荔枝叶片与土壤常量元素质量分数年周期变化研究

从１９９７年开始,对荔枝叶片和土壤常量有效养分质量分数、ｐＨ值的年周期变化进行了研究。通过统计学分析,初步探明叶片各元素质量分数季节性变化的模式及其特点,以及土壤有效养分质量分数、ｐＨ值年周期变化的趋势;分析了年周期变化中叶片与土壤分析值之间的相关性。     

围海造陆形成后对生态环境和渔业资源的影响--以天津临港工业区滩涂开发一期工程为例

研究的目的在于利用有关数学模型的研究成果,结合项目区域海洋生态环境的现状,分析围海造陆工程形成后由于项目本身侵占湿地以及周围海域水动力条件的改变对生态环境和渔业资源的影响。分析结果表明,滩涂开发工程对养殖区等生态敏感目标的影响不明显,但对滩涂湿地生态系统有一定程度的影响,表现为占用部分湿地,导致湿地总面积减少,但本地区海河口湿地面积缩小对渤海湾生态环境的影响有待进一步研究。文章从管理与规划角度出发提出滩涂开发过程中的有关建议和要求。     

建筑工程事故分析及预防

从质量和施工安全两个方面分析了建筑工程事故的产生原因,并针对我国建筑业的现状、建筑工程质量事故和施工安全事故产生的原因提出了预防建筑工程质量事故和建筑工程施工安全事故发生的建议。     

多元统计分析在四川退耕还林区土壤肥力评价中的运用

以四川洪雅退耕还林区4种退耕还林模式和农耕地17个土壤肥力指标为例,采用多元统计的主成分分析法对土壤肥力等级进行综合评价. 借助SPSS统计软件得出土壤肥力指标前5个主成分的累计贡献率为84.17%,已足够反映原指标信息. 这5个主成分分别概括为:①土壤有效磷,铵态氮,pH水浸,水解氮,全氮,硝态氮和全磷指标;②土壤全钾、速效钾和缓效钾指标;③土壤总孔隙度、毛管孔隙度和最大持水量指标;④土壤容重,毛管持水量,pH盐浸指标;⑤土壤有机质指标. 借助SPSS统计软件计算主成分因子的综合得分. 结果显示:就各模式土壤上层比较,模式Ⅲ(牛鞭草)上层在综合得分中排名第一. 就各模式土壤下层比较,模式Ⅱ(苦竹+牛鞭草)下层在综合得分中排名第一.      

环境监测数据线性回归分析中回归模型的比较

应用偏重于优化因变量拟合效果的最小二乘回归分析法对环境监测随机数据样本进行数值评估原则上是不可取的。文章以降水无机阴阳离子电荷平衡分析为例,对最小二乘法、压轴回归法和最小正交平方和法的回归分析结果进行了比较。结果表明,压轴回归分析法适合于处理随机数据样本,得到的回归系数b值较大,变量之间的数值变化关系较为密切。     

Reallocating budgets among ongoing and emerging conservation projects

Conserving biodiversity and combating ecological hazards require cost-effective allocation of limited resources among potential management projects. Project priorities, however, can change over time as underlying social-ecological systems progress, novel priorities emerge, and management capabilities evolve. Thus, reallocation of ongoing investments in response to shifting priorities could improve management outcomes and address urgent demands, especially when additional funding is not available immediately. Resource reallocation, however, could incur transaction costs, require additional monitoring and reassessment, and be constrained by ongoing project commitments. Such complexities may prevent managers from considering potentially beneficial reallocation strategies, reducing long-term effectiveness. We propose an iterative project prioritization approach, based on marginal return-on-investment estimation and portfolio optimization, that guides resource reallocation among ongoing and new projects. Using simulation experiments in 2 case studies, we explored how this approach can improve efficacy under varying reallocation constraints, frequencies, costs, and rates of project portfolio change. Periodic budget reallocation could enhance the management of stochastically emerging invasive weeds in Australia and thus reduce the overall risk by up to 50% compared with a static budget. Reallocation frequency and the rate of new weed incursion synergistically increased the conservation gains achieved by allowing unconstrained reallocation. Conversely, budget reallocation would not improve the International Union for Conservation of Nature conservation status of threatened Australian birds due to slow rates of transition among conservation states; extinction risk could increase if portfolio reassessment is costly. Although other project prioritization studies may recommend periodic reassessment and reallocation, our findings revealed conditions when reallocation is valuable and demonstrated a structured approach that can help conservation agencies schedule and implement iterative budget-allocation decisions cost-effectively.     

