The Infrared Hyperspectral Atmospheric SounderⅡ(HIRAS-Ⅱ)is the key equipment on FengYun-3E(FY-3E)satellite,which can realize vertical atmospheric detection,featuring hyper spectral,high sensitivity and high precisio...The Infrared Hyperspectral Atmospheric SounderⅡ(HIRAS-Ⅱ)is the key equipment on FengYun-3E(FY-3E)satellite,which can realize vertical atmospheric detection,featuring hyper spectral,high sensitivity and high precision.To ensure its accuracy of detection,it is necessary to correlate their thermal models to in-orbit da⁃ta.In this work,an investigation of intelligent correlation method named Intelligent Correlation Platform for Ther⁃mal Model(ICP-TM)was established,the advanced Kriging surrogate model and efficient adaptive region opti⁃mization algorithm were introduced.After the correlation with this method for FY-3E/HIRAS-Ⅱ,the results indi⁃cate that compared with the data in orbit,the error of the thermal model has decreased from 5 K to within±1 K in cold case(10℃).Then,the correlated model is validated in hot case(20℃),and the correlated model exhibits good universality.This correlation precision is also much superiors to the general ones like 3 K in other similar lit⁃erature.Furthermore,the process is finished in 8 days using ICP-TM,the efficiency is much better than 3 months based on manual.The results show that the proposed approach significantly enhances the accuracy and efficiency of thermal model,this contributes to the precise thermal control of subsequent infrared optical payloads.展开更多
Large unmanned underwater vehicles can carry big payloads for varied missions and it is desirable for them to possess an upright orientation during payload release.Their attitude can hardly be maintained during and af...Large unmanned underwater vehicles can carry big payloads for varied missions and it is desirable for them to possess an upright orientation during payload release.Their attitude can hardly be maintained during and after the phase of payload release.Releasing a payload from the vehicle induces uncertainties not only in rigid-body parameters,e.g,the moment of inertia tensor due to the varying distribution of the masses on board the vehicle,but also in the hydrodynamic derivatives due to the vehicle’s varying geometric profile.A nonlinear attitude stabilizer that is robust to these time-varying model uncertainties is proposed in this paper.Stability is guaranteed via Lyapunov stability theory.The simulation results verify the effectiveness of the proposed approach.展开更多
A robust attitude control methodology is proposed for satellite system with double rotary payloads. The dynamic model is built by the Newton-Euler method and then the dynamic interconneetion between satellite＇s main ...A robust attitude control methodology is proposed for satellite system with double rotary payloads. The dynamic model is built by the Newton-Euler method and then the dynamic interconneetion between satellite＇s main body and payloads is described precisely. A nonlinear disturbance observer is designed for satellite＇s main body to estimate disturbance torque acted by motion of payloads. Meanwhile, the adaptive fast nonsingular terminal sliding-mode attitude stabilization controller is proposed for satellite＇s main body to quicken convergence speed of state variables. Similarly, the adaptive fast nonsingular terminal sliding-mode attitude maneuver controller is designed for each payload to weaken the disturbance effect of motion of satellite＇s main body. Simulation results verify the effectiveness of the proposed method.展开更多
China’s first Mars exploration mission is scheduled to be launched in 2020.It aims not only to conduct global and comprehensive exploration of Mars by use of an orbiter but also to carry out in situ observation of ke...China’s first Mars exploration mission is scheduled to be launched in 2020.It aims not only to conduct global and comprehensive exploration of Mars by use of an orbiter but also to carry out in situ observation of key sites on Mars with a rover.This mission focuses on the following studies:topography,geomorphology,geological structure,soil characteristics,water-ice distribution,material composition,atmosphere and ionosphere,surface climate,environmental characteristics,Mars internal structure,and Martian magnetic field.It is comprised of an orbiter,a lander,and a rover equipped with 13 scientific payloads.This article will give an introduction to the mission including mission plan,scientific objectives,scientific payloads,and its recent development progress.展开更多
In this paper, robust control problem is addressed for quad-rotor delivering unknown time-varying payloads. Firstly, the model of a quad-rotor carrying payloads is built. Dynamics of the payloads are treated as distur...In this paper, robust control problem is addressed for quad-rotor delivering unknown time-varying payloads. Firstly, the model of a quad-rotor carrying payloads is built. Dynamics of the payloads are treated as disturbances and added into the model of the quad-rotor. Secondly, to enhance system robust-ness, the extended state observer (ESO) is applied to estimate the disturbances from the payloads for feedback compensation. Then a type of predictive controller targeting multiple-input-multiple-output (MIMO) system is developed to degrade the influences caused by sudden changes from load-ing/dropping of the payloads. Finally, by making comparison with the con-ventional cascade proportional-integral-derivative (CPID) and the sliding mode control (SMC) approaches, superiority of the scheme developed is va-lidated. The simulation results indicate that the CPID method shows poor performance on attitude stabilization and the SMC shows input chattering phenomenon even it can achieve satisfied control performances.展开更多
Mars is not only our nearby but also the most Earth-like planetary neighbor.Scientific exploration of Mars is thus of crucial value to our understanding of the solar system.The existence of abundant evidence for the f...Mars is not only our nearby but also the most Earth-like planetary neighbor.Scientific exploration of Mars is thus of crucial value to our understanding of the solar system.The existence of abundant evidence for the former presence of water on Mars demands further exploration for signs of life on our sister planet,and investigations that could shed light on conditions favorable to the origin of life.For nearly 60 years,humans have conducted orbitally-based remote sensing and in-situ surface exploration of Mars,leading to many significant scientific discoveries.But much remains to be done before we can be sure that we truly and fully understand Mars.Key research topics include the history of water on Mars and how that history relates to the planet’s habitable environment-past,present,and future;the distribution and evolution of waterbearing and evaporative salt minerals on the planet’s surface;the history of volcanic activity on Mars;the Martian magnetic field and its effect on the escape of water and atmosphere from the planet;interactions between the solar wind and the Martian atmosphere and ionosphere;atmospheric characteristics and climate change on Mars;and so on(Li CL et al.,2018;Liu JJ et al.,2018).Based on the above scientific questions about life,climate,and geology on Mars,the international planetary science community has formulated ambitious Mars exploration programs.展开更多
