Calibration of the Weibull stress scale parameter, σu, using the Master Curve

This work proposes that the Weibull stress scale parameter, σ_u, increases with temperature to reflect the increasing microscale toughness of ferritic steels caused by local events that include plastic shielding of microcracks, microcrack blunting, and microcrack arrest. The Weibull modulus, m, then characterizes the temperature invariant, random distribution of microcrack sizes in the material. Direct calibration of σ_u values at temperatures over the DBT region requires extensive sets of fracture toughness values. A more practical approach developed here utilizes the so-called Master Curve standardized in ASTM Test Method E1921-02 to provide the needed temperature vs. toughness dependence for a material using a minimum number of fracture tests conducted at one temperature. The calibration procedure then selects σ_u values that force the Weibull stress model to predict the Master Curve temperature dependence of K_Jc values for the material. At temperatures in mid-to-upper transition, the process becomes more complex as fracture test specimens undergo gradual constraint loss and the idealized conditions of high-constraint, small-scale yielding assumed in E1921-02 gradually degenerate. The paper develops the σ_u calibration process to incorporate these effects in addition to consideration of threshold toughness effects and the testing of fracture specimens with varying crack-front lengths. Initial illustrations of the calibration process for simpler conditions, i.e. 1T crack-front lengths, use the temperature dependent flow properties and a range of toughness levels for an A533B pressure vessel steel. Then using the extensive fracture toughness data sets for an A508 pressure vessel steel generated recently by Faleskog et al. [Engng. Fract. Mech., in press], the paper concludes with calibrations of both m and σ_u over the DBT region and assessments of the Master Curve calibration approach developed here.     

低压省煤器在电站锅炉中的应用

针对排烟损失大的问题，某些电厂在电除尘器出口加装低压省煤器，用来加热凝结水或热网补水，从而吸收烟气热量，实际测试结果表明，对于节能降耗和保证安全运行均起到了重要作用。     

亚麻针织产品的酶整理工艺探讨

为改善亚麻针织物的舒适性能，探讨用生物酶整理工艺来提高其柔软性。选取酶剂浓度、pH值、温度和时间4个因素作为正交实验的因子，进行了四因素四水平的正交实验。通过对实验结果的分析，确定了合理的生物酶整理工艺条件。工艺参数分别为：酶整理温度为50℃，整理液pH值为5，酶剂浓度为2%，整理时间为60min,亚麻针织坯布经过这种优化的酶整理后柔软性改善效果十分显著。     

UV-vis and photoluminescent spectra of TiO<Subscript>2</Subscript> films

TiO₂ fims have been deposited on glass substrates using DC reactive magnetron sputtering at different oxygen partial pressures from 0. 10 Pa.to 0.65 Pa. The transmittance (UV-vis) and photoluminescence (PL) spectra of the films were recorded. The results of the UV-vis spectra show that the deposition rate of the films decreased at oxygen partial pressure P(O₂)≥0.15 Pa, the band gap increased from 3.48 eV to 3.68eV for direct transition and from 3.27 eV to 3.34 eV for indirect transition with increasing the oxygen partial pressure. The PL spectra show convincingly that the transition for films was indirect, and there were some oxygen defect energy levels at the band gap of the films. With increasing the O₂ partial pressure, the defect energy levels decreased. For the films sputtered at 0.35 and 0.65 Pa there were two defect energy levels at 2.63 eV and 2.41 eV, corresponding to 0.72 eV and 0.94 eV below the conduction band for a band gap of 3.35 eV, respectively. For the films sputtered at 0.10 Pa and 0.15 Pa, there was an energy band formed between 3.12 eV and 2.06 eV, corresponding to 0.23 eV and 1.29 eV below the conduction band. ZHAO Qing-nan : Born in 1963 Funded by Natural Science Foundation of Hubei Province, China.     

火电厂锅炉火用损失大不等于节能潜力大

本文通过对电厂锅炉火用损失的进一步分析计算，认为现有锅炉火用损失之大部分是不可避免的，“锅炉火用效率可以大幅度提高”的观点是不切实际的。文章对火电厂节能工作具有一定的指导作用。     

φ800mm铸造轧辊热处理节能探讨

试验通过改变直径800mm铸造轧辊热处理时的加热速度和保温时间，确定了较佳的工艺规程，取得了明显的节能效果．     

An Attempt at the Classification of Energy Decaying Schemes for Structural and Multibody Dynamics

This paper analyzes the formulation of energy preserving/decaying schemes for dynamics problems. We argue that any energy preserving/decaying scheme can always be seen as composed of an underlying temporal discretization, that is then slightly modified in order to prove a discrete energy bound within a time step. While the details of the modified scheme depend in a critical way on the governing equations, the underlying discretization can in principle be applied to a variety of models. We review some of the temporal underlying schemes recently proposed in the literature, presenting them with a common notation. We show their similarities and highlight their differences.     

Growth and optical properties of Er,Yb:YAl3(BO3)4 crystal

Single crystal of erbium, ytterbium-codoped yttrium aluminum tetraborate Er,Yb:YAl₃(BO₃)₄(Er,Yb:YAB) has been grown by the flux method. The absorption spectrum in the visible and NIR regions of Er,Yb:YAl₃(BO₃)₄ crystal are measured at room temperature and fluorescence spectrum of Er,Yb:YAl₃(BO₃)₄ crystal are also measured at room temperature, excited by 976 nm laser. Not only the strong NIR emission peaks located at 1548 nm was observed, but also the visible up-conversion luminescence has been found. The specific heat of the Er/Yb:YAB crystal at room temperature is 0.81 J/g °C.     

Synthesis and characterization of thorium phosphate phases by spray pyrolysis: chemistry of thorium phosphates

This paper describes the synthesis of some thorium phosphate compounds with different Th/P ratio (1/2, 2/3 and 3/4) by a spray pyrolysis technique. The so-prepared rough compounds were annealed at different temperatures for 2 h and then analyzed by mainly X-ray diffraction on powder and infrared spectroscopy. Every rough compound is composed by very badly crystallized ThO₂ phase polluted by carbon residue. An annealing treatment at 800 °C leads to the thorium diphosphate phase, α-ThP₂O₇ in every case. At 900 °C, such a phase is decomposed into a thorium phosphate diphosphate phase (Th₄(PO₄)₄P₂O₇, called TPD). However, a thorium excess in the initial mixture (Th/P = 3/4) leads also to observe the ThO₂ phase. The TPD phase is stable up to 1200 °C and does not react with the ThO₂ compound. Beyond 1200 °C, the TPD phase is slowly decomposed into a thorium phosphate compound which should be a thorium oxide phosphate; this compound does not contain any diphosphate species.     

我国能源工业现状和能源政策

能源工业是我国国民经济的重要组成部分。要实现“十六大”提出的2020年国内生产总值翻两番的宏伟目标，充足、稳定、经济、清洁的能源供应是重要的物质保障。文中从能源产量与需求、能源结构优化、能源技术水平、能源体制改革、能源可持续发展、农村能源建设、能源效率等方面对我国能源工业现状进行深入分析，在此基础上指出未来中国的能源政策应包括5个方面：优化能源结构、提高能源效率、重视环境保护、保障能源安全、开发西部能源。