Improving knowledge on the ability of bioengineering structures made of willow cuttings to enhance efficient and sustainable sediment trapping in marly gullies in the Southern French Alps under a mountainous Mediterra...Improving knowledge on the ability of bioengineering structures made of willow cuttings to enhance efficient and sustainable sediment trapping in marly gullies in the Southern French Alps under a mountainous Mediterranean climate, to decreasesediment trapped per experiment, the mean annual values reached 0.25, 0.14 and 0.08 m3 yr-1 in experiments C, A and B, respectively. Maximum values for one structure reached 1.94 m3 per year in experiment C. The significance of the volumes ofsediment yield at their outlets, is a key issue today for the international scientific community working in geosciences and ecology. This study therefore aims to assess three real-size experiments(A, B and C) carried out between 2003 and 2013 in this environment. A total of 157 bioengineering structures using purple and white willow(Salix purpurea and Salix incana)cuttings – which have been shown to resprout and survive more than 2 years after their installation,corresponding to brush layers with brush mats on wooden sills(BLM), 1.2 m wide and 2 m long,installed on the floors of 33 experimental marly gullies, were monitored. The results showed that sediment trapping occurred upstream of the vegetation barriers from the 1 st year onwards.Considering the depth of sediment trapped per experiment, the mean annual values reached 11.2 cm yr-1 after 3 years in experiment A, 7.7 cm yr-1 after 2–4 years in experiment C and 5.1 cm yr-1 after 5 years in experiment B. Occasionally, BLMs showed that they could trap up to 16 and 15 cm yr-1 in experiments A and C, respectively. Considering the volumes oftrapped sediment and the sustainability of sediment trapping are discussed, and rules for bioengineering strategies are proposed.展开更多
Dear Editor,This letter proposes a convex optimization-based model predictive control(MPC)autonomous guidance method for the Mars ascent vehicle(MAV).We use the modified chebyshev-picard iteration(MCPI)to solve optimi...Dear Editor,This letter proposes a convex optimization-based model predictive control(MPC)autonomous guidance method for the Mars ascent vehicle(MAV).We use the modified chebyshev-picard iteration(MCPI)to solve optimization sub-problems within the MPC framework,eliminating the dynamic constraints in solving the optimal control problem and enhancing the convergence performance of the algorithm.Moreover,this method can repeatedly perform trajectory optimization calculations at a high frequency,achieving timely correction of the optimal control command.Numerical simulations demonstrate that the method can satisfy the requirements of rapid computation and reliability for the MAV system when considering uncertainties and perturbations.展开更多
Medically assisted reproduction(MAR)techniques are highly dependent on the sperm quantity and quality.Low sperm concentrations can be bypassed at least to some point by the usage of more sophisticated MAR techniques l...Medically assisted reproduction(MAR)techniques are highly dependent on the sperm quantity and quality.Low sperm concentrations can be bypassed at least to some point by the usage of more sophisticated MAR techniques like intracytoplasmic sperm injection(ICSI).Compared to this,disruptions in established indicators of sperm quality like motility or morphology pose greater challenges for the therapy of couple infertility.展开更多
In this study, we present an innovative Mars Ionosphere-Thermosphere Model(MITM), which is a time-dependent, threedimensional(3-D) model that comprehensively represents the self-consistently coupled thermosphere and i...In this study, we present an innovative Mars Ionosphere-Thermosphere Model(MITM), which is a time-dependent, threedimensional(3-D) model that comprehensively represents the self-consistently coupled thermosphere and ionosphere of Mars within the altitude range of 70-300 km. The model incorporates an extensive range of parameters, including neutral number densities of CO_(2), CO,O, O_(2), N_(2), NO, N(^(2)D), N(^(4)S), Ar, and He;ion number densities of CO_(2)^(+), CO^(+), O^(+), O_(2)^(+), N_(2)^(+), NO^(+), N^(+) ions, and electrons;neutral temperature;and neutral wind fields. The MITM code employs a high-resolution grid system in a spherical geographical coordinate system, with a horizontal resolution of 5° latitude by 7.5° longitude. This altitude-resolved grid system enables accurate depiction of spatial variations in the Martian thermosphere and ionosphere. To showcase the capabilities of the MITM, we present two simulation cases: one during the equinox and another during the solstice. Both simulations reproduce key features of the Martian thermosphere and ionosphere including the characteristics of horizontal circulation, diurnal variations in chemical composition, and distribution of electron density. The MITM offers a robust framework for understanding the intricate interactions and processes that shape the Mars thermosphere and ionosphere,which are crucial for enhancing our understanding of Martian upper atmosphere and ionosphere.展开更多
