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Numerical Modeling of NO Formation during Packed-bed Combustion of Coke Granules

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 261-268页

作者： Chunbao Xu, Shengli Wu, Daqiang Cang (Metallurgy school, university of science and {3. Beijing, Beijing 100083. China Institute for chemical Reaction science, Tohoku university, japan) Metallurgy school University of Science and Technology Beijing Beijing 100083 China Institute for chemical Reaction science Tohoku University Japan

A comprehensive kinetic model of NO formation during coke combustion in packed-bed in presence of noncombustible particles was developed. The detailed homogeneous gas-phase chemistry (including 102 chemical reactions), heterogeneous gas-solid chemistry (including 11 reactions) of coke combustion and NO formation, and the heat and mass transfer were taken into account in the present model. The governing equations which are strongly coupled, non-linear and unsteady with 26 unknowns in total, were dispersed into differential equations with the finite differential method. Meanwhile, all the differential equations were numerically solved to give the time-histories and space-distributions oftemperatures of the bed and gas phase as well as the concentrations of all the gaseous species. By comparison, the experimental data were explained well by the calculated results. Based on the kinetic and mathematical model, the effects of O2 content of inlet gas, the initial chemical analysis of coke, bed-temperature and local reductive atmosphere (CO/O2) on NO formation during packed-bed coke combustion were numerically discussed. It was found that coke samples with a higher initial content of [N] and volatile matters, combusted under a suitable O2-containing atmosphere produced less NO emission. The reactions between CO and NO, catalyzed by high temperature surface of coke particles may be responsible for efficient reduction of NO.

关键词： kinetic model NO formation combustion packed-bed coke Metallurgy

Possibility of Reducing Formations of NO_x and SO_2 Simultaneously during Coal Combustion

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International Journal of Minerals,Metallurgy and Materials 2000年第3期14卷 165-169页

作者： Chunbao Xu, Shengli Wu, Daqiang Cang ( Metallurgy school, university of science and {3. Beijing, Beijing 100083. China Institute for chemical Reaction science, Tohoku university, japan) Metallurgy school University of Science and Technology Beijing Beijing 100083 China Institute for chemical Reaction science Tohoku University Japan

Comparing with other NO_x and SO_2 control technologies, in-bed reducing NO_x and SO_2 simultaneously during coal combustion may lower the investment and operation cost. However, there are several possible contradictions between the reduction of NO_x and the capture of SO2 during combustion: 1) CO rich atmosphere is favorable for the reduction of NO_x, whereas O_2 rich favorable for the capture of SO_2; 2) higher preheating temperature of coal is favorable for reducing NO_x, but unfavorable for reducing SO_2; 3. sulphation of some minerals may deactivate their catalytic effect on the reduction of NO_x. The attempts to eliminate such contradictions by coating coal granules with thin layer of monometallic oxides and mixed oxides were proposed. Ni_2O_3.and Fe_2O_3.showed high activity on NOx reduction and CaO and Cr_2O_3.showed good effect on sulfur capture. The mixed metallic oxides, e.g., Fe_2O_3.iO, etc., showed effective for both NO_x reduction and SO_2 retention. It is possible to in-bed reduce NO_x and SO_2 simultaneously if the adhering materials are properly chosen to be difunctional materials of both active catalysts for NO_x reduction reactions and better sorbents for SO_2 retention.

关键词： coal combustion purification of NO and SO catalyst sorbent

Influence of steric and intramolecular inductive effects on the variable trends in R-X (R=Alkyl) bond dissociation energy

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science China Chemistry 2009年第7期52卷 943-951页

作者： CAO ChenZhong school of Chemistry and chemical Engineering, Hunan university of {3. and technology, Xiangtan 411201, China school of Chemistry and chemical Engineering Hunan University of Science and Technology Xiangtan China

