Hydraulic fracturing is a mature and effectivemethod for deep oil and gas production,which provides a foundation for deep oil and gas production.One of the key aspects of implementing hydraulic fracturing technology l...Hydraulic fracturing is a mature and effectivemethod for deep oil and gas production,which provides a foundation for deep oil and gas production.One of the key aspects of implementing hydraulic fracturing technology lies in understanding mechanics response characteristics of rocks in deep reservoirs under complex stress conditions.In this work,based on outcrop core samples,high-stress triaxial compression tests were designed to simulate the rock mechanics behavior of deep reservoirs in Bozhong Sag.Additionally,this study analyzes the deformation and damage law for rock under different stress conditions.Wherein,with a particular focus on combining energy dissipation theory to further understand damage law for deep reservoirs.The experimental results show that regardless of stress conditions,the process of deformation/failure of deep-seated reservoirs goes through five stages:Fracture compaction,newfracture formation,stable fracture expansion,unstable fracture expansion,and post-peak residual deformation.Under different stress conditions,the energy change laws of specimens are similar.The energy dissipation process of rocks corresponds closely to the trend of deformation-failure curve,then displays distinctive stage characteristics.Wherein,in stage of rock fracture compaction,the input energy curve is approximately coincident with the elastic strain energy curve,while the dissipation energy curve remains near zero.With the increase of strain,the growth rate of elastic strain energy increases gradually,but with the deformation entering the crack propagation stage,the growth rate of elastic strain energy slows down and the dissipation energy increases gradually.Finally,in the post-peak stage,rock fracture releases a lot of energy,which leads to the sharp decline of elastic strain energy curve.In addition,the introduction of damage variable D quantifies the analysis of the extent of failure for rocks.During the process of increasing strain,rock damage exhibits nonlinear growth with increasing stress.展开更多
In this work,a“cyclopentanone-vanillin”strategy was proposed for the preparation of jet fuel range cycloalkanes from lignocellulose-derived ketones and lignin-derived aldehydes via aldol condensation and hydrodeoxyg...In this work,a“cyclopentanone-vanillin”strategy was proposed for the preparation of jet fuel range cycloalkanes from lignocellulose-derived ketones and lignin-derived aldehydes via aldol condensation and hydrodeoxygenation(HDO).Ethanolamine lactate ionic liquid(LAIL)exhibited excellent catalytic activity in the aldol condensation of cyclopentanone and vanillin.Desired mono-condensation and bicondensation products were obtained with yield of 95.2%at 100℃.It is found that the synergy effects between amino group of ethanolamine and hydroxyl group of lactic acid play a key role in the aldol condensation.The condensation products were converted into cycloalkanes by HDO over 5%Pd/Nb_(2)O_(5)catalyst.The density of the obtained HDO products is 0.89 g/cm^(3)and the freezing point is lower than-60℃.These results suggest that the resulted cycloalkanes can be used as additives to improve the density and low-temperature fluidity of the jet fuels.展开更多
Acid soils occupy approximately 50% of potentially arable lands.Improving crop productivity in acid soils,therefore,will be crucial for ensuring food security and agricultural sustainability.High soil acidity often co...Acid soils occupy approximately 50% of potentially arable lands.Improving crop productivity in acid soils,therefore,will be crucial for ensuring food security and agricultural sustainability.High soil acidity often coexists with phosphorus(P) deficiency and aluminum(Al) toxicity,a combination that severely impedes crop growth and yield across wide areas.As roots explore soil for the nutrients and water required for plant growth and development,they also sense and respond to below-ground stresses.Within the terrestrial context of widespread P deficiency and Al toxicity pressures,plants,particularly roots,have evolved a variety of mechanisms for adapting to these stresses.As legumes,soybean(Glycine max) plants may acquire nitrogen(N) through symbiotic nitrogen fixation(SNF),an adaptation that can be useful for mitigating excessive N fertilizer use,either directly as leguminous crop participants in rotation and intercropping systems,or secondarily as green manure cover crops.In this review,we investigate legumes,especially soybean,for recent advances in our understanding of root-based mechanisms linked with root architecture modification,exudation and symbiosis,together with associated genetic and molecular strategies in adaptation to individual and/or interacting P and Al conditions in acid soils.We propose that breeding legume cultivars with superior nutrient efficiency and/or Al tolerance traits through genetic selection might become a potentially powerful strategy for producing crop varieties capable of maintaining or improving yields in more stressful soil conditions subjected to increasingly challenging environmental conditions.展开更多
