X-ray crystallography is commonly used to determine crystal structures, whether continuous or ultrashort x rays are used. In this paper, it is shown that using only ultrashort pulses, it is possible to determine interplanar spacing in diamond layers, the distance between which can be only a few angstroms. The results obtained can be extended, with further development of the presented theory, to determine 3D objects in the crystal structure, the dimensions of which can be only a few angstroms.
Currently, the use of ultrashort pulses is one of the main methods for studying the structure and dynamics of ultrafast processes in atomic and molecular systems. In this paper, it is shown that ultrashort pulses can be used to determine the time dynamics of crystal plates with ultrahigh temporal and spatial resolution, the distance between which can be only a few angstroms. As an example, the dynamics of diamond layers with NV-centers is considered. The results obtained have prospects for developing the presented theory for more complex structural objects and dynamic processes in matter.
The concentration of negatively charged vacancies resulting from electron irradiation of a synthetic single-crystal diamond plate with nitrogen-substituted vacancies was calculated. The concentration was calculated using IR spectroscopy and analyzed using PAS positron annihilation spectroscopy. It is shown that PAS and the use of a monochromatic positron beam can be used for non-destructive monitoring of the vacancy concentration along the depth of a diamond plate.
The X-ray diffraction analysis is one of the main methods to determine the structure of crystalline materials using both cw X rays and ultrashort pulses. Ultrashort pulses are usually utilized to observe dynamic processes in atomic and molecular systems. In this work, it has been shown that ultrashort pulses can have another important application in the determination of the interplanar distance between diamond layers with NV centers, which can be separated by only several angstroms. The obtained results can be extended to more complex structures and can be finally developed to a new three-dimensional tomography method with angstrom resolution.
It is well known that the basis of diffraction analysis of matter is scattering, including the scattering of ultrashort laser pulses. In the theory of scattering of ultrashort pulses, the pulse duration parameter is usually not taken into account, which leads to some error. This error may be more significant than the considered effects in the scattering of the pulse on the studied structure. In this paper, it is shown that the pulse duration parameter should be taken into account when scattering X-ray pulses on oriented diamonds with NV centers. It is shown that the scattering spectra can be used to judge the orientation of NV centers in the diamond structure. The obtained results may be very different from the widely used theory of diffraction analysis, which confirms the necessity of taking into account the pulse duration parameter in the diagnosis of complex structures.
Currently, synthetic diamonds are finding new applications. Quantum devices can be created based on diamond plates with the desired concentration of defects in the structure of the crystal lattice. NV color centers can be used in quantum applications by irradiating plates with high-energy particles, followed by annealing at temperatures above 800°C to develop the spin-optical properties of the centers Diamond plates are subjected to electron irradiation and much less often to proton irradiation. As a result, synthetic diamond plates with NV centers ob-tained by proton irradiation are less studied, although proton irradiation makes it possible to obtain a layered structure of NV centers. In this work, single crystal diamond plates irradiated with protons were studied using polarization microscopy, IR spectroscopy and ODMR spectros-copy. It is shown that when creating NV centers, the distribution and concentration of C – defects in the sample, as well as mechanical stresses before and after irradiation (with subsequent an-nealing), can differ significantly from each other.
This article presents the results of an investigation into defects in synthetic monocrystalline diamond plates after electron irradiation. Data on defect concentration distribution in the infrared (IR) range are given. In addition to IR spectroscopy, positron annihilation spectroscopy (PAS) is used to study the vacancy defects in diamonds. It is shown that PAS using a monochromatic positron beam can be used for the nondestructive control of vacancy distribution along the depth of the diamond plate.
A method is proposed for increasing the resistance of a superhydrophobic coating based on a CNT xerogel to frost deposition through the use of decorating nanoparticles. The effects of the addition of fullerenes, carbon nanoonions (CNOs), detonation nanodiamonds, silicon dioxide, and paraffin to the xerogel are tested. An increase in the resistance of the coating to the deposition of condensate in the form of frost is revealed. The addition of fullerene C 60 leads to the best results. Increasing the resistance to icing allows us to spend less power on heating the surface during short cold snaps, bypassing the anti-icing properties of the protective superhydrophobic layer. However, the application of this approach shows a deterioration in the resistance of the coating to the penetration of the spray. This is given a qualitative explanation and measures to combat it are proposed. No effect of the additives on the mechanical properties of the coating or its resistance to damage is detected. In additon, decorating additives affect the formation of the coating relief. With this, it is possible to influence the stochastic processes of the formation of roughness during the drying of the xerogel.
Currently, diamonds are widely used in science and technology. However, the properties of diamonds due to their defects are not fully understood. In addition to optical methods, positron annihilation spectroscopy (PAS) can be successfully used to study defects in diamonds. Positrons are capable of detecting vacancies, and small and large clusters of vacancies induced by irradiation, by providing information about their size, concentration, and chemical environment. By mapping in the infrared (IR) range, it is possible to consider the admixture composition of the main inclusions of the whole plate. This article presents the results of a study of defects in synthetic diamond plates, one of which was irradiated by electrons. It presents data about the distribution of the defect concentration obtained by Infrared spectroscopy. PAS with a monochromatic positron beam can be used as a non-destructive technique of detecting defects (vacancy) distribution over the depth of diamond plates.
