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Characteristic parameters and operational curves of g-Al_2O_3 nanofiltration membranes

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Chinese Science Bulletin 2003年第10期48卷 971-974页

作者： XIONG Rongchun, LEI Xiaodong & WEI Gang beijing university of chemical technology, beijing 100029, China

The g-Al2O3 nanofiltration membranes were manufactured by the sol-gel technique. The result of N2 adsorption and desorption test indicates that the characteristic parameters of the membranes: BJH desorption average pore diameter, BJH desorption cumulative volume of pores and BET surface area are about 3.9 nm, 0.33 cm3/g and 245 m2/g respectively, and the pore size distribution is very narrow. The operational curves of g-Al2O3 nanofiltration membranes of the Ca2+ retention rate vs the trans-membrane pressure, feed concentration of solution treated and pH of solution treated were studied for the first time. It is found that the retention rate for Ca2+ increases with the transmembrane pressure increasing and decreases with the feed concentration of CaCl2 solution increasing. The retention of Ca2+ is very much dependent on the pH of the solution. Minimal Ca2+ retention rate is found at the isoelectric point (pH = 7.5).

关键词：特征参数操作曲线 γ-Al2O3 纳米过滤膜拜耳长度 Ca^2+ 三氧化二铝钙离子吸附

Chiral separation of racemic drugs using molecular imprinting

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Progress in Natural Science:Materials International 2002年第12期12卷 22-25页

作者： LEI Jiandu and TAN Tianwei(Department of Biochemical Engineering, School of chemical Engineering, beijing university of chemical technology, beijing 100029, China) beijing Univ Chem Technol Sch Chem Engn Dept Biochem Engn Beijing 100029 Peoples R China

Molecularly imprinted polymers (MIPs) of (S)-ketoprofen and (S)-naproxen are prepared using non-covalent imprint’ ing in the presence of template molecules. The prepared MIPs are used as the chiral stationary phase to separate ramemic naproxen and ke-toprofen. The results show that racemic naproxen and ketoprofen are efficiently resolved on MIPs. The effect of concentration of acetic acid in the mobile phase is studied, and the data are analyzed using the affinity chromatography model, and the close agreement is achieved between the simulated and experimental curves. The results suggest that the affinity chromatography mechanism controls the retention in this system. Moreover, the affinity chromatography equilibrium constants on (S)-naproxen and (S)-ketoprofen are estimated.

关键词： molecular imprinting polymer chiral separation naproxen affinity chromatography model.

OVERLAPPING SPEECH SEPARATION BY REPEATING PITCH ADDING

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OVERLAPPING SPEECH SEPARATION BY REPEATING PITCH ADDING

第八届全国人机语音通讯学术会议

作者： WANG Tian, ZHAO Shuqing College of infonnation science and technology, beijing university of chemical technology, beijing, 100029, China College of information science and technology, beijing university of chemical technology, beijing, 100029, China

An algorithm to separate overlapping speech signals is proposed in the paper. The first step of the algorithm is to detect the pitch of overlapping speech signals. The second step, the key of the method, is repeating pitch adding, which is done by adding the overlapping speech and the next period of it. And the last step is to judge the adscription of each formant of the overlapping speech. By making a little change to this algorithm, a similar method called repeating pitch subtracting is also proposed. Finally, some experiments for evaluating the performance of the algorithms are made. The input signals of these experiments include single word, double words and long sentences.

关键词： Speech enhancement Speech separation Pitch detecting

Grain Growth Kinetics of SnO_2 Nanocrystals Synthesized by Precipitation Method

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Journal of Wuhan university of technology(Materials Science) 2010年第6期25卷 929-934页

作者：宋晓岚 School of Minerals Processing and Bioengineering Central South University

Monodispersed spheroidal SnO2 nanocrystals with the grain size of 8-30 nm were synthesized by the precipitation method using SnCl4·5H2O （stannic chloride hydrate） as raw *** scanning calorimetry/thermogravimetry （DSC/TG）,X-ray diffraction （XRD） and transmission electron microscope （TEM） were used to characterize the structure of SnO2 *** influences of the calcination temperature and time on the lattice constant,the lattice distortion and the grain size of SnO2 nanocrystals were discussed based on the XRD *** grain growth kinetics of SnO2 nanocrystals during calcination process was simulated with a conventional grain growth model which only took into account of diffusion and with a new isothermal model proposed by our group,which took into account of both diffusion and surface *** conventional model,the grain growth rate constant of SnO2 crystals is 1.55×104nm5/min with a pre-exponential factor of 5 and an activation energy of 108.62 kJ/*** with the convention model,the new isothermal model is more realistic in reflecting the grain growth behavior of SnO2 nanocrystals during the calcination *** indicates that the grain growth of SnO2 nanocrystals is controlled by both diffusion and reaction factors,and the effect of surface reactivity on the grain growth of SnO2 nanocrystals could not be ignored.A combined activation energy estimated with the new isothermal model is 53.46 kJ/mol.

