煤与瓦斯共采在错层位巷道布置中的机理研究及应用构想

为了完善现有煤与瓦斯共采技术，创新煤与瓦斯共采方法，对错层位巷道布置下的煤与瓦斯共采系统展开研究，利用相似模拟试验，分析错层位巷道布置覆岩运动情况，预测其开采围岩裂隙发育和瓦斯运移形式，提出了创新煤与瓦斯共采技术构想。研究结果表明:采空区覆岩三带高度随接续工作面的增加而增大，相邻采空区垮落矸石压实区呈现“O-L-O”形变化，多个相邻采空区覆岩出现大“O”形圈裂隙带；相邻采空区内瓦斯可实现相互运移，大“O”形圈裂隙带内赋存大量瓦斯气体；研究提出了地面钻井抽采瓦斯、走向高位瓦斯抽采巷和外错尾巷穿层钻孔3种煤与瓦斯共采技术，比传统巷道布置情况下的煤与瓦斯共采技术在安全、经济等方面更具优势。     

Purification of water contaminated with Hg using horizontal subsurface constructed wetlands

As a global pollutant, Hg (Hg) since the turn of the last century has received increased attention. Decreasing the emission of Hg into the food chain and the atmosphere is an effective way to reduce the Hg damage. The current study provided information about pilot-scale horizontal subsurface flow (HSSF) constructed wetlands (CWs) to remove different Hg species in polluted water. Synthetic wastewater was fed to two HSSF CWs, one was planted with Acorus calamus L and the other was unplanted as a control. The total Hg (THg), dissolved Hg (DHg), and particulate Hg (PHg) from five sites along the HSSF CWs were analyzed to describe the process of Hg removal. Results show that the CWs have high removal efficiency of Hg which is more than 90%. The removal efficiencies of THg and DHg from the unplanted CW were 92.1?±?3.6% and 72.4?±?13.1%, respectively. While, the removal efficiencies of THg and DHg in planted CW were 95.9?±?7.5% and 94.9?±?4.9%, which were higher than that in blank CW. The PHg was mainly removed in the first quarter of the CWs, which was also revealed by the partition coefficient K_d. To a certain extent, the effect of plants depends on the hydraulic retention time (HRT). The results in the current study show the potential of the HSSF-CWs for restoration from Hg-contaminated water.

     

Health risk assessment of heavy metals in Cyprinus carpio (Cyprinidae) from the upper Mekong River

The purposes of this research are to quantify the concentration of heavy metals (Zn, Cu, As, Pb, Cd, and Hg) in the water and fish tissues of common carp (Cyprinus carpio) in the upper Mekong River and to thereby elucidate the potential dietary health risks from fish consumption of local residents. Surface water and fish tissues (gill, muscle, liver, and intestine) from four representative sample areas (influence by a cascade of four dams) along the river were analyzed for heavy metal concentrations. Results revealed that the levels of heavy metals in fish were tissue-dependent. The highest Cu and As levels were found in the liver; the highest Zn and Pb levels occurred in the intestine, and the highest Hg level was found in the muscle. The total target hazard quotient (THQ) value for residents is > 1 for long-term fish consumption, and local residents are, therefore, exposed to a significant health risk. Results from the current study provide an overall understanding of the spatial and tissue distribution of heavy metals in water and fish body along the upper Mekong River under the influence of cascade dams and highlight the potential health risk of As for the local residents of long-term fish consumption.

     

The associations of air pollution exposure during pregnancy with fetal growth and anthropometric measurements at birth: a systematic review and meta-analysis

Environmental Science and Pollution Research - Fetal growth has been demonstrated to be an important predictor of perinatal and postnatal health. Although the effects of maternal exposure to air...     

走向工作面贯通上山与支架快速回撤技术

针对走向工作面停采线与上山之间的护巷煤柱造成煤炭损失，支架回撤工艺复杂、巷道掘进量大等问题，提出走向工作面贯通上山与支架快速回撤技术。工作面贯通采区上山，利用上山回撤支架。在贯通前，利用压力拱模型分析剩余煤柱应力变化规律，并结合极限平衡区公式，确定让压煤柱为8 m；对贯通前基本顶合理断裂位置、让压调节机制、末采阶段采高进行了分析确定，并采取上山巷内补强支护及挂绳铺网措施。贯通上山后，首先利用支架对上山留巷，完成留巷后，利用上山回撤支架，先将上部端头3架逆时针旋转90°作为掩护架，在对剩余支架逐架回撤时，3个掩护架呈现台阶型。提出的技术取消了护巷煤柱及回撤通道，提高了煤炭采出率，减少了巷道掘进量，简化了回撤工艺。     

分层开采工艺对地表沉降的影响研究

分层开采是厚煤开采的经典工艺,这种工艺对地表沉降的影响比较复杂。通过测试原岩物理力学参数,利用有限元软件flac3D对分层和一次采全高时地表沉降进行了数值模拟。结果表明,如果采高较小,砌体梁距煤层较近,且采完上分层后长时间停采,给顶板再生留足时间,分层开采较一次采全高对地表沉降影响要小。     

The accounting method and application of CO2 emissions responsibility by the electricity sector at the provincial level in China

