HAZOP分析技术在聚丙烯装置的应用

运用HAZOP技术系统识别了聚丙烯装置存在的工艺危险和可操作性问题,提出了相关改进建议措施;并对HAZOP技术应用过程中经常遇到的典型问题,包括后果如何确定、原因能否用偏差代替、如何确定现有保护措施、如何评估风险度等,进行了探讨。     

Mobility and sulfidization of heavy metals in sediments of a shallow eutrophic lake, Lake Taihu, China

The technique of DGT (diffusive gradients in thin films) using three diffusive gel thicknesses was applied to estimate the mobility and bioavailability of heavy metals in sediments and porewater of Lake Taihu, China. The DGT results showed significantly positive correlations between Co, Pb, Cd and Mn, and Ni and Fe concentrations in porewater. Cu and Zn showed a significantly negative correlation with Mn, due to Cu combination with carbonates and Zn derived from agricultural pollution, respectively. The rank order of average concentrations of Co, Ni and Cd at each station was DGT_1.92 > DGT_0.78 > DGT_0.39, suggesting stronger resupply from sediments to porewater when using thicker diffusive gels. Comparing centrifugation and DGT measurements, Co, Ni and Cd are highly labile; Mn and Fe are moderately labile; and Cu, Zn and Pb are slightly labile. The variations of AVS concentrations in sediment cores indicate that metal sulfides in deeper layers are easily diffused into surface sediments.     

美国新潮:通过明星的嘴和脸来环保

在纽约,人们不得不尝试采取各种形式来推进环境保护工作的进程,八仙过海各显其能.去年7月4日华盛顿庆祝国庆节的游行中,我就亲眼看到一个宣传环保的队伍,队中的每个人都拿着一个垃圾袋,边走边收集游行者和观众丢弃的易拉罐,成为国庆节游行的一个亮点.     

Soil enzyme activities and their indication for fertility of urban forest soil

To reveal the biological characteristics of urban forest soil and the effects of soil enzyme on soil fertility as well as the correlation between physicochemical properties and enzyme activities, 44 urban forest soil profiles in Nanjing were investigated. Basic soil physicochemical properties and enzyme activities were analyzed in the laboratory. Hydrogen peroxidase, dehydrogenase, alkaline phosphatase, and cellulase were determined by potassium permanganate titration, TTC (C₁₉H₁₅N₄·Cl) colorimetry, phenyl phosphate dinatrium colorimetry, and anthrone colorimetry, respectively. The result showed that soil pH, organic carbon (C), and total nitrogen (N) had great effects on hydrogen peroxidase, dehydrogenase, and alkaline phosphatase activities in 0–20 cm thick soil. However, pH only had great effect on hydrogen peroxidase, dehydrogenase, and alkaline phosphatase activities in 20–40 cm thick soil. Hydrogen peroxidase, dehydrogenase, and alkaline phosphatase were important biological indicators for the fertility of urban forest soil. Both in 0–20 cmand 20–40 cmsoil, soil enzyme system (hydrogen peroxidase, dehydrogenase, alkaline phosphatase, and cellulase) had a close relationship with a combination of physicochemical indicators (pH, organic C, total N, available K, available P, cation exchange capacity (CEC), and microbial biomass carbon (C_mic)). The more soil enzyme activities there were, the higher the fertility of urban forest soil.     

使用多边形中空铝坯料冷挤压生产多边形铝螺母的工艺方法

介绍了一种已申请国家专利的铝螺母的加工方法。并就冷挤压时零件的变形、模具机构的设计等作了较为详细的论述。     

基于FTA-SVM的车辆发动机故障识别方法

发动机结构日益复杂,其故障具有多样性和频发性的特点,收集大量故障样本存在很多实施障碍。为了提高车辆发动机的故障识别的效率和准确性,提出了一种新的结合故障树(FTA)和支持向量机(SVM)各自特点,从故障模式分析到故障类型识别的FTA-SVM故障识别方法。首先利用故障树在复杂系统故障模式分析中的优势,找出系统的故障模式,建立故障树模型,通过对故障树模型中各故障事件的分析,采集与故障事件状态相关的数据,建立数据与故障树底事件的映射模型,最后利用支持向量机在小样本数据处理中的优势,进行故障类型的识别。以发动机的失火故障为例建立了发动机失火故障树模型及故障数据与故障模式映射模型,验证了FTA-SVM方法的有效性和适用性。