基于神经网络模型的千岛湖清洁水体叶绿素a遥感反演研究

叶绿素a浓度值是水体水质评价的重要指标,研究基于高分一号(GF-1)卫星遥感影像,利用神经网络模型,选用6节点的隐含层设置,构建了千岛湖清洁水体叶绿素a浓度反演模型,对其叶绿素a浓度值时空特征进行分析,并与其他常规反演方法精确度进行比较.研究结果表明,利用神经网络模型对千岛湖清洁水体叶绿素a浓度值进行反演是可行的,且与其他常规方法相比,该模型对于叶绿素a含量低的内陆清洁水体反演有着更高的相关性(R2 = 0.921 8);在空间分布上,千岛湖区域水体叶绿素a浓度整体较低,高叶绿素a浓度区域主要集中易受人类活动干扰的西南及东北区域;年际变化分析表明,千岛湖区域水体叶绿素a浓度稳定,且波动较小,平均叶绿素a浓度值皆维持在1.70～1.75 pg/L之间,清洁水体特征显著.     

Uptake and concentration of heavy metals in dominant mangrove species from Hainan Island,South China

Environmental Geochemistry and Health - By investigating three dominant mangrove species, namely Aegiceras corniculatum, Kandelia candel, Ceriops tagal and their rhizosediment in Mangrove wetlands...     

Research progress and hot spots of hydrothermal liquefaction for bio-oil production based on bibliometric analysis

Environmental Science and Pollution Research - Hydrothermal liquefaction (HTL) of biomass used HTL reaction under high temperature and pressure to produce bio-oil. This technology is considered as...     

Comparison on surface properties and desulfurization of MnO2 and pyrolusite blended activated carbon by steam activation

In this study, MnO₂ and pyrolusite were used as the catalysts to prepare modified activated carbon, that is, AC-Mn and AC-P, respectively, from coals by blending method and steam activation. The Brunauer–Emmett–Teller (BET) results indicated that the AC-P had higher surface areas and micropore volumes than the AC-Mn with the same blending ratio. The relative contents of basic functional groups (i.e., C = O, π-π*) on AC-P were slightly lower than those on AC-Mn, while both contained the same main metal species, namely, MnO. The desulfurization results showed that with 3 wt% of blending ratio, AC-Mn3 and AC-P3 had higher sulfur capacities at 220 and 205 mg/g, respectively, which were much higher than for the blank one (149.6 mg/g). Moreover, the AC-P had relatively higher sulfur capacity than the AC-Mn with the same contents of Mn, which might be attributed to the existence of other metals in pyrolusite. After the desulfurization process, MnO were gradually transferred into MnSO₄, and the relative contents of basic functional groups decreased evidently for both AC-Mn3 and AC-P3. The results demonstrated that pyrolusite could be one good alternative to MnO₂ to prepare modified activated carbon for desulfurization.

Implications: MnO₂ and pyrolusite were used as the additives to prepare modified activated carbon from coals by a blending method and by steam activation, that is, AC-Mn and AC-P, respectively. The AC-P had higher surface areas and micropore volumes than the AC-Mn with the same blending ratio. The AC-Mn and AC-P had higher sulfur capacities than a blank one. Moreover, the AC-P had relatively higher sulfur capacity than the AC-Mn with the same contents of Mn. The results demonstrated that pyrolusite could be one good alternative to MnO₂ to prepare modified activated carbon for desulfurizatio.     

警用头盔的人机工程学分析

警用头盔是武警部队使用最为频繁的单兵防护用具，本文基于人机工程学的理论，用人机工程学的观点对武警部队现装备的警用头盔进行分析和探讨，提出解决途径的设想，展望警用头盔的发展前景。     

序批式反应器生物强化处理苯酚废水的研究

将4株高效苯酚分解菌湿菌体分3批投加于序批式反应器(SBR),对活性污泥进行生物强化试验,分析活性污泥状态与性能变化,测定生物强化后对苯酚的降解能力.结果表明,随着生物强化过程的进行,沉降性能改善,污泥颗粒化趋势明显;生物强化后,活性污泥对苯酚降解能力、降解速率及对苯酚的耐受性明显提高:苯酚质量浓度为730～960mg/L时,苯酚完全降解时间可由正常的6h缩短至2h;6h内可完全降解苯酚的质量浓度由原来的880mg/L提高到2080mg/L,处理能力提高了1.36倍;当进水苯酚质量浓度增加到2400mg/L时,6h内污泥对苯酚的降解率仍达到60.1%.     

金属探测器的现状与发展前景

目前,随着科学技术的不断发展,犯罪分子和恐怖分子也利用高新技术制造出新式的武器、爆炸物等.各个国家也对安检越来越重视.通道式安检门在整个安检过程中扮演着一个十分重要的角色.目前,在国内这个领域,国外产品占了很大一部分.国内产品与国外产品相比还有一定的技术差距.主要体现在漏报和误报.漏报是因为灵敏度达不到,误报是因为抗干扰能力较差.而国外产品在这方面却有很大的优势,因此很大一部分政府机关、企业、大型活动组织者都倾向于购买国外产品.衡量一个安检门的优势除了误报和漏报两个重要指标外,还有其它一些技术性能,也是衡量一个门质量好坏的重要参数.     

生态示范区内生态工业建设模式探讨

生态工业建设为生态示范区建设的重要内容之一 ,是一项涉及到地区经济发展、人地关系协调的重大举措。从生态示范区建设中生态工业的基本定义出发 ,对生态工业建设层次进行详尽分析 ;并结合代表江苏省苏南、苏中和苏北不同社会经济发展水平的三个地区——吴县市、邗江县和邳州市的具体案例 ,通过对其产业构成、主导产业、消费结构以及经济发展总量与人均水平的对比分析 ,指出经济发展水平较低的地区要立足当地农业资源 ,实施末端治理并逐步推广清洁生产这种较低层次的生态工业建设模式 ;而经济发展较好的地区其生态工业的建设则要采用生态企业以及生态工业园区这种较高层次的建设模式。为确保生态工业建设的顺利实施 ,最后从政府、企业、市场和公众四方面提出了生态工业建设的驱动机制     

压力板仪法测土-水特征曲线试验研究

非饱和土土-水特征曲线(SWCC)表示了土中含水量与吸力之间的关系。针对非饱和土干-湿循环过程中的吸力变化特征,开展试验研究。采用体积压力板仪实现非饱和土的脱湿和吸湿过程。试验成果显示:(1)土-水特征曲线是不稳定的,它与土体含水率的变化路径有关;(2)在干湿循环过程中,相同的基质吸力具有不同的含水量。     

优势菌的筛选及其强化活性污泥好氧反硝化的研究

利用含活性污泥提取物的贫培养基筛选SBR系统中的好氧异养优势菌。结合自然温度（15～20℃）、延长培养时间等条件来提高菌群的可培养性。从SBR活性污泥系统中分离出5种细菌。4株去除COD优势菌，1株异养硝化细菌，能在好氧条件下实现对总氮的去除。反应池底采用边缘对称曝气，反应池内细菌在时间顺序和空间位置上循环经历好氧过程及微氧过程。将PVA铝盐法固定的细菌对反应器进行生物强化。结果显示，在好氧工艺的条件下，投加优势菌群后，与未加优势菌群的反应器相比，可以显著改善污泥的沉降性能，COD、NH₃-N和TN降解率显著提高，分别达到98%、97%和90%。生物强化作用明显，反应器内具有良好的好氧反硝化环境。