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91.
HOU JingMin 《中国科学:物理学 力学 天文学(英文版)》2010,(2)
The spectrum of cold fermionic atoms is studied in a trilayer honeycomb optical lattice subjected to a perpendicular effective magnetic field,which is created with optical means. In the low energy approximation,the spectrum shows unconventional Landau levels,which are proportional to the 3/2 power of integer numbers. The zoro modes exist and the quasiparticles are chiral. It is also proposed to identify the unconventional Landau levels via probing the dynamic structure factor of the system with Bragg spectr... 相似文献
92.
Daniela Bertacchi Giambattista Giacomin 《Bulletin of the Brazilian Mathematical Society》2003,34(3):401-415
We analyze a model of an interface fluctuating above a
rough substrate. It is based on harmonic crystals, or lattice
free fields, indexed by d ,
d 3. The phenomenon for
which we want to get precise quantitative estimates is the
repulsion effect of the substrate on the interface: the
substrate is itself a random field, but its randomness is
quenched (this generalizes
the widely considered case of a flat deterministic substrate).
With respect to [2] in which the substrate has been taken to be
an IID field, here the substrate is an harmonic crystal, as the
interface, and as such it is strongly correlated. We obtain the
leading asymptotic behavior of the model in the limit of a very
extended substrate: we show in particular that, to leading
order, the effect of an IID substrate cannot be distinguished
from the effect of an harmonic crystal substrate. We observe
however that, unlike in the IID substrate case, annealed and
quenched models display sharply different features. 相似文献
93.
《Arabian Journal of Chemistry》2022,15(12):104315
The green and high-value recycling of shrimp shell and straw remains a worldwide problem. This study aimed to investigate the potential utilization of a fermentation broth (FB) which contains shrimp shell and straw as a new source for preparation of biodegradable films. Aureobasidium pullulans and Photobacterium sp. LYM-1 were used in the fermentation. The cellulase activity was 115.92 U/mL and chitinase activity was 17.89 U/mL in FB. The polysaccharides concentration in FB was 1.05 mg/mL after 7 days of fermentation. An eco-friendly PVA-reinforced FB biodegradable film (FBBF) was successfully prepared and the effect of different plasticizers and surfactants on the mechanical, structural, and impermeability properties of the film was determined. The formation of new bonds between PVA and FB was proved by FTIR spectroscopy. The FBBF containing 0.25 % (w/v) glycerol and 0.01 % (v/v) tween-20 showed better strength properties. Elongation and water-swelling properties were highly improved by adding 0.2 % (m/v) citric acid. According to FE-SEM images, the smooth and tight surface of citric acid added FBBF was observed. Interestingly, the FBBF film showed good heat/moisture capacity, antifungal, and degradation properties. This report reveals a new green, and high-value recycling of straw and shrimp shell by the co-fermentation with A. pullulans and Photobacterium sp. LYM-1. It is also a novel way for the preparation of biodegradable film. 相似文献
94.
Francisco López-Linares Alberto Fuentes Rita Tenia Maria Martinez Arquímedes Karam 《Reaction Kinetics and Catalysis Letters》2007,92(2):285-292
This work describes the homogeneous hydrogenation of different α,β-unsaturated substrates by using as catalyst systems the
complex [Ir(COE)2Cl]2 stabilized by tris(2-pyridyl)amine (tpN) or tris(2-pyridyl)phosphine (tpP) formed in situ under the following reaction conditions:
pH2 = 34 atm; T=373 K; substrate/catalyst ratio = 100, [ligand]/[metal]: 2,1; toluene (50 mL); R.P.M.: 430; t = 6 h. The activities
varies from low to moderate range, where both ligands proved to be catalyst systems able to hydrogenate C=C and C=O bonds. 相似文献
95.
Methodi Chetkarov Lachezar Karagyozov Todor Nikolov Dimiter Kolev 《Monatshefte für Chemie / Chemical Monthly》1986,117(8-9):1021-1026
The reaction cellulase (EC 3.2.1.4)—sodium carboxymethylcellulose (Na-CMC) with different degrees of polymerization (n=140, 640 and 900) was investigated by the use of a modifiedMichaelis-Menten equation, valid for enzymatic hydrolysis of linear homopolymers. TheMichaelis-Menten constant [Km (M)=6.31·10–2mol/dm3] and the reaction rate constant (k
+2=4.07·10–6s–1), which correspond to the enzymatic hydrolysis of a single bond in the homopolymer substrates are determined. The free energy (
=101 kJ/mol), which corresponds to the degradation and formation of a single bond in the enzyme—polymer substrate is also estimated. This energy expressed in electronvolt units is
=1.39 eV. The ratio between the effective cross section of the reactive substrate bond and the active enzyme center is =1.22.
