Effect of acidic deposition on productivity of forest ecosystem and estimation of its economic losses in southern suburbs of Chongqing

In accordance with principle sand methods of ecology,this paper studied the effects of acidic deposition on productivity and volume increment of masson pine and Cinnamomum campora forest which are widely distributed in southern suburbs of Chongqing. Based on the field data and measurements, a multivariable stepwise regression model was established to analyze the effects of multiple environmental factors on the productivity of the forest ecosystems. This model was used to assess the volume and economic losses of these two forest ecosystems caused by acidic deposition. The results showed that, among the environmental factors, pH value of precipitation, soil depth, soil organic contents and slope are the dominant ones influencing the growth of masson pine forest. It is also shown that the acidic deposition has no clear relation to the growth of C.Campora forest, so development of such broad-leaved forest is suitable in the area.     

辽东湾近岸冰区营养要素的含量及其分布特征初探

本文根据１９９６年１月下旬在辽东湾近岸具有代表性的冰区所采集的水样和冰样中营养要素的实测结果，对海水和海冰中的ＮＯ－３－Ｎ、ＮＯ－２－Ｎ、ＮＨ＋４－Ｎ、ＰＯ３－４－Ｐ、ＳｉＯ２－３－Ｓｉ等营养要素的含量及其分布特征进行了初步的探讨。结果表明，辽东湾近岸冰区营养盐含量较为丰富，而且营养盐的含量基本呈现出海水中的含量高于海冰中含量的分布状态。     

酸沉降对重庆南岸马尾松针叶林年生物生产量的影响及其经济损失的估算

利用生态学方法研究了酸沉降对重庆南岸马尾松针叶林和樟树阔叶林年生物生产量及年材积生长量的影响．在野外调查观测的基础上，用多元逐步回归法分析了诸多环境因子对两种森林生态系统年生物生产量的影响，并估算了酸沉降引起的重庆南岸（酸雨严重危害地区）马尾松针叶林的年材积损失量和生态经济损失值．结果表明，在诸多环境因子中，土壤有机质含量、降水ｐＨ值、土层厚度及坡度是影响马尾松针叶林生长的主导因子，其与生物量的相关系数分别为０．９９４０、０．９７６２、０．９７３８、０．９４３６．由此引起的重庆南岸马尾松针叶林的直接经济损失达３０３．３２万元／ａ；酸沉降对樟树阔叶林无显著影响，建议在该地区发展樟树阔叶林．     

Loss of ozone on sulfate and sulfide doped-ice surfaces

ＩｎｔｒｏｄｕｃｔｉｏｎＯｚｏｎｅｐｌａｙｓａｃｒｉｔｉｃａｌｒｏｌｅｉｎｔｈｅｅａｒｔｈ’ｓｅｃｏｌｏｇｉｃａｌｂａｌａｎｃｅｏｗｉｎｇｔｏｉｔｓｓｔｒｏｎｇａｂｓｏｒｐｔｉｏｎｏｆｂｉｏｌｏｇｉｃａｌｌｙｄａｍａｇｉｎｇｉｎｃｏｍｉｎｇｕｌｔｒａ...     

现代环境事件的冰芯记录

1997年9月，在喜马拉雅山中段希夏邦马峰北坡达索普冰川海拔7000m冰雪平台钻取14m冰芯一支。1990年以来冰芯中主要离子浓度的变化表明，现代环境事件在达索普冰川雪冰中有一定的记录。已有的证据表明1991年达索普冰芯中SO^2-4浓度的最高值最大可能是由海湾战争引发的1991年春季科威特油井燃烧污染物所致。冰芯中陆源离子（如Ca^2 和SO^2-4等）记录与我国西北地区春季沙尘暴具有某些相关性，其逐年变化趋势与新疆13个城市的降尘变化有一定的共性。     

渤海湾南部沿岸海区1992—1995年结冰特征与分析

本文对渤海湾南部沿岸海区１９９２－１９９５年冬季现场海冰的实测资料进行了分析总结，探讨研究了该海区海冰的外貌特征，冰情特性及生消变化情况，并对影响该海区冰情的最重要因素－气温与海冰的关系进行了分析。     

