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Relationships between femoral strength evaluated by nonlinear finite element analysis and BMD,material distribution and geometric morphology
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作者 He Gong1,Linwei Lv1,Rui Zhang1,Dong Zhu3,Ming Zhang2(1.Department of Engineering Mechanics,Jilin University,Changchun 130025,P.R.China 2.Department of Health Technology and Informatics,The Hong Kong Polytechnic University,Hong Kong,China 3.Department of Orthopedic Surgery,No.1 Hospital,Jilin University,Changchun 130021,China) 《医用生物力学》 EI CAS CSCD 2009年第S1期66-66,共1页
Precisely quantifying the strength of the proximal femur and accurately assessing hip fracture risk would enable those at high risk to be identified so that preventive interventions could be taken.Development of bette... Precisely quantifying the strength of the proximal femur and accurately assessing hip fracture risk would enable those at high risk to be identified so that preventive interventions could be taken.Development of better measures of femoral strength using the clinically 展开更多
关键词 BMD Relationships between femoral strength evaluated by nonlinear finite element analysis and BMD material distribution and geometric morphology FEA
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Comparison of GUF and Monte Carlo methods to evaluate task-specific uncertainty in laser tracker measurement 被引量:1
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作者 杨景照 李国喜 +2 位作者 吴宝中 龚京忠 王杰 《Journal of Central South University》 SCIE EI CAS 2014年第10期3793-3804,共12页
Measurement uncertainty plays an important role in laser tracking measurement analyses. In the present work, the guides to the expression of uncertainty in measurement(GUM) uncertainty framework(GUF) and its supplemen... Measurement uncertainty plays an important role in laser tracking measurement analyses. In the present work, the guides to the expression of uncertainty in measurement(GUM) uncertainty framework(GUF) and its supplement, the Monte Carlo method, were used to estimate the uncertainty of task-specific laser tracker measurements. First, the sources of error in laser tracker measurement were analyzed in detail, including instruments, measuring network fusion, measurement strategies, measurement process factors(such as the operator), measurement environment, and task-specific data processing. Second, the GUM and Monte Carlo methods and their application to laser tracker measurement were presented. Finally, a case study involving the uncertainty estimation of a cylindricity measurement process using the GUF and Monte Carlo methods was illustrated. The expanded uncertainty results(at 95% confidence levels) obtained with the Monte Carlo method are 0.069 mm(least-squares criterion) and 0.062 mm(minimum zone criterion), respectively, while with the GUM uncertainty framework, none but the result of least-squares criterion can be got, which is 0.071 mm. Thus, the GUM uncertainty framework slightly underestimates the overall uncertainty by 10%. The results demonstrate that the two methods have different characteristics in task-specific uncertainty evaluations of laser tracker measurements. The results indicate that the Monte Carlo method is a practical tool for applying the principle of propagation of distributions and does not depend on the assumptions and limitations required by the law of propagation of uncertainties(GUF). These features of the Monte Carlo method reduce the risk of an unreliable measurement of uncertainty estimation, particularly in cases of complicated measurement models, without the need to evaluate partial derivatives. In addition, the impact of sampling strategy and evaluation method on the uncertainty of the measurement results can also be taken into account with Monte Carlo method, which plays a guiding role in measurement planning. 展开更多
关键词 task-specific uncertainty laser tracker measurement uncertainty evaluation Monte Carlo method uncertainy framework(GUF)
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Combing the Entropy Weight Method with Fuzzy Mathematics for Assessing the Quality and Post-Ripening Mechanism of High-Temperature Daqu during Storage 被引量:1
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作者 YANG Junlin YANG Shaojuan +8 位作者 WU Cheng YIN Yanshun YOU Xiaolong ZHAO Wenyu ZHU Anran WANG Jia HU Feng HU Jianfeng WANG Diqiang 《食品科学》 北大核心 2025年第9期48-62,共15页
This study investigated the physicochemical properties,enzyme activities,volatile flavor components,microbial communities,and sensory evaluation of high-temperature Daqu(HTD)during the maturation process,and a standar... This study investigated the physicochemical properties,enzyme activities,volatile flavor components,microbial communities,and sensory evaluation of high-temperature Daqu(HTD)during the maturation process,and a standard system was established for comprehensive quality evaluation of HTD.There were obvious changes in the physicochemical properties,enzyme activities,and volatile flavor components at different storage periods,which affected the sensory evaluation of HTD to a certain extent.The results of high-throughput sequencing revealed significant microbial diversity,and showed that the bacterial community changed significantly more than did the fungal community.During the storage process,the dominant bacterial genera were Kroppenstedtia and Thermoascus.The correlation between dominant microorganisms and quality indicators highlighted their role in HTD quality.Lactococcus,Candida,Pichia,Paecilomyces,and protease activity played a crucial role in the formation of isovaleraldehyde.Acidic protease activity had the greatest impact on the microbial community.Moisture promoted isobutyric acid generation.Furthermore,the comprehensive quality evaluation standard system was established by the entropy weight method combined with multi-factor fuzzy mathematics.Consequently,this study provides innovative insights for comprehensive quality evaluation of HTD during storage and establishes a groundwork for scientific and rational storage of HTD and quality control of sauce-flavor Baijiu. 展开更多
