Research on Ecological Restoration Technology in Arid or Semi-arid Areas from the Perspective of the Belt and Road Initiative     

LI Yue  QI Shi  LI Jingjing 《资源与生态学报(英文版)》2022,13(6):964-976

In the new era of the rapid development of economic globalization and the community of human destiny, the implementation of the ȁc;One Belt and One Road” (OBOR) construction model is designed to coordinate environmental protection and economic development. Most of the countries along the Silk Road in the 21st century are developing countries, and the majority of them are facing the same ecological and developmental difficulties as China. In this paper, under the background of the ȁc;OBOR” strategy and on the basis of the distribution of global climate types, we selected Central Asia and Northwest China, which have temperate continental climates, as the research objects. We sorted out and summarized the main ecological problems faced by Western China and Central Asia during the development of the ȁc;Belt and Road” initiative. At the same time, in combination with the major ecological governance projects implemented in recent years, we proposed key ecological governance technologies that have a certain degree of scalability, such as key technologies for water resource utilization and protection, sand prevention and control, and saline-alkali land governance. The aim was to offer the experiences and a reference for providing technological models for the ȁc;one belt along the road” region and the country to build an effective ecological governance system. Two suggestions are then proposed for improving the feasibility and rationality of ecological governance technology in the construction of the ȁc;One Belt, One Road”. 1) With the implementation of the strategy of ȁc;OBOR” construction, the ecological threats the OBOR countries are facing cannot be ignored. Every country needs to jointly act to build an ȁc;OBOR” ecological civilization. 2) The participants must pay attention to the spatial heterogeneity and temporal dynamics of ecological carrying capacity, and provide data reference and support for the reasonable allocation of ecological governance technology.  相似文献   

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�Ե¾�  ������  ��ǿ  ����� 《大地测量与地球动力学》2014,34(5):21-24

????????λ???????????????????????й???????????GPS/??????????EIGEN-6c2??EGM08?????????????????EIGEN-6c2?????????????EGM08????????2~3 cm??????????????????????????18 cm?????????1985?????????????????(W ₀???????26 cm??  相似文献   

一种 ReliefF 和随机森林模型组合的多波束 海底底质分类方法     

孙健  樊妙  崔晓东  艾波  马丹  阳凡林 《海洋通报》2022,(2)

海底底质的快速探测和精细划分对海洋工程建设 、海洋资源开发等具有重要意义。多波束探测是目前声学底质遥测 的有效手段之一, 通常提取多波束反向散射强度图像和地形数据中的多维特征结合分类器进行底质分类。一方面, 若特征空 间维数过高, 分类效率会显著降低; 另一方面, 个别特征容易放大原始数据处理过程中仍存留的异常现象。针对这一问题, 本文提出了一种结合 Re1iefF 算法和随机森林 (Random Forest, RF) 算法的多波束底质分类方法。提取反向散射强度和地形 共 16 维特征, 利用Re1iefF 算法进行特征筛选, 排除低相关性特征, 降低特征空间维数, 结合采样点数据进行模型训练以构 建多波束底质分类模型。试验结合随机森林算法对未经特征筛选 、经主成分分析 (Principa1 Component Ana1ysis, PCA) 特征 优化后的特征进行分类实验作为对比。本文方法 Kappa 系数达到 85%, 分类总精度高于 90%, 精度具有明显优势, 耗时也 比较短。可见, 本文提出的结合 Re1iefF 和随机森林模型的多波束底质分类方法可以在保证分类精度的同时对多维特征进行 优化, 有效地提高了分类效率, 可对海底底质分类研究提供参考。  相似文献   

