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Impact of message fatigue and individual behavioral responses on epidemiological spread in temporal simplicial networks 被引量:1
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作者 Xiao-Nan Fan Xuemei You 《Chinese Physics B》 2025年第3期32-43,共12页
Health information spreads rapidly,which can effectively control epidemics.However,the swift dissemination of information also has potential negative impacts,which increasingly attracts attention.Message fatigue refer... Health information spreads rapidly,which can effectively control epidemics.However,the swift dissemination of information also has potential negative impacts,which increasingly attracts attention.Message fatigue refers to the psychological response characterized by feelings of boredom and anxiety that occur after receiving an excessive amount of similar information.This phenomenon can alter individual behaviors related to epidemic prevention.Additionally,recent studies indicate that pairwise interactions alone are insufficient to describe complex social transmission processes,and higher-order structures representing group interactions are crucial.To address this,we develop a novel epidemic model that investigates the interactions between information,behavioral responses,and epidemics.Our model incorporates the impact of message fatigue on the entire transmission system.The information layer is modeled using a static simplicial network to capture group interactions,while the disease layer uses a time-varying network based on activity-driven model with attractiveness to represent the self-protection behaviors of susceptible individuals and self-isolation behaviors of infected individuals.We theoretically describe the co-evolution equations using the microscopic Markov chain approach(MMCA)and get the epidemic threshold.Experimental results show that while the negative impact of message fatigue on epidemic transmission is limited,it significantly weakens the group interactions depicted by higher-order structures.Individual behavioral responses strongly inhibit the epidemic.Our simulations using the Monte Carlo(MC)method demonstrate that greater intensity in these responses leads to clustering of susceptible individuals in the disease layer.Finally,we apply the proposed model to real networks to verify its reliability.In summary,our research results enhance the understanding of the information-epidemic coupling dynamics,and we expect to provide valuable guidance for managing future emerging epidemics. 展开更多
关键词 Monte Carlo simulation microscopic Markov chain approach message fatigue information-epidemic coupled spreading simplicial complex
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Endoscopic and laparoscopic treatment of ileocecal laterally spreading tumor with concomitant appendiceal adenoma:A case report and review of literature
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作者 Ying-Hui Huang Li Ma +6 位作者 Bin Cao Yue-Juan Zhang Qun Gao Zhen-Ming Zhu Xiao-Lu Qiao Lei Wang Bao-Guo He 《World Journal of Gastrointestinal Surgery》 2025年第9期448-454,共7页
BACKGROUND Ileocecal laterally spreading tumors(LSTs)complicated by appendiceal tubular adenoma are rare and challenging to diagnose because of the absence of typical symptoms and specific diagnostic signs.Traditional... BACKGROUND Ileocecal laterally spreading tumors(LSTs)complicated by appendiceal tubular adenoma are rare and challenging to diagnose because of the absence of typical symptoms and specific diagnostic signs.Traditionally,the primary treatment has been laparoscopic appendectomy(LA).CASE SUMMARY A 63-year-old female presented with changes in bowel habits.Colonoscopy revealed an ileocecal LST.The patient underwent endoscopic submucosal dissection.Postoperative follow-up colonoscopy revealed mucosal elevation at the appendiceal orifice,with pathology confirming tubular adenoma.Abdominal computed tomography indicated a suspicious appendiceal tumor,leading to LA with partial cecectomy.The postoperative recovery was uneventful.At the 1-year follow-up,colonoscopy revealed no evidence of tumor recurrence.CONCLUSION Ileocecal LSTs with appendiceal tubular adenomas are traditionally treated with LA.endoscopic submucosal dissection can also yield favorable outcomes. 展开更多
