CSIRO has had a long-term research effort in superconductivity, in particular, since the discovery of HTS which promised big prospects. Significant progress has been made in research and development of HTS electronic ...CSIRO has had a long-term research effort in superconductivity, in particular, since the discovery of HTS which promised big prospects. Significant progress has been made in research and development of HTS electronic devices and systems for practical applications such as mineral and exploration as well as some niche applications in emerging science and technology areas. This article presents an overview of the CSIRO research activities in HTS supercon- ducting electronics since 1987, outlining the HTS junction and device technology as well as various application systems developed by the group.展开更多
Background:Tandem gene repeats naturally occur as important genomic features and determine many traits in living organisms,like human diseases and microbial productivities of target bioproducts.Methods:Here,we develop...Background:Tandem gene repeats naturally occur as important genomic features and determine many traits in living organisms,like human diseases and microbial productivities of target bioproducts.Methods:Here,we developed a bacterial type-II toxin-antitoxin-mediated method to manipulate genomic integration of tandem gene repeats in Saccharomyces cerevisiae and further visualised the evolutionary trajectories of gene repeats.We designed a tri-vector system to introduce toxin-antitoxin-driven gene amplification modules.Results:This system delivered multi-copy gene integration in the form of tandem gene repeats spontaneously and independently from toxin-antitoxin-mediated selection.Inducing the toxin(RelE)expressing via a copper(II)-inducible CUP1 promoter successfully drove the in-situ gene amplification of the antitoxin(RelB)module,resulting in~40 copies of a green fluorescence reporter gene per copy of genome.Copy-number changes,copy-number increase and copy-number decrease,and stable maintenance were visualised using the green fluorescence protein and blue chromoprotein AeBlue as reporters.Copy-number increases happened spontaneously and independent on a selection pressure.Increased copy number was quickly enriched through toxin-antitoxin-mediated selection.Conclusion:In summary,the bacterial toxin-antitoxin systems provide a flexible mechanism to manipulate gene copy number in eukaryotic cells and can be exploited for synthetic biology and metabolic engineering applications.展开更多
Accurate prediction of flood events is important for flood control and risk management.Machine learning techniques contributed greatly to advances in flood predictions,and existing studies mainly focused on predicting...Accurate prediction of flood events is important for flood control and risk management.Machine learning techniques contributed greatly to advances in flood predictions,and existing studies mainly focused on predicting flood resource variables using single or hybrid machine learning techniques.However,class-based flood predictions have rarely been investigated,which can aid in quickly diagnosing comprehensive flood characteristics and proposing targeted management strategies.This study proposed a prediction approach of flood regime metrics and event classes coupling machine learning algorithms with clustering-deduced membership degrees.Five algorithms were adopted for this exploration.Results showed that the class membership degrees accurately determined event classes with class hit rates up to 100%,compared with the four classes clustered from nine regime metrics.The nonlinear algorithms(Multiple Linear Regression,Random Forest,and least squares-Support Vector Machine)outperformed the linear techniques(Multiple Linear Regression and Stepwise Regression)in predicting flood regime metrics.The proposed approach well predicted flood event classes with average class hit rates of 66.0%-85.4%and 47.2%-76.0%in calibration and validation periods,respectively,particularly for the slow and late flood events.The predictive capability of the proposed prediction approach for flood regime metrics and classes was considerably stronger than that of hydrological modeling approach.展开更多
This past year, 2024, is on track to be the warmest year, joining 2023 as the two hottest years on record. With the exceptional heat, weather and climate extremes were common across the world. In particular, 2024 has ...This past year, 2024, is on track to be the warmest year, joining 2023 as the two hottest years on record. With the exceptional heat, weather and climate extremes were common across the world. In particular, 2024 has seen a remarkable run of extreme precipitation events and resulting impacts. Here, we provide an overview of the most notable extreme events of the year, including extreme precipitation and floods, tropical cyclones, and droughts. The characteristics and impacts of these extreme events are summarized, followed by discussion on the physical drivers and the role of global warming.Finally, we also discuss the future prospects in extreme event studies, including impact-based perspectives, challenges in attribution of precipitation extremes, and the existing gap to minimize impacts from climate extremes.展开更多
The insect order Thysanoptera is used as an indicator of the vulnerability to foreign insect invasions of New Caledonian ecosystems—both the unique natural systems, and the agricultural and horticultural systems on w...The insect order Thysanoptera is used as an indicator of the vulnerability to foreign insect invasions of New Caledonian ecosystems—both the unique natural systems, and the agricultural and horticultural systems on which the economy is dependent. A total of 103 species in 67 genera of Thysanoptera are here listed from New Caledonia, in contrast to the 68 species in 44 genera that were recorded 23 years ago. Of the 103 species, 22 are not known from anywhere else in the world. Thus, up to 80% of these insect species have arrived in New Caledonia from other countries, with a very high proportion likely to have been introduced through modern trading patterns, despite vigorous efforts by quarantine services.展开更多
