首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
García Guirao and Lampart (J Math Chem 48:66–71, 2010; J Math Chem 2 48:159–164, 2010) said that for non-zero couplings constant, the lattice dynamical system is more complicated. Motivated by this, in this paper, we prove that this coupled lattice system is distributionally (p, q)-chaotic for any pair 0?≤ p?≤ q?≤ 1 and its principal measure is not less than ${\frac{2}{3} + \sum_{n=2}^{\infty} \frac{1}{n} \frac{2^{n-1}}{(2^{n}+1)(2^{n-1}+1)}}$ for coupling constant ${0 < \epsilon < 1}$ .  相似文献   

2.
García Guirao and Lampart in (J Math Chem 48:159–164, 2010) presented a lattice dynamical system stated by Kaneko in (Phys Rev Lett 65:1391–1394, 1990) which is related to the Belusov–Zhabotinskii reaction. In this paper, we prove that for any non-zero coupling constant $\varepsilon \in (0, 1)$ , this coupled map lattice system is distributionally $(p, q)$ -chaotic for any pair $0\le p\le q\le 1$ , and that its principal measure is not less than $(1-\varepsilon )\mu _{p}(f)$ . Consequently, the principal measure of this system is not less than $$\begin{aligned} (1-\varepsilon )\left( \frac{2}{3}+\sum \limits _{n=2}^{\infty }\frac{1}{n}\frac{2^{n-1}}{(2^{n}+1) (2^{n-1}+1)}\right) \end{aligned}$$ for any non-zero coupling constant $\varepsilon \in (0, 1)$ and the tent map $\Lambda $ defined by $$\begin{aligned} \Lambda (x)=1-|1-2x|,\quad x\in [0, 1]. \end{aligned}$$   相似文献   

3.
In García Guirao and Lampart (J Math Chem 48:159–164, 2010) presented a lattice dynamical system stated by Kaneko (Phys Rev Lett 65:1391–1394, 1990) which is related to the Belusov–Zhabotinskii reaction. In this note, we give an example which shows that the proofs of Theorems 3.1 and 3.2 in [J Math Chem 51:1410–1417, 2013] are incorrect, and two open problems.  相似文献   

4.
5.
In this paper we present a lattice dynamical system stated by Kaneko in (Phys Rev Lett, 65: 1391–1394, 1990) which is related to the Belusov-Zhabotinskii reaction. We prove that this CML (Coupled Map Lattice) system has positive topological entropy for zero coupling constant.  相似文献   

6.
7.
Garca Guirao and Lampart (J Math Chem 48:66–71, 2010; J Math Chem 48:159–164, 2010) said that for non-zero couplings constant, the lattice dynamical system is more complicated. Motivated by this, in this paper, we prove that this coupled map lattice system is Li–Yorke chaotic for coupling constant ${0 < \epsilon <1 }$ .  相似文献   

8.
9.
This paper is concerned with the following system which comes from a lattice dynamical system stated by Kaneko in (Phys Rev Lett 65:1391–1394, 1990) and is related to the Belusov–Zhabotinskii reaction: $$\begin{aligned} x_{n}^{m+1}=(1-\varepsilon )f(x_{n}^{m})+\frac{1}{2}\varepsilon \left[ f(x_{n-1}^{m})+f(x_{n+1}^{m})\right] , \end{aligned}$$ x n m + 1 = ( 1 ? ε ) f ( x n m ) + 1 2 ε [ f ( x n ? 1 m ) + f ( x n + 1 m ) ] , where $m$ m is discrete time index, $n$ n is lattice side index with system size $L$ L (i.e., $n=1, 2, \ldots , L$ n = 1 , 2 , … , L ), $\varepsilon $ ε is coupling constant, and $f(x)$ f ( x ) is the unimodal map on $I$ I (i.e., $f(0)=f(1)=0$ f ( 0 ) = f ( 1 ) = 0 and $f$ f has unique critical point $c$ c with $0<c<1$ 0 < c < 1 and $f(c)=1$ f ( c ) = 1 ). It is proved that for coupling constant $\varepsilon =1$ ε = 1 , this CML (Coupled Map Lattice) system is chaotic in the sense of Li–Yorke for each unimodal selfmap on the interval $I=[0, 1]$ I = [ 0 , 1 ] .  相似文献   