关键词 microbial community high-temperature Daqu comprehensive quality evaluation entropy weight method maturation process
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Performance analysis of scramjet including magnetohydrodynamic power generation after combustor
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作者 LIU Chenyuan WU Shaoxun MENG Hao 《推进技术》 北大核心 2025年第8期15-28,共14页
To investigate the overall performance of reverse energy bypass scramjet,firstly a variable spe⁃cific heat method combined with a chemical balance calculation module for combustion products were used to es⁃tablish a b... To investigate the overall performance of reverse energy bypass scramjet,firstly a variable spe⁃cific heat method combined with a chemical balance calculation module for combustion products were used to es⁃tablish a benchmark scramjet performance evaluation model.Based on the test data of typical flying point of Mach 7 with the altitude of 29 km,the reliability of the model was verified.The deviations of parameters such as the to⁃tal pressure loss of combustor between the model and the test data were analyzed.Furtherly,an analytical method for post-combustion magnetohydrodynamic power generation was established;by embedding the above method into the overall performance evaluation model,performance prediction considering the power generation effect was realized.Finally,based on the above model,variety regulations of the inlet and the outlet parameters of the power generation channel and performance parameters including the engine specific impulse and the unit thrust under different enthalpy extraction ratios and load factors were analyzed.It could be concluded that the model can reliably predict the variations of key parameters.As the value of the load factor increases,the value of the conduc⁃tivity required to reach the specified enthalpy extraction ratio first decreases and then increases,which is approxi⁃mately parabolic.In order to reduce the demand for the gas conductivity for MHD power generation,the load fac⁃tor should be around 0.5.When the load factor is 0.4 and the magnetic induction intensity is 2.5 T,if the enthalpy extraction ratio reaches 0.5%,the engine specific impulse performance reduces about 3.58%. 展开更多
关键词 SCRAMJET Energy bypass Magnetohydrodynamic power generation Chemical balance Performance evaluation
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Prediction Method of Polar Navigation Window Period Based on Risk Evaluation
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作者 JIANG Jia−qi SHI Gui−jie WANG De−yu 《船舶力学》 北大核心 2025年第6期986-999,共14页
With the increase of international trade activities and the gradual melting of the polar ice cap,the importance of the Arctic route for marine transportation has been emphasized.Prediction of the polar navigation wind... With the increase of international trade activities and the gradual melting of the polar ice cap,the importance of the Arctic route for marine transportation has been emphasized.Prediction of the polar navigation window period is crucial for navigating in the Arctic route,which is of great significance to the selection of the route and the optimization of navigation.This paper introduces the establishment of a risk index system,determination of risk index weight,establishment of a risk evaluation model,and prediction algorithm for the window period.In addition,data sources of both environmental factors and ship factors are introducted,and their shortcomings are analyzed,followed by introduction of various methods involved in window prediction and analysis of their advantages and disadvantages.The quantitative risk evaluation and window period algorithm can provide a reference for the research of polar navigation window period prediction. 展开更多
关键词 window period risk evaluation polar navigation risk index
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Evaluation of restoration effects for city walls based on terahertz-infrared integrated technology
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作者 MENG Tian-hua ZHAO Guo-zhong +3 位作者 XU Shi-xiang ZHANG Hai-jiao LI Bang-quan HU Wei-dong 《中国光学(中英文)》 北大核心 2025年第4期954-967,共14页