Low intensity ultrasound stimulates biological activity of aerobic activated sludge

This work aims to explore a procedure to improve biological wastewater treatment efficiency using low intensity ultrasound. The aerobic activated sludge from a municipal wastewater treatment plant was used as the experimental material. Oxygen uptake rate (OUR) of the activated sludge (AS) was determined to indicate the changes of AS activity stimulated by ultrasound at 35 kHz for 0–40 min with ultrasonic intensities of 0–1.2 W/cm². The highest OUR was observed at the ultrasonic intensity of 0.3 W/cm² and an irradiation period of 10 min; more than 15% increase was achieved immediately after sonication. More significantly, the AS activity stimulated by ultrasound could last 24 h after sonication, and the AS activity achieved its peak value within 8 h after sonication, or nearly 100% higher than the initial level after sonication. Therefore, to improve the wastewater treatment efficiency of bioreactors, ultrasound with an intensity of 0.3 W/cm² could be employed to irradiate a part of the AS in the bioreactor for 10 min every 8 h. Translated from Environmental Science, 2005, 26(4): 124–128 [译自: 环境科学]     

Prediction of aqueous solubility of PCBs based on molecular structure

The thermodynamic relationships among aqueous solubility and molar volume (MV) , total molecular surface area (TSA) and molecular connectivity index (MCI) for highly hydrophobic chemicals. PCBs are established and discussed, respectively. Good linear relationships exist among In Cs and MV, TSA or MCI.     

客舱玻璃抗螺旋桨甩冰冲击分析

目的 研究涡桨飞机客舱玻璃抗螺旋桨甩冰分析方法。方法 根据某型涡桨飞机螺旋桨结冰特性计算分析得到的冰块质量以及冰块轨迹,筛选出严重载荷工况。建立客舱玻璃有限元模型,采用有限元软件PAM-CRASH进行数值计算,获得结构破坏形态和动态响应。开展客舱玻璃甩冰冲击研发试验,将试验后结构损伤与数值分析结果进行对比分析。结果 两种确定冰块质量和冰块速度方法,可适用于结构防甩冰设计的不同阶段;根据结冰特性计算分析得到的冰块质量10.27 g、垂向速度141.1 m/s更为准确合理。不同冰型撞击各个结构部位,会对结构造成不同程度的损伤。同一长方体冰型下,入射截面积越小,玻璃损伤越严重;撞击玻璃不同部位时,角部比中心点更为严重。结论 试验结果与仿真结果基本一致,可以验证所给出的客舱玻璃分析模型及分析方法的准确性,可供螺旋桨甩冰区域的客舱玻璃设计参考。     

藻华高风险期微囊藻在洱海中的垂直分布特征及其影响因素

大量微囊藻浮力调节及其垂向迁移是形成蓝藻水华的重要机制之一.为研究微囊藻的垂直分布特征及影响因素,以洱海北部湖心为监测点位,采用野外采样室内分析的方法,于2016年9—12月对微囊藻生物量、伪空胞体积、粒径等指标进行了测定.结果表明:9—11月微囊藻生物量逐月增长并于11月达到峰值（1.77 mg/L）,在12月出现下降（月均值为0.34 mg/L）;9月、11月微囊藻伪空胞体积（18.0~22.6 μm3/cell）较高,10月、12月较低（10.2~17.3 μm3/cell）;9—11月微囊藻的垂向迁移速率（5.4~14.5 m/d）、漂浮百分率（57%~96%）及群体粒径（91~305 μm）逐渐增大,12月明显减小.微囊藻生物量、伪空胞体积及群体粒径的垂直分布规律均表现为表层最高,中层次之,底层最低.9—11月,微囊藻在洱海中出现垂直分层现象,伪空胞提供的浮力作用和藻群体粒径作用大于风力扰动作用,促使微囊藻在水柱中主动迁移并聚集在水面;而在12月,风力扰动对微囊藻垂直分布的影响远超过浮力及粒径的作用,微囊藻在水柱中趋于均匀分布.研究显示,藻华高风险期微囊藻在洱海呈弱分层分布,且浮力及群体粒径是影响其垂直分布的主要因子.