强震前淮北台地倾斜短临异常的探讨

地倾斜观测是目前我国作为探索地震前兆的重要手段之一,实践证明地倾斜与地震存在着一定的对应关系.本文尝试利用淮北台FSQ型及JB型倾斜仪的观测结果,通过分析,获取与全球、全国强震有关的短临前兆信息以及总结其基本特征,得到了一些经验性认识.     

高压变频调速装置在转炉烟气净化及煤气回收系统的应用及发展前景

在此介绍了昆明钢铁公司第二炼钢厂3×30t转炉烟气净化及煤气回收系统上采用的高压变频调速装置的技术参数和设计方案,对各类调速装置的选型进行了分析对比,对应用效果和使用经济性进行了分析,并介绍了高压变频调速装置在转炉炼钢厂的应用前景.     

金属喷涂层在青海盐湖水中的腐蚀初探

喷锌、喷铝、喷锌铝合金三种保护层材料在青海格尔木盐水湖进行1年暴露试验,采用电化学方法研究了该金属喷涂层材料的腐蚀情况,并将其与碳钢的实验结果相对照,初步探讨了其耐蚀机理。     

Role of interfacial electron transfer reactions on sulfamethoxazole degradation by reduced nontronite activating H2O2

It has been documented that organic contaminants can be degraded by hydroxyl radicals ( • OH) produced by the activation of H₂ O₂ by Fe(II)-bearing clay. However, the interfacial electron transfer reactions between structural Fe(II) and H 2 O 2 for • OH generation and its effects on contaminant remediation are unclear. In this study, we first investigated the relation between • OH generation sites and sulfamethoxazole (SMX) degradation by activating H₂O₂ using nontronite with different reduction extents. SMX (5.2–16.9 μmol/L) degradation first increased and then decreased with an increase in the reduction extent of nontronite from 22% to 62%, while the • OH production increased continually. Passivization treatment of edge sites and structural variation results revealed that interfacial electron transfer reactions between Fe(II) and H 2 O 2 occur at both the edge and basal plane. The enhancement on basal plane interfacial electron transfer reactions in a high reduction extent rNAu-2 leads to the enhancement on utilization efficiencies of structural Fe(II) and H 2 O 2 for • OH generation.However, the • OH produced at the basal planes is less efficient in oxidizing SMX than that of at edge sites. Oxidation of SMX could be sustainable in the H 2 O 2 /rNAu-2 system through chemically reduction. The results of this study show the importance role of • OH generation sites on antibiotic degradation and provide guidance and potential strategies for antibiotic degradation by Fe(II)-bearing clay minerals in H 2 O 2 -based treatments.     

菲律宾蛤仔(Ruditapes philippinarum)血淋巴中抑菌活性物质的活性影响因素

为了建立蛤仔血淋巴中抑菌活性物质的快速高效分离、纯化方法，利用正交设计法对影响菲律宾蛤仔血淋巴中抑菌物质抑菌活性的3个因素进行了探讨．结果表明，在本实验条件下，pH对抑菌活性影响最大，温度次之，处理时间的影响最小；而以在pH值为4，温度小于65℃的介质中活性物质能保持较高抑菌活性．提示菲律宾蛤仔血淋巴中抑菌活性物质对热有一定的耐受性，且适于偏酸性的环境．表2参10     

利用广谱性和特异性组合诱变技术选育辅酶Q10高产菌

为提高辅酶Q10产量，采用了对细胞进行全面的非特异性诱变和针对特定途径的特异性诱变相结合的育种策略，以放射型根瘤菌(Rhizobium radiobacter)WSH2601为出发菌株，选择UV射线和亚硝基胍作为诱变剂，在筛选获得放线菌素D抗性突变株的基础上，通过进一步的诱变处理，分别获得了放线菌素D和L-乙基硫氨酸双抗性突变株、放线菌素D和维生素K双抗性突变株，以及抗放线菌素D和X-gal利用能力提高的突变株．与出发菌株相比，突变株辅酶Q10的产量提高幅度达25％-37％，其中一株放线菌素D和L-乙基硫氨酸双抗性突变株WSH-E25，胞内辅酶Q10含量和辅酶Q10总产量分别达到2．86mg g DCW^-1和40．0mg L^-1，均比出发菌株提高了37％，且遗传稳定性良好，图6表2参8     

Probabilistic risk assessment for pedestrian–vehicle collision considering uncertainties of pedestrian mobility

Objectives: The uncertainties of pedestrian mobility are important factors affecting the accuracy and robustness of an active pedestrian protection system. This study is to provide the means for probabilistic risk evaluation of pedestrian–vehicle collision by counting the uncertainties in pedestrian motion.

Method: The pedestrian is modeled by a first-order Markov model to characterize the stochastic properties in mobility according to field experiments of pedestrians crossing an uncontrolled road. Based on the assumption of Gaussian distribution, unscented transformation (UT) is employed to predict the collision risk probability with the symmetric σ-set constructed on the basis of discrete trajectory simulation. Simulation experiments were carried out with 10,000 Monte Carlo (MC) simulations as the reference.

