公共项目公私合作(PPP)控制权配置的决策模型

针对公私合作(PPP)项目,以VFM效果作为政府收益的评价指标,分析控制权为连续变量的情况下投资、成本和收益等变量的取值,在此基础上构建控制权配置与VFM效果的相关关系模型,结果发现,VFM效果与项目公司拥有的控制权呈二次曲线关系,因此,二次项系数、一次项系数及对称轴位置影响VFM的单调性,进而决定着控制权的最佳配置.论文基于上述原理构建控制权配置的决策模型,并通过算例验证所得模型具有较强的适用性.     

An improved SVD-based watermarking technique for copyright protection

The drawbacks of SVD-based image watermarking are false positive, robust and transparency. The former can be overcome by embedding the principal components of the watermark into the host image, the latter is dependent on how much the quantity (i.e., scaling factor) of the principal components is embedded. For the existing methods, the scaling factor is a fixed value; actually, it is image-dependent. Different watermarks need the different scaling factors, although they are embedded in the same host image. In this paper, two methods are proposed to improve the reliability and robustness. To improve the reliability, for the first method, the principal components of the watermark are embedded into the host image in discrete cosine transform (DCT); and for the second method, those are embedded into the host image in discrete wavelets transform (DWT). To improve the robustness, the particle swarm optimization (PSO) is used for finding the suitable scaling factors. The experimental results demonstrate that the performance of the proposed methods outperforms than those of the existing methods.     

蒸发结晶操作中传热温差的选择

蒸发结晶是化工生产中常见的单元操作，在其加热过程中，较高的传热温差对于强化传热效率、提高设备能力极为有利。但是，传热温差过高会引起蒸发结晶操作的不稳定，甚至造成生产装置停车，使所追求的高效率适得其反。因此，必须合理选择传热温差，以保证生产装置在高效、稳定的状况下运行。     

关于第二积分中值定理渐近性的一个注记

对于第二积分中值定理中的搴，本文给出并证明了比文献[3]更一般的结论，文献[3]的有关定理可以看成本文定理的直接推论．     

基于顾客价值的物流服务传递系统设计

物流服务传递过程设计对物流服务运营管理的具体实施、控制和改进有着重要的影响。从物流服务产品的特点出发，运用服务营销理念，研究了在竞争环境下，物流服务企业应该如何设计出流畅、高效的服务传递系统，从而保证为客户提供优质的、让客户满意的物流服务。物流服务传递系统的设计建立在完整物流服务产品设计的基础之上，设计的基本过程基于各级“内部顾客”结构，分为前台和后台设计。     

Quantum analysis of measurement results

It is shown that a stochastic matrix operator (quantum measurement matrix) may be considered in some cases as a density matrix. Results of measurements in the form of figure numbers, interconnected with a matrix of quantum measurements, are similar to quantum observable quantities determined in quantum statistical theory. __________ Translated from Izmeritel’naya Tekhnika, No. 12, pp. 3–8, December, 2006.     

Heat regulating strategy in numerical control end milling for hard metal machining

The trend in die/mold manufacturing at present is towards the hard machining at high speed to replace the electron discharge machining. Failure forms of the A1TiN-coated micro-grain carbide endmill when used for the machining of/IS SKD61 (HRC 53), a widely used material in die/mold manufacturing, are investigated. The endmill shows a characteristic that tool life decreases greatly due to the chipping when overload occurs or the rapid increase of wear when over-heat accumulation in cutting edges. As a consequence of the investigation, a strategy to regulate heat generation in the end milling process is proposed. This is accomplished by controlling the cutting arc length, i.e. the length of each flute engaging workpiece in a cutting cycle. Case studies on the slot end milling and comer rounding are conducted. The results show that the proposed strategy suggests the optimal tool path as well as the optimal pitch between successive tool paths under the cutting time criterion.     

热交换器材料优化研究

对内螺纹铜管尺寸优化、铝箔厚度减薄前后的空调热交换器进行了单体性能实验和整机性能实验对比。实验结果表明优化后的内螺纹铜管、铝箔完全满足使用要求，为节约空调热交换器材料提供了有力的依据。     

A Critical Analysis of the Quality Concept and the Scope for Quantitative Estimation

Conditions are derived providing objective values for quantitative indices. It is shown that these conditions cannot be realized for the quality of a material object and consequently quality cannot have an objective quantitative value. __________ Translated from Izmeritel'naya Tekhnika, No. 10, pp. 24–27, October, 2005.     

Intercomparison of Thermophysical Property Measurements on an Austenitic Stainless Steel

The results of an inter laboratory comparison of thermal conductivity, thermal diffusivity, specific heat capacity, and thermal expansion measurements on austenitic stainless steel in the temperature range between 20 and 1000°C are presented here. Mean values are presented for the physical properties studied. Reliable relative expanded uncertainties can be stated for the properties determined, which were achieved by applying good measurement practice, i.e., 3% for thermal expansion, 5% for specific heat capacity and thermal diffusivity, and 6% for thermal conductivity. The mean values derived from this intercomparison agree well with the results of a previous intercomparison in 1990. An erratum to this article is availabale at .