Search

Field experiments and laboratory studies were carried out during 2018-2021 on the basis of the experimental field and the research laboratory of the Smolensk State Agricultural Academy. The following varieties of winter wheat were the object of research: Measure, Nemchinovskaya 85, Skipetr (domestic selection) STRG - 872317 (foreign selection); varieties of winter triticale: Consul, Nina (domestic selection), Nord-1173303 MS, Mikhas (foreign selection). In our studies, the studied varieties of winter wheat and winter triticale of domestic and foreign breeding were ecologically plastic and formed a yield of 5.5-6.5 t/ha. We found that the winter wheat variety Nemchinovskaya 85 at a yield level of 5.77 t/ha exceeded the varieties Mera by 0.13 t/ha, Skipetr by 0.77 t/ha STRG - 88237 by 0.17 t/ha. According to the yield level of winter triticale, the domestic variety Konsul stood out - 5.86 t/ha and the variety of foreign selection Nord 1173303 MS - 5.28 t/ha. The duration of the growing season for varieties of winter crops, depending on the conditions of years, was 282-339 days and corresponded to the morphobiological characteristics of these varieties. In terms of precocity, winter wheat varieties were inferior to winter triticale varieties up to 5 or more days. When overwintering plants (68-77%) varieties of domestic breeding for winter wheat Nemchinovskaya 85 and Mera; for winter triticale, Consul and Nina were more winter-hardy (by 3-8%) than varieties of foreign selection. The article presents qualitative indicators of grain evaluation, where winter wheat varieties Nemchinovskaya 85 and Mera were distinguished by their physicochemical properties; in varieties of winter triticale - Consul. So the weight of 1000 grains in these varieties was respectively: 48.2; 47.9, and 45.5 g; vitreousness: 73;72;58%, nature: 799;765;750 g/l; falling number: 313;303;261 s. The protein content in the grain of winter wheat varieties ranged from 13.0 to 13.8% and in winter triticale varieties - from 12.3 to 13.1%. The studied varieties of domestic and foreign breeding retained their genotypicity in terms of morphobiological characteristics, physicochemical, biochemical and technological properties. Thus, in terms of gluten content and its quality, both in grain and in flour, winter wheat varieties corresponded to the indicators - 3 classes, winter wheat varieties triticale - 4 classes. We found that the rheological and baking properties of flour in winter wheat varieties were significantly higher than in winter triticale varieties. The best indicators of these properties in terms of flour strength were in winter wheat varieties Nemchinovskaya 85-279 J and Mera - 269 J and in the winter triticale variety Consul - 156 J. The bakery assessment of the loaves showed that the Nemchinovskaya 85 variety stood out in terms of bread volume, surface, crust color, crumb structure, aroma with a volume of 993 mm3 and a bread score of 4.8 points. In a comprehensive assessment of bread from winter triticale grain, the best indicators were in the Consul variety and amounted to 655 mm3 and 3.6 points, respectively. At the same time, when using grain varieties of winter triticale in baking production, it is necessary to use wheat flour as an improver, from 30 to 50%.

