Species analysis methods for hydrolysis polymerization of aluminum

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基于i1Mx-27的视频监控终端的设计和实现

介绍了一种基于新一代多媒体应用平台i.Mx-27和嵌入式Linux的图像采集和远程监控系统。阐述了系统各模块的硬件构成,系统的运行原理和软件设计。该终端实现了使远程PC通过Web浏览器方式进行实时视频监控。     

聚硅氯化铝（PASC）的形态分布及转化规律：Ⅱ.^27Al—NMR法研究PASC溶 …

采用＾２７Ａｌ－ＮＭＲ法比较研究了ＰＡＳＣ与ＰＡＣ中铝的形态分布。实验结果表明,在ＰＡＳＣ中,由于聚硅酸与铝水解聚合物产物间的相互作用,使得铝的水解聚合形态分布及转化情况发生了变化。在相同Ｂ值条件下,ＰＡＳＣ中Ａｌ单和Ａｌ１３的含量低于ＰＡＣ中相应Ａｌ单和Ａｌ１３的含量,而ＰＡＳＣ中Ａｌ其它的含量大于ＰＡＣ中Ａｌ其它的含量,其差值随着碱化度（Ｂ）和Ａｌ／Ｓｉ摩尔比的减小而增大。     

Synchronous removal of CuO nanoparticles and Cu2+ by polyaluminum chloride-Enteromorpha polysaccharides: Effect of Al species and pH

Copper oxide nanomaterials have been extensively applied and can have serious impacts when discharged into the aquatic environment, especially when complexed with humic acid (HA) to form composite contaminants. As an innovative recycled coagulant aid, Enteromorpha polysaccharides (Ep) were associated with polyaluminum chloride (PACl) (denoted as PACl-Ep) to simultaneously remove CuO nanoparticles, Cu²⁺ and HA in this study. The influence of different Al species coagulants (AlCl₃, PACl_b and PACl_c) and water pH on coagulation performance, floc properties and reaction mechanisms was investigated in detail. Results showed that in the three PACl-Ep systems, PACl_b-Ep gave the highest removal efficiencies for turbidity and Cu²⁺, and the best UV₂₅₄ removal effect was reached by using PACl_c-Ep. Higher contents of Al_b and Al_c contributed to great coagulation performance because of their stronger bridging and sweeping effects. For all the Al species coagulants, alkalescent conditions were more conducive to removing Cu and HA compared to acidic conditions. Additionally, smaller and more agminated flocs with great recovery ability were formed by PACl_b-Ep and PACl_c-Ep systems (bridging and enmeshment effects cooperated with the chelated reticular structure formed by the Ep and Al species). Similarly, due to the increased hydrolysis and hydroxide precipitates, flocs formed under the condition of alkalescence were smaller, denser and stronger compared with weakly acidic conditions.     

聚合硅酸硫酸铝溶液中铝的形态分布及转化规律

以硫酸铝、水玻璃和铝酸钠为原料合成出了具有不同碱化度(B)和si／Al摩尔比的聚合硅酸硫酸铝(PASS)混凝剂,用Al-Ferron逐时络合比色法和^27Al NMR法研究了PASS中铝的形态分布．结果表明,Si／Al摩尔比对PASS形态的影响要小于B值的影响;在一定的B值和Si/Al摩尔比下,Alb成为PASS中铝的优势形态;PASS中Alb和Ferron试剂的反应遵循准一级反应规律,其Kb差异不大．     

The amphipod Hyalella azteca as a biomonitor in field deployment studies for metal mining

Specimens of the amphipod Hyalella azteca were deployed, in June-July 2003, along metal contamination gradients in two rivers affected by metal mining in the Abitibi - James Bay region, northwestern Québec. The amphipods were placed along with natural food items in small, acrylic cages and left in six riverine sites for 17 days. Twelve metals (As, Cu, La, Mn, Ni, Sb, Se, Tl, U, V, Zn, and CrO₄²⁻ modelled by WHAM VI) in transplanted H. azteca varied along metal contamination gradients in a consistent manner, i.e., as a function of metal exposure. Bioaccumulation of As, Cr, La, Ni, Sb, Se, Tl, U and V, as defined by a field BCF, was significantly correlated with their chronic toxicity potential towards the amphipod. We conclude that H. azteca may be a useful field biomonitor for metal mining. In addition, our results suggest that such biomonitoring programs should include less studied elements such as Se in mining effluents.     

The perpetual state of emergency that sacrifices protected areas in a changing climate

A modern challenge for conservation biology is to assess the consequences of policies that adhere to assumptions of stationarity (e.g., historic norms) in an era of global environmental change. Such policies may result in unexpected and surprising levels of mitigation given future climate‐change trajectories, especially as agriculture looks to protected areas to buffer against production losses during periods of environmental extremes. We assessed the potential impact of climate‐change scenarios on the rates at which grasslands enrolled in the Conservation Reserve Program (CRP) are authorized for emergency harvesting (i.e., biomass removal) for agricultural use, which can occur when precipitation for the previous 4 months is below 40% of the normal or historical mean precipitation for that 4‐month period. We developed and analyzed scenarios under the condition that policy will continue to operate under assumptions of stationarity, thereby authorizing emergency biomass harvesting solely as a function of precipitation departure from historic norms. Model projections showed the historical likelihood of authorizing emergency biomass harvesting in any given year in the northern Great Plains was 33.28% based on long‐term weather records. Emergency biomass harvesting became the norm (>50% of years) in the scenario that reflected continued increases in emissions and a decrease in growing‐season precipitation, and areas in the Great Plains with higher historical mean annual rainfall were disproportionately affected and were subject to a greater increase in emergency biomass removal. Emergency biomass harvesting decreased only in the scenario with rapid reductions in emissions. Our scenario‐impact analysis indicated that biomass from lands enrolled in the CRP would be used primarily as a buffer for agriculture in an era of climatic change unless policy guidelines are adapted or climate‐change projections significantly depart from the current consensus.     

固态聚合氯化铝的27Al NMR研究

聚合氯化铝(PAC)是一种水处理混凝剂,可为液态(PAC-L),也可浓缩成固体(PAC-S)、PAC-L在水中稀释时铝的形态的变化已用~(27)Al核磁共振法(NMR)进行了研究。本工作试图用~(27)Al NMR法对PAC-S及其在水中溶解稀释物中铝的形态进行研究,以探讨固化对PAC及其在水中铝的形态的影响。     

Early prenatal diagnosis of the fragile site AT Xq27.3 associated with Martin-Bell syndrome

Early prenatal diagnosis of the fragile X was attempted in 44 pregnancies, including one twin pregnancy at risk of Martin-Bell (MB) syndrome. The sex ratio was 24M:21F. The fragile site was reproducibly demonstrated in cultured chorionic villus (CV) cells in eight male and five female fetuses. Six of the male and three of the female fetuses were terminated. Simultaneous RFLP analysis provided confirmative data with flanking DNA markers in 3 of 13 analysed cases. Recombination and/or non-informativeness at available distal and/or proximal loci were found in nine cases. In one male fetus, discordance between the haplotype and cyto-genetics (fragile-X-negative) suggested the presence of a normal male transmitter, a double meiotic cross-over within the region, or a false-negative cytogenetic diagnosis. However, discordance between prenatal and post-termination/postnatal cytogenetic findings was not observed in this series. The use of excess thymidine for induction of the fragile X in cultured CV cells provided in the majority of cases a safe and rapid method for cytogenetic diagnosis, with options for early induced termination in fragile-X-positive pregnancies, for simultaneous RFLP analysis, and for subsequent second-trimester analysis of fetal blood in complicated cases.