Social, economic, and ecological impacts of the "Grain for Green" project in China: a preliminary case in Zhangye, Northwest China

This paper provides applications of the integrated assessment (IA) approach in a case study in the Heihe River Basin of Northwest China. Some socio-economic and ecological impact results of forestry land use scenarios are presented in the paper. While seven types of land use scenarios for carbon sequestration purposes were considered for the IA applications, this paper mainly presents impacts of land use scenarios within the Grain for Green (GFG) category [see Yin et al., this volume]. China's national Grain for Green Project was implemented in order to protect and improve ecosystems, while allowing an evolution of agricultural management practices compatible with raising peasants' incomes. Zhangye Prefecture, located in the Heihe River Basin of an arid area in Northwest China, was chosen as the investigation site of the IA case study. Based on fundamental orientation theory, the social sustainability impacts of GFG land use options were assessed. Between 2002 and 2004, the GFG project brought US$23.56 million yuan in net income to the prefecture's peasants. Project implementation resulted in a 1.71 Gg increase in net primary productivity (NPP), as well as a 44.36 Gg rise in net ecosystem productivity (NEP). This suggested that, in Zhangye Prefecture, the Grain for Green Project could enhance the sustainability and stability of the local society, increase peasants' net income, as well as protect and remediate local ecosystems.     

神光Ⅲ激光装置安全管理探讨

神光Ⅲ激光装置是我国在惯性约束聚变研究领域建设的科学工程,具有涉及学科多、指标要求高、建设周期长、建造规模大等特点,其安全管理面临复杂局面。本文首先阐述了神光Ⅲ激光装置在设计、建造、运行维护阶段的安全管理。其次,结合前期工作重点提出了动态危险源辨识、科研人员安全培训、现场安全监管等三方面的问题。最后,探讨了针对上述问题的安全管理对策,提出了三纲四目制危险源辨识、以设计师为核心对象的上岗安全培训、安全监察员制度等针对性措施,为今后国家类似科学工程如何建立一种专业化、本地化的有效安全管理模式提供了借鉴,同时也为该工程下一步推行安全生产标准化建设指明了工作重点。     

基于《施工企业安全生产评价标准》的水利水电施工工程项目重大危险源评价

水利水电施工工程项目重大危险源不同于其他危险化学品等行业重大危险源的评价.施工工程项目的安全性和可靠性既取决于施工工程各单元的危险性,还与施工现场安全管理和施工企业安全生产能力有关.目前,我国尚缺乏水利水电施工工程项目重大危险源的评价标准,为了研究水利水电施工工程项目重大危险源的评价,采用作业条件危险性分析方法,对施工工程的危险性进行评价,然后根据行业标准《施工企业安全生产评价标准》( JGJ/T 77-2010)的取值方法和权重标准对施工企业安全生产综合能力进行评价,使用企业安全生产综合能力评价因子作为管理抵消因子,最终确定施工工程重大危险源.结合某水利水电工程项目的实际,进行了应用分析,结果表明,该方法能比较准确、客观地描述施工类工程项目的重大危险源评价.     

南水北调穿越北京地铁13号线清河桥施工优化分析

以南水北调工程盾构施工穿越北京地铁13号线清河桥工程为背景,采用有限元分析方法,针对不同施工加固措施及行车速度条件下所引起的桥面竖向变形、桥墩竖向变形和地表沉降等问题进行了研究。总结了预加固旋喷桩配比参数、注浆配比参数及行车速度等因素对各结构变形的影响程度。结果表明:水灰比为1.00时的旋喷桩,既能控制结构变形,又具有较高的经济和施工效益;水泥浆与水玻璃浆之比为1.0∶1.0时的注浆参数最优;行车速度控制在50 km/h以下时,能较好地控制结构变形的发展。最后通过对施工过程中各结构的变形进行监测,验证了优化结果的合理性。