镍诱导纳米晶硅薄膜的生长

采用磁控溅射方法制备了含镍过渡层的富纳米晶硅二氧化硅薄膜．对薄膜退火后的微观结构和发光性能进行了试验分析．结果表明,在高温退火后,有Ni过渡层的富纳米晶硅薄膜较没有Ni过渡层的薄膜具有更高的纳米晶硅密度和更强的室温光致发光强度．对试验结果进行热力学分析后,认为NiSi2作为纳米晶硅的形核中心诱导了薄膜的分相和纳米晶硅生长．     

加快建设国家科研论文和科技信息高端交流平台

构建国家科研论文和科技信息高端交流平台是加强国家战略科技力量的重要举措之一.在系统梳理我国科研论文和科技信息交流平台建设现状的基础上,指出目前存在资源分散、规模尚小、重复建设、开放度低、专业性不足、功能不完善、交流不通畅等问题,缺乏吸纳全球科研成果的平台或载体,难以从创新链和产业链的角度整合技术供给体系,进而提出整合国...     

我国煤炭开发利用中跨区域产业联动的可行性分析

产业链研究不仅对产业发展有重要意义,而且对区域经济的发展日益重要。基于产业链的跨区域延伸,首先提出了跨区域产业联动的概念;进而从区域经济角度对我国煤炭产业链的现状进行了具体分析,阐述了所存在的问题,在此基础上指出了煤炭开发利用中进行跨区域产业联动的必要性。     

细长受压杆的分岔特性研究

利用Lagrange描述法建立了受压细长杆因弯曲引起的轴向位移与横向位移之间的关系,并建立了由偏微分方程组描述的非线性动力学模型.通过对偏微分方程组的简化,得到了仅含三次非线性项的非线性动力学模型,并利用谱截断方法对此模型进行降阶.利用Lyapunov第一近似理论讨论了降阶模型的分岔特性.研究表明,受压细长杆在弯曲过程中Lagrange坐标的不变性为研究其动力学行为带来极大的便利,压杆的稳定性分析宜采用Lagrange描述法;当忽略杆由压缩引起轴向位移时,由弯曲引起的轴向位移与横向位移之间不存在耦合作用;当轴向压力小于某个值时,压杆只有直线一种平衡状态,且为稳定的;当大于这一值时,直线平衡状态失去稳定性而分支出两个稳定的非直线平衡状态,因而发生叉形分岔.     

基于最小费用流模型的不正常航班恢复问题研究

突发事件会导致航班计划无法按原计划执行,给航空公司及旅客带来巨大损失。而航班恢复问题的难点除了相关因素的复杂性,主要的体现在恢复方案的即时性。因此,为了提出快速有效的航班恢复方案,以降低损失,笔者通过时空网络技术对不正常航班的恢复问题进行描述,实现了对航班在空间和时间上的追踪。基于最小费用流模型,建立了以最小总延误时间为目标函数的整数规划模型,模型同时考虑了航班延误,飞机置换及航班取消的调度策略,并提出采用Floyd-Warshall算法对建立的模型进行求解。最后,通过算例对模型及算法进行验证。研究结果表明:针对突发状况,建立的模型及算法可提出合理的航班恢复方案,证明了模型及算法的可行性及有效性。建立的模型具有普适性,对不正常航班恢复问题的研究具有借鉴意义。     

医疗资源可达性与居民就医行为研究进展

医疗资源配置与居民就医行为分别反映了医疗系统的供给和需求两个侧面,相关研究对于推进基本公共服务均等化、解决医疗资源的供需结构性矛盾具有重要意义。地理学长期关注医疗资源的可达性,但对于就医行为的关注有所不足;而医疗和公共卫生领域的就医行为及其影响因素研究的空间视角相对缺乏。本研究对地理学和医疗卫生领域已有的医疗资源可达性和就医行为研究进行了梳理,构建了"空间-就医-健康"研究框架,以人文地理与城市规划的学科理论为基础,将行为主义、可达性模型、就医行为决策模型等方法论相结合,从微观个体的视角出发,试图探讨医疗资源可达性、就医行为、健康3者之间的关系,以期为后续研究提供参考。     

基于支持向量回归的定性-定量因子混合建模方法

在科学研究及工程实践中,输入参数经常同时包含定性因子与定量因子,为实现此类数据的有效建模,提出基于支持向量回归(SVR)的定性-定量因子建模方法,以用于工程实验及数值仿真的定性定量因子分析.引入超球面分解量化定性因子相关关系,构建了一种新型核函数描述定性因子与定量因子关联关系,提出了定性-定量因子支持向量回归算法实现定性定量数据的混合建模与预测.通过数值算例和经典工程算例,发现所提算法能提供相比于普通的支持向量回归算法及基于高斯过程回归的定性-定量因子算法更优的预测结果.以种植体骨应力分析为例,其中种植体材料类型为定性因子、结构参数为定量因子,实验结果表明所提算法能够显著提升骨应力预测精度,可为种植体的设计优化提供模型基础,揭示了所提算法的工程可用性.     

Progress in bionic information processing techniques for an electronic nose based on olfactory models

As a novel bionic analytical technique, an electronic nose, inspired by the mechanism of the biological olfactory system and integrated with modern sensing technology, electronic technology and pattern recognition technology, has been widely used in many areas. Moreover, recent basic research findings in biological olfaction combined with computational neuroscience promote its development both in methodology and application. In this review, the basic information processing principle of biological olfaction and artificial olfaction are summarized and compared, and four olfactory models and their applications to electronic noses are presented. Finally, a chaotic olfactory neural network is detailed and the utilization of several biologically oriented learning rules and its spatiotemporal dynamic propties for electronic noses are discussed. The integration of various phenomena and their mechanisms for biological olfaction into an electronic nose context for information processing will not only make them more bionic, but also perform better than conventional methods. However, many problems still remain, which should be solved by further cooperation between theorists and engineers. Supported by the National Creative Research Groups Science Foundation of China (Grant No. 60421002) and National Basic Research Programme of China (Grant No. 2004CB720302)     

A non-commutative time-frequency tomography

The characterization of non-stationary signal requires joint time and frequency information. However, time and frequency are a pair of non-commuting variables that cannot constitute a joint probability density in the time-frequency plane. The time-frequency distributions have difficult interpretation problems arising from negative and complex values or spurious components. In this paper, we get time-frequency information from the marginal distributions in rotated directions in the time-frequency plane. The rigorous probability interpretation of the marginal distributions is without any ambiguities. This time-frequency transformation is similar to the computerized axial tomography (CT or CAT) and is applied to signal analysis and signal detection and reveals a lot of advantages especially in the signal detection of the low signal/noise (S/N).     

Mechanism of the interaction between Au nanoparticles and polymerase in nanoparticle PCR

Nanoparticle PCR is a novel method to optimize DNA amplification. It performs well in improving specificity, enhancing sensitivity and speed. Several mechanisms were proposed in previous studies: one was based on the interaction between gold nanoparticles (AuNPs) and DNA while the other was attributed to the heat transfer property of AuNPs. In this paper, we propose that the interaction between AuNPs and DNA polymerase can significantly influence PCR. First, the addition of DNA polymerase can eliminate the inhibitory effects of excess AuNPs. Second, the addition of AuNPs will increase yield of the desired PCR product and make the optimum concentration of DNA polymerase move to higher value. Third, while excess polymerase might inhibit amplification efficiency, AuNPs can reverse this process and the yield of PCR amplification. Based on these results we propose a possible mechanism that AuNPs might modulate the activity of polymerase and improve PCR amplification.