In deep underground engineering construction,the dominant rock failure mode,whether by tension or shear,influences the engineering instability.Therefore,the critical triggering conditions that induce shear or tensile ...In deep underground engineering construction,the dominant rock failure mode,whether by tension or shear,influences the engineering instability.Therefore,the critical triggering conditions that induce shear or tensile fractures in rocks urgently need further investigation.This paper designs direct shear tests on intact limestone under different normal stress conditions,using binarization methods supplemented by scanning electron microscopy to explore the two-dimensional fracture damage characteristics of limestone joint surfaces.Based on the three-dimensional morphological characteristics of limestone joint surfaces,a method for automatically identifying the three-dimensional curvature of rock joint surfaces is proposed,quantifying the changes in curvature distribution under different normal stresses.Further analysis focused on the proportion of shear damage and high-curvature areas on the upper and lower joint surfaces of limestone.The study examined changes in the cumulative energy of pre-peak acoustic emission and damage under varying effective normal stress-to-shear stress ratios.These results were used to identify and validate the critical threshold range for inducing shear fractures in limestone.The conclusions indicate that the proportion of shear damage area of limestone joint surfaces is positively correlated with effective normal stress.The proportion of high curvature of limestone joint surfaces decreases with increasing normal stress.Both the rapid growth stage of shear damage area and the rapid descent stage of high curvature proportion occur in the effective normal stress to shear stress ratio range of[1.4,1.6].The cumulative energy of pre-peak acoustic emission and damage under different effective normal stress to shear stress ratios increase sharply around the ratio of 1.6,further verifying that the effective normal stress to shear stress ratio range of[1.4,1.6]is the critical threshold range for inducing shear fractures in limestone.展开更多
Achieving a sustainable cropping system requires the efficient use of resources,particularly nitrogen(N).Nitrogen fertiliser is applied in most irrigated cotton fields to maximise yield potential,but plant fertiliser ...Achieving a sustainable cropping system requires the efficient use of resources,particularly nitrogen(N).Nitrogen fertiliser is applied in most irrigated cotton fields to maximise yield potential,but plant fertiliser recovery can be low.Identifying the crucial pathways of fertiliser remobilisation internally within cotton plants will lead to greater awareness of the plants’ability to match the N demands of the developing fruiting matter.This study investigated the fate of N fertiliser when applied to cotton at various dates,with the goal to improve N fertiliser recovery in a modern transgenic cotton cultivar.15N-labelled urea(10 atom%)was applied at multiple times and harvested at four key cotton growth stages(first square,early bolls,cut-out and maturity).Remobilised N was determined as the difference in the proportion of N fertiliser in individual plant components against the fertiliser utilised by the whole plant.The application of fertiliser N at first square resulted in 23%greater fertiliser N recovery at plant maturity compared to fertiliser N applied 100%pre-plant(P<0.001).The improvement was in-part due to higher N derived from the fertiliser(Ndff%)in the cotton seed(3%).Conversely,the Ndff%was higher in the stem(4%)and petioles(1%)when the fertiliser was applied pre-plant.In total,73%of plant N was remobilised to another plant organ,predominantly the seed(67%).Applying N fertiliser post-planting improved N recovery and lint yield compared to applying all fertiliser pre-plant.展开更多
Our understanding of grain-level bursts of plasticity in polycrystals remains limited by current techniques.By employing a modified Synchrotron transmission X-ray Laue diffraction method(beam size larger than the grai...Our understanding of grain-level bursts of plasticity in polycrystals remains limited by current techniques.By employing a modified Synchrotron transmission X-ray Laue diffraction method(beam size larger than the grain size),we tracked grain rotations for the first 1%of tensile strain,in 4400 time steps.We indexed 33 grains and quantified the magnitude and frequency of intermittent bursts of grain rotation.We interpret these events in terms of bursts of plastic deformation.The events are highly coordinated amongst nearby grains,and their frequency and magnitude,as well as the number of grains participating,peaked at around the onset of full plasticity.At this point,7 out of the 10 indexed grains with orientations favorable for twinning showed significant drops in diffracted intensity(a mean value of 8%),due to twin induced re-orientation.For other orientations,20 out of 23 grains displayed bursts attributable to lattice dislocation glide(interpreted in terms of basal and prismatic <α> slip).The mean value of the magnitude of these bursts is∼0.08°,implying accumulated shear strains of the order of 3×10^(-3).These bursts,in many cases,were due to the activation of more than a single slip/twin system within the grain,and co-ordination amongst neighboring grains also involved collaboration between slip and twinning events.展开更多
