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Progress and implications of international rural space research 国际农村空间研究的进展和影响
Pub Date : 2021-09-30 DOI: 10.18306/dlkxjz.2019.12.014
Dan Wang, Zuyun Liu
Space is a product of society. Driven by industrialization, urbanization, informatization and government policies, China’s rural space is undergoing drastic reconstruction. As one of the core contents of international rural geography research, rural space research are multi-disciplinary, multi perspective, multi-dimensional and multi-method, forming a rich research field. In order to comprehensively grasp the progress of rural space research abroad, this study reviewed international rural space research literature in recent 40 years. The study found that foreign scholars described the connotation of rural space from the aspects of material, imagination and practice, emphasize the importance of daily life practice. It introduced living space to construct a more systematic research framework of rural space by establishing a “three-fold model of rural space”. With regard to the theoretical perspective, international research on rural space has experienced three stages: functionalism, political economics and social constructivism. In the evolution of time, it has realized the transformation from productivism to post-productivism; in the spatial dimension, it realizes the multiple superposition of settlement space, economic space, social space and cultural space. As a whole, international research on rural space has realized the transformation from material level to social representation, from objective space to subjective space, and from static one-dimensional space to dynamic multi-dimensional space, which enlightens us on the importance of interdisciplinary research and “social cultural” research on rural space. The construction of rural space in China needs to pay attention to the subject status of farmers and multifunction of rural space, respect the role of locality and difference of various places, and recover the function of production of meaning of rural space.
空间是社会的产物。在工业化、城镇化、信息化和政府政策的推动下,中国的乡村空间正在经历剧烈的重构。作为国际乡村地理学研究的核心内容之一,乡村空间研究多学科、多视角、多维度、多方法,形成了丰富的研究领域。为了全面把握国外乡村空间研究进展,本研究对近40年来国际乡村空间研究文献进行了综述。研究发现,国外学者从物质、想象和实践三个方面描述乡村空间的内涵,强调日常生活实践的重要性。通过建立“乡村空间三重模型”,引入生活空间,构建更为系统的乡村空间研究框架。从理论角度看,国际上对乡村空间的研究经历了功能主义、政治经济学和社会建构主义三个阶段。在时间的演进中,它实现了从生产主义到后生产主义的转变;在空间维度上,实现了聚落空间、经济空间、社会空间、文化空间的多重叠加。从整体上看,国际上对乡村空间的研究已经实现了从物质层面到社会表征层面、从客观空间到主观空间、从静态一维空间到动态多维空间的转变,这就启示了乡村空间跨学科研究和“社会文化”研究的重要性。中国乡村空间的建设需要关注农民的主体地位和乡村空间的多功能,尊重地方的作用和各地的差异,恢复乡村空间的意义生产功能。
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引用次数: 4
Population distribution characteristics and its relationship with natural factors in karst mountainous areas of Northwest Guangxi 桂西北喀斯特山区人口分布特征及其与自然因素的关系
Pub Date : 2021-09-30 DOI: 10.24294/jgc.v3i1.1303
S. Shi, Bingkang Xie, Baoqing Hu, Chuanyong Tang, Yan Yan, Xiaoqing Li
The smallest administrative unit of the sixth national census-township (town) is selected as the basic unit, the population spatial distribution characteristics at the township (town) level in karst mountainous areas of northwest Guangxi are analyzed by using Lorenz curve and spatial correlation analysis method, and the influence intensity of natural factors on regional population spatial distribution is detected by using geographic detector method. The results show that: 1. the spatial distribution of population at the township (town) level has the characteristics of imbalance, showing generally significant positive correlation and certain aggregation; 2. there are significant differences in the impact of the spatial distribution of various natural factors on the population distribution. For the towns without karst distribution in the northwest and central south of the study area, the population density increases with the increase of factors conducive to human residence, but the average population density is only 79 people / km2. In the towns with karst distribution in the East and south, the spatial distribution of population density and natural factors is not a simple increase or decrease relationship, but fluctuates with the change of karst distribution area. 3. The factor detection results of the geographic detector show that the altitude has the greatest impact on the spatial distribution of population. The interactive detection results show that the impact intensity of any two natural factors after superposition and interaction presents nonlinear enhancement and two factor enhancement. It can be seen that the karst mountain area in northwest Guangxi is similar to other areas. Altitude is one of the main factors affecting the spatial distribution of population, but the river network density and unique geological landform of karst mountain area have a strong catalytic effect on the spatial distribution of population. The superposition and interaction with other factors can further strengthen the impact on population distribution.
