云南省边境地区州市旅游竞争力差异与整合研究

云南作为我国的旅游大省,其州市旅游竞争力水平对区域旅游业的生存和发展至关重要。基于旅游现状竞争力、旅游基础环境竞争力和旅游潜在竞争力三大维度构建了旅游竞争力量化测评指标体系,运用因子分析法对云南8个边境州市旅游竞争力水平层级进行了量化测评。研究表明:(1)云南边境地区8州市旅游发展竞争力层级分为较强旅游竞争力区、一般旅游竞争力区和较弱旅游发展竞争力区三种类型;红河、临沧属于较强旅游竞争力区,西双版纳、德宏、普洱属于一般旅游竞争力区,文山、保山、怒江属于较弱旅游发展竞争力区;(2)在空间布局形态方面,较强旅游竞争力发展州市呈现"分散状"布局,主要集中于滇南地区,其余非较强旅游竞争力区州市呈现"趋同俱乐部现象"空间布局。整体上旅游竞争力水平层级形成了以滇南地区为核心向周边州市等外缘区域发展的"核心—边缘"式空间发展格局;(3)边境各州市旅游资源呈现区块聚焦性,旅游形象和客源市场定位仍存在雷同现象,且边境各州市旅游业发展水平极化效应明显。为此提出了旅游产品及资源、旅游市场、旅游空间及旅游线路整合和完善旅游管理机制等应对策略。     

测绘资料管理信息系统的设计及问题讨论

本系统拟采用以 ARC/INFO为地理信息系统开发平台 ,VISUALFOX PRO为其相关的数据库管理系统 ,用 VISUAL BASIC为数据库的前台开发工具。开发测绘资料管理信息系统 ,使其具有强大的空间查询、计算和分析的功能。为测绘资料的管理和应用提供方便、高效的手段。     

一种计算高铁沉降预测常用模型参数的新方法

高速铁路的修建需要对线下构筑物进行沉降观测和沉降评估。本文深入研究了常用的5种预测函数模型及其参数的一般解算方法,并基于Matlab软件的lsqcurvefit函数提出了一种新的参数解算方法,最后通过实际工程数据检验,证明了该方法有较高的可行性和精确度。     

The growth mechanism of the aragonitic stalagmite laminae from Yunnan Xianren Cave,SW China revealed by cave monitoring

Duan, W., Cai, B., Tan, M., Liu, H. & Zhang, Y. 2012 (January): The growth mechanism of the aragonitic stalagmite laminae from Yunnan Xianren Cave, SW China revealed by cave monitoring. Boreas, Vol. 41, pp. 113–123. 10.1111/j.1502‐3885.2011.00226.x. ISSN 0300‐9483. Stalagmites from Xianren Cave in Yunnan Province, SW China have visible bands of alternating compact and porous sub‐layers, which have recently been demonstrated to be annual: the compact sub‐layer consists of elongated columnar aragonites with a general longitudinal orientation (parallel to the vertical growth axis), while the porous sub‐layer is composed mainly of needle aragonites forming radiating masses. In order to understand the growth mechanism of this type of stalagmite laminae, factors that could determine the growth rate and crystal structures of modern carbonates, such as cave‐air temperature, CO₂ concentration, drip rate and the hydrochemical parameters of drip water, have been monitored systematically. In this study, we selected five active drip sites to monitor for two years at a monthly frequency. Based on the monitoring results and the analyses of stalagmite laminae, we conclude that the compact sub‐layer forms in winter, when the drip rate is moderate and the degassing is slow, continuous and prolonged. The porous sub‐layer forms in early spring, when the drip rate is lower and Mg/Ca is higher than that during the formation of the compact sub‐layer. We also found exceptionally some calcite laminae. Furthermore, we discovered modern calcites precipitating at all study sites in the first hydrologic year when the rainfall was very abundant. Therefore, it is suggested that the occurrence of localized calcites in an aragonitic stalagmite indicates an interval of higher rainfall.     