Pyrrhotite naturally occurs in various superstructures including magnetic(4C)and non-magnetic(5C,6C)types,each with distinct physicochemical properties and flotation behaviors.Challenges in accurately identifying and ...Pyrrhotite naturally occurs in various superstructures including magnetic(4C)and non-magnetic(5C,6C)types,each with distinct physicochemical properties and flotation behaviors.Challenges in accurately identifying and quantifying these superstructures hinder the optimization of pyrrhotite depression in flotation processes.To address this critical issue,synchrotron X-ray powder diffraction(S-XRPD)with Rietveld refinement was employed to quantify the distribution of superstructures in the feed and flotation concentrates of a copper–gold ore.To elucidate the mechanisms influencing depression,density functional theory(DFT)calculations were conducted to explore the electronic structures and surface reactivity of the pyrrhotite superstructures toward the adsorption of water,oxygen and hydroxyl ions(OH-)as dominant species present in the flotation process.S-XRPD analysis revealed that flotation recovery rates of pyrrhotite followed the order of 4C<6C<5C.DFT calculations indicated that the Fe 3d and S 3p orbital band centers exhibited a similar trend relative to the Fermi level with 4C being the closest.The Fe3d band center suggested that the 4C structure possessed a more reactive surface toward the oxygen reduction reaction,promoting the formation of hydrophilic Fe-OH sites.The S 3p band center order also implied that xanthate on the non-magnetic 5C and 6C surfaces could oxidize to dixanthogen,increasing hydrophobicity and floatability,while 4C formed less hydrophobic metal-xanthate complexes.Adsorption energy and charge transfer analyses of water,hydroxyl ions and molecular oxygen further supported the high reactivity and hydrophilic nature of 4C pyrrhotite.The strong bonding with hydroxyl ions indicated enhanced surface passivation by hydrophilic Fe–OOH complexes,aligning with the experimentally observed flotation order(4C<6C<5C).These findings provide a compelling correlation between experimental flotation results and electronic structure calculations,delivering crucial insights for optimizing flotation processes and improving pyrrhotite depression.This breakthrough opens up new opportunities to enhance the efficiency of flotation processes in the mining industry.展开更多
Understanding dynamic visualization of mining-induced stress is of great significance to disaster prevention and control in coal mining activities.In this study,three theoretical models,including linear,polynomial,and...Understanding dynamic visualization of mining-induced stress is of great significance to disaster prevention and control in coal mining activities.In this study,three theoretical models,including linear,polynomial,and exponential models,are proposed to inverse the mining-induced stress through the acquisition and analysis of hydraulic support stress and micro-seismicity in the coal mining face.The distribution of mining-induced stress in the coal seam are graphed by fitting two key stress parameters including hydraulic support stress and peak stress,and two key zones including goaf zone and in situ stress zone.These key stress parameters and zones are defined based on the critical nodes of the model curve.According to the geological background of Mataihao coal mine in Erdos,Inner Mongolia Autonomous Region,China,the contours of mining-induced stress are graphed through the stress calculation of these three inversion theoretical models.The multi-monitoring data of micro-seismicity,drilling chips,advanced borehole stress and bolts axial force are used to verify the key stress parameters and zones of the theoretical models.It shows that the monitoring data are in good agreement with the distribution of inversed results.It should be emphasized that,if the fault structure exists around the mining face,the mining-induced stress decreases obviously when the mining face is passing through the faults,and the location of the peak stress will be closer to the mining face.The results in this study could provide methods for early prevention of extreme mining-induced stress and disaster control in the mining activities.展开更多
CO_(2)injection in shale oil reservoirs has emerged as a promising technique for simultaneously achieving CO_(2)geological storage and enhancing shale oil recovery.This study investigates the potential of CO_(2)inject...CO_(2)injection in shale oil reservoirs has emerged as a promising technique for simultaneously achieving CO_(2)geological storage and enhancing shale oil recovery.This study investigates the potential of CO_(2)injection into shale oil reservoirs with natural fractures for carbon storage and enhanced oil recovery through a combination of experimental and numerical simulations.It focuses on the synergistic effects on carbon storage capacity and oil recovery efficiency.A series of CO_(2)injection experiments using online NMR T_(2)and stratified T_(2)technology were conducted to validate the feasibility of carbon storage and oil recovery in shale oil reservoirs.The shale samples consist of three distinct pore space systems:kerogen,inorganic matrix,and shale bedding fractures.A coupled multiscale-multiphase simulation model was developed to facilitate a comprehensive analysis of the underlying mechanisms.In the model,kerogen,inorganic matrix,and shale bedding fractures are defined as triple-continuum media.The model integrates the mechanisms of molecular diffusion,adsorption,and viscous flow to accurately represent the mass transport processes during CO_(2)injection in shale oil reservoirs.Within this framework,a series of mass transport partial differential equations were derived to describe the CO_(2)injection process.The finite element method was used to numerically solve these equations,and the proposed model was validated against experimental results.Sensitivity analyses yielded the following results:(1)The shale bedding fractures are not only key reservoir spaces for shale oil but also the key mass transfer channels for shale oil and CO_(2)during CO_(2)injection.Increasing the permeability of the shale bedding fractures can significantly improve oil recovery efficiency and CO_(2)adsorption amount.