基于汶川主震及余震的预警参数与震级相关性研究   总被引：7，自引：0，他引：7       下载免费PDF全文

彭朝勇  杨建思  薛兵  陈阳  朱小毅 《地球物理学报》2013,56(10):3404-3415

地震预警作为一种能够有效减轻地震灾害的手段已经被世界上越来越多的国家和地区所研究,并在实际应用中取得了显著的减灾实效.利用汶川主震及其余震P波和S波初期部分的信息,研究了最终地震震级与4个预警参数的相关性.考察的4个参数是位移幅值(P_d)、速度平方积分(IV2)、P波卓越周期和特征周期(τ_p和τ_c).使用的数据集时间跨度从2008年5月12日至2008年10月4日,共计218次震级大于等于4级的地震事件,包括主震8.0、最大余震6.5和7次大于等于6.0级的事件.P_d、IV2和τ_c在震级小于等于6.5级时与最终震级具有较好的相关性,没有出现震级饱和现象,验证了前人的统计结果.但是在估算主震震级时,都存在不同程度的低估现象,IV2参数尤其明显.另外,P_d和IV2统计曲线在M6级附近存在着一个斜率变化,并且P_d结果与前人统计结果相差较大.τ_p的统计结果表明该参数不适合应用到汶川地区的地震预警系统中.  相似文献   

基于邻域设施的中国大城市网络店铺的区位取向——以上海、深圳、天津、北京四城市为例   总被引：4，自引：0，他引：4  

路紫  李晓楠  杨丽花  杨东  邓丽丽 《地理学报》2011,66(6):813-820

采用一套基于邻域设施的模糊区位取向方法和模糊多属性决策方法,针对中国北京、上海、深圳、天津4 城市淘宝网站6 大商品类别网络店铺的空间集聚情况,通过其所属的完全、重叠、过渡和不完全4 种区位类型,揭示区位取向的倾向性特征和信息时代区位影响因素的变化,并进一步探讨区位取向明显的数码类别商品的网络店铺的最优区位地选择。形成如下认识：①不同商品类别情况下区位取向有很大不同,分散与集聚共同存在。集聚只发生在贵重商品如数码类别商品的网络店铺上,其仍依赖于传统邻域设施;而绝大多数普通商品则相反,几乎不存在重叠区位的布局,已经表现出一种不再遵循传统区位地理论的新的区位取向规律。② 不同商业模式下区位取向不同,c2c 电子商务对其影响更趋向于不同于传统的区位选择,表明c2c 电子商务是网络店铺区位取向影响因素变化的基础。除了旧有的传输网络、货源供给、市场集聚因素外,技术劳动力因素、信任因素渐成主流。③ 利用三角模糊数能计算出基于邻域设施集聚的、区位取向明显的数码类别商品网络店铺的最优区位。选择最优区位是从重叠区位向完全区位过渡的。④ 在电子时代传统的区位理论将得到一定补充或纠正才能全面正确地解释电子服务网点的区位现象。  相似文献   

Removal of Rhodamine B from Water by Benzyl‐Functionalized Ionic Liquids          下载免费PDF全文

Yunchang Fan  Xing Dong  Yun Li  Yingying Zhong  Juan Miao  Shaofeng Hua 《洁净——土壤、空气、水》2016,44(9):1106-1112

  相似文献   

Static vulnerability of an existing r.c. structure and seismic retrofitting by CFRP and base-isolation: A case study     

《Soil Dynamics and Earthquake Engineering》2016

The assessment of the static vulnerability under gravity loads of existing reinforced concrete (r.c.) framed buildings is a serious problem that requires the use of reliable methodologies to evaluate ductile and brittle mechanisms. The present work compares alternative formulations of member chord rotation and section and joint shear strength, proposed by Italian and European seismic codes and guidelines and other expressions available in the scientific literature. To this end, a r.c. framed building built sixty years ago with bi-directional (perimeter) and mono-directional (interior) plane frames, originally designed for five storeys then elevated to six during construction, is studied. A full characterization of the structure and its materials is carried out by means of destructive and non-destructive methods. Then, retrofitting based on the use of both innovative material, such as carbon fibre reinforced polymers (CFRP), and technology, such as base-isolation, are adopted to improve the static and seismic performances of the original structure. Finally, nonlinear analyses are carried out on a three-dimensional fibre model of the original and retrofitted structures, where an elastic linear law idealizes the behaviour of the CFRP up to tension failure and viscoelastic linear and bilinear models are used to idealize the behaviour of the elastomeric and sliding bearings, respectively.  相似文献   

Earthquake magnitude estimation using the τ c and P d method for earthquake early warning systems     

