Improving the accuracy of anthropogenic volatile organic compounds(VOCs)emission inventory is crucial for reducing atmospheric pollution and formulating control policy of air pollution.In this study,an anthropogenic s...Improving the accuracy of anthropogenic volatile organic compounds(VOCs)emission inventory is crucial for reducing atmospheric pollution and formulating control policy of air pollution.In this study,an anthropogenic speciated VOCs emission inventory was established for Central China represented by Henan Province at a 3 km×3 km spatial resolution based on the emission factormethod.The 2019 VOCs emission in Henan Provincewas 1003.5 Gg,while industrial process source(33.7%)was the highest emission source,Zhengzhou(17.9%)was the city with highest emission and April and August were the months with the more emissions.High VOCs emission regions were concentrated in downtown areas and industrial parks.Alkanes and aromatic hydrocarbons were the main VOCs contribution groups.The species composition,source contribution and spatial distribution were verified and evaluated through tracer ratio method(TR),Positive Matrix Factorization Model(PMF)and remote sensing inversion(RSI).Results show that both the emission results by emission inventory(EI)(15.7 Gg)and by TRmethod(13.6 Gg)and source contribution by EI and PMF are familiar.The spatial distribution of HCHO primary emission based on RSI is basically consistent with that of HCHO emission based on EI with a R-value of 0.73.The verification results show that the VOCs emission inventory and speciated emission inventory established in this study are relatively reliable.展开更多
Metal Additive Manufacturing(MAM) technology has become an important means of rapid prototyping precision manufacturing of special high dynamic heterogeneous complex parts. In response to the micromechanical defects s...Metal Additive Manufacturing(MAM) technology has become an important means of rapid prototyping precision manufacturing of special high dynamic heterogeneous complex parts. In response to the micromechanical defects such as porosity issues, significant deformation, surface cracks, and challenging control of surface morphology encountered during the selective laser melting(SLM) additive manufacturing(AM) process of specialized Micro Electromechanical System(MEMS) components, multiparameter optimization and micro powder melt pool/macro-scale mechanical properties control simulation of specialized components are conducted. The optimal parameters obtained through highprecision preparation and machining of components and static/high dynamic verification are: laser power of 110 W, laser speed of 600 mm/s, laser diameter of 75 μm, and scanning spacing of 50 μm. The density of the subordinate components under this reference can reach 99.15%, the surface hardness can reach 51.9 HRA, the yield strength can reach 550 MPa, the maximum machining error of the components is 4.73%, and the average surface roughness is 0.45 μm. Through dynamic hammering and high dynamic firing verification, SLM components meet the requirements for overload resistance. The results have proven that MEM technology can provide a new means for the processing of MEMS components applied in high dynamic environments. The parameters obtained in the conclusion can provide a design basis for the additive preparation of MEMS components.展开更多
The exponential growth of the Internet of Things(IoT)has revolutionized various domains such as healthcare,smart cities,and agriculture,generating vast volumes of data that require secure processing and storage in clo...The exponential growth of the Internet of Things(IoT)has revolutionized various domains such as healthcare,smart cities,and agriculture,generating vast volumes of data that require secure processing and storage in cloud environments.However,reliance on cloud infrastructure raises critical security challenges,particularly regarding data integrity.While existing cryptographic methods provide robust integrity verification,they impose significant computational and energy overheads on resource-constrained IoT devices,limiting their applicability in large-scale,real-time scenarios.To address these challenges,we propose the Cognitive-Based Integrity Verification Model(C-BIVM),which leverages Belief-Desire-Intention(BDI)cognitive intelligence and algebraic signatures to enable lightweight,efficient,and scalable data integrity verification.The model incorporates batch auditing,reducing resource consumption in large-scale IoT environments by approximately 35%,while achieving an accuracy of over 99.2%in detecting data corruption.C-BIVM dynamically adapts integrity checks based on real-time conditions,optimizing resource utilization by minimizing redundant operations by more than 30%.Furthermore,blind verification techniques safeguard sensitive IoT data,ensuring privacy compliance by preventing unauthorized access during integrity checks.Extensive experimental evaluations demonstrate that C-BIVM reduces computation time for integrity checks by up to 40%compared to traditional bilinear pairing-based methods,making it particularly suitable for IoT-driven applications in smart cities,healthcare,and beyond.These results underscore the effectiveness of C-BIVM in delivering a secure,scalable,and resource-efficient solution tailored to the evolving needs of IoT ecosystems.展开更多
Most existing multi-pattern matching algorithms are designed for single English texts leading to issues such as missed matches and space expansion when applied to Chinese-English mixed-text environments.The Hash Trie-...Most existing multi-pattern matching algorithms are designed for single English texts leading to issues such as missed matches and space expansion when applied to Chinese-English mixed-text environments.The Hash Trie-based matching machine demonstrates strong compatibility with both Chinese and English,ensuring high accuracy in text processing and subtree positioning.In this study,a novel functional framework based on the HashTrie structure is proposed and mechanically verified using Isabelle/HOL.This framework is applied to design Functional Multi-Pattern Matching(FMPM),the first functional multi-pattern matching algorithm for Chinese-English mixed texts.FMPM constructs the HashTrie matching machine using character codes and threads the machine according to the associations between pattern strings.The experimental results show that as the stored string information increases,the proposed algorithm demonstrates more significant optimization in retrieval efficiency.FMPM simplifies the implementation of the Threaded Hash Trie(THT)for Chinese-English mixed texts,effectively reducing the uncertainties in the transition from the algorithm description to code implementation.FMPM addresses the problem of space explosion Chinese-English mixed texts and avoids issues such as bound variable iteration errors.The functional framework of the HashTrie structure serves as a reference for the formal verification of future HashTrie-based algorithms.展开更多
Kinship verification is a key biometric recognition task that determines biological relationships based on physical features.Traditional methods predominantly use facial recognition,leveraging established techniques a...Kinship verification is a key biometric recognition task that determines biological relationships based on physical features.Traditional methods predominantly use facial recognition,leveraging established techniques and extensive datasets.However,recent research has highlighted ear recognition as a promising alternative,offering advantages in robustness against variations in facial expressions,aging,and occlusions.Despite its potential,a significant challenge in ear-based kinship verification is the lack of large-scale datasets necessary for training deep learning models effectively.To address this challenge,we introduce the EarKinshipVN dataset,a novel and extensive collection of ear images designed specifically for kinship verification.This dataset consists of 4876 high-resolution color images from 157 multiracial families across different regions,forming 73,220 kinship pairs.EarKinshipVN,a diverse and large-scale dataset,advances kinship verification research using ear features.Furthermore,we propose the Mixer Attention Inception(MAI)model,an improved architecture that enhances feature extraction and classification accuracy.The MAI model fuses Inceptionv4 and MLP Mixer,integrating four attention mechanisms to enhance spatial and channel-wise feature representation.Experimental results demonstrate that MAI significantly outperforms traditional backbone architectures.It achieves an accuracy of 98.71%,surpassing Vision Transformer models while reducing computational complexity by up to 95%in parameter usage.These findings suggest that ear-based kinship verification,combined with an optimized deep learning model and a comprehensive dataset,holds significant promise for biometric applications.展开更多