Ganzi Tibetan Autonomous Prefecture(hereafter referred to as Ganzi),Sichuan Province,China,is situated at the southeastern edge of the Qinghai-Tibet Plateau,adjacent to the Sichuan Basin.The region has a high-elevatio...Ganzi Tibetan Autonomous Prefecture(hereafter referred to as Ganzi),Sichuan Province,China,is situated at the southeastern edge of the Qinghai-Tibet Plateau,adjacent to the Sichuan Basin.The region has a high-elevation mountainous terrain covered by dense forests.On March 15,2024,awildfire broke out in Ganzi due to hot work.展开更多
The evolution of cancer therapies has highlighted the limitations of traditional chemotherapy,particularly its lack of specificity and off-target toxicities,driving the development of targeted treatments like small mo...The evolution of cancer therapies has highlighted the limitations of traditional chemotherapy,particularly its lack of specificity and off-target toxicities,driving the development of targeted treatments like small molecule-drug conjugates(SMDCs).SMDCs offer distinct advantages over antibody-drug conjugates(ADCs),including simpler synthesis,lower production costs,and improved solid tumor penetration due to their smaller size.However,challenges remain,such as a limited variety of targeting ligands and the complexity of optimizing selectivity and efficacy within the tumor microenvironment.This review focuses on key aspects such as mechanisms of action,biomarker selection,and the optimization of each component of SMDCs.It also covers SMDCs that have been approved or are currently under active clinical trials,while providing insights into future developments in this promising field of targeted cancer therapies.展开更多
Antibody-drug conjugates(ADCs),which combine the advantages of monoclonal antibodies with precise targeting and payloads with efficient killing,show great clinical therapeutic value.The ADCs’payloads play a key role ...Antibody-drug conjugates(ADCs),which combine the advantages of monoclonal antibodies with precise targeting and payloads with efficient killing,show great clinical therapeutic value.The ADCs’payloads play a key role in determining the efficacy of ADC drugs and thus have attracted great attention in the field.An ideal ADC payload should possess sufficient toxicity,low immunogenicity,high stability,and modifiable functional groups.Common ADC payloads include tubulin inhibitors and DNA damaging agents,with tubulin inhibitors accounting for more than half of the ADC drugs in clinical development.However,due to clinical limitations of traditional ADC payloads,such as inadequate efficacy and the development of acquired drug resistance,novel highly efficient payloads with diverse targets and reduced side effects are being developed.This perspective summarizes the recent research advances of traditional and novel ADC payloads with main focuses on the structure-activity relationship studies,co-crystal structures,and designing strategies,and further discusses the future research directions of ADC payloads.This review also aims to provide valuable references and future directions for the development of novel ADC payloads that will have high efficacy,low toxicity,adequate stability,and abilities to overcome drug resistance.展开更多
This study aimed to evaluate the wake effect on the electric field detector(EFD) onboard the China Seismo-Electromagnetic Satellite(CSES-01). Through a series of experiments and analyses, we confirmed that the disturb...This study aimed to evaluate the wake effect on the electric field detector(EFD) onboard the China Seismo-Electromagnetic Satellite(CSES-01). Through a series of experiments and analyses, we confirmed that the disturbance phenomenon from probe B of the EFD is not caused by the boom layout. To validate and determine whether it is influenced by the wake effect, we conducted two experiments. In the first experiment, the entire satellite platform underwent a 90° counterclockwise yaw maneuver to allow probe B to avoid the plasma wake region. We then verified whether the disturbance was improved. In the second experiment, the satellite platform performed a 180° counterclockwise yaw maneuver, positioning probe B on the ram side of the satellite and completely avoiding all satellite wakes. The plasma wake effect of the satellite did not significantly influence the spherical probes of the EFD because the measurement accuracy stayed relatively stable under the two experiments, despite the observed abnormalities in the operating state of spherical probe B. This consistency in performance is important for electric field detection missions because the spatial electric field vector data obtained from these probes continue to effectively reflect information on spatial electromagnetic disturbances. These two experimental results showed that probe B consistently exhibited data jump phenomena under various maneuver states, whereas probes A, C, and D did not display such phenomena in any maneuver state.展开更多
About this issue:Radar astronomy is a science that utilizes radar electromagnetic waves to study celestial bodies within and beyond the solar system,focusing mainly on planets,satellites and small bodies such as the M...About this issue:Radar astronomy is a science that utilizes radar electromagnetic waves to study celestial bodies within and beyond the solar system,focusing mainly on planets,satellites and small bodies such as the Moon,Mars,Venus and Saturn.Through radar electromagnetic wave detection,we are able to gain an in-depth understanding of these celestial bodies'internal structures,composition,distribution of water resources,magnetic fields,atmospheres,and other physical properties.This is of great significance for human beings to find a habitable environment in the solar system.At present,the observation methods of radar astronomy mainly rely on ground-based radio telescopes that actively emit electromagnetic waves.In recent years,with the continuous advancement of international deep space exploration,in-situ radar detection technology has gradually become an indispensable new tool for lunar and planetary radar astronomical observations.For example,China's Chang'e3,4,5 and 6 missions,as well as the Tianwen-1 mission to Mars and the United States'Perseverance rover,are equipped with radar payloads.These deep space exploration missions have expanded radar astronomy techniques to lunar and planetary surface observations,greatly enriching and promoting the scientific content and development of radar astronomy.For this reason,the editorial office invited Dr.Chunyu Ding from Shenzhen University and Dr.Yan Su from the National Astronomical Observatories,Chinese Academy of Sciences to co edit a special issue of radar astronomy.展开更多
