Prominent cadmium(Cd)pollution and widespread phoxim(p H)use hinder the growth and medicinal value of Ligusticum chuanxiong Hort.(Chuanxiong).While bioremediation by rhizobacteria helps plants counter pollutants,the s...Prominent cadmium(Cd)pollution and widespread phoxim(p H)use hinder the growth and medicinal value of Ligusticum chuanxiong Hort.(Chuanxiong).While bioremediation by rhizobacteria helps plants counter pollutants,the specific roles of indigenous resistant consortia collected from polluted soils in immobilizing heavy metals,degrading pesticides,and enhancing plant stress tolerance remain insufficiently explored.Here,an indigenous pollutant-resistant consortium(RM)was developed from a highly Cd-polluted area(14.85 mg/kg Cd)as a bioremediation strategy to alleviate stress on Chuanxiong.The RM was specifically enriched with a Cd-p H co-resistant strain,Halomonas spp.TS2.Through16S r RNA sequencing,active microorganisms within RM was identified,including Bacillus,Acinetobacter,Enterococcus,Paraclostridium,and Staphylococcus.Pot experiments demonstrated that RM increased Chuanxiong biomass by 93.38%under Cd-contaminated and by 32.89%under Cd-p H co-contaminated.Furthermore,RM enhanced p H degradation,stabilized soil compounds,and reduced Cd bioavailability,thereby mitigating oxidative damage and altering the diversity and composition of Cd-p H-resistant organisms.These results indicate that utilizing indigenous microbial consortia as a bioremediation strategy can effectively improve soil health and enhance the sustainable cultivation of medicinal herbs in environments heavily contaminated.展开更多
To address the issues of low accuracy and high computational complexity in traditional channelization techniques for ultra-wideband signals,this paper proposes a novel rationally oversampled channelization method to e...To address the issues of low accuracy and high computational complexity in traditional channelization techniques for ultra-wideband signals,this paper proposes a novel rationally oversampled channelization method to enhance the accuracy and efficiency of signal processing.The proposed method is evaluated by implementing and comparing critically sampled and integer oversampled channelization algorithms.A detailed analysis of the impact of different oversampling factors and filter orders on performance is provided.The validity of the proposed algorithm is verified using baseband data from pulsar J0437−4715 observed by the Parkes telescope,demonstrating its effectiveness and correctness.展开更多
The development of highly active and stable bifunctional electrocatalysts in acidic media is crucial to hydrogen production by proton exchange membrane.In this study,we designed a RuO_(2)-IrO_(2)heterostructure cataly...The development of highly active and stable bifunctional electrocatalysts in acidic media is crucial to hydrogen production by proton exchange membrane.In this study,we designed a RuO_(2)-IrO_(2)heterostructure catalyst coupled by carbon quantum dots(CQDs).The catalyst showed excellent electrocatalytic performance for water splitting under acidic conditions.The overpotentials of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)were as low as 180 and 15 mV at 10 mA/cm^(2)in 0.5 M H_(2)SO_(4),respectively.The acid electrolytic cell developed with RuO_(2)-IrO_(2)@CQDs as anode and cathode operated stably at 10 m A/cm^(2)for 120 h.In situ measurements and theoretical calculation reveal that the unique lattice oxygen mechanism path of RuO_(2)-IrO_(2)@CQDs can bypass the OOH^(*)intermediate and breaks the linear relationship of adsorbent evolution mechanism path,resulting in higher OER catalytic activity.展开更多
A two-dimensional model of the silicon NPN monolithic composite transistor is established for the first time by utilizing the semiconductor device simulator, Sentaurus-TCAD. By analyzing the internal distributions of ...A two-dimensional model of the silicon NPN monolithic composite transistor is established for the first time by utilizing the semiconductor device simulator, Sentaurus-TCAD. By analyzing the internal distributions of electric field, current density, and temperature of the device, a detailed investigation on the damage process and mechanism induced by high-power microwaves （HPM） is performed. The results indicate that the temperature elevation occurs in the negative half-period and the temperature drop process is in the positive half-period under the HPM injection from the output port. The damage point is located near the edge of the base-emitter junction of T2, while with the input injection it exists between the base and the emitter of T2. Comparing these two kinds of injection, the input injection is more likely to damage the device than the output injection. The dependences of the damage energy threshold and the damage power threshold causing the device failure on the pulse-width are obtained, and the formulas obtained have the same form as the experimental equations, which demonstrates that more power is required to destroy the device if the pulse-width is shorter. Furthermore, the simulation result in this paper has a good coincidence with the experimental result.展开更多
Water electrolysis using proton-exchange membranes is one of the most promising technologies for carbon-neutral and sustainable energy production.Generally,the overall efficiency of water splitting is limited by the o...Water electrolysis using proton-exchange membranes is one of the most promising technologies for carbon-neutral and sustainable energy production.Generally,the overall efficiency of water splitting is limited by the oxygen evolution reaction(OER).Nevertheless,a trade-off between activity and stability exists for most electrocatalytic materials in strong acids and oxidizing media,and the development of efficient and stable catalytic materials has been an important focus of research.In this view,gaining in-depth insights into the OER system,particularly the interactions between reaction intermediates and active sites,is significantly important.To this end,this review introduces the fundamentals of the OER over Ru-based materials,including the conventional adsorbate evolution mechanism,lattice oxygen oxidation mechanism,and oxide path mechanism.Moreover,the up-to-date progress of representative modifications for improving OER performance is further discussed with reference to specific mechanisms,such as tuning of geometric,electronic structures,incorporation of proton acceptors,and optimization of metal-oxygen covalency.Finally,some valuable insights into the challenges and opportunities for OER electrocatalysts are provided with the aim to promote the development of next-generation catalysts with high activity and excellent stability.展开更多