Smart learning environments have been considered as vital sources and essential needs in modern digital education systems.With the rapid proliferation of smart and assistive technologies,smart learning processes have ...Smart learning environments have been considered as vital sources and essential needs in modern digital education systems.With the rapid proliferation of smart and assistive technologies,smart learning processes have become quite convenient,comfortable,and financially affordable.This shift has led to the emergence of pervasive computing environments,where user’s intelligent behavior is supported by smart gadgets;however,it is becoming more challenging due to inconsistent behavior of Artificial intelligence(AI)assistive technologies in terms of networking issues,slow user responses to technologies and limited computational resources.This paper presents a context-aware predictive reasoning based formalism for smart learning environments that facilitates students in managing their academic as well as extra-curricular activities autonomously with limited human intervention.This system consists of a three-tier architecture including the acquisition of the contextualized information from the environment autonomously,modeling the system using Web Ontology Rule Language(OWL 2 RL)and Semantic Web Rule Language(SWRL),and perform reasoning to infer the desired goals whenever and wherever needed.For contextual reasoning,we develop a non-monotonic reasoning based formalism to reason with contextual information using rule-based reasoning.The focus is on distributed problem solving,where context-aware agents exchange information using rule-based reasoning and specify constraints to accomplish desired goals.To formally model-check and simulate the system behavior,we model the case study of a smart learning environment in the UPPAAL model checker and verify the desired properties in the model,such as safety,liveness and robust properties to reflect the overall correctness behavior of the system with achieving the minimum analysis time of 0.002 s and 34,712 KB memory utilization.展开更多
This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification metho...This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification methodology for practical implementation of vision-based navigation technology on the microsatellite platform.Firstly,a low power consumption,light weight,and high performance vision-based relative navigation optical sensor is designed.Subsequently,a set of ground verification system is designed for the hardware-in-the-loop testing of the vision-based relative navigation systems.Finally,the designed vision-based relative navigation optical sensor and the proposed angles-only navigation algorithms are tested on the ground verification system.The results verify that the optical simulator after geometrical calibration can meet the requirements of the hardware-in-the-loop testing of vision-based relative navigation systems.Based on experimental results,the relative position accuracy of the angles-only navigation filter at terminal time is increased by 25.5%,and the relative speed accuracy is increased by 31.3% compared with those of optical simulator before geometrical calibration.展开更多
Cold stress widely impairs the quality and yield of tea plants. The miR164 family and its target NAC transcription factor have been identified as crucial regulators in response to cold stress. However, the role of miR...Cold stress widely impairs the quality and yield of tea plants. The miR164 family and its target NAC transcription factor have been identified as crucial regulators in response to cold stress. However, the role of miR164 and CsNAC in cold tolerance in tea plants was little understood. In our study, the expression level of CsMIR164a was significantly reduced under cold stress and significantly and negatively correlated with that of CsNAC1.5' RACE and GUS histochemical assays showed that CsNAC1 was cleaved by CsMIR164a. The CsMIR164a-silenced tea leaves promoted the expression levels of CsNAC1 and CsCBFs and exhibited greater cold tolerance. Also, the overexpression of CsNAC1 enhanced cold tolerance in transgenic Arabidopsis plants by promoting the expression levels of AtCBFs. In contrast, the heterologous overexpression of CsMIR164a in Arabidopsis decreased the expression level of AtNACs and AtCBFs and thus impaired cold tolerance. Additionally, silencing of CsNAC1 impaired the expression levels of CsCBFs, resulting in greater cold sensitivity in tea leaves. Our present study demonstrated that the miR164a-CsNAC1 module may play a negative role in the cold tolerance of tea plants via the CsCBF-dependent pathway.展开更多
Karst caves are among the most common and critical geological hazards in karst regions.Due to their marked differences in physical properties compared to the surrounding rock,they can be detected using various geophys...Karst caves are among the most common and critical geological hazards in karst regions.Due to their marked differences in physical properties compared to the surrounding rock,they can be detected using various geophysical techniques.Karsts have developed on the surface of the Qingshuitang Wollastonite Mining Area in Huangtian Town,Hezhou City,Guangxi Province.In line with mine safety production requirements,a professional assessment of the potential development of karst caves must be conducted within 150 m of the mining area’s surface.Following an on-site investiga-tion and comparison with traditional geophysical methods,seismic frequency resonance technology(Seismic FRT)was selected for detection due to its convenience,flexibility,cost-effectiveness,and rapid data acquisition capabilities.Contour maps of the apparent wave impedance and geological profiles along the survey lines were obtained through data collection and processing.In combination with surface karst and mining geology,32 karst caves(hidden danger points)and 15 karst development zones were identified.Drilling verification was conducted at the A428 and B122 anomalous points on the A1# and B1# survey lines.The verification results were consistent with the inferred depths and maximum apparent wave impedance anomalies,confirming that Seismic FRT is a feasible and effective method for detecting hid-den karst development areas in mines.展开更多
With the evolution of next-generation communication networks,ensuring robust Core Network(CN)architecture and data security has become paramount.This paper addresses critical vulnerabilities in the architecture of CN ...With the evolution of next-generation communication networks,ensuring robust Core Network(CN)architecture and data security has become paramount.This paper addresses critical vulnerabilities in the architecture of CN and data security by proposing a novel framework based on blockchain technology that is specifically designed for communication networks.Traditional centralized network architectures are vulnerable to Distributed Denial of Service(DDoS)attacks,particularly in roaming scenarios where there is also a risk of private data leakage,which imposes significant operational demands.To address these issues,we introduce the Blockchain-Enhanced Core Network Architecture(BECNA)and the Secure Decentralized Identity Authentication Scheme(SDIDAS).The BECNA utilizes blockchain technology to decentralize data storage,enhancing network security,stability,and reliability by mitigating Single Points of Failure(SPoF).The SDIDAS utilizes Decentralized Identity(DID)technology to secure user identity data and streamline authentication in roaming scenarios,significantly reducing the risk of data breaches during cross-network transmissions.Our framework employs Ethereum,free5GC,Wireshark,and UERANSIM tools to create a robust,tamper-evident system model.A comprehensive security analysis confirms substantial improvements in user privacy and network security.Simulation results indicate that our approach enhances communication CNs security and reliability,while also ensuring data security.展开更多
