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321.
基于图式语言的少数民族传统村落空间布局特征研究   总被引:1,自引:0,他引:1  
李伯华  徐崇丽  郑始年  王莎  窦银娣 《地理科学》2020,40(11):1784-1794
选取芋头村、皇都村、高上村及坪坦村4个典型侗族传统村落,以探究不同区域间图式语言的空间嵌套为目的,对侗族传统村落空间布局特征进行分析和总结。研究显示:① 不同侗族传统村落图式语汇类型多样,但互相之间存在共通性。通过对坪坦村进行图式语言空间嵌套,验证了侗族传统村落空间布局图式语言体系的有效性和普适性。② 侗族传统村落始终坚持“顺其自然,因地制宜”的基本理念有序发展,多呈现“水域空间–居住空间–连接空间–公共空间”的空间序列。③ 侗族传统村落整体上表现为以公共建筑为核心,周围建筑呈向心内聚式分布的特点。④ 侗族传统村落发展扩张中始终遵循本土性和秩序性的语法原则,空间要素的设计和布局多以传统风水观为指导。⑤ 传统村落空间布局图式语言体系对于同类型村落的空间修复与更新具有积极作用,其语汇、句法及语法的空间普适性有利于实现传统村落景观风貌的有效保护和可持续发展。  相似文献   
322.
在新修订的课程标准中,地理学科传统的三维目标逐步转向为由地理实践力、人地协调观、区域认知和综合思维所组成的核心素养四维目标。文章基于杭州市西湖区寻山路径标识系统和公共厕所布局合理性调查综合性实践活动,采用半自主考察模式,开展了高一年级地理实践力的培育和挖掘研究,并进一步对本阶段学生的地理学科能力进行了测度。  相似文献   
323.
Artificial earthquake catalogue simulation is one of the ways to effectively improve the incompleteness of the existing earthquake catalogue,the scarcity of large earthquake records and the improvement of seismological research.Based on the Poisson distribution model of seismic activity and the Gutenberg-Richter magnitude-frequency relationship, the Monte Carlo method which can describe the characteristics of the stochastic nature and the physical experiment process is used.This paper simulates the future seismic catalogues of the Fenhe-Weihe seismic belt of different durations and conducts statistical tests on them. The analysis shows that the simulation catalogue meets the set seismic activity parameters and meets the Poisson distribution hypothesis,which can obtain a better simulated earthquake catalogues that meets the seismic activity characteristics.According to the simulated earthquake catalogues,future earthquake trends in this region are analyzed to provide reference for seismic hazard analysis.  相似文献   
324.
The aim of this study is to promote appropriate land development policies and to improve operations of flood risk in urban areas. This study first illustrated a multi-parameter flood hazard index (FHI) model for assessing potential flood risk areas in the Guanzhong Urban Area (GUA), a large-scale urban area in northwestern China. The FHI model consisted of the following seven parameters: rainfall intensity, flow accumulation, distance from the river network, elevation, land use, surface slope, and geology. The parameter weights were assigned using an analytical hierarchy process and the sum weight of the first three parameters accounted for 71.21% of the total weight and had significant influence on flooding. By combining with population factor, the FHI model was modified to estimate the flood control area in the GUA. The spatial distribution of the flood risk was obviously different in the flood hazard area and flood control area. The very low risk and medium risk area in the flood control area increased by 11.19% and reduced by 9.03% compared to flood hazard area, but there were no obvious differences in other levels of risk areas. The flood control assessment indicated that very high flood risk areas were principally concentrated along river banks (the Weihe River and its tributaries) and in the middle of the Guanzhong Plain. Land use and population distribution are related to flooding. Especially, forestland was located in 84.48% of the very low risk area, while low risk areas were mainly located in 91.49% of high population dispersion area.  相似文献   
325.
为了解青海湖浮游植物群落结构特征、时空分布格局及其关键环境驱动因子,于2020年5月(春)、8月(夏)、10月(秋)对青海湖进行系统调查,分析浮游植物群落在3个季度和4个区域(湖滨带、进水区、浅水区和深水区)间的差异。3次调查共检出浮游植物6门39属65种,物种组成以硅藻(36种,占总物种数的55.38%)、绿藻(17种,26.15%)和蓝藻(7种,10.76%)为主。4个区域间的浮游植物丰度存在显著差别,其中深水区丰度显著高于其他区域,主要原因可能在于深水区的环境较为稳定。3个季节间,浮游植物丰度和生物量具有较大差异:夏季和秋季的丰度、生物量均为春季的近10倍;浮游植物的优势类群和种类也发生了较大的变化:春季最具优势类群为硅藻门,优势种也主要隶属于硅藻门,而夏、秋两季则以蓝藻门种属占据主要优势。春季浮游植物的Pielou均匀度和Simpson多样性指数显著高于夏、秋两季,秋季Margalef指数和Shannon-Wiener多样性指数高于夏季。PERMANOVA分析和NMDS分析显示,青海湖浮游植物群落结构在不同区域和不同季节间具有显著差异。此外,dbRDA分析表明:盐度、水温和总磷...  相似文献   
326.