Superior inbred lines are central to maize breeding as sources of natural variation.Although many elite lines have been sequenced,less sequencing attention has been paid to newly developed lines.We constructed a genom...Superior inbred lines are central to maize breeding as sources of natural variation.Although many elite lines have been sequenced,less sequencing attention has been paid to newly developed lines.We constructed a genome assembly of the elite inbred line KA105,which has recently been developed by an arti-ficial breeding population named Shaan A and has shown desirable characteristics for breeding.Its pedigree showed genetic divergence from B73 and other lines in its pedigree.Comparison with the B73 reference genome revealed extensive structural variation,58 presence/absence variation(PAV)genes,and 1023 expanded gene families,some of which may be associated with disease resistance.A network-based integrative analysis of stress-induced transcriptomes identified 13 KA105-specific PAV genes,of which eight were induced by at least one kind of stress,participating in gene modules responding to stress such as drought and southern leaf blight disease.More than 200,000 gene pairs were differentially correlated between KA105 and B73 during kernel development.The KA105 reference genome and transcriptome atlas are a resource for further germplasm improvement and surveys of maize genomic variation and gene function.展开更多
Background:Long-chain non-coding RNA(lncRNA)LINC00609 is a potential tumor suppressor,but the mechanism of action in non-small cell lung cancer(NSCLC)is yet to be understood.Objectives:The effects of LINC00609 on A549...Background:Long-chain non-coding RNA(lncRNA)LINC00609 is a potential tumor suppressor,but the mechanism of action in non-small cell lung cancer(NSCLC)is yet to be understood.Objectives:The effects of LINC00609 on A549 cell proliferation,apoptosis,and cell cycle arrest were investigated.Methods:The LINC00609 levels in NSCLC and normal tissues were analyzed by bioinformatics.Expressions of LINC00609,miR-128-3p,and Rho family GTPase 3(RND3)in NSCLC cells(A549)were determined by qRT-PCR.Bioinformatics analysis predicted target genes and dual-luciferase reporter assays to ensure that LINC00609 targeted miR-128-3p and miR-128-3p targeted RND3.The proliferation of cells was determined using EDU and CCK-8.Flow cytometry was used to evaluate cell apoptosis rate and cell cycle.The western blotting assay identified proteins related to proliferation and apoptosis.Results:In NSCLC tissues,LINC00609 was expressed in low levels,while its high expression was associated with a higher survival rate.LINC00609 affected cell proliferation,apoptosis,cell cycle arrest,and expression of related proteins.Dual-luciferase reporter assay showed that LINC00609 binds specifically to miR-128-3p,and miR-128-3p binds to RND3.MiR-128-3p overexpression could neutralize the effects of LINC00609.A siRNA targeting RND3 could reverse the effect of the miR-128-3p inhibitor.Silencing RND3 resulted in a decrease in apoptosis rate and the number of cells in the S-phase and an increase in the number of cells in the G1-phase.Furthermore,phosphorylation levels of the AKT protein and mTOR protein,and Bcl2 expression,increased;however,the expression of RND3,Bax,and caspase3 decreased.Conclusions:LINC00609 regulated miR-128-3p/RND3 axis to modulate A549 cell proliferation,apoptosis,and cell cycle arrest.In the case of NSCLC,LINC00609 could be a potential target for therapy.展开更多
The performance of an iodine radio ion thruster with a 4 cm diameter(IRIT4)was studied experimentally in this paper.Regulation of the mass flow rates of the iodine propellant is achieved by using a temperature control...The performance of an iodine radio ion thruster with a 4 cm diameter(IRIT4)was studied experimentally in this paper.Regulation of the mass flow rates of the iodine propellant is achieved by using a temperature control method of the iodine reservoir.Performance of the thruster using iodine as propellants is obtained at different total thruster powers of 40.6–128.8 W,different grid voltages of 1000–1800 V and the iodine flow rate of 100μgs^(-1).Results show that thrust and specific impulse increase approximately linearly with the increasing total thruster power and the screen grid voltage.The thrust of 2.32 mN and the specific impulse of 2361 s are obtained at the nominal total thruster power of 95.8 W and the screen grid voltage of 1800 V.It is also indicated that performance of the iodine propellant is comparable to that of the xenon propellant;and a difference between them is that the iodine thrust is slightly higher than xenon when the total thruster power is more than 62 W.At the nominal 95.8 W total thruster power,the thrust values of them are 2.32 m N and 2.15 mN respectively,and the thrust-to-power ratios of them are 24.2 mN kW^(-1)and 23.5 mN kW^(-1),respectively.展开更多
