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101.
We use the topological tool of Nielsen fixed-point theory to study the controllability of perturbed linear control processes whose control space can be reduced to a finite-dimensional one. These methods produce a lower bound on the number of controls that achieve a given target. We concentrate particularly on the case where the perturbation has sublinear growth, and we exhibit examples of multiple controls of various types that are detected by the Nielsen theory method.This research was partly supported by the Research Grant Teoria del Controllo dei Sistemi Dinamici, Ministero della Pubblica Istruzione, Roma, Italy. 相似文献
102.
Tom Kennedy 《Journal of statistical physics》1990,59(1-2):195-220
A fixed-point equation on an infinite-dimensional space is proposed as an alternative to the usual definition of the infinite-volume limit in discrete lattice spin systems in the high-temperature phase. It is argued heuristically that the free energy and correlation functions one obtains by solving this equation agree with the usual definitions of these quantities. A theorem is then proved that says that if a certain finite-volume condition is satisfied, then this fixed-point equation has a solution and the resulting free energy is analytic in the parameters in the Hamiltonian. For particular values of the temperature this finite-volume condition may be checked with the help of a computer. The two-dimensional Ising model is considered as a test case, and it is shown that the finite-volume condition is satisfied for0.77
critical. 相似文献
103.
We formulate the super-KMS condition suggested by Connes and Kastler, in the context of entire cyclic cohomology of quantum algebras. We show that the Chern character of Jaffe, Lesniewski, and Osterwalder — associated by Kastler to a super-KMS functional — satisfies the entire growth condition. Hence, a super-KMS functional defines a cocycle for the entire cyclic cohomology of quantum algebras.Supported in part by the National Science Foundation. 相似文献
104.
105.
The oscillating conditions for a series piezoelectric quartz crystal (SPQC) are proposed and verified experimentally. The influence of the cell constant and oscillator phase on the oscillational ability of the SPQC was investigated. It is shown that the SPQC possesses excellent oscillational ability in low or high conductivity solutions, but in solution of intermediate conductivity, the oscillational ability decreases with increasing oscillator phase or decreasing cell constant, sometimes resulting in a cease-to-oscillate zone. The SPQC was applied to determine the urease activity in plant seeds with a detection limit of 0.004 U ml−1, based on the change in conductivity. 相似文献
106.
Bao Gia Nguyen 《Journal of statistical physics》1987,49(1-2):235-243
A study is made of the gap exponents for percolation processes with the triangle condition in the subcritical region. It is show that the gaps are given by
t
=2 fort=2, 3,. Scaling theory predicts thatP
p
(¦C
0¦S(p))–(p
c
–p) andE
p
(1/¦C
0¦; ¦C
0¦S(p))–(p
c
–p)3, whereS(p) is the typical cluster size. It is found that (p
c
–p)P
p
(|C
0S(p)
1–)(p
c
–p)1–2 and (p
c
–p)3E
p
(1/|C
0|;|C
0|S(p)
1–))(p
c
–p)3–4. 相似文献
107.
Studies on chemical modification of demineralized bone matrix (DBM) have opened new arenas in the field of clinical orthopedics owing to its potential osteoinductivity with desired chemical functionality. To widen its usage to biomolecular delivery, graft polymerization of glycidylmethacrylate onto DBM was carried out by a free-radical initiating process using ceric ammonium nitrate as an initiator. The evidence of the grafting reaction was examined by chemical analysis using Fourier transform IR spectroscopy. The grafting condition was standardized by regulating the reaction parameters such as the concentrations of the backbone, the monomer and the initiator, the polymerization temperature and time. The optimum polymerization temperature and time to have the maximum grafting yield were 40 °C and 3 h, respectively. The percentage of grafting and the percentage of grafting efficiency were determined as a function of the reaction parameters, and both were found to increasing initially and thereafter decrease in most of the cases. The grafting results are discussed in a detailed fashion and a reaction mechanism is proposed. 相似文献
108.
109.
考察了反应温度、气体空速和进料中CH4:O2比值对Mo2C/Al2O3催化的POM反应制合成气的影响.结果发现较高的温度具有较高的甲烷转化率、CO和H2的选择性;而在较低的温度下,对CO的选择性比对H2的影响更大.反应气体的空速较小时对于甲烷的转化率、CO和H2的选择性是有利的;而在较高的气体空速下,氢气的选择性则更低.进料中CH4:O2比值稍高于2:1时有利于获得高的甲烷转化率、CO和H2的选择性.并且还可以增加催化剂的稳定性.当CH4:O2比值低于2:1时.甲烷转化率、CO和H2选择性随反应的进行急剧下降.而当此比值调整到高于2:1时.转化率和选择件都可以得到恢复。 相似文献
110.
以硫酸铝液为原料,以氨水、氢氧化钠和铝酸钠为碱沉淀剂,采用pH摆动法制备了高比表面积、大孔径、窄孔分布、大孔体积氧化铝,考察了沉淀剂、沉淀温度及沉淀时酸侧pH值对氧化铝物性的影响,并对pH摆动法与等pH沉淀法的结果进行了比较.结果表明,通过改变制备参数可以获得高比表面积、大孔体积的氧化铝,当沉淀温度为70℃,pH摆动3或4次时,氧化铝的孔体积可高达1.0ml/g,比表面积仍大于300m2/g.用pH摆动法制得的样品比用等pH沉淀法制得的样品容易酸溶,对挤压成型有利.不同样品在酸溶液中的分散性表明,用氨水沉淀剂可获得相对较小的沉淀粒子.改变沉淀时酸侧的pH值,可导致沉淀粒子的结构发生变化. 相似文献