10,348 research outputs found
Proper Ferroelectricity in the Dion?Jacobson Material CsBi2Ti2NbO10: Experiment and Theory
No full textA diverse range of materials and properties are exhibited by layered perovskites. We report on the synthesis, characterization, and computational investigation of a new ferroelectric?CsBi2Ti2NbO10, an n = 3 member of the Dion?Jacobson (DJ) family. Structural studies using variable temperature neutron powder diffraction indicate that a combination of octahedral rotations and polar displacements result in the polar structure. Density functional theory calculations reveal that the wider perovskite blocks in CsBi2Ti2NbO0 stabilize proper ferroelectricity, in contrast to the hybrid-improper ferroelectricity reported for all other DJ phases. Our results raise the possibility of a new class of proper ferroelectric materials analogous to the well-known Aurivillius phases
Howard N. Jacobson Oral History Interview
No full textCharles Mahan records an oral history on Howard N. Jacobson, M.D. from notes taken on weekly visits to him at his home in Plant City in the first five months of the year 2015. Mahan speaks on Jacobson’s education in Minnesota and his subsequent service in the Navy, as well as many of Jacobson’s accomplishments and life history. Particular notes of interest are Jacobson’s fondest memories in the Chicago Maternity Center, his time spent at Harvard, and Jacobson’s observations on many medical approaches to various conditions from cancer prevention to autism
The Jacobson radical of rings with nilpotent homogeneous elements
No full textA result of Bergman says that the Jacobson radical of a graded algebra is homogeneous. It is shown that while graded Jacobson radical algebras have homogeneous elements nilpotent, it is not the case that graded algebras all of whose homogeneous elements are nilpotent are Jacobson radical. To contrast this, the following result of the author is slightly extended. Let R be a graded algebra generated in the degree one. If for every n, the n x n matrix algebra over R has all homogeneous elements nilpotent, then R is Jacobson radical.</p
Labidostomis (Labidostomis) tjutschewi Jacobson 1902
No full textLabidostomis (Labidostomis) tjutschewi Jacobson, 1902 References. Jacobson 1902: 75; Guselnikov and Medvedev 1984: 18; Warchalowski 1985: 729; Yanovsky 1996: 33. Distribution. Asian Russia (Tuva, Khakassia, Transbaikalia), N Mongolia. Material Examined. Sartachul, 28.vi.1988, 2 ex. (V. Yanovsky) (IFK); Akademgorodok, 5.vi.2003, 17.vi.2012, 16 1♀ (E. Akulov) (EACK); Stolby Nature Sanctuary, 5.vi.2011, 30.vi.2011, 17.vi.2014 26 2♀ (E. Akulov) (EACK); Minusinsk, 10.vi.2011, 16 1♀ (E. Akulov) (EACK); Berezovsky, 24. vii.2011, 16 1♀ (E. Akulov) (EACK); Znamenka, 6. vii.2012, 2♀ (E. Akulov) (EACK); Krasnoyarsk, 2. vii.2014, 36 (E. Akulov) (EACK). Notes. Type locality: Uzun-Zhul tributary of the Abakan (Minusinsk Hollow). Described from a series of syntypes from the collections of A. Jacobson (Jacobson 1902).Published as part of Guskova, Elena V., Akulov, Evgeny N. & Loshchev, Sergey M., 2018, The Cryptocephalinae (Coleoptera: Chrysomelidae) of the Krasnoyarsk Krai (except for the Taymyrsky Dolgano-Nenetsky District), Siberia, Russia, pp. 565-576 in The Coleopterists Bulletin 72 (3) on page 569, DOI: 10.1649/0010-065X-72.3.565, http://zenodo.org/record/538417
Cryptocephalus (Cryptocephalus) krutovskii Jacobson 1901
No full textCryptocephalus (Cryptocephalus) krutovskii Jacobson, 1901 References. Medvedev 1973: 119 (southern Krasnoyarsk Krai (Uzun-Zhul tributary of the Abakan)). However, Medvedev attributed the type locality to southern Krasnoyarsk Krai;, in fact, it is Khakassia. Distribution. Asian Russia (Krasnoyarsky Krai (new record), Altais, Tuva, Sayans, Middle Siberia, S Yakutia, Far East), Mongolia, Japan. Material Examined. Stolby Nature Sanctuary, 15.vi.2017, 16 2♀ (E. Akulov) (EACK). Notes. Type locality: Uzun-Zhul tributary of the Abakan (Minusinsk Hollow). Described from the collections of A. Jacobson (Jacobson 1901).Published as part of Guskova, Elena V., Akulov, Evgeny N. & Loshchev, Sergey M., 2018, The Cryptocephalinae (Coleoptera: Chrysomelidae) of the Krasnoyarsk Krai (except for the Taymyrsky Dolgano-Nenetsky District), Siberia, Russia, pp. 565-576 in The Coleopterists Bulletin 72 (3) on page 572, DOI: 10.1649/0010-065X-72.3.565, http://zenodo.org/record/538417