A well-designed reflector surface with high beam pointing accuracy in electromagnetic performance is of practical significance to the space application of cable mesh reflector antennas. As for space requirements, cir-...A well-designed reflector surface with high beam pointing accuracy in electromagnetic performance is of practical significance to the space application of cable mesh reflector antennas. As for space requirements, cir- cular polarizations are widely used in spaceborne antennas, which usually lead to a beam shift for offset reflectors and influence the beam pointing accuracy. A two-step structural design procedure is proposed to overcome the beam squint phenomenon for high beam pointing accuracy design of circularly polarized offset cable mesh reflectors. A simple structural optimal design and an integrated structural electromagnetic optimization are combined to alleviate the beam squint effect of circular polarizations. It is imple- mented by cable pretension design and adjustment to shape the offset cable mesh surface. Besides, in order to increase the efficiency of integrated optimization, an update Broy- den-Fletcher-Goldfarb-Shanno (BFGS) Hessian matrix is employed in the optimization iteration with sequential quadratic programming. A circularly polarized offset cable mesh reflector is utilized to show the feasibility and effectiveness of the proposed procedure. A high beam pointing accuracy in order of 0.0001~ of electromagnetic performance is achieved.展开更多
Herein,we reported in situ synthesis of biomass-derived Ni/C catalyst by self-reduction with pomelo peel.Compared with the conventional method, which includes carbonization, activation, impregnation and reduction, the...Herein,we reported in situ synthesis of biomass-derived Ni/C catalyst by self-reduction with pomelo peel.Compared with the conventional method, which includes carbonization, activation, impregnation and reduction, the entire preparation process was simplified to two steps, which was more straightforward. This synthesis method was green as Ni/C can be prepared without any additional chemical and the self-reduction process was realized in N2, which can avoid using H2 thus averting some problems such as storage, transportation and safety of H2. Meanwhile, the size and dispersion of Ni particles can be controlled by changing carbonization temperature.The synthesis mechanism of Ni/C catalyst with selfreduction was investigated, which was mainly attributed to the carbon and reducing gas produced during the carbonization process.For the catalytic performance of GVL synthesis, a high yield (94.5%) can be obtained and it exhibited good stability up to 5 cycles without obvious loss of catalytic activity.展开更多
This paper reports the ignition performance of the iodine-fueled radio frequency(RF)ion thruster(IRIT)at different anode temperaturesT_(a0).The experimental results show that the anode temperature plays important role...This paper reports the ignition performance of the iodine-fueled radio frequency(RF)ion thruster(IRIT)at different anode temperaturesT_(a0).The experimental results show that the anode temperature plays important role on the ignition process of the IRIT.There were two characteristic temperatures related to the anode:the minimum ignition temperatureT_(i0)and the stable ignition temperatureT_(is),which were much lower than the pipeline temperature and the storage tank temperature.AtT_(a0)<T_(i0),it failed to discharge.WhenT_(i0)≤T_(a0)<T_(is),it was ignited with dramatical oscillations.AtT_(a0)≥T_(is),the discharge was stable in a large anode temperature range.The analysis showed that the different discharge phenomena at different anode temperatures were attributed to the change of iodine flow rate during the process of the iodine deposition-clogging and sublimation-clearing inside the thruster.The research helps improve the preheating design of the iodine-fueled electric thruster.展开更多
Ni-base catalysts are promising candidate for the hydrogenation of furfural(FAL) to high-value chemicals.However,slow intermediate desorption and low selectivity limit its implementation.Identifying the catalytic perf...Ni-base catalysts are promising candidate for the hydrogenation of furfural(FAL) to high-value chemicals.However,slow intermediate desorption and low selectivity limit its implementation.Identifying the catalytic performance of each active sites is vital to design hydrogenation catalyst,and tuning the geometrical sites at molecule level in PtNi could lead to the modification of electronic structure,and thus the selectity for the hydrogenation of FAL was modulated.Herein,PtNi hollow nanoframes(PtNi HNFs) with three dimensional(3 D) molecular accessibility were synthesized,EDX results suggested that Ni was evenly distributed inside of the hollow nanoframes,whereas Pt was relatively concentrated at the edges.DFT calculation demonstrated that PtNi significant decrease the desorption energy of the intermediates.This strategy could not only enhance the desorption of intermediates to improve the catalytic performance,but also transfer the adsorption mode of FAL on catalyst surface to selective hydrogenation of FAL to FOL or THFA.The PtNi HNFs catalyst afforded excellent catalytic performance for selective hydrogenation of a broad range of biomass-derived platform chemicals under mild conditions,especially of FAL to furfuryl alcohol(FOL),in quantitative FOL yields(99%) with a high TOF of 2.56 h^(-1).It is found that the superior performance of PtNi HNFs is attributed to its 3 D hierarchical structure and synergistic electronic effects between Pt and Ni.Besides,the kinetic study demonstrated that the activation energy for hydrogenation of FAL was as low as 54.95 kJ mol^(-1).展开更多