(2)The kerogen content and organic porosity have a significant impact on CO_(2)adsorption amount and shale oil recovery factor,respectively.(3)High production pressure is essential for maximizing carbon storage capacity.Simultaneously,increasing injection pressure can effectively enhance carbon storage and shale oil recovery.展开更多
We present a wideband polarization analysis of the mode-changing pulsar PSR J1938+2213 using the ultra-wideband low-frequency receiver on Murriyang,the Parkes 64 m radio telescope.Polarization profiles for both the bu...We present a wideband polarization analysis of the mode-changing pulsar PSR J1938+2213 using the ultra-wideband low-frequency receiver on Murriyang,the Parkes 64 m radio telescope.Polarization profiles for both the burst and weak emission modes are obtained.We find that the pulse widths of the two modes exhibit distinct frequency dependencies:the pulse width increases with frequency in the burst mode,but decreases in the weak mode.The linear and circular polarization fractions also show different trends with frequency between the two modes.Our spectral analysis shows that both modes follow power-law spectra,but with differing spectral indices.展开更多
Deep geothermal extraction processes expose rock masses to frequent and significant temperature fluctuations. Developing a comprehensive understanding of the shear fracture mechanisms and crack propagation behaviors i...Deep geothermal extraction processes expose rock masses to frequent and significant temperature fluctuations. Developing a comprehensive understanding of the shear fracture mechanisms and crack propagation behaviors in rocks under the influence of cyclic heating is imperative for optimizing geothermal energy extraction. This study encompasses several critical aspects under cyclic heating conditions, including the assessment of stress distribution states, the characterization of two-dimensional fracture paths, the quantitative analysis of three-dimensional damage characteristics on fracture surfaces, and the determination of the fractal dimension of debris generated after the failure of granite. The test results demonstrate that cyclic heating has a pronounced adverse effect on the physical and mechanical properties of granite. Consequently, stress tends to develop and propagate in a direction perpendicular to the two-dimensional fracture path. This leads to an increase in the extent of tensile damage on the fracture surface and accelerates the overall rock failure process. This increases the number of small-sized debris, raises the fractal dimension, and enhances the rock’s rupture degree. In practical enhanced geothermal energy extraction, the real-time monitoring of fracture propagation within the reservoir rock mass is achieved through the analysis of rock debris generated during the staged fracturing process.展开更多
We present the first search for pulsed CH maser emission potentially stimulated by PSR J1644-4559,conducted using the ultra-wide-bandwidth low-frequency receiver on Murriyang,CSIRO's Parkes Radio Telescope.Observa...We present the first search for pulsed CH maser emission potentially stimulated by PSR J1644-4559,conducted using the ultra-wide-bandwidth low-frequency receiver on Murriyang,CSIRO's Parkes Radio Telescope.Observations targeted three CHΛ-doublet transitions at 3264,3335,and 3349 MHz,with a variability timescale of78 ms.We detected ten CH emission features at 3335 and 3349 MHz,and seven features at 3264 MHz,during both pulsar-ON and pulsar-OFF phases.The observed velocities align with the OH emission and absorption reported by a previous study,suggesting a close spatial association between CH and OH molecules.The derived column densities for CH clouds within the Parkes beam range from 0.05 to 9.8×10^(13)cm^(-2),indicating that these clouds are likely in diffuse and translucent states.Upper limits for CH column densities within the pulsar beam ranged from 0.3 to 9.8×10^(13)cm^(-2).Comparison of these column densities suggests that CH clouds may exhibit clumpiness and substructure.No significant stimulated emission feature was detected in the optical depth spectra.Additionally,as part of our search for pulsed stimulated emission,we investigated the potential CH absorption of the pulsar signal and found none,in agreement with astrophysical expectations.The upper limits for the potential maser amplification factors towards PSR J1644-4559 at 3264,3335,and 3349 MHz are 1.014,1.009,and 1.009,respectively.This study demonstrates the feasibility of detecting pulsed CH maser emission in the interstellar medium stimulated by pulsar photons.展开更多
文摘CSIRO has had a long-term research effort in superconductivity, in particular, since the discovery of HTS which promised big prospects. Significant progress has been made in research and development of HTS electronic devices and systems for practical applications such as mineral and exploration as well as some niche applications in emerging science and technology areas. This article presents an overview of the CSIRO research activities in HTS supercon- ducting electronics since 1987, outlining the HTS junction and device technology as well as various application systems developed by the group.
