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991.
构造了S^1上S^3|H-丛的所有复结构的模空间,其中丛的转换函数u:s^3/H→S^3/H是S^3/H的一个对合,HU(2),H为有限群且在S^3/H上的作用是自由的。真不连续的。 相似文献
992.
Iwao Omae 《应用有机金属化学》2009,23(3):91-107
Group 9 metal compounds in organic synthesis have two characteristic reactions. The first occurs because the group 9 metals have a high affinity to carbon–carbon or carbon–nitrogen π‐bonds. The first type of characteristic reactions in these group 9 metal compounds includes Pauson–Khand reactions, the Pauson–Khand‐type reactions ([2 + 2 + 1] cyclization), the other cyclizations and coupling reactions. The second occurs because the group 9 metals have a high affinity to carbonyl groups. The second type of characteristic reactions includes carbonylations such as hydroformylations, the carbonylations of methanol, amidocarbonylations and other carbonylations. The first characteristic reactions are applied for the synthesis of fine chemicals such as pharmaceuticals and agrochemicals. However, the second characteristic reactions are utilized not only for fine chemicals but also for important bulk commodity chemicals such as aldehydes, carboxylic acids and alcohols. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
993.
We report the results of our modified distorted wave Born approximation calculation of triple differential cross section in the coplanar symmetric single ionization of potassium atom. We have included correlation-polarization potential as a function of electron density parameter and also studied the effect of post-collision interaction. The present attempt significantly improves the agreement between theoretical and experimental results. 相似文献
994.
995.
The values of the gas-chromatographic indicator reflecting the capacity of analytes for self-association in pure liquids,
δT
b.p., were estimated for C1–C9 and C11
n-alkanols by capillary gas chromatography on a nonpolar stationary phase under isothermal conditions. The δT
b.p. values ofn-alkanols, found as the difference between the boiling points measured directly and those calculated from GC data, are correlated
with thermodynamic characteristics of the formation ofn-alkanol associates in pure liquids. Usingn-alkanols as analytes with insignificant temperature increments of the retention indices, it was shown that the δT
b.p. values can be determined under conditions used in gas chromatography with temperature programming. In this way a single chromatographic
run can be used to compare the capacities for self-association of analytes boiling over a wide temperature range. The C2–C9
n-alkanethiols, which are not associated in neat liquids, have negative δT
b.p. values. An interpretation of this finding is proposed.
Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 315–318 February, 2000. 相似文献
996.
Chen-Bo Cai Qing-Juan Han Li-Juan Tang Lu Xu Jian-Hui Jiang Hai-Long Wu Ru-Qin Yu 《Adsorption》2009,15(1):23-29
Through non-invasive monitoring the uptake of aniline vapor by active alumina in a differential adsorption bed (DAB) with
near-infrared diffuse reflectance spectroscopy (NIR-DRS), we have studied several features of the adsorption, including isotherm,
kinetics and the chemical state of aniline molecules in aniline-alumina system. What is perhaps more important, since the
information above is obtained synchronously, the proposed methodology could provide information about the type of adsorption
(chemical or physical adsorption), the change of chemical state of aniline in the system during the adsorption process, whether
the chemical adsorption and physical adsorption took place simultaneously, the rate of the chemical and physical adsorption,
and so on. 相似文献
997.
An experimental investigation has been undertaken to improve understanding of the role of the obturator and detonations in
the subdetonative ram accelerator starting process. Ram accelerator start experiments were conducted with various obturator
geometries to determine the obturator dynamics and assess its effect on the outcome of a start attempt. The obturator rapidly
decelerates upon entrance and then moves backwards. Reversal of direction occurs more rapidly after propellant ignition, for
less massive obturators, and solid geometries. Perforated geometries and decreasing obturator mass are less conducive to igniting
a given propellant, as evidenced by the flowfield and start attempt outcome data presented. Wave unstarts were observed to
occur with and without detonations, indicating more than one mechanism responsible for this type of start failure. Piston-initiated
detonation experiments were conducted by firing the obturators without the ram accelerator projectile. The piston experiments
identified the detonation limits for a wide range of propellants, but were found to not always be indicative of the upper
Mach number at which a ram accelerator can be successfully started. In some instances a successful start or wave fall-off
would occur at Mach numbers above which a piston alone detonated the propellant. Thus, the projectile can play a mitigating
role in detonation initiation and use of piston detonation limits to quantitatively define a detonation wave unstart limit
was not realized.
Received 6 April 1998 / Accepted 15 January 1999 相似文献
998.
We consider a deteriorating system submitted to external and internal failures, whose deterioration level is known by means of inspections. There are two types of repairs: minimal and perfect, depending on the deterioration level, each one following a different phase-type distribution. The failures and the inspections follow different Markovian arrival processes (MAP). Under these assumptions, the system is governed by a generalized Markov process, whose state space and generator are constructed. This general model includes the phase-type renewal process as a special case. The distribution of the number of minimal and perfect repairs between two inspections are determined. A numerical application optimizing costs is performed, and different particular cases of the model are compared. 相似文献
999.
A classification theory of quantum stationary processes similar to the corresponding theory for classical stationary processes
is presented. Our main result is the classification of those pairs of classical stationary processes that admit a joint boson
Fock canonical representation.
Translated fromMatematicheskie Zametki, Vol. 67, No. 1, pp. 3–14, January, 2000. 相似文献
1000.
LiPing Huang 《中国科学A辑(英文版)》2009,52(11):2404-2418
Let D be a division ring with an involution-,H2(D) be the set of 2 × 2 Hermitian matrices over D. Let ad(A,B) = rank(A-B) be the arithmetic distance between A,B ∈ H2(D) . In this paper,the fundamental theorem of the geometry of 2 × 2 Hermitian matrices over D(char(D) = 2) is proved:if :H2(D) → H2(D) is the adjacency preserving bijective map,then is of the form (X) = tP XσP +(0) ,where P ∈ GL2(D) ,σ is a quasi-automorphism of D. The quasi-automorphism of D is studied,and further results are obtained. 相似文献