京—秦地区的森林资源及其发展潜力

本文是“京津唐地区(包括秦皇岛市)国土卫星像片在森林资源调查中的应用研究结果的一部分,统计分析了各类森林资源的分布面积和主要特点,并指出其发展潜力,全区现有森林面积计约61.6×10~4 ha,覆盖率约11％,宜林地面积约86.2×10~4 ha,覆盖率约15.4％。主要分布于山地。从发展潜力看,可以增加森林覆盖率10％以上,可能提高立木蓄积量和果树产量4—5倍。     

Bio-char Sequestration in Terrestrial Ecosystems – A Review

The application of bio-char (charcoal or biomass-derived black carbon (C)) to soil is proposed as a novel approach to establish a significant, long-term, sink for atmospheric carbon dioxide in terrestrial ecosystems. Apart from positive effects in both reducing emissions and increasing the sequestration of greenhouse gases, the production of bio-char and its application to soil will deliver immediate benefits through improved soil fertility and increased crop production. Conversion of biomass C to bio-char C leads to sequestration of about 50% of the initial C compared to the low amounts retained after burning (3%) and biological decomposition (< 10–20% after 5–10 years), therefore yielding more stable soil C than burning or direct land application of biomass. This efficiency of C conversion of biomass to bio-char is highly dependent on the type of feedstock, but is not significantly affected by the pyrolysis temperature (within 350–500 ^∘C common for pyrolysis). Existing slash-and-burn systems cause significant degradation of soil and release of greenhouse gases and opportunies may exist to enhance this system by conversion to slash-and-char systems. Our global analysis revealed that up to 12% of the total anthropogenic C emissions by land use change (0.21 Pg C) can be off-set annually in soil, if slash-and-burn is replaced by slash-and-char. Agricultural and forestry wastes such as forest residues, mill residues, field crop residues, or urban wastes add a conservatively estimated 0.16 Pg C yr⁻¹. Biofuel production using modern biomass can produce a bio-char by-product through pyrolysis which results in 30.6 kg C sequestration for each GJ of energy produced. Using published projections of the use of renewable fuels in the year 2100, bio-char sequestration could amount to 5.5–9.5 Pg C yr⁻¹ if this demand for energy was met through pyrolysis, which would exceed current emissions from fossil fuels (5.4 Pg C yr⁻¹). Bio-char soil management systems can deliver tradable C emissions reduction, and C sequestered is easily accountable, and verifiable.     

土壤、农业与全球气候变化

本文讨论土壤、农业与全球气候变化的相互关系及相互影响,包括土壤圈、农业生产活动对全球气候变化的影响,以及全球气候变化对农业产生的直接和间接影响.并对引起CO2浓度上升、气温增高和水文条件改变等对世界农业和中国农业的正、负面效应进行预测、评估.     

A Quantitative Analysis of Energy Dissipation among Three Typical Air Entrainment Phenomena

This study investigates energy dissipation due to air bubble entrainment for three typical phenomena; a hydraulic jump, a 2-D vertical plunging jet and a vertical circular plunging jet into water. A simple model is presented here which enables to estimate the energy transformation and dissipation achieved by air bubbles quantitatively for three above phenomena. The average rate of energy dissipation by air bubbles obtained from the experimental data are 25%, 1.4%, and 2.15% with respect to total energy loss for the hydraulic jump, 2-D vertical plunging jet and vertical circular plunging jet, respectively.     

Weapon size versus body size as a predictor of winning in fights between shore crabs, Carcinus maenas (L.)

Relative body size (carapace width) and weapon size (chela length) were used as indicators of resource holding potential (RHP) in the agonistic behaviour of male shore crabs, Carcinus maenas (L.). Weapon size was found to be a more reliable predictor of the outcome of pairwise fights than body size. Crabs with longer chelae than their opponents were more likely to win fights than crabs with relatively larger bodies. Body size had less influence on the outcome of fights. Relative body and weapon size did not influence initiation of contests but did affect the likelihood of winning; however, this was significant only for weapon size. Winning crabs had heavier claws with greater surface area than losing crabs. There was no relationship between relative size and fight duration. The frequency of cheliped display increased with chela length and win- ners performed significantly more displays than losers. Received: 5 February 1997 / Accepted after revision: 20 May 1997     

