With the in-depth implementation of sustainable development strategies,hydrogen energy as a clean energy source is receiving increasing attention[1,2].Among the various methods of hydrogen production,the electrocataly...With the in-depth implementation of sustainable development strategies,hydrogen energy as a clean energy source is receiving increasing attention[1,2].Among the various methods of hydrogen production,the electrocatalytic decomposition of abundant seawater into hydrogen utilizing renewable energy has emerged as a green and promising approach.However,natural seawater contains complex components,such as halide ions,which lead to the corrosion of catalysts or the occurrence of competitive side reactions during the electrolysis process[3].展开更多
The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have bee...The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have been verified by static and shock compression experiments.Nevertheless,the dynamic formation processes underlying these phenomena remain insufficiently understood.In combination with a deep learning model,we demonstrate that diamonds form through a three-step process involving dissociation,species separation,and nucleation processes.Under shock conditions of 125 GPa and 4590 K,hydrocarbons decompose to give hydrogen and low-molecular-weight alkanes(CH_(4) and C_(2)H_(6)),which escape from the carbon chains,resulting in C/H species separation.The remaining carbon atoms without C-H bonds accumulate and nucleate to form diamond crystals.The process of diamond growth is associated with a critical nucleus size at which the dynamic energy barrier plays a key role.These dynamic processes of diamond formation provide insight into the establishment of a model for the evolution of ice giant planets.展开更多
Central retinal artery occlusion(CRAO)is an acute ophthalmic emergency,characterized by sudden vision loss due to retinal ischemia in areas corresponding to arterial occlusion sites.Diagnosis primarily relies on fundu...Central retinal artery occlusion(CRAO)is an acute ophthalmic emergency,characterized by sudden vision loss due to retinal ischemia in areas corresponding to arterial occlusion sites.Diagnosis primarily relies on fundus fluorescein angiography(FFA)and optical coherence tomography(OCT),which show delayed retinal artery filling time hours to days after occlusion and increased hyperreflectivity of the inner retina.展开更多
Oxygen-rich porous carbons are promising candidates for the carbon-based cathodes of zinc ion hybrid capacitors(ZIHCs).Potassium activation is a traditional and effective way to prepare oxygen-rich porous carbons.Effi...Oxygen-rich porous carbons are promising candidates for the carbon-based cathodes of zinc ion hybrid capacitors(ZIHCs).Potassium activation is a traditional and effective way to prepare oxygen-rich porous carbons.Efficient potassium activation is the key to develop high-performance oxygen-rich porous carbon cathodes.Herein,the alkali lignin,extracted from eucalyptus wood by geopolymer-assisted low-alkali pretreatment,is used to prepare oxygen-rich lignin-derived porous carbons(OLPCs)through KOH activation and K_(2)CO_(3)activation at 700-900℃.KOH activation constructs a hierarchical micro-mesoporous structure,while K_(2)CO_(3)activation constructs a microporous structure.Furthermore,K_(2)CO_(3)activation could more efficiently construct active oxygen(C=O)species than KOH activation.The OLPCs prepared by KOH/K_(2)CO_(3)activations at 800℃show the highest microporosity(78.4/87.7%)and C=O content(5.3/8.0 at.%).Due to that C=O and micropore adsorb zinc ions,the OLPCs prepared by K_(2)CO_(3)activation at 800℃with higher C=O content and microporosity deliver superior capacitive performance(256 F g^(-1)at 0.1 A g^(-1))than that by KOH activation at 800℃(224 F g^(-1)at 0.1 A g^(-1)),and excellent cycling stability.This work provides a new insight into the sustainable preparation of oxygenrich porous carbon cathodes through efficient potassium activation for ZIHCs.展开更多
Balancing CO_(2) emission reduction with enhanced gas recovery in carbonate reservoirs remains a key challenge in subsurface energy engineering.This study focuses on the Maokou Formation gas reservoir in the Wolonghe ...Balancing CO_(2) emission reduction with enhanced gas recovery in carbonate reservoirs remains a key challenge in subsurface energy engineering.This study focuses on the Maokou Formation gas reservoir in the Wolonghe Gas Field,Sichuan Basin,and employs a mechanistic model integrated with numerical simulations that couple CO_(2)–water–rock geochemical interactions to systematically explore the principal engineering and chemical factors governing Carbon Capture,Utilization,and Storage–Enhanced Gas Recovery(CCUS–EGR).The analysis reveals that both the injection–production ratio and gas injection rate exhibit optimal ranges.Maximum gas output under single-parameter variation occurs at an injection–production ratio of 0.7 and an injection rate of 130,000 m3/d,while coordinated optimization of both parameters is essential to achieve the highest production enhancement.Excessively high injection–production ratios,however,may induce gas channeling and reduce the ultimate recovery factor.Chemical composition of the injected gas also strongly influences recovery.In the heterogeneous carbonate reservoir considered,a CO_(2)–N2 mixed gas mitigates gravity segregation due to its lower density,expanding sweep efficiency and improving overall gas recovery compared to pure CO_(2) injection.CO_(2)–water–rock reactions further modify reservoir properties.Near the injection well,acidic dissolution enhances porosity,whereas near the production well,a dynamic interplay of ion migration,pressure–temperature variations,and secondary mineral precipitation produces complex porosity evolution.Initial precipitation reduces porosity,while subsequent acidic dissolution partially restores it,creating a heterogeneous and time-dependent porosity profile.展开更多
The Optimal Management of Antithrombotic and Thrombolytic Agents-5(OPTIMA-5)study demonstrated that a single bolus of half the standard dose of recombinant staphylokinase(r-SAK)before primary percutaneous coronary int...The Optimal Management of Antithrombotic and Thrombolytic Agents-5(OPTIMA-5)study demonstrated that a single bolus of half the standard dose of recombinant staphylokinase(r-SAK)before primary percutaneous coronary intervention(PCI)significantly improved the patency of the infarct-related artery in patients with STsegment elevation myocardial infarction(STEMI),who were expected to undergo PCI within 120 min.The present study aimed to investigate the one-year clinical outcomes and the effect of the anti-r-SAK antibodies on a second r-SAK thrombolysis in OPTIMA-5 patients.The clinical outcome measured was major adverse cardiovascular events(MACE)within 360 days.Patients'anti-r-SAK antibody levels were determined on day 90(±7 days),day 180(±7 days),and day 360(±14 days)after thrombolysis,and in vitro r-SAK antibody neutralization experiments were performed to explore an optimal interval for a second r-SAK thrombolysis.Results showed that the MACE incidence was numerically lower in the r-SAK group compared with the normal saline(NS)group(14.0%vs.20.0%,hazard ratio[HR]=0.67,95%confidence interval[CI]:0.34–1.32;log-rank P=0.245).The anti-r-SAK antibody levels in the r-SAK group decreased with time,but remained significantly higher than those in the NS group on day 90(±7 days)(2.96±0.68 vs.0.22±0.53,P<0.001),day 180(±7 days)(2.19±0.74 vs.0.44±0.65,P<0.001),and day 360(±14 days)(1.73±0.97 vs.0.37±0.71,P<0.001).The in vitro anti-r-SAK antibody neutralization experiments demonstrated that the thrombolysis rate decreased exponentially as the antibody titer increased from 1.90 to 2.20(67.80%±14.19%vs.44.32%±21.54%,P<0.0001).Therefore,for STEMI patients who are expected to undergo PCI within 120 min,a single bolus of half-dose rSAK before primary PCI may reduce the one-year MACE risk.The anti-r-SAK antibody persists over one year,and a second r-SAK thrombolysis may not be indicated until at least one year after the first administration,if necessary.展开更多