Verification and validation(V&V)is a helpful tool for evaluating simulation errors,but its application in unsteady cavitating flow remains a challenging issue due to the difficulty in meeting the requirement of an...Verification and validation(V&V)is a helpful tool for evaluating simulation errors,but its application in unsteady cavitating flow remains a challenging issue due to the difficulty in meeting the requirement of an asymptotic range.Hence,a new V&V approach for large eddy simulation(LES)is proposed.This approach offers a viable solution for the error estimation of simulation data that are unable to satisfy the asymptotic range.The simulation errors of cavitating flow around a projectile near the free surface are assessed using the new V&V method.The evident error values are primarily dispersed around the cavity region and free surface.The increasingly intense cavitating flow increases the error magnitudes.In addition,the modeling error magnitudes of the Dynamic Smagorinsky-Lilly model are substantially smaller than that of the Smagorinsky-Lilly model.The present V&V method can capture the decrease in the modeling errors due to model enhancements,further exhibiting its applicability in cavitating flow simulations.Moreover,the monitoring points where the simulation data are beyond the asymptotic range are primarily dispersed near the cavity region,and the number of such points grows as the cavitating flow intensifies.The simulation outcomes also suggest that the re-entrant jet and shedding cavity collapse are the chief sources of vorticity motions,which remarkably affect the simulation accuracy.The results of this study provide a valuable reference for V&V research.展开更多
In the foundry industries,process design has traditionally relied on manuals and complex theoretical calculations.With the advent of 3D design in casting,computer-aided design(CAD)has been applied to integrate the fea...In the foundry industries,process design has traditionally relied on manuals and complex theoretical calculations.With the advent of 3D design in casting,computer-aided design(CAD)has been applied to integrate the features of casting process,thereby expanding the scope of design options.These technologies use parametric model design techniques for rapid component creation and use databases to access standard process parameters and design specifications.However,3D models are currently still created through inputting or calling parameters,which requires numerous verifications through calculations to ensure the design rationality.This process may be significantly slowed down due to repetitive modifications and extended design time.As a result,there are increasingly urgent demands for a real-time verification mechanism to address this issue.Therefore,this study proposed a novel closed-loop model and software development method that integrated contextual design with real-time verification,dynamically verifying relevant rules for designing 3D casting components.Additionally,the study analyzed three typical closed-loop scenarios of agile design in an independent developed intelligent casting process system.It is believed that foundry industries can potentially benefit from favorably reduced design cycles to yield an enhanced competitive product market.展开更多
The Outer Space Treaty(OST)remains a cornerstone of international space law,enshrining the principle of peaceful use for celestial bodies.However,ambiguities in its provisions,particularly regarding military activitie...The Outer Space Treaty(OST)remains a cornerstone of international space law,enshrining the principle of peaceful use for celestial bodies.However,ambiguities in its provisions,particularly regarding military activities and dual-use technologies,pose significant challenges in the 21st century.This paper examines the treaty’s limitations in addressing modern space militarization,commercial-military convergence,and resource exploitation.It critiques the lack of robust verification mechanisms and proposes clarifications to ensure sustainable and cooperative space exploration.The analysis highlights the urgent need for updated legal frameworks to govern private actors and emerging technologies while preserving the OST’s foundational principles.The paper evaluates recent policy initiatives to enhance space weapons regulations,including the Russo-Chinese treaty proposal to ban space-based weapons and the EU’s International Code of Conduct for Space.It concludes existing provisions indicate a reluctance to limit nuclear weapons in space,but are a milestone in regulating the arms race’s expansion.However,ambiguities persist regarding prohibited activities.展开更多
At present,AI is reshaping the global industrial landscape at an unprecedented depth.As the cornerstone suppor ting technological innovation and industrial development,metrology is radiating new vitality in the AI era...At present,AI is reshaping the global industrial landscape at an unprecedented depth.As the cornerstone suppor ting technological innovation and industrial development,metrology is radiating new vitality in the AI era.It is not only a verification scale for algorithm accuracy and a trust anchor for sensing systems,but also a strategic link for China and ASEAN to deepen industrial collaboration.Metrology runs through the entire innovation chain of AI,providing verifiable and reproducible scientific basis for technological innovation and industrial development.展开更多
BACKGROUND Xuanshen decoction(XSD)is a traditional Chinese medicine formulation that is often applied in treating slow transit constipation(STC).However,its specific therapeutic mechanism remains to be characterized.A...BACKGROUND Xuanshen decoction(XSD)is a traditional Chinese medicine formulation that is often applied in treating slow transit constipation(STC).However,its specific therapeutic mechanism remains to be characterized.AIM To investigate the mechanism of XSD for STC,we combined network pharmacology prediction,molecular docking analysis,and in vivo studies.METHODS The therapeutic effects of XSD on loperamide-induced STC in rats were assessed through 24-hour fecal number,fecal moisture content,and intestinal propelling rate.Hematoxylin–eosin and Alcian blue/periodic acid-Schiff staining were applied to analyze colonic mucosa for histopathological presentation and mucin production.Next,the mechanism of action of XSD for STC was elucidated through network pharmacology and molecular docking analyses,and the findings were validated by the animal experiments.RESULTS XSD significantly alleviated the symptoms of STC in rats.Relative to the STC rats,in the medium-dose XSD and high-dose XSD rats,stem cell factor,C-kit,phosphophosphoinositide 3-kinase/phosphoinositide 3-kinase,phospho-protein kinase B/protein kinase B,catalase,and superoxide dismutase were substantially upregulated(P<0.01);nuclear factor erythroid 2-related factor 2(nuclear/cytoplasmic)and B-cell lymphoma 2(Bcl-2)were increased(P<0.05),while cleaved caspase-3,Bcl-2-associated X protein(Bax)/Bcl-2,and malondialdehyde were significantly reduced(P<0.01).Heme oxygenase-1 and glutathione peroxidase in the high-dose XSD group were significantly increased(P<0.01),and Bax was statistically lowered(P<0.01);glutathione peroxidase in the medium-dose XSD group was increased(P<0.05),while Bax was reduced(P<0.05).CONCLUSION XSD may inhibit oxidative-stress-induced apoptosis in interstitial cells of Cajal by stimulating the phosphoinositide 3-kinase/protein kinase B/nuclear factor erythroid 2-related factor 2 pathway,thereby effectively treating STC.展开更多