以第六次全国人口普查最小的行政单位乡(镇)为基本单位,利用Lorenz曲线和空间相关分析法分析桂西北喀斯特山区乡(镇)级人口空间分布特征,利用地理探测器法检测自然因素对区域人口空间分布的影响强度。结果表明:1。乡(镇)级人口空间分布具有不平衡特征,总体上表现为显著的正相关和一定的聚集性;2. 各自然因子的空间分布对人口分布的影响存在显著差异。研究区西北部和中南部无岩溶分布的城镇,人口密度随适宜人居因素的增加而增加,但平均人口密度仅为79人/ km2。在东部和南部喀斯特分布城镇,人口密度的空间分布与自然因素不是简单的增减关系,而是随着喀斯特分布面积的变化而波动。3.地理探测器的因子检测结果表明,海拔对人口空间分布的影响最大。交互检测结果表明,任意两个自然因子叠加交互后的冲击强度呈现非线性增强和双因子增强。可以看出,桂西北喀斯特山区与其他地区相似。海拔高度是影响人口空间分布的主要因素之一,但喀斯特山区的河网密度和独特的地质地貌对人口空间分布具有较强的催化作用。与其他因素的叠加和相互作用可以进一步加强对人口分布的影响。
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引用次数: 0
A review of the research on externality of urban network 城市网络外部性研究述评
Pub Date : 2021-09-30 DOI: 10.24294/jgc.v4i1.1314
Yuhong Cheng, Xiaomin Su
Urban network research has become the frontier academic field of international urban research and has gradually become a hot spot. At present, the related literature on “urban network” mostly focuses on conceptual discussion, dimension analysis, and network structure analysis. Research on the influence of network on regional economic development is relatively weak. Externality, as an essential attribute of urban network, is of great significance to the evolution of urban network and the development of cities and regions. This article starts from a comparison of agglomeration externalities with urban network externalities, focusing on the review and evaluation of the formation mechanism, utility, and measurement methods of urban network externalities.The synergy effect, integration effect, and borrowing size are considered important reasons for the formation of urban network externalities. The research on the effectiveness of urban network externalities focuses on two aspects. The first is the role of factor mobility in promoting knowledge diffusion and innovation, and the second is the impact of urban network on competitiveness and economic growth. Based on the existing literatures, the research on the measurement of urban network externalities mainly involves identification and estimation, including three common methods as correlation analysis, regression analysis, and spatial econometric analysis. The existing empirical researches on externalities are still mostly based on static analysis and lack dynamic consideration. The issues that need further attention in the future include theoretical understanding of urban network externalities, externality measurement methods, and empirical research.
城市网络研究已成为国际城市研究的前沿学术领域,并逐渐成为热点。目前,关于“城市网络”的相关文献多集中在概念讨论、维度分析、网络结构分析等方面。网络对区域经济发展影响的研究相对薄弱。外部性作为城市网络的本质属性,对城市网络的演化和城市与区域的发展具有重要意义。本文从城市群外部性与城市网络外部性的比较入手,重点对城市网络外部性的形成机制、效用和测度方法进行了回顾和评价。协同效应、整合效应和借贷规模被认为是城市网络外部性形成的重要原因。对城市网络外部性有效性的研究主要集中在两个方面。首先是要素流动对知识扩散和创新的促进作用,其次是城市网络对竞争力和经济增长的影响。在现有文献的基础上,对城市网络外部性测度的研究主要涉及识别和估计,常用的方法有相关分析、回归分析和空间计量分析三种。现有的外部性实证研究大多基于静态分析,缺乏动态考虑。未来需要进一步关注的问题包括对城市网络外部性的理论认识、外部性度量方法和实证研究。
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引用次数: 0
Study on the distribution pattern and influencing factors of shrinking cities in Northeast China based on the random forest model 基于随机森林模型的东北萎缩城市分布格局及影响因素研究
Pub Date : 2021-09-30 DOI: 10.24294/jgc.v3i1.1305
Guanghua Yan, Xi Chen, Yun Zhang
Based on the population change data of 2005-2009, 2010-2014, 2015-2019 and 2005-2019, the shrinking cities in Northeast China are determined to analyze their spatial distribution pattern. And the influencing factors and effects of Shrinking Cities in Northeast China are explored by using multiple linear regression method and random forest regression method. The results show that: 1) In space, the shrinking cities in Northeast China are mainly distributed in the “land edge” areas represented by Changbai Mountain, Sanjiang Plain, Xiaoxing’an Mountain and Daxing’an Mountain. In terms of time, the contraction center shows an obvious trend of moving northward, while the opposite expansion center shows a trend of moving southward, and the Shrinking Cities gather further; 2) in the study of influencing factors, the results of multiple linear regression and random forest regression show that socio-economic factors play a major role in the formation of shrinking cities; 3) the precision of random forest regression is higher than that of multiple linear regression. The results show that per capita GDP has the greatest impact on the contraction intensity, followed by the unemployment rate, science and education expenses and the average wage of on-the-job workers. Among the four influencing factors, only the unemployment rate promotes the contraction, and the other three influencing factors inhibit the formation of shrinking cities to various degrees.