温度对土壤介电常数的影响规律研究北大核心CSCD

介电常数是频域反射法测定土样含水率的关键参数之一。为获取温度对土壤介电常数的影响规律,利用矢量网络分析仪测得不同含水率、含盐量的试样在不同试验温度下的介电常数。通过分析土样介电常数随不同因素的变化规律,最后建立了介电常数与温度的关系。结果表明:温度对土样介电常数的影响主要表现在冰水剧烈相变阶段。当温度低于某一温度或者高于冻结温度后,介电常数受温度的影响较小。负温条件下,土样介电常数随含盐量增大而增大。引入阶梯函数建立的三阶段模型,可有效描述土样介电常数随温度的变化规律。     

循环冻融下寒区工程常用保温材料性能变化试验研究北大核心CSCD

保温材料广泛应用于寒区工程的诸多领域。然而,在服役过程中,保温材料往往会受到浸水、冻融和盐蚀等多场耦合的循环作用,导致其保温、防水和强度等物理力学性能出现不同程度的退化。目前,保温材料的类型非常多,但其性能和耐久性有所不同,因此科学合理地选择保温材料不仅关系到其长期保温效果,同时对于工程构筑物的长期稳定性具有重要的意义。针对循环冻融作用,选取寒区工程中常用的4种保温材料[聚酚醛(FLK)、聚氨酯(PU)、聚苯乙烯挤塑板(XPS)和聚苯乙烯发泡板(EPS)]开展了浸纯水、浸盐水和干燥状态下的室内冻融循环试验,对经历了不同冻融次数的样品进行了表观密度、吸水率、导热系数、压缩强度、弯曲强度和微观结构系列测试。结果表明:浸润作用对保温材料物理力学性质影响显著,亲水性材料FLK的保温和力学性能退化显著,而憎水性材料PU、XPS和EPS变化相对较小。干燥条件下,冻融循环作用对FLK、XPS和EPS吸水率以及FLK的导热系数影响量值可观,但对4种保温材料的压缩和弯曲强度影响不大。浸纯水和盐水条件下,经历30次冻融循环后,FLK的导热系数增加约50%,弯曲强度降低超过0.3%,EPS的压缩强度降低超过10%。浸盐水后保温材料经历冻融循环作用后其物理力学性能退化程度与浸纯水条件下有所不同,该差异值得关注。通过扫描电镜图像能够识别4种保温材料的孔隙尺寸、孔隙致密度和固体颗粒胶结方式,但对经历冻融循环作用后的变化难以识别和量化。基于试验结果,结合寒区交通工程应用场景,分析了4种保温材料的冻融耐久性,以期服务于寒区交通工程保温材料的合理应用。     

卫星资料揭示的青藏高原对流层上层温度气候演变趋势特征

利用1982—2016年MSU/AMSU-A亮温资料,分析了青藏高原地区对流层上层温度的气候趋势及其演变特征,并利用ERA-Interim和NCEP-R2再分析资料的相应高度大气温度资料进行了对比分析。结果表明,青藏高原地区对流层高层卫星亮温资料总体表现为逐渐增暖现象,这与再分析资料的对应层次大气温度变化有很好的相似性。基于集合经验模式分解方法 EEMD的非线性趋势分析表明,青藏高原地区对流层上层亮温的增温首先出现在青藏高原中部,随着时间演变,增温现象逐渐向青藏高原四周扩散,最后在整个青藏高原地区都出现了一致增温现象。相比于NCEP-R2再分析资料而言,ERA-Interim再分析资料300 h Pa大气温度的演变趋势与观测亮温有很好的相似性,只是增温现象是首先在青藏高原附近,随着时间推移,增温现象逐步向周边地区扩张,最终整个青藏高原地区出现了整体升温现象。但是NCEP-R2再分析资料则是与上述两种资料的温度演变特征有很大的差异,其300 h Pa高度大气温度在前20年表现为明显的降温特征,在最近10年才出现了增温,并逐步向周边地区扩张的现象。     

试论山地高梯度效应——以横断山地的自然-人文景观效应为例

山地是地球表面具有显著起伏度和坡度的三维地貌体,由于自然要素及受其影响的人类活动随海拔高度和相对高度的变化而产生了梯变现象,形成了山地高梯度效应.山地高梯度效应是表征山地随海拔高度和相对高差变化而导致的自然-人文景观的梯次变化现象,是山地地域系统演变的综合集成效应.横断山区是我国典型的高山峡谷区,山地高梯度效表现显著.山地高梯度效应的内涵包括了能量(山地重力势能、热能、生物质能等)高梯度效应、气候高梯度效应、气候地貌高梯度效应、自然带谱高梯度效应、人文社会经济活动(如土地利用等)高梯度效应、人居环境高梯度效应等.山地高梯度效应研究是响应IGBP、IHDP、GTOS等提出的“全球变化与山区-山地研究倡议”的重要行动,也是山地综合研究的重要途径和方法,对山区自然资源利益、社会经济发展、生态环境建设、山区可持续发展等有着重要的意义和价值.     