Dinitrogen fixation is one of the key reactions in chemistry, which is closely associated with food, environment, and energy. It has been recently recognized that the hydride materials containing negatively charged hy...Dinitrogen fixation is one of the key reactions in chemistry, which is closely associated with food, environment, and energy. It has been recently recognized that the hydride materials containing negatively charged hydrogen(H~-) show promises for Nfixation and hydrogenation to ammonia. Herein, we report that rare earth metal hydrides such as lanthanum hydride can also fix Neither by heating to 200 °C or ball milling under ambient Npressure and temperature. The Nfixation by lanthanum hydride may proceed via an intermediate lanthanum hydride-nitride(La-H-N) structure to form the final lanthanum nitride product. The hydride ion functions as an electron donor, which provides electrons for Nactivation possibly mediated by the lanthanum atoms. It is observed that N–H bond is not formed during the Nfixation process, which is distinctly different from the alkali or alkaline earth metal hydrides. The hydrolysis of La-H-N to ammonia is feasible using water as the hydrogen source. These results provide new insights into the nitrogen fixation by hydride materials and more efforts are needed for the development of rare earth metal-based catalysts and/or nitrogen carriers for ammonia synthesis processes.展开更多
With establishment of thermal and numerical simulation models,the influence of reduction amount on solidification structure,segregation and shrinkage porosity of continuous casting(CC)billets was investigated.The ther...With establishment of thermal and numerical simulation models,the influence of reduction amount on solidification structure,segregation and shrinkage porosity of continuous casting(CC)billets was investigated.The thermal–mechanical coupled simulation results indicated that with an increase in reduction amount,the temperature in the central area decreases,and the reduction efficiency firstly increases and then decreases,reaching the maximum value at reduction amount of 6 mm.Metallographic analysis showed that increasing the reduction amount is beneficial for the refinement of central solidification structure.Moreover,the internal cracks are more likely to appear at higher reduction efficiency.The X-ray computerized tomography results revealed that a higher reduction amount can significantly reduce the volume fraction and equivalent diameter of the central shrinkage porosities of CC billets and increase the sphericity of them.Simultaneously,the macrosegregation of carbon along the central line is improved as the reduction amount increases;while the reduction amount exceeds 8 mm,the segregation degree will not change any more.展开更多
As artificial intelligence(AI)technology has continued to develop,its efficient data processing and pattern recognition capabilities have significantly improved the precision and speed of decision-making processes,and...As artificial intelligence(AI)technology has continued to develop,its efficient data processing and pattern recognition capabilities have significantly improved the precision and speed of decision-making processes,and it has been widely applied across various fields.In the field of astronomy,AI techniques have demonstrated unique advantages,particularly in the identification of pulsars and their candidates.AI is able to address the challenges of pulsar celestial body identification and classification because of its accuracy and efficiency.This paper systematically surveys commonly used AI models for pulsar candidate identification,analyzing and discussing the typical applications of machine learning,artificial neural networks,convolutional neural networks,and generative adversarial networks in candidate identification.Furthermore,it explores how th.e introduction of AI techniques not only enhances the efficiency and accuracy of pulsar identification but also provides new perspectives and tools for pulsar survey data processing,thus playing a significant role in advancing pulsar research and the field of astronomy.展开更多
Natural gas hydrate(NGH)has a bright future as a clean energy source with huge reserves.Coring is one of the most direct methods for NGH exploration and research.Preserving the in-situ properties of the core as much a...Natural gas hydrate(NGH)has a bright future as a clean energy source with huge reserves.Coring is one of the most direct methods for NGH exploration and research.Preserving the in-situ properties of the core as much as possible during the coring process is crucial for the assessment of NGH resources.However,most existing NGH coring techniques cannot preserve the in-situ temperature of NGH,leading to distortion of the physical properties of the obtained core,which makes it difficult to effectively guide NGH exploration and development.To overcome this limitation,this study introduces an innovative active temperature-preserved coring method for NGH utilizing phase change materials(PCM).An active temperature-preserved corer(ATPC)is designed and developed,and an indoor experimental system is established to investigate the heat transfer during the coring process.Based on the experimental results under different environment temperatures,a heat transfer model for the entire ATPC coring process has been established.The indoor experimental results are consistent with the theoretical predictions of the heat transfer model,confirming its validity.This model has reconstructed the temperature changes of the NGH core during the coring process,demonstrating that compared to the traditional coring method with only passive temperature-preserved measures,ATPC can effectively reduce the core temperature by more than 5.25℃.With ATPC,at environment temperatures of 15,20,25,and 30℃,the duration of low-temperature state for the NGH core is 53.85,32.87,20.32,and 11.83 min,respectively.These findings provide new perspectives on temperature-preserving core sampling in NGH and provide technical support for exploration and development in NGH.展开更多
Tongue squamous cell carcinoma(TSCC)is a prevalent malignancy that afflicts the head and neck area and presents a high incidence of metastasis and invasion.Accurate diagnosis and effective treatment are essential for ...Tongue squamous cell carcinoma(TSCC)is a prevalent malignancy that afflicts the head and neck area and presents a high incidence of metastasis and invasion.Accurate diagnosis and effective treatment are essential for enhancing the quality of life and the survival rates of TSCC patients.The current treatment modalities for TSCC frequently suffer from a lack of specificity and efficacy.Nanoparticles with diagnostic and photothermal therapeutic properties may offer a new approach for the targeted therapy of TSCC.However,inadequate accumulation of photosensitizers at the tumor site diminishes the efficacy of photothermal therapy(PTT).This study modified gold nanodots(AuNDs)with the TSCC-targeting peptide HN-1 to improve the selectivity and therapeutic effects of PTT.The Au-HN-1 nanosystem effectively targeted the TSCC cells and was rapidly delivered to the tumor tissues compared to the AuN Ds.The enhanced accumulation of photosensitizing agents at tumor sites achieved significant PTT effects in a mouse model of TSCC.Moreover,owing to its stable long-term fluorescence and high X-ray attenuation coefficient,the Au-HN-1 nanosystem can be used for fluorescence and computed tomography imaging of TSCC,rendering it useful for early tumor detection and accurate delineation of surgical margins.In conclusion,Au-HN-1 represents a promising nanomedicine for imaging-based diagnosis and targeted PTT of TSCC.展开更多
