新丰江水库地震监测系统介绍     

刘少文  李敬  刘志华  赖细华 《华南地震》2012,(Z1):103-109

新丰江水库区的地震监测系统是随着新丰江水库的建立而发展起来的,在1960年建设了双下第一个地震观测台站,逐步完善新丰江水库的地震监测系统,经历了从人工值守、模拟遥测、数字化遥测的地震监测模式,为新丰江水库地震研究积累了大量的观测资料。  相似文献   

成矿元素集中或分散程度的理想化研讨   总被引：1，自引：1，他引：0       下载免费PDF全文

徐锡华 《地质找矿论丛》1999,14(2):1-7,62

本文在理想化的假定条件下,借助于热力学与信息学的基本概念和原理,讨论并推导出元素浓集克拉克值Ｋ分别与热力学概率Ω、热力学熵Ｓ以及信息量Ｉ的非线性关系表达式;引用并探讨了元素浓集克拉克值Ｋ与成矿能耗Ｅ之间的关系。本文在一定程度上将有益对成矿作用的研究乃至成矿信息定量模型的建立与应用。  相似文献   

Sediment load change with erosion processes under simulated rainfall events     

Sun  Liying  Fang  Haiyan  Cai  Qiangguo  Yang  Xihua  He  Jijun  Zhou  John L.  Wang  Xunming 《地理学报(英文版)》2019,29(6):1001-1020

Journal of Geographical Sciences - It is of great significance to quantify sediment load changing with erosion processes for improving the precision of soil loss prediction. Indoor rainfall...  相似文献   

Application and comparison of two symptom-based eutrophication-assessment methods in Jiaozhou Bay,China     

WU Zaixing  YU Zhiming  SONG Xiuxian  CAO Xihua  YUAN Yongquan 《中国海洋湖沼学报》2019,(5)

Increasing numbers of approaches to assess eutrophication,such as estuarine trophic status,the Oslo-Paris Commission Common Procedure,and the Water Framework Directive,focus on the symptoms of eutrophication.In China,however,nutrient index methods dominate the assessment of coastal waters.In this study,an integrated method that includes both water quality and ecological response was compared with the Northwest Pacific Action Plan(NOWPAP)Common Procedure.Observation data from Jiaozhou Bay,Shandong,China,were used in a comparison of the two methods in a trophic status study.Overall,both clearly revealed a high level of nutrient enrichment in the bay,indicated by high nutrient concentrations.Though the two methods differed in their methodological design in the assessment of the ecological effects of nutrient enrichment,they have acquired similar results:the integrated method suggested that the status was good,and the NOWPAP Common Procedure suggested that the status was low(indicating that the bay had no serious eutrophication problem).The introduction of filter feeders(shellfish aquaculture)into the bay on a reasonable scale may have been effective in mitigating eutrophic conditions,and perhaps explains the low ecological impacts there.Our results will be useful to ecosystem-based eutrophication management in the bay and in similar areas.  相似文献   

Incorporating dynamic factors for improving a GIS‐based solar radiation model     

Mingxi Zhang  Bin Wang  De Li Liu  Jiandong Liu  Hong Zhang  Puyu Feng  Dongdong Kong  James Cleverly  Xihua Yang  Qiang Yu 《Transactions in GIS》2020,24(2):423-441

Solar radiation has been a major input to agricultural, hydrological, and ecological modeling. However, solar radiation is usually influenced by three groups of dynamic factors: sun–earth position, terrain, and atmospheric effects. Therefore, an integrated approach to accurately consider the impacts of those dynamic factors on solar radiation is essential to estimate solar radiation over rugged terrain. In this study, a spatial and temporal gap‐filling algorithm was proposed to obtain a seamless daily MODIS albedo dataset. A 1 km‐resolution digital elevation model was used to model the impact of local topography and shading by surrounding terrain on solar radiation. A sunshine‐based model was adopted to simulate radiation under the influence of clouds. A GIS‐based solar radiation model that incorporates albedo, shading by surrounding terrain, and variations in cloudiness was used to address the spatial variability of these factors in mountainous terrain. Compared with other independent solar radiation products, our model generated a more reliable solar radiation product over rugged terrain, with an R² of 0.88 and an RMSE of 2.55 MJ m^?2 day^?1. The improved solar radiation products and open source app can be used further in practice or scientific research.  相似文献   

