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81.
82.
市政府道路是城市道路的主要组成部分。通过对市政府道路养护的必要性、养护机械配置的问题以及如何构建合理的评价指标体系等进行阐释,为市政府道路养护工作提供相应的参考意见。 相似文献
83.
Fred J. Parker 《Journal of the American Ceramic Society》1990,73(4):929-932
The characterization and properties of ceramic composites containing the phases Al2 TiO5 , ZrTiO4 , and ZrO2 are described. The range of compositions investigated gives very low average thermal expansions (α24–1000°C as low as −2.0 × 10−6 °C−1 ) and excellent high-temperature stability. The low thermal expansions are apparently due to a combination of microcracking by the titanate phases and a contractive phase transformation by the ZrO2 . The crystal chemistry and microstructure of the product are processing dependent. Although the composites represent a complex microcracking system, the low thermal expansions and high-temperature stability make them potential candidates for commercial applications requiring thermal shock resistance. 相似文献
84.
研究了三相鼓泡床中的临界固含率,以空气作气相,水、乙醇-水、丙酮-水、萜松醇-二甲苯作液相,石英砂、煤、雷奈镍作为固相。分析了鼓泡柱的高径比、气体速度、固体粒子的大小和比重、液体的粘度对临界固含率的影响,提出了含有这些参数的无因次数群的关联式,讨论了本文提出的关联式和文献报导的差别。 相似文献
85.
Daizo Kunii 《Chemical engineering science》1980,35(9):1887-1911
A general procedure is proposed for innovative research and development of gas-solid reactor systems, with a brief explanation of the significance of each step in the procedureBased upon the contacting mode between gas and solid phases, as well as the ways of supplying thermal energy to the reacting regions, various types of gas-solid reactor systems are classified by using tables of so called “matrix” form, for thermal cracking and gasification of heavy oils, gasification of coal, gasification of solid waste, calcination of limestone, clinkering of cement and reduction of iron ore.The importance of fundamental concepts is emphasized for successful research and development by presenting several examples; namely, calcination of limestone, thermal cracking of heavy oils and gasification of solid waste materials.In connection with the direction in which fundamental research should be oriented, four primary ways of thinking are proposed, which can be applied to obtain innovative ideas for further research and development in this field.One example of the author's practical experience was selected to show the role of the fundamental research in the course of large scale development. Finally the author outlines the role of chemical reaction engineering to innovate the novel gas-solid reactor systems which may be inevitable for simultaneous solution of the three big E's; namely, Energy, Environment and Economy. 相似文献
86.
电解法处理利福霉素SV钠废渣分离液的研究 总被引:2,自引:0,他引:2
根据电化学原理,采用电解法,利用铁屑与炭粒作电极,处理利福霉素SV钠药渣分离液,讨论各种因素对分离液污染物作效果的影响,COD去除率可达91.8%左右,脱色率可达95%左右。 相似文献
87.
We state and analyse one-shot methods in function space for the optimal control of nonlinear partial differential equations (PDEs) that can be formulated in terms of a fixed-point operator. A general convergence theorem is proved by generalizing the previously obtained results in finite dimensions. As application examples we consider two nonlinear elliptic model problems: the stationary solid fuel ignition model and the stationary viscous Burgers equation. For these problems we present a more detailed convergence analysis of the method. The resulting algorithms are computationally implemented in combination with an adaptive mesh refinement strategy, which leads to an improvement in the performance of the one-shot approach. 相似文献
88.
89.
The axial dispersion-sedimentation model is commonly used to describe the axial concentrations of solids in three phase bubble columns at low liquid velocities. When the two parameters of this model, the particle settling velocity and the solids axial dispersion coefficient, are uncoupled by the use of various assumptions, physically unrealistic values of these parameters often result. Direct experimental measurements of solids settling rates in bubbly gas-liquid mixtures were carried out. The measured mean settling velocities decreased slightly with gas flow rate and were equal to or slightly less than the single particle free settling velocity in the liquid alone. Solids axial dispersion coefficients were also obtained from the solids settling rate distribution data, and gave values considerably less than the experimental liquid axial dispersion coefficient. 相似文献
90.