Visual Modflow模型在地下水污染模拟预测中的应用研究

选取中国东北部某地级市地下水源地补给区,研究地下水运动规律及水中所含污染物迁移转化规律,结合气象、水文、地质、水质等资料,在地下水水均衡计算的基础上,应用地下水有限差分软件Visual Modflow建立了地下水水流水质预测模型,并校正模型.提出的建议对研究区地下水多为战略用水,多属风险防控区,其次是需加强地下水环境准入,以生态红线标准管理,以及加快落实工业污染源、垃圾填埋场等污染防治责任.通过模型预测出未来一定时间段内的地下水流及水质变化情况,为当地政府提出地下水污染防治对策和措施提供了理论依据.     

Das motorische Intentionspotential

Autocorrelation of the EEG was used to registrate a potential from the intact human scalp during intended, but not executed movements (dorsalflexion of the right hallux, imaginated in equal time intervals). This "Motor Intention Potential" (MIP) is a possible electrophysiological sign of the otherwise purely introspectively experienced intention of a voluntary movement and the cortex of the frontal lobes is suspected to be its origin. The average maximum amplitude height is 6 microV, and the potential shows a continuous decrease from the frontal to occipital region. The duration of MIP is in the range of seconds. Methodological questions are discussed, and the MIP is differentiated from other event-, movement- and imagination-related potentials. An attempt is made to place the motor intention potential in the context of existing movement theories.     

Das Periphere Sehen — Funktion und Bedeutung

The human retina may be divided into two parts, representing different functional capabilities: the center, i.e., the fovea, and the much greater periphery. Under photopic conditions the fovea has a very high spatial resolution, a high light-difference sensitivity, and a good perception of slow movements. Opposed to this the periphery shows an especially high temporal resolution and a good perception of fast movements. This enables the visual system to detect dangerous objects appearing in the periphery as soon as possible and to induce a detailed analysis in the fovea after triggering a fixational movement.     

典型案例地下水污染模拟预测评估

针对典型案例地下水污染模拟预测评估,可以选取中国东北部某典型工业污染源,应用地下水有限差分软件Visual Modflow,在地下水水均衡计算的基础上,结合气象、地质、水文、水质等资料,建立了典型工业污染源地下水水流水质预测模型.研究了地下水运动规律及水中污染物迁移转化规律,预测出未来两年内的地下水流及水质变化情况,为当地政府提出地下水污染防治对策和措施提供了理论依据.这样可以利用中国东北部某典型工业污染源,为地下水的保护提供保障.     

数值分析三峡库区突发事故污染物运移特性

三峡库区蓄水后水体自净能力降低,突发水污染事故对库区水质的威胁加大.基于对库区水质现状和污染危险源的分析和调查.运用物质迁移扩散理论建立流体动力学模型,应用选择断面的流速模拟值与实测值的对比结果验证模型的精确度,数值模拟了突发水污染事故后物质在水体中的迁移扩散情况,研究事故后污染物在水体中的运动规律;并结合实际情况和具体特点,设定污染物在水中的衰减参数,对采取相关措施后污染物在水体中的消减趋势进行了数值模拟,得到了形象直观的动态可视化显示结果,对应急措施的方法和效果进行了分析和讨论,为事故后相关处理方法和措施的采取及实施方式和地点的选择提供了决策支持,为突发水污染事故的处理处置提供辅助决策工具.     

浅析振动环境中典型电子产品的损伤规律

在分析电子装备结构特点及冲击振动环境影响因素基础上,阐述了电子产品在振动环境中的损伤机理与模式,以某型雷达装备为试验对象,选取该装备某型组合体与电路板进行冲击振动与扫频振动试验,分析了电子产品在振动环境中损伤的一般规律。试验表明:电子产品在振动环境中的损伤不仅与振动类型及幅值有关,也与其自身结构有着密切的关系。     

微囊藻毒素研究进展

蓝藻水华使水的感官性状恶化，水体自净能力降低，其中的蓝绿藻会产生对健康有潜在威胁的微囊藻毒素，是淡水水体中危害最大的一类。就国内外近年来对微囊藻毒素的毒理、危害和流行病学等方面的研究作一综述。     

