长江流域点源氮磷营养盐的排放、模型及预测

通过分析1985～2003年长江流域向河口/东海排放的点源营养盐的时空变化规律,建立长江点源营养盐排放模型,并预测2020年长江流域点源氮磷排放情况.模型基于人口密度、国内生产总值、人均氮磷排放量、以及污水处理率等因子,在99%的置信度上,氮磷模型的方差解释量分别达到92.3%及93.2%.基于此模型预测2020年长江流域点源氮排放量将达到(95 9±6 6)×104t,点源磷排放量达到(12.3±0.6)×104t.此外,研究结果进一步表明,点源营养盐通量仍然是长江输送营养盐总量的主要部分,是影响河口/近海水质的主要因素.     

居住区地下车库噪声在建筑群间的传播和影响模拟计算

针对城市居住区2种典型的建筑布局,结合随机点声源模型,对居住区内地下车库噪声影响进行了分析计算.通过实测值和预测值的比较,该预测模型精度较好.运用该模型预测规划与新建的居住区地下车库的噪声的影响,可为城市小区建设规划中有效控制噪声污染提供科学依据.     

美国AERMOD模型与中国大气导则推荐模型点源比较

介绍了美国AERMOD模型和中国大气导则推荐模型一般浓度公式,通过大气稳定度和扩散参数的确定、复杂地形处理和对流条件下污染物扩散等原理方面的比较认为,AERMOD模型优于大气导则推荐模型.以美国环境保护局(USEPA)2个试验场Clifty Creek(平坦地形)和Lovett(复杂地形)的数据资料为比较数据,分别用AERMOD模型和大气导则推荐模型计算SO₂小时质量浓度,在Pasquill 6类稳定度下用相对偏差(FB)、预测值与观测值的比率(RHC_R)及图形法(Q-Q图)等进行模型比较,结果表明:在RHC_R和FB中,AERMOD模型除个别值外,其他均好于大气导则推荐模型;而大气导则推荐模型存在接近或大于模型可靠性界限0.67(0.66和0.74),说明其可靠性比AERMOD模型差;图形法比较中,强不稳定和不稳定下AERMOD模型明显好于大气导则推荐模型,而大气导则推荐模型预测值明显偏低,其他稳定度下结果相差不大.研究认为:在平坦地形和复杂地形条件下,AERMOD模型点源预测值均优于大气导则推荐模型,并从原理上进行了解释.      

中国安全生产大趋势已进入拐点——生产安全事故宏观预警与发展态势分析

为认清我国安全生产形势现状与发展趋势,作者应用比较研究和预测分析方法,回顾总结了我国生产安全事故历史演变特点,对事故死亡人数、十万死亡率和重大事故发生频率等安全生产指标作了近中期预测模拟分析;结合我国经济社会发展现状,提出了中国安全生产大趋势已进入拐点的判断,并建议在新的历史机遇面前,对安全生产监管模式做重大调整,推进安全生产形势根本性好转,实现安全发展。     

聚氨酯泡沫材料阴燃发展过程的特性分析

分析对比了相同加热条件下的聚氨酯泡沫材料在有氧和无氧气氛下的升温过程,并对不同加热条件下的聚氨酯泡沫材料的阴燃传播速度进行研究.结果表明:沿着反应进行的方向,分离点的温度越来越低,不同热流条件下的温度分离曲线斜率在实验稳定发展段的变化规律表现得很相似,并在分离点出现后,有氧气氛中的该位置温度在短时间内急剧上升;在阴燃不稳定传播阶段时,热解前锋的速度小于氧化前锋的速度,在稳定传播阶段时,热解前锋速度与氧化前锋速度近乎相等.     

