The feasibility of using combined soils in greenhouse conditions for growing Osteospermum

Periodically recurring droughts, unstable atmospheric moisture, and elevated air temperatures in summer are characteristic of the Orenburg region, which is part of the South Ural region. Of great scientific and practical importance at the present stage is the creation of soils that are optimal in terms of physical and chemical composition, giving high production results. The article presents the results of experimental data on the use of combined soils in greenhouse conditions in the Orenburg region when growing ornamental plants Osteospermum, for the purpose of decorative landscaping in urban areas, as one of the promising flower crops. In laboratory conditions, when constructing the soil, its chemical composition was carried out before sowing ornamental crops and after transplanting plants into open ground, in order to analyze the needs of plants for the mineral component of the soil and the possibilities of its reuse (secondary) for enriching the open soil of flower beds in urban conditions

CMOS-Analogous Wafer-Scale Nanotube-on-Insulator Approach for Submicrometer Devices and Integrated Circuits Using Aligned Nanotubes

Massive aligned carbon nanotubes hold great potential but also face significant integration/assembly challenges for future beyond-silicon nanoelectronics. We report a wafer-scale processing of aligned nanotube devices and integrated circuits, including progress on essential technological components such as wafer-scale synthesis of aligned nanotubes, wafer-scale transfer of nanotubes to silicon wafers, metallic nanotube removal and chemical doping, and defect-tolerant integrated nanotube circuits. We have achieved synthesis of massive aligned nanotubes on complete 4 in. quartz and sapphire substrates, which were then transferred to 4 in. Si/SiO2 wafers. CMOS analogous fabrication was performed to yield transistors and circuits with features down to 0.5 μm, with high current density 20 μA/μm and good on/off ratios. In addition, chemical doping has been used to build fully integrated complementary inverter with a gain ~5, and a defect-tolerant design has been employed for NAND and NOR gates. This full-wafer approach could serve as a critical foundation for future integrated nanotube circuits

Raman Characterization and Polarity Tuning of Aligned Single-Walled Carbon Nanotubes on Quartz

Raman characterization has been employed to study key features of highly aligned single-walled carbon nanotubes grown on quartz substrates. The nanotubes are observed to possess an estimated metallic/semiconducting ratio of 1:2.7, and Raman spectra also confirm the high integrity of nanotubes before and after being transferred from quartz to Si/SiO2 substrates. Based on the as-grown and the transferred aligned nanotubes, we have further fabricated top- and back-gated nanotube devices, respectively. The top-gated transistors exhibit ambipolar transport characteristics with high transconductance, small subthreshold swing of 110 mV/decade and on/off ratio of 107, while the back-gated transistors show unipolar p-type characteristics. Furthermore, we have demonstrated polarity tuning to produce both predominately n- and p-type top-gated carbon nanotube transistors by controlling the polarity of gate voltage during electrical breakdown, which has great potential for building complementary carbon nanotube circuits.Chemistry and Chemical Biolog

Comparison of Graphene Growth on Single-Crystalline and Polycrystalline Ni by Chemical Vapor Deposition

We report a comparative study and Raman characterization of the formation of graphene on single crystal Ni (111) and polycrystalline Ni substrates using chemical vapor deposition (CVD). Preferential formation of monolayer/bilayer graphene on the single crystal surface is attributed to its atomically smooth surface and the absence of grain boundaries. In contrast, CVD graphene formed on polycrystalline Ni leads to a higher percentage of multilayer graphene (≥3 layers), which is attributed to the presence of grain boundaries in Ni that can serve as nucleation sites for multilayer growth. Micro-Raman surface mapping reveals that the area percentages of monolayer/bilayer graphene are 91.4% for the Ni (111) substrate and 72.8% for the polycrystalline Ni substrate under comparable CVD conditions. The use of single crystal substrates for graphene growth may open ways for uniform high-quality graphene over large areas

Self-Aligned T-Gate High-Purity Semiconducting Carbon Nanotube RF Transistors Operated in Quasi-Ballistic Transport and Quantum Capacitance Regime

Carbon nanotube RF transistors are predicted to offer good performance and high linearity when operated in the ballistic transport and quantum capacitance regime; however, realization of such transistors has been very challenging. In this paper, we introduce a self-aligned fabrication method for carbon nanotube RF transistors, which incorporate a T-shaped (mushroom-shaped) aluminum gate, with oxidized aluminum as the gate dielectric. In this way, the channel length can be scaled down to 140 nm, which enables quasi-ballistic transport, and the gate dielectric is reduced to 2–3 nm aluminum oxide, leading to quasi-quantum capacitance operation. A current-gain cutoff frequency (<i>f</i>_t) up to 23 GHz and a maximum oscillation frequency (<i>f</i>_max) of 10 GHz are demonstrated. Furthermore, the linearity properties of nanotube transistors are characterized by using the 1 dB compression point measurement with positive power gain for the first time, to our knowledge. Our work reveals the importance and potential of separated semiconducting nanotubes for various RF applications

Atmospheric Air Pollution by Stationary Sources in Ulan-Ude (Buryatia, Russia) and Its Impact on Public Health

For the first time in the territory of the Russian Far East, a study related to the establishment of correlations between air quality and public health in Ulan-Ude (Buryatia, Russia) was carried out. This study is based on the analysis of official medical statistics on morbidity over several years, the data on the composition and volume of emissions of harmful substances into the air from various stationary sources, and laboratory measurements of air pollutants in different locations in Ulan-Ude. This study confirmed that the morbidity of the population in Ulan-Ude has been increasing every year and it is largely influenced by air pollutants, the main of which are benzo(a)pyrene, suspended solids, PM2.5, PM10, and nitrogen dioxide. It was found that the greatest contribution to the unfavorable environmental situation is made by three types of stationary sources: large heating networks, autonomous sources (enterprises and small businesses), and individual households. The main air pollutants whose concentrations exceed the limits are benzo(a)pyrene, formaldehyde, suspended particles PM2.5, PM10, and nitrogen dioxide. A comprehensive assessment of the content of various pollutants in the atmospheric air showed that levels of carcinogenic and non-carcinogenic risks to public health exceeded allowable levels. Priority pollutants in the atmosphere of Ulan-Ude whose concentrations create unacceptable levels of risk to public health are benzo(a)pyrene, suspended solids, nitrogen dioxide, PM2.5, PM10, formaldehyde, and black carbon. The levels of morbidity in Ulan-Ude were higher than the average for Buryatia by the main disease classes: respiratory organs&mdash;by 1.19 times, endocrine system&mdash;by 1.25 times, circulatory system&mdash;by 1.11 times, eye diseases&mdash;by 1.06 times, neoplasms&mdash;by 1.47 times, congenital anomalies, and deformations and chromosomal aberrations&mdash;by 1.63 times. There is an increase in the incidence of risk-related diseases of respiratory organs and the circulatory system. A strong correlation was found between this growth of morbidity and atmospheric air pollution in Ulan-Ude