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991.
Dimethylmaleoyl (DMM) moiety has become an important amine protective group in sugar chemistry. We disclose herein that DMM-containing
D-glucosamine analogues, because of their electrophilic nature, are prone to reactions with strong nucleophiles, such as hydrazine,
resulting in a set of undesired side products that are difficult to detect, yet proved to be problematic for organic synthesis. 相似文献
992.
N. Pitsianis Ph. Tsalides G. L. Bleris A. Thanailakis H. C. Card 《Journal of statistical physics》1989,56(1-2):99-112
A formal treatment of some of the properties of deterministic, rule 150, elementary one-dimensional cellular automata (CA) with null boundary conditions is presented. The general form of the characteristic polynomial of the CA global rule transition matrix is obtained. Mathematical relationships between the CA register lengths and the order of the corresponding group or semigroup structures are derived. 相似文献
993.
A novel polymer-bound 1,2-diol, 3-polystyrylsulfonyl-1,2-propanediol (6) had been prepared by the reaction of sodium polystyrylsulfinate with allyl bromide, followed by oxidation and. hydrolysis or directly with 3-chloro-1,2-propanediol in the presence of a phase transfer catalyst, n-tetrabutylammonium iodide. The capacity of resin 6 for terephthaidehyde reached 1.43 mmol/g. The aldehydic groups attached to polymer 6 reacted with hydroxylamine hydrochloride or reduced by sodium borohydride giving p-formylbenzaldoxime (yield: 89%)and p-formyl-benzalcohol (yield: 734%), respectively. The high yields of these polymer-supported reactions showed that the polymer 6 possessed the effective isolation of its reactive sites. 相似文献
994.
Queueing theorists have presented, as solutions to many queueing models, probability generating functions in which state probabilities are expressed as functions of the roots of characteristic equations, evaluation of the roots in particular cases being left to the reader. Many users have complained that such solutions are inadequate. Some queueing theorists, in particular Neuts [6], rather than use Rouché's theorem to count roots and an equation-solver to find them, have developed new algorithms to solve queueing problems numerically, without explicit calculation of roots. Powell [7] has shown that in many bulk service queues arising in transportation models, characteristic equations can be solved and state probabilities can be found without serious difficulty, even when the number of roots to be found is large. We have slightly modified Powell's method, and have extended his work to cover a number of bulk-service queues discussed by Chaudhry et al. [1] and a number of bulk-arrival queues discussed in the present paper. 相似文献
995.
The dynamic Monte Carlo Renormalization group method introduced by Jan, Moseley, and Stauffer is used to determine the dynamic exponent of the Ising model with conserved magnetization in two dimensions. We present an explicit theoretical basis for the method and expand on the original results for the Kawasaki model. The new result clearly demonstrates the validity of the method and the value of the dynamic exponent,z=3.79±0.05, supports the conclusion of Halperin, Hohenberg, and Ma. 相似文献
996.
两类重要p-群及其自同构群的阶 总被引:1,自引:0,他引:1
In the paper we obtain two infinite classes of p-groups,calculate the orders of their automorphism groups and correct a mistake(perhaps misprinted)of Rodney James'paper in 1980. 相似文献
997.
Representations of distributive semilattices in ideal lattices of various algebraic structures 总被引:2,自引:0,他引:2
We study the relationships among existing results about representations of distributive semilattices by ideals in dimension
groups, von Neumann regular rings, C*-algebras, and complemented modular lattices. We prove additional representation results
which exhibit further connections with the scattered literature on these different topics.
Received March 2, 1998; accepted in final form November 9, 2000. 相似文献
998.
令t(G)为有限阿贝尔群G的单因子个数.本文得到了∑|G|≤xt(G)带有更好余项的渐近公式. 相似文献
999.
Taen-Yu Dai 《Algebra Universalis》2001,45(4):407-424
No abstract.
Received September 2, 1999; accepted in final form October 23, 2000. 相似文献
1000.