Stabilization of Rössler chaotic dynamical system using fuzzy logic control algorithm

This paper proposes a fuzzy logic control algorithm (FLCA) to stabilize the Rössler chaotic dynamical system. The fuzzy logic control system is based on a Takagi-Sugeno-Kang inference engine and the stability analysis in the sense of Lyapunov is carried out using Lyapunov’s direct method. The new FLCA is formulated to offer sufficient inequality stability conditions. The asymptotic complexity of our algorithm is analyzed and proved to be lower in comparison with that of linear matrix inequality-based FLCAs. A set of simulation results illustrates the effectiveness of the proposed FLCA.     

2-氯-5-氯甲基吡啶在气升环流反应器中的合成研究

A new process for the direct chlorination of 2-chloro-5-methylpyridine to yield 2-chloro-5-chloro-methylpyridine in an airlift loop reactor (ALR) has been studied.Five main reaction conditions including TR,na/ns,cp,Qg and dD/dR were optimized.The average molar yield and purity of 2-chloro-5-chloromethylpyridine obtained were 79% and 98.5% respectively under the optimum operating conditions.Finally,the efficiency for the preparation of 2-chloro-50chloromethylpyridine with ALR and stirred tank reactor(STR) respectively was compared.     

电纺直写制备聚己内酯支架形貌及精度

作为一种新型的微纳制造技术，熔体直写电纺被广泛用于组织工程支架的可控制备,有序的纤维沉积是该领域应用的前提条件。对于支架成型精度的探究，本文使用生物可降解材料聚己内酯（PCL），采用自行设计的熔体电纺三维可控成型设备进行实验，考察了纤维间距对二维并行纤维沉积形貌及成型精度的影响，以及纺丝电压和网格大小对三维网格结构形貌及精度影响。结果表明，随着并行纤维设定距离的增大，纤维的沉积误差减小，并最终趋于平稳。对于三维网格结构，随电压的增加，最大沉积层数量先增大后减小，当纺丝电压为6kV时达到最大沉积层数15层。成型精度误差先减小后增大，当纺丝电压为7kV时，精度最高误差小于5%。随设定网格边长的增大，沉积层数不断增大。成型精度逐渐提高，当网格边长大于等于1.5mm时，沉积误差趋于稳定，并维持在5%左右。     

纳米氧化锌的制备与表征

对传统的直接沉淀法进行了改进 ,对反应温度、搅拌速度、投料方式及洗涤条件等多种因素对产物纳米氧化锌的影响进行了研究。结果表明 ,改进的直接沉淀法制备纳米氧化锌具有工艺简单、成本较低 ,能够得到六方晶系、球形 ,粒径约为 15～ 2 5nm的纳米氧化锌     

Solar Photocatalytic Degradation of Textile Dyes in TiO2 Suspended Solutions

The degradation and decolourization of direct dye (Everdirect supra turguoise blue, FBL), acidic dye (Isolan orange S-RL) and vat dye (Indanthren red FBB) have been investigated by solar/TiO2 process. The effects of solution pH, dye concentration, dosage of TiO2 and nano-size of TiO2 have been studied. The increase in initial pH (3, 5 and 11) and dye concentration decrease the removal rate. The treatment for FBB and FBL dye solutions is more efficient than that of S-RL.Under optimum conditions, the color removal is found to be almost complete for FBB and FBL while that of S-RL also reaches 95%. Langmuir adsorption isotherm and modified Langmuir-Hinshelwood kinetic model (L-H model) have been fitted to the experimental data and found to correlate the adsorption patterns as well as the kinetics of the dyes studied.     

四旋翼直升机姿态系统的直接自修复控制

当四旋翼直升机执行器突发故障或突受干扰时,利用直接自修复控制技术,设计一种基于直接自适应滑模控制的四旋翼直升机姿控系统,使其在故障或干扰信息未知的情况下,仍能保持稳定并且跟踪上理想输出信号.系统的稳定性和跟踪性能是由Lyapunov稳定性定理来确保的,这体现在参数更新律的设计过程中.最后在3DOFhover实验平台上验证了该方法的有效性,同时将该方法与LQR方法作比较,进一步证明了所提算法的优越性.     

苯和乙烯一步法合成苯乙烯反应研究

首次采用苯和乙烯在无氧存在下, 于多种固体酸和金属负载HZSM-5分子筛催化剂上反应直接得到苯乙烯与其它固体酸相比, HZSM-5分子筛催化剂表现出最高的反应活性和较高的对苯乙烯的选择性。HZSM-5分子筛负载不同金属后, 苯乙烯的选择性均有明显提高, 其中以Co/HZSM-5、Fe/HZSM-5和Pd/HZSM-5催化剂显示出较高的反应活性和苯乙烯选择性。反应温度、苯烯比、金属负载量、液空速、催化剂的焙烧及还原温度均会不同程度地影响反应转化率和产物分布。     

直接凝固注模成型Si_3N_4及SiC陶瓷──基本原理及工艺过程

直接凝固注模成型（ｄｉｒｅｃｔｃｏａｇｕｌａｔｉｏｎｃａｓｔｉｎｇ，ＤＣＣ）是一种崭新的（准）净尺寸陶瓷成型方法。本文报道了采用此法成型Ｓｉ_３Ｎ_４及ＳｉＣ陶瓷的基本原理和工艺过程。ＤＣＣ成型工艺过程为把高固相含量低粘度的陶瓷浆料浇注到无孔模具中，事先加入到浆料中的生物酶及化学物质通过改变浆料的ｐＨ或电解质浓度来改变浆料的胶体化学行为，从而使浆料原位凝固，得到有足够脱模强度的陶瓷坯体。ＤＣＣ成型的特点为坯体密度高（理论密度的５５％～７０％），坯体均匀，不用或只需少量的有机添加剂（少于１％），可成型大尺寸、复杂形状、高可靠性的陶瓷部件。     

Prediction of Experimental Methanol Decomposition Rates on Platinum from First Principles

A microkinetic model for methanol decomposition on platinum is presented. The model incorporates competitive decomposition pathways, beginning with both O–H and C–H bond scission in methanol, and uses results from density functional theory (DFT) calculations [Greeley and Mavrikakis, J. Am. Chem. Soc. 124 (2002) 7193, Greeley and Mavrikakis, J. Am. Chem. Soc. 126 (2004) 3910]. Results from reaction kinetics experiments show that the rate of H₂ production increases with increasing temperature and methanol concentration in the feed and is only nominally affected by the presence of CO or H₂ with methanol. The model, based on the values of binding energies, pre-exponential factors and activation energy barriers derived from first principles calculations, accurately predicts experimental reaction rates and orders. The model also gives insight into the most favorable reaction pathway, the rate-limiting step, the apparent activation energy, coverages, and the effects of pressure. It is found that the pathway beginning with the C–H bond scission (CH₃OH→H₂COH→HCOH→CO) is dominant compared with the path beginning with O–H bond scission. The cleavage of the first C–H bond in methanol is the rate-controlling step. The surface is highly poisoned by CO, whereas COH appears to be a spectator species.     

对二甲苯直接电解氧化反应的研究

研究了在有机溶剂、支持电解质和碳棒存在下，对二甲苯的直接电解氧化反应，使用GC－MS方法分析鉴定了主要电解氧化产物，讨论了电解氧化产物成分随电解时间的变化规律，提出了对二甲苯的直接电解氧化反应过程。