基金supported partially by the Australian Government through the Australian Research Council Centres of Excellence funding scheme(project CE200100029)。
文摘Background:Tandem gene repeats naturally occur as important genomic features and determine many traits in living organisms,like human diseases and microbial productivities of target bioproducts.Methods:Here,we developed a bacterial type-II toxin-antitoxin-mediated method to manipulate genomic integration of tandem gene repeats in Saccharomyces cerevisiae and further visualised the evolutionary trajectories of gene repeats.We designed a tri-vector system to introduce toxin-antitoxin-driven gene amplification modules.Results:This system delivered multi-copy gene integration in the form of tandem gene repeats spontaneously and independently from toxin-antitoxin-mediated selection.Inducing the toxin(RelE)expressing via a copper(II)-inducible CUP1 promoter successfully drove the in-situ gene amplification of the antitoxin(RelB)module,resulting in~40 copies of a green fluorescence reporter gene per copy of genome.Copy-number changes,copy-number increase and copy-number decrease,and stable maintenance were visualised using the green fluorescence protein and blue chromoprotein AeBlue as reporters.Copy-number increases happened spontaneously and independent on a selection pressure.Increased copy number was quickly enriched through toxin-antitoxin-mediated selection.Conclusion:In summary,the bacterial toxin-antitoxin systems provide a flexible mechanism to manipulate gene copy number in eukaryotic cells and can be exploited for synthetic biology and metabolic engineering applications.
基金National Key Research and Development Program of China,No.2023YFC3006704National Natural Science Foundation of China,No.42171047CAS-CSIRO Partnership Joint Project of 2024,No.177GJHZ2023097MI。
文摘Accurate prediction of flood events is important for flood control and risk management.Machine learning techniques contributed greatly to advances in flood predictions,and existing studies mainly focused on predicting flood resource variables using single or hybrid machine learning techniques.However,class-based flood predictions have rarely been investigated,which can aid in quickly diagnosing comprehensive flood characteristics and proposing targeted management strategies.This study proposed a prediction approach of flood regime metrics and event classes coupling machine learning algorithms with clustering-deduced membership degrees.Five algorithms were adopted for this exploration.Results showed that the class membership degrees accurately determined event classes with class hit rates up to 100%,compared with the four classes clustered from nine regime metrics.The nonlinear algorithms(Multiple Linear Regression,Random Forest,and least squares-Support Vector Machine)outperformed the linear techniques(Multiple Linear Regression and Stepwise Regression)in predicting flood regime metrics.The proposed approach well predicted flood event classes with average class hit rates of 66.0%-85.4%and 47.2%-76.0%in calibration and validation periods,respectively,particularly for the slow and late flood events.The predictive capability of the proposed prediction approach for flood regime metrics and classes was considerably stronger than that of hydrological modeling approach.
基金jointly supported by the National Natural Science Foundation of China (Grant Nos.42422502 and 42275038)the China Meteorological Administration Climate Change Special Program (Grant No.QBZ202306)funded by the Met Office Climate Science for Service Partnership (CSSP) China project under the International Science Partnerships Fund (ISPF)。
文摘This past year, 2024, is on track to be the warmest year, joining 2023 as the two hottest years on record. With the exceptional heat, weather and climate extremes were common across the world. In particular, 2024 has seen a remarkable run of extreme precipitation events and resulting impacts. Here, we provide an overview of the most notable extreme events of the year, including extreme precipitation and floods, tropical cyclones, and droughts. The characteristics and impacts of these extreme events are summarized, followed by discussion on the physical drivers and the role of global warming.Finally, we also discuss the future prospects in extreme event studies, including impact-based perspectives, challenges in attribution of precipitation extremes, and the existing gap to minimize impacts from climate extremes.
文摘The insect order Thysanoptera is used as an indicator of the vulnerability to foreign insect invasions of New Caledonian ecosystems—both the unique natural systems, and the agricultural and horticultural systems on which the economy is dependent. A total of 103 species in 67 genera of Thysanoptera are here listed from New Caledonia, in contrast to the 68 species in 44 genera that were recorded 23 years ago. Of the 103 species, 22 are not known from anywhere else in the world. Thus, up to 80% of these insect species have arrived in New Caledonia from other countries, with a very high proportion likely to have been introduced through modern trading patterns, despite vigorous efforts by quarantine services.