基于Meta分析的安全氛围与安全绩效的关系研究*

为更系统地归纳安全氛围与安全绩效的关系,探究安全氛围、安全绩效及安全结果间的影响机制,采用Meta分析方法,通过2000—2020年54篇文献的55个独立研究样本进行定量综合分析,并进一步探讨安全氛围与安全绩效各维度间的关系,同时运用Meta二元回归探究潜在调节变量对2者间关系的调节作用。结果表明:安全氛围显著正向影响安全绩效,在高危行业中安全氛围对安全绩效影响更大;安全氛围与安全参与、安全遵守均显著正相关,且安全氛围对安全参与的影响强于对安全遵守的影响;安全氛围和安全绩效均与安全结果显著负相关,且安全绩效对安全结果的影响强于安全氛围对安全结果的影响。     

尾矿库事故隐患及风险表征与防控方法*

为解决尾矿库安全隐患及风险,应用基于证据(Evidence-based)方法和事故树分析模型,辨识并表征尾矿库事故影响因素、隐患及耦合状态,根据事件发生可能性、潜在后果严重性和受体暴露程度相关独立参数,给出尾矿库事故风险表征方法,建立尾矿库事故多情景、多阶段（3段）、多层次和多等级（4级）风险防控框架。结果表明:对尾矿库5类事故（溃坝、漫顶、渗流、输送冒漏、库区扬尘）进行分析,得出基本事件或蛰伏隐患对尾矿库事故结构重要度或影响程度,给出尾矿库事故风险3维表征方法,并结合巴西布鲁马迪尼奥尾矿库进行实例应用,确定尾矿库风险等级（最高级4级）,验证方法可行性与有效性。研究结果可为尾矿库减灾防灾提供理论支撑与实践指导。     

The future of global warming: will it be emissions control or environmental damages?

This paper explores the role of risk perceptions in influencing public policy related to global warming. It solves for the optimal paths for emissions, abatement and investment in pollution-eliminating research by incorporating perceived risks into public decision making. It also compares the impact of differential risk perceptions on international collaboration on carbon abatement. Key findings are that the perception of risks related to environmental damages and technological breakthroughs plays an important role in determining the level of mitigation efforts. A high level of perceived risk of environmental damages discourages investment in pollution-eliminating research as there are few benefits from eliminating pollution after damages are realized. Other options that allow for sequestering carbon from the atmosphere may still remain viable. Another key finding is that when it comes to effort sharing between nations, differential mitigation efforts are primarily caused due to the differences in abatement technology, benefits from emissions and research capabilities. However, such differences could be accentuated or mitigated depending upon the differences in risk perception of developed and developing countries.     

全球气候变暖成因分析

论述了太阳辐射、大气环流和地表状况是形成气候的3个基本因素.此外,还有人类活动、太阳活动、火山活动等影响气候变化的第4类因子.影响全球气候变暖的因素既有自然因素,也有人为因素.但导致近百年全球气候持续变暖的主要因素是人为因素(人类活动),即自19世纪末工业革命后,世界各国工业化、城市化快速发展,使大气中CO2等“温室效应“气体持续增加,而森林植被遭到大量砍伐和破坏,全球森林植被覆盖率持续下降,平衡大气中CO2与O2的生态功能不断下降,结果导致全球“温室效应“持续增强,使近百年来全球气候持续变暖.自然因素太阳活动对全球气候变暖的影响是周期性而不是持续性的.太阳活动增强期(高峰期)有增温作用,减弱期(低谷期)有降温作用,对全球气候变暖有影响,但比起人类活动造成的CO2等气体“温室效应“持续增强对气候持续变暖的影响相对较小.     

基于微震活动性参数的矿山灾害风险性评价

微震灾害分级是判别及处理高风险采场的关键。为了预测并防治采空区失稳导致的灾害,结合用沙坝矿引进的IMS微震监测系统,首先统计矿山尺度的微震活动性特征,将主要采场进行分区。然后分析各分区的最大潜在震级及其重现时间、微震扩散率、微震劲度比、能量频次等特征。最后结合采场微震灾害风险性分级标准对各分区风险性进行分级。结果表明,综合考虑微震事件的能量分布特征、空间分布特征、时间分布特征进行灾害风险性分级的结果更为合理。