关键词： SnO2 nanocrystal precipitation method calcination grain growth kinetics

RTD-A控制器参数性能分析及在线模糊自整定

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上海交通大学学报 2011年第8期45卷 1167-1171页

作者：楚纪正杜彬陈娟北京化工大学信息科学与技术学院北京100029

为了减少RTD-A控制器的参数调节难度,增强其实用性,分析了RTD-A控制器中需要整定的4个参数,即系统鲁棒性θR、设定值跟踪θT、干扰抑制θD和全局收敛性θA对系统性能的影响.结果表明:当θT和θA在一定范围内取定值时,对系统控制结果不... 详细信息

为了减少RTD-A控制器的参数调节难度,增强其实用性,分析了RTD-A控制器中需要整定的4个参数,即系统鲁棒性θR、设定值跟踪θT、干扰抑制θD和全局收敛性θA对系统性能的影响.结果表明:当θT和θA在一定范围内取定值时,对系统控制结果不会产生明显的影响;而θR和θD的整定则能够改善系统模型失配和未知扰动等问题.为此,提出了一种基于模糊逻辑的控制器参数θR和θD的在线自整定方法.该方法首先建立了控制器参数的模糊控制规则,然后,根据模糊控制规则进行模糊推理,实现了参数θR和θD的在线模糊自整定.仿真实验结果表明,与手工设定参数方法相比,本文提出的参数在线模糊自整定方法能够简化参数的整定步骤,提高RTD-A控制器的性能.

关键词： RTD-A控制器模糊控制参数自整定

反荷离子及制备方法对Keggin型杂多化合物结构和性质的影响

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石油化工 2008年第3期37卷 216-221页

作者：郭晓俊黄崇品北京化工大学化工资源有效利用国家重点实验室北京100029

采用喹啉沉淀法和共沉淀法制备了一系列不同反荷离子的Keggin型杂多化合物(HPCs)催化剂,通过N2吸附-脱附、傅里叶变换红外光谱、X射线衍射、31P固体魔角核磁共振谱、扫描电子显微镜和NH3-程序升温脱附表征,研究了反荷离子和制备方法对H... 详细信息

采用喹啉沉淀法和共沉淀法制备了一系列不同反荷离子的Keggin型杂多化合物(HPCs)催化剂,通过N2吸附-脱附、傅里叶变换红外光谱、X射线衍射、31P固体魔角核磁共振谱、扫描电子显微镜和NH3-程序升温脱附表征,研究了反荷离子和制备方法对HPCs催化剂结构和性能的影响,并考察了该系列催化剂在甲基丙烯醛(MAL)氧化为甲基丙烯酸(MAA)反应中的催化活性。实验结果表明,添加Cs+提高了HPCs催化剂的活性;Cu2+与Cs+的协同作用提高了HPCs催化剂的氧化还原能力和结构稳定性,MAL的转化率达到88.6%,MAA的选择性达到94.9%;含La3+的HPCs催化剂具有较强的酸性,MAA的选择性较高;与共沉淀法相比,喹啉沉淀法制备的HPCs催化剂具有较大的比表面积和较高的MAL氧化活性。

关键词：反荷离子杂多化合物甲基丙烯醛甲基丙烯酸喹啉沉淀法共沉淀法

Approach to predict partitioning of organic compounds from air into airborne particulate

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Science Bulletin 2005年第16期 26-28页

作者： SUN Cong & FENG Liu Department of Environmental Engineering, College of chemical Engi-neering, beijing university of chemical technology, beijing 10029, China

Based on the theoretical linear solvation energy relationship and quantum chemical descriptors computed by AM1 Hamiltonian, a new approach was developed to predict the partitioning of some organic compounds between the airborne particulate and air. It could be successfully used to study the partitioning of organic compounds from air into airborne particulate, and evaluate the potential risk of or-ganic compounds.

关键词： organic compound quantum chemical descriptor parti-tioning coefficient QSPR.

Continuous Improvement Method in Risk Management

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Continuous Improvement Method in Risk Management

2012管理创新、智能科技与经济发展研讨会

作者： Anling ZHANG,Jing ZHAO 1 beijing university of chemical and technology,beijing,China

risk management is the main part of the project management,the purpose is to maximize the active pursuit and minimize the adverse *** Innovation ideas were introduced into project risk management;it reflected the significance of management thinking and *** consists of a series of processes,methods and tools in continual Innovation of project-related risk *** provides a proactive and rational environment *** article discussed capability maturity models,features,procedures and values for the continuous improvement of project risk management.

关键词： Project Risk Management Continuous Improvement Risk Management Capability Maturity Models

Fractional System Identification Based on Improved NLJ Algorithm

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Fractional System Identification Based on Improved NLJ Algor...

第24届中国控制与决策会议

作者： ZHANG Ming , LI Dazi School of Information Science and technology, beijing university of chemical technology, beijing 100029

This paper presents an improved new Luus-Jaakola （NLJ） algorithm which is applied to the fractional order system identification. The discretization of the fractional order system is the precondition of the system identification. However, whether it is based on the definition or the direct approximation, the discretization will increase the complexity of the system architecture and make the system identification much more difficult. In this context, the traditional NLJ algorithm still appears to be of low efficiency and poor stability of the identification result. To address this problem, this article introduces the concept of bi-directional iterative calculation. By comparing the fitting errors, the set of parameters resulting to the smaller error is selected as the initial value of the next iteration, through which the identification efficiency has been improved greatly. Meanwhile, the improved algorithm is applied to two forms of fractional identification with constrained and unconstrained, respectively, just in order to verify the correctness and efficiency of the improved algorithm.

关键词： New Luus-Jaakola (NLJ) fraction identification bi-directional iteration