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Analysis of a Rare Large-scale Hail Process in Yantai and Weihai
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作者 Liping ZHANG Chanjuan MEI Fan LIAN 《Meteorological and Environmental Research》 CAS 2023年第4期5-11,共7页
A rare large-scale hail process in Yantai and Weihai City in the autumn of 2021 was analyzed based on the surface meteorology,high-altitude observation and S-band radar detection data.The results showed that this proc... A rare large-scale hail process in Yantai and Weihai City in the autumn of 2021 was analyzed based on the surface meteorology,high-altitude observation and S-band radar detection data.The results showed that this process was influenced by shallow trough,and strong upper-level jet stream in the middle and upper levels guided the intrusion of mid-level cold air into the warm and humid environment at the lower level.The shear lines and trunk lines in the lower level also provided certain triggering conditions for uplift,brewing conditions suitable for the occurrence and development of strong convection.The vertical wind shear was unusually large,and vertical wind shear was up to 10 m/s at 0-1 km,20 m/s at 0-3 km,and 32 m/s at 0-6 km,which was conducive to the growth of the storm.In this process,isolated multi-cell thunderstorm was generated at the beginning,and then it developed and strengthened continuously,moving to the southeast.In the later stage,a convection cell was born at the boundary between Yantai and Weihai,and developed into supercell storm.The storm lasted for a long time,and continued to develop and strengthen as it moved eastward,affecting most areas of Weihai from northwest to southeast.In the development stage of the storm,the radar reflectivity factor had obvious characteristics of hook echo and three-body scatter spike,and there was echo overhang and other hail echo features in the middle layer.Weak mesocyclone appeared at a low elevation,and there was the potential for the occurrence of tornado. 展开更多
关键词 HAIL STORM AUTUMN Yantai Weihai
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Changing Characteristics of Urban Heat Island Effect in Weihai City
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作者 Di WANG Qianqian SUN Wenpeng XIN 《Meteorological and Environmental Research》 2023年第6期8-15,共8页
Based on the local climate zoning theory and the observation data of hourly temperature of 22 automatic weather stations from 2012 to 2021, K-means clustering algorithm was used to analyze the daily, monthly, seasonal... Based on the local climate zoning theory and the observation data of hourly temperature of 22 automatic weather stations from 2012 to 2021, K-means clustering algorithm was used to analyze the daily, monthly, seasonal, annual and spatial variation characteristics of urban heat island effect in Weihai City in the past 10 years. The results showed that in recent 10 years, the average urban heat island intensity was 1.24 ℃, showing a gradual weakening trend of -0.169 3 ℃/10 a;the summer average heat island intensity was 0.86 ℃, showing a gradual weakening trend of -0.047 5 ℃/10 a. The heat island intensity had obvious diurnal variation characteristics, that is, "it was weak in the day and strong at night". In terms of seasonal variation, heat island effect was the weakest in summer, stronger in spring and autumn, and the strongest in winter. The diurnal, seasonal and annual changes of heat island intensity showed a reverse trend to those of temperature. The high-value area of urban heat island was highly consistent with human residential activity areas and industrial and commercial intensive areas, and the extension trend of heat island intensity was the same as the direction of urban development and construction. The "cold island phenomenon" in some offshore areas was related to the geographical location, terrain and the southeast monsoon trend in summer. The adverse effects of urban heat island effect can be reduced by optimizing the types and distribution of vegetation communities, rationally planning and constructing urban water body, promoting green building materials and adjusting shape design, etc. 展开更多
关键词 Urban heat island effect Local climate zoning K-means clustering algorithm Automatic weather station
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Taxonomic and genetic status of lancelet in Weihai coastal waters based on mitochondrial DNA sequence
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作者 赵琦 祝茜 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2011年第3期623-632,共10页