关键词 Appendiceal tubular adenoma Ileocecal laterally spreading tumor Appendiceal laterally spreading tumor Endoscopic submucosal dissection Laparoscopic appendectomy Case report
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Modeling the spread risk of dengue vector Aedes albopictus caused by environmental factors in Shanghai China
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作者 Jiamin Wang Yanfeng Gong +7 位作者 Junhui Huang Ning Xu Yu Zhou Liyun Zhu Liang Shi Yue Chen Qingwu Jiang Yibiao Zhou 《Asian Pacific Journal of Tropical Medicine》 2025年第6期261-268,共8页
Objective:To predict the distribution of dengue vector Aedes(Ae.)albopictus and identify high-risk areas for dengue fever transmission.Methods:Data on Ae.albopictus occurrences were collected from electronic databases... Objective:To predict the distribution of dengue vector Aedes(Ae.)albopictus and identify high-risk areas for dengue fever transmission.Methods:Data on Ae.albopictus occurrences were collected from electronic databases.Ensemble models were developed to assess the impacts of climate,vegetation,and human activity on Ae.albopictus.The optimal ensemble model was then used to identify the distribution of suitable areas for Ae.albopictus.Results:After removing duplicate sites and retaining only one location per 100 m×100 m grid,189 Ae.albopictus breeding sites were identified.The optimal ensemble model revealed that Ae.albopictus exhibited higher breeding suitability in Shanghai under specific conditions:a normalized difference vegetation index of 0.1 to 0.6,maximum precipitation in the warmest month ranging from 400 mm to 470 mm,maximum temperature in the warmest month between 30.0℃and 31.0℃,and proximity to waterways within 0.5 km.The most suitable habitats for Ae.albopictus were primarily concentrated in Shanghai’s central urban areas and scattered across the inner suburban districts.Conclusions:The high-risk areas of Ae.albopictus are widely distributed throughout the central urban area and scattered across the inner suburban district of Shanghai,creating conditions conducive to the outbreak of dengue fever.It is essential to enhance targeted control measures for Ae.albopictus in the identified risk areas. 展开更多
关键词 DENGUE spread risk Prediction METROPOLITAN Aedes albopictus
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Influence of negative information dissemination and vaccination behavioral decision-making on epidemic spreading in a three-layer network
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作者 Liang'an Huo Leyao Yin 《Chinese Physics B》 2025年第6期667-681,共15页
Information plays a crucial role in guiding behavioral decisions during public health emergencies. Individuals communicate to acquire relevant knowledge about an epidemic, which influences their decisions to adopt pro... Information plays a crucial role in guiding behavioral decisions during public health emergencies. Individuals communicate to acquire relevant knowledge about an epidemic, which influences their decisions to adopt protective measures.However, whether to disseminate specific information is also a behavioral decision. In light of this understanding, we develop a coupled information–vaccination–epidemic model to depict these co-evolutionary dynamics in a three-layer network. Negative information dissemination and vaccination are treated as separate decision-making processes. We then examine the combined effects of herd and risk motives on information dissemination and vaccination decisions through the lens of game theory. The microscopic Markov chain approach(MMCA) is used to describe the dynamic process and to derive the epidemic threshold. Simulation results indicate that increasing the cost of negative information dissemination and providing timely clarification can effectively control the epidemic. Furthermore, a phenomenon of diminishing marginal utility is observed as the cost of dissemination increases, suggesting that authorities do not need to overinvest in suppressing negative information. Conversely, reducing the cost of vaccination and increasing vaccine efficacy emerge as more effective strategies for outbreak control. In addition, we find that the scale of the epidemic is greater when the herd motive dominates behavioral decision-making. In conclusion, this study provides a new perspective for understanding the complexity of epidemic spreading by starting with the construction of different behavioral decisions. 展开更多
