基于信息融合与GM的石油罐区安全监控预测模型

近年来,石油罐区安全事故发生频率呈不断上升趋势。为有效增强罐区安全监控预警系统监测数据的可靠性,并实现对事故的早期预警,基于多传感器信息融合技术和灰色模型(GM)理论,建立出石油罐区安全监控预测模型。首先,研究了基于递推最小二乘法改进的最优加权融合算法,并将其作为一级(特征级)融合模型,其次,介绍分析了灰色预测理论及GM(1,1)模型的实现过程,最后建立出基于GA-BP神经网络算法的二级(决策级)数据融合模型,并得到石油罐区安全监控预测模型。     

基于GA-ELM的冲击地压危险性预测研究

为提高冲击地压预测的效率和准确率,在分析冲击地压影响因素的基础上,提出了一种将遗传算法(GA)与极限学习机(ELM)相结合的冲击地压预测的新方法。为了避免ELM受输入权值矩阵和隐含层偏差随机性的影响,算法采用GA对ELM的输入权值矩阵和隐含层偏差进行优化,建立GA-ELM冲击地压预测模型。利用某矿冲击地压统计数据对该模型进行了实例分析,将ELM、SVM和BP算法预测结果与该模型进行了对比分析。结果表明:GA-ELM模型具有较高的预测精度,可以相对准确、有效地对冲击地压发生的可能性进行预测。     

基于DEA和Malmquist指数的煤矿安全投入效率评价

为了系统的评价煤矿安全投入效率,采用DEA（数据包络分析）方法,选取我国1991~2010年煤矿安全投入产出数据构建DEA模型,其中煤矿安全投入指标为采煤机械化程度、工程技术人员百分比、颁布煤矿安全法规数和行业标准,产出指标为煤矿百万吨死亡率。根据构建的DEA模型对每年的效率进行分析和评价,并提出建议。同时运用Malmquist指数（全要素生产力指数）对煤矿安全投入效率进行分解研究。研究结果表明,从静态上看,我国仅有1993年和2010年当年的煤矿安全投入和产出都达到了最优状态,并且随着煤矿安全投入逐年增加,煤矿安全投入技术效率、纯技术效率、规模效率逐年提升。从动态上看,我国煤矿安全投入Malmquist指数的提高对技术的依赖很明显,无论是技术进步还是技术效率的提高都会相应的提高Malmquist指数。     

Responses of bacterial strains isolated from drinking water environments to N-acyl-L-homoserine lactones and their analogs during biofilm formation

Often as a result ofbiofilm formation, drinking water distribution systems （DWDS） are regularly faced with the problem of microbial contamination. Quorum sensing （QS） systems play a marked role in the regulation of microbial biofilm formation; thus, inhibition of QS systems may provide a promising approach to biofilm formation control in DWDS. In the present study, 22 bacterial strains were isolated from drinking water-related environments. The following properties of the strains were investigated： bacterial biofilm formation capacity, QS signal molecule N-acyl-L-homoserine lactones （AHLs） production ability, and responses to AHLs and AHL analogs, 3-chloro-4-（dichloromethyl）-5-hydroxy-2（5H）- furanone （MX） and 2（5H）-furanone. Four AHLs were added to developed biofilms at dosages ranging from 0.1 nmol.L J to 100nmol.L1. As a result, the biofilm growth of more than 1/4 of the isolates, which included AHL producers and non-producers, were significantly promoted. Further, the biofilm biomasses were closely associated with respective AHLs concentrations. These results provided evidence to support the idea that AHLs play a definitive role in biofilm formation in many of the studied bacteria. Meanwhile, two AHLs analogs demon- strated unexpectedly minimal negative effects on biofilm formation. This suggested that, in order to find an applicable QS inhibition approach for biofilm control in DWDS, the testing and analysis of more analogs is needed.     

Production of N2O in two biologic nitrogen removal processes: a comparison between conventional and short-cut nitrogen removal processes

The N2O production in two nitrogen removal processes treating domestic wastewater was investigated in laboratory-scale aerobic-anoxic sequencing batch reactors （SBRs）. Results showed that N2O emission happened in the aerobic phase rather than in the anoxic phase. During the aerobic phase, the nitrogen conversion to N2O gas was 27.7% and 36.8% of NH＋-N loss for conventional biologic N-removal process and short-cut biologic N-removal process. The dissolved N2O was reduced to N2 in the anoxic denitrification phase. The N2O production rate increased with the increasing of nitrite concentration and ceased when NH＋-N oxidation was terminated. Higher nitrite accumulation resulted in higher NEO emission in the short-cut nitrogen removal process. Pulse-wise addition of 20 mg NO2 -N. L- 1 gave rise to 3-fold of N2O emission in the conventional N-removal process, while little change happened with 20 mg NOS-N L-1 was added to SBR1.     

MiRNA-451 is a potential biomarker for estrogenicity in mouse uterus

The uterotrophic assay has been commonly used to test environmental estrogens in vivo, however, it is often not sensitive enough sometimes. An alternative way is to evaluate estrogenicity through biomarker genes. MicroRNA （miRNA） is a class of regulatory gene, which has been shown to be a good biomarker for many diseases and toxicological effects in recent years, and some evidences showed that estrogen induced response was partially mediated by miRNAs. In this study, two types of microarrays were used to test the 17[3-estradiol （E2） induced miRNA expression profile at different time points in the immature mouse uterus. Statistical analysis showed the aldehyde slide based array had less variation than the amino slide based array, and 11 dysregulated miRNAs were screened out for significant fold change. Real-time PCR was performed to further confirm that 4 out of 7 selected miRNAs, namely miR-451, miR-155, miR-335- 5p, and miR-365, are E2 regulated miRNAs in the uterus. The function of the predicted targets of these miRNAs is involved in cell grow control, which is consistent with the main E2 function in the uterus. MiR-451 had similar strong responses to E2 in the uterus of both immature and overiectomized mice, and could be a potential biomarker for estrogenicity in the uterus.     

