The story of one diamond: the heterogeneous distribution of the optical centres within a diamond crystal from the Ichetju placer, northern Urals

2019 ◽  
Vol 83 (4) ◽  
pp. 515-522
Author(s):  
Evgeny Vasilev ◽  
Vitaly Petrovsky ◽  
Alexander Kozlov ◽  
Anton Antonov ◽  
Andrey Kudryavtsev ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Diamond Crystal ◽  
Outer Part ◽  
Heterogeneous Distribution ◽  
The Core ◽  
Specific Shape ◽  
Full Conversion ◽  
Bright Blue ◽  
Growth Diffusion ◽  
Dark Core

AbstractWe have investigated a diamond crystal that consists of several misorientated subgrains. The main feature of the crystal is the dark areas in the cathodoluminescent core that has ‘estuary-like’ boundaries extending along the subgrain interfaces. The core has >3100 ppm of nitrogen, and the share of the B form is >95%; the absorbance of the centre N3VH at 3107 cm–1 reaches 75 cm–1. The N3 centre absorbance, as well as N3 luminescence, is absent in the core. In the outer part of the crystal, bright blue luminescence of the N3 centre is apparent, and the N3 absorbance reaches 5.3 cm–1. These observations could be explained by the conversion of N3 centres to N3VH after attaching a hydrogen atom. After the full conversion of the N3 centres, the diamond becomes darker under CL. We hypothesise the dark core has a specific shape due to the post-growth diffusion of the hydrogen.

The westward drift of the Earth's magnetic field

1950 ◽  
Vol 243 (859) ◽  
pp. 67-92 ◽  
Keyword(s):  
Magnetic Field ◽  
Secular Variation ◽  
Outer Part ◽  
Earth’S Magnetic Field ◽  
Dynamo Theory ◽  
The Core ◽  
The Earth ◽  
Earth's Magnetic Field ◽  
Harmonic Analyses ◽  
Westward Drift

The westward drift of the non-dipole part of the earth’s magnetic field and of its secular variation is investigated for the period 1907-45 and the uncertainty of the results discussed. It is found that a real drift exists having an angular velocity which is independent of latitude. For the non-dipole field the rate of drift is 0.18 ± 0-015°/year, that for the secular variation is 0.32 ±0-067°/year. The results are confirmed by a study of harmonic analyses made between 1829 and 1945. The drift is explained as a consequence of the dynamo theory of the origin of the earth’s field. This theory required the outer part of the core to rotate less rapidly than the inner part. As a result of electromagnetic forces the solid mantle of the earth is coupled to the core as a whole, and the outer part of the core therefore travels westward relative to the mantle, carrying the minor features of the field with it.

Formation and Properties of Iron-Phosphorus and Iron-Phosphorus-Hydrogen Complexes in Silicon

2005 ◽  
Vol 108-109 ◽  
pp. 379-384 ◽  
Author(s):  
Teimuraz Mchedlidze
Keyword(s):  
Hydrogen Atom ◽  
Hyperfine Structure ◽  
Spin State ◽  
Iron Atom ◽  
Phosphorus Atom ◽  
The Core ◽  
Hydrogen Deuterium ◽  
Phosphorus Iron ◽  
Related Defect ◽  
Isotope Content

Hitherto unreported ESR signal, labeled TU10, was detected after annealing of electronirradiated silicon samples doped with phosphorus, iron and hydrogen. The ESR spectrum corresponds to a complex having monoclinic-I symmetry and S = 3/2 spin-state. Hyperfine structure of the TU10 spectrum suggests participation of two nucleus with spin I = 1/2 and 100% abundance in the core of the related defect. Doping of samples with hydrogen-deuterium mixture revealed presence of one hydrogen atom in the complex. The second nucleus with I = 1/2 is apparently a phosphorus atom. Presence of single iron atom was verified by doping with iron heaving modified isotope content. An intensity of the previously reported TU6 signal, related to iron-phosphorus complex, was significantly suppressed in hydrogen-doped samples.

scholarly journals Integrated ionomic and transcriptomic dissection reveals the core transporter genes responsive to varying cadmium abundances in allotetraploid rapeseed

