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11.
12.
András Sütő 《Communications in Mathematical Physics》1987,111(3):409-415
The spectrum (H) of the tight binding Fibonacci Hamiltonian (H
mn=
m,n+1+
m+1,n
+
m,n
v(n),v(n)=
((n–1)), 1/ is the golden number) is shown to coincide with the dynamical spectrum, the set on which an infinite subsequence of traces of transfer matrices is bounded. The point spectrum is absent for any , and (H) is a Cantor set for 4. Combining this with Casdagli's earlier result, one finds that the spectrum is singular continuous for 16.On leave from the Central Research Institute for Physics, Budapest, Hungary 相似文献
13.
Windberg E Hudecz F Marquardt A Sebestyén F Kiss A Bösze S Medzihradszky-Schweiger H Przybylski M 《Rapid communications in mass spectrometry : RCM》2002,16(9):834-839
An epitope motif, TX(1)TX(2)T, of mucin-2 glycoprotein was identified by means of a mucin-2-specific monoclonal antibody, mAb 994, raised against a synthetic mucin-derived 15-mer peptide conjugate. For determination of the epitope sequence recognised with highest affinity by mAb 994, a combinatorial approach was applied using the portioning-mixing technique excluding Cys. Antibody binding of libraries was most profound when Gln was at the X(1) position. Analytical characterisation of the TQTX(2)T library was conducted by amino acid analysis and matrix-assisted laser desorption/ionisation time-of-flight (MALDI-TOF) and electrospray ionisation Fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometric methods. Control libraries were prepared by mixing 19 individual peptides corresponding to the TQTX(2)T sequence. Thus, mixtures of 6, 10 and 19 pentapeptides were analysed and compared with the combinatorial mixture. MALDI-TOFMS was able to detect only partially the components in the 6- and 10-member mixtures, but failed to characterise a more complex 19-member mixture. In contrast, ESI-FTICRMS resolved all mixtures of higher complexity and provided direct identification at monoisotopic resolution, such as for a peptide library containing 'isobaric' lysine and glutamine (Delta m = 0.0364 Da). The results of this study suggest that ESI-FTICRMS is a powerful tool for characterisation of combinatorial peptide libraries of higher complexity. 相似文献
14.
J. Podeva P. pa
ek A. Sikora A. F. Podol'Skii 《Journal of polymer science. Part A, Polymer chemistry》1984,22(11):3343-3350
An initiation system of the anionic polymerization, intended for the syntheses of homopolymers and block copolymers with narrow molar mass distribution, was tested with styrene and isoprene. The actual initiating species, viz., the oligomeric α-methylstyryl anion, originates by the reaction of n-butyllithium with α-methylstyrene in a benzene/diethyl ether 1:1 (v:v) solvent mixture at room temperature. The homopolymers and two-block copolymers of styrene and isoprene, prepared by using this system, were characterized by light scattering, membrance osmometry, GPC, and 1H NMR spectroscopy. By using the suggested initiation system, it is possible to synthesize well-defined homopolymers and block copolymers with low polydispersity (as judged by the shape of the GPC peaks and by the values of the polydispersity index), especially in a molar mass region between 4 × 104 and 1.5 × 105 g/mol. Above the upper limit of this interval, an appropriate decrease of the diethyl ether/benzene volume ratio is recommended, though the polymerization time must then be prolonged. 相似文献
15.
Francis D. de Kőrösy 《Mikrochimica acta》1989,97(1-2):25-29
Donor or acceptor compounds in apolar organic solvents become charged at a high-field strength electrode and are driven to a surrounding low-field strength electrode of opposite sign. At 10 kV per cm the solutions conduct 3–7 times better when the highly charged electrode is positive in donor solutions. The opposite situation occurs in acceptor solutions. 相似文献
16.
