A very efficient and versatile solvent system, [HyEtPy]Cl–H2O, has been developed and used in the DABCO-catalyzed Morita–Baylis–Hillman reaction.

No abstract

No abstract

Adjusting the agricultural planting structure is one of the important means to realize agricultural water-saving, especially in arid inland river basin. In this paper, taking Shiyang River Basin as an example, on the basis of determining the crop water production function, a multi-objective optimization model was constructed, which comprehensively considered the maximization of economic benefits, the green water utilization rate and ecological benefits. The optimized planting structure was obtained by using GAMS (General Algebraic Modeling System) model solver. The results showed that: The common features of the three level years after optimization is that the sown area proportion of wheat, tubers, vegetables, fruits and cotton all increased, of which the sown area of fruits increased most by 5.30 × 10 4 ha. However, the sown area proportion of corn and oil-bearing crops decreased, of which the sown area of corn decreased most by 8.90 × 10 4 ha. Comparing of three level years, it is found that the impact of climate change on planting structure adjustment was relatively weak. With the decrease of precipitation, it is suggested to slightly decrease the sown area of wheat but slightly increase the sown area of tubers. The optimization results of planting structure were different in different counties. The average contribution rate of planting structure adjustment to total water-saving was 73.32%, indicating that planting structure adjustment was the key to water-saving. The water consumption of the same crop was different in different counties.

In northern China, precipitation fluctuates greatly and drought occurs frequently, which mark some of the important threats to agricultural and animal husbandry production. Understanding the meteorological dry-wet change and the evolution law of drought events in northern China has guiding significance for regional disaster prevention and mitigation. Based on the standardized precipitation index (SPI), this paper explored the spatio-temporal evolution of meteorological dry-wet in northern China. Our results showed that arid area (AA) and semi-arid area (SAA) in the west showed a trend of wetting at inter-annual and seasonal scales, while humid area (HA) and semi-humid area (SHA) in the east showed a different dry-wet changing trend at different seasons under the background of inter-annual drying. AA and HA showed obvious “reverse fluctuation” characteristics in summer. The drought frequency (DF) and drought intensity (DI) were high in the east and low in the west, and there was no significant difference in drought duration (DD) and drought severity (DS) between east and west. The DD, DS and DI of AA and SAA showed a decreasing trend, while the DD and DS of HA and SHA showed a slight increasing trend, and the DS decreased. In summer and autumn, the main influencing factors of drying in the east and wetting in the west were PNA, WP, PDO and TP1, and the fluctuations of NAO-SOI, NAO-AMO and PNA-NINO3.4 jointly determined the characteristics of SPI3 reverse fluctuations of HA and AA in summer.