Based on the principle of ENV 196-4 ＂Methods of testing cement - Part 4 Quantitative determination of constituents or Chinese Standard GB/12960-2007 Quantitative measurement of mineral admixtures in cement, methods w...Based on the principle of ENV 196-4 ＂Methods of testing cement - Part 4 Quantitative determination of constituents or Chinese Standard GB/12960-2007 Quantitative measurement of mineral admixtures in cement, methods were developed for quantitative determination of fly ash, slag and limestone powder in fresh cement pastes, mortars and concretes. Limestone powder was determined using thermal analysis method. The residue content of fly ash on an 80um sieve, and silt contents of aggregate were also considered during the quantitative determination of mineral composition of quaternary cementitious system. With the developed methods, the deviations between the measured and the actual mineral contents of the constituent in the eemantitious material in fresh cement paste, mortar and concrete, were within 3%.展开更多
Seismic rupture produced by active faulting causes ground surface fracturing and seriously damages buildings.However,the fracture traces are usually indistinct or non-visible because of complicated deformations in Qua...Seismic rupture produced by active faulting causes ground surface fracturing and seriously damages buildings.However,the fracture traces are usually indistinct or non-visible because of complicated deformations in Quaternary unconsolidated materials,so their upper parts can hardly be discovered on exploratory trenches.The aim of this paper is to study the types of fault rupture and displacement in different loose deposit beds from a joint view of mega-,meso-,and microscopic scales,and to find the mark and method for timing the palaeoseismic rupture on exploratory trenches.展开更多
Li_(3)PO_(4)@Li_(0.99)K_(0.01)Ni_(0.83)Co_(0.11)Mn_(O.06)O_(2)(NCM-KP) cathode powders are synthesized via K^(+)doping in calcination processes and H_3PO_4 coating in sol-gel processes.K^(+) precisely enters into the ...Li_(3)PO_(4)@Li_(0.99)K_(0.01)Ni_(0.83)Co_(0.11)Mn_(O.06)O_(2)(NCM-KP) cathode powders are synthesized via K^(+)doping in calcination processes and H_3PO_4 coating in sol-gel processes.K^(+) precisely enters into the lattice to widen the(003) plane to 0.4746 nm with a lower cationic disordered degree of 1.87%.Moreover,the surface residual lithium salts are treated by H_3PO_4 to generate a uniform Li_(3)PO_(4) coating layer of approximately 11.41 nm,which completely covers on the surface of secondary spherical particles to improve the interfacial stability.At 25℃,the NCM-KP electrode delivers a discharge specific capacity of 148.9 mAh·g^(-1) with a remarkable capacity retention ratio of 84.1% after 200 cycles at 1.0C and retains a high reversible specific capacity of 154.4 mAh·g^(-1) at 5.0C.Even at 1.0C and 60℃,it can maintain a reversible discharge specific capacity of 114.6 mAh·g^(-1) with 0.21% of capacity decay per cycle after 200 cycles,which is significantly lower than 0.40% for the pristine NCM powders.Importantly,the charge transfer resistance of 238.89 Ω for the NCM-KP electrode is significantly lower than 947.41 Ω for the pristine NCM one by restricting the interfacial side reactions.Therefore,combining K+doping and Li_(3)PO_(4) coating is an effective strategy to enable the significant improvement of the electrochemical property of high-nickel cathode materials,which may be mainly attributed to the widened diffusion pathway and the formed Li_(3)PO_(4) protective layer,thus promoting Li~+diffusion rate and preventing the erosion of HF.展开更多
Ni-Ti-based shape memory alloys(SMAs)have found widespread use in the last 70 years,but improving their functional stability remains a key quest for more robust and advanced applications.Named for their ability to ret...Ni-Ti-based shape memory alloys(SMAs)have found widespread use in the last 70 years,but improving their functional stability remains a key quest for more robust and advanced applications.Named for their ability to retain their processed shape as a result of a reversible martensitic transformation,SMAs are highly sensitive to compositional variations.Alloying with ternary and quaternary elements to finetune the lattice parameters and the thermal hysteresis of an SMA,therefore,becomes a challenge in materials exploration.Combinatorial materials science allows streamlining of the synthesis process and data management from multiple characterization techniques.In this study,a composition spread of Ni-Ti-Cu-V thin-film library was synthesized by magnetron co-sputtering on a thermally oxidized Si wafer.Composition-dependent phase transformation temperature and microstructure were investigated and determined using high-throughput wavelength dispersive spectroscopy,synchrotron X-ray diffraction,and temperature-dependent resistance measurements.Of the 177 compositions in the materials library,32 were observed to have shape memory effect,of which five had zero or near-zero thermal hysteresis.These compositions provide flexibility in the operating temperature regimes that they can be used in.A phase map for the quaternary system and correlations of functional properties are discussed w让h respect to the local microstructure and composition of the thin-film library.展开更多