Focusing on the rehabilitation training of hemiplegia patients,this paper proposes a gait-planning strategy based on a central pattern generator and an adaptive time-delay control scheme that utilizes recursive termin...Focusing on the rehabilitation training of hemiplegia patients,this paper proposes a gait-planning strategy based on a central pattern generator and an adaptive time-delay control scheme that utilizes recursive terminal sliding mode for lower limb rehabilitation exoskeleton robots.The central pattern generator network plans a reference gait trajectory for the affected leg,synchronized with the movement of the healthy leg.The proposed adaptive time-delay control scheme possesses a model-independent property due to the mechanism of time-delay estimation,with adaptive control gains that enhance the resilience against system perturbations and a recursive terminal sliding mode control component to achieve a fast convergence rate.According to the Lyapunov stability criterion,it is proved that the gait trajectory-tracking error is uniformly ultimately bounded.Experiments are conducted on a lower limb exoskeleton experimental platform,and the experimental results demonstrate the effectiveness and superiority of the proposed strategies.展开更多
Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in hu...Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in humans remain unclear,including cell viability,distribution,migration,and fate.Conventional cell tracing methods cannot be used in the clinic.The use of superparamagnetic iron oxide nanoparticles as contrast agents allows for the observation of transplanted cells using magnetic resonance imaging.In 2016,the National Medical Products Administration of China approved a new superparamagnetic iron oxide nanoparticle,Ruicun,for use as a contrast agent in clinical trials.In the present study,an acute hemi-transection spinal cord injury model was established in beagle dogs.The injury was then treated by transplantation of Ruicun-labeled mesenchymal stromal cells.The results indicated that Ruicunlabeled mesenchymal stromal cells repaired damaged spinal cord fibers and partially restored neurological function in animals with acute spinal cord injury.T2*-weighted imaging revealed low signal areas on both sides of the injured spinal cord.The results of quantitative susceptibility mapping with ultrashort echo time sequences indicated that Ruicun-labeled mesenchymal stromal cells persisted stably within the injured spinal cord for over 4 weeks.These findings suggest that magnetic resonance imaging has the potential to effectively track the migration of Ruicun-labeled mesenchymal stromal cells and assess their ability to repair spinal cord injury.展开更多
Post-kidney transplant rejection is a critical factor influencing transplant success rates and the survival of transplanted organs.With the rapid advancement of artificial intelligence technologies,machine learning(ML...Post-kidney transplant rejection is a critical factor influencing transplant success rates and the survival of transplanted organs.With the rapid advancement of artificial intelligence technologies,machine learning(ML)has emerged as a powerful data analysis tool,widely applied in the prediction,diagnosis,and mechanistic study of kidney transplant rejection.This mini-review systematically summarizes the recent applications of ML techniques in post-kidney transplant rejection,covering areas such as the construction of predictive models,identification of biomarkers,analysis of pathological images,assessment of immune cell infiltration,and formulation of personalized treatment strategies.By integrating multi-omics data and clinical information,ML has significantly enhanced the accuracy of early rejection diagnosis and the capability for prognostic evaluation,driving the development of precision medicine in the field of kidney transplantation.Furthermore,this article discusses the challenges faced in existing research and potential future directions,providing a theoretical basis and technical references for related studies.展开更多
Dear Editor,Torpedo maculopathy(TM),first described by Roseman and Gass in 1992[1],is a rare congenital unilateral retinal pigment epithelium(RPE)abnormality.The term“torpedo maculopathy”was coined by Daily[2]in 199...Dear Editor,Torpedo maculopathy(TM),first described by Roseman and Gass in 1992[1],is a rare congenital unilateral retinal pigment epithelium(RPE)abnormality.The term“torpedo maculopathy”was coined by Daily[2]in 1993.TM typically spares the foveal center,is asymptomatic,and is often detected incidentally during routine ophthalmic examinations.Through literature search,we did not identify racial or regional differences in TM.It predominantly affects children,with an estimated prevalence of 2 per 100000 in individuals under 16 ages[3].While previous reports have focused on pediatric and adult populations,this study presents four cases of TM in preterm infants.展开更多
Modular truss space deployable antennas are key for future large aperture,high precision antennas,already proven in various in-orbit applications globally.This paper introduces a design method for a tetrahedral basic ...Modular truss space deployable antennas are key for future large aperture,high precision antennas,already proven in various in-orbit applications globally.This paper introduces a design method for a tetrahedral basic unit mechanism with dual height positioning nodes.A parametric model is established,and its DOF are analyzed to confirm the mechanism's validity.The new tetrahedral basic unit mechanism constructed by this method is a single DOF mechanism and can locate different parabolic node heights.In order to further adapt to the parabolic and large aperture requirements of the deployable antenna of the truss,a combination unit and modular unit mechanism are developed based on this tetrahedral unit.The DOF and deployment characteristics of the modular unit mechanism are analyzed and validated through simulations.Various networking methods for the modular units are proposed,followed by a comprehensive performance comparison of different modular truss deployable antenna mechanisms.A prototype model of the modular unit mechanism is also developed,with deployment experiments demonstrating the mechanism's simplicity,low DOF,and large deployment ratio.The findings of this study provide a theoretical and technical basis for the future design and development of truss deployable antenna mechanisms.展开更多
