低压下近熄灭极限区域纸火蔓延实验研究

对低压下的近熄灭极限区域水平纸火蔓延进行了实验研究。通过降低环境压力和氧气浓度,确定了水平纸火蔓延的着火极限,并得出了在极限氧气浓度条件下的火蔓延速度变化规律。在相同氧气浓度下(43%)进行了不同压力的水平纸火蔓延实验。结果表明,火蔓延速度在近熄灭极限区域内非线性增加,通过比较分析前人火蔓延速度实验结果,确定了火蔓延近熄灭极限区域和线性增长区域的分界压力值。此外,得出了压力分界处的火焰变化特征,并根据火焰图像与理论分析,得出了不同区域内的火蔓延传热机制。     

中国华南地区持续干期日数时空变化特征

利用华南地区46个地面气象站1960-2012年逐日降水数据,分析该地区各季节持续干期日数的时空分布特征。结果表明：1）近53年来,华南地区春季和夏季的持续干期日数呈波动下降趋势,下降速率分别为0.042和0.108 d·（10 a）-1;秋季和冬季的持续干期日数呈波动上升趋势,上升速率分别为1.911和0.118 d·（10 a）-1。广东省春季和夏季持续干期日数呈下降趋势,下降速率分别为0.171和0.243 d·（10 a）-1;秋季和冬季持续干期日数呈增加趋势,增加速率分别为1.737和0.32 d·（10 a）-1。广西省春、夏和秋季持续干期日数呈增加趋势,增加速率分别为0.109、0.046和2.117 d·（10 a）-1;冬季为减小趋势,减少速率为0.106 d·（10 a）-1。2）华南地区持续干期日数在春季呈从北向南逐渐增多的趋势,夏季呈自西南向东北逐渐增加的趋势,秋季呈自西向东逐渐增加的趋势,冬季呈从北向南逐渐增多的趋势。冬季的持续干期日数是4个季节中最长的,大致在20~44 d。3）华南地区春季持续干期日数变化倾向率在-1.20~1.00 d·（10 a）-1之间,增加趋势最明显的区域是广西省的南部地区,减少趋势最明显的区域是广东省的沿海地区;夏季在-1.00~0.60 d·（10 a）-1之间,呈增加趋势的区域主要位于广西省的中部和南部,呈减少趋势的区域位于广东省大部分地区和广西省的东部;秋季在0~3.50 d·（10 a）-1之间,整体呈现增加趋势,变化倾向率较大的区域主要位于广西省的中部和广东省的东北部沿海地区;冬季在-1.50~2.00 d·（10 a）-1之间,呈增加趋势的区域主要集中在广东省的中南部和东部地区,以及广西的东部边缘,呈减少趋势的区域主要集中在广东省的北部以及广西的中部和西北部地区。持续干期日数增加趋势最明显的季节是秋季。4）持续干期日数与降水量表现出负相关性,与气温和无降水日数表现为正相关性。降水量和无降水日数的变化对持续干期日数的变化起着重要的作用,而温度对持续干期日数的影响比较小。     

Uncertainties in a risk management context in early phases of offshore petroleum field development

The current risk management approach for the Norwegian offshore petroleum industry came into effect in 2001 and has been stable with minor changes for 15 years. Relatively few new installations were slated for development until quite recently, and several new projects have been started in the last few years. The paper considers the risk management approach in the pre-FEED phase and builds on two case studies selected from the most recent cases. These case studies have been evaluated with respect to how uncertainties are considered in the early phase, based on the submission of the Plan for Development and Operation, their evaluations by authorities and the supporting documents. Both case studies involve new concepts for which there is no experience from similar environments and/or water depths. In spite of what could have been expected, the case studies conclude that uncertainties have not been in focus at all during concept development. This appears to be definitely the case for the licensees, but also to be the case for the authorities. Some suggestions are presented for what could have been considered by the licensees and authorities.     