With the world has become the global village,communication between countries is becoming increasingly common.As an important tool for international communication,English has become increasingly important.However,for s...With the world has become the global village,communication between countries is becoming increasingly common.As an important tool for international communication,English has become increasingly important.However,for students in private vocational colleges,English listening anxiety is a common phenomenon,which not only affects the learning ability of students but also restricts the improvement of their comprehensive English ability.In this study,242 first-year students of a private vocational college in Hainan,were used as the study objects,and the level,causes and influencing factors of their English listening anxiety were deeply analyzed via a questionnaire survey.Strategies to alleviate students’English listening anxiety were discussed from the three aspects of teachers,students and schools.The conclusions of this study have certain theoretical and practical significance for improving the the teaching state for English listening to college students from private higher colleges.Meanwhile,It can also enhancing the learning effect of students to English.The comprehensive use of various strategies can effectively relieve students’English listening anxiety,improve their English listening level and learning enthusiasm,and make great contributions to the future career development for them.However,owing to limitations in terms of research time and conditions,this study has several limitations.Future studies can further expand the research scope,increase the diversity and quantity of research samples,and adopt a combination of multiple research methods to conduct a more in-depth discussion on this issue.展开更多
Food-derived bioactive peptides(FBPs),particularly those with ten or fewer amino acid residues and a molecular weight below 1300 Da,have gained increasing attention for their safe,diverse structures and specific biolo...Food-derived bioactive peptides(FBPs),particularly those with ten or fewer amino acid residues and a molecular weight below 1300 Da,have gained increasing attention for their safe,diverse structures and specific biological activities.The development of FBP-based functional foods and potential medications depends on understanding their structure–activity relationships(SARs),stability,and bioavailability properties.In this review,we provide an in-depth overview of the roles of FBPs in treating various diseases,including Alzheimer’s disease,hypertension,type 2 diabetes mellitus,liver diseases,and inflammatory bowel diseases,based on the literature from July 2017 to Mar.2023.Subsequently,attention is directed toward elucidating the associations between the bioactivities and structural characteristics(e.g.,molecular weight and the presence of specific amino acids within sequences and compositions)of FBPs.We also discuss in silico approaches for FBP screening and their limitations.Finally,we summarize recent advancements in formulation techniques to improve the bioavailability of FBPs in the food industry,thereby contributing to healthcare applications.展开更多
Glioma is the most common malignant tumor of the brain. The postoperative recurrence rate was high,and the 2-year survival rate only increased by 20%–25%. The reason is the blood-brain barrier(BBB). BBB is a physical...Glioma is the most common malignant tumor of the brain. The postoperative recurrence rate was high,and the 2-year survival rate only increased by 20%–25%. The reason is the blood-brain barrier(BBB). BBB is a physical barrier that stabilizes the physiological environment of brain tissue and protects the central nervous system from the invasion of harmful substances. Drug delivery based on nanotechnology and nanocarriers has attracted much attention due to its biological safety, continuous drug release time,increasing solubility, biological drug activity, and enhanced BBB permeability. By modifying different substances on the surface of nanocarriers, the BBB is bypassed by receptor-mediated and cell endocytosis and exocytosis. In addition, the purpose of bypassing BBB-targeted drug delivery can also be achieved by intranasal administration and local administration. This paper reviews different target transport mechanisms, mainly in invasive and non-invasive strategies, the nanocarriers that have made progress and the nanocarrier strategy of bypassing BBB are listed.展开更多
Marine gas hydrates are highly sensitive to temperature and pressure fluctuations,and deviations from in-situ conditions may cause irreversible changes in phase state,microstructure,and mechanical properties.However,c...Marine gas hydrates are highly sensitive to temperature and pressure fluctuations,and deviations from in-situ conditions may cause irreversible changes in phase state,microstructure,and mechanical properties.However,conventional samplers often fail to maintain sealing and thermal stability,resulting in low sampling success rates.To address these challenges,an in-situ temperature-and pressure-preserved sampler for marine applications has been developed.The experimental results indicate that the selfdeveloped magnetically controlled pressure-preserved controller reliably achieves autonomous triggering and self-sealing,provides an initial sealing force of 83 N,and is capable of maintaining pressures up to 40 MPa.Additionally,a custom-designed intelligent temperature control chip and high-precision sensors were integrated into the sampler.Through the design of an optimized heat transfer structure,a temperature-preserved system was developed,achieving no more than a 0.3℃ rise in temperature within 2 h.The performance evaluation and sampling operations of the sampler were conducted at the Haima Cold Seep in the South China Sea,resulting in the successful recovery of hydrate maintained under in-situ pressure of 13.8 MPa and a temperature of 6.5℃.This advancement enables the acquisition of high-fidelity hydrate samples,providing critical support for the safe exploitation and scientific analysis of marine gas hydrate resources.展开更多