With the continuous advancement of unmanned technology in various application domains,the development and deployment of blind-spot-free panoramic video systems have gained increasing importance.Such systems are partic...With the continuous advancement of unmanned technology in various application domains,the development and deployment of blind-spot-free panoramic video systems have gained increasing importance.Such systems are particularly critical in battlefield environments,where advanced panoramic video processing and wireless communication technologies are essential to enable remote control and autonomous operation of unmanned ground vehicles(UGVs).However,conventional video surveillance systems suffer from several limitations,including limited field of view,high processing latency,low reliability,excessive resource consumption,and significant transmission delays.These shortcomings impede the widespread adoption of UGVs in battlefield settings.To overcome these challenges,this paper proposes a novel multi-channel video capture and stitching system designed for real-time video processing.The system integrates the Speeded-Up Robust Features(SURF)algorithm and the Fast Library for Approximate Nearest Neighbors(FLANN)algorithm to execute essential operations such as feature detection,descriptor computation,image matching,homography estimation,and seamless image fusion.The fused panoramic video is then encoded and assembled to produce a seamless output devoid of stitching artifacts and shadows.Furthermore,H.264 video compression is employed to reduce the data size of the video stream without sacrificing visual quality.Using the Real-Time Streaming Protocol(RTSP),the compressed stream is transmitted efficiently,supporting real-time remote monitoring and control of UGVs in dynamic battlefield environments.Experimental results indicate that the proposed system achieves high stability,flexibility,and low latency.With a wireless link latency of 30 ms,the end-to-end video transmission latency remains around 140 ms,enabling smooth video communication.The system can tolerate packet loss rates(PLR)of up to 20%while maintaining usable video quality(with latency around 200 ms).These properties make it well-suited for mobile communication scenarios demanding high real-time video performance.展开更多
The efficient flotation separation of rare earth elements(REEs)from gangue minerals is crucial in mineral processing.This study synthesized a quaternary ammonium salt ionic liquid collector,tetrabutylammonium salicylh...The efficient flotation separation of rare earth elements(REEs)from gangue minerals is crucial in mineral processing.This study synthesized a quaternary ammonium salt ionic liquid collector,tetrabutylammonium salicylhydroxamate(T-S),and investigated its performance in separating bastnaesite and fluorite.T-S was synthesized from salicylhydroxamic acid(SHA)and tetrabutylammonium chloride(TBAC),and its molecular structure was characterized using Fourier transform infrared(FTIR)spectroscopy.Microflotation tests indicate that T-S outperforms SHA and TBAC in both collecting ability and selectivity for bastnaesite.Adsorption,zeta potential,and infrared spectroscopy measurements reveal that T-S exhibits stronger adsorption on bastnaesite compared to SHA and TBAC.X-ray photoelectron spectroscopy(XPS)and molecular dynamics simulations(MDS)results confirm that chemical adsorption occurs between Ce on the bastnaesite surface and the-C(=O)NHOH groups of T-S.Moreover,the interaction between T-S and the bastnaesite surface is stronger than that with the fluorite surface.This work provides valuable insights for designing ionic liquid collectors for the flotation separation of bastnaesite and fluorite.展开更多
In this paper,a unified terminal sliding mode(UTSM)control method is proposed for second-order nonlinear systems with uncertainties and disturbances.It is seen that the newly defined terminal sliding surface is integr...In this paper,a unified terminal sliding mode(UTSM)control method is proposed for second-order nonlinear systems with uncertainties and disturbances.It is seen that the newly defined terminal sliding surface is integrated with both conventional and fast terminal sliding mode and exhibits design advantages such as a variable exponent,adjustable sliding mode parameters,and chattering-alleviation effect.The inherent dynamic properties of the closed-loop systems with the UTSM control are discussed in detail via the phase plane and Lyapunov stability theory.Both numerical simulations and experimental results show the flexible sliding manifold design,strong robustness against uncertain dynamics,and effective attenuation of chattering phenomenon.展开更多
Enhancing corrosion resistance in cast alloys using straightforward and cost-effective micro-alloying techniques has emerged as a key area of investigation in materials science.The challenge lies in applying this tech...Enhancing corrosion resistance in cast alloys using straightforward and cost-effective micro-alloying techniques has emerged as a key area of investigation in materials science.The challenge lies in applying this technique to further enhance the already excellent properties of CoCrNi medium-entropy alloys(MEAs)for casting applications.A micro-alloying approach was proposed to improve the corrosion resistance of as-cast CoCrNi MEAs by incorporating cerium(Ce).The corrosion resistance of CoCrNi MEAs firstly increases and then decreases as the Ce content increases in a 3.5wt.%NaCl solution.At a Ce content of 0.02at.%,the passivation current density reaches its minimum value(26.383μA·cm^(-2)),while the breakdown potential reaches its maximum(0.471 V_(SCE)),imparting exceptional corrosion resistance.The results indicate that the enhanced corrosion resistance is primary due to Ce micro-alloying,which affects inclusions by forming a non-conductive precipitated phase and modifying the passivation film.Ce micro-alloying presents a promising strategy for enhancing the corrosion resistance of as-cast CoCrNi MEAs.展开更多
Understanding the complex deformation mechanisms of non-equimolar multi-principal element alloys(MPEAs)requires high-fidelity atomic-scale simulations.This study develops a deep potential(DP)model to enable molecular ...Understanding the complex deformation mechanisms of non-equimolar multi-principal element alloys(MPEAs)requires high-fidelity atomic-scale simulations.This study develops a deep potential(DP)model to enable molecular dynamics simulations of the Ta_(0.4)Ti_(2)Zr(Ta_(0.4))alloy.Monte Carlo simulations using this potential reveal Ta atom precipitation in the Ta_(0.4)alloy.Under uniaxial tensile loading along the[100]direction in the NPT ensemble,the alloy undergoes a remarkable sequence of phase transformations:an initial body-centered cubic(BCC_(1))to face-centered cubic(FCC)transformation,followed by a reverse transformation from FCC to a distinct BCC phase(BCC_(2)),and finally a BCC_(2) to hexagonal close-packed(HCP)transformation.Critically,the reverse FCC to BCC_(2) transformation induces significant volume contraction.We demonstrate that the inversely transformed BCC_(2) phase primarily accommodates compressive stress.Concurrently,the reorientation of BCC_(2) crystals contributes substantially to the observed high strain hardening.These simulations provide atomic-scale insights into the dynamic structural evolution,sequential phase transformations,and stress partitioning during deformation of the Ta_(0.4)alloy.The developed DP model and the revealed mechanisms offer fundamental theoretical guidance for accelerating the design of high-performance MPEAs.展开更多
