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基于百度指数的乡村旅游需求时空特征及其影响因素研究

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世界地理研究 2024年第5期33卷 177-188页

作者：刘海朦田小波曹婷婷华中师范大学城市与环境科学学院武汉430079 中国旅游研究院武汉分院武汉430079 郑州科技学院工商管理学院郑州450064

互联网搜索行为是用户需求和行为惯性在虚拟空间的直观表达,为长时间序列、大空间尺度旅游需求分析提供了新的视角。论文以2011—2020年我国31个省级行政区乡村旅游9个关键词的百度指数为数据基础,利用空间自相关、地理探测器等方法分... 详细信息

互联网搜索行为是用户需求和行为惯性在虚拟空间的直观表达,为长时间序列、大空间尺度旅游需求分析提供了新的视角。论文以2011—2020年我国31个省级行政区乡村旅游9个关键词的百度指数为数据基础,利用空间自相关、地理探测器等方法分析了我国乡村旅游需求的时空演变特征及其影响因素。研究发现:(1)乡村旅游需求十年间总体呈“倒U”形变化形态,并表现出快速发展期、波动发展期的非线性阶段特征;年内呈现出“两峰两谷”变化特征,淡、旺季和周末效应比较明显。(2)乡村旅游需求整体上呈集聚分布状态,集聚效应随年际变化略有波动;局部空间上呈现东高西低的梯度递减格局,且此特征在十年间基本保持稳定。(3)5个因子对乡村旅游需求时空特征有持续显著的影响,其解释力表现为地区生产总值>星级饭店数量>人口总量>公路密度>国家级乡村旅游点数量,其他因子解释力相对较低或年际变动较大。论文借助网络大数据从宏观层面揭示了乡村旅游需求的时空演变规律及其影响因素,为优化产业布局、推进乡村旅游供需有效对接等提供了理论指导和实践借鉴。

关键词：乡村旅游需求时空特征百度指数地理探测器影响因素

Crustal velocity structure in the Emeishan large igneous province and evidence of the Permian mantle plume activity

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Science China Earth Sciences 2015年第7期58卷 1133-1147页

作者： XU Tao ZHANG ZhongJie LIU BaoFeng CHEN Yun ZHANG MingHui tian xiaobo XU YiGang TENG JiWen State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences CAS Center for Excellence in Tibetan Plateau Earth Sciences Geophysical Exploration Center China Earthquake Administration University of Chinese Academy of Sciences State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences

The Emeishan large igneous province(ELIP) in SW China is interpreted to be associated with an ancient mantle plume. Most of the constraints on the role of mantle plume in the generation of the Emeishan flood basalts were provided by geological and geochemical methods, but the geophysical investigation is very limited. In order to better understand the deep structure and features of ELIP, we have studied the crustal velocity structure using the data acquired from the Lijiang-Panzhihua-Qingzhen wide-angle seismic profile. This profile crosses the three sub-zones of the ELIP(the inner, intermediate, and outer zones), divided based on the differential erosion and uplift of the Maokou limestone. The results provided by the active source seismic experiment demonstrate:(1) The average depth of the crystalline basement along the profile is about 2 km.(2) The middle crust in the Inner Zone is characterized by high-velocity anomalies, with the average velocity of 6.2-6.6 km/s, which is about 0.1– 0.2 km/s higher than the normal one. The velocity of the lower crust in the inner zone is 6.9-7.2 km/s, higher than those observed in the intermediate and outer zones(6.7-7.0 km/s). Relatively low velocity anomalies appear in the upper, middle and lower crusts near the junction of the inner zone and intermediate zone, probably due to the effect of the Xiaojiang fault(XJF).(3) The average velocity of the crust is comparatively low on both sides of XJF, especially on the east side, and the average velocity of the consolidated continental crust is also low there. This may suggest that the XJF extends at least down to 40 km deep, even beyond through the crust.(4) The depth to the Moho discontinuity decrease gradually from 47-53 km in the inner zone, via 42-50 km in the intermediate zone to 38-42 km in the outer zone. In the inner zone, the Moho uplifts locally and the(consolidated) crust is characterized by high-velocity anomalies, which are likely related to intensive magma intrusion and underplating associated with melting of plume

