Reducing ammonia(NH3) and nitrous oxide(N2O) emissions have great effects on mitigating nitrogen(N) nutrient loss and greenhouse gas emissions. Controlled release urea(CRU) can control the N release rate, which reduce...Reducing ammonia(NH3) and nitrous oxide(N2O) emissions have great effects on mitigating nitrogen(N) nutrient loss and greenhouse gas emissions. Controlled release urea(CRU) can control the N release rate, which reduces reactive N loss and increases nitrogen use efficiency relative to conventional urea(CU). However, the crucial factors influencing the responses of NH3and N2O emissions to CRU relative to CU are still unclear. In this study, we evaluated the responses of NH3and N2O emissions to CRU based on collected field data with a meta-analysis. CRU reduced the NH3and N2O emissions by 32.7 and 25.0% compared with CU, respectively. According to subgroup analysis, CRU presented better mitigation of NH3and N2O emissions in soils with pH 6.5–7.5(–47.9 and –23.7%) relative to either pH<6.5(–28.5and –21.4%) or pH>7.5(–29.3 and –17.3%), and in the rice season(–34.8 and –29.1%) relative to the wheat season(–19.8 and –22.8%). The responses of NH3and N2O emissions to CRU increased from rainfed(–30.5 and –17.0%) to irrigated(–32.5 and –22.9%), and then to paddy(–34.8 and –29.1%) systems. In addition, the response of N2O emission mitigation increased with increases in soil total nitrogen(TN);however, soil TN did not significantly affect the response of NH3volatilization. The reduction in NH3emission was greater in sandy-textured soil(–57.7%) relative to loam-textured(–32.9%) and clay-textured(–32.3%) soils, whereas soil texture did not affect N2O emission. Overall, CRU was a good option for reducing the NH3and N2O emissions relative to CU in agricultural production. This analysis improves our understanding of the crucial environmental and management factors influencing the mitigation of NH3and N2O emissions under CRU application, and these site-specific factors should be considered when applying CRU to reduce reactive N loss and increase NUE.展开更多
The title compound (C22H18N2O3) has been synthesized by the reaction of 3,4- dimethoxybenzaldehyde, malononitrile and 1-naphthol in ethanol in the presence of piperidine, and its structure was characterized by element...The title compound (C22H18N2O3) has been synthesized by the reaction of 3,4- dimethoxybenzaldehyde, malononitrile and 1-naphthol in ethanol in the presence of piperidine, and its structure was characterized by elemental analysis, IR, 1H NMR and X-ray single-crystal diffraction. The crystal belongs to monoclinic, space group C2/c with a = 24.221(6), b = 9.016(2), c = 17.003(5) ? b = 93.16(1), V = 3707(2) ?, Mr = 358.38, Z = 8, Dc = 1.284 g/cm3, m(MoKa) = 0.087 mm-1, F(000) = 1504, the final R = 0.0432 and wR = 0.1085. X-ray analysis reveals that the atoms of C(1), C(2), C(3), C(4), C(5) and O(1) form a boat-form six-membered ring in which the C(1)C(2) (1.349(3) ? is a C=C double bond.展开更多
The crystal structure of 1-(1-t-butyl-5-methyl-4-pyrazolylcarbonyl)-3,5-dimeth- yl-1H-yl-pyrazole ([C14H20N4O]2, Mr = 520.68) has been determined by single-crystal X-ray diffraction analysis. The crystal belongs to tr...The crystal structure of 1-(1-t-butyl-5-methyl-4-pyrazolylcarbonyl)-3,5-dimeth- yl-1H-yl-pyrazole ([C14H20N4O]2, Mr = 520.68) has been determined by single-crystal X-ray diffraction analysis. The crystal belongs to triclinic, space group P with a = 11.049(4), b = 11.313(4), c = 13.964(5) , ?= 69.085(6), b = 75.962(6), = 62.245(6), V = 1436.7(9) 3, Z = 2, Dc = 1.204 g/cm3, m = 0.079 mm-1, F(000) = 560, R = 0.0790 and wR = 0.1416 for 4729 unique reflections with 2635 observed ones (I > 2(I)). The results indicate that the pyrazole rings display aromaticity. The four pyrazole moieties are approximately coplanar in each case. The dihedral angles between planes 1 and 2, 3 and 4 are 40.99 and 10.77? respectively.展开更多
