吸力式桶形基础多桶组合结构承载力特性研究

海洋采油平台结构中一般采用多桶组合基础型式,然而迄今对多桶组合结构尚缺乏理论分析和实验研究。本文针对我国第一座吸力式桶形基础采油平台CB20B,基于单桶基础在复合加载模式下的承载力特性,建立了双桶、四桶组合基础的三维有限元数值计算模型,探讨了对称多桶基础结构与单桶基础结构的承载力特性之间的相互关系,阐述了不同桶间距的多桶组合结构地基破坏机制,为工程设计提供参考依据。     

Xα21基因导入水稻及转基因植株的鉴定

以水稻愈伤组织为受体、质粒pCXK1301为Xα21基因供体,用农杆菌EHA105和PDS－1000／He基因枪转化受体,经Hyg浓度梯度筛选,获得一些转基因水稻植株,GUS检测、PCR扩增和Southern杂交分析表明,报告基因（GUS）、选择标记基因（Hyg^r）和抗白叶枯病基因Xα21都已整合入转化水稻基因组中,Southern杂分析显示了Xα21基因在转化水稻基因组中整合的拷贝数。田间接菌鉴定表现抗白叶枯病。     

Mapping afforestation and deforestation from 1974 to 2012 using Landsat time-series stacks in Yulin District, a key region of the Three-North Shelter region, China

The Three-North Shelter Forest Program is the largest afforestation reconstruction project in the world. Remote sensing is a crucial tool to map land use and land cover change, but it is still challenging to accurately quantify the change in forest extent from time-series satellite images. In this paper, 30 Landsat MSS/TM/ETM+ epochs from 1974 to 2012 were collected, and the high-quality ground surface reflectance (GSR) time-series images were processed by integrating the 6S atmosphere transfer model and a relative reflectance normalization algorithm. Subsequently, we developed a vegetation change tracking method to reconstruct the forest change history (afforestation and deforestation) from the time-series Landsat GSR images based on the integrated forest z-score (IFZ) model by Huang et al. (2009a), which was improved by multi-phenological IFZ models and the smoothing processing of IFZ data for afforestation mapping. The mapping result showed a large increase in the extent of forest, from 380,394 ha (14.8 % of total district area) in 1974 to 1,128,380 ha (43.9 %) in 2010. Finally, the land cover and forest change map was validated with an overall accuracy of 89.1 % and a kappa coefficient of 0.858. The forest change time was also successfully retrieved, with 22.2 % and 86.5 % of the change pixels attributed to the correct epoch and within three epochs, respectively. The results confirmed a great achievement of the ecological revegetation projects in Yulin district over the last 40 years and also illustrated the potential of the time-series of Landsat images for detecting forest changes and estimating tree age for the artificial forest in a semi-arid zone strongly influenced by human activities.     

Development of a multi-criteria index ranking system for urban runoff best management practices (BMPs) selection

Low impact development best management practices (LID-BMPs) are considered to be cost-effective measures for mitigating the water quantity and quality impact of urban runoff. Currently, there are many types of LID-BMPs, and each type has its own intrinsic technical and/or economical characteristics and limitations for implementation. The selection of the most appropriate BMP type(s) for a specific installation site is therefore a very important planning step. In the present study, a multi-criteria selection index system (MCIS) for LID-BMP planning was developed. The selection indexes include 12 first-level indices and 26 second-level indices which reflect the specific installation site characteristics pertaining to site suitability, runoff control performance, and economics of implementation. A mechanism for ranking the BMPs was devised. First, each individual second-level index was assigned a numeric value that was based on site characteristics and information on LID-BMPs. The quantified indices were normalized and then integrated to obtain the score for each of the first-level index. The final evaluation scores of each LID-BMP were then calculated based on the scores for the first-level indices. Finally, the appropriate BMP types for a specific installation site were determined according to the rank of the final evaluation scores. In order to facilitate the application of the MCIS BMP ranking system, the computational process has been coded into a software program, BMPSELEC. A case study demonstrating the MCIS methodology, using an LID-BMP implementation planning at a college campus in Foshan, Guangdong Province, is presented.     

