Optimum thermoeconomic and thermodynamic performance characteristics of an irreversible three-heat-source heat pump

The coefficient of performance and specific heating load of an irreversible three-heat-source heat pump are given by using a general cycle model affected by the finite-rate heat transfer, heat leak and internal irreversibility of the cyclic working fluid. The heat pumping load divided by the total cost per unit time is taken as a new objective function and used to investigate the performance of the heat pump. The thermoeconomic and thermodynamic performance characteristics of the heat pump are discussed in detail. Some important performance parameters such as the thermoeconomic objective function and coefficient of performance are optimized. The optimally operating regions of the heat pump and the bounds of several performance parameters are determined. Finally, it is pointed out that the Carnot heat pump may be taken as a special case of a three-heat-source heat pump and consequently its optimal performance can be directly derived from the results obtained here.     

元刊杂剧特指式反问句

详细描写了元刊杂剧特指式反问句的结构及意义，指出反问句用疑问句的形式表达与语表形式相反的“言外之意”，其基本语用意义是评价，特指式的反问意义是在具体的语言环境中形成的。     

Prediction of the twisting moment and axial force in a circular rubber cylinder for combined extension and torsion based on the logarithmic strain approach

The scope of the present work is the application of a particular class of strain energy function, based on the logarithmic strain, for the prediction of the twisting moment and axial force of a rubber circular cylinder under combined extension and torsion. The strain energy function involves four material parameters three of which are determined by fitting published experimental data from simple tensile and compression tests of natural rubber. One of the parameters of the proposed model has physical meaning, and it is equal to one ninth of the initial modulus of elasticity of the material. Hence, the number of unknown parameters is reduced to three. The logarithmic strain energy function is then applied to a combined extension and torsion problem of a rubber circular cylinder to check its performance for more complicated deformations. The results are compared with corresponding experimental and theoretical solutions available in the literature to validate the proposed model. It is found that the proposed strain energy function apart from predicting the common modes of deformations is also capable to determine more complicated types of deformation. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

粘接结构超声信号的小波分解与特征提取

粘接结构因其独特的物理、机械和声学特性在诸多领域具有非常广泛的应用，对于铝合金-橡胶这样一种金属-非金属粘接结构的超声检测信号，本文利用了小波变换的多分辨率分析(时频分析)的方法，有效地提取出了反映多层材料粘接状况的信号特征，该特征提取方法可用在粘接结构的无损检测中。     

非标压力机箱形主梁全约束优化设计

根据非标设备结构优化问题的特点,给出满足《钢结构设计规范》(GBJ17 88)规定的箱形主梁全约束优化设计方 法。将编制的内罚函数法优化程序应用于主梁的设计,计算结果表明,该优化方法可应用于实际设计。     

ROI-based Watermarking Scheme for JPEG 2000

A new region of interest (ROI)-based watermarking method for JPEG 2000 is presented. The watermark is embedded into the host image based on the characteristics of the ROI to protect rights to the images. This scheme integrates the watermarking process with JPEG 2000 compression procedures. Experimental results have demonstrated that the proposed watermark technique successfully survives JPEG 2000 compression, progressive transmission, and principal attacks.     

井底堆积物的作用

分析了深井低品位岩溶采卤中，井底堆积物的形成和发展，利用流体力学理论，从正反两方面分析了井底堆积物在采卤中的主要作用。     

SARS流行预测分析

表面上突如其来的SARS本质上却有极规律的内在发展演化机制，遵从初始缓慢增长、加速、减速和稳定终止四个阶段总体道路，自然和社会生活领域众多事件演化都符合这一规律，因而可以运用广义的Logistic生长模型进行描述。基于先期流行的广东SARS感染病例数据，以及尚未结束的北京、全国2003年SARS流行统计数据，借助于最优化分析技术，运用广义的Logistic生长模型对该事件演化特征参量进行了辨识；在此基础上，又借助于广义生长模型的特例——Gompertz函数进行了演化过程的预测，并与其他生长模型结果进行了比较。研究表明，生长模型模拟结果均与实际数据有很好的一致性，可以用来预测事件的发生演化过程，此次SARS事件堪称生长模型的经典实例。     

多层砖砌体房屋震害分析及抗震措施

介绍了我国砖砌体房屋历年来遭受震害的程度以及砖砌体的抗震性能，针对一些震害现象，分别从建筑布置和抗震措施加强对砖砌体的抗震性能进行论述。     

浅析英语语音音变对听力理解的影响

针对英语教学过程中影响听力理解的语音音变问题，章分析了语音音变现象，如音的浊化、音的同化、音的不完全爆破、音的连读等等，并提出了有效可行的解决途径，帮助英语学习更好地掌握语言的交汇功能。