Tracking nitrogen losses in a greenhouse crop rotation experiment in North China using the EU-Rotate_N simulation model

Vegetable production in China is associated with high inputs of nitrogen, posing a risk of losses to the environment. Organic matter mineralisation is a considerable source of nitrogen (N) which is hard to quantify. In a two-year greenhouse cucumber experiment with different N treatments in North China, non-observed pathways of the N cycle were estimated using the EU-Rotate_N simulation model. EU-Rotate_N was calibrated against crop dry matter and soil moisture data to predict crop N uptake, soil mineral N contents, N mineralisation and N loss. Crop N uptake (Modelling Efficiencies (ME) between 0.80 and 0.92) and soil mineral N contents in different soil layers (ME between 0.24 and 0.74) were satisfactorily simulated by the model for all N treatments except for the traditional N management. The model predicted high N mineralisation rates and N leaching losses, suggesting that previously published estimates of N leaching for these production systems strongly underestimated the mineralisation of N from organic matter.     

C/N比和曝气量影响MBR同步硝化反硝化的研究

通过连续运行MBR研究了C/N比和曝气量对同步硝化反硝化的影响，结果表明，在环境温度13～23℃，MLSS为6.0～6.8 g/L，进水NH⁺₄-N浓度50 mg/L，曝气量0.5 m³/h，HRT为6 h实验条件下，总氮去除率随着进水C/N比的增加而增加，在C/N比为6∶1～8∶1时，TN去除率达到79%～89%，低的C/N比抑制反硝化，过高的C/N比增加了碳源补加的成本。改变反应曝气量，当C/N比为6∶1，曝气量为0.4 m³/h时，TN的去除率达到了最大值85%。曝气量过高或过低，TN去除率均下降。并对在不同曝气量下MBR 内的DO 值分布进行了初步研究。     

A case study predicting environmental impacts of urban transport planning in China

Predicting environmental impacts is essential when performing an environmental assessment on urban transport planning. System dynamics (SD) is usually used to solve complex nonlinear problems. In this study, we utilized system dynamics (SD) to evaluate the environmental impacts associated with urban transport planning in Jilin City, China with respect to the local economy, society, transport, the environment and resources. To accomplish this, we generated simulation models comprising interrelated subsystems designed to utilize changes in the economy, society, road construction, changes in the number of vehicles, the capacity of the road network capacity, nitrogen oxides emission, traffic noise, land used for road construction and fuel consumption associated with traffic to estimate dynamic trends in the environmental impacts associated with Jilin's transport planning. Two simulation scenarios were then analyzed comparatively. The results of this study indicated that implementation of Jilin transport planning would improve the current urban traffic conditions and boost the local economy and development while benefiting the environment in Jilin City. In addition, comparative analysis of the two scenarios provided additional information that can be used to aid in scientific decision-making regarding which aspects of the transport planning to implement in Jilin City. This study demonstrates that our application of the SD method, which is referred to as the Strategic Environmental Assessment (SEA), is feasible for use in urban transport planning.     

加油站地下储油罐压力管理系统的相关研究

在当前普遍采用的加油站真空辅助式第二阶段油气回收系统中，为了避免回收到地下储油罐中的油气再次通过P/V阀排空，必须对其中气相空间的压力实施有效控制。从国外的发展情况来看，地下储油罐的压力管理系统主要分为基于膜分离技术、基于弹性气囊和基于活性炭吸附三大类，其中膜法油气回收装置在国内已经得到了较多关注。首次系统介绍了气囊式压力管理系统的工作原理及其主要结构设计，具体包括管线布局、钢制压力容器壳体、位于容器顶部封头上的接口组件和全部位于容器内的气囊等；同时对另外一种可行方案进行了分析。     

