Optimisation algorithms for spatially constrained forest planning

We compared genetic algorithms, simulated annealing and hill climbing algorithms on spatially constrained, integrated forest planning problems. There has been growing interest in algorithms that mimic natural processes, such as genetic algorithms and simulated annealing. These algorithms use random moves to generate new solutions, and employ a probabilistic acceptance/rejection criterion that allows inferior moves within the search space. Algorithms for a genetic algorithm, simulated annealing, and random hill climbing are formulated and tested on a same-sample forest-planning problem where the adjacency rule is strictly enforced. Each method was randomly started 20 times and allowed to run for 10,000 iterations. All three algorithms identified good solutions (within 3% of the highest found), however, simulated annealing consistently produced superior solutions. Simulated annealing and random hill climbing were approximately 10 times faster than the genetic algorithm because only one solution needs to be modified at each iteration. Performance of simulated annealing was essentially independent of the starting point, giving it an important advantage over random hill climbing. The genetic algorithm was not well suited to the strict adjacency problem because considerable computation time was necessary to repair the damage caused during crossover.     

Application of aerial remote sensing in the study on vegetation in Guangzhou,China

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不同阴极电子受体从生物燃料电池中发电的比较研究

以活性炭阳极双室生物燃料电池为基础,使用葡萄糖(COD为2000mg·L-1)作为底物,比较了铁氰化钾、过氧化氢、重铬酸钾和高锰酸钾分别作为生物燃料电池阴极电子受体时电池的开路电压和功率输出.结果表明,铁氰化钾、过氧化氢和重铬酸钾对应的开路电位分别为0.72V、0.33V和1.13V,均低于高锰酸钾的1.4lV.铁氰化钾和重铬酸钾对应的最大功率密度分别为4788mW·m-3和10951m W·m-3,相比之下高锰酸钾对应的最大功率达到了21912 mW·m-3.除过氧化氢外,3种氧化剂对应的电池内阻没有区别,均在2200Ω左右.当高锰酸钾浓度为200mg·L-1、pH为2.0时,开路电位高达1.44V,阴极电位达到1.38V,pH对电池电压输出的影响比高锰酸钾浓度更为显著.将高锰酸钾用于生物燃料电池从有机废水中发电不但可以极大提高系统的功率输出,还具有十分显著的经济和环境效益.     

高速公路生活区污水处理初探

通过对高速公路生活区污水特点的分析及各种生活污水处理的工艺比较向人们提供一种适合高速公路生活区污水处理的工艺。     

两种管理科学方法在城市化SEA中的应用

城市化和城市发展已经成为世界关注的焦点。正确看待城市化SEA，并将管理科学中的方法结合，从定性到定量综合集成(meta—synthesis)引入城市化SEA进行初步探讨。     

环胶州湾河流入海口CDOM吸收光谱特征

为深入认识河流对胶州湾水体有机碳的贡献,于2016年4月-2017年2月对环胶州湾河流入海口进行双月采样,通过分析水体中DOC（溶解有机碳）和POC（颗粒有机碳）质量浓度及CDOM（有色溶解有机物）的吸收光谱特征,揭示环胶州湾入海口有机碳的分布特征,辨析CDOM的组成和来源,探讨其与主要环境因素的关系.结果表明:①环胶州湾河流入海口DOC和POC质量浓度范围分别为0.98~32.75和0.13~22.40 mg/L,其中李村河口最高,轮渡和大港相对较小.②a（355）（CDOM的吸收系数）变化范围为0.23~16.35 m-1,存在明显的季节性差异,与盐度成反比,其分布与DOC和POC基本一致.③研究区域水体中,表征CDOM分子组成、来源及芳香化程度的S_R[光谱斜率比,S_g（275~295 nm）/S_g（350~400 nm）]和A_{250 nm}/A_{365 nm}存在显著的时空差异.④夏季、秋季CDOM的整体分子量水平高于春季、冬季;轮渡、大港、板桥坊河和娄山河S_R相对较高,CDOM组成趋向于蛋白类或富里酸类物质.⑤轮渡、大港和镰湾河A_{250 nm}/A_{365 nm}相对较高,类腐殖质的芳香化程度较低,受海源控制;其他河口A_{250 nm}/A_{365 nm}相对较低,CDOM以陆源输入为主,其类腐殖质的芳香化程度较高,结构相对稳定而不易降解.⑥CCA（Canonical Correspond Analysis,典范对应分析）结果表明,DOC与CDOM吸收特性存在较好的相关性,河口CDOM主要来自地表径流,温度和DO是影响CDOM时空分布的主要因素.研究显示,CDOM的组成、降解的难易程度与来源密切相关,秋季生物量丰富,水体中腐殖酸所占比例增大,CDOM芳香度较高,不容易被降解.      