The rocket sled system is not only a high-speed dynamic ground test system,but also one of the future aerospace horizontal launch schemes.The winged load,as a common type of payload,has greater vibration and noise int...The rocket sled system is not only a high-speed dynamic ground test system,but also one of the future aerospace horizontal launch schemes.The winged load,as a common type of payload,has greater vibration and noise intensity than the wingless load.Due to the severe aerodynamic instability prior to separation,the head-up or head-down phenomena are more evident and the test accuracy significantly decreases.The high-precision computer fluid dynamics and aeroacoustic analysis are employed to explore the multifield coupling mechanism of a rocket sled with the winged payload in the wide speed range(Ma=0.5–2).The results show that as the incoming velocity increases,the cone angle of the shock wave of the rocket sled decreases,the shock pressure increases quickly,and the vortex between the slippers splits and gradually shrinks in size.The velocity of the rocket sled exerts little influence on the modal resonance frequency.The wing has a significant impact on aerodynamic noise,and as the sound pressure level rises,the propagation direction gradually shifts towards the rear and upper regions of the wing.展开更多
Statistics show that more than 80 applications are installed on each android smartphone.Vulnerability research on Android applications is of critical importance.Recently,academic researchers mainly focus on single bug...Statistics show that more than 80 applications are installed on each android smartphone.Vulnerability research on Android applications is of critical importance.Recently,academic researchers mainly focus on single bug patterns,while few of them investigate the relations between multiple bugs.Industrial researchers proposed a series of logic exploit chains leveraging multiple logic bugs.However,there is no general model to evaluate the chaining abilities between bugs.This paper presents a formal model to elucidate the relations between multiple bugs in Android applications.To prove the effectiveness of the model,we design and implement a prototype system named AppChainer.AppChainer automatically identifies attack surfaces of Android applications and investigates whether the payloads entering these attack surfaces are“chainable”.Experimental results on 2138 popular Android applications show that AppChainer is effective in identifying and chaining attacker-controllable payloads.It identifies 14467 chainable payloads and constructs 5458 chains both inside a single application and among various applications.The time cost and resource consumption of AppChainer are also acceptable.For each application,the average analysis time is 317 s,and the average memory consumed is 2368 MB.Compared with the most relevant work Jandroid,the experiment results on our custom DroidChainBench show that AppChainer outperforms Jandroid at the precision rate and performs equally with Jandroid at the recall rate.展开更多
Most viruses and transposons serve as effective carriers for the introduction of foreign DNA up to 11 kb into vertebrate genomes.However,their activity markedly diminishes with payloads exceeding 11 kb.Expanding the p...Most viruses and transposons serve as effective carriers for the introduction of foreign DNA up to 11 kb into vertebrate genomes.However,their activity markedly diminishes with payloads exceeding 11 kb.Expanding the payload capacity of transposons could facilitate more sophisticated cargo designs,improving the regulation of expression and minimizing mutagenic risks associated with molecular therapeutics,metabolic engineering,and transgenic animal production.In this study,we improved the Tol2 transposon by increasing protein expression levels using a translational enhancer(QBI SP163,ST)and enhanced the nuclear targeting ability using the nuclear localization protein H2B(SHT).The modified Tol2 and ST transposon efficiently integrated large DNA cargos into human cell cultures(H1299),comparable to the well-established super PiggyBac system.Furthermore,mRNA from ST and SHT showed a significant increase in transgene delivery efficiency of large DNA payloads(8 kb,14 kb,and 24 kb)into zebrafish(Danio rerio).This study presents a modified Tol2 transposon as an enhanced nonviral vector for the delivery of large DNA payloads in transgenic applications.展开更多
The electro-optical payloads on mobile platforms generally suffer undesirable vibrations generated by maneuvers and turbulence.These vibrations are in six degrees of freedom and cause line-of-sight jitters,resulting i...The electro-optical payloads on mobile platforms generally suffer undesirable vibrations generated by maneuvers and turbulence.These vibrations are in six degrees of freedom and cause line-of-sight jitters,resulting in image blurring and loss of tracking accuracy.In this paper,a Hexapod Vibration Isolation System(HVIS)is proposed and optimized to solve this problem.The optimization aims to centralize and minimize the natural frequencies of HVIS,for expanding the vibration isolation bandwidth and improving the vibration isolation in the higher frequency band.Considering that the design space for HVIS is limited and interfered with the frames of the mobile platform,a non-collision algorithm is proposed and applied in the optimization to obtain the feasible optimal design.The optimization result shows that the natural frequency bandwidth has been reduced by 42.9%,and the maximum natural frequency is reduced by 30.2%.The prototypes of initial and optimal designs are manufactured and tested.Both simulated and experimental results demonstrate the validity of the optimization,and the optimal design provides a maximum of 15 dB more isolation in rotation direction than the initial design.展开更多
The quasi-zero-stiffness (QZS) vibration isolators are effective in achieving low-frequency vibration isolation for a designedpayload, but the isolation effect would be substantially reduced by payload mismatch. To ta...The quasi-zero-stiffness (QZS) vibration isolators are effective in achieving low-frequency vibration isolation for a designedpayload, but the isolation effect would be substantially reduced by payload mismatch. To tackle such a challenging problem, acompensating QZS (CQZS) vibration isolation system (VIS) is proposed to acquire QZS characteristics under arbitrarypayloads. The dynamic characteristics of the CQZS VIS are analyzed to estimate the performance decline of vibration isolationunder payload mismatch. Moreover, the compensation principle of the CQZS VIS is demonstrated, and then the CQZS VIS isfabricated by combining a passive QZS isolator and a compensation system. Finally, experiments are conducted to evaluate thecompensation capability and vibration isolation performance enhance of the CQZS VIS. It is found that the CQZS VIS is ableto compensate payload mismatch, and thus the QZS characteristic can be regained when the payload deviates from thedesigned one, which enabls the QZS VIS to achieve significant low-frequency vibration isolation under payload mismatch.展开更多
