Integrated indicators-based gradation of cultivated land quality in mountainous region of Southwestern China

1 Introduction The gradation of cultivated land is to assess the suitability of cultivated land for agricultural production in terms of natural and economic prop-erties of land (Feng et al. 2004). It can be used to evaluate sustainability of land use and …     

基于主体功能区约束的大气污染物总量控制目标分配研究

考虑经济发展水平、污染物排放现状、污染物治理水平、空气质量,特别是国家主体功能区环境目标约束等因素,构建大气污染物排放总量分配的指标体系,用改进的等比例分配方法对2015年国家SO2,NOx总量控制目标进行区域分配。分配结果表明:SO2和NOx削减量大的省份主要集中在华北平原及其周围地区,这些地区污染物排放量大、空气质量较差;削减比例较大的地区主要集中在西部地区以及北京、天津2个直辖市,这些地区单位GDP能耗高、工业污染物去除率低、空气质量差;削减量相对较小的地区主要集中在西南和南部一些省份;削减比例较小的地区主要集中在中南部和南部几个省份,这些地区污染物排放量相对较少,空气质量好于其他省份。     

Geophysical constraints on mesozoic disruption of North China Craton by underplating‐triggered lower‐crust flow of the Archaean lithosphere

The mechanism of the disruption, both lithospheric thinning and oceanization of the commonly accepted long‐term‐stable Archaean craton, is still an open question. The available models, all imply a bottom to top process. With the construction of a 1660‐km‐long transect across the eastern North China Craton (NCC), we demonstrate that both the P‐wave velocity and density in the lowermost crust beneath the central section are significantly higher than in the corresponding parts of the south and north sections on the transect. These features are interpreted as geophysical signature of lower crustal underplating, which supplies sufficiently high gravitational potential energy to trigger lateral flow of the lower crust. This magma underplating‐triggered bilateral lower crust flow may facilitate the lithospheric thinning by means of asthenosphere upwelling and decompression melting, which infill the gap produced by the lower crust flow. The underplating‐triggered lower crustal flow can provide an alternative mechanism to explain the NCC lithosphere disruption, which highlights the crustal feedback to Archaean lithosphere disruption, from top to bottom.     

大跨度三塔斜拉桥主塔施工测量技术研究

蒙华铁路洞庭湖大桥是世界最大跨度的三塔铁路斜拉桥,对大桥主塔的测量精度要求极高。本文主要介绍了蒙华铁路洞庭湖三塔斜拉桥主塔的施工测量控制技术,针对斜拉桥塔座、塔柱、索导管等关键结构的控制测量,结合洞庭湖大桥的工程施工特点进行研究,并对三维极坐标放样及全站仪天顶测距法进行精度分析。     

Grid pattern recognition in road networks using the C4.5 algorithm

Pattern recognition in road networks can be used for different applications, including spatiotemporal data mining, automated map generalization, data matching of different levels of detail, and other important research topics. Grid patterns are a common pattern type. This paper proposes and implements a method for grid pattern recognition based on the idea of mesh classification through a supervised learning process. To train the classifier, training datasets are selected from worldwide city samples with different cultural, historical, and geographical environments. Meshes are subsequently labeled as composing or noncomposing grids by participants in an experiment, and the mesh measures are defined while accounting for the mesh’s individual characteristics and spatial context. The classifier is generated using the C4.5 algorithm. The accuracy of the classifier is evaluated using Kappa statistics and the overall rate of correctness. The average Kappa value is approximately 0.74, which corresponds to a total accuracy of 87.5%. Additionally, the rationality of the classifier is evaluated in an interpretation step. Two other existing grid pattern recognition methods were also tested on the datasets, and comparison results indicate that our approach is effective in identifying grid patterns in road networks.     

不同地形条件地面同步光谱定标场对比研究

利用美国ASD公司的FieldSpec Pro FR地面波谱仪,选择5°视场角探头和135cm探头距测试地物高度,开展0°、5°、10°、15°、20°等五种不同地形坡度明、暗地物自然定标场地面波谱测试。通过对比研究不同地形坡度具代表性、能真实反映被测试目标平均自然性的各波谱测试点波谱曲线特征,得出0°、5°地形坡度获取的波谱曲线连续、平滑,信噪比高,没有混入大气水气吸收、仪器噪声等因素导致的剧烈波动、跳跃现象或尖锐锯齿状噪声,波谱特征明显,吸收峰最小值位置清晰可辨,各波谱测试点波谱曲线变化幅度小,整体反射率值变化小,Fe~(2+)、Fe~(3+)、Al-OH、Mg-OH、CO_3~(2-)等分子基团与离子波谱的诊断性波谱特征位置清晰可辨。因此0°和5°坡度地形条件获取的地面同步自然场光谱定标波谱曲线,可以满足航空高光谱遥感数据的大气校正、光谱重建和空、地回归分析等所需的地面波谱数据要求。     