As-rolled titanium/steel composite plate has poor plastic deformation ability,and it is difficult to achieve synergistic deformation,especially for dissimilar metals with very different plastic deformation abilities.T...As-rolled titanium/steel composite plate has poor plastic deformation ability,and it is difficult to achieve synergistic deformation,especially for dissimilar metals with very different plastic deformation abilities.The 304/TC4 composite plate with corrugated interface was manufactured using the asymmetric rolling with local strong stress method.The changing rules of bonding strength and synergistic deformation ability of corrugated interface under different annealing process parameters were studied.The results show that in the range of 550–850℃,especially after the temperature exceeds 650℃,with increasing the annealing temperature and time,the difference of microstructure between peak and trough positions increases,and the bonding strength of the composite plate decreases gradually.Especially,the interfacial bonding strength of the plate sharply decreases at 750℃ due to the rapid growth of intermetallic compounds at the interface and the diffusion holes caused by the difference of element diffusion.The 304/TC4 composite plate has the best synergistic deformation ability when annealing at 650℃/2 h,with the elongation reaching 35%and the tensile strength decreasing to 852 MPa.High interfacial bonding strength and moderate matrix recovery are important prerequisites for synergistic deformation of composite plates.展开更多
Voids play an important role in the fatigue behaviour of polycrystal materials.In this paper,the effects of three factors affecting the stress concentration factors(SCFs)near voids,i.e.,size,depth,and applied load,are...Voids play an important role in the fatigue behaviour of polycrystal materials.In this paper,the effects of three factors affecting the stress concentration factors(SCFs)near voids,i.e.,size,depth,and applied load,are investigated by employing crystal plasticity constitutive models in polycrystal bulks.The results indicate that SCF is dominated by the void size,while void depth and stress level play secondary roles.The SCF fluctuates by the orientation differences among grains and increases with increasing the size of the void.Finally,based on sensitivity examination of orientations and configurations of grains sur-rounding the void,an empirical multivariable-coupled formula is proposed to assess SCF near voids considering anisotropy,and the presented model is in good agreement with the simulation results.展开更多
The microscopic occurrence characteristics primarily constrain the enrichment and mobility of shale oil.This study collected the lacustrine shales from the Palaeogene Funing Formation in the Gaoyou Sag, Subei Basin. C...The microscopic occurrence characteristics primarily constrain the enrichment and mobility of shale oil.This study collected the lacustrine shales from the Palaeogene Funing Formation in the Gaoyou Sag, Subei Basin. Conventional and multistage Rock-Eval, scanning electron microscopy, and nuclear magnetic resonance(NMR) T1-T2were performed to analyze the contents and occurrence characteristics of shale oil. Low-temperature nitrogen adsorption-desorption(LTNA/D) experiments were conducted on the shales before and after extraction. The relationships between shale oil occurrence with organic matter and pore structures were then discussed. Predominantly, the shale oil in the Funing Formation is found within fractures, with secondary occurrences in interparticle pores linked to brittle minerals and sizeable intraparticle pores associated with clay minerals. The selected shales can be categorized into two types based on the nitrogen isotherms. Type A shales are characterized by high contents of felsic and calcareous minerals but low clay minerals, with larger TOC and shale oil values. Conversely, Type B shales are marked by abundant clay minerals but diminished TOC and shale oil contents. The lower BET specific surface area(SSA), larger average pore diameter, and simpler pore surfaces and pore structures lead to the Type A shales being more conducive to shale oil enrichment and mobility. Shale oil content is predominantly governed by the abundance of organic matter, while an overabundance of organic matter typically equates to a reduced ratio of free oil and diminished fluidity. The BET SSA, volumes of pores less than 25 and 100 nm at extracted state all correlate negatively with total and adsorbed oil contents but display no correlation with free oil, while they have positive relationships with capillary-bound water.Consequently, pore water is mainly saturated in micropores(<25 nm) and minipores(25-100 nm), as well as adsorbed oil, while free oil, i.e., bound and movable oil, primarily exists in mesopores(100-1000 nm) and macropores(>1000 nm). These findings may enhance the understanding of the microscopic occurrence characteristics of shale oil and will contribute to guide resource estimation and shale oil sweet spot exploitation in the Gaoyou Sag, Subei Basin.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51978576,42207021 and 52370177)Sichuan Province Science and Technology Support Program(Nos.2023ZHCG0058,2025ZNSFSC0194 and 2024NSFSC0131)+1 种基金the Fundamental Research Funds for the Central Universities(No.2682024ZTPY012)the Science and Technology Project of Sichuan Tobacco Company of China National Tobacco Corporation(Nos.SCYC202109 and SCYC202409)。
文摘Prominent cadmium(Cd)pollution and widespread phoxim(p H)use hinder the growth and medicinal value of Ligusticum chuanxiong Hort.(Chuanxiong).While bioremediation by rhizobacteria helps plants counter pollutants,the specific roles of indigenous resistant consortia collected from polluted soils in immobilizing heavy metals,degrading pesticides,and enhancing plant stress tolerance remain insufficiently explored.Here,an indigenous pollutant-resistant consortium(RM)was developed from a highly Cd-polluted area(14.85 mg/kg Cd)as a bioremediation strategy to alleviate stress on Chuanxiong.The RM was specifically enriched with a Cd-p H co-resistant strain,Halomonas spp.TS2.Through16S r RNA sequencing,active microorganisms within RM was identified,including Bacillus,Acinetobacter,Enterococcus,Paraclostridium,and Staphylococcus.Pot experiments demonstrated that RM increased Chuanxiong biomass by 93.38%under Cd-contaminated and by 32.89%under Cd-p H co-contaminated.Furthermore,RM enhanced p H degradation,stabilized soil compounds,and reduced Cd bioavailability,thereby mitigating oxidative damage and altering the diversity and composition of Cd-p H-resistant organisms.These results indicate that utilizing indigenous microbial consortia as a bioremediation strategy can effectively improve soil health and enhance the sustainable cultivation of medicinal herbs in environments heavily contaminated.