Low-frequency signals have been proven valuable in the fields of target detection and geological exploration.Nevertheless,the practical implementation of these signals is hindered by large antenna diameters,limiting t...Low-frequency signals have been proven valuable in the fields of target detection and geological exploration.Nevertheless,the practical implementation of these signals is hindered by large antenna diameters,limiting their potential applications.Therefore,it is imperative to study the creation of lowfrequency signals using antennas with suitable dimensions.In contrast to conventional mechanical antenna techniques,our study generates low-frequency signals in the spatial domain utilizing the principle of the Doppler effect.We also defines the antenna array architecture,the timing sequency,and the radiating element signal waveform,and provides experimental prototypes including 8/64 antennas based on earlier research.In the conducted experiments,121 MHz,40 MHz,and 10 kHz composite signals are generated by 156 MHz radiating element signals.The composite signal spectrum matches the simulations,proving our low-frequency signal generating method works.This holds significant implications for research on generating low-frequency signals with small-sized antennas.展开更多
systematic verification and validation(V&V)of our previously proposed momentum source wave generation method is performed.Some settings of previous numerical wave tanks(NWTs)of regular and irregular waves have bee...systematic verification and validation(V&V)of our previously proposed momentum source wave generation method is performed.Some settings of previous numerical wave tanks(NWTs)of regular and irregular waves have been optimized.The H2-5 V&V method involving five mesh sizes with mesh refinement ratio being 1.225 is used to verify the NWT of regular waves,in which the wave height and mass conservation are mainly considered based on a Lv3(H s=0.75 m)and a Lv6(H s=5 m)regular wave.Additionally,eight different sea states are chosen to validate the wave height,mass conservation and wave frequency of regular waves.Regarding the NWT of irregular waves,five different sea states with significant wave heights ranging from 0.09 m to 12.5 m are selected to validate the statistical characteristics of irregular waves,including the profile of the wave spectrum,peak frequency and significant wave height.Results show that the verification errors for Lv3 and Lv6 regular wave on the most refined grid are−0.018 and−0.35 for wave height,respectively,and−0.14 and for−0.17 mass conservation,respectively.The uncertainty estimation analysis shows that the numerical error could be partially balanced out by the modelling error to achieve a smaller validation error by adjusting the mesh size elaborately.And the validation errors of the wave height,mass conservation and dominant frequency of regular waves under different sea states are no more than 7%,8% and 2%,respectively.For a Lv3(H_(s)=0.75 m)and a Lv6(H_(s)=5 m)regular wave,simulations are validated on the wave height in wave development section for safety factors FS≈1 and FS≈0.5-1,respectively.Regarding irregular waves,the validation errors of the significant wave height and peak frequency are both lower than 2%.展开更多
Combining the characteristics of the course“Comprehensive Training of E-Commerce Live Streaming,”this paper embeds the CDIO(Conceive-Design-Implement-Operate)method into the live streaming training process,carries o...Combining the characteristics of the course“Comprehensive Training of E-Commerce Live Streaming,”this paper embeds the CDIO(Conceive-Design-Implement-Operate)method into the live streaming training process,carries out the virtual scene“e-commerce live streaming”course design and project-based teaching reform that integrates teaching training with learning effects,and establishes a set of cross-professional student live streaming training procedures guided by the CDIO engineering method.The training results show that the CDIO practical teaching model supported by data feedback plays an important role and significance in improving students’learning effects,and also provides some new experiences for integrating engineering thinking into the construction of new liberal arts.展开更多
The growing demand for international travel has highlighted the critical need for reliable tools to verify travelers’healthcare status and meet entry requirements.Personal health passports,while essential,face signif...The growing demand for international travel has highlighted the critical need for reliable tools to verify travelers’healthcare status and meet entry requirements.Personal health passports,while essential,face significant challenges related to data silos,privacy protection,and forgery risks in global sharing.To address these issues,this study proposes a blockchain-based solution designed for the secure storage,sharing,and verification of personal health passports.This innovative approach combines on-chain and off-chain storage,leveraging searchable encryption to enhance data security and optimize blockchain storage efficiency.By reducing the storage burden on the blockchain,the system ensures both the secure handling and reliable sharing of sensitive personal health data.An optimized consensus mechanism streamlines the process into two stages,minimizing communication complexity among nodes and significantly improving the throughput of the blockchain system.Additionally,the introduction of advanced aggregate signature technology accommodates multi-user scenarios,reducing computational overhead for signature verification and enabling swift identification ofmalicious forgers.Comprehensive security analyses validate the system’s robustness and reliability.Simulation results demonstrate notable performance improvements over existing solutions,with reductions in computational overhead of up to 49.89%and communication overhead of up to 25.81%inmulti-user scenarios.Furthermore,the optimized consensus mechanism shows substantial efficiency gains across varying node configurations.This solution represents a significant step toward addressing the pressing challenges of health passport management in a secure,scalable,and efficient manner.展开更多
Pneumatic down-the-hole hammer, serving as rock-breaking tool, possesses appeal for directional drilling due to its high rate of penetration. However, corresponding experimental studies on existing hammers for directi...Pneumatic down-the-hole hammer, serving as rock-breaking tool, possesses appeal for directional drilling due to its high rate of penetration. However, corresponding experimental studies on existing hammers for directional drilling have rarely been reported, and a model for evaluating their output performance is absent. This study proposes a novel structure of self-rotating pneumatic hammer(NSH)with a built-in rotational mechanism, which converts partial impact energy of the piston to rotate the drill bit and, consequently, enables dual functions of impact and rotate drill bit. The energy is converted via a screw key-groove mechanism, and the wedge-shaped teeth mechanism ensures that the drill bit rotates clockwise during the piston moves downward. The computational fluid dynamics method is applied to simulate the dynamic response of airflow and piston during the operation of Φ127NSH.Meanwhile, a test bench is established to record data concerning chamber pressure and piston displacement, as well as recording its operational status and rock fragmentation during drilling into granite. The results showed that the maximum error between simulated and experimental data is 8.2%.The Φ127NSH successfully achieves dual impact and rotary drilling functions, and granite smoothly feeds and forms a continuous shear rock zone. In addition, the effects of torque load, engagement distance in rotation sleeves, and well deviation angle towards the performance of NSH were studied in detail. The designed Φ127NSH operates at an impact velocity of 3.98 m/s, impact frequency of 12.55 Hz, and rotational speed of 29.51 r/min under a mass-flow rate of 0.18 kg/s, torque load of 400 N·m, engagement distance of 40 mm, and well deviation angle of 0°. The torque load adversely affects the NSH output performance. Increasing the engagement distance improves impact performance while reducing rotational performance. The performance variation of the NSH is minimal when drilling directional wells with varying deviation angles.展开更多
基金supported by Zhengzhou PM_(2.5)and O_(3)Collaborative Control and Monitoring Project(No.20220347A)the 2020 National Supercomputing Zhengzhou Center Innovation Ecosystem Construction Technology Project(No.201400210700).