关键词：地壳速度结构峨眉山大火成岩省二叠纪地幔热柱峨眉山地幔柱证据峨眉山玄武岩地球物理调查

A high resolution lithospheric magnetic field model over China

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Science China Earth Sciences 2013年第10期56卷 1759-1768页

作者： OU JiaMing DU AiMin E.THBAULT XU WenYao tian xiaobo ZHANG TieLong Institute of Geology and Geophysics Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences Equipe de Géomagnétisme Institut de Physique du Globe de ParisSorbonne 4 Paris CitéINSU/CNRS1 rue Jussieu75005 ParisFrance Space Research Institute Austrian Academy of Sciences

CHAMP satellite data and ground-based magnetic observations are used and combined to map the lithospheric magnetic field over China by means of the revised spherical cap harmonic analysis(R-SHCA)modeling technique.The magnetic field is described to a spatial resolution of 150 km at the mean Earth’s radius,which represents a good compromise between the resolutions afforded by surface and satellite data.We compare the magnetic anomalies modeled at the regional scale with composite regions containing large-scale of tectonic structures.These regions,including the Tarim Basin and the Tibetan Plateau,are correlated with regional magnetic anomalies at satellite altitude but contain a significant number of small-scale and complex magnetic structures at the mean Earth’s radius.These magnetic anomalies are globally consistent with the known geological features in China but also offer a way to delineate the contours of the geological blocks and to discuss the connection between magnetic anomalies and the heat flow distribution in this region.

关键词：磁场模型高分辨率岩石圈中国区域磁异常卫星数据建模技术平均半径

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地震反射剖面揭示阿尔泰山陆内逆冲造山机制

Science Bulletin 2024年第11期69卷 1757-1766页

作者：张蕾赵连锋赵亮谢小碧田小波肖文交姚振兴 Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Institute of Geophysics and Planetary Physics University of California at Santa CruzCA 95064USA Xinjiang Institute of Ecology and Geography Chinese Academy of SciencesUrumqi 830011China

The Altai orogen is a typical intracontinental orogen in Central Asia that experienced far-field deformation associated with Indian-Eurasian plate convergence. This region is characterized by uplift comparable to that of the tianshan Mountains but has a distinct strain rate. Half of the Indo-Asia strain is accommodated by the tianshan Mountains, whereas the Altai Mountains accommodates only 10%. To elucidate how the Altai Mountains produced such a large amount of uplift with only one-fifth of the strain rate of the tianshan Mountains, we constructed a detailed crustal image of the Altai Mountains based on a new 166.8-km deep seismic reflection profile. The prestack migration images reveal an antiform within the Erqis crust, an ~10 km Moho offset between the Altai arc and the East Junggar area, and a major south-dipping(30° dip) thrust in the lower crust beneath the Altai Mountains, which is connected to the Moho offset. The south-dipping thrust not only records the southward subduction of the Ob-Zaisan Ocean in the Paleozoic but also controlled the Altai deformation pattern in the Cenozoic with the Erqis antiform. The Erqis antiform prevented the extension of deformation to the Junggar crust. The southdipping thrust in the lower crust of the Altai area caused extrusion of the lower crust, generating uplift at the surface, thickening of the crust, and steep(~10 km) Moho deepening in the Altai Mountains. This process significantly widened the deformation zone of the Altai Mountains. These findings provide a new geodynamic model for describing how inherited crustal structure controls intraplate deformation without strong horizontal stress.

关键词： Altai mountains Deep seismic reflection profile Subduction-accretion process Intraplate deformation pattern

血清MMP2/TIMP2比值与老年2型糖尿病患者并发AS的相关性分析

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安徽医学 2024年第1期45卷 59-64页

作者：田小波梁振花蔡天聪万宁市人民医院综合内科海南万宁571500

目的探讨血清基质金属蛋白酶-2/金属蛋白酶组织抑制因子-2(MMP2/TIMP2)比值与老年2型糖尿病(T2DM)患者并发主动脉硬化(AS)之间的关系。方法回顾性分析2022年1月至2023年4月万宁市人民医院收治的180例初次诊断为T2DM的老年患者的临床资料... 详细信息