Lancelets (subphylum Cephalochordata) are a transitional species between invertebrates and vertebrates. They are currently listed in the Second Order of Protected Animals in China. Lancelets were first documented in t... Lancelets (subphylum Cephalochordata) are a transitional species between invertebrates and vertebrates. They are currently listed in the Second Order of Protected Animals in China. Lancelets were first documented in the waters around the city of Weihai (Shandong, China) in 2002. However, little is known about the phylogeny of this population. We analyzed the sequences of cytochrome b (Cyt b) and cytochrome oxidase c subunit I (CO I) genes from samples collected from coastal waters in the cities of Weihai and Qingdao (~150 km to the south). We analyzed 176 sequences, of which 150 were novel sequences and 26 were obtained from GenBank. Our results suggest that (1) lancelets in the two cities belong to the species Branchiostoma japonicus and have a high level of genetic diversity; (2) there is a high level of gene flow and low level of genetic differentiation between lancelets from the two cities; (3) demographic expansion occurred an estimated 1.1 million years (Ma) ago (mid Pleistocene) for lancelets in Weihai-Qingdao; and (4) the divergence between B. belcheri and B. japonicus was estimated at between 37.75 Ma (early Oligocene)-46.5 Ma (late Eocene). 展开更多
关键词 DNA序列 遗传多样性 沿海水域 威海市 线粒体 文昌鱼 细胞色素氧化酶 GENBANK
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Key Points for High-yield Cultivation Management of Pseudostellaria heterophylla in Weihai Area
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作者 Lijuan HOU Jiawei WANG +2 位作者 Jing HU Jilei MAO Xiaowei TIAN 《Medicinal Plant》 CAS 2019年第1期54-56,共3页
[Objectives] To explore the scientific cultivation mode of Pseudostellaria heterophylla in Shandong Province. [Methods] According to the ecological characteristics of P. heterophylla, the cultivation techniques and ma... [Objectives] To explore the scientific cultivation mode of Pseudostellaria heterophylla in Shandong Province. [Methods] According to the ecological characteristics of P. heterophylla, the cultivation techniques and management points of P. heterophylla in Weihai are summarized. [Results] The scientific cultivation techniques and management points of P. heterophylla are introduced from the aspects of land selection, land preparation, seed selection, seedling nursing, timely sowing and transplanting, field management and disease and pest control. [Conclusions] This study will provide theoretical guidance for the high-quality, high-yield and high-efficiency cultivation of P. heterophylla in Shandong area. 展开更多
关键词 Pseudostellaria heterophylla SCIENTIFIC CULTIVATION MANAGEMENT HIGH YIELD
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Tectonic activity and earthquake risk in the Chengnanhe fault zone in Weihai city,Shandong province,China,obtained by using an integrated prospecting technique in geophysics and geology
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作者 Gui-Lin Du Lian-Feng Zhao +6 位作者 Xiaobo Tian Shujuan Su Xiangchun Chang Hualin Wang Zhuqing Huo Tao Zhu Yonghua Li 《Earthquake Science》 2021年第2期137-147,共11页
For city planning and reducing potential earthquake risk,it’s necessary to detect the information of the buried faults in an urban area especially,including the location and activities.An integrated technique with ge... For city planning and reducing potential earthquake risk,it’s necessary to detect the information of the buried faults in an urban area especially,including the location and activities.An integrated technique with geophysical and geological methods,including the shallow seismic reflection profile,electrical resistivity measurement,geologic borehole section,and exploration trench,was used to detect the Chengnanhe fault,which is one of the two main faults passing through the Weihai urban area in Shandong province,China.The results show that it is a normal fault striking with E-W direction,and it is relatively inactive and stable.By using the thermoluminescence(TL)dating,we found that the Chengnanhe fault initiated in mid-Pleistocene and there was no offset after late Pleistocene.Such an integrated technique with multiple geological and geophysical methods provides a significant assessment of earthquake risk for city planning in urban areas. 展开更多
关键词 Chengnanhe fault geologic drilling thermoluminescence(TL)dating shallow seismic profile electrical resistivity measurement.
