偏光显微镜法在空气粉尘中石棉纤维鉴别中的应用

本文采用偏光显微镜法鉴别空气粉尘中的微量石棉纤维。经滤膜收集的粉尘样品通过高温灰化及酸洗过程去除大部分干扰物质,经乙醇分散后均匀沉积在玻璃片上,滴加具有固定折射率的浸油制成试片。在正交偏光系统下观察到粉体中存在纤维状颗粒,且纤维呈现四次平行消光特性,比对6种常见石棉的偏光显微镜图,综合分析试样粉尘的光学性质,推断样品中含有温石棉。     

Preventing motor vehicle crash injuries and deaths: science vs. folklore lessons from history

Abstract

Not long after the beginnings of motorization in the early 1900s, deaths and injuries from motor vehicle crashes became a problem in a number of high-income-countries (HIC)s, especially the United States. With the biggest problem the US led early efforts to address this issue, and for six decades these efforts were based on folklore (ie a body of widely held but false or unsubstantiated beliefs). They were not evaluated, but clearly were unsuccessful as crash deaths and injuries continued to rise. It was not until the 1970s that a broader range of countermeasures began to be adopted and was scientifically evaluated, and as a result, crash deaths and injuries declined. This history has important lessons today for many low-and-middle-income countries that have growing numbers of motor vehicle crash deaths and injuries, many of which are pedestrians and motorcyclists. This is because there continue to be advocates for many of the failed approaches (especially educational) that dominated the early efforts in HICs.     

空间目标的联合矩阵束极点估计

极点作为谐振区雷达目标的最主要电磁特性，具有很大的空间目标识别前景。但是在使用频域观测数据提取目标极点时，存在虚假极点和估计精度问题。针对上述问题，首先通过加窗和截断改进了后时响应信号的获取流程，抑制了虚假极点影响；然后采用最小描述长度法（MDL）估计极点个数，避免了定阶错误引起的虚假极点；最后采用联合矩阵束法估计极点，有效减少了单角度数据估计极点时存在的遗漏极点和虚假极点问题。FEKO软件验证表明，所提算法具有更高的精度和抗噪能力。     

The challenge of Chinese state‐affiliated multinationals in benefiting from foreign subsidiary knowledge transfer: A criticism of light‐touch integration

Acknowledging the sharp growth of Chinese state‐affiliated multinationals and their strategic asset‐seeking investments abroad, this study investigates the effects of headquarters' home‐country political ties on the multinational‐wide benefits gained from subsidiary knowledge transfer in Chinese multinationals. It also looks at how these effects are mediated by organizational distance and social integration between headquarters and subsidiary. Based on a survey of 177 subsidiaries of 99 Chinese multinationals, we find that headquarters' political ties trigger organizational distance and hinder social integration between headquarters and foreign subsidiaries and these, in turn, hamper the potential benefits that Chinese multinationals derive from subsidiary knowledge transfer. This study identifies new challenges related to political ties and light‐touch integration in gaining benefits from subsidiary knowledge transfer.     

TiO2光催化氧化研究进展

本文着重介绍了光催化氧化反应的特点，TiO2的性质及光催化的原理，TiO2光催化剂的制各方法及其应用，提出目前存在的问题，对研究开发方向做了展望。     

机载机柜的隔振设计

针对机载电子设备所处的振动环境,结合振动理论,阐述了一种机载机柜隔振设计的方法.该方法有助于提高系统的抗振能力.     

基于DMSP/OLS夜间灯光数据的土地城镇化水平时空测度研究——以环渤海地区为例

在遥感和GIS技术支持下,发展出一种基于长时间序列DMSP/OLS夜间灯光数据的土地城镇化水平测度方法,并以环渤海地区为例进行1992—2010逐年土地城镇化水平时空测度研究。结果表明,在1992—2010年间:1基于DMSP/OLS夜间灯光数据提取的城镇用地信息总体精度和Kappa系数平均值分别达到了88.11%和0.61,能较好地反映区域城镇发展的实际情况,具有一定的可信度;2从总体上看,环渤海地区土地城镇化水平增长迅速,由1992年的0.82%增至2010年的3.20%,年均增长率指数为7.80%;3从区域差异上看,环渤海地区三大城市群之间、滨海城市与非滨海城市之间、距海岸线不同距离的区域之间土地城镇化水平差异显著并呈进一步扩大趋势;4从空间特征上看,土地城镇化水平高值区呈现出一定的向海性。本研究可为快速有效地测度分析区域土地城镇化水平,进而调整和优化区域城镇化格局,推进区域新型城镇化建设提供决策参考。     

Understanding the exploration–exploitation dilemma: An fMRI study of attention control and decision‐making performance

This paper studies the cognitive processes that enable decision makers to switch between exploitation and exploration. We use functional magnetic resonance imaging (fMRI) in a sample of expert decision makers to make two main contributions. First, we identify and contrast the specific brain regions and cognitive processes associated with exploitation and exploration decisions. Exploitation activates regions associated with reward seeking, which track and evaluate the value of current choices, while exploration relies on regions associated with attentional control, tracking the value of alternative choices. Second, we propose and test the idea that stronger activation of the brain circuits related to attentional control allows individuals to achieve better decision‐making performance as a result. We discuss the implications of these results for strategic management research and practice. Copyright © 2013 John Wiley & Sons, Ltd     

City Size,Population Concentration and Productivity: Evidence from China

This paper investigates the impact of China's city size and urban population concentration on city productivity by developing a distinctive index based on global nighttime light data. Using the panel data of 280 prefecture cities from 2004 to 2013 and employing dynamic system generalized method of moments and panel threshold model regression techniques, our results show that city size has a positive impact on city productivity; therefore, cities in China still have the potential to expand. While moderate urban population concentration can benefit city productivity, excessively concentrated urban population distribution may impede the growth of city productivity. We also find that the level of labor income significantly affects the impacts of urban agglomeration on labor productivity. Therefore, our results imply that city development policies should focus more on how to appropriately allocate economic activities and adjust population distribution in urban areas according to different stages of economic development.     

An empirical analysis of night-time light data based on the gravity model

This article aims to explore the feasibility of applying night-time light data to the study of trade. Based on 61 countries’ panel data from 1995 to 2012, this research used night-time light data, as the substitute for GDP, to study trade development based on the traditional gravity model. The method of ordinary least squares, Poisson pseudo-maximum-likelihood and two-stage least squares were used. The results show that geographical distance, country borders and regional agreements have a significant effect on China’s trade with other Belt and Road countries, which verifies the validity of trade research based on night-time light data analysis. Additionally, comparisons reveal the trade trends predicted by night-time light data from 1996 to 2012, were highly consistent with the actual data. This article stands as the first study to apply night-time light data to the gravity model in the research on trade between China and other Belt and Road countries. Breaking new ground, this research uses night-time light data as an economic indicator to study trade, in combination with micro foundations and the latest findings of the gravity model. Thus, this article deepens the understanding of trade analysis and contributing to the field of related researches.