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81.
目前步进电机以五相居多,硬件环形分配器用卡罗图来进行设计,则显得复杂冗赘,如果从步进电机运行的规律中找出约束条件,建立部分真值表,便可以直接写出控制逻辑函数,这对于设计相数、拍数较多的步进电机的环形分配器极为方便,这种设计思路在进行数字电路工程设计中也是可以值得借鉴的。 相似文献
82.
A new collectively fixed point theorem for a family of set-valued mappings defined on product spaces of non-compact topological spaces without linear structure is proved and some special cases are also discussed. As applications, some non-empty intersection theorems of sets with convex sections and equilibrium existence theorem of abstract economies are obtained under much weaker assumptions. Our results includes a number of known results as many special cases. 相似文献
83.
徐迅树 《华侨大学学报(自然科学版)》1991,12(2):249-263
提出科技期刊的表格,通用无线表和横线表的表式进行表达的理论和实践.论述了通用表表式的特点和要求,表头单、复式项目的设计,横视型和竖视型项目头的审改,不同栏数正、反线的合理应用,表身的恰当用线和疏密排.介绍了通用表的合并、转栏、分段、跨页的正确编排方法,以及特殊用表的变通方案.可供撰文、审校、编辑、排版工作借鉴. 相似文献
84.
Jeffrey N Brown 《Analytica chimica acta》2003,486(2):159-169
A new application of reversed-phase octadecyl (C18) solid phase extraction disks has been developed to separate the colloidally-associated polycyclic aromatic hydrocarbons (PAHs) from those that were truly dissolved in the samples of fresh water. A correction for the retention of small amounts of colloidal material on the C18 disks was required, which would have otherwise lead to minor underestimates in the degree of partitioning between the two phases. Using the humic substance Aldrich Humic Acid (AHA) as a model colloid and the 16 PAHs on the US Enrivonmental Protection Agency priority pollutant list, the partitioning coefficients of the PAHs between the colloidal and truly dissolved phases were shown to be proportional to the hydrophobicity of the PAHs, as measured by their octanol water partition coefficients (Kow). The values for the partition coefficients obtained (cKdoc′) were similar to those previously reported in the literature using alternative methods, confirming that the technique was producing acceptable results. The technique allows the in situ partitioning of PAHs between the truly dissolved and colloidal phases in fresh water bodies to be determined. It will provide an invaluable cross-check of the laboratory-based methods which often require substantial manipulation of the sample and potentially alter the partitioning between the phases. 相似文献
85.
一些新的序压缩映射的不动点定理 总被引:1,自引:1,他引:0
孙丽君 《郑州大学学报(理学版)》2007,39(1):24-28
在序Banach空间中,利用锥理论和单调迭代技巧对序压缩映射作了进一步的研究,对作用在序区间上的压缩映射给出了几个新的形式,并证明了相应的唯一不动点定理. 相似文献
86.
K. Popov-Pergal L. Cuckovic M. Rancic M. Pergal D. Djokovic 《Chemistry of Heterocyclic Compounds》2003,39(8):1090-1093
A series of methyl 2-(arylidene-2,4-dioxotetrahydrothiazol-3-yl)propionates were prepared. A study of the 3D structure was performed. The log P values are given for all the synthesized compounds. 相似文献
87.
We introduce a generalized notion of semiring and prove that all known properties that semirings have according to the old definition are preserved. 相似文献
88.
BinayakS.Choudhury 《分析论及其应用》2003,19(2):99-107
In the present paper we introduce a random iteration scheme for three random operators defined on a closed and convex subset of a uniformly convex Banach space and prove its convergence to a common fixed point of three random operators. The result is also an extersion of a known theorem in the corresponding non-random case. 相似文献
89.
Guido Consonni Piero Veronese Eduardo Gutirrez-Pea 《Journal of multivariate analysis》2004,88(2):335-364
Reference analysis is one of the most successful general methods to derive noninformative prior distributions. In practice, however, reference priors are often difficult to obtain. Recently developed theory for conditionally reducible natural exponential families identifies an attractive reparameterization which allows one, among other things, to construct an enriched conjugate prior. In this paper, under the assumption that the variance function is simple quadratic, the order-invariant group reference prior for the above parameter is found. Furthermore, group reference priors for the mean- and natural parameter of the families are obtained. A brief discussion of the frequentist coverage properties is also presented. The theory is illustrated for the multinomial and negative-multinomial family. Posterior computations are especially straightforward due to the fact that the resulting reference distributions belong to the corresponding enriched conjugate family. A substantive application of the theory relates to the construction of reference priors for the Bayesian analysis of two-way contingency tables with respect to two alternative parameterizations. 相似文献
90.
A set of invariants describing the limit regimes of braking disk-type wound composite flywheels is suggested. The limit regime is determined by using a linear failure criterion. It is shown that, for generating short-time impulses of very high power, a set of small identical flywheels is more effective than one large flywheel with an equivalent mass. Particular examples illustrating the theory considered are discussed. 相似文献