B. Hlavőček J. Šestők L. Koudelka P. Mošner J. J. Mareš 《Journal of Thermal Analysis and Calorimetry》2005,80(2):271-283
Summary The forms of vibrations and displacements of particles in amorphous structures have been investigated. The particles, moving on highly non-linear amplitude, are responsible for the creation of disordered structures of amorphous bodies. The non-linear oscillators, even if 'few' in concentration, are characterized by unpredictable trajectories in phase space. The non-linear oscillators are fully developed in the liquid state above the crossover temperature Tcr and between Tcr and Tg their number decreases. Under Tg they completely disappear. The interconnection between the linear oscillators in blocks plays the most important role in the characteristic time spectra in liquid state. Using the additive properties of elements polarizibilities, the number of acoustical units in individual blocks at Tcr is estimated to be about 600 units. The diameter of blocks at Tcr was estimated to be about 1.8 nm. Even if the non-linear high amplitude motions disappear at solidification, the remnants of structural irregularity remain and the disordered structure of glass is formed. 相似文献
17.
Y.A DemchenkoA Razina Z SedlákovaA Sikora J BaldrianM Ilavský 《European Polymer Journal》2002,38(12):2333-2341
Thermotropic polyesters based on 4,4′-alkane-1-ω-diylbis(4-hydroxybenzoic acid) and 4,4′-(pentane-1,5-diyloxy)dibenzoic acid were studied by dynamic mechanical spectroscopy, X-ray scattering, differential scanning calorimetry and polarizing microscopy. The effect of structure changes in the mesogenic group as well as in the flexible spacer, in particular the incorporation of Cl atoms into the mesogen, introduction of ether oxygen into spacer and the number of CH2 groups in spacer was investigated. More complex mechanical and thermal behaviour was found on second heating scan than on first cooling of the isotropic melt; higher values of mechanical functions were observed in the isotropic state than in the nematic state of melts. While an even number of CH2 groups and the presence of ether oxygen in spacer shifts the transition temperatures to higher values, the incorporation of Cl atoms into the mesogen leads to disappearance of ordered structure and the polymers behave as amorphous materials. 相似文献
18.
Aranka Pilbáth Ilona Felhősi Gyula Tolnai Erika Kálmán 《Journal of Solid State Electrochemistry》2006,10(9):721-729
Due to the toxic and carcinogenic properties of hexavalent chromium ion, the corrosion protection with chromating technique needs replacement. Several environmentally friendly alternative metal pretreatments have already been proposed. One of these methods is the application of self-assembling molecules to form mono- or multilayers on the metal surfaces. These layers can prevent metal dissolution due to their dense and stable structure. The objective of our studies was to protect zinc surface against corrosion, with a thin phosphonate layer. Aqueous solutions of diphosphonic acid with different alkyl chain lengths were applied with different treatment times. The layer formation, stability, and corrosion protection of these films were monitored by electrochemical impedance spectroscopy and the effect of 1,5-diphosphono-pentane (DPP) on zinc was studied by polarization curves. The wetting properties were determined by static contact angle measurement. 1,5-Diphosphono-pentane forms a thin layer, with a pronounced protective ability in neutral aqueous solutions. The application of self-assembling molecules can be a promising method to replace the chromating technique on zinc surface. 相似文献
19.
星状四芳胺类空穴传输材料的合成 总被引:1,自引:0,他引:1
有机电致发光器件 (OELD)是继阴极射线管平板显示器 (CRT)和液晶显示器 (LCD)之后的第三代平板显示器。它具有主动发光、驱动电压低(2伏左右 )、发光亮度高 (1 3 0 0 0cd m2 以上 ) ,无软X 射线污染 ,响应速度快 (1 0 -6 ~ 1 0 -8秒 )等优点。从 1 987年美藉华人邓清云等提出多层结构的OELD的器件结构以来的十多年间 ,OELD以及其材料的研究已成为显示技术以及显示材料等方面的研究热点 ,发展很快[1~ 3] 。在 1 999年日本先锋公司已开发出了单色的汽车用OEL平板显示器商品 ,今年东芝公司又开发出了 2 .7英寸的彩… 相似文献
20.
High-temperature equilibrium calculations are used to study potential interferences in the determination of aluminium by flameless a.a.s. The conditions for the formation of interfering aluminium compounds like AlO(g), Al2O(g), Al2O3(s), AlOH(g), AlH(g), AlHO2(g), AlS(g), AlN(g), AlN(s) and AlCl(g) have been calculated. The influence of kinetic parameters on the equilibrium calculations for the reactions involving carbon—oxygen and carbon—sulphur has been established by varying the input amount of carbon. The results indicate that even in the nanomole range the presence of elements like H, O, N, Cl and S may cause severe interferences during the atomization step (2300–2900 K) 相似文献