信息产业发展对区域产业结构高度化的作用机制

构建了信息产业发展与区域产业结构高度化的指标体系,利用基于OWA算子的灰色关联模型融合方法测算了电子信息产业发展与区域产业结构高度化的关联程度.结果表明,电子信息产业的发展是区域产业结构高度化的重要支撑力.东部地区的信息产业发展与区域产业结构高度化指标体系中的环保资金投入增加量和第三产业增加值的关联度较高.中部、西部地区的信息产业发展与新兴产业产值的关联程度较大.从全国范围来看,信息产业的科技创新转化能力对产业结构高度化的推动作用仍较低.     

基于可靠性视角的交通堵塞模型

本文从可靠性角度研究了交通堵塞模型.首先,通过合理的假设,建立了道路系统的可靠性模型.然后,利用补充变量方法及拉普拉斯变换技术,得到了道路系统的畅通率、稳态堵塞频度和首次堵塞前系统的平均畅通时间等道路系统评价指标.     

Excretion of Hydroxy Derivatives of Polycyclic Aromatic Hydrocarbons of the Masses 178, 202, 228 and 252 in the Urine of Coke and Road Workers

Abstract

Urinary PAH-metabolite excretion by non-exposed volunteers, temporarily living on a PAH-poor and PAH-rich diet, respectively, as well as by occupationally PAH-exposed coke plant workers and road workers has been studied. Significant differences in the amount of the metabolites excreted in the urine were detected; the ratio of various metabolites was also found to be different. The mass excretion per liter of the metabolites from phenanthrene was found to be for the unexposed volunteers about 3.5μg/1, for coke plant workers about 70μg/l and for road workers about 35 μg/l. For the metabolites of chrysene the values were 0.03 μg/1 2.5 μg/l and 0.09μg/l, respectively, and for the total metabolites of benzo(a)pyrene: 0.006μg/l for unexposed persons, 0.37 μg/l for coke plant workers and 0.019 μg/l for road workers.     

Tyre rubber friction on a rough road

One of the most challenging aspects of vehicle dynamics is accurate modelling of the tyre-road interface. Forces between the tyre and road need to be accurately represented in simulation. This is challenging over rough roads since the friction changes along the road due to large surface asperities.The Heinrich/Klüppel friction coefficient estimation model has been implemented on smooth roads in the past. However, this study investigates the applicability of using this model over a rough but hard terrain, such as Belgian paving or cobblestones. The model is based on physical properties that can be determined mathematically or experimentally. The study includes detailed terrain topography and the difference between the top and bottom topography is used to determine the radially averaged PSD. Emphasis is placed on finding and implementing the flash temperature in a practical manner that could also be used in further studies.An experimental setup is built to validate the model. The experimental friction coefficient is compared to the friction coefficient calculated using the Heinrich/Klüppel model. The relative percentage error difference between experimental and friction model results is found to be less than 10% on a smooth concrete road and 20% on a rough road (concrete Belgian paving).     

Temperature and Inoculum Origin Influence the Performance of Ex-Situ Biological Hydrogen Methanation

The conversion of H₂ into methane can be carried out by microorganisms in a process so-called biomethanation. In ex-situ biomethanation H₂ and CO₂ gas are exogenous to the system. One of the main limitations of the biomethanation process is the low gas-liquid transfer rate and solubility of H₂ which are strongly influenced by the temperature. Hydrogenotrophic methanogens that are responsible for the biomethanation reaction are also very sensitive to temperature variations. The aim of this work was to evaluate the impact of temperature on batch biomethanation process in mixed culture. The performances of mesophilic and thermophilic inocula were assessed at 4 temperatures (24, 35, 55 and 65 °C). A negative impact of the low temperature (24 °C) was observed on microbial kinetics. Although methane production rate was higher at 55 and 65 °C (respectively 290 ± 55 and 309 ± 109 mL CH₄/L.day for the mesophilic inoculum) than at 24 and 35 °C (respectively 156 ± 41 and 253 ± 51 mL CH₄/L.day), the instability of the system substantially increased, likely because of a strong dominance of only Methanothermobacter species. Considering the maximal methane production rates and their stability all along the experiments, an optimal temperature range of 35 °C or 55 °C is recommended to operate ex-situ biomethanation process.     

