Professor H. Hashimoto,Hon. F.R.M.S

Book reviewed in this article: Thin Foil Preparation for Electron Microscopy. By P. J. Goodhew. An Introduction to the Optical Microscope. By Savile Bradbury. Techniques in Immunocytochemistry, Volume 3. Edited by G. R. Bullock and P. Petrusz. X-Ray Microanalysis in Electron Microscopy for Biologists. By A. J. Morgan. Self-Assessment in Histological Techniques. By John D. Bancroft and Brian T. Chalk. X-ray Microanalysis in Electron Microscopy for Biologists. By A. J. Morgan.     

Creep behaviour of nimonic and R.R. 59 alloys

The Ramberg-Osgood relation which adequately describes the stress-strain curve of a strain-hardening material is extended to formulate the constitutive laws for creep. The constitutive laws which describe primary creep adequately are extended to secondary creep. The results are verified for the case of R.R. 59 at 200°C, Nimonic 80A and Nimonic 90 alloys at 750°C.     

R134a、R123、R23和R14混合工质林德循环的试验研究

提出了一种新的R134a、R123、R23和R14四元混合工质林德制冷循环并做了相关的试验,主要包括制冷剂组分混合比例的确定以及分析不同比例对循环整体性能的影响。通过对不同配比下所得数据的分析比较,总结了此四元混合工质林德循环的运行特点,并提出了整个系统循环的改进方案。     

Exergy efficiency and irreversibility comparison of R22, R134a, R290 and R407C to replace R22 in an air conditioning system

This work presents an experimental comparison of exergy efficiency (EE), irreversibility at the process 1–2 (evaporator exit to compressor inlet), 2–3 (compressor inlet to condenser inlet), 3–4 (condenser inlet to expansion valve inlet), 4–5 (expansion valve inlet to evaporator inlet) and 5–1 (evaporator), and coefficient of performance (COP) of R22, and its substitutes R134a, R290 and R407C in vapor compression refrigeration system (VCRS) of an air conditioner. In addition, the effects of air temperature in the freezer with reference to environment states on irreversibility and EE have been investigated. At ?18°C air temperature in the freezer, 33°C reference environment state and 42% relative humidity refrigerants R22 and its substitutes R134a, R290 and R407C VCRSs the total irreversibilities are 665.7, 753.5, 582.1 and 677 W, and EEs are 22.9, 14.2, 26.5 and 20.6%, respectively. The refrigerant R290 is the best performer among candidate refrigerants but it suffers from flammability. Thus, R407C can considerably be used to replace R22.     

R22、R410A、R32制冷系统性能的比较与少量吸气带液循环的应用

总结了R22、R410A以及R32的大量文献并分别比较了三者的循环性能,其中针对在我国广泛推广的R32制冷剂所面临的排气温度过高的问题做了综述,并由此搭建了以R32做制冷剂的变频滚动转子式水冷机组实验台,利用AHRI标准空调工况设计试验,旨在降低压缩机排气温度的同时,亦到达系统高性能系数。研究结果表明:(1)相比于R410A制冷剂,在我国成本更低、系统循环性能更优的R32将作为R22的长期替代制冷剂来进行更加广泛而深入的研究。(2)AHRI标准空调工况下,R32的COP变化速率最佳,排气温度最高,且R410A与R22分别只占R32排气温度的36.3%与55%,但可通过不增加成本的湿压缩方法大幅降低R32的排气温度。(3)本文所建立的R32转子式制冷系统实验台可通过控制压缩机吸气口干度的方式来解决压缩机排气温度过高的问题,同时通过大量试验数据能够得出最佳吸气带液量以优化系统性能。