The Maximum Power Point Tracker (MPPT) is the optimum operating point of a photovoltaic module. It plays a very important role to obtain the maximum power of a solar panel as it allows an optimal use of a photovoltaic...The Maximum Power Point Tracker (MPPT) is the optimum operating point of a photovoltaic module. It plays a very important role to obtain the maximum power of a solar panel as it allows an optimal use of a photovoltaic system, regardless of irradiation and temperature variations. In this research, we present a novel technique to improve the control’s performances optimization of the system consisting of a photovoltaic panel, a buck converter and a load. Simulations of different parts of the system are developed under Matlab/Simulink, thus allowing a comparison between the performances of the three studied controllers: “Fuzzy TS”, “P&O” and “PSO”. The three algorithms of MPPT associated with these techniques are tested in different meteorological conditions. The obtained results, in different operating conditions, reveal a clear improvement of controlling performances of MPPT of a photovoltaic system when the PSO tracking technique is used.展开更多
Spatial control of lithium deposition is the most important issue in lithium-metal batteries because of the considerable control of lithium dendrite suppression via the uniform distribution of Li^(+)flux.Although seed...Spatial control of lithium deposition is the most important issue in lithium-metal batteries because of the considerable control of lithium dendrite suppression via the uniform distribution of Li^(+)flux.Although seed materials are crucial for the behavior of lithium deposition,in-depth studies on their physical and chemical control have not been conducted.Here,we describe a new design of seed structure comprising a wrinkled Cu/graphene substrate surrounded by copper(Ⅰ)oxide(Cu_(2)O)on a graphene grain boundary over a large area,which is fabricated by the oxidation of the Cu surface via graphene boundary defects by using chemical vapor deposition(CVD).Scanning and transmission electron microscopy results reveal that Cu_(2)O on the graphene boundary can render a preferential reaction with lithium during the first deposition and assist in the uniform deposition of lithium by preventing the agglomeration of lithium clusters during the second deposition.This two-step process is attributed to the degree of selectivity due to the difference in lithium affinity,which allows long-term electrochemical stability and a high rate capability via boundary effects.This study highlights the significance of the boundary effect,which can open new avenues for the formation of a large family of seed structures in lithium-metal batteries.展开更多
CO_(2) emulsions used for EOR have received a lot of interest because of its good performance on CO_(2)mobility reduction.However,most of them have been focusing on the high quality CO_(2) emulsion(high CO_(2) fractio...CO_(2) emulsions used for EOR have received a lot of interest because of its good performance on CO_(2)mobility reduction.However,most of them have been focusing on the high quality CO_(2) emulsion(high CO_(2) fraction),while CO_(2) emulsion with high water cut has been rarely researched.In this paper,we carried out a comprehensive experimental study of using high water cut CO_(2)/H_(2)O emulsion for enhancing oil recovery.Firstly,a nonionic surfactant,alkyl glycosides(APG),was selected to stabilize CO_(2)/H_(2)O emulsion,and the corresponding morphology and stability were evaluated with a transparent PVT cell.Subsequently,plugging capacity and apparent viscosity of CO_(2)/H_(2)O emulsion were measured systematically by a sand pack displacement apparatus connected with a 1.95-m long capillary tube.Furthermore,a high water cut(40 vol%) CO_(2)/H_(2)O emulsion was selected for flooding experiments in a long sand pack and a core sample,and the oil recovery,the rate of oil recovery,and the pressure gradients were analyzed.The results indicated that APG had a good performance on emulsifying and stabilizing CO_(2) emulsion.An inversion from H_(2)O/CO_(2) emulsion to CO_(2)/H_(2)O emulsion with the increase in water cut was confirmed.CO_(2)/H_(2)O emulsions with lower water cuts presented higher apparent viscosity,while the optimal plugging capacity of CO_(2)/H_(2)O emulsion occurred at a certain water cut.Eventually,the displacement using CO_(2)/H_(2)O emulsion provided 18.98% and 13.36% additional oil recovery than that using pure CO_(2) in long sand pack and core tests,respectively.This work may provide guidelines for EOR using CO_(2) emulsions with high water cut.展开更多