Image steganography is one of the prominent technologies in data hiding standards.Steganographic system performance mostly depends on the embedding strategy.Its goal is to embed strictly confidential information into ...Image steganography is one of the prominent technologies in data hiding standards.Steganographic system performance mostly depends on the embedding strategy.Its goal is to embed strictly confidential information into images without causing perceptible changes in the original image.The randomization strategies in data embedding techniques may utilize random domains,pixels,or region-of-interest for concealing secrets into a cover image,preventing information from being discovered by an attacker.The implementation of an appropriate embedding technique can achieve a fair balance between embedding capability and stego image imperceptibility,but it is challenging.A systematic approach is used with a standard methodology to carry out this study.This review concentrates on the critical examination of several embedding strategies,incorporating experimental results with state-of-the-art methods emphasizing the robustness,security,payload capacity,and visual quality metrics of the stego images.The fundamental ideas of steganography are presented in this work,along with a unique viewpoint that sets it apart from previous works by highlighting research gaps,important problems,and difficulties.Additionally,it offers a discussion of suggested directions for future study to advance and investigate uncharted territory in image steganography.展开更多
Disturbance-Free Payload(DFP)spacecraft can meet the requirements of ultra-high attitude pointing accuracy and stability for future space missions.However,as the main control actuators of DFP spacecraft,Linear Non-Con...Disturbance-Free Payload(DFP)spacecraft can meet the requirements of ultra-high attitude pointing accuracy and stability for future space missions.However,as the main control actuators of DFP spacecraft,Linear Non-Contact Lorentz Actuators(LNCLAs)have control output problems with six-degree-of-freedom coupling and nonlinear effects,which will affect the attitude control performance of DFP spacecraft.To solve this problem,a novel concept for Non-Contact Annular Electromagnetic Stabilized Satellite Platform(NCAESSP)is proposed in this study.The concept is centered on replacing the LNCLAs with a non-contact annular electromagnetic actuator to solve the two problems mentioned above.Furthermore,for the different control requirements of the payload module and the support module of the NCAESSP,a high-precision attitude controller based on the robust model matching method and a dual quaternion-based adaptive sliding mode controller are proposed.Additionally,the simulation results verify the feasibility and effectiveness of the proposed approach.展开更多
Earth’s near space,located in the region between 20 and 100 km above sea level,is characterized by extreme conditions,such as low temperature,low atmospheric pressure,harsh radiation,and extreme dryness.These conditi...Earth’s near space,located in the region between 20 and 100 km above sea level,is characterized by extreme conditions,such as low temperature,low atmospheric pressure,harsh radiation,and extreme dryness.These conditions are analogous to those found on the surface of Mars and in the atmosphere of Venus,making Earth’s near space a unique natural laboratory for astrobiological research.To address essential astrobiological questions,teams from the Chinese Academy of Sciences(CAS)have developed a scientific balloon platform,the CAS Balloon-Borne Astrobiology Platform(CAS-BAP),to study the effects of near space environmental conditions on the biology and survival strategies of representative organisms in this terrestrial analog.Here,we describe the versatile Biological Samples Exposure Payload(BIOSEP)loaded on the CAS-BAP with respect to its structure and function.The primary function of BIOSEP is to expose appropriate biological specimens to the harsh conditions of near space and subsequently return the exposed samples to laboratories for further analysis.Four successful flight missions in near space from 2019 to 2021 have demonstrated the high reliability and efficiency of the payload in communicating between hardware and software units,recording environmental data,exposing sample containers,protecting samples from external contamination,and recovering samples.Understanding the effects of Earth’s near space conditions on biological specimens will provide valuable insights into the survival strategies of organisms in extreme environments and the search for life beyond Earth.The development of BIOSEP and associated biological exposure experiments will enhance our understanding of the potential for life on Mars and the habitability of the atmospheric regions of other planets in the solar system and beyond.展开更多
基金Supported by the National Key Research and Development Program of China(2022YFB3904803)。
文摘The Infrared Hyperspectral Atmospheric SounderⅡ(HIRAS-Ⅱ)is the key equipment on FengYun-3E(FY-3E)satellite,which can realize vertical atmospheric detection,featuring hyper spectral,high sensitivity and high precision.To ensure its accuracy of detection,it is necessary to correlate their thermal models to in-orbit da⁃ta.In this work,an investigation of intelligent correlation method named Intelligent Correlation Platform for Ther⁃mal Model(ICP-TM)was established,the advanced Kriging surrogate model and efficient adaptive region opti⁃mization algorithm were introduced.After the correlation with this method for FY-3E/HIRAS-Ⅱ,the results indi⁃cate that compared with the data in orbit,the error of the thermal model has decreased from 5 K to within±1 K in cold case(10℃).Then,the correlated model is validated in hot case(20℃),and the correlated model exhibits good universality.This correlation precision is also much superiors to the general ones like 3 K in other similar lit⁃erature.Furthermore,the process is finished in 8 days using ICP-TM,the efficiency is much better than 3 months based on manual.The results show that the proposed approach significantly enhances the accuracy and efficiency of thermal model,this contributes to the precise thermal control of subsequent infrared optical payloads.