基于2005-2009年、2010-2014年、2015-2019年和2005-2019年的人口变化数据,确定东北萎缩城市的空间分布格局。运用多元线性回归和随机森林回归方法,探讨了东北地区城市收缩的影响因素和效应。结果表明:①空间上,东北萎缩城市主要分布在以长白山、三江平原、小兴安岭和大兴安岭为代表的“陆缘”地区;从时间上看,收缩中心呈明显的北移趋势,相反的扩张中心呈南移趋势,收缩城市进一步集聚;2)在影响因素研究中,多元线性回归和随机森林回归结果表明,社会经济因素在城市萎缩形成中起主要作用;3)随机森林回归的精度高于多元线性回归。结果表明,人均GDP对收缩强度的影响最大,其次是失业率、科教费用和在岗职工平均工资。在四个影响因素中,只有失业率对收缩有促进作用,其他三个影响因素对收缩城市的形成都有不同程度的抑制作用。
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引用次数: 0
A Modified Range Migration Algorithm for FMCW SAR Signal Processing 一种改进的FMCW SAR信号处理距离偏移算法
Pub Date : 2021-09-30 DOI: 10.24294/jgc.v4i1.1312
Yake Li, S. O'Young
The range migration algorithm (RMA) is an accurate imaging method for processing synthetic aperture radar (SAR) signals. However, this algorithm requires a big amount of computation when performing Stolt mapping. In high squint and wide beamwidth imaging, this operation also requires big memory size to store the result spectrum after Stolt mapping because the spectrum will be significantly expanded. A modified Stolt mapping that does not expand the signal spectrum while still maintains the processing accuracy is proposed in this paper to improve the efficiency of the RMA when processing frequency modulated continuous wave (FMCW) SAR signals. The modified RMA has roughly the same computational load and required the same memory size as the range Doppler algorithm (RDA) when processing FMCW SAR data. In extreme cases when the original spectrum is significantly modified by the Stolt mapping, the modified RMA achieves better focusing quality than the traditional RMA. Simulation and real data is used to verify the performance of the proposed RMA.
