Spatial-temporal analysis of wetland landscape pattern under the influence of artificial dykes in the Yellow River delta

The influence of anthropogenic activities,especially artificial dykes,on the coastal wetland landscape is now considered as a serious problem to the coastal ecosystem.It is important and necessary to analyze changes of coastal landscape pattern under the influence of artificial dykes for the protection and management of coastal wetland.Our study aimed to reveal the quantitative characteristics of the coastal wetland landscape and its spatial-temporal dynamics under the influence of artificial dykes in the Yellow River delta(YRD).It was analyzed by the methods of the statistical analysis of landscape structure,five selected landscape indices and the changes of spatial centroids of three typical wetland types,including reed marshes,tidal fiats and aquaculture-salt fields.The results showed that:(1)Reduction of wetland area,especially the degradation of natural wetlands,had been the principal problem since the dykes were constructed in the YRD.The dykes created conditions for the development of artificial wetlands.However,the new born artificial wetlands were still less than the vanished natural wetlands.(2)Compared with the open area,the building of artificial dykes significantly speeded up the changes of landscape patterns and the aggravation of the landscape fragmentation in the closed area.(3)The changes of area-weighted centroids of three typical wetland landscapes were greatly affected by dykes,and the movement of the centroid of the aquaculture-salt field was very sensitive to the dykes constructed in the corresponding period.     

Research on Tourism Competitiveness of Chinese Island Counties: Based on Factor and Cluster Analysis

Abstract

From the perspective of tourism competitiveness, the paper takes 12 island counties of China as the research object, and applies the method of factor analysis to study their competitiveness. The result shows that Putuo and Dinghai are more competitive while Pingtan and Nan’ao are less competitive. Finally, the 12 island counties are divided into four styles: first-class competitive county (Putuo), seond-class competitive counties (Dinghai,Yuhuan), third-class competitive counties (Chongming, Daishan, Changdao, Changhai and Shengsi), fourth-class competitive counties (Dongshan, Dongtou, Pingtan and Nan’ao) by cluster analysis. The classification of island counties is to clear their relative position, then to promote their development.     

Pollution characteristics and health risk assessment of polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons during heating season in Beijing

Polycyclic aromatic hydrocarbons(PAHs) and their nitrated derivatives(NPAHs) attract continuous attention due to their outstanding carcinogenicity and mutagenicity. In order to investigate the diurnal variations, sources, formation mechanism, and health risk assessment of them in heating season, particulate matter(PM) were collected in Beijing urban area from December 26, 2017 to January 17, 2018. PAHs and NPAHs in PM were quantitatively analyzed via gas chromatography-mass spectrometry(GC-MS). ...     

A large-scale outdoor atmospheric simulation smog chamber for studying atmospheric photochemical processes: Characterization and preliminary application

Understanding the formation mechanisms of secondary air pollution is very important for the formulation of air pollution control countermeasures in China. Thus, a large-scale outdoor atmospheric simulation smog chamber was constructed at Chinese Research Academy of Environmental Sciences (the CRAES Chamber), which was designed for simulating the atmospheric photochemical processes under the conditions close to the real atmospheric environment. The chamber consisted of a 56-m³ fluorinated ethylene propylene (FEP) Teflon film reactor, an electrically-driven stainless steel alloy shield, an auxiliary system, and multiple detection instrumentations. By performing a series of characterization experiments, we obtained basic parameters of the CRAES chamber, such as the mixing ability, the background reactivity, and the wall loss rates of gaseous compounds (propene, NO, NO₂, ozone) and aerosols (ammonium sulfate). Oxidation experiments were also performed to study the formation of ozone and secondary organic aerosol (SOA), including α-pinene ozonolysis, propene and 1,3,5-trimethylbenzene photooxidation. Temperature and seed effects on the vapor wall loss and SOA yields were obtained in this work: higher temperature and the presence of seed could reduce the vapor wall loss; SOA yield was found to depend inversely on temperature, and the presence of seed could increase SOA yield. The seed was suggested to be used in the chamber to reduce the interaction between the gas phase and chamber walls. The results above showed that the CRAES chamber was reliable and could meet the demands for investigating tropospheric chemistry.     