The healing of critical-sized bone defects(CSD)remains a challenge in orthopedic medicine.In recent years,scaffolds with sophisticated microstructures fabricated by the emerging three-dimensional(3D)printing technolog...The healing of critical-sized bone defects(CSD)remains a challenge in orthopedic medicine.In recent years,scaffolds with sophisticated microstructures fabricated by the emerging three-dimensional(3D)printing technology have lighted up the treatment of the CSD due to the elaborate microenvironments and support they may build.Here,we established a magnesium oxide-reinforced 3D-printed biocompos-ite scaffold to investigate the effect of magnesium-enriched 3D microenvironment on CSD repairing.The composite was prepared using a biodegradable polymer matrix,polycaprolactone(PCL),and the disper-sion phase,magnesium oxide(MgO).With the appropriate surface treatment by saline coupling agent,the MgO dispersed homogeneously in the polymer matrix,leading to enhanced mechanical performance and steady release of magnesium ion(Mg^(2+))for superior cytocompatibility,higher cell viability,advanced osteogenic differentiation,and cell mineralization capabilities in comparison with the pure PCL.The in-vivo femoral implantation and critical-sized cranial bone defect studies demonstrated the importance of the 3D magnesium microenvironment,as a scaffold that released appropriate Mg^(2+) exhibited remarkably increased bone volume,enhanced angiogenesis,and almost recovered CSD after 8-week implantation.Overall,this study suggests that the magnesium-enriched 3D scaffold is a potential candidate for the treatment of CSD in a cell-free therapeutic approach.展开更多
Diffusion bonding of refractory Nb–Si-based alloy was performed with Ni/Al and Ti/Al nanolayers under the condition of 1473 K/30 MPa/60 min.The NbSS/Nb5Si3 in situ composite with the nominal composition of Nb–22 Ti...Diffusion bonding of refractory Nb–Si-based alloy was performed with Ni/Al and Ti/Al nanolayers under the condition of 1473 K/30 MPa/60 min.The NbSS/Nb5Si3 in situ composite with the nominal composition of Nb–22 Ti–16 Si–3 Cr–3 Al–2 Hf was used as the parent material.The joint microstructures were examined by using a scanning electron microscope equipped with an X-ray energy dispersive spectrometer.Shear test was conducted for the bonded joints at room temperature.Within the joint bonded with Ni/Al multilayer,element diffusion occurred between the base metal and the nanolayer,with the reaction products of AlNb2+Ni3 Al,NiAl and AlNi2 Ti phases.The average shear strength was 182 MPa.While using Ti/Al multilayer,the interface mainly consisted of TiAl,(Ti,Nb)Al and(Ti,Nb)2 Al phases,and the corresponding joints exhibited an increased strength of 228 MPa.In this case,the fracture mainly took place in the TiAl phase and presented a typical brittle characteristic.展开更多
The Advanced Space-based Solar Observatory(ASO-S) mission aims to explore the two most spectacular eruptions on the Sun: solar flares and coronal mass ejections(CMEs), and their magnetism.For the study of CMEs, the pa...The Advanced Space-based Solar Observatory(ASO-S) mission aims to explore the two most spectacular eruptions on the Sun: solar flares and coronal mass ejections(CMEs), and their magnetism.For the study of CMEs, the payload Lyman-alpha Solar Telescope(LST) has been proposed. It includes a traditional white-light coronagraph and a Lyman-alpha coronagraph which opens a new window to CME observations. Polarization measurements taken by white-light coronagraphs are crucial for deriving fundamental physical parameters of CMEs. To make such measurements, there are two options for a Stokes polarimeter which have been applied by existing white-light coronagraphs for space missions. One uses a single or triple linear polarizer, the other involves both a half-wave plate and a linear polarizer. We find that the former option is subject to less uncertainty in the derived Stokes vector propagating from detector noise.The latter option involves two plates which are prone to internal reflections and may have a reduced transmission factor. Therefore, the former option is adopted as our Stokes polarimeter scheme for LST. Based on the parameters of the intended linear polarizer(s) colorPol provided by CODIXX and the half-wave plate 2-APW-L2-012 C by Altechna, it is further shown that the imperfect maximum transmittance of the polarizer significantly increases the variance amplification of Stokes vector by at least about 50% when compared with the ideal case. The relative errors of Stokes vector caused by the imperfection of colorPol polarizer and the uncertainty due to the polarizer assembly in the telescope are estimated to be about 5%. Among the considered parameters, we find that the dominant error comes from the uncertainty in the maximum transmittance of the polarizer.展开更多
Atmospheric pressure plasma jet(APPJ)was used to clean nitrogen-containing carbon films(C–N)fabricated by plasma-assisted chemical vapor deposition method employing the plasma surface interaction linear device at Sic...Atmospheric pressure plasma jet(APPJ)was used to clean nitrogen-containing carbon films(C–N)fabricated by plasma-assisted chemical vapor deposition method employing the plasma surface interaction linear device at Sichuan University(SCU-PSI).The properties of the contaminated films on the surface of pristine and He-plasma pre-irradiated tungsten matrix,such as morphology,crystalline structure,element composition and chemical structure were characterized by scanning electron microscopy,grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy.The experimental results revealed that the removal of C–N film with a thickness of tens of microns can be realized through APPJ cleaning regardless of the morphology of the substrates.Similar removal rates of 16.82 and 13.78μm min^(-1)were obtained for C–N films deposited on a smooth pristine W surface and rough fuzz-covered W surface,respectively.This is a remarkable improvement in comparison to the traditional cleaning method.However,slight surface oxidation was found after APPJ cleaning,but the degree of oxidation was acceptable with an oxidation depth increase of only 3.15 nm.Optical emission spectroscopy analysis and mass spectrometry analysis showed that C–N contamination was mainly removed through chemical reaction with reactive oxygen species during APPJ treatment using air as the working gas.These results make APPJ cleaning a potentially effective method for the rapid removal of C–N films from the wall surfaces of fusion devices.展开更多
基金financially supported by the Natural Science Research Start-up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(No.NY223016)Qinglan Project of Jiangsu Province of China2024 Nanjing Science and Technology Innovation Program(No.NJKCZYZZ2024-06)。
文摘With the in-depth implementation of sustainable development strategies,hydrogen energy as a clean energy source is receiving increasing attention[1,2].Among the various methods of hydrogen production,the electrocatalytic decomposition of abundant seawater into hydrogen utilizing renewable energy has emerged as a green and promising approach.However,natural seawater contains complex components,such as halide ions,which lead to the corrosion of catalysts or the occurrence of competitive side reactions during the electrolysis process[3].
基金supported by the National Natural Science Foundation of China(Grant Nos.12534013,12047561,and 12104507)the Science and Technology Innovation Program of Hunan Province(Grant Nos.2025ZYJ001 and 2021RC4026)the National University of Defense Technology Research Fund Project.
