A series of perovskite-like mixed oxides La2-xSrxMO4±λ(M =Cu, Co,Ni; x=0,1 ) was prepared and characterized using X-ray powder diffraction. The catalytic properties of these catalysts in NO decompositiori were t...A series of perovskite-like mixed oxides La2-xSrxMO4±λ(M =Cu, Co,Ni; x=0,1 ) was prepared and characterized using X-ray powder diffraction. The catalytic properties of these catalysts in NO decompositiori were tested. The results showed that LaSrNiO4-λ with K2NiF4 structure is very active and stable for the decomposition of NO.展开更多
Multiple nitrate transporter(NRT)genes exist in the genome of bread wheat,and it is of great importance to identify the elite NRT genes for N-efficient wheat cultivar breeding.A candidate gene association study(CGAS)o...Multiple nitrate transporter(NRT)genes exist in the genome of bread wheat,and it is of great importance to identify the elite NRT genes for N-efficient wheat cultivar breeding.A candidate gene association study(CGAS)of six N use efficiency(NUE)related traits(grain N concentration(GNC),straw N concentration(SNC),grain yield(GY),grain N accumulation(GNA),shoot total N accumulation(STN)and N harvest index(NHI))was performed based on SNPs in 46 NRT2 genes using a panel composed of 286 wheat cultivars.CGAS identified TaNRT2.1-6B as an elite NRT gene that is significantly associated with four(NHI,SNC,GNA and GY)of the six NUE-related traits simultaneously.TaNRT2.1-6B is located on the plasma membrane and acts as a dual-affinity NRT.The overexpression of TaNRT2.1-6B increased the N influx and root growth of wheat,whereas gene silence lines resulted in the opposite effects.The overexpression of TaNRT2.1-6B also improved GY and N accumulation of wheat under either limited or sufficient N conditions.The data provide the TaNRT2.1-6B gene and the two associated SNP markers as promising powerful tools for breeding wheat cultivars with high N uptake ability and NUE.展开更多
Inoculation density has a marked effect on nodulation and N fixation in soybean (Glycine max L.). Therefore, we conducted this study to determine the optimal inoculation density of Bradyhizobium japonicum SAY3-7 (SAY3...Inoculation density has a marked effect on nodulation and N fixation in soybean (Glycine max L.). Therefore, we conducted this study to determine the optimal inoculation density of Bradyhizobium japonicum SAY3-7 (SAY3-7) and Streptomyces griseoflavus P4 (P4) for plant growth, nodulation, and N fixation, and to investigate the effect of co-inoculation on selected soybean cultivars, using the optimal inoculation density. Nitrogen fixation, in terms of an acetylene reduction activity value, was measured using a flame ionization gas chromatograph. In this study, low-density single inoculation with P4 (10<sup>5</sup> or 10<sup>6</sup> cells mL<sup>-1</sup>) was associated with the highest plant biomass, compared with normal- and high-density single inoculation with P4 (10<sup>7</sup> or 10<sup>8</sup> cells mL<sup>-1</sup>). Moreover, low-density single or co-inoculations with SAY3-7 and/or P4 produced the highest nodule biomass and highest nitrogenase activity, compared with single or dual inoculation at other inoculation densities. Therefore, we evaluated low-density co-inoculation with P4 and SAY3-7, at the rate of 10<sup>5</sup> cells mL<sup>-1</sup>, on selected soybean cultivars. Low-density co-inoculation increased the plant biomass, compared with un-inoculated plants. The effects of single and co-inoculation on nodulation did not differ significantly for any of the cultivars, except “Yezin-9” in the first experiment and “Shan Seine” in the second experiment. Low-density inoculation with both bacteria increased N fixation by 15% - 75% for seven of the cultivars in the first experiment and by 15% - 39% for three of the cultivars in the second experiment, compared with single inoculation with SAY3-7. Based on the overall results, we concluded that low-density co-inoculation with P4 and SAY3-7 gave improved plant growth and N fixation.展开更多
Ab initio quantum mechanical method has been applied to nitrogen cages N_ 2n (n=12-18). Full geometry optimization, harmonic vibrational frequency and thermodynamics data for eight structures of nitrogen cages N_ 2n (...Ab initio quantum mechanical method has been applied to nitrogen cages N_ 2n (n=12-18). Full geometry optimization, harmonic vibrational frequency and thermodynamics data for eight structures of nitrogen cages N_ 2n (n=12-18) were performed at the HF/cc-pVDZ level. Cage N_ 24 (D_ 6d ), N_ 24 (O_h), N_ 26 (D_ 6d ), N_ 28 (T_d), N_ 30 (D_ 5h ), N_ 32 (D_ 3d ), N_ 36 (D_ 2d ) and N_ 36 (D_ 6h ) were found to be local minima on the potential energy surfaces. The computational results show that all the bond lengths of the eight structures are close to 0.145 nm and their bond energies E_ N-N are near to the experimental data of N-N single-bond. In addition, the thermochemical data of these nitrogen cages indicated that they are stable. It suggests that they are candidates for high energy density materials.展开更多