Investigation on sampling artifacts of particle associated PAHs using ozone denuder systems

Polycyclic aromatic hydrocarbons （PAHs） are complex organic compounds which are identified as significant carcinogenic to human health. PAHs （mainly in particle phase） are susceptible to atmospheric oxidant gases, especially ozone, nitrogen oxides （NOx）, hydroxyl radical （OH）, and could be degraded on filters during sampling process, leading to an underestimation of ambient PAH concentrations. The goal of this work was to investigate particle associated PAHs sampling artifacts caused by ozone in summer of Beijing. Comparative sampling systems were operated simultaneously during the whole campaign, one with activated carbon ozone denuder, the other being set as conventional sampling system. Activated carbon denuder was testified to be highly efficient to eliminate ozone from air stream. In general, nine particle-bound PAHs observed from conventional sampler were all lower than those from ozone denuder system. The total PAHs （particle phase） concentration was averagely underestimated by 35.9% in conventional sampling procedure. Benzo[a]pyrene （BaP） had the highest percentage of mass loss. founded to have influences Ambient temperature was on PAHs sampling artifacts. High temperature can increase loss of particle associated PAHs during sampling.     

Identification of pakchoi cultivars with low cadmium accumulation and soil factors that affect their cadmium uptake and translocation

The selection and use of low-Cd-accumulating cultivar （LCAC） has been proposed as one of the promising approaches in minimizing the entry of Cd in the human food chain. This study suggests a screening criterion of LCACs focusing on food safety. Pot culture and plot experiments were conducted to screen out LCACs from 35 pakchoi cultivars and to identify the crucial soil factors that affect Cd accumulation in LCACs. Results of the pot culture experiment showed that shoot Cd concentrations under the three Cd treatments significantly varied across cultivars. Two cultivars, Hualv 2 and Huajun 2, were identified as LCACs because their shoot Cd concentrations were lower than 0.2 mg. kg-1 under low Cd treatment and high Cd exposure did not affect the biomass of their shoots. The plot experiment further confirmed the consistency and genotypic stability of the low-Cd- accumulating traits of the two LCACs under various soil conditions. Results also showed that soil phosphorus availability was the most important soil factor in the Cd accumulation of pakchoi, which related negatively not only to Cd uptake by root but also to Cd translocation from root to shoot. The total Cd accumulation and translocation rates were lower in the LCACs than in the high-Cd cultivar, suggesting that Cd accumulation in different cultivars is associated with the Cd uptake by root as well as translocation from root to shoot. This study proves the feasibility of the application of the LCAC strategy in pakchoi cultivation to cope with Cd contamination in agricultural soils.     

Comparison of growth and lipid accumulation properties of two oleaginous microalgae under different nutrient conditions

This study compared the growth and lipid accumulation properties of two oleaginous microalgae, namely, Scenedesmus sp. LX1 and Chlorella sp. HQ, under different nutrient conditions. Both algal species obtained the highest biomass, lipid content and lipid yield under low-nutrient conditions （mBGll medium）. The biomass, lipid content and lipid yield of Scenedesmus sp. LX1 were 0.42g·L^-1, 22.5% and 93.8mg·L^-1, respectively. These values were relatively higher than those of Chlorella sp. HQ （0.30g·L^-1, 17.1% and 51.3mg·L^-1, respectively）. These algae were then cultivated in an SE medium that contained more nutrients; as a result, the biomass and lipid yield of Scenedesmus sp. LX1 reduced more significantly than those of Chlorella sp. HQ. Opposite results were observed in lipid and triacylglycerols （TAGs） contents. The cell sizes of both algal species under low-nutrient conditions were larger than those under high-nutrient conditions. Chlorella sp. HQ cells did not aggregate, but Scenedesmus sp. LX1 cells flocculated easily, particularly under low-nutrient conditions. In summary, low-nutrient conditions favour the growth and lipid production of both algae, but Scenedesmus sp. LX1 outperforms Chlorella sp. HQ.     

粉煤灰沸石分子筛负载氧化铈催化剂的制备及其催化燃烧二氯甲烷性能

以发电厂粉煤灰为原料,采用碱融水热法合成了HZSM-5分子筛（FHZSM-5）,用浸渍法负载10%（w）CeO₂制备了CeO₂/FHZSM-5催化剂,用于二氯甲烷的催化燃烧。盐酸浓度为2 mol/L及粉煤灰和NaOH的质量比为1∶1.2时制备的FHZSM-5纯度最高,结晶度最好,用其制备的CeO₂/FHZSM-5催化剂（CFH-1）催化燃烧二氯甲烷的活性最佳,T₉₀和T₅₀（转化率为90%和50%时对应的反应温度）分别为348 ℃和304 ℃,低于其他条件下制备的同系列催化剂。低空速和低二氯甲烷入口浓度更有利于催化燃烧反应的进行。在100 h的连续稳定性测试中,所制备的CFH-1催化剂表现出较高的稳定性,二氯甲烷转化率一直保持在75%以上。