水平井钻磨管柱油管组合方式研究及下入安全性分析

基于钻磨管柱下入过程易造成遇卡事故,油田采用了2种线重油管的组合方式进行钻磨作业,提高了管柱的下入能力,但未能得到2种线重油管组合方式优选的可靠依据。为得到2种线重油管的最优组合方式,采用微元法对管柱单元在各井段的受力进行分析,建立钻磨管柱的下入载荷计算模型;采用编程对油田水平井进行实例计算,计算结果与实测结果对比显示模型平均误差在8.12%左右,验证了模型的正确性;基于下入载荷计算模型,进行了钻磨管柱组合特性研究及参数敏感性分析。结果表明:采用2种线重油管的组合方式能增大钻磨管柱下入能力,当大线重油管所占整个钻磨管柱的长度为井斜角70.8°左右的井深时,组合比例最优,不同的摩擦系数μ决定不同最优组合比例。     

城市水资源综合利用新模式探索与研究

随着经济和社会的发展,城市水资源短缺的矛盾日益突出.宁波市北仑区作为一个极度缺水的地区,在开发利用雨水、海水、再生水等非常规水资源方面积累了一些成功的案例和经验,每年可收集利用雨水近220万吨,利用各类再生水超3 500万吨,区域污水厂废水的再生利用率达到30％.从政府层面对水资源的环境价格和资源价值体现作了有益的探索,并在下一步的城市建设中积极引入“海绵城市”的概念,为其他同类型地区合理利用水资源提供参考和思路.     

税收竞争对环境污染的影响及传导机制分析

在中国经济高增长的背后,环境污染问题愈发凸显,不利于经济的可持续增长。税收竞争是影响环境污染的主要因素之一,但是学术界研究税收竞争对环境污染的影响及其作用机制的较少。本文按照污染物属性将其划分为外溢性污染物和非外溢性污染物,通过构建一个包含生产者、消费者、地方政府及中央政府的一般均衡模型,刻画了在税收竞争的背景下,地方政府的税收征管效率对不同属性污染物的影响及其传导机制。结果发现当污染物具有外溢性属性时,税收征管效率对该地环境污染的影响通过改变本地及周边地区资本存量渠道实现;当污染物具有非外溢性属性时,降低税收征管效率通过增加该地区资本存量而提高了环境污染。文章首先使用随机前沿模型测算了2007—2014年中国28个省份企业所得税的税收征管效率,并将其作为税收竞争的衡量指标,然后运用系统GMM法证实了所提的假说。研究显示:地方政府的税收竞争增加了本地区的资本存量;税收竞争是将本地资本存量作为其推高外溢性污染物(二氧化硫)及非外溢性污染物(固体废弃物)排放量的一个主要渠道,邻近地区资本存量则是推高外溢性污染物(二氧化硫)的次要渠道。这意味着,要想改善环境质量,中央政府应规范地方政府的税收竞争行为,尽快建立一套科学、有效的绿色GDP评价体系;完善地方转移支付制度;应针对各个地区的污染及经济发展情况利用财政激励手段引入环保、绿色的资本项目;地方政府应减少不利于环境改善的地方财政支出,增加环保投入比重。     

山东省电力资源空间格局及环境成本分析

基于复杂网络理论,对山东省电力网络空间结构、分布特征进行了分析.结果发现：受资源禀赋的影响,山东省电力输出端主要分布在鲁西南地区,输入端主要集中在中东部重工业城市;电力网络拓扑结构具有较小的聚类系数和较大的平均路径长度,度分布呈现出不完全幂律分布,具有向无标度网络演化的特征;受电源结构的影响,各地市发电环境成本差异较大,尤其与火电发电规模紧密联系.     