To scientifically evaluate the restoration performance of ancient city walls,Terahertz time-domain spectroscopy(THz-TDS)and infrared thermal imaging technology were applied to assess the Desheng Fortress(Ming Dynasty)... To scientifically evaluate the restoration performance of ancient city walls,Terahertz time-domain spectroscopy(THz-TDS)and infrared thermal imaging technology were applied to assess the Desheng Fortress(Ming Dynasty).Three representative sections were examined:adobe brick masonry repaired(Area 1),well-preserved original(Area 2),and layer-by-layer ramming repaired(Area 3).THz spectral data revealed significant differences between Area 1(time delay:3.72 ps;refractive index:2.224)and Area 2(time delay:3.02 ps;refractive index:2.107),while Area 3(time delay:3.12 ps;refractive index:2.098)demonstrated nearly identical THz spectral data to Area 2.Infrared thermal imaging also showed that the Area 3 restored by layer-by-layer ramming exhibited greater uniformity with fewer instances of cracks,capillary phenomena,or biological diseases.The proposed point-surface integrated evaluation methodology synergistically combines infrared thermography mapping of heritage surfaces with THz spectral datasets acquired through in-situ micro-sampling,enabling quantitative restoration assessment and providing a novel approach for scientifically validating traditional conservation techniques. 展开更多
关键词 nondestructive testing cultural relic restoration performance evaluation high sensitivity
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LuoFuShan Rheumatism Plaster ameliorates s neuropathicpain in mice by suppressing TLR4/TNF-αsignaling
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作者 FU Yufang TAN Weiling +3 位作者 LI Xiaocui LIN Rongtian LIU Shuwen YE Ling 《南方医科大学学报》 北大核心 2025年第11期2285-2296,共12页
Objective To explore the therapeutic effect of LuoFuShan Rheumatism Plaster(LFS)on neuropathic pain(NP)and its molecular mechanism.Methods Mouse models of sciatic nerve chronic constriction injury(CCI)were treated wit... Objective To explore the therapeutic effect of LuoFuShan Rheumatism Plaster(LFS)on neuropathic pain(NP)and its molecular mechanism.Methods Mouse models of sciatic nerve chronic constriction injury(CCI)were treated with low,medium,and high doses(2.2,4.4,and 8.8 cm2,respectively)of LFS by topical application for 14 consecutive days.The therapeutic effects were assessed by evaluating the mechanical withdrawal threshold(MWT),paw withdrawal latency(PWL),plasma IL-6 and TNF-αlevels,and histopathology of the sciatic nerve.Network pharmacology and molecular docking were used to identify the key targets and signaling pathways.The key targets were verified by RT-qPCR and immunohistochemistry.The biosafety of LFS was evaluated by measuring the organ indices and damage indicators of the heart,liver,and kidneys.Results Compared with the CCI group,LFS dose-dependently increased MWT and PWL,reduced plasma IL-6 and TNF-αlevels,and alleviated sciatic nerve inflammation in the mouse models.Network pharmacology identified 378 bioactive compounds targeting 279 NPassociated genes enriched in TLR and TNF signaling.Molecular docking showed that quercetin and ursolic acid in LFS could stably bind to TLR4 and TNF-α.In the mouse models of sciatic nerve CCI,LFS significantly downregulated the mRNA expression levels of Tlr4 and Tnf-αin the spinal cord in a dose-dependent manner and lowered the protein expressions of TLR4 and TNF-αin the sciatic nerve.LFS treatment did not cause significant changes in the organ indices or damage indicators of the heart,liver and kidneys as compared with those in the CCI model group and sham-operated group.Conclusion LFS alleviates NP in mice by suppression of TLR4/TNF-α-mediated neuroinflammation with a good safety profile. 展开更多
关键词 LuoFuShan Rheumatism Plaster neuropathic pain TLR4/TNF-αsignaling Safety evaluation
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Evaluation of transgenic cotton lines expressing an insecticidal fern protein against whitefly,Bemisia tabaci(Gennadius)
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作者 KUMAR Rishi NAGRARE V.S. +14 位作者 SHAH Vivek SINGH Satnam PANDHER Suneet SINGH Satpal VERMA S.K. PAUL Debashis RATHORE Pankaj SHUKLA Anoop Kumar SINGH Mithlesh Kumar SAURABH Sharad KUMAR Harish KAUR Rupinderjeet SINGH Pradhyumna Kumar WAGHMARE V.N. PRASAD Y.G. 《Journal of Cotton Research》 2025年第2期163-177,共15页
Background Transgenic research in crops involves using genetic engineering techniques to introduce specific genes of interest from other organisms,or even entirely new genes into plant genomes to create crops with des... Background Transgenic research in crops involves using genetic engineering techniques to introduce specific genes of interest from other organisms,or even entirely new genes into plant genomes to create crops with desirable traits that wouldn’t be possible through conventional breeding methods.Transgenic crops have been developed for various traits globally.Whitefly,Bemisia tabaci(Gennadius)is one of the major sucking pests of cotton that cause significant damage to the cotton production.To combat whitefly infestations,researchers have developed four transgenic cotton lines expressing the fern protein.And those transgenic lines need to be evaluated for their performance against the target pest—whitefly.The evaluation was designed as controlled trials in polyhouse or muslin cloth cages under open-choice and no-choice conditions by comparing four transgenic cotton lines(A,B,C,and D)with three control groups,including untransformed cotton plants with a same genetic background of the transgenic line,conventionally bred whitefly-resistant cotton,and whitefly-susceptible cotton.In order to study the generational effect,the evaluation also involved studies on whitefly development in laboratory,muslin cloth cage,and polyhouse