The question "why are the variation trends of R-X bond dissociation energy different?" is answered. The R-X bond dissociation energy (BDE) may be influenced by three main factors: the C-X intrinsic bond energy, the 1,3.geminal repulsion, and the intramolecular charge-induced dipole. In the presence of atom X, the variation trend of BDE in R-X (R= Me, Et, i-Pr, t-Bu) is dominated by two factors, the 1,3.geminal repulsion and the intramolecular charge-induced dipole. The former decreases the R-X BDE, and the latter either increases or decreases the R-X BDE. For the series of R-X with the R-C bond (such as R-Me, R-CH == CH2, R-C≡CH, and R-CN), the 1,3.geminal repulsion decreases the R-X BDE, and the variation trends of R-C BDE decrease from Me to t-Bu. As regards the series of R-X (such as R-H, R-BH2, and R-SiH2) in which the electronegativity of atom X is smaller than that of the carbon atom, the above two factors decrease the R-X BDE, and the variation trends of the R-X BDE decrease from Me to t-Bu. As to the series of R-X (such as R-F, R-OH, R-Cl, R-Br, R-I, and R-NH2) in which the electronegativity of atom X is larger than that of the carbon atom, the 1,3.geminal repulsion decreases the R-X BDE, while the intramolecular charge-induced dipole increases the R-X BDE. In this case, the variation trends of R-X BDE depend on the competition of the two factors. As a result, some of them (e. g., R-F, R-OH) increase from Me to t-Bu, some (e. g., R-I) decrease from Me to t-Bu, and some (e. g., R-Br) change very little.

关键词： bond dissociation energy charge-induced dipole geminal repulsion ionic configuration

Mining and Integrating Reliable Decision Rules for Imbalanced Cancer Gene Expression Data Sets

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Tsinghua science and technology 2012年第6期17卷 666-673页

作者： Hualong Yu 1 , Jun Ni 2 , Yuanyuan Dan 3., Sen Xu 4 1. school of Computer science and Engineering, Jiangsu university of science and technology, Zhenjiang 212003. China 2. department of Radiology, Carver College of Medicine, The university of Iowa, Iowa City, IA 52242, USA 3. school of Biology and chemical Engineering, Jiangsu university of science and technology, Zhenjiang 212003. China 4. school of Information Engineering, Yancheng Institute of technology, Yancheng 224051, China school of Computer science and Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China department of Radiology Carver College of Medicine The University of Iowa Iowa City IA 52242 USA school of Biology and chemical Engineering Jiangsu University of Science and Technology Zhenjiang 212003 China school of Information Engineering Yancheng Institute of Technology Yancheng 224051 China

There have been many skewed cancer gene expression datasets in the post-genomic era. Extraction of differential expression genes or construction of decision rules using these skewed datasets by traditional algorithms will seriously underestimate the performance of the minority class, leading to inaccurate diagnosis in clinical trails. This paper presents a skewed gene selection algorithm that introduces a weighted metric into the gene selection procedure. The extracted genes are paired as decision rules to distinguish both classes, with these decision rules then integrated into an ensemble learning framework by majority voting to recognize test examples; thus avoiding tedious data normalization and classifier construction. The mining and integrating of a few reliable decision rules gave higher or at least comparable classification performance than many traditional class imbalance learning algorithms on four benchmark imbalanced cancer gene expression datasets.

关键词： cancer gene expression data class imbalance paired differential expression genes decision ruleensemble learning majority voting

Production of High Carbon Ferrochromium Using Melt Circulation

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International Journal of Minerals,Metallurgy and Materials 1998年第4期12卷 192-202页

作者： Yulong Ding A J Merchant( department of chemical Engineering and chemical {3., Impenal College of science, {3. and Medicine, Prince Consort RoadLondon SW7 2BY, UK)( school of chemical Engineering of the university of Birmingham, Edgbaston, department of chemical Engineering and chemical {3. Imperial College of Science Technology and Medicine Prince Consort Road London SW7 2BY United Kingdom school of chemical Engineering University of Birmingham Edgbaston Birmingham B15 2TT United Kingdom

Some fundamental studies related to the production of high carbon ferrochromium were summarizedusing melt circulation technology carried out in the school of chemical Engineering at the {3. of Birmingham. These studies focused on the kinetics of chromite reduction in Fe-C(-Cr-Si) melts. The effects of feed mode,fluxes, amount and particle size of reductant, particle size of chromite, melt composition and the reduction temperature were investigated. The reduction mechanisms were discussed. The results showed that (1 ) the reduction rates ofsintered chromite Pellets and non-compacted chromite powder in Fe-C(-Cr-Si) melts was generally very low,(2) addition of carbon in the non-compacted chromite feed greatly improved the reduction kinetics, (3. compaction of thecarbon-chromite mixtures into composite Pellets further improved the reduction kinetics and (4) addition of lime inthe composite Pellets increased the reduction rate, while the addition of silica may suppress the posihve effect oflime. It can be concluded that solid-state reduction, smelting reduction and dissolution proceed simultaneouslyduring the reduction of compacted compostite pellets or non-compacted composite mixtures in Fe-C(-Cr-Si) melts,and the early stage of reduction is very likely to be controlled by either or both solid-state and/or gas diffusionthrough the oxide phases and/or the product layers.