Identifying desirable genotypes with the best performance in diverse environments is a perpetual aim of plant breeding,and the interaction between genotype and environment(G×E)always plays a key role.This study w...Identifying desirable genotypes with the best performance in diverse environments is a perpetual aim of plant breeding,and the interaction between genotype and environment(G×E)always plays a key role.This study was conducted to elucidate the genetic behaviour of different hybrid combinations at various densities in diverse environments.According to a line×tester design,32 hybrid combinations were obtained from 16 inbred individuals crossed with two testers and planted at three locations at three density levels(45,000,67,500 and 90,000 plants ha-1)during 2014-2017.Genotype(G),environment(E)and the interaction of genotype and environment(G×E)significantly affected grain yield at different densities.Increasing planting density enhanced grain yield and improved the efficiency of germplasm screening,where the effect of location on grain yield at different densities was larger than that of year and the GCA was larger than the SCA.Finally,four inbred lines(KB102,KB081,KA105,and KB106)with a high GCA,environmental adaptability,and several combinations using them as parents have been approved in ShannXi Province and National of China.In conclusion,the evaluation of combining ability at multiple densities and locations can effectively screen inbred lines and improve breeding efficiency.展开更多
Inhibiting the side reactions while promoting hydrogenation are the main target for the production of functional anilines from nitroarenes;consequently,the preparation of an ideal catalyst to improve chemical selectiv...Inhibiting the side reactions while promoting hydrogenation are the main target for the production of functional anilines from nitroarenes;consequently,the preparation of an ideal catalyst to improve chemical selectivity is one of the hot issues.In this work,we provided an easy-to-prepare catalyst with Ndoped carbon layers,where the Fe_(x)O_(y)nanoparticles were encapsulated and distributed uniformly.The structural features of catalyst were characterized by several techniques,and the selected catalyst was next applied to the hydrogenation of nitrobenzene under varied conditions,involving temperature,holding period and H2 pressure.Subsequently,we conducted the synthesis of more than 16 substrates for the corresponding anilines with varied functional groups.The hydrogenation protocol to gram-scale synthesis as well as lifecycle performance were also demonstrated in the batch reactor,together with the explanation of its catalytic mechanisms.Overall,the present work provides an available preparation of simple but highly efficient catalysts for the production or aromatic amines,which will be benefit for the sustainable development of this field in near future.展开更多
The preparation of green and economical bio-aviation fuel is a priority for the sustainable development industry.In this study,Jatropha oil was used as a raw material to catalyze the conversion of raw material to avia...The preparation of green and economical bio-aviation fuel is a priority for the sustainable development industry.In this study,Jatropha oil was used as a raw material to catalyze the conversion of raw material to aviation kerosene fraction by photothermal coupling under the conditions of light and low temperature.The correlations among conversion rate,target alkane selectivity,composition distribution,and catalyst microstructure were investigated by X-ray diffraction(XRD),high-resolution transmission electron microscopy(HRTEM),nitrogen(N2)adsorption and desorption,X-ray fluorescence(XRF),ammoniatemperature programmed desorption(NH3-TPD),ultraviolet-visible spectrophotometry(UV-Vis),and other characterization.The correlation between conversion and target alkane selectivity and composition distribution and catalyst microstructure was investigated,and different modification methods and different molecular sieve materials were selected.The results showed that the molecular sieves modified with the solid dispersion method could retain the structural stability of titanium dioxide(TiO2)and molecular sieves to a great extent while slightly enhancing the pore capacity and pore size of the catalyst to make it easier to adsorb reactants;the introduction of active metal platinum(Pt)could reduce the forbidden bandwidth of the catalyst,increase the weak acid amount of the catalyst,improve the adsorption capacity of hydrogen(H2),and thus improve the catalytic ability,resulting in a suitable catalyst for this study:P-21.The photothermal catalytic reaction of Jatropha oil using P-21 catalyst obtained 97.21%conversion and 74.99%selectivity of the target alkanes under the optimal process parameters.The results of this study provide effective catalyst parameters for research in the field of clean energy.展开更多
基金funded by the Scientific and Technological Service Project of CNOOC Tianjin Branch“Research on Rock Mechanical Response Characteristics and Fracture Extension Mechanism of Metamorphic Reservoirs in the Southwest Ring of the Archaean Group in the Bozhong Sag,Bohai Bay Basin”.CCL2022TJX0NST1189.
