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71.
随着我国油田相继进入开发后期,传统的滤料及设备过滤精度已不能满足注水的要求。因此,研究并开发了具有一定抗油污能力的新型过滤材料,设计了新型的超精细过滤器系列产品。对滤料进行的室内实验结果表明,在开始过滤的近10h内,过滤后的水中含油量基本上满足注水的水质要求。在开始过滤的近20h内,滤层的水头损失随时间的变化较为平缓;随着过滤时间的延长,水头损失变化加剧。从现场实验可以看出,所设计的过滤器有良好的过滤性能和抗冲击能力。新型过滤材料的研究成功解决了油田含油污水精细过滤的问题,新型过滤器也是含油污水超精细过滤的理想产品。 相似文献
72.
在对废水中的BOD5进行常规分析时,采用化学稀释法操作繁琐,对稀释倍数估计易发生错误。而利用TraK装置测试样品时,无须进行稀释和化学分析。用该装置对标准样品BOD5的测定结果表明:准确度相对误差为-3.3%~4.3%,精密度的相对误差为-3.5%~5.6%。该仪器测试性能可靠,数据准确度、精密度合格。与化学法对照分析表明,相对误差都在容许范围内,即在可接受范围内。 相似文献
73.
随着计算机网络的不断发展,现有的防火墙体系已不能满足要求,发展新的网络防火墙技术已非常重要.分布式防火墙具有明显的防护优势,了解分布式防火墙技术,并在实际应Ζ用中用好它,已成为保障我们网络安全的必要. 相似文献
74.
介绍了如何在国家级生态示范区的可持续发展评估中运用灰色系统理论构建定量评估系统模型,并给出了关系型指标表、量纲模型、多元灰色预测模型和发展系数模型以及应用实例.根据该评估系统模型所开发的灰色评估系统由数学模型、计算机软件和硬件组成,可自动完成量纲统一、指标预测、相关分析、综合评估和趋势图表的运算和输出. 相似文献
75.
厌氧-好氧一体化反应器处理高浓度有机废水的运行特性研究 总被引:4,自引:0,他引:4
本实验采用新型厌氧—好氧一体化反应器处理高浓度有机废水,主要研究了系统的启动与运行性能,并对系统的NH3 N去除效果作了初步考察。实验结果表明:在16℃~24℃的自然温度下,采用递增负荷、厌氧和好氧分期启动的方式,系统可在38天内达到较好的启动效果;在系统负荷运行期内,当系统总进水COD浓度平均值为3601 8mg/L,总出水COD浓度平均值为384 0mg/L,系统容积负荷平均值为2 54kgCOD/(m3·d),系统总HRT平均值为35 1h时,系统总COD去除率平均值达90 6%。实验还发现:当进水NH3 N浓度为280 3~350 7mg/L,整个系统的NH3 N去除率在68 5%~91 7%,平均为81 0%。由此说明,本反应器具有很好的COD去除性能和NH3 N去除效果,适合于处理COD浓度高且含有中等NH3 N浓度的有机废水。 相似文献
76.
洗毛废水中含有重要的工业原料羊毛脂,不做回收处理排放到环境中就是"三废",既污染了环境又浪费了资源.介绍了用超滤膜从洗毛废水中回收羊毛脂的工艺技术,经处理的洗毛废水CODcr去除率达95.5%,BOD5去除率达93.1%,有效的回收了羊毛脂,经济效益良好,符合国家环保产业政策. 相似文献
77.
Marko S. Markov 《The Environmentalist》2005,25(2-4):67-74
Summary We often do not realize how fast the time is running. It is now more than a year since the sad news for the death of William
Ross Adey came. With kind agreement of Prof. Kostarakis my presentation at the 3rd International Workshop “Biological Effects
of Electromagnetic Fields” was dedicated to the memory of this remarkable scientist, dear colleague and friend. I would like
that this paper will be a tribute to the life and scientific achievements of Dr. Ross Adey. It is astonishing that among all
his contributions in the field of Bioelectromagnetics, Dr. Adey introduced the term “window”. 相似文献
78.