基金supported by the National Key R&D Program of China Nos.2021YFC2203502 and 2022YFF0711502the National Natural Science Foundation of China(NSFC)(12173077)+5 种基金the Chinese Academy of Sciences(CAS)“Light of West China”Program(No.xbzg-zdsys-202410)the Tianshan Talent Project of Xinjiang Uygur Autonomous Region(2022TSYCCX0095 and 2023TSYCCX0112)the Scientific Instrument Developing Project of the Chinese Academy of Sciences,grant No.PTYQ2022YZZD01China National Astronomical Data Center(NADC)the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China(MOF)and administrated by the Chinese Academy of Sciences(CAS)Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01A360).
文摘To address the issues of low accuracy and high computational complexity in traditional channelization techniques for ultra-wideband signals,this paper proposes a novel rationally oversampled channelization method to enhance the accuracy and efficiency of signal processing.The proposed method is evaluated by implementing and comparing critically sampled and integer oversampled channelization algorithms.A detailed analysis of the impact of different oversampling factors and filter orders on performance is provided.The validity of the proposed algorithm is verified using baseband data from pulsar J0437−4715 observed by the Parkes telescope,demonstrating its effectiveness and correctness.
基金supported by the Natural Science Foundation of Shandong Province ZR2024MB087the National Natural Science Foundation of China(No.52122308,51973200,52202050,and 21905253)+3 种基金the Natural Science Foundation of Henan(202300410372)the Joint Fund of Science and Technology R&D Plan of Henan Province(232301420042)the China Postdoctoral Science Foundation(2022TQ0286)the Center for Modern Analysis and Gene Sequencing of Zhengzhou University for supporting this project。
文摘The development of highly active and stable bifunctional electrocatalysts in acidic media is crucial to hydrogen production by proton exchange membrane.In this study,we designed a RuO_(2)-IrO_(2)heterostructure catalyst coupled by carbon quantum dots(CQDs).The catalyst showed excellent electrocatalytic performance for water splitting under acidic conditions.The overpotentials of oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)were as low as 180 and 15 mV at 10 mA/cm^(2)in 0.5 M H_(2)SO_(4),respectively.The acid electrolytic cell developed with RuO_(2)-IrO_(2)@CQDs as anode and cathode operated stably at 10 m A/cm^(2)for 120 h.In situ measurements and theoretical calculation reveal that the unique lattice oxygen mechanism path of RuO_(2)-IrO_(2)@CQDs can bypass the OOH^(*)intermediate and breaks the linear relationship of adsorbent evolution mechanism path,resulting in higher OER catalytic activity.
基金supported by the National Natural Science Foundation of China(U24A2079,22272003,22301013)the Program of Beijing Municipal Education Commission(KZ20231000506)+1 种基金the National Key Research and Development Program of China(2023YFB3810800)the China Postdoctoral Science Foundation(2025M770117,GZC20250088)。
文摘Carbon dots(CDs),as emerging zero-dimensional carbon-based nanomaterials,demonstrate immense potential across optical displays,bioimaging,chemical sensing,information anti-counterfeiting,and optoelectronic devices.This promise stems from their exceptional tunable photoluminescence,low toxicity,biocompatibility,and abundant raw material sources.Since their discovery,research has centered on resolving controversies regarding classification,formation mechanism,microstructure,and luminescence principles while achieving controllable optoelectronic properties.Applications have evolved from basic fluorescent labeling to advanced domains including multimodal theranostics,high-sensitivity(bio/chemical)sensing,stable optoelectronic devices,intelligent anticounterfeiting systems,and environmental/energy catalysis.Future challenges demand breakthroughs in structural homogeneity/scalable eco-fabrication,universal structure-opto/electronic-property models,stability/efficiency in complex environments,and multifunctional synergy(e.g.,photo-electro-catalysis).This comprehensive review systematically examines milestone advances in CDs research over the past decade—spanning synthesis methodologies,photo/electronic property modulation mechanisms,and innovative applications—while dissecting key challenges and envisioning future pathways as versatile intelligent nanoplatforms.
文摘A two-dimensional model of the silicon NPN monolithic composite transistor is established for the first time by utilizing the semiconductor device simulator, Sentaurus-TCAD. By analyzing the internal distributions of electric field, current density, and temperature of the device, a detailed investigation on the damage process and mechanism induced by high-power microwaves （HPM） is performed. The results indicate that the temperature elevation occurs in the negative half-period and the temperature drop process is in the positive half-period under the HPM injection from the output port. The damage point is located near the edge of the base-emitter junction of T2, while with the input injection it exists between the base and the emitter of T2. Comparing these two kinds of injection, the input injection is more likely to damage the device than the output injection. The dependences of the damage energy threshold and the damage power threshold causing the device failure on the pulse-width are obtained, and the formulas obtained have the same form as the experimental equations, which demonstrates that more power is required to destroy the device if the pulse-width is shorter. Furthermore, the simulation result in this paper has a good coincidence with the experimental result.
基金partly supported by the National Natural Science Foundation of China(NSFCs,52202050,52122308,21905253,51973200)the China Postdoctoral Science Foundation(2022TQ0286)the Natural Science Foundation of Henan(202300410372)。
文摘Water electrolysis using proton-exchange membranes is one of the most promising technologies for carbon-neutral and sustainable energy production.Generally,the overall efficiency of water splitting is limited by the oxygen evolution reaction(OER).Nevertheless,a trade-off between activity and stability exists for most electrocatalytic materials in strong acids and oxidizing media,and the development of efficient and stable catalytic materials has been an important focus of research.In this view,gaining in-depth insights into the OER system,particularly the interactions between reaction intermediates and active sites,is significantly important.To this end,this review introduces the fundamentals of the OER over Ru-based materials,including the conventional adsorbate evolution mechanism,lattice oxygen oxidation mechanism,and oxide path mechanism.Moreover,the up-to-date progress of representative modifications for improving OER performance is further discussed with reference to specific mechanisms,such as tuning of geometric,electronic structures,incorporation of proton acceptors,and optimization of metal-oxygen covalency.Finally,some valuable insights into the challenges and opportunities for OER electrocatalysts are provided with the aim to promote the development of next-generation catalysts with high activity and excellent stability.