金川铜镍矿床中新生代抬升冷却过程：来自裂变径迹的证据

本文基于热年代学理论,利用锆石和磷灰石裂变径迹测年数据及对磷灰石热史的模拟,分析探讨金川铜镍矿床在中新生代的抬升冷却过程,认为金川超基性岩体自中生代以来一直处于持续的冷却抬升阶段,且在中侏罗世和晚白垩世早期经历了两期快速的抬升冷却事件,推断此事件与青藏高原后期活动时间相对应,证明金川岩体受到该事件的远程效应波及,致使该矿床遭受了一定的改造。     

钟姑地区典型矿床的重磁找矿模式

钟姑地区位于宁芜中生代火山岩盆地南段,已发现有白象山铁矿等多个大型铁矿,是长江中下游成矿带以玢岩型铁矿为主的矿集区。本文以钟姑地区实测岩石物性参数为桥梁,以实测重磁数据为基础,分析了该区白象山铁矿、钟九铁矿和云楼铁矿的重磁场分布特征,并根据典型矿区已知地质条件,运用成熟的2.5D重磁联合反演技术进行计算,从定量角度认识铁矿体深部发育形态、位置与重磁异常之间对应关系,建立钟姑地区白象山铁矿等典型矿床的重磁找矿模式,为该区进一步找矿突破提供地球物理场信息。     

不同饵料种类、投喂方式及环境条件对凡纳滨对虾相对摄食量的影响

为提高对虾养殖过程中的饵料利用率并减少养殖废水的排放,作者以凡纳滨对虾(Litopenaeus vannamei)为实验对象,研究了不同饵料种类、投喂方式、体质量、充气量、光照强度、水温及盐度对其相对摄食量的影响。结果表明:配合饲料组对虾的相对摄食量显著高于冰鲜虾肉组;连续单颗投喂时对虾的相对摄食量较高;相对摄食量随对对虾体重升高而显著(P0.01)下降,而且不同规格的对虾在竞争条件下平均相对摄食量会降低;充气量6 L/min组对虾的相对摄食量明显高于另外两组;弱光环境下对虾的相对摄食量较高;水温和盐度对相对摄食量的影响极显著(P0.01),在32℃时对虾获得最大相对摄食量,在盐度为5时相对摄食量最小,高盐度下组间差异不显著(P0.05)。因此,在实际生产中应采取少量多次的投饵策略,并根据环境条件的变化合理的调整投饵量。     

Livelihood changes and evolution of upland ethnic communities driven by tourism: a case study in Guizhou Province,southwest China

As an effective livelihood approach to alleviate poverty without rural population migration, ethnic tourism has become the primary choice of economic development in ethnic areas worldwide in addition to traditional livelihood approaches. This article applies the theories of livelihood to study the community evolution driven by tourism livelihood and examine three mountainous tourism communities in different stages of tourist area life cycle. Drawing on the methods of GIS spatial analysis, semi-structured interviews and questionnaires, this article proposes a sustainable livelihood framework for ethnic tourism to explore the evolution of ethnic tourism communities by identifying changes in livelihood assets (natural, financial, social, cultural and human capitals) in the process of tourism development. The results show that the development of ethnic tourism has led to changes in the increase of building land, and the diversification of land use functions with a trend of shifting from meeting local villagers' living needs to satisfying tourists, income composition and uneven distribution of tourism income spatially. Ethnic tourism also led to the deterioration of traditional social management structure, collapse of neighboring relationship, the over- commercialization and staged authenticity of ethnic culture, as well as the gradual vanish of agricultural knowledge with a trend of increasing modern business knowledge and higher education. In addition, these changes, involving livelihood assets from natural, economic, human, social and cultural aspects are interrelated and interactive, which form new evolution characters of ethnic community. This study reveals the conflicts over livelihood approaches which have formed new vulnerabilities to impact on sustainable evolution of ethnic communities. This research provides implications for achieving the sustainable development of ethnic communities with the driving force of tourism livelihood.