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1.
2.
本文运用信息保存法对低速二维的流动现象进行模拟,考察了低速条件下的有限平板绕流以及微槽道气体流动问题。研究表明:在对低速流动的模拟过程中,运用IP法在能够获得较好的结果的同时,具有比DSMC方法更高的计算效率。 相似文献
3.
In the present paper, we prove that the Bernstein-Kantorovič operators have the ability of preserving translation property
in both C and Lp norms.
Supported (in part) by the NSFC(10471130,10371024) of PRC and the Natural Science Foundation (Y604003) of Zhejiang Province. 相似文献
4.
WU Xiu-Lan WANG Fen REN Qiang 《结构化学》2007,26(6):732-736
Homogeneous cordierite has been synthesized at low cost by talc-magnesite and coal gangue as the main raw materials. The mechanism of synthesizing cordierite under such a com- posing system of raw materials, and the effect of temperature on the crystal cell parameters and microstructure and thermal expansion coefficient of cordierite crystal have been studied via testing methods of XRD, SEM, etc. The result shows that the homogeneous cordierite can be synthesized by the systematic composing materials of “talc-magnesite—coal gangue—talc” with heat pre- servation at 1350 ℃ for 1 h; as the keeping time is prolonged, Al3+ and Mg2+ in cordierite crystal are replaced by a few impurity ions such as Fe3+, Fe2+, etc., and the crystal cell parameters of cordierite present an increase trend; as the high-temperature heat preservation is prolonged, the content of glassy phase in the sample is increased, its density is improved, and its thermal expansion coeffi- cient presents an increase trend. 相似文献
5.
The applicability of the epr technique for the detection of dried vegetables, mushrooms, some spices, flavour additives and some condiments preserved with ionizing radiation is discussed. The epr signals recorded after exposure to gamma rays and to beams of 10 MeV electrons from linac are stable, intense and specific enough as compared with those observed with nonirradiated samples and could be used for the detection of irradiation. However, stability of radiation induced epr signals produced in these foods depends on storage condition.
No differences in shapes (spectral parameters) and intensities of the epr spectra recorded with samples exposed to the same doses of gamma rays (60Co) and 10 MeV electrons were observed 相似文献
6.
H. R. Schulten Si-En Sun 《International journal of environmental analytical chemistry》2013,93(3-4):247-263
The characteristic behaviour of four groups of commonly used organophosphorus pesticides such as phosphates, phosphorothionates, phosphorothiolates and phosphorodithioates has been investigated by field desorption mass spectrometry. Their spectra show molecular ions of high abundance and characteristic fragmentation patterns. The phosphates and phosphorothionates usually show the α-cleavage with respect to the P-atom with and without proton transfer. In contrast, the phosphorothiolates and phosphorodithioates usually show the β-cleavage from the P-atom. The fragments with the charge retention on the phosphorus moiety were also observed in the field desorption mass spectra, although their abundances were often relatively low. The analyses of standard mixtures as well as some waste water samples indicate that field desorption mass spectrometry is suitable for the identification of organophosphorus pesticides at nanogram level in mixtures and environmental samples without preliminary separation and purification. 相似文献
7.
F. Weekers Ph. Jacques D. Springael M. Mergeay L. Diels Ph. Thonart 《Applied biochemistry and biotechnology》1999,77(1-3):251-266
Bacterial strains were selected from a desiccated polluted soil for their drought tolerance and their ability to grow on diesel
oil in view of incorporating them in a bioaugmentation product. These products are useful in case of recal citrant xenobiotic
pollution, where there is no intrinsic biodegradation activity in the soil. These strains grow on the easily degradable components
of diesel oil. In troduction of new catabolic genes into these desiccation-tolerant bacteria in order to improve their catabolic
functions was considered.
Plasmid-borne catabolic genes coding for enzymes in volved in the degradation of more recalcitrant compounds (Isopropylbenzene,
trichloroethene, 3-chloroben zoate, 4-chlorobiphenyl, biphenyl) were successfully introduced in some of the desiccation-tolerant
strains by means of natural conjugation. Strains exhibiting good tolerance to desiccation and able to grow on the new carbon
sources were obtained. The frequencies of integration of the plasmids ranged from 2×10−8 to 9.2 10−2 transconjugants/acceptor.
Drought-tolerance is indeed important for bioaugmentation because of its in trinsic ecological significance and because a
bioaugmentation starter has to be conditioned in a desic cated form to ensure good shelf-life. The conservation of the properties
during storage was evaluated by accelerated storage tests. 相似文献
8.
The paper describes a new space of variable degree polynomials. This space is isomorphic to ℙ6, possesses a Bernstein like basis and has generalized tension properties in the sense that, for limit values of the degrees,
its functions approximate quadratic polynomials. The corresponding space of C
3, variable degree splines is also studied. This spline space can be profitably used in the construction of shape preserving
curves or surfaces.
AMS subject classification (2000) 65D07, 65D17, 65D10 相似文献
9.
R. I. McLachlan H. Z. Munthe-Kaas G. R. W. Quispel A. Zanna 《Foundations of Computational Mathematics》2008,8(3):335-355
We present new explicit volume-preserving methods based on splitting for polynomial divergence-free vector fields. The methods
can be divided in two classes: methods that distinguish between the diagonal part and the off-diagonal part and methods that
do not. For the methods in the first class it is possible to combine different treatments of the diagonal and off-diagonal
parts, giving rise to a number of possible combinations.
This paper is dedicated to Arieh Iserles on the occasion of his 60th anniversary. 相似文献
10.