Mineral Chemistry of Peridotites from Paleozoic, Mesozoic and Cenozoic Lithosphere: Constraints on Mantle Evolution beneath Eastern China

Major- and trace-element data on the constituent minerals ofgarnet peridotite xenoliths hosted in early Paleozoic (457–500Ma) kimberlites and Neogene (16–18 Ma) volcanic rockswithin the North China Craton are compared with those from thepre-pilot hole of the Chinese Continental Scientific DrillingProject (CCSD-PP1) in the tectonically exhumed Triassic (220Ma) Sulu ultrahigh-pressure (UHP) terrane along its southernmargin. P–T estimates for the Paleozoic and Neogene peridotitexenoliths reflect different model geotherms corresponding tosurface heat flows of 40 mW/m² (Paleozoic) and 80 mW/m² (Neogene).Garnet peridotite xenoliths or xenocrysts from the Paleozoickimberlites are strongly depleted, similar to peridotites fromother areas of cratonic mantle, with magnesium olivine (meanFo_92.7), Cr-rich garnet and clinopyroxene with high La/Yb. Garnet(and spinel) peridotite xenoliths hosted in Neogene basaltsare derived from fertile mantle; they have high Al₂O₃ and TiO₂contents, low-Mg-number olivine (mean Fo_89.5), low-Cr garnetand diopside with flat rare earth element (REE) patterns. Thedifferences between the Paleozoic and Neogene xenoliths suggestthat a buoyant refractory lithospheric keel present beneaththe eastern North China Craton in Paleozoic times was at leastpartly replaced by younger, hotter and more fertile lithosphericmantle during Mesozoic–Cenozoic times. Garnet peridotitesfrom the Sulu UHP terrane have less magnesian olivine (Fo_91.5),and lower-Cr garnet than the Paleozoic xenoliths. The diopsideshave low heavy REE (HREE) contents and sinusoidal to light REE(LREE)-enriched REE patterns. These features, and their highMg/Si and low CaO and Al₂O₃ contents, indicate that the CCSD-PP1peridotites represent a moderately refractory mantle protolith.Details of mineral chemistry indicate that this protolith experiencedcomplex metasomatism by asthenosphere-derived melts or fluidsin Mesoproterozoic, and subsolidus re-equilibration involvingfluids/melts derived from the subducted Yangtze continentalcrust during UHP metamorphism in the early Mesozoic. Tectonicextension of the subcontinental lithospheric mantle of the NorthChina Craton and exhumation of the Sulu UHP rocks in the earlyMesozoic induced upwelling of the asthenosphere. Peridotitessampled by the Neogene basalts represent newly formed lithospherederived by cooling of the upwelling asthenospheric mantle inJurassic–Cretaceous and Paleogene time. KEY WORDS: garnet peridotite xenoliths; North China Craton; lithospheric thinning; Sulu UHP terrane; UHP lithosphere evolution; mantle replacement     

山地气候梯变效应与特色气候资源的开发利用

从空气中的氧、二氧化碳、水汽、固体粒子含量以及大气压力、接受的太阳辐射、光照时数、所获得热量、降水量等因素介绍了山地气候梯变效应的具体表现,分析了山地气候梯度效应对生态环境及人类活动的影响。从山地气候梯变效应的实际状况出发,通过分析山地气候资源的特点,指出人类应遵循生态系统、自然保护、景观和谐、因地制宜等原则,挖掘山地气候旅游资源、多样化气候资源和气候"小生境"等气候资源,突显其特色,发展异于平地的农业生产、旅游活动等,将有助于山地特色气候资源的充分利用。