Ab INITIO COMPUTATIONAL MODELS IN MATERIALS SCIENCE: A COMMON PLAYGROUND FOR SURFACE CHEMISTRY AND SOLID-STATE PHYSICS

This article describes the usefulness of embedded cluster and periodic models to solve a number of problems in computational materials science. To this end, two different well-defined problems are selected and discussed. The first problem concerns magnetic coupling in high Tc superconductor parent compounds. It is taken to exemplify the application of quantum chemical methods to derive excited-state properties of extended systems. The second problem concerns the selectivity of a partial oxidation reaction catalyzed by a metal surface. This second example serves to illustrate the efficacy of solid-state band theory methods in the study of chemical reactions taking place at surfaces. Possible extensions of ab initio computational materials science are further discussed.     

高密度-低温柴油机燃烧理论与技术的研究与进展

本文以节能和超低排放为目标,先后开展了"早喷"预混压燃燃烧,稀扩散燃烧和复合燃烧等理论与技术的研究.阐述了其基本技术路线、优势和局限性.在此基础上.作者课题组提出了柴油机燃烧过程混合和化学时间尺度控制及燃烧路径控制概念,最终形成了高密度.低温燃烧理论,并在实验发动机上通过燃烧电子控制技术的创新实现了在欧V排放水平上柴油机高热效率和简化或取消后处理器的目标.     

悬吊氯化铵溶液液滴的结晶过程

研究了常温下悬吊氯化铵溶液液滴的结晶过程,讨论了初始液滴的大小、氯化铵浓度以及悬吊细丝对结晶过程的影响.在实验中观察到了沿液滴表面枝晶的生长过程,发现液滴成壳后的表面形态与成核时的液滴直径之间有一定的关系.为了深入了解声悬浮条件下溶液液滴的结晶过程,将两种不同条件下的结晶过程进行了比较,并由此对声悬浮液滴结晶过程做出一些推断.     

略论创新与企业文化

创新管理是企业发动力。进入９０年代以来,知识经济时代要求企业管理观念创新,运行机制转轨。在社会变革的时代,企业文化已成为企业生存的基础,发展动力,行为的准则和成功的关键。在塑造优秀的企业文化过程中,要用市场经济的要求塑造人,培养人,树立正确的价值观。运用ＣＩ战略塑造企业形象,形成高品位,高要求,高回报的文化特征,从而真正焕发现代企业的活力和风采。     

A human-machine interface evaluation method: A difficulty evaluation method in information searching (DEMIS)

A human-machine interface (HMI) evaluation method, which is named “difficulty evaluation method in information searching (DEMIS)”, is proposed and demonstrated with an experimental study. The DEMIS is based on a human performance model and two measures of attentional-resource effectiveness in monitoring and detection tasks in nuclear power plants (NPPs). Operator competence and HMI design are modeled to be most significant factors to human performance. One of the two effectiveness measures is fixation-to-importance ratio (FIR) which represents attentional resource (eye fixations) spent on an information source compared to importance of the information source. The other measure is selective attention effectiveness (SAE) which incorporates FIRs for all information sources. The underlying principle of the measures is that the information source should be selectively attended to according to its informational importance. In this study, poor performance in information searching tasks is modeled to be coupled with difficulties caused by poor mental models of operators or/and poor HMI design. Human performance in information searching tasks is evaluated by analyzing the FIR and the SAE. Operator mental models are evaluated by a questionnaire-based method. Then difficulties caused by a poor HMI design are evaluated by a focused interview based on the FIR evaluation and then root causes leading to poor performance are identified in a systematic way.     

Effects of graduated driver licensing on licensure and traffic injury rates in Upstate New York

Objective

In 2003, New York State implemented an enhanced graduated driving licensing (GDL) program that requires extended supervised driving and a passenger restriction. This study examines its safety benefit in 55 Upstate New York counties.