距离偏移算法(RMA)是处理合成孔径雷达(SAR)信号的一种精确成像方法。然而,该算法在执行Stolt映射时需要大量的计算量。在高斜视和宽波束宽度成像中,由于Stolt映射后的光谱将显著扩展,因此该操作还需要较大的内存来存储结果光谱。为了提高RMA处理调频连续波(FMCW) SAR信号的效率,本文提出了一种不扩大信号频谱同时保持处理精度的改进Stolt映射方法。在处理FMCW SAR数据时,改进的RMA与距离多普勒算法(RDA)具有大致相同的计算负荷和相同的内存大小。在原始频谱被Stolt映射显著修改的极端情况下,改进的RMA比传统的RMA具有更好的聚焦质量。通过仿真和实际数据验证了该算法的性能。
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引用次数: 0
Analysis of ecological security pattern of rare earth mining areas in South China based on MCR model 基于MCR模型的华南稀土矿区生态安全格局分析
Pub Date : 2021-09-30 DOI: 10.24294/jgc.v3i1.1304
Hengkai Li, Yuting Liu, Qin Li, Xiuli Wang
The rare earth mining area in South China is the main production base of ionic rare earth in the world, which has brought inestimable economic value to the local area and even the whole nation. However, due to the lack of mining technology and excessive pursuit for economic profits, a series of environmental problems have arisen, which is a great threat to the ecosystem of the mining area. Taking Lingbei rare earth mining area in Ganzhou as an example, this paper discriminated and analyzed such aspects as the ecological source, ecological corridor and ecological nodes of the mining area based on the landscape ecological security pattern theory and the minimum cumulative resistance model (MCR) method, and constructed a landscape ecological security pattern of the mining area during the 2009, 2013 and 2018. The results show that: i) The patch area of the ecological source of rare earth mining area is small, mainly concentrated in the east and west sides of the mining area. ii) During the selected year, the ecological source area, ecological corridors, radiation channels and the number of ecological nodes in the rare earth mining area are increasing, indicating that the landscape ecological security of the rare earth mining area has been improved to some extent, but it remains necessary for relevant departments to make a optimized planning to further reconstruct the ecological security pattern of the rare earth mining area.
华南稀土矿区是世界离子稀土的主要生产基地,为当地乃至全国带来了不可估量的经济价值。然而,由于采矿技术的缺乏和对经济利益的过度追求,产生了一系列的环境问题,对矿区的生态系统构成了极大的威胁。以赣州灵北稀土矿区为例,基于景观生态安全格局理论和最小累积阻力模型(MCR)方法,对矿区生态源、生态廊道、生态节点等方面进行了判别分析,构建了矿区2009年、2013年和2018年的景观生态安全格局。结果表明:①稀土矿区生态源斑块面积较小,主要集中在矿区东、西两侧;(2)在所选年份,稀土矿区生态源面积、生态廊道、辐射通道、生态节点数量均有所增加,表明稀土矿区景观生态安全得到了一定程度的改善,但仍需相关部门进行优化规划,进一步重构稀土矿区生态安全格局。
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引用次数: 1
Order, scale structure and coupling types of coastal port city system from the perspective of multi-function 多功能视角下的沿海港口城市体系秩序、规模结构与耦合类型
Pub Date : 2021-09-29 DOI: 10.24294/jgc.v3i1.1302
Jianke Guo, Lulu Wu, B. Li, Yafeng Qin
Using the rank scale rule, taking 47 major port cities in China from 2001 to 2015 as research samples, this paper discusses the rank scale characteristics and hierarchical structure of coastal port city system from a multi-functional perspective, and divides the coupling type of multi-functional development based on shipping logistics. The research shows that: 1) from 2001 to 2015, the scale-free area of manufacturing function order scale distribution in the coastal port city system appeared bifractal structure, the hierarchical segmentation characteristics appeared, and the other functions were single fractal; From the perspective of long-term evolution, only the order and scale distribution of shipping logistics function has developed from centralization to equilibrium, while the business function, manufacturing function (scale-free region I), modern service function and population distribution function are in a centralized situation. 2) The hierarchical structure of coastal port city system has gradually changed from pyramid structure to spindle structure, and generally formed five levels: national hub, regional hub, regional sub center, regional node and local node. 3) From the perspective of multi-functional coupling types, the traditional functions of port cities are generally ahead, while the high-end service functions lag behind, and the improvement speed of urban functions is slow and tends to be flat, indicating that the multi-functional development of China’s coastal port cities is still at a low level, and the industrial system structure needs to be further optimized. 4) From the perspective of port cities at different levels, the functions of regional hub cities and regional sub central cities are in the stage of rapid growth; regional and local node cities are still in the growth stage of traditional functions such as industry and commerce.