conditions.Results Both open-choice and no-choice experiments had shown that all the four transgenic cotton lines(A,B,C,and D)expressing the fern protein reduced adult whitefly numbers significantly compared with the control lines,except for the no-choice conditions in 2021,where the transgenic line C was non-significant different from the resistant control line.Notably,the nymphal population on the resistant control line was relatively low and nonsignificant different from the transgenic line C in 2021;and the transgenic lines A and C in 2022 under open-choice conditions.Under no-choice condition,the nymphal counts in the resistant control line was non-significant different from transgenic lines C and D in 2021;and transgenic line D in 2022.All transgenic lines showed significant decrease in egg hatching in 2021 and nymphal development in 2022,except for the transgenic line C which had no significant different in the nymphal development comparing with non-transgenic control lines in 2022.Adult emergence rates in both years of evaluation showed significant decrease in transgenic lines A and B comparing with the control lines.Additionally,the results showed a significant reduction in cotton leaf curl disease and sooty mold development in all the four transgenic lines compared with susceptible control under open-choice conditions,indicating potential benefits of transgenic lines beyond direct effect on whitefly control.Furthermore,the research explored the generational effects of the fern protein on whitefly which revealed the lowest fecundity in the transgenic line C across F0,F1 and F3 generations,lower egg hatching in F1 and F2 generations in transgenic lines A and B,shorter nymphal duration in F1 and F2 generations in transgenic line B,and the least total adult emergence in the transgenic line C in F0 and F3 generations.Conclusions These findings suggest that the transgenic cotton lines expressing fern protein disrupts whitefly populations and the life cycle to a certain extent.However,results are not consistent over generations and years of study,indicating these transgenic lines were not superior over control lines and need to be improved in future breeding. 展开更多
关键词 EVALUATION Fern protein Transgenic cotton lines WHITEFLY
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Ballistic response mechanism and resistance-driven evaluation method of UHMWPE composite
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作者 Yemao He Johnny Qing Zhou +3 位作者 Yanan Jiao Hongshuai Lei Zeang Zhao Daining Fang 《Defence Technology(防务技术)》 2025年第2期1-16,共16页
The use of ultra-high molecular weight polyethylene(UHMWPE)composite in the design of lightweight protective equipment,has gained a lot of interest.However,there is an urgent need to understand the ballistic response ... The use of ultra-high molecular weight polyethylene(UHMWPE)composite in the design of lightweight protective equipment,has gained a lot of interest.However,there is an urgent need to understand the ballistic response mechanism and theoretical prediction model of performance.This paper explores the ballistic response mechanism of UHMWPE composite through experimental and simulation analyses.Then,a resistance-driven modeling method was proposed to establish a theoretical model for predicting the bulletproof performance.The ballistic response mechanism of UHMWPE composite encompassed three fundamental modes:local response,structural response,and coupled response.The occurrence ratio of these fundamental response modes during impact was dependent on the projectile velocity and laminate thickness.The bulletproof performance of laminate under different response modes was assessed based on the penetration depth of the projectile,the bulging height on the rear face of the laminate,the thickness of remaining sub-laminate,and residual velocity of the projectile.The absolute deviations of bulletproof performance indicator between theoretical value and experimental value were well within 11.13%,demonstrating that the established evaluation model possessed high degree of prediction accuracy. 展开更多
关键词 UHMWPE composite Ballistic response mechanism Theoretical model Performance evaluation
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Brittleness evaluation of gas-bearing coal based on statistical damage constitution model and energy evolution mechanism
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作者 XUE Yi WANG Lin-chao +5 位作者 LIU Yong RANJITH P G CAO Zheng-zheng SHI Xu-yang GAO Feng KONG Hai-ling 《Journal of Central South University》 2025年第2期566-581,共16页
Accurate assessment of coal brittleness is crucial in the design of coal seam drilling and underground coal mining operations.This study proposes a method for evaluating the brittleness of gas-bearing coal based on a ... Accurate assessment of coal brittleness is crucial in the design of coal seam drilling and underground coal mining operations.This study proposes a method for evaluating the brittleness of gas-bearing coal based on a statistical damage constitutive model and energy evolution mechanisms.Initially,integrating the principle of effective stress and the Hoek-Brown criterion,a statistical damage constitutive model for gas-bearing coal is established and validated through triaxial compression tests under different gas pressures to verify its accuracy and applicability.Subsequently,employing energy evolution