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排序方式: 共有93条查询结果,搜索用时 306 毫秒
1.
2.
We propose a parametric tensioned version of the FVS macro-element to control the shape of the composite surface and remove artificial oscillations, bumps and other undesired behaviour. In particular, this approach is applied to C1 cubic spline surfaces over a four-directional mesh produced by two-stage scattered data fitting methods. 相似文献
3.
Laila Manni Olfa Ghorbel-Bellaaj Kemel Jellouli Islem Younes Moncef Nasri 《Applied biochemistry and biotechnology》2010,162(2):345-357
Chitin is a polysaccharide found in abundance in the shell of crustaceans. In this study, the protease from Bacillus cereus SV1 was applied for chitin extraction from shrimp waste material of Metapenaeus monoceros. A high level of deproteinization 88.8% ± 0.4 was recorded with an E/S ratio of 20. The demineralization was completely achieved
within 6 h at room temperature in HCl 1.25 M, and the residual content of calcium in chitin was below 0.01%. 13C CP/MAS-NMR spectral analysis of chitin prepared by the enzymatic deproteinization of shrimp wastes was found to be similar
to that obtained by alkaline treatment and to the commercial α-chitin. The degree of N-acetylation, calculated from the spectrum,
was 89.5%. Chitin obtained by treatment with crude protease from B. cereus was converted to chitosan by N-deacetylation, and the antibacterial activity of chitosan solution against different bacteria
was investigated. Results showed that chitosan solution at 50 mg/mL markedly inhibited the growth of most Gram-negative and
Gram-positive bacteria tested. Furthermore, the antioxidant potential of the protein hydrolysates obtained during enzymatic
isolation of chitin was evaluated using various in vitro assays. All the samples exerted remarkable antioxidant activities. These results suggest that enzymatic deproteinization
of the shrimp shell wastes, using B. cereus SV1 protease, could be applicable to the chitin production process. 相似文献
4.
Lagoudakis KG Manni F Pietka B Wouters M Liew TC Savona V Kavokin AV André R Deveaud-Plédran B 《Physical review letters》2011,106(11):115301
The experimental investigation of spontaneously created vortices is of utmost importance for the understanding of quantum phase transitions towards a superfluid phase, especially for two-dimensional systems that are expected to be governed by the Berezinski-Kosterlitz-Thouless physics. By means of time-resolved near-field interferometry we track the path of such vortices, created at random locations in an exciton-polariton condensate under pulsed nonresonant excitation, to their final pinning positions imposed by the stationary disorder. We formulate a theoretical model that successfully reproduces the experimental observations. 相似文献
5.
Manni F Lagoudakis KG Liew TC André R Deveaud-Plédran B 《Physical review letters》2011,107(10):106401
Exciton-polariton condensation can be regarded as a self-organization phenomenon, where phase ordering is established among particles in the system. In such condensed systems, further ordering can occur in the particle density distribution, under particular experimental conditions. In this work we report on spontaneous pattern formation in a polariton condensate under nonresonant optical pumping. The slightly elliptical ring-shaped excitation laser that we employ forces condensation to occur into a single-energy state with periodic boundary conditions, giving rise to a multilobe standing-wave patterned state. 相似文献
6.
Manni F Lagoudakis KG Pietka B Fontanesi L Wouters M Savona V André R Deveaud-Plédran B 《Physical review letters》2011,106(17):176401
We study the coherence and density modulation of a nonequilibrium exciton-polariton condensate in a one-dimensional valley with disorder. By means of interferometric measurements we evidence a modulation of the first-order coherence function and we relate it to a disorder-induced modulation of the condensate density, that increases as the pump power is increased. The nonmonotonic spatial coherence function is found to be the result of the strong nonequilibrium character of the one-dimensional system, in the presence of disorder. 相似文献
7.
Carlo Garoni Carla Manni Francesca Pelosi Stefano Serra-Capizzano Hendrik Speleers 《Numerische Mathematik》2014,127(4):751-799
We study the spectral properties of stiffness matrices that arise in the context of isogeometric analysis for the numerical solution of classical second order elliptic problems. Motivated by the applicative interest in the fast solution of the related linear systems, we are looking for a spectral characterization of the involved matrices. In particular, we investigate non-singularity, conditioning (extremal behavior), spectral distribution in the Weyl sense, as well as clustering of the eigenvalues to a certain (compact) subset of \(\mathbb C\) . All the analysis is related to the notion of symbol in the Toeplitz setting and is carried out both for the cases of 1D and 2D problems. 相似文献
8.
9.
In this paper we address the problem of constructing quasi-interpolants in the space of quadratic Powell-Sabin splines on
nonuniform triangulations. Quasi-interpolants of optimal approximation order are proposed and numerical tests are presented.
Dedicated to Prof. Mariano Gasca on the occasion of his 60th birthday. 相似文献
10.
Phase Behavior of a Designed Cyclopropyl Analogue of Monoolein: Implications for Low‐Temperature Membrane Protein Crystallization 下载免费PDF全文
Livia Salvati Manni Dr. Alexandru Zabara Dr. Yazmin M. Osornio Jendrik Schöppe Dr. Alexander Batyuk Prof. Dr. Andreas Plückthun Prof. Dr. Jay S. Siegel Prof. Dr. Raffaele Mezzenga Prof. Dr. Ehud M. Landau 《Angewandte Chemie (International ed. in English)》2015,54(3):1027-1031
Lipidic cubic phases (LCPs) are used in areas ranging from membrane biology to biodevices. Because some membrane proteins are notoriously unstable at room temperature, and available LCPs undergo transformation to lamellar phases at low temperatures, development of stable low‐temperature LCPs for biophysical studies of membrane proteins is called for. Monodihydrosterculin (MDS) is a designer lipid based on monoolein (MO) with a configurationally restricted cyclopropyl ring replacing the olefin. Small‐angle X‐ray scattering (SAXS) analyses revealed a phase diagram for MDS lacking the high‐temperature, highly curved reverse hexagonal phase typical for MO, and extending the cubic phase boundary to lower temperature, thereby establishing the relationship between lipid molecular structure and mesophase behavior. The use of MDS as a new material for LCP‐based membrane protein crystallization at low temperature was demonstrated by crystallizing bacteriorhodopsin at 20 °C as well as 4 °C. 相似文献