环境监测对环保工作的影响

为保证环保工作的有效性,推动环保工作不断向好发展,分析了环境监测及其分类,指出环境监测对环保工作的影响.其可为环境评价的不断完善提供数据依据,降低环境治理成本,推动环保工作高效顺利开展.提出了进一步发挥环境监测对环保工作积极影响的措施:加大资金投入力度,加强环境监测专业队伍建设力度,确保环保工作高质量高效率开展,为人们...     

高速铁路高填复合路堤边坡安全问题探讨

路基是高速铁路安全系统的关键和薄弱环节 ,建在软土上的高填路堤边坡是否稳定 ,更是直接关系到路基乃至整个高速铁路系统的安全 ,采用桩—网复合地基形式修建高路堤是一个好办法 ,这种路堤形式尚不多见。笔者结合其特点 ,从理论上提出了一种新的边坡安全实用计算方法 ;讨论了影响边坡安全的主要因素 ;验证了这一计算方法的合理性     

城市污水处理计算机控制系统的应用研究

本文通过对污水处理行业所采取的计算机控制系统进行比较分析 ,得出结论 :采用基于现场总线的PC +PLC分级分布式控制形式 ,能够使系统具有很高的性能 /价格比。同时 ,将此结构进行拓展 ,成功应用于我国第一座自主开发的城市污水处理厂———沈阳南部污水处理示范厂。在系统中采用就地操作BIU +MFP(基本接口单元 +微现场处理单元 )与主PLC相结合的控制结构 ,通过GeniusBus(现场总线 )技术实现通讯处理 ,达到节约投资、提高系统安全性的目的     

工业设备的震害预测研究

综合考虑地震作用和结构材料的随机性 ,运用概率论的知识建立了地震作用下钢铁工业设备各种破坏形式的极限状态方程 ,并求出了对应于某种地震烈度 ,设备出现各种破坏状态的概率。在此基础上 ,通过模糊综合评判的手段提出了工业设备的震害预测方法 ,并编制了相应的软件。此种方法的建立使设备抗震预测变得方便、可行。     

九寨沟自然保护区4种水深梯度下芦苇分株地上生物量的分配与生长

芦苇是世界自然遗产--九寨沟自然保护区的一种重要的湿地植物.本文对该地区芦苇海4个不同水深梯度下芦苇的无性系地上分株的生物量分配、生长与繁殖策略进行了比较研究.结果表明,在47 cm (水在土层表面上)水深环境中,芦苇单株的平均生物量(4.2 g)最大.在-15 cm (水在土层表面下15 cm)的生境中,叶生物量百分比(叶生物量占单株总生物量的百分比, 46.1%)最大.芦苇地上分株高度、地上分株有分枝的单株百分比(茎上有分枝的分株占样地总分株的百分数)也存在明显的差别.茎的生物量分配百分比和生长速率随水深的增加而增加.在滩地生境中,开花率、花序的生物量百分比明显大于水较深的生境.分株株高与分株生物量、茎生物量与叶生物量都表现出较明显的幂指数异速生长规律.在-15 cm水深的生境中,叶生物量的生长快于茎的增长;在其他水深梯度的生境中,则是茎生物量的增加快于叶生物量的增加.     

吸附法处理预焙阳极沥青烟研究现状与进展

预焙阳极生产过程中产生的沥青烟气严重污染环境并危害人类健康。目前,沥青烟的治理方法主要有四种,即吸收法、燃烧法、静电捕集法及吸附法。前三种方法处理费用高、应用范围窄,并有二次污染等问题。吸附法工艺简单、净化效率高、无二次污染,是一种很有发展前途的方法。在综合评述吸附法治理沥青烟研究及应用现状的基础上,提出了吸附法治理沥青烟今后的研究工作重点：（1）易吸附／脱附沥青烟的高效滤料开发;（2）吸附及再生装置与工艺的开发改进。