Nutritional characteristics determine tree stock quality to a considerable extent. Exponential fertilization can induce nutrient reserves within juvenile trees, but its validity on poplar is contingent on interaction ...Nutritional characteristics determine tree stock quality to a considerable extent. Exponential fertilization can induce nutrient reserves within juvenile trees, but its validity on poplar is contingent on interaction with a scientific irrigation regime due to limited water resources under global warming. In the present study, we raised 3200 Populus 9 euramericana cv. '74/76' cuttings under four irrigation regimes of 0(I0), 60 %(I60), 80 %(I80), and100 %(I100) of field capacity for soil moisture content with or without(control) the employment of nitrogen(N) addition delivered as exponential fertilization at the rate of 8 g N cutting^(-1)(E8) in an open-air nursery in Beijing, China. Both height and diameter increased with the increment of soil moisture ratio or in response to exponential fertilization(EF) without any interactive effects. In general, concentrations of N, phosphorus(P),and potassium(K) declined with time in stem but foliar N concentration did not change. Under the I100 regime, EF increased foliar N concentration relative to the control but failed to affect N concentration in stem in September, when both N concentration and N content were increased by EF under the I80 regime. Stem-K content and concentration by EF under the I80 regime also increased in September,therefore EF-treated cuttings had a higher ratio of K content in stem to that in whole plant(%ANAR). Vector diagnosis for nutritional status indicated that EF resulted in dilution of K concentration but induced a steady-state P uptake in leaves under all irrigation regimes. Therefore, EF of N addition could promote N uptake to leaves of P. 9 euramericana cv. '74/76' cuttings, but it had a null effect on N and P reserves in stem and impaired K reserves.In conclusion, the irrigation regime of 80 % field capacity of soil moisture content was suggested for the culture of juvenile P. 9 euramericana cv. '74/76' cuttings. As the interactive meaning, EF was also suggested for its excellent promotion on both N and K uptakes.展开更多
[Objective] The research aimed to study the determination of 16 kinds of OCPs in water by liquid-liquid extraction -GC. [Method] The new method for determining 16 kinds of OCPs in water by liquid-liquid extraction -GC...[Objective] The research aimed to study the determination of 16 kinds of OCPs in water by liquid-liquid extraction -GC. [Method] The new method for determining 16 kinds of OCPs in water by liquid-liquid extraction -GC was established, and the influencing factors such as nitrogen pressure and water bath temperature were discussed. [ Result] Detection limit of the method was from 3.2 to 14.1 ng/L, the relative standard deviation was between 4.0% and 9.6%, and the average recovery ranged from 80.8% to 106.0%. By optimizing nitrogen pressure and water bath temperature in the sample pretreatment process, when nitrogen pressure was +0.087 kPa, and water bath temperature was ±36 ℃, recovery effect of this method was better. [ Conclusion] The determination method had accurate qualitative and quantitative results, and met detection requirement of 16 kinds of OCPs in water.展开更多
The work addresses to the study of the molecular and crystal structure and properties of a new energyintensive compound 3,6-bis(2,2,2-trinitroethylnitramino)-1,2,4,5-tetrazine(NBTAT),first obtained by the authors in 2...The work addresses to the study of the molecular and crystal structure and properties of a new energyintensive compound 3,6-bis(2,2,2-trinitroethylnitramino)-1,2,4,5-tetrazine(NBTAT),first obtained by the authors in 2020.NBTAT compound crystallizes in the monoclinic system,space group P2(1)/n,density at room temperature 1.939 g/cm^(3).The energies of crystal packing and pairwise intermolecular interactions in NBTAT and its unnitrated analogue BTAT were calculated,and their comparative analysis was carried out.The enthalpy of formation of NBTAT molecules was calculated by quantum-chemical methods using Gaussian 09,and the enthalpy of formation of NBTAT in the solid phase(618 kJ/mol)was estimated.The energy capabilities of NBTAT as an oxidizer of solid composite propellants are estimated.It is shown that in metal-free compositions NBTAT is significantly superior to ammonium perchlorate(AP),dinitramide ammonium salt(ADN),HMX,BTAT at all stages of rocket systems,and is comparable to the superdense CL-20 yielding to the latter at the lower stages and slightly winning at the upper stages.展开更多