目的探讨血清基质金属蛋白酶-2/金属蛋白酶组织抑制因子-2(MMP2/TIMP2)比值与老年2型糖尿病(T2DM)患者并发主动脉硬化(AS)之间的关系。方法回顾性分析2022年1月至2023年4月万宁市人民医院收治的180例初次诊断为T2DM的老年患者的临床资料,并根据是否并发AS[颈动脉-股动脉脉搏波传导速度(cfPWV)>10 m/s]分为AS组(n=69)和非AS组(n=111)。另选取同时期来院体检健康者采用倾向性评分法匹配90例为对照组。比较3组对象的一般资料、实验室指标以及血清MMP2、TIMP2水平和MMP2/TIMP2比值。采用Spearman相关分析探究老年T2DM患者cfPWV与各项指标的相关性。采用多因素logistic回归模型分析,老年T2DM患者并发AS的影响因素。绘制受试者工作特征(ROC)曲线,分析并比较MMP2/TIMP2比值与多指标联合检测对老年T2DM患者并发AS的诊断价值。结果非AS组稳态模型胰岛素抵抗指数(HOMA-IR)、血清三酰甘油(TG)、MMP2水平及MMP2/TIMP2比值高于对照组,血清TIMP2水平低于对照组,差异有统计学意义(P<0.05)。AS组年龄、合并高血压比例高于非AS组(P<0.05)。AS组HOMA-IR、血清TG、MMP2水平及MMP2/TIMP2比值高于对照组和非AS组,血清TIMP2水平低于对照组和非AS组,差异均有统计学意义(P<0.05)。相关性分析结果显示,非AS组患者的cfPWV与HOMA-IR、TC、LDL-C、MMP2、MMP2/TIMP2比值呈正相关(r=0.217、0.264、0.216、0.197、0.703,P<0.05),与TIMP2呈负相关(r=-0.524,P<0.01);AS组患者cfPWV与MMP2、MMP2/TIMP2比值呈正相关(r=0.659、0.857,P<0.01),与TIMP2呈负相关(r=-0.532,P<0.01)。logistic回归分析显示,年龄增长(OR=1.108,95%CI:1.022~1.201,P=0.012)、高血压病(OR=2.877,95%CI:1.174~7.051,P=0.021)及MMP2/TIMP2比值升高(OR=5.147,95%CI:2.392~11.074,P<0.001)是老年T2DM患者并发AS的的独立危险因素。ROC曲线分析结果显示,MMP2/TIMP2比值及多指标联合检测诊断老年T2DM患者并发AS的曲线下面积分别为0.850(95%CI:0.789~0.899,P<0.01)和0.886(95%CI:0.831~0.929,P<0.01),灵敏度分别为73.91%、82.61%,特异度分别为89.19%、82.88%,约登指数分别为0.631、0.655。多指标联合检测的诊断效能明显大于MMP2/TIMP2比值,差异具有统计学意义(Z=2.233,P=0.026)。MMP2/TIMP2比值诊断老年T2DM患者并发AS的最佳截断值为3.23。结论MMP2/TIMP2比值升高为老年T2DM患者并发AS的独立危险因素,对老年T2DM并发AS的诊断有辅助价值,多指标联合检测可提高诊断效能。

关键词：糖尿病,2型基质金属蛋白酶-2/金属蛋白酶组织抑制因子-2比值主动脉僵硬度脉搏波分析

Uplifting mechanism of the Tibetan Plateau inferred from the characteristics of crustal structures

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Science China Earth Sciences 2023年第12期66卷 2770-2790页

作者： Xiaofeng LIANG Ling CHEN xiaobo tian Yang CHU Wentao LI State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBejing 100029China Innovation Academy of Earth Science Chinese Academy of SciencesBejing 100029China School of Earth and Planetary Science University of Chinese Academy of SciencesBeiing 100049China

The Tibetan Plateau has been known for its highest elevation and thickest crust on earth,and become a key region for comprehending the rheology and tectonic evolution of continental plates and associated dynamic processes.Over the past years,numerous geophysical studies have been conducted to explore the deep structure of the Tibetan Plateau,resulting in significant advancements in understanding the formation and growth of the Plateau.This paper aims to provide a comprehensive summary and discussion of the geophysical observations and underlying mechanisms of the plateau uplift.First,major relevant tectonic models are reviewed,and the corresponding features of crustal structures and related deformation are presented.Then,recent observations,including the identification of a high-velocity layer in the lower crust of the Lhasa block,the spatial distribution of crustal channel flow,and the decoupling of shallow and deep crustal deformation,are synthesized to gain insights into the crustal structures,and multidisciplinary data are integrated to discuss the potential mechanisms of the plateau uplift.Lastly,some pertinent suggestions are put forward for future research on the Tibetan Plateau.