文摘The accumulation and circulation of carbon and hydrogen contribute to the chemical evolution of ice giant planets.Species separation and diamond precipitation have been reported in carbon-hydrogen systems and have been verified by static and shock compression experiments.Nevertheless,the dynamic formation processes underlying these phenomena remain insufficiently understood.In combination with a deep learning model,we demonstrate that diamonds form through a three-step process involving dissociation,species separation,and nucleation processes.Under shock conditions of 125 GPa and 4590 K,hydrocarbons decompose to give hydrogen and low-molecular-weight alkanes(CH_(4) and C_(2)H_(6)),which escape from the carbon chains,resulting in C/H species separation.The remaining carbon atoms without C-H bonds accumulate and nucleate to form diamond crystals.The process of diamond growth is associated with a critical nucleus size at which the dynamic energy barrier plays a key role.These dynamic processes of diamond formation provide insight into the establishment of a model for the evolution of ice giant planets.
基金Supported by National Natural Science Foundation of China(No.82070991).
文摘Central retinal artery occlusion(CRAO)is an acute ophthalmic emergency,characterized by sudden vision loss due to retinal ischemia in areas corresponding to arterial occlusion sites.Diagnosis primarily relies on fundus fluorescein angiography(FFA)and optical coherence tomography(OCT),which show delayed retinal artery filling time hours to days after occlusion and increased hyperreflectivity of the inner retina.
基金supported by the National Natural Science Foundation of China(22408061 and 22468005)Program for Introducing High-Level Talents from Guangxi University,and Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology(2023Z014).
文摘Oxygen-rich porous carbons are promising candidates for the carbon-based cathodes of zinc ion hybrid capacitors(ZIHCs).Potassium activation is a traditional and effective way to prepare oxygen-rich porous carbons.Efficient potassium activation is the key to develop high-performance oxygen-rich porous carbon cathodes.Herein,the alkali lignin,extracted from eucalyptus wood by geopolymer-assisted low-alkali pretreatment,is used to prepare oxygen-rich lignin-derived porous carbons(OLPCs)through KOH activation and K_(2)CO_(3)activation at 700-900℃.KOH activation constructs a hierarchical micro-mesoporous structure,while K_(2)CO_(3)activation constructs a microporous structure.Furthermore,K_(2)CO_(3)activation could more efficiently construct active oxygen(C=O)species than KOH activation.The OLPCs prepared by KOH/K_(2)CO_(3)activations at 800℃show the highest microporosity(78.4/87.7%)and C=O content(5.3/8.0 at.%).Due to that C=O and micropore adsorb zinc ions,the OLPCs prepared by K_(2)CO_(3)activation at 800℃with higher C=O content and microporosity deliver superior capacitive performance(256 F g^(-1)at 0.1 A g^(-1))than that by KOH activation at 800℃(224 F g^(-1)at 0.1 A g^(-1)),and excellent cycling stability.This work provides a new insight into the sustainable preparation of oxygenrich porous carbon cathodes through efficient potassium activation for ZIHCs.
基金funded by the National Science Foundation of China(52204033)the Science&Technology Department of Sichuan Province(2024NSFSC0201)Scientific research Project of Petro China Southwest Oil&Gas Field Company(No.2024D112-01-01).
文摘Balancing CO_(2) emission reduction with enhanced gas recovery in carbonate reservoirs remains a key challenge in subsurface energy engineering.This study focuses on the Maokou Formation gas reservoir in the Wolonghe Gas Field,Sichuan Basin,and employs a mechanistic model integrated with numerical simulations that couple CO_(2)–water–rock geochemical interactions to systematically explore the principal engineering and chemical factors governing Carbon Capture,Utilization,and Storage–Enhanced Gas Recovery(CCUS–EGR).The analysis reveals that both the injection–production ratio and gas injection rate exhibit optimal ranges.Maximum gas output under single-parameter variation occurs at an injection–production ratio of 0.7 and an injection rate of 130,000 m3/d,while coordinated optimization of both parameters is essential to achieve the highest production enhancement.Excessively high injection–production ratios,however,may induce gas channeling and reduce the ultimate recovery factor.Chemical composition of the injected gas also strongly influences recovery.In the heterogeneous carbonate reservoir considered,a CO_(2)–N2 mixed gas mitigates gravity segregation due to its lower density,expanding sweep efficiency and improving overall gas recovery compared to pure CO_(2) injection.CO_(2)–water–rock reactions further modify reservoir properties.Near the injection well,acidic dissolution enhances porosity,whereas near the production well,a dynamic interplay of ion migration,pressure–temperature variations,and secondary mineral precipitation produces complex porosity evolution.Initial precipitation reduces porosity,while subsequent acidic dissolution partially restores it,creating a heterogeneous and time-dependent porosity profile.
基金supported by the National Natural Science Funding of China(Grant No.82170351)the Special Fund for Key R&D Plans(Social Development)of Jiangsu Province(Grant No.BE2019754)Kanion Pharmaceutical Group,Lianyungang,Jiangsu,China。
文摘The Optimal Management of Antithrombotic and Thrombolytic Agents-5(OPTIMA-5)study demonstrated that a single bolus of half the standard dose of recombinant staphylokinase(r-SAK)before primary percutaneous coronary intervention(PCI)significantly improved the patency of the infarct-related artery in patients with STsegment elevation myocardial infarction(STEMI),who were expected to undergo PCI within 120 min.The present study aimed to investigate the one-year clinical outcomes and the effect of the anti-r-SAK antibodies on a second r-SAK thrombolysis in OPTIMA-5 patients.The clinical outcome measured was major adverse cardiovascular events(MACE)within 360 days.Patients'anti-r-SAK antibody levels were determined on day 90(±7 days),day 180(±7 days),and day 360(±14 days)after thrombolysis,and in vitro r-SAK antibody neutralization experiments were performed to explore an optimal interval for a second r-SAK thrombolysis.Results showed that the MACE incidence was numerically lower in the r-SAK group compared with the normal saline(NS)group(14.0%vs.20.0%,hazard ratio[HR]=0.67,95%confidence interval[CI]:0.34–1.32;log-rank P=0.245).The anti-r-SAK antibody levels in the r-SAK group decreased with time,but remained significantly higher than those in the NS group on day 90(±7 days)(2.96±0.68 vs.0.22±0.53,P<0.001),day 180(±7 days)(2.19±0.74 vs.0.44±0.65,P<0.001),and day 360(±14 days)(1.73±0.97 vs.0.37±0.71,P<0.001).The in vitro anti-r-SAK antibody neutralization experiments demonstrated that the thrombolysis rate decreased exponentially as the antibody titer increased from 1.90 to 2.20(67.80%±14.19%vs.44.32%±21.54%,P<0.0001).Therefore,for STEMI patients who are expected to undergo PCI within 120 min,a single bolus of half-dose rSAK before primary PCI may reduce the one-year MACE risk.The anti-r-SAK antibody persists over one year,and a second r-SAK thrombolysis may not be indicated until at least one year after the first administration,if necessary.