The Haber-Bosch process is the most widely used synthetic ammonia technology at present.Since its invention,it has provided an important guarantee for global food security.However,the traditional Haber-Bosch ammonia s...The Haber-Bosch process is the most widely used synthetic ammonia technology at present.Since its invention,it has provided an important guarantee for global food security.However,the traditional Haber-Bosch ammonia synthesis process consumes a lot of energy and causes serious environmental pollution.Under the serious pressure of energy and environment,a green,clean,and sustainable ammonia synthesis route is urgently needed.Electrochemical synthesis of ammonia is a green and mild new method for preparing ammonia,which can directly convert nitrogen or nitrate into ammonia using electricity driven by solar,wind,or water energy,without greenhouse gas and toxic gas emissions.Herein,the basic mechanism of the nitrogen reduction reaction(NRR)to ammonia and nitrate reduction reaction(NO_(3)^(-))to ammonia were discussed.The representative approaches and major technologies,such as lithium mediated electrolysis and solid oxide electrolysis cell(SOEC)electrolysis for NRR,high activity catalyst and advanced electrochemical device fabrication for(NO_(3)^(-))RR and electrochemical ammonia synthesis were summarized.Based on the above discussion and analysis,the main challenges and development directions for electrochemical ammonia synthesis were further proposed.展开更多
2-(Dinitromethylene)-1,3-diazacycloheptane (DNDH) was prepared by the reaction of 1,1-diamino-2,2-dinitro- ethylene (FOX-7) with 1,4-diaminoethane in NMP. Thermal decomposition behavior of DNDH was studied under...2-(Dinitromethylene)-1,3-diazacycloheptane (DNDH) was prepared by the reaction of 1,1-diamino-2,2-dinitro- ethylene (FOX-7) with 1,4-diaminoethane in NMP. Thermal decomposition behavior of DNDH was studied under the non-isothermal conditions with DSC method, and presents only one intensely exothermic decomposition process The kinetic equation of the decomposition reaction is da/dT= 103388× 3a2/3exp(--3.353 ×10^5/RT)/fl. The critical temperature of thermal explosion is 215.97℃. Specific heat capacity of DNDH was studied with micro-DSC method and theoretical calculation method, and the molar heat capacity is 215.40 Jomol-1,K-1 at 298.15 K. Adiabatic time-to-explosion was calculated to be 92.07 s. DNDH has same thermal stability to FOX-7.展开更多
A psychrophilic aerobic denitrifying bacterium,strain S1-1,was isolated from a biological aerated filter conducted for treatment of recirculating water in a marine aquaculture system.Strain S1-1 was preliminarily iden...A psychrophilic aerobic denitrifying bacterium,strain S1-1,was isolated from a biological aerated filter conducted for treatment of recirculating water in a marine aquaculture system.Strain S1-1 was preliminarily identified as Psychrobacter sp.based on the analysis of its 16S rRNA gene sequence,which showed 100% sequence similarity to that of Psychrobacter sp.TSBY-70.Strain S1-1 grew well either in high nitrate or high nitrite conditions with a removal of 100% nitrate or 63.50% nitrite,and the total nitrogen removal rates could reach to 46.48% and 31.89%,respectively.The results indicated that nitrate was mainly reduced in its logarithmic growth phase with a very low leve1 accumulation of nitrite,suggesting that the aerobic denitrification process of strain S1-1 occurred mainly in this phase.The GC-MS results showed that N 2 O was formed as the major intermediate during the aerobic denitrifying process of strain S1-1.Finally,factors affecting the growth of strain S1-1 and its aerobic denitrifying ability were also investigated.Results showed that the optimum aerobic denitrification conditions for strain S1-1 were sodium succinate as carbon source,C/N ratio15,salinity 10 g/L NaCl,incubation temperature 20°C and initial pH 6.5.展开更多
文摘A series of perovskite-like mixed oxides La2-xSrxMO4±λ(M =Cu, Co,Ni; x=0,1 ) was prepared and characterized using X-ray powder diffraction. The catalytic properties of these catalysts in NO decompositiori were tested. The results showed that LaSrNiO4-λ with K2NiF4 structure is very active and stable for the decomposition of NO.
