煤岩电磁辐射信号时间序列混沌特性分析

采用华丰矿1409工作面电磁辐射观测数据,应用相空间重构法计算了5次矿震前后系统混沌吸引子的关联维数D2。研究结果表明:电磁辐射时间序列具有混沌特征,混沌系统的自由度在2~26之间。矿震发生前,混沌吸引子的关联维数D2先升后降,矿震过程中系统有降维现象。研究结果对认识矿震过程中煤岩体产生的电磁辐射信号的非线性特征和进行矿震预报具有一定的参考价值。     

A Special Vegetation Index for the Weed Detection in Sensor Based Precision Agriculture

Many technologies in precision agriculture (PA) require image analysis and image- processing with weed and background differentiations. The detection of weeds on mulched cropland is one important image-processing task for sensor based precision herbicide applications. The article introduces a special vegetation index, the Difference Index with Red Threshold (DIRT), for the weed detection on mulched croplands. Experimental investigations in weed detection on mulched areas point out that the DIRT performs better than the Normalized Difference Vegetation Index (NDVI). The result of the evaluation with four different decision criteria indicate, that the new DIRT gives the highest reliability in weed/background differentiation on mulched areas. While using the same spectral bands (infrared and red) as the NDVI, the new DIRT is more suitable for weed detection than the other vegetation indices and requires only a small amount of additional calculation power. The new vegetation index DIRT was tested on mulched areas during automatic ratings with a special weed camera system. The test results compare the new DIRT and three other decision criteria: the difference between infrared and red intensity (Diff), the soil-adjusted quotient between infrared and red intensity (Quotient) and the NDVI. The decision criteria were compared with the definition of a worse case decision quality parameter Q, suitable for mulched croplands. Although this new index DIRT needs further testing, the index seems to be a good decision criterion for the weed detection on mulched areas and should also be useful for other image processing applications in precision agriculture. The weed detection hardware and the PC program for the weed image processing were developed with funds from the German Federal Ministry of Education and Research (BMBF).     

Airborne Dust Particle Counting Techniques

The paper briefly describes an electro-optical system for counting of dust particles, which is based on the scattering phenomena.Utilizing the scattering of light by various size particles present in the environment, various particle counting techniques have been developed in order to measure the scattered intensity of light. Light scatters in all directions but much more in the so-called near forward direction 17^∘ off axis, at 163^∘ from the light source in the visible range.On the basis of two techniques, the right angle and forward angle scattering, opto-mechanical systems have been developed which measure scattered intensity and particulate matter. The forward scattering Nephelometer is more sensitive and therefore is more suitable for pollution monitoring than the right angle scattering Nephelometer. Whereas the right angle scattering Nephelometer has the utility in extremely low concentration in ppb level owing to the excellent light trap efficiency in comparison to forward scattering Nephelometer. In this paper measurement techniques and measurement results associated with design and development of a real time particle analyser are also discussed.     

Quantifying The Rainfall-Water Level Fluctuation Process in a Geologically Complex Lake Catchment

Abstact Simulating hydrologic processes in geologically complex environments is a difficult scientific task since it incorporates high level of uncertainty. Many studies have attempted to accurately quantify the rainfall-water level elevation relationship in freshwater bodies so as to predict flooding and drought events. For this purpose several types of models have been implemented including distributed, black box and conceptual models that often provide efficient results, depending on the availability of reliable data as well as on the level of understanding of the system. Nevertheless, in the particular effort, three different models have been used to describe the relationship between rainfall and water level elevation in Trichonis Lake during the period 1951–1997. A Transfer Function model, a Dynamic Linear Regression and a physically based model, consisting of the lake's water budget equation, its Digital Bathymetric Model and GIS algorithms. These models have been tested to assess their efficiency and applicability in a karstic environment and the aim of the study was to find the best modeling option for developing sustainable water management plans and establishing a flooding/drought warning system in the particular lake catchment. The results indicated that in areas with geologically complex conditions, simple, physically-based models operate better than mechanistic models which usually cannot describe adequately the complexity of the system     

The Status of Pesticide Residues in the Drinking Water Sources in Meiliangwan Bay, Taihu Lake of China