视觉影响评价技术研究与应用

文章首先对于国内外出现的视觉影响评价与景观影响评价的概念进行了对比分析，提出“视觉影响评价”在功能表述上更为确切，并给出了视觉影响评价的基本概念，然后针对视觉影响评价的特点，介绍了视觉模拟用以预测影响的手段以及评价方法和减缓措施，并通过一具体实例进行了说明，最后针对我国视觉影响评价的现状提出了一些加强和改善的建议。     

Sex identification in female crayfish is bimodal

Sex identification has been studied in several species of crustacean decapods but only seldom was the role of multimodality investigated in a systematic fashion. Here, we analyse the effect of single/combined chemical and visual stimuli on the ability of the crayfish Procambarus clarkii to identify the sex of a conspecific during mating interactions. Our results show that crayfish respond to the offered stimuli depending on their sex. While males rely on olfaction alone for sex identification, females require the combination of olfaction and vision to do so. In the latter, chemical and visual stimuli act as non-redundant signal components that possibly enhance the female ability to discriminate potential mates in the crowded social context experienced during mating period. This is one of the few clear examples in invertebrates of non-redundancy in a bimodal communication system.     

Landscape visualisation and climate change: the potential for influencing perceptions and behaviour

The urgent need to mitigate and adapt to climate change is becoming more widely understood in scientific and policy circles, but public awareness lags behind. The potential of visual communication to accelerate social learning and motivate implementation of the substantial policy, technological, and life-style changes needed, has begun to be recognised. In particular, realistic landscape visualisations may offer special advantages in rapidly advancing peoples’ awareness of climate change and possibly affecting behaviour and policy, by bringing certain possible consequences of climate change home to people in a compelling manner. However, few such applications are yet in use, the theoretical basis for the effectiveness of visualisations in this role has not been clearly established, and there are ethical concerns elicited by adopting a persuasive approach which deliberately engages the emotions with visual imagery. These questions and policy implications are discussed in the context of a theoretical framework on the effects of landscape visualisation on a spectrum of responses to climate change information, drawing in part on evidence from other applications of landscape visualisation. The author concludes that the persuasive use of visualisations, together with other approaches, may be effective, is justified, and could be vital in helping communicate climate change effectively, given ethical standards based on disclosure, drama, and defensibility.     

The plant physical features selected by wildcats as signal posts: an economic approach to fecal marking

The chemical signals of solitary and territorial felid species are essential for their intraspecific communication. We studied the selection of plant substrates during the fecal marking behavior of the European wildcat Felis silvestris from September 2008 to June 2009 in a protected area in Northwest Spain. The aim of the study was to examine the selection of plants as signal posts with respect to their physical characteristics. We hypothesized that wildcats deposit their fecal marks on plants with physical characteristics (e.g., size, species, and visual conspicuousness) that enhance the olfactory and visual effectiveness of the signal. Our results indicate that diameter, plant group, visual conspicuousness, and interaction between the diameter and plant group influence the decision of wildcats to deposit their fecal marks on plants. The wildcats chose plants with greater diameters and greater visual conspicuousness as scent-marking posts. Moreover, the wildcats chose woody and herbaceous plants, and certain plant species were marked more frequently than expected at random. Indeed, our results indicate that the fecal marks were not randomly distributed on the plants: the wildcats chose to place their marks on plants with certain physical characteristics that maximized the detectability of the signal by intruders and potential mates, thus facilitating the spatial distribution of the species.     

镉暴露对文蛤雄性生殖细胞的影响

以文蛤(Meretrix meretrix)为实验材料,采用体外暴露法进行镉染毒,镉离子浓度设置为0、1.5、3、6和12 mg·L-1.染毒5天后解剖取材,测量其精子浓度、运动能力、顶体酶活性和核DNA完整性;目的是从生理、生化和分子生物学角度综合评价镉对文蛤雄性生殖细胞的影响.实验结果表明,文蛤精子浓度、运动能力、顶体酶、DNA完整性均在镉浓度小于成体半致死浓度的情况下,与镉浓度呈现出显著的剂量-效应关系.对镉离子的敏感性分别为:DNA完整性＞精子浓度＞顶体酶活性＞快速运动比例＞运动比例.文蛤雄性生殖细胞的生理、生化指标均可作为重金属镉污染海洋贝类毒性效应的指示物.     

