New approach to enhance adhesions between carbon nanotube emitters and substrate by the combination of electrophoresis and successive electroplating

Complementary electroplating combined with electrophoresis enhanced the field emission characteristics of emitters by improving the adhesions between CNT emitters and substrate. The emitting current of the CNT emitters prepared by our combined method increased nine times higher than that of CNT emitters prepared by electrophoresis only, since electroplating improved the adhesion of CNT emitters. During the life-time measurement for 10 h, the emitting current of CNT emitters fabricated by electrophoresis only was drastically decreased to 13% of the initial current, while that prepared by the combination of electrophoresis and successive electroplating decreased to 64% of the initial current. We suggest that our method is a promising approach for the efficient fabrication of reliable CNT emitters.     

Linear mixture model applied to Amazonian vegetation classification

Many research projects require accurate delineation of different secondary succession (SS) stages over large regions/subregions of the Amazon basin. However, the complexity of vegetation stand structure, abundant vegetation species, and the smooth transition between different SS stages make vegetation classification difficult when using traditional approaches such as the maximum likelihood classifier (MLC). Most of the time, classification distinguishes only between forest/non-forest. It has been difficult to accurately distinguish stages of SS. In this paper, a linear mixture model (LMM) approach is applied to classify successional and mature forests using Thematic Mapper (TM) imagery in the Rondônia region of the Brazilian Amazon. Three endmembers (i.e., shade, soil, and green vegetation or GV) were identified based on the image itself and a constrained least-squares solution was used to unmix the image. This study indicates that the LMM approach is a promising method for distinguishing successional and mature forests in the Amazon basin using TM data. It improved vegetation classification accuracy over that of the MLC. Initial, intermediate, and advanced successional and mature forests were classified with overall accuracy of 78.2% using a threshold method on the ratio of shade to GV fractions, a 7.4% increase over the MLC. The GV and shade fractions are sensitive to the change of vegetation stand structures and better capture biophysical structure information.     

Plasma properties of laser-ablated St target in air

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MIM隧道结的电子输运特性和发光研究

论述作为一种新型发光器件的ＭＩＭ隧道结的发光机理，报告了该器件的发光现象和Ｉ－Ｖ特性曲线中负阻现象的实验观察。数据显示，结中表面等离极化激元（ＳＰＰ）与粗糙度的耦合是引起光发射的主要方面，ＳＰＰ对隧穿电子的阻塞作用导致了电子输运中的负阻现象。此外，还观察到了直接辐射的紫外峰。     

Method of increasing the output signal-to-noise ratio in passive multi-element antenna arrays

A method of processing complex signals in passive multi-element antenna arrays based on an analysis of the natural values of the correlation matrix of the signal is considered. By means of the method it is possible to substantially increase the output signal-to-noise ratio. An iterational process by means of which optimal estimators of both the signal and the amplitude-phase distribution may be obtained, is proposed. Theoretical estimators of the efficiency of the method are given. It is proved that, in terms of the efficiency, the approach considered in the article comes close to the technique of matched filtration. Results of statistical modeling that confirm the statistical results are presented.     

真空微电子三极管几何参数的设计考虑

真空微电子三极管是近年来兴起与发展的真空微电子学中的一类重要器件。本文从真空微三极管的工作特性出发,分析了这类器件中所需考虑的几何参数和工作特性的关系,并给出了一些理论和实验公式,为今后的设计提供一些参考。     

Red emission from Eu3+: PVA polymer film

Bright red luminescent Eu³⁺ doped polyvinyl alcohol (PVA) films were made by solution casting technique. The emission performance of these films was studied from the measurement of excitation, emission, and lifetimes. On irradiation with an UV source, the doped films emitted bright red light. Such luminescent polymer films are expected to find potential applications as new optical materials. Emission process in the system was explained by an energy level scheme. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3273–3276, 2006     

Practice characteristics that lead to 21st century learning outcomes

Abstract The key research question for this study was to ask whether or not innovative teaching practices would lead to the development of learning outcomes essential for preparing the younger generation for the challenges of life in the knowledge society of the 21st century, and if so, how are the pedagogical features related to the different learning outcomes. Preliminary analyses of the case study data collected from the SITES M2 Study in Hong Kong reveal that where the development of more significant learning gains were observed, the cases possess characteristics additional to the criteria defined in the Study for selection of innovation. More importantly, it was found that the impact of the pedagogical practices was not determined simply by the aggregation of characteristics of the practices per se , nor on the technologies used, but on whether 'empowerment' permeates the curriculum goal and process. Further, this paper claims that these affective and socio-cognitive learning outcomes are more important as preparation for lifelong learning in the 21st century than 'knowledge management competencies'.     

QLH-02裂解汽油二段加氢催化剂工业应用

通过载体改性及催化剂制备工艺研究,中国石化齐鲁分公司研究院成功开发了QLH-02低温型裂解汽油二段加氢催化剂。在中国石化齐鲁分公司烯烃厂裂解汽油二段加氢装置应用结果表明,该催化剂强度高,装填量少,在二段加氢反应器入口温度为265℃、压力为2.65 MPa、液体空速4.0 h-1、氢油体积比800~1 000的操作条件下,产品中硫含量小于1μg.g-1,双烯值(B r2值/100 mL,以下同)小于0.05 g,溴值(B r值/100 mL,以下同)小于0.09 g,远低于控制指标,具有很好的低温加氢活性,明显降低了能源消耗。     

ⅡB族同核准分子Hg2226.2nm漫射带研究

本文报导在高纯Ｈｇ蒸气石英放电管中首次观测到峰值位于２２６．２ｎｍ左右属于Ｈｇ２准分子ＧＯ＾＋ｕ→ＸＯ＾＋ｇ束缚→自由跃迁的漫射带辐射，实验测量了漫射带强度随放电电流、气体温度和密度的变化关系，获得漫射带最大信号输出的工作参量。