Worldwide, scarce water resources and substantial food demands require efficient water use and high yield.This study investigated whether irrigation frequency can be used to adjust soil moisture to increase grain yiel...Worldwide, scarce water resources and substantial food demands require efficient water use and high yield.This study investigated whether irrigation frequency can be used to adjust soil moisture to increase grain yield and water use efficiency(WUE) of high-yield maize under conditions of mulching and drip irrigation.A field experiment was conducted using three irrigation intervals in 2016: 6, 9, and 12 days(labeled D6, D9, and D12) and five irrigation intervals in 2017: 3, 6, 9, 12, and 15 days(D3, D6, D9, D12, and D15).In Xinjiang, an optimal irrigation quota is 540 mm for high-yield maize.The D3, D6, D9, D12, and D15 irrigation intervals gave grain yields of 19.7, 19.1–21.0, 18.8–20.0, 18.2–19.2, and 17.2 Mg ha^-1 and a WUE of 2.48, 2.53–2.80, 2.47–2.63, 2.34–2.45, and 2.08 kg m-3, respectively.Treatment D6 led to the highest soil water storage, but evapotranspiration and soil-water evaporation were lower than other treatments.These results show that irrigation interval D6 can help maintain a favorable soil-moisture environment in the upper-60-cm soil layer, reduce soilwater evaporation and evapotranspiration, and produce the highest yield and WUE.In this arid region and in other regions with similar soil and climate conditions, a similar irrigation interval would thus be beneficial for adjusting soil moisture to increase maize yield and WUE under conditions of mulching and drip irrigation.展开更多
In the feed injection zone of a multiphase fluidized bed reactor, nonuniform distribution exists due to the introduction of feed nozzle jets and circulating catalyst, which ultimately have an impact on the performance...In the feed injection zone of a multiphase fluidized bed reactor, nonuniform distribution exists due to the introduction of feed nozzle jets and circulating catalyst, which ultimately have an impact on the performance of the reactor. The transient sectional nonuniformity index (TSNI) is proposed as a new index to quantify the nonuniformity of solid distribution in both radial and circumferential dimensions at the same time, based on the transient solids holdup data in the feed zone. The temporal and spatial distributions of TSNI can more accurately reflect the changes in the real-time gas-solid distribution uniformity of the cross-sections and the efficiency of gas-solid contact in the feed injection zone. The feed injection zone can be divided into three regions according to the characteristics of TSNI: the bubble-influenced zone, the jet-influenced zone, and the acceleration zone. According to the numerical simulation results, it was analyzed that TSNI is highly correlated with operating conditions, such as nozzle gas velocity and catalyst circulation rate.展开更多
Engineering of crystal morphology affects the catalytic and adsorption properties of zeolitic materials.Considering the anisotropic diffusion of molecules derived from its topological features,MFI zeolite nanosheets w...Engineering of crystal morphology affects the catalytic and adsorption properties of zeolitic materials.Considering the anisotropic diffusion of molecules derived from its topological features,MFI zeolite nanosheets with short b-axis thickness are highly desired materials to reduce diffusion resistance.However,the design and development of eco-friendly synthesis protocols with reasonable cost and high efficiency remain elusive.Herein,we reported a systematic study on the synthesis of MFI nanosheets using urea as an additive.Both silicalite-1 and ZSM-5 zeolites(MFI type framework structure)with controllable b-thicknesses ranging from 50–200 nm were achieved by optimizing the synthetic parameters including water content,urea and SDA concentrations.The concentration of hydroxide anions was found to dominate the crystallization kinetics compared with the counterpart tetrapropylammonium cations(TPA^(+)).To facilitate the crystal growth of MFI zeolites in the presence of urea,the ratio OH−/SiO_(2)has to be higher than 0.2,independent of the TPA+concentration.The role of urea in the assistance of plate-like crystal formation through the inhibition of(010)facet growth was revealed by electron microscopy and infrared(IR)spectroscopy analyses.The developed strategy for morphological engineering is not limited to the MFI-type zeolite and can be applied to other frameworks depending on the intrinsic properties of additive molecules and the interactions between them.展开更多
基金research support from the National Key Research and Development Program of China (2016YFD0300110, 2016YFD0300101)the National Basic Research Program of China (2015CB150401)+2 种基金the National Natural Science Foundation of China (31360302)the Science and Technology Program of the Sixth Division of Xinjiang Construction Corps in China (1703)the Agricultural Science and Technology Innovation Program for financial support.