文摘Hydraulic fracturing is a mature and effectivemethod for deep oil and gas production,which provides a foundation for deep oil and gas production.One of the key aspects of implementing hydraulic fracturing technology lies in understanding mechanics response characteristics of rocks in deep reservoirs under complex stress conditions.In this work,based on outcrop core samples,high-stress triaxial compression tests were designed to simulate the rock mechanics behavior of deep reservoirs in Bozhong Sag.Additionally,this study analyzes the deformation and damage law for rock under different stress conditions.Wherein,with a particular focus on combining energy dissipation theory to further understand damage law for deep reservoirs.The experimental results show that regardless of stress conditions,the process of deformation/failure of deep-seated reservoirs goes through five stages:Fracture compaction,newfracture formation,stable fracture expansion,unstable fracture expansion,and post-peak residual deformation.Under different stress conditions,the energy change laws of specimens are similar.The energy dissipation process of rocks corresponds closely to the trend of deformation-failure curve,then displays distinctive stage characteristics.Wherein,in stage of rock fracture compaction,the input energy curve is approximately coincident with the elastic strain energy curve,while the dissipation energy curve remains near zero.With the increase of strain,the growth rate of elastic strain energy increases gradually,but with the deformation entering the crack propagation stage,the growth rate of elastic strain energy slows down and the dissipation energy increases gradually.Finally,in the post-peak stage,rock fracture releases a lot of energy,which leads to the sharp decline of elastic strain energy curve.In addition,the introduction of damage variable D quantifies the analysis of the extent of failure for rocks.During the process of increasing strain,rock damage exhibits nonlinear growth with increasing stress.
基金funded by grants from the National Natural Science Foundation of China(No.52236010,51876210)the Fundamental Research Funds for the Central Universities(No.2242022R10058)。
文摘In this work,a“cyclopentanone-vanillin”strategy was proposed for the preparation of jet fuel range cycloalkanes from lignocellulose-derived ketones and lignin-derived aldehydes via aldol condensation and hydrodeoxygenation(HDO).Ethanolamine lactate ionic liquid(LAIL)exhibited excellent catalytic activity in the aldol condensation of cyclopentanone and vanillin.Desired mono-condensation and bicondensation products were obtained with yield of 95.2%at 100℃.It is found that the synergy effects between amino group of ethanolamine and hydroxyl group of lactic acid play a key role in the aldol condensation.The condensation products were converted into cycloalkanes by HDO over 5%Pd/Nb_(2)O_(5)catalyst.The density of the obtained HDO products is 0.89 g/cm^(3)and the freezing point is lower than-60℃.These results suggest that the resulted cycloalkanes can be used as additives to improve the density and low-temperature fluidity of the jet fuels.
基金financially supported by the National Natural Science Foundation of China (32072661)the National Key Research and Development Program of China(2021YFF1000500)。
文摘Acid soils occupy approximately 50% of potentially arable lands.Improving crop productivity in acid soils,therefore,will be crucial for ensuring food security and agricultural sustainability.High soil acidity often coexists with phosphorus(P) deficiency and aluminum(Al) toxicity,a combination that severely impedes crop growth and yield across wide areas.As roots explore soil for the nutrients and water required for plant growth and development,they also sense and respond to below-ground stresses.Within the terrestrial context of widespread P deficiency and Al toxicity pressures,plants,particularly roots,have evolved a variety of mechanisms for adapting to these stresses.As legumes,soybean(Glycine max) plants may acquire nitrogen(N) through symbiotic nitrogen fixation(SNF),an adaptation that can be useful for mitigating excessive N fertilizer use,either directly as leguminous crop participants in rotation and intercropping systems,or secondarily as green manure cover crops.In this review,we investigate legumes,especially soybean,for recent advances in our understanding of root-based mechanisms linked with root architecture modification,exudation and symbiosis,together with associated genetic and molecular strategies in adaptation to individual and/or interacting P and Al conditions in acid soils.We propose that breeding legume cultivars with superior nutrient efficiency and/or Al tolerance traits through genetic selection might become a potentially powerful strategy for producing crop varieties capable of maintaining or improving yields in more stressful soil conditions subjected to increasingly challenging environmental conditions.
基金the China Agriculture Research System(CARS-02-77)the Shaanxi Province Research and Development Project(2021LLRH-07)the Yangling Seed Industry Innovation Center Project(YLZY-YM-01).
