换个视角谈地震观测改进与研究

自建国以来，中国的地震工作从无到有，地震队伍在不断壮大，经历了一个漫长发展的历程。而2008年5月12日下午2时28分发生在汶川的8．0级特大地震，造成了重大的伤亡和经济损失，引起地震工作者们的认真反思：多年来的地震工作布局有什么不足之处，哪些需要改进？很多问题值得思考，本文仅就以下三方面做一个讨论。     

Seasonal variability of polychlorinated biphenyls (PCBs) and polychlorinated diphenyl ethers (PBDEs) congener profiles in butter in Poland: Dietary risk evaluation

Various statistical methods have been employed to analyse in details seasonal diversification of polychlorinated biphenyl (PCB)/polybrominated diphenyl ether (PBDE) congener profiles found in butter fat. The variability of the PCB/PBDE congener profiles indicates the presence of various sources of the milk fat contamination. The obtained results suggest that the environmental chemical background has the highest share in the contamination sources pattern. Ion trap mass spectrometry coupled to high-resolution gas chromatography with semi-permeable membrane dialysis sample cleanup was used for determination of PCBs and PBDEs in milk fat. Determined butter fat PCB profiles were similar to the profiles characteristic for Aroclor 1254 technical mixture. Our data indicate that dietary intake of PCB/PBDE with milk and milk products may be estimated to be about 717.5 pg kg b.w.^?1 day^?1 for six-indicator PCBs, 0.329 (equivalent toxicity, TEQ) pg kg b.w.^?1 day^?1 for 12 DL PCBs and 50 pg kg b.w.^?1 day^?1 for PBDEs (sum of 14 congeners).     

水化氯铝酸钙对土壤铬的钝化修复及风险评估

本研究采集我国棕壤、红壤、黄壤、黑土和褐土5种典型土壤，制备成Cr （VI）浓度为80mg/kg的污染样品，首次应用极具潜力的层状双金属氢氧化物——水化氯铝酸钙对其进行钝化修复，并从土壤特定基本理化性质以及Cr的赋存形态、生态风险以及健康风险等方面对修复效果进行综合评价，对相关机理进行深入探讨，对使用成本进行简析.结果表明，水化氯铝酸钙可显著增加土壤pH值，并有效降低土壤Cr的活跃性、生态风险和健康风险；土壤Cr的活跃性降幅为59.09%~79.22%，生态风险降幅为14.17%~57.66%，在胃阶段和小肠阶段的健康风险（致癌风险）降幅分别为13.04%~63.04%和22.73%~56.60%.土壤Cr的赋存形态中，除了活跃态以外，修复前后均有部分不活跃态具有生态风险或健康风险.水化氯铝酸钙除了可将活跃态Cr转化到不活跃的沉淀态中，部分或完全地降低其生态风险或健康风险外，还能在一定程度上控制某些土壤中其余不活跃态Cr在毒性浸出实验或in vitro试验中的溶出.在相对最优使用量（m_Cr：m_{水化氯铝酸钙}=1：20）条件下，水化氯铝酸钙钝化修复1m³的Cr （VI）含量为80mg/kg的实际污染建设用地土壤，其试剂成本约为6.4元.作为新型Cr污染土壤钝化修复剂，水化氯铝酸钙有望为我国土壤环境质量和人群健康质量的改善做出贡献.     