关键词： Tibetan Plateau Crustal structure Moho doublet Uplift of the plateau Crustal channel flow

Spectral purification improves monitoring accuracy of the comprehensive growth evaluation index for film-mulched winter wheat

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Journal of Integrative Agriculture 2024年第5期23卷 1523-1540页

作者： Zhikai Cheng xiaobo Gu Yadan Du Zhihui Zhou Wenlong Li xiaobo Zheng Wenjing Cai tian Chang Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid AreasMinistry of Education/Northwest A&F University Yangling712100China

In order to further improve the utility of unmanned aerial vehicle(UAV)remote-sensing for quickly and accurately monitoring the growth of winter wheat under film mulching, this study examined the treatments of ridge mulching,ridge–furrow full mulching, and flat cropping full mulching in winter wheat.Based on the fuzzy comprehensive evaluation (FCE) method, four agronomic parameters (leaf area index, above-ground biomass, plant height, and leaf chlorophyll content) were used to calculate the comprehensive growth evaluation index (CGEI) of the winter wheat, and 14 visible and near-infrared spectral indices were calculated using spectral purification technology to process the remote-sensing image data of winter wheat obtained by multispectral UAV.Four machine learning algorithms, partial least squares, support vector machines, random forests, and artificial neural network networks(ANN), were used to build the winter wheat growth monitoring model under film mulching, and accuracy evaluation and mapping of the spatial and temporal distribution of winter wheat growth status were carried out.The results showed that the CGEI of winter wheat under film mulching constructed using the FCE method could objectively and comprehensively evaluate the crop growth status.The accuracy of remote-sensing inversion of the CGEI based on the ANN model was higher than for the individual agronomic parameters, with a coefficient of determination of 0.75,a root mean square error of 8.40, and a mean absolute value error of 6.53.Spectral purification could eliminate the interference of background effects caused by mulching and soil, effectively improving the accuracy of the remotesensing inversion of winter wheat under film mulching, with the best inversion effect achieved on the ridge–furrow full mulching area after spectral purification.The results of this study provide a theoretical reference for the use of UAV remote-sensing to monitor the growth status of winter wheat with film mulching.

关键词： mulched winter wheat machine learning fuzzy comprehensive evaluation comprehensive growth evaluation index unmanned aerial vehicle

Preface of the Special Issue on Symplectic Geometry and Mathematical Physics

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Acta Mathematica Sinica,English Series 2024年第1期40卷 1-2页

作者： Huijun Fan xiaobo Liu Gang tian Peking University BeijingChina

Symplectic geometry is a branch of differential geometry and differential topology and has its origins in the Hamiltonian formulation of classical mechanics.In the last few decades,symplectic geometry has experienced enormous progress and has had interactions with many other branches of mathematics,including enumerative geometry,low-dimensional topology,mathematical physics,Hamiltonian dynamics,integrable systems etc..

关键词： geometry topology Hamiltonian

基于色谱-质谱联用技术的贝类中农药残留检测方法研究进展

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实验与分析 2024年第1期2卷 39-44页

作者：朱富强田晓波康琳刘红王义春张国康滨州市检验检测中心山东滨州256600 滨州市沾化区科技创新发展研究中心山东滨州256800 滨州职业学院山东滨州256603

贝类质量安全关系着贝类产业兴衰和人民健康,以往研究多关注于贝类中重金属、兽药残留、贝类毒素、致病菌等质量安全指标的检测,对于贝类中农药残留的检测方法的综述相对少见。目前,农药污染问题造成的贝类质量安全隐患不容小觑,本文综... 详细信息

贝类质量安全关系着贝类产业兴衰和人民健康,以往研究多关注于贝类中重金属、兽药残留、贝类毒素、致病菌等质量安全指标的检测,对于贝类中农药残留的检测方法的综述相对少见。目前,农药污染问题造成的贝类质量安全隐患不容小觑,本文综述了近年来贝类中农药残留的色谱-质谱联用检测技术的研究进展,以期为贝类中农药残留风险监测与评价研究提供技术参考。

关键词：贝类农药残留检测进展