关键词： smelting reduction chromite reduction mechanisms ferrochromiumNomenclatures

Estimating fisheye camera parameters from homography

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science China(Information sciences) 2012年第9期55卷 2119-2127页

作者： ZHU HaiJiang 1,YANG Ping 2 & LI ShiGang 3.1 school of Information science and technology,Beijing {3. of chemical technology,Beijing,100029,China 2 National Institute of Metrology,100013.Beijing,China 3.department of Electrical and Electronic Engineering,Tottori {3.,680-8552,Koyama,Tottori,japan school of Information science and technology Beijing University of Chemical Technology Beijing China National Institute of Metrology Beijing China department of Electrical and Electronic Engineering Tottori University Koyama Tottori Japan

This paper presents a method to linearly estimate fisheye camera model parameters from the homography induced by the space plane between two fisheye *** homography is firstly calculated by using four feature points,instead of three points on the same line,in the fisheye *** the constraint on the model parameters of fisheye camera can be derived from the homography under the assumption that fisheye camera model is a polynomial *** the model parameters for different order polynomials are *** proposed technique requires only multiple fisheye images to include a planar scene and need not a priori knowledge of 3. coordinate of the planar *** results with synthetic data and real fisheye images demonstrate the validity of our *** method can also be extended to fisheye image of other planar scene excluding the planar calibration object.

关键词： homography parameter estimation fisheye camera

Mathematic Expression of Kinetic Compensation Effect and Relationship between the Exothermic Decomposition Temperature and Critical Temperature of Thermal Explosion of Eighty-six Energetic Materials

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含能材料 2001年第1期9卷 8-9页

作者： HU Rong zu 1, YANG De suo 2, ZHANG Jiao qiang 3. (1. department of Chemistry,Northwest university, Xi′an 710065, China 2. department of Chemistry and {3. Engineering, Baoji College of Arts and science, Baoji 721007, China 3. department of 西北大学陕西西安 710065 宝鸡文理学院陕西 721007 西北工业大学陕西西安 710072

Two relationships are established using the least squares method,between the kinetic parameters (the apparent activation energy and pre exponential constant),and the exothermic decomposition temperature and ther... 详细信息

关键词： critical temperature of thermal explosion decomposition temperature DSC energetic materials.

ON VECTOR-VALUED FUNCTION SPACES WITH HELLY'S PROPERTY

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Analysis in Theory and Applications 2001年第2期17卷 86-100页

作者： Kazuaki Kitahara (school of science, kwansei {3. university, japan) Toshinao Okada ( Kagawa university, japan) school of science Kwansei-Gakuin University Japan Kagawa university Japan

If a vector valued function space with a Hausdorff locally convex topology has a property such that every closed strongly bounded subset is compact, then we name this property Helly's property. In this paper, we show a class of vector valued function spaces with Helly's property and consider convergence of vector measures and best approximations in function spaces in this class.

关键词： Math ON VECTOR-VALUED FUNCTION SPACES WITH HELLY’S PROPERTY

Study on the Miscibility and Phase Behavior of Polyoxymethylene with Novolak

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Journal of Materials science & technology 2000年第4期16卷 427-430页

作者： Xiaodong WANG, Hangquan LI and Riguang JIN (school of Materials science and Engineering, Beijing university of {3. technology, Beijing 100029, China) school of Materials science and Engineering Beijing University of Chemical Technology Beijing 100029 China

The miscibility and phase behavior of the blends of polyoxymethylene (POM)/Novolak were investigated by the cloud point method, which showed that the POM/Novolak blends exhibited a lower critical solution temperature. The melting point of POM decreased when diluted with Novolak. From the melting temperature depression of POM, a negative interaction parameter (x) between POM and Novolak was obtained. The IR spectrum revealed that the miscibility between POM and Novolak was caused by the specific interaction between the OH groups of Novolak and the ether oxygen atoms of POM. The morphology of the blends investigated by polarized light microscopy showed that the size of spherulites of POM was sharply decreased by its mixing with Novolak. This suggests that Novolak be used as a compatibilizer for POM.

关键词： POM Study on the Miscibility and Phase Behavior of Polyoxymethylene with Novolak