海洋环境中光合色素分析方法研究与应用进展

根据国内外的文献,综述了海洋环境中光合色素分析方法的发展状况,指出了其分析方法在发展过程中创新的主要方面,并对光合色素分析在赤潮监测、藻类的化学分类及生物碳生物量和矿物质通量方面的应用进行了展望。     

改性氢氧化镁制备及其去除地下水中Cr3+性能研究

氢氧化镁作为一种可缓慢释放OH-的碱,能使多数重金属离子转换为沉淀,而且不会引起太大的pH变化.但氢氧化镁难溶于水,在含水层中的迁移能力很差.若要用于地下水重金属污染修复,需要对氢氧化镁进行改性.因此,本文利用表面活性剂对氢氧化镁粉末进行改性,合成了氢氧化镁胶体,并对改性氢氧化镁的稳定性、粒度及其对Cr3+的稳定化效果进行了分析.结果表明,复配表面活性剂改性的氢氧化镁悬浮液稳定性好,粒径小,0.6~8.4μm的颗粒占82.41%.利用改性氢氧化镁对Cr3+污染地下水进行处理,其对Cr3+的去除机理主要为沉淀反应,氢氧化镁和Cr3+反应的质量比约为1.333∶1,氢氧化镁和初始Cr3+浓度对Cr3+的去除效果都有较大的影响.     

Myrothecium verrucaria NF-08产漆酶条件的响应面法优化及粗酶染料脱色研究

以半知菌属疣孢漆斑菌Myrothecium verrucaria NF-08为供试菌,采用响应面方法优化菌株产漆酶条件,并以其漆酶粗酶进行3种结构类型6种染料的脱色试验,考察了粗酶浓度、温度和p H值对脱色率的影响.两水平析因设计、中心组合设计和验证试验结果表明:葡萄糖浓度为15.4 g·L~(-1)、蛋白胨浓度为43.3 g·L~(-1)和培养基初始p H值为6.68时,漆酶活性达到最大值(25.58±1.60)U·m L~(-1),是单因素试验(16.82 U·m L~(-1))的1.52倍,提高了52.1%.以上述发酵条件获得的M.verrucaria NF-08漆酶粗酶对3种结构类型染料均有脱色效果,排序为偶氮类优于芳甲烷类优于蒽醌类.脱色率随粗酶浓度增大(2~8 U·m L~(-1))、反应温度升高(15~35℃)而上升,随p H值上升(4~10)而下降.粗酶浓度为5 U·m L~(-1),反应温度为25℃,p H值为4时,偶氮类染料铬黑T和芳甲烷类染料碱性品红即可几乎完全脱色,脱色率分别为99.2%和94.6%.     

Effect of vegetation type on throughfall deposition and seepage flux

This paper compares different vegetation types (coniferous and deciduous forest, grassed and pure heathland) in terms of input (throughfall deposition) and output (seepage flux) in a region with intermediate nitrogen load (+/-20kg Nha(-1)y(-1) via bulk precipitation) in comparable conditions in north Belgium. Coniferous forest (two plots Pinus sylvestris and two plots Pinus nigra) received significantly higher nitrogen and sulphur throughfall deposition than deciduous forest and heathland. Grassed and pure heathland had significantly highest throughfall quantities of Ca(2+) and Mg(2+), respectively. The observed differences in throughfall deposition between the different vegetation types were not univocally reflected in the ion seepage flux. Considerable seepage fluxes of NO(3)(-), SO(4)(2-), Ca(2+) and Al(III) were only found under the P. nigra plots. We discuss our hypothesis that the P. nigra forests already evolved to a situation of N saturation, while the other vegetation types did not.     

Modeling the decline of labor-sharing in the semi-desert region of Chile

Regional Environmental Change - The rapid environmental changes currently underway in many dry regions of the world, and the deep uncertainty about their consequences, underscore a critical...     

A Generic Bio-Economic Farm Model for Environmental and Economic Assessment of Agricultural Systems

Bio-economic farm models are tools to evaluate ex-post or to assess ex-ante the impact of policy and technology change on agriculture, economics and environment. Recently, various BEFMs have been developed, often for one purpose or location, but hardly any of these models are re-used later for other purposes or locations. The Farm System Simulator (FSSIM) provides a generic framework enabling the application of BEFMs under various situations and for different purposes (generating supply response functions and detailed regional or farm type assessments). FSSIM is set up as a component-based framework with components representing farmer objectives, risk, calibration, policies, current activities, alternative activities and different types of activities (e.g., annual and perennial cropping and livestock). The generic nature of FSSIM is evaluated using five criteria by examining its applications. FSSIM has been applied for different climate zones and soil types (criterion 1) and to a range of different farm types (criterion 2) with different specializations, intensities and sizes. In most applications FSSIM has been used to assess the effects of policy changes and in two applications to assess the impact of technological innovations (criterion 3). In the various applications, different data sources, level of detail (e.g., criterion 4) and model configurations have been used. FSSIM has been linked to an economic and several biophysical models (criterion 5). The model is available for applications to other conditions and research issues, and it is open to be further tested and to be extended with new components, indicators or linkages to other models.     

330kV输电线路不落导线更换ZM塔施工技术

为了解决输电线路改造施工时影响被跨越物正常运行的难题,在组立铁塔过程中,采用了内悬浮提升抱杆,逐步抬高中相导线,保持导线不落地施工方法,对330 kV大-固线路跨越福-银高速公路段进行改造。应用结果表明:利用2根铝合金薄壁抱杆不落线对ZM铁塔加高的施工方法,操作简单,安全可靠,大大地节约了施工费用,可在类似改造工程中推广使用。     

Aggregation and ecotoxicity of CeO₂ nanoparticles in synthetic and natural waters with variable pH, organic matter concentration and ionic strength

The influence of pH (6.0-9.0), natural organic matter (NOM) (0-10 mg C/L) and ionic strength (IS) (1.7-40 mM) on 14 nm CeO₂ NP aggregation and ecotoxicity towards the alga Pseudokirchneriella subcapitata was assessed following a central composite design. Mean NP aggregate sizes ranged between 200 and 10000 nm. Increasing pH and IS enhanced aggregation, while increasing NOM decreased mean aggregate sizes. The 48 h-E_rC20s ranged between 4.7 and 395.8 mg CeO₂/L. An equation for predicting the 48 h-E_rC20 (48 h-E_rC20 = −1626.4 × (pH) + 109.45 × (pH)² + 116.49 × ([NOM]) − 14.317 × (pH) × ([NOM]) + 6007.2) was developed. In a validation study with natural waters the predicted 48 h-E_rC20 was a factor 1.08-2.57 lower compared to the experimental values.