Strip tillage as an implementation of resource-saving approaches in areas of risky agriculture

Zones of farming with arid climate require scientific justification and competent approach in the field of tillage. The main objectives in developing approaches to mechanical tillage in the field of soil-protective technologies are to reduce erosion processes, accumulate and retain moisture, create favorable conditions for the growth of cultivated plants in the root zone. Reducing the number of soil treatments during the growing season of plants contributes to the ecologization of the soil treatment process and the solution of economic problems. Soil-protective measures also include methods of wind speed reduction in the surface layer. In the article various approaches to the methods of mechanical soil tillage, recommended for use in the zones of risky agriculture on the example of the Volgograd region, are considered. Technical solutions, which allow solving the problems of a modern crop producer by improving the environmental friendliness of agriculture, increasing the crop yield, and increasing the profitability of production, are proposed

Engineering Silicon Nanocrystals: Theoretical study of the effect of Codoping with Boron and Phosphorus

We show that the optical and electronic properties of nanocrystalline silicon can be efficiently tuned using impurity doping. In particular, we give evidence, by means of ab-initio calculations, that by properly controlling the doping with either one or two atomic species, a significant modification of both the absorption and the emission of light can be achieved. We have considered impurities, either boron or phosphorous (doping) or both (codoping), located at different substitutional sites of silicon nanocrystals with size ranging from 1.1 nm to 1.8 nm in diameter. We have found that the codoped nanocrystals have the lowest impurity formation energies when the two impurities occupy nearest neighbor sites near the surface. In addition, such systems present band-edge states localized on the impurities giving rise to a red-shift of the absorption thresholds with respect to that of undoped nanocrystals. Our detailed theoretical analysis shows that the creation of an electron-hole pair due to light absorption determines a geometry distortion that in turn results in a Stokes shift between adsorption and emission spectra. In order to give a deeper insight in this effect, in one case we have calculated the absorption and emission spectra going beyond the single-particle approach showing the important role played by many-body effects. The entire set of results we have collected in this work give a strong indication that with the doping it is possible to tune the optical properties of silicon nanocrystals.Comment: 14 pages 19 figure

ПЕРВЫЙ ОПЫТ ИСПОЛЬЗОВАНИЯ «КЕМАНГИОПРОТЕЗА» ПРИ ОПЕРАЦИИ NORWOOD – SANO

HighlightsThe article presents a unique clinical case of correction of hypoplastic left heart syndrome with Norwood procedure using a “KemAngioprosthesis” vascular xenograft as a Sano shunt. AbstractWe present the first successful clinical case of using the “KemAngioprosthesis” vascular xenograft in the pulmonary position as the Sano shunt in the Norwood procedure for correction of hypoplastic left heart syndrome. A newborn baby (gestation period of 38 weeks) diagnosed with congenital heart disease, and hypoplastic left heart syndrome was admitted to the Research Institute for Complex Issues of Cardiovascular Diseases. The child survived the first stage of the modified Norwood procedure (Sano shunt) using a biological vascular prosthesis. This clinical case showed that using the “KemAngioprosthesis” vascular xenograft in Norwood procedure to modify pulmonary blood flow by creating an anastomosis between the right ventricle and bifurcation of the pulmonary artery is effective and safe in the short-term period.Основные положенияВ статье представлен уникальный случай гемодинамической коррекции синдрома гипоплазии левых отделов сердца. При операции Norwood в качестве шунта Sano использован сосудистый ксенографт «КемАнгиопротез» (ЗАО «НеоКор», Кемерово). АбстрактПредставлен первый успешный опыт применения артериального аутографта «КемАнгиопротез» в легочной позиции при операции Norwood – Sano, направленной на гемодинамическую коррекцию синдрома гипоплазии левого желудочка. В НИИ КПССЗ поступил новорожденный со сроком гестации 38 нед. с диагнозом: врожденный порок сердца, синдром гипоплазии левых отделов сердца. Ребенку успешно выполнен первый этап гемодинамической коррекции методом Norwood – Sano с использованием биологического сосудистого протеза. Данный клинический случай показал, что применение «КемАнгиопротеза» при операции Norwood – Sano для модификации легочного кровотока путем создания анастомоза между правым желудочком и бифуркацией легочной артерии является эффективным и безопасным в госпитальном периоде

Robot for strip spraying of vegetable crops

The article deals with the problem of reducing the use of agrochemicals through the use of strip spraying using robotic tools that increase the uniformity and accuracy of the distribution of pesticides. The proposed design of the strip spraying module is based on the principle of consistent development of unified modular components in order to change the basic characteristics of the robotic complex. The use of a robotic complex for strip spraying of vegetable crops during treatment with pesticides or liquid mineral fertilizers will ensure an improvement in the quality of plant processing, a reduction in the hectare consumption of the working solution and a negative impact on the environment

New technical solution for resource-saving tasks in chemical plant protection

The problems in the production of row crops are considered. The technical solution in the field of chemical protection of plants, aimed at obtaining high quality products while reducing the cost of production, is offered. The retrofitting of serial boom sprayers with special divider bodies makes it possible to retain the function of continuous spraying with the possibility of chemical treatment in strips at the desired phase of growth and development of cultivated plants. It also describes the possibility of solving environmental problems in the agricultural industry by reducing the chemical load on the soil

Toward a New Generation of Compact Transportable Yb⁺ Optical Clocks

Optical atomic clocks are currently one of the most sensitive tools making it possible to precisely test the fundamental symmetry properties of spacetime and Einstein’s theory of relativity. At the same time, the extremely high stability and accuracy of compact transportable optical clocks open new perspectives in important fields, such as satellite navigation, relativistic geodesy, and the global time and frequency network. Our project aimed to develop a compact transportable optical clock based on a single ytterbium ion. We present the first prototype of the Yb+ clock (298 kg in 1 m3) and present several solutions aimed to improve the clock’s robustness to approach the demands of a space-qualified system. We present spectroscopic studies of a 435.5 nm quadrupole clock transition with Fourier-limited spectra of 25 Hz. The estimated instability of the output frequency at 1 GHz, which was down-converted with an optical frequency comb (OFC), is at the level of 9×10−15/τ, and the long-term instability and inaccuracy are at the level of 5×10−16. As the next steps, we present a new design for the clock laser and the OFC

Toward a New Generation of Compact Transportable Yb+ Optical Clocks

Optical atomic clocks are currently one of the most sensitive tools making it possible to precisely test the fundamental symmetry properties of spacetime and Einstein’s theory of relativity. At the same time, the extremely high stability and accuracy of compact transportable optical clocks open new perspectives in important fields, such as satellite navigation, relativistic geodesy, and the global time and frequency network. Our project aimed to develop a compact transportable optical clock based on a single ytterbium ion. We present the first prototype of the Yb+ clock (298 kg in 1 m3) and present several solutions aimed to improve the clock’s robustness to approach the demands of a space-qualified system. We present spectroscopic studies of a 435.5 nm quadrupole clock transition with Fourier-limited spectra of 25 Hz. The estimated instability of the output frequency at 1 GHz, which was down-converted with an optical frequency comb (OFC), is at the level of 9×10−15/τ, and the long-term instability and inaccuracy are at the level of 5×10−16. As the next steps, we present a new design for the clock laser and the OFC