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751.
以木质素磺酸钠为原料单体、环氧氯丙烷为交联剂,采用反相乳液聚合法制备了木质素磺酸钠交联聚合物(SLCP),并将其用于水中有机染料的吸附。表征结果显示:SLCP基本保留了木质素磺酸钠的骨架和官能团,具有良好的热稳定性。实验结果表明:SLCP对亚甲基蓝(MB)有较好的吸附选择性,在加入量为0.5 g/L时就有较高的吸附效率;在溶液p H2~6范围内吸附量随溶液p H增大而迅速提高,溶液p H6后吸附量趋于稳定;最佳吸附温度为35℃;在SLCP加入量0.5 g/L、溶液p H 6.5、吸附温度25℃、初始MB质量浓度100.5 mg/L的条件下,吸附150 min基本可达平衡,吸附平衡时的吸附量和MB去除率分别为191.2 mg/g和95.1%;SLCP对MB的吸附符合Langmuir等温吸附模型,吸附动力学符合Lagergren拟二级动力学方程。  相似文献   
752.
针对等孔径喷吹管,利用CFD软件对其内流场进行数值模拟,得到不同入口流量条件下的流场分布特性。对喷吹管进行非稳态流场模拟,并与稳态模拟结果分析比较,模拟结果误差控制在1%以内,验证了将喷吹管非稳态内流场简化为稳态流场分析具有一定的可行性。沿着喷吹管气流流动方向,喷嘴出口流量分布不均匀,整体有增大的趋势;沿喷吹管轴向气流渐趋均匀,即越靠近端面,喷吹偏心角越小,甚至为0。  相似文献   
753.
介绍了酸雨对混凝土建筑物和文物损坏机理的宏观分析,水泥中加入少量石膏,可延缓凝结时间,但当加入量大,将引起水泥膨胀,以致溃裂,探讨了酸雨对混凝土建筑物与文物损坏的微观分析,特别是酸雨等生成各种硫酸盐,通过从化学反应原理上分析了酸雨中二氧化硫与混凝土中钙离子反应生成石膏机理,从石膏特性上探讨了酸雨对混凝土建筑物和文物侵蚀机制,并由此提出了酸雨条件下保护混凝土建筑物和文物应对措施。  相似文献   
754.
摘 要:分析了我国工业锅炉、水泥玻璃窑炉、化工厂和酸洗设备面临的烟气脱硫脱硝难题,针对低温SCR催化剂开发情况和应用实例,介绍了我国低温SCR技术的发展;综述了活性焦法低温烟气脱硫脱硝工艺和湿法有机催化氧化烟气脱硫脱硝技术的工艺原理、流程和技术特点,并通过工程案例进行了运行经济评估。  相似文献   
755.
This study was conducted to evaluate cyhalofop‐p‐butyl mobility in a sandy loam soil and subsequent distribution of residues at various depths under field conditions. Soil samples were taken from 0 to 150 cm depths at 3–90 d after rains in lysemeter of 1 and 2 m depths. Cyhalofop‐p‐butyl application at two rates and subsequent precipitation had a significant impact on soil, physico‐chemical properties and herbicide mobility. Precipitation caused substantial mobility of cyhalofop‐p‐butyl in the soil and 1.1–7.6 μg L?1 of cyhalofop‐p‐butyl was found in leachates. Cyhalofop‐p‐butyl residues in the leachates were probably due to preferential flow through the soil. Cyhalofop‐p‐butyl residues were detected in significant amounts from the soil up to 10 d, later, residues were found below the detection limit but its three transformation products viz., cyhalofop acid, diacid, and phenol were detected.  相似文献   
756.
本文报道了2,4-二羟基-5-安替比林偶氮苯甲醛(DAP)及DAP与聚乙烯醇(PVA)的缩合产物(PV·DAP)的合成.并利用PV·DAP做萃取剂,析相萃取和光度测定了铝合金和环境水样中的镍.实验结果还表明,高分子显色剂与相应的小分子试剂相比,在液-固萃取方面表现为易获得高萃取率且不受萃合物电性的影响,在光度测定方面则表现出较高的灵敏度和稳定性.从而说明试剂的高分子化可改善其性能.  相似文献   
757.
