在WSN(Wireless Senor Network,无线传感器网络)中的分级路由算法中,如果簇头仅仅能够进行单跳通信或者多跳通信,都会造成网络负载不均衡以及簇头能量消耗过快的问题出现。针对这一问题,文章提出了一种改进的基于LEACH-C(Low Energy Ada...在WSN(Wireless Senor Network,无线传感器网络)中的分级路由算法中,如果簇头仅仅能够进行单跳通信或者多跳通信,都会造成网络负载不均衡以及簇头能量消耗过快的问题出现。针对这一问题,文章提出了一种改进的基于LEACH-C(Low Energy Adaptive Clustering Hierarchy Centralized,低功耗自适应集中分层型)算法的簇间路由(Cluster Routing based on LEACH-C Algorithm,简称CRLA)算法。该算法通过距离阀值来控制簇头是进行单挑通信还是多跳通信。仿真分析表明,CRLA算法能够实现网络负载的均衡以及减少簇头能量的消耗,从而实现网络生存时间的延长。展开更多
The effects of fixation drying conditions on fixation rates and chemical leachab ility were investigated with CCA-C treated red pine (Pinus koraiensis Sieb. )and southern pine specimens at a retention of 6 4 kg·...The effects of fixation drying conditions on fixation rates and chemical leachab ility were investigated with CCA-C treated red pine (Pinus koraiensis Sieb. )and southern pine specimens at a retention of 6 4 kg·m -3 , and under 11 post-treatment schedules ra ng ing from 50～70℃ and 5 different relative humidity conditions. These samples w e re monitored by expressing residual liquid and analyzing it for hexavatent chrom ium content. Samples were subjected to AWPA E11-97 (AWPA 1997) standard leachi n g tests after fixation. Generally, red pine fixed slightly faster than southern pine for most fixation conditions. High temperature, high humidity, fixation co nditions during the fixation/drying schedules resulted in faster fixation and lo wer leaching of chromium and arsenic elements compared to low humidity condition s. Copper leaching showed no significant difference under 11 fixation /drying co nditions for both species. All of the CCA components were leached significantly more in red pine than southern pine. Further work is needed to examine the effec ts of different fixation/drying conditions on leaching from full\|size samples a n d to optimize dry/wet bulb depression for fixation/drying of CCA treated lumber.展开更多
为探究抗生素在土壤中的吸附、解吸及其淋溶迁移行为,采用振荡平衡法和土柱淋溶法分别研究了^(14)C-红霉素在7种不同类型土壤中的吸附、解吸和淋溶特性。吸附试验结果表明,红霉素在7种土壤中的等温吸附-解吸规律满足Freundlich、Langmiu...为探究抗生素在土壤中的吸附、解吸及其淋溶迁移行为,采用振荡平衡法和土柱淋溶法分别研究了^(14)C-红霉素在7种不同类型土壤中的吸附、解吸和淋溶特性。吸附试验结果表明,红霉素在7种土壤中的等温吸附-解吸规律满足Freundlich、Langmiur和线性模型,相关系数R^2为0.9810~0.9999。土壤性质对红霉素的吸附性能有显著影响,7种土壤中吸附常数Kf值依次为S_6>S_3>S_7>S_5>S_2>S_4>S_1。相关性分析表明,Kf值与土壤有机质含量呈正相关(r=0.956,P<0.01),而与土壤pH值、阳离子交换量、粘粒含量无显著相关性。红霉素在7种土壤中的吸附自由能变化均小于40 k J·mol^(-1),表明其在土壤中的吸附机制主要为物理吸附。红霉素在7种土壤中的解吸均存在明显的滞后现象。土柱淋溶试验结果表明,红霉素在7种土壤中淋溶性均较弱,66.86%~92.53%的量集中在0~5 cm表层土壤中。总体上红霉素在土壤S_1、S_2和S_4中的淋溶能力最强,其次为S_3、S_5和S_7,在S_6中最不易淋溶,与吸附试验结果相一致。综合红霉素在土壤中的吸附、解吸和淋溶特性,红霉素在土壤中较难淋溶,使其可能在土壤介质中积累,存在一定的环境污染风险。本研究结果对评估环境安全性具有重要意义。展开更多
