Trace elements in coal: Associations with coal and minerals and their behavior during coal utilization - A review

Trace elements such as mercury, arsenic and selenium present in coal are known to be of concern for public health. Coal-fired power plants have resulted in emission of several tons of TEs in environment. These elements mostly evaporate during combustion and condense either homogeneously as sub-micron ash or heterogeneously onto already existing fine ash. The coal-mineral and mineral-mineral associations play an important role in the formation of fine particles and in subsequent condensation of trace elements in various phases. Any retention of these elements in fly ash particles is strongly influenced by their association with other minerals in individual coal and mineral grains. Clean coal technology development is, therefore, a priority area for research and needs continuous improvements in increased efficiency and decreased pollutant emission. The paper will include trace elements in different coals from around the world. It will consider different modes of occurrences present in coals, the ash formation and evaporation of trace elements and emissions. The typical emissions from typical power stations will be presented. The paper will also review different approaches adopted in estimating the deportment of these elements. The paper at the end would discuss control strategies for reducing emissions and future directions.     

基于多智能体的编队协同空战战术规划

把编队看成一个多Agent系统,编队中的长机和僚机都看成是Agent。首先叙述了BDOTI-Agent的逻辑结构,然后提出基于多Agent的编队协同空战战术规划合作求解的方法,合作求解过程分为任务形成、合作产生、团队初步形成、任务分解、团队最终形成、角色指定和子任务分配、执行任务等7个阶段。最后举例说明了合作求解的过程。     

Catalytic Use of a Soluble Organoindium(III) Species for Allylation and Crotylation of Ketones with Boronates

The unprecedented use of a soluble organoindium species, indium(III) hexamethyldisilazide [In(III)(hmds)₃], for catalytic carbon carbon bond formations between ketones and boronates, is reported. Various functionalized tertiary homoallyl alcohols were generated easily in high yields. Remarkably, free hydroxy and primary amine functionalities proved to be tolerated. A rate acceleration and markedly improved diastereoselectivities were observed in the presence of methanol. Based on preliminary NMR experiments and the α‐selectivity with an α‐substituted boronate, we assume the in situ generation of reactive allylindium(III) species through catalytic boron‐to‐indium transmetalation.     

An Expeditious Copper‐Catalyzed Access to 3‐Aminoquinolinones, 3‐Aminocoumarins and Anilines using Sodium Azide

An efficient copper‐catalyzed in situ C(sp²) NH₂ bond formation to provide a range of 3‐aminoquinolin‐2(1H)‐ones and 3‐aminocoumarins from 3‐bromoquinolinones and 3‐bromocoumarins, respectively, has been achieved. The reaction conditions involve the use of copper powder as the catalyst, eco‐friendly ethanol as the solvent in the presence of pipecolinic acid as the ligand and ascorbic acid as the additive. The efficiency of this practical method was demonstrated in the synthesis of various anilines.     

内蒙古尚丹剖面阿木山组碳酸盐岩沉积环境及地球化学特征

尚丹剖面阿木山组,以结晶灰岩、生物灰岩为主,其中有丘状生物礁体,含丰富的腕足、棘皮类生物化石,生物碎屑滩规模大,主要发育碳酸盐岩台地相及台缘浅滩相。地球化学特征显示沉积环境为富氧的海相云坪半封闭超咸水环境。     

多孔介质中水合物生成与分解的电阻率性质

A new one-dimensional system for resistivity measurement for natural gas hydrate (NGH) exploitation is designed, which is used to study the formation and decomposition processes of NGH.The experimental results verify the feasibility of the measurement method, especially in monitoring the nucleation and growth of the NGH.Isovolumetric formation experiment of NGH is performed at 2 ℃ and 7.8 MPa.Before the NGH formation, the ini-tial resistivity is measured to be 4-7 Ω·m, which declines to the minimum value of 2-3 Ω·m when NGH begins to nucleate after the pressure is reduced to 3.3 MPa.As the NGH grows, the resistivity increases to a great extent, and finally it keeps at 11-13 Ω·m, indicating the completion of the formation process.The NGH decomposition ex-periment is then performed.When the outlet pressure decreases, NGH begins to decompose, accordingly, the resis-tivity declines gradually, and is at 5-9 Ω·m when the decomposition process ends, which is slightly higher than the resistivity value before the formation of NGH.The occurrence and distribution uniformity of NGH are determined by the distribution and magnitude of the resistivity measured on an one-dimensional sand-packed model.This study tackles the accurate estimation for the distribution of NGH in porous medium, and provides an experimental basis for further study on NGH exploitation in the future.     

螺杆灌注桩施工技术

螺杆灌注桩是在长螺旋挤压式灌注桩(含螺纹桩)基础上研制开发的新桩型,通过介绍螺杆灌注桩的基本原理、施工机械与设备、施工顺序与成桩工艺以及施工要点,说明了该桩型具有环保效果好、桩身质量可靠、承载能力较高、工程造价低、工期短、适用范围广等优点。     

浅谈福州城市的形成与旧城保护

本文从福州城市形成,提出了城市的改造和保护,并以人居环境科学的理论来探讨福州未来城市改造保护的战略思路。     

预应力管桩不宜施工的地层

本文通过具体的实例,结合自己多年工作经验以及工作中出现问题的处理方法,从不同的专业角度来看待、理解、探讨我们现在所学的专业中难以理解的现象,从中找出那些不适合预应力管桩施工的地层,或者说预应力管桩施工中可能出现难以施工的地层,如何去避免,去解决,或者从源头去消除,使之今后不在类似发生。     

分组多用户检测联盟模型与联盟形成算法研究

 以共享频谱的无线系统为背景,基于联盟博弈模型研究盲分组多用户检测性能与联盟结构的关系及最佳联盟形成算法.首先从系统指标角度提出了一种多用户检测可转移支付统计博弈模型;然后从用户偏好角度提出了一种不可转移支付模型;最后根据上述两种模型的研究结果,给出了最大化用户平均吞吐量的多用户检测联盟形成算法,并通过仿真验证了该算法的有效性.