零部件通用对企业竞争战略的影响

零部件通用是目前研究的一个热点问题,但是绝大多数文章都是针对零部件通用对库存水平的影响。本文从战略的角度,分析了零部件通用对企业竞争战略的影响,发现它不仅对降低费用有着积极的影响,而且对缩短新产品开发周期、制造过程重组等方面也有着积极的作用。因此,零部件的通用性已经从战术上的节约费用上升为战略上的竞争武器。     

高炉冲渣水在采暖工程中的应用

随着我国经济的迅速发展,能源消耗不断增加,节约能源、降低能源消耗势在必行,余热利用是节约能源的一个重要环节,冶金行业高炉冲渣水作为采暖热媒可以节约大量能源。     

Fuel cycle strategies and plutonium management in Europe

An overview of current nuclear power generation and fuel cycle strategies in Europe is presented, with an emphasis on options for the management of separated plutonium in the medium to long term. Countries which have opted for reprocessing of spent fuel have had to contend with increasing inventories of separated plutonium. Of the various potential options for utilisation or disposition of these stockpiles, only light water reactor (LWR) mixed-oxide (MOX) fuel programmes are sufficiently technologically mature to be fully operational in several European countries at present. Such reprocessing-recycling programmes allow for a stabilisation of the overall separated plutonium stocks, but not for a significant reduction in the stockpile. Moreover, the quality of recycled plutonium decreases at each potential step of re-irradiation. Therefore, optimised or new ways of managing the plutonium stocks in the medium to long term are required. In the present overview we consider the most promising options for reactor utilisation of plutonium in both near-term future reactor and Generation IV systems.     

Plutonium management and Generation IV systems

This paper discusses the potential role of Generation IV nuclear energy systems in managing plutonium. It briefly reviews the Generation IV goals and their relevance to plutonium management. Each of the six selected Generation IV systems [very high temperature reactor (VHTR), gas-cooled fast reactor (GFR), sodium-cooled fast reactor (SFR), super-critical-water-cooled reactor (SCWR), lead-cooled fast reactor (LFR), molten salt reactor (MSR)] is briefly discussed. The main characteristics of each system are summarised and the capability for plutonium management indicated. The potential for the management of plutonium using Generation IV systems is briefly reviewed from a complete fuel cycle perspective to illustrate the issues in the context of a fleet of reactor and fuel cycle facilities.     

Energy use in the life cycle of conventional and low-energy buildings: A review article

A literature survey on buildings’ life cycle energy use was performed, resulting in a total of 60 cases from nine countries. The cases included both residential and non-residential units. Despite climate and other background differences, the study revealed a linear relation between operating and total energy valid through all the cases. Case studies on buildings built according to different design criteria, and at parity of all other conditions, showed that design of low-energy buildings induces both a net benefit in total life cycle energy demand and an increase in the embodied energy. A solar house proved to be more energy efficient than an equivalent house built with commitment to use “green” materials. Also, the same solar house decreased life cycle energy demand by a factor of two with respect to an equivalent conventional version, when operating energy was expressed as end-use energy and the lifetime assumed to be 50 years. A passive house proved to be more energy efficient than an equivalent self-sufficient solar house. Also, the same passive house decreased life cycle energy demand by a factor of three – expected to rise to four in a new version – with respect to an equivalent conventional version, when operating energy was expressed as primary energy and the lifetime assumed to be 80 years.     