Effects of productivity on biodiversity in forest ecosystems across the United States and China
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In the global campaign against biodiversity loss in forest ecosystems, land managers need to know the status of forest biodiversity, but practical guidelines for conserving biodiversity in forest management are lacking. A major obstacle is the incomplete understanding of the relationship between site primary productivity and plant diversity, due to insufficient ecosystem‐wide data, especially for taxonomically and structurally diverse forest ecosystems. We investigated the effects of site productivity (the site's inherent capacity to grow timber) on tree species richness across 19 types of forest ecosystems in North America and China through 3 ground‐sourced forest inventory data sets (U.S. Forest Inventory and Analysis, Cooperative Alaska Forest Inventory, and Chinese Forest Management Planning Inventory). All forest types conformed to a consistent and highly significant (P < 0.001) hump‐shaped unimodal relationship, of which the generalized coefficients of determination averaged 20.5% over all the forest types. That is, tree species richness first increased as productivity increased at a progressively slower rate, and, after reaching a maximum, richness started to decline. Our consistent findings suggest that forests of high productivity would sustain few species because they consist mostly of flat homogeneous areas lacking an environmental gradient along which a diversity of species with different habitats can coexist. The consistency of the productivity–biodiversity relationship among the 3 data sets we examined makes it possible to quantify the expected tree species richness that a forest stand is capable of sustaining, and a comparison between the actual species richness and the sustainable values can be useful in prioritizing conservation efforts. 相似文献
79.
Ana Novoa Johannes J. Le Roux David M. Richardson John R.U. Wilson 《Conservation biology》2017,31(5):1066-1075
Ornamental horticulture has been identified as an important threat to plant biodiversity and is a major pathway for plant invasions worldwide. In this context, the family Cactaceae is particularly challenging because it is considered the fifth most threatened large taxonomic group in the world; several species are among the most widespread and damaging invasive species; and Cactaceae is one of the most popular horticultural plant groups. Based on the Convention on International Trade in Endangered Species of Wild Flora and Fauna and the 11 largest online auction sites selling cacti, we documented the international cactus trade. To provide an in‐depth look at the dynamics of the industry, we surveyed the businesses involved in the cactus trade in South Africa (a hotspot of cactus trade and invasions). We purchased seeds of every available species and used DNA barcoding to identify species to the genus level. Although <20% of this trade involved threatened species and <3% involved known invasive species, many species were identified by a common name. However, only 0.02% of the globally traded cacti were collected from wild populations. Despite a large commercial network, all South African imports (of which 15% and 1.5% were of species listed as threatened and invasive, respectively) came from the same source. With DNA barcoding, we identified 24% of the species to genus level. Based on our results, we believe that if trade restrictions are placed on the small proportion of cacti that are invasive and there is no major increase in harvesting of native populations, then the commercial trade in cactus poses a negligible environmental threat. However, there are currently no effective methods for easily identifying which cacti are traded, and both the illicit harvesting of cacti from the wild and the informal trade in invasive taxa pose on‐going conservation challenges. 相似文献
80.
JONATHAN M. JESCHKE SVEN BACHER TIM M. BLACKBURN JAIMIE T. A. DICK FRANZ ESSL THOMAS EVANS MIRIJAM GAERTNER PHILIP E. HULME INGOLF KÜHN AGATA MRUGAŁA JAN PERGL PETR PYŠEK WOLFGANG RABITSCH ANTHONY RICCIARDI DAVID M. RICHARDSON AGNIESZKA SENDEK MONTSERRAT VILÀ MARTEN WINTER SABRINA KUMSCHICK 《Conservation biology》2014,28(5):1188-1194
Non‐native species cause changes in the ecosystems to which they are introduced. These changes, or some of them, are usually termed impacts; they can be manifold and potentially damaging to ecosystems and biodiversity. However, the impacts of most non‐native species are poorly understood, and a synthesis of available information is being hindered because authors often do not clearly define impact. We argue that explicitly defining the impact of non‐native species will promote progress toward a better understanding of the implications of changes to biodiversity and ecosystems caused by non‐native species; help disentangle which aspects of scientific debates about non‐native species are due to disparate definitions and which represent true scientific discord; and improve communication between scientists from different research disciplines and between scientists, managers, and policy makers. For these reasons and based on examples from the literature, we devised seven key questions that fall into 4 categories: directionality, classification and measurement, ecological or socio‐economic changes, and scale. These questions should help in formulating clear and practical definitions of impact to suit specific scientific, stakeholder, or legislative contexts. Definiendo el Impacto de las Especies No‐Nativas 相似文献