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ting Zhou ◽  
Cai-peng Yue ◽  
Tian-yu Zhang ◽  
Ying Liu ◽  
Jin-yong Huang ◽  
...  
Keyword(s):  
Metal Ion ◽  
Plant Cell Wall ◽  
Plant Biomass ◽  
Ion Homeostasis ◽  
Molecular Engineering ◽  
Cd Uptake ◽  
Heterogeneous Distribution ◽  
Metal Ion Homeostasis ◽  
The Core ◽  
Essential Nutrient

Abstract Background Oilseed rape (B. napus L.) has great potential for phytoremediation of cadmium (Cd)-polluted soils due to its large plant biomass production and strong metal accumulation. Soil properties and the presence of other soluble compounds or ions, cause a heterogeneous distribution of Cd. Results The aim of our study was to reveal the differential responses of B. napus to different Cd abundances. Herein, we found that high Cd (50 μM) severely inhibited the growth of B. napus, which was not repressed by low Cd (0.50 μM) under hydroponic culture system. ICP-MS assays showed that the Cd2+ concentrations in both shoots and roots under 50 μM Cd were over 10 times higher than those under 0.50 μM Cd. Under low Cd, the concentrations of only shoot Ca2+/Mn2+ and root Mn2+ were obviously changed (both reduced); under high Cd, the concentrations of most cations assayed were significantly altered in both shoots and roots except root Ca2+ and Mg2+. High-throughput transcriptomic profiling revealed a total of 18,021 and 1408 differentially expressed genes under high Cd and low Cd conditions, respectively. The biological categories related to the biosynthesis of plant cell wall components and response to external stimulus were over-accumulated under low Cd, whereas the terms involving photosynthesis, nitrogen transport and response, and cellular metal ion homeostasis were highly enriched under high Cd. Differential expression of the transporters responsible for Cd uptake (NRAMPs), transport (IRTs and ZIPs), sequestration (HMAs, ABCs, and CAXs), and detoxification (MTPs, PCR, MTs, and PCSs), and some other essential nutrient transporters were investigated, and gene co-expression network analysis revealed the core members of these Cd transporters. Some Cd transporter genes, especially NRAMPs and IRTs, showed opposite responsive patterns between high Cd and low Cd conditions. Conclusions Our findings would enrich our understanding of the interaction between essential nutrients and Cd, and might also provide suitable gene resources and important implications for the genetic improvement of plant Cd accumulation and resistance through molecular engineering of these core genes under varying Cd abundances in soils.

Turbulent Transport Measurements in a Heated Boundary Layer: Combined Effects of Free-Stream Turbulence and Removal of Concave Curvature

1997 ◽  
Vol 119 (3) ◽  
pp. 413-419 ◽  
Author(s):  
M. D. Kestoras ◽  
T. W. Simon
Keyword(s):  
Boundary Layer ◽  
Free Stream ◽  
Turbulent Transport ◽  
Outer Part ◽  
Test Facility ◽  
Free Stream Turbulence ◽  
The Core ◽  
Concave Wall ◽  
Prandtl Numbers ◽  
Near Wall

Turbulence measurements for both momentum and heat transport are taken in a boundary layer over a flat recovery wall downstream of a concave wall (R = 0.97 m). The boundary layer appears turbulent from the beginning of the upstream, concave wall and grows over the flat test wall downstream of the curved wall with negligible streamwise acceleration. The strength of curvature at the bend exit, δ99.5/R, is 0.04. The free-stream turbulence intensity (FSTI) is ~8 percent at the beginning of the curve and is nearly uniform at ~4.5 percent throughout the recovery wall. Comparisons are made with data taken in an earlier study, in the same test facility, but with a low FSTI (~0.6 percent). Results show that on the recovery wall, elevated FSTI enhances turbulent transport quantities such as −uν and νt in most of the outer part of the boundary layer, but near-wall values of νt remain unaffected. This is in contrast to near-wall νt values within the curve which decrease when FSTI is increased. At the bend exit, decreases of −uν and νt due to removal of curvature become more profound when FSTI is elevated, compared to low-FSTI behavior. Measurements in the core of the flow indicate that the high levels of cross transport of momentum over the upstream concave wall cease when curvature is removed. Other results show that turbulent Prandtl numbers over the recovery wall are reduced to ~0.9 when FSTI is elevated, consistent with the rise in Stanton numbers over the recovery wall.