基金funded by the National Natural Science Foundation of China(31972497).
文摘Multiple nitrate transporter(NRT)genes exist in the genome of bread wheat,and it is of great importance to identify the elite NRT genes for N-efficient wheat cultivar breeding.A candidate gene association study(CGAS)of six N use efficiency(NUE)related traits(grain N concentration(GNC),straw N concentration(SNC),grain yield(GY),grain N accumulation(GNA),shoot total N accumulation(STN)and N harvest index(NHI))was performed based on SNPs in 46 NRT2 genes using a panel composed of 286 wheat cultivars.CGAS identified TaNRT2.1-6B as an elite NRT gene that is significantly associated with four(NHI,SNC,GNA and GY)of the six NUE-related traits simultaneously.TaNRT2.1-6B is located on the plasma membrane and acts as a dual-affinity NRT.The overexpression of TaNRT2.1-6B increased the N influx and root growth of wheat,whereas gene silence lines resulted in the opposite effects.The overexpression of TaNRT2.1-6B also improved GY and N accumulation of wheat under either limited or sufficient N conditions.The data provide the TaNRT2.1-6B gene and the two associated SNP markers as promising powerful tools for breeding wheat cultivars with high N uptake ability and NUE.
文摘Inoculation density has a marked effect on nodulation and N fixation in soybean (Glycine max L.). Therefore, we conducted this study to determine the optimal inoculation density of Bradyhizobium japonicum SAY3-7 (SAY3-7) and Streptomyces griseoflavus P4 (P4) for plant growth, nodulation, and N fixation, and to investigate the effect of co-inoculation on selected soybean cultivars, using the optimal inoculation density. Nitrogen fixation, in terms of an acetylene reduction activity value, was measured using a flame ionization gas chromatograph. In this study, low-density single inoculation with P4 (10<sup>5</sup> or 10<sup>6</sup> cells mL<sup>-1</sup>) was associated with the highest plant biomass, compared with normal- and high-density single inoculation with P4 (10<sup>7</sup> or 10<sup>8</sup> cells mL<sup>-1</sup>). Moreover, low-density single or co-inoculations with SAY3-7 and/or P4 produced the highest nodule biomass and highest nitrogenase activity, compared with single or dual inoculation at other inoculation densities. Therefore, we evaluated low-density co-inoculation with P4 and SAY3-7, at the rate of 10<sup>5</sup> cells mL<sup>-1</sup>, on selected soybean cultivars. Low-density co-inoculation increased the plant biomass, compared with un-inoculated plants. The effects of single and co-inoculation on nodulation did not differ significantly for any of the cultivars, except “Yezin-9” in the first experiment and “Shan Seine” in the second experiment. Low-density inoculation with both bacteria increased N fixation by 15% - 75% for seven of the cultivars in the first experiment and by 15% - 39% for three of the cultivars in the second experiment, compared with single inoculation with SAY3-7. Based on the overall results, we concluded that low-density co-inoculation with P4 and SAY3-7 gave improved plant growth and N fixation.
