The multiple quantum NMR dynamics in systems of equivalent spins with the dipolar ordered initial state

The multiple quantum (MQ) NMR dynamics in the system of equivalent spins with the dipolar ordered initial state is considered. The high symmetry of the MQ Hamiltonian is used in order to develop the analytical and numerical methods for an investigation of the MQ NMR dynamics in the systems consisting of hundreds of spins from "the first principles". We obtain the dependence of the intensities of the MQ NMR coherences on their orders (profiles of the MQ NMR coherences) for the systems of $200 - 600$ spins. It is shown that these profiles may be well approximated by the exponential distribution functions. We also compare the MQ NMR dynamics in the systems of equivalent spins having two different initial states, namely the dipolar ordered state and the thermal equilibrium state in the strong external magnetic field.Comment: 11 pages 4 figure

QUALITY OF CHICORY ROOT SEEDS DEPENDING ON ITS COATING

The results of the impact of the pelleting coating on the quality of seed of Chicory root have been shown. Pelleting of Chicory root contributed to the increase in its size by the diameter and thickness. The best is to create a pellet coating with weighing of 100% of the weight of the seed, which provides the obtaining of the pelleting seed with the adjustment of 87,2% of fraction with 1,5–2,5 mm in diameter. But, even with the application of 100% of the pelleting mixture on Chicory root seed with similarity to pelleting of 95% on average in the three varieties its germinating energy (by 7%,) and similarity (by 5%) significantly decreased compared with the control. Increasing of the weight of the pelleting coating with weight of 150–200%, these indicators significantly decreased compared with the control and with the pelleting seed where the pellet weight was 100% by weight of the see

INFLUENCE OF HERBICIDES QUALITY ROYAL ROOTS AND SUGAR BEET SEEDS PROCESSING OF CROPS QUEEN

Research on the effect of herbicides against dicotyledonous weeds Betanal Extra and against grass weeds Centurion on uterine beet growth and development is widely used on sugar beet.No significant difference according to the rules and types of herbicides as ChS component and pollinators and polyspermous for fractional composition of roots was found. The basic amount of ChS component of uterine plants was 150 g from 66 to 72%, polyspermous pollinators - from 46 to 72%, which can be planted by existing planting machines. In the meantime, as on the control such roots by the components were 66 and 42% respectively. However, negative influence of these herbicides on seed biometric indicators, which uterine plants were treated with, wasn’t set. Significant violations of ploidy of uterine beet plant components were determined. Uterine sugar beet treatment with maximum dose of herbicides is recommended for sugar beet sowings, the number of diploids is decreased by 51.3–54.2%, while the number of miksploids is increased in 3,9–4,1 times in comparison with the control. The least chromosomal device change is undergone by the uterine plants processing of Betanal Expert herbicide in norm 1 l/ha. Seed analysis showed that even with such significant violations of ploidy of uterine sugar beet plant components, there is no significant influence of herbicides on seed quality, especially for its purity. Using Extra Betanal herbicide as completely norm and as half of the norm, from the recommended rate and Centurion herbicide half norm from the recommended has not led to germination and purity of seed decreasing. Germination of seed was 66–72% (66% in control), purity - 96,1–97,6% in control 96.6% (LSD05 = 2.6%)

Determination of svitchgras sprouting energy and seed germination

Svitchgras (Panicumv virgatum L.) is a new crop for Ukraine. But its cultivation on degraded lands is important in order the solid fuels to produce. Reproduction of this crop by seed is most favorable way. Svitchgras seed is characterized by a high state of calm and especially immediately after harvesting. Current methods for the quality of seed determining cannot be used to assess the intensity of Svitchgras germination, which is inherent in long dormancy. The article highlights the ways to determine the intensity of sprouting and period of accounting of Svitchgras sprouting energy and seed germination. Seed pre-cooling and its term are significantly influenced on the intensity of seed germination. During the four days cooling is provided intensity of germination increasing on the seventh day after sowing by the sprouting at a constant temperature of 20 °C on 15% compared with the control. During four days seed germination at variable temperature after pre-cooling on the 10th and subsequent dates of accounting the intensity of germination was significantly higher than the germination at a constant temperature, due to the influence of low temperature on resting state of seed. With the use of two methods the accounting date of sprouted seed that characterize its sprouting energy is determined. The basis is M.K. Fisova methodology of sprouting energy accounting period in which the vigor is determined by minimum number of days during of which the maximum number of culture seed is germinating. The 10th day after sowing is the term of Svitchgras seed energy of germination definition

Transition from inhomogeneous to homogeneous broadening at a lasing prethreshold

The emission linewidth in active medium emerges due to homogeneous and inhomogeneous broadening. We demonstrate that in lasers with inhomogeneous broadening there is a critical pump rate, above which the special mode forms. This mode consists of locked-in oscillations of cavity mode and of the active particles with different transition frequencies. Below the critical value of the pump rate, the radiation spectrum of the laser has a Gaussian profile, provided that inhomogeneous broadening is dominant. Above the critical value of pump rate, the special mode mostly determines the laser radiation spectrum. As the result, the spectrum attains Lorentz shape characteristic for homogeneous broadening. We demonstrate that the formation of the special mode precedes lasing and that the critical pump rate plays the role of lasing prethreshold. We obtain expressions for the threshold and generation frequency of single-mode laser where both homogeneous and inhomogeneous broadening are present

Multiple quantum NMR dynamics of spin-1/2 carrying molecules of a gas in nanopores

We consider the multiple quantum (MQ) NMR dynamics of a gas of spin carrying molecules in nanocavities. MQ NMR dynamics is determined by the residual dipole-dipole interactions which are not averaged completely due to the molecular diffusion in nanopores. Since the averaged non-secular Hamiltonian describing MQ NMR dynamics depends on only one coupling constant, this Hamiltonian commutes with the square of the total spin angular momentum $\hat I^2$. We use the basis of common eigenstates of $\hat I^2$ and the projection of $I$ on the external magnetic field for investigation of MQ NMR dynamics. This approach allows us to study MQ NMR dynamics in systems consisting of several hundreds of spins. The analytical approximation of the stationary profile of MQ coherences is obtained. The analytical expressions for MQ NMR coherence intensities of the five-spin system in a nanopore are found. Numerical investigations allow us to find the dependencies of intensities of MQ coherences on their orders (the profiles of MQ coherences) in systems consisting of 600 spins and even more. It is shown that the stationary MQ coherence profile in the considered system is an exponential one.Comment: 8 pages, 5 figure

Influence of correlations in active medium on pump-induced exceptional points and strong coupling

Exceptional points show great prospects for applications such as imaging, sensing and designing lasers. Recently, systems with amplifying active medium exhibiting pump-induced exceptional points have attracted much attention due to possibility of controlling strong coupling between light and matter with the aid of pumping. In such structures, the interaction of active molecules with external degrees of freedom, such as phonons or impurities, leads to the destruction of the correlation between polarizations of different molecules. We study the effect of the correlations decay on a system behavior near pump-induced exceptional point. We show that strong coupling persists and eigenvectors together with eigenfrequencies coalesce at a negative value of population inversion, regardless of correlation decay magnitude. Thus, we show that exceptional points are robust to correlation decay, which is crucial for designing systems with exceptional points