关键词 negative information VACCINATION epidemic spreading behavioral decision-making three-layer network
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SPREADING SPEED FOR A TIME-SPACE PERIODIC EPIDEMIC MODEL IN DISCRETE MEDIA
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作者 Haiqin ZHAO 《Acta Mathematica Scientia》 2025年第3期1005-1018,共14页
This paper is devoted to investigating the spreading speed of a time-space periodic epidemic model with vital dynamics and standard incidence in discrete media. We establish the existence of the leftward and rightward... This paper is devoted to investigating the spreading speed of a time-space periodic epidemic model with vital dynamics and standard incidence in discrete media. We establish the existence of the leftward and rightward spreading speeds for the infective individuals, which can be used to estimate how fast the disease spreads. To overcome the difficulty arising from the lack of comparison principle for such time-space periodic nonmonotone systems, our proof is mainly based on constructing a series of scalar time-space periodic equations, establishing the spreading speeds for such auxiliary equations and using comparison methods. It may be the first work to study the spreading speed for time-space periodic non-monotone systems. 展开更多
关键词 spreading speed epidemic models time-space periodic habitats
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A stacking-based model for the spread of Botryosphaeria laricina
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作者 Hongwei Zhou Shibo Zhang +3 位作者 Meng Xie Xiaodong Li Yifan Chen Wenhao Dai 《Journal of Forestry Research》 2025年第1期427-443,共17页
Botryosphaeria laricina(larch shoot blight)was first identified in 1973 in Jilin Province,China.The disease spread rapidly and caused considerable damage because its pathogenesis was unknown at the time and there were... Botryosphaeria laricina(larch shoot blight)was first identified in 1973 in Jilin Province,China.The disease spread rapidly and caused considerable damage because its pathogenesis was unknown at the time and there were no effective controls or quarantine methods.At present,it shows a spreading trend,but most research can only conduct physiological analyses within a relatively short period,combining individual influencing factors.Nevertheless,methods such as neural network models,ensemble learning algorithms,and Markov models are used in pest and disease prediction and forecasting.However,there may be fitting issues or inherent limitations associated with these methods.This study obtained B.laricina data at the county level from 2003 to 2021.The dataset was augmented using the SMOTE algorithm,and then algorithms such as XGBoost were used to select the significant features from a combined set of 12 features.A new stacking fusion model has been proposed to predict the status of B.laricina.The model is based on random forest,gradient boosted decision tree,CatBoost and logistic regression algorithms.The accuracy,recall,specificity,precision,F_(1) value and AUC of the model reached 90.9%,91.6%,90.4%,88.8%,90.2%and 96.2%.The results provide evidence of the strong performance and stability of the model.B.laricina is mainly found in the northeast and this study indicates that it is spreading northwest.Reasonable means should be used promptly to prevent further damage and spread. 展开更多
关键词 Botryosphaeria laricina Data augmentation Feature selection STACKING Status of spread