文摘Large unmanned underwater vehicles can carry big payloads for varied missions and it is desirable for them to possess an upright orientation during payload release.Their attitude can hardly be maintained during and after the phase of payload release.Releasing a payload from the vehicle induces uncertainties not only in rigid-body parameters,e.g,the moment of inertia tensor due to the varying distribution of the masses on board the vehicle,but also in the hydrodynamic derivatives due to the vehicle’s varying geometric profile.A nonlinear attitude stabilizer that is robust to these time-varying model uncertainties is proposed in this paper.Stability is guaranteed via Lyapunov stability theory.The simulation results verify the effectiveness of the proposed approach.
基金supported by the National Natural Science Foundation of China(No.91016017)the Funding of Jiangsu Innovation Program for Graduate Education (No. CXZZ12_0160)+1 种基金the Natural Science Foundation of Jiangsu Province of China(No.BK20130234)the Changzhou Sci.& Tech.Program (CE20145056)
文摘A robust attitude control methodology is proposed for satellite system with double rotary payloads. The dynamic model is built by the Newton-Euler method and then the dynamic interconneetion between satellite＇s main body and payloads is described precisely. A nonlinear disturbance observer is designed for satellite＇s main body to estimate disturbance torque acted by motion of payloads. Meanwhile, the adaptive fast nonsingular terminal sliding-mode attitude stabilization controller is proposed for satellite＇s main body to quicken convergence speed of state variables. Similarly, the adaptive fast nonsingular terminal sliding-mode attitude maneuver controller is designed for each payload to weaken the disturbance effect of motion of satellite＇s main body. Simulation results verify the effectiveness of the proposed method.
基金Supported by the Major Program of the National Science Foundation of China(41590851)the Beijing Municipal Science and Technology Commission(Z181100002918003)。
文摘China’s first Mars exploration mission is scheduled to be launched in 2020.It aims not only to conduct global and comprehensive exploration of Mars by use of an orbiter but also to carry out in situ observation of key sites on Mars with a rover.This mission focuses on the following studies:topography,geomorphology,geological structure,soil characteristics,water-ice distribution,material composition,atmosphere and ionosphere,surface climate,environmental characteristics,Mars internal structure,and Martian magnetic field.It is comprised of an orbiter,a lander,and a rover equipped with 13 scientific payloads.This article will give an introduction to the mission including mission plan,scientific objectives,scientific payloads,and its recent development progress.
文摘In this paper, robust control problem is addressed for quad-rotor delivering unknown time-varying payloads. Firstly, the model of a quad-rotor carrying payloads is built. Dynamics of the payloads are treated as disturbances and added into the model of the quad-rotor. Secondly, to enhance system robust-ness, the extended state observer (ESO) is applied to estimate the disturbances from the payloads for feedback compensation. Then a type of predictive controller targeting multiple-input-multiple-output (MIMO) system is developed to degrade the influences caused by sudden changes from load-ing/dropping of the payloads. Finally, by making comparison with the con-ventional cascade proportional-integral-derivative (CPID) and the sliding mode control (SMC) approaches, superiority of the scheme developed is va-lidated. The simulation results indicate that the CPID method shows poor performance on attitude stabilization and the SMC shows input chattering phenomenon even it can achieve satisfied control performances.