Quaternary alloys Mg2Sn0.4Si0.6-xGex （x=0, 0.02, 0.05, 0.08 0.1, and 0.2） were prepared using induction melting followed by hot-pressing. Relative densities of the sintered samples were over 97% of the theoretical v...Quaternary alloys Mg2Sn0.4Si0.6-xGex （x=0, 0.02, 0.05, 0.08 0.1, and 0.2） were prepared using induction melting followed by hot-pressing. Relative densities of the sintered samples were over 97% of the theoretical values. Multiple phases were detected in the samples. It was found that the Seebeck coefficient was sensitive to the content of Mg2Ge and a maximum value of about 350 μV-K^-1 was obtained. The introduction of Ge increases the electrical conductivity and the thermal conductivity simultaneously. The mechanism of this phenomenon was discussed. A maximum dimensionless figure of merit, ZT, of about 0.28 was obtained for Mg2Sn0.4Si0.55Ge0.05 at 550 K.展开更多
Reducing the emission of agrochemicals hazardous to the environment and human health is one of the key targets of the UN’s Sustainable Development Goal 12.Herein,we report a kind of quaternary ammonium pesticides wit...Reducing the emission of agrochemicals hazardous to the environment and human health is one of the key targets of the UN’s Sustainable Development Goal 12.Herein,we report a kind of quaternary ammonium pesticides with an acid-cleavable silaketal linkage on their backbones that enables control of hydrolysis.These pesticides possess outstanding bactericidal and insecticidal properties but become harmless to humans and other organisms after hydrolysis.Depending on the conditions of use,the hydrolytic process can be controlled over the time range of 10 min to 3 months.Both laboratory simulations and agricultural field demonstrations confirm that these pesticides can effectively protect crops from bacterial diseases and pests.At the sametime,single-dose intragastric administration using diisopropylsilyloxy bisquaternary ammonium salt 9(ISBQAS-9)in mice demonstrates its safety for multiple organs.Owing to the advantages of controllable degradability,environmental friendliness,and the low financial cost of these pesticides,this welldesigned strategy holds great promise for the generation of environmentally harmless pesticides and the development of green agriculture.展开更多
基金Funded by the National Natural Science Foundation of China(50978093 and 51072050)the National Key Research Program(973 Project)(No.2009CB6231001)
文摘Based on the principle of ENV 196-4 ＂Methods of testing cement - Part 4 Quantitative determination of constituents or Chinese Standard GB/12960-2007 Quantitative measurement of mineral admixtures in cement, methods were developed for quantitative determination of fly ash, slag and limestone powder in fresh cement pastes, mortars and concretes. Limestone powder was determined using thermal analysis method. The residue content of fly ash on an 80um sieve, and silt contents of aggregate were also considered during the quantitative determination of mineral composition of quaternary cementitious system. With the developed methods, the deviations between the measured and the actual mineral contents of the constituent in the eemantitious material in fresh cement paste, mortar and concrete, were within 3%.
基金This project was sponsored by the Joint Earthquake Science Foundation under Contract No. 197007by the Doctoral Program Foundation of Institution of Higher Education, State Education Commission of China
文摘Seismic rupture produced by active faulting causes ground surface fracturing and seriously damages buildings.However,the fracture traces are usually indistinct or non-visible because of complicated deformations in Quaternary unconsolidated materials,so their upper parts can hardly be discovered on exploratory trenches.The aim of this paper is to study the types of fault rupture and displacement in different loose deposit beds from a joint view of mega-,meso-,and microscopic scales,and to find the mark and method for timing the palaeoseismic rupture on exploratory trenches.