文摘Worldwide, scarce water resources and substantial food demands require efficient water use and high yield.This study investigated whether irrigation frequency can be used to adjust soil moisture to increase grain yield and water use efficiency(WUE) of high-yield maize under conditions of mulching and drip irrigation.A field experiment was conducted using three irrigation intervals in 2016: 6, 9, and 12 days(labeled D6, D9, and D12) and five irrigation intervals in 2017: 3, 6, 9, 12, and 15 days(D3, D6, D9, D12, and D15).In Xinjiang, an optimal irrigation quota is 540 mm for high-yield maize.The D3, D6, D9, D12, and D15 irrigation intervals gave grain yields of 19.7, 19.1–21.0, 18.8–20.0, 18.2–19.2, and 17.2 Mg ha^-1 and a WUE of 2.48, 2.53–2.80, 2.47–2.63, 2.34–2.45, and 2.08 kg m-3, respectively.Treatment D6 led to the highest soil water storage, but evapotranspiration and soil-water evaporation were lower than other treatments.These results show that irrigation interval D6 can help maintain a favorable soil-moisture environment in the upper-60-cm soil layer, reduce soilwater evaporation and evapotranspiration, and produce the highest yield and WUE.In this arid region and in other regions with similar soil and climate conditions, a similar irrigation interval would thus be beneficial for adjusting soil moisture to increase maize yield and WUE under conditions of mulching and drip irrigation.
基金support from the Technology Development Program of China National Petroleum Corporation(grant No.2023ZZ36).
文摘In the feed injection zone of a multiphase fluidized bed reactor, nonuniform distribution exists due to the introduction of feed nozzle jets and circulating catalyst, which ultimately have an impact on the performance of the reactor. The transient sectional nonuniformity index (TSNI) is proposed as a new index to quantify the nonuniformity of solid distribution in both radial and circumferential dimensions at the same time, based on the transient solids holdup data in the feed zone. The temporal and spatial distributions of TSNI can more accurately reflect the changes in the real-time gas-solid distribution uniformity of the cross-sections and the efficiency of gas-solid contact in the feed injection zone. The feed injection zone can be divided into three regions according to the characteristics of TSNI: the bubble-influenced zone, the jet-influenced zone, and the acceleration zone. According to the numerical simulation results, it was analyzed that TSNI is highly correlated with operating conditions, such as nozzle gas velocity and catalyst circulation rate.
基金the National Natural Science Foundation of China(NSFC)(No.22178389)S.M.acknowledges the support from NSFC(No.21975285)Z.X.Q.and S.M.acknowledge the support from PetroChina(Nos.PRIKY21084 and KYWX-21-021).
文摘Engineering of crystal morphology affects the catalytic and adsorption properties of zeolitic materials.Considering the anisotropic diffusion of molecules derived from its topological features,MFI zeolite nanosheets with short b-axis thickness are highly desired materials to reduce diffusion resistance.However,the design and development of eco-friendly synthesis protocols with reasonable cost and high efficiency remain elusive.Herein,we reported a systematic study on the synthesis of MFI nanosheets using urea as an additive.Both silicalite-1 and ZSM-5 zeolites(MFI type framework structure)with controllable b-thicknesses ranging from 50–200 nm were achieved by optimizing the synthetic parameters including water content,urea and SDA concentrations.The concentration of hydroxide anions was found to dominate the crystallization kinetics compared with the counterpart tetrapropylammonium cations(TPA^(+)).To facilitate the crystal growth of MFI zeolites in the presence of urea,the ratio OH−/SiO_(2)has to be higher than 0.2,independent of the TPA+concentration.The role of urea in the assistance of plate-like crystal formation through the inhibition of(010)facet growth was revealed by electron microscopy and infrared(IR)spectroscopy analyses.The developed strategy for morphological engineering is not limited to the MFI-type zeolite and can be applied to other frameworks depending on the intrinsic properties of additive molecules and the interactions between them.