基金the financial support from the National Key R&D Program of China(2021YFB4000401)the National Natural Science Foundation of China(Grant Nos.21922205,21872137,22109158,and 51801197)+2 种基金the Youth Innovation Promotion Association CAS(Grant Nos.2018213,2019189,2022180)the Liaoning Revitalization Talents Program(Grant Nos.XLYC2007173,XLYC2002076)the K.C.Wong Education Foundation(Grant No.GJTD-2018-06)。
文摘Dinitrogen fixation is one of the key reactions in chemistry, which is closely associated with food, environment, and energy. It has been recently recognized that the hydride materials containing negatively charged hydrogen(H~-) show promises for Nfixation and hydrogenation to ammonia. Herein, we report that rare earth metal hydrides such as lanthanum hydride can also fix Neither by heating to 200 °C or ball milling under ambient Npressure and temperature. The Nfixation by lanthanum hydride may proceed via an intermediate lanthanum hydride-nitride(La-H-N) structure to form the final lanthanum nitride product. The hydride ion functions as an electron donor, which provides electrons for Nactivation possibly mediated by the lanthanum atoms. It is observed that N–H bond is not formed during the Nfixation process, which is distinctly different from the alkali or alkaline earth metal hydrides. The hydrolysis of La-H-N to ammonia is feasible using water as the hydrogen source. These results provide new insights into the nitrogen fixation by hydride materials and more efforts are needed for the development of rare earth metal-based catalysts and/or nitrogen carriers for ammonia synthesis processes.
基金financially supported by the National Natural Science Foundation of China(Nos.52127807 and 52271035)National Science and Technology Major Project of China(No.J2019-Ⅵ-0023)the fund of the State Key Laboratory of Solidification Processing(Northwestern Polytechnical University)(No.SKLSP202107).
文摘With establishment of thermal and numerical simulation models,the influence of reduction amount on solidification structure,segregation and shrinkage porosity of continuous casting(CC)billets was investigated.The thermal–mechanical coupled simulation results indicated that with an increase in reduction amount,the temperature in the central area decreases,and the reduction efficiency firstly increases and then decreases,reaching the maximum value at reduction amount of 6 mm.Metallographic analysis showed that increasing the reduction amount is beneficial for the refinement of central solidification structure.Moreover,the internal cracks are more likely to appear at higher reduction efficiency.The X-ray computerized tomography results revealed that a higher reduction amount can significantly reduce the volume fraction and equivalent diameter of the central shrinkage porosities of CC billets and increase the sphericity of them.Simultaneously,the macrosegregation of carbon along the central line is improved as the reduction amount increases;while the reduction amount exceeds 8 mm,the segregation degree will not change any more.
基金supported by the National Key R&D Program of China(2021YFC2203502 and 2022YFF0711502)the National Natural Science Foundation of China(NSFC)(12173077)+4 种基金the Tianshan Talent Project of Xinjiang Uygur Autonomous Region(2022TSYCCX0095 and 2023TSYCCX0112)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(PTYQ2022YZZD01)China National Astronomical Data Center(NADC)the Operation,Maintenance and Upgrading Fund for Astronomical Telescopes and Facility Instruments,budgeted from the Ministry of Finance of China(MOF)and administrated by the Chinese Academy of Sciences(CAS)Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01A360)。
文摘As artificial intelligence(AI)technology has continued to develop,its efficient data processing and pattern recognition capabilities have significantly improved the precision and speed of decision-making processes,and it has been widely applied across various fields.In the field of astronomy,AI techniques have demonstrated unique advantages,particularly in the identification of pulsars and their candidates.AI is able to address the challenges of pulsar celestial body identification and classification because of its accuracy and efficiency.This paper systematically surveys commonly used AI models for pulsar candidate identification,analyzing and discussing the typical applications of machine learning,artificial neural networks,convolutional neural networks,and generative adversarial networks in candidate identification.Furthermore,it explores how th.e introduction of AI techniques not only enhances the efficiency and accuracy of pulsar identification but also provides new perspectives and tools for pulsar survey data processing,thus playing a significant role in advancing pulsar research and the field of astronomy.
基金financially supported by Shenzhen Science and Technology Program(Nos.JSGG20220831105002005 and KJZD20231025152759002)the National Natural Science Foundation of China(Nos.52274133 and 523B2101).
文摘Natural gas hydrate(NGH)has a bright future as a clean energy source with huge reserves.Coring is one of the most direct methods for NGH exploration and research.Preserving the in-situ properties of the core as much as possible during the coring process is crucial for the assessment of NGH resources.However,most existing NGH coring techniques cannot preserve the in-situ temperature of NGH,leading to distortion of the physical properties of the obtained core,which makes it difficult to effectively guide NGH exploration and development.To overcome this limitation,this study introduces an innovative active temperature-preserved coring method for NGH utilizing phase change materials(PCM).An active temperature-preserved corer(ATPC)is designed and developed,and an indoor experimental system is established to investigate the heat transfer during the coring process.Based on the experimental results under different environment temperatures,a heat transfer model for the entire ATPC coring process has been established.The indoor experimental results are consistent with the theoretical predictions of the heat transfer model,confirming its validity.This model has reconstructed the temperature changes of the NGH core during the coring process,demonstrating that compared to the traditional coring method with only passive temperature-preserved measures,ATPC can effectively reduce the core temperature by more than 5.25℃.With ATPC,at environment temperatures of 15,20,25,and 30℃,the duration of low-temperature state for the NGH core is 53.85,32.87,20.32,and 11.83 min,respectively.These findings provide new perspectives on temperature-preserving core sampling in NGH and provide technical support for exploration and development in NGH.