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Explosive information spreading in higher-order networks:Effect of social reinforcement
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作者 Yu Zhou Yingpeng Liu +4 位作者 Liang Yuan Youhao Zhuo Kesheng Xu Jiao Wu Muhua Zheng 《Chinese Physics B》 2025年第3期196-202,共7页
Information spreading has been investigated for many years,but the mechanism of why the information explosively catches on overnight is still under debate.This explosive spreading phenomenon was usually considered dri... Information spreading has been investigated for many years,but the mechanism of why the information explosively catches on overnight is still under debate.This explosive spreading phenomenon was usually considered driven separately by social reinforcement or higher-order interactions.However,due to the limitations of empirical data and theoretical analysis,how the higher-order network structure affects the explosive information spreading under the role of social reinforcement has not been fully explored.In this work,we propose an information-spreading model by considering the social reinforcement in real and synthetic higher-order networks,describable as hypergraphs.Depending on the average group size(hyperedge cardinality)and node membership(hyperdegree),we observe two different spreading behaviors:(i)The spreading progress is not sensitive to social reinforcement,resulting in the information localized in a small part of nodes;(ii)a strong social reinforcement will promote the large-scale spread of information and induce an explosive transition.Moreover,a large average group size and membership would be beneficial to the appearance of the explosive transition.Further,we display that the heterogeneity of the node membership and group size distributions benefit the information spreading.Finally,we extend the group-based approximate master equations to verify the simulation results.Our findings may help us to comprehend the rapidly information-spreading phenomenon in modern society. 展开更多
关键词 explosive information spreading social reinforcement higher-order interactions complex network
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Trending and emerging prospects of physics-based and ML-based wildfire spread models:a comprehensive review
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作者 Harikesh Singh Li‑Minn Ang +4 位作者 Tom Lewis Dipak Paudyal Mauricio Acuna Prashant Kumar Srivastava Sanjeev Kumar Srivastava 《Journal of Forestry Research》 2025年第1期27-59,共33页
The significant threat of wildfires to forest ecology and biodiversity,particularly in tropical and subtropical regions,underscores the necessity for advanced predictive models amidst shifting climate patterns.There i... The significant threat of wildfires to forest ecology and biodiversity,particularly in tropical and subtropical regions,underscores the necessity for advanced predictive models amidst shifting climate patterns.There is a need to evaluate and enhance wildfire prediction methods,focusing on their application during extended periods of intense heat and drought.This study reviews various wildfire modelling approaches,including traditional physical,semi-empirical,numerical,and emerging machine learning(ML)-based models.We critically assess these models’capabilities in predicting fire susceptibility and post-ignition spread,highlighting their strengths and limitations.Our findings indicate that while traditional models provide foundational insights,they often fall short in dynamically estimating parameters and predicting ignition events.Cellular automata models,despite their potential,face challenges in data integration and computational demands.Conversely,ML models demonstrate superior efficiency and accuracy by leveraging diverse datasets,though they encounter interpretability issues.This review recommends hybrid modelling approaches that integrate multiple methods to harness their combined strengths.By incorporating data assimilation techniques with dynamic forecasting models,the predictive capabilities of ML-based predictions can be significantly enhanced.This review underscores the necessity for continued refinement of these models to ensure their reliability in real-world applications,ultimately contributing to more effective wildfire mitigation and management strategies.Future research should focus on improving hybrid models and exploring new data integration methods to advance predictive capabilities. 展开更多