The InSight mission has obtained seismic data from Mars,offering new insights into the planet’s internal structure and seismic activity.However,the raw data released to the public contain various sources of noise,suc...The InSight mission has obtained seismic data from Mars,offering new insights into the planet’s internal structure and seismic activity.However,the raw data released to the public contain various sources of noise,such as ticks and glitches,which hamper further seismological studies.This paper presents step-by-step processing of InSight’s Very Broad Band seismic data,focusing on the suppression and removal of non-seismic noise.The processing stages include tick noise removal,glitch signal suppression,multicomponent synchronization,instrument response correction,and rotation of orthogonal components.The processed datasets and associated codes are openly accessible and will support ongoing efforts to explore the geophysical properties of Mars and contribute to the broader field of planetary seismology.展开更多
1 A possible ancient shoreline has been found in the region of Mars explored by the Chinese rover,Zhurong,providing further evidence that an ocean may once have covered a vast area of the lowlands in the planet's ...1 A possible ancient shoreline has been found in the region of Mars explored by the Chinese rover,Zhurong,providing further evidence that an ocean may once have covered a vast area of the lowlands in the planet's northern part.2 The rover landed in southern Utopia Planitia in May 2021 and remained active for almost a year.Researchers studying data from the rover have found clues of an ancient ocean or liquid water as recently as 400,000 years ago.展开更多
Recurring Slope Lineae(RSL)are seasonally observed dark streaks on the Martian surface that exhibit distinct spatial and temporal distribution characteristics.Exploring their formation mechanisms can deepen our unders...Recurring Slope Lineae(RSL)are seasonally observed dark streaks on the Martian surface that exhibit distinct spatial and temporal distribution characteristics.Exploring their formation mechanisms can deepen our understanding of surface activity on Mars and provide scientific basis for future Mars exploration.This study aims to gain a comprehensive understanding of the spatial and temporal distribution characteristics and formation mechanisms of RSL by reviewing relevant literature and synthesizing various viewpoints and experimental results.RSL typically appear during warm seasons,disappear during cold seasons,and repeat over multiple Martian years.The formation mechanisms can be broadly categorized into three types:dry mode,wet mode,and mixed mode.However,a definitive explanation for the formation of RSL is still lacking,and both the dry and wet models have their respective limitations.It is likely that the formation of RSL is the result of the combined action of multiple mechanisms.The next step should be to search for terrestrial analogs of RSL and conduct research at high spatial and temporal resolutions to understand the forming processes of RSL.展开更多
Hot flow anomalies(HFAs)are not only a terrestrial phenomenon,but also a solar-system-wide phenomenon,one that can cause significant perturbations in planetary magnetospheres and ionospheres.In this study,based on the...Hot flow anomalies(HFAs)are not only a terrestrial phenomenon,but also a solar-system-wide phenomenon,one that can cause significant perturbations in planetary magnetospheres and ionospheres.In this study,based on the observations of Mars Atmosphere and Volatile EvolutioN(MAVEN)mission in the region upstream of the Martian bow shock from the year 2014 to 2020,we have investigated the statistical properties of HFAs around Mars.Our results show that HFAs can be found in a wide region of Mars,from the dayside to the terminator region.On average,these HFAs last 63 seconds,with a thickness of 28 local proton gyroradii.They are more prevalent when the ambient solar wind is denser and faster,and usually occur when the interplanetary magnetic field magnitude is between 1-4 nT.Martian HFAs can also lead to solar wind dynamics multiplying in pressure by factors of ten within only tens of seconds,which could significantly influence the heights of the Martian ionopause and induced magnetosphere boundary.By comparing HFAs around Earth,we suggest that these phenomena are primarily governed by solar wind dynamics rather than local planetary conditions.展开更多
A brief concept study of a modular research aircraft with potential applications to Mars exploration is conducted.Considered are dimensional and mass constraints of a launch vehicle payload compartment,mission radius ...A brief concept study of a modular research aircraft with potential applications to Mars exploration is conducted.Considered are dimensional and mass constraints of a launch vehicle payload compartment,mission radius extension applying ground mobility and overall flight envelope extension using fixed-wing aerodynamics.Also,some lessons learned from NASA Mars Ingenuity flights are considered and addressed with few solutions.The modular system includes a fixed-wing design along with a number of smaller autonomous quadcopter UAVs,encapsulated inside a geodesic spherical support through a gimbal mechanism for ground mobility.Analyzed is the feasibility of allocating to these mini drones both scout and mapping tasks of complex terrain such as crater walls,canyons and cave systems that might hold key insights into the planet's geologic history.Once docked with the mothership fixed wing,the mini drones serve as a distributed propulsion system,for vertical take-off and landing and control,completely replacing control surfaces on the flying wing itself,its engine and landing gear.CFD and structural simulations have demonstrated the flight-ability in Mars conditions of a flying wing design along with scout drone prototypes with a pentagon-hexagon geodesic shell.Also demonstrated is the great flexibility of the suggested modular approach for various research applications and mission profiles on Mars and other planets or moons,improving overall reliability and mission radius.展开更多