The detailed studies of the surface structure of synthetic boron-doped diamond single crystals using both conventional X-ray and synchrotron nano- and microbeam diffraction, as well as atomic force microscopy and micro-Raman spectroscopy, were carried out to clarify the recently discovered features in them. The arbitrary shaped islands towering above the (111) diamond surface are formed at the final stage of the crystal growth. Their lateral dimensions are from several to tens of microns and their height is from 0.5 to 3 μm. The highly nonequilibrium conditions of crystal growth enhance the boron solubility and, therefore, lead to an increase of the boron concentrations in the islands on the surface up to 1022 cm−3, eventually generating significant stresses in them. The stress in the islands is found to be the volumetric tensile stress. This conclusion is based on the stepwise shift of the diamond Raman peak toward lower frequencies from 1328 to 1300 cm−1 in various islands and on the observation of the shift of three low-intensity reflections at 2-theta Bragg angles of 41.468°, 41.940° and 42.413° in the X-ray diffractogram to the left relative to the (111) diamond reflection at 2theta = 43.93°. We believe that the origin of the stepwise tensile stress is a discrete change in the distances between boron–carbon layers with the step of 6.18 Å. This supposition explains also the stepwise (step of 5 cm−1) behavior of the diamond Raman peak shift. Two approaches based on the combined application of Raman scattering and X-ray diffraction data allowed determination of the values of stresses both in lateral and normal directions. The maximum tensile stress in the direction normal to the surface reaches 63.6 GPa, close to the fracture limit of diamond, equal to 90 GPa along the [111] crystallographic direction. The presented experimental results unambiguously confirm our previously proposed structural model of the boron-doped diamond containing two-dimensional boron–carbon nanosheets and bilayers.

Additional file 1. Supplementary information for Structure investigations of Islands with Atomic-Scale Boron–Carbon Bilayers in Heavily Boron-Doped Diamond Single Crystal: Origin of Stepwise Tensile Stress.

Here we demonstrate performance of an original lab system designed for testing of X-ray parabolic compound refractive lenses (CRL) manufactured from a high-quality single-crystalline synthetic diamond grown by the high-pressure hightemperature technique. The basic parameters of a diamond CRL comprised from 28 plano-concave lenses such as the focal length of 634 mm, transmissivity of 0.36, field of view of ~1 mm and resolution of 6 µm have been determined. Usually such measurements are performed on synchrotron radiation facilities. In this work characterization of CRL was performed by means of instruments and components that are available for laboratories such as the Rigaku 9kW rotating anode X-ray generator, the PANalytical parallel beam X-ray mirror, a 6 m long optical bench, high precision multi-axis goniometers, high resolution X-ray emulsion films, and ultra-fast high-sensitive X-ray area detector PIXel3D. Developed setup was used to find differences between experimental and design parameters, which is very important for the improvement of CRLs manufacturing technology.

2D parabolic X-ray compound refractive lens was manufactured by laser micro-machining of a single-crystal diamond. The lens consists of parabolic half lenses with apertures of 1 mm and parabola apex radii of 200 μm. It has been tested at the synchrotron undulator source (ID06, ESRF) and at a laboratory setup using MetalJet X-ray tube with a liquid-gallium jet as the anode. X-ray imaging and focusing modes were used. Unique optical and thermal properties of singlecrystalline diamond lenses allow them to be applied as focusing, imaging and beam-conditioning elements at high-heat flux beams of today and future X-ray sources.

The insufficient data on a structure of the boron-doped diamond (BDD) has frustrated efforts to fully understand the fascinating electronic properties of this material and how they evolve with doping. We have employed X-ray diffraction and Raman scattering for detailed study of the large-sized BDD single crystals. We demonstrate a formation of boron-carbon (B-C) nanosheets and bilayers in BDD with increasing boron concentration. An incorporation of two boron atoms in the diamond unit cell plays a key role for the B-C nanosheets and bilayer formation. Evidence for these B-C bilayers which are parallel to {111} planes is provided by the observation of high-order, super-lattice reflections in X-ray diffraction and Laue patterns. B-C nanosheets and bilayers minimize the strain energy and affect the electronic structure of BDD. A new shallow acceptor level associated with B-C nanosheets at ~37 meV and the spin-orbit splitting of the valence band of ~6 meV are observed in electronic Raman scattering. We identified that the superconducting transitions occur in the (111) BDD surfaces only. We believe that the origin of Mott and superconducting transitions is associated with the two-dimensional (2D) misfit layer structure of BDD. A model for the BDD crystal structure, based on X-ray and Raman data, is proposed and confirmed by density functional theoretical calculation. Electronic supplementary material The online version of this article (doi:10.1186/s11671-015-1215-6) contains supplementary material, which is available to authorized users.

