The Square Kilometre Array(SKA)has the potential to revolutionize astronomical research through its unparalleled precision.A critical aspect of SKA imaging is the computation of the UVW coordinates,which must be accur...The Square Kilometre Array(SKA)has the potential to revolutionize astronomical research through its unparalleled precision.A critical aspect of SKA imaging is the computation of the UVW coordinates,which must be accurate and reliable for the development of the SKA scientific data processor.Katpoint is the current method used to calculate UVW in Meer KAT.Using a pseudo-source,we employ a simple cross-product method to determine UVWs.In this study,we explore the applicability of Katpoint for SKA1-low and SKA1-mid and evaluate its precision.The conventional method,CALC/Omni UV,and Katpoint were quantitatively assessed through simulations.The results indicate that Katpoint exhibits substantial accuracy with MeerKAT compared to traditional techniques.However,its precision is slightly inadequate for the long baselines of SKA1.We improved the precision of Katpoint by identifying optimal offset values for pseudo-sources on the SKA1 telescope through simulation,finding a 0°.11 offset suitable for SKA1-Mid and a 0°.045 offset for SKA1-Low.Final result validations demonstrate that these adjustments render the computational accuracy fully comparable to the standard CALC/Omni UV method,which would meet the requirements of SKA high-precision imaging and offer a solution for high-precision imaging in radio interferometers.展开更多
Position, width and fragmentation level of fracture zones and position, sig-nificance and characteristic distance of fractures were aimed to determine in a carbonate aquifer. These are fundamental parameters, e.g. in ...Position, width and fragmentation level of fracture zones and position, sig-nificance and characteristic distance of fractures were aimed to determine in a carbonate aquifer. These are fundamental parameters, e.g. in hydrogeological modelling of aquifers, due to their role in subsurface water movements. The description of small scale fracture systems is however a challenging task. In the test area (Kádárta, Bakony Mts, Hungary), two methods proved to be applicable to get reasonable information about the fractures: Electrical Resistivity Tomography (ERT) and Pricking-Probe (PriP). PriP is a simple mechanical tool which has been successfully applied in archaeological investigations. ERT results demonstrated its applicability in this small scale fracture study. PriP proved to be a good verification tool both for fracture zone mapping and detecting fractures, but in certain areas, it produced different results than the ERT. The applicability of this method has therefore to be tested yet, although its problems most probably origin from human activity which reorganises the near-surface debris distribution. In the test site, both methods displayed fracture zones including a very characteristic one and a number of individual fractures and determined their characteristic distance and significance. Both methods prove to be able to produce hydrogeologically important parameters even individually, but their simultaneous application is recommended to decrease the possible discrepancies.展开更多
Clinopyroxene-enriched upper mantle xenoliths classified as wehrlites are common(~20% of all xenoliths) in the central part of the Nograd-G(o| ")m(o|")r Volcanic Field(NGVF),situated in the northern margin o...Clinopyroxene-enriched upper mantle xenoliths classified as wehrlites are common(~20% of all xenoliths) in the central part of the Nograd-G(o| ")m(o|")r Volcanic Field(NGVF),situated in the northern margin of the Pannonian Basin in northern Hungary and southern Slovakia.In this study,we thoroughly investigated 12 wehrlite xenoliths,two from each wehrlite-bearing occurrence,to determine the conditions of their formation.Specific textural features,including clinopyroxene-rich patches in an olivine-rich lithology,orthopyroxene remnants in the cores of newlyformed clinopyroxenes and vermicular spinel forms all suggest that wehrlites were formed as a result of intensive interaction between a metasomatic agent and the peridotite wall rock.Based on the major and trace element geochemistry of the rock-forming minerals,significant enrichment in basaltic(Fe,Mn,Ti) and high field strength elements(Nb,Ta,Hf,Zr) was observed,compared to compositions of common lherzolite xenoliths.The presence of orthopyroxene remnants and geochemical trends in rock-forming minerals suggest that the metasomatic process ceased before complete wehrlitization was achieved.The composition of the metasomatic agent is interpreted to be a mafic silicate melt,which was further confirmed by numerical modelling of trace elements using the plate model.The model results also show that the melt/rock ratio played a key role in the degree of petrographic and geochemical transformation.The lack of equilibrium and the conclusions drawn by using variable lherzolitic precursors in the model both suggest that wehrlitization was the last event that occurred shortly before xenolith entrainment in the host mafic melt.We suggest that the wehrlitization and the Plio-Pleistocene basaltic volcanism are related to the same magmatic event.展开更多
