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Search Results: 1 - 10 of 137313 matches for " LI Bao-Tong "
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Sliding mode controller design and simulation study for discrete time systems

WEI Li-xia,CUI Bao-tong,

计算机应用研究 , 2007,
Abstract: 针对不确定性离散时间系统,分析和设计了一类变结构控制器。当存在外界干扰和不确定性时,系统状态也是全局有界稳定的。一个新的切换面作为系统的输出信号被提出,特别用来设计滑模控制器。系统状态一旦进入到准滑动模态,就对设备参数变化和外界干扰显示出强的鲁棒性,因为控制器的设计完全考虑了边界层的影响。外推法被用来估计不确定离散时间系统的不确定值。两种方法均有效地消除了系统的抖振,确保了系统的稳定性,且保证了变结构控制系统良好的品质。最后,仿真结果证实了所提出方法的有效性。
Characteristics and Mechanism for the Simons Electrochemical Fluorination of Methanesulfonyl Fluoride

XU Wen-lin
, LI Bao-tong, WANG Da-wei, WANG Ya-qiong

- , 2017, DOI: 10.13208/j.electrochem.161043
Abstract: 摘要 选择CH3SO2F电化氟化制备CF3SO2F过程为研究系统,研究了电化氟化过程操作电压和反应时间的关系、操作条件对氟化产物组成的影响规律以及Ni电极在电化氟化过程的变化情况. 实验结果表明,Simons电化学氟化过程主要由三个步骤组成:F-在阳极发生电化学氧化反应生成F,该步骤是Simons电化学氟化过程的控制步骤;在Ni电极上生成的F与Ni或NiF2反应生成高价NiFn (n≥3),NiFn为Simons电化学氟化过程的氟化剂;NiFn可以在电极/电解液界面与有机物发生氟化反应生成氟化产物,也可以发生分解反应生成游离F2,NiFn与有机物发生氟化反应的机理与用CoF3等为氟化剂氟化有机物的机理相同. 但NiFn的反应活性比CoF3高,且在实验条件下极不稳定.
The characteristics and mechanism for the Simons electrochemical fluorination processes were investigated during the electrochemical fluorination of CH3SO2F to CF3SO2F. The results showed that the reaction mechanism for the electrochemical fluorination of organic compounds to organic fluorides was the same as that of chemical fluorination processes using fluorinating agents such as CoF3. The electrochemical fluorination in anhydrous HF was a heterogeneous process, and nickel fluorides on the surface of the nickel anode played the role of a mediator in the Simons process to transfer oxidation potential from the anode to the substrate and fluorine from HF to the organic substance. Nickel fluorides were formed electrochemically on the surface of the nickel anode by oxidation of Ni in anhydrous HF to a high valence (with the oxidation stage more than +2) nickel fluorides. The fluorinating agents in electrochemical fluorination processes were NiFn(n≥3), high valences of nickel produced at the anode, which is much more reactivie than CoF3 and instable under the experimental conditions. The decomposion of NiFn to F2 would take place, and NiFn could also react with organic fluoride. Because F2 is a strong fluorinating agent, NiFn could be decomposed into low molecular weight organic compounds fluorinated products, leading to low current efficiency in process yield and by-products. Therefore, an effective method to improve the process is by increasing the molar ration of organic matter to NiFn on the anode/electrolyte interface
Improved exponential stability criteria for uncertain neutral system with nonlinear parameter perturbations

Fang Qiu,Bao-Tong Cui,

国际自动化与计算杂志 , 2010,
Abstract: This paper investigates the problem of robust exponential stability for neutral systems with time-varying delays and nonlinear perturbations. Based on a novel Lyapunov functional approach and linear matrix inequality technique, a new delay-dependent stability condition is derived. Since the model transformation and bounding techniques for cross terms are avoided, the criteria proposed in this paper are less conservative than some previous approaches by using the free-weighting matrices. One numerical example is presented to illustrate the effectiveness of the proposed results.
Dissipativity Analysis of Neural Networks with Time-varying Delays
Yan Sun,Bao-Tong Cui,

国际自动化与计算杂志 , 2008,
Abstract: A new definition of dissipativity for neural networks is presented in this paper.By constructing proper Lyapunov func-tionals and using some analytic techniques,sufficient conditions are given to ensure the dissipativity of neural networks with or without time-varying parametric uncertainties and the integro-differential neural networks in terms of linear matrix inequalities.Numerical examples are given to illustrate the effectiveness of the obtained results.
Adaptive synchronization in an array of asymmetric coupled neural networks

