基于系统动力学的内河危化品运输系统安全管理研究

保障内河危化品运输安全是运输系统安全管理的重要组成部分.为进一步提高运输安全性,根据重大危险源现实危险性评价方法,从危险性和抵消因子的层面出发,引入能见度因素,建立了内河危化品现实危险性系统动力学模型,并建立了相关要素的评分标准.根据系统动力学仿真软件进行现实模拟,得到相关数据,通过分析数据研究各影响因素对运输系统安全性的影响.结果表明,整个交通系统的核心是人员,人员因素对船舶交通运输安全起着重大作用,在人员积极性较高的中期阶段加大工艺、设备安全性的提升,对于提高危化品运输安全有重要作用.加强管理因素可在现有风险基础上降低事故风险,优化和提高运输安全,尤其是在运输后期有重要作用.     

3种常见拉格朗日大气污染扩散模型的理论与应用研究

拉格朗日扩散模型是目前常用的空气质量模型之一,对拉格朗日扩散模型在大气环境质量中的应用与研究的总结有助于进一步提高空气质量模型的预报水平,改善环境空气质量。对当前应用较多的3种拉格朗日扩散模型CALPUFF、HYSPLIT-4和TAPM进行归纳总结,介绍了3种模型的发展历程以及理论基础,概括了不同模型的验证情况与在不同情况下的应用结果,并对3种模型的局限与发展提出了建议。对不同拉格朗日扩散模型的总结研究,可以为环境污染物的预测模拟提供进一步的研究参考方向,并为环境工作者提供一定的参考。     

石羊河流域降水稳定同位素变化的区域差异

为了了解干旱内陆河流域降水稳定同位素变化过程及其影响因素,基于石羊河流域荒漠区、绿洲区和山区8个站点2013年7月至2014年7月,497个降水样品氢氧稳定同位素数据及相应气象数据,研究了石羊河流域降水稳定同位素的时空变化、环境效应以及降水水汽来源.结果显示：石羊河流域局地大气水线斜率和截距表现出夏低冬高的变化趋势;降水稳定同位素表现出夏高冬低的变化趋势,从荒漠区、绿洲区到山区,稳定同位素值随海拔升高而降低,海拔效应为-0.22‰/100m,这是温度效应的另一种体现;流域降水稳定同位素表现出显著的温度效应,温度效应为0.43‰/℃,在天气尺度下受季风水汽和降水淋洗过程的影响表现出降水量效应;流域降水来源主要受西风水汽控制,夏季也会会受到季风水汽影响,冬季也受到极地气团影响.     

Microbial methylation of mercury in the water-level fluctuation zone of the Three Gorges Reservoir, China

正Methylmercury(MeHg)is an organic form of the global pollutant mercury(Hg)which readily accumulates in fish tissue.A majority of Hg methylation is a result of microbial activity and the abundance of inorganic Hg within the water reservoirs(Eckley et al.,2017).Compared to natural lakes and rivers,reservoirs have elevated Hg levels from the decomposition of recently flooded organic material which promote Hg     

载溴石油焦脱除烟气痕量Hg0的动力学机理

采用化学-机械溴化法对废弃物石油焦进行改性,制得的载溴石油焦吸附剂用来脱除燃煤烟气中的痕量Hg⁰.通过比表面积及孔径分析（BET）、X射线衍射（XRD）和X-射线光电子能谱（XPS）对石油焦载溴前后进行表征和分析,发现石油焦中的有机硫促进了溴的负载,且负载方式为化学吸附.通过固定床脱汞试验,并应用4种动力学模型对初始汞浓度梯度和反应温度梯度下的实验数据进行拟合分析,结果表明：温度在150℃时,载溴石油焦的汞吸附效果最优;增加烟气中痕量Hg⁰浓度能提高载溴石油焦的汞吸附速率和单位累积汞吸附量;描述化学吸附的Elovich动力学模型的拟合相关系数达到0.9999以上,说明化学吸附在载溴石油焦脱汞过程中起主导作用.     

Effects of within- and among-patch experiences on the patch-leaving decision rules in an insect parasitoid

The present study aimed to address how an insect parasitoid makes patch-departure decisions from various types of host patches and how previous patch experiences in the environment modify this decision-making process. Experiments were done with the parasitic wasp Aphidius rhopalosiphi attacking the grain aphid Sitobion avenae. In the experiments, wasps were observed in a laboratory environment containing several patches of various host densities, and behavioural records were analysed using a Coxs proportional hazards model. Consideration of the effect of the within-patch experience gave a classic pattern of patch-leaving decision rules in parasitoids: A. rhopalosiphi used local information on host quality (i.e. numbers of ovipositions or rejections) and availability (i.e. patch density) to determine departure decision. However, consideration of previous patch experiences provided evidence that these departure rules are fundamentally dynamic, responding to the physiological state of the animal and the information it has about its environment. Results showed that A. rhopalosiphi decreased its tendency to leave the visited patch after an oviposition. However, when a female has already laid several other eggs in the environment, such an incremental mechanism gradually switched to a decremental one. Hence, A. rhopalosiphi responded to egg-load depletion by leaving the visited patches sooner and by depositing a smaller number of eggs in those patches, which probably led to a decreased level of superparasitism. Results also indicated that previous experiences enabled wasps to estimate spatial host distribution and then to adjust their behavioural decisions accordingly. Thus, A. rhopalosiphi was shown to adjust its patch residence time according to the quality and the number of the patches previously visited. These proximate mechanistic rules adopted by A. rhopalosiphi females are discussed in the context of general predictions from optimality models.Communicated by D. Gwynne     

Agent based simulation of a small catchment water management in northern Thailand: Description of the CATCHSCAPE model

Due to mounting human pressure, stakeholders in northern Thailand are facing crucial natural resources management (NRM) issues. Among others, the impact of upstream irrigation management on downstream agricultural viability is a growing source of conflict, which often has both biophysical and social origins. As multiple rural stakeholders are involved, appropriate solutions should only emerge from negotiation. CATCHSCAPE is a Multi-Agent System (MAS) that enables us to simulate the whole catchment features as well as farmer’s individual decisions. The biophysical modules simulate the hydrological system with its distributed water balance, irrigation scheme management and crop and vegetation dynamics. The social dynamics are described as a set of resource management processes (water, land, cash, labour force). Water management is described according to the actual different levels of control (individual, scheme and catchment). Moreover, the model’s architecture is presented in a way that emphasises the transparency of the rules and methods implemented. Finally, one simulated scenario is described along with its main results, according to different viewpoints (economy, landscape, water management).     

棉花VA菌根的形成与土壤几丁质酶活相关性的研究

盆栽条件下，对棉花ＶＡ菌根的形成与根区土壤中几丁质酶活的相关性及其动态变化的研究结果表明．接种ＶＡ菌根真菌Ｇｌｏｍｕｓｍｏｓｓｅａｅ形成的菌根可促进解几丁质微生物的增殖，并能诱导出较高的土壤几丁质酶活性．酶活增长与菌很感染率成正相关；接种ＶＡ菌根真菌的处理与未接种对照比较，差异显著或极显著．