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Research on the Dilemma and Countermeasures of Graduate Student Recruitment Publicity in University Branch Area-Based on Harbin Institute of Technology(Weihai)
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作者 Lianmao Yang Yiqun Liu Zaixian Chen 《教育研究前沿(中英文版)》 2022年第3期90-95,共6页
Graduate student recruitment publicity is a very important link in graduate student recruitment,the quality of students directly affects the quality of graduate education.Taking Harbin Institute of Technology(Weihai)a... Graduate student recruitment publicity is a very important link in graduate student recruitment,the quality of students directly affects the quality of graduate education.Taking Harbin Institute of Technology(Weihai)as the research object,this paper analyzes the internal and external factors affecting the improvement of graduate student quality in the branch campus,and carries out the corresponding countermeasures,puts forward the propaganda strategy of all-round research and recruitment,and effectively improves the quality of graduate student in the branch campus. 展开更多
关键词 Graduate Student Recruitment Publicity Countermeasure Research University Branch Area
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Analysis and Suggestions of the Satisfaction of Postgraduate Education in Engineering Universities —Take Harbin Institute of Technology (Weihai) for Example
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作者 Lianmao Yang Yiqun Liu +1 位作者 Xiaoguo Song Bingfeng Liu 《教育研究前沿(中英文版)》 2022年第2期56-62,共7页
Accelerating the development of students is the basic goal of postgraduate talent cultivation.The final research results,employment situation and satisfaction of postgraduate students with school education are more im... Accelerating the development of students is the basic goal of postgraduate talent cultivation.The final research results,employment situation and satisfaction of postgraduate students with school education are more important indicators of the quality of talent cultivation in a university.For having a deeper understanding of the satisfaction of postgraduates in Harbin Institute of Technology(Weihai)in terms of motivation,tutor situation,management service and employment situation,a questionnaire survey was conducted on postgraduates.The survey results show