The influence of season and leaf age on concentrations of radiocaesium (137Cs), stable caesium (133Cs) and potassium in Agrostis capillaris

The transfer of radioactive caesium from soils to plants has been well researched. In contrast there is limited knowledge on natural stable 133Cs and its potential role as a predictor for radiocaesium behaviour. In a pot experiment with Agrostis capillaris close correlations were found between plant 137Cs and plant 133Cs concentrations (R2 90-96%). Season and leaf age had significant effects with concentrations increasing 10-30-fold between June and December. Simultaneously the plant concentrations of K, the nutrient analogue of Cs, decreased to around one third. In the soil the exchangeable fractions of K and 137Cs declined. No clear relationships were found between 137+133Cs in the plant and exchangeable K in the soil. However, at the end of the experiment the K content of the above-ground biomass was higher than the exchangeable pool in the soil, suggesting that depletion of soil K could be a key factor in the observed increase of plant 137+133Cs over time.     

Mercury in some chemical fertilizers and the effect of calcium superphosphate on mercury uptake by corn seedlings(Zea mays L.)

Mercury (Hg) contents in ten chemical fertilizers were determined, and the effect of calcium superphosphate (CSP) on the uptake and translocation of Hg in corn seedlings was investigated by pot experiments. CSP was applied at the levels of 0, 66.7, and 133.4 mg P2O5/kg to Hg-treated (2 mg/kg) and untreated soils. CSP had the highest Hg content (5.1 mg/kg), followed by the NPK compound fertilizer 15-5-5 (15% N, 5% P2O5, 5% K2O) (1.2 mg/kg), then by nitrogen fertilizers (except for ammonia sulfate) and potassium fertilizers. Application of CSP did not obviously iuence the biomass of corn roots, but it significantly increased the biomass of corn shoots in Hg-treated soil. Application of CSP at the levels of 66.7 and 133.4 mg P2O5/kg did not obviously iuence the uptake of Hg by corn seedlings on soils without Hg treatment, but it decreased the Hg uptake of corn seedlings significantly on Hg-treated soils. The transfer coefficient of Hg in corn seedlings improved slightly on soils without Hg treatment, but decreased slightly on Hg-treated soils with the application of CSP. These results implied that CSP could ameliorate Hg toxicity to corn seedlings by inhibiting the uptake and the translocation of Hg in plants on Hg-polluted soils.     

Impacts of environmental factors on urban heating

This study investigated the impact of important environmental variables (i.e.,wind speed,solar radiation and cloud cover) on urban heating.Meteorological parameters for fifteen years (from 1990 to 2005),collected at a well developed and densely populated commercial area (Tsim Sha Tsui,Hong Kong),were analyzed in details.Urban heat island intensity (UHII),a well known indicator of urban heating,has been determined as the spatially averaged air-temperature difference between Tsim Sha Tsui and Ta Kwu Ling (a thinly populated rural area with lush vegetation).Results showed that the UHII and cloud cover have increased by around 9.3% and 4%,respectively,whereas the wind speed and solar radiation have decreased by around 24% and 8.5%,respectively.The month of December experienced the highest UHII (10.2°C) but the lowest wind speed (2.6 m/sec) and cloud cover (3.8 oktas).Conversely,the month of April observed the highest increases in the UHII (over 100%) and the highest decreases in wind speed (over 40 %) over fifteen years.Notably,the increases in the UHII and reductions in the wind speed were the highest during the night-time and early morning.Conversely,the intensity of solar radiation reduced while the intensity of urban cool island (UCII) increased during solar noon-time.Results demonstrated strong negative correlation between the UHII and wind speed (coefficient of determination,R2=0.8) but no negative correlation between UCII and solar radiation attenuation.A possible negative correlation between UHII and cloud cover was investigated but could not be substantiated.     

化工企业突发事件信息传递效能模糊综合评价

在分析化工企业突发事件信息传递影响因素的基础上,初步建立了信息传递效能评价指标体系,并运用模糊综合评价方法通过实例进行计算和分析,结果表明该指标体系及评价方法适用于化工企业突发事件信息传递效能的评价。     

塑胶运动场有机污染与热污染分析

本研究选择了合肥市有代表性的塑胶跑道和运动场,用GC-MS监测分析了塑胶跑道周围空气中刺激性气体的主要污染物成分;在不同天气条件下,对不同类型运动场地的热污染进行了对比测量分析;最后在上述研究分析的基础上对塑胶运动场的建设、使用提出了对策和建议。     

地源热泵对武汉节能减排的影响分析

地源热泵是利用浅表地热能实现空气温度调节的新技术,具有节能、环保的明显效应。武汉独特的地理气候条件和丰富的地下水资源使得地源热泵系统具有广阔的发展空间,示范工程的成功运行为大规模推广地源热泵技术提供了可靠依据。在武汉建设"两型社会"进程中,应采取总体规划、集中管理、专项扶持和鼓励创新等措施,以充分发挥地源热泵技术对武汉"节能减排"的重要作用。     

微曝气垂直流湿地中4种基质的充氧性能研究

通过模型曝气实验研究了公分石、火山石、500级陶粒、高强级陶粒4种基质和空白水柱分别在0.19、 0.38、 0.76 m³·(m²·h)^-1 3种曝气强度下的充氧性能.结果表明,在相同条件下,曝气强度越大,氧转移速率常数K_La越大,填充了基质的模型的氧转移速率常数比空白提高了5～7.8倍;在0.19 m³·(m²·h)^-1曝气强度下,500级陶粒和高强级陶粒的氧利用率最高,分别为14.39%和14.21%,火山石和公分石的氧利用率分别为13.11%和11.68%;随着曝气强度的提高,公分石的氧利用率明显高于其它基质,在0.38 m³·(m²·h)^-1曝气强度下达到最大值14.04％,比该状况下空白模型的氧利用率高出3倍,火山石的氧利用率持续下降,在0.76 m³·(m²·h)^-1曝气强度下,氧利用率为7.67%,500级陶粒和高强级陶粒的氧利用率较为稳定,维持在10%左右.     

减压转油线局部更换应注意的重要环节——冷紧

分析了蒸馏装置减压塔进料接管角焊缝开裂、泄漏原因,阐述了减压转油线冷紧的重要性及检修中应注意的问题。     

新建装置伴热管线设计问题分析及整改措施

就某公司新建的制加氢联合装置伴热管线设计不能满足开工和伴热需求问题进行了分析,针对伴热管线设计中存在问题,提出整改措施,并且加以实施,最终保证了新建装置在-40℃的冬季顺利开工。     

基于Landsat TM/ETM+的天津城区及滨海新区热岛效应时空变化研究

利用1987年、1998年、2004年和2008年4景Landsat TM/ETM+数据的热红外波段数据反演天津市地表亮温,并对绝对亮温值进行归一化处理得到相对亮温。通过对相对亮温分布图进行时空分析可知,自1987年到2008年,天津市热岛效应主要发生在中心城区、滨海新区以及道路沿线等区域。热岛范围在加大,强度也在增加。中心城区热岛效应不断加剧,滨海新区的热岛效应则从无到有,从弱到强,变化十分明显。并分析了热岛现象产生和异常的原因,有降水变化、农作物收割、公路建设和建成区增加。