基金Projects(52004147,51974173)supported by the National Natural Science Foundation of ChinaProject(GJNY-20-113-19)supported by the Open Fund of State Key Laboratory of Water Resource Protection and Utilization in Coal Mining,China。
文摘In deep underground engineering construction,the dominant rock failure mode,whether by tension or shear,influences the engineering instability.Therefore,the critical triggering conditions that induce shear or tensile fractures in rocks urgently need further investigation.This paper designs direct shear tests on intact limestone under different normal stress conditions,using binarization methods supplemented by scanning electron microscopy to explore the two-dimensional fracture damage characteristics of limestone joint surfaces.Based on the three-dimensional morphological characteristics of limestone joint surfaces,a method for automatically identifying the three-dimensional curvature of rock joint surfaces is proposed,quantifying the changes in curvature distribution under different normal stresses.Further analysis focused on the proportion of shear damage and high-curvature areas on the upper and lower joint surfaces of limestone.The study examined changes in the cumulative energy of pre-peak acoustic emission and damage under varying effective normal stress-to-shear stress ratios.These results were used to identify and validate the critical threshold range for inducing shear fractures in limestone.The conclusions indicate that the proportion of shear damage area of limestone joint surfaces is positively correlated with effective normal stress.The proportion of high curvature of limestone joint surfaces decreases with increasing normal stress.Both the rapid growth stage of shear damage area and the rapid descent stage of high curvature proportion occur in the effective normal stress to shear stress ratio range of[1.4,1.6].The cumulative energy of pre-peak acoustic emission and damage under different effective normal stress to shear stress ratios increase sharply around the ratio of 1.6,further verifying that the effective normal stress to shear stress ratio range of[1.4,1.6]is the critical threshold range for inducing shear fractures in limestone.
基金funded by the Australian Government,Department of Agriculture,Fisheries and Forestry,and the Cotton Research and Development Corporation through the More Profit from Nitrogen project.
文摘Achieving a sustainable cropping system requires the efficient use of resources,particularly nitrogen(N).Nitrogen fertiliser is applied in most irrigated cotton fields to maximise yield potential,but plant fertiliser recovery can be low.Identifying the crucial pathways of fertiliser remobilisation internally within cotton plants will lead to greater awareness of the plants’ability to match the N demands of the developing fruiting matter.This study investigated the fate of N fertiliser when applied to cotton at various dates,with the goal to improve N fertiliser recovery in a modern transgenic cotton cultivar.15N-labelled urea(10 atom%)was applied at multiple times and harvested at four key cotton growth stages(first square,early bolls,cut-out and maturity).Remobilised N was determined as the difference in the proportion of N fertiliser in individual plant components against the fertiliser utilised by the whole plant.The application of fertiliser N at first square resulted in 23%greater fertiliser N recovery at plant maturity compared to fertiliser N applied 100%pre-plant(P<0.001).The improvement was in-part due to higher N derived from the fertiliser(Ndff%)in the cotton seed(3%).Conversely,the Ndff%was higher in the stem(4%)and petioles(1%)when the fertiliser was applied pre-plant.In total,73%of plant N was remobilised to another plant organ,predominantly the seed(67%).Applying N fertiliser post-planting improved N recovery and lint yield compared to applying all fertiliser pre-plant.
基金the Australian Research Council through the Discovery Grant DP200100727 and Laureate Fellowship FL210100147。
文摘Our understanding of grain-level bursts of plasticity in polycrystals remains limited by current techniques.By employing a modified Synchrotron transmission X-ray Laue diffraction method(beam size larger than the grain size),we tracked grain rotations for the first 1%of tensile strain,in 4400 time steps.We indexed 33 grains and quantified the magnitude and frequency of intermittent bursts of grain rotation.We interpret these events in terms of bursts of plastic deformation.The events are highly coordinated amongst nearby grains,and their frequency and magnitude,as well as the number of grains participating,peaked at around the onset of full plasticity.At this point,7 out of the 10 indexed grains with orientations favorable for twinning showed significant drops in diffracted intensity(a mean value of 8%),due to twin induced re-orientation.For other orientations,20 out of 23 grains displayed bursts attributable to lattice dislocation glide(interpreted in terms of basal and prismatic <α> slip).The mean value of the magnitude of these bursts is∼0.08°,implying accumulated shear strains of the order of 3×10^(-3).These bursts,in many cases,were due to the activation of more than a single slip/twin system within the grain,and co-ordination amongst neighboring grains also involved collaboration between slip and twinning events.
基金supported by the Australian Research Council Linkage Project(No.LP200200717)co sponsored by Newmont Corporation(United States)and Vega Industries(India)+1 种基金the Powder Diffraction Beamline at the Australia’s Nuclear Science and Technology Organisation(No.PDR19870),Australiathe Centre for Microscopy and Microanalysis at the University of Queensland(No.1366),Australia。
文摘Pyrrhotite naturally occurs in various superstructures including magnetic(4C)and non-magnetic(5C,6C)types,each with distinct physicochemical properties and flotation behaviors.Challenges in accurately identifying and quantifying these superstructures hinder the optimization of pyrrhotite depression in flotation processes.To address this critical issue,synchrotron X-ray powder diffraction(S-XRPD)with Rietveld refinement was employed to quantify the distribution of superstructures in the feed and flotation concentrates of a copper–gold ore.To elucidate the mechanisms influencing depression,density functional theory(DFT)calculations were conducted to explore the electronic structures and surface reactivity of the pyrrhotite superstructures toward the adsorption of water,oxygen and hydroxyl ions(OH-)as dominant species present in the flotation process.S-XRPD analysis revealed that flotation recovery rates of pyrrhotite followed the order of 4C<6C<5C.DFT calculations indicated that the Fe 3d and S 3p orbital band centers exhibited a similar trend relative to the Fermi level with 4C being the closest.The Fe3d band center suggested that the 4C structure possessed a more reactive surface toward the oxygen reduction reaction,promoting the formation of hydrophilic Fe-OH sites.The S 3p band center order also implied that xanthate on the non-magnetic 5C and 6C surfaces could oxidize to dixanthogen,increasing hydrophobicity and floatability,while 4C formed less hydrophobic metal-xanthate complexes.Adsorption energy and charge transfer analyses of water,hydroxyl ions and molecular oxygen further supported the high reactivity and hydrophilic nature of 4C pyrrhotite.The strong bonding with hydroxyl ions indicated enhanced surface passivation by hydrophilic Fe–OOH complexes,aligning with the experimentally observed flotation order(4C<6C<5C).These findings provide a compelling correlation between experimental flotation results and electronic structure calculations,delivering crucial insights for optimizing flotation processes and improving pyrrhotite depression.This breakthrough opens up new opportunities to enhance the efficiency of flotation processes in the mining industry.