that the overall satisfaction of postgraduates is high.In terms of studying motivation,most postgraduates think that their majors are more related to employment;in terms of professors,most of them can get along well with their professors and learn from the advantages of their professors;in terms of school management,they respond well to the"library",but think that the"dormitory"and"canteen"need further improvement;in terms of employment,most of postgraduates choose to be employed,while a few of them choose to further their studies,most of which have applied to study in domestic or foreign universities. 展开更多
关键词 Engineering Universities Postgraduate Education SATISFACTION Survey Analysis
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Molecular Epidemiological Study of a Human Brucellosis Outbreak—Weihai City,Shandong Province,China,2022
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作者 Yan Li Yifan Yu +4 位作者 Jian Zhao Shujun Ding Guoying Zhang Xiaolin Yu Zengqiang Kou 《China CDC weekly》 SCIE CSCD 2024年第12期230-234,共5页
What is already known about this topic?Brucellosis,mainly caused by Brucella melitensis(B.melitensis),is regarded as a significant zoonotic disease in China.In Weihai,located at the eastern end of the Shandong Peninsu... What is already known about this topic?Brucellosis,mainly caused by Brucella melitensis(B.melitensis),is regarded as a significant zoonotic disease in China.In Weihai,located at the eastern end of the Shandong Peninsula,brucellosis has been in a low epidemic phase for the past five years.What is added by this report?This was the initial report of a brucellosis outbreak in the last five years.Strains of B.melitensis bv.3 from Weihai and other cities showed a close genetic relationship,suggesting a potential common ancestry.What are the implications for public health practice?Epidemiological investigations depend on standardized and effective molecular typing methods and analysis tools for public health laboratories to identify and trace outbreaks.Understanding the circulation patterns of livestock in free-range households in heavily affected areas is essential for controlling the spread of brucellosis. 展开更多
关键词 SHANDONG China. BREAK
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基于LDA主题模型的中国图书出口效果研究——以亚马逊海外读者评论为例 被引量:1
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作者 杜恒波 王绍运 罗润东 《经济问题》 北大核心 2024年第2期17-23,共7页