基金financially supported by the National Natural Science Foundation of China (Nos.52274292 and 51874046)the Outstanding Youth Foundation of Hubei Province (No.2020CFA090)。
文摘Li_(3)PO_(4)@Li_(0.99)K_(0.01)Ni_(0.83)Co_(0.11)Mn_(O.06)O_(2)(NCM-KP) cathode powders are synthesized via K^(+)doping in calcination processes and H_3PO_4 coating in sol-gel processes.K^(+) precisely enters into the lattice to widen the(003) plane to 0.4746 nm with a lower cationic disordered degree of 1.87%.Moreover,the surface residual lithium salts are treated by H_3PO_4 to generate a uniform Li_(3)PO_(4) coating layer of approximately 11.41 nm,which completely covers on the surface of secondary spherical particles to improve the interfacial stability.At 25℃,the NCM-KP electrode delivers a discharge specific capacity of 148.9 mAh·g^(-1) with a remarkable capacity retention ratio of 84.1% after 200 cycles at 1.0C and retains a high reversible specific capacity of 154.4 mAh·g^(-1) at 5.0C.Even at 1.0C and 60℃,it can maintain a reversible discharge specific capacity of 114.6 mAh·g^(-1) with 0.21% of capacity decay per cycle after 200 cycles,which is significantly lower than 0.40% for the pristine NCM powders.Importantly,the charge transfer resistance of 238.89 Ω for the NCM-KP electrode is significantly lower than 947.41 Ω for the pristine NCM one by restricting the interfacial side reactions.Therefore,combining K+doping and Li_(3)PO_(4) coating is an effective strategy to enable the significant improvement of the electrochemical property of high-nickel cathode materials,which may be mainly attributed to the widened diffusion pathway and the formed Li_(3)PO_(4) protective layer,thus promoting Li~+diffusion rate and preventing the erosion of HF.
基金The author thanks Tieren Gao,Peer Decker,Alan Savan,and Manfred Wuttig for fruitful discussions.The authors gratefully acknowledge funding support by the National Science Foundation Graduate Research Fellowship Program(DGE 1322106).
文摘Ni-Ti-based shape memory alloys(SMAs)have found widespread use in the last 70 years,but improving their functional stability remains a key quest for more robust and advanced applications.Named for their ability to retain their processed shape as a result of a reversible martensitic transformation,SMAs are highly sensitive to compositional variations.Alloying with ternary and quaternary elements to finetune the lattice parameters and the thermal hysteresis of an SMA,therefore,becomes a challenge in materials exploration.Combinatorial materials science allows streamlining of the synthesis process and data management from multiple characterization techniques.In this study,a composition spread of Ni-Ti-Cu-V thin-film library was synthesized by magnetron co-sputtering on a thermally oxidized Si wafer.Composition-dependent phase transformation temperature and microstructure were investigated and determined using high-throughput wavelength dispersive spectroscopy,synchrotron X-ray diffraction,and temperature-dependent resistance measurements.Of the 177 compositions in the materials library,32 were observed to have shape memory effect,of which five had zero or near-zero thermal hysteresis.These compositions provide flexibility in the operating temperature regimes that they can be used in.A phase map for the quaternary system and correlations of functional properties are discussed w让h respect to the local microstructure and composition of the thin-film library.
基金supported by the National Natural Science Foundation of China (No.50522203, 50731006)the National Basic Research Program of China (No.2007CB607502)
文摘Quaternary alloys Mg2Sn0.4Si0.6-xGex （x=0, 0.02, 0.05, 0.08 0.1, and 0.2） were prepared using induction melting followed by hot-pressing. Relative densities of the sintered samples were over 97% of the theoretical values. Multiple phases were detected in the samples. It was found that the Seebeck coefficient was sensitive to the content of Mg2Ge and a maximum value of about 350 μV-K^-1 was obtained. The introduction of Ge increases the electrical conductivity and the thermal conductivity simultaneously. The mechanism of this phenomenon was discussed. A maximum dimensionless figure of merit, ZT, of about 0.28 was obtained for Mg2Sn0.4Si0.55Ge0.05 at 550 K.
基金the National Natural Science Foundation of China(grant nos.21825503 and 22335008).
文摘Reducing the emission of agrochemicals hazardous to the environment and human health is one of the key targets of the UN’s Sustainable Development Goal 12.Herein,we report a kind of quaternary ammonium pesticides with an acid-cleavable silaketal linkage on their backbones that enables control of hydrolysis.These pesticides possess outstanding bactericidal and insecticidal properties but become harmless to humans and other organisms after hydrolysis.Depending on the conditions of use,the hydrolytic process can be controlled over the time range of 10 min to 3 months.Both laboratory simulations and agricultural field demonstrations confirm that these pesticides can effectively protect crops from bacterial diseases and pests.At the sametime,single-dose intragastric administration using diisopropylsilyloxy bisquaternary ammonium salt 9(ISBQAS-9)in mice demonstrates its safety for multiple organs.Owing to the advantages of controllable degradability,environmental friendliness,and the low financial cost of these pesticides,this welldesigned strategy holds great promise for the generation of environmentally harmless pesticides and the development of green agriculture.
