نتایج جستجو برای: diamonds

تعداد نتایج: 1532  

2005
J. Andrew Grant

This article examines the external and internal dimensions of post-conflict reconstruction in Sierra Leone. The United Nations, bilateral donors such as the United Kingdom, and transnational non-governmental organizations and aid agencies have been instrumental in providing much-needed external assistance to Sierra Leone during the latter stages of its civil war and in the immediate post-war pe...

2018
Ming Chen Jinfu Shu Xiande Xie Dayong Tan Ho-kwang Mao

Formation of natural diamonds requires the reduction of carbon to its bare elemental form, and pressures (P) greater than 5 GPa to cross the graphite-diamond transition boundary. In a study of shocked ferromagnesian carbonate at the Xiuyan impact crater, we found that the impact pressure-temperature (P-T) of 25-45 GPa and 800-900 °C were sufficient to decompose ankerite Ca(Fe2+,Mg)(CO3)2 to for...

2017
Fumiya Maeda Eiji Ohtani Seiji Kamada Tatsuya Sakamaki Naohisa Hirao Yasuo Ohishi

Diamond is an evidence for carbon existing in the deep Earth. Some diamonds are considered to have originated at various depth ranges from the mantle transition zone to the lower mantle. These diamonds are expected to carry significant information about the deep Earth. Here, we determined the phase relations in the MgCO3-SiO2 system up to 152 GPa and 3,100 K using a double sided laser-heated di...

2010
Earl H. McKinney

A generalized recursive interpolation technique for a set of linear functionals over a set of general univariate basis functions has been previously developed. This paper extends these results to restricted multivariate interpolation over a set of general multivariate basis functions. When the data array is a suitable configuration (e.g., an ^-dimensional simplex), minimal degree multivariate i...

2011
Elke Neu David Steinmetz Janine Riedrich-Möller Stefan Gsell Martin Fischer Matthias Schreck Christoph Becher

We introduce a process for the fabrication of high-quality, spatially isolated nano-diamonds on iridium via microwave-plasma-assisted chemical vapour deposition (CVD) growth. We perform spectroscopy of single siliconvacancy (SiV) centres produced during the growth of the nano-diamonds. The colour centres exhibit extraordinary narrow zero-phonon-lines down to 0.7 nm at room temperature. Single p...

2013
D Bischoff A Varlet P Simonet T Ihn K Ensslin

A quantum dot has been etched in bilayer graphene connected by two small constrictions to the leads. We show that this structure does not behave like a single quantum dot but consists of at least three sites of localized charge in series. The high symmetry and electrical stability of the device allowed us to triangulate the positions of the different sites of localized charge and find that one ...

2007
James Propp Richard Stanley

In this paper, we continue the study of domino-tilings of Aztec diamonds (introduced in [1] and [2]). In particular, we look at certain ways of placing “barriers” in the Aztec diamond, with the constraint that no domino may cross a barrier. Remarkably, the number of constrained tilings is independent of the placement of the barriers. We do not know of a simple combinatorial explanation of this ...

Journal: :Scientific American 1906

Journal: :Proceedings of the National Academy of Sciences 2020

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