Influence of Al and Ni concentration on the Martensitic transformation in Cu-Al-Ni shape-memory alloys

The martensitic transformation temperatures and the types of martensitic phases have been determined in a wide concentration range of technological interest for Cu-Al-Ni shape-memory alloys (SMAs) A stability diagram of martensitic phases as a function of alloy concentration has been determined. It is found that when the aluminum content increases, the transformation changes from β ₃ ⇒ β′₃ to β ₃ ⇒ γ′₃, with an intermediate concentration range where both martensites coexist due to a β ₃ ⇒ γ′₃+β′₃ transformation. On the other hand, an increase of nickel content stabilizes the martensite β′₃, changing from a mixed β ₃ ⇒ γ′₃ + β′₃ to a single β ₃ ⇒ β′₃ transformation. Furthermore, linear relationships between M _s and Al and Ni concentrations have been obtained for all types of martensitic phases.     

宽带接入服务器的选择配置和应用

本文主要分析了影响宽带接入服务器性能的各种因素，介绍了如何选择宽带接入服务器，并针对REDBACK公司的SMS1800和UNISPHERE公司的ERX1400两种典型宽带接入服务器说明如何进行配置，为应用宽带接入服务器提供参考。     

再造鼓形膨胀器

介绍了本钢不停产安装再造煤气管道鼓形膨胀器的实践，并对制造、安装方法进行了叙述，特别是在结构上采用了独特的构槽密封焊缝和完整的安装程序，保证了实施的安全。     

β-hydroxyacyl-coa-dehydrogenase (HADH) activity of unfrozen and frozen—thawed frog (Rana esculenta) legs

The β-hydroxyacyl-CoA-dehydrogenase (HADH) activity of unfrozen and thawed frog legs was investigated. The enzyme was extracted by either immersing frog legs in phosphate buffer 0.1 M, pH 6.0 at 25°C for 15 min or pressing them between trichinoscopy glasses. The enzyme activity was assayed using acetoacetyl-CoA as substrate and measured spectrophotometrically at 340 nm. It was possible by both extraction methods to distinguish between thawed and unfrozen samples although when the juice was obtained by pressing the HADH activity of the dilution was ～ 1.5 times higher than that obtained by immersion. The HADH activity was significantly higher (P≤0·001) in frozen-thawed frogs than in unfrozen legs because during freezing there is a release of HADH. No significative differences were found in the HADH activity in samples frozen in the temperature range -10 to -196°C. HADH activity was not affected by the storage time in crushed ice up to 6 days.     

Using artificial intelligence to model heavy plate mill rolling

This research summary discusses the application of neural networks, evolutionary strategies, and other artificial intelligence techniques in the modeling and optimization of the models used for temperature, rolling force, and torque calculation in heavy plate milling.     

Optical properties of amorphous carbon thin films prepared by plasma deposition in a graphite hollow cathode

Carbon films have been produced using a graphite hollow cathode and an r.f. plasma of hydrogen or hydrogen and argon. No hydrocarbon gas was used. The films were subjected to heat treatments up to 700 °C in air. The optical properties of the films were studied using Fourier transform IR, UV-visible, Raman, ellipsometry and photoluminescence techniques before and after the annealing. Films prepared without argon have a narrower band gap and a different photoluminescence response from films prepared with argon. The index of refraction was seen to have values between 1.7 and 2.2 depending on the preparation conditions. The optical band gap of the films was generally greater than 2 eV and the annealing process both increased the gap and reduced the density of states responsible for the large photoluminescence signal.