黔中黄壤坡耕地区域降水及其氮磷输入特征

黄壤坡耕地不仅具有“黏、酸、瘦”的特点,而且水土、养分流失普遍严重,引起一系列农业面源污染环境问题。以黔中黄壤坡耕地氮磷流失长期定位监测基地为平台,于2008─2012年连续5年进行观测,研究了降水及氮磷湿沉降浓度、总量及季节性变化等特征,探明了降雨带入的氮磷养分对黄壤坡耕地养分流失的贡献,为农业生产、农业面源污染防治对策提供科学依据。结果表明：2008─2012年间,年降雨次数变幅为46~109次,年均64次;年降雨量变幅为558.4~901.5 mm,年均695.7 mm;频次降雨量变幅为6.5~15.5 mm,平均10.9 mm。5年湿沉降TN、NO3--N、NH4+-N、TP浓度变幅,分别为1.57~3.31、0.17~0.79、0.10~0.94和0.06~0.48 mol·L-1,平均值分别为1.91、0.42、0.28、0.14 mol·L-1,均与降水量呈负相关,但未达到显著水平;5年湿沉降TN、NO3--N、NH4+-N、TP输入量变幅,分别为11.19~18.47、0.96~5.47、1.22~6.65和0.42~1.34 kg·hm-2·a-1,平均值分别为14.32、3.37、2.77、1.09 kg·hm-2·a-1,TN、TP输入量与降雨量呈正相关(相关系数分别为0.774、0.707,P值分别为0.0003、0.0015)。输入量季节性变化5─8月最为集中,5─7月TN输入量为6.95 kg·hm-2,占全年TN输入量的比例高达51.1%;6─8月TP输入量为0.49 kg·hm-2,占全年TP输入量的比例高达47.4%,即冬、春季较低,夏、秋季较高。湿沉降TN、TP输入量相当于当地施肥投入的氮、磷素总量的7.54%、1.14%,因此在农业生产中制定施肥方案时,可考虑坡耕地湿沉降养分的输入,尤其是氮养分的输入。     

“两带”渗透率分布模型应用及渗透率规律研究*

为了研究覆岩破坏后形成“两带”的渗透率分布规律,根据理论推导应力-应变曲线以及采空区材料力学参数公式,建立“两带”渗透率分布模型,采用COMSOL软件分别对垮落带的渗透率分布和断裂带渗透率分布进行数值模拟。研究结果表明:垮落带渗透率呈“椭圆”分布,渗透率最大可达到1.07×10-6 m2,最小可达到1.5×10-8 m2;随着高度的增加,采空区两侧的渗透率变化幅度增加,中部的渗透率变化值较小。断裂带渗透率呈“铲状”分布,靠近工作面区域渗透率最大,断裂带的渗透率在上下隅角处最大可达到1.8×10-10 m2,垂直方向上随着高度的增加渗透率减小。研究结果可为西部典型浅埋煤层安全高效开采提供现场指导作用。     

压缩空气泡沫在长距离管路输送中压降的数值模拟

基于Fluent对压缩空气泡沫在长距离管道中的流动特性进行了数值模拟研究,将压缩空气泡沫近似为弥散流,采用Saplart-Allmaras模型模拟了不同管径下压缩空气泡沫以及不同泡沫原液浓度的AFFF泡沫在长距离管道内的流动及压降变化。模拟结果表明,随着距离变化,各管径管道内压降均呈现线性变化,且随着压缩空气泡沫的流动,压降线性增大。管道管径对管内压降变化具有显著影响,管道直径越小,管道内压降越大;泡沫原液浓度对压降的影响较小,且压缩空气泡沫在长距离输送中的压力随距离线性衰减。将模拟结果与长距离输送的试验结果进行了对比,误差在10%以内。     

基于BERT-BILSTM-CRF模型的电力行业事故文本智能分析*

为解决电力行业事故报告文本较长、语义复杂,难以进行有效文本识别问题,提出1种以BERT作为底层的预训练模型,并设计1种双重注意力机制编码器,结合BILSTM-CRF深度挖掘事故文本语义特征,从而实现文本智能分析。首先构建电力词典,通过对BERT预训练,进行BIO标注,然后引入BILSTM-CRF模型实现对文本标签智能分类,最后将该模型与现行其他4种深度学习模型进行对比。研究结果表明:该模型智能识别精确率、召回率及F1值(查准率)均达到约97%,较其他4种模型中效果最好的模型分别提高0.02,0.03,0.02。研究结果可为电力行业事故报告文本分析提供1种新思路。     

Resident participation in post-Lushan earthquake housing reconstruction: a multi-stage field research method-based inquiry

In April 2013, a 7.0?Mw earthquake struck in Lushan County, Sichuan Province, China, causing serious housing damage. Housing reconstruction is a crucial part of disaster recovery, and resident participation has been recognized as a key part of reconstruction success. This paper examined housing reconstruction resident participation in the post-Lushan earthquake period as a multi-stage problem based on multi-stakeholder collaborative perspectives, which covered emergency shelter, temporary housing and permanent housing stages. Multi-stage field research was conducted in the affected areas, and the residents were found to be fully involved in the reconstruction with a ‘high – medium – high' distribution across the three stages. Resident participation experiences were summarized in terms of previous earthquake education, NGO participation and community-based organization functions, and the reasons discussed, such as civic awareness and civic rights. Problems regarding improper reconstruction and cultural conflicts were also examined and valuable suggestions given.     