中华文化通过图书走向世界舞台,是提高国家文化软实力、讲好中国故事、塑造良好国家形象的有效途径。通过Python语言工具对美国亚马逊网站上的中国图书评论数据进行分析,构建LDA主题模型,探讨中国图书出口效果,深入挖掘海外读者对中国... 中华文化通过图书走向世界舞台,是提高国家文化软实力、讲好中国故事、塑造良好国家形象的有效途径。通过Python语言工具对美国亚马逊网站上的中国图书评论数据进行分析,构建LDA主题模型,探讨中国图书出口效果,深入挖掘海外读者对中国出口图书的认知评价。研究发现,海外读者对中国图书的关注点集中于内容评价、翻译理解、服务体验、中国元素、题材情节5个方面。针对以上关注点,从图书内容、出版传播、读者反馈等角度提出了具有实践价值的建议,为推动中国图书高质量出口提供了理论参考和解决思路。 展开更多
关键词 中国图书 出口效果 亚马逊读者评论
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基于计算机辅助半自动测量的颅内动脉瘤形态学参数与动脉瘤破裂相关性分析
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作者 王雅栋 耿介文 +2 位作者 胡鹏 何川 张鸿祺 《中国脑血管病杂志》 CAS CSCD 北大核心 2024年第5期289-296,共8页
目的评估计算机辅助半自动测量的动脉瘤三维形态学参数与动脉瘤破裂风险的相关性。方法回顾性连续纳入2019年10月至2022年10月于首都医科大学宣武医院神经外科收治的破裂多发动脉瘤患者。采用计算机辅助半自动测量方法测量入组患者动脉... 目的评估计算机辅助半自动测量的动脉瘤三维形态学参数与动脉瘤破裂风险的相关性。方法回顾性连续纳入2019年10月至2022年10月于首都医科大学宣武医院神经外科收治的破裂多发动脉瘤患者。采用计算机辅助半自动测量方法测量入组患者动脉瘤形态学参数(包括动脉瘤直径、最大径、宽度、瘤颈宽度、体积、入射角、载瘤动脉直径、表面积、波动指数、非球形指数),计算动脉瘤长宽比、宽颈比、纵横比和尺寸比,并记录动脉瘤位置信息。将多发动脉瘤中破裂责任动脉瘤纳入破裂组,其余动脉瘤纳入未破裂组。采用单因素分析及多因素二元Logistic分析评价破裂组和未破裂组形态学参数及动脉瘤位置信息的差异。结果56例破裂多发动脉瘤患者共126个动脉瘤纳入分析。在形态学方面,直径>5 mm[51.8%(29/56)比15.7%(11/70),P<0.01]、最大径>6 mm[57.1%(32/56)比25.7%(18/70),P<0.01]、入射角>107°[57.1%(32/56)比35.7%(25/70),P=0.016]、宽颈比>1.1[50.0%(28/56)比30.0%(21/70),P=0.022]、纵横比>1.1[46.4%(26/56)比25.7%(18/70),P=0.015]和尺寸比>1.9[57.1%(32/56)比10.0%(7/70),P<0.01]在破裂组与未破裂组之间差异均有统计学意义;在动脉瘤位置方面,破裂组动脉瘤主要位于颈内动脉后交通段[39.3%(22/56)]和大脑中动脉[23.2%(13/56)],而非破裂组动脉瘤主要位于大脑中动脉[28.6%(20/70)]和颈内动脉非后交通段[27.1%(19/70)],两组动脉瘤位置分布差异有统计学意义(P=0.003)。多因素Logistic回归分析结果表明,尺寸比>1.9为动脉瘤破裂的独立危险因素(OR=11.62,95%CI:2.40~56.15;P=0.002)。在动脉瘤位置方面,颈内动脉后交通段动脉瘤的破裂风险高于颈内动脉非后交通段动脉瘤(OR=19.25,95%CI:2.19~169.51;P=0.008)。结论对于多发性颅内动脉瘤,动脉瘤的三维形态学参数中尺寸比>1.9是动脉瘤破裂的独立危险因素,颈内动脉后交通段动脉瘤的破裂风险明显高于颈内动脉非后交通段动脉瘤。 展开更多
关键词 颅内动脉瘤 计算机辅助半自动测量 形态学参数 位置 破裂动脉瘤
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数字技术集中度与企业创新:倒U型关系及转变 被引量:1
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作者 凌士显 凌鸿程 姬梦佳 《科技进步与对策》 北大核心 2024年第2期79-89,共11页
数字化转型可赋予企业创新巨大的新动能,但数字技术种类多、成本高,如何充分借助数字技术促进企业创新是企业关注的焦点。基于2007—2020年沪深A股上市公司数据,采用固定效应模型,考察数字技术集中度对企业创新的影响及作用机制。结果发... 数字化转型可赋予企业创新巨大的新动能,但数字技术种类多、成本高,如何充分借助数字技术促进企业创新是企业关注的焦点。基于2007—2020年沪深A股上市公司数据,采用固定效应模型,考察数字技术集中度对企业创新的影响及作用机制。结果发现,数字技术集中度与企业创新呈显著倒U型关系,表明适度的数字技术集中度能够显著促进企业创新,但过度的数字技术集中度会抑制企业创新。机制分析表明,人力资源整合能力和研发投入强度在数字技术集中度与企业创新间发挥调节效应。随着调节变量增大,倒U型曲线拐点向左偏移,同时倒U型曲线逐渐变得平缓。在调节变量突破拐点临界值后,倒U型曲线转变为U型曲线。由此可见,调节变量增大能够进一步促进企业创新。结论可为深入理解数字技术集中度对企业创新的非线性影响,进而利用调节机制促进企业创新提供经验证据。 展开更多