Introduction:Forest cover in Hungary has increased from 1.1 to 2.0 million hectares during the last century.The EU(European Union)promotes further afforestation;thus,15,000–18,000 ha are being forested each year,main...Introduction:Forest cover in Hungary has increased from 1.1 to 2.0 million hectares during the last century.The EU(European Union)promotes further afforestation;thus,15,000–18,000 ha are being forested each year,mainly in the Hungarian Great Plain.In terms of species used for afforestation,poplar plantations are preferred over native oak woodlands.The groundwater uptake of trees can be a significant water balance element of forested areas in shallow groundwater environments within the Hungarian Great Plain.Forests can cause water table depressions and subsurface salt accumulation in areas with negative water balance.This study examined the hydrological impact of forest cover in the Hungarian Great Plain.Within the framework of this research,climatic water balance,water table depth and salinity,subsoil layering,tree species and stand age were analysed as influencing factors.This paper compares the effect which an oak forest,a poplar plantation and a pasture have on groundwater uptake and salt accumulation.Results:The water table level was roughly 0.4–0.5 m lower beneath the oak forest and the poplar plantation than it was beneath the pasture.Forest groundwater use was 1.5–2 times higher than that of grassland.Groundwater uptake of oak forest was greater than that of poplar plantation during the monitoring period.Salt accumulation,which shows water use in the longer run,was slightly higher for poplar in deeper layers.Conclusions:The greater amount of groundwater used by trees does not lead to a higher salt uptake as only a slight accumulation of salt was measured beneath the forests.Overall,hybrid poplar was slightly less favourable than native oak when considering salinization effects.However,even greater groundwater uptake by trees over longer timescales could cause more significant salt accumulation under pronounced drought conditions due to climate change.展开更多
基金supported by the China National SKA Programme(2020SKA0110300)the National Natural Science Foundation of China(NSFC,Grant Nos.12433012 and 12373097)the Guangzhou Science and Technology Funds(2023A03J0016)。
文摘The Square Kilometre Array(SKA)has the potential to revolutionize astronomical research through its unparalleled precision.A critical aspect of SKA imaging is the computation of the UVW coordinates,which must be accurate and reliable for the development of the SKA scientific data processor.Katpoint is the current method used to calculate UVW in Meer KAT.Using a pseudo-source,we employ a simple cross-product method to determine UVWs.In this study,we explore the applicability of Katpoint for SKA1-low and SKA1-mid and evaluate its precision.The conventional method,CALC/Omni UV,and Katpoint were quantitatively assessed through simulations.The results indicate that Katpoint exhibits substantial accuracy with MeerKAT compared to traditional techniques.However,its precision is slightly inadequate for the long baselines of SKA1.We improved the precision of Katpoint by identifying optimal offset values for pseudo-sources on the SKA1 telescope through simulation,finding a 0°.11 offset suitable for SKA1-Mid and a 0°.045 offset for SKA1-Low.Final result validations demonstrate that these adjustments render the computational accuracy fully comparable to the standard CALC/Omni UV method,which would meet the requirements of SKA high-precision imaging and offer a solution for high-precision imaging in radio interferometers.
文摘Position, width and fragmentation level of fracture zones and position, sig-nificance and characteristic distance of fractures were aimed to determine in a carbonate aquifer. These are fundamental parameters, e.g. in hydrogeological modelling of aquifers, due to their role in subsurface water movements. The description of small scale fracture systems is however a challenging task. In the test area (Kádárta, Bakony Mts, Hungary), two methods proved to be applicable to get reasonable information about the fractures: Electrical Resistivity Tomography (ERT) and Pricking-Probe (PriP). PriP is a simple mechanical tool which has been successfully applied in archaeological investigations. ERT results demonstrated its applicability in this small scale fracture study. PriP proved to be a good verification tool both for fracture zone mapping and detecting fractures, but in certain areas, it produced different results than the ERT. The applicability of this method has therefore to be tested yet, although its problems most probably origin from human activity which reorganises the near-surface debris distribution. In the test site, both methods displayed fracture zones including a very characteristic one and a number of individual fractures and determined their characteristic distance and significance. Both methods prove to be able to produce hydrogeologically important parameters even individually, but their simultaneous application is recommended to decrease the possible discrepancies.