Robust Regression with Data-Dependent Regularization Parameters and Autoregressive Temporal Correlations

We introduce robust procedures for analyzing water quality data collected over time. One challenging task in analyzing such data is how to achieve robustness in presence of outliers while maintaining high estimation efficiency so that we can draw valid conclusions and provide useful advices in water management. The robust approach requires specification of a loss function such as the Huber, Tukey’s bisquare and the exponential loss function, and an associated tuning parameter determining the extent of robustness needed. High robustness is at the cost of efficiency loss in parameter loss. To this end, we propose a data-driven method which leads to more efficient parameter estimation. This data-dependent approach allows us to choose a regularization (tuning) parameter that depends on the proportion of “outliers” in the data so that estimation efficiency is maximized. We illustrate the proposed methods using a study on ammonium nitrogen concentrations from two sites in the Huaihe River in China, where the interest is in quantifying the trend in the most recent years while accounting for possible temporal correlations and “irregular” observations in earlier years.     

Microbial community composition and electricity generation in cattle manure slurry treatment using microbial fuel cells: effects of inoculum addition

Environmental Science and Pollution Research - Microbial fuel cell (MFC) is a sustainable technology to treat cattle manure slurry (CMS) for converting chemical energy to bioelectricity. In this...     

中国废纸回收系统的现状及展望

分析了我国废纸回收行业的发展现状及存在问题,提出了提高我国废纸回收和利用率的具体措施,并以江苏省为例,介绍了其建设废纸回收体系的具体做法.     

Photodegradation of quinestrol in waters and the transformation products by UV irradiation

Quinestrol is synthetic estrogen used in contraceptive and hormone replacement therapy and occasionally for treating breast cancer and prostate cancer. It can make its way into the environment through sewage discharge and waste disposal produced by human excretions. In this study, the photodegradation kinetics of quinestrol in various conditions was investigated by UV and solar irradiation. The affecting factors were studied including concentration of hydrogen peroxide, different water types, and the initial concentrations of quinestrol. Concurrently, the transformation products and presumed pathways of quinestrol in distilled water by UV irradiation were identified and proposed. The results showed that the degradation of quinestrol in both irradiation conditions followed the pseudo-first-order kinetics. More rapid degradation was observed by UV irradiation (k = 0.018 min⁻¹) than solar irradiation (k = 0.004 h⁻¹), and the photodegradation rate of quinestrol depended on the concentration of hydrogen peroxide, the initial concentration of quinestrol and water types. The transformation products of quinestrol in distilled water were identified by gas chromatography/mass spectrometry. When exposed to UV irradiation, quinestrol in aqueous solution was rapidly degraded, giving at least ten photodegradation products. The chemical structures of ten degradation products were identified on the basis of mass spectrum interpretation and literature data.     

Comparison of homologous and heterologous formats in nanocolloidal gold-based immunoassays for parathion residue determination

The effectiveness of homologous and heterologous formats in a nanocolloidal gold-based immunoassay for pesticide residue determination was investigated. Parathion, one of the most toxic organophosphorus pesticides, was used as the target analyte. One-step homologous and heterologous test strips based on a nanocolloidal gold-labeled monoclonal antibody were developed for the rapid detection of parathion residues. The results showed that the heterologous format was more effective than the homologous format, being more sensitive, more specific to parathion and more tolerant of matrix interferences. The best competitive hapten was found to have a moderate heterology and the opposite electronic distribution to the immunizing hapten. The detection limits for parathion using the preferred heterologous strip were 1 μg/L in water samples and 5 μg/kg in soil and food samples.     

VFAs、TOC及COD作为生物除磷能力指标的探讨

在实际生活污水的处理中,研究了通过A/O运行模式对生物除磷过程中磷的变化情况及在厌氧释磷过程中COD、TOC与VFAs变化之间的关系。结果表明,在厌氧释磷过程中VFAs的变化更能准确地反映系统内释磷进程,实际生活污水中能直接用于磷释放的有机物含量占COD的13.33%,并且释放1 mg P所需VFAs为1.401 mg,此值明显低于前期研究结果。通过对COD、TOC和VFAs 3种组分的分析,可将实际生活污水中的有机底物分为3类:易生物降解含碳有机物、难降解的含碳有机物和水中存在的无机性还原物质,含量分别占COD的13.33%、31.7%和54.97%,其中只有13.33%的含量对生物释磷有直接作用,并可对实际生活污水除磷有指导意义。