关键词 企业数字化转型 数字技术集中度 企业创新 人力资源整合能力 研发投入强度
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人类白细胞抗原-DR/CD4^(+)T淋巴细胞白细胞介素6联合降钙素原预测ICU重症急性胰腺炎继发感染效能及对抗菌药物合理使用的指导价值
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作者 高婧 周鹏 +2 位作者 谢晶 王晓英 丛铃娟 《河北医学》 CAS 2024年第5期838-844,共7页
目的:分析人类白细胞抗原-DR/CD4^(+)T淋巴细胞(HLA-DR/CD4^(+))、白细胞介素6(IL-6)及降钙素原(PCT)在ICU重症急性胰腺炎(SAP)继发感染患者中的诊断效能及对抗菌药物合理使用的指导价值。方法:2020年5月至2023年12月在我院ICU收治的SA... 目的:分析人类白细胞抗原-DR/CD4^(+)T淋巴细胞(HLA-DR/CD4^(+))、白细胞介素6(IL-6)及降钙素原(PCT)在ICU重症急性胰腺炎(SAP)继发感染患者中的诊断效能及对抗菌药物合理使用的指导价值。方法:2020年5月至2023年12月在我院ICU收治的SAP患者80例纳入研究。按照是否继发感染将患者分为感染组(n=43)及未感染组(n=37)。收集所有患者临床资料,包括一般资料、实验室指标、抗菌治疗情况。比较两组一般资料及实验室指标,采用Logistic回归分析重症SAP继发感染的独立危险因素,采用受试者工作特征曲线(ROC)分析血清HLA-DR/CD4^(+)、IL-6及PCT预测SAP继发感染的效能。结果:感染组APACHEⅡ评分大于未感染组(P<0.05)。两组性别、年龄、病因、并发症(高血压、2型糖尿病及高脂血症)情况比较无显著差异(P>0.05)。感染组脂肪酶、IL-6及PCT水平高于未感染组(P<0.05),HLA-DR/CD4^(+)水平低于未感染组(P<0.05)。脂肪酶高表达(OR=2.354,95%CI 1.491~3.716)、HLA-DR/CD4^(+)高表达(OR=3.508,95%CI 1.283~9.588)、IL-6高表达(OR=4.284,95%CI 1.469~12.493)及PCT高表达(OR=5.743,95%CI 1.530~21.563)均是SAP继发感染的独立危险因素(P<0.05)。血清HLA-DR/CD4^(+)、IL-6及PCT及三者联合诊断SAP继发感染的AUC值分别为0.809、0.778、0.819及0.959,具有一定预测价值。联合诊断的AUC值及诊断效能明显大于单独HLA-DR/CD4^(+)(z=3.161,P=0.002)、IL-6(z=3.822,P<0.001)及PCT(z=3.346,P=0.001)诊断。局部感染组血清HLA-DR/CD4^(+)水平高于严重感染组,IL-6及PCT水平均低于严重感染组(P<0.05)。局部感染组抗菌药物使用时间、ICU住院时间及总住院时间均较严重感染组显著缩短(P<0.05)。结论:HLA-DR/CD4^(+)高表达、IL-6高表达及PCT高表达均是SAP继发感染的独立危险因素,可有效预测SAP继发感染。 展开更多
关键词 急性胰腺炎 人类白细胞抗原-DR/CD4^(+)T淋巴细胞 白细胞介素6 降钙素原 感染 抗菌药物
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国外石砌民居抗震研究综述
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作者 陈再现 王超 余子聪 《东南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第3期586-598,共13页
为对国外石砌民居抗震研究成果进行综述,首先从Web of Science核心数据集中筛选相关文献205篇,应用CiteSpace软件进行计量分析.随后从试验研究、数值模拟和抗震加固3个方面进行概述.以文献中整理的123组试验数据为例进行统计分析,并对... 为对国外石砌民居抗震研究成果进行综述,首先从Web of Science核心数据集中筛选相关文献205篇,应用CiteSpace软件进行计量分析.随后从试验研究、数值模拟和抗震加固3个方面进行概述.以文献中整理的123组试验数据为例进行统计分析,并对数值模拟模型盲预测能力进行概述.结果表明:国外石砌民居抗震研究过程可分为起步、上升和发展3个阶段,现有承载力计算公式和数值模型均不能准确预测试验结果,力学模型的可靠度需通过试验数据库进行提升,数值模拟中材料和模型的不确定性问题亟待解决;提高石砌民居整体性的构造措施是很好的加固手段,但加固机理和量化还需进一步研究.最后对试验数据库应用、模型不确定性解决方案及抗震加固研究发展方向进行展望. 展开更多
关键词 石砌体 历史民居 面外响应 抗震加固 可视化分析
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基于多查询的社交网络关键节点挖掘算法
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作者 辛国栋 朱滕威 +3 位作者 黄俊恒 魏家扬 刘润萱 王巍 《网络与信息安全学报》 2024年第1期79-90,共12页
