饮食业油烟道火灾的模糊事件树分析

对饮食业油烟道火灾事故进行事件树分析时,历史数据的缺乏常常导致无法进行事件序列的定量计算.针对这一问题,利用专家对事故的模糊评判,引入模糊事件树进行定量计算研究.在模糊集理论的基础上,结合德尔菲法和判断矩阵法, 将模糊性语言转换为三角模糊数或梯形模糊数,应用模糊数截集以及模糊数清晰化方法,对后果事件发生概率进行计算.研究表明,饮食业油烟道火灾事故概率的模糊事件树分析是切实可行的,有助对饮食业油烟道火灾的认识、预防和扑救工作.     

Waste polyvinylchloride derived pitch as a precursor to develop carbon fibers and activated carbon fibers

Polyvinylchloride (PVC) was successfully recycled through the solvent extraction from waste pipe with an extraction yield of ca. 86%. The extracted PVC was pyrolyzed by a two-stage process (260 and 410 degrees C) to obtain free-chlorine PVC based pitch through an effective removal of chlorine from PVC during the heat-treatment. As-prepared pitch (softening point: 220 degrees C) was spun, stabilized, carbonized into carbon fibers (CFs), and further activated into activated carbon fibers (ACFs) in a flow of CO2. As-prepared CFs show comparable mechanical properties to commercial CFs, whose maximum tensile strength and modulus are 862 MPa and 62 GPa, respectively. The resultant ACFs exhibit a high surface area of 1200 m2/g, narrow pore size distribution and a low oxygen content of 3%. The study provides an effective insight to recycle PVC from waste PVC and develop a carbon precursor for high performance carbon materials such as CFs and ACFs.     

Potential toxicity of amphenicol antibiotic: binding of chloramphenicol to human serum albumin

Antibiotics are widely used in daily life but their abuse has posed a potential threat to human health. To evaluate the toxicity of chloramphenicol (CAP) at the protein level, the interaction between CAP and human serum albumin (HSA) was investigated by fluorescence, Ultraviolet–visible (UV–Vis) absorption, Fourier transform infrared (FT-IR) spectroscopy and molecular docking methods. Fluorescence data revealed that the fluorescence quenching of HSA by CAP was the result of the formation of CAP–HSA complex, and the binding constant was determined to be 3.196?×?10⁴ L mol^?1 at 310 K. The thermodynamic determination indicated that the interaction was driven by enthalpy change and entropy change together, where the multiple hydrogen bonds (CAP and the residues Arg 222 and His 242 of HSA) and van der Waals forces were the dominant binding force. The site marker competition revealed that CAP bound into sub-domain IIA of HSA. The binding of CAP induced the drastic reduction in α-helix conformation and the significant enhancement in β-sheet conformation of HSA. Molecular docking study further confirmed the binding mode obtained by experimental study. This work provides a new quantitative evaluation method for antibiotics to cause the protein damage.     

Fractionation of plutonium in environmental and bio-shielding concrete samples using dynamic sequential extraction

Fractionation of plutonium isotopes (²³⁸Pu, ^239,240Pu) in environmental samples (i.e. soil and sediment) and bio-shielding concrete from decommissioning of nuclear reactor were carried out by dynamic sequential extraction using an on-line sequential injection (SI) system combined with a specially designed extraction column. Plutonium in the fractions from the sequential extraction was separated by ion exchange chromatography and measured using alpha spectrometry. The analytical results show a higher mobility of plutonium in bio-shielding concrete, which means attention should be paid to the treatment and disposal of nuclear waste from decommissioning.     

涪江上游滑坡相关因素研究

采用灰色系统理论的关联度分析方法，研究了涪江上游骨滑坡的主要形成条件及触发因素。结果显示，相对主同差是滑坡的主要形成条件，地震是滑坡的主要触发因素，此外，还对滑坡相关因素进行了相关显著性比较，评价了每项相关因素的其中所起的作用，最后讨论了灰色系统理论的关联度分析方法在滑坡研究中的利弊。     

Isolation and characterization of a strain with high microbial attachment in aerobic granular sludge

Aerobic granule is a special microbial aggregate associated with biofilm structure. The formation of aerobic granular sludge is primarily depending on its bacterial community and relevant microbiological properties. In this experiment, a strain with high microbial attachment was isolated from aerobic granular sludge, and the detailed characteristics were examined. Its high attachment ability could reach 2.34 (OD_600nm), while other low attachment values were only around 0.06-0.32, which indicated a big variation among the different bacteria. The strain exhibited a very special morphology with many fibric fingers under SEM observation. A distinctive behaviour was to form a spherical particle by themselves, which would be very beneficial for the formation and development of granular sludge. The EPS measurement showed that its PN content was higher than low attachment bacteria, and 3D-EEM confirmed that there were some different components. Based on the 16S rRNA analysis, it was identified to mostly belong to Stenotrophomonas. Its augmentation to particle sludge cultivation demonstrated that the strain could significantly promote the formation of aerobic granule. Conclusively, it was strongly suggested that it might be used as a good and potential model strain or chassis organism for the aerobic granular sludge formation and development.     