When accounting the CO₂ emissions responsibility of the electricity sector at the provincial level in China,it is of great significance to consider the scope of both producers’ and the consumers’ responsibility,since this will promote fairness in defining emission responsibility and enhance cooperation in emission reduction among provinces.This paper proposes a new method for calculating carbon emissions from the power sector at the provincial level based on the shared responsibility principle and taking into account interregional power exchange.This method can not only be used to account the emission responsibility shared by both the electricity production side and the consumption side,but it is also applicable for calculating the corresponding emission responsibility undertaken by those provinces with net electricity outflow and inflow.This method has been used to account for the carbon emissions responsibilities of the power sector at the provincial level in China since 2011.The empirical results indicate that compared with the production-based accounting method,the carbon emissions of major power-generation provinces in China calculated by the shared responsibility accounting method are reduced by at least 10%,but those of other power-consumption provinces are increased by 20% or more.Secondly,based on the principle of shared responsibility accounting,Inner Mongolia has the highest carbon emissions from the power sector while Hainan has the lowest.Thirdly,four provinces,including Inner Mongolia,Shanxi,Hubei and Anhui,have the highest carbon emissions from net electricity outflow- 14 million t in 2011,accounting for 74.42% of total carbon emissions from net electricity outflow in China.Six provinces,including Hebei,Beijing,Guangdong,Liaoning,Shandong,and Jiangsu,have the highest carbon emissions from net electricity inflow- 11 million t in 2011,accounting for 71.44% of total carbon emissions from net electricity inflow in China.Lastly,this paper has estimated the emission factors of electricity consumption at the provincial level,which can avoid repeated calculations when accounting the emission responsibility of power consumption terminals（e.g.construction,automobile manufacturing and other industries）.In addition,these emission factors can also be used to account the emission responsibilities of provincial power grids.     

Precursors and potential sources of ground-level ozone in suburban Shanghai

• Air masses from Zhejiang Province is the major source of O₃ in suburban Shanghai. • O₃ formation was in VOC-sensitive regime in rural Shanghai. • O₃ formation was most sensitive to propylene in rural Shanghai. A high level of ozone (O₃) is frequently observed in the suburbs of Shanghai, the reason for this high level remains unclear. To obtain a detailed insight on the high level of O₃ during summer in Shanghai, O₃ and its precursors were measured at a suburban site in Shanghai from July 1, 2016 to July 31, 2016. Using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model and concentration weighted trajectories (CWT), we found that Zhejiang province was the main potential source of O₃ in suburban Shanghai. When the sampling site was controlled by south-western winds exceeding 2 m/s, the O₃-rich air masses from upwind regions (such as Zhejiang province) could be transported to the suburban Shanghai. The propylene-equivalent concentration (PEC) and ozone formation potential (OFP) were further calculated for each VOC species, and the results suggested that propylene, (m+p)-xylene, and toluene played dominant roles in O₃ formation. The Ozone Isopleth Plotting Research (OZIPR) model was used to reveal the impact of O₃ precursors on O₃ formation, and 4 base-cases were selected to adjust the model simulation. An average disparity of 18.20% was achieved between the simulated and observed O₃ concentrations. The O₃ isopleth diagram illustrated that O₃ formation in July 2016 was in VOC-sensitive regime, although the VOC/NO_x ratio was greater than 20. By introducing sensitivity (S), a sensitivity analysis was performed for O₃ formation. We found that O₃ formation was sensitive to propylene, (m+p)-xylene, o-xylene and toluene. The results provide theoretical support for O₃ pollution treatment in Shanghai.     

盐度对模拟餐厨垃圾发酵液产聚羟基脂肪酸酯工艺的影响

利用餐厨垃圾发酵液生产聚羟基脂肪酸酯(PHA)可以在废物处理的同时实现有价资源回收。为探究发酵液中盐分对产PHA菌群富集过程的影响,以模拟餐厨垃圾发酵液为底物,研究了盐度存在下污泥理化性质、富集过程主要指标及菌群PHA合成能力等变化。结果表明,未经盐度富集的菌群易受到盐度抑制,在15 g·L~(-1)的盐度条件下,污泥PHA最大合成量可降至39.9%。富集过程中盐度的增加有利于污泥沉降性的提升,低盐度(5 g·L~(-1))下菌群分泌胞外聚合物量最多,达49.8 mg·g~(-1)(以VSS计),对菌群保护能力最强。不同盐度条件下的富集系统皆能保持较好的生态选择压力,但盐度对微生物生长的抑制随着浓度的增大而增强。经过盐度存在下长期富集后的污泥,在高盐度(10、15 g·L~(-1))底物条件下,仍能获得较高的PHA最大合成能力,但其较低的生长活性不利于最终PHA产量的提升,短期富集下,高盐度会抑制PHA的合成;而低盐度(5 g·L~(-1))有助于提高PHA合成能力,最高达50.5%。     

Larval and Juvenile Fish Assemblage Structure of Inshore Habitats in the Middle Reaches of Li River,China: Spatial and Temporal Patterns in Relation to Abiotic Factors

To evaluate the effect of abiotic factors on larval and juvenile fish assemblage in shallow waters of middle reaches of Li River, Guilin, China. Samplings were taken monthly at 7 stations in the mainstream and 2 stations in 3 tributaries from May 2014 to April 2015. Synchronously, temperature, pH, turbidity, conductivity, dissolved oxygen rainfall and discharge were obtained. In all, 11.886 larval and juvenile fish from 18 species belonging to 8 families, 16 genera was captured. Principal Component Analysis (PCA) showed obvious significant difference between the environmental variables across sampling areas and months. The results of Canonical Correspondence Analysis (CCA) indicated that water temperature, turbidity, discharge and rainfall were dominant factors on larval and juvenile fish assemblage.