文摘Improving the accuracy of anthropogenic volatile organic compounds(VOCs)emission inventory is crucial for reducing atmospheric pollution and formulating control policy of air pollution.In this study,an anthropogenic speciated VOCs emission inventory was established for Central China represented by Henan Province at a 3 km×3 km spatial resolution based on the emission factormethod.The 2019 VOCs emission in Henan Provincewas 1003.5 Gg,while industrial process source(33.7%)was the highest emission source,Zhengzhou(17.9%)was the city with highest emission and April and August were the months with the more emissions.High VOCs emission regions were concentrated in downtown areas and industrial parks.Alkanes and aromatic hydrocarbons were the main VOCs contribution groups.The species composition,source contribution and spatial distribution were verified and evaluated through tracer ratio method(TR),Positive Matrix Factorization Model(PMF)and remote sensing inversion(RSI).Results show that both the emission results by emission inventory(EI)(15.7 Gg)and by TRmethod(13.6 Gg)and source contribution by EI and PMF are familiar.The spatial distribution of HCHO primary emission based on RSI is basically consistent with that of HCHO emission based on EI with a R-value of 0.73.The verification results show that the VOCs emission inventory and speciated emission inventory established in this study are relatively reliable.
基金funded by the National Natural Science Foundation of China Youth Fund(Grant No.62304022)Science and Technology on Electromechanical Dynamic Control Laboratory(China,Grant No.6142601012304)the 2022e2024 China Association for Science and Technology Innovation Integration Association Youth Talent Support Project(Grant No.2022QNRC001).
文摘Metal Additive Manufacturing(MAM) technology has become an important means of rapid prototyping precision manufacturing of special high dynamic heterogeneous complex parts. In response to the micromechanical defects such as porosity issues, significant deformation, surface cracks, and challenging control of surface morphology encountered during the selective laser melting(SLM) additive manufacturing(AM) process of specialized Micro Electromechanical System(MEMS) components, multiparameter optimization and micro powder melt pool/macro-scale mechanical properties control simulation of specialized components are conducted. The optimal parameters obtained through highprecision preparation and machining of components and static/high dynamic verification are: laser power of 110 W, laser speed of 600 mm/s, laser diameter of 75 μm, and scanning spacing of 50 μm. The density of the subordinate components under this reference can reach 99.15%, the surface hardness can reach 51.9 HRA, the yield strength can reach 550 MPa, the maximum machining error of the components is 4.73%, and the average surface roughness is 0.45 μm. Through dynamic hammering and high dynamic firing verification, SLM components meet the requirements for overload resistance. The results have proven that MEM technology can provide a new means for the processing of MEMS components applied in high dynamic environments. The parameters obtained in the conclusion can provide a design basis for the additive preparation of MEMS components.
基金supported by King Saud University,Riyadh,Saudi Arabia,through Researchers Supporting Project number RSP2025R498.
文摘The exponential growth of the Internet of Things(IoT)has revolutionized various domains such as healthcare,smart cities,and agriculture,generating vast volumes of data that require secure processing and storage in cloud environments.However,reliance on cloud infrastructure raises critical security challenges,particularly regarding data integrity.While existing cryptographic methods provide robust integrity verification,they impose significant computational and energy overheads on resource-constrained IoT devices,limiting their applicability in large-scale,real-time scenarios.To address these challenges,we propose the Cognitive-Based Integrity Verification Model(C-BIVM),which leverages Belief-Desire-Intention(BDI)cognitive intelligence and algebraic signatures to enable lightweight,efficient,and scalable data integrity verification.The model incorporates batch auditing,reducing resource consumption in large-scale IoT environments by approximately 35%,while achieving an accuracy of over 99.2%in detecting data corruption.C-BIVM dynamically adapts integrity checks based on real-time conditions,optimizing resource utilization by minimizing redundant operations by more than 30%.Furthermore,blind verification techniques safeguard sensitive IoT data,ensuring privacy compliance by preventing unauthorized access during integrity checks.Extensive experimental evaluations demonstrate that C-BIVM reduces computation time for integrity checks by up to 40%compared to traditional bilinear pairing-based methods,making it particularly suitable for IoT-driven applications in smart cities,healthcare,and beyond.These results underscore the effectiveness of C-BIVM in delivering a secure,scalable,and resource-efficient solution tailored to the evolving needs of IoT ecosystems.
基金Supported by the National Natural Science Foundation of China(62462036,62462037)Jiangxi Provincial Natural Science Foundation(20242BAB26017,20232BAB202010)+1 种基金Cultivation Project for Academic and Technical Leader in Major Disciplines in Jiangxi Province(20232BCJ22013)the Jiangxi Province Graduate Innovation Found Project(YC2024-S214)。
文摘Most existing multi-pattern matching algorithms are designed for single English texts leading to issues such as missed matches and space expansion when applied to Chinese-English mixed-text environments.The Hash Trie-based matching machine demonstrates strong compatibility with both Chinese and English,ensuring high accuracy in text processing and subtree positioning.In this study,a novel functional framework based on the HashTrie structure is proposed and mechanically verified using Isabelle/HOL.This framework is applied to design Functional Multi-Pattern Matching(FMPM),the first functional multi-pattern matching algorithm for Chinese-English mixed texts.FMPM constructs the HashTrie matching machine using character codes and threads the machine according to the associations between pattern strings.The experimental results show that as the stored string information increases,the proposed algorithm demonstrates more significant optimization in retrieval efficiency.FMPM simplifies the implementation of the Threaded Hash Trie(THT)for Chinese-English mixed texts,effectively reducing the uncertainties in the transition from the algorithm description to code implementation.FMPM addresses the problem of space explosion Chinese-English mixed texts and avoids issues such as bound variable iteration errors.The functional framework of the HashTrie structure serves as a reference for the formal verification of future HashTrie-based algorithms.