改性粘土絮凝法对太平洋牡蛎(Crassostrea gigas)稚贝的影响   总被引：1，自引：0，他引：1  

高咏卉  俞志明  宋秀贤  曹西华 《海洋通报》2007,26(3):53-60

本实验以太平洋牡蛎稚贝(Crassostrea gigas,～0.2cm)为对象,研究了HDTMA有机改性粘土和PAC无机改性粘土絮凝法治理赤潮时对海洋底栖生物的影响。96h急性毒性实验中二者对牡蛎稚贝的半致死浓度(LC50)分别为4.62g/L和2.67g/L。在能够有效去除赤潮微藻的浓度条件下(0.10g/L),经慢性毒性实验发现改性粘土对牡蛎稚贝成活率无影响,牡蛎生长速度较对照组没有明显差异,滤食率比培养实验初始时升高了3～4倍,同时在牡蛎超微组织结构中未发现机械损伤。通过模拟改性粘土去除赤潮生物(Heterosigma akashiwo和Prorocentrum donghaiense)过程中对生物体的影响,发现改性粘土絮凝法通过去除赤潮藻能显著提高牡蛎的存活率,所以HDTMA有机改性粘土和PAC无机改性粘土絮凝法在赤潮生物防控中可以作为一项有效的应急措施。  相似文献   

A micromorphic elastoplastic model and finite element simulation on failure behaviors of granular materials     

Chenxi Xiu  Xihua Chu 《国际地质力学数值与分析法杂志》2020,44(4):484-515

One of the purposes in this study is to develop a modified micromorphic continuum model for granular materials on the basis of a micromechanics approach. A symmetric curvature tensor is proposed in this model, and a symmetric couple stress tensor is derived conjugating the symmetric curvature tensor. In addition, a correct derivation is presented to obtain the symmetric stress tensor conjugated with the symmetric strain tensor. The modified model provides a complete deformation mode for granular materials by considering the decomposition for motions (displacement and rotation) of particles. Consequently, the macroscopic constitutive relationships and constitutive moduli are derived in expressions of the microstructural information. Furthermore, the balance equations and boundary conditions are obtained for the modified micromorphic model. By considering the extended Drucker-Prager yield criterion, the micromorphic elastoplastic model is developed. Another purpose of this study is to derive the finite element formulation for the developed micromorphic elastoplastic model. Based on the ABAQUS user element (UEL) interface, numerical simulations investigated the load-displacement relationship and the strain localization behavior of granular materials and investigated the influence of microscopic parameters in the micromorphic model on these macroscopic mechanical responses. Numerical results illustrate the presented model's capability of simulating the strain-softening and strain localization behaviors, and the capability of considering the influence of microstructural information on the macroscopic mechanical behaviors of granular materials.  相似文献   

Nitrogen and phosphorus budgets of the Changjiang River estuary     

���鰲  ��־��  ������  ������  Ԭӿ�� 《中国海洋湖沼学报》2011,29(4):762-774

Eutrophication has emerged as a key environmental problem in Chinese coastal waters, especially in the Changjiang (Yangtze) River estuary. In this area, large nutrient inputs result in frequent harmful algal blooms and serious hypoxia in bottom waters. Four cruises were made in the estuary in 2006 to assess the concentration and distribution of dissolved inorganic nitrogen (DIN) and phosphorus (DIP). The concentration of DIN decreased gradually in a linear relationship with salinity from the river mouth to ...  相似文献   

Fractal dimensions of flocs between clay particles and HAB organisms   总被引：1，自引：0，他引：1  

������  ��־��  ������  ������ 《中国海洋湖沼学报》2011,29(3):656-663

The impact of harmful algal blooms (HABs) on public health and related economics have been increasing in many coastal regions of the world. Sedimentation of algal cells through flocculation with clay particles is a promising strategy for controlling HABs. Previous studies found that removal efficiency (RE) was influenced by many factors, including clay type and concentration, algal growth stage, and physiological aspects of HAB cells. To estimate the effect of morphological characteristics of the aggregates on HAB cell removal, fractal dimensions were measured and the RE of three species of HAB organism, Heterosigma akashiwo, Alexandrium tamarense, and Skeletonema costatum, by original clay and modified clay, was determined. For all HAB species, the modified clay had a higher RE than original clay. For the original clay, the two-dimensional fractal dimension (D2) was 1.92 and three-dimensional fractal dimension (D3) 2.81, while for the modified clay, D2 was 1.84 and D3 was 2.50. The addition of polyaluminum chloride (PACl) lead to a decrease of the repulsive barrier between clay particles, and resulted in lower D2 and D3. Due to the decrease of D3, and the increase of the effective sticking coefficient, the flocculation rate between modified clay particles and HAB organisms increased, and thus resulted in a high RE. The fractal dimensions of flocs differed in HAB species with different cell morphologies. For example, Alexandrium tamarense cells are ellipsoidal, and the D3 and D2 of flocs were the highest, while for Skeletonema costatum, which has filamentous cells, the D3 and D2 of flocs were the lowest.  相似文献   

平安驿井下地温的震例分析     

庞希华  杜娟  李新华  裴青莉 《高原地震》1995,(4)

本文介绍了平安驿井下地温的概况，总结分析了１９９４年共和几次中强地震和１９９５年７月甘肃永登地震震前该测点的前兆特征并通过震例分析归纳出短临异常特征及映震指标。  相似文献