基金Electricitéde France(EDF)Agence de l’eau Rh?ne+3 种基金Méditerranée et CorseRégion Provence-Alpes-Cote-d’Azurthe European Union("L’Europe s’engage en PACA avec le Fonds Européen de Développement Régional"FEDER program)the Ministère de l’environnement,de l’énergie et de la mer(MEEM)
文摘Improving knowledge on the ability of bioengineering structures made of willow cuttings to enhance efficient and sustainable sediment trapping in marly gullies in the Southern French Alps under a mountainous Mediterranean climate, to decreasesediment trapped per experiment, the mean annual values reached 0.25, 0.14 and 0.08 m3 yr-1 in experiments C, A and B, respectively. Maximum values for one structure reached 1.94 m3 per year in experiment C. The significance of the volumes ofsediment yield at their outlets, is a key issue today for the international scientific community working in geosciences and ecology. This study therefore aims to assess three real-size experiments(A, B and C) carried out between 2003 and 2013 in this environment. A total of 157 bioengineering structures using purple and white willow(Salix purpurea and Salix incana)cuttings – which have been shown to resprout and survive more than 2 years after their installation,corresponding to brush layers with brush mats on wooden sills(BLM), 1.2 m wide and 2 m long,installed on the floors of 33 experimental marly gullies, were monitored. The results showed that sediment trapping occurred upstream of the vegetation barriers from the 1 st year onwards.Considering the depth of sediment trapped per experiment, the mean annual values reached 11.2 cm yr-1 after 3 years in experiment A, 7.7 cm yr-1 after 2–4 years in experiment C and 5.1 cm yr-1 after 5 years in experiment B. Occasionally, BLMs showed that they could trap up to 16 and 15 cm yr-1 in experiments A and C, respectively. Considering the volumes oftrapped sediment and the sustainability of sediment trapping are discussed, and rules for bioengineering strategies are proposed.
基金supported by the National Defense Basic Scientific Research Program(JCKY2021603B030)the National Natural Science Foundation of China(62273118,12150008)the Natural Science Foundation of Heilongjiang Province(LH2022F023).
文摘Dear Editor,This letter proposes a convex optimization-based model predictive control(MPC)autonomous guidance method for the Mars ascent vehicle(MAV).We use the modified chebyshev-picard iteration(MCPI)to solve optimization sub-problems within the MPC framework,eliminating the dynamic constraints in solving the optimal control problem and enhancing the convergence performance of the algorithm.Moreover,this method can repeatedly perform trajectory optimization calculations at a high frequency,achieving timely correction of the optimal control command.Numerical simulations demonstrate that the method can satisfy the requirements of rapid computation and reliability for the MAV system when considering uncertainties and perturbations.
文摘Medically assisted reproduction(MAR)techniques are highly dependent on the sperm quantity and quality.Low sperm concentrations can be bypassed at least to some point by the usage of more sophisticated MAR techniques like intracytoplasmic sperm injection(ICSI).Compared to this,disruptions in established indicators of sperm quality like motility or morphology pose greater challenges for the therapy of couple infertility.
基金This work is supported by the B-type Strategic Priority Program of the Chinese Academy of Sciences (Grant No. XDB4100000)the pre-research Project on Civil Aerospace Technologies No. D020105 funded by CNSAthe Strategic Priority Research Program of Chinese Academy of Sciences (Grant XDA17010404, XDA17010201)。
文摘In this study, we present an innovative Mars Ionosphere-Thermosphere Model(MITM), which is a time-dependent, threedimensional(3-D) model that comprehensively represents the self-consistently coupled thermosphere and ionosphere of Mars within the altitude range of 70-300 km. The model incorporates an extensive range of parameters, including neutral number densities of CO_(2), CO,O, O_(2), N_(2), NO, N(^(2)D), N(^(4)S), Ar, and He;ion number densities of CO_(2)^(+), CO^(+), O^(+), O_(2)^(+), N_(2)^(+), NO^(+), N^(+) ions, and electrons;neutral temperature;and neutral wind fields. The MITM code employs a high-resolution grid system in a spherical geographical coordinate system, with a horizontal resolution of 5° latitude by 7.5° longitude. This altitude-resolved grid system enables accurate depiction of spatial variations in the Martian thermosphere and ionosphere. To showcase the capabilities of the MITM, we present two simulation cases: one during the equinox and another during the solstice. Both simulations reproduce key features of the Martian thermosphere and ionosphere including the characteristics of horizontal circulation, diurnal variations in chemical composition, and distribution of electron density. The MITM offers a robust framework for understanding the intricate interactions and processes that shape the Mars thermosphere and ionosphere,which are crucial for enhancing our understanding of Martian upper atmosphere and ionosphere.