基金supported by the National Natural Science Foundation of China(62473337,62003305)the Key Research and Development Program of Zhejiang Province(2024C03040,2022C03029)the funding of Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang Province(2023R01006).
文摘Focusing on the rehabilitation training of hemiplegia patients,this paper proposes a gait-planning strategy based on a central pattern generator and an adaptive time-delay control scheme that utilizes recursive terminal sliding mode for lower limb rehabilitation exoskeleton robots.The central pattern generator network plans a reference gait trajectory for the affected leg,synchronized with the movement of the healthy leg.The proposed adaptive time-delay control scheme possesses a model-independent property due to the mechanism of time-delay estimation,with adaptive control gains that enhance the resilience against system perturbations and a recursive terminal sliding mode control component to achieve a fast convergence rate.According to the Lyapunov stability criterion,it is proved that the gait trajectory-tracking error is uniformly ultimately bounded.Experiments are conducted on a lower limb exoskeleton experimental platform,and the experimental results demonstrate the effectiveness and superiority of the proposed strategies.
基金supported by the National Key R&D Program of China,Nos.2017YFA0104302(to NG and XM)and 2017YFA0104304(to BW and ZZ)
文摘Mesenchymal stromal cell transplantation is an effective and promising approach for treating various systemic and diffuse diseases.However,the biological characteristics of transplanted mesenchymal stromal cells in humans remain unclear,including cell viability,distribution,migration,and fate.Conventional cell tracing methods cannot be used in the clinic.The use of superparamagnetic iron oxide nanoparticles as contrast agents allows for the observation of transplanted cells using magnetic resonance imaging.In 2016,the National Medical Products Administration of China approved a new superparamagnetic iron oxide nanoparticle,Ruicun,for use as a contrast agent in clinical trials.In the present study,an acute hemi-transection spinal cord injury model was established in beagle dogs.The injury was then treated by transplantation of Ruicun-labeled mesenchymal stromal cells.The results indicated that Ruicunlabeled mesenchymal stromal cells repaired damaged spinal cord fibers and partially restored neurological function in animals with acute spinal cord injury.T2*-weighted imaging revealed low signal areas on both sides of the injured spinal cord.The results of quantitative susceptibility mapping with ultrashort echo time sequences indicated that Ruicun-labeled mesenchymal stromal cells persisted stably within the injured spinal cord for over 4 weeks.These findings suggest that magnetic resonance imaging has the potential to effectively track the migration of Ruicun-labeled mesenchymal stromal cells and assess their ability to repair spinal cord injury.
文摘Post-kidney transplant rejection is a critical factor influencing transplant success rates and the survival of transplanted organs.With the rapid advancement of artificial intelligence technologies,machine learning(ML)has emerged as a powerful data analysis tool,widely applied in the prediction,diagnosis,and mechanistic study of kidney transplant rejection.This mini-review systematically summarizes the recent applications of ML techniques in post-kidney transplant rejection,covering areas such as the construction of predictive models,identification of biomarkers,analysis of pathological images,assessment of immune cell infiltration,and formulation of personalized treatment strategies.By integrating multi-omics data and clinical information,ML has significantly enhanced the accuracy of early rejection diagnosis and the capability for prognostic evaluation,driving the development of precision medicine in the field of kidney transplantation.Furthermore,this article discusses the challenges faced in existing research and potential future directions,providing a theoretical basis and technical references for related studies.
基金Supported by the National Natural Science Foundation of China(No.82070991).
文摘Dear Editor,Torpedo maculopathy(TM),first described by Roseman and Gass in 1992[1],is a rare congenital unilateral retinal pigment epithelium(RPE)abnormality.The term“torpedo maculopathy”was coined by Daily[2]in 1993.TM typically spares the foveal center,is asymptomatic,and is often detected incidentally during routine ophthalmic examinations.Through literature search,we did not identify racial or regional differences in TM.It predominantly affects children,with an estimated prevalence of 2 per 100000 in individuals under 16 ages[3].While previous reports have focused on pediatric and adult populations,this study presents four cases of TM in preterm infants.
基金sponsored by the National Natural Science Foundation of China(No.52075467)Hebei Province Fund Outstanding Youth Fund Project,China(No.E2024203107)。
文摘Modular truss space deployable antennas are key for future large aperture,high precision antennas,already proven in various in-orbit applications globally.This paper introduces a design method for a tetrahedral basic unit mechanism with dual height positioning nodes.A parametric model is established,and its DOF are analyzed to confirm the mechanism's validity.The new tetrahedral basic unit mechanism constructed by this method is a single DOF mechanism and can locate different parabolic node heights.In order to further adapt to the parabolic and large aperture requirements of the deployable antenna of the truss,a combination unit and modular unit mechanism are developed based on this tetrahedral unit.The DOF and deployment characteristics of the modular unit mechanism are analyzed and validated through simulations.Various networking methods for the modular units are proposed,followed by a comprehensive performance comparison of different modular truss deployable antenna mechanisms.A prototype model of the modular unit mechanism is also developed,with deployment experiments demonstrating the mechanism's simplicity,low DOF,and large deployment ratio.The findings of this study provide a theoretical and technical basis for the future design and development of truss deployable antenna mechanisms.
基金supported by the National Natural Science Foundation of China(Grant No.72334003)the National Key Research and Development Program of China(Grant No.2022YFB2702804)+1 种基金the Shandong Key Research and Development Program(Grant No.2020ZLYS09)the Jinan Program(Grant No.2021GXRC084-2).