Removal of arsenic from aqueous solution by two types of nano TiO2 crystals

Titanium dioxide (TiO₂) is a promising sorbent for As removal. There are two main and physico-chemically distinct polymorphs of TiO₂ in nature, namely anatase and rutile. Since the difference of arsenic removal by the two polymorphs of TiO₂ is now well known, study on the arsenic removal efficiency and the underlying mechanism is of great significance in developing new remediation strategies for As-polluted waters. Here batch experiments were carried out in combination with instrumental analysis of X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) to investigate the effects, influential factors and mechanisms of As removal from aqueous solution by two types of nano TiO₂ crystals. The adsorption behavior of anatase and rutile for As(V) and As(III) are well described by Freundlich equations. Anatase had higher As removal efficiency and adsorption capacity than rutile. Solution pH had no influence on the As adsorption of anatase TiO₂, whereas the As removal by rutile TiO₂ was increased by 7?C18% with pH from 4 to 10. Presence of accompanying anions such as phosphate, silicate, nitrate and sulfate, decreased the As(V) and As(III) removal by both crystals, with phosphate being the most effective. However, removal of As by rutile TiO₂ was greatly enhanced in the presence of divalent cations i.e. Ca²⁺ and Mg²⁺. Shading of light decreased the removal of As(V) and As(III) of anatase by 15.5% and 17.5%, respectively, while a slight increase of As removal was observed in the case of Rutile TiO₂. FT-IR characterization of As(V) or As(III)-treated nano TiO₂ crystals indicated that both Ti-O and As-O groups participated in As adsorption. Both FT-IR and XPS analysis demonstrated that As(III) was photooxidated into As(V) when adsorbed by anatase under the light condition. Thus, the effect of crystal types and light condition on As removal should be taken into consideration when nano TiO₂ is applied for As removal from water.     

Morphological characteristics of waste polyethylene/polypropylene plastics during pyrolysis and representative morphological signal characterizing pyrolysis stages

In this work, the morphological characteristics of waste polyethylene (PE)/polypropylene (PP) plastics during their pyrolysis process were investigated, and based on their basic image changing patterns representative morphological signals describing the pyrolysis stages were obtained. PE and PP granules and films were used as typical plastics for testing, and influence of impurities was also investigated. During pyrolysis experiments, photographs of the testing samples were taken sequentially with a high-speed infrared camera, and the quantitative parameters that describe the morphological characteristics of these photographs were explored using the “Image Pro Plus (v6.3)” digital image processing software. The experimental results showed that plastics pyrolysis involved four stages: melting, two stages of decomposition which are characterized with bubble formation caused by volatile evaporating, and ash deposition; and each stage was characterized with its own phase changing behaviors and morphological features. Two stages of decomposition are the key step of pyrolysis since they took up half or more of the reaction time; melting step consumed another half of reaction time in experiments when raw materials were heated up from ambient temperatures; and coke-like deposition appeared as a result of decomposition completion. Two morphological signals defined from digital image processing, namely, pixel area of the interested reaction region and bubble ratio (BR) caused by volatile evaporating were found to change regularly with pyrolysis stages. In particular, for all experimental scenarios with plastics films and granules, the BR curves always exhibited a slowly drop as melting started and then a sharp increase followed by a deep decrease corresponding to the first stage of intense decomposition, afterwards a second increase – drop section corresponding to the second stage of decomposition appeared. As ash deposition happened, the BR dropped to zero or very low values. When impurities were involved, the shape of BR curves showed that intense decomposition started earlier but morphological characteristics remained the same. In addition, compared to parameters such as pressure, the BR reflects reaction stages better and its change with pyrolysis process of PE/PP plastics with or without impurities was more intrinsically process correlated; therefore it can be adopted as a signal for pyrolysis process characterization, as well as offering guide to process improvement and reactor design.     

基于物资分类的煤炭企业供应商选择研究

从利润影响度、市场供应风险、需求稳定性对煤炭物资分类,针对筛选出的战略波动型物资,构建由7个一级指标、16个二级指标组成的多层次多属性供应商选择指标体系。结合实例,采用改进的三标度层次分析法确定指标权重,运用PROMETHEE-II法计算各供应商的净流量值对其排序,得到最终决策。整个决策过程可操作性强,对煤炭企业供应商选择有一定的指导意义。     

