广州市交通主干道空气中苯系物的测量

为了研究广州市道边空气中苯系物的污染状况,利用差分吸收光谱(DOAS)系统于2010年11～12月广州亚运会期间对广州市荔湾区黄沙大道道边空气中的苯系物(苯、甲苯、二甲苯等)及常规污染物NO2、O3等进行了监测.结果表明,在整个测量期间,苯系物在夜间显示了较高的浓度值,苯的平均浓度为15.9μg·m-3、甲苯为61.3μg·m-3、对-二甲苯为6.5μg·m-3、间-二甲苯为16.9μg·m-3、苯酚为0.88μg·m-3.甲苯与苯的平均浓度与国内其他城市的平均水平较为接近,两者的比值变化范围在1.2～6.16.通过比对甲苯与苯的相关性,在整个测量期间内其相关系数为0.86,在浓度值较高时段,其相关系数达到0.985,表明在该区域苯与甲苯存在同源性;以甲苯为例,分析其与CO的相关性,相关系数为0.78,表明交通排放是苯、甲苯的一个主要来源.结合风速风向等气象数据的分析得出气象条件是影响苯系物污染物浓度水平的一个重要因子,并给出了可能的点污染源.     

基于热爆炸理论的煤燃点确定及动力学分析

为准确判断煤燃点,提高煤自燃灾害防治能力,依据热爆炸理论,结合煤自燃过程放热曲线,将煤自燃升温过程中微分热流曲线上第1处极小值点作为煤的燃点,计算煤着火前后放热过程动力学参数变化.结果表明:随升温速率增加,煤自燃反应放热过程逐渐向高温区域移动,煤燃点逐渐增大,反应的活化能逐渐减小;同一升温速率下燃点之后煤的活化能增大;...     

DOAS监测排放烟气浓度时谱线漂移处理方法研究

差分吸收光谱法(DOAS)是利用气体在紫外可见光波段对光具有选择吸收的特性来测量气体浓度的一种方法。DOAS法连续监测系统的核心是软件部分,由于吸收谱线漂移现象的存在,光谱解析算法的改进对污染气体浓度的计算带来很大的影响。基于DOAS法研究监测排放烟气浓度时谱线漂移对浓度计算的影响,并提出将相关函数和相关系数结合参与浓度计算,实验的结果表明,可以有效地减小谱线漂移时浓度计算的误差。     

基于差分进化-NM单纯形法的危化品泄漏源定位

为确定危化品泄漏源的强度和位置,提出1种基于DE-NM算法的危化品泄漏源定位方法,以监测浓度与扩散模型计算浓度的误差作为优化目标,在差分进化过程中每隔一定代数执行单纯形法,使得二者误差最小的源强和位置即为最优定位结果。研究结果表明：DE-NM算法能够快速有效地反算出泄漏源的强度和位置,满足应急响应的要求;同时,能够避免DE算法的过早收敛,以及NM算法对初值敏感的问题,有效降低单一算法对定位结果精度造成的不利影响。     

机场旅客行李托运差异化安检模式安全性研究

为减少因违禁物品托运引发的不安全事件,基于原有安检模式,提出行李托运差异化安检模式,结合搜索-决策检查模型,建立系统错误报警及错误通过率公式,得到行李托运安检系统准确度-速度变化规律.结果表明:差异化安检模式一方面提高系统安全性,另一方面提升安检效率,节约安检资源.研究结果可为机场调整安检策略提供参考.     

应用全差示光度法测定水和废水中的微量氰化物

在ｐＨ８０时,ＣＮ－与３甲基１苯基５吡唑啉酮、吡啶及氯胺Ｔ反应形成稳定的蓝色产物,最大吸收波长为６１７ｎｍ,表观摩尔吸收系数为１２×１０５Ｌ／ｍｏｌ·ｃｍ。实验了采用全差示光度法测定微量氰化物的条件。通过蒸馏富集,建立了改进的吡唑啉酮法测定氰化物的分析方法,并对实际样品进行了测定。本方法的检出限为０００１ｍｇＣＮ－／Ｌ,检测范围为０００１～０２５ｍｇＣＮ－／Ｌ,可应用于水和废水中微量氰化物的测定。     

