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在对笔算和珠算进行对比分析以前,我们首先要搞清楚一些基本概念和基本知识,否则就会出现不知所云和莫名其妙的情况。进行对比分析就要求二者处在同一起跑线上,否则就没有可比性。
一、几个基本概念
(一)教学的定义 相似文献
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目前PPP模式的应用范围不断扩大,但投资者的融资效率普遍不高。投资者融资效率低下严重影响PPP项目绩效,制约PPP模式的可持续发展。本文以51家主营业务为PPP项目的国有企业与民营企业为样本,运用DEA模型分别从整体、不同领域和不同地区之间对比分析双方融资效率的异同。结果显示参与PPP项目投资者的规模效率普遍不足,主营成本与股权集中度是导致融资效率低下的主要因素,净资产收益率较低则是投资者不愿积极参与PPP项目的一个主要原因。对国企而言,优化企业对PPP项目的规模效率是提高融资效率的关键;而民企应注重优化和降低资产负债率,合理均衡地分配股权。因此,建议具有规模效率和纯技术效率优势的投资者通过组建联合体等方式参与PPP项目,实现优势互补,从而提高项目公司的整体效率。此外,也要针对不同领域和不同地区PPP项目的特点和对投资者的要求,有针对性地选择投资者,充分发挥国企资金实力雄厚和民企专业技术的优势,提高融资效率,助力PPP实践的可持续发展。 相似文献
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S. P. Popov 《Computational Mathematics and Mathematical Physics》2007,47(1):151-156
The interaction between shock waves and rarefaction waves is numerically studied using the one-dimensional Euler equations for an ideal gas. A specific form of solutions, which are called contact regions, is detected. They represent extended zones with continuously varying density and temperature at constant pressure and velocity. It is shown that, at long times, the solutions to the interaction problem tend to those to the Riemann problems with the contact discontinuity replaced by a contact region. 相似文献
5.
One of the greatest challenges in structural engineering nowadays is the strengthening, upgrading, and retrofitting of existing
structures. The use of fibre-reinforced polymers (FRPs) bonded to the tension face of a structural member is an attractive
technique in this field of application. The strengthening of reinforced concrete structures by means of an externally bonded
reinforcement (EBR) is achieved by gluing a FRP laminate to the concrete substrate. For an efficient utilization of the FRP
EBR systems, an effective stress transfer is required between the FRP and concrete. The paper discusses the bond behaviour
between a FRP and concrete in the case of flexural strengthening of continuous beams. With respect to this type of beams,
only a few studies have been reported, though continuous members often occur in concrete constructions. The structural behaviour
of statically indeterminate elements is typically characterized by redistributions of the internal forces. These distributions
are related to the nonlinear deformations of the beams and has also a distinct influence on the bond behaviour between the
FRP and concrete.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 44, No. 3, pp. 389–402, May–June, 2008. 相似文献