Results: The probability density distributions of time-to-collision, minimal distance, and collision probability estimated by UT coincide with the reference ones under various vehicle–pedestrian conflict scenarios, and the maximal deviation of collision probability from the reference is 5.33%. The UT method is about 600 times faster than the MC method (10,000 runs), which means that the proposed method has the potential for online application.

Conclusions: This article presents an effective and efficient algorithm to estimate the collision probability by using a UT method to solve the nonlinear transformation of uncertainties in pedestrian motion. Simulation results show that the UT-based method achieves accurate collision probability estimation and higher computation efficiency than MC and provides more valuable information concerning collision avoidance than the deterministic methods in the design of a pedestrian collision avoidance system.     

Emissions of intermediate volatility organic compound from waste cooking oil biodiesel and marine gas oil on a ship auxiliary engine

Ship auxiliary engines contribute large amounts of air pollutants when at berth.Biodiesel,including that from waste cooking oil(WCO),can favor a reduction in the emission of primary pollutant when used with internal combustion engines.This study investigated the emissions of gaseous intermediate-volatile organic compounds(IVOCs) between WCO biodiesel and marine gas oil(MGO) to further understand the differences in secondary organic aerosol(SOA) production of exhausts.Results revealed that WCO exhaust exhibited similar IVOC composition and volatility distribution to MGO exhaust,despite the differences between fuel contents.While WCO biodiesel could reduce IVOC emissions by 50% as compared to MGO,and thus reduced the SOA production from IVOCs.The compositions and volatility distributions of exhaust IVOCs varied to those of their fuels,implying that fuel-component-based SOA predicting model should be used with more cautions when assessing SOA production of WCO and MGO exhausts.WCO biodiesel is a cleaner fuel comparing to conventional MGO on ship auxiliary engines with regard to the reductions in gaseous IVOC emissions and corresponding SOA productions.Although the tests were conducted on test bench,the results could be considered as representative due to the widely applications of the test engine and MGO fuel on real-world ships.     

Exposure to polycyclic aromatic hydrocarbons and risk for premature ovarian failure and reproductive hormones imbalance

Polycyclic aromatic hydrocarbons (PAHs) are a typical class of persistent organic pollutants that is ubiquitous worldwide. Previous animal studies suggested that PAHs had adverse effects on female reproduction. However, the human data regarding relationship of PAHs exposure with women reproductive health, such as ovarian dysfunction, are scarce. In this case-control study, the associations of serum levels of PAHs with the risk of premature ovarian failure (POF) and reproductive hormones in Chinese women were investigated, with recruiting 157 POF patients and 217 healthy women. The serum levels of 12 types of PAHs, as well as reproductive hormones, including follicle-stimulating hormone, luteinizing hormone and anti-mullerian hormone, were determined. In the logistic regression models, most individual PAH congeners showed significantly positive correlations with the risk of POF (p < 0.05), except for fluorine and pyrene. Benzo(a)pyrene (BaP), as the most carcinogenic PAH congener, was observed to be significantly positively associated with the risk of POF. After adjustment for age, body mass index, educational levels and household income, per one-unit increase in the log-transformed BaP concentration was significantly correlated with 2.191-fold increased risk of POF (OR = 2.191, 95%CI: 1.634–2.938, p < 0.05). To the best of our knowledge, this is the first study to report an association between internal exposure levels of PAHs and the increased risk of POF in women.     

Spatiotemporal characterization and regional contributions of O3 and NO2: An investigation of two years of monitoring data in Henan, China

To investigate the characteristics of ground level ozone(O_3) for Henan Province,the ambient air quality monitoring data of 2015 and 2016 were analyzed.The result showed that the 8 h-max-O_3 concentrations displayed a distinct seasonality,where the maximum and minimum values,averaging 140.41,54.19 μg/m~3,occurred in summer and winter,respectively.There is a significant correlation between meteorological factors and O_3 concentration.The Voronoi neighborhood averaging analysis indic ated that O_3,temperature,and ultraviolet radiation in Henan province were decreased from northwest to southeast,while relative humidity and precipitation displayed the opposite trend.Besides meteorological factors,the chemical processes play an essential role in ozone formation.Reactions of NO,NO_2 and O_3 form a closed system,and the partitioning point of the OX-component(O_3+NO_2) was at 40 and 80 μg/m~3 for nitrogen oxide(NO_x) in winter and summer,respectively,with NO_2 dominating at higher NO_x pollution and O_3 being the m ajor component at lower levels.The relationship between oxidant(OX=O_3+NO_2)and NOx concentrations were evaluated to understand the regional and local contribution of OX.It showed that high regional contribution occurred in the spring,whereas the highest local contribution lead to the summer peak of O_3 observed in Zhengzhou.This present study reveals important environment impacts from the photochemical process and the meteorological conditions in the region with better understanding on the O_3 characterization.