文摘Kinship verification is a key biometric recognition task that determines biological relationships based on physical features.Traditional methods predominantly use facial recognition,leveraging established techniques and extensive datasets.However,recent research has highlighted ear recognition as a promising alternative,offering advantages in robustness against variations in facial expressions,aging,and occlusions.Despite its potential,a significant challenge in ear-based kinship verification is the lack of large-scale datasets necessary for training deep learning models effectively.To address this challenge,we introduce the EarKinshipVN dataset,a novel and extensive collection of ear images designed specifically for kinship verification.This dataset consists of 4876 high-resolution color images from 157 multiracial families across different regions,forming 73,220 kinship pairs.EarKinshipVN,a diverse and large-scale dataset,advances kinship verification research using ear features.Furthermore,we propose the Mixer Attention Inception(MAI)model,an improved architecture that enhances feature extraction and classification accuracy.The MAI model fuses Inceptionv4 and MLP Mixer,integrating four attention mechanisms to enhance spatial and channel-wise feature representation.Experimental results demonstrate that MAI significantly outperforms traditional backbone architectures.It achieves an accuracy of 98.71%,surpassing Vision Transformer models while reducing computational complexity by up to 95%in parameter usage.These findings suggest that ear-based kinship verification,combined with an optimized deep learning model and a comprehensive dataset,holds significant promise for biometric applications.
基金supported by the National Research Foundation(NRF),Republic of Korea,under project BK21 FOUR(4299990213939).
文摘Smart learning environments have been considered as vital sources and essential needs in modern digital education systems.With the rapid proliferation of smart and assistive technologies,smart learning processes have become quite convenient,comfortable,and financially affordable.This shift has led to the emergence of pervasive computing environments,where user’s intelligent behavior is supported by smart gadgets;however,it is becoming more challenging due to inconsistent behavior of Artificial intelligence(AI)assistive technologies in terms of networking issues,slow user responses to technologies and limited computational resources.This paper presents a context-aware predictive reasoning based formalism for smart learning environments that facilitates students in managing their academic as well as extra-curricular activities autonomously with limited human intervention.This system consists of a three-tier architecture including the acquisition of the contextualized information from the environment autonomously,modeling the system using Web Ontology Rule Language(OWL 2 RL)and Semantic Web Rule Language(SWRL),and perform reasoning to infer the desired goals whenever and wherever needed.For contextual reasoning,we develop a non-monotonic reasoning based formalism to reason with contextual information using rule-based reasoning.The focus is on distributed problem solving,where context-aware agents exchange information using rule-based reasoning and specify constraints to accomplish desired goals.To formally model-check and simulate the system behavior,we model the case study of a smart learning environment in the UPPAAL model checker and verify the desired properties in the model,such as safety,liveness and robust properties to reflect the overall correctness behavior of the system with achieving the minimum analysis time of 0.002 s and 34,712 KB memory utilization.
基金supported in part by the Doctoral Initiation Fund of Nanchang Hangkong University(No.EA202403107)Jiangxi Province Early Career Youth Science and Technology Talent Training Project(No.CK202403509).
文摘This paper presents the design and ground verification for vision-based relative navigation systems of microsatellites,which offers a comprehensive hardware design solution and a robust experimental verification methodology for practical implementation of vision-based navigation technology on the microsatellite platform.Firstly,a low power consumption,light weight,and high performance vision-based relative navigation optical sensor is designed.Subsequently,a set of ground verification system is designed for the hardware-in-the-loop testing of the vision-based relative navigation systems.Finally,the designed vision-based relative navigation optical sensor and the proposed angles-only navigation algorithms are tested on the ground verification system.The results verify that the optical simulator after geometrical calibration can meet the requirements of the hardware-in-the-loop testing of vision-based relative navigation systems.Based on experimental results,the relative position accuracy of the angles-only navigation filter at terminal time is increased by 25.5%,and the relative speed accuracy is increased by 31.3% compared with those of optical simulator before geometrical calibration.
基金supported by the Anhui University Collaborative Innovation Project, China (GXXT-2020080)the Scientific Research Project of Anhui Provincial Colleges and Universities, China (2023AH040136)。
文摘Cold stress widely impairs the quality and yield of tea plants. The miR164 family and its target NAC transcription factor have been identified as crucial regulators in response to cold stress. However, the role of miR164 and CsNAC in cold tolerance in tea plants was little understood. In our study, the expression level of CsMIR164a was significantly reduced under cold stress and significantly and negatively correlated with that of CsNAC1.5' RACE and GUS histochemical assays showed that CsNAC1 was cleaved by CsMIR164a. The CsMIR164a-silenced tea leaves promoted the expression levels of CsNAC1 and CsCBFs and exhibited greater cold tolerance. Also, the overexpression of CsNAC1 enhanced cold tolerance in transgenic Arabidopsis plants by promoting the expression levels of AtCBFs. In contrast, the heterologous overexpression of CsMIR164a in Arabidopsis decreased the expression level of AtNACs and AtCBFs and thus impaired cold tolerance. Additionally, silencing of CsNAC1 impaired the expression levels of CsCBFs, resulting in greater cold sensitivity in tea leaves. Our present study demonstrated that the miR164a-CsNAC1 module may play a negative role in the cold tolerance of tea plants via the CsCBF-dependent pathway.
基金supported by the General Project of Guangxi Natural Science Foundation grant number[2020GXNSFAA297088]the Hezhou Science Research and Development Plan Project grant number[2024143]the Basic Research Ability Enhancement Project for Young and Middle-aged Teachers at Guangxi Universities grant number[2024KY1877].
文摘Karst caves are among the most common and critical geological hazards in karst regions.Due to their marked differences in physical properties compared to the surrounding rock,they can be detected using various geophysical techniques.Karsts have developed on the surface of the Qingshuitang Wollastonite Mining Area in Huangtian Town,Hezhou City,Guangxi Province.In line with mine safety production requirements,a professional assessment of the potential development of karst caves must be conducted within 150 m of the mining area’s surface.Following an on-site investiga-tion and comparison with traditional geophysical methods,seismic frequency resonance technology(Seismic FRT)was selected for detection due to its convenience,flexibility,cost-effectiveness,and rapid data acquisition capabilities.Contour maps of the apparent wave impedance and geological profiles along the survey lines were obtained through data collection and processing.In combination with surface karst and mining geology,32 karst caves(hidden danger points)and 15 karst development zones were identified.Drilling verification was conducted at the A428 and B122 anomalous points on the A1# and B1# survey lines.The verification results were consistent with the inferred depths and maximum apparent wave impedance anomalies,confirming that Seismic FRT is a feasible and effective method for detecting hid-den karst development areas in mines.