基金supported by the Science and Technology Projects of Jilin Provincial Department of Science and Technology(Grant/Award Numbers:20240305037YY)National Key Research and Development Program of China(2021YFC2400603)+1 种基金the Joint Funds of the National Natural Science Foundation of China(Grant No.U23A20269)the Jilin University young teachers and students cross-disciplinary training project(Grant No.2023-JCXK-08,2024-JCXK-07)。
文摘Tongue squamous cell carcinoma(TSCC)is a prevalent malignancy that afflicts the head and neck area and presents a high incidence of metastasis and invasion.Accurate diagnosis and effective treatment are essential for enhancing the quality of life and the survival rates of TSCC patients.The current treatment modalities for TSCC frequently suffer from a lack of specificity and efficacy.Nanoparticles with diagnostic and photothermal therapeutic properties may offer a new approach for the targeted therapy of TSCC.However,inadequate accumulation of photosensitizers at the tumor site diminishes the efficacy of photothermal therapy(PTT).This study modified gold nanodots(AuNDs)with the TSCC-targeting peptide HN-1 to improve the selectivity and therapeutic effects of PTT.The Au-HN-1 nanosystem effectively targeted the TSCC cells and was rapidly delivered to the tumor tissues compared to the AuN Ds.The enhanced accumulation of photosensitizing agents at tumor sites achieved significant PTT effects in a mouse model of TSCC.Moreover,owing to its stable long-term fluorescence and high X-ray attenuation coefficient,the Au-HN-1 nanosystem can be used for fluorescence and computed tomography imaging of TSCC,rendering it useful for early tumor detection and accurate delineation of surgical margins.In conclusion,Au-HN-1 represents a promising nanomedicine for imaging-based diagnosis and targeted PTT of TSCC.
文摘With the world has become the global village,communication between countries is becoming increasingly common.As an important tool for international communication,English has become increasingly important.However,for students in private vocational colleges,English listening anxiety is a common phenomenon,which not only affects the learning ability of students but also restricts the improvement of their comprehensive English ability.In this study,242 first-year students of a private vocational college in Hainan,were used as the study objects,and the level,causes and influencing factors of their English listening anxiety were deeply analyzed via a questionnaire survey.Strategies to alleviate students’English listening anxiety were discussed from the three aspects of teachers,students and schools.The conclusions of this study have certain theoretical and practical significance for improving the the teaching state for English listening to college students from private higher colleges.Meanwhile,It can also enhancing the learning effect of students to English.The comprehensive use of various strategies can effectively relieve students’English listening anxiety,improve their English listening level and learning enthusiasm,and make great contributions to the future career development for them.However,owing to limitations in terms of research time and conditions,this study has several limitations.Future studies can further expand the research scope,increase the diversity and quantity of research samples,and adopt a combination of multiple research methods to conduct a more in-depth discussion on this issue.
基金supported by the Chinese Nutrition Society(CNS)Nutrition Science Foundation–Sino Nutri-food Oligopeptide Nutrition Research Fund(No.CNS-FF2019A22)the National Natural Science Foundation of China(Nos.52173141 and 82102192).
文摘Food-derived bioactive peptides(FBPs),particularly those with ten or fewer amino acid residues and a molecular weight below 1300 Da,have gained increasing attention for their safe,diverse structures and specific biological activities.The development of FBP-based functional foods and potential medications depends on understanding their structure–activity relationships(SARs),stability,and bioavailability properties.In this review,we provide an in-depth overview of the roles of FBPs in treating various diseases,including Alzheimer’s disease,hypertension,type 2 diabetes mellitus,liver diseases,and inflammatory bowel diseases,based on the literature from July 2017 to Mar.2023.Subsequently,attention is directed toward elucidating the associations between the bioactivities and structural characteristics(e.g.,molecular weight and the presence of specific amino acids within sequences and compositions)of FBPs.We also discuss in silico approaches for FBP screening and their limitations.Finally,we summarize recent advancements in formulation techniques to improve the bioavailability of FBPs in the food industry,thereby contributing to healthcare applications.
基金supported by the National Natural Science Foundation of China (Nos. 22074072, 22274083)the Shandong Provincial Natural Science Foundation (Nos. ZR2022LZY022, ZR2023LZY005)+2 种基金the Science and Technology Planning Project of South District of Qingdao City (No. 2022–4–005-YY)the Exploration project of the State Key Laboratory of Bio Fibers and Eco Textiles of Qingdao University (No. TSKT202101)the High-Level Discipline Project of Shandong Province。
文摘Glioma is the most common malignant tumor of the brain. The postoperative recurrence rate was high,and the 2-year survival rate only increased by 20%–25%. The reason is the blood-brain barrier(BBB). BBB is a physical barrier that stabilizes the physiological environment of brain tissue and protects the central nervous system from the invasion of harmful substances. Drug delivery based on nanotechnology and nanocarriers has attracted much attention due to its biological safety, continuous drug release time,increasing solubility, biological drug activity, and enhanced BBB permeability. By modifying different substances on the surface of nanocarriers, the BBB is bypassed by receptor-mediated and cell endocytosis and exocytosis. In addition, the purpose of bypassing BBB-targeted drug delivery can also be achieved by intranasal administration and local administration. This paper reviews different target transport mechanisms, mainly in invasive and non-invasive strategies, the nanocarriers that have made progress and the nanocarrier strategy of bypassing BBB are listed.