文摘Ab initio quantum mechanical method has been applied to nitrogen cages N_ 2n (n=12-18). Full geometry optimization, harmonic vibrational frequency and thermodynamics data for eight structures of nitrogen cages N_ 2n (n=12-18) were performed at the HF/cc-pVDZ level. Cage N_ 24 (D_ 6d ), N_ 24 (O_h), N_ 26 (D_ 6d ), N_ 28 (T_d), N_ 30 (D_ 5h ), N_ 32 (D_ 3d ), N_ 36 (D_ 2d ) and N_ 36 (D_ 6h ) were found to be local minima on the potential energy surfaces. The computational results show that all the bond lengths of the eight structures are close to 0.145 nm and their bond energies E_ N-N are near to the experimental data of N-N single-bond. In addition, the thermochemical data of these nitrogen cages indicated that they are stable. It suggests that they are candidates for high energy density materials.
基金supported by the Specialized Research Fund for the Doctoral Program of Higher Education(20120014130001)the Eleventh Five-Year Plan Projects of National Science and Technology(Grant No.2006BAD24B01)
文摘Nutritional characteristics determine tree stock quality to a considerable extent. Exponential fertilization can induce nutrient reserves within juvenile trees, but its validity on poplar is contingent on interaction with a scientific irrigation regime due to limited water resources under global warming. In the present study, we raised 3200 Populus 9 euramericana cv. '74/76' cuttings under four irrigation regimes of 0(I0), 60 %(I60), 80 %(I80), and100 %(I100) of field capacity for soil moisture content with or without(control) the employment of nitrogen(N) addition delivered as exponential fertilization at the rate of 8 g N cutting^(-1)(E8) in an open-air nursery in Beijing, China. Both height and diameter increased with the increment of soil moisture ratio or in response to exponential fertilization(EF) without any interactive effects. In general, concentrations of N, phosphorus(P),and potassium(K) declined with time in stem but foliar N concentration did not change. Under the I100 regime, EF increased foliar N concentration relative to the control but failed to affect N concentration in stem in September, when both N concentration and N content were increased by EF under the I80 regime. Stem-K content and concentration by EF under the I80 regime also increased in September,therefore EF-treated cuttings had a higher ratio of K content in stem to that in whole plant(%ANAR). Vector diagnosis for nutritional status indicated that EF resulted in dilution of K concentration but induced a steady-state P uptake in leaves under all irrigation regimes. Therefore, EF of N addition could promote N uptake to leaves of P. 9 euramericana cv. '74/76' cuttings, but it had a null effect on N and P reserves in stem and impaired K reserves.In conclusion, the irrigation regime of 80 % field capacity of soil moisture content was suggested for the culture of juvenile P. 9 euramericana cv. '74/76' cuttings. As the interactive meaning, EF was also suggested for its excellent promotion on both N and K uptakes.
文摘[Objective] The research aimed to study the determination of 16 kinds of OCPs in water by liquid-liquid extraction -GC. [Method] The new method for determining 16 kinds of OCPs in water by liquid-liquid extraction -GC was established, and the influencing factors such as nitrogen pressure and water bath temperature were discussed. [ Result] Detection limit of the method was from 3.2 to 14.1 ng/L, the relative standard deviation was between 4.0% and 9.6%, and the average recovery ranged from 80.8% to 106.0%. By optimizing nitrogen pressure and water bath temperature in the sample pretreatment process, when nitrogen pressure was +0.087 kPa, and water bath temperature was ±36 ℃, recovery effect of this method was better. [ Conclusion] The determination method had accurate qualitative and quantitative results, and met detection requirement of 16 kinds of OCPs in water.
基金The Ministry of Science and Higher Education of the Russian Federation(Agreement with Zelinsky Institute of Organic Chemistry RAS No 075-15-2020-803).