Evaluation of media for simultaneous enumeration of total coliform and Escherichia coli in drinking water supplies by membrane filtration techniques

This study evaluated three different dehydrated media for simultaneous detection and enumeration of total coliform （TC） and Escherichia coil in drinking water samples with a standard membrane filtration procedure. The experiment indicated that the differential coliform agar （DCA） medium was the most effective among the tested media in enumerating TC and E. coil, without the need for extensive accompanying confirmation tests. The results for DCA medium were highly reproducible for both TC and E. coil with standard deviation of 6.0 and 6.1, respectively. A high agreement （82%） was found between DCA and m-Endo media on 152 drinking water samples in terms of TC positive. The DCA medium also reduced concealment of background bacteria.     

Effect of spectral resolution on the measurement of monoaromatic hydrocarbons by DOAS

The excellent response characteristics and detection sensitivity with much lower operational cost and the capability to discriminate between the isomer of some monoaromatic hydrocarbons (MAHCs) make di erential optical absorption spectroscopy (DOAS) a powerful tool to trace concentration variation of MAHCs. But due to the similarity in chemical structure, those MAHCs have the similar overlapped characteristic absorption structures, which make the selection of instrumental parameter critical to the accurate detection of MAHCs. Firstly, the spectral resolution used in DOAS system determines the nonlinear absorption of O2 and the mass dependence of characteristic absorption structure; thereby it determines the effect of elimination error of O2 absorption in the atmospheric spectra for the detection of MAHCs. Secondly, spectral resolution determines the di erential absorption characteristics of twelve MAHCs representing major constituents in technical solvents used in the automobile industry and the interference of spectral overlapping. Thirdly, the spectral resolution determines the sensitivity, time resolution and linear range. So the spectral resolution range with the best ratio of signal to noise is used to determine the most suitable spectral resolution range, as well as the spectral resolution range that ensure the characteristic absorption structure of MAHCs and the minimization of O2 absorption interference. Finally, 0.15–0.16 nm (FWHM: full width at half maximum) is assumed to be closest to the optimum spectral resolution and it is confirmed by the results of practical measurement of MAHCs by DOAS.     

基于Ansys APDL的废旧印刷电路板基板破碎分析

为解决废旧印刷电路板资源化中的粗碎问题,利用Ansys APDL模块和CATIA V5三维设计模块,运用以点代线的方法对电路板受力进行了数值模拟;并根据废旧印刷电路板破碎实验,对数值模拟结果进行验证;同时利用实验测得的数据对辊齿进行数值模拟与分析,验证辊齿在破碎过程中的可靠性。结果显示,铜和复合材料在一点的应力均大于其许用应力,判断其发生了断裂;废旧印刷电路板基板在两齿辊差速运行工况下破碎效果最好,证明以点代线方法可靠;辊齿根部的应力小于其许用应力,可靠性良好。为废旧印刷电路板的粗碎方法研究提供参考。其他差速工况(如9~18 r/min)对破碎效果的影响以及齿辊直径对产量的影响仍有待研究。     

An improved grey wolf optimizer algorithm for identification and location of gas emission

Identification of the leakage of hazardous gases plays an important role in the environment protection, human health and safety of industry production. However, lots of current optimization algorithms, such as particle swarm optimization (PSO) and Grey Wolf Optimizer (GWO), suffer from poor global optimization capability and estimation accuracy. In this work, a hybrid differential evolutionary and GWO (DE-GWO) algorithm is proposed. Tested by simulation cases and Prairie Grass emission experimental data, DE-GWO shows higher estimation accuracy than GWO. Compared with the other four optimization algorithms, DE-GWO exhibits finer robust stability under different population sizes, fewer iterations, as well as higher estimation accuracy with fewer search agents. Importantly, simulation results demonstrate that DE-GWO is more suitable to apply in the scene with a small number of sensors. Therefore, the proposed in this paper outperforms other optimization algorithms for the gas emission inverse problem. DE-GWO can provide reliable estimation towards gas emission identification and positioning, which shows huge potential as the data analysis module of real-time monitoring and early warning system.