浅析低碳技术的评价方法

低碳技术可分为3类:减碳技术、无碳技术、去碳技术,选择最优低碳技术是一个项目能否成功的关键。低碳技术评价的内容通常从能源使用率、经济效益、生命周期方面进行评价,对技术的综合性评价的基本方法大致有层次分析法、综合评分法、德尔菲法、熵值法、模糊综合评判法等,这些方法渗透于指标权重分析、模型建立评价当中。通过研究对这些技术的评价方法,确定最优的技术项目,以促进循环经济及可持续发展战略的实施和进行。     

Verification of the geographical origin of modeled air-mass trajectories by means of the isotope composition of rainwater during the SALLJEX experiment

The SALLJEX experiment was held during the summer 2002–2003. It consisted of three-dimensional observation of the atmosphere to study the structure of the low level jet along the eastern slopes of the Andes. Daily precipitation water samples were collected at two stations (Resistencia and Salta) in northern Argentina and isotope content was analyzed. The isotope data were used in conjunction with air parcel trajectories obtained from a 3-D kinematic model (3D-MTC) developed by the University of Sao Paulo, Brazil. Values of deuterium excess were related with air masses of continental origin, whilst low values were associated with air masses with longer oceanic trajectories. Furthermore, although data are scarce, results show that oxygen-18 and deuterium excess in rainwater are related with the occurrence of the low level jet.     

氯氟烃化合物对臭氧层的影响---浅谈制冷剂R22替代R502的价值与技术

从保护臭氧层,保护环境的角度出发,介绍了氯氟烃化合物对环境的影响。阐述了用制冷剂R22代替R502在低蒸发温度应用时需要解决的问题和如何解决。     

连续流动分析法测定降水中铵盐的可行性研究

铵盐是降水监测的重要指标之一,它对降水中的酸性物质具有中和作用。将连续流动分析法应用于降水中铵盐的检测,并对该方法的检出限、精密度、加标回收率等一系列实验室质量要求进行了测定;在此基础上,用连续流动分析法和国家标准分析方法进行比对试验。对测试结果进行数理统计分析后证明,连续流动分析法与国标方法无显著性差异。     

低中放废物处置场核素经地下水迁移对环境影响预测

研究了我国某民用低中放固体废物处置场核素迁移的途径，对核素在地下水中的迁移进行了详细分析与计算，假定正常释放或一次降水量达到６００ｍｍ，处置场底浸泡一个月，存在６ｍ的包气带时，对该处置场处置的７种核素进行预测，结果表明，包气带是延迟核素迁移的主要屏障，在５００年内，可以使＾６０Ｃｏ＾１３７Ｃｓ＾９０Ｓｒ、＾６３Ｎｉ等核素延迟，其中＾２３９Ｐｕ降低６个月数量级，但不能延迟＾３Ｈ和＾１４Ｃ的迁移，穿过     

Effects of solution conditions on the precipitation of phosphate for recovery. A thermodynamic evaluation

To understand the effects of solution conditions on the precipitation of calcium phosphates from wastewater for recovery, a computer programme PHREEQC was employed to calculate the speciation and saturation-index (SI) with respect to hydroxyapatite of a chemically defined precipitation system, which contains phosphate of 1–200 mg P/l, with Ca/P molar ratios of one to 10 times of the stoichiometric calcium to phosphorus molar ratio of hydroxyapatite, at a pH range of 7.0–11.0. The results show that the SI is respectively the logarithmic function of the phosphate concentration and the calcium concentration, increasing with the increase of either of them; the SI is a polynomial function of the solution pH value and increases with its increase, and the effect of solution pH value is due to its influence on base uptake of the precipitation reaction and the speciation of phosphate and calcium ions; the SI is also a logarithmic function of the solution ionic strength but decreases with its increase; at the temperature range of 5–30 °C the SI increases linearly with solution temperature and the effect of temperature is also due to its influence on the speciation of phosphate and calcium ions.     

论北京降水的酸性

1994～1995年在北京市区安慧里进行了降水观测,分析了降水离子浓度,对夏季典型气象条件下的降水事件进行了后推气流轨迹分析?结果表明,北京市区年降水pH均值为5左右,夏季pH值最低,平均为4.88,说明北京出现了酸雨?气流轨迹分析显示,S-E扇形方向来流的降水酸度高;N-W扇形方面来流的降水酸度低?