16,214 research outputs found
Generation of spatially-separated spin entanglement in a triple quantum dot system
We propose a novel method for the creation of spatially-separated spin
entanglement by means of adiabatic passage of an external gate voltage in a
triple quantum dot system.Comment: 10 pages, 6 figure
Superabsorbent polymers (SAP) enhance efficient and eco-friendly production of corn (Zea mays L.) in drought affected areas of northern China
In arid and semiarid regions of northern China, there is an increasing interest in using reduced rate of chemical fertilizer along with water-saving superabsorbent polymer (SAP) for field crop production. The objective was to evaluate the effectiveness of different rates of SAP (low, 0.75; medium, 11.3 and high, 15.0 kg ha-1) against half amount of conventional standard rate of chemical fertilizer for summer corn (Zea mays L.) production in a drought-affected field of northern China. Corn yield increased following SAP application by 11.2% under low 18.8% under medium and 29.2% under high rate with only half amount (150 kg ha-1) of fertilizer compared with control plants, which received conventional standard fertilizer rate (300 kg ha-1). At the same time plant height, stem diameter, leaf area, biomass accumulation and relative water content as well as protein and sugar contents in the grain also increased significantly following SAP treatments. The optimum application of SAP in the study area would be 15 kg ha-1 as it brings progressive increase in corn growth and also maintain proper nutrients balance in the soil after harvest. Other rates are not sufficient to maintain proper plant growth or soil nutrient balance against half fertilizer. We suggest that, the application of SAP at 15 kg ha-1 plus only half the amount of conventional fertilizer rate (150 kg ha-1) would be a more appropriate practice for sustainable corn production under arid and semiarid conditions of northern China or the areas with similar ecologies.Key words: Corn, drought stress, fertilizer use efficiency, northern China, superabsorbent polymer
Antioxidant enzyme activities and lipid peroxidation in corn (Zea mays L.) following soil application of superabsorbent polymer at different fertilizer regimes
In arid and semiarid regions of northern China, there is an increasing interest in using reduced rate of inorganic fertilizer together with water-saving superabsorbent polymer (SAP) for field crop production. Thus, an efficient management of fertilizer and study of metabolic changes in response to SAP application is important for improved production of corn. 24 undisturbed soil lysimeters (35 cm in diameter and 150 cm in depth) were installed in a field lysimeter facility during 2010, to study yield and physiological mechanisms in corn (Zea mays L.) subjected to application (30 kg ha-1) or without application of SAP at different fertilization levels (standard, medium or 75% and low or 50% of conventional fertilization rate). The results show that the corn yield fell by 19.7% under medium and 37.7% under low fertilization; the application of SAP increased it significantly by 80.3%. Although SAP had marginal effect under standard fertilization, plants treated with SAP under reduced fertilization showed a significant decrease in superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX) and glutathione reductase (GR) activities in leaves when compared with control plants. Our results suggest that drought stress as well as fertilizer reduction leads to production of oxygen radicals, which results to oxidative stress in the plant and the application of superabsorbent polymer could conserve soil water and nutrients, making same available for plants to reduce oxidative stress and increase biomass accumulation, especially under reduced fertilization level.Key words: Antioxidant enzymes, lysimeter, corn, drought stress, superabsorbent polymer
Substantial emission reductions from Chinese power plants after the introduction of ultra-low emissions standards
In 2014, China introduced an ultra-low emissions (ULE) standards policy for renovating coal-fired power-generating units to limit SO2, NOx and particulate matter (PM) emissions to 35, 50 and 10 mg m−3, respectively. The ULE standard policy had ambitious levels (surpassing those of all other countries) and implementation timeline. We estimate emission reductions associated with the ULE policy by constructing a nationwide, unit-level, hourly-frequency emissions dataset using data from a continuous emissions monitoring systems network covering 96–98% of Chinese thermal power capacity during 2014–2017. We find that between 2014 and 2017 China’s annual power emissions of SO2, NOx and PM dropped by 65%, 60% and 72%, respectively. Our estimated emissions using actual monitoring data are 18–92% below other recent estimates. We detail the technologies used to meet the ULE standards and the determinants of compliance, underscoring the importance of ex post evaluation and providing insights for other countries wishing to reduce their power emissions
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