文摘With the continuous advancement of unmanned technology in various application domains,the development and deployment of blind-spot-free panoramic video systems have gained increasing importance.Such systems are particularly critical in battlefield environments,where advanced panoramic video processing and wireless communication technologies are essential to enable remote control and autonomous operation of unmanned ground vehicles(UGVs).However,conventional video surveillance systems suffer from several limitations,including limited field of view,high processing latency,low reliability,excessive resource consumption,and significant transmission delays.These shortcomings impede the widespread adoption of UGVs in battlefield settings.To overcome these challenges,this paper proposes a novel multi-channel video capture and stitching system designed for real-time video processing.The system integrates the Speeded-Up Robust Features(SURF)algorithm and the Fast Library for Approximate Nearest Neighbors(FLANN)algorithm to execute essential operations such as feature detection,descriptor computation,image matching,homography estimation,and seamless image fusion.The fused panoramic video is then encoded and assembled to produce a seamless output devoid of stitching artifacts and shadows.Furthermore,H.264 video compression is employed to reduce the data size of the video stream without sacrificing visual quality.Using the Real-Time Streaming Protocol(RTSP),the compressed stream is transmitted efficiently,supporting real-time remote monitoring and control of UGVs in dynamic battlefield environments.Experimental results indicate that the proposed system achieves high stability,flexibility,and low latency.With a wireless link latency of 30 ms,the end-to-end video transmission latency remains around 140 ms,enabling smooth video communication.The system can tolerate packet loss rates(PLR)of up to 20%while maintaining usable video quality(with latency around 200 ms).These properties make it well-suited for mobile communication scenarios demanding high real-time video performance.
基金Project supported by the National Key Research and Development Program of China(2022YFC2905800)National Natural Science Foundation of China(52374276,52274269)+2 种基金Yunnan Fundamental Re search Projects(202401AS070051)the Natural Science Foundation of Hubei Province of China(2024AFD123)Young Elite Scientists Sponsorship Program by CAST(YESS20200276)。
文摘The efficient flotation separation of rare earth elements(REEs)from gangue minerals is crucial in mineral processing.This study synthesized a quaternary ammonium salt ionic liquid collector,tetrabutylammonium salicylhydroxamate(T-S),and investigated its performance in separating bastnaesite and fluorite.T-S was synthesized from salicylhydroxamic acid(SHA)and tetrabutylammonium chloride(TBAC),and its molecular structure was characterized using Fourier transform infrared(FTIR)spectroscopy.Microflotation tests indicate that T-S outperforms SHA and TBAC in both collecting ability and selectivity for bastnaesite.Adsorption,zeta potential,and infrared spectroscopy measurements reveal that T-S exhibits stronger adsorption on bastnaesite compared to SHA and TBAC.X-ray photoelectron spectroscopy(XPS)and molecular dynamics simulations(MDS)results confirm that chemical adsorption occurs between Ce on the bastnaesite surface and the-C(=O)NHOH groups of T-S.Moreover,the interaction between T-S and the bastnaesite surface is stronger than that with the fluorite surface.This work provides valuable insights for designing ionic liquid collectors for the flotation separation of bastnaesite and fluorite.
基金supported by the National Natural Science Foundation of China(62473337,62003305)the Key Research and Development Program of Zhejiang Province(2024C03040,2022C03029)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang Province(2023R01006)。
文摘In this paper,a unified terminal sliding mode(UTSM)control method is proposed for second-order nonlinear systems with uncertainties and disturbances.It is seen that the newly defined terminal sliding surface is integrated with both conventional and fast terminal sliding mode and exhibits design advantages such as a variable exponent,adjustable sliding mode parameters,and chattering-alleviation effect.The inherent dynamic properties of the closed-loop systems with the UTSM control are discussed in detail via the phase plane and Lyapunov stability theory.Both numerical simulations and experimental results show the flexible sliding manifold design,strong robustness against uncertain dynamics,and effective attenuation of chattering phenomenon.
基金financially supported by the Natural Science Foundation of China(52264055)the Natural Science Foundation of Inner Mongolia Autonomous Region(2024MS05038)+4 种基金the Open Project of State Key Laboratory of Advanced Special Steel,the Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(SKLASS 2023-05)the Science and Technology Commission of Shanghai Municipality(19DZ2270200)the Fundamental Research Funds for Inner Mongolia University of Science&Technology(2024QNJS086)the Rare Earth Advanced Materials Technology Innovation Center(0904052404)the Program for Innovative Research Team in Universities of Inner Mongolia Autonomous Region(NMGIRT2401)。
文摘Enhancing corrosion resistance in cast alloys using straightforward and cost-effective micro-alloying techniques has emerged as a key area of investigation in materials science.The challenge lies in applying this technique to further enhance the already excellent properties of CoCrNi medium-entropy alloys(MEAs)for casting applications.A micro-alloying approach was proposed to improve the corrosion resistance of as-cast CoCrNi MEAs by incorporating cerium(Ce).The corrosion resistance of CoCrNi MEAs firstly increases and then decreases as the Ce content increases in a 3.5wt.%NaCl solution.At a Ce content of 0.02at.%,the passivation current density reaches its minimum value(26.383μA·cm^(-2)),while the breakdown potential reaches its maximum(0.471 V_(SCE)),imparting exceptional corrosion resistance.The results indicate that the enhanced corrosion resistance is primary due to Ce micro-alloying,which affects inclusions by forming a non-conductive precipitated phase and modifying the passivation film.Ce micro-alloying presents a promising strategy for enhancing the corrosion resistance of as-cast CoCrNi MEAs.
基金supported by the National University of Defense Technology Research Fund Projectthe National Natural Science Foundation of China(Grant No.12534013)the Science and Technology Innovation Program of Hunan Province(Grant Nos.2025ZYJ001 and 2021RC4026)。
文摘Understanding the complex deformation mechanisms of non-equimolar multi-principal element alloys(MPEAs)requires high-fidelity atomic-scale simulations.This study develops a deep potential(DP)model to enable molecular dynamics simulations of the Ta_(0.4)Ti_(2)Zr(Ta_(0.4))alloy.Monte Carlo simulations using this potential reveal Ta atom precipitation in the Ta_(0.4)alloy.Under uniaxial tensile loading along the[100]direction in the NPT ensemble,the alloy undergoes a remarkable sequence of phase transformations:an initial body-centered cubic(BCC_(1))to face-centered cubic(FCC)transformation,followed by a reverse transformation from FCC to a distinct BCC phase(BCC_(2)),and finally a BCC_(2) to hexagonal close-packed(HCP)transformation.Critically,the reverse FCC to BCC_(2) transformation induces significant volume contraction.We demonstrate that the inversely transformed BCC_(2) phase primarily accommodates compressive stress.Concurrently,the reorientation of BCC_(2) crystals contributes substantially to the observed high strain hardening.These simulations provide atomic-scale insights into the dynamic structural evolution,sequential phase transformations,and stress partitioning during deformation of the Ta_(0.4)alloy.The developed DP model and the revealed mechanisms offer fundamental theoretical guidance for accelerating the design of high-performance MPEAs.