mechanism,two energy characteristic parameters(elastic energy proportion and dissipated energy proportion)are analyzed.Based on the damage stress thresholds,the damage evolution characteristics of gas bearing coal were explored.Finally,by integrating energy characteristic parameters with damage parameters,a novel brittleness index is proposed.The results demonstrate that the theoretical curves derived from the statistical damage constitutive model closely align with the test curves,accurately reflecting the stress−strain characteristics of gas-bearing coal and revealing the stress drop and softening characteristics of coal in the post-peak stage.The shape parameter and scale parameter represent the brittleness and macroscopic strength of the coal,respectively.As gas pressure increases from 1 to 5 MPa,the shape parameter and the scale parameter decrease by 22.18%and 60.45%,respectively,indicating a reduction in both brittleness and strength of the coal.Parameters such as maximum damage rate and peak elastic energy storage limit positively correlate with coal brittleness.The brittleness index effectively captures the brittleness characteristics and reveals a decrease in brittleness and an increase in sensitivity to plastic deformation under higher gas pressure conditions. 展开更多
关键词 gas pressure statistical damage constitutive model energy evolution mechanism brittleness evaluation gas bearing coal
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Air-to-ground reconnaissance-attack task allocation for heterogeneous UAV swarm
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作者 LUO Yuelong JIANG Xiuqiang +1 位作者 ZHONG Suchuan JI Yuandong 《Journal of Systems Engineering and Electronics》 2025年第1期155-175,共21页
A task allocation problem for the heterogeneous unmanned aerial vehicle (UAV) swarm in unknown environments is studied in this paper.Considering that the actual mission environment information may be unknown,the UAV s... A task allocation problem for the heterogeneous unmanned aerial vehicle (UAV) swarm in unknown environments is studied in this paper.Considering that the actual mission environment information may be unknown,the UAV swarm needs to detect the environment first and then attack the detected targets.The heterogeneity of UAVs,multiple types of tasks,and the dynamic nature of task environment lead to uneven load and time sequence problems.This paper proposes an improved contract net protocol (CNP) based task allocation scheme,which effectively balances the load of UAVs and improves the task efficiency.Firstly,two types of task models are established,including regional reconnaissance tasks and target attack tasks.Secondly,for regional reconnaissance tasks,an improved CNP algorithm using the uncertain contract is developed.Through uncertain contracts,the area size of the regional reconnaissance task is determined adaptively after this task assignment,which can improve reconnaissance efficiency and resource utilization.Thirdly,for target attack tasks,an improved CNP algorithm using the fuzzy integrated evaluation and the double-layer negotiation is presented to enhance collaborative attack efficiency through adjusting the assignment sequence adaptively and multi-layer allocation.Finally,the effectiveness and advantages of the improved method are verified through comparison simulations. 展开更多
关键词 unmanned aerial vehicle(UAV)swarm reconnaissance-attack coupled task allocation contract net protocol(CNP) fuzzy integrated evaluation double-layer negotiation
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基于节点评估与最大类间方差的孤立森林异常值检测 被引量:1
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作者 严爱军 和世潇 汤健 《北京工业大学学报》 CAS CSCD 北大核心 2024年第10期1188-1197,共10页
针对孤立森林(isolation forest, iForest)无法有效检测局部异常值且异常值分数阈值难以精确设定的问题,提出一种基于节点评估(node evaluation, NE)与最大类间方差(Otsu)的iForest异常值检测方法。首先,在样本评估过程中将节点深度与... 针对孤立森林(isolation forest, iForest)无法有效检测局部异常值且异常值分数阈值难以精确设定的问题,提出一种基于节点评估(node evaluation, NE)与最大类间方差(Otsu)的iForest异常值检测方法。首先,在样本评估过程中将节点深度与相对质量同时引入评分机制,使算法对全局和局部异常值敏感;然后,为了准确设定分数阈值,采用Otsu自适应设定异常值分数阈值;最后,在不同数据集上验证所提方法的有效性。实验结果表明,该方法可以有效兼顾全局和局部异常值的检测,提高iForest检测异常值的准确性。 展开更多
关键词 孤立森林(isolation forest iForest) 异常值检测 最大类间方差(Otsu) 节点评估(node evaluation NE) 分数阈值 节点深度
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A review of rockburst:Insights from engineering sites to theoretical investigations 被引量:3
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作者 HE Ben-guo WANG Biao +2 位作者 FENG Xia-ting ZHANG Heng-yuan JIN Zhao-tong 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第8期2607-2643,共37页
Rockburst has perennially posed a formidable challenge to the stability of underground engineering works,particularly under conditions of deep-seated high stress.This paper provides a comprehensive review of recent ad... Rockburst has perennially posed a formidable challenge to the stability of underground engineering works,particularly under conditions of deep-seated high stress.This paper provides a comprehensive review of recent advancements in on-site research related to rockburst occurrences,covering on-site case analyses,monitoring methodologies,early warning systems,and risk(proneness)evaluation.Initially,the concepts and classifications of rockburst based on on-site understanding were summarized.The influences of structural planes(in various spatial distribution combinations),in-situ stress(particularly magnitude and direction of