基金supported by the National Key R&D Program of China(Nos.2022YFF 0503203 and 2024YFF0809900)the Research Funds of the Institute of Geophysics,China Earthquake Administration(No.DQJB24X28)the National Natural Science Foundation of China(Nos.42474226 and 42441827).
文摘The InSight mission has obtained seismic data from Mars,offering new insights into the planet’s internal structure and seismic activity.However,the raw data released to the public contain various sources of noise,such as ticks and glitches,which hamper further seismological studies.This paper presents step-by-step processing of InSight’s Very Broad Band seismic data,focusing on the suppression and removal of non-seismic noise.The processing stages include tick noise removal,glitch signal suppression,multicomponent synchronization,instrument response correction,and rotation of orthogonal components.The processed datasets and associated codes are openly accessible and will support ongoing efforts to explore the geophysical properties of Mars and contribute to the broader field of planetary seismology.
文摘1 A possible ancient shoreline has been found in the region of Mars explored by the Chinese rover,Zhurong,providing further evidence that an ocean may once have covered a vast area of the lowlands in the planet's northern part.2 The rover landed in southern Utopia Planitia in May 2021 and remained active for almost a year.Researchers studying data from the rover have found clues of an ancient ocean or liquid water as recently as 400,000 years ago.
基金Supported by the National Natural Science Foundation(No.42272340).
文摘Recurring Slope Lineae(RSL)are seasonally observed dark streaks on the Martian surface that exhibit distinct spatial and temporal distribution characteristics.Exploring their formation mechanisms can deepen our understanding of surface activity on Mars and provide scientific basis for future Mars exploration.This study aims to gain a comprehensive understanding of the spatial and temporal distribution characteristics and formation mechanisms of RSL by reviewing relevant literature and synthesizing various viewpoints and experimental results.RSL typically appear during warm seasons,disappear during cold seasons,and repeat over multiple Martian years.The formation mechanisms can be broadly categorized into three types:dry mode,wet mode,and mixed mode.However,a definitive explanation for the formation of RSL is still lacking,and both the dry and wet models have their respective limitations.It is likely that the formation of RSL is the result of the combined action of multiple mechanisms.The next step should be to search for terrestrial analogs of RSL and conduct research at high spatial and temporal resolutions to understand the forming processes of RSL.
基金supported by NSFC grants 42274219,42330207,42374213 and 42130204Shenzhen Key Laboratory Launching Project(No.ZDSYS20210702140800001)+1 种基金supported by Frontier Science Center of matter behave in space environmentthe support of the National Key Research and Development Program of China(No.2022YFA1604600).
文摘Hot flow anomalies(HFAs)are not only a terrestrial phenomenon,but also a solar-system-wide phenomenon,one that can cause significant perturbations in planetary magnetospheres and ionospheres.In this study,based on the observations of Mars Atmosphere and Volatile EvolutioN(MAVEN)mission in the region upstream of the Martian bow shock from the year 2014 to 2020,we have investigated the statistical properties of HFAs around Mars.Our results show that HFAs can be found in a wide region of Mars,from the dayside to the terminator region.On average,these HFAs last 63 seconds,with a thickness of 28 local proton gyroradii.They are more prevalent when the ambient solar wind is denser and faster,and usually occur when the interplanetary magnetic field magnitude is between 1-4 nT.Martian HFAs can also lead to solar wind dynamics multiplying in pressure by factors of ten within only tens of seconds,which could significantly influence the heights of the Martian ionopause and induced magnetosphere boundary.By comparing HFAs around Earth,we suggest that these phenomena are primarily governed by solar wind dynamics rather than local planetary conditions.
基金funded by the Russian Science Foundation(No.22–49-02047)。
文摘A brief concept study of a modular research aircraft with potential applications to Mars exploration is conducted.Considered are dimensional and mass constraints of a launch vehicle payload compartment,mission radius extension applying ground mobility and overall flight envelope extension using fixed-wing aerodynamics.Also,some lessons learned from NASA Mars Ingenuity flights are considered and addressed with few solutions.The modular system includes a fixed-wing design along with a number of smaller autonomous quadcopter UAVs,encapsulated inside a geodesic spherical support through a gimbal mechanism for ground mobility.Analyzed is the feasibility of allocating to these mini drones both scout and mapping tasks of complex terrain such as crater walls,canyons and cave systems that might hold key insights into the planet's geologic history.Once docked with the mothership fixed wing,the mini drones serve as a distributed propulsion system,for vertical take-off and landing and control,completely replacing control surfaces on the flying wing itself,its engine and landing gear.CFD and structural simulations have demonstrated the flight-ability in Mars conditions of a flying wing design along with scout drone prototypes with a pentagon-hexagon geodesic shell.Also demonstrated is the great flexibility of the suggested modular approach for various research applications and mission profiles on Mars and other planets or moons,improving overall reliability and mission radius.