Kinetik der enzymkatalysierten Hydrolyse von Natriumcarboxymethylcellulose mit verschiedenem Polymerisationsgrad durch Cellulase
Zusammenfassung Die modifizierte Gleichung nachMichaelis-Menten wird bei der durch Cellulase (EC 3.2.1.4) katalysierten hydrolytischen Spaltung von Natriumcarboxy-methylcellulose (Na-CMC) verschiedenen Polymerisationsgrades (n=140, 640 und 900) angewandt. Es wurde dieMichaelis-Menten-Konstante [Km (M)=6.31·10–2mol/dm3] und die Reaktionsgeschwindigkeitskonstante (k +2=4.07·10–6s–1), die der enzymatischen Hydrolyse einer Einfachbindung im homopolymeren Substrat entspricht, berechnet. Die freie Energie ( =101 kJ/mol), die dem Abbau und der Bildung einer Einfachbindung im Enzym—Polymer-Substrat entspricht, wurde bestimmt. Diese Energie — ausgedrückt in Elektronvolt-Einheiten — beträgt =1.39 eV. Das Verhältnis zwischen den effektiven Querschnitten der reaktiven Substratbindung ( S ) und des aktiven Enzym-Zentrums ( E ) beträgt =1.22.相似文献
96.
L. Yu Y. Krockenberger Ingo Fritsch H.-U. Habermeier 《Progress in Solid State Chemistry》2007,35(2-4):545-551
NaxCoO2 [x = 0.51, 0.54, and 0.59] thin films have been grown on SrTiO3 (100)-oriented single crystals with a 5° vicinal cut towards [010] by pulsed laser deposition. We analysed the films by X-ray diffractometry, atomic force microscopy (AFM), and dc-transport measurements. X-ray diffraction patterns of the films show single phase and c-axis textured growth with the film plane closely aligned to the [001]-direction of 5° miscut SrTiO3 (001) substrates. In addition to the structural analysis of these films we performed transport measurements along and perpendicular to the substrate tilt direction and determined the resistivity anisotropy as a function of temperature. The results enable the development of a strategy for the fabrication of NaxCoO2 based thermoelectric thin film devices. 相似文献
97.
Y. Bogumilowicz J.M. Hartmann C. Di Nardo P. Holliger A.-M. Papon G. Rolland T. Billon 《Journal of Crystal Growth》2006,290(2):523-531
We have first of all studied (in reduced pressure–chemical vapour deposition) the high-temperature growth kinetics of SiGe in the 0–100% Ge concentration range. We have then grown very high Ge content (55–100%) SiGe virtual substrates at 850 °C. We have focused on the impact of the final Ge concentration on the SiGe virtual substrates’ structural properties. Polished Si0.5Ge0.5 virtual substrates were used as templates for the growth of the high Ge concentration part of such stacks, in order to minimize the severe surface roughening occurring when ramping up the Ge concentration. The macroscopic degree of strain relaxation increases from 99% up to values close to 104% as the Ge concentration of our SiGe virtual substrates increases from 50% up to 100% (discrepancies in-between the thermal expansion coefficients of Si and SiGe). The surface root mean square roughness increases when the Ge concentration increases, reaching values close to 20 nm for 100% of Ge. Finally, the field (the pile-up) threading dislocations density (TDD) decreases as the Ge concentration increases, from 4×105 cm−2 (1–2×105 cm−2) for [Ge]=50% down to slightly more than 1×105 cm−2 (a few 104 cm−2) for [Ge]=88%. For [Ge]=100%, the field TDD is of the order of 3×106 cm−2, however. 相似文献
98.
以一个广义协调元为例证明了非常规有限元与其常规对偶有限元刚度矩阵的谱等价性。该结果对非常规有限元的区域分解并行算法研究有重要作用。 相似文献
99.
Heinz Kohler 《Applied biochemistry and biotechnology》2000,83(1-3):1-12
The antibody molecule possesses a number of so-called unconventional binding sites in the variable domain that are expressed
and function independently from the antigen-binding site. These sites are encoded in the germiline, predominantly in framework
residues. By this definition, these sites function as part of the innate immunity, and are not subject to antigendriven mutation
and maturation. In this article, we focus on the evidence for the function and utility of the self-binding domain. The self-binding
or autophilic domain has been discovered on murine germline-encoded antibodies from the S107/T15 Vh family. Autophilic antibodies
form self-complexes after attaching to targets, but remain monomeric in solution. A peptide has been identified that confers
self-binding if chemically attached to antibodies. Because this modification enhances the overall avidity of antibodies for
target binding, therapeutic and diagnostic antibodies can be biotechnologically improved.
The concept of super antibodies is introduced here to describe the unique coexistence and synergism of acquired immunity with
innate immunity via antigen-specific and unconventional functional domains. As not every antibody qualifies as a super antibody,
biotechnology engineering can produce superantibodies with superior targeting and therapeutic properties. 相似文献
100.