом рентгеновской дифракции установлено, что полученные плёнки халькогенидов имеют подобную сфалериту кристаллическую структуру. Для кубической модификации Cu2SnS3 и Cu2SnSe3 преимущественными плоскостями отражений являются (111), (220) и (311). Элементный состав плёнок соответствует стехиометрии соединений Cu2SnS3 и Cu2SnSe3. Методом ИК-спектроскопии определены энергии активации прямозонных переходов для Cu2SnS3 – 0.96 eV, а для Cu2SnSe3 – 0.70 eV. ИСТОЧНИК ФИНАНСИРОВАНИЯ Работа выполнена при финансовой поддержке гранта РФФИ № 18-32-00971 – мол_а. ЛИТЕРАТУРА Milichko V. A., Shalin A. S., Mukhin I. S., et al. Usp., 2016, vol. 59, pp. 727–772. https://doi.org/10.3367/ufne.2016.02.037703 Wesley Herche. Renewable and Sustainable Energy Reviews, 2017, vol. 77, pp. 590-595. https://doi.org/10.1016/j.rser.2017.04.028 Rujun Suna, Daming Zhuang, Ming Zhao, et al. Solar Energy Materials and Solar Cells, 2018, vol. 174, pp. 42–49. https://doi.org/10.1016/j.solmat.2017.08.011 Orletskii I. G., Mar’yanchuk P. D., Solovan M. N., et al. Physics of the Solid State, 2016. vol. 58, no. 5, pp. 1058-1064. https://doi.org/10.1134/s1063783416050188 Ren Y. Acta Universitatis Upsaliensis, Uppsala, 2017, 85 p. URL: https://uu.diva-portal.org/smash/get/diva2:1072439/FULLTEXT01.pdf Lokhande A. C. Solar Energy Materials and Solar Cells, August 2016, vol. 153, pp. 84-107. https://doi.org/10.1016/j.solmat.2016.04.003 Shelke H. D., Lokhande A. C., Patil A. M., et al. Surfaces and Interfaces, 2017, vol. 9, pp. 238-244. https://doi.org/10.1016/j.surfin.2017.08.006 Orletskii I. G., Solovan M. N., Pinna F., et al. Physics of the Solid State. 2017, vol. 59, no. 4, pp. 801-807. https://doi.org/10.1134/s1063783417040163 Mingrui He. Journal of Alloys and Compounds, April 2017, vol. 701, pp. 901-908. https://doi.org/10.1016/j.jallcom.2017.01.191 Pin-Wen, GuanShun-Li Shang, Greta Lindwall. Solar Energy, 2017, vol. 155, pp. 745-757. https://doi.org/10.1016/j.solener.2017.07.017 Ju Yeon Lee. Solar Energy, 2017, vol. 145, pp. 27-32. https://doi.org/10.1016/j.solener.2016.09.041 Subbotina, O. Y., Kishkoparov N. V., Frishberg I. V. High Temperature, 1999, vol. 37, no. 2, pp. 198–203. URL: http://www.mathnet.ru/php/archive.phtml?wshow=paper&jrnid=tvt&paperid=2266&option_lang=rus (in Russ.) Budanov A. V., Vlasov Yu. N., Grechkina M. V., et al. Condensed Matter and Interphases, 2016, vol. 18, no. 4, pp. 481–486. URL: http://www.kcmf.vsu.ru/resources/t_18_4_2016_004.pdf (in Russ.) Zhang, Huang L. L., Zhu X. G., et al. Scripta Materialia, 2019, vol. 159, pp. 46–50. https://doi.org/10.1016/j.scriptamat.2018.09.010 Lukashev P., Lambrecht W. R. L., Kotani T., Schilfgaarde M. Rev. B: Condens. Matter Mater. Phys., 2007, vol. 76, p. 195202. https://doi.org/10.1103/physrevb.76.195202

Wounds like flowers opening: a discussion of Hysteria for trombone and four-channel tape

In this paper I discuss Hysteria, a work for trombone and four-channel tape. Abbie Conant, an internationally reco gnised trombonist, commissioned and performed Hysteria as part of her ‘Wired Goddess’ project. I chose five lines of poetry from John Campion's Tongue Stones: ‘matter/mater/meter/muthos’, ‘bowl of regeneration/quickener of wombs’, ‘follow the mysteries of your feet’, ‘Let dark ages be crucibles’ and ‘wounds like flowers opening’. With this text I created an implex of sonic images relating the body, fertility, menses and violence. The first line is particularly important and shapes the first two-thirds of the piece. The musical material complements the text and uses periodicity to suggest the body's heartbeat and breath. The heartbeat serves as a cantus firmus, occurring every five seconds, and pedal tones form the primary material for the trombone part and connect to the idea of breath. The punctuating gunshots occurring in the first half imply violence, and the dark red lighting suggests blood. The tape and trombone intertwine in a sonic world evoking the womb and regeneration. The four-channel tape heightens the sense of immersion that connected to the piece's resonance and dream-like atmosphere. The web of these associations constitutes an artistic reflection on the sensibility and experience of the feminine in a patriarchal society.

Frustrated order by disorder: The pyrochlore anti-ferromagnet with bond disorder

The classical Heisenberg anti-ferromagnet on the pyrochlore lattice is macroscopically and continuously degenerate and the system remains disordered at all temperatures, even in the presence of weak dilution with nonmagnetic ions. We show that, in contrast, weak-bond disorder lifts the ground-state degeneracy in favour of locally collinear spin configurations. We present a proof that for a single tetrahedron the ground state is perfectly collinear but identify two mechanisms that preclude the establishment of a globally collinear state; one due to frustration and the other due to higher order effects. We thus obtain a rugged energy landscape, which is necessary to account for the glassy phenomena found in real systems such as the pyrochlore Y2Mo2O7 recently reported by Booth et al. (Phys. Rev. B: Condens. Matter Mater. Phys. 62, R755 (2000).) to contain a substantial degree of bond disorder. PACS Nos.: 75.10.Hk, 75.40.Mg, 75.40.Gb