The study was carried out to assess the levels of pesticide residues in the water of Meiliangwan Bay, Taihu Lake of China. The most commonly employed organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs) and herbicide atrazine were analyzed. The water samples were collected seasonally from Meiliangwan Bay within a period of one year. The pesticides were analyzed by gas chromatography (GC) with μECD or NPD after solid-phase extraction (SPE), which was confirmed by GC with an ion trap mass spectrometry (MS). The mean concentrations were 1.98 ng/l for lindane, 0.378 ng/l for heptachlor epoxide, 0.367 ng/l for p,p′-DDE, 0.496 ng/l for p,p′-DDD, 1.06 ng/l for p,p′-DDT and 51.6 ng/l for dichlorvos, 39.0 ng/l for demeton, 346 ng/l for dimethoate, 4.12 ng/l for methyl parathion, 11.6 ng/l for malathion, 2.17 ng/l for parathion and 217 ng/l for atrazine. Generally, low concentrations of OCP were found, whereas the concentrations of the OPPs and atrazine in the water of Taihu Lake were relatively high. Heptachlor epoxide and lindane were the two most commonly encountered OCPs while dichlorvos, demeton and dimethoate were found to have much higher concentrations and occurrences than other OPPs.     

人力资源管理在安全生产中的作用

针对导致事故发生的人的因素,从人力资源管理角度研究如何预防和控制事故,并探讨了方法,提出了有效措施,以构建企业和谐的安全生产环境,提高企业的安全管理水平,促进企业健康有序发展.     

燃煤电厂排放PAHs的气粒分配机制和排放通量

对循环流化床锅炉(CFB)布袋除尘器进口和出口的多环芳烃(PAHs)进行了分析,研究了PAHs在气相和颗粒相中的分配机理.结果表明,除尘过程气相和颗粒相PAHs对应的去除率分别为45.59％与70.67％～89.06％.气相中主要为低分子量PAHs,颗粒相中主要为高分子量PAHs.随着粒径的增加,低分子量PAHs比例呈...     

城市生活垃圾填埋场渗滤液生化处理过程中重金属离子问题

我国对城市生活填埋场渗滤液处理技术的研究主要集中在COD与NH4 -N的去除上,对渗滤液中重金属离子的专项研究几乎未见报道.本文首先总结了国内外城市生活垃圾渗滤液中重金属的种类及浓度,在渗滤液中的存在状态,渗滤液中重金属与其他成分(有机物、氨氮)的相互作用关系,辨证分析了重金属在渗滤液生化处理过程中的有益作用和毒性,归纳了重金属在渗滤液生化处理过程中的变化规律,同时总结分析了重金属的去除技术.     

Perception and Attitude of Residents Toward Urban Green Spaces in Guangzhou (China)

Fast economic and social changes in recent years in China have brought massive expansion, redevelopment, and restructuring of cities. These changes offer cities the opportunity to improve environmental quality through urban green spaces (UGSs) and to address the challenges of meeting community aspirations. This study explored peoples’ minds concerning UGSs in Guangzhou city in south China in relation to the following: (1) knowledge and perception of 25 ecosystem services and 8 negative impacts; (2) attitude toward site condition and management; (3) expectation of landscape design; and (4) preference ranking of venues. A questionnaire was designed to solicit opinions from 340 respondents randomly chosen from residents living in the study area. The results indicated widespread recognition of ecosystem services and strong support of UGS programs. Negative responses were weakly expressed. Amelioration of urban microclimate and environmental quality were emphasized. Environmental functions stressed in publicity programs, together with aggravating environmental problems in the city, tended to focus respondents’ attention on UGS benefits. Wildlife habitat, species conservation and other natural ecosystem services drew limited concerns. Awareness of economic benefits was very low. Visual-landscape contributions with strong preference for naturalistic design and recreational benefits were highlighted. Compared with other countries, Guangzhou residents were characterized by visual–scenic–recreation orientation and pragmatic–utilitarian perception of UGSs, reflecting underlying differences in the understanding of inherent ecosystem services of green spaces. Relevant UGS policies and practices could adopt the approaches of market survey, citizen participation, and precision planning in order to meet increasingly mature and refined demands. Citizens’ understanding of high-order ecosystem services could be enhanced to encourage appreciation of nature and their associated benefits.     

固相萃取小柱净化-气相色谱法测定土壤和沉积物中有机氯和拟除虫菊酯农药残留

建立了毛细管气相色谱法测定土壤和沉积物中α-六六六,β-六六六,γ-六六六,δ-六六六,硫丹,p,p'-DDE,p,p'-DDD,o,p'-DDT,p,p'-DDT,三氯杀螨醇,甲氰菊酯,氯氰菊酯,联苯菊酯,氟氯氰菊酯,氰戊菊酯,溴氰菊酯等16种农药残留量的方法.16种农药的残留组分在25min内能很好分离.标准加入回收率在81.2%-111.9%之间;方法变异系数2.9%-14.9%(0.01-0.1μg·ml-1,n= 6),检出下限在0.08-0.44μg·kg-1之间.