基金The authors would like to thank Li LI and H.Z.Xie for the technical support.This work was financially supported by the National Natural Science Foundation of China(Nos.82002303 and 81702171)the Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515011536,2021A1515220093,2021A1515220086,2019A1515111156,and 2022A1515011815)+7 种基金the Scientific Research Foundation of Peking University Shenzhen hospital(No.KYQD2021064)the Health and Medical Research Fund(No.19180712)the Shenzhen Double Chain Project for Innovation and Development Industry supported by the Bureau of Industry and Information Technology of Shenzhen(No.201806081018272960)the Shenzhen Science and Technology Innovation Committee Projects(Nos.JCYJ20190809182213535 and JSGG20180507183242702)the program from Shanghai Municipal Health Commission(No.201740165)the National Key R&D Program of China(No.2018YFC1105100)the Hong Kong Innovation Technology Fund(Nos.ITS/287/17 and ITS/405/18)the Hong Kong Research Grant Council General Research Fund(No.17214516).
文摘The healing of critical-sized bone defects(CSD)remains a challenge in orthopedic medicine.In recent years,scaffolds with sophisticated microstructures fabricated by the emerging three-dimensional(3D)printing technology have lighted up the treatment of the CSD due to the elaborate microenvironments and support they may build.Here,we established a magnesium oxide-reinforced 3D-printed biocompos-ite scaffold to investigate the effect of magnesium-enriched 3D microenvironment on CSD repairing.The composite was prepared using a biodegradable polymer matrix,polycaprolactone(PCL),and the disper-sion phase,magnesium oxide(MgO).With the appropriate surface treatment by saline coupling agent,the MgO dispersed homogeneously in the polymer matrix,leading to enhanced mechanical performance and steady release of magnesium ion(Mg^(2+))for superior cytocompatibility,higher cell viability,advanced osteogenic differentiation,and cell mineralization capabilities in comparison with the pure PCL.The in-vivo femoral implantation and critical-sized cranial bone defect studies demonstrated the importance of the 3D magnesium microenvironment,as a scaffold that released appropriate Mg^(2+) exhibited remarkably increased bone volume,enhanced angiogenesis,and almost recovered CSD after 8-week implantation.Overall,this study suggests that the magnesium-enriched 3D scaffold is a potential candidate for the treatment of CSD in a cell-free therapeutic approach.
基金financially supported by the Beijing Municipal Science & Technology Commission (No. Z171100002217048)the National Natural Science Foundation of China (No. 51705489)
文摘Diffusion bonding of refractory Nb–Si-based alloy was performed with Ni/Al and Ti/Al nanolayers under the condition of 1473 K/30 MPa/60 min.The NbSS/Nb5Si3 in situ composite with the nominal composition of Nb–22 Ti–16 Si–3 Cr–3 Al–2 Hf was used as the parent material.The joint microstructures were examined by using a scanning electron microscope equipped with an X-ray energy dispersive spectrometer.Shear test was conducted for the bonded joints at room temperature.Within the joint bonded with Ni/Al multilayer,element diffusion occurred between the base metal and the nanolayer,with the reaction products of AlNb2+Ni3 Al,NiAl and AlNi2 Ti phases.The average shear strength was 182 MPa.While using Ti/Al multilayer,the interface mainly consisted of TiAl,(Ti,Nb)Al and(Ti,Nb)2 Al phases,and the corresponding joints exhibited an increased strength of 228 MPa.In this case,the fracture mainly took place in the TiAl phase and presented a typical brittle characteristic.
基金supported by NSFC (Grant Nos. 11522328, 11473070, 11427803 and U1731241)CAS Strategic Pioneer Program on Space Science (Grant Nos. XDA15010600, XDA15052200, XDA15320103 and XDA15320301)the National Key Research and Development Program of China (2018YFA0404202)
文摘The Advanced Space-based Solar Observatory(ASO-S) mission aims to explore the two most spectacular eruptions on the Sun: solar flares and coronal mass ejections(CMEs), and their magnetism.For the study of CMEs, the payload Lyman-alpha Solar Telescope(LST) has been proposed. It includes a traditional white-light coronagraph and a Lyman-alpha coronagraph which opens a new window to CME observations. Polarization measurements taken by white-light coronagraphs are crucial for deriving fundamental physical parameters of CMEs. To make such measurements, there are two options for a Stokes polarimeter which have been applied by existing white-light coronagraphs for space missions. One uses a single or triple linear polarizer, the other involves both a half-wave plate and a linear polarizer. We find that the former option is subject to less uncertainty in the derived Stokes vector propagating from detector noise.The latter option involves two plates which are prone to internal reflections and may have a reduced transmission factor. Therefore, the former option is adopted as our Stokes polarimeter scheme for LST. Based on the parameters of the intended linear polarizer(s) colorPol provided by CODIXX and the half-wave plate 2-APW-L2-012 C by Altechna, it is further shown that the imperfect maximum transmittance of the polarizer significantly increases the variance amplification of Stokes vector by at least about 50% when compared with the ideal case. The relative errors of Stokes vector caused by the imperfection of colorPol polarizer and the uncertainty due to the polarizer assembly in the telescope are estimated to be about 5%. Among the considered parameters, we find that the dominant error comes from the uncertainty in the maximum transmittance of the polarizer.
基金funded by National Key Research, Development Program of China (No. 2017YFE0301305KYWX-002)Sichuan Science and Technology Program (No. 2021YFSY0015)
文摘Atmospheric pressure plasma jet(APPJ)was used to clean nitrogen-containing carbon films(C–N)fabricated by plasma-assisted chemical vapor deposition method employing the plasma surface interaction linear device at Sichuan University(SCU-PSI).The properties of the contaminated films on the surface of pristine and He-plasma pre-irradiated tungsten matrix,such as morphology,crystalline structure,element composition and chemical structure were characterized by scanning electron microscopy,grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy.The experimental results revealed that the removal of C–N film with a thickness of tens of microns can be realized through APPJ cleaning regardless of the morphology of the substrates.Similar removal rates of 16.82 and 13.78μm min^(-1)were obtained for C–N films deposited on a smooth pristine W surface and rough fuzz-covered W surface,respectively.This is a remarkable improvement in comparison to the traditional cleaning method.However,slight surface oxidation was found after APPJ cleaning,but the degree of oxidation was acceptable with an oxidation depth increase of only 3.15 nm.Optical emission spectroscopy analysis and mass spectrometry analysis showed that C–N contamination was mainly removed through chemical reaction with reactive oxygen species during APPJ treatment using air as the working gas.These results make APPJ cleaning a potentially effective method for the rapid removal of C–N films from the wall surfaces of fusion devices.
