Coma measurement by use of an alternating phase-shifting mask mark with a specific phase width

The correlation between the coma sensitivity of the alternating phase-shifting mask (Alt-PSM) mark and the mark's structure is studied based on the Hopkins theory of partially coherent imaging and positive resist optical lithography (PROLITH) simulation. It is found that an optimized Alt-PSM mark with its phase width being two-thirds its pitch has a higher sensitivity to coma than Alt-PSM marks with the same pitch and the different phase widths. The pitch of the Alt-PSM mark is also optimized by PROLITH simulation, and the structure of p - 1.92 lambda/NA and pw = 2p/3 proves to be with the highest sensitivity. The optimized Alt-PSM mark is used as a measurement mark to retrieve coma aberration from the projection optics in lithographic tools. In comparison with an ordinary Alt-PSM mark with its phase width being a half its pitch, the measurement accuracies of Z(7) and Z(14) apparently increase. (C) 2009 Optical Society of America

Even aberration measurement of lithographic projection system based on optimized phase-shifting marks

In the present paper, we propose a novel method for measuring the even aberrations of lithographic projection optics by use of optimized phase-shifting marks on the test mask. The line/space ratio of the phase-shifting marks is optimized to obtain the maximum sensitivities of Zernike coefficients corresponding to even aberrations. Spherical aberration and astigmatism can be calculated from the focus shifts of phase-shifting gratings oriented at 0 degrees, 45 degrees, 90 degrees and 135 degrees at multiple illumination settings. The PROLITH simulation results show that, the measurement accuracy of spherical aberration and astigmatism obviously increase, after the optimization of the measurement mark. (C) 2008 Elsevier B.V. All rights reserved.

Narrowing of band gap and low-temperature spin glass behavior of FeNi co-doped ZnO nanowires

This letter reports on the Raman, optical and magnetic properties of FeNi co-doped ZnO nanowires prepared via a soft chemical solution method. The microstructural investigations show that the NiFe co-dopants are substituted into wurtzite ZnO nanostructure without forming any secondary phase. The co-doped nanowires show a remarkable reduction of 34 nm (267.9 meV) in the optical band gap, while suppression in the deep-level defect transition in visible luminescence. Furthermore, these nanowires exhibit ferromagnetism and an interesting low-temperature spin glass behavior, which may arise due to the presence of disorder and strong interactions of frustrated spin moments of Ni and Fe co-dopants on the ZnO lattice sites. Copyright (C) EPLA, 2009

Characterization and analysis of two-dimensional GaAs-based photonic crystal nanocavities at room temperature

This paper describes the design and fabrication process of a two-dimensional GaAs-based photonic crystal nanocavity and analyzes the optical characterization of cavity modes at room temperature. Single InAs/InGaAs quantum dots (QDs) layer was embedded in a GaAs waveguide layer grown on an Al0.7Ga0.3As layer and GaAs substrate. The patterning of the structure and the membrane release were achieved by using electron-beam lithography, reaction ion etching, inductively coupled plasma etching and selective wet etching. The micro-luminescence spectrum is recorded from the fabricated nanocavities, and it is found that some high-order cavity modes are clearly observed besides the lowest-order resonant mode is exhibited in spite of much high rate of nonradiative recombination. The variance of resonant modes is also discussed as a function of r/a ratio and will be used in techniques aimed to improve the probability of achieving spectral coupling of a single QD to a cavity mode.