运用等级尺度法则,以2001 - 2015年中国47个主要港口城市为研究样本,从多功能视角探讨了沿海港口城市体系的等级尺度特征和层次结构,并划分了基于航运物流的多功能发展耦合类型。研究表明:1)2001 - 2015年,沿海港口城市系统制造业功能无标度区有序尺度分布呈现分形结构,呈现分层分割特征,其他功能呈现单一分形特征;从长期演化的角度看,只有航运物流功能的顺序和规模分布由集中向均衡发展,而商务功能、制造功能(无标度区I)、现代服务功能和人口分布功能则处于集中状态。②沿海港口城市体系层次结构由金字塔结构逐渐向主轴结构转变,总体上形成了国家枢纽、区域枢纽、区域副中心、区域节点和地方节点五个层次。3)从多功能耦合类型来看,港口城市传统功能总体领先,高端服务功能滞后,城市功能提升速度缓慢且趋于平缓,说明中国沿海港口城市多功能发展仍处于较低水平,产业体系结构有待进一步优化。(4)从不同层次的港口城市来看,区域枢纽城市和区域副中心城市的功能均处于快速增长阶段;区域和地方节点城市仍处于工业、商业等传统功能的成长阶段。
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引用次数: 0
Genesis of Langrial Iron Ore of Hazara area, Khyber Pakhtunkhwa, Pakistan 巴基斯坦开伯尔-普赫图赫瓦省哈扎拉地区Langrial铁矿石的成因
Pub Date : 2021-09-06 DOI: 10.24294/JGC.V4I2.740
Naghma Haider, Sajjad Khan, R. H. Siddiqui, S. Iqbal, Nazar-Ul Haq
In this paper, a detailed mineralogical and genesis investigation have been carried out in the seven locations of the Iron Ore in Hazara area. Thick bedded iron ore have been observed between Kawagarh Formation and Hangu Formation i.e, Cretaceous-Paleocene boundary. At the base of Hangu Formation, variable thickness of these lateritic beds spread throughout the Hazara and Kohat-Potwar plateau. This hematite ore exists in the form of unconformity. X-ray diffraction technique (XRD), X-ray fluorescence spectrometry (XRF), detailed petroghraphic study and scanning electron microscope (SEM) techniques indicated that those iron bears minerals including hematite, chamosite and quartz, albite, clinochlore, illite-montmorillonite, kaolinite, calcite, dolomite, whereas ankerite are the impurities present in these beds. The X-ray fluorescence (XRF) results show that the total Fe2O3 ranges from 39 to 56%, with high silica and alumina ratio of less than one. Beneficiation requires for significant increase in ore grade. The petroghraphic study revealed the presence of ooids fragments as nuclei of other ooids with limited clastic supply, which indicate high energy shallow marine depositional setting under warm and humid climate. The overall results show that Langrial Iron Ore is a low-grade iron ore which can be upgraded up to 62% by applying modern mining techniques so as to fulfill steel requirements of the country.
本文对哈扎拉地区铁矿的7个地点进行了详细的矿物学和成因调查。在卡瓦格尔组与汉谷组之间,即白垩纪—古新世界线上,发现了厚层状铁矿。在汉古组底部,这些厚度不同的红土层遍布哈扎拉和科哈特-波特瓦尔高原。该赤铁矿以不整合形态存在。x射线衍射技术(XRD)、x射线荧光光谱(XRF)、详细的岩石学研究和扫描电镜(SEM)技术表明,这些含铁矿物包括赤铁矿、辉钼矿和石英、钠长石、斜长石、伊利蒙脱石、高岭石、方解石、白云石,而铁白云石是这些矿床中的杂质。x射线荧光(XRF)结果表明,Fe2O3总量在39 ~ 56%之间,高硅铝比小于1。选矿需要大幅度提高矿石品位。岩石学研究表明,该地区的碎屑颗粒为其他碎屑颗粒的核,碎屑供应有限,表明该区处于温暖湿润气候下的高能浅海沉积环境。综合分析结果表明,兰格里亚尔铁矿属低品位铁矿,采用现代采矿技术可将品位提升至62%以上,满足国家钢铁需求。
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引用次数: 0
Research progress and prospect of coastal flood disaster risk assessment against global climate change 全球气候变化背景下沿海洪涝灾害风险评估研究进展与展望
Pub Date : 2021-09-04 DOI: 10.24294/jgc.v4i2.1311
Jiayi Fang, P. Shi
The sea level rise under global climate change and coastal floods caused by extreme sea levels due to the high tide levels and storm surges have huge impacts on coastal society, economy, and natural environment. It has drawn great attention from global scientific researchers. This study examines the definitions and elements of coastal flooding in the general and narrow senses, and mainly focuses on the components of coastal flooding in the narrow sense. Based on the natural disaster system theory, the review systematically summarizes the progress of coastal flood research in China, and then discusses existing problems in present studies and provide future research directions with regard to this issue. It is proposed that future studies need to strengthen research on adapting to climate change in coastal areas, including studies on the risk of multi- hazards and uncertainties of hazard impacts under climate change, risk assessment of key exposure (critical infrastructure) in coastal hotspots, and cost-benefit analysis of adaptation and mitigation measures in coastal areas. Efforts to improve the resilience of coastal areas under climate change should be given more attention. The research community also should establish the mechanism of data sharing among disciplines to meet the needs of future risk assessments, so that coastal issues can be more comprehensively, systematically, and dynamically studied.