关键节点挖掘是复杂网络领域的研究重点和热点。针对社交网络中关键嫌疑人挖掘问题,提出基于多查询的社交网络关键节点挖掘算法。该算法将已知嫌疑人作为查询节点,提取其所在的局部拓扑结构,并计算局部拓扑结构中非查询节点的关键程度,... 关键节点挖掘是复杂网络领域的研究重点和热点。针对社交网络中关键嫌疑人挖掘问题,提出基于多查询的社交网络关键节点挖掘算法。该算法将已知嫌疑人作为查询节点,提取其所在的局部拓扑结构,并计算局部拓扑结构中非查询节点的关键程度,从中选择关键程度较高的节点进行推荐。针对现有方法中关键节点计算复杂度高、已知查询节点信息难以有效利用的问题,提出一个两阶段的基于多查询的社交网络关键节点挖掘算法,整合多查询节点的局部拓扑信息和全局节点聚合特征信息,将计算范围从全局缩减到局部,进而对相关节点的关键程度进行量化。具体而言,利用带重启策略的随机游走算法获得多个查询节点的局部拓扑结构;为了得到节点的嵌入向量,基于graphsage模型构建一种无监督的图神经网络模型,该模型结合节点的自身特征和邻居聚合特征来生成嵌入向量,从而为算法框架的相似度计算提供信息输入。基于与查询节点特征的相似性,衡量局部拓扑中节点的关键程度。实验结果显示,所提算法在时间效率和结果有效性方面均优于传统关键节点挖掘算法。 展开更多
关键词 社交网络 随机游走 图神经网络 节点嵌入向量 关键节点
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公立医院财务会计与内部审计协调监督机制研究
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作者 安波 孙英 祝萍 《卫生经济研究》 北大核心 2024年第7期49-52,共4页
公立医院财务会计与内部审计协调监督在体制机制、目标职能、人才培养、执行规范、技术应用、结果整改等方面存在一些问题,应重塑协调监督组织架构、构建协调监督沟通机制,增强内部监督合力、提升整体监督意识,注重监督人才培养,完善基... 公立医院财务会计与内部审计协调监督在体制机制、目标职能、人才培养、执行规范、技术应用、结果整改等方面存在一些问题,应重塑协调监督组织架构、构建协调监督沟通机制,增强内部监督合力、提升整体监督意识,注重监督人才培养,完善基础设施建设,并加强监督结果利用,从而有效提升公立医院监督效能。 展开更多
关键词 财务会计 内部审计 协调监督
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4种马尾藻附生菌群结构比较研究
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作者 郭战胜 陈雯静 +2 位作者 常丽荣 梁振林 施坤涛 《水生生物学报》 CAS CSCD 北大核心 2024年第4期643-652,共10页
海黍子(Sargassum muticum,SM)、鼠尾藻(Sargassum thunbergii,ST)、铜藻(Sargassum horneri,SH)和海蒿子(Sargassum pallidum,SP)是我国黄渤海常见的大型马尾藻属海藻,研究以靖子湾潮间带4种马尾藻为研究对象,自然海水(W)作为对照,利用... 海黍子(Sargassum muticum,SM)、鼠尾藻(Sargassum thunbergii,ST)、铜藻(Sargassum horneri,SH)和海蒿子(Sargassum pallidum,SP)是我国黄渤海常见的大型马尾藻属海藻,研究以靖子湾潮间带4种马尾藻为研究对象,自然海水(W)作为对照,利用16S rRNA基因扩增子高通量测序技术比较4种马尾藻类附生菌群的结构。研究结果表明,ST附生菌群多样性和物种丰富度最高,SH最低。NMDS(无度量多维标定法)和PERMANOVA分析表明4种马尾藻附生菌的群落结构与海水中微生物群落结构存在显著性差异(P<005),而不同马尾藻之间差异却不显著。LEfse分析共识别出18个Biomarkers,其中W、SH、SM和ST样本分别有9、4、3和2个。变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidota)为4种马尾藻附生菌群的主要优势菌门,相对丰度为80.39%—94.54%;基于属水平和相对丰度前10ASVs的群落结构组成特征表明,4种马尾藻附生菌群结构组成存在明显差异,呈现出宿主特异性。利用Tax4Fun软件对4种马尾藻类附生菌群生态功能进行预测,在一级功能水平上,新陈代谢(Metabolism)、遗传信息处理(Genetic Information Processing)为主要功能;在二级功能水平上,共注释到44个二级代谢通路,其中碳水化合物代谢(Carbohydrate metabolism)相对丰度最高。研究通过比较4种马尾藻附生菌群结构多样性,为进一步深入了解马尾藻属的生态作用提供理论依据。 展开更多
关键词 附生菌群 高通量测序 多样性 功能预测 马尾藻
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“交旅”融合下旅游经济与高速交通协调发展分析——以关中平原城市群为例
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作者 王超 雷婷 +1 位作者 孟晓莎 樊建强 《干旱区地理》 CSCD 北大核心 2024年第6期1015-1025,共11页