Impedance-effects in capacity estimation

Formulas for the capacity of an unsignalized intersection for traffic streams which are subordinated to two or more streams of higher priority are developed. The case of only two conflicting streams analysed by Tanner (1962) is extended. The process at the intersection is modelled as a priority queuing system with Poisson input and service times depending on the work load.     

煤焦油及其组分在超临界水中的反应特性研究

采用间歇超临界水（supercritical water, SCW）反应器,考察了三种煤焦油及其组分在SCW中的反应性。实验结果表明,沥青质裂解活性高的煤焦油在SCW中反应,轻质产物多,轻质化效果好。沥青质是轻质化反应的主要组分,它发生两极分化反应生成轻油和残焦。与常压N2热解相比,SCW可以促进沥青质转化为轻油并抑制缩合成焦的反应。由沥青质组分反应产物推断,煤焦油沥青质的芳香核主要是由1~4环的芳香族化合物构成。轻油组分在SCW中较为稳定,不足10%的轻油转化为沥青质和残焦。残焦组分在SCW中不发生反应。基于各组分的反应,探讨了煤焦油组分在SCW中的反应路径。     

菱沸石-粘土复合物在沥青精制中的应用

阿尔伯塔的油砂资源日益成为北美重要的战略性能源供给.本实验室通过采用碱性条件下在高岭土表面上组装菱沸石的方法,合成了新型的菱沸石-粘土复合材料,并证明此复合材料是比菱沸石更好的油砂沥青精制剂.XRD,SEM,TEM,N2物理吸附和XPS表面元素分析结果表明,菱沸石-粘土复合材料具有大体积烃类分子可及的独特的外表面,该复合材料不仅可降低油砂沥青的裂解反应温度,同时还可大幅度脱除沥青中的硫、氮、镍和钒等杂质.     

Upgrading low-quality natural gas with H2S- and CO2-selective polymer membranes: Part II. Process design, economics, and sensitivity study of membrane stages with recycle streams

The cost of membrane separation processes for removing CO₂ and H₂S from low-quality natural gas can be reduced for some concentration ranges of CO₂ and H₂S by utilizing concurrently two different types of polymer membranes, one with a high CO₂/CH₄ selectivity and the other with a high H₂S/CH₄ selectivity. The polymers considered in this exploratory study were 6FDA-HAB polyimide for the removal of CO₂ and [poly(ether urethane urea)] (PEUU) for the removal of H₂S. It was required that the concentrations of CO₂ and H₂S in low-quality natural gas be reduced to US pipeline specifications (≤2 mol% CO₂ and ≤4 ppm H₂S). Low-quality natural gas was simulated in this study by CH₄/CO₂/H₂S mixtures containing up to 40 mol% CO₂ and 10 mol% H₂S. Twenty-seven membrane process configurations (PCs) were examined by computer simulations and optimized in order to determine the most economical configurations. Part I of this study considered only PCs without recycle streams [J. Hao, P.A. Rice, S.A. Stern, Upgrading low-quality natural gas with H₂S- and CO₂-selective polymer membranes. Part I. Process design and economics of membrane stages without recycle streams, J. Membr. Sci. 209 (2002) 177–206]. In Part II, reported below, the study was extended to two- and three-stage PCs with various recycle options. A sensitivity analysis was also made to determine the effects of variations in feed flow rate, feed pressure, membrane module cost, and wellhead price of natural gas on process economics. The economically optimal PCs were found to be either two membrane stages connected in series with or without recycle streams or single stages without recycle, depending on feed composition and selected operating conditions. The optimal two-stage PCs with recycle streams would utilize the H₂S/CH₄-selective membranes in the first stage and either the CO₂/CH₄ or the H₂S/CH₄-selective membranes, or both, in the second stage. Three-stage membrane PCs were not found to be economically competitive under the conditions assumed in this study.