文摘Mars is not only our nearby but also the most Earth-like planetary neighbor.Scientific exploration of Mars is thus of crucial value to our understanding of the solar system.The existence of abundant evidence for the former presence of water on Mars demands further exploration for signs of life on our sister planet,and investigations that could shed light on conditions favorable to the origin of life.For nearly 60 years,humans have conducted orbitally-based remote sensing and in-situ surface exploration of Mars,leading to many significant scientific discoveries.But much remains to be done before we can be sure that we truly and fully understand Mars.Key research topics include the history of water on Mars and how that history relates to the planet’s habitable environment-past,present,and future;the distribution and evolution of waterbearing and evaporative salt minerals on the planet’s surface;the history of volcanic activity on Mars;the Martian magnetic field and its effect on the escape of water and atmosphere from the planet;interactions between the solar wind and the Martian atmosphere and ionosphere;atmospheric characteristics and climate change on Mars;and so on(Li CL et al.,2018;Liu JJ et al.,2018).Based on the above scientific questions about life,climate,and geology on Mars,the international planetary science community has formulated ambitious Mars exploration programs.
基金supported by the Space Technologies for Sustainable Development Goals International Partnership Program of the Chinese Academy of Sciences for Big Science(313GJHZ2022040BS)the SDG Report Sub-Project of International Research Center of Big Data for Sustainable Development Goals(CBAS)(CBAS2024SDG009).
文摘Ganzi Tibetan Autonomous Prefecture(hereafter referred to as Ganzi),Sichuan Province,China,is situated at the southeastern edge of the Qinghai-Tibet Plateau,adjacent to the Sichuan Basin.The region has a high-elevation mountainous terrain covered by dense forests.On March 15,2024,awildfire broke out in Ganzi due to hot work.
基金the financial support from the National Natural Science Foundation of China(Nos.82473781,82173652 and 81872728)the Natural Science Foundation of Jiangsu Province(No.BK20221522)Support from Jiangsu“333 High Level Talents Cultivation”Leading Talents(No.2022–3–16–203)。
文摘The evolution of cancer therapies has highlighted the limitations of traditional chemotherapy,particularly its lack of specificity and off-target toxicities,driving the development of targeted treatments like small molecule-drug conjugates(SMDCs).SMDCs offer distinct advantages over antibody-drug conjugates(ADCs),including simpler synthesis,lower production costs,and improved solid tumor penetration due to their smaller size.However,challenges remain,such as a limited variety of targeting ligands and the complexity of optimizing selectivity and efficacy within the tumor microenvironment.This review focuses on key aspects such as mechanisms of action,biomarker selection,and the optimization of each component of SMDCs.It also covers SMDCs that have been approved or are currently under active clinical trials,while providing insights into future developments in this promising field of targeted cancer therapies.
基金provided by the National Natural Science Foundation of China(82073318)the Fundamental Research Funds for the Central Universities(SCU2022D025,0082604151345,China)+1 种基金Sichuan Science and Technology Program Projects(2019YFS0003,China)to Yuxi Wangprovided by the University of Tennessee College of Pharmacy Drug Discovery Center to Wei Li。
文摘Antibody-drug conjugates(ADCs),which combine the advantages of monoclonal antibodies with precise targeting and payloads with efficient killing,show great clinical therapeutic value.The ADCs’payloads play a key role in determining the efficacy of ADC drugs and thus have attracted great attention in the field.An ideal ADC payload should possess sufficient toxicity,low immunogenicity,high stability,and modifiable functional groups.Common ADC payloads include tubulin inhibitors and DNA damaging agents,with tubulin inhibitors accounting for more than half of the ADC drugs in clinical development.However,due to clinical limitations of traditional ADC payloads,such as inadequate efficacy and the development of acquired drug resistance,novel highly efficient payloads with diverse targets and reduced side effects are being developed.This perspective summarizes the recent research advances of traditional and novel ADC payloads with main focuses on the structure-activity relationship studies,co-crystal structures,and designing strategies,and further discusses the future research directions of ADC payloads.This review also aims to provide valuable references and future directions for the development of novel ADC payloads that will have high efficacy,low toxicity,adequate stability,and abilities to overcome drug resistance.
基金a project funded by the China National Space Administration (CNSA) and China Earthquake Administration (CEA)supported by the National Key R&D Program of Intergovernmental Cooperation in Science and Technology (Grant No. 2023YFE0117300)+3 种基金the International Space Science Institute (ISSI in Bern, Switzerland, and ISSI-BJ in Beijing, China)supporting International Team 23-583 led by Dedalo Marchetti and Essam Ghamrythe Hebei Province Graduate Professional Degree Excellent Teaching Case (Library) Construction Project (Grant No. KCJPZ2023060)the Open Fund for the Key Laboratory of Seismic Disaster Instruments and Monitoring Technology in Hebei Province (Grant No. FZ224104)。
文摘This study aimed to evaluate the wake effect on the electric field detector(EFD) onboard the China Seismo-Electromagnetic Satellite(CSES-01). Through a series of experiments and analyses, we confirmed that the disturbance phenomenon from probe B of the EFD is not caused by the boom layout. To validate and determine whether it is influenced by the wake effect, we conducted two experiments. In the first experiment, the entire satellite platform underwent a 90° counterclockwise yaw maneuver to allow probe B to avoid the plasma wake region. We then verified whether the disturbance was improved. In the second experiment, the satellite platform performed a 180° counterclockwise yaw maneuver, positioning probe B on the ram side of the satellite and completely avoiding all satellite wakes. The plasma wake effect of the satellite did not significantly influence the spherical probes of the EFD because the measurement accuracy stayed relatively stable under the two experiments, despite the observed abnormalities in the operating state of spherical probe B. This consistency in performance is important for electric field detection missions because the spatial electric field vector data obtained from these probes continue to effectively reflect information on spatial electromagnetic disturbances. These two experimental results showed that probe B consistently exhibited data jump phenomena under various maneuver states, whereas probes A, C, and D did not display such phenomena in any maneuver state.