基金financially supported by Shenzhen Science and Technology Program(Nos.JSGG20220831105002005 and KJZD20231025152759002)Support from the National Natural Science Foundation of China(Nos.52374357 and 523B2101)funded by the Shared Voyages Project for Deep-sea and Abyss Scientific Research and Equipment Sea Trials of Hainan Deep-Sea Technology Innovation Center(No.DSTIC-GXHC-2022002)。
文摘Marine gas hydrates are highly sensitive to temperature and pressure fluctuations,and deviations from in-situ conditions may cause irreversible changes in phase state,microstructure,and mechanical properties.However,conventional samplers often fail to maintain sealing and thermal stability,resulting in low sampling success rates.To address these challenges,an in-situ temperature-and pressure-preserved sampler for marine applications has been developed.The experimental results indicate that the selfdeveloped magnetically controlled pressure-preserved controller reliably achieves autonomous triggering and self-sealing,provides an initial sealing force of 83 N,and is capable of maintaining pressures up to 40 MPa.Additionally,a custom-designed intelligent temperature control chip and high-precision sensors were integrated into the sampler.Through the design of an optimized heat transfer structure,a temperature-preserved system was developed,achieving no more than a 0.3℃ rise in temperature within 2 h.The performance evaluation and sampling operations of the sampler were conducted at the Haima Cold Seep in the South China Sea,resulting in the successful recovery of hydrate maintained under in-situ pressure of 13.8 MPa and a temperature of 6.5℃.This advancement enables the acquisition of high-fidelity hydrate samples,providing critical support for the safe exploitation and scientific analysis of marine gas hydrate resources.
基金supported by the Major Program of National Natural Science Foundation of China(U22A20188)the Natural Science Foundation of Shanxi Province(202303021224002)+1 种基金the special fund for Science and Technology Innovation Teams of Shanxi Province(202304051001025)the Open Research Fund from the Hai’an and Taiyuan University of Technology Advanced Manufacturing and Intelligent Equipment Industrial Research Institute(2023HA-TYUTKFYF036).
文摘As-rolled titanium/steel composite plate has poor plastic deformation ability,and it is difficult to achieve synergistic deformation,especially for dissimilar metals with very different plastic deformation abilities.The 304/TC4 composite plate with corrugated interface was manufactured using the asymmetric rolling with local strong stress method.The changing rules of bonding strength and synergistic deformation ability of corrugated interface under different annealing process parameters were studied.The results show that in the range of 550–850℃,especially after the temperature exceeds 650℃,with increasing the annealing temperature and time,the difference of microstructure between peak and trough positions increases,and the bonding strength of the composite plate decreases gradually.Especially,the interfacial bonding strength of the plate sharply decreases at 750℃ due to the rapid growth of intermetallic compounds at the interface and the diffusion holes caused by the difference of element diffusion.The 304/TC4 composite plate has the best synergistic deformation ability when annealing at 650℃/2 h,with the elongation reaching 35%and the tensile strength decreasing to 852 MPa.High interfacial bonding strength and moderate matrix recovery are important prerequisites for synergistic deformation of composite plates.
基金supported by the National Natural Science Foundation of China(Grant Nos.12022210 and 12032001)。
文摘Voids play an important role in the fatigue behaviour of polycrystal materials.In this paper,the effects of three factors affecting the stress concentration factors(SCFs)near voids,i.e.,size,depth,and applied load,are investigated by employing crystal plasticity constitutive models in polycrystal bulks.The results indicate that SCF is dominated by the void size,while void depth and stress level play secondary roles.The SCF fluctuates by the orientation differences among grains and increases with increasing the size of the void.Finally,based on sensitivity examination of orientations and configurations of grains sur-rounding the void,an empirical multivariable-coupled formula is proposed to assess SCF near voids considering anisotropy,and the presented model is in good agreement with the simulation results.
基金supported by the National Natural Science Foundation of China(42302160)the Sanya City Science and Technology Innovation Project(2022KJCX51)the Support Plan for Outstanding Youth Innovation Team in Shandong Higher Education Institutions(2022KJ060).
文摘The microscopic occurrence characteristics primarily constrain the enrichment and mobility of shale oil.This study collected the lacustrine shales from the Palaeogene Funing Formation in the Gaoyou Sag, Subei Basin. Conventional and multistage Rock-Eval, scanning electron microscopy, and nuclear magnetic resonance(NMR) T1-T2were performed to analyze the contents and occurrence characteristics of shale oil. Low-temperature nitrogen adsorption-desorption(LTNA/D) experiments were conducted on the shales before and after extraction. The relationships between shale oil occurrence with organic matter and pore structures were then discussed. Predominantly, the shale oil in the Funing Formation is found within fractures, with secondary occurrences in interparticle pores linked to brittle minerals and sizeable intraparticle pores associated with clay minerals. The selected shales can be categorized into two types based on the nitrogen isotherms. Type A shales are characterized by high contents of felsic and calcareous minerals but low clay minerals, with larger TOC and shale oil values. Conversely, Type B shales are marked by abundant clay minerals but diminished TOC and shale oil contents. The lower BET specific surface area(SSA), larger average pore diameter, and simpler pore surfaces and pore structures lead to the Type A shales being more conducive to shale oil enrichment and mobility. Shale oil content is predominantly governed by the abundance of organic matter, while an overabundance of organic matter typically equates to a reduced ratio of free oil and diminished fluidity. The BET SSA, volumes of pores less than 25 and 100 nm at extracted state all correlate negatively with total and adsorbed oil contents but display no correlation with free oil, while they have positive relationships with capillary-bound water.Consequently, pore water is mainly saturated in micropores(<25 nm) and minipores(25-100 nm), as well as adsorbed oil, while free oil, i.e., bound and movable oil, primarily exists in mesopores(100-1000 nm) and macropores(>1000 nm). These findings may enhance the understanding of the microscopic occurrence characteristics of shale oil and will contribute to guide resource estimation and shale oil sweet spot exploitation in the Gaoyou Sag, Subei Basin.
