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181.
人为土壤形成过程及其在现代土壤学上的意义   总被引:17,自引:0,他引:17  
龚子同  张甘霖 《生态环境》2003,12(2):184-191
随着工业的发展、人口的增加和耕地的减少,特别是工业革命以来,人为作用对土壤形成的影响越来越大。在此过程中,人们培育了人为土,也出现了土壤退化。人为作用重要性的确认扩大了土壤学的视野,土壤不仅是独立的“历史自然体”,人为土还是劳动的产物;土壤不仅是“植物养料的储藏库”,还应是污染物的缓冲带的过滤器。因此,建议用“六大成土因素”代替五大成土因素;用“人地圈”或“智慧土壤圈”来充实“土壤圈”。  相似文献   
182.
It has been proposed that voluntary urban climate programmes overcome shortfalls in mandatory, top-down, state-led government interventions to address climate change risks. Such programmes seek commitments from households and firms to improve their environmental sustainability, but do not have the force of law. City governments are actively developing and implementing such programmes, seeking improved and accelerated urban climate action. There is little evidence, however, of whether their involvement positively affects voluntary programme performance. This article presents qualitative comparative analysis (QCA) of 26 voluntary programmes from Australia, the Netherlands and the US, seeking to understand whether, and if so how, city governments affect the performance of voluntary urban climate programmes. The results will help to inform city governments about the roles they may play in urban climate governance.  相似文献   
183.
为了对比Novec 1230(全氟己酮)感温自启动灭火管系统与R236fa(六氟丙烷)感温自启动灭火管系统的灭火效率,采用火灾实体试验的方法,分析了不充压,0.88,1.81 MPa下2系统的灭火时间、破裂动作温度及降温冷却效果。研究结果表明:2种灭火管系统都成功灭火,且 R236fa灭火管系统灭火时间更短;2种灭火管系统的破裂动作温度均在80 ℃以上;不充压和0.88 MPa时,2种灭火管系统降温冷却效果相差不大,但充压1.81 MPa时Novec 1230灭火管系统对环境温度的降温冷却作用更强。  相似文献   
184.
Scholars across all disciplines have long been interested in how knowledge moves within and beyond their community of peers. Rapid environmental changes and calls for sustainable management practices mean the best knowledge possible is needed to inform decisions, policies, and practices to protect biodiversity and sustainably manage vulnerable natural resources. Although the conservation literature on knowledge exchange (KE) and knowledge mobilization (KM) has grown in recent years, much of it is based on context‐specific case studies. This presents a challenge for learning cumulative lessons from KE and KM research and thus effectively using knowledge in conservation and natural resources management. Although continued research on the gap between knowledge and action is valuable, overarching conceptual frameworks are now needed to enable summaries and comparisons across diverse KE‐KM research. We propose a knowledge‐action framework that provides a conceptual roadmap for future research and practice in KE/KM with the aim of synthesizing lessons learned from contextual case studies and guiding the development and testing of hypotheses in this domain. Our knowledge‐action framework has 3 elements that occur at multiple levels and scales: knowledge production (e.g., academia and government), knowledge mediation (e.g., knowledge networks, actors, relational dimension, and contextual dimension), and knowledge‐based action (e.g., instrumental, symbolic, and conceptual). The framework integrates concepts from the sociology of science in particular, and serves as a guide to further comprehensive understanding of knowledge exchange and mobilization in conservation and sustainable natural resource management.  相似文献   
185.
简述了苍山MS5.2地震的基本概况,分析了苍山52级地震构造背景,据这次地震的余震空间分布、等震线长轴、震源机制解、地震活动条带和地质资料分析认为北西向的苍山 新泰断裂和北东向的荣成 临沂断裂可能是苍山52级地震的地震断层。在1985年6月以前,鲁南地区的地震活动呈随机分布,1985年6月以后ML≥3.0地震主要集中在新泰 苍山 莒县之间的三角地带,来回迁移;1974年以后沿苍山 尼山断裂的ML≥3.0地震都发生在52级地震震中附近,说明在苍山 尼山断裂与沂沭断裂带交汇区西侧较长时间的能量积蓄。苍山52级地震前最后发生的两个ML≥2.0地震与苍山52级地震震中形成沿地震断层的临震小震活动条带。  相似文献   
186.