文摘About this issue:Radar astronomy is a science that utilizes radar electromagnetic waves to study celestial bodies within and beyond the solar system,focusing mainly on planets,satellites and small bodies such as the Moon,Mars,Venus and Saturn.Through radar electromagnetic wave detection,we are able to gain an in-depth understanding of these celestial bodies'internal structures,composition,distribution of water resources,magnetic fields,atmospheres,and other physical properties.This is of great significance for human beings to find a habitable environment in the solar system.At present,the observation methods of radar astronomy mainly rely on ground-based radio telescopes that actively emit electromagnetic waves.In recent years,with the continuous advancement of international deep space exploration,in-situ radar detection technology has gradually become an indispensable new tool for lunar and planetary radar astronomical observations.For example,China's Chang'e3,4,5 and 6 missions,as well as the Tianwen-1 mission to Mars and the United States'Perseverance rover,are equipped with radar payloads.These deep space exploration missions have expanded radar astronomy techniques to lunar and planetary surface observations,greatly enriching and promoting the scientific content and development of radar astronomy.For this reason,the editorial office invited Dr.Chunyu Ding from Shenzhen University and Dr.Yan Su from the National Astronomical Observatories,Chinese Academy of Sciences to co edit a special issue of radar astronomy.
基金supported by the National Natural Science Foundation of China(No.12104047)。
文摘The rocket sled system is not only a high-speed dynamic ground test system,but also one of the future aerospace horizontal launch schemes.The winged load,as a common type of payload,has greater vibration and noise intensity than the wingless load.Due to the severe aerodynamic instability prior to separation,the head-up or head-down phenomena are more evident and the test accuracy significantly decreases.The high-precision computer fluid dynamics and aeroacoustic analysis are employed to explore the multifield coupling mechanism of a rocket sled with the winged payload in the wide speed range(Ma=0.5–2).The results show that as the incoming velocity increases,the cone angle of the shock wave of the rocket sled decreases,the shock pressure increases quickly,and the vortex between the slippers splits and gradually shrinks in size.The velocity of the rocket sled exerts little influence on the modal resonance frequency.The wing has a significant impact on aerodynamic noise,and as the sound pressure level rises,the propagation direction gradually shifts towards the rear and upper regions of the wing.
基金This work was supported by the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDC02040100).
文摘Statistics show that more than 80 applications are installed on each android smartphone.Vulnerability research on Android applications is of critical importance.Recently,academic researchers mainly focus on single bug patterns,while few of them investigate the relations between multiple bugs.Industrial researchers proposed a series of logic exploit chains leveraging multiple logic bugs.However,there is no general model to evaluate the chaining abilities between bugs.This paper presents a formal model to elucidate the relations between multiple bugs in Android applications.To prove the effectiveness of the model,we design and implement a prototype system named AppChainer.AppChainer automatically identifies attack surfaces of Android applications and investigates whether the payloads entering these attack surfaces are“chainable”.Experimental results on 2138 popular Android applications show that AppChainer is effective in identifying and chaining attacker-controllable payloads.It identifies 14467 chainable payloads and constructs 5458 chains both inside a single application and among various applications.The time cost and resource consumption of AppChainer are also acceptable.For each application,the average analysis time is 317 s,and the average memory consumed is 2368 MB.Compared with the most relevant work Jandroid,the experiment results on our custom DroidChainBench show that AppChainer outperforms Jandroid at the precision rate and performs equally with Jandroid at the recall rate.
基金supported by the National Science and Technology Innovation 2030 Major Projects(2021ZD0202200)National Natural Science Foundation of China(32171090,81970264)+1 种基金Shanghai Science and Technology Commission(21ZR1482600)2023 Youth Innovation Promotion Association CAS。
文摘Most viruses and transposons serve as effective carriers for the introduction of foreign DNA up to 11 kb into vertebrate genomes.However,their activity markedly diminishes with payloads exceeding 11 kb.Expanding the payload capacity of transposons could facilitate more sophisticated cargo designs,improving the regulation of expression and minimizing mutagenic risks associated with molecular therapeutics,metabolic engineering,and transgenic animal production.In this study,we improved the Tol2 transposon by increasing protein expression levels using a translational enhancer(QBI SP163,ST)and enhanced the nuclear targeting ability using the nuclear localization protein H2B(SHT).The modified Tol2 and ST transposon efficiently integrated large DNA cargos into human cell cultures(H1299),comparable to the well-established super PiggyBac system.Furthermore,mRNA from ST and SHT showed a significant increase in transgene delivery efficiency of large DNA payloads(8 kb,14 kb,and 24 kb)into zebrafish(Danio rerio).This study presents a modified Tol2 transposon as an enhanced nonviral vector for the delivery of large DNA payloads in transgenic applications.