基金financially supported by the Independent Research fund of Joint National Local Engineering Research Centre for Safe and Precise Coal Mining(Anhui University of Science and Technology)(Grant No.EC2022001)State Key Research Development Program of China(Grant No.2022YFC3004602)the Fundamental Research Funds for the Central Universities(Grant No.2022YJSLJ08).
文摘Understanding dynamic visualization of mining-induced stress is of great significance to disaster prevention and control in coal mining activities.In this study,three theoretical models,including linear,polynomial,and exponential models,are proposed to inverse the mining-induced stress through the acquisition and analysis of hydraulic support stress and micro-seismicity in the coal mining face.The distribution of mining-induced stress in the coal seam are graphed by fitting two key stress parameters including hydraulic support stress and peak stress,and two key zones including goaf zone and in situ stress zone.These key stress parameters and zones are defined based on the critical nodes of the model curve.According to the geological background of Mataihao coal mine in Erdos,Inner Mongolia Autonomous Region,China,the contours of mining-induced stress are graphed through the stress calculation of these three inversion theoretical models.The multi-monitoring data of micro-seismicity,drilling chips,advanced borehole stress and bolts axial force are used to verify the key stress parameters and zones of the theoretical models.It shows that the monitoring data are in good agreement with the distribution of inversed results.It should be emphasized that,if the fault structure exists around the mining face,the mining-induced stress decreases obviously when the mining face is passing through the faults,and the location of the peak stress will be closer to the mining face.The results in this study could provide methods for early prevention of extreme mining-induced stress and disaster control in the mining activities.
基金supported by the Key Project of National Natural Science Foundation of China(U23A20596).
文摘CO_(2)injection in shale oil reservoirs has emerged as a promising technique for simultaneously achieving CO_(2)geological storage and enhancing shale oil recovery.This study investigates the potential of CO_(2)injection into shale oil reservoirs with natural fractures for carbon storage and enhanced oil recovery through a combination of experimental and numerical simulations.It focuses on the synergistic effects on carbon storage capacity and oil recovery efficiency.A series of CO_(2)injection experiments using online NMR T_(2)and stratified T_(2)technology were conducted to validate the feasibility of carbon storage and oil recovery in shale oil reservoirs.The shale samples consist of three distinct pore space systems:kerogen,inorganic matrix,and shale bedding fractures.A coupled multiscale-multiphase simulation model was developed to facilitate a comprehensive analysis of the underlying mechanisms.In the model,kerogen,inorganic matrix,and shale bedding fractures are defined as triple-continuum media.The model integrates the mechanisms of molecular diffusion,adsorption,and viscous flow to accurately represent the mass transport processes during CO_(2)injection in shale oil reservoirs.Within this framework,a series of mass transport partial differential equations were derived to describe the CO_(2)injection process.The finite element method was used to numerically solve these equations,and the proposed model was validated against experimental results.Sensitivity analyses yielded the following results:(1)The shale bedding fractures are not only key reservoir spaces for shale oil but also the key mass transfer channels for shale oil and CO_(2)during CO_(2)injection.Increasing the permeability of the shale bedding fractures can significantly improve oil recovery efficiency and CO_(2)adsorption amount.(2)The kerogen content and organic porosity have a significant impact on CO_(2)adsorption amount and shale oil recovery factor,respectively.(3)High production pressure is essential for maximizing carbon storage capacity.Simultaneously,increasing injection pressure can effectively enhance carbon storage and shale oil recovery.