基金supported by the Beijing Natural Science Foundation(L223025,4242003)Qin Xin Talents Cultivation Program of Beijing Information Science&Technology University(QXTCP B202405)。
文摘With the evolution of next-generation communication networks,ensuring robust Core Network(CN)architecture and data security has become paramount.This paper addresses critical vulnerabilities in the architecture of CN and data security by proposing a novel framework based on blockchain technology that is specifically designed for communication networks.Traditional centralized network architectures are vulnerable to Distributed Denial of Service(DDoS)attacks,particularly in roaming scenarios where there is also a risk of private data leakage,which imposes significant operational demands.To address these issues,we introduce the Blockchain-Enhanced Core Network Architecture(BECNA)and the Secure Decentralized Identity Authentication Scheme(SDIDAS).The BECNA utilizes blockchain technology to decentralize data storage,enhancing network security,stability,and reliability by mitigating Single Points of Failure(SPoF).The SDIDAS utilizes Decentralized Identity(DID)technology to secure user identity data and streamline authentication in roaming scenarios,significantly reducing the risk of data breaches during cross-network transmissions.Our framework employs Ethereum,free5GC,Wireshark,and UERANSIM tools to create a robust,tamper-evident system model.A comprehensive security analysis confirms substantial improvements in user privacy and network security.Simulation results indicate that our approach enhances communication CNs security and reliability,while also ensuring data security.
基金Supported by the National Key R&D Program of China(2022YFB3303501)the National Natural Science Foundation of China(Project Nos.52176041 and 12102308)the Fundamental Research Funds for the Central Universities(Project Nos.2042023kf0208 and 2042023kf0159).
文摘Verification and validation(V&V)is a helpful tool for evaluating simulation errors,but its application in unsteady cavitating flow remains a challenging issue due to the difficulty in meeting the requirement of an asymptotic range.Hence,a new V&V approach for large eddy simulation(LES)is proposed.This approach offers a viable solution for the error estimation of simulation data that are unable to satisfy the asymptotic range.The simulation errors of cavitating flow around a projectile near the free surface are assessed using the new V&V method.The evident error values are primarily dispersed around the cavity region and free surface.The increasingly intense cavitating flow increases the error magnitudes.In addition,the modeling error magnitudes of the Dynamic Smagorinsky-Lilly model are substantially smaller than that of the Smagorinsky-Lilly model.The present V&V method can capture the decrease in the modeling errors due to model enhancements,further exhibiting its applicability in cavitating flow simulations.Moreover,the monitoring points where the simulation data are beyond the asymptotic range are primarily dispersed near the cavity region,and the number of such points grows as the cavitating flow intensifies.The simulation outcomes also suggest that the re-entrant jet and shedding cavity collapse are the chief sources of vorticity motions,which remarkably affect the simulation accuracy.The results of this study provide a valuable reference for V&V research.
基金the financial support of the Natural Science Foundation of Hubei Province,China (Grant No.2022CFB770)。
文摘In the foundry industries,process design has traditionally relied on manuals and complex theoretical calculations.With the advent of 3D design in casting,computer-aided design(CAD)has been applied to integrate the features of casting process,thereby expanding the scope of design options.These technologies use parametric model design techniques for rapid component creation and use databases to access standard process parameters and design specifications.However,3D models are currently still created through inputting or calling parameters,which requires numerous verifications through calculations to ensure the design rationality.This process may be significantly slowed down due to repetitive modifications and extended design time.As a result,there are increasingly urgent demands for a real-time verification mechanism to address this issue.Therefore,this study proposed a novel closed-loop model and software development method that integrated contextual design with real-time verification,dynamically verifying relevant rules for designing 3D casting components.Additionally,the study analyzed three typical closed-loop scenarios of agile design in an independent developed intelligent casting process system.It is believed that foundry industries can potentially benefit from favorably reduced design cycles to yield an enhanced competitive product market.
文摘The Outer Space Treaty(OST)remains a cornerstone of international space law,enshrining the principle of peaceful use for celestial bodies.However,ambiguities in its provisions,particularly regarding military activities and dual-use technologies,pose significant challenges in the 21st century.This paper examines the treaty’s limitations in addressing modern space militarization,commercial-military convergence,and resource exploitation.It critiques the lack of robust verification mechanisms and proposes clarifications to ensure sustainable and cooperative space exploration.The analysis highlights the urgent need for updated legal frameworks to govern private actors and emerging technologies while preserving the OST’s foundational principles.The paper evaluates recent policy initiatives to enhance space weapons regulations,including the Russo-Chinese treaty proposal to ban space-based weapons and the EU’s International Code of Conduct for Space.It concludes existing provisions indicate a reluctance to limit nuclear weapons in space,but are a milestone in regulating the arms race’s expansion.However,ambiguities persist regarding prohibited activities.
文摘At present,AI is reshaping the global industrial landscape at an unprecedented depth.As the cornerstone suppor ting technological innovation and industrial development,metrology is radiating new vitality in the AI era.It is not only a verification scale for algorithm accuracy and a trust anchor for sensing systems,but also a strategic link for China and ASEAN to deepen industrial collaboration.Metrology runs through the entire innovation chain of AI,providing verifiable and reproducible scientific basis for technological innovation and industrial development.
基金Supported by the 2024 Hospital Innovation Talent Cultivation Fund Project,No.2024YGKT12.
文摘BACKGROUND Xuanshen decoction(XSD)is a traditional Chinese medicine formulation that is often applied in treating slow transit constipation(STC).However,its specific therapeutic mechanism remains to be characterized.AIM To investigate the mechanism of XSD for STC,we combined network pharmacology prediction,molecular docking analysis,and in vivo studies.METHODS The therapeutic effects of XSD on loperamide-induced STC in rats were assessed through 24-hour fecal number,fecal moisture content,and intestinal propelling rate.Hematoxylin–eosin and Alcian blue/periodic acid-Schiff staining were applied to analyze colonic mucosa for histopathological presentation and mucin production.Next,the mechanism of action of XSD for STC was elucidated through network pharmacology and molecular docking analyses,and the findings were validated by the animal experiments.RESULTS XSD significantly alleviated the symptoms of STC in rats.Relative to the STC rats,in the medium-dose XSD and high-dose XSD rats,stem cell factor,C-kit,phosphophosphoinositide 3-kinase/phosphoinositide 3-kinase,phospho-protein kinase B/protein kinase B,catalase,and superoxide dismutase were substantially upregulated(P<0.01);nuclear factor erythroid 2-related factor 2(nuclear/cytoplasmic)and B-cell lymphoma 2(Bcl-2)were increased(P<0.05),while cleaved caspase-3,Bcl-2-associated X protein(Bax)/Bcl-2,and malondialdehyde were significantly reduced(P<0.01).Heme oxygenase-1 and glutathione peroxidase in the high-dose XSD group were significantly increased(P<0.01),and Bax was statistically lowered(P<0.01);glutathione peroxidase in the medium-dose XSD group was increased(P<0.05),while Bax was reduced(P<0.05).CONCLUSION XSD may inhibit oxidative-stress-induced apoptosis in interstitial cells of Cajal by stimulating the phosphoinositide 3-kinase/protein kinase B/nuclear factor erythroid 2-related factor 2 pathway,thereby effectively treating STC.
