网络打印机概念及应用

随着计算机局域网的普遍建立,网络打印机因其既可以提高设备利用率,又可以节省经 费开支也逐步普及。本文对网络打印机的基本知识和操作技巧以及注意事项进行了初步介绍。     

油库池火灾模型的数值模拟

考虑到池火模型在有风状态下视角系数计算的复杂性,运用MATLAB强大的计算和绘图功能,以及可视化GUIDE工具箱,进行了池火灾模型的数值模拟界面化,实现了计算模型的参数和绘制热通量分布图等功能.操作界面简单方便,计算和绘图效率和准确率高.同时避免了命令流方式带来的改变一个参数要重新执行命令和输入的弊端.     

土壤种子库植物种类组成与土壤采集地植被的关系

土壤种子库作为区域自然植被恢复的途径之一,在实际应用之前有许多课题需要研究,土壤种子库出芽植物组成与土壤采集地自然植被的关系就是一个需要弄清的问题。文章从土壤种子库的生态学意义出发,首次对森林表土作为城市自然植被恢复绿化手段的可能性进行了探讨。试验材料取自日本大阪府箕面市大阪国际文化公园都市建设地,选取面积为20m×20m的栓皮栎Quercusvariabilis群落,采集林下5cm厚森林表土;试验场地设在大阪府枚方市山田池公园的一隅荒地,共设置4个试验区,每个试验区7个试验处理,计28个试验小区。研究结果表明:土壤种子库植物种类组成与表土采集地的植被关联性较低,但与种子散布型关系密切;表土的不同铺撒厚度在木本植物出现的种类、出芽个体数、生存个体数等方面都表现出明显的差异性。     

Allocation of nitrogen and carbon in an estuarine salt marsh in Portugal

Above and below-ground biomass and nitrogen and carbon composition ofSpartina maritima, Halimione portulacoides andArthrocnemum perenne, dominating species in plant communities of the lower, middle and higher salt marsh, respectively, were compared in an estuarine salt marsh in Portugal. Plant and soil nitrogen and carbon pools were estimated. For all three species root biomass was significantly higher (70–92% of total biomass) than above-ground biomass. The percentage of root biomass was related to the location of the plants in the marsh: higher values were found in plants growing in the lower salt marsh where the sediment was more unstable and subject to tidal action, which stresses the role of the roots as an anchor. For all three species nitrogen concentrations were highest in leaves, reflecting the photosynthetic role of the tissue. For carbon higher concentrations were found in the stems, with the exception ofS. maritima. In general, lower nitrogen concentrations were found in summer, which can be explained by dilution processes due to plant growth. For both nitrogen and carbon, higher concentrations were found in the soil surface layers. Higher soil nitrogen and carbon levels were associated with higher organic matter contents. Most of the nitrogen in the salt marsh occurred in the sediments (0–40 cm) and only ca. 5.7–13.3% of the total was found in the plants. The greater portion (76.5%–86%) of carbon was found in the sediment.     

Carbon dioxide release due to change in land usein China mainland

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水稻籽实中蛋白质-Cd、Pb结合体及其稳定性

通过凝脱层析方法，对水稻籽实中的蛋白质－Cd,Pb结合形态特征及其稳定性进行了研究。结果表明；水稻籽实TrisHCl提取液经SephadexG-75分 离，洗脱液得到3个紫外吸收峰，在第1、3峰处出现了Cd、Pb浓度峰，其蛋白质－Cd、Pb结合体的表观分子量为54.5KD和5.5KD。在蒸煮加热处理后，水稻籽实中蛋白质－Cd、Pb结合体发生变性，使分子量为54.5KD的蛋白质－Cd,Pb结合体完全破坏，分子量为5.5KD的结合体也部分地被破坏，与蛋白质结合的Cd ,Pb被释放出来。胃蛋白酶和胰蛋白酶消化处理后，也能够破坏蛋白质－Cd,Pb结合体的形态，洗脱液中Cd,Pb的浓度分布也发生了变化，在第1、3紫外吸收峰处的Cd、Pb浓度也明显降低。另外，在第3峰以后的洗脱液中也检测到Cd、Pb的浓度。     

转基因植物入侵性评价指标初探

从生态学 (种子水平和成体水平 )和生理生化 (酶表达、蛋白检测、光合能力等 )层次 ,探讨转基因植物 (GMP)可能形成入侵性的一些特性 ,尝试建立GMP入侵性的评价指标体系 ,为进行转基因植物的安全性评价提供借鉴。     

烃类流体火灾伤害破坏作用定量分析

对烃类流体火灾的伤害破坏作用进行正确的定量分析是开展重大消防目标火灾风险评估工作的基础。针对烃类流体火灾伤害破坏作用定量分析中存在的问题,系统论述烃类流体火灾伤害破坏作用的定量分析方法,分析并讨论火球、池火、喷射火和蒸气云火灾等不同火灾形式的热辐射通量计算模型及其前提条件,对不同热辐射伤害破坏作用准则及伤害概率模型的适用条件和模型基础进行了论述。     

Birds as Suppliers of Seed Dispersal in Temperate Ecosystems: Conservation Guidelines from Real‐World Landscapes

Abstract: Seed dispersal by animals is considered a pivotal ecosystem function that drives plant‐community dynamics in natural habitats and vegetation recovery in human‐altered landscapes. Nevertheless, there is a lack of suitable ecological knowledge to develop basic conservation and management guidelines for this ecosystem service. Essential questions, such as how well the abundance of frugivorous animals predicts seeding function in different ecosystems and how anthropogenic landscape heterogeneity conditions the role of dispersers, remain poorly answered. In three temperate ecosystems, we studied seed dispersal by frugivorous birds in landscape mosaics shaped by human disturbance. By applying a standardized design across systems, we related the frequency of occurrence of bird‐dispersed seeds throughout the landscape to the abundance of birds, the habitat features, and the abundance of fleshy fruits. Abundance of frugivorous birds in itself predicted the occurrence of dispersed seeds throughout the landscape in all ecosystems studied. Even those landscape patches impoverished due to anthropogenic disturbance received some dispersed seeds when visited intensively by birds. Nonetheless, human‐caused landscape degradation largely affected seed‐deposition patterns by decreasing cover of woody vegetation or availability of fruit resources that attracted birds and promoted seed dispersal. The relative role of woody cover and fruit availability in seed dispersal by birds differed among ecosystems. Our results suggest that to manage seed dispersal for temperate ecosystem preservation or restoration one should consider abundance of frugivorous birds as a surrogate of landscape‐scale seed dispersal and an indicator of patch quality for the dispersal function; woody cover and fruit resource availability as key landscape features that drive seedfall patterns; and birds as mobile links that connect landscape patches of different degrees of degradation and habitat quality via seed deposition.