High surface energy of high-index facets endows nanocrystals with high activities and thus promotes potential applications such as highly efficient catalysts,special optical,electrical and magnetic devices.But the hig...High surface energy of high-index facets endows nanocrystals with high activities and thus promotes potential applications such as highly efficient catalysts,special optical,electrical and magnetic devices.But the high surface energy of the high-index facets usually drives them to grow faster than the other facets and finally disappear during the crystal growth,which leads the synthesis of nanocrystals with high-indexed facets exposed to be a great challenge.Herein,we introduced two routes to control the synthesis of-Fe2O3polyhedrons with different sets of high-index facets,one using different metal ions(Ni2+,Cu2+or Zn2+)as structure-directing agents and the other applying polymer surfactant sodium carboxymethyl cellulose(CMC)as additive.The growth process of high-index-Fe2O3polyhedrons was also discussed and possible growth mechanism was proposed.展开更多
The strategy of using Fe_(3)O_(4) amphiphilic Janus nanoparticles(Fe_(3)O_(4)@AJNPs)bearing b-cyclodextrin(b-CD)and aminopyridine(APD)functionalized polymethyl methacrylate(PGMA)to construct pH-stimuli responsive co-a...The strategy of using Fe_(3)O_(4) amphiphilic Janus nanoparticles(Fe_(3)O_(4)@AJNPs)bearing b-cyclodextrin(b-CD)and aminopyridine(APD)functionalized polymethyl methacrylate(PGMA)to construct pH-stimuli responsive co-assemblies through host-guest interactions between b-CD and APD was proposed.The spherical co-assemblies with an average diameter about 210nm were excellent magnetic responsive and quite stable even up to 2 months in deionized water.The pH-liable capability of these co-assemblies was revealed by disassembly of the formed superstructures with destruction of the built inclusion complexes.The disassembly process was monitored by SEM,TEM,DLS and fluorescent molecules probe.After disassembly of the co-assemblies caused by protonation of nitrogens in APD,hydrophobic PGMA-APD lacking of interactions with the Fe_(3)O_(4)@AJNPs chains was precipitated,and the remained Fe_(3)O_(4)@AJNPs turned to re-assemble to selfassemblies.Besides,the recyclable Fe_(3)O_(4)@APJNs could reassembly with additional PGMA-APD to build co-assemblies with a uniform morphology for several times.These pH-sensitive co-assemblies with high stability,good magnetic responsiveness and cytocompatibility could be used as pH-responsive vehicles within which to encapsulate drugs for subsequent controlled release.展开更多
基金financially supported by the Smart Fertilization Project (05)the National Key Research & Development Program of China (2022YFD1700605)。
文摘Reducing ammonia(NH3) and nitrous oxide(N2O) emissions have great effects on mitigating nitrogen(N) nutrient loss and greenhouse gas emissions. Controlled release urea(CRU) can control the N release rate, which reduces reactive N loss and increases nitrogen use efficiency relative to conventional urea(CU). However, the crucial factors influencing the responses of NH3and N2O emissions to CRU relative to CU are still unclear. In this study, we evaluated the responses of NH3and N2O emissions to CRU based on collected field data with a meta-analysis. CRU reduced the NH3and N2O emissions by 32.7 and 25.0% compared with CU, respectively. According to subgroup analysis, CRU presented better mitigation of NH3and N2O emissions in soils with pH 6.5–7.5(–47.9 and –23.7%) relative to either pH<6.5(–28.5and –21.4%) or pH>7.5(–29.3 and –17.3%), and in the rice season(–34.8 and –29.1%) relative to the wheat season(–19.8 and –22.8%). The responses of NH3and N2O emissions to CRU increased from rainfed(–30.5 and –17.0%) to irrigated(–32.5 and –22.9%), and then to paddy(–34.8 and –29.1%) systems. In addition, the response of N2O emission mitigation increased with increases in soil total nitrogen(TN);however, soil TN did not significantly affect the response of NH3volatilization. The reduction in NH3emission was greater in sandy-textured soil(–57.7%) relative to loam-textured(–32.9%) and clay-textured(–32.3%) soils, whereas soil texture did not affect N2O emission. Overall, CRU was a good option for reducing the NH3and N2O emissions relative to CU in agricultural production. This analysis improves our understanding of the crucial environmental and management factors influencing the mitigation of NH3and N2O emissions under CRU application, and these site-specific factors should be considered when applying CRU to reduce reactive N loss and increase NUE.