基金supported by the National Natural Science Foundation of China(Nos.12288102,12203092,12041304,12403060,12203045,12203093,12163001 and 12463007)the Major Science and Technology Program of Xinjiang Uygur Autonomous Region(Nos.2022A03013-3,and 2022A03013-2)+7 种基金the National SKA Program of China(No.2020SKA0120100)the National Key Research and Development Program of China(Nos.2022YFC2205202 and 2021YFC2203502)the Natural Science Foundation of Xinjiang Uygur Autonomous Region(Nos.2022D01B71 and 2022D01B218)the Tianshan Talent Training Program for Young Elite Scientists(No.2023TSYCQNTJ0024)the 2022 Project Xinjiang Uygur Autonomous Region of China for Tianchi Talents,the open research project funded by the Key Laboratory of Xinjiang Uyghur Autonomous Region(No.2021000059)the National Key Research and Development Program(No.2022YFA1603104)The research is partly supported by the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China(MOF)and administrated by the Chinese Academy of Sciences(CAS)Murriyang,CSIRO’s Parkes radio telescope,is part of the Australia Telescope National Facility(https://ror.org/05qajvd42)which is funded by the Australian Government for operation as a National Facility managed by CSIRO.
文摘We present a wideband polarization analysis of the mode-changing pulsar PSR J1938+2213 using the ultra-wideband low-frequency receiver on Murriyang,the Parkes 64 m radio telescope.Polarization profiles for both the burst and weak emission modes are obtained.We find that the pulse widths of the two modes exhibit distinct frequency dependencies:the pulse width increases with frequency in the burst mode,but decreases in the weak mode.The linear and circular polarization fractions also show different trends with frequency between the two modes.Our spectral analysis shows that both modes follow power-law spectra,but with differing spectral indices.
基金Project(52409132) supported by the National Natural Science Foundation of ChinaProject(ZR2024QE018) supported by the Natural Science Foundation of Shandong Province,China+2 种基金Project(BK20240431) supported by Basic Research Program of Jiangsu,ChinaProject(SNKJ2023A07-R14) supported by the Major Key Technical Research Projects of Shandong Energy Group,ChinaProject(2024M751813) supported by China Postdoctoral Science Foundation。
文摘Deep geothermal extraction processes expose rock masses to frequent and significant temperature fluctuations. Developing a comprehensive understanding of the shear fracture mechanisms and crack propagation behaviors in rocks under the influence of cyclic heating is imperative for optimizing geothermal energy extraction. This study encompasses several critical aspects under cyclic heating conditions, including the assessment of stress distribution states, the characterization of two-dimensional fracture paths, the quantitative analysis of three-dimensional damage characteristics on fracture surfaces, and the determination of the fractal dimension of debris generated after the failure of granite. The test results demonstrate that cyclic heating has a pronounced adverse effect on the physical and mechanical properties of granite. Consequently, stress tends to develop and propagate in a direction perpendicular to the two-dimensional fracture path. This leads to an increase in the extent of tensile damage on the fracture surface and accelerates the overall rock failure process. This increases the number of small-sized debris, raises the fractal dimension, and enhances the rock’s rupture degree. In practical enhanced geothermal energy extraction, the real-time monitoring of fracture propagation within the reservoir rock mass is achieved through the analysis of rock debris generated during the staged fracturing process.
基金supported by the National Natural Science Foundation of China(NSFC,Grant Nos.11988101,12203044,and 12473023)by the Leading Innovation and Entrepreneurship Team of Zhejiang Province of China grant No.2023R01008+2 种基金by Key R&D Program of Zhejiang grant No.2024SSYS0012by the University Annual Scientific Research Plan of Anhui Province(No.2023AH030052,No.2022AH010013)Cultivation Project for FAST Scientific Payoff and Research Achievement of CAMS-CAS。
文摘We present the first search for pulsed CH maser emission potentially stimulated by PSR J1644-4559,conducted using the ultra-wide-bandwidth low-frequency receiver on Murriyang,CSIRO's Parkes Radio Telescope.Observations targeted three CHΛ-doublet transitions at 3264,3335,and 3349 MHz,with a variability timescale of78 ms.We detected ten CH emission features at 3335 and 3349 MHz,and seven features at 3264 MHz,during both pulsar-ON and pulsar-OFF phases.The observed velocities align with the OH emission and absorption reported by a previous study,suggesting a close spatial association between CH and OH molecules.The derived column densities for CH clouds within the Parkes beam range from 0.05 to 9.8×10^(13)cm^(-2),indicating that these clouds are likely in diffuse and translucent states.Upper limits for CH column densities within the pulsar beam ranged from 0.3 to 9.8×10^(13)cm^(-2).Comparison of these column densities suggests that CH clouds may exhibit clumpiness and substructure.No significant stimulated emission feature was detected in the optical depth spectra.Additionally,as part of our search for pulsed stimulated emission,we investigated the potential CH absorption of the pulsar signal and found none,in agreement with astrophysical expectations.The upper limits for the potential maser amplification factors towards PSR J1644-4559 at 3264,3335,and 3349 MHz are 1.014,1.009,and 1.009,respectively.This study demonstrates the feasibility of detecting pulsed CH maser emission in the interstellar medium stimulated by pulsar photons.