视觉影响评价技术初探

首先简要介绍了国内外开展视觉影响评价的情况和意义 ,提出了视觉影响评价的基本概念、步骤和方法。针对视觉影响评价的特点 ,介绍了 4种视觉模拟用以预测影响的手段。最后针对我国视觉影响评价的现状提出了一些加强和改善建议。     

正十六烷在电场作用下的迁移与微生物降解

研究了砂土中的正十六烷在电动强化微生物作用下的迁移特征和影响因素,揭示利用非均匀电动力学技术修复链烷烃污染土壤的特性。结果表明:非均匀电动力学过程能有效地促进土壤中正十六烷和细菌的迁移,电渗析是其主要作用机理。在1.2V/cm电压梯度下砂土中的正十六烷向阴极迁移速率约为0.7cm/d;电极对污染物、降解菌的迁移作用和电极反应引起的土壤pH变化使得污染物主要在距阳极15cm处被降解,可利用该过程将污染物迁移到规定区域,然后投加高效降解菌进行定点修复。     

长江口污染物运动轨迹模拟

长江口流域污染物排放较多,受地形和水环境过程影响其运动规律极为复杂。为保护近岸海域水质环境,须在洞悉该区域环境水动力基础上开展污染物运动规律的研究。基于ECOMSED三维数值模型和拉格朗日粒子追踪技术,采用单个粒子以及粒子群模拟追踪了长江口的石洞口、竹园、白龙港三大污水排污口区域污染物质的运动轨迹,重点分析了水体表层、中层、底层污染物的运动特性及其影响范围,在此基础上,对该区域水体的排污设置方式提出了参考建议。     

Microspectrophotometric evidence for cone monochromacy in sharks

Sharks are apex predators, and their evolutionary success is in part due to an impressive array of sensory systems, including vision. The eyes of sharks are well developed and function over a wide range of light levels. However, whilst close relatives of the sharks—the rays and chimaeras—are known to have the potential for colour vision, an evolutionary trait thought to provide distinct survival advantages, evidence for colour vision in sharks remains equivocal. Using single-receptor microspectrophotometry, we measured the absorbance spectra of visual pigments located in the retinal photoreceptors of 17 species of shark. We show that, while the spectral tuning of the rod (wavelength of maximum absorbance, λ_max 484–518 nm) and cone (λ_max 532–561 nm) visual pigments varies between species, each shark has only a single long-wavelength-sensitive cone type. This suggests that sharks may be cone monochromats and, therefore, potentially colour blind. Whilst cone monochromacy on land is rare, it may be a common strategy in the marine environment: many aquatic mammals (whales, dolphins and seals) also possess only a single, green-sensitive cone type. It appears that both sharks and marine mammals may have arrived at the same visual design by convergent evolution. The spectral tuning of the rod and cone pigments of sharks is also discussed in relation to their visual ecology.     

A simulation analysis of the migration and transformation of pollutants contained in landfill leachate

A dynamic composite model for a soil-water system that can be used to simulate the movement of leachate from a landfill. The composite model includes nine sub-models that trace water movement and the migration and transformation of five pollutants(organic N, NE4^- ,NO3^- , NO2^-, and Cl^ - ) in saturated and unsaturated soil. The model to simulate the movement of leachate from a landfill in Laogang Town,Shanghai City was used. In this application, the values for the model parameters were oblained by performing a laboratory simulation experimentof water movement and pollutant migration and transformation in soil columns. Soil and leachate obtained from the landfill site and its vicinitywere used in the laboratory experiments. The model was then used to simulate leachate movement and pollutant activity during the ten-year period when the landfill was in operation and in the twenty-year period following its closure. The simulation results revealed that the leachate migrated into the groundwater at the rate of 90-100 meters per year. This model can be applied in the design of future landfills in China for the purpose of assessing and forecasting leachate plumes.     

垃圾填埋场渗滤液水量平衡的实验研究

通过回灌条件下的水量平衡实验,分析了回灌条件下水分运动各个要素(降水、径流、下渗、蒸发)之间的关系。在回灌条件下,土壤蒸发能满足渗滤液的水量平衡,下渗水量通过土壤蒸发作用得以大量削减。土壤水分饱和程度对蒸发量的影响是明显的,土壤水分供给充足时,土壤蒸发按蒸发能力进行,蒸发量大而稳定。     

摆辗机摆头运动学分析和运动轨迹的数值模拟

从摆动辗压机中摆头的结构出发．通过运动学分析给出摆头运动方程，采用数值方法对摆头运动轨迹进行数值模拟，为摆辗机结构设计和摆辗工艺的合理应用提供科学依据。