Laser micro-machining of single-crystal diamond was successfully applied to the manufacturing of a 2D parabolic X-ray compound refractive lens which consists of 24 plano-concave lenses with the parabola apex radius of 200 µm and the aperture of 1 mm. It was tested in the image transfer mode of the tungsten resolution test target at the original home-lab setup using Cukα radiation from a Rigaku rotating anode X-ray generator. The high quality transfer X-ray imaging of this target with resolution < 20 µm in the field of view of 0.6 mm was demonstrated with use of the parabolic diamond compound refractive lens.

We use electronic Raman scattering for studying the band structure of the n s boron acceptor states in diamond. For the first time, the spin–orbit splitting of these acceptor states and the 1 s → n s Lyman series of transitions are observed. The spin–orbit splitting linearly increases with n number. Lyman series exhibit fine structure consisting of four bands each. The energy spacing between series is equal to ∼ 13 meV . Evolution of Raman spectra of the boron-doped diamond with increasing boron concentration is shown. Mott transition is revealed in Raman spectrum. Correct values of Luttinger parameters for diamond are specified.

For the first time investigations of the boron distribution in the subsurface region of HPHT boron-doped diamond that is promising for applications in electronics were carried out by X-ray photoelectron (XPS) and Raman spectroscopy. It was found from XPS data that the boron content decreased gradually more than one order of magnitude in depth of surface. The first-principle calculations have shown that the Raman polarizability in the crossed polarization configuration should increase considerably with boron doping. The Raman spectra from as-grown and polished surfaces of heavily boron-doped diamond are discussed in the context of theoretical results.

Single crystal diamonds 0.2-0.7 cm large doped with boron concentration 10 19 -10 20 cm -3 were grown by temperature gradient method on the seed under pressure P = 5.5 GPa, temperature T= 1650 K. Temperature dependence of electrical resistance had been measured in the range of 0.5-297 K. Boltzmann activation type of conductivity and Mott's VRH law observed in samples in the temperature ranges -200-297 K and -70-297 K respectively. The temperature rise of conductivity in the range of -0.5-50 K for most heavily doped crystals was proportional to T 1/2 . This rule indicates the vicinity of the electronic system to metal-insulator transition.

We have performed a complex analysis of top-quality synthetic diamond HPHT type IIa single crystals in view of their potential application as X-ray optics elements, namely as free electron laser mirrors. We have employed X-ray topography and high-resolution diffractometry along with optical spectroscopy techniques for characterization of our synthetic diamonds.

We have grown and investigated bulk single-crystal heavily boron-doped diamonds possessing superconductivity with . Only the surface layer with the thickness less than showed the degenerate semiconductor behavior with transition to the superconducting state, while the bulk of the crystal was a typical doped semiconductor. The morphology of the surface layer is dendritic polycrystalline with an average boron content of 2.5–2.9 at.%. The typical Josephson junction current-voltage characteristic was observed. The degenerate semiconductor-superconductor transition as in single-crystal high-temperature superconductors and the structural data analysis of the surface layer indicate the two-dimensional character of superconductivity, and the actual superconducting structure is a set of few-nanometer thick boron carbide layers embedded in a diamond structure.

Single crystal graphite specimens were compressed at a room temperature in the diamond anvil cell in the c-axis direction. High pressure values up to 58 GPa and shear deformation up to 30° were used.

Boron doped diamond (BDD) single crystals have been grown under conditions of high isostatic pressure by the temperature gradient method. Numerous equilateral triangles were found on the fluorescence images of {111}-diamond facets. Structural peculiarities of BDD were investigated by JEM-2010 transmission electron microscope with GIF Quantum attachment for electron energy loss spectroscopy (EELS). High resolution image of diamond lattice revealed some distorted {111}-layers. EELS testifies the presence of boron in distorted regions of diamond lattice. The crystallographic features of BDD and their connection with the superconductivity are discussed.