Modeling Nutrient Export From Coastal California Watersheds

Nitrate and phosphate export coefficient models were developed for coastal watersheds along the Santa Barbara Channel in central California. One approach was based on measurements of nutrient fluxes in streams from specific land use classes and included a watershed response function that scaled export up or down depending on antecedent moisture conditions. The second approach for nutrient export coefficient modeling used anthropogenic nutrient loading for land use classes and atmospheric nutrient deposition to model export. In an application of the first approach to one watershed, the nitrate and phosphate models were within 20% of measured values for most storms. When applied to another year, both nitrate and phosphate models generally performed adequately with annual, storm‐flow, and base‐flow values within 20% of measured nutrient loadings. Less satisfactory results were found when applied to neighboring watersheds with difference percentages of land use and hydrologic conditions. Application of the second approach was less successful than the first approach.     

Moving beyond “mitigation and adaptation”: examining climate change responses in New Zealand

Despite the apparent failure of international negotiations and renewed criticism of the accuracy of climate science, responses to climate change continue in households, cities, fields, and meeting rooms. Notions of “doing something about”, or “taking action on” or “mitigating and adapting” to climate change inform practices of carbon trading, restoring native forests, constructing wind turbines, insulating houses, using energy efficient light bulbs, and lobbying politicians for more or less of these actions. These expressions of agency in relation to climate change provide the focus of our enquiry. We found that relationships or social networks linked through local government are building capabilities to respond to climate change. However, the framework of “mitigation–adaptation” will need to be supplemented by a more diverse suite of mental models for making sense of climate change. Use of appropriate languages, cultural reference points, and metaphors embedded in diverse histories of climates and change will assist actors in their networked climate change responses.     

论高新技术产业开发区的生态化发展

高新技术产业开发区(简称高新区)是以高技术成果产业化、产业集聚化、集聚生态化为目标建立起来的特定经济区域。生态化高科技园区将是高新区发展的第三代工业园区的主要发展模式。高科技产业对环境的污染具有与传统产业不同的特点，决定了高科技园区的生态化发展具有自身的规律性，需要通过对现有企业进行生态化改造，应用ISO14000标准建立环境管理体系和重构环境法规的绿色导向机制等措施来保证生态化的实现。     

Nb、Ti低合金高强度冷轧薄板退火工艺对机械性能的影响

采用硬度法测得Nb、Ti低合金高强度冷轧薄板的再结晶温度为 6 0 0℃。再结晶温度以下退火时 ,钢的屈服强度随温度和时间的增加而降低 ,延伸率则增大 ;再结晶温度以上退火时 ,钢的屈服强度及延伸率变化不明显。实验提出合理选择热轧钢坯的强度 ,可避免不必要地增大冷轧机的负荷。     

Modeling Opportunity Costs of Conservation in Transitional Landscapes

Abstract:  Conservation scientists recognize the urgency of incorporating opportunity costs into conservation planning. Despite this, applications to date have been limited, perhaps partly because of the difficulty in determining costs in regions with limited data on land prices and ownership. We present methods for estimating opportunity costs of land preservation in landscapes or ecoregions that are a changing mix of agriculture and natural habitat. Our approach derives from the literature on estimating land values as opportunity costs of alternate land uses and takes advantage of general availability of necessary data, even in relatively data-poor regions. The methods integrate probabilities of habitat conversion with region-wide estimates of economic benefits from agricultural land uses and estimate land values with a discount rate to convert annual values into net present values. We applied our method in a landscape undergoing agricultural conversion in Paraguay. Our model of opportunity costs predicted an independent data set of land values and was consistent with implicit discount rates of 15–25%. Model-generated land values were strongly correlated with actual land values even after correcting for the effect of property size and proportion of property that was forested. We used the model to produce a map of opportunity costs and to estimate the costs of conserving forest within two proposed corridors in the landscape. This method can be applied to conservation planning in situations where natural habitat is currently being converted to market-oriented land uses. Incorporating not only biological attributes but also socioeconomic data can help in the design of efficient networks of protected areas that represent biodiversity at minimum costs.     

特殊环境下清障爆破方法研究

分析了地下军事设施战损抢修清障爆破的环境特点,在分析多种影响因素的基础上确定了高能燃烧剂爆破和聚能切割爆破2种清障方法,并介绍了各自的作用原理和基本设计。爆破试验结果表明,高能燃烧剂爆破和聚能切割爆破在地下军事设施战损抢修清障爆破中的应用是可行的。     

水环境中天然溶解有机质分子量的研究现状及意义

溶解有机质存在于所有的水环境中,它是组成不均匀、结构复杂和分子量分布很宽的有机化合物混合体。本文综述了测量溶解有机质分子量的主要方法,各种方法的原理和优缺点,其中详细介绍了高效体积排阻色谱法的原理,平均分子量和分散系数的计算,以及分子量的校正;同时介绍了可能影响分子量分布的主要地球化学因素,以及天然水中溶解有机质的分子量分布的特征。     

石墨炉AAS法分析冬青科苦丁茶树系统中镉及其分布

采集海南大学苦丁茶种质资源库中6种冬青科(Ilex)苦丁茶树的根、茎、叶及对应土壤样品,通过试验研究,建立了高压密封消解-石墨炉原子吸收光谱法测定样品中镉的方法。对植物样和土壤样分别采用硝酸-双氧水和硝酸-高氯酸-氢氟酸混酸体系进行消解。以磷酸二氢铵作为基体改进剂,并开启氘灯校正背景,在优化的工作条件下测定样品中镉。该方法的检出限为0.300ng/mL,用于实验样品中镉的测定,其相对标准偏差RSD5%,加标回收率介于94%～108%之间。用该方法对茶叶(GBW10016)和土壤(GBW-07407)标准参考物中镉进行了测定,测定结果与标准值相符合,相对误差小于7%。冬青科苦丁茶树及其土壤中镉的分布具有特征性,主要表现为:土壤茶树,根际土壤非根际土壤,吸收根主根或茎,嫩叶老叶枯叶。     

给水系统中卡马西平含量测定方法的研究

文章用固相萃取与高效液相色谱结合的方法测定给水系统中痕量卡马西平的含量。考察了C18小柱的最佳洗脱条件,并且根据出峰时间选择了最佳的色谱条件:流动相为水(用磷酸调节pH至4)和甲醇(40∶60,V/V),温度为25℃,流速为1.0mL/min,检测波长为285nm。卡马西平浓度在0.2～2mg/L范围内线性关系良好,回归方程y=81.53258x-7.19487,加标回收率平均值为94.3%,RSD为2.7%(n=7)。用该方法测定实际水源水和自来水厂中间工段出水,简单易操作,结果准确。     

基于GaN技术的大功率T/R组件可靠性设计与分析

结合T/R组件的工作原理,对影响大功率T/R组件可靠性的关键技术进行了设计与分析。通过与现有的基于GaAs技术的T/R组件设计电路对比分析,阐述了基于Ga N技术的大功率、高可靠性T/R组件的电路设计方法。