文摘The title compound (C22H18N2O3) has been synthesized by the reaction of 3,4- dimethoxybenzaldehyde, malononitrile and 1-naphthol in ethanol in the presence of piperidine, and its structure was characterized by elemental analysis, IR, 1H NMR and X-ray single-crystal diffraction. The crystal belongs to monoclinic, space group C2/c with a = 24.221(6), b = 9.016(2), c = 17.003(5) ? b = 93.16(1), V = 3707(2) ?, Mr = 358.38, Z = 8, Dc = 1.284 g/cm3, m(MoKa) = 0.087 mm-1, F(000) = 1504, the final R = 0.0432 and wR = 0.1085. X-ray analysis reveals that the atoms of C(1), C(2), C(3), C(4), C(5) and O(1) form a boat-form six-membered ring in which the C(1)C(2) (1.349(3) ? is a C=C double bond.
基金the Natural Science Foundation of Shandong Province (No. Y2003B01) and NNSFC (No. 20172031)
文摘The crystal structure of 1-(1-t-butyl-5-methyl-4-pyrazolylcarbonyl)-3,5-dimeth- yl-1H-yl-pyrazole ([C14H20N4O]2, Mr = 520.68) has been determined by single-crystal X-ray diffraction analysis. The crystal belongs to triclinic, space group P with a = 11.049(4), b = 11.313(4), c = 13.964(5) , ?= 69.085(6), b = 75.962(6), = 62.245(6), V = 1436.7(9) 3, Z = 2, Dc = 1.204 g/cm3, m = 0.079 mm-1, F(000) = 560, R = 0.0790 and wR = 0.1416 for 4729 unique reflections with 2635 observed ones (I > 2(I)). The results indicate that the pyrazole rings display aromaticity. The four pyrazole moieties are approximately coplanar in each case. The dihedral angles between planes 1 and 2, 3 and 4 are 40.99 and 10.77? respectively.
文摘The Maximum Power Point Tracker (MPPT) is the optimum operating point of a photovoltaic module. It plays a very important role to obtain the maximum power of a solar panel as it allows an optimal use of a photovoltaic system, regardless of irradiation and temperature variations. In this research, we present a novel technique to improve the control’s performances optimization of the system consisting of a photovoltaic panel, a buck converter and a load. Simulations of different parts of the system are developed under Matlab/Simulink, thus allowing a comparison between the performances of the three studied controllers: “Fuzzy TS”, “P&O” and “PSO”. The three algorithms of MPPT associated with these techniques are tested in different meteorological conditions. The obtained results, in different operating conditions, reveal a clear improvement of controlling performances of MPPT of a photovoltaic system when the PSO tracking technique is used.
基金funded by the Saudi Aramco-KAIST CO_(2)Management Centersupported by a grant from the National Research Foundation of Korea+1 种基金funded by the Ministry of Science,ICT,and Future Planning(Grant no.2021K1A4A8A01079356)supported by the National Research Foundation of Korea(NRF)fund(NRF-2020M3H4A3081874).
文摘Spatial control of lithium deposition is the most important issue in lithium-metal batteries because of the considerable control of lithium dendrite suppression via the uniform distribution of Li^(+)flux.Although seed materials are crucial for the behavior of lithium deposition,in-depth studies on their physical and chemical control have not been conducted.Here,we describe a new design of seed structure comprising a wrinkled Cu/graphene substrate surrounded by copper(Ⅰ)oxide(Cu_(2)O)on a graphene grain boundary over a large area,which is fabricated by the oxidation of the Cu surface via graphene boundary defects by using chemical vapor deposition(CVD).Scanning and transmission electron microscopy results reveal that Cu_(2)O on the graphene boundary can render a preferential reaction with lithium during the first deposition and assist in the uniform deposition of lithium by preventing the agglomeration of lithium clusters during the second deposition.This two-step process is attributed to the degree of selectivity due to the difference in lithium affinity,which allows long-term electrochemical stability and a high rate capability via boundary effects.This study highlights the significance of the boundary effect,which can open new avenues for the formation of a large family of seed structures in lithium-metal batteries.