Methods

We analyzed fatal/incapacitating traffic injury data among 16-, 17- and 21-24-year olds for the years 2001 and 2005 using the negative binomial model. To adjust for trends in the traffic injury rate, the relative rate ratio (rRR) of 16- and 17-year olds relative to 21-24-year olds was estimated.

Results

GDL implementation was associated with a 31% reduction in the driver injury rate (rRR 0.69, 95% confidence interval (CI) 0.49-0.96), but not with any statistically significant change in the passenger injury rate (rRR 1.19, 95% CI 0.77-1.84), or pedestrian and bicyclist injury rate (rRR 1.53, 95% CI 0.89-2.62) among 16-year olds. Sixteen-year olds experienced a 21% decline in licensure rates between 2001 and 2005. GDL implementation had no appreciable impact on driver injury and licensure rates for 17- and 21-24-year olds.

Conclusions

GDL implementation is associated with a significant reduction in licensure and driver injury rate among 16-year olds. GDL implementation does not have a statistically significant impact on passenger, pedestrian, and bicyclist injury rates for 16-year olds.     

核电常规岛及BOP部分全开全关电动门逻辑图标准化设计的改进

分析了岭澳一期核电站"常规岛及BOP部分"全开全关电动门逻辑图设计存在的问题。在岭澳二期设计过程中,结合本期工程的设计原则,提出了逻辑图标准化设计的解决方案,使设计效率大大提高。     

一种面向电力调控云的高效运维方法

随着云计算、大数据、人工智能等IT新技术的不断发展,依托其构建的电力调控云规模不断扩大,相应的电力调控云应用服务数量也随之成倍增加,使得它们电力调控云的运维复杂度加大,运维任务量加重,基于人工的运维模式效率低下、出错率较高。持续集成、持续部署(CI/CD)平台可对电力调控云进行高效、精准的自动化维护。通过引入一种面向电力调控云的高效运维方法,执行完成电力调控云产品的自动化构建、版本控制、批量部署等运维任务。最后通过对电力调控云平台的仿真实验,验证了该方法可以减轻运维任务量,提升工作效率。     

基于偏相关性测试的递归式因果推断算法

因果推断是挖掘事物间联系的一种重要方式,但在高维数据场景下,利用因果推断算法进行条件独立性（CI）测试存在冗余测试多和测试效率低的问题,这限制了因果推断在高维数据集上的应用。提出一种基于偏相关性测试的递归式因果推断算法。采用“分治”的方法对变量集进行递归式因果分割,得到更易于处理的低维子数据集,提高对数据集的处理效率。在每个子数据集上进行局部因果推断,减少每次因果推断的计算量并提升算法的运行速度。在此基础上,通过比较显著性值的合并策略整合所有子结果并得到完整的因果关系,保证总体因果结构的准确性。在“分治”过程中,采用高效的偏相关性测试避免高复杂度的核密度估算,进一步提升算法效率。基于10个经典数据集的实验结果表明,在准确率与经典推断算法CAPA持平的情况下,该算法的运算速度提升了2~10倍,且在样本量越大的数据集中提升效果越明显,证明递归式因果推断算法可以有效处理高维数据集,在保证准确率的同时提高运算效率。     

压缩感知理论及其在成像技术中的应用

在传统的Shannon/Nyquist采样定理指导下,信号处理往往面临两大难题:A/D转换器技术的限制和海量采样数据的处理压力.压缩感知(CS)理论表明当信号具有稀疏性或可压缩性时,可以通过全局非自适应线性投影的方式,用远低于Shannon/Nyquist采样定理要求的频率获取信号的全部信息.以CS理论为基础的压缩成像(CI)技术在近年来得到了快速的发展.在概述CS理论的基础上,着重介绍了CI技术的原理及其发展状况,并从稀疏分解、观测矩阵的构造和重建算法3个方面对其关键问题进行了分析.CI系统可以显著节省感光器件的数量,避免了传统成像技术"先采样再压缩"方式带来的资源浪费.