基金This research was financially facilitated by Orlando Vasellisupported by the Bolyai Postdoctoral Fellowship Program,a Marie Curie International Reintegration Grant(Grant No.NAMS-230937)+3 种基金a postdoctoral grant(Grant No.PD101683)of the Hungarian Scientific Research Found(OTKA)to I.J.K.as well as a grant of the Hungarian Scientific Research Found(Grant No.78425)to Cs.supported by a grant from the U.S.National Science Foundation(EAR1624589)to R.J.supported by the GINOP-2.3.2-152016-00009 research program。
文摘Clinopyroxene-enriched upper mantle xenoliths classified as wehrlites are common(~20% of all xenoliths) in the central part of the Nograd-G(o| ")m(o|")r Volcanic Field(NGVF),situated in the northern margin of the Pannonian Basin in northern Hungary and southern Slovakia.In this study,we thoroughly investigated 12 wehrlite xenoliths,two from each wehrlite-bearing occurrence,to determine the conditions of their formation.Specific textural features,including clinopyroxene-rich patches in an olivine-rich lithology,orthopyroxene remnants in the cores of newlyformed clinopyroxenes and vermicular spinel forms all suggest that wehrlites were formed as a result of intensive interaction between a metasomatic agent and the peridotite wall rock.Based on the major and trace element geochemistry of the rock-forming minerals,significant enrichment in basaltic(Fe,Mn,Ti) and high field strength elements(Nb,Ta,Hf,Zr) was observed,compared to compositions of common lherzolite xenoliths.The presence of orthopyroxene remnants and geochemical trends in rock-forming minerals suggest that the metasomatic process ceased before complete wehrlitization was achieved.The composition of the metasomatic agent is interpreted to be a mafic silicate melt,which was further confirmed by numerical modelling of trace elements using the plate model.The model results also show that the melt/rock ratio played a key role in the degree of petrographic and geochemical transformation.The lack of equilibrium and the conclusions drawn by using variable lherzolitic precursors in the model both suggest that wehrlitization was the last event that occurred shortly before xenolith entrainment in the host mafic melt.We suggest that the wehrlitization and the Plio-Pleistocene basaltic volcanism are related to the same magmatic event.
基金Research has been supported by the following funds:OTKA(NN 79835)and“Agrárklíma.2”(VKSZ_12-1-2013-0034)EFOP-3.6.2-16-2017-00018 EU-national joint founded research project.This paper was also supported by the János Bolyai Scholarship of the Hungarian Academy of SciencesThe research of Zoltán Gribovszki was supported by the European Union and the State of Hungary,co-financed by the European Social Fund in the framework of TÁMOP 4.2.4.A/2-11-1-2012-0001“National Excellence Program.”The work of KB and PCS was supported by the Postdoctoral Research Programme PD-029/2015 of the Hungarian Academy of Sciences.
文摘Introduction:Forest cover in Hungary has increased from 1.1 to 2.0 million hectares during the last century.The EU(European Union)promotes further afforestation;thus,15,000–18,000 ha are being forested each year,mainly in the Hungarian Great Plain.In terms of species used for afforestation,poplar plantations are preferred over native oak woodlands.The groundwater uptake of trees can be a significant water balance element of forested areas in shallow groundwater environments within the Hungarian Great Plain.Forests can cause water table depressions and subsurface salt accumulation in areas with negative water balance.This study examined the hydrological impact of forest cover in the Hungarian Great Plain.Within the framework of this research,climatic water balance,water table depth and salinity,subsoil layering,tree species and stand age were analysed as influencing factors.This paper compares the effect which an oak forest,a poplar plantation and a pasture have on groundwater uptake and salt accumulation.Results:The water table level was roughly 0.4–0.5 m lower beneath the oak forest and the poplar plantation than it was beneath the pasture.Forest groundwater use was 1.5–2 times higher than that of grassland.Groundwater uptake of oak forest was greater than that of poplar plantation during the monitoring period.Salt accumulation,which shows water use in the longer run,was slightly higher for poplar in deeper layers.Conclusions:The greater amount of groundwater used by trees does not lead to a higher salt uptake as only a slight accumulation of salt was measured beneath the forests.Overall,hybrid poplar was slightly less favourable than native oak when considering salinization effects.However,even greater groundwater uptake by trees over longer timescales could cause more significant salt accumulation under pronounced drought conditions due to climate change.