文摘The work addresses to the study of the molecular and crystal structure and properties of a new energyintensive compound 3,6-bis(2,2,2-trinitroethylnitramino)-1,2,4,5-tetrazine(NBTAT),first obtained by the authors in 2020.NBTAT compound crystallizes in the monoclinic system,space group P2(1)/n,density at room temperature 1.939 g/cm^(3).The energies of crystal packing and pairwise intermolecular interactions in NBTAT and its unnitrated analogue BTAT were calculated,and their comparative analysis was carried out.The enthalpy of formation of NBTAT molecules was calculated by quantum-chemical methods using Gaussian 09,and the enthalpy of formation of NBTAT in the solid phase(618 kJ/mol)was estimated.The energy capabilities of NBTAT as an oxidizer of solid composite propellants are estimated.It is shown that in metal-free compositions NBTAT is significantly superior to ammonium perchlorate(AP),dinitramide ammonium salt(ADN),HMX,BTAT at all stages of rocket systems,and is comparable to the superdense CL-20 yielding to the latter at the lower stages and slightly winning at the upper stages.
文摘The Haber-Bosch process is the most widely used synthetic ammonia technology at present.Since its invention,it has provided an important guarantee for global food security.However,the traditional Haber-Bosch ammonia synthesis process consumes a lot of energy and causes serious environmental pollution.Under the serious pressure of energy and environment,a green,clean,and sustainable ammonia synthesis route is urgently needed.Electrochemical synthesis of ammonia is a green and mild new method for preparing ammonia,which can directly convert nitrogen or nitrate into ammonia using electricity driven by solar,wind,or water energy,without greenhouse gas and toxic gas emissions.Herein,the basic mechanism of the nitrogen reduction reaction(NRR)to ammonia and nitrate reduction reaction(NO_(3)^(-))to ammonia were discussed.The representative approaches and major technologies,such as lithium mediated electrolysis and solid oxide electrolysis cell(SOEC)electrolysis for NRR,high activity catalyst and advanced electrochemical device fabrication for(NO_(3)^(-))RR and electrochemical ammonia synthesis were summarized.Based on the above discussion and analysis,the main challenges and development directions for electrochemical ammonia synthesis were further proposed.
基金Project supported by the National Natural Science Foundation of China (No. 20803058), the Basal Science Foundation of National Defense (No. B 0920110005 ) and the Education Committee Foundation of S haanxi Province (Nos. 2010J K881, 09J K820).
文摘2-(Dinitromethylene)-1,3-diazacycloheptane (DNDH) was prepared by the reaction of 1,1-diamino-2,2-dinitro- ethylene (FOX-7) with 1,4-diaminoethane in NMP. Thermal decomposition behavior of DNDH was studied under the non-isothermal conditions with DSC method, and presents only one intensely exothermic decomposition process The kinetic equation of the decomposition reaction is da/dT= 103388× 3a2/3exp(--3.353 ×10^5/RT)/fl. The critical temperature of thermal explosion is 215.97℃. Specific heat capacity of DNDH was studied with micro-DSC method and theoretical calculation method, and the molar heat capacity is 215.40 Jomol-1,K-1 at 298.15 K. Adiabatic time-to-explosion was calculated to be 92.07 s. DNDH has same thermal stability to FOX-7.
基金supported by the Knowledge Innova-tion Program of the Chinese Academy of Sciences(No.KJCX2-YW-L08)
文摘A psychrophilic aerobic denitrifying bacterium,strain S1-1,was isolated from a biological aerated filter conducted for treatment of recirculating water in a marine aquaculture system.Strain S1-1 was preliminarily identified as Psychrobacter sp.based on the analysis of its 16S rRNA gene sequence,which showed 100% sequence similarity to that of Psychrobacter sp.TSBY-70.Strain S1-1 grew well either in high nitrate or high nitrite conditions with a removal of 100% nitrate or 63.50% nitrite,and the total nitrogen removal rates could reach to 46.48% and 31.89%,respectively.The results indicated that nitrate was mainly reduced in its logarithmic growth phase with a very low leve1 accumulation of nitrite,suggesting that the aerobic denitrification process of strain S1-1 occurred mainly in this phase.The GC-MS results showed that N 2 O was formed as the major intermediate during the aerobic denitrifying process of strain S1-1.Finally,factors affecting the growth of strain S1-1 and its aerobic denitrifying ability were also investigated.Results showed that the optimum aerobic denitrification conditions for strain S1-1 were sodium succinate as carbon source,C/N ratio15,salinity 10 g/L NaCl,incubation temperature 20°C and initial pH 6.5.