一种问题驱动的经验软件工程研究方法与实践

随着软件应用领域的不断扩展，社会对软件产品的需求也在急剧膨胀。经过近三十年的锤炼与积累的经验教训，软件组织已不再以开发出满足用户需求的产品作为唯一的项目成功目标，而是将控制预算、提高生产率、更有效利用资源等方面都列入了考虑范围。 对于软件组织而言，要获得组织整体的长远发展，需要实施量化项目管理、开发过程控制、持续过程改进等一系列措施，在项目的不同时期设立合理的控制点和决策点来指导和监控项目的进行情况。当前，全球性分布式开发、敏捷开发与开源代码开发等已经形成了软件开发的新趋势；同时，大型软件企业在选择外包承接商时需要考虑众多因素，包括软件开发过程因素、人员因素、产品技术因素等多项可以为他们的决策提供辅助支持的信息。软件项目相关的决策支持除了组织内部需求以外，也存在于其他场景。例如，政府在进行软件资助项目挑选时、在购买合同软件时，也需要更客观更严谨的对这些项目予以评价并作出决策。 而种种这些软件行业的决策支持所需要的信息主要借鉴两方面信息源，一方面是在行业或市场背景下的软件组织所积累的特征和经验数据，另一方面是来自学术研究领域的相关理论和模型的支持。正是在这样的应用环境下，软件工程领域的经验研究在过去的二十多年里逐渐兴起(最后演变为“经验软件工程”这个独立的研究方向)，它强调从实际观察和历史数据中挖掘信息或设计一定的实验来进行对已有理论与模型的验证与推进。 本文以经验软件工程领域的研究特征为基础，提出了一种问题驱动的经验研究方法框架，以及遵循这个研究框架进行的实例化经验研究。其中主要的独创性内容包括： 提出了一种问题驱动的经验软件工程研究方法框架QD-ESE (Question-Driven Empirical Software Engineering)，其结构上由开发实践层、经验研究层、经验管理层三个部分组成。在经验研究步骤的进行过程中，融合经验软件工程的研究成果，通过三个部分的交互，实现经验研究所需信息支持与利用、数据分析、知识提取与经验积累等工作。 通过对QD-ESE框架的实例化应用，实现了针对工作量分布的经验研究，分析了市场演变等五个维度对产品演化项目中工作量分布的影响。该实例是针对软件项目中对工作量阶段分布预测的困难而提出的。其中基于某组织系列版本的产品开发数据，从市场演变、产品内容、开发过程、开发团队与采用技术五个维度，分析了它们对各版本项目中的工作量分布的具体影响，为开发组织在项目中的工作量阶段分配提炼并积累了可以借鉴的实际经验。 在针对生产率的经验研究实例中，得到对中国软件行业生产率整体状况的调查结果，并发掘出开发类型、业务领域、团队规模等多个影响生产率差异的显著因素。该实例研究是在中国软件行业缺乏产业数据及相应的重要指标基准问题的实际背景下提出的，尤其针对产品演化项目。遵循QD-ESE研究框架，并基于首次发布并可用的中国软件基准组数据，对软件开发生产率的影响因子进行了分析，为软件组织在提高生产率和改善开发过程方面提供了有价值的数据、信息和建议。 最后，QD-ESE研究框架在针对软件成本估算的经验研究实例中进一步得到应用，提出了一套针对政府软件合同定价的估算建模方法并在政府资助等实际项目中予以应用。该实例是在分析政府在软件项目合同定价中遇到的挑战并发现软件成本预算与核算中问题的实际背景下提出的。最终，提出了针对政府软件合同定价的COGOMO成本估算模型(COnstructive GOvernment cost MOdel)。

A data-model fusion approach for upscaling gross ecosystem productivity to the landscape scale based on remote sensing and flux footprint modelling

Chinese Academy of Sciences ; National Science Foundation of China [41071059]; National Key Technology R&D Program of China [2008BAK50B06-02]; National Basic Research Program of China [2010CB950900, 2010CB950704]; Natural Sciences and Engineering Research Council of Canada

Evaluation of the pyrolytic and kinetic characteristics of Enteromorpha prolifera as a source of renewable bio-fuel from the Yellow Sea of China

The pyrolytic and kinetic characteristics of Enteromorpha prolifera from the Yellow Sea were evaluated at heating rates of 10, 20 and 50 degrees C min(-1), respectively. The results indicated that three stages appeared during pyrolysis; dehydration, primary devolatilization and residual decomposition. Differences in the heating rates resulted in considerable differences in the pyrolysis of E. prolifera. Specifically, the increase of heating rates resulted in shifting of the initial temperature, peak temperature and the maximum weight loss to a higher value. The average activation energy of E. prolifera was 228.1 kJ mol(-1), the pre-exponential factors ranged from 49.93 to 63.29 and the reaction orders ranged from 2.2 to 3.7. In addition, there were kinetic compensation effects between the pre-exponential factors and the activation energy. Finally, the minimum activation energy was obtained when a heating rate of 20 degrees C min(-1) was used. (C) 2009 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

basic research in computer science and software engineering at sklcs

The State Key Laboratory of Computer Science (SKLCS) is committed to basic research in computer science and software engineering. The research topics of the laboratory include: concurrency theory, theory and algorithms for real-time systems, formal specifications based on context-free grammars, semantics of programming languages, model checking, automated reasoning, logic programming, software testing, software process improvement, middleware technology, parallel algorithms and parallel software, computer graphics and human-computer interaction. This paper describes these topics in some detail and summarizes some results obtained in recent years.

Mechanism for Giycinebetaine to Improve Plant Salt Resistance and Its Research Advances in Genetic Engineering

The paper systematically discusses the mechanism for glycinebetaine to improve plant salt resistance and its research advances in genetic engineering at home and abroad as well as summarizing the research progresses about the key enzymes and their genetic engineering in glycinebetaine biosynthesis. It suggests that on the basis of further understanding the mechanism for glycinebetaine to improve plant salt resistance,the transformation of the genes relating to glycinebetaine biosynthesis should be carried out in major crops so that new plant varieties resistant to salt can be obtained.