基于Matlab优化工具箱的煤巷顶板锚杆支护结构可靠性分析

针对煤巷围岩力学参数中有许多为随机变量的特征,根据围岩稳定性极限状态方程,应用工程结构可靠性理论,分析煤巷顶板锚杆支护结构的可靠性,建立基于Matlab优化工具箱的可靠度计算模型。该法编程简单,计算速度快,精度高,程序通用性强,是一种计算煤巷锚杆支护结构可靠度的有效方法,并且分析该法计算结构可靠度的适用条件,建立了巷道顶板支护参数与可靠度的关系曲线,为煤巷锚杆支护参数设计和优化提供了科学依据。     

多元混合气爆炸极限的非线性预测研究

根据混合气的爆炸极限与混合气各成分的体积浓度之间具有非线性关系的特点,笔者提出采用神经网络非线性方法来计算含有H2,CH4和CO的多元混合气体的爆炸极限。在模型中,H2,CH4和CO的体积浓度作为输入,爆炸上限和下限作为输出。计算结果表明,该非线性模型预测混合气爆炸下限和上限的最大相对误差为3.90%,3.57%,而模型预测值与计算值的相关系数分别为0.971,0.981;非线性模型的预测结果要好于偏最小二乘回归的预测结果。当H2,CO,CH4在混合气中的体积浓度给定时,非线性模型能够准确预测混合气的爆炸极限。     

污染防治最佳可行技术的评估及应用研究

污染防治最佳可行技术（BAT）是污染综合防治与控制工作中的一个重要组成部分,对实现污染减排目标以及从整体上实现高水平的环境保护具有重要作用。介绍了BAT在污染物排放限值制定中的应用,以及国内外选择和确立BAT的程序及方法。由于基于技术的选择涉及多方面因素,在技术评估过程中尚有许多问题有待解决。针对BAT技术评估过程中技术的最佳组合难以确定,以及经济可行性难以量化这两方面问题,介绍了国内外学者的相关研究。     

油指纹鉴别中诊断比值的重复性限比较法

诊断比值是油指纹鉴别中非常重要的鉴别指标,本文基于重复性限这一经典的统计学概念,详细介绍了利用重复性限进行溢油鉴别中诊断比值比较的方法,包括方法原理、诊断比值的评价及鉴别原则,并以某原油及其风化样品以及2种不同原油的油指纹鉴别为例,说明了此种方法的有效性,这对于提高基于油指纹的溢油鉴别准确度和效率将有重要意义.     

甲烷-煤尘复合体系中煤尘爆炸下限的实验研究

在3.2 L的燃烧管道中,采用小能量的高压点火装置,通过改变甲烷体积分数、煤尘种类与粒径,研究了甲烷-煤尘复合体系中煤尘爆炸下限的变化规律.研究结果表明,在本文实验条件下,甲烷-煤尘混合物中甲烷体积分数的增加能明显降低煤尘的爆炸下限.对于煤尘粒径小于42 μm煤样A,当甲烷体积分数从1.8%增加到2.2%时,煤尘的爆炸下限相应从30 g/m3下降到6.25 g/m3.煤尘的爆炸下限也随着煤尘中挥发分含量的增加而降低.煤尘粒径对其爆炸下限的影响较弱.实验结果与文献中高能量化学药头点火的测试结果进行比较表明,甲烷对煤尘爆炸下限的影响趋势并不随着点火源能量的改变而改变.     

Improved electrospray design for aerosol generation and flame propagation analysis

Although the hazards of aerosol fires and explosions have been studied for decades the data for aerosol flame propagation is still scarce. Additionally there is a lack of standard techniques and measurement apparatus, which impedes the development of optimal aerosol hazard mitigation measures. The focus of this study is development of an improved aerosol electrospray device for the generation of high quality aerosol data. The goal is achieved through higher nozzle packing, precise nozzle and mesh hole alignment and adding two ground meshes. In addition to a flat ground mesh, the utilization of a cylindrical ground mesh demonstrated improved confinement and guidance of droplets. Duratherm 600, heat transfer fluid, was examined to demonstrate the modified electrospray device capabilities as compared to previous design. Results show the modified electrospray can produce more uniform droplets, more even test chamber dispersion, smaller droplet size and higher concentration aerosol, which is essential to study aerosol flame propagation. Accordingly, the results of aerosol flame speed tests for the improved design were more reproducible. Moreover, it was found that a traditional propane pilot flame was unable to ignite the smaller aerosol droplet size due to the strong turbulence generated by the open flame. However, by careful modification of the pilot flame length, the turbulence decreased dramatically and the small droplet size aerosol can be tested.     

赣南稀土区生物效应研究——稀土日允许摄入量

通过对赣南稀土区食谱中稀土分布调查,人体某些健康项目调查及结合动物实验结果分析,估算得稀土区成人的稀土（REO）日摄入量为6.0～6.7mg,属不安全量,而对照区成人日摄入量为3.3mg为安全量,据此分析比较,认为成人日允许摄入量定为4.2mg较妥,约为前人由动物实验外推的允许日摄入量14～24mg的五分之一。本研究对预测稀土远期环境风险有一定的参考价值,并提出应着手研究稀土污染治理问题。     

Flammability hazard analysis of imidazolium-based ionic liquid binary mixtures under high temperatures

Ionic liquid (IL) mixtures are promising because they can optimize the involved properties according to industrial needs. It has already been demonstrated that IL flammability is due mainly to IL decomposition generating flammable substances. Four different ILs, 1-Butylimidazolium tetrafluoroborate ([BIM][BF₄]), 1-butylimidazolium nitrate ([BIM][NO₃]), 1-butyl-3-methylimidazolium tetrafluoroborate([BMIM][BF₄]), and 1-butyl-3-methylimidazolium nitrate ([BMIM][NO₃]), were selected as the parent salts to form the different imidazolium-based IL binary mixtures. These mixtures were tested via isothermal thermogravimetric analyzer (TGA) at different temperatures (120, 150, 180, 210, and 240 °C), then tested by the flash point analyzer after isothermal heating pretreatment at the above temperatures. Results show that the mixtures' flash point values decrease with the heating temperature increase. Vaporization of the IL mixtures’ decomposition products results in a higher concentration of flammable gases and a flash point decrease, which lead to the flammability hazard increasing. Moreover, results show that the flash points of the studied binary imidazolium IL mixtures are more similar to those of the more unstable IL in their parent ILs. Also, the flammability hazard of IL binary mixtures may obviously increase under the high temperature environment for a long time.     

基于Hoek Brown强度准则深埋隧道掌子面稳定性分析*

为了研究孔隙水压力作用下深埋隧道掌子面的稳定性,构建了深埋盾构隧道的二维刚性有限平动多块体的破坏模式,并引入了Hoek Brown强度准则。利用极限分析得到掌子面前方土体的内部耗散能和外力做的功,利用Hoek Brown强度准则推导得到极限支护力的目标函数,通过MATLAB数值软件的规划求解得到支护力的解,和既有文献中的成果对比,2种方法得到解的最大误差为6.7%,验证了Hoek Brown强度准则的有效性。对各个岩体参数下深埋隧道掌子面极限支护力的变化规律进行分析,结果表明:深埋隧道掌子面前方的极限支护力随着扰动因子D和孔隙水压力系数ru的增大而增大,随着地质强度指标GSI和参数mi的增大而减小;破坏范围随着参数mi和孔隙水压力系数ru的增大而减小,而随着地质强度指标GSI和扰动因子D的增大而增大。研究结果可为岩质地层中深埋盾构隧道掌子面支护力的设计提供理论依据。