ABSTRACT: Concrete block irrigation diversion systems have been proposed as alternatives to permanent dams of concrete or rock or temporary gravel berms. Permanent dams can cause stream channel instability, bank erosion, sediment pollution, ice flow blockage, and safety problems for recreational floating craft. Temporary berms can require substantial streambed disturbance and can promote sediment pollution, stream bank instability, and bank erosion. A design procedure was developed based on a model of the hydraulic performance of concrete block diversion systems. The procedure was used to model a site on the Gallatin River in Montana. The method relies on HEC-RAS (Hydrologic Engineering Center -River Analysis System) software combined with analytical techniques in an iterative scheme. The hydraulic performance of different diversion configurations (the existing heavy-rock diversion system, concrete blocks oriented parallel to flow, and concrete blocks oriented diagonally) was assessed using the model under a range of flow rates. The minimum diversion dimensions (length, number, and size of blocks) that maintained block stability while diverting the requisite flow were determined for each model run. At the Gallatin River site, the block system oriented parallel to flow required less diversion material than the diagonal orientation. The recommended diversion length was 51.8 m (170 ft). Trapezoidal blocks with a top width of 20.3 cm (8 in), a height of 45.7 cm (18 in), and side slopes of 2 vertical to 1 horizontal were specified. This configuration minimizes the total block mass, diverts the required flow, and has a factor of safety of 2.0 against block displacement.  相似文献   
758.
Marine-protected areas (MPAs) are vital to marine conservation, but their coverage and distribution is insufficient to address declines in global biodiversity and fisheries. In response, many countries have committed through the Aichi Target 11 of the Convention on Biological Diversity to conserve 10% of the marine environment through ecologically representative and equitably managed MPAs by 2020. The rush to fulfill this commitment has raised concerns on how increasing MPA coverage will affect other elements of Target 11, including representation and equity. We examined a Philippines case study to assess and compare 3 MPA planning approaches for biodiversity representation and equitable distribution of costs to small-scale fishers. In the opportunistic approach, MPAs were identified and supported by coastal communities. The donor-assisted approach used local knowledge to select MPAs through a national-scale and donor-assisted conservation project. The systematic conservation planning approach identified MPA locations with the spatial prioritization software Marxan with Zones to achieve biodiversity objectives with minimal costs to fishers. We collected spatial data on biodiversity and fisheries features and performed a gap analysis to evaluate MPAs derived from different approaches. We assessed representation based on the proportion of biodiversity features conserved in MPAs and distribution equity by the distribution of opportunity costs (fishing areas lost in MPAs) among fisher stakeholder groups. The opportunistic approach did not ineffectively represent biodiversity and resulted in inequitable costs to fishers. The donor-assisted approach affected fishers disproportionately but provided near-optimal regional representation. Only the systematic approach achieved all representation targets with minimal and equitable costs to fishers. Our results demonstrate the utility of systematic conservation planning to address key elements of Target 11 and highlight opportunities (e.g., integration of local and scientific knowledge can address representation and equity concerns) and pitfalls (e.g., insufficient stakeholder considerations can exacerbate social inequalities) for planning MPAs in similar contexts.  相似文献   
759.
机械修理行业产生的高浓油皂洗涤废水中含大量的油、皂、未失效的清洗剂及其他成分,水处理难度较大.笔者在小试及中试基础上确定了破乳除油皂、回收清洗剂的资源化工艺路线,并确定了最佳工艺参数.   相似文献   
760.
取代苯对人体细胞的定量结构—遗传毒性研究   总被引:1,自引:1,他引:0       下载免费PDF全文
通过微核实验,测定了 36 种取代苯类化合物对人体外周血淋巴细胞的遗传毒性;并构建了遗传毒性与分子结构参数之间的 QSAR 模型.结果表明,有 34 种化合物显著地导致了微核的产生,具有明显的遗传毒性;遗传毒性的大小与分子结构描述符辛醇-水分配系数(MlogP)、x 轴主惯性矩(Principalx)、γ 极化率[Polar(γ)]等存在良好的结构-活性相关关系,所建模型的相关系数 R2 =0.718,具有较高的预测能力,可用来预测取代苯类化合物的遗传毒性.  相似文献   
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