Gao Ming,Cui Bao-Tong,

中国物理 B , 2009,
Abstract: This paper investigates the global synchronization in an array of linearly coupled neural networks with constant and delayed coupling. By a simple combination of adaptive control and linear feedback with the updated laws, some sufficient conditions are derived for global synchronization of the coupled neural networks. The coupling configuration matrix is assumed to be asymmetric, which is more coincident with the realistic network. It is shown that the approaches developed here extend and improve the earlier works. Finally, numerical simulations are presented to demonstrate the effectiveness of the theoretical results.
Improved delay-dependent globally asymptotic stability of delayed uncertain recurrent neural networks with Markovian jumping parameters

Ji Yan,Cui Bao-Tong,

中国物理 B , 2010,
Abstract: In this paper, we have improved delay-dependent stability criteria for recurrent neural networks with a delay varying over a range and Markovian jumping parameters. The criteria improve over some previous ones in that they have fewer matrix variables yet less conservatism. In addition, a numerical example is provided to illustrate the applicability of the result using the linear matrix inequality toolbox in MATLAB.
Study on conveyance technologies of highyield cultivation without environmental pollution of rice

LI Bao-Tong,SHI Qing-Hu,FANG Jia-Hai,YIN Feng,XIAO Dong-Hua,
,石庆华,方加海,尹 峰,肖冬华

中国生态农业学报 , 2004,
Abstract: The used quantities of seeds, fertilizers and pesticides were decreased, the production cost was reduced by 285 yuan and the incomes from paddy were increased by 1667 yuan per hectare in the demonstrative area of production without environmental pollution of rice by a series of conveyance technologies of gymnastic cultivation of rice, using farm manure, organic manure for a special purpose of rice, applying pesticides without environmental pollution and agricultural methods, using chemical pesticides of high efficiency, low toxicity and lower residue of limited quantity against diseases, insect pests and weeds at necessary time. The residues of poisonous pesticides, heavy metal and other indexes in rice are lower than the health targets of green food. Their natural enemies such as spiders and others should be increased in paddy fields.

MO Zhi-shen,WANG Li-xiao,ZHANG Hong-fang,HAN Ping,HUANG Bao-tong,

高分子学报 , 1988,
Abstract: 用大角X-射线衍射(WAXD)方法对按嵌段聚合程序合成的聚丙烯(PP)和乙丙共聚物(EPR)的嵌段共聚物PP-EPR和PP-EPR-PP,以及相应的混合物进行对比研究.乙丙共聚物及其共混物均发现在2θ=20°处存在由EPR中PP链段引起的γ-晶型衍射峰.通过诠释X-射线衍射图,计算结晶度,微晶尺寸和晶格参数等表明,用δ-TiCl_3-Et_2AlCl催化剂获得了嵌段共聚物结构.

LI San-xi,MO Zhi-shen,ZHANG Hong-fang,PANG De-ren,HUANG Bao-tong,

高分子学报 , 1991,
Abstract: The crystallinity of ethylene/a-olefin copolymers, which was prepared by copolymerization of ethylene and a-olefins with heterogeneous Ziegler-Natta catalyst made by chemical reaction, was studied by WAXD, DSC, and PLM methods.The results of WAXD showed that the crystallite size and degree of crystallinity decrease and the parameters of unit cell increase with increase content of a-olefin in copolymers. On the other hand, the crystallite size and degree of crystallinity of the copolymers after heat treatment obviously increase, while parameters of unit cell decrease. Both the critical crystalline sequence lengthes and the value of k obtained increase in the order of EPe

WANG Li-xiao,QI Yu-chen,CHEN Dong-lin,HUANG Bao-tong,

高分子学报 , 1987,
Abstract: 用DSC研究了预期为聚丙烯-聚乙烯两嵌段共聚物(PP-PE)和相应共混物(PP+PE)在热学性能上的差异。经用不同分子量的PP和PE及其共混物进行试验后发现,由于PP和PE在结晶时出现过冷的难易不同。在共混物降温热分析曲线上,当降温速率较快时仅出现一个放热峰,而降温速率较慢时出现PP和PE各自的结晶放热峰,从而解释了文献中的不同结果。并发现共混物的PP和PE熔融、结晶温度均较组分相同的嵌段共聚物的相应温度为高;嵌段共聚物中PP和PE的△H_f值均低于均聚物的△H_f值,而PE的值降低尤甚。我们认为这与嵌段间的共价键限制嵌段活动和结晶过程有关,从而确认DSC热分析可以作为识别是否为嵌段共聚物的一种方法. 本工作的结果表明,所研究的PP-PE试样具有嵌段结构。
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