不同嫁接方式对黄瓜嫁接苗成活及生长特性的影响

研究了不同嫁接方式对黄瓜嫁接苗成活率、生物学性状及其植株抗病性的影响．结果表明：以湘园三号黄瓜作为接穗，黑籽南瓜作为砧木，采用靠接、顶插、劈切、芽接四种嫁接方式，其嫁接苗成活率分别为100．0％、78．4％、92．9％和75．5％；其平均株高、平均真叶数均以靠接苗为大，分别为15．8cm、3．0片；四种嫁接苗的平均株幅无明显差异．以津春二号黄瓜作为接穗，分别以黑籽南瓜和西葫芦作为砧木，均采用靠接方式，其靠接苗成活率分别为99．4％、100．0％，平均株高、平均株幅和真叶数均以前者为大．经嫁接后，黄瓜植株枯萎病发病率明显下降，控制在0-14．0％范围之内；而未经嫁接的津春二号（对照1）、津春三号（对照2）黄瓜植株，病株率分别达到48．0％、36．0％．     

灾后承接非政府组织援助系统工程的综合集成模式——以汶川8.0级地震为例

分析了承接非政府组织(NGO)援助复杂巨系统的框架结构、时空结构、运行结构及整体特性;提出了地震灾后承接援助系统工程的综合集成模式;分别就承接援建集成工程的运作模式和具体实施框架进行了讨论;就援建系统工程、迎建系统工程、应急组织系统工程和保障系统工程等具体实施工程做了细致的阐述。     

Experimental research of flow rate and diffusion behavior of nature gas leakage underwater

In order to assess the potential risk of pipeline underwater leakage, a self-designed experimental setup is carried out to study the gas release rate and dispersion behavior in different release scenarios. A transparent organic glass tank with dimension of 1 m × 0.5 m × 0.5 m (height × width × length) was placed in a wind tunnel. The release pipeline made by stainless-steel with diameter of 25 mm were used to simulate for variation release depth. The different size and shape of leakage orifices in 1 mm, 3 mm, 5 mm in round and 3.5 × 2 mm, 7 × 1 mm in rectangle were designed for comparison. The medium of methane gas was released from the controllable cylinder. The variation parameters of flow rate and pressure were measured by a flow meter and pressure gauge respectively. A high speed camera was employed to recorded the phenomenology of dispersion characteristics and breakup process for a wide range of orifice size in the time-resolved images. The dynamic plume diameter on water surface was measured by a Vernier caliper placed above the water tank. The considered factors including orifice size, leakage pressure and water depth effect on gas flow rate and dispersion behavior was quantitative investigated. The fitting correlation between the gas flow rate and variation parameters can provide fundamental information for evaluation the hazard consequences of gas release in engineering application.     

Residues,half-life times,dissipation, and safety evaluation of the acaricide fenpyroximate applied on grapes

A validated high-performance liquid chromatography–diode array detector method for simultaneous determination of the acaricide fenpyroximate on grape was developed. Estimated limit of detection and limit of quantification for fenpyroximate were 0.01 and 0.05 mg kg^?1, respectively. The intra- and inter-day precisions performed with relative standard deviation were better than 9.3% and 8%, respectively, while recoveries were in the range of 88.5%–100.4%. Residue levels of fenpyroximate in grape samples collected 10 days after field application were below the established maximum residue level values. The dissipation rates of fenpyroximate were described using first-order kinetics and its half-life, were approximately 3.5 days in grape. This study provides basic information for developing regulations to safeguard the use of fenpyroximate in grapes and prevent any potential health concerns for consumers.     

FUNCTIONAL SIGNIFICANCE OF SPECIES COMPOSITION IN RIPARIAN PLANT COMMUNITIES1

ABSTRACT: This paper analyzes the spatial patterns of plant species richness observed in 1989 and in 1999 alongside the Adour River (Southwest France), focussing on: (1) upstream‐to‐down‐stream changes, (2) mid‐term changes, and (3) differences in observed patterns among various plant functional groups. The purpose of the research was to analyze how the proportions of invading species and/or ruderal species within riparian corridors can be related to regional environmental settings. About half of native and exotic species were ruderals. However, the proportion of competitors was higher within the native pool. No correlation was found between exotic and native functional groups. The longitudinal distribution of native and exotic ruderal species were correlated together, but they were not correlated with the total species richness. Converse to observations at the local scale in other studies, these patterns seem to be driven more by factors co‐varying with the size of the river and by climatic factors than by hydrological disturbance‐related factors. The role of the various plant groups studied and potential consequences on ecosystem function are discussed in the context of an increasing susceptibility of our ripanan corridors to invasions by nonriparian species. Management perspectives are discussed for the purpose of biodiversity conservation.