文摘Superior inbred lines are central to maize breeding as sources of natural variation.Although many elite lines have been sequenced,less sequencing attention has been paid to newly developed lines.We constructed a genome assembly of the elite inbred line KA105,which has recently been developed by an arti-ficial breeding population named Shaan A and has shown desirable characteristics for breeding.Its pedigree showed genetic divergence from B73 and other lines in its pedigree.Comparison with the B73 reference genome revealed extensive structural variation,58 presence/absence variation(PAV)genes,and 1023 expanded gene families,some of which may be associated with disease resistance.A network-based integrative analysis of stress-induced transcriptomes identified 13 KA105-specific PAV genes,of which eight were induced by at least one kind of stress,participating in gene modules responding to stress such as drought and southern leaf blight disease.More than 200,000 gene pairs were differentially correlated between KA105 and B73 during kernel development.The KA105 reference genome and transcriptome atlas are a resource for further germplasm improvement and surveys of maize genomic variation and gene function.
基金supported by the Fundamental Research Funds for the Central Universities(No.2042021kf1038).
文摘Background:Long-chain non-coding RNA(lncRNA)LINC00609 is a potential tumor suppressor,but the mechanism of action in non-small cell lung cancer(NSCLC)is yet to be understood.Objectives:The effects of LINC00609 on A549 cell proliferation,apoptosis,and cell cycle arrest were investigated.Methods:The LINC00609 levels in NSCLC and normal tissues were analyzed by bioinformatics.Expressions of LINC00609,miR-128-3p,and Rho family GTPase 3(RND3)in NSCLC cells(A549)were determined by qRT-PCR.Bioinformatics analysis predicted target genes and dual-luciferase reporter assays to ensure that LINC00609 targeted miR-128-3p and miR-128-3p targeted RND3.The proliferation of cells was determined using EDU and CCK-8.Flow cytometry was used to evaluate cell apoptosis rate and cell cycle.The western blotting assay identified proteins related to proliferation and apoptosis.Results:In NSCLC tissues,LINC00609 was expressed in low levels,while its high expression was associated with a higher survival rate.LINC00609 affected cell proliferation,apoptosis,cell cycle arrest,and expression of related proteins.Dual-luciferase reporter assay showed that LINC00609 binds specifically to miR-128-3p,and miR-128-3p binds to RND3.MiR-128-3p overexpression could neutralize the effects of LINC00609.A siRNA targeting RND3 could reverse the effect of the miR-128-3p inhibitor.Silencing RND3 resulted in a decrease in apoptosis rate and the number of cells in the S-phase and an increase in the number of cells in the G1-phase.Furthermore,phosphorylation levels of the AKT protein and mTOR protein,and Bcl2 expression,increased;however,the expression of RND3,Bax,and caspase3 decreased.Conclusions:LINC00609 regulated miR-128-3p/RND3 axis to modulate A549 cell proliferation,apoptosis,and cell cycle arrest.In the case of NSCLC,LINC00609 could be a potential target for therapy.
基金supported by the National Natural Science Foundation of China (21922815, 51802325)the Natural Science Foundation of Shanxi Province (201901D211585)+2 种基金the Scientific and Technological Key Project of Shanxi Province (20191102003)the Patent Promotion and Implementation Project of Shanxi Province (20200716)the Key Research and Development (R&D) Projects of Shanxi Province (201903D121007)。
基金financial support from National Natural Science Foundation of China(No.11805265)Key Laboratory of Micro-Satellites,Chinese Academy of Sciences(No.KFKT201903)。
文摘The performance of an iodine radio ion thruster with a 4 cm diameter(IRIT4)was studied experimentally in this paper.Regulation of the mass flow rates of the iodine propellant is achieved by using a temperature control method of the iodine reservoir.Performance of the thruster using iodine as propellants is obtained at different total thruster powers of 40.6–128.8 W,different grid voltages of 1000–1800 V and the iodine flow rate of 100μgs^(-1).Results show that thrust and specific impulse increase approximately linearly with the increasing total thruster power and the screen grid voltage.The thrust of 2.32 mN and the specific impulse of 2361 s are obtained at the nominal total thruster power of 95.8 W and the screen grid voltage of 1800 V.It is also indicated that performance of the iodine propellant is comparable to that of the xenon propellant;and a difference between them is that the iodine thrust is slightly higher than xenon when the total thruster power is more than 62 W.At the nominal 95.8 W total thruster power,the thrust values of them are 2.32 m N and 2.15 mN respectively,and the thrust-to-power ratios of them are 24.2 mN kW^(-1)and 23.5 mN kW^(-1),respectively.
文摘A well-designed reflector surface with high beam pointing accuracy in electromagnetic performance is of practical significance to the space application of cable mesh reflector antennas. As for space requirements, cir- cular polarizations are widely used in spaceborne antennas, which usually lead to a beam shift for offset reflectors and influence the beam pointing accuracy. A two-step structural design procedure is proposed to overcome the beam squint phenomenon for high beam pointing accuracy design of circularly polarized offset cable mesh reflectors. A simple structural optimal design and an integrated structural electromagnetic optimization are combined to alleviate the beam squint effect of circular polarizations. It is imple- mented by cable pretension design and adjustment to shape the offset cable mesh surface. Besides, in order to increase the efficiency of integrated optimization, an update Broy- den-Fletcher-Goldfarb-Shanno (BFGS) Hessian matrix is employed in the optimization iteration with sequential quadratic programming. A circularly polarized offset cable mesh reflector is utilized to show the feasibility and effectiveness of the proposed procedure. A high beam pointing accuracy in order of 0.0001~ of electromagnetic performance is achieved.