Magnetic resonance methods for express analysis and control of diamond wafers with NV − centers for quantum technologies were developed. The scanning NV − -based ODMR spectrometer was built to analyze NV − local concentration, coherent properties, stress/strain, nitrogen content, electron-nuclear interactions in diamond wafers for quantum technologies. As an example, a 3D image of the ODMR and PL maps was presented for a non-uniform distribution of NV − centers in a diamond wafer, which had several growth zones with significantly different concentrations of nitrogen. The local stress/strain map was obtained by measuring the splitting of the ODMR line in zero magnetic field at room temperature. The double ODMR line is a consequence of the stress-induced splitting of the doublet with projections M S = + 1 and M S = − 1 in the ground triplet state of the NV − center. Local concentration of nitrogen donors (in EPR literature it is designated as N or P1 centers) was estimated from the ratio of the intensity of satellites caused by interaction with nitrogen donors and the central line of ODMR. The central line has a 2E split into two overlapping lines, the intensity of one of the lines is selected. The spectrometer is also designed to perform pulsed measurements of Rabi oscillations, spin–lattice and spin–spin relaxation times at wafer points isolated by focused laser excitation. A new option for using a spectrometer was introduced for measuring the ODMR of NV − centers in a linearly polarized light, which allowed to distinguish PL for centers of a certain orientation and suppress the PL from others.
The previous article introduced the idea of a superhydrophobic coating from carbon nanoparticles that can combine the lotus effect, the slip effect and electric current heating. A further development of this idea was suggested. The article demonstrated the possibility of a practical implementation of the suggested approach using two coating layers—the electro-thermal layer from carbon nanotubes and the water-repellent layer from onion-like carbons. This coating allows to conserve energy during periods of slight cooling simply due to the use of the lotus effect. The heating is used to prevent icing at lower temperatures. The best contact angle achieved equals 155.9 ± 0.5 degrees at a slip start angle of 1.2 ± 0.5 degrees.
The scattering of ultra-short X-ray pulses (USPs) is an important component of diffraction analysis of matter. Usually, the specific scattering of such USPs is not taken into account to determine the structure of a substance. Taking into account the specifics of scattering on complex structures will give more accurate results when deciphering complex structures. In this work, it is shown that when X-ray USPs are scattered on diamond with NV centers, it is necessary to take into account the pulse duration. The results obtained can be very different from the widely used theory of diffraction analysis, which confirms the need to take into account the specifics of USP scattering when diagnosing complex structures. It is shown that the scattering spectra are very sensitive to the concentration of NV-centres in the diamond structure, and this can be used in diffraction analysis.
Usually, loading and unloading of cargo ships takes place in ports that are equipped with the infrastructure necessary to carry out such operations. In the Arctic, often a helicopter is the only way to get the cargo to the right place. Finding the optimal geographic location for unloading a ship using helicopters is an important task. It is necessary to create a support system for making the right decisions in such situations. Mathematical modeling has been used to find the geographical location that ensures the most favorable and quickest delivery of cargo from a vessel to its destination, using a helicopter. A criterion has also been found in which the search for the optimum point is a more rational way of unloading the vessel compared to other discharge options. The maps of the economic benefits of loading and unloading operations in this model have been developed. Using the example of the developed model, it is shown that during the transportation of goods in Ob Bay, significant economic and temporary advantages can be obtained. The developed model can be extended to the case of cargo delivery not only in the Arctic conditions, but also where the transport infrastructure is insufficiently developed.
It is well known that the scattering of ultrashort pulses (USPs) of an electromagnetic field in the X-ray frequency range can be used in diffraction analysis. When such USPs are scattered by various polyatomic objects, a diffraction pattern appears from which the structure of the object can be determined. Today, there is a technical possibility of creating powerful USP sources and the analysis of the scattering spectra of such pulses is a high-precision instrument for studying the structure of matter. As a rule, such scattering occurs at a frequency close to the carrier frequency of the incident USP. In this work, it is shown that for high-power USPs, where the magnetic component of USPs cannot be neglected, scattering at the second harmonic appears. The scattering of USPs by the second harmonic has a characteristic diffraction pattern which can be used to judge the structure of the scattering object; combining the scattering spectra at the first and second harmonics therefore greatly enhances the diffraction analysis of matter. Scattering spectra at the first and second harmonics are shown for various polyatomic objects: examples considered are 2D and 3D materials such as graphene, carbon nanotubes, and hybrid structures consisting of nanotubes. The theory developed in this work can be applied to various multivolume objects and is quite simple for X-ray structural analysis, because it is based on analytical expressions.