关中平原城市群是我国西部旅游资源的重要聚集地,其众多旅游资源开发与社会经济均衡发展亟需高速交通基础设施的支撑。以关中平原城市群为研究对象,基于高速交通和旅游经济评价指标体系,运用熵值法、耦合协调模型等方法,剖析高速交通与... 关中平原城市群是我国西部旅游资源的重要聚集地,其众多旅游资源开发与社会经济均衡发展亟需高速交通基础设施的支撑。以关中平原城市群为研究对象,基于高速交通和旅游经济评价指标体系,运用熵值法、耦合协调模型等方法,剖析高速交通与旅游经济的综合发展水平,并从时空维度分析两者耦合协调的演化态势,最后探究不同高速交通方式与旅游经济协调发展的差异特征。结果表明:(1)关中平原城市群高速交通与旅游经济综合水平整体呈上升态势,且城市群内部发展存在较大差异。(2)城市群高速交通和旅游经济尚未形成明显协调发展格局,其耦合协调度在时序上呈逐步上升趋势,在空间上逐步向“一圈一轴三带”格局演化。(3)不同的高速交通对系统协调程度和旅游经济边际效应存在明显差异,且与旅游经济的耦合协调度也不同。 展开更多
关键词 交旅融合 高速交通 旅游经济 耦合协调度 关中平原城市群
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^(18)F-FDG PET/CT诊断胃癌、前列腺癌双原发癌并多发转移1例
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作者 赵燕霞 于立明 《中国临床医学影像杂志》 CAS CSCD 北大核心 2024年第8期594-596,共3页
病例男,64岁。1周前无明显诱因出现上腹部疼痛不适,为间断性隐痛,程度轻,无他处放射痛,伴有反酸、暖气,无腹胀等其他不适。外院行胃镜检查示:胃体、胃窦交界处后壁黏膜糜烂出血,呈烂肉样改变,胃窦小弯处不规则隆起,直径约2cm,表面糜烂... 病例男,64岁。1周前无明显诱因出现上腹部疼痛不适,为间断性隐痛,程度轻,无他处放射痛,伴有反酸、暖气,无腹胀等其他不适。外院行胃镜检查示:胃体、胃窦交界处后壁黏膜糜烂出血,呈烂肉样改变,胃窦小弯处不规则隆起,直径约2cm,表面糜烂出血。病理:(胃窦小弯侧)腺癌。 展开更多
关键词 胃肿瘤 前列腺肿瘤 正电子发射断层显像计算机体层摄影术 氟脱氧葡萄糖F18
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钢管输电塔挂线节点足尺模型失效模式与承载力提升分析
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作者 翟彬 李素超 +3 位作者 张丽娟 徐再根 王志远 毛晨曦 《地震研究》 CSCD 北大核心 2024年第1期1-9,共9页
针对特高压钢管输电塔挂线位置节点在极端荷载下的安全性,提出了挂线节点双侧挂线板协同受力的构造改进措施,并对比研究两种挂线节点的极限承载力与失效模式。通过足尺挂线节点处的承载力试验与有限元分析,比较挂线节点在单侧板受力、... 针对特高压钢管输电塔挂线位置节点在极端荷载下的安全性,提出了挂线节点双侧挂线板协同受力的构造改进措施,并对比研究两种挂线节点的极限承载力与失效模式。通过足尺挂线节点处的承载力试验与有限元分析,比较挂线节点在单侧板受力、双侧板受力情况下的应力分布与承载能力,分析传力螺母与挂线板之间的合理初始间距。结果表明:双侧受力时两侧挂线板均发生弯曲破坏,受力形式更加合理,节点板应力分布更加均匀,挂线点的屈服承载力可以提升一倍以上,传力螺母与挂线板之间的合理初始间隙为2~4 mm。 展开更多
关键词 特高压输电塔 挂线节点 承载力 足尺试验 有限元模拟 传力螺母
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中国高新技术产品进口关税减让的经济效应
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作者 王小梅 安文洁 《中国软科学》 CSCD 北大核心 2024年第6期43-53,共11页
降低高新技术产品进口关税是中国践行扩大开放承诺的有力措施,对于以高新技术产业发展推动高水平科技自立自强具有重要意义。运用可计算局部均衡模型,从产业层面考察了中国高新技术产品进口关税减让的经济影响。研究发现:中国高新技术... 降低高新技术产品进口关税是中国践行扩大开放承诺的有力措施,对于以高新技术产业发展推动高水平科技自立自强具有重要意义。运用可计算局部均衡模型,从产业层面考察了中国高新技术产品进口关税减让的经济影响。研究发现:中国高新技术产品进口关税税率下调对进口的促进效应大于出口,其效应随降税幅度的提高而递增,且现有关税税率越高,降税的贸易效应越大;中国高新技术产品的内销额和消费者价格将减少,但生产者价格和产量变化不大;中国高新技术产业的消费者剩余大幅提高,生产者剩余变化幅度有限,但政府进口关税收入下降明显,所以高新技术产品的社会净福利将减少,其中广播、电视和通讯设备类产品的净福利损失最大,办公、会计和计算机器类产品与航空航天产品的净福利损失较小。研究结果可为中国高新技术产品关税政策调整提供依据,也能为中国主动扩大进口政策制定提供参考。 展开更多
关键词 高新技术产品 关税减让 经济效应 可计算局部均衡模型
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