基金funded by the National Key R&D Program of China (2018YFB1501504)the National Natural Science Foundation of China (Nos. 51776206 and 21878290)+1 种基金the Natural Science Foundation of Guangdong province (2017A030313073)CAS Pioneer Hundred Talents Program
文摘Herein,we reported in situ synthesis of biomass-derived Ni/C catalyst by self-reduction with pomelo peel.Compared with the conventional method, which includes carbonization, activation, impregnation and reduction, the entire preparation process was simplified to two steps, which was more straightforward. This synthesis method was green as Ni/C can be prepared without any additional chemical and the self-reduction process was realized in N2, which can avoid using H2 thus averting some problems such as storage, transportation and safety of H2. Meanwhile, the size and dispersion of Ni particles can be controlled by changing carbonization temperature.The synthesis mechanism of Ni/C catalyst with selfreduction was investigated, which was mainly attributed to the carbon and reducing gas produced during the carbonization process.For the catalytic performance of GVL synthesis, a high yield (94.5%) can be obtained and it exhibited good stability up to 5 cycles without obvious loss of catalytic activity.
基金financial support from National Natural Science Foundation of China(No.11805265)Key Laboratory of Micro-Satellites,Chinese Academy of Sciences(No.KFKT201903)is gratefully acknowledged。
文摘This paper reports the ignition performance of the iodine-fueled radio frequency(RF)ion thruster(IRIT)at different anode temperaturesT_(a0).The experimental results show that the anode temperature plays important role on the ignition process of the IRIT.There were two characteristic temperatures related to the anode:the minimum ignition temperatureT_(i0)and the stable ignition temperatureT_(is),which were much lower than the pipeline temperature and the storage tank temperature.AtT_(a0)<T_(i0),it failed to discharge.WhenT_(i0)≤T_(a0)<T_(is),it was ignited with dramatical oscillations.AtT_(a0)≥T_(is),the discharge was stable in a large anode temperature range.The analysis showed that the different discharge phenomena at different anode temperatures were attributed to the change of iodine flow rate during the process of the iodine deposition-clogging and sublimation-clearing inside the thruster.The research helps improve the preheating design of the iodine-fueled electric thruster.
基金financially supported by the National Key R&D Program of China (No. 2019YFD1100601)the National Key R & D Program of China (2018YFB1501500)+2 种基金the National Natural Science Foundation of China (Nos. 51776206 and 51536009)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program (2017BT01N092)the ‘‘Transformational Technologies for Clean Energy and Demonstration”, the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA21060102)。
文摘Ni-base catalysts are promising candidate for the hydrogenation of furfural(FAL) to high-value chemicals.However,slow intermediate desorption and low selectivity limit its implementation.Identifying the catalytic performance of each active sites is vital to design hydrogenation catalyst,and tuning the geometrical sites at molecule level in PtNi could lead to the modification of electronic structure,and thus the selectity for the hydrogenation of FAL was modulated.Herein,PtNi hollow nanoframes(PtNi HNFs) with three dimensional(3 D) molecular accessibility were synthesized,EDX results suggested that Ni was evenly distributed inside of the hollow nanoframes,whereas Pt was relatively concentrated at the edges.DFT calculation demonstrated that PtNi significant decrease the desorption energy of the intermediates.This strategy could not only enhance the desorption of intermediates to improve the catalytic performance,but also transfer the adsorption mode of FAL on catalyst surface to selective hydrogenation of FAL to FOL or THFA.The PtNi HNFs catalyst afforded excellent catalytic performance for selective hydrogenation of a broad range of biomass-derived platform chemicals under mild conditions,especially of FAL to furfuryl alcohol(FOL),in quantitative FOL yields(99%) with a high TOF of 2.56 h^(-1).It is found that the superior performance of PtNi HNFs is attributed to its 3 D hierarchical structure and synergistic electronic effects between Pt and Ni.Besides,the kinetic study demonstrated that the activation energy for hydrogenation of FAL was as low as 54.95 kJ mol^(-1).
基金supported by the China Agriculture Research System(CARS-02),Key Research and Development Program of Shaanxi Province(2021LLRH-07)the Seed Industry Innovation of Yangling(Ylzy-ym-01).