scholarly journals Effective ascorbate-free and photolatent click reactions in water using a photoreducible copper(II)-ethylenediamine precatalyst

2015 ◽  
Vol 11 ◽  
pp. 1950-1959 ◽  
Author(s):  
Redouane Beniazza ◽  
Natalia Bayo ◽  
Florian Molton ◽  
Carole Duboc ◽  
Stéphane Massip ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Copper Catalysts ◽  
Water Soluble ◽  
Sodium Ascorbate ◽  
X Ray Diffraction ◽  
Click Reactions ◽  
Ethylenediamine Complex ◽  
Layer Chromatography ◽  
Full Conversion ◽  
Uva Radiation

The search for copper catalysts able to perform effectively click reactions in water in the absence of sodium ascorbate is an active area of current research with strong potential for applications in bioconjugation. The water-soluble and photoreducible copper(II)–EDA (EDA = ethylenediamine) complex 1, which has two 4-benzoylbenzoates acting as both counterion and photosensitizer, has been synthesized and characterized by different techniques including single crystal X-ray diffraction. Highly efficient photoreduction was demonstrated when solutions of 1 in hydrogen atom donating solvents, such as THF or MeOH, were exposed to UVA radiation (350–400 nm) provided by a low pressure mercury lamp (type TLC = thin-layer chromatography, 365 nm), or by a 23 W fluorescent bulb, or by ambient/sunlight. In water, a much poorer hydrogen atom donating solvent, the photoreduction of 1 proved inefficient. Interestingly, EPR studies revealed that complex 1 could nonetheless be effectively photoreduced in water when alkynes were present in solution. The catalytic activity of 1 for click reactions involving a range of water-soluble alkynes and azides, in particular saccharides, was tested under various illumination conditions. Complex 1 was found to exhibit a photolatent character, the photogenerated copper(I) being very reactive. On irradiating aqueous reaction mixtures containing 1 mol % of 1 at 365 nm (TLC lamp) for 1 h, click reactions were shown to proceed to full conversion.

Phycosiphon incertum revisited: Anconichnus horizontalis is its junior subjective synonym

1994 ◽  
Vol 68 (6) ◽  
pp. 1396-1402 ◽  
Author(s):  
Andreas Wetzel ◽  
Richard G. Bromley
Keyword(s):  
Spatial Arrangement ◽  
Trace Fossils ◽  
Trace Fossil ◽  
Homogeneous Material ◽  
Mantle Material ◽  
Single Tube ◽  
The Core ◽  
Host Sediment ◽  
Dark Core ◽  
Subjective Synonym

Comparisons between Phycosiphon incertum Fischer-Ooster (1858) and Anconichnus horizontalis Kern (1978) show that these two monotypic ichnogenera do not differ significantly in geometry, size, sediment fill, and environmental occurrence. Therefore, taxonomic priority has to be given to Phycosiphon and Anconichnus becomes a subjective junior synonym. The trace fossil is a small, highly lobed spreite structure produced by a zoned backfill consisting of a pale mantle and dark core. In a few cases, a meniscate structure is visible in the core. The spreite sediment is an extension of the mantle material; it commonly is poorly visible. The spreite-producing behavior may be locally interrupted, leaving a single tube of backfill. The spatial arrangement of the trace fossils seems to depend on the host sediment; in muddy and homogeneous material the lobes tend to be oriented randomly, including vertically, whereas in laminated sand and silty sediments they tend to lie parallel to bedding. This latter orientation is exaggerated by compaction. Textural differences between host sediment and spreite or mantle may be subtle and not always evident. Observations in modern sediments are in agreement with the type material of both ichnogenera.

scholarly journals HIATUS PADA KALA EOSEN-MIOSEN TENGAH DI TINGGIAN ROO, SAMUDRA HINDIA, BERDASARKAN BIOSTRATIGRAFI NANNOPLANKTON

2016 ◽  
Vol 6 (3) ◽  
Author(s):  
Mimin Karmini ◽  
M. Hendrizan
Keyword(s):  
Late Miocene ◽  
Coal Gasification ◽  
Outer Part ◽  
Emiliania Huxleyi ◽  
Piston Core ◽  
Sea Floor ◽  
The Core ◽  
Authigenic Mineral ◽  
Plastic Industry ◽  
Gephyrocapsa Oceanica