the principal stress),dynamic disturbances,and excavation profiles on rockburst were thoroughly assessed and discussed through the analysis of published rockburst cases and on-site survey results.Subsequently,a compendium of commonly employed on-site monitoring techniques was outlined,delineating their respective technical attributes.Particular emphasis is accorded to the efficacy of microseismic monitoring technology and its prospective utility in facilitating dynamic rockburst early warning mechanisms.Building upon this foundation,the feasibility of assessing rockburst propensity while considering on-site variables is verified,encompassing the selection and quantitative evaluation of pertinent indicators.Ultimately,a comprehensive synthesis of the paper is presented,alongside the articulation of prospective research goals for the future. 展开更多
关键词 ROCKBURST in-situ stress structural plane dynamic disturbance rockburst proneness evaluation
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Risk assessment of rockburst using SMOTE oversampling and integration algorithms under GBDT framework 被引量:2
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作者 WANG Jia-chuang DONG Long-jun 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第8期2891-2915,共25页
Rockburst is a common geological disaster in underground engineering,which seriously threatens the safety of personnel,equipment and property.Utilizing machine learning models to evaluate risk of rockburst is graduall... Rockburst is a common geological disaster in underground engineering,which seriously threatens the safety of personnel,equipment and property.Utilizing machine learning models to evaluate risk of rockburst is gradually becoming a trend.In this study,the integrated algorithms under Gradient Boosting Decision Tree(GBDT)framework were used to evaluate and classify rockburst intensity.First,a total of 301 rock burst data samples were obtained from a case database,and the data were preprocessed using synthetic minority over-sampling technique(SMOTE).Then,the rockburst evaluation models including GBDT,eXtreme Gradient Boosting(XGBoost),Light Gradient Boosting Machine(LightGBM),and Categorical Features Gradient Boosting(CatBoost)were established,and the optimal hyperparameters of the models were obtained through random search grid and five-fold cross-validation.Afterwards,use the optimal hyperparameter configuration to fit the evaluation models,and analyze these models using test set.In order to evaluate the performance,metrics including accuracy,precision,recall,and F1-score were selected to analyze and compare with other machine learning models.Finally,the trained models were used to conduct rock burst risk assessment on rock samples from a mine in Shanxi Province,China,and providing theoretical guidance for the mine's safe production work.The models under the GBDT framework perform well in the evaluation of rockburst levels,and the proposed methods can provide a reliable reference for rockburst risk level analysis and safety management. 展开更多
关键词 rockburst evaluation SMOTE oversampling random search grid K-fold cross-validation confusion matrix
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Experimental investigation of spectral evolution in flash radiation by hypervelocity impact on aluminum plates 被引量:1
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作者 Xing Chen Yonggang Lu +1 位作者 Zhiwen Li Zhonghua Cui 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第7期96-110,共15页
In this study,a series of hypervelocity impact tests were carried out based on a two-stage light gas gun,and the sequence spectrum and radiation evolution data of the impact products under different impact conditions ... In this study,a series of hypervelocity impact tests were carried out based on a two-stage light gas gun,and the sequence spectrum and radiation evolution data of the impact products under different impact conditions were obtained.The diameter of the projectile is 3-5 mm,the impact velocity is 3.13-6.58 km/s,and the chamber pressure is 0.56-990 Pa.The spectrum of ejected debris cloud in the 250-310 nm band were obtained using a transient spectral measurement system and a multi-channel radiometer measurement system.The test results reveal that the flash radiation intensity increases as a power function with the kinetic energy of the impact.Furthermore,the peak value of the line spectrum decreases as the chamber vacuum degree increases,while the radiation width gradually expands.The line spectrum in the spectral characterization curve corresponds to the ejected debris clouds splitting phase,which does not produce significant line spectrum during material fragmentation and is dominated by the continuum spectrum produced by blackbody radiation.There will appear one or three characteristic peaks in the flash radiation time curve,the first and second peaks correspond to the penetration phase and the third peak corresponds to the expansion phase of the ejected debris clouds on the time scale,the first and second peaks are more sensitive to the chamber vacuum degree,and when the pressure is higher than 99 Pa,the first and second characteristic peaks will disappear.The radiant heat attenuation of the flash under different impact conditions is significantly different,the attenuation exponent has a power function relationship with the impact velocity and the chamber vacuum degree,while the attenuation exponent has a linear relationship with the diameter of the projectile,the specific expression of the attenuation exponent is obtained by fitting.The findings from this research can serve as a valuable reference for remote diagnostic technologies based on flash radiation characteristics. 展开更多