基金Science and Technology Project of Aerospace Information Research Institute,Chinese Academy of Sciences(Y910340Z2F)Science and Technology Project of BBEF(E3E2010201)。
文摘Low-frequency signals have been proven valuable in the fields of target detection and geological exploration.Nevertheless,the practical implementation of these signals is hindered by large antenna diameters,limiting their potential applications.Therefore,it is imperative to study the creation of lowfrequency signals using antennas with suitable dimensions.In contrast to conventional mechanical antenna techniques,our study generates low-frequency signals in the spatial domain utilizing the principle of the Doppler effect.We also defines the antenna array architecture,the timing sequency,and the radiating element signal waveform,and provides experimental prototypes including 8/64 antennas based on earlier research.In the conducted experiments,121 MHz,40 MHz,and 10 kHz composite signals are generated by 156 MHz radiating element signals.The composite signal spectrum matches the simulations,proving our low-frequency signal generating method works.This holds significant implications for research on generating low-frequency signals with small-sized antennas.
基金supported by the National Key R&D Program of China(Grant No.2022YFB3303500).
文摘systematic verification and validation(V&V)of our previously proposed momentum source wave generation method is performed.Some settings of previous numerical wave tanks(NWTs)of regular and irregular waves have been optimized.The H2-5 V&V method involving five mesh sizes with mesh refinement ratio being 1.225 is used to verify the NWT of regular waves,in which the wave height and mass conservation are mainly considered based on a Lv3(H s=0.75 m)and a Lv6(H s=5 m)regular wave.Additionally,eight different sea states are chosen to validate the wave height,mass conservation and wave frequency of regular waves.Regarding the NWT of irregular waves,five different sea states with significant wave heights ranging from 0.09 m to 12.5 m are selected to validate the statistical characteristics of irregular waves,including the profile of the wave spectrum,peak frequency and significant wave height.Results show that the verification errors for Lv3 and Lv6 regular wave on the most refined grid are−0.018 and−0.35 for wave height,respectively,and−0.14 and for−0.17 mass conservation,respectively.The uncertainty estimation analysis shows that the numerical error could be partially balanced out by the modelling error to achieve a smaller validation error by adjusting the mesh size elaborately.And the validation errors of the wave height,mass conservation and dominant frequency of regular waves under different sea states are no more than 7%,8% and 2%,respectively.For a Lv3(H_(s)=0.75 m)and a Lv6(H_(s)=5 m)regular wave,simulations are validated on the wave height in wave development section for safety factors FS≈1 and FS≈0.5-1,respectively.Regarding irregular waves,the validation errors of the significant wave height and peak frequency are both lower than 2%.
基金phased research achievement of the Major Project of Philosophy and Social Sciences Research in Jiangsu Universities“Research on the Intervention Mechanism of Short Video Addiction”(2024SJZD145)。
文摘Combining the characteristics of the course“Comprehensive Training of E-Commerce Live Streaming,”this paper embeds the CDIO(Conceive-Design-Implement-Operate)method into the live streaming training process,carries out the virtual scene“e-commerce live streaming”course design and project-based teaching reform that integrates teaching training with learning effects,and establishes a set of cross-professional student live streaming training procedures guided by the CDIO engineering method.The training results show that the CDIO practical teaching model supported by data feedback plays an important role and significance in improving students’learning effects,and also provides some new experiences for integrating engineering thinking into the construction of new liberal arts.
文摘The growing demand for international travel has highlighted the critical need for reliable tools to verify travelers’healthcare status and meet entry requirements.Personal health passports,while essential,face significant challenges related to data silos,privacy protection,and forgery risks in global sharing.To address these issues,this study proposes a blockchain-based solution designed for the secure storage,sharing,and verification of personal health passports.This innovative approach combines on-chain and off-chain storage,leveraging searchable encryption to enhance data security and optimize blockchain storage efficiency.By reducing the storage burden on the blockchain,the system ensures both the secure handling and reliable sharing of sensitive personal health data.An optimized consensus mechanism streamlines the process into two stages,minimizing communication complexity among nodes and significantly improving the throughput of the blockchain system.Additionally,the introduction of advanced aggregate signature technology accommodates multi-user scenarios,reducing computational overhead for signature verification and enabling swift identification ofmalicious forgers.Comprehensive security analyses validate the system’s robustness and reliability.Simulation results demonstrate notable performance improvements over existing solutions,with reductions in computational overhead of up to 49.89%and communication overhead of up to 25.81%inmulti-user scenarios.Furthermore,the optimized consensus mechanism shows substantial efficiency gains across varying node configurations.This solution represents a significant step toward addressing the pressing challenges of health passport management in a secure,scalable,and efficient manner.
基金supported by the Natural Science Foundation of Jilin Province(YDZJ202101ZYTS143).
文摘Pneumatic down-the-hole hammer, serving as rock-breaking tool, possesses appeal for directional drilling due to its high rate of penetration. However, corresponding experimental studies on existing hammers for directional drilling have rarely been reported, and a model for evaluating their output performance is absent. This study proposes a novel structure of self-rotating pneumatic hammer(NSH)with a built-in rotational mechanism, which converts partial impact energy of the piston to rotate the drill bit and, consequently, enables dual functions of impact and rotate drill bit. The energy is converted via a screw key-groove mechanism, and the wedge-shaped teeth mechanism ensures that the drill bit rotates clockwise during the piston moves downward. The computational fluid dynamics method is applied to simulate the dynamic response of airflow and piston during the operation of Φ127NSH.Meanwhile, a test bench is established to record data concerning chamber pressure and piston displacement, as well as recording its operational status and rock fragmentation during drilling into granite. The results showed that the maximum error between simulated and experimental data is 8.2%.The Φ127NSH successfully achieves dual impact and rotary drilling functions, and granite smoothly feeds and forms a continuous shear rock zone. In addition, the effects of torque load, engagement distance in rotation sleeves, and well deviation angle towards the performance of NSH were studied in detail. The designed Φ127NSH operates at an impact velocity of 3.98 m/s, impact frequency of 12.55 Hz, and rotational speed of 29.51 r/min under a mass-flow rate of 0.18 kg/s, torque load of 400 N·m, engagement distance of 40 mm, and well deviation angle of 0°. The torque load adversely affects the NSH output performance. Increasing the engagement distance improves impact performance while reducing rotational performance. The performance variation of the NSH is minimal when drilling directional wells with varying deviation angles.