表面活性剂对多壁碳纳米管吸附Pb~(2+)的影响

多壁碳纳米管(MWNT)在吸附有毒气体和重金属离子方面具有极高的应用价值.针对MWNT对水溶液中Pb2+的净化吸附进行了研究,从吸附量,吸附速率、动力学角度考察了表面活性剂、Pb2+浓度对MWNT吸附Pb2+的影响.结果表明,司班-60、吐温-20、阿拉伯树胶等表面活性剂的加入,促进了MWNT在溶液中的分散,导致在Pb2+摩尔浓度为3～18 mmol/L的Lang-muir和Freundlich等温吸附方程中的吸附常数(K)变大,使得MWNT对Pb2+的吸附速率和平衡吸附量都得到提高;随着溶液中Pb2+浓度的增大,MWNT对其吸附量渐至饱和,随后由于Pb2+的位阻作用.吸附量下降;在这3种表面活性剂中,由于司班-60具有相对较小的分子量,其分散的MWNT在Pb2+摩尔浓度为14 mmol/L时,吸附量最大,为230 mg/g.     

四氯化钛精制除钒废弃物的综合利用

对四氯化钛铜丝除钒精制过程中产生的废弃物，采用酸碱联合法回收其中的铜和钒。考察了关键的碱处理及盐酸沉钒过程的影响因素。实验结果为：在碱处理溶液pH12．0—13．0，碱处理温度60℃，碱处理时间1h，沉钒溶液pH1．0～1．5，沉钒温度60℃，沉钒时间1h的条件下，铜和钒的回收率分别达到90％和75％以匕，获得的阴极铜和五氧化二钒的产品质量均达到国家标准。     

天津市滨海新区地震地质灾害评价与分区研究

收集了天津市滨海新区大量的工程地质勘察资料,针对滨海新区场地工程地质条件,从地震地质背景、历史震害的影响出发,依照相应规范和地质类比等方法,通过滨海新区活动断层影响、砂土液化、软土震陷的评判,探讨了滨海新区在未来强震作用下可能出现的地震地质灾害类型及空间分布特征。     

地震救援行动的影响因素分析

从探讨救援行动的概念和响应过程出发,在分析国内外相关资料的基础上,结合我国的实际情况,分析了影响地震救援行动的方面和因素,以及它们对救援行动可能产生的影响,以期为地震救援的理论和实践提供有益的补充。     

外源硅对不同pH水田土壤吸附铅的影响

通过等温吸附实验,研究了加硅对2种不同pH水田土壤吸附铅特性的影响。实验中用硝酸中和硅酸钠的碱性,各处理间钠离子和硝酸根离子的差异以硝酸钠补齐,消除了因硅酸盐的加入改变体系pH及伴随离子对土壤吸附铅可能产生的影响。结果表明,在本实验条件下,Langmuir方程、Freundlich方程和Temkin方程都能较好地描述不同硅浓度条件下两种土壤对铅的吸附特征,但以Freundlich模型为最优;加硅促进了酸性土壤对铅的吸附,抑制了碱性土壤对铅的吸附。     

Determination of total petroleum hydrocarbons (TPH) in agricultural soils near a petrochemical complex in Guangzhou,China

The total petroleum hydrocarbons (TPH) pollution in regional agricultural soils was investigated. Seventy soil samples collected from surface layers (0–20 cm) and horizons of five selected pedons in the vicinity of a petrochemical complex in Guangzhou, China were analyzed, and the vertical variation and spatial variability of TPH were evaluated. The TPH concentration in top soils around the petrochemical complex ranged from 1,179.3 to 6,354.9 mg kg^− 1, with the average of 2,676.6 mg kg^− 1. Furthermore, significant differences between land-use types showed that the TPH concentration in top soils was strongly influenced by accidental spills. Both the TPH trends in pedons and the identified hot-spot areas also showed that the accidental explosions or burning accidents were mainly responsible for the pollution. The results reported here suggest that the regular monitoring and inspection shall be conducted for safety and to avoid or minimize the accidents, and the effective measures should be taken to remediate the contaminated areas and to assure that the important industrialization of Guangzhou area would not mean human health risks near the petrochemical complex.