Nanoplankton dari dua puluh satu percontoh dari Tinggian Roo (MD982156) yang diperoleh selama Ekspedisi MD III - IMAGES IV telah dianalisis untuk kepentingan penelitian biostratigrafi study. Percontoh sedimen diambil dengan menggunakan penginti isap yang besar sekali (giant piston core). Lokasi daerah telitian adalah di Tinggian Roo, Samudra Hindia, Selatan Jawa Timur, di luar Parit Jawa. Hasil penelitian menunjukkan bahwa berdasarkan nanoplankton, biostratigrafi daerah telitian dapat dibagi ke dalam 8 Zona yakni zona-zona: Discoaster multiradiatus, D. prepentaradiatus, D. asymmetricus, Pseudoemiliania lacunosa, D. brouweri, D.brouweri-oceanica, Gephyrocapsa oceanica dan Emiliania huxleyi. Umur Paleosen ditunjukkan dengan adanya Discoaster multiradiatus sebagai spesies yang dominan, sedangkan sedimen yang berumur Miosen Akhir adalah D. prepentaradiatus. Sedimen lempung tufaan pada kedalaman 30 m bawah dasar laut ke bagian paling bawah dari penampang yang didominasi oleh mineral Phillipsite, ternyata mengandung nanoplankton yang berumur Paleosen, sedangkan dari kedalaman 30 m ke bagian atas dari penampang sedimen ditutupi secara langsung oleh sedimen yang berumur Miosen Akhir – Holosen. Jadi di lokasi penelitian ini telah terjadi hiatus antara Eosen sampai paling tidak bagian bawah dari Miosen Akhir. Adapun Phillipsit dikenal sebagai mineral yang secara authigenic terjadi di laut dalam yang bisa berasal dari hasil kegiatan gunung api. Manfaat mineral Phillipsit di dalam industri plastik, antara lain dapat dipakai dalam pembuatan resin termoaktif dan sebagai pemacu dalam proses pengerasan. Kelompok Zeolit ini juga digunakan untuk menghilangkan kesadahan dalam industri deterjen, menjernihkan kelapa sawit, menyerap zat warna pada minyak hati ikan hiu, sebagai katalisator pada proses gasifikasi batubara yang berkadar belerang dan/atau nitrogen tinggi yang menghasilkan gas bersih Kata Kunci: Hiatus, Kala Esosen-miosen, Tinggian Roo, Biostratigrafi Nanno Plankton Nannoplankton of twenty one samples from Roo Rise (MD982156 core) obtained during MD III - IMAGES IV Expedition were analysed for biostratigraphic study. The samples were taken by using giant piston core. This core is located in Indian Ocean, south of East Jawa, outer part of Jawa Trench. The results of the study indicate that, based on nannoplankton biostratigraphy of the study area, there are eight zones namely: Discoaster multiradiatus, D. prepentaradiatus, D. asymmetricus, Pseudoemiliania lacunosa, D. brouweri, D.brouweri-oceanica, Gephyrocapsa oceanica dan Emiliania huxleyi. Paleocene sediment is indicated by the presence of Discoaster multiradiatus as the dominant species and Late Miocene sediment is indicated by the presence D. pentaradiatus. The sediments from 30 m down to the base of the core, which is dominated by Phillipsite minerals (Zeolite Group), is composed of nannoplankton of Paleocene age, whereas from 30 m below sea floor (bsf) to the top of the core, the sediment is directly overlain by the sediment of Late Miocene – Holocene ages. Therefore there was a hiatus occurred in the study area between Eocene to at least the lower part of Late Miocene. Phillipsite is known as an authigenic mineral deposited in the deep sea that could be derived from the volcanic activity products. This mineral has a benefit in the plastic industry that can be used in making thermoactive resin and as a catalyst in hardening process. The Zeolite Group is also used in removing hardness in detergen industry, cleaning palm oil, absorbing color in lever oil of shark and as a catalyst in coal gasification having high sulphur and nitrogen producing clean gas. Keyword: Hiatus, Eosen-miosen ages, Roo Rise, Biostratigrafi Nanno Plankton

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