Role of goethite dissolution in the oxidation of 2-chlorophenol with hydrogen peroxide.

It is well known that the dissolution of goethite plays an important role in catalyzing the oxidation of organic chemicals. Therefore, this study investigates how surface dissolution of goethite affects 2-chlorophenol oxidation in the goethite/H2O2 process. Experimental results indicate that ligand and reductant can enhance the dissolution rate of goethite, which is surface-controlled. Our results further indicate 2-chlorophenol degradation depends on goethite concentration. In addition, the oxidation rate of 2-CP is correlated with reductive dissolution rate at various dosages of goethite. Moreover, the oxidation mechanism of 2-CP is also a surface-controlled reaction. A mechanism proposed herein indicates that, in addition to the contaminant, its intermediate species affect the oxidation rate as well.     

Geostatistical analysis and risk assessment on soil total nitrogen and total soil phosphorus in the Dongting Lake plain area, China

Nonpoint-source pollution and water body eutrophication have become increasing concerns for scientists and policymakers. Nitrogen and phosphorus affect environmental pollution, especially lake eutrophication. To assess the environmental risk of soil total nitrogen (TN) and total phosphorus (TP) pollution, a typical ecological unit of Dongting Lake plain was selected as the experimental site. To verify the stationary of the data, a moving windows technique was adopted. Our results showed that Box-Cox transformation achieved normality in the data set and dampened the effect of outliers. The best theoretical model for semivariogram of TN and TP was a spherical model. The ordinary kriging estimates of TN and TP concentrations were mapped. The integrative comparisons of semivariogram parameters with different trends to the kriging prediction errors of TN and TP indicated that the two-order trend is preferable. Kriging SDs provided valuable information that will increase the accuracy of TN and TP mapping. The probability kriging method is useful to assess the risk of N and P pollution by providing the conditional probability of N and P concentrations exceeding the threshold concentrations of 3.2 and 1.05 g/kg, respectively. The probability distribution of TN and TP at different levels will be helpful to conduct risk assessment, optimize fertilization, and control the pollution of N and P.     

Vegetation and carbon sequestration and their relation to water resources in an inland river basin of Northwest China

In the Heihe River Basin in the arid inland area of northwest China, the distribution of water resources in vegetation landscape zones controls the ecosystems. The carbon sequestration capacity of vegetation is analyzed in relation to water resources and vegetation growing conditions. During the last 20 years, the vegetation ecosystems have degenerated in the Heihe River Basin. Simulation using the C-FIX model indicates that, at present, the total amount of NPP of vegetation accounts for about 18.16 TgC, and the average value is 106 gC/m(2)/yr over the whole basin. NPP has generally the highest value in the upperstream mountain area, middlestream artificial oases area, downstream river bank area, alluvial fan and the terminal lake depression where vegetation grows relatively well. The lowest value is found in the vast downstream desert and Gobi area. Protection of vegetation ecosystems and enhancement of carbon sequestration require such inland river basins as the Heihe River Basin to be brought under management in a comprehensive way, taking water as a key, to carry out a rational and efficient allocation and utilization of water resources.     

Water Hyacinth in China: A Sustainability Science-Based Management Framework

The invasion of water hyacinth (Eichhornia crassipes) has resulted in enormous ecological and economic consequences worldwide. Although the spread of this weed in Africa, Australia, and North America has been well documented, its invasion in China is yet to be fully documented. Here we report that since its introduction about seven decades ago, water hyacinth has infested many water bodies across almost half of China’s territory, causing a decline of native biodiversity, alteration of ecosystem services, deterioration of aquatic environments, and spread of diseases affecting human health. Water hyacinth infestations have also led to enormous economic losses in China by impeding water flows, paralyzing navigation, and damaging irrigation and hydroelectricity facilities. To effectively control the rampage of water hyacinth in China, we propose a sustainability science-based management framework that explicitly incorporates principles from landscape ecology and Integrated Pest Management. This framework emphasizes multiple-scale long-term monitoring and research, integration among different control techniques, combination of control with utilization, and landscape-level adaptive management. Sustainability science represents a new, transdisciplinary paradigm that integrates scientific research, technological innovation, and socioeconomic development of particular regions. Our proposed management framework is aimed to broaden the currently dominant biological control-centered view in China and to illustrate how sustainability science can be used to guide the research and management of water hyacinth.     

基于“人工智能”驱动的农村生活污水系统治理专栏序言

伴随流域水污染控制与治理工作的深入,农村分散生活污水治理逐渐成为制约流域水环境改善的关键.同时,农村生活污水治理是人居环境提升、美丽乡村建设以及乡村振兴战略实施的集中体现,事关广大农村居民的切身利益.本专栏是国家水专项“分散污水治理课题”团队近年来科研成果的总结,从污水治理的全生命周期角度出发,尝试通过人工智能赋能治理模式决策、“菜单式”工艺组合、设施运维与监管、长效管理等4个方面对研究和实践进行了梳理总结,构建基于人工智能驱动的农村生活污水治理决策支持系统,以期为北运河流域以及其他区域农村生活污水治理提供科技支撑.