绿色旅游产业发展模式与运行机制   总被引:10,自引:0,他引:10  
通过介绍国外绿色旅游产业发展的指导方针及非政府组织的行为.结合苏格兰酿酒工业旅游与北京蟹岛生态农业旅游中发展绿色旅游的经验总结.分别提炼出绿色工业旅游的运作模式和绿色农业旅游的发展模式。在此基础上.提出要通过构建由观念、牡会经济体制与科学技术三个层次形成的保障体系.来保证绿色旅游经济的正常运转。最后.从绿色旅游产业地域与行业选择、绿色保障制度体系建立、赢利机制构造和绿色旅游消费者培育等四个方面提出了我国绿色旅游产业发展的行动纲领。  相似文献   
187.
汞和两种农药复合污染对土壤转化酶活性的影响   总被引:7,自引:0,他引:7       下载免费PDF全文
通过模拟方法研究了豆磺隆,呋喃丹2种农药与重金属汞(Hg)单一及复合污染对草甸棕壤和黑土4个土壤转化酶活性的影响.结果显示,在试验浓度范围内,土壤添加豆磺隆和呋喃丹后,转化酶变化幅度分别为-12%~7%和-6%~7%,表明2种农药对土壤转化酶的毒性较小;Hg对转化酶最大抑制率为22%~35%,二者之间呈显著的对数负相关关系,表明Hg对转化酶的毒性较大,转化酶在一定程度上可作为Hg污染的监测指标,通过对数方程计算出4个土样的生态剂量(ED50)分别为76.68,727.49,236.52,316.59mg/kg;Hg和2种农药之间普遍存在交互作用,豆磺隆与Hg复合污染引起土壤转化酶最大净变化量(△I)为对照的-12%~15%,呋喃丹和Hg为-25%~-6%,有机质对复合污染产生的毒性有明显的缓冲作用.  相似文献   
188.
Abstract

A formulation containing the biopesticide azadirachtin‐A (AZ‐A), extracted from the seeds of neem tree, Azadirachta indica A. Juss, was applied (10 μg/mL) in a nutrient solution (200 mL) to the roots of young spruce trees [Picea glauca (Moench) Voss]. The uptake, translocation, persistence and dissipation of AZ‐A in spruce were studied. The insecticide was taken up by the root system, translocated via xylem vessels and accumulated in the photosynthate sinks (areas of new growth, especially shoots), confirming that AZ‐A is systemic. The peak AZ‐A concentrations (μg/g, fresh weight) in the shoots (5.16 ± 0.73) and needles (2.56 ± 0.31) occurred at 8 and 15 d after treatment, respectively. The AZ‐A concentrations in bark and wood during this period were very low, however they were high in the root samples. The dissipation of AZ‐A from the shoots was rapid compared to other matrices. The initial (0‐d) and final (20‐d) AZ‐A concentrations (μg/mL) in the nutrient solution were 8.99 ± 1.24 and 3.24 + 0.55, respectively. The dissipation of AZ‐A in the nutrient solution followed first‐order kinetics. Dissipation half‐life (DT50) and rate constant (C), calculated from the nonlinear regression equation (Y = 8.400 e‐00544t), were 12.74 d and 0.0544, respectively. Usefulness of AZ‐A as a systemic insecticide in forest insect control programs is discussed.  相似文献   
189.
For a community to manage hazards successfully, those who are responsible for planning and implementing responses to a disaster threat situation must understand the social and economic realities of populations at risk. A random sample survey of residents in the vicinity of a US Army chemical weapons storage depot in Alabama confirms that those in the lowest quartile of household income (i.e., less than US $25,000 in 1999) differ in important ways from the rest of the sample. Using economic status as a grouping variable resultedin identifying a concentration of individuals with special needs. This group differed significantly from the remainder of the sample as to demographic and attitudinal characteristics, hazard knowledge and concerns, emergency preparedness, and emergency decision-making and their likelihood of taking protective actions. Respondents in the lowest income quartile reported greater restrictions in physical abilities, fewer community contacts, a heightened concern about area hazards, and limited resources for taking preparedness and response actions.  相似文献   
190.
从事故统计分析结果表明,90%以上的事故是由操作者违章作业造成的。因而提出了安全预案预控活动的有效方法,并介绍了实现这一方法的阶段及效果。  相似文献   
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