Formamidinium-Based Dion-Jacobson Layered Hybrid Perovskites: Structural Complexity and Optoelectronic Properties
No full textLayered hybrid perovskites have emerged as a promising alternative to stabilizing hybrid organic–inorganic perovskite materials, which are predominantly based on Ruddlesden-Popper structures. Formamidinium (FA)-based Dion-Jacobson perovskite analogs are developed that feature bifunctional organic spacers separating the hybrid perovskite slabs by introducing 1,4-phenylenedimethanammonium (PDMA) organic moieties. While these materials demonstrate competitive performances as compared to other FA-based low-dimensional perovskite solar cells, the underlying mechanisms for this behavior remain elusive. Here, the structural complexity and optoelectronic properties of materials featuring (PDMA)FAn–1PbnI3n+1 (n = 1–3) formulations are unraveled using a combination of techniques, including X-ray scattering measurements in conjunction with molecular dynamics simulations and density functional theory calculations. While theoretical calculations suggest that layered Dion-Jacobson perovskite structures are more prominent with the increasing number of inorganic layers (n), this is accompanied with an increase in formation energies that render n > 2 compositions difficult to obtain, in accordance with the experimental evidence. Moreover, the underlying intermolecular interactions and their templating effects on the Dion-Jacobson structure are elucidated, defining the optoelectronic properties. Consequently, despite the challenge to obtain phase-pure n > 1 compositions, time-resolved microwave conductivity measurements reveal high photoconductivities and long charge carrier lifetimes. This comprehensive analysis thereby reveals critical features for advancing layered hybrid perovskite optoelectronics.</p
El desplazamiento de los pueblos indígenas y cimarrones en Surinam propiciado por el Estado y empresas mineras: Casos de los pueblos Kaliña, N´djuka y Saramaka
No full text“En este trabajo se explora la importancia del reconocimiento de estos tres pueblos como entidades jurídicas en la Constitución y la relevancia de crear políticas públicas para el desarrollo social, económico y político de los Kaliña, N´djuka y Saramaka esto con el fin de mitigar los desplazamientos.
Studio portrait, Herald Jacobson
No full textJacobson, Herald. "Athletic Dept. Portraits - 3x5. Track Men." The negative includes a head and chest portrait of Herald Jacobson wearing a tank top with an "N" on it and a posed action shot of him ready to race (front view.) He has a patch taped to one of his arms
Jacobson (Yoram) La Pensée hassidique
No full textAzria Régine. Jacobson (Yoram) La Pensée hassidique. In: Archives de sciences sociales des religions, n°70, 1990. p. 277
Energi Laplacian Dari Graf Jacobson Atas Ring Zn
No full textGraf Jacobson adalah graf yang dikonstruksi atas sebuah ring berhingga yang komutatif. Himpunan titik dari graf Jacobson adalah elemen-elemen dari ring yang bukan merupakan elemen dari Jacobson radical, sedangkan himpunan sisinya berisi pasangan titik yang memiliki sifat tertentu yang terkait dengan himpunan unit. Tujuan dari penelitian ini adalah mengkonstruksi graf Jacobson atas ring ℤn serta menentukan energi dan energi Laplacian dari grafnya. Dengan menggunakan sifat elemen pada ring Zn, dapat dikonstruksi graf Jacobson atas ring Zn, untuk beberapa kondisi n
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