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1.
物理化学课程创新教学模式是以学生学习为中心,吐故纳新,优化精选,以新颖或变化的教学方式进行教学。调查表明创新教学模式受到绝大多数学生的肯定和认可,有效地调动学生的积极性,提高了学生对物理化学的学习和探究兴趣,学生提问问题的广度和难度发生显著变化。该教学模式能够逐步提升学生的创新意识和创新能力。 相似文献
2.
Seong-Ku Kim Joon Kyu Lee Yong-Mo Kim Jae-Hyun Ahn 《Journal of Mechanical Science and Technology》2002,16(7):1009-1018
The Representative Interactive Flamelet (RIF) concept has been applied to numerically simulate the combustion processes and
pollutant formation in the direct injection diesel engine. Due to the ability for interactively describing the transient behaviors
of local flame structures with CFD solver, the RIF concept has the capabilities to predict the auto-ignition and subsequent
flame propagation in the diesel engine combustion chamber as well as to effectively account for the detailed mechanisms of
soot formation, NOX formation including thermal NO path, prompt and nitrous NOX formation, and reburning process. Special emphasis is given to the turbulent combustion model which properly accounts for
vaporization effects on the mixture fraction fluctuations and the pdf model. The results of numerical modeling using the RIF
concept are compared with experimental data and with numerical results of the commonly applied procedure which the low-temperature
and high-temperature oxidation processes are represented by the Shell ignition model and the eddy dissipation model, respectively.
Numerical results indicate that the RIF approach including the vaporization effect on turbulent spray combustion process successfully
predicts the ignition delay time and location as well as the pollutant formation. 相似文献
3.
F.A. Rodrigues 《Cement and Concrete Research》2003,33(6):823-827
This paper describes the synthesis of cements, chemically and structurally related to Ca2SiO4. Silica was obtained from rice hull after heating at 600 °C. Calcium oxide and small amounts of barium chloride were mixed in order to obtain a final (Ca/Si) or (Ca+Ba)/Si ratio equal to 1.95, 1.90, and 1.80, which is lower than in the conventional cement. The solids were mixed and ultrasonically treated for 1 h with a water/solid ratio of about 20. After drying and grinding, the mixtures were heated up to 1100 °C. It was possible, in some cases, to obtain a cementitious material. These cements are structurally related to β-Ca2SiO4 and the lower (Ca+Ba)/Si ratio obtained was 1.95. The initial chemical compositions of these cements are: (Ca1.83+Ba0.12)SiO4 and (Ca1.79+Ba0.16)SiO4. A further lowering in the (Ca+Ba)/Si ratio changes the nature of the silicates. 相似文献
4.
The Steady radial distribution of chemical species in a wire‐to‐cylinder ozone generator filled with pure oxygen has been computed by applying four different plasma chemistry models of increasing complexity. The most complete model considers ten species (e, O2 +, O2 ?, O3 ?, O?, O2, O2(1Δg), O2(1∑g +), O and O3) and 79 reactions, including ionization by electron impact, electron attachment and detachment, electron-ion recombination, charge transfer, etc. The chemical model is coupled with the electrical model through Poisson's equation. The spatially averaged ozone density has been computed as a function of the current intensity and compared with the experimental values obtained by UV spectroscopy. 相似文献
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The kinetics of gasification of carbon deposited on nickel foils and nickel-alumina catalysts by steam, carbon dioxide and hydrogen are reported for the temperature range 450–850°C. At atmospheric pressure steam is the most effective gasifying agent. In all cases, the kinetic data obtained at lower temperatures (below 600°C) is consistent with control of the process by the chemical reaction. As the temperature increases, the rates of gasification by steam and carbon dioxide are limited by mass transfer effects. The concentration of methane near reaction sites affects the rate of hydrogen gasification above 650°C. 相似文献
9.
Advanced oxidation processes are defined as those which involve the generation of hydroxyl radicals in sufficient quantity to affect water purification. The theoretical and (practical yield of OH from O3 at high pH, 03/H202, O3/UV and H2O2/UV systems is reviewed. New data is presented which illustrates the importance of direct photolysis in the O3/UV process, the effect of the H202:03 ratio in the O3/H2O2 process, and the impact of the low extinction coefficient of H2O2 in the H202/UV process. 相似文献
10.
The stoichiometric association constants, K, the thermodynamic association constant, KA, and the other thermodynamic parameters such as ΔS°, ΔH° and ΔG° for the association between each of the Ca and Mg ions with benzoate, o-toloate, o-chlorobenzoate and salycylate have been determined at 25°C, 35°C and 45°C in aqueous media. Ion-selective electrode technique has been used in the measurements of Ca and Mg ion activitiesThe trend of association behavior of both Ca and Mg aromatic salts could not be explained on the basis of pKa of the mother organic acids but could be explained based on the trend of Hammet function σ of these salts themselves relative to the corresponding benzoate salt. 相似文献