10.
A well-defined N-heterocyclic carbene (NHC)–palladium chloride–imidazole complex exhibited high catalytic activity in the coupling reaction of arylboronic acids with carboxylic acid anhydrides in pure water under mild conditions. Under the optimal conditions, all reactions gave the desired coupling products in moderate to high yields.  相似文献   

11.
Research on Chemical Intermediates - We have developed a simple and efficient catalytic protocol composed of hollow palladium-poly(N-vinylpyrrolidone)-nano zero valent iron and H5PMo10V2O40...  相似文献   

12.
Lei Zhu  Yue-Mei Ye  Li-Xiong Shao 《Tetrahedron》2012,68(10):2414-2420
We report herein a well-defined NHC–Pd(II)–Im (NHC=N-heterocyclic carbene; Im=1-methylimidazole) complex catalyzed C–N coupling of primary amines with aryl chlorides. Under the optimal reaction conditions, a variety of primary amines can be coupled with aryl chlorides to give the amination products in good to high yields within 4 h. It is worthy of noting here that the NHC–Pd(II)–Im complex showed especially high catalytic activity toward challenging sterically hindered substrates including both of aryl amines and aryl chlorides. In addition, alkyl amines were also proved to be suitable reaction partners to give the corresponding amination products in good to high yields.  相似文献   

13.
Pentaquadrupole (QqQqQ) mass spectrometry is used to explore the abilities of gaseous SFn+ (n = 1–5) ions to form adducts and dimers with three π-electron rich molecules—benzene, acetonitrile, and pyridine, whereas ab initio calculations estimate most feasible structures, bond dissociation energies (BDEs), and reaction enthalpies of the observed products. With benzene, SF+ reacts by net H-by-SF replacement. As suggested by the calculations, this novel benzene reaction forms ionized benzenesulfenyl fluoride, C6H5–SF, via a Wheland-type intermediate that spontaneously loses a H atom. SF3+ forms a rare, loosely bonded π complex with benzene, [Bz ⋯ SF3]+, which is stable toward both H and HF loss. No dimer, Bz2SF3+, is formed. According to calculations, an unsymmetrically bonded, π-coordinated Bz2SF3+ dimer exists, i.e. (Bz–SF3 ⋯ Bz)+, but its formation from [Bz ⋯ SF3]+ is endothermic; hence, thermodynamically unfavorable. With acetonitrile, SF2, SF3+, and SF5+ form both adducts and dimers. CH3–C·N–SF2+ (a new distonic ion) and CH3CN–SF5+ are covalently bonded, but CH3CN ⋯ SF3+ is loosely bonded. The binding natures of the acetonitrile adducts are reflected in the dimers; [CH3CN–SF2 ⋯ NCCH3] and [CH3CN–SF5 ⋯ NCCH3]+ are unsymmetrically bonded, whereas [CH3CN ⋯ SF3 ⋯ NCCH3]+ is symmetrically and loosely bonded. Such dimers as [CH3CN ⋯ SF3 ⋯ NCCH3]+ are ideal for measurements of ion affinity via the Cooks’ kinetic method. With pyridine, only SF3+ forms adduct and dimer. Py–SF3+ is covalently bonded through nitrogen; [Py ⋯ SF3 ⋯ Py]+ is loosely but unsymmetrically bonded. The unsymmetric 2.28 and 2.44 Å long N–S bonds in [Py ⋯ SF3 ⋯ Py]+, which are expected to rapidly interconvert, result likely from steric hindrance that forces orthogonal alignment of the two pyridine rings. Most observed adducts and dimers display relatively high BDEs, i.e. they are formed in thermodynamically favorable reactions. The extents of dissociation of the adducts and dimers observed in MS3 experiments reflect the structures and BDEs predicted by the calculations.  相似文献   

