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本论文通过CT总公司所属九个分公司财务指标即:财务效益状况指标,资产营运状况指标,偿债能力状况指标,发展能力状况指标和稳固程度状况指标五个方面的财务状况数据,一方面采用数理统计方法进行数据分析,建立数学模型,设定了评分办法及评分标准.做出了CT总公司所属九个分公司2 0 0 0年的经营业绩(量化)评价结果.另一方面按九个公司财务指标的原始数据用聚类分析的方法将其归类,进一步揭示出各个公司之间的联系与差别. 相似文献
996.
Flow past a circular cylinder for Re=100 to 107 is studied numerically by solving the unsteady incompressible two‐dimensional Navier–Stokes equations via a stabilized finite element formulation. It is well known that beyond Re ~ 200 the flow develops significant three‐dimensional features. Therefore, two‐dimensional computations are expected to fall well short of predicting the flow accurately at high Re. It is fairly well accepted that the shear layer instability is primarily a two‐dimensional phenomenon. The frequency of the shear layer vortices, from the present computations, agree quite well with the Re0.67 variation observed by other researchers from experimental measurements. The main objective of this paper is to investigate a possible relationship between the drag crisis (sudden loss of drag at Re ~ 2 × 105) and the instability of the separated shear layer. As Re is increased the transition point of shear layer, beyond which it is unstable, moves upstream. At the critical Reynolds number the transition point is located very close to the point of flow separation. As a result, the shear layer eddies cause mixing of the flow in the boundary layer. This energizes the boundary layer and leads to its reattachment. The delay in flow separation is associated with narrowing of wake, increase in Reynolds shear stress near the shoulder of the cylinder and a significant reduction in the drag and base suction coefficients. The spatial and temporal power spectra for the kinetic energy of the Re=106 flow are computed. As in two‐dimensional isotropic turbulence, E(k) varies as k?5/3 for wavenumbers higher than energy injection scale and as k?3 for lower wavenumbers. The present computations suggest that the shear layer vortices play a major role in the transition of boundary layer from laminar to turbulent state. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
997.
The shear-induced isotropic-to-nematic phase transition of side chain liquid-crystalline polymers is studied theoretically. A modification of the previous models of main-chain liquid crystals to the case of side chain liquid-crystalline polymers is proposed. Orientational and rheological properties of the model are studied in plane-shear flow. Predictions of the present model agree qualitatively with experimental results (Pujolle-Robic, Noirez in Nature 409:167, 2001). 相似文献
998.
Yongqi Wang Tasawar Hayat Abdul Majeed Siddiqui 《Mathematical Methods in the Applied Sciences》2005,28(3):329-347
The present investigation deals with an undulating surface model for the motility of bacteria gliding on a layer of non‐Newtonian slime. The slime being the viscoelastic material is considered as a power‐law fluid. A hydrodynamical model of motility involving an undulating cell surface which transmits stresses through a layer of exuded slime to the substratum is examined. The non‐linear differential equation resulting from the balance of momentum and mass is solved numerically by a finite difference method with an iteration technique. The manner in which the various exponent values of the power‐law flow affect the structure of the boundary layer is delineated. A comparison is made of the power‐law fluid with the Newtonian fluid. For the power‐law fluid with respect to different power‐law exponent values, shear‐thinning and shear‐thickening effects can be observed, respectively. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
999.
Zhi Hui Zhou Jian Hua Yang* Li Feng Chang Yan Zhang Wei Guo Sun Jin Qu Wang* State Key Laboratory of Fine Chemicals Institute of Adsorption Inorganic Membrane Dalian University of Technology Dalian PR China 《中国化学快报》2007,18(4):455-457
Novel NaA/carbon nanocomposite thin films were successfully prepared on a porous a-Al2O3 substrate by incorporatingnanosized NaA zeolite into novolak-type phenolic resin.The prepared films were characterized by XRD,SEM and single gaspermeation tests.The NaA zeolite/carbon nanocomposite thin films exhibited that the ideal separation factor of CO2/CH4 was 28.4and the carbon dioxide flux was 3.39*10-7mol/(Pa m2s)at room temperature and under a pressure difference of 100 kPa,whichwas two orders of magnitude higher than that of pure carbon membrane prepared at the same procedures and conditions as those ofcomposite films.From the SEM images,the films were continuous and highly intergrown.Compared with carbon membranes,thethickness of nanocomposite films was drastically decreased,which was helpful to reduce the diffusion resistance and increase theflux of gas permeance. 相似文献
1000.
Walid F. Nasrallah 《Computational & Mathematical Organization Theory》2006,12(4):339-359
Interaction Value Interaction Value Analysis (I.V.A.) models a network of rational actors who generate value by interacting
with each other. This model can be used to understand human organizations. Since people form organizations to facilitate interactions
between productive individuals, the value added by interaction is the contribution of the organization. This paper examines
the result of varying the queuing discipline used in selecting among back-logged interaction requests. Previously developed
I.V.A. models assumed a First-in-first-out (FIFO) discipline, but using other disciplines can better represent the “Climate”
of an organization.
I.V.A. identifies circumstances under which organizations that control members’ interaction choices outperform organizations
where individuals choose their own interaction partners. Management can be said to “matter” when individual choices converge
to a point where interactions generate a lower than optimal value. In previous I.V.A. models, relinquishing central control
of interaction choices reduced the aggregate value by anything from 0% to 12%, depending on circumstances. This paper finds
the difference between the two modes of organization to go as high as 47% if actors display preferences between interaction
partners instead of treating all equally. A politically divided, dog-eat-dog, “Capitalist” climate follows one queuing discipline,
which is found to generally increase the value that a strong control structure can add. A chummy, in-bred “Fraternal” climate
gains from control in some circumstances (low interdependence or low differentiation), but not in others (high or medium interdependence
and differentiation under low diversity, for example). These are compared to the previous version of I.V.A., in which the
queuing discipline was FIFO and the climate deemed “Disciplined”. Previously published findings on Organizational Climate
are duplicated and extended with a higher level of detail. Priority queuing in an I.V.A. model is thus a useful proxy for
Organizational Climate, open to future validation because its detailed predictions can be confirmed or falsified by observation.
Walid Nasrallah is currently Assistant Professor in the Engineering Management program at the American University of Beirut (AUB). He received
his Ph.D. from the Construction Engineering and Management program at Stanford University in 2000 and his Master’s degree
at MIT in 1989. Between the two, he occupied several positions in the construction and software engineering fields. His research
interests today include simulation, decision theory, and the evolution of organizations in response to new technologies. 相似文献