关键词 Wildfire spread Fire prediction models Cellular automata model WRF-Fire/SFire FIRETEC CAWFE WFDS
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Activation of peroxymonosulfate by sustainable biomass-based carbon nanotubes for controlling the spread of plant viruses in water environments
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作者 Jian Tang Yujie Wang +2 位作者 JunMa Yujie Chen Ming Chen 《Journal of Environmental Sciences》 2025年第3期99-112,共14页
With the increasing demand for water in hydroponic systems and agricultural irrigation,viral diseases have seriously affected the yield and quality of crops.By removing plant viruses in water environments,virus transm... With the increasing demand for water in hydroponic systems and agricultural irrigation,viral diseases have seriously affected the yield and quality of crops.By removing plant viruses in water environments,virus transmission can be prevented and agricultural production and ecosystems can be protected.But so far,there have been few reports on the removal of plant viruses in water environments.Herein,in this study,easily recyclable biomass-based carbon nanotubes catalysts were synthesized with varying metal activities to activate peroxymonosulfate(PMS).Among them,the magnetic 0.125Fe@NCNTs-1/PMS system showed the best overall removal performance against pepper mild mottle virus,with a 5.9 log_(10)removal within 1 min.Notably,the key reactive species in the 0.125Fe@NCNTs-1/PMS system is^(1)O_(2),which can maintain good removal effect in real water matrices(river water and tap water).Through RNA fragment analyses and label free analysis,it was found that this system could effectively cleave virus particles,destroy viral proteins and expose their genome.The capsid protein of pepper mild mottle virus was effectively decomposed where serine may be the main attacking sites by^(1)O_(2).Long viral RNA fragments(3349 and 1642 nt)were cut into smaller fragments(∼160 nt)and caused their degradation.In summary,this study contributes to controlling the spread of plant viruses in real water environment,which will potentially help protect agricultural production and food safety,and improve the health and sustainability of ecosystems. 展开更多
关键词 Pepper mild mottle virus Removal Plant virus spread Biomass-based carbon nanotubes Water environments
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Endoscopic resection of colorectal laterally spreading tumors:Clinicopathologic characteristics and risk factors for treatment outcomes
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作者 Li-Hua Guo Ke-Feng Hu +3 位作者 Min Miao Yong Ding Xin-Jun Zhang Guo-Liang Ye 《World Journal of Gastrointestinal Endoscopy》 2025年第6期85-98,共14页
BACKGROUND Colorectal laterally spreading tumors(LSTs)are best treated with endoscopic submucosal dissection or endoscopic mucosal resection.AIM To analyze the clinicopathological and endoscopic profiles of colorectal... BACKGROUND Colorectal laterally spreading tumors(LSTs)are best treated with endoscopic submucosal dissection or endoscopic mucosal resection.AIM To analyze the clinicopathological and endoscopic profiles of colorectal LSTs,determine predictive factors for high-grade dysplasia(HGD)/carcinoma(CA),submucosal invasion,and complications.METHODS We retrospectively assessed the endoscopic and histological characteristics of 375 colorectal LSTs at our hospital between January 2016 and December 2023.We performed univariate and multivariate analysis to identify risk factors associated with HGD/CA,submucosal invasion and complications.RESULTS The numbers of granular(LST-G)and non-granular LST(LST-NG)were 260 and 115,respectively.The rates of low-grade dysplasia and HGD/CA