Chakrabortty  Rabin  Pal  Subodh Chandra  Sahana  Mehebub  Mondal  Ayan  Dou  Jie  Pham  Binh Thai  Yunus  Ali P. 《Natural Hazards》2020,104(2):1259-1294
Natural Hazards - Land degradation is very severe in the subtropical monsoon-dominated region due to the uncertainty of rainfall in the long term, and most of the rainfall occurs with high...  相似文献   
327.
A wide variety of near-fault strong ground motion records were collected from various tectonic environments worldwide and were used to study the peak value ratio and response spectrum ratio of the vertical to horizontal component of ground motion, focusing on the effect of earthquake magnitude, site conditions, pulse duration, and statistical component. The results show that both the peak value ratio and response spectrum ratio are larger than the 2/3 value prescribed in existing seismic codes, and the relationship between the vertical and horizontal ground motions is comparatively intricate. In addition, the effect of the near-fault ground motions on bridge performance is analyzed, considering both the material nonlinear characteristics and the P~? effect.  相似文献   
328.
针对舰船轴频电场信号源的发生机理和应用研究的问题,以实验室轴电流模拟装置为平台, 建立了一种基于等效电路的舰船轴频电流的模型,研究了轴电流模拟装置的大轴振动情况,对大轴电流进行了建模仿真,得到了不同转速下大轴轴电流波形图及其频谱,使用轴电流模拟装置进行了轴电流实验。 通过仿真结果与轴电流实验数据对比,计算得到该建模方法轴电流平均误差在 8% 以内,验证了该建模方法在理论上的可行性。  相似文献   
329.
Aquifer hydraulic parameters are commonly inferred from constant-rate pumping tests, while variable pumping rates are frequently encountered in actual field conditions. In this study, we propose a generally applicable dimensionless form of the analytical solution for variable-rate pumping tests in confined aquifers. In particular, we adopt a piecewise-linear fitting of variable pumping rates and propose a new type-curve method for estimating the hydraulic conductivity (K ) and specific storage (Ss ) of the investigated confined aquifer. For each test, a series of type curves, which depend on the variable pumping rates, the location of observation wells and the introduced first dimensionless inflection time, need to be provided for matching the observed drawdown data on a log-log graph. We first demonstrate the applicability and robustness of this method through a synthetic pumping test. Subsequently, we apply this method to analyze drawdown data from four pumping tests conducted within a multilayered aquifer/aquitard system in Wuxi city, Jiangsu Province, China. The parameter estimates are then compared with those reported by PEST. The K and Ss values estimated by the new type-curve method are found to be quite close to PEST-based estimates. Parameter estimation results demonstrate the difference in K and Ss values between observation wells. The difference could be attributed to the spatial heterogeneity in K and Ss . A future research topic may focus on the characterization of K and Ss heterogeneity with the currently available drawdown data from variable-rate pumping tests.  相似文献   
330.
Arctic sea ice area and thickness have declined dramatically during the recent decades. Sea ice physical and mechanical properties become increasingly important. Traditional methods of studying ice mechanical parameters such as ice-coring cannot realize field test and long-term observation. A new principle of measuring mechanical properties of ice using ultrasonic was studied and an ultrasonic system was proposed to achieve automatic observation of ice mechanical parameters (Young’s modulus, shear modulus and bulk modulus). The ultrasonic system can measure the ultrasonic velocity through ice at different temperature, salinity and density of ice. When ambient temperature decreased from 0°C to ?30°C, ultrasonic velocity and mechanical properties of ice increased, and vice versa. The shear modulus of the freshwater ice and sea ice varied from 2.098 GPa to 2.48 GPa and 2.927 GPa to 4.374 GPa, respectively. The bulk modulus of freshwater ice remained between 3.074 GPa and 4.566 GPa and the sea ice bulk modulus varied from 1.211 GPa to 3.089 GPa. The freshwater ice Young’s modulus kept between 5.156 GPa and 6.264 GPa and sea ice Young’s modulus varied from 3.793 GPa to 7.492 GPa. The results of ultrasonic measurement are consistent with previous studies and there is a consistent trend of mechanical modulus of ice between the process of ice temperature rising and falling. Finally, this ultrasonic method and the ultrasonic system will help to achieve the long-term observation of ice mechanical properties of ice and improve accuracy of sea ice models.  相似文献   
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