Assessing economic sustainability and ecological efficiency with genuine progress indicator: a case study of the Yangtze River Delta from 2000 to 2018

To achieve urban sustainability, it is critical to enhance the environment, economy, and society simultaneously. This study adopted the revised genuine progress indicator (GPI) and ecological footprint (EF) to evaluate the ecological efficiency and economic sustainability of the Yangtze River Delta from 2000 to 2018. Spatial analysis was utilized to identify spatial autocorrelation. A total of 27 cities were then partitioned through k-means cluster analysis. The results showed that GPI and ecological efficiency improved rapidly, but economic sustainability showed a downward trend. GPI and GDP had a high degree of spatial correlation, especially in Suzhou-Wuxi-Changzhou Metropolitan Area. However, no spatial correlation existed between GPI and EF. The city with high GEE can reach 3000 $/gha, indicating the city consumed 1 global hectare to create $3000 of genuine economic growth. Shanghai, Hangzhou, and Taizhou were cities with the highest level of economic sustainability and ecological efficiency. The spatiotemporal characteristics of economic sustainability and ecological efficiency revealed in this study will provide theoretical guidance for alleviating ecological pressure and promoting economic sustainable development.

     

微波协同活性炭处理偶氮染料废水的研究

以粉末活性炭为催化剂,采用微波协同活性炭工艺,对偶氮染料(酸性芷青GGR和酸性嫩黄G)废水进行处理。考察了活性炭用量、微波功率、辐射时间、偶氮染料初始浓度对2种偶氮染料去除率的影响。实验结果表明,酸性芷青GGR初始质量浓度为100mg/L、活性炭用量为12.5g/L、微波辐射时间为10min、微波功率为500W条件下,酸性芷青GGR的去除率可达90.28%;酸性嫩黄G初始质量浓度为100mg/L、活性炭用量为10.0g/L、微波辐射时间为8min、微波功率为500W条件下,酸性嫩黄G的去除率可达95.87%;微波协同活性炭处理2种偶氮染料的反应均呈现一级反应动力学特征。     

MnxCe1-xO2／γ-Al2O3催化剂的制备及其催化甲苯的燃烧性能

以γ-Al2O3为载体,以MnxCe1-xO2为催化活性组分,采用浸渍法制备了一系列负载型MnxCe1-xO2／γ-Al2O3催化剂（x=0、0．2、0．4、0．6、0．8、0．9、1）,在固定床反应器中评价了催化剂对甲苯的催化燃烧性能。结果表明,MnxCe1-xO2／γ-Al2O3催化剂的催化活性与催化剂的焙烧温度、活性组分MnxCe1-xO2的负载量以及Mn、Ce摩尔比有显著关系,其中焙烧温度550℃、负载量为20％、Mn、Ce摩尔比为4：1时,即MnxCe1-xO2／γ-Al2O3催化剂对甲苯的催化性能最佳,反应温度为180℃时,甲苯的转化率达到95％。并在连续100h的稳定性操作后,催化剂的活性基本无变化。采用XRD、BET以及SEM等分析测试手段对催化剂的结构以及表面进行了表征。     

Potential particulate pollution derived from UV-induced degradation of odorous dimethyl sulfide

UV-induced degradation of odorous dimethyl sulfide (DMS) was carried out in a static White cell chamber with UV irradiation. The combination of in situ Fourier transform infrared (FT-IR) spectrometer, gas chromatograph-mass spectrometer (GC-MS), wide-range particle spectrometer (WPS) technique, filter sampling and ion chromatographic (IC) analysis was used to monitor the gaseous and potential particulate products. During 240 min of UV irradiation, the degradation e ciency of DMS attained 20.9%, and partially oxidized sulfur-containing gaseous products, such as sulfur dioxide (SO2), carbonyl sulfide (OCS), dimethyl sulfoxide (DMSO), dimethyl sulfone (DMSO2) and dimethyl disulfide (DMDS) were identified by in situ FT-IR and GC-MS analysis, respectively. Accompanying with the oxidation of DMS, suspended particles were directly detected to be formed by WPS techniques. These particles were measured mainly in the size range of accumulation mode, and increased their count median diameter throughout the whole removal process. IC analysis of the filter samples revealed that methanesulfonic acid (MSA), sulfuric acid (H2SO4) and other unidentified chemicals accounted for the major non-refractory compositions of these particles. Based on products analysis and possible intermediates formed, the degradation pathways of DMS were proposed as the combination of the O(1D)- and the OH- initiated oxidation mechanisms. A plausible formation mechanism of the suspended particles was also analyzed. It is concluded that UV-induced degradation of odorous DMS is potentially a source of particulate pollutants in the atmosphere.