Managed grassland alters soil N dynamics and N2O emissions in temperate steppe

Reclamation of degraded grasslands as managed grasslands has been increasingly accelerated in recent years in China. Land use change affects soil nitrogen(N) dynamics and nitrous oxide(N_2O) emissions. However, it remains unclear how large-scale grassland reclamation will impact the grassland ecosystem as a whole. Here, we investigated the effects of the conversion from native to managed grasslands on soil N dynamics and N_2O emissions by field experiments in Hulunber in northern China. Soil(0–10 cm), nitrate(NO_3~-),ammonium(NH_4~+), and microbial N were measured in plots in a temperate steppe(Leymus chinensis grassland) and two managed grasslands(Medicago sativa and Bromus inermis grasslands) in 2011 and 2012. The results showed conversion of L. chinensis grassland to M.sativa or B. inermis grasslands decreased concentrations of NO_3~–-N, but did not change NH_4~–N . Soil microbial N was slightly decreased by the conversion of L. chinensis grassland to M.sativa, but increased by the conversion to B. inermis. The conversion of L. chinensis grassland to M. sativa(i.e., a legume grass) increased N_2O emissions by 26.2%, while the conversion to the B. inermis(i.e., a non-legume grass) reduced N_2O emissions by 33.1%. The conversion from native to managed grasslands caused large created variations in soil NO?3~-+–N and NH_4~–N concentrations. Net N mineralization rates did not change significantly in growing season or vegetation type, but to net nitrification rate. These results provide evidence on how reclamation may impact the grassland ecosystem in terms of N dynamics and N_2O emissions.     

Sorption of tylosin and sulfamethazine on solid humic acid

Tylosin(TYL) and sulfamethazine(SMT) are ionizable and polar antimicrobial compounds,which have seeped into the environment in substantial amounts via fertilizing land with manure or sewage. Sorption of TYL and SMT onto humic acid(HA) may affect their environmental fate. In this study, the sorption of TYL and SMT on HA at different conditions(pH, ionic strength) was investigated. All sorption isotherms fitted well to the Henry and Freundlich models and they were highly nonlinear with values of n between 0.5 and 0.8, which suggested that the HA had high heterogeneity. The sorption of TYL and SMT on HA decreased with increasing p H(2.0–7.5), implying that the primary sorption mechanism could be due to cation exchange interactions between TYL~+/SMT~+ species and the functional groups of HA.Increasing ionic strength resulted in a considerable reduction in the K_d values of TYL and SMT,hinting that interactions between H bonds and π–π EDA might be an important factor in the sorption of TYL and SMT on HA. Results of Fourier transform infrared(FT-IR) and ~13C-nuclear magnetic resonance(NMR) analysis further demonstrated that carboxyl groups and O-alkyl structures in the HA could interact with TYL and SMT via ionic interactions and H bonds,respectively. Overall, this work gives new insights into the mechanisms of sorption of TYL and SMT on HA and hence aids us in assessing the environmental risk of TYL and SMT under diverse conditions.