Xing Jin  Hongcai Zhang  Jun Li  Yongxiang Wei  Qiang Ma 《地震科学（英文版）》2013,26(1):23-31

Earthquake early warning (EEW) systems are one of the most effective ways to reduce earthquake disaster. Earthquake magnitude estimation is one of the most important and also the most difficult parts of the entire EEW system. In this paper, based on 142 earthquake events and 253 seismic records that were recorded by the KiK-net in Japan, and aftershocks of the large Wenchuan earthquake in Sichuan, we obtained earthquake magnitude estimation relationships using the τ _c and P _d methods. The standard variances of magnitude calculation of these two formulas are ±0.65 and ±0.56, respectively. The P _d value can also be used to estimate the peak ground motion of velocity, then warning information can be released to the public rapidly, according to the estimation results. In order to insure the stability and reliability of magnitude estimation results, we propose a compatibility test according to the natures of these two parameters. The reliability of the early warning information is significantly improved though this test.  相似文献   

地震预警震级计算方法研究综述   总被引：7，自引：1，他引：6  

张红才  金星  李军  韦永祥  马强 《地球物理学进展》2012,27(2):464-474

地震预警系统是减轻地震灾害的有效手段之一,世界上多个国家和地区都已经建立了地震预警系统,并在实际应用中取得了显著的减灾实效.由于地震预警系统应用中的高度时效性要求,预警震级计算是整个地震预警系统中最重要也是最困难的一部分.本文回顾总结了地震预警研究中采用的一些震级计算方法,并将其归纳为三大类算法:与初始周期相关的算法、与初始幅值相关的算法和与初始强度相关的算法.对每种算法都做了详尽介绍和仔细分析,同时列举出与该算法相关的研究成果.通过对这些算法的分析总结并结合我国地震观测台网的实际情况,作者推荐τc、Pd两种方法作为我国地震预警系统建设中优先采用的两种预警震级算法.  相似文献   

Contributions of slab fluid and sediment melt components to magmatism in the Mariana Arc–Trough system: Evidence from geochemical compositions and Sr,Nd, and noble gas isotope systematics          下载免费PDF全文

Yasuo Ikeda  Keisuke Nagao  Teruaki Ishii  Daisuke Matsumoto  Robert J. Stern  Hiroo Kagami  Makoto Arima  Sherman H. Bloomer 《Island Arc》2016,25(4):253-273

This study presents new major and trace element, mineral, and Sr, Nd, and noble gas isotope geochemical analyses of basalts, gabbro, and clinopyroxenite from the Mariana Arc (Central Islands and Southern Seamount provinces) including the forearc, and the Mariana Trough (Central Graben and Spreading Ridge). Mantle source compositions beneath the Mariana Arc and the Mariana Trough indicate a mantle source that is depleted in high field strength elements relative to MORB (mid‐oceanic ridge basalt). Samples from the Mariana Arc, characterized by high ratios of Ba/Th, U/Th, ⁸⁴Kr/⁴He and ¹³²Xe/⁴He, are explained by addition of fluid from the subducted slab to the mantle wedge. Correlations of noble gas data, as well as large ion lithophile elements, indicate that heavy noble gases (Ar, Kr, and Xe) provide evidence for fluid fluxing into the mantle wedge. On the other hand, major elements and Sr, Nd, He, and Ne isotopic data of basalts from the Mariana Trough are geochemically indistinguishable from MORB. Correlations of ³He/⁴He and ⁴⁰Ar/³⁶Ar in the Mariana Trough samples are explained by mixing between MORB and atmosphere. One sample from the Central Graben indicates extreme enrichment in ²⁰Ne/²²Ne and ²¹Ne/²²Ne, suggesting incorporation of solar‐type Ne in the magma source. Excess ¹²⁹Xe is also observed in this sample suggesting primordial noble gases in the mantle source. The Mariana Trough basalts indicate that both fluid and sediment components contributed to the basalts, with slab‐derived fluids dominating beneath the Spreading Ridge, and that sediment melts, characterized by high La/Sm and relatively low U/Th and Zr/Nb, dominate in the source region of basalts from the Central Graben.  相似文献