基金supported by the National Key R&D Program of China(No.2021YFA1003503)。
文摘The electro-optical payloads on mobile platforms generally suffer undesirable vibrations generated by maneuvers and turbulence.These vibrations are in six degrees of freedom and cause line-of-sight jitters,resulting in image blurring and loss of tracking accuracy.In this paper,a Hexapod Vibration Isolation System(HVIS)is proposed and optimized to solve this problem.The optimization aims to centralize and minimize the natural frequencies of HVIS,for expanding the vibration isolation bandwidth and improving the vibration isolation in the higher frequency band.Considering that the design space for HVIS is limited and interfered with the frames of the mobile platform,a non-collision algorithm is proposed and applied in the optimization to obtain the feasible optimal design.The optimization result shows that the natural frequency bandwidth has been reduced by 42.9%,and the maximum natural frequency is reduced by 30.2%.The prototypes of initial and optimal designs are manufactured and tested.Both simulated and experimental results demonstrate the validity of the optimization,and the optimal design provides a maximum of 15 dB more isolation in rotation direction than the initial design.
基金supported by the National Natural Science Foundation of China(Grant Nos.12302003,12272129,and 12122206)Hong Kong Scholars Program(Grant No.XJ2022012).
文摘The quasi-zero-stiffness (QZS) vibration isolators are effective in achieving low-frequency vibration isolation for a designedpayload, but the isolation effect would be substantially reduced by payload mismatch. To tackle such a challenging problem, acompensating QZS (CQZS) vibration isolation system (VIS) is proposed to acquire QZS characteristics under arbitrarypayloads. The dynamic characteristics of the CQZS VIS are analyzed to estimate the performance decline of vibration isolationunder payload mismatch. Moreover, the compensation principle of the CQZS VIS is demonstrated, and then the CQZS VIS isfabricated by combining a passive QZS isolator and a compensation system. Finally, experiments are conducted to evaluate thecompensation capability and vibration isolation performance enhance of the CQZS VIS. It is found that the CQZS VIS is ableto compensate payload mismatch, and thus the QZS characteristic can be regained when the payload deviates from thedesigned one, which enabls the QZS VIS to achieve significant low-frequency vibration isolation under payload mismatch.
基金This research was funded by the Ministry of Higher Education(MOHE)through Fundamental Research Grant Scheme(FRGS)under the Grand Number FRGS/1/2020/ICT01/UK M/02/4,and University Kebangsaan Malaysia for open access publication.
文摘Image steganography is one of the prominent technologies in data hiding standards.Steganographic system performance mostly depends on the embedding strategy.Its goal is to embed strictly confidential information into images without causing perceptible changes in the original image.The randomization strategies in data embedding techniques may utilize random domains,pixels,or region-of-interest for concealing secrets into a cover image,preventing information from being discovered by an attacker.The implementation of an appropriate embedding technique can achieve a fair balance between embedding capability and stego image imperceptibility,but it is challenging.A systematic approach is used with a standard methodology to carry out this study.This review concentrates on the critical examination of several embedding strategies,incorporating experimental results with state-of-the-art methods emphasizing the robustness,security,payload capacity,and visual quality metrics of the stego images.The fundamental ideas of steganography are presented in this work,along with a unique viewpoint that sets it apart from previous works by highlighting research gaps,important problems,and difficulties.Additionally,it offers a discussion of suggested directions for future study to advance and investigate uncharted territory in image steganography.
基金co-supported by the National Natural Science Foundation of China(No.12172168)。
文摘Disturbance-Free Payload(DFP)spacecraft can meet the requirements of ultra-high attitude pointing accuracy and stability for future space missions.However,as the main control actuators of DFP spacecraft,Linear Non-Contact Lorentz Actuators(LNCLAs)have control output problems with six-degree-of-freedom coupling and nonlinear effects,which will affect the attitude control performance of DFP spacecraft.To solve this problem,a novel concept for Non-Contact Annular Electromagnetic Stabilized Satellite Platform(NCAESSP)is proposed in this study.The concept is centered on replacing the LNCLAs with a non-contact annular electromagnetic actuator to solve the two problems mentioned above.Furthermore,for the different control requirements of the payload module and the support module of the NCAESSP,a high-precision attitude controller based on the robust model matching method and a dual quaternion-based adaptive sliding mode controller are proposed.Additionally,the simulation results verify the feasibility and effectiveness of the proposed approach.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA17010505)
文摘Earth’s near space,located in the region between 20 and 100 km above sea level,is characterized by extreme conditions,such as low temperature,low atmospheric pressure,harsh radiation,and extreme dryness.These conditions are analogous to those found on the surface of Mars and in the atmosphere of Venus,making Earth’s near space a unique natural laboratory for astrobiological research.To address essential astrobiological questions,teams from the Chinese Academy of Sciences(CAS)have developed a scientific balloon platform,the CAS Balloon-Borne Astrobiology Platform(CAS-BAP),to study the effects of near space environmental conditions on the biology and survival strategies of representative organisms in this terrestrial analog.Here,we describe the versatile Biological Samples Exposure Payload(BIOSEP)loaded on the CAS-BAP with respect to its structure and function.The primary function of BIOSEP is to expose appropriate biological specimens to the harsh conditions of near space and subsequently return the exposed samples to laboratories for further analysis.Four successful flight missions in near space from 2019 to 2021 have demonstrated the high reliability and efficiency of the payload in communicating between hardware and software units,recording environmental data,exposing sample containers,protecting samples from external contamination,and recovering samples.Understanding the effects of Earth’s near space conditions on biological specimens will provide valuable insights into the survival strategies of organisms in extreme environments and the search for life beyond Earth.The development of BIOSEP and associated biological exposure experiments will enhance our understanding of the potential for life on Mars and the habitability of the atmospheric regions of other planets in the solar system and beyond.