The determination and matching analysis of pinch point temperature difference in evaporator and condenser of organic rankine cycle for mixed working fluid

Exergo-economic analysis of the pinch point temperature difference (PPTD) in both evaporator and condenser of sub-critical organic Rankine cycle system (ORCs) are performed based on the first and second laws of thermodynamics. Taking mixture R13I1/R601a as a working fluid and the annual total cost per net output power Z as exergo-economic performance evaluation criterion, the effects of PPTD in evaporator ΔT_e, and the PPTD ratio of condenser to evaporator y, on the exergo-economic performance of ORCs are analyzed. Moreover, how some other parameters influence the optimal PPTD in evaporator ΔT_e,opt and the optimal PPTD ratio of condenser to evaporator y_opt are also discussed. It has been found that the exergo-economic performance of ORCs is remarkably influenced by ΔT_e and y, and there exists ΔT_e,opt and y_opt. In addition, ΔT_e,opt and y_opt are affected by heat transfer coefficient ratio of condenser to evaporator ß, the temperature of working fluid at dew point in condenser T_1a, and composition of R13I1/R601a: larger ß and T_1a lead to lower ΔT_e,opt and y_opt; by contraries, larger mass fraction of R13I1 makes ΔT_e,opt and y_opt increase, and y_opt increases linearly. The effects of the temperature of working fluid at bubble point in evaporator T_3a, mass flow rate of exhaust flue gas m_g, and inlet temperature of exhaust flue gas T_gi on ΔT_e,opt and y_opt are very slight. For comparison, three additional working fluids, namely R601a, R245fa, and 0.32R245fa/0.68R601a, are also taken into account.     

Regime shifts and resilience in China’s coastal ecosystems

Regime shift often results in large, abrupt, and persistent changes in the provision of ecosystem services and can therefore have significant impacts on human wellbeing. Understanding regime shifts has profound implications for ecosystem recovery and management. China’s coastal ecosystems have experienced substantial deterioration within the past decades, at a scale and speed the world has never seen before. Yet, information about this coastal ecosystem change from a dynamics perspective is quite limited. In this review, I synthesize existing information on coastal ecosystem regime shifts in China and discuss their interactions and cascading effects. The accumulation of regime shifts in China’s coastal ecosystems suggests that the desired system resilience has been profoundly eroded, increasing the potential of abrupt shifts to undesirable states at a larger scale, especially given multiple escalating pressures. Policy and management strategies need to incorporate resilience approaches in order to cope with future challenges and avoid major losses in China’s coastal ecosystem services.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0692-2) contains supplementary material, which is available to authorized users.     

浊点萃取分离富集荧光光度法测定水中α - 萘酚

基于非离子表面活性剂Triton X-114,采用浊点萃取分离富集荧光光度法测定水中α-萘酚,优化了影响浊点萃取的各种因素,包括样品酸度、表面活性剂体积分数、氢氧化钠溶液浓度、平衡温度和时间等,讨论了常见无机离子和可能共存的有机物的干扰。方法在0.010 mg/L～0.400 mg/L范围内线性良好,检出限为3.0μg/L,标准溶液测定的RSD为4.8%,水样加标回收率为94.3%～103%。     

Spectral tests of randomness for spatial point patterns

We develop a spectral framework for testing the hypothesis of complete spatial randomness (CSR) for a spatial point pattern. Five formal tests based on the periodogram (sample spectrum) proposed in Mugglestone (1990) are considered. A simulation study is used to evaluate and compare the power of the tests against clustered, regular and inhomogeneous alternatives to CSR. A subset of the tests is shown to be uniformly more powerful than the others against the alternatives considered. The spectral tests are also compared with three widely used space-domain tests that are based on the mean nearest-neighbor distance, the reduced second-order moment function (K-function), and a bivariate Cramér-von Mises statistic. The test based on the scaled cumulative R-spectrum is more powerful than the space-domain tests for detecting clustered alternatives to CSR, especially when the number of events is small.     

青岛市主干道沿线高层建筑的交通噪声研究

采用A计权网络对青岛市东西快速路沿线高层建筑进行监测。利用Grapher软件,以Leq为监测值的基准值绘制连续线状图,分析城市主干道周边高层建筑上交通噪声的峰值点。根据道路中心线到高层建筑的距离信息,得出高层建筑交通噪声峰值点与道路中心线的连线与水平地面间的角度约为30°。