关键词 Hypervelocity impact Flash radiation EVOLUTION Spectral characteristics Damage evaluation
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Data processing method for aerial testing of rotating accelerometer gravity gradiometer 被引量:1
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作者 QIAN Xuewu TANG Hailiang 《中国惯性技术学报》 EI CSCD 北大核心 2024年第8期743-752,共10页
A novel method for noise removal from the rotating accelerometer gravity gradiometer(MAGG)is presented.It introduces a head-to-tail data expansion technique based on the zero-phase filtering principle.A scheme for det... A novel method for noise removal from the rotating accelerometer gravity gradiometer(MAGG)is presented.It introduces a head-to-tail data expansion technique based on the zero-phase filtering principle.A scheme for determining band-pass filter parameters based on signal-to-noise ratio gain,smoothness index,and cross-correlation coefficient is designed using the Chebyshev optimal consistent approximation theory.Additionally,a wavelet denoising evaluation function is constructed,with the dmey wavelet basis function identified as most effective for processing gravity gradient data.The results of hard-in-the-loop simulation and prototype experiments show that the proposed processing method has shown a 14%improvement in the measurement variance of gravity gradient signals,and the measurement accuracy has reached within 4E,compared to other commonly used methods,which verifies that the proposed method effectively removes noise from the gradient signals,improved gravity gradiometry accuracy,and has certain technical insights for high-precision airborne gravity gradiometry. 展开更多
关键词 airborne gravity gradiometer data processing band-passing filter evaluation function
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Evaluation Test Research of DR Inspection System for Circumferential Welds in Long Distance Pipeline
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作者 WANG Changjiang WANG Xue +4 位作者 ZHANG Shimin ZHAO Yan LYU Xinyu ZHONG Qian ZHOU Guangyan 《材料导报》 EI CAS CSCD 北大核心 2024年第22期223-229,共7页
Digital radiographic(DR)testing equipment has been widely promoted and applied in the inspection of circumferential welds in oil and gas pipelines.In order to establish a comprehensive quality control system for digit... Digital radiographic(DR)testing equipment has been widely promoted and applied in the inspection of circumferential welds in oil and gas pipelines.In order to establish a comprehensive quality control system for digital radiographic testing and fully evaluate the integrated system inspection ability of equipment,personnel,and processes,a scientific and standardized evaluation method to the system is very necessary.Here investigates the precedents of relevant non-destructive testing evaluation methods at home and abroad,considers the testing characteristics of DR equipment,develops a complete set of DR testing system evaluation procedures.It deeply studies the adaptability methods of program processes from defect production to slicing processing and data statistical calculation for digital radiographic testing evaluation.To check the repeatability and reliability of the detectable system,five process welds with 200 real metallographic defects were fabricated in the laboratory.From the detected results,the DR system has good repeatability in image quality,and the detectable defect size reaches 0.85 mm under achieving 90%detection probability at a confidence level of 95%,the error of detected defect length is±2 mm,and the error of detected defect localization is±5 mm.The qualitative and quantitative detection of defects are accurate and reliable.The test further confirmed the reliable detection ability of the DR detection system,and fully validated the scientific and practical evaluation method designed.The research on the evaluation test method can serve as an important link in the quality control system for the on-site application of digital ray equipment in long-distance pipelines.The designed program,test,and evaluation content can serve as an important basis for the formulation of relevant specifications or standards. 展开更多
关键词 digital ray evaluation test REPEATABILITY RELIABILITY
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Full-domain collaborative deployment method of multiple interference sources and evaluation of its deployment effect
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作者 Yue Wang Fuping Sun +2 位作者 Xian Wang Jinming Hao Kai Xiao 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期572-595,共24页