were 60.3%and 39.7%,respectively.Multivariate analysis indicated that a tumor size≥30 mm[odds ratio(OR)=1.934,P=0.032],LST granular nodular mixed type(OR=2.100,P=0.005),and LST non-granular pseudo depressed type(NG-PD)(OR=3.016,P=0.015)were independent risk factors significantly associated with higher odds of HGD/CA.NG-PD(OR=6.506,P=0.001),tumor size(20-29 mm)(OR=2.631,P=0.036)and tumor size≥30 mm(OR=3.449,P=0.016)were associated with increased odds of submucosal invasion.Tumor size≥30 mm(OR=4.888,P=0.003)was a particularly important predictor of complications.A nomogram model demonstrated a satisfactory fit,with an area under the receiver operating characteristic curve of 0.716(95%confidence interval:0.653-0.780),indicating strong predictive performance.CONCLUSION The novel nomogram incorporating tumor size,location,and morphology predicted HGD/CA during endoscopic resection for LSTs.NG-PD lesions larger than 20 mm were more likely to invade the submucosa.Tumor size≥30 mm was an important predictor of complications. 展开更多
关键词 Colorectal neoplasms Laterally spreading tumor Endoscopic morphology Endoscopic submucosal dissection Endoscopic mucosal resection Submucosal invasion
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基于元胞自动机模型的松材线虫病小班尺度预测
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作者 周宏威 李永正 +5 位作者 郭文辉 陈怡帆 胡浩昌 张思岩 崔迪 陈雨茉 《林业科学》 北大核心 2026年第1期133-143,共11页
【目的】为探究影响松材线虫病传播扩散的主要影响因素,结合自然气候、人类活动以及地理空间特征多源数据,围绕松材线虫病“传入-定殖-扩散”的生态入侵过程,构建适用于更小空间尺度数据的传播预测模型,实现对松材线虫病高风险发生地区... 【目的】为探究影响松材线虫病传播扩散的主要影响因素,结合自然气候、人类活动以及地理空间特征多源数据,围绕松材线虫病“传入-定殖-扩散”的生态入侵过程,构建适用于更小空间尺度数据的传播预测模型,实现对松材线虫病高风险发生地区的精准预测和早期预警。【方法】基于国家林业和草原局公布的江苏省松材线虫病小班本底发生数据,结合松材线虫病的生态特性和地理空间分布规律,选取包含自然气候、人类活动因素以及空间特征等25项影响因子数据,采用主成分分析方法进行数据预处理,通过Spearman相关性分析方法和Apriori数据挖掘算法,探究各影响因子与松材线虫病发生之间的相互作用关系。结合贝叶斯估计方法对影响因子数据进行特征增强,建立灰狼优化算法-元胞自动机模型模拟松材线虫病的传播扩散过程,同时与其他5种主流机器学习模型预测结果进行横向对比验证,通过计算其精确率、召回率和AUC等评价指标对模型性能进行验证。【结果】构建的灰狼优化算法-元胞自动机模型在松材线虫病新发小班预测中表现出优异的性能,模型召回率达到78.5%,显著优于其他5种主流机器学习模型;同时,其AUC值达到89.0%,表明模型在识别新发疫情点位的同时,兼顾较高的整体预测准确性与判别能力。本研究进一步证实地理空间特征在松材线虫病传播预测中的重要性,并验证元胞自动机模型在处理复杂时空数据和更精细尺度空间数据预测方面的高度适用性。【结论】木材运输是驱动松材线虫病传播扩散的关键因素,而温度与降水的差异也在显著程度上影响其发生风险。作为一种融合空间异质性与时间动态特征的建模方法,元胞自动机模型在处理复杂生态数据与入侵物种风险评估方面展现出较高的适用性与灵活性,可为松材线虫病的精准防控与高效管理提供有力的技术支撑。 展开更多
关键词 松材线虫病 传播预测模型 大数据 数据挖掘 元胞自动机
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面肌痉挛患者显微血管减压术中侧方扩散反应与术后近远期疗效的关系
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作者 王凯 尚明 《中国实用神经疾病杂志》 2026年第1期14-19,共6页
目的探究面肌痉挛患者显微血管减压术(MVD)中侧方扩散反应(LSR)与术后近远期疗效的关系。方法回顾性分析2020-02—2024-02徐州市中心医院收治的110例面肌痉挛患者的临床资料,将颧支和下颌缘支LSR均消失或两支中任一支消失纳入LSR消失组(... 目的探究面肌痉挛患者显微血管减压术(MVD)中侧方扩散反应(LSR)与术后近远期疗效的关系。方法回顾性分析2020-02—2024-02徐州市中心医院收治的110例面肌痉挛患者的临床资料,将颧支和下颌缘支LSR均消失或两支中任一支消失纳入LSR消失组(n=97),颧支和下颌缘支LSR均未消失纳入LSR未消失组(n=13)。分析LSR消失组颧支与下颌缘支LSR消失情况,分析LSR是否消失、消失时机与术后近期(1周内)、远期(1周~1 a)疗效的关系,绘制受试者工作特征(ROC)曲线评价LSR是否消失、消失时机对术后面肌痉挛近期、远期疗效的预测效能。结果术后近期、远期疗效比较,LSR消失组优于LSR未消失组,差异均有统计学意义(P<0.05)。不同术中LSR消失时机患者术后面肌痉挛近期、远期疗效比较有统计学差异(P<0.05)。ROC曲线分析显示,LSR是否消失评估术后面肌痉挛近期、远期疗效的AUC分别为0.621、0.702,敏感度分别为90.82%、90.38%,特异度分别为33.33%、50.00%;LSR消失时机评估术后面肌痉挛近期、远期疗效的AUC分别为0.631、0.691,敏感度分别为63.73%、63.21%,特异度分别为62.50%、75.00%。结论面肌痉挛患者术中LSR是否消失及消失时机对MVD术后近远期疗效具有一定的预测价值,临床应结合患者的临床症状及其他辅助检查综合判断,以改善患者长期预后。 展开更多
关键词 面肌痉挛 显微血管减压术 侧方扩散反应 预后 预测效能
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权力寻租:粤海关陋规名目及其危害
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作者 王宏斌 《河北师范大学学报(哲学社会科学版)》 2026年第1期21-38,共18页
“陋规”,乃是明清时期一种缺乏明确规定的,却又是实际运行的,得到官场默认的、普遍存在的、收受费用之潜规则。粤海关作为清代对外贸易的窗口,是一个比较特殊的部门。粤海关陋规名目前后有25种之多,几乎遍及收税、查验的每一个环节。... “陋规”,乃是明清时期一种缺乏明确规定的,却又是实际运行的,得到官场默认的、普遍存在的、收受费用之潜规则。粤海关作为清代对外贸易的窗口,是一个比较特殊的部门。粤海关陋规名目前后有25种之多,几乎遍及收税、查验的每一个环节。追根溯源,陋规的孽生和传染,既是官吏薪水制度、政府财政制度存在较大漏洞导致的,更是人治社会和缺乏内外监督造成的。粤海关陋规既具有一定遗传性,又具有巨大社会危害性和传染性。1840年之前的中国毒品泛滥,既是英属印度政府千方百计扶持对华鸦片走私贸易的结果,又与粤海关陋规盛行存在一定的因果联系。 展开更多
关键词 粤海关 陋规名目 权力寻租 传染性 鸦片战争
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双圈图的Laplace spread 被引量:1
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作者 李平 施劲松 李瑞林 《华东师范大学学报(自然科学版)》 CAS CSCD 北大核心 2010年第1期6-9,共4页
图的Laplace spread定义为图的最大Laplace特征值与次小Laplace特征值之差.利用多项式函数的性质,得到了具有最大Laplace spread的双圈图.