全球气候变化下的海平面上升以及因涨潮和风暴潮导致的极端海平面引发的沿海洪水对沿海社会、经济和自然环境产生了巨大的影响。它引起了全球科研人员的高度关注。本文从广义和狭义两方面考察了海岸洪水的定义和构成要素,并重点研究了狭义海岸洪水的构成要素。本文以自然灾害系统理论为基础,系统总结了中国沿海洪水研究的进展,探讨了目前研究中存在的问题,并提出了未来的研究方向。未来的研究需要加强沿海地区适应气候变化的研究,包括气候变化下的多灾害风险和灾害影响的不确定性研究、沿海热点地区关键暴露点(关键基础设施)风险评估、沿海地区适应和减缓措施的成本效益分析等。应该更加重视提高沿海地区在气候变化下的适应能力。研究界还应建立学科间的数据共享机制,以满足未来风险评估的需要,从而更加全面、系统、动态地研究沿海问题。
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引用次数: 1
Study the bio-potential parameter for the detection of seismic and environmental changes in Indian region 研究生物电位参数在印度地区地震和环境变化探测中的应用
Pub Date : 2021-08-01 DOI: 10.24294/jgc.v4i2.765
R. Tiwari, Vijay S. Katta, Vinod Kushwah, M. Gaur, P. Dimri
The changes the magnetic flux generated (electric, magnetic and electromagnetic waves) on the surface of earth due to sudden changes is a matter of discussion. These emissions occur along the fault line generated due to geological and tectonic processes. When sudden changes occur in the environment due to seismic and atmospheric variations, these sensing was observed by creatures and human bodies because the animals and trees adopt the abnormal signals and change the behavior. We have analyzed the changing behavior of recorded signal by live sensors (i.e., banyan tree). So we use the deep-rooted and long-aged banyan tree. The root of banyan tree (long-aged) has been working as a live sensor to record the geological and environmental changes. We record the low frequency signals propagated through solar-terrestrial environment which directly affect the root system of the banyan tree and changes that have been observed by live sensors. Then, very low frequency (VLF) signal may propagate to the earth-ionosphere waveguide. We have also analyzed the different parameters of live cells which is inbuilt in latex of the tree, so we record the dielectric parameters of green stem latex and found some parameters i.e., dielectric constant (ε) and dielectric loss (ε’) of various trees to verify these natural hazards and found good correlation. Therefore, we can say by regularly monitoring the bio-potential signal and dielectric properties of banyan tree and we are able to find the precursory signature of seismic hazards and environmental changes.
地球表面由于突然变化而产生的磁通量(电磁波、电磁波和电磁波)的变化是一个讨论的问题。这些排放物沿着由地质和构造过程产生的断层线发生。当环境因地震和大气变化而发生突然变化时,这些感知被动物和人体观察到,因为动物和树木接受了异常信号并改变了行为。我们分析了实时传感器(即榕树)记录的信号的变化行为。所以我们选用了树根深、树龄长的榕树。榕树的树根作为一个实时传感器,记录着地质和环境的变化。我们记录了通过日地环境传播的直接影响榕树根系的低频信号和实时传感器观测到的变化。然后,甚低频(VLF)信号可以传播到地球电离层波导中。我们还分析了绿茎胶乳内嵌的活细胞的不同参数,记录了绿茎胶乳的介电参数,得到了不同树种的介电常数(ε)和介电损耗(ε’)等参数来验证这些自然危害,并发现了良好的相关性。因此,我们可以说,通过定期监测榕树的生物电位信号和介电特性,可以发现地震灾害和环境变化的前兆特征。
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引用次数: 1
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