我国核裂变能可持续发展战略研究

本文从科学技术的角度,分析我国国民经济增长对核能发展的需求,探讨我国核能的近中期发展战略构想,指出为实现其发展战略目标而应重点研究的关键科学技术与问题,并提出一些相关的政策建议,为国家制定核能中长期发展规划提供参考。     

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位于准噶尔盆地腹部的陆梁油气田是准噶尔盆地的又一个亿吨级油气田。笔者运用地球化学方法分析了陆梁油气田石炭纪—早白垩世地层水的类型、平面和纵向分布特征，将其划分为3个水文地质旋回，第一旋回为石炭系—三叠系，为深层静止开放的滞流型水力系统；第二旋回为侏罗系八道湾组—西山窑组，为中层弱开放的压实驱动型水力系统；第三旋回为侏罗系头屯河组—白垩系，为浅层强开放的重力驱动型水力系统。第一、二水文地质旋回是油气生成和初次运移的有利时期，淋滤期前的一段时间是油气二次运移和成藏的较好时期，第三水文地质旋回是油气藏破坏及次生油气藏形成的时期。     

High temperature low cycle fatigue

Fatigue at high temperature is a complex phenomenon as it is influenced by a number of time-dependent processes which become important at elevated temperatures. These processes include creep, oxidation, phase instabilities and dynamic strain ageing (DSA), acting either independently or synergistically influence fatigue behaviour, often lowering the fatigue life. Current design approaches employ linear summation of fatigue and creep damage with suitable factors on permissible damage to take care of uncertainties in interaction between cyclic and time-dependent processes. It is, therefore, important to develop a deeper understanding of the processes that occur during high temperature fatigue so that realistic life predictions could be made. Results on the high temperature fatigue behaviour of austenitic stainless steels, ferritic steels and nickel base alloys are presented here. The important mechanisms of interaction of high temperature time-dependent processes with fatigue under various conditions are discussed in detail. Emphasis is placed on cyclic stress response, fatigue life, deformation substructure and fracture behaviour. This is followed by a review of important life prediction techniques under combined creep-fatigue loading conditions. Life prediction techniques considered here include linear damage summation, strain range partitioning, ductility exhaustion approach, frequency modified and frequency separation methods, techniques based on hysteresis energy and damage rate models, and methods based on crack-cavitation interation models.     

Vegetation Change in Great Lakes Coastal Wetlands: Deviation from the Historical Cycle

Water-level change is integral to the structure and function of Great Lakes coastal wetlands, and many studies document predictable relationships between vegetation and water level. However, anthropogenic stressors, such as invasive species, land-use change, and water-level stabilization, interact to shift the historical cycle (of native vegetation migration up- and down-slope) toward dominance by invasive Typha species. Knowing from earlier studies that water-level stabilization alters the historical vegetation cycle, we asked if similar shifts can occur where water levels are not stabilized. Using historical aerial photographs of three coastal wetlands (in Lake Michigan's Green Bay, Wisconsin), we determined that habitat dominated by Typha species has expanded to eliminate wet meadow habitat. Between 1974 and 1992, linear regressions showed strong, significant relationships of both meadow area (R² ≥ 0.894; p < 0.02) and marsh area (R² ≥ 0.784; p < 0.05) to water level in all three wetlands. In 2000, meadow area was below that predicted by the historical pattern due to the landward advance of marsh habitat during a year of decreasing water levels. In the same period, land use in the wetland watersheds converted from agriculture to urban. Urbanization and the replacement of native Typha latifolia by the invasive hybrid Typha xglauca may have overwhelmed the beneficial impact of water-level fluctuation. The documentation of vegetation shifts, as herein, is an essential step in the process of preserving and restoring ecological integrity.     

CDC15, an essential cell cycle gene in Saccharomyces cerevisiae, encodes a protein kinase domain

The cell division cycle gene CDC15 is essential for the late nuclear division in the yeast Saccharomyces cerevisiae. The amino acid sequence of the 974 amino acids/110 kDa CDC15 gene product, as deduced from the nucleotide sequence, includes an aminoterminal protein kinase domain which contains a primary sequence mosaic showing patterns specific for protein serine/threonine kinases besides those for protein tyrosine kinases. Many protein kinases non-essential for growth are known. CDC15 represents an essential protein kinase like CDC7 and CDC28. A carboxyterminal deletion of 32 amino acids renders the protein inactive.