基金The financial supports received from the National Natural Science Foundation of China(Nos.22178378,22127812)。
文摘CO_(2) emulsions used for EOR have received a lot of interest because of its good performance on CO_(2)mobility reduction.However,most of them have been focusing on the high quality CO_(2) emulsion(high CO_(2) fraction),while CO_(2) emulsion with high water cut has been rarely researched.In this paper,we carried out a comprehensive experimental study of using high water cut CO_(2)/H_(2)O emulsion for enhancing oil recovery.Firstly,a nonionic surfactant,alkyl glycosides(APG),was selected to stabilize CO_(2)/H_(2)O emulsion,and the corresponding morphology and stability were evaluated with a transparent PVT cell.Subsequently,plugging capacity and apparent viscosity of CO_(2)/H_(2)O emulsion were measured systematically by a sand pack displacement apparatus connected with a 1.95-m long capillary tube.Furthermore,a high water cut(40 vol%) CO_(2)/H_(2)O emulsion was selected for flooding experiments in a long sand pack and a core sample,and the oil recovery,the rate of oil recovery,and the pressure gradients were analyzed.The results indicated that APG had a good performance on emulsifying and stabilizing CO_(2) emulsion.An inversion from H_(2)O/CO_(2) emulsion to CO_(2)/H_(2)O emulsion with the increase in water cut was confirmed.CO_(2)/H_(2)O emulsions with lower water cuts presented higher apparent viscosity,while the optimal plugging capacity of CO_(2)/H_(2)O emulsion occurred at a certain water cut.Eventually,the displacement using CO_(2)/H_(2)O emulsion provided 18.98% and 13.36% additional oil recovery than that using pure CO_(2) in long sand pack and core tests,respectively.This work may provide guidelines for EOR using CO_(2) emulsions with high water cut.
基金supported by the National Basic Research Program of China(2011CB935800)the National Natural Science Foundation of China(21071076,21021062 and 51172106)
文摘High surface energy of high-index facets endows nanocrystals with high activities and thus promotes potential applications such as highly efficient catalysts,special optical,electrical and magnetic devices.But the high surface energy of the high-index facets usually drives them to grow faster than the other facets and finally disappear during the crystal growth,which leads the synthesis of nanocrystals with high-indexed facets exposed to be a great challenge.Herein,we introduced two routes to control the synthesis of-Fe2O3polyhedrons with different sets of high-index facets,one using different metal ions(Ni2+,Cu2+or Zn2+)as structure-directing agents and the other applying polymer surfactant sodium carboxymethyl cellulose(CMC)as additive.The growth process of high-index-Fe2O3polyhedrons was also discussed and possible growth mechanism was proposed.
基金supported by the National Natural Science Foundation of China(NSFC,21571134,31771037)the National Key Research and Development Program of China(2016YFC1102701)+1 种基金the Project in the Science and Technology Support Program of Sichuan Province(18ZDYF0823)the Project of Huimin Technology Research and Development of Chengdu(2015-HM01-00379-SF).
文摘The strategy of using Fe_(3)O_(4) amphiphilic Janus nanoparticles(Fe_(3)O_(4)@AJNPs)bearing b-cyclodextrin(b-CD)and aminopyridine(APD)functionalized polymethyl methacrylate(PGMA)to construct pH-stimuli responsive co-assemblies through host-guest interactions between b-CD and APD was proposed.The spherical co-assemblies with an average diameter about 210nm were excellent magnetic responsive and quite stable even up to 2 months in deionized water.The pH-liable capability of these co-assemblies was revealed by disassembly of the formed superstructures with destruction of the built inclusion complexes.The disassembly process was monitored by SEM,TEM,DLS and fluorescent molecules probe.After disassembly of the co-assemblies caused by protonation of nitrogens in APD,hydrophobic PGMA-APD lacking of interactions with the Fe_(3)O_(4)@AJNPs chains was precipitated,and the remained Fe_(3)O_(4)@AJNPs turned to re-assemble to selfassemblies.Besides,the recyclable Fe_(3)O_(4)@APJNs could reassembly with additional PGMA-APD to build co-assemblies with a uniform morphology for several times.These pH-sensitive co-assemblies with high stability,good magnetic responsiveness and cytocompatibility could be used as pH-responsive vehicles within which to encapsulate drugs for subsequent controlled release.