14.
Research on Chemical Intermediates - The reaction process of a M (M?=?Mn, Fe, Co and Ni) atom associated and then interpolated into a Fe8O12 cage is calculated by using a PBE...  相似文献   

15.
IR studies of SnF2 and hept-1-yne codeposited in an argon matrix at 12 K has revealed new bands at 540, 565, 1011, 2088 and 3256 cm–1, assigned to the formation of a complex between SnF2 and the alkyne. Quantum chemical AM1 and PM3 calculations confirm this assignment to the -complex of SnF2 and the triple bond of hept-1-yne, and show that the complex forms without an activation barrier. The energy of the formation of the complex according to AM1 and PM3 calculations is 7.4 and 9.1 kcal/mol, respectively. The calculations indicate that the product of the cycloaddition of SnF2 to a triple bond, stannyrene, is significantly less stable than the -complex.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 54–56, January, 1994.  相似文献   

16.
17.
A method has been developed enabling direct analysis (i.e. after dilution only) of beer, instant coffee, milk, and milk powder by ICP–AES. Analysis of the beverages after dilution with a low concentration of HNO3 was used for accurate determination of essential minor and trace elements (Ca, Mg, K, P, S, and Zn). Selenium, introduced as the hydride, was determined simultaneously with the other non-hydride-forming elements using the commercial multi-mode sample-introduction system (MSIS). To obtain accurate results, however, some simple pre-treatment was needed. Analysis was also performed after microwave-assisted decomposition of the samples. Three different modes of sample-preparation, i.e. dilution only, partial decomposition (aqua regia treatment), and complete decomposition were compared. The results obtained by use of the three different sample-preparation methods were in very good agreement. Results from analysis of certified reference material (SRM 1459 non-fat milk powder) also verified the accuracy of the methods. The limit of detection obtained for Se using dual-mode sample introduction was 0.5 ng mL–1, which corresponds to approximately 2 ng g–1 in beer and approximately 4 ng g–1 in coffee and milk when using the recommended procedure.  相似文献   

18.
A rapid and sensitive method has been developed for the simultaneous detection of cyromazine and melamine in chicken eggs using the quick, easy, cheap, effective, rugged and safe (QuEChERS) method coupled with liquid chromatography–tandem mass spectrometry (LC–MS/MS). The optimal extraction solvent for the liquid–liquid extraction was 5 mL of acetonitrile with a 0.1 M hydrochloric acid aqueous solution (99.5:0.5, v/v). The extract was cleaned with 0.5 g of anhydrous magnesium sulfate and 10 mg of graphitized carbon black. The analysis of cyromazine and melamine was accomplished by combining the use of an anion exchange LC column with tandem mass spectrometry in the positive electrospray ionization mode with selected reaction monitoring mode (SRM). The detection limits were 1.6 ng g−1 for cyromazine and 8 ng g−1 for melamine, and the quantitation limits were 5.5 ng g−1 for cyromazine and 25 ng g−1 for melamine. The recoveries of cyromazine and melamine in the spiked egg samples were 83.2% and 104.6%, respectively, with an relative standard deviation (RSD) of less than 18.1%. The intra-day and inter-day precisions, represented by the RSD, ranged from 1.5% to 8.8% and 6.8% to 14.3%, respectively. The proposed method was tested by analyzing chicken eggs from the markets and from the veterinary medicine laboratory. The concentrations of cyromazine and melamine detected in these samples were in the range of 20–94 ng g−1. The results demonstrated that the QuEChERS method combined with LC–MS/MS is a simple, rapid and inexpensive method for the analysis of cyromazine and melamine in eggs.  相似文献   

19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号