This paper realizes the full-domain collaborative deployment of multiple interference sources of the global satellite navigation system(GNSS)and evaluates the deployment effect to enhance the ability to disturb the at... This paper realizes the full-domain collaborative deployment of multiple interference sources of the global satellite navigation system(GNSS)and evaluates the deployment effect to enhance the ability to disturb the attacker and the capability to defend the GNSS during navigation countermeasures.Key evaluation indicators for the jamming effect of GNSS suppressive and deceptive jamming sources are first created,their evaluation models are built,and their detection procedures are sorted out,as the basis for determining the deployment principles.The principles for collaboratively deploying multi-jamming sources are developed to obtain the deployment structures(including the required number,structures in demand,and corresponding positions)of three single interference sources required by collaboratively deploying.Accordingly,simulation and hardware-in-loop testing results are presented to determine a rational configuration of the collaborative deployment of multi-jamming sources in the set situation and further realize the full-domain deployment of an interference network from ground,air to space.Varied evaluation indices for the deployment effect are finally developed to evaluate the deployment effect of the proposed configuration and further verify its reliability and rationality. 展开更多
关键词 Jamming effect Multiple interference sources Collaborative deployment Effect evaluation Defense capability
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An equivalent target plate damage probability calculation mathematics model and damage evaluation method
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作者 Hanshan Li Xiaoqian Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第11期82-103,共22页
Aiming at the requirement of damage testing and evaluation of equivalent target plate based on the explosion of intelligent ammunition, this paper proposes a novel method for damage testing and evaluation method of ci... Aiming at the requirement of damage testing and evaluation of equivalent target plate based on the explosion of intelligent ammunition, this paper proposes a novel method for damage testing and evaluation method of circumferential equivalent target plate. Leveraging the dispersion characteristics parameters of fragment, we establish a calculation model of the fragment power situation and the damage calculation model under the condition of fragment ultimate penetration equivalent target plate. The damage model of equivalent target plate involves the fragment dispersion density, the local perforation damage criterion, the tearing damage model, and the damage probability. We use the camera to obtain the image of the equivalent target plate with fragment perforation, and research the algorithm of fragment distribution position recognition and fragment perforation area calculation method on the equivalent target plate by image processing technology. Based on the obtained parameters of the breakdown position and perforation area of fragments on equivalent target plate, we apply to damage calculation model of equivalent target plate, and calculate the damage probability of each equivalent target plate, and use the combined probabilistic damage calculation method to obtain the damage evaluation results of the circumferential equivalent target plate in an intelligent ammunition explosion experiment. Through an experimental testing, we verify the feasibility and rationality of the proposed damage evaluation method by comparison, the calculation results can reflect the actual damage effect of the equivalent target plate. 展开更多
关键词 Target damage evaluation Damage probability FRAGMENTS Equivalent target plate Image processing
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Mission-oriented capability evaluation for combat network based on operation loops
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作者 Yang Wang Junyong Tao +2 位作者 Xiaoke Zhang Guanghan Bai Yunan Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第12期156-175,共20页
With continuous growth in scale,topology complexity,mission phases,and mission diversity,challenges have been placed for efficient capability evaluation of modern combat systems.Aiming at the problems of insufficient ... With continuous growth in scale,topology complexity,mission phases,and mission diversity,challenges have been placed for efficient capability evaluation of modern combat systems.Aiming at the problems of insufficient mission consideration and single evaluation dimension in the existing evaluation approaches,this study proposes a mission-oriented capability evaluation method for combat systems based on operation loop.Firstly,a combat network model is given that takes into account the capability properties of combat nodes.Then,based on the transition matrix between combat nodes,an efficient algorithm for operation loop identification is proposed based on the Breadth-First Search.Given the mission-capability satisfaction of nodes,the effectiveness evaluation indexes for operation loops and combat network are proposed,followed by node importance measure.Through a case study of the combat scenario involving space-based support against surface ships under different strategies,the effectiveness of the proposed method is verified.The results indicated that the ROI-priority attack method has a notable impact on reducing the overall efficiency of the network,whereas the O-L betweenness-priority attack is more effective in obstructing the successful execution of enemy attack missions. 展开更多
关键词 Combat network Operation loop identification Mission-oriented Network reliability Network effectiveness evaluation Strike strategies
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