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51.
本文通过对螺旋桨升力面的涡系模型的理论分析,引用模式函数及变密度自由涡 索的概念建立了模式自由涡密度的计算模型,并导出了与其相应的全部模式涡系的分 布密度及诱导速度公式。这样,就完满地解决了由于采用 Birnbaum级数而带来的 奇点积分问题,并大大地简化了计算. 相似文献
52.
朱计生 《系统工程理论与实践》1992,12(5):0-0
<正> 一、引言 在制订年度农业生产计划时,耕地如何在各种作物之间进行分配是一个十分重要的问题。由于未来一年内气候及其它因素的不确定性,各种农作物的单位产量是不确定的。设农作物单产的不确定性可以用某种随机分布来刻划,这时耕地分配就成了一个风险决策问题。随机优势方 相似文献
53.
Derivations of fractal models of city hierarchies using entropy-maximization principle 总被引:1,自引:0,他引:1
A pair of models of fractal recursion on city hierarchy, fm=f1r?1-m?f and Pm=P1r?m-1?p, are derived using entropy-maximizing methods, and the relationship of inverse proportion between the number (fm) of cities at a given level of the urban hierarchy and the average population size (Pm) of the fm cities is established, i.e fm∝1/P. It is demonstrated that the underlying rationale of both the scale law of city rank-size distribution and the Zipf dimension value in standard state (dz=lnrp/lnrf=1) rests with maximization of information entropy of city hierarchies. 相似文献
54.
分析了高校党外知识分子思想政治工作的现状,从高校民主党派组织生活不够完善、党派意识不够、党外知识分子具有的新特点及各级人大、代表等的换届工作需要等方面论述了加强高校党外知识分子思想政治工作的必要性,并从掌握党外知识分子思想动态、编制党外知识分子思想政治工作规划、推出党外知识分子思想政治工作举措以及完善制度机制等方面阐述对加强高校党外知识分子思想政治工作进行思考。 相似文献
55.
XU Liang XU Jisheng Koustov Alexandre Papitashvili Vladimir Rich Fedrich 《武汉大学学报:自然科学英文版》2007,12(2):279-283
Recently several studies indicated possible deterioration of accuracy in the SuperDARN convection measurements at large distances (〉2 500 km). In this study, the SuperDARN-derived convection was compared with ion drift measurements given by the DMSP satellites, focused on SuperDARN far-range measurements, to investigate the above-mentioned problem. Two different procedures of SuperDARN convection estimation were applied. An overall reasonable agreement between two observation systems were found though individual points in some passes show significant differences. Besides, a tendency is also clear that the SuperDARN-derived velocities were slightly smaller than those of DMSP ion drift measurements. Potential factors contributing to the velocity differences were explained. 相似文献
56.
1Introduction Satelliteisacomplexsystemandconsistsofmany componentstobeusedfordifferentfunctions.Satellitewill beinfailureifsomecomponentsdegradeorfail.Thefailure affectsthenormalapplicationofthesatelliteseverely[1].The goaloftheresearchinthispaperistodeduceoravoidthe affectionsandlossescausedbysatellitefailure,inorderthat thesatellitecanremainavailablewhensomecomponentson satelliteareatdegradationorinfailure.ProfessorDudaPearlproposedBayesiannetworktheoryin1988.Themethodofsatellitefaultdiag… 相似文献
57.
在文〔1〕基础上,将普通集合方程推广到有限集合上的Fuzzy集方程和方程组,并讨论了Fuzzy关系方程. 相似文献
58.
本文指出了广泛流行的一些书中关于单纯形法的一个逻辑错误,分析了错误产生的原因,并指出了求解的正确途径。 相似文献
59.
McDermott-Roe C Ye J Ahmed R Sun XM Serafín A Ware J Bottolo L Muckett P Cañas X Zhang J Rowe GC Buchan R Lu H Braithwaite A Mancini M Hauton D Martí R García-Arumí E Hubner N Jacob H Serikawa T Zidek V Papousek F Kolar F Cardona M Ruiz-Meana M García-Dorado D Comella JX Felkin LE Barton PJ Arany Z Pravenec M Petretto E Sanchis D Cook SA 《Nature》2011,478(7367):114-118
Left ventricular mass (LVM) is a highly heritable trait and an independent risk factor for all-cause mortality. So far, genome-wide association studies have not identified the genetic factors that underlie LVM variation, and the regulatory mechanisms for blood-pressure-independent cardiac hypertrophy remain poorly understood. Unbiased systems genetics approaches in the rat now provide a powerful complementary tool to genome-wide association studies, and we applied integrative genomics to dissect a highly replicated, blood-pressure-independent LVM locus on rat chromosome 3p. Here we identified endonuclease G (Endog), which previously was implicated in apoptosis but not hypertrophy, as the gene at the locus, and we found a loss-of-function mutation in Endog that is associated with increased LVM and impaired cardiac function. Inhibition of Endog in cultured cardiomyocytes resulted in an increase in cell size and hypertrophic biomarkers in the absence of pro-hypertrophic stimulation. Genome-wide network analysis unexpectedly implicated ENDOG in fundamental mitochondrial processes that are unrelated to apoptosis. We showed direct regulation of ENDOG by ERR-α and PGC1α (which are master regulators of mitochondrial and cardiac function), interaction of ENDOG with the mitochondrial genome and ENDOG-mediated regulation of mitochondrial mass. At baseline, the Endog-deleted mouse heart had depleted mitochondria, mitochondrial dysfunction and elevated levels of reactive oxygen species, which were associated with enlarged and steatotic cardiomyocytes. Our study has further established the link between mitochondrial dysfunction, reactive oxygen species and heart disease and has uncovered a role for Endog in maladaptive cardiac hypertrophy. 相似文献
60.
This paper gives a new iterative method to solve the non-linear equation. We prove that this method has the asymptotic convergent order. When the iterative times exceed 2,only one evaluation of the function and one of its first derivative is required by each iteration of the method.Therefore the new method is better than Newton’s method. 相似文献