水污染第三方治理机制中第三方的刑事责任

"环境污染第三方治理"是党和政府顺应时代发展提出的治污新模式,这为我国水污染的治理指明了新方向。水污染第三方治理机制不仅在制度上是个创新,在法律层面也提出了新的要求,特别是在规制第三方的刑事责任方面。要明确第三方成为新的责任主体,在认定责任的归责原则上适用相对严格责任原则,在责任承担的具体方式上适用"双罚制"和罚金刑,为水污染第三方治理机制的引入奠定良好的法律基础。     

A double‐edged sword: The moderating role of conscientiousness in the relationships between work stressors,psychological strain,and job performance

Although conscientiousness was commonly viewed as a type of personal resource to help individuals reduce strain or mitigate the impacts of stressors, empirical research demonstrated mixed results. Based on the personal resource allocation perspective, we posited that rather than functioning as personal resource per se, conscientiousness may act as a key factor influencing how individuals allocate their personal resources. The current study examined the moderating roles of conscientiousness in the relationships that work stressors (i.e., challenge stressors and hindrance stressors) have with employee psychological strain and job performance by using multi‐source, time‐lagged data collected from 250 employees working at two companies. The results showed that both challenge stressors and hindrance stressors were positively related to psychological strain. Conscientiousness moderated the relationships between both stressors and psychological strain, such that the positive relationships were stronger for individuals with high conscientiousness. Conscientiousness also moderated the relationship between challenge stressors and performance, such that the relationship was positive for individuals with high conscientiousness but negative for those with low conscientiousness. Altogether, the findings suggest that conscientiousness acts as a double‐edged sword that both promotes performance and exacerbates the stress reaction of employees when they are confronted with stressful situations. Copyright © 2014 John Wiley & Sons, Ltd.     

贵州省典型矿区土壤重金属污染对蚯蚓的毒性效应评估

选取我国贵州省某矿区典型的重金属复合污染土壤开展28 d慢性毒性暴露试验,以蚯蚓体内2种抗氧化酶活性——过氧化氢酶(CAT)和超氧化物歧化酶(SOD)、8-羟基脱氧鸟苷(8-ODHG)和金属硫蛋白(MT)含量为生物指标,评估了以上生物指标与土壤重金属含量的相关性,探讨该研究方法用于矿区土壤重金属生态风险评估的可行性。结果表明,CAT和SOD在暴露周期内均出现先诱导后抑制的动态响应过程,表明蚯蚓通过提高CAT和SOD的活性来清除机体因污染胁迫而产生的自由基,以适应环境变化,在毒性缓解后,蚯蚓体内代谢产物的积累抑制了抗氧化氢酶活性,CAT和SOD活性下降并趋于稳定。暴露于重金属污染亚致死浓度时,蚯蚓体内的8-OHDG含量随着暴露时间的延长显著降低,随着暴露浓度的增加,损伤存在由低到高的转变。在28 d暴露周期内,蚯蚓体内MT在重金属胁迫下发挥了解毒作用,MT含量在蚯蚓暴露后第7天增加,随后逐渐降低。本文基于生物毒性试验综合评估了矿区典型重金属污染土壤的生态风险,研究结果对指导重金属复合污染土壤的修复与再利用具有重要意义。     

基于ICA/MNF变换的高分影像滑坡灾害检测方法研究

快速准确地从灾后影像中提取出受灾区域对于灾后救援具有重要意义。鉴于现有提取方法过度依赖滑坡在影像中的光学、纹理等特征的问题,研究了一种结合独立成分分析(ICA)与最小噪声比率变换(MNF)的变化检测方法,以单一时相的影像为基础,运用基于负熵最大化的Fast-ICA算法分离出两个时相影像相互正交的独立成分,并构建对应独立成分的差异影像,最后用最小噪声比率变换实现分布于各个差异影像上变化信息的集中,应用直方图阈值法得到了最终的滑坡灾害信息。选取了滑坡灾害前后两时相的高分辨率遥感影像数据进行实验,结果证实了方法的可行性。