OSCAR中嵌入式SQL的设计与实现

实现了一个嵌入式SQL 系统, 支持在C 语言中嵌入SQL 语句。该系统是对象关系型数据库管理系统OSCAR 客户端的重要组成部分, 分为两部分实现: 预处理模块和ESQL 运行库。预处理模块根据ESQL 语言的语法规则分析和识别ESQL 语句, 并且转换为实现相同功能的C 语言函数调用; ESQL 运行库实现这些C 函数, 通过网络通信库与服务器端通信, 并执行SQL 语句, 返回结果值。     

The Olympic Games and the Production of the Public Realm: Mexico City 1968 and Rio de Janeiro 2016

For Brazil, which is currently the world's eighth largest economy and is tipped to become the fifth, the Olympic and Paralympic Games in 2016 represent a unique opportunity. Fernanda Canales looks at Rio de Janeiro 2016 in light of Mexico City 1968, and considers how the Games should provide an occasion for both urban regeneration and also recasting the city's often previously conflicting image for an international audience. Copyright © 2011 John Wiley & Sons, Ltd.     

Production logistics digital twins: Research profiling,application, challenges and opportunities

In the era of Industry 4.0, Production Logistic Digital Twins (PLDTs) have garnered remarkable attention from both academic and industrial communities. This is evident from the growing number of research publications on PLDTs in international scientific journals and conferences. However, given the diversity and complexity of production logistics activities, there is a pressing need for systematic literature review to chart past research and identify potential directions for future endeavors. Therefore, this study primarily focuses on the application of Digital Twins (DTs) in Production Logistics (PL). Firstly, an analysis of PLDTs research profiling is carried out based on general trends, keywords, application scenarios, and basic functions. Secondly, the functional characteristics of PLDTs are examined while summarizing their advantages and limitations across various application scenarios such as transportation, packaging, warehousing, material distribution, and information processing. And the roles played by smart technologies such as Internet of Things (IoT) in PLDTs system are discussed. Finally, possible challenges and future directions of PLDTs in industrial application are presented, accompanied by appropriate classification and extensive recommendations.     

Variations in Creep Performance of P92 Steel Within Its Composition Range: Influence of N Solubility

Underspecified composition ranges often lead to alloys with unpredictable mechanical performance. To better understand the changes in microstructure and mechanical performance associated with variations of key elements, three versions of P92 are formulated within, or close to, the specified allowable for N, B, and C ranges. Chromium and Si are also varied to influence N solubility. Different service conditions (i.e., temperature and stress) are explored. It is observed that >80% decrease in creep life occurs at 625 °C and 155 MPa for the highest B and N containing alloy. Multiscale characterization reveals key changes due to the trace element variation. The high B and N containing alloy forms deleterious BN precipitates with morphology that promotes crack nucleation and damage accumulation, but this alloy additionally forms higher fractions of beneficial MX precipitates. The alloy with the lowest B and N concentrations but greater C content shows the best creep performance—a consequence of the refined M₂₃C₆ carbide precipitate population and the absence of large-scale inclusions or BN precipitates. Calculations of creep activation energy reveal that the high B and N containing alloy is more prone to damage accumulation which causes an early onset of accelerating creep and greater minimum creep rate.