文摘Identifying desirable genotypes with the best performance in diverse environments is a perpetual aim of plant breeding,and the interaction between genotype and environment(G×E)always plays a key role.This study was conducted to elucidate the genetic behaviour of different hybrid combinations at various densities in diverse environments.According to a line×tester design,32 hybrid combinations were obtained from 16 inbred individuals crossed with two testers and planted at three locations at three density levels(45,000,67,500 and 90,000 plants ha-1)during 2014-2017.Genotype(G),environment(E)and the interaction of genotype and environment(G×E)significantly affected grain yield at different densities.Increasing planting density enhanced grain yield and improved the efficiency of germplasm screening,where the effect of location on grain yield at different densities was larger than that of year and the GCA was larger than the SCA.Finally,four inbred lines(KB102,KB081,KA105,and KB106)with a high GCA,environmental adaptability,and several combinations using them as parents have been approved in ShannXi Province and National of China.In conclusion,the evaluation of combining ability at multiple densities and locations can effectively screen inbred lines and improve breeding efficiency.
基金supported financially by the National Natural Science Foundation of China(Nos.52236010,51876209,51876210 and 51906247)the Fundamental Research Funds for the Central Universities(No.2242022R10058)。
文摘Inhibiting the side reactions while promoting hydrogenation are the main target for the production of functional anilines from nitroarenes;consequently,the preparation of an ideal catalyst to improve chemical selectivity is one of the hot issues.In this work,we provided an easy-to-prepare catalyst with Ndoped carbon layers,where the Fe_(x)O_(y)nanoparticles were encapsulated and distributed uniformly.The structural features of catalyst were characterized by several techniques,and the selected catalyst was next applied to the hydrogenation of nitrobenzene under varied conditions,involving temperature,holding period and H2 pressure.Subsequently,we conducted the synthesis of more than 16 substrates for the corresponding anilines with varied functional groups.The hydrogenation protocol to gram-scale synthesis as well as lifecycle performance were also demonstrated in the batch reactor,together with the explanation of its catalytic mechanisms.Overall,the present work provides an available preparation of simple but highly efficient catalysts for the production or aromatic amines,which will be benefit for the sustainable development of this field in near future.
基金supported by the National Natural Science Foundation of China(Grant No.21868014)a Key Project of the Yunnan Fundamental Research Program(Study on Design of Novel Catalyst and Catalytic Process for Preparation of Bioaviation Kerosene from Vegetable Oils Based on Photo-thermal Catalytic Technology),2021 Low-carbon Development Guide Project of Yunnan Province,China(No.135),Key S&T Project of China Tobacco Yunnan Industrial Co.,Ltd.,(Grant No.2022GY03)+4 种基金Yunnan Academician and Expert Workstation(Grant No.202205AF150024)Yunnan International S&T Cooperation Program,China(Grant No.202003AF140001)Yunnan S&T Talents and Platform Program(Grant No.202105AC160058)Kunming International S&T Cooperation Base,China(Grant No.GHJD-2020026)Scientific research project of Yunnan Environmental Science Society,China(Grant No.XHKYKT006).
文摘The preparation of green and economical bio-aviation fuel is a priority for the sustainable development industry.In this study,Jatropha oil was used as a raw material to catalyze the conversion of raw material to aviation kerosene fraction by photothermal coupling under the conditions of light and low temperature.The correlations among conversion rate,target alkane selectivity,composition distribution,and catalyst microstructure were investigated by X-ray diffraction(XRD),high-resolution transmission electron microscopy(HRTEM),nitrogen(N2)adsorption and desorption,X-ray fluorescence(XRF),ammoniatemperature programmed desorption(NH3-TPD),ultraviolet-visible spectrophotometry(UV-Vis),and other characterization.The correlation between conversion and target alkane selectivity and composition distribution and catalyst microstructure was investigated,and different modification methods and different molecular sieve materials were selected.The results showed that the molecular sieves modified with the solid dispersion method could retain the structural stability of titanium dioxide(TiO2)and molecular sieves to a great extent while slightly enhancing the pore capacity and pore size of the catalyst to make it easier to adsorb reactants;the introduction of active metal platinum(Pt)could reduce the forbidden bandwidth of the catalyst,increase the weak acid amount of the catalyst,improve the adsorption capacity of hydrogen(H2),and thus improve the catalytic ability,resulting in a suitable catalyst for this study:P-21.The photothermal catalytic reaction of Jatropha oil using P-21 catalyst obtained 97.21%conversion and 74.99%selectivity of the target alkanes under the optimal process parameters.The results of this study provide effective catalyst parameters for research in the field of clean energy.