文摘在WSN(Wireless Senor Network,无线传感器网络)中的分级路由算法中,如果簇头仅仅能够进行单跳通信或者多跳通信,都会造成网络负载不均衡以及簇头能量消耗过快的问题出现。针对这一问题,文章提出了一种改进的基于LEACH-C(Low Energy Adaptive Clustering Hierarchy Centralized,低功耗自适应集中分层型)算法的簇间路由(Cluster Routing based on LEACH-C Algorithm,简称CRLA)算法。该算法通过距离阀值来控制簇头是进行单挑通信还是多跳通信。仿真分析表明,CRLA算法能够实现网络负载的均衡以及减少簇头能量的消耗,从而实现网络生存时间的延长。
文摘The effects of fixation drying conditions on fixation rates and chemical leachab ility were investigated with CCA-C treated red pine (Pinus koraiensis Sieb. )and southern pine specimens at a retention of 6 4 kg·m -3 , and under 11 post-treatment schedules ra ng ing from 50～70℃ and 5 different relative humidity conditions. These samples w e re monitored by expressing residual liquid and analyzing it for hexavatent chrom ium content. Samples were subjected to AWPA E11-97 (AWPA 1997) standard leachi n g tests after fixation. Generally, red pine fixed slightly faster than southern pine for most fixation conditions. High temperature, high humidity, fixation co nditions during the fixation/drying schedules resulted in faster fixation and lo wer leaching of chromium and arsenic elements compared to low humidity condition s. Copper leaching showed no significant difference under 11 fixation /drying co nditions for both species. All of the CCA components were leached significantly more in red pine than southern pine. Further work is needed to examine the effec ts of different fixation/drying conditions on leaching from full\|size samples a n d to optimize dry/wet bulb depression for fixation/drying of CCA treated lumber.
文摘为探究抗生素在土壤中的吸附、解吸及其淋溶迁移行为,采用振荡平衡法和土柱淋溶法分别研究了^(14)C-红霉素在7种不同类型土壤中的吸附、解吸和淋溶特性。吸附试验结果表明,红霉素在7种土壤中的等温吸附-解吸规律满足Freundlich、Langmiur和线性模型,相关系数R^2为0.9810~0.9999。土壤性质对红霉素的吸附性能有显著影响,7种土壤中吸附常数Kf值依次为S_6>S_3>S_7>S_5>S_2>S_4>S_1。相关性分析表明,Kf值与土壤有机质含量呈正相关(r=0.956,P<0.01),而与土壤pH值、阳离子交换量、粘粒含量无显著相关性。红霉素在7种土壤中的吸附自由能变化均小于40 k J·mol^(-1),表明其在土壤中的吸附机制主要为物理吸附。红霉素在7种土壤中的解吸均存在明显的滞后现象。土柱淋溶试验结果表明,红霉素在7种土壤中淋溶性均较弱,66.86%~92.53%的量集中在0~5 cm表层土壤中。总体上红霉素在土壤S_1、S_2和S_4中的淋溶能力最强,其次为S_3、S_5和S_7,在S_6中最不易淋溶,与吸附试验结果相一致。综合红霉素在土壤中的吸附、解吸和淋溶特性,红霉素在土壤中较难淋溶,使其可能在土壤介质中积累,存在一定的环境污染风险。本研究结果对评估环境安全性具有重要意义。
文摘Fe-N-C材料是目前非常有潜力的一类非贵金属氧还原电极催化剂。本论文分别以导电碳黑(HG-1F)、苯胺、Fe Cl3为碳载体、含氮前驱体、铁前驱体,依次经过聚合、热处理和酸处理获得了多孔Fe-N-C材料。电化学测试结果表明,多孔Fe-N-C材料在0.1 M KOH中催化氧还原反应(ORR)的活性随酸处理时间呈火山型变化,其中酸处理4 h的样品对ORR具有较高的催化活性,促使ORR主要以4电子反应途径进行。