关键词 LAPLACE特征值 双圈图 LAPLACE spread
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双圈图的Laplacian Spread(英文) 被引量:1
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作者 刘颖 王立庆 《数学进展》 CSCD 北大核心 2011年第6期759-764,共6页
Laplacian spread的概念在刻画图的整体性质方面非常重要.近年来,Fan等分别刻画了树中具有极大和极小Laplacian spread的图.另外Bao等确定了在所有单圈图中具有极大Laplacian spread的图.边数减去顶点数目为1的连通图称为双圈图.令B_n... Laplacian spread的概念在刻画图的整体性质方面非常重要.近年来,Fan等分别刻画了树中具有极大和极小Laplacian spread的图.另外Bao等确定了在所有单圈图中具有极大Laplacian spread的图.边数减去顶点数目为1的连通图称为双圈图.令B_n是所有有n个顶点构成的双圈图集合.对n≥11,本文确定了B_n中所有具有极大Laplacian spread的那些图. 展开更多
关键词 双圈图 LAPLACIAN spread LAPLACIAN特征值
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中性风在中低纬Spread-F中的作用 被引量:4
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作者 谢红 刘滨莎 萧佐 《北京大学学报(自然科学版)》 CAS CSCD 北大核心 1996年第1期78-88,共11页
讨论了中低纬度电离层F区中有碰撞的Rayleigh-Taylor不稳定性的线性增长率,着重考察背景中性风对增长率的影响,首先建立了适合于描述中低纬地区R-T不稳定性的基本方程,其中包括背景中性风和电场。在此基础上导出了色散关系和不稳定性增... 讨论了中低纬度电离层F区中有碰撞的Rayleigh-Taylor不稳定性的线性增长率,着重考察背景中性风对增长率的影响,首先建立了适合于描述中低纬地区R-T不稳定性的基本方程,其中包括背景中性风和电场。在此基础上导出了色散关系和不稳定性增长率γ。结果表明,γ随纬度增加而逐渐减小,虽然东西方向和垂直向下的中性风分量有利于不稳定性增长,但在比30度更高的纬度,正常的背景中性风很难使γ为正值,除非存在合适的东西方向电场,亦即电场在中纬度Spread F的形成方面起着重要的作用。文中还根据比较合乎实际的电离层电子密度分布模式估算了线性增长率γ的季节变化。 展开更多
关键词 中纬扩展F 中性风 电离层 R-T不稳定性 spread-F
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声重波激发的赤道Spread—F的拓扑特性研究 被引量:1
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作者 谢红 萧佐 王宪民 《空间科学学报》 CAS CSCD 北大核心 1997年第4期309-316,共8页
本文对声重波激发的Spread-F扰动的非线性制约方程的拓扑特性进行了定性讨论和数值计算.研究了Spread-F的混沌特征及参数范围.结果表明声重波在不同条件时对Spread-F的激发作用有本质的不同.
关键词 spread-F 声重波 混沌 拓扑 赤道 电离层
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基于Spread业务支撑系统的拓扑构造
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作者 董立岩 殷涵 +2 位作者 王利民 毛锐 黄乐 《吉林大学学报(理学版)》 CAS CSCD 北大核心 2011年第6期1073-1078,共6页
基于Spread具有的高度灵活性和自动发现功能,构造一个基于Spread的业务支撑系统,并研究了该系统的拓扑构造,给出了系统拓扑常见的4种情况:服务节点加入、服务节点离开、动态拓扑增加和动态拓扑减少的算法.仿真实验表明,该系统具有良好... 基于Spread具有的高度灵活性和自动发现功能,构造一个基于Spread的业务支撑系统,并研究了该系统的拓扑构造,给出了系统拓扑常见的4种情况:服务节点加入、服务节点离开、动态拓扑增加和动态拓扑减少的算法.仿真实验表明,该系统具有良好的稳定性、扩展性和容灾抗毁能力. 展开更多
关键词 拓扑构造 spread中间件 算法 业务支撑系统
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一种类Spreadsheet结构的信息汇聚方法
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作者 魏永山 韩燕波 +2 位作者 孙忠林 张峰 陈欣 《计算机科学》 CSCD 北大核心 2010年第5期134-138,共5页
SpreadSheet样式的数据操作具有很好的可用性,但在SpreadSheet结构中如何表示并操纵XML数据以及如何使用复制、粘贴、移动等简单操作表示复杂的XQuery查询是两个难点问题。提出一种基于XML模式的操作表示方法,将复杂的XQuery查询语句分... SpreadSheet样式的数据操作具有很好的可用性,但在SpreadSheet结构中如何表示并操纵XML数据以及如何使用复制、粘贴、移动等简单操作表示复杂的XQuery查询是两个难点问题。提出一种基于XML模式的操作表示方法,将复杂的XQuery查询语句分解为XML模式上的粘贴节点、移动节点等操作,从而可以表示XQuery语言的核心语句FLOWR。在Spreadsheet结构中将XML模式显示为嵌套表格,用户在嵌套表格上的操作转换为XML模式上的操作。使用该方法可以构造多数据源的XQuery查询,并实现了概念验证的原型系统。与当前流行的XQuery查询构造工具相比较,原型系统更适合于无编程经验的最终用户构造XQuery查询。 展开更多
关键词 spread SHEET XQUERY 信息集成 信息资源汇聚
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